Seasonal and spatial variation of bacterial production and abundance in the northern Levantine Sea

Directory of Open Access Journals (Sweden)

N. YUCEL

2017-03-01

Full Text Available Spatial and temporal heterogeneity in bacterial production and abundance in relation to ambient bio-physicochemical parameters has been investigated in the Levantine Sea. Five stations with different trophic states in an area extending from highly eutrophic Mersin bay to the mesotrophic Rhodes gyre area including the oligotrophic offshore waters were sampled four times. Integrated bacterial production varied between 6.1 and 90.3 µg C m-2 d-1 with higher rates occurring during September 2012 in offshore waters. Bacterial abundance ranged between 0.18 and 7.3 x 105 cells ml-1 within the euphotic zone and was generally higher up to 100 meters throughout the study period. In offshore waters, bacterial production (0.401 to 0.050 µg C m-3 d-1, abundance (4.5 to 1.6 x 105 cells ml-1 and depth of the productive layer decreased from 150 to 75 meters westward along the transect. Although the highest abundance was observed in July 2012 in offshore waters, the highest activity was measured in September 2012. These results indicated that the temperature played a key role in regulating bacterial abundance and production in the area. High chlorophyll concentrations in March did not correspond to high bacterial abundance and production at the same time. Increase in dissolved organic carbon content following spring phytoplankton bloom and the increase in temperature in the mean time might have enhanced the bacterial activity towards summer.

Development of a compact ECR ion source for various ion production

Energy Technology Data Exchange (ETDEWEB)

Muramatsu, M., E-mail: m-mura@nirs.go.jp; Hojo, S.; Iwata, Y.; Katagiri, K.; Sakamoto, Y.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Takahashi, N. [Sumitomo Heavy Industries, Ltd., 19 Natsushima, Yokosuka, Kanagawa 237-8555 (Japan); Sasaki, N.; Fukushima, K.; Takahashi, K.; Suzuki, T.; Sasano, T. [Accelerator Engineering Corporation, 3-8-5 Konakadai, Inage, Chiba 263-0043 (Japan); Uchida, T.; Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama 350-8585 (Japan); Hagino, S.; Nishiokada, T.; Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

2016-02-15

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

Negative ion production by laser ablation

Energy Technology Data Exchange (ETDEWEB)

Wada, Motoi [Doshisha Univ., Tanabe, Kyoto (Japan). Faculty of Engineering; Sasao, Mamiko

1997-02-01

The status of the development of Li{sup -} production by generating a neutral Li flux with an intense radiation of a laser beam onto the surface of Li metal has been reported. The experimental apparatus was arranged to detect a mass separated Li{sup +} and Li{sup -} ion beams. A Li sputtering probe, immersed in the extraction region of a compact (6cm diam. 7cm long) magnetic multipole ion source was irradiated with a Nd-YAG laser of 0.4 J/pulse. The production of mass-separated positive ions of Li by laser irradiation has been confirmed, but the production of Li{sup -} has not been confirmed yet due to the noise caused by a temporal discharge. (author)

Impact of energetic cosmic-ray ions on astrophysical ice grains

International Nuclear Information System (INIS)

Mainitz, Martin; Anders, Christian; Urbassek, Herbert M.

2017-01-01

Highlights: • We use the REAX potential to model dissociations and reactions. • An ice grain consisting of a mixture of small molecules is considered. • The passage of a cosmic-ray ion initiates an ion track. • The track induces a shock wave and disintegrates the grain. • Abundant fragments and reaction products are detected. - Abstract: Using molecular-dynamics simulation with REAX potentials, we study the consequences of cosmic-ray ion impact on ice grains. The grains are composed of a mixture of H_2O, CO_2, NH_3, and CH_3OH molecules. Due to the high energy deposition of the cosmic-ray ion, 5 keV/nm, a strong pressure wave runs through the grain, while the interior of the ion track gasifies. Abundant molecular dissociations occur; reactions of the fragments form a variety of novel molecular product species.

Design and simulation of ion optics for ion sources for production of singly charged ions

Science.gov (United States)

Zelenak, A.; Bogomolov, S. L.

2004-05-01

During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments.

Design and simulation of ion optics for ion sources for production of singly charged ions

International Nuclear Information System (INIS)

Zelenak, A.; Bogomolov, S.L.

2004-01-01

During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments

Impact of energetic cosmic-ray ions on astrophysical ice grains

Energy Technology Data Exchange (ETDEWEB)

Mainitz, Martin; Anders, Christian; Urbassek, Herbert M., E-mail: urbassek@rhrk.uni-kl.de

2017-02-15

Highlights: • We use the REAX potential to model dissociations and reactions. • An ice grain consisting of a mixture of small molecules is considered. • The passage of a cosmic-ray ion initiates an ion track. • The track induces a shock wave and disintegrates the grain. • Abundant fragments and reaction products are detected. - Abstract: Using molecular-dynamics simulation with REAX potentials, we study the consequences of cosmic-ray ion impact on ice grains. The grains are composed of a mixture of H{sub 2}O, CO{sub 2}, NH{sub 3}, and CH{sub 3}OH molecules. Due to the high energy deposition of the cosmic-ray ion, 5 keV/nm, a strong pressure wave runs through the grain, while the interior of the ion track gasifies. Abundant molecular dissociations occur; reactions of the fragments form a variety of novel molecular product species.

Strangeness production in proton and heavy ion collisions at 200 A GeV

International Nuclear Information System (INIS)

Amelin, N.S.; Bravina, L.V.; Csernai, L.P.; Toneev, V.D.; Gudima, K.K.; Sivoklokov, S.Y.

1992-11-01

Strangeness production at SPS-CERN energies is studied within the Quark Gluon String Model. The observed shape of rapidity and transverse mass distributions are reproduced fairly well for both peripheral and central heavy ion collisions. However, for central collisions the model underpredicts strange particle abundances by a factor of about 2:2:4 for K S 0 , Λ and antiΛ, respectively. This discrepancy can be considered as a possible manifestation of collective string-string interactions similar to the formation of a color rope. Model predictions for coming experiments with the Pb beam at CERN are given. 30 refs. 11 figs., 3 tabs

Novel product ions of 2-aminoanilide and benzimidazole Ag(I) complexes using electrospray ionization with multi-stage tandem mass spectrometry.

Science.gov (United States)

Johnson, Byron S; Burinsky, David J; Burova, Svetlana A; Davis, Roman; Fitzgerald, Russ N; Matsuoka, Richard T

2012-05-15

The 2-aminoaniline scaffold is of significant value to the pharmaceutical industry and is embedded in a number of pharmacophores including 2-aminoanilides and benzimidazoles. A novel application of coordination ion spray mass spectrometry (CIS-MS) for interrogating the silver ion (Ag(+)) complexes of a homologous series of these compounds using multi-stage tandem mass spectrometry is described. Unlike the ubiquitous alkali metal ion complexes, Ag(+) complexes of 2-aminoanilides and benzimidazoles were found to yield [M - H](+) ions in significant abundance via gas-phase elimination of the metal hydride (AgH) resulting in unique product ion cascades. Sample introduction was by liquid chromatography with mass spectrometry analysis performed on a hybrid linear ion trap/orbitrap instrument capable of high-resolution measurements. Rigorous structural characterization by multi-stage tandem mass spectrometry using [M +  H](+), [M - H](-) and [M - H](+) precursor ions derived from ESI and CIS experiments was performed for the homologous series of 2-aminoanilide and benzimidazole compounds. A full tabular comparison of structural information resulting from these product ion cascades was produced. Multi-stage tandem mass spectrometry of [M - H](+) ions resulting from Ag(+) complexes of 2-aminoanilides and benzimidazoles in CIS-MS experiments produced unique product ion cascades that exhibited complementary structural information to that obtained from tandem mass spectrometry of [M  +  H](+) and [M - H](-) ions by electrospray ionization (ESI). These observations may be broadly applicable to other compounds that are observed to form Ag(+) complexes and eliminate AgH. Copyright © 2012 John Wiley & Sons, Ltd.

Target life time of laser ion source for low charge state ion production

Energy Technology Data Exchange (ETDEWEB)

Kanesue,T.; Tamura, J.; Okamura, M.

2008-06-23

Laser ion source (LIS) produces ions by irradiating pulsed high power laser shots onto the solid state target. For the low charge state ion production, laser spot diameter on the target can be over several millimeters using a high power laser such as Nd:YAG laser. In this case, a damage to the target surface is small while there is a visible crater in case of the best focused laser shot for high charge state ion production (laser spot diameter can be several tens of micrometers). So the need of target displacement after each laser shot to use fresh surface to stabilize plasma is not required for low charge state ion production. We tested target lifetime using Nd:YAG laser with 5 Hz repetition rate. Also target temperature and vacuum condition were recorded during experiment. The feasibility of a long time operation was verified.

Ion source developments for RNB production at Spiral / GANIL

International Nuclear Information System (INIS)

Villari, A.C.C.; Barue, C.; Gaubert, G.; Gibouin, S.; Huguet, Y.; Jardin, P.; Kandri-Rody, S.; Landre-Pellemoine, F.; Lecesne, N.; Leroy, R.; Lewitowicz, M.; Marry, C.; Maunoury, L.; Pacquet, J.Y.; Rataud, J.P.; Saint-Laurent, M.G.; Stodel, C.; Lichtenthaeler, R.; Angelique, J.C.; Orr, N.A.

2000-01-01

The first on-line production system for SPIRAL/GANIL (Radioactive Ion Production System with Acceleration on-Line) phase-I has been commissioned on the SIRa (Radioactive Ion Separator) test bench. Exotic multicharged noble gas ion beams have been obtained during several days. In parallel, a new ECRIS (Electron Cyclotron Resonance Ion Source) for mono-charged ions has also been developed. Preliminary, off-line results are presented. (authors)

Aquaponics: integrating fish feeding rates and ion waste production for strawberry hydroponics

International Nuclear Information System (INIS)

Villarroel, M.; Alvarino, J. M. R.; Duran, J. M.

2011-01-01

Aquaponics is the science of integrating intensive fish aquaculture with plant production in recirculating water systems. Although ion waste production by f ish cannot satisfy all plant requirements, less is known about the relationship between total feed provided for f ish and the production of milliequivalents (mEq) of different macronutrients for plants, especially for nutrient flow hydroponics used for strawberry production in Spain. That knowledge is essential to consider the amount of macronutrients available in aquaculture systems so that farmers can estimate how much nutrient needs to be supplemented in the waste water from fish, to produce viable plant growth. In the present experiment, tilapia (Oreochromis niloticus L.) were grown in a small-scale recirculating system at two different densities while growth and feed consumption were noted every week for five weeks. At the same time points, water samples were taken to measure pH, EC 2 5, HCO3 - , Cl - , NH + 4 , NO 2 - , NO 3 - , H 2 PO 4 - , SO 4 2 -, Na + , K + , Ca 2 + and Mg 2 + build up. The total increase in mEq of each ion per kg of feed provided to the fish was highest for NO 3 - , followed, in decreasing order, by Ca 2 +, H 2 PO 4 - , K + , Mg 2 + and SO 4 2 -. The total amount of feed required per mEq ranged from 1.61- 13.1 kg for the four most abundant ions (NO 3 - , Ca 2 +, H 2 PO 4 - and K + ) at a density of 2 kg fish m3, suggesting that it would be rather easy to maintain small populations of fish to reduce the cost of hydroponic solution supplementation for strawberries. (Author) 16 refs.

Production of highly charged ion beams from ECR ion sources

International Nuclear Information System (INIS)

Xie, Z.Q.

1997-09-01

Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ and U 34+ have been produced from ECR ion sources. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I ≥ 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams

Production techniques for rare earth and other heavy negative ions

International Nuclear Information System (INIS)

McK Hyder, H.R.; Ashenfelter, J.; McGrath, R.

1998-01-01

Current nuclear structure studies demand a wide range of heavy negative ion beams for tandem acceleration. Some of the wanted isotopes have low natural abundances and many have low or negative electron affinities. For these, gas injection or the use of hydrides, oxides, or fluorides is required to achieve usable intensities. The chemical properties of the target materials, and of the additive gases used to form molecular ions, often have detrimental effects on ion source performance and life. These effects include insulator breakdown, ionizer poisoning, and the erosion or deposition of material on critical electrodes. Methods of controlling sputter source conditions are being studied on the Wright Nuclear Structure Laboratory ion source test bench with the object of extending source life, increasing target efficiency, and achieving consistent negative ion outputs. Results are reported for several heavy ions including tellurium, neodymium, and ytterbium. copyright 1998 American Institute of Physics

Low charge state heavy ion production with sub-nanosecond laser.

Science.gov (United States)

Kanesue, T; Kumaki, M; Ikeda, S; Okamura, M

2016-02-01

We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

Low charge state heavy ion production with sub-nanosecond laser

Energy Technology Data Exchange (ETDEWEB)

Kanesue, T., E-mail: tkanesue@bnl.gov; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Kumaki, M. [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa 226-8503 (Japan)

2016-02-15

We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

Study of the on line radioactive multicharged ion production

International Nuclear Information System (INIS)

Lecesne, N.

1997-01-01

This work is directly related to the SPIRAL project (Systeme de Production d'Ions Radioactifs Acceleres en Ligne) which will start at GANIL at the end of 1998. The aim of the thesis was to study the on line radioactive multicharged ion beam production stages, i.e. the production and diffusion of the radioactive nuclei in a thick target, their possible transfer up to an ECR ion source and their ionisation. Production cross sections of radioactive neutron rich nuclei, formed by fragmentation of a heavy ion beam in a thick target, were measured. An external target-ECR source system, dedicated to the radioactive noble gases production, and two internal target-ECR source systems, dedicated to the radioactive condensable element production, were built and tested on the SIRa tests bench (Separateur d'Ions Radioactifs). Different detection configurations were elaborated in order to identify the radioactive nuclei and estimate their production yields. Finally, a new method for measuring the overall efficiency of the separator was developed and allowed to study the diffusion properties of radioactive noble gases in various targets. (author)

Double-differential heavy-ion production cross sections

International Nuclear Information System (INIS)

Miller, T. M.; Townsend, L. W.

2004-01-01

Current computational tools used for space or accelerator shielding studies transport energetic heavy ions either using a one-dimensional straight-ahead approximation or by dissociating the nuclei into protons and neutrons and then performing neutron and proton transport using Monte Carlo techniques. Although the heavy secondary particles generally travel close to the beam direction, a proper treatment of the light ions produced in these reactions requires that double-differential cross sections should be utilised. Unfortunately, no fundamental nuclear model capable of serving as an event generator to provide these cross sections for all ions and energies of interest exists currently. Herein, we present a model for producing double-differential heavy-ion production cross sections that uses heavy-ion fragmentation yields produced by the NUCFRG2 fragmentation code coupled with a model of energy degradation in nucleus-nucleus collisions and systematics of momentum distributions to provide energy and angular dependences of the heavy-ion production. (authors)

Production processes of multiply charged ions by electron impact

International Nuclear Information System (INIS)

Oda, Nobuo

1980-02-01

First, are compared the foil or gas stripper and the ion sources utilizing electron-atom ionizing collisions, which are practically used or are under development to produce multiply charged ions. A review is made of the fundamental physical parameters such as successive ionization potentials and various ionization cross sections by electron impact, as well as the primary processes in multiply charged ion production. Multiply charged ion production processes are described for the different existing ion sources such as high temperature plasma type, ion-trapping type and discharge type. (author)

Radioactive Ions Production Ring for Beta-Beams

CERN Document Server

Benedetto, E; Wehner, J

2010-01-01

Within the FP7 EUROnu program, Work Package 4 addresses the issues of production and acceleration of 8Li and 8B isotopes through the Beta-Beam complex, for the production of electron-neutrino. One of the major critical issues is the production of a high enougth ion ßux, to fulÞll the requirements for physics. In alternative to the direct ISOL production method, a new ap- proach is proposed in [1]. The idea is to use a compact ring for Litium ions at 25 MeV and an internal He or D target, in which the radioactive-isotopes production takes place. The beam is expected to survive for several thousands of turns, therefore cooling in 6D is required and, according this scheme, the ionization cooling provided by the target itself and a suitable RF system would be sufÞcient. We present some preliminary work on the Production ring lat- tice design and cooling issues, for the 7Li ions, and propose plans for future studies, within the EUROnu program.

Aquaponics: integrating fish feeding rates and ion waste production for strawberry hydroponics

Energy Technology Data Exchange (ETDEWEB)

Villarroel, M; Alvarino, J M. R.; Duran, J M

2011-07-01

Aquaponics is the science of integrating intensive fish aquaculture with plant production in recirculating water systems. Although ion waste production by fish cannot satisfy all plant requirements, less is known about the relationship between total feed provided for fish and the production of milliequivalents (mEq) of different macronutrients for plants, especially for nutrient flow hydroponics used for strawberry production in Spain. That knowledge is essential to consider the amount of macronutrients available in aquaculture systems so that farmers can estimate how much nutrient needs to be supplemented in the waste water from fish, to produce viable plant growth. In the present experiment, tilapia (Oreochromis niloticus L.) were grown in a small-scale recirculating system at two different densities while growth and feed consumption were noted every week for five weeks. At the same time points, water samples were taken to measure pH, EC25, HCO3{sup -}, Cl{sup -}, NH{sup +}{sub 4}, NO{sub 2}{sup -}, NO{sub 3}{sup -}, H{sub 2}PO{sub 4}{sup -}, SO{sub 4}{sup 2}-, Na{sup +}, K{sup +}, Ca{sup 2}+ and Mg{sup 2}+ build up. The total increase in mEq of each ion per kg of feed provided to the fish was highest for NO{sub 3}{sup -}, followed, in decreasing order, by Ca{sup 2}+, H{sub 2}PO{sub 4}{sup -}, K{sup +}, Mg{sup 2}+ and SO{sub 4}{sup 2}-. The total amount of feed required per mEq ranged from 1.61 - 13.1 kg for the four most abundant ions (NO{sub 3}{sup -}, Ca{sup 2}+, H{sub 2}PO{sub 4}{sup -} and K{sup +}) at a density of 2 kg fish m{sup -3}, suggesting that it would be rather easy to maintain small populations of fish to reduce the cost of hydroponic solution supplementation for strawberries. (Author) 16 refs.

Production of microbunched beams of very highly charged ions with an electron beam ion source

International Nuclear Information System (INIS)

Stoeckli, M.P.

1998-01-01

Electron beam ion sources produce very highly charged ions most efficiently in a batch mode as the confinement time can be directly optimized for the production of the desired charge state. If, after confinement, the voltage of the ion-confining downstream dam is lowered rapidly, all ions escape and form an ion beam pulse with a length of a few tens of μs. Raising the main trap voltage while maintaining a constant dam voltage in a open-quotes spill-over expulsionclose quotes reduces the energy spread of the expelled ions. The longer time periods of open-quotes slow-,close quotes open-quotes leaky batch mode-,close quotes and open-quotes direct current (dc) batch mode-close quotes expulsions allow for increasing the ion beam duty cycle. Combining the rapid expulsion with one of the latter methods allows for the expulsion of the ions of a single batch in many small microbunches with variable intervals, maintaining the low energy spread and the increased duty cycle of slow expulsions. Combining the open-quotes microbunchingclose quotes with open-quotes dc batch mode productionclose quotes and a multitrap operation will eventually allow for the production of equally intense ion bunches over a wide range of frequencies without any deadtime, and with minimal compromise on the most efficient production parameters. copyright 1998 American Institute of Physics

Production of highly charged ion beams with SECRAL

International Nuclear Information System (INIS)

Sun, L. T.; Zhao, H. W.; Zhang, X. Z.; Feng, Y. C.; Li, J. Y.; Guo, X. H.; Ma, H. Y.; Zhao, H. Y.; Ma, B. H.; Wang, H.; Li, X. X.; Jin, T.; Xie, D. Z.; Lu, W.; Cao, Y.; Shang, Y.

2010-01-01

Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e μA of Xe 37+ , 1 e μA of Xe 43+ , and 0.16 e μA of Ne-like Xe 44+ . To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi 31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e μA of Bi 31+ , 22 e μA of Bi 41+ , and 1.5 e μA of Bi 50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.

Effect of electrode materials on a negative ion production in a cesium seeded negative ion source

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Takashi; Morishita, Takutoshi; Kashiwagi, Mieko; Hanada, Masaya; Iga, Takashi; Inoue, Takashi; Watanabe, Kazuhiro; Imai, Tsuyoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Wada, Motoi [Doshisha Univ., Kyoto (Japan)

2003-03-01

Effects of plasma grid materials on the negative ion production efficiency in a cesium seeded ion source have been experimentally studied. Grid materials of Au, Ag, Cu, Ni, and Mo were examined. A 2.45 GHz microwave ion source was utilized in the experiment to avoid contamination of tungsten from filament cathode. Relations between the negative ion currents and work functions of the grid were measured for these materials. Influence of the contamination by tungsten on the grid was also investigated. If was clarified that the negative ion production efficiency was determined only by the work function of the grid. The efficiency did not depend on the material itself. The lowest work function of 1.42 eV was obtained for Au grid with Cs, and a high H{sup -} production efficiency of 20.7 mA/kW was measured. This efficiency is about 1.3 times larger than that of Cs/Mo and Cs/Cu. Further improvement of the production efficiency was observed by covering the plasma grid with tungsten and cesium simultaneously. Such co-deposition of W and Cs on the plasma grid produced the negative ion production efficiency of 1.7 times higher than that from the tungsten grid simply covered with Cs. (author)

Ion cyclotron emission due to collective instability of fusion products and beam ions in TFTR and JET

International Nuclear Information System (INIS)

Dendy, R.O.; McClements, K.G.; Lashmore Davies, C.N.; Cottrell, G.A.; Majeski, R.; Cauffman, S.

1995-01-01

Ion cyclotron emission (ICE) has been observed from neutral beam heated TFTR and JET tritium experiments at sequential cyclotron harmonics of both fusion products and beam ions. The emission originates from the outer midplane plasma, where fusion products and beam ions are likely to have a drifting ring-type velocity-space distribution that is anisotropic and sharply peaked. Fusion product driven ICE can be attributed to the magnetoacoustic cyclotron instability, which involves the excitation of obliquely propagating waves on the fast Alfven/ion Bernstein branch at cyclotron harmonics of the fusion products. Differences between ICE observations in JET and TFTR appear to reflect the sensitivity of the instability growth rate to the ratio υ birth /c A , where υ birth is the fusion product birth speed and c A is the local Alfven speed: for fusion products in the outer midplane edge of TFTR supershots, υ birth A ; for alpha particles in the outer midplane edge of JET, the opposite inequality applies. If sub-Alfvenic fusion products are isotropic or have undergone even a moderate degree of thermalization, the magnetoacoustic instability cannot occur. In contrast, the super-Alfvenic alpha particles that are present in the outer midplane of JET can drive the magnetoacoustic cyclotron instability even if they are isotropic or have a relatively broad distribution of speeds. These conclusions may account for the observation that fusion product driven ICE in JET persists for longer than fusion product driven ICE in TFTR. A separate mechanism is proposed for the excitation of beam driven ICE in TFTR: electrostatic ion cyclotron harmonic waves, supported by strongly sub-Alfvenic beam ions, can be destabilized by a low concentration of such ions with a very anrrow spread of velocities in the parallel direction. 25 refs, 14 figs

Overview of electromagnetic probe production in ultra-relativistic heavy ion collisions

International Nuclear Information System (INIS)

Paquet, Jean-François

2017-01-01

An introductory overview of electromagnetic probe production in ultra-relativistic heavy ion collisions is provided. Experimental evidence supporting the production of thermal photons and dileptons in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) are reviewed. Thermal electromagnetic probe production from hydrodynamical models of collisions is discussed. (paper)

Radioactive ion beam production by the ISOL method for SPIRAL

International Nuclear Information System (INIS)

Landre-Pellemoine, Frederique

2001-01-01

This work is directly related to the SPIRAL project (Systeme de Production d'Ions Radioactifs Acceleres en Lignes) of which the start up will begin in September 2001 at GANIL (Grand Accelerateur National d'Ions Lourds) in Caen. This thesis primarily concerns the development of radioactive ion production systems (target/ion source) by the thorough study of each production stage of the ISOL (Isotopic Separation On Line) method: target and/or projectile fragmentation production, diffusion out of target material, effusion into the ion source and finally the ionization of the radioactive atoms. A bibliographical research and thermal simulations allowed us to optimize materials and the shape of the production and diffusion targets. A first target was optimized and made reliable for the radioactive noble gases production (argon, neon...). A second target dedicated to the radioactive helium production was entirely designed and realised (from the specifications to the 'off line' and 'on line' tests). Finally, a third target source system was defined for singly-charged radioactive alkaline production. The intensities of secondary beams planned for SPIRAL are presented here. A detailed study of the diffusion effusion efficiency for these various targets showed that the use of a fine microstructure carbon (grain size of 1 μm) improved the diffusion and showed the importance of thickness of the lamella for the short lived isotope effusion. (author) [fr

New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited).

Science.gov (United States)

Zhao, H Y; Zhang, J J; Jin, Q Y; Liu, W; Wang, G C; Sun, L T; Zhang, X Z; Zhao, H W

2016-02-01

A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 10(13) W cm(-2) in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.

Effect of heavy ion irradiation on sucrose radical production

International Nuclear Information System (INIS)

Nakagawa, Kouichi; Sato, Yukio

2004-01-01

We investigated sucrose radicals produced by heavy-ion irradiation with various LETs (linear energy transfer) and the possibility for a sucrose ESR (electron spin resonance) dosimeter. The obtained spectral pattern was the same as that for helium (He) ions, carbon (C) ions, neon (Ne) ions, argon (Ar) ions, and iron (Fe) ions. Identical spectra were measured after one year, but the initial intensities decreased by a few percent when the samples were kept in ESR tubes with the caps at ambient temperature. The total spin concentration obtained by heavy-ion irradiation had a linear relation with the absorbed dose, and correlated logarithmically with the LET. Qualitative ESR analyses showed that the production of sucrose radicals depended on both the particle identity and the LET at the same dose. The production of spin concentration by He ions was the most sensitive to LET. Empirical relations between the LET and the spin yield for various particles imply that the LET at a certain dose can be estimated by the spin concentration. (authors)

Production of High-Intensity, Highly Charged Ions

CERN Document Server

Gammino, S.

2013-12-16

In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyclotron resonance ion sources (ECRIS). Multiple ionization is also obtained in laser-generated plasmas (laser ion sources (LIS)), where the high-energy electrons and the extremely high electron density allow step-by-step ionization, but the reproducibility is poor. This chapter discusses the atomic physics background at the basis of the production of highly charged ions and describes the scientific and technological features of the most advanced ion sources. Particular attention is paid to ECRIS and the latest developments, since they now r...

Reactions of BBr(n)(+) (n = 0--2) at fluorinated and hydrocarbon self-assembled monolayer surfaces: observations of chemical selectivity in ion--surface scattering.

Science.gov (United States)

Wade, N; Shen, J; Koskinen, J; Cooks, R G

2001-07-01

Ion-surface reactions involving BBr(n)(+) (n = 0--2) with a fluorinated self-assembled monolayer (F-SAM) surface were investigated using a multi-sector scattering mass spectrometer. Collisions of the B(+) ion yield BF(2)(+) at threshold energy with the simpler product ion BF(+)* appearing at higher collision energies and remaining of lower abundance than BF(2)(+) at all energies examined. In addition, the reactively sputtered ion CF(+) accompanies the formation of BF(2)(+) at low collision energies. These results stand in contrast with previous data on the ion-surface reactions of atomic ions with the F-SAM surface in that the threshold and most abundant reaction products in those cases involved the abstraction of a single fluorine atom. Gas-phase enthalpy data are consistent with BF(2)(+) being the thermodynamically favored product. The fact that the abundance of BF(2)(+) is relatively low and relatively insensitive to changes in collision energy suggests that this reaction proceeds through an entropically demanding intermediate at the vacuum--surface interface, one which involves interaction of the B(+) ion simultaneously with two fluorine atoms. By contrast with the reaction of B(+), the odd-electron species BBr(+)* reacts with the F-SAM surface to yield an abundant single-fluorine abstraction product, BBrF(+). Corresponding gas-phase ion--molecule experiments involving B(+) and BBr(+)* with C(6)F(14) also yield the products BF(+)* and BF(2)(+), but only in extremely low abundances and with no preference for double fluorine abstraction. Ion--surface reactions were also investigated for BBr(n)(+) (n = 0-2) with a hydrocarbon self-assembled monolayer (H-SAM) surface. Reaction of the B(+) ion and dissociative reactions of BBr(+)* result in the formation of BH(2)(+), while the thermodynamically less favorable product BH(+)* is not observed. Collisions of BBr(2)(+) with the H-SAM surface yield the dissociative ion-surface reaction products, BBrH(+) and BBrCH(3

Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

International Nuclear Information System (INIS)

Sun, L.; Lu, W.; Zhang, W. H.; Feng, Y. C.; Qian, C.; Ma, H. Y.; Zhang, X. Z.; Zhao, H. W.; Guo, J. W.; Yang, Y.; Fang, X.

2016-01-01

At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω 2 scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE 01 and HE 11 modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar 12+ , 0.92 emA Xe 27+ , and so on, will be presented

Mechanisms for pion production in heavy ion collisions

International Nuclear Information System (INIS)

Pfeiffer, M.

1991-01-01

In the following contribution some aspects concerning pion production in heavy ion collisions will be discussed. After a general introduction the properties of pions and the Δ-resonance will be briefly mentioned. In the following section some points refering to the pion production in a relativistic heavy ion collision will be discussed. In addition, the basic ideas of the applied models will be shown. In the last part results from existing experiments and possible interpretations will be presented. (orig.)

Terrestrial aurora: astrophysical laboratory for anomalous abundances in stellar systems

Directory of Open Access Journals (Sweden)

I. Roth

2014-02-01

Full Text Available The unique magnetic structure of the terrestrial aurora as a conduit of information between the ionosphere and magnetosphere can be utilized as a laboratory for physical processes at similar magnetic configurations and applied to various evolutionary phases of the solar (stellar system. The most spectacular heliospheric abundance enhancement involves the 3He isotope and selective heavy elements in impulsive solar flares. In situ observations of electromagnetic waves on active aurora are extrapolated to flaring corona in an analysis of solar acceleration processes of 3He, the only element that may resonate strongly with the waves, as well as heavy ions with specific charge-to-mass ratios, which may resonate weaker via their higher gyroharmonics. These results are applied to two observed anomalous astrophysical abundances: (1 enhanced abundance of 3He and possibly 13C in the late stellar evolutionary stages of planetary nebulae; and (2 enhanced abundance of the observed fossil element 26Mg in meteorites as a decay product of radioactive 26Al isotope due to interaction with the flare-energized 3He in the early solar system.

Ion-cyclotron instability in plasmas described by product-bi-kappa distributions

International Nuclear Information System (INIS)

Santos, M. S. dos; Ziebell, L. F.; Gaelzer, R.

2015-01-01

The dispersion relation for parallel propagating waves in the ion-cyclotron branch is investigated numerically by considering that the velocity distribution of the ion population is a function of type product-bi-kappa. We investigate the effects of the non-thermal features and of the anisotropy associated with this type of distribution on the ion-cyclotron instability, as well as the influence of different forms of the electron distribution, by considering Maxwellian distributions, bi-kappa distributions, and product-bi-kappa distributions. The cases of ions described by either Maxwellian or bi-kappa distributions are also considered, for comparison. The results of the numerical analysis show that the increase in the non-thermal character associated with the anisotropic kappa distributions for ions contributes to enhance the instability as compared to that obtained in the Maxwellian case, in magnitude and in wave number range, with more significant enhancement for the case of ion product-bi-kappa distributions than for the case of ion bi-kappa distributions. It is also shown that the ion-cyclotron instability is decreased if the electrons are described by product-bi-kappa distributions, while electrons described by bi-kappa distributions lead to growth rates which are very similar to those obtained considering a Maxwellian distribution for the electron population

Interference in Exclusive Vector Meson Production in Heavy-Ion Collisions

International Nuclear Information System (INIS)

Klein, Spencer R.; Nystrand, Joakim

2000-01-01

Vector mesons are produced copiously in peripheral relativistic heavy-ion collisions. Virtual photons from one ion can fluctuate into quark-antiquark pairs and scatter from the second ion, emerging as vector mesons. The emitter and target are indistinguishable, so emission from the two ions will interfere. Vector mesons have negative parity so the interference is destructive, reducing the production of mesons with small transverse momentum. The mesons are short lived, and decay before emission from the two ions can overlap. However, the decay-product wave functions overlap and interfere since they are produced in an entangled state, providing an example of the Einstein-Podolsky-Rosen paradox. (c) 2000 The American Physical Society

Production of Endohedral Fullerenes by Ion Implantation

Energy Technology Data Exchange (ETDEWEB)

Diener, M.D.; Alford, J. M.; Mirzadeh, S.

2007-05-31

The empty interior cavity of fullerenes has long been touted for containment of radionuclides during in vivo transport, during radioimmunotherapy (RIT) and radioimaging for example. As the chemistry required to open a hole in fullerene is complex and exceedingly unlikely to occur in vivo, and conformational stability of the fullerene cage is absolute, atoms trapped within fullerenes can only be released during extremely energetic events. Encapsulating radionuclides in fullerenes could therefore potentially eliminate undesired toxicity resulting from leakage and catabolism of radionuclides administered with other techniques. At the start of this project however, methods for production of transition metal and p-electron metal endohedral fullerenes were completely unknown, and only one method for production of endohedral radiofullerenes was known. They therefore investigated three different methods for the production of therapeutically useful endohedral metallofullerenes: (1) implantation of ions using the high intensity ion beam at the Oak Ridge National Laboratory (ORNL) Surface Modification and Characterization Research Center (SMAC) and fullerenes as the target; (2) implantation of ions using the recoil energy following alpha decay; and (3) implantation of ions using the recoil energy following neutron capture, using ORNL's High Flux Isotope Reactor (HFIR) as a thermal neutron source. While they were unable to obtain evidence of successful implantation using the ion beam at SMAC, recoil following alpha decay and neutron capture were both found to be economically viable methods for the production of therapeutically useful radiofullerenes. In this report, the procedures for preparing fullerenes containing the isotopes {sup 212}Pb, {sup 212}Bi, {sup 213}Bi, and {sup 177}Lu are described. None of these endohedral fullerenes had ever previously been prepared, and all of these radioisotopes are actively under investigation for RIT. Additionally, the chemistry for

Targets for production of high-intensity radioactive ion-beams

International Nuclear Information System (INIS)

Hagebo, E.; Hoff, P.; Steffensen, K.

1991-01-01

The recent developments of target systems for production of high intensity radioactive ion-beams at the ISOLDE mass separators is described. Methods for chemically selective production through separation of molecular ions are outlined and the effects of the addition of reactive gases has been studied. Results and further possible applications in the light element region are discussed. (author) 10 refs.; 9 figs.; 1 tab

Low mass dilepton production in heavy ion collisions

International Nuclear Information System (INIS)

Pisutova, N.; Pisut, J.

1988-01-01

The total transverse energy dependence of low mass dilepton (and single low p T photon) production was demonstrated to be a signature of the onset of the evidence of plasma formation in heavy ion collisions. Cross-sections are presented for low mass dilepton production in proton-nucleus and heavy ion collisions which represent lower bounds for the ''collectivization'' and the thermalization of matter produced in the collision. Higher cross-section are a signature of the onset of the formation of thermalized matter. (author). 4 figs., 11 refs

Nanophotonic production, modulation and switching of ions by silicon microcolumn arrays

Science.gov (United States)

Vertes, Akos; Walker, Bennett N.

2013-09-10

The production and use of silicon microcolumn arrays that harvest light from a laser pulse to produce ions are described. The systems of the present invention seem to behave like a quasi-periodic antenna array with ion yields that show profound dependence on the plane of laser light polarization and the angle of incidence. By providing photonic ion sources, this enables enhanced control of ion production on a micro/nano scale and direct integration with miniaturized analytical devices.

High charge state metal ion production in vacuum arc ion sources

International Nuclear Information System (INIS)

Brown, I.G.; Anders, A.; Anders, S.

1994-01-01

The vacuum arc is a rich source of highly ionized metal plasma that can be used to make a high current metal ion source. Vacuum arc ion sources have been developed for a range of applications including ion implantation for materials surface modification, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. Typically the source is repetitively pulsed with pulse length of order a millisecond and duty cycle or order 1% and operation of a dc embodiment has been demonstrated also. Beams have been produced from over 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with peak (pulsed) beam current up to several amperes. The ion charge state distribution has been extensively studied. Ion spectra have been measured for a wide range of metallic cathode materials, including Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U, as well as compound and alloy cathode materials such as TiC, SiC, UC, PbS, brass, and stainless steel. The ions generated are in general multiply-stripped with a mean charge state of from 1 to 3, depending on the particular metal species, and the charge state distribution can have components from Q = 1+ to 6+. Here the authors review the characteristics of vacuum arc ion sources from the perspective of their high charge state metal ion production

Production of highly charged ion beams from electron cyclotron resonance ion sources (invited)

International Nuclear Information System (INIS)

Xie, Z.Q.

1998-01-01

Electron cyclotron resonance ion source (ECRIS) development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields, and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECRISs. So far at continuous wave (CW) mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ , and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ , and U 34+ were produced from ECRISs. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ , and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I≥60enA) were also achieved. This article will review the ECR ion source progress and discuss key requirement for ECRISs to produce the highly charged ion beams. copyright 1998 American Institute of Physics

Are neutral loss and internal product ions useful for top-down protein identification?

Science.gov (United States)

Xiao, Kaijie; Yu, Fan; Fang, Houqin; Xue, Bingbing; Liu, Yan; Li, Yunhui; Tian, Zhixin

2017-05-08

Neutral loss and internal product ions have been found to be significant in both peptide and protein tandem mass spectra and they have been proposed to be included in database search and for protein identification. In addition to common canonical b/y ions in collision-based dissociation or c/z ions in electron-based dissociation, inclusion of neutral loss and internal product ions would certainly make better use of tandem mass spectra data; however, their ultimate utility for protein identification with false discovery rate control remains unclear. Here we report our proteome-level utility benchmarking of neutral loss and internal product ions with tandem mass spectra of intact E. coli proteome. Utility of internal product ions was further evaluated at the protein level using selected tandem mass spectra of individual E. coli proteins. We found that both neutral loss and internal products ions do not have direct utility for protein identification when they were used for scoring of P Score; but they do have indirect utility for provision of more canonical b/y ions when they are included in the database search and overlapping ions between different ion types are resolved. Tandem mass spectrometry has evolved to be a state-of-the-art method for characterization of protein primary structures (including amino acid sequence, post-translational modifications (PTMs) as well as their site location), where full study and utilization tandem mass spectra and product ions are indispensable. This primary structure information is essential for higher order structure and eventual function study of proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

Composition of heavy ions in solar energetic particle events

International Nuclear Information System (INIS)

Fan, C.Y.; Gloeckler, G.

1983-01-01

Recent advances in determining the elemental, charge state, and isotopic composition of approximatelt 1 to 20 MeV per nucleon ions in solar energetic particle (SEP) events and outline our current understanding of the nature of solar and interplanetary processes which may explain the observations. Average values of relative abundances measured in a large number of SEP events were found to be roughly energy independent in the approx. 1 to approx. 20 MeV per nucleon range, and showed a systematic deviation from photospheric abundances which seems to be organized in terms of the first ionization potential of the ion. Direct measurements of the charge states of SEPs revealed the surprisingly common presence of energetic He(+) along with heavy ion with typically coronal ionization states. High resolution measurements of isotopic abundance ratios in a small number of SEP events showed these to be consistent with the universal composition except for the puzzling overabundance of the SEP(22)Ne/(20)Ne relative to this isotopes ratio in the solar wind. The broad spectrum of observed elemental abundance variations, which in their extreme result in composition anomalies characteristic of (3)He rich, heavy ion rich and carbon poor SEP events, along with direct measurements of the ionization states of SEPs provided essential information on the physical characteristics of, and conditions in the source regions, as well as important constraints to possible models for SEP production

Heavy ion physics at CERN

International Nuclear Information System (INIS)

Vesztergombi, G.

1991-01-01

A summary of the present status and future plans for heavy ion experiments at CERN-SPS and CERN-LHC accelerators is given. The planned three phases give possibilities to study the properties of the quark-gluon-plasma (QGP). At the present stage the feasibility of high energy ion-ion experiments with their very abundant secondary hadron production, shows that there is a chance to obtain high densities, and to look for the onset of new, collective phenomena. In a second phase, there should be a chance to obtain more conclusive evidence for the onset of quark deconfinement. In the third stage, the average energy densities rise above the deconfinement threshold, so that a study of the properties of QGP should become possible. (G.P.)

Study on a volume-production H- ion source

International Nuclear Information System (INIS)

Takama, S.

1988-01-01

H - ions formed by volume-production are extracted from a multicuspion source. By applying a large positive bias to the plasma electrode, the ratio I - /I e becomes 1/20. H - ion current of 0.4mA is extracted from a 0.3cm 2 circular aperture at an arc current of 10A. (author)

Radioactive ion beam production challenges at the Holifield Heavy Ion Research Facility

International Nuclear Information System (INIS)

Meigs, M.J.; Alton, G.D.; Dowling, D.T.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Mills, G.D.; Mosko, S.W.; Olsen, D.K.; Tatum, B.A.

1992-01-01

The radioactive ion beam (RIB) project at the Holifield Heavy Ion Research Facility (HHIRF) will provide for reconfiguration of the HHIRF accelerator system to enable provision of low-intensity RIBs for nuclear and astrophysics research. As we have progressed with the design of the reconfiguration, we have encountered several challenges that were not immediately obvious when first contemplating the project. The challenges do not seem insurmountable but should keep life interesting for those of us doing the work. A brief review of the project will allow a better understanding of the challenges in RIB production. Radioactive ion beams will be produced with the Isotope Separator On-Line (ISOL) postacceleration technique. In particular, radioactive atoms will be produced by reactions in the thick stopping target of an ISOL-type target-ion source assembly using intense beams from the Oak Ridge Isochronous Cyclotron equipped with a light-ion internal source. This ISOL target-ion source assembly will be mounted on a high-voltage platform with a mass separator. The target ion source will operate at potentials up to 50 kV with respect to the high voltage platform. The radioactive atoms produced by nuclear reactions in the target diffuse to the surface of the heated target material, desorb from this surface, and effuse through a heated transfer tube into an ion source where ionization and extraction take place. Two types of ion sources will be initially considered. A Forced Electron Beam Induced Arc Discharge source, similar to those used by the ISOLDE facility at CERN and by the UNISOR facility at ORNL, will be built to produce positive ions. These positive ions will be focused through an alkali vapor charge-exchange canal to produce negative ions for tandem injection. In addition, a direct negative surface ionization addition or modification to the above source will be built and investigated

Energy deposition and ion production from thermal oxygen ion precipitation during Cassini's T57 flyby

Science.gov (United States)

Snowden, Darci; Smith, Michael; Jimson, Theodore; Higgins, Alex

2018-05-01

Cassini's Radio Science Investigation (RSS) and Langmuir Probe observed abnormally high electron densities in Titan's ionosphere during Cassini's T57 flyby. We have developed a three-dimensional model to investigate how the precipitation of thermal magnetospheric O+ may have contributed to enhanced ion production in Titan's ionosphere. The three-dimensional model builds on previous work because it calculates both the flux of oxygen through Titan's exobase and the energy deposition and ion production rates in Titan's atmosphere. We find that energy deposition rates and ion production rates due to thermal O+ precipitation have a similar magnitude to the rates from magnetospheric electron precipitation and that the simulated ionization rates are sufficient to explain the abnormally high electron densities observed by RSS and Cassini's Langmuir Probe. Globally, thermal O+ deposits less energy in Titan's atmosphere than solar EUV, suggesting it has a smaller impact on the thermal structure of Titan's neutral atmosphere. However, our results indicate that thermal O+ precipitation can have a significant impact on Titan's ionosphere.

Mechanisms for production of highly charged ions

International Nuclear Information System (INIS)

McGuire, J.H.

1987-01-01

Various experimental data at high collision velocity are interpreted in terms of direct (D) and rearrangement (R) mechanisms for production of multiply charged ions. We consider double ionization in helium by protons, electrons, heavy ions, antiprotons, positrons and photons. Qualitative differences are discussed in the context of the R and D mechanisms. Multiple ionization in many electron atoms is considered as is simultaneous capture and ionization and fragmentation of methane molecules. Some other theoretical methods are briefly discussed. (orig.)

Ion cyclotron emission due to collective instability of fusion products and beam ions in TFTR and JET

International Nuclear Information System (INIS)

Dendy, R.O.; Clements, K.G.; Lashmore-Davies, C.N.; Cottrell, G.A.; Majeski, R.; Cauffman, S.

1995-06-01

Ion cyclotron emission (ICE) has been observed from neutral beam-heated TFTR and JET tritium experiments at sequential cyclotron harmonics of both fusion products and beam ions. The emission originates from the outer mid-plane plasma, where fusion products and beam ions are likely to have a drifting ring-type velocity-space distribution which is anisotropic and sharply peaked. Fusion product-driven ICE in both TFTR and JET can be attributed to the magnetoacoustic cyclotron instability, which involves the excitation of obliquely propagating waves on the fast Alfven/ion Bernstein branch at cyclotron harmonics of the fusion products. Differences between ICE observations in JET and TFTR appear to reflect the sensitivity of the instability growth rate to the ratio υ birth /c A , where υ birth is the fusion product birth speed and c A is the local Alfven speed:for fusion products in the outer midplane edge of TFTR, υ birth A ; for alpha-particles in the outer midplane edge of JET, the opposite inequality applies. If sub-Alfvenic fusion products are isotropic or have undergone even a moderate degree of thermalization, the magnetoacoustic instability cannot occur. In contrast, the super-Alfvenic alpha-particles which are present in the outer mid-plane of JET can drive the magnetoacoustic cyclotron instability even if they are isotropic or have a relatively broad distribution of speeds. These conclusions may account for the observation that fusion product-driven ICE in JET persists for longer than fusion product-driven ICE in TFTR. (Author)

Study of Au- production in a plasma-sputter type negative ion source

International Nuclear Information System (INIS)

Okabe, Yushirou.

1991-10-01

A negative ion source of plasma-sputter type has been constructed for the purpose of studying physical processes which take place in the ion source. Negative ions of gold are produced on the gold target which is immersed in an argon discharge plasma and biased negatively with respect to the plasma. The work function of the target surface was lowered by the deposition of Cs on the target. An in-situ method has been developed to determine the work function of the target surface in the ion source under discharge conditions. The observed minimum work function of a cesiated gold surface in an argon plasma was 1.3 eV, when the negative ion production rate took the maximum value. The production rate increased monotonically and saturated when the surface work function was reduced from 1.9 eV to 1.3 eV. The dependence of Au - production rate on the incident ion energy and on the number of the incident ion was studied. From the experimental results, it is shown that the sputtering process is an important physical process for the negative ion production in the plasma-sputter type negative ion source. The energy distribution function was also measured. When the bias voltage was smaller than 280 V, the high energy component in the distribution decreased as the target voltage was decreased. Therefore, the energy spread ΔE, of the observed negative ion energy distribution also decreased. This tendency is also seen in the energy spectrum of Cu atoms sputtered in normal direction by Ar + ions. (J.P.N.)

