Fast ion beam-laser interactions

International Nuclear Information System (INIS)

Berry, H.G.; Young, L.; Engstroem, L.; Hardis, J.E.; Somerville, L.P.; Ray, W.J.; Kurtz, C.

1985-01-01

The authors are using collinear laser excitation of fast ion beams to study a number of atomic structure problems. The problems include the determination of fine and hyperfine structure in light positive and negative ions, plus measurements of absolute wavelengths of light from two-electron ions. In addition the authors intend to use a similar experimental arrangement to study excitation and decay of high Rydberg states first in the absence of fields and then in crossed electric and magnetic fields

Fast Ion Collective Thomson Scattering Diagnostic for ITER

DEFF Research Database (Denmark)

Korsholm, Søren Bang; Bindslev, Henrik; Furtula, Vedran

2008-01-01

In the era of high power and burning plasma fusion experiments with significant populations of fast particles, the diagnosis of fast ion dynamics becomes an important topic. In ITER, populations of fast ions due to ICRH and NBI, as well as fusion born alphas will carry a significant fraction...... of mock-up measurements have brought the design towards a four mirror quasi-optical solution. The development as well as the present design will be presented....

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)

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 ...

Fast and precise method of contingency ranking in modern power system

DEFF Research Database (Denmark)

Rather, Zakir Hussain; Chen, Zhe; Thøgersen, Paul

2011-01-01

Contingency Analysis is one of the most important aspect of Power System Security Analysis. This paper presents a fast and precise method of contingency ranking for effective power system security analysis. The method proposed in this research work takes due consideration of both apparent power o...... is based on realistic approach taking practical situations into account. Besides taking real situations into consideration the proposed method is fast enough to be considered for on-line security analysis.......Contingency Analysis is one of the most important aspect of Power System Security Analysis. This paper presents a fast and precise method of contingency ranking for effective power system security analysis. The method proposed in this research work takes due consideration of both apparent power...

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 and reliable method for computing free-bound emission coefficients for hydrogenic ions

Energy Technology Data Exchange (ETDEWEB)

Sarmiento, A; Canto, J

1985-12-01

An approximate formula for the computation of the free-bound emission coefficient for hydrogenic ions is presented. The approximation is obtained through a manipulation of the (free-bound) Gaunt factor which intentionally distinguish the dependence on frequency from the dependence on temperature and ionic composition. Numerical tests indicate that the derived formula is very precise, fast and easy to use, making the calculation of the free-bound contribution from an ionized region of varying temperature and ionic composition a very simple and time-saving task.

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...

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)

Progress on precision measurements of inner shell transitions in highly charged ions at an ECR ion source

Energy Technology Data Exchange (ETDEWEB)

Szabo, Csilla I.; Indelicato, Paul; LeBigot, Eric-Olivier; Vallette, Alexandre; Amaro, Pedro; Guerra, Mauro; Gumberidze, Alex [Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, Universite Pierre et Marie Curie- Paris 6, Case 74, 4 place Jussieu, F-75005 Paris (France); Centro de Fisica Atomica, CFA, Departamento de Fisica (Portugal); Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, Universite Pierre et Marie Curie- Paris 6, Case 74, 4 place Jussieu, F-75005 Paris (France)

2012-05-25

Inner shell transitions of highly charged ions produced in the plasma of an Electron Cyclotron Resonance Ion Source (ECRIS) were observed the first time by a Double Crystal Spectrometer (DCS). The DCS is a well-used tool in precision x-ray spectroscopy due to its ability of precision wavelength measurement traced back to a relative angle measurement. Because of its requirement for a bright x-ray source the DCS has not been used before in direct measurements of highly charged ions (HCI). Our new precision measurement of inner shell transitions in HCI is not just going to provide new x-ray standards for quantum metrology but can also give information about the plasma in which the ions reside. Ionic temperatures and with that the electron density can be determined by thorough examination of line widths measured with great accuracy.

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.

Precision laser spectroscopy of highly charged ions

International Nuclear Information System (INIS)

Kuehl, T.; Borneis, S.; Becker, S.; Dax, A.; Engel, T.; Grieser, R.; Huber, G.; Klaft, I.; Klepper, O.; Kohl, A.; Marx, D.; Meier, K.; Neumann, R.; Schmitt, F.; Seelig, P.; Voelker, L.

1996-01-01

Recently, intense beams of highly charged ions have become available at heavy ion cooler rings. The obstacle for producing these highly interesting candidates is the large binding energy of K-shell electrons in heavy systems in excess of 100 keV. One way to remove these electrons is to strip them off by passing the ion through material. In the cooler ring, the ions are cooled to a well defined velocity. At the SIS/ESR complex it is possible to produce, store, and cool highly charged ions up to bare uranium with intensities exceeding 10 8 atoms in the ring. This opens the door for precision laser spectroscopy of hydrogenlike-heavy ions, e.g. 209 Bi 82+ , and allows to examine the interaction of the single electron with the large fields of the heavy nucleus, exceeding any artificially produced electric and magnetic fields by orders of magnitude. In the electron cooler the interaction of electrons and highly charged ions otherwise only present in the hottest plasmas can be studied. (orig.)

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

ATLAS: a proposal for a precision heavy ion accelerator at Argonne National Laboratory

Energy Technology Data Exchange (ETDEWEB)

None

1978-02-01

The objective of the proposed Argonne Tandem-Linac Accelerator System (ATLAS) is to provide precision beams of heavy ions for nuclear physics research in the region of projectile energies comparable to nuclear binding energies (5-25 MeV/A). By using the demonstrated potential of superconducting rf technology, beams of exceptional quality and flexibility can be obtained. The system is designed to provide beams with tandem-like energy resolution and ease of energy variation, the energy range is comparable to that of a approx. 50 MV tandem and, in addition, the beam will be bunched into very short (approx. 50 psec) pulses, permitting fast-timing measurements that can open up major new experimental approaches.

ATLAS: a proposal for a precision heavy ion accelerator at Argonne National Laboratory

International Nuclear Information System (INIS)

1978-02-01

The objective of the proposed Argonne Tandem-Linac Accelerator System (ATLAS) is to provide precision beams of heavy ions for nuclear physics research in the region of projectile energies comparable to nuclear binding energies (5-25 MeV/A). By using the demonstrated potential of superconducting rf technology, beams of exceptional quality and flexibility can be obtained. The system is designed to provide beams with tandem-like energy resolution and ease of energy variation, the energy range is comparable to that of a approx. 50 MV tandem and, in addition, the beam will be bunched into very short (approx. 50 psec) pulses, permitting fast-timing measurements that can open up major new experimental approaches

A fast and reliable method for computing free-bound emission coefficients for hydrogenic ions

International Nuclear Information System (INIS)

Sarmiento, A.; Canto, J.

1985-01-01

An approximate formula for the computation of the free-bound emission coefficient for hydrogenic ions is presented. The approximation is obtained through a manipulation of the (free-bound) Gaunt factor which intentionally distinguish the dependence on frequency from the dependence on temperature and ionic composition. Numerical tests indicate that the derived formula is very precise, fast and easy to use, making the calculation of the free-bound contribution from an ionized region of varying temperature and ionic composition a very simple and time-saving task. (author)

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-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

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...

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.

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

Fast and sensitive detection of indels induced by precise gene targeting

DEFF Research Database (Denmark)

Yang, Zhang; Steentoft, Catharina; Hauge, Camilla

2015-01-01

The nuclease-based gene editing tools are rapidly transforming capabilities for altering the genome of cells and organisms with great precision and in high throughput studies. A major limitation in application of precise gene editing lies in lack of sensitive and fast methods to detect...... and characterize the induced DNA changes. Precise gene editing induces double-stranded DNA breaks that are repaired by error-prone non-homologous end joining leading to introduction of insertions and deletions (indels) at the target site. These indels are often small and difficult and laborious to detect...

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...

A Fast GPU-accelerated Mixed-precision Strategy for Fully NonlinearWater Wave Computations

DEFF Research Database (Denmark)

Glimberg, Stefan Lemvig; Engsig-Karup, Allan Peter; Madsen, Morten G.

2011-01-01

We present performance results of a mixed-precision strategy developed to improve a recently developed massively parallel GPU-accelerated tool for fast and scalable simulation of unsteady fully nonlinear free surface water waves over uneven depths (Engsig-Karup et.al. 2011). The underlying wave......-preconditioned defect correction method. The improved strategy improves the performance by exploiting architectural features of modern GPUs for mixed precision computations and is tested in a recently developed generic library for fast prototyping of PDE solvers. The new wave tool is applicable to solve and analyze...

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)

High-precision x-ray spectroscopy of highly charged ions with microcalorimeters

International Nuclear Information System (INIS)

Kraft-Bermuth, S; Andrianov, V; Bleile, A; Echler, A; Egelhof, P; Grabitz, P; Ilieva, S; Kiselev, O; Meier, J; Kilbourne, C; McCammon, D

2013-01-01

The precise determination of the energy of the Lyman α1 and α2 lines in hydrogen-like heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. To improve the experimental precision, the new detector concept of microcalorimeters is now exploited for such measurements. Such detectors consist of compensated-doped silicon thermistors and Pb or Sn absorbers to obtain high quantum efficiency in the energy range of 40–70 keV, where the Doppler-shifted Lyman lines are located. For the first time, a microcalorimeter was applied in an experiment to precisely determine the transition energy of the Lyman lines of lead ions at the experimental storage ring at GSI. The energy of the Ly α1 line E(Ly-α1, 207 Pb 81+ ) = (77937 ± 12 stat ± 25 syst ) eV agrees within error bars with theoretical predictions. To improve the experimental precision, a new detector array with more pixels and better energy resolution was equipped and successfully applied in an experiment to determine the Lyman-α lines of gold ions 197 Au 78+ . (paper)

Fine structures of atomic excited states: precision atomic spectroscopy and electron-ion collision process

International Nuclear Information System (INIS)

Gao Xiang; Cheng Cheng; Li Jiaming

2011-01-01

Scientific research fields for future energies such as inertial confinement fusion researches and astrophysics studies especially with satellite observatories advance into stages of precision physics. The relevant atomic data are not only enormous but also of accuracy according to requirements, especially for both energy levels and the collision data. The fine structure of high excited states of atoms and ions can be measured by precision spectroscopy. Such precision measurements can provide not only knowledge about detailed dynamics of electron-ion interactions but also a bench mark examination of the accuracy of electron-ion collision data, especially incorporating theoretical computations. We illustrate that by using theoretical calculation methods which can treat the bound states and the adjacent continua on equal footing. The precision spectroscopic measurements of excited fine structures can be served as stringent tests of electron-ion collision data. (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

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

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.

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)

Feasibility of the Precise Energy Calibration for Fast Neutron Spectrometers

Science.gov (United States)

Gaganov, V. V.; Usenko, P. L.; Kryzhanovskaja, M. A.

2017-12-01

Computational studies aimed at improving the accuracy of measurements performed using neutron generators with a tritium target were performed. A measurement design yielding an extremely narrow peak in the energy spectrum of DT neutrons was found. The presence of such a peak establishes the conditions for precise energy calibration of fast-neutron spectrometers.

High Precision Fast Projective Synchronization for Chaotic Systems with Unknown Parameters

Science.gov (United States)

Nian, Fuzhong; Wang, Xingyuan; Lin, Da; Niu, Yujun

2013-08-01

A high precision fast projective synchronization method for chaotic systems with unknown parameters was proposed by introducing optimal matrix. Numerical simulations indicate that the precision be improved about three orders compared with other common methods under the same condition of software and hardware. Moreover, when average error is less than 10-3, the synchronization speed is 6500 times than common methods, the iteration needs only 4 times. The unknown parameters also were identified rapidly. The theoretical analysis and proof also were given.

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.

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

Precision experiments with rare isotopes with LEBIT at MSU

Energy Technology Data Exchange (ETDEWEB)

Schury, P.; Bollen, G.; Ringle, R.; Sun, T. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Michigan State University, Department of Physics and Astronomy, East Lansing, MI (United States); Davies, D.A.; Morrissey, D.J. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Michigan State University, Department of Chemistry, East Lansing, MI (United States); Doemer, A.; Prinke, A. [Michigan State University, Department of Physics and Astronomy, East Lansing, MI (United States); Lawton, D.; Ottarson, J.; Schwarz, S.; Weissman, L. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States)

2005-09-01

The Low-Energy Beam and Ion Trap facility LEBIT at the NSCL is in the final phase of commissioning. Gas stopping of fast fragment beams and modern ion manipulation techniques are used to provide beams for high-precision mass measurements and other experiments. The status of the facility and the result of first test mass measurements on stable krypton isotopes are presented. (orig.)

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.

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)

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

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)

Fast and sensitive determination of Sr-90 and SR-89 activity in milk by ion-chromatography and liquid scintillation

International Nuclear Information System (INIS)

Figueiredo, V.; Herrmann, A.

1992-01-01

A method for fast and exact determination of both strontium isotopes in milk and other foodstuffs, combination high performance ion chromatographic separation with by liquid scintillation counting, which enables the desired results to be obtained with very satisfactory precision and reproducibility within 24 hours, has been developed. The lowest detectable activity lies by 3 Bq/liter for Sr-90 and 1 Bq/liter for Sr-89 which is satisfactory for assessing a situation in a time crisis. (author)

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

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)

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

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

Precise fabrication of a 5 nm graphene nanopore with a helium ion microscope for biomolecule detection

Science.gov (United States)

Deng, Yunsheng; Huang, Qimeng; Zhao, Yue; Zhou, Daming; Ying, Cuifeng; Wang, Deqiang

2017-01-01

We report a scalable method to fabricate high-quality graphene nanopores for biomolecule detection using a helium ion microscope (HIM). HIM milling shows promising capabilities for precisely controlling the size and shape, and may allow for the potential production of nanopores at wafer scale. Nanopores could be fabricated at different sizes ranging from 5 to 30 nm in diameter in few minutes. Compared with the current solid-state nanopore fabrication techniques, e.g. transmission electron microscopy, HIM is fast. Furthermore, we investigated the exposure-time dependence of graphene nanopore formation: the rate of pore expansion did not follow a simple linear relationship with exposure time, but a fast expansion rate at short exposure time and a slow rate at long exposure time. In addition, we performed biomolecule detection with our patterned graphene nanopore. The ionic current signals induced by 20-base single-stranded DNA homopolymers could be used as a basis for homopolymer differentiation. However, the charge interaction of homopolymer chains with graphene nanopores, and the conformations of homopolymer chains need to be further considered to improve the accuracy of discrimination.

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 beam radiofrequency spectroscopy

International Nuclear Information System (INIS)

Pipkin, F.M.

1983-01-01

The combination of a fast atom or ion beam derived from a small accelerator with radiofrequency spectroscopy methods provides a powerful method for measuring the fine structure of atomic and molecular systems. The fast beam makes possible measurements in which two separated oscillatory fields are used to obtain resonance lines whose widths are less than the natural line width due to the lifetimes of the states. The separated oscillatory field lines have, in addition, a number of features which make possible measurements with greater precision and less sensitivity to systematic errors. The fast beam also makes accessible multiple photon radiofrequency transitions whose line width is intrinsically narrower than that of the single photon transitions and which offer great potential for high precision measurements. This report focuses on the techniques and their promise. Recent measurements of the fine structure of H and He + are used as illustrations

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

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

Laser cooled ion beams and strongly coupled plasmas for precision experiments

International Nuclear Information System (INIS)

Bussmann, Michael

2008-01-01

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C 3+ ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged 24 Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

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

Laser cooled ion beams and strongly coupled plasmas for precision experiments

Energy Technology Data Exchange (ETDEWEB)

Bussmann, Michael

2008-03-17

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C{sup 3+} ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged {sup 24}Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

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.

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.

Precision Isotope Shift Measurements in Calcium Ions Using Quantum Logic Detection Schemes.

Science.gov (United States)

Gebert, Florian; Wan, Yong; Wolf, Fabian; Angstmann, Christopher N; Berengut, Julian C; Schmidt, Piet O

2015-07-31

We demonstrate an efficient high-precision optical spectroscopy technique for single trapped ions with nonclosed transitions. In a double-shelving technique, the absorption of a single photon is first amplified to several phonons of a normal motional mode shared with a cotrapped cooling ion of a different species, before being further amplified to thousands of fluorescence photons emitted by the cooling ion using the standard electron shelving technique. We employ this extension of the photon recoil spectroscopy technique to perform the first high precision absolute frequency measurement of the 2D(3/2)→2P(1/2) transition in calcium, resulting in a transition frequency of f=346 000 234 867(96)  kHz. Furthermore, we determine the isotope shift of this transition and the 2S(1/2)→2P(1/2) transition for 42Ca+, 44Ca+, and 48Ca+ ions relative to 40Ca+ with an accuracy below 100 kHz. Improved field and mass shift constants of these transitions as well as changes in mean square nuclear charge radii are extracted from this high resolution data.

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.

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.

Fast and Precise Beam Energy Measurement using Compton Backscattering at e+e- Colliders

CERN Document Server

Kaminskiy, V V; Muchnoi, N Yu; Zhilich, V N

2017-01-01

The report describes a method for a fast and precise beam energy measurement in the beam energy range 0.5-2 GeV and its application at various e+e- colliders. Low-energy laser photons interact head-on with the electron or positron beam and produce Compton backscattered photons whose energy is precisely measured by HPGe detector. The method allows measuring the beam energy with relative accuracy of ∼2-5.10-5. The method was successfully applied at VEPP-4M, VEPP-3, VEPP-2000 (BINP, Russia) and BEPC-II (IHEP, China).

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

Precise positioning of an ion in an integrated Paul trap-cavity system using radiofrequency signals

Science.gov (United States)

Kassa, Ezra; Takahashi, Hiroki; Christoforou, Costas; Keller, Matthias

2018-03-01

We report a novel miniature Paul ion trap design with an integrated optical fibre cavity which can serve as a building block for a fibre-linked quantum network. In such cavity quantum electrodynamic set-ups, the optimal coupling of the ions to the cavity mode is of vital importance and this is achieved by moving the ion relative to the cavity mode. The trap presented herein features an endcap-style design complemented with extra electrodes on which additional radiofrequency voltages are applied to fully control the pseudopotential minimum in three dimensions. This method lifts the need to use three-dimensional translation stages for moving the fibre cavity with respect to the ion and achieves high integrability, mechanical rigidity and scalability. Not based on modifying the capacitive load of the trap, this method leads to precise control of the pseudopotential minimum allowing the ion to be moved with precisions limited only by the ion's position spread. We demonstrate this by coupling the ion to the fibre cavity and probing the cavity mode profile.

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...

Demonstration of a Fast, Precise Propane Measurement Using Infrared Spectroscopy

Science.gov (United States)

Zahniser, M. S.; Roscioli, J. R.; Nelson, D. D.; Herndon, S. C.

2016-12-01

Propane is one of the primary components of emissions from natural gas extraction and processing activities. In addition to being an air pollutant, its ratio to other hydrocarbons such as methane and ethane can serve as a "fingerprint" of a particular facility or process, aiding in identifying emission sources. Quantifying propane has typically required laboratory analysis of flask samples, resulting in low temporal resolution and making plume-based measurements infeasible. Here we demonstrate fast (1-second), high precision (infrared spectroscopy at 2967 wavenumbers. In addition, we explore the impact of nearby water and ethane absorption lines on the accuracy and precision of the propane measurement. Finally, we discuss development of a dual-laser instrument capable of simultaneous measurements of methane, ethane, and propane (the C1-C3 compounds), all within a small spatial package that can be easily deployed aboard a mobile platform.

A fast image encryption system based on chaotic maps with finite precision representation

International Nuclear Information System (INIS)

Kwok, H.S.; Tang, Wallace K.S.

2007-01-01

In this paper, a fast chaos-based image encryption system with stream cipher structure is proposed. In order to achieve a fast throughput and facilitate hardware realization, 32-bit precision representation with fixed point arithmetic is assumed. The major core of the encryption system is a pseudo-random keystream generator based on a cascade of chaotic maps, serving the purpose of sequence generation and random mixing. Unlike the other existing chaos-based pseudo-random number generators, the proposed keystream generator not only achieves a very fast throughput, but also passes the statistical tests of up-to-date test suite even under quantization. The overall design of the image encryption system is to be explained while detail cryptanalysis is given and compared with some existing schemes

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

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

Research on Precision Tracking on Fast Steering Mirror and Control Strategy

Science.gov (United States)

Di, Lin; Yi-ming, Wu; Fan, Zhu

2018-01-01

Fast steering mirror is a device used for controlling the beam direction precisely. Due to the short travel of the push-pull FSM, a compound fast steering mirror system driven by both limited-angle voice coil motor and push-pull FSM together is proposed. In the compound FSM system, limited-angle voice coil motor quickly swings at wide angle, while the push-pull FSM do high frequency movement in a small range, which provides the system with the high bandwidth and long travel. In the control strategy, the method of combining feed-forward control in Kalman filtering with auto-disturbance rejection control is used to improve trajectory tracking accuracy. The simulation result shows that tracking accuracy measured by the compound method can be improved by more than 5 times than that of the conventional PID.

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)

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

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.)

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

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.

The β-decay Paul trap: A radiofrequency-quadrupole ion trap for precision β-decay studies

International Nuclear Information System (INIS)

Scielzo, N.D.; Li, G.; Sternberg, M.G.; Savard, G.; Bertone, P.F.; Buchinger, F.; Caldwell, S.; Clark, J.A.; Crawford, J.; Deibel, C.M.; Fallis, J.; Greene, J.P.

2012-01-01

The β-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision β-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following β decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of β-decay angular correlations in the decay of 8 Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup α particles. Many other β-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.

The {beta}-decay Paul trap: A radiofrequency-quadrupole ion trap for precision {beta}-decay studies

Energy Technology Data Exchange (ETDEWEB)

Scielzo, N.D., E-mail: scielzo1@llnl.gov [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Li, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Sternberg, M.G.; Savard, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Bertone, P.F. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Buchinger, F. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Caldwell, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Crawford, J. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Deibel, C.M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Fallis, J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 (Canada); Greene, J.P. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); and others

2012-07-21

The {beta}-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision {beta}-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following {beta} decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of {beta}-decay angular correlations in the decay of {sup 8}Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup {alpha} particles. Many other {beta}-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.

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

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)

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.)

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)

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

NARCIS (Netherlands)

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

2008-01-01

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

Development of a shielded ion microprobe analyzer (SIMA) and its application to fast reactor fuel elements

International Nuclear Information System (INIS)

Yuji, E.; Junji, K.; Sadamu, Y.; Toshiyuki, I.

1983-01-01

A shielded ion microprobe analyzer for elemental and isotopic analyses of irradiated fast reactor fuel and fuel component has been developed and installed in an alpha-gamma hot cell. Radiation shielding of the equipment ensures the radiation dose of -7 C/kg) for 5 Ci (1.85 x 10 11 Bq) of a 60 Co source. Hot samples can be automatically transferred from the cell to the sample chamber of the analyzer. Contamination inside the equipment through sputtering of the radioactive materials can be reduced with a special device. Distribution and migration of fission products, such as 137 Cs, 138 Ba, and 90 Sr, and of fissile materials, such as 235 U and 239 Pu in irradiated mixed-oxide fuel, and isotopic ratios of the elements can be obtained very precisely and quickly

Development of a shielded ion microprobe analyzer (SIMA) and its application to fast reactor fuel elements

International Nuclear Information System (INIS)

Enokido, Y.; Itaki, T.; Komatsu, J.; Yamanouchi, S.

1983-01-01

A shielded ion microprobe analyzer for elemental and isotopic analyses of irradiated fast reactor fuel and fuel component has been developed and installed in an alpha-gamma hot cell. Radiation shielding of the equipment ensures the radiation dose of -7 C/kg) for 5 Ci (1.85 X 10 11 Bq) of a 60 Co source. Hot samples can be automatically transferred from the cell to the sample chamber of the analyzer. Contamination inside the equipment through sputtering of the radioactive materials can be reduced with a special device. Distribution and migration of fission products, such as 137 Cs, 138 Ba, and 90 Sr, and of fissile materials, such as 235 U and 239 Pu in irradiated mixed-oxide fuel, and isotopic ratios of the elements can be obtained very precisely and quickly

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)

David Bowie and the Art of Slow Innovation: A Fast-Second Winner Strategy for Biotechnology and Precision Medicine Global Development.

Science.gov (United States)

Özdemir, Vural; Patrinos, George P

2017-11-01

Original ideas and innovation cannot always be ordered like a courier service and delivered fresh to our desk at 9 am. Yet, most creativity-based organizations, careers, and professions, science and biotechnology innovation included, emphasize the speed as the prevailing ideology. But a narrow focus on speed has several and overlooked shortcomings. For example, it does not offer the opportunity to draw from, and stitch together disparate concepts and practices for truly disruptive innovation. Preventing false starts, learning from others' or our own mistakes, and customizing innovations for local community needs are difficult in a speed-hungry innovation ecosystem. We introduce a new strategy, the Fast-Second Winner, specifically in relation to global development of biotechnologies and precision medicine. This à la carte global development strategy envisions a midstream entry into the innovation ecosystem. Moreover, we draw from the works of the late David Bowie who defied rigid classifications as an artist and prolific innovator, and introduce the concept and practice of slow innovation that bodes well with the Fast-Second Winner strategy. A type of slow innovation, the Fast-Second Winner is actually fast and sustainable in the long term, and efficient by reducing false starts in new precision medicine application contexts and geographies, learning from other innovators' failures, and shaping innovations for the local community needs. The establishment of Centers for Fast-Second Innovation (CFSIs), and their funding, for example, by crowdfunding and other innovative mechanisms, could be timely for omics and precision medicine global development. If precision medicine is about tailoring drug treatments and various health interventions to individuals, we suggest to start from tailoring new ideas, and focus not only on how much we innovate but also what and how we innovate. In principle, the Fast-Second Winner can be applied to omics and other biotechnology

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.)

