Trapped-ion quantum logic gates based on oscillating magnetic fields

Science.gov (United States)

Ospelkaus, Christian; Langer, Christopher E.; Amini, Jason M.; Brown, Kenton R.; Leibfried, Dietrich; Wineland, David J.

2009-05-01

Oscillating magnetic fields and field gradients can be used to implement single-qubit rotations and entangling multiqubit quantum gates for trapped-ion quantum information processing. With fields generated by currents in microfabricated surface-electrode traps, it should be possible to achieve gate speeds that are comparable to those of optically induced gates for realistic distances between the ions and the electrode surface. Magnetic-field-mediated gates have the potential to significantly reduce the overhead in laser-beam control and motional-state initialization compared to current QIP experiments with trapped ions and will eliminate spontaneous scattering decoherence, a fundamental source of decoherence in laser-mediated gates. A potentially beneficial environment for the implementation of such schemes is a cryogenic ion trap, because small length scale traps with low motional heating rates can be realized. A cryogenic ion trap experiment is currently under construction at NIST.

Trapped-ion quantum logic gates based on oscillating magnetic fields.

Science.gov (United States)

Ospelkaus, C; Langer, C E; Amini, J M; Brown, K R; Leibfried, D; Wineland, D J

2008-08-29

Oscillating magnetic fields and field gradients can be used to implement single-qubit rotations and entangling multiqubit quantum gates for trapped-ion quantum information processing (QIP). With fields generated by currents in microfabricated surface-electrode traps, it should be possible to achieve gate speeds that are comparable to those of optically induced gates for realistic distances between the ion crystal and the electrode surface. Magnetic-field-mediated gates have the potential to significantly reduce the overhead in laser-beam control and motional-state initialization compared to current QIP experiments with trapped ions and will eliminate spontaneous scattering, a fundamental source of decoherence in laser-mediated gates.

Quantum Information Experiments with Trapped Ions at NIST

Science.gov (United States)

Wilson, Andrew

2015-03-01

We present an overview of recent trapped-ion quantum information experiments at NIST. Advancing beyond few-qubit ``proof-of-principle'' experiments to the many-qubit systems needed for practical quantum simulation and information processing, without compromising on the performance demonstrated with small systems, remains a major challenge. One approach to scalable hardware development is surface-electrode traps. Micro-fabricated planar traps can have a number of useful features, including flexible electrode geometries, integrated microwave delivery, and spatio-temporal tuning of potentials for ion transport and spin-spin interactions. In this talk we report on a number of on-going investigations with surface traps. Experiments feature a multi-zone trap with closely spaced ions in a triangular arrangement (a first step towards 2D arrays of ions with tunable spin-spin interactions), a scheme for smooth transport through a junction in a 2D structure based on switchable RF potentials, and a micro-fabricated photo-detector integrated into a trap. We also give a progress report on our latest efforts to improve the fidelity of both optical and microwave 2-qubit gates. This work was supported by IARPA, ONR and the NIST Quantum Information Program. The 3-ion and switchable-RF-junction traps were developed in collaboration with Sandia National Laboratory.

Ion Trapping, Storage, and Ejection in Structures for Lossless Ion Manipulations.

Science.gov (United States)

Zhang, Xinyu; Garimella, Sandilya V B; Prost, Spencer A; Webb, Ian K; Chen, Tsung-Chi; Tang, Keqi; Tolmachev, Aleksey V; Norheim, Randolph V; Baker, Erin S; Anderson, Gordon A; Ibrahim, Yehia M; Smith, Richard D

2015-06-16

A new Structures for Lossless Ion Manipulations (SLIM) module, having electrode arrays patterned on a pair of parallel printed circuit boards (PCB), was constructed and utilized to investigate capabilities for ion trapping at a pressure of 4 Torr. Positive ions were confined by application of RF voltages to a series of inner rung electrodes with alternating phase on adjacent electrodes, in conjunction with positive DC potentials on surrounding guard electrodes on each PCB. An axial DC field was also introduced by stepwise varying the DC potentials applied to the inner rung electrodes to control the ion transport and accumulation inside the ion trapping region. We show that ions can be trapped and accumulated with up to 100% efficiency, stored for at least 5 h with no significant losses, and then could be rapidly ejected from the SLIM trap. The present results provide a foundation for the development of much more complex SLIM devices that facilitate extended ion manipulations.

Chemical characterization of microparticles by laser ablation in an ion trap mass spectrometer

International Nuclear Information System (INIS)

Dale, J.M.; Whitten, W.B.; Ramsey, J.M.

1991-01-01

We are developing a new technique for the chemical characterization of microparticles based upon the use of electrodynamic traps. The electrodynamic trap has achieved widespread use in the mass spectrometry community in the form of the ion trap mass spectrometer or quadrupole ion trap. Small macroscopic particles can be confined or leviated within the electrode structure of a three-dimensional quadrupole electrodynamic trap in the same way as fundamental charges or molecular ions by using a combination of ac and dc potentials. Our concept is to use the same electrode structure to perform both microparticle levitation and ion trapping/mass analysis. The microparticle will first be trapped and spatially stabilized within the trap for characterization by optical probes, i.e., absorption, fluorescence, or Raman spectroscopy. After the particle has been optically characterized, it is further characterized using mass spectrometry. Ions are generated from the particle surface using laser ablation or desorption. The characteristics of the applied voltages are changed to trap the ions formed by the laser with the ions subsequently mass analyzed. The work described in this paper focuses on the ability to perform laser desorption experiments on microparticles contained within the ion trap. Laser desorption has previously been demonstrated in ion trap devices by applying the sample to a probe which is inserted so as to place the sample at the surface of the ring electrode. Our technique requires the placement of a microparticle in the center of the trap. Our initial experiments have been performed on falling microparticles rather than levitated particles to eliminate voltage switching requirements when changing from particle to ion trapping modes

Achieving Translationally Invariant Trapped Ion Rings

Science.gov (United States)

Urban, Erik; Li, Hao-Kun; Noel, Crystal; Hemmerling, Boerge; Zhang, Xiang; Haeffner, Hartmut

2017-04-01

We present the design and implementation of a novel surface ion trap design in a ring configuration. By eliminating the need for wire bonds through the use of electrical vias and using a rotationally invariant electrode configuration, we have realized a trap that is able to trap up to 20 ions in a ring geometry 45um in diameter, 400um above the trap surface. This large trapping height to ring diameter ratio allows for global addressing of the ring with both lasers and electric fields in the chamber, thereby increasing our ability to control the ring as a whole. Applying compensating electric fields, we measure very low tangential trap frequencies (less than 20kHz) corresponding to rotational barriers down to 4mK. This measurement is currently limited by the temperature of the ions but extrapolation indicates the barrier can be reduced much further with more advanced cooling techniques. Finally, we show that we are able to reduce this energy barrier sufficiently such that the ions are able to overcome it either through thermal motion or rotational motion and delocalize over the full extent of the ring. This work was funded by the Keck Foundation and the NSF.

Novel Ion Trap Design for Strong Ion-Cavity Coupling

Directory of Open Access Journals (Sweden)

Alejandro Márquez Seco

2016-04-01

Full Text Available We present a novel ion trap design which facilitates the integration of an optical fiber cavity into the trap structure. The optical fibers are confined inside hollow electrodes in such a way that tight shielding and free movement of the fibers are simultaneously achievable. The latter enables in situ optimization of the overlap between the trapped ions and the cavity field. Through numerical simulations, we systematically analyze the effects of the electrode geometry on the trapping characteristics such as trap depths, secular frequencies and the optical access angle. Additionally, we simulate the effects of the presence of the fibers and confirm the robustness of the trapping potential. Based on these simulations and other technical considerations, we devise a practical trap configuration that isviable to achieve strong coupling of a single ion.

Stability and delayed fragmentation of highly charged C60 trapped in a conic-electrode electrostatic ion resonator (ConeTrap)

International Nuclear Information System (INIS)

Bernard, J.; Wei, B.; Bourgey, A.; Bredy, R.; Chen, L.; Kerleroux, M.; Martin, S.; Montagne, G.; Salmoun, A.; Terpend-Ordaciere, B.

2007-01-01

We employed a conic-electrode electrostatic ion resonator (ConeTrap) to store the recoil ions (C 60 r+ ) resulting from collision between 56keV Ar 8+ ions and C 60 in order to study their stability over a long time range (several milliseconds). The originality of our method, based on the trapping of a single ion to preserve the detection in coincidence of all the products of the collision, is presented in detail. Our results show that C 60 ions produced in such collisions are stable in the considered observation time. By employing the ConeTrap as a secondary mass spectrometer in order to let the ions oscillate only for a single period, we have been able to observe delayed evaporation of cold C 60 3+ ions 20μs after the collision. We interpret quantitatively the relative yields of daughter ions with a cascade model in which the transition rates are estimated via the commonly used Arrhenius law, taking into account the contribution of the radiative decay

Chemical characterization of microparticles by laser ablation in an ion trap mass spectrometer

International Nuclear Information System (INIS)

Dale, J.M.; Whitten, W.B.; Ramsey, J.M.

1991-01-01

We are developing a new technique for the chemical characterization of microparticles based upon the use of electrodynamic traps. The electrodynamic trap has achieved widespread use in the mass spectrometry community in the form of the ion trap mass spectrometer or quadrupole ion trap. Small macroscopic particles can be confined or levitated within the electrode structure of a three-dimensional quadrupole electrodynamic trap in the same way as fundamental charges or molecular ions by using a combination of ac and dc potentials. Our concept is to use the same electrode structure to perform both microparticle levitation and ion trapping/mass analysis. The microparticle will first be trapped and spatially stabilized within the trap for characterization by optical probes, i.e., absorption, fluorescence, or Raman spectroscopy. After the particle has been optically characterized, it is further characterized using mass spectrometry. Ions are generated from the particle surface using laser ablation or desorption. The characteristics of the applied voltages are changed to trap the ions formed by the laser with the ions subsequently mass analyzed. The work described in this paper focuses on the ability to perform laser desorption experiments on microparticles contained within the ion trap

Note: Ion source design for ion trap systems

Science.gov (United States)

Noriega, J. R.; Quevedo, M.; Gnade, B.; Vasselli, J.

2013-06-01

A small plasma (glow discharge) based ion source and circuit are described in this work. The ion source works by producing a high voltage pulsed discharge between two electrodes in a pressure range of 50-100 mTorr. A third mesh electrode is used for ion extraction. The electrodes are small stainless steel screws mounted in a MACOR ionization chamber in a linear arrangement. The electrode arrangement is driven by a circuit, design for low power operation. This design is a proof of concept intended for applications on small cylindrical ion traps.

Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation

International Nuclear Information System (INIS)

Charles Doret, S; Amini, Jason M; Wright, Kenneth; Volin, Curtis; Killian, Tyler; Ozakin, Arkadas; Denison, Douglas; Hayden, Harley; Pai, C-S; Slusher, Richart E; Harter, Alexa W

2012-01-01

Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled dc electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on dc electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains. (paper)

Mini ion trap mass spectrometer

Science.gov (United States)

Dietrich, D.D.; Keville, R.F.

1995-09-19

An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

Understanding interaction of curcumin and metal ions on electrode surfaces using EDXRF

Science.gov (United States)

Joseph, Daisy; Kumar, K. Krishna; Narayanan, S. Sriman

2018-04-01

A chemically modified electrode was developed for determination of metal ions (Cd, Pb, Zn, Co, Hg). The modifier used for the study was Curcumin. Curcumin acts as a complexing agent at the surface of the electrode for preconcentration of metal ions from electrolyte to electrode surface and stripped back to electrolyte during analysis. EDXRF was used to analyze these electrodes and it was concluded that the PCR modified electrode favored effective chelation for lead and mercury.

Active stabilization of ion trap radiofrequency potentials

Energy Technology Data Exchange (ETDEWEB)

Johnson, K. G.; Wong-Campos, J. D.; Restelli, A.; Landsman, K. A.; Neyenhuis, B.; Mizrahi, J.; Monroe, C. [Joint Quantum Institute and University of Maryland Department of Physics, College Park, Maryland 20742 (United States)

2016-05-15

We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a radiofrequency (rf) Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1 MHz atomic oscillation frequency to be better than 10 Hz or 10 ppm. This represents a suppression of ambient noise on the rf circuit by 34 dB. This technique could impact the sensitivity of ion trap mass spectrometry and the fidelity of quantum operations in ion trap quantum information applications.

Optimization and simulation of MEMS rectilinear ion trap

Directory of Open Access Journals (Sweden)

Huang Gang

2015-04-01

Full Text Available In this paper, the design of a MEMS rectilinear ion trap was optimized under simulated conditions. The size range of the MEMS rectilinear ion trap’s electrodes studied in this paper is measured at micron scale. SIMION software was used to simulate the MEMS rectilinear ion trap with different sizes and different radio-frequency signals. The ion-trapping efficiencies of the ion trap under these different simulation conditions were obtained. The ion-trapping efficiencies were compared to determine the performance of the MEMS rectilinear ion trap in different conditions and to find the optimum conditions. The simulation results show that for the ion trap at micron scale or smaller, the optimized length–width ratio was 0.8, and a higher frequency of radio-frequency signal is necessary to obtain a higher ion-trapping efficiency. These results have a guiding role in the process of developing MEMS rectilinear ion traps, and great application prospects in the research fields of the MEMS rectilinear ion trap and the MEMS mass spectrometer.

Trapped atomic ions for quantum-limited metrology

Science.gov (United States)

Wineland, David

2017-04-01

Laser-beam-manipulated trapped ions are a candidate for large-scale quantum information processing and quantum simulation but the basic techniques used can also be applied to quantum-limited metrology and sensing. Some examples being explored at NIST are: 1) As charged harmonic oscillators, trapped ions can be used to sense electric fields; this can be used to characterize the electrode-surface-based noisy electric fields that compromise logic-gate fidelities and may eventually be used as a tool in surface science. 2) Since typical qubit logic gates depend on state-dependent forces, we can adapt the gate dynamics to sensitively detect additional forces. 3) We can use extensions of Bell inequality measurements to further restrict the degree of local realism possessed by Bell states. 4) We also briefly describe experiments for creation of Bell states using Hilbert space engineering. This work is a joint effort including the Ion-Storage group, the Quantum processing group, and the Computing and Communications Theory group at NIST, Boulder. Supported by IARPA, ONR, and the NIST Quantum Information Program.

Surface modification of positive electrode materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Julien, C.M., E-mail: Christian.Julien@upmc.fr [Sorbonne Universités, UPMC Univ. Paris 6, Physicochimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), UMR 8234, 75005 Paris (France); Mauger, A. [Institut de Minéralogie de Physique des Matériaux et de Cosmochimie (IMPMC), UPMC Univ. Paris 6, 4 place Jussieu, 75005 Paris (France); Groult, H. [Sorbonne Universités, UPMC Univ. Paris 6, Physicochimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), UMR 8234, 75005 Paris (France); Zaghib, K. [Energy Storage and Conversion, Research Institute of Hydro-Québec, Varennes, Québec J3X 1S1 (Canada)

2014-12-01

The advanced lithium-ion batteries are critically important for a wide range of applications, from portable electronics to electric vehicles. The research on their electrodes aims to increase the energy density and the power density, improve the calendar and the cycling life, without sacrificing the safety issues. A constant progress through the years has been obtained owing to the surface treatment of the particles, in particular the coating of the nanoparticles with a layer that protects the core region from side reactions with the electrolyte, prevents the loss of oxygen, and the dissolution of the metal ions in the electrolyte, or simply improve the conductivity of the powder. The purpose of the present work is to present the different surface modifications that have been tried for three families of positive electrodes: layered, spinel and olivine frameworks that are currently considered as promising materials. The role of the different coats used to improve either the surface conductivity, or the thermal stability, or the structural integrity is discussed. - Highlights: • Report the various surface modifications tried for the positive electrodes of Li-ion batteries. • The role of different coats used to improve the conductivity, or the thermal stability, or the structural integrity. • Improvement of electrochemical properties of electrodes after coating or surface treatment.

The electrochemical behavior and surface structure of titanium electrodes modified by ion beams

International Nuclear Information System (INIS)

Huang, G.F.; Xie, Z.; Huang, W.Q.; Yang, S.B.; Zhao, L.H.

2004-01-01

Industrial grade titanium modified by ion implantation and sputtering was used as electrodes. The effect of ion beam modification on the electrochemical behavior and surface structure of electrodes was investigated. Also discussed is the hydrogen evolution process of the electrode in acidic solution. Several ions such as Fe + , C + , W + , Ni + and others, were implanted into the electrode. The electrochemical tests were carried out in 1N H 2 SO 4 solution at 30±1 deg. C. The electrode potential was measured versus a saturate calomel electrode as a function of immersion time. The cathodic polarization curves were measured by the stable potential static method. The surface layer composition and the chemical state of the electrodes were also investigated by Auger electron spectrometer (AES) and X-ray photoelectron spectroscopy (XPS) technique. The results show that: (1) the stability of modified electrodes depends on the active elements introduced by ion implantation and sputtering deposition. (2) The hydrogen evolution activity of industrial grade titanium may be improved greatly by ion beam modification. (3) Ion beam modification changed the composition and the surface state of electrodes over a certain depth range and forms an activity layer having catalytic hydrogen evolution, which inhibited the absorption of hydrogen and formation of titanium hydride. Thus promoted hydrogen evolution and improved the hydrogen evolution catalytic activity in industrial grade titanium

Technology for On-Chip Qubit Control with Microfabricated Surface Ion Traps

Energy Technology Data Exchange (ETDEWEB)

Highstrete, Clark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Quantum Information Sciences Dept.; Scott, Sean Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). RF/Optoelectronics Dept.; Nordquist, Christopher D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). RF/Optoelectronics Dept.; Sterk, Jonathan David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photonic Microsystem Technologies Dept.; Maunz, Peter Lukas Wilhelm [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photonic Microsystem Technologies Dept.; Tigges, Christopher P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photonic Microsystem Technologies Dept.; Blain, Matthew Glenn [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photonic Microsystem Technologies Dept.; Heller, Edwin J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Microsystems Integration Dept.; Stevens, James E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). MESAFab Operations 2 Dept.

2013-11-01

Trapped atomic ions are a leading physical system for quantum information processing. However, scalability and operational fidelity remain limiting technical issues often associated with optical qubit control. One promising approach is to develop on-chip microwave electronic control of ion qubits based on the atomic hyperfine interaction. This project developed expertise and capabilities at Sandia toward on-chip electronic qubit control in a scalable architecture. The project developed a foundation of laboratory capabilities, including trapping the ¹⁷¹Yb⁺ hyperfine ion qubit and developing an experimental microwave coherent control capability. Additionally, the project investigated the integration of microwave device elements with surface ion traps utilizing Sandia’s state-of-the-art MEMS microfabrication processing. This effort culminated in a device design for a multi-purpose ion trap experimental platform for investigating on-chip microwave qubit control, laying the groundwork for further funded R&D to develop on-chip microwave qubit control in an architecture that is suitable to engineering development.

Cryogenic setup for trapped ion quantum computing.

Science.gov (United States)

Brandl, M F; van Mourik, M W; Postler, L; Nolf, A; Lakhmanskiy, K; Paiva, R R; Möller, S; Daniilidis, N; Häffner, H; Kaushal, V; Ruster, T; Warschburger, C; Kaufmann, H; Poschinger, U G; Schmidt-Kaler, F; Schindler, P; Monz, T; Blatt, R

2016-11-01

We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with 40 Ca + and 88 Sr + ions. The instability of the laser manipulating the optical qubits in 40 Ca + is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10 -15 at 0.33 s. To evaluate the performance of the apparatus, we trapped 40 Ca + ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.

Ion trapping in the high-energy storage ring HESR

Energy Technology Data Exchange (ETDEWEB)

Hinterberger, Frank [Bonn Univ. (Germany). Helmholtz-Institut fuer Strahlen- und Kernphysik

2011-10-15

The problem of ion trapping in the high-energy storage ring HESR is studied in the present report. Positive ions are trapped in the negative potential well of the antiproton beam. The ions are produced by the interaction between the antiproton beam and the residual gas. The adverse effects of ion trapping like tune shifts, tune spreads and coherent instabilities are reviewed. The ion production rate by ionization of the residual gas molecules is estimated. The negative potential well and the corresponding electric fields of the antiproton beam are evaluated in order to study the transverse and longitudinal motion of the ions and the accumulation in trapping pockets. The removal of ions can be achieved using clearing electrodes and under certain conditions resonant transverse beam shaking. Diagnostic tools and measurements of trapped ion effects are sketched. (orig.)

Cooling the Collective Motion of Trapped Ions to Initialize a Quantum Register

Science.gov (United States)

2016-09-13

similar to that described in Ref . [6]. The electrodes in this trap are made from 125-mm-thick sheets of Be metal, as shown in Fig. 1. We apply a po...tential fstd ­ V0 cossVT td 1 U0 to the (elliptical) ring electrode relative to the end cap electrodes. If several ions are trapped and cooled, they...previously been observed in single ions [5,10,13]; in Ref . [5], the heating drove the ion out of the motional (COM) ground state in approximately 1 ms. We

Preliminary Tests of a Paul ion Trap as an Ion Source

Science.gov (United States)

Sadat Kiai, S. M.; Zirak, A. R.; Elahi, M.; Adlparvar, S.; Mortazavi, B. N.; Safarien, A.; Farhangi, S.; Sheibani, S.; Alhooie, S.; Khalaj, M. M. A.; Dabirzadeh, A. A.; Ruzbehani, M.; Zahedi, F.

2010-10-01

The paper reports on the design and construction of a Paul ion trap as an ion source by using an impact electron ionization technique. Ions are produced in the trap and confined for the specific time which is then extracted and detected by a Faraday cup. Especial electronic configurations are employed between the end caps, ring electrodes, electron gun and a negative voltage for the detector. This configuration allows a constant low level of pure ion source between the pulsed confined ion sources. The present experimental results are based on the production and confinement of Argon ions with good stability and repeatability, but in principle, the technique can be used for various Argon like ions.

Direct trace analysis of metals and alloys in a quadrupole ion-trap mass spectrometer

CERN Document Server

Song, K S; Yang, M; Cha, H K; Lee, J M; Lee, G H

1999-01-01

An ion-trap mass spectrometer adopting a quadrupole ion-trap and laser ablation/ionization method was constructed. The developed system was tested for composition analysis of some metals (Cu, stainless), and alloys (hastalloy C, mumetal) by mass spectrometry. Samples were analyzed by using laser ablation from a sample probe tip followed by a mass analysis with the quadrupole ion-trap. The quadrupole ion-trap was modified to enable laser ablation by a XeCl excimer laser pulse that passed radially through the ring electrode. A mass scan of the produced ions was performed in the mass selective instability mode wherein trapped ions were successively detected by increasing the rf voltage through the ring electrode. Factors affecting the mass resolution, such as pressure of buffer gas and ablation laser power, are discussed.

Ring-shaped Wigner crystals of trapped ions at the micronscale

Science.gov (United States)

Li, Haokun; Urban, Erik; Noel, Crystal; Chuang, Alexander; Xia, Yang; Hemmerling, Borge; Wang, Yuan; Zhang, Xiang; Haeffner, Hartmut

Trapped ion crystals are ideal platforms to study many-body physics and quantum information processing, with both the internal electronic states and external motional degree-of-freedoms controllable at the single quantum level. In contrast to conventional, finite, linear chains of ions, a ring topology exhibiting periodic boundary conditions and rotational symmetry opens up a new directions to diverse topics. However, previous implementations of ion rings result in small aspect ratios (electrode distance to ring diameter, making the rotational symmetry of the ion crystals prone to stray electric fields from imperfections of the trap electrodes, particularly evident at low temperatures. Here, using a new trap design with a 60-fold improvement of this aspect ratio, we demonstrate crystallization of 40Ca+ ions in a ring with rotational energy barriers comparable to the thermal energy of Doppler laser cooled ion crystals. When further reducing the rotational energy barriers, we observe delocalization of the ion rings. With this result, we enter a regime where quantum topological effects can be studied and novel quantum computation and simulation experiments can be implemented.

A very large Paul trap system for in-line capture of high-energy DC radioactive ion beams

International Nuclear Information System (INIS)

Dezfuli, A.M. Ghalambor; Moore, R.B.; Varfalvy, P.; Schwarz, S.

2002-01-01

A very large Paul trap (VLPTRAP) has built to test in-flight collection of DC ion beams. An iterative design process led to a Paul trap that was basically a cylindrical electrode of internal diameter 120 mm with two symmetrically placed coaxial end electrodes that approximated hyperboloids of revolution separated by 106 mm. The trap was operated at up to 20 kV pp at 1 MHz on the ring cylindrical electrode relative to the end electrodes with buffer gas pressures up to 40 mPa. Ions were delivered to the trap from a 60 keV + Cs ion gun and electrostatically decelerated to about 100 eV for entrance. After a cooling time of the order of 1 ms, the ions were extracted by biasing the end electrodes. Beam pulses of less than 1 s could be extracted, at repetition rates down to 1 Hz. An overall bunching efficiency of about 0.4% was obtained, resulting from a collection efficiency of 2% and an extraction efficiency of 20%. The trap could hold up to 10 7 ions at a temperature of 1000 K

Sideband cooling and coherent dynamics in a microchip multi-segmented ion trap

Energy Technology Data Exchange (ETDEWEB)

Schulz, Stephan A; Poschinger, Ulrich; Ziesel, Frank; Schmidt-Kaler, Ferdinand [Universitaet Ulm, Institut fuer Quanteninformationsverarbeitung, Albert-Einstein-Allee 11, D-89069 Ulm (Germany)], E-mail: stephan.schulz@uni-ulm.de

2008-04-15

Miniaturized ion trap arrays with many trap segments present a promising architecture for scalable quantum information processing. The miniaturization of segmented linear Paul traps allows partitioning the microtrap into different storage and processing zones. The individual position control of many ions-each of them carrying qubit information in its long-lived electronic levels-by the external trap control voltages is important for the implementation of next generation large-scale quantum algorithms. We present a novel scalable microchip multi-segmented ion trap with two different adjacent zones, one for the storage and another dedicated to the processing of quantum information using single ions and linear ion crystals. A pair of radio-frequency-driven electrodes and 62 independently controlled dc electrodes allows shuttling of single ions or linear ion crystals with numerically designed axial potentials at axial and radial trap frequencies of a few megahertz. We characterize and optimize the microtrap using sideband spectroscopy on the narrow S{sub 1/2}{r_reversible}D{sub 5/2} qubit transition of the {sup 40}Ca{sup +} ion, and demonstrate coherent single-qubit Rabi rotations and optical cooling methods. We determine the heating rate using sideband cooling measurements to the vibrational ground state, which is necessary for subsequent two-qubit quantum logic operations. The applicability for scalable quantum information processing is proved.

Surface and interface sciences of Li-ion batteries. -Research progress in electrode-electrolyte interface-

Science.gov (United States)

Minato, Taketoshi; Abe, Takeshi

2017-12-01

The application potential of Li-ion batteries is growing as demand increases in different fields at various stages in energy systems, in addition to their conventional role as power sources for portable devices. In particular, applications in electric vehicles and renewable energy storage are increasing for Li-ion batteries. For these applications, improvements in battery performance are necessary. The Li-ion battery produces and stores electric power from the electrochemical redox reactions between the electrode materials. The interface between the electrodes and electrolyte strongly affects the battery performance because the charge transfer causing the electrode redox reaction begins at this interface. Understanding of the surface structure, electronic structure, and chemical reactions at the electrode-electrolyte interface is necessary to improve battery performance. However, the interface is located between the electrode and electrolyte materials, hindering the experimental analysis of the interface; thus, the physical properties and chemical processes have remained poorly understood until recently. Investigations of the physical properties and chemical processes at the interface have been performed using advanced surface science techniques. In this review, current knowledge and future research prospects regarding the electrode-electrolyte interface are described for the further development of Li-ion batteries.

Nested Penning Trap as a Source of Singly Charged Ions

International Nuclear Information System (INIS)

Ordonez, C.A.

2003-01-01

In the work reported, the possibility of using a nested Penning trap as a high purity source of low-charge-state ions is studied. For the configuration considered, a relatively dense ion plasma is confined by a three-dimensional electric potential well. The three-dimensional well is produced by the electric field generated by both the trap electrodes and a trapped electron plasma. The ion and electron plasmas are each considered to have Maxwellian velocity distributions. However, it is shown that the electron plasma must have a temperature that is higher than that of the ion plasma when the ions have low charge states. The work reported includes a self-consistent prediction of a possible plasma equilibrium

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.

Surface studies of Li-ion and Mg battery electrodes

Science.gov (United States)

Esbenshade, Jennifer

This dissertation focuses on studies of the surfaces of both Li-ion and Mg-ion battery electrodes. A fundamental understanding of processes occurring at the electrode surface is vital to the development of advanced battery systems. Additionally, modifications to the electrode surfaces are made and further characterized for improved performance. LiMn2O4 Cathodes for Li-ion Batteries: Effect of Mn in electrolyte on anode and Au coating to minimize dissolution: LiMn2O4 (LMO) is known to dissolve Mn ions with cycling. This section focuses on both the effect of the dissolution of Mn2+ into the electrolyte as well as Au coating on the LMO to improve electrochemical performance. Electrochemical quartz crystal microbalance (EQCM) was used to monitor changes in mass on the anode, SEM and AES were used to observe changes in surface morphology and chemical composition, and potentiostatic voltammetry was used to monitor charge and discharge capacity. The effect of Cu2+ addition in place of Mn2+ was also studied, as Cu is known to form an underpotential deposition (UPD) monolayer on Au electrodes. Following this, LMO particles were coated with a Au shell by a simple and scalable electroless deposition for use as Li-ion battery cathodes. The Au shell was intended to limit the capacity fade commonly seen with LMO cathodes by reducing the dissolution of Mn. Characterization by SEM, TEM, EELS, and AFM showed that the Au shell was approximately 3 nm thick. The Au shell prevented much of the Mn from dissolving in the electrolyte with 82% and 88% less dissolved Mn in the electrolyte at room temperature and 65 ºC, respectively, as compared to the uncoated LMO. Electrochemical performance studies with half cells showed that the Au shell maintained a higher discharge capacity over 400 cycles by nearly 30% with 110 mA hr g-1 for the 400th cycle as compared to a commercial LMO at 85 mA hr g-1. Similarly, the capacity fade was reduced in full cells: the coated LMO had 47% greater capacity

Eliminating degradation and uncovering ion-trapping dynamics in electrochromic WO3 thin films

Science.gov (United States)

Wen, Rui-Tao; Granqvist, Claes G.; Niklasson, Gunnar A.

2015-01-01

Amorphous WO3 thin films are of keen interest as cathodic electrodes in transmittance-modulating electrochromic devices. However, these films suffer from ion-trapping-induced degradation of optical modulation and reversibility upon extended Li+-ion exchange. Here, we demonstrate that ion-trapping-induced degradation, which is commonly believed to be irreversible, can be successfully eliminated by constant-current-driven de-trapping, i.e., WO3 films can be rejuvenated and regain their initial highly reversible electrochromic performance. Pronounced ion-trapping occurs when x exceeds ~0.65 in LixWO3 during ion insertion. We find two main kinds of Li+-ion trapping sites (intermediate and deep) in WO3, where the intermediate ones are most prevalent. Li+-ions can be completely removed from intermediate traps but are irreversibly bound in deep traps. Our results provide a general framework for developing and designing superior electrochromic materials and devices. PMID:26259104

A quadrupole ion trap as low-energy cluster ion beam source

CERN Document Server

Uchida, N; Kanayama, T

2003-01-01

Kinetic energy distribution of ion beams was measured by a retarding field energy analyzer for a mass-selective cluster ion beam deposition system that uses a quadrupole ion trap as a cluster ion beam source. The results indicated that the system delivers a cluster-ion beam with energy distribution of approx 2 eV, which corresponded well to the calculation results of the trapping potentials in the ion trap. Using this deposition system, mass-selected hydrogenated Si cluster ions Si sub n H sub x sup + were actually deposited on Si(111)-(7x7) surfaces at impact kinetic energy E sub d of 3-30 eV. Observation by using a scanning tunneling microscope (STM) demonstrated that Si sub 6 H sub x sup + cluster ions landed on the surface without decomposition at E sub d =3 eV, while the deposition was destructive at E sub d>=18 eV. (author)

Penning traps with unitary architecture for storage of highly charged ions.

Science.gov (United States)

Tan, Joseph N; Brewer, Samuel M; Guise, Nicholas D

2012-02-01

Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used in unitary architectures that couple the electric and magnetic components into an integrated structure. We have constructed a two-magnet Penning trap with radial access to enable the use of laser or atomic beams, as well as the collection of light. An experimental apparatus equipped with ion optics is installed at the NIST electron beam ion trap (EBIT) facility, constrained to fit within 1 meter at the end of a horizontal beamline for transporting highly charged ions. Highly charged ions of neon and argon, extracted with initial energies up to 4000 eV per unit charge, are captured and stored to study the confinement properties of a one-magnet trap and a two-magnet trap. Design considerations and some test results are discussed.

Penning traps with unitary architecture for storage of highly charged ions

International Nuclear Information System (INIS)

Tan, Joseph N.; Guise, Nicholas D.; Brewer, Samuel M.

2012-01-01

Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used in unitary architectures that couple the electric and magnetic components into an integrated structure. We have constructed a two-magnet Penning trap with radial access to enable the use of laser or atomic beams, as well as the collection of light. An experimental apparatus equipped with ion optics is installed at the NIST electron beam ion trap (EBIT) facility, constrained to fit within 1 meter at the end of a horizontal beamline for transporting highly charged ions. Highly charged ions of neon and argon, extracted with initial energies up to 4000 eV per unit charge, are captured and stored to study the confinement properties of a one-magnet trap and a two-magnet trap. Design considerations and some test results are discussed.

Integrated fiber-mirror ion trap for strong ion-cavity coupling

International Nuclear Information System (INIS)

Brandstätter, B.; Schüppert, K.; Casabone, B.; Friebe, K.; Stute, A.; Northup, T. E.; McClung, A.; Schmidt, P. O.; Deutsch, C.; Reichel, J.; Blatt, R.

2013-01-01

We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 μm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate

Surface negative ion production in ion sources

International Nuclear Information System (INIS)

Belchenko, Y.

1993-01-01

Negative ion sources and the mechanisms for negative ion production are reviewed. Several classes of sources with surface origin of negative ions are examined in detail: surface-plasma sources where ion production occurs on the electrode in contact with the plasma, and ''pure surface'' sources where ion production occurs due to conversion or desorption processes. Negative ion production by backscattering, impact desorption, and electron- and photo-stimulated desorption are discussed. The experimental efficiencies of intense surface negative ion production realized on electrodes contacted with hydrogen-cesium or pure hydrogen gas-discharge plasma are compared. Recent modifications of surface-plasma sources developed for accelerator and fusion applications are reviewed in detail

Detection and clearing of trapped ions in the high current Cornell photoinjector

Directory of Open Access Journals (Sweden)

S. Full

2016-03-01

Full Text Available We have recently performed experiments to test the effectiveness of three ion-clearing strategies in the Cornell high intensity photoinjector: DC clearing electrodes, bunch gaps, and beam shaking. The photoinjector reaches a new regime of linac beam parameters where high continuous wave beam currents lead to ion trapping. Therefore ion mitigation strategies must be evaluated for this machine and other similar future high current linacs. We have developed several techniques to directly measure the residual trapped ions. Our two primary indicators of successful clearing are the amount of ion current removed by a DC clearing electrode, and the absence of bremsstrahlung radiation generated by beam-ion interactions. Measurements were taken for an electron beam with an energy of 5 MeV and continuous wave beam currents in the range of 1–20 mA. Several theoretical models have been developed to explain our data. Using them, we are able to estimate the clearing electrode voltage required for maximum ion clearing, the creation and clearing rates of the ions while employing bunch gaps, and the sinusoidal shaking frequency necessary for clearing via beam shaking. In all cases, we achieve a maximum ion clearing of at least 70% or higher, and in some cases our data is consistent with full ion clearing.

Trapping radioactive ions

CERN Document Server

Kluge, Heinz-Jürgen

2004-01-01

Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning.

Trapping radioactive ions

International Nuclear Information System (INIS)

Kluge, H.-J.; Blaum, K.

2004-01-01

Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning

High-Fidelity Trapped-Ion Quantum Logic Using Near-Field Microwaves.