Research and development for the production of radioactive ions for SPIRAL; Recherche et developpement concernant la production d'ions radioactifs dans le cadre de SPIRAL

Energy Technology Data Exchange (ETDEWEB)

Eleon, C

2007-12-15

This thesis is related to the research and development program for the production of radioactive ion beams by the ISOL method for SPIRAL at GANIL. Two studies concerning improvements to the performance of SPIRAL target-source system have been made, using a statistical approach to the atoms-to-ions transformation. The first study concerns the transformation time between the production of the radioactive atoms of Ar{sup 35} inside a target and the extraction of the radioactive ions from the source with the TARGISOL set-up (target + ECR source). The goal was to determine the diffusion coefficients of the Ar for the carbon target. The results that are presented illustrate the difficulty of this work. The second study is the application of the statistical approach to the surface ionization source. It allowed one to define and to build a new MonoNaKe set-up for the production of 1{sup +} radioactive alkaline ions. Radioactive ions of K{sup 37,47}, Na{sup 25,26,27,28,30}, Li{sup 8,9} and Al{sup 28,29,30,31} were produced. For the production of the multicharged radioactive alkali ions, the MonoNaKe target/ion-source system was coupled to the ECR source of SPIRAL-1 without a mass separator (1{sup +}/N{sup +} direct method). A first radioactive ion beam of {sup 47}K{sup 5+} was extracted at the SIRa test bench. A surface ionization test source based on the same technical characteristics of MonoNaKe has been built. The goal of this system will be to define a prototype of source adapted to the constraints of SPIRAL-2 (ionization efficiency and lifetime). (author)

Jet production in heavy ion collisions

CERN Document Server

Calucci, G

2000-01-01

We discuss the production of jets in heavy ion collisions at LHC. The process allows one to determine to a good accuracy the value of the impact parameter of the nuclear collision in each single inelastic event. The knowledge of the geometry is a powerful tool for a detailed analysis of the process, making it possible to test the various different elements which, in accordance with present theoretical ideas, take part to the production mechanism. (8 refs).

Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

International Nuclear Information System (INIS)

Nakagawa, T.

2014-01-01

The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams

Effects of Solvent and Ion Source Pressure on the Analysis of Anabolic Steroids by Low Pressure Photoionization Mass Spectrometry.

Science.gov (United States)

Liu, Chengyuan; Zhu, Yanan; Yang, Jiuzhong; Zhao, Wan; Lu, Deen; Pan, Yang

2017-04-01

Solvent and ion source pressure were two important factors relating to the photon induced ion-molecule reactions in low pressure photoionization (LPPI). In this work, four anabolic steroids were analyzed by LPPI mass spectrometry. Both the ion species present and their relative abundances could be controlled by switching the solvent and adjusting the ion source pressure. Whereas M •+ , MH + , [M - H 2 O] + , and solvent adducts were observed in positive LPPI, [M - H] - and various oxidation products were abundant in negative LPPI. Changing the solvent greatly affected formation of the ion species in both positive and negative ion modes. The ion intensities of the solvent adduct and oxygen adduct were selectively enhanced when the ion source pressure was elevated from 68 to 800 Pa. The limit of detection could be decreased by increasing the ion source pressure. Graphical Abstract ᅟ.

Effects of Solvent and Ion Source Pressure on the Analysis of Anabolic Steroids by Low Pressure Photoionization Mass Spectrometry

Science.gov (United States)

Liu, Chengyuan; Zhu, Yanan; Yang, Jiuzhong; Zhao, Wan; Lu, Deen; Pan, Yang

2017-04-01

Solvent and ion source pressure were two important factors relating to the photon induced ion-molecule reactions in low pressure photoionization (LPPI). In this work, four anabolic steroids were analyzed by LPPI mass spectrometry. Both the ion species present and their relative abundances could be controlled by switching the solvent and adjusting the ion source pressure. Whereas M•+, MH+, [M - H2O]+, and solvent adducts were observed in positive LPPI, [M - H]- and various oxidation products were abundant in negative LPPI. Changing the solvent greatly affected formation of the ion species in both positive and negative ion modes. The ion intensities of the solvent adduct and oxygen adduct were selectively enhanced when the ion source pressure was elevated from 68 to 800 Pa. The limit of detection could be decreased by increasing the ion source pressure.

Effect of metal ions on the growth and metabolites production of ...

African Journals Online (AJOL)

Effect of metal ions on the growth and metabolites production of Ganoderma lucidum in submerged culture. YH Cui, KC Zhang. Abstract. The effects of several metal ions on the cell growth, production of polysaccharides by Ganoderma lucidum in submerged fermentation were studied. The results showed that 50 ppm Se2+ ...

Atomic x-ray production by relativistic heavy ions

International Nuclear Information System (INIS)

Ioannou, J.G.

1977-12-01

The interaction of heavy ion projectiles with the electrons of target atoms gives rise to the production, in the target, of K-, L- or higher shell vacancies which are in turn followed by the emission of characteristic x-rays. The calculation of the theoretical value of the K- and L-shells vacancy production cross section was carried out for heavy ion projectiles of any energy. The transverse component of the cross section is calculated for the first time in detail and extensive tables of its numerical value as a function of its parameters are also given. Experimental work for 4.88 GeV protons and 3 GeV carbon ions is described. The K vacancy cross section has been measured for a variety of targets from Ti to U. The agreement between the theoretical predictions and experimental results for the 4.88 GeV protons is rather satisfactory. For the 3 GeV carbon ions, however, it is observed that the deviation of the theoretical and experimental values of the K vacancy production becomes larger with the heavier target element. Consequently, the simple scaling law of Z 1 2 for the cross section of the heavy ion with atomic number Z 1 to the proton cross section is not true, for the K-shell at least. A dependence on the atomic number Z 2 of the target of the form (Z 1 - αZ 2 ) 2 , instead of Z 1 2 , is found to give extremely good agreement between theory and experiment. Although the exact physical meaning of such dependence is not yet clearly understood, it is believed to be indicative of some sort of screening effect of the incoming fast projectile by the fast moving in Bohr orbits K-shell electrons of the target. The enhancement of the K-shell ionization cross section by relativistic heavy ions on heavy targets is also discussed in terms of its practical applications in various branches of science and technology

Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

Science.gov (United States)

Zhao, H. W.; Sun, L. T.; Guo, J. W.; Lu, W.; Xie, D. Z.; Hitz, D.; Zhang, X. Z.; Yang, Y.

2017-09-01

The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24-28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of 40Ar+ and 129Xe26+ have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL), China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24 +18 GHz ) heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

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

Production of rare-earth atomic negative ion beams in a cesium-sputter-type negative ion source

International Nuclear Information System (INIS)

Davis, V.T.; Covington, A.M.; Duvvuri, S.S.; Kraus, R.G.; Emmons, E.D.; Kvale, T.J.; Thompson, J.S.

2007-01-01

The desire to study negative ion structure and negative ion-photon interactions has spurred the development of ion sources for use in research and industry. The many different types of negative ion sources available today differ in their characteristics and abilities to produce anions of various species. Thus the importance of choosing the correct type of negative ion source for a particular research or industrial application is clear. In this study, the results of an investigation on the production of beams composed of negatively-charged rare-earth ions from a cylindrical-cathode-geometry, cesium-sputter-type negative ion source are presented. Beams of atomic anions have been observed for most of the first-row rare-earth elements, with typical currents ranging from hundreds of picoamps to several nanoamps

Structural characterization of phospholipids by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry.

Science.gov (United States)

Marto, J A; White, F M; Seldomridge, S; Marshall, A G

1995-11-01

Matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance mass spectrometry provides for structural analysis of the principal biological phospholipids: glycerophosphatidylcholine, -ethanolamine, -serine, and -inositol. Both positive and negative molecular or quasimolecular ions are generated in high abundance. Isolated molecular ions may be collisionally activated in the source side of a dual trap mass analyzer, yielding fragments serving to identify the polar head group (positive ion mode) and fatty acid side chains (negative ion mode). Azimuthal quadrupolar excitation following collisionally activated dissociation refocuses productions close to the solenoid axis; subsequent transfer of product ions to the analyzer ion trap allows for high-resolution mass analysis. Cyro-cooling of the sample probe with liquid nitrogen greatly reduces matrix adduction encountered in the negative ion mode.

Production of multicharged radioactive ion beams for spiral: studies and realization of the first target-ion source system

International Nuclear Information System (INIS)

Maunoury, L.

1998-01-01

In the framework of the SPIRAL project, which concerns the production and the acceleration of a multicharged radioactive ions beam, the following part has been studied: production and ionization of the radioactive ions beam. A first target-source (nanogan II), devoted exclusively to the production of multicharged radioactive ions gas type beams, has been studied and tested. The diffusion efficiency has been deduced from the diffusion equations (Fick laws). This efficiency is governed by the following parameters: the temperature, the grains size of the target, the Arrhenius parameters and the radioactive period. Another study concerning the production targets is presented. It deals with the temperature distribution allowing an utilization of more than one month at a temperature of 2400 K. Another development (SPIRAL II) is devoted to the production of high neutron content radioactive atoms created by the uranium fission, from fast neutrons. The neutrons beam is produced by the ''stripping break-up'' of a deutons beam in a converter. (A.L.B.)

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)

Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

Directory of Open Access Journals (Sweden)

H. W. Zhao

2017-09-01

Full Text Available The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24–28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of ^{40}Ar^{12+} and ^{129}Xe^{26+} have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL, China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24+18  GHz heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

Secondary production and zooplankton abundance in the coastal waters from Vengurla to Malpe, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Goswami, S.C.

Secondary production and zooplankton abundance in surface and vertical hauls at different stations along 7 transects from Vengurla to Malpe, Maharashtra, India were studied. Zooplankton production varied with the depth of sampling station and type...

Constituent quarks and charge particle production in heavy-ion collisions

International Nuclear Information System (INIS)

Mishra, Aditya Nath; Mazumder, Rakesh; Sahoo, Raghunath; Nandi, Basanta Kumar

2012-01-01

Relativistic heavy-ion collisions aims at producing a state of matter which is governed by partonic degree of freedom. The pseudorapidity density of particle multiplicity and transverse energy are the key observables which provide the properties of matter produced in heavy-ion collisions. Study of their dependence on centrality and collision energy is of paramount importance to understand the particle production mechanism. This may provide insight into the partonic phase that might be created in nuclear collisions. Here, in a constituent quarks framework, charged particle and transverse energy production in heavy-ion collisions are studied both as a function of centrality and collision energy, and hence the study gives a prediction for Pb + Pb collisions

Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

Directory of Open Access Journals (Sweden)

Ryo eNakabayashi

2015-12-01

Full Text Available In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis. To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs. The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis.

Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

Science.gov (United States)

Nakabayashi, Ryo; Tsugawa, Hiroshi; Kitajima, Mariko; Takayama, Hiromitsu; Saito, Kazuki

2015-01-01

In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS) is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis). To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs). The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine) and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline) identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis. PMID:26734034

The composition of heavy ions in solar energetic particle events

International Nuclear Information System (INIS)

Fan, C.Y.

1984-01-01

The composition within individual SEP events may vary both with time and energy, and will in general be different from that in other SEP events. Average values of relative abundances measured in a large number of SEP events, however, are found to be roughly energy independent in the proportional1 to proportional20 MeV per nucleon range, and show a systematic deviation from photospheric abundances which seems to be organized in terms of the first ionization potential of the ion. Direct measurements of the charge states of SEPs have revealed the surprisingly common presence of energetic He + along with heavy ions with typically coronal ionization states. High-resolution measurements of isotopic abundance ratios in a small number of SEP events show these to be consistent with the universal composition except for the puzzling overabundance of the SEP 22 Ne/ 20 Ne relative to this isotopes ratio in the solar wind. The broad spectrum of observed elemental abundance variations, which in their extreme result in composition anomalies characteristic of 3 He-rich, heavy-ion rich and carbon-poor SEP events, along with direct measurements of the ionization states of SEPs provide essential information on the physical characteristics of, and conditions in the source regions, as well as important constraints to possible models for SEP production. (orig./HM)

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.)

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

The production and destruction of negative ions

International Nuclear Information System (INIS)

Pegg, D.J.

1991-01-01

During the present grant period we are continuing our measurements of cross sections and asymmetry parameters for single photon-single electron detachment from atomic negative ions. In this period we have studied the stable ions B - and Li - . As a by product of these measurements we have investigated a new technique for measuring electron affinities. As in our previous work, we have made energy- and angle-resolved spectroscopic measurements of the yields and angular distributions of photoelectrons ejected at the intersection of perpendicularly crossed laser and negative ion beams. A combination of measurements of photoelectron yields, which are proportional to differential cross sections, and angular distributions allow us to determine angle-integrated cross sections for the photodetachment process. Cross sections for the inverse process of radiative attachment can be obtained from the photodetachment data by applying the principle of detailed balance

Recording of heavy ion tracks in silicates. Application to the determination of the abundance of ultra-heavy elements in old solar cosmic radiation

International Nuclear Information System (INIS)

Duraud, J.-P.

1978-12-01

The aim of this thesis is to determine the abundance A(Z) and energy spectrum of the elements of atomic number Z present in cosmic radiation, by means of fossil traces recorded in moon and meteorite minerals. The difficulties due amongst other things to natural annealing are examined in detail in part one, of this paper, the outcome being a thorough study of the processes responsible for the formation, chemical attack and annealing of heavy ion tracks. Part two describes an original approach used here and consisting of a combined analysis as a function of annealing for a given track, of the microscopic structure of the latent track and its attack rate. Part three uses the new rules established beforehand to propose a new method of studying the UH ion (Z>30) to VH ion (20 [fr

Evaluating relationships between wild Skeena river sockeye salmon productivity and the abundance of spawning channel enhanced sockeye smolts.

Science.gov (United States)

Price, Michael H H; Connors, Brendan M

2014-01-01

The enhancement of salmon populations has long been used to increase the abundance of salmon returning to spawn and/or to be captured in fisheries. However, in some instances enhancement can have adverse impacts on adjacent non-enhanced populations. In Canada's Skeena watershed, smolt-to-adult survival of Babine Lake sockeye from 1962-2002 was inversely related to the abundance of sockeye smolts leaving Babine Lake. This relationship has led to the concern that Babine Lake smolt production, which is primarily enhanced by spawning channels, may depress wild Skeena (Babine and non-Babine) sockeye populations as a result of increased competition between wild and enhanced sockeye smolts as they leave their natal lakes and co-migrate to sea. To test this hypothesis we used data on Skeena sockeye populations and oceanographic conditions to statistically examine the relationship between Skeena sockeye productivity (adult salmon produced per spawner) and an index of Babine Lake enhanced smolt abundance while accounting for the potential influence of early marine conditions. While we had relatively high power to detect large effects, we did not find support for the hypothesis that the productivity of wild Skeena sockeye is inversely related to the abundance of enhanced sockeye smolts leaving Babine Lake in a given year. Importantly, life-time productivity of Skeena sockeye is only partially explained by marine survival, and likely is an unreliable measure of the influence of smolt abundance. Limitations to our analyses, which include: (1) the reliance upon adult salmon produced per spawner (rather than per smolt) as an index of marine survival, and (2) incomplete age structure for most of the populations considered, highlight uncertainties that should be addressed if understanding relationships between wild and enhanced sockeye is a priority in the Skeena.

Evaluating relationships between wild Skeena river sockeye salmon productivity and the abundance of spawning channel enhanced sockeye smolts.

Directory of Open Access Journals (Sweden)

Michael H H Price

Full Text Available The enhancement of salmon populations has long been used to increase the abundance of salmon returning to spawn and/or to be captured in fisheries. However, in some instances enhancement can have adverse impacts on adjacent non-enhanced populations. In Canada's Skeena watershed, smolt-to-adult survival of Babine Lake sockeye from 1962-2002 was inversely related to the abundance of sockeye smolts leaving Babine Lake. This relationship has led to the concern that Babine Lake smolt production, which is primarily enhanced by spawning channels, may depress wild Skeena (Babine and non-Babine sockeye populations as a result of increased competition between wild and enhanced sockeye smolts as they leave their natal lakes and co-migrate to sea. To test this hypothesis we used data on Skeena sockeye populations and oceanographic conditions to statistically examine the relationship between Skeena sockeye productivity (adult salmon produced per spawner and an index of Babine Lake enhanced smolt abundance while accounting for the potential influence of early marine conditions. While we had relatively high power to detect large effects, we did not find support for the hypothesis that the productivity of wild Skeena sockeye is inversely related to the abundance of enhanced sockeye smolts leaving Babine Lake in a given year. Importantly, life-time productivity of Skeena sockeye is only partially explained by marine survival, and likely is an unreliable measure of the influence of smolt abundance. Limitations to our analyses, which include: (1 the reliance upon adult salmon produced per spawner (rather than per smolt as an index of marine survival, and (2 incomplete age structure for most of the populations considered, highlight uncertainties that should be addressed if understanding relationships between wild and enhanced sockeye is a priority in the Skeena.

High Resolution Separations and Improved Ion Production and Transmission in Metabolomics

Energy Technology Data Exchange (ETDEWEB)

Metz, Thomas O.; Page, Jason S.; Baker, Erin Shammel; Tang, Keqi; Ding, Jie; Shen, Yufeng; Smith, Richard D.

2008-03-31

The goal of metabolomics experiments is the detection and quantitation of as many sample components as reasonably possible in order to identify “features” that can be used to characterize the samples under study. When utilizing electrospray ionization to produce ions for analysis by mass spectrometry (MS), it is imperative that metabolome sample constituents be efficiently separated prior to ion production, in order to minimize the phenomenon of ionization suppression. Similarly, optimization of the MS inlet can lead to increased measurement sensitivity. This review will focus on the role of high resolution liquid chromatography (LC) separations in conjunction with improved ion production and transmission for LC-MS-based metabolomics.

Ion beam production and study of radioactive isotopes with the laser ion source at ISOLDE

Science.gov (United States)

Fedosseev, Valentin; Chrysalidis, Katerina; Day Goodacre, Thomas; Marsh, Bruce; Rothe, Sebastian; Seiffert, Christoph; Wendt, Klaus

2017-08-01

At ISOLDE the majority of radioactive ion beams are produced using the resonance ionization laser ion source (RILIS). This ion source is based on resonant excitation of atomic transitions by wavelength tunable laser radiation. Since its installation at the ISOLDE facility in 1994, the RILIS laser setup has been developed into a versatile remotely operated laser system comprising state-of-the-art solid state and dye lasers capable of generating multiple high quality laser beams at any wavelength in the range of 210-950 nm. A continuous programme of atomic ionization scheme development at CERN and at other laboratories has gradually increased the number of RILIS-ionized elements. At present, isotopes of 40 different elements have been selectively laser-ionized by the ISOLDE RILIS. Studies related to the optimization of the laser-atom interaction environment have yielded new laser ion source types: the laser ion source and trap and the versatile arc discharge and laser ion source. Depending on the specific experimental requirements for beam purity or versatility to switch between different ionization mechanisms, these may offer a favourable alternative to the standard hot metal cavity configuration. In addition to its main purpose of ion beam production, the RILIS is used for laser spectroscopy of radioisotopes. In an ongoing experimental campaign the isotope shifts and hyperfine structure of long isotopic chains have been measured by the extremely sensitive in-source laser spectroscopy method. The studies performed in the lead region were focused on nuclear deformation and shape coexistence effects around the closed proton shell Z = 82. The paper describes the functional principles of the RILIS, the current status of the laser system and demonstrated capabilities for the production of different ion beams including the high-resolution studies of short-lived isotopes and other applications of RILIS lasers for ISOLDE experiments. This article belongs to the Focus on

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.)

Simultaneous quantification of amino acids and Amadori products in foods through ion-pairing liquid chromatography-high-resolution mass spectrometry.

Science.gov (United States)

Troise, Antonio Dario; Fiore, Alberto; Roviello, Giovanni; Monti, Simona Maria; Fogliano, Vincenzo

2015-01-01

The formation of the Amadori products (APs) is the first key step of Maillard reaction. Only few papers have dealt with simultaneous quantitation of amino acids and corresponding APs (1-amino-1-deoxy-2-ketose). Chromatographic separation of APs is affected by several drawbacks mainly related to their poor retention in conventional reversed phase separation. In this paper, a method for the simultaneous quantification of amino acids and their respective APs was developed combining high-resolution mass spectrometry with ion-pairing liquid chromatography. The limit of detection was 0.1 ng/mL for tryptophan, valine and arginine, while the limit of quantification ranged from 2 to 5 ng/mL according to the specific sensitivity of each analyte. The relative standard deviation % was lower than 10 % and the coefficient of correlation was higher than 0.99 for each calibration curve. The method was applied to milk, milk-based products, raw and processed tomato. Among the analyzed products, the most abundant amino acid was glutamic acid (16,646.89 ± 1,385.40 µg/g) and the most abundant AP was fructosyl-arginine in tomato puree (774.82 ± 10.01 µg/g). The easiness of sample preparation coupled to the analytical performances of the proposed method introduced the possibility to use the pattern of free amino acids and corresponding APs in the evaluation of the quality of raw food as well as the extent of thermal treatments in different food products.

Transfer products from the reactions of heavy ions with heavy nuclei

International Nuclear Information System (INIS)

Thomas, K.E. III.

1979-11-01

Production of nuclides heavier than the target from 86 Kr- and 136 Xe-induced reactions with 181 Ta and 238 U was investigated. Attempts were made to produce new neutron-excess Np and Pu isotopes by the deep inelastic mechanism. No evidence was found for 242 Np or 247 Pu. Estimates were made for the production of 242 Np, 247 Pu, and 248 Am from heavy-ion reactions with uranium targets. Comparisons of reactions of 86 Kr and 136 Xe ions with thick 181 Ta targets and 86 Kr, 136 Xe and 238 U ions with thick 238 U targets indicate that the most probable products are not dependent on the projectile. The most probable products can be predicted by the equation Z - Z/sub target/ = 0.43 (A - A/sub target/) + 1.0. The major effect of the projectile is the magnitude of the production cross section of the heavy products. Based on these results, estimates are made of the most probable mass of element 114 produced from heavy-ion reactions with 248 Cm and 254 Es targets. These estimates give the mass number of element 114 as approx. 287 if produced in heavy-ion reactions with these very heavy targets. Excitation functions of gold and bismuth isotopes arising from 86 Kr- and 136 Xe-induced reactions with thin 181 Ta targets were measured. These results indicate that the shape and location (in Z and A above the target) of the isotopic distributions are not strongly dependent on the projectile incident energy. Also, the nuclidic cross sections are found to increase with an increase in projectile energy to a maximum at approximately 1.4 to 1.5 times the Coulomb barrier. Above this maximum, the nuclidic cross sections are found to decrease with an increase in projectile energy. This decrease in cross section is believed to be due to fission of the heavy products caused by high excitation energy and angular momentum. 111 references, 39 figures, 34 tables

Bio-Nano ECRIS: An electron cyclotron resonance ion source for new materials production

Energy Technology Data Exchange (ETDEWEB)

Uchida, T. [Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Minezaki, H. [Graduate School of Engineering, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Tanaka, K.; Asaji, T. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama, Toyama 930-1305 (Japan); Muramatsu, M.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem Ter 18/c (Hungary); Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Graduate School of Engineering, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan)

2010-02-15

We developed an electron cyclotron resonance ion source (ECRIS) for new materials production on nanoscale. Our main target is the endohedral fullerenes, which have potential in medical care, biotechnology, and nanotechnology. In particular, iron-encapsulated fullerene can be applied as a contrast material for magnetic resonance imaging or microwave heat therapy. Thus, our new ECRIS is named the Bio-Nano ECRIS. In this article, the recent progress of the development of the Bio-Nano ECRIS is reported: (i) iron ion beam production using induction heating oven and (ii) optimization of singly charged C{sub 60} ion beam production.

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)

Removal of radon decay products with ion generators - comparison of experimental results with theory

International Nuclear Information System (INIS)

Maher, E.F.; Rudnick, S.N.; Moeller, D.W.

1985-01-01

The potential of ion generators to remove radon decay products from the airspace of residences or mines was investigated both experimentally and theoretically. A positive ion generator, producing an air ion current of less than 2 μA and operated in a 78 m 3 chamber with air exchange rates ranging from 0.2 to 0.8-hr -1 and relative humidities ranging from 20 to nearly 100%, reduced the concentrations of airborne radon decay products by as much as 85%. A negative ion generator, operated under the same range of conditions, was less effective, producing airborne radon decay product removals up to 67%. Experimental results compared favorably with a simple theoretical model that hypothesizes a three-part process: 1) radon decay products, as well as aerosol particles to which some of these decay products attach, are charged by diffusion of the air ions produced by the generator; 2) the air ions also produce a nonuniform space charge in the chamber that results in an electric field gradient radially outwards from the generator to the chamber surfaces; and 3) because of the influence of this electric field, the charged decay products and particles migrate toward nearby surfaces where they plate out. The net benefit of unipolar space charging is a substantial decrease in the steady-state radon decay product concentrations in the airspace with a corresponding reduction in the lung dose equivalent to the occupants

High temperature electron beam ion source for the production of single charge ions of most elements of the Periodic Table

CERN Document Server

Panteleev, V N; Barzakh, A E; Fedorov, D V; Ivanov, V S; Moroz, F V; Orlov, S Y; Seliverstov, D M; Stroe, L; Tecchio, L B; Volkov, Y M

2003-01-01

A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 deg. C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1-6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

Forward electron production in heavy ion-atom and ion-solid collisions

International Nuclear Information System (INIS)

Sellin, I.A.

1984-01-01

A sharp cusp in the velocity spectrum of electrons, ejected in ion-atom and ion-solid collisions, is observed when the ejected electron velocity vector v/sub e/ matches that of the emergent ion vector v/sub p/ in both speed and direction. In ion-atom collisions, the electrons originate from capture to low-lying, projectile-centered continuum states (ECC) for fast bare or nearly bare projectiles, and from loss to those low-lying continuum states (ELC) when loosely bound projectile electrons are available. Most investigators now agree that ECC cusps are strongly skewed toward lower velocities, and exhibit full widths half maxima roughly proportional to v/sub p/ (neglecting target-shell effects, which are sometimes strong). A close examination of recent ELC data shows that ELC cusps are instead nearly symmetric, with widths nearly independent on v/sub p/ in the velocity range 6 to 18 a.u., a result only recently predicted by theory. Convoy electron cusps produced in heavy ion-solid collisions at MeV/u energies exhibit approximately velocity-independent widths very similar to ELC cusp widths. While the shape of the convoy peaks is approximately independent of projectile Z, velocity, and of target material, it is found that the yields in polycrystalline targets exhibit a strong dependence on projectile Z and velocity. While attempts have been made to link convoy electron production to binary ECC or ELC processes, sometimes at the last layer, or alternatively to a solid-state wake-riding model, our measured dependences of cusp shape and yield on projectile charge state and energy are inconsistent with the predictions of available theories. 10 references, 8 figures, 1 table

Application of Liquid Chromatography/Ion Trap Mass Spectrometry Technique to Determine Ergot Alkaloids in Grain Products.

Science.gov (United States)

Bryła, Marcin; Szymczyk, Krystyna; Jędrzejczak, Renata; Roszko, Marek

2015-03-01

A liquid chromatography/ion trap mass spectrometry-based method to determine six ergot alkaloids and their isomers is presented. The samples were cleaned on neutral alumina-based solid-phase extraction cartridges. The following method parameters were obtained (depending on the analyte and spiking level): method recovery from 63.0 to 104.6%, relative standard deviation below 18%, linear range from 1 to 325 µg/kg, linear correlation coefficient not less than 0.98. The developed analytical procedure was applied to determine the levels of ergot alkaloids in 65 samples of selected rye-based food products (flour - 34 samples, bran - 12 samples, rye - 18 samples, flakes - 1 sample). Measurable levels of alkaloids were found in majority of the analysed samples, particularly in rye flour. Additionally, alkaloids were determined in ergot sclerotia isolated from rye grains. Total content was nearly 0.01% (97.9 mg/kg). However, the alkaloid profile was dominated by ergocristine at 45.6% (44.7 mg/kg), an alkaloid not commonly found in the tested food products. Ergocorninine at 0.2% (0.2 mg/kg) was the least abundant alkaloid.

Measurement of quarkonia production in heavy-ion collisions with the ATLAS detector

CERN Document Server

Tapia Araya, Sebastian; The ATLAS collaboration

2017-01-01

The suppression of heavy quarkonia states in heavy-ion collisions is a phenomenon understood as a consequence of QGP formation in the hot, dense system formed in heavy-ion collisions at the LHC. In addition to hot matter effects in heavy-ion collisions , cold nuclear effects may also affect quarkonia production . Therefore, a full assessment requires detailed studies on the effects present in both A-A and p+A collisions. Based on p+Pb data collected in 2013 and pp and Pb+Pb data collected in 2015 at the LHC, the ATLAS experiment has studied prompt and non-prompt J/psi and psi(2S) productions as well as Upsilon production via the di-muon decay final states. The results are of the various measurements are discussed.

Measurement of quarkonia production in heavy-ion collisions with the ATLAS detector

CERN Document Server

Kremer, Jakub Andrzej; The ATLAS collaboration

2017-01-01

The suppression of heavy quarkonia states in heavy-ion collisions is a phenomenon understood as a consequence of QGP formation in the hot, dense system formed in heavy-ion collisions at the LHC. In addition to hot matter effects in heavy-ion collisions, cold nuclear effects may also affect quarkonia production. Therefore, a full assessment requires detailed studies on the effects present in both A-A and p+A collisions. Based on p+Pb data collected in 2013 and pp and Pb+Pb data collected in 2015 at the LHC, the ATLAS experiment has studied prompt and non-prompt J/psi and psi(2S) productions as well as Upsilon production via the di-muon decay final states. The results of the various measurements are discussed

Quantum signature in heavy-ion pion production

International Nuclear Information System (INIS)

Buvel, R.L.

1985-01-01

A revised model for pion production in heavy-ion peripheral collisions is presented. The pion-production mechanism investigated here is a two step process involving the formation and subsequent decay of an isobar resonance in the projectile nucleus. The independent-particle shell model with harmonic oscillator states is used to approximate the internal structure of the nucleus. The inclusion of the internal structure of the projectile nucleus led to the discovery of a quantum signature in the pion-production differential cross section. The quantum signature involves a matching condition where the pion-production differential cross section goes to zero for a particular value of the pion kinetic energy. The theory is compared to a recent experiment, but the results of this comparison are inconclusive

The MOSDEF Survey: Direct Observational Constraints on the Ionizing Photon Production Efficiency, ξ ion, at z ∼ 2

Science.gov (United States)

Shivaei, Irene; Reddy, Naveen A.; Siana, Brian; Shapley, Alice E.; Kriek, Mariska; Mobasher, Bahram; Freeman, William R.; Sanders, Ryan L.; Coil, Alison L.; Price, Sedona H.; Fetherolf, Tara; Azadi, Mojegan; Leung, Gene; Zick, Tom

2018-03-01

We combine Hα and Hβ spectroscopic measurements and UV photometry for a sample of 673 galaxies from the MOSDEF survey to constrain hydrogen-ionizing photon production efficiencies ({ξ }ion}) at z = 1.4–2.6. We find = 25.06 (25.34), assuming the Calzetti (SMC) curve for the UV dust correction and a scatter of 0.28 dex in the {ξ }ion} distribution. After accounting for observational uncertainties and variations in dust attenuation, we conclude that the remaining scatter in {ξ }ion} is likely dominated by galaxy-to-galaxy variations in stellar populations, including the slope and upper-mass cutoff of the initial mass function, stellar metallicity, star formation burstiness, and stellar evolution (e.g., single/binary star evolution). Moreover, {ξ }ion} is elevated in galaxies with high ionization states (high [O III]/[O II]) and low oxygen abundances (low [N II]/Hα and high [O III]/Hβ) in the ionized ISM. However, {ξ }ion} does not correlate with the offset from the z ∼ 0 star-forming locus in the BPT diagram, suggesting no change in the hardness of the ionizing radiation accompanying the offset from the z ∼ 0 sequence. We also find that galaxies with blue UV spectral slopes ( =-2.1) have {ξ }ion} elevated by a factor of ∼2 relative to the average {ξ }ion} of the sample ( =-1.4). If these blue galaxies are similar to those at z > 6, our results suggest that a lower Lyman-continuum escape fraction is required for galaxies to maintain reionization, compared to the canonical {ξ }ion} predictions from stellar population models. Furthermore, we demonstrate that even with robustly dust-corrected Hα, the UV dust attenuation can cause on average a ∼0.3 dex systematic uncertainty in {ξ }ion} calculations.

Charged fusion product and fast ion loss in TFTR

International Nuclear Information System (INIS)

Zweben, S.J.; Darrow, D.S.; Fredrickson, E.D.; Mynick, H.E.; White, R.B.; Biglari, H.; Bretz, N.; Budny, R.; Bush, C.E.; Chang, C.S.; Chen, L.; Cheng, C.Z.; Fu, G.Y.; Hammett, G.W.; Hawryluk, R.J.; Hosea, J.; Johnson, L.; Mansfield, D.; McGuire, K.; Medley, S.S.; Nazikian, R.; Owens, D.K.; Park, H.; Park, J.; Phillips, C.K.; Schivell, J.; Stratton, B.C.; Ulrickson, M.; Wilson, R.; Young, K.M.; Fisher, R.; McChesney, J.; Fonck, R.; McKee, G.; Tuszewski, M.

1993-03-01

Several different fusion product and fast ion loss processes have been observed in TFTR using an array of pitch angle, energy and time resolved scintillator detectors located near the vessel wall. For D-D fusion products (3 MeV protons and 1 MeV tritons) the observed loss is generally consistent with expected first-orbit loss for Ip I MA. However, at higher currents, Ip = 1.4--2.5 MA, an NM induced D-D fusion product loss can be up to 3-4 times larger than the first-orbit loss, particularly at high beam powers, P ≥ 25 MW. The MHD induced loss of 100 KeV neutron beam ions and ∼0.5 MeV ICRF minority tail tons has also been measured ≤ 459 below the outer midplane. be potential implications of these results for D-T alpha particle experiments in TFTR and ITER are described

Abundances in field dwarf stars. II. Carbon and nitrogen abundances

Energy Technology Data Exchange (ETDEWEB)

Laird, J.B.

1985-02-15

Intermediate-dispersion spectra of 116 field dwarf stars, plus 10 faint field giants and 3 Hyades dwarfs, have been used to derive carbon and nitrogen abundances relative to iron. The program sample includes both disk and halo stars, spanning a range in (Fe/H) of +0.50 to -2.45. Synthetic spectra of CH and NH bands have been used to determine carbon and nitrogen abundances. The C/Fe ratio is solar over the range of metallicity studied, with an estimated intrinsic scatter of 0.10 dex. Down to (Fe/H)roughly-equal-1.8, below which the nitrogen abundance could not be measured, the N/Fe ratio is also constant for the majority of stars, indicating that nitrogen production is largely primary. Four halo stars are found to be enhanced in nitrogen relative to iron, by factors between 5 and 50, although their carbon abundances appear to be normal. These results are discussed in connection with the chemical evolution of the Galaxy and the sites of C, N, and Fe nucleosynthesis. The results require that C, N, and Fe be produced in stars of similar mass. Our current understanding of N production, then, implies that most Type I supernovae have intermediate-mass progenitors. The nitrogen in the N-enhanced halo stars is very probably primordial, indicating that the interstellar medium at early epochs contained substantial inhomogeneities.

Abundances in field dwarf stars. II. Carbon and nitrogen abundances

International Nuclear Information System (INIS)

Laird, J.B.

1985-01-01

Intermediate-dispersion spectra of 116 field dwarf stars, plus 10 faint field giants and 3 Hyades dwarfs, have been used to derive carbon and nitrogen abundances relative to iron. The program sample includes both disk and halo stars, spanning a range in [Fe/H] of +0.50 to -2.45. Synthetic spectra of CH and NH bands have been used to determine carbon and nitrogen abundances. The C/Fe ratio is solar over the range of metallicity studied, with an estimated intrinsic scatter of 0.10 dex. Down to [Fe/H]roughly-equal-1.8, below which the nitrogen abundance could not be measured, the N/Fe ratio is also constant for the majority of stars, indicating that nitrogen production is largely primary. Four halo stars are found to be enhanced in nitrogen relative to iron, by factors between 5 and 50, although their carbon abundances appear to be normal. These results are discussed in connection with the chemical evolution of the Galaxy and the sites of C, N, and Fe nucleosynthesis. The results require that C, N, and Fe be produced in stars of similar mass. Our current understanding of N production, then, implies that most Type I supernovae have intermediate-mass progenitors. The nitrogen in the N-enhanced halo stars is very probably primordial, indicating that the interstellar medium at early epochs contained substantial inhomogeneities

IDENTIFICATION OF DEGRADATION PRODUCTS OF SOME CHEMICAL WARFARE AGENTS BY CAPILLARY ELECTROPHORESIS IONSPRAY MASS-SPECTROMETRY

NARCIS (Netherlands)

KOSTIAINEN, R; BRUINS, AP; HAKKINEN, VMA

1993-01-01

Capillary zone electrophoresis-ionspray mass spectrometry (CZE-IS-MS) in the negative-ion mode was applied in the identification of five organophosphonic acids, which are the primary hydrolysis products of nerve agents. The spectra exhibit a very abundant (M - H)- ion with minimal fragmentation.

Role of positive ions on the surface production of negative ions in a fusion plasma reactor type negative ion source--Insights from a three dimensional particle-in-cell Monte Carlo collisions model

Science.gov (United States)

Fubiani, G.; Boeuf, J. P.

2013-11-01

Results from a 3D self-consistent Particle-In-Cell Monte Carlo Collisions (PIC MCC) model of a high power fusion-type negative ion source are presented for the first time. The model is used to calculate the plasma characteristics of the ITER prototype BATMAN ion source developed in Garching. Special emphasis is put on the production of negative ions on the plasma grid surface. The question of the relative roles of the impact of neutral hydrogen atoms and positive ions on the cesiated grid surface has attracted much attention recently and the 3D PIC MCC model is used to address this question. The results show that the production of negative ions by positive ion impact on the plasma grid is small with respect to the production by atomic hydrogen or deuterium bombardment (less than 10%).

Role of positive ions on the surface production of negative ions in a fusion plasma reactor type negative ion source—Insights from a three dimensional particle-in-cell Monte Carlo collisions model

International Nuclear Information System (INIS)

Fubiani, G.; Boeuf, J. P.

2013-01-01

Results from a 3D self-consistent Particle-In-Cell Monte Carlo Collisions (PIC MCC) model of a high power fusion-type negative ion source are presented for the first time. The model is used to calculate the plasma characteristics of the ITER prototype BATMAN ion source developed in Garching. Special emphasis is put on the production of negative ions on the plasma grid surface. The question of the relative roles of the impact of neutral hydrogen atoms and positive ions on the cesiated grid surface has attracted much attention recently and the 3D PIC MCC model is used to address this question. The results show that the production of negative ions by positive ion impact on the plasma grid is small with respect to the production by atomic hydrogen or deuterium bombardment (less than 10%)

Qualitative and quantitative characterization of plasma proteins when incorporating traveling wave ion mobility into a liquid chromatography-mass spectrometry workflow for biomarker discovery: use of product ion quantitation as an alternative data analysis tool for label free quantitation.

Science.gov (United States)

Daly, Charlotte E; Ng, Leong L; Hakimi, Amirmansoor; Willingale, Richard; Jones, Donald J L

2014-02-18

Discovery of protein biomarkers in clinical samples necessitates significant prefractionation prior to liquid chromatography-mass spectrometry (LC-MS) analysis. Integrating traveling wave ion mobility spectrometry (TWIMS) enables in-line gas phase separation which when coupled with nanoflow liquid chromatography and data independent acquisition tandem mass spectrometry, confers significant advantages to the discovery of protein biomarkers by improving separation and inherent sensitivity. Incorporation of TWIMS leads to a packet of concentrated ions which ultimately provides a significant improvement in sensitivity. As a consequence of ion packeting, when present at high concentrations, accurate quantitation of proteins can be affected due to detector saturation effects. Human plasma was analyzed in triplicate using liquid-chromatography data independent acquisition mass spectrometry (LC-DIA-MS) and using liquid-chromatography ion-mobility data independent acquisition mass spectrometry (LC-IM-DIA-MS). The inclusion of TWIMS was assessed for the effect on sample throughput, data integrity, confidence of protein and peptide identification, and dynamic range. The number of identified proteins is significantly increased by an average of 84% while both the precursor and product mass accuracies are maintained between the modalities. Sample dynamic range is also maintained while quantitation is achieved for all but the most abundant proteins by incorporating a novel data interpretation method that allows accurate quantitation to occur. This additional separation is all achieved within a workflow with no discernible deleterious effect on throughput. Consequently, TWIMS greatly enhances proteome coverage and can be reliably used for quantification when using an alternative product ion quantification strategy. Using TWIMS in biomarker discovery in human plasma is thus recommended.

Productive diversification in natural resource abundant countries : limitations, policies and the experience of Argentina in the 2000s

NARCIS (Netherlands)

L.A. Serino (Leandro)

2009-01-01

textabstractThe debate on the pattern of specialization in natural resource abundant countries has re-emerged as demand for raw materials and food products from the rapidly growing East Asian countries, speculation in financial markets, and changes in production techniques augmented the

Influence of the nuclear autocorrelation function on the positron production in heavy-ion collisions

International Nuclear Information System (INIS)

Tomoda, T.; Weidenmueller, H.A.

1983-01-01

The influence of a nuclear reaction on atomic positron production in heavy-ion collisions is investigated. Using statistical concepts, we describe the nuclear S matrix for a heavy-ion induced reaction as a statistically fluctuating function of energy. The positron production rate is then dependent on the autocorrelation function of this S matrix, and on the ratio of the ''direct'' versus the ''fluctuating'' part of the nuclear cross section. Numerical calculations show that in this way, current experimental results on positron production in heavy-ion collisions can be reproduced in a semiquantitative fashion

Tuning Li2MO3 phase abundance and suppressing migration of transition metal ions to improve the overall performance of Li- and Mn-rich layered oxide cathode

Science.gov (United States)

Zhang, Shiming; Tang, Tian; Ma, Zhihua; Gu, Haitao; Du, Wubing; Gao, Mingxia; Liu, Yongfeng; Jian, Dechao; Pan, Hongge

2018-03-01

The poor cycling stability of Li- and Mn-rich layered oxide cathodes used in lithium-ion batteries (LIBs) has severely limited their practical application. Unfortunately, current strategies to improve their lifecycle sacrifice initial capacity. In this paper, we firstly report the synergistic improvement of the electrochemical performance of a Li1.2Ni0.13Co0.13Mn0.54O2 (LNCMO) cathode material, including gains for capacity, cycling stability, and rate capability, by the partial substitution of Li+ ions by Mg2+ ions. Electrochemical performance is evaluated by a galvanostatic charge and discharge test and electrochemical impedance spectroscopy (EIS). Structure and morphology are characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Compared with the substitution of transition metal (TM) ions with Mg2+ ions reported previously, the substitution of Li+ ions by Mg2+ ions not only drastically ameliorates the capacity retention and rate performance challenges of LNCMO cathodes but also markedly suppresses their voltage fading, due to the inhibition of the migration of TM ions during cycling, while also increasing the capacity of the cathode due to an increased abundance of the Li2MO3 phase.

Quality or quantity: is nutrient transfer driven more by symbiont identity and productivity than by symbiont abundance?

Science.gov (United States)

Freeman, Christopher J; Thacker, Robert W; Baker, David M; Fogel, Marilyn L

2013-06-01

By forming symbiotic interactions with microbes, many animals and plants gain access to the products of novel metabolic pathways. We investigated the transfer of symbiont-derived carbon and nitrogen to the sponges Aplysina cauliformis, Aplysina fulva, Chondrilla caribensis, Neopetrosia subtriangularis and Xestospongia bocatorensis, all of which host abundant microbial populations, and Niphates erecta, which hosts a sparse symbiont community. We incubated sponges in light and dark bottles containing seawater spiked with (13)C- and (15)N-enriched inorganic compounds and then measured (13)C and (15)N enrichment in the microbial (nutrient assimilation) and sponge (nutrient transfer) fractions. Surprisingly, although most sponges hosting abundant microbial communities were more enriched in (13)C than N. erecta, only N. subtriangularis was more enriched in (15)N than N. erecta. Although photosymbiont abundance varied substantially across species, (13)C and (15)N enrichment was not significantly correlated with photosymbiont abundance. Enrichment was significantly correlated with the ratio of gross productivity to respiration (P:R), which varied across host species and symbiont phylotype. Because irradiance impacts P:R ratios, we also incubated A. cauliformis in (13)C-enriched seawater under different irradiances to determine whether symbiont carbon fixation and transfer are dependent on irradiance. Carbon fixation and transfer to the sponge host occurred in all treatments, but was greatest at higher irradiances and was significantly correlated with P:R ratios. Taken together, these results demonstrate that nutrient transfer from microbial symbionts to host sponges is influenced more by host-symbiont identities and P:R ratios than by symbiont abundance.

Numerical study of cesium effects on negative ion production in volume sources

Energy Technology Data Exchange (ETDEWEB)

Fukumasa, Osamu; Niitani, Eiji [Yamaguchi Univ., Ube (Japan). Faculty of Engineering

1997-02-01

Effects of cesium vapor injection of H{sup -} production in a tandem negative ion source are studied numerically as a function of plasma parameters. Model calculation is done by solving a set of particle balance equations in a steady-state hydrogen discharge plasmas. Here, the results which focus on gas pressure and electron temperature dependences of H{sup -} volume production are presented and discussed. With including H{sup -} surface production processes caused by both H atoms and positive hydrogen ions, enhancement of H{sup -} production and pressure dependence of H{sup -} production observed experimentally are well reproduced in the model. To enhance H{sup -} production, however, so-called electron cooling is not so effective if plasma parameters are initially optimized with the use of magnetic filter. (author)

Numerical study of cesium effects on negative ion production in volume H-and D- ion sources

International Nuclear Information System (INIS)

Fukumasa, Osamu; Niitani, Eiji; Yoshino, Kyougo

1997-01-01

We present the results of model calculation on H - /D - isotope effects in the tandem volume source. The model includes the surface production due to cesium injection. On the electron density n e dependence of H - /D - production, we have observed an interesting phenomena. Namely D - production, i.e D - density, is higher than H - production in low n e , but in high n e H - production is higher than D - production. The atomic density plays an important role in the density inversion between H - and D - ions. (author)

Electromagnetic heavy-lepton pair production in relativistic heavy-ion collisions

Energy Technology Data Exchange (ETDEWEB)

Senguel, M.Y. [Atakent Mahallesi, 3. Etap, Halkali-Kuecuekcekmece, Istanbul (Turkey); Gueclue, M.C.; Mercan, Oe.; Karakus, N.G. [istanbul Technical University, Faculty of Science and Letters, Istanbul (Turkey)

2016-08-15

We calculate the cross sections of electromagnetic productions of muon- and tauon-pair productions from the ultra-relativistic heavy ion collisions. Since the Compton wavelengths of muon and tauon are comparable to the radius of the colliding ions, nuclear form factors play important roles for calculating the cross sections. Recent measurement (Abrahamyan et al., Phys Rev Lett 108:112502, 2012) indicates that the neutrons are differently distributed from the protons; therefore this affects the cross section of the heavy-lepton pair production. In order to see the effects of the neutron distributions in the nucleus, we used analytical expression of the Fourier transforms of the Wood-Saxon distribution. Cross section calculations show that the Wood-Saxon distribution function is more sensitive to the parameter R compared to the parameter a. (orig.)