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...

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

Precise ion optical description of strip-line pulsed magnetic lenses

International Nuclear Information System (INIS)

Varentsov, D.; Spiller, P.; Eickhoff, H.; Hoffmann, D.H.H.

2002-01-01

A specific computer code has been developed to investigate ion optical properties of a new generation of pulsed strip-line high current magnets. The code is based on a modern 'Differential Algebra' computational technique and it is able to calculate transfer matrices of pulsed strip-line magnets up to arbitrary order. The realistic three-dimensional distribution of the magnetic field in pulsed lenses as well as all the fringing field effects are taken into account in the simulations. We have demonstrated, that for precise description of such magnets one cannot use the existing ion optical codes where ideal multipole field distributions and fringing fields, typical for conventional iron-dominated magnets are assumed. The transfer matrix elements of pulsed strip-line lenses differ significantly from those of conventional magnets, especially in higher orders

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

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)

Getting nowhere fast: trade-off between speed and precision in training to execute image-guided hand-tool movements

Directory of Open Access Journals (Sweden)

Anil Ufuk Batmaz

2016-11-01

Full Text Available Abstract Background The speed and precision with which objects are moved by hand or hand-tool interaction under image guidance depend on a specific type of visual and spatial sensorimotor learning. Novices have to learn to optimally control what their hands are doing in a real-world environment while looking at an image representation of the scene on a video monitor. Previous research has shown slower task execution times and lower performance scores under image-guidance compared with situations of direct action viewing. The cognitive processes for overcoming this drawback by training are not yet understood. Methods We investigated the effects of training on the time and precision of direct view versus image guided object positioning on targets of a Real-world Action Field (RAF. Two men and two women had to learn to perform the task as swiftly and as precisely as possible with their dominant hand, using a tool or not and wearing a glove or not. Individuals were trained in sessions of mixed trial blocks with no feed-back. Results As predicted, image-guidance produced significantly slower times and lesser precision in all trainees and sessions compared with direct viewing. With training, all trainees get faster in all conditions, but only one of them gets reliably more precise in the image-guided conditions. Speed-accuracy trade-offs in the individual performance data show that the highest precision scores and steepest learning curve, for time and precision, were produced by the slowest starter. Fast starters produced consistently poorer precision scores in all sessions. The fastest starter showed no sign of stable precision learning, even after extended training. Conclusions Performance evolution towards optimal precision is compromised when novices start by going as fast as they can. The findings have direct implications for individual skill monitoring in training programmes for image-guided technology applications with human operators.

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

Precision and accuracy in smFRET based structural studies—A benchmark study of the Fast-Nano-Positioning System

Science.gov (United States)

Nagy, Julia; Eilert, Tobias; Michaelis, Jens

2018-03-01

Modern hybrid structural analysis methods have opened new possibilities to analyze and resolve flexible protein complexes where conventional crystallographic methods have reached their limits. Here, the Fast-Nano-Positioning System (Fast-NPS), a Bayesian parameter estimation-based analysis method and software, is an interesting method since it allows for the localization of unknown fluorescent dye molecules attached to macromolecular complexes based on single-molecule Förster resonance energy transfer (smFRET) measurements. However, the precision, accuracy, and reliability of structural models derived from results based on such complex calculation schemes are oftentimes difficult to evaluate. Therefore, we present two proof-of-principle benchmark studies where we use smFRET data to localize supposedly unknown positions on a DNA as well as on a protein-nucleic acid complex. Since we use complexes where structural information is available, we can compare Fast-NPS localization to the existing structural data. In particular, we compare different dye models and discuss how both accuracy and precision can be optimized.

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

A Fast and High-precision Orientation Algorithm for BeiDou Based on Dimensionality Reduction

Directory of Open Access Journals (Sweden)

ZHAO Jiaojiao

2015-05-01

Full Text Available A fast and high-precision orientation algorithm for BeiDou is proposed by deeply analyzing the constellation characteristics of BeiDou and GEO satellites features.With the advantage of good east-west geometry, the baseline vector candidate values were solved by the GEO satellites observations combined with the dimensionality reduction theory at first.Then, we use the ambiguity function to judge the values in order to obtain the optical baseline vector and get the wide lane integer ambiguities. On this basis, the B1 ambiguities were solved. Finally, the high-precision orientation was estimated by the determinating B1 ambiguities. This new algorithm not only can improve the ill-condition of traditional algorithm, but also can reduce the ambiguity search region to a great extent, thus calculating the integer ambiguities in a single-epoch.The algorithm is simulated by the actual BeiDou ephemeris and the result shows that the method is efficient and fast for orientation. It is capable of very high single-epoch success rate(99.31% and accurate attitude angle (the standard deviation of pitch and heading is respectively 0.07°and 0.13°in a real time and dynamic environment.

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.

Tests of a Fast Plastic Scintillator for High-Precision Half-Life Measurements

Science.gov (United States)

Laffoley, A. T.; Dunlop, R.; Finlay, P.; Leach, K. G.; Michetti-Wilson, J.; Rand, E. T.; Svensson, C. E.; Grinyer, G. F.; Thomas, J. C.; Ball, G.; Garnsworthy, A. B.; Hackman, G.; Orce, J. N.; Triambak, S.; Williams, S. J.; Andreoiu, C.; Cross, D.

2013-03-01

A fast plastic scintillator detector is evaluated for possible use in an ongoing program of high-precision half-life measurements of short lived β emitters. Using data taken at TRI-UMF's Isotope Separator and Accelerator Facility with a radioactive 26Na beam, a detailed investigation of potential systematic effects with this new detector setup is being performed. The technique will then be applied to other β-decay half-life measurements including the superallowed Fermi β emitters 10C, 14O, and T = 1/2 decay of 15O.

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...

A fast and precise chemiluminescence ozone detector for eddy flux and airborne application

Directory of Open Access Journals (Sweden)

A. Zahn

2012-02-01

Full Text Available A commercially available dry chemiluminescence (CI instrument for fast and precise measurement of ozone (O₃ is specified. The sensitivity is ~9000 counts s⁻¹ per ppbv of ozone. Its precision is entirely determined by the number of photons reaching the detector (being a photomultiplier, i.e. is quantum-noise limited. The relative precision (ΔO₃/O₃ in % thus follows Poisson statistics and scales with the square root of the measurement frequency f and with the inverse O₃ mixing ratio: ΔO₃/O₃ ∝ f^0.5 · O₃^−0.5. At typical O₃ mixing ratios between 10 and 100 ppbv (and 1 bar, the precision is 0.3–1.0% at f = 10 Hz. The maximum measurement frequency is 50 Hz. The mechanical and electronic set-up as well as the instrument performance is described. Recommendations on the adequate inlet tube configuration (inlet tube length, sampling flow and on the way of calibration at stationary ground-based platforms and onboard aircraft are given.

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.

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)

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...

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.

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)

Addendum to a proposal for ATLAS: a precision heavy-ion accelerator at Argonne National Laboratory

International Nuclear Information System (INIS)

1978-12-01

This revised proposal for the construction of the Argonne Tandem-Linac Accelerator System (ATLAS) is in all essentials the same as the proposal originally presented to NUSAC in March 1978. The only differences worth mentioning are the plan to expand the experimental area somewhat more than was originally proposed and an increased cost, brought about principally by inflation. The outline presented is the same as in the original document, reproduced for the convenience of the reader. The objective of the proposed Argonne Tandem-Linac Accelerator System (ATLAS) is to provide precision beams of heavy ions for nuclear physics research in the region of projectile energies comparable to nuclear binding energies (5 to 25 MeV/A). By using the demonstrated potential of superconducting rf technology, beams of exceptional quality and flexibility can be obtained. The proposed system is designed to provide beams with tandem-like energy resolution and ease of energy variation, and the energy range is comparable to that of a approx. 50 MV tandem. In addition, the beam will be bunched into very short (approx. 50 psec) pulses, permitting fast-timing measurements that can open up major new experimental approaches

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

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).

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)

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.

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

Mats and LaSpec: High-precision experiments using ion traps and lasers at Fair

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, D.; Lallena, A.M.; Blaum, K.; Bohm, C.; Cakirli, R.B.; Crespo Lopez-Urrutia, J.R.; Eliseev, S.; Ketelaer, J.; Kreim, M.S.; Kowalska, M.; Litvinov, Y.A.; Nagy, S.; Neidherr, D.; Repp, J.; Roux, C.; Schabinger, B.; Ullrich, J.; Nortershauser, W.; Eberhardt, K.; Geppert, C.; Kramer, J.; Krieger, A.; Sanchez, R.; Ahammed, M.; Das, P.; Ray, A.; Algora, A.; Rubio, B.; Tain, J.L.; Audi, G.; Lunney, D.; Naimi, S.; Aysto, J.; Jokinen, A.; Kolhinen, V.; Moore, I.; Beck, D.; Block, M.; Geissel, H.; Heinz, S.; Herfurth, F.; Litvinov, Y.A.; Minaya-Ramirez, E.; Plab, W.R.; Quint, W.; Scheidenberger, C.; Winkler, M.; Bender, M.; Billowes, J.; Campbell, P.; Flanagan, K.T.; Schwarz, S.; Bollen, G.; Ferrer, R.; George, S.; Kester, O.; Brodeur, M.; Brunner, T.; Delheij, P.; Dilling, J.; Ettenauer, S.; Lapierre, A.; Bushaw, B.A.; Cano-Ott, D.; Martinez, T.; Cortes, G.; Gomez-Hornillos, M.B.; Dax, A.; Herlert, A.; Yordanov, D.; De, A.; Dickel, T.; Geissel, H.; Jesch, C.; Kuhl, T.; Petrick, M.; PlaB, W.R.; Scheidenberger, C.; Garcia-Ramos, J.E.; Gartzke, E.; Habs, D.; Szerypo, J.; Thirolf, P.G.; Weber, C.; Gusev, Y.; Nesterenko, D.; Novikov, Y.N.; Popov, A.; Seliverstov, M.; Vasiliev, A.; Vorobjev, G.; Heenen, P.H.; Marx, G.; Schweikhard, L.; Ziegler, F.; Hobein, M.; Schuch, R.; Solders, A.; Suhonen, M.; Huber, G.; Wendt, K.; Huyse, M.; Koudriavtsev, I.; Neyens, G.; Van Duppen, P.; Le Blanc, F.; Matos, M.; Reinhard, P.G.; Schneider, D.

2010-05-15

Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10{sup -9} can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. Decay studies in ion traps will become possible with MATS. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The accuracy of laser-spectroscopic-determined nuclear properties is very high while requirements concerning production rates are moderate. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy. Since MATS and LaSpec require high-quality low

Mats and LaSpec: High-precision experiments using ion traps and lasers at Fair

International Nuclear Information System (INIS)

Rodriguez, D.; Lallena, A.M.; Blaum, K.; Bohm, C.; Cakirli, R.B.; Crespo Lopez-Urrutia, J.R.; Eliseev, S.; Ketelaer, J.; Kreim, M.S.; Kowalska, M.; Litvinov, Y.A.; Nagy, S.; Neidherr, D.; Repp, J.; Roux, C.; Schabinger, B.; Ullrich, J.; Nortershauser, W.; Eberhardt, K.; Geppert, C.; Kramer, J.; Krieger, A.; Sanchez, R.; Ahammed, M.; Das, P.; Ray, A.; Algora, A.; Rubio, B.; Tain, J.L.; Audi, G.; Lunney, D.; Naimi, S.; Aysto, J.; Jokinen, A.; Kolhinen, V.; Moore, I.; Beck, D.; Block, M.; Geissel, H.; Heinz, S.; Herfurth, F.; Litvinov, Y.A.; Minaya-Ramirez, E.; Plab, W.R.; Quint, W.; Scheidenberger, C.; Winkler, M.; Bender, M.; Billowes, J.; Campbell, P.; Flanagan, K.T.; Schwarz, S.; Bollen, G.; Ferrer, R.; George, S.; Kester, O.; Brodeur, M.; Brunner, T.; Delheij, P.; Dilling, J.; Ettenauer, S.; Lapierre, A.; Bushaw, B.A.; Cano-Ott, D.; Martinez, T.; Cortes, G.; Gomez-Hornillos, M.B.; Dax, A.; Herlert, A.; Yordanov, D.; De, A.; Dickel, T.; Geissel, H.; Jesch, C.; Kuhl, T.; Petrick, M.; PlaB, W.R.; Scheidenberger, C.; Garcia-Ramos, J.E.; Gartzke, E.; Habs, D.; Szerypo, J.; Thirolf, P.G.; Weber, C.; Gusev, Y.; Nesterenko, D.; Novikov, Y.N.; Popov, A.; Seliverstov, M.; Vasiliev, A.; Vorobjev, G.; Heenen, P.H.; Marx, G.; Schweikhard, L.; Ziegler, F.; Hobein, M.; Schuch, R.; Solders, A.; Suhonen, M.; Huber, G.; Wendt, K.; Huyse, M.; Koudriavtsev, I.; Neyens, G.; Van Duppen, P.; Le Blanc, F.; Matos, M.; Reinhard, P.G.; Schneider, D.

2010-01-01

Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10 -9 can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. Decay studies in ion traps will become possible with MATS. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The accuracy of laser-spectroscopic-determined nuclear properties is very high while requirements concerning production rates are moderate. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy. Since MATS and LaSpec require high-quality low-energy beams

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.

High-precision hyperfine structure measurement in slow atomic ion beams by collinear laser-rf double resonance

International Nuclear Information System (INIS)

Amarjit Sen; Childs, W.J.; Goodman, L.S.

1987-01-01

A new collinear laser-ion beam apparatus for slow ions (1 to 1.5 keV) has been built for measuring the hyperfine structure of metastable levels of ions with laser-rf double resonance technique. Narrow linewidths of ∼60 kHz (FWHM) have been observed for the first time in such systems. As a first application the hyperfine structure of the 4f 7 ( 8 S 0 )5d 9 D/sub J/ 0 metastable levels of /sup 151,153/Eu + has been measured with high precision. 10 refs., 8 figs

Hamiltonian study of the response of a tokamak plasma to the ion cyclotron heating wave: minor heating and current generation by the fast wave

International Nuclear Information System (INIS)

Becoulet, A.

1990-06-01

The role of additional Heatings, such as the Ion Cyclotron Heating, is to raise magnetic fusion plasmas to higher temperatures, to satisfy the ignition condition. The understanding of the wave absorption mechanisms by the plasma first requires a precise description of the particle individual trajectories. The Hamiltonian mechanics, through action-angle variables, allows this description, and makes the computation of the wave-particle interaction easier. We then derive a quantitative evaluation of the intrinsic stochasticity for ionic trajectories perturbated by the fast wave. This stochasticity, combinated to the collisional effects, gives the validity domain for a quasilinear approximation of the evolution equation. This equation is then written under a variational formulation, and solved semi-analytically. Results conclude to the importance of the Hamiltonian chaos in the formation of the deeply anisotropic distribution tails, encountered in minority heating scenarios. Direct interaction of the electrons and the fast wave is similarly analysed. The influence of the various parameters (wave spectrum, magnetic configuration, frequency,...) is then examined in order to optimize this scenario of fast wave current drive in tokamaks [fr

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...

Towards a precise measurement of atomic parity violation in a single Ra+ ion

International Nuclear Information System (INIS)

Nuñez Portela, M.; Berg, J. E. van den; Bekker, H.; Böll, O.; Dijck, E. A.; Giri, G. S.; Hoekstra, S.; Jungmann, K.; Mohanty, A.; Onderwater, C. J. G.; Santra, B.; Schlesser, S.; Timmermans, R. G. E.; Versolato, O. O.; Wansbeek, L. W.; Willmann, L.; Wilschut, H. W.

2013-01-01

A single trapped Ra  +  (Z = 88) ion provides a very promising route towards a most precise measurement of Atomic Parity Violation (APV), since APV effects grow faster than Z 3 . This experiment promises the best determination of the electroweak coupling constant at the lowest accessible energies. Such a measurement provides a sensitive test of the Standard Model in particle physics. At the present stage of the experiment, we focus on trapping and laser cooling stable Ba  +  ions as a precursor for radioactive Ra  +  . Online laser spectroscopy of the isotopes 209 − 214 Ra  +  in a linear Paul trap has provided information on transition wavelengths, fine and hyperfine structures and excited state lifetimes as test of atomic structure calculations. Additionaly, a single trapped Ra  +  ion could function as a very stable clock.

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.)

MATS and LaSpec: High-precision experiments using ion traps and lasers at FAIR

Science.gov (United States)

Rodríguez, D.; Blaum, K.; Nörtershäuser, W.; Ahammed, M.; Algora, A.; Audi, G.; Äystö, J.; Beck, D.; Bender, M.; Billowes, J.; Block, M.; Böhm, C.; Bollen, G.; Brodeur, M.; Brunner, T.; Bushaw, B. A.; Cakirli, R. B.; Campbell, P.; Cano-Ott, D.; Cortés, G.; Crespo López-Urrutia, J. R.; Das, P.; Dax, A.; de, A.; Delheij, P.; Dickel, T.; Dilling, J.; Eberhardt, K.; Eliseev, S.; Ettenauer, S.; Flanagan, K. T.; Ferrer, R.; García-Ramos, J.-E.; Gartzke, E.; Geissel, H.; George, S.; Geppert, C.; Gómez-Hornillos, M. B.; Gusev, Y.; Habs, D.; Heenen, P.-H.; Heinz, S.; Herfurth, F.; Herlert, A.; Hobein, M.; Huber, G.; Huyse, M.; Jesch, C.; Jokinen, A.; Kester, O.; Ketelaer, J.; Kolhinen, V.; Koudriavtsev, I.; Kowalska, M.; Krämer, J.; Kreim, S.; Krieger, A.; Kühl, T.; Lallena, A. M.; Lapierre, A.; Le Blanc, F.; Litvinov, Y. A.; Lunney, D.; Martínez, T.; Marx, G.; Matos, M.; Minaya-Ramirez, E.; Moore, I.; Nagy, S.; Naimi, S.; Neidherr, D.; Nesterenko, D.; Neyens, G.; Novikov, Y. N.; Petrick, M.; Plaß, W. R.; Popov, A.; Quint, W.; Ray, A.; Reinhard, P.-G.; Repp, J.; Roux, C.; Rubio, B.; Sánchez, R.; Schabinger, B.; Scheidenberger, C.; Schneider, D.; Schuch, R.; Schwarz, S.; Schweikhard, L.; Seliverstov, M.; Solders, A.; Suhonen, M.; Szerypo, J.; Taín, J. L.; Thirolf, P. G.; Ullrich, J.; van Duppen, P.; Vasiliev, A.; Vorobjev, G.; Weber, C.; Wendt, K.; Winkler, M.; Yordanov, D.; Ziegler, F.

2010-05-01

Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique “fingerprint”. Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10-5 to below 10-8 for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an A_dvanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10-9 can be reached by employing highly-charged ions and a non

Induction of the Tn10 Precise Excision in E. coli Cells after Accelerated Heavy Ions Irradiation

CERN Document Server

Zhuravel, D V

2003-01-01

The influence of the irradiation of different kinds on the indication of the structural mutations in the bacteria Escherichia coli is considered. The regularities of the Tn10 precise excision after accelerated ^{4}He and ^{12}C ions irradiations with different linear energy transfer (LET) were investigated. Dose dependences of the survival and relative frequency of the Tn10 precise excision were obtained. It was shown, that the relative frequency of the Tn10 precise excision is the exponential function from the irradiation dose. Relative biological efficiency (RBE), and relative genetic efficiency (RGE) were calculated, and were treated as the function of the LET.

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

Ridge waveguide fabrication by combining ion implantation and precise dicing on a LiNbO{sub 3} crystal

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yu-Fan; Wang, Lei; Liu, Peng; Liu, Tao; Zhang, Lian; Huang, Dong-Ting; Wang, Xue-Lin, E-mail: xuelinwang@sdu.edu.cn

2014-05-01

A ridge waveguide structure was prepared on a z-cut LiNbO{sub 3} crystal wafer by a combined process of ion implantation and precise dicing. The single-crystal LiNbO{sub 3} was implanted at room temperature using 3 MeV oxygen ions at a fluence of 5 × 10{sup 14} ions/cm{sup 2}. After annealing to 200 °C, ridge structures were formed on the wafer surface by precise diamond blade dicing. Two different ridge widths, 8 and 10 μm, were chosen for comparison. The refractive index profile was reconstructed, and the near-field intensity distribution of the mode was recorded by a CCD camera using the end-face coupling method. FD-BPM was used to simulate the guided mode profile. Transmission and reflection optical microscopy were used to obtain micro-photograph images of the waveguide structure.

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...

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

Storage ion trap of an 'In-Flight Capture' type for precise mass measurement of radioactive nuclear reaction products and fission fragments

International Nuclear Information System (INIS)

Tarantin, N.I.

2001-01-01

Data on nuclear masses provide a basis for creating and testing various nuclear models. A tandem system of FLNR comprised of the U-400M cyclotron, the COMBAS magnetic separator and the mass-spectrometric ion trap of an 'in-flight capture' type is considered as a possible complex for producing of the short-lived nuclei in fragmentation reactions by heavy ions and for precise mass measurement of these nuclei. The plan of scientific and technical FLNR research includes a project DRIBs for producing beams of accelerated radioactive nuclear reaction products and photofission fragments. This project proposes also precise mass measurements of the fission fragment with the help of the ion trap. The in-flight entrance of the ions and their capture in the mass-spectrometric ion trap using the monochromatizing degrader, the static electric and magnetic fields and a new invention, a magnetic unidirectional transporting ventil, is considered

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

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...

Towards a precise measurement of atomic parity violation in a single Ra{sup +} ion

Energy Technology Data Exchange (ETDEWEB)

Nunez Portela, M., E-mail: nunez@kvi.nl; Berg, J. E. van den; Bekker, H.; Boell, O.; Dijck, E. A.; Giri, G. S.; Hoekstra, S.; Jungmann, K.; Mohanty, A.; Onderwater, C. J. G.; Santra, B.; Schlesser, S.; Timmermans, R. G. E.; Versolato, O. O.; Wansbeek, L. W.; Willmann, L.; Wilschut, H. W. [Kernfysisch Versneller Instituut (KVI) (Netherlands)

2013-03-15

A single trapped Ra{sup + } (Z = 88) ion provides a very promising route towards a most precise measurement of Atomic Parity Violation (APV), since APV effects grow faster than Z{sup 3}. This experiment promises the best determination of the electroweak coupling constant at the lowest accessible energies. Such a measurement provides a sensitive test of the Standard Model in particle physics. At the present stage of the experiment, we focus on trapping and laser cooling stable Ba{sup + } ions as a precursor for radioactive Ra{sup + }. Online laser spectroscopy of the isotopes {sup 209 - 214}Ra{sup + } in a linear Paul trap has provided information on transition wavelengths, fine and hyperfine structures and excited state lifetimes as test of atomic structure calculations. Additionaly, a single trapped Ra{sup + } ion could function as a very stable clock.

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

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

Precision, high dose radiotherapy: helium ion treatment of uveal melanoma

Energy Technology Data Exchange (ETDEWEB)

Saunders, W.M.; Char, D.H.; Quivey, J.M.; Castro, J.R.; Chen, G.T.Y.; Collier, J.M.; Cartigny, A.; Blakely, E.A.; Lyman, J.T.; Zink, S.R.

1985-02-01

The authors report on 75 patients with uveal melanoma who were treated by placing the Bragg peak of a helium ion beam over the tumor volume. The technique localizes the high dose region very tightly around the tumor volume. This allows critical structures, such as the optic disc and the macula, to be excluded from the high dose region as long as they are 3 to 4 mm away from the edge of the tumor. Careful attention to tumor localization, treatment planning, patient immobilization and treatment verification is required. With a mean follow-up of 22 months (3 to 60 months) the authors have had only five patients with a local recurrence, all of whom were salvaged with another treatment. Pretreatment visual acuity has generally been preserved as long as the tumor edge is at least 4 mm away from the macula and optic disc. The only serious complication to date has been an 18% incidence of neovascular glaucoma in the patients treated at our highest dose level. Clinical results and details of the technique are presented to illustrate potential clinical precision in administering high dose radiotherapy with charged particles such as helium ions or protons.

Precision, high dose radiotherapy: helium ion treatment of uveal melanoma

International Nuclear Information System (INIS)

Saunders, W.M.; Char, D.H.; Quivey, J.M.