Science.gov (United States)

Harty, T P; Sepiol, M A; Allcock, D T C; Ballance, C J; Tarlton, J E; Lucas, D M

2016-09-30

We demonstrate a two-qubit logic gate driven by near-field microwaves in a room-temperature microfabricated surface ion trap. We introduce a dynamically decoupled gate method, which stabilizes the qubits against fluctuating energy shifts and avoids the need to null the microwave field. We use the gate to produce a Bell state with fidelity 99.7(1)%, after accounting for state preparation and measurement errors. The gate is applied directly to ^{43}Ca^{+} hyperfine "atomic clock" qubits (coherence time T_{2}^{*}≈50  s) using the oscillating magnetic field gradient produced by an integrated microwave electrode.

Plasma immersion ion implantation of the interior surface of a large cylindrical bore using an auxiliary electrode

International Nuclear Information System (INIS)

Zeng, X.C.; Kwok, T.K.; Liu, A.G.; Chu, P.K.; Tang, B.Y.

1998-01-01

A model utilizing cold, unmagnetized, and collisionless fluid ions as well as Boltzmann electrons is used to comprehensively investigate the sheath expansion into a translationally invariant large bore in the presence of an auxiliary electrode during plasma immersion ion implantation (PIII) of a cylindrical bore sample. The governing equation of ion continuity, ion motion, and Poisson close-quote s equation are solved by using a numerical finite difference method for different cylindrical bore radii, auxiliary electrode radii, and voltage rise times. The ion density and ion impact energy at the cylindrical inner surface, as well as the ion energy distribution, maximum ion impact energy, and average ion impact energy for the various cases are obtained. Our results show a dramatic improvement in the impact energy when an auxiliary electrode is used and the recommended normalized auxiliary electrode radius is in the range of 0.1 endash 0.3. copyright 1998 American Institute of Physics

Influence of surface oxidation on ion dynamics and capacitance in porous and nonporous carbon electrodes

Energy Technology Data Exchange (ETDEWEB)

Dyatkin, Boris [Drexel Univ., Philadelphia, PA (United States); Zhang, Yu [Vanderbilt Univ., Nashville, TN (United States); Mamontov, Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kolesnikov, Alexander I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cheng, Yongqiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cummings, Peter T. [Vanderbilt Univ., Nashville, TN (United States); Gogotsi, Yury G. [Drexel Univ., Philadelphia, PA (United States)

2016-04-07

Here, we investigate the influence of surface chemistry and ion confinement on capacitance and electrosorption dynamics of room-temperature ionic liquids (RTILs) in supercapacitors. Using air oxidation and vacuum annealing, we produced defunctionalized and oxygen-rich surfaces of carbide-derived carbons (CDCs) and graphene nanoplatelets (GNPs). While oxidized surfaces of porous CDCs improve capacitance and rate handling abilities of ions, defunctionalized nonporous GNPs improve charge storage densities on planar electrodes. Quasi-elastic neutron scattering (QENS) and inelastic neutron scattering (INS) probed the structure, dynamics, and orientation of RTIL ions confined in divergently functionalized pores. Oxidized, ionophilic surfaces draw ions closer to pore surfaces and enhance potential-driven ion transport during electrosorption. Molecular dynamics (MD) simulations corroborated experimental data and demonstrated the significance of surface functional groups on ion orientations, accumulation densities, and capacitance.

Ion manipulation method and device

Energy Technology Data Exchange (ETDEWEB)

Anderson, Gordon A.; Baker, Erin M.; Smith, Richard D.; Ibrahim, Yehia M.

2017-11-07

An ion manipulation method and device is disclosed. The device includes a pair of substantially parallel surfaces. An array of inner electrodes is contained within, and extends substantially along the length of, each parallel surface. The device includes a first outer array of electrodes and a second outer array of electrodes. Each outer array of electrodes is positioned on either side of the inner electrodes, and is contained within and extends substantially along the length of each parallel surface. A DC voltage is applied to the first and second outer array of electrodes. A RF voltage, with a superimposed electric field, is applied to the inner electrodes by applying the DC voltages to each electrode. Ions either move between the parallel surfaces within an ion confinement area or along paths in the direction of the electric field, or can be trapped in the ion confinement area.

Cryogenic trapping of keV ion beams at the CSR prototype

Energy Technology Data Exchange (ETDEWEB)

Menk, Sebastian; Blaum, Klaus; Froese, Michael; Grieser, Manfred; Lange, Michael; Orlov, Dimitry; Sieber, Thomas; Hahn, Robert von; Varju, Jozef; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Heber, Oded; Rappaport, Michael; Zajfman, Daniel [Weizmann Institut of Science, Rehovot (Israel)

2009-07-01

A Cryogenic Trap for Fast ion beams (CTF) was built to explore cooling techniques and test thermal decoupling of ion optics for the development of the electrostatic Cryogenic Storage Ring (CSR). These challenging projects will lead to a new experimental field of atomic and molecular physics with keV ion beams. The cold conditions of 2-10 K minimize the blackbody radiation field and are expected to lead to extremely low restgas densities (equivalent pressure at room temperature {approx}10{sup -13} mbar) which result in long storage lifetimes and for molecular ions to radiative cooling to their ro-vibrational ground states. The CTF consists of two stacks of electrostatic mirror electrodes allowing the storage of up to 20 keV ion beams. Cryogenic ion beam storage has been realized with this device using a liquid helium refrigeration system to cool down the experimental trapping area to few-Kelvin cryogenic temperatures and experiments with cryogenically trapped molecular nitrogen ions have been performed to verify the low vacuum conditions by measuring their storage lifetimes.

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1983-01-01

Ion-Selective Electrode Reviews, Volume 5 is a collection of articles that covers ion-speciation. The book aims to present the advancements of the range and capabilities of selective ion-sensors. The topics covered in the selection are neutral carrier based ion-selective electrodes; reference electrodes and liquid junction effects in ion-selective electrode potentiometry; ion transfer across water/organic phase boundaries and analytical; and carbon substrate ion-selective electrodes. The text will be of great use to chemists and chemical engineers.

Lifetime measurements in an electrostatic ion beam trap using image charge monitoring

International Nuclear Information System (INIS)

Rahinov, Igor; Toker, Yoni; Heber, Oded; Rappaport, Michael; Zajfman, Daniel; Strasser, Daniel; Schwalm, Dirk

2012-01-01

A technique for mass-selective lifetime measurements of keV ions in a linear electrostatic ion beam trap is presented. The technique is based on bunching the ions using a weak RF potential and non-destructive ion detection by a pick-up electrode. This method has no mass-limitation, possesses the advantage of inherent mass-selectivity, and offers a possibility of measuring simultaneously the lifetimes of different ion species with no need for prior mass-selection.

Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion

Energy Technology Data Exchange (ETDEWEB)

Cornejo, J. M.; Colombano, M.; Doménech, J.; Rodríguez, D., E-mail: danielrodriguez@ugr.es [Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada (Spain); Block, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institut Mainz, 55099 Mainz (Germany); Institut für Kernchemie, University of Mainz, 55099 Mainz (Germany); Delahaye, P. [Grand Accélérateur National d’Ions Lourds, 14000 Caen (France)

2015-10-15

A special ion trap was initially built up to perform β-ν correlation experiments with radioactive ions. The trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single {sup 40}Ca{sup +} ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on {sup 40}Ca{sup +} ions, starting from large clouds and reaching single ion sensitivity. This new feature of the trap might be important also for other experiments with ions produced at radioactive ion beam facilities. In this publication, the trap and the laser system will be described, together with their performance with respect to laser cooling applied to large ion clouds down to a single ion.

A cylindrical Penning trap for capture, mass selective cooling, and bunching of radioactive ion beams

International Nuclear Information System (INIS)

Raimbault-Hartmann, H.; Bollen, G.; Beck, D.; Koenig, M.; Kluge, H.-J.; Schwarz, S.; Schark, E.; Stein, J.; Szerypo, J.

1997-01-01

A Penning trap ion accumulator, cooler, and buncher for low-energy ion beams has been developed for the ISOLTRAP mass spectrometer at ISOLDE/CERN. A cylindrical electrode configuration is used for the creation of a nested trapping potential. This is required for efficient accumulation of externally produced ions and for high-mass selectivity by buffer gas cooling. The design goal of a mass resolving power of about 1 x 10 5 has been achieved. Isobar separation has been demonstrated for radioactive rare-earth ion beams delivered by the ISOLDE on-line mass separator. (orig.)

A cylindrical Penning trap for capture, mass selective cooling, and bunching of radioactive ion beams

CERN Document Server

Raimbault-Hartmann, H; Bollen, G; König, M; Kluge, H J; Schark, E; Stein, J; Schwarz, S; Szerypo, J

1997-01-01

A Penning trap ion accumulator, cooler, and buncher for low energy ion beams has been developed for the ISOLTRAP mass spectrometer at ISOLDE/CERN. A cylindrical electrode configuration is used for the creation of a nested trapping potential. This is required for efficient accumulation of externally produced ions and for high mass selectivity by buffer gas cooling. The design goal of a mass resolving power of about $1\\cdot 10^{5}$ has been achieved. Isobar separation has been demonstrated for radioactive rare earth ion beams delivered by the ISOLDE on-line mass separator.

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.

Ion trap architectures and new directions

Science.gov (United States)

Siverns, James D.; Quraishi, Qudsia

2017-12-01

Trapped ion technology has seen advances in performance, robustness and versatility over the last decade. With increasing numbers of trapped ion groups worldwide, a myriad of trap architectures are currently in use. Applications of trapped ions include: quantum simulation, computing and networking, time standards and fundamental studies in quantum dynamics. Design of such traps is driven by these various research aims, but some universally desirable properties have lead to the development of ion trap foundries. Additionally, the excellent control achievable with trapped ions and the ability to do photonic readout has allowed progress on quantum networking using entanglement between remotely situated ion-based nodes. Here, we present a selection of trap architectures currently in use by the community and present their most salient characteristics, identifying features particularly suited for quantum networking. We also discuss our own in-house research efforts aimed at long-distance trapped ion networking.

Ions kinematics in an electrostatic ion beam trap

Energy Technology Data Exchange (ETDEWEB)

Attia, D

2004-06-01

In this study, I have tried to provide a better understanding of the dynamics of ions inside an electrostatic ion beam trap. The electrostatic ion trap allows to store ions moving between two electrostatic mirrors. Although the trap has been developed already seven years ago, no direct measurement of the transversal velocity distribution of the ions has been performed. Such quantity is central for understanding the conditions under which a beam should be produced (mainly emittance) in order to be trapped by such a device. The data I have obtained during the course of this work are based on an experimental technique which relies on the direct imaging of the particles exiting the trap, as well as on numerical simulations of the ion trajectories inside the trap. I have personally been involved in the hardware development of the imaging system, the data acquisition and analysis of the data as well as il all numerical calculations presented here. These results allow us to obtain, for the first time, experimental information on the transverse phase space of the trap, and contribute to the overall understanding of the ion motion in this system. (author)

Ion Storage Tests with the High Performance Antimatter Trap (HiPAT)

Science.gov (United States)

Martin, James J.; Lewis, Raymond A.; Chakrabarti, Suman; Pearson, Boise; Schafer, Charles (Technical Monitor)

2002-01-01

The NASA/Marshall Space Flight Centers (NASA/MSFC) Propulsion Research Center (PRC) is evaluating an antiproton storage system, referred to as the High Performance Antiproton Trap (HiPAT). This interest stems from the sheer energy represented by matter/antimatter annihilation process with has an energy density approximately 10 order of magnitude above that of chemical propellants. In other terms, one gram of antiprotons contains the equivalent energy of approximately 23 space shuttle external tanks or ET's (each ET contains roughly 740,000 kgs of fuel and oxidizer). This incredible source of stored energy, if harnessed, would be an enabling technology for deep space mission where both spacecraft weight and propulsion performance are key to satisfying aggressive mission requirements. The HiPAT hardware consists of a 4 Tesla superconductor system, an ultra high vacuum test section (vacuum approaching 10(exp -12) torr), and a high voltage confinement electrode system (up to 20 kvolts operation). The current laboratory layout is illustrated. The HiPAT designed objectives included storage of up to 1 trillion antiprotons with corresponding lifetimes approaching 18 days. To date, testing has centered on the storage of positive hydrogen ions produced in situ by a stream of high-energy electrons that passes through the trapping region. However, due to space charge issues and electron beam compression as it passes through the HiPAT central field, current ion production is limited to less then 50,000 ions. Ion lifetime was determined by counting particle populations at the end of various storage time intervals. Particle detection was accomplished by destructively expelling the ions against a micro-channel plate located just outside the traps magnetic field. The effect of radio frequency (RF) stabilization on the lifetime of trapped particles was also examined. This technique, referred to as a rotating wall, made use of a segmented electrode located near the center of the trap

Experimental investigation of the stability diagram for Paul traps in the case of praseodymium ions

International Nuclear Information System (INIS)

Koczorowski, W.; Szawiola, G.; Walaszyk, A.; Buczek, A.; Stefanska, D.; Stachowska, E.

2006-01-01

The present paper describes an investigation of non-linear resonances of praseodymium ion clouds stored in a Paul trap as a function of the storage parameters. These have been observed in traps with different ring electrode diameters. In these different traps the resonances occur for different values of the operating parameters. Discrepancies with the approximation model for one ion have been found. The intensity of the fluorescence signal and the Doppler half width have been recorded as a function of one of the storage parameters: q. We use our results to optimize the fluorescence signal of the stored ions, which is especially useful in the case of the double-resonance method.

Enhanced light trapping by focused ion beam (FIB) induced self-organized nanoripples on germanium (100) surface

Science.gov (United States)

Kamaliya, Bhaveshkumar; Mote, Rakesh G.; Aslam, Mohammed; Fu, Jing

2018-03-01

In this paper, we demonstrate enhanced light trapping by self-organized nanoripples on the germanium surface. The enhanced light trapping leading to high absorption of light is confirmed by the experimental studies as well as the numerical simulations using the finite-difference time-domain method. We used gallium ion (Ga+) focused ion beam to enable the formation of the self-organized nanoripples on the germanium (100) surface. During the fabrication, the overlap of the scanning beam is varied from zero to negative value and found to influence the orientation of the nanoripples. Evolution of nanostructures with the variation of beam overlap is investigated. Parallel, perpendicular, and randomly aligned nanoripples with respect to the scanning direction are obtained via manipulation of the scanning beam overlap. 95% broadband absorptance is measured in the visible electromagnetic region for the nanorippled germanium surface. The reported light absorption enhancement can significantly improve the efficiency of germanium-silicon based photovoltaic systems.

A computation study on the interplay between surface morphology and electrochemical performance of patterned thin film electrodes for Li-ion batteries

Science.gov (United States)

Gur, Sourav; Frantziskonis, George N.; Aifantis, Katerina E.

2017-08-01

Recent experiments illustrate that the morphology of the electrode surface impacts the voltage - capacity curves and long term cycling performance of Li-ion batteries. The present study systematically explores the role of the electrode surface morphology and uncertainties in the reactions that occur during electrochemical cycling, by performing kinetic Monte Carlo (kMC) simulations using the lattice Boltzmann method (LBM). This allows encoding of the inherent stochasticity at discrete microscale reaction events over the deterministic mean field reaction dynamics that occur in Li-ion cells. The electrodes are taken to be dense thin films whose surfaces are patterned with conical, trapezoidal, dome-shaped, or pillar-shaped structures. It is shown that the inherent perturbations in the reactions together with the characteristics of the electrode surface configuration can significantly improve battery performance, mainly because patterned surfaces, as opposed to flat surfaces, result in a smaller voltage drop. The most efficient pattern was the trapezoidal, which is consistent with experimental evidence on Si patterned electrodes.

Effects of ion implantation on the electrochemical characteristics of carbon electrodes

International Nuclear Information System (INIS)

Takahashi, Katsuo; Iwaki, Masaya

1994-01-01

Various carbon materials are important electrode materials for electrochemical field. By ion implantation, the surface layer reforming of carbon materials (mainly galssy carbon) was carried out, and the effect that it exerts to their electrode characteristics was investigated. As the results of the ion implantation of Li, N, O, K, Ti, Zn, Cd and others performed so far, it was found that mainly by the change of the surface layer to amorphous state, there were the effects of the lowering of base current and the lowering of electrode reaction rate, and it was known that the surface layers of carbon materials doped with various kinds of ions showed high chemical stability. The use of carbon materials as electrodes in electrochemistry is roughly divided into the electrodes for electrolytic industry and fuel cells for large current and those for the measurement in electrochemical reaction for small current. The structure of carbon materials and electrode characteristics, and the reforming effect by ion implantation are reported. (K.I.)

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1985-01-01

Ion-Selective Electrode Reviews, Volume 7 is a collection of papers that covers the applications of electrochemical sensors, along with the versatility of ion-selective electrodes. The coverage of the text includes solid contact in membrane ion-selective electrodes; immobilized enzyme probes for determining inhibitors; potentiometric titrations based on ion-pair formation; and application of ion-selective electrodes in soil science, kinetics, and kinetic analysis. The text will be of great use to chemists and chemical engineers.

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1982-01-01

Ion-Selective Electrode Reviews, Volume 3, provides a review of articles on ion-selective electrodes (ISEs). The volume begins with an article on methods based on titration procedures for surfactant analysis, which have been developed for discrete batch operation and for continuous AutoAnalyser use. Separate chapters deal with detection limits of ion-selective electrodes; the possibility of using inorganic ion-exchange materials as ion-sensors; and the effect of solvent on potentials of cells with ion-selective electrodes. Also included is a chapter on advances in calibration procedures, the d

Advanced ion trap structures with integrated tools for qubit manipulation

Science.gov (United States)

Sterk, J. D.; Benito, F.; Clark, C. R.; Haltli, R.; Highstrete, C.; Nordquist, C. D.; Scott, S.; Stevens, J. E.; Tabakov, B. P.; Tigges, C. P.; Moehring, D. L.; Stick, D.; Blain, M. G.

2012-06-01

We survey the ion trap fabrication technologies available at Sandia National Laboratories. These include four metal layers, precision backside etching, and low profile wirebonds. We demonstrate loading of ions in a variety of ion traps that utilize these technologies. Additionally, we present progress towards integration of on-board filtering with trench capacitors, photon collection via an optical cavity, and integrated microwave electrodes for localized hyperfine qubit control and magnetic field gradient quantum gates. [4pt] This work was supported by Sandia's Laboratory Directed Research and Development (LDRD) Program and the Intelligence Advanced Research Projects Activity (IARPA). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Microwave quantum logic gates for trapped ions.

Science.gov (United States)

Ospelkaus, C; Warring, U; Colombe, Y; Brown, K R; Amini, J M; Leibfried, D; Wineland, D J

2011-08-10

Control over physical systems at the quantum level is important in fields as diverse as metrology, information processing, simulation and chemistry. For trapped atomic ions, the quantized motional and internal degrees of freedom can be coherently manipulated with laser light. Similar control is difficult to achieve with radio-frequency or microwave radiation: the essential coupling between internal degrees of freedom and motion requires significant field changes over the extent of the atoms' motion, but such changes are negligible at these frequencies for freely propagating fields. An exception is in the near field of microwave currents in structures smaller than the free-space wavelength, where stronger gradients can be generated. Here we first manipulate coherently (on timescales of 20 nanoseconds) the internal quantum states of ions held in a microfabricated trap. The controlling magnetic fields are generated by microwave currents in electrodes that are integrated into the trap structure. We also generate entanglement between the internal degrees of freedom of two atoms with a gate operation suitable for general quantum computation; the entangled state has a fidelity of 0.76(3), where the uncertainty denotes standard error of the mean. Our approach, which involves integrating the quantum control mechanism into the trapping device in a scalable manner, could be applied to quantum information processing, simulation and spectroscopy.

New experimental initiatives using very highly charged ions from an 'electron beam ion trap'

International Nuclear Information System (INIS)

Schneider, D.

1996-01-01

A short review of the experimental program in highly-charged heavy ion physics conducted at the Lawrence Livermore National Laboratory Electron Beam Ion Trap (EBIT) facility is presented. The heavy-ion research, involving ions up to fully stripped U 92+ , includes precision x-ray spectroscopy and lifetime studies, electron impact ionization and excitation cross section measurements. The investigations of ion-surface interactions following the impact of high-Z highly charged ions on surfaces are aimed to study the neutralization dynamics effecting the ion and the response of the surface as well. (author)

Simulating the performance of a distance-3 surface code in a linear ion trap

Science.gov (United States)

Trout, Colin J.; Li, Muyuan; Gutiérrez, Mauricio; Wu, Yukai; Wang, Sheng-Tao; Duan, Luming; Brown, Kenneth R.

2018-04-01

We explore the feasibility of implementing a small surface code with 9 data qubits and 8 ancilla qubits, commonly referred to as surface-17, using a linear chain of 171Yb+ ions. Two-qubit gates can be performed between any two ions in the chain with gate time increasing linearly with ion distance. Measurement of the ion state by fluorescence requires that the ancilla qubits be physically separated from the data qubits to avoid errors on the data due to scattered photons. We minimize the time required to measure one round of stabilizers by optimizing the mapping of the two-dimensional surface code to the linear chain of ions. We develop a physically motivated Pauli error model that allows for fast simulation and captures the key sources of noise in an ion trap quantum computer including gate imperfections and ion heating. Our simulations showed a consistent requirement of a two-qubit gate fidelity of ≥99.9% for the logical memory to have a better fidelity than physical two-qubit operations. Finally, we perform an analysis of the error subsets from the importance sampling method used to bound the logical error rates to gain insight into which error sources are particularly detrimental to error correction.

A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy

Science.gov (United States)

Rajagopal, Vaishnavi; Stokes, Chris; Ferzoco, Alessandra

2018-02-01

We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 107 detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes.

IMPROVEMENT OF THE CERN SPS ELECTROSTATIC SEPTA ION TRAPS

CERN Multimedia

Balhan, Bruno; Barlow, Roger Andrew; Raffaele, Graziano

2016-01-01

At CERN, the SPS synchrotron is equipped with a slow extraction channel towards the fixed target beam lines in the North Area This channel includes five consecutive electrostatic septa, where the field free region and the active high field region are separated by an array of tungsten-rhenium wires. The field-free region provides for the circulating beam, while the high field region is used to deflect the extracted beam. Since the residual gas can be ionized by the orbiting beam, low energy ions could cross the wire array and enter the high field region and cause high voltage breakdown when accelerated onto the cathode. To prevent low energy ions from entering this high electric field region, a vertical field is applied to the orbiting beam using so-called ‘ion traps’ for active protection. The vertical field is created by electrodes placed inside the region containing the circulating beam. Due to electromagnetic coupling onto the ion trap electrodes observed with the high frequency LHC beam (25 ns spaced ...

Technologies for Trapped-Ion Quantum Information Systems

Science.gov (United States)

2016-03-21

we discuss work aiming to leverage a commer- cial CMOS (complementary metal-oxide- semiconductor ) process to develop an integrated ion trap architecture...this integration: alignment of optical elements with tiny modes to point emitters, and trap- ping charged particles close to dielectric surfaces. Inte...far by heating in several ways. The deep optical potentials required to confine a charged particle against stray fields impart significant recoil

Optical Trapping of Ion Coulomb Crystals

Science.gov (United States)

Schmidt, Julian; Lambrecht, Alexander; Weckesser, Pascal; Debatin, Markus; Karpa, Leon; Schaetz, Tobias

2018-04-01

The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

Ion production and trapping in electron rings

International Nuclear Information System (INIS)

Gluckstern, R.C.; Ruggiero, A.G.

1979-08-01

The electron beam in the VUV and X-ray rings of NSLS will ionize residual gas by collisions. Positive ions will be produced with low velocity, and will be attracted by the electron beam to the beam axis. If they are trapped in stable (transverse) orbits, they may accumulate, thereby increasing the ν/sub x,z/ of the individual electrons. Since the accumulated ions are unlikely to be of uniform density, a spread in ν/sub x,z/ will also occur. Should these effects be serious, it may be necessary to introduce clearing electrodes, although this may increase Z/n in the rings, thereby adding to longitudinal instability problems. The seriousness of the above effect for the VUV and X-ray rings is estimated

Optical Trapping of Ion Coulomb Crystals

Directory of Open Access Journals (Sweden)

Julian Schmidt

2018-05-01

Full Text Available The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

Spin resonance with trapped ions

Energy Technology Data Exchange (ETDEWEB)

Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E [Institut fuer Laser-Physik, Universitaet Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany)

2003-03-14

A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped {sup 171}Yb{sup +}, we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states.

Spin resonance with trapped ions

International Nuclear Information System (INIS)

Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E

2003-01-01

A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped 171 Yb + , we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states

A cylindrical quadrupole ion trap in combination with an electrospray ion source for gas-phase luminescence and absorption spectroscopy

International Nuclear Information System (INIS)

Stockett, Mark H.; Houmøller, Jørgen; Støchkel, Kristian; Svendsen, Annette; Brøndsted Nielsen, Steen

2016-01-01

A relatively simple setup for collection and detection of light emitted from isolated photo-excited molecular ions has been constructed. It benefits from a high collection efficiency of photons, which is accomplished by using a cylindrical ion trap where one end-cap electrode is a mesh grid combined with an aspheric condenser lens. The geometry permits nearly 10% of the emitted light to be collected and, after transmission losses, approximately 5% to be delivered to the entrance of a grating spectrometer equipped with a detector array. The high collection efficiency enables the use of pulsed tunable lasers with low repetition rates (e.g., 20 Hz) instead of continuous wave (cw) lasers or very high repetition rate (e.g., MHz) lasers that are typically used as light sources for gas-phase fluorescence experiments on molecular ions. A hole has been drilled in the cylinder electrode so that a light pulse can interact with the ion cloud in the center of the trap. Simulations indicate that these modifications to the trap do not significantly affect the storage capability and the overall shape of the ion cloud. The overlap between the ion cloud and the laser light is basically 100%, and experimentally >50% of negatively charged chromophore ions are routinely photodepleted. The performance of the setup is illustrated based on fluorescence spectra of several laser dyes, and the quality of these spectra is comparable to those reported by other groups. Finally, by replacing the optical system with a channeltron detector, we demonstrate that the setup can also be used for gas-phase action spectroscopy where either depletion or fragmentation is monitored to provide an indirect measurement on the absorption spectrum of the ion.

A cylindrical quadrupole ion trap in combination with an electrospray ion source for gas-phase luminescence and absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Stockett, Mark H., E-mail: stockett@phys.au.dk; Houmøller, Jørgen; Støchkel, Kristian; Svendsen, Annette; Brøndsted Nielsen, Steen [Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark)

2016-05-15

A relatively simple setup for collection and detection of light emitted from isolated photo-excited molecular ions has been constructed. It benefits from a high collection efficiency of photons, which is accomplished by using a cylindrical ion trap where one end-cap electrode is a mesh grid combined with an aspheric condenser lens. The geometry permits nearly 10% of the emitted light to be collected and, after transmission losses, approximately 5% to be delivered to the entrance of a grating spectrometer equipped with a detector array. The high collection efficiency enables the use of pulsed tunable lasers with low repetition rates (e.g., 20 Hz) instead of continuous wave (cw) lasers or very high repetition rate (e.g., MHz) lasers that are typically used as light sources for gas-phase fluorescence experiments on molecular ions. A hole has been drilled in the cylinder electrode so that a light pulse can interact with the ion cloud in the center of the trap. Simulations indicate that these modifications to the trap do not significantly affect the storage capability and the overall shape of the ion cloud. The overlap between the ion cloud and the laser light is basically 100%, and experimentally >50% of negatively charged chromophore ions are routinely photodepleted. The performance of the setup is illustrated based on fluorescence spectra of several laser dyes, and the quality of these spectra is comparable to those reported by other groups. Finally, by replacing the optical system with a channeltron detector, we demonstrate that the setup can also be used for gas-phase action spectroscopy where either depletion or fragmentation is monitored to provide an indirect measurement on the absorption spectrum of the ion.

Laser induced fluorescence of trapped molecular ions

Energy Technology Data Exchange (ETDEWEB)

Grieman, F.J.

1979-10-01

An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references.

Laser induced fluorescence of trapped molecular ions

International Nuclear Information System (INIS)

Grieman, F.J.

1979-10-01

An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references

Practical aspects of trapped ion mass spectrometry, 5 applications of ion trapping devices

CERN Document Server

March, Raymond E

2009-01-01

Examines ion/neutral and ion/ion reactions, ion spectroscopy, and the structural characterization of proteins and peptides using quadropole ion trap mass spectrometry, Fourier transform - ion cyclotron resonance (FT-ICR) mass spectrometry, and traveling wave ion mobility mass spectrometry.

Systems and Methods for Ejection of Ions from an Ion Trap

Science.gov (United States)

Cooks, Robert Graham (Inventor); Snyder, Dalton (Inventor)

2018-01-01

The invention generally relates to systems and methods for ejection of ions from an ion trap. In certain embodiments, systems and methods of the invention sum two different frequency signals into a single summed signal that is applied to an ion trap. In other embodiments, an amplitude of a single frequency signal is modulated as the single frequency signal is being applied to the ion trap. In other embodiments, a first alternating current (AC) signal is applied to an ion trap that varies as a function of time, while a constant radio frequency (RF) signal is applied to the ion trap.

Plasma flow between equipotential electrodes in an ion current transport mode

International Nuclear Information System (INIS)

Zimin, A.M.; Morozov, A.I.

1995-01-01

The paper deals with calculation of parameters in accelerator channel and near electrodes, when realizing ion current transport mode. Model on the basis of two-dimensional two-liquid nondissipative magnetohydrodynamics was formulated, and its solution for isomagnetic flow in smooth channel approximation was conducted. Change of parameters near anode surface was considered in detail. It is shown that regular joining of flow with equipotential electrodes without large near-electrode jumps is performed during ion current transport. Current distribution along accelerator length was calculated when determining ion intake through anode surface due to inertial-drift emission. It is shown that this mechanism can provide rather high current density in ion current transport. 10 refs.; 6 figs

Quantized motion of trapped ions

International Nuclear Information System (INIS)

Steinbach, J.

1999-01-01

This thesis is concerned with a theoretical and numerical study of the preparation and coherent manipulation of quantum states in the external and internal degrees of freedom of trapped ions. In its first part, this thesis proposes and investigates schemes for generating several nonclassical states for the quantized vibrational motion of a trapped ion. Based on dark state preparation specific laser excitation configurations are presented which, given appropriately chosen initial states, realize the desired motional states in the steady-state, indicated by the cessation of the fluorescence emitted by the ion. The focus is on the SU(1,1) intelligent states in both their single- and two-mode realization, corresponding to one- and two-dimensional motion of the ion. The presented schemes are also studied numerically using a Monte-Carlo state-vector method. The second part of the thesis describes how two vibrational degrees of freedom of a single trapped ion can be coupled through the action of suitably chosen laser excitation. Concentrating on a two-dimensional ion trap with dissimilar vibrational frequencies a variety of quantized two-mode couplings are derived. The focus is on a linear coupling that takes excitations from one mode to another. It is demonstrated how this can result in a state rotation, in which it is possible to coherently transfer the motional state of the ion between orthogonal directions without prior knowledge of that motional state. The third part of this thesis presents a new efficient method for generating maximally entangled internal states of a collection of trapped ions. The method is deterministic and independent of the number of ions in the trap. As the essential element of the scheme a mechanism for the realization of a controlled NOT operation that can operate on multiple ions is proposed. The potential application of the scheme for high-precision frequency standards is explored. (author)

Enhanced signal generation for use in the analysis of synthetic pyrethroids using chemical ionization tandem quadrupole ion trap mass spectrometry.

Science.gov (United States)

Sichilongo, Kwenga

2004-12-01

Synthetic pyrethroids fragment extensively under electron ionization (EI) conditions to give low mass ions, most of them with the same m/z ratios. This fragmentation is primarily due to the labile ester linkage found in these compounds. In this research we established the best gas chromatography (GC) conditions in the EI mode that served as a benchmark in the development of a chemical ionization (CI) protocol for ten selected synthetic pyrethroids. Based on proton affinity data, several reagent gases were evaluated in the positive CI ionization mode. Methanol was found to produce higher average ion counts relative to the other gases evaluated, which led to the development of an optimized method consisting of selective ejection chemical ionization (SECI) and MS/MS. Standard stainless steel ion trap electrodes produced significant degradation of chromatographic performance on late eluting compounds, which was attributed to electrode surface chemistry. A dramatic improvement in signal-to-noise (S/N) ratios was observed when the chromatographically inert Silcosteel coated electrodes were used. The resulting method, that has significant S/N ratio improvements resulting from a combination of septum programmable injections (SPI), optimized CI and inert Silcosteel-coated electrodes, was used to determine instrument detection limits.

The Aarhus Ion Micro-Trap Project

DEFF Research Database (Denmark)

Miroshnychenko, Yevhen; Nielsen, Otto; Poulsen, Gregers

As part of our involvement in the EU MICROTRAP project, we have designed, manufactured and assembled a micro-scale ion trap with integrated optical fibers. These prealigned fibers will allow delivering cooling laser light to single ions. Therefore, such a trap will not require any direct optical...... and installed in an ultra high vacuum chamber, which includes an ablation oven for all-optical loading of the trap [2]. The next steps on the project are to demonstrate the operation of the micro-trap and the cooling of ions using fiber delivered light. [1] D. Grant, Development of Micro-Scale Ion traps, Master...... Thesis (2008). [2] R.J. Hendricks, D.M. Grant, P.F. Herskind, A. Dantan and M. Drewsen, An all-optical ion-loading technique for scalable microtrap architectures, Applied Physics B, 88, 507 (2007)....

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.

Spectroscopy with trapped highly charged ions

International Nuclear Information System (INIS)

Beiersdorfer, Peter

2009-01-01

We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed; and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

Ultralow-Power Electronic Trapping of Nanoparticles with Sub-10 nm Gold Nanogap Electrodes.

Science.gov (United States)

Barik, Avijit; Chen, Xiaoshu; Oh, Sang-Hyun

2016-10-12

We demonstrate nanogap electrodes for rapid, parallel, and ultralow-power trapping of nanoparticles. Our device pushes the limit of dielectrophoresis by shrinking the separation between gold electrodes to sub-10 nm, thereby creating strong trapping forces at biases as low as the 100 mV ranges. Using high-throughput atomic layer lithography, we manufacture sub-10 nm gaps between 0.8 mm long gold electrodes and pattern them into individually addressable parallel electronic traps. Unlike pointlike junctions made by electron-beam lithography or larger micron-gap electrodes that are used for conventional dielectrophoresis, our sub-10 nm gold nanogap electrodes provide strong trapping forces over a mm-scale trapping zone. Importantly, our technology solves the key challenges associated with traditional dielectrophoresis experiments, such as high voltages that cause heat generation, bubble formation, and unwanted electrochemical reactions. The strongly enhanced fields around the nanogap induce particle-transport speed exceeding 10 μm/s and enable the trapping of 30 nm polystyrene nanoparticles using an ultralow bias of 200 mV. We also demonstrate rapid electronic trapping of quantum dots and nanodiamond particles on arrays of parallel traps. Our sub-10 nm gold nanogap electrodes can be combined with plasmonic sensors or nanophotonic circuitry, and their low-power electronic operation can potentially enable high-density integration on a chip as well as portable biosensing.

Sympathetic cooling of ions in a hybrid atom ion trap

Energy Technology Data Exchange (ETDEWEB)

Hoeltkemeier, Bastian

2016-10-27

In this thesis the dynamics of a trapped ion immersed in a spatially localized buffer gas is investigated. For a homogeneous buffer gas, the ion's energy distribution reaches a stable equilibrium only if the mass of the buffer gas atoms is below a critical value. This limitation can be overcome by using multipole traps in combination and/or a spatially confined buffer gas. Using a generalized model for elastic collisions of the ion with the buffer gas atoms, the ion's energy distribution is numerically determined for arbitrary buffer gas distributions and trap parameters. Three regimes characterized by the respective analytic form of the ion's equilibrium energy distribution are found. One of these is a novel regime at large atom-to-ion mass ratios where the final ion temperature can tuned by adiabatically decreasing the spatial extension of the buffer gas and the effective ion trap depth (forced sympathetic cooling). The second part of the thesis presents a hybrid atom ion trap designed for sympathetic cooling of hydroxide anions. In this hybrid trap the anions are immersed in a cloud of laser cooled rubidium atoms. The translational and rovibrational temperatures of the anions is probed by photodetachment tomography and spectroscopy which shows the first ever indication of sympathetic cooling of anions by laser cooled atoms.