Latest developments at GANIL for stable and radioactive ion beam production

International Nuclear Information System (INIS)

Jardin, P.; Barue, C.; Bajeat, O.; Canet, C.; Clement, E.; Cornell, J. C.; Delahaye, P.; Dubois, M.; Dupuis, M.; Flambard, J. L.; Fraanberg, H.; Frigot, R.; Leboucher, C.; Lecesne, N.; Lecomte, P.; Leherissier, P.; Lemagnen, F.; Leroy, R.; Maunoury, L.; Mery, A.

2010-01-01

In the frame of the SPIRAL II (Systeme de Production d'Ions Radioactifs Acceleres en Ligne Partie II) project, several developments of stable and radioactive ion production systems have been started up. In parallel, GANIL has the ambition to preserve the existing stable and radioactive beams and also to increase its range by offering new ones. In order to identify the best directions for this development, a new group called GANISOL has been formed. Its preliminary conclusions and the latest developments at GANIL are presented.

Molecular ions in comet tails

International Nuclear Information System (INIS)

Wyckoff, S.; Wehinger, P.A.

1976-01-01

Band intensities of the molecular ions CH + , CO + , N 2 + , and H 2 O + have been determined on an absolute scale from tail spectra of comet Kohoutek (1973f) and comet Bradfield (1974b). Photoionization and photodissociation rates have been computed for CH, CO, and N 2 . Also emission rate excitation g-factors for (1) photoionization plus excitation and (2) resonance fluorescence have been computed for the observed ions. It is shown that resonance fluorescence is the dominant excitation mechanism for observed comet tail ions at rapprox. =1 AU. Band system luminosities and molecular ion abundances within a projected nuclear distance rho 4 km have been determined for CH + , CO + , N 2 + , and H 2 O + in comet Kohoutek, and for H 2 O + in comet Bradfield. Estimates are also given for column densities of all observed ions at rhoapprox. =10 4 km on the tailward side of the coma. The observed H 2 O + column densities were found to be roughly the same in comet Kohoutek and comet Bradfield et equal heliocentric distances, while CO + was found to be approximately 100 times more abundant than H 2 O + , N 2 + , and CH + at rhoapprox. =10 4 km in comet Kohoutek. Finally, the relative abundances of the observed ions and of the presumed parent neutral species are briefly discussed

Abundances in planetary nebulae : Including ISO results

NARCIS (Netherlands)

Pottasch, [No Value; Beintema, DA; Sales, JB; Feibelman, WA; Kwok, S; Dopita, M; Sutherland, R

2003-01-01

The far infrared nebular spectrum provides a valuable complement to the observed lines in other spectral regions. There are several reasons for this, the most important being the large increase in the number of ions observed, and the fact that the abundances found from these lines are relatively

Multicharged heavy ion production process and ion sources in impulse regime allowing the operation of the process

International Nuclear Information System (INIS)

Jacquot, B.

1985-01-01

The present invention is concerned with a production process of multicharged ions of elements choosen in the following group carbon, nitrogen, oxygen, neon and argon in a ion source in impulse regime; the process is characterized in that the gas introduced in the ion souce enclosure is a gas mixture in a non-critical proportion (about 50% in partial pressure) of a first gas choosen among helium, nitrogen and oxygen and a second gas choosen in the group comprising carbon, nitrogen, oxygen, neon and argon. This process allows to grow current intensity of heavy ions more than 10 times. The invention is also concerned with a ion source in impulse regime; it is characterized in that it comprises an enclosure related to two gas entrances, provided with a valve controlled by pressure measurement in the enclosure [fr

Microscopic approach to subthreshold pion production in heavy-ion collisions

International Nuclear Information System (INIS)

Tohyama, M.; Kaps, R.; Masak, D.; Mosel, U.

1985-01-01

A microscopic approach to subthreshold pion production in heavy-ion collisions is proposed, in which the wave function of the nucleon system is approximated in the time-dependent Hartree-Fock theory and an effective interaction for the pion-production process is taken from (p,π) reaction theories. The model is applied to pion production in 16 O + 16 O collisions. (orig.)

Neon Abundances from a Spitzer/IRS Survey of Wolf-Rayet Stars

NARCIS (Netherlands)

Ignace, R.; Cassinelli, J.P.; Tracy, G.; Churchwell, E.B.; Lamers, H.J.G.L.M.

2007-01-01

We report on neon abundances derived from Spitzer high resolution spectral data of eight Wolf-Rayet (WR) stars using the forbidden line of [Ne III] 15.56 μm. Our targets include four WN stars of subtypes 4-7, and four WC stars of subtypes 4-7. We derive ion fraction abundances γ of Ne2+ for the

Gravitationally induced particle production and its impact on the WIMP abundance

Directory of Open Access Journals (Sweden)

I. Baranov

2015-12-01

Full Text Available A large set of independent astronomical observations have provided a strong evidence for nonbaryonic dark matter in the Universe. One of the most investigated candidates is an unknown long-lived Weakly Interacting Massive Particle (WIMP which was in thermal equilibrium with the primeval plasma. Here we investigate the WIMP abundance based on the relativistic kinetic treatment for gravitationally induced particle production recently proposed in the literature (Lima and Baranov, 2014 [16]. The new evolution equation is deduced and solved both numerically and through a semi-analytical approach. The predictions of the WIMP observables are discussed and compared with the ones obtained in the standard approach.

Silicene for Na-ion battery applications

KAUST Repository

Zhu, Jiajie; Schwingenschlö gl, Udo

2016-01-01

Na-ion batteries are promising candidates to replace Li-ion batteries in large scale applications because of the advantages in natural abundance and cost of Na. Silicene has potential as the anode in Li-ion batteries but so far has not received

Fundamental aspects on ion-beam surface modification: defect production and migration processes

International Nuclear Information System (INIS)

Rehn, L.E.; Averback, R.S.; Okamoto, P.R.

1984-09-01

Ion-beam modification of metals is generating increasing scientific interest not only because it has exciting technological potential, but also because it has raised fundamental questions concerning radiation-induced diffusion processes. In addition to the implanted species, several defect production and migration mechanisms contribute to changes in the near-surface composition of an alloy during ion bombardment, e.g., atoms exchange positions via displacements and replacement sequences; preferential sputtering effects arise; radiation-enhanced diffusion and radiation-induced segregation occur. The latter two defect migration mechanisms are of particular significance since they can alter the composition to depths which are much greater than the implanted ion range. By altering various parameters such as irradiation temperature, ion mass, energy, and current density, and initial alloying distributions, a rich variety of near-surface composition profiles can be created. We have utilized changes in ion mass and energy, and irradiation temperature to distinguish defect production from defect migration effects. Experimental results are presented which provide a guide to the relative efficiencies of different mechanisms under various irradiation conditions. 46 references

"Design and application of a data-independent precursor and product ion repository."

NARCIS (Netherlands)

Thalassinos, K.; Vissers, J.P.; Tenzer, S.; Levin, Y.; Thompson, J.W.; Daniel, D.; Mann, D.; Delong, M.R.; Moseley, M.A.; America, A.H.P.; Ottens, A.K.; Cavey, G.S.; Efstathiou, G.; Scrivens, J.H.; Langridge, J.I.; Geromanos, S.J.

2012-01-01

The functional design and application of a data-independent LC-MS precursor and product ion repository for protein identification, quantification, and validation is conceptually described. The ion repository was constructed from the sequence search results of a broad range of discovery experiments

Ion beam system for implanting industrial products of various shapes

International Nuclear Information System (INIS)

Denholm, A.S.; Wittkower, A.

1985-01-01

Implantation of metals and ceramics with ions of nitrogen and other species has improved surface properties such as friction, wear and corrosion in numerous industrial applications. Zymet has built a production machine to take advantage of this process which can implant a 2 x 10 17 ions/cm 2 dose of nitrogen ions into a 20 cm x 20 cm area in about 30 min using a 100 keV beam. Treatment is accomplished by mounting the product on a cooled, tiltable, turntable which rotates continuously, or is indexed in 15 0 steps to expose different surfaces in fixed position. Product cooling is accomplished by using a chilled eutectic metal to mount and grip the variously shaped objects. A high voltage supply capable of 10 mA at 100 kV is used, and the equipment is microcomputer controlled via serial light links. All important machine parameters are presented in sequenced displays on a CRT. Uniformity of treatment and accumulated dose are monitored by a Faraday cup system which provides the microprocessor with data for display of time to completion on the process screen. For routine implants the operator requires only two buttons; one for chamber vacuum control, and the other for process start and stop. (orig.)

Rare earth element abundances in presolar SiC

Science.gov (United States)

Ireland, T. R.; Ávila, J. N.; Lugaro, M.; Cristallo, S.; Holden, P.; Lanc, P.; Nittler, L.; Alexander, C. M. O'D.; Gyngard, F.; Amari, S.

2018-01-01

Individual isotope abundances of Ba, lanthanides of the rare earth element (REE) group, and Hf have been determined in bulk samples of fine-grained silicon carbide (SiC) from the Murchison CM2 chondrite. The analytical protocol involved secondary ion mass spectrometry with combined high mass resolution and energy filtering to exclude REE oxide isobars and Si-C-O clusters from the peaks of interest. Relative sensitivity factors were determined through analysis of NIST SRM reference glasses (610 and 612) as well as a trace-element enriched SiC ceramic. When normalised to chondrite abundances, the presolar SiC REE pattern shows significant deficits at Eu and Yb, which are the most volatile of the REE. The pattern is very similar to that observed for Group III refractory inclusions. The SiC abundances were also normalised to s-process model predictions for the envelope compositions of low-mass (1.5-3 M⊙) AGB stars with close-to-solar metallicities (Z = 0.014 and 0.02). The overall trace element abundances (excluding Eu and Yb) appear consistent with the predicted s-process patterns. The depletions of Eu and Yb suggest that these elements remained in the gas phase during the condensation of SiC. The lack of depletion in some other moderately refractory elements (like Ba), and the presence of volatile elements (e.g. Xe) indicates that these elements were incorporated into SiC by other mechanisms, most likely ion implantation.

Production of intense negative ion beams in magnetically insulated diodes

International Nuclear Information System (INIS)

Lindenbaum, H.

1988-01-01

Production of intense negative ion beams in magnetically insulated diodes was studied in order to develop an understanding of this process by measuring the ion-beam parameters as a function of diode and cathode plasma conditions in different magnetically insulated diodes. A coral diode, a racetrack diode, and an annular diode were used. The UCI APEX pulse line, with a nominal output of 1MV, 140kA, was used under matched conditions with a pulse length of 50 nsec. Negative-ion intensity and divergence were measured with Faraday cups and CR-39 track detectors. Cathode plasma was produced by passive dielectric cathodes and later, by an independent plasma gun. Negative-ion currents had an intensity of a few A/cm 2 with a divergence ranging between a few tenths milliradians for an active TiH 2 plasma gun and 300 milliradians for a passive polyethelene cathode. Negative ions were usually emitted from a few hot spots on the cathode surface. These hot spots are believed to cause transverse electrical fields in the diode gap responsible for the beam divergence. Mass spectrometry measurements showed that the ion beam consists of mainly H - ions when using a polyethelene or a TiH 2 cathodes, and mainly of negative carbon ions when using a carbon cathode

Application of Liquid Chromatography/Ion Trap Mass Spectrometry Technique to Determine Ergot Alkaloids in Grain Products

Directory of Open Access Journals (Sweden)

Krystyna Szymczyk

2015-01-01

Full Text Available A liquid chromatography/ion trap mass spectrometry-based method to determine six ergot alkaloids and their isomers is presented. The samples were cleaned on neutral alumina-based solid-phase extraction cartridges. The following method parameters were obtained (depending on the analyte and spiking level: method recovery from 63.0 to 104.6 %, relative standard deviation below 18 %, linear range from 1 to 325 μg/kg, linear correlation coefficient not less than 0.98. The developed analytical procedure was applied to determine the levels of ergot alkaloids in 65 samples of selected rye-based food products (flour– 34 samples, bran – 12 samples, rye – 18 samples, flakes – 1 sample. Measurable levels of alkaloids were found in majority of the analysed samples, particularly in rye flour. Additionally, alkaloids were determined in ergot sclerotia isolated from rye grains. Total content was nearly 0.01 % (97.9 mg/kg. However, the alkaloid profi le was dominated by ergocristine at 45.6 % (44.7 mg/kg, an alkaloid not commonly found in the tested food products. Ergocorninine at 0.2 % (0.2 mg/kg was the least abundant alkaloid.

Constraints due to the production of radioactive ion beams in the SPIRAL project

International Nuclear Information System (INIS)

Leroy, R.; Huguet, Y.; Jardin, P.; Marry, C.; Pacquet, J.Y.; Villari, A.C.C.

1997-01-01

The radioactive ion beams that will be delivered by the SPIRAL facility will be produced by the interaction of a stable high energy and high intensity primary ion beam delivered by the GANIL cyclotrons with a carbon target heated to 2000 deg C. During this interaction, some radioactive atoms will be created and will diffuse out of the target before entering into an electron cyclotron resonance ion source where they will be ionized and extracted. The production of radioactive ion beams with this method implies high radiation fields that activate and can damage materials located in the neighborhood of the target. Therefore, the production system which is composed of the permanent magnet ECR ion source coupled to a graphite target will be changed after two weeks of irradiation. As this ensemble will be very radioactive, this operation has to be supervised by remote control. The radiation levels around the target-ion source system and a detailed description of the different precautions that have been taken for safety and for prevention of contamination and irradiation are presented. (author)

Heavy ion physics at the LHC

International Nuclear Information System (INIS)

Vogt, R.

2004-01-01

The ion-ion center of mass energies at the LHC will exceed that at RHIC by nearly a factor of 30, providing exciting opportunities for addressing unique physics issues in a completely new energy domain. Some highlights of this new physics domain are presented here. We briefly describe how these collisions will provide new insights into the high density, low momentum gluon content of the nucleus expected to dominate the dynamics of the early state of the system. We then discuss how the dense initial state of the nucleus affects the lifetime and temperature of the produced system. Finally, we explain how the high energy domain of the LHC allows abundant production of ''rare'' processes, hard probes calculable in perturbative quantum chromodynamics, QCD. At the LHC, high momentum jets and b(bar b) bound states, the Υ family, will be produced with high statistics for the first time in heavy ion collisions

Measurement of charmonium production in heavy-ion collisions with the ATLAS detector

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00511724; The ATLAS collaboration

2017-01-01

The suppression of heavy charmonia states in heavy-ion collisions is a phenomenon understood as a consequence of quark gluon plasma formation in the hot, dense system formed in heavy ion collisions at the LHC. In addition to hot matter effects in heavy-ion collisions, cold nuclear effects may also affect heavy charmonia production. Therefore, a full assessment requires detailed studies on the effects present in both A+A and p+A collisions. Based on p+Pb data collected in 2013 and pp and Pb+Pb data collected in 2015 at the LHC, the ATLAS experiment has studied prompt and non-prompt $J/\\psi$ and $\\psi$(2S) productions via the dimuon decay final states. The production and excited-to-ground state ratios of heavy charmonia measured in both p+Pb and Pb+Pb collision data with respect to that measured in pp collision data will be presented in intervals of transverse momentum, rapidity and centrality.

Comments on H- volume production in Cs-seeded ion sources. Appendix I

International Nuclear Information System (INIS)

Peterson, J.R.

1986-01-01

Considerable interest was generated at the IAEA Negative Ion Beam Workshop in Grenoble, France, in March, 1985, by a report from the Kurchatov Institute on the development of a 2-ampere steady-state H - ion source, in which the ions were volume-produced in a discharge in H 2 , seeded with Cs vapor. The mechanism primarily responsible for this remarkably high current from a volume production source was not yet understood, but it was tentatively presumed to involve the collisional energy transfer from electronically excited Cs 6p atoms into H 2 vibrations. In any case, it was apparently different from the surface-plasma interactions that have been assumed to control the H - production in the Dudnikov-Dimov type sources

Mass and angular distributions of the reaction products in heavy ion collisions

Science.gov (United States)

Nasirov, A. K.; Giardina, G.; Mandaglio, G.; Kayumov, B. M.; Tashkhodjaev, R. B.

2018-05-01

The optimal reactions and beam energies leading to synthesize superheavy elements is searched by studying mass and angular distributions of fission-like products in heavy-ion collisions since the evaporation residue cross section consists an ignorable small part of the fusion cross section. The intensity of the yield of fission-like products allows us to estimate the probability of the complete fusion of the interacting nuclei. The overlap of the mass and angular distributions of the fusion-fission and quasifission products causes difficulty at estimation of the correct value of the probability of the compound nucleus formation. A study of the mass and angular distributions of the reaction products is suitable key to understand the interaction mechanism of heavy ion collisions.

Pion production in high energy heavy ion collisions

International Nuclear Information System (INIS)

Wolf, K.L.; Bock, R.; Brockmann, R.

1984-01-01

Experimental data for heavy ion pion production reactions are compared with the predictions of a number of versions of cascade models. Pion suppression effects observed in the experimental data are fit by introducing refinements into cascade theory. Impact parameter adjustment, off-shell effects on the potential and perturbations due to nuclear matter are considered

Phytoplankton abundance and productivity in the vicinity of an operating power plant

International Nuclear Information System (INIS)

Poornima, E.H.; Rajadurai, M.; Venugopalan, V.P.; Narasimhan, S.V.; Rao, V.N.R.

2007-01-01

The impact of power plant operation on the abundance and productivity of phytoplankton was monitored over a period of fifteen months. Field studies showed that in spite of the consistent reduction in phytoplankton biomass and productivity at the Outfall where the heated effluent is discharged, stations close to the mixing point did not show any significant change in phytoplankton biomass or productivity. This suggested that at the Mixing point, mixing of the heated effluents with the ambient seawater was rapid and very extensive, ensuring recovery of phytoplankton biomass and their productivity potential. Field studies during low-dose, shock-dose and no-chlorination suggested that chlorination caused greater damage to phytoplankton chlorophyll than temperature. Laboratory experiments revealed that diatom growth was not much influenced by passage through the condenser cooling system and they were able to grow between 28 deg C and 40 deg C. Short term experiments indicated that chemical stress due to chlorination might be more important than temperature in reducing phytoplankton biomass and productivity. Combined treatment of temperature and chlorine showed little synergistic effect. The data suggest that formulation of condenser discharge criteria of power plants must consider the relative effects of both the stress factors viz., temperature and chlorine. (author)

Paul Trapping of Radioactive 6He+ Ions and Direct Observation of Their β Decay

International Nuclear Information System (INIS)

Flechard, X.; Lienard, E.; Mery, A.; Rodriguez, D.; Ban, G.; Durand, D.; Duval, F.; Herbane, M.; Labalme, M.; Mauger, F.; Naviliat-Cuncic, O.; Velten, Ph.; Thomas, J. C.

2008-01-01

We demonstrate that abundant quantities of short-lived β unstable ions can be trapped in a novel transparent Paul trap and that their decay products can directly be detected in coincidence. Low energy 6 He + (807 ms half-life) ions were extracted from the SPIRAL source at GANIL, then decelerated, cooled, and bunched by means of the buffer gas cooling technique. More than 10 8 ions have been stored over a measuring period of six days, and about 10 5 decay coincidences between the beta particles and the 6 Li ++ recoiling ions have been recorded. The technique can be extended to other short-lived species, opening new possibilities for trap assisted decay experiments

Pilot production of track etch membranes (TEMS) using heavy ion beam scanner

International Nuclear Information System (INIS)

Nair, J.P.; Surendran, P.; Sparrow, Hillary; Ninawe, N.G.; Bhagwat, P.V.; Acharya, N.; Kulshreshta, V.; Rajesh Kumar; Vijay, Y.K.; Kurup, M.B.

2005-01-01

Various methods for making TEMs were conducted at Pelletron Accelerator Facility. The technique for production using ion beam scattering was also established. This is an effort to make TEMs on pilot basis at BARC- TIFR Pelletron Accelerator using Heavy Ion Beam Scanner till large rolling mechanism is implemented

Nonlinear effects in defect production by atomic and molecular ion implantation

International Nuclear Information System (INIS)

David, C.; Dholakia, Manan; Chandra, Sharat; Nair, K. G. M.; Panigrahi, B. K.; Amirthapandian, S.; Amarendra, G.; Varghese Anto, C.; Santhana Raman, P.; Kennedy, John

2015-01-01

This report deals with studies concerning vacancy related defects created in silicon due to implantation of 200 keV per atom aluminium and its molecular ions up to a plurality of 4. The depth profiles of vacancy defects in samples in their as implanted condition are carried out by Doppler broadening spectroscopy using low energy positron beams. In contrast to studies in the literature reporting a progressive increase in damage with plurality, implantation of aluminium atomic and molecular ions up to Al 3 , resulted in production of similar concentration of vacancy defects. However, a drastic increase in vacancy defects is observed due to Al 4 implantation. The observed behavioural trend with respect to plurality has even translated to the number of vacancies locked in vacancy clusters, as determined through gold labelling experiments. The impact of aluminium atomic and molecular ions simulated using MD showed a monotonic increase in production of vacancy defects for cluster sizes up to 4. The trend in damage production with plurality has been explained on the basis of a defect evolution scheme in which for medium defect concentrations, there is a saturation of the as-implanted damage and an increase for higher defect concentrations

The analysis of Rutherford scattering-channelling measurements of disorder production and annealing in ion irradiated semiconductors

International Nuclear Information System (INIS)

Carter, G.; Elliman, R.G.

1983-01-01

Rutherford scattering and channelling of light probe ions (e.g. He + ) has been extensively used for studies of disorder production in ion implanted semiconductors. Various authors have analysed models of amorphousness accumulation and Carter and Webb have indicated the general difficulties in assessing disorder production models from RBS/channelling studies if the production modes are complex and the manner in which the technique responds to different defect structures is unspecified. For less complex disorder production modes and by making reasonable assumptions about the technique response however, some insight into the form of backscattering yield - ion implant fluence functions can be obtained as is discussed in the present communication. It thus becomes possible to infer the importance of different disorder generation processes from RBS/channelling - ion influence studies. It will also be shown how simple annealing processes modify disorder accumulation and thus again how the operation of such processes may be inferred from RBS/channelling - ion fluence measurements. (author)

Dramatic changes in ectomycorrhizal community composition, root tip abundance and mycelial production along a stand-scale nitrogen deposition gradient

DEFF Research Database (Denmark)

Kjøller, Rasmus; Nilsson, Lars Ola; Hansen, Karin

2012-01-01

• Nitrogen (N) availability is known to influence ectomycorrhizal fungal components, such as fungal community composition, biomass of root tips and production of mycelia, but effects have never been demonstrated within the same forest. • We measured concurrently the abundance of ectomycorrhizal...... root tips and the production of external mycelia, and explored the changes in the ectomycorrhizal community composition, across a stand-scale N deposition gradient (from 27 to 43 kg N ha¿¹ yr¿¹) at the edge of a spruce forest. The N status was affected along the gradient as shown by a range of N...... availability indices. • Ectomycorrhizal root tip abundance and mycelial production decreased five and 10-fold, respectively, with increasing N deposition. In addition, the ectomycorrhizal fungal community changed and the species richness decreased. The changes were correlated with the measured indices of N...

Dependence of Au- production upon the target work function in a plasma-sputter-type negative ion source

International Nuclear Information System (INIS)

Okabe, Yushirou; Sasao, Mamiko; Fujita, Junji; Yamaoka, Hitoshi; Wada, Motoi.

1991-01-01

A method to measure the work function of the target surface in a plasma-sputter-type negative ion source has been developed. The method can determine the work function by measuring the photoelectric current induced by two lasers (He-Ne, Ar + laser). The dependence of Au - production upon the work function of the target surface in the ion source was studied using this method. The time variation of the target work function and Au - production rate were measured during the cesium coverage decrease due to the plasma ion sputtering. The observed minimum work function of a cesiated gold surface in an Ar plasma was 1.3 eV. At the same time, the negative ion production rate (Au - current/target current) took the maximum value. The negative ion production rate indicated the same dependence on the incident ion energy as that of the sputtering rate when the work function was constant. (author)

Design and application of a data-independent precursor and product ion repository.

Science.gov (United States)

Thalassinos, Konstantinos; Vissers, Johannes P C; Tenzer, Stefan; Levin, Yishai; Thompson, J Will; Daniel, David; Mann, Darrin; DeLong, Mark R; Moseley, M Arthur; America, Antoine H; Ottens, Andrew K; Cavey, Greg S; Efstathiou, Georgios; Scrivens, James H; Langridge, James I; Geromanos, Scott J

2012-10-01

The functional design and application of a data-independent LC-MS precursor and product ion repository for protein identification, quantification, and validation is conceptually described. The ion repository was constructed from the sequence search results of a broad range of discovery experiments investigating various tissue types of two closely related mammalian species. The relative high degree of similarity in protein complement, ion detection, and peptide and protein identification allows for the analysis of normalized precursor and product ion intensity values, as well as standardized retention times, creating a multidimensional/orthogonal queryable, qualitative, and quantitative space. Peptide ion map selection for identification and quantification is primarily based on replication and limited variation. The information is stored in a relational database and is used to create peptide- and protein-specific fragment ion maps that can be queried in a targeted fashion against the raw or time aligned ion detections. These queries can be conducted either individually or as groups, where the latter affords pathway and molecular machinery analysis of the protein complement. The presented results also suggest that peptide ionization and fragmentation efficiencies are highly conserved between experiments and practically independent of the analyzed biological sample when using similar instrumentation. Moreover, the data illustrate only minor variation in ionization efficiency with amino acid sequence substitutions occurring between species. Finally, the data and the presented results illustrate how LC-MS performance metrics can be extracted and utilized to ensure optimal performance of the employed analytical workflows.

Large-scale production of paper-based Li-ion cells

CERN Document Server

Zolin, Lorenzo

2017-01-01

This book describes in detail the use of natural cellulose fibers for the production of innovative, low-cost, and easily recyclable lithium-ion (Li-ion) cells by means of fast and reliable papermaking procedures that employ water as a solvent. In addition, it proposes specific methods to optimize the safety features of these paper-based cells and to improve the electronic conductivity of the electrodes by means of a carbonization process– an interesting novel technology that enables higher current rate capabilities to be achieved. The in-depth descriptions of materials, methods, and techniques are complemented by the inclusion of a general overview of electrochemical devices and, in particular, of different Li-ion battery configurations. Presenting the outcomes of this important research, the work is of wide interest to electrochemical engineers in both research institutions and industry.

Binary encounter electron production in ion-atom collisions

International Nuclear Information System (INIS)

Grabbe, S.; Bhalla, C.P.; Shingal, R.

1993-01-01

The binary encounter electrons are produced by hard collisions between the target electrons and the energetic projectiles. Richard et al. found the measured double differential cross section for BEe production at zero degree laboratory scattering angle, in collisions of F q+ with H 2 and He targets, to increase as the charge state of the projectile was decreased. The binary encounter electron production has recently been a subject of detailed investigations. We have calculated the differential elastic scattering cross sections of electrons from several ions incorporating the exchange contribution of the continuum and the bound orbitals in addition to the static potential. The double differential binary encounter electron production cross sections are presented using the impulse approximation

μ- and tau-pair production from relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Bottcher, C.; Strayer, M.R.

1986-01-01

The question is addressed of μ- and tau-pair production from the motional Coulomb fields available at the new relativistic heavy-ion accelerators. A semiclassical field theory is developed which is appropriate for families of leptons which are coupled electromagnetically. The field equations are mapped on to a lattice of collocation points using basis spline methods, and techniques for solving the resulting lattice equations are outlined. The properties of the transverse electromagnetic field near the heavy-ion beam are examined and physical arguments are given as to the feasibility of pair creation under a variety of circumstances. Using the Dirac-Hartree equations developed in part one, we shall dynamically evolve the vacuum, using the appropriate fields, and compute μ-pair and tau-pair production cross sections. 16 refs., 10 figs

Ion Mobility Mass Spectrometry Direct Isotope Abundance Analysis

International Nuclear Information System (INIS)

Manard, Manuel J.; Weeks, Stephan; Kyle, Kevin

2010-01-01

The nuclear forensics community is currently engaged in the analysis of illicit nuclear or radioactive material for the purposes of non-proliferations and attribution. One technique commonly employed for gathering nuclear forensics information is isotope analysis. At present, the state-of-the-art methodology for obtaining isotopic distributions is thermal ionization mass spectrometry (TIMS). Although TIMS is highly accurate at determining isotope distributions, the technique requires an elementally pure sample to perform the measurement. The required radiochemical separations give rise to sample preparation times that can be in excess of one to two weeks. Clearly, the nuclear forensics community is in need of instrumentation and methods that can expedite their decision making process in the event of a radiological release or nuclear detonation. Accordingly, we are developing instrumentation that couples a high resolution IM drift cell to the front end of a MS. The IM cell provides a means of separating ions based upon their collision cross-section and mass-to-charge ratio (m/z). Two analytes with the same m/z, but with different collision cross-sections (shapes) would exit the cell at different times, essentially enabling the cell to function in a similar manner to a gas chromatography (GC) column. Thus, molecular and atomic isobaric interferences can be effectively removed from the ion beam. The mobility selected chemical species could then be introduced to a MS for high-resolution mass analysis to generate isotopic distributions of the target analytes. The outcome would be an IM/MS system capable of accurately measuring isotopic distributions while concurrently eliminating isobaric interferences and laboratory radiochemical sample preparation. The overall objective of this project is developing instrumentation and methods to produce near real-time isotope distributions with a modular mass spectrometric system that performs the required gas-phase chemistry and

Application of radioanalytical techniques in the study of the products of heavy-ion reactions

International Nuclear Information System (INIS)

Hoffman, D.C.

1989-01-01

The use of heavy ions to induce nuclear reactions was reported as early as 1950. Since then it has been one of the most active areas of nuclear research. Intense beams of ions as heavy as uranium with energies high enough to overcome the Coulomb barriers of even the heaviest elements are available. The large variety of possible reactions gives rise to a multitude of products, which have been studied by many chemical and physical techniques. Chemical techniques have been of special value for the separation and unequivocal identification of low-yield species from the plethora of other nuclides present. Heavy-ion reactions have been essential for the production of the transmendelevium elements and a host of new isotopes. The systematics of compound nucleus reactions, transfer reactions and deeply inelastic reactions have been elucidated using chemical techniques. The variety of chemical procedures and techniques which have been developed for the study of heavy-ion reactions and their products has been examined. The determination of the chemical properties of the transmendelevium elements, which are very short-lived and can only be produced an ''atom at a time'' via heavy-ion reactions, is discussed. (author)

Abundances, Ionization States, Temperatures, and FIP in Solar Energetic Particles

Science.gov (United States)

Reames, Donald V.

2018-04-01

The relative abundances of chemical elements and isotopes have been our most effective tool in identifying and understanding the physical processes that control populations of energetic particles. The early surprise in solar energetic particles (SEPs) was 1000-fold enhancements in {}3He/{}4He from resonant wave-particle interactions in the small "impulsive" SEP events that emit electron beams that produce type III radio bursts. Further studies found enhancements in Fe/O, then extreme enhancements in element abundances that increase with mass-to-charge ratio A/Q, rising by a factor of 1000 from He to Au or Pb arising in magnetic reconnection regions on open field lines in solar jets. In contrast, in the largest SEP events, the "gradual" events, acceleration occurs at shock waves driven out from the Sun by fast, wide coronal mass ejections (CMEs). Averaging many events provides a measure of solar coronal abundances, but A/Q-dependent scattering during transport causes variations with time; thus if Fe scatters less than O, Fe/O is enhanced early and depleted later. To complicate matters, shock waves often reaccelerate impulsive suprathermal ions left over or trapped above active regions that have spawned many impulsive events. Direct measurements of ionization states Q show coronal temperatures of 1-2 MK for most gradual events, but impulsive events often show stripping by matter traversal after acceleration. Direct measurements of Q are difficult and often unavailable. Since both impulsive and gradual SEP events have abundance enhancements that vary as powers of A/Q, we can use abundances to deduce the probable Q-values and the source plasma temperatures during acceleration, ≈3 MK for impulsive SEPs. This new technique also allows multiple spacecraft to measure temperature variations across the face of a shock wave, measurements otherwise unavailable and provides a new understanding of abundance variations in the element He. Comparing coronal abundances from SEPs

Patterns and trends of macrobenthic abundance, biomass and production in the deep Arctic Ocean

Directory of Open Access Journals (Sweden)

Renate Degen

2015-08-01

Full Text Available Little is known about the distribution and dynamics of macrobenthic communities of the deep Arctic Ocean. The few previous studies report low standing stocks and confirm a gradient with declining biomass from the slopes down to the basins, as commonly reported for deep-sea benthos. In this study, we investigated regional differences of faunal abundance and biomass, and made for the first time ever estimates of deep Arctic community production by using a multi-parameter artificial neural network model. The underlying data set combines data from recent field studies with published and unpublished data from the past 20 years, to analyse the influence of water depth, geographical latitude and sea-ice concentration on Arctic benthic communities. We were able to confirm the previously described negative relationship of macrofauna standing stock with water depth in the Arctic deep sea, while also detecting substantial regional differences. Furthermore, abundance, biomass and production decreased significantly with increasing sea-ice extent (towards higher latitudes down to values <200 ind m−2, <65 mg C m−2 and <73 mg C m−2 y−1, respectively. In contrast, stations under the seasonal ice zone regime showed much higher standing stock and production (up to 2500 mg C m−2 y−1, even at depths down to 3700 m. We conclude that particle flux is the key factor structuring benthic communities in the deep Arctic Ocean as it explains both the low values in the ice-covered Arctic basins and the higher values in the seasonal ice zone.

Capture from pair production as a beam loss mechanism for heavy ions at RHIC

International Nuclear Information System (INIS)

Feinberg, B.; Belkacem, A.; Claytor, N.; Dinneen, T.; Gould, H.

1997-05-01

Electron capture from electron-positron pair production is predicted to be a major source of beam loss for the heaviest ions at RHIC. Achieving the highest luminosity thus requires an understanding of the capture process. The authors report measurements of this process at Brookhaven National Laboratory's AGS using 10.8 GeV/nucleon Au 79+ projectiles on Au targets. Capture from pair production is a process in which the very high electromagnetic field involved in the collision of two relativistic heavy ions results in the production of an electron-positron pair with the capture of the electron by one of the ions. There are many theoretical papers published on capture from pair production with discrepancies between predicted cross sections. The experimental results are compared to theory and to previous experiments at 1 GeV/nucleon. The implications of extrapolations to RHIC energies are presented

Halogeno-substituted 2-aminobenzoic acid derivatives for negative ion fragmentation studies of N-linked carbohydrates.

Science.gov (United States)

Harvey, David J

2005-01-01

Negative ion electrospray mass spectra of high-mannose N-linked glycans derivatised with 2-aminobenzoic acids and ionised from solutions containing ammonium hydroxide gave prominent [M-H](-) ions accompanied by weaker [M-2H](2-) ions. Fragmentation of both types of ions gave prominent singly charged glycosidic cleavage ions containing the derivatised reducing terminus and ions from the non-reducing terminus that appeared to be products of cross-ring cleavages. Differentiation of these two groups of ions was conveniently achieved in a single spectrum by use of chloro- or bromo-substituted benzoic acids in order to label ions containing the derivative with an atom with a distinctive isotope pattern. Fragmentation of the doubly charged ions gave more abundant fragments, both singly and doubly charged, than did fragmentation of the singly charged ions, but information of chain branching was masked by the appearance of prominent ions produced by internal cleavages. Copyright (c) 2005 John Wiley & Sons, Ltd.

A Review on ϕ Meson Production in Heavy-Ion Collision

Directory of Open Access Journals (Sweden)

Md. Nasim

2015-01-01

Full Text Available The main aim of the relativistic heavy-ion experiment is to create extremely hot and dense matter and study the QCD phase structure. With this motivation, experimental program started in the early 1990s at the Brookhaven Alternating Gradient Synchrotron (AGS and the CERN Super Proton Synchrotron (SPS followed by Relativistic Heavy Ion Collider (RHIC at Brookhaven and recently at Large Hadron Collider (LHC at CERN. These experiments allowed us to study the QCD matter from center-of-mass energies (sNN 4.75 GeV to 2.76 TeV. The ϕ meson, due to its unique properties, is considered as a good probe to study the QCD matter created in relativistic collisions. In this paper we present a review on the measurements of ϕ meson production in heavy-ion experiments. Mainly, we discuss the energy dependence of ϕ meson invariant yield and the production mechanism, strangeness enhancement, parton energy loss, and partonic collectivity in nucleus-nucleus collisions. Effect of later stage hadronic rescattering on elliptic flow (v2 of proton is also discussed relative to corresponding effect on ϕ meson v2.

Striped bass ichthyoplankton abundance, mortality, and production estimation for the Potomac River population

International Nuclear Information System (INIS)

Polgar, T.T.

1977-01-01

Methods are developed for estimating, from field survey data, the mortality rate and production for each successive ichthyoplanktonic stage. The abundance estimators used in the computation of these quantities are also derived. An age-dependent, ichthyoplankton population model is developed assuming either a uniform age distribution or an exponential age distribution within each stage. Striped bass egg and larval data from a 1974 ichthyoplankton survey in the Potomac River are used in model computations. The various model estimates are evaluated qualitatively, and the usefulness and limitations of the models are discussed

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

International Nuclear Information System (INIS)

Shirkov, G.D.

1996-01-01

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

An ICR study of ion-molecule reactions of PH(n)+ ions. [of importance to interstellar chemistry, using ion cyclotron resonance techniques

Science.gov (United States)

Thorne, L. R.; Anicich, V. G.; Huntress, W. T.

1983-01-01

The reactions of PH(n)+ ions (n = 0-3) were examined with a number of neutrals using ion-cyclotron-resonance techniques. The reactions examined have significance for the distribution of phosphorus in interstellar molecules. The results indicate that interstellar molecules containing the P-O bond are likely to be more abundant than those containing the P-H bond.

Ion cyclotron and spin-flip emissions from fusion products in tokamaks

International Nuclear Information System (INIS)

Arunasalam, V.; Greene, G.J.; Young, K.M.

1993-02-01

Power emission by fusion products of tokamak plasmas in their ion cyclotron range of frequencies (ICRF) and at their spin-flip resonance frequency is calculated for some specific model fusion product velocity-space distribution functions. The background plasma of say deuterium (D) is assumed to be in equilibrium with a Maxwellian distribution both for the electrons and ions. The fusion product velocity distributions analyzed here are: (1) A monoenergetic velocity space ring distribution. (2) A monoenergetic velocity space spherical shell distribution. (3) An anisotropic Maxwellian distribution with T perpendicular ≠ T parallel and with appreciable drift velocity along the confining magnetic field. Single ''dressed'' test particle spontaneous emission calculations are presented first and the radiation temperature for ion cyclotron emission (ICE) is analyzed both for black-body emission and nonequilibrium conditions. Thresholds for instability and overstability conditions are then examined and quasilinear and nonlinear theories of the electromagnetic ion cyclotron modes are discussed. Distinctions between ''kinetic or causal instabilities'' and ''hydrodynamic instabilities'' are drawn and some numerical estimates are presented for typical tokamak parameters. Semiquantitative remarks are offered on wave accessibility, mode conversion, and parametric decay instabilities as possible for spatially localized ICE. Calculations are carried out both for k parallel = 0 for k parallel ≠ 0. The effects of the temperature anisotropy and large drift velocities in the parallel direction are also examined. Finally, proton spin-flip resonance emission and absorption calculations are also presented both for thermal equilibrium conditions and for an ''inverted'' population of states

Ion cyclotron and spin-flip emissions from fusion products in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Arunasalam, V.; Greene, G.J.; Young, K.M.

1993-02-01

Power emission by fusion products of tokamak plasmas in their ion cyclotron range of frequencies (ICRF) and at their spin-flip resonance frequency is calculated for some specific model fusion product velocity-space distribution functions. The background plasma of say deuterium (D) is assumed to be in equilibrium with a Maxwellian distribution both for the electrons and ions. The fusion product velocity distributions analyzed here are: (1) A monoenergetic velocity space ring distribution. (2) A monoenergetic velocity space spherical shell distribution. (3) An anisotropic Maxwellian distribution with T [perpendicular] [ne] T[parallel]and with appreciable drift velocity along the confining magnetic field. Single dressed'' test particle spontaneous emission calculations are presented first and the radiation temperature for ion cyclotron emission (ICE) is analyzed both for black-body emission and nonequilibrium conditions. Thresholds for instability and overstability conditions are then examined and quasilinear and nonlinear theories of the electromagnetic ion cyclotron modes are discussed. Distinctions between kinetic or causal instabilities'' and hydrodynamic instabilities'' are drawn and some numerical estimates are presented for typical tokamak parameters. Semiquantitative remarks are offered on wave accessibility, mode conversion, and parametric decay instabilities as possible for spatially localized ICE. Calculations are carried out both for k[parallel] = 0 for k[parallel] [ne] 0. The effects of the temperature anisotropy and large drift velocities in the parallel direction are also examined. Finally, proton spin-flip resonance emission and absorption calculations are also presented both for thermal equilibrium conditions and for an inverted'' population of states.

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

Detection of fission products in carbon dioxide by instantaneous ion collection

International Nuclear Information System (INIS)

Le Meur, R.; Lorin, A.

1968-01-01

This report describes a fission product detector with instantaneous electric collection, capable of analyzing carbon dioxide up to a pressure of 60 bars and at a temperature of 200 C. In contrast to delayed collection detectors, this apparatus makes it possible to collect rubidium and cesium ions as soon as they are formed; this avoids losses due to recombination. The detector has been tested with a fission product source made up of a uranium oxide sample subjected to a neutron flux. The activity of the ions collected as a function of an electric field has been measured for different parameters: pressure, temperature, CO 2 gas flow rate, and the volume of the ion-formation chamber. The sensitivity of this apparatus is compared to that of other fission product detectors. For a low volume-flow rate, e.g. 100 cm 3 sec -1 , its sensitivity for krypton 88 is better than that of a delayed collection detector. An apparatus of this type could be used as a can rupture detector on a reactor with a large number of channels, with a low gas sampling rate per channel. The equipment will be included in the can rupture detector installations in the Fessenheim reactor. (authors) [fr

Defect production and annihilation in metals through electronic excitation by energetic heavy ion bombardment

Energy Technology Data Exchange (ETDEWEB)

Iwase, Akihiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

Defect production, radiation annealing and defect recovery are studied in Ni and Cu irradiated with low-energy ({approx}1-MeV) and high-energy ({approx}100-MeV) ions. Irradiation of Ni with {approx}100-MeV ions causes an anomalous reduction, or even a complete disappearance of the stage-I recovery. This result shows that the energy transferred from excited electrons to lattice atoms through the electron-lattice interaction contributes to the annihilation of the stage-I interstitials. This effect is also observed in Ni as a large radiation annealing during 100-MeV heavy ion irradiation. On the other hand, in Cu thin foils, we find the defect production process strongly associated with electron excitation, where the defect production cross section is nearly proportional to S{sub e}{sup 2}. (author)

Alkyne End Group Production in Polymeric Materials Induced by Swift Heavy Ion Irradiations

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Swift heavy ions in matter lose energy mainly through electronic processes.Since the energy deposition is centered in a very small region with a very high energy density,new effects such as production of alkyne end group can be induced.In this work,PET,PS,PC and PI films are irradiated with Ar,Kr,Xe and U ions and the relationship of the alkyne end group production with electronic energy loss is studied by Fourier transformed infrared infrared(FTLR)spectra measurements.

Defect production in natural diamond irradiated with high energy Ni ions

International Nuclear Information System (INIS)

Varichenko, V.S.; Martinovich, V.A.; Penina, N.M.; Zajtsev, A.M.; Stel'makh, V.F.; Didyk, A.Yu.; Fahrner, W.R.

1995-01-01

Defect production in diamond irradiated by 335 MeV Ni ions within a dose range of 5 · 10 12 - 5 · 10 14 cm -2 has been studied by electron paramagnetic resonance (EPR) method. The irradiation leads to the appearance in diamond lattice of quasi-one-dimensional track like structures with non tetrahedral atomic configurations. Possible mechanism of microwave conductivity in the modified structures is discussed. Peculiarities of depth distribution profile of concentration of paramagnetic centres in modified structures are explained by track channeling and by stopped ions because of their elastic collisions with lattice atoms during ion stopping. (author). 24 refs., 4 figs., 1 tab

Recoil ion spectroscopy with heavy ions

International Nuclear Information System (INIS)

Beyer, H.F.; Mann, R.

1984-01-01

This chapter examines the production of very high charge state ions in single ion-atom collisions. Topics considered include some aspects of highly ionized atoms, experimental approaches, the production of highly charged target ions (monoatomic targets, recoil energy distribution, molecular fragmentation, outer-shell rearrangement, lifetime measurements, a comparison of projectile-, target-, and plasma-ion stripping), and secondary collision experiments (selective electron capture, potential applications). The heavy-ion beams for the described experiments were provided by accelerators such as tandem Van de Graaff facility and the UNILAC

Simulated production rates of exotic nuclei from the ion guide for neutron-induced fission at IGISOL

Energy Technology Data Exchange (ETDEWEB)

Jansson, Kaj; Al-Adili, Ali; Nilsson, Nicklas; Norlin, Martin; Solders, Andreas [Uppsala University, Department of Physics and Astronomy, Uppsala (Sweden)

2017-12-15

An investigation of the stopping efficiency of fission products, in the new ion guide designed for ion production through neutron-induced fission at IGISOL in Jyvaeskylae, Finland, has been conducted. Our simulations take into account the new neutron converter, enabling measurements of neutron-induced fission yields, and thereby provide estimates of the obtained yields as a function of primary proton beam current. Different geometries, targets, and pressures, as well as models for the effective charge of the stopped ions were tested, and optimisations to the setup for higher yields are suggested. The predicted number of ions stopped in the gas lets us estimate the survival probability of the ions reaching the downstream measurements stations. (orig.)

Deuteron and anti-deuteron production in CERN experiment NA44

International Nuclear Information System (INIS)

Simon-Gillo, J.

