WorldWideScience

Sample records for charged particle accelerators

  1. The charged particle accelerators subsystems modeling

    Science.gov (United States)

    Averyanov, G. P.; Kobylyatskiy, A. V.

    2017-01-01

    Presented web-based resource for information support the engineering, science and education in Electrophysics, containing web-based tools for simulation subsystems charged particle accelerators. Formulated the development motivation of Web-Environment for Virtual Electrophysical Laboratories. Analyzes the trends of designs the dynamic web-environments for supporting of scientific research and E-learning, within the framework of Open Education concept.

  2. Electrophysical Systems Based On Charged Particle Accelerators

    CERN Document Server

    Vorogushin, M F

    2004-01-01

    The advancement of the charged particle accelerator engineering affects appreciably the modern tendencies of the scientific and technological progress in the world. In a number of advanced countries, this trend is one of the most dynamically progressing in the field of applied science and high-technology production. Such internationally known firms as VARIAN, SIEMENS, PHILIPS, ELECTA, IBA, HITACHI, etc., with an annual budget of milliards of dollars and growth rate of tens of percent may serve as an example. Although nowadays the projects of new large-scale accelerators for physical research are not implemented so quickly and frequently as desired, accelerating facilities are finding ever-widening application in various fields of human activities. The contribution made by Russian scientists into high-energy beams physics is generally known. High scientific and technical potential in this field, qualified personnel with a high creative potential, modern production and test facilities and state-of-the-art techn...

  3. Accelerators for heavy-charged-particle radiation therapy.

    Science.gov (United States)

    Coutrakon, George B

    2007-08-01

    This paper focuses on current and future designs of medical hadron accelerators for treating cancers and other diseases. Presently, five vendors and several national laboratories have produced heavy-particle medical accelerators for accelerating nuclei from hydrogen (protons) up through carbon and oxygen. Particle energies are varied to control the beam penetration depth in the patient. As of the end of 2006, four hospitals and one clinic in the United States offer proton treatments; there are five more such facilities in Japan. In most cases, these facilities use accelerators designed explicitly for cancer treatments. The accelerator types are a combination of synchrotrons, cyclotrons, and linear accelerators; some carry advanced features such as respiration gating, intensity modulation, and rapid energy changes, which contribute to better dose conformity on the tumor when using heavy charged particles. Recent interest in carbon nuclei for cancer treatment has led some vendors to offer carbon-ion and proton capability in their accelerator systems, so that either ion can be used. These features are now being incorporated for medical accelerators in new facilities.

  4. Harmonic Ratcheting for Ferrite Tuned RF Acceleration of Charged Particles

    Science.gov (United States)

    Cook, Nathan; Brennan, Mike

    2013-04-01

    One of the most persistent difficulties in the design of RF cavities for acceleration of charged particles is the rapid and efficient acceleration of particles over a large range of frequencies. From medical synchrotrons to accelerator driven systems, there is a strong need for fast acceleration of protons and light ions over hundreds of MeV. Conventionally, this is a costly undertaking, requiring specially designed ferrite loaded cavities to be tuned over a large range of frequencies. Ferromagnetic materials allow for the precise adjustment of cavity resonant frequency, but rapid changes in the frequency as well as operation outside material specific frequency ranges result in significant Q-loss to the cavity. This leads to a considerable increase in power required and is thus undesirable for regular operation. We introduce an acceleration scheme known as harmonic ratcheting which can be used to reduce the cavity frequency range needed for accelerating an ion beam in a synchrotron. In particular, this scheme addresses the need for high rep. rate machines for applications such as radiation therapy in which low beam intensity is needed. We demonstrate with simulations the type of ramps achievable using this technique and consider its advantages over h=1 acceleration schemes.

  5. Uniformly Accelerating Charged Particles A Threat to the Equivalence Principle

    CERN Document Server

    Lyle, Stephen N

    2008-01-01

    There has been a long debate about whether uniformly accelerated charges should radiate electromagnetic energy and how one should describe their worldline through a flat spacetime, i.e., whether the Lorentz-Dirac equation is right. There are related questions in curved spacetimes, e.g., do different varieties of equivalence principle apply to charged particles, and can a static charge in a static spacetime radiate electromagnetic energy? The problems with the LD equation in flat spacetime are spelt out in some detail here, and its extension to curved spacetime is discussed. Different equivalence principles are compared and some vindicated. The key papers are discussed in detail and many of their conclusions are significantly revised by the present solution.

  6. Suprathermal Charged Particle Acceleration by Small-scale Flux Ropes.

    Science.gov (United States)

    Zank, G. P.; le Roux, J. A.; Webb, G. M.

    2015-12-01

    We consider different limits of our recently developed kinetic transport theory to investigate the potential of super-Alvenic solar wind regions containing several small-scale flux ropes to explain the acceleration of suprathermal ions to power-law spectra as observations show. Particle acceleration is modeled in response to flux-rope activity involving contraction, merging (reconnection), and collisions in the limit where the particle gyoradius is smaller than the characteristic flux-rope scale length. The emphasis is mainly on the statistical variance in the electric fields induced by flux-rope dynamics rather than on the mean electric field induced by multiple flux ropes whose acceleration effects are discussed elsewhere. Our steady-state analytical solutions suggest that particle drift acceleration by flux ropes, irrespective of whether displaying incompressible or compressible behavior, can yield power laws asymptotically at higher energies whereas an exponential spectral rollover results asymptotically when field-aligned guiding center motion acceleration occur by reconnection electric fields from merging flux ropes. This implies that at sufficiently high particle energies, drift acceleration might dominate. We also expect compressive flux ropes to yield harder power-law spectra than incompressible flux ropes. Preliminary results will be discussed to illustrate how particle acceleration might be affected when both diffusive shock and small-scale flux acceleration occur simultaneously at interplanetary shocks.

  7. Charged particle acceleration by induction electric field in Neptune magnetotail

    Science.gov (United States)

    Vasko, I. Y.; Malova, H. V.; Artemyev, A. V.; Zelenyi, L. M.

    2012-12-01

    The precession of the Neptune magnetic dipole leads to strong dynamics of the magnetosphere and results in continuous transformation from the “Earth-like” configuration to the “pole-on” one and vice versa. In the present work we use simple model of the Neptune magnetotail to investigate the influence of magnetotail topology transformation on particle acceleration and transport through the tail. Energy spectra are obtained for protons penetrating from the solar wind and heavier ions N+ from the Neptune ionosphere. We have found that protons and heavier ions are accelerated up to ∼330 keV and ∼150 keV, respectively. More particles are accelerated and leave the tail during transformations from the “pole-on” configuration to the “Earth-like” one than during inverse transformations. We have shown that the dusk-dawn convection field is responsible for particle leaving through the dawn flank. We briefly compare our results with Voyager-2 observations.

  8. Particle Accelerators in China

    Science.gov (United States)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  9. Rotating Charged Hairy Black Hole in (2+1) Dimensions and Particle Acceleration

    Science.gov (United States)

    Sadeghi, J.; Pourhassan, B.; Farahani, H.

    2014-09-01

    In this paper, we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.

  10. Rotating charged hairy black hole in (2+1) dimensions and particle acceleration

    CERN Document Server

    Sadeghi, J; Farahani, H

    2013-01-01

    In this paper we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.

  11. A New Type of Accelerator for Charged Particle Cancer Therapy

    CERN Document Server

    Edgecock, Rob

    2013-01-01

    acceleration of protons and light ions for the treatment of certain cancers. They have unique features as they combine techniques from the existing types of accelerators, cyclotrons and synchrotrons, and hence look to have advantages over both for this application. However, these unique features meant that it was necessary to build one of these accelerators to show that it works and to undertake a detailed conceptual design of a medical machine. Both of these have now been done. This paper will describe the concepts of this type of accelerator, show results from the proof-of-principle machine (EMMA) and described the medical machine (PAMELA).

  12. A theory of two-beam acceleration of charged particles in a plasma waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Ostrovsky, A.O. [Kharkov Inst. of Physics and Technology (Ukraine)

    1993-11-01

    The progress made in recent years in the field of high-current relativistic electron beam (REB) generation has aroused a considerable interest in studying REB potentialities for charged particle acceleration with a high acceleration rate T = 100MeV/m. It was proposed, in particular, to employ high-current REB in two-beam acceleration schemes (TBA). In these schemes high current REB (driving beam) excites intense electromagnetic waves in the electrodynamic structure which, in their turn, accelerate particles of the other beam (driven beam). The TBA schemes can be divided into two groups. The first group includes the schemes, where the two beams (driving and driven) propagate in different electrodynamic structures coupled with each other through the waveguides which ensure the microwave power transmission to accelerate driven beam particles. The second group includes the TBA schemes, where the driving and driven beams propagate in one electrodynamic structure. The main aim of this work is to demonstrate by theory the possibility of realizing effectively the TBA scheme in the plasma waveguide. The physical model of the TBA scheme under study is formulated. A set of equations describing the excitation of RF fields by a high-current REB and the acceleration of driven beam electrons is also derived. Results are presented on the the linear theory of plasma wave amplification by the driving beam. The range of system parameters, at which the plasma-beam instability develops, is defined. Results of numerical simulation of the TBA scheme under study are also presented. The same section gives the description of the dynamics of accelerated particle bunching in the high-current REB-excited field. Estimates are given for the accelerating field intensities in the plasma and electron acceleration rates.

  13. Acceleration of charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

    CERN Document Server

    Stuchlík, Zdeněk

    2015-01-01

    To test the role of large-scale magnetic fields in accretion processes, we study dynamics of charged test particles in vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes od the charged particle dynamics provides mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is larg...

  14. A novel method for beam misalignment correction of an accelerated charged-particle beam

    Energy Technology Data Exchange (ETDEWEB)

    Rahighi, J. [Van de Graaff Laboratory, Nuclear Science Research School, NSTRI, P.O. Box 14395-836, Tehran, Iran (Iran, Islamic Republic of)]. E-mail: jrahighi@aeoi.org.ir; Lamehi-Rachti, M. [Van de Graaff Laboratory, Nuclear Science Research School, NSTRI, P.O. Box 14395-836, Tehran, Iran (Iran); Kakuee, O.R. [Van de Graaff Laboratory, Nuclear Science Research School, NSTRI, P.O. Box 14395-836, Tehran, Iran (Iran)

    2007-07-21

    A novel method is presented for misalignment correction of an accelerated charged-particle beam in a typical charged-particle scattering experiment employing large-solid-angle detectors. The correction method is based on Rutherford scattering and is quite straightforward to apply when a large solid angle and axially symmetric detection system is used in the experimental measurements. A Monte Carlo computer program and its formalism based on Rutherford scattering cross-section have been described. The program is used to calculate beam misalignment offline after data collection is completed. The method has been successfully applied to correct for misalignment calculated to be typically of the order of a few mm in a {sup 6}He radioactive beam of 27 MeV total energy emerging from a cyclotron and produced via {sup 7}Li(p,2p){sup 6}He reaction.

  15. Impact of the mass and other parameters of charged particles on the results of laser resonance acceleration

    Directory of Open Access Journals (Sweden)

    Adam Dubik

    2014-03-01

    Full Text Available Theoretical and numerical analyses are presented concerning the conditions at which the charged particles of different masses can be accelerated to significant kinetic energy in the circularly polarized laser or maser beams and a static magnetic field. The studies are carried out using the analytical derivations of the particles dynamics and theirs kinetic energy. The presented illustrations enabled interpretation of the complex motion of particles and the possibilities of their acceleration. At the examples of an electron, proton and deuteron, the velocity, kinetic energy and trajectory as a function of the acceleration time at the resonance condition are illustrated in the appropriate graphs. The particles with larger masses require the application of enhanced magnetic field intensity at the resonance condition. However, this field intensity can be significantly reduced if the particles are preaccelerated. [b]Keywords[/b]: optoelectronics, acceleration of charged particles, laser, maser, relativistic dynamics, kinetic energy of a particle, electron, proton, deuteron

  16. The use of radiochromic films to measure and analyze the beam profile of charged particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Avila-Rodriguez, M.A. [Edmonton PET Centre, Cross Cancer Institute, 11560 University Ave, Edmonton, AB T6G 1Z2 (Canada); Unidad PET/CT-Ciclotron, Facultad de Medicina, Universidad Nacional Autonoma de Mexico (Mexico)], E-mail: avilarod@uwalumni.com; Wilson, J.S.; McQuarrie, S.A. [Edmonton PET Centre, Cross Cancer Institute, 11560 University Ave, Edmonton, AB T6G 1Z2 (Canada)

    2009-11-15

    The use of radiochromic films as a simple and inexpensive tool to accurately measure and analyze the beam profile of charged particle accelerators is described. In this study, metallic foils of different materials and thicknesses were irradiated with 17.8 MeV protons and autoradiographic images of the beam strike were acquired by exposing pieces of RCF in direct contact with the irradiated foils. The films were digitalized using a conventional scanner and images were analyzed using DoseLab. Beam intensity distributions, isodose curves and linear beam profiles of the digitalized images were acquired.

  17. The use of radiochromic films to measure and analyze the beam profile of charged particle accelerators.

    Science.gov (United States)

    Avila-Rodriguez, M A; Wilson, J S; McQuarrie, S A

    2009-11-01

    The use of radiochromic films as a simple and inexpensive tool to accurately measure and analyze the beam profile of charged particle accelerators is described. In this study, metallic foils of different materials and thicknesses were irradiated with 17.8MeV protons and autoradiographic images of the beam strike were acquired by exposing pieces of RCF in direct contact with the irradiated foils. The films were digitalized using a conventional scanner and images were analyzed using DoseLab. Beam intensity distributions, isodose curves and linear beam profiles of the digitalized images were acquired.

  18. Pondermotive acceleration of charged particles along the relativistic jets of an accreting blackhole

    Science.gov (United States)

    Ebisuzaki, T.; Tajima, T.

    2014-05-01

    Accreting blackholes such as miniquasars and active galactic nuclei can contribute to the highest energy components of intra- (˜1015 eV) galactic and extra-galactic components (˜1020 eV) of cosmic rays. Alfven wave pulses which are excited in the accretion disk around blackholes propagate in relativistic jets. Because of their highly non-linear nature of the waves, charged particles (protons, ions, and electrons) can be accelerated to high energies in relativistic jets in accreting blackhole systems, the central engine of miniquasars and active galactic nuclei.

  19. A stochastic model for the semiclassical collective dynamics of charged beams in particle accelerators

    CERN Document Server

    De Martino, S; Illuminati, F; Martino, Salvatore De; Siena, Silvio De; Illuminati, Fabrizio

    1999-01-01

    A recent proposal (see quant-ph/9803068) to simulate semiclassical corrections to classical dynamics by suitable classical stochastic fluctuations is applied to the specific instance of charged beam dynamics in particle accelerators. The resulting picture is that the collective beam dynamics, at the leading semiclassical order in Planck constant can be described by a particular diffusion process, the Nelson process, which is time-reversal invariant. Its diffusion coefficient $\\sqrt{N}\\lambda_{c}$ represents a semiclassical unit of emittance (here $N$ is the number of particles in the beam, and $\\lambda_{c}$ is the Compton wavelength). The stochastic dynamics of the Nelson type can be easily recast in the form of a Schroedinger equation, with the semiclassical unit of emittance replacing Planck constant. Therefore we provide a physical foundation to the several quantum-like models of beam dynamics proposed in recent years. We also briefly touch upon applications of the Nelson and Schroedinger formalisms to inc...

  20. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2007-01-01

    Particle Accelerator Physics is an in-depth and comprehensive introduction to the field of high-energy particle acceleration and beam dynamics. Part I gathers the basic tools, recalling the essentials of electrostatics and electrodynamics as well as of particle dynamics in electromagnetic fields. Part II is an extensive primer in beam dynamics, followed in Part III by the introduction and description of the main beam parameters. Part IV is devoted to the treatment of perturbations in beam dynamics. Part V discusses the details of charged particle accleration. Part VI and Part VII introduce the more advanced topics of coupled beam dynamics and the description of very intense beams. Part VIII is an exhaustive treatment of radiation from accelerated charges and introduces important sources of coherent radiation such as synchrotrons and free-electron lasers. Part IX collects the appendices gathering useful mathematical and physical formulae, parameters and units. Solutions to many end-of-chapter problems are give...

  1. Charged particle beams

    CERN Document Server

    Humphries, Stanley

    2013-01-01

    Detailed enough for a text and sufficiently comprehensive for a reference, this volume addresses topics vital to understanding high-power accelerators and high-brightness-charged particle beams. Subjects include stochastic cooling, high-brightness injectors, and the free electron laser. Humphries provides students with the critical skills necessary for the problem-solving insights unique to collective physics problems. 1990 edition.

  2. HIGH ENERGY PARTICLE ACCELERATOR

    Science.gov (United States)

    Courant, E.D.; Livingston, M.S.; Snyder, H.S.

    1959-04-14

    An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.

  3. Developments in accelerators and instrumentation relevant to imaging with charged particles and positron emitters

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, J.R.

    1980-11-01

    In past years particle accelerators have become increasingly important tools for the advancement of medical science. From the pace of advancing technology and current directions in medical research, it is clear that this relationship between accelerators and medicine will only grow stronger in future years. In view of this importance, this relationship is investigated in some detail, with an eye not so much towards the medical uses of the beams produced, but more towards the technology associated with these accelerators and the criteria which make for successful incorporation of these machines into the clinical environment. In order to lay the necessary groundwork, the different kinds of accelerators found in medical use today are reviewed briefly discussing salient points of each.

  4. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2015-01-01

    This book by Helmut Wiedemann is a well-established, classic text, providing an in-depth and comprehensive introduction to the field of high-energy particle acceleration and beam dynamics. The present 4th edition has been significantly revised, updated and expanded. The newly conceived Part I is an elementary introduction to the subject matter for undergraduate students. Part II gathers the basic tools in preparation of a more advanced treatment, summarizing the essentials of electrostatics and electrodynamics as well as of particle dynamics in electromagnetic fields. Part III is an extensive primer in beam dynamics, followed, in Part IV, by an introduction and description of the main beam parameters and including a new chapter on beam emittance and lattice design. Part V is devoted to the treatment of perturbations in beam dynamics. Part VI then discusses the details of charged particle acceleration. Parts VII and VIII introduce the more advanced topics of coupled beam dynamics and describe very intense bea...

  5. Electrostatic wire stabilizing a charged particle beam

    Science.gov (United States)

    Prono, D.S.; Caporaso, G.J.; Briggs, R.J.

    1983-03-21

    In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.

  6. Particle Acceleration in Astrophysical Sources

    CERN Document Server

    Amato, Elena

    2015-01-01

    Astrophysical sources are extremely efficient accelerators. Some sources emit photons up to multi-TeV energies, a signature of the presence, within them, of particles with energies much higher than those achievable with the largest accelerators on Earth. Even more compelling evidence comes from the study of Cosmic Rays, charged relativistic particles that reach the Earth with incredibly high energies: at the highest energy end of their spectrum, these subatomic particles are carrying a macroscopic energy, up to a few Joules. Here I will address the best candidate sources and mechanisms as cosmic particle accelerators. I will mainly focus on Galactic sources such as Supernova Remnants and Pulsar Wind Nebulae, which being close and bright, are the best studied among astrophysical accelerators. These sources are held responsible for most of the energy that is put in relativistic particles in the Universe, but they are not thought to accelerate particles up to the highest individual energies, $\\approx 10^{20}$ eV...

  7. Acceleration of the charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Stuchlik, Zdenek; Kolos, Martin [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Opava (Czech Republic)

    2016-01-15

    To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)

  8. High Energy Particle Accelerators

    CERN Multimedia

    Audio Productions, Inc, New York

    1960-01-01

    Film about the different particle accelerators in the US. Nuclear research in the US has developed into a broad and well-balanced program.Tour of accelerator installations, accelerator development work now in progress and a number of typical experiments with high energy particles. Brookhaven, Cosmotron. Univ. Calif. Berkeley, Bevatron. Anti-proton experiment. Negative k meson experiment. Bubble chambers. A section on an electron accelerator. Projection of new accelerators. Princeton/Penn. build proton synchrotron. Argonne National Lab. Brookhaven, PS construction. Cambridge Electron Accelerator; Harvard/MIT. SLAC studying a linear accelerator. Other research at Madison, Wisconsin, Fixed Field Alternate Gradient Focusing. (FFAG) Oakridge, Tenn., cyclotron. Two-beam machine. Comments : Interesting overview of high energy particle accelerators installations in the US in these early years. .

  9. Cosmic particle acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Zimbardo, Gaetano; Perri, Silvia [Universita della Calabria, Dipartimento di Fisica, 87036 Rende (Italy)

    2014-07-01

    The most popular mechanism for the acceleration of cosmic rays, which is thought to operate in supernova remnant shocks as well as at heliospheric shocks, is the diffusive shock acceleration, which is a Fermi mechanism based on normal diffusion. On the other hand, in the last few years it has been shown that the transport of plasma particles in the presence of electric and magnetic turbulence can be superdiffusive rather than normal diffusive. The term 'superdiffusive' refers to the mean square displacement of particle positions growing superlinearly with time, as compared to the normal linear growth. In particular, superdiffusion is characterized by a non Gaussian statistical process called Levy random walk. We show how diffusive shock acceleration is modified by superdiffusion, and how this yields new predictions for the cosmic ray spectral index, for the acceleration time, and for the spatial profile of energetic particles. A comparison with observations of particle acceleration at heliospheric shocks and at supernova remnant shocks is done. We discuss how superdiffusive shock acceleration allows to explain the observations of hard ion spectra at the solar wind termination shock detected by Voyager 2, of hard radio spectra due to synchrotron emission of electrons accelerated at supernova remnant shocks, and how it can help to explain the observations of 'thin rims' in the X-ray synchrotron emission.

  10. The simulations of charged particle acceleration from gas target at 20 TW SOKOL-P laser with intensity of 5⋅1019 W/cm2

    Directory of Open Access Journals (Sweden)

    Lykov V.A.

    2013-11-01

    Full Text Available 2D PIC code simulations have been performed for the optimization of gas jet target parameters to achieve a maximal energy and efficiency of charged particle acceleration in planned experiments at the 20 TW picosecond SOKOL-P laser. These calculations specify an opportunity to obtain energy up to Ee ∼ 200 MeV and efficiency ηe ∼ 10% for accelerated electrons and Ep ∼ 30 − 50 MeV and ηp ∼ 5% for accelerated protons in these experiments at laser intensity I ∼ 5 ⋅ 1019 W/cm2. They show the necessity of providing a formation of hydrogen jets with diameter ∼ 1mm, a gas molecule concentration ∼ 2 ⋅ 1019 cm−3 and steep density gradients ∼ 200 μm at the edge of the gas jet target for achieving these parameters of laser accelerated particle beams.

  11. Particle-accelerator decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Opelka, J.H.; Mundis, R.L.; Marmer, G.J.; Peterson, J.M.; Siskind, B.; Kikta, M.J.

    1979-12-01

    Generic considerations involved in decommissioning particle accelerators are examined. There are presently several hundred accelerators operating in the United States that can produce material containing nonnegligible residual radioactivity. Residual radioactivity after final shutdown is generally short-lived induced activity and is localized in hot spots around the beam line. The decommissioning options addressed are mothballing, entombment, dismantlement with interim storage, and dismantlement with disposal. The recycle of components or entire accelerators following dismantlement is a definite possibility and has occurred in the past. Accelerator components can be recycled either immediately at accelerator shutdown or following a period of storage, depending on the nature of induced activation. Considerations of cost, radioactive waste, and radiological health are presented for four prototypic accelerators. Prototypes considered range from small accelerators having minimal amounts of radioactive mmaterial to a very large accelerator having massive components containing nonnegligible amounts of induced activation. Archival information on past decommissionings is presented, and recommendations concerning regulations and accelerator design that will aid in the decommissioning of an accelerator are given.

  12. Effects of Turbulent Magnetic Fields on the Transport and Acceleration of Energetic Charged Particles: Numerical Simulations with Application to Heliospheric Physics

    CERN Document Server

    Guo, Fan

    2012-01-01

    After introduction we focus on: the transport of charged particles, the acceleration of ions at shocks, and the acceleration of electrons at shocks. Chapter 2 studies the propagation of solar energetic particles(SEPs) in turbulent magnetic fields. Particle trajectories in turbulent magnetic fields are numerically integrated. The turbulence includes a Kolmogorov-like power spectrum containing a broad range of scales. Small-scale variations in particle intensities(dropouts) and velocity dispersions can be reproduced. The result gives a constraint on the error of onset analysis for inferring SEP informations. We find that dropouts are rarely produced using the two-component model(Matthaeus et al., 1990). The result questions the turbulence model. Chapter 3 studies the acceleration of ions. We use 3-D hybrid simulations to study the acceleration of low-energy particles at parallel shocks. We find that particles gain energy by reflection at the shock. The protons can move off field lines in 3-D electric and magnet...

  13. Electrostatic wire for stabilizing a charged particle beam

    Science.gov (United States)

    Prono, Daniel S.; Caporaso, George J.; Briggs, Richard J.

    1985-01-01

    In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.

  14. A novel adaptive time stepping variant of the Boris-Buneman integrator for the simulation of particle accelerators with space charge

    CERN Document Server

    Toggweiler, Matthias; Arbenz, Peter; Yang, Jianjun J

    2012-01-01

    We show that adaptive time stepping in particle accelerator simulation is an enhancement for certain problems. The new algorithm has been implemented in the OPAL (Object Oriented Parallel Accelerator Library) framework, and is compared to the existing code. The idea is to adjust the frequency of costly self field calculations, which are needed to model Coulomb interaction (space charge) effects. In analogy to a Kepler orbit simulation that requires a higher time step resolution at the close encounter, we propose to choose the time step based on the magnitude of the space charge forces. Inspired by geometric integration techniques, our algorithm chooses the time step proportional to a function of the current phase space state instead of calculating a local error estimate like a conventional adaptive procedure. In this paper we build up on first observations made in recent work. A more profound argument is given on how exactly the time step should be chosen. An intermediate algorithm, initially built to allow a...

  15. Microwave View on Particle Acceleration in Flares

    CERN Document Server

    Fleishman, Gregory D

    2013-01-01

    The thermal-to-nonthermal partition was found to vary greatly from one flare to another resulting in a broad variety of cases from 'heating without acceleration' to 'acceleration without heating'. Recent analysis of microwave data of these differing cases suggests that a similar acceleration mechanism, forming a power-law nonthermal tail up to a few MeV or even higher, operates in all the cases. However, the level of this nonthermal spectrum compared to the original thermal distribution differs significantly from one case to another, implying a highly different thermal-to-nonthermal energy partition in various cases. This further requires a specific mechanism capable of extracting the charged particles from the thermal pool and supplying them to a bulk acceleration process to operate in flares \\textit{in addition} to the bulk acceleration process itself, which, in contrast, efficiently accelerates the seed particles, while cannot accelerate the thermal particles. Within this 'microwave' view on the flare ener...

  16. Introduction to Particle Acceleration in the Cosmos

    Science.gov (United States)

    Gallagher, D. L.; Horwitz, J. L.; Perez, J.; Quenby, J.

    2005-01-01

    Accelerated charged particles have been used on Earth since 1930 to explore the very essence of matter, for industrial applications, and for medical treatments. Throughout the universe nature employs a dizzying array of acceleration processes to produce particles spanning twenty orders of magnitude in energy range, while shaping our cosmic environment. Here, we introduce and review the basic physical processes causing particle acceleration, in astrophysical plasmas from geospace to the outer reaches of the cosmos. These processes are chiefly divided into four categories: adiabatic and other forms of non-stochastic acceleration, magnetic energy storage and stochastic acceleration, shock acceleration, and plasma wave and turbulent acceleration. The purpose of this introduction is to set the stage and context for the individual papers comprising this monograph.

  17. Field calculations, single-particle tracking, and beam dynamics with space charge in the electron lens for the Fermilab Integrable Optics Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Noll, Daniel [Goethe Univ., Frankfurt (Germany); Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-11-17

    An electron lens is planned for the Fermilab Integrable Optics Test Accelerator as a nonlinear element for integrable dynamics, as an electron cooler, and as an electron trap to study space-charge compensation in rings. We present the main design principles and constraints for nonlinear integrable optics. A magnetic configuration of the solenoids and of the toroidal section is laid out. Singleparticle tracking is used to optimize the electron path. Electron beam dynamics at high intensity is calculated with a particle-in-cell code to estimate current limits, profile distortions, and the effects on the circulating beam. In the conclusions, we summarize the main findings and list directions for further work.

  18. Acceleration of small astrophysical grains due to charge fluctuations

    CERN Document Server

    Ivlev, A V; Tsytovich, V N; de Angelis, U; Hoang, Thiem; Morfill, G E

    2010-01-01

    We discuss a novel mechanism of dust acceleration which dominates for particles smaller than $\\sim0.1 \\mu$m. The acceleration is caused by charge fluctuations occurring on grains during their mutual Coulomb collisions. The energy source for the acceleration are the irreversible plasma fluxes continuously absorbed by grains. In particular, this mechanism of charge-fluctuation-induced acceleration affects the rate of grain coagulation and shattering of the population of small grains.

  19. Acceleration of particles in imbalanced magnetohydrodynamic turbulence.

    Science.gov (United States)

    Teaca, Bogdan; Weidl, Martin S; Jenko, Frank; Schlickeiser, Reinhard

    2014-08-01

    The present work investigates the acceleration of test particles, relevant to the solar-wind problem, in balanced and imbalanced magnetohydrodynamic turbulence (terms referring here to turbulent states possessing zero and nonzero cross helicity, respectively). These turbulent states, obtained numerically by prescribing the injection rates for the ideal invariants, are evolved dynamically with the particles. While the energy spectrum for balanced and imbalanced states is known, the impact made on particle heating is a matter of debate, with different considerations giving different results. By performing direct numerical simulations, resonant and nonresonant particle accelerations are automatically considered and the correct turbulent phases are taken into account. For imbalanced turbulence, it is found that the acceleration rate of charged particles is reduced and the heating rate diminished. This behavior is independent of the particle gyroradius, although particles that have a stronger adiabatic motion (smaller gyroradius) tend to experience a larger heating.

  20. Acceleration of Particles in Imbalanced Magnetohydrodynamic Turbulence

    CERN Document Server

    Teaca, Bogdan; Jenko, Frank; Schlickeiser, Reinhard

    2014-01-01

    The present work investigates the acceleration of test particles in balanced and imbalanced Alfv\\'{e}nic turbulence, relevant to the solar-wind problem. These turbulent states, obtained numerically by prescribing the injection rates for the ideal invariants, are evolved dynamically with the particles. While the energy spectrum for balanced and imbalanced states is known, the impact made on particle heating is a matter of debate, with different considerations giving different results. By performing direct numerical simulations, resonant and non-resonant particle accelerations are automatically considered and the correct turbulent phases are taken into account. For imbalanced turbulence, it is found that the acceleration rate of charged particles is reduced and the heating rate diminished. This behaviour is independent of the particle gyroradius, although particles that have a stronger adiabatic motion (smaller gyroradius) tend to experience a larger heating.

  1. Particle acceleration mechanisms

    CERN Document Server

    Petrosyan, V

    2008-01-01

    We review the possible mechanisms for production of non-thermal electrons which are responsible for non-thermal radiation in clusters of galaxies. Our primary focus is on non-thermal Bremsstrahlung and inverse Compton scattering, that produce hard X-ray emission. We briefly review acceleration mechanisms and point out that in most astrophysical situations, and in particular for the intracluster medium, shocks, turbulence and plasma waves play a crucial role. We consider two scenarios for production of non-thermal radiation. The first is hard X-ray emission due to non-thermal Bremsstrahlung by nonrelativistic particles. Non-thermal tails are produced by accelerating electrons from the background plasma with an initial Maxwellian distribution. However, these tails are accompanied by significant heating and they are present for a short time of <10^6 yr, which is also the time that the tail will be thermalised. Such non-thermal tails, even if possible, can only explain the hard X-ray but not the radio emission...

  2. Field calculations, single-particle tracking, and beam dynamics with space charge in the electron lens for the Fermilab Integrable Optics Test Accelerator

    CERN Document Server

    Noll, Daniel

    2015-01-01

    An electron lens is planned for the Fermilab Integrable Optics Test Accelerator as a nonlinear element for integrable dynamics, as an electron cooler, and as an electron trap to study space-charge compensation in rings. We present the main design principles and constraints for nonlinear integrable optics. A magnetic configuration of the solenoids and of the toroidal section is laid out. Single-particle tracking is used to optimize the electron path. Electron beam dynamics at high intensity is calculated with a particle-in-cell code to estimate current limits, profile distortions, and the effects on the circulating beam. In the conclusions, we summarize the main findings and list directions for further work.

  3. Charged fermions tunneling from accelerating and rotating black holes

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Mudassar; Saifullah, K., E-mail: mudassir051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)

    2011-03-01

    We study Hawking radiation of charged fermions from accelerating and rotating black holes with electric and magnetic charges. We calculate the tunneling probabilities of incoming and outgoing fermionic particles and find the Hawking temperature of these black holes. We also provide an explicit expression of the classical action for the massive and massless particles in the background of these black holes.

  4. Particle accelerator; the Universe machine

    CERN Multimedia

    Yurkewicz, Katie

    2008-01-01

    "In summer 2008, scientists will switch on one of the largest machines in the world to search for the smallest of particle. CERN's Large Hadron Collider particle accelerator has the potential to chagne our understanding of the Universe."

  5. Radiation from moving charged particles with spin

    Energy Technology Data Exchange (ETDEWEB)

    Luccio, A.

    1992-10-05

    The theory of radiation emitted by a charged particle with spin in relativistic motion in an external magnetic field is reviewed. Approximate expressions suitable numerical computation, in far and near field, are derived. In particular, the case of the passage of a particle accelerator beam through an undulator is considered. It is shown that observation of the spectrum of the emitted radiation, in its two states of polarization, can be used not only for beam diagnostics, but also to measure the spin state of the accelerated particles. Undulator radiation is compared with Compton scattering of laser light by the particle beam. Examples for high energy electron and proton colliders are presented.

  6. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

    An exhibition of plastic arts and two evenings of performances by sound and visual artists as part of CERN's 50th anniversary celebrations. Fifty candles for CERN, an international laboratory renowned for fundamental research, is a cause for celebration. Since March this year, Geneva and neighbouring parts of France have been the venues for a wealth of small and large-scale events, which will continue until November. Given CERN's location in the commune of Meyrin, the ForuMeyrin is hosting exhibitions of plastic arts and performances entitled: Accelerated Particles. Several works will be exhibited and performed in two 'salons'. Salon des matières: An exhibition of plastic arts From Tues 12 October to Wed 3 November 2004 Tuesdays to Fridays: 16:00 to 19:00 Saturdays: 14:00 to 18:00 Exhibition open late on performance nights, entrance free Salon des particules: Musical and visual performances Tues 12 and Mon 25 October from 20:00 to 23:00 Preview evening for both events: Tues 12 October from 18:...

  7. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

    http://www.cern.ch/cern50/ An exhibition of plastic arts and two evenings of performances by sound and visual artists as part of CERN's fiftieth anniversary celebrations. The fiftieth anniversary of a world famous organization like CERN, an international laboratory specializing in fundamental research, is a cause for celebration. Since March this year, Geneva and neighbouring parts of France have been the venues for a wealth of small and large-scale events, which will continue until November. Given CERN's location in the commune of Meyrin, the ForuMeyrin is hosting two "salons" consisting of an exhibition of plastic arts and evenings of music and visual arts performances with the collective title of "Accelerated Particles". Several works will be exhibited and performed. Salon des matières: An exhibition of plastic arts Until Wednesday 3 November 2004. Tuesdays to Fridays: 4.00 p.m. to 7.00 p.m. Saturdays: 2.00 p.m. to 6.00 p.m. Doors open late on the evening of the performances. Salon des ...

  8. A novel adaptive time stepping variant of the Boris–Buneman integrator for the simulation of particle accelerators with space charge

    Energy Technology Data Exchange (ETDEWEB)

    Toggweiler, Matthias, E-mail: rmf7@m4t.ch [ETH Zürich, Computer Science Department, Universitätsstrasse 6, 8092 Zürich (Switzerland); Paul Scherrer Institute, CH-5234 Villigen (Switzerland); MIT, Department of Physics, 77 Massachusetts Avenue, MA 02139 (United States); Adelmann, Andreas, E-mail: andreas.adelmann@psi.ch [Paul Scherrer Institute, CH-5234 Villigen (Switzerland); Arbenz, Peter, E-mail: arbenz@inf.ethz.ch [ETH Zürich, Computer Science Department, Universitätsstrasse 6, 8092 Zürich (Switzerland); Yang, Jianjun, E-mail: jianjun.yang@psi.ch [Paul Scherrer Institute, CH-5234 Villigen (Switzerland); China Institute of Atomic Energy, Beijing, 102413 (China)

    2014-09-15

    We show that adaptive time stepping in particle accelerator simulation is an enhancement for certain problems. The new algorithm has been implemented in the OPAL (Object Oriented Parallel Accelerator Library) framework. The idea is to adjust the frequency of costly self-field calculations, which are needed to model Coulomb interaction (space charge) effects. In analogy to a Kepler orbit simulation that requires a higher time step resolution at the close encounter, we propose to choose the time step based on the magnitude of the space charge forces. Inspired by geometric integration techniques, our algorithm chooses the time step proportional to a function of the current phase space state instead of calculating a local error estimate like a conventional adaptive procedure. Building on recent work, a more profound argument is given on how exactly the time step should be chosen. An intermediate algorithm, initially built to allow a clearer analysis by introducing separate time steps for external field and self-field integration, turned out to be useful by its own, for a large class of problems.

  9. Nonlinear dynamics in particle accelerators

    CERN Document Server

    Dilão, Rui

    1996-01-01

    This book is an introductory course to accelerator physics at the level of graduate students. It has been written for a large audience which includes users of accelerator facilities, accelerator physicists and engineers, and undergraduates aiming to learn the basic principles of construction, operation and applications of accelerators.The new concepts of dynamical systems developed in the last twenty years give the theoretical setting to analyse the stability of particle beams in accelerator. In this book a common language to both accelerator physics and dynamical systems is integrated and dev

  10. Modeling and Analysis of Radio Frequency Structures Using AN Equivalent Circuit Methodology with Application to Charged Particle Accelerator RF Resonators

    Science.gov (United States)

    Vincent, John J.

    The delineation of analysis techniques for high power radio frequency resonators, used as a fundamental component of particle accelerators, receives little attention in the literature. This dissertation reviews, describes, and develops techniques for resolving a transmission line mode rf resonator into an approximate equivalent circuit. Specifically, it presents a toolbox of techniques used to model and represent rf structures. One technique develops models of transmission lines with varying characteristic impedance (referred to as non-uniform) using multiple series connected circuits consisting of lumped elements and constant impedance transmission lines based on a conserved energy approach. This technique is tested for exponentially tapered and linearly tapered quarter-wave resonators. Another technique developed, maps transmission lines with arbitrary cross-sections (referred to as nonstandard) to a standard structure that preserves the characteristic impedance and loss properties of the original line. The techniques developed are applied to the analysis of the complex K1200 Superconducting Cyclotron rf resonators at the National Superconducting Cyclotron Laboratory (NSCL). The results predicted from the model are compared to measurements. The K1200 rf resonators are tunable over the frequency range of 9.5 to 27 MHz with tuning stems that vary from 300 cm to 11 cm respectively. The resonators are operated in the continuos wave (cw) mode and sustain peak voltages of up to 180 kV requiring drive power of up to 250 kW. Using the techniques developed, the resonant frequency versus tuning stem position was predicted to within a positioning error that varied from 1 to 3.5 cm over the tuning range of 9.5 to 27 Mhz. The discrepancy between model predictions and the experimental data for the resonator power dissipation is postulated to be due to high surface resistance in regions where the rf surfaces were heavily worked or welded. After adjusting the surface resistance

  11. Studying Charged Particle Optics: An Undergraduate Course

    Science.gov (United States)

    Ovalle, V.; Otomar, D. R.; Pereira, J. M.; Ferreira, N.; Pinho, R. R.; Santos A. C. F.

    2008-01-01

    This paper describes some computer-based activities to bring the study of charged particle optics to undergraduate students, to be performed as a part of a one-semester accelerator-based experimental course. The computational simulations were carried out using the commercially available SIMION program. The performance parameters, such as the focal…

  12. Fast ion mass spectrometry and charged particle spectrography investigations of transverse ion acceleration and beam-plasma interactions

    Science.gov (United States)

    Gibson, W. C.; Tomlinson, W. M.; Marshall, J. A.

    1987-01-01

    Ion acceleration transverse to the magnetic field in the topside ionosphere was investigated. Transverse acceleration is believed to be responsible for the upward-moving conical ion distributions commonly observed along auroral field lines at altitudes from several hundred to several thousand kilometers. Of primary concern in this investigation is the extent of these conic events in space and time. Theoretical predictions indicate very rapid initial heating rates, depending on the ion species. These same theories predict that the events will occur within a narrow vertical region of only a few hundred kilometers. Thus an instrument with very high spatial and temporal resolution was required; further, since different heating rates were predicted for different ions, it was necessary to obtain composition as well as velocity space distributions. The fast ion mass spectrometer (FIMS) was designed to meet these criteria. This instrument and its operation is discussed.

  13. Thermophoresis of charged colloidal particles.

    Science.gov (United States)

    Fayolle, Sébastien; Bickel, Thomas; Würger, Alois

    2008-04-01

    Thermally induced particle flow in a charged colloidal suspension is studied in a fluid-mechanical approach. The force density acting on the charged boundary layer is derived in detail. From Stokes' equation with no-slip boundary conditions at the particle surface, we obtain the particle drift velocity and the thermophoretic transport coefficients. The results are discussed in view of previous work and available experimental data.

  14. Thermophoresis of charged colloidal particles

    OpenAIRE

    Fayolle, Sébastien; Bickel, Thomas; Würger, Alois

    2008-01-01

    International audience; Thermally induced particle flow in a charged colloidal suspension is studied in a fluid-mechanical approach. The force density acting on the charged boundary layer is derived in detail. From Stokes' equation with no-slip boundary conditions at the particle surface, we obtain the particle drift velocity and the thermophoretic transport coefficients. The results are discussed in view of previous work and available experimental data.

  15. Particle acceleration around SNR shocks

    Energy Technology Data Exchange (ETDEWEB)

    Morlino, G., E-mail: morlino@arcetri.astro.it [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5, 50125 Firenze (Italy)

    2013-08-21

    We review the basic features of particle acceleration theory around collisionless shocks in supernova remnants (SNRs). We show how non-linear effects induced by the back reaction of accelerated particles onto the shock dynamics are of paramount importance to support the hipotesys that SNRs are the factories of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of magnetic field amplification and the presence of neutrals in the circumstellar environment. Special attention will be devoted to observational consequences of non-linear effects on the multi-wavelength spectrum of SNRs, with emphasis on X-ray and gamma-ray emission. Finally we also discuss how Balmer lines, detected from several young SNRs, can be used to estimate the shock dynamical properties and the efficiency of CR acceleration.

  16. Particle acceleration around SNR shocks

    CERN Document Server

    Morlino, Giovanni

    2012-01-01

    We review the basic features of particle acceleration theory around collisionless shocks in supernova remnants (SNRs). We show how non linear effects induced by the back reaction of accelerated particles onto the shock dynamics are of paramount importance to support the hipotesys that SNRs are the factories of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of magnetic field amplification and the presence of neutrals in the circumstellar environment. Special attention will be devoted to observational consequences of non linear effects on the multi-wavelength spectrum of SNRs, with emphasis on X-ray and gamma-ray emission. Finally we also discuss how Balmer lines, detected from several young SNRs, can be used to estimate the shock dynamical properties and the efficiency of CR acceleration.

  17. Cooled particle accelerator target

    Science.gov (United States)

    Degtiarenko, Pavel V.

    2005-06-14

    A novel particle beam target comprising: a rotating target disc mounted on a retainer and thermally coupled to a first array of spaced-apart parallel plate fins that extend radially inwardly from the retainer and mesh without physical contact with a second array of spaced-apart parallel plate fins that extend radially outwardly from and are thermally coupled to a cooling mechanism capable of removing heat from said second array of spaced-apart fins and located within the first array of spaced-apart parallel fins. Radiant thermal exchange between the two arrays of parallel plate fins provides removal of heat from the rotating disc. A method of cooling the rotating target is also described.

  18. Electrooptical Detection of Charged Particles

    CERN Document Server

    Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R; Lazarus, D M; Magurno, B; Nikas, D; Ozben, C; Srinivasan-Rao, T; Tsang, Thomas

    2000-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds promise for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

  19. Coaxial charged particle energy analyzer

    Science.gov (United States)

    Kelly, Michael A. (Inventor); Bryson, III, Charles E. (Inventor); Wu, Warren (Inventor)

    2011-01-01

    A non-dispersive electrostatic energy analyzer for electrons and other charged particles having a generally coaxial structure of a sequentially arranged sections of an electrostatic lens to focus the beam through an iris and preferably including an ellipsoidally shaped input grid for collimating a wide acceptance beam from a charged-particle source, an electrostatic high-pass filter including a planar exit grid, and an electrostatic low-pass filter. The low-pass filter is configured to reflect low-energy particles back towards a charged particle detector located within the low-pass filter. Each section comprises multiple tubular or conical electrodes arranged about the central axis. The voltages on the lens are scanned to place a selected energy band of the accepted beam at a selected energy at the iris. Voltages on the high-pass and low-pass filters remain substantially fixed during the scan.

  20. Studying charged particle optics: an undergraduate course

    Energy Technology Data Exchange (ETDEWEB)

    Ovalle, V [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n0. Gragoata, Niteroi, 24210-346 Rio de Janeiro (Brazil); Otomar, D R [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n0. Gragoata, Niteroi, 24210-346 Rio de Janeiro (Brazil); Pereira, J M [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro (Brazil); Ferreira, N [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n0. Gragoata, Niteroi, 24210-346 Rio de Janeiro (Brazil); Pinho, R R [Departamento de Fisica-ICE, Universidade Federal de Juiz de Fora, Campus Universitario, 36036-900, Juiz de Fora, MG (Brazil); Santos, A C F [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro (Brazil)

    2008-03-12

    This paper describes some computer-based activities to bring the study of charged particle optics to undergraduate students, to be performed as a part of a one-semester accelerator-based experimental course. The computational simulations were carried out using the commercially available SIMION program. The performance parameters, such as the focal length and P-Q curves are obtained. The three-electrode einzel lens is exemplified here as a study case.

  1. Computer modeling of test particle acceleration at oblique shocks

    Science.gov (United States)

    Decker, Robert B.

    1988-01-01

    The present evaluation of the basic techniques and illustrative results of charged particle-modeling numerical codes suitable for particle acceleration at oblique, fast-mode collisionless shocks emphasizes the treatment of ions as test particles, calculating particle dynamics through numerical integration along exact phase-space orbits. Attention is given to the acceleration of particles at planar, infinitessimally thin shocks, as well as to plasma simulations in which low-energy ions are injected and accelerated at quasi-perpendicular shocks with internal structure.

  2. Contributions to the 1999 particle accelerator conference

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, M. [Laboratoire de l' Accelerateur Lineaire, 91 - Orsay (France); Fartoukh, S.; Jablonka, M.; Joly, J.M.; Lalot, M.; Magne, C.; Napoly, O. [CEA/Saclay, 91 - Gif sur Yvette (France); Baboi, N.; Schreiber, S.; Simrock, S.; Weise, H. [DESY, Hamburg (Germany)

    2000-06-01

    This document puts together the 10 contributions of the laboratory to the 1999 particle accelerator conference. The titles of the papers are: 1) Evidence for a strongly coupled dipole mode with insufficient damping in the first accelerating module of the TESLA test facility (TTF); 2) An alternative scheme for stiffening superconducting RF cavities by plasma spraying; 3) A laser triggered electron source for pulsed radiolysis; 4) A cure for the energy spread increasing related bunch lengthening in electron storage rings; 5) Single bunch longitudinal instabilities in proton storage rings; 6) Analytical investigation on the halo formation in space charge dominated beams; 7) Analytical investigation on the dynamic apertures of circular accelerators; 8) The intrinsic upper limit to the beam energy of an electron-positron circular collider; 9) Coaxial disc windows for a high power superconducting cavity input coupler; and 10) RF pulsed tests on 3 GHz niobium cavities.

  3. Particle Accelerators for PET radionuclides

    DEFF Research Database (Denmark)

    Jensen, Mikael

    2012-01-01

    The requirements set for particle accelerators for production of radioactive isotopes for PET can easily be derived from first principles. The simple general need is for proton beams with energy in the region 10–20 MeV and current 20–100 microAmps. This is most reliably and cost-effectively achie......The requirements set for particle accelerators for production of radioactive isotopes for PET can easily be derived from first principles. The simple general need is for proton beams with energy in the region 10–20 MeV and current 20–100 microAmps. This is most reliably and cost...... different manufacturers will be discussed the light of what is actually needed for a given PET site operation. Alternatives to the conventional cyclotron have been proposed and tested but have at present very limited use. These alternatives will be discussed, as well as the future possibilities of supplying...

  4. Minimization of power consumption during charging of superconducting accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, Anirban Krishna, E-mail: anirban.bhattacharyya@physics.uu.se; Ziemann, Volker; Ruber, Roger; Goryashko, Vitaliy

    2015-11-21

    The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Energies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

  5. Minimization of power consumption during charging of superconducting accelerating cavities

    Science.gov (United States)

    Bhattacharyya, Anirban Krishna; Ziemann, Volker; Ruber, Roger; Goryashko, Vitaliy

    2015-11-01

    The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Energies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

  6. Development of a Charged Particle Microbeam for Targeted and Single Particle Subcellular Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, Jacquelyn C.

    2004-03-12

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube.

  7. Illusory flow in radiation from accelerating charge

    Energy Technology Data Exchange (ETDEWEB)

    Biro, Tamas S.; Szendi, Zsuzsanna [RMI, WIGNER Research Centre for Physics, Budapest (Hungary); Schram, Zsolt [University of Debrecen, Department of Theoretical Physics, Debrecen (Hungary); MTA-DE Particle Physics Research Group, Debrecen (Hungary)

    2014-03-15

    In this paper we analyze the classical electromagnetic radiation of an accelerating point charge moving on a straight line trajectory. Depending on the duration of accelerations, rapidity distributions of photons emerge, resembling the ones obtained in the framework of hydrodynamical models by Landau or Bjorken. Detectable differences between our approach and spectra obtained from hydrodynamical models occur at high transverse momenta due to classical wave interference phenomena included in our model. (orig.)

  8. Illusory Flow in Radiation from Accelerating Charge

    CERN Document Server

    Biro, Tamas S; Schram, Zsolt

    2014-01-01

    In this paper we analyze the classical electromagnetic radiation of an accelerating point charge moving on a straight line trajectory. Depending on the duration of accelerations, rapidity distributions of photons emerge, resembling the ones obtained in the framework of hydrodynamical models by Landau or Bjorken. Detectable differences between our approach and spectra obtained from hydrodynamical models occur at high transverse momenta and are due to interference.

  9. Charge Diagnostics for Laser Plasma Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K.; Gonsalves, A. J.; Lin, C.; Sokollik, T.; Smith, A.; Rodgers, D.; Donahue, R.; Bryne, W.; Leemans, W. P.

    2010-06-01

    The electron energy dependence of a scintillating screen (Lanex Fast) was studied with sub-nanosecond electron beams ranging from 106 MeV to 1522 MeV at the Lawrence Berkeley National Laboratory Advanced Light Source (ALS) synchrotron booster accelerator. The sensitivity of the Lanex Fast decreased by 1percent per 100 MeV increase of the energy. The linear response of the screen against the charge was verified with charge density and intensity up to 160 pC/mm2 and 0.4 pC/ps/mm2, respectively. For electron beams from the laser plasma accelerator, a comprehensive study of charge diagnostics has been performed using a Lanex screen, an integrating current transformer, and an activation based measurement. The charge measured by each diagnostic was found to be within +/-10 percent.

  10. Magnetic guidance of charged particles

    Directory of Open Access Journals (Sweden)

    Dirk Dubbers

    2015-09-01

    Full Text Available Many experiments and devices in physics use static magnetic fields to guide charged particles from a source onto a detector, and we ask the innocent question: What is the distribution of particle intensity over the detector surface? One should think that the solution to this seemingly simple problem is well known. We show that, even for uniform guide fields, this is not the case, and we present analytical point spread functions (PSF for magnetic transport that deviate strongly from previous results. The “magnetic” PSF shows unexpected singularities, which were recently also observed experimentally, and which make detector response very sensitive to minute changes of position, field amplitude, or particle energy. In the field of low-energy particle physics, these singularities may become a source of error in modern high precision experiments, or may be used for instrument tests.

  11. Geometrical charged-particle optics

    CERN Document Server

    Rose, Harald H

    2009-01-01

    This reference monograph covers all theoretical aspects of modern geometrical charged-particle optics. It is intended as a guide for researchers, who are involved in the design of electron optical instruments and beam-guiding systems for charged particles, and as a tutorial for graduate students seeking a comprehensive treatment. Procedures for calculating the properties of systems with arbitrarily curved axes are outlined in detail and methods are discussed for designing and optimizing special components such as aberration correctors, spectrometers, energy filters, monochromators, ion traps, electron mirrors and cathode lenses. Also addressed is the design of novel electron optical components enabling sub-Angstroem spatial resolution and sub-0.1eV energy resolution. Relativistic motion and spin precession of the electron is treated in a concise way by employing a covariant five-dimensional procedure.

  12. Geometrical charged-particle optics

    CERN Document Server

    Rose, Harald

    2012-01-01

    This second edition is an extended version of the first edition of Geometrical Charged-Particle Optics. The updated reference monograph is intended as a guide for researchers and graduate students who are seeking a comprehensive treatment of the design of instruments and beam-guiding systems of charged particles and their propagation in electromagnetic fields. Wave aspects are included in this edition for explaining electron holography, the Aharanov-Bohm effect and the resolution of electron microscopes limited by diffraction. Several methods for calculating the electromagnetic field are presented and procedures are outlined for calculating the properties of systems with arbitrarily curved axis. Detailed methods are presented for designing and optimizing special components such as aberration correctors, spectrometers, energy filters monochromators, ion traps, electron mirrors and cathode lenses. In particular, the optics of rotationally symmetric lenses, quadrupoles, and systems composed of these elements are...

  13. Charged particles in Titan's ionosphere

    Science.gov (United States)

    Tripathi, Sachchida

    2010-05-01

    Charged particles in Titan's ionosphere Marykutty Michael1, Sachchida Nand Tripathi1,2,3, Pratima Arya1 1Indian Institute of Technology Kanpur 2Oak Ridge Associated Universities 3NASA Goddard Space Flight Center Observations by two instruments onboard the Cassini spacecraft, Ion Neutral Mass Spectrometer (INMS) and CAssini Plasma Spectrometer (CAPS), revealed the existence of heavy hydrocarbon and nitrile species with masses of several thousand atomic mass units at altitudes of 950 - 1400 km in the atmosphere of Titan (Waite et al., 2007; Crary et al., 2009). Though these particles were believed to be molecules, they are most likely aerosols formed by the clumping of smaller molecules (Waite et al., 2009). These particles were estimated to have a density of 10-3 kg m-3 and a size of up to 256 nm. The existence of very heavy ions has also been observed by the CAPS components with a mass by charge ratio of up to 10000 (Coates et al., 2007, 2009; Sittler et al., 2009). The goal of this paper is to find out whether the so called heavy ions (or charged particles) are generated by the charge transfer of ions and electrons to the particles. The charging of these particles has been studied by using the charge balance equations that include positive ions, negative ions, electrons, neutral and charged particles. Information on the most abundant ion clusters are obtained from Vuitton et al., (2009) and Wilson and Atreya, (2004). Mass by charge ratio thus calculated will be compared with those observed by Coates et al. (2007). References: Coates AJ, et al., Discovery of heavy negative ions in Titan's ionosphere, Geophys. Res. Lett., 34:L22103, 2007. Coates AJ, et al., Heavy negative ions in titan's ionosphere: altitude and latitude dependence. Planet. Space Sci., doi:10.1016/j.pss.2009.05.009, 2009. Crary F.J., et al., Heavy ions, temperatures and winds in titan's ionosphere: Combined cassini caps and inms observations. Planet. Space Sci., doi:10.1016/j.pss.2009.09.006, 2009

  14. Solar Particle Acceleration at Reconnecting 3D Null Points

    CERN Document Server

    Stanier, Adam J; Dalla, Silvia

    2012-01-01

    Context: The strong electric fields associated with magnetic reconnection in solar flares are a plausible mechanism to accelerate populations of high energy, non-thermal particles. One such reconnection scenario occurs at a 3D magnetic null point, where global plasma flows give rise to strong currents in the spine axis or fan plane. Aims: To understand the mechanism of charged particle energy gain in both the external drift region and the diffusion region associated with 3D magnetic reconnection. In doing so we evaluate the efficiency of resistive spine and fan models for particle acceleration, and find possible observables for each. Method: We use a full orbit test particle approach to study proton trajectories within electromagnetic fields that are exact solutions to the steady and incompressible magnetohydrodynamic equations. We study single particle trajectories and find energy spectra from many particle simulations. The scaling properties of the accelerated particles with respect to field and plasma para...