Poly(ο-methoxyaniline) modified electrode for detection of lithium ions

International Nuclear Information System (INIS)

Lindino, Cleber Antonio; Casagrande, Marcella; Peiter, Andreia; Ribeiro, Caroline

2012-01-01

This paper reports the use of an electrode modified with poly(ο-methoxyaniline) for detecting lithium ions. These ions are present in drugs used for treating bipolar disorder and that requires periodical monitoring of the concentration of lithium in blood serum. Poly(ο-methoxyaniline) was obtained electrochemically by cyclic voltammetry on the surface of a gold electrode. The results showed that the electrode modified with a conducting polymer responded to lithium ions in the concentration range of 1 x 10 -5 to 1 x 10 -4 mol L -1 . The results also confirmed that the performance of the modified electrode was comparable to that of the standard method (atomic emission spectrophotometry). (author)

Poly({omicron}-methoxyaniline) modified electrode for detection of lithium ions

Energy Technology Data Exchange (ETDEWEB)

Lindino, Cleber Antonio; Casagrande, Marcella; Peiter, Andreia; Ribeiro, Caroline [Departamento de Quimica, Universidade Estadual do Oeste do Parana, Toledo, PR (Brazil)

2012-07-01

This paper reports the use of an electrode modified with poly({omicron}-methoxyaniline) for detecting lithium ions. These ions are present in drugs used for treating bipolar disorder and that requires periodical monitoring of the concentration of lithium in blood serum. Poly({omicron}-methoxyaniline) was obtained electrochemically by cyclic voltammetry on the surface of a gold electrode. The results showed that the electrode modified with a conducting polymer responded to lithium ions in the concentration range of 1 x 10{sup -5} to 1 x 10{sup -4} mol L{sup -1}. The results also confirmed that the performance of the modified electrode was comparable to that of the standard method (atomic emission spectrophotometry). (author)

Poly(o-methoxyaniline modified electrode for detection of lithium ions

Directory of Open Access Journals (Sweden)

Cleber Antonio Lindino

2012-01-01

Full Text Available This paper reports the use of an electrode modified with poly(o-methoxyaniline for detecting lithium ions. These ions are present in drugs used for treating bipolar disorder and that requires periodical monitoring of the concentration of lithium in blood serum. Poly(o-methoxyaniline was obtained electrochemically by cyclic voltammetry on the surface of a gold electrode. The results showed that the electrode modified with a conducting polymer responded to lithium ions in the concentration range of 1 x 10-5 to 1 x 10-4 mol L-1 . The results also confirmed that the performance of the modified electrode was comparable to that of the standard method (atomic emission spectrophotometry.

Method for fabricating carbon/lithium-ion electrode for rechargeable lithium cell

Science.gov (United States)

Huang, Chen-Kuo (Inventor); Surampudi, Subbarao (Inventor); Attia, Alan I. (Inventor); Halpert, Gerald (Inventor)

1995-01-01

The method includes steps for forming a carbon electrode composed of graphitic carbon particles adhered by an ethylene propylene diene monomer binder. An effective binder composition is disclosed for achieving a carbon electrode capable of subsequent intercalation by lithium ions. The method also includes steps for reacting the carbon electrode with lithium ions to incorporate lithium ions into graphitic carbon particles of the electrode. An electrical current is repeatedly applied to the carbon electrode to initially cause a surface reaction between the lithium ions and to the carbon and subsequently cause intercalation of the lithium ions into crystalline layers of the graphitic carbon particles. With repeated application of the electrical current, intercalation is achieved to near a theoretical maximum. Two differing multi-stage intercalation processes are disclosed. In the first, a fixed current is reapplied. In the second, a high current is initially applied, followed by a single subsequent lower current stage. Resulting carbon/lithium-ion electrodes are well suited for use as an anode in a reversible, ambient temperature, lithium cell.

Electron beam ion trap bi-annual report 1996/1997

International Nuclear Information System (INIS)

Schneider, D.

1999-01-01

The research of the EBIT (Electron Beam Ion Trap) program in N Division of the Physics and Space Technology Directorate at LLNL continues to contribute significantly to the understanding of physical processes with low energy highly charged ions in atomic physics, plasma physics, and material science. Low-energy highly charged ions (up to U 92+ ), provided by the EBIT facilities, provide a unique laboratory opportunity to study high field effects in atomic structures and dynamic interaction processes. The formation, existence, and structure of highly charged ions in astrophysical environments and laboratory plasmas make highly charged ions desirable for diagnosing various plasma conditions. The strong interaction of highly charged ions with matter and the response of solid surfaces make them a sensitive analysis tool and possibly a future capability for materials modifications at the atomic scale (nano technology). These physical applications require a good understanding and careful study of the dynamics of the interactions of the ions with complex systems. The EBIT group hosted an international conference and a workshop on trapped charged particles. The various talks and discussions showed that physics research with trapped charged particles is a very active and attractive area of innovative research, and provides a basis for research efforts in new areas. It also became obvious that the EBIT/RETRAP project has unique capabilities to perform important new experiments with trapped very highly charged ions at rest, which are complementary to and competitive with research at heavy ion storage rings and other trapping facilities planned or in operation in Europe, Japan, and the United States. Atomic structure research at EBIT provides ever better and more experimental complete benchmark data, supplying data needed to improve atomic theories. Research highlights through 1996 and 1997 include hyperfine structure measurements in H-like ions, QED studies, lifetime and

Quantum information processing with trapped ions

International Nuclear Information System (INIS)

Haeffner, H.; Haensel, W.; Rapol, U.; Koerber, T.; Benhelm, J.; Riebe, M.; Chek-al-Kar, D.; Schmidt-Kaler, F.; Becher, C.; Roos, C.; Blatt, R.

2005-01-01

Single Ca + ions and crystals of Ca + ions are confined in a linear Paul trap and are investigated for quantum information processing. Here we report on recent experimental advancements towards a quantum computer with such a system. Laser-cooled trapped ions are ideally suited systems for the investigation and implementation of quantum information processing as one can gain almost complete control over their internal and external degrees of freedom. The combination of a Paul type ion trap with laser cooling leads to unique properties of trapped cold ions, such as control of the motional state down to the zero-point of the trapping potential, a high degree of isolation from the environment and thus a very long time available for manipulations and interactions at the quantum level. The very same properties make single trapped atoms and ions well suited for storing quantum information in long lived internal states, e.g. by encoding a quantum bit (qubit) of information within the coherent superposition of the S 1/2 ground state and the metastable D 5/2 excited state of Ca + . Recently we have achieved the implementation of simple algorithms with up to 3 qubits on an ion-trap quantum computer. We will report on methods to implement single qubit rotations, the realization of a two-qubit universal quantum gate (Cirac-Zoller CNOT-gate), the deterministic generation of multi-particle entangled states (GHZ- and W-states), their full tomographic reconstruction, the realization of deterministic quantum teleportation, its quantum process tomography and the encoding of quantum information in decoherence-free subspaces with coherence times exceeding 20 seconds. (author)

Sawtooth activity of the ion cloud in an electron-beam ion trap

International Nuclear Information System (INIS)

Radtke, R.; Biedermann, C.

2003-01-01

The dynamics of an ensemble of highly charged Ar and Ba ions in an electron-beam ion trap (EBIT) was studied by recording time-resolved x-ray spectra emitted from trapped ions. Sawtoothlike signatures manifest in the spectra for a variety of EBIT operating conditions indicating a sudden collapse of the ion inventory in the trap. The collapse occurs on a time scale of approximately 100 ms and the evolution of the sawteeth is very sensitive to parameters such as electron-beam current and axial trap depth. Analysis of the measurements is based on a time-dependent calculation of the trapping process showing that sawtooth activity is caused by the feedback between the low-Z argon and high-Z barium ions. This unexpected behavior demonstrates the importance of nonlinear effects in electron-beam traps containing more than a single ion species

Quantum computing with trapped ions

Energy Technology Data Exchange (ETDEWEB)

Hughes, R.J.

1998-01-01

The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

Trapped ion depletion by anomalous diffusion due to the dissipative trapped ion instability

International Nuclear Information System (INIS)

Wimmel, H.K.

1975-07-01

At high temperatures the KADOMTSEV-POGUTSE diffusion in tokamaks can become so large as to cause depletion of trapped ions if these are replaced with free ions by means of collisions rather than being directly recycled or injected. Modified KADOMTSEV-POGUTSE diffusion formulas are employed in order to estimate this effect in the cases of classical and anomalous collisions. The maximum trapped-ion depletion is estimated from the PENROSE stability condition. For anomalous collisions a BOHM-type diffusion is derived. Numerical examples are given for JET-like parameters (JET = Joint European Torus). Depletion is found to reduce diffusion by factors of up to 10 and more. (orig.) [de

In-depth study of in-trap high-resolution mass separation by transversal ion ejection from a multi-reflection time-of-flight device.

Science.gov (United States)

Fischer, Paul; Knauer, Stefan; Marx, Gerrit; Schweikhard, Lutz

2018-01-01

The recently introduced method of ion separation by transversal ejection of unwanted species in electrostatic ion-beam traps and multi-reflection time-of-flight devices has been further studied in detail. As this separation is performed during the ion storage itself, there is no need for additional external devices such as ion gates or traps for either pre- or postselection of the ions of interest. The ejection of unwanted contaminant ions is performed by appropriate pulses of the potentials of deflector electrodes. These segmented ring electrodes are located off-center in the trap, i.e., between one of the two ion mirrors and the central drift tube, which also serves as a potential lift for capturing incoming ions and axially ejecting ions of interest after their selection. The various parameters affecting the selection effectivity and resolving power are illustrated with tin-cluster measurements, where isotopologue ion species provide mass differences down to a single atomic mass unit at ion masses of several hundred. Symmetric deflection voltages of only 10 V were found sufficient for the transversal ejection of ion species with as few as three deflection pulses. The duty cycle, i.e., the pulse duration with respect to the period of ion revolution, has been varied, resulting in resolving powers of up to several tens of thousands for this selection technique.

Trapped Ion Qubits

Energy Technology Data Exchange (ETDEWEB)

Maunz, Peter Lukas Wilhelm

2017-04-01

Qubits can be encoded in clock states of trapped ions. These states are well isolated from the environment resulting in long coherence times [1] while enabling efficient high-fidelity qubit interactions mediated by the Coulomb coupled motion of the ions in the trap. Quantum states can be prepared with high fidelity and measured efficiently using fluorescence detection. State preparation and detection with 99.93% fidelity have been realized in multiple systems [1,2]. Single qubit gates have been demonstrated below rigorous fault-tolerance thresholds [1,3]. Two qubit gates have been realized with more than 99.9% fidelity [4,5]. Quantum algorithms have been demonstrated on systems of 5 to 15 qubits [6–8].

Ion Trap Quantum Computing

Science.gov (United States)

2011-12-01

variations of ion traps, including (1) the cylindrically symmetric 3D ring trap; (2) the linear trap with a combination of cavity QED; (#) the symmetric...concepts of quantum information. The major demonstration has been the test of a Bell inequality as demonstrated by Rowe et al. [50] and a decoherence...famous physics experiment [62]. Wolfgang Paul demonstrated a similar apparatus during his Nobel Prize speech [63]. This device is hyperbolic- parabolic

Towards a wire-mediated coupling of trapped ions

Science.gov (United States)

Clark, Robert; Lee, Tony; Daniilidis, Nikos; Sankaranarayanan, S.; Häffner, Hartmut

2008-03-01

Most schemes for ion trap quantum computation rely upon the exchange of information between ion-qubits in the same trap region, mediated by their shared vibrational mode. An alternative way to achieve this coupling is via the image charges induced in a conducting wire that connects different traps. This was shown to be theoretically possible by Heinzen and Wineland in 1990, but some important practical questions have remained unaddressed. Among these are how the presence of such a wire modifies the motional frequencies and heating rates of trapped ions. We thus have realized this system as a 1 mm-scale planar segmented rf ion trap combined with an electrically floating gold wire of 25 microns diameter and length 1 cm. This wire is placed close to trapped ions using a set of piezoelectric nanopositioners. We present here experimental measurements of the motional frequencies and heating rates of a single trapped calcium ion as the wire is moved from 3.0 mm to 0.2 mm away from the ion. We discuss the implications of these results for achieving wire-mediated coupling in the present apparatus, as well as in future improved setups.

EBIT (Electron Beam Ion Trap), N-Division Experimental Physics. Annual report, 1994

International Nuclear Information System (INIS)

Schneider, D.

1995-10-01

The experimental groups in the Electron Beam Ion Trap (EBIT) program continue to perform front-line research with trapped and extracted highly charged ions (HCI) in the areas of ion/surface interactions, atomic spectroscopy, electron-ion interaction and structure measurements, highly charged ion confinement, and EBIT development studies. The ion surface/interaction studies which were initiated five years ago have reached a stage where they an carry out routine investigations, as well as produce breakthrough results towards the development of novel nanotechnology. At EBIT and SuperEBIT studies of the x-ray emission from trapped ions continue to produce significant atomic structure data with high precision for few electron systems of high-Z ions. Furthermore, diagnostics development for magnetic and laser fusion, supporting research for the x-ray laser and weapons programs, and laboratory astrophysics experiments in support of NASA's astrophysics program are a continuing effort. The two-electron contributions to the binding energy of helium like ions were measured for the first time. The results are significant because their precision is an order of magnitude better than those of competing measurements at accelerators, and the novel technique isolates the energy corrections that are the most interesting. The RETRAP project which was initiated three years ago has reached a stage where trapping, confining and electronic cooling of HCI ions up to Th 80+ can be performed routinely. Measurements of the rates and cross sections for electron transfer from H 2 performed to determine the lifetime of HCI up to Xe q+ and Th q+ (35 ≤ q ≤ 80) have been studied at mean energies estimated to be ∼ 5 q eV. This combination of heavy ions with very high charges and very low energies is rare in nature, but may be encountered in planned fusion energy demonstration devices, in highly charged ion sources, or in certain astrophysical events

A model for crack initiation in the Li-ion battery electrodes

Energy Technology Data Exchange (ETDEWEB)

Panat, Rahul, E-mail: rahul.panat@wsu.edu

2015-12-01

The development of high energy density Lithium-ion batteries is of intense interest due to their application in the electric car and consumer electronics industry. The primary limiter in using high energy density battery electrodes is the cracking of the electrode material due to the severe strain caused by the charging–discharging cycles. In this paper, a linear perturbation model is used to describe the evolution of the electrode surface under stress. The driving force for the surface undulation formation is the reduction in the electrode strain energy. The kinetics of mass transport is described by the surface and volume diffusion. The model predicts that the Si electrode will develop surface undulations of the order of sub-1 μm length scale on the electrode surface, showing a reasonable agreement with experimental results reported in literature. Such surface undulations roughen the anode surface and can form notches that can act as crack initiation sites. It is also shown that this model is applicable when the temperature of the system is not constant and the system is not isolated. The limitations of the model are also discussed. - Highlights: • This work presents a theoretical formulation that predicts crack formation at an electrode surface under a lithiation cycle. • The research provides the critical parameters required to improve the life of the Li-ion batteries. • These research findings can be used to modify the surface structure to minimize crack formation. • The predictions from the model show a reasonable agreement with the experiments. • None of the theoretical literature so far has addressed the crack formation problem addressed in this paper.

Highly charged ion trapping and cooling

International Nuclear Information System (INIS)

Beck, B. R.; Church, D. A.; Gruber, L.; Holder, J. P.; Schneider, D.; Steiger, J.

1998-01-01

In the past few years a cryogenic Penning trap (RETRAP) has been operational at the Electron Beam Ion Trap (EBIT) facility at Lawrence Livermore National Laboratory. The combination of RETRAP and EBIT provides a unique possibility of producing and re-trapping highly charged ions and cooling them to very low temperatures. Due to the high Coulomb potentials in such an ensemble of cold highly charged ions the Coulomb coupling parameter (the ratio of Coulomb potential to the thermal energy) can easily reach values of 172 and more. To study such systems is not only of interest in astrophysics to simulate White Dwarf star interiors but opens up new possibilities in a variety of areas (e.g. laser spectroscopy), cold highly charged ion beams

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

International Nuclear Information System (INIS)

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

1977-01-01

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

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

International Nuclear Information System (INIS)

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

1986-01-01

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

Ion dynamics in porous carbon electrodes in supercapacitors using in situ infrared spectroelectrochemistry.

Science.gov (United States)

Richey, Francis W; Dyatkin, Boris; Gogotsi, Yury; Elabd, Yossef A

2013-08-28

Electrochemical double layer capacitors (EDLCs), or supercapacitors, rely on electrosorption of ions by porous carbon electrodes and offer a higher power and a longer cyclic lifetime compared to batteries. Ionic liquid (IL) electrolytes can broaden the operating voltage window and increase the energy density of EDLCs. Herein, we present direct measurements of the ion dynamics of 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide in an operating EDLC with electrodes composed of porous nanosized carbide-derived carbons (CDCs) and nonporous onion-like carbons (OLCs) with the use of in situ infrared spectroelectrochemistry. For CDC electrodes, IL ions (both cations and anions) were directly observed entering and exiting CDC nanopores during charging and discharging of the EDLC. Conversely, for OLC electrodes, IL ions were observed in close proximity to the OLC surface without any change in the bulk electrolyte concentration during charging and discharging of the EDLC. This provides experimental evidence that charge is stored on the surface of OLCs in OLC EDLCs without long-range ion transport through the bulk electrode. In addition, for CDC EDLCs with mixed electrolytes of IL and propylene carbonate (PC), the IL ions were observed entering and exiting CDC nanopores, while PC entrance into the nanopores was IL concentration dependent. This work provides direct experimental confirmation of EDLC charging mechanisms that previously were restricted to computational simulations and theories. The experimental measurements presented here also provide deep insights into the molecular level transport of IL ions in EDLC electrodes that will impact the design of the electrode materials' structure for electrical energy storage.

Space-charge effects in Penning ion traps

Science.gov (United States)

Porobić, T.; Beck, M.; Breitenfeldt, M.; Couratin, C.; Finlay, P.; Knecht, A.; Fabian, X.; Friedag, P.; Fléchard, X.; Liénard, E.; Ban, G.; Zákoucký, D.; Soti, G.; Van Gorp, S.; Weinheimer, Ch.; Wursten, E.; Severijns, N.

2015-06-01

The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with K39+ using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations.

Implementation schemes for unsharp measurements with trapped ions

CSIR Research Space (South Africa)

Choudhary, SK

2013-01-01

Full Text Available trapped ion. The schemes rely on introducing weak entanglement between the state of a target ion and that of an auxiliary ion, using standard ion-trap quantum logic operations, and then realizing an unsharp measurement through projective measurement...

Ion-selective electrodes

CERN Document Server

Mikhelson, Konstantin N

2013-01-01

Ion-selective electrodes (ISEs) have a wide range of applications in clinical, environmental, food and pharmaceutical analysis as well as further uses in chemistry and life sciences. Based on his profound experience as a researcher in ISEs and a course instructor, the author summarizes current knowledge for advanced teaching and training purposes with a particular focus on ionophore-based ISEs. Coverage includes the basics of measuring with ISEs, essential membrane potential theory and a comprehensive overview of the various classes of ion-selective electrodes. The principles of constructing I

The Penning trap system used by the BASE experiment

CERN Multimedia

Marcastel, Fabienne

2015-01-01

A cut-away schematic of the Penning trap system used by BASE. The experiment receives antiprotons from CERN's AD; negative hydrogen ions are formed during injection into the apparatus. The set-up works with only a pair of particles at a time, while a cloud of a few hundred others are held in the reservoir trap, for future use. Here, an antiproton is in the measurement trap, while the negative hydyrogen ion is in held by the downstream park electrode. When the antiproton has been measured, it is moved to the upstream park electrode and the hydrogen ion is brought in to the measurement trap. This is repeated thousands of times, enabling a high-precision comparison of the charge-to-mass ratios of the two particles.

Optimization of polymeric triiodide membrane electrode based on clozapine-triiodide ion-pair using experimental design.

Science.gov (United States)

Farhadi, Khalil; Bahram, Morteza; Shokatynia, Donya; Salehiyan, Floria

2008-07-15

Central composite design (CCD) and response surface methodology (RSM) were developed as experimental strategies for modeling and optimization of the influence of some variables on the performance of a new PVC membrane triiodide ion-selective electrode. This triiodide sensor is based on triiodide-clozapine ion-pair complexation. PVC, plasticizers, ion-pair amounts and pH were investigated as four variables to build a model to achieve the best Nernstian slope (59.9 mV) as response. The electrode is prepared by incorporating the ion-exchanger in PVC matrix plasticized with 2-nitrophenyl octal ether, which is directly coated on the surface of a graphite electrode. The influence of foreign ions on the electrode performance was also investigated. The optimized membranes demonstrate Nernstian response for triiodide ions over a wide linear range from 5.0 x 10(-6) to 1.0 x 10(-2)mol L(-1) with a limit of detection 2.0 x 10(-6) mol L(-1) at 25 degrees C. The electrodes could be used over a wide pH range 4-8, and have the advantages of easy to prepare, good selectivity and fast response time, long lifetime (over 3 months) and small interferences from hydrogen ion. The proposed electrode was successfully used as indicator electrode in potentiometric titration of triiodide ions and ascorbic acid.

Negative electrodes for Na-ion batteries.

Science.gov (United States)

Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

2014-08-07

Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

Solvent-Free Manufacturing of Electrodes for Lithium-ion Batteries

Science.gov (United States)

Ludwig, Brandon; Zheng, Zhangfeng; Shou, Wan; Wang, Yan; Pan, Heng

2016-03-01

Lithium ion battery electrodes were manufactured using a new, completely dry powder painting process. The solvents used for conventional slurry-cast electrodes have been completely removed. Thermal activation time has been greatly reduced due to the time and resource demanding solvent evaporation process needed with slurry-cast electrode manufacturing being replaced by a hot rolling process. It has been found that thermal activation time to induce mechanical bonding of the thermoplastic polymer to the remaining active electrode particles is only a few seconds. Removing the solvent and drying process allows large-scale Li-ion battery production to be more economically viable in markets such as automotive energy storage systems. By understanding the surface energies of various powders which govern the powder mixing and binder distribution, bonding tests of the dry-deposited particles onto the current collector show that the bonding strength is greater than slurry-cast electrodes, 148.8 kPa as compared to 84.3 kPa. Electrochemical tests show that the new electrodes outperform conventional slurry processed electrodes, which is due to different binder distribution.

Ion bunch stacking in a Penning trap after purification in an electrostatic mirror trap

CERN Document Server

Rosenbusch, M; Blaum, K; Borgmann, Ch; Kreim, S; Lunney, D; Manea, V; Schweikhard, L; Wienholtz, F; Wolf, R N

2014-01-01

The success of many measurements in analytical mass spectrometry as well as in precision mass determinations for atomic and nuclear physics is handicapped when the ion sources deliver ``contaminations'', i.e., unwanted ions of masses similar to those of the ions of interest. In particular, in ion-trapping devices, large amounts of contaminant ions result in significant systematic errors-if the measurements are possible at all. We present a solution for such cases: The ions from a quasi-continuous source are bunched in a linear radio-frequency-quadrupole ion trap, separated by a multi-reflection time-of-flight section followed by a Bradbury-Nielsen gate, and then captured in a Penning trap. Buffer-gas cooling is used to damp the ion motion in the latter, which allows a repeated opening of the Penning trap for a stacking of mass-selected ion bunches. Proof-of-principle demonstrations have been performed with the ISOLTRAP setup at ISOLDE/CERN, both with Cs-133(+) ions from an off-line ion source and by applicati...

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

Cryptography, quantum computation and trapped ions

Energy Technology Data Exchange (ETDEWEB)

Hughes, Richard J.

1998-03-01

The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

Evaporative cooling of highly charged ions in EBIT [Electron Beam Ion Trap]: An experimental realization

International Nuclear Information System (INIS)

Schneider, M.B.; Levine, M.A.; Bennett, C.L.; Henderson, J.R.; Knapp, D.A.; Marrs, R.E.

1988-01-01

Both the total number and trapping lifetime of near-neon-like gold ions held in an electron beam ion trap have been greatly increased by a process of 'evaporative cooling'. A continuous flow of low-charge-state ions into the trap cools the high-charge-state ions in the trap. Preliminary experimental results using titanium ions as a coolant are presented. 8 refs., 6 figs., 2 tabs

Ion-selective electrodes

Energy Technology Data Exchange (ETDEWEB)

Mikhelson, Konstantin N. [St. Petersburg State Univ. (Russian Federation). Ion-Selective Electrode Laboratory

2013-06-01

Ion-selective electrodes (ISEs) have a wide range of applications in clinical, environmental, food and pharmaceutical analysis as well as further uses in chemistry and life sciences. Based on his profound experience as a researcher in ISEs and a course instructor, the author summarizes current knowledge for advanced teaching and training purposes with a particular focus on ionophore-based ISEs. Coverage includes the basics of measuring with ISEs, essential membrane potential theory and a comprehensive overview of the various classes of ion-selective electrodes. The principles of constructing ISEs are outlined, and the transfer of methods into routine analysis is considered.

EBIT (Electron Beam Ion Trap), N-Division Experimental Physics. Annual report, 1994

Energy Technology Data Exchange (ETDEWEB)

Schneider, D. [ed.

1995-10-01

The experimental groups in the Electron Beam Ion Trap (EBIT) program continue to perform front-line research with trapped and extracted highly charged ions (HCI) in the areas of ion/surface interactions, atomic spectroscopy, electron-ion interaction and structure measurements, highly charged ion confinement, and EBIT development studies. The ion surface/interaction studies which were initiated five years ago have reached a stage where they an carry out routine investigations, as well as produce breakthrough results towards the development of novel nanotechnology. At EBIT and SuperEBIT studies of the x-ray emission from trapped ions continue to produce significant atomic structure data with high precision for few electron systems of high-Z ions. Furthermore, diagnostics development for magnetic and laser fusion, supporting research for the x-ray laser and weapons programs, and laboratory astrophysics experiments in support of NASA`s astrophysics program are a continuing effort. The two-electron contributions to the binding energy of helium like ions were measured for the first time. The results are significant because their precision is an order of magnitude better than those of competing measurements at accelerators, and the novel technique isolates the energy corrections that are the most interesting. The RETRAP project which was initiated three years ago has reached a stage where trapping, confining and electronic cooling of HCI ions up to Th{sup 80+} can be performed routinely. Measurements of the rates and cross sections for electron transfer from H{sub 2} performed to determine the lifetime of HCI up to Xe{sup q+} and Th{sup q+} (35 {le} q {le} 80) have been studied at mean energies estimated to be {approximately} 5 q eV. This combination of heavy ions with very high charges and very low energies is rare in nature, but may be encountered in planned fusion energy demonstration devices, in highly charged ion sources, or in certain astrophysical events.

Ion trapping within the dust grain plasma sheath

International Nuclear Information System (INIS)

Jovanovic, D.; Shukla, P.K.

2002-01-01

One of the most important and still unresolved problems in the physics of dusty plasmas is the determination of the dust charge. The grains are not directly accessible to measurements and it is necessary to have a reliable theoretical model of the electron and ion dynamics inside the Debye sphere for the interpretation of the relevant experimental data, which include also the effects of the surrounding electron and ion clouds. Recent computer simulations [6] and laboratory experiments [9] indicate that the plasma sheath is dominated by trapped ions, orbiting the grain on closed trajectories at distances smaller than the Debye radius, that cannot be accounted for by the classical theories. We present the first analytical, fully self-consistent, calculations of the electrostatic shielding of a charged dust grain in a collisional plasma. In the regime when the mean free path for the ion-dust collisions is larger than that for the ion-neutral collisions, we solve the kinetic equation for the ions, coupled with Boltzmann distributed electrons and Poisson's equation. The ion velocity distribution function, in the form of a spherically symmetric ion hole, is found to be anisotropic in the presence of charge-exchange collisions. The number of trapped ions and their spatial distribution are determined from the interplay between the collective plasma interaction and the collisional trapping/de-trapping. The stationary state results from the self-tuning of the trapped ion density by the feedback based on the nonlocality of the collisional integral, and on the ion mixing in the radial direction along elongated orbits. Our results confirm the existence of a strong Debye shielding of the dust charge, allowing also the over-population of the trapped ion distribution (ion hump)

A small trapped-ion quantum register

International Nuclear Information System (INIS)

Kielpinski, D

2003-01-01

We review experiments performed at the National Institute of Standards and Technology on entanglement, Bell's inequality and decoherence-free subspaces (DFSs) in a quantum register of trapped 9 Be + ions. The group of Dr David Wineland has demonstrated entanglement of up to four ions using the technique of Molmer and Sorensen. This method produces the state (|↓↓> + |↑↑>)/√2 for two ions and the state (|↓↓↓↓> + |↑↑↑↑>)/√2 for four ions. The entanglement was generated deterministically in each shot of the experiment. Measurements on the two-ion entangled state violate Bell's inequality at the 8σ level. Because of the high detector efficiency of the apparatus, this experiment closes the detector loophole for Bell's inequality measurements for the first time. This measurement is also the first violation of Bell's inequality by massive particles that does not implicitly assume results from quantum mechanics. The group also demonstrated measurement of an interferometric phase with precision better than the shot-noise limit using a two-ion entangled state. A large-scale version of this scheme could improve the signal-to-noise ratio of atomic clocks by orders of magnitude. Further experiments demonstrated reversible encoding of an arbitrary qubit, originally contained in one ion, into a DFS of two ions. The DFS-encoded qubit resists applied collective dephasing noise and retains coherence under ambient conditions 3.6 times longer than does an unencoded qubit. The encoding method, which uses single-ion gates and the two-ion entangling gate, demonstrates all the elements required for two-qubit universal quantum logic. Finally, we describe an architecture for a large-scale ion trap quantum computer. By performing logic gates on small numbers of ions trapped in separate regions of the array, we take advantage of existing techniques for manipulating small trapped-ion quantum registers while enabling massively parallel gate operation. Encoding the

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

International Nuclear Information System (INIS)

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

1983-01-01

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

Modular Universal Scalable Ion-trap Quantum Computer

Science.gov (United States)

2016-06-02

SECURITY CLASSIFICATION OF: The main goal of the original MUSIQC proposal was to construct and demonstrate a modular and universally- expandable ion...Distribution Unlimited UU UU UU UU 02-06-2016 1-Aug-2010 31-Jan-2016 Final Report: Modular Universal Scalable Ion-trap Quantum Computer The views...P.O. Box 12211 Research Triangle Park, NC 27709-2211 Ion trap quantum computation, scalable modular architectures REPORT DOCUMENTATION PAGE 11

Recovery of fluoride ion selective electrode

International Nuclear Information System (INIS)

Monteiro, R.P.G.

1988-01-01

A recovery procedure of fluoride ion selective electrode based upon the body radiography of inactive electrode and introduction of suitable internal regeneration solution, is developed. The recovered electrode was tested in standard solutions of fluoride ions (10 sup5) to 10 -1M showing as good performance as the new one. The fluor determination by potentiometric measurements with selective electrode is used in nuclear fuel cycle for quality control of thorium and uranium mixed oxide pellets and pellets of uranium dioxides. (author) [pt

Surface functional groups in capacitive deionization with porous carbon electrodes

Science.gov (United States)

Hemmatifar, Ali; Oyarzun, Diego I.; Palko, James W.; Hawks, Steven A.; Stadermann, Michael; Santiago, Juan G.; Stanford Microfluidics Lab Team; Lawrence Livermore National Lab Team

2017-11-01

Capacitive deionization (CDI) is a promising technology for removal of toxic ions and salt from water. In CDI, an applied potential of about 1 V to pairs of porous electrodes (e.g. activated carbon) induces ion electromigration and electrostatic adsorption at electrode surfaces. Immobile surface functional groups play a critical role in the type and capacity of ion adsorption, and this can dramatically change desalination performance. We here use models and experiments to study weak electrolyte surface groups which protonate and/or depropotante based on their acid/base dissociation constants and local pore pH. Net chemical surface charge and differential capacitance can thus vary during CDI operation. In this work, we present a CDI model based on weak electrolyte acid/base equilibria theory. Our model incorporates preferential cation (anion) adsorption for activated carbon with acidic (basic) surface groups. We validated our model with experiments on custom built CDI cells with a variety of functionalizations. To this end, we varied electrolyte pH and measured adsorption of individual anionic and cationic ions using inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography (IC) techniques. Our model shows good agreement with experiments and provides a framework useful in the design of CDI control schemes.

Selective passive adsorption of nitrate with surfactant treated porous electrode and electrostatic regeneration

Science.gov (United States)

Oyarzun, Diego I.; Hemmatifar, Ali; Palko, James W.; Stadermann, Michael; Santiago, Juan G.; Stanford microfluidics lab Team; Lawrence Livermore National Lab Team

2017-11-01

Nitrate is an important pollutant in drinking water worldwide, and a number of methods exist for the removal of nitrate from water including ion exchange and reverse osmosis. However, these approaches suffer from a variety of disadvantages including the need for a regenerating brine supply and disposal of used brine for ion exchange and low water recovery ratio for reverse osmosis. We are researching and developing a form of capacitive deionization (CDI) for energy efficient desalination and selective removal of ionic toxins from water. In CDI an electrode is used to electrostatically trap ions in a pair of porous electrodes. Here, we demonstrate the use of high surface area activated carbon electrodes functionalized with ion exchange moieties for adsorption of nitrate from aqueous solution. Unlike a traditional ion exchanger, the functionalized surfaces can be repeatedly regenerated by the application of an electrostatic potential which displaces the bound NO3- while leaving an excess of electronic charge on the electrode. Trimethylammonium has an intrinsic selectivity, we are using this moiety to selectively remove nitrate over chloride. We performed adsorption/desorption cycles under several desorption voltages and ratios of concentrations.

Hydrogen substituted graphdiyne as carbon-rich flexible electrode for lithium and sodium ion batteries.

Science.gov (United States)

He, Jianjiang; Wang, Ning; Cui, Zili; Du, Huiping; Fu, Lin; Huang, Changshui; Yang, Ze; Shen, Xiangyan; Yi, Yuanping; Tu, Zeyi; Li, Yuliang

2017-10-27

Organic electrodes are potential alternatives to current inorganic electrode materials for lithium ion and sodium ion batteries powering portable and wearable electronics, in terms of their mechanical flexibility, function tunability and low cost. However, the low capacity, poor rate performance and rapid capacity degradation impede their practical application. Here, we concentrate on the molecular design for improved conductivity and capacity, and favorable bulk ion transport. Through an in situ cross-coupling reaction of triethynylbenzene on copper foil, the carbon-rich frame hydrogen substituted graphdiyne film is fabricated. The organic film can act as free-standing flexible electrode for both lithium ion and sodium ion batteries, and large reversible capacities of 1050 mAh g -1 for lithium ion batteries and 650 mAh g -1 for sodium ion batteries are achieved. The electrode also shows a superior rate and cycle performances owing to the extended π-conjugated system, and the hierarchical pore bulk with large surface area.

Determination of Mercury (II Ion on Aryl Amide-Type Podand-Modified Glassy Carbon Electrode

Directory of Open Access Journals (Sweden)

Sevgi Güney

2011-01-01

Full Text Available A new voltammetric sensor based on an aryl amide type podand, 1,8-bis(o-amidophenoxy-3,6-dioxaoctane, (AAP modified glassy carbon electrode, was described for the determination of trace level of mercury (II ion by cyclic voltammetry (CV and differential pulse voltammetry (DPV. A well-defined anodic peak corresponding to the oxidation of mercury on proposed electrode was obtained at 0.2 V versus Ag/AgCl reference electrode. The effect of experimental parameters on differential voltammetric peak currents was investigated in acetate buffer solution of pH 7.0 containing 1 × 10−1 mol L−1 NaCl. Mercury (II ion was preconcentrated at the modified electrode by forming complex with AAP under proper conditions and then reduced on the surface of the electrode. Interferences of Cu2+, Pb2+, Fe3+, Cd2+, and Zn2+ ions were also studied at two different concentration ratios with respect to mercury (II ions. The modified electrode was applied to the determination of mercury (II ions in seawater sample.

Space-charge effects in Penning ion traps

Czech Academy of Sciences Publication Activity Database

Porobic, T.; Beck, M.; Breitenfeldt, M.; Couratin, C.; Finlay, P.; Knecht, A.; Fabian, X.; Friedag, P.; Flechard, X.; Lienard, E.; Ban, G.; Zákoucký, Dalibor; Soti, G.; Van Gorp, S.; Weinheimer, C.; Wursten, E.; Severijns, N.

2015-01-01

Roč. 785, JUN (2015), s. 153-162 ISSN 0168-9002 R&D Projects: GA MŠk LA08015; GA MŠk(CZ) LG13031 Institutional support: RVO:61389005 Keywords : Penning trap * space-charge * magnetron motion * ion trapping * buffer gas cooling * ion cyclotron resonance Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.200, year: 2015

Electrodynamically trapped Yb+ ions for quantum information processing

International Nuclear Information System (INIS)

Balzer, Chr.; Braun, A.; Hannemann, T.; Wunderlich, Chr.; Paape, Chr.; Ettler, M.; Neuhauser, W.