1995-01-01

The abundances of light nuclei probe the later stages of the evolution of a system formed in a relativistic heavy-ion collision. After the system has cooled and expanded, nucleons in close proximity and moving with small relative momenta coalesce to form nuclei. Light nuclei production enables the study of several topics, including the mechanism of composite particle production, freeze-out temperature, size of the interaction region, and entropy of the system. NA44 is the only relativistic heavy-ion experiment to have both deuteron and anti-deuteron results in both pA and AA collisions and the first CERN experiment to study the physics topics addressed by d and bar d production

Recent experiments towards production and diagnostics of nitrogen ion beam for medium-mass ion beam ICF

Energy Technology Data Exchange (ETDEWEB)

Kasuya, K [Tokyo Inst. of Tech., Yokohama (Japan). Dept. of Energy Sciences; Yasuike, K; Miyamoto, S [Osaka Univ. (Japan). Inst. of Laser Engineering; and others

1997-12-31

Three research teams are collaborating in the title topics. The first group presented proposals and preliminary results on (1) re-operation of cryogenic diode for nitrogen beam, (2) laser plasma production to supply ion source, (3) application of CCD camera element to advanced particle detector, (4) application of cryogenic technique to advanced material production method, and (5) reform of UV laser for future diode cleaning or plasma production. The joint 2nd and 3rd groups present (6) most recent results of time- and space-dependent particle beam diagnostics by an advanced arrayed pin-hole camera. (orig.). 5 figs., 6 refs.

A Model for Negative Ion Chemistry in Titan’s Ionosphere

Science.gov (United States)

Mukundan, Vrinda; Bhardwaj, Anil

2018-04-01

We developed a one-dimensional photochemical model for the dayside ionosphere of Titan for calculating the density profiles of negative ions under steady-state photochemical equilibrium condition. We concentrated on the T40 flyby of the Cassini orbiter and used the in situ measurements from instruments on board Cassini as input to the model. Using the latest available reaction rate coefficients and dissociative electron attachment cross sections, the densities of 10 anions are calculated. Our study shows CN‑ as the dominant anion, followed by C3N‑, which agrees with the results of previous calculations. We suggest that H‑ could be an important anion in Titan’s ionosphere and is the second most abundant anion at altitudes greater than 1200 km. The main production channel of the major ion CN‑ is the reaction of H‑ with HCN. The H‑ also play a major role in the production of anions C2H‑, C6H‑, and OH‑. We present a comparison of the calculated ion density profiles with the relative density profiles derived using recently reported Cassini CAPS/ELS observations.

Visible-light activate Ag/WO3 films based on wood with enhanced negative oxygen ions production properties

Science.gov (United States)

Gao, Likun; Gan, Wentao; Cao, Guoliang; Zhan, Xianxu; Qiang, Tiangang; Li, Jian

2017-12-01

The Ag/WO3-wood was fabricated through a hydrothermal method and a silver mirror reaction. The system of visible-light activate Ag/WO3-wood was used to produce negative oxygen ions, and the effect of Ag nanoparticles on negative oxygen ions production was investigated. From the results of negative oxygen ions production tests, it can be observed that the sample doped with Ag nanoparticles, the concentration of negative oxygen ions is up to 1660 ions/cm3 after 60 min visible light irradiation. Moreover, for the Ag/WO3-wood, even after 60 min without irradiation, the concentration of negative oxygen ions could keep more than 1000 ions/cm3, which is up to the standard of the fresh air. Moreover, due to the porous structure of wood, the wood acted as substrate could promote the nucleation of nanoparticles, prevent the agglomeration of the particles, and thus lead the improvement of photocatalytic properties. And such wood-based functional materials with the property of negative oxygen ions production could be one of the most promising materials in the application of indoor decoration materials, which would meet people's pursuit of healthy, environment-friendly life.

Universal behavior of charged particle production in heavy ion collisions

Science.gov (United States)

Phobos Collaboration; Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

2003-03-01

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

Light ion production for a future radiobiological facility at CERN: preliminary studies.

Science.gov (United States)

Stafford-Haworth, Joshua; Bellodi, Giulia; Küchler, Detlef; Lombardi, Alessandra; Röhrich, Jörg; Scrivens, Richard

2014-02-01

Recent medical applications of ions such as carbon and helium have proved extremely effective for the treatment of human patients. However, before now a comprehensive study of the effects of different light ions on organic targets has not been completed. There is a strong desire for a dedicated facility which can produce ions in the range of protons to neon in order to perform this study. This paper will present the proposal and preliminary investigations into the production of light ions, and the development of a radiobiological research facility at CERN. The aims of this project will be presented along with the modifications required to the existing linear accelerator (Linac3), and the foreseen facility, including the requirements for an ion source in terms of some of the specification parameters and the flexibility of operation for different ion types. Preliminary results from beam transport simulations will be presented, in addition to some planned tests required to produce some of the required light ions (lithium, boron) to be conducted in collaboration with the Helmholtz-Zentrum für Materialien und Energie, Berlin.

Hydrolysis of VX on concrete: rate of degradation by direct surface interrogation using an ion trap secondary ion mass spectrometer.

Science.gov (United States)

Groenewold, Gary S; Williams, John M; Appelhans, Anthony D; Gresham, Garold L; Olson, John E; Jeffery, Mark T; Rowland, Brad

2002-11-15

The nerve agent VX (O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate) is lethal at very low levels of exposure, which can occur by dermal contact with contaminated surfaces. Hence, behavior of VX in contact with common urban or industrial surfaces is a subject of acute interest. In the present study, VX was found to undergo complete degradation when in contact with concrete surfaces. The degradation was directly interrogated at submonolayer concentrations by periodically performing secondary ion mass spectrometry (SIMS) analyses after exposure of the concrete to VX. The abundance of the [VX + H]+ ion in the SIMS spectra was observed to decrease in an exponential fashion, consistent with first-order or pseudo-first-order behavior. This phenomenon enabled the rate constant to be determined at 0.005 min(-1) at 25 degrees C, which corresponds to a half-life of about 3 h on the concrete surface. The decrease in [VX + H]+ was accompanied by an increase in the abundance of the principal degradation product diisopropylaminoethanethiol (DESH), which arises by cleavage of the P-S bond. Degradation to form DESH is accompanied by the formation of ethyl methylphosphonic acid, which is observable only in the negative ion spectrum. A second degradation product was also implicated, which corresponded to a diisopropylvinylamine isomer (perhaps N,N-diisopropyl aziridinium) that arose via cleavage of the S-C bond. No evidence was observed for the formation of the toxic S-2-diisopropylaminoethyl methylphosphonothioic acid. The degradation rate constants were measured at four different temperatures (24-50 degrees C), which resulted in a linear Arrhenius relationship and an activation energy of 52 kJ mol(-1). This value agrees with previous values observed for VX hydrolysis in alkaline solutions, which suggests that the degradation of submonolayer VX is dominated by alkaline hydrolysis within the adventitious water film on the concrete surface.

Particle-production mechanism in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Bush, B.W.; Nix, J.R.

1994-01-01

We discuss the production of particles in relativistic heavy-ion collisions through the mechanism of massive bremsstrahlung, in which massive mesons are emitted during rapid nucleon acceleration. This mechanism is described within the framework of classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach to relativistic heavy-ion collisions that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomena, interactions among all nucleons, and particle production. Inclusion of the finite nucleon size cures the difficulties with preacceleration and runaway solutions that have plagued the classical theory of self-interacting point particles. For the soft reactions that dominate nucleon-nucleon collisions, a significant fraction of the incident center-of-mass energy is radiated through massive bremsstrahlung. In the present version of the theory, this radiated energy is in the form of neutral scalar (σ) and neutral vector (ω) mesons, which subsequently decay primarily into pions with some photons also. Additional meson fields that are known to be important from nucleon-nucleon scattering experiments should be incorporated in the future, in which case the radiated energy would also contain isovector pseudoscalar (π + , π - , π 0 ), isovector scalar (δ + , δ - , δ 0 ), isovector vector (ρ + , ρ - , ρ 0 ), and neutral pseudoscalar (η) mesons

Recent progress in nonperturbative electromagnetic lepton-pair production with capture in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Wells, J.C.; Oberacker, V.E.; Umar, A.S.

1993-01-01

The prospect of new colliding-beam accelerators capable of producing collisions of highly stripped high-Z ions, at fixed-target energies per nucleon up to 20 TeV or more, has motivated much interest in lepton-pair production from the QED vacuum. The time-dependent and essentially classical electromagnetic fields involved in such collisions contain larger Fourier components which give rise to sizable lepton-pair production in addition to many other exotic particles. The process of electron-positron production with electron capture is a principal beam-loss mechanism for highly charged ions in a storage ring. In this process, the electron is created in a bound state of one of the participant heavy ions (most likely the 1s state), thus changing the ion's charge state and causing it to be deflected out of the beam. There is a long and sometimes controversial history concerning the use of perturbative methods in studying electromagnetic lepton-pair production; however, reliable perturbative calculations have been used as input into design models for the Relativistic Heavy-Ion Collider (RHIC). Applying perturbation theory to these processes at high energies and small impact parameters results in probabilities which violate unitarity, and cross sections which violate the Froissart bound. This evidence, along with the initial nonperturbative studies, suggests that higher-order QED effects will be important for extreme relativistic collisions. Clearly, large nonperturbative effects in electron-pair production with capture would have important implications for RHIC. In this paper, the authors briefly discuss recent progress in nonperturbative studies of the capture problem. In Section 2, they state the Dirac equation for a lepton in the time-dependent external field of a heavy ion which must be solved to compute lepton-capture probabilities. Section 4 surveys results from recent applications of coupled-channel and lattice techniques to the lepton-capture problem

Enhanced production of L-sorbose from D-sorbitol by improving the mRNA abundance of sorbitol dehydrogenase in Gluconobacter oxydans WSH-003.

Science.gov (United States)

Xu, Sha; Wang, Xiaobei; Du, Guocheng; Zhou, Jingwen; Chen, Jian

2014-10-18

Production of L-sorbose from D-sorbitol by Gluconobacter oxydans is the first step to produce L-ascorbic acid on industrial scale. The sldhAB gene, which encodes the sorbitol dehydrogenase (SLDH), was overexpressed in an industrial strain G. oxydans WSH-003 with a strong promoter, P tufB . To enhance the mRNA abundance, a series of artificial poly(A/T) tails were added to the 3'-terminal of sldhAB gene. Besides, their role in sldhAB overexpression and their subsequent effects on L-sorbose production were investigated. The mRNA abundance of the sldhAB gene could be enhanced in G. oxydans by suitable poly(A/T) tails. By self-overexpressing the sldhAB gene in G. oxydans WSH-003 with an optimal poly(A/T) tail under the constitutive promoter P tufB , the titer and the productivity of L-sorbose were enhanced by 36.3% and 25.0%, respectively, in a 1-L fermenter. Immobilization of G. oxydans-sldhAB6 cells further improved the L-sorbose titer by 33.7% after 20 days of semi-continuous fed-batch fermentation. The artificial poly(A/T) tails could significantly enhance the mRNA abundance of the sldhAB. Immobilized G. oxydans-sldhAB6 cells could further enlarge the positive effect caused by enhanced mRNA abundance of the sldhAB.

Heavy ion irradiation of astrophysical ice analogs

International Nuclear Information System (INIS)

Duarte, Eduardo Seperuelo; Domaracka, Alicja; Boduch, Philippe; Rothard, Hermann; Balanzat, Emmanuel; Dartois, Emmanuel; Pilling, Sergio; Farenzena, Lucio; Frota da Silveira, Enio

2009-01-01

Icy grain mantles consist of small molecules containing hydrogen, carbon, oxygen and nitrogen atoms (e.g. H 2 O, GO, CO 2 , NH 3 ). Such ices, present in different astrophysical environments (giant planets satellites, comets, dense clouds, and protoplanetary disks), are subjected to irradiation of different energetic particles: UV radiation, ion bombardment (solar and stellar wind as well as galactic cosmic rays), and secondary electrons due to cosmic ray ionization of H 2 . The interaction of these particles with astrophysical ice analogs has been the object of research over the last decades. However, there is a lack of information on the effects induced by the heavy ion component of cosmic rays in the electronic energy loss regime. The aim of the present work is to simulate of the astrophysical environment where ice mantles are exposed to the heavy ion cosmic ray irradiation. Sample ice films at 13 K were irradiated by nickel ions with energies in the 1-10 MeV/u range and analyzed by means of FTIR spectrometry. Nickel ions were used because their energy deposition is similar to that deposited by iron ions, which are particularly abundant cosmic rays amongst the heaviest ones. In this work the effects caused by nickel ions on condensed gases are studied (destruction and production of molecules as well as associated cross sections, sputtering yields) and compared with respective values for light ions and UV photons. (authors)

Measurement of quarkonia production in heavy-ion collisions with the ATLAS detector

CERN Document Server

Kremer, Jakub Andrzej; The ATLAS collaboration

2017-01-01

The suppression of heavy quarkonia states in heavy-ion collisions is a phenomenon understood as a consequence of QGP formation in the hot, dense system formed in nucleus-nucleus collisions at the LHC. In addition to hot matter effects in heavy-ion collisions, cold nuclear effects may also affect quarkonia production. Therefore, a full assessment requires detailed studies on the effects present in both A+A and $\\textit{p}$+A collisions. Based on $\\textit{p}$+Pb data collected in 2013 and $\\textit{pp}$ and Pb+Pb data collected in 2015 at the LHC, the ATLAS experiment has studied prompt and non-prompt $J/\\psi$ and $\\psi\\left(2\\mathrm{S}\\right)$ productions as well as $\\Upsilon\\left(n\\mathrm{S}\\right)$ production via the di-muon decay final states. The results of the various measurements are discussed.

Stellar Oxygen Abundances

Science.gov (United States)

King, Jeremy

1994-04-01

This dissertation addresses several issues concerning stellar oxygen abundances. The 7774 {\\AA} O I triplet equivalent widths of Abia & Rebolo [1989, AJ, 347, 186] for metal-poor dwarfs are found to be systematically too high. I also argue that current effective temperatures used in halo star abundance studies may be ~150 K too low. New color-Teff relations are derived for metal-poor stars. Using the revised Teff values and improved equivalent widths for the 7774A O I triplet, the mean [O/Fe] ratio for a handful of halo stars is found to be +0.52 with no dependence on Teff or [Fe/H]. Possible cosmological implications of the hotter Teff scale are discussed along with additional evidence supporting the need for a higher temperature scale for metal-poor stars. Our Teff scale leads to a Spite Li plateau value of N(Li)=2.28 +/- 0.09. A conservative minimal primordial value of N(Li)=2.35 is inferred. If errors in the observations and models are considered, consistency with standard models of Big Bang nucleosynthesis is still achieved with this larger Li abundance. The revised Teff scale raises the observed B/Be ratio of HD 140283 from 10 to 12, making its value more comfortably consistent with the production of the observed B and Be by ordinary spallation. Our Teff values are found to be in good agreement with values predicted from both the Victoria and Yale isochrone color-Teff relations. Thus, it appears likely that no changes in globular cluster ages would result. Next, we examine the location of the break in the [O/Fe] versus [Fe/H] plane in a quantitative fashion. Analysis of a relatively homogeneous data set does not favor any unique break point in the range -1.7 /= -3), in agreement with the new results for halo dwarfs. We find that the gap in the observed [O/H] distribution, noted by Wheeler et al. [1989, ARAA, 27, 279], persists despite the addition of more O data and may betray the occurrence of a hiatus in star formation between the end of halo formation and

Effects of habitat-forming species richness, evenness, identity, and abundance on benthic intertidal community establishment and productivity.

Directory of Open Access Journals (Sweden)

Julie Lemieux

Full Text Available In a context of reduced global biodiversity, the potential impacts from the loss of habitat-forming species (HFS on ecosystem structure and functioning must be established. These species are often the main community primary producers and have a major role in the establishment of organisms through facilitation processes. This study focuses on macroalgae and mussels as HFS within an intertidal zone along the St. Lawrence estuary (Quebec, Canada. Over a 16-week period, we manipulated the in situ diversity profile (richness, evenness, identity, and abundance of the dominant HFS (Fucus distichus edentatus, F. vesiculosus, and Mytilus spp. in order to define their role in both the establishment of associated species and community primary production. Contrary to expectation, no general change in HFS richness, evenness, abundance, or identity on associated species community establishment was observed. However, over the study period, the HFS diversity profile modified the structure within the trophic guilds, which may potentially affect further community functions. Also, our results showed that the low abundance of HFS had a negative impact on the primary productivity of the community. Our results suggest that HFS diversity profiles have a limited short-term role in our study habitat and may indicate that biological forcing in these intertidal communities is less important than environmental conditions. As such, there was an opportunistic establishment of species that ensured rapid colonization regardless of the absence, or the diversity profile, of facilitators such as HFS.

Actinide production in the reaction of heavy ions with curium-248

International Nuclear Information System (INIS)

Moody, K.J.

1983-07-01

Chemical experiments were performed to examine the usefulness of heavy ion transfer reactions in producing new, neutron-rich actinide nuclides. A general quasi-elastic to deep-inelastic mechanism is proposed, and the utility of this method as opposed to other methods (e.g. complete fusion) is discussed. The relative merits of various techniques of actinide target synthesis are discussed. A description is given of a target system designed to remove the large amounts of heat generated by the passage of a heavy ion beam through matter, thereby maximizing the beam intensity which can be safely used in an experiment. Also described is a general separation scheme for the actinide elements from protactinium (Z=91) to mendelevium (Z=101), and fast specific procedures for plutonium, americium and berkelium. The cross sections for the production of several nuclides from the bombardment of 248 Cm with 18 O, 86 Kr and 136 Xe projectiles at several energies near and below the Coulomb barrier were determined. The results are compared with yields from 48 Ca and 238 U bombardments of 248 Cm. Simple extrapolation of the product yields into unknown regions of charge and mass indicates that the use of heavy ion transfer reactions to produce new, neutron-rich above-target species is limited. The substantial production of neutron-rich below-target species, however, indicates that with very heavy ions like 136 Xe and 238 U the new species 248 Am, 249 Am and 247 Pu should be produced with large cross sections from a 248 Cm target. A preliminary, unsuccessful attempt to isolate 247 Pu is outlined. The failure is probably due to the half life of the decay, which is calculated to be less than 3 minutes. The absolute gamma ray intensities from 251 Bk decay, necessary for calculating the 251 Bk cross section, are also determined

Ion-molecule reactions in alkynes

International Nuclear Information System (INIS)

Lifshitz, C.; Weiss, M.

1980-01-01

Fragment ions from 1,5-hexadiyne are trapped in an electron space charge and allowed to react with the neutral 1,5-hexadiyne present. The reactivities are similar to those of ions of the same elementary formulae in the benzene system. Secondary ions of major abundance observed are, in decreasing order of importance: C 10 H + 8 , C 9 H + 7 , C 12 H + 8 , C 12 H + 9 and C 7 H + 7 . In contrast to the benzene system, the ion C 12 H + 11 is of minor importance. (orig.)

Effect of the gas mixing technique on the production efficiency of ion beams extracted from an electron cyclotron resonance ion source

International Nuclear Information System (INIS)

Tarvainen, O.; Suominen, P.; Koivisto, H.

2004-01-01

In this work the effect of gas mixing on the production efficiency of ion beams extracted from an ECR ion source has been studied with the JYFL 6.4 GHz electron cyclotron resonance ion source (ECRIS). It was found that the gas mixing affects strongly the confinement of ions in the plasma of the ECRIS. The information obtained can be used to minimize the consumption of expensive materials or isotopes and to reduce contamination of the plasma chamber. It was observed that the carbon contamination, which is built up when the MIVOC method is used could be decreased with the aid of the gas mixing technique. The best mixing gas for this purpose was found to be oxygen

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

Experimental particle formation rates spanning tropospheric sulfuric acid and ammonia abundances, ion production rates, and temperatures

CERN Document Server

Kürten, Andreas; Almeida, Joao; Kupiainen-Määttä, Oona; Dunne, Eimear M.; Duplissy, Jonathan; Williamson, Christina; Barmet, Peter; Breitenlechner, Martin; Dommen, Josef; Donahue, Neil M.; Flagan, Richard C.; Franchin, Alessandro; Gordon, Hamish; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Ickes, Luisa; Jokinen, Tuija; Kangasluoma, Juha; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Onnela, Antti; Ortega, Ismael K.; Petäjä, Tuukka; Praplan, Arnaud P.; Riccobono, Francesco; Rissanen, Matti P.; Rondo, Linda; Schnitzhofer, Ralf; Schobesberger, Siegfried; Smith, James N.; Steiner, Gerhard; Stozhkov, Yuri; Tomé, António; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Wagner, Paul E.; Wimmer, Daniela; Ye, Penglin; Baltensperger, Urs; Carslaw, Ken; Kulmala, Markku; Curtius, Joachim

2016-01-01

Binary nucleation of sulfuric acid and water as well as ternary nucleation involving ammonia arethought to be the dominant processes responsible for new particle formation (NPF) in the cold temperaturesof the middle and upper troposphere. Ions are also thought to be important for particle nucleation inthese regions. However, global models presently lack experimentally measured NPF rates under controlledlaboratory conditions and so at present must rely on theoretical or empirical parameterizations. Here withdata obtained in the European Organization for Nuclear Research CLOUD (Cosmics Leaving OUtdoor Droplets)chamber, we present the first experimental survey of NPF rates spanning free tropospheric conditions. Theconditions during nucleation cover a temperature range from 208 to 298 K, sulfuric acid concentrationsbet ween 5 × 105and 1 × 109cm3, and ammonia mixing ratios from zero added ammonia, i.e., nominally purebinary, to a maximum of ~1400 parts per trillion by volume (pptv). We performed nucleation s...

Construction of Rb charge exchange cell and characteristic experiment for He- ion production

International Nuclear Information System (INIS)

Lee, Hee Seock; Bak, Jun Gyo; Bak, Hae Ill

1991-01-01

The Rb charge exchange cell is constructed as the He - ion source of the SNU 1.5-MV Tandem Van de Graaff accelerator. the characteristic experiments is carried out in order to determine the optimum operational conditions of the cell. The He + ion beam with the energy of 1 - 10 keV, extracted from the duoplasmatron ion source, is passed through the Rb vapor to become He - ions by the two step charge exchange reaction, i.e., He + + Rb → He o* + Rb + and He o* + Rb → He - + Rb + . From the experimental results, it is found that the maximum fractional yield of He - ions is produced at He + /ion energy of 7 keV. The optimum temperatures of the oven and the canal are determined to be 370 deg C and 95 deg C respectively. Under the optimum operational condition the maximum fractional yield of He - ions is 2.42 ± 0.02 5. This charge exchange cell is proved to be an effective system for the production of He - ions. (Author)

Antiproton production in heavy-ion collisions at energies below the threshold

International Nuclear Information System (INIS)

Schroeter, A.

1993-08-01

In the framework of this thesis the antiproton production in heavy ion collisions at projectile energies far below the threshold for anti p production in nucleon-nucleon collisions (5.63 GeV/u) was studied. A suited detection apparature was developed and constructed at the fragment separator-magnet spectrometer at the Society for Heavy Ion Research (GSI). For the identification of the antiprotons the momentum of the particles emitted in beam direction was measured and their velocity multiple-redundantly determined by means of time-of-flight measurements and threshold Cherenkov detectors. By this way the antiprotons could be in spite of low anti p production cross sections and high production rates for lighter particles (R anti p: R K - -:R π - -∼1:5*10 3 :10 7 ) background-freely determined. By this experiment for Ne+NaF, Cu, Sn, and Bi as well ass Ni+Ni collisions at incident energies between 1.6 GeV/u and 2.0 GeV/u production cross sections for antiprotons in the momentum range between 1.0 GeV/c and 2.2 GeV/c and for kaons and pions between 0.5 GeV/c and 2.8 GeV/c were measured, in order to study the influence of collisional-system size, incident energy, and secondary-particle momentum on the production probabilities and to contribute in comparison with the prognoses of theoretical models to the explanation of the particle production mechanisms. (HSI)

Nuclear abundances and evolution of the interstellar medium

International Nuclear Information System (INIS)

Wannier, P.G.

1980-01-01

Observations of molecular and elemental abundances in the interstellar medium (ISM) are reviewed, with special attention given to isotope ratios. The derivation of molecular isotope abundances for the ISM is discussed, along with H and C fractionation. Millimeter- and centimeter-wave spectra of giant clouds are examined with respect to isotope abundances of C, O, N, Si, S, and D. Evidence for the current enrichment of the ISM by mass loss from evolved stars is considered, together with chemical abundance gradients in H II regions and planetary nebulae. Cosmic-ray observations pertaining to abundances in the ISM are summarized, with emphasis on available results for Ne, Mg, Si, Fe, and Ni. The observations reviewed are shown to support arguments in favor of: (1) the cosmological production of D and He-3 (2) the production of the CNO elements by hydrostatic hydrogen burning (3) the nucleosynthesis of Ne, Mg, Si, S, Fe, and Ni as a result of He burning (4) solar abundances of interstellar S, Fe, and Ni and (5) a direct association between observed inhomogeneities in the ISM and mass loss from evolved stellar objects

Structure and further fragmentation of significant [a3 + Na - H]+ ions from sodium-cationized peptides.

Science.gov (United States)

Wang, Huixin; Wang, Bing; Wei, Zhonglin; Zhang, Hao; Guo, Xinhua

2015-01-01

A good understanding of gas-phase fragmentation chemistry of peptides is important for accurate protein identification. Additional product ions obtained by sodiated peptides can provide useful sequence information supplementary to protonated peptides and improve protein identification. In this work, we first demonstrate that the sodiated a3 ions are abundant in the tandem mass spectra of sodium-cationized peptides although observations of a3 ions have rarely been reported in protonated peptides. Quantum chemical calculations combined with tandem mass spectrometry are used to investigate this phenomenon by using a model tetrapeptide GGAG. Our results reveal that the most stable [a3 + Na - H](+) ion is present as a bidentate linear structure in which the sodium cation coordinates to the two backbone carbonyl oxygen atoms. Due to structural inflexibility, further fragmentation of the [a3 + Na - H](+) ion needs to overcome several relatively high energetic barriers to form [b2 + Na - H](+) ion with a diketopiperazine structure. As a result, low abundance of [b2 + Na - H](+) ion is detected at relatively high collision energy. In addition, our computational data also indicate that the common oxazolone pathway to generate [b2 + Na - H](+) from the [a3 + Na - H](+) ion is unlikely. The present work provides a mechanistic insight into how a sodium ion affects the fragmentation behaviors of peptides. Copyright © 2015 John Wiley & Sons, Ltd.

Quarkonium production in heavy-ion collisions

International Nuclear Information System (INIS)

Arnaldi, R.

2014-01-01

The production of quarkonium states (cc-bar or bb-bar bound states) plays a crucial role among the probes to investigate the formation of the plasma of quarks and gluons (QGP) in heavy-ion collisions. A review of the charmonium and bottomonium production, mainly focussing on the latest results from the LHC experiments, is presented. The comparison of several quarkonium states and the different but complementary, kinematic regions now accessible by the LHC experiments, allows us to get further insight on how the hot created medium is affecting the various resonances. Results have shown that, at LHC energies, there are 2 competing processes, the suppression in the deconfined medium and the (re)combination of q and q-bar states, which have a different role depending on the quarkonium states and on the kinematic region under study. At the same time, other probes, as higher excited states (Ψ(2S), Υ(3S)...), or observables as the J/Ψ flow, are still affected by the lack of statistics which prevents us from drawing firm conclusions on their behaviour

Relativistic ion collisions as the source of hypernuclei

Energy Technology Data Exchange (ETDEWEB)

Botvina, A.S. [J.W. Goethe University, Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Russian Academy of Sciences, Institute for Nuclear Research, Moscow (Russian Federation); Bleicher, M.; Steinheimer, J. [J.W. Goethe University, Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Pochodzalla, J. [J. Gutenberg-Universitaet, Helmholtz-Institut Mainz, Mainz (Germany); J. Gutenberg-Universitaet Mainz, Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany)

2016-08-15

We shortly review the theory of hypernuclei production in relativistic ion collisions, that is adequate to future experiments at BM rate at N, NICA, and FAIR. Within a hybrid approach we use transport, coalescence and statistical models to describe the whole process. We demonstrate that the origin of hypernuclei can be explained by typical baryon interactions, that is similar to the production of conventional nuclei. In particular, heavy hypernuclei are coming mostly from projectile and target residues, whereas light hypernuclei can be produced at all rapidities. The yields of hypernuclei increase considerably above the energy threshold for Λ hyperon production, and there is a tendency to saturation of yields of hypernuclei with increasing the beam energy up to few TeV. There are unique opportunities in relativistic ion collisions which are difficult to realize in traditional hypernuclear experiments: The produced hypernuclei have a broad distribution in masses and isospin. They can even reach beyond the neutron and proton drip-lines and that opens a chance to investigate properties of exotic hypernuclei. One finds also the abundant production of multi-strange nuclei, of bound and unbound hypernuclear states with new decay modes. In addition, we can directly get an information on the hypermatter both at high and low temperatures. (orig.)

Coupled channel calculations for electron-positron pair production in collisions of heavy ions

CERN Document Server

Gail, M; Scheid, W

2003-01-01

Coupled channel calculations are performed for electron-positron pair production in relativistic collisions of heavy ions. For this purpose the wavefunction is expanded into different types of basis sets consisting of atomic wavefunctions centred around the projectile ion only and around both of the colliding nuclei. The results are compared with experimental data from Belkacem et al (1997 Phys. Rev. A 56 2807).

EVOLUTION OF THE RELATIONSHIPS BETWEEN HELIUM ABUNDANCE, MINOR ION CHARGE STATE, AND SOLAR WIND SPEED OVER THE SOLAR CYCLE

International Nuclear Information System (INIS)

Kasper, J. C.; Stevens, M. L.; Korreck, K. E.; Maruca, B. A.; Kiefer, K. K.; Schwadron, N. A.; Lepri, S. T.

2012-01-01

The changing relationships between solar wind speed, helium abundance, and minor ion charge state are examined over solar cycle 23. Observations of the abundance of helium relative to hydrogen (A He ≡ 100 × n He /n H ) by the Wind spacecraft are used to examine the dependence of A He on solar wind speed and solar activity between 1994 and 2010. This work updates an earlier study of A He from 1994 to 2004 to include the recent extreme solar minimum and broadly confirms our previous result that A He in slow wind is strongly correlated with sunspot number, reaching its lowest values in each solar minima. During the last minimum, as sunspot numbers reached their lowest levels in recent history, A He continued to decrease, falling to half the levels observed in slow wind during the previous minimum and, for the first time observed, decreasing even in the fastest solar wind. We have also extended our previous analysis by adding measurements of the mean carbon and oxygen charge states observed with the Advanced Composition Explorer spacecraft since 1998. We find that as solar activity decreased, the mean charge states of oxygen and carbon for solar wind of a given speed also fell, implying that the wind was formed in cooler regions in the corona during the recent solar minimum. The physical processes in the coronal responsible for establishing the mean charge state and speed of the solar wind have evolved with solar activity and time.

Abundance and production of particle-associated bacteria and their role in a mangrove-dominated estuary

Digital Repository Service at National Institute of Oceanography (India)

DeSouza, M.J.B.D.; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

, Azam F (1982) Thymidine incorporation as a measure of heterotrophic bacterioplankton production in marine surface waters: evaluation and field results. Mar Biol 66:109-120 Fukuda R, Ogawa H, Nagata T, Koike I (1998) Direct determination of carbon... in the total and particle-associated bacterial abundance in the Mandovi estuary. TC - total counts, PAB - particle-associated bacteria. Gonsalves et al.: Particle-associated bacterial dynamics 21 0 200 400 600 800 1000 ONDJFMAMJJAS P r o duc t i o n...

Production of low axial energy spread ion beams with multicusp sources

Energy Technology Data Exchange (ETDEWEB)

Lee, Yung -Hee Y. [Univ. of California, Berkeley, CA (United States)

1998-05-01

Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.

Production of low axial energy spread ion beams with multicusp sources

International Nuclear Information System (INIS)

Lee, Y.H.Y.

1998-05-01

Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution

Fundamental processes determining the highly charged ion production in ECR ion sources

International Nuclear Information System (INIS)

Shirkov, G.D.

1992-01-01

The ion confinement and loss conditions in the open magnetic traps have been analyzed in this article. In EGRIS the the ions are confined in the negative potential well. The simultaneous application of ion cooling and pulse regime is proposed for pulse injection of highly charged ions in heavy ion accelerators and storage rings. 14 refs.; 3 figs

Production of ultrahigh ion current densities at skin-layer subrelativistic laser-plasma interaction

Energy Technology Data Exchange (ETDEWEB)

Badziak, J [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Glowacz, S [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Jablonski, S [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Parys, P [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Wolowski, J [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Hora, H [Department of Theoretical Physics, University of New South Wales, Sydney (Australia); Krasa, J [Institute of Physics, ASCR, Prague (Czech Republic); Laska, L [Institute of Physics, ASCR, Prague (Czech Republic); Rohlena, K [Institute of Physics, ASCR, Prague (Czech Republic)

2004-12-01

Some applications of fast ions driven by a short ({<=}1 ps) laser pulse (e.g. fast ignition of ICF targets, x-ray laser pumping, laboratory astrophysics research or some nuclear physics experiments) require ion beams of picosecond (or shorter) time durations and of very high ion current densities ({approx}10{sup 10} A cm{sup -2} or higher). A possible way of producing ion beams with such extreme parameters is ballistic focusing of fast ions generated by a target normal sheath acceleration (TNSA) mechanism at relativistic laser intensities. In this paper we discuss another method, where the production of short-pulse ion beams of ultrahigh current densities is possible in a planar geometry at subrelativistic laser intensities and at a low energy ({<=}1 J) of the laser pulse. This method-referred to as skin-layer ponderomotive acceleration (S-LPA)-uses strong ponderomotive forces induced at the skin-layer interaction of a short laser pulse with a proper preplasma layer in front of a solid target. The basic features of the high-current ion generation by S-LPA were investigated using a simplified theory, numerical hydrodynamic simulations and measurements. The experiments were performed with subjoule 1 ps laser pulses interacting with massive or thin foil targets at intensities of up to 2 x 10{sup 17} W cm{sup -2}. It was found that both in the backward and forward directions highly collimated high-density ion beams (plasma blocks) with current densities at the ion source (close to the target) approaching 10{sup 10} A cm{sup -2} are produced, in accordance with the theory and numerical calculations. These ion current densities were found to be comparable to (or even higher than) those estimated from recent short-pulse TNSA experiments with relativistic laser intensities. Apart from the simpler physics of the laser-plasma interaction, the advantage of the considered method is the low energy of the driving laser pulses allowing the production of ultrahigh

Defect production and subsequent effects induced by electronic energy loss of swift heavy ion

International Nuclear Information System (INIS)

Hou Mingdong; Liu Jie; Sun Youmei; Yin Jingmin; Yao Huijun; Duan Jinglai; Mo Dan; Zhang Ling; Chen Yanfeng; Chinese Academy of Sciences, Beijing

2008-01-01

Swift heavy ion in matter is one of forfront fields of nuclear physics in the world. A series of new phenomena were discovered in recent years. The history and sta- tus on the development of this field were reviewed. Electronic energy loss effects induced by swift heavy ion irradiation, such as defect production and evolution, ion latent track formation, phase transformation and anisotropy plastic deformation were introduced emphatically. A trend of future investigation was explored. (authors)

Optimizing hot-ion production from a gas-injected washer gun

International Nuclear Information System (INIS)

McCarrick, M.J.; Ellis, R.F.; Booske, J.H.; Koepke, M.

1987-01-01

This paper reports the results of a study to maximize the ion temperature of the plasma generated by a gas-injected washer gun. We characterize the gun discharge and the plasma output as a function of the controllable gun parameters. For hydrogen we find a maximum ion temperature of 100 eV with typical densities ranging from 2 x 10 11 to 5 x 10 12 cm -3 . A primary feature of the pulsed gun discharge is the observation of large amplitude rf fluctuations on the cathode voltage. The fluctuation amplitude varies with discharge current and with the quantity of injected gas. We show that the scaling of the fluctuation level with gun parameters is in agreement with that expected of an unstable beam-plasma system. We find a linear relation between the square of the fluctuation amplitude and the product of the plasma density times the ion temperature of the plasma output nT/sub i/, suggesting a stochastic wave-induced heating mechanism

Atomic physics and synchrotron radiation: The production and accumulation of highly charged ions

International Nuclear Information System (INIS)

Johnson, B.M.; Meron, M.; Agagu, A.; Jones, K.W.

1986-01-01

Synchrotron radiation can be used to produce highly-charged ions, and to study photoexcitation and photoionization for ions of virtually any element in the periodic table. To date, with few exceptions, atomic physics studies have been limited to rare gases and a few metal vapors, and to photoexcitation energies in the VUV region of the electromagnetic spectrum. These limitations can now be overcome using photons produced by high-brightness synchrotron storage rings, such as the x-ray ring at the National Synchrotron Light Source (NSLS) at Brookhaven. Furthermore, calculations indicate that irradiation of an ion trap with an intense energetic photon beam will result in a viable source of highly-charged ions that can be given the name PHOBIS: the PHOton Beam Ion Source. Promising results, which encourage the wider systematic use of synchrotron radiation in atomic physics research, have been obtained in recent experiments on VUV photoemission and the production and storage of multiply-charged ions. 26 refs., 4 figs., 1 tab

Atmospheric pressure chemical ionization studies of non-polar isomeric hydrocarbons using ion mobility spectrometry and mass spectrometry with different ionization techniques

Science.gov (United States)

Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.

2002-01-01

The ionization pathways were determined for sets of isomeric non-polar hydrocarbons (structural isomers, cis/trans isomers) using ion mobility spectrometry and mass spectrometry with different techniques of atmospheric pressure chemical ionization to assess the influence of structural features on ion formation. Depending on the structural features, different ions were observed using mass spectrometry. Unsaturated hydrocarbons formed mostly [M - 1]+ and [(M - 1)2H]+ ions while mainly [M - 3]+ and [(M - 3)H2O]+ ions were found for saturated cis/trans isomers using photoionization and 63Ni ionization. These ionization methods and corona discharge ionization were used for ion mobility measurements of these compounds. Different ions were detected for compounds with different structural features. 63Ni ionization and photoionization provide comparable ions for every set of isomers. The product ions formed can be clearly attributed to the structures identified. However, differences in relative abundance of product ions were found. Although corona discharge ionization permits the most sensitive detection of non-polar hydrocarbons, the spectra detected are complex and differ from those obtained with 63Ni ionization and photoionization. c. 2002 American Society for Mass Spectrometry.

Effects of sawtooth crashes on beam ions and fusion product tritons in JET

Energy Technology Data Exchange (ETDEWEB)

Marcus, F B; Hone, M A; Jarvis, O N; Loughlin, M J; Sadler, G [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Adams, J M; Bond, D S; Watkins, N [UKAEA Harwell Lab. (United Kingdom). Energy Technology Div.; Howarth, P J.A. [Birmingham Univ. (United Kingdom)

1994-07-01

The effect of a sawtooth crash on the radial distribution of the slowing down fusion product tritons and on beams ions, is examined with measurements of the 2.5 MeV and 14 MeV neutron emission line-integrals before and after sawtooth crashes. In deuterium discharges, the 14 MeV neutron production was wholly attributable to burnup of the 1 MeV fusion product tritons from d-d fusion. The local emissivity of 14 MeV neutrons, and hence of the profile of thermalizing tritons, is shown to be only weakly affected by crashes in the discharges studied. This is in contradiction with the apparent behaviour of injected beam ions as deduced from a study of the considerable changes in local emissivity of the 2.5 MeV neutrons. Nevertheless, the behaviour of the fusion product tritons is consistent with the scaling of the beam injected deuterium. 1 ref., 6 figs.

Effects of sawtooth crashes on beam ions and fusion product tritons in JET

International Nuclear Information System (INIS)

Marcus, F.B.; Hone, M.A.; Jarvis, O.N.; Loughlin, M.J.; Sadler, G.

1994-01-01

The effect of a sawtooth crash on the radial distribution of the slowing down fusion product tritons and on beams ions, is examined with measurements of the 2.5 MeV and 14 MeV neutron emission line-integrals before and after sawtooth crashes. In deuterium discharges, the 14 MeV neutron production was wholly attributable to burnup of the 1 MeV fusion product tritons from d-d fusion. The local emissivity of 14 MeV neutrons, and hence of the profile of thermalizing tritons, is shown to be only weakly affected by crashes in the discharges studied. This is in contradiction with the apparent behaviour of injected beam ions as deduced from a study of the considerable changes in local emissivity of the 2.5 MeV neutrons. Nevertheless, the behaviour of the fusion product tritons is consistent with the scaling of the beam injected deuterium. 1 ref., 6 figs

Inclusive b-jet production in heavy ion collisions at the LHC

Energy Technology Data Exchange (ETDEWEB)

Huang, Jinrui, E-mail: jinruih@lanl.gov; Kang, Zhong-Bo, E-mail: zkang@lanl.gov; Vitev, Ivan, E-mail: ivitev@lanl.gov

2013-10-07

Theoretical and experimental advances in understanding light jet production and modification in Pb + Pb reactions at √(s{sub NN})=2.76 TeV have been a highlight of the LHC heavy ion program. At the same time, the detailed mechanisms of heavy quark propagation and energy loss in dense QCD matter are not yet fully understood. With this motivation, we present theoretical predictions for the nuclear-induced attenuation of the differential cross section for inclusive b-jet production in heavy ion collisions at the LHC for comparison to upcoming data. We find that for transverse momenta p{sub T}≳75 GeV both hadronization and mass effects are negligible and this attenuation is comparable to the one observed for light jets. We discuss how the detailed b-jet quenching patterns can be used to gain new insight into the in-medium heavy flavor dynamics.

Entropy production in the relativistic heavy ion collisions

International Nuclear Information System (INIS)

Holme, A.K.; Csernai, L.P.; Levai, P.; Papp, G.

1989-09-01

A short overview is given on the most important possibilities of entropy production in the relativistic heavy ion collisions, which is connected to the shock phenomena. The E802 experiment is considered as an example, where one can determine the specific entropy content from measured strange particle ratios. The received large entropy value (S/N B ∼ 14) can be explained by assuming quark-gluon plasma formation. The possibility of overcooling of quark-gluon plasma and its deflagration are also investigated. (author) 22 refs.; 4 figs

Lepton-pair production by bremsstrahlung in central relativistic heavy ion collisions

International Nuclear Information System (INIS)

Lippert, T.; Becker, U.; Gruen, N.; Scheid, W.; Soff, G.

1988-03-01

We study the production of lepton-pairs by classical bremsstrahlung in central relativistic heavy-ion collisions. For the stopping of the nuclei we assume a simple model of point charges and a deceleration time. Pair creation probabilities are calculated in first order perturbation theory. (orig.)

Pion production in relativistic heavy ion collisions

International Nuclear Information System (INIS)

Norbury, J.W.

1983-01-01

A Lorentz-invariant differential cross section for pion production in peripheral, relativistic, heavy ion collisions is calculated for the collisions of an 16 O projectile onto a 12 C target. The pions are produced via excitations of a Δ(3,3) resonant state in the projectile with simultaneous excitation of an M1 giant resonance in the target. A second order amplitude describing resonance formation and decay is derived within the context of second order, time-dependent perturbation theory and a corresponding transition rate is evaluated. This is then applied to the problem of pion production and a differential cross section is calculated using a simple product-of-states model. The whole theory is then re-formulated within a second quantized particle-hole model which describes the basic process of M1 giant resonance formation as well as the formation and decay of the intermediate Δ(3,3) resonance. Subsequently, a new Lorentz-invariant differential cross section is calculated from the particle-hole amplitude. The theoretical cross section is compared with some experimental data and the agreement is found to be satisfactory given the nature of the data and the assumptions of the theory

Multiple electromagnetic electron-positron pair production in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Alscher, A.; Hencken, K.; Trautmann, D.; Baur, G.

1997-01-01

We calculate the cross sections for the production of one and more electron-positron pairs due to the strong electromagnetic fields in relativistic heavy-ion collisions. We derive the N-pair amplitude using the generating functional of fermions in an external field and the path-integral formalism. The N-pair production probability is found to be an approximate Poisson distribution. We calculate total cross sections for the production of one pair in lowest order, including corrections from the Poisson distribution up to third order. Furthermore, we calculate cross sections for the production of up to five pairs including corrections from the Poisson distribution. copyright 1997 The American Physical Society

The production of accelerated radioactive ion beams

International Nuclear Information System (INIS)

Olsen, D.K.

1993-01-01

During the last few years, substantial work has been done and interest developed in the scientific opportunities available with accelerated radioactive ion beams (RIBs) for nuclear physics, astrophysics, and applied research. This interest has led to the construction, development, and proposed development of both first- and second-generation RIB facilities in Asia, North America, and Europe; international conferences on RIBs at Berkeley and Louvain-la-Neuve; and many workshops on specific aspects of RIB production and science. This paper provides a discussion of both the projectile fragmentation, PF, and isotope separator on-line, ISOL, approach to RIB production with particular emphasis on the latter approach, which employs a postaccelerator and is most suitable for nuclear structure physics. The existing, under construction, and proposed facilities worldwide are discussed. The paper draws heavily from the CERN ISOLDE work, the North American IsoSpin Laboratory (ISL) study, and the operating first-generation RIB facility at Louvain-la-Neuve, and the first-generation RIB project currently being constructed at ORNL

Dynamics of atoms-ions transformation processes in the radioactive ion production systems ISOL

International Nuclear Information System (INIS)

Jardin, Pascal

2013-01-01

The aims of this work were 1)to study the effect of diffusion, effusion and ionization processes in the atom-ion transformation, 2)to better understand the temporal behaviour of ISOL devices and to apply it to the developments of the ISOL production systems. These aims were partially reached: the results obtained with 'ECS ECR' of SPIRAL 1 and SPIRAL 2 and their confrontation have allowed to analytically described their temporal behaviour and to reveal under which conditions it is possible to consider the processes of diffusion, effusion and ionization as separable processes and consequently to consider them as consecutive. (O.M.) [fr

Investigation into the behavior of metal-argon polyatomic ions (MAr+) in the extraction region of inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Ebert, Chris H.; Witte, Travis M.; Houk, R.S.

2012-01-01

The abundances of metal-argon polyatomic ions (MAr + ) are determined in inductively coupled plasma-mass spectrometry (ICP-MS). The ratios of MAr + abundance to that for M + ions are measured experimentally. These ratios are compared to expected values, calculated for typical plasma conditions using spectroscopic data. For all metals studied (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn), the measured ratios are significantly lower than the calculated ratios. Increasing the plasma potential (and thereby increasing the ion kinetic energy) by means of a homemade guard electrode with a wide gap further reduces the MAr + /M + ratio. Implementing a skimmer cone designed for high transmission of light ions increases the MAr + abundance. Considering this evidence, the scarcity of MAr + ions is attributed to collision induced dissociation (CID), likely due to a shock wave at the tip of or in the throat of the skimmer cone. - Highlights: ► MAr + ions are less abundant in the mass spectrum than expected from the ICP. ► Increasing the plasma potential reduces their abundance further. ► The extraction lens voltage does not greatly affect the MAr + abundances. ► The weakly-bound MAr + ions are probably dissociated by collisions during extraction.

New electron-ion-plasma equipment for modification of materials and products surface

International Nuclear Information System (INIS)

Koval', N.N.

