WorldWideScience

Sample records for high energy ring

  1. Low energy current accumulator for high-energy proton rings

    International Nuclear Information System (INIS)

    Month, M.

    1977-01-01

    Building current in high-energy p-p colliding beam machines is most appropriately done in a low-energy (small circumference) current accumulator. Three significant factors favor such a procedure: First, large rings tend to be susceptible to unstable longitudinal density oscillations. These can be avoided by pumping up the beam in the accumulator. When the current stack is injected into the storage ring, potentially harmful instability is essentially neutralized. Second, high-field magnets characteristic of future high energy proton rings are designed with superconducting coils within the iron magnetic shield. This means coil construction and placement errors propagate rapidly within the beam aperture. An intermediate ''stacking ring'' allows the minimum use of the superconducting ring aperture. Finally, the coils are vulnerable to radiation heating and possible magnet quenching. By minimizing beam manipulaion in the superconducting environment and using only the central portion of the beam aperture, coil vulnerability can be put at a minimum

  2. Beam Commissioning of the PEP-II High Energy Ring

    International Nuclear Information System (INIS)

    Wienands, U.; Anderson, S.; Assmann, R.; Bharadwaj, V.; Cai, Y.; Clendenin, J.; Corredoura, P.; Decker, F.J.; Donald, M.; Ecklund, S.; Emma, P.; Erickson, R.; Fox, J.; Fieguth, T.; Fisher, A.; Heifets, S.; Hill, A.; Himel, T.; Iverson, R.; Johnson, R.; Judkins, J.; Krejcik, P.; Kulikov, A.; Lee, M.; Mattison, T.; Minty, M.; Nosochkov, Y.; Phinney, N.; Placidi, M.; Prabhakar, S.; Ross, M.; Smith, S.; Schwarz, H.; Stanek, M.; Teytelman, D.; Traller, R.; Turner, J.; Zimmermann, F.; Barry, W.; Chattopadhyay, S.; Corlett, J.; Decking, W.; Furman, M.; Nishimura, H.; Portmann, G.; Rimmer, R.; Zholents, A.; Zisman, M.; Kozanecki, W.; Hofmann, A.; Zotter, B.; Steier, C.; Bialowons, W.; Lomperski, M.; Lumpkin, A.; Reichel, I.; Safranek, J.; Smith, V.; Tighe, R.; Sullivan, M.; Byrd, J.; Li, D.

    1998-01-01

    The PEP-II High Energy Ring (HER), a 9 GeV electron storage ring, has been in commissioning since spring 1997. Initial beam commissioning activities focused on systems checkout and commissioning and on determining the behavior of the machine systems at high beam currents. This phase culminated with the accumulation of 0.75 A of stored beam-sufficient to achieve design luminosity--in January 1998 after 3.5 months of beam time. Collisions with the 3 GeV positron beam of the Low Energy Ring (LER) were achieved in Summer of 1998. At high beam currents, collective instabilities have been seen. Since then, commissioning activities for the HER have shifted in focus towards characterization of the machine and a rigorous program to understand the machine and the beam dynamics is presently underway

  3. Status of the PEP-II B-factory high energy ring

    International Nuclear Information System (INIS)

    Wienands, U.; Reuter, E.; Bellomo, P.; Daly, E.; Fisher, A.; Gracia, J.; Kulikov, A.; Kurita, N.; Pietryka, M.; Seeman, J.T.; Taylor; Belser, C.; Bertolini, L.; Mugge, M.; Swan, J.

    1996-01-01

    The 9 GeV High Energy Ring (HER) of the PEP-II B Factory is an electron storage ring under construction at SLAC. Significant progress has been made in the last year on all systems. As of mid 1996, all 192 dipoles have been installed, with installation of the quadrupoles underway. The vacuum system, for design currents up to 3 A average, is in production using a recently commissioned e-beam welder. Beam instrumentation systems are being fabricated. The interaction region will bring the HER beam into collision with the 3 GeV beam of the Low Energy Ring; design of this section of the HER is in an advanced stage. 8 refs., 3 figs., 1 tab

  4. Polarized beams in high energy storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Montague, B W [European Organization for Nuclear Research, Geneva (Switzerland)

    1984-11-01

    In recent years there has been a considerable advance in understanding the spin motion of particles in storage rings and accelerators. The survey presented here outlines the early historical development in this field, describes the basic ideas governing the kinetics of polarized particles in electromagnetic fields and shows how these have evolved into the current description of polarized beam behaviour. Orbital motion of particles influences their spin precession, and depolarization of a beam can result from excitation of spin resonances by orbit errors and oscillations. Electrons and positrons are additionally influenced by the quantized character of synchrotron radiation, which not only provides a polarizing mechanism but also enhances depolarizing effects. Progress in the theoretical formulation of these phenomena has clarified the details of the physical processes and suggested improved methods of compensating spin resonances. Full use of polarized beams for high-energy physics with storage rings requires spin rotators to produce longitudinal polarization in the interaction regions. Variants of these schemes, dubbed Siberian snakes, provide a curious precession topology which can substantially reduce depolarization in the high-energy range. Efficient polarimetry is an essential requirement for implementing polarized beams, whose utility for physics can be enhanced by various methods of spin manipulation.

  5. SPARC experiments at the high-energy storage ring

    International Nuclear Information System (INIS)

    Stöhlker, Thomas; Litvinov, Yuri A; Bagnoud, Vincent; Dimopoulou, Christina; Dolinskii, Alexei; Geppert, Christopher; Hagmann, Siegbert; Katayama, Takeshi; Kühl, Thomas; Nörtershäuser, Wilfried; Steck, Markus; Bechstedt, Ulf; Maier, Rudolf; Prasuhn, Dieter; Stockhorst, Hans; Schuch, Reinhold

    2013-01-01

    The physics program of the SPARC collaboration at the Facility for Antiproton and Ion Research (FAIR) focuses on the study of collision phenomena in strong and even extreme electromagnetic fields and on the fundamental interactions between electrons and heavy nuclei up to bare uranium. Here we give a short overview on the challenging physics opportunities of the high-energy storage ring at FAIR for future experiments with heavy-ion beams at relativistic energies with particular emphasis on the basic beam properties to be expected. (paper)

  6. Modeling and Simulation of Longitudinal Dynamics for Low Energy Ring-High Energy Ring at the Positron-Electron Project

    International Nuclear Information System (INIS)

    Rivetta, Claudio; Mastorides, T.; Fox, J.D.; Teytelman, D.; Van Winkle, D.

    2007-01-01

    A time domain dynamic modeling and simulation tool for beam-cavity interactions in the Low Energy Ring (LER) and High Energy Ring (HER) at the Positron-Electron Project (PEP-II) is presented. Dynamic simulation results for PEP-II are compared to measurements of the actual machine. The motivation for this tool is to explore the stability margins and performance limits of PEP-II radio-frequency (RF) systems at future higher currents and upgraded RF configurations. It also serves as a test bed for new control algorithms and can define the ultimate limits of the low-level RF (LLRF) architecture. The time domain program captures the dynamic behavior of the beam-cavity-LLRF interaction based on a reduced model. The ring current is represented by macrobunches. Multiple RF stations in the ring are represented via one or two macrocavities. Each macrocavity captures the overall behavior of all the 2 or 4 cavity RF stations. Station models include nonlinear elements in the klystron and signal processing. This enables modeling the principal longitudinal impedance control loops interacting via the longitudinal beam model. The dynamics of the simulation model are validated by comparing the measured growth rates for the LER with simulation results. The simulated behavior of the LER at increased operation currents is presented via low-mode instability growth rates. Different control strategies are compared and the effects of both the imperfections in the LLRF signal processing and the nonlinear drivers and klystrons are explored

  7. Analysis of possibilities for a spin flip in high energy electron ring HERA

    International Nuclear Information System (INIS)

    Stres, S.; Pestotnik, R.

    2007-01-01

    In a high energy electron ring the spins of electrons become spontaneously polarized via the emission of spin-flip synchrotron radiation. By employing a radio frequency (RF) radial dipole field kicker, particle spin directions can be rotated slowly over many turns. A model which couples three dimensional spin motion and longitudinal particle motion was constructed to describe non-equilibrium spin dynamics in high energy electron storage rings. The effects of a stochastic synchrotron radiation on the orbital motion in the accelerator synchrotron plane and its influence on the spin motion are studied. The main contributions to the spin motion, the synchrotron oscillations and the stochastic synchrotron radiation, have different influence on the spin polarization reversal in different regions of the parameter space. The results indicate that polarization reversal might be obtained in high energy electron storage rings with a significant noise even with relatively small strengths of a perturbing magnetic field. The only experimental datum avaliable agrees with the model prediction, however further experimental data would be necessary to validate the model

  8. Beam loading in high-energy storage rings

    International Nuclear Information System (INIS)

    Wilson, P.B.

    1974-06-01

    The analysis of beam loading in the RF systems of high-energy storage rings (for example, the PEP e/sup /minus//e/sup +/ ring) is complicated by the fact that the time, T/sub b/, between the passage of successive bunches is comparable to the cavity filling time, T/sub b/. In this paper, beam loading expressions are first summarized for the usual case in which T/sub b/ /much lt/ T/sub f/. The theory of phase oscillations in the heavily-beam-loaded case is considered, and the dependence of the synchrotron frequency and damping constant for the oscillations on beam current and cavity tuning is calculated. Expressions for beam loading are then derived which are valid for any value of the ratio T/sub b//T/sub f/. It is shown that, for the proposed PEP e/sup /minus//e/sup +/ ring parameters, the klystron power required is increased by about 3% over that calculated using the standard beam loading expressions. Finally, the analysis is extended to take into account the additional losses associated with the excitation of higher-order cavity modes. A rough numerical estimate is made of the loss enhancement to be expected for PEP RF system. It is concluded that this loss enhancement might be substantial unless appropriate measures are taken in the design and tuning of the accelerating structure

  9. Properties of the electron cloud in a high-energy positron and electron storage ring

    International Nuclear Information System (INIS)

    Harkay, K.C.; Rosenberg, R.A.

    2003-01-01

    Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in a positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.

  10. High-energy terahertz wave parametric oscillator with a surface-emitted ring-cavity configuration.

    Science.gov (United States)

    Yang, Zhen; Wang, Yuye; Xu, Degang; Xu, Wentao; Duan, Pan; Yan, Chao; Tang, Longhuang; Yao, Jianquan

    2016-05-15

    A surface-emitted ring-cavity terahertz (THz) wave parametric oscillator has been demonstrated for high-energy THz output and fast frequency tuning in a wide frequency range. Through the special optical design with a galvano-optical scanner and four-mirror ring-cavity structure, the maximum THz wave output energy of 12.9 μJ/pulse is achieved at 1.359 THz under the pump energy of 172.8 mJ. The fast THz frequency tuning in the range of 0.7-2.8 THz can be accessed with the step response of 600 μs. Moreover, the maximum THz wave output energy from this configuration is 3.29 times as large as that obtained from the conventional surface-emitted THz wave parametric oscillator with the same experimental conditions.

  11. Rf systems for high-energy e/sup /minus//e/sup /plus// storage rings

    International Nuclear Information System (INIS)

    Allen, M.A.; Wilson, P.B.

    1974-01-01

    Electron or positron beams in a storage ring radiate electromagnetic energy at a rate proportional to the fourth power of the recirculating energy, and this loss must be supplied by an rf system. Furthermore, a substantial overvoltage is required to contain the stored beam against losses due to quantum fluctuations in the emitted photons. As an example, an improvement program, SPEAR II, is now underway to increase the energy of the SPEAR ring to 4.5 GeV. At this energy, the radiation loss per turn is 2.8 MeV, and to maintain a reasonable lifetime against quantum fluctuations, a peak voltage of 7.5 MeV is required. Thus, the SPEAR II rf system is similar to a continuously-operating 7.5 MeV linear accelerator. Furthermore, the available straight-section space in the ring which is suitable for containing the accelerating structures is limited, and this means that a cavity design must be sought with a high shunt impedance per losses will be held to a reasonable level. In the case of SPEAR, about 9 meters of straight section space is available for accelerating cavities, requiring a gradient of close to 1 MV per meter. The PEP 15-GeV ring would require peak accelerating voltages of around 50 MV, with about 60 meters of straight-section space available for accelerating structures. 8 refs

  12. Superconducting magnets for high energy storage rings

    International Nuclear Information System (INIS)

    Sampson, W.B.

    1977-01-01

    Superconducting dipole and quadrupole magnets were developed for the proton-proton intersecting storage accelerator ISABELLE. Full size prototypes of both kinds of magnets were constructed and successfully tested. The coils are fabricated from a single layer of wide braided superconductor and employ a low temperature iron core. This method of construction leads to two significant performance advantages; little or no training, and the ability of the coil to absorb its total magnetic stored energy without damage. A high pressure (15 atm) helium gas system is used for cooling. Measurements of the random field errors are compared with the expected field distribution. Three magnets (two dipoles and one quadrupole) were assembled into a segment of the accelerator ring structure (half cell). The performance of this magnet array, which is coupled in series both electrically and cryogenically, is also summarized

  13. Radiative polarization in high-energy storage rings

    International Nuclear Information System (INIS)

    Mane, S.R.

    1989-01-01

    Electron and positron beams circulating in high-energy storage rings become spontaneously polarized by the emission of synchrotron radiation. The asymptotic degree of polarization that can be attained is strongly affected by so-called depolarizing resonances. Detailed experimental measurements of the polarization were made SPEAR about ten years ago, but due to lack of a suitable theory only a limited theoretical fit to the data has so far been achieved. The author presents a general formalism for calculating depolarizing resonances, which has been coded into a computer program called SMILE, and use it to fit the SPEAR data. By the use of suitable approximations, the author is able to fit both higher order and nonlinear resonances, and thereby to interpret many hitherto unexplained features in the data, and to resolve a puzzle concerning the asymmetry of certain resonance widths seen in the data. 18 refs., 2 figs

  14. A zero-length bellows for the PEP-II High-Energy Ring

    International Nuclear Information System (INIS)

    Nordby, M.; Daly, E.F.; Kurita, N.; Langton, J.

    1995-08-01

    Due to the beamline space constrictions and the modular design of the vacuum system, a conventional bellows can not be used everywhere in the PEP-II High-Energy Ring (HER) arcs. A zero-length ''Flex Flange'' was developed which actually performs better than a more standard bellows. The Flex Flange fits the space available while still preserving the modularity of the system. Furthermore, the design provides for an accurate match-up between adjoining octagonal copper chambers despite the large fabrication and assembly tolerances and high operational loads. Beam chamber continuity is ensured by an integral RF seal ring which is easy to install and fault-tolerant. Heating from synchrotron radiation and higher-order mode trapping is managed to ensure a robust connection despite the 3,000 mA beam current of the PEP-II HER. The Flex Flange concept is versatile and adaptable to many applications, yet economical both in space needed and cost

  15. Development of an abort gap monitor for high-energy proton rings

    International Nuclear Information System (INIS)

    Beche, Jean-Francois; Byrd, John; De Santis, Stefano; Denes, Peter; Placidi, Massimo; Turner, William; Zolotorev, Max

    2004-01-01

    The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the ''abort gap'' and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitor based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider

  16. Development of an Abort Gap Monitor for High-Energy Proton Rings

    International Nuclear Information System (INIS)

    Beche, J.-F.; Byrd, J.; De Santis, S.; Denes, P.; Placidi, M.; Turner, W.; Zolotorev, M.

    2004-01-01

    The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the 'abort gap', and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitor based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider

  17. Vacuum system design for the PEP-II B Factory High-Energy Ring

    International Nuclear Information System (INIS)

    Perkins, C.; Bostic, D.; Daly, E.

    1994-06-01

    The design of the vacuum system for the PEP-II B Factory High-Energy Ring is reviewed. The thermal design and vacuum requirements are particularly challenging in PEP-II due to high stored beam currents up to 3.0 amps in 1658 bunches. The vacuum chambers for the HER arcs are fabricated by electron beam welding extruded copper sections up to 6 m long. Design of these chambers and the vacuum PumPing configuration is described with results from vacuum and thermal analyses

  18. Lifetimes of relativistic heavy-ion beams in the High Energy Storage Ring of FAIR

    Science.gov (United States)

    Shevelko, V. P.; Litvinov, Yu. A.; Stöhlker, Th.; Tolstikhina, I. Yu.

    2018-04-01

    The High Energy Storage Ring, HESR, will be constructed at the Facility for Antiproton and Ion Research, FAIR, Darmstadt. For the first time, it will be possible to perform experiments with cooled high-intensity stable and radioactive heavy ions at highly relativistic energies. To design experiments at the HESR, realistic estimations of beam lifetimes are indispensable. Here we report calculated cross sections and lifetimes for typical U88+ , U90+ , U92+ , Sn49+ and Sn50+ ions in the energy range E = 400 MeV/u-5 GeV/u, relevant for the HESR. Interactions with the residual gas and with internal gas-jet targets are also considered.

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

    International Nuclear Information System (INIS)

    Kapetanakos, C.A.

    1981-01-01

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

  20. Energy spectra of quantum rings.

    Science.gov (United States)

    Fuhrer, A; Lüscher, S; Ihn, T; Heinzel, T; Ensslin, K; Wegscheider, W; Bichler, M

    2001-10-25

    Quantum mechanical experiments in ring geometries have long fascinated physicists. Open rings connected to leads, for example, allow the observation of the Aharonov-Bohm effect, one of the best examples of quantum mechanical phase coherence. The phase coherence of electrons travelling through a quantum dot embedded in one arm of an open ring has also been demonstrated. The energy spectra of closed rings have only recently been studied by optical spectroscopy. The prediction that they allow persistent current has been explored in various experiments. Here we report magnetotransport experiments on closed rings in the Coulomb blockade regime. Our experiments show that a microscopic understanding of energy levels, so far limited to few-electron quantum dots, can be extended to a many-electron system. A semiclassical interpretation of our results indicates that electron motion in the rings is governed by regular rather than chaotic motion, an unexplored regime in many-electron quantum dots. This opens a way to experiments where even more complex structures can be investigated at a quantum mechanical level.

  1. Cooling equilibrium and beam loss with internal targets in high energy storage rings

    International Nuclear Information System (INIS)

    Boine-Frankenheim, O.; Hasse, R.; Hinterberger, F.; Lehrach, A.; Zenkevich, P.

    2006-01-01

    The beam cooling equilibrium with internal target interaction is analyzed for parameters relevant to the proposed High Energy Storage Ring (HESR). For the proposed experiments with anti-protons high luminosities together with low momentum spreads are required. Rate equations are used to predict the rms equilibrium beam parameters. The cooling and IBS rate coefficients are obtained from simplified models. Energy loss straggling in the target and the associated beam loss are analyzed analytically assuming a thin target. A longitudinal kinetic simulation code is used to study the evolution of the momentum distribution in coasting and bunched beams. Analytic expressions for the target induced momentum tail are found in good agreement with the simulation results

  2. An energy recovery electron linac-on-ring collider

    International Nuclear Information System (INIS)

    Merminga, L.; Krafft, G.A.; Lebedev, V.A.; Ben-Zvi, I.

    2000-01-01

    We present the design of high-luminosity electron-proton/ion colliders in which the electrons are produced by an Energy Recovering Linac (ERL). Electron-proton/ion colliders with center of mass energies between 14 GeV and 100 GeV (protons) or 63 GeV/A (ions) and luminosities at the 10 33 (per nucleon) level have been proposed recently as a means for studying hadronic structure. The linac-on-ring option presents significant advantages with respect to: (1) spin manipulations (2) reduction of the synchrotron radiation load in the detectors (3) a wide range of continuous energy variability. Rf power and beam dump considerations require that the electron linac recover the beam energy. Based on extrapolations from actual measurements and calculations, energy recovery is expected to be feasible at currents of a few hundred mA and multi-GeV energies. Luminosity projections for the linac-ring scenario based on fundamental limitations are presented. The feasibility of an energy recovery electron linac-on-proton ring collider is investigated and four conceptual point designs are shown corresponding to electron to proton energies of: 3 GeV on 15 GeV, 5 GeV on 50 GeV and 10 GeV on 250 GeV, and for gold ions with 100 GeV/A. The last two designs assume that the protons or ions are stored in the existing RHIC accelerator. Accelerator physics issues relevant to proton rings and energy recovery linacs are discussed and a list of required R and D for the realization of such a design is presented

  3. 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.)

  4. Photoswitchable Molecular Rings for Solar-Thermal Energy Storage.

    Science.gov (United States)

    Durgun, E; Grossman, Jeffrey C

    2013-03-21

    Solar-thermal fuels reversibly store solar energy in the chemical bonds of molecules by photoconversion, and can release this stored energy in the form of heat upon activation. Many conventional photoswichable molecules could be considered as solar thermal fuels, although they suffer from low energy density or short lifetime in the photoinduced high-energy metastable state, rendering their practical use unfeasible. We present a new approach to the design of chemistries for solar thermal fuel applications, wherein well-known photoswitchable molecules are connected by different linker agents to form molecular rings. This approach allows for a significant increase in both the amount of stored energy per molecule and the stability of the fuels. Our results suggest a range of possibilities for tuning the energy density and thermal stability as a function of the type of the photoswitchable molecule, the ring size, or the type of linkers.

  5. Strong-field physics using lasers and relativistic heavy ions at the high-energy storage ring HESR at FAIR

    International Nuclear Information System (INIS)

    Kuehl, T; Bagnoud, V; Stoehlker, T; Litvinov, Y; Winters, D F A; Zielbauer, B; Backe, H; Spielmann, Ch; Seres, J; Tünnermann, A; Neumayer, P; Aurand, B; Namba, S; Zhao, H Y

    2014-01-01

    The HESR high-energy ion storage ring at FAIR will provide unprecedented possibilities for strong-field physics using novel laser sources on relativistic heavy ions. An overview on the planning will be given.

  6. The vacuum system for the PEP II high energy ring straight sections

    International Nuclear Information System (INIS)

    Wienands, U.; Daly, E.; Heifets, S.A.; Kulikov, A.; Kurita, N.; Nordby, M.; Perkins, C.; Reuter, E.; Seeman, J.T.; Belser, F.C.; Berg, J.; Holdener, F.R.; Kerns, J.A.; McDaniel, M.R.; Stoeffl, W.

    1995-01-01

    The six straight sections of the PEP II High Energy Ring (HER) serve various functions: lattice tuning, beam injection and abort, providing space for rf cavities, longitudinal and transverse feedback, beam diagnostics and the interaction point. A stainless steel vacuum system has been designed; prototypes are currently being built. Cooling is required due to radiation coming from the last arc dipole and resistive losses in the vacuum chamber. Although the nominal beam current of the HER is 1 A the vacuum system is designed for 3 A to provide margin and an upgrade path. 5 refs., 7 figs

  7. Undulator tunability and synchrotron ring-energy

    International Nuclear Information System (INIS)

    Viccaro, P.J.; Sheony, G.K.

    1992-01-01

    An undulator has two properties which make it an extremely attractive source of electromagnetic radiation. The first is that the radiation is concentrated in a number of narrow energy bands known as harmonics of the device. The second characteristic is that under favorable operating conditions, the energy of these harmonics can be shifted or open-quote tunedclose quotes over an energy interval which can be as large as two or three times the value of the lowest energy harmonic. Both the photon energy of an undulator as well as its tunability are determined by the period, λ, of the device, the magnetic gap, G (which is larger than the minimum aperture required for injection and operation of the storage ring) and the storage ring energy E R . Given the photon energy, E p , the above parameters ultimately define the limits of operation or tunability of the undulator. In general, the larger the tunability range, the more useful the device. Therefore, for a given required maximum photon energy, it is desirable to find the operating conditions and device parameters which result in the largest tunability interval possible. With this in mind, we have investigated the question of undulator tunability with emphasis on the role of the ring energy in order to find the smallest E R consistent with the desired tunability interval and photon energy. As a guideline, we have included a preliminary criteria, concerning the tunability requirements for the Advanced Photon Source (APS) to be built at Argonne. The analysis is aimed at X-ray undulator sources on the APS but is applicable to any storage ring

  8. Proposal to detect an emission of unusual super-high energy electrons in electron storage rings

    Directory of Open Access Journals (Sweden)

    Da-peng Qian

    2014-01-01

    Full Text Available According to an extended Lorentz–Einstein mass formula taken into the uncertainty principle, it is predicted that the electron beams passing accelerating electric field should with a small probability generate abnormal super-high energy electrons which are much higher than the beam energy. Author’s preliminary experiment result at electron storage ring has hinted these signs, so suggests to more strictly detect this unusual phenomenon, and thus to test the extended mass formula as well as a more perfect special relativity.

  9. Status of the Frankfurt low energy electrostatic storage ring (FLSR)

    Science.gov (United States)

    King, F.; Kruppi, T.; Müller, J.; Dörner, R.; Schmidt, L. Ph H.; Schmidt-Böcking, H.; Stiebing, K. E.

    2015-11-01

    Frankfurt low-energy storage ring (FLSR) is an electrostatic storage ring for low-energy ions up to q · 80 keV (q being the ion charge state) at Institut für Kernphysik der Goethe-Universität, Frankfurt am Main, Germany. It has especially been designed to provide a basis for experiments on the dynamics of ionic and molecular collisions in complete kinematics, as well as for high precision and time resolved laser spectroscopy. The ring has ‘racetrack’ geometry with a circumference of 14.23 m. It comprises four experimental/diagnostic sections with regions of enhanced ion density (interaction regions). First beam has successfully been stored in FLSR in summer 2013. Since then the performance of the ring has continuously been improved and an electron target for experiments on dissociative recombination has been installed in one of the experimental sections.

  10. Analytic calculation of depolarization due to large energy spread in high-energy electron storage rings

    International Nuclear Information System (INIS)

    Buon, J.

    1989-08-01

    A new semiclassical and stochastic model of spin diffusion is used to obtain numerical predictions for depolarization enhancement due to beam energy spread. It confirms the results of previous models for the synchrotron sidebands of spin resonances. A satisfactory agreement is obtained with the width of a synchrotron satellite observed at SPEAR. For HERA, TRISTAN, and LEP at Z 0 energy, the depolarization enhancement is of the order of a few units and increases very rapidly with the energy spread. Large reduction of polarization degree is expected in these rings

  11. FLSR - The Frankfurt low energy storage ring

    International Nuclear Information System (INIS)

    Stiebing, K.E.; Alexandrov, V.; Doerner, R.; Enz, S.; Kazarinov, N.Yu.; Kruppi, T.; Schempp, A.; Schmidt Boecking, H.; Voelp, M.; Ziel, P.; Dworak, M.; Dilfer, W.

    2010-01-01

    An electrostatic storage ring for low-energy ions with a design energy of 50 keV is presently being set up at the Institut fuer Kernphysik der Johann Wolfgang Goethe-Universitaet Frankfurt am Main, Germany (IKF). This new device will provide a basis for new experiments on the dynamics of ionic and molecular collisions, as well as for high precision and time resolved laser spectroscopy. In this article, the design parameters of this instrument are reported.

  12. Status of the Frankfurt low energy electrostatic storage ring (FLSR)

    International Nuclear Information System (INIS)

    King, F; Kruppi, T; Müller, J; Dörner, R; Schmidt, L Ph H; Schmidt-Böcking, H; Stiebing, K E

    2015-01-01

    Frankfurt low-energy storage ring (FLSR) is an electrostatic storage ring for low-energy ions up to q · 80 keV (q being the ion charge state) at Institut für Kernphysik der Goethe-Universität, Frankfurt am Main, Germany. It has especially been designed to provide a basis for experiments on the dynamics of ionic and molecular collisions in complete kinematics, as well as for high precision and time resolved laser spectroscopy. The ring has ‘racetrack’ geometry with a circumference of 14.23 m. It comprises four experimental/diagnostic sections with regions of enhanced ion density (interaction regions). First beam has successfully been stored in FLSR in summer 2013. Since then the performance of the ring has continuously been improved and an electron target for experiments on dissociative recombination has been installed in one of the experimental sections. (paper)

  13. Lamb shift of energy levels in quantum rings

    International Nuclear Information System (INIS)

    Kryuchkyan, G Yu; Kyriienko, O; Shelykh, I A

    2015-01-01

    We study the vacuum radiative corrections to energy levels of a confined electron in quantum rings. The calculations are provided for the Lamb shift of energy levels in a low-momentum region of virtual photons and for both one-dimensional and two-dimensional quantum rings. We show that contrary to the well known case of a hydrogen atom the value of the Lamb shift increases with the magnetic momentum quantum number m. We also investigate the dependence of the Lamb shift on magnetic flux piercing the ring and demonstrate a presence of magnetic-flux-dependent oscillations. For a one-dimensional ring the value of the shift strongly depends on the radius of the ring. It is small for semiconductor rings but can attain measurable quantities in natural organic ring-shape molecules, such as benzene, cycloalcanes and porphyrins. (paper)

  14. Electron spin polarization in high-energy storage rings

    International Nuclear Information System (INIS)

    Mane, S.R.

    1987-01-01

    In a high energy storage ring, a single photon emission has relatively little effect on the orbital motion, but it can produce a relatively large change in the electron spin state. Hence the unperturbed orbital motion can be satisfactorily described using classical mechanics, but the spin must be treated quantum mechanically. The electron motion is therefore treated semi-classically in this thesis. It is explained how to diagonalize the unperturbed Hamiltonian to the leading order in Planck's constant. The effects of perturbations are then included, and the relevant time-scales and ensemble averages are elucidated. The Derbenev-Kondratenko formula for the equilibrium degree of polarization is rederived. Mathematical details of the rederivation are given. Since the original authors used a different formalism, a proof is offered of the equivalence between their method and the one used in this thesis. An algorithm is also presented to evaluate the equilibrium polarization. It has a number of new features, which enable the polarization to be calculated to a higher degree of approximation than has hitherto been possible. This facilitates the calculation of so-called spin resonances, which are points at which the polarization almost vanishes. A computer program has been written to implement the above algorithm, in the approximation of linear orbital dynamics, and sample results are presented

  15. FLSR - The Frankfurt low energy storage ring

    Science.gov (United States)

    Stiebing, K. E.; Alexandrov, V.; Dörner, R.; Enz, S.; Kazarinov, N. Yu.; Kruppi, T.; Schempp, A.; Schmidt Böcking, H.; Völp, M.; Ziel, P.; Dworak, M.; Dilfer, W.

    2010-02-01

    An electrostatic storage ring for low-energy ions with a design energy of 50 keV is presently being set up at the Institut für Kernphysik der Johann Wolfgang Goethe-Universität Frankfurt am Main, Germany (IKF). This new device will provide a basis for new experiments on the dynamics of ionic and molecular collisions, as well as for high precision and time resolved laser spectroscopy. In this article, the design parameters of this instrument are reported.

  16. Energy dependence of the emittance of damping ring beams

    International Nuclear Information System (INIS)

    Stiening, R.

    1985-01-01

    The energy at which the SLC damping rings are operated was chosen to be 1.21 GeV. At the time that that specification was made, the repetition rate of the SLC was expected to be 180 Hz. It is now anticipated that the repetition rate during the initial year of operation of the SLC will be 120 Hz. The following curves which show the output emittance of the damping rings as a function of input emittance and energy suggest that there is a range of energies over which the rings can be operated without changing the SLC luminosity. It should be noted that in the era of polarized beams, the damping ring energy will be fixed at the design value on account of the spin precession required in the LTR and RTL transport lines. The SLC design output emittance of the damping rings is 3 x 10 -5 radian-meters. Because of space charge disruption and quantum emission downstream of the damping rings, much lower values than the design value may not have a large beneficial effect on the luminosity. 3 figures

  17. Design and jump phenomenon analysis of an eccentric ring energy harvester

    International Nuclear Information System (INIS)

    Wang, Yu-Jen; Chen, Chung-De

    2013-01-01

    This paper presents the development of a wheel-mounted eccentric ring energy harvester that is driven by centripetal and gravitational forces during wheel rotation. The natural frequency of the eccentric ring matches the wheel rotation frequency at any car speed because its character length is designed equal to the wheel radius. Consequently, the eccentric ring oscillates with a relatively large swing angle at the wheel speed to generate high levels of power. The nonlinear dynamic behavior of the eccentric ring is investigated to ensure that the proposed design produces steady swing angles, especially at high wheel speeds. Herein, the jump phenomenon of the dynamic motion of the eccentric ring is analyzed by using the Duffing equation and the linearization process. The discriminant value obtained from the analysis confirms that no jump phenomenon occurs at all wheel speeds if the eccentric ring is properly designed. In the experiment, the eccentric ring is integrated with magnets and a coil set to generate 318–442 μW at constant wheel speeds between 300 and 500 rpm. This shows that the proposed device is a potential power source for low-power wheel-mounted electronics, such as pressure sensors, accelerometers, and thermometers. (paper)

  18. Design and jump phenomenon analysis of an eccentric ring energy harvester

    Science.gov (United States)

    Wang, Yu-Jen; Chen, Chung-De

    2013-10-01

    This paper presents the development of a wheel-mounted eccentric ring energy harvester that is driven by centripetal and gravitational forces during wheel rotation. The natural frequency of the eccentric ring matches the wheel rotation frequency at any car speed because its character length is designed equal to the wheel radius. Consequently, the eccentric ring oscillates with a relatively large swing angle at the wheel speed to generate high levels of power. The nonlinear dynamic behavior of the eccentric ring is investigated to ensure that the proposed design produces steady swing angles, especially at high wheel speeds. Herein, the jump phenomenon of the dynamic motion of the eccentric ring is analyzed by using the Duffing equation and the linearization process. The discriminant value obtained from the analysis confirms that no jump phenomenon occurs at all wheel speeds if the eccentric ring is properly designed. In the experiment, the eccentric ring is integrated with magnets and a coil set to generate 318-442 μW at constant wheel speeds between 300 and 500 rpm. This shows that the proposed device is a potential power source for low-power wheel-mounted electronics, such as pressure sensors, accelerometers, and thermometers.

  19. A Monte-Carlo simulation of the equilibrium beam polarization in ultra-high energy electron (positron) storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Zhe, E-mail: zhe.duan@ihep.ac.cn [Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing (China); University of Chinese Academy of Sciences, 100049 Beijing (China); Bai, Mei [Forschungszentrum Jülich GmbH, 52428 Jülich (Germany); Barber, Desmond P. [Deutsches Elektronen-Synchrotron, DESY, 22607 Hamburg (Germany); Qin, Qing [Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing (China)

    2015-09-01

    With the recently emerging global interest in building a next generation of circular electron–positron colliders to study the properties of the Higgs boson, and other important topics in particle physics at ultra-high beam energies, it is also important to pursue the possibility of implementing polarized beams at this energy scale. It is therefore necessary to set up simulation tools to evaluate the beam polarization at these ultra-high beam energies. In this paper, a Monte-Carlo simulation of the equilibrium beam polarization based on the Polymorphic Tracking Code (PTC) (Schmidt et al., 2002 [1]) is described. The simulations are for a model storage ring with parameters similar to those of proposed circular colliders in this energy range, and they are compared with the suggestion (Derbenev et al., 1979 [2]) that there are different regimes for the spin dynamics underlying the polarization of a beam in the presence of synchrotron radiation at ultra-high beam energies. In particular, it has been suggested that the so-called “correlated” crossing of spin resonances during synchrotron oscillations at current energies evolves into “uncorrelated” crossing of spin resonances at ultra-high energies.

  20. A Monte-Carlo simulation of the equilibrium beam polarization in ultra-high energy electron (positron) storage rings

    International Nuclear Information System (INIS)

    Duan, Zhe; Bai, Mei; Barber, Desmond P.; Qin, Qing

    2015-04-01

    With the recently emerging global interest in building a next generation of circular electron-positron colliders to study the properties of the Higgs boson, and other important topics in particle physics at ultra-high beam energies, it is also important to pursue the possibility of implementing polarized beams at this energy scale. It is therefore necessary to set up simulation tools to evaluate the beam polarization at these ultra-high beam energies. In this paper, a Monte-Carlo simulation of the equilibrium beam polarization based on the Polymorphic Tracking Code(PTC) (Schmidt et al., 2002) is described. The simulations are for a model storage ring with parameters similar to those of proposed circular colliders in this energy range, and they are compared with the suggestion (Derbenev et al., 1978) that there are different regimes for the spin dynamics underlying the polarization of a beam in the presence of synchrotron radiation at ultra-high beam energies. In particular, it has been suggested that the so-called ''correlated'' crossing of spin resonances during synchrotron oscillations at current energies, evolves into ''uncorrelated'' crossing of spin resonances at ultra-high energies.

  1. Future of high energy physics

    International Nuclear Information System (INIS)

    Panofsky, W.K.H.

    1984-06-01

    A rough overview is given of the expectations for the extension of high energy colliders and accelerators into the xtremely high energy range. It appears likely that the SSC or something like it will be the last gasp of the conventional method of producing high energy proton-proton collisions using synchrotron rings with superconducting magnets. It is likely that LEP will be the highest energy e+e - colliding beam storage ring built. The future beyond that depends on the successful demonstrations of new technologies. The linear collider offers hope in this respect for some extension in energy for electrons, and maybe even for protons, but is too early to judge whether, by how much, or when such an extension will indeed take place

  2. Theoretical aspects of some collective instabilities in high-energy particle storage rings

    International Nuclear Information System (INIS)

    Ruggiero, F.

    1986-01-01

    After an introduction to single-particle dynamics, based on a unified Hamiltonian treatment of betatron and synchrotron oscillations, we consider two examples of collective instabilities which can limit the performances of high-energy storage rings: the transverse mode coupling instability, due to wake fields, and the incoherent beam-beam instability. Special emphasis is placed on the localization of the interactions between particles and surrounding structures, such as the accelerating RF cavities. We derive an exact invariant for the linearized synchrotron motion and, starting from the Vlasov equation, we discuss the coherent synchro-betatron resonances caused by localized impedance. Under suitable assumptions, we show that the effect of the beam-beam kicks in electron-positron machines can be described by new diffusive terms in a ''renormalized'' Fokker-Planck equation and is therefore equivalent to an additional source of noise for the betatron oscillations. (orig.)

  3. D{sup -} energy spectrum in toroidal quantum ring

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, C A; Gutierrez, W; Garcia, L F [Universidad Industrial de Santander, Bucaramanga (Colombia); Marin, J H, E-mail: jhmarin@unal.edu.c [Universidad Nacional-Colombia, Medellin-Colombia, AA3840 (Colombia)

    2009-05-01

    The structure of energy spectrum of the negative donor centre in a toroidal-shaped quantum ring with two different morphologies of the cross-section is analyzed. By using the adiabatic procedure we have deduced a one-dimensional wave equation with periodic conditions which describes the low-lying energy levels related to the electrons rotation around the symmetry axis. Our results are in good agreement with those previously obtained as the size of the ring cross-section tends to zero.

  4. Ultra-low energy storage ring at FLAIR

    International Nuclear Information System (INIS)

    Welsch, Carsten P.; Papash, A. I.; Gorda, O.; Harasimowicz, J.; Karamyshev, O.; Karamysheva, G.; Newton, D.; Panniello, M.; Putignano, M.; Siggel-King, M. R. F.; Smirnov, A.

    2012-01-01

    The Ultra-low energy electrostatic Storage Ring (USR) at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) will provide cooled beams of antiprotons in the energy range between 300 keV down to 20 keV and possibly less. The USR has been completely redesigned over the past three years. The ring structure is based on a “split achromat” lattice that allows in-ring experiments with internal gas jet target. Beam parameters might be adjusted in a wide range: from very short pulses in the nanosecond regime to a Coasting beam. In addition, a combined fast and slow extraction scheme was developed that allows for providing external experiments with cooled beams of different time structure. Detailed investigations of the USR, including studies into the ring’s long term beam dynamics, life time, equilibrium momentum spread and equilibrium lateral spread during collisions with an internal target were carried out. New tools and beam handling techniques for diagnostics of ultra-low energy ions at beam intensities less than 10 6 were developed by the QUASAR Group. In this paper, progress on the USR project will be presented with an emphasis on the expected beam parameters available to the experiments at FLAIR.

  5. CHESS-the Cornell High Energy Synchrotron Source

    International Nuclear Information System (INIS)

    Batterman, B.W.; Cornell Univ., Ithaca, NY

    1980-01-01

    The Wilson Laboratory at Cornell University has done pioneering work on development of high energy synchrotrons. In the last decade, the 12 GeV synchrotron has been the most energetic electron synchrotron in the world. In 1975 plans were formulated to build a 4-8 GeV storage ring in the same tunnel as the synchrotron and to use the latter as the injector for the storage ring. This small radius (the normal bend magnets have R = 87 m), coupled with the relatively high electron energy of the storage ring, makes these magnets potent sources of synchrotron radiation. In June of 1978 the National Science Foundation funded a project to create CHESS, the Cornell High Energy Synchrotron Source. (orig./FKS)

  6. Carbon filament beam profile monitor for high energy proton-antiproton storage rings

    International Nuclear Information System (INIS)

    Evans, L.R.; Shafer, R.E.

    1979-01-01

    The measurement of the evolution of the transverse profile of the stored beams in high energy proton storage rings such as the p-anti p colliders at CERN and at FNAL is of considerable importance. In the present note, a simple monitor is discussed which will allow almost non-destructive measurement of the profile of each individual proton and antiproton bunch separately. It is based on the flying wire technique first used at CEA and more recently at the CPS. A fine carbon filament is passed quickly through the beam, acting as a target for secondary particle production. The flux of secondary particles is measured by two scintillator telescopes, one for protons and one for antiprotons, having an angular acceptance between 30 and 100 mrad. Measurements of secondary particle production performed at FNAL in this angular range show that a very respectable flux can be expected

  7. Performance of high-resolution position-sensitive detectors developed for storage-ring decay experiments

    International Nuclear Information System (INIS)

    Yamaguchi, T.; Suzaki, F.; Izumikawa, T.; Miyazawa, S.; Morimoto, K.; Suzuki, T.; Tokanai, F.; Furuki, H.; Ichihashi, N.; Ichikawa, C.; Kitagawa, A.; Kuboki, T.; Momota, S.; Nagae, D.; Nagashima, M.; Nakamura, Y.; Nishikiori, R.; Niwa, T.; Ohtsubo, T.; Ozawa, A.

    2013-01-01

    Highlights: • Position-sensitive detectors were developed for storage-ring decay spectroscopy. • Fiber scintillation and silicon strip detectors were tested with heavy ion beams. • A new fiber scintillation detector showed an excellent position resolution. • Position and energy detection by silicon strip detectors enable full identification. -- Abstract: As next generation spectroscopic tools, heavy-ion cooler storage rings will be a unique application of highly charged RI beam experiments. Decay spectroscopy of highly charged rare isotopes provides us important information relevant to the stellar conditions, such as for the s- and r-process nucleosynthesis. In-ring decay products of highly charged RI will be momentum-analyzed and reach a position-sensitive detector set-up located outside of the storage orbit. To realize such in-ring decay experiments, we have developed and tested two types of high-resolution position-sensitive detectors: silicon strips and scintillating fibers. The beam test experiments resulted in excellent position resolutions for both detectors, which will be available for future storage-ring experiments

  8. Small electrostatic storage rings; also for highly charged ions?

    International Nuclear Information System (INIS)

    Moeller, S.P.; Pedersen, U.V.

    2001-01-01

    Two years ago, a small electrostatic storage ring ELISA (electrostatic ion storage ring, Aarhus) was put into operation. The design of this small 7 m circumference ring was based on electrostatic deflection plates and quadrupoles. This is in contrast to the larger ion storage rings, which are based on magnetic focusing and deflection. The result is a small, relatively inexpensive, storage ring being able to store ions of any mass and any charge at low energy ( -11 mbar resulting in storage times of several tens of seconds for singly charged ions. The maximum number of singly charged ions that can be stored is a few 10 7 . Several experiments have already been performed in ELISA. These include lifetime studies of metastable ions and studies of fullerenes and metal-cluster ions. Lasers are also used for excitation of the circulating ions. Heating/cooling of the ring is possible. Cooling of the ring leads to significantly lower pressures, and correspondingly longer lifetimes. A change of the temperature of the vacuum chambers surrounding the ion beam also leads to a change of the spectrum of the black-body radiation, which has a significant influence on weakly bound negative ions. At the time of writing, at least two other electrostatic storage rings are being built, and more are planned. In the following, the electrostatic storage ring ELISA will be described, and results from some of the initial experiments demonstrating the performance will be shown. The relative merits of such a ring, as opposed to the larger magnetic rings and the smaller ion traps will be discussed. The potential for highly charged ions will be briefly mentioned. (orig.)

  9. Results and analysis of free-electron-laser oscillation in a high-energy storage ring

    International Nuclear Information System (INIS)

    Couprie, M.E.; Velghe, M.; Prazeres, R.; Jaroszynski, D.; Billardon, M.

    1991-01-01

    A storage-ring free-electron laser at Orsay has been operating since 1989 in the visible wavelength range. In contrast with previous experiments, it operates with positrons and at higher energies (600--800 MeV), with the storage ring Super-ACO (ACO denotes Anneau de Collisions d'Orsay). The optical gain, the laser power, the transverse profile, and the macrotemporal structure of the laser are analyzed. In particular, we show that the gain matrix possesses many off-diagonal elements, which results in lasing on a combination of noncylindrical Gaussian modes. The eigenmode of the laser oscillation is a combination of one or two main Gaussian modes and several higher-order modes, which results in most of the power being extracted in these modes

  10. Energy transfer between a passing vortex ring and a flexible plate in an ideal quiescent fluid

    Energy Technology Data Exchange (ETDEWEB)

    Hu, JiaCheng; Peterson, Sean D., E-mail: peterson@mme.uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Porfiri, Maurizio [Department of Mechanical and Aerospace Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201 (United States)

    2015-09-21

    Recent advancements in highly deformable smart materials have lead to increasing interest in small-scale energy harvesting research for powering low consumption electronic devices. One such recent experimental study by Goushcha et al. explored energy harvesting from a passing vortex ring by a cantilevered smart material plate oriented parallel to and offset from the path of the ring in an otherwise quiescent fluid. The present study focuses on modeling this experimental study using potential flow to facilitate optimization of the energy extraction from the passing ring to raise the energy harvesting potential of the device. The problem is modeled in two-dimensions with the vortex ring represented as a pair of counter-rotating free vortices. Vortex pair parameters are determined to match the convection speed of the ring in the experiments, as well as the imposed pressure loading on the plate. The plate is approximated as a Kirchhoff-Love plate and represented as a finite length vortex sheet in the fluid domain. The analytical model matches experimental measurements, including the tip displacement, the integrated force along the entire plate length as a function of vortex ring position, and the pressure along the plate. The potential flow solution is employed in a parametric study of the governing dimensionless parameters in an effort to guide the selection of plate properties for optimal energy harvesting performance. Results of the study indicate an optimal set of plate properties for a given vortex ring configuration, in which the time-scale of vortex advection matches that of the plate vibration.

  11. Electron cooling of PB$^{54+}$ ions in the low energy ion ring (LEIR)

    CERN Document Server

    Bosser, Jacques; Chanel, M; MacCaferri, R; Maury, S; Möhl, D; Molinari, G; Tranquille, G

    1998-01-01

    For the preparation of dense bunches of lead ions for the LHC, electron cooling will be essential for accumula tion in a storage ring at 4.2 MeV/u. Tests have been carried out on the LEAR ring (renamed LEIR for Low Energy Ion Ring) in order to determine the optimum parameters for a future state-of-the-art electron cooling device which would be able to cool linac pulses of lead ions in less than 100 ms. The experiments focused on the generation of a stable high intensity electron beam that is needed to free space in both longitudinal and transverse phase space for incoming pulses. Investigations on the ion beam lifetime in the presence of the electron beam and on the dependency of the cooling times on the optical settings of the storage ring will also be discussed. This paper concentrates on the cooling aspects with the multiturn injection, vacuum, and high intensity aspects discussed in a companion paper at this conference.

  12. The PEP-II Project: Low-Energy Ring Design and Project Status

    International Nuclear Information System (INIS)

    Zisman, Michael S.

    2006-01-01

    We describe the present status of the PEP-II project. The project comprises four major systems: Injector, High-Energy Ring (HER), Low-Energy Ring (LER), and Interaction Region (IR). We focus in detail on the design of the LER, as its parameters and requirements are most closely related to those required for the Beijing Tau-Charm Factory rings. The PEP-II LER is a high-current, 3.1-GeV positron ring mounted above the 9-GeV HER. The LER uses a wiggler located in one of its six straight sections to provide emittance control and additional damping. We describe the rather complicated IR, which must transport the LER beam into the plane of the HER, focus it to a common beam size, and separate the beams after the head-on collisions. Both permanent magnet and conventional electromagnets are used in this area. The LER lattice has now adopted a simplified non-interleaved sextupole correction scheme that has reduced the required number of sextupoles substantially. We describe the LER vacuum system, one of the most challenging subsystems in PEP-II. It employs several technologies. In the arcs, aluminum extrusions and titanium sublimation pumps are employed; the straight sections use stainless steel chambers with lumped ion pumps. In the wiggler area, an extended copper photon dump with nonevaporable getter (NEG) pumps is employed to handle the very large synchrotron radiation power. The design of the room-temperature RF system, the bunch-by-bunch longitudinal and transverse feedback systems, and some of the special diagnostics will be described briefly. The PEP-II project remains on schedule to begin commissioning of the HER in April 1997, followed by the LER a year later

  13. The evolution of ring current ion energy density and energy content during geomagnetic storms based on Van Allen Probes measurements

    International Nuclear Information System (INIS)

    Zhao, H.; University of Colorado, Boulder, CO; Li, X.; University of Colorado, Boulder, CO; Baker, D. N.

    2015-01-01

    Enabled by the comprehensive measurements from the Magnetic Electron Ion Spectrometer (MagEIS), Helium Oxygen Proton Electron mass spectrometer (HOPE), and Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instruments onboard Van Allen Probes in the heart of the radiation belt, the relative contributions of ions with different energies and species to the ring current energy density and their dependence on the phases of geomagnetic storms are quantified. The results show that lower energy (<50 keV) protons enhance much more often and also decay much faster than higher-energy protons. During the storm main phase, ions with energies <50 keV contribute more significantly to the ring current than those with higher energies; while the higher-energy protons dominate during the recovery phase and quiet times. The enhancements of higher-energy proton fluxes as well as energy content generally occur later than those of lower energy protons, which could be due to the inward radial diffusion. For the 29 March 2013 storm we investigated in detail that the contribution from O + is ~25% of the ring current energy content during the main phase and the majority of that comes from <50 keV O + . This indicates that even during moderate geomagnetic storms the ionosphere is still an important contributor to the ring current ions. Using the Dessler-Parker-Sckopke relation, the contributions of ring current particles to the magnetic field depression during this geomagnetic storm are also calculated. In conclusion, the results show that the measured ring current ions contribute about half of the Dst depression.

  14. A Low-Energy Ring Lattice Design

    International Nuclear Information System (INIS)

    Cai, Yunhai

    2002-01-01

    The PEP-N project at SLAC [1] consists of a Very Low-Energy small electron Ring (VLER) that will collide with the low-energy 3.1 GeV positron beam (LER) of PEP-II, producing center-of-mass energies between the 1.1 GeV and the J/ψ. The beams will collide head-on and will be separated in the detector magnetic field which is part of the Interaction Region [2]. The IP β functions were chosen such as to optimize both luminosity and beam-beam tune shifts, while keeping the LER tune shifts small. This paper describes the lattice design of the VLER for the ''baseline'' at 500 MeV

  15. Superposed Redox Chemistry of Fused Carbon Rings in Cyclooctatetraene-Based Organic Molecules for High-Voltage and High-Capacity Cathodes.

    Science.gov (United States)

    Zhao, Xiaolin; Qiu, Wujie; Ma, Chao; Zhao, Yingqin; Wang, Kaixue; Zhang, Wenqing; Kang, Litao; Liu, Jianjun

    2018-01-24

    Even though many organic cathodes have been developed and have made a significant improvement in energy density and reversibility, some organic materials always generate relatively low voltage and limited discharge capacity because their energy storage mechanism is solely based on redox reactions of limited functional groups [N-O, C═X (X = O, N, S)] linking to aromatic rings. Here, a series of cyclooctatetraene-based (C 8 H 8 ) organic molecules were demonstrated to have electrochemical activity of high-capacity and high-voltage from carbon rings by means of first-principles calculations and electronic structure analysis. Fused molecules of C 8 -C 4 -C 8 (C 16 H 12 ) and C 8 -C 4 -C 8 -C 4 -C 8 (C 24 H 16 ) contain, respectively, four and eight electron-deficient carbons, generating high-capacity by their multiple redox reactions. Our sodiation calculations predict that C 16 H 12 and C 24 H 16 exhibit discharge capacities of 525.3 and 357.2 mA h g -1 at the voltage change from 3.5 to 1.0 V and 3.7 to 1.3 V versus Na + /Na, respectively. Electronic structure analysis reveals that the high voltages are attributed to superposed electron stabilization mechanisms, including double-bond reformation and aromatization from carbon rings. High thermodynamic stability of these C 24 H 16 -based systems strongly suggests feasibility of experimental realization. The present work provides evidence that cyclooctatetraene-based organic molecules fused with the C 4 ring are promising in designing high-capacity and high-voltage organic rechargeable cathodes.

  16. Application of FEL technique for constructing high-intensity, monochromatic, polarized gamma-sources at storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

    1995-12-31

    A possibility to construct high-intensity tunable monochromatic{gamma}-source at high energy storage rings is discussed. It is proposed to produce {gamma}-quanta by means of Compton backscattering of laser photons on electrons circulating in the storage. The laser light wavelength is chosen in such a way that after the scattering, the electron does not leave the separatrix. So as the probability of the scattering is rather small, energy oscillations are damped prior the next scattering. As a result, the proposed source can operate in {open_quotes}parasitic{close_quote} mode not interfering with the main mode of the storage ring operation. Analysis of parameters of existent storage rings (PETRA, ESRF, Spring-8, etc) shows that the laser light wavelength should be in infrared, {lambda}{approximately} 10 - 400 {mu}m, wavelength band. Installation at storage rings of tunable free-electron lasers with the peak and average output power {approximately} 10 MW and {approximately} 1 kW, respectively, will result in the intensity of the {gamma}-source up to {approximately} 10{sup 14}s{sup -1} with tunable {gamma}-quanta energy from several MeV up to several hundreds MeV. Such a {gamma}-source will reveal unique possibilities for precision investigations in nuclear physics.

  17. LASL high-current proton storage rings

    International Nuclear Information System (INIS)

    Lawrence, G.P.; Cooper, R.K.; Hudgings, D.W.; Spalek, G.; Jason, A.J.; Higgins, E.F.; Gillis, R.E.

    1980-01-01

    The Proton Storage Ring at LAMPF is a high-current accumulator designed to convert long 800-MeV linac pulses into very short high-intensity proton bunches ideally suited to driving a pulsed polyenergetic neutron source. The Ring, authorized for construction at $19 million, will operate in a short-bunch high-frequency mode for fast neutron physics and a long-bunch low-frequency mode for thermal neutron-scattering programs. Unique features of the project include charge-changing injection with initial conversion from H - to H 0 , a high repetition rate fast-risetime extraction kicker, and high-frequency and first-harmonic bunching system

  18. Beam dynamics issues of high-luminosity asymmetric collider rings

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1990-01-01

    Machines for use in high-energy physics are advancing along two frontiers. First, there is the frontier of energy, currently being pressed by the Fermilab collider (p bar p), and SLC and LEP (e + e - ) and in the near future by HERA (ep), the LHC, and the SSC (pp). Second, there is the frontier of intensity, currently being pressed by a variety of low-energy machines and, at higher energies, by various linacs such as those at KEK. Fermilab, GSI, and LAMPF (p) and CEBAF (e - ). In the future there should be, along this frontier, various ''factories'' such as those for Kaons at TRIUMF, and those proposed for var-phi mesons, τ-charm particles, and B mesons. It is with the intensity frontier that these proceedings are concerned. The elementary particle motivation to study the nonconservation of PC in the B-stringB system (which topic is not covered in these Proceedings, but is treated extensively in the literature) has motivated the study of very high intensity asymmetric collider rings. It was for this purpose that a Workshop on Beam Dynamics Issues of High-Luminosity Asymmetric Collider Rings was held, in Berkeley, during February 12--16, 1990. A general introduction to the subject has been given in an article which is reprinted here as an Appendix. The nonexpert may wish to start there. The volume consists of four parts. The first part consists of Summaries; first an overall summary of the Workshop and then, second, more detailed summaries from each of the working groups. The second part consists of the Invited Talks at the workshop. The third part contains various Contributed Papers, most of which represent work that came out of the workshop. Finally, there are, in the fourth part, brief Summaries of the Various Proposed B-Factory Projects in the world

  19. Storage Rings

    International Nuclear Information System (INIS)

    Fischer, W.

    2010-01-01

    Storage rings are circular machines that store particle beams at a constant energy. Beams are stored in rings without acceleration for a number of reasons (Tab. 1). Storage rings are used in high-energy, nuclear, atomic, and molecular physics, as well as for experiments in chemistry, material and life sciences. Parameters for storage rings such as particle species, energy, beam intensity, beam size, and store time vary widely depending on the application. The beam must be injected into a storage ring but may not be extracted (Fig. 1). Accelerator rings such as synchrotrons are used as storage rings before and after acceleration. Particles stored in rings include electrons and positrons; muons; protons and anti-protons; neutrons; light and heavy, positive and negative, atomic ions of various charge states; molecular and cluster ions, and neutral polar molecules. Spin polarized beams of electrons, positrons, and protons were stored. The kinetic energy of the stored particles ranges from 10 -6 eV to 3.5 x 10 12 eV (LHC, 7 x 10 12 eV planned), the number of stored particles from one (ESR) to 1015 (ISR). To store beam in rings requires bending (dipoles) and transverse focusing (quadrupoles). Higher order multipoles are used to correct chromatic aberrations, to suppress instabilities, and to compensate for nonlinear field errors of dipoles and quadrupoles. Magnetic multipole functions can be combined in magnets. Beams are stored bunched with radio frequency systems, and unbunched. The magnetic lattice and radio frequency system are designed to ensure the stability of transverse and longitudinal motion. New technologies allow for better storage rings. With strong focusing the beam pipe dimensions became much smaller than previously possible. For a given circumference superconducting magnets make higher energies possible, and superconducting radio frequency systems allow for efficient replenishment of synchrotron radiation losses of large current electron or positron beams

  20. Approximate calculation of electronic energy levels of axially symmetric quantum dot and quantum ring by using energy dependent effective mass

    International Nuclear Information System (INIS)

    Yu-Min, Liu; Zhong-Yuan, Yu; Xiao-Min, Ren

    2009-01-01

    Calculations of electronic structures about the semiconductor quantum dot and the semiconductor quantum ring are presented in this paper. To reduce the calculation costs, for the quantum dot and the quantum ring, their simplified axially symmetric shapes are utilized in our analysis. The energy dependent effective mass is taken into account in solving the Schrödinger equations in the single band effective mass approximation. The calculated results show that the energy dependent effective mass should be considered only for relatively small volume quantum dots or small quantum rings. For large size quantum materials, both the energy dependent effective mass and the parabolic effective mass can give the same results. The energy states and the effective masses of the quantum dot and the quantum ring as a function of geometric parameters are also discussed in detail. (general)

  1. Design of low energy ring(s)

    CERN Document Server

    Lachaize, Antoine

    During the last two years, several upgrades of the initial baseline scenario were studied with the aim of increasing the average intensity of ion beams in the accelerator chain of the Beta Beam complex. This is the reason why the Rapid Cycling Synchrotron (RCS) specifications were reconsidered many times [1], [2], [3].General considerations on the optical design were presented at the Beta Beam Task Meetings held at CERN and at Saclay in 2005 [4]. More detailed beam optics studies were performed during the next months. Lattices, RF system parameters, multi-turn injection scheme, fast extraction, closed orbit correction and chromaticity correction systems were proposed for different versions of the RCS [5], [6], [7].Finally, the RCS specifications have stabilized in November 2006 after the fourth Beta Beam Task Meeting when it was decided to fix the maximum magnetic rigidity of ion beams to 14.47 T.m (3.5 GeV equivalent proton energy) and to adopt a ring physical radius of 40 m in order to facilitate injectio...