2006-01-01

Highly efficient, nearly deterministic, and isotope selective generation of Yb + ions by one- and two-color photoionization is demonstrated. State preparation and state selective detection of hyperfine states in 171 Yb + is investigated in order to optimize the purity of the prepared state and to time-optimize the detection process. Linear laser-cooled Yb + ion crystals confined in a Paul trap are demonstrated. Advantageous features of different previous ion trap experiments are combined, while at the same time the number of possible error sources is reduced by using a comparatively simple experimental apparatus. This opens a new path toward quantum state manipulation of individual trapped ions, and in particular, to scalable quantum computing

Negative-ion current density dependence of the surface potential of insulated electrode during negative-ion implantation

International Nuclear Information System (INIS)

Tsuji, Hiroshi; Okayama, Yoshio; Toyota, Yoshitaka; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki; Tanjyo, Masayasu; Matsuda, Kouji.

1994-01-01

Positive ion implantation has been utilized as the method of impurity injection in ultra-LSI production, but the problem of substrate charging cannot be resolved by conventional charge compensation method. It was forecast that by negative ion implantation, this charging problem can be resolved. Recently the experiment on the negative ion implantation into insulated electrodes was carried out, and the effect of negative ion implantation to this problem was proved. However, the dependence of charged potential on the increase of negative ion current at the time of negative ion implantation is a serious problem in large current negative ion implantation hereafter. The charged potential of insulated conductor substrates was measured by the negative ion implantation using the current up to several mA/cm 2 . The experimental method is explained. Medium current density and high current density negative ion implantation and charged potential are reported. Accordingly in negative ion implantation, if current density is optimized, the negative ion implantation without charging can be realized. (K.I.)

Scalable error correction in distributed ion trap computers

International Nuclear Information System (INIS)

Oi, Daniel K. L.; Devitt, Simon J.; Hollenberg, Lloyd C. L.

2006-01-01

A major challenge for quantum computation in ion trap systems is scalable integration of error correction and fault tolerance. We analyze a distributed architecture with rapid high-fidelity local control within nodes and entangled links between nodes alleviating long-distance transport. We demonstrate fault-tolerant operator measurements which are used for error correction and nonlocal gates. This scheme is readily applied to linear ion traps which cannot be scaled up beyond a few ions per individual trap but which have access to a probabilistic entanglement mechanism. A proof-of-concept system is presented which is within the reach of current experiment

Resistive interchange mode destabilized by helically trapped energetic ions and its effects on energetic ions and bulk plasmas

International Nuclear Information System (INIS)

Du, X.D.; Toi, K.; Osakabe, M.

2014-10-01

A resistive interchange mode with bursting behavior and rapid frequency chirping in the range less than 10 kHz is observed for the first time in the magnetic hill region of net current-free, low beta LHD (Large Helical Device) plasmas during high power injection of perpendicular neutral beams. The mode resonates with the precession motion of helically trapped energetic beam ions, following the resonant condition. The radial mode structure is found to be very similar to that of usual pressure-driven interchange mode, of which radial displacement eigenfunction has an even function around the rational surface. This beam driven mode is excited when the beta value of helically trapped energetic ions exceed a certain threshold. The radial transport of helically trapped energetic ions induced by the mode transiently generates significant radial electric field near the plasma peripheral region. Thus generated radial electric field clearly suppresses micro turbulence and improves bulk plasma confinement, suggesting strong flow shear generation. (author)

Frequency-scanning MALDI linear ion trap mass spectrometer for large biomolecular ion detection.

Science.gov (United States)

Lu, I-Chung; Lin, Jung Lee; Lai, Szu-Hsueh; Chen, Chung-Hsuan

2011-11-01

This study presents the first report on the development of a matrix-assisted laser desorption ionization (MALDI) linear ion trap mass spectrometer for large biomolecular ion detection by frequency scan. We designed, installed, and tested this radio frequency (RF) scan linear ion trap mass spectrometer and its associated electronics to dramatically extend the mass region to be detected. The RF circuit can be adjusted from 300 to 10 kHz with a set of operation amplifiers. To trap the ions produced by MALDI, a high pressure of helium buffer gas was employed to quench extra kinetic energy of the heavy ions produced by MALDI. The successful detection of the singly charged secretory immunoglobulin A ions indicates that the detectable mass-to-charge ratio (m/z) of this system can reach ~385 000 or beyond.

Ammonium ions determination with polypyrrole modified electrode

Directory of Open Access Journals (Sweden)

Luiz Henrique Dall´Antonia

2007-03-01

Full Text Available The present work relates the preparation of polypyrrole films (PPy deposited on surfaces of glass carbon, nickel and ITO (tin oxide doped with indium on PET plastic, in order to study the ammonium detection. The popypyrrole films were polymerized with dodecylbenzenesulfonate (DBSA on the electrodes, at + 0,70 V vs. Ag/AgCl, based on a solution containing the pyrrole monomer and the amphiphilic salt. Films deposited on glass carbon presented better performance. Cyclic voltammetries, between – 1,50 to + 0,5 V vs. Ag/AgCl, were repeated adding different concentrations of NH4Cl, in order to observe the behavior of the film as a possible detector of ions NH4+. The peak current for oxidation varies with the concentration of ammonium. A linear region can be observed in the band of 0 to 80 mM, with a sensibility (Sppy approximately similar to 4,2 mA mM-1 cm-2, showing the efficacy of the electrodes as sensors of ammonium ions. The amount of deposited polymer, controlled by the time of growth, does not influence on the sensor sensibility. The modified electrode was used to determine ammonium in grounded waters.

Detecting yocto (10-24) newton forces with trapped ions

CSIR Research Space (South Africa)

Uys, H

2010-09-01

Full Text Available This article reports on a calibrated measurement of 174 Yoctonewton using a cloud of 60 9 Be+ ion confined in a Penning ion trap. These measurements suggest that ion traps may form the basis of a new class of ultrasensitive deployable force sensors....

Vortex trapping in Pb-alloy Josephson junctions induced by strong sputtering of the base electrode

International Nuclear Information System (INIS)

Wada, M.; Nakano, J.; Yanagawa, F.

1985-01-01

It is observed that strong rf sputtering of the Pb-alloy base electrodes causes the junctions to trap magnetic vortices and thus induces Josephson current (I/sub J/) suppression. Trapping begins to occur when the rf sputtering that removes the native thermal oxide on the base electrode is carried out prior to rf plasma oxidation. Observed large I/sub J/ suppression is presumably induced by the concentration of vortices into the sputtered area upon cooling the sample below the transition temperature. This suggests a new method of the circumvention of the vortex trapping by strongly rf sputtering the areas of the electrode other than the junction areas

Two-dimensional analysis of trapped-ion eigenmodes

International Nuclear Information System (INIS)

Marchand, R.; Tang, W.M.; Rewoldt, G.

1979-11-01

A fully two-dimensional eigenmode analysis of the trapped-ion instability in axisymmetric toroidal geometry is presented. The calculations also takes into account the basic dynamics associated with other low frequency modes such as the trapped-electron instability and the ion-temperature-gradient instability. The poloidal structure of the mode is taken into account by Fourier expanding the perturbed electrostatic potential, PHI, in theta

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

International Nuclear Information System (INIS)

Ishikawa, Junzo

1990-01-01

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

Roles of surface chemistry on safety and electrochemistry in lithium ion batteries.

Science.gov (United States)

Lee, Kyu Tae; Jeong, Sookyung; Cho, Jaephil

2013-05-21

Motivated by new applications including electric vehicles and the smart grid, interest in advanced lithium ion batteries has increased significantly over the past decade. Therefore, research in this field has intensified to produce safer devices with better electrochemical performance. Most research has focused on the development of new electrode materials through the optimization of bulk properties such as crystal structure, ionic diffusivity, and electric conductivity. More recently, researchers have also considered the surface properties of electrodes as critical factors for optimizing performance. In particular, the electrolyte decomposition at the electrode surface relates to both a lithium ion battery's electrochemical performance and safety. In this Account, we give an overview of the major developments in the area of surface chemistry for lithium ion batteries. These ideas will provide the basis for the design of advanced electrode materials. Initially, we present a brief background to lithium ion batteries such as major chemical components and reactions that occur in lithium ion batteries. Then, we highlight the role of surface chemistry in the safety of lithium ion batteries. We examine the thermal stability of cathode materials: For example, we discuss the oxygen generation from cathode materials and describe how cells can swell and heat up in response to specific conditions. We also demonstrate how coating the surfaces of electrodes can improve safety. The surface chemistry can also affect the electrochemistry of lithium ion batteries. The surface coating strategy improved the energy density and cycle performance for layered LiCoO2, xLi2MnO3·(1 - x)LiMO2 (M = Mn, Ni, Co, and their combinations), and LiMn2O4 spinel materials, and we describe a working mechanism for these enhancements. Although coating the surfaces of cathodes with inorganic materials such as metal oxides and phosphates improves the electrochemical performance and safety properties of

Cavity QED with single trapped Ca+-ions

International Nuclear Information System (INIS)

Mundt, A.B.

2003-02-01

This thesis reports on the design and setup of a vacuum apparatus allowing the investigation of cavity QED effects with single trapped 40 Ca + ions. The weak coupling of ion and cavity in the 'bad cavity limit' may serve to inter--convert stationary and flying qubits. The ion is confined in a miniaturized Paul trap and cooled via the Doppler effect to the Lamb--Dicke regime. The extent of the atomic wave function is less than 30 nm. The ion is enclosed by a high finesse optical cavity. The technically--involved apparatus allows movement of the trap relative to the cavity and the trapped ion can be placed at any position in the standing wave. By means of a transfer lock the cavity can be resonantly stabilized with the S 1/2 ↔ D 5/2 quadrupole transition at 729 nm (suitable as a qubit) without light at that wavelength being present in the cavity. The coupling of the cavity field to the S 1/2 ↔ D 5/2 quadrupole transition is investigated with various techniques in order to determine the spatial dependence as well as the temporal dynamics. The orthogonal coupling of carrier and first--order sideband transitions at field nodes and antinodes is explored. The coherent interaction of the ion and the cavity field is confirmed by exciting Rabi oscillations with short resonant pulses injected into the cavity. Finally, first experimental steps towards the observation of cavity enhanced spontaneous emission have been taken. (author)

MgO-templated carbon as a negative electrode material for Na-ion capacitors

Science.gov (United States)

Kado, Yuya; Soneda, Yasushi

2016-12-01

In this study, MgO-templated carbon with different pore structures was investigated as a negative electrode material for Na-ion capacitors. With increasing the Brunauer-Emmett-Teller surface area, the irreversible capacity increased, and the coulombic efficiency of the 1st cycle decreased because of the formation of solid electrolyte interface layers. MgO-templated carbon annealed at 1000 °C exhibited the highest capacity and best rate performance, suggesting that an appropriate balance between surface area and crystallinity is imperative for fast Na-ion storage, attributed to the storage mechanism: combination of non-faradaic electric double-layer capacitance and faradaic Na intercalation in the carbon layers. Finally, a Na-ion capacitor cell using MgO-templated carbon and activated carbon as the negative and positive electrodes, respectively, exhibited an energy density at high power density significantly greater than that exhibited by the cell using a commercial hard carbon negative electrode.

Sympathetic Wigner-function tomography of a dark trapped ion

DEFF Research Database (Denmark)

Mirkhalaf, Safoura; Mølmer, Klaus

2012-01-01

A protocol is provided to reconstruct the Wigner function for the motional state of a trapped ion via fluorescence detection on another ion in the same trap. This “sympathetic tomography” of a dark ion without optical transitions suitable for state measurements is based on the mapping of its...

Atomic physics of highly charged ions in an electron beam ion trap

International Nuclear Information System (INIS)

Marrs, R.E.

1990-07-01

Two electron beam ion traps are in use at LLNL for the purpose of studying the properties of very highly charged ions and their interactions with electrons. This paper reviews the operation of the traps and discusses recent experiments in three areas: precision transition energy measurements in the limit of very high ion charge, dielectronic recombination measurements for the He-like isoelectronic sequence, and measurements of x-ray polarization. 22 refs., 11 figs., 1 tab

HITRAP: A Facility for Experiments with Trapped Highly Charged Ions

International Nuclear Information System (INIS)

Quint, W.; Dilling, J.; Djekic, S.; Haeffner, H.; Hermanspahn, N.; Kluge, H.-J.; Marx, G.; Moore, R.; Rodriguez, D.; Schoenfelder, J.; Sikler, G.; Valenzuela, T.; Verdu, J.; Weber, C.; Werth, G.

2001-01-01

HITRAP is a planned ion trap facility for capturing and cooling of highly charged ions produced at GSI in the heavy-ion complex of the UNILAC-SIS accelerators and the ESR storage ring. In this facility heavy highly charged ions up to uranium will be available as bare nuclei, hydrogen-like ions or few-electron systems at low temperatures. The trap for receiving and studying these ions is designed for operation at extremely high vacuum by cooling to cryogenic temperatures. The stored highly charged ions can be investigated in the trap itself or can be extracted from the trap at energies up to about 10 keV/q. The proposed physics experiments are collision studies with highly charged ions at well-defined low energies (eV/u), high-accuracy measurements to determine the g-factor of the electron bound in a hydrogen-like heavy ion and the atomic binding energies of few-electron systems, laser spectroscopy of HFS transitions and X-ray spectroscopy

METHOD AND APPARATUS FOR TRAPPING IONS IN A MAGNETIC FIELD

Science.gov (United States)

Luce, J.S.

1962-04-17

A method and apparatus are described for trapping ions within an evacuated container and within a magnetic field utilizing dissociation and/or ionization of molecular ions to form atomic ions and energetic neutral particles. The atomic ions are magnetically trapped as a result of a change of charge-to- mass ratio. The molecular ions are injected into the container and into the path of an energetic carbon arc discharge which dissociates and/or ionizes a portion of the molecular ions into atomic ions and energetic neutrals. The resulting atomic ions are trapped by the magnetic field to form a circulating beam of atomic ions, and the energetic neutrals pass out of the system and may be utilized in a particle accelerator. (AEC)

Capacitance, charge dynamics, and electrolyte-surface interactions in functionalized carbide-derived carbon electrodes

Directory of Open Access Journals (Sweden)

Boris Dyatkin

2015-12-01

Full Text Available This study analyzed the dynamics of ionic liquid electrolyte inside of defunctionalized, hydrogenated, and aminated pores of carbide-derived carbon supercapacitor electrodes. The approach tailors surface functionalities and tunes nanoporous structures to decouple the influence of pore wall composition on capacitance, ionic resistance, and long-term cyclability. Quasi-elastic neutron scattering probes the self-diffusion properties and electrode-ion interactions of electrolyte molecules confined in functionalized pores. Room-temperature ionic liquid interactions in confined pores are strongest when the hydrogen-containing groups are present on the surface. This property translates into higher capacitance and greater ion transport through pores during electrochemical cycling. Unlike hydrogenated pores, aminated pores do not favorably interact with ionic liquid ions and, subsequently, are outperformed by defunctionalized surfaces.

Capacitance, charge dynamics, and electrolyte-surface interactions in functionalized carbide-derived carbon electrodes

Energy Technology Data Exchange (ETDEWEB)

Dyatkin, Boris; Mamontov, Eugene; Cook, Kevin M.; Gogotsi, Yury

2015-12-01

This study analyzed the dynamics of ionic liquid electrolyte inside of defunctionalized, hydrogenated, and aminated pores of carbide-derived carbon supercapacitor electrodes. The approach tailors surface functionalities and tunes nanoporous structures to decouple the influence of pore wall composition on capacitance, ionic resistance, and long-term cyclability. Quasi-elastic neutron scattering probes the self-diffusion properties and electrode-ion interactions of electrolyte molecules confined in functionalized pores. Room-temperature ionic liquid interactions in confined pores are strongest when the hydrogen-containing groups are present on the surface. This property translates into higher capacitance and greater ion transport through pores during electrochemical cycling. Unlike hydrogenated pores, aminated pores do not favorably interact with ionic liquid ions and, subsequently, are outperformed by defunctionalized surfaces.

Structure formation and surface chemistry of ionic liquids on model electrode surfaces—Model studies for the electrode | electrolyte interface in Li-ion batteries

Science.gov (United States)

Buchner, Florian; Uhl, Benedikt; Forster-Tonigold, Katrin; Bansmann, Joachim; Groß, Axel; Behm, R. Jürgen

2018-05-01

Ionic liquids (ILs) are considered as attractive electrolyte solvents in modern battery concepts such as Li-ion batteries. Here we present a comprehensive review of the results of previous model studies on the interaction of the battery relevant IL 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP]+[TFSI]-) with a series of structurally and chemically well-defined model electrode surfaces, which are increasingly complex and relevant for battery applications [Ag(111), Au(111), Cu(111), pristine and lithiated highly oriented pyrolytic graphite (HOPG), and rutile TiO2(110)]. Combining surface science techniques such as high resolution scanning tunneling microscopy and X-ray photoelectron spectroscopy for characterizing surface structure and chemical composition in deposited (sub-)monolayer adlayers with dispersion corrected density functional theory based calculations, this work aims at a molecular scale understanding of the fundamental processes at the electrode | electrolyte interface, which are crucial for the development of the so-called solid electrolyte interphase (SEI) layer in batteries. Performed under idealized conditions, in an ultrahigh vacuum environment, these model studies provide detailed insights on the structure formation in the adlayer, the substrate-adsorbate and adsorbate-adsorbate interactions responsible for this, and the tendency for chemically induced decomposition of the IL. To mimic the situation in an electrolyte, we also investigated the interaction of adsorbed IL (sub-)monolayers with coadsorbed lithium. Even at 80 K, postdeposited Li is found to react with the IL, leading to decomposition products such as LiF, Li3N, Li2S, LixSOy, and Li2O. In the absence of a [BMP]+[TFSI]- adlayer, it tends to adsorb, dissolve, or intercalate into the substrate (metals, HOPG) or to react with the substrate (TiO2) above a critical temperature, forming LiOx and Ti3+ species in the latter case. Finally, the formation of stable

Trapping behaviour of deuterium ions implanted into tungsten simultaneously with carbon ions

International Nuclear Information System (INIS)

Kobayashi, Makoto; Suzuki, Sachiko; Wang, Wanjing; Kurata, Rie; Kida, Katsuya; Oya, Yasuhisa; Okuno, Kenji; Ashikawa, Naoko; Sagara, Akio; Yoshida, Naoaki

2009-01-01

The trapping behaviour of deuterium ions implanted into tungsten simultaneously with carbon ions was investigated by thermal desorption spectroscopy (TDS) and x-ray photoelectron spectroscopy (XPS). The D 2 TDS spectrum consisted of three desorption stages, namely desorption of deuterium trapped by intrinsic defects, ion-induced defects and carbon with the formation of the C-D bond. Although the deuterium retention trapped by intrinsic defects was almost constant, that by ion-induced defects increased as the ion fluence increased. The retention of deuterium with the formation of the C-D bond was saturated at an ion fluence of 0.5x10 22 D + m -2 , where the major process was changed from the sputtering of tungsten with the formation of a W-C mixture to the formation of a C-C layer, and deuterium retention as the C-D bond decreased. It was concluded that the C-C layer would enhance the chemical sputtering of carbon with deuterium with the formation of CD x and the chemical state of carbon would control the deuterium retention in tungsten under C + -D 2 + implantation.

CrossRef Space-charge effects in Penning ion traps

CERN Document Server

Porobić, T; Breitenfeldt, M; Couratin, C; Finlay, P; Knecht, A; Fabian, X; Friedag, P; Fléchard, X; Liénard, E; Ban, G; Zákoucký, D; Soti, G; Van Gorp, S; Weinheimer, Ch; Wursten, E; Severijns, N

2015-01-01

The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with View the MathML source using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations.

Electrode assembly for a lithium ion battery, process for the production of such electrode assembly, and lithium ion battery comprising such electrode assemblies

NARCIS (Netherlands)

Mulder, F.M.; Wagemaker, M.

2013-01-01

The invention provides an electrode assembly for a lithium ion battery, the electrode assembly comprising a lithium storage electrode layer on a current collector, wherein the lithium storage electrode layer is a porous layer having a porosity in the range of -35 %, with pores having pore widths in

Selective observation of charge storing ions in supercapacitor electrode materials.

Science.gov (United States)

Forse, Alexander C; Griffin, John M; Grey, Clare P

2018-02-01

Nuclear magnetic resonance (NMR) spectroscopy has emerged as a useful technique for probing the structure and dynamics of the electrode-electrolyte interface in supercapacitors, as ions inside the pores of the carbon electrodes can be studied separately from bulk electrolyte. However, in some cases spectral resolution can limit the information that can be obtained. In this study we address this issue by showing how cross polarisation (CP) NMR experiments can be used to selectively observe the in-pore ions in supercapacitor electrode materials. We do this by transferring magnetisation from 13 C nuclei in porous carbons to nearby nuclei in the cations ( 1 H) or anions ( 19 F) of an ionic liquid. Two-dimensional NMR experiments and CP kinetics measurements confirm that in-pore ions are located within Ångströms of sp 2 -hybridised carbon surfaces. Multinuclear NMR experiments hold promise for future NMR studies of supercapacitor systems where spectral resolution is limited. Copyright © 2017 University of Cambridge. Published by Elsevier Inc. All rights reserved.

Blueprint for a microwave trapped ion quantum computer.

Science.gov (United States)

Lekitsch, Bjoern; Weidt, Sebastian; Fowler, Austin G; Mølmer, Klaus; Devitt, Simon J; Wunderlich, Christof; Hensinger, Winfried K

2017-02-01

The availability of a universal quantum computer may have a fundamental impact on a vast number of research fields and on society as a whole. An increasingly large scientific and industrial community is working toward the realization of such a device. An arbitrarily large quantum computer may best be constructed using a modular approach. We present a blueprint for a trapped ion-based scalable quantum computer module, making it possible to create a scalable quantum computer architecture based on long-wavelength radiation quantum gates. The modules control all operations as stand-alone units, are constructed using silicon microfabrication techniques, and are within reach of current technology. To perform the required quantum computations, the modules make use of long-wavelength radiation-based quantum gate technology. To scale this microwave quantum computer architecture to a large size, we present a fully scalable design that makes use of ion transport between different modules, thereby allowing arbitrarily many modules to be connected to construct a large-scale device. A high error-threshold surface error correction code can be implemented in the proposed architecture to execute fault-tolerant operations. With appropriate adjustments, the proposed modules are also suitable for alternative trapped ion quantum computer architectures, such as schemes using photonic interconnects.

Chemical characterization of individual microparticles using an ion trap: real-time chemical analysis of aerosol particles

International Nuclear Information System (INIS)

Yang, Mo; Whitten, W.B.; Reilly, P.T.A.; Gieray, R.; Ramsey, J.M.

1996-01-01

This paper describes initial experiments to perform laser ablation mass spectrometry in real time on airborne microparticles. The microparticles are sampled directly from the air by a particle inlet system into the vacuum chamber of a mass spectrometer. An incoming particle is detected as it passes through two CW laser beams and a pulsed laser is triggered to intercept the particle for laser ablation/ionization in the mass spectrometer. The initial studies were made with an existing ion trap mass spectrometer with the particle sampling occurring at the center of the trap electrodes. Performance of the inlet system, particle detection, and preliminary results are described

Atomic and nuclear physics with stored particles in ion traps

CERN Document Server

Kluge, H J; Herfurth, F; Quint, W

2002-01-01

Trapping and cooling techniques play an increasingly important role in many areas of science. This review concentrates on recent applications of ion traps installed at accelerator facilities to atomic and nuclear physics such as mass spectrometry of radioactive isotopes, weak interaction studies, symmetry tests, determination of fundamental constants, laser spectroscopy, and spectroscopy of highly-charged ions. In addition, ion traps are proven to be extremely efficient devices for (radioactive) ion beam manipulation as, for example, retardation, accumulation, cooling, beam cleaning, charge-breeding, and bunching.

Parallel Transport Quantum Logic Gates with Trapped Ions.

Science.gov (United States)

de Clercq, Ludwig E; Lo, Hsiang-Yu; Marinelli, Matteo; Nadlinger, David; Oswald, Robin; Negnevitsky, Vlad; Kienzler, Daniel; Keitch, Ben; Home, Jonathan P

2016-02-26

We demonstrate single-qubit operations by transporting a beryllium ion with a controlled velocity through a stationary laser beam. We use these to perform coherent sequences of quantum operations, and to perform parallel quantum logic gates on two ions in different processing zones of a multiplexed ion trap chip using a single recycled laser beam. For the latter, we demonstrate individually addressed single-qubit gates by local control of the speed of each ion. The fidelities we observe are consistent with operations performed using standard methods involving static ions and pulsed laser fields. This work therefore provides a path to scalable ion trap quantum computing with reduced requirements on the optical control complexity.

The streaming-trapped ion interface in the equatorial inner magnetosphere

Science.gov (United States)

Lin, J.; Horwitz, J. L.; Gallagher, D.; Pollock, C. J.

1994-01-01

Spacecraft measurements of core ions on L=4-7 field-lines typically show trapped ion distributions near the magnetic equator, and frequently indicate field-aligned ion streams at higher latitudes. The nature of the transition between them may indicate both the microphysics of hot-cold plasma interactions and overall consequences for core plasma evolution. We have undertaken a statistical analysis and characterization of this interface and its relation to the equatorial region of the inner magnetosphere. In this analysis, we have characterized such features as the equatorial ion flux anisotropy, the penetration of field-aligned ionospheric streams into the equatorial region, the scale of the transition into trapped ion populations, and the transition latitude. We found that most transition latitudes occur within 13 deg of the equator. The typical values of equatorial ion anisotropies are consistent with bi-Maxwellian temperature ratios of T(sub perpendicular)/T(sub parallel) in the range of 3-5. The latitudinal scales for the edges of the trapped ion populations display a rather strong peak in the 2-3 deg range. We also found that there is a trend for the penetration ratio, the anisotropy half width, and the transition scale length to decrease with a higher equatorial ion anisotropy. We may interpret these features in terms of Liouville mapping of equatorially trapped ions and the reflection of the incoming ionospheric ion streams from the equatorial potential peaks associated with such trapped ions.

Electrode cooling for long pulse high current ion sources

International Nuclear Information System (INIS)

McKenzie-Wilson, R.B.

1979-01-01

The need for cooling of electrode surface in ion sources for neutral beam line applications is summarized. The properties of possible cooling fluids are discussed and the decision to use water as a cooling fluid of choice is explained. The influence of source geometry on the design of a cooling canal is examined and two possible designs are presented. The need for model testing and the results of the tests on a model cathode are also discussed. Some remarks are also made on a method of predicting burnout failure of a cooled electrode

Thermoluminescence study of the trapped charge at an alumina surface electrode in different dielectric barrier discharge regimes

Energy Technology Data Exchange (ETDEWEB)

Ambrico, P F; Ambrico, M; Dilecce, G; De Benedictis, S [Consiglio Nazionale delle Ricerche, Istituto di Metodologie Inorganiche e dei Plasmi UOS Bari-c/o Dipartimento di Chimica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy); Colaianni, A [Dipartimento di Geologia e Geofisica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy); Schiavulli, L, E-mail: paolofrancesco.ambrico@cnr.i [Dipartimento Interateneo di Fisica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy)

2010-08-18

In this study, the charge trapping effect in alumina dielectric surfaces has been deeply investigated by means of a dedicated dielectric barrier discharge apparatus in different discharge regimes and gas mixtures. This work further validates our previous findings in the case of air discharges in a filamentary regime. Long lasting charge trapping has been evidenced by ex situ thermoluminescence characterizations of alumina dielectric barrier plates exposed to a plasma. The density of trapped surface charges was found to be higher in the glow discharge with respect to pseudo-glow and filamentary regimes, and for all regimes the minimum trap activation temperature was 390 K and the trap energy was less than or around 1 eV. This implies that in the case of glow discharges a higher reservoir of electrons is present. Also, the effect was found to persist for several days after running the discharge.

Thermoluminescence study of the trapped charge at an alumina surface electrode in different dielectric barrier discharge regimes

International Nuclear Information System (INIS)

Ambrico, P F; Ambrico, M; Dilecce, G; De Benedictis, S; Colaianni, A; Schiavulli, L

2010-01-01

In this study, the charge trapping effect in alumina dielectric surfaces has been deeply investigated by means of a dedicated dielectric barrier discharge apparatus in different discharge regimes and gas mixtures. This work further validates our previous findings in the case of air discharges in a filamentary regime. Long lasting charge trapping has been evidenced by ex situ thermoluminescence characterizations of alumina dielectric barrier plates exposed to a plasma. The density of trapped surface charges was found to be higher in the glow discharge with respect to pseudo-glow and filamentary regimes, and for all regimes the minimum trap activation temperature was 390 K and the trap energy was less than or around 1 eV. This implies that in the case of glow discharges a higher reservoir of electrons is present. Also, the effect was found to persist for several days after running the discharge.

Measurement of few-electron uranium ions on a high-energy electron beam ion trap

International Nuclear Information System (INIS)

Beiersdorfer, P.

1994-01-01

The high-energy electron beam ion trap, dubbed Super-EBIT, was used to produce, trap, and excite uranium ions as highly charged as fully stripped U 92+ . The production of such highly charged ions was indicated by the x-ray emission observed with high-purity Ge detectors. Moreover, high-resolution Bragg crystal spectromters were used to analyze the x-ray emission, including a detailed measurement of both the 2s 1/2 -2p 3/2 electric dipole and 2p 1/2 -2p 3/2 magnetic dipole transitions. Unlike in ion accelerators, where the uranium ions move at relativistic speeds, the ions in this trap are stationary. Thus very precise measurements of the transition energies could be made, and the QED contribution to the transition energies could be measured within less than 1 %. Details of the production of these highly charged ions and their measurement is given

Loading of mass spectrometry ion trap with Th ions by laser ablation for nuclear frequency standard application.

Science.gov (United States)

Borisyuk, Petr V; Derevyashkin, Sergey P; Khabarova, Ksenia Y; Kolachevsky, Nikolay N; Lebedinsky, Yury Y; Poteshin, Sergey S; Sysoev, Alexey A; Tkalya, Evgeny V; Tregubov, Dmitry O; Troyan, Viktor I; Vasiliev, Oleg S; Yakovlev, Valery P; Yudin, Valery I

2017-08-01

We describe an original multisectional quadrupole ion trap aimed to realize nuclear frequency standard based on the unique isomer transition in thorium nucleus. It is shown that the system effectively operates on Th + , Th 2+ and Th 3+ ions produced by laser ablation of metallic thorium-232 target. Laser intensity used for ablation is about 6 GW/cm 2 . Via applying a bias potential to every control voltage including the RF one, we are able not only to manipulate ions within the energy range as wide as 1-500 eV but to specially adjust trap potentials in order to work mainly with ions that belong to energy distribution maximum and therefore to effectively enhance the number of trapped ions. Measurement of energy distributions of 232 Th + , 232 Th 2+ , 232 Th 3+ ions obtained by laser ablation allows us to define optimal potential values for trapping process. Observed number of ions inside trap in dependence on trapping time is found to obey an unusually slow - logarithmic decay law that needs more careful study.

Geometric Phases for Mixed States in Trapped Ions

International Nuclear Information System (INIS)

Lu Hongxia

2006-01-01

The generalization of geometric phase from the pure states to the mixed states may have potential applications in constructing geometric quantum gates. We here investigate the mixed state geometric phases and visibilities of the trapped ion system in both non-degenerate and degenerate cases. In the proposed quantum system, the geometric phases are determined by the evolution time, the initial states of trapped ions, and the initial states of photons. Moreover, special periods are gained under which the geometric phases do not change with the initial states changing of photon parts in both non-degenerate and degenerate cases. The high detection efficiency in the ion trap system implies that the mixed state geometric phases proposed here can be easily tested.

Single Ion Trapping for the Enriched Xenon Observatory

Energy Technology Data Exchange (ETDEWEB)

Waldman, Samuel J.; /Stanford U., Phys. Dept. /SLAC

2006-03-28

In the last decade, a variety of neutrino oscillation experiments have established that there is a mass difference between neutrino flavors, without determining the absolute neutrino mass scale. The Enriched Xenon Observatory for neutrinoless double beta decay (EXO) will search for the rare decays of xenon to determine the absolute value of the neutrino mass. The experiment uses a novel technique to minimize backgrounds, identifying the decay daughter product in real time using single ion spectroscopy. Here, we describe single ion trapping and spectroscopy compatible with the EXO detector. We extend the technique of single ion trapping in ultrahigh vacuum to trapping in xenon gas. With this technique, EXO will achieve a neutrino mass sensitivity of {approx_equal} .010 eV.

Electrostatic ion trap and Fourier transform measurements for high-resolution mass spectrometry

International Nuclear Information System (INIS)

Bhushan, K. G.; Gadkari, S. C.; Yakhmi, J. V.; Sahni, V. C.

2007-01-01

We report on the development of an electrostatic ion trap for high-resolution mass spectrometry. The trap works on purely electrostatic fields and hence trapping and storing of ions is not mass restrictive, unlike other techniques based on Penning, Paul, or radio frequency quadrupole ion traps. It allows simultaneous trapping and studying of multiple mass species over a large mass range. Mass spectra were recorded in ''dispersive'' and ''self-bunching'' modes of ions. Storage lifetimes of about 100 ms and mass resolving power of about 20 000 could be achieved from the fifth harmonic Fourier transform spectrum of Xe ions recorded in the self-bunching mode

Experimental characterization of the Hitrap Cooler trap with highly charged ions.

OpenAIRE

Fedotova, Svetlana

2013-01-01

The HITRAP (Highly charged Ions TRAP)facility is being set up and commissioned at GSI, Darmstadt. It will provide heavy, highly charged ions at low velocities to high-precision atomic physics experiments. Within this work the Cooler trap- the key element of the HITRAP facility was tested. The Cooler trap was assembled, aligned, and commissioned in trapping experiments with ions from off-line sources.The work performed within the scope of this thesis provided the baseline for further operation...

From transistor to trapped-ion computers for quantum chemistry.

Science.gov (United States)

Yung, M-H; Casanova, J; Mezzacapo, A; McClean, J; Lamata, L; Aspuru-Guzik, A; Solano, E

2014-01-07

Over the last few decades, quantum chemistry has progressed through the development of computational methods based on modern digital computers. However, these methods can hardly fulfill the exponentially-growing resource requirements when applied to large quantum systems. As pointed out by Feynman, this restriction is intrinsic to all computational models based on classical physics. Recently, the rapid advancement of trapped-ion technologies has opened new possibilities for quantum control and quantum simulations. Here, we present an efficient toolkit that exploits both the internal and motional degrees of freedom of trapped ions for solving problems in quantum chemistry, including molecular electronic structure, molecular dynamics, and vibronic coupling. We focus on applications that go beyond the capacity of classical computers, but may be realizable on state-of-the-art trapped-ion systems. These results allow us to envision a new paradigm of quantum chemistry that shifts from the current transistor to a near-future trapped-ion-based technology.

Electron capture by highly charged ions from surfaces and gases

International Nuclear Information System (INIS)

Allen, F.

2008-01-01

In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar 17+ and Ar 18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu -1 , charge-selected and then decelerated down to 5 eVu -1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar 17+ and Ar 18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu -1 , charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar 16+ and Xe 44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

Negative ion surface plasma source development for plasma trap injectors in Novosibirsk

International Nuclear Information System (INIS)

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

1989-01-01

Work on high-current ion sources carried out at the Novosibirsk Institute of Nuclear Physics (INP) is presented. The INP investigations on ''pure plasma'' planotron and ''pure surface'' secondary emission systems of H - generation, which preceded the surface-plasma concept developed in Novosibirsk, are described. The physical basis of the surface-plasma method of negative-ion production is considered. The versions and operating characteristics of different surface-plasma sources including the multi-ampere (approx-gt 10A) source are discussed. Research on efficient large-area (∼10 2 cm 2 ) negative ion surface-plasma emitters is described. The INP long-pulse multiaperture surface- plasma generators, with a current of about 1A, are described. 38 refs., 17 figs

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

International Nuclear Information System (INIS)

Beiersdorfer, P.

1994-01-01

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

Non-thermalization in trapped atomic ion spin chains

Science.gov (United States)

Hess, P. W.; Becker, P.; Kaplan, H. B.; Kyprianidis, A.; Lee, A. C.; Neyenhuis, B.; Pagano, G.; Richerme, P.; Senko, C.; Smith, J.; Tan, W. L.; Zhang, J.; Monroe, C.