  15. A highly segmented. Delta. E-time-of-flight wall as forward detector of the 4. pi. -system for charged particles at the SIS/ESR accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Gobbi, A.; Augustinski, G.; Bock, R.; Charity, R.J.; Fan, Z.G.; Freifelder, R.; Grigorian, Y.; Hildenbrand, K.D.; Jeong, S.C.; Marquardt, M.; Reisdorf, W.; Schuell, D.; Sodan, U.; Tanaka, M.H.; Teh, K.M.; Weinert, J.; Wessels, J.P. (Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)); Alard, J.P.; Bastid, N.; Boussange, S.; Crouau, M.; Daudon, F.; Dupieux, P.; Fayard, C.; Fraysse, L.; Jorio, M.; Mayade, S.; Mo

    1992-05-01

    At the SIS/ESR accelerator facility at GSI in Darmstadt the 4{pi}-detector system FOPI is under construction at present. It is designed for the investigation of central collisions of heavy ions in the energy range up to 2xA GeV. As phase I of this detector a forward wall has been built and used in various experiments. It comprises a total number of 764 scintillators with an additional shell of 188 thin {Delta}E-detectors in front of it and covers the full azimuth of the polar angles from 1{sup 0} to 30{sup 0}. The velocity and the nuclear charge of the fragments are determined by a combined time of flight and {Delta}E measurement. (orig.).

  16. RFQ device for accelerating particles

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Delayen, J.R.

    1995-06-06

    A superconducting radio frequency quadrupole (RFQ) device includes four spaced elongated, linear, tubular rods disposed parallel to a charged particle beam axis, with each rod supported by two spaced tubular posts oriented radially with respect to the beam axis. The rod and post geometry of the device has four-fold rotation symmetry, lowers the frequency of the quadrupole mode below that of the dipole mode, and provides large dipole-quadrupole mode isolation to accommodate a range of mechanical tolerances. The simplicity of the geometry of the structure, which can be formed by joining eight simple T-sections, provides a high degree of mechanical stability, is insensitive to mechanical displacement, and is particularly adapted for fabrication with superconducting materials such as niobium. 5 figs.

  17. RFQ device for accelerating particles

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, Kenneth W. (Park Ridge, IL); Delayen, Jean R. (Naperville, IL)

    1995-01-01

    A superconducting radio frequency quadrupole (RFQ) device includes four spaced elongated, linear, tubular rods disposed parallel to a charged particle beam axis, with each rod supported by two spaced tubular posts oriented radially with respect to the beam axis. The rod and post geometry of the device has four-fold rotation symmetry, lowers the frequency of the quadrupole mode below that of the dipole mode, and provides large dipole-quadrupole mode isolation to accommodate a range of mechanical tolerances. The simplicity of the geometry of the structure, which can be formed by joining eight simple T-sections, provides a high degree of mechanical stability, is insensitive to mechanical displacement, and is particularly adapted for fabrication with superconducting materials such as niobium.

  18. Neural computation and particle accelerators research, technology and applications

    CERN Document Server

    D'Arras, Horace

    2010-01-01

    This book discusses neural computation, a network or circuit of biological neurons and relatedly, particle accelerators, a scientific instrument which accelerates charged particles such as protons, electrons and deuterons. Accelerators have a very broad range of applications in many industrial fields, from high energy physics to medical isotope production. Nuclear technology is one of the fields discussed in this book. The development that has been reached by particle accelerators in energy and particle intensity has opened the possibility to a wide number of new applications in nuclear technology. This book reviews the applications in the nuclear energy field and the design features of high power neutron sources are explained. Surface treatments of niobium flat samples and superconducting radio frequency cavities by a new technique called gas cluster ion beam are also studied in detail, as well as the process of electropolishing. Furthermore, magnetic devises such as solenoids, dipoles and undulators, which ...

  19. Particle acceleration at a reconnecting magnetic separator

    CERN Document Server

    Threlfall, J; Parnell, C E; Oskoui, S Eradat

    2014-01-01

    While the exact acceleration mechanism of energetic particles during solar flares is (as yet) unknown, magnetic reconnection plays a key role both in the release of stored magnetic energy of the solar corona and the magnetic restructuring during a flare. Recent work has shown that special field lines, called separators, are common sites of reconnection in 3D numerical experiments. To date, 3D separator reconnection sites have received little attention as particle accelerators. We investigate the effectiveness of separator reconnection as a particle acceleration mechanism for electrons and protons. We study the particle acceleration using a relativistic guiding-centre particle code in a time-dependent kinematic model of magnetic reconnection at a separator. The effect upon particle behaviour of initial position, pitch angle and initial kinetic energy are examined in detail, both for specific (single) particle examples and for large distributions of initial conditions. The separator reconnection model contains ...

  20. Charge of dust particles in a particle chain

    CERN Document Server

    Yousefi, Razieh; Matthews, Lorin Swint; Hyde, Truell W

    2016-01-01

    Charged dust particles form structures which are extended in the vertical direction in the electrode sheath of a rf discharge when confined within a glass box. The charge on each particle as a function of height varies due to the changing plasma conditions and the wakefield of upstream particles. Here an analysis of the equilibrium state of chains of varying number of particles is analyzed to determine the charge on each particle within a vertically extended chain as well as the magnitude of the positive wakefield charge.

  1. Trans-Relativistic Particle Acceleration in Astrophysical Plasmas

    Science.gov (United States)

    Becker, Peter A.; Subramanian, P.

    2014-01-01

    Trans-relativistic particle acceleration due to Fermi interactions between charged particles and MHD waves helps to power the observed high-energy emission in AGN transients and solar flares. The trans-relativistic acceleration process is challenging to treat analytically due to the complicated momentum dependence of the momentum diffusion coefficient. For this reason, most existing analytical treatments of particle acceleration assume that the injected seed particles are already relativistic, and therefore they are not suited to study trans-relativistic acceleration. The lack of an analytical model has forced workers to rely on numerical simulations to obtain particle spectra describing the trans-relativistic case. In this work we present the first analytical solution to the global, trans-relativistic problem describing the acceleration of seed particles due to hard-sphere collisions with MHD waves. The new results include the exact solution for the steady-state Green's function resulting from the continual injection of monoenergetic seed particles with an arbitrary energy. We also introduce an approximate treatment of the trans-relativistic acceleration process based on a hybrid form for the momentum diffusion coefficient, given by the sum of the two asymptotic forms. We refer to this process as "quasi hard-sphere scattering." The main advantage of the hybrid approximation is that it allows the extension of the physical model to include (i) the effects of synchrotron and inverse-Compton losses and (ii) time dependence. The new analytical results can be used to model the trans-relativistic acceleration of particles in AGN and solar environments, and can also be used to compute the spectra of the associated synchrotron and inverse-Compton emission. Applications of both types are discussed. We highlight (i) relativistic ion acceleration in black hole accretion coronae, and (ii) the production of gyrosynchrotron microwave emission due to relativistic electron

  2. Stochastic particle acceleration in multiple magnetic islands during reconnection.

    Science.gov (United States)

    Hoshino, Masahiro

    2012-03-30

    A nonthermal particle acceleration mechanism involving the interaction of a charged particle with multiple magnetic islands is proposed. The original Fermi acceleration model, which assumes randomly distributed magnetic clouds moving at random velocity V(c) in the interstellar medium, is known to be of second-order acceleration of O(V(c)/c)(2) owing to the combination of head-on and head-tail collisions. In this Letter, we reconsider the original Fermi model by introducing multiple magnetic islands during reconnection instead of magnetic clouds. We discuss that the energetic particles have a tendency to be distributed outside the magnetic islands, and they mainly interact with reconnection outflow jets. As a result, the acceleration efficiency becomes first order of O(V(A)/c), where V(A) and c are the Alfvén velocity and the speed of light, respectively.

  3. 3D Simulations of Space Charge Effects in Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Adelmann, A

    2002-10-01

    For the first time, it is possible to calculate the complicated three-dimensional proton accelerator structures at the Paul Scherrer Institut (PSI). Under consideration are external and self effects, arising from guiding and space-charge forces. This thesis has as its theme the design, implementation and validation of a tracking program for charged particles in accelerator structures. This work form part of the discipline of Computational Science and Engineering (CSE), more specifically in computational accelerator modelling. The physical model is based on the collisionless Vlasov-Maxwell theory, justified by the low density ({approx} 10{sup 9} protons/cm{sup 3}) of the beam and of the residual gas. The probability of large angle scattering between the protons and the residual gas is then sufficiently low, as can be estimated by considering the mean free path and the total distance a particle travels in the accelerator structure. (author)

  4. Charged particle beam scanning using deformed high gradient insulator

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu -Jiuan

    2015-10-06

    Devices and methods are provided to allow rapid deflection of a charged particle beam. The disclosed devices can, for example, be used as part of a hadron therapy system to allow scanning of a target area within a patient's body. The disclosed charged particle beam deflectors include a dielectric wall accelerator (DWA) with a hollow center and a dielectric wall that is substantially parallel to a z-axis that runs through the hollow center. The dielectric wall includes one or more deformed high gradient insulators (HGIs) that are configured to produce an electric field with an component in a direction perpendicular to the z-axis. A control component is also provided to establish the electric field component in the direction perpendicular to the z-axis and to control deflection of a charged particle beam in the direction perpendicular to the z-axis as the charged particle beam travels through the hollow center of the DWA.

  5. Sources for charged particles; Les sources de particules chargees

    Energy Technology Data Exchange (ETDEWEB)

    Arianer, J.

    1997-09-01

    This document is a basic course on charged particle sources for post-graduate students and thematic schools on large facilities and accelerator physics. A simple but precise description of the creation and the emission of charged particles is presented. This course relies on every year upgraded reference documents. Following relevant topics are considered: electronic emission processes, technological and practical considerations on electron guns, positron sources, production of neutral atoms, ionization, plasma and discharge, different types of positive and negative ion sources, polarized particle sources, materials for the construction of ion sources, low energy beam production and transport. (N.T.).

  6. Nonlinear Particle Acceleration and Thermal Particles in GRB Afterglows

    Science.gov (United States)

    Warren, Donald C.; Ellison, Donald C.; Barkov, Maxim V.; Nagataki, Shigehiro

    2017-02-01

    The standard model for GRB afterglow emission treats the accelerated electron population as a simple power law, N(E)\\propto {E}-p for p≳ 2. However, in standard Fermi shock acceleration, a substantial fraction of the swept-up particles do not enter the acceleration process at all. Additionally, if acceleration is efficient, then the nonlinear back-reaction of accelerated particles on the shock structure modifies the shape of the nonthermal tail of the particle spectra. Both of these modifications to the standard synchrotron afterglow impact the luminosity, spectra, and temporal variation of the afterglow. To examine the effects of including thermal particles and nonlinear particle acceleration on afterglow emission, we follow a hydrodynamical model for an afterglow jet and simulate acceleration at numerous points during the evolution. When thermal particles are included, we find that the electron population is at no time well fitted by a single power law, though the highest-energy electrons are; if the acceleration is efficient, then the power-law region is even smaller. Our model predicts hard–soft–hard spectral evolution at X-ray energies, as well as an uncoupled X-ray and optical light curve. Additionally, we show that including emission from thermal particles has drastic effects (increases by factors of 100 and 30, respectively) on the observed flux at optical and GeV energies. This enhancement of GeV emission makes afterglow detections by future γ-ray observatories, such as CTA, very likely.

  7. Accelerator cavities as a probe of millicharged particles

    Energy Technology Data Exchange (ETDEWEB)

    Gies, H. [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik; Jaeckel, J.; Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2006-08-15

    We investigate Schwinger pair production of millicharged fermions in the strong electric field of cavities used for particle accelerators. Even without a direct detection mechanism at hand, millicharged particles, if they exist, contribute to the energy loss of the cavity and thus leave an imprint on the cavity's quality factor. Already conservative estimates substantially constrain the electric charge of these hypothetical particles; the resulting bounds are competitive with the currently best laboratory bounds which arise from experiments based on polarized laser light propagating in a magnetic field. We propose an experimental setup for measuring the electric current comprised of the millicharged particles produced in the cavity. (orig.)

  8. Acceleration and Particle Field Interactions of Cosmic Rays I: Formalism

    CERN Document Server

    Tawfik, A; Ghoneim, M T; Hady, A A

    2010-01-01

    The acceleration of cosmic rays is conjectured to be the output from various interactions with the electromagnetic fields in astrophysical bodies, like magnetic matter clumps, and from the well-known shock and stochastic Fermi mechanism. The latter apparently does not depend on the particle's charge, quantitatively. Therefore, the motion of the charged particle parallel to magnetic field $\\mathbf{B}$ and under the influence of the force $\\mathbf{F}$. is assumed to be composed in an acceleration by non-magnetic force $\\mathbf{F}_{\\parallel}$ and gyromotion along $\\mathbf{B}$, plus a drift in direction of $\\mathbf{F}_{\\perp}$. In this letter, the model and its formalism are introduced. Also various examples for drift and accelerating forces are studied.

  9. New mechanism of acceleration of particles by stellar black holes

    CERN Document Server

    Osmanov, Z

    2016-01-01

    In this paper we study efficiency of particle acceleration in the magnetospheres of stellar mass black holes. For this purpose we consider the linearized set of the Euler equation, continuity equation and Poisson equation respectively. After introducing the varying relativistic centrifugal force, we show that the charge separation undergoes the parametric instability, leading to generation of centrifugally excited Langmuir waves. It is shown that these waves, via the Langmuir collapse damp by means of the Landau damping, as a result energy transfers to particles accelerating them to energies of the order of $10^{16}$eV.

  10. Lauch of CERN particle accelerator delayed

    CERN Multimedia

    2007-01-01

    "Scientists seeking to uncover the secrets of the universe will have to wait a little longer after the CERN laboratory inSwitzerland yesterday confirmed a delay in tests of its massive new particle accelerator." (1 page)

  11. Global particle accelerator gets the big chill

    CERN Multimedia

    Sherriff, Lucy

    2004-01-01

    Scientists at an international symposium in Beijing have recommended that a new global particle accelerator should be based on "cold" or superconducting technology, bringing the construction of the multi-billion dollar facility one step closer to reality (½ page)

  12. Scintillation Detectors for Charged Particles and Photons

    CERN Document Server

    Lecoq, P

    2011-01-01

    Scintillation Detectors for Charged Particles and Photons in 'Charged Particle Detectors - Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Subsection '3.1.1 Scintillation Detectors for Charged Particles and Photons' of Section '3.1 Charged Particle Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.1.1 Scintillation Detectors for Charged Particles and Photons 3.1.1.1 Basic detector principles and scintillator requirements 3.1.1.1.1 Interaction of ionizing radiation with scintillator material 3.1.1.1.2 Important scint...

  13. Charge Exchange Losses and Stochastic Acceleration in the Solar Wind

    CERN Document Server

    Kenny, Ciaran

    2016-01-01

    Stochastic acceleration of particles under a pressure balance condition can accommodate the universal $p^{-5}$ spectra observed under many different conditions in the inner heliosphere. In this model, in order to avoid an infinite build up of particle pressure, a relationship between the momentum diffusion of particles and the adiabatic deceleration in the solar wind must exist. This constrains both the spatial and momentum diffusion coefficients and results in the $p^{-5}$ spectrum in the presence of adiabatic losses in the solar wind. However, this theory cannot explain the presence of such spectra beyond the termination shock, where adiabatic deceleration is negligible. To explain this apparent discrepancy, we include the effect of charge exchange losses, resulting in new forms of both the spatial and momentum diffusion coefficients that have not previously been considered. Assuming that the turbulence is of a large-scale compressible nature, we find that a balance between momentum diffusion and losses can...

  14. Superconducting Magnets for Particle Accelerators

    CERN Document Server

    Rossi, L

    2012-01-01

    Superconductivity has been the most influential technology in the field of accelerators in the last 30 years. Since the commissioning of the Tevatron, which demonstrated the use and operability of superconductivity on a large scale, superconducting magnets and rf cavities have been at the heart of all new large accelerators. Superconducting magnets have been the invariable choice for large colliders, as well as cyclotrons and large synchrotrons. In spite of the long history of success, superconductivity remains a difficult technology, requires adequate R&D and suitable preparation, and has a relatively high cost. Hence, it is not surprising that the development has also been marked by a few setbacks. This article is a review of the main superconducting accelerator magnet projects; it highlights the main characteristics and main achievements, and gives a perspective on the development of superconducting magnets for the future generation of very high energy colliders.

  15. Geometric integration for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Forest, Etienne [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2006-05-12

    This paper is a very personal view of the field of geometric integration in accelerator physics-a field where often work of the highest quality is buried in lost technical notes or even not published; one has only to think of Simon van der Meer Nobel prize work on stochastic cooling-unpublished in any refereed journal. So I reconstructed the relevant history of geometrical integration in accelerator physics as much as I could by talking to collaborators and using my own understanding of the field. The reader should not be too surprised if this account is somewhere between history, science and perhaps even fiction.

  16. Dynamics of neutral and charged aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Leppae, J.

    2012-07-01

    Atmospheric aerosol particles have various climate effects and adverse health effects, which both depend on the size and number concentration of the particles. Freshly-formed particles are not large enough to impact neither health nor climate and they are most susceptible to removal by collisions with larger pre-existing particles. Consequently, the knowledge of both the formation and the growth rate of particles are crucially important when assessing the health and climate effects of atmospheric new particle formation. The purpose of this thesis is to increase our knowledge of the dynamics of neutral and charged aerosol particles with a specific interest towards the particle growth rate and processes affecting the aerosol charging state. A new model, Ion-UHMA, which simulates the dynamics of neutral and charged particles, was developed for this purpose. Simple analytical formulae that can be used to estimate the growth rate due to various processes were derived and used to study the effects of charged particles on the growth rate. It was found that the growth rate of a freshly-formed particle population due to condensation and coagulation could be significantly increased when a considerable fraction of the particles are charged. Finally, recent data-analysis methods that have been applied to the aerosol charging states obtained from the measurements were modified for a charge asymmetric framework. The methods were then tested on data obtained from aerosol dynamics simulations. The methods were found to be able to provide reasonable estimates on the growth rate and proportion of particles formed via ion-induced nucleation, provided that the growth rate is high enough and that the charged particles do not grow much more rapidly than the neutral ones. A simple procedure for estimating whether the methods are suitable for analysing data obtained in specific conditions was provided. In this thesis, the dynamics of neutral and charged aerosol particles were studied in

  17. Radiation Reaction for a Charged Brownian Particle

    CERN Document Server

    Vlasov, A A

    2002-01-01

    As it is known a model of a charged particle with finite size is a good tool to consider the effects of self- action and backreaction, caused by electromagnetic radiation. In this work the "size" of a charged particle is induced by its stochastic Brownian vibration. Appropriate equation of particle's motion with radiation force is derived. It is shown that the solutions of this equation correctly describe the effects of radiation reaction.

  18. Charged Particle Motion in Temporal Chaotic and Spatiotemporal Chaotic Fields

    Institute of Scientific and Technical Information of China (English)

    张海云; 贺凯芬

    2002-01-01

    We investigate charged particle motion in temporal chaotic and spatiotemporal chaotic fields. In its steady wave frame a few key modes of the solution of the driven/damped nonlinear wave equation are used as the field. It is found that in the spatiotemporal chaotic field the particle drifts relative to the steady wave, in contrast to that in the temporal chaotic field where the particle motion is localized in a trough of the wave field. The result is of significance for understanding stochastic acceleration of particles.

  19. Particle Acceleration by a Solar Flare Termination Shock

    CERN Document Server

    Chen, Bin; Shen, Chengcai; Gary, Dale E; Krucker, Sam; Glesener, Lindsay

    2015-01-01

    Solar flares - the most powerful explosions in the solar system - are also efficient particle accelerators, capable of energizing a large number of charged particles to relativistic speeds. A termination shock is often invoked in the standard model of solar flares as a possible driver for particle acceleration, yet its existence and role have remained controversial. We present observations of a solar flare termination shock and trace its morphology and dynamics using high-cadence radio imaging spectroscopy. We show that a disruption of the shock coincides with an abrupt reduction of the energetic electron population. The observed properties of the shock are well-reproduced by simulations. These results strongly suggest that a termination shock is responsible, at least in part, for accelerating energetic electrons in solar flares.

  20. Electroweak interaction of particles with accelerated matter and astrophysical applications

    CERN Document Server

    Dvornikov, Maxim

    2015-01-01

    The description of physical processes in accelerated frames opens a window to numerous new phenomena. One can encounter these effects both in the subatomic world and on a macroscale. In the present work we review our recent results on the study of the electroweak interaction of particles with an accelerated background matter. In our analysis we choose the noninertial comoving frame, where matter is at rest. Our study is based on the solution of the Dirac equation, which exactly takes into account both the interaction with matter and the nonintertial effects. First, we study the interaction of ultrarelativistic neutrinos, electrons and quarks with the rotating matter. We consider the influence of the matter rotation on the resonance in neutrino oscillations and the generation of anomalous electric current of charged particles along the rotation axis. Then, we study the creation of neutrino-antineutrino pairs in a linearly accelerated matter. The applications of the obtained results for elementary particle phys...

  1. Laser ion source for particle accelerators

    CERN Document Server

    Sherwood, T R

    1995-01-01

    There is an interest in accelerating atomic nuclei to produce particle beams for medical therapy, atomic and nuclear physics, inertial confinement fusion and particle physics. Laser Ion Sources, in which ions are extracted from plasma created when a high power density laser beam pulse strikes a solid surface in a vacuum, are not in common use. However, some new developments in which heavy ions have been accelerated show that such sources have the potential to provide the beams required for high-energy accelerator systems.

  2. Stochastic Particle Acceleration in Blazar Jets

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The bulk kinetic energy of jets can be dissipated via generating tur bulent plasma waves. We examine stochastic particle acceleration in blazar jets to explain the emissions of all blazars. We show that acceleration of electrons by plasma turbulence waves with a spectrum W(k) ~ k-4/3 produces a nonthermal population of relativistic electrons whose peak frequency of synchrotron emission can fit the observational trends in the spectral energy distribution of all blazars.The plasma nonlinear processes responsible for the formation of turbulent spectrum are investigated. Increases in the interaction time of turbulent waves can produce a flatter speckrum leading to efficient particle acceleration.

  3. Quantum and classical dissipation of charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Ibarra-Sierra, V.G. [Departamento de Física, Universidad Autónoma Metropolitana at Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 México D.F. (Mexico); Anzaldo-Meneses, A.; Cardoso, J.L.; Hernández-Saldaña, H. [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana at Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico); Kunold, A., E-mail: akb@correo.azc.uam.mx [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana at Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico); Roa-Neri, J.A.E. [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana at Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico)

    2013-08-15

    A Hamiltonian approach is presented to study the two dimensional motion of damped electric charges in time dependent electromagnetic fields. The classical and the corresponding quantum mechanical problems are solved for particular cases using canonical transformations applied to Hamiltonians for a particle with variable mass. Green’s function is constructed and, from it, the motion of a Gaussian wave packet is studied in detail. -- Highlights: •Hamiltonian of a damped charged particle in time dependent electromagnetic fields. •Exact Green’s function of a charged particle in time dependent electromagnetic fields. •Time evolution of a Gaussian wave packet of a damped charged particle. •Classical and quantum dynamics of a damped electric charge.

  4. Test particle acceleration in torsional fan reconnection

    Science.gov (United States)

    Hosseinpour, M.

    2014-12-01

    Magnetic reconnection is understood to be a potential mechanism for particle acceleration in astrophysical and space plasmas, especially in solar flares. Torsional fan reconnection is one of the proposed mechanisms for steady-state three-dimensional (3D) magnetic reconnection. By using the magnetic and electric fields for `torsional fan reconnection', the features of test particle acceleration with input parameters for the solar corona are investigated numerically. We show that torsional fan reconnection is potentially an efficient particle accelerator and a proton can gain up to tens of MeV of kinetic energy within only a few milliseconds. Although the final kinetic energy of the accelerated particle depends on the injection position but there exists only one scenario for the particle's trajectory with different initial positions in which the particle is accelerated on the fan plane. Moreover, adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory. These results are compared with those of torsional spine reconnection.

  5. ABCD-Type Law for Charged-Particle Beam Transport in Paraxial Approximation

    Institute of Scientific and Technical Information of China (English)

    陈宝信; 孙别和

    2003-01-01

    Based on the similarity between charged-particle beam transversal transport and transmission of ellipse Gaussian light beam in paraxial approximation, it is shown that charged-particle beam transversal transport in real space is governed by the ABCD-type law for a complex curvature radius of the charged-particle beam in which the beam transverse emittance plays the role of wavelength; from this, a novel technique for characterizing charged-particle beam is proposed. Finally, this analogy provides an insight observation that it is hopeful to attain possible coherent charged-particle beam in favourable accelerator environment.

  6. Acceleration of superparamagnetic particles with magnetic fields

    Science.gov (United States)

    Stange, R.; Lenk, F.; Bley, T.; Boschke, E.

    2017-04-01

    High magnetic capture efficiency in the context of Biomagnetic Separation (BMS) using superparamagnetic particles (SMPs) requires efficient mixing and high relative velocities between cellular and other targets and SMPs. For this purpose, batch processes or microfluidic systems are commonly used. Here, we analyze the characteristics of an in-house developed batch process experimental setup, the Electromagnetic Sample Mixer (ESM) described earlier. This device uses three electromagnets to increase the relative velocity between SMPs and targets. We carry out simulations of the magnetic field in the ESM and in a simpler paradigmatic setup, and thus were able to calculate the force field acting on the SMPs and to simulate their relative velocities and fluid dynamics due to SMP movement. In this way we were able to show that alternate charging of the magnets induces a double circular stream of SMPs in the ESM, resulting in high relative velocities of SMPs to the targets. Consequently, due to the conservation of momentum, the fluid experiences an acceleration induced by the SMPs. We validated our simulations by microscopic observation of the SMPs in the magnetic field, using a homemade apparatus designed to accommodate a long working-distance lens. By comparing the results of modeling this paradigmatic setup with the experimental observations, we determined that the velocities of the SMPs corresponded to the results of our simulations.

  7. Trapped charged particles a graduate textbook with problems and solutions

    CERN Document Server

    Madsen, Niels; Thompson, Richard C

    2016-01-01

    At Les Houches in January 2015, experts in the field of particle trapping came together to discuss the fundamental physics of traps and the different types of applications. This textbook collates the lectures delivered there; the Second Winter School on Physics with Trapped Charged Particles. Taken as a whole, the book gives an overview of why traps for charged particles are important, how they work, their special features and limitations, and their application in areas such as precision measurements, mass spectrometry, optical clocks, plasma physics, antihydrogen creation, quantum simulation and quantum information processing. Chapters from various world experts include those on the basic properties of Penning traps, RF traps and particle accelerators, as well as those covering important practical aspects such as vacuum systems, detection techniques, and different types of particle cooling including laser cooling. Finally, individual chapters deal with the different areas of application listed above. Each ...

  8. Space charges can significantly affect the dynamics of accelerator maps

    Science.gov (United States)

    Bountis, Tassos; Skokos, Charalampos

    2006-10-01

    Space charge effects can be very important for the dynamics of intense particle beams, as they repeatedly pass through nonlinear focusing elements, aiming to maximize the beam's luminosity properties in the storage rings of a high energy accelerator. In the case of hadron beams, whose charge distribution can be considered as “frozen” within a cylindrical core of small radius compared to the beam's dynamical aperture, analytical formulas have been recently derived [C. Benedetti, G. Turchetti, Phys. Lett. A 340 (2005) 461] for the contribution of space charges within first order Hamiltonian perturbation theory. These formulas involve distribution functions which, in general, do not lead to expressions that can be evaluated in closed form. In this Letter, we apply this theory to an example of a charge distribution, whose effect on the dynamics can be derived explicitly and in closed form, both in the case of 2-dimensional as well as 4-dimensional mapping models of hadron beams. We find that, even for very small values of the “perveance” (strength of the space charge effect) the long term stability of the dynamics changes considerably. In the flat beam case, the outer invariant “tori” surrounding the origin disappear, decreasing the size of the beam's dynamical aperture, while beyond a certain threshold the beam is almost entirely lost. Analogous results in mapping models of beams with 2-dimensional cross section demonstrate that in that case also, even for weak tune depressions, orbital diffusion is enhanced and many particles whose motion was bounded now escape to infinity, indicating that space charges can impose significant limitations on the beam's luminosity.

  9. Space charges can significantly affect the dynamics of accelerator maps

    Energy Technology Data Exchange (ETDEWEB)

    Bountis, Tassos [Department of Mathematics, University of Patras, GR-26500 Patras (Greece) and Center for Research and Applications of Nonlinear Systems (CRANS), University of Patras, GR-26500 Patras (Greece)]. E-mail: tassos50@otenet.gr; Skokos, Charalampos [Center for Research and Applications of Nonlinear Systems (CRANS), University of Patras, GR-26500 Patras (Greece)

    2006-10-09

    Space charge effects can be very important for the dynamics of intense particle beams, as they repeatedly pass through nonlinear focusing elements, aiming to maximize the beam's luminosity properties in the storage rings of a high energy accelerator. In the case of hadron beams, whose charge distribution can be considered as 'frozen' within a cylindrical core of small radius compared to the beam's dynamical aperture, analytical formulas have been recently derived [C. Benedetti, G. Turchetti, Phys. Lett. A 340 (2005) 461] for the contribution of space charges within first order Hamiltonian perturbation theory. These formulas involve distribution functions which, in general, do not lead to expressions that can be evaluated in closed form. In this Letter, we apply this theory to an example of a charge distribution, whose effect on the dynamics can be derived explicitly and in closed form, both in the case of 2-dimensional as well as 4-dimensional mapping models of hadron beams. We find that, even for very small values of the 'perveance' (strength of the space charge effect) the long term stability of the dynamics changes considerably. In the flat beam case, the outer invariant 'tori' surrounding the origin disappear, decreasing the size of the beam's dynamical aperture, while beyond a certain threshold the beam is almost entirely lost. Analogous results in mapping models of beams with 2-dimensional cross section demonstrate that in that case also, even for weak tune depressions, orbital diffusion is enhanced and many particles whose motion was bounded now escape to infinity, indicating that space charges can impose significant limitations on the beam's luminosity.

  10. Formation of spectrum of accelerated particles and the hydromagnetic turbulence in the variable magnetic field

    CERN Document Server

    Savane, Y S; Faza-Barry, M; Lomonossov, V

    2002-01-01

    We study the acceleration of charged particles by the variable magnetic field. The study is based on the determination of spectrum of accelerated particles and the spectrum of hydro magnetic turbulence. We plan the self-consistent system of equation and we also find out the solution of the system for the spectrum of particles and hydro magnetic turbulence with the conditions of effective acceleration in the cosmic space of solar system.

  11. Electromagnetic fields and potentials generated by massless charged particles

    CERN Document Server

    Azzurli, Francesco

    2014-01-01

    We provide for the first time the exact solution of Maxwell's equations for a massless charged particle moving on a generic trajectory at the speed of light. In particular we furnish explicit expressions for the vector potential and the electromagnetic field, which were both previously unknown, finding that they entail different physical features for bounded and unbounded trajectories. With respect to the standard Lienard-Wiechert field the electromagnetic field acquires singular delta-like contributions whose support and dimensionality depend crucially on whether the motion is a) linear, b) accelerated unbounded, c) accelerated bounded. In the first two cases the particle generates a planar shock-wave-like electromagnetic field traveling along a straight line. In the second and third cases the field acquires, in addition, a delta-like contribution supported on a physical singularity-string attached to the particle. For generic accelerated motions a genuine radiation field is also present, represented by a re...

  12. Non-accelerator particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, R.I.

    1990-01-01

    The goals of this research are the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We are currently engaged in construction of the MACRO detector, an Italian-American collaborative research instrument with a total particle acceptance of 10,000 m{sup 2}sr, which will perform a sensitive search for magnetic monopoles using excitation-ionization methods. Other major objective of the MACRO experiment are to search for astrophysical high energy neutrinos expected to be emitted by such objects as Vela X-1, LMC X-4 and SN-1987A and to search for low energy neutrino bursts from gravitational stellar collapse. We are also working on BOREX, a liquid scintillation solar neutrino experiment and GRANDE, a proposed very large area surface detector for astrophysical neutrinos, and on the development of new techniques for liquid scintillation detection.

  13. Charged particles constrained to a curved surface

    CERN Document Server

    Müller, Thomas

    2012-01-01

    We study the motion of charged particles constrained to arbitrary two-dimensional curved surfaces but interacting in three-dimensional space via the Coulomb potential. To speed-up the interaction calculations, we use the parallel compute capability of the Compute Unified Device Architecture (CUDA) of todays graphics boards. The particles and the curved surfaces are shown using the Open Graphics Library (OpenGL). The paper is intended to give graduate students, who have basic experiences with electrostatics and differential geometry, a deeper understanding in charged particle interactions and a short introduction how to handle a many particle system using parallel computing on a single home computer

  14. Further Problems with Integral Spin Charged Particles

    Directory of Open Access Journals (Sweden)

    Comay E.

    2013-07-01

    Full Text Available The structure of the Lagrangian density of quantum theories of electrically charged particles is analyzed. It is pointed out that a well known and self-consistent expression exists for the electromagnetic interactions of a spin-1/2 Dirac particle. On the other hand, using the Noether theorem, it is shown that no such expression exists for the spin-0 Klein-Gordon charged particle as well as for the W spin-1 particle. It is also explained why effective expressions used in practical analysis of collider data cannot be a part of a self-consistent theory. The results cast doubt on the validity of the electroweak theory.

  15. Charged particle therapy: the physics of interaction.

    Science.gov (United States)

    Lomax, Antony J

    2009-01-01

    Particle therapy has a long and distinguished history with more than 50,000 patients having been treated, mainly with high-energy proton therapy. Particularly, for proton therapy, there is an increasing interest in exploiting the physical characteristics of charged particles for further improving the potential of radiation therapy. In this article, we review the most important interactions of charged particles with matter and describe the basic physical principles that underlie why particle beams behave the way they do and why such a behavior could bring many benefits in radiation therapy.

  16. Observation of particle acceleration in laboratory magnetosphere

    CERN Document Server

    Kawazura, Yohei; Nishiura, Masaki; Saitoh, Haruhiko; Yano, Yoshihisa; Nogami, Tomoaki; Sato, Naoki; Yamasaki, Miyuri; Kashyap, Ankur; Mushiake, Toshiki

    2015-01-01

    The self-organization of magnetospheric plasma is brought about by inward diffusion of magnetized particles. Not only creating a density gradient toward the center of a dipole magnetic field, the inward diffusion also accelerates particles and provides a planetary radiation belt with high energy particles. Here, we report the first experimental observation of a 'laboratory radiation belt' created in the Ring Trap 1 (RT-1) device. By spectroscopic measurement, we found an appreciable anisotropy in the ion temperature, proving the betatron acceleration mechanism which heats particles in the perpendicular direction with respect to the magnetic field when particles move inward. The energy balance model including the heating mechanism explains the observed ion temperature profile.

  17. Observation of particle acceleration in laboratory magnetosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kawazura, Y.; Yoshida, Z.; Nishiura, M.; Saitoh, H.; Yano, Y.; Nogami, T.; Sato, N.; Yamasaki, M.; Kashyap, A.; Mushiake, T. [Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561 (Japan)

    2015-11-15

    The self-organization of magnetospheric plasma is brought about by inward diffusion of magnetized particles. Not only creating a density gradient toward the center of a dipole magnetic field, the inward diffusion also accelerates particles and provides a planetary radiation belt with high energy particles. Here, we report the first experimental observation of a “laboratory radiation belt” created in the ring trap 1 device. By spectroscopic measurement, we found an appreciable anisotropy in the ion temperature, proving the betatron acceleration mechanism which heats particles in the perpendicular direction with respect to the magnetic field when particles move inward. The energy balance model, including the heating mechanism, explains the observed ion temperature profile.

  18. Diagnostic for charging and damage of dielectrics in accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT (United States)

    2014-12-01

    Particle accelerators for discovery science, industrial and medical applications employ dielectric elements that can be altered or seriously damaged by the accelerated particles. This project is to develop a diagnostic test to anticipate when these effects can be avoided, thereby increasing the reliability and lowering the cost of the accelerators.

  19. Kinetic Simulations of Particle Acceleration at Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Caprioli, Damiano [Princeton University; Guo, Fan [Los Alamos National Laboratory

    2015-07-16

    Collisionless shocks are mediated by collective electromagnetic interactions and are sources of non-thermal particles and emission. The full particle-in-cell approach and a hybrid approach are sketched, simulations of collisionless shocks are shown using a multicolor presentation. Results for SN 1006, a case involving ion acceleration and B field amplification where the shock is parallel, are shown. Electron acceleration takes place in planetary bow shocks and galaxy clusters. It is concluded that acceleration at shocks can be efficient: >15%; CRs amplify B field via streaming instability; ion DSA is efficient at parallel, strong shocks; ions are injected via reflection and shock drift acceleration; and electron DSA is efficient at oblique shocks.

  20. Machine Protection: Availability for Particle Accelerators

    CERN Document Server

    Apollonio, Andrea; Schmidt, Ruediger

    2015-03-16

    Machine availability is a key indicator for the performance of the next generation of particle accelerators. Availability requirements need to be carefully considered during the design phase to achieve challenging objectives in different fields, as e.g. particle physics and material science. For existing and future High-Power facilities, such as ESS (European Spallation Source) and HL-LHC (High-Luminosity LHC), operation with unprecedented beam power requires highly dependable Machine Protection Systems (MPS) to avoid any damage-induced downtime. Due to the high complexity of accelerator systems, finding the optimal balance between equipment safety and accelerator availability is challenging. The MPS architecture, as well as the choice of electronic components, have a large influence on the achievable level of availability. In this thesis novel methods to address the availability of accelerators and their protection systems are presented. Examples of studies related to dependable MPS architectures are given i...

  1. New Charged Particles from Higgs Couplings

    CERN Document Server

    Cohen, Andrew G

    2012-01-01

    The recently reported observation of a new particle with mass about 125 GeV and couplings generally resembling those of the Standard Model Higgs boson provides a potential probe of the physics of electroweak symmetry breaking. Although the current data only provides hints, we suggest a particular combination of Higgs couplings as an assay for new charged particles connected with electroweak symmetry breaking, and construct a simple model with charge 5/3 quarks as a demonstration of its use.

  2. Infinite Blueshift of Charged Null Particles

    OpenAIRE

    Mann, R. B.; Sajko, W. N.

    1994-01-01

    We demonstrate that charged null particles can be infinitely blue\\-shifted in a Kerr-Newman spacetime. The surface of infinite blueshift can be outside of the ergosphere in a Kerr-Newman spacetime, and outside of the outer event horizon for a Reissner-Nordstrom spacetime. Implications for extensions of the standard model which incorporate charged neutrinos are discussed.

  3. Anomalous/Fractional Diffusion in Particle Acceleration Processes.

    Science.gov (United States)

    Bian, Nicolas

    2016-07-01

    This talk is aimed at reviewing a certain number of theoretical aspects concerning the relation between stochastic acceleration and anomalous/fractional transport of particles. As a matter of fact, anomalous velocity-space diffusion is required within any stochastic acceleration scenario to explain the formation of the ubiquitous power-law tail of non-thermal particles, as observed e.g. in the accelerated distribution of electrons during solar flares. I will establish a classification scheme for stochastic acceleration models involving turbulence in magnetized plasmas. This classification takes into account both the properties of the accelerating electromagnetic field, and the nature of the spatial transport (possibly fractional) of charged particles in the acceleration region. I will also discuss recent attempts to obtain spatially non-local and fractional diffusion equations directly from first principles, starting either from the Fokker-Planck equation in the large mean free-path regime or the Boltzmann equation involving velocity-space relaxation toward the kappa distribution instead of the standard Maxwellian distribution.

  4. Hawking radiation of scalar particles from accelerating and rotating black holes

    Energy Technology Data Exchange (ETDEWEB)

    Gillani, Usman A.; Rehman, Mudassar; Saifullah, K., E-mail: mani_precious2001@yahoo.com, E-mail: mudassar051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)

    2011-06-01

    Hawking radiation of uncharged and charged scalar particles from accelerating and rotating black holes is studied. We calculate the tunneling probabilities of these particles from the rotation and acceleration horizons of these black holes. Using this method we recover the correct Hawking temperature as well.

  5. Kerr Naked Singularities as Particle Accelerators

    CERN Document Server

    Patil, Mandar

    2011-01-01

    We investigate here the particle acceleration by Kerr naked singularities. We consider a collision between particles dropped in from infinity at rest, which follow geodesic motion in the equatorial plane, with angular momentum of one of the particles in an appropriate finite range of values. The absence of an event horizon and the repulsive nature of angular momentum makes it possible for the initially infalling particle to turn back as an outgoing particle and then collide with another infalling particle. When these particles collide at a location close to what would have been the event horizon in the extremal Kerr blackhole case, the center of mass energy of collision turns out to be arbitrarily large depending on how close is the Kerr naked singularity to extremality. We briefly discuss the possible astrophysical consequences of this process and suggest that the fast rotating Kerr configurations could provide a good cosmic laboratory to probe ultra-high-energy physics.

  6. A particle accelerator probes artifacts

    CERN Document Server

    Dran, J C; Salomon, J

    2002-01-01

    The AGLAE system is made up of a 2 mega volts electrostatic accelerator and of 3 irradiation lines: one leads to a vacuum enclosure in which targets are irradiated and the 2 others lines are designed to irradiate targets under an air or helium atmosphere. The AGLAE system is located in the premises of the Louvre museum in Paris and is devoted to the study of cultural objects through ion beam analysis (IBA). 4 techniques are used: -) proton-induced X-ray emission (PIXE) -) proton-induced gamma ray (PIGE) -) Rutherford backscattering spectrometry (NRS) and -) nuclear reaction analysis (NRA). A decisive progress has permitted the direct analysis of artifacts without sampling. The object itself is set just a few millimeters away from the exit window of the beam in an air or helium atmosphere. The exit window must be resistant enough to bear the atmospheric pressure and the damages caused by the proton beam but must be thin enough to not deteriorate the quality of the beam. By using a 10 sup - sup 7 m thick exit w...

  7. Hybrid Simulations of Particle Acceleration at Shocks

    CERN Document Server

    Caprioli, Damiano

    2014-01-01

    We present the results of large hybrid (kinetic ions - fluid electrons) simulations of particle acceleration at non-relativistic collisionless shocks. Ion acceleration efficiency and magnetic field amplification are investigated in detail as a function of shock inclination and strength, and compared with predictions of diffusive shock acceleration theory, for shocks with Mach number up to 100. Moreover, we discuss the relative importance of resonant and Bell's instability in the shock precursor, and show that diffusion in the self-generated turbulence can be effectively parametrized as Bohm diffusion in the amplified magnetic field.

  8. Non-accelerator particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, R.I.; Lane, C.E.

    1991-09-01

    The goals of this research are the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We are working on the MACRO experiment, which employs a large area underground detector to search for grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low and high energy neutrinos: the {nu}IMB project, which seeks to refurbish and upgrade the IMB water Cerenkov detector to perform an improved proton decay search together with a long baseline reactor neutrino oscillation experiment using a kiloton liquid scintillator (the Perry experiment); and development of technology for improved liquid scintillators and for very low background materials in support of the MACRO and Perry experiments and for new solar neutrino experiments. 21 refs., 19 figs., 6 tabs.

  9. Non-accelerator particle physics

    Science.gov (United States)

    Steinberg, R. I.; Lane, C. E.

    1991-09-01

    The goals of this research are the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We are working on the MACRO experiment, which employs a large area underground detector, to search for grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low and high energy neutrinos. The NuIMB project seeks to: refurbish and upgrade the IMB water Cerenkov detector to perform an improved proton decay search together with a long baseline reactor neutrino oscillation experiment using a kiloton liquid scintillator (the Perry experiment); and to develop technology for improved liquid scintillators, very low background materials in support of the MACRO and Perry experiments, and for new solar neutrino experiments.

  10. Non-accelerator particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, R.I.; Lane, C.E.

    1991-08-01

    The goals of this research were the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We have worked on the MACRO experiment, which is employing a large area underground detector to search for grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low and high energy neutrinos; the {nu}IMB project, which seeks to refurbish and upgrade the IMB water Cerenkov detector to perform an improved proton decay search together with a long baseline reactor neutrino oscillation experiments using a one kiloton liquid scintillator (the Perry experiment); and development of technology for improved liquid scintillators and for very low background materials in support of the MACRO and Perry experiments and for new solar neutrino experiments.

  11. Transverse Space-Charge Effects in Circular Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Sacherer, Frank James

    1968-10-30

    The particles in an accelerator interact with one another by electromagnetic forces and are held together by external focusing forces. Such a many-body system has a large number of transverse modes of oscillation (plasma oscillations) that can be excited at characteristic frequencies by errors in the external guide field. In Part I we examine one mode of oscillation in detail, namely the quadrupole mode that is excited in uniformly charged beams by gradient errors. We derive self-consistent equations of motion for the beam envelope and solve these equations for the case in which the space-charge force is much less than the external focusing force, i.e., for strong-focusing synchrotrons. We find that the resonance intensity is shifted from the value predicted by the usual transverse incoherent space-charge limit; moreover, because the space-charge force depends on the shape and size of the beam, the beam growth in always limited. For gradient errors of the magnitude normally present in strong-focusing synchrotrons, the increase in beam size is small provided the beam parameters are properly chosen; otherwise the growth may be large. Thus gradient errors need not impose a limit on the number of particles that can be accelerated. In Part II we examine the other modes of collective oscillation that are excited by machine imperfections. For simplicity we consider only one-dimensional beams that are confined by harmonic potentials, and only small-amplitude oscillations. The linearized Vlasov and Poisson equations are used to find the twofold infinity of normal modes and eigenfrequencies for the stationary distribution that has uniform charge density in real space. In practice, only the low-order modes (the dipole, quadrupole, sextupole, and one or two additional modes) will be serious, and the resonant conditions for these modes are located on a tune diagram. These results, which are valid for all beam intensities, are compared with the known eigenfrequencies for the

  12. Charged Particle Monitor on the AstroSat mission

    CERN Document Server

    Rao, A R; Bhargava, Yash; Khanna, Rakesh; Hingar, M K; Kutty, A P K; Malkar, J P; Basak, Rupal; Sreekumar, S; Samuel, Essy; Priya, P; Vinod, P; Bhattacharya, D; Bhalerao, V; Vadawale, S V; Mithun, N P S; Pandiyan, R; Subbarao, K; Seetha, S; Sarma, K Suryanarayana

    2016-01-01

    Charged Particle Monitor (CPM) on-board the AstroSat satellite is an instrument designed to detect the flux of charged particles at the satellite location. A Cesium Iodide Thallium (CsI(Tl)) crystal is used with a Kapton window to detect protons with energies greater than 1 MeV. The ground calibration of CPM was done using gamma-rays from radioactive sources and protons from particle accelerators. Based on the ground calibration results, energy deposition above 1 MeV are accepted and particle counts are recorded. It is found that CPM counts are steady and the signal for the onset and exit of South Atlantic Anomaly (SAA) region are generated in a very reliable and stable manner.

  13. Black hole horizons and quantum charged particles

    CERN Document Server

    Jaramillo, José Luis

    2014-01-01

    We point out a structural similarity between the characterization of black hole apparent horizons as stable marginally outer trapped surfaces (MOTS) and the quantum description of a non-relativistic charged particle moving in given magnetic and electric fields on a closed surface. Specifically, the spectral problem of the MOTS-stability operator corresponds to a stationary quantum particle with a formal fine-structure constant $\\alpha$ of negative sign. We discuss how such analogy enriches both problems, illustrating this with the insights into the MOTS-spectral problem gained from the analysis of the spectrum of the quantum charged particle Hamiltonian.

  14. First Electrooptical Detection of Charged Particles

    CERN Document Server

    Lazarus, D M; Kowalski, L A; Kraus, D E; Larsen, R; Magurno, B; Nikas, D; Ozben, C; Semertzidis, Y K; Srinivasan-Rao, T; Tsang, Thomas

    2000-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a birefringent crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured in a single shot, 120 ps, was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds promise for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

  15. Electro-optical detection of charged particles

    CERN Document Server

    Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R; Lazarus, D M; Magurno, B; Nikas, D; Ozben, C; Srinivasan-Rao, T; Tsang, Thomas

    2000-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO sub 3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

  16. Laser and Particle Guiding Micro-Elements for Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Plettner, T.; Gaume, R.; Wisdom, J.; /Stanford U., Phys. Dept.; Spencer, J.; /SLAC

    2005-06-07

    Laser driven particle accelerators require sub-micron control of the laser field as well as precise electron-beam guiding so fabrication techniques that allow integrating both elements into an accelerator-on-chip format become critical for the success of such next generation machines. Micromachining technology for silicon has been shown to be one such feasible technology in PAC2003[1] but with a variety of complications on the laser side. However, fabrication of transparent ceramics has become an interesting technology that could be applied for laser-particle accelerators in several ways. We discuss the advantages such as the range of materials available and ways to implement them followed by some different test examples we been considered. One important goal is an integrated system that avoids having to inject either laser or particle pulses into these structures.

  17. EIDOSCOPE: particle acceleration at plasma boundaries

    Science.gov (United States)

    Vaivads, A.; Andersson, G.; Bale, S. D.; Cully, C. M.; De Keyser, J.; Fujimoto, M.; Grahn, S.; Haaland, S.; Ji, H.; Khotyaintsev, Yu. V.; Lazarian, A.; Lavraud, B.; Mann, I. R.; Nakamura, R.; Nakamura, T. K. M.; Narita, Y.; Retinò, A.; Sahraoui, F.; Schekochihin, A.; Schwartz, S. J.; Shinohara, I.; Sorriso-Valvo, L.

    2012-04-01

    We describe the mission concept of how ESA can make a major contribution to the Japanese Canadian multi-spacecraft mission SCOPE by adding one cost-effective spacecraft EIDO (Electron and Ion Dynamics Observatory), which has a comprehensive and optimized plasma payload to address the physics of particle acceleration. The combined mission EIDOSCOPE will distinguish amongst and quantify the governing processes of particle acceleration at several important plasma boundaries and their associated boundary layers: collisionless shocks, plasma jet fronts, thin current sheets and turbulent boundary layers. Particle acceleration and associated cross-scale coupling is one of the key outstanding topics to be addressed in the Plasma Universe. The very important science questions that only the combined EIDOSCOPE mission will be able to tackle are: 1) Quantitatively, what are the processes and efficiencies with which both electrons and ions are selectively injected and subsequently accelerated by collisionless shocks? 2) How does small-scale electron and ion acceleration at jet fronts due to kinetic processes couple simultaneously to large scale acceleration due to fluid (MHD) mechanisms? 3) How does multi-scale coupling govern acceleration mechanisms at electron, ion and fluid scales in thin current sheets? 4) How do particle acceleration processes inside turbulent boundary layers depend on turbulence properties at ion/electron scales? EIDO particle instruments are capable of resolving full 3D particle distribution functions in both thermal and suprathermal regimes and at high enough temporal resolution to resolve the relevant scales even in very dynamic plasma processes. The EIDO spin axis is designed to be sun-pointing, allowing EIDO to carry out the most sensitive electric field measurements ever accomplished in the outer magnetosphere. Combined with a nearby SCOPE Far Daughter satellite, EIDO will form a second pair (in addition to SCOPE Mother-Near Daughter) of closely

  18. Search milli-charged particles at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Langeveld, W.G.J. [Stanford Univ., CA (United States)

    1997-01-01

    Particles with electric charge q {triple_bond} Qe {le} 10{sup -3} e and masses in the range 1-1000 MeV/c{sup 2} are not excluded by present experiments or by astrophysical or cosmological arguments. A beam dump experiment uniquely suited to the detection of such {open_quotes}milli-charged{close_quotes} particles has been carried out at SLAC, utilizing the short-duration pulses of the SLC electron beam to establish a tight coincidence window for the signal. The detector, a large scintillation counter sensitive to very small energy depositions, provided much greater sensitivity than previous searches. Analysis of the data leads to the exclusion of a substantial portion of the charge-mass plane. In this report, a preliminary mass-dependent upper limit is presented for the charge of milli-charged particles, ranging from Q = 1.7 x 10{sup -5} at milli-charged particle mass 0.1 MeV/c{sup 2} to Q = 9.5 x 10{sup -4} at 100 MeV/c{sup 2}.

  19. AXEL-2016: Introduction to Particle Accelerators

    CERN Multimedia

    2016-01-01

    AXEL-2016 is the latest in a yearly lecture series on particle accelerators given at CERN within the framework of the 2016 Technical Training Programme. As part of the BE department's Operation group’s shutdown lecture series, this general accelerator physics module has been offered since 2003 as a joint venture between the BE department and the Technical Training team and is open to the wider CERN community.    The lecturer is Rende Steerenberg, deputy leader of the Operation group and PS section leader. Programme: basic mathematics; transverse optics; lattice calculations; resonances; longitudinal motion; transfer lines, injection and ejection; longitudinal and transverse beam instabilities; colliders. A detailed programme is available on the AXEL-2016 webpage. Target audience: designed for technicians who are operating an accelerator or whose work is closely linked to accelerators, but also open to technicians, engineers and physicists interested i...

  20. Current-voltage relationship in the auroral particle acceleration region

    Directory of Open Access Journals (Sweden)

    M. Morooka

    2004-11-01

    Full Text Available The current-voltage relationship in the auroral particle acceleration region has been studied statistically by the Akebono (EXOS-D satellite in terms of the charge carriers of the upward field-aligned current. The Akebono satellite often observed field-aligned currents which were significantly larger than the model value predicted by Knight (1973. We compared the upward field-aligned current estimated by three different methods, and found that low-energy electrons often play an important role as additional current carriers, together with the high-energy primary electrons which are expected from Knight's relation. Such additional currents have been observed especially at high and middle altitudes of the particle acceleration region. Some particular features of electron distribution functions, such as "cylindrical distribution functions" and "electron conics", have often been observed coinciding with the additional currents. They indicated time variability of the particle acceleration region. Therefore, we have concluded that the low-energy electrons within the "forbidden" region of electron phase space in the stationary model often contribute to charge carriers of the current because of the rapid time variability of the particle acceleration region. "Cylindrical distribution functions" are expected to be found below the time-varying potential difference. We statistically examined the locations of "cylindrical distribution function", and found that their altitudes are related to the location where the additional currents have been observed. This result is consistent with the idea that the low-energy electrons can also carry significant current when the acceleration region changes in time.