1985-01-01

The authors report on 75 patients with uveal melanoma who were treated by placing the Bragg peak of a helium ion beam over the tumor volume. The technique localizes the high dose region very tightly around the tumor volume. This allows critical structures, such as the optic disc and the macula, to be excluded from the high dose region as long as they are 3 to 4 mm away from the edge of the tumor. Careful attention to tumor localization, treatment planning, patient immobilization and treatment verification is required. With a mean follow-up of 22 months (3 to 60 months) the authors have had only five patients with a local recurrence, all of whom were salvaged with another treatment. Pretreatment visual acuity has generally been preserved as long as the tumor edge is at least 4 mm away from the macula and optic disc. The only serious complication to date has been an 18% incidence of neovascular glaucoma in the patients treated at our highest dose level. Clinical results and details of the technique are presented to illustrate potential clinical precision in administering high dose radiotherapy with charged particles such as helium ions or protons

Integrated hybrid vibration isolator with feedforward compensation for fast high-precision positioning X/Y tables

International Nuclear Information System (INIS)

Yan, T H; Li, Q; Xu, C; Pu, H Y; Chen, X D

2010-01-01

The design, realization and control technologies of a high-performance hybrid microvibration isolator for ultra-high-precision high-speed moving X/Y tables are presented in this paper—the novel isolator with integrated passive–active high level of damping. The passive damping was implemented using air-springs in both vertical and horizontal directions, with parallel linear motors in two directions to realize the active damping and the positioning functions. It is an actual hybrid isolation system because its air-spring can also be controlled through the pneumatic loop. The isolation servo system also has fast positioning capability via the feedforward compensation for the moving tables. Compared with the conventional filtered reference type control algorithms that rely on the assumption for the adaptive filter and the controlled system, in which the disturbance is estimated from the residual signal, the feedforward compensation here shows high effectiveness of vibration isolation and high-precision positioning performance for its platform. The performance of feedforward compensation has been enhanced via an efficient state estimation adaptive algorithm, the fast Kalman filter. Finally, experimental demonstration has been shown for the prototype system and the results have verified the effectiveness of the proposed isolator system design and the adaptive control algorithm for substantially enhanced damping of the platform system with the moving X/Y tables

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.

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

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...

Accurate and precise measurement of oxygen isotopic fractions and diffusion profiles by selective attenuation of secondary ions (SASI).

Science.gov (United States)

Téllez, Helena; Druce, John; Hong, Jong-Eun; Ishihara, Tatsumi; Kilner, John A

2015-03-03

The accuracy and precision of isotopic analysis in Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) relies on the appropriate reduction of the dead-time and detector saturation effects, especially when analyzing species with high ion yields or present in high concentrations. Conventional approaches to avoid these problems are based on Poisson dead-time correction and/or an overall decrease of the total secondary ion intensity by reducing the target current. This ultimately leads to poor detection limits for the minor isotopes and high uncertainties of the measured isotopic ratios. An alternative strategy consists of the attenuation of those specific secondary ions that saturate the detector, providing an effective extension of the linear dynamic range. In this work, the selective attenuation of secondary ion signals (SASI) approach is applied to the study of oxygen transport properties in electroceramic materials by isotopic labeling with stable (18)O tracer and ToF-SIMS depth profiling. The better analytical performance in terms of accuracy and precision allowed a more reliable determination of the oxygen surface exchange and diffusion coefficients while maintaining good mass resolution and limits of detection for other minor secondary ion species. This improvement is especially relevant to understand the ionic transport mechanisms and properties of solid materials, such as the parallel diffusion pathways (e.g., oxygen diffusion through bulk, grain boundary, or dislocations) in electroceramic materials with relevant applications in energy storage and conversion devices.

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

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)

BOKASUN: a fast and precise numerical program to calculate the Master Integrals of the two-loop sunrise diagrams

OpenAIRE

Caffo, Michele; Czyz, Henryk; Gunia, Michal; Remiddi, Ettore

2008-01-01

We present the program BOKASUN for fast and precise evaluation of the Master Integrals of the two-loop self-mass sunrise diagram for arbitrary values of the internal masses and the external four-momentum. We use a combination of two methods: a Bernoulli accelerated series expansion and a Runge-Kutta numerical solution of a system of linear differential equations.

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...

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

Precision mass measurements using the Phase-Imaging Ion-Cyclotron-Resonance detection technique

CERN Document Server

Karthein, Jonas

This thesis presents the implementation and improvement of the Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) detection technique at the ISOLTRAP experiment, located at the ISOLDE / CERN, with the purpose of on-line high-precision and high-resolution mass spectrometry. Extensive simulation studies were performed with the aim of improving the phase-imaging resolution and finding the optimal position for detector placement. Following the outcome of these simulations, the detector was moved out of a region of electric-field distortion and closer to the center of the Penning trap, showing a dramatic improvement in the quality and reproducibility of the phase-imaging measurements. A new image reconstitution and analysis software for the MCP-PS detector was written in Python and ROOT and introduced in the framework of PI-ICR mass measurements. The state of the art in the field of time-of-flight ion-cyclotron-resonance measurements is illustrated through an analysis of on-line measurements of the mirror nuclei $...

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

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.

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)

Recent trends in precision measurements of atomic and nuclear properties with lasers and ion traps

Science.gov (United States)

Block, Michael

2017-11-01

The X. international workshop on "Application of Lasers and Storage Devices in Atomic Nuclei Research" took place in Poznan in May 2016. It addressed the latest experimental and theoretical achievements in laser and ion trap-based investigations of radionuclides, highly charged ions and antiprotons. The precise determination of atomic and nuclear properties provides a stringent benchmark for theoretical models and eventually leads to a better understanding of the underlying fundamental interactions and symmetries. This article addresses some general trends in this field and highlights select recent achievements presented at the workshop. Many of these are covered in more detail within the individual contributions to this special issue of Hyperfine Interactions.

Recent trends in precision measurements of atomic and nuclear properties with lasers and ion traps

Energy Technology Data Exchange (ETDEWEB)

Block, Michael, E-mail: m.block@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH (Germany)

2017-11-15

The X. international workshop on “Application of Lasers and Storage Devices in Atomic Nuclei Research” took place in Poznan in May 2016. It addressed the latest experimental and theoretical achievements in laser and ion trap-based investigations of radionuclides, highly charged ions and antiprotons. The precise determination of atomic and nuclear properties provides a stringent benchmark for theoretical models and eventually leads to a better understanding of the underlying fundamental interactions and symmetries. This article addresses some general trends in this field and highlights select recent achievements presented at the workshop. Many of these are covered in more detail within the individual contributions to this special issue of Hyperfine Interactions.

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.

CSR: a new tool for storage and cooling of keV ion beams

Energy Technology Data Exchange (ETDEWEB)

Froese, Michael; Blaum, Klaus; Crespo Lopez-Urrutia, Jose; Fellenberger, Florian; Grieser, Manfred; Kaiser, Dirk; Lange, Michael; Laux, Felix; Menk, Sebastian; Orlov, Dmitry A.; Repnow, Roland; Schroeter, Claus D.; Schwalm, Dirk; Sieber, Thomas; Ullrich, Joachim; Varju, Jozef; Hahn, Robert von; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Heber, Oded; Rappaport, Michael; Toker, Jonathan; Zajfman, Daniel [Weizman Institute of Science, Rehovot (Israel)

2009-07-01

An electrostatic Cryogenic Storage Ring (CSR) is currently being built in Heidelberg, Germany. The current status and final design of this ring, with a focus on the optimized 2 K chamber cooling, precision chamber suspension, and pumping down to extremely low pressures via cryogenic vacuum chambers will be presented. This ring will allow long storage times of highly charged ion and polyatomic molecular beams with energies in the range of keV per charge-state. Combining the long storage times with vacuum chamber temperatures approaching 2 K, infrared-active molecular ions will be radiatively cooled to their rotational ground states. Many aspects of this concept were experimentally tested with a cryogenic trap for fast ion beams (CTF), which has already demonstrated the storage of fast ion beams in a large cryogenic device. An upcoming test will investigate the effect of pre-baking the cryogenic vacuum chambers to 600 K on the cryogenic vacuum and the ion beam storage.

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.

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)

High-Precision Phenotyping of Grape Bunch Architecture Using Fast 3D Sensor and Automation.

Science.gov (United States)

Rist, Florian; Herzog, Katja; Mack, Jenny; Richter, Robert; Steinhage, Volker; Töpfer, Reinhard

2018-03-02

Wine growers prefer cultivars with looser bunch architecture because of the decreased risk for bunch rot. As a consequence, grapevine breeders have to select seedlings and new cultivars with regard to appropriate bunch traits. Bunch architecture is a mosaic of different single traits which makes phenotyping labor-intensive and time-consuming. In the present study, a fast and high-precision phenotyping pipeline was developed. The optical sensor Artec Spider 3D scanner (Artec 3D, L-1466, Luxembourg) was used to generate dense 3D point clouds of grapevine bunches under lab conditions and an automated analysis software called 3D-Bunch-Tool was developed to extract different single 3D bunch traits, i.e., the number of berries, berry diameter, single berry volume, total volume of berries, convex hull volume of grapes, bunch width and bunch length. The method was validated on whole bunches of different grapevine cultivars and phenotypic variable breeding material. Reliable phenotypic data were obtained which show high significant correlations (up to r² = 0.95 for berry number) compared to ground truth data. Moreover, it was shown that the Artec Spider can be used directly in the field where achieved data show comparable precision with regard to the lab application. This non-invasive and non-contact field application facilitates the first high-precision phenotyping pipeline based on 3D bunch traits in large plant sets.

Precision Tests of the Electroweak Interaction using Trapped Atoms and Ions

Energy Technology Data Exchange (ETDEWEB)

Melconian, Daniel George [Texas A & M Univ., College Station, TX (United States)

2017-06-21

The objective of the proposed research is to study fundamental aspects of the electroweak interaction via precision measurements in beta decay to test our current understanding of fundamental particles and forces as contained in the so-called "Standard Model" of particle physics. By comparing elegant experiments to rigorous theoretical predictions, we will either confirm the Standard Model to a higher degree and rule out models which seek to extend it, or find evidence of new physics and help guide theorists in developing the New Standard Model. The use of ion and neutral atom traps at radioactive ion beam facilities has opened up a new vista in precision low-energy nuclear physics experiments. Traps provide an ideal source of decaying atoms: they can be extremely cold (~1 mK); they are compact (~1 mm^3); and perhaps most importantly, the daughter particles escape with negligible distortions to their momenta in a scattering-free, open environment. The project is taking advantage of these technologies and applying them to precision beta-decay studies at radioactive beam facilities. The program consists of two complementary efforts: 1) Ion traps are an extremely versatile tool for purifying, cooling and bunching low-energy beams of short-lived nuclei. A large-bore (210~mm) superconducting 7-Tesla solenoid is at the heart of a Penning trap system for which there is a dedicated beamline at T-REX, the upgraded radioactive beam facility at the Cyclotron Institute, Texas A&M University. In addition to providing a general-purpose decay station, the flagship program for this system is measuring the ft-values and beta-neutrino correlation parameters from isospin T=2 superallowed beta-delayed proton decays, complimenting and expanding the already strong program in fundamental interactions at the Institute. 2) A magneto-optical trap is being used at the TRIUMF Neutral Atom Trap facility to observe the (un)polarized angular distribution parameters of isotopes of potassium. We

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.

Precise Aperture-Dependent Motion Compensation with Frequency Domain Fast Back-Projection Algorithm

Directory of Open Access Journals (Sweden)

Man Zhang

2017-10-01

Full Text Available Precise azimuth-variant motion compensation (MOCO is an essential and difficult task for high-resolution synthetic aperture radar (SAR imagery. In conventional post-filtering approaches, residual azimuth-variant motion errors are generally compensated through a set of spatial post-filters, where the coarse-focused image is segmented into overlapped blocks concerning the azimuth-dependent residual errors. However, image domain post-filtering approaches, such as precise topography- and aperture-dependent motion compensation algorithm (PTA, have difficulty of robustness in declining, when strong motion errors are involved in the coarse-focused image. In this case, in order to capture the complete motion blurring function within each image block, both the block size and the overlapped part need necessary extension leading to degeneration of efficiency and robustness inevitably. Herein, a frequency domain fast back-projection algorithm (FDFBPA is introduced to deal with strong azimuth-variant motion errors. FDFBPA disposes of the azimuth-variant motion errors based on a precise azimuth spectrum expression in the azimuth wavenumber domain. First, a wavenumber domain sub-aperture processing strategy is introduced to accelerate computation. After that, the azimuth wavenumber spectrum is partitioned into a set of wavenumber blocks, and each block is formed into a sub-aperture coarse resolution image via the back-projection integral. Then, the sub-aperture images are straightforwardly fused together in azimuth wavenumber domain to obtain a full resolution image. Moreover, chirp-Z transform (CZT is also introduced to implement the sub-aperture back-projection integral, increasing the efficiency of the algorithm. By disusing the image domain post-filtering strategy, robustness of the proposed algorithm is improved. Both simulation and real-measured data experiments demonstrate the effectiveness and superiority of the proposal.

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....

A fast isotope switching system for high energy ions

International Nuclear Information System (INIS)

Niklaus, T.R.; Sie, S.H.; Suter, G.F.

1998-01-01

A fast bouncing system for the high energy end of an Accelerator Mass Spectrometry system has been devised for the AUSTRALIS at the CSIRO HIAF laboratory. Based on a method designed for excitation function measurements, it has been adapted as an isotope sequencer for AMS at the high energy side. In this scheme, different isotopes of the same energy are deflected off axis in the orbit plane by varying amounts at the entrance to the magnet and returned to the main axis at the exit by another deflection of the same magnitude in the same plane. Synchronised with the low energy side bouncer, the system will enable isotope ratios measurements with high precision by overcoming drifts in the source, beam transport and the accelerator itself

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.

High-speed precision motion control

CERN Document Server

Yamaguchi, Takashi; Pang, Chee Khiang

2011-01-01

Written for researchers and postgraduate students in Control Engineering, as well as professionals in the Hard Disk Drive industry, this book discusses high-precision and fast servo controls in Hard Disk Drives (HDDs). The editors present a number of control algorithms that enable fast seeking and high precision positioning, and propose problems from commercial products, making the book valuable to researchers in HDDs. Each chapter is self contained, and progresses from concept to technique, present application examples that can be used within automotive, aerospace, aeronautical, and manufactu

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

High-Precision Phenotyping of Grape Bunch Architecture Using Fast 3D Sensor and Automation

Directory of Open Access Journals (Sweden)

Florian Rist

2018-03-01

Full Text Available Wine growers prefer cultivars with looser bunch architecture because of the decreased risk for bunch rot. As a consequence, grapevine breeders have to select seedlings and new cultivars with regard to appropriate bunch traits. Bunch architecture is a mosaic of different single traits which makes phenotyping labor-intensive and time-consuming. In the present study, a fast and high-precision phenotyping pipeline was developed. The optical sensor Artec Spider 3D scanner (Artec 3D, L-1466, Luxembourg was used to generate dense 3D point clouds of grapevine bunches under lab conditions and an automated analysis software called 3D-Bunch-Tool was developed to extract different single 3D bunch traits, i.e., the number of berries, berry diameter, single berry volume, total volume of berries, convex hull volume of grapes, bunch width and bunch length. The method was validated on whole bunches of different grapevine cultivars and phenotypic variable breeding material. Reliable phenotypic data were obtained which show high significant correlations (up to r2 = 0.95 for berry number compared to ground truth data. Moreover, it was shown that the Artec Spider can be used directly in the field where achieved data show comparable precision with regard to the lab application. This non-invasive and non-contact field application facilitates the first high-precision phenotyping pipeline based on 3D bunch traits in large plant sets.

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

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

Absolute charge-changing cross sections for fast helium ions passing through a C sub 6 sub 0 gas target have been measured. The measurements were carried out for incident projectile energies at 1.0MeV and 1.5MeV. The measured cross sections are compared with calculated values from Bohr-Lindhard model and Bohr model. In addition, we have obtained equilibrium charge state fractions and average equilibrium charge of helium ions passing through C sub 6 sub 0 , by using the measured cross sections.

Coulomb excitation of atoms by fast multicharged ions

International Nuclear Information System (INIS)

Yudin, G.L.

1980-01-01

Investigated is coulomb eXcitation of discrete levels of a hydrogen-like atom by a fast multicharged ion. Obtained are dependences of probabilities of channels 1S→nS and 1S→nP on the sight parameter in the zero order of sudden excitation theory. 1S-2S transition is considered in detail. Carried out are calculations for excitation of the hydrogen atom by the wholy bare carbon atom. It is shown, that at low values of excitation pr.ocess parameter eta excitation probability is a monotonously decreasing function of the impact parameter. With the growth of eta the situation is changed, and at low impact parameters the probability of 1S-2S transition is decreased. At high impact parameters approximation of sudden excitations is unacceptable, here lagging of coulomb interaction is essential

Progress Towards a High-Precision Infrared Spectroscopic Survey of the H_3^+ Ion

Science.gov (United States)

Perry, Adam J.; Hodges, James N.; Markus, Charles R.; Kocheril, G. Stephen; Jenkins, Paul A., II; McCall, Benjamin J.

2015-06-01

The trihydrogen cation, H_3^+, represents one of the most important and fundamental molecular systems. Having only two electrons and three nuclei, H_3^+ is the simplest polyatomic system and is a key testing ground for the development of new techniques for calculating potential energy surfaces and predicting molecular spectra. Corrections that go beyond the Born-Oppenheimer approximation, including adiabatic, non-adiabatic, relativistic, and quantum electrodynamic corrections are becoming more feasible to calculate. As a result, experimental measurements performed on the H_3^+ ion serve as important benchmarks which are used to test the predictive power of new computational methods. By measuring many infrared transitions with precision at the sub-MHz level it is possible to construct a list of the most highly precise experimental rovibrational energy levels for this molecule. Until recently, only a select handful of infrared transitions of this molecule have been measured with high precision (˜ 1 MHz). Using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy, we are aiming to produce the largest high-precision spectroscopic dataset for this molecule to date. Presented here are the current results from our survey along with a discussion of the combination differences analysis used to extract the experimentally determined rovibrational energy levels. O. Polyansky, et al., Phil. Trans. R. Soc. A (2012), 370, 5014. M. Pavanello, et al., J. Chem. Phys. (2012), 136, 184303. L. Diniz, et al., Phys. Rev. A (2013), 88, 032506. L. Lodi, et al., Phys. Rev. A (2014), 89, 032505. J. Hodges, et al., J. Chem. Phys (2013), 139, 164201.

Quantitation of stable isotopic tracers of calcium by fast atom bombardment mass spectrometry

International Nuclear Information System (INIS)

Jiang, X.; Smith, D.L.

1987-01-01

Instrumentation and methodology developed for quantitation of stable isotopic traces in urine are described. Calcium is isolated from urine as the insoluble oxalate salt which is subsequently dissolved in hydrochloric acid. The isotopic content of the acid solution is determined by use of a conventional mass spectrometer equipped with a fast atom bombardment ion source. Calcium ions are desorbed from the sample surface by a beam of high-energy xenon atoms and detected with a high-resolution mass spectrometer. A data acquisition system has been developed to control the mass spectrometer and record the ion signals. Detailed analysis of potential sources of error indicates that the precision of the method is presently limited primarily by an isotope effect that occurs during ion desorption. Results presented here demonstrate that the relative abundances of calcium isotopes in urine can be determined with high precision (coefficient of variation < 0.2%) and that the method is a viable alternative to conventional thermal ionization mass spectrometry. The method is especially attractive because it uses a conventional high-resolution mass spectrometer which is routinely used for analysis of organic substances

Randomized quasi-Monte Carlo simulation of fast-ion thermalization

International Nuclear Information System (INIS)

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 2 14 . (paper)

A Real-Time Simulink Interfaced Fast-Charging Methodology of Lithium-Ion Batteries under Temperature Feedback with Fuzzy Logic Control

Directory of Open Access Journals (Sweden)

Muhammad Umair Ali

2018-05-01

Full Text Available The lithium-ion battery has high energy and power density, long life cycle, low toxicity, low discharge rate, more reliability, and better efficiency compared to other batteries. On the other hand, the issue of a reduction in charging time of the lithium-ion battery is still a bottleneck for the commercialization of electric vehicles (EVs. Therefore, an approach to charge lithium-ion batteries at a faster rate is needed. This paper proposes an efficient, real-time, fast-charging methodology of lithium-ion batteries. Fuzzy logic was adopted to drive the charging current trajectory. A temperature control unit was also implemented to evade the effects of fast charging on the aging mechanism. The proposed method of charging also protects the battery from overvoltage and overheating. Extensive testing and comprehensive analysis were conducted to examine the proposed charging technique. The results show that the proposed charging strategy favors a full battery recharging in 9.76% less time than the conventional constant-current–constant-voltage (CC/CV method. The strategy charges the battery at a 99.26% state of charge (SOC without significant degradation. The entire scheme was implemented in real time, using Arduino interfaced with MATLABTM Simulink. This decrease in charging time assists in the fast charging of cell phones and notebooks and in the large-scale deployment of EVs.

Profile measurements of localized fast electrons and ions in TORE SUPRA

International Nuclear Information System (INIS)

Basiuk, V.; Roubin, J.P.; Becoulet, A.; Carrasco, J.; Martin, G.; Moreau, D.; Saoutic, B.

1992-01-01

The strong toroidal and poloidal anisotropy of the heat flux to the first wall of Tore Supra during additional heating has been related to suprathermal particle losses induced by the TF ripple. In this paper we describe a new system of electric collectors designed to diagnose these localized particles and we analyse measurements performed during LHCD, ICRH and NBI heating. The interaction of fast particles created by additional heating with the TF ripple perturbation in Tore Supra has been analyzed by a direct measurement of the localized particles. The good confinement region has been identified thanks to a peak in the measured current profiles and is in agreement with theory. During LHCD and ICRH, the global losses are weak but strongly anisotropic leading to hot spots at the wall. During ICRH, an ejection of fast ions by the sawteeth towards peripheral zones where they get lost in the ripple has been seen. This is a possible scenario of α particle losses in a reactor

Analysis of resonant fast ion distributions during combined ICRF and NBI heating with transients using neutron emission spectroscopy

Science.gov (United States)

Hellesen, C.; Mantsinen, M.; Conroy, S.; Ericsson, G.; Eriksson, J.; Kiptily, V. G.; Nabais, F.; Contributors, JET

2018-05-01

ICRF heating at the fundamental cyclotron frequency of a hydrogen minority ion species also gives rise to a partial power absorption by deuterium ions at their second harmonic resonance. This paper studies the deuterium distributions resulting from such 2nd harmonic heating at JET using neutron emission spectroscopy data from the time of flight spectrometer TOFOR. The fast deuterium distributions are obtained over the energy range 100 keV to 2 MeV. Specifically, we study how the fast deuterium distributions vary as ICRF heating is used alone as well as in combination with NBI heating. When comparing the different heating scenarios, we observed both a difference in the shapes of the distributions as well as in their absolute level. The differences are most pronounced below 0.5 MeV. Comparisons are made with corresponding distributions calculated with the code PION. We find a good agreement between the measured distributions and those calculated with PION, both in terms of their shapes as well as their amplitudes. However, we also identified a period with signs of an inverted fast ion distribution, which showed large disagreements between the modeled and measured results. Resonant interactions with tornado modes, i.e. core localized toroidal alfven eigenmodes (TAEs), are put forward as a possible explanation for the inverted distribution.

The influence of the polarization and power of a photon target on the near-threshold detachment of fast H- ions

International Nuclear Information System (INIS)

Artemov, A.S.; Avidzba, A.A.; Vartazaryan, A.S.

1996-01-01

The results of theoretical investigation of the single- and two-photon detachment of fast negative hydrogen ions obtained in the framework of the zero-range-potential approximation at a photon energy above the single-photon threshold, are presented. The corresponding cross sections and near-threshold partial distributions of photoelectrons in the space of transverse momenta and energy of the laboratory frame are investigated in detail for various light-field polarization and the cross angles of ion and photon fluxes. For purposes of beam diagnostics the possibility of effective control of the fast H - ion photodetachment in a probing laser target is shown. Taking into account single-photon and background two-photon detachment channels the expressions, that allow one to obtain the resulting distributions of photoelectrons for various light power and photon energy in the near-threshold area of interest, are presented. Choosing the target power, the space orientation of the momentum and polarization of photons, one can realize the conditions of transfer of needed information about the beam to fast electrons of hydrogen atoms with a maximum accuracy. (author). 44 refs., 19 figs

Numerical simulations of fast ion loss measurements induced by magnetic islands in the ASDEX Upgrade tokamak

International Nuclear Information System (INIS)

Gobbin, M.; Marrelli, L.; Martin, P.; Fahrbach, H.U.; Garcia-Munoz, M.; Guenter, S.; White, R.B.

2009-01-01

A test particle approach, implemented with the Hamiltonian code ORBIT, is used to simulate measurements of fast ion losses induced by magnetic islands in the ASDEX Upgrade tokamak. In particular, the numerical simulations reproduce the toroidal localization of losses and the lost ions pitch angle and energy distribution experimentally measured with the fast ion losses detector (FILD) in the presence of a neoclassical tearing mode (NTM). The simulated NTM induced losses occurring on time scales longer than 100 μs are composed of mainly trapped or barely passing particles, consistently with the slow decay of the experimental signal from one FILD channel after the beam switch-off. The numerical simulations have been performed by taking into account the D-shaped plasma geometry, the collision mechanisms, the losses due to ripple effects and the rotation of the mode. The radial profile of the magnetic perturbation is adjusted in order to match ECE measurements. While statistical properties of FILD measurements are rather well reproduced, the simulated total amount of losses is found to be significantly affected by edge details of the magnetic perturbation as it determines the loss mechanism.

