Method for charged particle beam acceleration
International Nuclear Information System (INIS)
The method of charged particle beam acceleration based on its resonance interaction with electromagnetic field of travelling wave is suggested. The electron beam is injected into waveguide in which longitudinal magnetic field and electromagnetic wave are excited. With the purpose of reducing HF-power losses in the waveguide walls, the azimuthal particle motion is synchronized with azimuthal change of longitudinal component of electric field of the accelerating electromagnetic wave. The suggested method permits to increase the efficiency and shunting resistance of the accelerating waveguide by reducing its boundary surface
VEDs for charged particle accelerators: Indian scenario
International Nuclear Information System (INIS)
In the initial times after their invention, the charged particle accelerators have, primarily, been used for fundamental studies on nuclei and atoms. From the first modern accelerator, the cathode ray tube, used by J.J. Thomson for the discovery of electron, very recently the gigantic 27 km circumference Large Hadron Collider (LHC) is operational in the search of Higg's boson and related physics issues. Particle accelerators have emerged as powerful microscopes for investigating the finest details of cells, genes, molecules, atoms, protons, neutrons, muons, electrons, quarks and, possibly, still undiscovered even more fundamental constituents of the universe, such as dark matter and dark energy. Several noble prize winning discoveries have been made using accelerators. Accelerators are now being used in a wide area of industrial and medical applications. They are used for the production of radioisotopes for medical imaging, cancer therapy, food sterilization, treatment of waste water, sterilization of medical equipment, material modification, mass spectroscopy, cargo scanning, fabrication of semiconductors etc. Ongoing effort towards the development of accelerators with megawatt beam power is showing hope for a cleaner source of nuclear energy and treatment of nuclear waste. Several tens of thousands of accelerators are presently operational in the world for basic research and applications. Development of new accelerators has several times been driven by new technologies and materials and sometimes they have driven the technological developments towards cutting edge. Some examples are ultra-high vacuum in large volumes, superfluid helium in cryogenics, cryocoolers, superconducting magnets and RF cavities, high power vacuum electronic devices, global control systems, superfast computing and communication networks, giant data storage/processing systems etc. India has been pursuing a fairly robust programme of accelerator development at various institutions. It
Electrophysical Systems Based On Charged Particle Accelerators
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...
Charged particle acceleration by electron beam in corrugated plasma waveguide
International Nuclear Information System (INIS)
A two-beam charged particle acceleration scheme in a plasma waveguide with corrugated conducting walls is considered. The guiding heavy-current relativistic electron beam is in synchronism with the first plasma wave space harmonics and the accelerated beam is synchronism with a quicker plasma wave. In this case under weak corrugation of the wall the accelerating resonance field effecting the accelerated particles notably increases the field braking the guiding beam. The process of plasma wave excitation with regard to the guiding beam space charge and the relativistic particle acceleration dynamics are investigated by numeric methods. Optimal acceleration modes are found. 19 refs.; 12 figs
Harmonic Ratcheting for Ferrite Tuned RF Acceleration of Charged Particles
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.
Uniformly Accelerating Charged Particles A Threat to the Equivalence Principle
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.
Charged spinning black holes as accelerators of spinning particles
Zhang, Yu-Peng; Wei, Shao-Wen; Yang, Jie; Liu, Yu-Xiao
2016-01-01
It is well known that some black holes can act as accelerators for particles without spin. Recently, there are some works considering collision of two spinning particles in the background of Schwarzschild and Kerr black holes and it was shown that the spin of the test particles is related to the center-of-mass energy. In this paper we extend the results to some more general cases. We consider Kerr-Newman black holes as accelerators for spinning particles. We derive the center-of-mass energy of the spinning particles and use numerical method to investigate how the center-of-mass energy is affected by the properties of the black holes and spinning particles.
International Nuclear Information System (INIS)
A charged particle trapped in an electrostatic wave is accelerated in the plane perpendicular to the wave vector k. It is found that there is an optimum angle theta = theta/sub m/ at which the particle gains a maximum energy which is about four times larger than that at theta = π/2, theta being the angle between k and the magnetic field
A New Type of Accelerator for Charged Particle Cancer Therapy
Edgecock, Rob
2016-01-01
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).
Acceleration of charged particles in ion excitation waves in the solar corona
International Nuclear Information System (INIS)
A possibility of charged particle acceleration in a shock wave of isothermal compression in the transition region between the lower corona and the upper chromosphere is considered. The shock wave motion is accompanied with emission in spectral lines of multicharged ions and helium. It follows from the results of the paper that in the bursts conditioned by the motion of shock wave fronts electrons and protons are accelerated with an equal probability approximately. The times of acceleration and particle output from the region behind the front are of the same order and independent of the particle energy, but depend only on characteristic lengths of inhomogeneities in the wave front and on its velocity
Study of charged particle acceleration by magnetic reconnection in a plasma
Directory of Open Access Journals (Sweden)
M Mehdizade
2016-02-01
Full Text Available Magnetic reconnection, which occurs in high conducting plasmas, changes the topology of magnetic field lines and converts magnetic energy into the kinetic and thermal energy of plasma and also accelerates charged particles. This phenomenon plays an important role in changing the dynamic of laboratory and space plasmas such as fusion tokamaks and sun’s corona. The electric and magnetic fields generated by magnetic reconnection result in acceleration and drift motion of charged particles. Therefore, charged particles, depending on their injection position and initial kinetic energy, can be accelerated and escape or can be trapped in magnetic fields. In this study by considering different injection positions and initial kinetic energies, we investigate how a particle (proton is accelerated or trapped. Our numerical analyses show that the spine structure for three-dimensional magnetic reconnection can be considered as a potential mechanism for particle acceleration. In this model, a proton can be accelerated up to a few MeV within a few milliseconds. The particle’s trajectory and final kinetic energy strongly depend on its injection position.
International Nuclear Information System (INIS)
Space, angular and energy distributions of the charged particle of radiation field outside the Serpukhov accelerator shielding at different protons beam energies obtained with the ΔE-E spectrometer are presented. The influence of the accelerating complex operation on the charged particles field shaping outside the concrete and heterogeneous steel-concrete shieldings has been analyzed. The ratios between neutrons and charged particles of the radiation field outside the 70 GeV accelerator shielding have been estimated
Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge
International Nuclear Information System (INIS)
The purpose of this course is to provide a comprehensive introduction to the physics of beams with intense space charge. This course is suitable for graduate students and researchers interested in accelerator systems that require sufficient high intensity where mutual particle interactions in the beam can no longer be neglected. This course is intended to give the student a broad overview of the dynamics of beams with strong space charge. The emphasis is on theoretical and analytical methods of describing the acceleration and transport of beams. Some aspects of numerical and experimental methods will also be covered. Students will become familiar with standard methods employed to understand the transverse and longitudinal evolution of beams with strong space charge. The material covered will provide a foundation to design practical architectures. In this course, we will introduce you to the physics of intense charged particle beams, focusing on the role of space charge. The topics include: particle equations of motion, the paraxial ray equation, and the Vlasov equation; 4-D and 2-D equilibrium distribution functions (such as the Kapchinskij-Vladimirskij, thermal equilibrium, and Neuffer distributions), reduced moment and envelope equation formulations of beam evolution; transport limits and focusing methods; the concept of emittance and the calculation of its growth from mismatches in beam envelope and from space-charge non-uniformities using system conservation constraints; the role of space-charge in producing beam halos; longitudinal space-charge effects including small amplitude and rarefaction waves; stable and unstable oscillation modes of beams (including envelope and kinetic modes); the role of space charge in the injector; and algorithms to calculate space-charge effects in particle codes. Examples of intense beams will be given primarily from the ion and proton accelerator communities with applications from, for example, heavy-ion fusion, spallation
De Martino, Salvatore; De Siena, Silvio; Illuminati, Fabrizio
1998-01-01
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_...
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
Pondermotive acceleration of charged particles along the relativistic jets of an accreting blackhole
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.
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.
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. PMID:19054679
Transport and Acceleration of Energetic Charged Particles near an Oblique Shock
Ruffolo, D
1999-01-01
We have developed a numerical simulation code that treats the transport and acceleration of charged particles crossing an idealized oblique, non-relativistic shock within the framework of pitch angle transport using a finite-difference method. We consider two applications: 1) to study the steady-state acceleration of energetic particles at an oblique shock, and 2) to explain observed precursors of Forbush decreases of galactic cosmic rays before the arrival of an interplanetary shock induced by solar activity. For the former, we find that there is a jump in the particle intensity at the shock, which is stronger for more oblique shocks. Detailed pitch angle distributions are also presented. The simple model of a Forbush decrease explains the key features of observed precursors, an enhanced diurnal anisotropy extending several mean free paths upstream of the shock and a depletion of particles in a narrow loss cone at ~0.1 mean free path from the shock. Such precursors have practical applications for space weath...
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...
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...
Kartavykh, Y. Y.; Dröge, W.; Kovaltsov, G. A.; Ostryakov, V. M.
2006-01-01
The effect of interplanetary propagation on the energy dependence of the iron mean ionic charge of solar cosmic rays is investigated. The diffusion convection transport equation is solved numerically making use of a Monte-Carlo approach. The interplanetary propagation results in a shift of charge spectra towards lower energies due to adiabatic deceleration which becomes stronger as the particles’ scattering mean free path decreases. Taking the above effect into account, we compare predictions of our model of charge-consistent stochastic acceleration with recent ACE observations. A detailed analysis of two particle events shows that our model can give a consistent explanation of the observed iron charge and energy spectra, and allows to put constrains on the temperature, density, and the acceleration and escape time scales in the acceleration region.
International Nuclear Information System (INIS)
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.)
Wu, S Q
2001-01-01
The Hawking radiation of Dirac particles in an arbitrarily rectilinearly accelerating Kinnersley black hole with electro-magnetic charge and cosmological constant is investigated by using method of the generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the time and the polar angle. The Hawking thermal radiation spectrum of Dirac particles is also derived. PACS numbers: 04.70.Dy, 97.60.Lf
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.
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.
Dröge, W.; Kartavykh, Y. Y.; Klecker, B.; Mason, G. M.
2006-07-01
The 1998 September 9 solar particle event was a 3He-rich solar particle event that showed a strong increase of Fe ionization states in the energy range below 1 MeV nucleon-1. We have investigated this event by fitting Wind and ACE observations using a model of acceleration and stripping near the Sun, followed by particle transport in the interplanetary medium taking into account particle focusing, pitch-angle scattering, adiabatic deceleration, and convection. The simulation provides a reconstruction of the injection function of the energetic particles released from the Sun and their time, energy, and charge dependence. We find that electrons and Fe ions are injected almost impulsively, whereas the injection of protons takes place on a much longer timescale or even consists of two distinct injection processes. We are able to obtain good overall fits to the observations. This suggests that our model can be used to obtain information about the conditions in the acceleration region such as density, temperature, and the timescales of the acceleration process, if sufficiently accurate modeling of the particle transport in the solar wind is possible.
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...
Particle Acceleration in Astrophysical Sources
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...
Energy Technology Data Exchange (ETDEWEB)
Giacalone, Joe [Department of Planetary Sciences, University of Arizona, Tucson, AZ (United States)
2015-01-20
We present results from numerical simulations of the acceleration of solar energetic particles (SEPs) associated with strong, fast, and radially propagating interplanetary shocks. We focus on the phase of the SEP event at the time of the shock passage at 1 AU, which is when the peak intensity at energies below a few MeV is the highest. The shocks in our study start between 2 and 10 solar radii and propagate beyond 1 AU. We study the effect of various shock and particle input parameters, such as the spatial diffusion coefficient, shock speed, solar wind speed, initial location of the shock, and shock deceleration rate, on the total integrated differential intensity, I, of SEPs with kinetic energies > 10 MeV. I is the integral over energy of the differential intensity spectrum at the time of the shock passage at 1 AU. We find that relatively small changes in the parameters can lead to significant event-to-event changes in I. For example, a factor of 2 increase in the diffusion coefficient at a given energy and spatial location, can lead to a decrease in I by as much as a factor of 50. This may help explain why there are fewer large SEP events seen during the current solar maximum compared to previous maxima. It is known that the magnitude of the interplanetary magnetic field is noticeably weaker this solar cycle than it was in the previous cycle and this will naturally lead to a somewhat larger diffusion coefficient of SEPs.
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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.)
International Nuclear Information System (INIS)
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.)
Method for extremal control of the beam parameters in charged particle accelerators
International Nuclear Information System (INIS)
The method of extremal control of charged particle beam parameters is suggested for the solution of the timization problem ophe IHEP boster operation mode. Motion along the estimation of drift direction with simultaneous adaptation to the value of drift rate is organized in the suggested method of extremal control. It is assumed that trajectory of the drift extremum can be approximated by the piecewise-linear function. Estimation of the drift direction is exercised on the base of fixation of two consequent positions of the extremum in the control space. The identification of the drift-direction are introduced in the algorithm of tracing the extrenum drift. Investigation of the method on the test two-dimensional square surface has shown that the method provides drift tracing within the rate of 0.01 a deg - 2 a deg where a deg - the initial working step of the stochastic approximation method. The average deviation does not exceed 0.7 a deg, and the accuracy of adaptation to the value of drift rate 10-3 K
Applications of particle accelerators
International Nuclear Information System (INIS)
Particle accelerators are now widely used in a variety of applications for scientific research, applied physics, medicine, industrial processing, while possible utilisation in power engineering is envisaged. Earlier presentations of this subject, given at previous CERN Accelerator School sessions have been updated with papers contributed to the first European Conference on Accelerators in Applied Research and Technology (ECAART) held in September 1989 in Frankfurt and to the Second European Particle Accelerator Conference in Nice in June 1990. (orig.)
Worldline deviations of charged spinning particles
Energy Technology Data Exchange (ETDEWEB)
Heydari-Fard, M. [Department of Physics, Shahid Beheshti University, Evin, 19839 Tehran (Iran, Islamic Republic of); Mohseni, M. [Physics Department, Payame Noor University, 19395-4697 Tehran (Iran, Islamic Republic of)]. E-mail: m-mohseni@pnu.ac.ir; Sepangi, H.R. [Department of Physics, Shahid Beheshti University, Evin, 19839 Tehran (Iran, Islamic Republic of); Institute for Studies in Theoretical Physics and Mathematics, Tehran (Iran, Islamic Republic of)
2005-10-20
The geodesic deviation equation is generalized to worldline deviation equations describing the relative accelerations of charged spinning particles in the framework of Dixon-Souriau equations of motion.
Worldline deviations of charged spinning particles
Heydari-Fard, M; Sepangi, H R
2005-01-01
The geodesic deviation equation is generalized to worldline deviation equations describing the relative accelerations of charged spinning particles in the framework of Dixon-Souriau equations of motion.
Charged particle driver for ICF using an accelerated, focused compact torus
International Nuclear Information System (INIS)
We report the status of evaluating an accelerated and focused compact torus as a driver for ICF. We are studying the acceleration and focusing aspects experimentally in the RACE facility, a recently completed ring generator coupled to a 260 kJ acceleration bank. Compact torus and ICF target interaction is being investigated with PIC codes and LASNEX, a 2D magneto-hydrodynamics code. Final conditions required of the CT are discussed as well as coupling issues such as superthermal electron production. We conclude with an economic evaluation of a few 100 MW reactor driven by a compact torus. 9 refs., 5 figs., 1 tab
High Energy Particle Accelerators
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. .
International Nuclear Information System (INIS)
As the Palais de la Decouverte (in Paris) is the sole scientific vulgarization establishment in the world to operate an actual particle accelerator able to provoke different types of nuclear reactions, the author recalls some historical aspects of the concerned department since the creation of the 'Radioactivity - Atom synthesis' department in 1937. He recalls the experiments which were then performed, the installation of the particle accelerator in 1964 and its renewal. He describes what's going on in this accelerator. He gives an overview of the difficulties faced after it has been decided to move it, of the works which had to be performed, and of radiation protection measures
Particle-accelerator decommissioning
International Nuclear Information System (INIS)
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
Particle-accelerator decommissioning
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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.
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...
Beam dynamics in high energy particle accelerators
Wolski, Andrzej
2014-01-01
Particle accelerators are essential tools for scientific research in fields as diverse as high energy physics, materials science and structural biology. They are also widely used in industry and medicine. Producing the optimum design and achieving the best performance for an accelerator depends on a detailed understanding of many (often complex and sometimes subtle) effects that determine the properties and behavior of the particle beam. Beam Dynamics in High Energy Particle Accelerators provides an introduction to the concepts underlying accelerator beam line design and analysis, taking an approach that emphasizes the elegance of the subject and leads into the development of a range of powerful techniques for understanding and modeling charged particle beams.
