Negative ion beam extraction in ROBIN

International Nuclear Information System (INIS)

Bansal, Gourab; Gahlaut, Agrajit; Soni, Jignesh; Pandya, Kaushal; Parmar, Kanu G.; Pandey, Ravi; Vuppugalla, Mahesh; Prajapati, Bhavesh; Patel, Amee; Mistery, Hiren; Chakraborty, Arun; Bandyopadhyay, Mainak; Singh, Mahendrajit J.; Phukan, Arindam; Yadav, Ratnakar K.; Parmar, Deepak

2013-01-01

Highlights: ► A RF based negative hydrogen ion beam test bed has been set up at IPR, India. ► Ion source has been successfully commissioned and three campaigns of plasma production have been carried out. ► Extraction system (35 kV) has been installed and commissioning has been initiated. Negative ion beam extraction is immediate milestone. -- Abstract: The RF based single driver −ve ion source experiment test bed ROBIN (Replica Of BATMAN like source in INDIA) has been set up at Institute for Plasma Research (IPR), India in a technical collaboration with IPP, Garching, Germany. A hydrogen plasma of density 5 × 10 12 cm −3 is expected in driver region of ROBIN by launching 100 kW RF power into the driver by 1 MHz RF generator. The cesiated source is expected to deliver a hydrogen negative ion beam of 10 A at 35 kV with a current density of 35 mA/cm 2 as observed in BATMAN. In first phase operation of the ROBIN ion source, a hydrogen plasma has been successfully generated (without extraction system) by coupling 80 kW RF input power through a matching network with high power factor (cos θ > 0.8) and different plasma parameters have been measured using Langmuir probes and emission spectroscopy. The plasma density of 2.5 × 10 11 cm −3 has been measured in the extraction region of ROBIN. For negative hydrogen ion beam extraction in second phase operation, extraction system has been assembled and installed with ion source on the vacuum vessel. The source shall be first operated in volume mode for negative ion beam extraction. The commissioning of the source with high voltage power supply has been initiated

Profiles of fast ions that are accelerated by high harmonic fast waves in the National Spherical Torus Experiment

International Nuclear Information System (INIS)

Liu, D; Heidbrink, W W; Podesta, M; Ruskov, E; Bell, R E; Fredrickson, E D; Medley, S S; Harvey, R W

2010-01-01

Combined neutral beam injection and high-harmonic fast-wave (HHFW) heating accelerate deuterium fast ions in the National Spherical Torus Experiment (NSTX). With 1.1 MW of HHFW power, the neutron emission rate is about three times larger than in the comparison discharge without HHFW heating. Acceleration of fast ions above the beam injection energy is evident on an E||B type neutral particle analyzer (NPA), a 4-chord solid state neutral particle analyzer (SSNPA) array and a 16-channel fast-ion D-alpha (FIDA) diagnostic. The accelerated fast ions observed by the NPA and SSNPA diagnostics mainly come from passive charge exchange reactions at the edge due to the NPA/SSNPA localization in phase space. The spatial profile of accelerated fast ions that is measured by the FIDA diagnostic is much broader than in conventional tokamaks because of the multiple resonance layers and large orbits in NSTX. The fast-ion distribution function calculated by the CQL3D Fokker-Planck code differs from the measured spatial profile, presumably because the current version of CQL3D uses a zero-banana-width model. In addition, compressional Alfven eigenmode activity is stronger during the HHFW heating and it may affect the fast-ion spatial profile.

Studies of fast-ion transport induced by energetic particle modes using fast-particle diagnostics with high time resolution in CHS

International Nuclear Information System (INIS)

Isobe, M.; Toi, K.; Suzuki, C.; Nagaoka, K.; Matsushita, H.; Goto, K.

2006-01-01

The purpose of this work is to reveal the effects of the energetic particle mode (EPM) on fast-ion transport and consequent fast-ion loss in the Compact Helical System (CHS). For this purpose, fast particle diagnostics capable of following fast events originating from the EPM (f -5 Tesla at the magnetic probe position. The lost fast-ion probe (LIP) located at the outboard side of the torus indicates that bursting EPMs lead to periodically enhanced losses of co-going fast ions having smaller pitch angles in addition to losses of marginally co-passing fast ions. Coinciding with EPM bursts, the H- light detector viewing the peripheral region at the outboard side also shows large pulsed increases similar to that of the LIP whereas the detector viewing the peripheral region at the inboard side does not. This is also evidence that fast ions are expelled to the outboard side due to the EPM. The charge-exchange neutral particle analyzer indicates that only fast ions whose energy is close to the beam injection energy E b are strongly affected by EPM, suggesting in turn that observed EPMs are excited by fast ions having energy close to E b . (author)

Ion extraction in the cyclotron geometry

International Nuclear Information System (INIS)

Rodenburg, R.E.

1985-01-01

The detailed physics of ion beam extraction from a plasma column by intense sinusoidal radio frequency (rf) electric fields at the ion cyclotron frequency omega/sub ci/ and its harmonics is experimentally studied. Results describe the instantaneous relationship - within one rf period of approx. = 3009 nsec - between applied rf, the plasma response and the ions expelled by rf and plasma fields. Reflex discharges in H 2 , D 2 , and He with ion and electron densities greater than or equal to10 11 cm -3 are subjected to 0-5 kV zero-to-peak rf electric fields E vector and 0.65-9.00 kG background magnetic fields B 0 vector with E vector perpendicular to B 0 vector. Ion currents up to 200 μA are extracted. Nonperturbing optical diagnostics measure the relative amplitude and phase of instantaneous ion and electron density fluctuations induced by the rf during each rf cycle and the time variation of extracted ion bursts, the latter made possible by the use of a phosphor beam-stop. Detailed dependences on external electric and magnetic fields are reported. The plasma density fluctuations are in good agreement with the dispersion relation for electrostatic ion cyclotron waves (EICW), and the beam data show current enhancement at the second harmonic over that at the fundamental and evidence for a radically different mechanism for the rf-driven ion extraction process than conventional wisdom assumes. This work represents the first detailed, systematic study of the ac ion extraction process

Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR

International Nuclear Information System (INIS)

Delabie, E.; Jaspers, R. J. E.; Hellermann, M. G. von; Nielsen, S. K.; Marchuk, O.

2008-01-01

An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for active spectroscopy, injected counter the direction in which fast ions injected by the first beam are circulating, we can simultaneously measure a fast ion tail on the blue wing of the D α spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two parts of the spectrum offers possibilities to improve the accuracy of the absolute (fast) ion density profiles. Fast beam modulation or passive viewing lines cannot be used for background subtraction on this diagnostic setup and therefore the background has to be modeled and fitted to the data together with a spectral model for the slowing down feature. The analysis of the fast ion D α spectrum obtained with the new diagnostic is discussed.

Enhanced loss of fast ions during mode conversion ion Bernstein wave heating in TFTR

International Nuclear Information System (INIS)

Darrow, D.S.; Majeski, R.; Fisch, N.J.; Heeter, R.F.; Herrmann, H.W.; Herrmann, M.C.; Zarnstorff, M.C.; Zweben, S.J.

1995-12-01

A strong interaction of fast ions with ion Bernstein waves has been observed in TFTR. It results in a large increase in the fast ion loss rate, and heats the lost particles to several MeV. The lost ions are observed at the passing/trapped boundary and appear to be either DD fusion produced tritons or accelerated D neutral beam ions. Under some conditions, enhanced loss of DT alpha particles is also seen. The losses provide experimental support for some of the elements required for alpha energy channeling

Fast-ion transport studies using FIDA spectroscopy at the ASDEX Upgrade tokamak

International Nuclear Information System (INIS)

Geiger, Benedikt

2013-01-01

A good confinement of fast-ions, i.e. ions with energies above the thermal energy, is essential for the success of fusion devices as it determines, amongst others, the plasma performance and the heating and current drive efficiencies. In case of a turbulent or magneto-hydrodynamic (MHD) active background plasma, various mechanisms have to be considered in order to estimate the spatial distribution of the fast-ions: the slowing down and radial diffusion by Coulomb collisions on electrons and ions, the effect of potential fluctuations and the effect of perturbations of the magnetic field structure. These can lead to a broadening of the fast-ion distribution function which is not yet completely understood. At the fusion experiment ASDEX Upgrade, the fast-ions are generated by heating sources such as neutral beam injection (NBI). Their transport properties can be studied by a fast-ion D-alpha (FIDA) spectroscopy diagnostic which has been built in the framework of this thesis. Through charge exchange reactions with neutrals, fast-ions can receive a bound electron and emit Balmer alpha line radiation. This so-called FIDA radiation can be measured with large Doppler shifts and is localized along the NBI path where a high density of neutrals is present. The FIDA diagnostic uses radially distributed lines of sight that intersect, in the horizontal and in the vertical plane, the path of a 2.5 MW NBI heating source. Thereby different parts of the fast-ion phase space above 25 keV can be analyzed. To interpret the FIDA radiation quantitatively, a forward modelling code has been implemented, tested and further developed. The code calculates, based on theoretical fast-ion distribution functions, synthetic FIDA spectra that can be compared to the measurement. In MHD-quiescent plasmas, the possible effect of turbulence on the fast-ion transport has been investigated with the FIDA diagnostic. The measurements obtained under different experimental conditions, such as during on- and

Combination of fast-ion diagnostics in velocity-space tomographies

DEFF Research Database (Denmark)

Salewski, Mirko; Geiger, B.; Nielsen, Stefan Kragh

2013-01-01

Fast-ion Dα (FIDA) and collective Thomson scattering (CTS) diagnostics provide indirect measurements of fast-ion velocity distribution functions in magnetically confined plasmas. Here we present the first prescription for velocity-space tomographic inversion of CTS and FIDA measurements that can ...

High-definition velocity-space tomography of fast-ion dynamics

DEFF Research Database (Denmark)

Salewski, Mirko; Geiger, B.; Jacobsen, A.S.

2016-01-01

Velocity-space tomography of the fast-ion distribution function in a fusion plasma is usually a photon-starved tomography method due to limited optical access and signal-to-noise ratio of fast-ion Dα (FIDA) spectroscopy as well as the strive for high-resolution images. In high-definition tomography...... information to reconstruct where in velocity space the measurements and the simulation disagree. This alternative approach is demonstrated for four-view as well as for two-view FIDA measurements. The high-definition tomography tools allow us to study fast ions in sawtoothing plasmas and the formation of NBI...

Fast-ion transport and neutral beam current drive in ASDEX upgrade

DEFF Research Database (Denmark)

Geiger, B.; Weiland, M.; Jacobsen, Asger Schou

2015-01-01

The neutral beam current drive efficiency has been investigated in the ASDEX Upgrade tokamak by replacing on-axis neutral beams with tangential off-axis beams. A clear modification of the radial fast-ion profiles is observed with a fast-ion D-alpha diagnostic that measures centrally peaked profiles...... during on-axis injection and outwards shifted profiles during off-axis injection. Due to this change of the fast-ion population, a clear modification of the plasma current profile is predicted but not observed by a motional Stark effect diagnostic. The fast-ion transport caused by MHD activity has been...

Simulation study on ion extraction from ECR ion sources

International Nuclear Information System (INIS)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author)

Simulation study on ion extraction from ECR ion sources

Energy Technology Data Exchange (ETDEWEB)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author).

Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

International Nuclear Information System (INIS)

GarcIa-Munoz, M.; Hicks, N.; Classen, I.G.J.; Bilato, R.; Bobkov, V.; Brambilla, M.; Bruedgam, M.; Fahrbach, H.-U.; Igochine, V.; Maraschek, M.; Sassenberg, K.; Van Voornveld, R.; Jaemsae, S.

2010-01-01

The phase-space of convective and diffusive fast-ion losses induced by shear Alfven eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfven eigenmodes (TAEs) and Alfven cascades (ACs) have allowed to identify both loss mechanisms. While single ACs and TAEs eject resonant fast-ions in a convective process, the overlapping of AC and TAE spatial structures leads to a large fast-ion diffusion and loss. The threshold for diffusive fast-ion losses depends on the ion energy (gyroradius). Diffusive fast-ion losses with gyroradius ∼70 mm have been observed with a single TAE for local radial displacements of the magnetic field lines larger than ∼2 mm. Multiple frequency chirping ACs cause an enhancement of the diffusive losses. The ACs and TAEs radial structures have been reconstructed by means of cross-correlation techniques between the fast-ion loss detector and the electron cyclotron emission radiometer.

Measurements of fast ion spatial dynamics during magnetic activity in the RFP

Science.gov (United States)

Goetz, J. A.; Anderson, J. K.; Bonofiglo, P.; Kim, J.; McConnell, R.; Magee, R. M.

2017-10-01

Fast ions in the RFP are only weakly affected by a stochastic magnetic field and behave nearly classically in concentration too low to excite Alfvenic activity. At high fast ion concentration sourced by H-NBI in 300kA RFP discharges, a substantial drop in core-localized high pitch fast ions is observed during bursts of coupled EPM and IAE (magnetic island-induced Alfven eigenmode) activity (100-200kHz) through neutral particle analysis. Sourcing instead fast deuterium with NBI, the DD fusion products can measure the dynamics of the fast ion density profile. Both a collimated neutron detector and a new 3MeV fusion proton detector loaned by TriAlpha Energy measure the fast ion density profile with 5cm spatial resolution and 100 μs temporal resolution. In D-NBI, the bursting EPM is excited at slightly lower frequency and the IAE activity is nearly absent, likely due to an isotope effect and loss of wave-particle interaction. In these cases, neutral particle analysis shows little change in the core-localized high pitch fast ion content, and the fusion product profile indicates little change in the fast ion density profile, leaving unexplained the mechanism removing EPM drive. We measure a substantial redistribution of the fast ion profile due to strong lower-frequency ( 30kHz) MHD activity that accompanies the current profile relaxation in the RFP. Profile flattening is strongest in low bulk density discharges, which often occur with a total increase in global neutron flux from acceleration of the beam ions. Work supported by US DoE.

Fast ion absorption of lower hybrid power in JET

International Nuclear Information System (INIS)

Andrade, M.C.R.; Brusati, M.

1993-01-01

The first experimental evidence at JET on the interaction of fast minority ions with LH is reported. An increase of approximately 20% on the fast ion energy content was observed in the presence of LH, with an estimated LH absorbed power of approximately 20% for 2 MW of LH power and plasma densities of 2.0 to 2.4 x 10 19 m -3 with central temperatures γ ray and neutron rates also show that absorption of LH waves by the fast minority ions is taking place. FFT analysis confirms a better damping of the wave when the overlap between ICRH and LHCD is maximized. (author)

Wave–particle resonances and redistribution/losses of fast ions in tokamaks

International Nuclear Information System (INIS)

Nabais, F.; Borba, D.; Kiptily, V.G.; Pinches, S.D.; Sharapov, S.E.

2012-01-01

Enhanced fast ion losses, mostly in the range of energies from around 1.2 to 2.4 MeV, were measured during the activity of tornado modes in the JET tokamak. Tornado modes are TAE localized inside the q = 1 surface, which do not extend to the outer regions of the plasma. Thus, it is necessary to find an explanation on how such modes can lead to the loss of fast ions. In this paper, a mechanism that allows explaining the loss of fast ions triggered by tornado modes is proposed. This mechanism is based on the combined effect of tornado modes and global TAEs over the fast ions (global TAEs were always observed along with the tornado modes in the experiments in which enhanced losses were measured). Tornado modes would trigger the process of loss by resonantly interacting with the fast ions near the centre of the plasma and transporting the ions to a more peripheral region where tornado modes and global TAEs coexist. The TAE would then transport convectively the fast ions, most efficiently through the first bounce resonances (p = 1), all the way to the plasma edge eventually leading to its loss. This mechanism of loss is supported by calculations carried out with the CASTOR-K code. (paper)

Ionic Liquids as Extraction Media for Metal Ions

Science.gov (United States)

Hirayama, Naoki

In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

Fast Ion Redistribution and Implications for the Hybrid Regime

International Nuclear Information System (INIS)

Nazikian, R.; Austin, M.E.; Budny, R.V.; Chu, M.S.; Heidbrink, W.W.; Makowski, M.A.; Petty, C.C.; Politzer, P.A.; Solomon, W.M.; Van Zeeland, M.A.

2007-01-01

Time dependent TRANSP analysis indicates that radial redistribution of fast ions is unlikely to affect the central current density in hybrid plasmas sufficient to raise q(0) above unity. The results suggest that some other mechanism other than fast ion transport must be involved in raising q(0) and preventing sawteeth in hybrid plasmas.

Fast ion behavior during neutral beam injection in ATF

International Nuclear Information System (INIS)

Wade, M.R.; Thomas, C.E.; Colchin, R.J.; Rome, J.A.; England, A.C.; Fowler, R.H.; Aceto, S.C.

1993-01-01

In stellarators, single-particle confinement properties can be more complex than in their tokamak counterparts. Fast-ion behavior in tokamaks has been well characterized through an abundance of measurements on various devices and in general has been shown to be consistent with classical slowing-down theory, although anomalous ion behavior has been observed during intense beam injection in ISX-B, during fishbone instabilities in PDX, and in experiments on TFR. In contrast, fast ion behavior in stellarators is not as wel established experimentally with the primary experiments to date focusing o near-perpendicular or perpendicular neutral beam injection (NBI) on the Wendelstein 7-A stellarator (91 and Heliotron-E. This paper addresses fast-ion confinement properties in a large-aspect-ratio, moderate-shear stellarator, the Advanced Toroidal Facility, during tangential NBI. The primary data used in this study are the experimentally measured energy spectra of charge-exchange neutrals escaping from the plasma, using a two-dimensional scanning neutral particle analyzer. This diagnostic method is well established, having been used on several devices since the early 1970's. Various aspects of fast-ion behavior are investigated by comparing these data with computed theoretical spectra based on energeticion distributions derived from the fastion Fokker-Planck equation. Ion orbits are studied by computer orbit following, by the computation of J* surfaces, and by Monte Carlo calculations

Electron spectroscopy with fast heavy ions

International Nuclear Information System (INIS)

Schneider, D.

1983-01-01

Since about 1970 the spectroscopy of Auger-electrons and characteristic x-rays following energetic ion-atom collisions has received a great deal of attention. An increasing number of accelerators, capable of providing a large number of projectile ion species over a wide range of projectile energies, became available for studying ion-atom collision phenomena. Many charged particles from protons up to heavy ions like uranium can be accelerated to energies ranging over six orders of magnitude. This allows us to study systematically a great variety of effects accompanied by dynamic excitation processes of the atomic shells in either the projectile- or target-atoms. The studies yield fundamental information regarding the excitation mechanism (e.g., Coulomb and quasi-molecular excitation) and allow sensitive tests of atomic structure theories. This information in turn is valuable to other fields in physics like plasma-, astro-, or solid-state (surface) physics. It is a characteristic feature of fast heavy-ion accelerators that they can produce highly stripped ion species which have in turn the capability to highly ionize neutral target atoms or molecules in a single collision. The ionization process, mainly due to the strong electrical fields that are involved, allows us to study few-electron atoms with high atomic numbers Z. High resolution spectroscopy performed with these atoms allows a particularly good test of relativistic and QED effects. The probability of producing these few electron systems is determined by the charge state and the velocity of the projectile ions. In this contribution the possibilities of using electron spectroscopy as a tool to investigate fast ion-atom collisions is discussed and demonstrated with a few examples. 30 references

Ion beam heating for fast ignition

International Nuclear Information System (INIS)

Gus'kov, S.Yu.; Limpouch, J.; Klimo, O.

2010-01-01

Complete text of publication follows. The characteristics features of the formation of the spatial distribution of the energy transferred to the plasma from a beam of ions with different initial energies, masses and charges under fast ignition conditions are determined. The motion of the Bragg peak is extended with respect to the spatial distribution of the temperature of the ion-beam-heated medium. The parameters of the ion beams are determined to initiate different regimes of fast ignition of thermonuclear fuel precompressed to a density of 300-500 g/cm 3 - the edge regime, in which the ignition region is formed at the outer boundary of the fuel, and the internal regime, in which the ignition region is formed in central parts of the fuel. The conclusion on the requirements for fast ignition by light and heavy ion beams is presented. It is shown that the edge heating with negative temperature gradient is described by a self-similar solution. Such a temperature distribution is the reason of the fact that the ignited beam energy at the edge heating is larger than the minimal ignition energy by factor 1.65. The temperature Bragg peak may be produced by ion beam heating in the reactor scale targets with pR-parameter larger than 3-4 g/cm 2 . In particular, for central ignition of the targets with pR-parameters in the range of 4-8 g/cm 2 the ion beam energy should be, respectively, from 5 to 7 times larger than the minimal ignition energy. The work by S.Ye. Gus'kov, D.V. Il'in, and V.E. Sherman was supported by the Ministry of Education and Science of the Russian Federation under the program 'Development of the Scientific Potential of High Education for 2009-2010' (project no. 2.1.1/1505) and the Russian Foundation for Basic Research (project no. 08-02-01394 a ). The work by J. Limpouch and O. Klimo was supported by the Czech Ministry of Education (project no. LC528, MSM6840770022).

Longitudinal dynamics of laser-cooled fast ion beams

DEFF Research Database (Denmark)

Weidemüller, M.; Eike, B.; Eisenbarth, U.

1999-01-01

We present recent results of our experiments on laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. The longitudinal motion of the ions is directly cooled by the light pressure force, whereas efficient transverse cooling is obtained indirectly by longitudinal-transverse co......We present recent results of our experiments on laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. The longitudinal motion of the ions is directly cooled by the light pressure force, whereas efficient transverse cooling is obtained indirectly by longitudinal....... When applying laser cooling in square-well buckets over long time intervals, hard Coulomb collisions suddenly disappear and the longitudinal temperature drops by about a factor of three. The observed longitudinal behaviour of the beam shows strong resemblance with the transition to an Coulomb...

Quartz fast component opticallystimulated luminescence: Towards routine extraction for dating applications

International Nuclear Information System (INIS)

Shen, Zhixiong; Lang, Andreas

2016-01-01

Using an uncontaminated fast component is a key for improving the reliability of quartz OSL dating for many deposits. So far no approach to extract the fast component of quartz OSL has routinely been adopted for dating practice. Key challenges for extracting fast components are (1) the difficulty of finding a unique solution in curve-fitting deconvolution of OSL decay curves and (2) the relatively poor dating precision when using experimental fast component extraction. Here, a simple mathematic solution for fast component extraction is presented that is not relying on curve-fitting deconvolution and can easily be adopted into routine dating practices. By using specifically selected data points from smoothed OSL decay curves, the precision of equivalent doses calculated using the extracted fast component can be improved over equivalent doses calculated using bulk OSL. The fast component extraction is tested on a group of age-constrained samples containing both insufficiently bleached and sufficiently bleached deposits. Fast component OSL ages are as accurate as bulk OSL ages for the sufficiently bleached deposits, but more accurate for samples where bulk OSL is affected by insufficient bleaching. We also demonstrate how using a curve smoothing procedure can improve dating precision in case of both sufficiently and insufficiently bleached deposits. - Highlights: • A simple mathematical method to extract quartz OSL fast component is presented. • The method can be adopted in D_e calculation programs for routine extraction. • The method leads to an increase in accuracy and precision of D_e. • The method works for relatively dim samples with low signal-to-noise ratios.

Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

DEFF Research Database (Denmark)

Bindslev, H.; Nielsen, S.K.; Porte, L.

2006-01-01

Here we present the first measurements by collective Thomson scattering of the evolution of fast-ion populations in a magnetically confined fusion plasma. 150 kW and 110 Ghz radiation from a gyrotron were scattered in the TEXTOR tokamak plasma with energetic ions generated by neutral beam injection...... and ion cyclotron resonance heating. The temporal behavior of the spatially resolved fast-ion velocity distribution is inferred from the received scattered radiation. The fast-ion dynamics at sawteeth and the slowdown after switch off of auxiliary heating is resolved in time. The latter is shown...

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

International Nuclear Information System (INIS)

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

2005-01-01

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

Fast ion distribution in the presence of flow

Science.gov (United States)

Davidovits, Seth; Fisch, Nathaniel

2014-10-01

Experiments and simulations in multiple ICF related configurations have observed signs of bulk flow near stagnation. These configurations include both laser driven implosions such as at the NIF, as well as Z-Pinches. We investigate the possibilities for enhancement or depletion of fast ion tails in simplified flow models, with an eye towards applicability to ICF experiments. Small effects on the tail populations may substantially affect fusion output, as the fast ions in these tails have much larger fusion cross sections than thermal ions and make up the majority of fusion production for typical ICF temperatures. While in collisional plasma the bulk of the distribution function is driven toward Maxwellian in a few collision times, the high velocity tails can take much longer to form. Furthermore, the long mean free paths of the fast ions means they may sample differing regions of flow, while thermal particles only sample the local flow. This work was supported by DOE through Contracts DE-AC02-09CH1-1466 and 67350-9960 (Prime # DOE DE-NA0001836). Seth Davidovits would like to acknowledge support by the DOE-CSGF program under Grant DE-FG02-97ER25308.

Observation of fast-ion Doppler-shifted cyclotron resonance with shear Alfven waves

International Nuclear Information System (INIS)

Zhang Yang; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Vincena, S.; Carter, T. A.; Gekelman, W.; Leneman, D.; Pribyl, P.

2008-01-01

The Doppler-shifted cyclotron resonance (ω-k z v z =Ω f ) between fast ions and shear Alfven waves is experimentally investigated (ω, wave frequency; k z , axial wavenumber; v z , fast-ion axial speed; Ω f , fast-ion cyclotron frequency). A test particle beam of fast ions is launched by a Li + source in the helium plasma of the LArge Plasma Device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)], with shear Alfven waves (SAW) (amplitude δ B/B up to 1%) launched by a loop antenna. A collimated fast-ion energy analyzer measures the nonclassical spreading of the beam, which is proportional to the resonance with the wave. A resonance spectrum is observed by launching SAWs at 0.3-0.8ω ci . Both the magnitude and frequency dependence of the beam-spreading are in agreement with the theoretical prediction using a Monte Carlo Lorentz code that launches fast ions with an initial spread in real/velocity space and random phases relative to the wave. Measured wave magnetic field data are used in the simulation.

'Beam-emission spectroscopy' diagnostics also measure edge fast-ion light

International Nuclear Information System (INIS)

Heidbrink, W W; Bortolon, A; McKee, G R; Smith, D R

2011-01-01

Beam-emission spectroscopy (BES) diagnostics normally detect fluctuations in the light emitted by an injected neutral beam. Under some circumstances, however, light from fast ions that charge exchange in the high neutral-density region at the edge of the plasma make appreciable contributions to the BES signals. This 'passive' fast-ion D α (FIDA) light appears in BES signals from both the DIII-D tokamak and the National Spherical Torus Experiment (NSTX). One type of passive FIDA light is associated with classical orbits that traverse the edge. Another type is caused by instabilities that expel fast ions from the core; this light can complicate measurement of the instability eigenfunction.

Cyclotrons with fast variable and/or multiple energy extraction

Directory of Open Access Journals (Sweden)

C. Baumgarten

2013-10-01

Full Text Available We discuss the possibility in principle of stripping extraction in combination with reverse bends in isochronous separate-sector cyclotrons (and/or fixed field alternating gradient accelerators. If one uses reverse bends between the sectors (instead of or in combination with drifts and places stripper foils at the sector exit edges, the stripped beam has a reduced bending radius and it should be able to leave the cyclotron within the range of the valley—even if the beam is stripped at less than full energy. We are especially interested in stripping of H_{2}^{+}, as it doubles the charge to mass ratio of the ions. However the method could be applied to other ions or ionized molecules as well. For the production of proton beams by stripping extraction of an H_{2}^{+} beam, we discuss possible designs for three types of machines: First, a low-energy cyclotron for the simultaneous production of several beams at multiple energies—for instance 15, 30, and 70 MeV—thus allowing beam delivery on several isotope production targets. In this case it can be an advantage to have a strong energy dependence of the direction of the extracted beam. Second, we consider a fast variable-energy proton machine for cancer therapy that should allow extraction (of the complete beam at all energies in the range of about 70 MeV to about 250 MeV into the same beam line. Third, we consider a high-intensity high-energy machine, where the main design goals are extraction with low losses, low activation of components, and high reliability. Especially if such a machine is considered for an accelerator driven system (ADS, this extraction mechanism has advantages: Beam trips by the failure of electrostatic elements could be avoided and the turn separation would be less critical, which allows operation at lower main cavity voltages. This would in turn reduce the number of rf trips. The price that has to be paid for these advantages is an increase in size and/or field

Integrated tokamak modelling with the fast-ion Fokker–Planck solver adapted for transient analyses

International Nuclear Information System (INIS)

Toma, M; Hamamatsu, K; Hayashi, N; Honda, M; Ide, S

2015-01-01

Integrated tokamak modelling that enables the simulation of an entire discharge period is indispensable for designing advanced tokamak plasmas. For this purpose, we extend the integrated code TOPICS to make it more suitable for transient analyses in the fast-ion part. The fast-ion Fokker–Planck solver is integrated into TOPICS at the same level as the bulk transport solver so that the time evolutions of the fast ion and the bulk plasma are consistent with each other as well as with the equilibrium magnetic field. The fast-ion solver simultaneously handles neutral beam-injected ions and alpha particles. Parallelisation of the fast-ion solver in addition to its computational lightness owing to a dimensional reduction in the phase space enables transient analyses for long periods in the order of tens of seconds. The fast-ion Fokker–Planck calculation is compared and confirmed to be in good agreement with an orbit following a Monte Carlo calculation. The integrated code is applied to ramp-up simulations for JT-60SA and ITER to confirm its capability and effectiveness in transient analyses. In the integrated simulations, the coupled evolution of the fast ions, plasma profiles, and equilibrium magnetic fields are presented. In addition, the electric acceleration effect on fast ions is shown and discussed. (paper)

Calculation of the fast ion tail distribution for a spherically symmetric hot spot

Science.gov (United States)

McDevitt, C. J.; Tang, X.-Z.; Guo, Z.; Berk, H. L.

2014-10-01

The fast ion tail for a spherically symmetric hot spot is computed via the solution of a simplified Fokker-Planck collision operator. Emphasis is placed on describing the energy scaling of the fast ion distribution function in the hot spot as well as the surrounding cold plasma throughout a broad range of collisionalities and temperatures. It is found that while the fast ion tail inside the hot spot is significantly depleted, leading to a reduction of the fusion yield in this region, a surplus of fast ions is observed in the neighboring cold plasma region. The presence of this surplus of fast ions in the neighboring cold region is shown to result in a partial recovery of the fusion yield lost in the hot spot.

Calculation of the fast ion tail distribution for a spherically symmetric hot spot

Energy Technology Data Exchange (ETDEWEB)

McDevitt, C. J.; Tang, X.-Z.; Guo, Z. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Berk, H. L. [Department of Physics, University of Texas, Austin, Texas 78712 (United States)

2014-10-15

The fast ion tail for a spherically symmetric hot spot is computed via the solution of a simplified Fokker-Planck collision operator. Emphasis is placed on describing the energy scaling of the fast ion distribution function in the hot spot as well as the surrounding cold plasma throughout a broad range of collisionalities and temperatures. It is found that while the fast ion tail inside the hot spot is significantly depleted, leading to a reduction of the fusion yield in this region, a surplus of fast ions is observed in the neighboring cold plasma region. The presence of this surplus of fast ions in the neighboring cold region is shown to result in a partial recovery of the fusion yield lost in the hot spot.

Physics with fast molecular-ion beams

International Nuclear Information System (INIS)

Kanter, E.P.

1980-01-01

Fast (MeV) molecular-ion beams provide a unique source of energetic projectile nuclei which are correlated in space and time. The recognition of this property has prompted several recent investigations of various aspects of the interactions of these ions with matter. High-resolution measurements on the fragments resulting from these interactions have already yielded a wealth of new information on such diverse topics as plasma oscillations in solids and stereochemical structures of molecular ions as well as a variety of atomic collision phenomena. The general features of several such experiments will be discussed and recent results will be presented

Fast-ion transport during repetitive burst phenomena of toroidal Alfven eigenmodes in the Large Helical Device

International Nuclear Information System (INIS)

Nishiura, M.; Isobe, M.; Yamamoto, S.

2008-10-01

Alfven instabilities induced fast-ion losses have been directly observed for the first time by a newly developed scintillator lost ion probe (SLIP) in the Large Helical Device (LHD). The SLIP can measure the pitch angle and gyro radius of escaped fast ions toward loss region. Neutral beam driven Alfven Eigenmodes (AEs) are excited under the reactor relevant conditions: the ratio of fast ion (beam) speed υ b and Alfven speed υ A is more than 0.3 - 4.0. The beta value for fast ions is considered roughly to be ∼10%. Non-linear phenomena related to Alfven instabilities are observed under such conditions. During repetitive Toroidal Alfven Eigenmode (TAE) bursts, synchronized fast ion losses are observed by SLIP. From the orbit calculation the measured fast ion with pitch angle of 130 degrees and beam energy of 150 keV surely pass through the locations of TAE gaps. The orbit analysis found that the observed fast ions interact strongly with the excited TAEs. This result becomes the first experimental evidence of radial transport of fast ions predicted theoretically during TAE activities. In addition, from the correlation between stored energy degradation and fast-ion loss rate, it is found that fast-ion losses induced by TAE activities with low toroidal mode numbers categorize two phenomena without and with fast- ion loss enhancements, which indicate the fast-ion redistribution and loss. (author)

Evaluation of laser-driven ion energies for fusion fast-ignition research

Science.gov (United States)

Tosaki, S.; Yogo, A.; Koga, K.; Okamoto, K.; Shokita, S.; Morace, A.; Arikawa, Y.; Fujioka, S.; Nakai, M.; Shiraga, H.; Azechi, H.; Nishimura, H.

2017-10-01

We investigate laser-driven ion acceleration using kJ-class picosecond (ps) laser pulses as a fundamental study for ion-assisted fusion fast ignition, using a newly developed Thomson-parabola ion spectrometer (TPIS). The TPIS has a space- and weight-saving design, considering its use in an laser-irradiation chamber in which 12 beams of fuel implosion laser are incident, and, at the same time, demonstrates sufficient performance with its detectable range and resolution of the ion energy required for fast-ignition research. As a fundamental study on laser-ion acceleration using a ps pulse laser, we show proton acceleration up to 40 MeV at 1 × 10^{19} W cm^{-2}. The energy conversion efficiency from the incident laser into protons higher than 6 MeV is 4.6%, which encourages the realization of fusion fast ignition by laser-driven ions.

INTERACTION OF NEUTRAL BEAM INJECTED FAST IONS WITH ION CYCLOTRON RESONANCE FREQUENCY WAVES

International Nuclear Information System (INIS)

CHOI, M.; CHAN, V.S.; CHIU, S.C.; OMELCHENKO, Y.A.; SENTOKU, Y.; STJOH, H.E.

2003-01-01

OAK B202 INTERACTION OF NEUTRAL BEAM INJECTED FAST IONS WITH CYCLOTRON RESONANCE FREQUENCY WAVES. Existing tokamaks such as DIII-D and future experiments like ITER employ both NB injection (NBI) and ion-cyclotron resonance heating (ICRH) for auxiliary heating and current drive. The presence of energetic particles produced by NBI can result in absorption of the Ion cyclotron radio frequency (ICRF) power. ICRF can also interact with the energetic beam ions to alter the characteristics of NBI momentum deposition and resultant impact on current drive and plasma rotation. To study the synergism between NBI and ICRF, a simple physical model for the slowing-down of NB injected fast ions is implemented in a Monte-Carlo rf orbit code. This paper presents the first results. The velocity space distributions of energetic ions generated by ICRF and NBI are calculated and compared. The change in mechanical momentum of the beam and an estimate of its impact on the NB-driven current are presented and compared with ONETWO simulation results

Wave Driven Fast Ion Loss in the National Spherical Torus Experiment

International Nuclear Information System (INIS)

Fredrickson, E.D.; Cheng, C.Z.; Darrow, D.; Fu, G.; Gorelenkov, N.N.; Kramer, G.; Medley, S.S.; Menard, J.; Roquemore, L.; Stutman, D.; White, R.B.

2003-01-01

The study of fast ion instabilities in conventional aspect ratio tokamaks is motivated in large part by their potential to negatively impact the ignition threshold in fusion reactors by causing fast ion losses. Spherical tokamak's (ST), with intrinsically low magnetic fields, are particularly susceptible to fast ion driven instabilities. The 3.5 MeV alpha's from the D-T [deuterium-tritium] fusion reaction in proposed ST reactors will have velocities much higher than the Alfven speed. The Larmor radius of the fusion alphas, normalized to the plasma size, will also be larger than for conventional aspect ratio tokamak reactors. The resulting longer wavelengths of the *AE instabilities will be more effective in driving fast ion loss. The change in magnetic topology also influences the mode structure, as in the case of the Compressional Alfven Eigenmodes (CAE) seen on NSTX

Near midplane scintillator-based fast ion loss detector on DIII-D.

Science.gov (United States)

Chen, X; Fisher, R K; Pace, D C; García-Muñoz, M; Chavez, J A; Heidbrink, W W; Van Zeeland, M A

2012-10-01

A new scintillator-based fast-ion loss detector (FILD) installed near the outer midplane of the plasma has been commissioned on DIII-D. This detector successfully measures coherent fast ion losses produced by fast-ion driven instabilities (≤500 kHz). Combined with the first FILD at ∼45° below the outer midplane [R. K. Fisher, et al., Rev. Sci. Instrum. 81, 10D307 (2010)], the two-detector system measures poloidal variation of losses. The phase space sensitivity of the new detector (gyroradius r(L) ∼ [1.5-8] cm and pitch angle α ∼ [35°-85°]) is calibrated using neutral beam first orbit loss measurements. Since fast ion losses are localized poloidally, having two FILDs at different poloidal locations allows for the study of losses over a wider range of plasma shapes and types of loss orbits.

Methods to determine fast-ion distribution functions from multi-diagnostic measurements

DEFF Research Database (Denmark)

Jacobsen, Asger Schou; Salewski, Mirko

-ion diagnostic views, it is possible to infer the distribution function using a tomography approach. Several inversion methods for solving this tomography problem in velocity space are implemented and compared. It is found that the best quality it obtained when using inversion methods which penalise steep......Understanding the behaviour of fast ions in a fusion plasma is very important, since the fusion-born alpha particles are expected to be the main source of heating in a fusion power plant. Preferably, the entire fast-ion velocity-space distribution function would be measured. However, no fast...

Selective and Efficient Solvent Extraction of Copper(II Ions from Chloride Solutions by Oxime Extractants

Directory of Open Access Journals (Sweden)

Zahra Kaboli Tanha

2016-06-01

Full Text Available Oxime extractants 3-tert-butyl-2-hydroxy-5-methyl benzaldehyde oxime (HL1 and 3-tert-butyl-2-hydroxy-5-methoxy benzaldehyde oxime (HL2 were synthesized and characterized by conventional spectroscopic methods. Suitable lipophilic nature of the prepared extractants allowed examining the ability of these molecules for extraction-separation of copper from its mixture with normally associated metal ions by performing competitive extraction experiments of Cu(II, Co(II, Ni(II, Zn(II, Cd(II and Pb(II ions from chloride solutions. Both ligands transfer selectively the copper ions into dichloromethane by a cation exchange mechanism. Conventional log-log analysis and isotherm curves showed that Cu(II ions are extracted as the complexes with 1:2 metal to ligand ratio by both extractants. Verification of the effect of the organic diluent used in the extraction of copper ions by HL1 and HL2 demonstrated that the extraction efficiency varies as: dichloromethane ~ dichloroethane > toluene > xylene > ethylacetate. Time dependency investigation of the extraction processes revealed that the kinetics of the extraction of copper by HL2 is more rapid than that of HL1. The application of the ligands for extraction-separation of copper ions from leach solutions of cobalt and nickel-cadmium filter-cakes of a zinc production plants was evaluated.

Selective Liquid-Liquid Extraction of Lead Ions Using Newly Synthesized Extractant 2-(Dibutylcarbamoylbenzoic Acid

Directory of Open Access Journals (Sweden)

Hossein Soltani

2015-12-01

Full Text Available A new carboxylic acid extractant, named 2-(dibutylcarbamoylbenzoic acid, is prepared and its potential for selective solvent extraction and recovery of lead ions from industrial samples was investigated. The slope analysis indicated that the lead ions are extracted by formation of 1:2 metal to ligand complexes. The effect of the parameters influencing the extraction efficiency including kind of the organic diluent, extractant concentration, type of the salt used for ionic strength adjustment, contact time and temperature was evaluated and discussed. Under optimized conditions (aqueous phase: 5 ml, initial lead concentration 1 × 10-4 M, pH 4, sodium chloride 0.1 M; organic phase: 5 ml dichloromethane, ligand concentration 0.05 M, a quantitative (75.2 ± 0.8% and highly selective extraction of lead ions in the presence of zinc, nickel, cobalt and cadmium ions (each 1 × 10-4 M was achieved, after 20 min. magnetically stirring of the phases, at      25 °C. The extracted lead ions were stripped from the organic phase by diluted nitric acid (0.1 M solution. The proposed method was successfully applied for separation of lead from industrial samples. The study of the effect of temperature allowed evaluating the thermodynamic parameters of the extraction process of lead ions by the studied extractant into dichloromethane.

Study on fast ion loss in HL-2A tokamak

International Nuclear Information System (INIS)

Liu Yi; Sun Tengfei; Ji Xiaoquan

2012-01-01

Experiments with a high-energy deuterium neutral beam (NB) injection (30 keV, about 0.6 MW) were performed on the HL-2A tokamak. Analysis of neutron decay following the NB 'blip' injection indicates that tangentially injected beam ions are well confined, slowing down classically in the HL-2A. Anomalous losses of beam ions were observed when a beta-induced Alfven acoustic (BAAE) mode was present in the plasma. Such a high energetic particle driven mode led to fast-ion loss, showing a strong influence of the energetic particle driven mode on the fast-ion transport. (authors)

Collision induced fragmentation of fast molecular ions in solids and gases

International Nuclear Information System (INIS)

Gemmell, D.S.

1979-01-01

A brief review is given of recent high resolution measurements on fragments arising from the collision-induced dissociation of fast (MeV) molecular ions. For solid targets, strong wake effects are observed. For gaseous targets, excited electronic states of the projectile ions play an important role. Measurements of this type provide useful information on the charge states of fast ions traversing matter. The experimental techniques show promise as a unique method for determining the geometrical structures of the molecular-ion projectiles. 41 references

Polarization Studies in Fast-Ion Beam Spectroscopy

International Nuclear Information System (INIS)

Trabert, E

2001-01-01

In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams

Measurements and modelling of fast-ion redistribution due to resonant MHD instabilities in MAST

International Nuclear Information System (INIS)

Jones, O M; Cecconello, M; Klimek, I; McClements, K G; Akers, R J; Keeling, D L; Meakins, A J; Sharapov, S E; Boeglin, W U; Perez, R V; Turnyanskiy, M

2015-01-01

The results of a comprehensive investigation into the effects of toroidicity-induced Alfvén eigenmodes (TAE) and energetic particle modes on the NBI-generated fast-ion population in MAST plasmas are reported. Fast-ion redistribution due to frequency-chirping TAE in the range 50 kHz–100 kHz and frequency-chirping energetic particle modes known as fishbones in the range 20 kHz–50 kHz, is observed. TAE and fishbones are also observed to cause losses of fast ions from the plasma. The spatial and temporal evolution of the fast-ion distribution is determined using a fission chamber, a radially-scanning collimated neutron flux monitor, a fast-ion deuterium alpha spectrometer and a charged fusion product detector. Modelling using the global transport analysis code Transp, with ad hoc anomalous diffusion and fishbone loss models introduced, reproduces the coarsest features of the affected fast-ion distribution in the presence of energetic particle-driven modes. The spectrally and spatially resolved measurements show, however, that these models do not fully capture the effects of chirping modes on the fast-ion distribution. (paper)

Space and velocity distributions of fast ions in magnetically confined plasmas

International Nuclear Information System (INIS)

Kolesnichenko, Ya.I.; Lutsenko, V.V.; Lisak, M.; Wising, F.