  1. PARTICLE DISTRIBUTION IN CENTRIFUGAL ACCELERATING FIELDS

    Institute of Scientific and Technical Information of China (English)

    Yu Sirong; Zhang Xinping; He Zhenming; Liu Yaohui

    2003-01-01

    Based on continuum theory and moving law of particles, a model is presented to obtain gradient distribution of particles in centrifugal accelerating field, by which the particle distribution in gradient composite material can be predicted. The simulation shows with increases in rotating time, four regions gradually appear from the internal periphery to the external one, they are free region, transition region, steady region and surface reinforced region,and the latest three regions are defined as a rich region. Finally, the steady region disappears, and the rich region only includes transition region and surface reinforced region. The influences of centrifugal acceleration coefficient G,primary volume fraction (0,pouring temperature (p and density difference between the particle and the metal matrix on particles gradient distribution are studied in detail. The results of the theoretical analysis agree with experiment ones. Both of analysis and experiment results indicate that with the increase in G and (p, the particle distribution becomes more centralized and the consistence of particle in the surface periphery becomes larger.

  2. Power Supplies for High Energy Particle Accelerators

    Science.gov (United States)

    Dey, Pranab Kumar

    2016-06-01

    The on-going research and the development projects with Large Hadron Collider at CERN, Geneva, Switzerland has generated enormous enthusiasm and interest amongst all to know about the ultimate findings on `God's Particle'. This paper has made an attempt to unfold the power supply requirements and the methodology adopted to provide the stringent demand of such high energy particle accelerators during the initial stages of the search for the ultimate particles. An attempt has also been made to highlight the present status on the requirement of power supplies in some high energy accelerators with a view that, precautionary measures can be drawn during design and development from earlier experience which will be of help for the proposed third generation synchrotron to be installed in India at a huge cost.

  3. Coulomb field of an accelerated charge physical and mathematical aspects

    CERN Document Server

    Alexander, F J; Alexander, Francis J.; Gerlach, Ulrich H.

    1991-01-01

    The Maxwell field equations relative to a uniformly accelerated frame, and the variational principle from which they are obtained, are formulated in terms of the technique of geometrical gauge invariant potentials. They refer to the transverse magnetic (TM) and the transeverse electric (TE) modes. This gauge invariant "2+2" decomposition is used to see how the Coulomb field of a charge, static in an accelerated frame, has properties that suggest features of electromagnetism which are different from those in an inertial frame. In particular, (1) an illustrative calculation shows that the Larmor radiation reaction equals the electrostatic attraction between the accelerated charge and the charge induced on the surface whose history is the event horizon, and (2) a spectral decomposition of the Coulomb potential in the accelerated frame suggests the possibility that the distortive effects of this charge on the Rindler vacuum are akin to those of a charge on a crystal lattice.

  4. Acceleration of Small Dust Grains due to Charge Fluctuations

    CERN Document Server

    Hoang, Thiem

    2011-01-01

    We consider the acceleration of very small dust grains including Polycyclic Aromatic Hydrocarbons (PAHs) arising from the electrostatic interactions of dust grains that have charge fluctuates in time due to charging events. We simulate the charge fluctuations of very small grains due to their sticking collisions with electrons and ions in plasma and the emission of photoelectrons by UV photons using Monte Carlo method. We identify the acceleration induced by the charge fluctuations as the dominant acceleration mechanism of very small grains in the diffuse interstellar medium (ISM). We show that this acceleration mechanism is more efficient for environments with low ionization, where the charge fluctuations are slow but have a large amplitude. We also discuss the implications of the present mechanism for grain coagulation and shattering in the diffuse ISM, molecular clouds and protoplanetary disks.

  5. Charged particle detection in organic semiconductors

    CERN Document Server

    Beckerle, P

    2000-01-01

    Polyacetylene is an organic semiconductor in which charges can be set free by a traversing charged particle, transported by an electric field to read-out electrodes and, subsequently, amplified and recorded in a way similar to what happens in a silicon-drift detector. In an experimental investigation of the features of this charge transport in thin foils we find drift velocities of the order of 40 cm/s. Stretching of the foils by a factor of three to four increases the drift velocity by a factor of ten and introduces a strong directionality of the charge transport. The detection efficiency of 5 MeV alpha particles in a few micron thin stretched foil is around 70%.

  6. Stochastic Particle Acceleration by Helical Turbulence in Solar Flares

    CERN Document Server

    Fleishman, Gregory D

    2012-01-01

    Flaring release of magnetic energy in solar corona is only possible if the magnetic field deviates from a potential one. We show that the linear MHD modes excited on top of the non-potential magnetic field possess a nonzero kinetic helicity. Accordingly, this necessarily results in a noticeable kinetic helicity of the turbulence, composed of these linear modes with various scales and random phases, generated at the flare site by the primary energy release, which may be important for many applications. In particular, a nonzero turbulence helicity has a potentially strong effect on the particle acceleration because the helical component of the turbulence induces a mean regular large-scale (DC) electric field capable of directly accelerating the charged particles in addition to the commonly considered stochastic turbulent electric field. In this paper, we derive the kinetic helicity density of the linear MHD modes excited on top of a twisted large-scale magnetic field, estimate the corresponding turbulence helic...

  7. Particle acceleration by ultra-intense laser-plasma interactions

    CERN Document Server

    Nakajima, K

    2002-01-01

    The mechanism of particle acceleration by ultra-increase laser-plasma interaction is explained. Laser light can generate very high electric field by focusing with electromagnetic field matched phase with frequency. 1018 W/cm sup 2 laser light produce about 3 TV/m electric field. Many laser accelerators, which particle acceleration method satisfies phase matching particle and electric field, are proposed. In these accelerators, the Inverse Cherenkov Accelerator, Inverse FEL Accelerator and Laser-Plasma Accelerator are explained. Three laser-plasma acceleration mechanisms: Plasma Beat Wave Accelerator, Laser Wake-Field Accelerator (LWFA) and Self-Modulated LWFA, showed particle acceleration by experiments. By developing a high speed Z pinch capillary-plasma optical waveguide, 2.2 TW and 90 fs laser pulse could be propagated 2 cm at 40 mu m focusing radius in 1999. Dirac acceleration or ultra-relativistic ponderomotive acceleration mechanism can increase energy exponentially. (S.Y.)

  8. Test particle acceleration in explosive magnetohydrodynamic reconnection

    CERN Document Server

    Ripperda, Bart; Xia, Chun; Keppens, Rony

    2016-01-01

    Magnetic reconnection is the mechanism behind many violent phenomena in the universe. We demonstrate that energy released during reconnection can lead to non-thermal particle distribution functions. We use a method in which we combine resistive magnetohydrodynamics (MHD) with relativistic test particle dynamics. Using our open-source grid-adaptive MPI-AMRVAC software, we simulate global MHD evolution combined with test particle treatments in MHD snapshots. This approach is used to evaluate particle acceleration in explosive reconnection. The reconnection is triggered by an ideal tilt instability in two-and-a-half dimensional (2.5D) scenarios and by a combination of ideal tilt and kink instabilities in three-dimensional (3D) scenarios. These instabilities occur in a system with two parallel, adjacent, repelling current channels in an initially force-free equilibrium, as a simplified representation of flux ropes in a stellar magnetosphere. The current channels undergo a rotation and a separation on Alfv\\'enic t...

  9. Particle Acceleration and Heating by Turbulent Reconnection

    CERN Document Server

    Vlahos, Loukas; Isliker, Heinz; Tsiolis, Vassilios; Anastasiadis, Anastasios

    2016-01-01

    Turbulent flows in the solar wind, large scale current sheets, multiple current sheets, and shock waves lead to the formation of environments in which a dense network of current sheets is established and sustains "turbulent reconnection". We constructed a 2D grid on which a number of randomly chosen grid points are acting as {\\bf scatterers} (i.e.\\ magnetic clouds or current sheets). In particular, we study how test particles respond inside this collection of scatterers. We study the energy gain of individual particles, the evolution of their energy distribution, their escape time distribution and we determine the transport coefficients from the particle dynamics. We have shown that our model describes very well the second order Fermi energization of non relativistic plasmas in open or periodic numerical boxes, when using magnetic clouds as scatterers. Replacing the "magnetic clouds" with current sheets, we have proven that the processes are much more efficient and particle heating and acceleration depends on...

  10. Motion of charged particles in pulsar magnetospheres

    Science.gov (United States)

    Zachariades, Haris Andrea

    The motion of charges in the magnetosphere of pulsars is studied from two complementary points of view: (1) for the case of aligned magnetic and rotational axes we solve a fluid version of the Lorentz-Dirac equation, in the Landau approximation, for a two-component plasma. We start from an approximately force-free initial condition and numerically integrate the equations of motion for a time equal to 1.6 percent of one stellar rotation period. We find that the system tends to a charge-separated state in which a negative charge region above the poles is separated by a vacuum gap from a positive charge region near the equator. We see the formation of force-free regions and a tendency of the vacuum gap to spread as the integrations proceed. The energies attained by the charges are only mildly relativistic and radiation reaction does not play an important role during the integrations. The negative charge above the polar region is electrostatically bound and there is a force-free region towards which negative charge tends to flow. Some positive charge is magnetically confined near the stellar equator and other positive charge crosses magnetic field lines moving outward to the region beyond the light cylinder. The outward motion of positive charge is due to the relative magnitudes of the electric and magnetic fields. (2) For the case of non-aligned axes we study the single particle dynamics for electrons moving in the region beyond the light cylinder, again using the Landau approximation to the Lorentz-Dirac equation. The effect of the inner magnetosphere is taken into account by adding a central attractive charge. We find that there exists a class of solutions corresponding to bounded orbits beyond the light cylinder. In an independent particle picture, particles started with different initial conditions within the basin of attraction of this class of orbits eventually form corotating patterns beyond the light cylinder. For a frequently occurring particle configuration

  11. Cryogenics for Particle Accelerators and Detectors

    CERN Document Server

    Lebrun, P; Vandoni, Giovanna; Wagner, U

    2002-01-01

    Cryogenics has become a key ancillary technology of particle accelerators and detectors, contributing to their sustained development over the last fifty years. Conversely, this development has produced new challenges and markets for cryogenics, resulting in a fruitful symbiotic relation which materialized in significant technology transfer and technical progress. This began with the use of liquid hydrogen and deuterium in the targets and bubble chambers of the 1950s, 1960s and 1970s. It developed more recently with increasing amounts of liquefied noble gases - mainly argon, but also krypton and even today xenon - in calorimeters. In parallel with these applications, the availability of practical type II superconductors from the early 1960s triggered the use of superconductivity in large spectrometer magnets - mostly driven by considerations of energy savings - and the corresponding development of helium cryogenics. It is however the generalized application of superconductivity in particle accelerators - RF ac...

  12. Dynamics and transport of laser-accelerated particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Stefan

    2010-04-19

    The subject of this thesis is the investigation and optimization of beam transport elements in the context of the steadily growing field of laser-driven particle acceleration. The first topic is the examination of the free vacuum expansion of an electron beam at high current density. It could be shown that particle tracking codes which are commonly used for the calculation of space charge effects will generate substantial artifacts in the regime considered here. The artifacts occurring hitherto predominantly involve insufficient prerequisites for the Lorentz transformation, the application of inadequate initial conditions and non negligible retardation artifacts. A part of this thesis is dedicated to the development of a calculation approach which uses a more adequate ansatz calculating space charge effects for laser-accelerated electron beams. It can also be used to validate further approaches for the calculation of space charge effects. The next elements considered are miniature magnetic quadrupole devices for the focusing of charged particle beams. General problems involved with their miniaturization concern distorting higher order field components. If these distorting components cannot be controlled, the field of applications is very limited. In this thesis a new method for the characterization and compensation of the distorting components was developed, which might become a standard method when assembling these permanent magnet multipole devices. The newly developed characterization method has been validated at the Mainz Microtron (MAMI) electron accelerator. Now that we can ensure optimum performance, the first application of permanent magnet quadrupole devices in conjunction with laser-accelerated ion beams is presented. The experiment was carried out at the Z-Petawatt laser system at Sandia National Laboratories. A promising application for laser-accelerated electron beams is the FEL in a university-scale size. The first discussion of all relevant aspects

  13. Interdisciplinary glossary — particle accelerators and medicine

    Science.gov (United States)

    Dmitrieva, V. V.; Dyubkov, V. S.; Nikitaev, V. G.; Ulin, S. E.

    2016-02-01

    A general concept of a new interdisciplinary glossary, which includes particle accelerator terminology used in medicine, as well as relevant medical concepts, is presented. Its structure and usage rules are described. An example, illustrating the quickly searching technique of relevant information in this Glossary, is considered. A website address, where one can get an access to the Glossary, is specified. Glossary can be refined and supplemented.

  14. Particle Acceleration At Small-Scale Flux Ropes In The Heliosphere

    Science.gov (United States)

    Zank, G. P.; Hunana, P.; Mostafavi, P.; le Roux, J. A.; Li, G.; Webb, G. M.; Khabarova, O.; Cummings, A. C.; Stone, E. C.; Decker, R. B.

    2015-12-01

    An emerging paradigm for the dissipation of magnetic turbulence in the supersonic solar wind is via localized small-scale reconnection processes, essentially between quasi-2D interacting magnetic islands or flux roped. Charged particles trapped in merging magnetic islands can be accelerated by the electric field generated by magnetic island merging and the contraction of magnetic islands. We discuss the basic physics of particle acceleration by single magnetic islands and describe how to incorporate these ideas in a distributed "sea of magnetic islands". We describe briefly some observations, selected simulations, and then introduce a transport approach for describing particle acceleration at small-scale flux ropes. We discuss particle acceleration in the supersonic solar wind and extend these ideas to particle acceleration at shock waves. These models are appropriate to the acceleration of both electrons and ions. We describe model predictions and supporting observations.

  15. Electromagnetic fields and potentials generated by massless charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Azzurli, Francesco, E-mail: francesco.azzurli@gmail.com [Scuola Galileiana di Studi Superiori, Università degli Studi di Padova (Italy); Lechner, Kurt, E-mail: lechner@pd.infn.it [Dipartimento di Fisica e Astronomia, Università degli Studi di Padova (Italy); INFN, Sezione di Padova, Via F. Marzolo, 8, 35131 Padova (Italy)

    2014-10-15

    We provide for the first time the exact solution of Maxwell’s equations for a massless charged particle moving on a generic trajectory at the speed of light. In particular we furnish explicit expressions for the vector potential and the electromagnetic field, which were both previously unknown, finding that they entail different physical features for bounded and unbounded trajectories. With respect to the standard Liénard–Wiechert field the electromagnetic field acquires singular δ-like contributions whose support and dimensionality depend crucially on whether the motion is (a) linear, (b) accelerated unbounded, (c) accelerated bounded. In the first two cases the particle generates a planar shock-wave-like electromagnetic field traveling along a straight line. In the second and third cases the field acquires, in addition, a δ-like contribution supported on a physical singularity-string attached to the particle. For generic accelerated motions a genuine radiation field is also present, represented by a regular principal-part type distribution diverging on the same singularity-string. - Highlights: • First exact solution of Maxwell’s equations for massless charges in arbitrary motion. • Explicit expressions of electromagnetic fields and potentials. • Derivations are rigorous and based on distribution theory. • The form of the field depends heavily on whether the motion is bounded or unbounded. • The electromagnetic field contains unexpected Dirac-delta-function contributions.

  16. AXEL–2014: Introduction to Particle Accelerators

    CERN Multimedia

    2014-01-01

    AXEL-2014 is a series of courses on particle accelerators, given at CERN within the framework of the 2014 Technical Training Program. As part of the BE Department’s Operation Group Shutdown Lecture series, the general accelerator physics module has been organised since 2003 as a joint venture between the BE Department and Technical Training, and is open to the wider CERN community.   The AXEL-2014 course series is designed for technicians who are operating an accelerator or whose work is closely linked to accelerators, but it is also open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge of accelerators. However, some basic knowledge of trigonometry, matrices and differential equations, and some basic knowledge of magnetism would be an advantage. The series will be composed of 10 modules (Monday 24 March 2014 – Fri 28 March 2014, from 9 a.m. to 10:15 a.m. and from 10:45 a.m. to 12 noon), and will be given in En...

  17. Argonne lectures on particles accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Devred, A

    1999-09-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron, the particle energy is directly proportional to the product of the machine's radius times the bending magnets' field strength. Present proton experiments at the TeV scale require facilities with circumferences ranging from a few to tens of kilometers and relying on a large number (several hundred to several thousand) high field dipole magnets and high field gradient quadrupole magnets. These electro-magnets use high-current-density, low-critical-temperature superconducting cables and are cooled down at liquid helium temperature. They are among the most costly and the most challenging components of the machine. After explaining what are the various types of accelerator magnets and why they are needed (lecture 1), we briefly recall the origins of superconductivity and we review the parameters of existing superconducting particle accelerators (lecture 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb{sub 3}Sn) and we explain in details the manufacturing of NbTi wires and cables (lecture 3). We also present the difficulties of processing and insulating Nb{sub 3}Sn conductors, which so far have limited the use of this material in spite of its superior performances. We continue by discussing the two dimensional current distributions which are the most appropriate for generating pure dipole and quadrupole fields and we explain how these ideal distributions can be approximated by so called cos{theta} and cos 2{theta} coil designs (lecture 4). We also present a few alternative designs which are being investigated and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that are used in existing accelerator magnets (lecture 5) and we describe how the magnets are assembled (lecture 6). Some of the toughest

  18. Particle Accelerator Applications: Ion and Electron Irradiation in Materials Science, Biology and Medicine

    Science.gov (United States)

    Rodríguez-Fernández, Luis

    2010-09-01

    Although the developments of particle accelerators are devoted to basic study of matter constituents, since the beginning these machines have been applied with different purposes in many areas also. Today particle accelerators are essential instruments for science and technology. This work presents an overview of the main application for direct particle irradiation with accelerator in material science, biology and medicine. They are used for material synthesis by ion implantation and charged particle irradiation; to make coatings and micromachining; to characterize broad kind of samples by ion beam analysis techniques; as mass spectrometers for atomic isotopes determination. In biomedicine the accelerators are applied for the study of effects by charged particles on cells. In medicine the radiotherapy by electron irradiation is widely used, while hadrontherapy is still under development. Also, they are necessary for short life radioisotopes production required in radiodiagnostic.

  19. Particle acceleration in the vacuum gaps in black hole magnetospheres

    CERN Document Server

    Ptitsyna, K

    2015-01-01

    We consider particle acceleration in vacuum gaps in magnetospheres of black holes powered through Blandford-Znajek mechanism and embedded into radiatively-inefficient accretion flow (RIAF) environment. In such situation the gap height is limited by the onset of gamma-gamma pair production on the infrared photons originating from the RIAF. We numerically calculate acceleration and propagation of charged particles taking into account the detailed structure of electric and magnetic field in the gap and in the entire black hole magnetosphere, radiative energy losses and interactions of gamma rays produced by the propagated charged particles with the background radiation field of RIAF. We show that the presence of the vacuum gap has clear observational signatures. The spectra of emission from gaps embedded into a relatively high luminosity RIAF are dominated by the inverse Compton emission with a sharp, super-exponential cut-off in the very-high-energy gamma-ray band. The cut-off energy is determined by the proper...

  20. Electro-Optical Detection of Charged Particle Beams

    CERN Document Server

    Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R C; Lazarus, D M; Magurno, B; Srinivasan-Rao, T; Tsang, Thomas; Usack, V

    1999-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the propagation of laser light in a birefringent crystal at the Brookhaven National Laboratory Accelerator Test Facility. Polarized infrared light was coupled to a LiNbO3 crystal through a polarization maintaining fiber of 4 micron diameter. An electron beam in 10ps bunches of 1mm diameter was scanned across the crystal. The modulation of the laser light during passage of the electron beam was observed using a photodiode with 45GHz bandwidth. The fastest rise time measured, 120ps, was made in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. Both polarization dependent and polarization independent effects were observed. This technology holds promise of greatly improved spatial and temporal resolution of charged particle beams.

  1. Research on laser induced particle acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Raab, Natascha; Buescher, Markus [Institut fuer Kernphysik (IKP), Forschungszentrum Juelich (Germany); Juelich Center for Hadron Physics (JCHP), Forschungszentrum Juelich (Germany); Willi, Oswald; Jung, Ralph [Institut fuer Laser-Plasma Physik (ILPP), Heinrich Heine Universitaet Duesseldorf (Germany); Seltmann, Michael [Institut fuer Kernphysik (IKP), Forschungszentrum Juelich (Germany); FH Aachen (Germany); Juelich Center for Hadron Physics (JCHP), Forschungszentrum Juelich (Germany)

    2009-07-01

    By directing a high-power, ultrashort laser pulse onto a thin foil, it is now possible to produce electron, proton and ion beams. However, for realizing reliable laser-driven accelerators one must still overcome fundamental and technological limitations. One current challenge is to continuously provide mass-limited targets into the laser focus in which its energy can be effectively converted into kinetic energy of the accelerated ions. IKP and ILPP have initiated a corresponding joint project based on a worldwide unique frozen pellet target that can provide a regular flux of frozen spheres of e.g. H2, N2, Ar and Xe, and the 100-TW laser system PULSAR at ILPP. As a first step measurements are carried out with conventional gas and foil targets. These measurements include detector developement for fast particle detection and magnetic focusing of the particle beam as well as optical probing of the plasma itself, in order to better understand the ion-acceleration mechanisms. The talk outlines the status of the research and the results of the first measurements.

  2. Using optical lines to study particle acceleration at supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Morlino, Giovanni [APC, AstroParticule et Cosmologie, Université Paris Diderot, CNRS/IN2P3, CEA/Irfu, Observatoire de Paris, Sorbonne Paris Cité, 10, rue Alice Domon et Léonie Duquet, F-75205 Paris Cedex 13 (France); Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States)

    2014-11-15

    The shocks of several young supernova remnants (SNR) are often associated with very thin optical filaments dominated by Balmer emission resulting from charge-exchange and collisional excitation between neutral Hydrogen from the interstellar medium and shocked protons and electrons. Optical lines are a direct probe of the conditions at the shock, in particular the width of the narrow and broad components reflect the temperature upstream and downstream of the shock, respectively. When the shock accelerate efficiently non-thermal particles, the shock structure changes producing anomalous Balmer lines and it is possible to use their line shape and their spatial profile to check the efficiency of SNR shocks in accelerating cosmic rays. Here we illustrate the kinetic theory of shock acceleration in presence of neutrals with some applications to young SNRs. We show that in three cases (RCW 86, SNR 0509-67.5 and Tycho) anomalous Balmer lines can be explained assuming that a fraction of ∼ 10% of the total shock kinetic energy is converted into not thermal particles, while in one single case, the northwestern part of SN 1006, there is no evidence of efficient acceleration.

  3. Relativistic particle acceleration in developing Alfv\\'{e}n turbulence

    CERN Document Server

    Matsukiyo, S; 10.1088/0004-637X/692/2/1004

    2009-01-01

    A new particle acceleration process in a developing Alfv\\'{e}n turbulence in the course of successive parametric instabilities of a relativistic pair plasma is investigated by utilyzing one-dimensional electromagnetic full particle code. Coherent wave-particle interactions result in efficient particle acceleration leading to a power-law like energy distribution function. In the simulation high energy particles having large relativistic masses are preferentially accelerated as the turbulence spectrum evolves in time. Main acceleration mechanism is simultaneous relativistic resonance between a particle and two different waves. An analytical expression of maximum attainable energy in such wave-particle interactions is derived.

  4. Acceleration Factor Harmonious Particle Swarm Optimizer

    Institute of Scientific and Technical Information of China (English)

    Jie Chen; Feng Pan; Tao Cai

    2006-01-01

    A Particle Swarm Optimizer (PSO) exhibits good performance for optimization problems, although it cannot guarantee convergence to a global, or even local minimum. However, there are some adjustable parameters, and restrictive conditions, which can affect the performance of the algorithm. In this paper, the sufficient conditions for the asymptotic stability of an acceleration factor and inertia weight are deduced, the value of the inertia weight ω is enhanced to (-1, 1).Furthermore a new adaptive PSO algorithm - Acceleration Factor Harmonious PSO (AFHPSO) is proposed, and is proved to be a global search algorithm. AFHPSO is used for the parameter design of a fuzzy controller for a linear motor driving servo system. The performance of the nonlinear model for the servo system demonstrates the effectiveness of the optimized fuzzy controller and AFHPSO.

  5. Formation of Charged Particle Tracks in Solids

    Institute of Scientific and Technical Information of China (English)

    Mukhtar A. Rana

    2006-01-01

    A criterion for formation of etchabJe tracks in solids is suggested using the well-known concepts of ionization and thermal spikes, diffusion process with useful and justified assumptions, and present or published experimental and theoretical investigations on the same subject. The suggested criterion is useful for a wide spectrum of researchers including development and applications of track recording materials, ions implantation, sputtering and other areas, which include interactions of charged particles with solids.

  6. ULF Waves and Diffusive Radial Transport of Charged Particles

    Science.gov (United States)

    Ali, Ashar Fawad

    The Van Allen radiation belts contain highly energetic particles which interact with a variety of plasma and magnetohydrodynamic (MHD) waves. Waves in the ultra low-frequency (ULF) range play an important role in the loss and acceleration of energetic particles. Considering the geometry of the geomagnetic field, charged particles trapped in the inner magnetosphere undergo three distinct types of periodic motions; an adiabatic invariant is associated with each type of motion. The evolution of the phase space density of charged particles in the magnetosphere in the coordinate space of the three adiabatic invariants is modeled by the Fokker-Planck equation. If we assume that the first two adiabatic invariants are conserved while the third invariant is violated, then the general Fokker-Planck equation reduces to a radial diffusion equation with the radial diffusion coefficient quantifying the rate of the radial diffusion of charged particles, including contributions from perturbations in both the magnetic and the electric fields. This thesis investigates two unanswered questions about ULF wave-driven radial transport of charged particles. First, how important are the ULF fluctuations in the magnetic field compared with the ULF fluctuations in the electric field in driving the radial diffusion of charged particles in the Earth's inner magnetosphere? It has generally been accepted that magnetic field perturbations dominate over electric field perturbations, but several recently published studies suggest otherwise. Second, what is the distribution of ULF wave power in azimuth, and how does ULF wave power depend upon radial distance and the level of geomagnetic activity? Analytic treatments of the diffusion coefficients generally assume uniform distribution of power in azimuth, but in situ measurements suggest that this may not be the case. We used the magnetic field data from the Combined Release and Radiation Effects Satellite (CRRES) and the electric and the magnetic

  7. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    Energy Technology Data Exchange (ETDEWEB)

    Geddes, Cameron G.R.; Cormier-Michel, Estelle; Esarey, Eric H.; Schroeder, Carl B.; Vay, Jean-Luc; Leemans, Wim P.; Bruhwiler, David L.; Cary, John R.; Cowan, Ben; Durant, Marc; Hamill, Paul; Messmer, Peter; Mullowney, Paul; Nieter, Chet; Paul, Kevin; Shasharina, Svetlana; Veitzer, Seth; Weber, Gunther; Rubel, Oliver; Ushizima, Daniela; Bethel, Wes; Wu, John

    2009-03-20

    Compared to conventional particle accelerators, plasmas can sustain accelerating fields that are thousands of times higher. To exploit this ability, massively parallel SciDAC particle simulations provide physical insight into the development of next-generation accelerators that use laser-driven plasma waves. These plasma-based accelerators offer a path to more compact, ultra-fast particle and radiation sources for probing the subatomic world, for studying new materials and new technologies, and for medical applications.

  8. A Symplectic Multi-Particle Tracking Model for Self-Consistent Space-Charge Simulation

    CERN Document Server

    Qiang, Ji

    2016-01-01

    Symplectic tracking is important in accelerator beam dynamics simulation. So far, to the best of our knowledge, there is no self-consistent symplectic space-charge tracking model available in the accelerator community. In this paper, we present a two-dimensional and a three-dimensional symplectic multi-particle spectral model for space-charge tracking simulation. This model includes both the effect from external fields and the effect of self-consistent space-charge fields using a split-operator method. Such a model preserves the phase space structure and shows much less numerical emittance growth than the particle-in-cell model in the illustrative examples.

  9. Motion of charged particles in a knotted electromagnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Arrayas, M; Trueba, J L, E-mail: joseluis.trueba@urjc.e [Area de Electromagnetismo, Universidad Rey Juan Carlos, Camino del Molino s/n, 28943 Fuenlabrada, Madrid (Spain)

    2010-06-11

    In this paper we consider the classical relativistic motion of charged particles in a knotted electromagnetic field. After reviewing how to construct electromagnetic knots from maps between the three-sphere and the two-sphere, we introduce a mean quadratic radius of the energy density distribution in order to study some properties of this field. We study the classical relativistic motion of electrons in the electromagnetic field of the Hopf map, and compute their trajectories. It is observed that these electrons initially at rest are strongly accelerated by the electromagnetic force, becoming ultrarelativistic in a period of time that depends on the knot energy and size.

  10. GPU accelerated particle visualization with Splotch

    Science.gov (United States)

    Rivi, M.; Gheller, C.; Dykes, T.; Krokos, M.; Dolag, K.

    2014-07-01

    Splotch is a rendering algorithm for exploration and visual discovery in particle-based datasets coming from astronomical observations or numerical simulations. The strengths of the approach are production of high quality imagery and support for very large-scale datasets through an effective mix of the OpenMP and MPI parallel programming paradigms. This article reports our experiences in re-designing Splotch for exploiting emerging HPC architectures nowadays increasingly populated with GPUs. A performance model is introduced to guide our re-factoring of Splotch. A number of parallelization issues are discussed, in particular relating to race conditions and workload balancing, towards achieving optimal performances. Our implementation was accomplished by using the CUDA programming paradigm. Our strategy is founded on novel schemes achieving optimized data organization and classification of particles. We deploy a reference cosmological simulation to present performance results on acceleration gains and scalability. We finally outline our vision for future work developments including possibilities for further optimizations and exploitation of hybrid systems and emerging accelerators.

  11. Measuring Lagrangian accelerations using an instrumented particle

    CERN Document Server

    Zimmermann, Robert; Gasteuil, Yoann; Volk, Romain; Pinton, Jean-François

    2012-01-01

    Accessing and characterizing a flow impose a number of constraints on the employed measurement techniques; in particular optical methods require transparent fluids and windows in the vessel. Whereas one can adapt apparatus, fluid and methods in the lab to these constraints, this is hardly possible for industrial mixers. We present in this article a novel measurement technique which is suitable for opaque or granular flows: an instrumented particle, which continuously transmits the force/acceleration acting on it as it is advected in a flow. Its density is adjustable for a wide range of fluids and because of its small size and its wireless data transmission, the system can be used both in industrial and scientific mixers allowing a better understanding of the flow within. We demonstrate the capabilities and precision of the particle by comparing its transmitted acceleration to alternative measurements, in particular in the case of a turbulent von K\\'arm\\'an flow. Our technique shows to be an efficient and fast...

  12. Metastable states of plasma particles close to a charged surface

    Energy Technology Data Exchange (ETDEWEB)

    Shavlov, A. V., E-mail: shavlov@ikz.ru [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation); Tyumen State Oil and Gas University, 38, Volodarskogo St., 625000, Tyumen (Russian Federation); Dzhumandzhi, V. A. [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation)

    2015-09-15

    The free energy of the plasma particles and the charged surface that form an electroneutral system is calculated on the basis of the Poisson-Boltzmann equation. It is shown that, owing to correlation of light plasma particles near the charged surface and close to heavy particles of high charge, there can be metastable states in plasma. The corresponding phase charts of metastable states of the separate components of plasma, and plasma as a whole, are constructed. These charts depend on temperature, the charge magnitude, the size of the particles, and the share of the charge of the light carriers out of the total charge of the plasma particles.

  13. Radiation reaction for a massless charged particle

    Science.gov (United States)

    Kazinski, P. O.; Sharapov, A. A.

    2003-07-01

    We derive effective equations of motion for a massless charged particle coupled to the dynamical electromagnetic field with regard to the radiation back reaction. It is shown that unlike the massive case, not all the divergences resulting from the self-action of the particle are Lagrangian, i.e., can be cancelled out by adding appropriate counterterms to the original action. Besides, the order of renormalized differential equations governing the effective dynamics turns out to be greater than the order of the corresponding Lorentz-Dirac equation for a massive particle. For the case of a homogeneous external field, the first radiative correction to the Lorentz equation is explicitly derived via the reduction of order procedure.

  14. Radiation reaction for a massless charged particle

    Energy Technology Data Exchange (ETDEWEB)

    Kazinski, P O; Sharapov, A A [Physics Faculty, Tomsk State University, Tomsk, 634050 (Russian Federation)

    2003-07-07

    We derive effective equations of motion for a massless charged particle coupled to the dynamical electromagnetic field with regard to the radiation back reaction. It is shown that unlike the massive case, not all the divergences resulting from the self-action of the particle are Lagrangian, i.e., can be cancelled out by adding appropriate counterterms to the original action. Besides, the order of renormalized differential equations governing the effective dynamics turns out to be greater than the order of the corresponding Lorentz-Dirac equation for a massive particle. For the case of a homogeneous external field, the first radiative correction to the Lorentz equation is explicitly derived via the reduction of order procedure.

  15. Radiation reaction for a massless charged particle

    CERN Document Server

    Kazinski, P O

    2003-01-01

    We derive effective equations of motion for a massless charged particle coupled to the dynamical electromagnetic field having regard to the radiation back reaction. It is shown that unlike the massive case not all the divergences resulting from the self-action of the particle are Lagrangian, i.e. can be canceled out by adding appropriate counterterms to the original action. Besides, the order of renormalized differential equations governing the effective dynamics turns out to be greater than the order of the corresponding Lorentz-Dirac equation for a massive particle. For the case of homogeneous external field the first radiative correction to the Lorentz equation is explicitly derived via the reduction of order procedure.

  16. PRODUCTION AND APPLICATIONS OF NEUTRONS USING PARTICLE ACCELERATORS

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  17. Production and applications of neutrons using particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Chichester, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  18. A chemical analyzer for charged ultrafine particles

    Directory of Open Access Journals (Sweden)

    S. G. Gonser

    2013-04-01

    Full Text Available New particle formation is a frequent phenomenon in the atmosphere and of major significance for the earth's climate and human health. To date the mechanisms leading to the nucleation of particles as well as to aerosol growth are not completely understood. A lack of appropriate measurement equipment for online analysis of the chemical composition of freshly nucleated particles is one major limitation. We have developed a Chemical Analyzer for Charged Ultrafine Particles (CAChUP capable of analyzing particles with diameters below 30 nm. A bulk of size separated particles is collected electrostatically on a metal filament, resistively desorbed and consequently analyzed for its molecular composition in a time of flight mass spectrometer. We report of technical details as well as characterization experiments performed with the CAChUP. Our instrument was tested in the laboratory for its detection performance as well as for its collection and desorption capabilities. The manual application of known masses of camphene (C10H16 to the desorption filament resulted in a detection limit between 0.5 and 5 ng, and showed a linear response of the mass spectrometer. Flow tube experiments of 25 nm diameter secondary organic aerosol from ozonolysis of alpha-pinene also showed a linear relation between collection time and the mass spectrometer's signal intensity. The resulting mass spectra from the collection experiments are in good agreement with published work on particles generated by the ozonolysis of alpha-pinene. A sensitivity study shows that the current setup of CAChUP is ready for laboratory measurements and for the observation of new particle formation events in the field.

  19. A chemical analyzer for charged ultrafine particles

    Directory of Open Access Journals (Sweden)

    S. G. Gonser

    2013-09-01

    Full Text Available New particle formation is a frequent phenomenon in the atmosphere and of major significance for the Earth's climate and human health. To date the mechanisms leading to the nucleation of particles as well as to aerosol growth are not completely understood. A lack of appropriate measurement equipment for online analysis of the chemical composition of freshly nucleated particles is one major limitation. We have developed a Chemical Analyzer for Charged Ultrafine Particles (CAChUP capable of analyzing particles with diameters below 30 nm. A bulk of size-separated particles is collected electrostatically on a metal filament, resistively desorbed and subsequently analyzed for its molecular composition in a time of flight mass spectrometer. We report on technical details as well as characterization experiments performed with the CAChUP. Our instrument was tested in the laboratory for its detection performance as well as for its collection and desorption capabilities. The manual application of defined masses of camphene (C10H16 to the desorption filament resulted in a detection limit between 0.5 and 5 ng, and showed a linear response of the mass spectrometer. Flow tube experiments of 25 nm diameter secondary organic aerosol from ozonolysis of alpha-pinene also showed a linear relation between collection time and the mass spectrometer's signal intensity. The resulting mass spectra from the collection experiments are in good agreement with published work on particles generated by the ozonolysis of alpha-pinene. A sensitivity study shows that the current setup of CAChUP is ready for laboratory measurements and for the observation of new particle formation events in the field.

  20. Alpha particles diffusion due to charge changes

    Energy Technology Data Exchange (ETDEWEB)

    Clauser, C. F., E-mail: cesar.clauser@ib.edu.ar; Farengo, R. [Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica and Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina)

    2015-12-15

    Alpha particles diffusion due to charge changes in a magnetized plasma is studied. Analytical calculations and numerical simulations are employed to show that this process can be very important in the pedestal-edge-SOL regions. This is the first study that presents clear evidence of the importance of atomic processes on the diffusion of alpha particles. A simple 1D model that includes inelastic collisions with plasma species, “cold” neutrals, and partially ionized species was employed. The code, which follows the exact particle orbits and includes the effect of inelastic collisions via a Monte Carlo type random process, runs on a graphic processor unit (GPU). The analytical and numerical results show excellent agreement when a uniform background (plasma and cold species) is assumed. The simulations also show that the gradients in the density of the plasma and cold species, which are large and opposite in the edge region, produce an inward flux of alpha particles. Calculations of the alpha particles flux reaching the walls or divertor plates should include these processes.

  1. New frontier of laser particle acceleration: driving protons to 80 MeV by radiation pressure

    CERN Document Server

    Kim, I Jong; Kim, Chul Min; Kim, Hyung Taek; Lee, Chang-Lyoul; Choi, Il Woo; Singhal, Himanshu; Sung, Jae Hee; Lee, Seong Ku; Lee, Hwang Woon; Nickles, Peter V; Jeong, Tae Moon; Nam, Chang Hee

    2014-01-01

    The radiation pressure acceleration (RPA) of charged particles has been considered a challenging task in laser particle acceleration. Laser-driven proton/ion acceleration has attracted considerable interests due to its underlying physics and potential for applications such as high-energy density physics, ultrafast radiography, and cancer therapy. Among critical issues to overcome the biggest challenge is to produce energetic protons using an efficient acceleration mechanism. The proton acceleration by radiation pressure is considerably more efficient than the conventional target normal sheath acceleration driven by expanding hot electrons. Here we report the generation of 80-MeV proton beams achieved by applying 30-fs circularly polarized laser pulses with an intensity of 6.1 x 1020 W/cm2 to ultrathin targets. The radiation pressure acceleration was confirmed from the obtained optimal target thickness, quadratic energy scaling, polarization dependence, and 3D-PIC simulations. We expect this fast energy scalin...

  2. A Magnetostrictive Tuning System for Particle Accelerators

    CERN Document Server

    Tai, Chiu-Ying; Daly, Edward; Davis, Kirk; Espinola, William; Han, Zhixiu; Joshi, Chandrashekhar; Mavanur, Anil; Racz, Livia; Shepard, Kenneth

    2005-01-01

    Energen, Inc. has designed, built, and demonstrated several fast and slow tuners based on its magnetostrictive actuators and stepper motor. These tuners are designed for Superconducting Radio Frequency (SRF) cavities, which are important structures in particle accelerators that support a wide spectrum of disciplines, including nuclear and high-energy physics and free electron lasers (FEL). In the past two years, Energen's work has focused on magnetostrictive fast tuners for microphonics and Lorentz detuning compensation on elliptical-cell and spoke-loaded cavities, including the capability for real-time closed-loop control. These tuners were custom designed to meet specific requirements, which included a few to 100 micron stroke range, hundreds to kilohertz operation frequency, and cryogenic temperature operation in vacuum or liquid helium. These tuners have been tested in house and at different laboratories, such as DESY, Argonne National Lab, and Jefferson Lab. Some recent results are presented in this pape...

  3. A Magnetorestrictive Tuning System for Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Chiu-Ying Tai; Jordan Cormier; William Espinola; Zhixiu Han; Chad Joshi; Anil Mavanur; Livia Racz; Kenneth Shepard; Edward Daly; Kirk Davis

    2005-05-16

    Energen, Inc. has designed, built, and demonstrated several fast and slow tuners based on its magnetostrictive actuators and stepper motor. These tuners are designed for Superconducting Radio Frequency (SRF) cavities, which are important structures in particle accelerators that support a wide spectrum of disciplines, including nuclear and high-energy physics and free electron lasers (FEL). In the past two years, Energen's work has focused on magnetostrictive fast tuners for microphonics and Lorentz detuning compensation on elliptical-cell and spoke-loaded cavities. These tuners were custom designed to meet specific requirements, which included a few to 100 micron stroke range, hundreds to kilohertz operation frequency, and cryogenic temperature operation in vacuum or liquid helium. These tuners have been tested in house and at different laboratories, such as DESY, Argonne National Lab, and Jefferson Lab. Some recent results are presented in this paper.

  4. Particle Catcher Using Induced-Charge Electroosmosis

    Science.gov (United States)

    Sugioka, Hideyuki

    2017-01-01

    Finding an innovative separation mechanism is a central task in future microfluidic systems. We propose a size-controllable microfluidic catching device that has a face-to-face structure consisting of elastic beams that change the acceptable particle size dynamically by hydrodynamic force due to induced charge electroosmosis (ICEO) in water and numerically examine the novel separation mechanism consisting of catching and releasing motions with size selectivity. By an implicit strongly coupled simulation technique between a fluid and an elastic structure based on the boundary element method, along with the thin double-layer approximation, we find that the catching device works effectively at low applied voltages in a realistic microfluidic channel and shows a wide range dynamic size selectivity. Furthermore, by modeling the ICEO phenomena with elastic motion, we successfully explain the acceptable particle size of the catching device. We believe that our proposed device will contribute to realizing innovative microfluidic systems in the future.

  5. CVD diamond sensors for charged particle detection

    CERN Document Server

    Krammer, Manfred; Berdermann, E; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Dencuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Koeth, T W; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Perera, L P; Pirollo, S; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Wetstein, M; White, C; Zeuner, W; Zöller, M

    2001-01-01

    CVD diamond material was used to build position-sensitive detectors for single-charged particles to be employed in high-intensity physics experiments. To obtain position information, metal contacts shaped as strips or pixels are applied to the detector surface for one- or two- dimensional coordinate measurement. Strip detectors 2*4 cm/sup 2/ in size with a strip distance of 50 mu m were tested. Pixel detectors of various pixel sizes were bump bonded to electronics chips and investigated. A key issue for the use of these sensors in high intensity experiments is the radiation hardness. Several irradiation experiments were carried out with pions, protons and neutrons exceeding a fluence of 10/sup 15/ particles/cm/sup 2/. The paper presents an overview of the results obtained with strip and pixel detectors in high-energy test beams and summarises the irradiation studies. (8 refs).

  6. Charged Particle Tracking with the Timepix ASIC

    CERN Document Server

    Akiba, Kazuyoshi; Collins, P; Crossley, M; Dumps, R; Gersabeck, M; Gligorov, Vladimir V; Llopart, X; Nicol, M; Poikela, T; Cabruja, Enric; Fleta, C; Lozano, M; Pellegrini, G; Bates, R; Eklund, L; Hynds, D; Ferre Llin, L; Maneuski, D; Parkes, C; Plackett, R; Rodrigues, E; Stewart, G; Akiba, K; van Beuzekom, M; Heijne, V; Heijne, E H M; Gordon, H; John, M; Gandelman, M; Esperante, D; Gallas, A; Vazquez Regueiro, P; Bayer, F; Michel, T; Needham, M; Artuso, M; Badman, R; Borgia, A; Garofoli, J; Wang, J; Xing, Z; Buytaert, Jan; Leflat, Alexander

    2012-01-01

    A prototype particle tracking telescope has been constructed using Timepix and Medipix ASIC hybrid pixel assemblies as the six sensing planes. Each telescope plane consisted of one 1.4 cm2 assembly, providing a 256x256 array of 55 micron square pixels. The telescope achieved a pointing resolution of 2.3 micron at the position of the device under test. During a beam test in 2009 the telescope was used to evaluate in detail the performance of two Timepix hybrid pixel assemblies; a standard planar 300 micron thick sensor, and 285 micron thick double sided 3D sensor. This paper describes a detailed charge calibration study of the pixel devices, which allows the true charge to be extracted, and reports on measurements of the charge collection characteristics and Landau distributions. The planar sensor achieved a best resolution of 4.0 micron for angled tracks, and resolutions of between 4.4 and 11 micron for perpendicular tracks, depending on the applied bias voltage. The double sided 3D sensor, which has signific...

  7. Challenges/issues of NIS used in particle accelerator facilities

    Science.gov (United States)

    Faircloth, Dan

    2013-09-01

    High current, high duty cycle negative ion sources are an essential component of many high power particle accelerators. This talk gives an overview of the state-of-the-art sources used around the world. Volume, surface and charge exchange negative ion production processes are detailed. Cesiated magnetron and Penning surface plasma sources are discussed along with surface converter sources. Multicusp volume sources with filament and LaB6 cathodes are described before moving onto RF inductively coupled volume sources with internal and external antennas. The major challenges facing accelerator facilities are detailed. Beam current, source lifetime and reliability are the most pressing. The pros and cons of each source technology is discussed along with their development programs. The uncertainties and unknowns common to these sources are discussed. The dynamics of cesium surface coverage and the causes of source variability are still unknown. Minimizing beam emittance is essential to maximizing the transport of high current beams; space charge effects are very important. The basic physics of negative ion production is still not well understood, theoretical and experimental programs continue to improve this, but there are still many mysteries to be solved.

  8. Using optical lines to study particle acceleration at supernova remnants

    CERN Document Server

    Morlino, Giovanni

    2014-01-01

    The shocks of several young supernova remnants (SNR) are often associated with very thin optical filaments dominated by Balmer emission resulting from charge-exchange and collisional excitation between neutral Hydrogen from the interstellar medium and shocked protons and electrons. Optical lines are a direct probe of the conditions at the shock, in particular the width of the narrow and broad components reflect the temperature upstream and downstream of the shock, respectively. When the shock accelerate efficiently non-thermal particles, the shock structure changes producing anomalous Balmer lines and it is possible to use their line shape and their spatial profile to check the efficiency of SNR shocks in accelerating cosmic rays. Here we illustrate the kinetic theory of shock acceleration in presence of neutrals with some applications to young SNRs. We show that in three cases (RCW 86, SNR 0509-67.5 and Tycho) anomalous Balmer lines can be explained assuming that a fraction of $\\sim 10\\%$ of the total shock ...

  9. A search for free fractional electric charge elementary particles

    Science.gov (United States)

    Halyo, Valerie

    2001-07-01

    A direct search was carried out in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied-about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 × 10-22 particles per nucleon with 95% confidence.

  10. Search for free fractional electric charge elementary particles

    Energy Technology Data Exchange (ETDEWEB)

    Halyo, V.

    1999-10-29

    The authors have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied--about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 x 10{sup {minus}22} particles per nucleon with 95% confidence.

  11. A Search for Free Fractional Electric Charge Elementary Particles

    Energy Technology Data Exchange (ETDEWEB)

    Halyo, Valerie

    2000-12-04

    A direct search was carried out in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied| about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 x 10{sup -22} particles per nucleon with 95% confidence.

  12. Search for Free Fractional Electric Charge Elementary Particles

    CERN Document Server

    Halyo, V; Lee, E R; Lee, I T; Loomba, D; Perl, Martin Lewis

    2000-01-01

    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied - about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e (e being the magnitude of the electron charge) from the nearest integer charge is less than $4.71\\times10^{-22}$ particles per nucleon with 95% confidence.

  13. A Search for Free Fractional Electric Charge Elementary Particles

    Energy Technology Data Exchange (ETDEWEB)

    Halyo, Valerie

    2000-12-04

    A direct search was carried out in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied--about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 x 10{sup -22} particles per nucleon with 95% confidence.

  14. Proposal of the Electrically Charged Stellar Black Holes as Accelerators of Ultra High Energy Cosmic Rays

    CERN Document Server

    Soto-Manriquez, Jose

    2016-01-01

    A new mechanism for the acceleration of ultra high energy cosmic rays (UHECR) is presented here. It is based on the tunnel-ionization of neutral atoms approaching electrically charged stellar black holes and on the repulsion of the resulting positively charged atomic part by huge, long-range electric fields. Energies above $10^{18}$ eV for these particles are calculated in a simple way by means of this single-shot, all-electrical model. When this acceleration mechanism is combined with the supernova explosions in the galactic halo of the massive runaway stars expelled from the galactic disk, this model predicts nearly the correct values of the measured top energy of the UHECRs and their flux in a specified EeV energy range. It also explains the near isotropy of the arrivals of these energetic particles to Earth, as has been recently measured by the Auger Observatory.

  15. Simulation of ASTROD I test mass charging due to solar energetic particles

    CERN Document Server

    Liu, Lei; Ni, Wei-Tou; Shaul, D N A

    2007-01-01

    As ASTROD I travels through space, its test mass will accrue charge due to galactic cosmic-rays and solar energetic particles incident on the spacecraft. This test mass charge will result in Coulomb forces between the test mass and the surrounding electrodes. In earlier work using the GEANT4 toolkit, we predicted a net charging rate of nearly 9.0 +e/s from cosmic-ray protons between 0.1 and 1000 GeV at solar maximum, and rising to 26.5 +e/s at solar minimum. Here we use GEANT4 to simulate the charging process due to solar energetic particle events and to estimate the magnitude of acceleration noise due to this charging. The predicted charging rates range from 2840 to 64300 +e/s, at peak intensity, for the 4 largest SEP events in September and October 1989. For the 2 larger events, the acceleration disturbances due to charging exceeds the ASTROD I acceleration noise budget requirement. Continuous discharge should be considered for suppressing this charging noise. The acceleration noise during the 2 small event...

  16. Microsparks Generated by Charged Particles in Dielectric Liquids

    Science.gov (United States)

    Geiger, Robert

    2012-10-01

    The electrodynamics of charged particles in dielectric liquids have been described by several authors [1,2]. As a charged particle approaches an electrode of opposite charge the local electric field eventually exceeds the dielectric strength of the liquid and a microspark is generated. These plasmas can be very small, about Angew. Chem., Int. Ed. 47, 8020.

  17. Relative Nonlinear Electrodynamics Interaction of Charged Particles with Strong and Super Strong Laser Fields

    CERN Document Server

    Avetissian, Hamlet

    2006-01-01

    This book covers a large class of fundamental investigations into Relativistic Nonlinear Electrodynamics. It explores the interaction between charged particles and strong laser fields, mainly concentrating on contemporary problems of x-ray lasers, new type small set-up high-energy accelerators of charged particles, as well as electron-positron pair production from super powerful laser fields of relativistic intensities. It will also discuss nonlinear phenomena of threshold nature that eliminate the concurrent inverse processes in the problems of Laser Accelerator and Free Electron Laser, thus creating new opportunities for solving these problems.

  18. Particle trajectories and acceleration during 3D fan reconnection

    CERN Document Server

    Dalla, S; 10.1051/0004-6361:200809771

    2008-01-01

    Context. The primary energy release in solar flares is almost certainly due to magnetic reconnection, making this a strong candidate as a mechanism for particle acceleration. While particle acceleration in 2D geometries has been widely studied, investigations in 3D are a recent development. Two main classes of reconnection regimes at a 3D magnetic null point have been identified: fan and spine reconnection Aims. Here we investigate particle trajectories and acceleration during reconnection at a 3D null point, using a test particle numerical code, and compare the efficiency of the fan and spine regimes in generating an energetic particle population. Methods. We calculated the time evolution of the energy spectra. We discuss the geometry of particle escape from the two configurations and characterise the trapped and escaped populations. Results. We find that fan reconnection is less efficent than spine reconnection in providing seed particles to the region of strong electric field where acceleration is possible...

  19. The Timepix telescope for charged particle tracking

    Science.gov (United States)

    Hynds, Daniel

    2013-12-01

    The Timepix telescope has been developed as a general purpose tool for studying the performance of position sensitive charged particle detectors. Initiated as part of the infrastructure for the development of a new vertex detector for the LHCb experiment, the system was extended under the FP7 project AIDA to allow its use as an external facility by several groups within both the high energy and medical physics communities. Based at the CERN SPS, high track rates (up to 18 kHz), precise spatial resolution at the device under test (down to 1.6 μm), and a flexible integration method have all been demonstrated. The telescope is constructed using the Timepix ASIC, a hybrid pixel chip with an active area of 14×14 mm2.

  20. Enhanced particle acceleration via cascade of autoresonance detrappings

    Energy Technology Data Exchange (ETDEWEB)

    Nakach, R. [Association Euratom-CEA, CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Gell, Y. [CET, Tel-Aviv (Israel)

    1997-10-01

    We propose to enhance the acceleration of electrons by repeating consecutively a basic accelerating mechanism. This mechanism consists of trapping the particles in a traveling ponderomotive well, then autoresonance detrapping them allowing for considerable acceleration. The traveling well is generated by two counterpropagating electromagnetic waves along a uniform magnetic field. (author) 8 refs.

  1. Characterisation of electron beams from laser-driven particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A. [Physics Department, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2012-12-21

    The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.

  2. Beam-driven, Plasma-based Particle Accelerators

    CERN Document Server

    Muggli, P

    2016-01-01

    We briefly give some of the characteristics of the beam-driven, plasma-based particle accelerator known as the plasma wakefield accelerator (PWFA). We also mention some of the major results that have been obtained since the birth of the concept. We focus on high-energy particle beams where possible.

  3. Test-particle acceleration in a hierarchical three-dimensional turbulence model

    Energy Technology Data Exchange (ETDEWEB)

    Dalena, S.; Rappazzo, A. F.; Matthaeus, W. H. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, DE 19716 (United States); Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Greco, A., E-mail: serena.dalena@fis.unical.it [Dipartimento di Fisica, Università della Calabria, I-87036 Cosenza (Italy)

    2014-03-10

    The acceleration of charged particles is relevant to the solar corona over a broad range of scales and energies. High-energy particles are usually detected in concomitance with large energy release events like solar eruptions and flares. Nevertheless, acceleration can occur at smaller scales, characterized by dynamical activity near current sheets. To gain insight into the complex scenario of coronal charged particle acceleration, we investigate the properties of acceleration with a test-particle approach using three-dimensional magnetohydrodynamic (MHD) models. These are obtained from direct solutions of the reduced MHD equations, well suited for a plasma embedded in a strong axial magnetic field, relevant to the inner heliosphere. A multi-box, multiscale technique is used to solve the equations of motion for protons. This method allows us to resolve an extended range of scales present in the system, namely, from the ion inertial scale of the order of a meter up to macroscopic scales of the order of 10 km (1/100th of the outer scale of the system). This new technique is useful to identify the mechanisms that, acting at different scales, are responsible for acceleration to high energies of a small fraction of the particles in the coronal plasma. We report results that describe acceleration at different stages over a broad range of time, length, and energy scales.

  4. Neural Networks for Modeling and Control of Particle Accelerators

    CERN Document Server

    Edelen, A.L.; Chase, B.E.; Edstrom, D.; Milton, S.V.; Stabile, P.

    2016-01-01

    We describe some of the challenges of particle accelerator control, highlight recent advances in neural network techniques, discuss some promising avenues for incorporating neural networks into particle accelerator control systems, and describe a neural network-based control system that is being developed for resonance control of an RF electron gun at the Fermilab Accelerator Science and Technology (FAST) facility, including initial experimental results from a benchmark controller.