Heavy charged particle therapy
International Nuclear Information System (INIS)
A pilot study of heavy charged particles with heavy ion medical accelerator in Chiba (HIMAC) for advanced H and N cancer has been carried out from June 1994 at National Institute of Radiological Sciences (NIRS). As of the beginning of August 1994, three patients were treated by 290 MeV carbon ions. The patients had adenocarcinoma of the cheek mucosa, squamous cell carcinoma of the ethmoid sinus and adenoid cystic carcinoma of the sublingual gland. Patients were immobilized by individual head coach and thermosplint facial shell. Individual collimators and bolus were also prepared for each ports. Dose fractionation for the initial pilot study group was 16.2 GyE/18 fractions/6 weeks, which would be equivalent to standard fractionation of 60.0 Gy/30 fractions/6 weeks with photons. This dose fractionation was considered to be 20% lesser than 75 GyE/37.5 fractions/7.5 weeks, which is estimated to be maximum tolerance dose for advanced H and N cancers. HIMAC worked well and there was no major trouble causing any treatment delay. Acute skin reactions of 3 patients were 2 cases of bright erythema with patchy moist desquamation and one of dull erythema, which were evaluated as equivalent reaction with irradiated dose. Acute mucosa reactions appeared to have lesser reaction than predicted mucositis. Tumor reactions of three patients were partial reaction (PR) at the end of treatment and nearly complete remission (CR) after 6 months of treatment. From October 1994, we started to treat patients with advanced H and N cancer with 10% high dose than previous dose. And new candidates of pilot study with non small cell lung cancer, brain tumor and carcinoma of the tongue were entered into pilot study. At the end of February 1995, a total of 21 patients were treated by carbon ions. (J.P.N.)
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...
Particle acceleration in space and laboratory plasmas
International Nuclear Information System (INIS)
The general principle of charged particle acceleration in space and laboratory plasmas is illustrated by a discussion of particular types of acceleration mechanisms which can be classified as either deterministic processes or stochastic processes. Acceleration by parallel electric fields, produced in double layers is an example of a deterministic process. Fermi acceleration and acceleration by turbulent wave fields are examples of stochastic processes. The physical acceleration mechanism involved in each type of process is discussed and examples given for space and laboratory plasmas. (author)
Particle acceleration by pulsars
International Nuclear Information System (INIS)
The evidence that pulsars accelerate relativistic particles is reviewed, with emphasis on the γ-ray observations. The current state of knowledge of acceleration in strong waves is summarized, with emphasis on the inability of consistent theories to accelerate very high energy particles without converting too much energy into high energy photons. The state of viable models for pair creation by pulsars is summarized, with the conclusion that pulsars very likely lose rotational energy in winds instead of in superluminous strong waves. The relation of the pair creation models to γ-ray observations and to soft X-ray observations of pulsars is outlined, with the conclusion that energetically viable models may exist, but none have yet yielded useful agreement with the extant data. Some paths for overcoming present problems are discussed. The relation of the favored models to cosmic rays is discussed. It is pointed out that the pairs made by the models may have observable consequences for observation of positrons in the local cosmic ray flux and for observations of the 511 keV line from the interstellar medium. Another new point is that asymmetry of plasma supply from at least one of the models may qualitatively explain the gross asymmetry of the X-ray emission from the Crab nebula. It is also argued that acceleration of cosmic ray nuclei by pulsars, while energetically possible, can occur only at the boundary of the bubbles blown by the pulsars, if the cosmic ray composition is to be anything like that of the known source spectrum
Microwave View on Particle Acceleration in Flares
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...
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.
Particle Acceleration in 3D Magnetic Reconnection
Dahlin, J.; Drake, J. F.; Swisdak, M.
2015-12-01
Magnetic reconnection is an important driver of energetic particles in phenomena such as magnetospheric storms and solar flares. Using kinetic particle-in-cell (PIC) simulations, we show that the stochastic magnetic field structure which develops during 3D reconnection plays a vital role in particle acceleration and transport. In a 2D system, electrons are trapped in magnetic islands which limits their energy gain. In a 3D system, however, the stochastic magnetic field enables the energetic electrons to access volume-filling acceleration regions and therefore gain energy much more efficiently than in the 2D system. We also examine the relative roles of two important acceleration drivers: parallel electric fields and a Fermi mechanism associated with reflection of charged particles from contracting field lines. We find that parallel electric fields are most important for accelerating low energy particles, whereas Fermi reflection dominates energetic particle production. We also find that proton energization is reduced in the 3D system.
Acceleration of Particles in Imbalanced Magnetohydrodynamic Turbulence
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.
Acceleration of particles in imbalanced magnetohydrodynamic turbulence.
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.
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.
Particle accelerator; the Universe machine
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."
Particle acceleration in modified shocks
International Nuclear Information System (INIS)
Efficient particle acceleration in shocks must modify the shock structure with consequent changes in the particle acceleration. This effect is studied and analytic solutions are found describing the diffusive acceleration of particles with momentum independent diffusion coefficients in hyperbolic tangent type velocity transitions. If the input particle spectrum is a delta function, the shock smoothing replaces the truncated power-law downstream particle spectrum by a more complicated form, but one which has a power-law tail at high momenta. For a cold plasma this solution can be made completely self-consistent. Some problems associated with momentum dependent diffusion coefficients are discussed. (author)
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.
EXHIBITION: Accelerated Particles
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:...
EXHIBITION: Accelerated Particles
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 ...
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.
Mass-independent search for fractionally charged particles
International Nuclear Information System (INIS)
A proposed mass-independent search for fractionally charged particles with the all-electrostatic line of the IsoTRACE Laboratory at University of Toronto is described. Sensitive measurement of the fractional charge is accomplished by (1) a judicious choice of ion source and ion species, (2) charge changing and electrostatic analysis before injection into the tandem accelerator, (3) molecular destruction, charge changing, and acceleration by the tandem, (4) charge state selection and E/q analysis after acceleration, and (5) particle energy measurement with a Si surface barrier detector. In addition, the mass of the fractionally charged particles can be determined by a time of flight spectrometer. Specific cases involving +- (1/3)e and +- (2/3)e particles are discussed. Also included in the discussion are: integral charge background rejection, the procedure of the search, the signature of the fractionally charged particles, he resolutions of the analyzers and detectors, and the expected energy and time of flight spectra
Studying Charged Particle Optics: An Undergraduate Course
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…
Particle accelerators and scientific culture
International Nuclear Information System (INIS)
A historical review of fifty years of physics around particle accelerators, from the first nuclear reactions produced by beams of artificially accelerated particles to the large multinational projects now under discussion. The aim is to show how our description of natural phenomena has been shaped by advances in theoretical understanding, the development of new techniques, and the characters of men. Large use has been made of quotations from many of the scientists involved. (Auth.)
Particle accelerators and scientific culture
International Nuclear Information System (INIS)
A historical review of fifty years of physics around particle accelerators, from the first nuclear reactions produced by beams of artificially accelerated particles to the large multinational projects now under discussion. The aim is to show how the description of natural phenomena has been shaped by advances in theoretical understanding, the development of new techniques, and the characters of men. Large use has been made of quotations from many of the scientists involved. (Auth.)
International Nuclear Information System (INIS)
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
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.
Laser driven particle acceleration
International Nuclear Information System (INIS)
This dissertation summarizes the last ten years of research at the Laboratory of Applied Optics on laser-plasma based electron acceleration. The main result consists of the development and study of a relativistic electron source with unique properties: high energy (100-300 MeV) in short distances (few millimeters), mono-energetic, ultra-short (few fs), stable and tunable. The manuscript describes the steps that led to understanding the physics, and then mastering it in order to produce this new electron source. Non linear propagation of the laser pulse in the plasma is first presented, with phenomena such as non linear wakefield excitation, relativistic and ponderomotive self-focusing in the short pulse regime, self-compression. Acceleration and injection of electrons are then reviewed from a theoretical perspective. Experimental demonstrations of self-injection in the bubble regime and then colliding pulse injection are then presented. These experiments were among the first to produce monoenergetic, high quality, stable and tunable electron beams from a laser-plasma accelerator. The last two chapters are dedicated to the characterization of the electron beam using transition radiation and to its applications to gamma radiography and radiotherapy. Finally, the perspectives of this research are presented in the conclusion. Scaling laws are used to determine the parameters that the electron beams will reach using peta-watt laser systems currently under construction. (author)
Relativistic shocks and particle acceleration
International Nuclear Information System (INIS)
In this paper, we investigate the fluid dynamics of relativistic shock waves, and use the results to calculate the spectral index of particles accelerated by the Fermi process in such shocks. We have calculated the distributions of Fermi-accelerated particles at shocks propagating into cold proton-electron plasma and also cold electron-positron plasma. We have considered two different power spectra for the scattering waves, and find, in contrast to the non-relativistic case, that the spectral index of the accelerated particles depends on the wave power spectrum. On the assumption of thermal equilibrium both upstream and downstream, we present some useful fits for the compression ratio of shocks propagating at arbitrary speeds into gas of any temperature. (author)
Measuring momentum for charged particle tomography
Morris, Christopher; Fraser, Andrew Mcleod; Schultz, Larry Joe; Borozdin, Konstantin N.; Klimenko, Alexei Vasilievich; Sossong, Michael James; Blanpied, Gary
2010-11-23
Methods, apparatus and systems for detecting charged particles and obtaining tomography of a volume by measuring charged particles including measuring the momentum of a charged particle passing through a charged particle detector. Sets of position sensitive detectors measure scattering of the charged particle. The position sensitive detectors having sufficient mass to cause the charged particle passing through the position sensitive detectors to scatter in the position sensitive detectors. A controller can be adapted and arranged to receive scattering measurements of the charged particle from the charged particle detector, determine at least one trajectory of the charged particle from the measured scattering; and determine at least one momentum measurement of the charged particle from the at least one trajectory. The charged particle can be a cosmic ray-produced charged particle, such as a cosmic ray-produced muon. The position sensitive detectors can be drift cells, such as gas-filled drift tubes.
Zank, G. P.; Hunana, P.; Mostafavi, P.; le Roux, J. A.; Li, Gang; Webb, G. M.; Khabarova, O.
2015-09-01
As a consequence of the evolutionary conditions [28; 29], shock waves can generate high levels of downstream vortical turbulence. Simulations [32-34] and observations [30; 31] support the idea that downstream magnetic islands (also called plasmoids or flux ropes) result from the interaction of shocks with upstream turbulence. Zank et al. [18] speculated that a combination of diffusive shock acceleration (DSA) and downstream reconnection-related effects associated with the dynamical evolution of a “sea of magnetic islands” would result in the energization of charged particles. Here, we utilize the transport theory [18; 19] for charged particles propagating diffusively in a turbulent region filled with contracting and reconnecting plasmoids and small-scale current sheets to investigate a combined DSA and downstream multiple magnetic island charged particle acceleration mechanism. We consider separately the effects of the anti-reconnection electric field that is a consequence of magnetic island merging [17], and magnetic island contraction [14]. For the merging plasmoid reconnection- induced electric field only, we find i) that the particle spectrum is a power law in particle speed, flatter than that derived from conventional DSA theory, and ii) that the solution is constant downstream of the shock. For downstream plasmoid contraction only, we find that i) the accelerated particle spectrum is a power law in particle speed, flatter than that derived from conventional DSA theory; ii) for a given energy, the particle intensity peaks downstream of the shock, and the peak location occurs further downstream of the shock with increasing particle energy, and iii) the particle intensity amplification for a particular particle energy, f(x, c/c0)/f(0, c/c0), is not 1, as predicted by DSA theory, but increases with increasing particle energy. These predictions can be tested against observations of electrons and ions accelerated at interplanetary shocks and the heliospheric
Space charge tracking code for a synchrotron accelerator
Energy Technology Data Exchange (ETDEWEB)
Ottinger, M.B.; Tajima, T. [Univ. of Texas, Austin, TX (United States); Hiramoto, K. [Hitachi Ltd., Hitachi, Ibaraki (Japan). Hitachi Research Lab.
1997-06-01
An algorithm has been developed to compute particle tracking, including self-consistent space charge effects for synchrotron accelerators. In low-energy synchrotrons space charge plays a central role in enhancing emittance of the beam. The space charge effects are modeled by mutually interacting (through the Coulombic force) N cylindrical particles (2-{1/2}-dimensional dynamics) whose axis is in the direction of the equilibrium particle flow. On the other hand, their interaction with synchrotron lattice magnets is treated with the thin-lens approximation and in a fully 3-dimensional way. Since the existing method to treat space charge fully self-consistently involved 3-D space charge effect computation, the present method allows far more realistic physical parameters and runs in far shorter time (about 1/20). Some examples on space charge induced instabilities are presented.
Simultaneous acceleration of multiply charged ions through a superconducting linac
Ostroumov, P N; Zinkann, G P; Shepard, K W; Nolen, J A
2001-01-01
The possibility of simultaneously accelerating particles with a range of charge-to-mass ratios (~20%) to the same energy is proposed and demonstrated for a superconducting linac. Uranium ions stripped in a foil with eight charge states have been accelerated through a portion of the ATLAS linac from 286 to 690 MeV, with 94% of the injected uranium in the accelerated beam. Emittance of the resultant beam has been measured and the energy spread was 1.3% compared to 0.4% for a single charge state. This development has immediate application to the high-intensity acceleration of heavy ions that are limited by ion-source intensities, such as the proposed rare isotope accelerator facility. (6 refs).
Stabilization of electrostatic accelerator charging belt current
International Nuclear Information System (INIS)
For the purpose of improving reliability and quality of electrostatic accelerator basic parameters the stabilizer of charging belt current is developed. The stabilizer consists of two units: high-voltage unit and control unit. The charging rectifier assures voltage up to 60 kV at total current load of 750 μA. For the EG- 2.5 and the EGP-10 M accelerators supply circuits of charging device with an earth screen and posAitive voltage supply the needles. t the EGP-10-1 accelerator negative charging voltage is supplied to the screens of the charging device. ''Plus'' of the rectifier is earthed. Charging and recharging are performed by means of brushes slipping over the internal belt side. At all accelerators the stability of charging current mean value is not worse 0.1%. The highest response of the system are obtained at the EG-2.5 accelerator for account of rectifier load by charging current and instrument resistor from 140 to 400 MOhm
International Nuclear Information System (INIS)
Advanced target designs require thicker (approx. 300 μm) coatings and better surface finishes that can be produced with current coating techniques. An advanced coating technique is proposed to provide maximum control of the coating flux and optimum manipulation of the shell during processing. In this scheme a small beam of ions or particles of known incident energy are collided with a levitated spherical mandrel. Precise control of the incident energy and angle of the deposition flux optimizes the control of the coating morphology while controlled rotation and noncontact support of the shell minimizes the possibility of particulate or damage generated defects. Almost infinite variability of the incident energy and material in this process provides increased flexibility of the target designs which can be physically realized
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.
Precise Charge Measurement For Laser Plasma Accelerators
International Nuclear Information System (INIS)
Cross-calibrations of charge diagnostics are conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). Employed diagnostics are a scintillating screen, activation based measurement, and integrating current transformer. The diagnostics agreed within ±8 %, showing that they can provide accurate charge measurements for LPAs provided they are used properly.
Minimization of power consumption during charging of superconducting accelerating cavities
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.
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.
International Nuclear Information System (INIS)
Recent investigations indicate that sufficiently long beams of charged particles, travelling in a plasma, experience the phenomenon of self-modulation. The self-modulation is driven by the plasma wake field excitation due to the beam itself, and it may become unstable under certain conditions. A preliminary theoretical investigation of the self-modulation of a relativistic charged-particle beam in overdense plasma in the presence of a preformed plasma wave is carried out, within the quantum-like description of charged particle beams provided by the Thermal Wave Model. A simple physical model for the self-modulation is put forward, described by a nonlinear Schrödinger equation coupled with the Poisson-like equation for the plasma wake potential (so-called Fedele–Shukla equations). The physical mechanism is based on the interplay of three concomitant effects, the radial thermal dispersion (associated with the emittance ε), the radial ponderomotive effects of a preexisting plasma wave (which provides the guidance for the beam), and the self-interaction of the plasma wake field generated by the beam itself
Magnetic guidance of charged particles
Dubbers, Dirk
2015-01-01
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 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, for instance in neutrino mass retardation spectrometers.
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.
Charge Diagnostics for Laser Plasma Accelerators
International Nuclear Information System (INIS)
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.
Illusory Flow in Radiation from Accelerating Charge
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.
Geometrical charged-particle optics
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...
Heavy charged particle radiotherapy trial
International Nuclear Information System (INIS)
Through mid-1985, a total of 49 patients received heavy-charged-particle irradiation for chordoma, chondrosarcoma, meningioma, or neurilemmoma of the base of skull or juxtaspinal area. The mean tumor dose was 68 Gray-equivalent, ranging from 26 to 80. Control within the irradiated area was obtained in 35 of 49. The median follow up in all 49 patients is 21 months, with a range from 3-90 months. Serious complications were seen in a small number of patients, with cranial nerve injury in two, transverse myelitis in one, and brain necrosis in three patients. In 42 patients with tumors of other histologies and/or sites, including tumors of paranasal sinuses, retroperitoneum, soft tissue and miscellaneous other sites, heavy charged particles were also used to deliver a higher tumor dose than possible with standard irradiation techniques. In the group, 21/42 (50%) have had local tumor control, also a good result considering the extent and the range of tumor types treated. The authors believe that there are a number of sites in addition to the juxtaspinal/base of skull tumors that will show long term benefit from treatment with heavy charged particles
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...... point of demand tracer production with very small cyclotrons of energy well below 10 MeV. The authors best advice at present for new PET sites is to negotiate for conventional cyclotron solutions from experienced manufacturers. It is the combined performance of cyclotron and target in terms of available...