2013-01-01

Electron-ion-plasma treatment of materials and products, including surface clearing and activation, formation surface layers with changed chemical and phase structure, increased hardness and corrosion resistance; deposition of various functional coatings, has received a wide distribution in a science and industry. Widespread methods of ion-plasma modification of material and product surfaces are ion etching and activation, ion-plasma nitriding, arc or magnetron deposition of functional coatings, including nanostructured. The combination of above methods of surface modification allows essentially to improve exploitation properties of treated products and to optimize the characteristics of modified surfaces for concrete final requirements. For the purpose of a combination of various methods of ion-plasma treatment in a single work cycle at Institute of High Current Electronics of SB RAS (IHCE SB RAS) specialized technological equipment 'DUET', 'TRIO' and 'QUADRO' and 'KVINTA' have been developed. This equipment allow generating uniform low-temperature gas plasma at pressures of (0.1-1) Pa with concentration of (10 9 -10 11 ) cm -3 in volume of (0.1-1) m 3 . In the installations consistent realization of several various operations of materials and products treatment in a single work cycle is possible. The operations are preliminary heating and degassing, ion clearing, etching and activation of materials and products surface by plasma of arc discharges; chemicothermal treatment (nitriding) for formation of diffusion layer on a surface of treated sample using plasma of nonself-sustained low-pressure arc discharge; deposition of single- or multilayered superhard (≥40 GPa) nanocrystalline coatings on the basis of pure metals or their compounds (nitrides, carbides, carbonitrides) by the arc plasma-assisted method. For realization of the modes all installations are equipped by original sources of gas and metal plasma. Besides, in

Structure and dynamics of highly charged heavy ions studied with the electron beam ion trap in Tokyo

International Nuclear Information System (INIS)

Nakamura, Nobuyuki; Hu, Zhimin; Watanabe, Hirofumi; Li, Yueming; Kato, Daiji; Currell, Fred J.; Tong Xiaomin; Watanabe, Tsutomu; Ohtani, Shunsuke

2011-01-01

In this paper, we present the structure and the dynamics of highly charged heavy ions studied through dielectronic recombination (DR) observations performed with the Tokyo electron beam ion trap. By measuring the energy dependence of the ion abundance ratio in the trap at equilibrium, we have observed DR processes for open shell systems very clearly. Remarkable relativistic effects due to the generalized Breit interaction have been clearly shown in DR for highly charged heavy ions. We also present the first result for the coincidence measurement of two photons emitted from a single DR event.

Strangeness production in heavy ion collisions

International Nuclear Information System (INIS)

Redlich, K.

2001-05-01

Strangeness production in heavy ion collisions is discussed in a broad energy range from SIS to RHIC. In the whole energy range particle yields are showing high level of chemical equilibration which can be described by the unified freezeout conditions of fixed energy/particle ≅ 1GeV. The statistical model within the canonical formulation of strangeness conservation provides a framework to describe the observed enhancement of (multi)strange particles from p+A to A+A collisions measured at the SPS energy and predicts that this enhancement should be larger for decreasing collision energy. However, only at the SPS and RHIC chemical freezeout temperature is consistent within error with the critical value required for deconfinement and simultaneously strangeness is uncorrelated and distributed in the whole volume of the fireball. (orig.)

Ion sources development at GANIL for radioactive beams and high charge state ions

International Nuclear Information System (INIS)

Leroy, R.; Barue, C.; Canet, C.; Dupuis, M.; Flambard, J.L.; Gaubert, G.; Gibouin, S.; Huguet, Y.; Jardin, P.; Lecesne, N.; Leherissier, P.; Lemagnen, F.; Pacquet, J.Y.; Pellemoine-Landre, F.; Rataud, J.P.; Saint-Laurent, M.G.; Villari, A.C.C.; Maunoury, L.

2001-01-01

The GANIL laboratory has in charge the production of ion beams for nuclear and non nuclear physics. This article reviews the last developments that are underway in the fields of radioactive ion beam production, increase of the metallic ion intensities and production of highly charges ion beams. (authors)

Increased reactive oxygen species production and lower abundance of complex I subunits and carnitine palmitoyltransferase 1B protein despite normal mitochondrial respiration in insulin-resistant human skeletal muscle.

Science.gov (United States)

Lefort, Natalie; Glancy, Brian; Bowen, Benjamin; Willis, Wayne T; Bailowitz, Zachary; De Filippis, Elena A; Brophy, Colleen; Meyer, Christian; Højlund, Kurt; Yi, Zhengping; Mandarino, Lawrence J

2010-10-01

The contribution of mitochondrial dysfunction to skeletal muscle insulin resistance remains elusive. Comparative proteomics are being applied to generate new hypotheses in human biology and were applied here to isolated mitochondria to identify novel changes in mitochondrial protein abundance present in insulin-resistant muscle. Mitochondria were isolated from vastus lateralis muscle from lean and insulin-sensitive individuals and from obese and insulin-resistant individuals who were otherwise healthy. Respiration and reactive oxygen species (ROS) production rates were measured in vitro. Relative abundances of proteins detected by mass spectrometry were determined using a normalized spectral abundance factor method. NADH- and FADH(2)-linked maximal respiration rates were similar between lean and obese individuals. Rates of pyruvate and palmitoyl-DL-carnitine (both including malate) ROS production were significantly higher in obesity. Mitochondria from obese individuals maintained higher (more negative) extramitochondrial ATP free energy at low metabolic flux, suggesting that stronger mitochondrial thermodynamic driving forces may underlie the higher ROS production. Tandem mass spectrometry identified protein abundance differences per mitochondrial mass in insulin resistance, including lower abundance of complex I subunits and enzymes involved in the oxidation of branched-chain amino acids (BCAA) and fatty acids (e.g., carnitine palmitoyltransferase 1B). We provide data suggesting normal oxidative capacity of mitochondria in insulin-resistant skeletal muscle in parallel with high rates of ROS production. Furthermore, we show specific abundance differences in proteins involved in fat and BCAA oxidation that might contribute to the accumulation of lipid and BCAA frequently associated with the pathogenesis of insulin resistance.

A Au82Si18 liquid metal field-ion emitter for the production of Si ions: fundamental properties and mechanisms

International Nuclear Information System (INIS)

Bischoff, L.; Mair, G.L.R.; Aidinis, C.J.; Londos, C.A.; Akhmadaliev, C.; Ganetsos, Th.

2004-01-01

Focused silicon beams are useful for direct write applications, e.g., lithography on silicon without the undesirable effect of substrate contamination. However, since pure silicon is not amenable to liquid metal ion source (LMIS) manufacture, a suitable alloy containing silicon has to be produced. This paper covers almost all fundamental aspects of a Au 82 Si 18 eutectic, including the most detailed beam mass spectra reported to date of a AuSi source. A finding worthy of note in this investigation, manifested in the behaviour of the ion extraction voltage with temperature, is the abnormal behaviour of the surface tension coefficient of the alloy with temperature. An important deduction from this work, however, concerns the mechanisms responsible for the creation of doubly charged ions: reasons of self-consistency indicate that while Si 2+ is directly field evaporated, Au 2+ must form by the post-ionization of Au + . Finally, two different mechanisms seem to co-exist, as far as the production of cluster ions is concerned. While for cluster ions containing only a few atoms some sort of surface field-ionization mechanism might be responsible for their creation, for larger clusters, a droplet break-up mechanism, possibly by ion capture, seems very likely

Ischemia - reperfusion induced changes in levels of ion transport proteins in gerbil brain

International Nuclear Information System (INIS)

Lehotsky, J.; Racay, P.; Kaplan, P.; Mezesova, V.; Raeymaekers, L.

1998-01-01

A quantitative Western blotting was used to asses the levels of ion transport proteins in gerbil brain in control and in animals after ischemic-reperfusion injury (IRI). The gene products of plasma membrane Ca 2+ pump (PMCA) were detected in the hippocampus, cerebral cortex and cerebellum. However, they showed a distinct distribution pattern. Inositol 1,4,5-triphosphate (Ins 3 ) receptor and reticular Ca 2+ pump are the most abundant in cerebellum and hippocampus. The IRI leads to a selective decrease in content of PMCA and InsP 3 receptor I isoforms. The levels of α 3 isoform of Na + pump and reticular proteins: Ca 2+ pump and calreticulin remained constant. InsP 3 receptor and organellar Ca 2+ (SERCA) are the most abundant in cerebellum and hippocampus. Ischemia and reperfusion up to 10 days leads to a signal decrease of PMCA immuno-signal. We suppose that alteration of number of ion transport proteins, can contribute to changes which participate or follow the delayed death of neurons in hippocampus. (authors)

Effect of pion mean-field on properties of pions and kaons from heavy-ion collisions

International Nuclear Information System (INIS)

Zheng Yuming; Chu Zili; Wang Hui; Sa Benhao

1996-01-01

The Relativistic Vlasov-Uehling-Uhlenbeck (RVUU) model is used to study the properties of pions and kaons produced in heavy ion collisions. We include the nuclear medium effect on kaon and pion in the model, and simulate pion production and subthreshold kaon production in Kr + Zr reactions at 1 GeV/u. The calculated results show that the attractive pion optical potential changes the final-state pion momentum spectrum, enhancing the yield of pions with low transverse momenta. At the same time it also increases the kaon abundance and modifies the kaon momentum distribution

Measurement of quarkonia production in heavy-ion collisions with the ATLAS detector

CERN Document Server

Tapia Araya, Sebastian; The ATLAS collaboration

2017-01-01

The suppression of heavy quarkonia states in heavy-ion collisions is a phenomenon understood as a consequence of QGP formation in the hot, dense system produced in interactions of heavy ions at high energy. In addition to hot matter effects, cold nuclear effects can play an important role in quarkonia production. Therefore, a full assessment of different physics scenarios requires detailed studies on the effects present in Pb+Pb and p+Pb collisions in comparison to the pp collisions. Results of the studies based on p+Pb data collected in 2013 and pp and Pb+Pb data collected in 2015 at the LHC by the ATLAS experiment at the centre of mass energy of 5.02 TeV allowed studying prompt and non-prompt J/ψ and ψ(2S) productions as well as Υ(nS) (n = 1, 2, 3) production via the di-muon decay final states. The results of the measurements presented as a function rapidity and transverse momentum as well as the ratios between different species and systems are presented and discussed in the talk.

Production of AlN films: ion nitriding versus PVD coating

International Nuclear Information System (INIS)

Figueroa, U.; Salas, O.; Oseguera, J.

2004-01-01

The properties of AlN render this material very attractive for optical, electronic, and tribological applications; thus, a great interest exists for the production of thin AlN films on a variety of substrates. Many methods have been developed for this purpose where two processes stand out: plasma-assisted nitriding (PAN) and PVD coating. In the present paper, we compare the processing advantages and disadvantages of both methods in terms of the characteristics of the layers formed. AlN production by ion nitriding is very sensitive to presputtering cleaning and working pressure. Layers several micrometers thick can be produced in a few hours, which are formed by a fine mixture of Al+AlN. The surface morphology of the layers is rather rough. On the other hand, formation of PVD AlN coatings by DC reactive magnetron sputtering is more readily performed and better controlled than in ion nitriding. PVD results in macroscopically smoother AlN films and with similar thickness than the ion nitrided layers but produced in shorter processing times. The morphology of the PVD AlN layers is columnar with a fairly flat surface. Mechanisms for the formation of both types of AlN layers are proposed. One of the main differences between the two processes that explain the different AlN layer morphologies is the energy of the particles that arrive at the substrate. Considering only the processing advantages and the morphology of the AlN layers formed, PVD performs better than PAN processing

Mutation of Blakeslea trispora in lycopene production by ion beams

International Nuclear Information System (INIS)

Zhang Ning; Yu Long; Shen Yiling

2008-01-01

In this paper the mutation of lycopene producing strain, B. trispora(-) by use of low energy N + ion implantation, was studied. Experimental results show that higher mutation rate and wider mutation spectrum have been obtained after B. trispora (-) being implanted and four lycopene high yielding strains B. trispora (-) BH3-701 et al have been screened out. It has been found that the average production of lycopene increases by 50% compared with that of original strain after five passages in shaking flasks. The highest yield strain BH3-701 can accumulate lycopene in the later stage and increase production efficiency greatly. (authors)

Diffusion and mobility of positive ions in sulphur hexafluoride

International Nuclear Information System (INIS)

Urquijo, J. de; Alvarez, I.; Cisneros, C.; Martinez, H.

1988-01-01

It is presented some recent results on the measurements of longitudinal difusion and mobility of positive ions in SF 6 . The experimental technique employed could determine the most abundant positive ion under electric discharge conditions. (A.C.A.S.) [pt

Molecular and negative ion production by a standard electron cyclotron resonance ion source

Energy Technology Data Exchange (ETDEWEB)

Racz, R. [Institute of Nuclear Research (ATOMKI), Bem ter 18/c, H-4026 Debrecen (Hungary); University of Debrecen, Egyetem ter 1, H-4010 Debrecen (Hungary); Biri, S.; Juhasz, Z.; Sulik, B. [Institute of Nuclear Research (ATOMKI), Bem ter 18/c, H-4026 Debrecen (Hungary); Palinkas, J. [University of Debrecen, Egyetem ter 1, H-4010 Debrecen (Hungary)

2012-02-15

Molecular and negative ion beams, usually produced in special ion sources, play an increasingly important role in fundamental and applied atomic physics. The ATOMKI-ECRIS is a standard ECR ion source, designed to provide highly charged ion (HCI) plasmas and beams. In the present work, H{sup -}, O{sup -}, OH{sup -}, O{sub 2}{sup -}, C{sup -}, C{sub 60}{sup -} negative ions and H{sub 2}{sup +}, H{sub 3}{sup +}, OH{sup +}, H{sub 2}O{sup +}, H{sub 3}O{sup +}, O{sub 2}{sup +} positive molecular ions were generated in this HCI-ECRIS. Without any major modification in the source and without any commonly applied tricks (such as usage of cesium or magnetic filter), negative ion beams of several {mu}A and positive molecular ion beams in the mA range were successfully obtained.

Possibility of sorption purification of chromium comprising waste waters of galvanic production by inorganic ion exchangers

International Nuclear Information System (INIS)

Khaynakov, S.A.; Likov, E.P.; Bortun, A.I.; Belyukov, V.N.

1986-01-01

Present work is devoted to possibilities of sorption purification of chromium comprising waste waters of galvanic production by inorganic ion exchangers. Thus, the comparative study of sorption of chromium ions on anion exchanger A B-17 and on inorganic ion exchangers on the basis of hydrated titanium and zirconium dioxides in static and dynamic conditions is conducted. The influence of chromium ions concentration, solutions acidity (ph=1÷12) and presence of base electrolyte on sorption is studied. The state of chromium ions sorbed by inorganic ion exchangers is studied by means of infrared spectroscopy and spectroscopy. It is defined that inorganic sorbents could be used for chromium extraction from different solutions.

Chinook Abundance - Linear Features [ds181

Data.gov (United States)

California Natural Resource Agency — The dataset 'ds181_Chinook_ln' is a product of the CalFish Adult Salmonid Abundance Database. Data in this shapefile are collected from stream sections or reaches...

An enhanced production of highly charged ions in the ECR ion sources

International Nuclear Information System (INIS)

Schaechter, L.; Dobrescu, S.; Badescu- Singureanu, Al.I.; Stiebing, K.E.; Runkel, S.; Hohn, O.; Schmidt, L.; Schempp, A.; Schmidt - Boecking, H.

2000-01-01

The electron cyclotron resonance (ECR) ion source (ECRIS) are the ideal sources of highly charged heavy ions. Highly charged heavy ions are widely used in atomic physics research where they constitute a very efficient tool due to their very high electric potential of collision. The highly charged ions are also used in fusion plasma physics studies, in solid state surface physics investigations and are very efficient when injected in particle accelerators. More than 50 ECR ion sources are presently working in the whole world. Stable and intense highly charged heavy ions beams are extracted from ECR ion sources, in a wide range of ion species. RECRIS, the Romanian 14 GHz ECR Ion Source, developed in IFIN-HH, designed as a facility for atomic physics and materials studies, has been recently completed. The research field concerning the development of advanced ECRIS and the study of the physical processes of the ECR plasma are presently very dynamical , a fact well proved by the great number of scientific published works and the numerous dedicated international conferences and workshops. It is well established that the performance of ECRIS can substantially be enhanced if special techniques like a 'biased disk' or a special wall coating of the plasma chamber are employed. In the frame of a cooperation project between IFIN-HH ,Bucharest, Romania and the Institut fuer Kernphysik of the J. W. Goethe University, Frankfurt/Main, Germany we developed, on the basis of previous research carried out in IFIN-HH, a new method to strongly increase the intensity of the ion beams extracted from the 14.4 GHz ECRIS in Frankfurt. In our method a special metal-dielectric structure (MD cylinder) was introduced in the ECRIS plasma chamber. In the experiment analyzed beams of Ar 16+ ions were increased in intensity by a factor of 50 as compared to the standard set up with stainless steel chamber. These results have been communicated at the International Conference on Ion Sources held at

Processes of hypernuclei formation in relativistic ion collisions

Science.gov (United States)

Botvina, Alexander; Bleicher, Marcus

2018-02-01

The study of hypernuclei in relativistic ion collisions open new opportunities for nuclear and particle physics. The main processes leading to the production of hypernuclei in these reactions are the disintegration of large excited hyper-residues (target- and projectile-like), and the coalescence of hyperons with other baryons into light clusters. We use the transport, coalescence and statistical models to describe the whole reaction, and demonstrate the effectiveness of this approach: These reactions lead to the abundant production of multi-strange nuclei and new hypernuclear states. A broad distribution of predicted hypernuclei in masses and isospin allows for investigating properties of exotic hypernuclei, as well as the hypermatter both at high and low temperatures. There is a saturation of the hypernuclei production at high energies, therefore, the optimal way to pursue this experimental research is to use the accelerator facilities of intermediate energies, like FAIR (Darmstadt) and NICA (Dubna).

Ammonia abundances in comets

Science.gov (United States)

Wyckoff, S.; Tegler, S.; Engel, L.

The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

The ISO spectrum of the planetary nebula NGC 6302 - II. Nebular abundances

NARCIS (Netherlands)

Pottasch, [No Value; Beintema, DA

The ISO spectrum of NGC 6302 is used, in conjunction with the visible and ultraviolet spectrum, to determine the nebular composition. In addition to being considerably more accurate than previous determinations, the abundances of many more elements (and ions) can be found. A discussion of the

How ants drop out: ant abundance on tropical mountains.

Science.gov (United States)

Longino, John T; Branstetter, Michael G; Colwell, Robert K

2014-01-01

In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops.

How ants drop out: ant abundance on tropical mountains.

Directory of Open Access Journals (Sweden)

John T Longino

Full Text Available In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica and examined the impact of elevation (as a proxy for temperature and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops.

AMS of heavy elements with an ECR ion source and the ATLAS linear accelerator

CERN Document Server

Paul, M; Ahmad, I; Borasi, F; Caggiano, J; Davids, C N; Greene, J P; Harss, B; Heinz, A; Henderson, D J; Henning, W F; Jiang, C L; Pardo, R C; Rehm, K E; Rejoub, R; Seweryniak, D; Sonzogni, A; Uusitalo, J; Vondrasek, R C

2000-01-01

Detection of heavy elements by accelerator mass spectrometry with the electron cyclotron resonance ion source, Argonne linear accelerator and fragment mass analyzer (ECRIS-ATLAS-FMA) system has been developed. The use of the ECR-ATLAS system for AMS of heavy elements has two interesting features: (i) the efficient production of high-charge state ions in the ECR source ensures the elimination of molecular ions at the source stage, a highly attractive feature for any mass-spectrometric use not exploited so far; (ii) the linear acceleration based on velocity matching and the beam transport system act as a powerful mass filter for background suppression. We have shown that our system reaches an abundance sensitivity of 1x10 sup - sup 1 sup 4 for Pb isotopes. The sup 2 sup 3 sup 6 U detection sensitivity is sup 2 sup 3 sup 6 U/U > or approx. 1x10 sup - sup 1 sup 2 , limited mainly by the ion source output.

Practical application of in silico fragmentation based residue screening with ion mobility high-resolution mass spectrometry.

Science.gov (United States)

Kaufmann, Anton; Butcher, Patrick; Maden, Kathry; Walker, Stephan; Widmer, Mirjam

2017-07-15

A screening concept for residues in complex matrices based on liquid chromatography coupled to ion mobility high-resolution mass spectrometry LC/IMS-HRMS is presented. The comprehensive four-dimensional data (chromatographic retention time, drift time, mass-to-charge and ion abundance) obtained in data-independent acquisition (DIA) mode was used for data mining. An in silico fragmenter utilizing a molecular structure database was used for suspect screening, instead of targeted screening with reference substances. The utilized data-independent acquisition mode relies on the MS E concept; where two constantly alternating HRMS scans (low and high fragmentation energy) are acquired. Peak deconvolution and drift time alignment of ions from the low (precursor ion) and high (product ion) energy scan result in relatively clean product ion spectra. A bond dissociation in silico fragmenter (MassFragment) supplied with mol files of compounds of interest was used to explain the observed product ions of each extracted candidate component (chromatographic peak). Two complex matrices (fish and bovine liver extract) were fortified with 98 veterinary drugs. Out of 98 screened compounds 94 could be detected with the in silico based screening approach. The high correlation among drift time and m/z value of equally charged ions was utilized for an orthogonal filtration (ranking). Such an orthogonal ion mobility based filter removes multiply charged ions (e.g. peptides and proteins from the matrix) as well as noise and artefacts. Most significantly, this filtration dramatically reduces false positive findings but hardly increases false negative findings. The proposed screening approach may offer new possibilities for applications where reference compounds are hardly or not at all commercially available. Such areas may be the analysis of metabolites of drugs, pyrrolizidine alkaloids, marine toxins, derivatives of sildenafil or novel designer drugs (new psychoactive substances

Cation mobility in H+/Na+ ion exchange products of acid tantalum and zirconium phosphates

International Nuclear Information System (INIS)

Tarnopol'skij, V.A.; Yaroslavtsev, A.B.

2000-01-01

Ionic conductivity of Na + /H + exchange products on acid zirconium phosphate with different substitution degree and on acid tantalum phosphate, where ion exchange occurs via formation of a continuous series of solid solutions, was studied by the method of conductometry. It was ascertained that ionic conductivity decreases monotonously with growth in substitution degree of H + for Na + in acid tantalum phosphate. Anomalous increase in ionic conductivity of ion exchange products on acid zirconium phosphate with a low substitution degree has been detected for the first time. Formation of a double electric layer with a high concentration of cationic defects on the interface surface is the reason for increase in ionic conductivity [ru

Seasonal to hour variation scales in abundance and production of total and particle-attached bacteria in the open NW Mediterranean Sea (0–1000 m

Directory of Open Access Journals (Sweden)

G. Mével

2008-11-01

Full Text Available We present the vertical and temporal dynamics of total vs. particle-attached bacterial abundance and activity over a 5 week period under summer to autumn transition in NW Mediterranean Sea. At a weekly time scale, total bacterial biomass and production in the euphotic layers was significantly correlated with phytoplanktonic biomass. At an hourly time scale, total bacterial biomass responded very rapidly to chlorophyll a fluctuations, suggesting a tight coupling between phytoplankton and bacteria for resource partitioning during the summer-autumn transition. In contrast, no influence of diel changes on bacterial parameters was detected. Episodic events such as coastal water intrusions had a significant positive effect on total bacterial abundance and production, whereas we could not detect any influence of short wind events whatever the magnitude. Finally, we show that particle-attached bacteria can represent a large proportion (up to 49% of the total bacterial activity in the euphotic layer but display rapid and sporadic changes at hourly time scales. In the mesopelagic layers, bacterial abundance and production linearly decreased with depth, except some production peaks at 400–750 m. This study underlines the value of large datasets covering different temporal scales to clarify the biogeochemical role of bacteria in the cycling of organic matter in open seawater.

Reactions of atomic oxygen with the chlorate ion and the perchlorate ion

Science.gov (United States)

Anan'ev, Vladimir; Miklin, Mikhail; Kriger, Ludmila

2014-06-01

The reactions of the chlorate ion with atomic oxygen formed under photolysis of the nitrate ion introduced to potassium chlorate crystal by co-crystallization were studied by optical and infrared absorption spectroscopy. The perchlorate ion was found to form in solids as product of addition reaction of singlet atomic oxygen, formed under dissociation of the peroxynitrite ion - the product of isomerization of the excited nitrate ion. Triplet atomic oxygen does not react with the chlorate ion. The atomic oxygen formed under photolysis of the nitrate ion introduced to potassium perchlorate crystal by co-crystallization does not react with the perchlorate ion.

Numerical simulation of ion production processes in EBIS

International Nuclear Information System (INIS)

Kalagin, I.V.; Ovsyannikov, V.P.

1996-01-01

The numerical model of EBIS is presented. The calculation of Kr ionization by cooling with Ne ions was carried out taking into account charge exchange, ion heating by electrons, ion-ion energy exchange and ion escape processes. A good agreement with experimental data was observed. 19 refs., 13 figs

Abundance and distribution of Macrolide-Lincosamide-Streptogramin resistance genes in an anaerobic-aerobic system treating spiramycin production wastewater.

Science.gov (United States)

Liu, Miaomiao; Ding, Ran; Zhang, Yu; Gao, Yingxin; Tian, Zhe; Zhang, Tong; Yang, Min

2014-10-15

The behaviors of the Macrolide-Lincosamide-Streptogramin (MLS) resistance genes were investigated in an anaerobic-aerobic pilot-scale system treating spiramycin (SPM) production wastewater. After screening fifteen typical MLS resistance genes with different mechanisms using conventional PCR, eight detected genes were determined by quantitative PCR, together with three mobile elements. Aerobic sludge in the pilot system exhibited a total relative abundance of MLS resistance genes (per 16S rRNA gene) 2.5 logs higher than those in control samples collected from sewage and inosine wastewater treatment systems (P resistance genes. However, the total relative gene abundance in anaerobic sludge (4.3 × 10(-1)) was lower than that in aerobic sludge (3.7 × 10(0)) despite of the higher SPM level in anaerobic reactor, showing the advantage of anaerobic treatment in reducing the production of MLS resistance genes. The rRNA methylase genes (erm(B), erm(F), erm(X)) were the most abundant in the aerobic sludge (5.3 × 10(-1)-1.7 × 10(0)), followed by esterase gene ere(A) (1.3 × 10(-1)) and phosphorylase gene mph(B) (5.7 × 10(-2)). In anaerobic sludge, erm(B), erm(F), ere(A), and msr(D) were the major ones (1.2 × 10(-2)-3.2 × 10(-1)). These MLS resistance genes (except for msr(D)) were positively correlated with Class 1 integron (r(2) = 0.74-0.93, P < 0.05), implying the significance of horizontal transfer in their proliferation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Abundances in very metal-poor stars

Science.gov (United States)

Johnson, Jennifer Anne

We measured the abundances of 35 elements in 22 field red giants and a red giant in the globular cluster M92. We found the [Zn/Fe] ratio increases with decreasing [Fe/H], reaching ~0.3 at [Fe/H] = -3.0. While this is a larger [Zn/Fe] than found by previous investigators, it is not sufficient to account for the [Zn/Fe] observed in the damped Lyα systems. We test different models for the production of the s-process elements by comparing our [Y/Zr] values, which have been produced by the r- process, to predictions of what the s-process does not produce. We find that the models of Arlandini et al. (1999), which calculate s-process production in a model AGB star, agree the best. We then look at the r-process abundances across a wide range in mass. The [Y/Ba] values for most of our stars cluster around -0.30, but there are three outliers with [Y/Ba] values up to 1 dex higher. Thus the heavy element abundances do not show the same pattern from Z = 39 to Z = 56. However, our abundances ratios from Pd (Z = 46) to Yb (Z = 70) are consistent with a scaled solar system r- process pattern, arguing that at least the heavy r- process elements are made in a universal pattern. If we assume that this same pattern hold through thorium, we can determine the ages of our stars from the present abundance of radioactive thorium and an initial thorium abundance based on the abundance of stable heavy elements. Our results for five stars are consistent with those stars being the same age. Our mean age is 10.8 +/- 2 Gyr. However that result depends critically on the assumed Th/stable ratio, which we adopt from models of the r-process. For an average age of 15 Gyrs, the initial Th/Eu ratio we would need is 0.590. Finally, the [element/Fe] ratios for elements in the iron group and lower do not show any dispersion, unlike for the r- process elements such as Y and Ba. Therefore the individual contributions of supernovae have been erased for the lighter elements.

Ion-microprobe measurements of Mg, Ca, Ti and Fe isotopic ratios and trace element abundance in hibonite-bearing inclusions in primitive meteorites

International Nuclear Information System (INIS)

Fahey, A.J.

1988-01-01

This thesis reports the isotopic abundances of Mg, Ca, and Ti and rare earth element (REE) abundances in 19 hibonite-bearing inclusions from primative meteorites. The isotopic ratios of Fe were measured in one of the samples, Lance HH-1. These measurements were made by means of secondary ion mass spectrometry (CAMECA IMS-3f). The novel hardware and software developments that made this work possible are described in detail. The samples were studied in thin section in order to investigate the relationship between the inclusions and their mineralogical environments. Inclusions from a number of different meteorites, specifically, Mighei, Murray, Murchison, Lance, Efremovka, Vigarano, Qingzhen, Dhajala, and Semarkona, were studied. The isotopes of Ca and Ti show large and correlated abundance anomalies in their most neutron-rich isotopes, 48 Ca and 50 Ti. The largest anomalies among the samples studied here are in the Murray inclusion MY-F6, with a 4.6% deficit in 48 Ca and a 5.2% deficit in 50 Ti, and Lance HH-1, with 3.3% and 6.0% deficits in 48 Ca and 50 Ti respectively. Correlated excesses of 48 Ca and 50 Ti, up to 2.4% and 1.4% respectively, are found in some other samples studied here. The fact that there is a correlation of isotopic anomalies in two different elements is clear evidence for a nucleosynthetic origin of these effects. Various possibilities for the origin of these isotopic anomalies are discussed and it is shown that a Cosmic Chemical Memory-like model of the incomplete mixing of dust grains from one or several supernovae is sufficient to explain the data. Magnesium isotopes show excesses of 26 Mg, attributable to the in-situ decay of 26 Al, in 7 of these inclusions

Ion source based on Penning discharge for production of doubly charged helium ions

Directory of Open Access Journals (Sweden)

V. I. Voznyi

2017-11-01

Full Text Available The article presents the results of operation of ion source with Penning discharge developed in the IAP of NAS of Ukraine to produce doubly charged helium ions He2+ beam and to increase the energy of accelerated ions up to 3.2 MeV. This energy is necessary for ERDA channel when measuring hydrogen concentration in the structural materials used in nuclear engineering. The ion source parameters are the following: discharge voltage is 6 kV, discharge current is 0.8 - 1.2 mA, the current of singly charged helium ions He+ 24 μA, the current of doubly charged helium ions He2+ 0.5 μA.

Large amounts of antiproton production by heavy ion collision

International Nuclear Information System (INIS)

Takahashi, Hiroshi; Powell, J.

1987-01-01

To produce large amounts of antiprotons, on the order of several grams/year, use of machines to produce nuclear collisions are studied. These can be of either proton-proton, proton-nucleus and nucleus-nucleus in nature. To achieve high luminosity colliding beams, on the order of 10 41 m/cm 2 , a self-colliding machine is required, rather than a conventional circular colliding type. The self-colliding machine can produce additional antiprotons through successive collisions of secondary particles, such as spectator nucleons. A key problem is how to collect the produced antiprotons without capture by beam nuclei in the collision zone. Production costs for anti-matter are projected for various energy source options and technology levels. Dedicated facilities using heavy ion collisions could produce antiproton at substantially less than 1 million $/milligram. With co-production of other valuable products, e.g., nuclear fuel for power reactors, antiproton costs could be reduced to even lower values

Large amounts of antiproton production by heavy ion collision

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Hiroshi; Powell, J.

1987-01-01

To produce large amounts of antiprotons, on the order of several grams/year, use of machines to produce nuclear collisions are studied. These can be of either proton-proton, proton-nucleus and nucleus-nucleus in nature. To achieve high luminosity colliding beams, on the order of 10/sup 41/ m/cm/sup 2/, a self-colliding machine is required, rather than a conventional circular colliding type. The self-colliding machine can produce additional antiprotons through successive collisions of secondary particles, such as spectator nucleons. A key problem is how to collect the produced antiprotons without capture by beam nuclei in the collision zone. Production costs for anti-matter are projected for various energy source options and technology levels. Dedicated facilities using heavy ion collisions could produce antiproton at substantially less than 1 million $/milligram. With co-production of other valuable products, e.g., nuclear fuel for power reactors, antiproton costs could be reduced to even lower values.

Effect of Wall Material on H– Production in a Plasma Sputter-Type Ion Source

Directory of Open Access Journals (Sweden)

Y. D. M. Ponce

2004-12-01

Full Text Available The effect of wall material on negative hydrogen ion (H– production was investigated in a multicusp plasma sputter-type ion source (PSTIS. Steady-state cesium-seeded hydrogen plasma was generated by a tungsten filament, while H– was produced through surface production using a molybdenum sputter target. Plasma parameters and H– yields were determined from Langmuir probe and Faraday cup measurements, respectively. At an input hydrogen pressure of 1.2 mTorr and optimum plasma discharge parameters Vd = –90 V and Id = –2.25 A, the plasma parameters ne was highest and T–e was lowest as determined from Langmuir probe measurements. At these conditions, aluminum generates the highest ion current density of 0.01697 mA/cm2, which is 64% more than the 0.01085 mA/cm2 that stainless steel produces. The yield of copper, meanwhile, falls between the two materials at 0.01164 mA/cm2. The beam is maximum at Vt = –125 V. Focusing is achieved at VL = –70 V for stainless steel, Vt = –60 V for aluminum, and Vt = –50 V for copper. The results demonstrate that proper selection of wall material can greatly enhance the H– production of the PSTIS.

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

International Nuclear Information System (INIS)

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

1986-01-01

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

Positive and negative ion mode comparison for the determination of DNA/peptide noncovalent binding sites through the formation of "three-body" noncovalent fragment ions.

Science.gov (United States)

Brahim, Bessem; Tabet, Jean-Claude; Alves, Sandra

2018-02-01

Gas-phase fragmentation of single strand DNA-peptide noncovalent complexes is investigated in positive and negative electrospray ionization modes.Collision-induced dissociation experiments, performed on the positively charged noncovalent complex precursor ions, have confirmed the trend previously observed in negative ion mode, i.e. a high stability of noncovalent complexes containing very basic peptidic residues (i.e. R > K) and acidic nucleotide units (i.e. Thy units), certainly incoming from the existence of salt bridge interactions. Independent of the ion polarity, stable noncovalent complex precursor ions were found to dissociate preferentially through covalent bond cleavages of the partners without disrupting noncovalent interactions. The resulting DNA fragment ions were found to be still noncovalently linked to the peptides. Additionally, the losses of an internal nucleic fragment producing "three-body" noncovalent fragment ions were also observed in both ion polarities, demonstrating the spectacular salt bridge interaction stability. The identical fragmentation patterns (regardless of the relative fragment ion abundances) observed in both polarities have shown a common location of salt bridge interaction certainly preserved from solution. Nonetheless, most abundant noncovalent fragment ions (and particularly three-body ones) are observed from positively charged noncovalent complexes. Therefore, we assume that, independent of the preexisting salt bridge interaction and zwitterion structures, multiple covalent bond cleavages from single-stranded DNA/peptide complexes rely on an excess of positive charges in both electrospray ionization ion polarities.

Development of a surface ionization source for the production of radioactive alkali ion beams in SPIRAL

International Nuclear Information System (INIS)

Eleon, C.; Jardin, P.; Gaubert, G.; Saint-Laurent, M.-G.; Alcantara-Nunez, J.; Alves Conde, R.; Barue, C.; Boilley, D.; Cornell, J.; Delahaye, P.; Dubois, M.; Jacquot, B.; Leherissier, P.; Leroy, R.; Lhersonneau, G.; Marie-Jeanne, M.; Maunoury, L.; Pacquet, J.Y.; Pellemoine, F.; Pierret, C.

2008-01-01

In the framework of the production of radioactive alkali ion beams by the isotope separation on-line (ISOL) method in SPIRAL I, a surface ionization source has been developed at GANIL to produce singly-charged ions of Li, Na and K. This new source has been designed to work in the hostile environment whilst having a long lifetime. This new system of production has two ohmic heating components: the first for the target oven and the second for the ionizer. The latter, being in carbon, offers high reliability and competitive ionization efficiency. This surface ionization source has been tested on-line using a 48 Ca primary beam at 60.3 A MeV with an intensity of 0.14 pA. The ionization efficiencies obtained for Li, Na and K are significantly better than the theoretical values of the ionization probability per contact. The enhanced efficiency, due to the polarization of the ionizer, is shown to be very important also for short-lived isotopes. In the future, this source will be associated with the multicharged electron-cyclotron-resonance (ECR) ion source NANOGAN III for production of multicharged alkali ions in SPIRAL. The preliminary tests of the set up are also presented in this contribution.

Pion production - a probe for coherence in medium energy heavy ion collisions

International Nuclear Information System (INIS)

Stachel, J.

1985-01-01

Neutral pion production is observed in heavy ion collisions at beam energies as low as 25 MeV/u, where this process is consumming the major portion of the total center of mass energy available. At these low beam energies single nucleon nucleon collision models and also models that incorporate the cooperative sharing of the beam energy of several nucleons do not reproduce the data. Rather, the data presented here call for a fully coherent production mechanism. (orig.)

LITERATURE SURVEY ON ISOTOPIC ABUNDANCE RATIO MEASUREMENTS - 2001-2005

International Nuclear Information System (INIS)

HOLDEN, N.E.

2005-01-01

Along with my usual weekly review of the published literature for new nuclear data, I also search for new candidates for best measurements of isotopic abundances from a single source. Most of the published articles, that I previously had found in the Research Library at the Brookhaven Lab, have already been sent to the members of the Atomic Weights Commission, by either Michael Berglund or Thomas Walczyk. In the last few days, I checked the published literature for any other articles in the areas of natural variations in isotopic abundance ratios, measurements of isotopic abundance ratios on samples of extra-terrestrial material and isotopic abundance ratio measurements performed using ICPMS instruments. Hopefully this information will be of interest to members of the Commission, the sub-committee on isotopic abundance measurements (SIAM), members of the former sub-committee on natural isotopic fractionation (SNIF), the sub-committee on extra-terrestrial isotope ratios (SETIR), the RTCE Task Group and the Guidelines Task Group, who are dealing with ICPMS and TIMS comparisons. In the following report, I categorize the publications in one of four areas. Measurements performed using either positive or negative ions with Thermal Ionization Mass Spectrometer, TIMS, instruments; measurements performed on Inductively Coupled Plasma Mass Spectrometer, ICPMS, instruments; measurements of natural variations of the isotopic abundance ratios; and finally measurements on extra-terrestrial samples with instrumentation of either type. There is overlap in these areas. I selected out variations and ET results first and then categorized the rest of the papers by TIMS and ICPMS

Carbon Abundances in Starburst Galaxies of the Local Universe

Energy Technology Data Exchange (ETDEWEB)

Peña-Guerrero, María A.; Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Mink, Selma de [Anton Pannekoek Institute for Astronomy, Science Park 904, P.O. Box 94249, 1090 GE, Amsterdam (Netherlands); Wofford, Aida [Instituto de Astronomía, UNAM, Ensenada, CP 22860, Baja California (Mexico); Kewley, Lisa, E-mail: pena@stsci.edu, E-mail: leitherer@stsci.edu, E-mail: S.E.deMink@uva.nl, E-mail: awofford@astrosen.unam.mx, E-mail: lisa.kewley@anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston ACT 2611 (Australia)

2017-10-01

The cosmological origin of carbon, the fourth most abundant element in the universe, is not well known and a matter of heavy debate. We investigate the behavior of C/O to O/H in order to constrain the production mechanism of carbon. We measured emission-line intensities in the spectral range from 1600 to 10000 Å on Space Telescope Imaging Spectrograph (STIS) long-slit spectra of 18 starburst galaxies in the local universe. We determined chemical abundances through traditional nebular analysis, and we used a Markov Chain Monte Carlo method to determine where our carbon and oxygen abundances lie in the parameter space. We conclude that our C and O abundance measurements are sensible. We analyzed the behavior of our sample in the [C/O] versus [O/H] diagram with respect to other objects such as DLAs, neutral ISM measurements, and disk and halo stars, finding that each type of object seems to be located in a specific region of the diagram. Our sample shows a steeper C/O versus O/H slope with respect to other samples, suggesting that massive stars contribute more to the production of C than N at higher metallicities, only for objects where massive stars are numerous; otherwise, intermediate-mass stars dominate the C and N production.

Carbon Abundances in Starburst Galaxies of the Local Universe

International Nuclear Information System (INIS)

Peña-Guerrero, María A.; Leitherer, Claus; Mink, Selma de; Wofford, Aida; Kewley, Lisa

2017-01-01

The cosmological origin of carbon, the fourth most abundant element in the universe, is not well known and a matter of heavy debate. We investigate the behavior of C/O to O/H in order to constrain the production mechanism of carbon. We measured emission-line intensities in the spectral range from 1600 to 10000 Å on Space Telescope Imaging Spectrograph (STIS) long-slit spectra of 18 starburst galaxies in the local universe. We determined chemical abundances through traditional nebular analysis, and we used a Markov Chain Monte Carlo method to determine where our carbon and oxygen abundances lie in the parameter space. We conclude that our C and O abundance measurements are sensible. We analyzed the behavior of our sample in the [C/O] versus [O/H] diagram with respect to other objects such as DLAs, neutral ISM measurements, and disk and halo stars, finding that each type of object seems to be located in a specific region of the diagram. Our sample shows a steeper C/O versus O/H slope with respect to other samples, suggesting that massive stars contribute more to the production of C than N at higher metallicities, only for objects where massive stars are numerous; otherwise, intermediate-mass stars dominate the C and N production.

Patterned ion exchange membranes for improved power production in microbial reverse-electrodialysis cells

KAUST Repository

Liu, Jia; Geise, Geoffrey M.; Luo, Xi; Hou, Huijie; Zhang, Fang; Feng, Yujie; Hickner, Michael A.; Logan, Bruce E.

2014-01-01

Power production in microbial reverse-electrodialysis cells (MRCs) can be limited by the internal resistance of the reverse electrodialysis stack. Typical MRC stacks use non-conductive spacers that block ion transport by the so-called spacer shadow

Production of highly charged ion beams Kr32+, Xe44+, Au54+ with Electron String Ion Source (ESIS) Krion-2 and corresponding basic and applied studies

Science.gov (United States)

Donets, D. E.; Donets, E. D.; Donets, E. E.; Salnikov, V. V.; Shutov, V. B.

2010-09-01

Electron String Ion Source (ESIS) Krion-2 (JINR, Dubna) was used for basic and applied research in various aspects of multiply charged heavy ions production. Energy recuperation mode in ESIS has been proofed first and used for production of highly charged ions 84Kr28+÷84Kr32+, 124Xe40÷124Xe44 and Au51+÷ Au54+. Krion-2 ESIS was mounted on high voltage (HV) platform of LU-20 Linac and used as an injector of highly charged ions during Nuclotron run N° 41. Krion-2 ESIS has produced 3.0.107 124Xe42+ ions per pulse of 7 μs duration. This ion beam was injected into LU-20 and Nuclotron, accelerated up to energy of 186 GeV and the extracted Xe beam was used for physics experiments. Electron String Ion Source Krion-2 demonstrated the high reliability and stability running during 30 days on HV platform. We believe that it is due to an extremely low electron beam power, provided by using the electron string mode of operation: 50 W pulse power and about 10 W average power. Other possible application of ESIS could be its use in injection complexes of synchrotrons and cyclotrons for cancer therapy. Slow and fast extraction of C4+ and C6+ beams from Krion-2 ESIS were preliminary studied towards ESIS optimization for medical accelerators requirements.

Increased reactive oxygen species production and lower abundance of complex I subunits and carnitine palmitoyltransferase 1B protein despite normal mitochondrial respiration in insulin-resistant human skeletal muscle

DEFF Research Database (Denmark)

Lefort, Natalie; Glancy, Brian; Bowen, Benjamin

2010-01-01

the higher ROS production. Tandem mass spectrometry identified protein abundance differences per mitochondrial mass in insulin resistance, including lower abundance of complex I subunits and enzymes involved in the oxidation of branched-chain amino acids (BCAA) and fatty acids (e.g., carnitine...

K vacancy production in collisions of 63 MeV Cu ions with Ge and Ag atoms

International Nuclear Information System (INIS)

Frank, W.; Jaracz, R.; Kaun, K.-H.; Rudiger, J.; Stachura, Z.

1980-01-01

The mechanism of K-shell vacancy production is studied in t in an X-ray-scattered ion coincidence experiment with 1 MeV/a.m.u. 63 Cu 4+ ion incident onto natural Ge and Ag targets. The impact parameter dependent K-shell vacancy production probability measured in the experiment is interpreted in terms of the rotational coupling and the statistical models. The dependence of the vacancy sharing process in the Cu-Ge collision system on the impact parameter is obtained and compared with the predictions of the Briggs-Myerhof-Demkov model

Abundance and distribution of antibiotic resistance genes in a full-scale anaerobic-aerobic system alternately treating ribostamycin, spiramycin and paromomycin production wastewater.

Science.gov (United States)

Tang, Mei; Dou, Xiaomin; Wang, Chunyan; Tian, Zhe; Yang, Min; Zhang, Yu

2017-12-01

The occurrence of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs) has been intensively investigated for wastewater treatment systems treating single class of antibiotic in recent years. However, the impacts of alternately occurring antibiotics in antibiotic production wastewater on the behavior of ARGs in biological treatment systems were not well understood yet. Herein, techniques including high-capacity quantitative PCR and quantitative PCR (qPCR) were used to investigate the behavior of ARGs in an anaerobic-aerobic full-scale system. The system alternately treated three kinds of antibiotic production wastewater including ribostamycin, spiramycin and paromomycin, which referred to stages 1, 2 and 3. The aminoglycoside ARGs (52.1-79.3%) determined using high-capacity quantitative PCR were the most abundant species in all sludge samples of the three stages. The total relative abundances of macrolide-lincosamide-streptogramin (MLS) resistance genes and aminoglycoside resistance genes measured using qPCR were significantly higher (P  0.05) in both aerobic and anaerobic sludge samples. In aerobic sludge, one acetyltransferase gene (aacA4) and the other three nucleotidyltransferase genes (aadB, aadA and aadE) exhibited positive correlations with intI1 (r 2  = 0.83-0.94; P < 0.05), implying the significance of horizontal transfer in their proliferation. These results and facts will be helpful to understand the abundance and distribution of ARGs from antibiotic production wastewater treatment systems.

Hydrocarbons and fuels analyses with the supersonic gas chromatography mass spectrometry--the novel concept of isomer abundance analysis.