1994-01-01

General expressions in terms of the orbit averaged distribution function are obtained for local characteristic quantities of fast ions, such as the velocity distribution, energy density and power deposition. The resulting expressions are applied to the case of a very peaked production profile of fast ions, characterized by particularly strong orbital effects. It is shown that in this case the radial profiles of the fast ions can be qualitatively different from the source profile, being e.g. strongly non-monotonic. The analysis is carried out for a straight as well as for a tokamak magnetic field. It is predicted that marginally co-passing and semi-trapped particles (i.e. particles that are trapped in only one azimuthal direction) can be transformed to trapped and circulating particles due to electron drag. This leads to e.g. different distribution functions of fast ions in the cases of co- or counter-injection. Collisional constants of motion are obtained

Influence of RF heating and MHD instabilities on the fast-ion distribution in ASDEX upgrade

Energy Technology Data Exchange (ETDEWEB)

Weiland, Markus

2016-06-07

Fast, supra-thermal ions provide a powerful mechanism to heat fusion plasmas. Through Coulomb collisions with the thermal bulk plasma, they slow down and transfer their energy to the plasma. In present-day devices, fast ions are generated by neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). In future fusion reactors, the dominant heating source, which allows the ignition of a burning plasma, will be fast a-particles resulting from fusion reactions. In addition to plasma heating, fast ions can be utilized to drive plasma currents and rotation. It is therefore crucial for the success of future fusion devices (such as ITER and DEMO) to understand the physics of fast ions and ensure their safe confinement. This thesis focuses both on modeling and experimental aspects. A model to calculate the NBI fast-ion distribution rapidly has been developed. It is based on a combination of existing codes and analytic solutions. Due to the comparably low numerical effort, it can be used to calculate the fast-ion distribution in a large set of discharges, which is used to e.g. improve plasma equilibrium reconstructions. Experimentally, the physics of fast ions is investigated at the tokamak ASDEX Upgrade, using a FIDA (Fast-Ion D-Alpha) spectroscopy diagnostic. This diagnostic technique is based on charge-exchange reactions, that convert the ions into neutral atoms (keeping their momenta). The light emission from these neutral atoms can be collected by optics in the machine and analyzed with spectrometers. Here, the fast-ion contribution can be identified due to large Doppler shifts, and the shape of the spectrum yields information about the velocity distribution. The Doppler shift is given by a projection of the ion velocity vector onto the line of sight, such that observation from different viewing angles is needed to cover the entire velocity space. Therefore, the FIDA diagnostic has been upgraded from three viewing arrays to five, and the spectrometer has

Influence of RF heating and MHD instabilities on the fast-ion distribution in ASDEX upgrade

International Nuclear Information System (INIS)

Weiland, Markus

2016-01-01

Fast, supra-thermal ions provide a powerful mechanism to heat fusion plasmas. Through Coulomb collisions with the thermal bulk plasma, they slow down and transfer their energy to the plasma. In present-day devices, fast ions are generated by neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). In future fusion reactors, the dominant heating source, which allows the ignition of a burning plasma, will be fast a-particles resulting from fusion reactions. In addition to plasma heating, fast ions can be utilized to drive plasma currents and rotation. It is therefore crucial for the success of future fusion devices (such as ITER and DEMO) to understand the physics of fast ions and ensure their safe confinement. This thesis focuses both on modeling and experimental aspects. A model to calculate the NBI fast-ion distribution rapidly has been developed. It is based on a combination of existing codes and analytic solutions. Due to the comparably low numerical effort, it can be used to calculate the fast-ion distribution in a large set of discharges, which is used to e.g. improve plasma equilibrium reconstructions. Experimentally, the physics of fast ions is investigated at the tokamak ASDEX Upgrade, using a FIDA (Fast-Ion D-Alpha) spectroscopy diagnostic. This diagnostic technique is based on charge-exchange reactions, that convert the ions into neutral atoms (keeping their momenta). The light emission from these neutral atoms can be collected by optics in the machine and analyzed with spectrometers. Here, the fast-ion contribution can be identified due to large Doppler shifts, and the shape of the spectrum yields information about the velocity distribution. The Doppler shift is given by a projection of the ion velocity vector onto the line of sight, such that observation from different viewing angles is needed to cover the entire velocity space. Therefore, the FIDA diagnostic has been upgraded from three viewing arrays to five, and the spectrometer has

Determining the stereochemical structures of molecular ions by ''Coulomb-explosion'' techniques with fast (MeV) molecular ion beams

International Nuclear Information System (INIS)

Gemmell, D.S.

1980-01-01

Recent studies on the dissociation of fast (MeV) molecular ion beams in thin foils suggest a novel alternative approach to the determination of molecular ion structures. In this article we review some recent high-resolution studies on the interactions of fast molecular ion beams with solid and gaseous targets and indicate how such studies may be applied to the problem of determining molecular ion structures. The main features of the Coulomb explosion of fast-moving molecular ion projectiles and the manner in which Coulomb-explosion techniques may be applied to the problem (difficult to attack by more conventional means) of determining the stereochemical structures of molecular ions has been described in this paper. Examples have been given of early experiments designed to elicit structure information. The techniques are still in their infancy, and it is to be expected that as both the technology and the analysis are refined, the method will make valuable contributions to the determination of molecular ion structures

Experimental and numerical studies of the fast ions confined in TFR 600 during fast neutrals injection

International Nuclear Information System (INIS)

Gagey, B.

1980-08-01

We present a comparison between experimental fast neutrals spectrum measured with a very simple electrostatic analyzer which has been absolutely calibrated, spectrum obtained during fast neutrals injection in TFR 600, and numerical fast neutrals spectrum obtained from a modified Monte-Carlo calculation code. This comparison allows us to draw important conclusions on the fast ions behavior in the plasma

Scintillator-based diagnostic for fast ion loss measurements on DIII-D

International Nuclear Information System (INIS)

Fisher, R. K.; Van Zeeland, M. A.; Pace, D. C.; Heidbrink, W. W.; Muscatello, C. M.; Zhu, Y. B.; Garcia-Munoz, M.

2010-01-01

A new scintillator-based fast ion loss detector has been installed on DIII-D with the time response (>100 kHz) needed to study energetic ion losses induced by Alfven eigenmodes and other MHD instabilities. Based on the design used on ASDEX Upgrade, the diagnostic measures the pitch angle and gyroradius of ion losses based on the position of the ions striking the two-dimensional scintillator. For fast time response measurements, a beam splitter and fiberoptics couple a portion of the scintillator light to a photomultiplier. Reverse orbit following techniques trace the lost ions to their possible origin within the plasma. Initial DIII-D results showing prompt losses and energetic ion loss due to MHD instabilities are discussed.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-04-08

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

Desorption of organic molecules with fast incident atomic and polyatomic ions

International Nuclear Information System (INIS)

Hunt, J.E.; Salehpour, M.; Fishel, D.L.

1989-01-01

In 1974, Macfarlane and coworkers introduced a new mass spectrometric technique based on desorption-ionization of sample molecules from solid targets by the impact of fast heavy ions (fission fragments) from 252 Cf. The process of ion-induced desorption of molecular ions from surfaces is not yet fully understood, although a large amount of experimental data related to the mechanism has been published. This paper concerns the use of fast incident polyatomic ions to induce desorption of secondary molecular ions of valine and chlorophyll from surfaces. Polyatomic ions are unique in that they are a collection of temporally and spatially correlated atoms. The main finding in this study is that incident polyatomic ions produce drastic enhancements in the secondary ion yields over atomic ions. Also, two types of nonlinear effects in desorption have been observed and will be discussed

Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

International Nuclear Information System (INIS)

Moseev, D.

2011-11-01

Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

Energy Technology Data Exchange (ETDEWEB)

Moseev, D.

2011-11-15

Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

Study of the negative ion extraction mechanism from a double-ion plasma in negative ion sources

International Nuclear Information System (INIS)

Goto, I.; Nishioka, S.; Hatayama, A.; Miyamoto, K.

2015-01-01

We have developed a 2D3V-PIC model of the extraction region, aiming to clarify the basic extraction mechanism of H − ions from the double-ion plasma in H − negative ion sources. The result shows the same tendency of the H − ion density n H − as that observed in the experiments, i.e.,n H − in the upstream region away from the plasma meniscus (H − emitting surface) has been reduced by applying the extraction voltage. At the same time, relatively slow temporal oscillation of the electric potential compared with the electron plasma frequency has been observed in the extraction region. Results of the systematic study using a 1D3V-PIC model with the uniform magnetic field confirm the result that the electrostatic oscillation is identified to be lower hybrid wave. The effect of this oscillation on the H − transport will be studied in the future

Study of the negative ion extraction mechanism from a double-ion plasma in negative ion sources

Energy Technology Data Exchange (ETDEWEB)

Goto, I.; Nishioka, S.; Hatayama, A. [Graduate school of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan)

2015-04-08

We have developed a 2D3V-PIC model of the extraction region, aiming to clarify the basic extraction mechanism of H{sup −} ions from the double-ion plasma in H{sup −} negative ion sources. The result shows the same tendency of the H{sup −} ion density n{sub H{sup −}} as that observed in the experiments, i.e.,n{sub H{sup −}} in the upstream region away from the plasma meniscus (H{sup −} emitting surface) has been reduced by applying the extraction voltage. At the same time, relatively slow temporal oscillation of the electric potential compared with the electron plasma frequency has been observed in the extraction region. Results of the systematic study using a 1D3V-PIC model with the uniform magnetic field confirm the result that the electrostatic oscillation is identified to be lower hybrid wave. The effect of this oscillation on the H{sup −} transport will be studied in the future.

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

Science.gov (United States)

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

2016-02-01

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

Design of fast extraction system for the KEK proton synchrotron

International Nuclear Information System (INIS)

McCarthy, J.D.; Kimura, Yoshitaka.

1975-03-01

A fast beam extraction system is designed for the KEK 12 GeV Proton Synchrotron. The extraction is performed by the multi-turn beam shaving method in which hyper thin electrostatic septum inflectors are used as shaving elements. The beam loss and the emittance of the extracted beam are analyzed numerically as a function of thickness of the electrostatic septum wires. Specifications of the extraction elements, electrostatic septa, fast and slow bumps, and septum magnets, are given for the configuration of the designed system. (auth.)

Scaling Trapped Ion Quantum Computers Using Fast Gates and Microtraps

Science.gov (United States)

Ratcliffe, Alexander K.; Taylor, Richard L.; Hope, Joseph J.; Carvalho, André R. R.

2018-06-01

Most attempts to produce a scalable quantum information processing platform based on ion traps have focused on the shuttling of ions in segmented traps. We show that an architecture based on an array of microtraps with fast gates will outperform architectures based on ion shuttling. This system requires higher power lasers but does not require the manipulation of potentials or shuttling of ions. This improves optical access, reduces the complexity of the trap, and reduces the number of conductive surfaces close to the ions. The use of fast gates also removes limitations on the gate time. Error rates of 10-5 are shown to be possible with 250 mW laser power and a trap separation of 100 μ m . The performance of the gates is shown to be robust to the limitations in the laser repetition rate and the presence of many ions in the trap array.

Sheath formation and extraction of ions from a constricted R.F ion source

Energy Technology Data Exchange (ETDEWEB)

Abdel-Salam, F W; Helal, A G; El-Khabeary, H; El-Merai, N T [Accelerators Dept., Nuclear Research Center, Atomic Energy Authority, Cairo, (Egypt)

1997-12-31

The present work investigates the plasma characteristics in a constricted R. F. ion source. The extraction of ions from the plasma boundary and sheath formation were studied. The ion source physical parameters are discussed in order to understand the physical processes occurring within the discharge region up to the extraction system. Electron temperature and density were determined using Langmuir probe. The probe current-voltage characteristics were measured for different extraction voltages (ext.) = 0,500,1000, and 1250 volt at various constant R.F. powers. The effect of R.F. power on electron temperature was deduced for a beam = plasma discharge. This revealed that for a quasi-neutral (plasma) region the electron temperature increased linearly with the R.F. Power which leads to substantial electron heating and efficient electron energy transport in this region. Applying extraction voltage, the electron temperature drops as the ionization rate increases. The sheath thickness was obtained at constant extraction voltages. The curves show that if the ion current density increased, the sheath thickness decreased while it increases by increasing extraction voltage, and it is negligible in the plasma region. 13 figs.

Electronic excitations in fast ion-solid collisions

International Nuclear Information System (INIS)

Burgdoerfer, J.

1990-01-01

We review recent developments in the study of electronic excitation of projectiles in fast ion-solid collisions. Our focus will be primarily on theory but experimental advances will also be discussed. Topics include the evidence for velocity-dependent thresholds for the existence of bound states, wake-field effects on excited states, the electronic excitation of channeled projectiles, transport phenomena, and the interaction of highly charged ions with surfaces. 44 refs., 14 figs

Two-dimensional particle simulation of negative ion extraction from a volume source

International Nuclear Information System (INIS)

Naitou, H.; Fukumasa, O.; Sakachou, K.; Mutou, K.

1995-01-01

Two-dimensional electrostatic particle simulation was done to study the extraction of negative ions from a volume plasma source. The simulation model is a rectangular system which consists of an extraction grid, a plasma grid, and a grounded wall. Full dynamics of electrons, ions, and negative ions are followed. Negative ions are extracted from the plasma region to the extraction grid through a slit in the plasma grid. For the lower value of extraction grid potential, the simulation results agree with the Child-Langumuir law, where the extracted negative ion current is proportional to the three-halves power of the potential of the extraction grid. For the higher value of extraction grid potential, the space charge effect of negative ions, which enter into the beamline at the top of the concavity of the positive ion boundary, reduces the negative ion current from the prediction of the Child-Langumuir law. ((orig.))

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-02-15

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

Validation of fast-ion D-alpha spectrum measurements during EAST neutral-beam heated plasmas

Energy Technology Data Exchange (ETDEWEB)

Huang, J., E-mail: juan.huang@ipp.ac.cn; Wu, C. R.; Hou, Y. M.; Chang, J. F.; Ding, S. Y.; Chen, Y. J.; Jin, Z.; Xu, Z.; Gao, W.; Wang, J. F.; Lyu, B.; Zang, Q.; Zhong, G. Q.; Hu, L.; Wan, B. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031 Hefei, Anhui (China); Heidbrink, W. W.; Stagner, L.; Zhu, Y. B. [University of California, Irvine, California 92697 (United States); Hellermann, M. G. von [Diagnostic Team, ITER Organization, Route de Vinon-sur-Verdon 13067 St. Paul Lez Durance (France)

2016-11-15

To investigate the fast ion behavior, a fast ion D-alpha (FIDA) diagnostic system has been installed on EAST. Fast ion features can be inferred from the Doppler shifted spectrum of Balmer-alpha light from energetic hydrogenic atoms. This paper will focus on the validation of FIDA measurements performed using MHD-quiescent discharges in 2015 campaign. Two codes have been applied to calculate the D{sub α} spectrum: one is a Monte Carlo code, Fortran 90 version FIDASIM, and the other is an analytical code, Simulation of Spectra (SOS). The predicted SOS fast-ion spectrum agrees well with the measurement; however, the level of fast-ion part from FIDASIM is lower. The discrepancy is possibly due to the difference between FIDASIM and SOS velocity distribution function. The details will be presented in the paper to primarily address comparisons of predicted and observed spectrum shapes/amplitudes.

A Study on the Ion Beam Extraction using Duo-PiGatron Ion source for Vertical Type Ion Beam Facility

Energy Technology Data Exchange (ETDEWEB)

Kim, Bom Sok; Lee, Chan young; Lee, Jae Sang [KAERI, Daejeon (Korea, Republic of)

2015-05-15

In Korea Multipurpose Accelerator Complex (KOMAC), we have started ion beam service in the new beam utilization building since March this year. For various ion beam irradiation services, we are developed implanters such as metal (150keV/1mA), gaseous (200keV/5mA) and high current ion beam facility (20keV/150mA). One of the new one is a vertical type ion beam facility without acceleration tube (60keV/20mA) which is easy to install the sample. After the installation is complete, it is where you are studying the optimal ion beam extraction process. Detailed experimental results will be presented. Vertical Type Ion Beam Facility without acceleration tube of 60keV 20mA class was installed. We successfully extracted 60keV 20mA using Duo- PiGatron Ion source for Vertical Type Ion Beam Facility. Use the BPM and Faraday-cup, is being studied the optimum conditions of ion beam extraction.

Ion extraction from positively biased laser-ablation plasma

International Nuclear Information System (INIS)

Isono, Fumika; Nakajima, Mitsuo; Hasegawa, Jun; Horioka, Kazuhiko

2016-01-01

Ions were extracted through a grounded grid from a positively biased laser-ablation plasma and the behaviors were investigated. Since the plasma was positively biased against the grounded wall, we could extract the ions without insulated gap. We confirmed formation of a virtual anode when we increased the distance between the grid and the ion collector. Results also indicated that when the ion flux from the ablation plasma exceeded a critical value, the current was strongly suppressed to the space charge limited level due to the formation of virtual anode.

An attempt to fabricate an ion injection type fast neutron dosimeter

International Nuclear Information System (INIS)

Pells, G.P.; Hughes, A.E.

1976-10-01

This report describes the results of work carried out to investigate a novel type of solid state, fast neutron dosimeter. The concept and quantitative features of the dosimeter, in which collisions between fast neutrons and ions in a source compound cause the ions to be injected into a host compound where they could then be detected by their characteristic luminescence, are described. It is shown that with the aid of a complex reader mrad sensitivities should in principle be possible. Initial experiments showed that accelerator implantation of Bi 3+ ions into CaO gives a linear dependence of luminescence output with fluence of activator ions. A number of host/activator combinations were investigated from which SiO 2 :Gd 3+ appeared the most promising. Host/activator configurations are briefly considered. The production of compacts of SiO 2 and Gd 2 O 3 ultrafine powders is described. Attempts were made to characterise these compacts using scanning electron microscopy and luminescence spectroscopy. After fast neutron irradiation to 250 Mrad no Gd 3+ ion injection could be detected. An alternative configuration of ultrafine SiO 2 powder dispersed in a solid Gd(NO 3 ) 3 .5H 2 O matrix is described but again no Gd 3+ ion injection into the SiO 2 could be detected after fast neutron irradiation. Perspex, as a host, was also tried without success. An appendix is included which demonstrates that the lack of success in detecting ion-injection may be largely due to the optically opaque nature of the specimens that could be produced. (author)

Fast neutron dose equivalent rates in heavy ion target areas

Energy Technology Data Exchange (ETDEWEB)

Fulmer, C.B.; Butler, H.M.; Ohnesorge, W.F.; Mosko, S.W.

1978-01-01

At heavy ion accelerators, personnel access to areas near the target is sometimes important for successful performance of experiments. Radiation levels determine the amount of time that can be spent in these areas without exceeding maximum permissible exposures. Inasmuch as the fast neutrons contribute the major part of the Rem dose rates in these areas, knowledge of the fast neutron levels is important for planning permissive entry to target areas. Fast neutron dose rates were measured near thick medium mass targets bombarded with beams of C, N, O, and Ne ions. beam energies ranged from 3 to 16 MeV/amu. Dose rates (mrem/h) 1 meter from the target 90 degrees from the beam direction range from approx. 0.05 at MeV/amu to approx. 50 at 16 MeV/amu. These data should be helpful in planning permissive entry to heavy ion target areas.

Fast neutron dose equivalent rates in heavy ion target areas

International Nuclear Information System (INIS)

Fulmer, C.B.; Butler, H.M.; Ohnesorge, W.F.; Mosko, S.W.

1978-01-01

At heavy ion accelerators, personnel access to areas near the target is sometimes important for successful performance of experiments. Radiation levels determine the amount of time that can be spent in these areas without exceeding maximum permissible exposures. Inasmuch as the fast neutrons contribute the major part of the Rem dose rates in these areas, knowledge of the fast neutron levels is important for planning permissive entry to target areas. Fast neutron dose rates were measured near thick medium mass targets bombarded with beams of C, N, O, and Ne ions. beam energies ranged from 3 to 16 MeV/amu. Dose rates (mrem/h) 1 meter from the target 90 degrees from the beam direction range from approx. 0.05 at MeV/amu to approx. 50 at 16 MeV/amu. These data should be helpful in planning permissive entry to heavy ion target areas

Bootstrap current of fast ions in neutral beam injection heating

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Li Xinxia; Yu Jun

2012-01-01

The bootstrap current of fast ions produced by neutral beam injection (NBI) is investigated in a large-aspect-ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are reported. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current taken into consideration, the net current density obviously decreases; at the same time, the peak of the current moves towards the central plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the NBI but also on the ratio of the velocity of fast ions to the critical velocity: the value of the net current is small for neutral beam parallel injection, but increases severalfold for perpendicular injection, and increases with increasing beam energy. (paper)

Neutralization principles for the Extraction and Transport of Ion Beams

CERN Document Server

Riege, H

2000-01-01

The strict application of conventional extraction techniques of ion beams from a plasma source is characterized by a natural intensity limit determined by space charge.The extracted current may be enhanced far beyond this limit by neutralizing the space charge of the extracted ions in the first extraction gap of the source with electrons injected from the opposite side. The transverse and longitudinal emittances of a neutralized ion beam, hence its brightness, are preserved. Results of beam compensation experiments, which have been carried out with a laser ion source, are resumed for proposing a general scheme of neutralizing ion sources and their adjacent low-energy beam transport channels with electron beams. Many technical applications of high-mass ion beam neutralization technology may be identified: the enhancement of ion source output for injection into high-intensity, low-and high-energy accelerators, or ion thrusters in space technology, for the neutral beams needed for plasma heating of magnetic conf...

Axial magnetic field extraction type microwave ion source with a permanent magnet

International Nuclear Information System (INIS)

Ishikawa, Junzo; Takagi, Toshinori

1984-01-01

A new type of microwave ion source in which a permanent magnet generates an axially directed magnetic field needed for the electron cyclotron resonance was developed. The electron cyclotron resonance produces a high density plasma in the ion source. A mA-order ion beam can be extracted. Compared with usual microwave ion sources, this source has a distinguished feature in that the axially directed magnetic field is formed by use of a permanent magnet. Shape of magnetic force lines near the ion extraction aperture was carefully investigated. The extracted ion current as a function of the ion extraction voltage was measured. The experimental data are in good agreement with the theoretical line. The ion source can be heated up to 500 deg C, and extraction of the alkaline metal ions is possible. The extracted ion current for various elements are shown in the table. The current density normalized by the proton was 350-650 mA/cm 2 which was nearly equal to the upper limit of the extractable positive ion current density. The plasma density was estimated and was 2 - 3 x 10 12 cm -3 . The mass spectrum of a Cesium ion beam was obtained. A negligible amount of impurities was observed. The emittance diagram of the extracted ion beam was measured. The result shows that a low emittance and high brightness ion source is constructed. (Kato, T.)

Global marginal stability of TAEs in the presence of fast ions

International Nuclear Information System (INIS)

Villard, L.; Brunner, S.; Vaclavik, J.

1994-09-01

The global stability of toroidicity-induced Alfven eigenmodes (TAEs) in the presence of fast ions in realistic tokamak fusion-grade plasmas is analyzed with a global, perturbative approach. Volume averaged fast particle betas for marginal stability are obtained and analyzed for a wide range of plasma parameters such as the fast ion radial density profile width, the ratio of birth velocity to the Alfven velocity on axis and the bulk plasma beta. The different stability behaviour of two types of TAEs ('internal' or 'external') is evidenced. (author) 19 figs., 22 refs

A linear ion optics model for extraction from a plasma ion source

International Nuclear Information System (INIS)

Dietrich, J.

1987-01-01

A linear ion optics model for ion extraction from a plasma ion source is presented, based on the paraxial equations which account for lens effects, space charge and finite source ion temperature. This model is applied to three- and four-electrode extraction systems with circular apertures. The results are compared with experimental data and numerical calculations in the literature. It is shown that the improved calculations of space charge effects and lens effects allow better agreement to be obtained than in earlier linear optics models. A principal result is that the model presented here describes the dependence of the optimum perveance on the aspect ratio in a manner similar to the nonlinear optics theory. (orig.)

Energetic-particle-driven instabilities and induced fast-ion transport in a reversed field pinch

International Nuclear Information System (INIS)

Lin, L.; Brower, D. L.; Ding, W. X.; Anderson, J. K.; Capecchi, W.; Eilerman, S.; Forest, C. B.; Koliner, J. J.; Nornberg, M. D.; Reusch, J.; Sarff, J. S.; Liu, D.

2014-01-01

Multiple bursty energetic-particle (EP) driven modes with fishbone-like structure are observed during 1 MW tangential neutral-beam injection in a reversed field pinch (RFP) device. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal magnetic field (leading to stronger drive), provide a complementary environment to tokamak and stellarator configurations for exploring basic understanding of EP instabilities. Detailed measurements of the EP mode characteristics and temporal-spatial dynamics reveal their influence on fast ion transport. Density fluctuations exhibit a dynamically evolving, inboard-outboard asymmetric spatial structure that peaks in the core where fast ions reside. The measured mode frequencies are close to the computed shear Alfvén frequency, a feature consistent with continuum modes destabilized by strong drive. The frequency pattern of the dominant mode depends on the fast-ion species. Multiple frequencies occur with deuterium fast ions compared to single frequency for hydrogen fast ions. Furthermore, as the safety factor (q) decreases, the toroidal mode number of the dominant EP mode transits from n=5 to n=6 while retaining the same poloidal mode number m=1. The transition occurs when the m=1, n=5 wave-particle resonance condition cannot be satisfied as the fast-ion safety factor (q fi ) decreases. The fast-ion temporal dynamics, measured by a neutral particle analyzer, resemble a classical predator-prey relaxation oscillation. It contains a slow-growth phase arising from the beam fueling followed by a rapid drop when the EP modes peak, indicating that the fluctuation-induced transport maintains a stiff fast-ion density profile. The inferred transport rate is strongly enhanced with the onset of multiple EP modes

Dynamics of fast ions during sawtooth oscillations in the TEXTOR tokamak measured by collective Thomson scattering

DEFF Research Database (Denmark)

Nielsen, Stefan Kragh; Salewski, Mirko; Bindslev, Henrik

2011-01-01

Experimental investigations of sawteeth interaction with fast ions measured by collective Thomson scattering on TEXTOR are presented. Time-resolved measurements of localized 1D fast-ion distribution functions allow us to study fast-ion dynamics during several sawtooth cycles. Sawtooth oscillation...

Bootstrap current of fast ions in neutral beam injection heating

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Yang Lei; Li Xinxia; Lu Xingqiang; Yu Jun

2012-01-01

The bootstrap current of fast ions produced by the neutral beam injection is investigated in a large aspect ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are figured out. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current considered, the net current density obviously decreases due to electron return current, at the same time the peak of current moves towards the centre plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the neutral beam injection but also on the ratio of the velocity of fast ions to the critical velocity: the value of net current is small for the neutral beam parallel injection but increases multipliedly for perpendicular injection, and increases with beam energy increasing. (authors)

Kinetic-magnetohydrodynamic simulation study of fast ions and toroidal Alfven eigenmodes

International Nuclear Information System (INIS)

Todo, Y.; Sato, T.

2001-01-01

Particle-magnetohydrodynamic and Fokker-Planck-magnetohydrodynamic simulations of fast ions and toroidicity-induced Alfven eigenmodes (TAE modes) have been carried out. Alpha particle losses induced by TAE mode are investigated with particle-magnetohydrodynamic simulations. Trapped particles near the passing-trapped boundary in the phase space are also lost appreciably in addition to the counter-passing particles. In Fokker-Planck-magnetohydrodynamic simulation source and slowing-down of fast ions are considered. A coherent pulsating behavior of multiple TAE modes, which occurs in neutral beam injection experiments, is observed when the slowing-down time is much longer than the damping time of the TAE modes and the fast-ion pressure is sufficiently high. For a slowing-down time comparable to the damping time, the TAE modes reach steady saturation levels. (author)

Kinetic-magnetohydrodynamic simulation study of fast ions and toroidal Alfven eigenmodes

International Nuclear Information System (INIS)

Todo, Y.; Sato, T.

1999-01-01

Particle-magnetohydrodynamic and Fokker-Planck-magnetohydrodynamic simulations of fast ions and toroidicity-induced Alfven eigenmodes (TAE modes) have been carried out. Alpha particle losses induced by TAE mode are investigated with particle-magnetohydrodynamic simulations. Trapped particles near the passing-trapped boundary in the phase space are also lost appreciably in addition to the counter-passing particles. In Fokker-Planck-magnetohydrodynamic simulation source and slowing-down of fast ions are considered. A coherent pulsating behavior of multiple TAE modes, which occurs in neutral beam injection experiments, is observed when the slowing-down time is much longer than the damping time of the TAE modes and the fast-ion pressure is sufficiently high. For a slowing-down time comparable to the damping time, the TAE modes reach steady saturation levels. (author)

Metal ion extractant in microemulsions: where solvent extraction and surfactant science meet

International Nuclear Information System (INIS)

Bauer, C.

2011-01-01

The presented work describes the supramolecular structure of mixtures of a hydrophilic surfactant n-octyl-beta-glucoside (C8G1), and the hydrophobic metal ion extractant tributylphosphate (TBP) in n-dodecane/water as well as in the presence of salts. In the first part, basic solvent extraction system, composed of water, oil and extractant, will be introduced. The focus, however, lies on the extraction of multivalent metal ions from the aqueous phase. During this extraction process and in the following thermodynamic equilibrium, aggregation and phase transition in supramolecular assemblies occur, which are already described in literature. Notably, these reports rest on individual studies and specific conclusions, while a general concept is still missing. We therefore suggest the use of generalized phase diagrams to present the physico-chemical behaviour of (amphiphilic) extractant systems. These phase diagrams facilitated the development of a thermodynamic model based on molecular geometry and packing of the extractant molecules in the oil phase. As a result, we are now in the position to predict size and water content of extractant aggregates and, thus, verify the experimental results by calculation.Consequently, the second part presents a systematic study of the aqueous and organic phase of water/C8G1 and water/oil/TBP mixtures. The focus lies on understanding the interaction between metal ions and both amphiphilic molecules by means of small angle x-ray scattering (SAXS), dynamic light scattering (DLS) and UV-Vis spectroscopy. We confirmed the assumption that extraction of metal ions is driven by TBP, while C8G1 remains passive. In the third and last part, microemulsions of C8G1, TBP, water (and salt) and n-dodecane are characterized by small angle neutron scattering (SANS), and chemical analytics (Karl Fischer, total organic carbon, ICP-OES,...). The co-surfactant behaviour of TBP was highlighted by comparison to the classical n-alcohol (4≤n≤8) co

Recent work with fast molecular-ion beams at Argonne National Laboratory

International Nuclear Information System (INIS)

Cooney, P.J.; Gemmell, D.S.; Groeneveld, K.O.; Kanter, E.P.; Pietsch, W.J.; Vager, Z.; Zabransky, B.J.

1979-01-01

Research in these areas during 1979 is summarized: (a) studies of molecular-ion dissociation in gaseous targets, (b) developing an understanding of the origins of central peaks and of the two phenomena of the transmission of fast molecular ions through thin foil targets and of the production of neutral fragments from collision-induced dissociation of fast molecular projectiles, (c) studies exploring the extent to which high-resolution measurements on dissociation fragments can be used to determine the stereochemical structures of the molecular ions in the incident beam, (d) extensive modifications to the beam-line and apparatus at the 4-MV Dynamitron so as to permit a wide variety of coincidence measurements on fragments from collision-induced molecular-ion dissociation

Calculation Of Extraction Optics For Ion System With Plazma Emitter

CERN Document Server

Frolov, B A

2004-01-01

The 2-D code for simulating of ion optics system of positive ion extraction from a plasma source is described. Example calculation of 100 kV optics for the extraction ion IHEP gun is presented. The trajectories of particles and emittance plots are resulted. The aberrations influ-ence strongly on ion optics for considered geometry.

Solvent extraction of titanium(IV), zirconium(IV) and hafnium(IV) salicylates using liquid ion exchangers

Energy Technology Data Exchange (ETDEWEB)

Sundaramurthi, N M; Shinde, V M

1989-02-01

A solvent extraction method is proposed for the extraction of quadrivalent titanium, zirconium an hafnium from salicylate media using liquid ion exchangers such as Aliquat 336 and trioctylamine dissolved in xylene. The optimum conditions were evaluated from a critical study of the following: pH, salicylate concentration, amine concentration, diluent and period of equilibration. The method allows the separation of titanium, zirconium and hafnium from binary mixtures containing commonly associated metal ions and is applicable to the analysis of real samples such as BCS-CRM 387 nimonic 901, BCS-CRM 243/4 ferro-titanium, BCS-CRM 307 magnesium alloy and BCS-CRM 388 zircon. Titanium is determined either with hydrogen peroxide or by atomic absorption spectrometry whereas zirconium and hafnium are determined spectrophotometrically with Alizarin Red S and Zylenol Orange, respectively. The results of both separation and analysis are reported. The method is precise, accurate and fast.

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

International Nuclear Information System (INIS)

Heidbrink, W.W.

1984-02-01

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

Fast-ion transport in the presence of magnetic reconnection induced by sawtooth oscillations in ASDEX Upgrade

NARCIS (Netherlands)

Geiger, B.; M. García-Muñoz,; Dux, R.; Ryter, F.; Tardini, G.; Orte, L. B.; Classen, I.G.J.; Fable, E.; Fischer, R.; Igochine, V.; McDermott, R. M.

2014-01-01

The transport of beam-generated fast ions has been investigated experimentally at the ASDEX Upgrade tokamak in the presence of sawtooth crashes. After sawtooth crashes, phase space resolved fast-ion D-alpha measurements show a significant reduction of the central fast-ion density-more than

Fast-ion losses induced by ELMs and externally applied magnetic perturbations in the ASDEX Upgrade tokamak

International Nuclear Information System (INIS)

Garcia-Munoz, M; Rodriguez-Ramos, M; Äkäslompolo, S; De Marne, P; Dunne, M G; Dux, R; Fietz, S; Fuchs, C; Geiger, B; Herrmann, A; Hoelzl, M; Kurzan, B; McDermott, R M; Strumberger, E; Evans, T E; Ferraro, N M; Pace, D C; Lazanyi, N; Nocente, M; Shinohara, K

2013-01-01

Phase-space time-resolved measurements of fast-ion losses induced by edge localized modes (ELMs) and ELM mitigation coils have been obtained in the ASDEX Upgrade tokamak by means of multiple fast-ion loss detectors (FILDs). Filament-like bursts of fast-ion losses are measured during ELMs by several FILDs at different toroidal and poloidal positions. Externally applied magnetic perturbations (MPs) have little effect on plasma profiles, including fast-ions, in high collisionality plasmas with mitigated ELMs. A strong impact on plasma density, rotation and fast-ions is observed, however, in low density/collisionality and q 95 plasmas with externally applied MPs. During the mitigation/suppression of type-I ELMs by externally applied MPs, the large fast-ion bursts observed during ELMs are replaced by a steady loss of fast-ions with a broad-band frequency and an amplitude of up to an order of magnitude higher than the neutral beam injection (NBI) prompt loss signal without MPs. Multiple FILD measurements at different positions, indicate that the fast-ion losses due to static 3D fields are localized on certain parts of the first wall rather than being toroidally/poloidally homogeneously distributed. Measured fast-ion losses show a broad energy and pitch-angle range and are typically on banana orbits that explore the entire pedestal/scrape-off-layer (SOL). Infra-red measurements are used to estimate the heat load associated with the MP-induced fast-ion losses. The heat load on the FILD detector head and surrounding wall can be up to six times higher with MPs than without 3D fields. When 3D fields are applied and density pump-out is observed, an enhancement of the fast-ion content in the plasma is typically measured by fast-ion D-alpha (FIDA) spectroscopy. The lower density during the MP phase also leads to a deeper beam deposition with an inward radial displacement of ≈2 cm in the maximum of the beam emission. Orbit simulations are used to test different models for 3D

Glancing-angle scattering of fast ions at crystal surfaces

Energy Technology Data Exchange (ETDEWEB)

Mannami, Michihiko; Narumi, Kazumasa; Katoh, Humiya; Kimura, Kenji [Kyoto Univ. (Japan). Faculty of Engineering

1997-03-01

Glancing angle scattering of fast ions from a single crystal surface is a novel technique to study ion-surface interaction. Results of recent studies of ion-surface interaction are reviewed for ions with velocities faster than the Fermi velocity of solid. For the ions with velocities less than the Fermi velocity of target valence electrons the ion-surface interaction shows a new aspect where only the valence electrons of target solid participate in the stopping processes. It will show that the position-dependent stopping power of a surface for these ions governed by the elastic collisions of valence electrons and the ions. A method is proposed from this position-dependent stopping power to derived the electron density distribution averaged over the plane parallel to the surface. (author)

Simulation studies of the extraction region from glow discharge ion sources

International Nuclear Information System (INIS)

Abdelrahman, M.M.

2012-01-01

This paper studies the influence of various parameters and conditions on the performance of an ion-beam extraction system, the trajectories of the particles in the beam being simulated by a commercial software (SIMION 3D). Space-charge effects are accounted for and criteria allowing optimization of the system are proposed. Ion beam trajectories with and without space charge have been determined and, from the results, optimum extraction conditions have been deduced. Simulation of singly charged ion trajectories for a concave meniscus with 3.5 mm curvature radius was studied with and without space charge has been done using a singly charge argon ion trajectories. Firstly, for a concave meniscus with 3.5 mm curvature radius, the influence of the current density on the ion beam shape was investigated. Furthermore, influence of the extraction voltage applied to the extraction electrode on the ion beam envelope was studied. Finally, the influence of the extraction gap width on the ion beam envelope was also studied

Extraction of space-charge-dominated ion beams from an ECR ion source: Theory and simulation

Science.gov (United States)

Alton, G. D.; Bilheux, H.

2004-05-01

Extraction of high quality space-charge-dominated ion beams from plasma ion sources constitutes an optimization problem centered about finding an optimal concave plasma emission boundary that minimizes half-angular divergence for a given charge state, independent of the presence or lack thereof of a magnetic field in the extraction region. The curvature of the emission boundary acts to converge/diverge the low velocity beam during extraction. Beams of highest quality are extracted whenever the half-angular divergence, ω, is minimized. Under minimum half-angular divergence conditions, the plasma emission boundary has an optimum curvature and the perveance, P, current density, j+ext, and extraction gap, d, have optimum values for a given charge state, q. Optimum values for each of the independent variables (P, j+ext and d) are found to be in close agreement with those derived from elementary analytical theory for extraction with a simple two-electrode extraction system, independent of the presence of a magnetic field. The magnetic field only increases the emittances of beams through additional aberrational effects caused by increased angular divergences through coupling of the longitudinal to the transverse velocity components of particles as they pass though the mirror region of the electron cyclotron resonance (ECR) ion source. This article reviews the underlying theory of elementary extraction optics and presents results derived from simulation studies of extraction of space-charge dominated heavy-ion beams of varying mass, charge state, and intensity from an ECR ion source with emphasis on magnetic field induced effects.

Extraction of space-charge-dominated ion beams from an ECR ion source: Theory and simulation

International Nuclear Information System (INIS)

Alton, G.D.; Bilheux, H.

2004-01-01

Extraction of high quality space-charge-dominated ion beams from plasma ion sources constitutes an optimization problem centered about finding an optimal concave plasma emission boundary that minimizes half-angular divergence for a given charge state, independent of the presence or lack thereof of a magnetic field in the extraction region. The curvature of the emission boundary acts to converge/diverge the low velocity beam during extraction. Beams of highest quality are extracted whenever the half-angular divergence, ω, is minimized. Under minimum half-angular divergence conditions, the plasma emission boundary has an optimum curvature and the perveance, P, current density, j +ext , and extraction gap, d, have optimum values for a given charge state, q. Optimum values for each of the independent variables (P, j +ext and d) are found to be in close agreement with those derived from elementary analytical theory for extraction with a simple two-electrode extraction system, independent of the presence of a magnetic field. The magnetic field only increases the emittances of beams through additional aberrational effects caused by increased angular divergences through coupling of the longitudinal to the transverse velocity components of particles as they pass though the mirror region of the electron cyclotron resonance (ECR) ion source. This article reviews the underlying theory of elementary extraction optics and presents results derived from simulation studies of extraction of space-charge dominated heavy-ion beams of varying mass, charge state, and intensity from an ECR ion source with emphasis on magnetic field induced effects

On fast-ion transport and burn control in Tokamaks

International Nuclear Information System (INIS)

Wising, F.

1994-01-01

Fast ions, generated by e.g. neutral beam injection (NBI), radio frequency (RF) heating or nuclear reactions, play an important role in all large tokamaks. Several issues related to fast ions and burning fusion plasmas are addressed in this thesis. Firstly, a new model of sawtooth oscillations is developed which explains the recent observations that q 0 remains below unity during the entire sawtooth cycle. The model features full reconnection in two current layers and provides a self-consistent description of the plasma states before and after the sawtooth crash. It is applied to the redistribution of fast NBI-ions in JET and comparisons are made with global as well as line-of-sight integrated D-D neutron measurements. Both the new model and the classical Kadomtsev model are found to be in agreement with the measurements. A simplified redistribution model is developed and applied to the redistribution of tritons and thermal ions, again giving reasonable agreement with D-T/D-D neutron measurements. Using a separate method, earlier results on expulsion of NBI-ions are confirmed. Secondly, a numerical study has been carried out of the coupled nonlinear evolution of alpha-particle driven kinetic Alfven wave turbulence and associated alpha transport. The saturated fluctuation spectrum consists of two peaks and results from nonlinear ion Compton scattering-induced transfer of energy from longer to shorter wavelengths. An analytical solution of the saturated spectrum, and estimates of the anomalous alpha diffusion coefficient, are given. The final paper addresses the problem of determining whether an initial temperature profile, established by e.g. auxiliary heating, will evolve to thermonuclear burn or quench under the influence of alpha particle heating and thermal conduction. Explicit burn criteria are presented and the beneficial effects of density and temperature peaking are discussed. 110 refs

Measurements of Prompt and MHD-Induced Fast Ion Loss from National Spherical Torus Experiment Plasmas

Energy Technology Data Exchange (ETDEWEB)

D.S. Darrow; S.S. Medley; A.L. Roquemore; W.W. Heidbrink; A. Alekseyev; F.E. Cecil; J. Egedal; V.Ya. Goloborod' ko; N.N. Gorelenkov; M. Isobe; S. Kaye; M. Miah; F. Paoletti; M.H. Redi; S.N. Reznik; A. Rosenberg; R. White; D. Wyatt; V.A. Yavorskij

2002-10-15

A range of effects may make fast ion confinement in spherical tokamaks worse than in conventional aspect ratio tokamaks. Data from neutron detectors, a neutral particle analyzer, and a fast ion loss diagnostic on the National Spherical Torus Experiment (NSTX) indicate that neutral beam ion confinement is consistent with classical expectations in quiescent plasmas, within the {approx}25% errors of measurement. However, fast ion confinement in NSTX is frequently affected by magnetohydrodynamic (MHD) activity, and the effect of MHD can be quite strong.

Power deposition by neutral beam injected fast ions in field-reversed configurations

International Nuclear Information System (INIS)

Takahashi, Toshiki; Kato, Takayuki; Kondoh, Yoshiomi; Iwasaka, Naotaka

2004-04-01

Effects of Coulomb collisions on neutral beam (NB) injected fast ions into Field-Reversed Configuration (FRC) plasmas are investigated by calculating the single particle orbits, where the ions are subject to the slowing down and pitch angle collisions. The Monte-Carlo method is used for the pitch angle scattering, and the friction term is added to the equation of motion to show effects of slowing down collision such as the deposited power profile. Calculation parameters used are relevant to the NB injection on the FRC Injection Experiment (FIX) device. It is found that the dominant local power deposition occurs in the open field region between the X-point and the mirror point because of a concentration of fast ions and a longer duration travel at the mirror reflection point. In the present calculation, the maximum deposited power to the FRC plasma is about 10% of the injected power. Although the pitch angle scattering by Coulomb collision destroys the mirror confinement of NB injected fast ions, this effect is found negligible. The loss mechanism due to non-adiabatic fast ion motion, which is intrinsic in non-uniform FRC plasmas, affects much greater than the pitch angle scattering by Coulomb collision. (author)

Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

NARCIS (Netherlands)

M. García-Muñoz,; Hicks, N.; van Voornveld, R.; Classen, I.G.J.; Bilato, R.; Bobkov, V.; Brambilla, M.; Bruedgam, M.; Fahrbach, H. U.; Igochine, V.; Jaemsae, S.; Maraschek, M.; Sassenberg, K.

2010-01-01

The phase-space of convective and diffusive fast-ion losses induced by shear Alfven eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfven eigenmodes (TAEs) and Alfven

Poly(1-vinylimidazole) functionalized magnetic ion imprinted polymer for fast and selective extraction of trace gold in geological, environmental and biological samples followed by graphite furnace atomic absorption spectrometry detection

Science.gov (United States)

Zhao, Bingshan; He, Man; Chen, Beibei; Xu, Hongrun; Hu, Bin

2018-05-01

In this study, poly(1-vinylimidazole) functionalized gold ion imprinted polymer coated magnetic nanoparticles (MNPs@PVIM-Au-IIP) were prepared and characterized. The adsorption behaviors of the prepared MNPs@PVIM-Au-IIP toward gold ions (Au(III)) were studied, it was found that MNPs@PVIM-Au-IIP has good selectivity, high adsorption capacity (185.4 mg g-1) and fast adsorption kinetic for Au(III). Based on it, a new method of ion imprinted magnetic solid phase extraction (II-MSPE) coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection was proposed for the analysis of trace Au(III) in real samples with complicated matrix. Factors affecting MSPE including sample pH, desorption reagent, elution concentration and volume, elution time, sample volume and adsorption time were optimized. With high enrichment factor of 100-fold, the detection limit of the proposed method is 7.9 ng L-1 for Au(III) with the relative standard deviation of 7.4% (c = 50 ng L-1, n = 7). In order to validate the accuracy of the proposed method, the Certified Reference Material of GBW07293 geological sample (platinpalladium ore) was analyzed, and the determined value was in good agreement with the certified value. The proposed II-MSPE-GFAAS method is simple, fast, selective, sensitive and has been successfully applied in the determination of trace Au in ore, sediment, environmental water and human urine samples with satisfactory results.

A Simple Apparatus for Fast Ion Exchange Separations

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K

1964-09-15

An apparatus suitable for very fast ion exchange group separations in radiochemistry has been elaborated. The apparatus which consists of a system of glass tubes with pistons driven by the same force, allows the exact adjustment of influent solutions to a long series of ion-exchange columns. The practical application of the apparatus to the simultaneous separation of six groups of trace elements in the neutron activation analysis of biological material is described.