Numerical analyses on optimizing a heat pipe thermal management system for lithium-ion batteries during fast charging

International Nuclear Information System (INIS)

Ye, Yonghuang; Saw, Lip Huat; Shi, Yixiang; Tay, Andrew A.O.

2015-01-01

Thermal management is crucial for the operation of electric vehicles because lithium ion batteries are vulnerable to excessive heat generation during fast charging or other severe scenarios. In this work, an optimized heat pipe thermal management system (HPTMS) is proposed for fast charging lithium ion battery cell/pack. A numerical model is developed and comprehensively validated with experimental results. This model is then employed to investigate the thermal performance of the HPTMS under steady state and transient conditions. It is found that a cylinder vortex generator placed in front of the heat pipe condensers in the coolant stream improves the temperature uniformity. The uses of cooper heat spreaders and cooling fins greatly improve the performance of the thermal management system. Experiments and transient simulations of heat pipe thermal management system integrated with batteries prove that the improved HPTMS is capable for thermal management of batteries during fast charging. The air-cooled HPTMS is infeasible for thermal management of batteries during fast charging at the pack level due to the limitation of low specific heat capacity. - Highlights: • We develop a numerical model for optimizing a heat pipe thermal management system for fast charging batteries. • The numerical model is comprehensively validated with experimental data. • A cylinder vortex generator is placed at the inlet of the cooling stream to improve the temperature uniformity. • We validate the effectiveness of the optimized system with integration of prismatic batteries

Hybrid Donor-Dot Devices made using Top-down Ion Implantation for Quantum Computing

Science.gov (United States)

Bielejec, Edward; Bishop, Nathan; Carroll, Malcolm

2012-02-01

We present progress towards fabricating hybrid donor -- quantum dots (QD) for quantum computing. These devices will exploit the long coherence time of the donor system and the surface state manipulation associated with a QD. Fabrication requires detection of single ions implanted with 10's of nanometer precision. We show in this talk, 100% detection efficiency for single ions using a single ion Geiger mode avalanche (SIGMA) detector integrated into a Si MOS QD process flow. The NanoImplanter (nI) a focused ion beam system is used for precision top-down placement of the implanted ion. This machine has a 10 nm resolution combined with a mass velocity filter, allowing for the use of multi-species liquid metal ion sources (LMIS) to implant P and Sb ions, and a fast blanking and chopping system for single ion implants. The combination of the nI and integration of the SIGMA with the MOS QD process flow establishes a path to fabricate hybrid single donor-dot devices. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Enhanced Model for Fast Ignition

Energy Technology Data Exchange (ETDEWEB)

Mason, Rodney J. [Research Applications Corporation, Los Alamos, NM (United States)

2010-10-12

Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

The determination of cyanide in hydrometallurgical process solutions and effluents by ion chromatography

International Nuclear Information System (INIS)

Pohlandt, C.

1984-01-01

Three methods are described for the determination of cyanide species in hydrometallurgical process solutions and in effluents. The determination of excess cyanide in the presence of weak metal cyanide complexes was achieved by the use of a flow-injection system with 0,05mM sodium chloride as the carrier stream. The procedure was found to be fast, precise (S(sub r)0,0142), and reasonably accurate. Free cyanide and cyanide derived from weak metal cyanide complexes were determined by ion chromatography. This method is free from interferences and precise (s(sub r)0,0112), and has a limit of determination of 10μg0l. The 'total' cyanide content of solutions was determined by ion chromatography after the strong metal cyanide complexes had been dissociated in hypophosphorous acid by ultraviolet irradiation. The procedure (of 10 minutes duration) is faster than conventional distillation methods, and is accurate and precise (S(sub r)0,027)

COHERENT EVENTS AND SPECTRAL SHAPE AT ION KINETIC SCALES IN THE FAST SOLAR WIND TURBULENCE

Energy Technology Data Exchange (ETDEWEB)

Lion, Sonny; Alexandrova, Olga; Zaslavsky, Arnaud, E-mail: sonny.lion@obspm.fr [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité (France)

2016-06-10

In this paper we investigate spectral and phase coherence properties of magnetic fluctuations in the vicinity of the spectral transition from large, magnetohydrodynamic to sub-ion scales using in situ measurements of the Wind spacecraft in a fast stream. For the time interval investigated by Leamon et al. (1998) the phase coherence analysis shows the presence of sporadic quasi-parallel Alfvén ion cyclotron (AIC) waves as well as coherent structures in the form of large-amplitude, quasi-perpendicular Alfvén vortex-like structures and current sheets. These waves and structures importantly contribute to the observed power spectrum of magnetic fluctuations around ion scales; AIC waves contribute to the spectrum in a narrow frequency range whereas the coherent structures contribute to the spectrum over a wide frequency band from the inertial range to the sub-ion frequency range. We conclude that a particular combination of waves and coherent structures determines the spectral shape of the magnetic field spectrum around ion scales. This phenomenon provides a possible explanation for a high variability of the magnetic power spectra around ion scales observed in the solar wind.

COHERENT EVENTS AND SPECTRAL SHAPE AT ION KINETIC SCALES IN THE FAST SOLAR WIND TURBULENCE

International Nuclear Information System (INIS)

Lion, Sonny; Alexandrova, Olga; Zaslavsky, Arnaud

2016-01-01

In this paper we investigate spectral and phase coherence properties of magnetic fluctuations in the vicinity of the spectral transition from large, magnetohydrodynamic to sub-ion scales using in situ measurements of the Wind spacecraft in a fast stream. For the time interval investigated by Leamon et al. (1998) the phase coherence analysis shows the presence of sporadic quasi-parallel Alfvén ion cyclotron (AIC) waves as well as coherent structures in the form of large-amplitude, quasi-perpendicular Alfvén vortex-like structures and current sheets. These waves and structures importantly contribute to the observed power spectrum of magnetic fluctuations around ion scales; AIC waves contribute to the spectrum in a narrow frequency range whereas the coherent structures contribute to the spectrum over a wide frequency band from the inertial range to the sub-ion frequency range. We conclude that a particular combination of waves and coherent structures determines the spectral shape of the magnetic field spectrum around ion scales. This phenomenon provides a possible explanation for a high variability of the magnetic power spectra around ion scales observed in the solar wind.

Effects of toroidal field ripple on suprathermal ions in tokamak plasmas

International Nuclear Information System (INIS)

Goldston, R.J.; Towner, H.H.

1980-02-01

Analytic calculations of three important effects of toroidal field ripple on suprathermal ions in tokamak plasmas are presented. In the first process, collisional ripple-trapping, beam ions become trapped in local magnetic wells near their banana tips due to pitch-angle scattering as they traverse the ripple on barely unripple-trapped orbits. In the second process, collisionless ripple-trapping, near-perpendicular untrapped ions are captured (again near a banana tip) due to their finite orbits, which carry them out into regions of higher ripple. In the third process, banana-drift diffusion, fast-ion banana orbits fail to close precisely, due to a ripple-induced variable lingering period near the banana tips. These three mechanisms lead to substantial radial transport of banana-trapped, neutral-beam-injected ions when the quantity α* identical with epsilon/sin theta/Nqdelta is of order unity or smaller

Effects of toroidal field ripple on suprathermal ions in tokamak plasmas

International Nuclear Information System (INIS)

Goldston, R.J.; Towner, H.H.

1981-01-01

Analytic calculations of three important effects of toroidal field ripple on suprathermal ions in tokamak plasmas are presented. In the first process, collisional ripple-trapping, ions become trapped in local magnetic wells near their banana tips owing to pitch-angle scattering as they traverse the ripple on barely unripple-trapped orbits. In the second process, collisionless ripple-trapping, ions are captured (again near a banana tip) owing to their finite orbits, which carry them out into regions of higher ripple. In the third process, banana-drift diffusion, fast-ion banana orbits fail to close precisely, due to a ripple-induced 'variable lingering period' near the banana tips. These three mechanisms lead to substantial radial transport of banana-trapped, neutral-beam-injected ions when the quantity α* is identical with epsilonsinthetaNqdelta is of order unity or smaller. (author)

thermal, electrical and structural characterization of fast ion conducting glasses (Ag Br)x(AgPO)1-x

International Nuclear Information System (INIS)

Kartini, E.; Yufus, S.; Priyanto, T; Indayaningsih, N; Collins, M F

2001-01-01

Fast ion conducting glasses are of considerable technological interest because of their possible application in batteries, sensors, and displays. One of the main scientific challenges is to explain how the disordered structure of the glass is related to the high ionic conductivity that can be achieved at ambient temperature. Fast ion conducting glasses (AgBr) x (AgPO3) 1- x with x=0.0; 0.2; 0.3; 0.4; 0.5; 0.7; and 0.85 were prepared by rapid quenching. The studies of structure, thermal property and electrical conductivity have been made. The X-ray diffraction patterns of this system show that the sample are glasses for x 0.5. The neutron diffraction data shows that all AgBr doped glasses exhibit a strong and relatively sharp diffraction peak at anomalously low momentum transfer value, Q∼ 0.7 Α - 1. The low Q-peak is not observed in AgPO 3 glass, and in the X-ray data. The results of electrical conductivity show that the conduction is essentially ionic and due to silver ions alone. The logarithm of the ionic conductivity increases with increasing AgBr mole fraction, and reaches maximum for x = 0.5. The thermal property results measured by differential scanning calorimetric show that the temperatures of the glass transition, the crystallization and the melt reach minimum for the glass with composition x 0.5. We conclude that there appears to be a relation between higher conductivity at ambient temperature, and the low Q-peak. Based on this investigation a better fast ion conducting glass proposed is (AgBr) 0 .5(AgPO 3 ) 0 .5 with the conductivity of 8 x 10 - 5 S/cm

libstable: Fast, Parallel, and High-Precision Computation of α-Stable Distributions in R, C/C++, and MATLAB

Directory of Open Access Journals (Sweden)

Javier Royuela-del-Val

2017-06-01

Full Text Available α-stable distributions are a family of well-known probability distributions. However, the lack of closed analytical expressions hinders their application. Currently, several tools have been developed to numerically evaluate their density and distribution functions or to estimate their parameters, but available solutions either do not reach sufficient precision on their evaluations or are excessively slow for practical purposes. Moreover, they do not take full advantage of the parallel processing capabilities of current multi-core machines. Other solutions work only on a subset of the α-stable parameter space. In this paper we present an R package and a C/C++ library with a MATLAB front-end that permit parallelized, fast and high precision evaluation of density, distribution and quantile functions, as well as random variable generation and parameter estimation of α-stable distributions in their whole parameter space. The described library can be easily integrated into third party developments.

High Precision Beam Diagnostics for Ion Thrusters

NARCIS (Netherlands)

Van Reijen, B.; Koch, N.; Lazurenko, A.; Weis, S.; Schirra, M.; Genovese, A.; Haderspeck, J.; Gill, E.K.A.

2011-01-01

The Thales diagnostic equipment for ion beam characterization consists of a gridded and single orifice retarding potential analyzer (RPA) and an energy selective mass spectrometer (ESMS). During the development phase of these sensors considerable effort was put into the removal of ion optical

The practical model of electron emission in the radioisotope battery by fast ions

International Nuclear Information System (INIS)

Erokhine, N.S.; Balebanov, V.M.

2003-01-01

Under the theoretical analysis of secondary-emission radioisotope source of current the estimate of energy spectrum F(E) of secondary electrons with energy E emitted from films is the important problem. This characteristic knowledge allows, in particular, studying the volt-ampere function, the dependence of electric power deposited in the load on the system parameters and so on. Since the rigorous calculations of energy spectrum F(E) are the complicated enough and labour-intensive there is necessity to elaborate the practical model which allows by the simple computer routine on the basis of generalized data (both experimental measurements and theoretical calculations) on the stopping powers and mean free path of suprathermal electrons to perform reliable express-estimates of the energy spectrum F(E) and the volt-ampere function I(V) for the concrete materials of battery emitter films. This paper devoted to description of of the practical model to calculate electron emission characteristics under the passage of fast ion fluxes from the radioisotope source through the battery emitter. The analytical approximations for the stopping power of emitter materials, the electron inelastic mean free path, the ion production of fast electrons and the probability for them to arrive the film surface are taken into account. In the cases of copper and gold films, the secondary electron escaping depth, the position of energy spectrum peak are considered in the dependence on surface potential barrier magnitude U. According to our calculations the energy spectrum peak shifted to higher electron energy under the U growth. The model described may be used for express estimates and computer simulations of fast alpha-particles and suprathermal electrons interactions with the solid state plasma of battery emitter films, to study the electron emission layer characteristics including the secondary electron escaping depth, to find the optimum conditions for excitation of nonequilibrium

Development of a new measurement method for fast breeder reactor fuel burnup using a shielded ion microprobe analyzer

International Nuclear Information System (INIS)

Mizuno, M.; Enokido, Y.; Itaki, T.; Kono, K.; Unno, I.; Yamanouchi, S.

1985-01-01

A new method of burnup measurement using a shielded ion microprobe analyzer (SIMA) has been developed. The method is based on the isotope analysis of uranium, plutonium, and fission products in irradiated mixed oxide fuel by means of secondary ion mass spectrometry (SIMS). Fourteen samples irradiated in the Japanese experimental fast reactor JOYO were examined. The maximum local burnup of JOYO MK-I core fuels was about5.1 at. %. The axial burnup distribution of the fuel pin was in good agreement with that of the sibling pin in the same subassembly, measured by surface ionization mass spectrometry, which requires the chemical separation of fission products and heavy metals. The new method facilitates the rapid and accurate measurement of fast breeder reactor fuel burnup without human radiation exposure during sample preparation and analysis

Local magnetic shear control in a tokamak via fast wave minority ion current drive: Theory and experiments in JET

International Nuclear Information System (INIS)

Bhatnagar, V.P.; Start, D.F.H.; Jacquinot, J.; Chaland, F.; Cherubini, A.; Porcelli, F.

1994-01-01

When an ion cyclotron resonance heating (ICRH) antenna array is phased (Δ Φ ≠ 0 or π), the excited asymmetric k parallel spectrum can drive non-inductive currents by interaction of fast waves both with electrons (transit time magnetic pumping (e-TTMP) and Landau damping (e-LD)) and with ions at minority (fundamental) or harmonic cyclotron resonances, depending upon the scenario. On the basis of earlier theories, a simplified description is presented that includes the minority ion and electron current drive effects simultaneously in a 3-D ray tracing calculation in the tokamak geometry. The experimental results of sawtooth stabilization or destabilization in JET using the minority ion current drive scheme are presented. This scheme allows a modification of the local current density gradient (or the magnetic shear) at the q = 1 surface resulting in a control of a sawteeth. The predictions of the above model of current drive and its effects on sawtooth period calculated in conjunction with a model of stability of internal resistive kink modes, that encompasses the effects of both the fast particle pressure and the local (q = 1) magnetic shear, are found to be qualitatively in good agreement with the experimental results. Further, the results are discussed of our model of fast wave current drive scenarios of magnetic shear reversal with a view to achieving long duration high confinement regimes in the forthcoming experimental campaign on JET. Finally, the results are presented of minority current drive for sawtooth control in next step devices such as the International Thermonuclear Experimental Reactor (ITER). (author). 44 refs, 23 figs, 3 tabs

Complete momentum balance for single ionization of helium by fast ion impact: I. Experiment

Energy Technology Data Exchange (ETDEWEB)

Moshammer, R.; Kollmus, H.; Unverzagt, M.; Schmidt-Boecking, H. [Frankfurt Univ. (Germany). Inst. fuer Kernphysik; Ullrich, J.; Schmitt, W. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Wood, C.J.; Olson, R.E. [Missouri Univ., Rolla, MO (United States). Dept. of Physics

1997-02-01

The collision dynamics of He single ionization by 3.6 MeV/u Se{sup 28+} impact was explored using the GSI-reaction microscope, a high resolution integrated multi electron - recoil-ion momentum spectrometer. The complete three particle final state momentum distribution (9 cartesian components p{sub i}) was imaged with a resolution of {Delta}p{sub i} {approx} {+-}0.1 a.u. by measuring the three momentum components of the emitted electron and the recoiling target-ion in coincidence. The projectile energy loss has been determined on a level of {Delta}E{sub p}/E{sub p} {approx} 10{sup -7} and projectile scattering angles as small as {Delta}{theta} {approx} 10{sup -7}rad became accessible. The experimental data which are compared with results of classical trajectory Monte-Carlo (CTMC) calculations reveal an unprecedented insight into the details of the electron emission and the collision dynamics for ionization of helium by fast heavy-ion impact. (orig.)

Complete momentum balance for single ionization of helium by fast ion impact: I. Experiment

International Nuclear Information System (INIS)

Moshammer, R.; Kollmus, H.; Unverzagt, M.; Schmidt-Boecking, H.; Wood, C.J.; Olson, R.E.

1997-02-01

The collision dynamics of He single ionization by 3.6 MeV/u Se 28+ impact was explored using the GSI-reaction microscope, a high resolution integrated multi electron - recoil-ion momentum spectrometer. The complete three particle final state momentum distribution (9 cartesian components p i ) was imaged with a resolution of Δp i ∼ ±0.1 a.u. by measuring the three momentum components of the emitted electron and the recoiling target-ion in coincidence. The projectile energy loss has been determined on a level of ΔE p /E p ∼ 10 -7 and projectile scattering angles as small as Δθ ∼ 10 -7 rad became accessible. The experimental data which are compared with results of classical trajectory Monte-Carlo (CTMC) calculations reveal an unprecedented insight into the details of the electron emission and the collision dynamics for ionization of helium by fast heavy-ion impact. (orig.)

Self-consistent analysis of radial electric field and fast ion losses in CHS Torsatron/Heliotron

International Nuclear Information System (INIS)

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

1992-09-01

A self-consistent analysis is developed to determine the radial electric field and loss cone boundary in Torsatron/Heliotron plasmas under the influence of non-classical ion losses such as the loss cone loss ans charge exchange loss of fast ions with neutrals. Analysis is applied to the NBI heated plasmas in the Compact Helical System (CHS) device. Comparison is made between theoretical results and experimental observations. The increased ion particle losses caused by the orbit loss and charge exchange loss with neutrals make the radial electric field more negative than the value of purely neoclassical calculation. The partition of the injection energy among the shine through, direct orbit loss, change exchange loss and bulk heating is evaluated by using the self-consistent electric field profile. On-going experiments in the CHS device are briefly introduced. (author)

Importance of Ion Packing on the Dynamics of Ionic Liquids during Micropore Charging.

Science.gov (United States)

He, Yadong; Qiao, Rui; Vatamanu, Jenel; Borodin, Oleg; Bedrov, Dmitry; Huang, Jingsong; Sumpter, Bobby G

2016-01-07

Molecular simulations of the diffusion of EMIM(+) and TFSI(-) ions in slit-shaped micropores under conditions similar to those during charging show that in pores that accommodate only a single layer of ions, ions diffuse increasingly faster as the pore becomes charged (with diffusion coefficients even reaching ∼5 × 10(-9) m(2)/s), unless the pore becomes very highly charged. In pores wide enough to fit more than one layer of ions, ion diffusion is slower than in the bulk and changes modestly as the pore becomes charged. Analysis of these results revealed that the fast (or slow) diffusion of ions inside a micropore during charging is correlated most strongly with the dense (or loose) ion packing inside the pore. The molecular details of the ions and the precise width of the pores modify these trends weakly, except when the pore is so narrow that the ion conformation relaxation is strongly constrained by the pore walls.

Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector

Energy Technology Data Exchange (ETDEWEB)

Pace, D. C., E-mail: pacedc@fusion.gat.com; Fisher, R. K.; Van Zeeland, M. A. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Pipes, R. [Department of Physics, University of Hawaii, Hilo, Hawaii 96720-4091 (United States)

2014-11-15

New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector.

Science.gov (United States)

Pace, D C; Pipes, R; Fisher, R K; Van Zeeland, M A

2014-11-01

New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

Heat deposition on the first wall due to ICRF-induced loss of fast ions in JT-60U

International Nuclear Information System (INIS)

Kusama, Y.; Tobita, K.; Kimura, H.; Hamamatsu, K.; Fujii, T.; Nemoto, M.; Saigusa, M.; Moriyama, S.; Tani, K.; Koide, Y.; Sakasai, A.; Nishitani, T.; Ushigusa, K.

1995-01-01

In JT-60U, the heat deposition on the first wall due to the ICRF-induced loss of fast ions was investigated by changing the position of the resonance layer in the ripple-trapping region. A heat spot appears on the first wall of the same major radius as the resonance layer of the ICRF waves. The broadening of the heat spot in the major radius direction is consistent with that of the resonance layer due to the Doppler broadening. The heat spot is considered to be formed by the ICRF-induced ripple-trapped loss of fast ions. Although the total ICRF-induced loss power to the heat spot is as low as 2% of the total ICRF power, the additional heat flux will become a new issue because of the localized heat deposition on the first wall. ((orig.))

Charge states of fast heavy ions in solids; target atomic number dependence

International Nuclear Information System (INIS)

Shima, Kunihiro

1985-01-01

Discussions were carried out on the origin of Z 2 (atomic number) dependent charge states with respect to projectile electron loss and capture process, and on relationship between the Z 2 dependence and that of mean charge states for heavy ions of 1 MeV/u energy region. Present and previously reported results were examined on the equilibrium charge distributions, 9-bar, of 120 MeV 63 Cu, 25 and 40 MeV 35 Cl, 109 MeV Si and 59 MeV F ions. It was clarified that 9-bar became generally higher for lower Z 2 depending on increasing energy, and osillatory behavior with energy-depending amplitude was seen in 9-bar vs Z 2 . Discussions were carrid out on these phenomena and related matters. Z 2 oscillations of 9-bar of fast heavy ions might be due to those of electron capture cross section into projectile K and L vacancies for high and intermediate charge states, respectively. A quantitative interpretation of the Z 2 -dependent 9-bar values is in progress based on collision process and observation of projectile x-ray. The 9-bar value dependency on Z 2 in ion passing foils and decrease of Z 2 oscillation amplitude with increasing collision energy were quite similar to the Z 2 dependence in stopping powers or in effective charge states estimated from stopping powers. But there was some discrepancies in the Z 2 oscillation of 9-bar and that of stopping powers. (Takagi, S.)

Ions and electrons thermal effects on the fast-slow mode conversion process in a three components plasma

International Nuclear Information System (INIS)

Fidone, I.; Gomberoff, L.

1977-07-01

Fast-slow mode conversion in a deuterium plasma with a small amount of hydrogen impurity, for frequencies close to the two-ion hybrid frequency, is investigated. It is shown that while electron thermal effects tend to inhibit the wave conversion process, ion thermal effects tend to restore, qualitatively, the cold plasma properties, favouring therefore, the energy exchange between the two modes. The aforementioned effects are competitive for zetasub(o)sup(e)=1/nsub(parall).vsub(e)>=1. For zetasub(o)sup(e)<=1, electron thermal effects, in particular Landau damping, dominate over ion Larmor radius effects, drastically diminishing the wave conversion efficacy. For zetasub(o)sup(e)<<1, the coupling between the modes disappears altogether

Ultra high performance liquid chromatography with ion-trap TOF-MS for the fast characterization of flavonoids in Citrus bergamia juice.

Science.gov (United States)

Sommella, Eduardo; Pepe, Giacomo; Pagano, Francesco; Tenore, Gian Carlo; Dugo, Paola; Manfra, Michele; Campiglia, Pietro

2013-10-01

We have developed a fast ultra HPLC with ion-trap TOF-MS method for the analysis of flavonoids in Citrus bergamia juice. With respect to the typical methods for the analysis of these matrices based on conventional HPLC techniques, a tenfold faster separation was attained. The use of a core-shell particle column ensured high resolution within the fast analysis time of only 5 min. Unambiguous determination of flavonoid identity was obtained by the employment of a hybrid ion-trap TOF mass spectrometer with high mass accuracy (average error 1.69 ppm). The system showed good retention time and peak area repeatability, with maximum RSD% values of 0.36 and 3.86, respectively, as well as good linearity (R(2) ≥ 0.99). Our results show that ultra HPLC can be a useful tool for ultra fast qualitative/quantitative analysis of flavonoid compounds in citrus fruit juices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scintillator based detector for fast-ion losses induced by magnetohydrodynamic instabilities in the ASDEX upgrade tokamak.

Science.gov (United States)

García-Muñoz, M; Fahrbach, H-U; Zohm, H

2009-05-01

A scintillator based detector for fast-ion losses has been designed and installed on the ASDEX upgrade (AUG) tokamak [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)]. The detector resolves in time the energy and pitch angle of fast-ion losses induced by magnetohydrodynamics (MHD) fluctuations. The use of a novel scintillator material with a very short decay time and high quantum efficiency allows to identify the MHD fluctuations responsible for the ion losses through Fourier analysis. A Faraday cup (secondary scintillator plate) has been embedded behind the scintillator plate for an absolute calibration of the detector. The detector is mounted on a manipulator to vary its radial position with respect to the plasma. A thermocouple on the inner side of the graphite protection enables the safety search for the most adequate radial position. To align the scintillator light pattern with the light detectors a system composed by a lens and a vacuum-compatible halogen lamp has been allocated within the detector head. In this paper, the design of the scintillator probe, as well as the new technique used to analyze the data through spectrograms will be described. A last section is devoted to discuss the diagnosis prospects of this method for ITER [M. Shimada et al., Nucl. Fusion 47, S1 (2007)].