Science.gov (United States)

Fialkov, Alexander B; Gordin, Alexander; Amirav, Aviv

2008-06-27

Hydrocarbon analysis with standard GC-MS is confronted by the limited range of volatile compounds amenable for analysis and by the similarity of electron ionization mass spectra for many compounds which show weak or no molecular ions for heavy hydrocarbons. The use of GC-MS with supersonic molecular beams (Supersonic GC-MS) significantly extends the range of heavy hydrocarbons that can be analyzed, and provides trustworthy enhanced molecular ion to all hydrocarbons. In addition, unique isomer mass spectral features are obtained in the ionization of vibrationally cold hydrocarbons. The availability of molecular ions for all hydrocarbons results in the ability to obtain unique chromatographic isomer distribution patterns that can serve as a new method for fuel characterization and identification. Examples of the applicability and use of this novel isomer abundance analysis (IAA) method to diesel fuel, kerosene and oil analyses are shown. It is suggested that in similarity to the "three ions method" for identification purposes, three isomer abundance patterns can serve for fuel characterization. The applications of the Supersonic GC-MS for engine motor oil analysis and transformer oil analysis are also demonstrated and discussed, including the capability to achieve fast 1-2s sampling without separation for oil and fuel fingerprinting. The relatively fast analysis of biodiesel is described, demonstrating the provision of molecular ions to heavy triglycerides. Isomer abundance analysis with the Supersonic GC-MS could find broad range of applications including petrochemicals and fuel analysis, arson analysis, environmental oil/fuel spill analysis, fuel adulteration analysis and motor oil analysis.

Production and sympathetic cooling of complex molecular ions

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chaobo

2008-06-24

This thesis reports on experimental and theoretical studies of the sympathetic cooling of complex molecular ions demonstrating that this general method for cooling atomic and molecular ions is reliable and efficient. For this purpose, complex molecular ions and barium ions have been confined simultaneously in a linear Paul trap. The complex molecular ions are generated in an electrospray ionization system and transferred to the trap via a 2 m long octopole ion guide. These molecular ions are pre-cooled by room temperature helium buffer gas so that they can be captured by the trap. The atomic barium ions are loaded from a barium evaporator oven and are laser-cooled by a 493 nm cooling laser and a 650 nm repumping laser. Due to the mutual Coulomb interaction among these charged particles, the kinetic energy of the complex molecular ions can be reduced significantly. In our experiments we have demonstrated the sympathetic cooling of various molecules (CO{sub 2}, Alexa Fluor 350, glycyrrhetinic acid, cytochrome c) covering a wide mass range from a few tens to 13000 amu. In every case the molecular ions could be cooled down to millikelvin temperatures. Photo-chemical reactions of the {sup 138}Ba{sup +} ions in the ({sup 2}P{sub 1/2}) excited state with gases such as O{sub 2}, CO{sub 2}, or N{sub 2}O, could be observed. If the initial {sup 138}Ba{sup +} ion ensemble is cold, the produced {sup 138}BaO{sup +} ions are cold as well, with a similar temperature as the laser-cooled barium ions (a few tens of millikelvin). The back-reaction of {sup 138}BaO{sup +} ions with neutral CO to {sup 138}Ba{sup +} is possible and was observed in our experiments as well. A powerful molecular dynamics (MD) simulation program has been developed. With this program dynamic properties of ion ensembles, such as sympathetic interactions or heating effects, have been investigated and experimental results have been analyzed to obtain, for example, ion numbers and temperatures. Additionally, the

Production and sympathetic cooling of complex molecular ions

International Nuclear Information System (INIS)

Zhang, Chaobo

2008-01-01

This thesis reports on experimental and theoretical studies of the sympathetic cooling of complex molecular ions demonstrating that this general method for cooling atomic and molecular ions is reliable and efficient. For this purpose, complex molecular ions and barium ions have been confined simultaneously in a linear Paul trap. The complex molecular ions are generated in an electrospray ionization system and transferred to the trap via a 2 m long octopole ion guide. These molecular ions are pre-cooled by room temperature helium buffer gas so that they can be captured by the trap. The atomic barium ions are loaded from a barium evaporator oven and are laser-cooled by a 493 nm cooling laser and a 650 nm repumping laser. Due to the mutual Coulomb interaction among these charged particles, the kinetic energy of the complex molecular ions can be reduced significantly. In our experiments we have demonstrated the sympathetic cooling of various molecules (CO 2 , Alexa Fluor 350, glycyrrhetinic acid, cytochrome c) covering a wide mass range from a few tens to 13000 amu. In every case the molecular ions could be cooled down to millikelvin temperatures. Photo-chemical reactions of the 138 Ba + ions in the ( 2 P 1/2 ) excited state with gases such as O 2 , CO 2 , or N 2 O, could be observed. If the initial 138 Ba + ion ensemble is cold, the produced 138 BaO + ions are cold as well, with a similar temperature as the laser-cooled barium ions (a few tens of millikelvin). The back-reaction of 138 BaO + ions with neutral CO to 138 Ba + is possible and was observed in our experiments as well. A powerful molecular dynamics (MD) simulation program has been developed. With this program dynamic properties of ion ensembles, such as sympathetic interactions or heating effects, have been investigated and experimental results have been analyzed to obtain, for example, ion numbers and temperatures. Additionally, the feasibility of nondestructive spectroscopy via an optical dipole excitation

A novel magnetic ion imprinted polymer as a selective magnetic solid phase for separation of trace lead(II) ions from agricultural products, and optimization using a Box-Behnken design.

Science.gov (United States)

Dahaghin, Zohreh; Mousavi, Hassan Zavvar; Sajjadi, S Maryam

2017-12-15

In this work, a magnetic ion-imprinted polymer (Fe 3 O 4 @SiO 2 @IIP) as a novel and selective nanosorbent for selective extraction of Pb(II) ions from various agricultural products is presented. The novel lead magnetic ion-imprinted polymer was synthesized by imidazole as a new ligand and grafted onto the surface of Fe 3 O 4 @SiO 2 NPs. A Box-Behnken (BBD) design was used for optimization of the extraction and elution steps. In the selected conditions, the limit of detection was 0.48ngmL -1 , preconcentration factor was 300, the sorption capacity of this new magnetic ion-imprinted polymer was 105mgg -1 , and the precision of the method (RSD%) for six replicate measurements was found 3.2%. Finally, the feasibility of the new magnetic ion-imprinted polymer was evaluated by extraction and determination of trace Pb 2+ ions in different agricultural products including (orange, mango, apple, kiwi, lettuce, broccoli, carrot, squash, eggplant, radish, mushroom, cucumber, and tomato). Copyright © 2017 Elsevier Ltd. All rights reserved.

Universal behavior of charged particle production in heavy ion collisions at RHIC energies

Science.gov (United States)

Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Phobos Collaboration

2003-04-01

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at √ SNN = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/ overlinepp and e +e - data. / in nuclear collisions at high energy scales with √ s in a similar way as Nch in e +e - collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

Detection of abundant ethane and methane, along with carbon monoxide and water, in comet C/1996 B2 Hyakutake: evidence for interstellar origin

Science.gov (United States)

Mumma, M. J.; DiSanti, M. A.; Dello Russo, N.; Fomenkova, M.; Magee-Sauer, K.; Kaminski, C. D.; Xie, D. X.

1996-01-01

The saturated hydrocarbons ethane (C2H6) and methane (CH4) along with carbon monoxide (CO) and water (H2O) were detected in comet C/1996 B2 Hyakutake with the use of high-resolution infrared spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. The inferred production rates of molecular gases from the icy, cometary nucleus (in molecules per second) are 6.4 X 10(26) for C2H6, 1.2 X 10(27) for CH4, 9.8 X 10(27) for CO, and 1.7 X 10(29) for H2O. An abundance of C2H6 comparable to that of CH4 implies that ices in C/1996 B2 Hyakutake did not originate in a thermochemically equilibrated region of the solar nebula. The abundances are consistent with a kinetically controlled production process, but production of C2H6 by gas-phase ion molecule reactions in the natal cloud core is energetically forbidden. The high C2H6/CH4 ratio is consistent with production of C2H6 in icy grain mantles in the natal cloud, either by photolysis of CH4-rich ice or by hydrogen-addition reactions to acetylene condensed from the gas phase.

FOBOS - a 4π-fragment spectrometer for heavy-ion reaction products

International Nuclear Information System (INIS)

Ortlepp, H.G.; Schilling, K.D.

1992-06-01

The FOBOS detector presently under construction at Dubna is intended for heavy ion reaction studies in the bombarding energy range of 10...100 AMeV. It will consist of a 'gas-ball' of 30 position-sensitive avalanche counters and 30 axial ionization chambers behind them, a shell of 190 scintillation counters surrounding the gas ball and a forward phoswich array. All charged reaction products may be measured in a wide dynamic range and in a geometry covering a substantial part of 4π. Special developments were necessary concerning the mechanical construction, the detector design, the evacuation and gas supply and the electronics. Presently individual detector modules are being tested at the beam of the U-400 heavy ion cyclotron of the Laboratory of nuclear reactions. (orig.)

Excited-atom production by electron and ion bombardment of alkali halides

International Nuclear Information System (INIS)

Walkup, R.E.; Avouris, P.; Ghosh, A.P.

1987-01-01

We present experimental results on the production of excited atoms by electron and ion bombardment of alkali halides. For the case of electron bombardment, Doppler shift measurements show that the electronically excited atoms have a thermal velocity distribution in equilibrium with the surface temperature. Measurements of the absolute yield of excited atoms, the distribution of population among the excited states, and the systematic dependence on incident electron current and sample temperature support a model in which the excited atoms are produced by gas-phase collisions between desorbed ground-state atoms and secondary electrons. In contrast, for the case of ion bombardment, the excited atoms are directly sputtered from the surface, with velocity distributions characteristic of a collision cascade, and with typical energies of --10 eV

Dust formation in a galaxy with primitive abundances.

Science.gov (United States)

Sloan, G C; Matsuura, M; Zijlstra, A A; Lagadec, E; Groenewegen, M A T; Wood, P R; Szyszka, C; Bernard-Salas, J; van Loon, J Th

2009-01-16

Interstellar dust plays a crucial role in the evolution of galaxies. It governs the chemistry and physics of the interstellar medium. In the local universe, dust forms primarily in the ejecta from stars, but its composition and origin in galaxies at very early times remain controversial. We report observational evidence of dust forming around a carbon star in a nearby galaxy with a low abundance of heavy elements, 25 times lower than the solar abundance. The production of dust by a carbon star in a galaxy with such primitive abundances raises the possibility that carbon stars contributed carbonaceous dust in the early universe.

Processes of hypernuclei formation in relativistic ion collisions

Directory of Open Access Journals (Sweden)

Botvina Alexander

2018-01-01

Full Text Available The study of hypernuclei in relativistic ion collisions open new opportunities for nuclear and particle physics. The main processes leading to the production of hypernuclei in these reactions are the disintegration of large excited hyper-residues (target- and projectile-like, and the coalescence of hyperons with other baryons into light clusters. We use the transport, coalescence and statistical models to describe the whole reaction, and demonstrate the effectiveness of this approach: These reactions lead to the abundant production of multi-strange nuclei and new hypernuclear states. A broad distribution of predicted hypernuclei in masses and isospin allows for investigating properties of exotic hypernuclei, as well as the hypermatter both at high and low temperatures. There is a saturation of the hypernuclei production at high energies, therefore, the optimal way to pursue this experimental research is to use the accelerator facilities of intermediate energies, like FAIR (Darmstadt and NICA (Dubna.

Use of an ions thruster to dispose of type II long-lived fission products into outer space

International Nuclear Information System (INIS)

Takahashi, H.; Yu, A.

1997-01-01

To dispose of long-lived fission products (LLFPs) into outer space, an ions thruster can be used instead of a static accelerator. The specifications of the ions thrusters which are presently studies for space propulsion are presented, and their usability discussed. Using of a rocket with an ions thruster for disposing of the LLFPs directly into the sun required a larger amount of energy than does the use of an accelerator

ICP-oa TOFMS utilisation to determine the Gd isotopic abundance in gadolinium nitrate

International Nuclear Information System (INIS)

Dragomir, M.; Ohai, D.; Dumitrescu, I.; Furtuna, I.

2010-01-01

This paper is describes the development of a method that should permit the determination of isotope abundance of gadolinium in gadolinium nitrate, used as burnable poison at Cernavoda NPP. To determine the isotopic abundance of gadolinium the inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer (ICP-oa TOFMS) was used. The ICP-oa TOFMS allows the elimination of noise associated with instrumental drift and instability (flicker noise). The absence of flicker noise in the ICP-oa TOFMS means that the isotope ratios can be measured up to the statistical limit of ion counting. With TOFMS, each spectrum acquired represents signals from ions extracted from the plasma during the same time interval, formed from identical plasma and sample introduction events. Therefore, the ICP-oa TOFMS, Optimass 8000, has been successfully used for isotope ratio measurements of Gd in gadolinium nitrate [Gd (NO 3 ) 3 x 6H 2 O] sample solutions. (authors)

Abundance analysis from the UV spectrum of the He-w star HR 6000

International Nuclear Information System (INIS)

Castelli, F.; Cornachin, M.; Morossi, C.; Hack, M.

1984-01-01

A high resolution spectrum of the He-w star HR 6000, covering the SW and LW regions, has been analysed. A fully line-blanketed model atmosphere with parameters Tsub(e) = 14000 K, log g = 4, microturbulence xi = 2 km.s -1 has been adopted. This model is in agreement with the photometric data and yields the same abundance for the Fe II and Fe III ions. By using the synthetic spectrum method we compared the observed lines with the computed ones. We find an underabundance of C, Al Si, Mg, S, Sc, Co, Ni, Zn and an overabundance of Be, P, Cl, Ti, Mn, Fe, Ga. B, O, Cr have nearly solar abundances. Circumstellar (or interstellar) shortward-shifted components affect the strong resonance lines of the following ions: C II(1) lambda 1334.535, O I(2) lambda 1302.074,Mg II(1) lambda 2795.523, lambda 2802.698, Si II(3) lambda 1304.369, Fe II(1) lambda 2599.395

Enhanced wear resistance of production tools and steel samples by implantation of nitrogen and carbon ions

International Nuclear Information System (INIS)

Mikkelsen, N.J.; Straede, C.A.

1992-01-01

In recent years ion implantation has become a feasible technique for obtaining improved wear resistance of production tools. However, basic knowledge of how and in which cases ion implantation is working at its best is still needed. The present paper discusses structural and tribological investigations of carbon and nitrogen implanted steels. The nitrogen data were obtained mainly from field tests and the investigation of carbon implantations took place mainly in the laboratory. A study was made of how the tribological behaviour of implanted steels changes with different implantation parameters. The tribological laboratory investigations were carried out using pin-on-disc equipment under controlled test conditions, and deal with high dose carbon implantation (approximately (1-2)x10 18 ions cm -2 ). The wear resistance of steels was enhanced dramatically, by up to several orders of magnitude. The field test results cover a broad range of ion implanted production tools, which showed a marked improvement in wear resistance. Nitrogen implanted tools are also compared with carbon and titanium implanted tools. (orig.)

Analysis of products of thymine irradiated by 18O8+ ion beam in N2O saturated aqueous solution

International Nuclear Information System (INIS)

Cai Xichen; Wei Zengquan; Li Wenjian; Liang Jianping; Li Qiang

1999-01-01

Some methods of capillary gas chromatography, such as GC, GC-MS GC-FT-IR, are used to analyze the products of thymine irradiated by 18 O 8+ ion beam in N 2 O saturated aqueous solution. From the results of GC-MS the molecular weight of products can be determined, and from the results of GC-FT-IR some molecular structure information of products can be obtained. By this way the products, 5,6-Dihydro-thymine, 5-Hydroxyl-5-Methylhydantoin, 5-Hydroxyl-6-Hydro-thymine, 5-Hydro-6-Hydroxyl thymine, 5-Hydroxymethyluracil, Trans-Thymine glycol, Cis-Thymine glycol and dimers are determined without separation of them from samples. Though these products are as same as those products of thymine irradiated by γ rays in N 2 O saturated aqueous solution, the mechanism of thymine irradiated by heavy ion beam in aqueous solution is different from that by γ rays. The main products of thymine irradiated by 18 O 8+ ion beam in N 2 O saturated aqueous solution are hydroxyl adducts at 5-6 band of thymine, while the main products of thymine irradiated by γ ray in N 2 O saturated aqueous solution are dimers of thymine

Heavy flavour production at CMS in heavy ion collisions

CERN Document Server

Nguyen, Matthew

2015-01-01

We review recent results relating to beauty production in heavy-ion collisions, in both the closed and open heavy flavor sectors, from the CMS experiment at the LHC. The sequential suppression of the ° states in PbPb collisions is thought to be evidence of the dissociation of quarkonia bound states in deconfined matter. Data from pPb collisions demonstrate that while cold nuclear effects appear to be subdominant in minimum bias collisions, there exists a non-trivial dependence on collision multiplicity that remains to be understood. The suppression of high p T particles in heavy-ion collisions, relative to the expectation from pp collisions, is typically interpreted in terms of energy loss of hard scattered parton in the dense nuclear medium. The flavor dependence of the energy loss may be accessed via measurements of b hadrons and b-tagged jets. Measurement of B mesons, via non-prompt J = y , at relatively low p T indicate a smaller suppression factor than D meson or inclusive charged hadrons. Data on b jet...

SnSe2 Two Dimensional Anodes for Advanced Sodium Ion Batteries

KAUST Repository

Zhang, Fan

2017-01-01

Sodium-ion batteries (SIBs) are considered as a promising alternative to lithium-ion batteries (LIBs) for large-scale renewable energy storage units due to the abundance of sodium resource and its low cost. However, the development of anode

Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments

DEFF Research Database (Denmark)

Schneider, M.; Johnson, T.; Dumont, R.

2016-01-01

Recent JET experiments have been dedicated to the studies of fusion reactions between deuterium (D) and Helium-3 (3He) ions using neutral beam injection (NBI) in synergy with third harmonic ion cyclotron radio-frequency heating (ICRH) of the beam. This scenario generates a fast ion deuterium tail...... enhancing DD and D3He fusion reactions. Modelling and measuring the fast deuterium tail accurately is essential for quantifying the fusion products. This paper presents the modelling of the D distribution function resulting from the NBI+ICRF heating scheme, reinforced by a comparison with dedicated JET fast...

Low-cost carbon-silicon nanocomposite anodes for lithium ion batteries.

Science.gov (United States)

Badi, Nacer; Erra, Abhinay Reddy; Hernandez, Francisco C Robles; Okonkwo, Anderson O; Hobosyan, Mkhitar; Martirosyan, Karen S

2014-01-01

The specific energy of the existing lithium ion battery cells is limited because intercalation electrodes made of activated carbon (AC) materials have limited lithium ion storage capacities. Carbon nanotubes, graphene, and carbon nanofibers are the most sought alternatives to replace AC materials but their synthesis cost makes them highly prohibitive. Silicon has recently emerged as a strong candidate to replace existing graphite anodes due to its inherently large specific capacity and low working potential. However, pure silicon electrodes have shown poor mechanical integrity due to the dramatic expansion of the material during battery operation. This results in high irreversible capacity and short cycle life. We report on the synthesis and use of carbon and hybrid carbon-silicon nanostructures made by a simplified thermo-mechanical milling process to produce low-cost high-energy lithium ion battery anodes. Our work is based on an abundant, cost-effective, and easy-to-launch source of carbon soot having amorphous nature in combination with scrap silicon with crystalline nature. The carbon soot is transformed in situ into graphene and graphitic carbon during mechanical milling leading to superior elastic properties. Micro-Raman mapping shows a well-dispersed microstructure for both carbon and silicon. The fabricated composites are used for battery anodes, and the results are compared with commercial anodes from MTI Corporation. The anodes are integrated in batteries and tested; the results are compared to those seen in commercial batteries. For quick laboratory assessment, all electrochemical cells were fabricated under available environment conditions and they were tested at room temperature. Initial electrochemical analysis results on specific capacity, efficiency, and cyclability in comparison to currently available AC counterpart are promising to advance cost-effective commercial lithium ion battery technology. The electrochemical performance observed for

Effects of sawtooth crashes on beam ions and fusion product tritons in JET

Energy Technology Data Exchange (ETDEWEB)

Marcus, F.B.; Hone, M.A.; Jarvis, O.N.; Loughlin, M.J.; Sadler, G. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Adams, J.M.; Bond, D.S.; Watkins, N. [AEA Technology, Harwell (United Kingdom); Howarth, P.J.A. [Birmingham Univ. (United Kingdom)

1994-12-31

The objective of this study is to examine the effect of a sawtooth crash on the radial distribution of the slowing down fusion product tritons and on beam ions. The JET neutron emission profile monitor was used to measure the 2.5 MeV and 14 MeV neutron emission line-integrals before and after sawtooth crashes in the Joint European Torus (JET). In deuterium discharges, the 14 MeV neutron production was wholly attributable to burnup of the 1 MeV fusion product tritons from d-d fusion. It has been known for many years that the global emission of 14 MeV neutrons is not affected by sawtooth crashes. Examination of the data obtained with the profile monitor shows that the local emissivity of 14 MeV neutrons, and hence of the profile of thermalizing tritons, is only weakly affected by crashes in the discharges studied. This is in contradiction with the apparent behaviour of injected beam ions as deduced from a study of the considerable changes in local emissivity of the 2.5 MeV neutrons. Nevertheless, the behaviour of the fusion product tritons is consistent with the scaling of the beam injected deuterium. (author) 1 ref., 6 figs.

Composition of heavy ions in solar energetic particle events

International Nuclear Information System (INIS)

Fan, C.Y.; Gloeckler, G.

1983-01-01

The elemental, charge state, and isotopic composition of approximately 1 to 20 MeV per nucleon ions in solar energetic particle (SEP) events was determined and current understanding of the nature of solar and interplanetary processes which may explain the observations are outlined. The composition within individual SEP events may vary both with time and energy, and will in general be different from that in other SEP events. Average values of relative abundances measured in a large number of SEP events, however are found to be roughly energy independent in the approximately 1 to approximately 20 MeV per nucleon range, and show a systematic deviation from photospheric abundances which seem to be organized in terms of the first ionization potential of the ion. Direct measurements of the charge states of SEPs have revealed the surprisingly common presence of energetic He(+) along with heavy ions with typical coronal ionization states. High resolution measurements of isotopic abundance ratios in a small number of SEP events show these to be consistent with the universal composition except for the puzzling overabundance of the SEP Ne-22 relative to this isotopes ratio in the solar wind

Dynamic molecular oxygen production in cometary comae

Science.gov (United States)

Yao, Yunxi; Giapis, Konstantinos P.

2017-05-01

Abundant molecular oxygen was discovered in the coma of comet 67P/Churyumov-Gerasimenko. Its origin was ascribed to primordial gaseous O2 incorporated into the nucleus during the comet's formation. This thesis was put forward after discounting several O2 production mechanisms in comets, including photolysis and radiolysis of water, solar wind-surface interactions and gas-phase collisions. Here we report an original Eley-Rideal reaction mechanism, which permits direct O2 formation in single collisions of energetic water ions with oxidized cometary surface analogues. The reaction proceeds by H2O+ abstracting a surface O-atom, then forming an excited precursor state, which dissociates to produce O2-. Subsequent photo-detachment leads to molecular O2, whose presence in the coma may thus be linked directly to water molecules and their interaction with the solar wind. This abiotic O2 production mechanism is consistent with reported trends in the 67P coma and raises awareness of the role of energetic negative ions in comets.

Ion-Exchange Sample Displacement Chromatography as a Method for Fast and Simple Isolation of Low- and High-Abundance Proteins from Complex Biological Mixtures

Directory of Open Access Journals (Sweden)

Martina Srajer Gajdosik

2014-01-01

Full Text Available Sample displacement chromatography (SDC in reversed phase and ion-exchange modes was introduced at the end of 1980s. This chromatographic method was first used for preparative purification of synthetic peptides, and subsequently adapted for protein fractionation, mainly in anion-exchange mode. In the past few years, SDC has been successfully used for enrichment of low- and medium-abundance proteins from complex biological fluids on both monolithic and bulk chromatographic supports. If aqueous mobile phase is used with the application of mild chromatographic conditions, isolated proteins are not denatured and can also keep their biological activity. In this paper, the use of SDC in anion-exchange mode on a high-capacity chromatographic resin for separation of proteins from complex biological mixtures such as human plasma is demonstrated. By use of three and more columns coupled in series during sample application, and subsequent parallel elution of detached columns, additional separation of bound proteins was achieved. Highly enriched human serum albumin fraction and a number of physiologically active medium- and low-abundance proteins could be fractionated and detected by electrospray ionization tandem mass spectrometry (ESI-MS/MS and matrix assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS. The use of the aforementioned columns that can be sanitized with 1 M sodium hydroxide for further application of SDC in biotechnology and food technology was discussed.

Theoretical contributions to coherent pion production in subthreshold and relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Deutchman, P.A.; Norbury, J.W.; Townsend, L.W.

1986-01-01

The analysis results from a microscopic calculation for pion production in heavy-ion collisions at intermediate to relativistic energies both above and below pion threshold are presented and the most important terms that contribute to the pion spectrum are determined. The energy dependence and the effects on the pion spectrum due to the various parameters in the theory are examined. The model is applied to coherent pion-production in 16 O + 12 C collisions. (orig.)

Hypernuclei, dibaryon and antinuclei production in high energy heavy ion collisions: Thermal production vs. coalescence

International Nuclear Information System (INIS)

Steinheimer, J.; Gudima, K.; Botvina, A.; Mishustin, I.; Bleicher, M.; Stöcker, H.

2012-01-01

We study the production of (hyper-)nuclei and dibaryons in most central heavy ion collisions at energies of E lab =1-160 A GeV. In particular we are interested in clusters produced from the hot and dense fireball. The formation rate of strange and non-strange clusters is estimated by assuming thermal production from the intermediate phase of the UrQMD-hydro hybrid model and alternatively by the coalescence mechanism from a hadronic cascade model. Both model types are compared in detail. For most energies we find that both approaches agree in their predictions for the yields of the clusters. Only for very low beam energies, and for dibaryons including Ξ's, we observe considerable differences. We also study the production of anti-matter clusters up to top RHIC energies and show that the observation of anti- 4 He and even anti- 4 Λ He is feasible. We have found a considerable qualitative difference in the energy dependence of the strangeness population factor R H when comparing the thermal production with the coalescence results.

Silicene for Na-ion battery applications

KAUST Repository

Zhu, Jiajie

2016-08-19

Na-ion batteries are promising candidates to replace Li-ion batteries in large scale applications because of the advantages in natural abundance and cost of Na. Silicene has potential as the anode in Li-ion batteries but so far has not received attention with respect to Na-ion batteries. In this context, freestanding silicene, a graphene-silicene-graphene heterostructure, and a graphene-silicene superlattice are investigated for possible application in Na-ion batteries, using first-principles calculations. The calculated Na capacities of 954mAh/g for freestanding silicene and 730mAh/g for the graphenesilicene superlattice (10% biaxial tensile strain) are highly competitive and potentials of >0.3 V against the Na/Na potential exceed the corresponding value of graphite. In addition, the diffusion barriers are predicted to be <0.3 eV.

Clustering in the stellar abundance space

Science.gov (United States)

Boesso, R.; Rocha-Pinto, H. J.

2018-03-01

We have studied the chemical enrichment history of the interstellar medium through an analysis of the n-dimensional stellar abundance space. This work is a non-parametric analysis of the stellar chemical abundance space. The main goal is to study the stars from their organization within this abundance space. Within this space, we seek to find clusters (in a statistical sense), that is, stars likely to share similar chemo-evolutionary history, using two methods: the hierarchical clustering and the principal component analysis. We analysed some selected abundance surveys available in the literature. For each sample, we labelled the group of stars according to its average abundance curve. In all samples, we identify the existence of a main enrichment pattern of the stars, which we call chemical enrichment flow. This flow is set by the structured and well-defined mean rate at which the abundances of the interstellar medium increase, resulting from the mixture of the material ejected from the stars and stellar mass-loss and interstellar medium gas. One of the main results of our analysis is the identification of subgroups of stars with peculiar chemistry. These stars are situated in regions outside of the enrichment flow in the abundance space. These peculiar stars show a mismatch in the enrichment rate of a few elements, such as Mg, Si, Sc and V, when compared to the mean enrichment rate of the other elements of the same stars. We believe that the existence of these groups of stars with peculiar chemistry may be related to the accretion of planetary material on to stellar surfaces or may be due to production of the same chemical element by different nucleosynthetic sites.

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.)

All-solid-state lithium-ion and lithium metal batteries - paving the way to large-scale production

Science.gov (United States)

Schnell, Joscha; Günther, Till; Knoche, Thomas; Vieider, Christoph; Köhler, Larissa; Just, Alexander; Keller, Marlou; Passerini, Stefano; Reinhart, Gunther

2018-04-01

Challenges and requirements for the large-scale production of all-solid-state lithium-ion and lithium metal batteries are herein evaluated via workshops with experts from renowned research institutes, material suppliers, and automotive manufacturers. Aiming to bridge the gap between materials research and industrial mass production, possible solutions for the production chains of sulfide and oxide based all-solid-state batteries from electrode fabrication to cell assembly and quality control are presented. Based on these findings, a detailed comparison of the production processes for a sulfide based all-solid-state battery with conventional lithium-ion cell production is given, showing that processes for composite electrode fabrication can be adapted with some effort, while the fabrication of the solid electrolyte separator layer and the integration of a lithium metal anode will require completely new processes. This work identifies the major steps towards mass production of all-solid-state batteries, giving insight into promising manufacturing technologies and helping stakeholders, such as machine engineering, cell producers, and original equipment manufacturers, to plan the next steps towards safer batteries with increased storage capacity.

Dissociation mechanism of HNIW ions investigated by chemical ionization and electron impact mass spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Yang, Rongjie; Xiao, Hemiao [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2006-04-15

Chemical Ionization (CI) with Collision-Induced Dissociation (CID) spectroscopy and Electron Impacting (EI) with metastable Mass analyzed Ion Kinetic Energy (MIKE) spectroscopy have been applied to study ionic dissociations of Hexanitrohexaazaisowurtzitane (HNIW). Similarities and differences between EI/MIKE and CI/CID mass spectra of HNIW were analyzed. In EI mass spectra, the ions [HNIW-n NO{sub 2}]{sup +} (n=2-5), such as the ion at m/z 347, were less frequent (1-2% relative abundance), but in CI mass spectra, these ions were very abundant. For some ions of large molar mass from HNIW, their dissociations pathways from parent ions to daughter ions were built according to CID and MIKE spectra. Molecular ions of HNIW with a protonated nitro group at five-member ring seem more stable than at six-member ring. The HNIW ions losing five of six nitro groups are very stable based on CID spectra, which agrees with some research results for thermal decomposition of HNIW in literature. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Volatile products controlling Titan's tholins production

KAUST Repository

Carrasco, Nathalie

2012-05-01

A quantitative agreement between nitrile relative abundances and Titan\\'s atmospheric composition was recently shown with a reactor simulating the global chemistry occurring in Titan\\'s atmosphere (Gautier et al. [2011]. Icarus, 213, 625-635). Here we present a complementary study on the same reactor using an in situ diagnostic of the gas phase composition. Various initial N 2/CH 4 gas mixtures (methane varying from 1% to 10%) are studied, with a monitoring of the methane consumption and of the stable gas neutrals by in situ mass spectrometry. Atomic hydrogen is also measured by optical emission spectroscopy. A positive correlation is found between atomic hydrogen abundance and the inhibition function for aerosol production. This confirms the suspected role of hydrogen as an inhibitor of heterogeneous organic growth processes, as found in Sciamma-O\\'Brien et al. (Sciamma-O\\'Brien et al. [2010]. Icarus, 209, 704-714). The study of the gas phase organic products is focussed on its evolution with the initial methane amount [CH 4] 0 and its comparison with the aerosol production efficiency. We identify a change in the stationary gas phase composition for intermediate methane amounts: below [CH 4] 0=5%, the gas phase composition is mainly dominated by nitrogen-containing species, whereas hydrocarbons are massively produced for [CH 4] 0>5%. This predominance of N-containing species at lower initial methane amount, compared with the maximum gas-to solid conversion observed in Sciamma-O\\'Brien et al. (2010) for identical methane amounts confirms the central role played by N-containing gas-phase compounds to produce tholins. Moreover, two protonated imines (methanimine CH 2NH and ethanamine CH 3CHNH) are detected in the ion composition in agreement with Titan\\'s INMS measurements, and reinforcing the suspected role of these chemical species on aerosol production. © 2012 Elsevier Inc.

Production of hypernuclei in peripheral collisions of relativistic ions

Energy Technology Data Exchange (ETDEWEB)

Botvina, A.S., E-mail: a.botvina@gsi.de [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow (Russian Federation); Gudima, K.K. [Institute of Applied Physics, Academy of Sciences of Moldova, MD-2028 Kishinev (Moldova, Republic of); Steinheimer, J. [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Mishustin, I.N. [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Kurchatov Institute, Russian Research Center, 123182 Moscow (Russian Federation); Pochodzalla, J.; Sanchez Lorente, A. [The Helmholtz Institute Mainz (HIM), Johann-Joachim-Becher-Weg 36, 55099 Mainz (Germany); Bleicher, M. [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Stoecker, H. [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, 62491 Darmstadt (Germany)

2012-05-01

Formation of hypernuclei in peripheral collisions of relativistic light and heavy ions is studied theoretically within the transport and statistical approaches. New mechanisms for the formation of strange nuclear systems via capture of hyperons by slightly excited spectator matter and their subsequent disintegration are investigated. These processes lead to production of specific and exotic hypernuclei, which may not be accessible in other reactions. Similar mechanisms processing via absorption of strange particles by nuclei can take place in reactions initiated by electrons, antiprotons and other hadrons. It is demonstrated that our approach is consistent with experimental data.

Dilepton and vector meson production in heavy-ion reactions

International Nuclear Information System (INIS)

Wolf, Gy.

1997-01-01

A nonperturbative dynamical study of dilepton an vector meson production in heavy-ion collisions from 1 to 2 GeV/A bombarding energies is presented incorporating all known sources relevant in this energy range. The dynamical evolution of the nucleus-nucleus collision is described by a transport equation of the Boltzmann-Uehling-Uhlenbeck type evolving phase-space distribution functions for nucleons, baryon resonances, pions, η's, ρ's and σ's with their isospin degrees of freedom. In particular, the sensitivity of the calculated yields to predicted changes of the ρ and ω mesons in dense matter is investigated. (author)

Production of hypernuclei in peripheral collisions of relativistic ions

International Nuclear Information System (INIS)

Botvina, A.S.; Gudima, K.K.; Steinheimer, J.; Mishustin, I.N.; Pochodzalla, J.; Sanchez Lorente, A.; Bleicher, M.; Stoecker, H.

2012-01-01

Formation of hypernuclei in peripheral collisions of relativistic light and heavy ions is studied theoretically within the transport and statistical approaches. New mechanisms for the formation of strange nuclear systems via capture of hyperons by slightly excited spectator matter and their subsequent disintegration are investigated. These processes lead to production of specific and exotic hypernuclei, which may not be accessible in other reactions. Similar mechanisms processing via absorption of strange particles by nuclei can take place in reactions initiated by electrons, antiprotons and other hadrons. It is demonstrated that our approach is consistent with experimental data.

Positive ion scavenging by olefins in trans-decalin: TRMC and product analysis studies

International Nuclear Information System (INIS)

Warman, J.M.; Leng, H.C. de; Haas, M.P. de; Anisimov, O.A.

1990-01-01

The rate constants for scavenging of the mobile positive ion in trans-decalin have been measured using the time-resolved microwave conductivity (TRMC) pulse radiolysis technique for a series of olefins and cyclopropane. For the olefins the values vary from ≤2 x 10 8 dm 3 /mol/s for ethylene to 1.6 x 10 11 dm 3 /mol/s for cyclohexene. Steady-state (γ) radiolysis of solutions of isobutene in trans-decalin results in the formation of isobutane and C 8 and C 14 products which display different dependences on solute concentration. The results are explained in terms of the formation of a complex between the solvent radical cation and isobutene which can dissociate, within a timescale of approx. 1 ns, to give isobutane or on neutralisation leads to the formation of C 14 condensation products. The C 8 products which are formed above 5 x 10 -2 mol/dm 3 are attributed to reaction of the complex with isobutene to form the olefin dimer cation. Cyclopropane is unreactive, i.e. k 8 dm 3 /mol/s, towards the mobile positive ion in trans-decalin (author)

Thin and thick targets for radioactive ion beam production at SPIRAL1 facility

Science.gov (United States)

Jardin, P.; Bajeat, O.; Delahaye, P.; Dubois, M.; Kuchi, V.; Maunoury, L.

2018-05-01

The upgrade of the Système de Production d'Ions Radioactifs Accélérés en Ligne (SPIRAL1) facility will deliver its new Radioactive Ion Beams (RIB) by summer 2017. The goal of the upgrade is an improvement of the performances of the installation in terms of isotopes species and ion charge states [1]. Ion beams are produced using the Isotope Separator On Line Method, consisting in an association of a primary beam of stable ions, a hot target and an ion source. The primary beam impinges on the material of the target. Radioactive isotopes are produced by nuclear reactions and propagate up to the source, where they are ionized and accelerated to create a RIB. One advantage of SPIRAL1 driver is the variety of its available primary beams, from carbon to uranium with energies up to 95 MeV/A. Within the SPIRAL1 upgrade, they will be combined with targets made of a large choice of materials, extending in this way the number of possible nuclear reactions (fusion-evaporation, transfer, fragmentation) for producing a wider range of isotopes, up to regions of the nuclide chart still scarcely explored. Depending on the reaction process, on the collision energy and on the primary beam power, thin and thick targets are used. As their functions can be different, their design must cope with specific constraints which will be described. After a presentation of the goals of present and future SPIRAL1 Target Ion Source System, the main target features, studies and designs under progress are presented.

Design of a helicon plasma source for ion–ion plasma production

Energy Technology Data Exchange (ETDEWEB)

Sharma, N., E-mail: narayan.sharma@cppipr.res.in; Chakraborty, M.; Neog, N.K.; Bandyopadhyay, M.

2017-04-15

Highlights: • Development of a helicon plasma system to carry out ion–ion plasma studies in electronegative gases such as Hydrogen, Oxygen and Chlorine. • Determination of initial parameters of helicon plasma source for ion–ion plasma by using dispersion relation of bounded helicon waves. • Design and development of solenoid with magnetic field strength production capability of ∼ 600 G along the axis of the chamber. • Optimization of the chamber parameters using Helic codes and estimation of optimum attainable density. • Estimation of RF power requirements for various gases. - Abstract: A helicon plasma system is being designed and developed at CPP-IPR. The design parameters of the system are deduced from the dispersion relation of bounded helicon waves and the required magnetic fields are simulated by using Poisson Superfish code. The Helic code is used to simulate the power deposition profile for various conditions and to investigate the optimum values of chamber parameters for effective coupling of radio frequency (RF) power to plasma. The helicon source system is aimed at carrying out ion–ion plasma studies in electronegative gases such as Hydrogen, Oxygen and Chlorine. The system mainly consists of a source chamber in which helicon plasma will be produced by injecting RF power at a frequency of 13.56 MHz through a right helical antenna in presence of a DC magnetic field followed by an expansion chamber in which it is expected to produce negative ions along with the positive ions. Installation of the various parts of the system is in progress. The details of the design and development of the system is presented in this article.

On experimental and theoretical studies of dynamics and particle production in p-nucleus and heavy ion reactions

Energy Technology Data Exchange (ETDEWEB)

Fokin, A.B

1998-11-01

Several experiments and theoretical models of intermediate energy heavy ion collision physics are presented in this thesis. Statistical and dynamical aspects of nuclear collisions are widely discussed these days, particularly in connection with the multifragmentation phenomenon and the possible link to a liquid-gas phase transition in the spinodal region of nuclear matter phase diagram. Experimental techniques which allow us to measure various parameters of hot and dense (equilibrated) regions (emission sources) formed in a heavy ion collision are well established nowadays. In recent CHIC (Celsius Heavy Ion Collaboration) experiments the properties of such sources were measured using slowly ramping mode of the CELSIUS storage ring. In this thesis the entropy and chaos production in nuclear collisions is discussed in connection with the t/d/p ratios. Subthreshold pion production explores collective effects in heavy ion collisions and brings additional information about the equation of state of nuclear matter. Continuous pion production excitation functions were measured in the beam energy region from far below the nucleon-nucleon threshold up to the delta dominant region. Mass and angular dependencies of pion production are discussed. A version of the molecular dynamics model which includes pion production in direct nucleon-nucleon collisions was developed and experimental data were analysed in the scope of this model. Properties of the emission sources formed in heavy ion collisions at energies below 50A MeV were studied in the experiments of fragmentation type performed by CHIC. Temperatures of these sources were extracted from fragment energy spectra and from `isotopic effect`. A version of the quantum molecular dynamics model, where the Pauli potential is introduced into the Hamiltonian, was combined with the statistical multifragmentation model and used to explore dynamical and statistical properties of the reaction development. The artificial neural networks

On experimental and theoretical studies of dynamics and particle production in p-nucleus and heavy ion reactions

International Nuclear Information System (INIS)

Fokin, A.B.

1998-11-01

Several experiments and theoretical models of intermediate energy heavy ion collision physics are presented in this thesis. Statistical and dynamical aspects of nuclear collisions are widely discussed these days, particularly in connection with the multifragmentation phenomenon and the possible link to a liquid-gas phase transition in the spinodal region of nuclear matter phase diagram. Experimental techniques which allow us to measure various parameters of hot and dense (equilibrated) regions (emission sources) formed in a heavy ion collision are well established nowadays. In recent CHIC (Celsius Heavy Ion Collaboration) experiments the properties of such sources were measured using slowly ramping mode of the CELSIUS storage ring. In this thesis the entropy and chaos production in nuclear collisions is discussed in connection with the t/d/p ratios. Subthreshold pion production explores collective effects in heavy ion collisions and brings additional information about the equation of state of nuclear matter. Continuous pion production excitation functions were measured in the beam energy region from far below the nucleon-nucleon threshold up to the delta dominant region. Mass and angular dependencies of pion production are discussed. A version of the molecular dynamics model which includes pion production in direct nucleon-nucleon collisions was developed and experimental data were analysed in the scope of this model. Properties of the emission sources formed in heavy ion collisions at energies below 50A MeV were studied in the experiments of fragmentation type performed by CHIC. Temperatures of these sources were extracted from fragment energy spectra and from 'isotopic effect'. A version of the quantum molecular dynamics model, where the Pauli potential is introduced into the Hamiltonian, was combined with the statistical multifragmentation model and used to explore dynamical and statistical properties of the reaction development. The artificial neural networks

Visualization and Dissemination of Multidimensional Proteomics Data Comparing Protein Abundance During Caenorhabditis elegans Development

Science.gov (United States)

Riffle, Michael; Merrihew, Gennifer E.; Jaschob, Daniel; Sharma, Vagisha; Davis, Trisha N.; Noble, William S.; MacCoss, Michael J.

2015-11-01

Regulation of protein abundance is a critical aspect of cellular function, organism development, and aging. Alternative splicing may give rise to multiple possible proteoforms of gene products where the abundance of each proteoform is independently regulated. Understanding how the abundances of these distinct gene products change is essential to understanding the underlying mechanisms of many biological processes. Bottom-up proteomics mass spectrometry techniques may be used to estimate protein abundance indirectly by sequencing and quantifying peptides that are later mapped to proteins based on sequence. However, quantifying the abundance of distinct gene products is routinely confounded by peptides that map to multiple possible proteoforms. In this work, we describe a technique that may be used to help mitigate the effects of confounding ambiguous peptides and multiple proteoforms when quantifying proteins. We have applied this technique to visualize the distribution of distinct gene products for the whole proteome across 11 developmental stages of the model organism Caenorhabditis elegans. The result is a large multidimensional dataset for which web-based tools were developed for visualizing how translated gene products change during development and identifying possible proteoforms. The underlying instrument raw files and tandem mass spectra may also be downloaded. The data resource is freely available on the web at http://www.yeastrc.org/wormpes/.

Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System

Directory of Open Access Journals (Sweden)

Philippe Boduch

2011-01-01

Full Text Available Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc. of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.

Multiply charged carbon-ion production for medical application

International Nuclear Information System (INIS)

Kitagawa, A.; Muramatsu, M.; Sasaki, N.; Takasugi, W.; Wakaisami, S.; Biri, S.; Drentje, A. G.

2008-01-01

Over 3000 cancer patients have already been treated by the heavy-ion medical accelerator in Chiba at the National Institute of Radiological Sciences since 1994. The clinical results have clearly verified the effectiveness and safety of heavy-ion radiotherapy. The most important result has been to establish that the carbon ion is one of the most effective radiations for radiotherapy. The ion source is required to realize a stable beam with the same conditions for daily operation. However, the deposition of carbon ions on the wall of the plasma chamber is normally unavoidable. This causes an ''anti-wall-coating effect,'' i.e., a decreasing of the beam, especially for the higher charge-state ions due to the surface material of the wall. The ion source must be required to produce a sufficiently intense beam under the bad condition. Other problems were solved by improvements and maintenance, and thus we obtained enough reproducibility and stability along with decreased failures. We summarize our over 13 years of experience, and show the scope for further developments

The abundant excess heat production during low energy nuclear reaction in the nano scale solid state the cold fusion, 14 years' legacy

International Nuclear Information System (INIS)

Woo, Tae Ho; Miley, George H.; Lipson, Andrei; Kim, Sung O.; Luo, Nie; Castano, Carlos H.

2002-01-01

The quite abundant excess heat and radioactive materials are found during the solid state reaction. This phenomenon has done during the Low Energy Nuclear Reaction (LENR) in the nano scale molecular structure electrodes and Hydrogen compound electrolytes. The Palladium (or Nickel) and Platinum are incorporated as the electrode and the Light Water (H 2 O) as the electrolyte. The excess heat was produced up to 40% in year 2001. The Alpha particles are also detected. The computer code, Coherent Lattice Accelerator Inter-Ionic Reaction Enhancer (CLAIRE) Code System, is constructed for the simulation. The 0.1 A of the distance between two the Hydrogen ion (proton) and Palladium nucleus is the critical point for the nuclear fusion reaction

Impact-parameter dependence of the electromagnetic particle production in ultrarelativistic heavy-ion collisions

International Nuclear Information System (INIS)

Vidovic, M.; Greiner, M.; Best, C.; Soff, G.

1992-08-01

The cross section for the electromagentic production of different particles in heavy-ion collision is derived within the external field approach. The underlying assumption leading to the equivalent photon method is that the transverse components of the virtual photon momenta are small compared to their longitudinal components. Introducing polarized photon-fusion cross sections, it is possible to generalize the equivalent photon method to describe the impact- parameter dependence of the particle production. The impact- parameter dependent production of scalar and pseudoscalar (spin 0) bosons, charged (spin 0) boson pairs and fermion pairs is discussed in general. (orig.)

Pion production differential cross section of heavy-ion collisions at subthreshold energies

International Nuclear Information System (INIS)

Abumurad, K.M.