A Simple Apparatus for Fast Ion Exchange Separations

International Nuclear Information System (INIS)

Samsahl, K.

1964-09-01

An apparatus suitable for very fast ion exchange group separations in radiochemistry has been elaborated. The apparatus which consists of a system of glass tubes with pistons driven by the same force, allows the exact adjustment of influent solutions to a long series of ion-exchange columns. The practical application of the apparatus to the simultaneous separation of six groups of trace elements in the neutron activation analysis of biological material is described

Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

NARCIS (Netherlands)

García-Munoz, M.; Hicks, N.; Voornveld, van R.; Classen, I.G.J.; Bilato, R.; Bobkov, V.; Brambilla, M.; Bruedgam, M.; Fahrbach, H. -U.; Igochine, V.; Jaemsae, S.; Maraschek, M.; Sassenberg, K.

2010-01-01

The phase-space of convective and diffusive fast-ion losses induced by shear Alfv´en eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfv´en eigenmodes (TAEs) and

Enhanced coupling of the fast wave to electrons through mode conversion to the ion hybrid wave

International Nuclear Information System (INIS)

Lashmore-Davies, C.N.; Fuchs, V.; Ram, A.K.; Bers, A.

1996-07-01

The mode conversion of the fast compressional Alfven wave to the ion hybrid wave is analyzed with particular reference to a plasma with two ion species present in approximately equal proportions. Two configurations are considered, the first referring to the usual resonance-cut-off case and the second to a cut-off-resonance-cut-off situation. The optimum conditions for maximising the mode converted energy are given. The second order fast wave equation is generalised to include the effect of the parallel electric field. Hence, all ion and electron loss mechanisms for the fast wave are incorporated, including mode conversion at the two-ion hybrid resonance. The significance of the approximate equality of the two ion species concentrations is that the mode converted ion hybrid wave is damped only by the electrons. The damping of the ion hybrid wave is described with the aid of the local dispersion relation and by means of a toroidal ray tracing code. In particular, the ray tracing calculation shows that the mode converted energy is totally absorbed by the electrons close to the two-ion hybrid resonance. The generalised fast wave equation is solved to determine how much energy is lost from the fast wave, incident from the low field side, before it encounters the two-ion hybrid resonance. For comparable concentrations of the two ion species, the mode converted power can be separated from the power directly absorbed by the ions and electrons from the fast wave. This allows the conditions to be ascertained under which strong electron heating through mode conversion dominates the direct dissipation of the fast wave. (UK)

Fast-extraction modulators for Los Alamos Scientific LaboratorY Proton Storage Ring

International Nuclear Information System (INIS)

Nunnally, W.C.; Hudgings, D.W.; Sarjeant, W.J.

1980-01-01

The development of a short-bunch mode fast-extraction modulator for the LASL proton storage ring has made necessary the design and development of a resonant transformer charging circuit and the design of a new FIB line circuit to provide bipolar pulse outputs with low prepulse, postpulse, and an optimum high-voltage switch environments. The systems are now being developed to operate reliably at the high-average powers required. The short-bunch mode fast-extraction modulator prototype is presently operating. The initial construction of the long-bunch mode fast-extraction modulator prototype is under way, with results expected within the year

Power deposition by neutral beam injected fast ions in field-reversed configurations

International Nuclear Information System (INIS)

Takahashi, Toshiki; Kato, Takayuki; Kondoh, Yoshiomi; Iwasawa, Naotaka

2004-01-01

The effects of Coulomb collisions on neutral beam (NB) injected fast ions into field-reversed configuration (FRC) plasmas are investigated by calculating the single particle orbits, where the ions are subject to the slowing-down and pitch-angle collisions. The Monte Carlo method is used for the pitch-angle scattering, and the friction term is added to the equation of motion to show the effects of the slowing-down collision, such as the deposited power profile. The calculation parameters used are relevant to the NB injection on the FRC injection experiment device [T. Asai, Y. Suzuki, T. Yoneda, F. Kodera, M. Okubo, and S. Goto, Phys. Plasmas 7, 2294 (2000)]. It is found that the dominant local power deposition occurs in the open field region between the X point and the mirror point because of a concentration of fast ions and a longer duration travel at the mirror reflection point. In the present calculation, the maximum deposited power to the FRC plasma is about 10% of the injected power. Although the pitch-angle scattering by Coulomb collision destroys the mirror confinement of NB injected fast ions, this effect is found to be negligible. The loss mechanism due to nonadiabatic fast ion motion, which is intrinsic in nonuniform FRC plasmas, has a much greater effect than the pitch-angle scattering by Coulomb collision

Simulation study on ion extraction from electron cyclotron resonance ion sources

Science.gov (United States)

Fu, S.; Kitagawa, A.; Yamada, S.

1994-04-01

In order to study beam optics of NIRS-ECR ion source used in the HIMAC project, the EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1D and 2D sheath theories are used, respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source are presented in this paper, exhibiting an agreement with the experiment results.

Second harmonic ion cylotron resonance heating by the fast magnetosonic wave on the PLT tokamak

International Nuclear Information System (INIS)

Thompson, H.R. Jr.

1984-01-01

Second harmonic ion cyclotron resonance heating by the fast magnetosonic wave, and the propagation of the fast wave from the fundamental of the ion cyclotron frequency to its second harmonic was investigated in a hydrogen plasma on the PLT tokamak. The theory of fast magnetosonic wave propagation was extended to include the effects of density gradients, plasma current, and impurity ion species. The damping of the fast wave at the second harmonic is calculated, where the theory has been extended to include the full radial dependence of the fast wave fields. Power deposition profiles and eigenmode Q's are calculated using this theory. The effects of the interaction between the ion Bernstein wave and the fast magnetosonic wave are calculated, and enhanced fast wave damping is predicted. The antenna loading is calculated including the effects of overlap of the fast wave eigenmodes. During the second harmonic heating experiments, the antenna loading was characterized as a function of the plasma parameters, and efficient coupling of the RF power to the plasma at high density was observed. At very low densities, fast wave eigenmodes were identified on PLT, and their Q's are measured. Eigenmodes with different toroidal directions of propagation were observed to exhibit large splitting in density due to the plasma current. Efficient bulk heating, with centrally peaked profiles, is observed at the second harmonic, and a tail, which decreases monotonically with energy, is observed on the ion distribution

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

International Nuclear Information System (INIS)

Wada, M.; Sasao, M.

1996-01-01

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

Ion beam extraction from a matrix ECR plasma source by discrete ion-focusing effect

DEFF Research Database (Denmark)

Stamate, Eugen; Draghici, Mihai

2010-01-01

-ECR plasma source [3] with transversal magnetic filter for electron temperature control. 12 ECR plasma cells are placed 7.5 cm apart on the top of a cubic chamber 40x40x40 cm3. Each cell can be controlled independently by tuning the injected microwave power. The discharge is operated at pressures below 1 m......Positive or negative ion beams extracted from plasma are used in a large variety of surface functionalization techniques such as implantation, etching, surface activation, passivation or oxidation. Of particular importance is the surface treatment of materials sensitive to direct plasma exposure...... due to high heath fluxes, the controllability of the ion incidence angle, and charge accumulation when treating insulating materials. Despite of a large variety of plasma sources available for ion beam extraction, there is a clear need for new extraction mechanisms that can make available ion beams...

Simulation of the CERN GTS-LHC ECR ion source extraction system with lead and argon ion beams

CERN Document Server

Toivanen, V; Küchler, D; Lombardi, A; Scrivens, R; Stafford-Haworth, J

2014-01-01

A comprehensive study of beam formation and beam transport has been initiated in order to improve the performance of the CERN heavy ion injector, Linac3. As part of this study, the ion beam extraction system of the CERN GTS-LHC 14.5 GHz Electron Cyclotron Resonance Ion Source (ECRIS) has been modelled with the ion optical code IBSimu. The simulations predict self-consistently the triangular and hollow beam structures which are often observed experimentally with ECRIS ion beams. The model is used to investigate the performance of the current extraction system and provides a basis for possible future improvements. In addition, the extraction simulation provides a more realistic representation of the initial beam properties for the beam transport simulations, which aim to identify the performance bottle necks along the Linac3 low energy beam transport. The results of beam extraction simulations with Pb and Ar ion beams from the GTS-LHC will be presented and compared with experimental observations.

Multiaperture ion beam extraction from gas-dynamic electron cyclotron resonance source of multicharged ions

International Nuclear Information System (INIS)

Sidorov, A.; Dorf, M.; Zorin, V.; Bokhanov, A.; Izotov, I.; Razin, S.; Skalyga, V.; Rossbach, J.; Spaedtke, P.; Balabaev, A.

2008-01-01

Electron cyclotron resonance ion source with quasi-gas-dynamic regime of plasma confinement (ReGIS), constructed at the Institute of Applied Physics, Russia, provides opportunities for extracting intense and high-brightness multicharged ion beams. Despite the short plasma lifetime in a magnetic trap of a ReGIS, the degree of multiple ionization may be significantly enhanced by the increase in power and frequency of the applied microwave radiation. The present work is focused on studying the intense beam quality of this source by the pepper-pot method. A single beamlet emittance measured by the pepper-pot method was found to be ∼70 π mm mrad, and the total extracted beam current obtained at 14 kV extraction voltage was ∼25 mA. The results of the numerical simulations of ion beam extraction are found to be in good agreement with experimental data

Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

DEFF Research Database (Denmark)

Nielsen, Stefan Kragh; Bindslev, Henrik; Porte, L.

2008-01-01

reported [Bindslev , Phys. Rev. Lett. 97, 205005 2006]. Here we extend the discussion of these results which were obtained at the TEXTOR tokamak. The fast ions are generated by neutral-beam injection and ion-cyclotron resonance heating. The CTS system uses 100-150 kW of 110-GHz gyrotron probing radiation......Fast ions created in the fusion processes will provide up to 70% of the heating in ITER. To optimize heating and current drive in magnetically confined plasmas insight into fast-ion dynamics is important. First measurements of such dynamics by collective Thomson scattering (CTS) were recently...... of the velocity distribution after turnoff of the ion heating. These results are in close agreement with numerical simulations....

Particle-in-cell studies of fast-ion slowing-down rates in cool tenuous magnetized plasma

Science.gov (United States)

Evans, Eugene S.; Cohen, Samuel A.; Welch, Dale R.

2018-04-01

We report on 3D-3V particle-in-cell simulations of fast-ion energy-loss rates in a cold, weakly-magnetized, weakly-coupled plasma where the electron gyroradius, ρe, is comparable to or less than the Debye length, λDe, and the fast-ion velocity exceeds the electron thermal velocity, a regime in which the electron response may be impeded. These simulations use explicit algorithms, spatially resolve ρe and λDe, and temporally resolve the electron cyclotron and plasma frequencies. For mono-energetic dilute fast ions with isotropic velocity distributions, these scaling studies of the slowing-down time, τs, versus fast-ion charge are in agreement with unmagnetized slowing-down theory; with an applied magnetic field, no consistent anisotropy between τs in the cross-field and field-parallel directions could be resolved. Scaling the fast-ion charge is confirmed as a viable way to reduce the required computational time for each simulation. The implications of these slowing down processes are described for one magnetic-confinement fusion concept, the small, advanced-fuel, field-reversed configuration device.

Alfvenic Instabilities and Fast Ion Transport in the DIII-D Tokamak

International Nuclear Information System (INIS)

Van Zeeland, M.; Heidbrink, W.; Nazikian, R.; Austin, M.; Berk, H.; Gorelenkov, N.; Holcomb, C.; Kramer, G.; Lohr, J.; Luo, Y.; Makowski, M.; McKee, G.; Petty, C.; Prater, R.; Solomon, W.; White, R.

2008-01-01

Neutral beam injection into reversed magnetic shear DIII-D plasmas produces a variety of Alfvenic activity including Toroidicity and Ellipticity induced Alfven Eigenmodes (TAE/EAE, respectively) and Reversed Shear Alfven Eigenmodes (RSAE) as well as their spatial coupling. These modes are typically studied during the discharge current ramp phase when incomplete current penetration results in a high central safety factor and strong drive due to multiple higher order resonances. During this same time period Fast-Ion D α (FIDA) spectroscopy shows that the central fast ion profile is flattened, the degree of which depends on the Alfven eigenmode amplitude. Interestingly, localized electron cyclotron heating (ECH) near the mode location stabilizes RSAE activity and results in significantly improved fast ion confinement relative to discharges with ECH deposition on axis. In these discharges, RSAE activity is suppressed when ECH is deposited near the radius of the shear reversal point and enhanced with deposition near the axis. To simulate the observed neutral beam ion redistribution, NOVA calculations of the 3D eigenmode structures are matched with experimental measurements and used in combination with the ORBIT guiding center following code. For fixed frequency eigenmodes, it is found that ORBIT calculations cannot explain the observed beam ion transport with experimentally measured mode amplitudes. Possible explanations are considered including recent simulation results incorporating eigenmodes with time dependent frequencies

Physics in the fast lane: rotors, fast ions and mobile fermions

International Nuclear Information System (INIS)

Price, D.L.; Saboungi, M.-L.

1996-09-01

Dynamic disorder in the high-temperature solid phases of the Zintl compounds CsPb and NaSn is characterized by. fast orientational motions of the polyanions and coupled motions of the cations Melting is characterized by slow translational motions of the centers of mass of the polyanions. The dynamic behavior of the ions is associated with dramatic increases in electrical conductivity characteristic of the behavior expected of a mixed conductor

Effects of Fast-Ion Injection on a Magnetized Sheath near a Floating Wall

International Nuclear Information System (INIS)

Li Jiajia; Hu Zhanghu; Song Yuanhong; Wang Younian

2013-01-01

A fully kinetic particle-in-cell/Monte Carlo model is employed to self-consistently study the effects of fast-ion injection on sheath potential and electric field profile in collisional magnetized plasma with a floating absorbing wall. The influences of the fast-ion injection velocity and density, the magnetic field and angle θ 0 formed by the magnetic field and the x-axis on the sheath potential and electric field are discussed in detail. Numerical results show that increasing fast-ion injection density or decreasing injection velocity can enhance the potential drop and electric field in the sheath. Also, increasing the magnetic field strength can weaken the loss of charged particles to the wall and thus decrease the potential and electric field in the sheath. The time evolution of ion flux and velocity distribution on the wall is found to be significantly affected by the magnetic field.

The role of space charge compensation for ion beam extraction and ion beam transport (invited)

International Nuclear Information System (INIS)

Spädtke, Peter

2014-01-01

Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation

On velocity space interrogation regions of fast-ion collective Thomson scattering at ITER

DEFF Research Database (Denmark)

Salewski, Mirko; Nielsen, Stefan Kragh; Bindslev, Henrik

2011-01-01

the collective scattering in well-defined regions in velocity space, here dubbed interrogation regions. Since the CTS instrument measures entire spectra of scattered radiation, many different interrogation regions are probed simultaneously. We here give analytic expressions for weight functions describing...... the interrogation regions, and we show typical interrogation regions of the proposed ITER CTS system. The backscattering system with receivers on the low-field side is sensitive to fast ions with pitch |p| = |v/v| ... scattering system with receivers on the high-field side would be sensitive to co- and counter-passing fast ions in narrow interrogation regions with pitch |p| > 0.6–0.8. Additionally, we use weight functions to reconstruct 2D fast-ion distribution functions, given two projected 1D velocity distribution...

Summary: Electron-cloud effects and fast-ion instability

International Nuclear Information System (INIS)

Furman, Miguel A.

2000-01-01

This is my summary of the talks on the electron-cloud effect and the fast-ion instability that were presented at the 8th ICFA Beam Dynamics Mini-Work shop on Two-Stream Instabilities in Particle Accelerators and Storage Rings,Santa Fe, NM, February 16--18, 2000

Conceptual design of the ITER fast-ion loss detector

International Nuclear Information System (INIS)

Garcia-Munoz, M.; Ayllon-Guerola, J.; Galdon, J.; Garcia Lopez, J.; Gonzalez-Martin, J.; Jimenez-Ramos, M. C.; Rodriguez-Ramos, M.; Rivero-Rodriguez, J. F.; Sanchis-Sanchez, L.; Kocan, M.; Bertalot, L.; Bonnet, Y.; Casal, N.; Giacomin, T.; Pinches, S. D.; Reichle, R.; Vayakis, G.; Veshchev, E.; Vorpahl, Ch.; Walsh, M.

2016-01-01

A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ∼5° might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ∼11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.

Conceptual design of the ITER fast-ion loss detector

Energy Technology Data Exchange (ETDEWEB)

Garcia-Munoz, M., E-mail: mgm@us.es; Ayllon-Guerola, J.; Galdon, J.; Garcia Lopez, J.; Gonzalez-Martin, J.; Jimenez-Ramos, M. C.; Rodriguez-Ramos, M.; Rivero-Rodriguez, J. F.; Sanchis-Sanchez, L. [Department of Atomic, Molecular and Nuclear Physics, University of Seville, 41012 Seville (Spain); CNA (Universidad de Sevilla-CSIC-J. Andalucía), Seville (Spain); Kocan, M.; Bertalot, L.; Bonnet, Y.; Casal, N.; Giacomin, T.; Pinches, S. D.; Reichle, R.; Vayakis, G.; Veshchev, E.; Vorpahl, Ch.; Walsh, M. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 Saint Paul-lez-Durance Cedex (France); and others

2016-11-15

A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ∼5° might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ∼11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.

Application of monocarboxylic acids for the extraction of metal ions-literature survey

International Nuclear Information System (INIS)

Brzozka, Z.; Rozycki, C.

1980-01-01

In the paper there is presented a literature review concerning the application of monocarboxylic acids for extraction of metal ions. The following problems are discussed: characteristic of monocarboxylic acids and their mixtures, the equilibria between the acid solution in organic solvent and aqueous phase, the mechanism of acid partition, complexes of carboxylic acids and metal ions in aqueous phase, mechanism of extraction by means of carboxylic acids as well as the problems concerning the extraction of individual metal ions. Data about the extraction of metal ions are presented in table. The 138 references are given. (author)

Metal negative ion beam extraction from a radio frequency ion source

Energy Technology Data Exchange (ETDEWEB)

Kanda, S.; Yamada, N.; Kasuya, T.; Romero, C. F. P.; Wada, M.

2015-04-08

A metal ion source of magnetron magnetic field geometry has been designed and operated with a Cu hollow target. Radio frequency power at 13.56 MHz is directly supplied to the hollow target to maintain plasma discharge and induce self-bias to the target for sputtering. The extraction of positive and negative Cu ion beams have been tested. The ion beam current ratio of Cu{sup +} to Ar{sup +} has reached up to 140% when Ar was used as the discharge support gas. Cu{sup −} ion beam was observed at 50 W RF discharge power and at a higher Ar gas pressure in the ion source. Improvement of poor RF power matching and suppression of electron current is indispensable for a stable Cu{sup −} ion beam production from the source.

Improving beam spectral and spatial quality by double-foil target in laser ion acceleration for ion-driven fast ignition

International Nuclear Information System (INIS)

Huang, Chenkun; Albright, Brian J.

2010-01-01

Mid-Z ion driven fast ignition inertial fusion requires ion beams of 100s of MeV energy and < 10% energy spread. An overdense run-scale foil target driven by a high intensity laser pulse can produce an ion beam that has attractive properties for this application. The Break Out Afterburner (BOA) is one laser-ion acceleration mechanism proposed to generate such beams, however the late stages of the BOA tend to produce too large of an energy spread. The spectral and spatial qualities of the beam quickly evolve as the ion beam and co-moving electrons continue to interact with the laser. Here we show how use of a second target foil placed behind a nm-scale foil can substantially reduce the temperature of the co-moving electrons and improve the ion beam energy spread. Particle-In-Cell simulations reveal the dynamics of the ion beam under control. Optimal conditions for improving the spectral and spatial spread of the ion beam is explored for current laser and target parameters, leading to generation of ion beams of energy 100s of MeV and 6% energy spread, a vital step for realizing ion-driven fast ignition.

Ionic liquids used in extraction and separation of metal ions

International Nuclear Information System (INIS)

Shen Xinghai; Xu Chao; Liu Xinqi; Chu Taiwei

2006-01-01

Ionic liquids as green solvents now have become a research hotspot in the field of separation of metal ions by solvent extraction. Experimental results of extraction of various metal ions with ionic liquids as solvents, including that of alkali metals, alkaline earths, transition metals rare earths and actinides are introduced. The extraction of uranium, plutonium and fission products that are involved in spent nuclear fuel reprocessing is also reviewed. The possible extraction mechanisms are discussed. Finally, the prospect of replacement of volatile and/or toxic organic solvents with environmentally benign ionic liquids for solvent extraction and the potency of applications of ionic liquids in solvent extraction are also commented. (authors)

Fusion yield rate recovery by escaping hot-spot fast ions in the neighboring fuel layer

Science.gov (United States)

Tang, Xian-Zhu; McDevitt, C. J.; Guo, Zehua; Berk, H. L.

2014-02-01

Free-streaming loss by fast ions can deplete the tail population in the hot spot of an inertial confinement fusion (ICF) target. Escaping fast ions in the neighboring fuel layer of a cryogenic target can produce a surplus of fast ions locally. In contrast to the Knudsen layer effect that reduces hot-spot fusion reactivity due to tail ion depletion, the inverse Knudsen layer effect increases fusion reactivity in the neighboring fuel layer. In the case of a burning ICF target in the presence of significant hydrodynamic mix which aggravates the Knudsen layer effect, the yield recovery largely compensates for the yield reduction. For mix-dominated sub-ignition targets, the yield reduction is the dominant process.

Electrical studies on silver based fast ion conducting glassy materials

International Nuclear Information System (INIS)

Rao, B. Appa; Kumar, E. Ramesh; Kumari, K. Rajani; Bhikshamaiah, G.

2014-01-01

Among all the available fast ion conductors, silver based glasses exhibit high conductivity. Further, glasses containing silver iodide enhances fast ion conducting behavior at room temperature. Glasses of various compositions of silver based fast ion conductors in the AgI−Ag 2 O−[(1−x)B 2 O 3 −xTeO 2 ] (x=0 to1 mol% in steps of 0.2) glassy system have been prepared by melt quenching method. The glassy nature of the compounds has been confirmed by X-ray diffraction. The electrical conductivity (AC) measurements have been carried out in the frequency range of 1 KHz–3MHz by Impedance Analyzer in the temperature range 303–423K. The DC conductivity measurements were also carried out in the temperature range 300–523K. From both AC and DC conductivity studies, it is found that the conductivity increases and activation energy decreases with increasing the concentration of TeO 2 as well as with temperature. The conductivity of the present glass system is found to be of the order of 10 −2 S/cm at room temperature. The ionic transport number of these glasses is found to be 0.999 indicating that these glasses can be used as electrolyte in batteries

Antenna design for fast ion collective Thomson scattering diagnostic for the international thermonuclear experimental reactor

DEFF Research Database (Denmark)

Leipold, Frank; Furtula, Vedran; Salewski, Mirko

2009-01-01

Fast ion physics will play an important role for the international thermonuclear experimental reactor (ITER), where confined alpha particles will affect and be affected by plasma dynamics and thereby have impacts on the overall confinement. A fast ion collective Thomson scattering (CTS) diagnostic...

Quantification of steroid conjugates using fast atom bombardment mass spectrometry

International Nuclear Information System (INIS)

Gaskell, S.J.

1990-01-01

Fast atom bombardment/mass spectrometry or liquid secondary ion mass spectrometry provides the capability for direct analysis of steroid conjugates (sulfates, glucuronides) without prior hydrolysis or derivatization. During the analysis of biologic extracts, limitations on the sensitivity of detection arise from the presence of co-extracted material which may suppress or obscure the analyte signal. A procedure is described for the quantitative determination of dehydroepiandrosterone sulfate in serum which achieved selective isolation of the analyte using immunoadsorption extraction and highly specific detection using tandem mass spectrometry. A stable isotope-labeled analog [( 2H2]dehydroepiandrosterone sulfate) was used as internal standard. Fast atom bombardment of dehydroepiandrosterone sulfate yielded abundant [M-H]- ions that fragmented following collisional activation to give HSO4-; m/z 97. During fast atom bombardment/tandem mass spectrometry of serum extracts, a scan of precursor ions fragmenting to give m/z 97 detected dehydroepiandrosterone sulfate and the [2H2]-labeled analog with a selectivity markedly superior to that observed using conventional mass spectrometry detection. Satisfactory agreement was observed between quantitative data obtained in this way and data obtained by gas chromatography/mass spectrometry of the heptafluorobutyrates of dehydroepiandrosterone sulfate and [2H2]dehydroepiandrosterone sulfate obtained by direct derivatization. 21 refs

Proceedings of the workshop on atomic physics with fast heavy-ion beams

International Nuclear Information System (INIS)

Kanter, E.P.; Minchinton, A.

1983-01-01

The Workshop on Atomic Physics with Fast Heavy-Ion Beams was held in the Physics Division, Argonne National Laboratory on January 20 and 21, 1983. The meeting brought together approx. 50 practitioners in the field of accelerator-based atomic physics. The workshop was held to focus attention on possible areas of atomic physics research which would benefit from use of the newest generation of accelerators designed to produce intense high-quality beams of fast heavy ions. Abstracts of individual paper were prepared separately for the data base

The virtual cathode: Key to the numerical simulation of negative ion extraction

International Nuclear Information System (INIS)

Becker, R.; Leung, K.N.; Kunkel, W.

1998-01-01

The simulation of volume produced negative ions from a plasma is by far more complicated than the extraction of positive ions, while in experiments the only difficulty seemes to be connected with the power of the electrons, which are extracted at the same time. The reason for this complication in simple minded simulations is the infinite space charge, which builds up in the turning point of the positive ions in the extraction aperture for the negative ions. Smearing out the energy of the positive ions seems to help, however, this is mostly not justified by experiments, showing a low ion energy, especially in the region between the magnetic filter and the extraction hole. This difficulty may be overcome by using experience from virtual cathode formation in magnetically focused, decelerated electron beams. The decelerated electrons behave similarly to the reflected positive ions and are forming a virtual cathode in the reflection zone. From the analysis of the electron deceleration experiment, a simple power law is deduced to describe the decreasing electron current by the local potential. In turn, this power law may also be applied to the positive ion current, resulting in simulations without space charge singularity, even in the case of monoenergetic ions. As a first step towards the numerical simulation of negative ion extraction, a linear model has been made, using this power law. The transition from a Boltzmann distribution for the plasma electrons to a truncated one for the extracted beam electrons is considered as well, parallel to Langmuir close-quote s treatment of a thermal diode for electrons. copyright 1998 American Institute of Physics

The Septum Magnet System of the New Fast Extraction Channel of the SPS at CERN

CERN Document Server

Balhan, B; Rizzo, A; Weterings, W

2004-01-01

In the Long Straight Section LSS4 of the Super Proton Synchrotron (SPS) at CERN, a new fast extraction system has been installed in order to extract the beam to ring 2 of the Large Hadron Collider (LHC) and the CERN Neutrino to Gran Sasso facility (CNGS). The system consists of horizontal closed orbit bumper magnets, extraction kicker magnets, enlarged aperture quadrupoles and six conventional DC electromagnetic septum magnets (MSE). A protection element (TPSG) has been placed immediately upstream of the first septum coil. The septum magnets and TPSG are mounted on a single mobile retractable support girder. The MSE septa are connected by a so-called plug-in system to a rigid water-cooled bus-bar, powered by water-cooled cables. The whole system is kept at the required vacuum pressure by ion pumps attached to separate pumping modules. In this note we present the design features and parameters of the MSE septum magnets, describe the function of the related main equipment elements, briefly report on the control...

On the meniscus formation and the negative hydrogen ion extraction from ITER neutral beam injection relevant ion source

Science.gov (United States)

Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Fantz, U.; Franzen, P.; Minea, T.

2014-10-01

The development of a large area (Asource,ITER = 0.9 × 2 m2) hydrogen negative ion (NI) source constitutes a crucial step in construction of the neutral beam injectors of the international fusion reactor ITER. To understand the plasma behaviour in the boundary layer close to the extraction system the 3D PIC MCC code ONIX is exploited. Direct cross checked analysis of the simulation and experimental results from the ITER-relevant BATMAN source testbed with a smaller area (Asource,BATMAN ≈ 0.32 × 0.59 m2) has been conducted for a low perveance beam, but for a full set of plasma parameters available. ONIX has been partially benchmarked by comparison to the results obtained using the commercial particle tracing code for positive ion extraction KOBRA3D. Very good agreement has been found in terms of meniscus position and its shape for simulations of different plasma densities. The influence of the initial plasma composition on the final meniscus structure was then investigated for NIs. As expected from the Child-Langmuir law, the results show that not only does the extraction potential play a crucial role on the meniscus formation, but also the initial plasma density and its electronegativity. For the given parameters, the calculated meniscus locates a few mm downstream of the plasma grid aperture provoking a direct NI extraction. Most of the surface produced NIs do not reach the plasma bulk, but move directly towards the extraction grid guided by the extraction field. Even for artificially increased electronegativity of the bulk plasma the extracted NI current from this region is low. This observation indicates a high relevance of the direct NI extraction. These calculations show that the extracted NI current from the bulk region is low even if a complete ion-ion plasma is assumed, meaning that direct extraction from surface produced ions should be present in order to obtain sufficiently high extracted NI current density. The calculated extracted currents, both ions

A lattice-gas model of the ion current across the solid interface: fast-ion conductor - intercalate

International Nuclear Information System (INIS)

Nachev, I.; Balkanski, M.

1994-12-01

The transport of Lithium ions across the material interface: fast-ion conducting glass - intercalate is simulated by a non-trivial lattice-gas model. The model takes explicitly into account the influence of the Coulomb correlations, the site-blocking effect and the boundary conditions on the ion kinetics. Potential device applications of the model are pointed out by computing the current density of Lithium ions for material parameters of the real interface: doped ternary borate glass - Indium Selenide, which constitute the electrolyte and the cathode, respectively, of a thin-film microbattery with improved performance. (author). 10 refs, 4 figs

Fast sodium ion conductivity in supertetrahedral phosphidosilicates.

Science.gov (United States)

Johrendt, Dirk; Haffner, Arthur; Hatz, Anna Katharina; Moudrakovski, Igor; Lotsch, Bettina Valeska

2018-04-03

Fast sodium ion conductors are key components of sodium-based all-solid-state batteries which hold promise as safe systems for large-scale storage of electrical power. Here, we report the synthesis, crystal structure determination and Na+ ion conductivities of six new sodium ion conductors, the phosphidosilicates Na19Si13P25, Na23Si19P33, Na23Si28P45, Na23Si37P57, LT-NaSi2P3 and HT-NaSi2P3, which are entirely based on earth-abundant elements. The new structures exhibit SiP4 tetrahedra assembling interpenetrating networks of T3 to T5 supertetrahedral clusters which can be hierarchically assigned to sphalerite- or diamond-type structures. 23Na solid-state NMR spectra and geometrical pathway analysis indicate Na+ ion mobility between the supertetrahedral cluster networks. Electrochemical impedance spectroscopy revealed Na+ ion conductivities up to σ (Na+) = 4 ∙ 10-4 Scm-1 with an activation energy of Ea = 0.25 eV in HT-NaSi2P3 at 25 °C. The conductivities increase with the size of the supertetrahedral clusters due to the dilution of Na+ ions as the charge density of the anionic supertetrahedral networks decreases. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiple-electron processes in fast ion-atom collisions

International Nuclear Information System (INIS)

Schlachter, A.S.

1989-03-01

Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multiple-electron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented. 20 refs., 15 figs

Alfv?nic Instabilities and Fast Ion Transport in the DIII-D Tokamak

Energy Technology Data Exchange (ETDEWEB)

Van Zeeland, M; Heidbrink, W; Nazikian, R; Austin, M; Berk, H; Gorelenkov, N; Holcomb, C; Kramer, G; Lohr, J; Luo, Y; Makowski, M; McKee, G; Petty, C; Prater, R; Solomon, W; White, R

2008-10-14

Neutral beam injection into reversed magnetic shear DIII-D plasmas produces a variety of Alfvenic activity including Toroidicity and Ellipticity induced Alfven Eigenmodes (TAE/EAE, respectively) and Reversed Shear Alfven Eigenmodes (RSAE) as well as their spatial coupling. These modes are typically studied during the discharge current ramp phase when incomplete current penetration results in a high central safety factor and strong drive due to multiple higher order resonances. During this same time period Fast-Ion D{sub {alpha}} (FIDA) spectroscopy shows that the central fast ion profile is flattened, the degree of which depends on the Alfven eigenmode amplitude. Interestingly, localized electron cyclotron heating (ECH) near the mode location stabilizes RSAE activity and results in significantly improved fast ion confinement relative to discharges with ECH deposition on axis. In these discharges, RSAE activity is suppressed when ECH is deposited near the radius of the shear reversal point and enhanced with deposition near the axis. To simulate the observed neutral beam ion redistribution, NOVA calculations of the 3D eigenmode structures are matched with experimental measurements and used in combination with the ORBIT guiding center following code. For fixed frequency eigenmodes, it is found that ORBIT calculations cannot explain the observed beam ion transport with experimentally measured mode amplitudes. Possible explanations are considered including recent simulation results incorporating eigenmodes with time dependent frequencies.

Velocity space resolved absolute measurement of fast ion losses induced by a tearing mode in the ASDEX Upgrade tokamak

Science.gov (United States)

Galdon-Quiroga, J.; Garcia-Munoz, M.; Sanchis-Sanchez, L.; Mantsinen, M.; Fietz, S.; Igochine, V.; Maraschek, M.; Rodriguez-Ramos, M.; Sieglin, B.; Snicker, A.; Tardini, G.; Vezinet, D.; Weiland, M.; Eriksson, L. G.; The ASDEX Upgrade Team; The EUROfusion MST1 Team

2018-03-01

Absolute flux of fast ion losses induced by tearing modes have been measured by means of fast ion loss detectors (FILD) for the first time in RF heated plasmas in the ASDEX Upgrade tokamak. Up to 30 MW m-2 of fast ion losses are measured by FILD at 5 cm from the separatrix, consistent with infra-red camera measurements, with energies in the range of 250-500 keV and pitch angles corresponding to large trapped orbits. A resonant interaction between the fast ions in the high energy tail of the ICRF distribution and a m/n  =  5/4 tearing mode leads to enhanced fast ion losses. Around 9.3 +/- 0.7 % of the fast ion losses are found to be coherent with the mode and scale linearly with its amplitude, indicating the convective nature of the transport mechanism. Simulations have been carried out to estimate the contribution of the prompt losses. A good agreement is found between the simulated and the measured velocity space of the losses. The velocity space resonances that may be responsible for the enhanced fast ion losses are identified.

BRIEF COMMUNICATION: Fast-ion redistribution due to sawtooth crash in the TEXTOR tokamak measured by collective Thomson scattering

Science.gov (United States)

Nielsen, S. K.; Bindslev, H.; Salewski, M.; Bürger, A.; Delabie, E.; Furtula, V.; Kantor, M.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K.; Moseev, D.; Oosterbeek, J. W.; Stejner, M.; Westerhof, E.; Woskov, P.; TEXTOR Team

2010-09-01

Here we present collective Thomson scattering measurements of 1D fast-ion velocity distribution functions in neutral beam heated TEXTOR plasmas with sawtooth oscillations. Up to 50% of the fast ions in the centre are redistributed as a consequence of a sawtooth crash. We resolve various directions to the magnetic field. The fast-ion distribution is found to be anisotropic as expected. For a resolved angle of 39° to the magnetic field we find a drop in the fast-ion distribution of 20-40%. For a resolved angle of 83° to the magnetic field the drop is no larger than 20%.

FIFPC, a fast ion Fokker--Planck code

International Nuclear Information System (INIS)

Fowler, R.H.; Callen, J.D.; Rome, J.A.; Smith, J.

1976-07-01

A computer code is described which solves the Fokker--Planck equation for the velocity space distribution of fast ions injected into a tokamak plasma. The numerical techniques are described and use of the code is outlined. The program is written in FORTRAN IV and is modularized in order to provide greater flexibility to the user. A program listing is provided and the results of sample cases are presented

Auger processes in tracks of fast multicharged ions

International Nuclear Information System (INIS)

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

1992-01-01

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

Self-consistent Study of Fast Particle Redistribution by Alfven Eigenmodes During Ion Cyclotron Resonance Heating

International Nuclear Information System (INIS)

Bergkvist, T.; Hellsten, T.; Johnson, T.

2006-01-01

Alfven eigenmodes (AEs) excited by fusion born α particles can degrade the heating efficiency of a burning plasma and throw out αs. To experimentally study the effects of excitation of AEs and the redistribution of the fast ions, ion cyclotron resonance heating (ICRH) is often used. The distribution function of thermonuclear αs in a reactor is expected to be isotropic and constantly renewed through DT reactions. The distribution function of cyclotron heated ions is strongly anisotropic, and the ICRH do not only renew the distribution function but also provide a strong decorrelation mechanism between the fast ions and the AE. Because of the sensitivity of the AE dynamics on the details of the distribution function, the location of the resonance surfaces in phase space and the extent of the overlapping resonant regions for different AEs, a self-consistent treatment of the AE excitation and the ICRH is necessary. Interactions of fast ions with AEs during ICRH has been implemented in the SELFO code. Simulations are in good agreement with the experimentally observer pitch-fork splitting and rapid damping of the AE as ICRH is turned off. The redistribution of fast ions have been studied in the presence of several driven AEs. (author)

Development of alternate extractant systems for fast reactor fuel cycle

International Nuclear Information System (INIS)

Vasudeva Rao, P.R.; Suresh, A.; Venkatesan, K.A.; Srinivasan, T.G.; Raj, Baldev

2007-01-01

Due to the limitations of TBP in processing of high burn-up, Pu-rich fast reactor fuels, there is a need to develop alternate extractants for fast reactor fuel processing. In this context, our Centre has been examining the suitability of alternate tri-alkyl phosphates. Third phase formation in the extraction of Th(IV) by TBP, tri-n-amyl phosphate (TAP) and tri-2-methyl-butyl phosphate (T2MBP) from nitric acid media has been investigated under various conditions to derive conclusions on their application for extraction of Pu at macro levels. The chemical and radiolytic degradation of tri-n-amyl-phosphate (TAP) diluted in normal paraffin hydrocarbon (NPH) in the presence of nitric acid has been investigated by the measurement of plutonium retention in organic phase. The potential application of room temperature ionic liquids (RTILs) for reprocessing of spent nuclear fuel has been explored. Extraction of uranium (VI) and palladium (II) from nitric acid medium by commercially available RTIL and tri-n-butyl phosphate solution in RTIL have been studied and the feasibility of electrodeposition of uranium as uranium oxide (UO 2 ) and palladium (II) as metallic palladium from the loaded organic phase have been demonstrated. This paper describes results of the above studies and discusses the suitability of the systems for fast reactor fuel reprocessing. (authors)

Investigation of extraction of actinyl ions with inorganic ligands Pt. 1

International Nuclear Information System (INIS)

Fucks, L.; Lis, S.; Fidelis, I.

1979-01-01

Extraction coefficients (D) of hexavalent actinide ions have been determined by extraction chromatography, utilizing the selectivity of the TBP - HNO 3 system towards oxidation states. Plots logD against nitric acid concentration and logD against the atomic number of actinides show the decrease of extractability with Z, and a distinctly smaller difference between the extractability of uranyl and neptunyl than that of neptunyl and plutonyl ions. This latter fact is connected with the double-double effect. (A.L.)

Light ion source studies with a magnetically insulated extraction diode

International Nuclear Information System (INIS)

Struckman, C.K.

1992-01-01

Light ion sources are currently being studied to assess their ability to drive an inertial confinement fusion reactor. The author has produced a high purity, 1MV, 300A/cm 2 lithium beam using a 200cm 2 extraction geometry, magnetically insulated ion diode. The lithium source was an AC glow discharge cleaned, LiF/Al film active anode. The active anode plasma was formed after 50KA of current was shunted through the anode film for 20ns. The stoichiometry of the resulting ion beam was 65% Li + , 20% Al +2 , and 15% H + . Without the glow discharge cleaning, the ion beam was over 55% hydrogen and only 20% Li + . At the time of the diode's design, extraction diodes were producing poor ion beams: their current efficiency was only 60-70%, and their extracted ion current was radially nonuniform. This diode was the first high efficiency extraction diode, and produced over 200KA of ions with 80-90% ion current efficiency. In addition, by varying the tilt of the applied magnetic field, it was possible to show that the ion current density could be made independent of radius. Since the author was unable to make a Li + beam with a passive anode, he installed an active anode that used an external current to vaporize a thin metal film on the anode surface. Poor beam purity was the most serious problem with active anodes. In order to remove impurities, especially the hydrogen contamination, the author cleaned the anodes with a glow discharge. Al film anodes were cleaned with a 110mA, 33W DC glow discharge, and the LiF/Al film anodes were cleaned with an equivalent AC discharge. The results obtained and a model for the mechanism behind the cleaning process are throughly discussed

Advanced light ion source extraction system for a new electron cyclotron resonance ion source geometry at Saclay

Energy Technology Data Exchange (ETDEWEB)

Delferriere, O.; Gobin, R.; Harrault, F.; Nyckees, S.; Sauce, Y.; Tuske, O. [Commissariat a l' Energie Atomique, CEA/Saclay, DSM/IRFU, 91191 Gif/Yvette (France)

2012-02-15

One of the main goal of intense light ion injector projects such as IPHI, IFMIF, or SPIRAL2, is to produce high current beams while keeping transverse emittance as low as possible. To prevent emittance growth induced in a dual solenoid low energy transfer line, its length has to be minimized. This can be performed with the advanced light ion source extraction system concept that we are developing: a new ECR 2.45 GHz type ion source based on the use of an additional low energy beam transport (LEBT) short length solenoid close to the extraction aperture to create the resonance in the plasma chamber. The geometry of the source has been considerably modified to allow easy maintenance of each component and to save space in front of the extraction. The source aims to be very flexible and to be able to extract high current ion beams at energy up to 100 kV. A specific experimental setup for this source is under installation on the BETSI test bench, to compare its performances with sources developed up to now in the laboratory, such as SILHI, IFMIF, or SPIRAL2 ECR sources. This original extraction source concept is presented, as well as electromagnetic simulations with OPERA-2D code. Ion beam extraction in space charge compensation regime with AXCEL, and beam dynamics simulation with SOLMAXP codes show the beam quality improvement at the end of the LEBT.

Electroless Formation of Hybrid Lithium Anodes for Fast Interfacial Ion Transport

KAUST Repository

Choudhury, Snehashis; Tu, Zhengyuan; Stalin, Sanjuna; Vu, Duylinh; Fawole, Kristen; Gunceler, Deniz; Sundararaman, Ravishankar; Archer, Lynden A.

2017-01-01

Rechargeable batteries based on metallic anodes are of interest for fundamental and application-focused studies of chemical and physical kinetics of liquids at solid interfaces. Approaches that allow facile creation of uniform coatings on these metals to prevent physical contact with liquid electrolytes, while enabling fast ion transport, are essential to address chemical instability of the anodes. Here, we report a simple electroless ion-exchange chemistry for creating coatings of indium on lithium. By means of joint density functional theory and interfacial characterization experiments, we show that In coatings stabilize Li by multiple processes, including exceptionally fast surface diffusion of lithium ions and high chemical resistance to liquid electrolytes. Indium coatings also undergo reversible alloying reactions with lithium ions, facilitating design of high-capacity hybrid In-Li anodes that use both alloying and plating approaches for charge storage. By means of direct visualization, we further show that the coatings enable remarkably compact and uniform electrodeposition. The resultant In-Li anodes are shown to exhibit minimal capacity fade in extended galvanostatic cycling when paired with commercial-grade cathodes.

Electroless Formation of Hybrid Lithium Anodes for Fast Interfacial Ion Transport

KAUST Repository

Choudhury, Snehashis

2017-08-17

Rechargeable batteries based on metallic anodes are of interest for fundamental and application-focused studies of chemical and physical kinetics of liquids at solid interfaces. Approaches that allow facile creation of uniform coatings on these metals to prevent physical contact with liquid electrolytes, while enabling fast ion transport, are essential to address chemical instability of the anodes. Here, we report a simple electroless ion-exchange chemistry for creating coatings of indium on lithium. By means of joint density functional theory and interfacial characterization experiments, we show that In coatings stabilize Li by multiple processes, including exceptionally fast surface diffusion of lithium ions and high chemical resistance to liquid electrolytes. Indium coatings also undergo reversible alloying reactions with lithium ions, facilitating design of high-capacity hybrid In-Li anodes that use both alloying and plating approaches for charge storage. By means of direct visualization, we further show that the coatings enable remarkably compact and uniform electrodeposition. The resultant In-Li anodes are shown to exhibit minimal capacity fade in extended galvanostatic cycling when paired with commercial-grade cathodes.

Effects of fast monoenergetic electrons on the ion dynamics near the cathode in a pulsed direct current plasma sheath

International Nuclear Information System (INIS)

Sharifian, M.; Shokri, B.