  5. A highly-segmented ΔE-time-of-flight wall as forward detector of the 4π-system for charged particles at the SIS/ESR accelerator

    Science.gov (United States)

    Gobbi, A.; Alard, J. P.; Augustinski, G.; Basrak, Z.; Bastid, N.; Belayev, I. M.; Blaich, Th.; Boccaccio, P.; Bock, R.; Boussange, S.; Buta, A.; Čaplar, R.; Cerruti, C.; Charity, R. J.; Cindro, N.; Coffin, J. P.; Crouau, M.; Daudon, F.; Devin, J. F.; Dupieux, P.; Erö, J.; Fan, Z. G.; Fayard, C.; Fintz, P.; Fodor, Z.; Fraysse, L.; Freifelder, R.; Frolov, S.; Gimenez, E.; Grigorian, Y.; Guillaume, G.; Herrmann, N.; Hildenbrand, K. D.; Hölbling, S.; Hornecker, F.; Houari, A.; Jeong, S. C.; Jorio, M.; Jundt, F.; Kecskeméti, J.; Koncz, P.; Korchagin, Y.; Kotte, R.; Krämer, M.; Kuhn, C.; Lebedev, A.; Legrand, I.; Maguire, C. F.; Manko, V.; Marquardt, M.; Matulewicz, T.; Mayade, S.; Mgebrishvili, G.; Mösner, J.; Moisa, D.; Montarou, G.; Montbel, I.; Morel, P.; Neubert, W.; Neunlist, R.; Ortlepp, G.; Pelte, D.; Petrovici, M.; Rami, F.; Reisdorf, W.; Saettel, M. A.; Sahuc, E.; Savinel, G.; Seres, Z.; Schüll, D.; Sikora, B.; Simion, V.; Smolyankin, S.; Sodan, U.; Tanaka, M. H.; Teh, K. M.; Tezkratt, R.; Tischler, B.; Trzaska, M.; Vasiliev, M. A.; Vincent, D.; Wagner, P.; Weinert, J.; Wessels, J. P.; Wienold, T.; Wilhelmi, Z.; Wohlfarth, D.; Zhilin, A. V.

    1993-01-01

    At the SIS/ESR accelerator facility at GSI in Darmstadt the 4π-detector system FOPI is under construction at present. It is designed for the investigation of central collisions of heavy ions in the energy range up to 2 A GeV. As phase I of this detector a forward wall has been built and used in various experiments. It comprizes a total number of 764 scintillators with an additional shell of 188 thin ΔE-detectors in front of it and covers the full azimuth of the polar angles from 1° to 30°. The velocity and the nuclear charge of the fragments are determined by a combined time-of-flight and ΔE measurement.

  6. A highly-segmented [Delta]E-time-of-flight wall as forward detector of the 4[pi]-system for charged particles at the SIS/ESR accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Gobbi, A.; Augustinski, G.; Bock, R.; Charity, R.J.; Fan, Z.G.; Freifelder, R.; Hildenbrand, K.D.; Jeong, S.C.; Marquardt, M.; Reisdorf, W.; Schuell, D.; Sodan, U.; Tanaka, M.H.; Teh, K.M.; Weinert, J.; Wessels, J.P. (Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany)); Alard, J.P.; Bastid, N.; Boussange, S.; Crouau, M.; Daudon, F.; Dupieux, P.; Fayard, C.; Fraysse, L.; Jorio, M.; Mayade, S.; Montarou, G.; Montbel, I.; Morel, P.; Sahuc, E.; Savinel, G.; Vincent, D. (Lab. de Physique Corpusculaire, Univ. Clermont-Ferrand, Aubiere (France)); Basrak, Z.; Caplar, R.; Cindro, N.; Hoelbling, S. (Rudjer Boskovic Inst., Zagreb (Croatia)); Belayev, I.M.; Frolov, S.; Korchagin, Y.; Lebedev, A.; Smolyankin, S.; Zhilin, A.V. (Inst. for Experimental and Theoretical Physics, Moscow (Russia)); Blaich, T. (Inst. fuer Kernchemie, Univ. Mainz (Germany)); Boccaccio, P. (Ist. Nazionale di Fisica Nucleare, Lab. Nazionali Legnaro, Padua (Italy)); Buta, A.; Legrand, I.; Moisa, D.; Petrovici, M

    1993-01-01

    At the SIS/ESR accelerator facility at GSI in Darmstadt the 4[pi]-detector system FOPI is under construction at present. It is designed for the investigation of central collisions of heavy ions in the energy range up to 2 A GeV. As phase I of this detector a forward wall has been built and used in various experiments. It comprizes a total number of 764 scintillators with an additional shell of 188 thin [Delta]E-detectors in front of it and covers the full azimuth of the polar angles from 1deg to 30deg. The velocity and the nuclear charge of the fragments are determined by a combined time-of-flight and [Delta]E measurements. (orig.).

  7. Searches for Fractionally Charged Particles: What Should Be Done Next?

    Energy Technology Data Exchange (ETDEWEB)

    Perl, Martin L.; /SLAC

    2009-01-15

    Since the initial measurements of the electron charge a century ago, experimenters have faced the persistent question as to whether elementary particles exist that have charges that are fractional multiples of the electron charge. I concisely review the results of the last 50 years of searching for fractional charge particles with no confirmed positive results. I discuss the question of whether more searching is worthwhile?

  8. Inertial-particle accelerations in turbulence: a Lagrangian closure

    CERN Document Server

    Vajedi, S; Mehlig, B; Biferale, L

    2016-01-01

    The distribution of particle accelerations in turbulence is intermittent, with non-Gaussian tails that are quite different for light and heavy particles. In this article we analyse a closure scheme for the acceleration fluctuations of light and heavy inertial particles in turbulence, formulated in terms of Lagrangian correlation functions of fluid tracers. We compute the variance and the flatness of inertial particle accelerations and we discuss their dependency on the Stokes number. The closure incorporates effects induced by the Lagrangian correlations along the trajectories of fluid tracers, and its predictions agree well with results of direct numerical simulations of inertial particles in turbulence, provided that the effects induced by the inertial preferential sampling of heavy/light particles outside/inside vortices are negligible. In particular, the scheme predicts the correct functional behaviour of the acceleration variance, as a function of Stokes, as well as the presence of a minimum/maximum for ...

  9. Search for Free Fractional Electric Charge Elementary Particles

    OpenAIRE

    Halyo, V.; Kim, P.; Lee, E. R.; Lee, I T; Loomba, D.; Perl, M. L.

    1999-01-01

    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied - about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e (e being the magnitude of the electron charge) from the nearest integer charge is less than $4.71\\times...

  10. Effects of charged particles on human tumor cells

    Directory of Open Access Journals (Sweden)

    Kathryn D Held

    2016-02-01

    Full Text Available The use of charged particle therapy in cancer treatment is growing rapidly, in large part because the exquisite dose localization of charged particles allows for higher radiation doses to be given to tumor tissue while normal tissues are exposed to lower doses and decreased volumes of normal tissues are irradiated. In addition, charged particles heavier than protons have substantial potential clinical advantages because of their additional biological effects including greater cell killing effectiveness, decreased radiation resistance of hypoxic cells in tumors and reduced cell cycle dependence of radiation response. These biological advantages depend on many factors such as endpoint, cell or tissue type, dose, dose rate or fractionation, charged particle type and energy, and oxygen concentration. This review summarizes the unique biological advantages of charged particle therapy and highlights recent research and areas of particular research needs, such as quantification of Relative Biological Effectiveness (RBE for various tumor types and radiation qualities, role of genetic background of tumor cells in determining response to charged particles, sensitivity of cancer stem-like cells to charged particles, role of charged particles in tumors with hypoxic fractions and importance of fractionation, including use of hypofractionation, with charged particles.

  11. Charged and Neutral Particles Channeling Phenomena Channeling 2008

    Science.gov (United States)

    Dabagov, Sultan B.; Palumbo, Luigi

    2010-04-01

    On the discovery of coherent Bremsstrahlung in a single crystal at the Frascati National Laboratories / C. Barbiellini, G. P. Murtas and S. B. Dabagov -- Advances in coherent Bremsstrahlung and LPM-effect studies (to the lOOth anniversary from the birth of L. D. Landau) / N. F. Shul'ga -- Spectra of radiation and created particles at intermediate energy in oriented crystal taking into account energy loss / V. N. Baier and V. M. Katkov -- The coherent Bremsstrahlung beam at MAX-lab facility / K. Fissum ... [et al.] -- Radiation from thin, structured targets (CERN NA63) / A. Dizdar -- Hard incoherent radiation in thick crystals / N. F. Shul'ga, V. V. Syshchenko and A. I. Tarnovsky -- Coherent Bremsstrahlung in periodically deformed crystals with a complex base / A. R. Mkrtchyan, A. A. Saharian and V. V. Parazian -- Induction of coherent x-ray Bremsstrahlung in crystals under the influence of acoustic waves / A. R. Mkrtchyan and V. V. Parazian -- Coherent processes in bent single crystals / V. A. Maisheev -- Experimental and theoretical investigation of complete transfer phenomenon for media with various heat exchange coefficients / A. R. Mkrtchyan, A. E. Movsisyan and V. R. Kocharyan -- Coherent pair production in crystals / A. R. Mkrtchyan, A. A. Saharian and V. V. Parazian -- Negative particle planar and axial channeling and channeling collimation / R. A. Carrigan, Jr. -- CERN crystal-based collimation in modern hadron colliders / W. Scandale -- Studies and application of bent crystals for beam steering at 70 GeV IHEP accelerator / A. G. Afonin ... [et al.] -- Crystal collimation studies at the Tevatron (T-980) / N. V. Mokhov ... [et al.] -- Fabrication of crystals for channeling of particles in accellerators / A. Mazzolari ... [et al.] -- New possibilities to facilitate collimation of both positively and negatively charged particle beams by crystals / V. Guidi, A. Mazzolari and V. V. Tikhomirov -- Increase of probability of particle capture into the channeling

  12. Particle accelerations and current structures of Weibel and Filamentation instabilities

    Science.gov (United States)

    Ryu, C. M.; Huynh, C. T.

    2015-12-01

    Particle accelerations of the Wibel instability (WI) and the Filamentation instability(FI) are studied by using PIC simuations, comparing them side-by-side. Although two instabilities are almost identical in the linear growth phase, significant differences are found in the nonlinear phase in their particle accelerations and current structures. The FI shows enhanced electron acceleration, whereas particle acceleration is almost absent in the WI. The different particle accelerations between the FI and the WI seem to be associated with their different current structures; a hollow electron current structure for the FI and a center filled current structure for that of the WI. Different electron distributions seem to bring in different current filament structures, eventually leading to different magnetic characteristics.

  13. Time-dependent particle acceleration in a Fermi reservoir

    Science.gov (United States)

    Litvinenko, Y. E.

    2012-08-01

    Context. A steady model was presented by Burn, in which energy conservation is used to constrain the parameters of stochastic Fermi acceleration. A steady model, however, is unlikely to be adequate for particle acceleration in impulsive solar flares. Aims: This paper describes a time-dependent model for particle acceleration in a Fermi reservoir Methods: The calculation is based on the original formulation of stochastic acceleration by Fermi, with additional physically motivated assumptions about the turbulent and particle energy densities within the reservoir, that are similar to those of the steady analysis. The problem is reduced to an integro-differential equation that possesses an analytical solution. Results: The model predicts the formation of a power-law differential energy spectrum N(E) ~ E-2, that is observable outside the reservoir. The predicted spectral index is independent of the parameters of the model. The results may help in understanding particle acceleration in solar flares and other astrophysical applications.

  14. Large bulk matter search for fractional charge particles

    CERN Document Server

    Lee, I

    2002-01-01

    We have carried out the largest search for stable particles with fractional electric charge, based on an oil drop method that incorporates a horizontal electric field and upward air flow. No evidence for such particles was found, giving a 95% C.L. upper limit of $1.15\\times 10^{-22}$ particles per nucleon on the abundance of fractional charge particles in silicone oil for $0.18 e \\le |Q_{residual}| \\le 0.82 e$.

  15. Revisiting Acceleration of Charged Grains in Magnetohydrodynamic Turbulence

    CERN Document Server

    Hoang, Thiem; Schlickeiser, R

    2011-01-01

    We study the acceleration of charged grains by magnetohydrodynamics (MHD) turbulence in the interstellar medium (ISM). We begin with revisiting gyroresonance acceleration by taking into account fluctuations of the grain guiding center along a uniform magnetic field (i.e. non-linear theory, NLT). We calculate grain velocity due to gyroresonance acceleration by fast modes using the NLT for different phases of the ISM, and compare with results obtained using quasi-linear theory (QLT). We find that the fluctuations of the grain guiding center reduce the grain velocity by less than 15 percent, but large grains are still accelerated to super-Alfvenic speed. For such super-Alfvenic grains, we investigate the effect of transit time damping (TTD) by fast modes. We find that due to the broadening of resonance condition in the NLT, the TTD acceleration is not only important for the cosine pitch angle $\\mu>V_{A}/v$, but also for $\\mu

  16. Hollow-Core Photonic Band Gap Fibers for Particle Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Noble, Robert J.; Spencer, James E.; /SLAC; Kuhlmey, Boris T.; /Sydney U.

    2011-08-19

    Photonic band gap (PBG) dielectric fibers with hollow cores are being studied both theoretically and experimentally for use as laser driven accelerator structures. The hollow core functions as both a longitudinal waveguide for the transverse-magnetic (TM) accelerating fields and a channel for the charged particles. The dielectric surrounding the core is permeated by a periodic array of smaller holes to confine the mode, forming a photonic crystal fiber in which modes exist in frequency pass-bands, separated by band gaps. The hollow core acts as a defect which breaks the crystal symmetry, and so-called defect, or trapped modes having frequencies in the band gap will only propagate near the defect. We describe the design of 2-D hollow-core PBG fibers to support TM defect modes with high longitudinal fields and high characteristic impedance. Using as-built dimensions of industrially-made fibers, we perform a simulation analysis of the first prototype PBG fibers specifically designed to support speed-of-light TM modes.

  17. Acceleration and Particle Field Interactions of Cosmic Rays II: Calculations

    CERN Document Server

    Tawfik, A; Ghoneim, M T; Hady, A

    2010-01-01

    Based on the generic acceleration model, which suggests different types of electromagnetic interactions between the cosmic charged particles and the different configurations of the electromagnetic (plasma) fields, the ultra high energy cosmic rays are studied. The plasma fields are assumed to vary, spatially and temporally. The well-known Fermi accelerations are excluded. Seeking for simplicity, it is assumed that the energy loss due to different physical processes is negligibly small. The energy available to the plasma sector is calculated in four types of electromagnetic fields. It has been found that the drift in a time--varying magnetic field is extremely energetic. The energy scale widely exceeds the Greisen-Zatsepin-Kuzmin (GZK) cutoff. The polarization drift in a time--varying electric field is also able to raise the energy of cosmic rays to an extreme value. It can be compared with the Hillas mechanism. The drift in a spatially--varying magnetic field is almost as strong as the polarization drift. The...

  18. Test particle acceleration in a numerical MHD experiment of an anemone jet

    CERN Document Server

    Rosdahl, Karl Joakim

    2010-01-01

    To use a 3D numerical MHD experiment representing magnetic flux emerging into an open field region as a background field for tracing charged particles. The interaction between the two flux systems generates a localised current sheet where MHD reconnection takes place. We investigate how efficiently the reconnection region accelerates charged particles and what kind of energy distribution they acquire. The particle tracing is done numerically using the Guiding Center Approximation on individual data sets from the numerical MHD experiment. We derive particle and implied photon distribution functions having power law forms, and look at the impact patterns of particles hitting the photosphere. We find that particles reach energies far in excess of those seen in observations of solar flares. However the structure of the impact region in the photosphere gives a good representation of the topological structure of the magnetic field.

  19. Electron Beam Charge Diagnostics for Laser Plasma Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Smith, Alan; Rodgers, David; Donahue, Rich; Byrne, Warren; Leemans, Wim

    2011-06-27

    A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). First, a scintillating screen (Lanex) was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT) for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/(ps mm{sup 2}), respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within {+-}8%, showing that they all can provide accurate charge measurements for LPAs.

  20. Interaction of free charged particles with a chirped electromagnetic pulse

    NARCIS (Netherlands)

    Khachatryan, A.G.; Goor, van F.A.; Boller, K.-J.

    2004-01-01

    We study the effect of chirp on electromagnetic (EM) pulse interaction with a charged particle. Both the one-dimensional (1D) and 3D cases are considered. It is found that, in contrast to the case of a nonchirped pulse, the charged particle energy can be changed after the interaction with a 1D EM ch

  1. Abnormal Kinetic Energy of Charged Dust Particles in Plasmas

    NARCIS (Netherlands)

    Norman, G.; Stegailov, V.; Timofeev, A.

    2010-01-01

    A mechanism of the increase of the average kinetic energy of charged dust particles in gas discharge plasmas is suggested. Particle charge fluctuation is the reason for the appearance of forced resonance, which heals vertical oscillations. The energy transfer from vertical oscillations to the horizo

  2. Peculiarities of propagation of charged particles in solar corona

    Science.gov (United States)

    Morozova, E. I.; Pisarenko, N. F.; Mikryukova, N. A.; Klimenko, V. V.; Timofeev, V. E.; Shafer, Y. G.

    1985-01-01

    The influence of boundaries of the large scale unipolar magnetic regions (UMR) on the Sun upon the charged particle propagation in the solar corona and interplanetary space is investigated. Increases of the charged particle fluxes from solar flares on November 4 and 20, 1978 detected by Venera-11 and Prognoz-1 and on December 7, 1982 by Venera-13 and "GMS-2" were analyzed.

  3. Fractional dynamics of charged particles in magnetic fields

    Science.gov (United States)

    Coronel-Escamilla, A.; Gómez-Aguilar, J. F.; Alvarado-Méndez, E.; Guerrero-Ramírez, G. V.; Escobar-Jiménez, R. F.

    2016-02-01

    In many physical applications the electrons play a relevant role. For example, when a beam of electrons accelerated to relativistic velocities is used as an active medium to generate Free Electron Lasers (FEL), the electrons are bound to atoms, but move freely in a magnetic field. The relaxation time, longitudinal effects and transverse variations of the optical field are parameters that play an important role in the efficiency of this laser. The electron dynamics in a magnetic field is a means of radiation source for coupling to the electric field. The transverse motion of the electrons leads to either gain or loss energy from or to the field, depending on the position of the particle regarding the phase of the external radiation field. Due to the importance to know with great certainty the displacement of charged particles in a magnetic field, in this work we study the fractional dynamics of charged particles in magnetic fields. Newton’s second law is considered and the order of the fractional differential equation is (0;1]. Based on the Grünwald-Letnikov (GL) definition, the discretization of fractional differential equations is reported to get numerical simulations. Comparison between the numerical solutions obtained on Euler’s numerical method for the classical case and the GL definition in the fractional approach proves the good performance of the numerical scheme applied. Three application examples are shown: constant magnetic field, ramp magnetic field and harmonic magnetic field. In the first example the results obtained show bistability. Dissipative effects are observed in the system and the standard dynamic is recovered when the order of the fractional derivative is 1.

  4. Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

    CERN Document Server

    Zharkova, Valentina V; Benz, Arnold O; Browning, Phillippa; Dauphin, Cyril; Emslie, A Gordon; Fletcher, Lyndsay; Kontar, Eduard P; Mann, Gottfried; Onofri, Marco; Petrosian, Vahe; Turkmani, Rim; Vilmer, Nicole; Vlahos, Loukas

    2011-01-01

    We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.

  5. Particle Accelerators and Detectors for medical Diagnostics and Therapy

    CERN Document Server

    Braccini, Saverio

    2016-01-01

    This Habilitationsschrift (Habilitation thesis) is focused on my research activities on medical applications of particle physics and was written in 2013 to obtain the Venia Docendi (Habilitation) in experimental physics at the University of Bern. It is based on selected publications, which represented at that time my major scientific contributions as an experimental physicist to the field of particle accelerators and detectors applied to medical diagnostics and therapy. The thesis is structured in two parts. In Part I, Chapter 1 presents an introduction to accelerators and detectors applied to medicine, with particular focus on cancer hadrontherapy and on the production of radioactive isotopes. In Chapter 2, my publications on medical particle accelerators are introduced and put into their perspective. In particular, high frequency linear accelerators for hadrontherapy are discussed together with the new Bern cyclotron laboratory. Chapter 3 is dedicated to particle detectors with particular emphasis on three ...

  6. An improved limit on the charge of antihydrogen from stochastic acceleration

    Science.gov (United States)

    Ahmadi, M.; Baquero-Ruiz, M.; Bertsche, W.; Butler, E.; Capra, A.; Carruth, C.; Cesar, C. L.; Charlton, M.; Charman, A. E.; Eriksson, S.; Evans, L. T.; Evetts, N.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Isaac, C. A.; Ishida, A.; Jones, S. A.; Jonsell, S.; Kurchaninov, L.; Madsen, N.; Maxwell, D.; McKenna, J. T. K.; Menary, S.; Michan, J. M.; Momose, T.; Munich, J. J.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Rasmussen, C. Ø.; Robicheaux, F.; Sacramento, R. L.; Sameed, M.; Sarid, E.; Silveira, D. M.; So, C.; Tharp, T. D.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Zhmoginov, A. I.

    2016-01-01

    Antimatter continues to intrigue physicists because of its apparent absence in the observable Universe. Current theory requires that matter and antimatter appeared in equal quantities after the Big Bang, but the Standard Model of particle physics offers no quantitative explanation for the apparent disappearance of half the Universe. It has recently become possible to study trapped atoms- of antihydrogen to search for possible, as yet unobserved, differences in the physical behaviour of matter and antimatter. Here we consider the charge neutrality of the antihydrogen atom. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of |Q| < 0.71 parts per billion (one standard deviation), in which e is the elementary charge. This bound is a factor of 20 less than that determined from the best previous measurement of the antihydrogen charge. The electrical charge of atoms and molecules of normal matter is known to be no greater than about 10-21e for a diverse range of species including H2, He and SF6. Charge-parity-time symmetry and quantum anomaly cancellation demand that the charge of antihydrogen be similarly small. Thus, our measurement constitutes an improved limit and a test of fundamental aspects of the Standard Model. If we assume charge superposition and use the best measured value of the antiproton charge, then we can place a new limit on the positron charge anomaly (the relative difference between the positron and elementary charge) of about one part per billion (one standard deviation), a 25-fold reduction compared to the current best measurement.

  7. GALACTIC AND EXTRAGALACTIC SUPERNOVA REMNANTS AS SITES OF PARTICLE ACCELERATION

    Directory of Open Access Journals (Sweden)

    Manami Sasaki

    2013-12-01

    Full Text Available Supernova remnants, owing to their strong shock waves, are likely sources of Galactic cosmic rays. Studies of supernova remnants in X-rays and gamma rays provide us with new insights into the acceleration of particles to high energies. This paper reviews the basic physics of supernova remnant shocks and associated particle acceleration and radiation processes. In addition, the study of supernova remnant populations in nearby galaxies and the implications for Galactic cosmic ray distribution are discussed.

  8. Safety guidance and inspection program for particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Do Whey [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of); Lee, Hee Seock; Yeo, In Whan [Pohang Accelerator Laboratory, Pohang (Korea, Republic of)] (and others)

    2001-03-15

    The inspection program and the safety guidance were developed to enhance the radiation protection for the use of particle accelerators. First the classification of particle accelerators was conducted to develop the safety inspection protocol efficiently. The status of particle accelerators which were operated at the inside and outside of the country, and their safety programs were surveyed. The characteristics of radiation production was researched for each type of particle accelerators. Two research teams were launched for industrial and research accelerators and for medical accelerators, respectively. In each stages of a design, a fabrication, an installation, a commissioning, and normal operation of accelerators, those safety inspection protocols were developed. Because all protocols resulted from employing safety experts, doing the questionnaire, and direct facility surveys, it can be applicable to present safety problem directly. The detail improvement concepts were proposed to revise the domestic safety rule. This results might also be useful as a practical guidance for the radiation safety officer of an accelerator facility, and as the detail standard for the governmental inspection authorities.

  9. Dust particle charge distribution in a stratified glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Sukhinin, Gennady I [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Fedoseev, Alexander V [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Ramazanov, Tlekkabul S [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Dzhumagulova, Karlygash N [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Amangaliyeva, Rauan Zh [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan)

    2007-12-21

    The influence of a highly pronounced non-equilibrium characteristic of the electron energy distribution function in a stratified dc glow discharge on the process of dust particle charging in a complex plasma is taken into account for the first time. The calculated particle charge spatial distribution is essentially non-homogeneous and it can explain the vortex motion of particles at the periphery of a dusty cloud obtained in experiments.

  10. Accelerating research into the Higgs boson particle

    CERN Multimedia

    Nikolaidou, Rosy

    "The only Standard Model particle yet to be observed, the search for the Higgs Boson - the so-called 'God Particle' - demands advanced facilities and physics expertise. At the Cern laboratory in Switzerland, the ARTEMIS project is well-placed to pursue research in this area" (2 pages)

  11. Particle acceleration by fluctuating electric fields at a magnetic field null point

    CERN Document Server

    Petkaki, P

    2007-01-01

    Particle acceleration consequences from fluctuating electric fields superposed on an X-type magnetic field in collisionless solar plasma are studied. Such a system is chosen to mimic generic features of dynamic reconnection, or the reconnective dissipation of a linear disturbance. We explore numerically the consequences for charged particle distributions of fluctuating electric fields superposed on an X-type magnetic field. Particle distributions are obtained by numerically integrating individual charged particle orbits when a time varying electric field is superimposed on a static X-type neutral point. This configuration represents the effects of the passage of a generic MHD disturbance through such a system. Different frequencies of the electric field are used, representing different possible types of wave. The electric field reduces with increasing distance from the X-type neutral point as in linear dynamic magnetic reconnection. The resulting particle distributions have properties that depend on the ampli...

  12. Physical Interpretation of the Schott Energy of An Accelerating Point Charge and the Question of Whether a Uniformly Accelerating Charge Radiates

    Science.gov (United States)

    Rowland, David R.

    2010-01-01

    A core topic in graduate courses in electrodynamics is the description of radiation from an accelerated charge and the associated radiation reaction. However, contemporary papers still express a diversity of views on the question of whether or not a uniformly accelerating charge radiates suggesting that a complete "physical" understanding of the…

  13. Charged Particle ID with DIRCs in PANDA at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Schepers, Georg [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Collaboration: PANDA Cherenkov Group of the PANDA-Collaboration

    2015-07-01

    The PANDA detector at FAIR, the new international accelerator facility for antiprotons and ions in Darmstadt, will address open questions of hadronic physics. Experiments concerning charmonium spectroscopy are performed with antiproton beams colliding with hydrogen or nuclear targets. The beam momentum range between 1.5 GeV/c and 15 GeV/c allows tests of the predictions by perturbation theory, but will also reveal deviations originating from strong QCD. Excellent charged particle identification over a large momentum range is necessary for all these experiments. In the target spectrometer this will be accomplished by two Cherenkov counters using the DIRC principle, reducing the size of the solenoid and calorimeter. Both counters have to work in a strong magnetic field and withstand high event rates. The concept of the Barrel DIRC, covering the polar angles between 22 and 140 degrees, is based on the successful BaBar DIRC. It uses focusing optics with lenses and fast photon timing. The Endcap Disc DIRC works with a novel radiator geometry and covers the angular range from 5 to 22 degrees. In addition to a fast electronic readout it employs a compact photon detection system. Prototypes were tested with particle beams at GSI, CERN, DESY, and MAMI to validate the design choices. The results achieved and the status of the PANDA DIRC detectors are presented.

  14. Particle Acceleration and Heating by Turbulent Reconnection

    Science.gov (United States)

    Vlahos, Loukas; Pisokas, Theophilos; Isliker, Heinz; Tsiolis, Vassilis; Anastasiadis, Anastasios

    2016-08-01

    Turbulent flows in the solar wind, large-scale current sheets, multiple current sheets, and shock waves lead to the formation of environments in which a dense network of current sheets is established and sustains “turbulent reconnection.” We constructed a 2D grid on which a number of randomly chosen grid points are acting as scatterers (i.e., magnetic clouds or current sheets). Our goal is to examine how test particles respond inside this large-scale collection of scatterers. We study the energy gain of individual particles, the evolution of their energy distribution, and their escape time distribution. We have developed a new method to estimate the transport coefficients from the dynamics of the interaction of the particles with the scatterers. Replacing the “magnetic clouds” with current sheets, we have proven that the energization processes can be more efficient depending on the strength of the effective electric fields inside the current sheets and their statistical properties. Using the estimated transport coefficients and solving the Fokker-Planck (FP) equation, we can recover the energy distribution of the particles only for the stochastic Fermi process. We have shown that the evolution of the particles inside a turbulent reconnecting volume is not a solution of the FP equation, since the interaction of the particles with the current sheets is “anomalous,” in contrast to the case of the second-order Fermi process.

  15. Particle Acceleration in Relativistic Jets Due to Weibel Instability

    Science.gov (United States)

    Nishikawa, K.-I.; Hardee, P.; Richardson, G.; Preece, R.; Sol, H.; Fishman, G. J.

    2004-01-01

    Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a three-dimensional relativistic electromagnetic particle code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. While some Fermi acceleration may occur at the jet front, the majority of electron acceleration takes place behind the jet front and cannot be characterized as Fermi acceleration. The simulation results show that this instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields, which contribute to the electron s transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  16. Cavitation Inception on Microparticles: A Self-Propelled Particle Accelerator

    DEFF Research Database (Denmark)

    Arora, M.; Ohl, C.-D.; Mørch, Knud Aage

    2004-01-01

    Corrugated, hydrophilic particles with diameters between 30 and 150 mum are found to cause cavitation inception at their surfaces when they are exposed to a short, intensive tensile stress wave. The growing cavity accelerates the particle into translatory motion until the tensile stress decreases...

  17. Grid Connected Power Supplies for Particle Accelerator Magnets

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup

    and smaller converter size. A high efficiency converter based on Silicon Carbide switching devices is also presented exhibiting above 96 % efficiency for the entire power range. Finally reliability issues are considered as the reliability of a particle accelerator supply is of utmost importance. Particle...

  18. Double layer -- a particle accelerator in the magnetosphere

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Xiangrong [Los Alamos National Laboratory

    2015-07-16

    Slides present the material under the following topics: Introduction (What is a double layer (DL)? Why is it important? Key unsolved problems); Theory -- time-independent solutions of 1D Vlasov--Poisson system; Particle-in-cell simulations (Current-driven DLs); and Electron acceleration by DL (Betatron acceleration). Key problems include the generation mechanism, stability, and electron acceleration. In summary, recent observations by Van Allen Probes show large number of DLs in the outer radiation belt, associated with enhanced flux of relativistic electrons. Simulations show that ion acoustic double layers can be generated by field-aligned currents. Thermal electrons can gain energy via betatron acceleration in a dipole magnetic field.

  19. The Maximum Energy of Accelerated Particles in Relativistic Collisionless Shocks

    CERN Document Server

    Sironi, Lorenzo; Arons, Jonathan

    2013-01-01

    The afterglow emission from gamma-ray bursts (GRBs) is usually interpreted as synchrotron radiation from electrons accelerated at the GRB external shock, that propagates with relativistic velocities into the magnetized interstellar medium. By means of multi-dimensional particle-in-cell simulations, we investigate the acceleration performance of weakly magnetized relativistic shocks, in the magnetization range 0particle accelerators if the magnetization is sigma<1e-3. For electron-ion plasmas, the transition to efficient acceleration occurs for sigma<3e-5. Here, the acceleration process proceeds similarly for the two species, since the electrons enter the shock nearly in equipartition with the ions, as a result of strong pre-heating in the self-generated upstream turbulence. In both...

  20. Search for charged-particle emission from deuterated palladium foils

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, K.D.; Gippner, P.; Seidel, W.; Stary, F.; Wohlfarth, D. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic))

    1990-05-01

    Results are presented from the search for energetic charged particles possibly emitted from a deuterium loaded palladium electrode in an electrolysis cell. Within the sensitivity of our experimental set-up, we could not find events originating from 'cold nuclear fusion' processes. Based on this outcome, an upper limit for the non-observation of CNF of 2.0x10{sup -2}s{sup -1} emitted charged particles per cm{sup 3} (Pd) resp. 1.6x10{sup -24}s{sup -1} emitted charged particles per D pair has been deduced. (orig.).

  1. Accelerated lifetime testing of energy storage capacitors used in particle accelerators power converters

    CERN Document Server

    AUTHOR|(SzGeCERN)679542; Genton, Charles-Mathieu

    2015-01-01

    Energy storage capacitors are used in large quantities in high power converters for particle accelerators. In this application capacitors see neither a DC nor an AC voltage but a combination of the two. The paper presents a new power converter explicitly designed to perform accelerated testing on these capacitors and the results of the tests.

  2. Advanced visualization technology for terascale particle accelerator simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ma, K-L; Schussman, G.; Wilson, B.; Ko, K.; Qiang, J.; Ryne, R.

    2002-11-16

    This paper presents two new hardware-assisted rendering techniques developed for interactive visualization of the terascale data generated from numerical modeling of next generation accelerator designs. The first technique, based on a hybrid rendering approach, makes possible interactive exploration of large-scale particle data from particle beam dynamics modeling. The second technique, based on a compact texture-enhanced representation, exploits the advanced features of commodity graphics cards to achieve perceptually effective visualization of the very dense and complex electromagnetic fields produced from the modeling of reflection and transmission properties of open structures in an accelerator design. Because of the collaborative nature of the overall accelerator modeling project, the visualization technology developed is for both desktop and remote visualization settings. We have tested the techniques using both time varying particle data sets containing up to one billion particle s per time step and electromagnetic field data sets with millions of mesh elements.

  3. Particle accelerators inside spinning black holes.

    Science.gov (United States)

    Lake, Kayll

    2010-05-28

    On the basis of the Kerr metric as a model for a spinning black hole accreting test particles from rest at infinity, I show that the center-of-mass energy for a pair of colliding particles is generically divergent at the inner horizon. This shows not only that classical black holes are internally unstable, but also that Planck-scale physics is a characteristic feature within black holes at scales much larger that the Planck length. The novel feature of the divergence discussed here is that the phenomenon is present only for black holes with rotation, and in this sense it is distinct from the well-known Cauchy horizon instability.

  4. Search for Fractional-Charge Particles in Meteoritic Material

    Science.gov (United States)

    Kim, Peter C.; Lee, Eric R.; Lee, Irwin T.; Perl, Martin L.; Halyo, Valerie; Loomba, Dinesh

    2007-10-01

    We have used an automated Millikan oil drop method to search for free fractional-charge particles in a sample containing in total 3.9 mg of pulverized Allende meteorite suspended in 259 mg of mineral oil. The average diameter of the drops was 26.5μm with the charge on about 42 500 000 drops being measured. This search was motivated by the speculation that isolatable, fractional-charge particles produced in the early Universe and present in our Solar System are more likely to be accumulated in asteroids than on Earth‘s surface. No evidence for fractional-charge particles was found. With 95% confidence, the concentration of particles with fractional-charge more than 0.25 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 1.3×10-21 particles per nucleon in the meteoritic material and less than 1.9×10-23 particles per nucleon in the mineral oil.

  5. On the possibility of accelerating multiply charged ions in the CERN Synchrocyclotron

    CERN Document Server

    Giannini, R

    1975-01-01

    Some problems relating to the possibility of accelerating light ions in the CERN SC are studied. Deuteron capture conditions and the optimum radio-frequency versus time curve are calculated. Internal beam currents of some micro-amperes seem obtainable when using the calutron source as for protons. The same calculations were repeated for N/sup 5+/ taking into account the charge exchange process in the vacuum. A transmission of between 5 and 10% has been calculated, giving some 10/sup 10/ particles per second with a PIG source.

  6. PARALLEL 3-D SPACE CHARGE CALCULATIONS IN THE UNIFIED ACCELERATOR LIBRARY.

    Energy Technology Data Exchange (ETDEWEB)

    D' IMPERIO, N.L.; LUCCIO, A.U.; MALITSKY, N.

    2006-06-26

    The paper presents the integration of the SIMBAD space charge module in the UAL framework. SIMBAD is a Particle-in-Cell (PIC) code. Its 3-D Parallel approach features an optimized load balancing scheme based on a genetic algorithm. The UAL framework enhances the SIMBAD standalone version with the interactive ROOT-based analysis environment and an open catalog of accelerator algorithms. The composite package addresses complex high intensity beam dynamics and has been developed as part of the FAIR SIS 100 project.

  7. Studies on mechanisms of the laser particle acceleration; Untersuchungen zu Mechanismen der Laser-Teilchenbeschleunigung

    Energy Technology Data Exchange (ETDEWEB)

    Aurand, Bastian

    2012-06-20

    Within the last decade, many developments towards higher energies and particle numbers paved the way of particle acceleration performed by high intensity laser systems. Up to now, the process of a field-induced acceleration process (Target-Normal-Sheath-Acceleration (TNSA)) is investigated the most. Acceleration occurs as a consequence of separation of charges on a surface potential. Here, the broad energy spectrum is a problem not yet overcome although many improvements were achieved. Calculations for intensities higher than 10{sup 20..21} W/cm{sup 2} give hint that Radiation-Pressure-Acceleration (RPA) may lead to a sharper, monoenergetic energy spectrum. Within the framework of this thesis, the investigation of the acceleration mechanism is studied experimentally in the intensity range of 10{sup 19} W/cm{sup 2}. Suitable targets were developed and applied for patent. A broad range of parameters was scanned by means of high repetition rates together with an adequate laser system to provide high statistics of several thousands of shots, and the dependence of target material, intensity, laser polarisation and pre plasma-conditions was verified. Comparisons with 2-d numeric simulations lead to a model of the acceleration process which was analyzed by several diagnostic methods, giving clear evidence for a new, not field-induced acceleration process. In addition, a system for a continuous variation of the polarization based on reflective optics was developed in order to overcome the disadvantages of retardation plates, and their practicability of high laser energies can be achieved.

  8. The influence of filler particles on space charge measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hole, Stephane [Laboratoire des Instruments et Systemes d' Ile de France, Universite Pierre et Marie Curie - 10, rue Vauquelin, 75005 Paris, France (France); Sylvestre, Alain [Laboratoire d' lectrostatique et des Materiaux Dielectriques, CNRS UMR5517 - 25, avenue des Martyrs, BP 166, 38042 Grenoble Cedex 9 (France); Rowe, Stephen [Direction des Recherches Materiaux, Schneider Electric SA - 20, rue Henri Tarze, 38050 Grenoble Cedex (France)

    2004-07-07

    The effects of filler particles on the signal measured using the pressure-wave-propagation method to determine the space charge distribution are analysed. A special test sample geometry is used to classify the influence of particles, and in particular, the role of piezoelectricity is discussed. Applications with Epoxy resin samples loaded either by silica or alumina particles are presented. Silica particles are shown to exhibit piezoelectricity which strongly modifies the measured signals.

  9. Charged particle propagation through nanostructures and associated radiation

    Institute of Scientific and Technical Information of China (English)

    N.K.ZHEVAGO; V.I.GLEBOV

    2004-01-01

    In this report, using computer simulations, we investigate the channeling of high-energy charged particles in nanotube ropes and fullerites and estimate the capability of bent nanocrystals to deflect a particle beam. We also discuss electromagnetic radiation arising both from the non-uniform motion of the particles in the electrostatic potential of aligned atoms and from the transient polarization of the medium caused by the particles.

  10. Calculation Methodology and Fabrication Procedures for Particle Accelerator Strip-Line Kickers: Application to the CTF3 Combiner Ring Extraction Kicker and TL2 Tail Clippers

    OpenAIRE

    Rodriguez Garcia, Iker

    2014-01-01

    A particle accelerator is any device that, using electromagnetic fields, is able to communicate energy to charged particles (typically electrons or ionized atoms), accelerating and/or energizing them up to the required level for its purpose. The applications of particle accelerators are countless, beginning in a common TV CRT, passing through medical X-ray devices, and ending in large ion colliders utilized to find the smallest details of the matter. Among the other engineering applications, ...

  11. Calculation Methodology and Fabrication Procedures for Particle Accelerator Strip-Line Kickers: Application to the CTF3 Combiner Ring Extraction Kicker and TL2 Tail Clippers

    OpenAIRE

    Rodriguez Garcia, Iker

    2009-01-01

    A particle accelerator is any device that, using electromagnetic fields, is able to communicate energy to charged particles (typically electrons or ionized atoms), accelerating and/or energizing them up to the required level for its purpose. The applications of particle accelerators are countless, beginning in a common TV CRT, passing through medical X-ray devices, and ending in large ion colliders utilized to find the smallest details of the matter. Among the other engineering applications, ...

  12. Charged particle interaction with a chirped electromagnetic pulse

    NARCIS (Netherlands)

    Khachatryan, A.G.; Boller, K.-J.; Goor, van F.A.

    2003-01-01

    It is found that a charged particle can get a net energy gain from the interaction with an electromagnetic chirped pulse. Theoretically, the energy gain increases with the pulse amplitude and with the relative frequency variation in the pulse.

  13. Radiobiology with heavy charged particles: a historical review

    Energy Technology Data Exchange (ETDEWEB)

    Skarsgard, L.D. [Dept. of Medical Biophysics, B.C. Cancer Research Centre and TRIUMF, Vancouver (Canada)

    1997-09-01

    The presentation will attempt to briefly review some of radiobiological data on the effects of heavy charged particles and to discuss the influence of those studies on the clinical application which followed. (orig./MG)

  14. GPU Accelerated Particle Visualization with Splotch

    CERN Document Server

    Rivi, Marzia; Krokos, Mel; Dolag, Klaus; Reinecke, Martin

    2013-01-01

    Splotch is a rendering algorithm for exploration and visual discovery in particle-based datasets coming from astronomical observations or numerical simulations. The strengths of the approach are production of high quality imagery and support for very large-scale datasets through an effective mix of the OpenMP and MPI parallel programming paradigms. This article reports our experiences in re-designing Splotch for exploiting emerging HPC architectures nowadays increasingly populated with GPUs. A performance model is introduced for data transfers, computations and memory access, to guide our re-factoring of Splotch. A number of parallelization issues are discussed, in particular relating to race conditions and workload balancing, towards achieving optimal performances. Our implementation was accomplished by using the CUDA programming paradigm. Our strategy is founded on novel schemes achieving optimized data organisation and classification of particles. We deploy a reference simulation to present performance res...

  15. Proposal to Search for Magnetically Charged Particles with Magnetic Charge 1e

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Michael K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fryberger, David [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-11-02

    A model for composite elementary Standard Model (SM) particles based upon magnetically bound vorton pairs, we briefly introduce here, predicts the existence of a complete family of magnetically charged particles, as well as their neutral isotopic partners (all counterparts to the SM elementary particles), in which the lowest mass (charged) particle would be an electrically neutral stable lepton, but which carries a magnetic charge equivalent to 1e. This new particle, which we call a magneticon (a counterpart to the electron) would be pair produced at all e+e- colliders at an Ecm above twice its mass. In addition, PP and PPbar colliders should also be able to produce these new particles through the Drell-Yan process. To our knowledge, no monopole search experiment has been sensitive to such a low-charged magnetic monopole above a particle mass of about 5 GeV/c2. Hence, we propose that a search for such a stable particle of magnetic charge 1e should be undertaken. We have taken the ATLAS detector at the LHC as an example in which this search might be done. To this end, we modeled the magnetic fields and muon trigger chambers of this detector. We show results from a simple Monte Carlo simulation program to indicate how these particles might look in the detector and describe how one might search for these new particles in the ATLAS data stream.

  16. Reduction of surface charges during coalescence of elastomer particles.

    Science.gov (United States)

    Gauer, Cornelius; Wu, Hua; Morbidelli, Massimo

    2010-07-15

    Reaction-limited aggregation of soft elastomer particles has been studied with specific attention to the fate of surface charges during coalescence. The employed system is an aqueous dispersion of fluoroelastomer particles, which are known to coalesce completely at 70 degrees C. In contrast to diffusion-limited conditions, under reaction-limited conditions the stability of the system is expected to change during aggregation because of surface reduction and charge accumulation resulting from coalescence. This allows investigating the mechanism of charge relocation during cluster coalescence. For particles stabilized by ionic surfactants, it has been found that the charges are mobile (i.e., they redistribute between aqueous solution and particle surface according to their adsorption equilibrium) (Gauer, C.; Jia, Z.; Wu, H.; Morbidelli, M. Langmuir 2009, 25, 9703). In this work, we consider the case of fixed charges, as those given by charged polymer end groups covalently bound to the particle surface. We demonstrate that a loss of fixed surface charges occurs during the coalescence and strongly affects the time evolution and the shape of the resulting cluster mass distribution.

  17. Noncommutative magnetic moment of charged particles

    CERN Document Server

    Adorno, T C; Shabad, A E; Vassilevich, D V

    2011-01-01

    It has been argued, that in noncommutative field theories sizes of physical objects cannot be taken smaller than an elementary length related to noncommutativity parameters. By gauge-covariantly extending field equations of noncommutative U(1)_*-theory to the presence of external sources, we find electric and magnetic fields produces by an extended charge. We find that such a charge, apart from being an ordinary electric monopole, is also a magnetic dipole. By writing off the existing experimental clearance in the value of the lepton magnetic moments for the present effect, we get the bound on noncommutativity at the level of 10^4 TeV.

  18. An improved search for elementary particles with fractional electric charge

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.R.

    1996-08-01

    The SLAC Quark Search Group has demonstrated successful operation of a low cost, high mass throughput Millikan apparatus designed to search for fractionally charged particles. About six million silicone oil drops were measured with no evidence of fractional charges. A second experiment is under construction with 100 times greater throughput which will utilize optimized search fluids.

  19. Engines of discovery a century of particle accelerators

    CERN Document Server

    Sessler, Andrew

    2014-01-01

    Particle accelerators exploit the cutting edge of every aspect of today's technology and have themselves contributed to many of these technologies. The largest accelerators have been constructed as research tools for nuclear and high energy physics and there is no doubt that it is this field that has sustained their development culminating in the Large Hadron Collider. An earlier book by the same authors, Engines of Discovery: A Century of Particle Accelerators chronicled the development of these large accelerators and colliders, emphasizing the critical discoveries in applied physics and engineering that drove the field. Particular attention was given to the key individuals who contributed, the methods they used to arrive at their particular discoveries and inventions, often recalling how their human strengths and attitudes may have contributed to their achievements. Much of this historical picture is also to be found, little changed, in Part A of this sequel. Since the first book was written it has become ...

  20. Observation of High Iron Charge States at Low Energies in Solar Energetic Particle Events

    Science.gov (United States)

    Guo, Z.; Möbius, E.; Klecker, B.; Bochsler, P.; Connell, J. J.; Kartavykh, Y. Y.; Mason, G. M.; Popecki, M. A.

    2014-04-01

    The ionic charge states of solar energetic particles (SEPs) provide direct information about the source plasma, the acceleration environment, and their transport. Recent studies report that both gradual and impulsive SEP events show mean iron charge states langQ Ferang ~ 10-14 at low energies E nuc-1, consistent with their origin from typical corona material at temperatures 1-2 MK. Observed increases of langQ Ferang up to 20 at energies 0.1-0.5 MeV nuc-1 in impulsive SEPs are attributed to stripping during acceleration. However, Q Fe > 16 is occasionally found in the solar wind, particularly coming from active regions, in contrast to the exclusively reported langQ Ferang = 14 throughout the entire SEPICA and STOF energy range have been identified. Four of the nine events are impulsive events identified through velocity dispersion that are consistent with source temperatures >=2 MK up to ~4 MK. The other five events show evidence of interplanetary acceleration. Four of them involve re-acceleration of impulsive material, whose original energy dependent charge states appear re-distributed to varying extent bringing higher charge states to lower energy. One event, which shows flat but elevated langQ Ferang ~ 14.2 over the entire energy range, can be associated with interplanetary acceleration of high temperature material. This event may exemplify a rare situation when a second shock plows through high temperature coronal mass ejection material.

  1. Colloidal gelation of oppositely charged particles

    NARCIS (Netherlands)

    Russel, E.; Sprakel, J.H.B.; Kodger, T.E.; Weitz, D.A.

    2012-01-01

    Colloidal gelation has been extensively studied for the case of purely attractive systems, but little is understood about how colloidal gelation is affected by the presence of repulsive interactions. Here we demonstrate the gelation of a binary system of oppositely charged colloids, in which repulsi

  2. Cyclotron resonant interactions in cosmic particle accelerators

    CERN Document Server

    Terasawa, T; 10.1007/s11214-012-9878-0

    2012-01-01

    A review is given for cyclotron resonant interactions in space plasmas. After giving a simple formulation for the test particle approach, illustrative examples for resonant interactions are given. It is shown that for obliquely propagating whistler waves, not only fundamental cyclotron resonance, but also other resonances, such as transit-time resonance, anomalous cyclotron resonance, higher-harmonic cyclotron resonance, and even subharmonic resonance can come into play. A few recent topics of cyclotron resonant interactions, such as electron injection in shocks, cyclotron resonant heating of solar wind heavy ions, and relativistic modifications, are also reviewed.

  3. Schwarzschild black hole as particle accelerator of spinning particles

    CERN Document Server

    Zaslavskii, O B

    2016-01-01

    It is shown that in the Schwarzschild background there exists direct counterpart of the Ba\\~{n}ados-Silk-West effect for spinning particles. This means that if two particles collide near the black hole horizon, their energy in the centre of mass frame can grow unbound. In doing so, the crucial role is played by so-called near-critical trajectories when particle's parameters are almost fine-tuned. Direct scenario of the collision under discussion is possible with restriction on the energy-to-mass ratio \\thinspace $E/m<\\frac{1}{2\\sqrt{3}}$ only. However, if one takes into account multiple scattering, this becomes possible for $E\\geq m$ as well.

  4. Hysteresis effects in the cores of particle accelerator magnets

    CERN Document Server

    AUTHOR|(CDS)2086181; Schoerling, Daniel

    A study of the hysteresis effects in the cores of particle accelerator magnets has been performed in the framework of the work presented in this thesis. This study has been focused on normal conducting particle accelerator magnets whose cores are manufactured using ferromagnetic materials. The magnetic circuits have been modelled using the developed models: one model for the magnetic circuit and one for the magnetization of the material in the core. The parameters of the magnetic circuit model have been identified with the help of simulations which rely on the finite element method (Opera 3D), while the parameters of the magnetic hysteresis model have been identified through experimental measurements performed using a method developed in the framework of this work. The modelling results have been validated by means of experimental measurements performed on two magnets: one small size magnet which has been specifically designed and manufactured, and one magnet which is currently used in a particle accelerator ...

  5. FIRST-ORDER PARTICLE ACCELERATION IN MAGNETICALLY DRIVEN FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Beresnyak, Andrey [Naval Research Laboratory, Washington, DC 20375 (United States); Li, Hui [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2016-03-10

    We demonstrate that particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. Some examples of such flows include spontaneous turbulent reconnection and decaying magnetohydrodynamic turbulence, where a magnetic field relaxes to a lower-energy configuration and transfers part of its energy to kinetic motions of the fluid. We show that this energy transfer, which normally causes turbulent cascade and heating of the fluid, also results in a first-order acceleration of non-thermal particles. Since it is generic, this acceleration mechanism is likely to play a role in the production of non-thermal particle distribution in magnetically dominant environments such as the solar chromosphere, pulsar magnetospheres, jets from supermassive black holes, and γ-ray bursts.

  6. Medical physics--particle accelerators--the beginning.

    Science.gov (United States)

    Ganz, Jeremy C

    2014-01-01

    This chapter outlines the early development of particle accelerators with the redesign from linear accelerator to cyclotron by Ernest Lawrence with a view to reducing the size of the machines as the power increased. There are minibiographies of Ernest Lawrence and his brother John. The concept of artificial radiation is outlined and the early attempts at patient treatment are mentioned. The reasons for trying and abandoning neutron therapy are discussed, and the early use of protons is described.

  7. Is the 3-D magnetic null point with a convective electric field an efficient particle accelerator?

    Science.gov (United States)

    Guo, J.-N.; Büchner, J.; Otto, A.; Santos, J.; Marsch, E.; Gan, W.-Q.

    2010-04-01

    Aims: We study the particle acceleration at a magnetic null point in the solar corona, considering self-consistent magnetic fields, plasma flows and the corresponding convective electric fields. Methods: We calculate the electromagnetic fields by 3-D magnetohydrodynamic (MHD) simulations and expose charged particles to these fields within a full-orbit relativistic test-particle approach. In the 3-D MHD simulation part, the initial magnetic field configuration is set to be a potential field obtained by extrapolation from an analytic quadrupolar photospheric magnetic field with a typically observed magnitude. The configuration is chosen so that the resulting coronal magnetic field contains a null. Driven by photospheric plasma motion, the MHD simulation reveals the coronal plasma motion and the self-consistent electric and magnetic fields. In a subsequent test particle experiment the particle energies and orbits (determined by the forces exerted by the convective electric field and the magnetic field around the null) are calculated in time. Results: Test particle calculations show that protons can be accelerated up to 30 keV near the null if the local plasma flow velocity is of the order of 1000 km s-1 (in solar active regions). The final parallel velocity is much higher than the perpendicular velocity so that accelerated particles escape from the null along the magnetic field lines. Stronger convection electric field during big flare explosions can accelerate protons up to 2 MeV and electrons to 3 keV. Higher initial velocities can help most protons to be strongly accelerated, but a few protons also run the risk to be decelerated. Conclusions: Through its convective electric field and due to magnetic nonuniform drifts and de-magnetization process, the 3-D null can act as an effective accelerator for protons but not for electrons. Protons are more easily de-magnetized and accelerated than electrons because of their larger Larmor radii. Notice that macroscopic MHD

  8. Studying astrophysical particle acceleration with laser-driven plasmas

    Science.gov (United States)

    Fiuza, Frederico

    2016-10-01

    The acceleration of non-thermal particles in plasmas is critical for our understanding of explosive astrophysical phenomena, from solar flares to gamma ray bursts. Particle acceleration is thought to be mediated by collisionless shocks and magnetic reconnection. The microphysics underlying these processes and their ability to efficiently convert flow and magnetic energy into non-thermal particles, however, is not yet fully understood. By performing for the first time ab initio 3D particle-in-cell simulations of the interaction of both magnetized and unmagnetized laser-driven plasmas, it is now possible to identify the optimal parameters for the study of particle acceleration in the laboratory relevant to astrophysical scenarios. It is predicted for the Omega and NIF laser conditions that significant non-thermal acceleration can occur during magnetic reconnection of laser-driven magnetized plasmas. Electrons are accelerated by the electric field near the X-points and trapped in contracting magnetic islands. This leads to a power-law tail extending to nearly a hundred times the thermal energy of the plasma and that contains a large fraction of the magnetic energy. The study of unmagnetized interpenetrating plasmas also reveals the possibility of forming collisionless shocks mediated by the Weibel instability on NIF. Under such conditions, both electrons and ions can be energized by scattering out of the Weibel-mediated turbulence. This also leads to power-law spectra that can be detected experimentally. The resulting experimental requirements to probe the microphysics of plasma particle acceleration will be discussed, paving the way for the first experiments of these important processes in the laboratory. As a result of these simulations and theoretical analysis, there are new experiments being planned on the Omega, NIF, and LCLS laser facilities to test these theoretical predictions. This work was supported by the SLAC LDRD program and DOE Office of Science, Fusion

  9. Understanding the Acceleration of Energetic Particles at the Termination Shock

    Science.gov (United States)

    Gloeckler, G.; Fisk, L. A.