1987-01-01

A revised model for pion production in heavy-ion peripheral collisions at subthreshold energies is presented. The pion-production mechanism investigated here is a two step process involving the formation and subsequent decay of an isobar resonance in the projectile nucleus. The independent-particle shell model with harmonic oscillator states is used to approximate the internal structure of the nucleus. The pion production cross section shows a definite angular distribution characteristic of coherent production. It also gives an indication of the quantum signature of the emitted pions. The results show the disappearance of the quantum signature from the energy spectra because of the inclusion of higher order multipoles. The theory is compared to recent experimental data. The comparison reveals that the general trend is reproduced, which is encouraging

Urbanization Alters the Influence of Weather and an Index of Forest Productivity on Avian Community Richness and Guild Abundance in the Seattle Metropolitan Area

Directory of Open Access Journals (Sweden)

Benjamin Shryock

2017-05-01

Full Text Available Fluctuations in weather and forest productivity influence the abundance and richness of bird populations, however in a rapidly urbanizing landscape the relative importance of each factor may vary. We assessed this possibility in the Seattle, WA, USA region by correlating 10 years of bird richness and relative abundance of nine guilds indicative of their tolerance of human development, migration, diet and use of human food subsidies with an annual index of forest productivity (vegetation greenness derived from a 250 m resolution Normalized Difference Vegetation Index (NDVI product from the MODIS satellite and weather (variation in the Oceanic Niño Index, which estimates the strength of the El Niño-Southern Oscillation, a major driver of local temperature and precipitation. We found that variation in NDVI exerted a strong influence on the richness of the avian community and the abundance of guilds in landscapes undergoing active development, but was less influential in areas of established housing development or forested reserves. Relative to NDVI, weather was much less influential on the abundance of guilds at actively changing sites, and slightly more influential in forest reserves and established developments. Following the warm winter and during the dry summer associated with a strong El Niño, migrants and herbivores declined in changing landscapes, insectivores declined in established developments, and herbivores declined while synanthropic species increased in reserves. These changes may presage the effects of climate change in the Pacific Northwest, which are expected to be similar to El Niño conditions. To buffer these changes in native bird communities, planners, developers, regulators, and home owners should minimize the loss of vegetation during development and attempt to quickly achieve mature landscaping that preferably provides food and shelter for birds.

Production of pions and anomalous projectile fragments in heavy ion collisions

International Nuclear Information System (INIS)

Noren, B.

1988-05-01

Results are presented from investigations of the mean free path (mfp) of multiply charged fragments, produced by 1.8 A GeV argon nuclei. The mfp's have been studied experimentally, and no dependence of the mfp on the distance from the preceeding collision is observed. In a Monte Carlo simulation, the mfp estimators are investigated for different statistics, with or without an enhanced reaction probability. Intermediate energy heavy ion collisions have been studied using the carbon beam produced at the CERN SC-accelerator. Cross-sections for pion + and pion - have been measured over a wide range of angles and targets. Also, coincidence measurements with projectile-like fragments have been performed. The pion - /pion + ratio has been studied for C+Li, C+C, C+Pb, C+ 116 Sn and C+ 124 Sn. Inconsistencies in the target mass dependence of the pion yield disappear if a correction for reabsorption in the target nucleus is included. The projectile breakup is significantly stronger for pion producing collisions than for the average collision, thus indicating a much stronger abundance of central collisions. (With 32 refs.) (author)

Poly-ethers from Winogradskyella poriferorum: Antifouling potential, time-course study of production and natural abundance

KAUST Repository

Dash, Swagatika

2011-08-01

A sponge-associated bacterium, Winogradskyella poriferorum strain UST030701-295T was cultured up to 100l for extraction of antifouling bioactive compounds. Five poly-ethers were isolated and partially characterized based on nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS); two of them showed inhibitory effects on biofilm formation of marine bacteria and larval settlement of macro-foulers but did not produce any adverse effects on the phenotypes of zebra fish embryos at a concentration of 5μgml -1. The effect of culture duration on the production of the poly-ethers and the bioactivity of the relevant extracts was monitored over a period of 12days. The total crude poly-ether production increased from day 2 to day 5 and the highest bioactivity was observed on day 3. The poly-ethers were found to be localized in the cellular fraction of the extracts, implying their natural occurrence. The potent bioactivity of these poly-ethers together with their high natural abundance in bacteria makes them promising candidates as ingredients in antifouling applications. © 2011 Elsevier Ltd.

Investigation of Uranyl Nitrate Ion Pairs Complexed with Amide Ligands using Electrospray Ionization Ion Trap Mass Spectrometry and Density Functional Theory

International Nuclear Information System (INIS)

Groenewold, Gary S.; Dinescu, Adriana; Benson, Michael T.; Gresham, Garold L.; van Stipdonk, Michael J.

2011-01-01

Ion populations formed from electrospray of uranyl nitrate solutions containing different amides vary depending on ligand nucleophilicity and steric crowding at the metal center. The most abundant species were ion pair complexes having the general formula (UO2(NO3)(amide)n=2,3)+, and complexes containing the amide conjugate base, reduced uranyl UO2+, and a 2+ charge were also formed. The formamide experiment produced the greatest diversity of species that stems from weaker amide binding leading to dissociation and subsequent solvent coordination or metal reduction. Experiments using methyl formamide, dimethyl formamide, acetamide, and methyl acetamide produced ion pair and doubly charged complexes that were more abundant, and less abundant complexes containing solvent or reduced uranyl. This pattern is reversed in the dimethylacetamide experiment, which displayed reduced doubly charged complexes and augmented reduced uranyl complexes. DFT investigations of the tris-amide ion pair complexes showed that inter-ligand repulsion distorts the amide ligands out of the uranyl equatorial plane, and that complex stabilities do not increase with increasing amide nucleophilicity. Elimination of an amide ligand largely relieves the interligand repulsion, and the remaining amide ligands become closely aligned with the equatorial plane in the structures of the bis-amide ligands. The studies show that the phenomenological distribution of coordination complexes in a metal-ligand electrospray experiment is a function of both ligand nucleophilicity and interligand repulsion, and that the latter factor begins exerting influence even in the case of relatively small ligands like the substituted methyl-formamide and methyl-acetamide ligands.

Helium abundance and speed difference between helium ions and protons in the solar wind from coronal holes, active regions, and quiet Sun

Science.gov (United States)

Fu, Hui; Madjarska, M. S.; Li, Bo; Xia, LiDong; Huang, ZhengHua

2018-05-01

Two main models have been developed to explain the mechanisms of release, heating and acceleration of the nascent solar wind, the wave-turbulence-driven (WTD) models and reconnection-loop-opening (RLO) models, in which the plasma release processes are fundamentally different. Given that the statistical observational properties of helium ions produced in magnetically diverse solar regions could provide valuable information for the solar wind modelling, we examine the statistical properties of the helium abundance (AHe) and the speed difference between helium ions and protons (vαp) for coronal holes (CHs), active regions (ARs) and the quiet Sun (QS). We find bimodal distributions in the space of AHeand vαp/vA(where vA is the local Alfvén speed) for the solar wind as a whole. The CH wind measurements are concentrated at higher AHeand vαp/vAvalues with a smaller AHedistribution range, while the AR and QS wind is associated with lower AHeand vαp/vA, and a larger AHedistribution range. The magnetic diversity of the source regions and the physical processes related to it are possibly responsible for the different properties of AHeand vαp/vA. The statistical results suggest that the two solar wind generation mechanisms, WTD and RLO, work in parallel in all solar wind source regions. In CH regions WTD plays a major role, whereas the RLO mechanism is more important in AR and QS.

Understanding Molecular Ion-Neutral Atom Collisions for the Production of Ultracold Molecular Ions

Science.gov (United States)

2016-06-06

2012): 0. doi: 10.1103/PhysRevLett.109.223002 Kuang Chen, Scott T. Sullivan, Wade G. Rellergert, Eric R. Hudson. Measurement of the Coulomb Logarithm...or fellowships for further studies in science, mathematics, engineering or technology fields: Student Metrics This section only applies to graduating...clouds of Ba+ ions and Ca atoms. Due to the strong Coulomb interaction, the Ba+ ions quickly cool the molecular ion translation motion, while the

In-Situ Ion Source Cleaning: Review of Chemical Mechanisms and Evaluation Data at Production Fabs

International Nuclear Information System (INIS)

Kaim, R.; Bishop, S.; Byl, O.; Eldridge, D.; Marganski, P.; Mayer, J.; Sweeney, J.; Yedave, S.; Fuchs, D.; Spreitzer, S.; Vogel, J.; Dunn, J.; Lundquist, P.; Rolland, J.; Romig, T.; Newman, D.; Mitchell, M.; Ditzler, K.

2008-01-01

Since the concept of chemical in-situ ion implanter cleaning was introduced at IIT2006 [1], evaluations of the XeF 2 cleaning technology have taken place or are ongoing at more than 40 production fabs worldwide. Testing has been focused on assessing effects of cleaning in the source arc chamber and extraction regions. In this paper we describe use of the cleaning technology in a production environment and summarize evaluation data showing advantages of the technology for improving ion source life, reducing glitching, improving beam auto-tuning and avoiding species cross-contamination. More details of the evaluations are given in several separate papers submitted to this Conference. We have supplemented the fab production data with laboratory experiments designed to investigate the reactivity of XeF 2 and fundamental aspects of the source deposition and cleaning processes. These experiments are summarized here, and more details can be found in separate papers submitted to this Conference

Ion Dynamics at Shocks: Ion Reflection and Beam Formation at Quasi-perpendicular Shocks

International Nuclear Information System (INIS)

Kucharek, Harald; Moebius, Eberhard

2005-01-01

The physics of collisionless shocks is controlled by the ion dynamics. The generation of gyrating ions by reflection as well as the formation of field-aligned ion beams are essential parts of this dynamic. On the one hand reflection is most likely the first interaction of ions with the shock before they undergo the downstream thermalization process. On the other hand field-aligned ion beams, predominately found at the quasi-perpendicular bow shock, propagate into the distant foreshock region and may create wave activity. We revisit ion reflection, the source and basic production mechanism of field-aligned ion beams, by using multi-spacecraft measurements and contrast these observations with existing theories. Finally, we propose an alternative production mechanism

Ferrous Ion and Medium Composition Effects on Acidogenic Phase in Biobutanol Production from Molasses

Science.gov (United States)

Restiawaty, E.; Grinanda, D.

2017-07-01

Clostridium acetobutylicum B530 has ability to convert sugar into biobutanol through two phases, i.e. acidogenic and solventogenic. This fermentation process is often hampered by high raw material cost and low product yield. In order to suppress the production cost, the molasses, a byproduct of sugar cane process production, was used as carbon source in this research. Molasses has nitrogen content in a small amount, thus could be negating the beef extract component, which is expected not to affect the growth of C. acetobutylicum B530 and also can reduce the production cost. In addition, a certain amount of Fe2+ (ferrous ion), a precursor in the formation of the enzyme ferredoxin, was added to the fermentation medium to contribute in the synthesis of acetyl-CoA, so that the formation of acidogenic products such as butyric acid and acetic acid is affected. This study aimed to investigate the effect of ferrous ion and the medium composition in acidogenic phase. The addition of 20 ppm FeSO4.7H2O in the fermentation medium without beef extract can increase the concentration of butyric acid by 20% at a temperature of 35°C, while acetic acid concentration decreased by 6%. According to those results, it is expected that the product selectivity of butanol will increase in solventogenic phase. In addition, the removal of beef extract in the fermentation medium does not affect the kinetics of growth of C. acetobutylicum B530.

Heavy Flavor Production in Heavy Ion Collisions at CMS

CERN Document Server

Sun, Jian

2016-01-01

Studies of Heavy flavor production are of great interest in heavy ion collisions. In the produced medium, the binding potential between a quark and antiquark in quarkonium is screened by surrounding light quarks and antiquarks. Thus, the various quarkonium states are expected to be melt at different temperatures depending on their binding energies, which allows us to characterize the QCD phase transition. In addition, open heavy flavor production are relevant for flavor-dependence of the in-medium parton energy loss. In QCD, gluons are expected to lose more energy compared to quarks when passing through the QGP due to the larger color charge. Compared to light quarks, heavy quarks are expected to lose less radiative energy because gluon radiation is suppressed at angles smaller than the ratio of the quark mass to its energy. This dead cone effect (and its disappearance at high transverse momentum) can be studied using open heavy flavor mesons and heavy flavor tagged jets. With CMS detector, quarkonia, open he...

Irradiation of astrophysical ice grains by cosmic-ray ions: a REAX simulation study

Science.gov (United States)

Mainitz, Martin; Anders, Christian; Urbassek, Herbert M.

2016-07-01

Context. The impact of cosmic rays on ice grains delivers considerable energy, inducing chemical reactions and molecule ejection. Aims: We study the effects of cosmic ray impact on ice grains, including shock wave expansion, grain heating, molecule fragmentation, formation of chemical reaction products, sputtering and evaporation. Methods: Molecular-dynamics simulations using the REAX potential allow us to follow the processes occurring in the irradiated ice grain; the mechanical, thermal and chemical consequences are simulated. The ice grain consists of a mixture of water, carbon dioxide, methanol and ammonia. The case of 1 keV/nm energy deposition is studied as an example. Results: The ion track emits a shock wave into the ambient grain. Due to the strong heating, abundant molecule fragmentation is observed; several of the fragments either recombine or form new product molecules. Prompt sputtering from the ion track is followed by evaporation from the surface of the heated grain. We present mass spectra of the chemically transformed species in the grain and in the ejecta.

Proceedings of RIKEN BNL Research Center Workshop: Brookhaven Summer Program on Quarkonium Production in Elementary and Heavy Ion Collisions

Energy Technology Data Exchange (ETDEWEB)

Dumitru, A.; Lourenco, C.; Petreczky, P.; Qiu, J., Ruan, L.

2011-08-03

Understanding the structure of the hadron is of fundamental importance in subatomic physics. Production of heavy quarkonia is arguably one of the most fascinating subjects in strong interaction physics. It offers unique perspectives into the formation of QCD bound states. Heavy quarkonia are among the most studied particles both theoretically and experimentally. They have been, and continue to be, the focus of measurements in all high energy colliders around the world. Because of their distinct multiple mass scales, heavy quarkonia were suggested as a probe of the hot quark-gluon matter produced in heavy-ion collisions; and their production has been one of the main subjects of the experimental heavy-ion programs at the SPS and RHIC. However, since the discovery of J/psi at Brookhaven National Laboratory and SLAC National Accelerator Laboratory over 36 years ago, theorists still have not been able to fully understand the production mechanism of heavy quarkonia, although major progresses have been made in recent years. With this in mind, a two-week program on quarkonium production was organized at BNL on June 6-17, 2011. Many new experimental data from LHC and from RHIC were presented during the program, including results from the LHC heavy ion run. To analyze and correctly interpret these measurements, and in order to quantify properties of the hot matter produced in heavy-ion collisions, it is necessary to improve our theoretical understanding of quarkonium production. Therefore, a wide range of theoretical aspects on the production mechanism in the vacuum as well as in cold nuclear and hot quark-gluon medium were discussed during the program from the controlled calculations in QCD and its effective theories such as NRQCD to various models, and to the first principle lattice calculation. The scientific program was divided into three major scientific parts: basic production mechanism for heavy quarkonium in vacuum or in high energy elementary collisions; the

Proceedings of RIKEN BNL Research Center Workshop: Brookhaven Summer Program on Quarkonium Production in Elementary and Heavy Ion Collisions

International Nuclear Information System (INIS)

Dumitru, A.; Lourenco, C.; Petreczky, P.; Qiu, J.; Ruan, L.

2011-01-01

Understanding the structure of the hadron is of fundamental importance in subatomic physics. Production of heavy quarkonia is arguably one of the most fascinating subjects in strong interaction physics. It offers unique perspectives into the formation of QCD bound states. Heavy quarkonia are among the most studied particles both theoretically and experimentally. They have been, and continue to be, the focus of measurements in all high energy colliders around the world. Because of their distinct multiple mass scales, heavy quarkonia were suggested as a probe of the hot quark-gluon matter produced in heavy-ion collisions; and their production has been one of the main subjects of the experimental heavy-ion programs at the SPS and RHIC. However, since the discovery of J/psi at Brookhaven National Laboratory and SLAC National Accelerator Laboratory over 36 years ago, theorists still have not been able to fully understand the production mechanism of heavy quarkonia, although major progresses have been made in recent years. With this in mind, a two-week program on quarkonium production was organized at BNL on June 6-17, 2011. Many new experimental data from LHC and from RHIC were presented during the program, including results from the LHC heavy ion run. To analyze and correctly interpret these measurements, and in order to quantify properties of the hot matter produced in heavy-ion collisions, it is necessary to improve our theoretical understanding of quarkonium production. Therefore, a wide range of theoretical aspects on the production mechanism in the vacuum as well as in cold nuclear and hot quark-gluon medium were discussed during the program from the controlled calculations in QCD and its effective theories such as NRQCD to various models, and to the first principle lattice calculation. The scientific program was divided into three major scientific parts: basic production mechanism for heavy quarkonium in vacuum or in high energy elementary collisions; the

Proceedings of the 'INS workshop on ECR ion sources for multiply-charged heavy ions'

International Nuclear Information System (INIS)

1995-02-01

This workshop was held on December 1 and 2, 1994 at the Institute for Nuclear Study, University of Tokyo. The performance of ion sources is crucial for all researches and applications that use ion beam. The performance of ECR ion sources is strongly dependent on heuristic knowledge and innovation. From these viewpoints, it is useful to exchange information on the status of the existing sources, the performance of the new sources, and the design of the future sources between the source builders and the users. There were unexpected more than 70 participants and 20 contributions. The lectures were given on the present status of NIRS-ECR, SF-ECR, INS ISOL-ECR, RCNP ECR and EBIS ion sources, the production of multiply charged metallic ions with Hyper ECR or by plasma cathode method, the processing of ceramic rods and the ion production with OCTOPUS, the modeling of multi-charged ion production, the design of an advanced minimum B for ECR multi-charged ion source, the design, construction and operation of 18 GHz HiECR ion source, the construction and test operation of JAERI 18 GHz ion source, the design of an ECR ion source for the HIMAC, a 14.5 GHz ECR ion source at RIKEN, TMU 14 GHz ECR ion source, ''NANOGAN'' ECR ion source and its irradiation system, the optimization of the ECR ion source for optically pumped polarized ion source and so on. (K.I.)

Proceedings of the `INS workshop on ECR ion sources for multiply-charged heavy ions`

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-01

This workshop was held on December 1 and 2, 1994 at the Institute for Nuclear Study, University of Tokyo. The performance of ion sources is crucial for all researches and applications that use ion beam. The performance of ECR ion sources is strongly dependent on heuristic knowledge and innovation. From these viewpoints, it is useful to exchange information on the status of the existing sources, the performance of the new sources, and the design of the future sources between the source builders and the users. There were unexpected more than 70 participants and 20 contributions. The lectures were given on the present status of NIRS-ECR, SF-ECR, INS ISOL-ECR, RCNP ECR and EBIS ion sources, the production of multiply charged metallic ions with Hyper ECR or by plasma cathode method, the processing of ceramic rods and the ion production with OCTOPUS, the modeling of multi-charged ion production, the design of an advanced minimum B for ECR multi-charged ion source, the design, construction and operation of 18 GHz HiECR ion source, the construction and test operation of JAERI 18 GHz ion source, the design of an ECR ion source for the HIMAC, a 14.5 GHz ECR ion source at RIKEN, TMU 14 GHz ECR ion source, ``NANOGAN`` ECR ion source and its irradiation system, the optimization of the ECR ion source for optically pumped polarized ion source and so on. (K.I.).

Production of C, N, O, and Ne ions by pulsed ion source and acceleration of these ions in the cyclotron

International Nuclear Information System (INIS)

Nakajima, Hisao; Kohara, Shigeo; Kageyama, Tadashi; Kohno, Isao

1977-01-01

The heavy ion source, of electron bombarded hot cathode type, is usually operated by applying direct current for arc discharge. In order to accelerate Ne 6+ ion in the cyclotron, a pulsed operation of this source was attempted. Ne 6+ and O 6+ ions were accelerated successfully up to 160 MeV and more than 0.1 μA of these ion were extracted from the cyclotron. C 5+ , Ne 7+ and 22 Ne 6+ ions were also extracted with a modest intensity of beam. The intensity of C 4+ , N 4+ , N 5+ , and O 5+ ions was increased about ten times. (auth.)

Gas Chromatographic-Ion Trap Mass Spectrometric Analysis of Volatile Organic Compounds by Ion-Molecule Reactions Using the Electron-Deficient Reagent Ion CCl{3/+}

Science.gov (United States)

Wang, Cheng-Zhong; Su, Yue; Wang, Hao-Yang; Guo, Yin-Long

2011-10-01

When using tetrachloromethane as the reagent gas in gas chromatography-ion trap mass spectrometry equipped with hybrid ionization source, the cation CCl{3/+} was generated in high abundance and further gas-phase experiments showed that such an electron-deficient reagent ion CCl{3/+} could undergo interesting ion-molecule reactions with various volatile organic compounds, which not only present some informative gas-phase reactions, but also facilitate qualitative analysis of diverse volatile compounds by providing unique mass spectral data that are characteristic of particular chemical structures. The ion-molecule reactions of the reagent ion CCl{3/+} with different types of compounds were studied, and results showed that such reactions could give rise to structurally diagnostic ions, such as [M + CCl3 - HCl]+ for aromatic hydrocarbons, [M - OH]+ for saturated cyclic ether, ketone, and alcoholic compounds, [M - H]+ ion for monoterpenes, M·+ for sesquiterpenes, [M - CH3CO]+ for esters, as well as the further fragment ions. The mechanisms of ion-molecule reactions of aromatic hydrocarbons, aliphatic ketones and alcoholic compounds with the reagent ion CCl{3/+} were investigated and proposed according to the information provided by MS/MS experiments and theoretical calculations. Then, this method was applied to study volatile organic compounds in Dendranthema indicum var. aromaticum and 20 compounds, including monoterpenes and their oxygen-containing derivatives, aromatic hydrocarbon and sesquiterpenes were identified using such ion-molecule reactions. This study offers a perspective and an alternative tool for the analysis and identification of various volatile compounds.

Production of lithium positive ions from LiF thin films on the anode in PBFA II

International Nuclear Information System (INIS)

Green, T.A.; Stinnett, R.W.; Gerber, R.A.

1995-09-01

The production of positive lithium ions using a lithium-fluoride-coated stainless steel anode in the particle beam fusion accelerator PBFA II is considered from both the experimental and theoretical points of view. It is concluded that the mechanism of Li + ion production is electric field desorption from the tenth-micron-scale crystallites which compose the columnar growth of the LiF thin film. The required electric field is estimated to be of the order of 5 MV/cm. An essential feature of the mechanism is that the crystallites are rendered electronically conducting through electron-hole pair generation by MeV electron bombardment of the thin film during the operation of the diode. It is proposed that the ion emission mechanism is an electronic conductivity analogue to that discovered by Rollgen for lithium halide crystallites which were rendered ionically conducting by heating to several hundred degrees Celsius. Since an electric field desorption mechanism cannot operate if a surface flashover plasma has formed and reduced the anode electric field to low values, the possibility of flashover on the lithium fluoride coated anode of the PBFA II Li + ion source is studied theoretically. It is concluded with near certainty that flashover does not occur

Physics of intense light ion beams and production of high energy density in matter. Annual report 1994

International Nuclear Information System (INIS)

Bluhm, H.J.

1995-06-01

This report presents the results obtained in 1994 within the FZK-program on 'Physics of intense ion beams and pulsed plasmas'. It describes the present status of the 6 MW, 2 TW pulsed generator KALIF-HELIA, the production and focussing of high power ion beams and numerical simulations and experiments related to the hydrodynamics of beam matter interaction. (orig.) [de

Mass spectrometry analysis of etch products from CR-39 plastic irradiated by heavy ions

Science.gov (United States)

Kodaira, S.; Nanjo, D.; Kawashima, H.; Yasuda, N.; Konishi, T.; Kurano, M.; Kitamura, H.; Uchihori, Y.; Naka, S.; Ota, S.; Ideguchi, Y.; Hasebe, N.; Mori, Y.; Yamauchi, T.

2012-09-01

As a feasibility study, gas chromatography-mass spectrometry (GC-MS) and matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) have been applied to analyze etch products of CR-39 plastic (one of the most frequently used solid states nuclear track detector) for the understanding of track formation and etching mechanisms by heavy ion irradiation. The etch products of irradiated CR-39 dissolved in sodium hydroxide solution (NaOH) contain radiation-induced fragments. For the GC-MS analysis, we found peaks of diethylene glycol (DEG) and a small but a definitive peak of ethylene glycol (EG) in the etch products from CR-39 irradiated by 60 MeV N ion beams. The etch products of unirradiated CR-39 showed a clear peak of DEG, but no other significant peaks were found. DEG is known to be released from the CR-39 molecule as a fragment by alkaline hydrolysis reaction of the polymer. We postulate that EG was formed as a result of the breaking of the ether bond (C-O-C) of the DEG part of the CR-39 polymer by the irradiation. The mass distribution of polyallylalcohol was obtained from the etch products from irradiated and unirradiated CR-39 samples by MALDI-MS analysis. Polyallylalcohol, with the repeating mass interval of m/z = 58 Da (dalton) between m/z = 800 and 3500, was expected to be produced from CR-39 by alkaline hydrolysis. We used IAA as a matrix to assist the ionization of organic analyte in MALDI-MS analysis and found that peaks from IAA covered mass spectrum in the lower m/z region making difficult to identify CR-39 fragment peaks which were also be seen in the same region. The mass spectrometry analysis using GC-MS and MALDI-MS will be powerful tools to investigate the radiation-induced polymeric fragments and helping to understand the track formation mechanism in CR-39 by heavy ions.

Discrimination of Isomers of Released N- and O-Glycans Using Diagnostic Product Ions in Negative Ion PGC-LC-ESI-MS/MS

Science.gov (United States)

Ashwood, Christopher; Lin, Chi-Hung; Thaysen-Andersen, Morten; Packer, Nicolle H.

2018-03-01

Profiling cellular protein glycosylation is challenging due to the presence of highly similar glycan structures that play diverse roles in cellular physiology. As the anomericity and the exact linkage type of a single glycosidic bond can influence glycan function, there is a demand for improved and automated methods to confirm detailed structural features and to discriminate between structurally similar isomers, overcoming a significant bottleneck in the analysis of data generated by glycomics experiments. We used porous graphitized carbon-LC-ESI-MS/MS to separate and detect released N- and O-glycan isomers from mammalian model glycoproteins using negative mode resonance activation CID-MS/MS. By interrogating similar fragment spectra from closely related glycan isomers that differ only in arm position and sialyl linkage, product fragment ions for discrimination between these features were discovered. Using the Skyline software, at least two diagnostic fragment ions of high specificity were validated for automated discrimination of sialylation and arm position in N-glycan structures, and sialylation in O-glycan structures, complementing existing structural diagnostic ions. These diagnostic ions were shown to be useful for isomer discrimination using both linear and 3D ion trap mass spectrometers when analyzing complex glycan mixtures from cell lysates. Skyline was found to serve as a useful tool for automated assessment of glycan isomer discrimination. This platform-independent workflow can potentially be extended to automate the characterization and quantitation of other challenging glycan isomers. [Figure not available: see fulltext.

Bi-Abundance Ionisation Structure of the Wolf-Rayet Planetary Nebula PB 8

Science.gov (United States)

Danehkar, A.

2018-01-01

The planetary nebula PB 8 around a [WN/WC]-hybrid central star is one of planetary nebulae with moderate abundance discrepancy factors (ADFs 2-3), which could be an indication of a tiny fraction of metal-rich inclusions embedded in the nebula (bi-abundance). In this work, we have constructed photoionisation models to reproduce the optical and infrared observations of the planetary nebula PB 8 using a non-LTE stellar model atmosphere ionising source. A chemically homogeneous model initially used cannot predict the optical recombination lines. However, a bi-abundance model provides a better fit to most of the observed optical recombination lines from N and O ions. The metal-rich inclusions in the bi-abundance model occupy 5.6% of the total volume of the nebula, and are roughly 1.7 times cooler and denser than the mean values of the surrounding nebula. The N/H and O/H abundance ratios in the metal-rich inclusions are 1.0 and 1.7 dex larger than the diffuse warm nebula, respectively. To reproduce the Spitzer spectral energy distribution of PB 8, dust grains with a dust-to-gas ratio of 0.01 (by mass) were also included. It is found that the presence of metal-rich inclusions can explain the heavy element optical recombination lines, while a dual-dust chemistry with different grain species and discrete grain sizes likely produces the infrared continuum of this planetary nebula. This study demonstrates that the bi-abundance hypothesis, which was examined in a few planetary nebulae with large abundance discrepancies (ADFs > 10), could also be applied to those typical planetary nebulae with moderate abundance discrepancies.

Industrialization and production of neutral beam ion sources for MFTF

International Nuclear Information System (INIS)

Lynch, W.S.

1981-01-01

The existing LLNL designs of the 20 and 80kV deuterium fueled Neutral Beam Ion Source Modules (NBSM) have been industrialized and are being produced successfully for the MFTF. Industrialization includes value engineering, production engineering, cost reduction, fixturing, facilitation and procurement of components. Production assembly, inspection and testing is being performed in a large electronics manufacturing plant. Decades of experience in high voltage, high vacuum power tubes is being applied to the procedures and processes. Independent quality and reliability assurance criteria are being utilized. Scheduling of the various engineering, procurement and manufacturing task is performed by the use of a Critical Path Method (CPM) computer code, Innovative, computerized grid alignment methods were also designed and installed specifically for this project. New jointing and cleaning techniques were devised for the NBSMs. Traceability and cost control are also utilized

The abundant excess heat production during low energy nuclear reaction in the nano scale solid state the cold fusion, 14 years' legacy

Energy Technology Data Exchange (ETDEWEB)

Woo, Tae Ho; Miley, George H.; Lipson, Andrei; Kim, Sung O.; Luo, Nie; Castano, Carlos H. [The University of Illinois, Urbana (United States)

2002-05-01

The quite abundant excess heat and radioactive materials are found during the solid state reaction. This phenomenon has done during the Low Energy Nuclear Reaction (LENR) in the nano scale molecular structure electrodes and Hydrogen compound electrolytes. The Palladium (or Nickel) and Platinum are incorporated as the electrode and the Light Water (H{sub 2}O) as the electrolyte. The excess heat was produced up to 40% in year 2001. The Alpha particles are also detected. The computer code, Coherent Lattice Accelerator Inter-Ionic Reaction Enhancer (CLAIRE) Code System, is constructed for the simulation. The 0.1 A of the distance between two the Hydrogen ion (proton) and Palladium nucleus is the critical point for the nuclear fusion reaction.

The abundance determination in a stellar atmosphere. Pt. 1

International Nuclear Information System (INIS)

Dumont, S.; Heidmann, N.; Pecker, J.C.; Jefferies, J.T.

1975-01-01

It is shown that the classical LTE analysis of an atomic spectrum of a solar-like star leads to values of the abundance A which may be different from the real values. Various uncertainties affect the results derived from neutral lines. However, proper selection of the observational data, for instance use of ion lines, can lead, in similar cases at least, to good values of A. These conclusions concern the solar-like case; however, they emphasize that, in all cases, the effect of departures from LTE needs very careful discussion. (orig.) [de

Single ion hit detection set-up for the Zagreb ion microprobe

Science.gov (United States)

Smith, R. W.; Karlušić, M.; Jakšić, M.

2012-04-01

Irradiation of materials by heavy ions accelerated in MV tandem accelerators may lead to the production of latent ion tracks in many insulators and semiconductors. If irradiation is performed in a high resolution microprobe facility, ion tracks can be ordered by submicrometer positioning precision. However, full control of the ion track positioning can only be achieved by a reliable ion hit detection system that should provide a trigger signal irrespectively of the type and thickness of the material being irradiated. The most useful process that can be utilised for this purpose is emission of secondary electrons from the sample surface that follows the ion impact. The status report of the set-up presented here is based on the use of a channel electron multiplier (CEM) detector mounted on an interchangable sample holder that is inserted into the chamber in a close geometry along with the sample to be irradiated. The set-up has been tested at the Zagreb ion microprobe for different ions and energies, as well as different geometrical arrangements. For energies of heavy ions below 1 MeV/amu, results show that efficient (100%) control of ion impact can be achieved only for ions heavier than silicon. The successful use of the set-up is demonstrated by production of ordered single ion tracks in a polycarbonate film and by monitoring fluence during ion microbeam patterning of Foturan glass.

Study of heliumlike neon using an electron beam ion trap

International Nuclear Information System (INIS)

Wargelin, B.J.; Kahn, S.M.; Beiersdorfer, P.

1992-01-01

The 2-to-1 spectra of several astrophysically abundant He-like ions are being studied using the Electron Beam Ion Trap (EBIT) at Lawrence Livermore National Laboratory. Spectra are recorded for a broad range of plasma parameters, including electron density, energy, and ionization balance. We describe the experimental equipment and procedure and present some typical data

Cross-linked natural gum resins, when inserted in shampooing product, result infallible to eliminate several metallic ions risky for hair keratin

Directory of Open Access Journals (Sweden)

Martini Lorenzo

2016-04-01

Full Text Available Aims of my research is to herald the method of eliminating Calcium and Magnesium ions that remain onto hair and scalp keratin after washing with common hard water and trivial shampooing products, but even of removing other metals as Lead, Silicon and Nickel ions which can be retrieved in manifold building materials like mortar, cement, concrete, pozzolans, limestone and asbest, most of workers throughout the world are directly involved with, because of their continuous contact with those chemical materials. I have selected twelve volunteers (workers who are directly in contact with building materials containing Calcium and Magnesium ions and prayed them to use three types of shampooing products of my invention (containing special gum resins previously cross-linked in order to uptake or sorption the metallic ions after having used, in precedence, trivial shampoos (bought at the same store and used the same tap water, since they live all in the same town. I calculated the difference of quantities of Magnesium and Calcium that remain onto hair and scalp keratin, using a general and trivial shampoo respect to my products, apt to remove the same metallic ions. Results are satisfactory and encouraging.

Ion source operating at the Unilac injector

International Nuclear Information System (INIS)

Mueller, M.; Jacoby, W.

1977-01-01

The Unilac injection velocity (v = 0.005 X c) and the maximum potential difference between ion source and ground (320 kV) limit positive ion acceleration to a specific charge of not less than 0.0336 (corresponding to 238 U 8+ ). Ion sources qualified for the Unilac must be able to produce a charge spectrum with high intensities in the required charge states (1 - 10 particle μA). This requirement is satisfied for all elements by the Dubna type heated cathode penning ion source. Obviously, for isotopes of low natural abundance high beam currents can only be produced by employing enriched isotopes as feeding materials. Presently the injector is equipped with one penning ion source and one duoplasmatron ion source. 90% of the noble gas ions are provided by the duoplasmatron ion source, whereas ion beams of solids are exclusively furnished by the penning source. In particular, this latter source is well suited and highly developped for producing ion beams from solids by means of the sputtering process. In the future, however, we intend to produce metal ions up to a mass of 100 by a sputter version of the duoplasmatron. (orig.) [de

Abundance of introduced species at home predicts abundance away in herbaceous communities

Science.gov (United States)

Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

2011-01-01

Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

Elemental abundances in nature - fortuity or conformity to natural laws?

International Nuclear Information System (INIS)

Kist, A.A.

1995-01-01

Nuclear analytical methods during the last decades have given a lot of new data on elemental composition of various natural materials. These data allow a return to the question of the regularities of element abundance. This question seems to be important from the point view of basic science as well as analytical chemistry (analytical procedure planning, expected element concentrations, choice of sufficient sensitivity and reproducibility, etc.). The most fruitful approach in this connection is the comparison of the elemental composition of some generalized systems with an element's fundamental characteristics and/or its position in the Periodical System. Stronger correlations can be found when the elemental characteristic (its position in the Periodic Table) versus abundance is considered within separate groups of elements. This idea is illustrated by considering elements' abundance in the Universe, Solar Systems, Earth crust, sea water, soils, plants, etc. Simple equations describe these function with acceptable agreement of tabular and calculated data. The coefficients of these equations in many cases were also connected with some fundamental characteristics such as ionization potential, ion potential, melting and boiling point, etc. (author) 9 refs.; 7 figs

Determination of the Deuterium Abundances in Water from 156 to 10,000 ppm by SIFT-MS

Czech Academy of Sciences Publication Activity Database

Španěl, Patrik; Shestivska, Violetta; Chippendale, T. W. E.; Smith, D.

2011-01-01

Roč. 22, č. 1 (2011), s. 179-186 ISSN 1044-0305 Institutional research plan: CEZ:AV0Z40400503 Keywords : deuterium abundance * total body water * selected ion flow tube mass spectrometry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.002, year: 2011

Chemical composition of waterfall-induced air ions: Spectrometry vs. simulations

Energy Technology Data Exchange (ETDEWEB)

Parts, T.-E.; Luts, A. [Tartu Univ. (Estonia). Dept. of Environmental Physics; Laakso, L.; Hirsikko, A.; Groenholm, T.; Kulmala, M. [Helsinki Univ. (Finland). Dept. of Physical Sciences

2007-07-01

Our measurements of ion size distributions near a waterfall provided new evidence for a waterfall-induced modification of air ion sizes. The ion size spectrum near a waterfall permanently differs from that in ordinary tropospheric air. In this paper we investigated the near-waterfall air ions chemical nature in detail. We carried out a simulation series of air small negative ion evolution, proposing that falling water, as a new environmental component, increases the concentration of OH{sup -} cluster ions. The produced OH{sup -} ions were employed as an extra input for our ion evolution model. The presence of additional OH{sup -} ions resulted in a decrease of typically model-provided NO{sub 3}{sup -} and/or HSO{sub 4}{sup -} cluster ion concentrations and an increase of the abundance of HCO{sub 3}{sup -} cluster ions. Near the waterfall the latter ions became dominant in our simulations. (orig.)

Ion source techniques for high-speed processing of material surface by ion beams

International Nuclear Information System (INIS)

Ishikawa, Junzo

1990-01-01

The present paper discusses some key or candidate techniques for future ion source development and such ion sources developed by the author. Several types of microwave ion sources for producing low charge state ions have been developed in Japan. When a microwave plasma cathode developed by the author is adapted to a Kaufman type ion source, the electron emission currents are found to be 2.5 A for argon gas and 0.5-0.9 A for oxygen gas. An alternative ionization method for metal atoms is strongly required for high-speed processing of material surface by metal-ion beams. Detailed discussion is made of collisional ionization of vaporized atoms, and negative-ion production (secondary negative-ion emission by sputtering). An impregnated electrode type liquid-metal ion source developed by the author, which has a porous tip structure, is described. The negative-ion production efficiency is quite high. The report also presents a neutral and ionized alkaline-metal bombardment type heavy negative-ion source, which consists of a cesium plasma ion source, suppressor, target electrode, negative-ion extraction electrode, and einzel lens. (N.K.)

Large fragment production calculations in relativistic heavy-ion reactions

International Nuclear Information System (INIS)

Seixas de Oliveira, L.F.

1978-12-01

The abrasion-ablation model is briefly described and then used to calculate cross sections for production of large fragments resulting from target or projectile fragmentation in high-energy heavy-ion collisions. The number of nucleons removed from the colliding nuclei in the abrasion stage and the excitation energy of the remaining fragments (primary products) are calculated with the geometrical picture of two different models: the fireball and the firestreak models. The charge-to-mass dispersion of the primary products is calculated using either a model which assumes no correlations between proton and neutron positions inside the nucleus (hypergeometric distribution) or a model based upon the zero-point oscillations of the giant dipole resonance (NUC-GDR). Standard Weisskopf--Ewing statistical evaporation calculations are used to calculate final product distributions. Results of the pure abrasion-ablation model are compared with a variety of experimental data. The comparisons show the insufficiency of the extra-surface energy term used in the abrasion calculations. A frictional spectator interaction (FSI) is introduced which increases the average excitation energy of the primary products, and improves the results considerably in most cases. Agreements and discrepancies of the results calculated with the different theoretical assumptions and the experimental data are studied. Of particular relevance is the possibility of observing nuclear ground-state correlations.Results of the recently completed experiment of fragmentation of 213 Mev/A 40 Ar projectiles are studied and shown not to be capable of answering that question unambiguously. But predictions for the upcoming 48 Ca fragmentation experiment clearly show the possibility of observing correlation effects. 78 references

Simultaneous production of spin-polarized ions/electrons based on two-photon ionization of laser-ablated metallic atoms

International Nuclear Information System (INIS)

Nakajima, Takashi; Yonekura, Nobuaki; Matsuo, Yukari; Kobayashi, Tohru; Fukuyama, Yoshimitsu

2003-01-01

We demonstrate the simultaneous production of spin-polarized ions/electrons using two-color, two-photon ionization of laser-ablated metallic atoms. Specifically, we have applied the developed technique to laser-ablated Sr atoms, and found that the electron-spin polarization of Sr + ions, and accordingly, the spin polarization of photoelectrons is 64%±9%, which is in good agreement with the theoretical prediction we have recently reported [T. Nakajima and N. Yonekura, J. Chem. Phys. 117, 2112 (2002)]. Our experimental results open up a simple way toward the construction of a spin-polarized dual ion/electron source

Correlation of precursor and product ions in single-stage high resolution mass spectrometry. A tool for detecting diagnostic ions and improving the precursor elemental composition elucidation

Energy Technology Data Exchange (ETDEWEB)

Borràs, S. [Departament de Química Analítica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Kaufmann, A., E-mail: anton.kaufmann@klzh.ch [Official Food Control Authority, Fehrenstrasse 15, 8032 Zürich (Switzerland); Companyó, R. [Departament de Química Analítica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain)

2013-04-15

Highlights: ► We are describing a technique to spot ions which are derived from each other. ► Single stage high resolution data is used. ► This “in silicon” technique is compared to conventional precursor scan. ► Some applications for this technique are presented. -- Abstract: Monitoring of common diagnostic fragments is essential for recognizing molecules which are members of a particular compound class. Up to now, unit resolving tandem quadrupole mass spectrometers, operating in the precursor ion scan mode, have been typically used to perform such analysis. By means of high-resolution mass spectrometry (HRMS) a much more sensitive and selective detection can be achieved. However, using a single-stage HRMS instrument, there is no unequivocal link to the corresponding precursor ion, since such instrumentation does not permit a previous precursor selection. Thus, to address this limitation, an in silico approach to locate precursor ions, based on diagnostic fragments, was developed. Implemented as an Excel macro, the algorithm rapidly assembles and surveys exact mass data to provide a list of feasible precursor candidates according to the correlation of the chromatographic peak shape profile and other additional filtering criteria (e.g. neutral losses and isotopes). The macro was tested with two families of veterinary drugs, sulfonamides and penicillins, which are known to yield diagnostic product ions when fragmented. Data sets obtained from different food matrices (fish and liver), both at high and low concentration of the target compounds, were investigated in order to evaluate the capabilities and limitations of the reported approach. Finally, other possible applications of this technique, such as the elucidation of elemental compositions based on product ions and corresponding neutral losses, were also presented and discussed.

Correlation of precursor and product ions in single-stage high resolution mass spectrometry. A tool for detecting diagnostic ions and improving the precursor elemental composition elucidation

International Nuclear Information System (INIS)

Borràs, S.; Kaufmann, A.; Companyó, R.

2013-01-01

Highlights: ► We are describing a technique to spot ions which are derived from each other. ► Single stage high resolution data is used. ► This “in silicon” technique is compared to conventional precursor scan. ► Some applications for this technique are presented. -- Abstract: Monitoring of common diagnostic fragments is essential for recognizing molecules which are members of a particular compound class. Up to now, unit resolving tandem quadrupole mass spectrometers, operating in the precursor ion scan mode, have been typically used to perform such analysis. By means of high-resolution mass spectrometry (HRMS) a much more sensitive and selective detection can be achieved. However, using a single-stage HRMS instrument, there is no unequivocal link to the corresponding precursor ion, since such instrumentation does not permit a previous precursor selection. Thus, to address this limitation, an in silico approach to locate precursor ions, based on diagnostic fragments, was developed. Implemented as an Excel macro, the algorithm rapidly assembles and surveys exact mass data to provide a list of feasible precursor candidates according to the correlation of the chromatographic peak shape profile and other additional filtering criteria (e.g. neutral losses and isotopes). The macro was tested with two families of veterinary drugs, sulfonamides and penicillins, which are known to yield diagnostic product ions when fragmented. Data sets obtained from different food matrices (fish and liver), both at high and low concentration of the target compounds, were investigated in order to evaluate the capabilities and limitations of the reported approach. Finally, other possible applications of this technique, such as the elucidation of elemental compositions based on product ions and corresponding neutral losses, were also presented and discussed

Fluoride ions vs removal technologies: A study

OpenAIRE

Singh, Jagvir; Singh, Prashant; Singh, Anuradha

2016-01-01

Literature reported that drinking water is a precious and scarce resource and it has to be protected and kept free from any kind of contamination. Further, it has to be used carefully without wasting. Literature also reported that fluoride bearing rocks are abundant in India, as a result, fluoride leaches out and contaminates the adjacent water and soil resources. A high concentration of fluoride ions in ground water increases up to more than 30 mg/L. This high concentration of fluoride ions ...

Impact-parameter dependence of the total probability for electromagnetic electron-positron pair production in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Hencken, K.; Trautmann, D.; Baur, G.

1995-01-01

We calculate the impact-parameter-dependent total probability P total (b) for the electromagnetic production of electron-positron pairs in relativistic heavy-ion collisions in lowest order. We study expecially impact parameters smaller than the Compton wavelength of the electron, where the equivalent-photon approximation cannot be used. Calculations with and without a form factor for the heavy ions are done; the influence is found to be small. The lowest-order results are found to violate unitarity and are used for the calculation of multiple-pair production probabilities with the help of the approximate Poisson distribution already found in earlier publications

Neutron activation system for spectral measurements of pulsed ion diode neutron production

International Nuclear Information System (INIS)

Hanson, D.L.; Kruse, L.W.

1980-02-01

A neutron energy spectrometer has been developed to study intense ion beam-target interactions in the harsh radiation environment of a relativistic electron beam source. The main component is a neutron threshold activation system employing two multiplexed high efficiency Ge(Li) detectors, an annihilation gamma coincidence system, and a pneumatic sample transport. Additional constraints on the neutron spectrum are provided by total neutron yield and time-of-flight measurements. A practical lower limit on the total neutron yield into 4π required for a spectral measurement with this system is approx. 10 10 n where the neutron yield is predominantly below 4 MeV and approx. 10 8 n when a significant fraction of the yield is above 4 MeV. Applications of this system to pulsed ion diode neutron production experiments on Hermes II are described

Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates

KAUST Repository

Naganuma, Tamaki

2014-01-01

Abundant oxygen vacancies coexisting with Ce3+ ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce3+ ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce3+ ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce3+ and Ce4+ ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce3+ ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce 3+ ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce3+ ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce 3+ to Ce4+ occurred at 350 °C in air. Highly concentrated Ce3+ ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce 3+ stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce3+ sites. This study also illuminates the potential interaction mechanisms of stable Ce3+ ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. © The Royal Society of Chemistry 2014.