High-precision QED calculations of the hyperfine structure in hydrogen and transition rates in multicharged ions

Energy Technology Data Exchange (ETDEWEB)

Volotka, A.V.

2006-07-01

Studies of the hyperfine splitting in hydrogen are strongly motivated by the level of accuracy achieved in recent atomic physics experiments, which yield finally model-independent informations about nuclear structure parameters with utmost precision. Considering the current status of the determination of corrections to the hyperfine splitting of the ground state in hydrogen, this thesis provides further improved calculations by taking into account the most recent value for the proton charge radius. Comparing theoretical and experimental data of the hyperfine splitting in hydrogen the proton-size contribution is extracted and a relativistic formula for this contribution is derived in terms of moments of the nuclear charge and magnetization distributions. An iterative scheme for the determination of the Zemach and magnetic radii of the proton is proposed. As a result, the Zemach and magnetic radii are determined and the values are compared with the corresponding ones deduced from data obtained in electron-proton scattering experiments. The extraction of the Zemach radius from a rescaled difference between the hyperfine splitting in hydrogen and in muonium is considered as well. Investigations of forbidden radiative transitions in few-electron ions within ab initio QED provide a most sensitive tool for probing the influence of relativistic electron-correlation and QED corrections to the transition rates. Accordingly, a major part of this thesis is devoted to detailed studies of radiative and interelectronic-interaction effects to the transition probabilities. The renormalized expressions for the corresponding corrections in one- and twoelectron ions as well as for ions with one electron over closed shells are derived employing the two-time Green's function method. Numerical results for the correlation corrections to magnetic transition rates in He-like ions are presented. For the first time also the frequency-dependent contribution is calculated, which has to be

High-precision QED calculations of the hyperfine structure in hydrogen and transition rates in multicharged ions

International Nuclear Information System (INIS)

Volotka, A.V.

2006-01-01

Studies of the hyperfine splitting in hydrogen are strongly motivated by the level of accuracy achieved in recent atomic physics experiments, which yield finally model-independent informations about nuclear structure parameters with utmost precision. Considering the current status of the determination of corrections to the hyperfine splitting of the ground state in hydrogen, this thesis provides further improved calculations by taking into account the most recent value for the proton charge radius. Comparing theoretical and experimental data of the hyperfine splitting in hydrogen the proton-size contribution is extracted and a relativistic formula for this contribution is derived in terms of moments of the nuclear charge and magnetization distributions. An iterative scheme for the determination of the Zemach and magnetic radii of the proton is proposed. As a result, the Zemach and magnetic radii are determined and the values are compared with the corresponding ones deduced from data obtained in electron-proton scattering experiments. The extraction of the Zemach radius from a rescaled difference between the hyperfine splitting in hydrogen and in muonium is considered as well. Investigations of forbidden radiative transitions in few-electron ions within ab initio QED provide a most sensitive tool for probing the influence of relativistic electron-correlation and QED corrections to the transition rates. Accordingly, a major part of this thesis is devoted to detailed studies of radiative and interelectronic-interaction effects to the transition probabilities. The renormalized expressions for the corresponding corrections in one- and twoelectron ions as well as for ions with one electron over closed shells are derived employing the two-time Green's function method. Numerical results for the correlation corrections to magnetic transition rates in He-like ions are presented. For the first time also the frequency-dependent contribution is calculated, which has to be

High-resolution X-ray spectra from low-temperature, highly charged ions

International Nuclear Information System (INIS)

Beiersdorfer, P.

1996-09-01

The electron beam ion traps (EBIT) at Livermore were designed for studying the x-ray emission of highly charged ions produced and excited by a monoenergetic electron beam. The precision with which the x-ray emission can be analyzed has recently been increased markedly when it became possible to decouple the temperature of the ions from the energy of the electron beam by several orders of magnitude. By adjusting the trap parameters, ion temperatures as low as 15.8±4.4 eV for Ti 20+ and 59.4±9.9 eV for Cs 45+ were achieved. These temperatures were more than two orders of magnitude lower than the energy of the multi-keV electron beam used for the production and excitation of the ions. A discussion of the techniques used to produce and study low-temperature highly charged ions is presented in this progress report. The low ion temperatures enabled measurements heretofore impossible. As an example, a direct observation of the natural line width of fast electric dipole allowed x-ray transitions is described. From the observed natural line width and b making use of the time-energy relations of the uncertainty principle we were able to determine a radiative transition rate of 1.65 fs for the 2p-3d resonance transition in neonlike Cs 45+ . A brief discussion of other high-precision measurements enabled by our new technique is also given

Precision Measurement of the Electron's Electric Dipole Moment Using Trapped Molecular Ions

Science.gov (United States)

Cairncross, William B.; Gresh, Daniel N.; Grau, Matt; Cossel, Kevin C.; Roussy, Tanya S.; Ni, Yiqi; Zhou, Yan; Ye, Jun; Cornell, Eric A.

2017-10-01

We describe the first precision measurement of the electron's electric dipole moment (de) using trapped molecular ions, demonstrating the application of spin interrogation times over 700 ms to achieve high sensitivity and stringent rejection of systematic errors. Through electron spin resonance spectroscopy on 180Hf 19F+ in its metastable 3Δ1 electronic state, we obtain de=(0.9 ±7. 7stat±1. 7syst)×10-29 e cm , resulting in an upper bound of |de|<1.3 ×10-28 e cm (90% confidence). Our result provides independent confirmation of the current upper bound of |de|<9.4 ×10-29 e cm [J. Baron et al., New J. Phys. 19, 073029 (2017), 10.1088/1367-2630/aa708e], and offers the potential to improve on this limit in the near future.

Charging of insulators by multiply-charged-ion impact probed by slowing down of fast binary-encounter electrons

Science.gov (United States)

de Filippo, E.; Lanzanó, G.; Amorini, F.; Cardella, G.; Geraci, E.; Grassi, L.; La Guidara, E.; Lombardo, I.; Politi, G.; Rizzo, F.; Russotto, P.; Volant, C.; Hagmann, S.; Rothard, H.

2010-12-01

The interaction of ion beams with insulators leads to charging-up phenomena, which at present are under investigation in connection with guiding phenomena in nanocapillaries with possible application in nanofocused beams. We studied the charging dynamics of insulating foil targets [Mylar, polypropylene (PP)] irradiated with swift ion beams (C, O, Ag, and Xe at 40, 23, 40, and 30 MeV/u, respectively) via the measurement of the slowing down of fast binary-encounter electrons. Also, sandwich targets (Mylar covered with a thin Au layer on both surfaces) and Mylar with Au on only one surface were used. Fast-electron spectra were measured by the time-of-flight method at the superconducting cyclotron of Laboratori Nazionali del Sud (LNS) Catania. The charge buildup leads to target-material-dependent potentials of the order of 6.0 kV for Mylar and 2.8 kV for PP. The sandwich targets, surprisingly, show the same behavior as the insulating targets, whereas a single Au layer on the electron and ion exit side strongly suppresses the charging phenomenon. The accumulated number of projectiles needed for charging up is inversely proportional to electronic energy loss. Thus, the charging up is directly related to emission of secondary electrons.

Charging of insulators by multiply-charged-ion impact probed by slowing down of fast binary-encounter electrons

International Nuclear Information System (INIS)

De Filippo, E.; Lanzano, G.; Cardella, G.; Amorini, F.; Geraci, E.; Grassi, L.; Politi, G.; La Guidara, E.; Lombardo, I.; Rizzo, F.; Russotto, P.; Volant, C.; Hagmann, S.; Rothard, H.

2010-01-01

The interaction of ion beams with insulators leads to charging-up phenomena, which at present are under investigation in connection with guiding phenomena in nanocapillaries with possible application in nanofocused beams. We studied the charging dynamics of insulating foil targets [Mylar, polypropylene (PP)] irradiated with swift ion beams (C, O, Ag, and Xe at 40, 23, 40, and 30 MeV/u, respectively) via the measurement of the slowing down of fast binary-encounter electrons. Also, sandwich targets (Mylar covered with a thin Au layer on both surfaces) and Mylar with Au on only one surface were used. Fast-electron spectra were measured by the time-of-flight method at the superconducting cyclotron of Laboratori Nazionali del Sud (LNS) Catania. The charge buildup leads to target-material-dependent potentials of the order of 6.0 kV for Mylar and 2.8 kV for PP. The sandwich targets, surprisingly, show the same behavior as the insulating targets, whereas a single Au layer on the electron and ion exit side strongly suppresses the charging phenomenon. The accumulated number of projectiles needed for charging up is inversely proportional to electronic energy loss. Thus, the charging up is directly related to emission of secondary electrons.

Innershell ionization by fast protons, alpha particles and carbon ions

International Nuclear Information System (INIS)

Dijk, J.H. van.

1984-01-01

The subject of this thesis is the study of inner-shell excitations of atoms induced by fast charged particle collisions. A new method is described for measuring the spectrum of delta-electrons emitted by 208 Pb after excitation by 15 MeV protons or 50 MeV alpha particles. Experimental equipment is described. Results of both experiments are presented and compared with PWBA models and with calculations based on a semi-classical approximation. The small-impact-parameter ionization probabilities obtained are then compared with literature. Also small-impact-parameter measurements done with 100 MeV carbon ions are described. Besides K-shell measurements, the author also presents L-subshell ionization probability results for Pb. An appendix is added in which energy straggling problems in solid targets are treated. (Auth./G.J.P.)

Effect of the nuclear charge of a fast structural ion on its internal effective stopping in collisions with atoms

Energy Technology Data Exchange (ETDEWEB)

Gusarevich, E. S., E-mail: gusarevich@gmail.com [Lomonosov Nothern (Arctic) Federal University (Russian Federation)

2017-02-15

The energy losses of fast structural ions in collisions with atoms have been considered in the eikonal approximation. The structural ions are ions consisting of a nucleus and a certain number of electrons bound to it. The effect of nuclear charge Z of the ion on its effective deceleration κ{sup (p)} (energy losses associated with excitation of only intrinsic ion shells) has been analyzed. It is shown that the allowance for the interaction of an atom with the ion nucleus for Z{sub a}Z/v > 1, where Z{sub a} is the charge of the atomic nucleus and v is the velocity of collisions in atomic units, considerably affects the value of κ{sup (p)}, which generally necessitates taking into account nonperturbatively the effect of both charges Z{sub a} and Z on κ{sup (p)}.

Analytical and Numerical Studies of the Complex Interaction of a Fast Ion Beam Pulse with a Background Plasma

International Nuclear Information System (INIS)

Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.

2003-01-01

Plasma neutralization of an intense ion beam pulse is of interest for many applications, including plasma lenses, heavy ion fusion, high energy physics, etc. Comprehensive analytical, numerical, and experimental studies are underway to investigate the complex interaction of a fast ion beam with a background plasma. The positively charged ion beam attracts plasma electrons, and as a result the plasma electrons have a tendency to neutralize the beam charge and current. A suite of particle-in-cell codes has been developed to study the propagation of an ion beam pulse through the background plasma. For quasi-steady-state propagation of the ion beam pulse, an analytical theory has been developed using the assumption of long charge bunches and conservation of generalized vorticity. The analytical results agree well with the results of the numerical simulations. The visualization of the data obtained in the numerical simulations shows complex collective phenomena during beam entry into and ex it from the plasma

Quantum treatment of the capture of an atom by a fast nucleus incident on a molecule

International Nuclear Information System (INIS)

Shakeshaft, R.; Spruch, L.

1980-01-01

The classical double-scattering model of Thomas for the capture of electrons from atoms by fast ions yields a cross section sigma which dominates over the single scattering contribution for sufficiently fast ions. The magnitude of the classical double-scattering sigma differs, however, from its quantum-mechanical (second-Born) analog by an order of magnitude. Further, a ''fast ion'' means an ion of some MeV, and at those energies the cross sections are very low. On the other hand, as noted by Bates, Cook, and Smith, the double-scattering cross section for the capture of atoms from molecules by fast ions dominates over the single-scattering contribution for incident ions of very much lower energy; roughly, one must have the velocity of the incident projectile much larger than a characteristic internal velocity of the particles in the target. It follows that we are in the asymptotic domain not at about 10 MeV but at about 100 eV. For the reaction H + +CH 4 → H 2 + +CH 3 with incident proton energies of 70 to 150 eV, the peak in the angular distribution as determined experimentally is at almost precisely the value predicted by the classical model, but the theoretical total cross section is about 30 times too large. Using a quantum version of the classical model, which involves the same kinematics and therefore preserves the agreement with the angular distribution, we obtain somewhat better agreement with the experimental total cross section, by a factor of about 5. In the center-of-mass frame, for sufficiently high incident energy, the first of the two scatterings involves the scattering of H + by H through an angle of very close to 90 0 , and it follows that the nuclei of the emergent H 2 + ion will almost all be in the singlet state. We have also calculated the cross section for the reaction D + +CH 4 → (HD) + +CH 3

BOKASUN: A fast and precise numerical program to calculate the Master Integrals of the two-loop sunrise diagrams

Science.gov (United States)

Caffo, Michele; Czyż, Henryk; Gunia, Michał; Remiddi, Ettore

2009-03-01

We present the program BOKASUN for fast and precise evaluation of the Master Integrals of the two-loop self-mass sunrise diagram for arbitrary values of the internal masses and the external four-momentum. We use a combination of two methods: a Bernoulli accelerated series expansion and a Runge-Kutta numerical solution of a system of linear differential equations. Program summaryProgram title: BOKASUN Catalogue identifier: AECG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 9404 No. of bytes in distributed program, including test data, etc.: 104 123 Distribution format: tar.gz Programming language: FORTRAN77 Computer: Any computer with a Fortran compiler accepting FORTRAN77 standard. Tested on various PC's with LINUX Operating system: LINUX RAM: 120 kbytes Classification: 4.4 Nature of problem: Any integral arising in the evaluation of the two-loop sunrise Feynman diagram can be expressed in terms of a given set of Master Integrals, which should be calculated numerically. The program provides a fast and precise evaluation method of the Master Integrals for arbitrary (but not vanishing) masses and arbitrary value of the external momentum. Solution method: The integrals depend on three internal masses and the external momentum squared p. The method is a combination of an accelerated expansion in 1/p in its (pretty large!) region of fast convergence and of a Runge-Kutta numerical solution of a system of linear differential equations. Running time: To obtain 4 Master Integrals on PC with 2 GHz processor it takes 3 μs for series expansion with pre-calculated coefficients, 80 μs for series expansion without pre-calculated coefficients, from a few seconds up to a few minutes for Runge-Kutta method (depending

Deterministic ion beam material adding technology for high-precision optical surfaces.

Science.gov (United States)

Liao, Wenlin; Dai, Yifan; Xie, Xuhui; Zhou, Lin

2013-02-20

Although ion beam figuring (IBF) provides a highly deterministic method for the precision figuring of optical components, several problems still need to be addressed, such as the limited correcting capability for mid-to-high spatial frequency surface errors and low machining efficiency for pit defects on surfaces. We propose a figuring method named deterministic ion beam material adding (IBA) technology to solve those problems in IBF. The current deterministic optical figuring mechanism, which is dedicated to removing local protuberances on optical surfaces, is enriched and developed by the IBA technology. Compared with IBF, this method can realize the uniform convergence of surface errors, where the particle transferring effect generated in the IBA process can effectively correct the mid-to-high spatial frequency errors. In addition, IBA can rapidly correct the pit defects on the surface and greatly improve the machining efficiency of the figuring process. The verification experiments are accomplished on our experimental installation to validate the feasibility of the IBA method. First, a fused silica sample with a rectangular pit defect is figured by using IBA. Through two iterations within only 47.5 min, this highly steep pit is effectively corrected, and the surface error is improved from the original 24.69 nm root mean square (RMS) to the final 3.68 nm RMS. Then another experiment is carried out to demonstrate the correcting capability of IBA for mid-to-high spatial frequency surface errors, and the final results indicate that the surface accuracy and surface quality can be simultaneously improved.

A self-calibrating ionisation chamber for the precise intensity calibration of high-energy heavy-ion beam monitors

International Nuclear Information System (INIS)

Junghans, A.

1996-01-01

The intensity of a 136 Xe(600 A MeV) beam has been determined by simultaneously measuring the particle rate and the corresponding ionisation current with an ionisation chamber. The ionisation current of this self-calibrating device was compared at higher intensities with the current of a secondary-electron monitor and a calibration of the secondary-electron current was achieved with a precision of 2%. This method can be applied to all high-energy heavy-ion beams. (orig.)

Energy measurement of fast ions trapped in the toroidal magnetic field ripple of Tore Supra during ICRF heating

International Nuclear Information System (INIS)

Basiuk, V.; Becoulet, A.; Grisolia, C.; Hutter, T.; Mayaux, G.; Martin, G.; Saoutic, B.; Vartanian, S.

1995-01-01

Direct losses of ions trapped in the toroidal field ripple of Tore Supra using two techniques were made. The first (DRIPPLE I) correlates the ion loss current measured by an electric probe with the ion loss power measured by a calorimeter. As the calorimeter integrates over all particle energies and time, it yields only the averaged lost ion energy. The second technique (DRIPPLE II), still under development, is a Faraday cup positioned and filtered so as to select ions by their Larmor radius. The currents measured are small (1-100 nA), and improvements in instrumentation are needed to take full advantage of the data, but the preliminary results are still useful. During ICRH (hydrogen minority regime, resonance on axis) a direct correlation between the lost ion mean energy and the density of hydrogen was seen. The energy increased when the hydrogen minority density decreased. Moreover, the line averaged density and the lower hybrid heating (LH) had also an effect on fast ion losses. (authors). 3 refs., 7 figs

Fast wave heating of two-ion plasmas in the Princeton large torus through minority cyclotron resonance damping

International Nuclear Information System (INIS)

Hosea, J.; Bernabei, S.; Colestock, P.

1979-07-01

Strong minority proton heating is produced in PLT through ion cyclotron resonance damping of fast waves at moderate rf power levels. In addition to demonstrating good proton confinement, the proton energy distribution is consistent with Fokker--Planck theory which provides the prescription for extrapolation of this heating regime to higher rf power levels

MONDO: A tracker for the characterization of secondary fast and ultrafast neutrons emitted in particle therapy

Science.gov (United States)

Mirabelli, R.; Battistoni, G.; Giacometti, V.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Traini, G.; Marafini, M.

2018-01-01

In Particle Therapy (PT) accelerated charged particles and light ions are used for treating tumors. One of the main limitation to the precision of PT is the emission of secondary particles due to the beam interaction with the patient: secondary emitted neutrons can release a significant dose far from the tumor. Therefore, a precise characterization of their flux, production energy and angle distribution is eagerly needed in order to improve the Treatment Planning Systems (TPS) codes. The principal aim of the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project is the development of a tracking device optimized for the detection of fast and ultra-fast secondary neutrons emitted in PT. The detector consists of a matrix of scintillating square fibres coupled with a CMOS-based readout. Here, we present the characterization of the detector tracker prototype and CMOS-based digital SPAD (Single Photon Avalanche Diode) array sensor tested with protons at the Beam Test Facility (Frascati, Italy) and at the Proton Therapy Centre (Trento, Italy), respectively.

The description of charge transfer in fast negative ions scattering on water covered Si(100) surfaces

Energy Technology Data Exchange (ETDEWEB)

Chen, Lin; Qiu, Shunli; Liu, Pinyang; Xiong, Feifei; Lu, Jianjie; Liu, Yuefeng; Li, Guopeng; Liu, Yiran; Ren, Fei; Xiao, Yunqing; Gao, Lei; Zhao, Qiushuang; Ding, Bin; Li, Yuan [School of Nuclear Science and Technology, Lanzhou University, 730000 (China); Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000 (China); Guo, Yanling, E-mail: guoyanling@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, 730000 (China); Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000 (China); Chen, Ximeng, E-mail: chenxm@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, 730000 (China); Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000 (China)

2016-11-30

Highlights: • We first observe that negative-ion fractions present no variation with the doping concentration, which is very different from the results of low energy Li neutralization from doped Si samples. • Our work shows that the affinity levels and collision time significantly counteract the band gap effect on negative ion formation. The work will improve our understanding on electron transfer on semiconductor surfaces associated with doping. • In addition, we build a complete theoretical framework to quantitatively calculate the negative-ion fractions. • Our work is related to charge transfer on semiconductor surfaces, which will be of interest to a broad audience due to the wide necessity of the knowledge of charge exchange on semiconductor surfaces in different fields. - Abstract: Doping has significantly affected the characteristics and performance of semiconductor electronic devices. In this work, we study the charge transfer processes for 8.5–22.5 keV C{sup −} and F{sup −} ions scattering on H{sub 2}O-terminated p-type Si(100) surfaces with two different doping concentrations. We find that doping has no influence on negative-ion formation for fast collisions in this relatively high energy range. Moreover, we build a model to calculate negative ion fractions including the contribution from positive ions. The calculations support the nonadiabatic feature of charge transfer.

Contribution to the study of sputtering and damage of uranium dioxide by fast heavy ions

International Nuclear Information System (INIS)

Schlutig, S.

2001-03-01

Swift heavy ion-solid interaction leads in volume to track creation and on the surface to the ejection of particles into the vacuum. To learn more about initial mechanisms of track formation, we are focused on the sputtering of uranium dioxide by fast heavy ions. This present study is exclusively devoted to the influence of the electronic stopping power on the emission of neutral particles and especially on their angular distribution. These measurements are completed by those of the ions emitted from UO 2 targets bombarded with swift heavy ions. The whole experimental results give access to: i) the nature of the sputtered particles; ii) the charge state of the emitted particles; iii) the direction of ejection of the sputtered particles ; iv) the sputtering yields deduced from the angular distributions. These results are compared to the prediction of the sputtering models proposed in the literature and it seems that the supersonic gas flow model is well suited to describe our results. Finally, the sputtering yields are compared with a set of earlier experimental data on uranium dioxide damage obtained by T. Wiss and we observe that only a small fraction of UO 2 monolayers are sputtered. (author)

Light ions cyclotron bombardment to simulate fast neutron radiation damage in nuclear materials

International Nuclear Information System (INIS)

Segura, E.; Lucki, G.; Aguiar, D.

1984-01-01

The applicability and limitations of the use of cyclotron light ions bombardment to simulate the effects of the neutron irradiation are presented. Light ions with energies of about 10 MeV are capable to produce homogeneous damage in specimens suitable for measuring bulk mechanical properties although their low damage rate of 10 -5 dpa.sec -1 limit the dose range to a few dpa. On the other hand, cyclotron alpha particle implantation provides a fast and convenient way of introducing helium with a minimum of side effects so that we can take advantage of this technique to get better understanding of the mechanism by which this insoluble gas produces high temperature embrittlement. Some experimental details such as dimensions and cooling techniques are described. Finally a description of the infrastructure for cyclotron alpha particle implantation and a creep-test facility of the Division of Radiation Damage at IPEN-CNEN/SP are presented. (Author) [pt

Sensitivity Analysis of Deviation Source for Fast Assembly Precision Optimization

Directory of Open Access Journals (Sweden)

Jianjun Tang

2014-01-01

Full Text Available Assembly precision optimization of complex product has a huge benefit in improving the quality of our products. Due to the impact of a variety of deviation source coupling phenomena, the goal of assembly precision optimization is difficult to be confirmed accurately. In order to achieve optimization of assembly precision accurately and rapidly, sensitivity analysis of deviation source is proposed. First, deviation source sensitivity is defined as the ratio of assembly dimension variation and deviation source dimension variation. Second, according to assembly constraint relations, assembly sequences and locating, deviation transmission paths are established by locating the joints between the adjacent parts, and establishing each part’s datum reference frame. Third, assembly multidimensional vector loops are created using deviation transmission paths, and the corresponding scalar equations of each dimension are established. Then, assembly deviation source sensitivity is calculated by using a first-order Taylor expansion and matrix transformation method. Finally, taking assembly precision optimization of wing flap rocker as an example, the effectiveness and efficiency of the deviation source sensitivity analysis method are verified.

Ion cyclotron emission by spontaneous emission

Energy Technology Data Exchange (ETDEWEB)

Da Costa, O [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Gresillon, D [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises

1994-07-01

The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs.

Ion cyclotron emission by spontaneous emission

International Nuclear Information System (INIS)

Da Costa, O.; Gresillon, D.

1994-01-01

The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs

A Thomson scattering diagnostic to measure fast ion and α-particle distributions in JET

International Nuclear Information System (INIS)

Costley, A.E.; Hoekzema, J.A.; Stott, P.E.; Watkins, M.L.

1988-01-01

The paper presents the findings of a feasibility investigation into the proposed Thomson scattering diagnostic to measure fast ion and α-particle distributions in JET. A description is given of the motivation for alpha particle diagnostics on JET, followed by a brief survey of possible α-particle diagnostics for JET. The basic principles of the collective Thomson scattering technique are presented, along with its implementation on JET. The expected performance of the system, and other applications of the diagnostic system are also discussed. (U.K.)

LASL lens design procedure: simple, fast, precise, versatile

International Nuclear Information System (INIS)

Brixner, B.