2008-01-01

A detailed one-dimensional simulation of the ion dynamics of the plasma sheath near a substrate (cathode) in the presence of fast monoenergetic electrons has been carried out in this article. The sheath evolution is investigated by using a fluid model assuming that the ions, plasma electrons and monoenergetic, fast electrons act as three fluids (fluid approach). The effect of the density of fast electrons on the ion density, ion velocity, and ion energy near the cathode and the evolution of the sheath boundary in front of the cathode are separately explored. Also, the variation of the ion velocity and ion density at the vicinity of the cathode as a function of time is investigated in the absence and presence of the electron beam. Results indicate that the presence of fast electrons in the sheath causes significant change in the sheath thickness and therefore basically changes the ion velocity, ion density, and ion impact energy on the cathode compared to the absence of the electron beam case

Physics with fast molecular-ion beams. Proceedings of workshop held at Argonne National Laboratory, August 20-21, 1979

International Nuclear Information System (INIS)

Gemmell, D.S.

1979-01-01

The Workshop on Physics with Fast Molecular-Ion Beams was held in the Physics Division, Argonne National Laboratory on August 20 and 21, 1979. The meeting brought together representatives from several groups studying the interactions of fast (MeV) molecular-ion beams with matter. By keeping the Workshop program sharply focussed on current work related to the interactions of fast molecular ions, it was made possible for the participants to engage in vigorous and detailed discussions concerning such specialized topics as molecular-ion dissociation and transmission, wake effects, ionic charge states, cluster stopping powers, beam-foil spectroscopy, electron-emissions studies with molecular-ion beams, and molecular-ion structure determinations

Design of extraction system in BRing at HIAF

Science.gov (United States)

Ruan, Shuang; Yang, Jiancheng; Zhang, Jinquan; Shen, Guodong; Ren, Hang; Liu, Jie; Shangguan, Jingbing; Zhang, Xiaoying; Zhang, Jingjing; Mao, Lijun; Sheng, Lina; Yin, Dayu; Wang, Geng; Wu, Bo; Yao, Liping; Tang, Meitang; Cai, Fucheng; Chen, Xiaoqiang

2018-06-01

The Booster Ring (BRing), which is the key part of HIAF (High Intensity heavy ion Accelerator Facility) complex at IMP (Institute of Modern Physics, Chinese Academy of Sciences), can provide uranium (A / q = 7) beam with a wide extraction energy range of 200-800 MeV/u. To fulfill a flexible beam extraction for multi-purpose experiments, both fast and slow extraction systems will be accommodated in the BRing. The fast extraction system is used for extracting short bunched beam horizontally in single-turn. The slow extraction system is used to provide quasi-continuous beam by the third order resonance and RF-knockout scheme. To achieve a compact structure, the two extraction systems are designed to share the same extraction channel. The general design of the fast and slow extraction systems and simulation results are discussed in this paper.

Effect of feedback and noise on fast ion instability

International Nuclear Information System (INIS)

Chao, A.W.; Stupakov, G.V.

1997-07-01

One can use a feedback system to suppress the fast ion instability. However, the feedback noise (and also other sources of noise in the machine) continuously excites the transient oscillations in the electron beam that are amplified through the electron interaction with the ions. We calculate the equilibrium level of these oscillations under the influence of the feedback and show how they grow exponentially from the head to the tail of the bunch train in a linear theory. Nonlinear saturation effects are assume negligible

Delta-electron emission in fast heavy ion atom collisions

International Nuclear Information System (INIS)

Schmidt-Boecking, H.; Ramm, U.; Berg, H.; Kelbch, C.; Feng Jiazhen; Hagmann, S.; Kraft, G.; Ullrich, J.

1991-01-01

The δ-electron emission processes occuring in fast heavy ion atom collisons are explained qualitatively. The different spectral structures of electron emission arising from either the target or the projectile are explained in terms of simple models of the kinetics of momentum transfer induced by the COULOMB forces. In collisions of very heavy ions with matter, high nuclear COULOMB forces are created. These forces lead to a strong polarization of the electronic states of the participated electrons. The effects of this polarization are discussed. (orig.)

First results from negative ion beam extraction in ROBIN in surface mode

Science.gov (United States)

Pandya, Kaushal; Gahlaut, Agrajit; Yadav, Ratnakar K.; Bhuyan, Manas; Bandyopadhyay, Mainak; Das, B. K.; Bharathi, P.; Vupugalla, Mahesh; Parmar, K. G.; Tyagi, Himanshu; Patel, Kartik; Bhagora, Jignesh; Mistri, Hiren; Prajapati, Bhavesh; Pandey, Ravi; Chakraborty, Arun. K.

2017-08-01

ROBIN, the first step in the Indian R&D program on negative ion beams has reached an important milestone, with the production of negative ions in the surface conversion mode through Cesium (Cs) vapor injection into the source. In the present set-up, negative hydrogen ion beam extraction is effected through an extraction area of ˜73.38 cm2 (146 apertures of 8mm diameter). The three grid electrostatic accelerator system of ROBIN is fed by high voltage DC power supplies (Extraction Power Supply System: 11kV, 35A and Acceleration Power Supply System: 35kV, 15A). Though, a considerable reduction of co-extracted electron current is usually observed during surface mode operation, in order to increase the negative ion current, various other parameters such as plasma grid temperature, plasma grid bias, extraction to acceleration voltage ratio, impurity control and Cs recycling need to be optimized. In the present experiments, to control and to understand the impurity behavior, a Cryopump (14,000 l/s for Hydrogen) is installed along with a Residual Gas Analyzer (RGA). To characterize the source plasma, two sets of Langmuir probes are inserted through the diagnostic flange ports available at the extraction plane. To characterize the beam properties, thermal differential calorimeter, Doppler Shift Spectroscopy and electrical current measurements are implemented in ROBIN. In the present set up, all the negative ion beam extraction experiments have been performed by varying different experimental parameters e.g. RF power (30-70 kW), source operational pressure (0.3 - 0.6Pa), plasma grid bias voltage, extraction & acceleration voltage combination etc. The experiments in surface mode operation is resulted a reduction of co-extracted electron current having electron to ion ratio (e/i) ˜2 whereas the extracted negative ion current density was increased. However, further increase in negative ion current density is expected to be improved after a systematic optimization of the

ITER Plasma at Ion Cyclotron Frequency Domain: The Fusion Alpha Particles Diagnostics Based on the Stimulated Raman Scattering of Fast Magnetosonic Wave off High Harmonic Ion Bernstein Modes

Science.gov (United States)

Stefan, V. Alexander

2014-10-01

A novel method for alpha particle diagnostics is proposed. The theory of stimulated Raman scattering, SRS, of the fast wave and ion Bernstein mode, IBM, turbulence in multi-ion species plasmas, (Stefan University Press, La Jolla, CA, 2008). is utilized for the diagnostics of fast ions, (4)He (+2), in ITER plasmas. Nonlinear Landau damping of the IBM on fast ions near the plasma edge leads to the space-time changes in the turbulence level, (inverse alpha particle channeling). The space-time monitoring of the IBM turbulence via the SRS techniques may prove efficient for the real time study of the fast ion velocity distribution function, spatial distribution, and transport. Supported by Nikola Tesla Labs., La Jolla, CA 92037.

Fast-ion diffusion measurements from radial triton burn up studies

International Nuclear Information System (INIS)

McCauley, J.S.; Budny, R.; McCune, D.; Strachan, J.D.

1993-08-01

A fast-ion diffusion coefficient of 0.1 ± 0.1 m 2 s -1 has been deduced from the triton burnup neutron emission profile measured by a collimated array of helium-4 spectrometers. The experiment was performed with high-power deuterium discharges produced by Princeton University's Tokamak Fusion Test Reactor (TFTR). The fast ions monitored were the 1.0 MeV tritons produced from the d(d,t)p. These tritons ''burn up'' with deuterons and emit a 14 MeV neutron by the d(t,α)n reaction. The ratio of the measured to calculated DT yield is typically 70%. The measured DT profile width is comparable to that predicted by the TRANSP transport code during neutral beam heating and narrower after the beam heating ended

Extraction of low-energy negative oxygen ions for thin film formation

International Nuclear Information System (INIS)

Vasquez, M. Jr.; Sasaki, D.; Kasuya, T.; Wada, M.; Maeno, S.

2011-01-01

Coextraction of low-energy positive and negative ions were performed using a plasma sputter-type ion source system driven by a 13.56 MHz radio frequency (rf) power. Titanium (Ti) atoms were sputtered out from a target and the sputtered neutrals were postionized in oxygen/argon (O 2 /Ar) plasma prior to extraction. The negative O ions were surface-produced and self-extracted. Mass spectral analyses of the extracted ion beams revealed the dependence of the ion current on the incident rf power, induced target bias and O 2 /Ar partial pressure ratio. Ti + current was found to be dependent on Ar + current and reached a saturation value with increasing O 2 partial pressure while the O - current showed a peak current at around 1:9 O 2 /Ar partial pressure ratio. Ti + current was several orders of magnitude higher than that of the O - current.

Progress and prospects of ion-driven fast ignition

International Nuclear Information System (INIS)

Fernandez, Juan C.; Albright, Brian J.; Flippo, Kirk A.; Gautier, D. Cort; Hegelich, Bjoern M.; Schmitt, Mark J.; Yin Lin; Honrubia, J.J.; Temporal, M.

2009-01-01

Fusion fast ignition (FI) initiated by laser-driven ion beams is a promising concept examined in this paper. FI based on a beam of quasi-monoenergetic ions (protons or heavier ions) has the advantage of a more localized energy deposition, which minimizes the required total beam energy, bringing it close to the ∼10 kJ minimum required for fuel densities ∼500 g cm -3 . High-current, laser-driven ion beams are most promising for this purpose. Because they are born neutralized in picosecond timescales, these beams may deliver the power density required to ignite the compressed DT fuel, ∼10 kJ/10 ps into a spot 20 μm in diameter. Our modelling of ion-based FI include high fusion gain targets and a proof of principle experiment. That modelling indicates the concept is feasible, and provides confirmation of our understanding of the operative physics, a firmer foundation for the requirements, and a better understanding of the optimization trade space. An important benefit of the scheme is that such a high-energy, quasi-monoenergetic ignitor beam could be generated far from the capsule (≥1 cm away), eliminating the need for a reentrant cone in the capsule to protect the ion-generation laser target, a tremendous practical benefit. This paper summarizes the ion-based FI concept, the integrated ion-driven FI modelling, the requirements on the ignitor beam derived from that modelling, and the progress in developing a suitable laser-driven ignitor ion beam.

Extractive liquid-liquid spectrophotometric procedure for the determination of thiocyanate ions employing the ion pair reagent amiloride monohydrochloride

International Nuclear Information System (INIS)

Bashammakh, A.S.; Bahaffi, S.O.; Al-Sibaai, A.A.; Al-Wael, H.O.; El-Shahawi, M.S.

2007-01-01

An accurate, inexpensive and less laborious liquid-liquid extractive spectrophotometric procedure for the determination of thiocyanate ions in aqueous media has been developed. The method has been based upon the formation of a yellow colored complex ion associate of the ion-pairing reagent 1-(3, 5-diamino-6-chloropyrazinecarboxyl) guanidine hydrochloride monohydrate, namely amiloride hydrochloride, DPG + .Cl - and the thiocyanate ions in aqueous media containing HNO 3 (0.5 mol L -1 ) and subsequent extraction with 4-methyl-2-pentanone. The absorption electronic spectrum of the ion associate showed one well-defined peak at λ max 366 nm. The stoichiometric mole ratio of DPG + .Cl - to the thiocyanate ions is 1:1.The effective molar absorptivity (ε) of the ion associate at λ max 366 nm is 1.1 ± 0.1 x 10 4 L mol -1 cm -1 . The extraction constants (K d , K ex , and β) enabled a simple and convenient use of the developed binary ion associate for the extractive spectrophotometric determination of traces of thiocyanate ions in the aqueous media. Beer's law and Ringbom's plots are obeyed in the concentration range 0.05-10 and 0.1-7 μg mL -1 of the thiocyanate ions, respectively with a relative standard deviation of ±2.3%. The calculated lower limits of detection (LOD) and quantitation (LOQ) of the developed procedure for the thiocyanate ions were found equal to 0.02 and 0.066 μg mL -1 , respectively. The developed method has been applied for the determination of trace amounts of thicyanate ions in tap-, waste- and natural water samples and compared successfully with the reported methods at the 95% confidence level. The proposed method was also applied successfully for the determination of thiocyanate ions in saliva samples

Vitamin D-metabolites from human plasma and mass spectrometric analysis by fast heavy ion induced desorption

Energy Technology Data Exchange (ETDEWEB)

Fohlman, J; Peterson, P A [Uppsala Univ. (Sweden). Dept. of Cell Research; Kamensky, I; Hakansson, P; Sundqvist, B [Tandemacceleratorlaboratoriet, Uppsala (Sweden)

1982-07-01

D-vitamin metabolites have been isolated from human serum employing chromatographic techniques. The serum carrier protein for vitamin D (DBP) was first isolated by immunosorbent chromatography. Lipid ligands associated with DBP were then extracted with hexane and separated by high pressure liquid chromatography (HPLC). Detection of vitamin D metabolites by their absorbance of ultraviolet light is not sufficiently sensitive to monitor all vitamin D derivatives from a few millilitres of serum. Therefore, further analyses are necessary to quantitative these compounds. We have begun to develop a mass spectrometric method to achieve a reliable, quantitative procedure. As a first step towards this goal a number of pure samples of vitamin D compounds have been studied in a time-of-flight mass spectrometer based on fast heavy ion induced desorption. All vitamin D compounds examined could be detected and identified by their molecular ion and fragment spectra.

Vitamin D-metabolites from human plasma and mass spectrometric analysis by fast heavy ion induced desorption

International Nuclear Information System (INIS)

Fohlman, J.; Peterson, P.A.

1982-01-01

D-vitamin metabolites have been isolated from human serum employing chromatographic techniques. The serum carrier protein for vitamin D (DBP) was first isolated by immunosorbent chromatography. Lipid ligands associated with DBP were then extracted with hexane and separated by high pressure liquid chromatography (HPLC). Detection of vitamin D metabolites by their absorbance of ultraviolet light is not sufficiently sensitive to monitor all vitamin D derivatives from a few millilitres of serum. Therefore, further analyses are necessary to quantitative these compounds. We have begun to develop a mass spectrometric method to achieve a reliable, quantitative procedure. As a first step towards this goal a number of pure samples of vitamin D compounds have been studied in a time-of-flight mass spectrometer based on fast heavy ion induced desorption. All vitamin D compounds examined could be detected and identified by their molecular ion and fragment spectra. (orig.)

Extraction of Co ions from ion-exchange resin by supercritical carbon dioxide

International Nuclear Information System (INIS)

Ju, Min Su; Koh, Moon Sung; Yang, Sung Woo; Park, Kwang Heon; Kim, Hak Won; Kim, Hong Doo

2005-01-01

There are a number of liquid treatment processes for eliminating radioactive ionic contaminants in nuclear facilities. One of the most common treatment methods for aqueous streams is the use of ion exchange, which is a well-developed technique that has been employed for many years in the nuclear industry. More specifically speaking, systems that ion exchange method is applied to in nuclear power plants are liquid radioactive waste treatment system, chemical and volume control system, steam generator blowdown treatment system, and service water supply system. During the operation of nuclear power plants, radioactive contaminants such as Co-60, Mn-54, Fe-59 and Cs-137 are contained in liquid radioactive wastes. And the wastes containing small amount of uranium are generated in nuclear fuel cycle facilities. To treat the liquid radioactive waste, we usually install ion exchangers rather than evaporators due to their simplicity and effectiveness, and this trend is increasing. However, the ion exchange process produces large volume of spent organic resin, and has some problems of radiation damage and thermal instability. And the reuse of the resin is limited due to the degradation of ion-exchanging ability. For this reason, were should consider a better method to expand the lifetime of the resin or to reduce the volume of radioactive resin wastes by extracting radioactive contaminants located in the resin. Supercritical fluid CO 2 has many good points as a process solvent that include low viscosity, negligible surface tension, and variable selectivity. And supercritical fluids have physical properties of both liquid and gas such as good penetration with a high dissolution capability. Supercritical fluids have been widely used in extraction, purification, and recovery processes. A number of workers applied supercritical CO 2 solvent for cleaning of precision devices and waste treatments. Since supercritical CO 2 has its mild critical point at 31 and 73.8bar as .deg. C

Fast Extraction Kicker for the Accelerator Test Facility

International Nuclear Information System (INIS)

De Santis, Stefano; Urakawa, Junji; Naito, Takashi

2007-01-01

We present the results of a study for the design of a fast extraction kicker to be installed in the Accelerator Test Facility ring at KEK. This activity is carried on in the framework of the ATF2 project, which will be built on the KEK Tsukuba campus as an extension of the existing ATF, taking advantage of the worlds smallest normalized emittance achieved there. ATF2's primary goal is to operate as a test facility and establish the hardware and beam handling technologies envisaged for the International Linear Collider. In particular, the fast extraction kicker object of the present paper is an important component of the ILC damping rings, since its rise and fall time define the minimum distance between bunches and ultimately the damping rings length itself. Building on the initial results presented at EPAC '06, we report on the present status of the kicker design and define the minimum characteristics for pulsers and other subsystems. In addition to the original scheme with multiple stripline modules producing a total deflection of 5 mrad, we also investigated a scheme with a single kicker module for a reduced deflection of 1 mrad placed inside a closed orbit bump, which takes the electron closer to the extraction septum

Recent progress of fast-ion loss detector project in Asian fusion experiments

International Nuclear Information System (INIS)

Isobe, Mitsutaka; Zhang Yipo; Kim, Jun-Young

2013-01-01

The A3 foresight program is accelerating close collaboration for fast-ion diagnostics development between Asian three countries. A recent big step in our activities is that the operation of fast-ion loss detector (FILD) on HL-2A has begun lately. The localized bright spot appeared on the scintillator screen while a high-energy neutral beam was tangentially co-injected. The design of FILD system on EAST is steadily ongoing. The diagnostics port available for our purpose was decided in March, 2013. For KSTAR, the FILD is working successfully. In order to understand observed beam-ion loss signals while the RMP coils are turned on, the LORBIT code has been improved recently to treat non-axisymmetric perturbed field due to RMP coils and discreteness of TF coils. (author)

Absorption of fast waves at moderate to high ion cyclotron harmonics on DIII-D

International Nuclear Information System (INIS)

Pinsker, R.I.; Porkolab, M.; Heidbrink, W.W.; Luo, Y.; Petty, C.C.; Prater, R.; Choi, M.; Schaffner, D.A.; Baity, F.W.; Fredd, E.; Hosea, J.C.; Harvey, R.W.; Smirnov, A.P.; Murakami, M.; Zeeland, M.A. Van

2006-01-01

The absorption of fast Alfven waves (FW) by ion cyclotron harmonic damping in the range of harmonics from 4th to 8th is studied theoretically and with experiments in the DIII-D tokamak. A formula for linear ion cyclotron absorption on ions with an arbitrary distribution function which is symmetric about the magnetic field is used to estimate the single-pass damping for various cases of experimental interest. It is found that damping on fast ions from neutral beam injection can be significant even at the 8th harmonic if the fast ion beta, the beam injection energy and the background plasma density are high enough and the beam injection geometry is appropriate. The predictions are tested in several L-mode experiments in DIII-D with FW power at 60 MHz and at 116 MHz. It is found that 4th and 5th harmonic absorption of the 60 MHz power on the beam ions can be quite strong, but 8th harmonic absorption of the 116 MHz power appears to be weaker than expected. The linear modelling predicts a strong dependence of the 8th harmonic absorption on the initial pitch-angle of the injected beam, which is not observed in the experiment. Possible explanations of the discrepancy are discussed

Poisoning of liquid membrane carriers in extraction of metal ions

International Nuclear Information System (INIS)

Wang, Yuchun; Wang, Dexian

1992-01-01

As means of effective separation and preconcentration, emulsion liquid membranes (ELMs) have found application in many fields including biochemical separation, wastewater treatment, hydrometallurgy, and preconcentration in analytical chemistry. In the extraction of desired metal (scandium, mixed rare earths) ions using chelating extractants (TTA, HDEHP) as liquid membrane carriers, the carriers will become poisoned owing to the presence of even minute quantity of certain high ionic potential ions in the feed solution. The reason for the poisoning of carriers is that those ions have so much greater affinity than the desired ions for the membrane carrier that the ion-carrier coordination compound cannot be stripped at the interior interface of the membrane and gradually no more free carrier transports any metal ions across the membrane. The calculated results are in agreement with the experiments, and methods to avoid the poisoning are given in the paper

Fast-ion redistribution due to sawtooth crash in the TEXTOR tokamak measured by collective Thomson scattering

DEFF Research Database (Denmark)

Nielsen, Stefan Kragh; Bindslev, Henrik; Salewski, Mirko

2010-01-01

Here we present collective Thomson scattering measurements of 1D fast-ion velocity distribution functions in neutral beam heated TEXTOR plasmas with sawtooth oscillations. Up to 50% of the fast ions in the centre are redistributed as a consequence of a sawtooth crash. We resolve various directions...

Numerical studies of fast ion slowing down rates in cool magnetized plasma using LSP

Science.gov (United States)

Evans, Eugene S.; Kolmes, Elijah; Cohen, Samuel A.; Rognlien, Tom; Cohen, Bruce; Meier, Eric; Welch, Dale R.

2016-10-01

In MFE devices, rapid transport of fusion products from the core into the scrape-off layer (SOL) could perform the dual roles of energy and ash removal. The first-orbit trajectories of most fusion products from small field-reversed configuration (FRC) devices will traverse the SOL, allowing those particles to deposit their energy in the SOL and be exhausted along the open field lines. Thus, the fast ion slowing-down time should affect the energy balance of an FRC reactor and its neutron emissions. However, the dynamics of fast ion energy loss processes under the conditions expected in the FRC SOL (with ρe code, to examine the effects of SOL density and background B-field on the slowing-down time of fast ions in a cool plasma. As we use explicit algorithms, these simulations must spatially resolve both ρe and λDe, as well as temporally resolve both Ωe and ωpe, increasing computation time. Scaling studies of the fast ion charge (Z) and background plasma density are in good agreement with unmagnetized slowing down theory. Notably, Z-scaling represents a viable way to dramatically reduce the required CPU time for each simulation. This work was supported, in part, by DOE Contract Number DE-AC02-09CH11466.

Electron capture by fast protons from helium-like ions

International Nuclear Information System (INIS)

Samanta, R.; Purkait, M.

2011-01-01

Four-body formalism of boundary corrected continuum intermediate state (BCCIS-4B) approximation have been applied to calculate the single-electron capture cross sections by fast protons through some helium-like ions in a large energy range from 30-1000 keV. In this model, distortion has been taken into account in the entrance channel. In the final channel, the passive electron plays the role of screening of the target ion. However, continuum states of the projectile and the electron in the field of the residual target ion are included. The comparison of the results is made with those of other theoretical investigations and experimental findings. The present calculated results are found to be in good agreement with the available experimental findings. (authors)

Electroless formation of hybrid lithium anodes for fast interfacial ion transport

Energy Technology Data Exchange (ETDEWEB)

Choudhury, Snehashis; Stalin, Sanjuna; Vu, Duylinh; Fawole, Kristen; Archer, Lynden A. [School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY (United States); Tu, Zhengyuan [Department of Material Science and Engineering, Cornell University, Ithaca, NY (United States); Gunceler, Deniz [Department of Physics, Cornell University, Ithaca, NY (United States); Sundararaman, Ravishankar [Material Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY (United States)

2017-10-09

Rechargeable batteries based on metallic anodes are of interest for fundamental and application-focused studies of chemical and physical kinetics of liquids at solid interfaces. Approaches that allow facile creation of uniform coatings on these metals to prevent physical contact with liquid electrolytes, while enabling fast ion transport, are essential to address chemical instability of the anodes. Here, we report a simple electroless ion-exchange chemistry for creating coatings of indium on lithium. By means of joint density functional theory and interfacial characterization experiments, we show that In coatings stabilize Li by multiple processes, including exceptionally fast surface diffusion of lithium ions and high chemical resistance to liquid electrolytes. Indium coatings also undergo reversible alloying reactions with lithium ions, facilitating design of high-capacity hybrid In-Li anodes that use both alloying and plating approaches for charge storage. By means of direct visualization, we further show that the coatings enable remarkably compact and uniform electrodeposition. The resultant In-Li anodes are shown to exhibit minimal capacity fade in extended galvanostatic cycling when paired with commercial-grade cathodes. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

The Booster to AGS beam transfer fast kicker systems

International Nuclear Information System (INIS)

Zhang, W.; Bunicci, J.; Soukas, A.V.; Zhang, S.Y.

1992-01-01

The Brookhaven AGS Booster has a very successful commissioning period in June 1991. The third phase of that commissioning was a beam extraction test. The Booster extraction fast kicker (F3) deflected a 1.2 GeV proton beam from the Booster circulating orbit into the extraction septum aperture, partially down the extraction line to a temporary beam stop. Now, the Booster is committed to the AGS operations program for both heavy ion and proton beams. Thus, the Booster extraction and the corresponding AGS injection systems must operate routinely up to a pulse repetition frequency of 7.5 Hertz, and up to a beam energy of 1.5 Gev. The injection fast kicker is located in the A5 section of the AGS ring and is used to deflect the proton or heavy ion beam into its final AGS closed orbit. A distinctive feature of the AGS injection fast kicker modulators is the tail-bitting function required for proton beam injection. This enables the system to produce a fast current fall time to go along with the high current pulse amplitude with a fast rise time. The AGS injection fast kicker system has three pulse modulators, and each modulator consists of two thyratrons. The main PFN thyratrons switch on the current, and the tail bitting thyratrons are used to force the magnet current to decrease rapidly. Two digital pulse delay generators are used to align the main thyratrons and the tail bitting thyratrons respectively. The system has been tested and installed. The final commissioning of the Booster to AGS beam transfer line and injection is currently being undertaken. In this article, the system design, realization techniques and performance data will be presented

Fast-ion response to energetic-particle-driven MHD activity in Heliotron J

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, S.; Yamamoto, S.; Mizuuchi, T.; Nagasaki, K.; Okada, H.; Minami, T.; Hanatani, K.; Konoshima, S.; Ohshima, S.; Toushi, K.; Sano, F. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji (Japan); Nagaoka, K.; Suzuki, Y.; Takeiri, Y.; Yokoyama, M. [National Institute for Fusion Science, Toki, Gifu (Japan); Murakami, S. [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Lee, H.Y.; Nakamura, Y.; Hosaka, K. [Graduate School of Energy Science, Kyoto University, Gokasho, Uji (Japan)

2010-08-15

In Heliotron J, low magnetic shear configuration, instabilities with frequency chirping in the frequency range of Alfven eigenmodes have been observed in tangentially injected neutral beam plasmas. These modes are induced by energetic-particle driven magnetohydrodynamic (MHD) instabilities such as global Alfven eigenmode or energetic particle mode. A hybrid directional Langmuir probe system has been installed into Heliotron J to investigate the response of fast-ion fluxes to the MHD modes. A high coherent response of the ion flux to the bursting modes has been observed not only by the co-directed probe but also by the counter-directed one. A linear correlation between the response of the co-directed ion flux and the mode amplitude has been found. The radial profile of the response of the co-directed ions has decreased with the minor radius and has not been obtained significantly outside last closed flux surface. These results indicate that the fast-ion response is due to a resonant convective oscillation. The ion flux response of the counter-directed probe has appeared in the growth phase of the mode burst. Its phase relation is different from that of co-directed one and magnetic probe located at the Heliotron J vacuum vessel. Two candidates of the detected ion flux of the counter-directed probe have been discussed. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

IGUN-A program for the simulation of positive ion extraction including magnetic fields

International Nuclear Information System (INIS)

Becker, R.; Herrmannsfeldt, W.B.

1992-01-01

IGUN is a program for the simulation of positive ion extraction from plasmas. It is based on the well known program EGUN for the calculation of electron and ion trajectories in electron guns and lenses. The mathematical treatment of the plasma sheath is based on a simple analytical model, which provides a numerically stable calculation of the sheath potentials. In contrast to other ion extraction programs, IGUN is able to determine the extracted ion current in succeeding cycles of iteration by itself. However, it is also possible to set values of current, plasma density, or ion current density. Either axisymmetric or rectangular coordinates can be used, including axisymmetric or transverse magnetic fields

igun - A program for the simulation of positive ion extraction including magnetic fields

Science.gov (United States)

Becker, R.; Herrmannsfeldt, W. B.

1992-04-01

igun is a program for the simulation of positive ion extraction from plasmas. It is based on the well known program egun for the calculation of electron and ion trajectories in electron guns and lenses. The mathematical treatment of the plasma sheath is based on a simple analytical model, which provides a numerically stable calculation of the sheath potentials. In contrast to other ion extraction programs, igun is able to determine the extracted ion current in succeeding cycles of iteration by itself. However, it is also possible to set values of current, plasma density, or ion current density. Either axisymmetric or rectangular coordinates can be used, including axisymmetric or transverse magnetic fields.

Re-entering fast ion effects on NBI heating power in high-beta plasmas of the Large Helical Device

International Nuclear Information System (INIS)

Seki, Ryosuke; Watanabe, Kiyomasa; Funaba, Hisamichi; Suzuki, Yasuhiro; Sakakibara, Satoru; Ohdachi, Satoshi; Matsumoto, Yutaka; Hamamatsu, Kiyotaka

2011-10-01

We calculate the heating power of the neutral beam injection (NBI) in the = 4.8% high-beta discharge achieved in the Large Helical Device (LHD). We investigate the difference of the heating efficiency and the heating power profile between with and without the re-entering fast ion effects. When the re-entering fast ion effects are taken into account, the heating efficiency in the co injection of the NBI (co-NBI case) is improved and it is about 1.8 times larger than that without the re-entering effects. In contrast, the heating efficiency with the re-entering effects in the counter injection of the NBI (ctr-NBI case) rarely differs from that without the re-entering ones. We also study the re-entering fast ion effects on the transport properties in the LHD high beta discharges. It is found that the tendency of the thermal conductivities on the beta value is not so much sensitive with and without the re-entering effects. In addition, we investigate the difference in the re-entering fast ion effects caused by the field strength and the magnetic configuration. In the co-NBI case, the re-entering fast ion effects on the heating efficiency increases with the decrease of the field strength. In the contrast, the re-entering fast ion effects in the ctr-NBI case rarely differs by changing the field strength. (author)

High-intensity positive beams extracted from a compact double-chamber ion source

International Nuclear Information System (INIS)

Huck, H.; Somacal, H.; Di Gregorio, D.E.; Fernandez Niello, J.O.; Igarzabal, M.; Di Paolo, H.; Reinoso, M.

2005-01-01

This work presents the design and development of a simple ion source, the associated ion extraction optics, and the beam transport of a low-energy and high-current proton accelerator. In its actual version, the ion source can deliver positive proton currents up to 100 mA. This rather high beam current is achieved by adding a small ionization chamber between the discharge chamber containing the filament and the extraction electrode of the ion source. Different parameters of the ion source and the injection beam line are evaluated by means of computer simulations to optimize the beam production and transmission

A FAST AND ROBUST ALGORITHM FOR ROAD EDGES EXTRACTION FROM LIDAR DATA

Directory of Open Access Journals (Sweden)

K. Qiu

2016-06-01

Full Text Available Fast mapping of roads plays an important role in many geospatial applications, such as infrastructure planning, traffic monitoring, and driver assistance. How to extract various road edges fast and robustly is a challenging task. In this paper, we present a fast and robust algorithm for the automatic road edges extraction from terrestrial mobile LiDAR data. The algorithm is based on a key observation: most roads around edges have difference in elevation and road edges with pavement are seen in two different planes. In our algorithm, we firstly extract a rough plane based on RANSAC algorithm, and then multiple refined planes which only contains pavement are extracted from the rough plane. The road edges are extracted based on these refined planes. In practice, there is a serious problem that the rough and refined planes usually extracted badly due to rough roads and different density of point cloud. To eliminate the influence of rough roads, the technology which is similar with the difference of DSM (digital surface model and DTM (digital terrain model is used, and we also propose a method which adjust the point clouds to a similar density to eliminate the influence of different density. Experiments show the validities of the proposed method with multiple datasets (e.g. urban road, highway, and some rural road. We use the same parameters through the experiments and our algorithm can achieve real-time processing speeds.

Analytical studies of plasma extraction electrodes and ion beam formation

International Nuclear Information System (INIS)

Hassan, A.; Elsaftawy, A.; Zakhary, S. G.

2007-01-01

In this work a theoretical and computational study on the space charge dominated beams extracted from a plasma ion source through a spherical and planer electrode is simulated and optimized. The influence of some electrode parameters: axial position, electrode diameter, material and shape; on ion current extracted from a plasma source; were investigated and compared. The optimum values and conditions of the curvature of the plasma boundary, angular divergence, perveance, and the extraction gap were optimized to extract a high quality beams. It has shown that for a planar electrode system there is usually a minimum for optimum perveance versus angular divergence at about ? 0.6 for corresponding aspect ratios. This was assured by experimental data. The appropriate spherical electrode system focus the beam to a minimum value located at a distance equal to the focal length of the spherical extraction electrode.

Feasibility of ion-pair/supercritical fluid extraction of an ionic compound--pseudoephedrine hydrochloride.

Science.gov (United States)

Eckard, P R; Taylor, L T

1997-02-01

The supercritical fluid extraction (SFE) of an ionic compound, pseudoephedrine hydrochloride, from a spiked-sand surface was successfully demonstrated. The effect of carbon dioxide density (CO2), supercritical fluid composition (pure vs. methanol modified), and the addition of a commonly used reversed-phase liquid chromatographic ion-pairing reagent, 1-heptanesulfonic acid, sodium salt, on extraction efficiency was examined. The extraction recoveries of pseudoephedrine hydrochloride with the addition of the ion-pairing reagent from a spiked-sand surface were shown to be statistically greater than the extraction recoveries without the ion-pairing reagent with both pure and methanol-modified carbon dioxide.

On the meniscus formation and the negative hydrogen ion extraction from ITER neutral beam injection relevant ion source

International Nuclear Information System (INIS)

Mochalskyy, S; Wünderlich, D; Ruf, B; Fantz, U; Franzen, P; Minea, T

2014-01-01

The development of a large area (A source,ITER  = 0.9 × 2 m 2 ) hydrogen negative ion (NI) source constitutes a crucial step in construction of the neutral beam injectors of the international fusion reactor ITER. To understand the plasma behaviour in the boundary layer close to the extraction system the 3D PIC MCC code ONIX is exploited. Direct cross checked analysis of the simulation and experimental results from the ITER-relevant BATMAN source testbed with a smaller area (A source,BATMAN  ≈ 0.32 × 0.59 m 2 ) has been conducted for a low perveance beam, but for a full set of plasma parameters available. ONIX has been partially benchmarked by comparison to the results obtained using the commercial particle tracing code for positive ion extraction KOBRA3D. Very good agreement has been found in terms of meniscus position and its shape for simulations of different plasma densities. The influence of the initial plasma composition on the final meniscus structure was then investigated for NIs. As expected from the Child–Langmuir law, the results show that not only does the extraction potential play a crucial role on the meniscus formation, but also the initial plasma density and its electronegativity. For the given parameters, the calculated meniscus locates a few mm downstream of the plasma grid aperture provoking a direct NI extraction. Most of the surface produced NIs do not reach the plasma bulk, but move directly towards the extraction grid guided by the extraction field. Even for artificially increased electronegativity of the bulk plasma the extracted NI current from this region is low. This observation indicates a high relevance of the direct NI extraction. These calculations show that the extracted NI current from the bulk region is low even if a complete ion–ion plasma is assumed, meaning that direct extraction from surface produced ions should be present in order to obtain sufficiently high extracted NI current density. The calculated

Full inelastic cross section, effective stopping and ranges of fast multiply charged ions

International Nuclear Information System (INIS)

Alimov, R.A.; Arslanbekov, T.U.; Matveev, B.I.; Rakhmatov, A.S.

1994-01-01

Inelastic processes taking place in collision of fast multiply charged ions with atoms are considered on the base of mechanism of sudden momentum transfer. The simple estimations are proposed of full inelastic cross sections, effective stopping and ion ranges in gaseous medium. (author). 10 refs

Exchange of charges between fast ions and neutral atoms; Change de charges entre ions rapides et atomes neutres

Energy Technology Data Exchange (ETDEWEB)

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

1955-07-01

In this paper, we summarize the most significant theoretical and experimental results obtained so far on the exchange of charges between fast ions and neutral atoms. (author) [French] Dans l'expose qui suit, nous resumons les resultats theoriques et experimentaux interessants obtenus jusqu'a nos jours dans le domaine de l'echange de charges entre ions rapides et atomes neutres. (auteur)

Study on TAE-induced fast-ion loss process in LHD

International Nuclear Information System (INIS)

Ogawa, K.; Isobe, M.; Toi, K.; Shimizu, A.; Osakabe, M.; Spong, D.A.; Yamamoto, S.

2013-01-01

In this paper, we report experimentally observed characteristics of fast-ion loss caused by TAE in non-axisymmetric system. We also make a comparison between experiment and simulation with the aid of orbit-following particle calculation that incorporates TAE magnetic fluctuations. (J.P.N.)

Theory of kinetics and equilibrium of ion exchange-adsorption and mechanism of extracting uranium from sea-water with titanic gel

International Nuclear Information System (INIS)

Ai Hongtao

1989-01-01

An isothermal equation for ion exchange-adsorption is derived by mass action law. The equation can be used to sum up empirical and semiempirical formulas of the exchange adsorption, such as Gapon Equation, Sips Formula, Langmuir Equation and Freundlich Formula. In this paper, by adopting the ion exchange reaction to act as the determining step of the ion exchange adsorption kinetics, and exchange-adsorption kinetics equation is derived. It is verified by he results of a series of experiments in which uranium is extracted form enriched sea-water and natural sea-water with hydrous titanium oxide (titanic gel). This equation can be used to explain not only the results of test which have been applied to prove fast intraparticle diffusion of liquid film deffusion mechanism, but also test data which can be expalined by the co-controlling fast intraparticle and liquid film diffusion, and the kinetic data which can not be clarified by diffusion mechanism. It is proposed that the mechanism of the exchange adsorption of uranium from sea-water with titanic gel is a cationic exchange reaction. A method for calculating the quantity of exchange-adsorption at equilibrium is also given

Inversion methods for fast-ion velocity-space tomography in fusion plasmas

DEFF Research Database (Denmark)

Jacobsen, Asger Schou; Stagner, L.; Salewski, Mirko

2016-01-01

Velocity-space tomography has been used to infer 2D fast-ion velocity distribution functions. Here we compare the performance of five different tomographic inversion methods: truncated singular value decomposition, maximum entropy, minimum Fisher information and zeroth and first-order Tikhonov...... regularization. The inversion methods are applied to fast-ion Dα measurements taken just before and just after a sawtooth crash in the ASDEX Upgrade tokamak as well as to synthetic measurements from different test distributions. We find that the methods regularizing by penalizing steep gradients or maximizing...... entropy perform best. We assess the uncertainty of the calculated inversions taking into account photon noise, uncertainties in the forward model as well as uncertainties introduced by the regularization which allows us to distinguish regions of high and low confidence in the tomographies. In high...

Considerations on a new fast extraction kicker concept for SPS

CERN Document Server

Barnes, M

2010-01-01

An alternative extraction kicker concept is investigated for the SPS, based on open C-type kickers and a fast-bumper system. The beam is moved into the kicker gap some tens of ms before extraction. The concept is illustrated in detail with the LSS4 extraction from the SPS – very similar parameters and considerations apply to LSS6. A similar concept could also be conceived for injection but is more difficult due to the larger beam size. The technical issues are presented and the potential impact on the machine impedance outlined.

Solvent effect on the extraction and transport of lithium ions by polyethylene glycols

International Nuclear Information System (INIS)

Mishra, D; Sharma, U

1999-01-01

Extraction of lithium picrate, 2,4-dinitrophenolate and 2-nitrophenolate and their transport through membranes by di-, tri- and tetraethylene glycols as carriers are studied. Organic solvents considered as extractants and liquid membranes in terms of lithium ions extraction and transfer are arranged in the following series: methylene chloride ≥ dichloroethane ≥ chloroform ≥ carbon tetrachloride. Diethylene glycol proved the most effective solvent for lithium ions extraction and transport [ru

Effects of minority ions on the propagation of the Fast Alfven wave

International Nuclear Information System (INIS)

Wong, K.L.; Kristiansen, M.; Hagler, M.

1985-01-01

Minority ions play an important role in ICRF wave heating and fast wave current drive. The former provides supplemental heating to the plasma ions, and the latter enables a Tokamak reactor to operate in steady state. The injection of minority ions greatly perturbs the propagation and absorption properties of the fast waves provided that the excitation frequency and confining magnetic field strength make the hybrid layers exist inside the plasma. A cold-plasma slab model with gradient confining magnetic field, parabolic plasma density, vacuum layer, launching antenna and conducting walls was used in studying wave propagation with and without minority ions. The wave propagation was studied individually for each discrete toroidal eigenmode (N=Rk/sub z/). There exists an asymmetric density cutoff region which is mainly due to the density variation in a single-ion plasma. The larger the torodial mode number, the larger the density cutoff region. Therefore, there exists a maximum mode number N/sub m/, which can be excited for each operating frequency. With injection of minority ions, the cutoff region for each mode number is almost unchanged. But, if one carefully chooses the excitation frequency; the hybrid layers can exist inside the plamsa for all or part of the allowed eigenmodes. Those eigenmodes with hybrid layers inside the plasma will undergo drastic change in the propagation and absorption of the waves

Direct extraction of negative lithium ions from a lithium plasma

International Nuclear Information System (INIS)

Wada, M.; Tsuda, H.; Sasao, M.

1990-01-01

Negative lithium ions (Li - ) were directly extracted from a lithium plasma in a multiline cusp plasma container. A pair of permanent magnets mounted near the extractor electrode created the filter magnetic field that separated the extraction region plasma from the main discharge plasma. The plasma electrode facing the extraction region plasma was biased with respect to the other parts of the chamber wall, which acted as discharge anodes. The larger filter magnetic field resulted larger Li - current. When the bias to the plasma electrode was several volts positive against the anode potential, extracted Li - current took the maximum for a fixed strength of the filter field. These dependences of Li - upon the filter magnetic field and the plasma electrode bias are similar to the ones of negative hydrogen ions

A Novel Supercapacitor/Lithium-Ion Hybrid Energy System with a Fuzzy Logic-Controlled Fast Charging and Intelligent Energy Management System

Directory of Open Access Journals (Sweden)

Muhammad Adil Khan

2018-05-01

Full Text Available The electric powered wheelchair (EPW is an essential assistive tool for people with serious injuries or disability. This manuscript describes the validation of applied research for reducing the charging time of an electric wheelchair using a hybrid electric system (HES composed of a supercapacitor (SC bank and a lithium-ion battery with a fuzzy logic controller (FLC-based fast charging system for Li-ion batteries and a fuzzy logic-based intelligent energy management system (FLIEMS for controlling the power flow within the HES. The fast charging FLC was designed to drive the voltage difference (Vd among the different cells of a multi-cell battery and the cell voltage (Vc of an individual cell. These parameters (voltage difference and cell voltage were used as input voltages to reduce the charge time and activate a bypass equalization (BPE scheme. BPE was introduced in this paper so that the battery operates within the safe voltage range. For SC/Li-ion HES, the FLIEMS presented in this paper controls the bi-directional power flow to smooth the power extracted from Li-ion batteries. Moreover, a dual active bridge isolated bidirectional DC converter (DAB-IBDC was used for power conversion. The DAB-IBDC presented in this paper has the characteristics of galvanic isolation, and high power conversion efficiency compared to the conventional converter circuits due to the reduced reverse power flow and current stresses.

Gas pressure of extractive system from the high power ion source and effect of compound materials on the optical characteristics of ion

International Nuclear Information System (INIS)

Pan Zudong; Chen Miaosun; Wang Shouhu; Chen Xingqin; Ge Yisan; Fu Peng

1991-01-01

The mechanism of extractive beam from the ion source and the ion optical condition of a minimal divergence angle were introduced briefly. Two problems in researching 15 cm Duo Penning Ion Source (extractive voltage-25 kV, current-20 A) are expounded: (1) The pulse admission way makes the extractive system keeping optimum vacuum; (2) The insulating rings are made of a compound material, therefore, insulating characteristic is improved. Both the described points (1) and (2) will make a contribution to the ion optics

Self-consistent calculation of the effects of RF injection in the HHFW heating regimes on the evolution of fast ions in toroidal plasmas

Directory of Open Access Journals (Sweden)

Bertelli Nicola

2017-01-01

Full Text Available A critical question for the use of ion cyclotron range of frequency (ICRF heating in the ITER device and beyond is interaction of fast waves with energetic ion populations from neutral beam injection (NBI, fusion reactions, and minority ions accelerated by the RF waves themselves. Several experiments have demonstrated that the interaction between fast waves and fast ions can indeed be strong enough to significantly modify the NB ion population. To model the RF/fast ion interaction and the resulting fast ion distribution, a recent extension of the full wave solver TORIC v.5 that includes non-Maxwellian effects has been combined with the Monte Carlo NUBEAM code through an RF “kick” operator. In this work, we present an initial verification of the NUBEAM RF “kick” operator for high harmonic fast wave (HHFW heating regime in NSTX plasma.