    2006-05-01

    Voyager 1 observations of energetic particles during the crossing of the Termination Shock of the solar wind present a number of puzzles, and challenges to existing acceleration theories. For example, downstream from the shock the low-energy phase space density spectra are power laws exhibiting a remarkably constant spectral index, which is difficult to understand in terms of standard diffusive shock acceleration. Upstream from the shock there are beams of highly anisotropic energetic particles, with varying spectral shapes. Again, diffusive shock acceleration has difficultly in dealing with such large anisotropies. Here we show that the observed, constant spectral index of -5 can be accounted for by a simple theory in which the pressure in the accelerated particles behaves according to the Rankine-Hugoniot relationship of an ideal gas at the shock. We also demonstrate that the observed varying spectral shapes of the upstream beams result from velocity dispersion of a downstream spectrum with index of -5 propagating along magnetic flux tubes connecting the termination shock to Voyager 1. We show that even though the beams dominate the upstream foreshock region, they do not have an appreciable effect on the shock acceleration process. The implications of our theory for the acceleration of the Anomalous Cosmic Rays in the heliosheath are also discussed.

  10. Particle-fluid interaction forces as the source of acceleration PDF invariance in particle size

    CERN Document Server

    Meller, Yosef

    2014-01-01

    The conditions allowing particle suspension in turbulent flow are of interest in many applications, but understanding them is complicated both by the nature of turbulence and by the interaction of flow with particles. Observations on small particles indicate an invariance of acceleration PDFs of small particles independent of size. We show to be true the postulated role of particle/fluid interaction forces in maintaining suspension. The 3D-PTV method, applied for two particle phases (tracers and inertial particles) simultaneously, was used to obtain velocity and acceleration data, and through the use of the particle's equation of motion the magnitude of forces representing either the flow or the particle interaction were derived and compared. The invariance of PDFs is shown to extend to the component forces, and lift forces are shown to be significant.

  11. Stochastic particle acceleration and statistical closures

    Energy Technology Data Exchange (ETDEWEB)

    Dimits, A.M.; Krommes, J.A.

    1985-10-01

    In a recent paper, Maasjost and Elsasser (ME) concluded, from the results of numerical experiments and heuristic arguments, that the Bourret and the direct-interaction approximation (DIA) are ''of no use in connection with the stochastic acceleration problem'' because (1) their predictions were equivalent to that of the simpler Fokker-Planck (FP) theory, and (2) either all or none of the closures were in good agreement with the data. Here some analytically tractable cases are studied and used to test the accuracy of these closures. The cause of the discrepancy (2) is found to be the highly non-Gaussian nature of the force used by ME, a point not stressed by them. For the case where the force is a position-independent Ornstein-Uhlenbeck (i.e., Gaussian) process, an effective Kubo number K can be defined. For K << 1 an FP description is adequate, and conclusion (1) of ME follows; however, for K greater than or equal to 1 the DIA behaves much better qualitatively than the other two closures. For the non-Gaussian stochastic force used by ME, all common approximations fail, in agreement with (2).

  12. Technical training: AXEL-2012 - Introduction to Particle Accelerators

    CERN Multimedia

    HR Department

    2011-01-01

    CERN Technical Training 2012: Learning for the LHC! AXEL-2012 is a course series on particle accelerators, given at CERN within the framework of the Technical Training Program. Being part of BE Department’s Operation Group Shutdown Lecture series, the general accelerator physics module is organized since 2003 as a joint venture between the BE Department and Technical Training, and is open to a wider CERN community. The AXEL-2012 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge on accelerators. However, some basic knowledge on trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) from the 16th – 20th of January 2012, and given in English with ...

  13. METHODOLOGICAL NOTES: Radiation damping forces and radiation from charged particles

    Science.gov (United States)

    Klepikov, N. P.

    1985-06-01

    A review of the literature on the radiation reaction force on a charged particle shows that the expression given for this force obtained by Lorentz, Abraham, and Dirac is in physically reasonable agreement with the radiation of energy, momentum, and angular momentum, and is successfully used in investigating the motion of particles in a field. A selection of physical solutions by the methods presented herein guarantees that the conservation laws are satisfied. In the first approximation, which is the only one utilized in the majority of physical situations, radiation damping does not depend on assumptions concerning the structure of the charge of the particle. A theory is presented of the losses of energy, momentum and angular momentum by a system of charged particles in the course of their moving together taking into account the external field, the radiation damping forces, and the retarded Lienard-Wiechert forces. Formulas are given for the spectral and angular distribution of the radiation from a system of particles. The concept of a center of a system of events with relativistic particles is utilized in constructing a system of equations for finding the angular momenta of the electromagnetic waves radiated by particles of the system. The angular distribution and the total intensity of the radiation from a system of particles at an arbitrary instant of time is obtained. Using the example of the joint synchrotron radiation from two particles the consistency of all three approaches to the radiation from a system of particles is demonstrated.

  14. Radiation from an Accelerated Point Charge and Non-Inertial Observers

    Science.gov (United States)

    Leonov, A. B.

    2012-01-01

    It is known that observers comoving with a uniformly accelerated point charge detect the electromagnetic field of a charge as a static electric field. We show that one can find a similar family of observers, which detect the field of a charge as a static electric field, in the general case of arbitrary point-charge motion. We find the velocities…

  15. Charge Balance in the Mesosphere with Meteoric Dust Particles

    Science.gov (United States)

    Robertson, S. H.; Asmus, H.; Dickson, S.; Friedrich, M.; Megner, L. S.

    2013-12-01

    An aerosol particle charging model developed initially for noctilucent cloud particles has been extended in several steps in order to better explain data for charged meteoric smoke particles (MSPs) returned by the nighttime and daytime CHAMPS rockets launched from the Andøya rocket Range, Norway, in October 2011. Addition of photodetachment to the model shows that this process reduces the number density of positively charged MSPs as well as the number density of negatively charged MSPs as a consequence of the photodetached electrons neutralizing the positively charged MSPs. In addition, the model shows that the ionization rate can be deduced from the electron number density and the electron-ion recombination rate only at the highest altitudes as a consequence of recombination of electrons on the MSPs at lower altitudes. The differences between the daytime and nighttime data place constraints on the photodetachment rate. A further extension of the model to include the formation of negative ions and their destruction by atomic oxygen helps explain the ledge seen in the number density of the lightest negatively charged particles. MSP particle densities from the CARMA/CHEM2D model are in better agreement with rocket data for assumed values of the meteor input flux that are at the low end of the generally accepted range.

  16. Particle acceleration at shocks - A Monte Carlo method

    Science.gov (United States)

    Kirk, J. G.; Schneider, P.

    1987-01-01

    A Monte Carlo method is presented for the problem of acceleration of test particles at relativistic shocks. The particles are assumed to diffuse in pitch angle as a result of scattering off magnetic irregularities frozen into the fluid. Several tests are performed using the analytic results available for both relativistic and nonrelativistic shock speeds. The acceleration at relativistic shocks under the influence of radiation losses is investigated, including the effects of a momentum dependence in the diffusion coefficient. The results demonstrate the usefulness of the technique in those situations in which the diffusion approximation cannot be employed, such as when relativistic bulk motion is considered, when particles are permitted to escape at the boundaries, and when the effects of the finite length of the particle mean free path are important.

  17. Determination of Beam Intensity and Position in a Particle Accelerator

    CERN Document Server

    Kasprowicz, Grzegorz; Raich, Uli

    2011-10-04

    A subject of the thesis is conception, design, implementation, tests and deployment of new position measurement system of particle bunch in the CERN PS circular accelerator. The system is based on novel algorithms of particle position determination. The Proton Synchrotron accelerator (PS), installed at CERN†, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC)‡. The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajectory and orbit measurement system of the PS is dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam posi...

  18. Determination of beam intensity and position in a particle accelerator

    CERN Document Server

    Kasprowicz, G

    2011-01-01

    A subject of the thesis is conception, design, implementation, tests and deployment of new position measurement system of particle bunch in the CERN PS circular accelerator. The system is based on novel algorithms of particle position determination. The Proton Synchrotron accelerator (PS), installed at CERN, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC). The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajectory and orbit measurement system of the PS is dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam position monitors...

  19. Charged-particle orbits near a magnetic null point

    OpenAIRE

    Jaroensutasinee, K.; Rowlands, G.

    2000-01-01

    An approximate analytical expression is obtained for the orbits of a charged particle moving in a cusp magnetic field. The particle orbits pass close to or through a region of zero magnetic field before being reflected in regions where the magnetic field is strong. Comparison with numerically evaluated orbits shows that the analytical formula is surprisingly good and captures all the main features of the particle motion. A map describing the long-time behaviour of such orbits is obtained.

  20. Late time CMB anisotropies constrain mini-charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, C.; Redondo, J.; Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Jaeckel, J. [Univ. of Durham, Inst. for Particle Physics Phenomenology (United Kingdom)

    2009-09-15

    Observations of the temperature anisotropies induced as light from the CMB passes through large scale structures in the late universe are a sensitive probe of the interactions of photons in such environments. In extensions of the Standard Model which give rise to mini-charged particles, photons propagating through transverse magnetic fields can be lost to pair production of such particles. Such a decrement in the photon flux would occur as photons from the CMB traverse the magnetic fields of galaxy clusters. Therefore late time CMB anisotropies can be used to constrain the properties of mini- charged particles. We outline how this test is constructed, and present new constraints on mini-charged particles from observations of the Sunyaev-Zel'dovich effect in the Coma cluster. (orig.)

  1. Case Studies in Space Charge and Plasma Acceleration of Charged Beams

    CERN Document Server

    Bazzani, A; Londrillo, P; Sinigardi, S; Turchetti, G

    2014-01-01

    Plasma acceleration with electron or proton driver beams is a challenging opportunity for high energy physics. An energy doubling experiment with electron drivers was successfully performed at SLAC and a key experiment AWAKE with proton drivers is on schedule at CERN. Simulations play an important role in choosing the best experimental conditions and in interpreting the results. The Vlasov equation is the theoretical tool to describe the interaction of a driver particle beam or a driver laser pulse with a plasma. Collective effects, such as tune shift and mismatch instabilities, appear in high intensity standard accelerators and are described by the Poisson-Vlasov equation. In the paper we review the Vlasov equation in electrostatic and fully electromagnetic case. The general framework of variational principles is used to derive the equation, the local form of the balance equations and related conservation laws. In the electrostatic case we remind the analytic Kapchinskij-Vladimirskij (K-V) model and we propo...

  2. Particle acceleration in cosmic plasmas – paradigm change?

    Energy Technology Data Exchange (ETDEWEB)

    Lytikov, Maxim [Purdue University; Guo, Fan [Los Alamos National Laboratory

    2015-07-21

    The presentation begins by considering the requirements on the acceleration mechanism. It is found that at least some particles in high-energy sources are accelerated by magnetic reconnection (and not by shocks). The two paradigms can be distinguished by the hardness of the spectra. Shocks typically produce spectra with p > 2 (relativistic shocks have p ~ 2.2); non-linear shocks & drift acceleration may give p < 2, e.g. p=1.5; B-field dissipation can give p = 1. Then collapse of stressed magnetic X-point in force-free plasma and collapse of a system of magnetic islands are taken up, including Island merger: forced reconnection. Spectra as functions of sigma are shown, and gamma ~ 109 is addressed. It is concluded that reconnection in magnetically-dominated plasma can proceed explosively, is an efficient means of particle acceleration, and is an important (perhaps dominant for some phenomena) mechanism of particle acceleration in high energy sources.

  3. Tracking parameter simulation for the Turkish accelerator center particle factory tracker system

    Energy Technology Data Exchange (ETDEWEB)

    Tapan, I., E-mail: ilhan@uludag.edu.tr; Pilicer, E.; Pilicer, F.B.

    2016-09-21

    The silicon tracker part of the Turkish Accelerator Center super charm particle factory detector was designed for effectively tracking charged particles with momentum values up to 2.0 GeV/c. In this work, the FLUKA simulation code has been used to estimate the track parameters and their resolutions in the designed tracker system. These results have been compared with those obtained by the tkLayout software package. The simulated track parameter resolutions are compatible with the physics goals of the tracking detector.

  4. Bibliography of integral charged particle nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Burrows, T.W.; Burt, J.S.

    1977-03-01

    This bibliography is divided into three main sections covering experimental, theoretical, and review references. The review section also includes compilation and evaluation references. Each section contains two subsections. The main subsection contains all references satisfying the criteria noted above and the second subsection is devoted to isotope production. The main subsections are ordered by increasing Z and A of the incident particle, then by increasing Z and A of the target nucleus. Within this order, the entries are ordered by residual nucleus and quantity (e.g., sigma(E)). Finally, the entries are ordered by outgoing particles or processes. All entries which have the same target, reaction, and quantity are grouped under a common heading with the most recent reference first. As noted above the second subsection is devoted to isotope production and is limited in the information it carries. Only those references which contain data on a definite residual nucleus or group of nuclei (e.g., fission fragments) are included in these subsections. Entries within these second subsections are ordered by increasing Z and A of the isotope produced and then by quantity. All references containing data on the same isotope production and quantity are grouped together. All lines within a group are ordered by increasing Z and A of the target and then of the incident particle. The final ordering is by increasing minimum energy.

  5. Planetary Magnetosphere Probed by Charged Dust Particles

    Science.gov (United States)

    Sternovsky, Z.; Horanyi, M.; Gruen, E.; Srama, R.; Auer, S.; Kempf, S.; Krueger, H.

    2010-12-01

    In-situ and remote sensing observations combined with theoretical and numerical modeling greatly advanced our understanding planetary magnetospheres. Dust is an integral component of the Saturnian and Jovian magnetospheres where it can act as a source/sink of plasma particles (dust particles are an effective source for plasma species like O2, OH, etc. through sputtering of ice particles, for example); its distribution is shaped by electrodynamic forces coupled radiation pressure, plasma, and neutral drag, for example. The complex interaction can lead to unusual dust dynamics, including the transport, capture, and ejection of dust grains. The study of the temporal and spatial evolution of fine dust within or outside the magnetosphere thus provides a unique way to combine data from a large number of observations: plasma, plasma wave, dust, and magnetic field measurements. The dust detectors on board the Galileo and Cassini spacecrafts lead to major discoveries, including the jovian dust stream originating from Io or the in-situ sampling and analysis of the plumes of Enceladus. Recent advancement in dust detector technology enables accurate measurement of the dust trajectory and elemental composition that can greatly enhance the understanding of dust magnetorspheric interaction and indentify the source of the dust with high precision. The capabilities of a modern dust detector thus can provide support for the upcoming Europa Jupiter System Mission.

  6. Proceeding of the 1999 Particle Accelerator Conference. Volume 2

    Science.gov (United States)

    1999-04-02

    whichh wep coulde control thes currentn source. at 4.2 K. At 77 K, the current in the coil was limited to 15 The resolution of the current drive...like APT. 970 Proceedings of the 1999 Particle Accelerator Conference, New York, 1999 APT CRYOMODULE ASSEMBLY PROCESS AND MOCKUP MODEL* B. Campbell

  7. High performance current controller for particle accelerator magnets supply

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Bidoggia, Benoit; Munk-Nielsen, Stig;

    2013-01-01

    The electromagnets in modern particle accelerators require high performance power supply whose output is required to track the current reference with a very high accuracy (down to 50 ppm). This demands very high bandwidth controller design. A converter based on buck converter topology is used in ...

  8. JMS-based SOA monitors CERN particle accelerators

    CERN Multimedia

    Seeley, Rich

    2007-01-01

    "Service-oriented architecture (SOA) may not exactly be nuclear physics, but at the CERN (European Organization for Nuclear Research) physics laboratory on the border of France and Switzerland, an SOA system is watching over giant particle accelerators." (1,5 page)

  9. Diffusiophoretic mobility of charge-regulating porous particles.

    Science.gov (United States)

    Li, Wei C; Keh, Huan J

    2016-08-01

    The diffusiophoresis of a charge-regulating porous sphere, such as polyelectrolyte coil, with an arbitrary thickness of the electric double layer in an electrolyte solution prescribed with a concentration gradient is analytically studied for the first time. The ionogenic functional groups and hydrodynamic frictional segments distribute uniformly within the permeable particle, and a charge regulation model for the association and dissociation reactions of the functional groups relates the fixed charge density to the local electric potential. The electrokinetic equations governing the electric potential, ionic electrochemical potential, and fluid velocity distributions are solved as power-series expansions in the basic fixed charge density. An explicit formula for the diffusiophoretic mobility of the particle, which vanishes at the isoelectric point, is derived from a force balance. The effects of charge regulation on the diffusiophoretic mobility, which depend on various particle and electrolyte characteristics such as the reaction equilibrium constants of the ionogenic functional groups, are significant and interesting. The variation in the bulk concentration of the charge-determining ions can produce more than one reversal in the direction of the diffusiophoretic velocity. The obtained results differ conspicuously from those of impermeable particles and provide valuable information for the interpretation of experimental data.

  10. Cryogenic Beam Screens for High-Energy Particle Accelerators

    CERN Document Server

    Baglin, V; Tavian, L; van Weelderen, R

    2013-01-01

    Applied superconductivity has become a key enabling technology for high-energy particle accelerators, thus making them large helium cryogenic systems operating at very low temperature. The circulation of high-intensity particle beams in these machines generates energy deposition in the first wall through different processes. For thermodynamic efficiency, it is advisable to intercept these beam-induced heat loads, which may be large in comparison with cryostat heat in-leaks, at higher temperature than that of the superconducting magnets of the accelerator, by means of beam screens located in the magnet apertures. Beam screens may also be used as part of the ultra-high vacuum system of the accelerator, by sheltering the gas molecules cryopumped on the beam pipe from impinging radiation and thus avoiding pressure runaway. Space being extremely tight in the magnet apertures, cooling of the long, slender beam screens also raises substantial problems in cryogenic heat transfer and fluid flow. We present sizing rule...

  11. Particle Acceleration and Nonthermal Emission in Relativistic Astrophysical Shocks

    Science.gov (United States)

    Sironi, Lorenzo

    The common observational feature of Pulsar Wind Nebulae (PWNe), gamma-ray bursts (GRBs), and AGN jets is a broad nonthermal spectrum of synchrotron and inverse Compton radiation. It is usually assumed that the emitting electrons are accelerated to a power-law distribution at relativistic shocks, via the so-called Fermi mechanism. Despite decades of research, the Fermi acceleration process is still not understood from first principles. An assessment of the micro-physics of particle acceleration in relativistic shocks is of paramount importance to unveil the properties of astrophysical nonthermal sources, and it is the subject of this dissertation. In the first part of this thesis, I explore by means of fully-kinetic first-principle particle-in-cell (PIC) simulations the properties of relativistic shocks that propagate in electron-positron and electron-proton plasmas carrying uniform magnetic fields. I find that nonthermal particle acceleration only occurs if the upstream magnetization is weak (sigma0.01) and quasi-perpendicular, yet they need to be efficient particle accelerators, in order to explain the prominent nonthermal signatures of these sources. Motivated by this discrepancy, I then relax the assumption of uniform pre-shock fields, and investigate the acceleration efficiency of perpendicular shocks that propagate in high-sigma flows with alternating magnetic fields. This is the geometry expected at the termination shock of pulsar winds, but it could also be relevant for Poynting-dominated jets in GRBs and AGNs. I show by means of PIC simulations that compression of the flow at the shock will force annihilation of nearby field lines, a process known as shock-driven reconnection. Magnetic reconnection can efficiently transfer the energy of alternating fields to the particles, generating flat power-law tails containing most of the particles. Finally, I directly relate the results of my PIC simulations to observations of nonthermal sources, by presenting a

  12. Measuring massive metastable charged particles with ATLAS RPC timing information.

    CERN Document Server

    Ellis, Jonathan Richard; Oye, Ola Kristoffer

    2006-01-01

    We investigate the measurement of massive metastable charged particles in ATLAS, using timing information from the resistive plate chambers (RPCs). As representative particle candidates we use staus, the partners of $ au$ leptons in supersymmetric models with gravitino dark matter (GDM), which may well be stable on the scale of the detector. The generic signatures of massive metastable charged particles are a long Time-of-Flight (ToF) and high energy-loss ($dE/dx$). The RPC timing information allows us to measure the ToF of a particle which, taken in conjunction with the measurement of the particle's momentum from its track, allows one to determine its mass. We pioneer the study of the RPCs' potential for this measurement. We also consider triggering effects on the event selection, and discuss quantitatively the ATLAS potential for measuring the stau mass in three specific GDM benchmark scenarios.

  13. Radiation damping forces and radiation from charged particles

    Science.gov (United States)

    Klepikov, N. P.

    1985-06-01

    In the present evaluation of reported results on the radiation reaction force to which a charged particle is subject, the expression obtained for this force by Lorentz (1909), Abraham (1904), and Dirac (1938) is noted to be in physically reasonable agreement with the radiation of energy, momentum and angular momentum; it has, moreover, been successfully used in investigations of the motion of particles in a field. A theory is presented for the losses of energy, momentum, and angular momentum by a system of charged particles as they move together, taking the external field, the radiation damping forces, and the retarded Lienard-Wiechert forces into account. Formulas are given for the spectral and angular distribution of the radiation from a system of particles, and a system of equations is constructed for finding the angular momenta of EM waves radiated by particles of the system.

  14. The United States Particle Accelerator School: Educating the next generation of accelerator scientists and engineers

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, William A.; /MIT

    2008-09-01

    Only a handful of universities in the US offer any formal training in accelerator science. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed a highly successful educational paradigm that, over the past twenty-years, has granted more university credit in accelerator / beam science and technology than any university in the world. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, crossdisciplinary research areas such as high energy density physics.

  15. Particle acceleration, magnetization and radiation in relativistic shocks

    Science.gov (United States)

    Derishev, Evgeny V.; Piran, Tsvi

    2016-08-01

    The mechanisms of particle acceleration and radiation, as well as magnetic field build-up and decay in relativistic collisionless shocks, are open questions with important implications to various phenomena in high-energy astrophysics. While the Weibel instability is possibly responsible for magnetic field build-up and diffusive shock acceleration is a model for acceleration, both have problems and current particle-in-cell simulations show that particles are accelerated only under special conditions and the magnetic field decays on a very short length-scale. We present here a novel model for the structure and the emission of highly relativistic collisionless shocks. The model takes into account (and is based on) non-local energy and momentum transport across the shock front via emission and absorption of high-energy photons. This leads to a pre-acceleration of the fluid and pre-amplification of the magnetic fields in the upstream region. Both have drastic implications on the shock structure. The model explains the persistence of the shock-generated magnetic field at large distances from the shock front. The dissipation of this magnetic field results in a continuous particle acceleration within the downstream region. A unique feature of the model is the existence of an `attractor', towards which any shock will evolve. The model is applicable to any relativistic shock, but its distinctive features show up only for sufficiently large compactness. We demonstrate that prompt and afterglow gamma-ray bursts' shocks satisfy the relevant conditions, and we compare their observations with the predictions of the model.

  16. Solar release time of solar energetic particles and associated acceleration source in corona

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Solar energetic particles (SEPs) are accelerated in corona at an early phase of solar energetic particle events (SEPE). The acceleration mechanism of SEPs in corona can only be inferred from an analysis of multi-band observational data, as the observation of SEPs is usually made around 1AU. In this context,people have investigated spectrums, charge state, solar release time (SRT), and multi-band data of SEPEs, in an attempt to judge the acceleration mechanism of SEPs. The SRT computation of SEPs is an important and commonly used approach to study the acceleration mechanism of SEPs in corona.This paper reviews some important findings concerning the SRT computation of SEPs, and analyzes different merits of each approach for such calculation, based on a range of SEPE case studies. This paper also analyzes and discusses both possible and actual acceleration mechanisms of a number of SEPEs, by calculating the SRT of the SEPEs. Finally, the paper summarizes the possible problems in studying an acceleration mechanism of SEPEs inferred from the SRT of SEP.

  17. Technical training: AXEL-2008 - Introduction to Particle Accelerators

    CERN Document Server

    2008-01-01

    CERN Technical Training 2008: Learning for the LHC! AXEL-2008 is a course series on particle accelerators, given at CERN within the framework of the AB Operation Group Shut-down Lectures. Since 2003, this course has been organized as a joint venture between the AB Department and Technical Training and is open to a wider CERN community. The AXEL-2008 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is also open to technicians, engineers and physicists interested in this field. The course does not require any prior knowledge of accelerators. However, some basic knowledge of trigonometry, matrices and differential equations and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) from 29th January to 1st February 2008, and given in English with questions and answers als...

  18. Particle acceleration near magnetic nulls using MMS data

    Science.gov (United States)

    Eriksson, Elin; Vaivads, Andris; Khotyaintsev, Yuri; Graham, Daniel; Markidis, Stefano; Peng, Ivy Bo; André, Mats; Burch, James; Lindqvist, Per-Arne; Ergun, Robert; Torbert, Roy; Magnes, Werner; Russell, Christopher; Giles, Barbara; Pollock, Craig

    2016-04-01

    Regions with vanishing magnetic field, also referred to as magnetic nulls, are of high interest in plasma physics. Near magnetic nulls particles become unmagnetized and can by interacting with electric fields be accelerated up to high energies. Magnetic nulls have been observed and studied before using using Cluster data with different methods. Magnetic nulls found by Cluster have been obtained with spacecraft separation comparable to ion scales and particle instrumentation is not sufficient to resolve in detail physical processes of particle acceleration around the null. Now we use the MMS (Magnetospheric Multiscale) data to study these processes in detail. The MMS separation is well below the ion scale and data from particle instruments has sufficient resolution during burst mode to resolve these processes for our events. We study nulls in detail during phase 1a of the MMS mission. Burst data during this phase are mainly from the magnetopause, but some intervals cover the magnetosheath, bowshock, and solar wind. We particularly focus on magnetic nulls associated with strong currents, which can potentially be associated with the electron diffusion region of magnetic reconnection. There we also expect particle acceleration to occur. A preliminary study has already identified several nulls of high interest in the burst data. We present a detailed study of these nulls.

  19. Electric birefringence anomaly of solutions of ionically charged anisometric particles.

    Science.gov (United States)

    Hoffmann, H; Gräbner, Dieter

    2015-02-01

    The term "electric birefringence anomaly" is known as the electric birefringence (EB) signal that occurs in solutions of ionically charged anisometric particles in a narrow concentration region. The signal is of opposite sign to the normal birefringence that occurs below and above this narrow concentration region. The normal electric birefringence signals in the dilute and more concentrated regions are due to the orientation of the particles in the direction of the applied electric field. The origin for the anomalous signal was not completely understood until now. The article summarises previous results in which the anomalous results had been observed but not well understood. It shows that the birefringence anomaly occurs in systems as diverse as micellar solutions, polyelectrolytes, solutions of clays, viruses and fibres. In all these systems the anomaly signals are present at the concentration when the length of the colloidal particles including the thickness of the electric double layer are about the same as the mean distance between the colloidal particles. Under these conditions the electric double layers of the particles overlap along the main axis of the particles but not in the direction across the particles. As a consequence of this situation a dipole is built up across the particles by the migration of the counter-ions of the particles in the electric field and this dipole leads to an orientation of the particles perpendicular to the electric field. The anomalous signal can usually be observed simultaneously with the normal signal. The amplitude of the anomalous signal can be larger than the amplitude of the normal signal. As a consequence the total birefringence changes its sign in the anomalous concentration region. The anomaly signal of the clays can also be explained by a fluctuating dipole around the particles, which is due to the fact that the centre of the ionic charges of the particles does not fall on the centre of the ionic charge of the counter

  20. Relativistic mixtures of charged and uncharged particles

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, Gilberto M. [Departamento de Física, Universidade Federal do Paraná, Curitiba (Brazil)

    2014-01-14

    Mixtures of relativistic gases within the framework of Boltzmann equation are analyzed. Three systems are considered. The first one refers to a mixture of uncharged particles by using Grad’s moment method, where the relativistic mixture is characterized by the moments of the distribution functions: particle four-flows, energy-momentum tensors, and third-order moment tensors. In the second Fick’s law for a mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric are derived from an extension of Marle and McCormack model equations applied to a relativistic truncated Grad’s distribution function, where it is shown the dependence of the diffusion coefficient on the gravitational potential. The third one consists in the derivation of the relativistic laws of Ohm and Fourier for a binary mixtures of electrons with protons and electrons with photons subjected to external electromagnetic fields and in presence of gravitational fields by using the Anderson and Witting model of the Boltzmann equation.

  1. On the novel mechanism of acceleration of cosmic particles

    CERN Document Server

    Osmanov, Z

    2015-01-01

    A novel model of particle acceleration in the rotating magnetospheres of active galactic nuclei (AGN) and pulsars is constructed. The particle energies may be boosted up to enormous energies in a several step mechanism. In the first stage, the Langmuir waves are centrifugally excited and amplified by means of a parametric process that efficiently pumps rotational energy to excite electrostatic fields. By considering the pulsars it is shown that the Langmuir waves very soon Landau damp on the relativistic electrons already present in a magnetosphere. It has been found that the process is so efficient that no energy losses might affect the mechanism of particle acceleration. Applying typical parameters for young pulsars we have shown that by means of this process the electrons might achieve energies of the order of $10^{18}$ eV. The situation in AGN magnetospheres is slightly different. In the second stage, the process of "Langmuir collapse" develops, creating appropriate conditions for transferring electric en...

  2. Mass, charge, and energy separation by selective acceleration with a traveling potential hill

    Science.gov (United States)

    Tung, L. Schwager; Barr, W. L.; Lowder, R. S.; Post, R. F.

    1996-10-01

    A traveling electric potential hill has been used to generate an ion beam with an energy distribution that is mass dependent from a monoenergetic ion beam of mixed masses. This effect can be utilized as a novel method for mass separation applied to identification or enrichment of ions (e.g., of elements, isotopes, or molecules). This theory for mass-selective acceleration is presented here and is shown to be confirmed by experiment and by a time-dependent particle-in-cell computer simulation. Results show that monoenergetic ions with the particular mass of choice are accelerated by controlling the hill potential and the hill velocity. The hill velocity is typically 20%-30% faster than the ions to be accelerated. The ability of the hill to pickup a particular mass uses the fact that small kinetic energy differences in the lab frame appear much larger in the moving hill frame. Ions will gain energy from the approaching hill if their relative energy in the moving hill frame is less than the peak potential of the hill. The final energy of these accelerated ions can be several times the source energy, which facilitates energy filtering for mass purification or identification. If the hill potential is chosen to accelerate multiple masses, the heaviest mass will have the greatest final energy. Hence, choosing the appropriate hill potential and collector retarding voltage will isolate ions with the lightest, heaviest, or intermediate mass. In the experimental device, called a Solitron, purified 20Ne and 22Ne are extracted from a ribbon beam of neon that is originally composed of 20Ne:22Ne in the natural ratio of 91:9. The isotopic content of the processed beam is determined by measuring the energy distribution of the detected current. These results agree with the theory. In addition to mass selectivity, our theory can also be applied to the filtration of an ion beam according to charge state or energy. Because of this variety of properties, the Solitron is envisioned to

  3. The use of heavy charged particles in the radiation therapy of tumors

    CERN Document Server

    Kraft, G

    1995-01-01

    Beams of heavy charged particles like carbon or oxygen ions represent the ultimate tool of external radiotherapy of deep-seated tumors.Small range and lateral scattering and the increase of the energy deposition with penetration depth are the physical basis for a more efficient tumor targeting. High biological efficiency in the tumor is the perequisite for a successful treatment of tumors radioresistant to sparsely ionizing radiation.The possibility to perform target-conform irradiation and to control the achieved actual distribution using PET techniques guarantees that biological highly efficient stopping particles can be restricted to the tumor volume only.Although the physical and radiobiological properties of ion beams are very favorable for therapy, the necessity to produce these particles in an accelerator has restricted the general application of heavy ions up to now.Presently, the heavy ion accelerator SIS at GSI is the only source of heavy ion beams sufficient in enrgy and intensity for therapy in Eu...

  4. Electromagnetic radiation of charged particles in stochastic motion

    CERN Document Server

    Harko, Tiberiu

    2016-01-01

    The study of the Brownian motion of a charged particle in electric and magnetic fields fields has many important applications in plasma and heavy ions physics, as well as in astrophysics. In the present paper we consider the electromagnetic radiation properties of a charged non-relativistic particle in the presence of electric and magnetic fields, of an exterior non-electromagnetic potential, and of a friction and stochastic force, respectively. We describe the motion of the charged particle by a Langevin and generalized Langevin type stochastic differential equation. We investigate in detail the cases of the Brownian motion with or without memory in a constant electric field, in the presence of an external harmonic potential, and of a constant magnetic field. In all cases the corresponding Langevin equations are solved numerically, and a full description of the spectrum of the emitted radiation and of the physical properties of the motion is obtained. The Power Spectral Density (PSD) of the emitted power is ...

  5. Preparation of Panel and Charged Particles for Electrophoretic Display

    Science.gov (United States)

    Choi, Hyung Suk; Park, Jin Woo; Park, Lee Soon; Lee, Jung Kyung; Han, Yoon Soo; Kwon, Younghwan

    Studies on the formulation of photosensitive paste for transparent soft mold press (TSMP) method have been performed. With the optimum formulation of the photosensitive paste the box-type barrier rib with good flexibility and high solvent resistance was fabricated, suitable for the panel material of the electrophoretic display. Cationically-charged white particles were prepared by using TiO2 nanoparticles, silane coupling agent with amino groups, dispersant and acetic acid. The cationically charged TiO2 particles exhibited 74.09 mV of zeta potential and 3.11 × 10-5 cm2/Vs of mobility. Electrophoretic display fabricated with the charged TiO2 particles exhibited 10 V of low driving voltage and maximum contrast ratio (5.3/1) at 30 V.

  6. Medical radiation dosimetry theory of charged particle collision energy loss

    CERN Document Server

    McParland, Brian J

    2014-01-01

    Accurate radiation dosimetry is a requirement of radiation oncology, diagnostic radiology and nuclear medicine. It is necessary so as to satisfy the needs of patient safety, therapeutic and diagnostic optimisation, and retrospective epidemiological studies of the biological effects resulting from low absorbed doses of ionising radiation. The radiation absorbed dose received by the patient is the ultimate consequence of the transfer of kinetic energy through collisions between energetic charged particles and atoms of the tissue being traversed. Thus, the ability of the medical physicist to both measure and calculate accurately patient dosimetry demands a deep understanding of the physics of charged particle interactions with matter. Interestingly, the physics of charged particle energy loss has an almost exclusively theoretical basis, thus necessitating an advanced theoretical understanding of the subject in order to apply it appropriately to the clinical regime. ​ Each year, about one-third of the worl...

  7. Design of asymmetric particles containing a charged interior and a neutral surface charge: comparative study on in vivo circulation of polyelectrolyte microgels.

    Science.gov (United States)

    Chen, Kai; Xu, Jing; Luft, J Christopher; Tian, Shaomin; Raval, Jay S; DeSimone, Joseph M

    2014-07-16

    Lowering the modulus of hydrogel particles could enable them to bypass in vivo physical barriers that would otherwise filter particles with similar size but higher modulus. Incorporation of electrolyte moieties into the polymer network of hydrogel particles to increase the swelling ratio is a straightforward and quite efficient way to decrease the modulus. In addition, charged groups in hydrogel particles can also help secure cargoes. However, the distribution of charged groups on the surface of a particle can accelerate the clearance of particles. Herein, we developed a method to synthesize highly swollen microgels of precise size with near-neutral surface charge while retaining interior charged groups. A strategy was employed to enable a particle to be highly cross-linked with very small mesh size, and subsequently PEGylated to quench the exterior amines only without affecting the internal amines. Acidic degradation of the cross-linker allows for swelling of the particles to microgels with a desired size and deformability. The microgels fabricated demonstrated extended circulation in vivo compared to their counterparts with a charged surface, and could potentially be utilized in in vivo applications including as oxygen carriers or nucleic acid scavengers.

  8. Magnetic moment conservation and particles acceleration in turbulence

    Science.gov (United States)

    Dalena, S.; Greco, A.; Matthaeus, W. H.

    2010-12-01

    The present work concerns the study of particle magnetic moment conservation in the presence of turbulent magnetic fields. As we know from the particle orbit theory, for slow temporal and spatial magnetic field variations(i.e. if their characteristic length and time are greater than the particle orbit diameter and the time spent by a particle to execute one orbit, respectively), the magnetic moment, defined as μ = (v^2⊥ /B) (averaged over the particle gyroperiod) is an adiabatic invariant and remains constant during particle motion. But in presence of a well developed magnetic turbulence μ can undergo rapid variations and might not be constant anymore. Of course, this fact could influence particle acceleration and could have a considerable implications in many astrophysical problems, such as coronal heating. In order to reproduce and extend some of the results obtained by Karimabadi et al. 1992, we study the interaction between ions and a single or a couple of electromagnetic waves. We varied both the wave frequency and the cosine of pitch angle at which particles are injected, in order to observe in this very simple case which is the limit for magnetic moment conservation. We also will reconsider the results of Dmitruk and Matthaeus (2006) regarding particle acceleration in turbulence, taking into account statistics of the magnetic moment (see also Lehe et al., 2010). Later we will add more waves to obtain a complete turbulent spectrum. The final aim of this research work is the understanding the behavior of particles magnetic moment during magnetic reconnection phenomena. H. Karimabadi, D. Krauss-Varban and T. Teresawa, JGR, 97, 13853, 1992. P. Dmitruk and W. H. Matthaeus, JGR, 11, A12110, 2006. R. Lehe, I. J. Parrish and E. Quataert, Astrophys. J. 707, 404, 2009.

  9. Particle acceleration, magnetization and radiation in relativistic shocks

    CERN Document Server

    Derishev, Evgeny V

    2015-01-01

    What are the mechanisms of particle acceleration and radiation, as well as magnetic field build up and decay in relativistic shocks are open questions with important implications to various phenomena in high energy astrophysics. While the Weibel instability is possibly responsible for magnetic field build up and diffusive shock acceleration is a model for acceleration, both have problems and current PIC simulation show that particles are accelerated only under special conditions and the magnetic field decays on a short length scale. We present here a novel model for the structure and the emission of highly relativistic collisionless shocks. The model takes into account (and is based on) non-local energy and momentum transport across the shock front via emission and absorption of high-energy photons. This leads to a pre-acceleration of the fluid and pre-amplificaiton of the magnetic fields in the upstream region. Both have drastic implications on the shock structure. The model explains the persistence of the s...

  10. Test particle acceleration in torsional spine magnetic reconnection

    Science.gov (United States)

    Hosseinpour, M.

    2014-10-01

    Three-dimensional (3D) magnetic reconnection is taking place commonly in astrophysical and space plasmas, especially in solar flares which are rich sources of highly energetic particles. One of the proposed mechanisms for steady-state 3D magnetic reconnection is "torsional spine reconnection". By using the magnetic and electric fields for "torsional spine reconnection", we numerically investigate the features of test particle acceleration with input parameters for the solar corona. We show that efficient acceleration of a relativistic proton is possible near the null point where it can gain up to 100 MeV of kinetic energy within a few milliseconds. However, varying the injection position results in different scenarios for proton acceleration. A proton is most efficiently accelerated when it is injected at the point where the magnetic field lines change their curvature in the fan plane. Moreover, a proton injected far away from the null point cannot be accelerated and, even in some cases, it is trapped in the magnetic field. In addition, adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory.

  11. A New Mechanism of Higgs Bosons in Producing Charge Particles

    DEFF Research Database (Denmark)

    Javadi, Hossein; Forouzbakhsh, Farshid

    2006-01-01

    A new production method of elementary particles by Higgs Bosons will be shown. But before that the structure of photon will be considered deeply, while a new definition of Higgs Boson about color-charges and color-magnet will be given for the first time.......A new production method of elementary particles by Higgs Bosons will be shown. But before that the structure of photon will be considered deeply, while a new definition of Higgs Boson about color-charges and color-magnet will be given for the first time....

  12. Final Report - Interaction of radiation and charged particles in miniature plasma structures

    Energy Technology Data Exchange (ETDEWEB)

    Antonsen, Thomas M. [Univ. of Maryland, College Park, MD (United States). Inst. for Electronics and Applied Physics

    2014-07-16

    The extension of our program to the development of theories and models capable of describing the interactions of intense laser pulses and charged particles in miniature plasma channels is reported. These channels, which have recently been created in the laboratory, have unique dispersion properties that make them interesting for a variety of applications including particle acceleration, high harmonic generation, and THz generation. Our program systematically explored the properties of these channels, including dispersion, losses, and coupling. A particular application that was pursued is the generation of intense pulses of THz radiation by short laser pulses propagating these channels. We also explored the nonlinear dynamics of laser pulses propagating in these channels.

  13. Optical stochastic cooling method in application to the beams of charged particles

    CERN Document Server

    Gessonov, E G

    2014-01-01

    We discuss the optical stochastic cooling (OSC) method in applications to the beams of charged particles, circulating in accelerators and storage rings. In this publication we concentrated on various OSC schemes in a diluted beam approximation, when the heating of selected particle by its neighboring ones could be neglected. Even so, this approximation allows us to identify important features in the beam cooling. In the forthcoming publication, on the basis of approach developed here, we will include effects of heating in the dynamics of cooling.

  14. Particle acceleration, transport and turbulence in cosmic and heliospheric physics

    Science.gov (United States)

    Matthaeus, W.

    1992-01-01

    In this progress report, the long term goals, recent scientific progress, and organizational activities are described. The scientific focus of this annual report is in three areas: first, the physics of particle acceleration and transport, including heliospheric modulation and transport, shock acceleration and galactic propagation and reacceleration of cosmic rays; second, the development of theories of the interaction of turbulence and large scale plasma and magnetic field structures, as in winds and shocks; third, the elucidation of the nature of magnetohydrodynamic turbulence processes and the role such turbulence processes might play in heliospheric, galactic, cosmic ray physics, and other space physics applications.

  15. THE MAXIMUM ENERGY OF ACCELERATED PARTICLES IN RELATIVISTIC COLLISIONLESS SHOCKS

    Energy Technology Data Exchange (ETDEWEB)

    Sironi, Lorenzo [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Spitkovsky, Anatoly [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States); Arons, Jonathan, E-mail: lsironi@cfa.harvard.edu [Department of Astronomy, Department of Physics, and Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States)

    2013-07-01

    The afterglow emission from gamma-ray bursts (GRBs) is usually interpreted as synchrotron radiation from electrons accelerated at the GRB external shock that propagates with relativistic velocities into the magnetized interstellar medium. By means of multi-dimensional particle-in-cell simulations, we investigate the acceleration performance of weakly magnetized relativistic shocks, in the magnetization range 0 {approx}< {sigma} {approx}< 10{sup -1}. The pre-shock magnetic field is orthogonal to the flow, as generically expected for relativistic shocks. We find that relativistic perpendicular shocks propagating in electron-positron plasmas are efficient particle accelerators if the magnetization is {sigma} {approx}< 10{sup -3}. For electron-ion plasmas, the transition to efficient acceleration occurs for {sigma} {approx}< 3 Multiplication-Sign 10{sup -5}. Here, the acceleration process proceeds similarly for the two species, since the electrons enter the shock nearly in equipartition with the ions, as a result of strong pre-heating in the self-generated upstream turbulence. In both electron-positron and electron-ion shocks, we find that the maximum energy of the accelerated particles scales in time as {epsilon}{sub max}{proportional_to}t {sup 1/2}. This scaling is shallower than the so-called (and commonly assumed) Bohm limit {epsilon}{sub max}{proportional_to}t, and it naturally results from the small-scale nature of the Weibel turbulence generated in the shock layer. In magnetized plasmas, the energy of the accelerated particles increases until it reaches a saturation value {epsilon}{sub sat}/{gamma}{sub 0} m{sub i}c {sup 2} {approx} {sigma}{sup -1/4}, where {gamma}{sub 0} m{sub i}c {sup 2} is the mean energy per particle in the upstream bulk flow. Further energization is prevented by the fact that the self-generated turbulence is confined within a finite region of thickness {proportional_to}{sigma}{sup -1/2} around the shock. Our results can provide physically

  16. Thermodiffusion of charged colloids: single-particle diffusion.

    Science.gov (United States)

    Dhont, Jan K G; Wiegand, S; Duhr, S; Braun, D

    2007-02-13

    An expression for the single-particle thermal diffusion coefficient of a charged colloidal sphere is derived on the basis of force balance on the Brownian time scale in combination with thermodynamics. It is shown that the single-particle thermal diffusion coefficient is related to the temperature dependence of the reversible work necessary to build the colloidal particle, including the core, the solvation layer, and the electrical double layer. From this general expression, an explicit expression for the contribution of the electrical double layer to the single-particle thermal diffusion coefficient is derived in terms of the surface charge density of the colloidal sphere, the electrostatic screening length, and its core radius, to within the Debye-Hückel approximation. This result is shown to explain experimental data, for both thin and thick double layers. In addition, a comparison with other theories is made.

  17. Surface modification for polystyrene colloidal particles with controlled charge densities.

    Science.gov (United States)

    Lee, Jongman; Kwon, Oh-Sun; Shin, Kwanwoo; Song, Ju-Myung; Kim, Joon-Seop; Seo, Young-Soo; Tael, Giyoong; Jon, Sangyong

    2007-11-01

    A significant amount of polystyrene sulfonated acid (PSSA) and poly(styrene-ran-acrylic acid) (PSAA) random copolymer can be adsorbed by dispersion of PS particles via a swelling-quenching process. A THF-water mixed solvent was used in the swelling process and a large amount of pure water was used, to give a low concentration of THF% in quenching process. Our results showed that functional PSSA groups were randomly and tightly adsorbed to the PS particles. When the mol.% of charged segments was increased, the progressive adsorption of PSSA chains to the PS particles leads to an increase in the electrophoretic mobility and zeta-potential of aqueous dispersions. Thus, we were able to obtain well-distributed surface charge density on the PS particles.

  18. Support Vector Machine Based on Adaptive Acceleration Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Mohammed Hasan Abdulameer

    2014-01-01

    Full Text Available Existing face recognition methods utilize particle swarm optimizer (PSO and opposition based particle swarm optimizer (OPSO to optimize the parameters of SVM. However, the utilization of random values in the velocity calculation decreases the performance of these techniques; that is, during the velocity computation, we normally use random values for the acceleration coefficients and this creates randomness in the solution. To address this problem, an adaptive acceleration particle swarm optimization (AAPSO technique is proposed. To evaluate our proposed method, we employ both face and iris recognition based on AAPSO with SVM (AAPSO-SVM. In the face and iris recognition systems, performance is evaluated using two human face databases, YALE and CASIA, and the UBiris dataset. In this method, we initially perform feature extraction and then recognition on the extracted features. In the recognition process, the extracted features are used for SVM training and testing. During the training and testing, the SVM parameters are optimized with the AAPSO technique, and in AAPSO, the acceleration coefficients are computed using the particle fitness values. The parameters in SVM, which are optimized by AAPSO, perform efficiently for both face and iris recognition. A comparative analysis between our proposed AAPSO-SVM and the PSO-SVM technique is presented.

  19. Particle Acceleration in Relativistic Magnetized Collisionless Electron-Ion Shocks

    CERN Document Server

    Sironi, Lorenzo

    2010-01-01

    We investigate shock structure and particle acceleration in relativistic magnetized collisionless electron-ion shocks by means of 2.5D particle-in-cell simulations with ion-to-electron mass ratios (m_i/m_e) ranging from 16 to 1000. We explore a range of inclination angles between the pre-shock magnetic field and the shock normal. In "subluminal" shocks, where relativistic particles can escape ahead of the shock along the magnetic field lines, ions are efficiently accelerated via a Fermi-like mechanism. The downstream ion spectrum consists of a relativistic Maxwellian and a high-energy power-law tail, which contains ~5% of ions and ~30% of ion energy. Its slope is -2.1. Upstream electrons enter the shock with lower energy than ions, so they are more strongly tied to the field. As a result, only ~1% of the incoming electrons are Fermi-accelerated at the shock before being advected downstream, where they populate a steep power-law tail (with slope -3.5). For "superluminal" shocks, where relativistic particles ca...

  20. Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data

    Energy Technology Data Exchange (ETDEWEB)

    Rubel, Oliver; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Wu, Kesheng; Prabhat,; Weber, Gunther H.; Ushizima, Daniela M.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

    2009-10-19

    Numerical simulations of laser wakefield particle accelerators play a key role in the understanding of the complex acceleration process and in the design of expensive experimental facilities. As the size and complexity of simulation output grows, an increasingly acute challenge is the practical need for computational techniques that aid in scientific knowledge discovery. To that end, we present a set of data-understanding algorithms that work in concert in a pipeline fashion to automatically locate and analyze high energy particle bunches undergoing acceleration in very large simulation datasets. These techniques work cooperatively by first identifying features of interest in individual timesteps, then integrating features across timesteps, and based on the information derived perform analysis of temporally dynamic features. This combination of techniques supports accurate detection of particle beams enabling a deeper level of scientific understanding of physical phenomena than hasbeen possible before. By combining efficient data analysis algorithms and state-of-the-art data management we enable high-performance analysis of extremely large particle datasets in 3D. We demonstrate the usefulness of our methods for a variety of 2D and 3D datasets and discuss the performance of our analysis pipeline.

  1. Generation of narrow peaks in spectroscopy of charged particles

    Science.gov (United States)

    Dubbers, Dirk; Schmidt, Ulrich

    2016-11-01

    In spectroscopy of charged particles, narrow peaks may appear in continuous spectra if magnetic transport of the particles is involved. These artefacts, which so far have escaped the attention of investigators, can develop whenever geometric detection efficiency is less than 100%. As such peaks may be misinterpreted as new physics, their generation is investigated, both analytically and experimentally, for various detector configurations, including those used in searches for the spontaneous decay of the vacuum in heavy-ion collisions.

  2. Particle Acceleration at a Flare Termination Shock: Effect of Large-scale Magnetic Turbulence

    CERN Document Server

    Guo, Fan

    2012-01-01

    We investigate the acceleration of charged particles (both electrons and protons) at collisionless shocks predicted to exist in the vicinity of solar flares. The existence of standing termination shocks has been examined by flare models and numerical simulations e.g., Shibata,Forbes. We study electron energization by numerically integrating the equations of motion of a large number of test-particle electrons in the time-dependent two-dimensional electric and magnetic fields generated from hybrid simulations (kinetic ions and fluid electron) using parameters typical of the solar flare plasma environment. The shock is produced by injecting plasma flow toward a rigid piston. Large-scale magnetic fluctuations -- known to exist in plasmas and known to have important effects on the nonthermal electron acceleration at shocks -- are also included in our simulations. For the parameters characteristic of the flaring region, our calculations suggest that the termination shock formed in the reconnection outflow region (a...

  3. Extreme Particle Acceleration via Magnetic Reconnection in the Crab Nebula

    Science.gov (United States)

    Cerutti, Benoit; Uzdensky, D. A.; Begelman, M. C.

    2012-01-01

    The discovery by Agile and Fermi of intense day-long synchrotron gamma-ray flares above 100 MeV in the Crab Nebula challenges classical models of pulsar wind nebulae and particle acceleration. We argue that the flares are powered by magnetic reconnection in the nebula. Using relativistic test-particle simulations, we show that particles are naturally focused into a thin fan beam, deep inside the reconnection layer where the magnetic field is small. The particles then suffer less from synchrotron losses and pile up at the maximum energy given by the electric potential drop in the layer. Applying this model to the Crab Nebula, we find that the emerging synchrotron emission spectrum above 100 MeV is consistent with the September 2010 flare observations. No detectable emission is expected at other wavelengths. This scenario provides a viable explanation for the Crab Nebula gamma-ray flares.

  4. Particle-In-Cell Simulation of Electron Acceleration in Solar Coronal Jets

    CERN Document Server

    Baumann, G

    2012-01-01

    We investigate electron acceleration resulting from 3D magnetic reconnection between an emerging, twisted magnetic flux rope and a pre-existing weak, open magnetic field. We first follow the rise of an unstable, twisted flux tube with a resistive MHD simulation where the numerical resolution is enhanced by using fixed mesh refinement. As in previous MHD investigations of similar situations the rise of the flux tube into the pre-existing inclined coronal magnetic field results in the formation of a solar coronal jet. A snapshot of the MHD model is then used as an initial and boundary condition for a particle-in-cell simulation, using up to half a billion cells and over 20 billion charged particle. Particle acceleration occurs mainly in the reconnection current sheet, with accelerated electrons displaying a power law dN/dE distribution with an index of about -1.65. The main acceleration mechanism is a systematic electric field, striving to maintaining the electric current in the current sheet against losses cau...

  5. Particle-in-cell Simulation of Electron Acceleration in Solar Coronal Jets

    Science.gov (United States)

    Baumann, G.; Nordlund, Å.

    2012-11-01

    We investigate electron acceleration resulting from three-dimensional magnetic reconnection between an emerging, twisted magnetic flux rope and a pre-existing weak, open magnetic field. We first follow the rise of an unstable, twisted flux tube with a resistive MHD simulation where the numerical resolution is enhanced by using fixed mesh refinement. As in previous MHD investigations of similar situations, the rise of the flux tube into the pre-existing inclined coronal magnetic field results in the formation of a solar coronal jet. A snapshot of the MHD model is then used as an initial and boundary condition for a particle-in-cell simulation, using up to half a billion cells and over 20 billion charged particles. Particle acceleration occurs mainly in the reconnection current sheet, with accelerated electrons displaying a power law in the energy probability distribution with an index of around -1.5. The main acceleration mechanism is a systematic electric field, striving to maintaining the electric current in the current sheet against losses caused by electrons not being able to stay in the current sheet for more than a few seconds at a time.

  6. Proceeding of the 1999 Particle Accelerator Conference. Volume 3

    Science.gov (United States)

    2007-11-02

    1995 Particle Accel. Conf. (1995) 2312 78 [6] R. J. Hayden and M. J. Jakobson , "The Space Charge Computer 0 Program SCHAR", IEEE Transactions on...324S0 9 [7] R. J. Hayden and M. J. Jakobson , "The Space-Charge ComputerGib ý"! t 4Program SCHAR,’" IEETrans. Nucl. Sci. NS-30 (1983) 2540-2. 1ý .0... Roman G. 78, 750 Fukuda, Mitsuhiro 2259 Gilpatrick, John D. 2152,2214, 2241, 3528, 3582 Gross, Dan 2936 Fukuda, Shigeki 3414 Ginzburg, Naum S. 1055

  7. Hamiltonian and Lagrangian dynamics of charged particles including the effects of radiation damping

    Science.gov (United States)

    Qin, Hong; Burby, Joshua; Davidson, Ronald; Fisch, Nathaniel; Chung, Moses

    2015-11-01

    The effects of radiation damping (radiation reaction) on accelerating charged particles in modern high-intensity accelerators and high-intensity laser beams have becoming increasingly important. Especially for electron accelerators and storage rings, radiation damping is an effective mechanism and technique to achieve high beam luminosity. We develop Hamiltonian and Lagrangian descriptions of the classical dynamics of a charged particle including the effects of radiation damping in the general electromagnetic focusing channels encountered in accelerators. The direct connection between the classical Hamiltonian and Lagrangian theories and the more fundamental QED description of the synchrotron radiation process is also addressed. In addition to their theoretical importance, the classical Hamiltonian and Lagrangian theories of the radiation damping also enable us to numerically integrate the dynamics using advanced structure-preserving geometric algorithms. These theoretical developments can also be applied to runaway electrons and positrons generated during the disruption or startup of tokamak discharges. This research was supported by the U.S. Department of Energy (DE-AC02-09CH11466).

  8. Reliability Approach for Machine Protection Design in Particle Accelerators

    CERN Document Server

    Apollonio, A; Mikulec, B; Puccio, B; Sanchez Alvarez, J L; Schmidt, R; Wagner, S

    2013-01-01

    Particle accelerators require Machine Protection Systems (MPS) to prevent beam-induced damage of equipment in case of failures. This becomes increasingly important for proton colliders with large energy stored in the beam such as LHC, for high power accelerators with a beam power of up to 10 MW, such as the European Spallation Source (ESS), and for linear colliders with high beam power and very small beam size. The reliability of Machine Protection Systems is crucial for safe machine operation; all possible sources of risk need to be taken into account in the early design stage. This paper presents a systematic approach to classify failures and to assess the associated risk, and discusses the impact of such considerations on the design of Machine Protection Systems. The application of this approach will be illustrated using the new design of the MPS for LINAC4, a linear accelerator under construction at CERN.