Benchmarking of the Oxford Nanopore MinION sequencing for quantitative and qualitative assessment of cDNA populations.

Science.gov (United States)

Oikonomopoulos, Spyros; Wang, Yu Chang; Djambazian, Haig; Badescu, Dunarel; Ragoussis, Jiannis

2016-08-24

To assess the performance of the Oxford Nanopore Technologies MinION sequencing platform, cDNAs from the External RNA Controls Consortium (ERCC) RNA Spike-In mix were sequenced. This mix mimics mammalian mRNA species and consists of 92 polyadenylated transcripts with known concentration. cDNA libraries were generated using a template switching protocol to facilitate the direct comparison between different sequencing platforms. The MinION performance was assessed for its ability to sequence the cDNAs directly with good accuracy in terms of abundance and full length. The abundance of the ERCC cDNA molecules sequenced by MinION agreed with their expected concentration. No length or GC content bias was observed. The majority of cDNAs were sequenced as full length. Additionally, a complex cDNA population derived from a human HEK-293 cell line was sequenced on an Illumina HiSeq 2500, PacBio RS II and ONT MinION platforms. We observed that there was a good agreement in the measured cDNA abundance between PacBio RS II and ONT MinION (rpearson = 0.82, isoforms with length more than 700bp) and between Illumina HiSeq 2500 and ONT MinION (rpearson = 0.75). This indicates that the ONT MinION can sequence quantitatively both long and short full length cDNA molecules.

Production of strange clusters in relativistic heavy ion collisions

International Nuclear Information System (INIS)

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

1993-02-01

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

Production and characterization of phosphorescent nanopowders doped with rare earth ions

International Nuclear Information System (INIS)

Montes, Paulo Jorge Ribeiro

2009-01-01

In this work the feasibility of employing the synthesis process using a methodology developed by Macedo and Sasaki (Macedo, M. A. e Sasaki, J. M. Fabrication process nano particulate powders. INPI 0203876-5 1998) to produce pore and rare earths doped ceramic nano powders of SrAl 2 O 4 and Ca 12 Al 14 O 33 was investigated. In this new methodology, coconut water is used as a start solvent for the production of the samples. Thermal analysis techniques were employed in order to obtain the best calcination conditions. The structural and microstructural characterizations of the samples were made using powder X-ray diffraction and Atomic Force Microscopy techniques. The analysis by X-ray diffraction showed the formation of the SrAl 2 O 4 and Ca 12 Al 14 O 33 phases in the calcined powders. The emission/excitation spectra exhibited the typical transitions of the rare earth elements indicating the incorporation of the dopant in the nano crystals. Emission characteristics of divalent europium show that the reduction of Eu ions is induced during the synthesis stage. The doped samples show an intense bright emission when exposed to X-rays. That emission is associated with divalent europium transitions, indicating that irradiation also induces the reduction of the valence state of Eu ions from Eu 3+ to Eu 2+ . Radioluminescence spectra (RL) versus time show a decay of the RL intensity to 40% of the initial intensity after 20 minutes of exposure to X-rays. Irradiation also causes a change in color of the samples indicating the production of radiation damage. Analysis of the results of X-ray spectroscopy (XAS- X-ray Absorption Spectroscopy) and the luminescent emission of samples excited by X-rays (XEOL - X-ray Excited Optical Luminescence) enabled the creation of a model that explains that behavior. DXAS technique (Dispersive X-ray Absorption Spectroscopy) was used to monitor the kinetics of the reduction process of Eu ions during irradiation, in order to verify the

reSpect: Software for Identification of High and Low Abundance Ion Species in Chimeric Tandem Mass Spectra

Science.gov (United States)

Shteynberg, David; Mendoza, Luis; Hoopmann, Michael R.; Sun, Zhi; Schmidt, Frank; Deutsch, Eric W.; Moritz, Robert L.

2015-11-01

Most shotgun proteomics data analysis workflows are based on the assumption that each fragment ion spectrum is explained by a single species of peptide ion isolated by the mass spectrometer; however, in reality mass spectrometers often isolate more than one peptide ion within the window of isolation that contribute to additional peptide fragment peaks in many spectra. We present a new tool called reSpect, implemented in the Trans-Proteomic Pipeline (TPP), which enables an iterative workflow whereby fragment ion peaks explained by a peptide ion identified in one round of sequence searching or spectral library search are attenuated based on the confidence of the identification, and then the altered spectrum is subjected to further rounds of searching. The reSpect tool is not implemented as a search engine, but rather as a post-search engine processing step where only fragment ion intensities are altered. This enables the application of any search engine combination in the iterations that follow. Thus, reSpect is compatible with all other protein sequence database search engines as well as peptide spectral library search engines that are supported by the TPP. We show that while some datasets are highly amenable to chimeric spectrum identification and lead to additional peptide identification boosts of over 30% with as many as four different peptide ions identified per spectrum, datasets with narrow precursor ion selection only benefit from such processing at the level of a few percent. We demonstrate a technique that facilitates the determination of the degree to which a dataset would benefit from chimeric spectrum analysis. The reSpect tool is free and open source, provided within the TPP and available at the TPP website.

Adsorption of metal ions and acid dyes on brewer's refuse and its crosslinked products; Biru shikomikasu oyobi sono kashikaketai ni taisuru kinzoku ion oyobi sansei senryo no kyuchaku

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Y.; Kubota, Y.; Higashimura, T. [The University of Shiga Prefecture, Shiga (Japan). Department of Materials Sceince; Kawaguchi, M. [Seisui Kogyo Ltd., Osaka (Japan)

2000-01-10

To use brewer's refuse as adsorbent adsorption of metal ions and acid dyes on them and their reaction products with 1,3,5-triacryloylhexahydro-1,3,5-triazine(TAF) were examined. The refuse samples used in the present study are protein rich fraction(Pr) and cellulosics rich fraction(Hr) obtained by sifting brewer's refuse. Adsorptive experiments were conducted by a batchwise method at 303 K. Pr adsorbed more metal ions such as Cr{sup 6+}, Ni{sup 2+}, Co{sup 2+}, especially Fe{sup 3+}, Hg{sup 2+} and Cu{sup 2+} than Hr. But both refuses hardly adsorbed Ca{sup 2+}. Also Pr adsorbed more acid dyes, especially more hydrophobic C. I. Acid Red 88 than C. I. Acid Orange 7- than Hr at pH 5. By crosslinking Pr and Hr using TAF adsorption of acid dyes increased markedly, but adsorption of metal ions decreased. Therefore Pr can be used as adsorbent for acid dyes and metal ions as it is. Moreover the crosslinked products are excellent adsorbents for acid dyes. (author)

Charge-state correlated cross sections for the production of low-velocity highly charged Ne ions by heavy-ion bombardment

International Nuclear Information System (INIS)

Gray, T.J.; Cocke, C.L.; Justiniano, E.

1980-01-01

We report measured cross sections for the collisional production of highly charged low-velocity Ne recoil ions resulting from the bombardment of a thin Ne gas target by highly charged 1-MeV/amu C, N, O, and F projectiles. The measurements were made using time-of-flight techniques which allowed the simultaneous identification of the final charge state of both the low-velocity recoil ion and the high-velocity projectile for each collision event. For a given incident-projectile charge state, the recoil charge-state distribution is very dependent upon the final charge state of the projectile. Single- and double-electron capture events by incident bare nuclei and projectile K-shell ionization during the collision cause large shifts in the recoil charge-state distributions toward higher charge states. A previously proposed energy-deposition model is modified to include the effects of projectile charge-changing collisions during the collision for bare and hydrogenlike projectiles and is used to discuss the present experimental results

Enhanced lipid productivity and photosynthesis efficiency in a Desmodesmus sp. mutant induced by heavy carbon ions.

Science.gov (United States)

Hu, Guangrong; Fan, Yong; Zhang, Lei; Yuan, Cheng; Wang, Jufang; Li, Wenjian; Hu, Qiang; Li, Fuli

2013-01-01

The unicellular green microalga Desmodesmus sp. S1 can produce more than 50% total lipid of cell dry weight under high light and nitrogen-limitation conditions. After irradiation by heavy (12)C(6+) ion beam of 10, 30, 60, 90 or 120 Gy, followed by screening of resulting mutants on 24-well microplates, more than 500 mutants were obtained. One of those, named D90G-19, exhibited lipid productivity of 0.298 g L(-1)⋅d(-1), 20.6% higher than wild type, likely owing to an improved maximum quantum efficiency (Fv/Fm) of photosynthesis under stress. This work demonstrated that heavy-ion irradiation combined with high-throughput screening is an effective means for trait improvement. The resulting mutant D90G-19 may be used for enhanced lipid production.

Heavy-ion radiation chemistry

International Nuclear Information System (INIS)

Imamura, Masashi

1975-01-01

New aspect of heavy ion radiation chemistry is reviewed. Experiment has been carried out with carbon ions and nitrogen ions accelerated by a 160 cm cyclotron of the Institute of Physical and Chemical Research. The results of experiments are discussed, taking into consideration the effects of core radius depending on heavy ion energy and of the branch tracks of secondary electrons outside the core on chemical reaction and the yield of products. The effect of core size on chemical reaction was not able to be observed, because the incident energy of heavy ions was only several tens of MeV. Regarding high radical density, attention must be given to the production of oxygen in the core. It is possible to produce O 2 in the core in case of high linear energy transfer (LET), while no production of O 2 in case of low LET radiation. This may be one of study problems in future. LET effects on the yield of decomposed products were examined on acetone, methyl-ethyl-ketone and diethyl ketone, using heavy ions (C and N) as well as gamma radiation and helium ions. These three ketones showed that the LET change of two gaseous products, H 2 and CO, was THF type. There are peaks at 50-70 eV/A in the yield of both products. The peaks suggest the occurrence of ''saturation'' in decomposition. Attention was drawn to acetone containing a small amount (2 wt.%) of H 2 O. H 2 O and CO produced from this system differ from those in the pure system. The hydrogen connection formed by such a small amount of H 2 O may mediate the energy transfer. Sodium acetate tri-hydrate produces CH 3 radical selectively by gamma-ray irradiation at 77 K. In this case, the production of CH 2 COO - increases with the increase of LET of radiation. This phenomenon may be an important study problem. (Iwakiri, K.)

Variation in Population Synchrony in a Multi-Species Seabird Community: Response to Changes in Predator Abundance.

Directory of Open Access Journals (Sweden)

Gail S Robertson

Full Text Available Ecologically similar sympatric species, subject to typical environmental conditions, may be expected to exhibit synchronous temporal fluctuations in demographic parameters, while populations of dissimilar species might be expected to show less synchrony. Previous studies have tested for synchrony in different populations of single species, and those including data from more than one species have compared fluctuations in only one demographic parameter. We tested for synchrony in inter-annual changes in breeding population abundance and productivity among four tern species on Coquet Island, northeast England. We also examined how manipulation of one independent environmental variable (predator abundance influenced temporal changes in ecologically similar and dissimilar tern species. Changes in breeding abundance and productivity of ecologically similar species (Arctic Sterna paradisaea, Common S. hirundo and Roseate Terns S. dougallii were synchronous with one another over time, but not with a species with different foraging and breeding behaviour (Sandwich Terns Thalasseus sandvicensis. With respect to changes in predator abundance, there was no clear pattern. Roseate Tern abundance was negatively correlated with that of large gulls breeding on the island from 1975 to 2013, while Common Tern abundance was positively correlated with number of large gulls, and no significant correlations were found between large gull and Arctic and Sandwich Tern populations. Large gull abundance was negatively correlated with productivity of Arctic and Common Terns two years later, possibly due to predation risk after fledging, while no correlation with Roseate Tern productivity was found. The varying effect of predator abundance is most likely due to specific differences in the behaviour and ecology of even these closely-related species. Examining synchrony in multi-species assemblages improves our understanding of how whole communities react to long-term changes

Entropy and Multifractality in Relativistic Ion-Ion Collisions

Directory of Open Access Journals (Sweden)

Shaista Khan

2018-01-01

Full Text Available Entropy production in multiparticle systems is investigated by analyzing the experimental data on ion-ion collisions at AGS and SPS energies and comparing the findings with those reported earlier for hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It is observed that the entropy produced in limited and full phase space, when normalized to maximum rapidity, exhibits a kind of scaling which is nicely supported by Monte Carlo model HIJING. Using Rényi’s order q information entropy, multifractal characteristics of particle production are examined in terms of generalized dimensions, Dq. Nearly the same values of multifractal specific heat, c, observed in hadronic and ion-ion collisions over a wide range of incident energies suggest that the quantity c might be used as a universal characteristic of multiparticle production in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. The analysis is extended to the study of spectrum of scaling indices. The findings reveal that Rényi’s order q information entropy could be another way to investigate the fluctuations in multiplicity distributions in terms of spectral function f(α, which has been argued to be a convenient function for comparison sake not only among different experiments but also between the data and theoretical models.

Production of negative helium ions

International Nuclear Information System (INIS)

Toledo, A.S. de; Sala, O.

1977-01-01

A negative helium ion source using potassium charge exchange vapor has been developed to be used as an injector for the Pelletron accelerator. 3 He and α beam currents of up to 2μA have been extracted with 75% particle transmission through the machine [pt

The solar wind neon abundance observed with ACE/SWICS and ULYSSES/SWICS

International Nuclear Information System (INIS)

Shearer, Paul; Raines, Jim M.; Lepri, Susan T.; Thomas, Jonathan W.; Gilbert, Jason A.; Landi, Enrico; Zurbuchen, Thomas H.; Von Steiger, Rudolf

2014-01-01

Using in situ ion spectrometry data from ACE/SWICS, we determine the solar wind Ne/O elemental abundance ratio and examine its dependence on wind speed and evolution with the solar cycle. We find that Ne/O is inversely correlated with wind speed, is nearly constant in the fast wind, and correlates strongly with solar activity in the slow wind. In fast wind streams with speeds above 600 km s –1 , we find Ne/O = 0.10 ± 0.02, in good agreement with the extensive polar observations by Ulysses/SWICS. In slow wind streams with speeds below 400 km s –1 , Ne/O ranges from a low of 0.12 ± 0.02 at solar maximum to a high of 0.17 ± 0.03 at solar minimum. These measurements place new and significant empirical constraints on the fractionation mechanisms governing solar wind composition and have implications for the coronal and photospheric abundances of neon and oxygen. The results are made possible by a new data analysis method that robustly identifies rare elements in the measured ion spectra. The method is also applied to Ulysses/SWICS data, which confirms the ACE observations and extends our view of solar wind neon into the three-dimensional heliosphere.

The solar wind neon abundance observed with ACE/SWICS and ULYSSES/SWICS

Energy Technology Data Exchange (ETDEWEB)

Shearer, Paul; Raines, Jim M.; Lepri, Susan T.; Thomas, Jonathan W.; Gilbert, Jason A.; Landi, Enrico; Zurbuchen, Thomas H. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Von Steiger, Rudolf [International Space Science Institute, Hallerstrasse 6, CH-3012 Bern (Switzerland)

2014-07-01

Using in situ ion spectrometry data from ACE/SWICS, we determine the solar wind Ne/O elemental abundance ratio and examine its dependence on wind speed and evolution with the solar cycle. We find that Ne/O is inversely correlated with wind speed, is nearly constant in the fast wind, and correlates strongly with solar activity in the slow wind. In fast wind streams with speeds above 600 km s{sup –1}, we find Ne/O = 0.10 ± 0.02, in good agreement with the extensive polar observations by Ulysses/SWICS. In slow wind streams with speeds below 400 km s{sup –1}, Ne/O ranges from a low of 0.12 ± 0.02 at solar maximum to a high of 0.17 ± 0.03 at solar minimum. These measurements place new and significant empirical constraints on the fractionation mechanisms governing solar wind composition and have implications for the coronal and photospheric abundances of neon and oxygen. The results are made possible by a new data analysis method that robustly identifies rare elements in the measured ion spectra. The method is also applied to Ulysses/SWICS data, which confirms the ACE observations and extends our view of solar wind neon into the three-dimensional heliosphere.

Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

Directory of Open Access Journals (Sweden)

Raghunath Sahoo

2015-01-01

Full Text Available We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

Growth and abundance of Pacific Sand Lance, Ammodytes hexapterus, under differing oceanographic regimes

Science.gov (United States)

Robards, Martin D.; Gray, Floyd; Piatt, John F.

2002-01-01

Dramatic changes in seabird and marine mammal stocks in the Gulf of Alaska have been linked to shifts in abundance and composition of forage fish stocks over the past 20 years. The relative value (e.g., size and condition of individual fish, abundance) of specific forage fish stocks to predators under temporally changing oceanographic regimes is also expected to vary. We inferred potential temporal responses in abundance, growth, and age structure of a key forage fish, sand lance, by studying across spatially different oceanographic regimes. Marked meso-scale differences in abundance, growth, and mortality existed in conjunction with these differing regimes. Growth rate within stocks (between years) was positively correlated with temperature. However, this relationship did not exist among stocks (locations) and differing growth rates were better correlated to marine productivity. Sand lance were least abundant and grew slowest at the warmest site (Chisik Island), an area of limited habitat and low food abundance. Abundance and growth of juvenile sand lance was highest at the coolest site (Barren Islands), an area of highly productive upwelled waters. Sand lance at two sites located oceanographically between the Barren Islands and Chisik Island (inner- and outer-Kachemak Bay) displayed correspondingly intermediate abundance and growth. Resident predators at these sites are presented with markedly different numbers and quality of this key prey species. Our results suggest that at the decadal scale, Gulf of Alaska forage fish such as sand lance are probably more profoundly affected by changes in abundance and quality of their planktonic food, than by temperature alone.

reSpect: software for identification of high and low abundance ion species in chimeric tandem mass spectra.

Science.gov (United States)

Shteynberg, David; Mendoza, Luis; Hoopmann, Michael R; Sun, Zhi; Schmidt, Frank; Deutsch, Eric W; Moritz, Robert L

2015-11-01

Most shotgun proteomics data analysis workflows are based on the assumption that each fragment ion spectrum is explained by a single species of peptide ion isolated by the mass spectrometer; however, in reality mass spectrometers often isolate more than one peptide ion within the window of isolation that contribute to additional peptide fragment peaks in many spectra. We present a new tool called reSpect, implemented in the Trans-Proteomic Pipeline (TPP), which enables an iterative workflow whereby fragment ion peaks explained by a peptide ion identified in one round of sequence searching or spectral library search are attenuated based on the confidence of the identification, and then the altered spectrum is subjected to further rounds of searching. The reSpect tool is not implemented as a search engine, but rather as a post-search engine processing step where only fragment ion intensities are altered. This enables the application of any search engine combination in the iterations that follow. Thus, reSpect is compatible with all other protein sequence database search engines as well as peptide spectral library search engines that are supported by the TPP. We show that while some datasets are highly amenable to chimeric spectrum identification and lead to additional peptide identification boosts of over 30% with as many as four different peptide ions identified per spectrum, datasets with narrow precursor ion selection only benefit from such processing at the level of a few percent. We demonstrate a technique that facilitates the determination of the degree to which a dataset would benefit from chimeric spectrum analysis. The reSpect tool is free and open source, provided within the TPP and available at the TPP website. Graphical Abstract ᅟ.

Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

Directory of Open Access Journals (Sweden)

N. C. Bouvier-Brown

2009-03-01

Full Text Available We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS, a proton transfer reaction mass spectrometer (PTR-MS, and a thermal desorption aerosol GC-MS (TAG – and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO, a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg⁻¹ h⁻¹, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

Ejection of Coulomb Crystals from a Linear Paul Ion Trap for Ion-Molecule Reaction Studies.

Science.gov (United States)

Meyer, K A E; Pollum, L L; Petralia, L S; Tauschinsky, A; Rennick, C J; Softley, T P; Heazlewood, B R

2015-12-17

Coulomb crystals are being increasingly employed as a highly localized source of cold ions for the study of ion-molecule chemical reactions. To extend the scope of reactions that can be studied in Coulomb crystals-from simple reactions involving laser-cooled atomic ions, to more complex systems where molecular reactants give rise to multiple product channels-sensitive product detection methodologies are required. The use of a digital ion trap (DIT) and a new damped cosine trap (DCT) are described, which facilitate the ejection of Coulomb-crystallized ions onto an external detector for the recording of time-of-flight (TOF) mass spectra. This enables the examination of reaction dynamics and kinetics between Coulomb-crystallized ions and neutral molecules: ionic products are typically cotrapped, thus ejecting the crystal onto an external detector reveals the masses, identities, and quantities of all ionic species at a selected point in the reaction. Two reaction systems are examined: the reaction of Ca(+) with deuterated isotopologues of water, and the charge exchange between cotrapped Xe(+) with deuterated isotopologues of ammonia. These reactions are examples of two distinct types of experiment, the first involving direct reaction of the laser-cooled ions, and the second involving reaction of sympathetically-cooled heavy ions to form a mixture of light product ions. Extensive simulations are conducted to interpret experimental results and calculate optimal operating parameters, facilitating a comparison between the DIT and DCT approaches. The simulations also demonstrate a correlation between crystal shape and image shape on the detector, suggesting a possible means for determining crystal geometry for nonfluorescing ions.

Moderate nutrient restriction influences transcript abundance of genes impacting production efficiencies of beef cattle in fetal liver, muscle, and cerebrum by d 50 of gestation

Science.gov (United States)

We hypothesized that a moderate maternal nutrient restriction during the first 50 d of gestation in beef heifers would affect transcript abundance of genes impacting production efficiency phenotypes in fetal liver, muscle, and cerebrum. Fourteen Angus-cross heifers were estrus synchronized and assig...

DIRECT EVALUATION OF THE HELIUM ABUNDANCES IN OMEGA CENTAURI

Energy Technology Data Exchange (ETDEWEB)

Dupree, A. K.; Avrett, E. H., E-mail: dupree@cfa.harvard.edu, E-mail: eavrett@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2013-08-20

A direct measure of the helium abundances from the near-infrared transition of He I at 1.08 {mu}m is obtained for two nearly identical red giant stars in the globular cluster Omega Centauri. One star exhibits the He I line; the line is weak or absent in the other star. Detailed non-local thermal equilibrium semi-empirical models including expansion in spherical geometry are developed to match the chromospheric H{alpha}, H{beta}, and Ca II K lines, in order to predict the helium profile and derive a helium abundance. The red giant spectra suggest a helium abundance of Y {<=} 0.22 (LEID 54064) and Y = 0.39-0.44 (LEID 54084) corresponding to a difference in the abundance {Delta}Y {>=} 0.17. Helium is enhanced in the giant star (LEID 54084) that also contains enhanced aluminum and magnesium. This direct evaluation of the helium abundances gives observational support to the theoretical conjecture that multiple populations harbor enhanced helium in addition to light elements that are products of high-temperature hydrogen burning. We demonstrate that the 1.08 {mu}m He I line can yield a helium abundance in cool stars when constraints on the semi-empirical chromospheric model are provided by other spectroscopic features.

Production of highly charged ions of argon by optical field ionization in a relativistic laser field

International Nuclear Information System (INIS)

Sagisaka, Akito; Akahane, Yutaka; Aoyama, Makoto; Nakano, Fumihiko; Yamakawa, Koichi

2001-01-01

We observed the highly charged ions of argon by optical field ionization in a relativistic intensity regime. Charge states up to Ar 15+ were produced at the highest intensity of 800 nm, linearly polarized 20 fs Ti: sapphire laser pulses. The peak intensity of the pulse is determined by comparing the measured ion production curve for Ar 9+ with ADK theory. The results of these measurements of the ionization indicate that the maximum peak intensity is achieved to ∼2x10 19 W/cm 2 . (author)

Some remarks on the statistical model of heavy ion collisions

International Nuclear Information System (INIS)

Koch, V.

2003-01-01

This contribution is an attempt to assess what can be learned from the remarkable success of this statistical model in describing ratios of particle abundances in ultra-relativistic heavy ion collisions

Calculations on Electron Capture in Low Energy Ion-Molecule Collisions

Energy Technology Data Exchange (ETDEWEB)

Stancil, P.C. [Oak Ridge National Lab., TN (United States); Zygelman, B. [W.M. Keck Lab. for Computational Physics, Univ. of Nevada, Las Vegas, NV (United States); Kirby, K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

1997-12-31

Recent progress on the application of a quantal, molecular-orbital, close-coupling approach to the calculation of electron capture in collisions of multiply charged ions with molecules is discussed. Preliminary results for single electron capture by N{sup 2+} with H{sub 2} are presented. Electron capture by multiply charged ions colliding with H{sub 2} is an important process in laboratory and astrophysical plasmas. It provides a recombination mechanism for multiply charged ions in x-ray ionized astronomical environments which may have sparse electron and atomic hydrogen abundances. In the divertor region of a tokamak fusion device, charge exchange of impurity ions with H{sub 2} plays a role in the ionization balance and the production of radiative energy loss leading to cooling, X-ray and ultraviolet auroral emission from Jupiter is believed to be due to charge exchange of O and S ions with H{sub 2} in the Jovian atmosphere. Solar wind ions interacting with cometary molecules may have produced the x-rays observed from Comet Hyakutake. In order to model and understand the behavior of these environments, it is necessary to obtain total, electronic state-selective (ESS), and vibrational (or rotational) state-selective (VSS) capture cross sections for collision energies as low as 10 meV/amu to as high as 100 keV/amu in some instances. Fortunately, charge transfer with molecular targets has received considerable experimental attention. Numerous measurements have been made with flow tubes, ion traps, and ion beams. Flow tube and ion trap studies generally provide information on rate coefficients for temperatures between 800 K and 20,000 K. In this article, we report on the progress of our group in implementing a quantum-mechanical Molecular Orbital Close Coupling (MOCC) approach to the study of electron capture by multiply charged ions in collisions with molecules. We illustrate this with a preliminary investigation of Single Electron Capture (SEC) by N{sup 2+} with H

Pair production with electron capture in peripheral collisions of relativistic heavy ions

Energy Technology Data Exchange (ETDEWEB)

Bertulani, C.A.C.A. E-mail: bertu@if.ufrj.br; Dolci, D.D. E-mail: dolci@if.ufrj.br

2001-02-26

The production of electron-positron pairs with the capture of the electron in an atomic orbital is investigated for the conditions of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). Dirac wave functions for the leptons are used, taking corrections to orders of Z{alpha} into account. The dependence on the transverse momentum transfer is studied and the accuracy of the equivalent photon approximation is discussed as a function of the nuclear charge.

Factors influencing the abundance of pests in production fields and rates of interception of Dracaena marginata imported from Costa Rica.

Science.gov (United States)

Hidalgo, Eduardo; Benjamin, Tamara; Casanoves, Fernando; Sadof, Clifford

2013-10-01

Importation of live nursery plants, like Dracaena marginata Lamoureux (Ruscaceae), can provide a significant pathway for the entry of foliar pests from overseas into the United States. We studied the abundance of foliar pests of quarantine importance found on Costa Rican-grown D. marginata. These include five genera of leafhoppers (Heteroptera: Cicadellidae, Oncometopia, Caldweliola, Diestostema, Cypona, and Empoasca), Florida red scale (Heteroptera: Disapididae, Chrysomphalus aoinidum (L.)), katydids (Orthoptera: Tettigoniidae), and a snail (Succinea costarricana von Martens (Gastropoda, Stylommatophora, Succineidae)). In our first study, we examined the rationale behind size restrictions on Dracaena cuttings imported into the United States from Costa Rica. When comparing plant size, no differences were found in the abundance of quarantined pests on small (15-46 cm), medium (46-81 cm), and large (81-152 cm) propagules. In a second study, we estimated monthly abundances of pests in production plots for 1 yr to determine their relationship to rates of interception at U.S. ports. In any given month, pest. There was no relationship between the average monthly frequencies of pest detection in the field and in U.S. inspection ports. Pest detections increased during the 1 mo when average monthly shipments were abnormally high. Our data suggest that off-shore postprocessing efforts to remove pest-infested material from the market stream need to be adjusted to accommodate sharp increases in the volume of shipped plants.

Effects of metal ions on biomass and 5-aminolevulinic acid production in Rhodopseudomonas palustris wastewater treatment.

Science.gov (United States)

Liu, Shuli; Zhang, Guangming; Li, Jianzheng; Li, Xiangkun; Zhang, Jie

2016-01-01

This work investigated the effects of eight metal ions on Rhodopseudomonas palustris growth and 5-aminolevulinic acid (ALA) yield in wastewater treatment. Results show that metal ions (Mg(2+) of 15 mmol/L, Fe(2+) of 400 μmol/L, Co(2+) of 4 μmol/L, Ni(2+) of 8 μmol/L and Zn(2+) of 4 μmol/L) could effectively improve the chemical oxygen demand (COD) removal, Rp. palustris biomass and ALA yield. The highest ALA yield of 13.1 mg/g-biomass was achieved with Fe(2+) of 400 μmol/L. ALA yields were differentially increased under different metal ions in the following order: Fe(2+) group > Mg(2+) group > Co(2+) group = Ni(2+) group > Zn(2+) group = Mo(2+) group > control. Cu(2+) and Mn(2+) inhibited Rp. palustris growth and ALA production. Mechanism analysis revealed that metal ions changed ALA yields by influencing the activities of ALA synthetase and ALA dehydratase.

Release of mineral ions in dental plaque following acid production.

Science.gov (United States)

Tanaka, M; Margolis, H C

1999-03-01

The release of appreciable amounts of calcium, phosphate and fluoride found in whole plaque into the plaque-fluid phase, following bacterial acid production, can potentially reduce the driving force for tooth demineralization. However, limited information is available on this topic, particularly on the release of fluoride. This study sought to determine the change in calcium, phosphate and fluoride concentrations in plaque fluid after sucrose exposure. 48 h overnight-fasted supragingival plaque samples were collected from all tooth surfaces (with the exception of the lower lingual anterior teeth) of one half of an individual mouth, following a 1 min water rinse. Plaque samples were then collected from the other half of the same mouth, following a 292 mM sucrose rinse. Plaque fluid was isolated by centrifugation and analysed for total calcium and phosphate (ion chromatography) and for free fluoride (ion-specific electrode). Samples were collected from seven individuals. Following sucrose exposure, plaque-fluid pH decreased significantly from 6.5+/- 0.3 to 5.4+/-0.2; calcium concentrations (mmol/l) also increased significantly (p Fluoride and phosphate concentrations in plaque fluid, however, did not increase significantly after sucrose exposure: mean concentrations (mmol/l) of fluoride after the water and sucrose rinses were 0.006+/-0.003 and 0.005+/-0.002, respectively, and mean phosphate concentrations (mmol/l) were 11.0+/-2.0 and 12.0+/-3.0, respectively. When results were expressed per wet plaque weight, phosphate concentrations were also found to increase significantly. The same trends were observed when additional plaque samples were treated in vitro with sucrose: fluoride-ion activity did not increase in plaque under in vivo-like conditions.

Cosmological evolution of the nitrogen abundance

Science.gov (United States)

Vangioni, Elisabeth; Dvorkin, Irina; Olive, Keith A.; Dubois, Yohan; Molaro, Paolo; Petitjean, Patrick; Silk, Joe; Kimm, Taysun

2018-06-01

The abundance of nitrogen in the interstellar medium is a powerful probe of star formation processes over cosmological time-scales. Since nitrogen can be produced both in massive and intermediate-mass stars with metallicity-dependent yields, its evolution is challenging to model, as evidenced by the differences between theoretical predictions and observations. In this work, we attempt to identify the sources of these discrepancies using a cosmic evolution model. To further complicate matters, there is considerable dispersion in the abundances from observations of damped Lyα absorbers (DLAs) at z ˜ 2-3. We study the evolution of nitrogen with a detailed cosmic chemical evolution model and find good agreement with these observations, including the relative abundances of (N/O) and (N/Si). We find that the principal contribution of nitrogen comes from intermediate-mass stars, with the exception of systems with the lowest N/H, where nitrogen production might possibly be dominated by massive stars. This last result could be strengthened if stellar rotation which is important at low metallicity can produce significant amounts of nitrogen. Moreover, these systems likely reside in host galaxies with stellar masses below 108.5 M⊙. We also study the origin of the observed dispersion in nitrogen abundances using the cosmological hydrodynamical simulations Horizon-AGN. We conclude that this dispersion can originate from two effects: difference in the masses of the DLA host galaxies, and difference in their position inside the galaxy.

Research progress in intense ion beam production for inertial confinement fusion at Cornell University

International Nuclear Information System (INIS)

Bluhm, H.; Greenly, J.B.; Hammer, D.A.

1983-01-01

Recent results obtained in the generation of intense pulsed light ion beams and their application to inertial confinement fusion are described. Studies of time-integrated and time-dependent beam divergence using a magnetically insulated ion diode with a ''flashboard'' anode at 11 W diode power show a directionality which is apparently due to electron dynamics in the diode. Nevertheless, ion beams having divergence angle as small as 0.5 0 have been produced at >10 8 W.cm - 2 . In another experiment with a similar diode, the anode plasma formation time varied with the detailed anode configuration, the diode voltage and the insulating magnetic field, with the longer times obtained at lower voltage and higher insulating magnetic field strength. The anode plasma density was determined to be in the 10 15 cm - 3 density range and to move away from the anode at approx.2 cm.μs - 1 in another similar experiment. Preliminary experiments performed on a 10 12 W accelerator show reasonable power coupling to a magnetically insulated ion diode, with >10 9 W.cm - 2 beams at approx.1.5 MV being generated. Computer simulations suggest that if such a beam can be focused into a plasma channel, most of its energy can be delivered to a pellet one to two metres away. In experiments on the applied Bsub(theta) diode, microwave radiation, ion production efficiency, and ion beam fluctuations all reach a maximum when the insulating magnetic field is about 1.4 times the critical field for magnetic insulation. Finally, relatively pure beams of heavy ions have been produced by making the anode with hydrocarbon-free dielectric material which contains the desired species together with other ions having substantially higher ionization potential. The sum of these results suggests that flashboard anodes operated at the few-MV level can be used to produce beams with properties suitable for inertial confinement fusion experiments on sufficiently powerful pulsed power generators. (author)

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

International Nuclear Information System (INIS)

Shukla, Anil; Bogdanov, Bogdan

2015-01-01

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

Optical effects of ion implantation

International Nuclear Information System (INIS)

Townsend, P.D.

1987-01-01

The review concerns the effects of ion implantation that specifically relate to the optical properties of insulators. Topics which are reviewed include: ion implantation, ion range and damage distributions, colour centre production by ion implantation, high dose ion implantation, and applications for integrated optics. Numerous examples are presented of both diagnostic and industrial examples of ion implantation effects in insulators. (U.K.)

The production and destruction of negative ions. Progress report, September 1, 1996 - August 31, 1997

International Nuclear Information System (INIS)

Pegg, D.J.

1997-01-01

During the grant period, 1994--97, the author continued to investigate the structure of few-electron atomic negative ions and the manner in which they interact with electromagnetic radiation. The experimental procedures and the results of this work have been described in detail in the published papers cited in Section G. Two complementary laser-ion beam apparatus were used in the measurements. A crossed beam apparatus, situated at Oak Ridge National Laboratory (ORNL), was used to perform a spectroscopic study of the electrons ejected, in the forward direction, from moving negative ions in the photodetachment process. In this work, the author isolated specific detachment channels by energy analyzing the electrons. The apparatus was used to investigate photodetachment of an electron from a negative ion in an excited state. The C - ion is unusual in that it can be produced in a bound excited state as well as the ground state. The author also used this apparatus, with ba gaseous target replacing the laser beam, to study resonances in collisional detachment cross sections. In particular, he investigated the simplest of all shape resonances, the 3 P O state in Li - . This state was produced in Li - -He collisions. A collinear beam apparatus, situated at Chalmers University of Technology (CUT) in Gothenburg, Sweden, has been used in spectroscopic studies of the He - and Li - ion in the ultraviolet. Here, the emphasis is on the production and detection of highly correlated, doubly excited states

Mass Spectrum Analysis of CO2 and N2 Using Ion Beam Separator System

International Nuclear Information System (INIS)

Tjipto-Sujitno, BA; Darsono; Agus-Santoso

2000-01-01

The main purpose of this research is to study investigate the massspectrum profile of CO 2 and N 2 emitted from Penning ion source using ionbeam separator. Besides that, it is also identified the compositions of CO 2 and N 2 ion gas and their abundances through their mass spectrum profile,because as we know that these ions are consist of ion of atom or molecule aswell as the their abundances. To get these profiles, the ion beam acceleratedin accelerating tube are passed through magnet separator. After passing themagnet separator, the ion current beam was detected using microampere meter.By scanning the strength of magnetic field, it will be found the currentspectrum profile as a function of magnetic field. From this current spectrum,we can make a mass spectrum profile. From experiment done, it was found thatthe mass spectrum peak of CO 2 and N 2 were C + with m/z = (12.00 ± 0.10)amu, O 2 + = (31.96 ± 0.29) amu, CO 2 + = (43.93 ± 0.31) amu, N + (13.97 ± 0.33) amu, and N 2 + = (28.05 ± 0.18) amu. (author)

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

International Nuclear Information System (INIS)

Beiersdorfer, P.

1994-01-01

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

Gas phase ion chemistry

CERN Document Server

Bowers, Michael T

1979-01-01

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

The Influence of Mg(II and Ca(II Ions on Rutin Autoxidation in Weakly Alkaline Aqueous Solutions

Directory of Open Access Journals (Sweden)

Živanović Slavoljub C.

2016-09-01

Full Text Available Rutin (quercetin-3-O-rutinoside is one of the most abundant bioflavonoids with various biological and pharmacological activities. Considering the ubiquitous presence of Mg(II and Ca(II ions in biological systems we decided to investigate their influence on the autoxidation of rutin in weakly alkaline aqueous solutions. Changes in UV-Vis spectra recorded during the rutin autoxidation in aqueous solution at pH 8.4 revealed that this process was very slow in the absence of metal ions. The presence of Mg(II and, especially Ca(II ion, increased the transformation rate of rutin. UV-Vis spectra recorded after prolonged autoxidation indicated the formation of humic acidlike products in the presence of Mg(II and Ca(II ions. Four new compounds formed during the initial stage of rutin autoxidation in the presence of Mg(II and Ca(II ions were detected by HPLCDAD. Based on the analysis of their DAD UV-Vis spectra and comparison of their retention times with the retention time value for rutin, we concluded that the initial rutin transformation products were formed by the water addition on double bond in ring C and hydroxylation of ring B. A very small decrease of the initial rutin concentration (4% was observed by HPLC-DAD in the absence of metal ions for the period of 90 minutes. However, rutin concentration decrease was much larger in the presence of Mg(II and Ca(II ions (14% and 24%, respectively. The more pronounced effect of Ca(II ion on the rutin autoxidation may be explained by the stronger binding of Mg(II ion to rutin and thus greater stabilizing effect on reaction intermediates caused by its higher ionic potential (charge/ionic radius ratio in comparison to Ca(II ion. The results of this study may contribute to the better understanding of interactions of Mg(II and Ca(II ions with natural phenolic antioxidants which are important for their various biological activities.

Production of intensive negative lithium beam with caesium sputter-type ion source

Science.gov (United States)

Lobanov, Nikolai R.

2018-01-01

Compounds of lithium oxide, hydroxide and carbonate, mixed with silver, were prepared for use as a cathode in caesium-sputter ion source. The intention was to determine the procedure which would produce the highest intensity negative lithium beams over extended period and with maximum stability. The chemical composition and properties of the samples were analysed using mass-spectrometry, optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analyses (EDX) and Raman spectroscopy. These analyses showed that the chemical transformations with components resulted from pressing, storage and bake out were qualitatively in agreement with expectations. Intensive negative lithium ion beams >1 μA were delivered using cathodes fabricated from materials with multicomponent chemical composition when the following conditions were met: (i) use of components with moderate enthalpy of formation; (ii) low moisture content at final stage of cathode production and (iii) small concentration of water molecules in hydrate phase in the cathode mixture.

Abundances of presolar silicon carbide grains in primitive meteorites determined by NanoSIMS

Science.gov (United States)

Davidson, Jemma; Busemann, Henner; Nittler, Larry R.; Alexander, Conel M. O.'D.; Orthous-Daunay, François-Régis; Franchi, Ian A.; Hoppe, Peter

2014-08-01

It has been suggested that the matrices of all chondrites are dominated by a common material with Ivuna-like (CI) abundances of volatiles, presolar grains and insoluble organic matter (IOM) (e.g., Alexander, 2005). However, matrix-normalized abundances of presolar silicon carbide (SiC) grains estimated from their noble gas components show significant variations in even the most primitive chondrites (Huss and Lewis, 1995; Huss et al., 2003), in contradiction to there being a common chondrite matrix material. Here we report presolar SiC abundances determined by NanoSIMS raster ion imaging of IOM extracted from primitive members of different meteorite groups. We show that presolar SiC abundance determinations are comparable between NanoSIMS instruments located at three different institutes, between residues prepared by different demineralization techniques, and between microtomed and non-microtomed samples. Our derived SiC abundances in CR chondrites are comparable to those found in the CI chondrites (∼30 ppm) and are much higher than previously determined by noble gas analyses. The revised higher CR SiC abundances are consistent with the CRs being amongst the most primitive chondrites in terms of the isotopic compositions and disordered nature of their organic matter. Similar abundances between CR1, CR2, and CR3 chondrites indicate aqueous alteration on the CR chondrite parent body has not progressively destroyed SiC grains in them. A low SiC abundance for the reduced CV3 RBT 04133 can be explained by parent body thermal metamorphism at an estimated temperature of ∼440 °C. Minor differences between primitive members of other meteorite classes, which did not experience such high temperatures, may be explained by prolonged oxidation at lower temperatures under which SiC grains formed outer layers of SiO2 that were not thermodynamically stable, leading to progressive degassing/destruction of SiC.

Production of spectator hypermatter in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Botvina, A. S.; Gudima, K. K.; Steinheimer, J.; Bleicher, M.; Mishustin, I. N.

2011-01-01

Possible formation of large hyperfragments in relativistic heavy-ion collisions is studied within two transport models, the Dubna cascade model and UrQMD model. Our goal is to explore a new mechanism for the formation of strange nuclear systems via capture of hyperons by relatively cold spectator matter produced in semiperipheral collisions. We investigate basic characteristics of the produced hyperspectators and estimate the production probabilities of multistrange systems. Advantages of the proposed mechanisms over an alternative coalescence process are analyzed. We also discuss how such hyperfragments can be detected by taking into account the background of free hyperons. This investigation is important for the development of new experimental methods for producing hypernuclei in peripheral relativistic nucleus-nucleus collisions, which are now underway at GSI and are planned for the future FAIR and NICA facilities.

Thin film analysis by instrumental heavy ion activation analysis using distributed recoil ranges of isotopic products

International Nuclear Information System (INIS)

Chowdhury, D.P.; Guin, R.; Saha, S.K.; Sudersanan, M.

2006-01-01

Thin foils (0.1 to 10 μm), metallic or polymeric, are frequently used in nuclear physics and chemistry experiments using ion beams from an accelerator. Very often it is important to know the major, minor and trace element composition of the foil. Several nuclear analytical techniques, namely RBS, ERDA, etc. are available for the near surface analysis. We have applied heavy ion activation analysis (HIAA) to explore the bulk composition of thin films. One of the difficulties in this method of thin film analysis is that the product nuclides from nuclear reaction come out of the sample surface due to high recoil energy. In thick sample, the recoiled nuclides are absorbed in the sample itself. This effect has been used to employ heavy ion activation for the analysis of thin films

Upgrade of the facility EXOTIC for the in-flight production of light Radioactive Ion Beams

Energy Technology Data Exchange (ETDEWEB)

Mazzocco, M., E-mail: marco.mazzocco@pd.infn.it [Dipartimento di Fisica e Astronomia, Universitá di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); INFN-Sezione di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Torresi, D.; Strano, E. [Dipartimento di Fisica e Astronomia, Universitá di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); INFN-Sezione di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Boiano, A. [INFN-Sezione di Napoli, Via Cinthia, I-80126 Napoli (Italy); Boiano, C. [INFN-Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Costa, L. [INFN-LNL, Viale dell’Università 2, I-35020 Legnaro, PD (Italy); Glodariu, T. [NIPNE, 407 Atomistilor Street, 077125 Magurele (Romania); Guglielmetti, A. [INFN-Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Dipartimento di Fisica,Università di Milano, Via Celoria 16, I-20133 Milano (Italy); La Commara, M. [INFN-Sezione di Napoli, Via Cinthia, I-80126 Napoli (Italy); Dipartimento di Scienze Fisiche, Università di Napoli, Via Cinthia, I-80126 Napoli (Italy); Parascandolo, C. [Dipartimento di Fisica e Astronomia, Universitá di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); INFN-Sezione di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Pierroutsakou, D. [INFN-Sezione di Napoli, Via Cinthia, I-80126 Napoli (Italy); Signorini, C.; Soramel, F. [Dipartimento di Fisica e Astronomia, Universitá di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); INFN-Sezione di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Stroe, L. [NIPNE, 407 Atomistilor Street, 077125 Magurele (Romania)

2013-12-15

Highlights: • Production of in-flight Radioactive Ion Beams via two-body reactions. • Development of a cryogenic gas target. • Event-by-event tracking via Parallel Plate Avalanche Counters (PPACs). -- Abstract: The facility EXOTIC for the in-flight production of light weakly-bound Radioactive Ion Beams (RIBs) has been operating at INFN-LNL since 2004. RIBs are produced via two-body reactions induced by high intensity heavy-ion beams impinging on light gas targets and selected by means of a 30°-dipole bending magnet and a 1-m long Wien filter. The facility has been recently upgraded (i) by developing a cryogenic gas target, (ii) by replacing the power supplies of the middle lenses of the two quadrupole triplets, (iii) by installing two y-steerers and (iv) by placing two Parallel Plate Avalanche Counters upstream the secondary target to provide an event-by-event reconstruction of the position hit on the target. So far, RIBs of {sup 7}Be, {sup 8}B and {sup 17}F in the energy range 3–5 MeV/u have been produced with intensities about 3 × 10{sup 5}, 1.6 × 10{sup 3} and 10{sup 5} pps, respectively. Possible light RIBs (up to Z = 10) deliverable by the facility EXOTIC are also reviewed.

USE OF SILVER IONS IN PASTEURIZED MILK PRODUCTION

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A. Mamaev

2012-10-01

Full Text Available The means of pasteurized milk shelf life prolongation by electro-chemical diffusion of silver ions has been introduced. Three samples of pasteurized milk were test subjects. In the course of study the following data have been examined: organoleptic, physicochemical, microbiological parameters of check samples and pilot samples of raw and pasteurized milk. Its shelf life has been determined. It has been determined that the test results of raw and pasteurized milk samples processed by various concentration of silver ions showed minor difference in organoleptic, physic-chemical, microbiological parameters and shelf life span. In this connection it appears reasonable to use the smallest concentration of silver ions - 50 micrograms per liter for milk shelf life prolongation as it is considered the least harmful for person's organism. Infusion of silver ions in the concentration of 50 micrograms per liter allows to prolong raw and pasteurized milk shelf life by two days.