  2. Optimum Energy Extraction from Coherent Vortex Rings Passing Tangentially Over Flexible Plates

    Science.gov (United States)

    Pirnia, Alireza; Browning, Emily A.; Peterson, Sean D.; Erath, Byron D.

    2017-11-01

    Coherent vortical structures can incite self-sustained oscillations in flexible membranes. This concept has recently gained interest for energy extraction from ambient environments. In this study the special case of a vortex ring passing tangentially over a cantilevered flexible plate is investigated. This problem is governed by the Kirchhoff-Love plate equation, which can be expressed in terms of a non-dimensional mass parameter of the plate, non-dimensional pressure loading induced by the vortex ring, and a Strouhal (St) number which expresses the duration of pressure loading relative to the period of plate oscillation. For a plate with a fixed mass parameter immersed in a fluid environment, the St number specifies the beam dynamics and the energy exchange process. The aim of this study is to identify the St number corresponding to maximum energy exchange between plates and vortex rings. The energy exchange process between the vortex ring and the plate is investigated over a range of 0.3 transfer is reported in each case and an empirical correlation is provided for predictive purposes. Supported by the National Science Foundation (NSF) under Grant No. CBET-1511761, and the Natural Sciences and Engineering Research Council of Canada (NSERC), under Grant No. 05778-2015.

  3. Acceleration of magnetized plasma rings

    International Nuclear Information System (INIS)

    Hartman, D.; Eddleman, J.; Hammer, J.H.

    1982-01-01

    One scheme is considered, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focussing) during acceleration. Because the allowable acceleration force F/sub a/ = kappa U/sub m//R (kappa - 2 , the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency

  4. Interaction Region Design for a Ring-Ring LHeC

    CERN Document Server

    Thompson, L N S; Bernard, N R; Fitterer, M; Holzer, B; Klein, M; Kostka, P

    2011-01-01

    tively low energy and moderately high intensity provides high luminosity TeV-scale e-p collisions at one of the LHC interaction points, running simultaneously with existing experiments. Two designs are studied; an electron ring situated in the LHC tunnel, and an electron linac. The focus of this paper is on the ring design. Designing an e-p machine presents interesting accelerator physics and design challenges, particularly when considering the interaction region. These include coupled optics, beam separation and unconventional mini-beta focusing schemes. Designs are constrained by an array of interdependent factors, including beam-beam interaction, detector dimensions and acceptance, luminosity and synchrotron radiation. Methods of addressing these complex issues are discussed. The current designs for the LHeC Ring-Ring interaction region and long straight section are presented and discussed, in the context of the project goals and design challenges encountered. Future developments and work are also discusse...

  5. Electron beam cooling at a magnetic storage ring, TARN II, and an electrostatic storage ring

    International Nuclear Information System (INIS)

    Tanabe, Tetsumi

    2006-01-01

    At the High Energy Accelerator Research Organization (KEK), a magnetic storage ring, TARN II, with an electron cooler was operated from 1989 to 1999, while an electrostatic storage ring with a small electron cooler has been operational since 2000. In this paper, the electron cooling at TARN II and the electrostatic storage ring is described. (author)

  6. Suppressing the Coffee-Ring Effect in Semitransparent MnO2 Film for a High-Performance Solar-Powered Energy Storage Window.

    Science.gov (United States)

    Jin, Huanyu; Qian, Jiasheng; Zhou, Limin; Yuan, Jikang; Huang, Haitao; Wang, Yu; Tang, Wing Man; Chan, Helen Lai Wa

    2016-04-13

    We introduce a simple and effective method to deposit a highly uniform and semitransparent MnO2 film without coffee-ring effect (CRE) by adding ethanol into MnO2 ink for transparent capacitive energy storage devices. By carefully controlling the amount of ethanol added in the MnO2 droplet, we could significantly reduce the CRE and thus improve the film uniformity. The electrochemical properties of supercapacitor (SC) devices using semitransparent MnO2 film electrodes with or without CRE were measured and compared. The SC device without CRE shows a superior capacitance, high rate capability, and lower contact resistance. The CRE-free device could achieve a considerable volumetric capacitance of 112.2 F cm(-3), resulting in a high volumetric energy density and power density of 10 mWh cm(-3) and 8.6 W cm(-3), respectively. For practical consideration, both flexible SC and large-area rigid SC devices were fabricated to demonstrate their potential for flexible transparent electronic application and capacitive energy-storage window application. Moreover, a solar-powered energy storage window which consists of a commercial solar cell and our studied semitransparent MnO2-film-based SCs was assembled. These SCs could be charged by the solar cell and light up a light emitting diode (LED), demonstrating their potential for self-powered systems and energy-efficient buildings.

  7. High energy polarized electron beams

    International Nuclear Information System (INIS)

    Rossmanith, R.

    1987-01-01

    In nearly all high energy electron storage rings the effect of beam polarization by synchrotron radiation has been measured. The buildup time for polarization in storage rings is of the order of 10 6 to 10 7 revolutions; the spins must remain aligned over this time in order to avoid depolarization. Even extremely small spin deviations per revolution can add up and cause depolarization. The injection and the acceleration of polarized electrons in linacs is much easier. Although some improvements are still necessary, reliable polarized electron sources with sufficiently high intensity and polarization are available. With the linac-type machines SLC at Stanford and CEBAF in Virginia, experiments with polarized electrons will be possible

  8. Injection, compression and stability of intense ion-rings

    International Nuclear Information System (INIS)

    Sudan, R.N.

    1975-01-01

    Recent advances in pulsed high power ion beam technology make possible the creation of intense ion-rings with strong self-magnetic fields by single pulse injection. Such ion rings have several uses in controlled fusion e.g., to produce a min parallel B parallel magnetic geometry with a mirror ratio much higher than is possible with external conductors. For even stronger ion rings a min parallel B parallel with closed lines of force (ASTRON type) can be created. For this purpose, since the ion energies required are much higher than are available from high power sources, magnetic compression can be utilized to increase the ion energy. The success of this scheme depends critically on the stability of the ion ring. The low frequency perturbations of the ring-plasma system is examined by means of a generalization of the energy principle which established sufficient conditions for stability. The high-frequency micro-instabilities and their nonlinear consequences are discussed in terms of conventional techniques

  9. Superconducting magnets in high energy physics

    International Nuclear Information System (INIS)

    Prodell, A.G.

    1978-01-01

    The applications of superconducting magnets in high energy physics in the last ten years have made feasible developments which are vital to high energy research. These developments include high magnetic field, large volume detectors, such as bubble chambers, required for effective resolution of high energy particle trajectories, particle beam transport magnets, and superconducting focusing and bending magnets for the very high energy accelerators and storage rings needed to pursue the study of interactions between elementary particles. The acceptance of superconductivity as a proven technology in high energy physics was reinforced by the recognition that the existing large accelerators using copper-iron magnets had reached practical limits in terms of magnetic field intensity, cost, space, and energy usage, and that large-volume, high-field, copper-iron magnets were not economically feasible. Some of the superconducting magnets and associated systems being used in and being developed for high energy physics are described

  10. Photoswitchable Dihydroazulene Macrocycles for Solar Energy Storage: The Effects of Ring Strain.

    Science.gov (United States)

    Vlasceanu, Alexandru; Frandsen, Benjamin N; Skov, Anders B; Hansen, Anne Schou; Rasmussen, Mads Georg; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

    2017-10-06

    Efficient energy storage and release are two major challenges of solar energy harvesting technologies. The development of molecular solar thermal systems presents one approach to address these issues by tuning the isomerization reactions of photo/thermoswitches. Here we show that the incorporation of photoswitches into macrocyclic structures is a particularly attractive solution for increasing the storage time. We present the synthesis and properties of a series of macrocycles incorporating two dihydroazulene (DHA) photoswitching subunits, bridged by linkers of varying chain length. Independent of ring size, all macrocycles exhibit stepwise, light-induced, ring-opening reactions (DHA-DHA to DHA-VHF to VHF-VHF; VHF = vinylheptafulvene) with the first DHA undergoing isomerization with a similar efficiency as the uncyclized parent system while the second (DHA-VHF to VHF-VHF) is significantly slower. The energy-releasing, VHF-to-DHA, ring closures also occur in a stepwise manner and are systematically found to proceed slower in the more strained (smaller) cycles, but in all cases with a remarkably slow conversion of the second VHF to DHA. We managed to increase the half-life of the second VHF-to-DHA conversion from 65 to 202 h at room temperature by simply decreasing the ring size. A computational study reveals the smallest macrocycle to have the most energetic VHF-VHF state and hence highest energy density.

  11. Operation of the LHC with Protons at High Luminosity and High Energy

    CERN Document Server

    Papotti, Giulia; Alemany-Fernandez, Reyes; Crockford, Guy; Fuchsberger, Kajetan; Giachino, Rossano; Giovannozzi, Massimo; Hemelsoet, Georges-Henry; Höfle, Wolfgang; Jacquet, Delphine; Lamont, Mike; Nisbet, David; Normann, Lasse; Pojer, Mirko; Ponce, Laurette; Redaelli, Stefano; Salvachua, Belen; Solfaroli Camillocci, Matteo; Suykerbuyk, Ronaldus; Uythoven, Jan; Wenninger, Jorg

    2016-01-01

    In 2015 the Large Hadron Collider (LHC) entered the first year in its second long Run, after a 2-year shutdown that prepared it for high energy. The first two months of beam operation were dedicated to setting up the nominal cycle for proton-proton operation at 6.5 TeV/beam, and culminated with the first physics with 3 nominal bunches/ring at 13 TeV CoM on 3 June. The year continued with a stepwise intensity ramp up that allowed reaching 2244 bunches/ring for a peak luminosity of ~5·10³³ cm⁻²s^{−1} and a total of just above 4 fb-1 delivered to the high luminosity experiments. Beam operation was shaped by the high intensity effects, e.g. electron cloud and macroparticle-induced fast losses (UFOs), which on a few occasions caused the first beam induced quenches at high energy. This paper describes the operational experience with high intensity and high energy at the LHC, together with the issues that had to be tackled along the way.

  12. Layout of the LER [Low Energy Ring] Arc

    International Nuclear Information System (INIS)

    Hutton, A.

    1990-01-01

    We have recently been trying to accumulate all of the information necessary to decide on the layout of the regular curved arcs of the Low Energy Ring (LER) and there have been several ABC Notes published on different aspects of the problem. This note will describe the layout that has been derived from these considerations

  13. O-Ring sealing arrangements for ultra-high vacuum systems

    Science.gov (United States)

    Kim, Chang-Kyo; Flaherty, Robert

    1981-01-01

    An all metal reusable O-ring sealing arrangement for sealing two concentric tubes in an ultra-high vacuum system. An O-ring of a heat recoverable alloy such as Nitinol is concentrically positioned between protruding sealing rings of the concentric tubes. The O-ring is installed between the tubes while in a stressed martensitic state and is made to undergo a thermally induced transformation to an austenitic state. During the transformation the O-ring expands outwardly and contracts inwardly toward a previously sized austenitic configuration, thereby sealing against the protruding sealing rings of the concentric tubes.

  14. Energy content of stormtime ring current from phase space mapping simulations

    International Nuclear Information System (INIS)

    Chen, M.W.; Schulz, M.; Lyons, L.R.

    1993-01-01

    The authors perform a model study to account for the increase in energy content of the trapped-particle population which occurs during the main phase of major geomagnetic storms. They consider stormtime particle transport in the equatorial region of the magnetosphere. They start with a phase space distribution of the ring current before the storm, created by a steady state transport model. They then use a previously developed guiding center particle simulation to map the stormtime ring current phase space, following Liouville's theorem. This model is able to account for the ten to twenty fold increase in energy content of magnetospheric ions during the storm

  15. High-energy photons and neutrinos from gamma-ray bursts

    International Nuclear Information System (INIS)

    Dar, A.

    1998-01-01

    The Hubble Space Telescope has recently discovered thousands of gigantic cometlike objects in a ring around the central star in the nearest planetary nebula. It is assumed that such circumstellar rings exist around the majority of stars. Collisions of relativistic debris from gamma-ray bursts (GRB) in dense stellar regions with such gigantic cometlike objects, which have been stripped off from the circumstellar rings by gravitational perturbations, produce detectable fluxes of high energy γ rays and neutrinos from GRBs

  16. Ring artifact correction for high-resolution micro CT

    International Nuclear Information System (INIS)

    Kyriakou, Yiannis; Prell, Daniel; Kalender, Willi A

    2009-01-01

    In high-resolution micro CT using flat detectors (FD), imperfect or defect detector elements may cause concentric-ring artifacts due to their continuous over- or underestimation of attenuation values, which often disturb image quality. We here present a dedicated image-based ring artifact correction method for high-resolution micro CT, based on median filtering of the reconstructed image and working on a transformed version of the reconstructed images in polar coordinates. This post-processing method reduced ring artifacts in the reconstructed images and improved image quality for phantom and in in vivo scans. Noise and artifacts were reduced both in transversal and in multi-planar reformations along the longitudinal axis. (note)

  17. Ring rotational speed trend analysis by FEM approach in a Ring Rolling process

    Science.gov (United States)

    Allegri, G.; Giorleo, L.; Ceretti, E.

    2018-05-01

    Ring Rolling is an advanced local incremental forming technology to fabricate directly precise seamless ring-shape parts with various dimensions and materials. In this process two different deformations occur in order to reduce the width and the height of a preform hollow ring; as results a diameter expansion is obtained. In order to guarantee a uniform deformation, the preform is forced toward the Driver Roll whose aim is to transmit the rotation to the ring. The ring rotational speed selection is fundamental because the higher is the speed the higher will be the axial symmetry of the deformation process. However, it is important to underline that the rotational speed will affect not only the final ring geometry but also the loads and energy needed to produce it. Despite this importance in industrial environment, usually, a constant value for the Driver Roll angular velocity is set so to result in a decreasing trend law for the ring rotational speed. The main risk due to this approach is not fulfilling the axial symmetric constrain (due to the diameter expansion) and to generate a high localized ring section deformation. In order to improve the knowledge about this topic in the present paper three different ring rotational speed trends (constant, linearly increasing and linearly decreasing) were investigated by FEM approach. Results were compared in terms of geometrical and dimensional analysis, loads and energies required.

  18. White Ring; White ring

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, H.; Yuzawa, H. [Nikken Sekkei Ltd., Osaka (Japan)

    1998-01-05

    White Ring is a citizen`s gymnasium used for figure skating and short track speed skating games of 18th Winter Olympic Games in 1998. White Ring is composed of a main-arena and a sub-arena. For the main-arena with an area 41mtimes66m, an ice link can be made by disengaging the potable floor and by flowing brine in the bridged polystyrene pipes embedded in the concrete floor. Due to the fortunate groundwater in this site, well water is used for the outside air treatment energy in 63% during heating and in 35% during cooling. Ammonia is used as a cooling medium for refrigerating facility. For the heating of audience area in the large space, heat load from the outside is reduced by enhancing the heat insulation performance of the roof of arena. The audience seats are locally heated using heaters. For the White Ring, high quality environment is realized for games through various functions of the large-scale roof of the large space. Success of the big event was expected. 15 figs., 4 tabs.

  19. Siberian Snakes in high-energy accelerators

    International Nuclear Information System (INIS)

    Mane, S R; Shatunov, Yu M; Yokoya, K

    2005-01-01

    We review modern techniques to accelerate spin-polarized beams to high energy and to preserve their polarization in storage rings. Crucial to the success of such work is the use of so-called Siberian Snakes. We explain these devices and the reason for their necessity. Closely related to Snakes is the concept of 'spin rotators'. The designs and merits of several types of Snakes and spin rotators are examined. Theoretical work with Snakes and spin rotators, and experimental results from several storage rings, are reviewed, including the so-called Snake resonances. (topical review)

  20. Antiproton chain of the FAIR storage rings

    International Nuclear Information System (INIS)

    Katayama, T; Kamerdzhiev, V; Lehrach, A; Maier, R; Prasuhn, D; Stassen, R; Stockhorst, H; Herfurth, F; Lestinsky, M; Litvinov, Yu A; Steck, M; Stöhlker, T

    2015-01-01

    In the Modularized Start Version of the Facility of Antiproton and Ion Research (FAIR) at Darmstadt Germany, the 3 GeV antiprotons are precooled in the collector ring and accumulated in the high energy storage ring (HESR). They are further accelerated to 14 GeV or decelerated to 1 GeV for the experiments with a high-density internal target. The powerful beam cooling devices, stochastic cooling and electron cooling will support the provision of a high-resolution antiproton beam. The other option of FAIR is to prepare the low energy, 300 keV antiproton beam connecting the existing storage rings ESR and CRYRING with HESR. Beam physics issues related with these concepts are described. (paper)

  1. High energy photons and neutrinos from gamma ray bursts

    International Nuclear Information System (INIS)

    Dar, A.

    1998-01-01

    The Hubble space telescope has recently discovered thousands of gigantic comet-like objects in a ring around the central star in the nearest planetary nebula. It is suggested that such circumstellar rings exist around most of stars. Collisions of the relativistic debris from gamma ray bursts in dense stellar regions with such gigantic comet-like objects, which have been stripped off from the circumstellar rings by gravitational perturbations, produce detectable fluxes of high energy gamma-rays and neutrinos from gamma ray bursts

  2. Development of high-performance sintered friction material for synchronizer ring; Koseino shoketsu synchronizer ring masatsu zairyo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Miyajima, K; Fuwa, Y; Okajima, H; Yoshikawa, K [Toyota Motor Corp., Aichi (Japan); Nakamura, M [Japan Powder Metallurgy Co. Ltd., Tokyo (Japan)

    1997-10-01

    Increasing vehicle speed and power, high-performance synchronizer ring of manual transmission is required. We develop double layer sintered synchronizer ring for high performance and cost reduction. The main structure is consisted of ferrous sinter for high strength. In this paper, friction materials of sintered synchronizer ring are studied. We can get the good friction and anti-wear property by means of hard particles (FeTi, ZrO2), solid lubricant (Graphite) and suitable porosity in brass sinter matrix. And we also achieve high joining strength between double layers adding Cu-P material. 6 refs., 13 figs., 2 tabs.

  3. Fast northward energy transfer in the Atlantic due to Agulhas Rings

    NARCIS (Netherlands)

    van Sebille, Erik; van Leeuwen, P.J.

    2007-01-01

    The adiabatic transit time of wave energy radiated by an Agulhas ring released in the South Atlantic Ocean to the North Atlantic Ocean is investigated in a two-layer ocean model. Of particular interest is the arrival time of baroclinic energy in the northern part of the Atlantic, because it is

  4. Estimates of CSR Instability Thresholds for Various Storage Rings

    CERN Document Server

    Zimmermann, Frank

    2010-01-01

    We review the key predictions and conditions by several authors for the onset of longitudinal instabilities due to coherent synchrotron radiation (CSR), and evaluate them numerically for various storage rings, namely the KEKB High Energy Ring (HER) & Low Energy Ring (LER), SuperKEKB HER & LER, old and new designs of the SuperKEKB Damping Ring (DR), SuperB HER & LER, CLIC DR (2009 and 2010 design parameters), SLC DR, and ATF DR. We show that the theoretical uncertainty in the instability onset is at least at the level of 20-30% in bunch intensity. More importantly, we present some doubts about the general applicability for many of these storage rings of some commonly used formulae. To cast further light on these questions, an experiment at lower beam energy on the ATF Damping Ring is proposed.

  5. The LEP e+e−ring at the energy frontier of circular lepton colliders

    CERN Document Server

    Hofmann, Albert

    2016-01-01

    The Large Electron Positron ring (LEP) was a circular lepton collider at CERN. It operated at beam energies around 47GeV to produce the neutral Z0 particle and above 80 GeV to create pairs of the charged W± bosons. At these high energies the emission of synchrotron radiation was important and demanded a very high voltage of the RF-system. It also influenced the choice of many other machine parameters. This presentation tries to show how the basic accelerator physics was used to optimize the machine and to find innovative solutions for some problems: magnets with concrete between the laminations, modulated cavities, Nb-Cu superconducting cavities, nonevaporable getter pumps, optics analysis from multi-turn data and many more.

  6. Precision ring rolling technique and application in high-performance bearing manufacturing

    Directory of Open Access Journals (Sweden)

    Hua Lin

    2015-01-01

    Full Text Available High-performance bearing has significant application in many important industry fields, like automobile, precision machine tool, wind power, etc. Precision ring rolling is an advanced rotary forming technique to manufacture high-performance seamless bearing ring thus can improve the working life of bearing. In this paper, three kinds of precision ring rolling techniques adapt to different dimensional ranges of bearings are introduced, which are cold ring rolling for small-scale bearing, hot radial ring rolling for medium-scale bearing and hot radial-axial ring rolling for large-scale bearing. The forming principles, technological features and forming equipments for three kinds of precision ring rolling techniques are summarized, the technological development and industrial application in China are introduced, and the main technological development trend is described.

  7. Experience with a high-brightness storage ring: the NSLS 750 MeV vuv ring

    International Nuclear Information System (INIS)

    Galayda, J.

    1984-01-01

    The NSLS vuv ring is the first implementation of the proposals of R. Chasman and G.K. Green for a synchrotron radiation source with enhanced brightness: its lattice is a series of achromatic bends with two zero-gradient dipoles each, giving small damped emittance; and these bends are connected by straight sections with zero dispersion to accommodate wigglers and undulators without degrading the radiation damping properties of the ring. The virtues of the Chasman-Green lattice, its small betatron and synchrotron emittances, may be understood with some generality; e.g. the electron γm 0 c 2 energy and the number of achromatic bends M sets a lower limit on the betatron emittance of e/sub x/ > 7.7 x 10 -13 γ 2 /M meter-radians. There is strong interest in extrapolation of this type of lattice to 6 GeV and to 32 achromatic bends. The subject of this report is the progress toward achieving performance in the vuv ring limited by the radiation damping parameters optimized in its design. 14 refs., 4 figs., 1 tab

  8. High-energy high-luminosity electron-ion collider eRHIC

    International Nuclear Information System (INIS)

    Litvinenko, V.N.; Ben-Zvi, I.; Hammons, L.; Hao, Y.; Webb, S.

    2011-01-01

    In this paper, we describe a future electron-ion collider (EIC), based on the existing Relativistic Heavy Ion Collider (RHIC) hadron facility, with two intersecting superconducting rings, each 3.8 km in circumference. The replacement cost of the RHIC facility is about two billion US dollars, and the eRHIC will fully take advantage and utilize this investment. We plan adding a polarized 5-30 GeV electron beam to collide with variety of species in the existing RHIC accelerator complex, from polarized protons with a top energy of 325 GeV, to heavy fully-striped ions with energies up to 130 GeV/u. Brookhaven's innovative design, is based on one of the RHIC's hadron rings and a multi-pass energy-recovery linac (ERL). Using the ERL as the electron accelerator assures high luminosity in the 10 33 -10 34 cm -2 sec -1 range, and for the natural staging of eRHIC, with the ERL located inside the RHIC tunnel. The eRHIC will provide electron-hadron collisions in up to three interaction regions. We detail the eRHIC's performance in Section 2. Since first paper on eRHIC paper in 2000, its design underwent several iterations. Initially, the main eRHIC option (the so-called ring-ring, RR, design) was based on an electron ring, with the linac-ring (LR) option as a backup. In 2004, we published the detailed 'eRHIC 0th Order Design Report' including a cost-estimate for the RR design. After detailed studies, we found that an LR eRHIC has about a 10-fold higher luminosity than the RR. Since 2007, the LR, with its natural staging strategy and full transparency for polarized electrons, became the main choice for eRHIC. In 2009, we completed technical studies of the design and dynamics for MeRHIC with 3-pass 4 GeV ERL. We learned much from this evaluation, completed a bottom-up cost estimate for this $350M machine, but then shelved the design. In the same year, we turned again to considering the cost-effective, all-in-tunnel six-pass ERL for our design of the high-luminosity eRHIC. In it

  9. A Harmonic Kicker Scheme for the Circulator Cooler Ring in the Proposed Medium Energy Electron-Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Nissen, Edward W.; Hutton, Andrew M.; Kimber, Andrew J.

    2013-06-01

    The current electron cooler design for the proposed Medium Energy Electron-Ion collider (MEIC) at Jefferson Lab utilizes a circulator ring for reuse of the cooling electron bunch up to 100 times to cool the ion beams. This cooler requires a fast kicker system for injecting and extracting individual bunches in the circulator ring. Such a kicker must work at a high repetition rate, up to 7.5 to 75 MHz depending on the number of turns in the recirculator ring. It also must have a very short rise and fall time (of order of 1 ns) such that it will kick an individual bunch without disturbing the others in the ring. Both requirements are orders of magnitude beyond the present state-of-the-art as well as the goals of other on-going kicker R&D programs such as that for the ILC damping rings. In this paper we report a scheme of creating this fast, high repetition rate kicker by combining RF waveforms at multiple frequencies to create a kicker waveform that will, for example, kick every eleventh bunch while leaving the other ten unperturbed. We also present a possible implementation of this scheme as well as discuss its limitations.

  10. Strategy of ring-shaped aggregates in excitation energy transfer for removing disorder-induced shielding

    International Nuclear Information System (INIS)

    Tei, Go; Nakatani, Masatoshi; Ishihara, Hajime

    2013-01-01

    Peripheral light harvesting complex (LH2), which is found in photosynthetic antenna systems of purple photosynthetic bacteria, has important functions in the photosynthetic process, such as harvesting sunlight and transferring its energy to the photosynthetic reaction center. The key component in excitation energy transfer (EET) between LH2s is B850, which is a characteristic ring-shaped aggregate of pigments usually formed by 18 or 16 bacteriochlorophylls in LH2. We theoretically study the strategy of the ring-shaped aggregate structure, which maximizes EET efficiency, by using the standard Frenkel exciton model and the self-consistent calculation method for the Markovian quantum master equation and Maxwell equation. As a result, we have revealed a simple but ingenious strategy of the ring-shaped aggregate structure. The combination of three key properties of the ring unit system maximizes the EET efficiency, namely the large dipole moment of aggregates causes the basic improvement of EET efficiency, and the isotropic nature and the large occupying area are critically effective to remove the disorder-induced shielding that inhibits EET in the presence of the randomness of orientation and alignment of carriers of excitation energy. (paper)

  11. Strategy of ring-shaped aggregates in excitation energy transfer for removing disorder-induced shielding

    Science.gov (United States)

    Tei, Go; Nakatani, Masatoshi; Ishihara, Hajime

    2013-06-01

    Peripheral light harvesting complex (LH2), which is found in photosynthetic antenna systems of purple photosynthetic bacteria, has important functions in the photosynthetic process, such as harvesting sunlight and transferring its energy to the photosynthetic reaction center. The key component in excitation energy transfer (EET) between LH2s is B850, which is a characteristic ring-shaped aggregate of pigments usually formed by 18 or 16 bacteriochlorophylls in LH2. We theoretically study the strategy of the ring-shaped aggregate structure, which maximizes EET efficiency, by using the standard Frenkel exciton model and the self-consistent calculation method for the Markovian quantum master equation and Maxwell equation. As a result, we have revealed a simple but ingenious strategy of the ring-shaped aggregate structure. The combination of three key properties of the ring unit system maximizes the EET efficiency, namely the large dipole moment of aggregates causes the basic improvement of EET efficiency, and the isotropic nature and the large occupying area are critically effective to remove the disorder-induced shielding that inhibits EET in the presence of the randomness of orientation and alignment of carriers of excitation energy.

  12. Development of new radiation sources using high energy electrons and their applications

    International Nuclear Information System (INIS)

    Tomimasu, Takio

    1992-01-01

    Present and future of compact electron storage rings used for lithography, free electron laser (FEL) and angiography are reviewed and discussed. Recent development of the compact rings with insertion devices capable of storing 1-A beam enable these prospective applications and generations of strong backward compton scattered γ-rays and any kind of elliptically polarizing photons. The high-energy, high current and small-energy spread beam acceleration using conventional type electron linacs is also discussed for the generations of UV-FEL and slow positrons. (author)

  13. Analysis of the wake field effects in the PEP-II storage rings with extremely high currents

    Energy Technology Data Exchange (ETDEWEB)

    Novokhatski, A., E-mail: novo@slac.stanford.edu; Seeman, J.; Sullivan, M.

    2014-01-21

    We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high-current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves, shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; and beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

  14. The evolution of high energy accelerators

    International Nuclear Information System (INIS)

    Courant, E.D.

    1994-01-01

    Accelerators have been devised and built for two reasons: In the first place, by physicists who needed high energy particles in order to have a means to explore the interactions between particles that probe the fundamental elementary forces of nature. And conversely, sometimes accelerator builders produce new machines for higher energy than ever before just because it can be done, and then challenge potential users to make new discoveries with the new means at hand. These two approaches or motivations have gone hand in hand. This lecture traces how high energy particle accelerators have grown from tools used for esoteric small-scale experiments to the gigantic projects of today. So far all the really high-energy machines built and planned in the world--except the SLC--have been ring accelerators and storage rings using the strong-focusing method. But this method has not removed the energy limit, it has only pushed it higher. It would seem unlikely that one can go beyond the Large Hadron Collider (LHC)--but in fact a workshop was held in Sicily in November 1991, concerned with the question of extrapolating to 100 TeV. Other acceleration and beam-forming methods are now being discussed--collective fields, laser acceleration, wake-field accelerators etc., all aimed primarily at making linear colliders possible and more attractive than with present radiofrequency methods. So far it is not entirely clear which of these schemes will dominate particle physics in the future--maybe something that has not been thought of as yet

  15. An Alternative Derivation of the Energy Levels of the "Particle on a Ring" System

    Science.gov (United States)

    Vincent, Alan

    1996-10-01

    All acceptable wave functions must be continuous mathematical functions. This criterion limits the acceptable functions for a particle in a linear 1-dimensional box to sine functions. If, however, the linear box is bent round into a ring, acceptable wave functions are those which are continuous at the 'join'. On this model some acceptable linear functions become unacceptable for the ring and some unacceptable cosine functions become acceptable. This approach can be used to produce a straightforward derivation of the energy levels and wave functions of the particle on a ring. These simple wave mechanical systems can be used as models of linear and cyclic delocalised systems such as conjugated hydrocarbons or the benzene ring. The promotion energy of an electron can then be used to calculate the wavelength of absorption of uv light. The simple model gives results of the correct order of magnitude and shows that, as the chain length increases, the uv maximum moves to longer wavelengths, as found experimentally.

  16. Topological ring currents in the "empty" ring of benzo-annelated perylenes.

    Science.gov (United States)

    Dickens, Timothy K; Mallion, Roger B

    2011-01-27

    Cyclic conjugation in benzo-annelated perylenes is examined by means of the topological π-electron ring currents calculated for each of their constituent rings, in a study that is an exact analogy of a recent investigation by Gutman et al. based on energy-effect values for the corresponding rings in each of these structures. "Classical" approaches, such as Kekulé structures, Clar "sextet" formulas, and circuits of conjugation, predict that the central ring in perylene is "empty" and thus contributes negligibly to cyclic conjugation. However, conclusions from the present calculations of topological ring currents agree remarkably with those arising from the earlier study involving energy-effect values in that, contrary to what would be predicted from the classical approaches, rings annelated in an angular fashion relative to the central ring of these perylene structures materially increase the extent of that ring's involvement in cyclic conjugation. It is suggested that such close quantitative agreement between the predictions of these two superficially very different indices (energy effect and topological ring current) might be due to the fact that, ultimately, both depend, albeit in ostensibly quite different ways, only on an adjacency matrix that contains information about the carbon-carbon connectivity of the conjugated system in question.

  17. Status of the MIT-Bates South Hall Ring commissioning

    International Nuclear Information System (INIS)

    Flanz, J.B.; Jacobs, K.D.; McAllister, B.; Averill, R.; Bradley, S.; Carter, A.; Dow, K.; Farkondeh, M.; Ihloff, E.; Kowalski, S.

    1993-01-01

    The MIT-Bates South Hall Ring construction project is now nearly complete. At this time the Energy Compression System, the SHR Injection Line and the South Hall Ring itself are complete. The SHR Extraction Line is complete but has not been connected to the ring. Commissioning with beam of the completed beam lines has been started. The MIT-Bates South Hall Ring (SHR) is an electron storage ring used with the 1 GeV Bates electron accelerator to increase the effective duty factor and luminosity. A beam can be stored for use with an internal target, thus allowing for high duty factor, high luminosity experiments. External beams with high duty factor can be obtained using resonant extraction. The new systems associated with the SHR include the Energy Compression System (ECS), the Injection line, and the Extraction line. The authors have commissioned the ECS, the new injection line and the SHR without RF. This includes transporting beam, measuring beam phase space parameters using critical injection elements including a high voltage electrostatic septum, a fast beam kicker, and storing a beam in the SHR

  18. High-Power Ka-Band Window and Resonant Ring

    International Nuclear Information System (INIS)

    Jay L. Hirshfield

    2006-01-01

    A stand-alone 200 MW rf test station is needed for carrying out development of accelerator structures and components for a future high-gradient multi-TeV collider, such as CLIC. A high-power rf window is needed to isolate the test station from a structure element under test. This project aimed to develop such a window for use at a frequency in the range 30-35 GHz, and to also develop a high-power resonant ring for testing the window. During Phase I, successful conceptual designs were completed for the window and the resonant ring, and cold tests of each were carried out that confirmed the designs

  19. Pulsed Power Applications in High Intensity Proton Rings

    CERN Document Server

    Zhang, Wu; Ducimetière, Laurent; Fowler, Tony; Kawakubo, Tadamichi; Mertens, Volker; Sandberg, Jon; Shirakabe, Yoshihisa

    2005-01-01

    The pulsed power technology has been applied in particle accelerators and storage rings for over four decades. It is most commonly used in injection, extraction, beam manipulation, source, and focusing systems. These systems belong to the class of repetitive pulsed power. In this presentation, we review and discuss the history, present status, and future challenge of pulsed power applications in high intensity proton accelerators and storage rings.

  20. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  1. Stability of large orbit, high-current particle rings

    International Nuclear Information System (INIS)

    Lovelace, R.V.E.

    1994-01-01

    A review is made of theory of the low-frequency stability of large orbit, high-current particle rings which continue to be of interest for compact fusion systems. The precession mode was the first mode predicted by Furth and observed by Christofilos to be unstable under certain conditions. Subsequently, many detailed studies have been made of the stability of particle rings- different modes, different ring geometries, systems with/without a toroidal B field, and sytems with/without a current carrying plasma component. The possibly dangerous modes are still thought to include the precession mode, the tilting mode, and the low order kink modes. copyright American Institute of Physics

  2. A radio frequency ring electrode cooler for low-energy ion beams

    International Nuclear Information System (INIS)

    Heinz, S.; Aeystoe, J.; Habs, D.; Hegewisch, S.; Huikari, J.; Nieminen, A.; Rinta-Antila, S.; Schumann, M.; Szerypo, J.

    2004-01-01

    We are investigating a new concept for ion confinement while buffer-gas-cooling low-energy ion beams. Instead of applying the well-established technique of Radio Frequency Quadrupoles (RFQs) where the ions are transversely confined by a quadratic-pseudo potential we are using a stack of thin ring electrodes supplied by an RF field (RF funnel) which creates a box-shaped potential well. In Monte Carlo simulations we have investigated the transmission behavior and cooling performance of the RF funnel. First experimental investigations with ion currents up to 20 nA revealed a promising transmission characteristic which qualifies the RF funnel as high-current cooler

  3. Emittance measurements in low energy ion storage rings

    Science.gov (United States)

    Hunt, J. R.; Carli, C.; Resta-López, J.; Welsch, C. P.

    2018-07-01

    The development of the next generation of ultra-low energy antiproton and ion facilities requires precise information about the beam emittance to guarantee optimum performance. In the Extra-Low ENergy Antiproton storage ring (ELENA) the transverse emittances will be measured by scraping. However, this diagnostic measurement faces several challenges: non-zero dispersion, non-Gaussian beam distributions due to effects of the electron cooler and various systematic errors such as closed orbit offsets and inaccurate rms momentum spread estimation. In addition, diffusion processes, such as intra-beam scattering might lead to emittance overestimates. Here, we present algorithms to efficiently address the emittance reconstruction in presence of the above effects, and present simulation results for the case of ELENA.

  4. Beam Instrumentation for the Spallation Neutron Source Ring

    International Nuclear Information System (INIS)

    Witkover, R. L.; Cameron, P. R.; Shea, T. J.; Connolly, R. C.; Kesselman, M.

    1999-01-01

    The Spallation Neutron Source (SNS) will be constructed by a multi-laboratory collaboration with BNL responsible for the transfer lines and ring. The 1 MW beam power necessitates careful monitoring to minimize un-controlled loss. This high beam power will influence the design of the monitors in the high energy beam transport line (HEBT) from linac to ring, in the ring, and in the ring-to-target transfer line (RTBT). The ring instrumentation must cover a 3-decade range of beam intensity during accumulation. Beam loss monitoring will be especially critical since un-controlled beam loss must be kept below 10 -4 . A Beam-In-Gap (BIG) monitor is being designed to assure out-of-bucket beam will not be lost in the ring

  5. Simulation of a resonant-type ring magnet power supply with multiple resonant cells and energy storage chokes

    International Nuclear Information System (INIS)

    Kim, J.M.S.; Blackmore, E.W.; Reiniger, K.W.

    1992-01-01

    For the TRIUMF KAON Factory Booster Ring, a resonant-type magnet power supply has been proposed for the dipole magnet excitation. The Booster Ring magnet power supply system based on resonant circuits, coupled with distributed energy make-up networks, is a complex system, sensitive to many system parameters. When multiple resonant cells, each with its own energy make-up network, are connected in a ring, it is very difficult to derive closed-form solutions to determine the operating conditions of the power supply system. A meaningful way to understand and analyze such a complex system is to use a simulation tool. This paper presents the analysis of operating conditions of the resonant-type ring magnet power supply with multiple resonant cells, using the circuit simulation tool, SPICE. The focus of the study is on the effect of circuit parameter variations in energy storage chokes

  6. Levitation properties of a ring-shaped flywheel supported by high Tc superconducting levitation

    International Nuclear Information System (INIS)

    Teshima, Hidekazu; Tawara, Taichi; Shimada, Ryuichi.

    1997-01-01

    In this paper we propose a new combination of high T c superconducting levitation and ring-shaped flywheel energy storage systems. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub, because it is a non-contact and automatically stable levitation without any control systems. The levitation properties such as static and dynamic lateral stiffnesses, lateral damping, and lateral vibration during rotation have been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The spring constant increased as the levitation gap height decreased, and the dynamic spring constant was slightly higher than the static constant. The damping coefficient increased as the gap height decreased and the vibration amplitude increased. The experimental critical speed was in good agreement with the calculated one using a one-degree of freedom model. Finally, the possibility of large-scaled practical systems is discussed from the viewpoint of superconducting levitation. (author)

  7. Experiments with highly-charged heavy-ions performed at the storage ring ESR

    International Nuclear Information System (INIS)

    Mokler, P.H.

    1992-01-01

    The new heavy ion accelerator facility SIS/ESR was inaugurated in April 1990. During 1991 the experimental storage ring, ESR, has been commissioned. Highly-charged heavy ions from O 8+ up to Bi 82+ were successfully accumulated, cooled, and stored in the ring. Now all highly-charged, heavy ions can be provided for experiments at comfortable storage times and at energies roughly between 100 and 500 MeV/u. A report on the achievements and on the first experimental results will be given. For the experiments, special emphasis is put on capture processes in the electron cooler, i.e. on radiative and dielectronic recombination processes as well as on capture events of bound target electrons from a gas jet. In this case, the capture leads either directly (REC) or by cascading to X-ray emission, which is also exploited for a precision spectroscopy of the structure of the heaviest ions. Another exciting topic is the radioactive decay of highly charged ions: For instance the β-decay into bound atomic states, which is not possible for neutral atoms, was studied for stored naked Dy ions. (orig.)

  8. Autumn study on storage rings

    CERN Multimedia

    1974-01-01

    The first two weeks of October have seen storage ring people from accelerator Laboratories throughout the world at CERN to study the fundamental problems of very high energy protonproton colliding beam machines.

  9. Damping Ring R&D at CESR-TA

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, David L. [Cornell Univ., Ithaca, NY (United States). Dept. of Physics

    2015-01-23

    Accelerators that collide high energy beams of matter and anti-matter are essential tools for the investigation of the fundamental constituents of matter, and the search for new forms of matter and energy. A “Linear Collider” is a machine that would bring high energy and very compact bunches of electrons and positrons (anti-electrons) into head-on collision. Such a machine would produce (among many other things) the newly discovered Higgs particle, enabling a detailed study of its properties. Among the most critical and challenging components of a linear collider are the damping rings that produce the very compact and intense beams of electrons and positrons that are to be accelerated into collision. Hot dilute particle beams are injected into the damping rings, where they are compressed and cooled. The size of the positron beam must be reduced more than a thousand fold in the damping ring, and this compression must be accomplished in a fraction of a second. The cold compact beams are then extracted from the damping ring and accelerated into collision at high energy. The proposed International Linear Collider (ILC), would require damping rings that routinely produce such cold, compact and intense beams. The goal of the Cornell study was a credible design for the damping rings for the ILC. Among the technical challenges of the damping rings; the development of instrumentation that can measure the properties of the very small beams in a very narrow window of time, and mitigation of the forces that can destabilize the beams and prevent adequate cooling, or worse lead to beam loss. One of the most pernicious destabilizing forces is due to the formation of clouds of electrons in the beam pipe. The electron cloud effect is a phenomenon in particle accelerators in which a high density of low energy electrons, build up inside the vacuum chamber. At the outset of the study, it was anticipated that electron cloud effects would limit the intensity of the positron ring

  10. Beam dynamics in Compton ring gamma sources

    Directory of Open Access Journals (Sweden)

    Eugene Bulyak

    2006-09-01

    Full Text Available Electron storage rings of GeV energy with laser pulse stacking cavities are promising intense sources of polarized hard photons which, via pair production, can be used to generate polarized positron beams. In this paper, the dynamics of electron bunches circulating in a storage ring and interacting with high-power laser pulses is studied both analytically and by simulation. Both the common features and the differences in the behavior of bunches interacting with an extremely high power laser pulse and with a moderate pulse are discussed. Also considerations on particular lattice designs for Compton gamma rings are presented.

  11. Cooling rings for TeV colliders

    International Nuclear Information System (INIS)

    Palmer, R.B.

    1985-02-01

    Consideration is given to quantum fluctuations, intra beam scattering, cooling rates, and ring acceptance in order to see if one can obtain a normalized emittance of 10 -8 in any plausible cooling ring. It is concluded that only a small gain is obtained by varying the partition functions, but a very significant gain is made by using higher bending fields. The ring is found to get bigger if the magnet apertures are increased. The ring diameter is found to increase if the momentum spread of the beam is reduced. It is shown that the power can be reduced by allowing a high beamstrahlung energy loss resulting in higher current in the cooling ring. Parameters are also given for a 10 -7 m radian emittance case

  12. CIRS High-Resolution Thermal Scans and the Structure of Saturn's B Ring

    Science.gov (United States)

    Brooks, S. M.; Spilker, L. J.; Showalter, M.; Pilorz, S.; Edgington, S. G.

    2017-12-01

    The flyby of Titan on November 29, 2016, sent the Cassini spacecraft on a trajectory that would take it within 10,000 kilometers of Saturn's F ring multiple times before a subsequent Titan encounter on April 22, 2017, would send it on ballistic trajectory carrying it between Saturn's cloud tops and the planet's D ring for several flybys. This geometry has proven beneficial for high-resolution studies of the rings, not just because of Cassini's proximity to the rings, but also because of the spacecraft's high elevation angle above the rings, which reduces the foreshortening that tends to degrade resolution in the ring plane. We will report on several observations of Saturn's main rings at the high spatial resolutions enabled by the end-of-mission geometry, particulary the B ring, with the Composite Infrared Spectrometer onboard Cassini during the F-ring and proximal orbits. CIRS' three infrared detectors cover a combined spectral range of 10 to 1400 cm-1 (1 mm down to 7 microns). We focus on data from Focal Plane 1, which covers the 10 to 600 cm-1 range (1 mm to 16 microns). The apodized spectral resolution of the instrument can be varied from 15 cm-1 to 0.5 cm-1 (Flasar et al. 2004). FP1's wavelength range makes it well-suited to sensing thermal emission from objects at temperatures typical of Saturn's rings. Correlating ring optical depth with temperatures retrieved from scans of the face of the rings exposed to direct solar illumination (the lit face) and the opposite (unlit) face suggests differences in ring structure or particle transport between the lit and unlit sides of the rings in different regions of the B ring. Lit side temperatures in the core of the B ring range between 82 and 87 K; temperatures on the unlit side of the core vary from 66 K up to 74 K. Ferrari and Reffet (2013) and Pilorz et al. (2015) published thorough analyses of the thermal throughput across this optically thick ring. We will discuss these recent CIRS rings observations and their

  13. Plasma-ring, fast-opening switch

    International Nuclear Information System (INIS)

    Hartman, C.W.; Eddleman, J.; Hammer, J.H.

    1986-01-01

    The authors discuss a fast-opening switch concept based on magnetically confined plasma rings, PROS (for Plasma Ring Opening Switch). In PROS, the plasma ring, confined by Bθ /sub and B/poloidal /sub fields of a compact torus, provide a low mass, localized conduction path between coaxial electrodes. To operate the switch, driver current is passed across the electrodes through the ring, storing inductive energy in external inductance and between the electrodes on the driver side of the ring. The ring is accelerated away from the driver by the field of the driver current and passes over a load gap transferring the current to the load. The authors distinguish two configurations in PROS, straight PROS where the electrodes are coaxial cylinders, and cone PROS with conical electrodes. In straight PROS ring acceleration takes place during the inductive store period as in foil switches, but with the localized ring providing the current path. Increased performance is predicted for the cone PROS (see figure) which employs compression of the ring in the cone during the inductive store period. Here, the B/θ /sub field of the driver forces the ring towards the apex of the cone but the force is in near balance with the opposing component of the radial equilibrium force of the ring along the cone. As a result, the ring undergoes a slow, quasistatic compression limited only by resistive decay of the ring field. Slow compression allows inductive storage with low-power drivers (homopoloar, magneto cumulative generators, high C-low V capacitor banks, etc.). Near the apex of the cone, near peak compression, the ring is allowed to enter a straight coaxial section where, because of low-mass, it rapidly accelerates to high velocity and crosses the load gap

  14. SOR-RING: an electron storage ring dedicated to spectroscopy, 2

    International Nuclear Information System (INIS)

    Kitamura, H.; Miyahara, T.; Sato, S.; Watanabe, M.; Mitani, S.

    1976-01-01

    A 300 MeV electron storage ring to be used exclusively as a synchrotron radiation source for spectroscopy has been constructed in Institute for Nuclear Study (INS), University of Tokyo, Tanashi. Its useful spectral range lies between 40 and 2200 A. The 1.3 GeV electron synchrotron of INS currently being operated for high energy particle experiments serves as an injector. Electron beams are extracted from the synchrotron at 300 MeV, transported about twenty meters, and injected to the ring one pulse per second. In the test operation a current of 10 mA was stored with a lifetime of one hour, while the design goal determined by the Touschek effect is 100 mA with one hour, for operation in 300 MeV. Increase of operating energy up to 375 MeV is feasible with a minor modification of the present design. (auth.)

  15. Polarized particles in storage rings

    International Nuclear Information System (INIS)

    Derbenev, Ya.S.; Kondratenko, A.M.; Serednyakov, S.I.; Skrinskij, A.N.; Tumajkin, G.M.; Shatunov, Yu.M.

    1977-01-01

    Experiments with polarized beams on the VEPP-2M and SPEAK storage rings are described. Possible methods of producing polarized particle beams in storage rings as well as method of polarization monitoring are counted. Considered are the processes of radiation polarization of electrons and positrons. It is shown, that to preserve radiation polarization the introduction of regions with a strong sign-variable magnetic field is recommended. Methods of polarization measurement are counted. It is suggested for high energies to use dependence of synchrotron radiation power on transverse polarization of electrons and positrons. Examples of using polarizability of colliding beams in storage rings are presented

  16. The high energy accelerator program in Japan

    International Nuclear Information System (INIS)

    Ozaki, S.

    1987-01-01

    The author observes that in order to survey the intentions of Japanese high energy physicists and to make a recommendation to the High Energy Committee on future plans for high energy physics in Japan, including accelerators after TRISTAN, international collaboration projects and non-accelerator physics, a subcommittee of fifteen members is formed. The committee recommendation reads: A) For a new energy frontier, 1. Immediate initiation of R/D efforts for an e/sup +/e/sup -/ linear collider of TeV class, constructs a possible home-based facility, 2. Promotes international collaborative experiments using the SSC for the hadron sector, B) As projects of immediate concern: 1. The energy of the TRISTAN main ring increases further makes a possible low energy, high luminosity e/sup +/e/sup -/ collider operation in the TRISTAN complex, 2. The intensity of the 12 GeV PS at KEK increases, 3. Experiments in non-accelerator particle physics are promoted. In this contribution, the current status of the TRISTAN project and some of the R/D program on accelerator technology are reported

  17. High-precision X-ray spectroscopy of highly-charged ions at the experimental storage ring using silicon microcalorimeters

    Science.gov (United States)

    Scholz, Pascal A.; Andrianov, Victor; Echler, Artur; Egelhof, Peter; Kilbourne, Caroline; Kiselev, Oleg; Kraft-Bermuth, Saskia; McCammon, Dan

    2017-10-01

    X-ray spectroscopy on highly charged heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. One limitation of the current accuracy of such experiments is the energy resolution of available X-ray detectors for energies up to 100 keV. To improve this accuracy, a novel detector concept, namely the concept of microcalorimeters, is exploited for this kind of measurements. The microcalorimeters used in the present experiments consist of silicon thermometers, ensuring a high dynamic range, and of absorbers made of high-Z material to provide high X-ray absorption efficiency. Recently, besides an earlier used detector, a new compact detector design, housed in a new dry cryostat equipped with a pulse tube cooler, was applied at a test beamtime at the experimental storage ring (ESR) of the GSI facility in Darmstadt. A U89+ beam at 75 MeV/u and a 124Xe54+ beam at various beam energies, both interacting with an internal gas-jet target, were used in different cycles. This test was an important benchmark for designing a larger array with an improved lateral sensitivity and statistical accuracy.

  18. Challenge of high energy radiation dosimetry and protection

    International Nuclear Information System (INIS)

    Nelson, W.R.; Jenkins, T.M.

    1976-08-01

    An accelerator health physicist can make contributions in many fields of science in addition to the various operational tasks that he is charged with. He can support others in his laboratory by designing shielding for new accelerators and storage rings, by consulting with experimenters on background radiation problems that they may encounter, by helping the high energy physicist select appropriate radiation sources for checking out his equipment, by providing him with low energy atomic and nuclear physics calculations, and many other ways. Most of all, he can perform and publish research using the many tools and techniques that are at his disposal at a high-energy accelerator laboratory

  19. Cryogenic Concept for the Low-energy Electrostatic Cryogenic Storage Ring (CSR) at MPI-K in Heidelberg

    International Nuclear Information System (INIS)

    Hahn, R. von; Andrianarijaona, V.; Crespo Lopez-Urrutia, J. R.; Fadil, H.; Grieser, M.; Mallinger, V.; Orlov, D. A.; Schroeter, C. D.; Schwalm, D.; Ullrich, J.; Weber, T.; Wolf, A.; Haberstroh, Ch.; Quack, H.; Rappaport, M.; Zajfman, D.

    2006-01-01

    At the Max-Planck-Institut fuer Kernphysik in Heidelberg a next generation electrostatic storage ring for cryogenic temperatures is under development. The main focus of this unique machine is the research on ions, molecules and clusters up to bio molecules in the energy range of 20-300 keV at low temperatures down to 2 Kelvin. The achievement of this low temperature for all material walls seen by the ions in the storage ring will allow novel experiments to be performed, such as rotational and vibrational state control of molecular ions and their interaction with ultra-low energy electrons and laser radiation. The low temperature of the storage ring not only causes a strong reduction of black body radiation incident onto the stored particles, but also acts as a large cryopump, expected to lead to a vacuum in the 10-15 mbar range. In this paper the cryogenic concept of the storage ring and the related vacuum design will be presented

  20. High energy physics problems

    International Nuclear Information System (INIS)

    Arbuzov, B.A.

    1977-01-01

    Described are modern views on the particle structure and particle interactions at high energies. According to the latest data recieved, all particles can be classified in three groups: 1) strong interacting hadrons; 2) leptons, having no strong interactions; 3) photon. The particle structure is described in a quark model, and with the use of gluons. The elementary particle theory is based on the quantum field theory. The energy increase of interacting particles enables to check the main theory principles, such as conventions for causality, relativistic invariance and unitarity. Investigations of weak interactions are of great importance. The progress in this field is connected with unified gauge theories of weak and electromagnetic interactions. For weak interactions promissing are the experiments with colliding electron-proton rings. The new data, especially at higher energies, will lead to a further refinement of the nature of particles and their interactions

  1. From accelerators to storage rings to

    International Nuclear Information System (INIS)

    Panofsky, W.K.H.

    1983-02-01

    This talk gives a general but highly subjective overview of the expectation for accelerators and colliders for high energy physics, but not extended developments of accelerators and storage rings for application to nuclear structure physics, synchrotron radiation, medical applications or industrial use

  2. Ring energy selection and extra long straight sections for the Advanced Photon Source

    International Nuclear Information System (INIS)

    1987-04-01

    Recommended criteria are given for the performance of Advanced Photon Source (APS), taking into consideration undulator tunability criteria and their relationship to the storage ring energy and undulator gap, length of straight sections

  3. Development of RF-linac and storage ring system for high-current experiments at GSI

    International Nuclear Information System (INIS)

    Hofmann, I.

    1986-08-01

    The heavy ion facility under construction at GSI is suitable for the generation of high-current beams. It consists of a new high-current injector into the Unilac and a synchrotron and storage ring. We discuss the capability of this system to produce short pulses of heavy ions with a specific energy of the order of 0.1 MJ/g. Under these conditions the system allows to perform a first generation of heavy ion driven target experiments and to test most of the critical issues of a large scale heavy ion fusion driver facility. (orig.)

  4. Energy transfer between energetic ring current H(+) and O(+) by electromagnetic ion cyclotron waves

    Science.gov (United States)

    Thorne, Richard M.; Horne, Richard B.

    1994-01-01

    Electromagnetic ion cyclotron (EMIC) waves in the frequency range below the helium gyrofrequency can be excited in the equatorial region of the outer magnetosphere by cyclotron resonant instability with anisotropic ring current H(+) ions. As the unducted waves propagate to higher latitudes, the wave normal should become highly inclined to the ambient magnetic field. Under such conditions, wave energy can be absorbed by cyclotron resonant interactions with ambient O(+), leading to ion heating perpendicular to the ambient magnetic field. Resonant wave absorption peaks in the vicinity of the bi-ion frequency and the second harmonic of the O(+) gyrofrequrency. This absorption should mainly occur at latitudes between 10 deg and 30 deg along auroral field lines (L is greater than or equal to 7) in the postnoon sector. The concomitant ion heating perpendicular to the ambient magnetic field can contribute to the isotropization and geomagnetic trapping of collapsed O(+) ion conics (or beams) that originate from a low-altitude ionospheric source region. During geomagnetic storms when the O(+) content of the magnetosphere is significantly enhanced, the absorption of EMIC waves should become more efficient, and it may contribute to the observed acceleration of O(+) ions of ionospheric origin up to ring current energies.

  5. Modeling photo-desorption in high current storage rings

    International Nuclear Information System (INIS)

    Barletta, W.A.

    1991-01-01

    High luminosity flavor factories are characterized by high fluxes of synchrotron radiation that lead to thermal management difficulties. The associated photo-desorption from the vacuum chamber walls presents an additional design challenge, providing a vacuum system suitable for maintaining acceptable beam-gas lifetimes and low background levels of scattered radiation in the detector. Achieving acceptable operating pressures (1-10 nTorr) with practical pumping schemes requires the use of materials with low photodesorption efficiency operating in a radiation environment beyond that of existing storage rings. Extrapolating the existing photo-desorption data base to the design requirements of high luminosity colliders requires a physical model of the differential cleaning in the vacuum chamber. The authors present a simple phenomenological model of photodesorption that includes effects of dose dependence and diffuse photon reflection to compute the leveling of gas loads in beamlines of high current storage rings that typify heavy flavor factories. This model is also used to estimate chamber commissioning times

  6. Performance characteristics of CdTe drift ring detector

    Science.gov (United States)

    Alruhaili, A.; Sellin, P. J.; Lohstroh, A.; Veeramani, P.; Kazemi, S.; Veale, M. C.; Sawhney, K. J. S.; Kachkanov, V.

    2014-03-01

    CdTe and CdZnTe material is an excellent candidate for the fabrication of high energy X-ray spectroscopic detectors due to their good quantum efficiency and room temperature operation. The main material limitation is associated with the poor charge transport properties of holes. The motivation of this work is to investigate the performance characteristics of a detector fabricated with a drift ring geometry that is insensitive to the transport of holes. The performance of a prototype Ohmic CdTe drift ring detector fabricated by Acrorad with 3 drift rings is reported; measurements include room temperature current voltage characteristics (IV) and spectroscopic performance. The data shows that the energy resolution of the detector is limited by leakage current which is a combination of bulk and surface leakage currents. The energy resolution was studied as a function of incident X-ray position with an X-ray microbeam at the Diamond Light Source. Different ring biasing schemes were investigated and the results show that by increasing the lateral field (i.e. the bias gradient across the rings) the active area, evaluated by the detected count rate, increased significantly.

  7. Probing the structure of matter with Stanford's new $78 million high-energy accelerator

    International Nuclear Information System (INIS)

    Nolan, G.

    1981-01-01

    The US high-energy physics program recently gained a powerful new experimental tool with the completion of the Positron Electron Project (PEP). PEP is a colliding beam storage ring two kilometres in circumference. Collisions are obtained in the PEP ring by injecting electrons and positrons from SLAC's existing linear accelerator so that they circulate in opposite directions. At 6 points in the ring the beams will collide. PEP will enable collisions to be produced at up to 36 GeV

  8. THE ERL HIGH-ENERGY COOLER FOR RHIC

    International Nuclear Information System (INIS)

    BEN-ZVI, I.