  9. Stochastic Particle Acceleration in Turbulence Generated by the Magnetorotational Instability

    CERN Document Server

    Kimura, Shigeo S; Suzuki, Takeru K; Inutsuka, Shu-ichiro

    2016-01-01

    We investigate stochastic particle acceleration in accretion flows. It is believed that the magnetorotational instability (MRI) generates turbulence inside accretion flows and that cosmic rays (CRs) are accelerated by the turbulence. We calculate equations of motion for CRs in the turbulent fields generated by MRI with the shearing box approximation without back reaction to the field. The results show that the CRs randomly gain or lose their energies through the interaction with the turbulent fields. The CRs diffuse in the configuration space anisotropically: The diffusion coefficient in direction of the unperturbed flow is about twenty times higher than the Bohm coefficient, while those in the other directions are only a few times higher than the Bohm. The momentum distribution is isotropic, and its evolution can be described by the diffusion equation in momentum space where the diffusion coefficient is a power-law function of the CR momentum. We show that the shear acceleration efficiently works for energet...

  10. Charged Particle Energization and Transport in the Magnetotail during Substorms

    Science.gov (United States)

    Pan, Qingjiang

    This dissertation addresses the problem of energization of particles (both electrons and ions) to tens and hundreds of keV and the associated transport process in the magnetotail during substorms. Particles energized in the magnetotail are further accelerated to even higher energies (hundreds of keV to MeV) in the radiation belts, causing space weather hazards to human activities in space and on ground. We develop an analytical model to quantitatively estimate flux changes caused by betatron and Fermi acceleration when particles are transported along narrow high-speed flow channels from the magnetotail to the inner magnetosphere. The model shows that energetic particle flux can be significantly enhanced by a modest compression of the magnetic field and/or shrinking of the distance between the magnetic mirror points. We use coordinated spacecraft measurements, global magnetohydrodynamic (MHD) simulations driven by measured upstream solar wind conditions, and large-scale kinetic (LSK) simulations to quantify electron local acceleration in the near-Earth reconnection region and nonlocal acceleration during plasma earthward transport. Compared to the analytical model, application of the LSK simulations is much less restrictive because trajectories of millions of test particles are calculated in the realistically determined global MHD fields and the results are statistical. The simulation results validated by the observations show that electrons following a power law distribution at high energies are generated earthward of the reconnection site, and that the majority of the energetic electrons observed in the inner magnetosphere are caused by adiabatic acceleration in association with magnetic dipolarizations and fast flows during earthward transport. We extend the global MHD+LSK simulations to examine ion energization and compare it with electron energization. The simulations demonstrate that ions in the magnetotail are first nonadiabatically accelerated in the weak

  11. Radial equilibrium of relativistic particle bunches in plasma wakefield accelerators

    CERN Document Server

    Lotov, K V

    2016-01-01

    Drive particle beams in linear or weakly nonlinear regimes of the plasma wakefield accelerator quickly reach a radial equilibrium with the wakefield, which is described in detail for the first time. The equilibrium beam state and self-consistent wakefields are obtained by combining analytical relationships, numerical integration, and first-principle simulations. In the equilibrium state, the beam density is strongly peaked near the axis, the beam radius is constant along the beam, and longitudinal variation of the focusing strength is balanced by varying beam emittance. The transverse momentum distribution of beam particles depends on the observation radius and is neither separable, nor Gaussian.

  12. Connecting inflation with late cosmic acceleration by particle production

    CERN Document Server

    Nunes, Rafael C

    2016-01-01

    A continuous process of creation of particles is investigated as a possible connection between the inflationary stage with late cosmic acceleration. In this model, the inflationary era occurs due to a continuous and fast process of creation of relativistic particles, and the recent accelerating phase is driven by the non-relativistic matter creation from the gravitational field acting on the quantum vacuum, which finally results in an effective equation of state less than $-1$. Thus, explaining recent results in favor of a phantom dynamics without the need of any modifications in the gravity theory has been proposed. Finally, we confront the model with recent observational data of type Ia Supernova, history of the Hubble parameter, baryon acoustic oscillations, and the cosmic microwave background.

  13. Single particles accelerate final stages of capillary break up

    CERN Document Server

    Lindner, Anke; Wagner, Christian

    2015-01-01

    Droplet formation of suspensions is present in many industrial and technological processes such as coating and food engineering. Whilst the finite time singularity of the minimum neck diameter in capillary break-up of simple liquids can be described by well known self-similarity solutions, the pinching of non-Brownian suspension depends in a complex way on the particle dynamics in the thinning thread. Here we focus on the very dilute regime where the filament contains only isolated beads to identify the physical mechanisms leading to the pronounced acceleration of the filament thinning observed. This accelerated regime is characterized by an asymmetric shape of the filament with an enhanced curvature that depends on the size and the spatial distribution of the particles within the capillary thread.

  14. The appreciation of stochastic motion in particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Symon, Keith; Sessler, Andrew

    2003-08-03

    A description is given of the analytic and numerical work, performed from July 1955 through August 1956, so as to develop, and then study, the process of making intense proton beams, suitable for colliding beams. It is shown how this investigation led, in a most natural way, to the realization that stochasticity can arise in a simple Hamiltonian system. Furthermore, the criterion for the onset of stochasticity was understood, and carefully studied, in two different situations. The first situation was the proposed (and subsequently used) ''stacking process'' for developing an intense beam, where stochasticity occurs as additional particles are added to the intense circulating beam. The second situation occurs when one seeks to develop ''stochastic accelerators'' in which particles are accelerated (continuously) by a collection of radio frequency systems. It was in the last connection that the well-known criterion for stochasticity, resonance overlap, was obtained.

  15. Observational Evidence of Particle Acceleration Associated with Plasmoid Motions

    CERN Document Server

    Takasao, Shinsuke; Isobe, Hiroaki; Shibata, Kazunari

    2016-01-01

    We report a strong association between the particle acceleration and plasma motions found in the 2010 August 18 solar flare. The plasma motions are tracked in the extreme-ultraviolet (EUV) images taken by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory and the Extreme UltraViolet Imager (EUVI) on the Solar Terrestrial Relation Observatory spacecraft Ahead, and the signature of particle acceleration was investigated by using Nobeyama Radioheliograph data. In our previous paper, we reported that in EUV images many plasma blobs appeared in the current sheet above the flare arcade. They were ejected bidirectionally along the current sheet, and the blobs that were ejected sunward collided with the flare arcade. Some of them collided or merged with each other before they were ejected from the current sheet. We discovered impulsive radio bursts associated with such plasma motions (ejection, coalescence, and collision with the post flare loops). The radio bursts are considered to be the...

  16. Equations of motion for charged particles in strong laser fields

    CERN Document Server

    Ruhl, Hartmut

    2016-01-01

    Starting from the Dirac equation coupled to a classical radiation field a set of equations of motion for charged quasi-particles in the classical limit for slowly varying radiation and matter fields is derived. The radiation reaction term derived in the paper is the Abraham-Lorentz-Dirac term.

  17. Functionally charged nanosize particles differentially activate BV2 microglia.

    Science.gov (United States)

    The effect of particle surface charge on the biological activation of immortalized mouse microglia (BV2) was examined. Nanosize (860-950 nm) spherical polystyrene microparticles (SPM) were coated with carboxyl (COOH-) or dimethyl amino (CH3)2-N- groups to give a net negative or p...

  18. Measurements of charged-particle distributions with the ATLAS detector

    CERN Document Server

    Cairo, Valentina Maria Martina

    2016-01-01

    Inclusive charged-particle measurements probe the low-energy region of the non-perturbative quantum chromodynamics. The ATLAS collaboration has recently measured the charged-particle multiplicity and its dependence on transverse momentum and pseudorapidity in special data sets with low LHC beam currents, recorded at centre-of-mass energies of 8 TeV and 13 TeV. The measurements at 8 TeV cover a wide spectrum using charged-particle selections with minimum transverse momentum of both 100 MeV and 500 MeV and in various phase space regions of low and high charged-particle multiplicities, some of which are studied for the first time by ATLAS. The measurements at 13 TeV also present detailed studies with a minimum transverse momentum of both 100 MeV and 500 MeV. The measurements are compared with predictions of various tuned Monte Carlo generators and are found to provide strong constraints on these. None of the Monte Carlo generators with their respective tunes are able to reproduce all the features of the data.

  19. Thermodynamic model for bouncing charged particles inside a capacitor

    Science.gov (United States)

    Rezaeizadeh, Amin; Mameghani, Pooya

    2013-08-01

    We introduce an equation of state for a conducting particle inside a charged parallel-plate capacitor and show that it is similar to the equation of state for an ideal gas undergoing an adiabatic process. We describe a simple experiment that shows reasonable agreement with the theoretical model.

  20. The Mathematics of Charged Particles interacting with Electromagnetic Fields

    DEFF Research Database (Denmark)

    Petersen, Kim

    In this thesis, we study the mathematics used to describe systems of charged quantum mechanical particles coupled with their classical self-generated electromagnetic field. We prove the existence of a unique local in time solution to the many-body Maxwell-Schrödinger initial value problem expressed...

  1. Kerr black holes as particle accelerators to arbitrarily high energy.

    Science.gov (United States)

    Bañados, Máximo; Silk, Joseph; West, Stephen M

    2009-09-11

    We show that intermediate mass black holes conjectured to be the early precursors of supermassive black holes and surrounded by relic cold dark matter density spikes can act as particle accelerators with collisions, in principle, at arbitrarily high center-of-mass energies in the case of Kerr black holes. While the ejecta from such interactions will be highly redshifted, we may anticipate the possibility of a unique probe of Planck-scale physics.

  2. Search for new charged massive stable particles at CDF

    Science.gov (United States)

    CDF Collaboration

    1996-05-01

    We report on a general search at CDF for new particles which are electrically charged and sufficiently long-lived to allow detection (γ c τ >= 1m). Examples of such particles include free quarks, 4th generation leptons which are lighter than their neutrino, and sextet quarks. Their signature would be particles with high momentum but relatively low velocity, β Fisica Nucleare; the Ministry of Education, Science and Culture of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; and the A. P. Sloan Foundation. Supported by U.S. DOE under Contract No. DE-AC02-76CH03000.

  3. Charge fluctuations for particles on a surface exposed to plasma

    CERN Document Server

    Sheridan, T E

    2011-01-01

    We develop a stochastic model for the charge fluctuations on a microscopic dust particle resting on a surface exposed to plasma. We find in steady state that the fluctuations are normally distributed with a standard deviation that is proportional to $CT_{e})^{1/2}$, where $C$ is the particle-surface capacitance and $T_{e}$ is the plasma electron temperature. The time for an initially uncharged ensemble of particles to reach the steady state distribution is directly proportional to $CT_{e}$.

  4. Charging of heated colloidal particles using the electrolyte Seebeck effect.

    Science.gov (United States)

    Majee, Arghya; Würger, Alois

    2012-03-16

    We propose a novel actuation mechanism for colloids, which is based on the Seebeck effect of the electrolyte solution: Laser heating of a nonionic particle accumulates in its vicinity a net charge Q, which is proportional to the excess temperature at the particle surface. The corresponding long-range thermoelectric field E is proportional to 1/r(2) provides a tool for controlled interactions with nearby beads or with additional molecular solutes. An external field E(ext) drags the thermocharged particle at a velocity that depends on its size and absorption properties; the latter point could be particularly relevant for separating carbon nanotubes according to their electronic band structure.

  5. Particle acceleration and radiation in Pulsar Wind Nebulae

    CERN Document Server

    Amato, Elena

    2015-01-01

    Pulsar Wind Nebulae are the astrophysical sources that host the most relativistic shocks in Nature and the only Galactic sources in which we have direct evidence of PeV particles. These facts make them very interesting from the point of view of particle acceleration physics, and their proximity and brightness make them a place where fundamental processes common to different classes of relativistic sources have a better chance to be understood. I will discuss how well we understand the physics of Pulsar Wind Nebulae, describing recent progress and highlighting the main open questions. I will be mostly concerned with the subject of particle acceleration, but, as we will see, in order to clarify the physics of this process, it is important to determine the conditions of the plasma in the nebula. These in turn can only be constrained through detailed modelling of the PWN dynamics and radiation. The shock in the Crab Nebula is probably the most efficient accelerator known, both in terms of conversion of the flow e...

  6. Monitoring of Hadrontherapy Treatments by Means of Charged Particle Detection.

    Science.gov (United States)

    Muraro, Silvia; Battistoni, Giuseppe; Collamati, Francesco; De Lucia, Erika; Faccini, Riccardo; Ferroni, Fernando; Fiore, Salvatore; Frallicciardi, Paola; Marafini, Michela; Mattei, Ilaria; Morganti, Silvio; Paramatti, Riccardo; Piersanti, Luca; Pinci, Davide; Rucinski, Antoni; Russomando, Andrea; Sarti, Alessio; Sciubba, Adalberto; Solfaroli-Camillocci, Elena; Toppi, Marco; Traini, Giacomo; Voena, Cecilia; Patera, Vincenzo

    2016-01-01

    The interaction of the incoming beam radiation with the patient body in hadrontherapy treatments produces secondary charged and neutral particles, whose detection can be used for monitoring purposes and to perform an on-line check of beam particle range. In the context of ion-therapy with active scanning, charged particles are potentially attractive since they can be easily tracked with a high efficiency, in presence of a relatively low background contamination. In order to verify the possibility of exploiting this approach for in-beam monitoring in ion-therapy, and to guide the design of specific detectors, both simulations and experimental tests are being performed with ion beams impinging on simple homogeneous tissue-like targets (PMMA). From these studies, a resolution of the order of few millimeters on the single track has been proven to be sufficient to exploit charged particle tracking for monitoring purposes, preserving the precision achievable on longitudinal shape. The results obtained so far show that the measurement of charged particles can be successfully implemented in a technology capable of monitoring both the dose profile and the position of the Bragg peak inside the target and finally lead to the design of a novel profile detector. Crucial aspects to be considered are the detector positioning, to be optimized in order to maximize the available statistics, and the capability of accounting for the multiple scattering interactions undergone by the charged fragments along their exit path from the patient body. The experimental results collected up to now are also valuable for the validation of Monte Carlo simulation software tools and their implementation in Treatment Planning Software packages.

  7. Monitoring of hadrontherapy treatments by means of charged particle detection

    Directory of Open Access Journals (Sweden)

    Giuseppe Battistoni

    2016-08-01

    Full Text Available The interaction of the incoming beam radiation with the patient body in hadrontherapy treatments produces secondary charged and neutral particles, whose detection can be used for monitoring purposes and to perform an on-line check of beam particle range. Charged particles are potentially attractive since they can be easily tracked with a high efficiency, in presence of a relatively low background contamination. In order to verify the possibility of exploiting this approach for in-beam monitoring in hadrontherapy, and to guide the design of specific detectors, both simulations and experimental tests are being performed with ion beams impinging on simple homogeneous tissue-like targets (PMMA. An important outcome of these studies is that the experimental single track resolution needed for charged particle based monitoring applications can be safely of the order of few millimeters, without spoiling the precision achievable on longitudinal shape. The results obtained so far show that the measurement of charged particles can be successfully implemented in a technology capable of monitoring the dose profile and the position of the Bragg peak inside the target and finally lead to the design of a novel profile detector. Crucial aspects to be considered are the detector positioning, to be optimized in order to maximize the available statistics, and the capability of accounting for the multiple scattering interactions undergone by the charged fragments along their exit path from the patient body. The experimental results collected up to now are also valuable for the validation of Monte Carlo simulation software tools and their implementation in Treatment Planning Software packages.

  8. Monitoring of Hadrontherapy Treatments by Means of Charged Particle Detection

    Science.gov (United States)

    Muraro, Silvia; Battistoni, Giuseppe; Collamati, Francesco; De Lucia, Erika; Faccini, Riccardo; Ferroni, Fernando; Fiore, Salvatore; Frallicciardi, Paola; Marafini, Michela; Mattei, Ilaria; Morganti, Silvio; Paramatti, Riccardo; Piersanti, Luca; Pinci, Davide; Rucinski, Antoni; Russomando, Andrea; Sarti, Alessio; Sciubba, Adalberto; Solfaroli-Camillocci, Elena; Toppi, Marco; Traini, Giacomo; Voena, Cecilia; Patera, Vincenzo

    2016-01-01

    The interaction of the incoming beam radiation with the patient body in hadrontherapy treatments produces secondary charged and neutral particles, whose detection can be used for monitoring purposes and to perform an on-line check of beam particle range. In the context of ion-therapy with active scanning, charged particles are potentially attractive since they can be easily tracked with a high efficiency, in presence of a relatively low background contamination. In order to verify the possibility of exploiting this approach for in-beam monitoring in ion-therapy, and to guide the design of specific detectors, both simulations and experimental tests are being performed with ion beams impinging on simple homogeneous tissue-like targets (PMMA). From these studies, a resolution of the order of few millimeters on the single track has been proven to be sufficient to exploit charged particle tracking for monitoring purposes, preserving the precision achievable on longitudinal shape. The results obtained so far show that the measurement of charged particles can be successfully implemented in a technology capable of monitoring both the dose profile and the position of the Bragg peak inside the target and finally lead to the design of a novel profile detector. Crucial aspects to be considered are the detector positioning, to be optimized in order to maximize the available statistics, and the capability of accounting for the multiple scattering interactions undergone by the charged fragments along their exit path from the patient body. The experimental results collected up to now are also valuable for the validation of Monte Carlo simulation software tools and their implementation in Treatment Planning Software packages. PMID:27536555

  9. Charged Q-balls and boson stars and dynamics of charged test particles

    CERN Document Server

    Brihaye, Yves; Hartmann, Betti

    2014-01-01

    We construct electrically charged Q-balls and boson stars in a model with a scalar self-interaction potential resulting from gauge mediated supersymmetry breaking. We discuss the properties of these solutions in detail and emphasize the differences to the uncharged case. We observe that $Q$-balls can only be constructed up to a maximal value of the charge of the scalar field, while for boson stars the interplay between the attractive gravitational force and the repulsive electromagnetic force determines their behaviour. We also study the motion of charged, massive test particles in the space-time of boson stars. We find that in contrast to charged black holes the motion of charged test particles in charged boson star space-times is planar, but that the presence of the scalar field plays a crucial r\\^ole for the qualitative features of the trajectories. Applications of this test particle motion can be made in the study of extreme-mass ratio inspirals (EMRIs) as well as astrophysical plasmas relevant e.g. in th...

  10. Space charge distribution measurement methods and particle loaded insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Hole, S [Laboratoire des Instruments et Systemes d' Ile de France, Universite Pierre et Marie Curie-Paris6, 10 rue Vauquelin, 75005 Paris (France); Sylvestre, A [Laboratoire d' Electrostatique et des Materiaux Dielectriques, CNRS UMR5517, 25 avenue des Martyrs, BP 166, 38042 Grenoble cedex 9 (France); Lavallee, O Gallot [Laboratoire d' Etude Aerodynamiques, CNRS UMR6609, boulevard Marie et Pierre Curie, Teleport 2, BP 30179, 86962 Futuroscope, Chasseneuil (France); Guillermin, C [Schneider Electric Industries SAS, 22 rue Henry Tarze, 38000 Grenoble (France); Rain, P [Laboratoire d' Electrostatique et des Materiaux Dielectriques, CNRS UMR5517, 25 avenue des Martyrs, BP 166, 38042 Grenoble cedex 9 (France); Rowe, S [Schneider Electric Industries SAS, 22 rue Henry Tarze, 38000 Grenoble (France)

    2006-03-07

    In this paper the authors discuss the effects of particles (fillers) mixed in a composite polymer on the space charge measurement techniques. The origin of particle-induced spurious signals is determined and silica filled epoxy resin is analysed using the laser-induced-pressure-pulse (LIPP) method, the pulsed-electro-acoustic (PEA) method and the laser-induced-thermal-pulse (LITP) method. A spurious signal identified as the consequence of a piezoelectric effect of some silica particles is visible for all the method. Moreover, space charges are clearly detected at the epoxy/silica interface after a 10 kV mm{sup -1} poling at room temperature for 2 h.

  11. Brownian Dynamics of charged particles in a constant magnetic field

    CERN Document Server

    Hou, L J; Piel, A; Shukla, P K

    2009-01-01

    Numerical algorithms are proposed for simulating the Brownian dynamics of charged particles in an external magnetic field, taking into account the Brownian motion of charged particles, damping effect and the effect of magnetic field self-consistently. Performance of these algorithms is tested in terms of their accuracy and long-time stability by using a three-dimensional Brownian oscillator model with constant magnetic field. Step-by-step recipes for implementing these algorithms are given in detail. It is expected that these algorithms can be directly used to study particle dynamics in various dispersed systems in the presence of a magnetic field, including polymer solutions, colloidal suspensions and, particularly complex (dusty) plasmas. The proposed algorithms can also be used as thermostat in the usual molecular dynamics simulation in the presence of magnetic field.

  12. Diagnostic and Detectors for Charging and Damage of Dielectrics in High-gradient Accelerators

    CERN Document Server

    Shchelkunov, S V; Hirshfield, J L

    2015-01-01

    The research is aimed to address issues of analysis and mitigation of high repetition rate effects in Dielectric Wakefield Accelerators, and more specifically, to study charging rate and charge distribution in a thin walled dielectric wakefield accelerator from a passing charge bunch and the physics of conductivity and discharge phenomena in dielectric materials useful for such accelerator applications. The issue is the role played by the beam halo and intense wakefields in charging of the dielectric, possibly leading to undesired deflection of charge bunches and degradation of the dielectric material. The detector that was developed is based on measurement of the complex electrical conductivity, which would appear as a transient phenomenon accompanying the passage of one or more charge bunches, by observing the change of complex admittance of a resonant microwave cavity that is fitted around the dielectric tubing. The detector also can detect permanent damage to the material. During initial stage of developm...

  13. AXEL-2015 - Introduction To Particle Accelerators | starting 19 January

    CERN Multimedia

    2014-01-01

    CERN Technical Training 2015: Learning for the LHC AXEL-2015 is a lecture series on particle accelerators, given at CERN within the framework of the 2014 Technical Training Programme. As part of the BE Department’s Operations Group Shutdown Lecture series, the general accelerator physics module has been organised since 2003 as a joint venture between the BE Department and Technical Training, and is open to the general CERN community. The AXEL-2015 course is designed for technicians who are operating an accelerator or whose work is closely linked to accelerators, but it is also open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge of accelerators. However, some basic knowledge of trigonometry, matrices and differential equations and some basic knowledge of magnetism would be an advantage. The series will consists of 10 one-hour sessions (Monday 19 January 2015 – Friday 23 January 2015, from 9 a.m. to 10.15 a.m. and ...

  14. Technical Training: AXEL-2005 - Introduction to Particle Accelerators

    CERN Multimedia

    Monique Duval

    2005-01-01

    CERN Technical Training 2005: Learning for the LHC! AXEL-2005 is a course series on particle accelerators, given at CERN within the framework of the 2005 Technical Training Programme. Known in the past as the PS Complex Operation Course (or the 'PS Shutdown Course', now AB/OP), the general accelerator physics section is organised since 2003 as a joint venture between the AB department and Technical Training, and is open to a wider CERN community. The AXEL-2005 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is open to all people (technicians, engineers, physicists) interested in this field. The course does not require any prior knowledge on accelerators. However, some basic knowledge on trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course will be given in French on course supports in English; questions and answers possible in both languages. AXEL-2005 - I...

  15. Technical Training: AXEL-2005: Introduction to Particle Accelerators

    CERN Multimedia

    Monique Duval

    2005-01-01

    CERN Technical Training 2005: Learning for the LHC! AXEL-2005 is a course series on particle accelerators, given at CERN within the framework of the 2005 Technical Training Programme. Known in the past as the PS Complex Operation Course (or the 'PS Shutdown Course', now AB/OP), the general accelerator physics section is organised since 2003 as a joint venture between the AB department and Technical Training, and is open to a wider CERN community. The AXEL-2005 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is open to all people (technicians, engineers, physicists) interested in this field. The course does not require any prior knowledge on accelerators. However, some basic knowledge on trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) during the week 14-18 March 2005, given in Fr...

  16. Technical training: AXEL-2009 - Introduction to Particle Accelerators

    CERN Multimedia

    HR Department

    2008-01-01

    CERN Technical Training 2009: Learning for the LHC! AXEL-2009 is a course series on particle accelerators, given at CERN within the framework of the 2009 Technical Training Program. Known in the past as the PS Complex Operation Course (or the ‘PS Shutdown Course’), the general accelerator physics module is organized since 2003 as a joint venture between the AB department and Technical Training, and is open to a wider CERN community. The AXEL-2009 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge on accelerators. However, some basic knowledge on trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) from the 19th – 23rd of January 2009, and given in English with...

  17. Technical training: AXEL-2006 - Introduction to Particle Accelerators

    CERN Document Server

    Davide Vitè

    2006-01-01

    CERN Technical Training 2006: Learning for the LHC! AXEL-2006 is a course series on particle accelerators, given at CERN within the framework of the 2006 Technical Training Programme. Known in the past as the PS Complex Operation Course (or the 'PS Shutdown Course'), the general accelerator physics module is organised since 2003 as a joint venture between the AB department and Technical Training, and is open to a wider CERN community. The AXEL-2006 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge on accelerators. However, some basic knowledge on trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) during the week 6-10 February March 2006, and given in English...

  18. Technical training: AXEL-2009 - Introduction to Particle Accelerators

    CERN Document Server

    HR Department

    2009-01-01

    CERN Technical Training 2009: Learning for the LHC! AXEL-2009 is a course series on particle accelerators, given at CERN within the framework of the 2009 Technical Training Program. Known in the past as the PS Complex Operation Course (or the ‘PS Shutdown Course’), the general accelerator physics module as been organized since 2003 as a joint venture between the AB Department and Technical Training Service, and is open to a wider CERN community. The AXEL-2009 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is also open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge of accelerators. However, some basic knowledge of trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) from 19 to 23 January 2009, and will be given i...

  19. Technical training: AXEL-2010 - Introduction to particle accelerators

    CERN Multimedia

    HR Department

    2010-01-01

    CERN Technical Training 2010: Learning for the LHC! AXEL-2010 is a course series on particle accelerators, given at CERN within the framework of the 2010 Technical Training Program. Known in the past as the PS Complex Operation Course (or the ‘PS Shutdown Course’), the general accelerator physics module is organized since 2003 as a joint venture between the BE department and Technical Training, and is open to a wider CERN community. The AXEL-2010 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge on accelerators. However, some basic knowledge on trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) from the 1st – 5th of February 201...

  20. Technical training: AXEL-2011 - Introduction to Particle Accelerators

    CERN Multimedia

    HR Department

    2010-01-01

    CERN Technical Training 2011: Learning for the LHC! AXEL-2011 is a course series on particle accelerators, given at CERN within the framework of the 2011 Technical Training Program. As part of the BE Department’s Operation Group Shutdown Lecture series, the general accelerator physics module has been organized since 2003 as a joint venture between the BE Department and Technical Training, and is open to a wider CERN community. The AXEL-2011 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is also open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge of accelerators. However, some basic knowledge of trigonometry, matrices and differential equations, and some basic knowledge of magnetism would be an advantage. The series will be composed of 10 one-hour courses (Monday 10.01.2011 – Fri 14.01.2011, from 09:00 to 10:30 and from 14:00 to 15:...

  1. Free charged particle behavior in intense laser fields

    Science.gov (United States)

    Fradkin, D. M.

    1984-03-01

    Theoretical studies were performed examining the effect of intense laser fields, together with auxiliary electromagnetic field configuration, on the behavior of otherwise free charged particles. The Lorentz-Dirac classical equation was employed to determine the effect of radiation reaction on the transfer of asymptotic energy momentum to a particle by a single intense plane wave pulse. The added effect due to a uniform magnetic field along the pulse propagation direction was determined. Single particle Dirac theory was employed to analyze particle polarization direction changes in a quantum-mechanical model. The general nature of the Lorentz transformation as a active transformation connecting initial and final states was determined, in which a single state characterization parameter was left unspecified. Analytic and computer studies were made of the effect of two simultaneous laser pulses, propagating in opposite directions on particle dynamics.

  2. Effects of dispersive wave modes on charged particles transport

    CERN Document Server

    Schreiner, Cedric

    2015-01-01

    The transport of charged particles in the heliosphere and the interstellar medium is governed by the interaction of particles and magnetic irregularities. For the transport of protons a rather simple model using a linear Alfv\\'en wave spectrum which follows the Kolmogorov distribution usually yields good results. Even magnetostatic spectra may be used. For the case of electron transport, particles will resonate with the high-k end of the spectrum. Here the magnetic fluctuations do not follow the linear dispersion relation, but the kinetic regime kicks in. We will discuss the interaction of fluctuations of dispersive waves in the kinetic regime using a particle-in-cell code. Especially the scattering of particles following the idea of Lange et al. (2013) and its application to PiC codes will be discussed. The effect of the dispersive regime on the electron transport will be discussed in detail.

  3. Improved techniques of impedance calculation and localization in particle accelerators

    CERN Document Server

    Biancacci, Nicolò; Migliorati, Mauro; Métral, Elias; Salvant, Benoit

    In this thesis we mainly focus on particle accelerators applied to high energy physics research where a fundamental parameter, the luminosity, is maximized in order to increase the rate of particle collisions useful to particle physicists. One way to increase this parameter is to increase the intensity of the circulating beams which is limited by the onset of collective effects that may drive the beam unstable and eventually provoke beam losses or reduce the beam quality required by the particle physics experiments. One major cause of collective effects is the beam coupling impedance, a quantity that quantifies the effect of the fields scattered by a beam passing through any accelerator device. The development of an impedance budget is required in those machines that are planning substantial upgrades as shown in this thesis for the CERN PS case. The main source of impedance in the CERN LHC are the collimators. Within an impedance reduction perspective, in order to reach the goals of the planned upgrades, it ...

  4. Charge neutrality of fine particle (dusty) plasmas and fine particle cloud under gravity

    Science.gov (United States)

    Totsuji, Hiroo

    2017-03-01

    The enhancement of the charge neutrality due to the existence of fine particles is shown to occur generally under microgravity and in one-dimensional structures under gravity. As an application of the latter, the size and position of fine particle clouds relative to surrounding plasmas are determined under gravity.

  5. Accelerated simulation of stochastic particle removal processes in particle-resolved aerosol models

    Science.gov (United States)

    Curtis, J. H.; Michelotti, M. D.; Riemer, N.; Heath, M. T.; West, M.

    2016-10-01

    Stochastic particle-resolved methods have proven useful for simulating multi-dimensional systems such as composition-resolved aerosol size distributions. While particle-resolved methods have substantial benefits for highly detailed simulations, these techniques suffer from high computational cost, motivating efforts to improve their algorithmic efficiency. Here we formulate an algorithm for accelerating particle removal processes by aggregating particles of similar size into bins. We present the Binned Algorithm for particle removal processes and analyze its performance with application to the atmospherically relevant process of aerosol dry deposition. We show that the Binned Algorithm can dramatically improve the efficiency of particle removals, particularly for low removal rates, and that computational cost is reduced without introducing additional error. In simulations of aerosol particle removal by dry deposition in atmospherically relevant conditions, we demonstrate about 50-times increase in algorithm efficiency.

  6. Public Lecture | Philipe Lebrun | "Particle accelerators" | 2 September

    CERN Document Server

    2014-01-01

    "Les accélérateurs de particules : vecteurs de découvertes, moteurs de développement", by Dr. Philippe Lebrun.   2 September 2014 - 7:30 p.m. Globe of Science and Innovation Particle accelerators have been used in fundamental research for over a century, allowing physicists to discover elementary particles and study them at increasingly smaller scales. Making use of emerging technologies whose progress they helped to stimulate, they developed exponentially throughout the 20th century to become major tools for research today, not only in particle physics but also – as powerful radiation sources for probing matter – in atomic and molecular physics, condensed matter physics and materials science. They have also found applications in society, where they are increasingly used in a wide range of fields including applied sciences, medicine (research and clinical applications) and industry. The lecture will cover examples ...

  7. Spectra of accelerated particles at supernova shocks in the presence of neutral hydrogen: the case of Tycho

    CERN Document Server

    Morlino, G

    2015-01-01

    The presence of neutral hydrogen in the shock proximity changes the structure of the shock and affects the spectra of particles accelerated through the first order Fermi mechanism. This phenomenon has profound implications for the interpretation of the multifrequency spectra of radiation from supernova remnants. Neutrals that undergo charge exchange with hot ions downstream of the shock may result in fast neutrals moving towards the upstream gas, where they can suffer additional charge exchange or ionisation reactions, thereby depositing energy and momentum upstream. Here we discuss the implications of this neutral return flux, already predicted in our previous work on neutral mediated supernova shocks and show how the spectra of accelerated particles turn out to be appreciably steeper than $p^{-4}$, thereby affecting the gamma ray spectra from supernova remnants in general and from Tycho specifically. The theory that describes non-linear diffusive shock acceleration in the presence of neutral hydrogen has be...

  8. Solar Energetic Particle drifts and the energy dependence of 1 AU charge states

    CERN Document Server

    Dalla, S; Battarbee, M

    2016-01-01

    The event-averaged charge state of heavy ion Solar Energetic Particles (SEPs), measured at 1 AU from the Sun, typically increases with the ions' kinetic energy. The origin of this behaviour has been ascribed to processes taking place within the acceleration region. In this paper we study the propagation through interplanetary space of SEP Fe ions, injected near the Sun with a variety of charge states that are uniformly distributed in energy, by means of a 3D test particle model. In our simulations, due to gradient and curvature drifts associated with the Parker spiral magnetic field, ions of different charge propagate with very different efficiencies to an observer that is not magnetically well connected to the source region. As a result we find that, for many observer locations, the 1 AU event-averaged charge state , as obtained from our model, displays an increase with particle energy E, in qualitative agreement with spacecraft observations. We conclude that drift-associated propagation is a possible explan...

  9. Solar Energetic Particle Drifts and the Energy Dependence of 1 AU Charge States

    Science.gov (United States)

    Dalla, S.; Marsh, M. S.; Battarbee, M.

    2017-01-01

    The event-averaged charge state of heavy ion solar energetic particles (SEPs), measured at 1 au from the Sun, typically increases with the ions’ kinetic energy. The origin of this behavior has been ascribed to processes taking place within the acceleration region. In this paper we study the propagation through interplanetary space of SEP Fe ions, injected near the Sun with a variety of charge states that are uniformly distributed in energy, by means of a 3D test particle model. In our simulations, due to gradient and curvature drifts associated with the Parker spiral magnetic field, ions of different charge propagate with very different efficiencies to an observer that is not magnetically well connected to the source region. As a result we find that, for many observer locations, the 1 au event-averaged charge state , as obtained from our model, displays an increase with particle energy E, in qualitative agreement with spacecraft observations. We conclude that drift-associated propagation is a possible explanation for the observed distribution of versus E in SEP events, and that the distribution measured in interplanetary space cannot be taken to represent that at injection.

  10. Acceleration of low-energy protons and alpha particles at interplanetary shock waves

    Science.gov (United States)

    Scholer, M.; Hovestadt, D.; Ipavich, F. M.; Gloeckler, G.

    1983-01-01

    The low-energy protons and alpha particles in the energy range 30 keV/charge to 150 keV/charge associated with three different interplanetary shock waves in the immediate preshock and postshock region are studied using data obtained by the ISEE 3. The spatial distributions in the preshock and postshock medium are presented, and the dependence of the phase space density at different energies on the distance from the shock and on the form of the distribution function of both species immediately at the shock is examined. It is found that in the preshock region the particles are flowing in the solar wind frame of reference away from the shock and in the postshock medium the distribution is more or less isotropic in this frame of reference. The distribution function in the postshock region can be represented by a power law in energy which has the same spectral exponent for both protons and alpha particles. It is concluded that the first-order Fermi acceleration process can consistently explain the data, although the spectra of diffuse bow shock associated particles are different from the spectra of the interplanetary shock-associated particles in the immediate vicinity of the shock. In addition, the mean free path of the low energy ions in the preshock medium is found to be considerably smaller than the mean free path determined by the turbulence of the background interplanetary medium.

  11. Technical training: AXEL-2008 - Introduction to Particle Accelerators

    CERN Document Server

    2008-01-01

    CERN Technical Training 2008: Learning for the LHC! AXEL-2008 is a course series on particle accelerators, given at CERN within the framework of the AB Operation Group Shut-down Lectures. Since 2003, this course is organized as a joint venture between the AB department and Technical Training, and is open to a wider CERN community. The AXEL-2008 course series is designed for technicians who are operating an accelerator, or whose work is closely linked to accelerators, but it is open to technicians, engineers, and physicists interested in this field. The course does not require any prior knowledge on accelerators. However, some basic knowledge on trigonometry, matrices and differential equations, and some basic notions of magnetism would be an advantage. The course series will be composed of 10 one-hour lectures (mornings and afternoons) from the 29th of January to the 1st February 2008, and given in English with questions and answers also possible in French. The lecturer is Rende Steerenberg, engineer and sup...

  12. Modelling die filling with charged particles using DEM/CFD

    Institute of Scientific and Technical Information of China (English)

    Emmanuel Nkem Nwose; Chunlei Pei; Chuan-Yu Wu

    2012-01-01

    The effects of electrostatic charge on powder flow behaviour during die filling in a vacuum and in air were analysed using a coupled discrete element method and computational fluid dynamics (DEM/CFD) code,in which long range electrostatic interactions were implemented.The present 2D simulations revealed that both electrostatic charge and the presence of air can affect the powder flow behaviour during die filling.It was found that the electrostatic charge inhibited the flow of powders into the die and induced a loose packing structure.At the same filling speed,increasing the electrostatic charge led to a decrease in the fill ratio which quantifies the volumetric occupancy of powder in the die.In addition,increasing the shoe speed caused a further decrease in the fill ratio,which was characterised using the concept of critical filling speed.When the electrostatic charge was low,the air/particle interaction was strong so that a lower critical filling speed was obtained for die filling in air than in a vacuum.With high electrostatic charge,the electrostatic interactions became dominant.Consequently,similar fill ratio and critical filling speed were obtained for die filling in air and in a vacuum.

  13. Low energy charged particles interacting with amorphous solid water layers

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Yonatan; Asscher, Micha [Institute of Chemistry, Hebrew University of Jerusalem, Edmund J. Safra Campus, Givat-Ram, Jerusalem 91904 (Israel)

    2012-04-07

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 {mu}A) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 {+-} 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  14. Low energy charged particles interacting with amorphous solid water layers

    Science.gov (United States)

    Horowitz, Yonatan; Asscher, Micha

    2012-04-01

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 μA) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 ± 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  15. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2003-01-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EIi is of the order of (2-5 x1016 ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  16. The Particle Accelerator Simulation Code PyORBIT

    Energy Technology Data Exchange (ETDEWEB)

    Gorlov, Timofey V [ORNL; Holmes, Jeffrey A [ORNL; Cousineau, Sarah M [ORNL; Shishlo, Andrei P [ORNL

    2015-01-01

    The particle accelerator simulation code PyORBIT is presented. The structure, implementation, history, parallel and simulation capabilities, and future development of the code are discussed. The PyORBIT code is a new implementation and extension of algorithms of the original ORBIT code that was developed for the Spallation Neutron Source accelerator at the Oak Ridge National Laboratory. The PyORBIT code has a two level structure. The upper level uses the Python programming language to control the flow of intensive calculations performed by the lower level code implemented in the C++ language. The parallel capabilities are based on MPI communications. The PyORBIT is an open source code accessible to the public through the Google Open Source Projects Hosting service.

  17. Particle Acceleration at Shocks: Insights from Supernova Remnant Shocks

    Indian Academy of Sciences (India)

    T. W. Jones

    2011-12-01

    I review some basic properties of diffusive shock acceleration (DSA) in the context of young supernova remnants (SNRs). I also point out some key differences with cosmological, cluster-related shocks. DSA seems to be very efficient in strong, young SNR shocks. Provided the magnetic fields exceed some hundreds of Gauss (possibly amplified by CR related dynamics), these shocks can accelerate cosmic ray hadrons to PeV energies in the time available to them. Electron energies, limited by radiative losses, are likely limited to the TeV range. Injection of fresh particles at these shocks is poorly understood, but hadrons are much more easily injected than the more highly magnetized electrons. That seems supported by observational data, as well. So, while CR protons in young SNRs may play very major roles in the SNR evolution, the CR electron populations have minimal such impact, despite their observational importance.

  18. Laser-driven particle acceleration towards radiobiology and medicine

    CERN Document Server

    2016-01-01

    This book deals with the new method of laser-driven acceleration for application to radiation biophysics and medicine. It provides multidisciplinary contributions from world leading scientist in order to assess the state of the art of innovative tools for radiation biology research and medical applications of ionizing radiation. The book contains insightful contributions on highly topical aspects of spatio-temporal radiation biophysics, evolving over several orders of magnitude, typically from femtosecond and sub-micrometer scales. Particular attention is devoted to the emerging technology of laser-driven particle accelerators and their applicatio to spatio-temporal radiation biology and medical physics, customization of non-conventional and selective radiotherapy and optimized radioprotection protocols.

  19. Permittivity and permeability measurements methods for particle accelerator related materials

    CERN Document Server

    Vollinger, C; Jensen, E

    2014-01-01

    For the special requirements related to particle accelerators, knowledge of the different material parameters of dielectrics and other materials are needed in order to carry out simulations during the design process of accelerator components. This includes also properties of magnetically biased ferrites of which usually little information is available about material characteristics, especially in magnetic bias fields. Several methods of measurement are discussed and compared of which some require delicate sample preparation whereas others can work with unmodified material shapes that makes those methods also suited for acceptance checks on incoming materials delivered by industry. Applications include characterization of different materials, as absorbers in which dielectric losses play an increasing role, as well as low frequency measurements on ferrites that are used for tunable cavities. We present results obtained from both broadband and resonant measurements on different materials determined in the same s...

  20. Gas-silicon detector telescope for charged particle spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Honkanen, A.; Oinonen, M.; Aeystoe, J. [Jyvaeskylae Univ. (Finland). Dept. of Physics; Eskola, K. [Helsinki Univ. (Finland). Dept. of Phys.; Jokinen, A. [PPE Division, CERN, CH-1211 Geneva 23 (Switzerland); ISOLDE Collaboration

    1997-08-11

    A gas-silicon detector telescope for charged particle spectroscopy has been constructed and tested. The lower detection limits were determined to be 155 keV for protons, 180 keV for deuterons and 350 keV for alpha particles. Typical energy resolution of the telescope measured for beta-delayed protons is 20 keV. Time resolution for the signals of the telescope was measured to be less than 10 ns. Examples of using the detector telescope in detection of beta-delayed proton activities are presented. (orig.).

  1. Visual Basic VPython Interface: Charged Particle in a Magnetic Field

    Science.gov (United States)

    Prayaga, Chandra

    2006-12-01

    A simple Visual Basic (VB) to VPython interface is described and illustrated with the example of a charged particle in a magnetic field. This interface allows data to be passed to Python through a text file read by Python. The first component of the interface is a user-friendly data entry screen designed in VB, in which the user can input values of the charge, mass, initial position and initial velocity of the particle, and the magnetic field. Next, a command button is coded to write these values to a text file. Another command button starts the VPython program, which reads the data from the text file, numerically solves the equation of motion, and provides the 3d graphics animation. Students can use the interface to run the program several times with different data and observe changes in the motion.

  2. Interdefect charge exchange in silicon particle detectors at cryogenic temperatures

    CERN Document Server

    MacEvoy, B; Hall, G; Moscatelli, F; Passeri, D; Santocchia, A

    2002-01-01

    Silicon particle detectors in the next generation of experiments at the CERN Large Hadron Collider will be exposed to a very challenging radiation environment. The principal obstacle to long-term operation arises from changes in detector doping concentration (N/sub eff/), which lead to an increase in the bias required to deplete the detector and hence achieve efficient charge collection. We have previously presented a model of interdefect charge exchange between closely spaced centers in the dense terminal clusters formed by hadron irradiation. This manifestly non-Shockley-Read-Hall (SRH) mechanism leads to a marked increase in carrier generation rate and negative space charge over the SRH prediction. There is currently much interest in the subject of cryogenic detector operation as a means of improving radiation hardness. Our motivation, however, is primarily to investigate our model further by testing its predictions over a range of temperatures. We present measurements of spectra from /sup 241/Am alpha par...

  3. Stopping power of charged particles due to ion wave excitations

    Science.gov (United States)

    Nitta, H.; Muroki, C.; Nambu, M.

    2002-08-01

    Stopping power due to ion wave excitations is derived for a charged particle moving in a two-component plasma. Unlike previous theories based on ion-acoustic-wave approximation (IAWA), the excitation of short-wavelength ion waves is taken into account. The obtained stopping power has a magnitude larger than that of IAWA. Stopping power at subsonic velocities, where stopping power in IAWA disappears, is even larger than that of supersonic velocities.

  4. Stopping power of charged particles due to ion wave excitations.

    Science.gov (United States)

    Nitta, H; Muroki, C; Nambu, M

    2002-08-01

    Stopping power due to ion wave excitations is derived for a charged particle moving in a two-component plasma. Unlike previous theories based on ion-acoustic-wave approximation (IAWA), the excitation of short-wavelength ion waves is taken into account. The obtained stopping power has a magnitude larger than that of IAWA. Stopping power at subsonic velocities, where stopping power in IAWA disappears, is even larger than that of supersonic velocities.

  5. New modes of particle accelerations techniques and sources. Formal report

    Energy Technology Data Exchange (ETDEWEB)

    Parsa, Z. [ed.

    1996-12-31

    This Report includes copies of transparencies and notes from the presentations made at the Symposium on New Modes of Particle Accelerations - Techniques and Sources, August 19-23, 1996 at the Institute for Theoretical Physics, University of California, Santa Barbara California, that was made available by the authors. Editing, reduction and changes to the authors contributions were made only to fulfill the printing and publication requirements. We would like to take this opportunity and thank the speakers for their informative presentations and for providing copies of their transparencies and notes for inclusion in this Report.

  6. Laser-Accelerated Proton Beams as a New Particle Source

    OpenAIRE

    Nürnberg, Frank

    2010-01-01

    The framework of this thesis is the investigation of the generation of proton beams using high-intensity laser pulses. Today's high power, ultrashort pulse laser systems are capable of achieving laser intensities up to 10^21 W/cm^2. When focused onto thin foil targets, extremely high field gradients of the order of TV/m are produced on the rear side of the target resulting in the acceleration of protons to multi-MeV energies with an exponential spectrum including up to 10^13 particles. This a...

  7. Electromagnetic radiation of charged particles in stochastic motion

    Energy Technology Data Exchange (ETDEWEB)

    Harko, Tiberiu [Babes-Bolyai University, Department of Physics, Cluj-Napoca (Romania); University College London, Department of Mathematics, London (United Kingdom); Mocanu, Gabriela [Astronomical Institute of the Romanian Academy, Cluj-Napoca (Romania)

    2016-03-15

    The study of the Brownian motion of a charged particle in electric and magnetic fields has many important applications in plasma and heavy ions physics, as well as in astrophysics. In the present paper we consider the electromagnetic radiation properties of a charged non-relativistic particle in the presence of electric and magnetic fields, of an exterior non-electromagnetic potential, and of a friction and stochastic force, respectively. We describe the motion of the charged particle by a Langevin and generalized Langevin type stochastic differential equation. We investigate in detail the cases of the Brownian motion with or without memory in a constant electric field, in the presence of an external harmonic potential, and of a constant magnetic field. In all cases the corresponding Langevin equations are solved numerically, and a full description of the spectrum of the emitted radiation and of the physical properties of the motion is obtained. The power spectral density of the emitted power is also obtained for each case, and, for all considered oscillating systems, it shows the presence of peaks, corresponding to certain intervals of the frequency. (orig.)

  8. Collisionless shocks in space plasmas structure and accelerated particles

    CERN Document Server

    Burgess, David

    2015-01-01

    Shock waves are an important feature of solar system plasmas, from the solar corona out to the edge of the heliosphere. This engaging introduction to collisionless shocks in space plasmas presents a comprehensive review of the physics governing different types of shocks and processes of particle acceleration, from fundamental principles to current research. Motivated by observations of planetary bow shocks, interplanetary shocks and the solar wind termination shock, it emphasises the physical theory underlying these shock waves. Readers will develop an understanding of the complex interplay between particle dynamics and the electric and magnetic fields that explains the observations of in situ spacecraft. Written by renowned experts in the field, this up-to-date text is the ideal companion for both graduate students new to heliospheric physics and researchers in astrophysics who wish to apply the lessons of solar system shocks to different astrophysical environments.

  9. Black holes are neither particle accelerators nor dark matter probes.

    Science.gov (United States)

    McWilliams, Sean T

    2013-01-04

    It has been suggested that maximally spinning black holes can serve as particle accelerators, reaching arbitrarily high center-of-mass energies. Despite several objections regarding the practical achievability of such high energies, and demonstrations past and present that such large energies could never reach a distant observer, interest in this problem has remained substantial. We show that, unfortunately, a maximally spinning black hole can never serve as a probe of high energy collisions, even in principle and despite the correctness of the original diverging energy calculation. Black holes can indeed facilitate dark matter annihilation, but the most energetic photons can carry little more than the rest energy of the dark matter particles to a distant observer, and those photons are actually generated relatively far from the black hole where relativistic effects are negligible. Therefore, any strong gravitational potential could probe dark matter equally well, and an appeal to black holes for facilitating such collisions is unnecessary.

  10. Particle transport in microturbulence and acceleration performances of relativistic shocks

    CERN Document Server

    Plotnikov, Illya; Lemoine, Martin

    2012-01-01

    Collisionless relativistic shocks have been the focus of intense theoretical and numerical investigations and these interesting physics have a direct impact on the generation of energetic particles and the interpretation of gamma ray spectra. The Fermi acceleration process that takes place in these shocks is intimately linked with the excitation of micro-turbulence responsible for the shock formation, electron heating and supra-thermal tail generation that in turn excites micro-turbulence, developing thus a self-sustaining phenomenon. In this paper we discuss the development of the micro-turbulence and we investigate two important issues: firstly the transport of supra-thermal particles in the excited microturbulence upstream of the shock and its consequences for the efficiency of the Fermi process; secondly, the preheating process of the incoming background electrons as they cross the shock precursor and experience relativistic oscillations in the electric field of the micro-turbulence.We emphasize the impor...

  11. Charged-Particle Motion in Electromagnetic Fields Having at Least One Ignorable Spatial Coordinate

    CERN Document Server

    Jones, F C; Baring, M G; Jones, Frank C.; Baring, Matthew G.

    1998-01-01

    We give a rigorous derivation of a theorem showing that charged particles in an arbitrary electromagnetic field with at least one ignorable spatial coordinate remain forever tied to a given magnetic-field line. Such a situation contrasts the significant motions normal to the magnetic field that are expected in most real three-dimensional systems. It is pointed out that, while the significance of the theorem has not been widely appreciated, it has important consequences for a number of problems and is of particular relevance for the acceleration of cosmic rays by shocks.

  12. Analysis of ultra-relativistic charged particle beam and stretched wire measurement interactions with cylindrically symmetric structures

    Energy Technology Data Exchange (ETDEWEB)

    Deibele, C. E. [Univ. of Wisconsin, Madison, WI (United States)

    1996-01-01

    The beam impedance and wakefield are quantities which describe the stability of charged particles in their trajectory within an accelerator. The stretched wire measurement technique is a method which estimates the beam impedance and wakefield. Definitions for the beam impedance, the wakefield, and the stretched wire measurement are presented. A pillbox resonator with circular beampipes is studied for its relatively simple profile and mode structure. Theoretical predictions and measurement data are presented for the interaction of various charged particle beams and center conductor geometries between the cavity and beampipe. Time domain predictions for the stretched wire measurement and wakefield are presented and are shown to be a linear interaction.

  13. Time-Dependent Stochastic Particle Acceleration in Astrophysical Plasmas: Exact Solutions Including Momentum-Dependent Escape

    CERN Document Server

    Becker, P A; Le, T

    2006-01-01

    Stochastic acceleration of charged particles due to interactions with magnetohydrodynamic (MHD) plasma waves is the dominant process leading to the formation of the high-energy electron and ion distributions in a variety of astrophysical systems. Collisions with the waves influence both the energization and the spatial transport of the particles, and therefore it is important to treat these two aspects of the problem in a self-consistent manner. We solve the representative Fokker-Planck equation to obtain a new, closed-form solution for the time-dependent Green's function describing the acceleration and escape of relativistic ions interacting with Alfven or fast-mode waves characterized by momentum diffusion coefficient $D(p)\\propto p^q$ and mean particle escape timescale $t_esc(p) \\propto p^{q-2}$, where $p$ is the particle momentum and $q$ is the power-law index of the MHD wave spectrum. In particular, we obtain solutions for the momentum distribution of the ions in the plasma and also for the momentum dist...

  14. Charge dependence of nano-particle growth in silane plasmas under UV irradiation

    Science.gov (United States)

    Seon, C. R.; Choe, W.; Chai, K. B.; Park, H. Y.; Park, S.

    2009-01-01

    The controlled generation of nano-particles has been an important issue for the nano-structure formation in processing plasmas. We observed that the particle growth under UV irradiation was enhanced due to electric charge reduction of the particles, suggesting that the variation of particle charges could be a control parameter for the particle growth. The particle growth variation by UV irradiation is well described by the particle coagulation model with time-dependent particle charges in consideration, where predator particles grow by adsorbing a few nanometer-sized proto-particles.

  15. Improved search for elementary particles with fractional electric charge

    Energy Technology Data Exchange (ETDEWEB)

    Mar, N.M.; Lee, E.R.; Fleming, G.R.; Casey, B.C.; Perl, M.L.; Garwin, E.L. [Stanford Linear Accelerator Center, Stanford, California 94309 (United States); Hendricks, C.D. [W. J. Schafer Associates, Livermore, California 94550 (United States); Lackner, K.S. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Shaw, G.L. [Department of Physics, University of California, Irvine, California 92717 (United States)

    1996-06-01

    We have devised and demonstrated the successful operation of a low-cost, high-mass throughput technique capable of performing bulk matter searches for fractionally charged particles based on an improved Millikan liquid drop method. The method uses a stroboscopic lamp and a charge coupled device video camera to image the trajectories of silicone oil drops falling through air in the presence of a vertical, alternating electric field. The images of the trajectories are computer processed in real time, the electric charge on a drop being measured with an rms error of 0.025 of an electron charge. This error is dominated by Brownian motion. In the first use of this method, we have looked at 5974941 drops and found no evidence for fractional charges in 1.07 mg of oil. With 95{percent} confidence, the concentration of isolated quarks with {plus_minus}1/3{ital e} or {plus_minus}2/3{ital e} in silicone oil is less than one per 2.14{times}10{sup 20} nucleons. {copyright} {ital 1996 The American Physical Society.}

  16. Improved search for elementary particles with fractional electric charge

    Science.gov (United States)

    Mar, Nancy M.; Lee, Eric R.; Fleming, George R.; Casey, Brendan C. K.; Perl, Martin L.; Garwin, Edward L.; Hendricks, Charles D.; Lackner, Klaus S.; Shaw, Gordon L.

    1996-06-01

    We have devised and demonstrated the successful operation of a low-cost, high-mass throughput technique capable of performing bulk matter searches for fractionally charged particles based on an improved Millikan liquid drop method. The method uses a stroboscopic lamp and a charge coupled device video camera to image the trajectories of silicone oil drops falling through air in the presence of a vertical, alternating electric field. The images of the trajectories are computer processed in real time, the electric charge on a drop being measured with an rms error of 0.025 of an electron charge. This error is dominated by Brownian motion. In the first use of this method, we have looked at 5 974 941 drops and found no evidence for fractional charges in 1.07 mg of oil. With 95% confidence, the concentration of isolated quarks with +/-1/3e or +/-2/3e in silicone oil is less than one per 2.14×1020 nucleons.