Experimental and simulated fast ion velocity distributions on collective Thomson scattering diagnostic in the Large Helical Device

DEFF Research Database (Denmark)

Nishiura, M.; Kubo, S.; Tanaka, K.

2012-01-01

We have developed a collective Thomson scattering diagnostic system in the LHD. The CTS spectrum spread is observed in the frequency region corresponding to the bulk and fast ions during NB injection. The NB originated fast ions are evaluated by the MORH code for understanding the measured CTS sp...

High-performance rechargeable batteries with fast solid-state ion conductors

Energy Technology Data Exchange (ETDEWEB)

Farmer, Joseph C.

2017-06-27

A high-performance rechargeable battery using ultra-fast ion conductors. In one embodiment the rechargeable battery apparatus includes an enclosure, a first electrode operatively connected to the enclosure, a second electrode operatively connected to the enclosure, a nanomaterial in the enclosure, and a heat transfer unit.

Energy measurement of fast ions trapped in the toroidal field ripple of Tore Supra

International Nuclear Information System (INIS)

Basiuk, V.; Becoulet, A.; Hutter, T.; Martin, G.; Pecquet, A.L.; Saoutic, B.

1993-09-01

During additional heating in Tore Supra (ICRF or NBI) fast ion losses due to the toroidal field ripple were clearly measured by a set of graphite probes. This diagnostic collects the flow of fast ions entering a vertical port and usually shows a maximum flux for ions originating from the vicinity of surface δ * = 0. During the monster sawteeth regime, achieved with ICRF, a remarkable phenomenon was observed: the ejection of fast ions, not correlated with any measured MHD activity. The radial distribution of these ions is quite different from that usually observed exhibiting a peak located in the central section of the plasma. In order to measure the energy distribution of these ions, from 80 keV (energy of the neutral beam injected in Tore Supra) up to 1 MeV (expected during ICRF), a new diagnostic is under construction. The principle of the diagnostic is to discriminate the ions in energy using their Larmor radius (p = 1.3 cm for 100 keV → p = 3.6 cm for 700 keV, B = 4T). The detector is made of a hollow graphite cylinder with a small entrance slot, located in a vertical port on the ion drift side. An array of six metallic collectors placed inside the graphite cylinder intercepts the ions. The current on each collector was estimated at 10 → 100 nA, during ICRF heating. The energy resolution of this diagnostic is expected to be about 20 keV for the lowest energy range and 100 keV for the highest. This type of ruggedized detector might be extrapolated for the measurements of alpha particle losses in future DT experiments. It should also be suitable for the studies of stochastic ripple diffusion. (authors). 3 refs., 9 figs

Synchronous timing of multi-energy fast beam extraction during a single AGS cycle

International Nuclear Information System (INIS)

Gabusi, J.; Naase, S.

1985-01-01

Synchronous triggering of fast beams is required because the field of Kicker Magnets must rise within the open space between one beam bunch and the next. Within the Brookhaven AGS, Fast Extracted Beam (FEB) triggering combines nominal timing, based on beam energy with bunch-to-bunch synchronization, based on the accelerating rf waveform. During beam acceleration, a single bunch is extracted at 22 GeV/c and within the same AGS cycle, the remaining eleven bunches are extracted at 28.4 GeV/c. When the single bunch is extracted, a ''hole'', which is left in the remaining circulating beam, can appear in random locations within the second extraction during successive AGS cycles. To overcome this problem, a synchronous rf/12 counting scheme and logic circuitry are used to keep track of the bunch positions relative to each other, and to place the ''hole'' in any desired location within the second extraction. The rf/12 signal is used also to synchronize experimenters triggers

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

International Nuclear Information System (INIS)

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

2011-01-01

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

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

Science.gov (United States)

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

2011-01-01

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

Fast ion loss and radial electric field in high-aspect-ratio stellarator

International Nuclear Information System (INIS)

Itoh, Kimitaka; Sanuki, Heiji; Itoh, Sanae

1992-01-01

Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more close to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the selfconsistent electric field profile. The orbit loss becomes noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhance the negative radial electric field, and reduce the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

Fast ion loss and radial electric field in Wendelstein VII-Λ stellarator

International Nuclear Information System (INIS)

Itoh, K.; Sanuki, H.; Itoh, S.

1991-10-01

Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more closer to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the self consistent electric field profile. The orbit loss become noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhances the negative radial electric field, and reduces the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

Fast-ion transport in qmin>2, high-β steady-state scenarios on DIII-D

International Nuclear Information System (INIS)

Holcomb, C. T.; Heidbrink, W. W.; Collins, C.; Ferron, J. R.; Van Zeeland, M. A.; Garofalo, A. M.; Bass, E. M.; Luce, T. C.; Pace, D. C.; Solomon, W. M.; Mueller, D.; Grierson, B.; Podesta, M.; Gong, X.; Ren, Q.; Park, J. M.; Kim, K.; Turco, F.

2015-01-01

Results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-q min confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β N and the noninductive current drive. However, in scenarios with q min >2 that target the typical range of q 95 = 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. This enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable β N . In contrast, similar plasmas except with q min just above 1 have approximately classical fast-ion transport. Experiments that take q min >3 plasmas to higher β P with q 95 = 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-q min scenario, the high β P cases have shorter slowing-down time and lower ∇β fast , and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β N , and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q 95 , high-q min plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes

Fast ions and hot electrons in the laser--plasma interaction

International Nuclear Information System (INIS)

Gitomer, S.J.; Jones, R.D.; Begay, F.; Ehler, A.W.; Kephart, J.F.; Kristal, R.

1986-01-01

Data on the emission of energetic ions produced in laser--matter interactions have been analyzed for a wide variety of laser wavelengths, energies, and pulse lengths. Strong correlation has been found between the bulk energy per AMU for fast ions measured by charge cups and the x-ray-determined hot electron temperature. Five theoretical models have been used to explain this correlation. The models include (1) a steady-state spherically symmetric fluid model with classical electron heat conduction, (2) a steady-state spherically symmetric fluid model with flux limited electron heat conduction, (3) a simple analytic model of an isothermal rarefaction followed by a free expansion, (4) the lasneX hydrodynamics code [Comments Plasma Phys. Controlled Fusion 2, 85 (1975)], calculations employing a spherical expansion and simple initial conditions, and (5) the lasneX code with its full array of absorption, transport, and emission physics. The results obtained with these models are in good agreement with the experiments and indicate that the detailed shape of the correlation curve between mean fast ion energy and hot electron temperature is due to target surface impurities at the higher temperatures (higher laser intensities) and to the expansion of bulk target material at the lower temperatures (lower laser intensities)

Blind Extraction of Chaotic Signals by Using the Fast Independent Component Analysis Algorithm

International Nuclear Information System (INIS)

Hong-Bin, Chen; Jiu-Chao, Feng; Yong, Fang

2008-01-01

We report the results of using the fast independent component analysis (FastICA) algorithm to realize blind extraction of chaotic signals. Two cases are taken into consideration: namely, the mixture is noiseless or contaminated by noise. Pre-whitening is employed to reduce the effect of noise before using the FastICA algorithm. The correlation coefficient criterion is adopted to evaluate the performance, and the success rate is defined as a new criterion to indicate the performance with respect to noise or different mixing matrices. Simulation results show that the FastICA algorithm can extract the chaotic signals effectively. The impact of noise, the length of a signal frame, the number of sources and the number of observed mixtures on the performance is investigated in detail. It is also shown that regarding a noise as an independent source is not always correct

Non-local Fast Extraction from the CERN SPS at 100 and 440 GeV

CERN Document Server

Velotti, F M; Bartmann, W; Carlier, E; Cornelis, K; Efthymiopoulos, I; Goddard, B; Jensen, L K; Kain, V; Kowalska, M; Mertens, V; Steerenberg, R

2013-01-01

The Long Straight Section 2 (LSS2) of the CERN SPS is connected with the North Area (NA), to which the beam to date has always been extracted using a resonant extraction technique. For new proposed short- and long-baseline neutrino experiments, a fast single turn extraction to this experimental area is required. As there are no kickers in LSS2, and the integration of any new kickers with the existing electrostatic septum would be problematic, a solution has been developed to fast extract the beam using non-local extraction with other SPS kickers. Two different kicker systems have been used, the injection kicker in LSS1 and the stronger extraction kicker in LSS6 to extract 100 and 440 GeV beam, respectively. For both solutions a large emittance beam was extracted after 5 or 9 full betatron periods. The concept and simulation details are presented with the analysis of the aperture and beam loss considerations and experimental results collected during a series of beam tests.

Extraction of europium (3) ions with stearic acid

International Nuclear Information System (INIS)

Lobanov, F.I.; Gladyshchev, V.P.; Nurtaeva, A.K.; Andreeva, N.N.

1981-01-01

Extraction of europium (3) in nitric acid solutions with the melts of stearic acid and its mixtures with paraffin at (80+-1) deg C is studied. The constant of stearic acid dimerization in paraffin K 2 =9.6+-0.6 and the constant of stearic acid distribution in the paraffin-water system Ksub(D,HA)=(1.06+-0.07)x10sub(3) are determined. The diagram of europium ion extraction at initial concentrations of metal in the aqueous phase of 10 -4 -10 -3 mol/l is suggested. The compound extracted has the EuA 3 composition with extraction constant of lg Ksub(ex)=-7.58 [ru

Removal of Radioactive Nuclides by Multi-Functional Microcapsules Enclosing Inorganic Ion-Exchangers and Organic Extractants

Energy Technology Data Exchange (ETDEWEB)

Mimura, H.; Akiba, K.; Onodera, Y.

2002-02-26

The microcapsules enclosing two kinds of functional materials, inorganic ion-exchangers and organic extractants, were prepared by taking advantage of the high immobilization ability of alginate gel polymer. The fine powders of inorganic ion-exchanger and oil drops of extractant were kneaded with sodium alginate (NaALG) solution and the kneaded sol readily gelled in a salt solution of CaCl2, BaCl2 or HCl to form spherical gel particles. The uptake properties of various nuclides, 137Cs, 85Sr, 60Co, 88Y, 152Eu and 241Am, for thirty-four specimens of microcapsules in the presence of 10-1-10-4 M HNO3 were evaluated by the batch method. The distribution coefficient (Kd) of Cs+ above 103 cm3/g was obtained for the microcapsules enclosing CuFC or AMP. The Kd of Sr2+ around 102 cm3/g was obtained for the microcapsules containing clinoptilolite, antimonic acid, zeolite A, zeolite X or titanic acid. The microcapsules enclosing DEHPA exhibited relatively large Kd values of trivalent metal ions above 103 cm3/g; for example, the Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ for a favorable microcapsule (CuFC/clinoptilolite/DEHPA/CaALG) were 1.1x104, 7.5x10, 1.1x10, 1.0x104, 1.4x104, 3.4x103 cm3/g, respectively. The uptake rates of Cs+, Y3+, Eu3+ and Am3+ for this microcapsule were rather fast; the uptake percentage above 90% was obtained after 19 h-shaking and the uptake equilibrium was attained within 1 d. The AMP/CaALG exhibited high uptake ability for Cs+ even after irradiation of 188 kGy, and DEHPA/CaALG microcapsule had similar Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ ions before and after irradiation. The microcapsules with various shapes such as spherical, columnar, fibrous and filmy forms were easily prepared by changing the way of dipping kneaded sol into gelling salt solution. The microcapsules enclosing inorganic ion-exchangers and extractants have a potential possibility for the simultaneous removal of various radioactive nuclides from waste solutions.

Ion extraction capabilities of two-grid accelerator systems

International Nuclear Information System (INIS)

Rovang, D.C.; Wilbur, P.J.

1984-02-01

An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. This work resulted in a large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high. The apparatus developed for this study is also shown to be well suited measuring the electron backstreaming and electrical breakdown characteristics of two-grid accelerator systems

Thermo-mechanical design of the extraction grids for RF negative ion source at HUST

Energy Technology Data Exchange (ETDEWEB)

Zuo, Chen; Liu, Kaifeng, E-mail: kfliuhust@hust.edu.cn; Li, Dong; Mei, Zhiyuan; Zhang, Zhe; Chen, Dezhi

2017-01-15

Highlights: • An extraction system with cooling channels has been designed for HUST negative ion source. • Corresponding heat loads onto three grids has been used in thermo-mechanical analysis. • The analysis results could be very useful for driving the engineering design. - Abstract: Huazhong University of Science and Technology (HUST) is developing a small radio frequency negative ion source experimental setup to promote research on neutral beam injection ion sources. The extraction system for the negative ion source is the key component to obtain the negative ions. The extraction system is composed of three grids: the plasma grid, the extraction grid and the grounded grid. Each grid is impacted by different heat loads. As the grids have to fulfil specific requirements regarding ion extraction, beam optics, and thermo-mechanical issues, grid cooling systems have been included for ensuring reliable operation. This paper focuses on the thermo-hydraulic and thermo-mechanical design of the grids. Finite element calculations have been carried out to analyse the temperature and deformation of the grids under heat loads using the fluid dynamics code CFX. Based on these results, the cooling circuit design and cooling parameters are optimised to satisfy the grid requirements.

Scattering extraction of ions at CRYRING for SEU testing

CERN Document Server

Novák, D; Klamra, W; Norlin, L O; Bagge, L; Kaellberg, A; Paál, A; Rensfelt, K G; Molnár, J

1999-01-01

A measuring station has been built at the CRYRING heavy ion accelerator to test the Single Event Upset (SEU) phenomena in working Static RAM circuits. The setup extracts the beam using Rutherford scattering and the ions are monitored with a BaF sub 2 scintillator. SEU measurements have been performed for standard bulk CMOS memory circuits.

Symposium on fast atom and ion induced mass spectrometry of nonvolatile organic solids

International Nuclear Information System (INIS)

McNeal, C.J.

1982-01-01

The mechanisms of molecular and fragment ion production and the various parameters affecting ion yields were discussed by 6 invited speakers from Europe, Canada, and the US at this symposium. The work reported was almost equally divided between that using low-energy (keV) primary ion (or atom) beams, e.g. fast atom bombardment mass spectrometry (FABMS) and secondary ion mass spectrometry (SIMS) and that using high energy (MeV) particles, e.g. heavy ion induced mass spectrometry (HIIDMS) and 252 Cf-plasma desorption mass spectrometry ( 252 Cf-PDMS). Both theoretical foundations and observed experimental results for both techniques are included

ITER fast ion collective Thomson scattering, conceptual design of 60 GHz system

International Nuclear Information System (INIS)

Meo, F.; Bindslev, H.; Korsholm, S.B.

2007-08-01

The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma. The fast ion CTS diagnostic consists of two separate systems. Each system has its own RF launcher and separate set of detectors. The first system measures the perpendicular component of the fast ion velocity distribution. It consists of radially directed RF launcher and receiver, both located in the equatorial port on the low field side (LFS). This system will be referred to by the acronym LFS-BS system referring to the location of the receiver and the fact that it measures backscattered radiation. The second part of the CTS diagnostic measures the parallel component of the fast ion distribution. It consists of an RF launcher located in the mid-plane port on the LFS and a receiver mounted on the inner vacuum vessel wall that views the plasma from between two blanket modules. This system will be referred to as HFS-FS referring to the location of the receivers and that they measure forward scattered radiation. The design of both LFS-BS and HFS-FS receivers is aimed at measuring at different spatial locations simultaneously with no moveable components near the plasma. This report is a preliminary study of the hardware design and engineering constraints for this frequency range. Section 2 conceptually describes the two systems and their main components. Section 3 clarifies the impact of design parameters such as beam widths and scattering angle on the CTS measurements. With this in hand, the ITER measurement requirements are translated into constraints on the CTS system designs. An important result in this section is that systems can be designed inside these constraints. Section 4 outlines the technical feasibility and describes in more detail the design and the engineering

Electron-electron interaction and transfer ionization in fast ion-atom collisions

International Nuclear Information System (INIS)

Voitkiv, A B

2008-01-01

Recently it was pointed out that electron capture occurring in fast ion-atom collisions can proceed via a mechanism which earlier was not considered. In the present paper we study this mechanism in more detail. Similarly as in radiative capture, where the electron transfer occurs due to the interaction with the radiation field and proceeds via emission of a photon, within this mechanism the electron capture is caused by the interaction with another atomic electron leading mainly to the emission of the latter. In contrast to the electron-electron Thomas capture, this electron-electron (E-E) mechanism is basically a first-order one having similarities to the kinematic and radiative capture channels. It also possesses important differences with the latter two. Leading to transfer ionization, this first-order capture mechanism results in the electron emission mainly in the direction opposite to the motion of the projectile ion. The same, although less pronounced, feature is also characteristic for the momenta of the target recoil ions produced via this mechanism. It is also shown that the action of the E-E mechanism is clearly seen in recent experimental data on the transfer ionization in fast proton-helium collisions.

Sample and plume luminescence in fast heavy ion induced desorption

International Nuclear Information System (INIS)

Tuszynski, W.; Koch, K.; Hilf, E.R.

1996-01-01

The luminescence arising in 252 Cf-fission fragment induced desorption events has been measured using the time-correlated single photon counting technique. Photons emitted from the sample have been guided from a plasma desorption ion source to a photodetector by an optical fibre. Spectra and decay functions have been obtained using thin layers of Coronene or POPOP as samples. The results are strongly dependent on the acceleration field applied for ion extraction. Approximately 10 photons per fission fragment have been produced when applying no accelerating voltage. The results clearly show that these photons come from radiative electronic relaxations of molecules in the solid sample. Considerably more photons per fission fragment have been produced when applying a positive acceleration voltage. The intensity increases almost linearly for acceleration fields below 10 kV/cm and saturates at a nearly 10-fold higher value when compared to no acceleration. The intensity is also affected by the homogeneity of the accelerating field. These additional photons are attributed to radiative electronic relaxations of desorbed neutral molecules in the plume excited by inelastic collisions with accelerated positive ions. No additional photons have been observed when extracting negative ions. The negative ions produced do obviously not hit and/or excite desorbed neutral molecules, presumably due to their specific desorption characteristics. The experimental data have been analyzed by comparing with the cw and time-resolved sample luminescence obtained by optical excitation. The findings demonstrate that valuable information on ion-solid interactions, on specific desorption quantities and on processes in the plume can be obtained by measuring and analyzing the luminescence induced by the impact of high energy primary ions. (orig.)

Solid-phase extraction (SPE) of Iron using Lanthanum Silicate ion exchange

International Nuclear Information System (INIS)

Kiarostami, V.; Husain, W.

2002-01-01

Solid-phase extraction (SPE) is gaining wide use as an effective and speedy technique which reduces solvent usage, disposal costs and extraction time. The analyte is adsorbed from solution onto a solid adsorbent, which is followed by elution of the analyte with a solvent appropriate for instrumental analysis. However, there is an increasing need for new selective adsorbents to expand the area of this technique. Lanthanum silicate ion exchanger, which shows unusual selectivity elements and in this study, it was employed to develop a SPE method for iron ion. Special experiments such as determination of distribution coefficient for iron ion in different solvent systems have been determined

Quantification of the impact of large and small-scale instabilities on the fast-ion confinement in ASDEX Upgrade

DEFF Research Database (Denmark)

Geiger, B.; Weiland, M.; Mlynek, A.

2015-01-01

with up to 10 MW of heating power, the fast-ion measurements agree best with the theoretical predictions that assume a weak level anomalous fast-ion transport. This is also in agreement with measurements of the internal inductance, a Motional Stark Effect diagnostic and a novel polarimetry diagnostic...

The technology of uranium extraction from the brine with high chlorine-ion content

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.; Negmatov, Sh.I.; Barotov, B.B.

2010-01-01

Present article is devoted to technology of uranium extraction from the brine with high chlorine-ion content. The research results on uranium extraction from the brine of Sasik-Kul Lake by means of sorption method were considered. The chemical composition of salt was determined. The process of uranium sorption was described and analyzed. The technology of uranium extraction from the brine with high chlorine-ion content was proposed.

Feature-based plan adaptation for fast treatment planning in scanned ion beam therapy

International Nuclear Information System (INIS)

Chen Wenjing; Gemmel, Alexander; Rietzel, Eike

2013-01-01

We propose a plan adaptation method for fast treatment plan generation in scanned ion beam therapy. Analysis of optimized treatment plans with carbon ions indicates that the particle number modulation of consecutive rasterspots in depth shows little variation throughout target volumes with convex shape. Thus, we extract a depth-modulation curve (DMC) from existing reference plans and adapt it for creation of new plans in similar treatment situations. The proposed method is tested with seven CT serials of prostate patients and three digital phantom datasets generated with the MATLAB code. Plans are generated with a treatment planning software developed by GSI using single-field uniform dose optimization for all the CT datasets to serve as reference plans and ‘gold standard’. The adapted plans are generated based on the DMC derived from the reference plans of the same patient (intra-patient), different patient (inter-patient) and phantoms (phantom-patient). They are compared with the reference plans and a re-positioning strategy. Generally, in 1 min on a standard PC, either a physical plan or a biological plan can be generated with the adaptive method provided that the new target contour is available. In all the cases, the V95 values of the adapted plans can achieve 97% for either physical or biological plans. V107 is always 0 indicating no overdosage, and target dose homogeneity is above 0.98 in all cases. The dose received by the organs at risk is comparable to the optimized plans. The plan adaptation method has the potential for on-line adaptation to deal with inter-fractional motion, as well as fast off-line treatment planning, with either the prescribed physical dose or the RBE-weighted dose. (paper)

Measurements of the fast ion distribution during neutral beam injection and ion cyclotron heating in ATF [Advanced Toroidal Facility

International Nuclear Information System (INIS)

Wade, M.R.; Kwon, M.; Thomas, C.E.; Colchin, R.J.; England, A.C.; Gossett, J.M.; Horton, L.D.; Isler, R.C.; Lyon, J.F.; Rasmussen, D.A.; Rayburn, T.M.; Shepard, T.D.; Bell, G.L.; Fowler, R.H.; Morris, R.N.

1990-01-01

A neutral particle analyzer (NPA) with horizontal and vertical scanning capability has been used to make initial measurements of the fast ion distribution during neutral beam injection (NBI) and ion cyclotron heating (ICH) on the Advanced Toroidal Facility (ATF). These measurements are presented and compared with the results of modeling codes that predict the analyzer signals during these heating processes. 6 refs., 5 figs

Building 1D resonance broadened quasilinear (RBQ) code for fast ions Alfvénic relaxations

Science.gov (United States)

Gorelenkov, Nikolai; Duarte, Vinicius; Berk, Herbert

2016-10-01

The performance of the burning plasma is limited by the confinement of superalfvenic fusion products, e.g. alpha particles, which are capable of resonating with the Alfvénic eigenmodes (AEs). The effect of AEs on fast ions is evaluated using a resonance line broadened diffusion coefficient. The interaction of fast ions and AEs is captured for cases where there are either isolated or overlapping modes. A new code RBQ1D is being built which constructs diffusion coefficients based on realistic eigenfunctions that are determined by the ideal MHD code NOVA. The wave particle interaction can be reduced to one-dimensional dynamics where for the Alfvénic modes typically the particle kinetic energy is nearly constant. Hence to a good approximation the Quasi-Linear (QL) diffusion equation only contains derivatives in the angular momentum. The diffusion equation is then one dimensional that is efficiently solved simultaneously for all particles with the equation for the evolution of the wave angular momentum. The evolution of fast ion constants of motion is governed by the QL diffusion equations which are adapted to find the ion distribution function.

Complexation-induced supramolecular assembly drives metal-ion extraction.

Science.gov (United States)

Ellis, Ross J; Meridiano, Yannick; Muller, Julie; Berthon, Laurence; Guilbaud, Philippe; Zorz, Nicole; Antonio, Mark R; Demars, Thomas; Zemb, Thomas

2014-09-26

Combining experiment with theory reveals the role of self-assembly and complexation in metal-ion transfer through the water-oil interface. The coordinating metal salt Eu(NO3)3 was extracted from water into oil by a lipophilic neutral amphiphile. Molecular dynamics simulations were coupled to experimental spectroscopic and X-ray scattering techniques to investigate how local coordination interactions between the metal ion and ligands in the organic phase combine with long-range interactions to produce spontaneous changes in the solvent microstructure. Extraction of the Eu(3+)-3(NO3(-)) ion pairs involves incorporation of the "hard" metal complex into the core of "soft" aggregates. This seeds the formation of reverse micelles that draw the water and "free" amphiphile into nanoscale hydrophilic domains. The reverse micelles interact through attractive van der Waals interactions and coalesce into rod-shaped polynuclear Eu(III) -containing aggregates with metal centers bridged by nitrate. These preorganized hydrophilic domains, containing high densities of O-donor ligands and anions, provide improved Eu(III) solvation environments that help drive interfacial transfer, as is reflected by the increasing Eu(III) partitioning ratios (oil/aqueous) despite the organic phase approaching saturation. For the first time, this multiscale approach links metal-ion coordination with nanoscale structure to reveal the free-energy balance that drives the phase transfer of neutral metal salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Operator care and eco-concerned development of a fast, facile and economical assay for basic nitrogenous drugs based on simplified ion-pair mini-scale extraction using safer solvent combined with drop-based spectrophotometry.

Science.gov (United States)

Plianwong, Samarwadee; Sripattanaporn, Areerut; Waewsa-nga, Kwanrutai; Buacheen, Parin; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak

2012-08-30

A fast, facile, and economical assay for basic nitrogenous drugs has been developed based on the mini-scale extraction of the drug-dye ion pair complex combined with the use of safe-for-analyst and eco-friendlier organic extractant and drop-based micro-spectrophotometry. Instead of using large volume devices, the extraction was simply carried out in typical 1.5 mL microcentrifuge tubes along with the use of micropipettes for accurate transfer of liquids, vortex mixer for efficient partitioning of solutes and benchtop centrifuge for rapid phase separation. In the last step, back-extraction was performed by using the microvolume of acidic solution in order to concentrate the colored species into a confined aqueous microdrop and to keep the analyst away from unwanted contact and inhalation of organic solvents during the quantitation step which was achieved by using cuvetteless UV-vis micro-spectrophotometry without any prior dilutions. Using chlorpheniramine maleate as a representative analyte and n-butyl acetate as a less toxic and non-ozone depleting extractant, the miniaturized method was less laborious and much faster. It was accurate, precise and insensitive to the interferences from common excipients. Notably, it gave the assay results of drug in tablets and oral solution comparable to the large-scale pharmacopeial method while the consumption of organic solvents and the release of wastes were lowered by 200-400 folds. Copyright © 2012 Elsevier B.V. All rights reserved.

Fast heavy-ion radiation damage of glycine in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Nomura, Shinji [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Tsuchida, Hidetsugu, E-mail: tsuchida@nucleng.kyoto-u.ac.jp [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan); Furuya, Ryosuke [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Majima, Takuya; Itoh, Akio [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan)

2016-12-15

Fast heavy-ion radiolysis of biomolecules in aqueous solution is investigated for an atomistic understanding of radiation damage to normal cells during heavy-particle beam therapy. The smallest amino acid glycine was used as a model biomaterial. Microjets of aqueous glycine solutions under vacuum were irradiated with 4.0-MeV carbon ions corresponding to energies in the Bragg peak region. To understand the effects of the water environment on molecular damage, the yield of glycine dissociation was measured by secondary ion mass spectroscopy. The yield was significantly reduced relative to gas-phase glycine targets. This implies that the numerous water molecules surrounding a single glycine molecule act as a buffer that suppresses dissociation. This is an environmental effect similar to that observed for other biomolecular cluster targets.

Fast Ion Effects During Test Blanket Module Simulation Experiments in DIII-D

International Nuclear Information System (INIS)

Kramer, G.J.; Budny, R.V.; Ellis, R.; Gorelenkova, M.; Heidbrink, W.W.; Kurki-Suonio, T.; Nazikian, R.; Salmi, A.; Schaffer, M.J.; Shinohara, K.; Snipes, J.A.; Spong, D.A.; Koskela, T.; Van Zeeland, M.A.

2011-01-01

Fast beam-ion losses were studied in DIII-D in the presence of a scaled mockup of two Test Blanket Modules (TBM) for ITER. Heating of the protective tiles on the front of the TBM surface was found when neutral beams were injected and the TBM fields were engaged. The fast-ion core confinement was not significantly affected. Different orbit-following codes predict the formation of a hot spot on the TBM surface arising from beam-ions deposited near the edge of the plasma. The codes are in good agreement with each other on the total power deposited at the hot spot predicting an increase in power with decreasing separation between the plasma edge and the TBM surface. A thermal analysis of the heat flow through the tiles shows that the simulated power can account for the measured tile temperature rise. The thermal analysis, however, is very sensitive to the details of the localization of the hot spot which is predicted to be different among the various codes.

Ion desorption from solid surfaces under slow (KeV) and fast (MeV) ion sputtering. Influence of the charge state and of the incidence angle on the input channel

International Nuclear Information System (INIS)

Joret, H.

1990-06-01

Solid surfaces of organic and inorganic materials have been bombarded by fast heavy ions (several MeV). It is shown that the charge state of the projectile has a strong influence on the atomic and molecular ion desorption yield. Experimental studies proved that molecular ions can be emitted intact from deep layers underneath the surface (volume emission) with the existence of a crater emission. On the other hand light ions like H(+), H(+)-2, H(+)-3 are emitted from the surface of the solid in a time around 10 -16 second. The H(+) depends on the incident charge state g-i. When using slow ions (keV) the same dependence was observed for the first time and compared to the fast ion results. The equilibrum charge state of fast ions passing through solids was measured. The influence of the angle of incidence was investigated. Langmuir-Blodgett films of fatty acid were used. A geometrical model is developed for the 50 angstroms layer [fr

The role of proteins and metal ions in the protection of chromatin DNA at fast neutrons action

International Nuclear Information System (INIS)

Radu, L.; Preoteasa, V.; Radulescu, I.; Constantinescu, B.

1997-01-01

The role of chromatin proteins and of some ions on the fast neutrons actions on chromatin DNA from rat Walker tumors was analysed. The DNA in chromatin is effectively protected against fast neutrons actions by DNA bound proteins and specially by histones, because of the limited accessibility of the condensed chromatin DNA to hydroxyl radicals and of the scavenging of radicals by the chromatin proteins. The ions utilised protect chromatin DNA against the damage produced ed by fast neutrons, through the induction of structural DNA changes with a less accessibility to OH radicals. (authors)

Studies on the Extraction Region of the Type VI RF Driven H- Ion Source

Science.gov (United States)

McNeely, P.; Bandyopadhyay, M.; Franzen, P.; Heinemann, B.; Hu, C.; Kraus, W.; Riedl, R.; Speth, E.; Wilhelm, R.

2002-11-01

IPP Garching has spent several years developing a RF driven H- ion source intended to be an alternative to the current ITER (International Thermonuclear Experimental Reactor) reference design ion source. A RF driven source offers a number of advantages to ITER in terms of reduced costs and maintenance requirements. Although the RF driven ion source has shown itself to be competitive with a standard arc filament ion source for positive ions many questions still remain on the physics behind the production of the H- ion beam extracted from the source. With the improvements that have been implemented to the BATMAN (Bavarian Test Machine for Negative Ions) facility over the last two years it is now possible to study both the extracted ion beam and the plasma in the vicinity of the extraction grid in greater detail. This paper will show the effect of changing the extraction and acceleration voltage on both the current and shape of the beam as measured on the calorimeter some 1.5 m downstream from the source. The extraction voltage required to operate in the plasma limit is 3 kV. The perveance optimum for the extraction system was determined to be 2.2 x 10-6 A/V3/2 and occurs at 2.7 kV extraction voltage. The horizontal and vertical beam half widths vary as a function of the extracted ion current and the horizontal half width is generally smaller than the vertical. The effect of reducing the co-extracted electron current via plasma grid biasing on the H- current extractable and the beam profile from the source is shown. It is possible in the case of a silver contaminated plasma to reduce the co-extracted electron current to 20% of the initial value by applying a bias of 12 V. In the case where argon is present in the plasma, biasing is observed to have minimal effect on the beam half width but in a pure hydrogen plasma the beam half width increases as the bias voltage increases. New Langmuir probe studies that have been carried out parallel to the plasma grid (in the

The Impact of Beam Deposition on Bootstrap Current of Fast Ion Produced by Neutral Beam Tangential Injection

International Nuclear Information System (INIS)

Huang Qian-Hong; Gong Xue-Yu; Lu Xing-Qiang; Yu Jun; Cao Jin-Jia

2015-01-01

The density profile of fast ions arising from a tangentially injected diffuse neutral beam in tokamak plasma is calculated. The effects of mean free paths and beam tangency radius on the density profile are discussed under typical HL-2A plasmas parameters. The results show that the profile of fast ions is strongly peaked at the center of the plasma when the mean free path at the maximum deuteron density is larger than the minor radius, while the peak value decreases when the mean free path at the maximum deuteron density is larger than twice that of the minor radius due to the beam transmission loss. Moreover, the bootstrap current of fast ions for various mean free paths at the maximum deuteron density is calculated and its density is proved to be closely related to the deposition of the neutral beam. With the electron return current considered, the net current density obviously decreases. Meanwhile, the peak central fast ion density increases when the beam tangency radius approaches the major radius, and the net bootstrap current increases rapidly with the increasing beam tangency radius. (paper)

Transmission of fast molecular ions through thin foils

International Nuclear Information System (INIS)

Pietsch, W.J.; Gemmell, D.S.; Cooney, P.J.; Kanter, E.P.; Kurath, D.; Ratkowski, A.J.; Vager, Z.; Zabransky, B.J.

1979-01-01

New results on the transmission of fast molecular ions through thin foils are presented and a mechanism for the transmission process is proposed. The main feature of the postulated mechanism is that a finite fraction of the incident molecular beam does not undergo a strong Coulomb explosion while traversing the foil. Because the emerging fragments are at large internuclear separations, there is an enhanced probability for the formation of bound, long-range, excited electronic states following electron capture at the rear surface of the target

Turbulent transport stabilization by ICRH minority fast ions in low rotating JET ILW L-mode plasmas

Science.gov (United States)

Bonanomi, N.; Mantica, P.; Di Siena, A.; Delabie, E.; Giroud, C.; Johnson, T.; Lerche, E.; Menmuir, S.; Tsalas, M.; Van Eester, D.; Contributors, JET

2018-05-01

The first experimental demonstration that fast ion induced stabilization of thermal turbulent transport takes place also at low values of plasma toroidal rotation has been obtained in JET ILW (ITER-like wall) L-mode plasmas with high (3He)-D ICRH (ion cyclotron resonance heating) power. A reduction of the gyro-Bohm normalized ion heat flux and higher values of the normalized ion temperature gradient have been observed at high ICRH power and low NBI (neutral beam injection) power and plasma rotation. Gyrokinetic simulations indicate that ITG (ion temperature gradient) turbulence stabilization induced by the presence of high-energetic 3He ions is the key mechanism in order to explain the experimental observations. Two main mechanisms have been identified to be responsible for the turbulence stabilization: a linear electrostatic wave-fast particle resonance mechanism and a nonlinear electromagnetic mechanism. The dependence of the stabilization on the 3He distribution function has also been studied.

Consistency between real and synthetic fast-ion measurements at ASDEX Upgrade

DEFF Research Database (Denmark)

Rasmussen, Jesper; Nielsen, Stefan Kragh; Pedersen, Morten Stejner

2015-01-01

that theory and measurements generally agree within these uncertainties for all three diagnostics during heating phases with either one or two neutral beam injection sources. This suggests that the measurements can be described by the same model assuming classical slowing down of fast ions. Since the three...

Complexation and extraction of series 4f, 5f and 4d ions by dialkyldithiophosphoric acids

International Nuclear Information System (INIS)

Fitoussi, Richard.

1982-04-01

A study was carried out on the complexing and extracting properties of various dialkyldithiophosphoric acids towards ions of the 4f, 5f and 4d series. Sulphurated donors complex and extract ions of the 4f and 5f series less strongly than their oxygenated homologues. However the affinity of trivalent actinide ions for dialkythiophosphate ions is shown to be greater than that of lanthanides. The conditions of ruthenium extraction from nitric acid are defined [fr

Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

International Nuclear Information System (INIS)

Bindslev, H; Nielsen, S K; Porte, L; Hoekzema, J A; Korsholm, S B; Meo, F; Michelsen, P K; Michelsen, S; Oosterbeek, J W; Tsakadze, E L; Westerhof, E; Woskov, P

2007-01-01

The dynamics of fast ion populations in the TEXTOR tokamak are measured by collective Thomson scattering of millimetre wave radiation generated by a gyrotron operated at 110 GHz and 100-150 kW. Temporal evolution of the energetic ion velocity distribution at switch on of neutral beam injection (NBI) and the slowdown after switch off of NBI are measured. The turn on phase of the NBI has, furthermore, been measured in plasmas with a range of electron densities and temperatures. All of these measurements are shown to be in good agreement with simple Fokker-Planck modelling. Bulk ion rotation velocity is also measured

Fast Thermal Runaway Detection for Lithium-Ion Cells in Large Scale Traction Batteries

Directory of Open Access Journals (Sweden)

Sascha Koch

2018-03-01

Full Text Available Thermal runaway of single cells within a large scale lithium-ion battery is a well-known risk that can lead to critical situations if no counter measures are taken in today’s lithium-ion traction batteries for battery electric vehicles (BEVs, plug-in hybrid electric vehicles (PHEV and hybrid electric vehicles (HEVs. The United Nations have published a draft global technical regulation on electric vehicle safety (GTR EVS describing a safety feature to warn passengers in case of a thermal runaway. Fast and reliable detection of faulty cells undergoing thermal runaway within the lithium-ion battery is therefore a key factor in battery designs for comprehensive passenger safety. A set of various possible sensors has been chosen based on the determined cell thermal runaway impact. These sensors have been tested in different sized battery setups and compared with respect to their ability of fast and reliable thermal runaway detection and their feasibility for traction batteries.

Selective chelation-supercritical fluid extraction of metal ions from waste materials

International Nuclear Information System (INIS)

Wai, C.N.; Laintz, K.E.; Yonker, C.R.

1993-01-01

The removal of toxic organics, metals, and radioisotopes from solids or liquids is a major concern in the treatment of industrial and nuclear wastes. For this reason, developing methods for selective separation of toxic metals and radioactive materials from solutions of complex matrix is an important problem in environmental research. Recent developments indicate supercritical fluids are good solvents for organic compounds. Many gases become supercritical fluids under moderate temperatures and pressures. For example, the critical temperature and pressure of carbon dioxide are 31 degrees C and 73 atm, respectively. The high diffusivity, low viscosity, and T-P dependence of solvent strength are some attractive properties of supercritical fluid extraction (SFE). Since CO 2 offers the additional benefits of stability and non-toxicity, the SFE technique avoids generation of organic liquid waste and exposure of personnel to toxic solvents. While direct extraction of metal ions by supercritical fluids is highly inefficient, these ions when complexed with organic ligands become quite soluble in supercritical fluids. Specific ligands can be used to achieve selective extraction of metal ions in this process. After SFE, the fluid phase can be depressurized for precipitation of the metal chelates and recycled. The ligand can also be regenerated for repeated use. The success of this selective chelation-supercritical fluid extraction (SC-SFE) process depends on a number of factors including the efficiencies of the selective chelating agents, solubilities of metal chelates in supercritical fluids, rate of extraction, ease of regeneration of the ligands, etc. In this report, the authors present recent results on the studies of the solubilities of metal chelates in supercritical CO 2 , experimental ions from aqueous solution, and the development of selective chelating agents (ionizable crown ethers) for the extraction of lanthanides and actinides

Losses of neutral injected fast ions due to adiabaticity breaking processes in a field-reversed configuration

International Nuclear Information System (INIS)

Takahashi, Toshiki; Inoue, Koji; Ishizuka, Takashi; Kondoh, Yoshiomi; Iwasawa, Naotaka

2004-02-01

Losses of neutral beam (NB) injected fast ions from the confinement region of a Field-Reversed Configuration (FRC) with a strong magnetic mirror are numerically analyzed for parameters relevant to NB injection experiments on the FIX (FRC injection experiment) device [T. Asai et al., Phys. Plasmas 7, 2294 (2000)]. Ionization processes of beam particles are calculated by the Monte Carlo method. The confinement of beam ions is discussed with the concept of accessible regions that restrict the ion excursion and are determined from two constants of motion, the kinetic energy and canonical angular momentum, in the case of an axisymmetric and a steady state FRC without an electrostatic field. From the calculation of the accessible regions, it is found that all the fast ions suffer from the orbit loss on the wall surface and/or the end loss. Single particle orbits are also calculated to find a difference of confinement properties from the results by employing the accessible regions. The magnetic moment is observed to show non-adiabatic motions of the beam ions, which cause a gradual orbit loss on the wall even in a case that a strong magnetic mirror is applied. The results show that the correlation of the magnetic moment disappears as the fast ions experience the density gradient around the separatrix surface and the field-null points. (author)

A gyrokinetic calculation of transmission and reflection of the fast wave in the ion cyclotron range of frequencies

International Nuclear Information System (INIS)

Lashmore-Davies, C.N.; Fuchs, V.; Dendy, R.O.

1993-01-01

A full-wave equation has been obtained from the gyrokinetic theory for the fast wave traversing a minority cyclotron resonance [Phys. Fluids B 4, 493 (1992)] with the aid of the fast wave approximation [Phys. Fluids 31, 1614 (1988)]. This theory describes the transmission, reflection, and absorption of the fast wave for arbitrary values of the parallel wave number. For oblique propagation the absorption is due to both ion cyclotron damping by minority ions and mode conversion to the ion Bernstein wave. The results for a 3 He minority in a D plasma indicate that for perpendicular propagation and minority temperatures of a few keV the power lost by the fast wave is all mode converted whereas for minority temperatures ∼100 keV∼30% of the incident power is dissipated by the minority ions due to the gyrokinetic correction. The gyrokinetic correction also results in a significant reduction in the reflection coefficient for low field side incidence when k zLB approx-lt 1 and the minority and hybrid resonances overlap

Extraction of metal ions by neutral β-diphosphoramides

International Nuclear Information System (INIS)

Madic, C.

1990-01-01

The extracting ability of β-diphosphoramides of the type R-N[P(O)(NMe 2 ) 2 ] 2 with R=-CH 3 (NIPA), -C 12 H 25 (ODIPA), or -C 16 H 33 (OHDIPA) for metal ions such as lanthanides, uranyl, and the transuranium elements Am(III) and Pu(IV) has been studied. Extraction yields depend on the nature of the ligand, the organic diluent (nitromethane, kerosene, tert-butylbenzene), the concentration of nitric acid in the aqueous phase, and the ligand-to-metal ratio, Q. The results show that the bidentate phosphoramides are very efficient extractants for all of the metals studied, even at low ratios Q. The presence of nitric acid generally enhances the extraction yields. On the other hand, selectivity is rather poor with these ligands. A particular effort has been made to determine the nature of extracted species by NMR spectroscopy

Extraction mechanism of U(VI) ions by N,N-dialkylamides

International Nuclear Information System (INIS)

Descouls, N.; Musikas, C.