    2006-01-01

    Electron cooling [1] entered a new era with the July 2005 cooling of the Tevatron recycler ring [2] at Fermilab, using γ = 9.5. Considering that the cooling rate decreases as faster than γ 2 and the electron energy forces higher electron currents, new acceleration techniques, high-energy electron cooling presents special challenges to the accelerator scientists and engineers. For example, electron cooling of RHIC at collisions requires electron beam energy up to about 54 MeV at an average current of between 50 to 100 mA and a particularly bright electron beam. The accelerator chosen to generate this electron beam is a superconducting Energy Recovery Linac (ERL) with a superconducting RF gun with a laser-photocathode

  9. BERKELEY: ALS ring

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-06-15

    Everybody at Lawrence Berkeley Laboratory's Center for Beam Physics is pleased with the rapid progress in commissioning LBL's Advanced Light Source (ALS) electron storage ring, the foundation for this third-generation synchrotron radiation facility. Designed for a maximum current of 400 mA, the ALS storage ring reached 407 mA just 24 days after storing the first beam on 16 March. ALS construction as a US Department of Energy (DOE) national user facility to provide high-brightness vacuum ultra-violet and soft x-ray radiation began in October 1987. One technical requirement marking project completion was to accumulate a 50-mA current in the storage ring. The ALS passed this milestone on 24 March, a week ahead of the official deadline. Once injected, the electron beam decays quasi-exponentially primarily because of interactions with residual gas molecules in the storage-ring vacuum chamber. Eventually, when the pressure in the vacuum chamber with beam decreases toward the expected operating level of 1 nano Torr, it will only be necessary to refill the storage ring at intervals of four to eight hours. At present the vacuum is improving rapidly as surfaces are irradiated (scrubbed) by the synchrotron radiation itself. At 100 mA, beam lifetime was about one hour (9 April)

  10. BERKELEY: ALS ring

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Everybody at Lawrence Berkeley Laboratory's Center for Beam Physics is pleased with the rapid progress in commissioning LBL's Advanced Light Source (ALS) electron storage ring, the foundation for this third-generation synchrotron radiation facility. Designed for a maximum current of 400 mA, the ALS storage ring reached 407 mA just 24 days after storing the first beam on 16 March. ALS construction as a US Department of Energy (DOE) national user facility to provide high-brightness vacuum ultra-violet and soft x-ray radiation began in October 1987. One technical requirement marking project completion was to accumulate a 50-mA current in the storage ring. The ALS passed this milestone on 24 March, a week ahead of the official deadline. Once injected, the electron beam decays quasi-exponentially primarily because of interactions with residual gas molecules in the storage-ring vacuum chamber. Eventually, when the pressure in the vacuum chamber with beam decreases toward the expected operating level of 1 nano Torr, it will only be necessary to refill the storage ring at intervals of four to eight hours. At present the vacuum is improving rapidly as surfaces are irradiated (scrubbed) by the synchrotron radiation itself. At 100 mA, beam lifetime was about one hour (9 April)

  11. Cooler Storage Ring at China Institute of Modern Physics

    CERN Document Server

    Wen-Xia, Jia; Zhan, W

    2005-01-01

    CSR, a new ion cooler-storage-ring project in China IMP, is a double ring system, and consists of a main ring (CSRm) and an experimental ring (CSRe). The two existing cyclotrons SFC (K=69) and SSC (K=450) of the Heavy Ion Research Facility in Lanzhou (HIRFL) will be used as its injector system. The heavy ion beams with the energy range of 7-30 MeV/nucleus from the HIRFL will be accumulated, cooled and accelerated to the higher energy range of 100-500 MeV/ nucleus in CSRm, and then extracted fast to produce radioactive ion beams or highly charged heavy ions. Those secondary beams will be accepted and stored or decelerated by CSRe for many internal-target experiments or high precision spectroscopy with beam cooling. On the other hand, the beams with the energy range of 100-1000MeV/ nucleus will also be extracted from CSRm by using slow extraction or fast extraction for many external-target experiments. CSR project was started in the end of 1999 and will be finished in 2006. In this paper the outline and the act...

  12. Vacuum system of the high energy ring of an asymmetric B-factory based on PEP

    International Nuclear Information System (INIS)

    Barletta, W.A.; Calderon, M.O.; Wong, R.; Jenkins, T.M.

    1991-01-01

    The multi-ampere currents required for high luminosity operation of an asymmetric B factory leads to extremely stressing requirements on a vacuum system suitable for maintaining long beam-gas lifetimes and acceptable background levels in the detector. We present the design for a Cu alloy vacuum chamber and its associated pumping system for the 9 GeV electron storage ring of the proposed B factory based on PEP. The excellent thermal and photo-desorption properties of Cu allows handling the high proton flux in a conventional, single chamber design with distributed ion pumps. The x-ray opacity of the Cu is sufficiently high that no additional lead shielding is necessary to protect the dipoles from the intense synchrotron radiation generated by the beam. The design allows chamber commissioning in <500 hr of operation. 5 refs., 3 figs., 2 tabs

  13. The Abort Kicker System for the PEP-II Storage Rings at SLAC.

    CERN Document Server

    Delamare, J E

    2003-01-01

    The PEP-II project has two storage rings. The HER (High Energy Ring) has up to 1.48 A of election beam at 9 GeV, and the LER (Low Energy Ring) has up to 2.14 A of positron beam at 3.1 GeV. To protect the HER and LER beam lines in the event of a ring component failure, each ring has an abort kicker system which directs the beam into a dump when a failure is detected. Due to the high current of the beams, the beam kick is tapered from 100% to 80% in 7.33 (micro)S (the beam transit time around the ring). This taper distributes the energy evenly across the window which separates the ring from the beam dump such that the window is not damaged. The abort kicker trigger is synchronized with the ion clearing gap of the beam allowing for the kicker field to rise from 0-80% while there is no beam in the kicker magnet. Originally the kicker system was designed for a rise time of 370nS [1], but because the ion clearing gap was reduced in half, so was the rise time requirement for the kicker. This report discusses the des...

  14. Space charge and working point studies in the CERN Low Energy Ion Ring

    CERN Document Server

    Huschauer, A; Hancock, S; Kain, V

    2017-01-01

    The Low Energy Ion Ring (LEIR) is at the heart ofCERN’s heavy ion physics programme and was designed toprovide the high phase space densities required by the exper-iments at the Large Hadron Collider (LHC). LEIR is the firstsynchrotron of the LHC ion injector chain and it receives aquasi-continuous pulse of lead ions (Pb54+) from Linac3, ex-ploiting a sophisticated multi-turn injection scheme in bothtransverse and longitudinal planes. Seven of these pulses areinjected and accumulated, which requires continuous elec-tron cooling (EC) at low energy to decrease the phase spacevolume of the circulating beam in between two injections.Subsequently, the coasting beam is adiabatically capturedin two bunches, which are then accelerated and extractedtowards the Proton Synchrotron (PS). Figure 1 shows theLEIR magnetic cycle and the different steps required forbeam production.

  15. Reduction of ring artefacts in high resolution micro-CT reconstructions

    International Nuclear Information System (INIS)

    Sijbers, Jan; Postnov, Andrei

    2004-01-01

    High resolution micro-CT images are often corrupted by ring artefacts, prohibiting quantitative analysis and hampering post processing. Removing or at least significantly reducing such artefacts is indispensable. However, since micro-CT systems are pushed to the extremes in the quest for the ultimate spatial resolution, ring artefacts can hardly be avoided. Moreover, as opposed to clinical CT systems, conventional correction schemes such as flat-field correction do not lead to satisfactory results. Therefore, in this note a simple but efficient and fast post processing method is proposed that effectively reduces ring artefacts in reconstructed μ-CT images. (note)

  16. Role of guard rings in improving the performance of silicon detectors

    Indian Academy of Sciences (India)

    number of free charge carriers thus produced is proportional to the energy deposited. 259 .... grounding the innermost guard ring of a strip detector of geometry 60 × 60 mm2. ... The guard ring was kept floating with no electrical connection .... ment of maintaining high-quality semiconductor properties during high temperature.

  17. Fermilab Recycler Ring: Technical design report. Revision 1.1

    International Nuclear Information System (INIS)

    Jackson, G.

    1996-07-01

    This report describes the technical design of the Fermilab Recycler Ring. The purpose of the Recycler is to augment the luminosity increase anticipated from the implementation of the Fermi III upgrade project, which has as its main component the Fermilab Main Injector construction project. The Recycler is a fixed 8 GeV kinetic energy storage ring. It is located in the Main Injector tunnel directly above the Main Injector beamline, near the ceiling. The construction schedule calls for the installation of the Recycler ring before the installation shutdown of the Main Injector. This aggressive construction schedule is made possible by the exclusive use of permanent magnets in the ring lattice, removing the need for expensive conventional iron/copper magnet construction along with the related power supplies, cooling water system, and electrical safety systems. The location, operating energy, and mode of construction are chosen to minimize operational impacts on both Fermilab's ongoing High Energy Physics program and the Main Injector construction project

  18. Ring current energy injection rate and solar wind-magnetosphere energy coupling

    International Nuclear Information System (INIS)

    Lee, L.C.; Kan, J.R.; Akasofu, S.-I.

    1982-01-01

    The purpose of this paper is to (i) formulate the ring current injection rate Usub(R) in terms of phisub(CT) (cross-tail potential drop) by assuming that the ring current formation is a direct consequence of an enhanced convection, (ii) examine the relationship between the injection rate Usub(R) and the power transferred from the solar wind to the magnetosphere and (iii) demonstrate that an enhanced convection indeed leads to the formation of the ring current. (author)

  19. Energy transfer, orbital angular momentum, and discrete current in a double-ring fiber array

    International Nuclear Information System (INIS)

    Alexeyev, C. N.; Volyar, A. V.; Yavorsky, M. A.

    2011-01-01

    We study energy transfer and orbital angular momentum of supermodes in a double-ring array of evanescently coupled monomode optical fibers. The structure of supermodes and the spectra of their propagation constants are obtained. The geometrical parameters of the array, at which the energy is mostly confined within the layers, are determined. The developed method for finding the supermodes of concentric arrays is generalized for the case of multiring arrays. The orbital angular momentum carried by a supermode of a double-ring array is calculated. The discrete lattice current is introduced. It is shown that the sum of discrete currents over the array is a conserved quantity. The connection of the total discrete current with orbital angular momentum of discrete optical vortices is made.

  20. Energy transfer, orbital angular momentum, and discrete current in a double-ring fiber array

    Energy Technology Data Exchange (ETDEWEB)

    Alexeyev, C. N.; Volyar, A. V. [Taurida National V.I. Vernadsky University, Vernadsky Prospekt, 4, Simferopol, 95007, Crimea (Ukraine); Yavorsky, M. A. [Taurida National V.I. Vernadsky University, Vernadsky Prospekt, 4, Simferopol, 95007, Crimea (Ukraine); Universite Bordeaux and CNRS, LOMA, UMR 5798, FR-33400 Talence (France)

    2011-12-15

    We study energy transfer and orbital angular momentum of supermodes in a double-ring array of evanescently coupled monomode optical fibers. The structure of supermodes and the spectra of their propagation constants are obtained. The geometrical parameters of the array, at which the energy is mostly confined within the layers, are determined. The developed method for finding the supermodes of concentric arrays is generalized for the case of multiring arrays. The orbital angular momentum carried by a supermode of a double-ring array is calculated. The discrete lattice current is introduced. It is shown that the sum of discrete currents over the array is a conserved quantity. The connection of the total discrete current with orbital angular momentum of discrete optical vortices is made.

  1. TESTING THE HYPOTHESIS THAT METHANOL MASER RINGS TRACE CIRCUMSTELLAR DISKS: HIGH-RESOLUTION NEAR-INFRARED AND MID-INFRARED IMAGING

    International Nuclear Information System (INIS)

    De Buizer, James M.; Bartkiewicz, Anna; Szymczak, Marian

    2012-01-01

    Milliarcsecond very long baseline interferometry maps of regions containing 6.7 GHz methanol maser emission have lead to the recent discovery of ring-like distributions of maser spots and the plausible hypothesis that they may be tracing circumstellar disks around forming high-mass stars. We aimed to test this hypothesis by imaging these regions in the near- and mid-infrared at high spatial resolution and compare the observed emission to the expected infrared morphologies as inferred from the geometries of the maser rings. In the near-infrared we used the Gemini North adaptive optics system of ALTAIR/NIRI, while in the mid-infrared we used the combination of the Gemini South instrument T-ReCS and super-resolution techniques. Resultant images had a resolution of ∼150 mas in both the near-infrared and mid-infrared. We discuss the expected distribution of circumstellar material around young and massive accreting (proto)stars and what infrared emission geometries would be expected for the different maser ring orientations under the assumption that the masers are coming from within circumstellar disks. Based upon the observed infrared emission geometries for the four targets in our sample and the results of spectral energy distribution modeling of the massive young stellar objects associated with the maser rings, we do not find compelling evidence in support of the hypothesis that methanol masers rings reside in circumstellar disks.

  2. The CERN intersecting storage rings and strong interactions at high energies

    CERN Document Server

    Cocconi, Giuseppe

    1973-01-01

    The coming into operation of the Intersecting Storage Rings (ISR) at the European Centre of Nuclear Research (CERN), near Geneva, has made it possible in the past two years to study the behaviour of matter at the highest densities ever obtained artificially, hundreds of times greater than the density of matter in nuclei and even in the densest stars. An account is given of some of the results obtained thus far; this is followed by a brief discussion of possible future developments. (17 refs).

  3. Water-Energy-Food Nexus in Asia-Pacific Ring of Fire

    Science.gov (United States)

    Taniguchi, M.; Endo, A.; Gurdak, J. J.; Allen, D. M.; Siringan, F.; Delinom, R.; Shoji, J.; Fujii, M.; Baba, K.

    2013-12-01

    Climate change and economic development are causing increased pressure on water, energy and food resources, presenting communities with increased levels of tradeoffs and potential conflicts among these resources. Therefore, the water-energy-food nexus is one of the most important and fundamental global environmental issues facing the world. For the purposes of this research project, we define human-environmental security as the joint optimization between human and environmental security as well as the water-energy-food nexus. To optimize the governance and management within these inter-connected needs, it is desirable to increase human-environmental security by improving social managements for the water-energy-food nexus. In this research project, we intend to establish a method to manage and optimize the human-environmental security of the water-energy-food nexus by using integrated models, indices, and maps as well as social and natural investigations with stakeholder analyses. We base our approach on the viewpoint that it is important for a sustainable society to increase human-environmental security with decreasing risk and increasing resilience by optimizing the connections within the critical water-energy and water-food clusters. We will take a regional perspective to address these global environmental problems. The geological and geomorphological conditions in our proposed study area are heavily influenced by the so-called 'Ring of Fire,' around the Pacific Ocean. Within these areas including Japan and Southeast Asia, the hydro-meteorological conditions are dominated by the Asia monsoon. The populations that live under these natural conditions face elevated risk and potential disaster as negative impacts, while also benefitting from positive ecological goods and services. There are therefore tradeoffs and conflicts within the water-energy-food nexus, as well as among various stakeholders in the region. The objective of this project is to maximize human

  4. Acceleration of polarized proton in high energy accelerators

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1991-01-01

    In low to medium energy accelerators, betatron tune jumps and vertical orbit harmonic correction methods have been used to overcome the intrinsic and imperfection resonances. At high energy accelerators, snakes are needed to preserve polarization. The author analyzes the effects of snake resonances, snake imperfections, and overlapping resonances on spin depolarization. He discusses also results of recent snake experiments at the IUCF Cooler Ring. The snake can overcome various kinds of spin depolarization resonances. These experiments pointed out further that partial snake can be used to cure the imperfection resonances in low to medium energy accelerators

  5. HISTRAP proposal: heavy-ion storage ring for atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D K; Alton, G D; Datz, S; Dittner, P F; Dowling, D T; Haynes, D L; Hudson, E D; Johnson, J W; Lee, I Y; Lord, R S

    1987-04-01

    HISTRAP, Heavy-Ion Storage Ring for Atomic Physics, is a proposed 46.8-m-circumference synchrotron-cooling-storage ring optimized to accelerate, decelerate, and store beams of highly charge very-heavy ions at energies appropriate for advanced atomic physics research. The ring is designed to allow studies of electron-ion, photon-ion, ion-atom, and ion-ion interactions. An electron cooling system will provide ion beams with small angular divergence and energy spread for precision spectroscopic studies and also is necessary to allow the deceleration of heavy ions to low energies. HISTRAP will have a maximum bending power of 2.0 T m and will be injected with ions from either the existing Holifield Heavy Ion Research Facility 25-MV tandem accelerator or from a dedicated ECR source and 250 keV/nucleon RFQ linac.

  6. Excitonic behavior in self-assembled InAs/GaAs quantum rings in high magnetic fields

    NARCIS (Netherlands)

    Kleemans, N.A.J.M.; Blokland, J.H.; Taboada, A.G.; Genuchten, van H.C.M.; Bozkurt, M.; Fomin, V.M.; Gladilin, V.N.; Granados, D.; Garcia, J.M.; Christianen, P.C.M.; Maan, J.C.; Devreese, J.T.; Koenraad, P.M.

    2009-01-01

    We investigate the exciton energy level structure of a large ensemble of InAs/GaAs quantum rings by photoluminescence spectroscopy in magnetic fields up to 30 T for different excitation densities. The confinement of an electron and a hole in these type I quantum rings along with the Coulomb

  7. TSR: A Storage Ring for HIE-ISOLDE

    CERN Document Server

    Butler, P A; Blaum, K; Grieser, M; Davinson, T; Woods, P J; Flanagan, K; Freeman, S J; Lazarus, I H; Litvinov, Yu A; Raabe, R; Siesling, E; Wenander, F

    2016-01-01

    It is planned to install the heavy-ion, low-energy ring TSR, currently at the Max-Planck-Institute for Nuclear Physics in Heidelberg, at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored, cooled secondary beams that is rich and varied, spanning from studies of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. In addition to experiments performed using beams recirculating within the ring, the cooled beams can be extracted and exploited by external spectrometers for high-precision measurements. The capabilities of the ring facility as well as some physics cases will be presented, together with a brief report on the status of the project.

  8. The free energy of locking a ring: Changing a deoxyribonucleoside to a locked nucleic acid.

    Science.gov (United States)

    Xu, You; Villa, Alessandra; Nilsson, Lennart

    2017-06-05

    Locked nucleic acid (LNA), a modified nucleoside which contains a bridging group across the ribose ring, improves the stability of DNA/RNA duplexes significantly, and therefore is of interest in biotechnology and gene therapy applications. In this study, we investigate the free energy change between LNA and DNA nucleosides. The transformation requires the breaking of the bridging group across the ribose ring, a problematic transformation in free energy calculations. To address this, we have developed a 3-step (easy to implement) and a 1-step protocol (more efficient, but more complicated to setup), for single and dual topologies in classical molecular dynamics simulations, using the Bennett Acceptance Ratio method to calculate the free energy. We validate the approach on the solvation free energy difference for the nucleosides thymidine, cytosine, and 5-methyl-cytosine. © 2017 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc. © 2017 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.

  9. High Isolation Dual-Polarized Patch Antenna with Hybrid Ring Feeding

    Directory of Open Access Journals (Sweden)

    Xian-Jing Lin

    2017-01-01

    Full Text Available This paper presents a hybrid ring feeding dual-polarized patch antenna with high isolation in a wide working band. The proposed antenna consists of a circular radiating patch printed on the upper horizontal substrate, two pairs of Γ shaped strips printed on two vertical substrates, and a hybrid ring feeding network printed on the lower two horizontal substrates. The proposed antenna adopts Γ shape strips coupled feeding structure to achieve a wide operating band. Furthermore, a hybrid ring feeding structure with high isolation in a wide bandwidth, which is firstly proposed, is applied as feeding network. When one port is excited, the feeding network can realize twice the power cancellation. Thus, high ports isolation characteristics can be obtained. A prototype of the proposed antenna is fabricated and measured. Measured results show that the 10 dB reflection coefficient bandwidths of the two ports are both about 38.7%, with port isolation higher than 40 dB through most of the band, and the cross-polarizations are below −24 dB.

  10. Polar lunar power ring: Propulsion energy resource

    Science.gov (United States)

    Galloway, Graham Scott

    1990-01-01

    A ring shaped grid of photovoltaic solar collectors encircling a lunar pole at 80 to 85 degrees latitude is proposed as the primary research, development, and construction goal for an initial lunar base. The polar Lunar Power Ring (LPR) is designed to provide continuous electrical power in ever increasing amounts as collectors are added to the ring grid. The LPR can provide electricity for any purpose indefinitely, barring a meteor strike. The associated rail infrastructure and inherently expandable power levels place the LPR as an ideal tool to power an innovative propulsion research facility or a trans-Jovian fleet. The proposed initial output range is 90 Mw to 90 Gw.

  11. An electrostatic storage ring for low kinetic energy electron collisions

    Energy Technology Data Exchange (ETDEWEB)

    Reddish, T J; Tessier, D R; Sullivan, M R; Thorn, P A [Department of Physics, University of Windsor, Windsor, N9B 3P4 (Canada); Hammond, P; Alderman, A J [School of Physics, CAMSP, University of Western Australia, Perth WA 6009 (Australia); Read, F H [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

    2009-11-01

    The criteria are presented for stable multiple orbits of charged particles in a race-track shaped storage ring and applied to an electrostatic system consisting of two hemispherical deflector analyzers (HDA) connected by two separate sets of cylindrical lenses. The results of charged particle simulations and the formal matrix theory, including aberrations in the energy-dispersive electrostatic 'prisms', are in good agreement with the observed experimental operating conditions for this Electron Recycling Spectrometer (ERS).

  12. Simulations of Bunch Precompression at High Currents in the SLC Damping Rings

    International Nuclear Information System (INIS)

    Bane, K.L.F.; Minty, M.G.; Chao, A.W.

    2011-01-01

    In the Stanford Linear Collider (SLC) each beam, after leaving a damping ring, is compressed in the Ring-to-Linac (RTL) transfer line before entering the linear accelerator. At a bunch population of 4.0 x 10 10 particles, due to the limited energy acceptance of the RTL, approximately 15% of the beam has normally been lost. During the 1996 run, however, to eliminate this loss the bunch was partially precompressed in the damping ring, just before extraction; the beam loss in the RTL was reduced to almost zero. The operation and performance of precompression are presented by Minty et al. (1999). Also given is an analysis which, however, does not include the effects of the longitudinal wakefield on the beam dynamics. In this report we extend that analysis to include these effects.

  13. The Abort Kicker System for the PEP-II Storage Rings at SLAC

    International Nuclear Information System (INIS)

    Delamare, Jeffrey E

    2003-01-01

    The PEP-II project has two storage rings. The HER (High Energy Ring) has up to 1.48 A of election beam at 9 GeV, and the LER (Low Energy Ring) has up to 2.14 A of positron beam at 3.1 GeV. To protect the HER and LER beam lines in the event of a ring component failure, each ring has an abort kicker system which directs the beam into a dump when a failure is detected. Due to the high current of the beams, the beam kick is tapered from 100% to 80% in 7.33 (micro)S (the beam transit time around the ring). This taper distributes the energy evenly across the window which separates the ring from the beam dump such that the window is not damaged. The abort kicker trigger is synchronized with the ion clearing gap of the beam allowing for the kicker field to rise from 0-80% while there is no beam in the kicker magnet. Originally the kicker system was designed for a rise time of 370nS [1], but because the ion clearing gap was reduced in half, so was the rise time requirement for the kicker. This report discusses the design of the system interlocks, diagnostics, and modulator with the modifications necessary to accommodate an ion clearing gap of 185nS

  14. Lattice Design in High-energy Particle Accelerators

    CERN Document Server

    Holzer, B.J.

    2014-01-01

    This lecture gives an introduction into the design of high-energy storage ring lattices. Applying the formalism that has been established in transverse be am optics, the basic principles of the development of a magnet lattice are explained and the characteristics of the resulting magnet structure are discussed. The periodic assembly of a storage ring cell with its boundary conditions concerning stability and scaling of the beam optics parameters is addressed as well as special lattice insertions such as drifts, mini beta sections, dispersion suppressors, etc. In addition to the exact calculations that are indispensable for a rigorous treatment of the matter, scaling rules are shown and simple rules of thumb are included that enable the lattice designer to do the first estimates and get the basic numbers ‘ on the back of an envelope.

  15. High energy trends in e+e- physics

    International Nuclear Information System (INIS)

    Wolf, G.

    1979-07-01

    The author gives a survey about the physical research, which is possible due to high energy e + e - -storage rings. After a short description of the status of PETRA the results for the branching ratio of the total cross section to μ + μ -pair production at e + e - annihilations are presented. Then multiplicities and inclusive particle spectra are discussed. Especially the jet formation is considered. Finally the production of the t quark is discussed. (HSI)

  16. 200 MW S-band traveling wave resonant ring development at IHEP

    Science.gov (United States)

    Zhou, Zu-Sheng; Chi, Yun-Long; Git, Meng-Ping; Pei, Guo-Xi

    2010-03-01

    The resonant-ring is a traveling wave circuit, which is used to produce high peak power with comparatively smaller stored energy. The application to be considered is its use as a high power simulator mainly for testing the klystron ceramic output window, as well as for high power microwave transmission devices. This paper describes the principle of a resonant ring and introduces the structure and property of the newly constructed traveling wave resonant ring at IHEP. Our goal is to produce a 200 MW class resonant ring at 2.856 GHz with a pulse length of 2 μs and repetition rate of 25 Hz. The installation, commissioning and testing of the ring have been completed and a peak power of 200 MW at 3 μs has been achieved. The conditioning results show that all the parameters of the resonant ring reach the design goals.

  17. New and unthinkable ideas in high energy physics

    International Nuclear Information System (INIS)

    Lederman, L.M.

    1975-01-01

    Possible future high energy physics experiments and the required detectors are discussed for colliding proton beams in storage rings. Analyses are given on the topics of: (1) baryon conservation; (2) a new object detector; (3) the search for heavy leptons at ISABELLE; (4) identifying super-massive particles decaying solely into very many hadrons; (5) production of anti-nuclei at ISABELLE; and (6) a metastable neutral particle arm

  18. Lattice design of HISTRAP: Heavy ion storage ring for atomic physics

    International Nuclear Information System (INIS)

    Lee, I.Y.; Martin, J.A.; McGrory, J.B.; Milner, W.T.; Olsen, D.K.; Young, G.R.

    1987-01-01

    HISTRAP, a Heavy-Ion Storage Ring for Atomic Physics, is a proposed 46.8-m-circumference synchrotron-cooling-storage ring optimized to accelerate, cool, decelerate, and store beams of highly charged very-heavy ions at energies appropriate for advanced atomic physics research. This four-fold symmetrical ring has a maximum bending power of 2 Tm. It has achromatic bends and uses quadrupole triplets for focusing

  19. Beam Profile Measurement with Flying Wires at the Fermilab Recycler Ring

    CERN Document Server

    Hu, Martin; Krider, John; Lorman, Eugene; Marchionni, Alberto; Pishchalnikov, Yu M; Pordes, Stephen; Slimmer, David; Wilson, Peter R; Zagel, James

    2005-01-01

    The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with stochastic and electron cooling systems. Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement. The following note describes the system configuration, calibration and resolution of the flying wire system, as well as analysis of the transverse beam profile in the presence of both cooling systems.

  20. On the energy dependence of the relative contributions ionospheric and solar sources of the ring current protons

    International Nuclear Information System (INIS)

    Kovtyukh, A.

    2007-01-01

    The energy dependence of a fraction of ring current protons of i onospheric origin is calculated using the AMPTE/CCE data for a typical magnetic storm (D st = -120 nT). It is shown that at L = 6-7 (L is the Mcllwain parameter) this fraction monotonically decreases from ∼83 to 25-30% with an increase in proton energy from 5 to 315 keV and is 30-40% at energy 40-50 keV corresponding to the maximum of proton energy density at L 6-7. It is evident that the core of the ring current (L = 3.7-4.7) is enriched by solar protons with E∼10-200 keV during storm main phase (the maximum effect is achieved at E∼20-50 keV). (author)

  1. Preliminary Design Study of a Pre-booster Damping Ring for the FCC e+e− Injector

    CERN Document Server

    Etisken, O; Papaphilippou, Y

    2017-01-01

    The aim of the FCC e+e− lepton collider is to collide particles in the energy range 40–175 GeV. The FCC e+e− injector complex needs to produce and transport high-intensity e+e− beams at a fast repetition rate of about 0.1 Hz to top up the collider at its collision energy. A basic parameter set exists for all collider energies, assuming a 10 GeV linac operating with a large number of bunches accumulating in the existing SPS, which serves as pre-accelerator and damping ring before the bunches are transferred to the high-energy booster. The purpose of this study is to provide the conceptual design of an alternative damping and accelerator ring, replacing the SPS in the current scheme. This ring will have an injection energy of around 6 GeV and an extraction energy of around 20 GeV. Apart from establishing the basic ring parameters, the final study will include the optics design and layout, and single particle linear and non-linear dynamics optimization, including magnetic and alignment error tolerances. ...

  2. Storage ring design of the 8 GeV synchrotron radiation facility (SPring-8)

    International Nuclear Information System (INIS)

    Hara, M.; Bc, S.H.; Motonaga, S.

    1990-01-01

    In Japan, RIKEN (Institute of Physical and Chemical Research) and JAERI (Japan Atomic Energy Research Institute) have organized a joint design team and started a design study for an 8 GeV synchrotron radiation X-ray source. This paper outlines the status of the design study for the 8 GeV highly brilliant synchrotron radiation X-ray source ring named Super Photon Ring (SPring-8). The facility consists of a main storage ring, a full-energy injector booster synchrotron and a pre-injector 1 GeV linac. The injector linac and synchrotron are laid outside the storage ring because to permit the use of the linac and synchrotron not only as an injector but also as an electron or positron beam source. The purpose of the facility is to provide stable photon beams with high brilliance in the X-ray region. The energy of the stored electrons (positrons) is fixed at 8 GeV to fulfill the required condition using conventional type insertion devices. (N.K.)

  3. Magnetic forces and localized resonances in electron transfer through quantum rings.

    Science.gov (United States)

    Poniedziałek, M R; Szafran, B

    2010-11-24

    We study the current flow through semiconductor quantum rings. In high magnetic fields the current is usually injected into the arm of the ring preferred by classical magnetic forces. However, for narrow magnetic field intervals that appear periodically on the magnetic field scale the current is injected into the other arm of the ring. We indicate that the appearance of the anomalous-non-classical-current circulation results from Fano interference involving localized resonant states. The identification of the Fano interference is based on the comparison of the solution of the scattering problem with the results of the stabilization method. The latter employs the bound-state type calculations and allows us to extract both the energy of metastable states localized within the ring and the width of resonances by analysis of the energy spectrum of a finite size system as a function of its length. The Fano resonances involving states of anomalous current circulation become extremely narrow on both the magnetic field and energy scales. This is consistent with the orientation of the Lorentz force that tends to keep the electron within the ring and thus increases the lifetime of the electron localization within the ring. Absence of periodic Fano resonances in electron transfer probability through a quantum ring containing an elastic scatterer is also explained.

  4. Mapping Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, L. J.; Edgington, S. G.; Pilorz, S. H.; Deau, E.

    2010-10-01

    Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and quick temperature responses are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid, coherent particles can be expected to have higher thermal inertias (Ferrari et al. 2005). Cassini's Composite Infrared Spectrometer has recorded millions of spectra of Saturn's rings since its arrival at Saturn in 2004 (personal communication, M. Segura). CIRS records far infrared radiation between 10 and 600 cm-1 (16.7 and 1000 µm) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn's rings peaks in this wavelength range. FP1 spectra can be used to infer ring temperatures. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The thermal budget of the rings is dominated by the solar radiation absorbed by its constituent particles. When ring particles enter Saturn's shadow this source of energy is abruptly cut off. As a result, ring particles cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  5. External electric field effect on the binding energy of a hydrogenic donor impurity in InGaAsP/InP concentric double quantum rings

    Science.gov (United States)

    Hu, Min; Wang, Hailong; Gong, Qian; Wang, Shumin

    2018-04-01

    Within the framework of effective-mass envelope-function theory, the ground state binding energy of a hydrogenic donor impurity is calculated in the InGaAsP/InP concentric double quantum rings (CDQRs) using the plane wave method. The effects of geometry, impurity position, external electric field and alloy composition on binding energy are considered. It is shown that the peak value of the binding energy appears in two rings with large gap as the donor impurity moves along the radial direction. The binding energy reaches the peak value at the center of ring height when the donor impurity moves along the axial direction. The binding energy shows nonlinear variation with the increase of ring height. With the external electric field applied along the z-axis, the binding energy of the donor impurity located at zi ≥ 0 decreases while that located at zi < 0 increases. In addition, the binding energy decreases with increasing Ga composition, but increases with the increasing As composition.

  6. Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings

    OpenAIRE

    Schippers, Stefan

    2008-01-01

    Dielectronic recombination (DR) of few-electron ions has evolved into a sensitive spectroscopic tool for highly charged ions. This is due to technological advances in electron-beam preparation and ion-beam cooling techniques at heavy-ion storage rings. Recent experiments prove unambiguously that DR collision spectroscopy has become sensitive to 2nd order QED and to nuclear effects. This review discusses the most recent developments in high-resolution spectroscopy of low-energy DR resonances, ...

  7. Report of the eRHIC Ring-Ring Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Aschenauer, E. C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Berg, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brennan, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fedotov, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Litvinenko, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Palmer, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Parker, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Peggs, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ptitsyn, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tepikian, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Willeke, F. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-10-13

    This report evaluates the ring-ring option for eRHIC as a lower risk alternative to the linac-ring option. The reduced risk goes along with a reduced initial luminosity performance. However, a luminosity upgrade path is kept open. This upgrade path consists of two branches, with the ultimate upgrade being either a ring-ring or a linac-ring scheme. The linac-ring upgrade could be almost identical to the proposed linac-ring scheme, which is based on an ERL in the RHIC tunnel. This linac-ring version has been studied in great detail over the past ten years, and its significant risks are known. On the other hand, no detailed work on an ultimate performance ring-ring scenario has been performed yet, other than the development of a consistent parameter set. Pursuing the ring-ring upgrade path introduces high risks and requires significant design work that is beyond the scope of this report.

  8. Complete snake and rotator schemes for spin polarization in proton rings and large electron rings

    International Nuclear Information System (INIS)

    Steffen, K.

    1983-11-01

    In order to maintain spin polarization in proton rings and large electron rings, some generalized Siberian Snake scheme may be required to make the spin tune almost independent of energy and thus avoid depolarizing resonances. The practical problem of finding such schemes that, at reasonable technical effort, can be made to work over large energy ranges has been addressed before and is here revisited in a broadened view and with added new suggestions. As a result, possibly optimum schemes for electron rings (LEP) and proton rings are described. In the proposed LEP scheme, spin rotation is devised such that, at the interaction points, the spin direction is longitudinal as required for experiments. (orig.)

  9. Characteristics of GaAs MESFET inverters exposed to high energy neutrons

    International Nuclear Information System (INIS)

    Bloss, W.L.; Yamada, W.E.; Young, A.M.; Janousek, B.K.

    1988-01-01

    GaAs MESFET circuits have been exposed to high energy neutrons with fluences ranging from 1x10/sup 14/ n/cm/sup 2/ to 2x10/sup 15/ m/cm/sup 2/. Discrete transistors, inverters, and ring oscillators were characterized at each fluence. While the MESFETs exhibit significant threshold voltage shifts and transconductance and saturation current degradation over this range of neutron fluences, the authors have observed improvement in the DC characteristics of Schottky Diode FET Logic (SDFL) inverters. This unusual result has been successfully simulated using device parameters extracted from FETs damaged by exposure to high energy neutrons. Although the decrease in device transconductance results in an increase in inverter gate delay, as reflected in ring oscillator frequency measurements, the authors conclude that GaAs ICs fabricated from this logic family will remain functional after exposure to extreme neutron fluences. This is a consequence of the observed improvement in inverter noise margin evident in both measured and simulated circuit performance

  10. THE POTENTIAL FOR NEUTRINO PHYSICS AT MUON COLLIDERS AND DEDICATED HIGH CURRENT MUON STORAGE RINGS

    International Nuclear Information System (INIS)

    BIGI, I.; BOLTON, T.; FORMAGGIO, J.; HARRIS, D.; MORFIN, J.; SPENTZOURIS, P.; YU, J.; KAYSER, B.; KING, B.J.; MCFARLAND, K.; PETROV, A.; SCHELLMAN, H.; VELASCO, M.; SHROCK, R.

    2000-01-01

    Conceptual design studies are underway for both muon colliders and high-current non-colliding muon storage rings that have the potential to become the first true neutrino factories. Muon decays in long straight sections of the storage rings would produce uniquely intense and precisely characterized two-component neutrino beams--muon neutrinos plus electron antineutrinos from negative muon decays and electron neutrinos plus muon antineutrinos from positive muons. This article presents a long-term overview of the prospects for these facilities to greatly extend the capabilities for accelerator-based neutrino physics studies for both high rate and long baseline neutrino experiments. As the first major physics topic, recent experimental results involving neutrino oscillations have motivated a vigorous design effort towards dedicated neutrino factories that would store muon beams of energies 50 GeV or below. These facilities hold the promise of neutrino oscillation experiments with baselines up to intercontinental distances and utilizing well understood beams that contain, for the first time, a substantial component of multi-GeV electron-flavored neutrinos. In deference to the active and fast-moving nature of neutrino oscillation studies, the discussion of long baseline physics at neutrino factories has been limited to a concise general overview of the relevant theory, detector technologies, beam properties, experimental goals and potential physics capabilities. The remainder of the article is devoted to the complementary high rate neutrino experiments that would study neutrino-nucleon and neutrino-electron scattering and would be performed at high performance detectors placed as close as is practical to the neutrino production straight section of muon storage rings in order to exploit beams with transverse dimensions as small as a few tens of centimeters

  11. THE POTENTIAL FOR NEUTRINO PHYSICS AT MUON COLLIDERS AND DEDICATED HIGH CURRENT MUON STORAGE RINGS

    Energy Technology Data Exchange (ETDEWEB)

    BIGI,I.; BOLTON,T.; FORMAGGIO,J.; HARRIS,D.; MORFIN,J.; SPENTZOURIS,P.; YU,J.; KAYSER,B.; KING,B.J.; MCFARLAND,K.; PETROV,A.; SCHELLMAN,H.; VELASCO,M.; SHROCK,R.

    2000-05-11

    Conceptual design studies are underway for both muon colliders and high-current non-colliding muon storage rings that have the potential to become the first true neutrino factories. Muon decays in long straight sections of the storage rings would produce uniquely intense and precisely characterized two-component neutrino beams--muon neutrinos plus electron antineutrinos from negative muon decays and electron neutrinos plus muon antineutrinos from positive muons. This article presents a long-term overview of the prospects for these facilities to greatly extend the capabilities for accelerator-based neutrino physics studies for both high rate and long baseline neutrino experiments. As the first major physics topic, recent experimental results involving neutrino oscillations have motivated a vigorous design effort towards dedicated neutrino factories that would store muon beams of energies 50 GeV or below. These facilities hold the promise of neutrino oscillation experiments with baselines up to intercontinental distances and utilizing well understood beams that contain, for the first time, a substantial component of multi-GeV electron-flavored neutrinos. In deference to the active and fast-moving nature of neutrino oscillation studies, the discussion of long baseline physics at neutrino factories has been limited to a concise general overview of the relevant theory, detector technologies, beam properties, experimental goals and potential physics capabilities. The remainder of the article is devoted to the complementary high rate neutrino experiments that would study neutrino-nucleon and neutrino-electron scattering and would be performed at high performance detectors placed as close as is practical to the neutrino production straight section of muon storage rings in order to exploit beams with transverse dimensions as small as a few tens of centimeters.

  12. Experimental investigation of the trapping and energy loss mechanisms of intense relativistic electron rings in hydrogen gas and plasma

    International Nuclear Information System (INIS)

    Smith, A.C. Jr.

    1977-01-01

    The results of an experimental study on the trapping and energy loss mechanisms of intense, relativistic electron rings confined in Astron-like magnetic field geometries are presented. The work is subdivided into four sections: gas trapping; average ring electron energetics; plasma trapping, and hollow-beam cusp-injection into gas and plasma. The mechanisms by which the injected beam coalesces into a current ring in the existing Cornell RECE-Berta facility are considered. To investigate the nature of ring electron energy loss mechanisms following completion of the trapping process, a diagnostic was developed utilizing multi-foil X-ray absorption spectroscopy to analyze the Bremsstrahlung generated by the electrons as they impinge upon a thin tungsten wire target suspended in the circulating current. Finally, a set of preliminary experimental results is presented in which an annular electron beam was passed through a coaxial, non-adiabatic magnetic cusp located at one end of a magnetic mirror well

  13. Studies and calculations of transverse emittance growth in proton storage rings

    International Nuclear Information System (INIS)

    Mane, S.R.; Jackson, G.

    1989-01-01

    When high energy storage rings are used to collide beams of particles and antiparticles for high energy physics experiments, it is important to obtain as high an integrated luminosity as possible. Reduction of integrated luminosity can arise from several factors, in particular from growth of the transverse beam sizes (transverse emittances). We have studied the problem of transverse emittance growth in high energy storage rings caused by random dipole noise kicks to the beam. A theoretical formula for the emittance growth rate is derived, and agreement is obtained with experimental measurements where noise of known amplitude and power spectrum was deliberately injected into the Fermilab Tevatron, to kick the beam randomly. In the experiment, phase noise was introduced into the Tevatron rf system, and the measured dependence of horizontal emittance growth on phase noise amplitude is compared against the theoretically derived response. (orig.)

  14. High duty factor structures for e+e- storage rings

    International Nuclear Information System (INIS)

    Allen, M.A.; Karvonen, L.G.

    1976-01-01

    The next generation e + e - storage rings will need rf systems similar to those required for a continuous-duty linac of over 50 MeV. For the PEP Storage Ring at 18 GeV, it is presently planned to provide a peak accelerating voltage of 77 MV in 18 aluminum accelerating structures, each structure consisting of five slot-coupled cells operating in the π mode. Operating experience with the SPEAR five-cell structure is discussed. Power to each structure is provided by a 125-kW high-efficiency four-cavity klystron. No isolation has been used and the resulting interaction between the accelerating structures, klystrons and the stored beams is discussed

  15. Exploring Sub-Femtosecond Correlated Dynamics with an Ultra-low Energy Electrostatic Storage Ring

    International Nuclear Information System (INIS)

    Welsch, C.P.; Grieser, M.; Dorn, A.; Moshammer, R.; Ullrich, J.

    2005-01-01

    Whereas the three-body Coulomb problem for single excitation and ionization was claimed to be solved in a mathematically correct way during 1999 until 2004 for electron impact on hydrogen and helium, ion-impact ionization still represents a major challenge for theory. Troubling discrepancies have been observed recently in fully differential cross sections (FDCS) for helium single ionization by fast ion impact and even experimental total cross sections are in striking disagreement with the predictions of all state-of-the-art theories for low-energy antiproton collisions. Therefore, within the future Facility for Low-energy Antiproton and Ion Research (FLAIR), it has been proposed to combine state-of-the-art many-particle imaging methods with a novel electrostatic storage ring for slow antiprotons in order to realize single and multiple ionization cross section measurements for antiprotons colliding with atoms, molecules and clusters. Total, as well as any differential cross sections up to FDCS including ionization-excitation reactions are envisaged to become available, serving as benchmark data for theory. Here, the present status of experiments in comparison with theory is presented and the layout of an Ultra-low energy Storage Ring (USR) with its integrated reaction microscope at FLAIR is described

  16. Rotational loss of a ring-shaped flywheel supported by high Tc superconducting levitation

    International Nuclear Information System (INIS)

    Teshima, Hidekazu; Tawara, Taichi; Shimada, Ryuichi.

    1997-01-01

    This paper describes the experimental results for the rotational loss of a ring-shaped flywheel supported by high T c superconducting levitation. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub because it is a non-contact and automatically stable levitation without any control systems. The rotational loss has been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The rotational loss decreased as the levitation gap height increased. In low-speed rotational regions, the rotational loss was in proportion to the rotation speed and depended more on the levitation gap. In high-speed rotational regions, the rotational loss was in proportion to the third power of the rotation speed and depended less on the levitation gap. The cubic rotational loss in He was reduced to one-fifth of that in air. The magnetic field pinned in bulk superconductors induces a loss in the materials composing the ring-shaped flywheel. The rotational loss of a ring-shaped flywheel supported by superconducting levitation can be reduced by improving the uniformity of the magnetic fields along the ring, enlargement of the bulk superconductor(s), and densely arranging the bulk superconductors. (author)

  17. NEUTRINO FACTORY BASED ON MUON-STORAGE-RINGS TO MUON COLLIDERS: PHYSICS AND FACILITIES

    International Nuclear Information System (INIS)

    PARSA, Z.

    2001-01-01

    Intense muon sources for the purpose of providing intense high energy neutrino beams (ν factory) represents very interesting possibilities. If successful, such efforts would significantly advance the state of muon technology and provides intermediate steps in technologies required for a future high energy muon collider complex. High intensity muon: production, capture, cooling, acceleration and multi-turn muon storage rings are some of the key technology issues that needs more studies and developments, and will briefly be discussed here. A muon collider requires basically the same number of muons as for the muon storage ring neutrino factory, but would require more cooling, and simultaneous capture of both ± μ. We present some physics possibilities, muon storage ring based neutrino facility concept, site specific examples including collaboration feasibility studies, and upgrades to a full collider

  18. NEUTRINO FACTORY BASED ON MUON-STORAGE-RINGS TO MUON COLLIDERS: PHYSICS AND FACILITIES.

    Energy Technology Data Exchange (ETDEWEB)

    PARSA,Z.

    2001-06-18

    Intense muon sources for the purpose of providing intense high energy neutrino beams ({nu} factory) represents very interesting possibilities. If successful, such efforts would significantly advance the state of muon technology and provides intermediate steps in technologies required for a future high energy muon collider complex. High intensity muon: production, capture, cooling, acceleration and multi-turn muon storage rings are some of the key technology issues that needs more studies and developments, and will briefly be discussed here. A muon collider requires basically the same number of muons as for the muon storage ring neutrino factory, but would require more cooling, and simultaneous capture of both {+-} {mu}. We present some physics possibilities, muon storage ring based neutrino facility concept, site specific examples including collaboration feasibility studies, and upgrades to a full collider.

  19. High energy synchrotron radiation. A new probe for condensed matter research

    International Nuclear Information System (INIS)

    Schneider, J.R.; Bouchard, R.; Brueckel, T.; Lippert, M.; Neumann, H.B.; Poulsen, H.F.; Ruett, U.; Schmidt, T.; Zimmermann, M. von

    1994-01-01

    The absorption of 150 keV synchrotron radiation in matter is weak and, as normally done with neutrons, bulk properties are studied in large samples. However, the k-space resolution obtained with a Triple Crystal Diffractometer (TCD) for high energy synchrotron radiation is about one order of magnitude better than in high resolution neutron diffraction. The technique has been applied to measure the structure factor S(Q) of amorphous solids up to momentum transfers of the order of 32 A -1 , to study the intermediate range Ortho-II ordering in large, high quality YBa 2 Cu 3 O 6.5 single crystals and for investigations of the defect scattering from annealed Czochralski grown silicon crystals. Magnetic superlattice reflections have been measured in MnF 2 demonstrating the potential of the technique for high resolution studies of ground state bulk antiferromagnetism. Recently the question of two length scales in the critical scattering at the 100 K phase transition in SrTiO 3 was studied. At the PETRA storage ring, which serves as an accumulator for the HERA electron-proton-ring at DESY and which can be operated up to electron energies of 12 GeV, an undulator beam line is currently under construction and should be available in summer 1995. It opens up exciting new research opportunities for photon energies from about 20 to 150 keV. (orig.)

  20. Radial transport of high-energy oxygen ions into the deep inner magnetosphere observed by Van Allen Probes

    Science.gov (United States)

    Mitani, K.; Seki, K.; Keika, K.; Gkioulidou, M.; Lanzerotti, L. J.; Mitchell, D. G.; Kletzing, C.

    2017-12-01

    It is known that proton is main contributor of the ring current and oxygen ions can make significant contribution during major magnetic storms. Ions are supplied to the ring current by radial transport from the plasma sheet. Convective transport of lower-energy protons and diffusive transport of higher-energy protons were reported to contribute to the storm-time and quiet-time ring current respectively [e.g., Gkioulidou et al., 2016]. However, supply mechanisms of the oxygen ions are not clear. To characterize the supply of oxygen ions to the ring current during magnetic storms, we studied the properties of energetic proton and oxygen ion phase space densities (PSDs) for specific magnetic moment (μ) during the April 23-25, 2013, geomagnetic storm observed by the Van Allen Probes mission. We here report on radial transport of high-energy (μ ≥ 0.5 keV/nT) oxygen ions into the deep inner magnetosphere during the late main phase of the magnetic storm. Since protons show little change during this period, this oxygen radial transport is inferred to cause the development of the late main phase. Enhancement of poloidal magnetic fluctuations is simultaneously observed. We estimated azimuthal mode number ≤5 by using cross wavelet analysis with ground-based observation of IMAGE ground magnetometers. The fluctuations can resonate with drift and bounce motions of the oxygen ions. The results suggest that combination of the drift and drift-bounce resonances is responsible for the radial transport of high-energy oxygen ions into the deep inner magnetosphere. We also report on the radial transport of the high-energy oxygen ions into the deep inner magnetosphere during other magnetic storms.

  1. Proton storage rings

    International Nuclear Information System (INIS)

    Rau, R.R.

    1978-04-01

    A discussion is given of proton storage ring beam dynamic characteristics. Topics considered include: (1) beam energy; (2) beam luminosity; (3) limits on beam current; (4) beam site; (5) crossing angle; (6) beam--beam interaction; (7) longitudinal instability; (8) effects of scattering processes; (9) beam production; and (10) high magnetic fields. Much of the discussion is related to the design parameters of ISABELLE, a 400 x 400 GeV proton---proton intersecting storage accelerator to be built at Brookhaven National Laboratory

  2. Status report of the Cornell High Energy Synchrotron Radiation Source (CHESS)

    International Nuclear Information System (INIS)

    Batterman, B.W.

    1980-01-01

    The Wilson Laboratory at Cornell University has done pioneering work on the development of high energy synchrotrons. In the last decade the 12 GeV Wilson Synchrotron was the most energetic electron synchrotron in the world. In 1975 plans were formulated at the Wilson Laboratory to build a new electron-positron storage ring to cover the range from 4-8 GeV. The storage ring was to be constructed in the same tunnel as the present synchrotron and to use the latter as an injector for the ring. A novel injection feature was to be incorporated, namely, vernier phase compression. In this scheme, positron coalesence is to be performed by compressing a 30-60 bunch positron beam by tranferring individual bunches from the storage ring to the synchrotron and stacking back into the storage ring. This procedure takes advantage of the slight circumferential difference between the storage ring and the synchrotron. Positron beams of 10 mA have been achieved in CESR at the present time. The first colliding beam studies were performed in an October 1979 two-week running period at which time CHESS, the synchrotron radiation source associated with CESR, also had its first extended experience with synchrotron light. (orig.)

  3. TSR: A storage and cooling ring for HIE-ISOLDE

    Energy Technology Data Exchange (ETDEWEB)

    Butler, P.A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Blaum, K. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Davinson, T. [School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Flanagan, K.; Freeman, S.J. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Grieser, M. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Lazarus, I.H. [S.T.F.C. Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Litvinov, Yu.A. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt (Germany); Lotay, G. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Page, R.D. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Raabe, R. [KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven (Belgium); Siesling, E.; Wenander, F. [CERN, 1211 Geneva 23 (Switzerland); Woods, P.J. [School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)

    2016-06-01

    It is planned to install the heavy-ion, low-energy ring TSR, currently at the Max-Planck-Institute for Nuclear Physics in Heidelberg, at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored, cooled secondary beams that is rich and varied, spanning from studies of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. In addition to experiments performed using beams recirculating within the ring, the cooled beams can be extracted and exploited by external spectrometers for high-precision measurements. The capabilities of the ring facility as well as some physics cases will be presented, together with a brief report on the status of the project.

  4. Artificial light harvesting by dimerized Möbius ring

    Science.gov (United States)

    Xu, Lei; Gong, Z. R.; Tao, Ming-Jie; Ai, Qing

    2018-04-01

    We theoretically study artificial light harvesting by a Möbius ring. When the donors in the ring are dimerized, the energies of the donor ring are split into two subbands. Because of the nontrivial Möbius boundary condition, both the photon and acceptor are coupled to all collective-excitation modes in the donor ring. Therefore, the quantum dynamics in the light harvesting is subtly influenced by dimerization in the Möbius ring. It is discovered that energy transfer is more efficient in a dimerized ring than that in an equally spaced ring. This discovery is also confirmed by a calculation with the perturbation theory, which is equivalent to the Wigner-Weisskopf approximation. Our findings may be beneficial to the optimal design of artificial light harvesting.

  5. Design studies for the electron storage ring EUTERPE

    Energy Technology Data Exchange (ETDEWEB)

    Boling, Xi

    1995-05-18

    The 400 MeV electron storage ring EUTERPE is under construction at Eindhoven University of Technology. The ring is to be used as an experimental tool for accelerator physics studies and synchroton radiation applications. The main task of the current research work is the electron optical design of the ring. Lattice design is a basis for machine design as a whole. Design aspects regarding the basic lattice, based on single particle dynamics, include determination of the equilibrium beam size and bunch length, design of achromatic bending sections, selection of tune values, correction of chromaticity, and minimization of the natural emittance in the ring. The basic lattice designed for the EUTERPE ring has a high flexibility so that different electron optical modes can be realized easily. In low energy storage rings with a high beam current, collective effects can cause a significant change in the bunch length, the transverse emittance and the beam lifetime. In order to ensure a good optical performance for the ring, the choice of suitable parameters concerning the vacuum and RF system are essential as far as collective effects are concerned. An estimation of the collective effects in the ring is given. The injector for EUTERPE is a 75 MeV racetrack microtron which is injected from a 10 MeV linac. In order to get sufficient beam current in the ring, a special procedure of continuous injection with an adjustable locally shifted closed orbit has been presented. Details of the injection procedure and numerical simulations are given. (orig./HSI).

  6. Design studies for the electron storage ring EUTERPE

    International Nuclear Information System (INIS)

    Xi Boling.

    1995-01-01

    The 400 MeV electron storage ring EUTERPE is under construction at Eindhoven University of Technology. The ring is to be used as an experimental tool for accelerator physics studies and synchroton radiation applications. The main task of the current research work is the electron optical design of the ring. Lattice design is a basis for machine design as a whole. Design aspects regarding the basic lattice, based on single particle dynamics, include determination of the equilibrium beam size and bunch length, design of achromatic bending sections, selection of tune values, correction of chromaticity, and minimization of the natural emittance in the ring. The basic lattice designed for the EUTERPE ring has a high flexibility so that different electron optical modes can be realized easily. In low energy storage rings with a high beam current, collective effects can cause a significant change in the bunch length, the transverse emittance and the beam lifetime. In order to ensure a good optical performance for the ring, the choice of suitable parameters concerning the vacuum and RF system are essential as far as collective effects are concerned. An estimation of the collective effects in the ring is given. The injector for EUTERPE is a 75 MeV racetrack microtron which is injected from a 10 MeV linac. In order to get sufficient beam current in the ring, a special procedure of continuous injection with an adjustable locally shifted closed orbit has been presented. Details of the injection procedure and numerical simulations are given. (orig./HSI)

  7. Performance of a Polarized Deuterium Internal Target in a Medium-Energy Electron Storage Ring.

    NARCIS (Netherlands)

    Zhou, Z.L.; Ferro Luzzi, M.M.E.; van den Brand, J.F.J.; Bulten, H.J.; Alarcon, R.; van Bommel, R.; Botto, T.; Bouwhuis, M.; Buchholz, M.; Choi, S.; Comfort, J.; Doets, M.; Dolfini, S.; Ent, R.; Gaulard, C.; de Jager, C.W.; Lang, J.; de Lange, D.J.; Miller, M.A.; Passchier, E.; Passchier, I.; Poolman, H.R.; Six, E.; Steijger, J.J.M.; Unal, O.; de Vries, H.

    1996-01-01

    A polarized deuterium target internal to a medium-energy electron storage ring is described in the context of spindependent (e, e′d) and (e ,e′p) experiments. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used

  8. Influence of topology in a quantum ring

    International Nuclear Information System (INIS)

    Netto, A.L. Silva; Chesman, C.; Furtado, C.

    2008-01-01

    In this Letter we study the quantum rings in the presence of a topological defect. We use geometric theory of defects to describe one and two-dimensional quantum rings in the presence of a single screw dislocation. In addition we consider some potential in a two dimensional ring and calculate their energy spectrum. It is shown that the energy spectrum depend on the parabolic way on the burgers vectors of the screw dislocation. We also show that the presence of a topological defect introduces a new contribution for the Aharonov-Bohm effect in the quantum ring

  9. Ringed Accretion Disks: Evolution of Double Toroidal Configurations

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: daniela.pugliese@fpf.slu.cz, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2017-04-01

    We investigate ringed accretion disks composed of two tori (rings) orbiting on the equatorial plane of a central supermassive Kerr black hole. We discuss the emergence of the instability phases of each ring of the macro-configuration (ringed disk) according to the Paczynski violation of mechanical equilibrium. In the full general relativistic treatment, we consider the effects of the geometry of the Kerr spacetimes relevant to the characterization of the evolution of these configurations. The discussion of ring stability in different spacetimes enables us to identify particular classes of central Kerr attractors depending on their dimensionless spin. As a result of this analysis, we set constraints on the evolutionary schemes of the ringed disks relative to the torus morphology and on their rotation relative to the central black hole and to each other. The dynamics of the unstable phases of this system is significant for the high-energy phenomena related to accretion onto supermassive black holes in active galactic nuclei and the extremely energetic phenomena in quasars, which could be observed in their X-ray emission.

  10. Sensitivity Analysis for the CLIC Damping Ring Inductive Adder

    CERN Document Server

    Holma, Janne

    2012-01-01

    The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse generators for the damping ring kickers must provide extremely flat, high-voltage pulses. The specifications for the extraction kickers of the CLIC damping rings are particularly demanding: the flattop of the output pulse must be 160 ns duration, 12.5 kV and 250 A, with a combined ripple and droop of not more than ±0.02 %. An inductive adder allows the use of different modulation techniques and is therefore a very promising approach to meeting the specifications. PSpice has been utilised to carry out a sensitivity analysis of the predicted output pulse to the value of both individual and groups of circuit compon...

  11. ORBIT : BEAM DYNAMICS CALCULATIONS FOR HIGH - INTENSITY RINGS

    International Nuclear Information System (INIS)

    HOLMES, J.A.; DANILOV, V.; GALAMBOS, J.; SHISHLO, A.; COUSINEAU, S.; CHOU, W.; MICHELOTTI, L.; OSTIGUY, F.; WEI, J.

    2002-01-01

    We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK the introduction of a treatment magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings

  12. Thousand TeV in the center of mass: introduction to high-energy storage rings

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1982-09-01

    The lecture discusses, in a pedagogic way, a hypothetical 500 TeV proton storage ring accelerator. It gives machine parameters, discusses linear optics and betatron motions, surveys questions of errors, tolerances and nonlinear resonances, and discusses some of the demands on the detection apparatus, especially the apparent inevitability of multiple interactions per bunch crossing

  13. 1000-TeV in the Center-Of-Mass: Introduction to High-Energy Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Bjorken, J D

    1982-09-01

    The lecture discusses, in a pedagogic way, a hypothetical 500 TeV proton storage ring accelerator. It gives machine parameters, discusses linear optics and betatron motions, surveys questions of errors, tolerances and nonlinear resonances, and discusses some of the demands on the detection apparatus, especially the apparent inevitability of multiple interactions per bunch crossing. (GHT)

  14. Proton accumulator ring injection studies

    International Nuclear Information System (INIS)

    Cooper, R.K.; Neil, V.K.