2017-10-01

Linear arrays of trapped and laser-cooled atomic ions are a versatile platform for studying strongly interacting many-body quantum systems. Effective spins are encoded in long-lived electronic levels of each ion and made to interact through laser-mediated optical dipole forces. The advantages of experiments with cold trapped ions, including high spatio-temporal resolution, decoupling from the external environment and control over the system Hamiltonian, are used to measure quantum effects not always accessible in natural condensed matter samples. In this review, we highlight recent work using trapped ions to explore a variety of non-ergodic phenomena in long-range interacting spin models, effects that are heralded by the memory of out-of-equilibrium initial conditions. We observe long-lived memory in static magnetizations for quenched many-body localization and prethermalization, while memory is preserved in the periodic oscillations of a driven discrete time crystal state. This article is part of the themed issue 'Breakdown of ergodicity in quantum systems: from solids to synthetic matter'.

Atomic physics measurements in an electron Beam Ion Trap

International Nuclear Information System (INIS)

Marrs, R.E.; Beiersdorfer, P.; Bennett, C.

1989-01-01

An electron Beam Ion Trap at Lawrence Livermore National Laboratory is being used to produce and trap very-highly-charged ions (q ≤ 70/+/) for x-ray spectroscopy measurements. Recent measurements of transition energies and electron excitation cross sections for x-ray line emission are summarized. 13 refs., 10 figs

Determination of zirconium by fluoride ion selective electrode

International Nuclear Information System (INIS)

Mahanty, B.N.; Sonar, V.R.; Gaikwad, R.; Raul, S.; Das, D.K.; Prakash, A.; Afzal, Md.; Panakkal, J.P.

2010-01-01

Full text: Zirconium is used in a wide range of applications including nuclear clad, catalytic converters, surgical appliances, metallurgical furnaces, superconductors, ceramics, lamp filaments, anti corrosive alloys and photographical purposes. Irradiation testing of U-Zr and U-Pu-Zr fuel pins has also demonstrated their feasibility as fuel in liquid metal reactors. Different methods that are employed for the determination of zirconium are spectrophotometry, potentiometry, neutron activation analysis and mass spectrometry. Ion-selective electrode (ISE), selective to zirconium ion has been studied for the direct potentiometric measurements of zirconium ions in various samples. In the present work, an indirect method has been employed for the determination of zirconium in zirconium nitrate sample using fluoride ion selective electrode. This method is based on the addition of known excess amount of fluoride ion to react with the zirconium ion to produce zirconium tetra fluoride at about pH 2-3, followed by determination of residual fluoride ion selective electrode. The residual fluoride ion concentrations were determined from the electrode potential data using calibration plot. Subsequently, zirconium ion concentrations were determined from the concentration of consumed fluoride ions. A precision of about 2% (RSD) with the mean recovery of more than 94% has been achieved for the determination of zirconium at the concentration of 4.40 X 10 -3 moles lit -1

Energy storage and dispersion of surface acoustic waves trapped in a periodic array of mechanical resonators

DEFF Research Database (Denmark)

Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

2009-01-01

It has been shown previously that surface acoustic waves can be efficiently trapped and slowed by steep ridges on a piezoelectric substrate, giving rise to two families of shear-horizontal and vertically polarized surface waves. The mechanisms of energy storage and dispersion are explored by using...... the finite element method to model surface acoustic waves generated by high aspect ratio electrodes. A periodic model is proposed including a perfectly matched layer to simulate radiation conditions away from the sources, from which the modal distributions are found. The ratio of the mechanical energy...... confined to the electrode as compared to the total mechanical energy is calculated and is found to be increasing for increasing aspect ratio and to tend to a definite limit for the two families of surface waves. This observation is in support of the interpretation that high aspect ratio electrodes act...

Scalable quantum search using trapped ions

International Nuclear Information System (INIS)

Ivanov, S. S.; Ivanov, P. A.; Linington, I. E.; Vitanov, N. V.

2010-01-01

We propose a scalable implementation of Grover's quantum search algorithm in a trapped-ion quantum information processor. The system is initialized in an entangled Dicke state by using adiabatic techniques. The inversion-about-average and oracle operators take the form of single off-resonant laser pulses. This is made possible by utilizing the physical symmetries of the trapped-ion linear crystal. The physical realization of the algorithm represents a dramatic simplification: each logical iteration (oracle and inversion about average) requires only two physical interaction steps, in contrast to the large number of concatenated gates required by previous approaches. This not only facilitates the implementation but also increases the overall fidelity of the algorithm.

Monitoring of fluoride and iodide levels in drinking water using ion selective electrodes

International Nuclear Information System (INIS)

Ahmed, R.; Viqar-Un-Nisa; Hussain, M.; Tanwir, R.; Qureshi, S.A.

2004-01-01

Fluoride and iodide, the most important constituents of drinking water are essential as well as toxic depending on their levels. For their analysis in water mostly ion-selective electrodes, spectrophotometry, titrimetry and coulometry etc; have been used and literature has been briefly reviewed. Ion-selective electrodes offer an efficient method for the measurement of the two halides and were mostly used during this work. Fabrication of these electrodes is briefly described. Comparison of results obtained by ion selective electrode and coulometry is given. Recoveries of the added fluoride ions from the samples were good. A large number of water samples from Rawalpindi-Islamabad area were analyzed for fluoride and iodide. Levels of fluoride and iodide from two main water reservoirs of Rawalpindi and Islamabad are reported before and after treatment. Both surface and ground water samples were analyzed and results are compared and discussed. Some samples from northern areas were also analyzed for iodide and fluoride and compared. Intake of fluoride and iodide from water of different areas is also compared. Water samples, which caused bone deformation in certain areas in Punjab due to excess fluoride, were also analyzed for fluoride and results are presented. (author)

Feasibility of Cathode Surface Coating Technology for High-Energy Lithium-ion and Beyond-Lithium-ion Batteries.

Science.gov (United States)

Kalluri, Sujith; Yoon, Moonsu; Jo, Minki; Liu, Hua Kun; Dou, Shi Xue; Cho, Jaephil; Guo, Zaiping

2017-12-01

Cathode material degradation during cycling is one of the key obstacles to upgrading lithium-ion and beyond-lithium-ion batteries for high-energy and varied-temperature applications. Herein, we highlight recent progress in material surface-coating as the foremost solution to resist the surface phase-transitions and cracking in cathode particles in mono-valent (Li, Na, K) and multi-valent (Mg, Ca, Al) ion batteries under high-voltage and varied-temperature conditions. Importantly, we shed light on the future of materials surface-coating technology with possible research directions. In this regard, we provide our viewpoint on a novel hybrid surface-coating strategy, which has been successfully evaluated in LiCoO 2 -based-Li-ion cells under adverse conditions with industrial specifications for customer-demanding applications. The proposed coating strategy includes a first surface-coating of the as-prepared cathode powders (by sol-gel) and then an ultra-thin ceramic-oxide coating on their electrodes (by atomic-layer deposition). What makes it appealing for industry applications is that such a coating strategy can effectively maintain the integrity of materials under electro-mechanical stress, at the cathode particle and electrode- levels. Furthermore, it leads to improved energy-density and voltage retention at 4.55 V and 45 °C with highly loaded electrodes (≈24 mg.cm -2 ). Finally, the development of this coating technology for beyond-lithium-ion batteries could be a major research challenge, but one that is viable. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cold highly charged ions in a cryogenic Paul trap

Energy Technology Data Exchange (ETDEWEB)

Versolato, O. O., E-mail: oscar.versolato@mpi-hd.mpg.de; Schwarz, M.; Windberger, A.; Ullrich, J. [Max-Planck-Institut fuer Kernphysik (Germany); Schmidt, P. O. [Physikalisch-Technische Bundesanstalt (Germany); Drewsen, M. [University of Aarhus, Department of Physics and Astronomy (Denmark); Crespo Lopez-Urrutia, J. R. [Max-Planck-Institut fuer Kernphysik (Germany)

2013-03-15

Narrow optical transitions in highly charged ions (HCIs) are of particular interest for metrology and fundamental physics, exploiting the high sensitivity of HCIs to new physics. The highest sensitivity for a changing fine structure constant ever predicted for a stable atomic system is found in Ir{sup 17 + }. However, laser spectroscopy of HCIs is hindered by the large ({approx} 10{sup 6} K) temperatures at which they are produced and trapped. An unprecedented improvement in such laser spectroscopy can be obtained when HCIs are cooled down to the mK range in a linear Paul trap. We have developed a cryogenic linear Paul trap in which HCIs will be sympathetically cooled by {sup 9}Be{sup + } ions. Optimized optical access for laser light is provided while maintaining excellent UHV conditions. The Paul trap will be connected to an electron beam ion trap (EBIT) which is able to produce a wide range of HCIs. This EBIT will also provide the first experimental input needed for the determination of the transition energies in Ir{sup 17 + }, enabling further laser-spectroscopic investigations of this promising HCI.

Polyanion-Type Electrode Materials for Sodium-Ion Batteries.

Science.gov (United States)

Ni, Qiao; Bai, Ying; Wu, Feng; Wu, Chuan

2017-03-01

Sodium-ion batteries, representative members of the post-lithium-battery club, are very attractive and promising for large-scale energy storage applications. The increasing technological improvements in sodium-ion batteries (Na-ion batteries) are being driven by the demand for Na-based electrode materials that are resource-abundant, cost-effective, and long lasting. Polyanion-type compounds are among the most promising electrode materials for Na-ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion-type electrode materials are Na 3 V 2 (PO 4 ) 3 and NaTi 2 (PO 4 ) 3 for Na-based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na-ion batteries. Carbonophosphate Na 3 MnCO 3 PO 4 and amorphous FePO 4 have also recently emerged and are contributing to further developing the research scope of polyanion-type Na-ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion-type electrode materials for Na-ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems.

Polyanion‐Type Electrode Materials for Sodium‐Ion Batteries

Science.gov (United States)

Ni, Qiao; Wu, Feng

2017-01-01

Sodium‐ion batteries, representative members of the post‐lithium‐battery club, are very attractive and promising for large‐scale energy storage applications. The increasing technological improvements in sodium‐ion batteries (Na‐ion batteries) are being driven by the demand for Na‐based electrode materials that are resource‐abundant, cost‐effective, and long lasting. Polyanion‐type compounds are among the most promising electrode materials for Na‐ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion‐type electrode materials are Na3V2(PO4)3 and NaTi2(PO4)3 for Na‐based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na‐ion batteries. Carbonophosphate Na3MnCO3PO4 and amorphous FePO4 have also recently emerged and are contributing to further developing the research scope of polyanion‐type Na‐ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion‐type electrode materials for Na‐ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems. PMID:28331782

Deuterium trapping in carbon fiber composites under high fluence

International Nuclear Information System (INIS)

Airapetov, A.A.; Begrambekov, L.B.; Kuzmin, A.A.; Shigin, P.A.; Zakharov, A.M.

2010-01-01

The paper is devoted to investigation of deuterium trapping in CFC, dance graphite MPG-8 and pyrolytic graphite (PG) under plasma ion- and electron irradiation. Number of specific features of deuterium trapping and retention under plasma ion and electron irradiation is presented and discussed. In particular it is shown that 1) deuterium trapping takes place even when energy of impinging ions approaches zero; 2) deuterium is trapped under irradiation by plasma electrons; 3) under irradiation at equal fluences deuterium trapping is higher, when ion flux is smaller. High energy ion penetrating the surfaces are trapped in the traps created at the expense of their kinetic energy. The process may be named 'kinetic trapping'. Under low energy (smaller than 200 eV) electron and/or ion irradiation the energy of inelastic interaction on the surface provides creation of active centers, which initiate dissociation of deuterium sorbed on the surface, penetration of deuterium atoms into graphite and their trapping in specific low energy traps. The term 'potential trapping' is proposed for this type of trapping. Under high energy irradiation such atoms can fill the traps formed through kinetic mechanism. Origination of moveable deuterium atoms from the layer of surface sorption seems to be time dependent process and it is a reason of increase of trapping along with irradiation time. New features of deuterium trapping and retention in graphite evaluated in this study offer new opportunities for analysis and correct estimation of hydrogen isotope trapping and retention in tokamaks having graphite tiles. (authors)

Confinement in a cryogenic Penning trap of highest charge state ions from EBIT

International Nuclear Information System (INIS)

Schneider, D.

1994-01-01

The retrapping of highly charged Xe 44+ and Th 68+,72+ ions extracted from an open-quotes Electron Beam Ion Trapclose quotes (EBIT) is demonstrated after injection of the ions into RETRAP, a cryogenic Penning trap (up to 6 Tesla magnetic field) currently with an open cylinder design. Ion extraction in a short pulse (5-20 μsec) from EBIT, essential for efficient retrapping, is employed. The ions are slowed down upon entering a deceleration tube mounted above the trap within the magnetic field. The potential is then rapidly (100 ns) decreased, enabling low energy ions to enter the trap. Capture efficiencies up to 25% are observed via detection of the delayed ion release pulse with a detector below the trap. Signal voltages induced in a tuned circuit due to single and multiple ions have been observed by tuning the ion resonant axial oscillation frequencies for different ions. Results from transporting and retrapping of the ions, as well as their detection, are described and the trapping efficiency is discussed, The motivation for these studies is to cool the trapped very highly charged ions to low temperatures (< 4 K) in order to perform ultrahigh resolution precision spectroscopy, collision studies at ultra low energies and to observe phase transitions in Coulomb clusters of highly charged ions

Experiments with trapped ions and ultrafast laser pulses

Science.gov (United States)

Johnson, Kale Gifford

Since the dawn of quantum information science, laser-cooled trapped atomic ions have been one of the most compelling systems for the physical realization of a quantum computer. By applying qubit state dependent forces to the ions, their collective motional modes can be used as a bus to realize entangling quantum gates. Ultrafast state-dependent kicks [1] can provide a universal set of quantum logic operations, in conjunction with ultrafast single qubit rotations [2], which uses only ultrafast laser pulses. This may present a clearer route to scaling a trapped ion processor [3]. In addition to the role that spin-dependent kicks (SDKs) play in quantum computation, their utility in fundamental quantum mechanics research is also apparent. In this thesis, we present a set of experiments which demonstrate some of the principle properties of SDKs including ion motion independence (we demonstrate single ion thermometry from the ground state to near room temperature and the largest Schrodinger cat state ever created in an oscillator), high speed operations (compared with conventional atom-laser interactions), and multi-qubit entanglement operations with speed that is not fundamentally limited by the trap oscillation frequency. We also present a method to provide higher stability in the radial mode ion oscillation frequencies of a linear radiofrequency (rf) Paul trap-a crucial factor when performing operations on the rf-sensitive modes. Finally, we present the highest atomic position sensitivity measurement of an isolated atom to date of 0.5 nm Hz. (-1/2) with a minimum uncertaintyof 1.7 nm using a 0.6 numerical aperature (NA) lens system, along with a method to correct aberrations and a direct position measurement of ion micromotion (the inherent oscillations of an ion trapped in an oscillating rf field). This development could be used to directly image atom motion in the quantum regime, along with sensing forces at the yoctonewton [10. (-24) N)] scale forgravity sensing

Quantum computing with trapped ions, atoms and light

International Nuclear Information System (INIS)

Steane, Andrew M.

2001-01-01

We consider experimental issues relevant to quantum computing, and discuss the best way to achieve the essential requirements of reliable quantum memory and gate operations. Nuclear spins in trapped ions or atoms are a very promising candidate for the qubits. We estimate the parameters required to couple atoms using light via cavity QED in order to achieve quantum gates. We briefly comment on recent improvements to the Cirac-Zoller method for coupling trapped ions via their vibrational degree of freedom. Error processes result in a trade-off between quantum gate speed and failure probability. A useful quantum computer does appear to be feasible using a combination of ion trap and optical methods. The best understood method to stabilize a large computer relies on quantum error correction. The essential ideas of this are discussed, and recent estimates of the noise requirements in a quantum computing device are given

Simulating quantum effects of cosmological expansion using a static ion trap

Science.gov (United States)

Menicucci, Nicolas C.; Olson, S. Jay; Milburn, Gerard J.

2010-09-01

We propose a new experimental test bed that uses ions in the collective ground state of a static trap to study the analogue of quantum-field effects in cosmological spacetimes, including the Gibbons-Hawking effect for a single detector in de Sitter spacetime, as well as the possibility of modeling inflationary structure formation and the entanglement signature of de Sitter spacetime. To date, proposals for using trapped ions in analogue gravity experiments have simulated the effect of gravity on the field modes by directly manipulating the ions' motion. In contrast, by associating laboratory time with conformal time in the simulated universe, we can encode the full effect of curvature in the modulation of the laser used to couple the ions' vibrational motion and electronic states. This model simplifies the experimental requirements for modeling the analogue of an expanding universe using trapped ions, and it enlarges the validity of the ion-trap analogy to a wide range of interesting cases.

Experimental quantum simulations of many-body physics with trapped ions.

Science.gov (United States)

Schneider, Ch; Porras, Diego; Schaetz, Tobias

2012-02-01

Direct experimental access to some of the most intriguing quantum phenomena is not granted due to the lack of precise control of the relevant parameters in their naturally intricate environment. Their simulation on conventional computers is impossible, since quantum behaviour arising with superposition states or entanglement is not efficiently translatable into the classical language. However, one could gain deeper insight into complex quantum dynamics by experimentally simulating the quantum behaviour of interest in another quantum system, where the relevant parameters and interactions can be controlled and robust effects detected sufficiently well. Systems of trapped ions provide unique control of both the internal (electronic) and external (motional) degrees of freedom. The mutual Coulomb interaction between the ions allows for large interaction strengths at comparatively large mutual ion distances enabling individual control and readout. Systems of trapped ions therefore exhibit a prominent system in several physical disciplines, for example, quantum information processing or metrology. Here, we will give an overview of different trapping techniques of ions as well as implementations for coherent manipulation of their quantum states and discuss the related theoretical basics. We then report on the experimental and theoretical progress in simulating quantum many-body physics with trapped ions and present current approaches for scaling up to more ions and more-dimensional systems.

In-Source Laser Spectroscopy with the Laser Ion Source and Trap: First Direct Study of the Ground-State Properties of ^{217,219}Po

Directory of Open Access Journals (Sweden)

D. A. Fink

2015-02-01

Full Text Available A Laser Ion Source and Trap (LIST for a thick-target, isotope-separation on-line facility has been implemented at CERN ISOLDE for the production of pure, laser-ionized, radioactive ion beams. It offers two modes of operation, either as an ion guide, which performs similarly to the standard ISOLDE resonance ionization laser ion source (RILIS, or as a more selective ion source, where surface-ionized ions from the hot ion-source cavity are repelled by an electrode, while laser ionization is done within a radio-frequency quadrupole ion guide. The first physics application of the LIST enables the suppression of francium contamination in ion beams of neutron-rich polonium isotopes at ISOLDE by more than 1000 with a reduction in laser-ionization efficiency of only 20. Resonance ionization spectroscopy is performed directly inside the LIST device, allowing the study of the hyperfine structure and isotope shift of ^{217}Po for the first time. Nuclear decay spectroscopy of ^{219}Po is performed for the first time, revealing its half-life, α-to-β-decay branching ratio, and α-particle energy. This experiment demonstrates the applicability of the LIST at radioactive ion-beam facilities for the production and study of pure beams of exotic isotopes.

Use of cyclic voltammetry and electrochemical impedance spectroscopy for determination of active surface area of modified carbon-based electrodes

International Nuclear Information System (INIS)

Souza, Leticia Lopes de

2011-01-01

Carbon-based electrodes as well the ion exchange electrodes among others have been applied mainly in the treatment of industrial effluents and radioactive wastes. Carbon is also used in fuel cells as substrate for the electrocatalysts, having high surface area which surpasses its geometric area. The knowledge of the total active area is important for the determination of operating conditions of an electrochemical cell with respect to the currents to be applied (current density). In this study it was used two techniques to determine the electrochemical active surface area of glassy carbon, electrodes and ion exchange electrodes: cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The experiments were carried out with KNO 3 0.1 mol.L -1 solutions in a three-electrode electrochemical cell: carbon-based working electrode, platinum auxiliary electrode and Ag/AgCl reference electrode. The glassy carbon and porous carbon electrodes with geometric areas of 3.14 x 10 -2 and 2.83 X 10 -1 cm 2 , respectively, were used. The ion exchange electrode was prepared by mixing graphite, carbon, ion exchange resin and a binder, and this mixture was applied in three layers on carbon felt, using a geometric area of 1.0 cm 2 during the experiments. The capacitance (Cd) of the materials was determined by EIS using Bode diagrams. The value of 172 μF.cm -2 found for the glassy carbon is consistent with the literature data (∼ 200 μF.cm'- 2 ). By VC, varying the scan rate from 0.2 to 2.0 mV.s-1, the capacitance CdS (S = active surface area) in the region of the electric double layer (EDL) of each material was determined. By EIS, the values of C d , 3.0 x 10 -5 μF.cm'- 2 and 11 x 10 3 μF.cm-2, were found for the porous carbon and ion exchange electrodes, respectively, which allowed the determination of active surface areas as 3.73 x 106 cm 2 and 4.72 cm 2 . To sum up, the combined use of EIS and CV techniques is a valuable tool for the calculation of active surface

Electron capture by highly charged ions from surfaces and gases

Energy Technology Data Exchange (ETDEWEB)

Allen, F.

2008-01-11

In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

An inexpensive way to analyze the optics of electrostatic, surface-ionization ion-source configurations

International Nuclear Information System (INIS)

Balestrini, S.J.

1986-01-01

The optical characteristics of surface ionization sources can often be studied in detail with the aid of a home computer. Sources with two-dimensional symmetry are considered. Ions are created on the surface of a hot filament. An accelerating voltage, V, is applied to the source and filament. The ions are accelerated and focused into a beam by a series of electrodes containing narrow axial slits. The ordering of elementary stages of acceleration that the electrodes form from is the optical stack. The focusing parameters are the fractions of the source voltage applied to the electrodes. A portion of the ions leaves the source through a beam-defining, collimating slit in the final electrode. An ion trajectory at any point along the symmetry axis is described by a vector with two phase space components, which are treated as small quantities. The components at the filament are ω, the displacement from the symmetry axis, and ν, the velocity component of the ion parallel to the filament surface divided by its speed when it leaves the first stage. Elsewhere, the trajectory components are the displacement from the symmetry axis and the slope

Control of the conformations of ion Coulomb crystals in a Penning trap

Science.gov (United States)

Mavadia, Sandeep; Goodwin, Joseph F.; Stutter, Graham; Bharadia, Shailen; Crick, Daniel R.; Segal, Daniel M.; Thompson, Richard C.

2013-01-01

Laser-cooled atomic ions form ordered structures in radiofrequency ion traps and in Penning traps. Here we demonstrate in a Penning trap the creation and manipulation of a wide variety of ion Coulomb crystals formed from small numbers of ions. The configuration can be changed from a linear string, through intermediate geometries, to a planar structure. The transition from a linear string to a zigzag geometry is observed for the first time in a Penning trap. The conformations of the crystals are set by the applied trap potential and the laser parameters, and agree with simulations. These simulations indicate that the rotation frequency of a small crystal is mainly determined by the laser parameters, independent of the number of ions and the axial confinement strength. This system has potential applications for quantum simulation, quantum information processing and tests of fundamental physics models from quantum field theory to cosmology. PMID:24096901

Radiation damage and deuterium trapping in deuterium-ion-irradiated Fe–9Cr alloy

Energy Technology Data Exchange (ETDEWEB)

Iwakir, Hirotomo, E-mail: iwakiri@edu.u-ryukyu.ac.jp [Faculty and Graduate School of Education, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan); Tani, Munechika [Interdisciplinary Graduate School of Engineering Sciences, Kyusyu University, Kasuga, Fukuoka 816-8580 (Japan); Watanabe, Yoshiyuki [Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Yoshida, Naoaki [Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)

2014-01-15

Thermal desorption of deuterium (D{sub 2}) from deuterium-ion (D{sub 2}{sup +})-irradiated Fe–9Cr was correlated with the microstructural evolution of the alloy during irradiation with 8-keV D{sub 2}{sup +} ions following annealing to determine the retention and desorption behavior of the implanted deuterium and to identify effective traps for them, particularly at high temperature. After irradiation at 573 K, a new desorption stage formed between 650 and 1100 K at higher fluences, and cavities were observed using transmission electron microscopy. The total amount of trapped deuterium following irradiation with a fluence of 3.0 × 10{sup 22} ions/m{sup 2} was 6.8 × 10{sup 17} D{sub 2}/m{sup 2}, or approximately 0.007%. These results indicate that the deuterium atoms recombined to form D{sub 2} molecules at the surfaces of the cavities.

A study on prevention of an electric discharge at an extraction electrode of an electron cyclotron resonance ion source for cancer therapy.

Science.gov (United States)

Kishii, Y; Kawasaki, S; Kitagawa, A; Muramatsu, M; Uchida, T

2014-02-01

A compact ECR ion source has utilized for carbon radiotherapy. In order to increase beam intensity with higher electric field at the extraction electrode and be better ion supply stability for long periods, electric geometry and surface conditions of an extraction electrode have been studied. Focusing attention on black deposited substances on the extraction electrode, which were observed around the extraction electrode after long-term use, the relation between black deposited substances and the electrical insulation property is investigated. The black deposited substances were inspected for the thickness of deposit, surface roughness, structural arrangement examined using Raman spectroscopy, and characteristics of electric discharge in a test bench, which was set up to simulate the ECR ion source.

Numerical modelling of needle-grid electrodes for negative surface corona charging system

International Nuclear Information System (INIS)

Zhuang, Y; Chen, G; Rotaru, M

2011-01-01

Surface potential decay measurement is a simple and low cost tool to examine electrical properties of insulation materials. During the corona charging stage, a needle-grid electrodes system is often used to achieve uniform charge distribution on the surface of the sample. In this paper, a model using COMSOL Multiphysics has been developed to simulate the gas discharge. A well-known hydrodynamic drift-diffusion model was used. The model consists of a set of continuity equations accounting for the movement, generation and loss of charge carriers (electrons, positive and negative ions) coupled with Poisson's equation to take into account the effect of space and surface charges on the electric field. Four models with the grid electrode in different positions and several mesh sizes are compared with a model that only has the needle electrode. The results for impulse current and surface charge density on the sample clearly show the effect of the extra grid electrode with various positions.

Spectroscopic Analysis of Ion Concentration Profile at Electrode/Electrolyte Interface by Interferometry

Science.gov (United States)

Moore, David; Saraf, Ravi

2014-03-01

Owing to the difference in Fermi levels at an electrode/electrolyte interface, ions form an electrical double layer (EDL) with ion concentrations well over 10-fold compared to bulk. The concentration profile of the EDL intrinsically affects the electrochemical reaction rates at the electrode, which is of great significance in many applications, such as batteries and biosensors. Conventionally, using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the electrical properties of the EDL are represented as ``equivalent circuits'' consisting of the resistance to charge transfer (Rct), the double layer capacitance (Cdl) and a ``Warburg (constant phase) diffusion element'' that represents the long range diffusion of ions to the electrode. The translation to the well-understood physical structure can be lost as complicated effects are often lumped together. For example, the effect of subtle modification of the electrode surface by say, redox compounds, enzymes, or polymers is not directly measured, and must be inferred by capacitance changes. An interferometer method will be described to directly measure changes in concentration at the interface during redox process. This method in concert with CV or EIS performed concomitantly will lead to more information to model the diffuse layer for improved understanding of the kinetics of the reaction at different distances from the electrode. Applications to DNA and polymer adsorption binding will be discussed.

Spectroscopy of a Synthetic Trapped Ion Qubit

Science.gov (United States)

Hucul, David; Christensen, Justin E.; Hudson, Eric R.; Campbell, Wesley C.

2017-09-01

133Ba+ has been identified as an attractive ion for quantum information processing due to the unique combination of its spin-1 /2 nucleus and visible wavelength electronic transitions. Using a microgram source of radioactive material, we trap and laser cool the synthetic A =133 radioisotope of barium II in a radio-frequency ion trap. Using the same, single trapped atom, we measure the isotope shifts and hyperfine structure of the 62P1 /2↔62S1 /2 and 62P1 /2↔52D3 /2 electronic transitions that are needed for laser cooling, state preparation, and state detection of the clock-state hyperfine and optical qubits. We also report the 62P1 /2↔52D3 /2 electronic transition isotope shift for the rare A =130 and 132 barium nuclides, completing the spectroscopic characterization necessary for laser cooling all long-lived barium II isotopes.

Memory coherence of a sympathetically cooled trapped-ion qubit

International Nuclear Information System (INIS)

Home, J. P.; McDonnell, M. J.; Szwer, D. J.; Keitch, B. C.; Lucas, D. M.; Stacey, D. N.; Steane, A. M.

2009-01-01

We demonstrate sympathetic cooling of a 43 Ca + trapped-ion 'memory' qubit by a 40 Ca + 'coolant' ion sufficiently near the ground state of motion for fault-tolerant quantum logic, while maintaining coherence of the qubit. This is an essential ingredient in trapped-ion quantum computers. The isotope shifts are sufficient to suppress decoherence and phase shifts of the memory qubit due to the cooling light which illuminates both ions. We measure the qubit coherence during ten cycles of sideband cooling, finding a coherence loss of 3.3% per cooling cycle. The natural limit of the method is O(10 -4 ) infidelity per cooling cycle.

The kick-out mass selection technique for ions stored in an Electrostatic Ion Beam Trap

International Nuclear Information System (INIS)

Toker, Y; Altstein, N; Aviv, O; Rappaport, M L; Heber, O; Schwalm, D; Strasser, D; Zajfman, D

2009-01-01

A simple mass selection technique which allows one to clean a keV ion beam of undesirable masses while stored in an Electrostatic Ion Beam Trap (EIBT) is described. The technique is based on the time-of-flight principle and takes advantage of the long storage times and self-bunching that are possible in this type of traps (self bunching being the effect that keeps ions of the same mass bunched in spite of their finite distributions of velocities and trajectories). As the oscillation period is proportional to the square root of the ion mass, bunches containing ions of different masses will separate in space with increasing storage time and can be kicked out by a pulsed deflector mounted inside the trap. A mass selector of this type has been implemented successfully in an EIBT connected to an Even-Lavie supersonic expansion source and is routinely used in ongoing cluster experiments.

Dynamics of a single ion in a perturbed Penning trap: Octupolar perturbation

International Nuclear Information System (INIS)

Lara, Martin; Salas, J. Pablo

2004-01-01

Imperfections in the design or implementation of Penning traps may give rise to electrostatic perturbations that introduce nonlinearities in the dynamics. In this paper we investigate, from the point of view of classical mechanics, the dynamics of a single ion trapped in a Penning trap perturbed by an octupolar perturbation. Because of the axial symmetry of the problem, the system has two degrees of freedom. Hence, this model is ideal to be managed by numerical techniques like continuation of families of periodic orbits and Poincare surfaces of section. We find that, through the variation of the two parameters controlling the dynamics, several periodic orbits emanate from two fundamental periodic orbits. This process produces important changes (bifurcations) in the phase space structure leading to chaotic behavior

Designing of a Quadrupole Paul Ion Trap

Science.gov (United States)

Kiyani, Abouzar; Abdollahzadeh, M.; Sadat Kiai, S. M.; Zirak, A. R.

2011-08-01

The ion motion equation in a Paul ion trap known as Mathieu differential equation has been solved for the first time by using Runge-Kutta methods with 4th, 6th, and 8th orders. The first stability regions in az - qz plane and the corresponding qmax values were determined and compared. Also, the first stability regions of , , , ions in the Vdc - Vac plane were drown, and the threshold voltages for the ion separation was investigated.

Quasi-conical centrifugal ion trap

International Nuclear Information System (INIS)

Golikov, Yu.K.; Solov'ev, K.V.; Grigor'ev, D.V.; Flegontova, E.Yu.

1999-01-01

This paper describes a new excellent ion trap that principally differs from the classic hyperbolic one by its action. The action is based on the axisymmetric electrostatic quasi-conical field with the following potential type: F=F 0 [ln r - r 2 /2+z 2 ], where r, z are cylindrical dimensionless coordinates. The radial potential run (f=ln r-r 2 /2), in this case, is exactly presented by the approximation function f a =ar 2 +b/r 2 +c. In addition, there are some ranges of r (for example, 0.6< r<0.35), in which the concurrence accuracy value is above 0.5%. The paper presents the theory of particles dynamics in the centrifugal trap. Basic correlation for resolution ratios and sensitivity values are developed. Recommendations on the centrifugal trap design implementation, including the recording system, are given

Reliable reference electrodes for lithium-ion batteries

KAUST Repository

La Mantia, F.; Wessells, C.D.; Deshazer, H.D.; Cui, Yi

2013-01-01

Despite the high attention drawn to the lithium-ion batteries by the scientific and industrial community, most of the electrochemical characterization is carried out using poor reference electrodes or even no reference electrode. In this case

Trapped surfaces in spherical stars

International Nuclear Information System (INIS)

Bizon, P.; Malec, E.; O'Murchadha, N.

1988-01-01

We give necessary and sufficient conditions for the existence of trapped surfaces in spherically symmetric spacetimes. These conditions show that the formation of trapped surfaces depends on both the degree of concentration and the average flow of the matter. The result can be considered as a partial validation of the cosmic-censorship hypothesis

Cylindrical Penning traps with dynamic orthogonalized anharmonicity compensation for precision experiments

International Nuclear Information System (INIS)

Fei Xiang; Snow, W.M.

1999-01-01

Harmonic potentials can be produced in cylindrical ion traps by means of dynamic orthogonalized anharmonicity compensation with use of two (or multiple) sets of compensation electrodes. One special example is for traps with multiple identical electrodes which are not only easy to construct and allow access to the center region of the trap for particle loading and releasing, laser beams, and microwaves, but also flexible in forming harmonic potential wells in many locations. The nested trap configuration and the side-by-side trap configuration are readily available in this special scheme. Analytical solutions for cylindrical traps with multiple sets of compensation potentials are presented. This work will be useful for studies involving Penning trap diagnostics, atomic and molecular interactions (including the production of antihydrogen atoms), accurate mass measurements of exotic particles, and precision measurements of the spin precession frequencies of trapped particles

Cylindrical Penning traps with dynamic orthogonalized anharmonicity compensation for precision experiments

CERN Document Server

Fei Xiang

1999-01-01

Harmonic potentials can be produced in cylindrical ion traps by means of dynamic orthogonalized anharmonicity compensation with use of two (or multiple) sets of compensation electrodes. One special example is for traps with multiple identical electrodes which are not only easy to construct and allow access to the center region of the trap for particle loading and releasing, laser beams, and microwaves, but also flexible in forming harmonic potential wells in many locations. The nested trap configuration and the side-by-side trap configuration are readily available in this special scheme. Analytical solutions for cylindrical traps with multiple sets of compensation potentials are presented. This work will be useful for studies involving Penning trap diagnostics, atomic and molecular interactions (including the production of antihydrogen atoms), accurate mass measurements of exotic particles, and precision measurements of the spin precession frequencies of trapped particles.

A study of trapped ion dynamics by photon-correlation and pulse-probe techniques

International Nuclear Information System (INIS)

Rink, J.; Dholakia, K.; Zs, G.; Horvath, K.; Hernandez-Pozos, J. L.; Power, W.; Segal, D. M.; Thompson, R. C.; Walker, T.

1995-01-01

We demonstrate non-evasive methods for observing ion and ion cloud oscillation frequencies in a quadrupole ion trap. These trap resonances are measured for small clouds using a photon correlation technique. For large clouds the rotation frequency can be detected with the help of an additional pulsed probe laser. We show applications of the photon correlation method such as estimating the dynamic properties of a combined trap and detecting ion crystals

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

Trapped-Ion Quantum Logic with Global Radiation Fields.

Science.gov (United States)

Weidt, S; Randall, J; Webster, S C; Lake, K; Webb, A E; Cohen, I; Navickas, T; Lekitsch, B; Retzker, A; Hensinger, W K

2016-11-25

Trapped ions are a promising tool for building a large-scale quantum computer. However, the number of required radiation fields for the realization of quantum gates in any proposed ion-based architecture scales with the number of ions within the quantum computer, posing a major obstacle when imagining a device with millions of ions. Here, we present a fundamentally different approach for trapped-ion quantum computing where this detrimental scaling vanishes. The method is based on individually controlled voltages applied to each logic gate location to facilitate the actual gate operation analogous to a traditional transistor architecture within a classical computer processor. To demonstrate the key principle of this approach we implement a versatile quantum gate method based on long-wavelength radiation and use this method to generate a maximally entangled state of two quantum engineered clock qubits with fidelity 0.985(12). This quantum gate also constitutes a simple-to-implement tool for quantum metrology, sensing, and simulation.