1978-11-01

The Los Alamos Scientific Laboratory general-purpose lens design procedure optimizes specific lens prescriptions to obtain the smallest possible image spots and therefore near-spherical wave fronts of light converging on all images in the field of view. Optical image errors are analyzed in much the same way that they are measured on the optical bench. This lens design method is made possible by using the full capabilities of large electronic computers. First, the performance of the whole lens is sampled with many precisely traced skew rays. Next, lens performance is analyzed with spot diagrams generated by the many rays. Third, lens performance is optimized with a least squares system aimed at reducing all image errors to zero. This statistical approach to lens design uses skew rays and precisely measured ray deviations from ideal image points to achieve greater accuracy than was possible with the classical procedure, which is based on approximate expressions derived from simplified ray traces developed for pencil-and-paper calculations

Power supply system for negative ion source at IPR

Science.gov (United States)

Gahlaut, Agrajit; Sonara, Jashwant; Parmar, K. G.; Soni, Jignesh; Bandyopadhyay, M.; Singh, Mahendrajit; Bansal, Gourab; Pandya, Kaushal; Chakraborty, Arun

2010-02-01

The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly - RF based, where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ~5 × 1012 cm-3, from which ~ 10 A of negative ion beam shall be produced and accelerated to 35 kV, through an electrostatic ion accelerator. The experimental system is modelled similar to the RF based negative ion source, BATMAN presently operating at IPP, Garching, Germany. The mechanical system for Negative Ion Source Assembly is close to the IPP source, remaining systems are designed and procured principally from indigenous sources, keeping the IPP configuration as a base line. High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup. The HV power supplies for extraction and acceleration are rated for high voltage (~15 to 35kV), and high current (~ 15 to 35A). Other attributes are, fast rate of voltage rise (< 5ms), good regulation (< ±1%), low ripple (< ±2%), isolation (~50kV), low energy content (< 10J) and fast cut-off (< 100μs). The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids; have attributes of low ripple, high stability, fast and precise regulation, programmability and remote operation. These power supplies are also equipped with over-voltage, over-current and current limit (CC Mode) protections. Fault diagnostics, to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme. To restrict the fault energy deposited on the ion source, specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy. Moreover, the monitoring status and control signals from these power supplies are required to be electrically (~ 50kV) isolated from the system. The paper shall present the

Power supply system for negative ion source at IPR

International Nuclear Information System (INIS)

Gahlaut, Agrajit; Sonara, Jashwant; Parmar, K G; Soni, Jignesh; Bandyopadhyay, M; Singh, Mahendrajit; Bansal, Gourab; Pandya, Kaushal; Chakraborty, Arun

2010-01-01

The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly - RF based, where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ∼5 x 10 12 cm -3 , from which ∼ 10 A of negative ion beam shall be produced and accelerated to 35 kV, through an electrostatic ion accelerator. The experimental system is modelled similar to the RF based negative ion source, BATMAN presently operating at IPP, Garching, Germany. The mechanical system for Negative Ion Source Assembly is close to the IPP source, remaining systems are designed and procured principally from indigenous sources, keeping the IPP configuration as a base line. High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup. The HV power supplies for extraction and acceleration are rated for high voltage (∼15 to 35kV), and high current (∼ 15 to 35A). Other attributes are, fast rate of voltage rise (< 5ms), good regulation (< ±1%), low ripple (< ±2%), isolation (∼50kV), low energy content (< 10J) and fast cut-off (< 100μs). The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids; have attributes of low ripple, high stability, fast and precise regulation, programmability and remote operation. These power supplies are also equipped with over-voltage, over-current and current limit (CC Mode) protections. Fault diagnostics, to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme. To restrict the fault energy deposited on the ion source, specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy. Moreover, the monitoring status and control signals from these power supplies are required to be electrically (∼ 50kV) isolated from the system. The paper shall

Effect of thermal contact resistances on fast charging of large format lithium ion batteries

International Nuclear Information System (INIS)

Ye, Yonghuang; Saw, Lip Huat; Shi, Yixiang; Somasundaram, Karthik; Tay, Andrew A.O.

2014-01-01

Highlights: • The effect of thermal contact resistance on thermal performance of large format lithium ion batteries. • The effect of temperature gradient on electrochemical performance of large format batteries during fast charging. • The thermal performance of lithium ion battery utilizing pulse charging protocol. • Suggestions on battery geometry design optimization to improve thermal performance. - Abstract: A two dimensional electrochemical thermal model is developed on the cross-plane of a laminate stack plate pouch lithium ion battery to study the thermal performance of large format batteries. The effect of thermal contact resistance is taken into consideration, and is found to greatly increase the maximum temperature and temperature gradient of the battery. The resulting large temperature gradient would induce in-cell non-uniformity of charging-discharging current and state of health. Simply increasing the cooling intensity is inadequate to reduce the maximum temperature and narrow down the temperature difference due to the poor cross-plane thermal conductivity. Pulse charging protocol does not help to mitigate the temperature difference on the bias of same total charging time, because of larger time-averaged heat generation rate than constant current charging. Suggestions on battery geometry optimizations for both prismatic/pouch battery and cylindrical battery are proposed to reduce the maximum temperature and mitigate the temperature gradient within the lithium ion battery

Use of positive ion fast atom bombardment mass spectrometry for rapid identification of a bile alcohol glucuronide isolated from cerebrotendinous xanthomatosis patients

International Nuclear Information System (INIS)

Dayal, B.; Salen, G.; Tint, G.S.; Shefer, S.; Benz, S.W.

1990-01-01

The identification of a major biliary and plasma bile alcohol glucuronide, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol-3-0-beta-D-glucuronide, present in cerebrotendinous xanthomatosis (CTX) patients, was investigated by positive ion fast atom bombardment mass spectrometry (FAB-MS). The spectrum was characterized by abundant ions formed by attachment of a proton, [M + H]+, or of alkali ions, [M + Na]+ and [M + 39K]+, to the glucuronide salt. These ions allowed an unambiguous deduction of the molecular weight of the sample. It is suggested that FAB-MS could be used in the rapid diagnosis of CTX

Fast ion power loads on ITER first wall structures in the presence of NTMs and microturbulence

International Nuclear Information System (INIS)

Kurki-Suonio, T.; Asunta, O.; Hirvijoki, E.; Koskela, T.; Snicker, A.; Sipilae, S.; Hauff, T.; Jenko, F.; Poli, E.

2011-01-01

The level and distribution of the wall power flux of energetic ions in ITER have to be known accurately in order to ensure the integrity of the first wall. Until now, most quantitative estimates have been based on the assumption that fast ion transport is dictated by neoclassical effects only. However, in ITER, the fast ion distribution is likely to be affected by various MHD effects and probably also by microturbulence. We have now upgraded our orbit-following Monte Carlo code ASCOT so that it has simple, theory-based models for neoclassical tearing mode (NTM)-type islands as well as for turbulent diffusion. ASCOT also allows for full-orbit following, which is important close to the material surfaces and, possibly, also when strong toroidal inhomogeneities are present in the magnetic field. Here we introduce the new models, preliminary results obtained with them, and how these models could be made more realistic in the future. The simulations are carried out for thermonuclear alpha particles in ITER scenario 2 plasma, because we consider this combination to be most critical for the successful operation of ITER. Neither the turbulent transport nor NTM-type islands are found to introduce alarming changes in the wall loads. However, at this stage it was not possible to combine the island structures with the non-axisymmetric magnetic field of ITER, and it remains to be seen what the combined effect of drift islands together with the toroidal ripple and local field aberrations, such as those due to test blanket modules and resonant magnetic perturbations will be.

Ion beam nanopatterning and micro-Raman spectroscopy analysis on HOPG for testing FIB performances

International Nuclear Information System (INIS)

Archanjo, B.S.; Maciel, I.O.; Martins Ferreira, E.H.; Peripolli, S.B.; Damasceno, J.C.; Achete, C.A.; Jorio, A.

2011-01-01

This work reports Ga + focused ion beam nanopatterning to create amorphous defects with periodic square arrays in highly oriented pyrolytic graphite and the use of Raman spectroscopy as a new protocol to test and compare progresses in ion beam optics, for low fluence bombardment or fast writing speed. This can be ultimately used as a metrological tool for comparing different FIB machines and can contribute to Focused Ion Beam (FIB) development in general for tailoring nanostructures with higher precision. In order to do that, the amount of ion at each spot was varied from about 10 6 down to roughly 1 ion per dot. These defects were also analyzed by using high resolution scanning electron microscopy and atomic force microscopy. The sensitivities of these techniques were compared and a geometrical model is proposed for micro-Raman spectroscopy in which the intensity of the defect induced D band, for a fixed ion dose, is associated with the diameter of the ion beam. In addition, the lateral increase in the bombarded spot due to the cascade effect of the ions on graphite surface was extracted from this model. A semi-quantitative analysis of the distribution of ions at low doses per dot or high writing speed for soft modification of materials is discussed. -- Highlights: → Highly oriented pyrolytic graphite surface is bombarded using a focused ion beam. → Raman spectroscopy is used to propose a new protocol to test focused ion beam optics. → Scattering diameter of the ions on HOPG surface is experimentally obtained. → Optical limitations of the ion column in fast writing speed are discussed. → Small level of modifications is considered for changing graphene conductive properties.

Methodology for nuclear magnetic resonance and ion cyclotron resonance mass spectrometry

International Nuclear Information System (INIS)

Sehgal, Akansha

2014-01-01

This thesis encompasses methodological developments in both nuclear magnetic resonance and Fourier transform ion cyclotron resonance mass spectrometry. The NMR section explores the effects of scalar relaxation on a coupled nucleus to measure fast exchange rates. In order to quantify these rates accurately, a precise knowledge of the chemical shifts of the labile protons and of the scalar couplings is normally required. We applied the method to histidine where no such information was available a priori, neither about the proton chemical shifts nor about the one-bond scalar coupling constants J( 1 H 15 N), since the protons were invisible due to fast exchange. We have measured the exchange rates of the protons of the imidazole ring and of amino protons in histidine by indirect detection via 15 N. Not only the exchange rate constants, but also the elusive chemical shifts of the protons and the coupling constants could be determined. For the mass spectrometry section, the ion isolation project was initiated to study the effect of phase change of radiofrequency pulses. Excitation of ions in the ICR cell is a linear process, so that the pulse voltage required for ejecting ions must be inversely proportional to the pulse duration. A continuous sweep pulse propels the ion to a higher radius, whereas a phase reversal causes the ion to come to the centre. This represents the principle of 'notch ejection', wherein the ion for which the phase is reversed is retained in the ICR cell, while the remaining ions are ejected. The manuscript also contains a theoretical chapter, wherein the ion trajectories are plotted by solving the Lorentzian equation for the three-pulse scheme used for two-dimensional ICR. Through our simulations we mapped the ion trajectories for different pulse durations and for different phase relations. (author)

Non-Maxwellian fast particle effects in gyrokinetic GENE simulations

Science.gov (United States)

Di Siena, A.; Görler, T.; Doerk, H.; Bilato, R.; Citrin, J.; Johnson, T.; Schneider, M.; Poli, E.; JET Contributors

2018-04-01

Fast ions have recently been found to significantly impact and partially suppress plasma turbulence both in experimental and numerical studies in a number of scenarios. Understanding the underlying physics and identifying the range of their beneficial effect is an essential task for future fusion reactors, where highly energetic ions are generated through fusion reactions and external heating schemes. However, in many of the gyrokinetic codes fast ions are, for simplicity, treated as equivalent-Maxwellian-distributed particle species, although it is well known that to rigorously model highly non-thermalised particles, a non-Maxwellian background distribution function is needed. To study the impact of this assumption, the gyrokinetic code GENE has recently been extended to support arbitrary background distribution functions which might be either analytical, e.g., slowing down and bi-Maxwellian, or obtained from numerical fast ion models. A particular JET plasma with strong fast-ion related turbulence suppression is revised with these new code capabilities both with linear and nonlinear gyrokinetic simulations. It appears that the fast ion stabilization tends to be less strong but still substantial with more realistic distributions, and this improves the quantitative power balance agreement with experiments.

Development of sputter ion pump based SG leak detection system for Fast Breeder Test Reactor

International Nuclear Information System (INIS)

Babu, B.; Sureshkumar, K.V.; Srinivasan, G.

2013-01-01

Highlights: ► Development and commissioning of SG leak detection system for FBTR. ► Development of Robust method of using sputter ion pump based system. ► Modifications for improving reliability and availability. ► On line injection of hydrogen in sodium during reactor operation. ► Triplication of the SG leak detection system. - Abstract: The Fast Breeder Test Reactor (FBTR) is a 40 MWt, loop type sodium cooled fast reactor built at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam as a fore-runner to the second stage of Indian nuclear power programme. The reactor design is based on the French reactor Rapsodie with several modifications which include the provision of a steam-water circuit and turbo-generator. FBTR uses sodium as the coolant in the main heat transport medium to transfer heat from the reactor core to the feed water in the tertiary loop for producing superheated steam, which drives the turbo-generator. Sodium and water flow in shell and tube side respectively, separated by thin-walls of the ferritic steel tubes of the once-through steam generator (SG). Material defects in these tubes can lead to leakage of water into sodium, resulting in sodium water reactions leading to undesirable consequences. Early detection of water or steam leaks into sodium in the steam generator units of liquid metal fast breeder reactors (LMFBR) is an important requirement from safety and economic considerations. The SG leak in FBTR is detected by Sputter Ion Pump (SIP) based Steam Generator Leak Detection (SGLD) system and Thermal Conductivity Detector (TCD) based Hydrogen in Argon Detection (HAD) system. Many modifications were carried out in the SGLD system for the reactor operation to improve the reliability and availability. This paper details the development and the acquired experience of SIP based SGLD system instrumentation for real time hydrogen detection in sodium for FBTR.

Influence of the Coulomb interaction in the final state on the cross section of single-electron capture by fast ions

International Nuclear Information System (INIS)

Novikov, N.V.; Teplova, Ya.A.

2011-01-01

It is shown that the Coulomb interaction of ions in the final state must be taken into account in the estimation of the cross section of electron capture by fast ions. The cross section of electron capture decreases considerably, and the dependence of the cross section on the collision energy becomes close to the experimental one if the interaction of charged particles after collision is taken into account. -- Highlights: → Coulomb interaction of ions in the final state must be taken into account. → This interaction leads to a considerable decrease in the cross section. → The dependence on energy close to the experimental one.

Fast calculator for X-ray emission due to Radiative Recombination and Radiative Electron Capture in relativistic heavy-ion atom collisions

Science.gov (United States)

Herdrich, M. O.; Weber, G.; Gumberidze, A.; Wu, Z. W.; Stöhlker, Th.

2017-10-01

In experiments with highly charged, fast heavy ions the Radiative Recombination (RR) and Radiative Electron Capture (REC) processes have significant cross sections in an energy range of up to a few GeV / u . They are some of the most important charge changing processes in collisions of heavy ions with atoms and electrons, leading to the emission of a photon along with the formation of the ground and excited atomic states. Hence, for the understanding and planning of experiments, in particular for X-ray spectroscopy studies, at accelerator ring facilities, such as FAIR, it is crucial to have a good knowledge of these cross sections and the associated radiation characteristics. In the frame of this work a fast calculator, named RECAL, for the RR and REC process is presented and its capabilities are demonstrated with the analysis of a recently conducted experiment at the Experimental Storage Ring (ESR) at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany. A method is presented to determine unknown X-ray emission cross sections via normalization of the recorded spectra to REC cross sections calculated by RECAL.

Fast ion generation in femto- and picosecond laser plasma at low fluxes of heating radiation

International Nuclear Information System (INIS)

Faenov, A.Ya.; Pikuz, T.A.; Magunov, A.I.

2006-01-01

X-ray spectra from fluoroplastic targets irradiated by laser pulses with duration of 60 fs to 1 ps have been investigated experimentally. It is shown that, when the contrast of the laser pulse is sufficiently low, the effect of self-focusing of the main laser pulse in the plasma produced by the prepulse can significantly enhance the generation efficiency of fast particles. In this case, ions with energies as high as ∼1 MeV are observed at relatively low laser intensities [ru

Two Dual Ion Spectrometer Flight Units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS)

Science.gov (United States)

Adams, Mitzi

2014-01-01

Two Dual Ion Spectrometer flight units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS) have returned to MSFC for flight testing. Anticipated to begin on June 30, tests will ensue in the Low Energy Electron and Ion Facility of the Heliophysics and Planetary Science Office (ZP13), managed by Dr. Victoria Coffey of the Natural Environments Branch of the Engineering Directorate (EV44). The MMS mission consists of four identical spacecraft, whose purpose is to study magnetic reconnection in the boundary regions of Earth's magnetosphere.

The heavy ion therapy project at GSI

International Nuclear Information System (INIS)

Kraft, G.; Becher, W.; Blasche, K.; Boehne, D.; Fischer, B.; Geissel, H.; Haberer, T.; Klabunde, J.; Kraft-Weyrather, W.; Langenbeck, G.; Muenzenberg, G.; Ritter, S.; Roesch, W.; Schardt, D.; Stelzer, H.; Schwab, T.; Gademann, G.

1991-03-01

The use of heavy charged particles in radiotherapy has two major advantages: Firstly, particle beams exhibit a superior dose distribution because of reduced lateral scattering, the finite range of the particles and the increased dose deposition towards the end of the particle track. Secondly, heavy ions exhibit an increased biological efficiency in the region of the increased energy deposition. This diminishes the differences in the radio response between well oxygenated and hypoxic cells as well as differences between fast and slowly proliferating cells. In addition, with high values for relative biological efficiencies, the repair capacity of cells in the tumor are selectively reduced. Both effects, the high energy deposition and the increased RBE values at the end of the particle tracks, are due to the different interaction mechanism of heavy ions with the target material and open a new field of precision and efficiency in radiotherapy. (orig.)

Identification and precise measurements of the wavelengths of high-n transitions in N-, O-, and F-like Zn ions

International Nuclear Information System (INIS)

Fournier, K B; Faenov, A Ya; Pikuz, T A; Magunov, A I; Skobelev, I Yu; Belyaev, V S; Vinogradov, V I; Kyrilov, A S; Matafonov, A P; Flora, F; Bollanti, S; Lazzaro, P Di; Murra, D; Reale, A; Reale, L; Tomassetti, G; Ritucci, A; Francucci, M; Martellucci, S; Petrocelli, G

2003-01-01

We have observed spectra of highly charged zinc ions from a variety of laser-produced plasmas. High-precision measurements of transition wavelengths have been made in the range 6.7-8.6 A, with accuracies of ∼1 mA. Line identifications for high-n transitions (n ≤ 7) in the N-, O-, and F-like spectra of Zn XXIV, XXIII, XXII, respectively, are made by comparison with steady-state collisional-radiative models

Identification and precise measurements of the wavelengths of high-n transitions in N-, O-, and F-like Zn ions

Energy Technology Data Exchange (ETDEWEB)

Fournier, K B [Lawrence Livermore National Laboratory, PO Box 808, L-41, Livermore, CA 94550 (United States); Faenov, A Ya [Multicharged Ions Spectra Data Centre of VNIIFTRI, Moscow, 141570 (Russian Federation); Pikuz, T A [Multicharged Ions Spectra Data Centre of VNIIFTRI, Moscow, 141570 (Russian Federation); Magunov, A I [Multicharged Ions Spectra Data Centre of VNIIFTRI, Moscow, 141570 (Russian Federation); Skobelev, I Yu [Multicharged Ions Spectra Data Centre of VNIIFTRI, Moscow, 141570 (Russian Federation); Belyaev, V S [Central Research Institute of Machine Building, 4, Pionerskaya Street, Korolev, Moscow Region, 141070 (Russian Federation); Vinogradov, V I [Central Research Institute of Machine Building, 4, Pionerskaya Street, Korolev, Moscow Region, 141070 (Russian Federation); Kyrilov, A S [Central Research Institute of Machine Building, 4, Pionerskaya Street, Korolev, Moscow Region, 141070 (Russian Federation); Matafonov, A P [Central Research Institute of Machine Building, 4, Pionerskaya Street, Korolev, Moscow Region, 141070 (Russian Federation); Flora, F [ENEA, Dipartimento Innovazione, Settore Fisica Applicata, 00044 Frascati, Rome (Italy); Bollanti, S [ENEA, Dipartimento Innovazione, Settore Fisica Applicata, 00044 Frascati, Rome (Italy); Lazzaro, P Di [ENEA, Dipartimento Innovazione, Settore Fisica Applicata, 00044 Frascati, Rome (Italy); Murra, D [ENEA, Dipartimento Innovazione, Settore Fisica Applicata, 00044 Frascati, Rome (Italy); Reale, A [Dipartimento di Fisica e INFM, INFN g.c. LNGS, Universita dell' Aquila, 67010 L' Aquila (Italy); Reale, L [Dipartimento di Fisica e INFM, INFN g.c. LNGS, Universita dell' Aquila, 67010 L' Aquila (Italy); Tomassetti, G [Dipartimento di Fisica e INFM, INFN g.c. LNGS, Universita dell' Aquila, 67010 L' Aquila (Italy); Ritucci, A [Dipartimento di Fisica e INFM, INFN g.c. LNGS, Universita dell' Aquila, 67010 L' Aquila (Italy)] [and others

2003-09-28

We have observed spectra of highly charged zinc ions from a variety of laser-produced plasmas. High-precision measurements of transition wavelengths have been made in the range 6.7-8.6 A, with accuracies of {approx}1 mA. Line identifications for high-n transitions (n {<=} 7) in the N-, O-, and F-like spectra of Zn XXIV, XXIII, XXII, respectively, are made by comparison with steady-state collisional-radiative models.

Desorption of Cs+ ions with fast incident atomic and molecular ions

International Nuclear Information System (INIS)

Salehpour, M.; Hunt, J.E.; Tou, L.C.; Hedin, A.; Sundqvist, B.

1988-01-01

Preliminary results on desorption yield measurements of secondary Cs + ions, desorbed as a result of the impact of C + , O + , CO + , O 2 + , CO 2 + and C 4 H 9 + incident ions, in the energy range of 950 keV--3.5 MeV are presented. Molecular beams are found to give high yields of secondary Cs + as a result of impact of O 2 + compared to O + incident ions, indicate no ''collective'' molecular effects. 23 refs., 1 fig

Solid electrolyte batteries and fast ion conducting glasses, factors affecting a proposed merger

Energy Technology Data Exchange (ETDEWEB)

Uhlmann, D R; Tuller, H L; Button, D P; Valez, M [Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Materials Science and Engineering

1983-01-01

The present paper is concerned with advanced battery systems employing glass as a solid electrolyte. After an initial discussion of battery systems employing solid electrolytes, and of the attractive features offered by glass electrolytes, consideration is given to batteries fabricated with such electrolytes and to their performance characteristics. Subsequent discussion is directed to the two principal characteristics of glasses which are critical to their use as solid electrolytes - viz., their electrical conductivity and resistance to corrosive attack. The present state of knowledge in each of these areas is summarized, with particular focus on glasses with exceptionally high ionic conductivities - so-called fast ion conductors or FIC's.

Poloidal asymmetries of the heavy ions in the ASDEX Upgrade tokamak

Energy Technology Data Exchange (ETDEWEB)

Odstrcil, Tomas [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Physik-Department E28, Technische Universitaet Muenchen, Garching (Germany); Puetterich, Thomas; Angioni, Clemente; Bilato, Roberto; Gude, Anja; Vezinet, Didier [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Mazon, Didier [CEA, IRFM, Saint Paul-lez-Durance (France); Collaboration: ASDEX Upgrade Team

2015-05-01

Poloidal asymmetries of heavy ions in the tokamak plasma are caused by the presence of forces parallel with field-lines which have comparable magnitude to the thermal pressure. The most important examples are the centrifugal force (CF) and the electric force (EF). The CF is caused by fast toroidal rotation of the plasma column which is pushing impurity ions, that have a substantially higher mass than the main ions, on the outer-side of the plasma. And the EF can be produced by ion cyclotron heated fast particles with high pitch angle that are trapped by the mirror force on the low field side of the plasma. The excessive charge produced by these particles is affecting highly charged impurities and pushing them to the high field side of the plasma. From predictions based on neoclassical and turbulent theory, it follows that the radial flux of heavy ions will be significantly changed by the presence of these asymmetries. The purpose of this study is to investigate the presence of these asymmetries in ASDEX Upgrade and verify the predicted consequences on the particles flux. High intrinsic content of the tungsten in AUG plasma makes this device well suitable for such studies. Precise measurement of the SXR (soft-X-ray) radiation profiles has identified a presence of CF generated asymmetries in every NBI heated Asdex discharge. Poloidal asymmetry should than lead to the significant change in the neoclassical and turbulent radial transport of these heavy ions. High intrinsic content of the tungsten in Asdex plasma makes this device well suitable for studying these asymmetries. Precise measurement of the SXR (soft-X-ray) radiation profiles has identified a presence of CF generated asymmetries in every NBI heated Asdex discharge. For heavy and highly charged impurities multiple mechanisms exist that produce non-constant impurities densities on the flux surfaces. As for neoclassical and turbulent transport models such an asymmetry is of highly importance an effort is

Prompt loss of beam ions in KSTAR plasmas

Directory of Open Access Journals (Sweden)

Jun Young Kim

2016-10-01

Full Text Available For a toroidal plasma facility to realize fusion energy, researching the transport of fast ions is important not only due to its close relation to the heating and current drive efficiencies but also to determine the heat load on the plasma-facing components. We present a theoretical analysis and orbit simulation for the origin of lost fast-ions during neutral beam injection (NBI heating in Korea Superconducting Tokamak Advanced Research (KSTAR device. We adopted a two-dimensional phase diagram of the toroidal momentum and magnetic moment and describe detectable momentums at the fast-ion loss detector (FILD position as a quadratic line. This simple method was used to model birth ions deposited by NBI and drawn as points in the momentum phase space. A Lorentz orbit code was used to calculate the fast-ion orbits and present the prompt loss characteristics of the KSTAR NBI. The scrape-off layer deposition of fast ions produces a significant prompt loss, and the model and experimental results closely agreed on the pitch-angle range of the NBI prompt loss. Our approach can provide wall load information from the fast ion loss.