1985-09-01

N,N dialkylamides are good extractants of UO 2 2+ ions from the nitric solutions obtained on dissolution of nuclear irradiated fuels. The extraction mechanism of U(VI) ions proved to be rather complex. Two species were identified by spectrophotometry in the organic phase: UO 2 (NO 3 ) 2 L 2 (1) and UO 2 (NO 3 ) 3 HL (2), L standing for the amide molecule. The complex (1) is typical for neutral molecules extractants. However, when log D(U(VI)) is plotted against log C (amide), the slope of the straight line obtained is greater than 2, which suggests that amide (1) interactions take place in the 2sup(nd) coordination sphere of U(VI) ions. The crystal structure of (1) where L is the N,N-di-n-butyldodecanamide show that Van der Waals interactions occur between the dodecyl chains of two (1) molecules. The complex (2) is characteristic for anionic extractants. For the amide molecules studied, it takes place in very acidic media. In order to investigate the nature of the UO 2 (NO 3 ) 3 HL complex, the infra-red shift of νc=0 vibration were compared in the following compounds: free amide, HNO 3 - L, phenol L, UO 2 (NO 3 ) 3 HL. The results are discussed. 14 refs [fr

Ion-driver fast ignition: Reducing heavy-ion fusion driver energy and cost, simplifying chamber design, target fab, tritium fueling and power conversion

International Nuclear Information System (INIS)

Logan, G.; Callahan-Miller, D.; Perkins, J.; Caporaso, G.; Tabak, M.; Moir, R.; Meier, W.; Bangerter, Roger; Lee, Ed

1998-01-01

Ion fast ignition, like laser fast ignition, can potentially reduce driver energy for high target gain by an order of magnitude, while reducing fuel capsule implosion velocity, convergence ratio, and required precisions in target fabrication and illumination symmetry, all of which should further improve and simplify IFE power plants. From fast-ignition target requirements, we determine requirements for ion beam acceleration, pulse-compression, and final focus for advanced accelerators that must be developed for much shorter pulses and higher voltage gradients than today's accelerators, to deliver the petawatt peak powers and small focal spots (∼100 (micro)m) required. Although such peak powers and small focal spots are available today with lasers, development of such advanced accelerators is motivated by the greater likely efficiency of deep ion penetration and deposition into pre-compressed 1000x liquid density DT cores. Ion ignitor beam parameters for acceleration, pulse compression, and final focus are estimated for two examples based on a Dielectric Wall Accelerator; (1) a small target with ρr ∼ 2 g/cm 2 for a small demo/pilot plant producing ∼40 MJ of fusion yield per target, and (2) a large target with ρr ∼ 10 g/cm 2 producing ∼1 GJ yield for multi-unit electricity/hydrogen plants, allowing internal T-breeding with low T/D ratios, >75 % of the total fusion yield captured for plasma direct conversion, and simple liquid-protected chambers with gravity clearing. Key enabling development needs for ion fast ignition are found to be (1) ''Close-coupled'' target designs for single-ended illumination of both compressor and ignitor beams; (2) Development of high gradient (>25 MV/m) linacs with high charge-state (q ∼ 26) ion sources for short (∼5 ns) accelerator output pulses; (3) Small mm-scale laser-driven plasma lens of ∼10 MG fields to provide steep focusing angles close-in to the target (built-in as part of each target); (4) beam space charge

Ion-driver fast ignition: Reducing heavy-ion fusion driver energy and cost, simplifying chamber design, target fab, tritium fueling and power conversion

Energy Technology Data Exchange (ETDEWEB)

Logan, G.; Callahan-Miller, D.; Perkins, J.; Caporaso, G.; Tabak, M.; Moir, R.; Meier, W.; Bangerter, Roger; Lee, Ed

1998-04-01

Ion fast ignition, like laser fast ignition, can potentially reduce driver energy for high target gain by an order of magnitude, while reducing fuel capsule implosion velocity, convergence ratio, and required precisions in target fabrication and illumination symmetry, all of which should further improve and simplify IFE power plants. From fast-ignition target requirements, we determine requirements for ion beam acceleration, pulse-compression, and final focus for advanced accelerators that must be developed for much shorter pulses and higher voltage gradients than today's accelerators, to deliver the petawatt peak powers and small focal spots ({approx}100 {micro}m) required. Although such peak powers and small focal spots are available today with lasers, development of such advanced accelerators is motivated by the greater likely efficiency of deep ion penetration and deposition into pre-compressed 1000x liquid density DT cores. Ion ignitor beam parameters for acceleration, pulse compression, and final focus are estimated for two examples based on a Dielectric Wall Accelerator; (1) a small target with {rho}r {approx} 2 g/cm{sup 2} for a small demo/pilot plant producing {approx}40 MJ of fusion yield per target, and (2) a large target with {rho}r {approx} 10 g/cm{sup 2} producing {approx}1 GJ yield for multi-unit electricity/hydrogen plants, allowing internal T-breeding with low T/D ratios, >75 % of the total fusion yield captured for plasma direct conversion, and simple liquid-protected chambers with gravity clearing. Key enabling development needs for ion fast ignition are found to be (1) ''Close-coupled'' target designs for single-ended illumination of both compressor and ignitor beams; (2) Development of high gradient (>25 MV/m) linacs with high charge-state (q {approx} 26) ion sources for short ({approx}5 ns) accelerator output pulses; (3) Small mm-scale laser-driven plasma lens of {approx}10 MG fields to provide steep focusing angles

A model for negative ion extraction and comparison of negative ion optics calculations to experimental results

International Nuclear Information System (INIS)

Pamela, J.

1990-10-01

Negative ion extraction is described by a model which includes electron diffusion across transverse magnetic fields in the sheath. This model allows a 2-Dimensional approximation of the problem. It is used to introduce electron space charge effects in a 2-D particle trajectory code, designed for negative ion optics calculations. Another physical effect, the stripping of negative ions on neutral gas atoms, has also been included in our model; it is found to play an important role in negative ion optics. The comparison with three sets of experimental data from very different negative ion accelerators, show that our model is able of accurate predictions

Analysis for extraction and bunching of ion beam from spherical reflex triode

International Nuclear Information System (INIS)

Kawata, Shigeo; Abe, Takashi; Kasuya, Koichi; Niu, Keishiro.

1978-11-01

Since an ion beam is hoped to impinge on a target in a spherically symmetric way for inertial confinement fusion, an analysis is developed here for the intense ion beam which is extracted from a spherical reflex triode. The basic equations are the Poisson equation for the electric potential and the conservation equations of energies for the ion and electron velocities. According to the asymptotic solution, the extracted ion-beam-current density is proportional to the power of 3/2 of the voltage imposed on the triode. This dependence of the current density on the voltage is improved to be the power of 1.6 by the numerical analysis. A special time-dependence of the ion-beam power at the target surface is required for an optimal implosion of the target. Using the bunching theory for the ion beam, we derive numerically an optimal time-dependence of the voltage imposed on the triode. Asymptotic forms are also obtained analytically for the voltage. (author)

Spectroscopic Measurements of the Ion Velocity Distribution at the Base of the Fast Solar Wind

Science.gov (United States)

Jeffrey, Natasha L. S.; Hahn, Michael; Savin, Daniel W.; Fletcher, Lyndsay

2018-03-01

In situ measurements of the fast solar wind reveal non-thermal distributions of electrons, protons, and minor ions extending from 0.3 au to the heliopause. The physical mechanisms responsible for these non-thermal properties and the location where these properties originate remain open questions. Here, we present spectroscopic evidence, from extreme ultraviolet spectroscopy, that the velocity distribution functions (VDFs) of minor ions are already non-Gaussian at the base of the fast solar wind in a coronal hole, at altitudes of thermal equilibrium, (b) fluid motions such as non-Gaussian turbulent fluctuations or non-uniform wave motions, or (c) some combination of both. These observations provide important empirical constraints for the source region of the fast solar wind and for the theoretical models of the different acceleration, heating, and energy deposition processes therein. To the best of our knowledge, this is the first time that the ion VDF in the fast solar wind has been probed so close to its source region. The findings are also a timely precursor to the upcoming 2018 launch of the Parker Solar Probe, which will provide the closest in situ measurements of the solar wind at approximately 0.04 au (8.5 solar radii).

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

International Nuclear Information System (INIS)

Kapetanakos, C.A.

1981-01-01

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

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

Science.gov (United States)

Garcia, J.; Görler, T.; Jenko, F.

2018-05-01

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

Interaction of Fast Ions with Global Plasma Modes in the C-2 Field Reversed Configuration Experiment

Science.gov (United States)

Smirnov, Artem; Dettrick, Sean; Clary, Ryan; Korepanov, Sergey; Thompson, Matthew; Trask, Erik; Tuszewski, Michel

2012-10-01

A high-confinement operating regime [1] with plasma lifetimes significantly exceeding past empirical scaling laws was recently obtained by combining plasma gun edge biasing and tangential Neutral Beam Injection (NBI) in the C-2 field-reversed configuration (FRC) experiment [2, 3]. We present experimental and computational results on the interaction of fast ions with the n=2 rotational and n=1 wobble modes in the C-2 FRC. It is found that the n=2 mode is similar to quadrupole magnetic fields in its detrimental effect on the fast ion transport due to symmetry breaking. The plasma gun generates an inward radial electric field, thus stabilizing the n=2 rotational instability without applying the quadrupole magnetic fields. The resultant FRCs are nearly axisymmetric, which enables fast ion confinement. The NBI further suppresses the n=2 mode, improves the plasma confinement characteristics, and increases the plasma configuration lifetime [4]. The n=1 wobble mode has relatively little effect on the fast ion transport, likely due to the approximate axisymmetry about the displaced plasma column. [4pt] [1] M. Tuszewski et al., Phys. Rev. Lett. 108, 255008 (2012).[0pt] [2] M. Binderbauer et al., Phys. Rev. Lett. 105, 045003 (2010).[0pt] [3] H.Y. Guo et al., Phys. Plasmas 18, 056110 (2011).[0pt] [4] M. Tuszewski et al., Phys. Plasmas 19, 056108 (2012)

Massive parallel 3D PIC simulation of negative ion extraction

Science.gov (United States)

Revel, Adrien; Mochalskyy, Serhiy; Montellano, Ivar Mauricio; Wünderlich, Dirk; Fantz, Ursel; Minea, Tiberiu

2017-09-01

The 3D PIC-MCC code ONIX is dedicated to modeling Negative hydrogen/deuterium Ion (NI) extraction and co-extraction of electrons from radio-frequency driven, low pressure plasma sources. It provides valuable insight on the complex phenomena involved in the extraction process. In previous calculations, a mesh size larger than the Debye length was used, implying numerical electron heating. Important steps have been achieved in terms of computation performance and parallelization efficiency allowing successful massive parallel calculations (4096 cores), imperative to resolve the Debye length. In addition, the numerical algorithms have been improved in terms of grid treatment, i.e., the electric field near the complex geometry boundaries (plasma grid) is calculated more accurately. The revised model preserves the full 3D treatment, but can take advantage of a highly refined mesh. ONIX was used to investigate the role of the mesh size, the re-injection scheme for lost particles (extracted or wall absorbed), and the electron thermalization process on the calculated extracted current and plasma characteristics. It is demonstrated that all numerical schemes give the same NI current distribution for extracted ions. Concerning the electrons, the pair-injection technique is found well-adapted to simulate the sheath in front of the plasma grid.

Non-destructive fast charging algorithm of lithium-ion batteries based on the control-oriented electrochemical model

International Nuclear Information System (INIS)

Chu, Zhengyu; Feng, Xuning; Lu, Languang; Li, Jianqiu; Han, Xuebing; Ouyang, Minggao

2017-01-01

Highlights: •A novel non-destructive fast charging algorithm of lithium-ion batteries is proposed. •A close-loop observer of lithium deposition status is constructed based on the SP2D model. •The charging current is modified online using the feedback of the lithium deposition status. •The algorithm can shorten the charging time and can be used for charging from different initial SOCs. •The post-mortem observation and degradation tests show that no lithium deposition occurs during fast charging. -- Abstract: Fast charging is critical for the application of lithium-ion batteries in electric vehicles. Conventional fast charging algorithms may shorten the cycle life of lithium-ion batteries and induce safety problems, such as internal short circuit caused by lithium deposition at the negative electrode. In this paper, a novel, non-destructive model-based fast charging algorithm is proposed. The fast charging algorithm is composed of two closed loops. The first loop includes an anode over-potential observer that can observe the status of lithium deposition online, whereas the second loop includes a feedback structure that can modify the current based on the observed status of lithium deposition. The charging algorithm enhances the charging current to maintain the observed anode over-potential near the preset threshold potential. Therefore, the fast charging algorithm can decrease the charging time while protecting the health of the battery. The fast charging algorithm is validated on a commercial large-format nickel cobalt manganese/graphite cell. The results showed that 96.8% of the battery capacity can be charged within 52 min. The post-mortem observation of the surface of the negative electrode and degradation tests revealed that the fast charging algorithm proposed here protected the battery from lithium deposition.

Feature extraction from mammographic images using fast marching methods

International Nuclear Information System (INIS)

Bottigli, U.; Golosio, B.

2002-01-01

Features extraction from medical images represents a fundamental step for shape recognition and diagnostic support. The present work faces the problem of the detection of large features, such as massive lesions and organ contours, from mammographic images. The regions of interest are often characterized by an average grayness intensity that is different from the surrounding. In most cases, however, the desired features cannot be extracted by simple gray level thresholding, because of image noise and non-uniform density of the surrounding tissue. In this work, edge detection is achieved through the fast marching method (Level Set Methods and Fast Marching Methods, Cambridge University Press, Cambridge, 1999), which is based on the theory of interface evolution. Starting from a seed point in the shape of interest, a front is generated which evolves according to an appropriate speed function. Such function is expressed in terms of geometric properties of the evolving interface and of image properties, and should become zero when the front reaches the desired boundary. Some examples of application of such method to mammographic images from the CALMA database (Nucl. Instr. and Meth. A 460 (2001) 107) are presented here and discussed

Fast Monte Carlo for ion beam analysis simulations

International Nuclear Information System (INIS)

Schiettekatte, Francois

2008-01-01

A Monte Carlo program for the simulation of ion beam analysis data is presented. It combines mainly four features: (i) ion slowdown is computed separately from the main scattering/recoil event, which is directed towards the detector. (ii) A virtual detector, that is, a detector larger than the actual one can be used, followed by trajectory correction. (iii) For each collision during ion slowdown, scattering angle components are extracted form tables. (iv) Tables of scattering angle components, stopping power and energy straggling are indexed using the binary representation of floating point numbers, which allows logarithmic distribution of these tables without the computation of logarithms to access them. Tables are sufficiently fine-grained that interpolation is not necessary. Ion slowdown computation thus avoids trigonometric, inverse and transcendental function calls and, as much as possible, divisions. All these improvements make possible the computation of 10 7 collisions/s on current PCs. Results for transmitted ions of several masses in various substrates are well comparable to those obtained using SRIM-2006 in terms of both angular and energy distributions, as long as a sufficiently large number of collisions is considered for each ion. Examples of simulated spectrum show good agreement with experimental data, although a large detector rather than the virtual detector has to be used to properly simulate background signals that are due to plural collisions. The program, written in standard C, is open-source and distributed under the terms of the GNU General Public License

3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map

Science.gov (United States)

Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Franzen, P.; Fantz, U.; Minea, T.

2014-02-01

Decreasing the co-extracted electron current while simultaneously keeping negative ion (NI) current sufficiently high is a crucial issue on the development plasma source system for ITER Neutral Beam Injector. To support finding the best extraction conditions the 3D Particle-in-Cell Monte Carlo Collision electrostatic code ONIX (Orsay Negative Ion eXtraction) has been developed. Close collaboration with experiments and other numerical models allows performing realistic simulations with relevant input parameters: plasma properties, geometry of the extraction aperture, full 3D magnetic field map, etc. For the first time ONIX has been benchmarked with commercial positive ions tracing code KOBRA3D. A very good agreement in terms of the meniscus position and depth has been found. Simulation of NI extraction with different e/NI ratio in bulk plasma shows high relevance of the direct negative ion extraction from the surface produced NI in order to obtain extracted NI current as in the experimental results from BATMAN testbed.

Behavior of the extraction of metallic ions in carbonate medium, using N-benzoylphenylhydroxylamine (BPHA) - benzene

International Nuclear Information System (INIS)

Cipriani, M.

1978-01-01

The possibility of separating quantitatively trace impurities like Cu, Fe, In and Pb, present in uranium base materials of nuclear grade, is demonstrated. A solvent extraction is employed which makes use of -benzoylphenylhydroxylamine(BPHA)-benzene solution and separation is effected in a medium containing 252 moles per liter of sodium-uranyl tricarbonate at pH of 9,0. Carbonate ions under such conditions inhibit uranium extraction by masking uranyl ion-BPHA reaction. The uranyl ions show a demasking action, releasing, thereby, Pb(II) ions which are being extracted from carbonate medium. The Atomic Absorption Spectrophometry technique is used to obtain the experimental data [pt

System upgradation for surface mode negative ion beam extraction experiments in ROBIN

International Nuclear Information System (INIS)

Pandya, Kaushal; Bansal, Gourab; Soni, Jignesh

2015-01-01

ROBIN (Replica Of BATMAN source in India) is a replica of BATMAN source of IPP, Garching. Plasma production (inductively coupled, RF produced plasma), plasma diagnostic (langmuir probe, optical emission spectroscopy), negative ion beam extraction in volume mode with reduced extraction area of 2 cm 2 (4 apertures) using small bench top type power supply (10kV, 400mA), with increase extraction area of 73 cm 2 (146 apertures) and using actual power supplies (Extraction Power Supply System, EPSS (11kV, 35A), and Accelerator Power Supply System, APSS (35kV, 15A)) and beam diagnostic etc have been performed successfully in ROBIN. This paper will describe the details of the system upgradation for surface mode negative ion experiments and its performance in ROBIN

Process and device for the extraction of ions from a clear liquid or one containing matter in suspension with a ion exchanger

International Nuclear Information System (INIS)

Capitani, Enzo; Teissie, Jean.

1982-01-01

Process for the continuous extraction of ions from a clear liquid or one containing matter in suspension by the use of a bed of ion exchange grains which is fluidized inside a column by circulation of the liquid, characterized by the fact that the said bed is subject to cyclic pulsations, in order to obtain sorting of the grains by density, the heavier grains having fixed the maximum ions. This invention can be applied for the continuous extraction of any type of anion or cation or exchangeable salt by means of resins or inorganic exchangers, to avoid clogging and abrasion problems, and to obtain maximum extraction rate and capacity. An example is given of the treatment of a suspension for the extraction of uranium [fr

New experiments in organic, fast-atom-bomdardment, and secondary-ion mass spectrometry

International Nuclear Information System (INIS)

DiDonato, G.C.

1987-01-01

The goal of research presented in this dissertation is the creative use of new ionization and instrumental techniques in mass spectrometry. This goal manifests itself in three areas of mass spectrometry. In the first portion, modern, state-of-the-art instrumentation and new experiments were used to re-examine the mass spectra of transition-metal acetates and acetylacetonates. High resolution, chemical ionization, negative chemical ionization, and extended-mass-range mass spectrometry uncovered a wealth of new gas-phase ionic species. Energy-resolved mass spectrometry/mass spectrometry was applied to the characterization of molecular and fragment ion first-row transition-metal acetylacetonates, and comprises the second portion of the thesis. Studies in fast-atom-bombardment mass spectrometry are the subject of the third portion of the dissertation. Since fast-atom bombardment samples a liquid matrix, absolute and relative abundances of sputtered secondary ions are influenced by solution chemistry. The design and construction of an imaging secondary-ion mass spectrometer is the subject of the final portion of the thesis. This instrument provides for direct mass-spectrometric analysis of thin-layer and paper chromatograms and electrophoretograms

Low-energy ion beam extraction and transport: Experiment--computer comparison

International Nuclear Information System (INIS)

Spaedtke, P.; Brown, I.; Fojas, P.

1994-01-01

Ion beam formation at low energy (∼1 keV or so) is more difficult to accomplish than at high energy because of beam blowup by space-charge forces in the uncompensated region within the extractor, an effect which is yet more pronounced for heavy ions and for high beam current density. For the same reasons, the extracted ion beam is more strongly subject to space charge blowup than higher energy beams if it is not space-charge neutralized to a high degree. A version of vacuum arc ion source with an extractor that produces low-energy metal ion beams at relatively high current (∼0.5--10 kV at up to ∼100 mA) using a multi-aperture, accel--decel extractor configuration has been created. The experimentally observed beam extraction characteristics of this source is compared with those predicted using the AXCEL-INP code, and the implied downstream beam transport with theoretical expectations. It is concluded that the low-energy extractor performance is in reasonable agreement with the code, and that good downstream space charge neutralization is obtained. Here, the code and the experimental results are described, and the features that contribute to good low-energy performance are discussed

Fast ion generation by a picosecond high-power laser

Czech Academy of Sciences Publication Activity Database

Badziak, J.; Parys, P.; Wolowski, J.; Hora, H.; Krása, Josef; Láska, Leoš; Rohlena, Karel

2005-01-01

Roč. 35, č. 1 (2005), s. 5-22 ISSN 0078-5466 R&D Projects: GA MŠk(CZ) ME 238 Grant - others:International Atomic Energy in Vienna(XE) 11535/RO; State Commitee for Scientific Research (KBN)(PL) 1 PO3B 082 19 and 1 PO3B 043 26 Institutional research plan: CEZ:AV0Z10100523 Keywords : fast ion * plasma * picosecond laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.459, year: 2005

Parasitic excitation of ion Bernstein waves from a Faraday shielded fast wave loop antenna

International Nuclear Information System (INIS)

Skiff, F.; Ono, M.; Colestock, P.; Wong, K.L.

1984-12-01

Parasitic excitation of ion Bernstein waves is observed from a Faraday shielded fast wave loop antenna in the ion cyclotron frequency range. Local analysis of the Vlasov-Maxwell equations demonstrates the role of plasma density gradient in the coupling process. The effects of plasma density and of parallel wave number on the excitation process are investigated

Damage cross sections for fast heavy ion induced desorption of biomolecules

Energy Technology Data Exchange (ETDEWEB)

Salehpour, M; Hakansson, P; Sundqvist, B [Uppsala Univ. (Sweden). Tandem Accelerator Lab.

1984-03-01

The Uppsala EN-tandem accelerator combined with a time-of-flight mass spectrometer has been used to measure the damage cross sections for Fast Heavy Ion Induced Desorption (FHIID) of the amino acid valine (MW=117) and the protein bovine insulin (MW=5733). Time-of-flight spectra have been obtained after exposing the sample to a known radiation dose of 90 MeV /sup 127/I/sup 14 +/ ions and the yield of the quasi-molecular ions has been measured as a function of the radiation dose. The results are: 6.8(+-1.8)x10/sup -13/ cm/sup 2/ and 50(+-17)x10/sup -13/ cm/sup 2/ for positive ions of valine and insulin respectively. The cross section for valine is roughly one order of magnitude larger than previously published low energy (keV) damage cross sections for the amino acid leucine.

Analysis methods for fast impurity ion dynamics data

International Nuclear Information System (INIS)

Den Hartog, D.J.; Almagri, A.F.; Prager, S.C.; Fonck, R.J.

1994-08-01

A high resolution spectrometer has been developed and used on the MST reversed-field pinch (RFP) to measure passively impurity ion temperatures and flow velocities with 10 μs temporal resolution. Such measurements of MHD-scale fluctuations are particularly relevant in the RFP because the flow velocity fluctuation induced transport of current (the ''MHD dynamo'') may produce the magnetic field reversal characteristic of an RFP. This instrument will also be used to measure rapid changes in the equilibrium flow velocity, such as occur during locking and H-mode transition. The precision of measurements made to date is <0.6 km/s. The authors are developing accurate analysis techniques appropriate to the reduction of this fast ion dynamics data. Moment analysis and curve-fitting routines have been evaluated for noise sensitivity and robustness. Also presented is an analysis method which correctly separates the flux-surface average of the correlated fluctuations in u and B from the fluctuations due to rigid shifts of the plasma column

Fast filtration sampling protocol for mammalian suspension cells tailored for phosphometabolome profiling by capillary ion chromatography - tandem mass spectrometry.

Science.gov (United States)

Kvitvang, Hans F N; Bruheim, Per

2015-08-15

Capillary ion chromatography (capIC) is the premium separation technology for low molecular phosphometabolites and nucleotides in biological extracts. Removal of excessive amounts of salt during sample preparation stages is a prerequisite to enable high quality capIC separation in combination with reproducible and sensitive MS detection. Existing sampling protocols for mammalian cells used for GC-MS and LC-MS metabolic profiling can therefore not be directly applied to capIC separations. Here, the development of a fast filtration sampling protocol for mammalian suspension cells tailored for quantitative profiling of the phosphometabolome on capIC-MS/MS is presented. The whole procedure from sampling the culture to transfer of filter to quenching and extraction solution takes less than 10s. To prevent leakage it is critical that a low vacuum pressure is applied, and satisfactorily reproducibility was only obtained by usage of a vacuum pressure controlling device. A vacuum of 60mbar was optimal for filtration of multiple myeloma Jjn-3 cell cultures through 5μm polyvinylidene (PVDF) filters. A quick deionized water (DI-water) rinse step prior to extraction was tested, and significantly higher metabolite yields were obtained during capIC-MS/MS analyses in this extract compared to extracts prepared by saline and reduced saline (25%) washing steps only. In addition, chromatographic performance was dramatically improved. Thus, it was verified that a quick DI-water rinse is tolerated by the cells and can be included as the final stage during filtration. Over 30 metabolites were quantitated in JJN-3 cell extracts by using the optimized sampling protocol with subsequent capIC-MS/MS analysis, and up to 2 million cells can be used in a single filtration step for the chosen filter and vacuum pressure. The technical set-up is also highly advantageous for microbial metabolome filtration protocols after optimization of vacuum pressure and washing solutions, and the reduced salt

Synergistic Effect of Azadirachta Indica Extract and Iodide Ions on the Corrosion Inhibition of Aluminium in Acid Media

Energy Technology Data Exchange (ETDEWEB)

Arab, S. T.; Al- Turkustani, A. M.; Al- Dhahiri, R. H. [King Abd El- Aziz University, Jeddah (Saudi Arabia)

2008-06-15

The synergistic action caused by iodide ions on the corrosion inhibition of aluminium (Al) in 0.5 M HCl in the presence of Azadirachta Indica (AZI) plant extract has been investigated using potintiodynamic polarization and impedance techniques. It is found that AZI extract inhibits the corrosion of aluminium in 0.5 M HCl. The inhibition efficiency increases with the increase in AZI extract concentration, until 24% v/v of AZI extract, then Inh.% is decreased with father increase in AZI extract concentration. The adsorption of this extract in the studied concentration is found to obey Frewendlish adsorption isotherm. The addition of iodide ions enhances the inhibition efficiency to a considerable extent. The increase in Inh.% values in presence of fixed concentration of iodide ions indicates that AZI extract forms an insoluble complex at lower AZI extract concentrations by undergoing a joint adsorption. But at higher concentrations of AZI extract, competitive adsorption is found between iodide ions and the formed complex leading to less Inh.%. The Inh.% decreased in presence of iodide ions with AZI extract than in presence of AZI extract alone at all studied iodide concentrations. The synergism parameter S {sub θ} is defined and calculated from surface coverage values. This parameter in the case of AZI extract is found to be more than unity, indicating that the enhanced inhibition efficiency caused by the addition of iodide ions.

Portable test bench for the studies concerning ion sources and ion beam extraction and focusing systems

International Nuclear Information System (INIS)

Cordero Lopez, F.

1961-01-01

A portable test bench is described, which was designed to check ion sources, ion beam extraction and focusing systems before its use in a 600 KeV Cockcroft-Walton accelerator. The vacuum possibilities of the system are specially analyzed in connection with its particular use. The whole can be considered as a portable accelerator of low energy (50 keV). (Author)

Asymptotic analysis of an ion extraction model

International Nuclear Information System (INIS)

Ben Abdallah, N.; Mas-Gallic, S.; Raviart, P.A.

1993-01-01

A simple model for ion extraction from a plasma is analyzed. The order of magnitude of the plasma parameters leads to a singular perturbation problem for a semilinear elliptic equation. We first prove existence of solutions for the perturbed problem and uniqueness under certain conditions. Then we prove the convergence of these solutions, when the parameters go to zero, towards the solution of a Child-Langmuir problem

Advanced integrated solvent extraction and ion exchange systems

International Nuclear Information System (INIS)

Horwitz, P.

1996-01-01

Advanced integrated solvent extraction (SX) and ion exchange (IX) systems are a series of novel SX and IX processes that extract and recover uranium and transuranics (TRUs) (neptunium, plutonium, americium) and fission products 90 Sr, 99 Tc, and 137 Cs from acidic high-level liquid waste and that sorb and recover 90 Sr, 99 Tc, and 137 Cs from alkaline supernatant high-level waste. Each system is based on the use of new selective liquid extractants or chromatographic materials. The purpose of the integrated SX and IX processes is to minimize the quantity of waste that must be vitrified and buried in a deep geologic repository by producing raffinates (from SX) and effluent streams (from IX) that will meet the specifications of Class A low-level waste

Collisions of fast multicharged ions in gas targets: charge transfer and ionization

International Nuclear Information System (INIS)

Schlachter, A.S.

1981-05-01

Measurements of cross sections for charge transfer and ionization of H 2 and rare-gas targets have been made with fast, highly stripped projectiles in charge states as high as 59+. We have found an empirical scaling rule for electron-capture cross section in H 2 valid at energies above 275 keV/amu. Similar scaling might exist for other target gases. Cross sections are generally in good agreement with theory. We have found a scaling rule for electron loss from H in collisions with a fast highly stripped projectile, based on Olson's classical-trajectory Monte-Carlo calculations, and confirmed by measurements in an H 2 target. We have found a similar scaling rule for net ionization of rare-gas targets, based on Olson's CTMC calculations and the independent-electron model. Measurements are essentially consistent with the scaled cross sections. Calculations and measurements of recoil-ion charge-state spectra show large cross sections for the production of highly charged slow recoil ions

Fast Beam-ion Instabilities in CLIC Main Linac Vacuum Specifications

CERN Document Server

Oeftiger, Adrian

2011-01-01

Specifications for the vacuum pressure in the CLIC electron Main Linac are determined by the onset of the fast beam-ion instability (FBII). When the electron beam is accelerated in the Main Linac, it ionizes the residual gas in the chamber through scattering ionization. If the density of ions around the beam exceeds a certain threshold, a resonant motion between the electron beam and the ions can be excited. A two-stream instability appears and as a result the beam acquires a coherent motion, which can quickly lead to beam quality degradation or even complete loss. Thus, the vacuum pressure must be kept below this threshold to prevent the excitation of FBII. The CLIC Main Linac poses an additional challenge with respect to previous FBII situations, because the gas ionization does not solely occur via scattering. The submicrometric beam sizes lead to extremely high electric fields around the beam and therefore result in field ionization beyond a certain threshold. The residual gas in the corresponding volume a...

Investigation of metal ion extraction and aggregate formation combining acidic and neutral organophosphorous reagents

Energy Technology Data Exchange (ETDEWEB)

Braatz, A.D.; Nilsson, M. [Department of Chemical Engineering and Materials Science, 916 Engineering Tower, University of California-Irvine, Irvine, CA 92697-2575 (United States); Ellis, R.; Antonio, M. [Chemical Science and Engineering Division, Argonne National Laboratory, Building 200 9700 South Cass Ave, Argonne, IL 60439-4831 (United States)

2013-07-01

In the present study, we investigate how varying mixtures of tri-n-butyl phosphate (TBP) and dibutyl phosphate (HDBP) results in enhanced extraction of lanthanum(III), La{sup 3+}, and dysprosium(III), Dy{sup 3+}. Water and metal ion extraction were carefully monitored as a function of TBP:HDBP mole ratio.In addition to these techniques, EXAFS was used to determine the coordination environment of the metal ion in this system. To produce the necessary signal, a concentration of 1.25*10{sup -3} M La{sup 3+} and Dy{sup 3+} was used. Although previous studies of synergistic extraction of metal cations using combinations of neutral and acidic reagents explain the enhanced extraction by increased dehydration of the metal ion and the formation of mixed extractant complexes, our evidence for the increased water extraction coupled with the aggregate formation suggests a reverse micellar aspect to synergism in the system containing TBP and HDBP. It is quite possible that both of these phenomena contribute to our system behavior. The EXAFS data shows that, based on coordination numbers alone, several possible structures may exist. From this study, we cannot provide a definitive answer as to the nature of extraction in this system or the exact complex formed during extraction.

The transmission of fast molecular ions through thin foils

International Nuclear Information System (INIS)

Pietsch, W.J.; Gemmell, D.S.; Cooney, P.J.; Kanter, E.P.; Kurath, D.; Ratkowski, A.J.; Vager, Z.; Zabransky, B.J.

1980-01-01

We present new results on the transmission of fast molecular ions through thin foils and propose a mechanism for the transmission process. The main feature of the postulated mechanism is that a finite fraction of the incident molecular beam does not undergo a strong Coulomb explosion while traversing the foil. Because the emerging fragments are at large internuclear separations, there is an enhanced probability for the formation of bound, long-range, excited electronic states following electron capture at the rear surface of the target. (orig.)

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

International Nuclear Information System (INIS)

Gueroult, R.

2011-09-01

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

Modeling of negative ion extraction from a magnetized plasma source: Derivation of scaling laws and description of the origins of aberrations in the ion beam

Science.gov (United States)

Fubiani, G.; Garrigues, L.; Boeuf, J. P.

2018-02-01

We model the extraction of negative ions from a high brightness high power magnetized negative ion source. The model is a Particle-In-Cell (PIC) algorithm with Monte-Carlo Collisions. The negative ions are generated only on the plasma grid surface (which separates the plasma from the electrostatic accelerator downstream). The scope of this work is to derive scaling laws for the negative ion beam properties versus the extraction voltage (potential of the first grid of the accelerator) and plasma density and investigate the origins of aberrations on the ion beam. We show that a given value of the negative ion beam perveance correlates rather well with the beam profile on the extraction grid independent of the simulated plasma density. Furthermore, the extracted beam current may be scaled to any value of the plasma density. The scaling factor must be derived numerically but the overall gain of computational cost compared to performing a PIC simulation at the real plasma density is significant. Aberrations appear for a meniscus curvature radius of the order of the radius of the grid aperture. These aberrations cannot be cancelled out by switching to a chamfered grid aperture (as in the case of positive ions).

Ion-pair extraction of [3]histobadine from biological fluids

International Nuclear Information System (INIS)

Scasnar, V.

1997-01-01

A simple and specific radiometric assay was developed for determination of stobadine, a cardio protective drug, in the serum of experimental animals. It is based on a single extraction step of the radioactively labeled drug from serum into the benzene solution of dicarbolide of cobalt followed by the quantitation of the extracted radioactivity by using liquid scintillation counting. The extraction mechanism involves the ion-pair formation between the protonized molecule of stobadine and the hydrophobic, negatively charged molecule of dicarbollide of cobalt. The extraction of yield of stobadine from 1 ml of serum was 95% in the concentration range from 1 to 6000 ng/ml. The co extraction of metabolites was less than 5%. The assay was applied to determination of stobadine in serum of dogs and the data obtained were in good agreement with those obtained by high performance liquid chromatography. (author)

Microwave plasma source having improved switching operation from plasma ignition phase to normal ion extraction phase

International Nuclear Information System (INIS)

Sakudo, N.; Abe, K.; Koike, H.; Okada, O.; Tokiguchi, K.

1985-01-01

In a microwave plasma source, a discharge space supplied with a microwave electric field is supplied with a DC magnetic field. A material to be ionized is introduced into the discharge space to produce plasma, whereby ions are extracted through an ion extracting system. A switch is provided for effecting through switching operation the change-over of the magnetic field applied to the discharge space from the intensity for the ignition of plasma to the intensity for ion extraction in succession to completion of the plasma ignition

QUANTITATIVE ION-PAIR EXTRACTION OF 4(5)-METHYLIMIDAZOLE FROM CARAMEL COLOR AND ITS DETERMINATION BY REVERSED-PHASE ION-PAIR LIQUID-CHROMATOGRAPHY

DEFF Research Database (Denmark)

Thomsen, Mohens; Willumsen, Dorthe

1981-01-01

A procedure for quantitative ion-pair extraction of 4(5)-methylimidazole from caramel colour using bis(2-ethylhexyl)phosphoric acid as ion-pairing agent has been developed. Furthermore, a reversed-phase ion-pair liquid chromatographic separation method has been established to analyse the content...

Semiclassical eigenenergies in the wake of fast ions in solids

International Nuclear Information System (INIS)

Mueller, J.; Burgdoerfer, J.; Noid, D.W.

1990-01-01

We compare the semiclassical and quantum mechanical eigenenergies of an electron in the wake of a fast, highly charged ion traversing a solid. The classical dynamics of this system shows a transition from regular to chaotic motion as a function of the binding energy. The transition can also be seen in the quantal spectra. We find evidence for a connection between bifurcation of tori and disorder in the energy level sequences. 21 refs., 4 figs

Forging Fast Ion Conducting Nanochannels with Swift Heavy Ions: The Correlated Role of Local Electronic and Atomic Structure

Energy Technology Data Exchange (ETDEWEB)

Sachan, Ritesh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Material Science and Technology Division; Cooper, Valentino R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Material Science and Technology Division; Liu, Bin [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Aidhy, Dilpuneet S. [Univ. of Wyoming, Laramie, WY (United States). Dept. of Mechanical Engineering; Voas, Brian K. [Iowa State Univ., Ames, IA (United States). Dept. of Materials Science and Engineering; Lang, Maik [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Nuclear Engineering; Ou, Xin [Chinese Academy of Sciences (CAS), Shanghai (China). State Key Lab. of Functional Material for Informatics; Trautmann, Christina [GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Technical Univ. of Darmstadt (Germany). Dept. of Materials Science; Zhang, Yanwen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Material Science and Technology Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Chisholm, Matthew F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Material Science and Technology Division; Weber, William J. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Material Science and Technology Division

2016-12-19

Atomically disordered oxides have attracted significant attention in recent years due to the possibility of enhanced ionic conductivity. However, the correlation between atomic disorder, corresponding electronic structure, and the resulting oxygen diffusivity is not well understood. The disordered variants of the ordered pyrochlore structure in gadolinium titanate (Gd₂Ti₂O₇) are seen as a particularly interesting prospect due to intrinsic presence of a vacant oxygen site in the unit atomic structure, which could provide a channel for fast oxygen conduction. In this paper, we provide insights into the subangstrom scale on the disordering-induced variations in the local atomic environment and its effect on the electronic structure in high-energy ion irradiation-induced disordered nanochannels, which can be utilized as pathways for fast oxygen ion transport. With the help of an atomic plane-by-plane-resolved analyses, the work shows how the presence of various types of TiO_x polyhedral that exist in the amorphous and disordered crystalline phase modify the electronic structures relative to the ordered pyrochlore phase in Gd₂Ti₂O₇. Finally, the correlated molecular dynamics simulations on the disordered structures show a remarkable enhancement in oxygen diffusivity as compared with ordered pyrochlore lattice and make that a suitable candidate for applications requiring fast oxygen conduction.

Elastic wave from fast heavy ion irradiation on solids

CERN Document Server

Kambara, T; Kanai, Y; Kojima, T M; Nanai, Y; Yoneda, A; Yamazaki, Y

2002-01-01

To study the time-dependent mechanical effects of fast heavy ion irradiations, we have irradiated various solids by a short-bunch beam of 95 MeV/u Ar ions and observed elastic waves generated in the bulk. The irradiated targets were square-shaped plates of poly-crystals of metals (Al and Cu), invar alloy, ceramic (Al sub 2 O sub 3), fused silica (SiO sub 2) and single crystals of KC1 and LiF with a thickness of 10 mm. The beam was incident perpendicular to the surface and all ions were stopped in the target. Two piezo-electric ultrasonic sensors were attached to the surface of the target and detected the elastic waves. The elastic waveforms as well as the time structure and intensity of the beam bunch were recorded for each shot of a beam bunch. The sensor placed opposite to the beam spot recorded a clear waveform of the longitudinal wave across the material, except for the invar and fused silica targets. From its propagation time along with the sound velocity and the thickness of the target, the depth of the...

Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

Science.gov (United States)

Toivanen, V; Küchler, D

2016-02-01

The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

Contribution to the study of liquid-liquid extraction dynamics in the case of fast transfers. Extractions of uranium, plutonium and neptunium in a laboratory centrifugal extractor

International Nuclear Information System (INIS)

Bergeonneau, Philippe

1978-01-01

The liquid-liquid extraction (also named solvent-based extraction) is a very important technique for the reprocessing of irradiated nuclear fuels. This research thesis is based on the use of a laboratory centrifugal extractor which allows interesting conditions to be achieved: fast transfer due to an intense solution mixing, very short duration of contact between solutions. Thus, after a report of a bibliographical study on chemical mechanisms of extraction, on the composition of extracted species, on extraction kinetics, and on centrifugal extractors, this thesis reports the design, fabrication and use of a centrifugal extractor: presentation of fundamental principles, description and characteristics (materials, hydrodynamic operation test and problems, prototype). It reports studies of fast transfer kinetics: mathematical processing, result interpretation, results and discussions of extraction kinetics for nitric acid, uranium VI and IV, plutonium IV, neptunium IV, and comparison of the different extraction kinetics

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

Monte-Carlo Orbit/Full Wave Simulation of Fast Alfven Wave (FW) Damping on Resonant Ions in Tokamaks

International Nuclear Information System (INIS)

Choi, M.; Chan, V.S.; Pinsker, R.I.; Tang, V.; Bonoli, P.; Wright, J.

2005-01-01

To simulate the resonant interaction of fast Alfven wave (FW) heating and Coulomb collisions on energetic ions, including finite orbit effects, a Monte-Carlo code ORBIT-RF has been coupled with a 2D full wave code TORIC4. ORBIT-RF solves Hamiltonian guiding center drift equations to follow trajectories of test ions in 2D axisymmetric numerical magnetic equilibrium under Coulomb collisions and ion cyclotron radio frequency quasi-linear heating. Monte-Carlo operators for pitch-angle scattering and drag calculate the changes of test ions in velocity and pitch angle due to Coulomb collisions. A rf-induced random walk model describing fast ion stochastic interaction with FW reproduces quasi-linear diffusion in velocity space. FW fields and its wave numbers from TORIC are passed on to ORBIT-RF to calculate perpendicular rf kicks of resonant ions valid for arbitrary cyclotron harmonics. ORBIT-RF coupled with TORIC using a single dominant toroidal and poloidal wave number has demonstrated consistency of simulations with recent DIII-D FW experimental results for interaction between injected neutral-beam ions and FW, including measured neutron enhancement and enhanced high energy tail. Comparison with C-Mod fundamental heating discharges also yielded reasonable agreement

Formation of Rydberg states in fast ion-atom collisions

International Nuclear Information System (INIS)

Schneider, D.; Kanter, E.P.; Vager, Z.; Gemmell, D.; Koch, P.; Mariani, D.; Van de Water, W.

1983-01-01

Previous results from beam-foil spectroscopy and from experiments using field ionization techniques have shown that a significant fraction of fast ionic projectiles traversing solid targets can be excited to high Rydberg states. We report an experimental investigation of Rydberg states formed in atomic and molecular ion beams (MeV) emerging from thin-carbon foils. Different field arrangements, including μ-wave fields, have been applied to study the effects of field ionization. The yields of electrons produced via field ionization are compared for different projectile atoms and molecules

Extraction of volume produced H- or D- ions from a sheet plasma, 2

International Nuclear Information System (INIS)

Uramoto, Joshin.

1984-02-01

A development to large area H - or D - ion source is tried by using three extraction electrodes: The first electrode bias voltage is set near the wall potential (floating), the second electrode is set near 13 % of main extraction voltage and the third electrode is the main acceleration electrode. An ion current of 13 mA (3.3 mA/cm 2 ) for H - or 11 mA (2.8 mA/ cm 2 ) for D - at 3 KeV is extracted from 9 apertures of 6 mm phi in 4 cm 2 outside of the sheet plasma (14 cm wide and 1.0 cm thick) under a pressure of 7.7 x 10 -4 H2 or D2 gas and a weak magnetic field 50 gauss. Then, it is noted that the corresponding electron current is suppressed below 1/10 of the H - or D - ion current. (author)

Fast-ion transport in low density L-mode plasmas at TCV using FIDA spectroscopy and the TRANSP code

DEFF Research Database (Denmark)

Geiger, B.; Karpushov, A.; Duval, B. P.

2017-01-01

Experiments with the new neutral beam injection source of TCV have been performed with high fast-ion fractions (>20%) that exhibit a clear reduction of the loop voltage and a clear increase of the plasma pressure in on- and off-axis heating configurations. However, good quantitative......, a newly installed fast-ion D-alpha (FIDA) spectroscopy system measures strong passive radiation and, hence, indicates the presence of high background neutral densities such that charge-exchange losses are substantial. Also the active radiation measured with the FIDA diagnostic, as well as data from...... a neutral particle analyzer, suggest strong fast-ion losses and large neutral densities. The large neutral densities can be justified since high electron temperatures (3–4 keV), combined with low electron densities (about 2 X 1019 m−3) yield long mean free paths of the neutrals which are penetrating from...

A fast, simple and green method for the extraction of carbamate pesticides from rice by microwave assisted steam extraction coupled with solid phase extraction.

Science.gov (United States)

Song, Weitao; Zhang, Yiqun; Li, Guijie; Chen, Haiyan; Wang, Hui; Zhao, Qi; He, Dong; Zhao, Chun; Ding, Lan

2014-01-15

This paper presented a fast, simple and green sample pretreatment method for the extraction of 8 carbamate pesticides in rice. The carbamate pesticides were extracted by microwave assisted water steam extraction method, and the extract obtained was immediately applied on a C18 solid phase extraction cartridge for clean-up and concentration. The eluate containing target compounds was finally analysed by high performance liquid chromatography with mass spectrometry. The parameters affecting extraction efficiency were investigated and optimised. The limits of detection ranging from 1.1 to 4.2ngg(-1) were obtained. The recoveries of 8 carbamate pesticides ranged from 66% to 117% at three spiked levels, and the inter- and intra-day relative standard deviation values were less than 9.1%. Compared with traditional methods, the proposed method cost less extraction time and organic solvent. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quantitative Analysis of Tenofovir by Titrimetric, Extractive Ion-pair ...

African Journals Online (AJOL)

Methods: Tenofovir disoproxil forms a complex of 1:1 molar ratio with fumaric acid that was employed in its aqueous titration with sodium hydroxide. Non-aqueous titration was also employed for its determination. Extractive ion-pair spectrophotometric technique using methyl orange was similarly employed to evaluate ...

Detection of nitro-based and peroxide-based explosives by fast polarity-switchable ion mobility spectrometer with ion focusing in vicinity of Faraday detector.

Science.gov (United States)

Zhou, Qinghua; Peng, Liying; Jiang, Dandan; Wang, Xin; Wang, Haiyan; Li, Haiyang

2015-05-29

Ion mobility spectrometer (IMS) has been widely deployed for on-site detection of explosives. The common nitro-based explosives are usually detected by negative IMS while the emerging peroxide-based explosives are better detected by positive IMS. In this study, a fast polarity-switchable IMS was constructed to detect these two explosive species in a single measurement. As the large traditional Faraday detector would cause a trailing reactant ion peak (RIP), a Faraday detector with ion focusing in vicinity was developed by reducing the detector radius to 3.3 mm and increasing the voltage difference between aperture grid and its front guard ring to 591 V, which could remove trailing peaks from RIP without loss of signal intensity. This fast polarity-switchable IMS with ion focusing in vicinity of Faraday detector was employed to detect a mixture of 10 ng 2,4,6-trinitrotoluene (TNT) and 50 ng hexamethylene triperoxide diamine (HMTD) by polarity-switching, and the result suggested that [TNT-H](-) and [HMTD+H](+) could be detected in a single measurement. Furthermore, the removal of trailing peaks from RIP by the Faraday detector with ion focusing in vicinity also promised the accurate identification of KClO4, KNO3 and S in common inorganic explosives, whose product ion peaks were fairly adjacent to RIP.