Advanced Quadrupole Ion Trap Instrumentation for Low Level Vehicle Emissions Measurements

International Nuclear Information System (INIS)

McLuckey, S.A.

1997-01-01

Quadrupole ion trap mass spectrometry has been evaluated for its potential use in vehicle emissions measurements in vehicle test facilities as an analyzer for the top 15 compounds contributing to smog generation. A variety of ionization methods were explored including ion trap in situ chemical ionization, atmospheric sampling glow discharge ionization, and nitric oxide chemical ionization in a glow discharge ionization source coupled with anion trap mass spectrometer. Emphasis was placed on the determination of hydrocarbons and oxygenated hydrocarbons at parts per million to parts per billion levels. Ion trap in situ water chemical ionization and atmospheric sampling glow discharge ionization were both shown to be amendable to the analysis of arenes, alcohols, aldehydes and, to some degree, alkenes. Atmospheric sampling glow discharge also generated molecular ions of methy-t-butyl ether (MTBE). Neither of these ionization methods, however, were found to generate diagnostic ions for the alkanes. Nitric oxide chemical ionization, on the other hand, was found to yield diagnostic ions for alkanes, alkenes, arenes, alcohols, aldehydes, and MTBE. The ability to measure a variety of hydrocarbons present at roughly 15 parts per billion at measurement rates of 3 Hz was demonstrated. All of the ions with potential to serve as parent ions in a tandem mass spectrometry experiment were found to yield parent-to-product conversion efficiencies greater than 75%. The flexibility afforded to the ion trap by use of tailored wave-forms applied to the end-caps allows parallel monitoring schemes to be devised that provide many of the advantages of tandem mass spectrometry without major loss in measurement rate. A large loss in measurement rate would ordinarily result from the use of conventional tandem mass spectrometry experiments carried out in series for a large number of targeted components. These results have demonstrated that the ion trap has an excellent combination of

Tailored ion energy distributions on plasma electrodes

International Nuclear Information System (INIS)

Economou, Demetre J.

2013-01-01

As microelectronic device features continue to shrink approaching atomic dimensions, control of the ion energy distribution on the substrate during plasma etching and deposition becomes increasingly critical. The ion energy should be high enough to drive ion-assisted etching, but not too high to cause substrate damage or loss of selectivity. In many cases, a nearly monoenergetic ion energy distribution (IED) is desired to achieve highly selective etching. In this work, the author briefly reviews: (1) the fundamentals of development of the ion energy distribution in the sheath and (2) methods to control the IED on plasma electrodes. Such methods include the application of “tailored” voltage waveforms on an electrode in continuous wave plasmas, or the application of synchronous bias on a “boundary electrode” during a specified time window in the afterglow of pulsed plasmas

A linear radiofrequency ion trap for accumulation, bunching, and emittance improvement of radioactive ion beams

International Nuclear Information System (INIS)

Herfurth, F.; Dilling, J.; Kellerbauer, A.

2000-05-01

An ion beam cooler and buncher has been developed for the manipulation of radioactive ion beams. The gas-filled linear radiofrequency ion trap system is installed at the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. Its purpose is to accumulate the 60-keV continuous ISOLDE ion beam with high efficiency and to convert it into low-energy low-emittance ion pulses. The efficiency was found to exceed 10% in agreement with simulations. A more than 10-fold reduction of the ISOLDE beam emittance can be achieved. The system has been used successfully for first on-line experiments. Its principle, setup and performance will be discussed. (orig.)

Integrated System Technologies for Modular Trapped Ion Quantum Information Processing

Science.gov (United States)

Crain, Stephen G.

Although trapped ion technology is well-suited for quantum information science, scalability of the system remains one of the main challenges. One of the challenges associated with scaling the ion trap quantum computer is the ability to individually manipulate the increasing number of qubits. Using micro-mirrors fabricated with micro-electromechanical systems (MEMS) technology, laser beams are focused on individual ions in a linear chain and steer the focal point in two dimensions. Multiple single qubit gates are demonstrated on trapped 171Yb+ qubits and the gate performance is characterized using quantum state tomography. The system features negligible crosstalk to neighboring ions (technologies demonstrated in this thesis can be integrated to form a single quantum register with all of the necessary resources to perform local gates as well as high fidelity readout and provide a photon link to other systems.

Trapped Ion Quantum Computation by Adiabatic Passage

International Nuclear Information System (INIS)

Feng Xuni; Wu Chunfeng; Lai, C. H.; Oh, C. H.

2008-01-01

We propose a new universal quantum computation scheme for trapped ions in thermal motion via the technique of adiabatic passage, which incorporates the advantages of both the adiabatic passage and the model of trapped ions in thermal motion. Our scheme is immune from the decoherence due to spontaneous emission from excited states as the system in our scheme evolves along a dark state. In our scheme the vibrational degrees of freedom are not required to be cooled to their ground states because they are only virtually excited. It is shown that the fidelity of the resultant gate operation is still high even when the magnitude of the effective Rabi frequency moderately deviates from the desired value.

A highly permeable and enhanced surface area carbon-cloth electrode for vanadium redox flow batteries

Science.gov (United States)

Zhou, X. L.; Zhao, T. S.; Zeng, Y. K.; An, L.; Wei, L.

2016-10-01

In this work, a high-performance porous electrode, made of KOH-activated carbon-cloth, is developed for vanadium redox flow batteries (VRFBs). The macro-scale porous structure in the carbon cloth formed by weaving the carbon fibers in an ordered manner offers a low tortuosity (∼1.1) and a broad pore distribution from 5 μm to 100 μm, rendering the electrode a high hydraulic permeability and high effective ionic conductivity, which are beneficial for the electrolyte flow and ion transport through the porous electrode. The use of KOH activation method to create nano-scale pores on the carbon-fiber surfaces leads to a significant increase in the surface area for redox reactions from 2.39 m2 g-1 to 15.4 m2 g-1. The battery assembled with the present electrode delivers an energy efficiency of 80.1% and an electrolyte utilization of 74.6% at a current density of 400 mA cm-2, as opposed to an electrolyte utilization of 61.1% achieved by using a conventional carbon-paper electrode. Such a high performance is mainly attributed to the combination of the excellent mass/ion transport properties and the high surface area rendered by the present electrode. It is suggested that the KOH-activated carbon-cloth electrode is a promising candidate in redox flow batteries.

Unified theory of ballooning instabilities and temperature gradient driven trapped ion modes

International Nuclear Information System (INIS)

Xu, X.Q.

1990-08-01

A unified theory of temperature gradient driven trapped ion modes and ballooning instabilities is developed using kinetic theory in banana regimes. All known results, such as electrostatic and purely magnetic trapped particle modes and ideal MHD ballooning modes (or shear Alfven waves) are readily derived from our single general dispersion relation. Several new results from ion-ion collision and trapped particle modification of ballooning modes are derived and discussed and the interrelationship between those modes is established. 24 refs

Silver-coated ion exchange membrane electrode applied to electrochemical reduction of carbon dioxide

International Nuclear Information System (INIS)

Hori, Y.; Ito, H.; Okano, K.; Nagasu, K.; Sato, S.

2003-01-01

Silver-coated ion exchange membrane electrodes (solid polymer electrolyte, SPE) were prepared by electroless deposition of silver onto ion exchange membranes. The SPE electrodes were used for carbon dioxide (CO 2 ) reduction with 0.2 M K 2 SO 4 as the electrolyte with a platinum plate (Pt) for the counterelectrode. In an SPE electrode system prepared from a cation exchange membrane (CEM), the surface of the SPE was partly ruptured during CO 2 reduction, and the reaction was rapidly suppressed. SPE electrodes made of an anion exchange membrane (SPE/AEM) sustained reduction of CO 2 to CO for more than 2 h, whereas, the electrode potential shifted negatively during the electrolysis. The reaction is controlled by the diffusion of CO 2 through the metal layer of the SPE electrode at high current density. Ultrasonic radiation, applied to the preparation of SPE/AEM, was effective to improve the electrode properties, enhancing the electrolysis current of CO 2 reduction. Observation by a scanning electron microscope (SEM) showed that the electrode metal layer became more porous by the ultrasonic radiation treatment. The partial current density of CO 2 reduction by SPE/AEM amounted to 60 mA cm -2 , i.e. three times the upper limit of the conventional electrolysis by a plate electrode. Application of SPE device may contribute to an advancement of CO 2 fixation at ambient temperature and pressure

Study of surface atmospheric pressure glow discharge plasma based on ultrathin laminated electrodes in air

Science.gov (United States)

Zhao, Luxiang; Liu, Wenzheng; Li, Zhiyi; Ma, Chuanlong

2018-05-01

A method to generate large-area surface plasma in air by micro-discharge is proposed. Two ultrathin laminated electrode structures of non-insulating and insulating types were formed by using the nanoscale ITO conductive layer. The surface glow discharge in atmospheric air is realized in low discharge voltage by constructing the special electric field of two-dimensional unidirectional attenuation. In particular, the insulating electrode structure can avoid the loss of ITO electrodes so that the discharge stability can be increased, and the treated objects can be prevented from metal ion pollution caused by the electrode in the discharge. It has broad application prospects in the fields of aerodynamics and material surface treatment.

The injection of inert gas ions into solids: their trapping and escape

International Nuclear Information System (INIS)

Carter, G.; Armour, D.G.; Donnelly, S.E.; Ingram, D.C.; Webb, R.P.

1980-01-01

The first part of this contribution will review experimental studies of the trapping probabilities of ions injected into solids as a function of ion energy and indicate how the data can be modelled theoretically. It will be demonstrated that trapping is a two stage process, the first involving penetration into the solid and the second requiring atom dissolution and experimental evidence will be cited to show how the latter process may be dominant for light ions which create little radiation damage. For low ion fluences, injected atoms are generally trapped in isolation but as fluence increases gas-defect complexes are formed and it will be shown how post bombardment thermal evaluation studies can provide evidence for the growth of these complexes. Concomitant with trapping however, dissolved gas may be evolved from the solid by some form of sputtering process, sometimes by mechanisms much more efficient than congruent sputtering of the solid together with the trapped species. Measurements of the trapped atom concentration-ion fluence behaviour and of the evolution of one initially trapped species by bombardment with a second species provide information on the physical processes involved in trapped atom sputtering and upon the mechanism of gas incorporation saturation and experimental studies in this area, together with some first approximation theoretical investigations will be discussed. It will be shown that an important mechanism in dictating incorporation saturation, in addition to sputtering, is the atomic saturation of the solid by the implant. (author)

The application of phase contrast X-ray techniques for imaging Li-ion battery electrodes

Science.gov (United States)

Eastwood, D. S.; Bradley, R. S.; Tariq, F.; Cooper, S. J.; Taiwo, O. O.; Gelb, J.; Merkle, A.; Brett, D. J. L.; Brandon, N. P.; Withers, P. J.; Lee, P. D.; Shearing, P. R.

2014-04-01

In order to accelerate the commercialization of fuel cells and batteries across a range of applications, an understanding of the mechanisms by which they age and degrade at the microstructural level is required. Here, the most widely commercialized Li-ion batteries based on porous graphite based electrodes which de/intercalate Li+ ions during charge/discharge are studied by two phase contrast enhanced X-ray imaging modes, namely in-line phase contrast and Zernike phase contrast at the micro (synchrotron) and nano (laboratory X-ray microscope) level, respectively. The rate of charge cycling is directly dependent on the nature of the electrode microstructure, which are typically complex multi-scale 3D geometries with significant microstructural heterogeneities. We have been able to characterise the porosity and the tortuosity by micro-CT as well as the morphology of 5 individual graphite particles by nano-tomography finding that while their volume varied significantly their sphericity was surprisingly similar. The volume specific surface areas of the individual grains measured by nano-CT are significantly larger than the total volume specific surface area of the electrode from the micro-CT imaging, which can be attributed to the greater particle surface area visible at higher resolution.

The application of phase contrast X-ray techniques for imaging Li-ion battery electrodes

International Nuclear Information System (INIS)

Eastwood, D.S.; Bradley, R.S.; Tariq, F.; Cooper, S.J.; Taiwo, O.O.; Gelb, J.; Merkle, A.; Brett, D.J.L.; Brandon, N.P.; Withers, P.J.; Lee, P.D.; Shearing, P.R.

2014-01-01

In order to accelerate the commercialization of fuel cells and batteries across a range of applications, an understanding of the mechanisms by which they age and degrade at the microstructural level is required. Here, the most widely commercialized Li-ion batteries based on porous graphite based electrodes which de/intercalate Li + ions during charge/discharge are studied by two phase contrast enhanced X-ray imaging modes, namely in-line phase contrast and Zernike phase contrast at the micro (synchrotron) and nano (laboratory X-ray microscope) level, respectively. The rate of charge cycling is directly dependent on the nature of the electrode microstructure, which are typically complex multi-scale 3D geometries with significant microstructural heterogeneities. We have been able to characterise the porosity and the tortuosity by micro-CT as well as the morphology of 5 individual graphite particles by nano-tomography finding that while their volume varied significantly their sphericity was surprisingly similar. The volume specific surface areas of the individual grains measured by nano-CT are significantly larger than the total volume specific surface area of the electrode from the micro-CT imaging, which can be attributed to the greater particle surface area visible at higher resolution

Wide-angle light-trapping electrode for photovoltaic cells.

Science.gov (United States)

Omelyanovich, Mikhail M; Simovski, Constantin R

2017-10-01

In this Letter, we experimentally show that a submicron layer of a transparent conducting oxide that may serve a top electrode of a photovoltaic cell based on amorphous silicon when properly patterned by notches becomes an efficient light-trapping structure. This is so for amorphous silicon thin-film solar cells with properly chosen thicknesses of the active layers (p-i-n structure with optimal thicknesses of intrinsic and doped layers). The nanopatterned layer of transparent conducting oxide reduces both the light reflectance from the photovoltaic cell and transmittance through the photovoltaic layers for normal incidence and for all incidence angles. We explain the physical mechanism of our light-trapping effect, prove that this mechanism is realized in our structure, and show that the nanopatterning is achievable in a rather easy and affordable way that makes our method of solar cell enhancement attractive for industrial adaptations.

Deuterium trapping in tungsten

Science.gov (United States)

Poon, Michael

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV. Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

Deuterium trapping in tungsten

International Nuclear Information System (INIS)

Poon, M.

2004-01-01

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. . Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D 2 molecules inside the void with a trap energy of 1.2 eV. . Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

Deuterium trapping in tungsten

Energy Technology Data Exchange (ETDEWEB)

Poon, M

2004-07-01

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. . Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D{sub 2} molecules inside the void with a trap energy of 1.2 eV. . Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

Elucidating the Polymeric Binder Distribution within Lithium-ion Battery Electrodes Using SAICAS.

Science.gov (United States)

Kim, Kyuman; Byun, Seoungwoo; Choi, Jaecheol; Hong, Seungbum; Ryou, Myung-Hyun; Lee, Yong Min

2018-03-30

Polymeric binder distribution within electrodes is crucial to guarantee the electrochemical performance of lithium-ion batteries (LIBs) for their long-term use in applications such as electric vehicles and energy-storage systems. However, due to limited analytical tools, such analyses have not been conducted so far. Herein, the adhesion properties of LIB electrodes at different depths are measured using a surface and interfacial cutting analysis system (SAICAS). Moreover, two LiCoO 2 electrodes, dried at 130 and 230 °C, are carefully prepared and used to obtain the adhesion properties at every 10 μm of depth as well as the interface between the electrode composite and the current collector. At high drying temperatures, more of the polymeric binder material and conductive agent appears adjacent to the electrode surface, resulting in different adhesion properties as a function of depth. When the electrochemical properties are evaluated at different temperatures, the LiCoO 2 electrode dried at 130 °C shows a much better high-temperature cycling performance than does the electrode dried at 230 °C due to the uniform adhesion properties and the higher interfacial adhesion strength. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Faradaic AC Electrokinetic Flow and Particle Traps

Science.gov (United States)

Ben, Yuxing; Chang, Hsueh-Chia

2004-11-01

Faradaic reaction at higher voltages can produce co-ion polarization at AC electrodes instead of counter-ion polarization due to capacitive charging from the bulk. The Faradaic co-ion polarization also does not screen the external field and hence can produce large net electro-kinetic flows at frequencies lower than the inverse RC time of the double layer. Due to the opposite polarization of capacitve and Faradaic charging, we can reverse the direction of AC flows on electrodes by changing the voltage and frequency. Particles and bacteria are trapped and then dispersed at stagnation lines, at locations predicted by our theory, by using these two flows sequentially. This technique offers a good way to concentrate and detect bacteria.

Ion trap simulations of quantum fields in an expanding universe.

Science.gov (United States)

Alsing, Paul M; Dowling, Jonathan P; Milburn, G J

2005-06-10

We propose an experiment in which the phonon excitation of ion(s) in a trap, with a trap frequency exponentially modulated at rate kappa, exhibits a thermal spectrum with an "Unruh" temperature given by k(B)T=Planck kappa. We discuss the similarities of this experiment to the response of detectors in a de Sitter universe and the usual Unruh effect for uniformly accelerated detectors. We demonstrate a new Unruh effect for detectors that respond to antinormally ordered moments using the ion's first blue sideband transition.

Magneto optical trap recoil ion momentum spectroscopy: application to ion-atom collisions

International Nuclear Information System (INIS)

Blieck, J.

2008-10-01

87 Rb atoms have been cooled, trapped and prepared as targets for collision studies with 2 and 5 keV Na + projectiles. The physics studied deals with charge exchange processes. The active electron, which is generally the most peripheral electron of the atomic target, is transferred from the target onto the ionic projectile. The ionized target is called recoil ion. The technique used to study this physics is the MOTRIMS (Magneto Optical Trap Recoil Ion Momentum Spectroscopy) technique, which combines a magneto optical trap and a recoil ion momentum spectrometer. The spectrometer is used for the measurement of the recoil ions momentum, which gives access to all the information of the collision: the Q-value (which is the potential energy difference of the active electron on each particle) and the scattering angle of the projectile. The trap provides extremely cold targets to optimize the measurement of the momentum, and to release the latter from thermal motion. Through cinematically complete experiments, the MOTRIMS technique gives access to better resolutions on momentum measurements. Measurements of differential cross sections in initial and final capture states and in scattering angle have been done. Results obtained for differential cross sections in initial and final states show globally a good agreement with theory and an other experiment. Nevertheless, discrepancies with theory and this other experiment are shown for the measurements of doubly differential cross sections. These discrepancies are not understood yet. The particularity of the experimental setup designed and tested in this work, namely a low background noise, allows a great sensitivity to weak capture channels, and brings a technical and scientific gain compared with previous works. (author)

AC impedance electrochemical modeling of lithium-ion positive electrodes

International Nuclear Information System (INIS)

Dees, D.; Gunen, E.; Abraham, D.; Jansen, A.; Prakash, J.

2004-01-01

Under Department of Energy's Advanced Technology Development Program,various analytical diagnostic studies are being carried out to examine the lithium-ion battery technology for hybrid electric vehicle applications, and a series of electrochemical studies are being conducted to examine the performance of these batteries. An electrochemical model was developed to associate changes that were observed in the post-test analytical diagnostic studies with the electrochemical performance loss during testing of lithium ion batteries. While both electrodes in the lithium-ion cell have been studied using a similar electrochemical model, the discussion here is limited to modeling of the positive electrode. The positive electrode under study has a composite structure made of a layered nickel oxide (LiNi 0.8 Co 0.15 Al 0.05 O 2 ) active material, a carbon black and graphite additive for distributing current, and a PVDF binder all on an aluminum current collector. The electrolyte is 1.2M LiPF 6 dissolved in a mixture of EC and EMC and a Celgard micro-porous membrane is used as the separator. Planar test cells (positive/separator/negative) were constructed with a special fixture and two separator membranes that allowed the placement of a micro-reference electrode between the separator membranes (1). Electrochemical studies including AC impedance spectroscopy were then conducted on the individual electrodes to examine the performance and ageing effects in the cell. The model was developed by following the work of Professor Newman at Berkeley (2). The solid electrolyte interface (SEI) region, based on post-test analytical results, was assumed to be a film on the oxide and an oxide layer at the surface of the oxide. A double layer capacity was added in parallel with the Butler-Volmer kinetic expression. The pertinent reaction, thermodynamic, and transport equations were linearized for a small sinusoidal perturbation (3). The resulting system of differential equations was solved

Ion-selective solid-phase electrode sensitive to ammonium ions

International Nuclear Information System (INIS)

Vlasov, Yu.G.; Milonova, M.S.; Antonov, P.P.; Bychkov, E.A.; Ehfa, A.Ya.

1983-01-01

Ammonium phosphomolybdate is investigated for the purpose of using it as membrane material of ammonium-selective solid-phase electrodes. Estimation of proton mobility and ion conductivity of ammonium phosphomolybdate is performed

Spectroscopy and nonclassical fluorescence properties of single trapped Ba+ ions

International Nuclear Information System (INIS)

Bolle, J.

1998-06-01

This thesis reports on the setup and application of an experimental apparatus for spectroscopic and quantum optical investigations of a single Barium ion in a Paul trap. The realization of the apparatus, which consists of the ion trap in ultra high vacuum, two laser systems, and a photon counting detection system, is described in detail, with particular consideration of the noise sources like stray light and laser frequency instabilities. The two lasers at 493 nm and 650 nm needed to continuously excite resonance fluorescence from the Barium ion have been realized using diode lasers only. The preparation of a single localized Barium ion is described, in particular its optical cooling with the laser light and the minimization of induced vibration in the trapping potential. The purely quantum mechanical property of antibunching is observed by measuring the intensity correlation function of resonance fluorescence from the trapped and cooled ion. Interference properties of the single ion resonance fluorescence are investigated with a Mach-Zehnder interferometer. From the measured high-contrast interference signal it is proven that each individual fluorescence photon interferes with itself. The fluorescence excitation spectrum, on varying one laser frequency, is also measured and exhibits dark resonances. These measurements are compared to calculations based on optical Bloch equations for the 8 atomic levels involved. Future experiments, in particular the detection of reduced quantum fluctuations (squeezing) in one quadrature component of the resonance fluorescence, are discussed. (author)

Cluster observations of trapped ions interacting with magnetosheath mirror modes

Directory of Open Access Journals (Sweden)

J. Soucek

2011-06-01

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

Probing Surface Electric Field Noise with a Single Ion

Science.gov (United States)

2013-07-30

potentials is housed inside a Faraday cage providing more than 40 dB of attenuation for electromagnetic fields in the range of frequencies between 200...and measuring the ion quantum state [16]. Thus, by measuring the effect of electric field noise on the motional quantum state of the ion, one can probe...understand these effects . In summary, we have probed the electric field noise near an aluminum-copper surface at room temperature using a single trapped ion

Qubit Manipulations Techniques for Trapped-Ion Quantum Information Processing

Science.gov (United States)

Gaebler, John; Tan, Ting; Lin, Yiheng; Bowler, Ryan; Jost, John; Meier, Adam; Knill, Emanuel; Leibfried, Dietrich; Wineland, David; Ion Storage Team

2013-05-01

We report recent results on qubit manipulation techniques for trapped-ions towards scalable quantum information processing (QIP). We demonstrate a platform-independent benchmarking protocol for evaluating the performance of Clifford gates, which form a basis for fault-tolerant QIP. We report a demonstration of an entangling gate scheme proposed by Bermudez et al. [Phys. Rev. A. 85, 040302 (2012)] and achieve a fidelity of 0.974(4). This scheme takes advantage of dynamic decoupling which protects the qubit against dephasing errors. It can be applied directly on magnetic-field-insensitive states, and provides a number of simplifications in experimental implementation compared to some other entangling gates with trapped ions. We also report preliminary results on dissipative creation of entanglement with trapped-ions. Creation of an entangled pair does not require discrete logic gates and thus could reduce the level of quantum-coherent control needed for large-scale QIP. Supported by IARPA, ARO contract No. EAO139840, ONR, and the NIST Quantum Information Program.

Spectroscopy of highly charged tungsten ions with Electron Beam Ion Traps

International Nuclear Information System (INIS)

Sakaue, Hiroyuki A.; Kato, Daiji; Morita, Shigeru; Murakami, Izumi; Yamamoto, Norimasa; Ohashi, Hayato; Yatsurugi, Junji; Nakamura, Nobuyuki

2013-01-01

We present spectra of highly charged tungsten ions in the extreme ultra-violet (EUV) by using electron beam ion traps. The electron energy dependence of spectra is investigated of electron energies from 490 to 1440 eV. Previously unreported lines are presented in the EUV range, and some of them are identified by comparing the wavelengths with theoretical calculations. (author)

Cooling atomic ions with visible and infra-red light

Science.gov (United States)

Lindenfelser, F.; Marinelli, M.; Negnevitsky, V.; Ragg, S.; Home, J. P.

2017-06-01

We demonstrate the ability to load, cool and detect singly charged calcium ions in a surface electrode trap using only visible and infrared lasers for the trapped-ion control. As opposed to the standard methods of cooling using dipole-allowed transitions, we combine power broadening of a quadrupole transition at 729 nm with quenching of the upper level using a dipole allowed transition at 854 nm. By observing the resulting 393 nm fluorescence we are able to perform background-free detection of the ion. We show that this system can be used to smoothly transition between the Doppler cooling and sideband cooling regimes, and verify theoretical predictions throughout this range. We achieve scattering rates which reliably allow recooling after collision events and allow ions to be loaded from a thermal atomic beam. This work is compatible with recent advances in optical waveguides, and thus opens a path in current technologies for large-scale quantum information processing. In situations where dielectric materials are placed close to trapped ions, it carries the additional advantage of using wavelengths which do not lead to significant charging, which should facilitate high rate optical interfaces between remotely held ions.

Quantum computing with trapped ions

International Nuclear Information System (INIS)

Haeffner, H.; Roos, C.F.; Blatt, R.

2008-01-01

Quantum computers hold the promise of solving certain computational tasks much more efficiently than classical computers. We review recent experimental advances towards a quantum computer with trapped ions. In particular, various implementations of qubits, quantum gates and some key experiments are discussed. Furthermore, we review some implementations of quantum algorithms such as a deterministic teleportation of quantum information and an error correction scheme

New macroscopic theory of anamalous diffusion induced by the dissipative trapped-ion instability

International Nuclear Information System (INIS)

Wimmel, H.K.

1975-03-01

For an axisymmetric toroidal plasma of the TOKAMAK type a new set of dissipative trapped-fluid equations is established. In addition to E vector x B vector drifts and collisions of the trapped particles, these equations take full account of the effect of Esub(//) (of the trapped ion modes) on free and trapped particles, and of the effect of grad delta 0 (delta 0 = equilibrium fraction of trapped particles). From the new equations the linear-mode properties of the dissipative trapped-ion instability and the anomalous diffusion flux of the trapped particles are derived. (orig.) [de

Practical aspects of trapped ion mass spectrometry, 4 theory and instrumentation

CERN Document Server

March, Raymond E

2010-01-01

The expansion of the use of ion trapping in different areas of mass spectrometry and different areas of application indicates the value of a single source of information drawing together diverse inputs. This book provides an account of the theory and instrumentation of mass spectrometric applications and an introduction to ion trapping devices.

Schiff Base modified on CPE electrode and PCB gold electrode for selective determination of silver ion

Science.gov (United States)

Leepheng, Piyawan; Suramitr, Songwut; Phromyothin, Darinee

2017-09-01

The schiff base was synthesized by 2,5-thiophenedicarboxaldehyde and 1,2,4-thiadiazole-3,5-diamine with condensation method. There was modified on carbon paste electrode (CPE) and Printed circuit board (PCB) gold electrode for determination silver ion. The schiff base modified electrodes was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The electrochemical study was reported by cyclic voltammetry method and impedance spectroscopy using modified electrode as working electrode, platinum wire and Ag/AgCl as counter electrode and reference electrode, respectively. The modified electrodes have suitable detection for Ag+. The determination of silver ions using the modified electrodes depended linearly on Ag+ concentration in the range 1×10-10 M to 1×10-7 M, with cyclic voltammetry sensitivity were 2.51×108 μAM-1 and 1.88×108 μAM-1 for PCB gold electrode and CPE electrode, respectively, limits of detection were 5.33×10-9 M and 1.99×10-8 M for PCB gold electrode and CPE electrode, respectively. The modified electrodes have high accuracy, inexpensive and can applied to detection Ag+ in real samples.

High voltage and high specific capacity dual intercalating electrode Li-ion batteries

Science.gov (United States)

West, William C. (Inventor); Blanco, Mario (Inventor)

2010-01-01

The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

Nanomolar determination of Pb (II ions by selective templated electrode

Directory of Open Access Journals (Sweden)

Mazloum-Ardakani Mohammad

2012-01-01

Full Text Available Polypyrrole modified electrode, prepared by electropolymerization of pyrrole in the presence of methyl red as a dopant, was templated with respect to Pb2+ ion and applied for potentiometric and voltammetric detection of this ion. The templating process improved the analytical response characteristics of the electrode, specially their selectivity, with respect to Pb2+ ion. The improvement depends on both the incorporated ligand (dopant and the templating process, with the latter being more vital. The potentiometric response of the electrode was linear within the Pb2+ concentration range of 2.0×10-6 to 5.0×10-2 M with a near-Nernstian slope of 28.6 mV decade-1 and a detection limit of 7.0 ×10-7 M. The electrode was also used for preconcentration differential pulse anodic stripping voltammetry (DPASV and results showed that peak currents for the incorporated lead species were dependent on the metal ion concentration in the range of 1.0×10-8 to 1.0×10-3 M. The detection limit of DPASV method was 3.5 ×10-9 M. The selectivity of the electrode with respect to some transition metal ions was investigated. The modified-templated electrode was used for the successful assay of lead in two standard reference material samples.

Clearance of short circuited ion optics electrodes by capacitive discharge. [in ion thrusters

Science.gov (United States)

Poeschel, R. L.

1976-01-01

The ion optics electrodes of low specific impulse (3000 sec) mercury electron bombardment ion thrusters are vulnerable to short circuits by virtue of their relatively small interelectrode spacing (0.5 mm). Metallic flakes from backsputtered deposits are the most probable cause of such 'shorts' and 'typical' flakes have been simulated here using refractory wire that has a representative, but controllable, cross section. Shorting wires can be removed by capacitive discharge without significant damage to the electrodes. This paper describes an evaluation of 'short' removal versus electrode damage for several combinations of capacitor voltage, stored energy, and short circuit conditions.

Equilibria model for pH variations and ion adsorption in capacitive deionization electrodes.

Science.gov (United States)

Hemmatifar, Ali; Oyarzun, Diego I; Palko, James W; Hawks, Steven A; Stadermann, Michael; Santiago, Juan G

2017-10-01

Ion adsorption and equilibrium between electrolyte and microstructure of porous electrodes are at the heart of capacitive deionization (CDI) research. Surface functional groups are among the factors which fundamentally affect adsorption characteristics of the material and hence CDI system performance in general. Current CDI-based models for surface charge are mainly based on a fixed (constant) charge density, and do not treat acid-base equilibria of electrode microstructure including so-called micropores. We here expand current models by coupling the modified Donnan (mD) model with weak electrolyte acid-base equilibria theory. In our model, surface charge density can vary based on equilibrium constants (pK's) of individual surface groups as well as micropore and electrolyte pH environments. In this initial paper, we consider this equilibrium in the absence of Faradaic reactions. The model shows the preferential adsorption of cations versus anions to surfaces with respectively acidic or basic surface functional groups. We introduce a new parameter we term "chemical charge efficiency" to quantify efficiency of salt removal due to surface functional groups. We validate our model using well controlled titration experiments for an activated carbon cloth (ACC), and quantify initial and final pH of solution after adding the ACC sample. We also leverage inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography (IC) to quantify the final background concentrations of individual ionic species. Our results show a very good agreement between experiments and model. The model is extendable to a wide variety of porous electrode systems and CDI systems with applied potential. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantum computing with four-particle decoherence-free states in ion trap

OpenAIRE

Feng, Mang; Wang, Xiaoguang

2001-01-01

Quantum computing gates are proposed to apply on trapped ions in decoherence-free states. As phase changes due to time evolution of components with different eigenenergies of quantum superposition are completely frozen, quantum computing based on this model would be perfect. Possible application of our scheme in future ion-trap quantum computer is discussed.

A highly miniaturized vacuum package for a trapped ion atomic clock

Energy Technology Data Exchange (ETDEWEB)

Schwindt, Peter D. D., E-mail: pschwin@sandia.gov; Jau, Yuan-Yu; Partner, Heather; Casias, Adrian; Wagner, Adrian R.; Moorman, Matthew; Manginell, Ronald P. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Kellogg, James R.; Prestage, John D. [Jet Propulsion Laboratory, Pasadena, California 91109 (United States)

2016-05-15

We report on the development of a highly miniaturized vacuum package for use in an atomic clock utilizing trapped ytterbium-171 ions. The vacuum package is approximately 1 cm{sup 3} in size and contains a linear quadrupole RF Paul ion trap, miniature neutral Yb sources, and a non-evaporable getter pump. We describe the fabrication process for making the Yb sources and assembling the vacuum package. To prepare the vacuum package for ion trapping, it was evacuated, baked at a high temperature, and then back filled with a helium buffer gas. Once appropriate vacuum conditions were achieved in the package, it was sealed with a copper pinch-off and was subsequently pumped only by the non-evaporable getter. We demonstrated ion trapping in this vacuum package and the operation of an atomic clock, stabilizing a local oscillator to the 12.6 GHz hyperfine transition of {sup 171}Y b{sup +}. The fractional frequency stability of the clock was measured to be 2 × 10{sup −11}/τ{sup 1/2}.

Effects of electrode properties and fabricated pressure on Li ion diffusion and diffusion-induced stresses in cylindrical Li-ion batteries

International Nuclear Information System (INIS)

Zhang, Tao; Guo, Zhansheng

2014-01-01

The effects of electrode properties and fabricated pressure on Li ion diffusion and diffusion-induced stress in a cylindrical Li-ion battery are studied. It is found that hydrostatic pressure or elastic modulus variation in the active layer have little effect on the distribution of Li ions for a higher diffusivity coefficient, but both can facilitate Li ion diffusion for a lower diffusivity coefficient. The elastic modulus variation has a significant effect on the distribution of stress and hydrostatic pressure can reduce the surface stress for the lower diffusivity coefficient. A higher charging rate causes a more transient response in the stress history, but a linear charging history is observed for slow charging rates. A higher charging rate would not inflict extra damage on the electrode for the higher diffusivity coefficient and the stress history becomes highly transient and charging rate dependent for the lower diffusivity coefficient. The effect of fabricated pressure can be neglected. (paper)

Investigation into diffusion induced plastic deformation behavior in hollow lithium ion battery electrode revealed by analytical model and atomistic simulation

International Nuclear Information System (INIS)

Li, Jia; Fang, Qihong; Wu, Hong; Liu, Youwen; Wen, Pihua

2015-01-01

Highlights: • Diffusion induced stress is established. • Yield stress is dependent upon concentration. • Plastic deformation induced stress lowers tensile stress. • Plastic deformation suppresses crack nucleation. • Plastic deformation occurs not only at lithiated phase but also at electrode interior. - Abstract: This paper is theoretically suggested to describe diffusion induced stress in the elastoplastic hollow spherical silicon electrode for plastic deformation using both analytical model and molecular simulation. Based on the plastic deformation and the yield criterion, we develop this model accounting for the lithium-ion diffusion effect in hollow electrode, focusing on the concentration and stress distributions undergoing lithium-ion insertion. The results show that the two ways, applied compressive stress to inner surface or limited inner surface with higher concentration using biological membranes maintaining concentration difference, lead to the compressive stress induced by the lithium-ion diffusion effect. Hollow spherical electrode reduces effectively diffusion induced stress through controlling and tuning electrode parameters to obtain the reasonably low yield strength. According to MD simulations, plastic deformation phenomenon not only occurs at interface layer of lithiated phase, but also penetrates at electrode interior owning to confinement imposed by lithiated phase. These criteria that radial and hoop stresses reduce dramatically when plastic deformation occurs near the end faces of hollow electrode, may help guide development of new materials for lithium-ion batteries with enhanced mechanical durability, by means of reasonable designing yield strength to maintain mechanical stress below fracture strength, thereby increasing battery life.