Theory and design of charged particle beams
Reiser, Martin
1994-01-01
Although particle accelerators are the book's main thrust, it offers a broad synoptic description of beams which applies to a wide range of other devices such as low-energy focusing and transport systems and high-power microwave sources. Develops material from first principles, basic equations and theorems in a systematic way. Assumptions and approximations are clearly indicated. Discusses underlying physics and validity of theoretical relationships, design formulas and scaling laws. Features a significant amount of recent work including image effects and the Boltzmann line charge density prof
Direct charged particle imaging sensors
International Nuclear Information System (INIS)
CMOS image sensors optimized for charged particle imaging applications, such as electron microscopy and particle physics, have been designed and characterized. These directly image charged particles without reliance on performance-degrading hybrid technologies such as the use of scintillating materials. Based on standard CMOS active pixel sensor (APS) technology, the sensor arrays uses an 8-20 μm epitaxial layer that acts as a thicker sensitive region for the generation and collection of ionization electrons resulting from impinging high-energy particles. This results in a 100% fill factor and a far larger signal per incident electron than a standard CMOS photodiode could provide. A 512x550 pixels prototype has been fabricated and used extensively in an electron microscope, including having been used to take sample images. Temporal noise was measured to be 0.9 mV RMS, and the dynamic range was 60 dB. Power consumption at 70 frames/s is 20 mW. The full-width half-maximum of the collected ionization electron distribution was found to be 5.5 μm, yielding a spatial resolution of approximately 2.3 μm for individual incident electrons, and the modulation transfer function of the sensor at the Nyquist limit is to be 32%
The dynamics of a charged particle
Rohrlich, Fritz
2008-01-01
Using physical arguments, I derive the physically correct equations of motion for a classical charged particle from the Lorentz-Abraham-Dirac equations (LAD) which are well known to be physically incorrect. Since a charged particle can classically not be a point particle because of the Coulomb field divergence, my derivation accounts for that by imposing a basic condition on the external force. That condition ensures that the particle's finite size charge distribution looks like a point charg...
Accelerator Technology: Geodesy and Alignment for Particle Accelerators
Missiaen, D
2013-01-01
This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the the Section '8.9 Geodesy and Alignment for Particle Accelerators' of the Chapter '8 Accelerator Technology' with the content: 8.9 Geodesy and Alignment for Particle Accelerators 8.9.1 Introduction 8.9.2 Reference and Co-ordinate Systems 8.9.3 Definition of the Beam Line on the Accelerator Site 8.9.4 Geodetic Network 8.9.5 Tunnel Preliminary Works 8.9.6 The Alignment References 8.9.7 Alignment of Accelerator Components 8.9.8 Permanent Monitoring and Remote Alignment of Low Beta Quadrupoles 8.9.9 Alignment of Detector Components
Conceptual and technological evolutions of particle accelerators
Institute of Scientific and Technical Information of China (English)
Lee C.Teng
2009-01-01
We give here an ordered list of all types of particle accelerators and exhibit how each type evolves conceptually and/or technologically from the preceding.This is in contrast to the usual "history of particle accelerators" in which unrelated accelerator types are listed in the chronological order.It is hoped that this discussion and understanding of the rationale and logic in the evolution of one accelerator type to the next will help to educe future inventions.
Heavy-ion radiography applied to charged particle radiotherapy
International Nuclear Information System (INIS)
The objectives of the heavy-ion radiography research program applied to the clinical cancer research program of charged particle radiotherapy have a twofold purpose: (1) to explore the manner in which heavy-ion radiography and CT reconstruction can provide improved tumor localization, treatment planning, and beam delivery for radiotherapy with accelerated heavy charged particles; and (2) to explore the usefulness of heavy-ion radiography in detecting, localizing, and sizing soft tissue cancers in the human body. The techniques and procedures developed for heavy-ion radiography should prove successful in support of charged particle radiotherapy
Neural computation and particle accelerators research, technology and applications
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 ...
Particle acceleration at a reconnecting magnetic separator
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 ...
High frequency single mode traveling wave structure for particle acceleration
Ivanyan, M. I.; Danielyan, V. A.; Grigoryan, B. A.; Grigoryan, A. H.; Tsakanian, A. V.; Tsakanov, V. M.; Vardanyan, A. S.; Zakaryan, S. V.
2016-09-01
The development of the new high frequency slow traveling wave structures is one of the promising directions in accomplishment of charged particles high acceleration gradient. The disc and dielectric loaded structures are the most known structures with slowly propagating modes. In this paper a large aperture high frequency metallic two-layer accelerating structure is studied. The electrodynamical properties of the slowly propagating TM01 mode in a metallic tube with internally coated low conductive thin layer are examined.
Charge of dust particles in a particle chain
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.
Double layers are not particle accelerators
International Nuclear Information System (INIS)
It is pointed out that the continuing advocacy of electrostatic double layers as particle accelerators in the aurora and other space and astrophysical plasmas is fundamentally unsound. It is suggested furthermore that there is little reason to invoke static or quasi-static electric fields as the cause of auroral electron acceleration. Stochastic acceleration by electrostatic wave turbulence appears to present a natural explanation for this and for electron acceleration in other space and astrophysical plasmas. (author)
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.
Charged particle beam scanning using deformed high gradient insulator
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.
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)
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.).
All-optical trapping and acceleration of heavy particles
Peano, F; Silva, L O; Mulas, R; Coppa, G
2008-01-01
A scheme for fast, compact, and controllable acceleration of heavy particles in vacuum is proposed, in which two counterpropagating lasers with variable frequencies drive a beat-wave structure with variable phase velocity, thus allowing for trapping and acceleration of heavy particles, such as ions or muons. Fine control over the energy distribution and the total charge of the beam is obtained via tuning of the frequency variation. The acceleration scheme is described with a one-dimensional theory, providing the general conditions for trapping and scaling laws for the relevant features of the particle beam. Two-dimensional, electromagnetic particle-in-cell simulations confirm the validity and the robustness of the physical mechanism.
CAS CERN Accelerator School superconductivity in particle accelerators
International Nuclear Information System (INIS)
One of the objectives of the CERN Accelerator School is to run courses on specialised topics in the particle accelerator field. The present volume contains the proceedings of one such course, this time organized in conjunction with the Deutsches Elektronen Synchrotron (DESY) on the subject of superconductivity in particle accelerators. This course reflects the very considerable progress made over the last few years in the use of the technology for the magnet and radio-frequency systems of many large and small accelerators already in use or nearing completion, while also taking account of the development work now going on for future machines. The lectures cover the theory of superconductivity, cryogenics and accelerator magnets and cavities, while the seminars include superfluidity, superconductors, special magnets and the prospects for high-temperature superconductors. (orig.)
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.)
Acceleration and Particle Field Interactions of Cosmic Rays I: Formalism
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.
New mechanism of acceleration of particles by stellar black holes
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.
Delay Equation for Charged Brown Particle
Vlasov, Alexander A.
2001-01-01
In previous work (physics/0004026) was shown, with the help of numerical calculations, that the effective Brown temperature for charged particle is lower than that for particle without charge. Here we derive this result without numerical calculations, integrating the delay equation analytically, as for zero, so for nonzero viscosity.
Global particle accelerator gets the big chill
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)
Lauch of CERN particle accelerator delayed
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)
Visions for the future of particle accelerators
Romaniuk, Ryszard S.
2013-10-01
The ambitions of accelerator based science, technology and applications far exceed the present accelerator possibilities. Accelerator science and technology is one of a key enablers of the developments in the particle physic, photon physics and also applications in medicine and industry. The paper presents a digest of the research results and visions for the future in the domain of accelerator science and technology in Europe, shown during the final fourth annual meeting of the EuCARD - European Coordination of Accelerator Research and Development. The conference concerns building of the research infrastructure, including advanced photonic and electronic systems for servicing large high energy physics experiments. There are debated a few basic groups of such systems like: measurement - control networks of large geometrical extent, multichannel systems for large amounts of metrological data acquisition, precision photonic networks of reference time, frequency and phase distribution. The main subject is however the vision for the future of particle accelerators and next generation light sources.
Particle acceleration in the plasma fields near comet Halley
International Nuclear Information System (INIS)
Spacecraft VEGA-1 approached Halley comet to distances less than 10 million km in March 1986. It was equipped with devices capable to detect and measure the energies of charged particles (higher than 50 keV). After a survey of acceleration mechanisms the properties of the 50-800 keV charged particle fluxes observed in various regions around Halley comet are reported. In particular, the regions outside the cometary bow shock, the region between the bow shock and the cometopause, and inside the latter, especially in the magnetic pile-up region are considered. Possible mechanisms responsible for the accelerations of the particle fluxes described are discussed. (author) 73 refs.; 7 figs.; 3 tabs
Scintillation Detectors for Charged Particles and Photons
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...
Particle acceleration at reconnecting separator current layers
Threlfall, J.; E. H. Stevenson, J.; E. Parnell, C.; Neukirch, T.
2015-01-01
The aim of this work is to investigate and characterise particle behaviour in a 3D magnetohydrodynamic (MHD) model of a reconnecting magnetic separator. We use a relativistic guiding-centre test-particle code to investigate electron and proton acceleration in snapshots from 3D MHD separator reconnection experiments, and compare the results with findings from an analytical separator reconnection model studied in a previous investigation. The behaviour and acceleration of large distributions of...
Geometric integration for particle accelerators
International Nuclear Information System (INIS)
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
Charged-particle activation analysis
International Nuclear Information System (INIS)
The paper discusses the methodology and application of nuclear activation with ion beams (19 via 16O(3He,p)18F, 12C(3He,α)11C and 14N(p,α)11C respectively. Recently, triton activation has been shown to be inherently still superior to 3He activation for the determination of oxygen [16O(3H,n)18F]. Lithium, boron, carbon and sulphur can be detected rapidly, nondestructively and with high sensitivity (approximately 0.25ppm for Li and B) via ''quasi-prompt'' activation based on the detection of short-lived, high-energy beta emitters (10ms1H(7Li,n)7Be for example. Nondestructive multielement analysis: Proton activation has the inherent potential for meeting requirements of broad elemental coverage, sensitivity (ppm and sub-ppm range) and selectivity. Up to 30 elements have been determined in Al, Co, Ag, Nb, Rh, Ta and biological samples, using 12-MeV proton activation followed by gamma-ray spectrometry. These capabilities are further enhanced with the counting of X-ray emitters, 28 elements (269) and accuracy using proton activation. 204Pb/206Pb ratios can also be determined with a relative precision of a few per cent. Although charged-particle activation analysis is a well-established trace analysis technique, broad potential capabilities remain to be explored, e.g. those arising from ultrashort-lived nuclides, heavy ion interactions and the combination of delayed and prompt methods. (author)
Charge Exchange Losses and Stochastic Acceleration in the Solar Wind
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...
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
Radiation Reaction for a Charged Brownian Particle
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.
Particle Acceleration by a Solar Flare Termination Shock
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.
Electroweak interaction of particles with accelerated matter and astrophysical applications
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...
Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams
Schroeder, C. B.
2011-01-01
Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.
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.
Stochastic Particle Acceleration in Blazar Jets
Institute of Scientific and Technical Information of China (English)
无
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.
Laser ion source for particle accelerators
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.
Particle acceleration by shocks in supernova remnants
Bell, A R
2013-01-01
Particle acceleration occurs on a range of scales from AU in the heliosphere to Mpc in clusters of galaxies and to energies ranging from MeV to EeV. A number of acceleration processes have been proposed, but diffusive shock acceleration (DSA) is widely invoked as the predominant mechanism. DSA operates on all these scales and probably to the highest energies. DSA is simple, robust and predicts a universal spectrum. However there are still many unknowns regarding particle acceleration. This paper focuses on the particular question of whether supernova remnants (SNR) can produce the Galactic CR spectrum up to the knee at a few PeV. The answer depends in large part on the detailed physics of diffusive shock acceleration.
Particle Acceleration in Dissipative Pulsar Magnetospheres
Kazanas, Z.; Kalapotharakos, C.; Harding, A.; Contopoulos, I.
2012-01-01
Pulsar magnetospheres represent unipolar inductor-type electrical circuits at which an EM potential across the polar cap (due to the rotation of their magnetic field) drives currents that run in and out of the polar cap and close at infinity. An estimate ofthe magnitude of this current can be obtained by dividing the potential induced across the polar cap V approx = B(sub O) R(sub O)(Omega R(sub O)/c)(exp 2) by the impedance of free space Z approx eq 4 pi/c; the resulting polar cap current density is close to $n {GJ} c$ where $n_{GJ}$ is the Goldreich-Julian (GJ) charge density. This argument suggests that even at current densities close to the GJ one, pulsar magnetospheres have a significant component of electric field $E_{parallel}$, parallel to the magnetic field, a condition necessary for particle acceleration and the production of radiation. We present the magnetic and electric field structures as well as the currents, charge densities, spin down rates and potential drops along the magnetic field lines of pulsar magnetospheres which do not obey the ideal MHD condition $E cdot B = 0$. By relating the current density along the poloidal field lines to the parallel electric field via a kind of Ohm's law $J = sigma E_{parallel}$ we study the structure of these magnetospheres as a function of the conductivity $sigma$. We find that for $sigma gg OmegaS the solution tends to the (ideal) Force-Free one and to the Vacuum one for $sigma 11 OmegaS. Finally, we present dissipative magnetospheric solutions with spatially variable $sigma$ that supports various microphysical properties and are compatible with the observations.
Massive particle accelerator revving up
Kestenbaum, David S
2007-01-01
"This summer, physicists plan to throww the switch on what is arguably the largest and most complex science experiment ever conducted. An underground ring of superconducting magnets, reaching from Switzerland into France, will smash together subatomic particles at incredible force." (3 pages)
Simulation of non-charged particles
International Nuclear Information System (INIS)
This paper presents the method used to simulate the transport of neutral particles by using a Monte Carlo method with accelerating techniques of convergence based on the importance function by the method of first collision probabilities
Trapped charged particles a graduate textbook with problems and solutions
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 ...
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.
Non-accelerator particle physics
International Nuclear Information System (INIS)
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 m2sr, 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
Educational applications on particle accelerators in Brazil
International Nuclear Information System (INIS)
The Brazilian production of radiopharmaceuticals and radioisotopes for medical usage dates back to the 70's, since the beginning up to 2006; it was a monopoly of the government-owned corporations. After the market was open for the private enterprise, the quantity of small particle accelerators is increasing. The difficulties are many, from industry installation to the hard time on finding qualified personnel. The lack of investment on this area brought few trained people and the trained ones keep working in the government laboratories. Facing this issue, a strong program was started on training and educating people on universities, businesses enterprises and at hospitals in order to increase the human resources capabilities in the country. Activities such as laboratory research and lectures are being made as well in order to adapt Brazil to the renascence of the nuclear technology and increase the knowledge in the field of particle accelerators. These investments on education are preparing professionals in several areas, such as: physics, engineering, pharmacy, medicine, administration, among others. It started on the universities not only with lectures and workshops, but also with research partnerships on the stand-by time of the particle accelerators. At clinics and hospitals the efforts are focused in the improvement and training of the particle accelerator product applications. One of the private enterprise corporations has trained more than 30 people from five different states and established partnership with five different universities, qualifying people on installation, operation, maintenance and administration of the whole process of implementation of a particle accelerator site. It's also collaborating with the universities and researchers in the development of new techniques: the irradiation of other material targets or the use of non-usual particle beams, allowing the study of the nuclear activation of the concrete walls of the particle accelerator
Electromagnetic fields and potentials generated by massless charged particles
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...
Observation of particle acceleration in laboratory magnetosphere
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.
Robust statistical reconstruction for charged particle tomography
Schultz, Larry Joe; Klimenko, Alexei Vasilievich; Fraser, Andrew Mcleod; Morris, Christopher; Orum, John Christopher; Borozdin, Konstantin N; Sossong, Michael James; Hengartner, Nicolas W
2013-10-08
Systems and methods for charged particle detection including statistical reconstruction of object volume scattering density profiles from charged particle tomographic data to determine the probability distribution of charged particle scattering using a statistical multiple scattering model and determine a substantially maximum likelihood estimate of object volume scattering density using expectation maximization (ML/EM) algorithm to reconstruct the object volume scattering density. The presence of and/or type of object occupying the volume of interest can be identified from the reconstructed volume scattering density profile. The charged particle tomographic data can be cosmic ray muon tomographic data from a muon tracker for scanning packages, containers, vehicles or cargo. The method can be implemented using a computer program which is executable on a computer.
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.
New Charged Particles from Higgs Couplings
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.
Recent trends in particle accelerator radiation safety
International Nuclear Information System (INIS)
The use of particle accelerators in applied and research activities continues to expand, bringing new machines with higher energy and current capabilities which create radiation safety problems not commonly encountered before. An overview is given of these increased ionizing radiation hazards, along with a discussion of some of the new techniques required in evaluating and controlling them. A computer search of the literature provided a relatively comprehensive list of publications describing accelerator radiation safety problems and related subjects
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.