A LaBr{sub 3}: Ce fast-timing array for DESPEC at FAIR

Energy Technology Data Exchange (ETDEWEB)

Roberts, Oliver J., E-mail: O.J.Roberts@brighton.ac.uk [School of Computing, Engineering and Mathematics, University of Brighton, Brighton BN2 4GJ (United Kingdom); Bruce, Alison M. [School of Computing, Engineering and Mathematics, University of Brighton, Brighton BN2 4GJ (United Kingdom); Regan, Patrick H. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); National Physics Laboratory, Teddington, TW11 0LW (United Kingdom); Podolyák, Zsolt; Townsley, Christopher M. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Smith, John F.; Mulholland, Kieran F. [School of Engineering, The University of the West of Scotland, Paisley PA1 2BE (United Kingdom); Smith, Andrew [The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)

2014-06-01

The design of a fast-timing γ-ray detection array aimed at measuring sub-nanosecond half-lives using LaBr{sub 3}:Ce scintillation crystals is presented. This array will complement novel and existing charged particle and neutron detector arrays at the low-energy branch of a fragment separator (Super-FRS) to be built within the NuSTAR collaboration as part of the future Facility for Anti-proton and Ion Research (FAIR). The array will be used in conjunction with the Advanced Implantation Detector Array (AIDA), to measure implant-decay correlations. Monte-Carlo simulations have been performed to determine the design of the proposed fast-timing array around a localised implantation point. In particular, simulations were used to determine the full-energy peak efficiencies for single cylindrical, conical and ‘hybrid’ detector geometries, as well as complete array configurations of ‘hybrid’ and ∅1.5 in.×2 in. cylindrical crystals. Timing precision calculations were then used to determine the timing response for each configuration based on its simulated efficiency. An informed decision based on the simulated efficiencies and timing precision calculations allowed the optimum configuration for the array to be determined.

Ejection of fast recoil atoms from solids under ion bombardment (medium-energy ion scattering by solid surfaces: Pt. 3)

International Nuclear Information System (INIS)

Dodonoy, A.I.; Mashkova, E.S.; Molchanov, V.A.

1989-01-01

This paper is the third part of our review surface scattering. Part I, which was devoted to the scattering of ions by the surfaces of disordered solids, was published in 1972; Part II, concerning scattering by crystal surfaces, was published in 1974. Since the publication of these reviews the material contained in them has become obsolete in many respects. A more recent account of the status of the problem has been given in a number of studies, including the book by E.S. Mashkova and V.A. Molchanov, Medium-Energy Ion Scattering by Solid Surfaces (Atomizdat, Moscow, 1980), than extended version of which was published by North-Holland in 1985. We note, however, that at the time these reviews were written the study of fast recoil atoms had not been carried out systematically; the problem was studied only as a by-product of surface scattering and sputtering. For this reason, in the above-mentioned works and in other reviews the data relating to recoil atoms were considered only occasionally. In recent years there have appeared a number of works - theoretical, experimental and computer -specially devoted to the study of the ejection of recoil atoms under ion bombardment. A number of interesting effects, which are due to the crystal structure of the target, have been discovered. It therefore, appeared desirable to us to systematize the available material and to present it as Part III of our continuing review. (author)

Precise and accurate isotope ratio measurements by ICP-MS.

Science.gov (United States)

Becker, J S; Dietze, H J

2000-09-01

The precise and accurate determination of isotope ratios by inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) is important for quite different application fields (e.g. for isotope ratio measurements of stable isotopes in nature, especially for the investigation of isotope variation in nature or age dating, for determining isotope ratios of radiogenic elements in the nuclear industry, quality assurance of fuel material, for reprocessing plants, nuclear material accounting and radioactive waste control, for tracer experiments using stable isotopes or long-lived radionuclides in biological or medical studies). Thermal ionization mass spectrometry (TIMS), which used to be the dominant analytical technique for precise isotope ratio measurements, is being increasingly replaced for isotope ratio measurements by ICP-MS due to its excellent sensitivity, precision and good accuracy. Instrumental progress in ICP-MS was achieved by the introduction of the collision cell interface in order to dissociate many disturbing argon-based molecular ions, thermalize the ions and neutralize the disturbing argon ions of plasma gas (Ar+). The application of the collision cell in ICP-QMS results in a higher ion transmission, improved sensitivity and better precision of isotope ratio measurements compared to quadrupole ICP-MS without the collision cell [e.g., for 235U/238U approximately 1 (10 microg x L(-1) uranium) 0.07% relative standard deviation (RSD) vs. 0.2% RSD in short-term measurements (n = 5)]. A significant instrumental improvement for ICP-MS is the multicollector device (MC-ICP-MS) in order to obtain a better precision of isotope ratio measurements (with a precision of up to 0.002%, RSD). CE- and HPLC-ICP-MS are used for the separation of isobaric interferences of long-lived radionuclides and stable isotopes by determination of spallation nuclide abundances in an irradiated tantalum target.

Adsorption of cadmium (II) ions from aqueous solution by a new low-cost adsorbent-Bamboo charcoal

Energy Technology Data Exchange (ETDEWEB)

Wang Fayuan [State Key Joint Laboratory of Environment Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Qinghuayuan, Haidian District, Beijing 100084 (China); Wang Hui, E-mail: wanghui@mail.tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Qinghuayuan, Haidian District, Beijing 100084 (China); Ma Jianwei [State Key Joint Laboratory of Environment Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Qinghuayuan, Haidian District, Beijing 100084 (China)

2010-05-15

Batch adsorption experiments were conducted for the adsorption of Cd (II) ions from aqueous solution by bamboo charcoal. The results showed that the adsorption of Cd (II) ions was very fast initially and the equilibrium time was 6 h. High pH ({>=}8.0) was favorable for the adsorption and removal of Cd (II) ions. Higher initial Cd concentrations led to lower removal percentages but higher adsorption capacity. As the adsorbent dose increased, the removal of Cd increased, while the adsorption capacity decreased. Adsorption kinetics of Cd (II) ions onto bamboo charcoal could be best described by the pseudo-second-order model. The adsorption behavior of Cd (II) ions fitted Langmuir, Temkin and Freundlich isotherms well, but followed Langmuir isotherm most precisely, with a maximum adsorption capacity of 12.08 mg/g. EDS analysis confirmed that Cd (II) was adsorbed onto bamboo charcoal. This study demonstrated that bamboo charcoal could be used for the removal of Cd (II) ions in water treatment.

Thermal ions dilution and ITG suppression in ASDEX Upgrade ion ITBs

International Nuclear Information System (INIS)

Tardini, G.; Hobirk, J.; Igochine, V.G.; Maggi, C.F.; Martin, P.; McCune, D.; Peeters, A.G.; Sips, A.C.C.; Staebler, A.; Stober, J.

2007-01-01

Internal transport barriers (ITBs) in the ion channel in the tokamak ASDEX Upgrade allow for high energy confinement but collapse after only several energy confinement times. In this paper we show that in most cases the ITB phase is terminated clearly before the first ELM burst, thereby ruling out the ELMs as the main trigger of the ITB collapse. For the first time, the ITB formation and sustainment are found to be associated with a mechanism of transport suppression based on thermal ions dilution by the injected fast ions. Interestingly, such ITBs do not require reversed magnetic shear. The linear growth rate of the ion temperature gradient driven mode is computed as a function of the fast ion fraction with gyrokinetic stability analysis. Monte Carlo simulations predict the fast ion population to be above the gyrokinetic critical fraction in a region consistent with the experimental ITB width. The density threshold documented for the onset of ASDEX Upgrade ion ITBs is explained. The role of T i /T e and of the plasma sheared rotation for ITB sustainment are analysed. The stabilization mechanism presented here is consistent with the observed ITB lifetime of the order of the beam slowing down time. A possible runaway mechanism leading to ITB collapse is described. Finally, the relevance of this particular ITB scheme for ITER is discussed

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.

Ion beam analysis in art and archaeology: attacking the power precisions paradigm

International Nuclear Information System (INIS)

Abraham, Meg

2004-01-01

It is a post-modern axiom that the closer one looks at something the more blinkered is the view, thus the result is often a failure to see the whole picture. With this in mind, the value of a tool for art and archaeology applications is greatly enhanced if the information is scientifically precise and yet is easily integrated into the broader study regarding the objects at hand. Art and archaeological objects offer some unique challenges for researchers. First, they are almost always extraordinarily inhomogeneous across individual pieces and across types. Second they are often valuable and delicate so sampling is discouraged. Finally, in most cases, each piece is unique, thus the data is also unique and is of greatest value when incorporated into the overall understanding of the object or of the culture of the artisan. Ion beam analysis solves many of these problems. With IBA, it is possible to avoid sampling by using an external beam setup or by manipulating small objects in a vacuum. The technique is largely non-destructive, allowing for multiple data points to be taken across an object. The X-ray yields are from deeper in the sample than those of other techniques and using RBS one can attain bulk concentrations from microns into the sample. And finally, the resulting X-ray spectra is easily interpreted and understood by many conservators and curators, while PIXE maps are a wonderful visual record of the results of the analysis. Some examples of the special role that ion beam analysis plays in the examination of cultural objects will be covered in this talk

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 and computer modeling of fast ion emission from plasma accelerators of the rod plasma injector type

International Nuclear Information System (INIS)

Malinowski, Karol; Sadowski, Marek J; Skladnik-Sadowska, Elzbieta

2014-01-01

This paper reports on the results of experimental studies and computer simulations of the emission of fast ion streams from so-called rod plasma injectors (RPI). Various RPI facilities have been used at the National Centre for Nuclear Research (NCBJ) for basic plasma studies as well as for material engineering. In fact, the RPI facilities have been studied experimentally for many years, particularly at the Institute for Nuclear Sciences (now the NCBJ), and numerous experimental data have been collected. Unfortunately, the ion emission characteristics have so far not been explained theoretically in a satisfactory way. In this paper, in order to explain these characteristics, use was made of a single-particle model. Taking into account the stochastic character of the ion emission, we applied a Monte Carlo method. The performed computer simulations of a pinhole image and energy spectrum of deuterons emitted from RPI-IBIS, which were computed on the basis of the applied model, appeared to be in reasonable agreement with the experimental data. (paper)

Precision and reproducibility in AMS radiocarbon measurements.

Energy Technology Data Exchange (ETDEWEB)

Hotchkis, M.A.; Fink, D.; Hua, Q.; Jacobsen, G.E.; Lawson, E. M.; Smith, A.M.; Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Accelerator Mass Spectrometry (AMS) is a technique by which rare radioisotopes such as {sup 14}C can be measured at environmental levels with high efficiency. Instead of detecting radioactivity, which is very weak for long-lived environmental radioisotopes, atoms are counted directly. The sample is placed in an ion source, from which a negative ion beam of the atoms of interest is extracted, mass analysed, and injected into a tandem accelerator. After stripping to positive charge states in the accelerator HV terminal, the ions are further accelerated, analysed with magnetic and electrostatic devices and counted in a detector. An isotopic ratio is derived from the number of radioisotope atoms counted in a given time and the beam current of a stable isotope of the same element, measured after the accelerator. For radiocarbon, {sup 14}C/{sup 13}C ratios are usually measured, and the ratio of an unknown sample is compared to that of a standard. The achievable precision for such ratio measurements is limited primarily by {sup 14}C counting statistics and also by a variety of factors related to accelerator and ion source stability. At the ANTARES AMS facility at Lucas Heights Research Laboratories we are currently able to measure {sup 14}C with 0.5% precision. In the two years since becoming operational, more than 1000 {sup 14}C samples have been measured. Recent improvements in precision for {sup 14}C have been achieved with the commissioning of a 59 sample ion source. The measurement system, from sample changing to data acquisition, is under common computer control. These developments have allowed a new regime of automated multi-sample processing which has impacted both on the system throughput and the measurement precision. We have developed data evaluation methods at ANTARES which cross-check the self-consistency of the statistical analysis of our data. Rigorous data evaluation is invaluable in assessing the true reproducibility of the measurement system and aids in

Precision and reproducibility in AMS radiocarbon measurements.

Energy Technology Data Exchange (ETDEWEB)

Hotchkis, M A; Fink, D; Hua, Q; Jacobsen, G E; Lawson, E M; Smith, A M; Tuniz, C [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Accelerator Mass Spectrometry (AMS) is a technique by which rare radioisotopes such as {sup 14}C can be measured at environmental levels with high efficiency. Instead of detecting radioactivity, which is very weak for long-lived environmental radioisotopes, atoms are counted directly. The sample is placed in an ion source, from which a negative ion beam of the atoms of interest is extracted, mass analysed, and injected into a tandem accelerator. After stripping to positive charge states in the accelerator HV terminal, the ions are further accelerated, analysed with magnetic and electrostatic devices and counted in a detector. An isotopic ratio is derived from the number of radioisotope atoms counted in a given time and the beam current of a stable isotope of the same element, measured after the accelerator. For radiocarbon, {sup 14}C/{sup 13}C ratios are usually measured, and the ratio of an unknown sample is compared to that of a standard. The achievable precision for such ratio measurements is limited primarily by {sup 14}C counting statistics and also by a variety of factors related to accelerator and ion source stability. At the ANTARES AMS facility at Lucas Heights Research Laboratories we are currently able to measure {sup 14}C with 0.5% precision. In the two years since becoming operational, more than 1000 {sup 14}C samples have been measured. Recent improvements in precision for {sup 14}C have been achieved with the commissioning of a 59 sample ion source. The measurement system, from sample changing to data acquisition, is under common computer control. These developments have allowed a new regime of automated multi-sample processing which has impacted both on the system throughput and the measurement precision. We have developed data evaluation methods at ANTARES which cross-check the self-consistency of the statistical analysis of our data. Rigorous data evaluation is invaluable in assessing the true reproducibility of the measurement system and aids in

Spectroscopy of multi-charged ions: a short review

International Nuclear Information System (INIS)

Berry, H.G.

1983-01-01

Recent and future applications of multiply charged ions to spectroscopy and atomic structure are discussed. The experimental techniques use either very fast ions produced in heavy ion accelerators, or slow ions produced directly both in electron beam ion sources and from collisions of fast accelerated ions. For the accelerated fast ions, spectroscopic measurements on using gas target excitation, solid foil excitation and laser excitation. In gas target excitation, both X-ray and electron spectroscopy have been applied to analyse atomic structures and secondary collision effects. Highlycharged secondary ions have also been trapped electro-magnetically for further similar studies in controlled conditions. Spectroscopic detection following solid foil interaction has led to atomic lifetime measurements, principally of metastable level, analysis of complex highly-ionized heavy ion spectra, and investigations of relativistic and QED effects in few electron ions

Fast wave current drive

International Nuclear Information System (INIS)

Goree, J.; Ono, M.; Colestock, P.; Horton, R.; McNeill, D.; Park, H.

1985-07-01

Fast wave current drive is demonstrated in the Princeton ACT-I toroidal device. The fast Alfven wave, in the range of high ion-cyclotron harmonics, produced 40 A of current from 1 kW of rf power coupled into the plasma by fast wave loop antenna. This wave excites a steady current by damping on the energetic tail of the electron distribution function in the same way as lower-hybrid current drive, except that fast wave current drive is appropriate for higher plasma densities

A possible mechanism in heavy ion induced reactions: 'fast fission process'

International Nuclear Information System (INIS)

Borderie, B.; Gardes, D.; Berlanger, M.

1980-01-01

The influence of the orbital angular momentum l on the mass distribution of fission fragments is studied, both on previously available data on heavy ion induced fission and in new specifically planned experiments: systems 40 Ar + 165 Ho and 24 Mg + 181 Ta at bombarding energies ranging from 180 up to 391 MeV and leading to the same fissionning nucleus 205 At wigh different l distributions. When l values corresponding to a vanished fission barrier are reached, the mass distribution broadens. This suggest the existence of a specific process, 'fast fission', at l-values leading to compound nucleus formation and deep inelastic collisions, respectively. This process and its conditions of occurrence are discussed; of special interest are the correlated differences between the limitations to the fission cross-section and the fission mass distributions broadenings, respectively, for the Ar + Ho and Mg + Ta systems

Recent Developments in High-Harmonic Fast Wave Physics in NSTX

International Nuclear Information System (INIS)

LeBlanc, B.P.; Bell, R.E.; Bonoli, P.; Harvey, R.; Heidbrink, W.W.; Hosea, J.C.; Kaye, S.M.; Liu, D.; Maingi, R.; Medley, S.S.; Ono, M.; Podesta, M.; Phillips, C.K.; Ryan, P.M.; Roquemore, A.L.; Taylor, G.; Wilson, J.R.

2010-01-01

Understanding the interaction between ion cyclotron range of frequency (ICRF) fast waves and the fast-ions created by neutral beam injection (NBI) is critical for future devices such as ITER, which rely on a combination ICRF and NBI. Experiments in NSTX which use 30 MHz High-Harmonic Fast-Wave (HHFW) ICRF and NBI heating show a competition between electron heating via Landau damping and transit-time magnetic pumping, and radio-frequency wave acceleration of NBI generated fast ions. Understanding and mitigating some of the power loss mechanisms outside the last closed flux surface (LCFS) has resulted in improved HHFW heating inside the LCFS. Nevertheless a significant fraction of the HHFW power is diverted away from the enclosed plasma. Part of this power is observed locally on the divertor. Experimental observations point toward the radio-frequency (RF) excitation of surface waves, which disperse wave power outside the LCFS, as a leading loss mechanism. Lithium coatings lower the density at the antenna, thereby moving the critical density for perpendicular fast-wave propagation away from the antenna and surrounding material surfaces. Visible and infrared imaging reveal flows of RF power along open field lines into the divertor region. In L-mode -- low average NBI power -- conditions, the fast-ion D-alpha (FIDA) diagnostic measures a near doubling and broadening of the density profile of the upper energetic level of the fast ions concurrent with the presence of HHFW power launched with k// = -8m-1. We are able to heat NBI-induced H-mode plasmas with HHFW. The captured power is expected to be split between absorption by the electrons and absorption by the fast ions, based on TORIC calculation. In the case discussed here the Te increases over the whole profile when ∼2MW of HHFW power with antenna k// = 13m-1 is applied after the H-mode transition. But somewhat unexpectedly fast-ion diagnostics do not observe a change between the HHFW heated NBI discharge and the

Advances in surface ion suppression from RILIS: Towards the Time-of-Flight Laser Ion Source (ToF-LIS)

CERN Document Server

Rothe, S; Crepieux, B; Day Goodacre, T; Fedosseev, V N; Giles, T; Marsh, B A; Ramos, J P; Rossel, R E

2016-01-01

We present results from the development towards the Time-of-Flight Laser Ion Source (ToF-LIS) aiming for the suppression of isobaric contaminants through fast beam gating. The capability to characterize high resistance ion sources has been successfully demonstrated. A ninefold selectivity gain has been achieved through suppression of surface ionized potassium, while maintaining >90% transmission for laser-ionized gallium using a thin wall graphite ionizer cavity combined with a fast beam gate. Initial results from the investigation of glassy carbon as a potential hot cavity ion source are presented. Power-cycle tests of a newly designed mount for fragile ion source cavities indicates its capability to survive the thermal stress expected during operation in an ISOLDE target unit. Finally, we introduce fast ion beam switching at a rate of 10 kHz using the ISOLDE ion beam switchyard as a new concept for ion beam distribution and conclude by highlighting the potential applications of this ion beam multiplexing te...

Interaction of supra-thermal ions with turbulence in a magnetized toroidal plasma

International Nuclear Information System (INIS)

Plyushchev, G.

2009-01-01

This thesis addresses the interaction of a supra-thermal ion beam with turbulence in the simple magnetized toroidal plasma of TORPEX. The first part of the Thesis deals with the ohmic assisted discharges on TORPEX. The aim of these discharges is the investigation of the open to closed magnetic field line transition. The relevant magnetic diagnostics were developed. Ohmic assisted discharges with a maximum plasma current up to 1 kA are routinely obtained. The equilibrium conditions on the vacuum magnetic field configuration were investigated. In the second part of the Thesis, the design of the fast ion source and detector are discussed. The accelerating electric field needed for the fast ion source was optimized. The fast ion source was constructed and commissioned. To detect the fast ions a specially designed gridded energy analyzer was used. The electron energy distribution function was obtained to demonstrate the efficiency of the detector. The experiments with the fast ion beam were conducted in different plasma regions of TORPEX. In the third part of the Thesis, numerical simulations are used to interpret the measured fast ion beam behavior. It is shown that a simple single particle equation of motion explains the beam behavior in the experiments in the absence of plasma. To explain the fast ion beam experiments with the plasma a turbulent electric field must be used. The model that takes into account this turbulent electrical field qualitatively explains the shape of the fast ion current density profile in the different plasma regions of TORPEX. The vertically elongated fast ion current density profiles are explained by a spread in the fast ion velocity distribution. The theoretically predicted radial fast ion beam spreading due to the turbulent electric field was observed in the experiment. (author)

Analysis techniques for diagnosing runaway ion distributions in the reversed field pinch

Energy Technology Data Exchange (ETDEWEB)

Kim, J., E-mail: jkim536@wisc.edu; Anderson, J. K.; Capecchi, W.; Bonofiglo, P. J.; Sears, S. H. [University of Wisconsin—Madison, Madison, Wisconsin 53706 (United States)

2016-11-15

An advanced neutral particle analyzer (ANPA) on the Madison Symmetric Torus measures deuterium ions of energy ranges 8-45 keV with an energy resolution of 2-4 keV and time resolution of 10 μs. Three different experimental configurations measure distinct portions of the naturally occurring fast ion distributions: fast ions moving parallel, anti-parallel, or perpendicular to the plasma current. On a radial-facing port, fast ions moving perpendicular to the current have the necessary pitch to be measured by the ANPA. With the diagnostic positioned on a tangent line through the plasma core, a chord integration over fast ion density, background neutral density, and local appropriate pitch defines the measured sample. The plasma current can be reversed to measure anti-parallel fast ions in the same configuration. Comparisons of energy distributions for the three configurations show an anisotropic fast ion distribution favoring high pitch ions.

Spectrum response and analysis of 77 GHz band collective Thomson scattering diagnostic for bulk and fast ions in LHD plasmas

DEFF Research Database (Denmark)

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

2014-01-01

A collective Thomson scattering (CTS) diagnostic was developed and used to measure the bulk and fast ions originating from 180 keV neutral beams in the Large Helical Device (LHD). Electromagnetic waves from a gyrotron at 77 GHz with 1 MW power output function as both the probe and electron cyclot...

Utilization of the ion traps by SPIRAL

International Nuclear Information System (INIS)

Le Brun, C.; Lienard, E.; Mauger, F.; Tamain, B.

1997-01-01

An ion trap is a device capable of confine particles, ions or atoms in a well-controlled environment isolated from any exterior perturbations. There are different traps. They are utilized to collect or stock ions, to cool them after in order to subject them to high precision measurement of masses, magnetic moments, hyperfine properties, beta decay properties, etc. Some dozen of traps are currently used all over the world to study stable or radioactive ions.. SPIRAL has been designed and built to produce radioactive ions starting from various heavy ion beams. SPIRAL has the advantage that the projectile parameters, the target and the energy can be chosen to optimize the production in various regions of the nuclear chart. Also, in SPIRAL it is possible to extract more rapidly the radioactive ions formed in the targets. In addition, in SPIRAL the multicharged ion production in a ECR source is possible. The utilization of multicharged ions is indeed very useful for fast mass measurements or for the study of the interaction between the nucleus and the electronic cloud. Finally, utilization of a ion trap on SPIRAL can be designed first at the level of production target by installing a low energy output line. Than, the trap system could be up-graded and brought to its full utilization behind of the recoil spectrometer. It must be capable of selecting and slowing down the ions produced in the reactions (fusion transfer, very inelastic collisions, etc.) induced by the radioactive ions accelerated in CIME. At present, the collaboration is debating on the most favored subject to study and the most suited experimental setups. The following subjects were selected: ion capture, purification and manipulation; isomers (separation and utilization); mass measurements; hyperfine interactions; lifetimes, nuclear electric cloud; β decays; study of the N = Z nuclei close to the proton drip line; physical and chemical properties of transuranium systems

Status and outlook of CHIP-TRAP: The Central Michigan University high precision Penning trap

Science.gov (United States)

Redshaw, M.; Bryce, R. A.; Hawks, P.; Gamage, N. D.; Hunt, C.; Kandegedara, R. M. E. B.; Ratnayake, I. S.; Sharp, L.