Single trapped cold ions: a testing ground for quantum mechanics

International Nuclear Information System (INIS)

Maniscalco, S

2005-01-01

In this article I review some results obtained during my PhD work in the group of Professor Messina, at the University of Palermo. I discuss some proposals aimed at exploring fundamental issues of quantum theory, e.g. entanglement and quantum superpositions, in the context of single trapped ions. This physical context turns out to be extremely well suited both for studying fundamental features of quantum mechanics, such as the quantum-classical border, and for technological applications such as quantum logic gates and quantum registers. I focus on some procedures for engineering nonclassical states of the vibrational motion of the centre of mass of the ion. I consider both the case in which the ion interacts with classical laser beams and the case of interaction with a quantized mode of light. In particular, I discuss the generation of Schroedinger cat-like states, Bell states and Greenberger-Horn-Zeilinger states. The schemes for generating nonclassical states stem from two different quantum processes: the parity effect and the quantum state manipulation via quantum non-demolition measurement. Finally, I consider a microscopic theory of the interaction of a quantum harmonic oscillator (the centre of mass of the ion in the trapped ion context) with a bosonic thermal environment. Using an exact approach to the dynamics, I discuss a quantum theory of heating of trapped ions able to describe both the short time non-Markovian regime and the thermalization process. I conclude showing briefly how the trapped ion systems can be used as simulators of key models of open quantum systems such as the Caldeira-Leggett model. (phd tutorial)

Advanced Electrodes for High Power Li-ion Batteries

Directory of Open Access Journals (Sweden)

Christian M. Julien

2013-03-01

Full Text Available While little success has been obtained over the past few years in attempts to increase the capacity of Li-ion batteries, significant improvement in the power density has been achieved, opening the route to new applications, from hybrid electric vehicles to high-power electronics and regulation of the intermittency problem of electric energy supply on smart grids. This success has been achieved not only by decreasing the size of the active particles of the electrodes to few tens of nanometers, but also by surface modification and the synthesis of new multi-composite particles. It is the aim of this work to review the different approaches that have been successful to obtain Li-ion batteries with improved high-rate performance and to discuss how these results prefigure further improvement in the near future.

FY 1998 annual report on the development of novel, high-activity oxygen electrode by ion-implantation; 1998 nendo ion chunyuho ni yoru shinkina kokassei sanso denkyoku no kaihatsu chosa hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

An attempt has been made to develop an electrode material having high activity for oxygen generating reactions by ion-implantation, which is used to form the bulk defects (fine gaps at the atomic level) on the electrode surface, considered to serve as the active sites. It is found that implantation of the Co{sup +} or Zn{sup +} ion into a compound oxide electrode of Ti and Ru is accompanied by decreased overvoltage for oxygen generation by 50 to 100 mV. The Co{sup +} and Zn{sup +} ions, when implanted, cause damage of similar density in the thin film, decreasing its overvoltage to a similar extent, in spite of their different chemical properties, from which it is considered that the effect of ion implantation is not to change chemical properties of the film but to form a structural defect therein. A thin-film electrode of ruthenium dioxide, which is considered to be the oxygen generating electrode of the highest activity at present, is prepared and implanted with the Ru{sup +} ion, to observe the effect. The ion implantation also decreases the overvoltage by 50 to 70 mV, demonstrating its effect. The same principle is expected to be applicable to development of high-activity oxygen reducing electrode (electrode for fuel cell). (NEDO)

The application of phase contrast X-ray techniques for imaging Li-ion battery electrodes

Energy Technology Data Exchange (ETDEWEB)

Eastwood, D.S. [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Research Complex at Harwell, Didcot, Oxon OX11 0FA (United Kingdom); Bradley, R.S. [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Tariq, F.; Cooper, S.J. [Dept. Earth Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Taiwo, O.O. [Dept. Chemical Engineering, University College London, London WC1E 7JE (United Kingdom); Gelb, J.; Merkle, A. [Carl Zeiss X-ray Microscopy Inc., Pleasanton, CA 94588 (United States); Brett, D.J.L. [Dept. Chemical Engineering, University College London, London WC1E 7JE (United Kingdom); Brandon, N.P. [Dept. Earth Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Withers, P.J.; Lee, P.D. [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Research Complex at Harwell, Didcot, Oxon OX11 0FA (United Kingdom); Shearing, P.R., E-mail: p.shearing@ucl.ac.uk [Dept. Chemical Engineering, University College London, London WC1E 7JE (United Kingdom)

2014-04-01

In order to accelerate the commercialization of fuel cells and batteries across a range of applications, an understanding of the mechanisms by which they age and degrade at the microstructural level is required. Here, the most widely commercialized Li-ion batteries based on porous graphite based electrodes which de/intercalate Li{sup +} ions during charge/discharge are studied by two phase contrast enhanced X-ray imaging modes, namely in-line phase contrast and Zernike phase contrast at the micro (synchrotron) and nano (laboratory X-ray microscope) level, respectively. The rate of charge cycling is directly dependent on the nature of the electrode microstructure, which are typically complex multi-scale 3D geometries with significant microstructural heterogeneities. We have been able to characterise the porosity and the tortuosity by micro-CT as well as the morphology of 5 individual graphite particles by nano-tomography finding that while their volume varied significantly their sphericity was surprisingly similar. The volume specific surface areas of the individual grains measured by nano-CT are significantly larger than the total volume specific surface area of the electrode from the micro-CT imaging, which can be attributed to the greater particle surface area visible at higher resolution.

Phosphate Framework Electrode Materials for Sodium Ion Batteries.

Science.gov (United States)

Fang, Yongjin; Zhang, Jiexin; Xiao, Lifen; Ai, Xinping; Cao, Yuliang; Yang, Hanxi

2017-05-01

Sodium ion batteries (SIBs) have been considered as a promising alternative for the next generation of electric storage systems due to their similar electrochemistry to Li-ion batteries and the low cost of sodium resources. Exploring appropriate electrode materials with decent electrochemical performance is the key issue for development of sodium ion batteries. Due to the high structural stability, facile reaction mechanism and rich structural diversity, phosphate framework materials have attracted increasing attention as promising electrode materials for sodium ion batteries. Herein, we review the latest advances and progresses in the exploration of phosphate framework materials especially related to single-phosphates, pyrophosphates and mixed-phosphates. We provide the detailed and comprehensive understanding of structure-composition-performance relationship of materials and try to show the advantages and disadvantages of the materials for use in SIBs. In addition, some new perspectives about phosphate framework materials for SIBs are also discussed. Phosphate framework materials will be a competitive and attractive choice for use as electrodes in the next-generation of energy storage devices.

A high-energy electron beam ion trap for production of high-charge high-Z ions

International Nuclear Information System (INIS)

Knapp, D.A.; Marrs, R.E.; Elliott, S.R.; Magee, E.W.; Zasadzinski, R.

1993-01-01

We have developed a new high-energy electron beam ion trap, the first laboratory source of low-energy, few-electron, high-Z ions. We describe the device and report measurements of its performance, including the electron beam diameter, current density and energy, and measurements of the ionization balance for several high-Z elements in the trap. This device opens up a wide range of possible experiments in atomic physics, plasma physics, and nuclear physics. (orig.)

Preparation and cooling of magnesium ion crystals for sympathetic cooling of highly charged ions in a Penning trap

Energy Technology Data Exchange (ETDEWEB)

Murboeck, Tobias

2017-07-01

In this work, laser-cooled ion crystals containing 10{sup 3} to 10{sup 5} singly charged magnesium ions (Mg{sup +}) were prepared in a Penning trap. The properties of the ion crystals and their structure displaying long-range ordering were analyzed by various nondestructive techniques. After creation of the Mg{sup +} ions in the form of ion bunches in an external source, the ions were injected into the Penning trap where their temperature was reduced by eight orders of magnitude within seconds using a combination of buffer gas cooling and Doppler laser cooling. The achieved temperatures in the millikelvin-regime were close to the theoretical Doppler-cooling limit and sufficiently low to induce the transition to a crystal phase exhibiting long-range ordering. The structure of these mesoscopic ion crystals is in agreement with a model describing the crystal as a set of planar shells. This allows for a derivation of properties such as the charge density or the temperature of the observed crystals. For the process of combined buffer-gas and Doppler laser cooling an analytical model has been developed, which explains the time development of the temperature and the fluorescence signal in agreement with the experimental results. The external ion source for the production of singly charged magnesium ions was developed and characterized. A SIMION simulation of the ion creation and extraction process allows to describe the ion bunch structure and to increase the Mg{sup +} number by three orders of magnitude to 10{sup 6} Mg{sup +} ions per bunch. Other ion species with charge states between one (H{sup +}{sub 2}, C{sup +}, N{sup +}{sub 2}, CO{sup +}{sub 2}) and three (Ar{sup 3+}) were injected into the Mg{sup +} crystals. Ion crystals containing more than one ion species were observed with structures in agreement with the theory of centrifugal separation, which indicates sympathetic cooling of the non-fluorescing ion species. This preparation of mixed ion crystals is an

Relating surface chemistry and oxygen surface exchange in LnBaCo2O(5+δ) air electrodes.

Science.gov (United States)

Téllez, Helena; Druce, John; Kilner, John A; Ishihara, Tatsumi

2015-01-01

The surface and near-surface chemical composition of electroceramic materials often shows significant deviations from that of the bulk. In particular, layered materials, such as cation-ordered LnBaCo2O(5+δ) perovskites (Ln = lanthanide), undergo surface and sub-surface restructuring due to the segregation of the divalent alkaline-earth cation. These processes can take place during synthesis and processing steps (e.g. deposition, sintering or annealing), as well as at temperatures relevant for the operation of these materials as air electrodes in solid oxide fuel cells and electrolysers. Furthermore, the surface segregation in these double perovskites shows fast kinetics, starting at temperatures as low as 400 °C over short periods of time and leading to a decrease in the transition metal surface coverage exposed to the gas phase. In this work, we use a combination of stable isotope tracer labeling and surface-sensitive ion beam techniques to study the oxygen transport properties and their relationship with the surface chemistry in ordered LnBaCo2O(5+δ) perovskites. Time-of-Flight Secondary-Ion Mass Spectrometry (ToF-SIMS) combined with (18)O isotope exchange was used to determine the oxygen tracer diffusion (D*) and surface exchange (k*) coefficients. Furthermore, Low Energy Ion Scattering (LEIS) was used for the analysis of the surface and near surface chemistry as it provides information from the first mono-atomic layer of the materials. In this way, we could relate the compositional modifications (e.g. cation segregation) taking place at the electrochemically-active surface during the exchange at high temperatures and the oxygen transport properties in double perovskite electrode materials to further our understanding of the mechanism of the surface exchange process.

Sideband-cooling of trapped ytterbium-ions in the microwave regime

International Nuclear Information System (INIS)

Scharfenberger, Benedikt J.

2012-01-01

Trapped ions in a Paul trap are at present one of the most promising candidates for Quantum Information Processing (QIP). The technique that is used for this purpose in this experiment was introduced in 2001 by F. Mintert and Ch. Wunderlich. The core of this method is the use of atomic transitions in the radio- or microwave region, while a magnetic field gradient along the trap axis (where the ion chain is situated) lifts the degeneracy of the transition frequencies, such that the ions can be distinguished in frequency space; it also serves for the coupling of internal and external degrees of freedom of the ion chain. This method is called MAGIC (MAgnetic Gradient Induced Coupling). The performance of the measurements required that the apparatus of the experiment, which consists of laser sources, lambdameter, vacuum- and microwave system as well as imaging- and detection-units, had to be assembled and tested, which was an important prerequisite for the successful performance of the here described experiments. For the experiments it is advantageous to prepare the ions in an energetic state close to the motional ground state, which contributes to a reduction of the dephasing of the system while manipulating it with microwaves. By using the sideband-cooling technique to the sub-Doppler regime it is taken advantage of the fact, that ions in a linear trap are in good approximation situated in a harmonic oscillator potential and can therefore only populate discrete vibrational energy levels, whose frequency difference is given by the axial trap frequency ω z . If the system is excited by a microwave, which frequency is detuned from resonance to lower energies by a vibrational quantum, the ion looses one such phonon within each cooling-cycle. When this cycle is driven several times, the average phonon number and thus the temperature of the ion can be reduced efficiently and the ion can be initialized in a state close to the motional ground state. As sideband

A small electron beam ion trap/source facility for electron/neutral–ion collisional spectroscopy in astrophysical plasmas

Science.gov (United States)

Liang, Gui-Yun; Wei, Hui-Gang; Yuan, Da-Wei; Wang, Fei-Lu; Peng, Ji-Min; Zhong, Jia-Yong; Zhu, Xiao-Long; Schmidt, Mike; Zschornack, Günter; Ma, Xin-Wen; Zhao, Gang

2018-01-01

Spectra are fundamental observation data used for astronomical research, but understanding them strongly depends on theoretical models with many fundamental parameters from theoretical calculations. Different models give different insights for understanding a specific object. Hence, laboratory benchmarks for these theoretical models become necessary. An electron beam ion trap is an ideal facility for spectroscopic benchmarks due to its similar conditions of electron density and temperature compared to astrophysical plasmas in stellar coronae, supernova remnants and so on. In this paper, we will describe the performance of a small electron beam ion trap/source facility installed at National Astronomical Observatories, Chinese Academy of Sciences.We present some preliminary experimental results on X-ray emission, ion production, the ionization process of trapped ions as well as the effects of charge exchange on the ionization.

Stress analysis in cylindrical composition-gradient electrodes of lithium-ion battery

Science.gov (United States)

Zhong, Yaotian; Liu, Yulan; Wang, B.

2017-07-01

In recent years, the composition-gradient electrode material has been verified to be one of the most promising materials in lithium-ion battery. To investigate diffusion-induced stresses (DIS) generated in a cylindrical composition-gradient electrode, the finite deformation theory and the stress-induced diffusion hypothesis are adopted to establish the constitutive equations. Compared with stress distributions in a homogeneous electrode, the increasing forms of Young's modulus E(R) and partial molar volume Ω(R) from the electrode center to the surface along the radial direction drastically increase the maximal magnitudes of hoop and axial stresses, while both of the decreasing forms are able to make the stress fields smaller and flatter. Also, it is found that the slope of -1 for E(R) with that of -0.5 for Ω(R) is a preferable strategy to prevent the inhomogeneous electrode from cracking, while for the sake of protecting the electrode from compression failure, the optimal slope for inhomogeneous E(R) and the preferential one for Ω(R) are both -0.5. The results provide a theoretical guidance for the design of composition-gradient electrode materials.

Trapping of slow recoil ions: past results and speculations on the future

International Nuclear Information System (INIS)

Prior, M.H.

1983-01-01

A simple electrostatic ion trap has been utilized to capture low energy recoil ions made by fast heavy ion impact upon a neon gas target. The heavy ion beams have been provided by the LBL SuperHILAC and the work has so far concentrated upon studies of the decay of the trapped ion population in time following creation by the pulsed HILAC beam (3.3 msec pulse length, 36Hz repetition rate). The various charge states decay predominantly via electron capture collisions with the ambient gas in the ion trap. By varying the gas composition and density, one can determine the electron capture rate constants from which an effective (velocity averaged) capture cross-section can be obtained. The uniqueness of this work lies in the high charge states, up to Ne 10 + (fully stripped), and the low mean collision energies available (in the range 1.0 to 70.0 eV)

Investigating Surface and Interface Phenomena in LiFeBO3 Electrodes Using Photoelectron Spectroscopy Depth Profiling

DEFF Research Database (Denmark)

Maibach, Julia; Younesi, Reza; Schwarzburger, Nele

2014-01-01

The formation of surface and interface layers at the electrodes is highly important for the performance and stability of lithium ion batteries. To unravel the surface composition of electrode materials, photoelectron spectroscopy (PES) is highly suitable as it probes chemical surface and interface...... properties with high surface sensitivity. Additionally, by using synchrotron-generated hard x-rays as excitation source, larger probing depths compared to in-house PES can be achieved. Therefore, the combination of in-house soft x-ray photoelectron spectroscopy and hard x-ray photoelectron spectroscopy...

Roles of Bulk and Surface Chemistry in the Oxygen Exchange Kinetics and Related Properties of Mixed Conducting Perovskite Oxide Electrodes

Directory of Open Access Journals (Sweden)

Nicola H. Perry

2016-10-01

Full Text Available Mixed conducting perovskite oxides and related structures serving as electrodes for electrochemical oxygen incorporation and evolution in solid oxide fuel and electrolysis cells, respectively, play a significant role in determining the cell efficiency and lifetime. Desired improvements in catalytic activity for rapid surface oxygen exchange, fast bulk transport (electronic and ionic, and thermo-chemo-mechanical stability of oxygen electrodes will require increased understanding of the impact of both bulk and surface chemistry on these properties. This review highlights selected work at the International Institute for Carbon-Neutral Energy Research (I2CNER, Kyushu University, set in the context of work in the broader community, aiming to characterize and understand relationships between bulk and surface composition and oxygen electrode performance. Insights into aspects of bulk point defect chemistry, electronic structure, crystal structure, and cation choice that impact carrier concentrations and mobilities, surface exchange kinetics, and chemical expansion coefficients are emerging. At the same time, an understanding of the relationship between bulk and surface chemistry is being developed that may assist design of electrodes with more robust surface chemistries, e.g., impurity tolerance or limited surface segregation. Ion scattering techniques (e.g., secondary ion mass spectrometry, SIMS, or low energy ion scattering spectroscopy, LEIS with high surface sensitivity and increasing lateral resolution are proving useful for measuring surface exchange kinetics, diffusivity, and corresponding outer monolayer chemistry of electrodes exposed to typical operating conditions. Beyond consideration of chemical composition, the use of strain and/or a high density of active interfaces also show promise for enhancing performance.

Experimental system design for the integration of trapped-ion and superconducting qubit systems

Science.gov (United States)

De Motte, D.; Grounds, A. R.; Rehák, M.; Rodriguez Blanco, A.; Lekitsch, B.; Giri, G. S.; Neilinger, P.; Oelsner, G.; Il'ichev, E.; Grajcar, M.; Hensinger, W. K.

2016-12-01

We present a design for the experimental integration of ion trapping and superconducting qubit systems as a step towards the realization of a quantum hybrid system. The scheme addresses two key difficulties in realizing such a system: a combined microfabricated ion trap and superconducting qubit architecture, and the experimental infrastructure to facilitate both technologies. Developing upon work by Kielpinski et al. (Phys Rev Lett 108(13):130504, 2012. doi: 10.1103/PhysRevLett.108.130504), we describe the design, simulation and fabrication process for a microfabricated ion trap capable of coupling an ion to a superconducting microwave LC circuit with a coupling strength in the tens of kHz. We also describe existing difficulties in combining the experimental infrastructure of an ion trapping set-up into a dilution refrigerator with superconducting qubits and present solutions that can be immediately implemented using current technology.

Effect of covalently bonded polysiloxane multilayers on the electrochemical behavior of graphite electrode in lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Pan, Qinmin; Jiang, Yinghua [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

2008-03-15

Polysiloxane multilayers were covalently bonded to the surface of natural graphite particles via diazonium chemistry and silylation reaction. The as-prepared graphite exhibited excellent discharge-charge behavior as negative electrode materials in lithium ion batteries. The improvement in the electrochemical performance of the graphite electrodes was attributed to the formation of a stable and flexible passive film on their surfaces. It was also revealed that the chemical compositions of the multilayers exerted influence on the electrochemical behavior of the graphite electrodes. The result of this study presents a new strategy to the formation of elastic and strong passive film on the graphite electrode via molecular design. Owing to the diversity of polysilxoane multilayers, this method also enables researchers to control the surface chemistries of carbonaceous materials with flexibility. (author)

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

International Nuclear Information System (INIS)

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

2011-01-01

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

EUV spectrum of highly charged tungsten ions in electron beam ion trap

International Nuclear Information System (INIS)

Sakaue, H.A.; Kato, D.; Murakami, I.; Nakamura, N.

2016-01-01

We present spectra of highly charged tungsten ions in the extreme ultra-violet (EUV) by using electron beam ion traps. The electron energy dependence of spectra was investigated for electron energy from 540 to 1370 eV. Previously unreported lines were presented in the EUV range, and comparing the wavelengths with theoretical calculations identified them. (author)

Electron cooling of highly charged ions in penning traps; Elektronenkuehlung hochgeladener Ionen in Penningfallen

Energy Technology Data Exchange (ETDEWEB)

Moellers, B.

2007-02-08

For many high precision experiments with highly charged ions in ion traps it is necessary to work with low energy ions. One possibility to slow ions down to a very low energy in a trap is electron cooling, a method, which is already successfully used in storage rings to produce ion beams with high phase space density. Fast ions and a cold electron plasma are inserted into a Penning trap. The ions lose their energy due to Coulomb interaction with the electrons while they cross the plasma, the electrons are heated. The cooling time is the time, which is needed to cool an ion from a given initial energy to a low final energy. To calculate cooling times it is necessary to solve coupled differential equations for the ion energy and electron temperature. In a Penning trap the strong external magnetic field constitutes a theoretical challenge, as it influences the energy loss of the ions in an electron plasma, which can no longer be calculated analytically. In former estimates of cooling times this influence is neglected. But simulations show a dramatic decrease of the energy loss in the presence of a strong magnetic field, so it is necessary to investigate the effect of the magnetic field on the cooling times. This work presents a model to calculate cooling times, which includes both the magnetic field and the trap geometry. In a first step a simplified model without the external trap potential is developed. The energy loss of the ions in the magnetized electron plasma is calculated by an analytic approximation, which requires a numerical solution of integrals. With this model the dependence of the cooling time on different parameters like electron and ion density, magnetic field and the angle between ion velocity and magnetic field is studied for fully ionized uranium. In addition the influence of the electron heating is discussed. Another important topic in this context is the recombination between ions and electrons. The simplified model for cooling times allows to

Electrode Materials for Lithium/Sodium-Ion Batteries

DEFF Research Database (Denmark)

Shen, Yanbin

2014-01-01

The synthesis of electrode materials for lithium/sodium ion batteries and their structural stability during lithium/sodium insertion/extraction are the two essential issues that have limited battery application in the fields requiring long cycle life and high safety. During her PhD studies, Yanbin...... Shen systematically investigated the controlled synthesis of electrode materials for lithium/sodium ion batteries. She also investigated their formation mechanisms and structural evolution during the operation of batteries using in situ/operando X-ray diffraction techniques. The research findings...... provide insights into formation mechanisms of Li4Ti5O12 anode material from both hydrothermal and solid-state reaction. The results also contribute to a thorough understanding of the intercalation and decay mechanisms of O3/P2 layered sodium cathode materials in sodium ion batteries....

An Ideal Electrode Material, 3D Surface-Microporous Graphene for Supercapacitors with Ultrahigh Areal Capacitance

International Nuclear Information System (INIS)

Chang, Liang; Stacchiola, Dario J.; Hu, Yun Hang

2017-01-01

The efficient charge accumulation of an ideal supercapacitor electrode requires abundant micropores and its fast electrolyte-ions transport prefers meso/macropores. But, current electrode materials cannot meet both requirements, resulting in poor performance. We creatively constructed three-dimensional cabbage-coral-like graphene as an ideal electrode material, in which meso/macro channels are formed by graphene walls and rich micropores are incorporated in the surface layer of the graphene walls. The unique 3D graphene material can achieve a high gravimetric capacitance of 200 F/g with aqueous electrolyte, 3 times larger than that of commercially used activated carbon (70.8 F/g). Furthermore, it can reach an ultrahigh areal capacitance of 1.28 F/cm"2 and excellent rate capability (83.5% from 0.5 to 10 A/g) as well as high cycling stability (86.2% retention after 5000 cycles). The excellent electric double-layer performance of the 3D graphene electrode can be attributed to the fast electrolyte ion transport in the meso/macro channels and the rapid and reversible charge adsorption with negligible transport distance in the surface micropores.

Recycling positive-electrode material of a lithium-ion battery

Science.gov (United States)

Sloop, Steven E.

2017-11-21

Examples are disclosed of methods to recycle positive-electrode material of a lithium-ion battery. In one example, the positive-electrode material is heated under pressure in a concentrated lithium hydroxide solution. After heating, the positive-electrode material is separated from the concentrated lithium hydroxide solution. After separating, the positive electrode material is rinsed in a basic liquid. After rinsing, the positive-electrode material is dried and sintered.

Dielectronic recombination measurements using the Electron Beam Ion Trap

International Nuclear Information System (INIS)

Knapp, D.A.

1991-01-01

We have used the Electron Beam Ion Trap at LLNL to study dielectronic recombination in highly charged ions. Our technique is unique because we observe the x-rays from dielectronic recombination at the same time we see x-rays from all other electron-ion interactions. We have recently taken high-resolution, state-selective data that resolves individual resonances

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

Double-ion imprinted polymer @magnetic nanoparticles modified screen printed carbon electrode for simultaneous analysis of cerium and gadolinium ions

Energy Technology Data Exchange (ETDEWEB)

Prasad, Bhim Bali, E-mail: prof.bbpd@yahoo.com; Jauhari, Darshika

2015-05-22

Highlights: • Synthesis of a double-ion imprinted polymer for analysis of Ce(IV) and Gd(III). • Imprinted nano-beads were grown on MNPs-modified SPCE surface. • Voltammetric determination of both templates was carried out simultaneously. • Ultra-trace analysis with LOD (ng mL{sup −1}) 0.07 for Ce(IV) and 0.19 for Gd(III) is achieved. - Abstract: A typical, reproducible, and rugged screen printed carbon electrode, modified with dual-ion imprinted beads, was fabricated employing the “surface grafting from” approach. For this, the acyl chloride functionalized magnetic nanoparticles were first immobilized and chemically attached with a typical functional monomer (but-2-enedioic acid bis-[(2-amino-ethyl)-amide]) on the electrode surface. This was subsequently subjected to the thermal polymerization in the presence of template ions (Ce(IV) and Gd(III)), cross-linker (ethylene glycol dimethacrylate), initiator (AIBN), and multiwalled carbon nanotubes. The modified sensor was used for the simultaneous analysis of both template ions in aqueous, blood serum, and waste-water samples, using differential pulse anodic stripping voltammetry which revealed two oxidation peaks for respective templates with resolution as much as 950 mV, without any cross reactivity, interferences and false-positives. The detection limits realized by the proposed sensor, under optimized conditions, were found to be as low as 0.07 ng mL{sup −1} for Ce(IV) and 0.19 ng mL{sup −1} for Gd(III) (S/N = 3) that could eventually be helpful for lanthanide estimation at stringent levels.

Double-ion imprinted polymer @magnetic nanoparticles modified screen printed carbon electrode for simultaneous analysis of cerium and gadolinium ions

International Nuclear Information System (INIS)

Prasad, Bhim Bali; Jauhari, Darshika

2015-01-01

Highlights: • Synthesis of a double-ion imprinted polymer for analysis of Ce(IV) and Gd(III). • Imprinted nano-beads were grown on MNPs-modified SPCE surface. • Voltammetric determination of both templates was carried out simultaneously. • Ultra-trace analysis with LOD (ng mL −1 ) 0.07 for Ce(IV) and 0.19 for Gd(III) is achieved. - Abstract: A typical, reproducible, and rugged screen printed carbon electrode, modified with dual-ion imprinted beads, was fabricated employing the “surface grafting from” approach. For this, the acyl chloride functionalized magnetic nanoparticles were first immobilized and chemically attached with a typical functional monomer (but-2-enedioic acid bis-[(2-amino-ethyl)-amide]) on the electrode surface. This was subsequently subjected to the thermal polymerization in the presence of template ions (Ce(IV) and Gd(III)), cross-linker (ethylene glycol dimethacrylate), initiator (AIBN), and multiwalled carbon nanotubes. The modified sensor was used for the simultaneous analysis of both template ions in aqueous, blood serum, and waste-water samples, using differential pulse anodic stripping voltammetry which revealed two oxidation peaks for respective templates with resolution as much as 950 mV, without any cross reactivity, interferences and false-positives. The detection limits realized by the proposed sensor, under optimized conditions, were found to be as low as 0.07 ng mL −1 for Ce(IV) and 0.19 ng mL −1 for Gd(III) (S/N = 3) that could eventually be helpful for lanthanide estimation at stringent levels

Sensing local pH and ion concentration at graphene electrode surfaces using in situ Raman spectroscopy.

Science.gov (United States)

Shi, Haotian; Poudel, Nirakar; Hou, Bingya; Shen, Lang; Chen, Jihan; Benderskii, Alexander V; Cronin, Stephen B

2018-02-01

We report a novel approach to probe the local ion concentration at graphene/water interfaces using in situ Raman spectroscopy. Here, the upshifts observed in the G band Raman mode under applied electrochemical potentials are used to determine the charge density in the graphene sheet. For voltages up to ±0.8 V vs. NHE, we observe substantial upshifts in the G band Raman mode by as much as 19 cm -1 , which corresponds to electron and hole carrier densities of 1.4 × 10 13 cm -2 and Fermi energy shifts of ±430 meV. The charge density in the graphene electrode is also measured independently using the capacitance-voltage characteristics (i.e., Q = CV), and is found to be consistent with those measured by Raman spectroscopy. From charge neutrality requirements, the ion concentration in solution per unit area must be equal and opposite to the charge density in the graphene electrode. Based on these charge densities, we estimate the local ion concentration as a function of electrochemical potential in both pure DI water and 1 M KCl solutions, which span a pH range from 3.8 to 10.4 for pure DI water and net ion concentrations of ±0.7 mol L -1 for KCl under these applied voltages.

Reliable reference electrodes for lithium-ion batteries

KAUST Repository

La Mantia, F.

2013-06-01

Despite the high attention drawn to the lithium-ion batteries by the scientific and industrial community, most of the electrochemical characterization is carried out using poor reference electrodes or even no reference electrode. In this case, the performances of the active material are inaccurate, especially at high current densities. In this work we show the error committed in neglecting the polarizability of lithium counter electrodes, and we propose two reference electrodes to use in organic electrolytes based on lithium salts, namely Li4Ti5O12 and LiFePO 4. In particular, it was observed that, the polarizability of the metallic lithium counter electrode has a relevant stochastic component, which renders measurements at high current densities (above 1 mA·cm - 2) in two electrode cells non reproducible.

Integrated Visible Photonics for Trapped-Ion Quantum Computing

Science.gov (United States)

2017-06-10

etch to provide a smooth oxide facet, and clearance for fiber positioning for edge input coupling. Integrated Visible Photonics for Trapped-Ion...capability to optically address individual ions at several wavelengths. We demonstrate a dual-layered silicon nitride photonic platform for integration...coherence times, strong coulomb interactions, and optical addressability, hold great promise for implementation of practical quantum information

Mechanics of high-capacity electrodes in lithium-ion batteries

International Nuclear Information System (INIS)

Zhu, Ting

2016-01-01

Rechargeable batteries, such as lithium-ion batteries, play an important role in the emerging sustainable energy landscape. Mechanical degradation and resulting capacity fade in high-capacity electrode materials critically hinder their use in high-performance lithium-ion batteries. This paper presents an overview of recent advances in understanding the electrochemically-induced mechanical behavior of the electrode materials in lithium-ion batteries. Particular emphasis is placed on stress generation and facture in high-capacity anode materials such as silicon. Finally, we identify several important unresolved issues for future research. (topical review)

Nickel-Tin Electrode Materials for Nonaqueous Li-Ion Cells

Science.gov (United States)

Ehrlich, Grant M.; Durand, Christopher

2005-01-01

Experimental materials made from mixtures of nickel and tin powders have shown promise for use as the negative electrodes of rechargeable lithium-ion electrochemical power cells. During charging (or discharging) of a lithium-ion cell, lithium ions are absorbed into (or desorbed from, respectively) the negative electrode, typically through an intercalation or alloying process. The negative electrodes (for this purpose, designated as anodes) in state-of-the-art Li-ion cells are made of graphite, in which intercalation occurs. Alternatively, the anodes can be made from metals, in which alloying can occur. For reasons having to do with the electrochemical potential of intercalated lithium, metallic anode materials (especially materials containing tin) are regarded as safer than graphite ones; in addition, such metallic anode materials have been investigated in the hope of obtaining reversible charge/discharge capacities greater than those of graphite anodes. However, until now, each of the tin-containing metallic anode formulations tested has been found to be inadequate in some respect.

Report on the FY 1999 investigational survey on the activation of oxygen electrode by ion implantation; 1999 nendo ion chunyuho ni yoru sanso denkyoku no kasseika ni kansuru kenkyu chosa hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The oxygen electrode is important as the base electrode for water electrolysis and fuel cell, but to move it, overvoltage (activated energy) in addition to equilibrium voltage is necessary, which leads to the lowering of energy efficiency. By forming the active spot by ion implantation, the lowering of overvoltage was studied. The implantation of Ru{sup +} ion in Ruthenium dioxide thin film electrode reduced the oxygen generating overvoltage by 15-20mV. Even in the oxygen reduction, activity was also increased. The chemical composition of thin film does not change by ion implantation. The increase in activity is based on a physical change which is called the surface defect formation. The layer of ion implantation is composed of microcrystals, which is thought to contribute to the formation of any active spot. Ions were implanted in Pt electrode as a practical use material, and even in the oxygen reduction of Pt, a possibility of heightening activity by ion implantation was admitted even in the oxygen reduction of Pt. The generation of high activity oxygen by ion plantation and development of oxygen reduction electrode were established as one method as a rule. (NEDO)

Surface enhanced Raman scattering of new acridine based fluorophore adsorbed on silver electrode

Science.gov (United States)

Solovyeva, Elena V.; Myund, Liubov A.; Denisova, Anna S.

2015-10-01

4,5-Bis(N,N-di(2-hydroxyethyl)iminomethyl)acridine (BHIA) is a new acridine based fluoroionophore and a highly-selective sensor for cadmium ion. The direct interaction of the aromatic nitrogen atom with a surface is impossible since there are bulky substituents in the 4,5-positions of the acridine fragment. Nevertheless BHIA molecule shows a reliable SERS spectrum while adsorbed on a silver electrode. The analysis of SERS spectra pH dependence reveals that BHIA species adsorbed on a surface can exist in both non-protonated and protonated forms. The adsorption of BHIA from alkaline solution is accompanied by carbonaceous species formation at the surface. The intensity of such "carbon bands" turned out to be related with the supporting electrolyte (KCl) concentration. Upon lowering the electrode potential the SERS spectra of BHIA do not undergo changes but the intensity of bands decreases. This indicates that the adsorption mechanism on the silver surface is realized via aromatic system of acridine fragment. In case of such an adsorption mechanism the chelate fragment of the BHIA molecule is capable of interaction with the solution components. Addition of Cd2+ ions to a system containing BHIA adsorbed on a silver electrode in equilibrium with the solution leads to the formation of BHIA/Cd2+ complex which desorption causes the loss of SERS signal.

Slow electron acoustic double layer (SEADL) structures in bi-ion plasma with trapped electrons

Science.gov (United States)

Shan, Shaukat Ali; Imtiaz, Nadia

2018-05-01

The properties of ion acoustic double layer (IADL) structures in bi-ion plasma with electron trapping are investigated by using the quasi-potential analysis. The κ-distributed trapped electrons number density expression is truncated to some finite order of the electrostatic potential. By utilizing the reductive perturbation method, a modified Schamel equation which describes the evolution of the slow electron acoustic double layer (SEADL) with the modified speed due to the presence of bi-ion species is investigated. The Sagdeev-like potential has been derived which accounts for the effect of the electron trapping and superthermality in a bi-ion plasma. It is found that the superthermality index, the trapping efficiency of electrons, and ion to electron temperature ratio are the inhibiting parameters for the amplitude of the slow electron acoustic double layers (SEADLs). However, the enhanced population of the cold ions is found to play a supportive role for the low frequency DLs in bi-ion plasmas. The illustrations have been presented with the help of the bi-ion plasma parameters in the Earth's ionosphere F-region.