Diffusive Acceleration of Particles at Oblique, Relativistic, Magnetohydrodynamic Shocks
Summerlin, Errol J
2011-01-01
Diffusive shock acceleration (DSA) at relativistic shocks is expected to be an important acceleration mechanism in a variety of astrophysical objects including extragalactic jets in active galactic nuclei and gamma ray bursts. These sources remain good candidate sites for the generation of ultra-high energy cosmic rays. In this paper, key predictions of DSA at relativistic shocks that are germane to production of relativistic electrons and ions are outlined. The technique employed to identify these characteristics is a Monte Carlo simulation of such diffusive acceleration in test-particle, relativistic, oblique, magnetohydrodynamic (MHD) shocks. Using a compact prescription for diffusion of charges in MHD turbulence, this approach generates particle angular and momentum distributions at any position upstream or downstream of the shock. Simulation output is presented for both small angle and large angle scattering scenarios, and a variety of shock obliquities including superluminal regimes when the de Hoffmann...
Kerr Naked Singularities as Particle Accelerators
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.
Acceleration-extended Galilean symmetries with central charges and their dynamical realizations
Energy Technology Data Exchange (ETDEWEB)
Lukierski, J. [Institute for Theoretical Physics, University of Wroclaw, pl. Maxa Borna 9, 50-205 Wroclaw (Poland)]. E-mail: lukier@ift.uni.wroc.pl; Stichel, P.C. [An der Krebskuhle 21, D-33619 Bielefeld (Germany)]. E-mail: peter@physik.uni-bielefeld.de; Zakrzewski, W.J. [Department of Mathematical Sciences, University of Durham, Durham DH1 3LE (United Kingdom)]. E-mail: W.J.Zakrzewski@durham.ac.uk
2007-06-28
We add to Galilean symmetries the transformations describing constant accelerations. The corresponding extended Galilean algebra allows, in any dimension D=d+1, the introduction of one central charge c while in D=2+1 we can have three such charges: c,{theta} and {theta}{sup '}. We present nonrelativistic classical mechanics models, with higher order time derivatives and show that they give dynamical realizations of our algebras. The presence of central charge c requires the acceleration square Lagrangian term. We show that the general Lagrangian with three central charges can be reinterpreted as describing an exotic planar particle coupled to a dynamical electric and a constant magnetic field.
Acceleration-Extended Galilean Symmetries with Central Charges and their Dynamical Realizations
Lukierski, J; Zakrzewski, W J
2007-01-01
We add to Galilean symmetries the transformations describing constant accelerations. The corresponding extended Galilean algebra allows, in any dimension $D=d+1$, the introduction of one central charge $c$ while in $D=2+1$ we can have three such charges: c, \\theta and \\theta'. We present nonrelativistic classical mechanics models, with higher order time derivatives and show that they give dynamical realizations of our algebras. The presence of central charge $c$ requires the acceleration square Lagrangian term. We show that the general Lagrangian with three central charges can be reinterpreted as describing an exotic planar particle coupled to a dynamical electric and a constant magnetic field.
Acceleration-extended Galilean symmetries with central charges and their dynamical realizations
International Nuclear Information System (INIS)
We add to Galilean symmetries the transformations describing constant accelerations. The corresponding extended Galilean algebra allows, in any dimension D=d+1, the introduction of one central charge c while in D=2+1 we can have three such charges: c,θ and θ'. We present nonrelativistic classical mechanics models, with higher order time derivatives and show that they give dynamical realizations of our algebras. The presence of central charge c requires the acceleration square Lagrangian term. We show that the general Lagrangian with three central charges can be reinterpreted as describing an exotic planar particle coupled to a dynamical electric and a constant magnetic field
A particle accelerator probes artifacts
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...
Directory of Open Access Journals (Sweden)
M. V. Rodrigues
2006-03-01
Full Text Available This work gives sequence to the study on the measurement of the electrostatic charges in aerosols. The particle charge classifier developed for this purpose and presented in the previous paper (Marra and Coury, 2000 has been used here to measure the particle charge distribution of a number of different aerosols. The charges acquired by the particles were naturally derived from the aerosol generation procedure itself. Two types of aerosol generators were used: the vibrating orifice generator and turntable Venturi plate generator. In the vibrating orifice generator, mono-dispersed particles were generated by a solution of water/ethanol/methylene blue, while in the rotating plate generator, six different materials were utilized. The results showed no clear dependence between electric charge and particle diameter for the mono-dispersed aerosol. However, for the poly-dispersed aerosols, a linear dependence between particle size and charge could be noticed.
Hybrid Simulations of Particle Acceleration at Shocks
Energy Technology Data Exchange (ETDEWEB)
Caprioli, Damiano
2014-11-15
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.
Charged-particle beam: a safety mandate
International Nuclear Information System (INIS)
The Advanced Test Accelerator (ATA) is a recent development in the field of charged particle beam research at Lawrence Livermore National Laboratory. With this experimental apparatus, researchers will characterize intense pulses of electron beams propagated through air. Inherent with the ATA concept was the potential for exposure to hazards, such as high radiation levels and hostile breathing atmospheres. The need for a comprehensive safety program was mandated; a formal system safety program was implemented during the project's conceptual phase. A project staff position was created for a safety analyst who would act as a liaison between the project staff and the safety department. Additionally, the safety analyst would be responsible for compiling various hazards analyses reports, which formed the basis of th project's Safety Analysis Report. Recommendations for safety features from the hazards analysis reports were incorporated as necessary at appropriate phases in project development rather than adding features afterwards. The safety program established for the ATA project faciliated in controlling losses and in achieving a low-level of acceptable risk
Charged Particle Monitor on the AstroSat mission
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.
Particles with non abelian charges
Bastianelli, Fiorenzo; Corradini, Olindo; Latini, Emanuele
2013-01-01
Efficient methods for describing non abelian charges in worldline approaches to QFT are useful to simplify calculations and address structural properties, as for example color/kinematics relations. Here we analyze in detail a method for treating arbitrary non abelian charges. We use Grassmann variables to take into account color degrees of freedom, which however are known to produce reducible representations of the color group. Then we couple them to a U(1) gauge field defined on the worldline, together with a Chern-Simons term, to achieve projection on an irreducible representation. Upon gauge fixing there remains a modulus, an angle parametrizing the U(1) Wilson loop, whose dependence is taken into account exactly in the propagator of the Grassmann variables. We test the method in simple examples, the scalar and spin 1/2 contribution to the gluon self energy, and suggest that it might simplify the analysis of more involved amplitudes.
Discrete Element Modeling of Triboelectrically Charged Particles
Hogue, Michael D.; Calle, Carlos I.; Weitzman, Peter S.; Curry, David R.
2008-01-01
Tribocharging of particles is common in many processes including fine powder handling and mixing, printer toner transport and dust extraction. In a lunar environment with its high vacuum and lack of water, electrostatic forces are an important factor to consider when designing and operating equipment. Dust mitigation and management is critical to safe and predictable performance of people and equipment. The extreme nature of lunar conditions makes it difficult and costly to carry out experiments on earth which are necessary to better understand how particles gather and transfer charge between each other and with equipment surfaces. DEM (Discrete Element Modeling) provides an excellent virtual laboratory for studying tribocharging of particles as well as for design of devices for dust mitigation and for other purposes related to handling and processing of lunar regolith. Theoretical and experimental work has been performed pursuant to incorporating screened Coulombic electrostatic forces into EDEM, a commercial DEM software package. The DEM software is used to model the trajectories of large numbers of particles for industrial particulate handling and processing applications and can be coupled with other solvers and numerical models to calculate particle interaction with surrounding media and force fields. While simple Coulombic force between two particles is well understood, its operation in an ensemble of particles is more complex. When the tribocharging of particles and surfaces due to frictional contact is also considered, it is necessary to consider longer range of interaction of particles in response to electrostatic charging. The standard DEM algorithm accounts for particle mechanical properties and inertia as a function of particle shape and mass. If fluid drag is neglected, then particle dynamics are governed by contact between particles, between particles and equipment surfaces and gravity forces. Consideration of particle charge and any tribocharging and
Fractionally charged particles in cosmic rays
Bashindzhagyan, George
2016-01-01
The results of many experiments on a search of fractionally charged particles in cosmic rays have been reviewed. The registered by ATIC and PAMELA experiments change of the proton energy spectrum at about 250 GeV can be explained if fractionally charged particles with another energy spectrum slope actually mixed with protons but cannot be separated because of a strong dE/dx fluctuations. The performed simulations show that multilayer detectors can seriously help in such separation. In the Aragats experiment performed using multilayer proportional counter combined with hadron calorimeter a group of 4e/3 like events with unexpectedly high average energy has been registered. It could be explained by their different from regular hadrons energy spectrum. The ATIC experiment ionization spectrum in single charged particle area has been examined. An interesting bump in 2e/3 charge region was observed. The events in the bump have very different from regular protons angular distribution.
Electro-optical detection of charged particles
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.
Fermions tunneling from charged accelerating and rotating black holes with NUT parameter
Energy Technology Data Exchange (ETDEWEB)
Sharif, M.; Javed, Wajiha [University of the Punjab, Quaid-e-Azam Campus, Department of Mathematics, Lahore (Pakistan)
2012-05-15
This paper is devoted to the study of Hawking radiation as a tunneling of charged fermions through event horizons of a pair of charged accelerating and rotating black holes with NUT parameter. We evaluate tunneling probabilities of outgoing charged particles by using the semiclassical WKB approximation to the general covariant Dirac equation. The Hawking temperature corresponding to this pair of black holes is also investigated. For the zero NUT parameter, we find results consistent with those already available in the literature. (orig.)
New developments in particle acceleration techniques. Proceedings. Vol. 1
International Nuclear Information System (INIS)
A Workshop organised jointly by the European Committee for Future Accelerators (ECFA), the CERN Accelerator School (CAS), the Institut National de Physique Nucleaire et de Physique des Particules (IN2P3), the Institut pour la Recherche Fondamentale/Commissariat a l'Energie Atomique (IRF/CEA) and the European Physical Society (EPS) was held at the Laboratoire de l'Accelerateur Lineaire (LAL), Orsay, from 29 June to 4 July 1987. Its purpose was to review current experimental and theoretical developments in charged-particle accelerator techniques and to address problems related to future very-high-energy machines. These proceedings contain the great majority of the papers presented at the Workshop, the corresponding questions and answers, and the round-table discussion. The principal topics were semi-conventional high-frequency linacs, transformer acceleration mechanisms, acceleration using plasma, e+e- sources including low-emittance production and preservation, final focus and interaction point, and other new ideas. Among the latter were open accelerating structures, crystal X-ray accelerators, ferroelectrics, and acceleration using lasers. (orig.)
New developments in particle acceleration techniques. Proceedings. Vol. 2
International Nuclear Information System (INIS)
A Workshop organised jointly by the European Committee for Future Accelerators (ECFA), the CERN Accelerator School (CAS), the Institut National de Physique Nucleaire et de Physique des Particules (IN2P3), the Institut pour la Recherche Fondamentale/Commissariat a l'Energie Atomique (IRF/CEA) and the European Physical Society (EPS) was held at the Laboratoire de l'Accelerateur Lineaire (LAL), Orsay, from 29 June to 4 July 1987. Its purpose was to review current experimental and theoretical developments in charged-particle accelerator techniques and to address problems related to future very-high-energy machines. These proceedings contain the great majority of the papers presented at the Workshop, the corresponding questions and answers, and the round-table discussion. The principal topics were semi-conventional high-frequency linacs, transformer acceleration mechanisms, acceleration using plasma, e+e- sources, including low-emittance production and preservation, final focus and interaction point, and other new ideas. Among the latter were open accelerating structures, crystal X-ray accelerators, ferroelectrics, and acceleration using lasers. (orig.)
Particle acceleration via reconnection processes in the supersonic solar wind
Energy Technology Data Exchange (ETDEWEB)
Zank, G. P.; Le Roux, J. A.; Webb, G. M.; Dosch, A. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Khabarova, O. [Heliophysical Laboratory, Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation RAS (IZMIRAN), Troitsk, Moscow 142190 (Russian Federation)
2014-12-10
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. 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 derive a gyrophase-averaged transport equation for particles experiencing pitch-angle scattering and energization in a super-Alfvénic flowing plasma experiencing multiple small-scale reconnection events. A simpler advection-diffusion transport equation for a nearly isotropic particle distribution is derived. The dominant charged particle energization processes are (1) the electric field induced by quasi-2D magnetic island merging and (2) magnetic island contraction. The magnetic island topology ensures that charged particles are trapped in regions where they experience repeated interactions with the induced electric field or contracting magnetic islands. Steady-state solutions of the isotropic transport equation with only the induced electric field and a fixed source yield a power-law spectrum for the accelerated particles with index α = –(3 + M{sub A} )/2, where M{sub A} is the Alfvén Mach number. Considering only magnetic island contraction yields power-law-like solutions with index –3(1 + τ {sub c}/(8τ{sub diff})), where τ {sub c}/τ{sub diff} is the ratio of timescales between magnetic island contraction and charged particle diffusion. The general solution is a power-law-like solution with an index that depends on the Alfvén Mach number and the timescale ratio τ{sub diff}/τ {sub c}. Observed power-law distributions of energetic particles observed in the quiet supersonic solar wind at 1 AU may be a consequence of particle acceleration associated with dissipative small-scale reconnection processes in a turbulent plasma, including the widely reported c {sup –5} (c particle
Why do particle clouds generate electric charges?
Pähtz, T.; Herrmann, H. J.; Shinbrot, T.
2010-05-01
Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, because it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. Here, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains in the presence of an electric field, and we confirm the model's predictions using discrete-element simulations and a tabletop granular experiment.
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}.
AXEL-2016: Introduction to Particle Accelerators
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...
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.
The prospects for charged particle uses in oncology
International Nuclear Information System (INIS)
Prospects and problems of proton therapy by means of accelerators are considered. Approaches to the solution of the problems concerning operation modes of the accelerator are formulated. It is shown that despite vivid advantage of charged particles for their applied use in beam therapy of malignant tumour it is necessary to solve two problems: extraction of special beams meeting strict medical requirements and development of technology of irradiation of malignant tumours of different localizations and construction of special equipment for execution of this technology. Engineering-technological shortcomings of proton therapy and medical-biological problems requiring reglamentation are enumerated
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.
Power Supplies for High Energy Particle Accelerators
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.
A threshold for laser-driven linear particle acceleration in unbounded vacuum
Wong, L. J.; Kärtner, F. X.
2011-01-01
We hypothesize that a charged particle in unbounded vacuum can be substantially accelerated by a force linear in the electric field of a propagating electromagnetic wave only if the accelerating field is capable of bringing the particle to a relativistic energy in its initial rest frame during the interaction. We consequently derive a general formula for the acceleration threshold of such schemes and support our conclusion with the results of numerical simulations over a broad range of parame...
Bibliography of integral charged particle nuclear data
International Nuclear Information System (INIS)
This publication is the second supplement to the archival edition of the National Nuclear Data Center's charged-particle bibliography. This supplement contains citations to all references scanned since March 15, 1981, and all corrections and additions to previous citations, and indexes all data received in the international exchanged format (EXFOR). The primary goal of the bibliography has been to satisfy the need expressed by the Nuclear Reaction Data Center Network for a concise and comprehensive bibliography of integral charged-particle cross section data and to provide an index of data exchanged among the members. In 1980, coverage was expanded to include differential data relevant to charged-particle-induced neutron-source reactions
Coulomb field of an accelerated charge physical and mathematical aspects
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.
CAS CERN Accelerator School: Power converters for particle accelerators
International Nuclear Information System (INIS)
This volume presents the proceedings of the fifth specialized course organized by the CERN Accelerator School, the subject on this occasion being power converters for particle accelerators. The course started with lectures on the classification and topologies of converters and on the guidelines for achieving high performance. It then went on to cover the more detailed aspects of feedback theory, simulation, measurements, components, remote control, fault diagnosis and equipment protection as well as systems and grid-related problems. The important topics of converter specification, procurement contract management and the likely future developments in semiconductor components were also covered. Although the course was principally directed towards DC and slow-pulsed supplies, lectures were added on fast converters and resonant excitation. Finally the programme was rounded off with three seminars on the related fields of Tokamak converters, battery energy storage for electric vehicles, and the control of shaft generators in ships. (orig.)
Particle Acceleration and Heating by Turbulent Reconnection
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...
An End-to-End Test of Neutron Stars as Particle Accelerators
CARAVEO, PATRIZIA A.
2005-01-01
Combining resolved spectroscopy with deep imaging, XMM-Newton is providing new insights on the particle acceleration processes long known to be at work in the magnetospheres of isolated neutron stars. According to a standard theoretical interpretation, in neutron stars' magnetospheres particles are accelerated along the B field lines and, depending on their charge, they can either move outward, to propagate in space, or be funnelled back, towards the star surface. While particles impinging on...
Particle Acceleration at Multiple Internal Relativistic Shocks
Dempsey, P; Dempsey, Paul; Duffy, Peter
2006-01-01
Relativistic shocks provide an efficient method for high-energy particle acceleration in many astrophysical sources. Multiple shock systems are even more effective and of importance, for example, in the internal shock model of gamma-ray bursts. We investigate the reacceleration of pre-existing energetic particles at such relativistic internal shocks by the first order Fermi process of pitch angle scattering. We use a well established eigenfunction method to calculate the resulting spectra for infinitely thin shocks. Implications for GRBs and relativistic jets are discussed.