    1977-01-01

    Protons may be created in an accelerator or storage ring by stripping electrons from neutral hydrogen atoms that have been injected into the machine. Because Liouville's theorem is violated by this type of injection, particles may be continually injected into a region of phase space that is already populated, and the density in that region increases with time. A computational investigation was made of the evolution of the distribution of particles in longitudinal phase space during such an injection process for a storage ring operating below the transition energy. In one calculation, an rf cavity is present in the ring and particles are injected into the stable phase region once each revolution. The purpose of this calculation is to determine the rf voltage necessary to overcome the longitudinal self-forces and contain the particles within the region of stable phase. In a second calculation, the rf is turned off, so that there is spreading in azimuth of the injected particles (i.e., de-bunching). The de-bunching occurs because of the initial energy spread and the action of the self-forces. One purpose of the calculation is to determine the total energy spread after a given number of revolutions. Another purpose is to elucidate the effect of finite resistance in the vacuum tank walls. For sufficiently high current, the finite resistance can cause bunching of a beam that is initially uniform in azimuth. Therefore it might be expected that the finite resistance would inhibit or prevent de-bunching once the number of particles injected reaches some threshold, and that this threshold would depend upon the energy spread in the beam

  15. Radiation safety design for SSRL storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Khater, Hesham [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)]. E-mail: khater1@llnl.gov; Liu, James [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Fasso, Alberto [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Prinz, Alyssa [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Rokni, Sayed [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2006-12-15

    In 2003, the Stanford Synchrotron Radiation Laboratory (SSRL) had upgraded its storage ring to a 3rd generation storage ring (SPEAR3). SPEAR3 is deigned to operate at 500-mA stored beam current and 3-GeV energy. The 234-m circumference SPEAR3 ring utilizes 60-cm-thick concrete lateral walls, 30-cm-thick concrete roof, as well as 60- or 90-cm-thick concrete ratchet walls. A total of 3.5x10{sup 15}e{sup -}/y will be injected into the ring with an injection power of 4W and an injection efficiency of 75%. Normal beam losses occur due to both injection and stored beam operations in the total of 20 low loss as well as 3 high loss limiting apertures. During the 6-min injection period, an instantaneous power loss of 0.05W occurs at each low loss aperture. When averaged over the operational year, the loss of both the injection and the stored beams is equivalent to an average loss of 2mW at each low loss aperture. On the other hand, the average losses in the high loss apertures are 16mW for the injection septum, 47mW for the beam abort dump, and 13mW for the ring stoppers. The shielding requirements for losses in the new ring were based on a generic approach that used both FLUKA Monte Carlo particle generation and transport code and empirical computer codes and formulae.

  16. Energy efficiency improvements utilising mass flow control and a ring topology in a district heating network

    International Nuclear Information System (INIS)

    Laajalehto, Tatu; Kuosa, Maunu; Mäkilä, Tapio; Lampinen, Markku; Lahdelma, Risto

    2014-01-01

    Heating and cooling have a major role in the energy sector, covering 46% of total final energy use worldwide. District heating (DH) is a significant technology for improving the energy efficiency of heating systems in communities, because it enables waste heat sources to be utilised economically and therefore significantly reduces the environmental impacts of power generation. As a result of new and more stringent construction regulations for buildings, the heat demands of individual buildings are decreasing and more energy-efficient heating systems have to be developed. In this study, the energy efficiency of a new DH system which includes both a new control system called mass flow control and a new network design called a ring network is examined. A topology in the Helsinki region is studied by using a commercial DH network modelling tool, Grades Heating. The district heating network is attached to a wood-burning heat station which has a heat recovery system in use. Examination is performed by means of both technical and economic analysis. The new non-linear temperature programme that is required is adopted for supply and return temperatures, which allows greater temperature cooling and smaller flow rates. Lower district heating water temperatures are essential when reducing the heat losses in the network and heat production. Mass flow control allows smaller pressure drops in the network and thus reduces the pumping power. The aim of this study was to determine the most energy-efficient DH water supply temperatures in the case network. If the ring network design is utilised, the district heating system is easier to control. As a result the total heat consumption within the heating season is reduced compared to traditional DH systems. On the basis of the results, the new DH system is significantly more energy-efficient in the case network that was examined than the traditional design. For example, average energy losses within the constraints (which consist of heat

  17. Vortex formation in narrow ferromagnetic rings

    International Nuclear Information System (INIS)

    Klaeui, M; Vaz, C A F; Lopez-Diaz, L; Bland, J A C

    2003-01-01

    The high-symmetry ring geometry is shown to exhibit a wide range of intriguing magnetostatic and magnetodynamic properties, which we survey in this topical review. We consider first the patterning and deposition techniques, which are used to fabricate ring structures (diameters between 0.1 and 2 μm) and discuss their respective advantages and disadvantages. The results of direct nanoscale imaging of the novel magnetization configurations present in rings with different geometrical parameters (including discs) are discussed. These results give valuable insight into the influence of the magnetic anisotropies governing the magnetic states. The different types of domain walls that arise are compared quantitatively to micromagnetic simulations. The magnetodynamic switching between the different magnetic states is described in detail. In particular we elaborate on the different geometry-dependent magnetic switchings, since the different transitions occurring allow us to determine which energy terms govern the reversal process. We discuss a process by which fast (sub-ns) and controlled switching can be achieved, therefore making rings an attractive geometry for applications, in addition to studying fundamental issues of nanomagnetism. (topical review)

  18. Superconducting Magnet Technology for Future High Energy Proton Colliders

    Science.gov (United States)

    Gourlay, Stephen

    2017-01-01

    Interest in high field dipoles has been given a boost by new proposals to build a high-energy proton-proton collider to follow the LHC and programs around the world are taking on the task to answer the need. Studies aiming toward future high-energy proton-proton colliders at the 100 TeV scale are now being organized. The LHC and current cost models are based on technology close to four decades old and point to a broad optimum of operation using dipoles with fields between 5 and 12T when site constraints, either geographical or political, are not a factor. Site geography constraints that limit the ring circumference can drive the required dipole field up to 20T, which is more than a factor of two beyond state-of-the-art. After a brief review of current progress, the talk will describe the challenges facing future development and present a roadmap for moving high field accelerator magnet technology forward. This work was supported by the Director, Office of Science, High Energy Physics, US Department of Energy, under contract No. DE-AC02-05CH11231.

  19. Storage-ring FEL for the vuv

    International Nuclear Information System (INIS)

    Peterson, J.M.; Bisognano, J.J.; Garren, A.A.; Halbach, K.; Kim, K.J.; Sah, R.C.

    1984-09-01

    A free-electron laser for the vuv operating in a storage ring requires an electron beam of high density and low energy spread and a short wavelength, narrow-gap undulator. These conditions tend to produce longitudinal and transverse beam instabilities, excessive beam growth through multiple intrabeam scattering, and a short gas-scattering lifetime. Passing the beam only occasionally through the undulator in a by-pass straight section, as proposed by Murphy and Pellegrini, allows operation in a high-gain, single-pass mode and a long gas-scattering lifetime. Several storage ring designs have been considered to see how best to satisfy the several requirements. Each features a by-pass, a low-emittance lattice, and built-in wigglers for enhanced damping to counteract the intra-beam scattering. 15 references, 3 figures, 2 tables

  20. Multi-state lasing in self-assembled ring-shaped green fluorescent protein microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, Christof P., E-mail: cpd3@st-andrews.ac.uk; Höfling, Sven; Gather, Malte C., E-mail: mcg6@st-andrews.ac.uk [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2014-12-08

    We demonstrate highly efficient lasing from multiple photonic states in microcavities filled with self-assembled rings of recombinant enhanced green fluorescent protein (eGFP) in its solid state form. The lasing regime is achieved at very low excitation energies of 13 nJ and occurs from cavity modes dispersed in both energy and momentum. We attribute the momentum distribution to very efficient scattering of incident light at the surface of the eGFP rings. The distribution of lasing states in energy is induced by the large spectral width of the gain spectrum of recombinant eGFP (FWHM ≅ 25 nm)

  1. Light-Ring Stability for Ultracompact Objects

    Science.gov (United States)

    Cunha, Pedro V. P.; Berti, Emanuele; Herdeiro, Carlos A. R.

    2017-12-01

    We prove the following theorem: axisymmetric, stationary solutions of the Einstein field equations formed from classical gravitational collapse of matter obeying the null energy condition, that are everywhere smooth and ultracompact (i.e., they have a light ring) must have at least two light rings, and one of them is stable. It has been argued that stable light rings generally lead to nonlinear spacetime instabilities. Our result implies that smooth, physically and dynamically reasonable ultracompact objects are not viable as observational alternatives to black holes whenever these instabilities occur on astrophysically short time scales. The proof of the theorem has two parts: (i) We show that light rings always come in pairs, one being a saddle point and the other a local extremum of an effective potential. This result follows from a topological argument based on the Brouwer degree of a continuous map, with no assumptions on the spacetime dynamics, and, hence, it is applicable to any metric gravity theory where photons follow null geodesics. (ii) Assuming Einstein's equations, we show that the extremum is a local minimum of the potential (i.e., a stable light ring) if the energy-momentum tensor satisfies the null energy condition.

  2. High-precision gauging of metal rings

    Science.gov (United States)

    Carlin, Mats; Lillekjendlie, Bjorn

    1994-11-01

    Raufoss AS designs and produces air brake fittings for trucks and buses on the international market. One of the critical components in the fittings is a small, circular metal ring, which is going through 100% dimension control. This article describes a low-price, high accuracy solution developed at SINTEF Instrumentation based on image metrology and a subpixel resolution algorithm. The measurement system consists of a PC-plugg-in transputer video board, a CCD camera, telecentric optics and a machine vision strobe. We describe the measurement technique in some detail, as well as the robust statistical techniques found to be essential in the real life environment.

  3. A stochastic model of depolarization enhancement due to large energy spread in electron storage rings

    International Nuclear Information System (INIS)

    Buon, J.

    1988-10-01

    A new semiclassical and stochastic model of spin diffusion is used to obtain numerical predictions for depolarization enhancement due to beam energy spread. It confirms the results of previous models for the synchrotron sidebands of isolated spin resonances. A satisfactory agreement is obtained with the width of a synchrotron satellite observed at SPEAR. For HERA and LEP, at Z 0 energy, the depolarization enhancement is of the order of a few units and increases very rapidly with the energy spread. Large reduction of polarization degree is expected in these rings

  4. Single-Particle Dynamics in Electron Storage Rings with Extremely Low Emittance

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai; /SLAC

    2011-05-31

    Electron storage rings are widely used for high luminosity colliders, damping rings in high-energy linear colliders, and synchrotron light sources. They have become essential facilities to study high-energy physics and material and medical sciences. To further increase the luminosity of colliders or the brightness of synchrotron light sources, the beam emittance is being continually pushed downward, recently to the nanometer region. In the next decade, another order of reduction is expected. This requirement of ultra-low emittance presents many design challenges in beam dynamics, including better analysis of maps and improvement of dynamic apertures. To meet these challenges, we have refined transfer maps of common elements in storage rings and developed a new method to compute the resonance driving terms as they are built up along a beamline. The method is successfully applied to a design of PEP-X as a future light source with 100-pm emittance. As a result, we discovered many unexpected cancelations of the fourth-order resonance terms driven by sextupoles within an achromat.

  5. Adiabatic compression of ion rings

    International Nuclear Information System (INIS)

    Larrabee, D.A.; Lovelace, R.V.

    1982-01-01

    A study has been made of the compression of collisionless ion rings in an increasing external magnetic field, B/sub e/ = zB/sub e/(t), by numerically implementing a previously developed kinetic theory of ring compression. The theory is general in that there is no limitation on the ring geometry or the compression ratio, lambdaequivalentB/sub e/ (final)/B/sub e/ (initial)> or =1. However, the motion of a single particle in an equilibrium is assumed to be completely characterized by its energy H and canonical angular momentum P/sub theta/ with the absence of a third constant of the motion. The present computational work assumes that plasma currents are negligible, as is appropriate for a low-temperature collisional plasma. For a variety of initial ring geometries and initial distribution functions (having a single value of P/sub theta/), it is found that the parameters for ''fat'', small aspect ratio rings follow general scaling laws over a large range of compression ratios, 1 3 : The ring radius varies as lambda/sup -1/2/; the average single particle energy as lambda/sup 0.72/; the root mean square energy spread as lambda/sup 1.1/; and the total current as lambda/sup 0.79/. The field reversal parameter is found to saturate at values typically between 2 and 3. For large compression ratios the current density is found to ''hollow out''. This hollowing tends to improve the interchange stability of an embedded low β plasma. The implications of these scaling laws for fusion reactor systems are discussed

  6. A high-throughput in vitro ring assay for vasoactivity using magnetic 3D bioprinting

    Science.gov (United States)

    Tseng, Hubert; Gage, Jacob A.; Haisler, William L.; Neeley, Shane K.; Shen, Tsaiwei; Hebel, Chris; Barthlow, Herbert G.; Wagoner, Matthew; Souza, Glauco R.

    2016-01-01

    Vasoactive liabilities are typically assayed using wire myography, which is limited by its high cost and low throughput. To meet the demand for higher throughput in vitro alternatives, this study introduces a magnetic 3D bioprinting-based vasoactivity assay. The principle behind this assay is the magnetic printing of vascular smooth muscle cells into 3D rings that functionally represent blood vessel segments, whose contraction can be altered by vasodilators and vasoconstrictors. A cost-effective imaging modality employing a mobile device is used to capture contraction with high throughput. The goal of this study was to validate ring contraction as a measure of vasoactivity, using a small panel of known vasoactive drugs. In vitro responses of the rings matched outcomes predicted by in vivo pharmacology, and were supported by immunohistochemistry. Altogether, this ring assay robustly models vasoactivity, which could meet the need for higher throughput in vitro alternatives. PMID:27477945

  7. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    International Nuclear Information System (INIS)

    Kovalenko, Oleksandr

    2015-01-01

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U 90+ beam at the existing storage ring ESR, GSI.

  8. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleksandr

    2015-06-24

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U{sup 90+} beam at the existing storage ring ESR, GSI.

  9. The practical Pomeron for high energy proton collimation

    Energy Technology Data Exchange (ETDEWEB)

    Appleby, R.B. [University of Manchester, The Cockcroft Institute, Manchester (United Kingdom); Barlow, R.J.; Toader, A. [The University of Huddersfield, Huddersfield (United Kingdom); Molson, J.G. [Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, LAL, Orsay (France); Serluca, M. [CERN, Geneva (Switzerland)

    2016-10-15

    We present a model which describes proton scattering data from ISR to Tevatron energies, and which can be applied to collimation in high energy accelerators, such as the LHC and FCC. Collimators remove beam halo particles, so that they do not impinge on vulnerable regions of the machine, such as the superconducting magnets and the experimental areas. In simulating the effect of the collimator jaws it is crucial to model the scattering of protons at small momentum transfer t, as these protons can subsequently survive several turns of the ring before being lost. At high energies these soft processes are well described by Pomeron exchange models. We study the behaviour of elastic and single-diffractive dissociation cross sections over a wide range of energy, and show that the model can be used as a global description of the wide variety of high energy elastic and diffractive data presently available. In particular it models low mass diffraction dissociation, where a rich resonance structure is present, and thus predicts the differential and integrated cross sections in the kinematical range appropriate to the LHC. We incorporate the physics of this model into the beam tracking code MERLIN and use it to simulate the resulting loss maps of the beam halo lost in the collimators in the LHC. (orig.)

  10. The practical Pomeron for high energy proton collimation

    Science.gov (United States)

    Appleby, R. B.; Barlow, R. J.; Molson, J. G.; Serluca, M.; Toader, A.

    2016-10-01

    We present a model which describes proton scattering data from ISR to Tevatron energies, and which can be applied to collimation in high energy accelerators, such as the LHC and FCC. Collimators remove beam halo particles, so that they do not impinge on vulnerable regions of the machine, such as the superconducting magnets and the experimental areas. In simulating the effect of the collimator jaws it is crucial to model the scattering of protons at small momentum transfer t, as these protons can subsequently survive several turns of the ring before being lost. At high energies these soft processes are well described by Pomeron exchange models. We study the behaviour of elastic and single-diffractive dissociation cross sections over a wide range of energy, and show that the model can be used as a global description of the wide variety of high energy elastic and diffractive data presently available. In particular it models low mass diffraction dissociation, where a rich resonance structure is present, and thus predicts the differential and integrated cross sections in the kinematical range appropriate to the LHC. We incorporate the physics of this model into the beam tracking code MERLIN and use it to simulate the resulting loss maps of the beam halo lost in the collimators in the LHC.

  11. Physics of quantum rings

    International Nuclear Information System (INIS)

    Fomin, Vladimir M.

    2014-01-01

    Presents the new class of materials of quantum rings. Provides an elemental basis for low-cost high-performance devices promising for electronics, optoelectronics, spintronics and quantum information processing. Explains the physical properties of quantum rings to cover a gap in scientific literature. Presents the application of most advanced nanoengineering and nanocharacterization techniques. This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is possible on the basis of modern characterization methods of nanostructures, such as Scanning Tunneling Microscopy. A high level of complexity is demonstrated to be needed for a dedicated theoretical model to adequately represent the specific features of quantum rings. The findings presented in this book contribute to develop low-cost high-performance electronic, spintronic, optoelectronic and information processing devices based on quantum rings.

  12. High pressure photoinduced ring opening of benzene

    International Nuclear Information System (INIS)

    Ciabini, Lucia; Santoro, Mario; Bini, Roberto; Schettino, Vincenzo

    2002-01-01

    The chemical transformation of crystalline benzene into an amorphous solid (a-C:H) was induced at high pressure by employing laser light of suitable wavelengths. The reaction was forced to occur at 16 GPa, well below the pressure value (23 GPa) where the reaction normally occurs. Different laser sources were used to tune the pumping wavelength into the red wing of the first excited singlet state S 1 ( 1 B 2u ) absorption edge. Here the benzene ring is distorted, presenting a greater flexibility which makes the molecule unstable at high pressure. The selective pumping of the S 1 level, in addition to structural considerations, was of paramount importance to clarify the mechanism of the reaction

  13. Heavy ion storage rings

    International Nuclear Information System (INIS)

    Schuch, R.

    1987-01-01

    A brief overview of synchrotron storage rings for heavy ions, which are presently under construction in different accelerator laboratories is given. Ions ranging from protons up to uranium ions at MeV/nucleon energies will be injected into these rings using multiturn injection from the accelerators available or being built in these laboratories. After injection, it is planned to cool the phase space distribution of the ions by merging them with cold electron beams or laser beams, or by using stochastic cooling. Some atomic physics experiments planned for these rings are presented. 35 refs

  14. Research support for plasma diagnostics on Elmo Bumpy Torus: investigation of diamagnetic diagnostics for the electron rings

    International Nuclear Information System (INIS)

    Carpenter, K.H.

    1981-02-01

    Diamagnetic diagnostics for the EBT electron rings are fundamental to the experiment. The diamagnetic flux pickup loops on each cavity output signals proportional to ring perpendicular energy. A data analysis technique is described, which in its simplest form is subtracting 1/4 the signal from each neighboring cavity pickup loop from the central one's, which provides a signal proportional to the energy in a single ring. The calibration factor relating absolute perpendicular energy to diamagnetic signal depends weakly on the geometrical model for the ring. Calculations with a bumpy cylinder MHD equilibrium code give calibration factors in reasonable agreement (20%) to the values obtained using a simple, concentric cylindrical current sheet model. The cylindrical current sheet model is used to show that diamagnetic field components measured external to the plasma require high precision or correlation with other diagnostics in order to fix model parameters. A computer simulation shows an assumption of constant ring thickness and energy density with increasing length (and energy) is compatible to diamagnetic field observations on NBT

  15. Development of Stripline Kickers for Low Emittance Rings: Application to the Beam Extraction Kicker for CLIC Damping Rings

    CERN Document Server

    AUTHOR|(SzGeCERN)728476; Toral Fernandez, Fernando

    In the framework of the design study of Future Linear Colliders, the Compact Linear Collider (CLIC) aims for electron-positron collisions with high luminosity at a nominal centre-of-mass energy of 3 TeV. To achieve the luminosity requirements, Pre-Damping Rings (PDRs) and Damping Rings (DRs) are required: they reduce the beam emittance before the beam is accelerated in the main linac. Several injection and extraction systems are needed to inject and extract the beam from the PDRs and DRs. The work of this Thesis consists of the design, fabrication and laboratory tests of the first stripline kicker prototype for beam extraction from the CLIC DRs, although the methodology proposed can be extended to stripline kickers for any low emittance ring. The excellent field homogeneity required, as well as a good transmission of the high voltage pulse through the electrodes, has been achieved by choosing a novel electrode shape. With this new geometry, it has been possible to benefit from all the advantages that the most...

  16. Detecting ultra high energy neutrinos with LOFAR

    International Nuclear Information System (INIS)

    Mevius, M.; Buitink, S.; Falcke, H.; Hörandel, J.; James, C.W.; McFadden, R.; Scholten, O.; Singh, K.; Stappers, B.; Veen, S. ter

    2012-01-01

    The NuMoon project aims to detect signals of Ultra High Energy (UHE) Cosmic Rays with radio telescopes on Earth using the Lunar Cherenkov technique at low frequencies (∼150MHz). The advantage of using low frequencies is the much larger effective detecting volume, with as trade-off the cut-off in sensitivity at lower energies. A first upper limit on the UHE neutrino flux from data of the Westerbork Radio Telescope (WSRT) has been published, while a second experiment, using the new LOFAR telescope, is in preparation. The advantages of LOFAR over WSRT are the larger collecting area, the better pointing accuracy and the use of ring buffers, which allow the implementation of a sophisticated self-trigger algorithm. The expected sensitivity of LOFAR reaches flux limits within the range of some theoretical production models.

  17. Particle identification methods in High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Va' Vra, J.

    2000-01-27

    This paper deals with two major particle identification methods: dE/dx and Cherenkov detection. In the first method, the authors systematically compare existing dE/dx data with various predictions available in the literature, such as the Particle Data group recommendation, and judge the overall consistency. To my knowledge, such comparison was not done yet in a published form for the gaseous detectors used in High-Energy physics. As far as the second method, there are two major Cherenkov light detection techniques: the threshold and the Ring imaging methods. The authors discuss the recent trend in these techniques.

  18. The Ring Current Response to Solar and Interplanetary Storm Drivers

    Science.gov (United States)

    Mouikis, C.; Kistler, L. M.; Bingham, S.; Kronberg, E. A.; Gkioulidou, M.; Huang, C. L.; Farrugia, C. J.

    2014-12-01

    The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CME's), corotating interaction regions (CIR's), high-speed streamers and other structures. The resulting changes in the ring current particle pressure, in turn, change the global magnetic field, controlling the transport of the radiation belts. To quantitatively determine the field changes during a storm throughout the magnetosphere, it is necessary to understand the transport, sources and losses of the particles that contribute to the ring current. Because the measured ring current energy spectra depend not only on local processes, but also on the history of the ions along their entire drift path, measurements of ring current energy spectra at two or more locations can be used to strongly constrain the time dependent magnetic and electric fields. In this study we use data predominantly from the Cluster and the Van Allen Probes, covering more than a full solar cycle (from 2001 to 2014). For the period 2001-2012, the Cluster CODIF and RAPID measurements of the inner magnetosphere are the primary data set used to monitor the storm time ring current variability. After 2012, the Cluster data set complements the data from the Van Allen Probes HOPE and RBSPICE instruments, providing additional measurements from different MLT and L shells. Selected storms from this periods, allow us to study the ring current dynamics and pressure changes, as a function of L shell, magnetic local time, and the type of interplanetary disturbances.

  19. Measurements of the Electron Cloud Density in the PEP-II Low Energy Ring

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, John; De Santis, Stefano; Sonnad, Kiran; Caspers, Fritz; Kroyer, Tom; Krasnykh, Anatoly; Pivi, Mauro

    2008-06-01

    Clouds of low energy electronsin the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energyelectron clouds over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave that is independently excited and transmitted over a section of the accelerator. We infer the absolute phase shift with relatively high accuracy from the phase modulation of the transmission due to the modulation of the electron cloud density from a gap in the positively charged beam. We have used this technique for the first time to measure the average electron cloud density over a 50 m straight section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center. We have also measured the variation of the density by using low field solenoid magnets to control the electrons.

  20. Parameter scan for the CLIC Damping rings under the infleunce of intrabeam scattering

    OpenAIRE

    Antoniou, F; Martini, M; Papaphilippou, Y; Vivoli, A

    2010-01-01

    Due to the high bunch density, the output emittances of the CLIC Damping Rings (DR) are strongly dominated by the effect of Intrabeam Scattering (IBS). In an attempt to optimize the ring design, the bench-marking of the multiparticle tracking code SIRE with the classical IBS formalisms and approximations is first considered. The scaling of the steady state emittances and IBS growth rates is also studied, with respect to several ring parameters including energy, bunch charge and wiggler charac...

  1. Parameter scan for the CLIC Damping rings under the infleunce of intrabeam scattering

    CERN Document Server

    Antoniou, F; Papaphilippou, Y; Vivoli, A

    2010-01-01

    Due to the high bunch density, the output emittances of the CLIC Damping Rings (DR) are strongly dominated by the effect of Intrabeam Scattering (IBS). In an attempt to optimize the ring design, the bench-marking of the multiparticle tracking code SIRE with the classical IBS formalisms and approximations is first considered. The scaling of the steady state emittances and IBS growth rates is also studied, with respect to several ring parameters including energy, bunch charge and wiggler characteristics.

  2. Bond-equilibrium theory of liquid Se-Te alloys. II. Effect of singly attached ring molecules

    Science.gov (United States)

    Cutler, Melvin; Bez, Wolfgang G.

    1981-06-01

    A statistical-mechanical theory for bond equilibrium of chain polymers containing threefold (3F) and onefold (1F) bond defects is extended to include the effects of free ring molecules and ring molecules attached to chains by a single 3F atom. Positively charged singly attached rings are shown to play a key role in bond equilibrium in liquid Sex Te1-x by permitting the formation of ion pairs in which both constituents are effectively chain terminators, thus decreasing the average polymer size. The theory is applied to explain the behavior of the paramagnetic susceptibility, χp, and electronic transport as affected by the Fermi energy EF. It is found that the increase in χp with the concentration of Te is primarily the result of the smaller energy for breaking Te bonds. In addition, attached rings play an important role in determining the effect of temperature on χp. At x<~0.5, the concentrations of both free and attached rings becomes small at high T because of the high concentration of bond defects.

  3. The impact of exospheric neutral dynamics on ring current decay

    Science.gov (United States)

    Ilie, R.; Liemohn, M. W.; Skoug, R. M.; Funsten, H. O.; Gruntman, M.; Bailey, J. J.; Toth, G.

    2015-12-01

    The geocorona plays an important role in the energy budget of the Earth's inner magnetosphere since charge exchange of energetic ions with exospheric neutrals makes the exosphere act as an energy sink for ring current particles. Long-term ring current decay following a magnetic storm is mainly due to these electron transfer reactions, leading to the formation energetic neutral atoms (ENAs) that leave the ring current system on ballistic trajectories. The number of ENAs emitted from a given region of space depends on several factors, such as the energy and species of the energetic ion population in that region and the density of the neutral gas with which the ions undergo charge exchange. However, the density and structure of the exosphere are strongly dependent on changes in atmospheric temperature and density as well as charge exchange with the ions of plasmaspheric origin, which depletes the geocorona (by having a neutral removed from the system). Moreover, the radiation pressure exerted by solar far-ultraviolet photons pushes the geocoronal hydrogen away from the Earth in an anti-sunward direction to form a tail of neutral hydrogen. TWINS ENA images provide a direct measurement of these ENA losses and therefore insight into the dynamics of the ring current decay through interactions with the geocorona. We assess the influence of geocoronal neutrals on ring current formation and decay by analysis of the predicted ENA emissions using 6 different geocoronal models and simulations from the HEIDI ring current model during storm time. Comparison with TWINS ENA images shows that the location of the peak ENA enhancements is highly dependent on the distribution of geocoronal hydrogen density. We show that the neutral dynamics has a strong influence on the time evolution of the ring current populations as well as on the formation of energetic neutral atoms.

  4. CRYOGENIC AND VACUUM TECHNOLOGICAL ASPECTS OF THE LOW-ENERGY ELECTROSTATIC CRYOGENIC STORAGE RING

    International Nuclear Information System (INIS)

    Orlov, D. A.; Lange, M.; Froese, M.; Hahn, R. von; Grieser, M.; Mallinger, V.; Sieber, T.; Weber, T.; Wolf, A.; Rappaport, M.

    2008-01-01

    The cryogenic and vacuum concepts for the electrostatic Cryogenic ion Storage Ring (CSR), under construction at the Max-Planck-Institut fuer Kernphysik in Heidelberg, is presented. The ring will operate in a broad temperature range from 2 to 300 K and is required to be bakeable up to 600 K. Extremely high vacuum and low temperatures are necessary to achieve long lifetimes of the molecular ions stored in the ring so that the ions will have enough time to cool by radiation to their vibrational and rotational ground states. To test cryogenic and vacuum technological aspects of the CSR, a prototype is being built and will be connected to the commercial cryogenic refrigerator recently installed, including a specialized 2-K connection system. The first results and the status of current work with the prototype are also presented

  5. Characteristics of hot electron ring in a simple magnetic mirror field

    International Nuclear Information System (INIS)

    Hosokawa, M.; Ikegami, H.

    1980-12-01

    Characteristics of hot electron ring are studied in a simple magnetic mirror machine (mirror ratio 2 : 1) with a diameter of 30 cm at the midplane and with the distance of 80 cm between the mirrors. Maximum microwave input power is 5 kW at 6.4 GHz with the corresponding power density of approximately 0.3 W/cm 3 . With a background cold plasma of 4 x 10 11 cm -3 , hot electron rings are most effectively generated in two cases when the magnetic field on the axis of the midplane is set near the fundamental or the second harmonic electron cyclotron resonance to the applied microwave frequency. Density profile of the hot electrons is observed to take a so-called ring shape with a radius controllable by the magnetic field intensity and with an axial length of approximately 10 cm. The radial cut view of the ring, however, indicates an M shape density profile, and the density of the hot electrons on the axis is about one half of the density at the ring. Approximately 30 msec is needed before generating the hot electron ring at the density of 10 10 cm -3 with an average kinetic energy of 100 keV. The ultimate energy distribution function is observed to have a stepwise cut in the high energy tail and no energetic components above 1 MeV are detected. The hot electron ring is susceptible to a few instabilities which can be artificially triggered. One of the instabilities is observed to associate with a loss of lower energetic electrons and microwave bursts. At the instability, the ring shape is observed to transform into a filled cylinder in a few microseconds and disappear. (author)

  6. Optics design of Intrabeam Scattering dominated damping rings

    CERN Document Server

    Antoniou, Fanouria; Papaphilippou, Ioannis

    A e+/e- linear collider, the Compact Linear Collider (CLIC) is under design at CERN, aiming to explore the terascale particle physics regime. The collider has been optimized at 3 TeV center of mass energy and targets a luminosity of 1034 cm-2 s-1. In order to achieve this high luminosity, high intensity bunches with ultra low emittances, in all three planes, are required. The generation of ultra low emittance is achieved in the Damping Rings (DR) complex of the collider. The large input beam emittances, especially the ones coming from the positron source, and the requirement of ultra low emittance production in a fast repetition time of 20 ms, imply that the beam damping is done in two stages. Thus, a main-damping ring (DR) and a predamping ring (PDR) are needed, for each particle species. The high bunch brightness gives rise to several collective effects, with Intra-beam scattering (IBS) being the main limitation to the ultra-low emittance. This thesis elaborates the lattice design and non-linear optimizatio...

  7. Rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation

    Energy Technology Data Exchange (ETDEWEB)

    Teshima, Hidekazu [Nippon Steel Corp., Kawasaki, Kanagawa (Japan). Advanced Materials and Technology Research Labs.; Tawara, Taichi; Shimada, Ryuichi

    1997-08-01

    This paper describes the experimental results for the rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub because it is a non-contact and automatically stable levitation without any control systems. The rotational loss has been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The rotational loss decreased as the levitation gap height increased. In low-speed rotational regions, the rotational loss was in proportion to the rotation speed and depended more on the levitation gap. In high-speed rotational regions, the rotational loss was in proportion to the third power of the rotation speed and depended less on the levitation gap. The cubic rotational loss in He was reduced to one-fifth of that in air. The magnetic field pinned in bulk superconductors induces a loss in the materials composing the ring-shaped flywheel. The rotational loss of a ring-shaped flywheel supported by superconducting levitation can be reduced by improving the uniformity of the magnetic fields along the ring, enlargement of the bulk superconductor(s), and densely arranging the bulk superconductors. (author)

  8. Polarized targets in high energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Cates, G.D. Jr. [Princeton Univ., NJ (United States)

    1994-12-01

    Various approaches are discussed for producing polarized nuclear targets for high energy physics experiments. As a unifying theme, examples are drawn from experiments to measure spin dependent structure functions of nucleons in deep inelastic scattering. This single physics goal has, over roughly two decades, been a driving force in advances in target technology. Actual or planned approaches have included solid targets polarized by dynamic nuclear polarization (DNP), several types of internal targets for use in storage rings, and gaseous {sup 3}He targets polarized by spin-exchange optical pumping. This last approach is the type of target adopted for SLAC E-142, an experiment to measure the spin structure function of the neutron, and is described in detail.

  9. Polarized targets in high energy physics

    International Nuclear Information System (INIS)

    Cates, G.D. Jr.

    1994-01-01

    Various approaches are discussed for producing polarized nuclear targets for high energy physics experiments. As a unifying theme, examples are drawn from experiments to measure spin dependent structure functions of nucleons in deep inelastic scattering. This single physics goal has, over roughly two decades, been a driving force in advances in target technology. Actual or planned approaches have included solid targets polarized by dynamic nuclear polarization (DNP), several types of internal targets for use in storage rings, and gaseous 3 He targets polarized by spin-exchange optical pumping. This last approach is the type of target adopted for SLAC E-142, an experiment to measure the spin structure function of the neutron, and is described in detail

  10. A Stereoselective [3+1] Ring Expansion for the Synthesis of Highly Substituted Methylene Azetidines.

    Science.gov (United States)

    Schmid, Steven C; Guzei, Ilia A; Schomaker, Jennifer M

    2017-09-25

    The reaction of rhodium-bound carbenes with strained bicyclic methylene aziridines results in a formal [3+1] ring expansion to yield highly substituted methylene azetidines with excellent regio- and stereoselectivity. The reaction appears to proceed through an ylide-type mechanism, where the unique strain and structure of the methylene aziridine promotes a ring-opening/ring-closing cascade that efficiently transfers chirality from substrate to product. The resultant products can be elaborated into new azetidine scaffolds containing vicinal tertiary-quaternary and even quaternary-quaternary stereocenters. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Mechanical improvement of metal reinforcement rings for a finite ring-shaped superconducting bulk

    Science.gov (United States)

    Huang, Chen-Guang; Zhou, You-He

    2018-03-01

    As a key technique, reinforcement of type-II superconducting bulks with metal rings can efficiently improve their mechanical properties to enhance the maximum trapped field. In this paper, we study the magnetostrictive and fracture behaviors of a finite superconducting ring bulk reinforced by three typical reinforcing structures composed of metal rings during the magnetizing process by means of the minimization of magnetic energy and the finite element method. After a field-dependent critical current density is adopted, the magnetostriction, pinning-induced stress, and crack tip stress intensity factor are calculated considering the demagnetization effects. The results show that the mechanical properties of the ring bulk are strongly dependent on the reinforcing structure and the material and geometrical parameters of the metal rings. Introducing the metal ring can significantly reduce the hoop stress, and the reduction effect by internal reinforcement is much improved relative to external reinforcement. By comparison, bilateral reinforcement seems to be the best candidate structure. Only when the metal rings have particular Young's modulus and radial thickness will they contribute to improve the mechanical properties the most. In addition, if an edge crack is pre-existing in the ring bulk, the presence of metal rings can effectively avoid crack propagation since it reduces the crack tip stress intensity factor by nearly one order of magnitude.

  12. Influence of ring growth rate on damage development in hot ring rolling

    NARCIS (Netherlands)

    Wang, C.; Geijselaers, H. J.M.; Omerspahic, E.; Recina, V.; van den Boogaard, A. H.

    2015-01-01

    As an incremental forming process of bulk metal, ring rolling provides a cost effective process route to manufacture seamless rings. In the production of hot rolled rings, defects such as porosity can sometimes be found in high alloyed steel, manufactured from ingots having macro-segregation. For

  13. Optimization design of high power ultrasonic circular ring radiator in coupled vibration.

    Science.gov (United States)

    Xu, Long; Lin, Shuyu; Hu, Wenxu

    2011-10-01

    This paper presents a new high power ultrasonic (HPU) radiator, which consists of a transducer, an ultrasonic horn, and a metal circular ring. Both the transducer and horn in longitudinal vibrations are used to drive a metal circular ring in a radial-axial coupled vibration. This coupled vibration cannot only generate ultrasound in both the radial and axial directions, but also focus the ultrasound inside the circular ring. Except for the radial-axial coupled vibration mode, the third longitudinal harmonic vibration mode with relative large vibration amplitude is also detected, which can be used as another operation mode. Overall, the HPU with these two vibration modes should have good potential to be applied in liquid processing, such as sonochemistry, ultrasonic cleaning, and Chinese herbal medicine extraction. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Status of the SLC damping rings

    International Nuclear Information System (INIS)

    Hutton, A.M.; Davies-White, W.A.; Delahaye, J.P.

    1985-06-01

    Electron beams of full design energy 1.21 GeV and nearly full design intensity 4 x 10 10 particles/pulse (design 5 x 10 10 ) have been extracted from the Stanford Linac and successfully stored in the electron damping ring. Beams of less intensity have been extracted from the ring and reinjected into the Linac. The present intensity limits are not thought to be fundamental. The operating experience with the electron ring and the status of the construction of the positron ring will be discussed. 11 refs., 1 fig., 2 tabs

  15. Survey of Digital Feedback Systems in High Current Storage Rings

    International Nuclear Information System (INIS)

    Teytelman, Dmitry

    2003-01-01

    In the last decade demand for brightness in synchrotron light sources and luminosity in circular colliders led to construction of multiple high current storage rings. Many of these new machines require feedback systems to achieve design stored beam currents. In the same time frame the rapid advances in the technology of digital signal processing allowed the implementation of these complex feedback systems. In this paper I concentrate on three applications of feedback to storage rings: orbit control in light sources, coupled-bunch instability control, and low-level RF control. Each of these applications is challenging in areas of processing bandwidth, algorithm complexity, and control of time-varying beam and system dynamics. I will review existing implementations as well as comment on promising future directions

  16. Acceleration of compact torus plasma rings in a coaxial rail-gun

    International Nuclear Information System (INIS)

    Hartman, C.W.; Hammer, J.H.; Eddleman, J.

    1986-01-01

    They discuss here theoretical studies of magnetic acceleration of Compact Torus plasma rings in a coaxial, rail-gun accelerator. The rings are formed using a magnetized coaxial plasma gun and are accelerated by injection of B/sub Theta/ flux from an accelerator bank. After acceleration, the rings enter a focusing cone where the ring is decelerated and reduced in radius. As the ring radius decreases, the ring magnetic energy increases until it equals the entering kinetic energy and the ring stagnates. Scaling laws and numerical calculations of acceleration using a O-D numerical code are presented. 2-D, MHD simulations are shown which demonstrate ring formation, acceleration, and focusing. Finally, 3-D calculations are discussed which determine the ideal MHD stability of the accelerated ring

  17. Acceleration of compact torus plasma rings in a coaxial rail-gun

    International Nuclear Information System (INIS)

    Hartman, C.W.; Hammer, J.H.; Eddleman, J.

    1985-01-01

    We discuss here theoretical studies of magnetic acceleration of Compact Torus plasma rings in a coaxial, rail-gun accelerator. The rings are formed using a magnetized coaxial plasma gun and are accelerated by injection of B/sub theta/ flux from an accelerator bank. After acceleration, the rings enter a focusing cone where the ring is decelerated and reduced in radius. As the ring radius decreases, the ring magnetic energy increases until it equals the entering kinetic energy and the ring stagnates. Scaling laws and numerical calculations of acceleration using a O-D numerical code are presented. 2-D, MHD simulations are shown which demonstrate ring formation, acceleration, and focusing. Finally, 3-D calculations are discussed which determine the ideal MHD stability of the accelerated ring

  18. Serial imaging and structure-function correlates of high-density rings of fundus autofluorescence in retinitis pigmentosa.

    Science.gov (United States)

    Robson, Anthony G; Tufail, Adnan; Fitzke, Fred; Bird, Alan C; Moore, Anthony T; Holder, Graham E; Webster, Andrew R

    2011-09-01

    To document the evolution and functional and structural significance of parafoveal rings of high-density fundus autofluorescence (AF) in patients with retinitis pigmentosa and preserved visual acuity. Fifty-two patients with nonsyndromic retinitis pigmentosa or Usher syndrome, who had a parafoveal ring of high-density AF and a visual acuity of 20/30 or better, were ascertained. All had international standard full-field electroretinography and pattern electroretinography. Autofluorescence imaging was repeated in 30 patients after periods of up to 9.3 years. Of the 52 patients, 35 underwent optical coherence tomography. Progressive constriction of the ring was detected in 17 patients. Ring radius reduced by up to 40% at a mean rate of between 0.8% and 15.8% per year. In 1 patient, a small ring was replaced by irregular AF; visual acuity deteriorated over the same period. There was a high correspondence between the lateral extent of the preserved optical coherence tomography inner segment/outer segment band and the diameter of the ring along the same optical coherence tomographic scan plane (slope, 0.9; r = 0.97; P retina and preserved photopic function. Serial fundus AF may provide prognostic indicators for preservation of central acuity and potentially assist in the identification and evaluation of patients suitable for treatment aimed at preservation of remaining function.

  19. Energy cascade with small-scale thermalization, counterflow metastability, and anomalous velocity of vortex rings in Fourier-truncated Gross-Pitaevskii equation

    International Nuclear Information System (INIS)

    Krstulovic, Giorgio; Brachet, Marc

    2011-01-01

    The statistical equilibria of the (conservative) dynamics of the Gross-Pitaevskii equation (GPE) with a finite range of spatial Fourier modes are characterized using a new algorithm, based on a stochastically forced Ginzburg-Landau equation (SGLE), that directly generates grand-canonical distributions. The SGLE-generated distributions are validated against finite-temperature GPE-thermalized states and exact (low-temperature) results obtained by steepest descent on the (grand-canonical) partition function. A standard finite-temperature second-order λ transition is exhibited. A mechanism of GPE thermalization through a direct cascade of energy is found using initial conditions with mass and energy distributed at large scales. A long transient with partial thermalization at small scales is observed before the system reaches equilibrium. Vortices are shown to disappear as a prelude to final thermalization and their annihilation is related to the contraction of vortex rings due to mutual friction. Increasing the amount of dispersion at the truncation wave number is shown to slow thermalization and vortex annihilation. A bottleneck that produces spontaneous effective self-truncation with partial thermalization is characterized in the limit of large dispersive effects. Metastable counterflow states, with nonzero values of momentum, are generated using the SGLE algorithm. Spontaneous nucleation of the vortex ring is observed and the corresponding Arrhenius law is characterized. Dynamical counterflow effects on vortex evolution are investigated using two exact solutions of the GPE: traveling vortex rings and a motionless crystal-like lattice of vortex lines. Longitudinal effects are produced and measured on the crystal lattice. A dilatation of vortex rings is obtained for counterflows larger than their translational velocity. The vortex ring translational velocity has a dependence on temperature that is an order of magnitude above that of the crystal lattice, an effect

  20. Extra Low Energy Antiproton ring ELENA : from the conception to the implementation phase

    CERN Document Server

    Bartmann, W; Breuker, H; Butin, F; Carli, C; Eriksson, T; Maury, S; Pasinelli, S; Tranquille, G; Oelert, W

    2014-01-01

    The Extra Low Energy Antiproton ring (ELENA) is a CERN project aiming at constructing a small 30 m circumference synchrotron to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. The ELENA design is now well advanced and the project is moving to the implementation phase. Component design and construction are taking place at present for installation foreseen during the second half of 2015 and beginning of 2016 followed by ring commissioning until the end of 2016. New electrostatic transfer lines to the experiments will be installed and commissioned during the first half of 2017 followed by the first physics operation with ELENA. Basic limitations like Intra Beam Scattering limiting the emittances obtained under electron ...

  1. Half-integer resonance crossing in high-intensity rings

    Directory of Open Access Journals (Sweden)

    A. V. Fedotov

    2002-02-01

    Full Text Available A detailed study of the influence of space charge on the crossing of second-order resonances is presented and associated with the space-charge limit of high-intensity rings. Two-dimensional simulation studies are compared with envelope models, which agree in the finding of an increased intensity limit due to the coherent frequency shift. This result is also found for realistic bunched beams with multiturn injection painting. Characteristic features such as the influence of tune splitting, structure resonances, and the role of envelope instabilities are discussed in detail. The theoretical limits are found to be in good agreement with the performance of high-intensity proton machines.

  2. Lit and unlit side temperatures of the Main Rings of Saturn.

    Science.gov (United States)

    Flandes, A.; Garcia, A.; Deau, E.; Spilker, L. J.

    2017-12-01

    The differences in the temperatures of both the lit and unlit sides of the main rings of Saturn can reveal important information about their structure. In general, the temperature of the main rings strongly depends upon the distribution and the general structure of the ensembles of particles that compose them, mainly due to shadowing effects that modulate how much energy reaches the individual particles -granted that the direct solar energy is the main driver of the rings' temperature-. In order to reproduce the temperatures of both sides of the rings, we use a semi-analytical energy balance model (considering solar direct and Saturn reflected energy, Saturn thermal energy and particles' thermal energies), where the shadowed fractional areas of the rings are removed through a shadowing function. We obtain this function (dependent on the solar elevation angle) for 13 different regions (for the A, CD, B and C rings) along the radial direction that are simulated using arrays of lambertian spherical particles based on the average properties of the structure of these regions derived from the Cassini UVIS observations. The obtained synthetic temperatures are compared to the Cassini CIRS measured temperatures (from -22º to equinox) with good agreement.

  3. High-speed schlieren videography of vortex-ring impact on a wall

    Science.gov (United States)

    Kissner, Benjamin; Hargather, Michael; Settles, Gary

    2011-11-01

    Ring vortices of approximately 20 cm diameter are generated through the use of an Airzooka toy. To make the vortex visible, it is seeded with difluoroethane gas, producing a refractive-index difference with the air. A 1-meter-diameter, single-mirror, double-pass schlieren system is used to visualize the ring-vortex motion, and also to provide the wall with which the vortex collides. High-speed imaging is provided by a Photron SA-1 digital video camera. The Airzooka is fired toward the mirror almost along the optical axis of the schlieren system, so that the view of the vortex-mirror collision is normal to the path of vortex motion. Vortex-wall interactions similar to those first observed by Walker et al. (JFM 181, 1987) are recorded at high speed. The presentation will consist of a screening and discussion of these video results.

  4. Ring coil optimization with respect to stress, temperature, and system energy over a range of physics requirements

    International Nuclear Information System (INIS)

    Pillsbury, R.D. Jr; Thome, R.J.

    1987-01-01

    The poloidal field coil system for a tokamak can be divided into the central solenoid and the ring coils. A ring coil is defined as one that has a small cross-section compared to its diameter. The size of the central solenoid is usually fixed very early in the design process since its size is directly related to the tokamak size. The sizes of the other (ring) coils are not as critical to determining the basic machine size. It is necessary to know their locations and currents in order to verify the shaping and position control of the plasma. Attention is usually focused only on the baseline plasma of the design point. However, the PF set must also be able to shape and maintain other plasmas. This paper describes a program which evaluates PF coil current scenarios over a range of physics requirements and determines the sizes of the coils necessary to satisfy constraints on the temperature rise and stress levels for the worst case scenario. In addition, the system energy requirements can be assessed and trade-offs between system energy and coil sizes (cost) can be made. Examples are given based on studies performed of CIT (Compact Ignition Tokamak)

  5. High performance ring oscillators from 10-nm wide silicon nanowire field-effect transistors

    KAUST Repository

    Huang, Ruo-Gu; Tham, Douglas; Wang, Dunwei; Heath, James R.

    2011-01-01

    We explore 10-nm wide Si nanowire (SiNW) field-effect transistors (FETs) for logic applications, via the fabrication and testing of SiNW-based ring oscillators. We report on SiNW surface treatments and dielectric annealing, for producing SiNW FETs that exhibit high performance in terms of large on/off-state current ratio (~108), low drain-induced barrier lowering (~30 mV) and low subthreshold swing (~80 mV/decade). The performance of inverter and ring-oscillator circuits fabricated from these nanowire FETs are also explored. The inverter demonstrates the highest voltage gain (~148) reported for a SiNW-based NOT gate, and the ring oscillator exhibits near rail-to-rail oscillation centered at 13.4 MHz. The static and dynamic characteristics of these NW devices indicate that these SiNW-based FET circuits are excellent candidates for various high-performance nanoelectronic applications. © 2011 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

  6. High performance ring oscillators from 10-nm wide silicon nanowire field-effect transistors

    KAUST Repository

    Huang, Ruo-Gu

    2011-06-24

    We explore 10-nm wide Si nanowire (SiNW) field-effect transistors (FETs) for logic applications, via the fabrication and testing of SiNW-based ring oscillators. We report on SiNW surface treatments and dielectric annealing, for producing SiNW FETs that exhibit high performance in terms of large on/off-state current ratio (~108), low drain-induced barrier lowering (~30 mV) and low subthreshold swing (~80 mV/decade). The performance of inverter and ring-oscillator circuits fabricated from these nanowire FETs are also explored. The inverter demonstrates the highest voltage gain (~148) reported for a SiNW-based NOT gate, and the ring oscillator exhibits near rail-to-rail oscillation centered at 13.4 MHz. The static and dynamic characteristics of these NW devices indicate that these SiNW-based FET circuits are excellent candidates for various high-performance nanoelectronic applications. © 2011 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

  7. First design for the optics of the decay ring for the beta-beams

    International Nuclear Information System (INIS)

    Chance, A.; Payet, J.

    2006-03-01

    The aim of the beta-beams is to produce pure electronic neutrino and anti-neutrino highly energetic beams, coming from beta radioactive disintegration decay of the 18 Ne 10+ and 6 He 2+ , directed to experiment situated in the Frejus tunnel. The high ion intensities are stored in a ring, until the ions decay. The losses due to the decay of the radioactive ions are compensated with regular injections. These should be done in presence of the circulating beam. The new ions are injected at a different energy from the stored beam energy, the design of the ring must enable this type of injection and accept the injected and stored beams. In this note, we will focus on the study of the design of such a ring at the first and second orders. We have reached the constraint on the dispersion in the injection section: a horizontal dispersion superior to 10 m with β x = 20 m. We have put sextupoles in the arcs to correct the chromaticity. In the same time, we have compensated the third order resonances to have a large enough dynamic aperture. So the decay ring accepts injected and stored beams. In a top-down approach, the high stored intensities impose to take into account the space charge effects. However, due to the merging, the beam blows up after each injection in the longitudinal space charge, which imposes to include a momentum collimation section in the decay ring

  8. A feasibility study of a neutrino source based on a muon storage ring

    CERN Document Server

    Finley, D

    2001-01-01

    We present the results of a study commissioned by the Fermilab Director on the feasibility of an intense neutrino source, based on a muon storage ring. Muon colliders have been discussed as an alternate route to very high-energy lepton colliders. As a by-product, such a collider would produce very intense neutrino beams because of the decaying muons circulating in the storage ring. In a dedicated storage ring, these neutrino beams could be produced in long straight sections which would point towards long, medium or short baseline detectors, opening up a whole new class of neutrino physics experiments because of the enormous neutrino flux that, in principle, could be achieved in such a facility as compared to more standard fixed target sources. Intense pion sources in combination with powerful emittance cooling strategies for the comparatively large muon emittance are necessary to make this type of neutrino source as well as a muon collider, feasible for a possible future high energy physics facility. The Neut...

  9. High energy physics at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Samios, N.P.

    1982-01-01

    The high energy plans at BNL are centered around the AGS and ISABELLE, or a variant thereof. At present the AGS is maintaining a strong and varied program. This last year a total of 4 x 10 19 protons were delivered on target in a period of approximately 20 weeks. Physics interest is very strong, half of the submitted proposals are rejected (thereby maintaining high quality experiments) and the program is full over the next two years. The future colliding beam facility will utilize the AGS as an injector and will be a dedicated facility. It will have six intersection regions, run > 10 7 sec/year, and explore a new domain of energy and luminosity. Common to all the considered alternatives is a large aperture proton ring. These possible choices involve pp, ep, and heavy ion variants. The long term philosophy is to run the AGS as much as possible, continuously to upgrade it in performance and reliability, and then to phase it down as the new collider begins operation

  10. Ion transport and loss in the earth's quiet ring current. I - Data and standard model

    Science.gov (United States)

    Sheldon, R. B.; Hamilton, D. C.

    1993-01-01

    A study of the transport and loss of ions in the earth's quiet time ring current, in which the standard radial diffusion model developed for the high-energy radiation belt particles is compared with the measurements of the lower-energy ring current ions, is presented. The data set provides ionic composition information in an energy range that includes the bulk of the ring current energy density, 1-300 keV/e. Protons are found to dominate the quiet time energy density at all altitudes, peaking near L of about 4 at 60 keV/cu cm, with much smaller contributions from O(+) (1-10 percent), He(+) (1-5 percent), and He(2+) (less than 1 percent). A minimization procedure is used to fit the amplitudes of the standard electric radial diffusion coefficient, yielding 5.8 x 10 exp -11 R(E-squared)/s. Fluctuation ionospheric electric fields are suggested as the source of the additional diffusion detected.

  11. High Resolution BPM Upgrade for the ATF Damping Ring at KEK

    International Nuclear Information System (INIS)

    Eddy, N.; Briegel, C.; Fellenz, B.; Gianfelice-Wendt, E.; Prieto, P.; Rechenmacher, R.; Semenov, A.; Voy, D.; Wendt, M.; Zhang, D.; Terunuma, N.

    2011-01-01

    A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility (ATF) damping ring has been accomplished, carried out by a KEK/FNAL/SLAC collaboration under the umbrella of the global ILC R and D effort. The upgrade consists of a high resolution, high reproducibility read-out system, based on analog and digital down-conversion techniques, digital signal processing, and also implements a new automatic gain error correction schema. The technical concept and realization as well as results of beam studies are presented. The next generation of linear colliders require ultra-low vertical emittance of <2 pm-rad. The damping ring at the KEK Accelerator Test Facility (ATF) is designed to demonstrate this mission critical goal. A high resolution beam position monitor (BPM) system for the damping ring is one of the key tools for realizing this goal. The BPM system needs to provide two distnict measurements. First, a very high resolution (∼100-200nm) closed-orbit measurement which is averaged over many turns and realized with narrowband filter techniques - 'narrowband mode'. This is needed to monitor and steer the beam along an optimum orbit and to facilitate beam-based alignment to minimize non-linear field effects. Second, is the ability to make turn by turn (TBT) measurements to support optics studies and corrections necessary to achieve the design performance. As the TBT measurement necessitates a wider bandwidth, it is often referred to as 'wideband mode'. The BPM upgrade was initiated as a KEK/SLAC/FNAL collaboration in the frame of the Global Design Initiative of the International Linear Collider. The project was realized and completed using Japan-US funds with Fermilab as the core partner.

  12. Results from the RACE [Ring ACceleration Experiment] Compact Torus Acceleration Experiment

    International Nuclear Information System (INIS)

    Hammer, J.H.; Hartman, C.W.; Eddleman, J.L.; Kusse, B.

    1987-06-01

    RACE (Ring ACceleration Experiment) is a proof-of-principle experiment aimed at demonstrating acceleration of magnetically confined compact torus plasma rings to directed kinetic energies well in excess of their magnetic and thermal energies. In the course of the first year of operation the following have been observed: successful formation of rings in the RACE geometry; acceleration of rings with large forces, F/sub accelerate/ ∼F/sub equilibrium/ without apparent degradation of the ring structure; peak velocities of ≅2.5 x 10 8 cm/sec; acceleration efficiency of >30% at speeds of 1.5 x 10 8 cm/sec inferred from trajectory and capacitor bank data; kinetic to magnetic energy ratios ∼10 were observed. Experiments in the near future will be aimed at confirmation of the mass/energy measurements by calorimetry and direct density measurements

  13. Electron transport in a double quantum ring: Evidence of an AND gate

    International Nuclear Information System (INIS)

    Maiti, Santanu K.

    2009-01-01

    We explore AND gate response in a double quantum ring where each ring is threaded by a magnetic flux φ. The double quantum ring is attached symmetrically to two semi-infinite one-dimensional metallic electrodes and two gate voltages, namely, V a and V b , are applied, respectively, in the lower arms of the two rings which are treated as two inputs of the AND gate. The system is described in the tight-binding framework and the calculations are done using the Green's function formalism. Here we numerically compute the conductance-energy and current-voltage characteristics as functions of the ring-to-electrode coupling strengths, magnetic flux and gate voltages. Our study suggests that, for a typical value of the magnetic flux φ=φ 0 /2 (φ 0 =ch/e, the elementary flux-quantum) a high output current (1) (in the logical sense) appears only if both the two inputs to the gate are high (1), while if neither or only one input to the gate is high (1), a low output current (0) results. It clearly demonstrates the AND gate behavior and this aspect may be utilized in designing an electronic logic gate.

  14. Measurements of the electron cloud in the APS storage ring

    International Nuclear Information System (INIS)

    Harkey, K. C.

    1999-01-01

    Synchrotron radiation interacting with the vacuum chamber walls in a storage ring produce photoelectrons that can be accelerated by the beam, acquiring sufficient energy to produce secondary electrons in collisions with the walls. If the secondary-electron yield (SEY) coefficient of the wall material is greater than one, as is the case with the aluminum chambers in the Advanced Photon Source (APS) storage ring, a runaway condition can develop. As the electron cloud builds up along a train of stored positron or electron bunches, the possibility exists that a transverse perturbation of the head bunch will be communicated to trailing bunches due to interaction with the cloud. In order to characterize the electron cloud, a special vacuum chamber was built and inserted into the ring. The chamber contains 10 rudimentary electron-energy analyzers, as well as three targets coated with different materials. Measurements show that the intensity and electron energy distribution are highly dependent on the temporal spacing between adjacent bunches and the amount of current contained in each bunch. Furthermore, measurements using the different targets are consistent with what would be expected based on the SEY of the coatings. Data for both positron and electron beams are presented

  15. Comparing Sources of Storm-Time Ring Current O+

    Science.gov (United States)

    Kistler, L. M.

    2015-12-01

    The first observations of the storm-time ring current composition using AMPTE/CCE data showed that the O+ contribution to the ring current increases significantly during storms. The ring current is predominantly formed from inward transport of the near-earth plasma sheet. Thus the increase of O+ in the ring current implies that the ionospheric contribution to the plasma sheet has increased. The ionospheric plasma that reaches the plasma sheet can come from both the cusp and the nightside aurora. The cusp outflow moves through the lobe and enters the plasma sheet through reconnection at the near-earth neutral line. The nightside auroral outflow has direct access to nightside plasma sheet. Using data from Cluster and the Van Allen Probes spacecraft, we compare the development of storms in cases where there is a clear input of nightside auroral outflow, and in cases where there is a significant cusp input. We find that the cusp input, which enters the tail at ~15-20 Re becomes isotropized when it crosses the neutral sheet, and becomes part of the hot (>1 keV) plasma sheet population as it convects inward. The auroral outflow, which enters the plasma sheet closer to the earth, where the radius of curvature of the field line is larger, does not isotropize or become significantly energized, but remains a predominantly field aligned low energy population in the inner magnetosphere. It is the hot plasma sheet population that gets accelerated to high enough energies in the inner magnetosphere to contribute strongly to the ring current pressure. Thus it appears that O+ that enters the plasma sheet further down the tail has a greater impact on the storm-time ring current than ions that enter closer to the earth.

  16. On the Optimum Dispersion of a Storage Ring for Electron Cooling with High Space Charge

    CERN Document Server

    Bosser, Jacques; Chanel, M; Marié, L; Möhl, D; Tranquille, G

    2000-01-01

    With the intense electron beams used for cooling, matching of the ion and electron velocity over the largest possible fraction of the beam profile becomes important. In this situation, a finite dispersion from the ring in the cooling section can lead to an appreciable gain in the transverse cooling speed. Based on a simple model of the cooling force, an expression for the "optimum" dispersion as a function of the electron beam intensity, the momentum spread and other properties of the ion beam will be derived. This simple theory will be compared to measurements made on the Low Energy Ion Ring (LEIR) at CERN during 1997.