  17. Human fibrinogen adsorption on positively charged latex particles.

    Science.gov (United States)

    Zeliszewska, Paulina; Bratek-Skicki, Anna; Adamczyk, Zbigniew; Cieśla, Michał

    2014-09-23

    Fibrinogen (Fb) adsorption on positively charged latex particles (average diameter of 800 nm) was studied using the microelectrophoretic and the concentration depletion methods based on AFM imaging. Monolayers on latex were adsorbed from diluted bulk solutions at pH 7.4 and an ionic strength in the range of 10(-3) to 0.15 M where fibrinogen molecules exhibited an average negative charge. The electrophoretic mobility of the latex after controlled fibrinogen adsorption was systematically measured. A monotonic decrease in the electrophoretic mobility of fibrinogen-covered latex was observed for all ionic strengths. The results of these experiments were interpreted according to the three-dimensional electrokinetic model. It was also determined using the concentration depletion method that fibrinogen adsorption was irreversible and the maximum coverage was equal to 0.6 mg m(-2) for ionic strength 10(-3) M and 1.3 mg m(-2) for ionic strength 0.15 M. The increase of the maximum coverage was confirmed by theoretical modeling based on the random sequential adsorption approach. Paradoxically, the maximum coverage of fibrinogen on positively charged latex particles was more than two times lower than the maximum coverage obtained for negative latex particles (3.2 mg m(-2)) at pH 7.4 and ionic strength of 0.15 M. This was interpreted as a result of the side-on adsorption of fibrinogen molecules with their negatively charged core attached to the positively charged latex surface. The stability and acid base properties of fibrinogen monolayers on latex were also determined in pH cycling experiments where it was observed that there were no irreversible conformational changes in the fibrinogen monolayers. Additionally, the zeta potential of monolayers was more positive than the zeta potential of fibrinogen in the bulk, which proves a heterogeneous charge distribution. These experimental data reveal a new, side-on adsorption mechanism of fibrinogen on positively charged surfaces and

  18. Acceleration of particles in Janis-Newman-Winicour singularities

    CERN Document Server

    Patil, Mandar

    2011-01-01

    We examine here the acceleration of particles and high energy collisions in the the Janis-Newman- Winicour (JNW) spacetime, which is an extension of the Schwarzschild geometry when a massless scalar field is included. We show that while the center of mass energy of collisions of particles near the event horizon of a blackhole is not significantly larger than the rest mass of the interacting particles, in an analogous situation, it could be arbitrarily large in the JNWspacetime near the naked singularity. The high energy collisions are seen to be generic in the presence of a photon sphere in the JNW spacetime, whereas an extreme fine-tuning of the angular momentum of the colliding particles is required when the photon sphere is absent. The center of mass energy of collision near the singularity grows slowly for small and extremely large deviations from the Schwarzschild blackhole, but for intermediate strengths of the scalar field it rises moderately fast. As a possible and potentially interesting application,...

  19. Particle acceleration and transport in the solar atmosphere

    Science.gov (United States)

    Kontar, Eduard

    2016-07-01

    During periods of sporadic flare activity, the Sun releases energy stored in the magnetic field into the plasma of the solar atmosphere. This is an extremely efficient process, with a large fraction of the magnetic energy going into plasma particles. The solar flares are accompanied by prompt electromagnetic emission virtually over the entire electromagnetic spectrum from gamma-rays down to radio frequencies. The Sun, through its activity, also plays a driving role in the Sun-Earth system that substantially influences geophysical space. Solar flare energetic particles from the Sun are detected in interplanetary space by in-situ measurements making them a vital component of the single Sun-Earth system. Although a qualitative picture is generally agreed upon, many processes solar flare processes are poorly understood. Specifically, the processes of acceleration and propagation of energetic particles interacting on various physical scales remain major challenges in solar physics and basic plasma physics. In the talk, I will review the current understanding of solar flare energetic particles focusing on recent observational progress, which became possible due to the numerous spacecraft and ground-based observations.

  20. Coherent Light induced in Optical Fiber by a Charged Particle

    Science.gov (United States)

    Artru, Xavier; Ray, Cédric

    2016-07-01

    Coherent light production in an optical fiber by a charged particle (named PIGL, for particle-induced guided, light) is reviewed. From the microscopic point of view, light is emitted by transient electric dipoles induced in the fiber medium by the Coulomb field of the particle. The phenomenon can also considered as the capture of virtual photons of the particle field by the fiber. Two types of captures are distinguished. Type-I takes place in a uniform part of the fiber; then the photon keeps its longitudinal momentum pz . Type-II takes place near an end or in a non-uniform part of the fiber; then pz is not conserved. Type-I PIGL is not affected by background lights external to the fiber. At grazing incidence it becomes nearly monochromatic. Its circular polarization depends on the angular momentum of the particle about the fiber and on the relative velocity between the particle and the guided wave. A general formula for the yield of Type-II radiation, based on the reciprocity theorem, is proposed. This radiation can be assisted by metallic objects stuck to the fiber, via plasmon excitation. A periodic structure leads to a guided Smith-Purcell radiation. Applications of PIGL in beam diagnostics are considered.

  1. Particle Acceleration and Plasma Heating in the Chromosphere

    Science.gov (United States)

    Zaitsev, V. V.; Stepanov, A. V.

    2015-12-01

    We propose a new mechanism of electron acceleration and plasma heating in the solar chromosphere, based on the magnetic Rayleigh-Taylor instability. The instability develops at the chromospheric footpoints of a flare loop and deforms the local magnetic field. As a result, the electric current in the loop varies, and a resulting inductive electric field appears. A pulse of the induced electric field, together with the pulse of the electric current, propagates along the loop with the Alfvén velocity and begins to accelerate electrons up to an energy of about 1 MeV. Accelerated particles are thermalized in the dense layers of the chromosphere with the plasma density n ≈10^{14} - 10^{15} cm^{-3}, heating them to a temperature of about several million degrees. Joule dissipation of the electric current pulse heats the chromosphere at heights that correspond to densities n ≤10^{11} - 10^{13} cm^{-3}. Observations with the New Solar Telescope at Big Bear Solar Observatory indicate that chromospheric footpoints of coronal loops might be heated to coronal temperatures and that hot plasma might be injected upwards, which brightens ultra-fine loops from the photosphere to the base of the corona. Thereby, recent observations of the Sun and the model we propose stimulate a déjà vu - they are reminiscent of the concept of the chromospheric flare.

  2. Particle Acceleration in Relativistic Electron-Ion Outlfows

    CERN Document Server

    Lloyd-Ronning, Nicole M

    2016-01-01

    We use the Los Alamos VPIC code to investigate particle acceleration in relativistic, unmagnetized, collisionless electron-ion plasmas. We run our simulations both with a realistic proton-to-electron mass ratio m_p/m_e = 1836, as well as commonly employed mass ratios of m_p/m_e =100 and 25, and show that results differ among the different cases. In particular, for the physically accurate mass ratio, electron acceleration occurs efficiently in a narrow region of a few hundred inertial lengths near the flow front, producing a power law dN/dgamma ~ gamma^(-p) with p ~ -2 developing over a few decades in energy, while acceleration is weak in the region far downstream. We find 20%, 10%, and 0.2% of the total energy given to the electrons for mass ratios of 25, 100, and 1836 respectively at a time of 2500 (w_p)^-1. Our simulations also show significant magnetic field generation just ahead of and behind the the flow front, with about 1% of the total energy going into the magnetic field for a mass ratio of 25 and 100...

  3. Induced radioactivity in and around high-energy particle accelerators.

    Science.gov (United States)

    Vincke, Helmut; Theis, Chris; Roesler, Stefan

    2011-07-01

    Particle accelerators and their surroundings are locations of residual radioactivity production that is induced by the interaction of high-energy particles with matter. This paper gives an overview of the principles of activation caused at proton accelerators, which are the main machines operated at Conseil Européen pour la Recherche Nucléaire. It describes the parameters defining radio-nuclide production caused by beam losses. The second part of the paper concentrates on the analytic calculation of activation and the Monte Carlo approach as it is implemented in the FLUKA code. Techniques used to obtain, on the one hand, estimates of radioactivity in Becquerel and, on the other hand, residual dose rates caused by the activated material are discussed. The last part of the paper focuses on experiments that allow for benchmarking FLUKA activation calculations and on simulations used to predict activation in and around high-energy proton machines. In that respect, the paper addresses the residual dose rate that will be induced by proton-proton collisions at an energy of two times 7 TeV in and around the Compact Muon Solenoid (CMS) detector. Besides activation of solid materials, the air activation expected in the CMS cavern caused by this beam operation is also discussed.

  4. Aging of organic materials around high-energy particle accelerators

    Science.gov (United States)

    Tavlet, Marc

    1997-08-01

    Around particle accelerators used for fundamental research on the basic structure of matter, materials and components are exposed to ionizing radiation caused by beam losses in the proton machines and by synchrotron radiation in the lepton machines. Furthermore, with the high-energy and high-intensity collisions produced from future colliders, radiation damage is also to be expected in particle-physics detectors. Therefore, for a safe and reliable operation, the radiation aging of most of the components has to be assessed prior to their selection. An extensive radiation-damage test program has been carried out at CERN for decades on a routine basis and many results have been published. The tests have mainly concentrated on magnet-coil insulations and cable-insulating materials; they are carried out in accordance with the IEC 544 standard which defines the mechanical tests to be performed and the methods of degradation evaluation. The mechanical tests are also used to assess the degradation of composite structural materials. Moreover, electrical properties of high-voltage insulations and optical properties of organic scintillators and wave guides have also been studied. Our long-term experience has pointed out many parameters to be taken into account for the estimate of the lifetime of components in the radiation environment of our accelerators. One of the main parameters is the dose-rate effect, but the influence of other parameters has sometimes to be taken into account.

  5. Particle acceleration in ultra-relativistic parallel shock waves

    CERN Document Server

    Meli, A

    2003-01-01

    Monte-Carlo computations for highly relativistic parallel shock particle acceleration are presented for upstream flow gamma factors, $\\Gamma=(1-V_{1}^{2}/c^{2})^{-0.5}$ with values between 5 and $10^{3}$. The results show that the spectral shape at the shock depends on whether or not the particle scattering is small angle with $\\delta \\theta 2r_{g} \\Gamma^{2}$ where $\\lambda$ is the scattering mean free path along the field line and $r_{g}$ the gyroradius, these quantities being measured in the plasma flow frame. The large angle scattering case exhibits distinctive structure superimposed on the basic power-law spectrum, largely absent in the pitch angle case. Also, both cases yield an acceleration rate faster than estimated by the conventional, non-relativistic expression, $t_{acc}=[c/(V_{1}-V_{2})] [\\lambda_{1}/V_{1}+\\lambda_{2}/V_{2}]$ where '1' and '2' refer to upstream and downstream and $\\lambda$ is the mean free path. A $\\Gamma^{2}$ energy enhancement factor in the first shock crossing cycle and a sign...

  6. On the coupling of fields and particles in accelerator and plasma physics

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2016-10-15

    In accelerator and plasma physics it is generally accepted that there is no need to solve the dynamical equations for particles motion in manifestly covariant form, that is by using the coordinate-independent proper time to parameterize particle world-lines in space-time. In other words, in order to describe the dynamical processes in the laboratory frame there is no need to use the laws of relativistic kinematics. It is sufficient to take into account the relativistic dependence of the particles momentum on the velocity in the second Newton's law. Therefore, the coupling of fields and particles is based, on the one hand, on the use of result from particle dynamics treated according to Newton's laws in terms of the relativistic three-momentum and, on the other hand, on the use of Maxwell's equations in standard form. In previous papers we argued that this is a misconception. The purpose of this paper is to describe in detail how to calculate the coupling between fields and particles in a correct way and how to develop a new algorithm for a particle tracking code in agreement with the use of Maxwell's equations in their standard form. Advanced textbooks on classical electrodynamics correctly tell us that Maxwell's equations in standard form in the laboratory frame and charged particles are coupled by introducing particles trajectories as projections of particles world-lines onto coordinates of the laboratory frame and by subsequently using the laboratory time to parameterize the trajectory curves. For the first time we showed a difference between conventional and covariant particle tracking results in the laboratory frame. This essential point has never received attention in the physical community. Only the solution of the dynamical equations in covariant form gives the correct coupling between field equations in standard form and particles trajectories in the laboratory frame. We conclude that previous theoretical and simulation results in

  7. Charged particle diffusion and acceleration in Saturn's radiation belts

    Science.gov (United States)

    Mckibben, R. B.; Simpson, J. A.

    1980-01-01

    In the present paper, an attempt is made to determine, from the observed intensity profiles for protons and electrons in the region of L smaller than 4, whether population of Saturn's innermost trapped radiation zones from an external source is possible. It is found that if diffusion proceeds in an episodic rather than a steady-state manner (long periods of quiescence interrupted by brief periods of rapid diffusion), the basic features of the observed phase space density profiles are qualitatively reproduced for both the trapped protons and electrons.

  8. Estimation of direct laser acceleration in laser wakefield accelerators using particle-in-cell simulations

    CERN Document Server

    Shaw, J L; Marsh, K A; Tsung, F S; Mori, W B; Joshi, C

    2015-01-01

    Many current laser wakefield acceleration (LWFA) experiments are carried out in a regime where the laser pulse length is on the order of or longer than the wake wavelength and where ionization injection is employed to inject electrons into the wake. In these experiments, the trapped electrons will co-propagate with the longitudinal wakefield and the transverse laser field. In this scenario, the electrons can gain a significant amount of energy from both the direct laser acceleration (DLA) mechanism as well as the usual LWFA mechanism. Particle-in-cell (PIC) codes are frequently used to discern the relative contribution of these two mechanisms. However, if the longitudinal resolution used in the PIC simulations is inadequate, it can produce numerical heating that can overestimate the transverse motion, which is important in determining the energy gain due to DLA. We have therefore carried out a systematic study of this LWFA regime by varying the longitudinal resolution of PIC simulations from the standard, bes...

  9. Theory of intense beams of charged particles optics of charged particle analyzers

    CERN Document Server

    Hawkes, Peter W

    2011-01-01

    Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains. * Contributions from leading international scholars and industry experts * Discusses hot topic areas and pr

  10. Far field acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

  11. Dosimetry of charged and neutral particles onboard a stratospheric balloon

    Science.gov (United States)

    Dönsdorf, Esther Miriam; Burmeister, Soenke; Heber, Bernd; Benton, Eric; Berger, Thomas

    The interaction of the primary galactic cosmic rays with constituents of the atmosphere leads to a complex secondary radiation field at high altitudes. Of special interest for aviation and thereby also for radiation protection is the height up to 30 km where the radiation field consists of charged and neutral particles. For the determination of the dose rates up to this altitude in the Earth's atmosphere a stratopheric balloon flight will be performed in central Oklahoma which has a cutoff rigidity of about 4 GV. Onboard there will be two different active radiation detector systems to measure the dose of charged and neutral particles in the stratosphere. The first one is a silicon telescope which consists of two 2 cm2 silicon PIN-photodiodes used as semiconductor detectors. This instrument will mainly be used to measure the charged component of the radiation field due to the fact that the silicon detectors have a rather low efficiency for the detection of neutrons and gammas with energies higher than 60 keV. The second instrument is a so called phoswich detector. It is composed of two dissimilar scintillators optically coupled to each other and to a common photomultiplier tube. For this experimental setup a combination of a fast plastic scintillator BC412 and a slow inorganic scintillator CsI(Na) is used. The pulses from the two scintillators will be separated by applying pulse shape analysis. These two different scintillator materials have been chosen because BC412 is hydrogen rich and thus the cross section for fast neutrons is relatively high and CsI(Na) has a high cross section for gamma radiation. The objective of the phoswich detector is to distinguish between gammas and neutrons but it is also possible to measure charged particles with this setup. The aim of the balloon flight is to determine the dose measured with these two different instruments and in particular to differentiate between the dose induced by charged particles and by the different neutral

  12. Charge cluster distribution in nanosites traversed by a single ionizing particle An experimental approach

    Science.gov (United States)

    Pszona, S.; Bantsar, A.; Kula, J.

    2008-11-01

    A method for modeling charge cluster formation by a single ionizing particle in nanoelectronic structures of few nanometres size is presented. The method is based on experimental modeling of charge formation in the equivalent gaseous nanosites irradiated by single charged particles and the subsequent scaling procedure to a needed medium. Propane irradiated by alpha particles is presented as an example.

  13. Origin of Nonthermal Emission from the Fermi Bubbles and Mechanisms of Particle Acceleration There

    CERN Document Server

    Dogiel, V A; Chernyshov, D O; Ko, C -M

    2013-01-01

    We analyse processes of particle acceleration in the Fermi Bubbles. The goal of our investigations is to obtain restrictions for acceleration mechanisms. Our analysis of the three processes: acceleration from background plasma, re-acceleration of relativistic electrons emitted by supernova remnants, and acceleration by shocks generated by processes of star tidal disruption in the Galactic Center, showed that the model of multi-shock acceleration does not have serious objections at present and therefore seems us more attractive than others.

  14. Radiation reaction on a classical charged particle: a modified form of the equation of motion.

    Science.gov (United States)

    Alcaine, Guillermo García; Llanes-Estrada, Felipe J

    2013-09-01

    We present and numerically solve a modified form of the equation of motion for a charged particle under the influence of an external force, taking into account the radiation reaction. This covariant equation is integro-differential, as Dirac-Röhrlich's, but has several technical improvements. First, the equation has the form of Newton's second law, with acceleration isolated on the left hand side and the force depending only on positions and velocities: Thus, the equation is linear in the highest derivative. Second, the total four-force is by construction perpendicular to the four-velocity. Third, if the external force vanishes for all future times, the total force and the acceleration automatically vanish at the present time. We show the advantages of this equation by solving it numerically for several examples of external force.

  15. Charge Acceleration and Field-Lines Curvature: A Fundamental Symmetry and Consequent Asymmetries

    CERN Document Server

    Elitzur, Avshalom C; Beniamini, Paz

    2012-01-01

    When a charge accelerates, its field-lines curve in a typical pattern. This pattern resembles the curvature induced on the field-lines by a neighboring charge. Not only does the latter case involve a similar curvature, it moreover results in attraction/repulsion. This suggests a hitherto unnoticed causal symmetry: charge acceleration-field curvature. We prove quantitatively that these two phenomena are essentially one and the same. The field stores some of the charge's mass, yet it is extended in space, hence when the charge accelerates, inertia makes the field lag behind. The resulting stress in the field stores some of the charge's kinetic energy in the form of potential energy. The electrostatic interaction is the approximate mirror image of this process: The potential energy stored within the field turns into the charge's kinetic energy. This partial symmetry offers novel insights into two debated issues in electromagnetism. The question whether a charge radiates in a gravitational field receives a new tw...

  16. Single Particle Dynamics in a Quasi-Integrable Nonlinear Accelerator Lattice

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, Sergey A. [Chicago U.; Nagaitsev, Sergei [Fermilab; Valishev, Alexander [Fermilab

    2016-04-28

    Fermilab is constructing the Integrable Optics Test Accelerator (IOTA) as the centerpiece of the Accelerator R&D Program towards high-intensity circular machines. One of the factors limiting the beam intensity in present circular accelerators is collective instabilities, which can be suppressed by a spread of betatron frequencies (tunes) through the Landau damping mechanism or by an external damper, if the instability is slow enough. The spread is usually created by octupole magnets, which introduce the tune dependence on the amplitude and, in some cases, by a chromatic spread (tune dependence on particle's momentum). The introduction of octupoles usually lead to a resonant behavior and a reduction of the dynamic aperture. One of the goals of the IOTA research program is to achieve a high betatron tune spread, while retaining a large dynamic aperture using conventional octupole magnets in a special but realistic accelerator configuration. In this report, we present results of computer simulations of an electron beam in the IOTA by particle tracking and the Frequency Map Analysis. The results show that the ring's octupole magnets can be configured to provide a betatron tune shift of 0.08 (for particles at large amplitudes) with the dynamical aperture of over 20 beam sigma for a 150-MeV electron beam. The influence of the synchrotron motion, lattice errors, and magnet imperfections is insignificant for the parameters and levels of tolerances set by the design of the ring. The described octupole insert could be beneficial for suppression of space-charge induced instabilities in high intensity machines.

  17. The Stability of the Vacuum Polarization Surrounding a Charged Particle

    CERN Document Server

    Himpsel, F J

    2015-01-01

    The internal stability of the electron has been debated for a century at both the classical and the quantum level. Recently, a local force density balance was established for the 1s electron in the H atom, based on the energy-momentum tensor of the classical Dirac field. This methodology is now extended to quantum fields by considering the force densities acting on the vacuum polarization induced by a point charge. Such a model is applicable to any charged particle at large distances, since the only vestige of its internal structure is the electric Coulomb field together with the vacuum polarization induced by it. While the polarization charge density is attracted to the point charge, it is kept from collapsing by repulsive forces due to confinement and degeneracy. It is shown analytically that the corresponding force densities are balanced for every filled shell of mj states at a given angular momentum j. The force densities are then summed over all single-electron states in the Dirac sea and renormalized by...

  18. Particle Tracking in Circular Accelerators Using the Exact Hamiltonian in SixTrack

    CERN Document Server

    Fjellstrom, Mattias; Hansson, Johan

    2013-12-13

    Particle motion in accelerators is in general complex. Tracking codes are developed to simulate beam dynamics in accelerators. SixTrack is a long lived particle tracking code maintained at CERN, the European Organization for Nuclear Research. A particle accelerator consists of a large number of magnets and other electromagnetic devices that guide the particle through the accelerator. Each device defines its own equation of motion, which often cannot be solved exactly. For this purpose, a number of approximations are introduced in order to facilitate the solution and to speed up the computation. In a high-energy accelerator, the particle has small transverse momentum components. This is exploited in the small-angle approximation. In this approximation the equations of motion are expanded to a low order in the transverse momentum components. In low-energy particle accelerators, or in tracking with large momentum deviations, this approximation is invalid. The equations of motion of a particle passing through a f...

  19. Determination of Beam Intensity and Position in a Particle Accelerator

    CERN Document Server

    Kasprowicz, Grzegorz

    2010-01-01

    The Proton Synchrotron accelerator (PS), installed at CERN, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC). The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajec- tory and orbit measurement system of the PS dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam position monitors (BPMs) and an analogue signal processing chain to acquire the trajectory of one single particle bunch out of many, over two consecutive turns at a maximum rate of once every 5ms. The BPMs were in good condition, however the electronics was aging and ...

  20. ACCELERATORS: Matching by solenoids in space charge dominated LEBTs

    Science.gov (United States)

    Li, Jin-Hai; Tang, Jing-Yu; Ouyang, Hua-Fu

    2009-10-01

    The betatron matching of a rotationally asymmetric beam in space charge dominated low-energy beam transports (LEBTs) where solenoids are used for the transverse matching has been studied. For better understanding, the coupling elements of a beam matrix are interpreted in special forms that are products of a term defined by the Larmor rotation angle and another by the difference between the beam matrix elements in the two transverse planes. The coupling form originally derived from the rotationally symmetric field in solenoids still holds when taking into account the rotationally asymmetric space charge forces that are due to the unequal emittance in the two transverse planes. It is shown in this paper that when an LEBT mainly comprising solenoids transports a beam having unequal emittance in the two transverse planes and the linear space charge force is taken into account, the initial Twiss parameters can be modified to obtain the minimum and equal emittance at the LEBT exit. The TRACE3D calculations also prove the principle. However, when quadrupoles that are also rotationally asymmetric are involved in between solenoids, the coupling between the two transverse planes becomes more complicated and the emittance increase is usually unavoidable. A matching example using the CSNS (China Spallation Neutron Source) LEBT conditions is also presented.

  1. Moving Charged Particles in Lattice Boltzmann-Based Electrokinetics

    CERN Document Server

    Kuron, Michael; Schornbaum, Florian; Bauer, Martin; Godenschwager, Christian; Holm, Christian; de Graaf, Joost

    2016-01-01

    The motion of ionic solutes and charged particles under the influence of an electric field and the ensuing hydrodynamic flow of the underlying solvent is ubiquitous in aqueous colloidal suspensions. The physics of such systems is described by a coupled set of differential equations, along with boundary conditions, collectively referred to as the electrokinetic equations. Capuani et al. [J. Chem. Phys. 121, 973 (2004)] introduced a lattice-based method for solving this system of equations, which builds upon the lattice Boltzmann (LB) algorithm for the simulation of hydrodynamic flow and exploits computational locality. However, thus far, a description of how to incorporate moving boundary conditions, which are needed to simulate moving colloids, into the Capuani scheme has been lacking. In this paper, we detail how to introduce such moving boundaries, based on an analogue to the moving boundary method for the pure LB solver. The key ingredients in our method are mass and charge conservation for the solute spec...

  2. Charged Particle Multiplicity Analysis in MicroBooNE

    Science.gov (United States)

    Rafique, Aleena; MicroBooNE Experiment Collaboration

    2017-01-01

    MicroBooNE is a short baseline neutrino experiment that utilizes 89 ton active volume liquid argon Time Projection Chamber (TPC) situated on the Booster Neutrino Beamline at Fermilab. It is the first of three liquid argon TPC detectors planned for the Fermilab Short Baseline Neutrino program and will directly probe the source of the anomalous excess of electron-like events in MiniBooNE, while also measuring low-energy neutrino cross sections and providing important R&D for future detectors. In this talk, a study of charged particle multiplicity using neutrino charged-current inclusive events is presented. This analysis can be used to test models of neutrino-argon scattering, and it may be particularly sensitive to nuclear final state interaction effects. Kansas State University.

  3. Resonant cyclotron acceleration of particles by a time periodic singular flux tube

    CERN Document Server

    Asch, Joachim; Stovicek, Pavel

    2010-01-01

    We study the dynamics of a classical nonrelativistic charged particle moving on a punctured plane under the influence of a homogeneous magnetic field and driven by a periodically time-dependent singular flux tube through the hole. We observe an effect of resonance of the flux and cyclotron frequencies. The particle is accelerated to arbitrarily high energies even by a flux of small field strength which is not necessarily encircled by the cyclotron orbit; the cyclotron orbits blow up and the particle oscillates between the hole and infinity. We support this observation by an analytic study of an approximation for small amplitudes of the flux which is obtained with the aid of averaging methods. This way we derive asymptotic formulas that are afterwards shown to represent a good description of the accelerated motion even for fluxes which are not necessarily small. More precisely, we argue that the leading asymptotic terms may be regarded as approximate solutions of the original system in the asymptotic domain as...

  4. Load management strategy for Particle-In-Cell simulations in high energy particle acceleration

    Science.gov (United States)

    Beck, A.; Frederiksen, J. T.; Dérouillat, J.

    2016-09-01

    In the wake of the intense effort made for the experimental CILEX project, numerical simulation campaigns have been carried out in order to finalize the design of the facility and to identify optimal laser and plasma parameters. These simulations bring, of course, important insight into the fundamental physics at play. As a by-product, they also characterize the quality of our theoretical and numerical models. In this paper, we compare the results given by different codes and point out algorithmic limitations both in terms of physical accuracy and computational performances. These limitations are illustrated in the context of electron laser wakefield acceleration (LWFA). The main limitation we identify in state-of-the-art Particle-In-Cell (PIC) codes is computational load imbalance. We propose an innovative algorithm to deal with this specific issue as well as milestones towards a modern, accurate high-performance PIC code for high energy particle acceleration.

  5. Design of a plasma discharge circuit for particle wakefield acceleration

    CERN Document Server

    Anania, M P; Cianchi, A; Di Giovenale, D; Ferrario, M; Flora, F; Gallerano, G P; Ghigo, A; Marocchino, A; Massimo, F; Mostacci, A; Mezi, L; Musumeci, P; Serio, M; 10.1016/j.nima.2013.10.053

    2014-01-01

    Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV m^-1), enabling acceleration of electrons to GeV energy in few centimetres. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators; radiofrequency-based accelerators, in fact, are limited in the accelerating field (10-100 MV m^-1) requiring therefore kilometric distances to reach the GeV energies, but can provide very bright electron bunches. Combining high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of shor...

  6. Charged Particle Multiplicities in Deep Inelastic Scattering at HERA

    CERN Document Server

    Aïd, S; Andreev, V; Andrieu, B; Appuhn, R D; Babaev, A; Ban, Y; Baranov, P S; Barrelet, E; Barschke, R; Bartel, Wulfrin; Barth, Monique; Bassler, U; Beck, H P; Behrend, H J; Belousov, A; Berger, C; Bernardi, G; Bertrand-Coremans, G H; Besançon, M; Beyer, R; Biddulph, P; Bispham, P; Bizot, J C; Blobel, Volker; Borras, K; Botterweck, F; Boudry, V; Braemer, A; Braunschweig, W; Brisson, V; Bruel, P; Bruncko, Dusan; Brune, C R; Buchholz, R; Buniatian, A Yu; Burke, S; Burton, M; Bähr, J; Büngener, L; Bürger, J; Büsser, F W; Calvet, D; Campbell, A J; Carli, T; Charlet, M; Chechelnitskii, S; Chernyshov, V; Clarke, D; Clegg, A B; Clerbaux, B; Cocks, S P; Contreras, J G; Cormack, C; Coughlan, J A; Courau, A; Cousinou, M C; Cozzika, G; Criegee, L; Cussans, D G; Cvach, J; Dagoret, S; Dainton, J B; Dau, W D; Daum, K; David, M; Davis, C L; De Wolf, E A; Delcourt, B; Di Nezza, P; Dirkmann, M; Dixon, P; Dlugosz, W; Dollfus, C; Dowell, John D; Dreis, H B; Droutskoi, A; Duhm, H; Dünger, O; Ebert, J; Ebert, T R; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellison, R J; Elsen, E E; Erdmann, M; Erdmann, W; Evrard, E; Fahr, A B; Favart, L; Fedotov, A; Feeken, D; Felst, R; Feltesse, Joel; Ferencei, J; Ferrarotto, F; Flamm, K; Fleischer, M; Flieser, M; Flügge, G; Fomenko, A; Fominykh, B A; Formánek, J; Foster, J M; Franke, G; Fretwurst, E; Gabathuler, Erwin; Gabathuler, K; Gaede, F; Garvey, J; Gayler, J; Gebauer, M; Genzel, H; Gerhards, R; Glazov, A; Goerlach, U; Gogitidze, N; Goldberg, M; Goldner, D; Golec-Biernat, Krzysztof J; González-Pineiro, B; Gorelov, I V; Grab, C; Greenshaw, T J; Griffiths, R K; Grindhammer, G; Gruber, A; Gruber, C; Grässler, Herbert; Grässler, R; Görlich, L; Haack, J; Hadig, T; Haidt, Dieter; Hajduk, L; Hampel, M; Haynes, W J; Heinzelmann, G; Henderson, R C W; Henschel, H; Herynek, I; Hess, M F; Hewitt, K; Hildesheim, W; Hiller, K H; Hilton, C D; Hladky, J; Hoeger, K C; Hoffmann, D; Holtom, T; Hoppner, M; Horisberger, R P; Hudgson, V L; Hufnagel, H; Hütte, M; Ibbotson, M; Itterbeck, H; Jacholkowska, A; Jacobsson, C; Jaffré, M; Janoth, J; Jansen, T; Johnson, D P; Jung, H; Jönsson, L B; Kalmus, Peter I P; Kander, M; Kant, D; Kaschowitz, R; Kathage, U; Katzy, J M; Kaufmann, H H; Kaufmann, O; Kazarian, S; Kenyon, Ian Richard; Kermiche, S; Keuker, C; Kiesling, C; Klein, M; Kleinwort, C; Knies, G; Kolanski, H; Kole, F; Kolya, S D; Korbel, V; Korn, M; Kostka, P; Kotelnikov, S K; Krasny, M W; Krehbiel, H; Krämerkämper, T; Krücker, D; Kuhlen, M; Kurca, T; Kurzhofer, J; Köhler, T; Köhne, J H; Küster, H; Lacour, D; Laforge, B; Lander, R; Landon, M P J; Lange, W; Langenegger, U; Laporte, J F; Lebedev, A; Lehner, F; Levonian, S; Lindström, G; Lindstrøm, M; Link, J; Linsel, F; Lipinski, J; List, B; Lobo, G; Loch, P; Lomas, J W; Lubimov, V; Lüke, D; López, G C; Magnussen, N; Malinovskii, E I; Mani, S; Maracek, R; Marage, P; Marks, J; Marshall, R; Martens, J; Martin, G; Martin, R D; Martyn, H U; Martyniak, J; Mavroidis, A; Maxfield, S J; McMahon, S J; Mehta, A; Meier, K; Meyer, A; Meyer, H; Meyer, J; Meyer, P O; Migliori, A; Mikocki, S; Milstead, D; Moeck, J; Moreau, F; Morris, J V; Mroczko, E; Murín, P; Müller, G; Müller, K; Nagovitsin, V; Nahnhauer, R; Naroska, Beate; Naumann, T; Negri, I; Newman, P R; Newton, D; Neyret, D; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Niedzballa, C; Niggli, H; Nisius, R; Nowak, G; Noyes, G W; Nyberg-Werther, M; Oakden, M N; Oberlack, H; Olsson, J E; Ozerov, D; Palmen, P; Panaro, E; Panitch, A; Pascaud, C; Patel, G D; Pawletta, H; Peppel, E; Phillips, J P; Pieuchot, A; Pitzl, D; Pope, G; Prell, S; Pérez, E; Rabbertz, K; Reimer, P; Reinshagen, S; Rick, Hartmut; Riech, V; Riedlberger, J; Riepenhausen, F; Riess, S; Rizvi, E; Robertson, S M; Robmann, P; Roloff, H E; Roosen, R; Rosenbauer, K; Rostovtsev, A A; Rouse, F; Royon, C; Rusakov, S V; Rybicki, K; Rädel, G; Rüter, K; Sankey, D P C; Schacht, P; Schiek, S; Schleif, S; Schleper, P; Schmidt, D; Schmidt, G; Schröder, V; Schuhmann, E; Schwab, B; Schöning, A; Sefkow, F; Seidel, M; Sell, R; Semenov, A A; Shekelian, V I; Shevyakov, I; Shtarkov, L N; Siegmon, G; Siewert, U; Sirois, Y; Skillicorn, Ian O; Smirnov, P; Smith, J R; Solochenko, V; Soloviev, Yu V; Specka, A E; Spiekermann, J; Spielman, S; Spitzer, H; Squinabol, F; Starosta, R; Steenbock, M; Steffen, P; Steinberg, R; Steiner, H; Steinhart, J; Stella, B; Stellberger, A; Stier, J; Stiewe, J; Stolze, K; Straumann, U; Struczinski, W; Stösslein, U; Sutton, J P; Tapprogge, Stefan; Tasevsky, M; Theissen, J; Thiebaux, C; Thompson, G; Truöl, P; Tsipolitis, G; Turnau, J; Tutas, J; Uelkes, P; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Esch, P; Van Mechelen, P; Van den Plas, D; Vazdik, Ya A; Verrecchia, P; Villet, G; Wacker, K; Wagener, A; Wagener, M; Walther, A; Waugh, B; Weber, G; Weber, M; Wegener, D; Wegner, A; Wengler, T; Werner, M; West, L R; Wiesand, S; Wilksen, T; Willard, S; Winde, M; Winter, G G; Wittek, C; Wobisch, M; Wünsch, E; Zarbock, D; Zhang, Z; Zhokin, A S; Zini, P; Zomer, F; Zsembery, J; Zuber, K; Zur Nedden, M; Zácek, J; de Roeck, A; von Schlippe, W

    1996-01-01

    Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastic ep scattering have been measured over a large kinematical region. The evolution with $W$ and $Q^2$ of the multiplicity distribution and of the multiplicity moments in pseudorapidity domains of varying size is studied in the current fragmentation region of the hadronic centre-of-mass frame. The results are compared with data from fixed target lepton-nucleon interactions, $e^+e^-$ annihilations and hadron-hadron collisions as well as with expectations from QCD based parton models. Fits to the Negative Binomial and Lognormal distributions are presented.

  7. A technique to improve crystal channeling efficiency of charged particles

    CERN Document Server

    Tikhomirov, V V

    2007-01-01

    It is shown that a narrow plane cut near the crystal surface considerably increases the probability of capture into the stable channeling motion of positively charged particles entering a crystal at angles smaller than a quarter of the critical channeling angle with respect to the crystal planes. At smallest incidence angles the capture probability reaches 99 percent. A pair of crystals bent in orthogonal planes and provided with the cuts allows to reach a 99.9 percent efficiency of single-pass deflection of a proton beam with an ultra small divergence. Conditions necessary for efficient single-pass deflection of protons from the LHC beam halo are also discussed.

  8. KAERI charged particle cross section library for radioisotope production

    CERN Document Server

    Chang, J H; Kim, D H; Lee, Y O; Zhuang, Y X

    2001-01-01

    This report summarized information and figures describing the 'KAERI Charged Particle Cross Section Library for Radioisotope production' The library contains proton-, deutron-, He-3-, and alpha-induced monitor cross sections, and gamma- and positron-emitter production cross sections. Experimental data and evaluation methods are described, and the evaluated cross sections are compared with those of the IAEA, MENDL, and LA150. The library has cross sections and emission spectra suitable for the transport analysis in the design of radioisotope production system, and are available at http://atom.kaeri.re.kr/ in ENDF-6 format.

  9. Explicit K-symplectic algorithms for charged particle dynamics

    Science.gov (United States)

    He, Yang; Zhou, Zhaoqi; Sun, Yajuan; Liu, Jian; Qin, Hong

    2017-02-01

    We study the Lorentz force equation of charged particle dynamics by considering its K-symplectic structure. As the Hamiltonian of the system can be decomposed as four parts, we are able to construct the numerical methods that preserve the K-symplectic structure based on Hamiltonian splitting technique. The newly derived numerical methods are explicit, and are shown in numerical experiments to be stable over long-term simulation. The error convergency as well as the long term energy conservation of the numerical solutions is also analyzed by means of the Darboux transformation.

  10. Inclusive photoproduction of single charged particles at high p T

    Science.gov (United States)

    Apsimon, R. J.; Atkinson, M.; Baake, M.; Bagdasarian, L. S.; Barberis, D.; Brodbeck, T. J.; Brook, N.; Charity, T.; Clegg, A. B.; Coyle, P.; Danaher, S.; Danagulian, S.; Davenport, M.; Dickinson, B.; Diekmann, B.; Donnachie, A.; Doyle, A. T.; Eades, J.; Ellison, R. J.; Flower, P. S.; Foster, J. M.; Galbraith, W.; Galumian, P. I.; Gapp, C.; Gebert, F.; Hallewell, G.; Heinloth, K.; Henderson, R. C. W.; Hickman, M. T.; Hoeger, C.; Holzkamp, S.; Hughes-Jones, R. E.; Ibbotson, M.; Jakob, H. P.; Joseph, D.; Keemer, N. R.; Kingler, J.; Koersgen, G.; Kolya, S. D.; Lafferty, G. D.; McCann, H.; McClatchey, R.; McManus, C.; Mercer, D.; Morris, J. A. G.; Morris, J. V.; Newton, D.; O'Connor, A.; Oedingen, R.; Oganesian, A. G.; Ottewell, P. J.; Paterson, C. N.; Paul, E.; Reid, D.; Rotscheidt, H.; Sharp, P. H.; Soeldner-Rembold, S.; Thacker, N. A.; Thompson, L.; Thompson, R. J.; Voigtlaender-Tetzner, A.; Waterhouse, J.; Weigend, A. S.; Wilson, G. W.

    1989-03-01

    Single charged-particle inclusive cross sections for photon, pion and kaon beams on hydrogen at the CERN-SPS are presented as functions of p T and x F . Data cover the range 0.01.6 GeV/c for the photon-induced data. Using the hadron-induced data to estimate the hadronic behaviour of the photon, the difference distributions and ratios of cross sections are a measure of the contribution of the point-like photon interactions. The data are compared with QCD calculations and show broadly similar features.

  11. Nonlinear delta f Simulations of Collective Effects in Intense Charged Particle Beams

    CERN Document Server

    Hong Qi

    2003-01-01

    A nonlinear delta(f) particle simulation method based on the Vlasov-Maxwell equations has been recently developed to study collective processes in high-intensity beams, where space-charge and magnetic self-field effects play a critical role in determining the nonlinear beam dynamics. Implemented in the Beam Equilibrium, Stability and Transport (BEST) code [H. Qin, R.C. Davidson, and W.W. Lee, Physical Review -- Special Topics on Accelerator and Beams 3 (2000) 084401; 3 (2000) 109901.], the nonlinear delta(f) method provides a low-noise and self-consistent tool for simulating collective interactions and nonlinear dynamics of high-intensity beams in modern and next-generation accelerators and storage rings, such as the Spallation Neutron Source and heavy ion fusion drivers. A wide range of linear eigenmodes of high-intensity charged-particle beams can be systematically studied using the BEST code. Simulation results for the electron-proton two-stream instability in the Proton Storage Ring experiment [R. Macek, ...

  12. Cellular and molecular analysis of mutagenesis induced by charged particles of defined linear energy transfer

    Science.gov (United States)

    Zhu, L. X.; Waldren, C. A.; Vannias, D.; Hei, T. K.; Chatterjee, A. (Principal Investigator)

    1996-01-01

    Mutation induction by charged particles of defined linear energy transfer (LET) and gamma rays was scored using human-hamster hybrid AL cells. The LET values for charged particles accelerated at the Radiological Research Accelerator Facility ranged from 10 keV/microm protons to 150 keV/microm 4He ions. The induced mutant fractions at both the S1 and HGPRT loci were dependent on the dose and LET. In addition, for each dose examined, the mutant yield at the S1 locus was 30-60 fold higher than at the corresponding HGPRT locus. To determine whether the mutation spectrum was comparably dependent on dose and LET, independent S1- and HGPRT- mutants induced by 150 keV/microm 4He ions and gamma rays were isolated, and their DNA was analyzed by both Southern blotting and multiplex PCR methods. While the majority of radiation-induced mutants showed deletions of varying sizes, the relative percentage of large deletions was found to be related to both the dose and LET of the radiation examined. Using a mutation system that can detect multilocus changes, results of the present study show that radiation-induced chromosomal loss can be in the millions of base pairs.

  13. The effect of cooling on particle trajectories and acceleration in relativistic magnetic reconnection

    CERN Document Server

    Kagan, Daniel; Piran, Tsvi

    2016-01-01

    The maximum synchrotron burnoff limit of 160 MeV represents a fundamental limit to radiation resulting from electromagnetic particle acceleration in one-zone ideal plasmas. In magnetic reconnection, however, particle acceleration and radiation are decoupled because the electric field is larger than the magnetic field in the diffusion region. We carry out two-dimensional particle-in-cell simulations to determine the extent to which magnetic reconnection can produce synchrotron radiation above the burnoff limit. We use the test particle comparison (TPC) method to isolate the effects of cooling by comparing the trajectories and acceleration efficiencies of test particles incident on such a reconnection region with and without cooling them. We find that the cooled and uncooled particle trajectories are typically similar during acceleration in the reconnection region, and derive an effective limit on particle acceleration that is inversely proportional to the average magnetic field experienced by the particle duri...

  14. Feature-based Analysis of Plasma-based Particle Acceleration Data

    Energy Technology Data Exchange (ETDEWEB)

    Ruebel, Oliver; Geddes, Cameron G.R.; Chen, Min; Cormier-Michel, Estelle; Bethel, E. Wes

    2013-07-05

    Plasma-based particle accelerators can produce and sustain thousands of times stronger acceleration fields than conventional particle accelerators, providing a potential solution to the problem of the growing size and cost of conventional particle accelerators. To facilitate scientific knowledge discovery from the ever growing collections of accelerator simulation data generated by accelerator physicists to investigate next-generation plasma-based particle accelerator designs, we describe a novel approach for automatic detection and classification of particle beams and beam substructures due to temporal differences in the acceleration process, here called acceleration features. The automatic feature detection in combination with a novel visualization tool for fast, intuitive, query-based exploration of acceleration features enables an effective top-down data exploration process, starting from a high-level, feature-based view down to the level of individual particles. We describe the application of our analysis in practice to analyze simulations of single pulse and dual and triple colliding pulse accelerator designs, and to study the formation and evolution of particle beams, to compare substructures of a beam and to investigate transverse particle loss.

  15. Measuring Charged Particle Multiplicity with Early ATLAS Public Data

    CERN Document Server

    Üstün, Gözde; Bektaş, Erhan; Özcan, V Erkcan

    2016-01-01

    We study 100 images of early LHC collisions that were recorded by the ATLAS experiment and made public for outreach purposes, and extract the charged particle multiplicity as a function of momentum for proton-proton collisions at sqrt(s) = 7 TeV. As the collisions we study have already been pre-processed by the ATLAS Collaboration, the tracks are visible, but are available to the public only in the form of low-resolution bitmaps. We employ two separate image processing methods, one based on the industry-standard OpenCV library and C++, another based on self-developed algorithms in Python. We present the transverse momentum and azimuthal angle distributions of the particles obtained through both methods, in agreement with the literature.

  16. A Search for Charged Massive Stable Particles at D0

    Energy Technology Data Exchange (ETDEWEB)

    Eads, Michael Terry [Northern Illinois Univ., DeKalb, IL (United States)

    2005-08-01

    A search for charged massive stable particles has been performed with the D0 detector at the Fermilab Tevatron. The signature is two particles reconstructed as muons, but with speed and invariant mass inconsistent with beam-produced muons. No excess of events is observed and limits are set on the production cross-section for pair-produced stable stau sleptons based on 390 pb-1 of data. Limits vary from 0.06 pb to 0.62 pb, depending on the stau mass, and are the strictest Tevatron limits to date. Mass limits are also set for stable charginos. The limits are 140 GeV/c2 for a higgsino-like chargino and 174 GeV/c2 for a gaugino-like chargino. These are currently the best limits to date for stable charginos.

  17. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2002-11-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  18. Search for Charged Massive Long-Lived Particles

    Energy Technology Data Exchange (ETDEWEB)

    Abazov V. M.; Abbott B.; Acharya B. S.; Adams M.; Adams T.; Alexeev G. D.; Alimena J.; Alkhazov G.; Alton A.; Alverson G.; Alves G. A.; Aoki M.; Askew A.; Asman B.; Atkins S.; Atramentov O.; Augsten K.; Avila C.; BackusMayes J.; Badaud F.; Bagby L.; Baldin B.; Bandurin D. V.; Banerjee S.; Barberis E.; Baringer P.; Barreto J.; Bartlett J. F.; Bassler U.; Bazterra V.; Bean A.; Begalli M.; Belanger-Champagne C.; Bellantoni L.; Beri S. B.; Bernardi G.; Bernhard R.; Bertram I.; Besancon M.; Beuselinck R.; Bezzubov V. A.; Bhat P. C.; Bhatnagar V.; Blazey G.; Blessing S.; Bloom K.; Boehnlein A.; Boline D.; Boos E. E.; Borissov G.; Bose T.; Brandt A.; Brandt O.; Brock R.; Brooijmans G.; Bross A.; Brown D.; Brown J.; Bu X. B.; Buehler M.; Buescher V.; Bunichev V.; Burdin S.; Burnett T. H.; Buszello C. P.; Calpas B.; Camacho-Perez E.; Carrasco-Lizarraga M. A.; Casey B. C. K.; Castilla-Valdez H.; Chakrabarti S.; Chakraborty D.; Chan K. M.; Chandra A.; Chapon E.; Chen G.; Chevalier-Thery S.; Cho D. K.; Cho S. W.; Choi S.; Choudhary B.; Cihangir S.; Claes D.; Clutter J.; Cooke M.; Cooper W. E.; Corcoran M.; Couderc F.; Cousinou M. -C.; Croc A.; Cutts D.; Das A.; Davies G.; De K.; de Jong S. J.; De la Cruz-Burelo E.; Deliot F.; Demina R.; Denisov D.; Denisov S. P.; Desai S.; Deterre C.; DeVaughan K.; Diehl H. T.; Diesburg M.; Ding P. F.; Dominguez A.; Dorland T.; Dubey A.; Dudko L. V.; Duggan D.; Duperrin A.; Dutt S.; Dyshkant A.; Eads M.; Edmunds D.; Ellison J.; Elvira V. D.; Enari Y.; Evans H.; Evdokimov A.; Evdokimov V. N.; Facini G.; Ferbel T.; Fiedler F.; Filthaut F.; Fisher W.; Fisk H. E.; Fortner M.; Fox H.; Fuess S.; Garcia-Bellido A.; Garcia-Guerra G. A.; Gavrilov V.; Gay P.; Geng W.; Gerbaudo D.; Gerber C. E.; Gershtein Y.; Ginther G.; Golovanov G.; Goussiou A.; Grannis P. D.; Greder S.; Greenlee H.; Greenwood Z. D.; Gregores E. M.; Grenier G.; Gris Ph.; Grivaz J. -F.; Grohsjean A.; Gruenendahl S.; Gruenewald M. W.; Guillemin T.; Gutierrez G.; Gutierrez P.; Haas A.; Hagopian S.; Haley J.; Han L.; Harder K.; Harel A.; Hauptman J. M.; Hays J.; Head T.; Hebbeker T.; Hedin D.; Hegab H.; Heinson A. P.; Heintz U.; Hensel C.; Heredia-De La Cruz I.; Herner K.; Hesketh G.; Hildreth M. D.; Hirosky R.; Hoang T.; Hobbs J. D.; Hoeneisen B.; Hohlfeld M.; Hubacek Z.; Hynek V.; Iashvili I.; Ilchenko Y.; Illingworth R.; Ito A. S.; Jabeen S.; Jaffre M.; Jamin D.; Jayasinghe A.; Jesik R.; Johns K.; Johnson M.; Jonckheere A.; Jonsson P.; Joshi J.; Jung A. W.; Juste A.; Kaadze K.; Kajfasz E.; Karmanov D.; Kasper P. A.; Katsanos I.; Kehoe R.; Kermiche S.; Khalatyan N.; Khanov A.; Kharchilava A.; Kharzheev Y. N.; Kohli J. M.; Kozelov A. V.; Kraus J.; Kulikov S.; Kumar A.; Kupco A.; Kurca T.; Kuzmin V. A.; Kvita J.; Lammers S.; Landsberg G.; Lebrun P.; Lee H. S.; Lee S. W.; Lee W. M.; Lellouch J.; Li L.; Li Q. Z.; Lietti S. M.; Lim J. K.; Lincoln D.; Linnemann J.; Lipaev V. V.; Lipton R.; Liu Y.; Lobodenko A.; Lokajicek M.; de Sa R. Lopes; Lubatti H. J.; Luna-Garcia R.; Lyon A. L.; Maciel A. K. A.; Mackin D.; Madar R.; Magana-Villalba R.; Malik S.; Malyshev V. L.; Maravin Y.; Martinez-Ortega J.; McCarthy R.; McGivern C. L.; Meijer M. M.; et al.

    2012-03-21

    We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb{sup -1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron p{bar p} collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss (dE/dx) inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and Higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.

  19. Black hole lightning due to particle acceleration at subhorizon scales

    CERN Document Server

    Aleksić, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Wilhelmi, E de Oña; Mendez, C Delgado; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Godinović, N; Muñoz, A González; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-01-01

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry, but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here, we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC telescopes revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20\\% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.

  20. The Mysterious Universe - Exploring Our World with Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brau, James E [University of Oregon

    2010-11-23

    The universe is dark and mysterious, more so than even Einstein imagined. While modern science has established deep understanding of ordinary matter, unidentified elements ("Dark Matter" and "Dark Energy") dominate the structure of the universe, its behavior and its destiny. What are these curious elements? We are now working on answers to these and other challenging questions posed by the universe with experiments at particle accelerators on Earth. Results of this research may revolutionize our view of nature as dramatically as the advances of Einstein and other quantum pioneers one hundred years ago. Professor Brau will explain for the general audience the mysteries, introduce facilities which explore them experimentally and discuss our current understanding of the underlying science. The presentation is at an introductory level, appropriate for anyone interested in physics and astronomy.

  1. Particle acceleration by stimulated emission of radiation in cylindrical waveguide

    Institute of Scientific and Technical Information of China (English)

    TIAN Xiu-Fang; WU Cong-Feng; JIA Qi-Ka

    2015-01-01

    In particle acceleration by stimulated emission of radiation (PASER),efficient interaction occurs when a train of micro-bunches has periodicity identical to the resonance frequency of the medium.Previous theoretical calculations based on the simplified model have only considered the energy exchange in the boundless condition.Under experimental conditions,however,the gas active medium must be guided by the metal waveguide.In this paper,we have developed a model of the energy exchange between a train of micro-bunches and a gas mixture active medium in a waveguide boundary for the first time,based on the theory of electromagnetic fields,and made detailed analysis and calculations with MathCAD.The results show that energy density can be optimized to a certain value to get the maximum energy exchange.

  2. Particle acceleration in sub-cycle optical cells

    CERN Document Server

    Terranova, F

    2014-01-01

    A single laser pulse with spot size smaller than half its wavelength ($w_0 < \\lambda/2$) can provide a net energy gain to ultra-relativistic particles. In this paper, we discuss the properties of an optical cell consisting of $N$ sub-cycle pulses that propagate in the direction perpendicular to the electron motion. We show that the energy gain produced by the cell is proportional to $N$ and it is sizable even for $\\mathcal{O}(1\\mathrm{ TW})$ pulses. The optical cell acts as a defocusing lens with chromatic aberration and can be treated as a linear component in conventional accelerators if the transverse size of the beam is of the order of $\\lambda$.

  3. Charging and coagulation of radioactive and nonradioactive particles in the atmosphere

    Directory of Open Access Journals (Sweden)

    Y.-H. Kim

    2015-09-01

    Full Text Available Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual effects of charging and coagulation on the microphysical evolution of atmospheric particles such as radioactive particles. The first approach employs ion balance, charge balance, and a bivariate population balance model (PBM to comprehensively calculate both charge accumulation and coagulation rates of particles. The second approach involves a much simpler description of charging, and uses a monovariate PBM and subsequent effects of charge on particle coagulation. The third approach is further simplified assuming that particles instantaneously reach their steady-state charge distributions. It is found that compared to the other two approaches, the first approach can accurately predict time-dependent changes in the size and charge distributions of particles over a wide size range covering from the free molecule to continuum regimes. The other two approaches can reliably predict both charge accumulation and coagulation rates for particles larger than about 40 nm and atmospherically relevant conditions. These approaches are applied to investigate coagulation kinetics of particles accumulating charge in a radioactive neutralizer, the urban atmosphere, and a radioactive plume. Limitations of the approaches are discussed.

  4. Charged particle tracking through electrostatic wire meshes using the finite element method

    Science.gov (United States)

    Devlin, L. J.; Karamyshev, O.; Welsch, C. P.

    2016-06-01

    Wire meshes are used across many disciplines to accelerate and focus charged particles, however, analytical solutions are non-exact and few codes exist which simulate the exact fields around a mesh with physical sizes. A tracking code based in Matlab-Simulink using field maps generated using finite element software has been developed which tracks electrons or ions through electrostatic wire meshes. The fields around such a geometry are presented as an analytical expression using several basic assumptions, however, it is apparent that computational calculations are required to obtain realistic values of electric potential and fields, particularly when multiple wire meshes are deployed. The tracking code is flexible in that any quantitatively describable particle distribution can be used for both electrons and ions as well as other benefits such as ease of export to other programs for analysis. The code is made freely available and physical examples are highlighted where this code could be beneficial for different applications.