Cryogenics for Particle Accelerators and Detectors
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...
On Uncertainty Quantification in Particle Accelerators Modelling
Adelmann, Andreas
2015-01-01
Using a cyclotron based model problem, we demonstrate for the first time the applicability and usefulness of a uncertainty quantification (UQ) approach in order to construct surrogate models for quantities such as emittance, energy spread but also the halo parameter, and construct a global sensitivity analysis together with error propagation and $L_{2}$ error analysis. The model problem is selected in a way that it represents a template for general high intensity particle accelerator modelling tasks. The presented physics problem has to be seen as hypothetical, with the aim to demonstrate the usefulness and applicability of the presented UQ approach and not solving a particulate problem. The proposed UQ approach is based on sparse polynomial chaos expansions and relies on a small number of high fidelity particle accelerator simulations. Within this UQ framework, the identification of most important uncertainty sources is achieved by performing a global sensitivity analysis via computing the so-called Sobols' ...
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
Control microprocessor system for charge particle channeling
International Nuclear Information System (INIS)
Control microprocessor systems are widely applied not only in designing industrial robots but in providing functioning of different experimental plants. The experiment control system for charge particle channeling has been considered in the paper. Flexibility, relatively low cost and high reliability are advantages of these systems
Space charge in linear accelerators workshop. [Eighteen papers
Energy Technology Data Exchange (ETDEWEB)
Jameson, R.A. (ed.)
1978-05-01
Nineteen papers and three summary sessions (theoretical, simulation codes, and experimental approach) are presented on the effects of space charge in linear accelerators. A separate abstract was prepared for each paper for inclusion in Energy Research Abstracts (ERA). (PMA)
Charged Particles' Tunneling from Noncommutative Charged Black Hole
Mehdipour, S Hamid
2010-01-01
We apply the tunneling process of charged massive particles through the quantum horizon of a Reissner-Nordstr\\"om black hole in a new noncommutative gravity scenario. In this model, the tunneling amplitude on account of noncommutativity influences in the context of coordinate coherent states is modified. Our calculation points out that the emission rate satisfies the first law of black hole thermodynamics and is consistent with an underlying unitary theory.
Charged particles' tunneling from a noncommutative charged black hole
Mehdipour, S. Hamid
2010-01-01
We apply the tunneling process of charged massive particles through the quantum horizon of a Reissner-Nordstrom black hole in a new noncommutative gravity scenario. In this model, the tunneling amplitude on account of noncommutativity influences in the context of coordinate coherent states is modified. Our calculation points out that the emission rate satisfies the first law of black hole thermodynamics and is consistent with an underlying unitary theory.
AXEL–2014: Introduction to Particle Accelerators
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...
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
Argonne lectures on particles accelerator magnets
International Nuclear Information System (INIS)
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 Nb3Sn) and we explain in details the manufacturing of NbTi wires and cables (lecture 3). We also present the difficulties of processing and insulating Nb3Sn 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 cosθ and cos 2θ 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 requirements on the performance
CAS CERN Accelerator School: Superconductivity in particle accelerators. Proceedings
International Nuclear Information System (INIS)
These proceedings present the lectures given at the ninth specialized course organized by the CERN Accelerator School (CAS), the topic this time being ''Superconductivity in Particle Accelerators''. This course is basically a repeat of that given at the same location in 1988 whose proceedings were published as CERN 89-04. However, the opportunity was taken to improve the presentation of the various topics and to introduce the latest developments in this rapidly expanding field. First the basic theory of superconductivity is introduced. A review of the materials used for sc magnetics is followed by magnet design requirements, the influence of eddy and persistent currents, and the methods used to provide quench protection. Next follows the basic theory of sc cavities, their materials, high-gradient limitations, the problem of field emission and then their power couplers. After an introduction to cryogenics and cryoplants, the theory of superfluidity is presented followed by a review of the use of superfluid helium. Finally, two seminars detail the impact of superconductors in the design of the LHC and LEP2 accelerators. (orig.)
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.
International Nuclear Information System (INIS)
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.
Channeled particle acceleration by plasma waves in metals
International Nuclear Information System (INIS)
A solid state accelerator concept utilizing particle acceleration along crystal channels by longitudinal electron plasma waves in a metal is presented. Acceleration gradients of order 100 GV/cm are theoretically possible. Particle dechanneling due to electron multiple scattering can be eliminated with a sufficiently high acceleration gradient. Plasma wave dissipation and generation in metals are also discussed
Particle acceleration in the vacuum gaps in black hole magnetospheres
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...
Electro-Optical Detection of Charged Particle Beams
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.
Charge-State Distributions of Accelerated ^{48}Ca Ions
Skobelev, N K; Astabatyan, R A; Vincour, J; Kulko, A A; Lobastov, S P; Lukyanov, S M; Markaryan, E R; Maslov, V A; Penionzhkevich, Yu E; Sobolev, Yu G; Ugryumov, V Yu
2003-01-01
A stepped pole broad-range magnetic analyzer has been used to measure the charge-state distributions of accelerated ^{48}Ca ions at the two incident energies 242.8 and 264.5 MeV after passing through thin carbon or gold target foils. The measured charge-state distributions and the mean equilibrium charge of the ^{48}Ca ions are compared with various calculations. It has been shown that the calculations can be used only for evaluation purposes.
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.
Relativistic particle acceleration in developing Alfv\\'{e}n turbulence
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.
Born expansions for charged particle scattering
International Nuclear Information System (INIS)
High-order terms in Born expansions of scattering amplitudes in powers of charge are frequently divergent when long-range Coulomb interactions are present asymptotically. Expansions which are free from these logarithmic divergences have been constructed recently. This paper illustrates these expansions with the simplest example, namely the non-relativistic Rutherford scattering of two charged particles. This approach represents an adequate framework for the calculation of transition amplitudes and a comprehensive starting point for the development of consistent perturbation approximations in multi-channel descriptions of strongly interacting atomic systems
Properties of acceleration sites in active regions as derived from heavy ion charge states
Kartavykh, Y.; Dröge, W.; Klecker, B.; Möbius, E.; Popecki, M.; Mason, G.; Krucker, S.
Charge states of heavy ions in solar energetic particle SEP events are determined by both the plasma conditions in the acceleration region and propagation effects The steep increase of the ionic charge of heavy ions as observed in all 3He- and Fe-rich SEP events suggests that stripping in a dense environment in the low corona is important in all these events The observed charge states and energy spectra of iron ions are used to infer the plasma conditions in the acceleration region by modelling the observations with a combined acceleration and propagation model that includes charge stripping acceleration coulomb losses and recombination in the corona and interplanetary propagation The interplanetary propagation includes anisotropic pitch-angle scattering on magnetic irregularities as well as magnetic focusing convection and adiabatic deceleration in the expanding solar wind To accurately derive the value of the scattering mean free path of particles the intensity profiles and anisotropy data from ACE and Wind spacecraft were used The comparison of the deduced parameters of the acceleration region with coronal density profiles shows that the acceleration of these ions takes place in closed magnetic structures in the low corona
Space charge effects in proton linear accelerators
International Nuclear Information System (INIS)
Space charge difficulties are relatively well known because of the inconveniences they cause, but the physical mechanisms by which they operate are obscure; an attempt was made to explain some of these mechanisms. The method chosen involves a numerical simulation of the beam; computer programs describing beam dynamics with space charge are presented; they are used to check results obtained elsewhere. A series of experiments was performed demonstrating that coupling phenomena produce an equalization of r. m. s. velocities in the 3 directions; new quantity (sort of hyper-emittance) is introduced: its growth between the input and output of a given linac is proportional to the beam intensity. (author)
CAS CERN Accelerator School: Applied geodesy for particle accelerators
International Nuclear Information System (INIS)
This specialized course addresses the many topics involved in the application of geodesy to large particle accelerators, though many of the techniques described are equally applicable to large construction projects and surveillance systems where the highest possible surveying accuracies are required. The course reflects the considerable experience gained over many years, not only at CERN but in projects all over the world. The methods described range from the latest approach using satellites to recent developments in conventional techniques. They include the global positioning system (GPS), its development, deployment and precision, the use of the Terrameter and the combination or comparison of its results with those of the GPS, the automation of instruments, the management of measurements and data, and the highly evolved treatment of the observations. (orig.)
Heavy charged particle dosimetry, theory and application
International Nuclear Information System (INIS)
Experiments were made to verify the theory of the transport of heavy particles through a medium using L-α-alaline for the detection of radiation. The dose response of L-α-alaline was measured for X-ray radiation of an energy of 4 to 16 MeV, electron radiation of an energy of 6, 10 and 20 MeV, low-LET radiation, 16 MeV and 6 MeV protons, 20 MeV particles and other charged particles. Of the measured dose responses RE values were experimentally obtained and compared with calculated results. Free and very stable radicals were obtained by radiation. Fading of low-LET and high-LET radiation was determined as induced by the said radicals. Using ESR spectra it was found that diverse chemical reactions take place in the track of high-LET particles. However, chemical reactions in the track of a heavy charged particle will be the same if the medium is homogeneously irradiated with low-LET radiation. (E.S.). 7 figs., 1 tab., 11 refs
Particle acceleration in the M87 jet
Eilek, J A; Lobanov, A; Eilek, Jean; Hardee, Philip; Lobanov, Andrei
2003-01-01
The wealth of high quality data now available on the M87 jet inspired us to carry out a detailed analysis of the plasma physical conditions in the jet. In a companion paper (Lobanov, Hardee & Eilek, this proceedings) we identify a double-helix structure within the jet, and apply Kelvin-Helmholtz stability analysis to determine the physical state of the jet plasma. In this paper we treat the jet as a test case for in situ particle acceleration. We find that plasma turbulence is likely to exist at levels which can maintain the energy of electrons radiating in the radio to optical range, consistent with the broadband spectrum of the jet.
Controlling Charged Particles with Inhomogeneous Electrostatic Fields
Herrero, Federico A. (Inventor)
2016-01-01
An energy analyzer for a charged-particle spectrometer may include a top deflection plate and a bottom deflection plate. The top and bottom deflection plates may be non-symmetric and configured to generate an inhomogeneous electrostatic field when a voltage is applied to one of the top or bottom deflection plates. In some instances, the top and bottom deflection plates may be L-shaped deflection plates.
Vortical field amplification and particle acceleration at rippled shocks
Fraschetti, F
2013-01-01
Supernova Remnants (SNRs) shocks are believed to accelerate charged particles and to generate strong turbulence in the post-shock flow. From high-energy observations in the past decade, a magnetic field at SNR shocks largely exceeding the shock-compressed interstellar field has been inferred. We outline how such a field amplification results from a small-scale dynamo process downstream of the shock, providing an explicit expression for the turbulence back-reaction to the fluid whirling. The spatial scale of the $X-$ray rims and the short time-variability can be obtained by using reasonable parameters for the interstellar turbulence. We show that such a vortical field saturation is faster than the acceleration time of the synchrotron emitting energetic electrons.
Charged particle layers in the Debye limit
International Nuclear Information System (INIS)
We develop an equivalent of the Debye-Hueckel weakly coupled equilibrium theory for layered classical charged particle systems composed of one single charged species. We consider the two most important configurations, the charged particle bilayer and the infinite superlattice. The approach is based on the link provided by the classical fluctuation-dissipation theorem between the random-phase approximation response functions and the Debye equilibrium pair correlation function. Layer-layer pair correlation functions, screened and polarization potentials, static structure functions, and static response functions are calculated. The importance of the perfect screening and compressibility sum rules in determining the overall behavior of the system, especially in the r→∞ limit, is emphasized. The similarities and differences between the quasi-two-dimensional bilayer and the quasi-three-dimensional superlattice are highlighted. An unexpected behavior that emerges from the analysis is that the screened potential, the correlations, and the screening charges carried by the individual layers exhibit a marked nonmonotonic dependence on the layer separation
ULF Waves and Diffusive Radial Transport of Charged Particles
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
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.
Motion of charged particles in the magnetosphere
International Nuclear Information System (INIS)
The adiabatic motion of charged particles in the magnetosphere has been investigated using Mead-Fairfield magnetospheric field model (Mead and Fairfield, 1975). Since the motion of charged particles in a dipolar field geometry is well understood, we bring out in this paper some important features in characteristic motion due to non-dipolar distortions in the field geometry. We look at the tilt averaged picture of the field configuration and estimate theoretically the parameters like bounce period, longitudinal invariant and the bounce averaged drift velocities of the charged particle in the Mead-Fairfield field geometry. These parameters are evaluated as a function of pitch angle and azimuthal position in the region of ring current (5 to 7 Earth radii from the centre of the Earth) for four ranges of magnetic activity. At different longitudes the non-dipolar contribution as a percentage of dipole value in bounce period and longitudinal invariant shows maximum variation for particles close to 900 pitch angles. For any low pitch angle, these effects maximize at the midnight meridian. The radial component of the bounce averaged drift velocity is found to be greatest at the dawn-dusk meridians and the contribution vanishes at the day and midnight meridians for all pitch angles. In the absence of tilt-dependent terms in the model, the latitudinal component of the drift velocity vanishes. On the other hand, the relative non-dipolar contribution to bounce averaged azimuthal drift velocity is very high as compared to similar contribution in other characteristic parameters of particle motion. It is also shown that non-dipolar contribution in bounce period, longitudinal invariant and bounce averaged drift velocities increases in magnitude with increase in distance and magnetic activity. (orig.)
A Symplectic Multi-Particle Tracking Model for Self-Consistent Space-Charge Simulation
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.
Charged particle traps physics and techniques of charged particle field confinement
Major, Fouad G; Werth, Günther
2005-01-01
This book provides an introduction and guide to modern advances in charged particle (and antiparticle) confinement by electromagnetic fields. Confinement in different trap geometries, the influence of trap imperfections, classical and quantum mechanical description of the trapped particle motion, different methods of ion cooling to low temperatures, and non-neutral plasma properties (including Coulomb crystals) are the main subjects. They form the basis of such applications of charged particle traps as high-resolution optical and microwave spectroscopy, mass spectrometry, atomic clocks, and, potentially, quantum computing
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.
Anomalous transport and particle acceleration at shocks
Duffy, P; Gallant, Y A; Dendy, R O
1995-01-01
The theory of first order Fermi acceleration at shocks assumes that particles diffuse due to scattering off slow-moving magnetic irregularities. However, cosmic rays are closely tied to magnetic field lines, and the transport process, particularly across the direction of the field, is likely to be more complicated. To describe cross field transport we employ recent extensions of the Rechester-Rosenbluth theory in localised stochastic regions of magnetic field. During acceleration at a shock and when the motion along the field is diffusive, there is a transition at a critical energy from \\lq\\lq sub-diffusive\\rq\\rq\\ motion, where the mean square displacement of a particle increases with time as t^{1/2}, to compound diffusion, a combined process involving diffusion along a magnetic field which is itself wandering. Requiring this critical energy to be less than the system cut-off in a SNR of radius R places an upper limit on the coherence length, \\lambda, of the magnetic field for which diffusive shock accelerati...
GPU accelerated particle visualization with Splotch
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.
Space Experiments with Particle Accelerators (SEPAC)
Taylor, William W. L.
1994-01-01
The scientific emphasis of this contract has been on the physics of beam ionosphere interactions, in particular, what are the plasma wave levels stimulated by the Space Experiments with Particle Accelerators (SEPAC) electron beam as it is ejected from the Electron Beam Accelerator (EBA) and passes into and through the ionosphere. There were two different phenomena expected. The first was generation of plasma waves by the interaction of the DC component of the beam with the plasma of the ionosphere, by wave particle interactions. The second was the generation of waves at the pulsing frequency of the beam (AC component). This is referred to as using the beam as a virtual antenna, because the beam of electrons is a coherent electrical current confined to move along the earth's magnetic field. As in a physical antenna, a conductor at a radio or TV station, the beam virtual antenna radiates electromagnetic waves at the frequency of the current variations. These two phenomena were investigated during the period of this contract.
Relevance of plasma science to particle accelerators
International Nuclear Information System (INIS)
In following the theme of this Symposium, ''Plasma Science and Its Applications,'' the authors may be suggesting to some readers that the other applications of Plasma Science somehow justify the existence of a field traditionally devoted to fusion energy. In fact, they do not believe that plasma science can or should be justified for its spin-off contributions. Nevertheless, the unity of science would be seriously threatened by a precipitous decline in the support for plasma science. It is that unity which repeatedly has been verified as one looks for how advances in one field are crucial to several other seemingly fundamentally different fields. Thus it is in this case, as a representative of the community of Particle Accelerator Scientists, that they show four significant areas in which the methods and the results of plasma science have been applied to Accelerator Science. They have deliberately skipped plasma ion sources which are perhaps the most obvious application of plasmas to accelerators. Two of their four examples are cases in which the computational methods of plasma science have been adopted, and two are examples in which the plasmas themselves are employed. One of each category are now actively in use and the other one in each category is being used to develop or design new devices
Investigation of charge balance in ion accelerator TEMP-4M
Khailov, I. P.; Pak, V. G.