  17. Quantized Self-Assembly of Discotic Rings in a Liquid Crystal Confined in Nanopores

    Science.gov (United States)

    Sentker, Kathrin; Zantop, Arne W.; Lippmann, Milena; Hofmann, Tommy; Seeck, Oliver H.; Kityk, Andriy V.; Yildirim, Arda; Schönhals, Andreas; Mazza, Marco G.; Huber, Patrick

    2018-02-01

    Disklike molecules with aromatic cores spontaneously stack up in linear columns with high, one-dimensional charge carrier mobilities along the columnar axes, making them prominent model systems for functional, self-organized matter. We show by high-resolution optical birefringence and synchrotron-based x-ray diffraction that confining a thermotropic discotic liquid crystal in cylindrical nanopores induces a quantized formation of annular layers consisting of concentric circular bent columns, unknown in the bulk state. Starting from the walls this ring self-assembly propagates layer by layer towards the pore center in the supercooled domain of the bulk isotropic-columnar transition and thus allows one to switch on and off reversibly single, nanosized rings through small temperature variations. By establishing a Gibbs free energy phase diagram we trace the phase transition quantization to the discreteness of the layers' excess bend deformation energies in comparison to the thermal energy, even for this near room-temperature system. Monte Carlo simulations yielding spatially resolved nematic order parameters, density maps, and bond-orientational order parameters corroborate the universality and robustness of the confinement-induced columnar ring formation as well as its quantized nature.

  18. Thermal stress estimation in relation to spalling of HSC restrained with steel rings at high temperatures

    Directory of Open Access Journals (Sweden)

    Tanibe T.

    2013-09-01

    Full Text Available This paper reports on an experimental study regarding the behavior of steel ring-restrained concrete in response to fire exposure. The study was conducted to enable estimation of thermal stress based on steel ring strain in such concrete under the conditions of a RABT 30 heating curve. The specimens used were made from high-strength concrete (Fc: 80 MPa restrained using steel rings with thicknesses of 0.5, 8 and 18 mm.

  19. The PEP electron-positron ring

    International Nuclear Information System (INIS)

    Rees, J.R.

    1988-01-01

    The first stage of the positron-electron-proton (PEP) colliding-beam system which has been under joint study by a Lawrence Berkeley Laboratory-Stanford Linear Accelerator Center team for the past two years, will be the electron-positron storage ring. The physics justification for the e + e/sup minus/ ring is summarized briefly and the proposed facility is described. The ring will have six arcs having gross radii of about 220 m and six interaction regions located at the centers of straight sections about 130 m long. The longitudinal distance left free for experimental apparatus at the intersection regions will be 20 m. The range of operating beam energies will be from 5 GeV to 15 GeV. The design luminosity at 15 GeV will be 10 32 cm/sup minus 2/s/sup minus 1/, and the luminosity will vary approximately as the square of the beam energy. Alternative methods under consideration for adjusting the beam cross-section are discussed. The designs of the storage ring subsystems and of the conventional facilities including the experimental halls at the interaction regions are described

  20. Bond Energies and Thermochemical Properties of Ring-Opened Diradicals and Carbenes of exo-Tricyclo[5.2.1.0(2,6)]decane.

    Science.gov (United States)

    Hudzik, Jason M; Castillo, Álvaro; Bozzelli, Joseph W

    2015-09-24

    Exo-tricyclo[5.2.1.0(2,6)]decane (TCD) or exo-tetrahydrodicyclopentadiene is an interesting strained ring compound and the single-component high-energy density hydrocarbon fuel known as JP-10. Important initial reactions of TCD at high temperatures could cleave a strained carbon-carbon (C-C) bond in the ring system creating diradicals also constrained by the remaining ring system. This study determines the thermochemical properties of these diradicals (TCD-H2 mJ-nJ where m and n correspond to the cleaved carbons sites) including the carbon-carbon bond dissociation energy (C-C BDE) corresponding to the cleaved TCD site. Thermochemical properties including enthalpies (ΔH°f298), entropies (S(T)), heat capacities (Cp(T)), and C-H and C-C BDEs for the parent (TCD-H2 m-n), radical (TCD-H2 mJ-n and m-nJ), diradical (TCD-H2 mJ-nJ), and carbene (TCD-H2 mJJ-n and m-nJJ) species are determined. Structures, vibrational frequencies, moments of inertia, and internal rotor potentials are calculated at the B3LYP/6-31G(d,p) level of theory. Standard enthalpies of formation in the gas phase for the TCD-H2 m-n parent and radical species are determined using the B3LYP density functional theory and the higher level G3MP2B3 and CBS-QB3 composite methods. For singlet and triplet TCD diradicals and carbenes, M06-2X, ωB97X-D, and CCSD(T) methods are included in the analysis to determine ΔH°f298 values. The C-C BDEs are further calculated using CASMP2(2,2)/aug-cc-pvtz//CASSCF(2,2)/cc-pvtz and with the CASMP2 energies extrapolated to the complete basis set limit. The bond energies calculated with these methods are shown to be comparable to the other calculation methods. Isodesmic work reactions are used for enthalpy analysis of these compounds for effective cancelation of systematic errors arising from ring strain. C-C BDEs range from 77.4 to 84.6 kcal mol(-1) for TCD diradical singlet species. C-H BDEs for the parent TCD-H2 m-n carbon sites range from 93 to 101 kcal mol(-1) with a

  1. The Circular RFQ Storage Ring

    International Nuclear Information System (INIS)

    Ruggiero, A. G.

    1999-01-01

    This paper presents a novel idea of storage ring for the accumulation of intense beams of light and heavy ions at low energy. The new concept is a natural development of the combined features of conventional storage rings and ion traps, and is basically a linear RFQ bent on itself. The advantages are: smaller beam dimensions, higher beam intensity, and a more compact storage device

  2. Hydrogenic-Donor Impurity Binding Energy Dependence of the Electric Field in GaAs/AlxGa1−xAs Quantum Rings

    Directory of Open Access Journals (Sweden)

    Guangxin Wang

    2013-01-01

    Full Text Available Using a variational method with two-parameter trial wave function and the effective mass approximation, the binding energy of a donor impurity in GaAs/AlxGa1−xAs cylindrical quantum ring (QR subjected to an external field is calculated. It is shown that the donor impurity binding energy is highly dependent on the QR structure parameters (radial thickness and height, impurity position, and external electric field. The binding energy increases inchmeal as the QR parameters (radial thickness and height decrease until a maximum value for a central impurity and then begins to drop quickly. The applied electric field can significantly modify the spread of electronic wave function in the QR and shift electronic wave function from the donor position and then leads to binding energy changes. In addition, results for the binding energies of a hydrogenic donor impurity as functions of the impurity position and applied electric field are also presented.

  3. Effective tuning of electron charge and spin distribution in a dot-ring nanostructure at the ZnO interface

    Science.gov (United States)

    Chakraborty, Tapash; Manaselyan, Aram; Barseghyan, Manuk

    2018-05-01

    Electronic states and the Aharonov-Bohm effect in ZnO quantum dot-ring nanostructures containing few interacting electrons reveal several unique features. We have shown here that in contrast to the dot-rings made of conventional semiconductors, such as InAs or GaAs, the dot-rings in ZnO heterojunctions demonstrate several unique characteristics due to the unusual properties of quantum dots and rings in ZnO. In particular the energy spectra of the ZnO dot-ring and the Aharnov-Bohm oscillations are strongly dependant on the electron number in the dot or in the ring. Therefore even small changes of the confinement potential, sizes of the dot-ring or the magnetic field can drastically change the energy spectra and the behavior of Aharonov-Bohm oscillations in the system. Due to this interesting phenomena it is possible to effectively control with high accuracy the electron charge and spin distribution inside the dot-ring structure. This controlling can be achieved either by changing the magnetic field or the confinement potentials.

  4. Using Ring Strain to Control 4π-Electrocyclization Reactions: Torquoselectivity in Ring Closing of Medium-Ring Dienes and Ring Opening of Bicyclic Cyclobutenes.

    Science.gov (United States)

    Boon, Byron A; Green, Aaron G; Liu, Peng; Houk, K N; Merlic, Craig A

    2017-05-05

    Syntheses of strained cyclic dienes were accomplished via palladium(II)-catalyzed oxidative cyclizations of terminal bis(vinylboronate esters). The reactions generate strained (E,E)-1,3-dienes that undergo spontaneous 4π-electrocyclizations to form bicyclic cyclobutenes. Formation of the cyclobutenes is driven by the strain in the medium-ring (E,E)-1,3-diene intermediate. Thermal ring openings of the cyclobutenes give (Z,Z)-1,3-diene products, again for thermodynamic reasons. DFT calculations verified the thermodynamic versus kinetic control of the reactions, and kinetic studies are in excellent agreement with the calculated energy changes. An extension of the tandem coupling/4π-electrocyclization pathway was demonstrated by a palladium(II)-catalyzed oxidative homocoupling/8π-electrocyclization cascade.

  5. Five-membered rings as diazo components in optical data storage devices: An ab initio investigation of the lowest singlet excitation energies

    DEFF Research Database (Denmark)

    Åstrand, P.-O.; Sommer-Larsen, P.; Hvilsted, Søren

    2000-01-01

    been investigated as diazo components for a potential use in optical das storage materials. It is found that the diazo compounds with two heterocyclic five-membered rings have pi --> pi* excitation energies corresponding to laser wavelengths in the region 450-500 nm whereas one five-membered ring...... and a phenyl group as diazo components results in wavelengths in the region 400-335 nm. (C) 2000 Published by Elsevier Science B.V....

  6. Thermodynamic Properties of a Double Ring-Shaped Quantum Dot at Low and High Temperatures

    Science.gov (United States)

    Khordad, R.; Sedehi, H. R. Rastegar

    2018-02-01

    In this work, we study thermodynamic properties of a GaAs double ring-shaped quantum dot under external magnetic and electric fields. To this end, we first solve the Schrödinger equation and obtain the energy levels and wave functions, analytically. Then, we calculate the entropy, heat capacity, average energy and magnetic susceptibility of the quantum dot in the presence of a magnetic field using the canonical ensemble approach. According to the results, it is found that the entropy is an increasing function of temperature. At low temperatures, the entropy increases monotonically with raising the temperature for all values of the magnetic fields and it is independent of the magnetic field. But, the entropy depends on the magnetic field at high temperatures. The entropy also decreases with increasing the magnetic field. The heat capacity and magnetic susceptibility show a peak structure. The heat capacity reduces with increasing the magnetic field at low temperatures. The magnetic susceptibility shows a transition between diamagnetic and paramagnetic below for T<4 K. The transition temperature depends on the magnetic field.

  7. The role of ring current O+ in the formation of stable auroral red arcs

    International Nuclear Information System (INIS)

    Kozyra, J.U.; Cravens, T.E.; Nagy, A.F.; Shelley, E.G.; Comfort, R.H.; Brace, L.H.

    1987-01-01

    Coulomb collisions between ring current protons and thermal electrons were first proposed by Cole (1965) as the energy source for stable auroral red (SAR) arcs. Recent observations have shown that the ring current and magnetospheric plasma contain significant amounts of heavy ions (Johnson et al., 1977; Young et al., 1977; Geiss et al., 1978; and others). In fact, the ring current is often dominated by heavy ions at those energies (E ≤ 17 keV) important for Coulomb collisions on SAR arc field lines (Kozyra et al., 1986a). Observations (during four SAR arcs in 1981) of thermal and energetic ion populations by the Dynamics Explorer 1 satellite in the magnetospheric energy source region and nearly simultaneous Langmuir probe measurements of enhanced electron temperatures by Dynamics Explorer 2 within the SAR arc at F region heights have allowed the authors to examine the role of heavy ions in the formation of SAR arcs. They find that (1) sufficient energy is transferred to the electron gas at high altitudes via Coulomb collisions between the observed ring current ions and thermal electrons to support the enhanced (SAR arc) F region electron temperatures measured on these field lines, (2) the latitudinal variation in the electron heating rates calculated using observed ion populations is consistent with the observed variation in electron temperature across the SAR arc, and (3) in all cases, ring current O + is the major source of energy for the SAR arcs. This implies a relationship between the heavy ion content of the magnetospheric plasma and the occurrence frequency and intensity of SAR arcs

  8. Development Of A Hydrogen And Deuterium Polarized Gas Target For Application In Storage Rings

    International Nuclear Information System (INIS)

    Haeberli, Willy

    2009-01-01

    The exploration of spin degrees of freedom in nuclear and high-energy interactions requires the use of spin-polarized projectiles and/or spin-polarized targets. During the last two decades, the use of external beams from cyclotrons has to a large extent been supplanted by use of circulating beams stored in storage rings. In these experiments, the circulating particles pass millions of times through targets internal to the ring. Thus the targets need to be very thin to avoid beam loss by scattering out of the acceptance aperture of the ring.

  9. High-energy gamma-ray beams from Compton-backscattered laser light

    International Nuclear Information System (INIS)

    Sandorfi, A.M.; LeVine, M.J.; Thorn, C.E.; Giordano, G.; Matone, G.

    1983-01-01

    Collisions of light photons with relativistic electrons have previously been used to produce polarized #betta#-ray beams with modest (-10%) resolution but relatively low intensity. In contrast, the LEGS project (Laser + Electron Gamma Source) at Brookhaven will produce a very high flux (>2 x 10 7 s - 1 ) of background-free polarized #betta# rays whose energy will be determined to a high accuracy (δE = 2.3 MeV). Initially, 300(420)-MeV #betta# rays will be produced by backscattering uv light from the new 2.5(3.0)-GeV X-ray storage ring of the National Synchrotron Light Source (NSLS). The LEGS facility will operate as one of many passive users of the NSLS. In a later stage of the project, a Free Electron Laser is expectred to extend the #betta#-ray energy up to 700 MeV

  10. High-energy gamma-ray beams from Compton-backscattered laser light

    Energy Technology Data Exchange (ETDEWEB)

    Sandorfi, A.M.; LeVine, M.J.; Thorn, C.E.; Giordano, G.; Matone, G.

    1983-01-01

    Collisions of light photons with relativistic electrons have previously been used to produce polarized ..gamma..-ray beams with modest (-10%) resolution but relatively low intensity. In contrast, the LEGS project (Laser + Electron Gamma Source) at Brookhaven will produce a very high flux (>2 x 10/sup 7/ s/sup -1/) of background-free polarized ..gamma.. rays whose energy will be determined to a high accuracy (..delta..E = 2.3 MeV). Initially, 300(420)-MeV ..gamma.. rays will be produced by backscattering uv light from the new 2.5(3.0)-GeV X-ray storage ring of the National Synchrotron Light Source (NSLS). The LEGS facility will operate as one of many passive users of the NSLS. In a later stage of the project, a Free Electron Laser is expectred to extend the ..gamma..-ray energy up to 700 MeV.

  11. The circular RFQ storage ring

    International Nuclear Information System (INIS)

    Ruggiero, A.G.

    1998-01-01

    This paper presents a novel idea of storage ring for the accumulation of intense beams of light and heavy ions at low energy. The new concept is a natural development of the combined features used in a conventional storage ring and an ion trap, and is basically a linear RFQ bend on itself. In summary the advantages are: smaller beam dimensions, higher beam intensity, and a more compact storage device

  12. Study of improvement in 1st ring`s gas-seal; Top ring no gas seal seino kojo no kento

    Energy Technology Data Exchange (ETDEWEB)

    Ando, H; Tateishi, Y; Fujimura, K; Hitosugi, H [Nippon Piston Ring Co. Ltd., Tokyo (Japan)

    1997-10-01

    The authors studied the effect of an angle of 1st ring twist on the amount of blow-by concerning higher speed/higher output engines for motorcycles. As a result, the authors found the twist made the ring restrained in a ring groove of piston , and confirmed its suitable range for blow-by. By means of the developed optimization method, the authors have achieved significant reduction in blow-by at high engine speed. 1 ref., 9 figs., 2 tabs.

  13. Some uses of REPMM's in storage rings and colliders

    International Nuclear Information System (INIS)

    Spencer, J.E.

    1985-04-01

    Improvements for existing rings and techniques for building new rings composed entirely of passive, Rare Earth Permanent Magnet Multipoles (REPMM's) are considered using circular dipoles, quadrupoles and sextupoles. Over the past few years we have made such magnets using a single size SmCo 5 block with up to five easy-axis orientations. The final production scheme is modular in that magnets are built-up from quantized layers. All multipole layers are made in exactly the same way using algorithms differing only by the desired multipole symmetry. The method is simple, efficient and inexpensive and allows a ''do-it-yourself'' approach to constructing new magnetic elements. For rings these might include focusing optical klystrons, rotatable multipoles for diagnostics, correction or extraction, or possibly combined function systems for the unit cells. A high quality, low-beta, PMQ insertion which can change beta, tune and energy is described as well as the PMS's for the SD and SF elements of the North SLC damping ring. Because these sextupoles will be the first optical use of PM's in storage rings they are discussed in detail together with the advantages, problems and requirements of such applications. 8 refs., 4 figs

  14. High frequency electromagnetic characterization of NEG properties for the CLIC damping rings

    CERN Document Server

    Koukovini-Platia, E; Zannini, C

    2014-01-01

    Coating materials will be used in the CLIC damping rings (DR) to suppress two-stream effects. In particular, NEG coating is necessary to suppress fast beam ion instabilities in the electron damping ring (EDR). The electromagnetic (EM) characterization of the material properties up to high frequencies is required for the impedance modeling of the CLIC DR components. The EM properties for frequencies of few GHz are determined with the waveguide method, based on a combination of experimental measurements of the complex transmission coefficient S21 and CST 3D EM simulations. The results obtained from a NEG-coated copper (Cu) waveguide are presented in this paper.

  15. High power ring methods and accelerator driven subcritical reactor application

    Energy Technology Data Exchange (ETDEWEB)

    Tahar, Malek Haj [Univ. of Grenoble (France)

    2016-08-07

    High power proton accelerators allow providing, by spallation reaction, the neutron fluxes necessary in the synthesis of fissile material, starting from Uranium 238 or Thorium 232. This is the basis of the concept of sub-critical operation of a reactor, for energy production or nuclear waste transmutation, with the objective of achieving cleaner, safer and more efficient process than today’s technologies allow. Designing, building and operating a proton accelerator in the 500-1000 MeV energy range, CW regime, MW power class still remains a challenge nowadays. There is a limited number of installations at present achieving beam characteristics in that class, e.g., PSI in Villigen, 590 MeV CW beam from a cyclotron, SNS in Oakland, 1 GeV pulsed beam from a linear accelerator, in addition to projects as the ESS in Europe, a 5 MW beam from a linear accelerator. Furthermore, coupling an accelerator to a sub-critical nuclear reactor is a challenging proposition: some of the key issues/requirements are the design of a spallation target to withstand high power densities as well as ensure the safety of the installation. These two domains are the grounds of the PhD work: the focus is on the high power ring methods in the frame of the KURRI FFAG collaboration in Japan: upgrade of the installation towards high intensity is crucial to demonstrate the high beam power capability of FFAG. Thus, modeling of the beam dynamics and benchmarking of different codes was undertaken to validate the simulation results. Experimental results revealed some major losses that need to be understood and eventually overcome. By developing analytical models that account for the field defects, one identified major sources of imperfection in the design of scaling FFAG that explain the important tune variations resulting in the crossing of several betatron resonances. A new formula is derived to compute the tunes and properties established that characterize the effect of the field imperfections on the

  16. High-power single-mode cw dye ring laser

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, H W; Stein, L; Froelich, D; Fugger, B; Welling, H [Technische Univ. Hannover (Germany, F.R.). Inst. fuer Angewandte Physik

    1977-12-01

    Due to spatial hole burning, standing-wave dye lasers require a large amount of selectivity inside the cavity for single-mode operation. The output power of these lasers is limited by losses caused by the frequency selecting elements. In a travelling-wave laser, on the other hand, spatial hole burning does not exist, thereby eliminating the need for high selectivity. A travelling-wave cw dye laser was realized by unidirectional operation of a ring laser, yielding single mode output powers of 1.2 W at 595 nm and of 55 mW in the UV-region with intracavity frequency doubling.

  17. QED in highly-charged high Z ions - experiments at the storage ring ESR

    International Nuclear Information System (INIS)

    Mokler, P.H.

    1996-01-01

    A survey on the fundamental structure aspects of very heavy few -electron ions, in particular H-like systems, is presented. Special emphasis is given to contribution from quantum-electro-dynamics at strong central potentials. The technical possibilities to produce highly-charged heavy ions are reviewed and the ground-state Lamb-shift experiments performed at the heavy ion storage ring ESR are summarized. A short outlook on further developments in this field is added. (author). 23 refs, 9 figs

  18. Inorganic glass ceramic slip rings

    Science.gov (United States)

    Glossbrenner, E. W.; Cole, S. R.

    1972-01-01

    Prototypes of slip rings have been fabricated from ceramic glass, a material which is highly resistant to deterioration due to high temperature. Slip ring assemblies were not structurally damaged by mechanical tests and performed statisfactorily for 200 hours.

  19. Vertically coupled double quantum rings at zero magnetic field

    OpenAIRE

    Malet, Francesc; Barranco, Manuel; Lipparini, Enrico; Pi, Ricardo Mayol Martí; Climente, Juan Ignacio; Planelles, Josep

    2006-01-01

    Within local-spin-density functional theory, we have investigated the `dissociation' of few-electron circular vertical semiconductor double quantum ring artificial molecules at zero magnetic field as a function of inter-ring distance. In a first step, the molecules are constituted by two identical quantum rings. When the rings are quantum mechanically strongly coupled, the electronic states are substantially delocalized, and the addition energy spectra of the artificial molecule resemble thos...

  20. On the quantitative prediction of bunch lengthening in high energy electron storage rings

    International Nuclear Information System (INIS)

    Weiland, T.

    1981-12-01

    The longitudinal current dependent electromagnetic interaction between a bunch of charged particles and accelerator components can be described by a Green's Function in time domain or by an impedance in frequency domain. The aim of this paper is to describe a procedure which yields an approximate Green's Function for cylindrically symmetric objects. Once this Green's Function is quantitatively known the equation of motion for the particles can be solved easily by a turn-by-turn tracking code on a computer. Thus it is possible to predict the bunch length and width as a function of charge per bunch for future accelerators and storage rings based on pure geometrical data of the accelerator components. Results are presented for PETRA and LEP. A comparison between measurements at PETRA and computations shows an excellent agreement. (orig.)

  1. elegantRingAnalysis An Interface for High-Throughput Analysis of Storage Ring Lattices Using elegant

    CERN Document Server

    Borland, Michael

    2005-01-01

    The code {\\tt elegant} is widely used for simulation of linacs for drivers for free-electron lasers. Less well known is that elegant is also a very capable code for simulation of storage rings. In this paper, we show a newly-developed graphical user interface that allows the user to easily take advantage of these capabilities. The interface is designed for use on a Linux cluster, providing very high throughput. It can also be used on a single computer. Among the features it gives access to are basic calculations (Twiss parameters, radiation integrals), phase-space tracking, nonlinear dispersion, dynamic aperture (on- and off-momentum), frequency map analysis, and collective effects (IBS, bunch-lengthening). Using a cluster, it is easy to get highly detailed dynamic aperture and frequency map results in a surprisingly short time.

  2. Double-Slot Hybrid Plasmonic Ring Resonator Used for Optical Sensors and Modulators

    Directory of Open Access Journals (Sweden)

    Xu Sun

    2015-11-01

    Full Text Available An ultra-high sensitivity double-slot hybrid plasmonic (DSHP ring resonator, used for optical sensors and modulators, is developed. Due to high index contrast, as well as plasmonic enhancement, a considerable part of the optical energy is concentrated in the narrow slots between Si and plasmonic materials (silver is used in this paper, which leads to high sensitivity to the infiltrating materials. By partial opening of the outer plasmonic circular sheet of the DSHP ring, a conventional side-coupled silicon on insulator (SOI bus waveguide can be used. Experimental results demonstrate ultra-high sensitivity (687.5 nm/RIU of the developed DSHP ring resonator, which is about five-times higher than for the conventional Si ring with the same geometry. Further discussions show that a very low detection limit (5.37 × 10−6 RIU can be achieved after loaded Q factor modifications. In addition, the plasmonic metal structures offer also the way to process optical and electronic signals along the same hybrid plasmonic circuits with small capacitance (~0.275 fF and large electric field, which leads to possible applications in compact high-efficiency electro-optic modulators, where no extra electrodes for electronic signals are required.

  3. High resolution upgrade of the ATF damping ring BPM system

    International Nuclear Information System (INIS)

    Terunuma, N.; Urakawa, J.; Frisch, J.; May, J.; McCormick, D.; Nelson, J.; Seryi, A.; Smith, T.; Woodley, M.; Briegel, C.; Dysert, R.

    2008-01-01

    A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility (ATF) damping ring has been accomplished in its first stage, carried out by a KEK/FNAL/SLAC collaboration under the umbrella of the global ILC R and D effort. The upgrade consists of a high resolution, high reproducibility read-out system, based on analog and digital downconversion techniques, digital signal processing, and also tests a new automatic gain error correction schema. The technical concept and realization, as well as preliminary results of beam studies are presented

  4. The Cerenkov ring-imaging detector recent progress and future development

    CERN Document Server

    Ekelöf, T J C; Tocqueville, J; Ypsilantis, Thomas

    1981-01-01

    Results are reported on measurements of Cerenkov ring images using a multistage MWPC with an argon-TEA gas mixture. A specific detector response of N/sub 0/=56 cm/sup -1/ was obtained. It is shown that with some minor modifications to the detector, this value can be raised to N/sub 0/=90 cm/sup -1/. Using an argon-methane-TEA mixture in the MWPC, it is shown that efficient single-photoelectron detection can be achieved with proportional wire amplification without preamplification. A design of a new type of drift chamber (TPC) detector for two-dimensional measurement of the ring image is described. The use of the Cerenkov ring-imaging technique in high- energy physics experimentation is discussed, and in particular a full solid-angle detector for LEP is suggested. (10 refs).

  5. New storage ring at DESY's. HERA's realm in the shades. Pt. 2

    International Nuclear Information System (INIS)

    Habermann, A.

    1987-01-01

    The venture into the smallest dimensions of the microcosm requires gigantic machines. The HERA storage ring, due for completion in 1989, shall help the scientists at DESY in their venture into new realms of high-energy physics. (orig.) [de

  6. Interaction of Vortex Ring with Cutting Plate

    Science.gov (United States)

    Musta, Mustafa

    2015-11-01

    The interaction of a vortex ring impinging on a thin cutting plate was made experimentally using Volumetric 3-component Velocitmetry (v3v) technique. The vortex rings were generated with piston-cylinder vortex ring generator using piston stroke-to-diameter ratios and Re at 2-3 and 1500 - 3000, respectively. The cutting of vortex rings below center line leads to the formation of secondary vortices on each side of the plate which is look like two vortex rings, and a third vortex ring propagates further downstream in the direction of the initial vortex ring, which is previously showed by flow visualization study of Weigand (1993) and called ``trifurcation''. Trifurcation is very sensitive to the initial Reynolds number and the position of the plate with respect to the vortex ring generator pipe. The present work seeks more detailed investigation on the trifurcation using V3V technique. Conditions for the formation of trifurcation is analyzed and compared with Weigand (1993). The formed secondary vortex rings and the propagation of initial vortex ring in the downstream of the plate are analyzed by calculating their circulation, energy and trajectories.

  7. Polarization Studies for the eRHIC Electron Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Gianfelice-Wendt, Eliana [Fermilab; Tepikian, S. [Brookhaven

    2018-04-01

    A hadron/lepton collider with polarized beams has been under consideration by the scientific community since some years, in the U.S. and Europe. Among the various proposals, those by JLAB and BNL with polarized electron and proton beams are currently under closer study in the U.S. Experimenters call for the simultaneous storage of electron bunches with both spin helicity. In the BNL based Ring-Ring design, electrons are stored at top energy in a ring to be accommodated in the existing RHIC tunnel. The transversely polarized electron beam is injected into the storage ring at variable energies, between 5 and 18 GeV. Polarization is brought into the longitudinal direction at the IP by a couple of spin rotators. In this paper results of first studies of the attainable beam polarization level and lifetime in the storage ring at 18 GeV are presented.

  8. Compressible Vortex Ring

    Science.gov (United States)

    Elavarasan, Ramasamy; Arakeri, Jayawant; Krothapalli, Anjaneyulu

    1999-11-01

    The interaction of a high-speed vortex ring with a shock wave is one of the fundamental issues as it is a source of sound in supersonic jets. The complex flow field induced by the vortex alters the propagation of the shock wave greatly. In order to understand the process, a compressible vortex ring is studied in detail using Particle Image Velocimetry (PIV) and shadowgraphic techniques. The high-speed vortex ring is generated from a shock tube and the shock wave, which precedes the vortex, is reflected back by a plate and made to interact with the vortex. The shadowgraph images indicate that the reflected shock front is influenced by the non-uniform flow induced by the vortex and is decelerated while passing through the vortex. It appears that after the interaction the shock is "split" into two. The PIV measurements provided clear picture about the evolution of the vortex at different time interval. The centerline velocity traces show the maximum velocity to be around 350 m/s. The velocity field, unlike in incompressible rings, contains contributions from both the shock and the vortex ring. The velocity distribution across the vortex core, core diameter and circulation are also calculated from the PIV data.

  9. High Astrometric Precision in the Calculation of the Coordinates of Orbiters in the GEO Ring

    Science.gov (United States)

    Lacruz, E.; Abad, C.; Downes, J. J.; Hernández-Pérez, F.; Casanova, D.; Tresaco, E.

    2018-04-01

    We present an astrometric method for the calculation of the positions of orbiters in the GEO ring with a high precision, through a rigorous astrometric treatment of observations with a 1-m class telescope, which are part of the CIDA survey of the GEO ring. We compute the distortion pattern to correct for the systematic errors introduced by the optics and electronics of the telescope, resulting in absolute mean errors of 0.16″ and 0.12″ in right ascension and declination, respectively. These correspond to ≍25 m at the mean distance of the GEO ring, and are thus good quality results.

  10. Reducing support loss in micromechanical ring resonators using phononic band-gap structures

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Feng-Chia; Huang, Tsun-Che; Wang, Chin-Hung; Chang, Pin [Industrial Technology Research Institute-South, Tainan 709, Taiwan (China); Hsu, Jin-Chen, E-mail: fengchiahsu@itri.org.t, E-mail: hsujc@yuntech.edu.t [Department of Mechanical Engineering, National Yunlin University of Science and Technology, Douliou, Yunlin 64002, Taiwan (China)

    2011-09-21

    In micromechanical resonators, energy loss via supports into the substrates may lead to a low quality factor. To eliminate the support loss, in this paper a phononic band-gap structure is employed. We demonstrate a design of phononic-crystal (PC) strips used to support extensional wine-glass mode ring resonators to increase the quality factor. The PC strips are introduced to stop elastic-wave propagation by the band-gap and deaf-band effects. Analyses of resonant characteristics of the ring resonators and the dispersion relations, eigenmodes, and transmission properties of the PC strips are presented. With the proposed resonator architecture, the finite-element simulations show that the leaky power is effectively reduced and the stored energy inside the resonators is enhanced simultaneously as the operating frequencies of the resonators are within the band gap or deaf bands. Realization of a high quality factor micromechanical ring resonator with minimized support loss is expected.

  11. Reducing support loss in micromechanical ring resonators using phononic band-gap structures

    International Nuclear Information System (INIS)

    Hsu, Feng-Chia; Huang, Tsun-Che; Wang, Chin-Hung; Chang, Pin; Hsu, Jin-Chen

    2011-01-01

    In micromechanical resonators, energy loss via supports into the substrates may lead to a low quality factor. To eliminate the support loss, in this paper a phononic band-gap structure is employed. We demonstrate a design of phononic-crystal (PC) strips used to support extensional wine-glass mode ring resonators to increase the quality factor. The PC strips are introduced to stop elastic-wave propagation by the band-gap and deaf-band effects. Analyses of resonant characteristics of the ring resonators and the dispersion relations, eigenmodes, and transmission properties of the PC strips are presented. With the proposed resonator architecture, the finite-element simulations show that the leaky power is effectively reduced and the stored energy inside the resonators is enhanced simultaneously as the operating frequencies of the resonators are within the band gap or deaf bands. Realization of a high quality factor micromechanical ring resonator with minimized support loss is expected.

  12. High-latitude tree-ring data: Records of climatic change and ecological response

    International Nuclear Information System (INIS)

    Graumlich, L.J.

    1991-01-01

    Tree-ring data provide critical information regarding two fundamental questions as to the role of the polar regions in global change: (1) what is the nature of climatic variability? and (2) what is the response of vegetation to climatic variability? Tree-ring-based climatic reconstructions document the variability of the climate system on time scales of years to centuries. Dendroclimatic reconstructions indicate that the climatic episodes defined on the basis of documentary evidence in western Europe (i.e., Medieval Warm Episode, ca. A.D. 1000-1300; Little Ice Age, ca. A.D. 1550-1850) can be observed at some high-latitude sites (ex., Polar Urals). Spatial variation in long-term temperature trends (ex., northern Fennoscandia vs. Polar Urals) demonstrates the importance of regional-scale climatic controls. When collated into global networks, proxy-based climatic reconstructions can be used to test hypotheses as to the relative importance of external forcing vs. internal variation in governing climatic variation. Specifically, such a global network would allow the quantification of the climatic response to various permutations of factors thought to be important in governing decadal- to centennial-scale climatic variation. Tree populations respond to annual- to centennial-scale climatic variation through changes in rates of growth, establishment, and mortality. Tree-ring studies that document multiple aspects of high-latitude treeline dynamics (i.e., the timing of tree establishment, mortality, and changes from krummholz to upright growth) indicate a complex interaction between growth form, population processes, and environmental variability. Such interactions result in varying sensitivities of high-latitude trees to climatic change

  13. Application research of ferrous matrix composites in roller ring used in high-speed wire/bar rolling mill

    International Nuclear Information System (INIS)

    Song Yanpei; Li Xiuqing; Bi Shuangxu

    2010-01-01

    Research highlights: → A composite structure roller rings was fabricated by centrifugal casting. → The roller rings consisted of outer WCP/Fe-C composites layer and inner Fe-C alloy matrix. → Hardness attained to HRA80-85 in the composites layer, and HRA73-76 in inner Fe-C alloy matrix where the toughness was over 8 J/cm 2 . → The wear resistance of the roller rings excelled that of high-speed steel, and approached to that of the WC hard alloy roll. → The production cost of the WCP/Fe-C composites roller ring decreased by 50%. - Abstract: Tungsten carbide particle (WC P ) reinforced ferrous matrix composites roller rings were fabricated by centrifugal casting. The microstructures, properties and application effect of the composites roller rings were investigated by SEM, TEM and various property testers. The experimental results show that the WC P were uniformly distributed in outer reinforced-layer (working-layer) of 20-50 mm in thickness and their volume fraction reached 60-80 vol.%; there was a good interface bonding between WC P and Fe-C alloy without any reaction products; hardness attained to HRA80-85 in working-layer, and HRA73-76 in inner ferrous matrix where the toughness was over 8 J/cm 2 ; the wear resistance of the composites roller rings excels that of high-speed steel; service life of the composites parts approached to that of the WC hard alloy roll when the same WC P -volume-fraction in working-layer were obtained for both of them, but the production cost of the WC P /Fe-C composites roller ring decreased by 50%.

  14. Development of high-power and high-energy 2 µm bulk solid-state lasers and amplifiers

    CSIR Research Space (South Africa)

    Koen, W

    2016-04-01

    Full Text Available 250 300 350 Pulse Repetition Frequency [Hz] P u l s e E n e r g y [ m J ] 0 1 2 3 4 5 6 7 8 9 10 A v e r a g e P o w e r [ W ] Osc Energy Amp Energy Osc average P Amp average P Figure 8: Output energy of the ring laser and amplifier...

  15. 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.

  16. Novel miniature high power ring filter

    International Nuclear Information System (INIS)

    Huang Huifen; Mao Junfa; Luo Zhihua

    2005-01-01

    The power handling capability of high temperature superconducting (HTS) filters is limited due to current concentration at the edges of the superconducting films. This problem can be overcome by using ring resonator, which employs the edge current free and reduces the current concentration. However, this kind of filter has large size. In order to reduce the cost and size and increase the power handling capability, in this paper a HTS photonic bandgap (PBG) structure filter is developed. The proposed pass band filter with PBG structure exhibits center frequency 12.23 GHz, steepness (about 35 dB/GHz), bandwidth (-3 dB bandwidth is 0.045 GHz), and low insertion loss (about -0.5 dB), and can handle input power up to 1 W (this value was limited by the measurement instrument used in the experiment). The size is reduced by 25%, insertion loss reduced by 37.5%, and steeper roll-off of the filter is also obtained compared with that in published literature

  17. High-Frequency Oscillations Recorded on the Scalp of Patients With Epilepsy Using Tripolar Concentric Ring Electrodes.

    Science.gov (United States)

    Besio, Walter G; Martínez-Juárez, Iris E; Makeyev, Oleksandr; Gaitanis, John N; Blum, Andrew S; Fisher, Robert S; Medvedev, Andrei V

    2014-01-01

    Epilepsy is the second most prevalent neurological disorder ([Formula: see text]% prevalence) affecting [Formula: see text] million people worldwide with up to 75% from developing countries. The conventional electroencephalogram is plagued with artifacts from movements, muscles, and other sources. Tripolar concentric ring electrodes automatically attenuate muscle artifacts and provide improved signal quality. We performed basic experiments in healthy humans to show that tripolar concentric ring electrodes can indeed record the physiological alpha waves while eyes are closed. We then conducted concurrent recordings with conventional disc electrodes and tripolar concentric ring electrodes from patients with epilepsy. We found that we could detect high frequency oscillations, a marker for early seizure development and epileptogenic zone, on the scalp surface that appeared to become more narrow-band just prior to seizures. High frequency oscillations preceding seizures were present in an average of 35.5% of tripolar concentric ring electrode data channels for all the patients with epilepsy whose seizures were recorded and absent in the corresponding conventional disc electrode data. An average of 78.2% of channels that contained high frequency oscillations were within the seizure onset or irritative zones determined independently by three epileptologists based on conventional disc electrode data and videos.

  18. Ring wormholes via duality rotations

    Directory of Open Access Journals (Sweden)

    Gary W. Gibbons

    2016-09-01

    Full Text Available We apply duality rotations and complex transformations to the Schwarzschild metric to obtain wormhole geometries with two asymptotically flat regions connected by a throat. In the simplest case these are the well-known wormholes supported by phantom scalar field. Further duality rotations remove the scalar field to yield less well known vacuum metrics of the oblate Zipoy–Voorhees–Weyl class, which describe ring wormholes. The ring encircles the wormhole throat and can have any radius, whereas its tension is always negative and should be less than −c4/4G. If the tension reaches the maximal value, the geometry becomes exactly flat, but the topology remains non-trivial and corresponds to two copies of Minkowski space glued together along the disk encircled by the ring. The geodesics are straight lines, and those which traverse the ring get to the other universe. The ring therefore literally produces a hole in space. Such wormholes could perhaps be created by negative energies concentrated in toroidal volumes, for example by vacuum fluctuations.

  19. Energy of Intramolecular Hydrogen Bonding in ortho-Hydroxybenzaldehydes, Phenones and Quinones. Transfer of Aromaticity from ipso-Benzene Ring to the Enol System(s

    Directory of Open Access Journals (Sweden)

    Danuta Rusinska-Roszak

    2017-03-01

    Full Text Available Intramolecular hydrogen bonding (HB is one of the most studied noncovalent interactions of molecules. Many physical, spectral, and topological properties of compounds are under the influence of HB, and there are many parameters used to notice and to describe these changes. Hitherto, no general method of measurement of the energy of intramolecular hydrogen bond (EHB has been put into effect. We propose the molecular tailoring approach (MTA for EHB calculation, modified to apply it to Ar-O-H∙∙∙O=C systems. The method, based on quantum calculations, was checked earlier for hydroxycarbonyl-saturated compounds, and for structures with resonance-assisted hydrogen bonding (RAHB. For phenolic compounds, the accuracy, repeatability, and applicability of the method is now confirmed for nearly 140 structures. For each structure its aromaticity HOMA indices were calculated for the central (ipso ring and for the quasiaromatic rings given by intramolecular HB. The comparison of calculated HB energies and values of estimated aromaticity indices allowed us to observe, in some substituted phenols and quinones, the phenomenon of transfer of aromaticity from the ipso-ring to the H-bonded ring via the effect of electron delocalization.

  20. Inelastic magnetic scattering of polarized neutrons by a superconducting ring

    International Nuclear Information System (INIS)

    Agafonov, A. I.

    2011-01-01

    The inelastic scattering of cold neutrons by a ring leads to quantum jumps of a superconducting current which correspond to a decrease in the fluxoid quantum number by one or several units while the change in the ring energy is transferred to the kinetic energy of the scattered neutron. The scattering cross sections of transversely polarized neutrons have been calculated for a thin type-II superconductor ring, the thickness of which is smaller than the field penetration depth but larger than the electron mean free path.

  1. Wear Analysis of Top Piston Ring to Reduce Top Ring Reversal Bore Wear

    Directory of Open Access Journals (Sweden)

    P. Ilanthirayan

    2017-12-01

    Full Text Available The piston rings are the most important part in engine which controls the lubricating oil consumption and blowby of the gases. The lubricating film of oil is provided to seal of gases towards crankcase and also to give smooth friction free translatory motion between rings and liner. Of the three rings present top ring is more crucial as it does the main work of restricting gases downwards the crankcase. Boundary lubrication is present at the Top dead centre (TDC and Bottom dead centre (BDC of the liner surface. In addition to this, top ring is exposed to high temperature gases which makes the oil present near the top ring to get evaporated and decreasing its viscosity, making metal-metal contact most of the time. Due to this at TDC, excess wear happens on the liner which is termed as Top ring reversal bore wear. The wear rate depends upon many parameters such as lubrication condition, viscosity index, contact type, normal forces acting on ring, geometry of ring face, surface roughness, material property. The present work explores the wear depth for different geometries of barrel ring using Finite Element model with the help of Archard wear law and the same is validated through experimentation. The study reveals that Asymmetric barrel rings have less contact pressure which in turn reduces the wear at Top dead centre.

  2. Plasmonic Refractive Index Sensor with High Figure of Merit Based on Concentric-Rings Resonator

    Science.gov (United States)

    Zhang, Zhaojian; Yang, Junbo; He, Xin; Zhang, Jingjing; Huang, Jie; Chen, Dingbo; Han, Yunxin

    2018-01-01

    A plasmonic refractive index (RI) sensor based on metal-insulator-metal (MIM) waveguide coupled with concentric double rings resonator (CDRR) is proposed and investigated numerically. Utilizing the novel supermodes of the CDRR, the FWHM of the resonant wavelength can be modulated, and a sensitivity of 1060 nm/RIU with high figure of merit (FOM) 203.8 is realized in the near-infrared region. The unordinary modes, as well as the influence of structure parameters on the sensing performance, are also discussed. Such plasmonic sensor with simple framework and high optical resolution could be applied to on-chip sensing systems and integrated optical circuits. Besides, the special cases of bio-sensing and triple rings are also discussed. PMID:29300331

  3. Investigation and optimization of transverse non-linear beam dynamics in the high-energy storage ring HESR

    Energy Technology Data Exchange (ETDEWEB)

    Welsch, Dominic Markus

    2010-03-10

    The High-Energy Storage Ring (HESR) is part of the upcoming Facility for Antiproton and Ion Research (FAIR) which is planned as a major extension to the present facility of the Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt. The HESR will provide antiprotons in the momentum range from 1.5 to 15 GeV/c for the internal target experiment PANDA. The demanding requirements of PANDA in terms of beam quality and luminosity together with a limited production rate of antiprotons call for a long beam life time and a minimum of beam loss. Therefore, an effective closed orbit correction and a sufficiently large dynamic aperture of the HESR are crucial. With this thesis I present my work on both of these topics. The expected misalignments of beam guiding magnets have been estimated and used to simulate the closed orbit in the HESR. A closed orbit correction scheme has been developed for different ion optical settings of the HESR and numerical simulations have been performed to validate the scheme. The proposed closed orbit correction method which uses the orbit response matrix has been benchmarked at the Cooler Synchrotron COSY of the Forschungszentrum Juelich. A chromaticity correction scheme for the HESR consisting of sextupole magnets has been developed to reduce tune spread and thus to minimize the emittance growth caused by betatron resonances. The chromaticity correction scheme has been optimized through dynamic aperture calculations. The estimated field errors of the HESR dipole and quadrupole magnets have been included in the non-linear beam dynamics studies. Investigations concerning their optimization have been carried out. The ion optical settings of the HESR have been improved using dynamic aperture calculations and the technique of frequency map analysis. The related diffusion coefficient was also used to predict long-term stability based on short-term particle tracking. With a reasonable reduction of the quadrupole magnets field errors and a

  4. Low energy ring lattice of the PEP-II asymmetric B-Factory

    International Nuclear Information System (INIS)

    Cai, Y.; Donald, M.; Helm, R.; Irwin, J.; Nosochkov, Y.; Ritson, D.M.; Yan, Y.

    1995-01-01

    Developing a lattice that contains a very low beta value at the interaction point (IP) and has adequate dynamic aperture is one of the major challenges in designing the PEP-II asymmetric B-factory. For the Low Energy Ring (LER) the authors have studied several different chromatic correction schemes since the conceptual design report (CDR). Based on these studies, a hybrid solution with local and semi-local chromatic sextupoles has been selected as the new baseline lattice to replace the local scheme in the CDR. The new design simplifies the interaction region (IR) and reduces the number of sextupoles in the arcs. Arc sextupoles are paired at π phase difference and are not interleaved. In this paper the authors describe the baseline lattice with the emphasis on the lattice changes made since the CDR

  5. Mechanochemical Ring-Opening Polymerization of Lactide: Liquid-Assisted Grinding for the Green Synthesis of Poly(lactic acid) with High Molecular Weight.

    Science.gov (United States)

    Ohn, Nuri; Shin, Jihoon; Kim, Sung Sik; Kim, Jeung Gon

    2017-09-22

    Mechanochemical polymerization of lactide is carried out by using ball milling. Mechanical energy from collisions between the balls and the vessel efficiently promotes an organic-base-mediated metal- and solvent-free solid-state polymerization. Investigation of the parameters of the ball-milling synthesis revealed that the degree of lactide ring-opening polymerization could be modulated by the ball-milling time, vibration frequency, mass of the ball media, and liquid-assisted grinding. Liquid-assisted grinding was found to be an especially important factor for achieving a high degree of mechanochemical polymerization. Although polymer-chain scission from the strong collision energy prevented mechanical-force-driven high-molecular-weight polymer synthesis, the addition of only a small amount of liquid enabled sufficient energy dissipation and poly(lactic acid) was thereby obtained with a molecular weight of over 1×10 5  g mol -1 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Design for a practical, low-emittance damping ring

    International Nuclear Information System (INIS)

    Krejcik, P.

    1988-01-01

    The luminosity requirements for future high-energy linear colliders calls for very low emittances in the two beams. These low emittances can be achieved with damping rings, but, in order to reach the design goal of a factor 10 improvement over present day machines, great care must be taken in their design. This paper emphasizes the need to address simultaneously all of the factors which limit the operational emittance in the ring. Particularly since in standard designs there is a conflict between different design parameters which makes it difficult to extrapolate such designs to very low emittances. The approach chosen here is to resolve such conflicts by separating their design solutions. Wigglers are used predominantly in zero-dispersion regions to achieve the desired damping rate, whereas in the arcs high dispersion insertions are made in regions of zero curvature to allow for easier chromaticity control

  7. Electronic properties of superlattices on quantum rings.

    Science.gov (United States)

    da Costa, D R; Chaves, A; Ferreira, W P; Farias, G A; Ferreira, R

    2017-04-26

    We present a theoretical study of the one-electron states of a semiconductor-made quantum ring (QR) containing a series of piecewise-constant wells and barriers distributed along the ring circumference. The single quantum well and the superlattice cases are considered in detail. We also investigate how such confining potentials affect the Aharonov-Bohm like oscillations of the energy spectrum and current in the presence of a magnetic field. The model is simple enough so as to allow obtaining various analytical or quasi-analytical results. We show that the well-in-a-ring structure presents enhanced localization features, as well as specific geometrical resonances in its above-barrier spectrum. We stress that the superlattice-in-a-ring structure allows giving a physical meaning to the often used but usually artificial Born-von-Karman periodic conditions, and discuss in detail the formation of energy minibands and minigaps for the circumferential motion, as well as several properties of the superlattice eigenstates in the presence of the magnetic field. We obtain that the Aharonov-Bohm oscillations of below-barrier miniband states are reinforced, owing to the important tunnel coupling between neighbour wells of the superlattice, which permits the electron to move in the ring. Additionally, we analysis a superlattice-like structure made of a regular distribution of ionized impurities placed around the QR, a system that may implement the superlattice in a ring idea. Finally, we consider several random disorder models, in order to study roughness disorder and to tackle the robustness of some results against deviations from the ideally nanostructured ring system.

  8. Moving ring reactor 'Karin-1'

    International Nuclear Information System (INIS)

    1983-12-01

    The conceptual design of a moving ring reactor ''Karin-1'' has been carried out to advance fusion system design, to clarify the research and development problems, and to decide their priority. In order to attain these objectives, a D-T reactor with tritium breeding blanket is designed, a commercial reactor with net power output of 500 MWe is designed, the compatibility of plasma physics with fusion engineering is demonstrated, and some other guideline is indicated. A moving ring reactor is composed mainly of three parts. In the first formation section, a plasma ring is formed and heated up to ignition temperature. The plasma ring of compact torus is transported from the formation section through the next burning section to generate fusion power. Then the plasma ring moves into the last recovery section, and the energy and particles of the plasma ring are recovered. The outline of a moving ring reactor ''Karin-1'' is described. As a candidate material for the first wall, SiC was adopted to reduce the MHD effect and to minimize the interaction with neutrons and charged particles. The thin metal lining was applied to the SiC surface to solve the problem of the compatibility with lithium blanket. Plasma physics, the engineering aspect and the items of research and development are described. (Kako, I.)

  9. Optical control of spin-dependent thermal transport in a quantum ring

    Science.gov (United States)

    Abdullah, Nzar Rauf

    2018-05-01

    We report on calculation of spin-dependent thermal transport through a quantum ring with the Rashba spin-orbit interaction. The quantum ring is connected to two electron reservoirs with different temperatures. Tuning the Rashba coupling constant, degenerate energy states are formed leading to a suppression of the heat and thermoelectric currents. In addition, the quantum ring is coupled to a photon cavity with a single photon mode and linearly polarized photon field. In a resonance regime, when the photon energy is approximately equal to the energy spacing between two lowest degenerate states of the ring, the polarized photon field can significantly control the heat and thermoelectric currents in the system. The roles of the number of photon initially in the cavity, and electron-photon coupling strength on spin-dependent heat and thermoelectric currents are presented.

  10. Electron transmission through coupled quantum dots in an Aharonov-Bohm ring

    International Nuclear Information System (INIS)

    Joe, Y. S.; Kim, Y. D.

    2006-01-01

    Stimulated by recent intriguing experiments with a quantum dot in an Aharonov-Bohm (AB) ring, we investigate novel resonant phenomena by studying the total transmission probability of nanoscale AB ring with embedded double quantum dots in one arm and a magnetic flux passing through the rings' center. In this system, we show an overlapping and merging of Fano resonances as the interaction parameter between the dots changes. In the strong overlapping region of Fano resonances, the transmission zeros leave the real-energy axis and move away in opposite directions in the complex-energy plane. The behavior of the Fano zero-pole resonances in the complex-energy plane as a function of the external magnetic flux is also investigated for various coupling integrals between the quantum dots in the ring.

  11. Two Electron States in a Quantum Ring on a Sphere

    International Nuclear Information System (INIS)

    Kazaryan, Eduard M.; Shahnazaryan, Vanik A.; Sarkisyan, Hayk A.

    2014-01-01

    Two electron states in a quantum ring on a spherical surface are discussed. The problem is discussed within the frameworks of Russell–Saunders coupling scheme, that is, the spin–orbit coupling is neglected. Treating Coulomb interaction as a perturbation, the energy correction for different states is calculated. The dependence of the Coulomb interaction energy on external polar boundary angle of quantum ring is obtained. In analogue with the helium atom the concept of states exchange time is introduced, and its dependence on geometrical parameters of the ring is shown. (author)

  12. Quasilocal equilibrium condition for black ring

    International Nuclear Information System (INIS)

    Astefanesei, Dumitru; Rodriguez, Maria J.; Theisen, Stefan

    2009-01-01

    We use the conservation of the renormalized boundary stress-energy tensor to obtain the equilibrium condition for a general (thin or fat) black ring solution. We also investigate the role of the spatial stress in the thermodynamics of deformation within the quasilocal formalism of Brown and York and discuss the relation with other methods. In particular, we discuss the quantum statistical relation for the unbalanced black ring solution.

  13. Assembly of silver nanowire ring induced by liquid droplet

    Science.gov (United States)

    Seong, Baekhoon; Park, Hyun Sung; Chae, Ilkyeong; Lee, Hyungdong; Wang, Xiaofeng; Jang, Hyung-Seok; Jung, Jaehyuck; Lee, Changgu; Lin, Liwei; Byun, Doyoung

    2017-11-01

    Several forces in the liquid droplet drive the nanomaterials to naturally form an assembled structure. During evaporation of a liquid droplet, nanomaterials can move to the rim of the droplet by convective flow and capillary flow, due to the difference in temperature between the top and contact line of the droplet. Here, we demonstrate a new, simple and scalable technology for the fabrication of ring-shaped Ag NWs by a spraying method. We experimentally identify the compressive force of the droplet driven by surface tension as the key mechanism for the self-assembly of ring structures. We investigated the progress of ring shape formation of Ag NWs according to the droplet size with theoretically calculated optimal conditions. As such, this self-assembly technique of making ring-shaped structures from Ag NWs could be applied to other nanomaterials. This work was supported by the New & Renewable Energy R&D program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) Grant funded by the Korea government Ministry of Trade, Industry and Energy. (No. 20163010071630).

  14. Powder metallurgy ferrous synchronizer ring with brass-based friction layer; Tetsu-do niso shoketsu synchronize ring no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Okajima, H; Yoshikawa, K; Miyajima, K; Sugiyama, M [Toyota Motor Corp., Aichi (Japan); Nakamura, M; Ito, M [Japan Powder Metallurgy Co. Ltd., Tokyo (Japan)

    1997-10-01

    Synchronizer rings for manual transmissions are generally made of brass or molybdenum coated brass. Powder metallurgy (PM) synchronizer ring was developed for the purpose of high performance and cost reduction. This synchronizer ring consists of the high strength PM ferrous ring that needs neither special densification nor heat treatment, and it has the brass-based friction layer. New joining technique was required because of that shape and two different materials. Powder of copper-phosphorus alloy are admixed with the friction material. While sintering, that melt and migrate to the interface. Then the friction layer and the ferrous ring are joined tightly. 7 refs., 9 figs., 6 tabs.

  15. Nonlinear interaction of colliding beams in particle storage rings

    International Nuclear Information System (INIS)

    Herrera, J.C.; Month, M.

    1979-01-01

    When two beams of high energy particles moving in opposite directions are brought into collision, a large amount of energy is available for the production of new particles. However to obtain a sufficiently high event rate for rare processes, such as the production of the intermediate vector boson (Z 0 and W +- ), large beam currents are also required. Under this circumstance, the high charge density of one beam results in a classical electromagnetic interaction on the particles in the other beam. This very nonlinear space charge force, caled the beam-beam force, limits the total circulating charge and, thereby, the ultimate performance of the colliding ring system. The basic nature of the beam-beam force is discussed, indicating how it is quite different in the case of continuous beams, which cross each other at an angle as compared to the case of bunched beams which collide head-on. Some experimental observations on the beam-beam interaction in proton-proton and electron-positron beams are then reviewed and interpreted. An important aspect of the beam-beam problem in storage rings is to determine at what point in the analysis of the particle dynamics is it relevant to bring in the concepts of stochasticity, slow diffusion, and resonance overlap. These ideas are briefly discussed

  16. Lattice design for the CEPC double ring scheme

    Science.gov (United States)

    Wang, Yiwei; Su, Feng; Bai, Sha; Zhang, Yuan; Bian, Tianjian; Wang, Dou; Yu, Chenghui; Gao, Jie

    2018-01-01

    A future Circular Electron Positron Collider (CEPC) has been proposed by China with the main goal of studying the Higgs boson. Its baseline design, chosen on the basis of its performance, is a double ring scheme; an alternative design is a partial double ring scheme which reduces the budget while maintaining an adequate performance. This paper will present the collider ring lattice design for the double ring scheme. The CEPC will also work as a W and a Z factory. For the W and Z modes, except in the RF region, compatible lattices were obtained by scaling down the magnet strength with energy.

  17. Fundamental Design Principles of Linear Collider Damping Rings, with an Application to CLIC

    CERN Document Server

    Potier, J P

    2000-01-01

    Damping Rings for Linear Colliders have to produce very small normalised emittances at a high repetition rate. A previous paper presented analytical expressions for the equilibrium emittance of an arc cell as a function of the deflection angle per dipole. In addition, an expression for the lattice parameters providing the minimum emittance, and a strategy to stay close to this, were proposed. This analytical approach is extended to the detailed design of Damping Rings, taking into account the straight sections and the damping wigglers. Complete rings, including wiggler and injection insections, were modelled with the MAD [1] program, and their performance was found to be in good agreement with the analytical calculation. With such an approach it is shown that a Damping Ring corresponding to the Compact Linear Collider (CLIC) parameters at 0.5 and 1 TeV centre-of-mass energy, and tunable for two different sets of emittance and injection repetition rate, can be designed using the same ring layout.

  18. Intermediate-range order in mesoporous silicas investigated by a high-energy X-ray diffraction technique

    International Nuclear Information System (INIS)

    Wakihara, Toru; Fan, Wei; Ogura, Masaru; Okubo, Tatsuya; Kohara, Shinji; Sankar, Gopinathan

    2008-01-01

    We perform a high-energy X-ray diffraction study comparing bulk amorphous silica with MCM-41 and SBA-15 that are representative mesoporous silicas prepared in basic and acidic conditions, respectively. It is revealed that mesoporous silicas, especially SBA-15, have less ordered structures and contain larger fractions of three- and four-membered rings than does bulk amorphous silica. (author)

  19. ORBIT: A CODE FOR COLLECTIVE BEAM DYNAMICS IN HIGH INTENSITY RINGS

    International Nuclear Information System (INIS)

    HOLMES, J.A.; DANILOV, V.; GALAMBOS, J.; SHISHLO, A.; COUSINEAU, S.; CHOU, W.; MICHELOTTI, L.; OSTIGUY, J.F.; WEI, J.

    2002-01-01

    We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection, including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK, the introduction of a treatment of magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings

  20. ORBIT: A Code for Collective Beam Dynamics in High-Intensity Rings

    Science.gov (United States)

    Holmes, J. A.; Danilov, V.; Galambos, J.; Shishlo, A.; Cousineau, S.; Chou, W.; Michelotti, L.; Ostiguy, J.-F.; Wei, J.

    2002-12-01

    We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection, including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK; the introduction of a treatment of magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings.

  1. ORBIT: A code for collective beam dynamics in high-intensity rings

    International Nuclear Information System (INIS)

    Holmes, J.A.; Danilov, V.; Galambos, J.; Shishlo, A.; Cousineau, S.; Chou, W.; Michelotti, L.; Ostiguy, J.-F.; Wei, J.