Fast ion profiles during neutral beam and lower hybrid heating

International Nuclear Information System (INIS)

Heidbrink, W.W.; Strachan, J.D.; Bell, R.E.; Cavallo, A.; Motley, R.; Schilling, G.; Stevens, J.; Wilson, J.R.

1985-07-01

Profiles of the d(d,p)t fusion reaction are measured in the PLT tokamak using an array of collimated 3 MeV proton detectors. During deuterium neutral beam injection, the emission profile indicates that the beam deposition is at least as narrow as predicted by a bounce-averaged Fokker-Planck code. The fast ion tail formed by lower hybrid waves (at densities above the critical density for current drive) also peaks strongly near the magnetic axis

The fast extraction kicker power supply for the main ring of J-PARC

Energy Technology Data Exchange (ETDEWEB)

Koseki, Kunio, E-mail: kunio.koseki@kek.jp

2013-11-21

An effect induced by parasitic inductance in a pulsed power supply for a fast extraction kicker was studied. The parasitic inductance in high voltage capacitors for a low impedance pulse forming network disturbs a sharp rise of an excitation current. A high voltage capacitor with a coaxial structure to minimize the parasitic inductance is proposed. The effectiveness was confirmed experimentally. An impedance mismatch by a leakage inductance of a pulse transformer in a transmission line was studied. The effect is serious at the flat-top period of the excitation current. By introducing a compensation circuit, which is composed by a capacitor and a resistor, impedance matching was established. The pulsed power supply for the fast extraction kicker was operated at a charging voltage of 30 kV. A required rise time of less than 1.1 μs was achieved. The flatness was also confirmed to be in an acceptable value of less than 1%. -- Highlights: ●An effect by parasitic inductance of the energy storage capacitor of the PFN was studied. ●A faster rise time was achieved by introducing a coaxial structure for the PFN capacitor. ●An impedance mismatch by a leakage inductance of a pulse transformer was studied. ●Serious deterioration of the pulsed waveform was cured by a compensation circuit. ●The pulsed power supply for the fast extraction kicker was developed and operated successfully.

Isolation of nitrosylruthenium nitrato complexes by ion exchange and extraction chromatography

International Nuclear Information System (INIS)

Huang, H.; Liu, L.

TBP Levextrel and cation exchange resins were used to separate RuNO nitrato complexes of different nitric acid concentrations. 7402 quaternary ammonium salt Levextrel was used instead of an anionic exchange resin to separate anionic and neutral complex ions. The results indicated that D 3 and D 4 , which can easily be extracted by TBP, were anionic and neutral complex ions

Experimental studies of fast deuterons, impurity- and admixture-ions emitted from a plasma focus

International Nuclear Information System (INIS)

Mozer, A.; Sadowski, M.; Herold, H.; Schmidt, H.

1982-01-01

The energy and mass analysis of ions emitted from a 50-kJ, 18-kV, plasma focus machine was performed with a Thomson analyzer. Energy distribution functions of fast deuterons (E> or =350 keV) and those of impurity ions have been determined. The energy distributions of the O, N, and C impurity ions in different ionization states have similar character. They usually increase exponentially and after reaching the maximum at E/Zroughly-equal1.0 MeV they decrease exponentially to E/Zroughly-equal1.8 MeV. For deuterons at lower operating pressures (p 0 + -Ar 7+ ions of energy from 0.5 to 14 MeV are produced

Electrostatic instabilities, turbulence and fast ion interactions in the TORPEX device

Energy Technology Data Exchange (ETDEWEB)

Fasoli, A; Burckel, A; Federspiel, L; Furno, I; Gustafson, K; Iraji, D; Labit, B; Loizu, J; Plyushchev, G; Ricci, P; Theiler, C [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Diallo, A; Podesta, M [Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States); Mueller, S H [Center for Energy Research, University of California, San Diego, CA 92093 (United States); Poli, F [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL (United Kingdom)

2010-12-15

Electrostatic turbulence, related structures and their effect on particle, heat and toroidal momentum transport are investigated in TORPEX simple magnetized plasmas using high-resolution diagnostics, control parameters, linear fluid models and nonlinear numerical simulations. The nature of the dominant instabilities is controlled by the value of the vertical magnetic field, B{sub v}, relative to that of the toroidal field, B{sub T}. For B{sub v}/B{sub T} > 3%, only ideal interchange instabilities are observed. A critical pressure gradient to drive the interchange instability is experimentally identified. Interchange modes give rise to blobs, radially propagating filaments of enhanced plasma pressure. Blob velocities and sizes are obtained from electrostatic probe measurements using pattern recognition methods. The observed values span a wide range and are described by a single analytical expression, from the small blob size regime in which the blob velocity is limited by cross-field ion polarization currents, to the large blob size regime in which the limitation to the blob velocity comes from parallel currents to the sheath. As a first attempt at controlling the blob dynamical properties, limiter configurations with varying angles between field lines and the conducting surface of the limiter are explored. Mach probe measurements clearly demonstrate a link between toroidal flows and blobs. To complement probe data, a fast framing camera and a movable gas puffing system are installed. Density and light fluctuations show similar signatures of interchange activity. Further developments of optical diagnostics, including an image intensifier and laser-induced fluorescence, are under way. The effect of interchange turbulence on fast ion phase space dynamics is studied using movable fast ion source and detector in scenarios for which the development from linear waves into blobs is fully characterized. A theory validation project is conducted in parallel with TORPEX

Influence of sawtooth oscillations of fast ion spatial distribution

International Nuclear Information System (INIS)

Anderson, D.; Lisak, M.; Wising, F.

1992-01-01

Recent measurements of global as well as line integrated neutron emission generated during NBI heating on JET have provided significant information on the influence of sawtooth oscillations on injected ions. The measurements have been analysed tomographically to deduce the spatial distribution of the neutron emission before and after the sawtooth crash, and the results indicate that the fast ions are expelled from the plasma core during crashes. The present report summarizes the theoretical work performed within the JET contract JTI/13435, the final aim of which is to try to interpret the mentioned experimental results. The analysis involves analytical as well as numerical calculations. A new model of sawtooth crashes with q o below unity is presented, based on the models of Kadomtsev and Wesson. The analytical results for the changes in global and local neutron emissivity at the sawtooth crash are in qualitative agreement with experimental results. The new model predicts stronger redistribution of the neutron emissivity, but a smaller change of global emissivity than the Kadomtsev model. A detailed numerical investigation of the sawtooth induced change in neutron emissivity is also made. The Fokker-Planck equation is used to calculate the distribution function of the injected fast ions before the crash and the models are used to find the change of both beam and plasma parameters due to the crash. The radial distributions of the neutron emissivity before and after the crash are then calculated and used for integration along the lines-of-sight of the neutron profile monitor on JET. The flux surface geometry obtained from MHD equilibrium calculations is used during the integration. In addition, the change of the global neutron emission is also calculated and compared with experimental results. Both the Kadomtsev model and the model suggested here are found to be consistent with the experimentally observed change in neutron emissivity provided the q(r)-profile is

Acceleration of the Fast Solar Wind through Minor Ions

Science.gov (United States)

Li, X.

2004-01-01

It is assumed that the magnetic flux tubes are strongly concentrated at the boundaries of the supergranule convection cells. A power law spectrum of high frequency Alfvén waves with a spectral index -1 originating from the sun is assumed to supply all the energy needed to energize the plasma flowing in such magnetic flux tubes. At the high frequency end, the waves are eroded by ions due to ion cyclotron resonance. The magnetic flux concentration is essential since it allows a sufficiently strong energy flux to be carried by high frequency ion cyclotron waves and these waves can be readily released at the coronal base by cyclotron resonance. The main results are: 1. By primarily heating alpha particles only, it is possible to produce a steep transition region, a hot corona and a fast solar wind. Coulomb coupling plays a key role in transferring the thermal energy of alpha particles to protons and electrons at the corona base. The electron thermal conduction then does the remaining job to create a sharp transition region. 2. Plasma species may already partially lose thermal equilibrium in the transition region, minor ions may already be faster than protons at the very bottom of the corona. 3. The model predicts high temperature alpha particles (T 2 × 107 K) and low proton temperatures (Tp solar radii, suggests that hydrogen Lyman lines observed by UVCS above coronal holes may be primarily broadened by Alfvén waves in this range.

Causes and cures for errors in the simulation of ion extraction from plasmas

International Nuclear Information System (INIS)

Becker, R.

2006-01-01

For many years, computer programs have been available to simulate the extraction of positive ions from plasmas. The results of such simulations may not always agree with measurements. There are different reasons for this: the mathematical formulation must match with the simulated physics, the number of meshes must be high enough to correctly take into account the nonlinear space charge in the sheath, and ray tracing must be done in sufficiently small steps, using numerically correct field components and partial derivatives. In addition to these hidden problems the user may create errors by a wrong choice of parameters, which are not matching the assumptions of the mathematical formulation. Examples are the use of a positive ion extraction program for the extraction of negative ones, the choice of a wrong angle between the plasma electrode and the beam boundary in the vicinity of the meniscus, and the use of too few trajectories. The design of extraction electrodes generally has the aim to optimize the optical properties and the current of the ion beam. However, it is also important to take into account the surface fields in order to avoid dark currents and sparking

Extraction of highly charged ions from the Berlin Electron Beam Ion Trap for interactions with a gas target

International Nuclear Information System (INIS)

Allen, F.I.; Biedermann, C.; Radtke, R.; Fussmann, G.

2006-01-01

Highly charged ions are extracted from the Berlin Electron Beam Ion Trap for investigations of charge exchange with a gas target. The classical over-the-barrier model for slow highly charged ions describes this process, whereby one or more electrons are captured from the target into Rydberg states of the ion. The excited state relaxes via a radiative cascade of the electron to ground energy. The cascade spectra are characteristic of the capture state. We investigate x-ray photons emitted as a result of interactions between Ar 17+ ions at energies ≤5q keV with Ar atoms. Of particular interest is the velocity dependence of the angular momentum capture state l c

Doppler-shift assisted fast ion spectroscopy: a case study for X-ray emission from 277 MeV/u Pb[81+] ions

International Nuclear Information System (INIS)

Mokler, P.H.; Stoehlker, T.; Kozhuharov, C.; Moshammer, R.; Rymuza, P.; Stachura, Z.; Warczak, A.

1994-09-01

Utilizing the different information from spatially separated segments of high-granular photon detectors the measured (LAB) energy of photons emitted by fast moving ions can be corrected individually for the Doppler effect according to the particular observation angles of each detector segment. By a redundant fitting procedure the center of mass photon energy can be determined with high precision. This new Doppler-shift assisted spectroscopy is explained for the case study of 277.4 MeV/u Pb 82+ ions colliding with a N 2 -gas target at the heavy ion storage ring ESR. Spectroscopic information for hydrogenic Pb 81+ ions is given for the ground-state transitions, for the Balmer transitions, as well as for the total K-binding energy. (orig.)

Charged particle transport and extraction studies in the NSCL gas cell for stopping radioactive fragments

International Nuclear Information System (INIS)

Facina, M.; Bachelet, C.; Block, M.; Bollen, G.; Davies, D.; Folden, C.M.; Guenaut, C.; Huikari, J.; Kwan, E.; Morrissey, D.J.; Pang, G.K.; Prinke, A.; Ringle, R.; Savory, J.; Schury, P.; Schwarz, S.; Sumithrarachchi, C.; Sun, T.

2008-01-01

The NSCL gas-stopping station thermalizes high-energy projectile fragments for study in the low energy beam and ion trap (LEBIT) facility. The stopping and extraction of fast beams has been studied extensively and the extracted short-lived ions have been used in a series of mass measurements of exotic nuclei. Particle-in-cell simulations of ion drift in the gas cell have been performed. In the present paper calculation results are presented and compared to experimental data obtained with neutron-deficient and neutron-rich As and Se isotopes recently measured at LEBIT. Good agreement between the theoretical and experimental extraction efficiency was found.

Majority ion heating near the ion-ion hybrid layer in tokamaks

International Nuclear Information System (INIS)

Phillips, C.K.; Hosea, J.C.; Ignat, D.; Majeski, R.; Rogers, J.H.; Schilling, G.; Wilson, J.R.

1995-08-01

Efficient direct majority ion heating in a deuterium-tritium (D-T) reactor-grade plasma via absorption of fast magnetosonic waves in the ion cyclotron range of frequencies (ICRF) is discussed. Majority ion heating results from resonance overlap between the cyclotron layers and the D-T ion-ion hybrid layer in hot, dense plasmas for fast waves launched with high parallel wavenumbers. Analytic and numerical models are used to explore the regime in ITER plasmas

Synthesis and characterisation of nano structure lead (II) ion-imprinted polymer as a new sorbent for selective extraction and preconcentration of ultra trace amounts of lead ions from vegetables, rice, and fish samples.

Science.gov (United States)

Behbahani, Mohammad; Bagheri, Akbar; Taghizadeh, Mohsen; Salarian, Mani; Sadeghi, Omid; Adlnasab, Laleh; Jalali, Kobra

2013-06-01

This paper describes the preparation of new Pb(II)-imprinted polymeric particles using 2-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2'- azobisisobutyronitrile as the initiator, diphenylcarbazone as the ligand, acetonitril as the solvent, and Pb(NO(3))(2) as the template ion, through bulk polymerisation technique. The imprinted lead ions were removed from the polymeric matrix using 5 mL of HCl (2 mol.L(-1)) as the eluting solvent. The lead ion concentration was determined by flame atomic absorption spectrometry. Optimum pH for maximum sorption was obtained at 6.0. Sorption and desorption of Pb(II) ions on the IIP particles were quite fast and achieved fully over 5 min. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 75.4 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 245, 2.1%, and 0.42 ng mL(-1), respectively. The prepared ion-imprinted polymer particles have an increased selectivity toward Pb(II) ions over a range of competing metal ions with the same charge and similar ionic radius. This ion-imprinted polymer is an efficient solid phase for extraction and preconcentration of lead ions in complex matrixes. For proving that the proposed method is reliable, a wide range of food samples with different and complex matrixes was used. Copyright © 2012 Elsevier Ltd. All rights reserved.

Metal ion protection of DNA to fast neutron irradiation

International Nuclear Information System (INIS)

Constantinescu, B.; Bugoi, R.; Radulescu, I.; Radu, L.

1998-01-01

The most important effects of the ionising radiation are the single and double strand breaks (SSB and DBS), modifications of the DNA bases and deoxyribose, as well as the occurrence of alkali and heat labile sites (revealed as strand breaks after alkaline or thermic treatment of irradiated DNA). The ionising particles can have either direct effects on the DNA constituents or indirect effects, mediated by the OH - radicals, produced by water radiolysis. The occurrence of SSB and DSB in the chromatin DNA strands is supposed to hinder the DNA-dye complex formation. Usually, the dyes present different fluorescence parameters in the two possible states, so one can correlate the lifetime or the quantum yield with the extent of the damage. We took into account the protective effect offered both by histones, which behave as 'scavenger molecules' for OH - radicals and by the high compactness of DNA chromatin. Similar protective effects might be the results of the metallic ion addition which triggers some conformational transitions of the chromatin DNA towards a highly compacted structure. In this paper we present a study of the complexes of fast neutron irradiated chromatin with proflavine. Fluorimetric and time resolved spectroscopic determinations (single photon counting method) of chromatin-Pr complexes were realised. Information regarding the chromatin protein damage were obtained by monitoring the fluorescence of Trp. The chromatin was irradiated (20-100 Gy) with fast neutrons, obtained by the reaction of 13.5 MeV deuterons on a thick beryllium target at the IFIN-HH U-120 Cyclotron. The dose mean lineal energy in water at the point of interest was 50 keV/m and the mean dose rate was 1.5 Gy/min. By fluorescence determinations, changes of the Pr intercalation parameters in fast neutron irradiated chromatin DNA have been observed. Fluorescence techniques provide valuable information on the binding equilibrium by considering the radiation deexcitation of the complex. The

On velocity-space sensitivity of fast-ion D-alpha spectroscopy

DEFF Research Database (Denmark)

Salewski, Mirko; Geiger, B.; Moseev, Dmitry

2014-01-01

The velocity-space observation regions and sensitivities in fast-ion Dα (FIDA) spectroscopy measurements are often described by so-called weight functions. Here we derive expressions for FIDA weight functions accounting for the Doppler shift, Stark splitting, and the charge-exchange reaction...... and electron transition probabilities. Our approach yields an efficient way to calculate correctly scaled FIDA weight functions and implies simple analytic expressions for their boundaries that separate the triangular observable regions in (v‖, v⊥)-space from the unobservable regions. These boundaries...

Studies for determining thermal ion extraction potential for aluminium plasma generated by electron beam evaporator

Energy Technology Data Exchange (ETDEWEB)

Kumar, V Dileep; Barnwal, Tripti A; Mukherjee, Jaya; Gantayet, L M, E-mail: dileepv@barc.gov.i [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

2010-02-01

For effective evaporation of refractory metal, electron beam is found to be most suitable vapour generator source. Using electron beam, high throughput laser based purification processes are carried out. But due to highly concentrated electron beam, the vapour gets ionised and these ions lead to dilution of the pure product of laser based separation process. To estimate the concentration of these ions and extraction potential requirement to remove these ions from vapour stream, experiments have been conducted using aluminium as evaporant. The aluminium ingots were placed in water cooled copper crucible. Inserts were used to hold the evaporant, in order to attain higher number density in the vapour processing zone and also for confining the liquid metal. Parametric studies with beam power, number density and extraction potential were conducted. In this paper we discuss the trend of the generation of thermal ions and electrostatic field requirement for extraction.

Ions extraction and collection using the RF resonance method and taking into consideration the sputtering loss

International Nuclear Information System (INIS)

Xie Guofeng; Wang Dewu; Ying Chuntong

2005-01-01

One-dimensional ions extraction and collection using the RF resonance method is studied by PIC-MCC simulation. The energy and angle distribution of extracted ions is recorded and the sputtering loss is calculated. The results show that compared with parallel electrode method, RF resonance method has advantages such as shorter extraction time, lower collision loss and sputtering loss and higher collection ratio; the extraction time and collision loss are decreased with increasing extraction voltage, but the sputtering loss increases and collection ratio decreases; collision loss is decreased with increasing magnetic field, but the sputtering loss increases and collection ratio decreases. (authors)

Synergism of thiocyanate ions and microinterfacial surface as driving forces for heavy multi-metals extraction

Directory of Open Access Journals (Sweden)

Daniela Cadar

2018-05-01

Full Text Available A comprehensive study has been carried out to evaluate the extraction of heavy metals mixture (Co2+, Cr3+, Cu2+, Ni2+ from aqueous media by Winsor II non-ionic microemulsion, containing polyoxyethylene (4 lauryl ether as non-ionic surfactant and butyl acetate as organic phase. The extraction mechanism is based on the formation of thiocyanate complexes of metals and their transfer from aqueous to microemulsion phase, either towards the interfacial film of surfactant (Co2+ or into the core of micelles (Cr3+, Cu2+, Ni2+. The value of the distribution coefficient for Co2+ was higher than for the other studied metals and its extraction efficiency was not dependent on the working conditions, showing a maximum value (99.99% in all cases. By using successive extractions, chromium, nickel and copper ions that remained in the aqueous phase after first extraction were transported into the microemulsion phase, leading to an increase in the extraction efficiency up to 99.99% for chromium and copper, and 85% for nickel. Based on pH influence, a selective extraction of Co2+ and Cr3+ can be achieved, since the cobalt ions were completely extracted into the microemulsion phase at pH = 1, and the chromium ions still remained in the aqueous phase. Keywords: Nonionic microemulsion, Thiocyanate complexes of heavy metals, Simultaneous heavy metals extraction, Microinterfacial effect, Synergism

Collisionally induced stochastic dynamics of fast ions in solids

International Nuclear Information System (INIS)

Burgdoerfer, J.

1989-01-01

Recent developments in the theory of excited state formation in collisions of fast highly charged ions with solids are reviewed. We discuss a classical transport theory employing Monte-Carlo sampling of solutions of a microscopic Langevin equation. Dynamical screening by the dielectric medium as well as multiple collisions are incorporated through the drift and stochastic forces in the Langevin equation. The close relationship between the extrinsically stochastic dynamics described by the Langevin and the intrinsic stochasticity in chaotic nonlinear dynamical systems is stressed. Comparison with experimental data and possible modification by quantum corrections are discussed. 49 refs., 11 figs

Fast quantum logic gates with trapped-ion qubits

Science.gov (United States)

Schäfer, V. M.; Ballance, C. J.; Thirumalai, K.; Stephenson, L. J.; Ballance, T. G.; Steane, A. M.; Lucas, D. M.

2018-03-01

Quantum bits (qubits) based on individual trapped atomic ions are a promising technology for building a quantum computer. The elementary operations necessary to do so have been achieved with the required precision for some error-correction schemes. However, the essential two-qubit logic gate that is used to generate quantum entanglement has hitherto always been performed in an adiabatic regime (in which the gate is slow compared with the characteristic motional frequencies of the ions in the trap), resulting in logic speeds of the order of 10 kilohertz. There have been numerous proposals of methods for performing gates faster than this natural ‘speed limit’ of the trap. Here we implement one such method, which uses amplitude-shaped laser pulses to drive the motion of the ions along trajectories designed so that the gate operation is insensitive to the optical phase of the pulses. This enables fast (megahertz-rate) quantum logic that is robust to fluctuations in the optical phase, which would otherwise be an important source of experimental error. We demonstrate entanglement generation for gate times as short as 480 nanoseconds—less than a single oscillation period of an ion in the trap and eight orders of magnitude shorter than the memory coherence time measured in similar calcium-43 hyperfine qubits. The power of the method is most evident at intermediate timescales, at which it yields a gate error more than ten times lower than can be attained using conventional techniques; for example, we achieve a 1.6-microsecond-duration gate with a fidelity of 99.8 per cent. Faster and higher-fidelity gates are possible at the cost of greater laser intensity. The method requires only a single amplitude-shaped pulse and one pair of beams derived from a continuous-wave laser. It offers the prospect of combining the unrivalled coherence properties, operation fidelities and optical connectivity of trapped-ion qubits with the submicrosecond logic speeds that are usually

Investigation of the imaging properties of inorganic scintillation screens using high energetic ion beams

Energy Technology Data Exchange (ETDEWEB)

Lieberwirth, Alice [TU Darmstadt (Germany); JWG Universitaet Frankfurt/Main (Germany); Forck, Peter; Sieber, Thomas [GSI Darmstadt (Germany); Ensinger, Wolfgang; Lederer, Stephan [TU Darmstadt (Germany); Kester, Oliver [JWG Universitaet Frankfurt/Main (Germany)

2016-07-01

Inorganic scintillation screens are a common diagnostics tool in heavy ion accelerators. In order to investigate the imaging properties of various screen materials, four different material compositions were irradiated at GSI, using protons up to Uranium ions as projectiles. Beams were extracted from SIS18 with high energy (300 MeV/u) in slow and fast extraction mode. During irradiation the scintillation response of the screens was simultaneously recorded by two different optical setups to investigate light output, profile characteristics and emission spectra. It was observed, that fast extracted beams induce in general lower light output than slow extracted beams, while the light output per deposited energy decreases with atomic number. The analysis of the spectral emission as well as investigations with classical optical methods showed no significant defect-building in all materials, not even under irradiation with increasing beam intensity or over long time periods. The investigated scintillation screens can be considered as stable under irradiation with high energetic heavy ion pulses and are appropriate for beam diagnostics applications in future accelerator facilities like FAIR. Characteristic properties and application areas of the screens are presented in the poster.

A fast online hit verification method for the single ion hit system at GSI

International Nuclear Information System (INIS)

Du, G.; Fischer, B.; Barberet, P.; Heiss, M.

2006-01-01

For a single ion hit facility built to irradiate specific targets inside biological cells, it is necessary to prove that the ions hit the selected targets reliably because the ion hits usually cannot be seen. That ability is traditionally tested either indirectly by aiming at pre-etched tracks in a nuclear track detector or directly by making the ion tracks inside cells visible using a stain coupled to special proteins produced in response to ion hits. However, both methods are time consuming and hits can be verified only after the experiment. This means that targeting errors in the experiment cannot be corrected during the experiment. Therefore, we have developed a fast online hit verification method that measures the targeting accuracy electronically with a spatial resolution of ±1 μm before cell irradiation takes place. (authors)

Decontamination of Metal Ions in Soil by Supercritical CO2 Extraction with Crown Ether

Energy Technology Data Exchange (ETDEWEB)

Park, Jihe; Park, Kwangheon [Kyunghee University, Yongin (Korea, Republic of)

2015-05-15

Previous decontamination methods have shortcomings in that they produce additional waste due to the usage of solutions with chemical toxicity. Hence, demand is strong for new decontamination methods that can guarantee effective decontamination while decreasing the chemical solution. In particular, methods using supercritical CO2 as a means of decontamination are currently in progress. This study examines the method of decontaminating metallic ions inside soil using supercritical CO2. This paper examined the effects of extracting metallic ions inside soil using supercritical CO2 and crown ether as the ligand. It was confirmed that extraction effectiveness increases following greater usage of ligand and co-ligand, with a drastic increase in extraction effectiveness when using extracts over a certain dose. Moreover, it was shown that if the usage of ligand and additive decreases, the extraction ratio also decreases.

Decontamination of Metal Ions in Soil by Supercritical CO2 Extraction with Crown Ether

International Nuclear Information System (INIS)

Park, Jihe; Park, Kwangheon

2015-01-01

Previous decontamination methods have shortcomings in that they produce additional waste due to the usage of solutions with chemical toxicity. Hence, demand is strong for new decontamination methods that can guarantee effective decontamination while decreasing the chemical solution. In particular, methods using supercritical CO2 as a means of decontamination are currently in progress. This study examines the method of decontaminating metallic ions inside soil using supercritical CO2. This paper examined the effects of extracting metallic ions inside soil using supercritical CO2 and crown ether as the ligand. It was confirmed that extraction effectiveness increases following greater usage of ligand and co-ligand, with a drastic increase in extraction effectiveness when using extracts over a certain dose. Moreover, it was shown that if the usage of ligand and additive decreases, the extraction ratio also decreases

Towards a realistic 3D simulation of the extraction region in ITER NBI relevant ion source

Science.gov (United States)

Mochalskyy, S.; Wünderlich, D.; Fantz, U.; Franzen, P.; Minea, T.

2015-03-01

The development of negative ion (NI) sources for ITER is strongly accompanied by modelling activities. The ONIX code addresses the physics of formation and extraction of negative hydrogen ions at caesiated sources as well as the amount of co-extracted electrons. In order to be closer to the experimental conditions the code has been improved. It includes now the bias potential applied to first grid (plasma grid) of the extraction system, and the presence of Cs+ ions in the plasma. The simulation results show that such aspects play an important role for the formation of an ion-ion plasma in the boundary region by reducing the depth of the negative potential well in vicinity to the plasma grid that limits the extraction of the NIs produced at the Cs covered plasma grid surface. The influence of the initial temperature of the surface produced NI and its emission rate on the NI density in the bulk plasma that in turn affects the beam formation region was analysed. The formation of the plasma meniscus, the boundary between the plasma and the beam, was investigated for the extraction potentials of 5 and 10 kV. At the smaller extraction potential the meniscus moves closer to the plasma grid but as in the case of 10 kV the deepest meniscus bend point is still outside of the aperture. Finally, a plasma containing the same amount of NI and electrons (nH- =ne =1017 m-3) , representing good source conditioning, was simulated. It is shown that at such conditions the extracted NI current can reach values of ˜32 mA cm-2 using ITER-relevant extraction potential of 10 kV and ˜19 mA cm-2 at 5 kV. These results are in good agreement with experimental measurements performed at the small scale ITER prototype source at the test facility BATMAN.

Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics.

Science.gov (United States)

Yorita, T; Hatanaka, K; Fukuda, M; Ueda, H; Yasuda, Y; Morinobu, S; Tamii, A; Kamakura, K

2014-02-01

An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

Role of ethanol leaf extracts of Ficus glumosa on fasting blood ...

African Journals Online (AJOL)

Normal saline 5ml/kg, 100mg/kg, 200mg/kg and 400mg/kg of Ficus glumosa ethanol leaves extract respectively via ip while Group V received insulin 6 iu/kg. Fasting blood sugar levels were measured at one day intervals for 7 days. Rats were sacrifice for the Serum liver enzymes and liver tissue for th analysis on the 7 day.

Polyaspartate extraction of cadmium ions from contaminated soil: Evaluation and optimization using central composite design.

Science.gov (United States)

Mu'azu, Nuhu Dalhat; Haladu, Shamsuddeen A; Jarrah, Nabeel; Zubair, Mukarram; Essa, Mohammad H; Ali, Shaikh A

2018-01-15

The occurrences of heavy metal contaminated sites and soils and the need for devising environmentally friendly solutions have become global issues of serious concern. In this study, polyaspartate (a highly biodegradable agent) was synthesized using L-Aspartic acid via a new modified thermal procedure and employed for extraction of cadmium ions (Cd) from contaminated soil. Response surface methodology approach using 3 5 full faced centered central composite design was employed for modeling, evaluating and optimizing the influence of polyaspartate concentration (36-145mM), polyaspartate/soil ratio (5-25), initial heavy metal concentration (100-500mg/kg), initial pH (3-6) and extraction time (6-24h) on Cd ions extracted into the polyaspartate solution and its residual concentration in the treated soil. The Cd extraction efficacy obtained reached up to 98.8%. Increase in Cd extraction efficiency was associated with increase in the polyaspartate and Cd concentration coupled with lower polyaspertate/soil ratio and initial pH. Under the optimal conditions characterized with minimal utilization of the polyaspartate and high Cd ions removal, the extractible Cd in the polyaspartate solution reached up to 84.4mg/L which yielded 85% Cd extraction efficacy. This study demonstrates the suitability of using polyaspartate as an effective environmentally friendly chelating agent for Cd extraction from contaminated soils. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid-liquid extraction of U(VI), Np(V) et Th(IV) ions by two calix[4]arene carboxyls, and effect of Na+ and K+ alkaline ions

International Nuclear Information System (INIS)

Montavon, Gilles

1996-01-01

As the process mainly used for the reprocessing of nuclear wastes was the Purex process, this research thesis first presents this process and outlines that it allows the residual fissile matter to be recovered and reused for the fabrication of new fuel elements, but is neither efficient nor safe enough to separate fission and activation products. Thus, this thesis reports the study of extraction and selectivity properties of two compounds derived from the p-tert-butyl-calix[4]arene with respect to actinide ions such as Th(IV), U(VI) and Np(VI). The liquid-liquid extraction technique has been used with chloroform and 1,2-dichloroethane as solvents. After some generalities on actinides, calixarenes and the liquid-liquid extraction technique, and a presentation of the experimental method, the author reports and discusses the extractive properties of the studied calixarenes with respect to Na + and K + ions. Structural studies by proton NMR have been performed. He reports and discusses the liquid-liquid extraction on actinide ions when they are alone or in presence on Na + and K + alkaline ions [fr

Comparison of fast ion collective Thomson scattering measurements at ASDEX Upgrade with numerical simulations

DEFF Research Database (Denmark)

Salewski, Mirko; Meo, Fernando; Stejner Pedersen, Morten

2010-01-01

Collective Thomson scattering (CTS) experiments were carried out at ASDEX Upgrade to measure the one-dimensional velocity distribution functions of fast ion populations. These measurements are compared with simulations using the codes TRANSP/NUBEAM and ASCOT for two different neutral beam injecti...

The complex formation-partition and partition-association models of solvent extraction of ions

International Nuclear Information System (INIS)

Siekierski, S.

1976-01-01

Two models of the extraction process have been proposed. In the first model it is assumed that the partitioning neutral species is at first formed in the aqueous phase and then transferred into the organic phase. The second model is based on the assumption that equivalent amounts of cations are at first transferred from the aqueous into the organic phase and then associated to form a neutral molecule. The role of the solubility parameter in extraction and the relation between the solubility of liquid organic substances in water and the partition of complexes have been discussed. The extraction of simple complexes and complexes with organic ligands has been discussed using the first model. Partition coefficients have been calculated theoretically and compared with experimental values in some very simple cases. The extraction of ion pairs has been discussed using the partition-association model and the concept of single-ion partition coefficients. (author)

Fast quantum logic by selective displacement of hot trapped ions

International Nuclear Information System (INIS)

Sasura, Marek; Steane, Andrew M.

2003-01-01

The 'pushing gate' proposed by Cirac and Zoller for quantum logic in ion traps is discussed, in which a force is used to give a controlled push to a pair of trapped ions and thus realize a phase gate. The original proposal had a weakness in that it involved a hidden extreme sensitivity to the size of the force. Also, the physical origin of this force was not fully addressed. Here, we discuss the sensitivity and present a way to avoid it by choosing the spatial form of the pushing force in an optimal way. We also analyze the effect of imperfections in a pair of π pulses which are used to implement a 'spin echo' to cancel correlated errors. We present a physical model for the force, namely, the dipole force, and discuss the impact of unwanted photon scattering, and of finite temperature of the ions. The main effect of the temperature is to blur the phase of the gate owing to the ions exploring a range of values of the force. When the distance scale of the force profile is smaller than the ion separation, this effect is more important than the high-order terms in the Coulomb repulsion which were originally discussed. Overall, we find that whereas the pushing gate is not as resistant to imperfection as was supposed, it remains a significant candidate for ion trap quantum computing since it does not require ground-state cooling, and in some cases it does not require the Lamb-Dicke limit, while the gate rate is fast, close to (rather than small compared to) the trap vibrational frequency

Rate phenomena in uranium extraction by amines

International Nuclear Information System (INIS)

Coleman, C.F.; McDowell, W.J.

1979-01-01

Kinetics studies and other rate measurements are reviewed in the amine extraction of uranium and of some other related and associated metal ions. Equilibration is relatively fast in the uranium sulfate systems most important to uranium hydrometallurgy. Significantly slow equilibration has been encountered in some other systems. Most of the recorded rate information, both qualitative and quantitative, has come from exploratory and process-development work, while some kinetics studies have been directed specifically toward elucidation of extraction mechanisms. 71 references

Fast ion stabilization of the ion temperature gradient driven modes in the Joint European Torus hybrid-scenario plasmas: a trigger mechanism for internal transport barrier formation

Energy Technology Data Exchange (ETDEWEB)

Romanelli, M; Zocco, A [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); Crisanti, F, E-mail: Michele.Romanelli@ccfe.ac.u [Associazione Euratom-ENEA sulla Fusione, C.R. Frascati, Frascati (Italy)

2010-04-15

Understanding and modelling turbulent transport in thermonuclear fusion plasmas are crucial for designing and optimizing the operational scenarios of future fusion reactors. In this context, plasmas exhibiting state transitions, such as the formation of an internal transport barrier (ITB), are particularly interesting since they can shed light on transport physics and offer the opportunity to test different turbulence suppression models. In this paper, we focus on the modelling of ITB formation in the Joint European Torus (JET) [1] hybrid-scenario plasmas, where, due to the monotonic safety factor profile, magnetic shear stabilization cannot be invoked to explain the transition. The turbulence suppression mechanism investigated here relies on the increase in the plasma pressure gradient in the presence of a minority of energetic ions. Microstability analysis of the ion temperature gradient driven modes (ITG) in the presence of a fast-hydrogen minority shows that energetic ions accelerated by the ion cyclotron resonance heating (ICRH) system (hydrogen, n{sub H,fast}/n{sub D,thermal} up to 10%, T{sub H,fast}/T{sub D,thermal} up to 30) can increase the pressure gradient enough to stabilize the ITG modes driven by the gradient of the thermal ions (deuterium). Numerical analysis shows that, by increasing the temperature of the energetic ions, electrostatic ITG modes are gradually replaced by nearly electrostatic modes with tearing parity at progressively longer wavelengths. The growth rate of the microtearing modes is found to be lower than that of the ITG modes and comparable to the local E x B-velocity shearing rate. The above mechanism is proposed as a possible trigger for the formation of ITBs in this type of discharges.

Comparison of collective Thomson scattering signals due to fast ions in ITER scenarios with fusion and auxiliary heating

DEFF Research Database (Denmark)

Salewski, Mirko; Asunta, O.; Eriksson, L.-G.

2009-01-01

Auxiliary heating such as neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) will accelerate ions in ITER up to energies in the MeV range, i.e. energies which are also typical for alpha particles. Fast ions of any of these populations will elevate the collective Thomson...... functions of fast ions generated by NBI and ICRH are calculated for a steady-state ITER burning plasma equilibrium with the ASCOT and PION codes, respectively. The parameters for the auxiliary heating systems correspond to the design currently foreseen for ITER. The geometry of the CTS system for ITER...... is chosen such that near perpendicular and near parallel velocity components are resolved. In the investigated ICRH scenario, waves at 50MHz resonate with tritium at the second harmonic off-axis on the low field side. Effects of a minority heating scheme with He-3 are also considered. CTS scattering...

Edge Ion Heating by Launched High Harmonic Fast Waves in NSTX

International Nuclear Information System (INIS)

Biewer, T.M.; Bell, R.E.; Diem, S.J.; Phillips, C.K.; Wilson, J.R.; Ryan, P.M.

2004-01-01

A new spectroscopic diagnostic on the National Spherical Torus Experiment (NSTX) measures the velocity distribution of ions in the plasma edge simultaneously along both poloidal and toroidal views. An anisotropic ion temperature is measured during high-power high harmonic fast wave (HHFW) radio-frequency (rf) heating in helium plasmas, with the poloidal ion temperature roughly twice the toroidal ion temperature. Moreover, the measured spectral distribution suggests that two populations of ions are present and have temperatures of typically 500 eV and 50 eV with rotation velocities of -50 km/s and -10 km/s, respectively (predominantly perpendicular to the local magnetic field). This bi-modal distribution is observed in both the toroidal and poloidal views (for both He + and C 2+ ions), and is well correlated with the period of rf power application to the plasma. The temperature of the hot component is observed to increase with the applied rf power, which was scanned between 0 and 4.3 MW . The 30 MHz HHFW launched by the NSTX antenna is expected and observed to heat core electrons, but plasma ions do not resonate with the launched wave, which is typically at >10th harmonic of the ion cyclotron frequency in the region of observation. A likely ion heating mechanism is parametric decay of the launched HHFW into an Ion Bernstein Wave (IBW). The presence of the IBW in NSTX plasmas during HHFW application has been directly confirmed with probe measurements. IBW heating occurs in the perpendicular ion distribution, consistent with the toroidal and poloidal observations. Calculations of IBW propagation indicate that multiple waves could be created in the parametric decay process, and that most of the IBW power would be absorbed in the outer 10 to 20 cm of the plasma, predominantly on fully stripped ions. These predictions are in qualitative agreement with the observations, and must be accounted for when calculating the energy budget of the plasma

Development of ion imprinted polymers for the selective extraction of lanthanides from environmental samples

International Nuclear Information System (INIS)

Moussa, Manel

2016-01-01

The analysis of the lanthanide ions present at trace level in complex environmental matrices requires often a purification and preconcentration step. The solid phase extraction (SPE) is the most used sample preparation technique. To improve the selectivity of this step, Ion Imprinted Polymers (IIPs) can be used as SPE solid supports. The aim of this work was the development of IIPs for the selective extraction of lanthanide ions from environmental samples. In a first part, IIPs were prepared according to the trapping approach using 5,7-dichloroquinoline-8-ol as non-vinylated ligand. For the first time, the loss of the trapped ligand during template ion removal and sedimentation steps was demonstrated by HPLC-UV. Moreover, this loss was not repeatable, which led to a lack of repeatability of the SPE profiles. It was then demonstrated that the trapping approach is not appropriate for the IIPs synthesis. In a second part, IIPs were synthesized by chemical immobilization of methacrylic acid as vinylated monomer. The repeatability of the synthesis and the SPE protocol were confirmed. A good selectivity of the IIPs for all the lanthanide ions was obtained. IIPs were successfully used to selectively extract lanthanide ions from tap and river water. Finally, IIPs were synthesized by chemical immobilization of methacrylic acid and 4-vinylpyridine as functional monomers and either a light (Nd 3+ ) or a heavy (Er 3+ ) lanthanide ion as template. Both kinds of IIPs led to a similar selectivity for all lanthanide ions. Nevertheless, this selectivity can be modified by changing the nature and the pH of the washing solution used in the SPE protocol. (author)

A compact high resolution ion mobility spectrometer for fast trace gas analysis.

Science.gov (United States)

Kirk, Ansgar T; Allers, Maria; Cochems, Philipp; Langejuergen, Jens; Zimmermann, Stefan

2013-09-21

Drift tube ion mobility spectrometers (IMS) are widely used for fast trace gas detection in air, but portable compact systems are typically very limited in their resolving power. Decreasing the initial ion packet width improves the resolution, but is generally associated with a reduced signal-to-noise-ratio (SNR) due to the lower number of ions injected into the drift region. In this paper, we present a refined theory of IMS operation which employs a combined approach for the analysis of the ion drift and the subsequent amplification to predict both the resolution and the SNR of the measured ion current peak. This theoretical analysis shows that the SNR is not a function of the initial ion packet width, meaning that compact drift tube IMS with both very high resolution and extremely low limits of detection can be designed. Based on these implications, an optimized combination of a compact drift tube with a length of just 10 cm and a transimpedance amplifier has been constructed with a resolution of 183 measured for the positive reactant ion peak (RIP(+)), which is sufficient to e.g. separate the RIP(+) from the protonated acetone monomer, even though their drift times only differ by a factor of 1.007. Furthermore, the limits of detection (LODs) for acetone are 180 pptv within 1 s of averaging time and 580 pptv within only 100 ms.

4f and 5f trivalent ions complexation by diamides and uses in solvent extraction

International Nuclear Information System (INIS)

Huber, H.

1984-06-01

Extractive properties of N,N'-tetraalkylmalonamides were investigated in view to separate the actinides contained in highly radioactive wastes. N,N'-dimethyldioctylmalonamide (DMDOMA) was selected. It extracts trivalent actinide and lanthanide from concentrated nitric acid. Mineral acids extraction was studied, especially HNO 3 extraction. The distribution of HNO 3 can be interpreted by assuming that in the organic phase three main species are present: HNO 3 (DMDOMA) 2 , HNO 3 DMDOMA, (HNO 3 ) 2 DMDOMA. 5f and 4f trivalent ions are extracted according to the mechanism: M 3+ + 3NO 3 - + 4DMDOMA in equilibrium with [M(DMDOMA) 2 (NO 3 ) 3 ].(DMDOMA) 2 . The extraction of important ions like U(VI), Np(V), Pu(IV), Pu(VI), Zr(IV) and Fe(III) was investigated. The results showed that DMDOMA behave line the carbamoylmethylenephosphonates and could be an interesting alternative to these organophosphorus extractants [fr

A fast beam-ion instability

Energy Technology Data Exchange (ETDEWEB)

Stupakov, G V [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

1996-08-01

The ionization of residual gas by an electron beam in an accelerator generates ions that can resonantly couple to the beam through a wave propagating in the beam-ion system. Results of the study of a beam-ion instability are presented for a multi-bunch train taking into account the decoherence of ion oscillations due to the ion frequency spread and spatial variation of the ion frequency. It is shown that the combination of both effects can substantially reduce the growth rate of the instability. (author)

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

Science.gov (United States)

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

2017-12-01

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

Regulation of ion drifts and anisotropies by parametrically unstable finite-amplitude Alfvén-cyclotron waves in the fast solar wind

Energy Technology Data Exchange (ETDEWEB)

Maneva, Y. G. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Araneda, J. A. [Departamento de Física, Universidad de Concepción, 4070386 (Chile); Marsch, E., E-mail: yana.g.maneva@nasa.gov [Institute for Experimental and Applied Physics, Christian Albrechts University at Kiel, D-24118 Kiel (Germany)

2014-03-10

We study the preferential heating and differential acceleration of minor ions by dissipation of ion-acoustic waves (IAWs) generated by parametric instabilities of a finite-amplitude monochromatic Alfvén-cyclotron pump wave. We consider the associated kinetic effects of Landau damping and nonlinear pitch-angle scattering of protons and α particles in the tenuous plasma of coronal holes and the fast solar wind. Various data collected by Wind spacecraft show signatures for a local transverse heating of the minor ions, presumably by Alfvén-cyclotron wave dissipation, and an unexpected parallel heating by a so far unknown mechanism. Here, we present the results from a set of 1.5 dimensional hybrid simulations in search for a plausible explanation for the observed field-aligned kinetic features in the fast solar wind minor ions. We investigate the origin and regulation of ion relative drifts and temperature anisotropies in low plasma β, fast solar wind conditions. Depending on their initial drifts, both ion species can heat up not only transversely through cyclotron resonance and non-resonant wave-particle interactions, but also strongly in the parallel direction by Landau damping of the daughter IAWs. We discuss the dependence of the relative ion drifts and temperature anisotropies on the plasma β of the individual species and we describe the effect of the pump wave amplitude on the ion heating and acceleration.