2014-10-01
The paper presents the results of a study on the balance of charge in accelerator TEMP-4M operating in double-pulse mode with resistance load and ion diode. Crucially, it was found, that during the switching there is no losses of accumulated charge. It means, that all accumulated charge transferred to the load. However when the charge is transferred from the Marx generator to Blumlein line the half of accumulated charge is lost. Calibration of diagnostic equipment showed a good agreement between the calculated and experimental values of voltage and current. It means, that our diagnostic system is correct for registration parameters of the ion accelerator. A distinctive feature of the ion accelerators with self-magnetically insulated diode is that there is no need to use additional energy source for the creation of an external magnetic field. That's why the efficiency of ion diodes with an external magnetic field is not more than 10-15%. The efficiency of energy conversion in self-magnetically insulated diodes will be determined by not only the efficiency of the diode, but the energy losses in the units of the accelerator. The aim of the researches is the analysis of the balance of charge in units of the ion beams pulsed generator and definition of the most significant channels of energy loss.
Linear induction accelerator for charge-neutralized ion beams in inertial confinement fusion
Energy Technology Data Exchange (ETDEWEB)
Batishchev, O.V.; Golota, V.I.; Karas, V.I.; Kiyashko, V.A.; Kornilov, E.A.; Sigov, Yu.S.; Silaev, I.I.; Fainberg, Ya.B. [Khar`kov Physico-Technical Institute (Russian Federation)
1993-05-01
Results are presented from experimental, analytical, and numerical studies of the physical processes that occur in a high-current ion induction accelerator (the ion linac IINDUS). The experiments were performed in a module of the IINDUS accelerator consisting of an injector of gaseous or metallic ions and two induction sections with magnetically insulated cusps in the accelerator gaps filled with plasma. The following ion beam parameters were found: 2-3 kA, 0.5 MeV, 0.5 {mu}s. The two most dangerous instabilities effecting beam quality were studied. These are the high-frequency beam-plasma instability and the filamentation instability. A nonlinear analytical theory of charge neutralization of a high-current ion beam in magnetically insulated accelerating gaps is presented. In order to develop diagnostics for high-current beams of accelerated particles the amplitude and shape of the acoustic pulse excited in a metal target by the particles have been studied theoretically and experimentally as functions of the beam parameters. The possibility of practical application of this acceleration in ICF has been studied using a 2.5-dimensional relativistic electromagnetic code to simulate the processes of acceleration, charge neutralization, and stability of the ion beam in the accelerating channel. The results provide evidence in favor of the prospects for this direction of research. 70 refs., 13 figs.
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.
Metastable states of plasma particles close to a charged surface
International Nuclear Information System (INIS)
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
Radiation reaction for a massless charged particle
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.
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.
Radiation reaction for a massless charged particle
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.
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.
Regulating The Performance Parameters Of Accelerated Particles
International Nuclear Information System (INIS)
Design, fabrication and utilization of electron sources have gained unique importance in fundamental research and industrial applications. In any electron gun the geometry of the electrodes decides the main beam optics comprising of uniform flow of electrons and beam waist. So that, in the present work, A Pierce-type electron gun with spherical anode has been numerically analyzed and validated experimentally. The regulated output beam is applied to poly (ethylene terephthalate) PET membrane to improve its surface wettability. In the simulation study of the electron gun, it has been proven that, around a certain value of the aspect ratio, the resultant beam geometry could be suitably controlled. The minimum electric field required to prevent beam expansion due to space charge effect has been estimated and it is found to be proportional to the cubic root of the distance from the anode to the target. Also, it is proved that the minimum beam radius is realized at the minimum beam perveance and the maximum beam convergence angle. As a result, this reveals that, the gun geometry controls the beam emittance. The gun design analysis proposed here helps to choose the better operating conditions suitable for low energy electron beam bombardment and/or injection applications into plasma medium for plasma acceleration.Experimentally, an investigation has been made for the extraction characteristics and beam diagnosis for the electron gun. The accelerating voltage increases the electron beam currents up to 250 mA at accelerating voltage 75 kV and decreases the beam perveance, beam waist and beam emittance. The minimum beam radius could be found at the minimum beam perveance and maximum convergence angle. Also the increase of the accelerating voltage increases the beam fluence rate up to 1.3 x 1019 e/min.cm2 due to the increase of the extracted current. Tracing the electron beam profile by X-Y probe scanner along the beam line at two different places reveals that the spherical
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.
Geometric Product Formula for Charged Accelerating Black Hole
Pradhan, Parthapratim
2016-01-01
We evaluate the geometric product formula i.e. area (or entropy) product formula of outer horizon (${\\cal H}^{+}$) and inner horizon (${\\cal H}^{-}$) for charged accelerating black hole. We find that mass-independent area functional relation of ${\\cal H}^{\\pm}$ for this black hole in terms of black hole charge, acceleration, cosmological constant and \\emph{cosmic string tension} respectively. We also compute the \\emph{Penrose inequality} for this black hole. Finally we compute the specific heat for this BH to determine the local thermodynamic stability of this black hole. Under certain criterion the black hole displayed second order phase transition.
Sound from charged particles in liquids
International Nuclear Information System (INIS)
Two directions of sound application appearing during the charged particles passing through liquid - in biology and for charged particles registration are considered. Application of this sound in radiology is determined by a contribution of its hypersound component (approximately 109 Hz) to radiology effect of ionizing radiation on micro-organisms and cells. Large amplitudes and pressure gradients in a hypersound wave have a pronounced destructive breaking effect on various microobjects (cells, bacteria, viruses). An essential peculiarity of these processes is the possibility of control by choosing conditions changing hypersound generation, propagation and effect. This fact may lead not only to the control by radiaiton effects but also may explain and complete the analogy of ionizing radiation and ultrasound effect on bioobjects. The second direction is acoustic registration of passing ionizing particles. It is based on the possibility of guaranteed signal reception from a shower with 1015-1016 eV energy in water at distances of hundreds of meters. Usage of acoustic technique for neutrino registration in the DUMAND project permits to use a detecting volume of water with a mass of 109 t and higher
Alpha particles diffusion due to charge changes
Clauser, C. F.; Farengo, R.
2015-12-01
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.
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.
New frontier of laser particle acceleration: driving protons to 80 MeV by radiation pressure
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...
The dynamics of charged particles in turbulent astrophysical plasmas
Dung, Rudiger; Petrosian, Vahe
1994-01-01
We consider the resonant interaction of energetic charged particles and transverse plasma wave propagating parallel and/or antiparallel to the uniform magnetic field B(sub 0) in an underlying background plasma of density n. The coupling of the plasma waves and the energetic particles will be controlled by the ratio n/(the absolute value of B(sub 0)(exp 2). A variation of this ratio leads to a strong variation of the dynamics of the energetic particles. By taking into account the whole transverse plasma branch for the resonant interaction we discuss the influence of the background plasma density, the background magnetic field, the cross helicity, and the magnetic helicities on the dynamics of charged particles in astrophysical plasmas. It is shown that low-energy electrons can be accelerated efficiently by the higher electromagnetic waves and short-wavelength whistlers for low values of the ratio n/(the absolute value of B(sub 0)(exp 2), which means for low values of the ratio of plasma frequency to gyrofrequency.
A stochastic-hydrodynamic model of halo formation in charged particle beams
Petroni, Nicola Cufaro; De Martino, Salvatore; De Siena, Silvio; Illuminati, Fabrizio
2003-01-01
The formation of the beam halo in charged particle accelerators is studied in the framework of a stochastic-hydrodynamic model for the collective motion of the particle beam. In such a stochastic-hydrodynamic theory the density and the phase of the charged beam obey a set of coupled nonlinear hydrodynamic equations with explicit time-reversal invariance. This leads to a linearized theory that describes the collective dynamics of the beam in terms of a classical Schr\\"odinger equation. Taking ...
Charged particle beam current monitoring tutorial
International Nuclear Information System (INIS)
A tutorial presentation is made on topics related to the measurement of charged particle beam currents. The fundamental physics of electricity and magnetism pertinent to the problem is reviewed. The physics is presented with a stress on its interpretation from an electrical circuit theory point of view. The operation of devices including video pulse current transformers, direct current transformers, and gigahertz bandwidth wall current style transformers is described. Design examples are given for each of these types of devices. Sensitivity, frequency response, and physical environment are typical parameters which influence the design of these instruments in any particular application. Practical engineering considerations, potential pitfalls, and performance limitations are discussed
CVD diamond sensors for charged particle detection
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).
Device for measuring charge density distribution in charged particle beams
International Nuclear Information System (INIS)
A device to measure charge density distribution in charged particle beams has been described. The device contains a set of hollow interinsulated current-receiving electrodes, recording system, and cooling system. The invention is aimed at the increase of admissible capacity of the beams measured at the expense of cooling efficiency increase. The aim is achieved by the fact, that in the device a dynamic evaporating-condensational cooling of electrodes is realized by means of cooling agent supply in perpendicular to their planes through the tubes introduced inside special cups. Spreading in radial direction over electrode surface the cooling agent gradually and intensively washes the side surface of the cup, after that, it enters the cooling cavity in the form of vapour-liquid mixture. In the cavity the cooling agent, supplied using dispensina and receiving collectors in which vapoUr is condensed, circulates. In the device suggested the surface of electrode cooling is decreased significantly at the expense of side surface of the cups which receives the electrode heat
Solar flare particle acceleration in collapsing magnetic traps
Grady, Keith J.
2012-01-01
The topic of this thesis is a detailed investigation of different aspects of the particle acceleration mechanisms operating in Collapsing Magnetic Traps (CMTs), which have been suggested as one possible mechanism for particle acceleration during solar flares. The acceleration processes in CMTs are investigated using guiding centre test particle calculations. Results including terms of different orders in the guiding centre approximation are compared to help identify which of the terms a...
A Threshold for Laser-Driven Linear Particle Acceleration in Unbounded Vacuum
Wong, Liang Jie
2013-01-01
We hypothesize that a charged particle in unbounded vacuum can be substantially accelerated by a force linear in the electric field of a propagating electromagnetic wave only if the accelerating field is capable of bringing the particle to a relativistic energy in its initial rest frame during the interaction. We consequently derive a general formula for the acceleration threshold of such schemes and support our conclusion with the results of numerical simulations over a broad range of parameters for different kinds of pulsed laser beams.
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.
Multiparametric ionization probes for monitoring accelerated particle beams
International Nuclear Information System (INIS)
Paper describes high-sensitive ionization probes of transverse cross section of accelerated particle beam. Image of beam real cross section is formed at the display of electron-optical converter on the basis of multichannel plates, is recorded by TV camera and is processes and presented by means of computer. Probe structures for 1-100 MeV energy round and strip beams are developed and tested. Distortions of beam cross section image under the effect of the external magnetic field and of space charge field are estimated. The results of the first investigations into prototype ionization probes to control form, duration, phase of cyclotron beam microclusters are presented. 13 refs.; 9 figs
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.
Charge states of Mg and Si from stochastic acceleration in impulsive solar flares
Kartavykh, Yu. Yu.; Wannawichian, S.; Ruffolo, D.; Ostryakov, V. M.
2002-07-01
We consider the acceleration of heavy ions in impulsive solar flares. In particular, we have performed Monte Carlo simulations of stochastic acceleration by Alfvén wave turbulence, and compare new results for magnesium and silicon ions with previous results for iron. The model takes into account stripping due to collisions with ambient electrons and heavy particles (protons and He +2) which becomes increasingly important for more energetic ions, as well as radiative and dielectronic recombination due to collisions with electrons. Spatial diffusion and Coulomb losses are also taken into account. For comparison, we also calculate equilibrium mean charges. We examine the effects of plasma parameters on the calculated energy-dependent charge state distributions of these elements, which can be compared with results from space-borne instruments in order to put constraints on the physical environment of the acceleration region.
Aberration compensation in charged particle projection lithography
International Nuclear Information System (INIS)
Projection systems offer the opportunity to increase the throughput for charged particle lithography, because such systems image a large area of a mask directly on to a wafer as a single shot. Shots have to be imaged over a certain range of off-axis distances at the wafer to increase the writing speed, because shot sizes are limited to about 0.25x0.25 mm2 due to aberrations. In a projection system with only lenses, however, the aberrations for off-axis shots are still very large, and some aberration compensation elements need to be introduced. In this paper, three aberration compensation elements (deflectors, stigmators and dynamic focus lenses) are first discussed, a suite of newly developed software, called PROJECTION, based on this principle and our unified aberration theory is then described, and an illustrative example computed with the software is finally given
Beam-driven, Plasma-based Particle Accelerators
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.
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.
Theoretical and experimental studies of a plasma- and particle accelerator
International Nuclear Information System (INIS)
Using the combination of a coaxial plasma accelerator with a compression coil a dense and fast plasma flow can be produced and applied for gas-dynamical acceleration of particles. The theoretical and experimental studies presented here contribute to a better understanding of the acceleration process and to the operational application of the system as a micrometeor simulator. (orig.)
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.
Charge and Current Compensation of Intense Charged Beams in Future Accelerators
Riege, H
1998-01-01
Proposals for future high-energy accelerators are characterized by demands for increasingly intense and energetic beams. The classical operation of high-current accelerators is severely constrained by collective electrodynamic phenomena, such as problems related to space-charge, to high-current flow, to beamstrahlung and pair production. These detrimental electrodynamic effects dominate the dynamic s and the collision interactions of high-intensity beams. With the introduction of soft space-charge and current compensation techniques utilizing low- to medium-energy lepton beams with charge polari ty opposite to that of the beams to be neutralized, all electromagnetic high-intensity limitations may be removed. The application of beam compensation is proposed for various sections of different ty pes of classical accelerator systems, such as for ion sources and the low-energy beam transport sections of ion linacs, for the crossing points of circular and linear colliders and for the final focii of ion beam fusion ...
MODELING CHARGE RELAXATION ON SURFACES OF PARTICLES SUSPENDED IN LIQUID
Institute of Scientific and Technical Information of China (English)
Guoqing Gu; Kin Wah Yu
2005-01-01
A general theory on charges relaxation process in particle-fluid systems is introduced in this article. The method to derive analytical solutions for the charge relaxation equation is illustrated, and some respects for this theory are discussed in detail.
Neural Networks for Modeling and Control of Particle Accelerators
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.
Horizon structure of rotating Bardeen black hole and particle acceleration
International Nuclear Information System (INIS)
We investigate the horizon structure and ergosphere in a rotating Bardeen regular black hole, which has an additional parameter (g) due to the magnetic charge, apart from the mass (M) and the rotation parameter (a). Interestingly, for each value of the parameter g, there exists a critical rotation parameter (a = aE), which corresponds to an extremal black hole with degenerate horizons, while for a < aE it describes a non-extremal black hole with two horizons, and no black hole for a > aE. We find that the extremal value aE is also influenced by the parameter g, and so is the ergosphere. While the value of aE remarkably decreases when compared with the Kerr black hole, the ergosphere becomes thicker with the increase in g.We also study the collision of two equal mass particles near the horizon of this black hole, and explicitly show the effect of the parameter g. The center-of-mass energy (ECM) not only depend on the rotation parameter a, but also on the parameter g. It is demonstrated that the ECM could be arbitrarily high in the extremal cases when one of the colliding particles has a critical angular momentum, thereby suggesting that the rotating Bardeen regular black hole can act as a particle accelerator. (orig.)
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?
EXITATION OF ELECTROMAGNETIC RADIATION, NUCLEAR REACTION AND PARTICLES DECAY BY THE ACCELERATION
Directory of Open Access Journals (Sweden)
Trunev A. P.
2015-05-01
Full Text Available The article discusses the excitation of electromagnetic radiation, nuclear reactions and decays of particles by the acceleration of charges, atomic nuclei and the macroscopic volumes of matter. The motion of charged particles in a magnetic trap used for plasma confinement was computed. We propose a model of the electromagnetic radiation of a charge moving in a non-inertial reference frame in general relativity. We have also constructed a theory of perturbation with using a wave equation with small parameters, taking into account a characteristic radius of the trajectory of the electrons as they move in a magnetic field. It was found that in the first approximation, the radiation back-reaction force depends on the acceleration of the charge. For the simulating of processes in hadrons and nuclei we used Yang-Mills theory and the metric, describes the acceleration and rotating reference frame in general relativity. We consider the scalar glueball model for an arbitrary dependence of acceleration and angular velocity of the system on time. The numerical model of wave propagation in non-inertial reference frame for the geometry of system of one, two or three spatial dimensions was tested. In the numerical experiments shown that the acceleration of the system leads to instability, leading to an unlimited increase in the amplitude of waves, which is interpreted as a decay of system. It was found that there are critical values of acceleration above which the instability develops
Recent Results in Charged-Composite Particle Scattering
Alt, Erwin O.
1997-01-01
A brief overview is given of some recent advances in charged-composite particle scattering. On the theoretical side, I address the three-charged particle wave function asymptotics, the nonperturbative investigation of the long-range behaviour of the optical potential, and the question of the compactness of the kernels of the momentum space integral equations for three charged particles. Among the more practical developments, I report on results of numerical calculations of so-called "triangle...
Inertial-particle accelerations in turbulence: a Lagrangian closure
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 ...
Charged and Neutral Particles Channeling Phenomena Channeling 2008
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
Use of CMOS imagers to measure high fluxes of charged particles
Servoli, L.; Tucceri, P.