    2002-01-01

    We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection, including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK; the introduction of a treatment of magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings

  2. Measurement of spin motions in a storage ring outside the stable polarization direction

    International Nuclear Information System (INIS)

    Akchurin, N.; Badano, L.; Bravar, A.; Istituto Nazionale di Fisica Nucleare, Legnaro

    1993-06-01

    Polarized, stored beams are becoming a more and more important tool in nuclear and high energy physics. In order to measure the beam polarization in a storage ring the polarization vector of the stored beams has to aim, revolution for revolution, over a period of seconds to minutes, into the same, so-called ''stable'' direction. In this paper measurements at the Indiana University cooler ring (IUCF) are described in which for the first time in a storage ring oscillations of the polarization vector around this stable direction have been measured. The existence and the dynamics of such oscillations are, for instance, important for a new proposed technique for polarizing stored hadron beams

  3. Measurement of spin motions in a storage ring outside the stable polarization direction

    International Nuclear Information System (INIS)

    Akchurin, N.; McPherson, J.; Olchowski, F.; Onel, Y.; Badano, L.; Conte, M.; Bravar, A.; Penzo, A.; Hall, J.; Kreiser, H.

    1993-01-01

    Polarized, stored beams are becoming a more and more important tool in nuclear and high energy physics. In order to measure the beam polarization in a storage ring the polarization vector of the stored beam has to aim, revolution for revolution, over a period of seconds to minutes, into the same, so-called open-quote stableclose quotes, direction. In this paper measurements at the Indiana University Cooler Ring (IUCF) are described in which for the first time in a storage ring oscillations of the polarization vector around this stable direction have been measured. The existence and the dynamics of such oscillations are, for instance, important for a new proposed technique for polarizing stored hadron beams

  4. Superconducting proton ring for PETRA

    International Nuclear Information System (INIS)

    Baynham, E.

    1979-01-01

    A powerful new facility for colliding beam physics could be provided by adding a proton storage ring in the range of several hundred GeV to the electron-positron storage ring PETRA at DESY. This can be achieved in an economic way utilizing the PETRA tunnel and taking advantage of the higher magnetic fields of superconducting magnets which would be placed above or below the PETRA magnets. A central field of 4 Tesla in the bending magnets corresponds to a proton energy of 225 GeV. (orig.)

  5. Non-linear transverse dynamics for storage rings with application to the low-energy antiproton ring (LEAR) at CERN

    International Nuclear Information System (INIS)

    Bengtsson, J.

    1988-01-01

    A tensor equation has been used to derive the equations of motion for the curvilinear coordinate system customary used for accelerators. A Hamiltonian formalism, expanded to third order in the canonical variables, describing the transverse motion in an acceleration has also been developed. Time-dependent perturbation theory has been applied and computerized using a computer algebra system. In particular, the perturbations due to magnetic sextupoles have been calculated to second power in the sextupole strength. The frequency spectra for the betatron motion close to a single resonance has been calculated by using time-independent perturbation theory. It has been shown that information about excited resonances and the type of driving field can be derived from the spectra. In particular, it is possible to obtain the amplitude and the phase of a given resonance. The results have been used to study the perturbations in the Low Energy Antiproton Ring, LEAR at CERN. (With 67 refs.) (author)

  6. Non-linear transverse dynamics for storage rings with applications to the low-energy antiproton ring (LEAR) at CERN

    International Nuclear Information System (INIS)

    Bengtsson, J.

    1988-01-01

    A tensor equation has been used to derive the equations of motion for the curvilinear coordinate system customarily used for particle accelerators. A Hamiltonian formalism, expanded to third order in the canonical variables, has also been developed to describe the transverse motion in an accelerator. Time-dependent perturbation theory has been applied and computerized using a computer-algebra system. In particular, the perturbations due to magnetic sextupoles have been calculated to second power in the sextupole strength. The frequency spectra for the horizontal and the vertical betatron motion close to a single resonance have been calculated using time-independent perturbation theory. It has been shown that information about excited resonances and the type of driving field can be derived from the spectra. In particular, it is possible to obtain the amplitude and the phase of a given resonance. The results have been used to study the perturbations in the Low Energy Antiproton Ring (LEAR) at CERN. (orig.)

  7. Adsorption and ring-opening of lactide on the chiral metal surface Pt(321){sup S} studied by density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Franke, J.-H.; Kosov, D. S. [Department of Physics, Campus Plaine - CP 231, Universite Libre de Bruxelles, 1050 Brussels (Belgium)

    2015-01-28

    We study the adsorption and ring-opening of lactide on the naturally chiral metal surface Pt(321){sup S}. Lactide is a precursor for polylactic acid ring-opening polymerization, and Pt is a well known catalyst surface. We study, here, the energetics of the ring-opening of lactide on a surface that has a high density of kink atoms. These sites are expected to be present on a realistic Pt surface and show enhanced catalytic activity. The use of a naturally chiral surface also enables us to study potential chiral selectivity effects of the reaction at the same time. Using density functional theory with a functional that includes the van der Waals forces in a first-principles manner, we find modest adsorption energies of around 1.4 eV for the pristine molecule and different ring-opened states. The energy barrier to be overcome in the ring-opening reaction is found to be very small at 0.32 eV and 0.30 eV for LL- and its chiral partner DD-lactide, respectively. These energies are much smaller than the activation energy for a dehydrogenation reaction of 0.78 eV. Our results thus indicate that (a) ring-opening reactions of lactide on Pt(321) can be expected already at very low temperatures, and Pt might be a very effective catalyst for this reaction; (b) the ring-opening reaction rate shows noticeable enantioselectivity.

  8. Positron--electron storage ring project: Stanford Linear Accelerator Center, Stanford, California. Final environmental statement

    International Nuclear Information System (INIS)

    1976-08-01

    A final environmental statement is given which was prepared in compliance with the National Environmental Policy Act to support the Energy Research and Development Administration project to design and construct the positron-electron colliding beam storage ring (PEP) facilities at the Stanford Linear Accelerator Center (SLAC). The PEP storage ring will be constructed underground adjacent to the existing two-mile long SLAC particle accelerator to utilize its beam. The ring will be about 700 meters in diameter, buried at depths of 20 to 100 feet, and located at the eastern extremity of the SLAC site. Positron and electron beams will collide in the storage ring to provide higher energies and hence higher particle velocities than have been heretofore achieved. Some of the energy from the collisions is transformed back into matter and produces a variety of particles of immense interest to physicists. The environmental impacts during the estimated two and one-half years construction period will consist of movement of an estimated 320,000 cubic yards of earth and the creation of some rubble, refuse, and dust and noise which will be kept to a practical minimum through planned construction procedures. The terrain will be restored to very nearly its original conditions. Normal operation of the storage ring facility will not produce significant adverse environmental effects different from operation of the existing facilities and the addition of one water cooling tower. No overall increase in SLAC staff is anticipated for operation of the facility. Alternatives to the proposed project that were considered include: termination, postponement, other locations and construction of a conventional high energy accelerator

  9. The Ring Counter (RCo): A high resolution IC-Si-CsI(Tl) device for heavy ion reaction studies at 10-30 MeV/A

    International Nuclear Information System (INIS)

    Moroni, A.; Bruno, M.; Bardelli, L.; Barlini, S.; Brambilla, S.; Casini, G.; Cavaletti, R.; Chiari, M.; Cortesi, A.; D'Agostino, M.; De Sanctis, J.; Geraci, E.; Giordano, G.; Giussani, A.; Gramegna, F.; Guiot, B.; Kravchuk, V.; Lanchais, A.; Margagliotti, G.V.; Nannini, A.; Ordine, A.; Piantelli, S.; Vannini, G.; Vannucci, L.

    2006-01-01

    An annular detector (Ring Counter, RCo) is presented, which has been designed and built to detect and identify in mass and charge light charged particles and fragments with very low energy thresholds and high energy resolution. It complements the GARFIELD apparatus, operating at INFN Laboratori Nazionali di Legnaro, to detect the forward emitted products of nuclear heavy ion reactions. It consists of eight sectors of a three-stage telescope, each one formed by an ionization chamber followed by eight strips of a silicon detector and by two CsI(Tl) scintillators. Construction features and performances are described and discussed in details

  10. Storage ring at HIE-ISOLDE Technical design report

    NARCIS (Netherlands)

    Grieser, M.; Litvinov, Yu. A.; Raabe, R.; Blaum, K.; Blumenfeld, Y.; Butler, P. A.; Wenander, F.; Woods, P. J.; Aliotta, M.; Andreyev, A.; Artemyev, A.; Atanasov, D.; Aumann, T.; Balabanski, D.; Barzakh, A.; Batist, L.; Bernardes, A. -P.; Bernhardt, D.; Billowes, J.; Bishop, S.; Borge, M.; Borzov, I.; Boston, A. J.; Brandau, C.; Catford, W.; Catherall, R.; Cederkall, J.; Cullen, D.; Davinson, T.; Dillmann, I.; Dimopoulou, C.; Dracoulis, G.; Duellmann, Ch. E.; Egelhof, P.; Estrade, A.; Fischer, D.; Flanagan, K.; Fraile, L.; Fraser, M. A.; Freeman, S. J.; Geissel, H.; Gerl, J.; Greenlees, P.; Grisenti, R. E.; Habs, D.; von Hahn, R.; Hagmann, S.; Hausmann, M.; He, J. J.; Heil, M.; Huyse, M.; Jenkins, D.; Jokinen, A.; Jonson, B.; Joss, D. T.; Kadi, Y.; Kalantar-Nayestanaki, N.; Kay, B. P.; Kiselev, O.; Kluge, H. -J.; Kowalska, M.; Kozhuharov, C.; Kreim, S.; Kroell, T.; Kurcewicz, J.; Labiche, M.; Lemmon, R. C.; Lestinsky, M.; Lotay, G.; Ma, X. W.; Marta, M.; Meng, J.; Muecher, D.; Mukha, I.; Mueller, A.; Murphy, A. St J.; Neyens, G.; Nilsson, T.; Nociforo, C.; Noertershaeuser, W.; Page, R. D.; Pasini, M.; Petridis, N.; Pietralla, N.; Pfuetzner, M.; Podolyak, Z.; Regan, P.; Reed, M. W.; Reifarth, R.; Reiter, P.; Repnow, R.; Riisager, K.; Rubio, B.; Sanjari, M. S.; Savin, D. W.; Scheidenberger, C.; Schippers, S.; Schneider, D.; Schuch, R.; Schwalm, D.; Schweikhard, L.; Shubina, D.; Siesling, E.; Simon, H.; Simpson, J.; Smith, J.; Sonnabend, K.; Steck, M.; Stora, T.; Stoehlker, T.; Sun, B.; Surzhykov, A.; Suzaki, F.; Tarasov, O.; Trotsenko, S.; Tu, X. L.; Van Duppen, P.; Volpe, C.; Voulot, D.; Walker, P. M.; Wildner, E.; Winckler, N.; Winters, D. F. A.; Wolf, A.; Xu, H. S.; Yakushev, A.; Yamaguchi, T.; Yuan, Y. J.; Zhang, Y. H.; Zuber, K.; Bosch, F.M.

    We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams

  11. Ring Theory

    CERN Document Server

    Jara, Pascual; Torrecillas, Blas

    1988-01-01

    The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.

  12. Spin transitions in semiconductor quantum rings

    International Nuclear Information System (INIS)

    Baxevanis, Benjamin; Pfannkuche, Daniela

    2010-01-01

    We adopt the path integral Monte Carlo method to accurately resolve the total spin of the ground state of electrons confined in a quantum ring with different geometries. Using this method, an evaluation of the ground state of three electrons in a ring shows a spin transition to the fully polarized state by increasing the radius and thereby enhancing the Coulomb interaction. The total spin of the ground state is determined by the mutual interplay of confinement and electron-electron interaction. An analysis of the four-electron ring demonstrates that in this case no spin transitions take place. Furthermore, the effect of geometric distortion of the ring on its ground state has been investigated. Elliptically deforming the ring breaks the symmetry of the system and leads to the removal of orbital degeneracy. For strong distortion the splitting between hybridized states is sufficient to overcome the exchange-energy saving associated with a higher spin state. We have found that this effect removes the polarization of three electrons. Even in a four-electron ring the ground state is forced by the distortion to be unpolarized and thus suppressing the Hund's rule ground state.

  13. INJECTION EFFICIENCY IN COMPTON RING NESTOR

    Directory of Open Access Journals (Sweden)

    P. I. Gladkikh

    2017-12-01

    Full Text Available NESTOR is the hard X-ray source that is under commissioning at NSC KIPT. NESTOR based on the Compton scattering of laser photons on relativistic electrons. The structure of the facility can be represented as the following components: a linear accelerator, a transport channel, a storage ring, and a laser-optical system. Electrons are stored in the storage ring for energy of 40-200 MeV. Inevitable alignment errors of magnetic elements are strongly effect on the beam dynamics in the storage ring. These errors lead to a shift of the equilibrium orbit relative to the ideal one. Significant shift of the equilibrium orbit could lead to loss of the beam on physical apertures. Transverse sizes of electron and laser beams are only few tens of microns at the interaction point. The shift of electron beam at the interaction point could greatly complicate the operation adjustment of storage ring without sufficient beam position diagnostic system. This article presents the simulation results of the efficiency of electron beam accumulation in the NESTOR storage ring. Also, this article is devoted to electron beam dynamics due to alignment errors of magnetic element in the ring.

  14. Active interlock system for high power insertion devices in the x-ray ring

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    In modern synchrotron radiation rings photon beams generated by high power insertion devices (IDs) may be sufficiently intense to cause severe thermal damage to the machine vacuum chamber if mis-steered. Thus when operating a storage ring with the IDs, great care must be exercised to prevent mis-steering of the electron beam orbit. At present, the X-ray ring operates with three IDs, namely two hybrid wigglers (HBW) at X-21 and X-25,a nd a 5-Tesla superconducting wiggler at X-17. All wigglers are located in low-beta straight sections. In the straight sections. In the straight sections, beam orbit may be deflected by as much as ±8 mrad without scraping the chamber wall. For various reasons it was not possible to design the X-ray ring vacuum chamber to be safe under all possible operating conditions, however, the chamber is safe for i < 7 mA, all horizontal beam deflection angles and for vertical angles < ± 2.5 mrad. To protect the machine vacuum chamber from damage due to mis-steered beams, and interlock system has been developed and installed. This system utilizes active beam position detectors which continuously monitor beam motion in each of the ID straight sections and logic circuitry which interrupts the RF and dumps the stored beam in the case of a fault

  15. Beam Aborts in PEP-II Rings and Lingering Drift Chamber Currents

    International Nuclear Information System (INIS)

    Meshkat, N.

    2004-01-01

    The BABAR detector at SLAC was designed to study CP-violation in B-meson decays from electron-positron collisions in the PEP-II electron-positron storage rings. Background radiation in the High Energy Ring (HER) and Low Energy Ring (LER) of PEP-II has the potential to damage the sensitive equipment in the BABAR detector. As a result, the beams in the HER and LER can be aborted to prevent such damage. In the span of a few microseconds, the HER and LER currents drop from, for example, 1450 micro Amps and 2300 micro Amps, respectively, to zero. At this time the voltage in the Drift Chamber is rapidly ramped down from a potential of 1930 V to a safe potential of 800 V, thus we would expect the currents in the Drift Chamber to quickly go to zero once the beams are aborted. However, we observe an average 15 second delay in the measured time it takes for all current in the Drift Chamber to fall below 1 micro Amp. This delay has been hypothesized as an instrumentation issue and not as a physical phenomenon. The specific sources of this error are still not completely known, but analysis suggests that it results from the interplay of the CAEN High Voltage supplies and the EPICS system and/or limitations within those systems

  16. Can Baird's and Clar's Rules Combined Explain Triplet State Energies of Polycyclic Conjugated Hydrocarbons with Fused 4nπ- and (4n + 2)π-Rings?

    Science.gov (United States)

    Ayub, Rabia; Bakouri, Ouissam El; Jorner, Kjell; Solà, Miquel; Ottosson, Henrik

    2017-06-16

    Compounds that can be labeled as "aromatic chameleons" are π-conjugated compounds that are able to adjust their π-electron distributions so as to comply with the different rules of aromaticity in different electronic states. We used quantum chemical calculations to explore how the fusion of benzene rings onto aromatic chameleonic units represented by biphenylene, dibenzocyclooctatetraene, and dibenzo[a,e]pentalene modifies the first triplet excited states (T 1 ) of the compounds. Decreases in T 1 energies are observed when going from isomers with linear connectivity of the fused benzene rings to those with cis- or trans-bent connectivities. The T 1 energies decreased down to those of the parent (isolated) 4nπ-electron units. Simultaneously, we observe an increased influence of triplet state aromaticity of the central 4n ring as given by Baird's rule and evidenced by geometric, magnetic, and electron density based aromaticity indices (HOMA, NICS-XY, ACID, and FLU). Because of an influence of triplet state aromaticity in the central 4nπ-electron units, the most stabilized compounds retain the triplet excitation in Baird π-quartets or octets, enabling the outer benzene rings to adapt closed-shell singlet Clar π-sextet character. Interestingly, the T 1 energies go down as the total number of aromatic cycles within a molecule in the T 1 state increases.

  17. Prospects of high-resolution resonant X-ray inelastic scattering studies on solid materials, liquids and gases at diffraction-limited storage rings

    International Nuclear Information System (INIS)

    Schmitt, Thorsten; Groot, Frank M. F. de; Rubensson, Jan-Erik

    2014-01-01

    Diffraction-limited storage rings will allow for pushing the achievable energy resolution, signal intensity and the sampled spot size in resonant inelastic X-ray scattering (RIXS) experiments to new limits. In this article the types of improved soft X-ray RIXS studies that will become possible with these instrumental improvements are envisioned. The spectroscopic technique of resonant inelastic X-ray scattering (RIXS) will particularly profit from immensely improved brilliance of diffraction-limited storage rings (DLSRs). In RIXS one measures the intensities of excitations as a function of energy and momentum transfer. DLSRs will allow for pushing the achievable energy resolution, signal intensity and the sampled spot size to new limits. With RIXS one nowadays probes a broad range of electronic systems reaching from simple molecules to complex materials displaying phenomena like peculiar magnetism, two-dimensional electron gases, superconductivity, photovoltaic energy conversion and heterogeneous catalysis. In this article the types of improved RIXS studies that will become possible with X-ray beams from DLSRs are envisioned

  18. An experimental study on the long-term stability of particle motion in hadron storage rings

    International Nuclear Information System (INIS)

    Fischer, W.

    1995-12-01

    Nonlinear magnetic fields in conjunction with tune modulation may lead to chaotic particle motion and thereby limit the dynamic aperture in hadron storage rings. This is on particular interest for high energy storage rings with superconducting magnets at injection energy where magnetic field errors and the beam size have their maximum values. At the CERN SPS a dynamic aperture experiment was performed with the aim of finding the relevant effects for the stability of single particle motion in hadron storage rings. Experimental results are compared to long-term particle tracking to test to which extent computer programs can predict the dynamic aperture under well known conditions. In addition, detailed investigations of the loss mechanisms were pursued to improve the phenomenological understanding of the intricate details of particle motion in phase space. In a complementary experiment at the HERA proton ring at injection energy the dynamic aperture was measured under normal operating conditions. The computer simulations for these measurements included a very detailed model of the nonlinear fields which were measured for each individual magnet. Simulation results for the LHC are shown that estimate the effect of tune ripple of different strength on the dynamic aperture for different sets of random nonlinear field errors. (orig.)

  19. The Cryogenic Storage Ring CSR

    OpenAIRE

    von Hahn, Robert; Becker, Arno; Berg, Felix; Blaum, Klaus; Breitenfeldt, Christian; Fadil, Hisham; Fellenberger, Florian; Froese, Michael; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth A.; Heber, Oded; Herwig, Philipp

    2016-01-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion a...

  20. Examination techniques for non-magnetic rings

    International Nuclear Information System (INIS)

    Metala, M.J.; Kilpatrick, N.L.; Frank, W.W.

    1990-01-01

    Until the introduction of 18Mn18Cr rings a few years ago, most non-magnetic steel rings for generator rotors were made from 18Mn5Cr alloy steel, which is highly susceptible to stress corrosion cracking in the presence of water. This, the latest in a series of papers on the subject of non-magnetic rings by the authors' company, provides a discussion of nondestructive examination of 18Mn5Cr rings for stress corrosion distress. With rings on the rotor, fluorescent penetrant, ultrasonic and special visual techniques are applied. With rings off the rotor, the fluorescent penetrant technique is used, with and without stress enhancement

  1. Compact electron storage rings

    International Nuclear Information System (INIS)

    Williams, G.P.

    1987-01-01

    There have been many recent developments in the area of compact storage rings. Such rings would have critical wavelengths of typically 10 A, achieved with beam energies of several hundreds of MeV and superconducting dipole fields of around 5 Tesla. Although the primary motivation for progress in this area is that of commercial x-ray lithography, such sources might be an attractive source for college campuses to operate. They would be useful for many programs in materials science, solid state, x-ray microscopy and other biological areas. We discuss the properties of such sources and review developments around the world, primarily in the USA, japan and W. Germany

  2. Compact high-efficiency vortex beam emitter based on a silicon photonics micro-ring

    DEFF Research Database (Denmark)

    Li, Shimao; Ding, Yunhong; Guan, Xiaowei

    2018-01-01

    Photonic integrated devices that emit vortex beam carrying orbital angular momentum are becoming key components for multiple applications. Here we propose and demonstrate a high-efficiency vortex beam emitter based on a silicon micro-ring resonator integrated with a metal mirror. Such a compact...

  3. Electron density enhancement in a quasi isochronous storage ring

    International Nuclear Information System (INIS)

    Pellegrini, C.; Robin, D.

    1991-01-01

    The six dimensional phase-space density of an electron beam in a storage ring is determined by the emission of synchrotron radiation, and by the transverse and longitudinal focusing forces determining the particle trajectories. In the simplest case of uncoupled horizontal, vertical and longitudinal motion, the phase space volume occupied by the beam can be characterized by the product of its three projections on the single degree of freedom planes, the horizontal, vertical, and longitudinal emittances. To minimize the beam phase space volume the authors can minimize the transverse and longitudinal emittances. In the case of transverse emittances this problem is very important for synchrotron radiation sources, and has been studied by several authors. A method to minimize the longitudinal emittance, and produce electron bunches with a short pulse length, small energy spread and large peak current has been proposed and discussed recently by C. Pellegrini and D. Robin. This method uses a ring in which the revolution period is weakly dependent on the particle energy, Quasi Isochronous Ring (QIR), in other words a ring with a momentum compaction nearly zero. In this paper they will extend the previous analysis of the conditions for stable single particle motion in such a ring, and give simple criteria for the estimate of the energy spread and phase acceptance of a QIR

  4. How Many Muons Do We Need to Store in a Ring For Neutrino Cross-Section Measurements?

    International Nuclear Information System (INIS)

    Geer, Steve

    2011-01-01

    Analytical estimate of the number of muons that must decay in the straight section of a storage ring to produce a neutrino and anti-neutrino beam of sufficient intensity to facilitate cross-section measurements with a statistical precision of 1%. As we move into the era of precision long-baseline ν μ → ν e and (bar ν) μ → (bar ν) e measurements there is a growing need to precisely determine the ν e and (bar ν) e cross-sections in the relevant energy range, from a fraction of 1 GeV to a few GeV. This will require ν e and (bar ν) e beams with precisely known fluxes and spectra. One way to produce these beams is to use a storage ring with long straight sections in which muon decays (μ - → e - ν μ (bar ν) e if negative muons are stored, and ν + → e + ν e (bar ν) μ if positive muons are stored) produce the desired beam. The challenge is to capture enough muons in the ring to obtain useful neutrino and anti-neutrino fluxes. Early proposals to use a muon storage ring for neutrino oscillation experiments were based upon injecting 'high energy' charged pions into the ring which then decayed to create stored muons. These proposals were hampered by lack of sufficient intensity to pursue the physics. The Neutrino Factory proposal in 1997 was designed to fix this problem by using a Muon Collider class 'low energy' muon source to capture many more pions at low energy, allow them to decay in an external decay channel, manipulate their phase space to capture as many muons as possible within the acceptance of an accelerator, and then accelerate to the energy of choice before injecting into a specially designed ring with long straight sections. All this technology would do a wonderful job in fixing the intensity problem, but at a price that excludes this solution from being realized in the short term. The question that we are now faced with is whether the older, lower intensity 'parasitic' muon storage ring based on 'high energy' pion decays can, with

  5. Conceptual design of a moving-ring reactor

    International Nuclear Information System (INIS)

    Smith, A.C.; Carlson, G.A.; Ashworth, C.P.

    1986-01-01

    A design of a prototype moving-ring reactor was completed, and a development plan for a pilot reactor is outlined. The fusion fuel is confined in current-carrying rings of magnetically field-reversed plasma (''compact toroids''). The plasma rings, formed by a coaxial plasma gun, undergo adiabatic magnetic compression to ignition temperature while they are being injected into the reactor's burner section. The cylindrical burner chamber is divided into three ''burn stations.'' Separator coils and a slight axial guide field gradient are used to shuttle the ignited toroids rapidly from one burn station to the next, pausing for one-third of the total burn time at each station. Deuterium-tritium- 3 He ice pellets refuel the rings at a rate that maintains constant radiated power. The fusion power per ring is approx. =105.5 MW. The burn time to reach a fusion energy gain of Q = 30 is 5.9 s

  6. Injection into the LNLS UVX electron storage ring

    International Nuclear Information System (INIS)

    Lin, Liu

    1991-01-01

    To inject the 1.15 GeV electron storage ring - UVX - a beam from a linear accelerator - MAIRA - is used. The electrons are injected and accumulated at low energy (100MeV) until the nominal current of 100 mA is reached and than are ramped to the nominal energy. A study on a conventional injection scheme has been carried out. Two injection modes are investigated: injection with the phase ellipse parameters matched and mismatched to the ring's acceptance. The mismatched mode is optimized to fit the maximum of the injected beam into the acceptance

  7. Survey and alignment of the Fermilab recycler antiproton storage ring

    International Nuclear Information System (INIS)

    Arics, Babatunde O.O.

    1999-01-01

    In June of 1999 Fermilab commissioned a newly constructed antiproton storage ring, the 'Recycler Ring', in the Main Injector tunnel directly above the Main Injector beamline. The Recycler Ring is a fixed 8 GeV kinetic energy storage ring and is constructed of strontium ferrite permanent magnets. The 3319.4-meter-circumference Recycler Ring consists of 344 gradient magnets and 100 quadrupoles all of which are permanent magnets. This paper discusses the methods employed to survey and align these permanent magnets within the Recycler Ring with the specified accuracy. The Laser Tracker was the major instrument used for the final magnet alignment. The magnets were aligned along the Recycler Ring with a relative accuracy of ±0.25 mm. (author)

  8. The RING 2.0 web server for high quality residue interaction networks.

    Science.gov (United States)

    Piovesan, Damiano; Minervini, Giovanni; Tosatto, Silvio C E

    2016-07-08

    Residue interaction networks (RINs) are an alternative way of representing protein structures where nodes are residues and arcs physico-chemical interactions. RINs have been extensively and successfully used for analysing mutation effects, protein folding, domain-domain communication and catalytic activity. Here we present RING 2.0, a new version of the RING software for the identification of covalent and non-covalent bonds in protein structures, including π-π stacking and π-cation interactions. RING 2.0 is extremely fast and generates both intra and inter-chain interactions including solvent and ligand atoms. The generated networks are very accurate and reliable thanks to a complex empirical re-parameterization of distance thresholds performed on the entire Protein Data Bank. By default, RING output is generated with optimal parameters but the web server provides an exhaustive interface to customize the calculation. The network can be visualized directly in the browser or in Cytoscape. Alternatively, the RING-Viz script for Pymol allows visualizing the interactions at atomic level in the structure. The web server and RING-Viz, together with an extensive help and tutorial, are available from URL: http://protein.bio.unipd.it/ring. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  9. Optimizing ring-based CSR sources

    International Nuclear Information System (INIS)

    Byrd, J.M.; De Santis, S.; Hao, Z.; Martin, M.C.; Munson, D.V.; Li, D.; Nishimura, H.; Robin, D.S.; Sannibale, F.; Schlueter, R.D.; Schoenlein, R.; Jung, J.Y.; Venturini, M.; Wan, W.; Zholents, A.A.; Zolotorev, M.

    2004-01-01

    Coherent synchrotron radiation (CSR) is a fascinating phenomenon recently observed in electron storage rings and shows tremendous promise as a high power source of radiation at terahertz frequencies. However, because of the properties of the radiation and the electron beams needed to produce it, there are a number of interesting features of the storage ring that can be optimized for CSR. Furthermore, CSR has been observed in three distinct forms: as steady pulses from short bunches, bursts from growth of spontaneous modulations in high current bunches, and from micro modulations imposed on a bunch from laser slicing. These processes have their relative merits as sources and can be improved via the ring design. The terahertz (THz) and sub-THz region of the electromagnetic spectrum lies between the infrared and the microwave . This boundary region is beyond the normal reach of optical and electronic measurement techniques and sources associated with these better-known neighbors. Recent research has demonstrated a relatively high power source of THz radiation from electron storage rings: coherent synchrotron radiation (CSR). Besides offering high power, CSR enables broadband optical techniques to be extended to nearly the microwave region, and has inherently sub-picosecond pulses. As a result, new opportunities for scientific research and applications are enabled across a diverse array of disciplines: condensed matter physics, medicine, manufacturing, and space and defense industries. CSR will have a strong impact on THz imaging, spectroscopy, femtosecond dynamics, and driving novel non-linear processes. CSR is emitted by bunches of accelerated charged particles when the bunch length is shorter than the wavelength being emitted. When this criterion is met, all the particles emit in phase, and a single-cycle electromagnetic pulse results with an intensity proportional to the square of the number of particles in the bunch. It is this quadratic dependence that can

  10. A ring image Cerenkov detector for the CERN Omega Spectrometer

    International Nuclear Information System (INIS)

    Davenport, M.; Deol, R.S.; Flower, P.S.

    1983-05-01

    A development program has been undertaken to produce a large ring image Cerenkov detector (RICH) for use at the CERN Omega Spectrometer. A prototype Cerenkov counter has been constructed and successfully operated in a high energy particle beam, Cerenkov rings having been observed in an experimental time projection chamber (TPC) using the photoionising agents Triethylamine (TEA) and Tetrakis (dimethylamine) ethylene (TMAE). Systematic measurements have been made of the optical properties of window materials and reflecting surfaces in the vacuum ultraviolet region. Results of these tests are presented, and the design of the large detector based on these experiences together with Monte Carlo simulations of the events expected in the WA69 experiment, is discussed. (author)

  11. High energy experimental physics. Progress report and renewal proposal

    International Nuclear Information System (INIS)

    Rosen, J.; Miller, D.

    1985-01-01

    Technical progress is summarized for activities in these areas: study of charm particle production in hadronic collisions (data analysis); large-aperture multiparticle spectrometer; TEV I debuncher ring profile monitor; beta source monochromatizer; final reduction of data from pp and p anti p elastic scattering; high energy elastic scattering and cross section review; consequences of the Auberson-Kinoshita-Martin theorem for the nuclear slope parameter; planning and final design of the elastic scattering and total cross section experiment at the Tevatron Collider; a D-zero pp project and photoproduction experiment; lepton production in heavy-ion collisions; prompt gamma and massive lepton-pair production apparatus; and spin physics with the Fermilab polarized beam facility

  12. Full Dynamic Ball Bearing Model with Elastic Outer Ring for High Speed Applications

    Directory of Open Access Journals (Sweden)

    Christian Wagner

    2017-06-01

    Full Text Available Ball bearings are commonly used in high speed turbomachinery and have a critical influence on the rotordynamic behavior. Therefore, a simulation model of the bearing to predict the dynamic influence is essential. The presented model is a further step to develop an accurate and efficient characterization of the ball bearing’s rotor dynamic parameters such as stiffness and deflections as well as vibrational excitations induced by the discrete rolling elements. To make it applicable to high speed turbomachinery, the model considers centrifugal forces, gyroscopic effects and ball spinning. The consideration of an elastic outer ring makes the bearing model suitable for integrated lightweight bearing constructions used in modern aircraft turbines. In order to include transient rotordynamic behavior, the model is built as a full dynamic multibody simulation with time integration. To investigate the influence of the elasticity of the outer ring, a comparison with a rigid formulation for several rotational speeds and loads is presented.

  13. Fano resonance and persistent current of a quantum ring

    International Nuclear Information System (INIS)

    Xiong Yongjian; Liang Xianting

    2004-01-01

    We investigate electron transport and persistent current of a quantum ring weakly attached to current leads. Assuming there is direct coupling (weakly or strongly) between two leads, electrons can transmit by the inter-lead coupling or tunneling through the quantum ring. The interference between the two paths yields asymmetric Fano line shape for conductance. In presence of interior magnetic flux, there is persistent current along the ring with narrow resonance peaks. The positions of the conductance resonances and the persistent current peaks correspond to the quasibound levels of the closed ring. This feature is helpful to determine the energy spectrum of the quantum ring. Our results show that the proposed setup provides a tunable Fano system

  14. The dynamics of rings around small, irregular bodies

    Science.gov (United States)

    Sicardy, Bruno

    2017-06-01

    Stellar occultations revealed the presence of two dense rings around the Centaur object (10199) Chariklo (Braga-Ribas et al., Nature 508, 72, 2014). This is the first ring system discovered around an object that is not a giant planet, suggesting that rings may exist around numerous bodies in the solar system. Chariklo's rings roughly reside at the outer limit of the Roche zone of the body. Moreover, the main ring has sharp edges, which call for the presence of putative shepherd satellites. Those characteristics give an image of Chariklo's rings that are rather similar, in terms of dynamics, to those surrounding the gaseous planets.An important difference exists, however, between giant planets and small bodies: the formers are highly axisymmetric, while the latters can support mass anomalies (eg surface topographic features) or non-spherical shapes (eg an ellipsoidal figure of equilibrium) that involve masses, relative to the body itself, as large as 10-4-10-3.We investigate the effect of non-axisymmetric terms in the potential of the body upon a collisional debris disk that initially surrounds a small irregular body. We show that the corotation points being maxima of energy, dissipative collisions remove the particles from the corotation zone over short time scales (< 106 years). Moreover, the Lindblad resonances inside the corotation radius create torques that drive the particles onto the surface of the central body. Conversely, the outer Lindblad resonances push the disk material beyond the outer 3/2 and 2/1 Lindblad resonances.Taking as an example Chariklo's ring system, for which recent data have been obtained from stellar occultations, we show that the Lindblad resonant torques actuate over short time scales (< 106 years). This general picture offers a natural explanation of the presence of dense rings at the outer limit of Chariklo's Roche zone, and their absence closer to the body.The work leading to this results has received funding from the European

  15. Effects of decaying image currents on electron rings during compression between side walls and motion along conducting cylinders

    International Nuclear Information System (INIS)

    Herrmann, W.

    1974-11-01

    Decaying image currents consume energy which has to be supplied by the field producing electron ring. For very high currents (I > 10 3 A, particle number Ne > approximately 10 14 ) the losses become important and have to be included in the calculation of the ring dynamics. Special attention has been given to the focussing effects of the decaying image currents during compression and to the retarding force which develops when the ring is moved along a resistive cylinder. It is emphasized that in the latter case the ring experiences a 'run-away-situation', when the ratio of its velocity to the surface resistivity exceeds a certain limit. (orig.) [de

  16. Electron localization and optical absorption of polygonal quantum rings

    Science.gov (United States)

    Sitek, Anna; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

    2015-06-01

    We investigate theoretically polygonal quantum rings and focus mostly on the triangular geometry where the corner effects are maximal. Such rings can be seen as short core-shell nanowires, a generation of semiconductor heterostructures with multiple applications. We show how the geometry of the sample determines the electronic energy spectrum, and also the localization of electrons, with effects on the optical absorption. In particular, we show that irrespective of the ring shape low-energy electrons are always attracted by corners and are localized in their vicinity. The absorption spectrum in the presence of a magnetic field shows only two peaks within the corner-localized state domain, each associated with different circular polarization. This picture may be changed by an external electric field which allows previously forbidden transitions, and thus enables the number of corners to be determined. We show that polygonal quantum rings allow absorption of waves from distant ranges of the electromagnetic spectrum within one sample.

  17. Development of a Bunched Beam Electron Cooler based on ERL and Circulator Ring Technology for the Jefferson Lab Electron-Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Stephen V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Derbenev, Yaroslav S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hannon, Fay E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hutton, Andrew M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Rimmer, Robert A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Roblin, Yves R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wang, Haipeng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, He [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, Yuhong [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2018-01-01

    Jefferson Lab is in the process of designing an electron ion collider with unprecedented luminosity at a 45 GeV center-of-mass energy. This luminosity relies on ion cooling in both the booster and the storage ring of the accelerator complex. The cooling in the booster will use a conventional DC cooler similar to the one at COSY. The high-energy storage ring, operating at a momentum of up to 100 GeV/nucleon, requires novel use of bunched-beam cooling. There are two designs for such a cooler. The first uses a conventional Energy Recovery Linac (ERL) with a magnetized beam while the second uses a circulating ring to enhance both peak and average currents experienced by the ion beam. This presentation will describe the design of both the Circulator Cooling Ring (CCR) design and that of the backup option using the stand-alone ERL operated at lower charge but higher repetition rate than the ERL injector required by the CCR-based design.

  18. Two superconducting storage rings: ISABELLE

    International Nuclear Information System (INIS)

    Sanford, J.R.

    1978-01-01

    The general features of the design and the status of the ISABELLE storage ring project at the present time are reported. It brings up to date the results reported at the National Particle Accelerator Conference in March 1977. The most significant change since that time has been an upgrading of the energy of the overall facility, and acceptance of the project by the Department of Energy

  19. Coulomb collisions of ring current particles: Indirect source of heat for the ionosphere

    Science.gov (United States)

    Cole, K. D.

    1975-01-01

    The additional energy requirements of the topside ionosphere during a magnetic storm are less than one quarter of the ring current energy. This energy is supplied largely by Coulomb collisions of ring current protons of energy less than about 20 keV with background thermal electrons which conduct the heat to the ionosphere. Past criticisms are discussed of this mechanism for the supply of energy to the SAR-arc and neighboring regions of the ionosphere.

  20. The Mechanics of a Chain or Ring of Spherical Magnets

    KAUST Repository

    Hall, Cameron L.; Vella, Dominic; Goriely, Alain

    2013-01-01

    Strong magnets, such as neodymium-iron-boron magnets, are increasingly being manufactured as spheres. Because of their dipolar characters, these spheres can easily be arranged into long chains that exhibit mechanical properties reminiscent of elastic strings or rods. While simple formulations exist for the energy of a deformed elastic rod, it is not clear whether or not they are also appropriate for a chain of spherical magnets. In this paper, we use discrete-to-continuum asymptotic analysis to derive a continuum model for the energy of a deformed chain of magnets based on the magnetostatic interactions between individual spheres. We find that the mechanical properties of a chain of magnets differ significantly from those of an elastic rod: while both magnetic chains and elastic rods support bending by change of local curvature, nonlocal interaction terms also appear in the energy formulation for a magnetic chain. This continuum model for the energy of a chain of magnets is used to analyze small deformations of a circular ring of magnets and hence obtain theoretical predictions for the vibrational modes of a circular ring of magnets. Surprisingly, despite the contribution of nonlocal energy terms, we find that the vibrations of a circular ring of magnets are governed by the same equation that governs the vibrations of a circular elastic ring. Copyright © by SIAM.

  1. Electric dipole moment of magnetoexciton in concentric quantum rings

    Science.gov (United States)

    García, L. F.; Mikhailov, I. D.; Revinova, S. Yu

    2017-12-01

    We study properties of exciton in a weakly coupled concentric quantum rings, penetrated by an axially directed magnetic flux and subjected to an electric field in the ring’s plane. To this end, we adopt a simple model of quasi-one-dimensional rotator, for which the wave functions and the corresponding energies we found by using the double Fourier series expansion method. Revealed multiple intersections of the energy levels provide conditions for abrupt changes of the radial and the angular quantum numbers, making possible the tunnelling of carriers between rings and allowing the formation of a permanent large dipole moment. We show that the electric and magnetic polarizability of concentric quantum rings with a trapped exciton are very sensible to external electric and magnetic fields.

  2. 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.

  3. Evolution of the ring current during two geomagnetic storms

    International Nuclear Information System (INIS)

    Lui, A.T.Y.; McEntire, R.W.; Krimigis, S.M.

    1987-01-01

    The progressive developments in the radial profiles of the particle pressure, plasma beta, and electric currents of the storm time ring current are investigated with data from the medium energy particle analyzer on the AMPTE Charged Particle Explorer spacecraft. Measurements of ions from 25 keV to 1 MeV, which carry 70--85% of the energy density of the entire ring current population, are used in this work. Two geomagnetic storms in September of 1984 are selected and four traversals of the equatorial ring current region during the course of each storm are studied. It is shown that enhancements in the particle pressure occur initially in the outer region and reach the inner region in the late phase of the storm. Structures suggestive of multiple particle injections are seen in the pressure profile. The leading and trailing edges of the particle injection structures are associated, respectively, with the depressions and enhancements of the westward current densities of the ring current. Plasma beta occasionally increases to values of the order of 1 in some regions of the ring current from prestorm values of the order of 0.1 or less. It is also found that the location of the maximum ring current particle pressure can be several earth radii from where the most intense westward ring current flows. This is a consequence of the dominance of pressure gradient current over the current associated with the magnetic field line curvature and particle anisotropy. copyright American Geophysical Union 1987

  4. Specific heat in diluted magnetic semiconductor quantum ring

    Science.gov (United States)

    Babanlı, A. M.; Ibragimov, B. G.

    2017-11-01

    In the present paper, we have calculated the specific heat and magnetization of a quantum ring of a diluted magnetic semiconductor (DMS) material in the presence of magnetic field. We take into account the effect of Rashba spin-orbital interaction, the exchange interaction and the Zeeman term on the specific heat. We have calculated the energy spectrum of the electrons in diluted magnetic semiconductor quantum ring. Moreover we have calculated the specific heat dependency on the magnetic field and Mn concentration at finite temperature of a diluted magnetic semiconductor quantum ring.

  5. Proton ring trapping in a gated magnetic mirror

    International Nuclear Information System (INIS)

    Pedrow, P.D.; Greenly, J.B.; Hammer, D.A.; Sudan, R.N.

    1985-01-01

    An axis-encircling proton ring has been trapped for times (roughly-equal4 μs) much longer than the ion cyclotron period (roughly-equal80 ns). The rings, with mean radius 10 cm and with particle energies 15 protons during the first pass and 2 x 10 13 protons during the eighth and final pass. With a central solenoidal field of 0.8 T, the peak diamagnetism and azimuthal current density of the injected ring were typically 10 mT (100 G) and 10 A/cm 2 , respectively

  6. Ring recognition and electron identification in the RICH detector of the CBM experiment at FAIR

    International Nuclear Information System (INIS)

    Lebedev, S; Hoehne, C; Ososkov, G

    2010-01-01

    The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility at Darmstadt will measure dileptons emitted from the hot and dense phase in heavy-ion collisions. In case of an electron measurement, a high purity of identified electrons is required in order to suppress the background. Electron identification in CBM will be performed by a Ring Imaging Cherenkov (RICH) detector and Transition Radiation Detectors (TRD). In this contribution we will present algorithms and software which have been developed for electron identification in CBM. Efficient and fast ring recognition in the RICH detector is based on the Hough Transform method which has been accelerated considerably compared to a standard implementation. Ring quality selection is done using an Artificial Neural Network which also has been used for electron identification. Due to optical distortions ellipse fitting and radius corre ction routines are used for improved ring radius resolution. These methods allow for a high purity and efficiency of reconstructed electron rings. For momenta above 2 GeV/c the ring reconstruction efficiency for electrons embedded in central Au+Au collisions at 25 AGeV beam energy is 95% resulting in an electron identification efficiency of 90% at a pion suppression factor of 500. Including information from the TRD a pion suppression of 10 4 is reached at 80% efficiency. The developed algorithm is very robust to a high ring density environment. Current work focusses on detector layout studies in order to optimize the detector setup while keeping a high performance. All developed algorithms were tested on large statistics of simulated events and are included into the CBM software framework for common use.

  7. Electro-optical hybrid slip ring

    Science.gov (United States)

    Hong, En

    2005-11-01

    The slip ring is a rotary electrical interface, collector, swivel or rotary joint. It is a physical system that can perform continuous data transfer and data exchange between a stationary and a rotating structure. A slip ring is generally used to transfer data or power from an unrestrained, continuously rotating electro-mechanical system in real-time, thereby simplifying operations and eliminating damage-prone wires dangling from moving joints. Slip rings are widely used for testing, evaluating, developing and improving various technical equipment and facilities with rotating parts. They are widely used in industry, especially in manufacturing industries employing turbo machinery, as in aviation, shipbuilding, aerospace, defense, and in precise facilities having rotating parts such as medical Computerized Tomography (CT) and MRI scanners and so forth. Therefore, any improvement in slip ring technology can impact large markets. Research and development in this field will have broad prospects long into the future. The goal in developing the current slip ring technology is to improve and increase the reliability, stability, anti-interference, and high data fidelity between rotating and stationary structures. Up to now, there have been numerous approaches used for signal and data transfer utilizing a slip ring such as metal contacts, wires, radio transmission, and even liquid media. However, all suffer from drawbacks such as data transfer speed limitations, reliability, stability, electro-magnetic interference and durability. The purpose of the current research is to break through these basic limitations using an optical solution, thereby improving performance in current slip ring applications. This dissertation introduces a novel Electro-Optical Hybrid Slip Ring technology, which makes "through the air" digital-optical communication between stationary and rotating systems a reality with high data transfer speed, better reliability and low interference susceptibility

  8. Ringing Artefact Reduction By An Efficient Likelihood Improvement Method

    Science.gov (United States)

    Fuderer, Miha

    1989-10-01

    In MR imaging, the extent of the acquired spatial frequencies of the object is necessarily finite. The resulting image shows artefacts caused by "truncation" of its Fourier components. These are known as Gibbs artefacts or ringing artefacts. These artefacts are particularly. visible when the time-saving reduced acquisition method is used, say, when scanning only the lowest 70% of the 256 data lines. Filtering the data results in loss of resolution. A method is described that estimates the high frequency data from the low-frequency data lines, with the likelihood of the image as criterion. It is a computationally very efficient method, since it requires practically only two extra Fourier transforms, in addition to the normal. reconstruction. The results of this method on MR images of human subjects are promising. Evaluations on a 70% acquisition image show about 20% decrease of the error energy after processing. "Error energy" is defined as the total power of the difference to a 256-data-lines reference image. The elimination of ringing artefacts then appears almost complete..

  9. Cabling design of booster and storage ring construction progress of TPS

    International Nuclear Information System (INIS)

    Wong, Y.-S.; Liu, K.-B.; Liu, C.-Y.; Wang, B.-S.

    2017-01-01

    The 2012 Taiwan Photon Source (TPS) cable construction project started after 10 months to complete the cable laying and installation of power supply. The circumference of the booster ring (BR) is 496.8 m, whereas that of the storage ring (SR) is 518.4 m. Beam current is set to 500 mA at 3.3 GeV. The paper on grounding systems discusses the design of the ground wire (< 0.2 Ω) with low impedance, power supply of the accelerator and cabling tray. The flow and size of the ground current are carefully evaluated to avoid grounded current from flowing everywhere, which causes interference problems. In the design of the TPS, special shielding will be established to isolate the effects of electromagnetic interference on the magnet and ground current. Booster ring dipoles are connected by a series of 54-magnet bending dipole; the cable size of its stranded wire measures 250 mm"2, with a total length of 5000 m. Booster ring and storage ring quadrupoles have 150 magnets; the cable size of their stranded wire is 250 mm"2, with a total length of 17000 m. Storage ring dipole consists of 48 magnets; the cable size of its stranded wire is 325 mm"2, with a total length of 6000 m. This study discusses the power supply cabling design of the storage ring and booster ring construction progress of TPS. The sections of this paper are divided into discussions of the construction of the control and instrument area, cabling layout of booster ring and storage ring, as well as the installation and commission machine. This study also discusses the use of a high-impedance meter to determine the effect of cabling insulation and TPS power supply machine on energy transfer to ensure the use of safe and correct magnet.

  10. ASSOCIATIVE RINGS SOLVED AS LIE RINGS

    Directory of Open Access Journals (Sweden)

    M. B. Smirnov

    2011-01-01

    Full Text Available The paper has proved that an associative ring which is solvable of a n- class as a Lie ring has a nilpotent ideal of the nilpotent class not more than 3×10n–2  and a corresponding quotient ring satisfies an identity [[x1, x2, [x3, x4

  11. Beam-beam effects in high energy e+e- storage rings: resonant amplification of vertical dimensions for flat beams

    International Nuclear Information System (INIS)

    Bambade, P.

    1984-06-01

    In this thesis, we present a phenomenological study of the beam-beam effect in e + e - storage rings. We are in particular interested in the blow-up of the vertical dimension observed in this kind of accelerator. A detailed analysis of the electromagnetic field generated by the very flat bunches stored, and seen by the counter-rotating particles shows that two-dimensional non-linear resonances, which couple vertical and horizontal betatron oscillations, play a very important role. Moreover, the ''weak beam-strong beam'' approximation holds rather well in the case of very flat bunches. Perturbative analysis enables us to predict the effects from the strongest coupling resonance: 20sub(x)-20sub(y) = integer. We find that mainly the tails of the vertical distribution are affected, and we give a criterion concerning the optimal distance to this resonance in the case of a storage ring such as LEP. Finally, the results and in particular the validity of the single resonance approximation are checked through a numerical simulation [fr

  12. Optics Design and Performance of an Ultra-Low Emittance Damping Ring for the Compact Linear Collider

    CERN Document Server

    Korostelev, M S

    2006-01-01

    A high-energy (0.5-3.0 TeV centre of mass) electron-positron Compact Linear Collider (CLIC) is being studied at CERN as a new physics facility. The design study has been optimized for 3 TeV centre-of-mass energy. Intense bunches injected into the main linac must have unprecedentedly small emittances to achieve the design luminosity 1035cm-2s-1 required for the physics experiments. The positron and electron bunch trains will be provided by the CLIC injection complex. This thesis describes an optics design and performance of a positron damping ring developed for producing such ultra-low emittance beam. The linear optics of the CLIC damping ring is optimized by taking into account the combined action of radiation damping, quantum excitation and intrabeam scattering. The required beam emittance is obtained by using a TME (Theoretical Minimum Emittance) lattice with compact arcs and short period wiggler magnets located in dispersionfree regions. The damping ring beam energy is chosen as 2.42 GeV. The lattice featu...

  13. CESAR, 2 MeV electron storage ring.

    CERN Multimedia

    CERN PhotoLab

    1967-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  14. Controllable continuous evolution of electronic states in a single quantum ring

    Science.gov (United States)

    Chakraborty, Tapash; Manaselyan, Aram; Barseghyan, Manuk; Laroze, David

    2018-02-01

    An intense terahertz laser field is shown to have a profound effect on the electronic and optical properties of quantum rings where the isotropic and anisotropic quantum rings can now be treated on equal footing. We have demonstrated that in isotropic quantum rings the laser field creates unusual Aharonov-Bohm oscillations that are usually expected in anisotropic rings. Furthermore, we have shown that intense laser fields can restore the isotropic physical properties in anisotropic quantum rings. In principle, all types of anisotropies (structural, effective masses, defects, etc.) can evolve as in isotropic rings in our present approach. Most importantly, we have found a continuous evolution of the energy spectra and intraband optical characteristics of structurally anisotropic quantum rings to those of isotropic rings in a controlled manner with the help of a laser field.

  15. High-Q contacted ring microcavities with scatterer-avoiding “wiggler” Bloch wave supermode fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yangyang, E-mail: yangyang.liu@colorado.edu; Popović, Miloš A., E-mail: milos.popovic@colorado.edu [Nanophotonic Systems Laboratory, Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309 (United States)

    2014-05-19

    High-Q ring resonators with contacts to the waveguide core provide a versatile platform for various applications in chip-scale optomechanics, thermo-, and electro-optics. We propose and demonstrate azimuthally periodic contacted ring resonators based on multi-mode Bloch matching that support contacts on both the inner and outer radius edges with small degradation to the optical quality factor (Q). Radiative coupling between degenerate modes of adjacent radial spatial order leads to imaginary frequency (Q) splitting and a scatterer avoiding high-Q “wiggler” supermode field. We experimentally measure Qs up to 258 000 in devices fabricated in a silicon device layer on buried oxide undercladding and up to 139 000 in devices fully suspended in air using an undercut step. Wiggler supermodes are true modes of the microphotonic system that offer additional degrees of freedom in electrical, thermal, and mechanical design.

  16. Ring current proton decay by charge exchange

    Science.gov (United States)

    Smith, P. H.; Hoffman, R. A.; Fritz, T.

    1975-01-01

    Explorer 45 measurements during the recovery phase of a moderate magnetic storm have confirmed that the charge exchange decay mechanism can account for the decay of the storm-time proton ring current. Data from the moderate magnetic storm of 24 February 1972 was selected for study since a symmetrical ring current had developed and effects due to asymmetric ring current losses could be eliminated. It was found that after the initial rapid decay of the proton flux, the equatorially mirroring protons in the energy range 5 to 30 keV decayed throughout the L-value range of 3.5 to 5.0 at the charge exchange decay rate calculated by Liemohn. After several days of decay, the proton fluxes reached a lower limit where an apparent equilibrium was maintained, between weak particle source mechanisms and the loss mechanisms, until fresh protons were injected into the ring current region during substorms. While other proton loss mechanisms may also be operating, the results indicate that charge exchange can entirely account for the storm-time proton ring current decay, and that this mechanism must be considered in all studies involving the loss of proton ring current particles.

  17. Ring-Expansion/Contraction Radical Crossover Reactions of Cyclic Alkoxyamines: A Mechanism for Ring Expansion-Controlled Radical Polymerization

    Directory of Open Access Journals (Sweden)

    Atsushi Narumi

    2018-06-01

    Full Text Available Macrocyclic polymers present an important class of macromolecules, displaying the reduced radius of gyration or impossibility to entangle. A rare approach for their synthesis is the ring expansion-controlled radical “vinyl” polymerization, starting from a cyclic alkoxyamine. We here describe ring-expansion radical crossover reactions of cyclic alkoxyamines which run in parallel to chain-propagation reactions in the polymerization system. The radical crossover reactions extensively occurred at 105–125 °C, eventually producing high molecular weight polymers with multiple inherent dynamic covalent bonds (NOC bonds. A subsequent ring-contraction radical crossover reaction and the second ring-expansion radical crossover reaction are also described. The major products for the respective three stages were shown to possess cyclic morphologies by the molecular weight profiles and the residual ratios for the NOC bonds (φ in %. In particular, the high φ values ranging from ca. 80% to 98% were achieved for this cyclic alkoxyamine system. This result verifies the high availability of this system as a tool demonstrating the ring-expansion “vinyl” polymerization that allows them to produce macrocyclic polymers via a one-step vinyl polymerization.

  18. Formation of ring-patterned nanoclusters by laser–plume interaction

    International Nuclear Information System (INIS)

    Sivayoganathan, Mugunthan; Tan Bo; Venkatakrishnan, Krishnan

    2013-01-01

    This article reports for the first time a unique study performed to regulate the ring diameter of nanoclusters fabricated during femtosecond laser ablation of solids and a mechanism is proposed for the formation of those ring clusters. The ring nanoclusters are made out of nanoparticles with a range of 10–30 nm. Our experimental studies showed the synthesis of ring nanoclusters with random diameter distribution on metals, nonmetals, and semiconductors, such as titanium, aluminum, glasses, ceramics, graphite, and silicon. To regulate the ring size, the effects of laser parameters, such as wavelength, pulse duration, pulse energy, and repetition rate on the ring diameter are analyzed. The influence of ablated materials and the background gas on ring size is also elaborated in this article. The motion of plume species under the influence of ponderomotive force on free electrons possibly played a key role in the formation of the ring-patterned nanoclusters. This study could help to understand the fundamentals in laser ablative nanosynthesis as well as to produce nanostructures with organized ring diameter that controls the density and porosity of those 3D nanostructures.

  19. The beam slow extraction from a magnetic ring of Moscow meson facility

    International Nuclear Information System (INIS)

    Gusev, O.A.; Malitsky, N.D.; Severgin, Yu.P.; Titov, V.A.; Shukeilo, I.A.; Aseev, V.N.; Grachev, M.I.; Lobashev, V.M.; Ostroumov, P.N.; Ponomaryov, O.V.

    1990-01-01

    The beam slow extraction from the circular accelerators or stretcher rings is generally realized by the resonant excitation of betratron oscillations. A precise betatron frequency control is proved to be quite necessary for high-efficient slow ejection. The Coulomb field turns out to have a significant influence upon the slow extraction from the high-current medium energy proton storage rings. It prevents resonant excitation at a reasonable rate and reduces the ejection efficiency. The proton storage ring of Moscow meson facility is an example of a stretcher with a noticeable beam space charge. The detailed investigation of the resonant ejection, having been performed for our stretcher, resulted in the conclusion that extracted beam average current should be limited by the value of 50 mA, which is only 10% of the linac design current. The search for the alternative version to the resonant ejection made us to analyze in details and to develop an old-fashioned method, based on the radial betatron oscillation excitation while the beam is being gradually shifted onto the thin target. (author) 5 refs., 4 figs

  20. High Precision Optical Observations of Space Debris in the Geo Ring from Venezuela

    Science.gov (United States)

    Lacruz, E.; Abad, C.; Downes, J. J.; Casanova, D.; Tresaco, E.

    2018-01-01

    We present preliminary results to demonstrate that our method for detection and location of Space Debris (SD) in the geostationary Earth orbit (GEO) ring, based on observations at the OAN of Venezuela is of high astrometric precision. A detailed explanation of the method, its validation and first results is available in (Lacruz et al. 2017).

  1. Pseudo-single-bunch mode for a 100 MHz storage ring serving soft X-ray timing experiments

    Science.gov (United States)

    Olsson, T.; Leemann, S. C.; Georgiev, G.; Paraskaki, G.

    2018-06-01

    At many storage rings for synchrotron light production there is demand for serving both high-flux and timing users simultaneously. Today this is most commonly achieved by operating inhomogeneous fill patterns, but this is not preferable for rings that employ passive harmonic cavities to damp instabilities and increase Touschek lifetime. For these rings, inhomogeneous fill patterns could severely reduce the effect of the harmonic cavities. It is therefore of interest to develop methods to serve high-flux and timing users simultaneously without requiring gaps in the fill pattern. One such method is pseudo-single-bunch (PSB), where one bunch in the bunch train is kicked onto another orbit by a fast stripline kicker. The light emitted from the kicked bunch can then be separated by an aperture in the beamline. Due to recent developments in fast kicker design, PSB operation in multibunch mode is within reach for rings that operate with a 100 MHz RF system, such as the MAX IV and Solaris storage rings. This paper describes machine requirements and resulting performance for such a mode at the MAX IV 1.5 GeV storage ring. A solution for serving all beamlines is discussed as well as the consequences of beamline design and operation in the soft X-ray energy range.