Extraction of metals from liquid effluent using modified inorganic ion exchangers

International Nuclear Information System (INIS)

Hudson, M.J.

1993-01-01

Inorganic ion exchangers such as goethite, titanium (IV) oxide; silica and zeolites have been modified to examine the extraction of ruthenium; technetium and cobalt from liquid effluent. In addition, tin (IV) hydrogenphosphate and antimony hydrogenphosphate have been also examined in the modified and unmodified forms. It has been shown that some of the above reagents are able to remove the required metal ions from aqueous solution at the trace and mg L -1 levels. (author)

ITER Fast Ion Collective Thomson Scattering

DEFF Research Database (Denmark)

Bindslev, Henrik; Meo, Fernando; Korsholm, Søren Bang

In this report we investigate the feasibility of diagnosing the fast ions in ITER by collective Thomson scattering (CTS), exploring and comparing the diagnostic potentials of CTS systems base on a range of different probe frequencies. In the first section we first recall the requirements for meas...... the diagnostic potentials uncovered in the preceding four sections. A number of more detailed discussions are placed in appendices along with supporting material....... for measurements of the confined fusion alpha particles in ITER set by the ITER team. Then we outline the considerations, which enter into the selection and evaluation of CTS systems. System definition includes choice of probe frequency, geometry of probe and receiver beam patterns and probe power, but ultimately...... covers many more details. Here we introduce terms and methods used in the more detailed system evaluations later in the report. In Sections 2 through 5 we consider four different types of CTS systems, which differ by the ranges in which their probe frequencies lie. In Section 6 we summarize and compare...

Exit points, on plasma, of lost fast ions during NBI in TJ-II

International Nuclear Information System (INIS)

Guasp, J.

1995-09-01

The distribution of the exit points, on plasma border, for the lost fast ions during tangential balanced NBI in TJ-II helical axis Stellarator is theoretically analysed, as well for direct as for delayed losses. The link between the position of those exit points and the corresponding at birth, orbits and drifts is analysed also, it is shown that such relation is rather independent of beam energy and plasma density and is mainly related to the magnetic configuration characteristics. This study is a needed intermediate step to the analysis of impacts of those ions on the vacuum vessel of TJ-II

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

International Nuclear Information System (INIS)

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

2009-01-01

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

Ion-pair extraction of [3H]stobadine from biological fluids

International Nuclear Information System (INIS)

Scasnar, V.

1998-01-01

A simple and specific radiometric assay was developed for the determination of stobadine, a cardioprotective drug, in the serum of experimental animals. The assay is based on a single extraction step of the radioactively labeled drug from serum into the benzene solution of dicarbolide of cobalt followed by quantitation of the extracted radioactivity by using liquid scintillation counting. The extraction mechanism involves the ion-pair formation between the protonized molecule of stobadine and the hydrophobic, negatively charged molecule of dicarbolide of cobalt. The extraction yield of stobadine from 1 ml of serum was 95% in the concentration range from 1 to 6000 ng/ml. The co-extraction of metabolites was less than 5%. The method was applied to the determination of stobadine in serum of dogs and the data obtained were in a good agreement with those obtained by high performance liquid chromatography. (author)

Time dependent solutions of the Fokker-Planck equation for fast fusion ions

International Nuclear Information System (INIS)

Gnavi, G.; Gratton, F.T.; Heyn, M.

1990-01-01

Approximate time dependent solutions for the Fokker-Planck equation for fast fusion ions from an isotropic, monoenergetic source are presented, for the problem of D - T - He 3 reactions. The equations include the effect of diffusion, which is particularly noticeable in the distribution of particles of lower energy and in the formation of a tail of particles with energy higher than that of the source. (Author)

Experimental demonstration of ion extraction from magnetic thrust chamber for laser fusion rocket

Science.gov (United States)

Saito, Naoya; Yamamoto, Naoji; Morita, Taichi; Edamoto, Masafumi; Nakashima, Hideki; Fujioka, Shinsuke; Yogo, Akifumi; Nishimura, Hiroaki; Sunahara, Atsushi; Mori, Yoshitaka; Johzaki, Tomoyuki

2018-05-01

A magnetic thrust chamber is an important system of a laser fusion rocket, in which the plasma kinetic energy is converted into vehicle thrust by a magnetic field. To investigate the plasma extraction from the system, the ions in a plasma are diagnosed outside the system by charge collectors. The results clearly show that the ion extraction does not strongly depend on the magnetic field strength when the energy ratio of magnetic field to plasma is greater than 4.3, and the magnetic field pushes back the plasma to generate a thrust, as previously suggested by numerical simulation and experiments.

Role of ethanol leaf extracts of Ficus Glumosa on fasting blood ...

African Journals Online (AJOL)

Normal saline 5ml/kg, 100mg/kg, 200mg/kg and 400mg/kg of Ficus glumosa ethanol leaves extract respectively via ip while Group V received insulin 6 iu/kg. Fasting blood sugar levels were measured at one day intervals for 7 days. Rats were sacrifice for the Serum liver enzymes and liver the tissue for analysis on the 7 day ...

Optimized Extraction of H– by Three-Electrode Faraday Cup System in Magnetized Sheet Plasma Ion Source

Directory of Open Access Journals (Sweden)

M. S. Fernandez

2003-06-01

Full Text Available A locally designed rectangular parallelepiped, three-electrode Faraday cup system has been developed.Its design incorporates the capability of simultaneous extraction and deposition of the H– ions on substrates.The device functions to attain prescribed selectivity conditions of extracted ions, with controlled energies,for deposition or adsorption. It has been proven to detect the ions at filter bias voltage of 13.61 V with acurrent density of 5.3 A/m2 that is relatively higher than reported (Abate & Ramos, 2000.

Spectroscopic measurements of anode plasma with cryogenic pulsed ion sources

International Nuclear Information System (INIS)

Yoneda, H.; Urata, T.; Ohbayashi, K.; Kim, Y.; Horioka, K.; Kasuya, K.

1987-01-01

In ion beam diodes, electromagnetic wave is coupled to ion beam. Ion is extracted from anode plasma, which is produced early in the power pulse. However, exact mechanism of anode plasma production, expansion and ion extraction process is unknown. In particularly, anode plasma expansion is seemed to be one of the reasons of rapid impedance collapse of the diode, which is serious problem in high power experiments. Some experimental results showed that anode plasma expansion velocity was about 5 times larger than that inferred from simple thermal velocity. Several explanations for these results were proposed; for example, electron collisionarity in anode plasma, fast neutral gas particle, diamagnetism. To solve this question, it is necessary to measure the characteristic of anode plasma with space and time resolution. The authors made spectroscopic measurements to investigate variety of electron temperature, electron density, expansion velocity of anode plasma with various ion sources

Development of the scintillator-based probe for fast-ion losses in the HL-2A tokamak

Science.gov (United States)

Zhang, Y. P.; Liu, Yi; Luo, X. B.; Isobe, M.; Yuan, G. L.; Liu, Y. Q.; Hua, Y.; Song, X. Y.; Yang, J. W.; Li, X.; Chen, W.; Li, Y.; Yan, L. W.; Song, X. M.; Yang, Q. W.; Duan, X. R.

2014-05-01

A new scintillator-based lost fast-ion probe (SLIP) has been developed and operated in the HL-2A tokamak [L. W. Yan, X. R. Duan, X. T. Ding, J. Q. Dong, Q. W. Yang, Yi Liu, X. L. Zou, D. Q. Liu, W. M. Xuan, L. Y. Chen, J. Rao, X. M. Song, Y. Huang, W. C. Mao, Q. M. Wang, Q. Li, Z. Cao, B. Li, J. Y. Cao, G. J. Lei, J. H. Zhang, X. D. Li, W. Chen, J. Chen, C. H. Cui, Z. Y. Cui, Z. C. Deng, Y. B. Dong, B. B. Feng, Q. D. Gao, X. Y. Han, W. Y. Hong, M. Huang, X. Q. Ji, Z. H. Kang, D. F. Kong, T. Lan, G. S. Li, H. J. Li, Qing Li, W. Li, Y. G. Li, A. D. Liu, Z. T. Liu, C. W. Luo, X. H. Mao, Y. D. Pan, J. F. Peng, Z. B. Shi, S. D. Song, X. Y. Song, H. J. Sun, A. K. Wang, M. X. Wang, Y. Q. Wang, W. W. Xiao, Y. F. Xie, L. H. Yao, D. L. Yu, B. S. Yuan, K. J. Zhao, G. W. Zhong, J. Zhou, J. C. Yan, C. X. Yu, C. H. Pan, Y. Liu, and the HL-2A Team, Nucl. Fusion 51, 094016 (2011)] to measure the losses of neutral beam ions. The design of the probe is based on the concept of the α-particle detectors on Tokamak Fusion Test Reactor (TFTR) using scintillator plates. The probe is capable of traveling across an equatorial plane port and sweeping the aperture angle rotationally with respect to the axis of the probe shaft by two step motors, in order to optimize the radial position and the collimator angle. The energy and the pitch angle of the lost fast ions can be simultaneously measured if the two-dimensional image of scintillation light intensity due to the impact of the lost fast ions is detected. Measurements of the fast-ion losses using the probe have been performed during HL-2A neutral beam injection discharges. The clear experimental evidence of enhanced losses of beam ions during disruptions has been obtained by means of the SLIP system. A detailed description of the probe system and the first experimental results are reported.

Development of the scintillator-based probe for fast-ion losses in the HL-2A tokamak

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y. P., E-mail: zhangyp@swip.ac.cn; Liu, Yi; Yuan, G. L.; Song, X. Y.; Yang, J. W.; Li, X.; Chen, W.; Li, Y.; Yan, L. W.; Song, X. M.; Yang, Q. W.; Duan, X. R. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Luo, X. B.; Liu, Y. Q.; Hua, Y. [Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610041 (China); Isobe, M. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5259 (Japan)

2014-05-15

A new scintillator-based lost fast-ion probe (SLIP) has been developed and operated in the HL-2A tokamak [L. W. Yan, X. R. Duan, X. T. Ding, J. Q. Dong, Q. W. Yang, Yi Liu, X. L. Zou, D. Q. Liu, W. M. Xuan, L. Y. Chen, J. Rao, X. M. Song, Y. Huang, W. C. Mao, Q. M. Wang, Q. Li, Z. Cao, B. Li, J. Y. Cao, G. J. Lei, J. H. Zhang, X. D. Li, W. Chen, J. Chen, C. H. Cui, Z. Y. Cui, Z. C. Deng, Y. B. Dong, B. B. Feng, Q. D. Gao, X. Y. Han, W. Y. Hong, M. Huang, X. Q. Ji, Z. H. Kang, D. F. Kong, T. Lan, G. S. Li, H. J. Li, Qing Li, W. Li, Y. G. Li, A. D. Liu, Z. T. Liu, C. W. Luo, X. H. Mao, Y. D. Pan, J. F. Peng, Z. B. Shi, S. D. Song, X. Y. Song, H. J. Sun, A. K. Wang, M. X. Wang, Y. Q. Wang, W. W. Xiao, Y. F. Xie, L. H. Yao, D. L. Yu, B. S. Yuan, K. J. Zhao, G. W. Zhong, J. Zhou, J. C. Yan, C. X. Yu, C. H. Pan, Y. Liu, and the HL-2A Team , Nucl. Fusion 51, 094016 (2011)] to measure the losses of neutral beam ions. The design of the probe is based on the concept of the α-particle detectors on Tokamak Fusion Test Reactor (TFTR) using scintillator plates. The probe is capable of traveling across an equatorial plane port and sweeping the aperture angle rotationally with respect to the axis of the probe shaft by two step motors, in order to optimize the radial position and the collimator angle. The energy and the pitch angle of the lost fast ions can be simultaneously measured if the two-dimensional image of scintillation light intensity due to the impact of the lost fast ions is detected. Measurements of the fast-ion losses using the probe have been performed during HL-2A neutral beam injection discharges. The clear experimental evidence of enhanced losses of beam ions during disruptions has been obtained by means of the SLIP system. A detailed description of the probe system and the first experimental results are reported.

Development of the scintillator-based probe for fast-ion losses in the HL-2A tokamak

International Nuclear Information System (INIS)

Zhang, Y. P.; Liu, Yi; Yuan, G. L.; Song, X. Y.; Yang, J. W.; Li, X.; Chen, W.; Li, Y.; Yan, L. W.; Song, X. M.; Yang, Q. W.; Duan, X. R.; Luo, X. B.; Liu, Y. Q.; Hua, Y.; Isobe, M.

2014-01-01

A new scintillator-based lost fast-ion probe (SLIP) has been developed and operated in the HL-2A tokamak [L. W. Yan, X. R. Duan, X. T. Ding, J. Q. Dong, Q. W. Yang, Yi Liu, X. L. Zou, D. Q. Liu, W. M. Xuan, L. Y. Chen, J. Rao, X. M. Song, Y. Huang, W. C. Mao, Q. M. Wang, Q. Li, Z. Cao, B. Li, J. Y. Cao, G. J. Lei, J. H. Zhang, X. D. Li, W. Chen, J. Chen, C. H. Cui, Z. Y. Cui, Z. C. Deng, Y. B. Dong, B. B. Feng, Q. D. Gao, X. Y. Han, W. Y. Hong, M. Huang, X. Q. Ji, Z. H. Kang, D. F. Kong, T. Lan, G. S. Li, H. J. Li, Qing Li, W. Li, Y. G. Li, A. D. Liu, Z. T. Liu, C. W. Luo, X. H. Mao, Y. D. Pan, J. F. Peng, Z. B. Shi, S. D. Song, X. Y. Song, H. J. Sun, A. K. Wang, M. X. Wang, Y. Q. Wang, W. W. Xiao, Y. F. Xie, L. H. Yao, D. L. Yu, B. S. Yuan, K. J. Zhao, G. W. Zhong, J. Zhou, J. C. Yan, C. X. Yu, C. H. Pan, Y. Liu, and the HL-2A Team , Nucl. Fusion 51, 094016 (2011)] to measure the losses of neutral beam ions. The design of the probe is based on the concept of the α-particle detectors on Tokamak Fusion Test Reactor (TFTR) using scintillator plates. The probe is capable of traveling across an equatorial plane port and sweeping the aperture angle rotationally with respect to the axis of the probe shaft by two step motors, in order to optimize the radial position and the collimator angle. The energy and the pitch angle of the lost fast ions can be simultaneously measured if the two-dimensional image of scintillation light intensity due to the impact of the lost fast ions is detected. Measurements of the fast-ion losses using the probe have been performed during HL-2A neutral beam injection discharges. The clear experimental evidence of enhanced losses of beam ions during disruptions has been obtained by means of the SLIP system. A detailed description of the probe system and the first experimental results are reported

Spatial distribution of {gamma} emissivity and fast ions during ({sup 3}He)D ICRF heating experiments on JET

Energy Technology Data Exchange (ETDEWEB)

Start, D F.H. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Righi, E [Imperial Coll. of Science and Technology, London (United Kingdom); Warrick, C [UKAEA Culham Lab., Abingdon (United Kingdom)

1994-07-01

A model is presented that can simulate the {gamma} emissivity in the poloidal cross-section during ({sup 3}He)D ICRF heated discharges in JET plasmas, by merging information obtained from the fast ion distribution and from nuclear reactions producing the observed {gamma} emissivity (production of {gamma} photons during {sup 3}He-{sup 9}Be reactions). This technique can play an important role in the identification of plasma instabilities that affect the redistribution of the fast ions in the plasma, like the TAE modes and the ripple in the tokamak magnetic field. 9 refs., 4 figs., 1 tab.

Monte-Carlo Orbit/Full Wave Simulation of Fast Alfvén Wave (FW) Damping on Resonant Ions in Tokamaks

Science.gov (United States)

Choi, M.; Chan, V. S.; Tang, V.; Bonoli, P.; Pinsker, R. I.; Wright, J.

2005-09-01

To simulate the resonant interaction of fast Alfvén wave (FW) heating and Coulomb collisions on energetic ions, including finite orbit effects, a Monte-Carlo code ORBIT-RF has been coupled with a 2D full wave code TORIC4. ORBIT-RF solves Hamiltonian guiding center drift equations to follow trajectories of test ions in 2D axisymmetric numerical magnetic equilibrium under Coulomb collisions and ion cyclotron radio frequency quasi-linear heating. Monte-Carlo operators for pitch-angle scattering and drag calculate the changes of test ions in velocity and pitch angle due to Coulomb collisions. A rf-induced random walk model describing fast ion stochastic interaction with FW reproduces quasi-linear diffusion in velocity space. FW fields and its wave numbers from TORIC are passed on to ORBIT-RF to calculate perpendicular rf kicks of resonant ions valid for arbitrary cyclotron harmonics. ORBIT-RF coupled with TORIC using a single dominant toroidal and poloidal wave number has demonstrated consistency of simulations with recent DIII-D FW experimental results for interaction between injected neutral-beam ions and FW, including measured neutron enhancement and enhanced high energy tail. Comparison with C-Mod fundamental heating discharges also yielded reasonable agreement.

Metabolic profiles and bile acid extraction rate in the liver of cows with fasting-induced hepatic lipidosis.

Science.gov (United States)

Mohamed, T; Oikawa, S; Iwasaki, Y; Mizunuma, Y; Takehana, K; Endoh, D; Kurosawa, T; Sato, H

2004-04-01

This study was designed to monitor lipid profile in the portal and hepatic blood of cows with fasting-induced hepatic lipidosis, and to compare the results with those in the jugular blood. The work was also carried out to investigate bile acid (BA) in these vessels, and further to investigate BA extraction rate in the liver. Five cows were equipped with catheters in the portal, hepatic and jugular veins (day 0), fasted for 4 days (day 1-day 4) and then refed (day 5-day 11). Before morning feeding, blood was sampled before, during and after fasting from the catheterized vessels. In the portal blood, the concentration of non-esterified fatty acids (NEFA) showed a progressive increase and at day 5 there was an approximate twofold rise. Increased NEFA concentrations were also found similarly in the other two veins. At day 5, beta-hydroxybutyrate (BHBA) in the portal, hepatic and jugular blood rose to 197, 190 and 186% of the pre-fasting value, respectively. However, the concentrations of NEFA and BHBA in the three veins gradually returned to pre-fasting concentration during the refeeding period. Compared with the pre-fasting value at day 0, the content of liver triglyceride (TG) increased significantly at day 5 (P hepatic extraction rate of BA dropped from 3.1 times pre-fasting to 2.2 times during fasting. There were no significant differences in the concentrations of glucose, TG, total cholesterol, cholesterol esters, free cholesterol and phospholipids. The results of the current study show that metabolic alterations occur in the portal, hepatic and jugular veins during induction of hepatic lipidosis in cows, and mostly metabolites, with exception of BA concentration, run parallel. The decreased BA extraction rate in the liver of fasted cows was considered to reflect hepatic cell impairment caused by TG accumulation. Hopefully, the findings, at least in part, contribute to the explanation of the pathophysiology of hepatic lipidosis in dairy cows.

Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

Science.gov (United States)

Toivanen, V; Bellodi, G; Dimov, V; Küchler, D; Lombardi, A M; Maintrot, M

2016-02-01

Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

Investigation of Ion Absorption of the High Harmonic Fast Wave in NSTX using HPRT

International Nuclear Information System (INIS)

Rosenberg, A.; Menard, J.E.; LeBlanc, B.P.

2001-01-01

Understanding high harmonic fast wave (HHFW) power absorption by ions in a spherical torus (ST) is of critical importance to assessing the wave's viability as a means of heating and especially driving current. In this work, the HPRT code is used to calculate absorption for helium and deuterium, with and without minority hydrogen in National Spherical Torus Experiment (NSTX) plasmas using experimental EFIT code equilibria and kinetic profiles. HPRT is a two-dimensional ray-tracing code which uses the full hot plasma dielectric to compute the perpendicular wave number along the hot electron and cold ion plasma ray path. Ion and electron absorption dependence on antenna phasing, ion temperature, beta (subscript t), and minority temperature and concentration is analyzed. These results form the basis for comparisons with other codes, such as CURRAY, METS, TORIC, and AORSA

Fast ion-atom and ion-molecule collisions

CERN Document Server

2013-01-01

The principal goal of this book is to provide state-of-the art coverage of the non-relativistic three- and four-body theories at intermediate and high energy ion-atom and ion-molecule collisions. The focus is on the most frequently studied processes: electron capture, ionization, transfer excitation and transfer ionization. The content is suitable both for graduate students and experienced researchers. For these collisions, the literature has seen enormous renewal of activity in the development and applications of quantum-mechanical theories. This subject is of relevance in several branches of science and technology, like accelerator-based physics, the search for new sources of energy and high temperature fusion of light ions. Other important applications are in life sciences via medicine, where high-energy ion beams are used in radiotherapy for which a number of storage ring accelerators are in full operation, under construction or planned to be built worldwide. Therefore, it is necessary to review this fiel...

Fast-ion transport induced by Alfvén eigenmodes in the ASDEX Upgrade tokamak

DEFF Research Database (Denmark)

Garcia-Munoz, M.; Classen, I.G.J.; Geiger, B.

2011-01-01

A comprehensive suite of diagnostics has allowed detailed measurements of the Alfvén eigenmode (AE) spatial structure and subsequent fast-ion transport in the ASDEX Upgrade (AUG) tokamak [1]. Reversed shear Alfvén eigenmodes (RSAEs) and toroidal induced Alfvén eigenmodes (TAEs) have been driven u...

Bayesian Integrated Data Analysis of Fast-Ion Measurements by Velocity-Space Tomography

DEFF Research Database (Denmark)

Salewski, M.; Nocente, M.; Jacobsen, A.S.

2018-01-01

Bayesian integrated data analysis combines measurements from different diagnostics to jointly measure plasma parameters of interest such as temperatures, densities, and drift velocities. Integrated data analysis of fast-ion measurements has long been hampered by the complexity of the strongly non...... framework. The implementation for different types of diagnostics as well as the uncertainties are discussed, and we highlight the importance of integrated data analysis of all available detectors....

Solvent extraction of europium(III) with benzoylacetone and benzoyltrifluoroacetone into carbon tetrachloride in the absence and presence of tetrabutylammonium ions

International Nuclear Information System (INIS)

Noro, Junji; Sekine, Tatsuya.

1992-01-01

The solvent extraction of europium (III) in 0.1 mol dm -3 sodium nitrate solutions with benzoylacetone (Hbza) or benzoyltrifluoroacetone (Hbfa) in carbon tetrachloride was measured in the absence and presence or tetrabutylammonium ions (tba + ). Although extraction with Hbfa occurred at lower pH than with Hbza, the extraction measured as a function of the β-diketonate ion concentration in the aqueous phase was rather similar. It was also found that extraction with Hbfa was greatly enhanced by the addition of tba + , the effect, however, was negligible with Hbza. The data were analyzed from the stand point that the neutral metal chelate, Eu(bfa) 3 , was extracted into the organic phase and associated with ion-pairs of the reagents, bfa - tba + , in this phase. It was also found that though extraction of ion-pairs of bfa - tba + occurred, that of bza - tba + was negligible. Thus, the reason for the negligible extraction of the ternary complex, Eu (bza) 4 - tba + , was explained in terms of the negligible extraction of the bza - tba + , which might associate with Eu(bza) 3 in the organic phase. (author)

Numerical modeling of the Linac4 negative ion source extraction region by 3D PIC-MCC code ONIX

CERN Document Server

Mochalskyy, S; Minea, T; Lifschitz, AF; Schmitzer, C; Midttun, O; Steyaert, D

2013-01-01

At CERN, a high performance negative ion (NI) source is required for the 160 MeV H- linear accelerator Linac4. The source is planned to produce 80 mA of H- with an emittance of 0.25 mm mradN-RMS which is technically and scientifically very challenging. The optimization of the NI source requires a deep understanding of the underling physics concerning the production and extraction of the negative ions. The extraction mechanism from the negative ion source is complex involving a magnetic filter in order to cool down electrons’ temperature. The ONIX (Orsay Negative Ion eXtraction) code is used to address this problem. The ONIX is a selfconsistent 3D electrostatic code using Particles-in-Cell Monte Carlo Collisions (PIC-MCC) approach. It was written to handle the complex boundary conditions between plasma, source walls, and beam formation at the extraction hole. Both, the positive extraction potential (25kV) and the magnetic field map are taken from the experimental set-up, in construction at CERN. This contrib...

Simulations of toroidal Alfvén eigenmode excited by fast ions on the Experimental Advanced Superconducting Tokamak

Science.gov (United States)

Pei, Youbin; Xiang, Nong; Shen, Wei; Hu, Youjun; Todo, Y.; Zhou, Deng; Huang, Juan

2018-05-01

Kinetic-MagnetoHydroDynamic (MHD) hybrid simulations are carried out to study fast ion driven toroidal Alfvén eigenmodes (TAEs) on the Experimental Advanced Superconducting Tokamak (EAST). The first part of this article presents the linear benchmark between two kinetic-MHD codes, namely MEGA and M3D-K, based on a realistic EAST equilibrium. Parameter scans show that the frequency and the growth rate of the TAE given by the two codes agree with each other. The second part of this article discusses the resonance interaction between the TAE and fast ions simulated by the MEGA code. The results show that the TAE exchanges energy with the co-current passing particles with the parallel velocity |v∥ | ≈VA 0/3 or |v∥ | ≈VA 0/5 , where VA 0 is the Alfvén speed on the magnetic axis. The TAE destabilized by the counter-current passing ions is also analyzed and found to have a much smaller growth rate than the co-current ions driven TAE. One of the reasons for this is found to be that the overlapping region of the TAE spatial location and the counter-current ion orbits is narrow, and thus the wave-particle energy exchange is not efficient.

Exit points, on plasma, of lost fast ions during NBI in TJ-II

International Nuclear Information System (INIS)

Guasp, J.

1995-01-01

The distribution of the exit points, on plasma border, for the lost fast ions during tangential balanced NBI in TJ-II helical axis Stellarator is theoretically analysed, as well for direct as for delayed losses. The link between, the position of those exit points and the corresponding at birth, orbits and drifts is analysed also. It is shown that such relation is rather independent of beam energy and plasma density and is mainly related to the magnetic configuration characteristics. This study is a needed intermediate step to the analysis of impacts of those ions on the vacuum vessel of TJ-II. (Author) 2 refs

Charge steering of laser plasma accelerated fast ions in a liquid spray — creation of MeV negative ion and neutral atom beams

International Nuclear Information System (INIS)

Schnürer, M.; Abicht, F.; Priebe, G.; Braenzel, J.; Prasad, R.; Borghesi, M.; Andreev, A.; Nickles, P. V.; Jequier, S.; Tikhonchuk, V.; Ter-Avetisyan, S.

2013-01-01

The scenario of “electron capture and loss” has been recently proposed for the formation of negative ion and neutral atom beams with up to MeV kinetic energy [S. Ter-Avetisyan, et al., Appl. Phys. Lett. 99, 051501 (2011)]. Validation of these processes and of their generic nature is here provided in experiments where the ion source and the interaction medium have been spatially separated. Fast positive ions accelerated from a laser plasma source are sent through a cold spray where their charge is changed. Such formed neutral atom or negative ion has nearly the same momentum as the original positive ion. Experiments are released for protons, carbon, and oxygen ions and corresponding beams of negative ions and neutral atoms have been obtained. The electron capture and loss phenomenon is confirmed to be the origin of the negative ion and neutral atom beams. The equilibrium ratios of different charge components and cross sections have been measured. Our method is general and allows the creation of beams of neutral atoms and negative ions for different species which inherit the characteristics of the positive ion source

Randomized quasi-Monte Carlo simulation of fast-ion thermalization

Science.gov (United States)

Höök, L. J.; Johnson, T.; Hellsten, T.

2012-01-01

This work investigates the applicability of the randomized quasi-Monte Carlo method for simulation of fast-ion thermalization processes in fusion plasmas, e.g. for simulation of neutral beam injection and radio frequency heating. In contrast to the standard Monte Carlo method, the quasi-Monte Carlo method uses deterministic numbers instead of pseudo-random numbers and has a statistical weak convergence close to {O}(N^{-1}) , where N is the number of markers. We have compared different quasi-Monte Carlo methods for a neutral beam injection scenario, which is solved by many realizations of the associated stochastic differential equation, discretized with the Euler-Maruyama scheme. The statistical convergence of the methods is measured for time steps up to 214.

Influence of resonant magnetic perturbations on transient heat load deposition and fast ion losses

International Nuclear Information System (INIS)

Rack, Michael Thomas

2014-01-01

Thermonuclear fusion is the energy conversion process which keeps the sun shining. For the last six decades, researchers have been investigating the physics involved in order to enable the usage of this energy supply on Earth. The most promising candidates for fusion power plants are based on magnetic confinement of plasma to provide the ideal conditions for efficient thermonuclear fusion in well controlled surroundings. One important aspect is the control of instabilities that occur in the edge region of the plasma and lead to an ejection of huge amounts of energy. Magnetic perturbation fields which are resonant in the plasma edge are found to modify the plasma favourably and reduce the impact of these instabilities. This dissertation focuses on the effects of resonant magnetic perturbation fields on the ejected energy as well as on the drawbacks of these perturbation fields. The transient energy ejection which is triggered by the instabilities causes extreme heat loads on the wall components in fusion devices. Therefore, it is crucial to understand how resonant magnetic perturbation fields affect the heat load deposition. Furthermore, the impact of resonant magnetic perturbation fields on the confinement of fast ions is an important aspect as fast ions are still required to be well confined in order to avoid additional wall loads and increase the fusion efficiency. Recent upgrades on the Joint European Torus allow for a detailed study of the heat load deposition profiles caused by transient events. Throughout this work, the new features are used for the study of the modifications of the transient heat load depositions that occur if resonant magnetic perturbation fields are applied. This leads to a further understanding of the processes involved during the plasma edge instabilities. Additionally, an alternative method using lower hybrid waves for applying resonant magnetic perturbations is investigated. Furthermore, a new diagnostic, capable of detecting fast ion

Influence of resonant magnetic perturbations on transient heat load deposition and fast ion losses

Energy Technology Data Exchange (ETDEWEB)

Rack, Michael Thomas

2014-07-11

Thermonuclear fusion is the energy conversion process which keeps the sun shining. For the last six decades, researchers have been investigating the physics involved in order to enable the usage of this energy supply on Earth. The most promising candidates for fusion power plants are based on magnetic confinement of plasma to provide the ideal conditions for efficient thermonuclear fusion in well controlled surroundings. One important aspect is the control of instabilities that occur in the edge region of the plasma and lead to an ejection of huge amounts of energy. Magnetic perturbation fields which are resonant in the plasma edge are found to modify the plasma favourably and reduce the impact of these instabilities. This dissertation focuses on the effects of resonant magnetic perturbation fields on the ejected energy as well as on the drawbacks of these perturbation fields. The transient energy ejection which is triggered by the instabilities causes extreme heat loads on the wall components in fusion devices. Therefore, it is crucial to understand how resonant magnetic perturbation fields affect the heat load deposition. Furthermore, the impact of resonant magnetic perturbation fields on the confinement of fast ions is an important aspect as fast ions are still required to be well confined in order to avoid additional wall loads and increase the fusion efficiency. Recent upgrades on the Joint European Torus allow for a detailed study of the heat load deposition profiles caused by transient events. Throughout this work, the new features are used for the study of the modifications of the transient heat load depositions that occur if resonant magnetic perturbation fields are applied. This leads to a further understanding of the processes involved during the plasma edge instabilities. Additionally, an alternative method using lower hybrid waves for applying resonant magnetic perturbations is investigated. Furthermore, a new diagnostic, capable of detecting fast ion

Determination of Zinc Ions in Environmental Samples by Dispersive Liquid- Liquid Micro Extraction and Atomic Absorption Spectroscopy

Directory of Open Access Journals (Sweden)

F. Arabi

2012-11-01

Full Text Available In this work preconcentration of the Zn ions was investigated in water sample by Dispersive liquid- liquid micro extraction (DLLME using chloroform as an extraction solvent, methanol as a disperser solvent and 8-Hydroxyquinoline as a chelating agent. The determination of extracted ions was done by graphite furnace atomic absorption spectrometry. The influence of various analytical parameters including pH, extraction and disperser solvent type and volume and concentration of the chelating agent on the extraction efficiency of analyses was investigated. After extraction, the enrichment factor was 26 and the detection limit of the method was 0.0033 µg l-1 and the relative standard deviations (R.S.D for five determinations of 1 ng/ml Zn were 7.41%. 

Review of particle-in-cell modeling for the extraction region of large negative hydrogen ion sources for fusion

Science.gov (United States)

Wünderlich, D.; Mochalskyy, S.; Montellano, I. M.; Revel, A.

2018-05-01

Particle-in-cell (PIC) codes are used since the early 1960s for calculating self-consistently the motion of charged particles in plasmas, taking into account external electric and magnetic fields as well as the fields created by the particles itself. Due to the used very small time steps (in the order of the inverse plasma frequency) and mesh size, the computational requirements can be very high and they drastically increase with increasing plasma density and size of the calculation domain. Thus, usually small computational domains and/or reduced dimensionality are used. In the last years, the available central processing unit (CPU) power strongly increased. Together with a massive parallelization of the codes, it is now possible to describe in 3D the extraction of charged particles from a plasma, using calculation domains with an edge length of several centimeters, consisting of one extraction aperture, the plasma in direct vicinity of the aperture, and a part of the extraction system. Large negative hydrogen or deuterium ion sources are essential parts of the neutral beam injection (NBI) system in future fusion devices like the international fusion experiment ITER and the demonstration reactor (DEMO). For ITER NBI RF driven sources with a source area of 0.9 × 1.9 m2 and 1280 extraction apertures will be used. The extraction of negative ions is accompanied by the co-extraction of electrons which are deflected onto an electron dump. Typically, the maximum negative extracted ion current is limited by the amount and the temporal instability of the co-extracted electrons, especially for operation in deuterium. Different PIC codes are available for the extraction region of large driven negative ion sources for fusion. Additionally, some effort is ongoing in developing codes that describe in a simplified manner (coarser mesh or reduced dimensionality) the plasma of the whole ion source. The presentation first gives a brief overview of the current status of the ion

Extraction of pulsed ion beams from an anode covered with liquid material

International Nuclear Information System (INIS)

Kitamura, Akira; Yano, Syukuro

1982-01-01

In order to extend the life of anodes of pulsed ion diodes, a trial was made to extract ions from a plasma created by surface flashover on the oil-covered anode. The diode with this anode worked well as a so-called pinched electron beam diode. Production of proton beams of 10 kA with energies of about 400 keV was confirmed by measurements with biased ion collectors and those of prompt γ-rays from the reaction 19 F(p,γα) 16 O. Substantial reduction of damage and substantial extension of the life of the anode disc were realized. (author)

Activity assay of mangosteen (Garcinia mangostana L.) pericarp extract for decreasing fasting blood cholesterol level and lipid peroxidation in type-2 diabetic mice

Science.gov (United States)

Husen, Saikhu Akhmad; Winarni, Dwi; Khaleyla, Firas; Kalqutny, Septian Hary; Ansori, Arif Nur Muhammad

2017-09-01

This study aimed to explore the activity of pericarp extract of mangosteen (Garcinia mangostana L.). Mangosteen pericarp contains various active compounds which are beneficial for human health. In-vivo antioxidant assay of pericarp extract was carried out using 3-4 month male mice of strain BALB/c weighed 30-40 g. The mice were divided into two groups: normal control (KN) group and STZ-induced diabetic group. STZ induction was performed using multiple low-dose method 30 mg/kg body weight treated daily for five consecutive days. Diabetic group was separated into two subgroups: diabetic control (KD), metformin control (KM), and crude extract treatment subgroups. The fasting blood glucose and the cholesterol level were measured before and after lard treatment, we also did it on the first, seventh, and fourteenth day of mangosteen pericarp crude extract treatment. The mice were treated with mangosteen pericarp crude extract for 14 days. The MDA level of the fasting blood serum was measured. The body weight and fasting blood cholesterol level before and after lard treatment were analyzed by t-test, whereas, the fasting blood cholesterol and the MDA level were analyzed using one-way variant analysis continued with Duncan test. The correlation between the increasing body weight and the fasting blood cholesterol level was determined by Pearson correlation test. The results of the study showed that the administration of mangosteen pericarp crude extract was able to reduce the fasting blood cholesterol and the malondialdehide level significantly.

Effect of high ionic strength on the extraction of uranium(VI ions

Directory of Open Access Journals (Sweden)

M.K. Nazal

2014-01-01

Full Text Available Preparation and characterization of didodecylphosphoric acid (HDDPA as an extractant in toluene was carried. Mass spectroscopy showed that the monomer peak at 457.4 amu [M–Na+] is double that of the dimer at 891.9 amu [M–M–Na+] and the monomer molecules concentration dominate the dimer molecules in toluene. HDDPA was used as an extractant for the extraction of U(VI ion from perchlorate and nitrate media that have ionic strength (1.00, 3.00, 5.00, 7.00 M. The effect of HDDPA concentration, pcH, ionic strength of supporting electrolytes, and temperature in the range 15–45 °C on the extraction process have been studied. The stoichiometry of the extraction of U(VI ion, the free energy change (ΔG, the enthalpy change (ΔH, the entropy change (ΔS, and Kex at different ionic strength have been calculated. The formula of the complexes, which were formed has been established to be UO2(X(R2(HR2 at pcH equal 2.00 and UO2(X(R2(HR2 and UO2(X(R2 at pcH = 1.00, where (X isClO4- orNO3- and (HR2 is didodecylphosphoric acid monomer, (R2 is the deprotonated didodecylphosphoric acid, where R is the dodecyl group.

Extraction design and low energy beam transport optimization of space charge dominated multispecies ion beam sources

International Nuclear Information System (INIS)

Delferriere, O.; De Menezes, D.

2004-01-01

In all accelerator projects, the low energy part of the accelerator has to be carefully optimized to match the beam characteristic requirements of the higher energy parts. Since 1994 with the beginning of the Injector of Protons for High Intensity (IPHI) project and Source of Light Ions with High Intensities (SILHI) electron cyclotron resonance (ECR) ion source development at CEA/Saclay, we are using a set of two-dimensional (2D) codes for extraction system optimization (AXCEL, OPERA-2D) and beam transport (MULTIPART). The 95 keV SILHI extraction system optimization has largely increased the extracted current, and improved the beam line transmission. From these good results, a 130 mA D + extraction system for the International Fusion Material Irradiation Facility project has been designed in the same way as SILHI one. We are also now involved in the SPIRAL 2 project for the building of a 40 keV D + ECR ion source, continuously tunable from 0.1 to 5 mA, for which a special four-electrode extraction system has been studied. In this article we will describe the 2D design process and present the different extraction geometries and beam characteristics. Simulation results of SILHI H + beam emittance will be compared with experimental measurements

Solvent extraction of some metal ions by dithiocarbamate types of chemically modified lipophilic chitosan

International Nuclear Information System (INIS)

Inoue, K.; Nakagawa, H.; Naganawa, H.; Tachimori, S.

2001-01-01

Chitosan is a basic polysaccharide containing primary amino groups with high reactivity. we prepared O,O'-decanoyl chitosan and dithiocarbamate O,O'-decanoyl chitosan; the former was soluble in chloroform and toluene, while latter was soluble not only these diluents but also in some aliphatic diluents such as hexane and kerosene which are employed in commercial scale solvent extraction. Solvent extraction by dithiocarbamate O,O'-decanoyl chitosan in kerosene was tested for some base metal ions from sulfuric acid solution. The sequence of selectivity for these metal ions was found to be as follows: Cu(II) >> Ni(II) > Cd(II) ∼ Fe(III) > Co(II) ∼ Zn(II). Copper(II) was quantitatively extracted at pH > 1 and quantitatively stripped with 2 M sulfuric acid solution. Solvent extraction of silver(I) and gold(III) from hydrochloric acid as well as lanthanides and americium(III) from nitrate solution were also tested. Americium was selectively extracted over trivalent lanthanides, suggesting a high possibility for the final treatment of high level radioactive wastes. (authors)

Light ion beam transport research at NRL

International Nuclear Information System (INIS)

Hinshelwood, D.D.; Boller, J.R.; Cooperstein, G.

1996-01-01

Transport of light ion beams through low-pressure background gas is under investigation at NRL in support of the light-ion ICF program at Sandia National Laboratories. Scaling experiments and the field solver/orbit code ATHETA have been used to design and construct a focusing, extraction applied-B diode for transport experiments. An active anode source has been developed to provide a high proton fraction in the ion beam and a fast ion turn-on time. A very sensitive Zeeman diagnostic is being developed to determine the net current distribution in the beam/transport system. Both analytical and numerical techniques using several codes are being applied to transport modeling, leading to the capability of full system studies. (author). 1 tab., 5 figs., 10 refs

Light ion beam transport research at NRL

Energy Technology Data Exchange (ETDEWEB)

Hinshelwood, D D; Boller, J R; Cooperstein, G [Naval Research Lab., Washington, DC (United States). Plasma Physics Div.; and others

1997-12-31

Transport of light ion beams through low-pressure background gas is under investigation at NRL in support of the light-ion ICF program at Sandia National Laboratories. Scaling experiments and the field solver/orbit code ATHETA have been used to design and construct a focusing, extraction applied-B diode for transport experiments. An active anode source has been developed to provide a high proton fraction in the ion beam and a fast ion turn-on time. A very sensitive Zeeman diagnostic is being developed to determine the net current distribution in the beam/transport system. Both analytical and numerical techniques using several codes are being applied to transport modeling, leading to the capability of full system studies. (author). 1 tab., 5 figs., 10 refs.

Investigation of triply excited states of Li-like ions in fast ion-atom collisions by zero-degree Auger projectile electron spectroscopy

International Nuclear Information System (INIS)

Zouros, T.J.M.; Benis, E.P.; Zamkov, M.; Lin, C.D.; Lee, T.G.; Richard, P.; Gorczyca, T.W.; Morishita, T.

2005-01-01

The production of triply excited states of Li-like systems has recently been extended beyond the lithium atom using two different ion-atom collisional techniques: (a) Triple-electron capture into 2s2p 2 and 2p 3 states of F 6+ formed in fast collisions of bare F 9+ ions with Ar and Kr atoms and (b) 180 deg. resonant scattering of quasi-free electrons of H 2 from the 1s2s 3 S metastable state of He-like B, C, N, O and F ions via the 2s2p 2 2 D resonance. Autoionization energies, decay branching ratios and production cross sections for these states were measured using zero-degree Auger projectile electron spectroscopy and compared to theoretical calculations using hyperspherical close coupling (HSCC) and R-matrix methods

Performance limits of ion extraction systems with non-circular apertures

Energy Technology Data Exchange (ETDEWEB)

Shagayda, A., E-mail: shagayda@gmail.com; Madeev, S. [Keldysh Research Centre, Onezhskaya, 8, 125438 Moscow (Russian Federation)

2016-04-15

A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

Performance limits of ion extraction systems with non-circular apertures.

Science.gov (United States)

Shagayda, A; Madeev, S

2016-04-01

A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

Performance limits of ion extraction systems with non-circular apertures

Science.gov (United States)

Shagayda, A.; Madeev, S.

2016-04-01

A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

Performance limits of ion extraction systems with non-circular apertures

International Nuclear Information System (INIS)

Shagayda, A.; Madeev, S.

2016-01-01

A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

Fast neutron scintillation spectrometer in a heavy ion accelerator

International Nuclear Information System (INIS)

Blinov, M.V.; Gavrilov, B.P.; Ivannikova, L.L.; Kozulin, Eh.M.; Mozhaev, A.N.; Tyurin, G.P.

1984-01-01

Scintillation fast neutron spectrometer in a heavy ion accelerator is described in short. The spectrometer is used to measure characteristics of neutrons emitted in heavy ion interaction with different nuclei. Experiment was performed on the base of particle flight from 0.7 up to 2 m. Within the angle range of 0-150 deg. The technique is based on recording of two-dimensional neutron spectra obtained due to combination of the time-of-flight method and the method of recoil proton energy detection. Two measuring channels were used in the spectrometer. Each channel comprise both amplitude and time tracks. Detector on the base microchannel plates (MCP) generated a signal in passing the next ion bunch was used in order to obtain the time mark. Data from the scintillation block are recorded with respect to three parameters: recoil proton amplitude, time of neutron or γ-quantum arrival in respect of MCP-sensor pulse. Apparatus is carried out within the CAMAC standard. The spectrometer calibration within the 1-20 MeV neutron range was conducted in the Van-de-Graaf accelerator, and for higher energies - with the use of lightguides. Spectrometer time resolution for neutron energies of 0.5-50 MeV constituted 1.5-1.8 ns. The above measuring of neutron spectra from 1 /H2C+ 181 Ta and sup(20, 22)Ne+sup(181)Ta reaction have revealed a possibility of the experiment organization in heavy ion accelerators in the presence of strong neutron and γ-fields. Organization of multi-dimensional analysis combining two methods allows one to separate accelerator cycle, a region of the most reliable information, free of a low-energy gamma background and limited both by a dynamic threshold and a region of permissible energy values

Absolute charge-changing cross sections for fast helium ions-C sub 6 sub 0 collisions

CERN Document Server

Nose, K; Shiraishi, K; Keizaki, T; Itoh, A

2003-01-01