2016-03-01
The measurement of high flux charged particle beams, specifically at medical accelerators and with small fields, poses several challenges. In this work we propose a single particle counting method based on CMOS imagers optimized for visible light collection, exploiting their very high spatial segmentation (> 3 106 pixels/cm2) and almost full efficiency detection capability. An algorithm to measure the charged particle flux with a precision of ~ 1% for fluxes up to 40 MHz/cm2 has been developed, using a non-linear calibration algorithm, and several CMOS imagers with different characteristics have been compared to find their limits on flux measurement.
Particle Acceleration in an Evolving Network of Unstable Current Sheets
Vlahos, L; Lepreti, F
2004-01-01
We study the acceleration of electrons and protons interacting with localized, multiple, small-scale dissipation regions inside an evolving, turbulent active region. The dissipation regions are Unstable Current Sheets (UCS), and in their ensemble they form a complex, fractal, evolving network of acceleration centers. Acceleration and energy dissipation are thus assumed to be fragmented. A large-scale magnetic topology provides the connectivity between the UCS and determines in this way the degree of possible multiple acceleration. The particles travel along the magnetic field freely without loosing or gaining energy, till they reach a UCS. In a UCS, a variety of acceleration mechanisms are active, with the end-result that the particles depart with a new momentum. The stochastic acceleration process is represented in the form of Continuous Time Random Walk (CTRW), which allows to estimate the evolution of the energy distribution of the particles. It is found that under certain conditions electrons are heated a...
Acceleration and Particle Field Interactions of Cosmic Rays II: Calculations
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...
Interaction of free charged particles with a chirped electromagnetic pulse
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
Particle-acceleration timescales in TeV blazar flares
Tammi, Joni
2008-01-01
Observations of minute-scale flares in TeV Blazars place constraints on particle acceleration mechanisms in those objects. The implications for a variety of radiation mechanisms have been addressed in the literature; in this paper we compare four different acceleration mechanisms: diffusive shock acceleration, second-order Fermi, shear acceleration and the converter mechanism. When the acceleration timescales and radiative losses are taken into account, we can exclude shear acceleration and the neutron-based converted mechanism as possible acceleration processes in these systems. The first-order Fermi process and the converter mechanism working via SSC photons are still practically instantaneous, however, provided sufficient turbulence is generated on the timescale of seconds. We propose stochastic acceleration as a promising candidate for the energy-dependent time delays in recent gamma-ray flares of Markarian 501.
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.
Fractional dynamics of charged particles in magnetic fields
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.
Dynamics of fast charged particle beam rotation in bended crystals
International Nuclear Information System (INIS)
Dynamics of fast charged particle beam rotation in a bended monocrystal is considered. Face and volume mechanisms of capture in channels are taken into account simultaneously in the model presented. Functions of distribution in transverse energies (φ) of channeled and dechanneled particles are obtained. Charge-energy ''scale invariance'' in ion channeling with charge Z in a bended crystal determined by scale parameter W=pv/Z (p and v are pulse and velocity local to transverse planes) follows from the model presented
Particles and scalar waves in noncommutative charged black hole spacetime
Bhar, Piyali; Rahaman, Farook; Biswas, Ritabrata(Indian Institute of Engineering Sceince and Technology Shibpur (Formerly, Bengal Engineering and Science University Shibpur), 711 013, Howrah, West Bengal, India); Mondal, U. F.
2015-01-01
In this paper we have discussed geodesics and the motion of test particle in the gravitational field of noncommutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately. A comparative study of noncommutative charged black hole and usual Reissner-Nordstrom black hole has been done. The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.
Particles and Scalar Waves in Noncommutative Charged Black Hole Spacetime
Piyali, Bhar; Farook, Rahaman; Ritabrata, Biswas; U. F., Mondal
2015-07-01
In this paper we have discussed geodesics and the motion of test particle in the gravitational field of non-commutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately. A comparative study of noncommutative charged black hole and usual Reissner-Nordström black hole has been done. The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.
Energy-Dependent Ionization States of Shock-Accelerated Particles in the Solar Corona
Reames, Donald V.; Ng, C. K.; Tylka, A. J.
2000-01-01
We examine the range of possible energy dependence of the ionization states of ions that are shock-accelerated from the ambient plasma of the solar corona. If acceleration begins in a region of moderate density, sufficiently low in the corona, ions above about 0.1 MeV/amu approach an equilibrium charge state that depends primarily upon their speed and only weakly on the plasma temperature. We suggest that the large variations of the charge states with energy for ions such as Si and Fe observed in the 1997 November 6 event are consistent with stripping in moderately dense coronal. plasma during shock acceleration. In the large solar-particle events studied previously, acceleration occurs sufficiently high in the corona that even Fe ions up to 600 MeV/amu are not stripped of electrons.
Particle Accelerators and Detectors for medical Diagnostics and Therapy
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 ...
Seventy Five Years of Particle Accelerators (LBNL Summer Lecture Series)
International Nuclear Information System (INIS)
Summer Lecture Series 2006: Andy Sessler, Berkeley Lab director from 1973 to 1980, sheds light on the Lab's nearly eight-decade history of inventing and refining particle accelerators, which continue to illuminate the nature of the universe.
Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
Zharkova, V. V.; Arzner, K.; Benz, A. O.; Browning, P.; Dauphin, C.; Emslie, A. G.; Fletcher, L.; Kontar, E. P.; Mann, G.; Onofri, M.; Petrosian, V.; Turkmani, R.; Vilmer, N.; Vlahos, L.
2011-09-01
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.
Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
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.
Exploring Particle Acceleration in Gamma-Ray Binaries
Bosch-Ramon, V
2011-01-01
Binary systems can be powerful sources of non-thermal emission from radio to gamma rays. When the latter are detected, then these objects are known as gamma-ray binaries. In this work, we explore, in the context of gamma-ray binaries, different acceleration processes to estimate their efficiency: Fermi I, Fermi II, shear acceleration, the converter mechanism, and magnetic reconnection. We find that Fermi I acceleration in a mildly relativistic shock can provide, although marginally, the multi-10 TeV particles required to explain observations. Shear acceleration may be a complementary mechanism, giving particles the final boost to reach such a high energies. Fermi II acceleration may be too slow to account for the observed very high energy photons, but may be suitable to explain extended low-energy emission. The converter mechanism seems to require rather high Lorentz factors but cannot be discarded a priori. Standard relativistic shock acceleration requires a highly turbulent, weakly magnetized downstream med...
Controlled Electron Injection into Plasma Accelerators and Space Charge Estimates
International Nuclear Information System (INIS)
Plasma based accelerators are capable of producing electron sources which are ultra-compact (a few microns) and high energies (up to hundreds of MeVs) in much shorter distances than conventional accelerators. This is due to the large longitudinal electric field that can be excited without the limitation of breakdown as in RF structures.The characteristic scale length of the accelerating field is the plasma wavelength and for typical densities ranging from 1018 - 1019 cm-3, the accelerating fields and scale length can hence be on the order of 10-100GV/m and 10-40 mu m, respectively. The production of quasimonoenergetic beams was recently obtained in a regime relying on self-trapping of background plasma electrons, using a single laser pulse for wakefield generation. In this dissertation, we study the controlled injection via the beating of two lasers (the pump laser pulse creating the plasma wave and a second beam being propagated in opposite direction) which induce a localized injection of background plasma electrons. The aim of this dissertation is to describe in detail the physics of optical injection using two lasers, the characteristics of the electron beams produced (the micrometer scale plasma wavelength can result in femtosecond and even attosecond bunches) as well as a concise estimate of the effects of space charge on the dynamics of an ultra-dense electron bunch with a large energy spread
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.
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.
Nonlinear theory of diffusive acceleration of particles by shock waves
International Nuclear Information System (INIS)
Among the various acceleration mechanisms which have been suggested as responsible for the nonthermal particle spectra and associated radiation observed in many astrophysical and space physics environments, diffusive shock acceleration appears to be the most successful. We review the current theoretical understanding of this process, from the basic ideas of how a shock energizes a few reactionless particles to the advanced nonlinear approaches treating the shock and accelerated particles as a symbiotic self-organizing system. By means of direct solution of the nonlinear problem we set the limit to the test-particle approximation and demonstrate the fundamental role of nonlinearity in shocks of astrophysical size and lifetime. We study the bifurcation of this system, proceeding from the hydrodynamic to kinetic description under a realistic condition of Bohm diffusivity. We emphasize the importance of collective plasma phenomena for the global flow structure and acceleration efficiency by considering the injection process, an initial stage of acceleration and, the related aspects of the physics of collisionless shocks. We calculate the injection rate for different shock parameters and different species. This, together with differential acceleration resulting from nonlinear large-scale modification, determines the chemical composition of accelerated particles. The review concentrates on theoretical and analytical aspects but our strategic goal is to link the fundamental theoretical ideas with the rapidly growing wealth of observational data. (author)
Accelerating research into the Higgs boson particle
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)
Photon production by charged particles in narrow optical fibers
Artru, X.; Ray, C.
2006-01-01
Presented at International Conference on Charged and Neutral Particles Channeling Phenomena, Frascati, Italy, July 3-7, 2006. - Theorie, CAS A charged particle passing through or by an optical fiber induces emission of light guided by the fiber. The formula giving the spontaneous emission amplitude are given in the general case when the particle trajectory is not parallel to the fiber axis. At small angle, the photon yield grows like the inverse power of the angle and in the parallel limit...
Massive Vector Particles Tunneling From Noncommutative Charged Black Holes
Övgün, Ali
2015-01-01
In this paper, we investigate the tunneling process of charged massive bosons $W^{\\pm}$ (spin-1 particles) from noncommutative charged black holes such as charged RN black holes and charged BTZ black holes. By applying the WKB approximation and by using the Hamilton-Jacobi equation we derive the tunneling rate and the corresponding Hawking temperature for those black holes configuration. The tunneling rate shows that the radiation deviates from pure thermality and is consistent with an underlying unitary theory.
Vacuum improvements for ultra high charge state ion acceleration
International Nuclear Information System (INIS)
The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10-6 down to about 7 x 10-7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe27+ at 603 MeV, more than doubled for a Bi41+ beam (from 1.9% to 4.6%) at 904 MeV and tripled for a U47+ beam (from 1.2% to 3.6%) at 1,115 MeV. At about 5 NeV/nucleon 92 enA (2.2 pnA) for Bi41+ and 14 enA (0.3 pnA) for U47+ were extracted ut of the 88-Inch Cyclotron Ion beams with charge states as high as U64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models
An improved limit on the charge of antihydrogen from stochastic acceleration
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.
Non-linear Particle Acceleration in Oblique Shocks
Ellison, D C; Jones, F C; Ellison, Donald C.; Baring, Matthew G.; Jones, Frank C.
1996-01-01
We have developed a Monte Carlo technique for self-consistently calculating the hydrodynamic structure of oblique, steady-state shocks, together with the first-order Fermi acceleration process and associated non-thermal particle distributions. This is the first internally consistent treatment of modified shocks that includes cross-field diffusion of particles. Our method overcomes the injection problem faced by analytic descriptions of shock acceleration, and the lack of adequate dynamic range and artificial suppression of cross-field diffusion faced by plasma simulations; it currently provides the most broad and versatile description of collisionless shocks undergoing efficient particle acceleration. We present solutions for plasma quantities and particle distributions upstream and downstream of shocks, illustrating the strong differences observed between non-linear and test-particle cases. It is found that there are only marginal differences in the injection efficiency and resultant spectra for two extreme ...
Hovestadt, D.; Klecker, B.; Hoefner, H.; Scholer, M.; Gloeckler, G.; Ipavich, F. M.
1982-01-01
An analysis is presented of the ionic charge state distribution of He, C, O and Fe in the energetic storm particle event of September 28-29, 1978. Data were obtained with the ULEZEQ electrostatic analyzer-proportional counter on board the ISEE 3 spacecraft. The He(+)/He(++) ratio between 0.4 and 1 MeV/n is shown to be significantly lower during the energetic storm particle event than during the preceding period of solar flare particle enhancement, with a temporal evolution similar to that of the Fe/He ratio as reported by Klecker et al. (1981). Increases in the mean charge state for oxygen by about 3% and for iron by about 16% are also noted. The temporal variations in charge states are accounted for in terms of first-order Fermi acceleration of the pre-existing solar flare particles by a propagating interplanetary shock wave.
An improved limit on the charge of antihydrogen from stochastic acceleration.
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
2016-01-21
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| 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. PMID:26791725
Particle acceleration by collisionless shocks containing large-scale magnetic-field variations
Guo, F; Kota, J
2010-01-01
Diffusive shock acceleration at collisionless shocks is thought to be the source of many of the energetic particles observed in space. Large-scale spatial variations of the magnetic field has been shown to be important in understanding observations. The effects are complex, so here we consider a simple, illustrative model. Here, we solve numerically the Parker transport equation for a shock in the presence of large-scale sinusoidal magnetic-field variations. We demonstrate that the familiar planar-shock results can be significantly altered as a consequence of large-scale, meandering magnetic lines of force. Because perpendicular diffusion coefficient $\\kappa_\\perp$ is generally much smaller than parallel diffusion coefficient $\\kappa_\\parallel$, the energetic charged particles are trapped and preferentially accelerated along the shock front in the regions where the connection points of magnetic field lines intersecting the shock surface converge, and thus create the "hot spots" of the accelerated particles. F...
Influence of Sedimentation on Crystallization of Charged Colloidal Particles
Institute of Scientific and Technical Information of China (English)
Xuan Du; Sheng-hua Xu; Zhi-wei Sun; Lei Liu
2012-01-01
The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions on dynamic belavior of a colloidal system.Experiments on crystallization of charged colloidal microspheres with diameter of 98 nm dispersed in density-matched and -unmatched media (mixtures of H2Oand D2O in proper proportion) are compared to examine the influence of sedimentation.Reflection spectra of colloidal suspensions were used to monitor the crystallization process.Results showed that the crystal size of the density-unmatched (namely,in the presence of sedimentation) sample grew faster than that of the density-matched (in the absence of sedimentation) case at the initial stage of the crystallization,and then the latter overtook and outstripped the former.To explain these observations,we assume that in the settling of crystals sedimentation facilitates result in more particles getting into the crystal structures.However,as the crystals increase to varying sizes,the settling velocities become large and hydrodynamic friction strips off some particles from the delicate crystal structures.Overall,the sedimentation appears to accelerate the crystal size growth initially and then retard the growth.In addition,the crystal structures formed under microgravity were more closely packed than that in normal gravity.
Particle Acceleration and Heating by Turbulent Reconnection
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.
Erokhin, Nikolay; Loznikov, Vladimir; Shkevov, Rumen; Zolnikova, Nadezhda; Mikhailovskaya, Ludmila
2016-07-01
The analysis of experimental data on the spectra of cosmic rays (CR) has shown their variability on time scales of a few years, in particular, CR variations observed in E / Z range from TeV to 10000 TeV, where E is the energy of the particle, Z is its charge number. Consequently, the source of these variations must be located at a distance of no more than 1 parsec from the sun in the closest local interstellar clouds. As a mechanism of such variations appearance it is considered the surfatron acceleration of CR particles by electromagnetic wave in a relatively quiet space plasma. On the basis of developed model the numerical calculations were performed for particle capture dynamics (electrons, protons, helium and iron nuclei) in the wave effective potential well with a following growth their energy by 3-6 orders of magnitude. Optimal conditions for the implementation of charged particles surfatron acceleration in space plasma, the rate of trapped particles energy growth, the dynamics of wave phase on the captured particle trajectory, a temporal dynamics of components for charge impulse momentum and speed were studied. It is indicated that the capture of a small fraction of particles by wave for energies about TeV and less followed by their surfatron acceleration to an energy of about 10000 TeV will lead to a significant increase in the CR flux at such high energies. Thus CL flow variations are conditioned by changes in the space weather parameters
Classical electrodynamics of a particle with maximal acceleration corrections
Energy Technology Data Exchange (ETDEWEB)
Feoli, A.; Lambiase, G. [Baronissi, Univ. (Italy). Dipt. di Scienze Fisiche ``E. R. Caianiello``]|[INFN, Naples (Italy); Papini, G. [Regina, Univ. (Canada). Dept. of Physics; Scarpetta, G. [Baronissi, Univ. (Italy). Dipt. di Scienze Fisiche ``E. R. Caianiello``]|[INFN, Naples (Italy)]|[International Institute for Advanced Scientific Studies, Vietri sul Mare (Italy)
1997-06-01
They calculate the first-order maximal acceleration corrections to the classical electrodynamics of a particle in external electromagnetic fields. These include additional dissipation terms, the presence of a critical electric field and the power radiated by the particle. The electric effects are sizeable at the fields that are considered attainable with ultrashort TW laser pulses on plasmas.
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...
Self-consistent radiative effect on relativistic electromagnetic particle acceleration
Noguchi, K; Nishimura, K
2005-01-01
We study the radiation damping effect on the relativistic acceleration of electron-positron plasmas with two-and-half-dimensional particle-in-cell (PIC) simulation. Particles are accelerated by Poynting flux via the diamagnetic relativistic pulse accelerator (DRPA), and decelerated by the self-consistently solved radiation damping force. With $\\Omega_{ce}/\\omega_{pe}\\geq 10$, the Lorentz factor of the highest energy particles reaches gamma>100, and the acceleration still continues. The emitted radiation is peaked within few degrees from the direction of Poynting flux and strongly linearly polarized, which may be detectable in gamma-ray burst(GRB) observations. We also show that the DRPA is insensitive to the initial supporting currents.