  2. Novel Fiber-Optic Ring Acoustic Emission Sensor.

    Science.gov (United States)

    Wei, Peng; Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

    2018-01-13

    Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

  3. Experimental investigation of electron cooling and stacking of lead ions in a low energy accumulation ring

    CERN Document Server

    Bosser, Jacques; Chanel, M; Hill, C; Lombardi, A M; MacCaferri, R; Maury, S; Möhl, D; Molinari, G; Rossi, S; Tanke, E; Tranquille, G; Vretenar, Maurizio

    1999-01-01

    This report gives the results of a programme of experimental investigations, which were carried out to test stacking of lead ions in a storage ring (the former Low Energy Antiproton Ring, LEAR) at 4.2 MeV per nucleon. The motivation was to demonstrate the feasibility of gaining the large factor in the phase-space density required for injection into the LHC. In the first part of the report, the layout of the experiments is described, the choice of the parameters of the electron cooling system used for stacking is reported and the multi-turn injection using horizontal- and longitudinal- (and in the final project also vertical-) phase space is discussed. In the second part the experimental results are presented. Factors of vital importance are the stacking efficiency, the beam life-time and the cooling time of the ions. The beam decay owing to charge exchange with the residual gas and to recombination by the capture of cooling electrons was intensively studied. Beam instabilities and space-charge effects in the ...

  4. CESR-c Performance of a Wiggler-Dominated Storage Ring

    CERN Document Server

    Temnykh, Alexander

    2005-01-01

    CESR-c operates now as a Wiggler-Dominated Storage Ring extending the lowest operating energy to 1.5GeV/beam. To improve beam stability at low energy, 12 super-ferric wiggler magnets with total length of 15m and 2.1T maximum field were installed in the ring. They cause ~90% of total beam radiation lost and increase radiation damping rate by factor 10 from ~3 to 40 Hz. However, the field of the wiggler magnets not only initiates the radiation, but potentially affects beam dynamics. The latter was an issue of a great concern from the planning the CESR-c project. In this paper we describe general performance of CESR-c and report the results of an experimental study on some aspects of beam dynamics. Comparisons are made between the experimental data and the model prediction. We find that all parameters, which are critically dependent on wigglers, such as beam properties and ring nonlinearity, are in good agreement with those calculated from the model. This validates the ring and wiggler models and justifies our d...

  5. Propellers in Saturn's rings

    Science.gov (United States)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2013-12-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We show evidence that B ring seems to harbor two distinct populations of propellers: "big" propellers covering tens of degrees in azimuth situated in the densest part of B ring, and "small" propellers in less dense inner B ring that are similar in size and shape to known A ring propellers. The population of "big" propellers is exemplified with a single object which is observed for 5 years of Cassini data. The object is seen as a very elongated bright stripe (40 degrees wide) in unlit Cassini images, and dark stripe in lit geometries. In total we report observing the feature in images at 18 different epochs between 2005 and 2010. In UVIS occultations we observe this feature as an optical depth depletion in 14 out of 93 occultation cuts at corrotating longitudes compatible with imaging data. Combining the available Cassini data we infer that the object is a partial gap located at r=112,921km embedded in the high optical depth region of the B ring. The gap moves at Kepler speed appropriate for its radial location. Radial offsets of the gap locations in UVIS occultations are consistent with an asymmetric propeller shape. The asymmetry of the observed shape is most likely a consequence of the strong surface mass density gradient, as the feature is located at an edge between

  6. High duty factor structures for e+e- storage rings

    International Nuclear Information System (INIS)

    Allen, M.A.; Karvonen, L.G.

    1976-01-01

    The next generation of e + e - storage rings will need rf systems similar to those required for a continuous-duty linac of over 50 MeV. For the PEP Storage Ring at 18 GeV, it is presently planned to provide a peak accelerating voltage of 77 MV in 18 aluminum accelerating structures, each structure consisting of five slot-coupled cells operating in the π mode. The power dissipation will be 100 kW per cell for a total of 500 kW per five-cell structure at 353 MHz. A two-cell model was designed and built to dissipate 100 kW per cell or a total of 200 kW. This structure was powered (cw) to over 100 kW per cell, and detailed calorimetric data were taken and compared with the original heat transfer calculations. The power level achieved corresponds to a peak accelerating field (transit-time factor included) in the two-cell model of 0.8 MV per cell or 1.9 MV/meter. Operating experience with the SPEAR five-cell structure is discussed. The four SPEAR structures are each designed to operate with wall losses of 75 kW and up to 50 kW into the stored beam. Power to each structure is provided by a 125-kW high-efficiency four-cavity klystron. No isolation has been used and the resulting interaction between the accelerating structures, klystrons, and the stored beams is discussed

  7. 25Gb/s 1V-driving CMOS ring modulator with integrated thermal tuning.

    Science.gov (United States)

    Li, Guoliang; Zheng, Xuezhe; Yao, Jin; Thacker, Hiren; Shubin, Ivan; Luo, Ying; Raj, Kannan; Cunningham, John E; Krishnamoorthy, Ashok V

    2011-10-10

    We report a high-speed ring modulator that fits many of the ideal qualities for optical interconnect in future exascale supercomputers. The device was fabricated in a 130 nm SOI CMOS process, with 7.5 μm ring radius. Its high-speed section, employing PN junction that works at carrier-depletion mode, enables 25 Gb/s modulation and an extinction ratio >5 dB with only 1V peak-to-peak driving. Its thermal tuning section allows the device to work in broad wavelength range, with a tuning efficiency of 0.19 nm/mW. Based on microwave characterization and circuit modeling, the modulation energy is estimated ~7 fJ/bit. The whole device fits in a compact 400 μm2 footprint.

  8. Demonstration of electron clearing effect by means of a clearing electrode in high-intensity positron ring

    International Nuclear Information System (INIS)

    Suetsugu, Y.; Fukuma, H.; Wang, L.; Pivi, M.; Morishige, A.; Suzuki, Y.; Tsukamoto, M.; Tsuchiya, M.

    2009-01-01

    In the beam pipe of high-intensity positron/proton storage rings, undesired electron clouds may be first produced by photoelectrons and the ionization of residual gases; then the clouds increase by the secondary electron emission. In this study, a strip-line clearing electrode has been developed to mitigate the electron-cloud effect in high-intensity positron/proton storage rings. The electrode is composed of a thin tungsten layer with a thickness of 0.1 mm formed on a thin alumina ceramic layer with a thickness of 0.2 mm. The narrow alumina gap between the electrode and the beam pipe decreases the beam impedance and also enhances the heat transfer from the electrode to the beam pipe. A test model has been installed in the KEK B-factory (KEKB) positron ring, along with an electron monitor with a retarding grid. The electron density in a field free region decreased by one order of magnitude was observed on the application of ±500 V to the electrode at a beam current of 1.6 A with 1585 bunches. The reduction in the electron density was more drastic in a vertical magnetic field of 0.77 T, that is, the electron density decreased by several orders by applying +500 V to the electrode at the same beam current. This experiment is the first experiment demonstrating the principle of the clearing electrode that is used to mitigate the electron-cloud effect in a positron ring.

  9. Development of high gradient superconducting radio frequency cavities for international linear collider and energy recovery linear accelerator

    International Nuclear Information System (INIS)

    Saito, Kenji; Furuta, Fumio; Saeki, Takayuki

    2009-01-01

    Superconducting radio frequency (SRF) cavities were used for storage rings like TRISTAN at KEK, HERA at DESY and LEP-II at CERN in 1990-2000. This technology has been accepted as a common accelerator technology. In August 2004, ITPR recommended an electron/positron linear collider based on SRF technology for the future high energy physics. ICFA accepted the recommendation and named it ILC (International Linear Collider). SRF cavities have a very unique feature due to its very small surface resistance. Energy recovery is another very exciting application. Many laboratories are proposing ERL (Energy Recovery LINAC) as a next bright photon source. In these accelerators, production of SRF cavities with reliably high performance is the most important issue. In this paper the activities of ILC high gradient cavities will be introduced. ERL activity will be briefly presented. (author)

  10. Development of High Gradient Superconducting Radio Frequency Cavities for International Linear Collider and Energy Recovery Linear Accelerator

    Science.gov (United States)

    Saito, Kenji; Furuta, Fumio; Saeki, Takayuki

    Superconducting radio frequency (SRF) cavities were used for storage rings like TRISTAN at KEK, HERA at DESY and LEP-II at CERN in 1990-2000. This technology has been accepted as a common accelerator technology. In August 2004, ITPR recommended an electron/positron linear collider based on SRF technology for the future high energy physics. ICFA accepted the recommendation and named it ILC (International Linear Collider). SRF cavities have a very unique feature due to its very small surface resistance. Energy recovery is another very exciting application. Many laboratories are proposing ERL (Energy Recovery LINAC) as a next bright photon source. In these accelerators, production of SRF cavities with reliably high performance is the most important issue. In this paper the activities of ILC high gradient cavities will be introduced. ERL activity will be briefly presented.

  11. Ground Movement in SSRL Ring

    International Nuclear Information System (INIS)

    Sunikumar, Nikita

    2011-01-01

    Users of the Stanford Synchrotron Radiation Lightsource (SSRL) are being affected by diurnal motion of the synchrotron's storage ring, which undergoes structural changes due to outdoor temperature fluctuations. In order to minimize the effects of diurnal temperature fluctuations, especially on the vertical motion of the ring floor, scientists at SSRL tried three approaches: painting the storage ring white, covering the asphalt in the middle of the ring with highly reflective Mylar and installing Mylar on a portion of the ring roof and walls. Vertical motion in the storage ring is measured by a Hydrostatic Leveling System (HLS), which calculates the relative height of water in a pipe that extends around the ring. The 24-hr amplitude of the floor motion was determined using spectral analysis of HLS data, and the ratio of this amplitude before and after each experiment was used to quantitatively determine the efficacy of each approach. The results of this analysis showed that the Mylar did not have any significant effect on floor motion, although the whitewash project did yield a reduction in overall HLS variation of 15 percent. However, further analysis showed that the reduction can largely be attributed to a few local changes rather than an overall reduction in floor motion around the ring. Future work will consist of identifying and selectively insulating these local regions in order to find the driving force behind diurnal floor motion in the storage ring.

  12. Coherent instability of the heavy ion beam in the storage ring

    International Nuclear Information System (INIS)

    Noda, A.

    1981-01-01

    The storage ring as the final part of a driver for heavy ion fusion is required to provide heavy ions (A asymptotically equals 200) with energy of 5 -- 10 GeV and such a high intensity as 1 -- 6 x 10 15 ions/pulse. So as to raise the number of ions which can be accumulated in a ring, singlly charged heavy ion is used for its relatively smaller incoherent space charge force compared with higher charge states. The intensity limit due to incoherent space charge force is 0.7 -- 1.4 x 10 15 ions for U 1 + . Much more severe limits exist due to coherent motion of heavy ion beams (0.8 -- 2 x 10 13 for longitudinal motion and 0.9 -- 1.1 x 10 12 for transverse motion), because of the relatively lower velocity of the accumulated ions. It seems unrealistic to use a lot of rings in order to operate below such intensity limits of the above instability. Therefore the number of the storage rings is constrained within a reasonable value (3 -- 7) and the possibility of compressing the bunches of heavy ion beams before the instability grows fatally large is studied. (author)

  13. FEL radiation power available in electron storage rings

    International Nuclear Information System (INIS)

    Miyahara, Yoshikazu

    1994-01-01

    FEL radiation power available in electron storage rings was studied in the small signal regime in considering the increase of the energy spread of the electron beam caused by the FEL interaction and the decrease of the FEL gain with the increase of the energy spread in addition to the radiation damping and the quantum excitation. All these effects were considered separately, and combined with FEL power equations. The radiation power available was expressed explicitly with the parameters of the storage ring, the wiggler and the mirrors. The transient process of FEL lasing is simulated with the power equations. A rough estimation is made of the radiation power available by the FEL at different beam energies, and optimization of FEL parameters for a higher radiation power is discussed. ((orig.))

  14. Self-assembly of concentric quantum double rings.

    Science.gov (United States)

    Mano, Takaaki; Kuroda, Takashi; Sanguinetti, Stefano; Ochiai, Tetsuyuki; Tateno, Takahiro; Kim, Jongsu; Noda, Takeshi; Kawabe, Mitsuo; Sakoda, Kazuaki; Kido, Giyuu; Koguchi, Nobuyuki

    2005-03-01

    We demonstrate the self-assembled formation of concentric quantum double rings with high uniformity and excellent rotational symmetry using the droplet epitaxy technique. Varying the growth process conditions can control each ring's size. Photoluminescence spectra emitted from an individual quantum ring complex show peculiar quantized levels that are specified by the carriers' orbital trajectories.

  15. Quantized levitation states of superconducting multiple-ring systems

    International Nuclear Information System (INIS)

    Haley, S.B.; Fink, H.J.

    1996-01-01

    The quantized levitation, trapped, and suspension states of a magnetic microsphere held in equilibrium by two fixed superconducting (SC) microrings are calculated by minimizing the free energy of the system. Each state is a discrete function of two independent fluxoid quantum numbers of the rings. When the radii of the SC rings are of the same order as the Ginzburg-Landau coherence length ξ(T), the system exhibits a small set of gravity and temperature-dependent levels. The levels of a weakly magnetized particle are sensitive functions of the gravitational field, indicating potential application as an accelerometer, and for trapping small magnetic particles in outer space or on Earth. The equilibrium states of a SC ring levitated by another SC ring are also calculated. copyright 1996 The American Physical Society

  16. Bernstein instability driven by thermal ring distribution

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Peter H., E-mail: yoonp@umd.edu [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Hadi, Fazal; Qamar, Anisa [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan)

    2014-07-15

    The classic Bernstein waves may be intimately related to banded emissions detected in laboratory plasmas, terrestrial, and other planetary magnetospheres. However, the customary discussion of the Bernstein wave is based upon isotropic thermal velocity distribution function. In order to understand how such waves can be excited, one needs an emission mechanism, i.e., an instability. In non-relativistic collision-less plasmas, the only known Bernstein wave instability is that associated with a cold perpendicular velocity ring distribution function. However, cold ring distribution is highly idealized. The present Brief Communication generalizes the cold ring distribution model to include thermal spread, so that the Bernstein-ring instability is described by a more realistic electron distribution function, with which the stabilization by thermal spread associated with the ring distribution is demonstrated. The present findings imply that the excitation of Bernstein waves requires a sufficiently high perpendicular velocity gradient associated with the electron distribution function.

  17. Bernstein instability driven by thermal ring distribution

    International Nuclear Information System (INIS)

    Yoon, Peter H.; Hadi, Fazal; Qamar, Anisa

    2014-01-01

    The classic Bernstein waves may be intimately related to banded emissions detected in laboratory plasmas, terrestrial, and other planetary magnetospheres. However, the customary discussion of the Bernstein wave is based upon isotropic thermal velocity distribution function. In order to understand how such waves can be excited, one needs an emission mechanism, i.e., an instability. In non-relativistic collision-less plasmas, the only known Bernstein wave instability is that associated with a cold perpendicular velocity ring distribution function. However, cold ring distribution is highly idealized. The present Brief Communication generalizes the cold ring distribution model to include thermal spread, so that the Bernstein-ring instability is described by a more realistic electron distribution function, with which the stabilization by thermal spread associated with the ring distribution is demonstrated. The present findings imply that the excitation of Bernstein waves requires a sufficiently high perpendicular velocity gradient associated with the electron distribution function

  18. Simulations of Bunch Merging in a Beta Beam Decay Ring

    CERN Document Server

    Heinrich, Daniel Christopher; Chance, Antoine

    2011-01-01

    To further study neutrino oscillation properties a Beta Beam facility has been proposed. Beta decaying ions with high kinetic energy are stored in a storage ring ("Decay Ring") with straight sections to create pure focused (anti) electron neutrino beams. However to reach high sensitivity to neutrino oscillation parameters in the experiment the bunched beam intensity and duty cycle in the DR have to be optimized. The first CERN-based scenario, using 6He and 18Ne as neutrino sources, has been studied using a bunch merging RF scheme. Two RF cavities at different frequencies are used to capture newly injected bunches and then merge them into the stored bunches. It was shown that this scheme could satisfy the requirements on intensity and duty cycle set by the experiment. This merging scheme has now been revised with new simulation software providing new results for 6He and 18Ne. Furthermore bunch merging has been studied for the second CERN-based scenario using 8Li and 8B.

  19. Theory of electron energy spectrum and Aharonov-Bohm effect in self-assembled Inx Ga1-x As quantum rings in GaAs

    NARCIS (Netherlands)

    Fomin, V.M.; Gladilin, V.N.; Klimin, S.N.; Devreese, J.T.; Kleemans, N.A.J.M.; Koenraad, P.M.

    2007-01-01

    We analyze theoretically the electron energy spectrum and the magnetization of an electron in a strained Inx Ga1-x As GaAs self-assembled quantum ring (SAQR) with realistic parameters, determined from the cross-sectional scanning-tunneling microscopy characterization of that nanostructure. The SAQRs

  20. Transition between vortex rings and MAP solutions for electrically charged magnetic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Khai-Ming; Soltanian, Amin; Teh, Rosy [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    2014-03-05

    We consider the bifurcation and transition of axially symmetric monopole-antimonopole pair (MAP) and vortex ring solutions in the presence of electric charge for the SU(2) Yang-Mills-Higgs field theory. Here we investigate the properties of MAP/vortex ring solutions with n = 3,η = 0.65, for different Higgs field strength λ. For λ < 4.93, there is only one fundamental branch of vortex ring solution, but at the critical value of λ{sub b} = 4.93, branching happens and 2 sets of new solutions appeared. The new branch with less energy is a full MAP solution while the branch with higher energy contains MAP at the beginning and separation between poles of MAP on the z-axis reduces gradually and at another critical value of λ{sub t} = 14.852, they merge together at z = 0. Beyond this point the solutions change to the vortex ring solutions and a transitions between MAP and vortex ring solutions happens at this branch.

  1. Novel Fiber-Optic Ring Acoustic Emission Sensor

    Directory of Open Access Journals (Sweden)

    Peng Wei

    2018-01-01

    Full Text Available Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

  2. Preliminary Design of an Inductive Adder for CLIC Damping Rings

    CERN Document Server

    Holma, J

    2011-01-01

    The Compact Linear Collider (CLIC) study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC damping rings will produce ultra-low emittance beam, with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse power modulators for the damping rings kickers must provide extremely flat, high-voltage, pulses: specifications call for a 160 ns duration flattop of 12.5 kV, 250 A, with a combined ripple and droop of not more than ±0.02 %. A solid-state modulator, the inductive adder, is a very promising approach to meeting the demanding specifications; this topology allows the use of both digital and analogue modulation. To effectively use modulation techniques to achieve such low ripple and droop requires an in-depth knowledge of the behaviour of the solid-state switching components and their gate drivers, as well as a good understanding of the overa...

  3. Enhanced spin wave propagation in magnonic rings by bias field modulation

    Science.gov (United States)

    Venkat, G.; Venkateswarlu, D.; Joshi, R. S.; Franchin, M.; Fangohr, H.; Anil Kumar, P. S.; Prabhakar, A.

    2018-05-01

    We simulate the spin wave (SW) dynamics in ring structures and obtain the ω - k dispersion relations corresponding to the output waveguide. Different bias field configurations affect the transfer of SW power from one arm of the structure to the other arm. To this end, we show that circular or radial bias fields are more suitable for energy transfer across the ring than the conventional horizontal bias field Hx. The SW dispersion shows that modes excited, when the bias field is along the ring radius, are almost 10 dB higher in power when compared to the modal power in the case of Hx. This is also corroborated by the SW energy density in the receiving stub.

  4. Planning and Prototyping for a Storage Ring Measurement of the Proton Electric Dipole Moment

    Energy Technology Data Exchange (ETDEWEB)

    Talman, Richard [Cornell Univ., Ithaca, NY (United States)

    2015-07-01

    Electron and proton EDM's can be measured in "frozen spin" (with the beam polarization always parallel to the orbit, for example) storage rings. For electrons the "magic" kinetic energy at which the beam can be frozen is 14.5 MeV. For protons the magic kinetic energy is 230 MeV. The currently measured upper limit for the electron EDM is much smaller than the proton EDM upper limit, which is very poorly known. Nevertheless, because the storage ring will be an order of magnitude cheaper, a sensible plan is to first build an all-electric electron storage ring as a prototype. Such an electron ring was successfully built at Brookhaven, in 1954, as a prototype for their AGS ring. This leaves little uncertainty concerning the cost and performance of such a ring. (This is documentedin one of the Physical Review papers mentioned above.)

  5. Periodic seasonal variation of magnets level of the STB ring

    International Nuclear Information System (INIS)

    Takahashi, Shigenobu

    2003-01-01

    The Stretcher-Booster (STB) ring, a 1.2 GeV electron synchrotron, was completed in December, 1997 at the Laboratory of Nuclear Sciences (LNS), Tohoku University. The total weight more than 400 tons were placed near the STB ring, such as concrete blocks for radiation shielding and a spectrometer magnet for nuclear physics experiments after the completion of the STB ring. Re-surveying of magnets alignment was started after 2000. Very recently a new building of an experimental hall was constructed close to the building of the STB ring for use of high energy γ-ray from the electron beam. The building will give rise the changes of magnet levels due to its seasonal distortion. The measurements of the magnet level after construction are continued as well as an expected change of the closed orbit distortion (COD) in the STB ring. The serious influence of the variation of the magnet level may be a change of the beam orbit of extracted beam in the stretcher operation. Difference of the orbit distortion reaches more than 5 mm. Correlation between the COD and the seasonal change of the magnet position is not clear at the moment. However, the machine operation and the beam diagnostics are getting better recently. Continuous surveying of the magnet level will be a useful data for a feed forward correction of the beam orbit. Future subjects and prospects are discussed on surveying. (Y. Tanaka)

  6. Photocapacitance study of type-II GaSb/GaAs quantum ring solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wagener, M. C.; Botha, J. R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Carrington, P. J.; Krier, A. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

    2014-01-07

    In this study, the density of states associated with the localization of holes in GaSb/GaAs quantum rings are determined by the energy selective charging of the quantum ring distribution. The authors show, using conventional photocapacitance measurements, that the excess charge accumulated within the type-II nanostructures increases with increasing excitation energies for photon energies above 0.9 eV. Optical excitation between the localized hole states and the conduction band is therefore not limited to the Γ(k = 0) point, with pseudo-monochromatic light charging all states lying within the photon energy selected. The energy distribution of the quantum ring states could consequently be accurately related from the excitation dependence of the integrated photocapacitance. The resulting band of localized hole states is shown to be well described by a narrow distribution centered 407 meV above the GaAs valence band maximum.

  7. Functional roles of the pepper RING finger protein gene, CaRING1, in abscisic acid signaling and dehydration tolerance.

    Science.gov (United States)

    Lim, Chae Woo; Hwang, Byung Kook; Lee, Sung Chul

    2015-09-01

    Plants are constantly exposed to a variety of biotic and abiotic stresses, which include pathogens and conditions of high salinity, low temperature, and drought. Abscisic acid (ABA) is a major plant hormone involved in signal transduction pathways that mediate the defense response of plants to abiotic stress. Previously, we isolated Ring finger protein gene (CaRING1) from pepper (Capsicum annuum), which is associated with resistance to bacterial pathogens, accompanied by hypersensitive cell death. Here, we report a new function of the CaRING1 gene product in the ABA-mediated defense responses of plants to dehydration stress. The expression of the CaRING1 gene was induced in pepper leaves treated with ABA or exposed to dehydration or NaCl. Virus-induced gene silencing of CaRING1 in pepper plants exhibited low degree of ABA-induced stomatal closure and high levels of transpirational water loss in dehydrated leaves. These led to be more vulnerable to dehydration stress in CaRING1-silenced pepper than in the control pepper, accompanied by reduction of ABA-regulated gene expression and low accumulation of ABA and H2O2. In contrast, CaRING1-overexpressing transgenic plants showed enhanced sensitivity to ABA during the seedling growth and establishment. These plants were also more tolerant to dehydration stress than the wild-type plants because of high ABA accumulation, enhanced stomatal closure and increased expression of stress-responsive genes. Together, these results suggest that the CaRING1 acts as positive factor for dehydration tolerance in Arabidopsis by modulating ABA biosynthesis and ABA-mediated stomatal closing and gene expression.

  8. The design of the Spectrometer Ring at the HIAF

    Science.gov (United States)

    Wu, B.; Yang, J. C.; Xia, J. W.; Yan, X. L.; Hu, X. J.; Mao, L. J.; Sheng, L. N.; Wu, J. X.; Yin, D. Y.; Chai, W. P.; Shen, G. D.; Ge, W. W.; Wang, G.; Zhao, H.; Ruan, S.; Ma, X. W.; Wang, M.; Litvinov, S.; Wen, W. Q.; Chen, X. C.; Chen, R. J.; Tang, M. T.; Wu, W.; Luo, C.; Zhao, T. C.; Shi, C. F.; Fu, X.; Liu, J.; Liang, L.

    2018-02-01

    The Spectrometer Ring (SRing) is an essential part of the High Intensity heavy-ion Accelerator Facility project (HIAF) in China. It is designed as a multi-functional experimental storage ring, which will be able to operate in three ion optical operation modes. The SRing will be used as a time-of-flight mass spectrometer for short-lived, especially neutron-rich nuclei. It will also be used to collect and cool Rare Isotope Beams (RIBs) or highly-charged stable ion beams for nuclear and atomic physics experiments. The design magnetic rigidity is in the range 1.5 to 15 Tm. The beam cooling system consists of stochastic cooling and electron cooling devices. With a help of an electron cooler, stored ions will be decelerated to a minimum energy of 30 MeV/u by RF cavities. The extraction system of the SRing will allow cooled ion beams to be extracted to an external target for further ion manipulations or reaction experiments. The general ion optics design and technical requirements of SRing subsystems are presented and discussed in this paper.

  9. Monopole-antimonopole and vortex rings

    International Nuclear Information System (INIS)

    Teh, Rosy; Wong, Khai-Ming

    2005-01-01

    The SU(2) Yang-Mills-Higgs theory supports the existence of monopoles, antimonopoles, and vortex rings. In this paper, we would like to present new exact static antimonopole-monopole-antimonopole (A-M-A) configurations. The net magnetic charge of these configurations is always -1, while the net magnetic charge at the origin is always +1 for all positive integer values of the solution's parameter m. However, when m increases beyond 1, vortex rings appear coexisting with these AMA configurations. The number of vortex rings increases proportionally with the value of m. They are located in space where the Higgs field vanishes along rings. We also show that a single-point singularity in the Higgs field does not necessarily correspond to a structureless 1-monopole at the origin but to a zero-size monopole-antimonopole-monopole (MAM) structure when the solution's parameter m is odd. This monopole is the Wu-Yang-type monopole and it possesses the Dirac string potential in the Abelian gauge. These exact solutions are a different kind of Bogomol'nyi-Prasad-Sommerfield (BPS) solutions as they satisfy the first-order Bogomol'nyi equation but possess infinite energy due to a point singularity at the origin of the coordinate axes. They are all axially symmetrical about the z-axis

  10. Access of energetic particles to storm time ring current through enhanced radial diffusion

    International Nuclear Information System (INIS)

    Lyons, L.R.; Schulz, M.

    1989-01-01

    Magnetic storms are distinguishable from other periods of geomagnetic activity by the injection of trapped electrons and ions to the 2 approx-lt L approx-lt 4 region. It has been proposed previously that this injection results from an inward displacement of the preexisting trapped-particle population by enhanced storm time electric fields. However, high-energy (approx-gt 40 keV) ring-current particles have drift periods that are typically shorter than the time of the main-phase development, and so the direct radial transport of these particles is restricted. The authors propose here that the transport of approx-gt 40 keV particles into the storm time ring current can result from enhanced stochastic radial transport driven by fluctuating electric fields during a storm's main phase. They estimate the effects of such electric fields by applying radial-diffusion theory, assuming a preexisting trapped-particle population as the initial conditions, and they demonstrate the feasibility of explaining observed flux increases of approx-gt 40-keV particles at L approx-lt 4 by enhanced radial diffusion. It is necessary that new particles be injected near the outer boundary of the trapping region so as to maintain the fluxes there as an outer boundary condition, and they estimate that the approx-gt 40-keV portion of the storm time ring current at L ∼ 3 consists of about 50% preexisting and about 50% new particles. They thus find that formation of the storm time ring current may be explainable via a combination of direct radial transport at energies approx-lt 40 keV and diffusive radial transport at higher energies

  11. A new storage-ring light source

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alex [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-06-01

    A recently proposed technique in storage ring accelerators is applied to provide potential high-power sources of photon radiation. The technique is based on the steady-state microbunching (SSMB) mechanism. As examples of this application, one may consider a high-power DUV photon source for research in atomic and molecular physics or a high-power EUV radiation source for industrial lithography. A less challenging proof-of-principle test to produce IR radiation using an existing storage ring is also considered.

  12. The Joint NASA/Goddard-University of Maryland Research Program in Charged Particle and High Energy Photon Detector Technology

    Science.gov (United States)

    Ipavich, F. M.

    1990-01-01

    The Univ. of Maryland portion investigated the following areas. The Space Physics Group performed studies of data from the AMPTE/CCE spacecraft CHEM experiment and found that the ratio of solar wind to photospheric abundances decreased rather smoothly with the first ionization potential (FIP) of the ion with the low FIP ion being about a factor of two overabundant. Carbon and hydrogen fit this trend particularly well. Several occurrences were analyzed of field aligned beams observed when CCE was upstream of the Earth's bow shock. Also using CHEM data, ring current intensity and composition changes during the main and recovery phases of the great geomagnetic storm that occurred in February 1986 was examined in detail. Still using CHEM data, ring current characteristics were examined in a survey of 20 magnetic storms ranging in size from -50 nT to -312 nT. A study was done of energetic ion anisotropy characteristics in the Earth's magnetosheath region using data from the UMD/MPE experiment on ISEE-1. The properties were analyzed of approx. 30 to 130 keV/e protons and alpha particles upstream of six quasi-parallel interplanetary shocks that passed by the ISEE-3 spacecraft during 1978 to 1979. Work from NASA-Goddard include studies from the High Energy Cosmic Ray Group, Low Energy Cosmic Ray Group, Low Energy Gamma Ray Group, High Energy Astrophysics Theory Group, and the X ray Astronomy Group.

  13. 4-twist helix snake to maintain polarization in multi-GeV proton rings

    Science.gov (United States)

    Antoulinakis, F.; Chen, Y.; Dutton, A.; Rossi De La Fuente, E.; Haupert, S.; Ljungman, E. A.; Myers, P. D.; Thompson, J. K.; Tai, A.; Aidala, C. A.; Courant, E. D.; Krisch, A. D.; Leonova, M. A.; Lorenzon, W.; Raymond, R. S.; Sivers, D. W.; Wong, V. K.; Yang, T.; Derbenev, Y. S.; Morozov, V. S.; Kondratenko, A. M.

    2017-09-01

    Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven's 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab's 120 GeV /c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9 - 120 GeV /c range. We found that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. This snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.

  14. 4-twist helix snake to maintain polarization in multi-GeV proton rings

    International Nuclear Information System (INIS)

    Antoulinakis, F.; Chen, Y.; Dutton, A.; Rossi De La Fuente, E.; Haupert, S.

    2017-01-01

    Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven’s 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab’s 120 GeV/c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9–120 GeV/c range. We found that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. Here, this snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.

  15. High energy accelerator and colliding beam user group: Progress report, March 1, 1987-February 29, 1988

    International Nuclear Information System (INIS)

    1987-09-01

    Progress is reported on the OPAL experiment at LEP, including construction and assembly of the hadron calorimeter and development of OPAL software. Progress on the JADE experiment, which examines e + e - interactions at PETRA, and of the PLUTO collaboration are also discussed. Experiments at Fermilab are reported, including deep inelastic muon scattering at TeV II, the D0 experiment at TeV I, and hadron jet physics. Neutrino-electron elastic scattering and a search for point-sources of ultra-high energy cosmic rays are reported. Other activities discussed include polarization in electron storage rings, participation in studies for the SSC and LEP 200, neutron-antineutron oscillations, and the work of the electronics support group. High energy physics computer experience is also discussed. 158 refs

  16. Black rings

    International Nuclear Information System (INIS)

    Emparan, Roberto; Reall, Harvey S

    2006-01-01

    A black ring is a five-dimensional black hole with an event horizon of topology S 1 x S 2 . We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)

  17. Future Synchrotron Light Sources Based on Ultimate Storage Rings

    International Nuclear Information System (INIS)

    Cai, Yunhai

    2012-01-01

    The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend achromatic cell, we

  18. Future Synchrotron Light Sources Based on Ultimate Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai; /SLAC

    2012-04-09

    The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend

  19. Status of the MEIC ion collider ring design

    International Nuclear Information System (INIS)

    Morozov, Vasiliy; Derbenev, Yaroslav; Harwood, Leigh; Hutton, Andrew; Lin, Fanglei; Pilat, Fulvia; Zhang, Yuhong; Cai, Yunhai; Nosochkov, Y. M.; Sullivan, Michael; Wang, M.-H.; Wienands, Uli; Gerity, James; Mann, Thomas; McIntyre, Peter; Pogue, Nathaniel; Sattarov, Akhdiyor

    2015-09-01

    We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated super-conducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.

  20. Status of the MEIC ion collider ring design

    International Nuclear Information System (INIS)

    Morozov, V. S.; Derbenev, Ya. S.; Harwood, L.; Hutton, A.; Lin, F.; Pilat, F.; Zhang, Y.; Cai, Y.; Nosochkov, Y. M.; Sullivan, M.; Wang, M-H; Wienands, U.; Gerity, J.; Mann, T.; McIntyre, P.; Pogue, N. J.; Satttarov, A.

    2015-01-01

    We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated superconducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.

  1. Project of the compact superconducting storage ring Siberia-SM

    Energy Technology Data Exchange (ETDEWEB)

    Anashin, V V; Arbuzov, V S; Blinov, G A; Veshcherevich, V G; Vobly, P D; Gorniker, E I; Zinevich, N I; Zinin, E I; Zubkov, N I; Kiselev, V A; Kollerov, E P; Kulipanov, G N; Matveev, Yu G; Medvedko, A S; Mezentsev, N A; Morgunov, L G; Petrov, V M; Petrov, S P; Repkov, V V; Roenko, V A; Skrinsky, A N; Sukhanov, S V; Tokarev, Yu I; Trakhtenberg, E M [AN SSSR, Novosibirsk. Inst. Yadernoj Fiziki

    1989-10-10

    In the last decade researches dealing with the creation of technology for X-ray lithography and for appropriate production equipment have been performed in many countries. The basic aim of these works is to provide a mass production of inexpensive devices with submicron structures (0.7-0.1 {mu}m). Bringing X-ray lithographic technology into commercial practice necessitates to design and build a dedicated SR source for the electronic industry. The use of superconducting bending magnets with 40-70 kG field strength enables the storage ring circumference to be reduced by a factor of 2-5 and the injection energy by a factor of 3-4 as compared to the conventional designs of storage rings. In the present paper we consider a storage ring which was designed for a maximum energy of 600 MeV, with 60 kG field strength in its bending magnets and 10 m circumference. The critical SR wavelength is 8.6 A. The electrons are injected into the storage ring at 50-60 MeV and the maximum stored current is assumed to be equal to 0.3 A. (orig.).

  2. X-ray spectroscopy of highly-charged ions in a storage ring. Invited lecture

    International Nuclear Information System (INIS)

    Beyer, H.F.

    1994-11-01

    The purpose of the present lectures is to carry through the methods and procedures necessary for a meaningful spectroscopy of the heaviest few-electron ions in relation to present theories. Results achieved so far in accelerator-based X-ray experiments are highlighted with emphasis on recent developments on heavy-ion storage rings. Starting with a brief account of the basics of one-electron ions, the motivation for doing X-ray spectroscopy of the simplest atomic systems with a high nuclear charge is given. In section 2 X-ray instrumentation and techniques are discussed including the precautions necessary when dealing with fast-beam sources. Peculiarities of heavy-ion storage rings are investigated in section 3 with regard to their use for spectroscopy. In section 4 are discussed results obtained so far on the measurement of the Lamb shift in very heavy ions. Section 5 gives some perspectives for the near future. (orig.)

  3. Halo and space charge issues in the SNS Ring

    International Nuclear Information System (INIS)

    Fedotov, A.V.; Abell, D.T.; Beebe-Wang, J.; Lee, Y.Y.; Malitsky, N.; Wei, J.; Gluckstern, R.L.

    2000-01-01

    The latest designs for high-intensity proton rings require minimizing beam-induced radioactivation of the vacuum chamber. Although the tune depression in the ring is much smaller than in high-intensity linacs, space-charge contributions to halo formation and, hence, beam loss may be significant. This paper reviews our current understanding of halo formation issues for the Spallation Neutron Source (SNS) accumulator ring

  4. Halo and space charge issues in the SNS Ring

    Energy Technology Data Exchange (ETDEWEB)

    Fedotov, A.V.; Abell, D.T.; Beebe-Wang, J.; Lee, Y.Y.; Malitsky, N.; Wei, J.; Gluckstern, R.L.

    2000-06-30

    The latest designs for high-intensity proton rings require minimizing beam-induced radioactivation of the vacuum chamber. Although the tune depression in the ring is much smaller than in high-intensity linacs, space-charge contributions to halo formation and, hence, beam loss may be significant. This paper reviews our current understanding of halo formation issues for the Spallation Neutron Source (SNS) accumulator ring.

  5. Escape of high-energy oxygen ions through magnetopause reconnection under northward IMF

    Directory of Open Access Journals (Sweden)

    S. Kasahara

    2008-12-01

    Full Text Available During a storm recovery phase on 15 May 2005, the Geotail spacecraft repeatedly observed high-energy (>180 keV oxygen ions in the dayside magnetosheath near the equatorial plane. We focused on the time period from 11:20 UT to 13:00 UT, when Geotail observed the oxygen ions and the interplanetary magnetic field (IMF was constantly northward. The magnetic reconnection occurrence northward and duskward of Geotail is indicated by the Walén analysis and convective flows in the magnetopause boundary layer. Anisotropic pitch angle distributions of ions suggest that high-energy oxygen ions escaped from the northward of Geotail along the reconnected magnetic field lines. From the low-energy particle precipitation in the polar cap observed by DMSP, which is consistent with magnetic reconnection occurring between the magnetosheath field lines and the magnetospheric closed field lines, we conclude that these oxygen ions are of ring current origin. Our results thus suggest a new escape route of oxygen ions during northward IMF. In the present event, this escape mechanism is more dominant than the leakage via the finite Larmor radius effect across the dayside equatorial magnetopause.

  6. Status of the Cryogenic Storage Ring (CSR)

    Energy Technology Data Exchange (ETDEWEB)

    Menk, Sebastian; Becker, Arno; Berg, Felix; Blaum, Klaus; Fellenberger, Florian; Froese, Michael; Goullon, Johannes; Grieser, Manfred; Krantz, Claude; Lange, Michael; Laux, Felix; Repnow, Roland; Schornikov, Andrey; Hahn, Robert von; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik (MPIK), 69117 Heidelberg (Germany); Spruck, Kaija [Institut fuer Atom- und Molekuelphysik Justus-Liebig-Universitaet, 35392 Giessen (Germany)

    2012-07-01

    A novel cryogenic storage ring is currently under construction at the MPIK. By electrostatic ion optical elements, the 35 m circumference Cryogenic Storage Ring will be able to store ions at energies of up to 300 keV per charge unit without any mass limitations. The CSR consists of a cryogenic ({proportional_to}5 K) beam pipe surrounded by two radiation shields (40 and 80 K) in a large outer, thermal insulation vacuum. Extreme vacuum (density {proportional_to}10{sup 3} cm{sup -3}) will be achieved by 2 K cryopumping as demonstrated in a prototype ion beam trap. The ion optics was completely assembled within the precision cryogenic mounting and shielding structure of the first corner. There, cooldown tests to {proportional_to}40 K were performed which confirmed the required sub-millimeter accuracy of the specially designed electrode positioning under large temperature changes. The high-voltage connections to the cryogenic electrodes were installed and breakdown tests will be reported. Based on the test results the beam pipe, electrode mounting and shielding structures are under final construction for mounting during 2012.

  7. Design study on a high brilliance lattice of the PF storage ring

    International Nuclear Information System (INIS)

    Katoh, M.; Araki, A.; Kobayashi, Y.; Hori, Y.

    1994-01-01

    A high brilliance lattice of the PF storage ring is proposed. A small beam emittance of 27 nm-rad (about one fifth of the present value) can be achieved by doubling the number of the quadrupoles in the FODO cells. This emittance reduction will result in ten times brighter synchrotron light from the existing insertion devices. The problems incidental to the low emittance lattice, the small dynamic aperture and the short Touschek lifetime, will be discussed. (author)

  8. CHICSi - a compact ultra-high vacuum compatible detector system for nuclear reaction experiments at storage rings. II. Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Golubev, P.; Avdeichikov, V.; Carlen, L.; Jakobsson, B. E-mail: bo.jakobsson@kosufy.lu.se; Siwek, A.; Veldhuizen, E.J. van; Westerberg, L.; Whitlow, H.J

    2003-03-11

    We describe the detectors for identification of charged particles and fragments in CHICSi, a large solid angle multi-telescope system mounted inside an ultra-high vacuum (UHV), cluster-jet target chamber. CHICSi performs nuclear reaction experiments at storage rings. The telescopes consist of a first very thin, 10-14 {mu}m Si detector, a second 300 {mu}m (or possibly 500 {mu}m) ion implanted Si detector supplemented by a 6 mm GSO(Ce) scintillator read out by a photodiode (PD) or by a third 300 {mu}m Si detector. The telescopes provide full charge separation up to Z=17 and mass resolution up to A=9 in the energy range 0.7-60A MeV. The thin p-i-n diode detector, etched out from a 280 {mu}m Si wafer, and the GSO/PD detector, both exclusively developed for CHICSi, provide an energy resolution {<=}8%, while the standard 300 {mu}m detectors have {<=}2% energy resolution. Radiation stability of the Si detectors is confirmed up to an integrated flux of 10{sup 10} alpha particles. The GSO detector has 70% light collection efficiency with the optical coupling to the PD a simple open, 0.2 mm, gap. A new method, developed to perform absolute energy calibration for the GSO/PD detector is presented.

  9. CHICSi - a compact ultra-high vacuum compatible detector system for nuclear reaction experiments at storage rings. II. Detectors

    International Nuclear Information System (INIS)

    Golubev, P.; Avdeichikov, V.; Carlen, L.; Jakobsson, B.; Siwek, A.; Veldhuizen, E.J. van; Westerberg, L.; Whitlow, H.J.

    2003-01-01

    We describe the detectors for identification of charged particles and fragments in CHICSi, a large solid angle multi-telescope system mounted inside an ultra-high vacuum (UHV), cluster-jet target chamber. CHICSi performs nuclear reaction experiments at storage rings. The telescopes consist of a first very thin, 10-14 μm Si detector, a second 300 μm (or possibly 500 μm) ion implanted Si detector supplemented by a 6 mm GSO(Ce) scintillator read out by a photodiode (PD) or by a third 300 μm Si detector. The telescopes provide full charge separation up to Z=17 and mass resolution up to A=9 in the energy range 0.7-60A MeV. The thin p-i-n diode detector, etched out from a 280 μm Si wafer, and the GSO/PD detector, both exclusively developed for CHICSi, provide an energy resolution ≤8%, while the standard 300 μm detectors have ≤2% energy resolution. Radiation stability of the Si detectors is confirmed up to an integrated flux of 10 10 alpha particles. The GSO detector has 70% light collection efficiency with the optical coupling to the PD a simple open, 0.2 mm, gap. A new method, developed to perform absolute energy calibration for the GSO/PD detector is presented

  10. Charge Exchange Contribution to the Decay of the Ring Current, Measured by Energetic Neutral Atoms (ENAs)

    Science.gov (United States)

    Jorgensen, A. M.; Henderson, M. G.; Roelof, E. C.; Reeves, G. D.; Spence, H. E.

    2001-01-01

    In this paper we calculate the contribution of charge exchange to the decay of the ring current. Past works have suggested that charge exchange of ring current protons is primarily responsible for the decay of the ring current during the late recovery phase, but there is still much debate about the fast decay of the early recovery phase. We use energetic neutral atom (ENA) measurements from Polar to calculate the total ENA energy escape. To get the total ENA escape we apply a forward modeling technique, and to estimate the total ring current energy escape we use the Dessler-Parker-Sckopke relationship. We find that during the late recovery phase of the March 10, 1998 storm ENAs with energies greater than 17.5 keV can account for 75% of the estimated energy loss from the ring current. During the fast recovery the measured ENAs can only account for a small portion of the total energy loss. We also find that the lifetime of the trapped ions is significantly shorter during the fast recovery phase than during the late recovery phase, suggesting that different processes are operating during the two phases.

  11. Third-order particle-hole ring diagrams with contact-interactions and one-pion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, N. [Technische Universitaet Muenchen, Physik-Department T39, Garching (Germany)

    2017-05-15

    The third-order particle-hole ring diagrams are evaluated for a NN-contact interaction of the Skyrme type. The pertinent four-loop coefficients in the energy per particle anti E(k{sub f}) ∝ k{sub f}{sup 5+2n} are reduced to double integrals over cubic expressions in Euclidean polarization functions. Dimensional regularization of divergent integrals is performed by subtracting power divergences and the validity of this method is checked against the known analytical results at second order. The complete O(p{sup 2}) NN-contact interaction is obtained by adding two tensor terms and their third-order ring contributions are also calculated in detail. The third-order ring energy arising from long-range 1π-exchange is computed and it is found that direct and exchange contributions are all attractive. The very large size of the three-ring energy due to point-like 1π-exchange, anti E(k{sub f0}) ≅ -92 MeV at saturation density, is however in no way representative for that of realistic chiral NN-potentials. Moreover, the third-order (particle-particle and hole-hole) ladder diagrams are evaluated with the full O(p{sup 2}) contact interaction, and the simplest three-ring contributions to the isospin-asymmetry energy A(k{sub f}) ∝ k{sub f}{sup 5} are studied. (orig.)

  12. Acceptability of microbicidal vaginal rings and oral pre-exposure prophylaxis for HIV prevention among female sex workers in a high-prevalence US city.

    Science.gov (United States)

    Peitzmeier, Sarah M; Tomko, Catherine; Wingo, Erin; Sawyer, Anne; Sherman, Susan G; Glass, Nancy; Beyrer, Chris; Decker, Michele R

    2017-11-01

    Biomedical HIV prevention tools including oral pre-exposure prophylaxis (PrEP) and vaginal microbicidal rings hold unique value for high-risk women who may have limited capacity for condom negotiation, including the key populations of sex workers and drug users. Commercial sex is a PrEP indicator in CDC guidelines, yet little is known about female sex workers' (FSWs) knowledge of and attitudes toward PrEP or the recently developed monthly vaginal microbicide rings. We describe knowledge and attitudes toward PrEP and microbicide rings in a sample of 60 mostly drug-using FSWs in Baltimore, Maryland, a high HIV-prevalence US city. Just 33% had heard of PrEP, but 65% were interested in taking daily oral PrEP and 76% were interested in a microbicide vaginal ring; 87% were interested in at least one of the two methods. Results suggest method mix will be important as biomedical tools for HIV prophylaxis are implemented and scaled up in this population, as 12% were interested in PrEP but not vaginal rings, while 19% were interested in vaginal rings but not in PrEP. Self-efficacy for daily oral adherence was high (79%) and 78% were interested in using PrEP even if condoms were still necessary. Women who had experienced recent client-perpetrated violence were significantly more interested in PrEP (86% vs 53%, p = 0.009) and microbicidal rings (91% vs 65%, p = 0.028) than women who had not recently experienced violence. No differences were observed by demographics nor HIV risk behaviors, suggesting broad potential interest in daily PrEP and monthly-use vaginal microbicides in this high-risk population.

  13. Variations in Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    Science.gov (United States)

    Brooks, S. M.; Spilker, L. J.; Pilorz, S.; Edgington, S. G.; Déau, E.; Altobelli, N.

    2010-12-01

    Cassini's Composite Infrared Spectrometer has recorded over two million of spectra of Saturn's rings in the far infrared since arriving at Saturn in 2004. CIRS records far infrared radiation between 10 and 600 cm-1 ( 16.7 and 1000 μ {m} ) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn’s rings peaks in this wavelength range. Ring temperatures can be inferred from FP1 data. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and rapidly changing temperatures are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid particles can be expected to have higher thermal inertias. Ferrari et al. (2005) fit thermal inertia values of 5218 {Jm)-2 {K}-1 {s}-1/2 to their B ring data and 6412 {Jm)-2 {K}-1 {s}-1/2 to their C ring data. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The rings’ thermal budget is dominated by its absorption of solar radiation. As a result, ring particles abruptly cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  14. Charged particle spin flip in a storage ring with HF-electromagnetic field

    International Nuclear Information System (INIS)

    Polunin, A.A.; Shatupov, Yu.M.

    1982-01-01

    An experiment for revealing a possibility of adiabatic electron spin flip in the VEPP-2M storage ring is described. High frequency longitudinal magnetic field up to 100 Gs at the length of 40 cm and frequency of 7.95 MHz was produced by a spiral of 10 coils supplied from HF-generator with 5 kW power. The control system permitted to vary generator frequency within +-3x10 - 3 f range during 10 - 3 -10 s. Determination of beam polarization degree was exercised by detection of electron elastic scattering inside the bunch. A possibility of changing the polarization sign at preservation of other beam parameters (dimensions, currents, energy, etc.) is of interest in experiments with polarized particles in storage rings. Spin flip can be exercised by effect on the beam of high frequency electromagnetic field, resonance with spin precession frequency around the leading field of the storage ring. The polarized 5 mA beam was produced due to radiation polarization at which electron spins are alinged along the direction of the magnetic field. Processing of the experimental results revealed good correspondence to analytical dependence. The depolarization value at the spin flip did not exceed 10%

  15. Ring tests on high density polyethylene: Full investigation assisted by finite element modeling

    International Nuclear Information System (INIS)

    Laiarinandrasana, L.; Devilliers, C.; Oberti, S.; Gaudichet, E.; Fayolle, B.; Lucatelli, J.M.

    2011-01-01

    In order to characterize the mechanical behavior of HDPE pipes, the ASTM D 2290-04 standard recommends carrying out tensile tests on notched rings, cut out from the pipe. This very simple test is also utilized to investigate the aging effect of the pipe by determining the strain at failure. Comparison between full ring and notched ring mechanical responses are discussed. Constitutive modeling including strain rate effects was performed by finite element analysis. This allowed a better understanding of the stress state in the cross section perpendicular to the loading direction. Additionally, the influence of a thin layer of oxidized HDPE in the inner wall of the ring was studied in the light of the finite element results.

  16. A practical guide to modern high energy particle accelerators

    International Nuclear Information System (INIS)

    Holmes, S.D.

    1987-10-01

    The purpose of these lectures is to convey an understanding of how particle accelerators work and why they look the way they do. The approach taken is physically intuitive rather than mathematically rigorous. The emphasis is on the description of proton circular accelerators and colliders. Linear accelerators are mentioned only in passing as sources of protons for higher energy rings. Electron accelerators/storage rings and antiproton sources are discussed only by way of brief descriptions of the features which distinguish them from proton accelerators. The basics of how generic accelerators work are discussed, focusing on descriptions of what sets the overall scale, single particle dynamics and stability, and descriptions of the phase space of the particle beam, the information thus presented is then used to go through the exercise of designing a Superconducting Super Collider

  17. Vacuum system for the NIJI-III compact storage ring

    International Nuclear Information System (INIS)

    Miura, F.; Tsutsui, Y.; Takada, H.

    1990-01-01

    The NIJI-III is a compact storage ring measuring about 15 m in circumference with four superconducting bending magnets. It is under development as a synchrotron light source for X-ray lithography with a stored beam current of 200 mA at a stored beam current of 200 mA at a stored energy level of 615 MeV. The vacuum system is designed to attain a pressure of less than 1 x 10 -9 Torr at beam storage. The compact ring design makes it difficult to install a large number of pumps able to satisfy the required pumping speed. For the purpose of realizing a high pumping speed, a cryopump as a result of cooling the superconducting magnet duct wall to the liquid helium (LHe) temperature is adopted, as a result the total pumping speed to 2.8 x 10 4 l/s is obtained. (author)

  18. New injection scheme using a pulsed quadrupole magnet in electron storage rings

    Directory of Open Access Journals (Sweden)

    Kentaro Harada

    2007-12-01

    Full Text Available We demonstrated a new injection scheme using a single pulsed quadrupole magnet (PQM with no pulsed local bump at the Photon Factory Advanced Ring (PF-AR in High Energy Accelerator Research Organization (KEK. The scheme employs the basic property of a quadrupole magnet, that the field at the center is zero, and nonzero elsewhere. The amplitude of coherent betatron oscillation of the injected beam is effectively reduced by the PQM; then, the injected beam is captured into the ring without largely affecting the already stored beam. In order to investigate the performance of the scheme with a real beam, we built the PQM providing a higher field gradient over 3  T/m and a shorter pulse width of 2.4  μs, which is twice the revolution period of the PF-AR. After the field measurements confirmed the PQM specifications, we installed it into the ring. Then, we conducted the experiment using a real beam and consequently succeeded in storing the beam current of more than 60 mA at the PF-AR. This is the first successful beam injection using a single PQM in electron storage rings.

  19. Characteristics of high-purity Teflon vial for 14C measurement in old tree rings

    International Nuclear Information System (INIS)

    Sakurai, H.; Saswaki, Y.; Matsumoto, T.; Aoki, T.; Kato, W.; Gandou, T.; Gunji, S.; Tokanai, F.

    2003-01-01

    14 C concentration in single-year tree rings of an old cedar of ca. 2500 years ago is measured to investigate the 11-yr periodicity of solar activity. Our highly accurate 14 C measuring system is composed of a benzene synthesizer capable of producing a large quantity (10 g) of benzene and a Quantulus 1220 TM liquid scintillation counting system. The accuracy is less than 0.2% for measurements of 14 C concentration. The benzene sample is contained in a high-purity Teflon/copper-counting vial (20 ml) manufactured by Wallac Oy Company. We found a vial with an irregular copper cap for the measurements of 11 tree rings. The behavior of the vial with the irregular cap was investigated. The Teflon sheet inside the cap plays an important role in achieving stable measurement. The rate of volatilization of the benzene was less than 0.35 mg/day for vials with ordinary caps. This results in the volatilization rate of 0.003% for 10.5 g of benzene and hence guarantees measurement at an accuracy of 0.2% for 70 days

  20. Development of a CZT drift ring detector for X and γ ray spectroscopy

    Science.gov (United States)

    Alruhaili, A.; Sellin, P. J.; Lohstroh, A.; Boothman, V.; Veeramani, P.; Veale, M. C.; Sawhney, K. J. S.; Kachkanov, V.

    2015-04-01

    CdTe and CZT detectors are considered better choices for high energy γ and X-ray spectroscopy in comparison to Si and HPGe detectors due to their good quantum efficiency and room temperature operation. The performance limitations in CdTe and CZT detectors are mainly associated with poor hole transport and trapping phenomena. Among many techniques that can be used to eliminate the effect of the poor charge transport properties of holes in CdTe and CZT material, the drift ring technique shows promising results. In this work, the performance of a 2.3 mm thick CZT drift ring detector is investigated. Spatially resolved measurements were carried out with an X-ray microbeam (25 and 75 keV) at the Diamond Light Source synchrotron to study the response uniformity and extent of the active area. Higher energy photon irradiation was also carried out at up to 662 keV using different radioisotopes to complement the microbeam data. Different biasing schemes were investigated in terms of biasing the cathode rear electrode (bulk field) and the ring electrodes (lateral fields). The results show that increasing the bulk field with fixed-ratio ring biases and lateral fields with fixed bulk fields increase the active area of the device significantly, which contrasts with previous studies in CdTe, where only an increasing lateral field resulted in an improvement of device performance. This difference is attributed to the larger thickness of the CZT device reported here.

  1. Towards an Understanding of Radiative Factors on Planetary Rings: a Perspective from Cassini CIRS Observations at Saturn Equinox

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, L.; Edgington, S. G.; Déau, E.; Pilorz, S. H.

    2012-10-01

    Since arriving at Saturn in 2004, Cassini's Composite Infrared Spectrometer has recorded tens of millions of spectra of Saturn’s rings (personal communication, M. Segura). CIRS records far infrared radiation (16.7-1000 microns) at focal plane 1 (FP1). Thermal emission from Saturn’s rings peaks at FP1 wavelengths. CIRS spectra are well characterized as blackbody emission at an effective temperature Te, multiplied by a scalar factor related to ring emissivity (Spilker et al. [2005, 2006]). CIRS can therefore characterize the rings' temperature and study the thermal environment to which the ring particles are subject. We focus on CIRS data from the 2009 Saturnian equinox. As the Sun's disk crossed the ring plane, CIRS obtained several radial scans of the rings at a variety of phase angles, local hour angles and distances. With the Sun's rays striking the rings at an incidence angle of zero, solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. These observations present an apparent paradox. Equinox data show that the flux of thermal energy radiated by the rings is roughly equivalent to or even exceeds the energy incident upon them as prescribed by thermal models (Froidevaux [1981], Ferrari and Leyrat [2006], Morishima et al. [2009, 2010]). This apparent energy excess is largest in the C ring and Cassini Division. Conservation principles suggest that models underestimate heating of the rings, as it is clearly unphysical for the rings to radiate significantly more energy than is incident upon them. In this presentation, we will attempt to resolve this paradox and determine what this can teach us about Saturn's rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.

  2. A numerical study of the quantum oscillations in multiple dangling rings

    International Nuclear Information System (INIS)

    Gu, B.Y.; Basu, C.

    1994-12-01

    We present the quantum mechanical calculations on magnetoconductance of the quantum waveguide topology containing multiply connected dangling mesoscopic rings with the transfer matrix approach. The profiles of the conductance as functions of the Fermi wave number of electrons and of the magnetic flux depend on the number of rings as also on the geometric configuration of the system. The conductance spectrum of this system for disordered lengths in the ring circumferences, dangling links, ballistic leads connecting consecutive dangling rings and disordered magnetic flux is examined in details. We find that there exist two kinds of mini-bands, one originating from the eigenstates of the rings, i.e. the intrinsic mini-bands, and the extra mini-bands. Some of these extra minibands are associated with the dangling links connecting the rings to the main quantum wire, while others are from the standing wave modes associated with the ballistic leads connecting adjacent dangling rings. These different kinds of mini-bands have completely different properties and responds differently to the geometric parameter fluctuations. Unlike the system of potential scatterers, this system of geometric scatterers shows complete band formations at all energies even for finite number of scatterers present. There is a preferential decay of the energy states, depending upon the type of disorder introduced. By controlling the geometric parameters, the conductance band structure of such a model can be artificially tailored and thus may guide the design of better mesoscopic switching devices. (author). 19 refs, 7 figs

  3. Angular distribution of Pionization particles from experiments on CERN-storage rings

    CERN Document Server

    Jabs, A

    1972-01-01

    The angular distribution of secondary charged particles arising from high energy interaction in the CERN storage rings has been measured. The measurements near the centre-of-mass energies (20-50) GeV have been taken in the angle range of 20-90 degrees relative to the recoil axis. A complex formula is suggested to explain the variations described experimentally. Good agreement between the theoretical and experimental data is found. Simplifications are possible in the formula which allow the two-centre emission structure to be explained. It is shown that the angular dependence cannot be explained solely from rotary impulse behaviour. (9 refs).

  4. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  5. Primitivity and weak distributivity in near rings and matrix near rings

    International Nuclear Information System (INIS)

    Abbasi, S.J.

    1993-08-01

    This paper shows the structure of matrix near ring constructed over a weakly distributive and primative near ring. It is proved that a weakly distributive primitive near ring is a ring and the matrix near rings constructed over it is also a bag. (author). 14 refs

  6. On Radiative Factors in Planetary Rings: New Insight Derived from Cassini CIRS Observations at Saturn Equinox

    Science.gov (United States)

    Brooks, S. M.; Spilker, L. J.; Pilorz, S.; Edgington, S. G.; Deau, E.; Morishima, R.