Electrocatalytic oxidation of ascorbic acid by [Fe(CN){sub 6}]{sup 3-/4-} redox couple electrostatically trapped in cationic N,N-dimethylaniline polymer film electropolymerized on diamond electrode

Energy Technology Data Exchange (ETDEWEB)

Roy, Protiva Rani [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Saha, Madhu Sudan [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Okajima, Takeyoshi [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Ohsaka, Takeo [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)]. E-mail: ohsaka@echem.titech.ac.jp

2006-06-01

Multinegatively charged metal complex, hexacyanoferrate ([Fe(CN){sub 6}]{sup 4-}), was electrostatically trapped in the cationic polymer film of N,N-dimethylaniline (PDMA) which was electrochemically deposited on the boron-doped diamond (BDD) electrode by controlled-potential electro-oxidation of the monomer. This ferrocyanide-trapped PDMA film was used to catalyze the oxidation of ascorbic acid (AA). Increase in the oxidation current response with a negative shift of the anodic peak potential was observed at the cationic PDMA film-coated BDD (PDMA|BDD) electrode, compared with that at the bare BDD electrode. A more drastic enhancement in the oxidation peak current as well as more negative shift of oxidation potential was found at the ferrocyanide-trapped PDMA film-coated BDD ([Fe(CN){sub 6}]{sup 3-/4-}|PDMA|BDD) electrode. This [Fe(CN){sub 6}]{sup 3-/4-}|PDMA|BDD electrode can be used as an amperometric sensor of AA. Ferrocyanide, electrostatically trapped in the polymer film shows more electrocatalytic activity than that coordinatively attached to the polymer film or dissolved in the solution phase. The electrocatalytic current depends on the surface coverage of ferricyanide, {gamma} {sub Fe}, within the polymer film. Diffusion coefficient (D) of AA in the solution was estimated by rotating disk electrode voltammetry: D = (5.8 {+-} 0.3) x 10{sup -6} cm{sup 2} s{sup -1}. The second-order rate constant for the catalytic oxidation of AA by ferricyanide was also estimated to be 9.0 x 10{sup 4} M{sup -1} s{sup -1}. In the hydrodynamic amperometry using the [Fe(CN){sub 6}]{sup 3-/4-}|PDMA|BDD electrode, a successive addition of 1 {mu}M AA caused the successive increase in current response with equal amplitude and the sensitivity was calculated as 0.233 {mu}A cm{sup -2} {mu}M{sup -1}.

Helium Ion Microscopy of proton exchange membrane fuel cell electrode structures

DEFF Research Database (Denmark)

Chiriaev, Serguei; Dam Madsen, Nis; Rubahn, Horst-Günter

2017-01-01

electrode interface structure dependence on ionomer content, systematically studied by Helium Ion Microscopy (HIM). A special focus was on acquiring high resolution images of the electrode structure and avoiding interface damage from irradiation and tedious sample preparation. HIM demonstrated its....... In the hot-pressed electrodes, we found more closed contact between the electrode components, reduced particle size, polymer coalescence and formation of nano-sized polymer fiber architecture between the particles. Keywords: proton exchange membrane fuel cells (PEMFCs); Helium Ion Microscopy (HIM...

Colloquium: Quantum Networks with Trapped Ions

Science.gov (United States)

2010-04-28

observed be- tween two ions held in the same trap Eichmann et al., 1993; DeVoe and Brewer, 1996. Type-II links have the advantage of being less sensitive...Childress, E. Jiang, J. Togan, J. Maze, F. Jelezko, A. S. Zibrov, P. R. Hemmer, and M. D. Lukin, 2007, Science 316, 1312. Eichmann , U., J. C. Bergquist

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

Energy Technology Data Exchange (ETDEWEB)

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

2001-07-01

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

Aqueous processing of composite lithium ion electrode material

Science.gov (United States)

Li, Jianlin; Armstrong, Beth L; Daniel, Claus; Wood, III, David L

2015-02-17

A method of making a battery electrode includes the steps of dispersing an active electrode material and a conductive additive in water with at least one dispersant to create a mixed dispersion; treating a surface of a current collector to raise the surface energy of the surface to at least the surface tension of the mixed dispersion; depositing the dispersed active electrode material and conductive additive on a current collector; and heating the coated surface to remove water from the coating.

Aqueous processing of composite lithium ion electrode material

Energy Technology Data Exchange (ETDEWEB)

Li, Jianlin; Armstrong, Beth L.; Daniel, Claus; Wood, III, David L.

2017-06-20

A method of making a battery electrode includes the steps of dispersing an active electrode material and a conductive additive in water with at least one dispersant to create a mixed dispersion; treating a surface of a current collector to raise the surface energy of the surface to at least the surface tension of the mixed dispersion; depositing the dispersed active electrode material and conductive additive on a current collector; and heating the coated surface to remove water from the coating.

Proposed LLNL electron beam ion trap

International Nuclear Information System (INIS)

Marrs, R.E.; Egan, P.O.; Proctor, I.; Levine, M.A.; Hansen, L.; Kajiyama, Y.; Wolgast, R.

1985-01-01

The interaction of energetic electrons with highly charged ions is of great importance to several research fields such as astrophysics, laser fusion and magnetic fusion. In spite of this importance there are almost no measurements of electron interaction cross sections for ions more than a few times ionized. To address this problem an electron beam ion trap (EBIT) is being developed at LLNL. The device is essentially an EBIS except that it is not intended as a source of extracted ions. Instead the (variable energy) electron beam interacting with the confined ions will be used to obtain measurements of ionization cross sections, dielectronic recombination cross sections, radiative recombination cross sections, energy levels and oscillator strengths. Charge-exchange recombinaion cross sections with neutral gasses could also be measured. The goal is to produce and study elements in many different charge states up to He-like xenon and Ne-like uranium. 5 refs., 2 figs

Temperature measurement of {sup 6}He{sup + } ions confined in a transparent Paul trap

Energy Technology Data Exchange (ETDEWEB)

Flechard, X., E-mail: flechard@lpccaen.in2p3.fr; Ban, G.; Durand, D.; Lienard, E.; Mauger, F. [Universite de Caen, LPC Caen, ENSICAEN (France); Mery, A. [Universite de Caen, CIMAP, CEA/CNRS/ENSICAEN (France); Naviliat-Cuncic, O. [Universite de Caen, LPC Caen, ENSICAEN (France); Rodriguez, D. [Universitad de Granada, Departamento de Fisica Atomica, Molecular y Nuclear (Spain); Velten, P. [Universite de Caen, LPC Caen, ENSICAEN (France)

2011-07-15

The LPCTrap setup is a transparent Paul trap dedicated to the measurement of the {beta}-{nu} correlation coefficient a{sub {beta}{nu}} in the {beta} decay of trapped radioactive nuclides. In a first experiment, the system has been used to record {approx}10{sup 5} coincidences between the {beta} particles and recoiling ions emitted from the decay of {sup 6}He{sup + } ions. The analysis of the collected data has already shown that the size of the {sup 6}He{sup + } ion cloud confined in the Paul trap is a critical parameter, potentially limiting the accuracy on the a{sub {beta}{nu}} measurement. We report here the precise determination of the trapped ion cloud temperature and size. This was performed by extracting the trapped ions toward a position sensitive micro channel plate detector at different phases of the RF driving field. We find a temperature T{sub exp} = 0.107(7) eV, consistent with the temperature values inferred using two other observables but 20% higher than the temperature T{sub sim} = 0.09 eV predicted by realistic simulations of the ions interacting with the H{sub 2} buffer gas.

Analytical studies of plasma extraction electrodes and ion beam formation

International Nuclear Information System (INIS)

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

2007-01-01

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

Mercury Trapped Ion Frequency Standard for Ultra-Stable Reference Applications

Science.gov (United States)

Burt, Eric A. (Inventor); Hamell, Robert L. (Inventor); Tucker, Blake C. (Inventor); Larsen, Kameron (Inventor); Tjoelker, Robert L. (Inventor)

2017-01-01

An atomic clock including an ion trap assembly, a C-field coil positioned for generating a first magnetic field in the interrogation region of the ion trap assembly, a compensation coil positioned for generating a second magnetic field in the interrogation region, wherein the combination of the first and second magnetic fields produces an ion number-dependent second order Zeeman shift (Zeeman shift) in the resonance frequency that is opposite in sign to an ion number-dependent second order Doppler shift (Doppler shift) in the resonance frequency, the C-field coil has a radius selected using data indicating how changes in the radius affect an ion-number-dependent shift in the resonance frequency, such that a difference in magnitude between the Doppler shift and the Zeeman shift is controlled or reduced, and the resonance frequency, including the adjustment by the Zeeman shift, is used to obtain the frequency standard.

Surface-modified electrodes (SME)

NARCIS (Netherlands)

Schreurs, J.P.G.M.; Barendrecht, E.

1984-01-01

This review deals with the literature (covered up to August 1983), the characterization and the applications of Surface-Modified Electrodes (SME). As a special class of SME's, the Enzyme-Modified Electrode (EME) is introduced. Three types of modification procedures are distinguished; i.e. covalent

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.

A New Trapped Ion Clock Based on Hg-201(+)

Science.gov (United States)

Taghavi-Larigani, S.; Burt, E. A.; Lea, S. N.; Prestage, J. D.; Tjoelker, R. L.

2009-01-01

There are two stable odd isotopes of mercury with singly ionized hyperfine structure suitable for a microwave clock: Hg-199(+) and Hg-201(+). Virtually all trapped mercury ion clocks to date have used the 199 isotope. We have begun to investigate the viability of a trapped ion clock based on Hg-201(+). We have measured the unperturbed frequency of the (S-2)(sub 1/2) F = 1, m(sub F) = 0 to (S-2)(sub 1/2) F = 2, m(sub F) = 0 clock transition to be 29.9543658211(2) GHz. In this paper we describe initial measurements with Hg-201(+) and new applications to clocks and fundamental physics.

Electrochemical determination of copper ions in spirit drinks using carbon paste electrode modified with biochar.

Science.gov (United States)

Oliveira, Paulo Roberto; Lamy-Mendes, Alyne C; Rezende, Edivaltrys Inayve Pissinati; Mangrich, Antonio Sálvio; Marcolino, Luiz Humberto; Bergamini, Márcio F

2015-03-15

This work describes for first time the use of biochar as electrode modifier in combination with differential pulse adsorptive stripping voltammetric (DPAdSV) techniques for preconcentration and determination of copper (II) ions in spirit drinks samples (Cachaça, Vodka, Gin and Tequila). Using the best set of the experimental conditions a linear response for copper ions in the concentration range of 1.5 × 10(-6) to 3.1 × 10(-5) mol L(-1) with a Limit of Detection (LOD) of 4.0 × 10(-7) mol L(-1). The repeatability of the proposed sensor using the same electrode surface was measured as 3.6% and 6.6% using different electrodes. The effect of foreign species on the voltammetric response was also evaluated. Determination of copper ions content in different samples of spirit drinks samples was also realized adopting inductively coupled plasma optical emission spectroscopy (ICP-OES) and the results achieved are in agreement at a 95% of confidence level. Copyright © 2014 Elsevier Ltd. All rights reserved.

A cryogenic electrostatic trap for long-time storage of keV ion beams

Science.gov (United States)

Lange, M.; Froese, M.; Menk, S.; Varju, J.; Bastert, R.; Blaum, K.; López-Urrutia, J. R. Crespo; Fellenberger, F.; Grieser, M.; von Hahn, R.; Heber, O.; Kühnel, K.-U.; Laux, F.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Schröter, C. D.; Schwalm, D.; Shornikov, A.; Sieber, T.; Toker, Y.; Ullrich, J.; Wolf, A.; Zajfman, D.

2010-05-01

We report on the realization and operation of a fast ion beam trap of the linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature and residual gas density and, hence, long storage times of more than 5 min which are unprecedented for keV ion beams. Inside a beam pipe that can be cooled to temperatures <15 K, with 1.8 K reached in some locations, an ion beam pulse can be stored at kinetic energies of 2-20 keV between two electrostatic mirrors. Along with an overview of the cryogenic trap design, we present a measurement of the residual gas density inside the trap resulting in only 2×103 cm-3, which for a room temperature environment corresponds to a pressure in the 10-14 mbar range. The device, called the cryogenic trap for fast ion beams, is now being used to investigate molecules and clusters at low temperatures, but has also served as a design prototype for the cryogenic heavy-ion storage ring currently under construction at the Max-Planck Institute for Nuclear Physics.

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

Graphene-based integrated electrodes for flexible lithium ion batteries

International Nuclear Information System (INIS)

Shi, Ying; Wen, Lei; Zhou, Guangmin; Chen, Jing; Pei, Songfeng; Huang, Kun; Cheng, Hui-Ming; Li, Feng

2015-01-01

We have prepared flexible free-standing electrodes with anode and cathode active materials deposited on a highly conductive graphene membrane by a two-step filtration method. Compared with conventional electrodes using metal as current collectors, these electrodes have displayed stronger adhesion, superior electrochemical performance, higher energy density, and better flexibility. A full lithium ion battery assembled by adopting these graphene-based electrodes has showed high rate capability and long cyclic life. We have also assembled a thin, lightweight, and flexible lithium ion battery with poly-(dimethyl siloxane) sheets as packaging material to light a red light-emitting diode. This flexible battery can be easily bent without structural failure or performance loss and operated well under a bent state. The fabrication process of these graphene-based integrated electrodes only has two filtration steps; thus it is easy to scale up. These results suggest great potential for these graphene-based flexible batteries in lightweight, bendable, and wearable electronic devices. (paper)

Sympathetic cooling and crystallization of ions in a linear Paul trap

International Nuclear Information System (INIS)

Drewsen, M.; Bowe, P.; Hornekaer, L.; Brodersen, C.; Schiffer, J.P.; Hangst, J.S.; Schiffer, J.P.

1999-01-01

Coulomb crystals, containing up to a few hundred ions of which more than 50% were cooled sympathetically by the Coulomb interaction with laser cooled Mg + ions, have been produced in a linear Paul trap. By controlling the balance of the radiation pressure from the two cooling lasers, the Coulomb crystals could be segregated according to ion species. Previous studies of ion crystals and molecular dynamics simulations suggest that the temperature may be around 10 mK or lower. The obtained results indicate that a wide range of atomic and molecular ions, which due to their internal structures are not amenable to direct laser cooling, can be effectively cooled and localized (crystallized) in linear Paul traps. For high resolution spectroscopy of such ions this may turn out to be very useful. copyright 1999 American Institute of Physics

The effects of surface modification on carbon felt electrodes for use in vanadium redox flow batteries

International Nuclear Information System (INIS)

Kim, Ki Jae; Kim, Young-Jun; Kim, Jae-Hun; Park, Min-Sik

2011-01-01

Highlights: ► We observed the physical and chemical changes on the surface of carbon felts after various surface modifications. ► The surface area and chemistry of functional groups formed on the surface of carbon felt are critical to determine the kinetics of the redox reactions of vanadium ions. ► By incorporation of the surface modifications into the electrode preparation, the electrochemical activity of carbon felts could be notably enhanced. - Abstract: The surface of carbon felt electrodes has been modified for improving energy efficiency of vanadium redox flow batteries. For comparative purposes, the effects of various surface modifications such as mild oxidation, plasma treatment, and gamma-ray irradiation on the electrochemical properties of carbon felt electrodes were investigated at optimized conditions. The cell energy efficiency was improved from 68 to 75% after the mild oxidation of the carbon felt at 500 °C for 5 h. This efficiency improvement could be attributed to the increased surface area of the carbon felt electrode and the formation of functional groups on its surface as a result of the modification. On the basis of various structural and electrochemical characterizations, a relationship between the surface nature and electrochemical activity of the carbon felt electrodes is discussed.

A Penning trap for advanced studies with particles in extreme laser fields

International Nuclear Information System (INIS)

Vogel, M.; Quint, W.; Paulus, G.G.; Stöhlker, Th.

2012-01-01

We present a Penning trap as a tool for advanced studies of particles in extreme laser fields. Particularly, trap-specific manipulation techniques allow control over the confined particles’ localization and spatial density by use of trap electrodes as ‘electrostatic tweezers’ and by application of a ‘rotating wall’, respectively. It is thereby possible to select and prepare well-defined ion ensembles and to optimize the laser–particle interaction. Non-destructive detection of reaction educts and products with up to single-ion sensitivity supports advanced studies by maintaining the products for further studies at extended confinement times of minutes and above. The trap features endcaps with conical openings for applications with strongly focused lasers. We show that such a modification of a cylindrical trap is possible while harmonicity and tunability are maintained.

A Penning trap for advanced studies with particles in extreme laser fields

Science.gov (United States)

Vogel, M.; Quint, W.; Paulus, G. G.; Stöhlker, Th.

2012-08-01

We present a Penning trap as a tool for advanced studies of particles in extreme laser fields. Particularly, trap-specific manipulation techniques allow control over the confined particles' localization and spatial density by use of trap electrodes as 'electrostatic tweezers' and by application of a 'rotating wall', respectively. It is thereby possible to select and prepare well-defined ion ensembles and to optimize the laser-particle interaction. Non-destructive detection of reaction educts and products with up to single-ion sensitivity supports advanced studies by maintaining the products for further studies at extended confinement times of minutes and above. The trap features endcaps with conical openings for applications with strongly focused lasers. We show that such a modification of a cylindrical trap is possible while harmonicity and tunability are maintained.

Mass-selective isolation of ions stored in a quadrupole ion trap. A simulation study

Science.gov (United States)

March, Raymond E.; Londry, Frank A.; Alfred, Roland L.; Franklin, Anthony M.; Todd, John F. J.

1992-01-01

Trajectories of single ions stored in the quadrupole ion trap have been calculated using a simulation program described as the specific program for quadrupolar resonance (SPQR). Previously, the program has been used for the investigation of quadrupolar resonance excitation of ions with a static working point (or co-ordinates) in the stability diagram. The program has been modified to accommodate continuous d.c. and/or r.f. voltage ramps so as to permit calculation of ion trajectories while the working point is being changed. The modified program has been applied to the calculation of ion trajectories during ion isolation, or mass-selective storage, in the ion trap. The quadrupolar resonance excitation aspect of SPQR was not used in this study. Trajectories are displayed as temporal variations of ion kinetic energy, and axial and radial excursions from the centre of the ion trap. The working points of three ion species (m/z 144, 146 and 148), located initially on the qz, axis with qz [approximate] 0.12, were moved to the vicinity of the upper apex by a combination of r.f. and d.c. voltages applied in succession. Stable trajectories were maintained only for the ion species of m/z 146 for which the working point lay within this apex; the other ion species were ejected either radially or axially. The d.c. voltage was then reduced to zero so as to restore the working point of the isolated ion species to the qz axis. The amplitude of the r.f voltage was reduced to its initial value so as to retrieve the initial working point for m/z 146. The process extended over a real time of 2.9 ms, and was collision-free. The trajectory of the isolated ion was stable during this process; the ion species with m/z value lower than that of the target ion, that is, m/z 144, was ejected axially at the [beta]z = 1 boundary, while that with higher m/z value, that is, m/z 148, was ejected radially at the [beta]r = 0 boundary, as expected. The moderating effects of buffer gas were not taken

A review of laser electrode processing for development and manufacturing of lithium-ion batteries

Science.gov (United States)

Pfleging, Wilhelm

2018-02-01

Laser processes for cutting, annealing, structuring, and printing of battery materials have a great potential in order to minimize the fabrication costs and to increase the electrochemical performance and operational lifetime of lithium-ion cells. Hereby, a broad range of applications can be covered such as micro-batteries, mobile applications, electric vehicles, and stand-alone electric energy storage devices. Cost-efficient nanosecond (ns)-laser cutting of electrodes was one of the first laser technologies which were successfully transferred to industrial high-energy battery production. A defined thermal impact can be useful in electrode manufacturing which was demonstrated by laser annealing of thin-film electrodes for adjusting of battery active crystalline phases or by laser-based drying of composite thick-film electrodes for high-energy batteries. Ultrafast or ns-laser direct structuring or printing of electrode materials is a rather new technical approach in order to realize three-dimensional (3D) electrode architectures. Three-dimensional electrode configurations lead to a better electrochemical performance in comparison to conventional 2D one, due to an increased active surface area, reduced mechanical tensions during electrochemical cycling, and an overall reduced cell impedance. Furthermore, it was shown that for thick-film composite electrodes an increase of electrolyte wetting could be achieved by introducing 3D micro-/nano-structures. Laser structuring can turn electrodes into superwicking. This has a positive impact regarding an increased battery lifetime and a reliable battery production. Finally, laser processes can be up-scaled in order to transfer the 3D battery concept to high-energy and high-power lithium-ion cells.

The control mechanism of surface traps on surface charge behavior in alumina-filled epoxy composites

International Nuclear Information System (INIS)

Li, Chuanyang; Hu, Jun; Lin, Chuanjie; He, Jinliang

2016-01-01

To investigate the role surface traps play in the charge injection and transfer behavior of alumina-filled epoxy composites, surface traps with different trap levels are introduced by different surface modification methods which include dielectric barrier discharges plasma, direct fluorination, and Cr 2 O 3 coating. The resulting surface physicochemical characteristics of experimental samples were observed using atomic force microscopy, scanning electron microscopy and fourier transform infrared spectroscopy. The surface potential under dc voltage was detected and the trap level distribution was measured. The results suggest that the surface morphology of the experimental samples differs dramatically after treatment with different surface modification methods. Different surface trap distributions directly determine the charge injection and transfer property along the surface. Shallow traps with trap level of 1.03–1.11 eV and 1.06–1.13 eV introduced by plasma and fluorination modifications are conducive for charge transport along the insulating surface, and the surface potential can be modified, producing a smoother potential curve. The Cr 2 O 3 coating can introduce a large number of deep traps with energy levels ranging from 1.09 to 1.15 eV. These can prevent charge injection through the reversed electric field formed by intensive trapped charges in the Cr 2 O 3 coatings. (paper)

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

International Nuclear Information System (INIS)

Kurita, Tetsuro; Nakagawa, Takahide; Kidera, Masanori

1999-01-01

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

Generation of H-, H2(v double-prime), and H atoms by H2+ and H3+ ions incident upon barium surfaces

International Nuclear Information System (INIS)

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

1989-01-01

The generation of vibrationally excited molecules by electron excitation collisions and the subsequent generation of negative ions by dissociative attachment to these molecules has become a standard model for volume source operation. These processes have been supplemented recently by the demonstration of atom-surface recombination to form vibrationally excited molecules, and enhanced negative ion formation by protons incident upon barium electrodes. In this paper we consider the additional processes of molecular vibrational excitation generated by recombination of molecular ions on the electrode surfaces, and negative ion formation by vibrationally excited molecules rebounding from low work-function electrodes. 10 refs., 4 figs

Scheme for teleportation of unknown states of trapped ion

Institute of Scientific and Technical Information of China (English)

Chen Mei-Feng; Ma Song-She

2008-01-01

A scheme is presented for teleporting an unknown state in a trapped ion system.The scheme only requires a single laser beam.It allows the trap to be in any state with a few phonons,e.g.a thermal motion.Furthermore,it works in the regime,where the Rabi frequency of the laser is on the order of the trap frequency.Thus,the teleportation speed is greatly increased,which is important for decreasing the decoherence effect.This idea can also be used to teleport an unknown ionic entangled state.

The nonlinear dustgrain-charging on large amplitude electrostatic waves in a dusty plasma with trapped ions

Directory of Open Access Journals (Sweden)

Y.-N. Nejoh

1998-01-01

Full Text Available The nonlinear dustgrain-charging and the influence of the ion density and temperature on electrostatic waves in a dusty plasma having trapped ions are investigated by numerical calculation. This work is the first approach to the effect of trapped ions in dusty plasmas. The nonlinear variation of the dust-charge is examined, and it is shown that the characteristics of the dustcharge number sensitively depend on the plasma potential, Mach number, dust mass-to-charge ratio, trapped ion density and temperature. The fast and slow wave modes are shown in this system. An increase of the ion temperature decreases the dust-charging rate and the propagation speed of ion waves. It is found that the existence of electrostatic ion waves sensitively depends on the ion to electron density ratio. New findings of the variable-charge dust grain particles, ion density and temperature in a dusty plasma with trapped ions are predicted.

Penning-trap mass spectrometry of radioactive, highly charged ions. Measurements of neutron-rich Rb and Sr nuclides for nuclear astrophysics and development of a novel Penning trap for cooling highly charged ions

International Nuclear Information System (INIS)

Simon, Vanessa Veronique

2012-01-01

High-precision atomic mass measurements are vital for the description of nuclear structure, investigations of nuclear astrophysical processes, and tests of fundamental symmetries. The neutron-rich A ∼ 100 region presents challenges for modeling the astrophysical r-process because of sudden nuclear shape transitions. This thesis reports on high-precision masses of short-lived neutron-rich 94,97,98 Rb and 94,97-99 Sr isotopes using the TITAN Penning-trap mass spectrometer at TRIUMF. The isotopes were charge-bred to q = 15+; uncertainties of less than 4 keV were achieved. Results deviate by up to 11σ compared to earlier measurements and extend the region of nuclear deformation observed in the A∼100 region. A parameterized r-process model network calculation shows that mass uncertainties for the elemental abundances in this region are now negligible. Although beneficial for the measurement precision, the charge breeding process leads to an increased energy spread of the ions on the order of tens of eV/q. To eliminate this drawback, a Cooler Penning Trap (CPET) has been developed as part of this thesis. The novel multi-electrode trap structure of CPET forms nested potentials to cool HCI sympathetically using either electrons or protons to increase the overall efficiency and precision of the mass measurement. The status of the off-line setup and initial commissioning experiments are presented.

Changes in the surface electronic states of semiconductor fine particles induced by high energy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Yamaki, Tetsuya; Asai, Keisuke; Ishigure, Kenkichi [Tokyo Univ. (Japan); Shibata, Hiromi

1997-03-01

The changes in the surface electronic states of Q-sized semiconductor particles in Langmuir-Blodgett (LB) films, induced by high energy ion irradiation, were examined by observation of ion induced emission and photoluminescence (PL). Various emission bands attributed to different defect sites in the band gap were observed at the initial irradiation stage. As the dose increased, the emissions via the trapping sites decreased in intensity while the band-edge emission developed. This suggests that the ion irradiation would remove almost all the trapping sites in the band gap. The low energy emissions, which show a multiexponential decay, were due to a donor-acceptor recombination between the deeply trapped carriers. It was found that the processes of formation, reaction, and stabilization of the trapping sites would predominantly occur under the photooxidizing conditions. (author)

A simple model for the trapping of deuterons in a carbon target

International Nuclear Information System (INIS)

Erents, S.K.; Hotston, E.S.

1980-01-01

A model is proposed for the trapping of deuterons in an annealed carbon target. The deuterons are assumed to be lodged in traps which are created by the ion beam implanting the deuterons. There is a saturation trap density of 6.8 x 10 22 cm -3 . A deuteron in a region of the target where all the traps are filled is free to execute a random walk until it finds a vacant trap or is released from the target surface. The number of ions trapped per unit area of the target surface has been calculated as a function of ion fluence and is in good agreement with the experimental results. (orig.)

Tracking metal ions with polypyrrole thin films adhesively bonded to diazonium-modified flexible ITO electrodes.

Science.gov (United States)

Lo, Momath; Diaw, Abdou K D; Gningue-Sall, Diariatou; Aaron, Jean-Jacques; Oturan, Mehmet A; Chehimi, Mohamed M

2018-05-09

Adhesively bonded polypyrrole thin films doped with benzene sulfonic acid (BSA) were electrodeposited on aminobenzenediazonium-modified flexible ITO electrodes and further employed for the detection of Pb 2+ , Cu 2+ , and Cd 2+ metal ions in aqueous medium. The aminophenyl (AP) adhesive layer was grafted to ITO by electroreduction of the in situ generated parent diazonium compound. Polypyrrole (PPy) thin films exhibited remarkable adhesion to aminophenyl (ITO-AP). The strongly adherent polypyrrole films exhibited excellent electroactivity in the doped state with BSA which itself served to chelate the metal ions in aqueous medium. The surface of the resulting, modified flexible electrode was characterized by XPS, SEM, and electrochemical methods. The ITO-AP-PPy electrodes were then used for the simultaneous detection of Cu 2+ , Cd 2+ , and Pb 2+ by differential pulse voltammetry (DPV). The detection limits were 11.1, 8.95, and 0.99 nM for Cu 2+ , Cd 2+ , and Pb 2+ , respectively. In addition, the modified electrodes displayed a good reproducibility, making them suitable for the determination of heavy metals in real wastewater samples.

Fluorescence profiles and cooling dynamics of laser-cooled Mg+ ions in a linear rf ion trap

International Nuclear Information System (INIS)

Zhao Xianzhen; Ryjkov, Vladimir L.; Schuessler, Hans A.

2006-01-01

Fluorescence line profiles and their implications on the cooling dynamics of the Mg + ions stored in a linear rf trap are studied. The line profile is dictated by the temperature of the ion cloud at different laser detunings. The upper bound of the lowest temperature was estimated for different values of the rf trapping potential amplitude and the buffer gas pressure. A general trend of this ultimate temperature to increase with the rf trapping voltage and buffer gas pressure is expected, with an abrupt change at some critical value corresponding to the transition to and from a strongly correlated liquid or crystal state. While on the one hand this expectation was confirmed when the buffer gas pressure was varied; on the other hand the influence of the amplitude of the trapping voltage on the ultimate temperature shows an interesting new feature of first dipping down before the sharp increase occurs

Quantum Information Processing with Trapped Ions

International Nuclear Information System (INIS)

Barrett, M.D.; Schaetz, T.; Chiaverini, J.; Leibfried, D.; Britton, J.; Itano, W.M.; Jost, J.D.; Langer, C.; Ozeri, R.; Wineland, D.J.; Knill, E.

2005-01-01

We summarize two experiments on the creation and manipulation of multi-particle entangled states of trapped atomic ions - quantum dense coding and quantum teleportation. The techniques used in these experiments constitute an important step toward performing large-scale quantum information processing. The techniques also have application in other areas of physics, providing improvement in quantum-limited measurement and fundamental tests of quantum mechanical principles, for example

Numerical simulation of injection and resistive trapping of ion rings

International Nuclear Information System (INIS)

Mankofsky, A.; Friedman, A.; Sudan, R.N.

1981-01-01

Numerical studies of the injection and resistive trapping efficiency of ion rings, using an improved algorithm are presented. Trapping efficiency is found to be strongly dependent upon the number of particles injected and upon mirror ratios in the system. Wall resistivity and beam divergence affect the process to a lesser extent. (author)

An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies

International Nuclear Information System (INIS)

Schowalter, Steven J.; Chen Kuang; Rellergert, Wade G.; Sullivan, Scott T.; Hudson, Eric R.

2012-01-01

We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates.

A cryogenic electrostatic trap for long-time storage of keV ion beams.

Science.gov (United States)

Lange, M; Froese, M; Menk, S; Varju, J; Bastert, R; Blaum, K; López-Urrutia, J R Crespo; Fellenberger, F; Grieser, M; von Hahn, R; Heber, O; Kühnel, K-U; Laux, F; Orlov, D A; Rappaport, M L; Repnow, R; Schröter, C D; Schwalm, D; Shornikov, A; Sieber, T; Toker, Y; Ullrich, J; Wolf, A; Zajfman, D

2010-05-01

We report on the realization and operation of a fast ion beam trap of the linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature and residual gas density and, hence, long storage times of more than 5 min which are unprecedented for keV ion beams. Inside a beam pipe that can be cooled to temperatures <15 K, with 1.8 K reached in some locations, an ion beam pulse can be stored at kinetic energies of 2-20 keV between two electrostatic mirrors. Along with an overview of the cryogenic trap design, we present a measurement of the residual gas density inside the trap resulting in only 2 x 10(3) cm(-3), which for a room temperature environment corresponds to a pressure in the 10(-14) mbar range. The device, called the cryogenic trap for fast ion beams, is now being used to investigate molecules and clusters at low temperatures, but has also served as a design prototype for the cryogenic heavy-ion storage ring currently under construction at the Max-Planck Institute for Nuclear Physics.

Porous graphite electrodes for rechargeable ion-transfer batteries

Energy Technology Data Exchange (ETDEWEB)

Novak, P; Scheifele, W; Haas, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

The influence of preparation pressure and pore-forming additives on the properties of graphite-based, Li{sup +}-intercalating electrodes for ion-transfer batteries have been investigated. The electrochemical performance of graphite electrodes could be improved by adjusting the porosity. Specific charge of >300 Ah/kg (with respect to the graphite mass) could be achieved. (author) 4 figs., 2 refs.

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Simulation of the elementary evolution operator with the motional states of an ion in an anharmonic trap

Energy Technology Data Exchange (ETDEWEB)

Santos, Ludovic; Vaeck, Nathalie [Laboratoire de Chimie Quantique et Photophysique, CP 160/09 Université Libre de Bruxelles, B-1050 Brussels (Belgium); Justum, Yves [Laboratoire de Chimie Physique, UMR 8000 and CNRS, Université Paris-Sud, F-91405 Orsay (France); Desouter-Lecomte, M. [Laboratoire de Chimie Physique, UMR 8000 and CNRS, Université Paris-Sud, F-91405 Orsay (France); Département de Chimie, Université de Liège, Bât B6c, Sart Tilman B-4000, Liège (Belgium)

2015-04-07

Following a recent proposal of L. Wang and D. Babikov [J. Chem. Phys. 137, 064301 (2012)], we theoretically illustrate the possibility of using the motional states of a Cd{sup +} ion trapped in a slightly anharmonic potential to simulate the single-particle time-dependent Schrödinger equation. The simulated wave packet is discretized on a spatial grid and the grid points are mapped on the ion motional states which define the qubit network. The localization probability at each grid point is obtained from the population in the corresponding motional state. The quantum gate is the elementary evolution operator corresponding to the time-dependent Schrödinger equation of the simulated system. The corresponding matrix can be estimated by any numerical algorithm. The radio-frequency field which is able to drive this unitary transformation among the qubit states of the ion is obtained by multi-target optimal control theory. The ion is assumed to be cooled in the ground motional state, and the preliminary step consists in initializing the qubits with the amplitudes of the initial simulated wave packet. The time evolution of the localization probability at the grids points is then obtained by successive applications of the gate and reading out the motional state population. The gate field is always identical for a given simulated potential, only the field preparing the initial wave packet has to be optimized for different simulations. We check the stability of the simulation against decoherence due to fluctuating electric fields in the trap electrodes by applying dissipative Lindblad dynamics.

Selectivity coefficients of ion-selective magnesium electrodes used for simultaneous determination of magnesium and calcium ions.

Science.gov (United States)

Maj-Zurawska, Magdalena; Lewenstam, Andrzej

2011-12-15

Membrane ion-selective magnesium electrodes are commonly used to determine ionized magnesium concentration in blood serum and intracellular fluid by potentiometric clinical analyzers. The selectivity of these electrodes against calcium ion is typically insufficient to avoid calcium interference in blood serum analysis. For this reason the selectivity coefficient for calcium ion has to be studied to make possible any mathematical corrections for calcium ion influence. Existing methods relate to the thermodynamic concept of ISE response which suggest a single constant value of the selectivity coefficient and slope that are stable over the concentration ranges of calcium and magnesium ions in the samples. Unfortunately, this rarely happens, and we rather observe dependences on solution and membrane composition, readout time, matrices (anticoagulant, vial coats) that justify usage of apparent selectivities and slopes. To get the practical insight into the response of magnesium ion-selective electrodes a novel method for estimating the selectivity coefficients and the slope of the electrode characteristics is proposed. This method is an effective starting point for selecting electrodes and designing transient signal software in a potentiometric clinical analyzer. The method allows obtaining the ionized magnesium concentration in blood serum with minimal possible error by addressing the assessed targets, i.e. apparent selectivity and slope. The method is based on computer simulation and on the Nicolsky-Eisenman equation. Usually only a few iterations are needed to obtain stable congruent results. The method presented is particularly useful in conditions where is not possible to obtain calibration curve, which is typical for clinical analyzer where at most three point calibration is performed. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of an in-trap spectroscopy setup at MLLTRAP for the future project MATS at FAIR

Energy Technology Data Exchange (ETDEWEB)

Thirolf, Peter; Gartzke, Eva; Habs, Dietrich; Krug, Kevin; Szerypo, Jerzy; Weber, Christine [Fak. fuer Physik, LMU - Muenchen (Germany); Kolhinen, Veli [Dept. of Physics, University of Jyvaeskylae (Sweden); Rodriguez, Daniel [FAMN, Universidad de Granada (Spain)

2010-07-01

One of the most important achievements of Penning trap technology is the possibility to manipulate ions of a defined q/m in order to provide purified ion species to dedicated experiments, such as high-precision mass measurements. This feature of ion manipulation and purification is used as well in nuclear decay-spectroscopy experiments with isobarically or even isomerically pure samples, typically installed after the trap. In a further approach, the Penning trap itself is equipped with detectors, since the stored ion clouds represent ideal sources, free from any background or scattering effects in the required backing materials. An in-trap spectroscopy setup is developed at MLLTRAP to be implemented in the future MATS facility at the low-energy branch of FAIR/GSI. Here, the main trapping electrodes will be replaced by position-sensitive Si-strip detectors and emitted electrons are efficiently guided towards detectors by the strong field of the trap magnet. Possible physics experiments are conversion-electron spectroscopy and in-trap {alpha}-decay experiments of heavy actinides. In this presentation, the design of the setup and possible physics applications are presented.