  5. Measurement of charged particle production from 450 GeV/c protons on beryllium

    CERN Document Server

    Ambrosini, G; Bernier, K; Biino, C; Bonesini, M; Bonivento, W; Borer, K; Brooijmans, G; Catanesi, M G; Collazuol, G; Daniels, D C; Dittus, F B; Elsener, K; Godley, A; Grant, A; Grégoire, G; Guglielmi, A M; Kabana, S; Kabana, R; Klingenberg, R; Lehmann, G; Lindén, T; Linssen, Lucie; Marchionni, A; Mishra, S R; Moffitt, L; Moser, U; Palladino, Vittorio; Pietropaolo, F; Pretzl, Klaus P; Pullia, Antonio; Radicioni, E; Ragazzi, S; Stachel, J; Sergiampietri, F; Soler, F J P; Stoffel, F; Tabarelli de Fatis, T; Terranova, F; Tovey, Stuart N; Tsesmelis, E; Weber, M

    1999-01-01

    This paper presents the results on charged particle yields and production ratios as measured by the NA56/SPY experiment for 450 GeV/c proton interactions on beryllium targets. The data cover a secondary momentum range from 7 GeV/c to 135 GeV/c and $p_T$ values up to 600~MeV/c. An experimental accuracy on the measured yields in the range from $5 \\%$ to $10 \\%$, depending on the beam momentum, and around $3 \\%$ for the particle production ratios has been achieved. These measurements are relevant for a precise evaluation of fluxes and composition of neutrino beams at accelerators. Results on the target thickness and shape dependence are also reported. Inclusive invariant cross sections in the forward direction have been derived. %An experimental accuracy of about 3\\% has been achieved on the measurements %of the $K/\\pi$ production ratios. These results will greatly reduce %the uncertainty on the estimation of the $\

  6. Charged particle velocity map image reconstruction with one-dimensional projections of spherical functions

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Thomas; Liu Yuzhu; Knopp, Gregor; Hemberger, Patrick; Bodi, Andras; Radi, Peter; Sych, Yaroslav [Molecular Dynamics Group, Paul Scherrer Institut, 5232 Villigen (Switzerland)

    2013-03-15

    Velocity map imaging (VMI) is used in mass spectrometry and in angle resolved photo-electron spectroscopy to determine the lateral momentum distributions of charged particles accelerated towards a detector. VM-images are composed of projected Newton spheres with a common centre. The 2D images are usually evaluated by a decomposition into base vectors each representing the 2D projection of a set of particles starting from a centre with a specific velocity distribution. We propose to evaluate 1D projections of VM-images in terms of 1D projections of spherical functions, instead. The proposed evaluation algorithm shows that all distribution information can be retrieved from an adequately chosen set of 1D projections, alleviating the numerical effort for the interpretation of VM-images considerably. The obtained results produce directly the coefficients of the involved spherical functions, making the reconstruction of sliced Newton spheres obsolete.

  7. SELF-CONSISTENT LANGEVIN SIMULATION OF COULOMB COLLISIONS IN CHARGED-PARTICLE BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    J. QIANG; R. RYNE; S. HABIB

    2000-05-01

    In many plasma physics and charged-particle beam dynamics problems, Coulomb collisions are modeled by a Fokker-Planck equation. In order to incorporate these collisions, we present a three-dimensional parallel Langevin simulation method using a Particle-In-Cell (PIC) approach implemented on high-performance parallel computers. We perform, for the first time, a fully self-consistent simulation, in which the friction and diffusion coefficients are computed from first principles. We employ a two-dimensional domain decomposition approach within a message passing programming paradigm along with dynamic load balancing. Object oriented programming is used to encapsulate details of the communication syntax as well as to enhance reusability and extensibility. Performance tests on the SGI Origin 2000 and the Cray T3E-900 have demonstrated good scalability. Work is in progress to apply our technique to intrabeam scattering in accelerators.

  8. Charged particle motion near a linear magnetic null

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.; Cary, J.R.

    1983-08-01

    Charged particle motion near the null of a two-dimensional magnetic field is studied. Specifically, the magnetic field is given by the vector potential A = zpsi/sub 0/((y/a)/sup 2/+(epsilonx/a)/sup 2/), in which psi/sub 0/,a, and epsilon are constants with epsilon parameterizing the ellipticity of the flux surfaces. Conservation of canonical z momentum p/sub z/ reduces the number of nontrivial degrees of freedom to two. Scaling reduces the number of parameters in the system to two, epsilon and sigma (the sign of p/sub z/ ). Analytical and numerical methods are used to study the nature of orbits. The results are expressed conveniently in terms of epsilon and Qequivalent(2mE)/sup 1/2//p/sub z/. When epsilon is unity, the additional symmetry implies integrability. When epsilon is less than unity (the case epsilon>1 is trivially related) three regimes are found: (1) For Vertical BarQVertical Bar>>1 particle orbits are regular, (2) for epsilon/sup 3/2/< or approx. =Vertical BarQVertical Bar< or approx. =1 most particle orbits are stochastic, and (3) for Vertical BarQVertical Bar<particle orbits are regular, with the third invariant being the magnetic moment.

  9. Non-thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism

    Science.gov (United States)

    Guo, Xinyi; Sironi, Lorenzo; Narayan, Ramesh

    2014-10-01

    Electron acceleration to non-thermal energies in low Mach number (Ms Diffusive shock acceleration, also known as first-order Fermi acceleration, cannot be directly invoked to explain the acceleration of electrons. Rather, an additional mechanism is required to pre-accelerate the electrons from thermal to supra-thermal energies, so they can then participate in the Fermi process. In this work, we use two- and three-dimensional particle-in-cell plasma simulations to study electron acceleration in low Mach number shocks. We focus on the particle energy spectra and the acceleration mechanism in a reference run with Ms = 3 and a quasi-perpendicular pre-shock magnetic field. We find that about 15% of the electrons can be efficiently accelerated, forming a non-thermal power-law tail in the energy spectrum with a slope of p ~= 2.4. Initially, thermal electrons are energized at the shock front via shock drift acceleration (SDA). The accelerated electrons are then reflected back upstream where their interaction with the incoming flow generates magnetic waves. In turn, the waves scatter the electrons propagating upstream back toward the shock for further energization via SDA. In summary, the self-generated waves allow for repeated cycles of SDA, similarly to a sustained Fermi-like process. This mechanism offers a natural solution to the conflict between the bright radio synchrotron emission observed from the outskirts of galaxy clusters and the low electron acceleration efficiency usually expected in low Mach number shocks.

  10. Energy losses of positive and negative charged particles in electron gas

    Science.gov (United States)

    Diachenko, M. M.; Kholodov, R. I.

    2017-02-01

    A heavy charged particle propagation through electron gas has been studied using combination of non-relativistic quantum mechanics and the Green’s functions method. The energy loss of a charged particle has been found in the case of large transferred momentum taking into account the interference term in the expression for the rate. The dependence of the energy loss of a charged particles in electron gas with nonzero temperature on the sign of the charge has been obtained.

  11. Boron concentration measurement in biological tissues by charged particle spectrometry.

    Science.gov (United States)

    Bortolussi, S; Altieri, S

    2013-11-01

    Measurement of boron concentration in biological tissues is a fundamental aspect of boron neutron capture therapy, because the outcome of the therapy depends on the distribution of boron at a cellular level, besides on its overall concentration. This work describes a measurement technique based on the spectroscopy of the charged particles emitted in the reaction (10)B(n,α)(7)Li induced by thermal neutrons, allowing for a quantitative determination of the boron concentration in the different components that may be simultaneously present in a tissue sample, such as healthy cells, tumor cells and necrotic cells. Thin sections of tissue containing (10)B are cut at low temperatures and irradiated under vacuum in a thermal neutron field. The charged particles arising from the sample during the irradiation are collected by a thin silicon detector, and their spectrum is used to determine boron concentration through relatively easy calculations. The advantages and disadvantages of this technique are here described, and validation of the method using tissue standards with known boron concentrations is presented.

  12. Modeling of mesoscopic electrokinetic phenomena using charged dissipative particle dynamics

    Science.gov (United States)

    Deng, Mingge; Li, Zhen; Karniadakis, George

    2015-11-01

    In this work, we propose a charged dissipative particle dynamics (cDPD) model for investigation of mesoscopic electrokinetic phenomena. In particular, this particle-based method was designed to simulate micro- or nano- flows which governing by Poisson-Nernst-Planck (PNP) equation coupled with Navier-Stokes (NS) equation. For cDPD simulations of wall-bounded fluid systems, a methodology for imposing correct Dirichlet and Neumann boundary conditions for both PNP and NS equations is developed. To validate the present cDPD model and the corresponding boundary method, we perform cDPD simulations of electrostatic double layer (EDL) in the vicinity of a charged wall, and the results show good agreement with the mean-field theoretical solutions. The capacity density of a parallel plate capacitor in salt solution is also investigated with different salt concentration. Moreover, we utilize the proposed methodology to study the electroosmotic and electroosmotic/pressure-driven flow in a micro-channel. In the last, we simulate the dilute polyelectrolyte solution both in bulk and micro-channel, which show the flexibility and capability of this method in studying complex fluids. This work was sponsored by the Collaboratory on Mathematics for Mesoscopic Modeling of Materials (CM4) supported by DOE.

  13. Laser-accelerated proton beams as a new particle source

    Energy Technology Data Exchange (ETDEWEB)

    Nuernberg, Frank

    2010-11-15

    The framework of this thesis is the investigation of the generation of proton beams using high-intensity laser pulses. In this work, an experimental method to fully reconstruct laser-accelerated proton beam parameters, called radiochromic film imaging spectroscopy (RIS), was developed. Since the proton beam expansion is a plasma expansion with accompanying electrons, a low-energy electron spectrometer was developed, built and tested to study the electron distribution matching to the proton beam energy distribution. Two experiments were carried out at the VULCAN Petawatt laser with the aim of showing dynamic control and enhancement of proton acceleration using multiple or defocused laser pulses. Irradiating the target with a long pulse, low-intensity laser (10{sup 12} W/cm{sup 2}) prior to the main pulse ({proportional_to}ns), an optimum pre-plasma density scale length of 60 {mu}m is generated leading to an enhancement of the maximum proton energy ({proportional_to}25%), the proton flux (factor of 3) and the beam uniformity. Proton beams were generated more efficiently than previously by driving thinner target foils at a lower intensity over a large area. The optimum condition was a 2 {mu}m foil irradiated with an intensity of 10{sup 19} W/cm{sup 2} onto a 60 {mu}m spot. Laser to proton beam efficiencies of 7.8% have been achieved (2.2% before) - one of the highest conversion efficiencies ever achieved. In the frame of this work, two separate experiments at the TRIDENT laser system have shown that these laser-accelerated proton beams, with their high number of particles in a short pulse duration, are well-suited for creating isochorically heated matter in extreme conditions. Besides the manipulation of the proton beam parameters directly during the generation, the primary aim of this thesis was the capture, control and transport of laser-accelerated proton beams by a solenoidal magnetic field lense for further purpose. In a joint project proposal, the laser and

  14. Generation of annular, high-charge electron beams at the Argonne wakefield accelerator

    Science.gov (United States)

    Wisniewski, E. E.; Li, C.; Gai, W.; Power, J.

    2013-01-01

    We present and discuss the results from the experimental generation of high-charge annular(ring-shaped)electron beams at the Argonne Wakefield Accelerator (AWA). These beams were produced by using laser masks to project annular laser profiles of various inner and outer diameters onto the photocathode of an RF gun. The ring beam is accelerated to 15 MeV, then it is imaged by means of solenoid lenses. Transverse profiles are compared for different solenoid settings. Discussion includes a comparison with Parmela simulations, some applications of high-charge ring beams,and an outline of a planned extension of this study.

  15. Charge States of Solar Cosmic Rays and Constraints on Acceleration Times and Coronal Transport

    CERN Document Server

    Ruffolo, D

    1997-01-01

    We examine effects on the charge states of energetic ions associated with gradual solar flares due to shock heating and stripping at high ion velocities. Recent measurements of the mean charges of various elements after the flares of 1992 Oct 30 and 1992 Nov 2 allow one to place limits on the product of the electron density times the acceleration or coronal residence time. In particular, any residence in coronal loops must be for < 0.03 s, which rules out models of coronal transport in loops, such as the bird cage model. The results do not contradict models of shock acceleration of energetic ions from coronal plasma at various solar longitudes.

  16. Atmospheric new particle formation: real and apparent growth of neutral and charged particles

    Directory of Open Access Journals (Sweden)

    J. Leppä

    2011-01-01

    Full Text Available In this study we have provided simple analytical formulae to estimate the growth rate of a nucleation mode due to self-coagulation and the apparent growth rate due to coagulation scavenging by larger particles. These formulae were used on a set of simulations covering a wide range of atmospheric conditions. The modal growth rates were determined from the simulation results by summing the contribution of each process, by calculating the increase rate in the count mean diameter of the mode and by following the peak concentration of the mode. The results of these three methods were compared with each other and the means used to estimate the growth rate due to self-coagulation and coagulation scavenging were found to work quite well. We also investigated the role of charged particles and electric interactions in the growth of a nucleation mode. Charged particles were found to increase the growth rate due to both self-coagulation and coagulation scavenging by a factor of ~1.5 to 2. In case of increased condensation onto charged particles, the total condensational growth rate of a nucleation mode may increase significantly in the very early steps of the growth. The analytical formulae provided by this paper were designed to provide the growth rates due to different processes from aerosol dynamic simulations, but the same principles can be used to determine the growth rates from measurement data.

  17. Atmospheric new particle formation: real and apparent growth of neutral and charged particles

    Directory of Open Access Journals (Sweden)

    J. Leppä

    2011-05-01

    Full Text Available In this study we have provided simple analytical formulae to estimate the growth rate of a nucleation mode due to self-coagulation and the apparent growth rate due to coagulation scavenging by larger particles. These formulae were used on a set of simulations covering a wide range of atmospheric conditions. The modal growth rates were determined from the simulation results by summing the contribution of each process, by calculating the increase rate in the count mean diameter of the mode and by following the peak concentration of the mode. The results of these three methods were compared with each other and the means used to estimate the growth rate due to self-coagulation and coagulation scavenging were found to give accurate values. We also investigated the role of charged particles and electric interactions in the growth of a nucleation mode. Charged particles were found to increase the growth rate due to both self-coagulation and coagulation scavenging by a factor of ~1.5 to 2. In case of increased condensation onto charged particles, the total condensational growth rate of a nucleation mode may increase significantly in the very early steps of the growth. The analytical formulae provided by this paper were designed to provide the growth rates due to different processes from aerosol dynamic simulations, but the same principles can be used to determine the growth rates from measurement data.

  18. Response of Charged Particles in a Storage Ring to Gravitational Waves

    Institute of Scientific and Technical Information of China (English)

    DONG Dong; HUANG Chao-Guang

    2003-01-01

    The influence of gravitational waves on the charged particles in a storage ring is studied. It shows thatthe gravitational waves might be directly detected by monitoring the motion of charged particles in a storage ring. Theangular velocity of the charged particles is continually adjustable by changing the initial energy of particles and thestrength of the magnetic field. This feature is very useful for finding the gravitational waves with different frequencies.

  19. Response of Charged Particles in a Storage Ring to Gravitational Waves

    Institute of Scientific and Technical Information of China (English)

    DONGDong; HUANGChao-Guang

    2003-01-01

    The influence of gravitational waves on the charged particles in a storage ring is studied. It shows that the gravitational waves might be directly detected by monitoring the motion of charged particles in a storage ring. The angular velocity of the charged particles is continually adjustable by changing the initial energy of particles and the strength of the magnetic field. This feature is very useful for finding the gravitational waves with different frequencies.

  20. Charge-exchange limits on low-energy alpha-particle fluxes in solar flares

    CERN Document Server

    Hudson, Hugh; MacKinnon, Alec; Woods, Tom

    2014-01-01

    This paper reports on a search for flare emission via charge-exchange radiation in the wings of the Lyman-alpha line of He ii at 304 A, as originally suggested for hydrogen by Orrall and Zirker. Via this mechanism a primary alpha particle that penetrates into the neutral chromosphere can pick up an atomic electron and emit in the He ii bound-bound spectrum before it stops. The Extreme-ultraviolet Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) gives us our first chance to search for this effect systematically. The Orrall-Zirker mechanism has great importance for flare physics because of the essential roles that particle acceleration plays; this mechanism is one of the few proposed that would allow remote sensing of primary accelerated particles below a few MeV/nucleon. We study ten events in total, including the gamma-ray events SOL2010-06-12 (M2.0) and SOL2011-02-24 (M3.5) (the latter a limb flare), seven X-class flares, and one prominent M-class event that produced solar energetic...

  1. Radiation reaction on charged particles in three-dimensional motion in classical and quantum electrodynamics

    Science.gov (United States)

    Higuchi, Atsushi; Martin, Giles D. R.

    2006-01-01

    We extend our previous work [A. Higuchi and G. D. R. Martin, Found. Phys. 35, 1149 (2005)FNDPA40015-901810.1007/s10701-005-6405-0], which compared the predictions of quantum electrodynamics concerning radiation reaction with those of the Abraham-Lorentz-Dirac theory for a charged particle in linear motion. Specifically, we calculate the predictions for the change in position of a charged-scalar particle, moving in three-dimensional space, due to the effect of radiation reaction in the one-photon-emission process in quantum electrodynamics. The scalar particle is assumed to be accelerated for a finite period of time by a three-dimensional electromagnetic potential dependent only on one of the spacetime coordinates. We perform this calculation in the ℏ→0 limit and show that the change in position agrees with that obtained in classical electrodynamics with the Lorentz-Dirac force treated as a perturbation. We also show for a time-dependent but space-independent electromagnetic potential that the forward-scattering amplitude at order e2 does not contribute to the position change in the ℏ→0 limit after the mass renormalization is taken into account.

  2. Measuring Landau damping in Particle-in-Cell simulations using particles of different charge-weights

    Science.gov (United States)

    Ren, C.; Sarkar, A.; Cao, Y.-X.; Huang, M. C.; Li, J.

    2016-10-01

    We study whether putting more particles in ``region of interest (ROI)'' in phase space can efficiently increase Particle-in-Cell (PIC) simulation accuracy. We use Landau damping of a plasma wave as a figure of merit and set the ROI near the phase velocity of the wave. Improvement in Landau damping rate measurement is observed in 1D PIC simulations when employing more particles in the ROI but the effect is not monotonic. This is partly due to energy transfer from particles of large charge weights to those of smaller weights through the electric fields. Possible strategies to mitigate the energy transfer will also be discussed. This work is supported by the National Science Foundation under Grant No. PHY-1314734 and by the Department of Energy under Grant No. DE-SC0012316.

  3. Classical scattering of charged particles confined on an inhomogeneous helix

    CERN Document Server

    Zampetaki, A V; Krönke, S; Schmelcher, P

    2013-01-01

    We explore the effects arising due to the coupling of the center of mass and relative motion of two charged particles confined on an inhomogeneous helix with a locally modified radius. It is first proven that a separation of the center of mass and the relative motion is provided if and only if the confining manifold represents a homogeneous helix. In this case bound states of repulsively Coulomb interacting particles occur. For an inhomogeneous helix, the coupling of the center of mass and relative motion induces an energy transfer between the collective and relative motion, leading to dissociation of initially bound states in a scattering process. Due to the time reversal symmetry, a binding of the particles out of the scattering continuum is thus equally possible. We identify the regimes of dissociation for different initial conditions and provide an analysis of the underlying phase space via Poincar\\'e surfaces of section. Bound states inside the inhomogeneity as well as resonant states are identified.

  4. Charged Particle Motion in a Highly Ionized Plasma

    CERN Document Server

    Brown, L S; Singleton, R; Brown, Lowell S; Preston, Dean L; Singleton, Robert L

    2005-01-01

    A recently introduced method utilizing dimensional continuation is employed to compute the energy loss rate for a non-relativistic particle moving through a highly ionized plasma. No restriction is made on the charge, mass, or speed of this particle. It is, however, assumed that the plasma is not strongly coupled in the sense that the dimensionless plasma coupling parameter g=e^2\\kappa_D/ 4\\pi T is small, where \\kappa_D is the Debye wave number of the plasma. To leading and next-to-leading order in this coupling, dE/dx is of the generic form g^2 \\ln[C g^2]. The precise numerical coefficient out in front of the logarithm is well known. We compute the constant C under the logarithm exactly for arbitrary particle speeds. Our exact results differ from approximations given in the literature. The differences are in the range of 20% for cases relevant to inertial confinement fusion experiments. The same method is also employed to compute the rate of momentum loss for a projectile moving in a plasma, and the rate at ...

  5. Chaotic phenomena of charged particles in crystal lattices.

    Science.gov (United States)

    Desalvo, Agostino; Giannerini, Simone; Rosa, Rodolfo

    2006-06-01

    In this article, we have applied the methods of chaos theory to channeling phenomena of positive charged particles in crystal lattices. In particular, we studied the transition between two ordered types of motion; i.e., motion parallel to a crystal axis (axial channeling) and to a crystal plane (planar channeling), respectively. The transition between these two regimes turns out to occur through an angular range in which the particle motion is highly disordered and the region of phase space spanned by the particle is much larger than the one swept in the two ordered motions. We have evaluated the maximum Lyapunov exponent with the method put forward by Rosenstein et al. [Physica D 65, 117 (1993)] and by Kantz [Phys. Lett. A 185, 77 (1994)]. Moreover, we estimated the correlation dimension by using the Grassberger-Procaccia method. We found that at the transition the system exhibits a very complex behavior showing an exponential divergence of the trajectories corresponding to a positive Lyapunov exponent and a noninteger value of the correlation dimension. These results turn out to be linked to a physical interpretation. The Lyapunov exponents are in agreement with the model by Akhiezer et al. [Phys. Rep. 203, 289 (1991)], based on the equivalence between the ion motion along the crystal plane described as a "string of strings" and the "kicked" rotator. The nonintegral value of the correlation dimension can be explained by the nonconservation of transverse energy at the transition.

  6. The relativistic solar particle event of 2005 January 20: prompt and delayed particle acceleration

    CERN Document Server

    Klein, K -L; Bouratzis, C; Grechnev, V; Hillaris, A; Preka-Papadema, P

    2014-01-01

    The highest energies of solar energetic nucleons detected in space or through gamma-ray emission in the solar atmosphere are in the GeV range. Where and how the particles are accelerated is still controversial. We search for observational evidence on the acceleration region(s) by comparing the timing of relativistic protons detected at Earth and radiative signatures in the solar atmosphere. To this end a detailed comparison is undertaken of the double-peaked time profile of relativistic protons, derived from the worldwide network of neutron monitors during the large particle event of 2005 January 20, with UV imaging and radio petrography over a broad frequency band from the low corona to interplanetary space. We show that both relativistic proton releases to interplanetary space were accompanied by distinct episodes of energy release and electron acceleration in the corona traced by the radio emission and by brightenings of UV kernels in the low solar atmosphere. The timing of electromagnetic emissions and re...

  7. Search for Free Fractional Electric Charge Elementary Particles Using an Automated Millikan Oil Drop Technique

    Energy Technology Data Exchange (ETDEWEB)

    Halyo, V.; Kim, P.; Lee, E. R.; Lee, I. T.; Loomba, D.; Perl, M. L.

    2000-03-20

    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied--about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71x10{sup -22} particles per nucleon with 95% confidence. (c) 2000 The American Physical Society.

  8. Search for Free Fractional Electric Charge Elementary Particles Using an Automated Millikan Oil Drop Technique

    Science.gov (United States)

    Halyo, V.; Kim, P.; Lee, E. R.; Lee, I. T.; Loomba, D.; Perl, M. L.

    2000-03-01

    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied-about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e ( e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71×10-22 particles per nucleon with 95% confidence.

  9. The search for free particles with fractional charge;Experimental survey and new results.

    Science.gov (United States)

    Halyo, Valerie; Kim, Peter; Lee, Eric R.; Lee, Irwin T.; Loomba, Dinesh; Perl, Martin L.

    2000-04-01

    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied--- about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71×10-22 particles per nucleon with 95% confidence.

  10. A simple method to increase the current range of the TERA chip in charged particle therapy applications

    Science.gov (United States)

    Cirio, R.; Fausti, F.; Fanola Guarachi, L.; Giordanengo, S.; Marchetto, F.; Mazza, G.; Monaco, V.; Sacchi, R.; Talpacci, E.; Varasteh Anvar, M.; Vignati, A.

    2015-10-01

    The development of the next generation of accelerators for charged particle radiotherapy aims to reduce dimensions and operational complexity of the machines by engineering pulsed beams accelerators. The drawback is the increased difficulty to monitor the beam delivery. Within each pulse, instantaneous currents larger by two to three orders of magnitude than present applications are expected, which would saturate the readout of the monitor chambers. In this paper, we report of a simple method to increase by almost two orders of magnitude the current range of an Application Specific Integrated Circuit chip previously developed by our group to read out monitor ionization chambers.

  11. A simple method to increase the current range of the TERA chip in charged particle therapy applications

    Energy Technology Data Exchange (ETDEWEB)

    Cirio, R. [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy); Dipartimento di Fisica dell' Università di Torino, via P. Giuria,1, 10125 Torino (Italy); Fausti, F. [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy); Dipartimento di Elettronica e Telecomunicazioni del Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino (Italy); Fanola Guarachi, L. [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy); Dipartimento di Fisica dell' Università di Torino, via P. Giuria,1, 10125 Torino (Italy); Giordanengo, S., E-mail: Simona.Giordanengo@to.infn.it [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy); Marchetto, F.; Mazza, G. [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy); Monaco, V.; Sacchi, R. [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy); Dipartimento di Fisica dell' Università di Torino, via P. Giuria,1, 10125 Torino (Italy); Talpacci, E. [Dipartimento di Fisica dell' Università di Torino, via P. Giuria,1, 10125 Torino (Italy); Varasteh Anvar, M. [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy); Dipartimento di Fisica dell' Università di Torino, via P. Giuria,1, 10125 Torino (Italy); Vignati, A. [Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria,1, 10125 Torino (Italy)

    2015-10-21

    The development of the next generation of accelerators for charged particle radiotherapy aims to reduce dimensions and operational complexity of the machines by engineering pulsed beams accelerators. The drawback is the increased difficulty to monitor the beam delivery. Within each pulse, instantaneous currents larger by two to three orders of magnitude than present applications are expected, which would saturate the readout of the monitor chambers. In this paper, we report of a simple method to increase by almost two orders of magnitude the current range of an Application Specific Integrated Circuit chip previously developed by our group to read out monitor ionization chambers.

  12. Charge collection efficiency of GaAs detectors studied with low-energy heavy charged particles

    CERN Document Server

    Bates, R; Linhart, V; O'Shea, V; Pospísil, S; Raine, C; Smith, K; Sinor, M; Wilhelm, I

    1999-01-01

    Epitaxially grown GaAs layers have recently been produced with sufficient thickness and low enough free carrier concentration to permit their use as radiation detectors. Initial tests have shown that the epi-material behaves as a classical semiconductor as the depletion behaviour follows the square root dependency on the applied bias. This article presents the results of measurements of the growth of the active depletion depth with increasing bias using low-energy protons and alpha particles as probes for various depths and their comparison to values extrapolated from capacitance measurements. From the proton and alpha particle spectroscopic measurements, an active depth of detector material that collects 100% of the charge generated inside it was determined. The consistency of these results with independent capacitance measurements supports the idea that the GaAs epi-material behaves as a classical semiconductor. (author)

  13. Experimental particle acceleration by water evaporation induced by shock waves

    Science.gov (United States)

    Scolamacchia, T.; Alatorre Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Cimarelli, C.

    2010-12-01

    Shock waves are commonly generated during volcanic eruptions. They induce sudden changes in pressure and temperature causing phase changes. Nevertheless, their effects on flowfield properties are not well understood. Here we investigate the role of gas expansion generated by shock wave propagation in the acceleration of ash particles. We used a shock tube facility consisting of a high-pressure (HP) steel autoclave (450 mm long, 28 mm in internal diameter), pressurized with Ar gas, and a low-pressure tank at atmospheric conditions (LP). A copper diaphragm separated the HP autoclave from a 180 mm tube (PVC or acrylic glass) at ambient P, with the same internal diameter of the HP reservoir. Around the tube, a 30 cm-high acrylic glass cylinder, with the same section of the LP tank (40 cm), allowed the observation of the processes occurring downstream from the nozzle throat, and was large enough to act as an unconfined volume in which the initial diffracting shock and gas jet expand. All experiments were performed at Pres/Pamb ratios of 150:1. Two ambient conditions were used: dry air and air saturated with steam. Carbon fibers and glass spheres in a size range between 150 and 210 μm, were placed on a metal wire at the exit of the PVC tube. The sudden decompression of the Ar gas, due to the failure of the diaphragm, generated an initial air shock wave. A high-speed camera recorded the processes between the first 100 μsec and several ms after the diaphragm failure at frame rates ranging between 30,000 and 50,000 fps. In the experiments with ambient air saturated with steam, the high-speed camera allowed to visualize the condensation front associated with the initial air shock; a maximum velocity of 788 m/s was recorded, which decreases to 524 m/s at distance of 0.5 ±0.2 cm, 1.1 ms after the diaphragm rupture. The condensation front preceded the Ar jet front exhausting from the reservoir, by 0.2-0.5 ms. In all experiments particles velocities following the initial

  14. Acceleration of inertial particles in wall bounded flows: DNS and LES with stochastic modelling of the subgrid acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Zamansky, Remi; Vinkovic, Ivana; Gorokhovski, Mikhael, E-mail: ivana.vinkovic@univ-lyonl.fr [Laboratoire de Mecanique des Fluides et d' Acoustique CNRS UMR 5509 Ecole Centrale de Lyon, 36, av. Guy de Collongue, 69134 Ecully Cedex (France)

    2011-12-22

    Inertial particle acceleration statistics are analyzed using DNS for turbulent channel flow. Along with effects recognized in homogeneous isotropic turbulence, an additional effect is observed due to high and low speed vortical structures aligned with the channel wall. In response to those structures, particles with moderate inertia experience strong longitudinal acceleration variations. DNS is also used in order to assess LES-SSAM (Subgrid Stochastic Acceleration Model), in which an approximation to the instantaneous non-filtered velocity field is given by simulation of both, filtered and residual, accelerations. This approach allow to have access to the intermittency of the flow at subgrid scale. Advantages of LES-SSAM in predicting particle dynamics in the channel flow at a high Reynolds number are shown.

  15. Particle-in-Cell Codes for plasma-based particle acceleration

    CERN Document Server

    Pukhov, Alexander

    2016-01-01

    Basic principles of particle-in-cell (PIC ) codes with the main application for plasma-based acceleration are discussed. The ab initio full electromagnetic relativistic PIC codes provide the most reliable description of plasmas. Their properties are considered in detail. Representing the most fundamental model, the full PIC codes are computationally expensive. The plasma-based acceler- ation is a multi-scale problem with very disparate scales. The smallest scale is the laser or plasma wavelength (from one to hundred microns) and the largest scale is the acceleration distance (from a few centimeters to meters or even kilometers). The Lorentz-boost technique allows to reduce the scale disparity at the costs of complicating the simulations and causing unphysical numerical instabilities in the code. Another possibility is to use the quasi-static approxi- mation where the disparate scales are separated analytically.

  16. Search for multiply charged Heavy Stable Charged Particles in data collected with the CMS detector

    Energy Technology Data Exchange (ETDEWEB)

    Veeraraghavan, Venkatesh [Florida State Univ., Tallahassee, FL (United States)

    2013-10-30

    Several models of new physics yield particles that are massive, long-lived, and have an electric charge, Q, greater than that of the electron, e. A search for evidence of such particles was performed using 5.0 fb-1 and 18.8 fb-1 of proton-proton collision data collected at √s = 7 TeV and √s = 8 TeV, respectively, with the Compact Muon Solenoid detector at the Large Hadron Collider. The distinctive detector signatures of these particles are that they are slow-moving and highly ionizing. Ionization energy loss and time-of- flight measurements were made using the inner tracker and the muon system, respectively. The search is sensitive to 1e ≤ |Q| ≤ 8e. Data were found to be consistent with standard model expectations and upper limits on the production cross section of these particles were computed using a Drell-Yan-like production model. Masses below 517, 687, 752, 791, 798, 778, 753, and 724 GeV are excluded for |Q| = 1e, 2e, 3e, 4e, 5e, 6e, 7e, and 8e, respectively.

  17. Real-time diagnostic for charging and damage of dielectrics in accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Shchelkunov, S.V., E-mail: sergey.shchelkunov@gmail.com [Omega-P, Inc, New Haven, CT 06511 (United States); Yale University, New Haven, CT (United States); Marshall, T.C.; Hirshfield, J.L. [Omega-P, Inc, New Haven, CT 06511 (United States)

    2016-09-01

    We report on the progress made during the initial stage of our research to study charging rate and charge distribution in a thin walled dielectric wakefield accelerator (DWA) from a passing charge bunch and the physics of conductivity and discharge phenomena in dielectric materials useful in accelerator applications. The issue is the role played by the beam halo and intense wakefields in charging the dielectric, possibly leading to undesired deflection of charge bunches and degradation of the dielectric material: the effects that may grow over many pulses, albeit perhaps differently at different repetition rates. During the initial stage of development, a microwave apparatus was built and signal processing was developed to observe time-dependent charging of dielectric surfaces and/or plasmas located on or near the inner surface of a thin-wall hollow dielectric tube. Three frequencies were employed to improve the data handling rate and the signal-to-noise. The test and performance results for a plasma test case are presented; in particular, the performance of the test unit shows capability to detect small changes ~0.1% of a dielectric constant, which would correspond to the scraping-off of only 0.3 nC to the walls of the dielectric liner inside the cavity from the passing charge bunch.

  18. Real-time diagnostic for charging and damage of dielectrics in accelerators

    Science.gov (United States)

    Shchelkunov, S. V.; Marshall, T. C.; Hirshfield, J. L.

    2016-09-01

    We report on the progress made during the initial stage of our research to study charging rate and charge distribution in a thin walled dielectric wakefield accelerator (DWA) from a passing charge bunch and the physics of conductivity and discharge phenomena in dielectric materials useful in accelerator applications. The issue is the role played by the beam halo and intense wakefields in charging the dielectric, possibly leading to undesired deflection of charge bunches and degradation of the dielectric material: the effects that may grow over many pulses, albeit perhaps differently at different repetition rates. During the initial stage of development, a microwave apparatus was built and signal processing was developed to observe time-dependent charging of dielectric surfaces and/or plasmas located on or near the inner surface of a thin-wall hollow dielectric tube. Three frequencies were employed to improve the data handling rate and the signal-to-noise. The test and performance results for a plasma test case are presented; in particular, the performance of the test unit shows capability to detect small changes 0.1% of a dielectric constant, which would correspond to the scraping-off of only 0.3 nC to the walls of the dielectric liner inside the cavity from the passing charge bunch.

  19. How to model the interaction of charged Janus particles

    Science.gov (United States)

    Hieronimus, Reint; Raschke, Simon; Heuer, Andreas

    2016-08-01

    We analyze the interaction of charged Janus particles including screening effects. The explicit interaction is mapped via a least square method on a variable number n of systematically generated tensors that reflect the angular dependence of the potential. For n = 2 we show that the interaction is equivalent to a model previously described by Erdmann, Kröger, and Hess (EKH). Interestingly, this mapping is for n = 2 not able to capture the subtleties of the interaction for small screening lengths. Rather, a larger number of tensors has to be used. We find that the characteristics of the Janus type interaction plays an important role for the aggregation behavior. We obtained cluster structures up to the size of 13 particles for n = 2 and 36 and screening lengths κ-1 = 0.1 and 1.0 via Monte Carlo simulations. The influence of the screening length is analyzed and the structures are compared to results for an electrostatic-type potential and for the multipole-expanded Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. We find that a dipole-like potential (EKH or dipole DLVO approximation) is not able to sufficiently reproduce the anisotropy effects of the potential. Instead, a higher order expansion has to be used to obtain cluster structures that are compatible with experimental observations. The resulting minimum-energy clusters are compared to those of sticky hard sphere systems. Janus particles with a short-range screened interaction resemble sticky hard sphere clusters for all considered particle numbers, whereas for long-range screening even very small clusters are structurally different.

  20. Weakly nonlinear electrophoresis of a highly charged colloidal particle

    Science.gov (United States)

    Schnitzer, Ory; Zeyde, Roman; Yavneh, Irad; Yariv, Ehud

    2013-05-01

    At large zeta potentials, surface conduction becomes appreciable in thin-double-layer electrokinetic transport. In the linear weak-field regime, where this effect is quantified by the Dukhin number, it is manifested in non-Smoluchowski electrophoretic mobilities. In this paper we go beyond linear response, employing the recently derived macroscale model of Schnitzer and Yariv ["Macroscale description of electrokinetic flows at large zeta potentials: Nonlinear surface conduction," Phys. Rev. E 86, 021503 (2012), 10.1103/PhysRevE.86.021503] as the infrastructure for a weakly nonlinear analysis of spherical-particle electrophoresis. A straightforward perturbation in the field strength is frustrated by the failure to satisfy the far-field conditions, representing a non-uniformity of the weak-field approximation at large distances away from the particle, where salt advection becomes comparable to diffusion. This is remedied using inner-outer asymptotic expansions in the spirit of Acrivos and Taylor ["Heat and mass transfer from single spheres in Stokes flow," Phys. Fluids 5, 387 (1962), 10.1063/1.1706630], with the inner region representing the particle neighborhood and the outer region corresponding to distances scaling inversely with the field magnitude. This singular scheme furnishes an asymptotic correction to the electrophoretic velocity, proportional to the applied field cubed, which embodies a host of nonlinear mechanisms unfamiliar from linear electrokinetic theories. These include the effect of induced zeta-potential inhomogeneity, animated by concentration polarization, on electro-osmosis and diffuso-osmosis; bulk advection of salt; nonuniform bulk conductivity; Coulomb body forces acting on bulk volumetric charge; and the nonzero electrostatic force exerted upon the otherwise screened particle-layer system. A numerical solution of the macroscale model validates our weakly nonlinear analysis.

  1. Thin current sheets in collisionless plasma: Equilibrium structure, plasma instabilities, and particle acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Zelenyi, L. M.; Malova, H. V.; Artemyev, A. V.; Popov, V. Yu.; Petrukovich, A. A. [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2011-02-15

    The review is devoted to plasma structures with an extremely small transverse size, namely, thin current sheets that have been discovered and investigated by spacecraft observations in the Earth's magnetotail in the last few decades. The formation of current sheets is attributed to complicated dynamic processes occurring in a collisionless space plasma during geomagnetic perturbations and near the magnetic reconnection regions. The models that describe thin current structures in the Earth's magnetotail are reviewed. They are based on the assumption of the quasi-adiabatic ion dynamics in a relatively weak magnetic field of the magnetotail neutral sheet, where the ions can become unmagnetized. It is shown that the ion distribution can be represented as a function of the integrals of particle motion-the total energy and quasi-adiabatic invariant. Various modifications of the initial equilibrium are considered that are obtained with allowance for the currents of magnetized electrons, the contribution of oxygen ions, the asymmetry of plasma sources, and the effects related to the non-Maxwellian particle distributions. The theoretical results are compared with the observational data from the Cluster spacecraft mission. Various plasma instabilities developing in thin current sheets are investigated. The evolution of the tearing mode is analyzed, and the parameter range in which the mode can grow are determined. The paradox of complete stabilization of the tearing mode in current sheets with a nonzero normal magnetic field component is thereby resolved based on the quasi-adiabatic model. It is shown that, over a wide range of current sheet parameters and the propagation directions of large-scale unstable waves, various modified drift instabilities-kink and sausage modes-can develop in the system. Based on the concept of a turbulent electromagnetic field excited as a result of the development and saturation of unstable waves, a mechanism for charged particle

  2. A compilation of charged-particle induced thermonuclear reaction rates

    CERN Document Server

    Angulo, C; Rayet, M; Descouvemont, P; Baye, D; Leclercq-Willain, C; Coc, A; Barhoumi, S; Aguer, P; Rolfs, C; Kunz, R; Hammer, J W; Mayer, A; Paradelis, T; Kossionides, S; Chronidou, C; Spyrou, K; Degl'Innocenti, S; Fiorentini, G; Ricci, B; Zavatarelli, S; Providência, C; Wolters, H; Soares, J; Grama, C; Rahighi, J; Shotter, A; Rachti, M L

    1999-01-01

    Low-energy cross section data for 86 charged-particle induced reactions involving light (1 <= Z <= 14), mostly stable, nuclei are compiled. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from 10 sup 6 K to 10 sup 1 sup 0 K are calculated. These evaluations assume either that the target nuclei are in their ground state, or that the target states are thermally populated following a Maxwell-Boltzmann distribution, except in some cases involving isomeric states. Adopted values complemented with lower and upper limits of the rates are presented in tabular form. Analytical approximations to the adopted rates, as well as to the inverse/direct rate ratios, are provided.

  3. A compilation of charged-particle induced thermonuclear reaction rates

    Energy Technology Data Exchange (ETDEWEB)

    Angulo, C.; Arnould, M.; Rayet, M.; Descouvemont, P.; Baye, D.; Leclercq-Willain, C.; Coc, A.; Barhoumi, S.; Aguer, P.; Rolfs, C.; Kunz, R.; Hammer, J.W.; Mayer, A.; Paradellis, T.; Kossionides, S.; Chronidou, C.; Spyrou, K.; Degl' Innocenti, S.; Fiorentini, G.; Ricci, B.; Zavatarelli, S.; Providencia, C.; Wolters, H.; Soares, J.; Grama, C.; Rahighi, J.; Shotter, A.; Rachti, M. Lamehi

    1999-08-23

    Low-energy cross section data for 86 charged-particle induced reactions involving light (1 {<=} Z {<=} 14), mostly stable, nuclei are compiled. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from 10{sup 6} K to 10{sup 10} K are calculated. These evaluations assume either that the target nuclei are in their ground state, or that the target states are thermally populated following a Maxwell-Boltzmann distribution, except in some cases involving isomeric states. Adopted values complemented with lower and upper limits of the rates are presented in tabular form. Analytical approximations to the adopted rates, as well as to the inverse/direct rate ratios, are provided.

  4. The ST environment: Expected charged particle radiation levels

    Science.gov (United States)

    Stassinopoulos, E. G.

    1978-01-01

    The external (surface incident) charged particle radiation, predicted for the ST satellite at the three different mission altitudes, was determined in two ways: (1) by orbital flux-integration and (2) by geographical instantaneous flux-mapping. The latest standard models of the environment were used in this effort. Magnetic field definitions for three nominal circular trajectories and for the geographic mapping positions were obtained from a current field model. Spatial and temporal variations or conditions affecting the static environment models were considered and accounted for, wherever possible. Limited shielding and dose evaluations were performed for a simple geometry. Results, given in tabular and graphical form, are analyzed, explained, and discussed. Conclusions are included.

  5. Charged particle spectra in p+Pb collisions

    CERN Document Server

    Shulga, Evgeny; The ATLAS collaboration

    2016-01-01

    Per-event charged particle spectra and nuclear modification factors are measured with the ATLAS detector at the LHC in p+Pbinteractions at sqrt(s_NN)=5.02 TeV. Results are presented as a function of transverse momentum, rapidity, and in different intervals of collision centrality, which is characterised in p+Pb collisions by the total transverse energy measured over the pseudorapidity interval -3.2

  6. Iron free permanent magnet systems for charged particle beam optics

    Energy Technology Data Exchange (ETDEWEB)

    Lund, S.M.; Halbach, K.

    1995-09-03

    The strength and astounding simplicity of certain permanent magnet materials allow a wide variety of simple, compact configurations of high field strength and quality multipole magnets. Here we analyze the important class of iron-free permanent magnet systems for charged particle beam optics. The theory of conventional segmented multipole magnets formed from uniformly magnetized block magnets placed in regular arrays about a circular magnet aperture is reviewed. Practical multipole configurations resulting are presented that are capable of high and intermediate aperture field strengths. A new class of elliptical aperture magnets is presented within a model with continuously varying magnetization angle. Segmented versions of these magnets promise practical high field dipole and quadrupole magnets with an increased range of applicability.

  7. Lorentz Covariant Canonical Symplectic Algorithms for Dynamics of Charged Particles

    CERN Document Server

    Wang, Yulei; Qin, Hong

    2016-01-01

    In this paper, the Lorentz covariance of algorithms is introduced. Under Lorentz transformation, both the form and performance of a Lorentz covariant algorithm are invariant. To acquire the advantages of symplectic algorithms and Lorentz covariance, a general procedure for constructing Lorentz covariant canonical symplectic algorithms (LCCSA) is provided, based on which an explicit LCCSA for dynamics of relativistic charged particles is built. LCCSA possesses Lorentz invariance as well as long-term numerical accuracy and stability, due to the preservation of discrete symplectic structure and Lorentz symmetry of the system. For situations with time-dependent electromagnetic fields, which is difficult to handle in traditional construction procedures of symplectic algorithms, LCCSA provides a perfect explicit canonical symplectic solution by implementing the discretization in 4-spacetime. We also show that LCCSA has built-in energy-based adaptive time steps, which can optimize the computation performance when th...

  8. Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism

    CERN Document Server

    Guo, Xinyi; Narayan, Ramesh

    2014-01-01

    Electron acceleration to non-thermal energies in low Mach number (M<5) shocks is revealed by radio and X-ray observations of galaxy clusters and solar flares, but the electron acceleration mechanism remains poorly understood. Diffusive shock acceleration, also known as first-order Fermi acceleration, cannot be directly invoked to explain the acceleration of electrons. Rather, an additional mechanism is required to pre-accelerate the electrons from thermal to supra-thermal energies, so they can then participate in the Fermi process. In this work, we use two- and three-dimensional particle-in-cell plasma simulations to study electron acceleration in low Mach number shocks. We focus on the particle energy spectra and the acceleration mechanism in a reference run with M=3. We find that about 15 percent of the electrons can be efficiently accelerated, forming a non-thermal power-law tail in the energy spectrum with a slope of p~2.4. Initially, thermal electrons are energized at the shock front via shock drift a...

  9. Investigation of the Dispersion Behavior of Inertial Particles within Accelerated Domain

    Directory of Open Access Journals (Sweden)

    Tong ZHAO

    2015-01-01

    Full Text Available This report presents a study of the dynamics dispersion behaviors of inertial particle in solid-air two-phase flow within accelerated domains using both experimental and simulation approaches. In the simulation, a threedimensional model was proposed by means of the combined computational fluid dynamics and a discrete element method (CFD-DEM. The simulation model provides information regarding the particle distribution behaviors and the particle run-away rate from the calculation domain. In the experiment, particle image velocimetry (PIV and laser tomography were used to measure the particle velocity and concentration distribution, respectively. The simulation results were than validated by the experimental measurement. And the influence mechanisms of acceleration on the particle flow behavior were discussed in detail. As results, acceleration of the calculation domain affects the particle motion and causes a relative dense particles distribution in the accelerated direction. The particle run-out rate under acceleration was initially the same, but subsequently lower than that of the condition without acceleration. This finding shows that the acceleration adversely affects the particle run-out rate.

  10. Beam manipulation techniques, nonlinear beam dynamics, and space charge effect in high energy high power accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S. Y.

    2014-04-07

    We had carried out a design of an ultimate storage ring with beam emittance less than 10 picometer for the feasibility of coherent light source at X-ray wavelength. The accelerator has an inherent small dynamic aperture. We study method to improve the dynamic aperture and collective instability for an ultimate storage ring. Beam measurement and accelerator modeling are an integral part of accelerator physics. We develop the independent component analysis (ICA) and the orbit response matrix method for improving accelerator reliability and performance. In collaboration with scientists in National Laboratories, we also carry out experimental and theoretical studies on beam dynamics. Our proposed research topics are relevant to nuclear and particle physics using high brightness particle and photon beams.

  11. Measurements of Accelerations of Large Neutrally-buoyant Particles in Intense Turbulence

    CERN Document Server

    Brown, Rachel D; Voth, Greg A

    2009-01-01

    We measure acceleration statistics of neutrally buoyant spherical particles with diameter 0.4 , clearly resolve the transition from the tracer like behavior of small particles to the much smaller accelerations of large particles. For d>5 eta, decreases with diameter as d^{-2/3} in agreement with inertial range scaling arguments. A model relating to the pressure structure functions matches the transition from small to large particle behavior if the particles respond to pressure differences over (1.7 +- 0.3) d. A model relating to the fluid acceleration averaged over the particle diameter predicts the transition with no free parameters, but does not show clean inertial range scaling in the size range studied. Consistent with earlier work, we find that the scaled acceleration probability density function shows very little dependence on particle size.

  12. Laser acceleration of electrons to giga-electron-volt energies using highly charged ions.

    Science.gov (United States)

    Hu, S X; Starace, Anthony F

    2006-06-01

    The recent proposal to use highly charged ions as sources of electrons for laser acceleration [S. X. Hu and A. F. Starace, Phys. Rev. Lett. 88, 245003 (2002)] is investigated here in detail by means of three-dimensional, relativistic Monte Carlo simulations for a variety of system parameters, such as laser pulse duration, ionic charge state, and laser focusing spot size. Realistic laser focusing effects--e.g., the existence of longitudinal laser field components-are taken into account. Results of spatial averaging over the laser focus are also presented. These numerical simulations show that the proposed scheme for laser acceleration of electrons from highly charged ions is feasible with current or near-future experimental conditions and that electrons with GeV energies can be obtained in such experiments.

  13. Particle motion of accelerated electrons in standing-wave RF structures

    Science.gov (United States)

    Hammen, A. F. J.; Corstens, J. M.; Botman, J. I. M.; Hagedoorn, H. L.; Theuws, W. H. C.

    1999-05-01

    A Hamiltonian theory has been formulated, which is used to calculate accelerated particle motion in standing-wave RF structures. In particular, these calculations have been applied to the Eindhoven racetrack microtron accelerating cavity. The calculations are in excellent agreement with simulations performed by particle-tracking codes.

  14. DC-like Phase Space Manipulation and Particle Acceleration Using Chirped AC Fields

    Energy Technology Data Exchange (ETDEWEB)

    P.F. Schmit and N.J. Fisch

    2009-06-17

    Waves in plasmas can accelerate particles that are resonant with the wave. A DC electric field also accelerates particles, but without a resonance discrimination, which makes the acceleration mechanism profoundly different. We investigate the effect on a Hamiltonian distribution of an accelerating potential waveform, which could, for example, represent the average ponderomotive effect of two counterpropagating electromagnetic waves. In particular, we examine the apparent DC-like time-asymptotic response of the distribution in regimes where the potential structure is accelerated adiabatically. A highly resonant population within the distribution is always present, and we characterize its nonadiabatic response during wave-particle resonance using an integral method in the noninertial reference frame moving with the wave. Finally, we show that in the limit of infinitely slow acceleration of the wave, these highly resonant particles disappear and the response

  15. Parameters of the Disk Loaded Waveguide structure for intermediate particles acceleration in the intermediate energy range

    CERN Document Server

    Paramonov, V

    2013-01-01

    The Disk Loaded Waveguide (DLW) is the mostly used high frequency structure for acceleration of lightweight particles - electrons in the high energy range. In some physical experiments acceleration of more heavy particles - muons to medium energies is required. DLW parameters are considered for particle velocity 0.04 < \\beta < 1 both for the fundamental and the nearest backward spatial harmonics. Physical and technical restrictions for DLW application in the low \\beta range and lower frequency (the L-band range) are analyzed. Basing on particularities of acceleration with Traveling Wave (TW), deep optimization of DLW cells dimensions, the choice of optimal operating phase advance for each DLW section and combination of forward and backward TW modes, it is possible to create simple, cost effective acceleration system for acceleration in the velocity range 0.2 < \\beta < 1 intermediate particles, in some parameters overcoming accelerating system with RF cavities in Standing Wave (SW) mode. Design cri...

  16. Charged-particle beam diagnostics for the advanced photon source

    Science.gov (United States)

    Lumpkin, A. H.; Decker, G.; Kahana, E.; Patterson, D.; Sellyey, W.; Wang, X.; Chung, Y.

    1993-07-01

    Plans, prototypes, and initial test results for the charged-particle beam (e -, e +) diagnostic systems on the injector rings, their transport lines, and the storage ring for the Advanced Photon Source (APS) are presented. The APS will be a synchrotron radiation user facility with one of the world's brightest X-ray sources in the 10-keV regime. Its 200-MeV electron linac, 450-MeV positron linac, positron accumulator ring, 7-GeV injector synchrotron (IS), 7-GeV storage ring (SR), and undulator test lines will also demand the development and demonstration of key particle-beam characterization techniques over a wide range of parameter space. Some of these parameter values overlap or approach those projected for fourth generation light sources (linac-driven FELs and high brightness storage rings) as described at a recent workshop. Initial results from the diagnostics prototypes on the linac test stand operating at 45-MeV include current monitor data, beam loss monitor data, and video digitization using VME architecture.

  17. Chaotic motion of charged particles in toroidal magnetic configurations.

    Science.gov (United States)

    Cambon, Benjamin; Leoncini, Xavier; Vittot, Michel; Dumont, Rémi; Garbet, Xavier

    2014-09-01

    We study the motion of a charged particle in a tokamak magnetic field and discuss its chaotic nature. Contrary to most of recent studies, we do not make any assumption on any constant of the motion and solve numerically the cyclotron gyration using Hamiltonian formalism. We take advantage of a symplectic integrator allowing us to make long-time simulations. First considering an idealized magnetic configuration, we add a nongeneric perturbation corresponding to a magnetic ripple, breaking one of the invariant of the motion. Chaotic motion is then observed and opens questions about the link between chaos of magnetic field lines and chaos of particle trajectories. Second, we return to an axisymmetric configuration and tune the safety factor (magnetic configuration) in order to recover chaotic motion. In this last setting with two constants of the motion, the presence of chaos implies that no third global constant exists, we highlight this fact by looking at variations of the first order of the magnetic moment in this chaotic setting. We are facing a mixed phase space with both regular and chaotic regions and point out the difficulties in performing a global reduction such as gyrokinetics.

  18. Future trends in cancer therapy with particle accelerators

    CERN Document Server

    Amaldi, Ugo

    2004-01-01

    Hadrontherapy is the radiotherapy technique that uses protons, neutrons or carbon ions. Protons and ions, being, heavy charged particles, allow a more conformal treatment than X-rays and thus spare better the surrounding healthy tissues. By now about 35000 patients have been treated worldwide with protons and about 1600 with carbon ions. Since few years protontherapy of deep-seated tumours is booming with two hospital centres running in USA and three under construction. Four centres are treating patients in Japan. The list of constructions going on elsewhere is long: two in China, one, in Germany, one in Korea, one in Switzerland. But the future hopes for a qualitatively different radiotherapy are centred on carbon ions: they have a larger biological effectiveness than X-rays and protons and are particularly suited to treat radio resistant tumours, as indicated by the encouraging results obtained on about 1400 patients in HIMAC (Chiba, Japan) and on about 200 patients at GSI (Darmstadt). Two carbon centres ar...

  19. The "Puck" energetic charged particle detector: Design, heritage, and advancements

    Science.gov (United States)

    Clark, G.; Cohen, I.; Westlake, J. H.; Andrews, G. B.; Brandt, P.; Gold, R. E.; Gkioulidou, M. A.; Hacala, R.; Haggerty, D.; Hill, M. E.; Ho, G. C.; Jaskulek, S. E.; Kollmann, P.; Mauk, B. H.; McNutt, R. L.; Mitchell, D. G.; Nelson, K. S.; Paranicas, C.; Paschalidis, N.; Schlemm, C. E.

    2016-08-01

    Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV. This sensor makes simultaneous angular measurements of electron fluxes from the tens of keV to about 1 MeV. The same measurements can be extended down to approximately 1 keV/nucleon, with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high-voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions.

  20. Motion of charged particle in Reissner - Nordstr\\"om spacetime: A Jacobi metric approach

    CERN Document Server

    Das, Praloy; Ghosh, Subir

    2016-01-01

    The present work discusses motion of neutral and charged particles in Reissner - Nordstr\\"{o}m spacetime. The constant energy paths are derived in a variational principle framework using the Jacobi metric which is parameterized by conserved particle energy. Of particular interest is the case of particle charge and Reissner-Nordstr\\"{o}m black hole charge being of same sign since this leads to a clash of opposing forces - gravitational (attractive) and Coulomb (repulsive).