    2012-12-01

    Since arriving at Saturn in 2004, Cassini's Composite Infrared Spectrometer has recorded tens of millions of spectra of Saturn's rings (personal communication, M. Segura). CIRS records far infrared radiation (16.7-1000 microns) at focal plane 1 (FP1). Thermal emission from Saturn's rings peaks at FP1 wavelengths. CIRS spectra are well characterized as blackbody emission at an effective temperature Te, multiplied by a scalar factor related to ring emissivity (Spilker et al. [2005, 2006]). CIRS can therefore characterize the rings' temperature and study the thermal environment to which the ring particles are subject. We focus on CIRS data from the 2009 Saturnian equinox. As the Sun's disk crossed the ring plane, CIRS obtained several radial scans of the rings at a variety of phase angles, local hour angles and distances. With the Sun's rays striking the rings at an incidence angle of zero, solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. These observations appear to present a paradox. Equinox data show that the flux of thermal energy radiated by the rings can even exceed the energy incident upon them as prescribed by thermal models, particularly in the C ring and Cassini Division (Ferrari and Leyrat [2006], Morishima et al. [2009, 2010]). Conservation principles suggest that such models underestimate heating of the rings in these cases, as it is clearly unphysical for the rings to radiate significantly more energy than is incident upon them. In this presentation, we will describe our efforts to resolve this paradox and determine what doing so can teach us about Saturn's rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.

  7. Microwave energy harvesting based on metamaterial absorbers with multi-layered square split rings for wireless communications

    Science.gov (United States)

    Karaaslan, Muharrem; Bağmancı, Mehmet; Ünal, Emin; Akgol, Oguzhan; Sabah, Cumali

    2017-06-01

    We propose the design of a multiband absorber based on multi-layered square split ring (MSSR) structure. The multi-layered metamaterial structure is designed to be used in the frequency bands such as WIMAX, WLAN and satellite communication region. The absorption levels of the proposed structure are higher than 90% for all resonance frequencies. In addition, the incident angle and polarization dependence of the multi-layered metamaterial absorber and harvester is also investigated and it is observed that the structure has polarization angle independent frequency response with good absorption characteristics in the entire working frequency band. The energy harvesting ratios of the structure is investigated especially for the resonance frequencies at which the maximum absorption occurs. The energy harvesting potential of the proposed MSSRs is as good as those of the structures given in the literature. Therefore, the suggested design having good absorption, polarization and angle independent characteristics with a wide bandwidth is a potential candidate for future energy harvesting applications in commonly used wireless communication bands, namely WIMAX, WLAN and satellite communication bands.

  8. Undulator sources at a 8 GeV storage ring

    International Nuclear Information System (INIS)

    Harami, Taikan.

    1989-06-01

    The use of undulators plays an important role as a high brilliance sources of synchrotron photon at a facility having an electron (or positron) storage ring. This paper describes the characteristics, tunability from gap variation and brilliance of synchrotron photon from undulators at a 8 GeV storage ring. The numerical studies show the following results. (1) Undulators for a 8 GeV storage ring can cover the first harmonic photon energy range from about 0.3 to 30 keV and the third harmonic photon from 0.85 to 70 keV. (2) The brilliance of undulator can be expected to be the order of 10 21 photons/(sec mm 2 mrad 2 0.1% band width mA), without size and angular spread in the electron beam (diffraction limit). (3) The peak brilliance has a broad maximum as a function of β function of the lattice and is shown to be practically independent on the β function. The peak brilliance is calculated to be the order of 10 16 photons/(sec mm 2 mrad 2 0.1% band width mA) at the electron beam emittance of 5 x 10 -9 m·rad (undulator length 2 m). (4) The nuclei of 57 Fe, 119 Sn and 238 U are expected to be the candidates for the Moessbauer scattering experiment using synchrotron photon from a 8 GeV storage ring. (author)

  9. Status and biology of ringed seals (Phoca hispida in Svalbard

    Directory of Open Access Journals (Sweden)

    Christian Lydersen

    1998-06-01

    water prior to weaning. They are capable of diving for up to 12min and dive to the bottom of the study areas (max. 89 m. Nursing females spend more than 80% of their time in the water. Maximum recorded dive duration for mothers was 21.2 min. In order to produce a weaned pup, the net energy expenditure for a ringed seal mother is 1,073 MJ. This energy value corresponds to the consumption of 185 kg of polar cod or 282 kg of P. libellula. The annual gross energy consumption for adult males and females is calculated to be 5,600 MJ and 7,300 MJ, respectively. The main predators of ringed seals in Svalbard are polar bears (Ursus maritimus and Arctic foxes (Alopex lagopus. In addition, both glaucous gulls (Larus hyperboreus and walruses (Odobenus rosmarus are documented as predators of ringed seals in this area. Heavy predation pressure is probably the main factor explaining why pups of this species start diving at such a young age, why they have access to so many breathing holes (8.7 on average and why they keep their white coat long after its thermoregulatory properties have vanished. Pollution levels in ringed seals from Svalbard are, generally speaking, similar to levels in other areas of the Arctic.

  10. Origin and dynamics of vortex rings in drop splashing.

    Science.gov (United States)

    Lee, Ji San; Park, Su Ji; Lee, Jun Ho; Weon, Byung Mook; Fezzaa, Kamel; Je, Jung Ho

    2015-09-04

    A vortex is a flow phenomenon that is very commonly observed in nature. More than a century, a vortex ring that forms during drop splashing has caught the attention of many scientists due to its importance in understanding fluid mixing and mass transport processes. However, the origin of the vortices and their dynamics remain unclear, mostly due to the lack of appropriate visualization methods. Here, with ultrafast X-ray phase-contrast imaging, we show that the formation of vortex rings originates from the energy transfer by capillary waves generated at the moment of the drop impact. Interestingly, we find a row of vortex rings along the drop wall, as demonstrated by a phase diagram established here, with different power-law dependencies of the angular velocities on the Reynolds number. These results provide important insight that allows understanding and modelling any type of vortex rings in nature, beyond just vortex rings during drop splashing.

  11. Sphagnum moss disperses spores with vortex rings.

    Science.gov (United States)

    Whitaker, Dwight L; Edwards, Joan

    2010-07-23

    Sphagnum spores, which have low terminal velocities, are carried by turbulent wind currents to establish colonies many kilometers away. However, spores that are easily kept aloft are also rapidly decelerated in still air; thus, dispersal range depends strongly on release height. Vascular plants grow tall to lift spores into sufficient wind currents for dispersal, but nonvascular plants such as Sphagnum cannot grow sufficiently high. High-speed videos show that exploding capsules of Sphagnum generate vortex rings to efficiently carry spores high enough to be dispersed by turbulent air currents. Spores launched ballistically at similar speeds through still air would travel a few millimeters and not easily reach turbulent air. Vortex rings are used by animals; here, we report vortex rings generated by plants.

  12. Orbital dynamics in a storage ring with electrostatic bending

    International Nuclear Information System (INIS)

    Mane, S.R.

    2008-01-01

    A storage ring where electrostatic fields contribute to the bending and focusing of the orbital motion has some novel features because, unlike a magnetostatic field, an electrostatic field can change the kinetic energy of the particles. I present analytical formulas to calculate the linear focusing gradient, dispersion, momentum compaction and natural chromaticity for a storage ring with a radial electrostatic field. I solve the formulas explicitly for a weak focusing model.

  13. Seasonal variation of the radial brightness contrast of Saturn's rings viewed in mid-infrared by Subaru/COMICS

    Science.gov (United States)

    Fujiwara, Hideaki; Morishima, Ryuji; Fujiyoshi, Takuya; Yamashita, Takuya

    2017-03-01

    Aims: This paper investigates the mid-infrared (MIR) characteristics of Saturn's rings. Methods: We collected and analyzed MIR high spatial resolution images of Saturn's rings obtained in January 2008 and April 2005 with the COoled Mid-Infrared Camera and Spectrometer (COMICS) mounted on the Subaru Telescope, and investigated the spatial variation in the surface brightness of the rings in multiple bands in the MIR. We also composed the spectral energy distributions (SEDs) of the C, B, and A rings and the Cassini Division, and estimated the temperatures of the rings from the SEDs assuming the optical depths. Results: We found that the C ring and the Cassini Division were warmer than the B and A rings in 2008, which could be accounted for by their lower albedos, lower optical depths, and smaller self-shadowing effect. We also fonud that the C ring and the Cassini Division were considerably brighter than the B and A rings in the MIR in 2008 and the radial contrast of the ring brightness is the inverse of that in 2005, which is interpreted as a result of a seasonal effect with changing elevations of the Sun and observer above the ring plane. The reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A29

  14. Researches on the Piston Ring

    Science.gov (United States)

    Ehihara, Keikiti

    1944-01-01

    In internal combustion engines, steam engines, air compressors, and so forth, the piston ring plays an important role. Especially, the recent development of Diesel engines which require a high compression pressure for their working, makes, nowadays, the packing action of the piston ring far more important than ever. Though a number of papers have been published in regard to researches on the problem of the piston ring, none has yet dealt with an exact measurement of pressure exerted on the cylinder wall at any given point of the ring. The only paper that can be traced on this subject so far is Mr. Nakagawa's report on the determination of the relative distribution of pressure on the cylinder wall, but the measuring method adopted therein appears to need further consideration. No exact idea has yet been obtained as to how the obturation of gas between the piston and cylinder, the frictional resistance of the piston, and the wear of the cylinder wall are affected by the intensity and the distribution of the radial pressure of the piston ring. Consequently, the author has endeavored, by employing an apparatus of his own invention, to get an exact determination of the pressure distribution of the piston ring. By means of a newly devised ring tester, to which piezoelectricity of quartz was applied, the distribution of the radial pressure of many sample rings on the market was accurately determined. Since many famous piston rings show very irregular pressure distribution, the author investigated and achieved a manufacturing process of the piston ring which will exert uniform pressure on the cylinder wall. Temperature effects on the configuration and on the mean spring power have also been studied. Further, the tests were performed to ascertain how the gas tightness of the piston ring may be affected by the number or spring power. The researches as to the frictional resistance between the piston ring and the cylinder wall were carried out, too. The procedure of study, and

  15. Large superconducting detector magnets with ultra thin coils for use in high energy accelerators and storage rings

    International Nuclear Information System (INIS)

    Green, M.A.

    1977-08-01

    The development of a new class of large superconducting solenoid magnets is described. High energy physics on colliding beam machines sometimes require the use of thin coil solenoid magnets. The development of these magnets has proceeded with the substitution of light materials for heavy materials and by increasing the current density in the coils. The Lawrence Berkeley Laboratory has developed a radical approach to the problem by having the coil operate at very high current densities. This approach and its implications are described in detail

  16. Interaction of ring dark solitons with ring impurities in Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Xue Jukui

    2005-01-01

    The interaction of ring dark solitons/vortexes with the ring-shaped repulsive and attractive impurities in two-dimensional Bose-Einstein condensates is investigated numerically. Very rich interaction phenomena are obtained, i.e., not only the interaction between the ring soliton and the impurity, but also the interaction between vortexes and the impurity. The interaction characters, i.e., snaking of ring soliton, quasitrapping or reflection of ring soliton and vortexes by the impurity, strongly depend on initial ring soliton velocity, impurity strength, initial position of ring soliton and impurity. The numerical results also reveal that ring dark solitons/vortexes can be trapped and dragged by an adiabatically moving attractive ring impurity

  17. Effect of an internal target on the beam behaviour in a storage ring

    International Nuclear Information System (INIS)

    Diehl, N.

    1988-04-01

    For the study of the effects of an internal target on the beam behaviour in a storage ring a Monte Carlo simulation program was developed. Special importance was attached to the ranges of validity of the used models. The dominating effects are the Coulomb scattering of the projectiles on the target nuclei, which lead to an angular dispersion, and the collisions of the projectiles on the electrons of the target atoms which cause an energy loss. The target effects are regarded in the simulation program. The simulation calculations for the storage ring COSY give cause for the hope that experiments with internal targets because of high luminosity represent an interesting alternative in spite of thin targets. (orig./HSI) [de

  18. The Hi-Ring architecture for datacentre networks

    DEFF Research Database (Denmark)

    Galili, Michael; Kamchevska, Valerija; Ding, Yunhong

    2016-01-01

    This paper summarizes recent work on a hierarchical ring-based network architecture (Hi-Ring) for datacentre and short-range applications. The architecture allows leveraging benefits of optical switching technologies while maintaining a high level of connection granularity. We discuss results...

  19. Reactive probing of macroscopically quantum mechanical SQUID rings

    International Nuclear Information System (INIS)

    Prance, R.J.; Clark, T.D.; Whiteman, R.; Diggins, J.; Ralph, J.F.; Prance, H.; Spiller, T.P.; Widom, A.; Srivastava, Y.

    1994-01-01

    In this paper we demonstrate that the energy level structure of ultra small capacitance SQUID rings can be probed adiabatically at radio frequency using both dynamical and quasistatic reactive techniques. ((orig.))

  20. Dielectronic recombination experiments with tungsten ions at the test storage ring and development of a single-particle detector at the cryogenic storage ring

    International Nuclear Information System (INIS)

    Spruck, Kaija

    2015-05-01

    This work is about electron-ion collision experiments at the ion storage rings of the Max Planck Institute for Nuclear Physics in Heidelberg. Absolute recombination rate coefficients of highly-charged tungsten ions featuring an open 4-f-shell structure have been measured at the heavy-ion storage ring TSR. The resulting plasma rate coefficients have been used to probe the significance of newly developed theoretical approaches. Plasma rate coefficients of highly-charged tungsten ions are in particular interesting for the development of plasma models for nuclear fusion reactors, since tungsten is a foreseeable impurity in the fusion plasma. In the relevant temperature range, the experimental results exceed the theoretical data used so far by up to a factor of 10, showing the need for more reliable theoretical calculations. Furthermore, based on the design of the detectors which have been used in the experiments at TSR, a movable single-particle detector for electron-ion recombination studies at the cryogenic storage ring CSR has been developed and installed within the scope of this work. The device has been designed specifically to meet the requirements of the CSR regarding low ion energies and cryogenic ambient temperature conditions. In a series of experiments, the detector was carefully characterised and successfully tested for its compatibility with these requirements. The detector was part of the infrastructure used for the room-temperature commissioning of CSR (2014) and is currently operated as a single-particle counter during the first cryogenic operation of CSR in 2015.

  1. Dielectronic recombination experiments with tungsten ions at the test storage ring and development of a single-particle detector at the cryogenic storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Spruck, Kaija

    2015-05-15

    This work is about electron-ion collision experiments at the ion storage rings of the Max Planck Institute for Nuclear Physics in Heidelberg. Absolute recombination rate coefficients of highly-charged tungsten ions featuring an open 4-f-shell structure have been measured at the heavy-ion storage ring TSR. The resulting plasma rate coefficients have been used to probe the significance of newly developed theoretical approaches. Plasma rate coefficients of highly-charged tungsten ions are in particular interesting for the development of plasma models for nuclear fusion reactors, since tungsten is a foreseeable impurity in the fusion plasma. In the relevant temperature range, the experimental results exceed the theoretical data used so far by up to a factor of 10, showing the need for more reliable theoretical calculations. Furthermore, based on the design of the detectors which have been used in the experiments at TSR, a movable single-particle detector for electron-ion recombination studies at the cryogenic storage ring CSR has been developed and installed within the scope of this work. The device has been designed specifically to meet the requirements of the CSR regarding low ion energies and cryogenic ambient temperature conditions. In a series of experiments, the detector was carefully characterised and successfully tested for its compatibility with these requirements. The detector was part of the infrastructure used for the room-temperature commissioning of CSR (2014) and is currently operated as a single-particle counter during the first cryogenic operation of CSR in 2015.

  2. Shielding considerations for an electron linear accelerator complex for high energy physics and photonics research

    International Nuclear Information System (INIS)

    Holmes, J.A.; Huntzinger, C.J.

    1987-01-01

    Radiation shielding considerations for a major high-energy physics and photonics research complex which comprise a 50 MeV electron linear accelerator injector, a 1.0 GeV electron linear accelerator and a 1.3 GeV storage ring are discussed. The facilities will be unique because of the close proximity of personnel to the accelerator beam lines, the need to adapt existing facilities and shielding materials and the application of strict ALARA dose guidelines while providing maximum access and flexibility during a phased construction program

  3. Molecular spectrum of laterally coupled quantum rings under intense terahertz radiation.

    Science.gov (United States)

    Baghramyan, Henrikh M; Barseghyan, Manuk G; Laroze, David

    2017-09-05

    We study the influence of intense THz laser radiation and electric field on molecular states of laterally coupled quantum rings. Laser radiation shows the capability to dissociate quantum ring molecule and add 2-fold degeneracy to the molecular states at the fixed value of the overlapping size between rings. It is shown that coupled to decoupled molecular states phase transition points form almost a straight line with a slope equal to two. In addition, the electric field direction dependent energy spectrum shows unexpected oscillations, demonstrating strong coupling between molecular states. Besides, intraband absorption is considered, showing both blue and redshifts in its spectrum. The obtained results can be useful for the controlling of degeneracy of the discrete energy spectrum of nanoscale structures and in the tunneling effects therein.

  4. Excitonic energy transfer in light-harvesting complexes in purple bacteria

    International Nuclear Information System (INIS)

    Ye Jun; Sun Kewei; Zhao Yang; Lee, Chee Kong; Yu Yunjin; Cao Jianshu

    2012-01-01

    Two distinct approaches, the Frenkel-Dirac time-dependent variation and the Haken-Strobl model, are adopted to study energy transfer dynamics in single-ring and double-ring light-harvesting (LH) systems in purple bacteria. It is found that the inclusion of long-range dipolar interactions in the two methods results in significant increase in intra- or inter-ring exciton transfer efficiency. The dependence of exciton transfer efficiency on trapping positions on single rings of LH2 (B850) and LH1 is similar to that in toy models with nearest-neighbor coupling only. However, owing to the symmetry breaking caused by the dimerization of BChls and dipolar couplings, such dependence has been largely suppressed. In the studies of coupled-ring systems, both methods reveal an interesting role of dipolar interactions in increasing energy transfer efficiency by introducing multiple intra/inter-ring transfer paths. Importantly, the time scale (4 ps) of inter-ring exciton transfer obtained from polaron dynamics is in good agreement with previous studies. In a double-ring LH2 system, non-nearest neighbor interactions can induce symmetry breaking, which leads to global and local minima of the average trapping time in the presence of a non-zero dephasing rate, suggesting that environment dephasing helps preserve quantum coherent energy transfer when the perfect circular symmetry in the hypothetic system is broken. This study reveals that dipolar coupling between chromophores may play an important role in the high energy transfer efficiency in the LH systems of purple bacteria and many other natural photosynthetic systems.

  5. Excitonic energy transfer in light-harvesting complexes in purple bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ye Jun; Sun Kewei; Zhao Yang; Lee, Chee Kong [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Yu Yunjin [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); College of Physics Science and Technology, Shenzhen University, Guangdong 518060 (China); Cao Jianshu [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2012-06-28

    Two distinct approaches, the Frenkel-Dirac time-dependent variation and the Haken-Strobl model, are adopted to study energy transfer dynamics in single-ring and double-ring light-harvesting (LH) systems in purple bacteria. It is found that the inclusion of long-range dipolar interactions in the two methods results in significant increase in intra- or inter-ring exciton transfer efficiency. The dependence of exciton transfer efficiency on trapping positions on single rings of LH2 (B850) and LH1 is similar to that in toy models with nearest-neighbor coupling only. However, owing to the symmetry breaking caused by the dimerization of BChls and dipolar couplings, such dependence has been largely suppressed. In the studies of coupled-ring systems, both methods reveal an interesting role of dipolar interactions in increasing energy transfer efficiency by introducing multiple intra/inter-ring transfer paths. Importantly, the time scale (4 ps) of inter-ring exciton transfer obtained from polaron dynamics is in good agreement with previous studies. In a double-ring LH2 system, non-nearest neighbor interactions can induce symmetry breaking, which leads to global and local minima of the average trapping time in the presence of a non-zero dephasing rate, suggesting that environment dephasing helps preserve quantum coherent energy transfer when the perfect circular symmetry in the hypothetic system is broken. This study reveals that dipolar coupling between chromophores may play an important role in the high energy transfer efficiency in the LH systems of purple bacteria and many other natural photosynthetic systems.

  6. Large high current density superconducting solenoids for use in high energy physics experiments

    International Nuclear Information System (INIS)

    Green, M.A.; Eberhard, P.H.; Taylor, J.D.

    1976-05-01

    Very often the study of high energy physics in colliding beam storage-rings requires a large magnetic field volume in order to detect and analyze charged particles which are created from the collision of two particle beams. Large superconducting solenoids which are greater than 1 meter in diameter are required for this kind of physics. In many cases, interesting physics can be done outside the magnet coil, and this often requires that the amount of material in the magnet coil be minimized. As a result, these solenoids should have high current density (up to 10 9 A m -2 ) superconducting windings. The methods commonly used to stabilize large superconducting magnets cannot be employed because of this need to minimize the amount of material in the coils. A description is given of the Lawrence Berkeley Laboratory program for building and testing prototype solenoid magnets which are designed to operate at coil current densities in excess of 10 9 A m -2 with magnetic stored energies which are as high as 1.5 Megajoules per meter of solenoid length. The coils use intrinsically stable multifilament Nb--Ti superconductors. Control of the magnetic field quench is achieved by using a low resistance aluminum bore tube which is inductively coupled to the coil. The inner cryostat is replaced by a tubular cooling system which carries two phase liquid helium. The magnet coil, the cooling tubes, and aluminum bore tube are cast in epoxy to form a single unified magnet and cryogenic system which is about 2 centimeters thick. The results of the magnet coil tests are discussed

  7. The Rings of Saturn

    Science.gov (United States)

    Cuzzi, J. N.; Filacchione, G.; Marouf, E. A.

    2018-03-01

    One could become an expert on Saturn's iconic rings pretty easily in the early 1970s, as very little was known about them beyond the distinction between the A, B, and C rings, and the Cassini Division or "gap" between rings A and B (Alexander, 1962; Bobrov, 1970). Water ice was discovered spectroscopically on the ring particle surfaces, and radar and microwave emission observations proved that the particles must be centimeters to meters in size, consisting primarily, not just superficially, of water ice (Pollack, 1975). While a 2:1 orbital resonance with Mimas had long been suspected of having something to do with the Cassini Division, computers of the time were unable to model the subtle dynamical effects that we now know to dominate ring structure. This innocent state of affairs was exploded by the Voyager 1 and 2 encounters in 1980 and 1981. Spectacular images revealed filigree structure and odd regional color variations, and exquisitely detailed radial profiles of fluctuating particle abundance were obtained from the first stellar and radio occultations, having resolution almost at the scale of single particles. Voyager-era understanding was reviewed by Cuzzi et al. (1984) and Esposito et al. (1984). While the Voyager data kept ring scientists busy for decades, planning which led to the monumentally successful NASA-ESA-ASI Cassini mission, which arrived in 2004, had been under way even before Voyager got to Saturn. A review of pre-Cassini knowledge of Saturn's Rings can be found in Orton et al. (2009). This chapter will build on recent topical and process-specific reviews that treat the gamut of ring phenomena and its underlying physics in considerable detail (Colwell et al., 2009; Cuzzi et al., 2009; Horányi et al., 2009; Schmidt et al., 2009; Esposito, 2010; Tiscareno, 2013b; Esposito, 2014). We will follow and extend the general organization of Cuzzi et al. (2010), the most recent general discussion of Saturn's rings. For brevity and the benefit of the

  8. An Updated Review of Dendrochronological Investigations in Mexico, a Megadiverse Country with a High Potential for Tree-Ring Sciences

    Directory of Open Access Journals (Sweden)

    Andrea C. Acosta-Hernández

    2017-05-01

    Full Text Available Dendrochronology is a very useful science to reconstruct the long-term responses of trees and other woody plants forming annual rings in response to their environment. The present review considered Mexico, a megadiverse country with a high potential for tree-ring sciences given its high climatic and environmental variability. We reviewed papers considering Mexican tree species that were published from 2001 to 2016. Most of these studies examined tree species from temperate forests, mainly in the pine and fir species. The review included 31 tree species. The most intensively sampled family and species were the Pinaceae and Douglas fir (Pseudotsuga menziessi (Mirb. Franco, respectively. Some threatened tree species were also studied. Dendrochronological investigations were mainly conducted in northern and central Mexico, with Durango being the most sampled state. The reviewed studies were mostly developed for hydroclimatic reconstructions, which were mainly based on the tree-ring width as a proxy for the climate. Tree-ring studies were carried out in both national and foreign institutions. Our review identified relevant research gaps for dendrochronologists such as: (i biomes which are still scarcely studied (e.g., tropical dry forests and (ii approaches still rarely applied to Mexican forests as dendroecology.

  9. Ring cavity surface emitting semiconductor lasers

    International Nuclear Information System (INIS)

    Mujagic, E.

    2010-01-01

    Quantum cascade lasers (QCLs) are electrically driven semiconductor lasers, which have undergone a steady improvement since the first demonstration in 1994. These are now well established as reliable sources of coherent light in the mid-infrared (MIR) and terahertz (THz)range of the electromagnetic spectrum (3-300 μm). The rapid progress of this type of lasers is based on a high degree of freedom in tailoring the emission wavelength within a large variety of semiconductor heterostructure designs and materials. These properties have attracted the attention of various applications such as gas analysis, chemical sensing, spectral imaging and free-space telecommunication. In order to improve the selectivity, sensitivity and efficiency of today's sensor systems, high optical power, continuous wave and room temperature performance, single-mode operation and low divergence optical beams, are highly desirable qualities of a compact laser source in this field of research. Since all of these features cannot be provided by a conventional edge-emitting device at the same time, research has put focus on the development of surface emitting devices. Nowadays, the vertical cavity surface emitting lasers (VCSELs) are the most prominent representative for this type of light emitters. With its capability of producing narrow circular beams, the feasibility of two-dimensional arrays and on-wafer testing, such a coherent light source results in a reduction of the fabrication effort and production costs. Since the radiation in QCLs is strictly polarized normal to the epitaxial layer plane, fabrication of VCSELs based on QC structures is not viable. The subject of this work is the design and realization of 'ring cavity surface emitting lasers' (ring-CSELs). This type of lasers employs a circular ring cavity and a resonant distributed feedback (DFB) surface grating. Ring-CSELs were fabricated on the basis of MIR and THz QC structures, which cover a wavelength range from 4 μm to 93

  10. Pulse Power Modulator development for the CLIC Damping Ring Kickers

    CERN Document Server

    Holma, Janne

    2012-01-01

    The Compact Linear Collider (CLIC) study is exploring the scheme for an electron-positron collider with high luminosity (10-34 – 10-35 cm-2s-1) and a nominal centre-of-mass energy of 3 TeV: CLIC would complement LHC physics in the multi-TeV range. The CLIC design relies on Pre-Damping Rings (PDR) and Damping Rings (DR) to achieve the very low emittance, through synchrotron radiation, needed for the luminosity requirements of CLIC. To limit the beam emittance blow-up due to oscillations, the pulse power modulators for the DR kickers must provide extremely flat, high-voltage pulses: the 2 GHz specification called for a 160 ns duration flat-top of 12.5 kV, 250 A, with a combined ripple and droop of not more than ±0.02 %. In order to meet these demanding specifications, a combination of broadband impedance matching, optimized electrical circuit layout and advanced control techniques is required. A solid-state modulator, the inductive adder, is the most promising approach to meeting the demanding specifications...

  11. Highly Efficient Spin-Current Operation in a Cu Nano-Ring

    Science.gov (United States)

    Murphy, Benedict A.; Vick, Andrew J.; Samiepour, Marjan; Hirohata, Atsufumi

    2016-11-01

    An all-metal lateral spin-valve structure has been fabricated with a medial Copper nano-ring to split the diffusive spin-current path. We have demonstrated significant modulation of the non-local signal by the application of a magnetic field gradient across the nano-ring, which is up to 30% more efficient than the conventional Hanle configuration at room temperature. This was achieved by passing a dc current through a current-carrying bar to provide a locally induced Ampère field. We have shown that in this manner a lateral spin-valve gains an additional functionality in the form of three-terminal gate operation for future spintronic logic.

  12. First year of data taking at high energy for MoEDAL

    CERN Multimedia

    CERN Bulletin

    2016-01-01

    MoEDAL - the LHC experiment designed to search for highly ionising avatars of new physics, such as magnetic monopoles or massive pseudo-stable charged particles - has collected data from p-p and Pb-Pb collisions at high energy. A unique feature of the experiment is its membership, which includes a high school.   Visualisation of the MoEDAL array in the LHCb cavern. (Photo: MoEDAL Collaboration) MoEDAL’s physics programme is investigating more than 34 scenarios that could yield potentially revolutionary insights into such fundamental questions as: are there extra dimensions or new symmetries? Where does the mechanism for the generation of mass originate from? Does magnetic charge exist? What is the nature of dark matter? How did the Big Bang develop? MoEDAL employs a number of unconventional methodologies, specially tuned to the prospect of discovery physics. The largely passive MoEDAL detector, deployed at Point 8 on the LHC ring, works in two ways. First, it acts like...

  13. CESAR, 2 MeV electron storage ring; general view.

    CERN Multimedia

    CERN PhotoLab

    1964-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  14. Beam Optics for FCC-ee Collider Ring

    CERN Document Server

    Oide, Katsunobu; Aumon, S; Benedikt, M; Blondel, A; Bogomyagkov, A V; Boscolo, M; Burkhardt, H; Cai, Y; Doblhammer, A; Haerer, B; Holzer, B; Koop, I; Koratzinos, M; Jowett, John M; Levichev, E B; Medina, L; Ohmi, K; Papaphilippou, Y; Piminov, P A; Shatilov, D N; Sinyatkin, S V; Sullivan, M; Wenninger, J; Wienands, U; Zhou, D; Zimmermann, F

    2017-01-01

    A beam optics scheme has been designed [ 1 ] for the Future Circular Collider- e + e − (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [ 2 ] with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system without additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So- called “tapering" of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) [ 3 ] as clos...

  15. LHC - latest in a long line of rings

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-12-15

    The LHC - Large Hadron Collider - ring in CERN's 27-kilometre LEP tunnel is the natural next link in an accelerator chain first forged in the mid-1950s with the decision to build Europe's first state-of-the-art high energy synchrotron at CERN. A lot of ground has been covered since the LHC idea was launched over a decade ago. While the basic machine design has moved through several iterations, preparations for the experimental programme are well underway. CERN is now responding to the December 1991 request from its governing body, Council, to supply detailed information on the technical feasibility of the machine, its costs, and its experimental programme. In the late 1970s, when plans for CERN's LEP electron-positron collider were being pieced together, far-sighted people were already looking further ahead. With the LEP tunnel itself a major investment for the future, the circumference of the ring and the tunnel cross-section were kept as large as possible, so that another ring could be fitted in when the time came. On the physics front, the ultimate quest was the mysterious higgs mechanism which controls electroweak symmetry breaking. The symmetry of the vacuum is broken by the higgs field. Somewhere along the line, this fundamental field has to show itself as one or more higgs particles.

  16. LHC - latest in a long line of rings

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The LHC - Large Hadron Collider - ring in CERN's 27-kilometre LEP tunnel is the natural next link in an accelerator chain first forged in the mid-1950s with the decision to build Europe's first state-of-the-art high energy synchrotron at CERN. A lot of ground has been covered since the LHC idea was launched over a decade ago. While the basic machine design has moved through several iterations, preparations for the experimental programme are well underway. CERN is now responding to the December 1991 request from its governing body, Council, to supply detailed information on the technical feasibility of the machine, its costs, and its experimental programme. In the late 1970s, when plans for CERN's LEP electron-positron collider were being pieced together, far-sighted people were already looking further ahead. With the LEP tunnel itself a major investment for the future, the circumference of the ring and the tunnel cross-section were kept as large as possible, so that another ring could be fitted in when the time came. On the physics front, the ultimate quest was the mysterious higgs mechanism which controls electroweak symmetry breaking. The symmetry of the vacuum is broken by the higgs field. Somewhere along the line, this fundamental field has to show itself as one or more higgs particles

  17. Rings in drugs.

    Science.gov (United States)

    Taylor, Richard D; MacCoss, Malcolm; Lawson, Alastair D G

    2014-07-24

    We have analyzed the rings, ring systems, and frameworks in drugs listed in the FDA Orange Book to understand the frequency, timelines, molecular property space, and the application of these rings in different therapeutic areas and target classes. This analysis shows that there are only 351 ring systems and 1197 frameworks in drugs that came onto the market before 2013. Furthermore, on average six new ring systems enter drug space each year and approximately 28% of new drugs contain a new ring system. Moreover, it is very unusual for a drug to contain more than one new ring system and the majority of the most frequently used ring systems (83%) were first used in drugs developed prior to 1983. These observations give insight into the chemical novelty of drugs and potentially efficient ways to assess compound libraries and develop compounds from hit identification to lead optimization and beyond.

  18. The PEP [positron-electron-proton] electron-positron ring: An update

    International Nuclear Information System (INIS)

    1975-03-01

    The first stage of the positron-electron-protron (PEP) colliding-beam system, which has been under joint study by a Lawrence Berkeley Laboratory--Stanford Linear Accelerator Center team for the past two years, will be the electron-positron storage ring. The physics justification for the e + e/sup /minus// ring is summarized briefly and the proposed facility is described. The ring will have six arcs having gross radii of about 220 m and six interaction regions located at the centers of straight sections about 130 m long. The longitudinal distance left free for experimental apparatus around the interaction regions was set provisionally at 20 m. The range of operating beam energies will be from 5 GeV to 15 GeV. The design luminosity at 15 GeV will be 10 32 cm/sup /minus/2/s/sup /minus/1/, and the luminosity will vary approximately as the square of the beam energy. Alternative methods under consideration for adjusting the beam cross section are discussed. The designs of the storage ring subsystems and of the conventional facilities including the experimental halls at the interaction regions are described. 7 figs., 3 tabs

  19. CT demonstration of chicken trachea resulting from complete cartilaginous rings of the trachea in ring-sling complex

    International Nuclear Information System (INIS)

    Calcagni, Giulio; Bonnet, Damien; Sidi, Daniel; Brunelle, Francis; Vouhe, Pascal; Ou, Phalla

    2008-01-01

    We report a 10-month-old infant who presented with tetralogy of Fallot and respiratory disease in whom the suspicion of a ring-sling complex was confirmed by high-resolution CT. CT demonstrated the typical association of left pulmonary artery sling and the ''chicken trachea'' resulting from complete cartilaginous rings of the trachea. (orig.)

  20. The influence of climate variability on polar bear (Ursus maritimus) and ringed seal (Pusa hispida) population dynamics

    DEFF Research Database (Denmark)

    Rosing-Asvid, A.

    2006-01-01

    Unusually high polar bear (Ursus maritimus Phipps, 1774) predation on ringed seal (Pusa hispida (Schreber, 1775)) pups and increased survival of polar bear cubs during mild springs is documented in published articles. Strong predation on newborn ringed seal pups in early spring, however, is likely...... to lower the overall energy intake of polar bears if ringed seal pups are their main food, because the energetic value of ringed seal pups increases 7-8 times during the 6 week lactation period. So although hunting success in early spring increases cub survival during the period after den emergence......,when they are most vulnerable, it is likely to increase the number of starving bears later in the season. This negative-feedback effect of strong spring predation will not occur in areas where other seal species are abundant during summer, and polar bears in such areas are likely to exhibit population growth during...

  1. Department of High Energy Physics: Overview

    International Nuclear Information System (INIS)

    Nassalski, J.

    2000-01-01

    Full text: The activities of the Department of High Energy Physics are centered around experiments performed at accelerators in the following laboratories: 1. At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: - DELPHI at LEP e + e - storage ring is concerned mainly with the tests of the Standard Model, b-quark physics, gamma-gamma interactions and search for Higgs boson and supersymmetric particles; - NA48 - studies of the CP-violation in rare K 0 decays; - SMC - Spin Muon Collaboration is investigating the spin dependent nucleon structure functions and the gluon role in the nucleon spin; - NA49 and WA98 deal with heavy ion physics looking for possible effects of the phase transition to the quark-gluon plasma state. 2. At CELSIUS Storage Ring in Uppsala, Sweden: - WASA - the production of light mesons near threshold and their rare decays. 3. At DESY in Hamburg, Germany: - ZEUS - deep inelastic scattering of electrons and protons, proton structure functions, diffractive photon-proton interactions. The groups of our Department participated in the construction phase of the experiments, both in hardware and in development of the software used in data analysis. Presently they take part in the data acquisition, detector performance supervision and data analysis. The Department is also actively involved in the preparation of new experiments: - CMS (Compact Muon Solenoid) and LHCb (b-quark production and CP-violation) at the LHC (Large Hadron Collider) at CERN, - ALICE - experiment to study the heavy ion interactions at the LHC, - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) at the SPS at CERN, - WASA-Promice - a new version of the WASA detector at CELSIUS in Uppsala, - relativistic hyperfragment production experiment in Dubna, Russia. A small mechanical workshop is attached to our Department. It is involved in the preparation of the COMPASS experiment and participated in the construction of the WASA - Promice

  2. Department of High Energy Physics: Overview

    International Nuclear Information System (INIS)

    Bialkowska, H.

    2002-01-01

    Full text:The activities of the Department of High Energy Physics are centered around experiments performed at accelerators in the following laboratories: * At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: - DELPHI at LEP e + e - storage ring - the tests of the Standard Model, b-quark physics, gamma-gamma interactions and search for Higgs boson and supersymmetric particles - NA48 - the CP-violation and rare K 0 decays - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) - studies the gluon polarization in the nucleon - NA49 and WA98 - heavy ion physics, looking for possible effects of the phase transition to the quark-gluon plasma state. * At CELSIUS Storage Ring in Uppsala, Sweden: - WASA - a precise study of near threshold resonance production. * At DESY in Hamburg, Germany: - ZEUS - deep inelastic scattering of electrons and protons, proton structure functions, diffractive photon-proton interactions. * Super-Kamiokande and Icarus - neutrino mass and oscillations study. The groups of our Department participated in the construction phase of the experiments, both in hardware and in development of the software used in data analysis. Presently they take part in the data collection, detector performance supervision and data analysis. The Department is also actively involved in the preparation of new experiments: - CMS (Compact Muon Solenoid) at the LHC, - LHCb (b-quark production and CP-violation) at the LHC (Large Hadron Collider) at CERN, - ALICE - experiment to study the heavy ion interactions at the LHC, - ICARUS - tests of a liquid argon TPC, in preparation, for neutrino beam (CERN to Gran Sasso), and to be used for cosmic neutrino detection, - study of charge exchange processes in d-p collisions at Nuclotron in Dubna. A mechanical workshop attached to our Department, participated in the construction of the prototypes for the alignment monitoring system for the Outer Tracker detector in the LHCb experiment. Now

  3. Department of High Energy Physics: Overview

    International Nuclear Information System (INIS)

    Bialkowska, H.

    2003-01-01

    Full text: The activities of the Department of High Energy Physics are centered around experiments performed at accelerators in the following laboratories: - At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: - DELPHI at LEP e + e - storage ring - the tests of the Standard Model, b-quark physics, gamma-gamma interactions and search for Higgs boson and supersymmetric particles - NA48 - - the CP-violation and rare K 0 decays - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) - studies the gluon polarization in the nucleon - NA49 and WA98 - heavy ion physics, looking for possible effects of the phase transition to the quark-gluon plasma state. - At CELSIUS Storage Ring in Uppsala, Sweden: - WASA - a precise study of near threshold resonance production. - At DESY in Hamburg, Germany: - ZEUS - deep inelastic scattering of electrons and protons, proton structure functions, diffractive photon-proton interactions. - Super-Kamiokande and Icarus - neutrino mass and oscillation studies. The groups of our Department participated in the construction phase of the experiments, both in hardware and in the development of the software used in data analysis. Presently they take part in data collection, detector performance supervision and data analysis. The Department is also involved in the preparation of new experiments: - CMS (Compact Muon Solenoid) at the LHC, - LHCb (b-quark production and CP-violation) at the LHC (Large Hadron Collider) at CERN, - ALICE - experiment to study the heavy ion interactions at the LHC, - ICARUS - tests of a liquid argon TPC, in preparation, for neutrino beam (CERN to Gran Sasso), and to be used for cosmic neutrino detection, - the study of charge exchange processes in d-p collisions at Nuclotron in Dubna. A mechanical workshop attached to our Department participated in the construction of the prototypes for the alignment monitoring system for the Outer Tracker detector in the LHCb experiment. Now a

  4. High and ultra-high vacuum pumping techniques: applications in accelerators and storage rings

    International Nuclear Information System (INIS)

    Schaefer, G.

    1988-01-01

    A survey is given on gas transfer pumps, especially Turbomolecular pumps, and entrapment pumps (cryopumps and getter pumps) mainly with regard to their application in evacuating particle accelerators and storage rings. (A.C.A.S.) [pt

  5. Numerical investigation of a vortex ring impinging on a coaxial aperture

    Science.gov (United States)

    Hu, Jiacheng; Peterson, Sean D.

    2017-11-01

    Recent advancements in smart materials have sparked an interest in the development of small scale fluidic energy harvesters for powering distributed applications in aquatic environments, where coherent vortex structures are prevalent. Thus, it is crucial to investigate the interaction of viscous vortices in the proximity of a thin plate (a common harvester configuration). Hence, the present study systematically examines the interaction of a vortex ring impinging on an infinitesimally thin wall with a coaxially aligned annular aperture. The rigid aperture serves as an axisymmetric counterpart of the thin plate, and the vortex ring represents a typical coherent vortex structure. The results indicate that the vortex dynamics can be categorized into two regimes based on the aperture to ring radius ratio (Rr). The rebound regime (Rr = 0.9 , and an increase in the vortex ring impulse is observed for 1.0 energy harvesting strategy in vortex impact configurations. This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant (RGPIN-05778) and Alexander Graham Bell Canada Graduate Scholarship (CGS-D).

  6. 4-twist helix snake to maintain polarization in multi-GeV proton rings

    Directory of Open Access Journals (Sweden)

    F. Antoulinakis

    2017-09-01

    Full Text Available Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven’s 255 GeV Relativistic Heavy Ion Collider (RHIC, use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab’s 120  GeV/c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9–120  GeV/c range. We found that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. This snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.

  7. Storage ring development at the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Krinsky, S.; Bittner, J.; Fauchet, A.M.; Johnson, E.D.; Keane, J.; Murphy, J.; Nawrocky, R.J.; Rogers, J.; Singh, O.V.; Yu, L.H.

    1991-09-01

    This report contains papers on the following topics: Transverse Beam Profile Monitor; Bunch Length Measurements in the VUV Storage Ring; Photoelectric Effect Photon Beam Position Monitors; RF Receivers for Processing Electron Beam Pick-up Electrode Signals; Real-Time Global Orbit Feedback Systems; Local Orbit Feedback; Active Interlock System for High Power Insertion Devices in the X-ray Ring; Bunch Lengthening Cavity for the VUV Ring; SXLS Storage Ring Design

  8. Why high energy physics

    International Nuclear Information System (INIS)

    Diddens, A.N.; Van de Walle, R.T.

    1981-01-01

    An argument is presented for high energy physics from the point of view of the practitioners. Three different angles are presented: The cultural consequence and scientific significance of practising high energy physics, the potential application of the results and the discovery of high energy physics, and the technical spin-offs from the techniques and methods used in high energy physics. (C.F.)

  9. Structural and thermodynamic aspects of the dissociation of cyclopentadienyl rings from homoleptic cyclopentadienyl early transition metal, cerium, and thorium derivatives

    International Nuclear Information System (INIS)

    Peng Bin; Cheng Feng; Li Qianshu; Xie Yaoming; King, R. Bruce; Schaefer, Henry F.

    2011-01-01

    Graphical abstract: Density functional theory indicates that for Cp 4 M the S 4 structures are saddle points and the minima have C 1 symmetry with all η 5 -Cp rings for M = Ce and Th, three η 5 -Cp rings and one η 5 -Cp ring for M = Zr, and two η 5 -Cp rings and two η 5 -Cp rings for M = Ti and Hf. The dissociation energies for Cp 4 M → Cp 3 M + Cp · increase in the sequence Ti 3h structures with all η 5 -Cp rings are genuine minima for most of the Cp 3 M compounds except for Cp 3 Ti, which has a Cs symmetry minimum with two η 5 -Cp rings and one η 2 -Cp ring. The dissociation energies for Cp 3 M → Cp 2 M + Cp · increase in the sequence V 4 M the S 4 structures are saddle points. → The minima for Cp 4 M have all η 5 -Cp rings for M = Ce and Th, three η 5 -Cp rings and one η 1 -Cp ring for M = Zr, and two η 5 -Cp rings and two η 5 -Cp rings for M = Ti and Hf. → The dissociation energies for Cp 4 M → Cp 3 M + Cp · increase in the sequence Ti 3h structures with all η 5 -Cp rings are genuine minima for all of the Cp 3 M compounds except for Cp 3 Ti. → The dissociation energies for Cp 3 M → Cp 2 M + Cp · increase in the sequence V 4 M (M = Ti, Zr, Ce, Hf, Th), Cp 3 M (M = Sc, Y, most lanthanides, Ti, Zr, Hf, Th), and Cp 2 M (M = Ti, V). Density functional theory shows that the Cp 4 M structures with unusual S 4 symmetry are saddle points for the d-block metals Ti, Zr, Hf but genuine minima for the f-block metals Ce and Th. The true equilibrium Cp 4 M geometries have C 1 symmetry with two η 5 -Cp rings and two η 1 -Cp rings for M = Ti and Hf but three η 5 -Cp rings and one η 1 -Cp ring for M = Zr. The dissociation energies for Cp 4 M → Cp 3 M + Cp · are substantial and in the order Ti 3h structures with all η 5 -Cp rings are genuine minima for most of the Cp 3 M compounds except for Cp 3 Ti, which has a C s symmetry minimum with two η 5 -Cp rings and one η 2 -Cp ring, and Cp 3 V, which has two η 5 -Cp rings and one η 1 -Cp ring

  10. CT demonstration of chicken trachea resulting from complete cartilaginous rings of the trachea in ring-sling complex

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Giulio; Bonnet, Damien; Sidi, Daniel [University Paris Descartes, Department of Paediatric Cardiology, Hopital Necker-Enfants Malades, AP-HP, Paris (France); Brunelle, Francis [University Paris Descartes, Department of Paediatric Radiology, Hopital Necker-Enfants Malades, AP-HP, Paris Cedex 15 (France); Vouhe, Pascal [University Paris Descartes, Department of Paediatric Cardiovascular Surgery, Hopital Necker-Enfants Malades, AP-HP, Paris (France); Ou, Phalla [University Paris Descartes, Department of Paediatric Cardiology, Hopital Necker-Enfants Malades, AP-HP, Paris (France); University Paris Descartes, Department of Paediatric Radiology, Hopital Necker-Enfants Malades, AP-HP, Paris Cedex 15 (France)

    2008-07-15

    We report a 10-month-old infant who presented with tetralogy of Fallot and respiratory disease in whom the suspicion of a ring-sling complex was confirmed by high-resolution CT. CT demonstrated the typical association of left pulmonary artery sling and the ''chicken trachea'' resulting from complete cartilaginous rings of the trachea. (orig.)

  11. Unique double concentric ring organization of light harvesting complexes in Gemmatimonas phototrophica.

    Directory of Open Access Journals (Sweden)

    Marko Dachev

    2017-12-01

    Full Text Available The majority of life on Earth depends directly or indirectly on the sun as a source of energy. The initial step of photosynthesis is facilitated by light-harvesting complexes, which capture and transfer light energy into the reaction centers (RCs. Here, we analyzed the organization of photosynthetic (PS complexes in the bacterium G. phototrophica, which so far is the only phototrophic representative of the bacterial phylum Gemmatimonadetes. The isolated complex has a molecular weight of about 800 ± 100 kDa, which is approximately 2 times larger than the core complex of Rhodospirillum rubrum. The complex contains 62.4 ± 4.7 bacteriochlorophyll (BChl a molecules absorbing in 2 distinct infrared absorption bands with maxima at 816 and 868 nm. Using femtosecond transient absorption spectroscopy, we determined the energy transfer time between these spectral bands as 2 ps. Single particle analyses of the purified complexes showed that they were circular structures with an outer diameter of approximately 18 nm and a thickness of 7 nm. Based on the obtained, we propose that the light-harvesting complexes in G. phototrophica form 2 concentric rings surrounding the type 2 RC. The inner ring (corresponding to the B868 absorption band is composed of 15 subunits and is analogous to the inner light-harvesting complex 1 (LH1 in purple bacteria. The outer ring is composed of 15 more distant BChl dimers with no or slow energy transfer between them, resulting in the B816 absorption band. This completely unique and elegant organization offers good structural stability, as well as high efficiency of light harvesting. Our results reveal that while the PS apparatus of Gemmatimonadetes was acquired via horizontal gene transfer from purple bacteria, it later evolved along its own pathway, devising a new arrangement of its light harvesting complexes.

  12. Phase behaviour of polyethylene knotted ring chains

    International Nuclear Information System (INIS)

    Wen Xiao-Hui; Xia A-Gen; Chen Hong-Ping; Zhang Lin-Xi

    2011-01-01

    The phase behaviour of polyethylene knotted ring chains is investigated by using molecular dynamics simulations. In this paper, we focus on the collapse of the polyethylene knotted ring chain, and also present the results of linear and ring chains for comparison. At high temperatures, a fully extensive knot structure is observed. The mean-square radius of gyration per bond (S 2 )/(Nb 2 ) and the shape factor (δ*) depend on not only the chain length but also the knot type. With temperature decreasing, chain collapse is observed, and the collapse temperature decreases with the chain length increasing. The actual collapse transition can be determined by the specific heat capacity C v , and the knotted ring chain undergoes gas—liquid—solid-like transition directly. The phase transition of a knotted ring chain is only one-stage collapse, which is different from the polyethylene linear and ring chains. This investigation can provide some insights into the statistical properties of knotted polymer chains. (condensed matter: structural, mechanical, and thermal properties)

  13. Transcatheter Mitral Valve-in-Ring Implantation

    LENUS (Irish Health Repository)

    Tanner, RE

    2018-05-01

    Failed surgical mitral valve repair using an annuloplasty ring has traditionally been treated with surgical valve replacement or repair1. For patients at high risk for repeat open heart surgery, placement of a trans-catheter aortic valve (i.e., TAVI valve) within the mitral ring (i.e., Mitral-Valve-in-Ring, MViR) has emerged as a novel alternative treatment strategy2-5 . We describe our experience of a failed mitral valve repair that was successfully treated with a TAVI valve delivered via the trans-septal approach, and summarise the data relating to this emerging treatment strategy.

  14. Ring-like spatial distribution of laser accelerated protons in the ultra-high-contrast TNSA-regime

    Science.gov (United States)

    Becker, G. A.; Tietze, S.; Keppler, S.; Reislöhner, J.; Bin, J. H.; Bock, L.; Brack, F.-E.; Hein, J.; Hellwing, M.; Hilz, P.; Hornung, M.; Kessler, A.; Kraft, S. D.; Kuschel, S.; Liebetrau, H.; Ma, W.; Polz, J.; Schlenvoigt, H.-P.; Schorcht, F.; Schwab, M. B.; Seidel, A.; Zeil, K.; Schramm, U.; Zepf, M.; Schreiber, J.; Rykovanov, S.; Kaluza, M. C.

    2018-05-01

    The spatial distribution of protons accelerated from submicron-thick plastic foil targets using multi-terawatt, frequency-doubled laser pulses with ultra-high temporal contrast has been investigated experimentally. A very stable, ring-like beam profile of the accelerated protons, oriented around the target’s normal direction has been observed. The ring’s opening angle has been found to decrease with increasing foil thicknesses. Two-dimensional particle-in-cell simulations reproduce our results indicating that the ring is formed during the expansion of the proton density distribution into the vacuum as described by the mechanism of target-normal sheath acceleration. Here—in addition to the longitudinal electric fields responsible for the forward acceleration of the protons—a lateral charge separation leads to transverse field components accelerating the protons in the lateral direction.

  15. PEP-X: An Ultimate Storage Ring Based on Fourth-Order Geometric Achromats

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai; Bane, Karl; Hettel, Robert; Nosochkov, Yuri; Wang, Min-Huey; /SLAC

    2012-04-06

    We have designed an 'ultimate' storage ring for the PEP-X light source that achieves the diffraction limited emittances (at 1.5 {angstrom}) of 12 pm-rad in both horizontal and vertical planes with a 4.5-GeV beam. These emittances include the contribution of intrabeam scattering at a nominal current of 200 mA in 3300 bunches. This quality beam in conjunction with a conventional 4-m undulator in a straight section can generate synchrotron radiation having a spectral brightness above 10{sup 22} [photons/s/mm{sup 2}/mrad{sup 2}/0.1% BW] at a 10 keV photon energy. The high coherence at the diffraction limit makes PEP-X competitive with 4th generation light sources based on an energy recovery linac. In addition, the beam lifetime is several hours and the dynamic aperture is large enough to allow off-axis injection. The alignment and stability tolerances, though challenging, are achievable. A ring with all these properties is only possible because of several major advances in mitigating the effects of nonlinear resonances.

  16. Apple ring rot-responsive putative microRNAs revealed by high-throughput sequencing in Malus × domestica Borkh.

    Science.gov (United States)

    Yu, Xin-Yi; Du, Bei-Bei; Gao, Zhi-Hong; Zhang, Shi-Jie; Tu, Xu-Tong; Chen, Xiao-Yun; Zhang, Zhen; Qu, Shen-Chun

    2014-08-01

    MicroRNAs (miRNAs) are small non-coding RNAs, which silence target mRNA via cleavage or translational inhibition to function in regulating gene expression. MiRNAs act as important regulators of plant development and stress response. For understanding the role of miRNAs responsive to apple ring rot stress, we identified disease-responsive miRNAs using high-throughput sequencing in Malus × domestica Borkh.. Four small RNA libraries were constructed from two control strains in M. domestica, crabapple (CKHu) and Fuji Naga-fu No. 6 (CKFu), and two disease stress strains, crabapple (DSHu) and Fuji Naga-fu No. 6 (DSFu). A total of 59 miRNA families were identified and five miRNAs might be responsive to apple ring rot infection and validated via qRT-PCR. Furthermore, we predicted 76 target genes which were regulated by conserved miRNAs potentially. Our study demonstrated that miRNAs was responsive to apple ring rot infection and may have important implications on apple disease resistance.

  17. Study on leakage rates of high temperature water from wet-type transport casks for spent fuel. Pt. 2. Leakage rates from a scratch on O-ring surface and narrow wires adhering to O-ring surface

    International Nuclear Information System (INIS)

    Asano, R.; Aritomi, M.; Sudi, A.; Kohketsu, Y.

    1997-01-01

    A programme for enhancement of fuel burnup has been promoted in Japan as part of the sophisticated programme for light water reactors to reduce the fuel cost and the amount of spent fuel. As part of this fuel programme, a new wet-type transport cask has been developed to transport the high burnup fuels efficiently. The purpose of this work is to clarify the margin of safety in the evaluation of the release rate of radioactive materials from the wet-type transport cask into the environment and to establish a practical evaluation method for leakage rates on leak behaviour of high temperature water from the casks. In this paper, leakage rates of water under high pressures and at high temperatures are investigated from two kinds of leak path model. One is a disc with a scratch on the surface which simulates a defect on the seal surface of the O-ring flange and the other is narrow stainless steel wires installed on the O-ring surface which simulates hair adhering to the O-ring surface. From the results, an evaluation method for the leakage rate of water under high pressure and at high temperature from a non-circular leak path and multiple leak paths is proposed. (author)

  18. Dispersion engineering of thick high-Q silicon nitride ring-resonators via atomic layer deposition.

    Science.gov (United States)

    Riemensberger, Johann; Hartinger, Klaus; Herr, Tobias; Brasch, Victor; Holzwarth, Ronald; Kippenberg, Tobias J

    2012-12-03

    We demonstrate dispersion engineering of integrated silicon nitride based ring resonators through conformal coating with hafnium dioxide deposited on top of the structures via atomic layer deposition. Both, magnitude and bandwidth of anomalous dispersion can be significantly increased. The results are confirmed by high resolution frequency-comb-assisted-diode-laser spectroscopy and are in very good agreement with the simulated modification of the mode spectrum.

  19. Four faces of the interaction between ions and aromatic rings.

    Science.gov (United States)

    Papp, Dóra; Rovó, Petra; Jákli, Imre; Császár, Attila G; Perczel, András

    2017-07-15

    Non-covalent interactions between ions and aromatic rings play an important role in the stabilization of macromolecular complexes; of particular interest are peptides and proteins containing aromatic side chains (Phe, Trp, and Tyr) interacting with negatively (Asp and Glu) and positively (Arg and Lys) charged amino acid residues. The structures of the ion-aromatic-ring complexes are the result of an interaction between the large quadrupole moment of the ring and the charge of the ion. Four attractive interaction types are proposed to be distinguished based on the position of the ion with respect to the plane of the ring: perpendicular cation-π (CP ⊥ ), co-planar cation-π (CP ∥ ), perpendicular anion-π (AP ⊥ ), and co-planar anion-π (AP ∥ ). To understand more than the basic features of these four interaction types, a systematic, high-level quantum chemical study is performed, using the X -  + C 6 H 6 , M +  + C 6 H 6 , X -  + C 6 F 6 , and M +  + C 6 F 6 model systems with X -  = H - , F - , Cl - , HCOO - , CH 3 COO - and M +  = H + , Li + , Na + , NH4+, CH 3 NH3+, whereby C 6 H 6 and C 6 F 6 represent an electron-rich and an electron-deficient π system, respectively. Benchmark-quality interaction energies with small uncertainties, obtained via the so-called focal-point analysis (FPA) technique, are reported for the four interaction types. The computations reveal that the interactions lead to significant stabilization, and that the interaction energy order, given in kcal mol -1 in parentheses, is CP ⊥ (23-37) > AP ⊥ (14-21) > CP ∥ (9-22) > AP ∥ (6-16). A natural bond orbital analysis performed leads to a deeper qualitative understanding of the four interaction types. To facilitate the future quantum chemical characterization of ion-aromatic-ring interactions in large biomolecules, the performance of three density functional theory methods, B3LYP, BHandHLYP, and M06-2X, is tested against the FPA benchmarks

  20. Persistent current in triangle silicene rings with spin–orbit interaction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ning, E-mail: nxu@ycit.cn [Department of Physics, Yancheng Institute of Technology, Yancheng 224051 (China); Zhang, Haiyang; Wu, Xiuqiang; Bai, Yujie [Department of Physics, Yancheng Institute of Technology, Yancheng 224051 (China); Ding, Jianwen, E-mail: jwding@xtu.edu.cn [Department of Physics, Xiangtan University, Xiangtan 411105 (China)

    2017-06-28

    The energy spectrum and magnetic response of triangle silicene rings (TSRs) are investigated within the tight-binding model. It is shown that the flux-dependent energy spectrum is divided into bands, with three levels per band, owing to the three-fold rotational symmetry structure of TSRs. The zigzag TSRs are metallic, exhibiting either diamagnetic or paramagnetic response depending on the size of inner ring radius. Armchair TSRs are semiconducting, exhibiting diamagnetic response. Taking into account the intrinsic spin–orbit interaction, the magnetic-field-driven spin-up electrons flow anticlockwise around the TSRs and the spin-down electrons flow clockwise around the TSRs. Additionally, paramagnetism–diamagnetism or diamagnetism–paramagnetism transitions are observed with the increase of exchange field. The results may be very helpful for the design and application of TSR-based nanodevices. - Highlights: • The zigzag TSRs are metallic. • Armchair TSRs which exhibit diamagnetic response are semiconducting. • The spin-up electrons flow anticlockwise and spin-down electrons flow clockwise around the rings.