2016-06-01

At Central Michigan University we are developing a high-precision Penning trap mass spectrometer (CHIP-TRAP) that will focus on measurements with long-lived radioactive isotopes. CHIP-TRAP will consist of a pair of hyperbolic precision-measurement Penning traps, and a cylindrical capture/filter trap in a 12 T magnetic field. Ions will be produced by external ion sources, including a laser ablation source, and transported to the capture trap at low energies enabling ions of a given m / q ratio to be selected via their time-of-flight. In the capture trap, contaminant ions will be removed with a mass-selective rf dipole excitation and the ion of interest will be transported to the measurement traps. A phase-sensitive image charge detection technique will be used for simultaneous cyclotron frequency measurements on single ions in the two precision traps, resulting in a reduction in statistical uncertainty due to magnetic field fluctuations.

Fast and precise luminosity measurement at the international linear

Indian Academy of Sciences (India)

The detectors of the ILC will feature a calorimeter system in the very forward region. The system comprises mainly two electromagnetic calorimeters: LumiCal, which is dedicated to the measurement of the absolute luminosity with highest precision and BeamCal, which uses the energy deposition from beamstrahlung pairs ...

Quadrupole Ion Traps

Indian Academy of Sciences (India)

to do precision spectroscopic measurements on these ions. ... Bonn, investigated the non-magnetic quadrupole mass filter, .... the details of which will be discussed in the subse- ... the radial plane the ion undergoes a circular motion with the.

Neutron spectroscopy measurements and modeling of neutral beam heating fast ion dynamics

International Nuclear Information System (INIS)

Hellesen, C; Sunden, E Andersson; Conroy, S; Ericsson, G; Johnson, M Gatu; Hjalmarsson, A; Kaellne, J; Ronchi, E; Sjoestrand, H; Weiszflog, M; Albergante, M; Ballabio, L; Gorini, G; Tardocchi, M; Giacomelli, L; Jenkins, I; Voitsekhovitch, I

2010-01-01

The energy spectrum of the neutron emission from beam-target reactions in fusion plasmas at the Joint European Torus (JET) has been investigated. Different beam energies as well as injection angles were used. Both measurements and simulations of the energy spectrum were done. The measurements were made with the time-of-flight spectrometer TOFOR. Simulations of the neutron spectrum were based on first-principle calculations of neutral beam deposition profiles and the fast ion slowing down in the plasma using the code NUBEAM, which is a module of the TRANSP package. The shape of the neutron energy spectrum was seen to vary significantly depending on the energy of the beams as well as the injection angle and the deposition profile in the plasma. Cross validations of the measured and modeled neutron energy spectra were made, showing a good agreement for all investigated scenarios.

Catapult mechanism for fast particle emission in fission and heavy ion reactions

International Nuclear Information System (INIS)

Maedler, P.

1984-01-01

The fission processes of slabs of nuclear matter is modelled in the Hartree-Fock time dependence approximation by adding an initial collective velocity field to the static self-consistent solution. In dependence on its amplitude either large amplitude density oscillations are excited or fission occurs. The final disintegration of the slab proceeds on a time scale 10 -22 s and is characterized by a sharp peak in the actual velocity field in the region of the ''snatching'' inner low density tails. A characteristic time later a low density lump correlated with a peak in the velocity field energies in front of the fragments. These particles are called ''catapult particles''. Recent experimental results possibly provide evidence for catapult neutrons in low-energy fission. The significance of the catapult mechanism for fast particle emission in the exit channel of heavy ion reactions is discussed

Multi-phase simulation of fast ion profile flattening due to Alfvén eigenmodes in a DIII-D experiment

International Nuclear Information System (INIS)

Todo, Y.; Van Zeeland, M.A.; Bierwage, A.; Heidbrink, W.W.

2014-01-01

A multi-phase simulation that is a combination of classical simulation and hybrid simulation for energetic particles interacting with a magnetohydrodynamic (MHD) fluid is developed to simulate the nonlinear dynamics on the slowing down time scale of the energetic particles. The hybrid simulation code is extended with realistic beam deposition profile, collisions and losses, and is used for both the classical and hybrid phases. The code is run without MHD perturbations in the classical phase, while the interaction between the energetic particles and the MHD fluid is simulated in the hybrid phase. In a multi-phase simulation of DIII-D discharge #142111, the stored beam ion energy is saturated due to Alfvén eigenmodes (AE modes) at a level lower than in the classical simulation. After the stored fast ion energy is saturated, the hybrid simulation is run continuously. It is demonstrated that the fast ion spatial profile is significantly flattened due to the interaction with the multiple AE modes with amplitude v/v A  ∼ δB/B ∼ O(10 −4 ). The dominant AE modes are toroidal Alfvén eigenmodes (TAE modes), which is consistent with the experimental observation at the simulated moment. The amplitude of the temperature fluctuations brought about by the TAE modes is of the order of 1% of the equilibrium temperature. This is also comparable with electron cyclotron emission measurements in the experiment. (paper)

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.

Exit points, on plasma, of lost fast ions during NBI in TJ-II; Puntos de salida en el plasma de los iones rapidos durante NBI en el TJ-II

Energy Technology Data Exchange (ETDEWEB)

Guasp, J.

1995-07-01

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.

Ion temperature via laser scattering on ion Bernstein waves

International Nuclear Information System (INIS)

Wurden, G.A.; Ono, M.; Wong, K.L.

1981-10-01

Hydrogen ion temperature has been measured in a warm toroidal plasma with externally launched ion Bernstein waves detected by heterodyne CO 2 laser scattering. Radial scanning of the laser beam allows precise determination of k/sub perpendicular to/ for the finite ion Larmor radius wave (ω approx. less than or equal to 2Ω/sub i/). Knowledge of the magnetic field strength and ion concentration then give a radially resolved ion temperature from the dispersion relation. Probe measurements and Doppler broadening of ArII 4806A give excellent agreement

Effect of variation in the glass-former network structure on the relaxation properties of conductive Ag+ ions in AgI-based fast ion conducting glasses

Science.gov (United States)

Hanaya, Minoru; Nakayama, Michiko; Hatate, Atsuo; Oguni, Masaharu

1995-08-01

Heat capacities and ac conductivities of AgI-based fast ion conducting glasses of AgI-Ag2O-P2O5 and AgI-Ag2O-B2O3 systems with different P-O or B-O network structures but with the same AgI concentration of 1.55×104 mol m-3 were measured in the temperature range 14-400 K and in the temperature and frequency ranges 100-200 K and 10 Hz-1 MHz, respectively. The β-glass transition due to a freezing-in of the rearrangement of Ag+ ions was observed by adiabatic calorimetry for the glasses in the liquid-nitrogen temperature region, and the conductometry was suggested to see the same mode of Ag+-ion motion as the calorimetry. It was found that the development of the network structure of the glass former at constant AgI concentration resulted in the decrease of the β-glass transition temperature and the activation energy for the diffusional motion of Ag+ ions and in the increase of the heat-capacity jump associated with the glass transition. The results support the amorphous AgI aggregate model for the structure of the conductive region in the glasses with relatively high AgI compositions, indicating that Ag+-ion conductivity is mainly dominated by the degree of development of the AgI aggregate region dependent on the glass-former network structure as well as the AgI composition.

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.)

Medical heavy ion accelerator proposals

International Nuclear Information System (INIS)

Gough, R.A.

1985-05-01

For several decades, accelerators designed primarily for research in nuclear and high energy physics have been adapted for biomedical research including radiotherapeutic treatment of human diseases such as pituitary disorders, cancer, and more recently, arteriovascular malformations. The particles used in these treatments include pions, protons and heavier ions such as carbon, neon, silicon and argon. Maximum beam energies must be available to penetrate into an equivalent of about 30 cm of water, requiring treatment beams of 250 to 1000 MeV/nucleon. Certain special treatments of superficial melanoma, however, require that beam energies as low as 70 MeV/nucleon also be available. Intensities must be adequate to complete a 100 rad treatment fraction in about 1 minute. For most heavy ion treatments, this corresponds to 10 7 -10 9 ions/second at the patient. Because this research is best conducted in a dedicated, hospital-based facility, and because of the clinical need for ultra-high reliability, the construction of new and dedicated facilities has been proposed. Heavy ion accelerators can provide a variety of ions and energies, permitting treatment plans that exploit the properties of the ion best suited to each individual treatment, and that employ radioactive beams (such as 11 C and 19 Ne) to precisely confirm the dose localization. The favored technical approach in these proposals utilizes a conventional, strong-focusing synchrotron capable of fast switching between ions and energies, and servicing multiple treatment rooms. Specialized techniques for shaping the dose to conform to irregularly-shaped target volumes, while simultaneously sparing surrounding, healthy tissue and critical structures, are employed in each treatment room, together with the sophisticated dosimetry necessary for verification, monitoring, and patient safety. 3 refs., 8 figs

Advanced ion beam analysis of materials using ion-induced fast electron

Energy Technology Data Exchange (ETDEWEB)

Kudo, Hiroshi; Tanabe, Atsushi; Ishihara, Toyoyuki [Tsukuba Univ., Ibaraki (Japan); and others

1997-03-01

Recent progress in the study of high-energy shadowing effect using ion-induced electron spectroscopy is reported with emphasis on a possibility of determination of local electronic structure in solids, which has been a difficult problem to approach with other experimental techniques. We demonstrate real-space determination of covalent-bond electron distribution in Si crystal. The analysis technique may provide a new field of ion beam analysis of solids. (author)

Fast optimization and dose calculation in scanned ion beam therapy

International Nuclear Information System (INIS)

Hild, S.; Graeff, C.; Trautmann, J.; Kraemer, M.; Zink, K.; Durante, M.; Bert, C.

2014-01-01

Purpose: Particle therapy (PT) has advantages over photon irradiation on static tumors. An increased biological effectiveness and active target conformal dose shaping are strong arguments for PT. However, the sensitivity to changes of internal geometry complicates the use of PT for moving organs. In case of interfractionally moving objects adaptive radiotherapy (ART) concepts known from intensity modulated radiotherapy (IMRT) can be adopted for PT treatments. One ART strategy is to optimize a new treatment plan based on daily image data directly before a radiation fraction is delivered [treatment replanning (TRP)]. Optimizing treatment plans for PT using a scanned beam is a time consuming problem especially for particles other than protons where the biological effective dose has to be calculated. For the purpose of TRP, fast optimization and fast dose calculation have been implemented into the GSI in-house treatment planning system (TPS) TRiP98. Methods: This work reports about the outcome of a code analysis that resulted in optimization of the calculation processes as well as implementation of routines supporting parallel execution of the code. To benchmark the new features, the calculation time for therapy treatment planning has been studied. Results: Compared to the original version of the TPS, calculation times for treatment planning (optimization and dose calculation) have been improved by a factor of 10 with code optimization. The parallelization of the TPS resulted in a speedup factor of 12 and 5.5 for the original version and the code optimized version, respectively. Hence the total speedup of the new implementation of the authors' TPS yielded speedup factors up to 55. Conclusions: The improved TPS is capable of completing treatment planning for ion beam therapy of a prostate irradiation considering organs at risk in this has been overseen in the review process. Also see below 6 min

The effect of plasma parameter on the bootstrap current of fast ions in neutral beam injection

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Cao Jinjia; Yang Lei

2014-01-01

The effect of plasma parameters on the distribution of net current density of fast ions produced by neutral beam injection is investigated in a large-aspect-ratio Tokamak with circular cross-section under specific parameters. Numerical results show that the value of net current density increases with the temperature of plasma increasing and decreases with the density of plasma increasing. The value of net current density is weakly affected by the effective charge number, but the peak of net current density moves towards edge plasma with effective charge number increasing. (authors)

Dosimetry and radiobiology of negative pions and heavy ions

International Nuclear Information System (INIS)

Raju, M.R.

1978-01-01

The depth dose distribution of pion beams has not been found superior to protons. Pion radiation quality at the plateau region is comparable to conventional low-LET radiations, and radiobiology results also indicate RBE values close to unity. In the pion stopping region, the radiation quality increases considerably. Radiobiology data for negative pions at the Bragg peak position clearly indicate the increase in RBE and the reduction in OER. Even at the Bragg peak position, compared to fast neutrons, the average LET of negative pions is lower. Pion radiobiology data have indicated lower RBE values and higher OER values compared to fast neutrons. The radiation quality of fast neutrons is in between that of carbon and neon ions at the peak region and that of neon ions at the plateau is lower than for fast neutrons. The mean LET value for helium ions, even at the distal end of the peak, is lower than for fast neutrons. Dose localization of heavy ions has been found to decrease slowly with increasing charge of the heavy ion. The intercellular contact that protects cells after exposure to low-LET radiations is not detected after exposure to heavy ions. Single and fractionated doses of heavy ions produce dose-response curves for heavy ions having reduced shoulders but similar slopes when compared to gamma rays. Fractionated treatments of heavy ions produce an enhanced effect in the peak region compared to the plateau region and could lead to a substantial gain in therapeutic ratio. The OER for protons was similar to that for x rays. The OER values for negative pions, helium ions, and carbon ions were larger, for neon ions similar, and for argon ions smaller when compared to fast neutrons.Negative pions, helium ions, and carbon ions may be very effective clinically because the radiation quality of these beams is similar to that of the mixed scheme of neutrons and x rays

Recent recoil ion momentum spectroscopy experiments at KSU

International Nuclear Information System (INIS)

Abdallah, M.; Cocke, C.L.; Kravis, S.; Montenegro, E.C.; Moshammer, R.; Saleh, L.; Ullrich, J.; Varghese, S.L.; Wolff, W.; Wolf, H.

1997-01-01

Recoil momentum spectroscopy is used to study collisions involving both fast and slow projectiles on He targets. Experiments have been performed on electron capture and loss from fast ions from the KSU LINAC and slow ions from the KSU CRYEBIS using a supersonic jets with a momentum resolution below 0.5 au. Using fast ions, the final states populated in electron capture from He by 10 MeV F 8+ have been resolved with a Q-value resolution of 18 eV, sufficient to separate final channels in which the He + ion is left excited from those in which He + is left in its ground state. With slow ions, electron capture from He by slow bare Ne ions has been studied. A few recent results are discussed. copyright 1997 American Institute of Physics

Turbulent transport of energetic ions

International Nuclear Information System (INIS)

Dannert, Tilman; Hauff, Thilo; Jenko, Frank; Guenter, Sibylle

2006-01-01

Approaching ITER operation, the issue of anomalous transport of fast particles becomes more and more important. This is partly because the ITER heating and current drive system relies heavily on neutral beam injection. Moreover burning plasmas are heated by fast fusion α particles.Fusion α particles are characterised by a fixed energy and an isotropic velocity distribution. Therefore they have gyroradii one magnitude larger than the thermal ions. The dependency of the particle diffusion of α test particles on the Kubo number K = VExBτc/λc (VExB mean E x B velocity, τc, λc correlation time and length of the turbulent potential) is presented. For different turbulent regimes, different dependency of the diffusion on the gyroradius is found. For large Kubo numbers, the transport is found to remain constant for gyroradii up to the correlation length of the potential, whereas it is drastically reduced in the small Kubo number regime.In the second part, a model for beam ions injected along the equilibrium magnetic field is described. The beam ions are treated gyrokinetically in a self-consistent way with the equilibrium distribution function taken as a shifted Maxwellian. The implications of such a model for the Vlasov equation, the field equations, and the calculation of moments and fluxes are discussed. Linear and nonlinear results, obtained with the gyrokinetic flux tube code GENE show the existence of a new instability driven by fast beam ions. The instability has a maximum growth rate at perpendicular wave numbers of kyρs ∼ 0.15 and depends mainly on the beam velocity and the density gradient of the beam ions. This instability leads to a replacement of bulk ion particle transport by fast ion particle transport, connected to a strongly enhanced heat flux. In the presence of this instability, the turbulent particle and heat transport is dominated by fast ions

Effects of fast ions and an external inductive electric field on the neoclassical parallel flow, current, and rotation in general toroidal systems

International Nuclear Information System (INIS)

Nakajima, Noriyoshi; Okamoto, Masao.

1992-05-01

Effects of external momentum sources, i.e., fast ions produced by the neutral beam injection and an external inductive electric field, on the neoclassical ion parallel flow, current, and rotation are analytically investigated for a simple plasma in general toroidal systems. It is shown that the contribution of the external sources to the ion parallel flow becomes large as the collision frequency of thermal ions increases because of the momentum conservation of Coulomb collisions and sharply decreasing viscosity coefficients, with collision frequency. As a result, the beam-driven parallel flow of thermal ions becomes comparable to that of electrons in the Pfirsh-Schluter collisionality regime, whereas in the 1/μ or banana regime it is smaller than that of electrons by the order of √(m e /m i ) (m e and m i are electron and ion masses). This beam-driven ion parallel flow can not produce a large beam-driven current because of the cancellation with electron parallel flow, but produces a large toroidal rotation of ions. As both electrons and ions approach the Pfirsh-Schluter collisionality regime the contribution of thermodynamical forces becomes negligibly small and the large toroidal rotation of ions is predominated by the beam-driven component in the non-axisymmetric configuration with large helical ripples. (author)

Development and testing of a fast digital electronic system for ion identification and spectroscopy

International Nuclear Information System (INIS)

Legou, Th.

2002-02-01

This report deals with a fast digital electronic system developed for ion identification and spectroscopy. The system, called IRIS, has been conceived for the super heavy element research program: FUSION. In order to observe a super heavy element, the energy of the compound nucleus implanted in a silicon detector must be measured, and the alpha decay also registered. The associated electronics must therefore handle a very wide range of energies and also exhibit a small recovery time after the implantation of the compound nucleus. IRIS is connected to the output of a charge preamplifier. It digitizes the signal and then executes two digital signal processes: the first to detect the particle, and the second to determine the energy deposited in the silicon detector. The use of programmed processing allows for the adjustment of the digital processing parameters, as well as a choice of other digital signal processing procedures, depending the application. After having explained why a conventional electronic system cannot be used for the detection of super-heavy ions, IRIS' structure is detailed and a number of digital signal processing procedures are studied and tested. (author)

Isomeric signatures in the fragmentation of pyridazine and pyrimidine induced by fast ion impact

Energy Technology Data Exchange (ETDEWEB)

Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Montenegro, Eduardo C. [Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, RJ (Brazil)

2015-07-28

We present fast proton impact induced fragmentations of pyrimidine and pyridazine as an experimental resource to investigate isomeric signatures. Major isomeric imprints are identified for few fragment ions and differences of more than an order of magnitude for the cross sections of fragments of the same mass were measured. The observation of the molecular structure of these isomers gives no apparent indication for the reasons for such substantial differences. It is verified that the simple displacement of the position of one nitrogen atom strongly inhibits or favors the production of some ionic fragment species. The dependency of the fragmentation cross sections on the proton impact energy, investigated by means of time of flight mass spectroscopy and of a model calculation based in first order perturbation theory, allows us to disentangle the complex collision dynamics of the ionic fragments. The proton-induced fragmentation discriminates rather directly the association between a molecular orbital ionization and the fragment-ions creation and abundance, as well as how the redistribution of the energy imparted to the molecules takes place, triggering not only single but also double vacancy and leads to specific fragmentation pathways.

A novel ion cooling trap for multi-reflection time-of-flight mass spectrograph

Energy Technology Data Exchange (ETDEWEB)

Ito, Y., E-mail: yito@riken.jp [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Schury, P. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States); Wada, M.; Naimi, S. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Smorra, C. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Sonoda, T. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mita, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Takamine, A. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aoyama Gakuin University, 4-4-25 Shibuya, Shibuya-ku, Tokyo 150-8366 (Japan); Okada, K. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan); Ozawa, A. [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Wollnik, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States)

2013-12-15

Highlights: • Fast cooling time: 2 ms. • High efficiency: ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +}. • 100% Duty cycle with double trap system. -- Abstract: A radiofrequency quadrupole ion trap system for use with a multi-reflection time-of-flight mass spectrograph (MRTOF) for short-lived nuclei has been developed. The trap system consists of two different parts, an asymmetric taper trap and a flat trap. The ions are cooled to a sufficient small bunch for precise mass measurement with MRTOF in only 2 ms cooling time in the flat trap, then orthogonally ejected to the MRTOF for mass analysis. A trapping efficiency of ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +} has been achieved.

Fast Neutral Pressure Measurements in NSTX

International Nuclear Information System (INIS)

R. Raman; H.W. Kugel; T. Provost; R. Gernhardt; T.R. Jarboe; M.G. Bell

2002-01-01

Several fast neutral pressure gauges have been installed on NSTX [National Spherical Torus Experiment] to measure the vessel and divertor pressure during inductive and coaxial helicity injected (CHI) plasma operations. Modified, PDX [Poloidal Divertor Experiment]-type Penning gauges have been installed on the upper and lower divertors. Neutral pressure measurements during plasma operations from these and from two shielded fast Micro ion gauges at different toroidal locations on the vessel mid-plane are described. A new unshielded ion gauge, referred to as the In-vessel Neutral Pressure (INP) gauge is under development

Characterization of graphite etched with potassium hydroxide and its application in fast-rechargeable lithium ion batteries

Science.gov (United States)

Shim, Jae-Hyun; Lee, Sanghun

2016-08-01

Surface-modified graphite for application as an anode material in lithium ion batteries was obtained by etching with KOH under mild conditions without high-temperature annealing. The surface of the etched graphite is covered with many nano-sized pores that act as entrances for lithium ions during the charging process. As compared with pristine graphite and other references such as pitch-coated or etched graphite samples with annealing, our non-annealed etched graphite exhibits excellent electrochemical properties, particularly at fast charging rates of over 2.5 C. While avoidance of the trade-off between increase of irreversible capacity and good rate capability has previously been a main concern in highly porous carbonaceous materials, we show that the slightly larger surface area created by the etching does not induce a significant increase of irreversible capacity. This study shows that it is important to limit the size of pores to the nanometer scale for excellent battery performance, which is possible by etching under relatively mild conditions.

Main Design Principles of the Cold Beam Pipe in the FastRamped Superconducting Accelerator Magnets for Heavy Ion Synchrotron SIS100

Science.gov (United States)

Mierau, A.; Schnizer, P.; Fischer, E.; Macavei, J.; Wilfert, S.; Koch, S.; Weiland, T.; Kurnishov, R.; Shcherbakov, P.

SIS100, the world second large scale heavy ion synchrotron using fast ramped superconducting magnets, is to be built at FAIR. Its high current operation of intermediate charge state ions requires stable vacuum pressures technological feasible design solutions, three opposite requirements have to be met: minimum magnetic field distortion caused by AC losses, mechanical stability and low and stable wall temperatures of the beam pipe. We present the possible design versions of the beam pipe for the high current curved dipole. The pros and cons of these proposed designs were studied using simplified analytical models, FEM calculations and tests on models.

Ion sources in AMS

International Nuclear Information System (INIS)

Iyer, Indira S.

1997-01-01

Accelerator Mass Spectrometry (AMS) entails the sputtering of various samples in an ion source followed by high precision mass analysis of the sputtered ion species in a Tandem Electrostatic Accelerator. A brief account is given

Amorphous Fast Ion Conducting Systems, Part 1. Structure and Properties of Mid and Far IR Transmitting Materials, Part 2

Science.gov (United States)

1991-10-31

Glasses with high conductivities can also be formed with the Lewis acids GeO 2 (11 ) and no doubt Bi 20 3, TeO2 , etc., but these have been less...P age 3 1. Mechanical Relaxation and Relation to Electrical Relaxation in Fast Ion-Conducting Glasses ...relaxation although considerable information was available for the classical alkali silicate and borate glasses . Our program was to utilize the rheovibron

Ion-electron recombination in merged-beams experiments

International Nuclear Information System (INIS)

Schmidt, H.T.

1994-01-01

In the present thesis, studies of recombination processes applying the technique of merged beams of fast ions and electrons are described. The main advantage of this technique is that the low relative velocity of ions and electrons necessary for these investigations can be achieved, at the same time as the velocity of the ions relative to the molecules of the residual gas is high. The high ion velocity leads to a very low reaction cross section for the leading contribution to the background signal, the capture of electrons in collisions with residual gas molecules. The experimental technique is described, emphasizing the electron beam velocity distribution and its relation to the energy resolution of the experiments. The presentation of the process of electron cooling is aimed at introducing this process as a tool for merged-beams experiments in storage rings rather than investigating the process itself. The non-resonant process of radiative recombination for non-fully stripped ions, showing evidence of incomplete screening is presented. Experimental investigation of dielectronic recombination is presented. Results of measurements of this process for He-like ions form the Aarhus single-pass experiment and the Heidelberg storage ring experiment are compared. Recombination is reduced from being the aim of the investigation to being a tool for high-precision measurements of the lifetimes of the 1s2s 3 S metastable states of HE-like ions of boron, carbon, and nitrogen, performed at the Heidelberg storage ring. The experiment is concerned with the process of dissociative recombination of molecular hydrogen ions. The discussion of this experiment emphasizes the distribution of population on the different vibrational levels of the ions in the initial state. In particular, a laser photo-dissociation technique was introduced to reduce the number of initial levels in the experiment. (EG) 24 refs

Asprosin, a fasting-induced glucogenic protein hormone

Science.gov (United States)

Hepatic glucose release into the circulation is vital for brain function and survival during periods of fasting and is modulated by an array of hormones that precisely regulate plasma glucose levels. We have identified a fasting-induced protein hormone that modulates hepatic glucose release. It is t...