Solid-particle jet formation under shock-wave acceleration.
Rodriguez, V; Saurel, R; Jourdan, G; Houas, L
2013-12-01
When solid particles are impulsively dispersed by a shock wave, they develop a spatial distribution which takes the form of particle jets whose selection mechanism is still unidentified. The aim of the present experimental work is to study particle dispersal with fingering effects in an original quasi-two-dimensional experiment facility in order to accurately extract information. Shock and blast waves are generated in the carrier gas at the center of a granular medium ring initially confined inside a Hele-Shaw cell and impulsively accelerated. With the present experimental setup, the particle jet formation is clearly observed. From fast flow visualizations, we notice, in all instances, that the jets are initially generated inside the particle ring and thereafter expelled outward. This point has not been observed in three-dimensional experiments. We highlight that the number of jets is unsteady and decreases with time. For a fixed configuration, considering the very early times following the initial acceleration, the jet size selection is independent of the particle diameter. Moreover, the influence of the initial overpressure and the material density on the particle jet formation have been studied. It is shown that the wave number of particle jets increases with the overpressure and with the decrease of the material density. The normalized number of jets as a function of the initial ring acceleration shows a power law valid for all studied configurations involving various initial pressure ratios, particle sizes, and particle materials. PMID:24483561
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.
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.).
Recent Results in Charged-Composite Particle Scattering
Alt, E O
1997-01-01
A brief overview is given of some recent advances in charged-composite particle scattering. On the theoretical side, I address the three-charged particle wave function asymptotics, the nonperturbative investigation of the long-range behaviour of the optical potential, and the question of the compactness of the kernels of the momentum space integral equations for three charged particles. Among the more practical developments, I report on results of numerical calculations of so-called "triangle" amplitudes, a new, simple and very efficient higher-energy approximation for the latter, and a breakthrough in the quantitative treatment of Coulomb effects in proton-deuteron elastic scattering with realistic nuclear potentials.
Quantum interface to charged particles in a vacuum
Okamoto, Hiroshi
2015-11-01
A superconducting qubit device suitable for interacting with a flying electron has recently been proposed [Okamoto and Nagatani, Appl. Phys. Lett. 104, 062604 (2014), 10.1063/1.4865244]. Either a clockwise or counterclockwise directed loop of half magnetic flux quantum encodes a qubit, which naturally interacts with any single charged particle with arbitrary kinetic energy. Here, the device's properties, sources of errors, and possible applications are studied in detail. In particular, applications include detection of a charged particle essentially without applying a classical force to it. Furthermore, quantum states can be transferred between an array of the proposed devices and the charged particle.
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.
Advanced visualization technology for terascale particle accelerator simulations
International Nuclear Information System (INIS)
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
Collisionless Shocks -- Magnetic Field Generation and Particle Acceleration
Frederiksen, J. Trier; Hededal, C. B.; Haugboelle, T.; Nordlund, A.
2003-01-01
We present numerical results from plasma particle simulations of collisionless shocks and ultra-relativistic counter-streaming plasmas. We demonstrate how the field-particle interactions lead to particle acceleration behind the shock-front. Further, we demonstrate how ultra relativistic counter-streaming plasmas create large scale patchy magnetic field structures and that these field structures propagate down-stream of the shock front. These results may help explain the origin of the magnetic...
Spacetime noncommutative effect on black hole as particle accelerators
Ding, Chikun; Liu, Changqing; Qian GUO
2013-01-01
We study the spacetime noncommutative effect on black hole as particle accelerators and, find that particle falling from infinity with zero velocity cannot collide with unbound energy when the noncommutative Kerr black hole is exactly extremal. Our results also show that the bigger of the spinning black hole's mass is, the higher of center of mass energy that the particles obtain. For small and medium noncommutative Schwarzschild black hole, the collision energy depends on the black holes' mass.
Mechanisms of Particle Charging by Surfactants in Nonpolar Dispersions.
Lee, Joohyung; Zhou, Zhang-Lin; Alas, Guillermo; Behrens, Sven Holger
2015-11-10
Electric charging of colloidal particles in nonpolar solvents plays a crucial role for many industrial applications and products, including rubbers, engine oils, toners, or electronic displays. Although disfavored by the low solvent permittivity, particle charging can be induced by added surfactants, even nonionic ones, but the underlying mechanism is poorly understood, and neither the magnitude nor the sign of charge can generally be predicted from the particle and surfactant properties. The conclusiveness of scientific studies has been limited partly by a traditional focus on few surfactant types with many differences in their chemical structure and often poorly defined composition. Here we investigate the surface charging of poly(methyl methacrylate) particles dispersed in hexane-based solutions of three purified polyisobutylene succinimide polyamine surfactants with "subtle" structural variations. We precisely vary the surfactant chemistry by replacing only a single electronegative atom located at a fixed position within the polar headgroup. Electrophoresis reveals that these small differences between the surfactants lead to qualitatively different particle charging. In the respective particle-free surfactant solutions we also find potentially telling differences in the size of the surfactant aggregates (inverse micelles), the residual water content, and the electric solution conductivity as well as indications for a significant size difference between oppositely charged inverse micelles of the most hygroscopic surfactant. An analysis that accounts for the acid/base properties of all constituents suggests that the observed particle charging is better described by asymmetric adsorption of charged inverse micelles from the liquid bulk than by charge creation at the particle surface. Intramicellar acid-base interaction and intermicellar surfactant exchange help rationalize the formation of micellar ions pairs with size asymmetry. PMID:26484617
Test-particle acceleration in a hierarchical three-dimensional turbulence model
Dalena, S; Dmitruk, P; Greco, A; Matthaeus, W H
2014-01-01
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, multi-scale 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 ...
Particle Acceleration at Reconnecting 3D Null Points
Stanier, A.; Browning, P.; Gordovskyy, M.; Dalla, S.
2012-12-01
Hard X-ray observations from the RHESSI spacecraft indicate that a significant fraction of solar flare energy release is in non-thermal energetic particles. A plausible acceleration mechanism for these are the strong electric fields associated with reconnection, a process that can be particularly efficient when particles become unmagnetised near to null points. This mechanism has been well studied in 2D, at X-points within reconnecting current sheets; however, 3D reconnection models show significant qualitative differences and it is not known whether these new models are efficient for particle acceleration. We place test particles in analytic model fields (eg. Craig and Fabling 1996) and numerical solutions to the the resistive magnetohydrodynamic (MHD) equations near reconnecting 3D nulls. We compare the behaviour of these test particles with previous results for test particle acceleration in ideal MHD models (Dalla and Browning 2005). We find that the fan model is very efficient due to an increasing "guide field" that stabilises particles against ejection from the current sheet. However, the spine model, which was the most promising in the ideal case, gives weak acceleration as the reconnection electric field is localised to a narrow cylinder about the spine axis.
Black hole with a scalar field as a particle accelerator
Zaslavskii, O B
2016-01-01
We consider black holes with the background scalar field and test particles that can interact with this field directly. Then, particle collision near a black hole can lead to unbound energy $E_{c.m.}$ in the centre of mass frame (contrary to some recent claims in literature). This happens if one of particles is neutral whereas another one has nonzero scalar charge. Kinematically, two cases occur here. (i) A neutral particle approaches the horizon with the speed of light while the velocity of the charged one remains separated from it (this is direct analogue of the situation with collision of geodesic particles.). (ii) Both particles approach the horizon with the speed almost equal to that of light but with different rates. As a result, in both cases the relative velocity also approaches the speed of light, so that $E_{c.m.}$ $\\ $becomes unbound.
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.
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.
On the possibility of accelerating multiply charged ions in the CERN Synchrocyclotron
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.
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)
Charged particle interaction with a chirped electromagnetic pulse
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.
GPU Accelerated Particle Visualization with Splotch
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...
Analogies between light optics and charged-particle optics
Khan, Sameen Ahmed
2002-01-01
The close analogy between geometrical optics and the classical theories of charged-particle beam optics have been known for a very long time. In recent years, quantum theories of charged-particle beam optics have been presented with the very expected feature of wavelength-dependent effects. With the current development of non-traditional prescriptions of Helmholtz and Maxwell optics respectively, accompanied with the wavelength-dependent effects, it is seen that the analogy between the two sy...
A stochastic model for non-relativistic particle acceleration
Pallocchia, G; Consolini, G
2016-01-01
A stochastic model is proposed for the acceleration of non-relativistic particles yielding to energy spectra with a shape of a Weibull\\textquoteright s function. Such particle distribution is found as the stationary solution of a diffusion-loss equation in the framework of a second order Fermi\\textquoteright s mechanism producing anomalous diffusion for particle velocity. The present model is supported by in situ observations of energetic particle enhancements at interplanetary shocks, as here illustrated by means of an event seen by STEREO B instruments in the heliosphere. Results indicate that the second order Fermi\\textquoteright s mechanism provides a viable explanation for the acceleration of energetic particles at collisioness shock waves.
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 E_{cm} 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/c^{2}. 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.
An improved search for elementary particles with fractional electric charge
International Nuclear Information System (INIS)
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
Noncommutative magnetic moment of charged particles
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.
Observation of high iron charge states at low energies in solar energetic particle events
Energy Technology Data Exchange (ETDEWEB)
Guo, Z.; Möbius, E.; Bochsler, P.; Connell, J. J.; Popecki, M. A. [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); Klecker, B. [Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, D-85741 Garching (Germany); Kartavykh, Y. Y. [Ioffe Physical-Technical Institute, St-Petersburg 194021 (Russian Federation); Mason, G. M., E-mail: zwm2@unh.edu [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States)
2014-04-10
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 (Q {sub Fe}) ∼ 10-14 at low energies E ≤ 0.1 MeV nuc{sup –1}, consistent with their origin from typical corona material at temperatures 1-2 MK. Observed increases of (Q {sub Fe}) up to 20 at energies 0.1-0.5 MeV nuc{sup –1} in impulsive SEPs are attributed to stripping during acceleration. However, Q {sub Fe} > 16 is occasionally found in the solar wind, particularly coming from active regions, in contrast to the exclusively reported (Q {sub Fe}) ≤ 14 for low energy SEPs. Here we report results from a survey of all 89 SEP events observed with Advanced Composition Explorer Solar Energetic Particle Ionic Charge Analyzer (SEPICA) in 1998-2000 for iron charge states augmented at low energy with Solar and Heliospheric Observatory CELIAS suprathermal time-of-flight (STOF). Nine SEP events with (Q {sub Fe}) ≥ 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 (Q {sub Fe}) ∼ 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.
Charged Particle Diffusion in Isotropic Random Static Magnetic Fields
Subedi, P.; Sonsrettee, W.; Matthaeus, W. H.; Ruffolo, D. J.; Wan, M.; Montgomery, D.
2013-12-01
Study of the transport and diffusion of charged particles in a turbulent magnetic field remains a subject of considerable interest. Research has most frequently concentrated on determining the diffusion coefficient in the presence of a mean magnetic field. Here we consider Diffusion of charged particles in fully three dimensional statistically isotropic magnetic field turbulence with no mean field which is pertinent to many astrophysical situations. We classify different regions of particle energy depending upon the ratio of Larmor radius of the charged particle to the characteristic outer length scale of turbulence. We propose three different theoretical models to calculate the diffusion coefficient each applicable to a distinct range of particle energies. The theoretical results are compared with those from computer simulations, showing very good agreement.
Engines of discovery a century of particle accelerators
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 ...
Cyclotron resonant interactions in cosmic particle accelerators
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.
Energy Technology Data Exchange (ETDEWEB)
Hannon, Fay
2016-08-02
A method for maximizing the brightness of the bunches in a particle injector by converting a highly space-charged beam to a relativistic and emittance-dominated beam. The method includes 1) determining the bunch charge and the initial kinetic energy of the highly space-charge dominated input beam; 2) applying the bunch charge and initial kinetic energy properties of the highly space-charge dominated input beam to determine the number of accelerator cavities required to accelerate the bunches to relativistic speed; 3) providing the required number of accelerator cavities; and 4) setting the gradient of the radio frequency (RF) cavities; and 5) operating the phase of the accelerator cavities between -90 and zero degrees of the sinusoid of phase to simultaneously accelerate and bunch the charged particles to maximize brightness, and until the beam is relativistic and emittance-dominated.
A new look at the pushing force of an electromagnetic wave on a classical charged particle
International Nuclear Information System (INIS)
The interaction between a plane wave and a classical charged particle is reviewed in this paper. A matrix formulation is used to derive the relativistic motion of the particle due to the Lorentz force of a spatially homogeneous time-harmonic radiation field. The Landau–Lifshitz approach to the radiation damping force is then investigated for the same field. In conclusion only the radiation damping accelerates the particle in the direction of the Poynting vector for this type of field. The Lorentz force only leads to an extra constant drift velocity, plus oscillations with the frequency of the field. (paper)
Observation of High Iron Charge States at Low Energies in Solar Energetic Particle Events
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.
Particle in cell simulation of laser-accelerated proton beams for radiation therapy
International Nuclear Information System (INIS)
In this article we present the results of particle in cell (PIC) simulations of laser plasma interaction for proton acceleration for radiation therapy treatments. We show that under optimal interaction conditions protons can be accelerated up to relativistic energies of 300 MeV by a petawatt laser field. The proton acceleration is due to the dragging Coulomb force arising from charge separation induced by the ponderomotive pressure (light pressure) of high-intensity laser. The proton energy and phase space distribution functions obtained from the PIC simulations are used in the calculations of dose distributions using the GEANT Monte Carlo simulation code. Because of the broad energy and angular spectra of the protons, a compact particle selection and beam collimation system will be needed to generate small beams of polyenergetic protons for intensity modulated proton therapy
An introduction to acceleration mechanisms
International Nuclear Information System (INIS)
This paper discusses the acceleration of charged particles by electromagnetic fields, i.e., by fields that are produced by the motion of other charged particles driven by some power source. The mechanisms that are discussed include: Ponderamotive Forces, Acceleration, Plasma Beat Wave Acceleration, Inverse Free Electron Laser Acceleration, Inverse Cerenkov Acceleration, Gravity Acceleration, 2D Linac Acceleration and Conventional Iris Loaded Linac Structure Acceleration
Particle accelerators unravel Art and Archaeology issues
Calligaro, Thomas
2008-10-01
Many analytical techniques are applied to get a better insight on art works and archaeological artefacts and to contribute to their conservation and restoration. Because of the precious and sometimes unique character of these items, non-destructive and non-sampling techniques are preferred. From this standpoint, the analysis with ion beams produced by accelerators (IBA), featuring good analytical performance and non-destructiveness, constitutes one of the best choices. Ion beams analysis techniques (IBA) introduced in 1957 have been constantly adapted to address art and archaeology questions; today the performances obtained directly on the object placed in the atmosphere rival with those achieved in vacuum. Since 20 years, AGLAE, the IBA facility of the Centre for Research and Restoration of the Museums of France located in the Louvre museum has contributed to this progress. The cornerstone of this development is a versatile external nuclear microprobe implementing PIXE, PIGE, RBS, NRA and ERDA methods for rapid expertises of art works and more extensive research works in art history, archaeology and conservation science. After an introduction of the physical principles of IBA, a virtual tour of this unique facility will be provided. The benefit of its use will be illustrated through two case studies, the first one dealing with the determination by PIXE of the provenance of painted works of the Spanish master Murillo and the second one with the authentication study using NRA of a mysterious archaeological rock crystal skull.
Technical training: AXEL-2012 - Introduction to Particle Accelerators
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 ...
The acceleration of particles in the vicinity of comets
International Nuclear Information System (INIS)
The various processes capable of accelerating ions in the vicinity of comets as part of the comet/solar wind interaction are considered. It is concluded that the most important are ion pick-up, adiabatic compresses and second order Fermi acceleration in the turbulence associated with the interaction. Model particle spectra are calculated on the assumption that the turbulence is dominated by Alfven waves, and it is shown that the peak associated with ion pick-up remains a distinct feature of the spectrum despite spreading to higher and lower energies. Diffusive shock acceleration and magnetic field reconnection are shown to be relatively unimportant in producing energetic ions. (author)
Stochastic acceleration and charge change of helium ions in the solar flare plasma.
Kartavykh, Yu. Yu.; Ostryakov, V. M.; Stepanov, I. Yu.; Yoshimori, M.
1998-10-01
In order to explain the energy spectra and abundances of the He+ and He++ solar flare ions measured in some works, the authors calculated the behavior of these ions in solar plasma, taking into account both their stochastic acceleration by Alfvén waves and the possibility of charge exchange with the surrounding plasma. The results agree with the experiments if the plasma in the regions where acceleration takes place has a concentration and temperature on the order of N = 2×107 cm-3 and T = 6.31×104K, respectively. Recent observations of solar flares onboard the Yohkoh satellite have demonstrated that it is apparently impractical to expect the existence of such rarefied and low-temperature plasma in the flare loops. The calculations indicate that the high abundance of He+ is most likely due to its nonsolar origin. Some possibilities of enrichment of energetic particle fluxes by He+ ions are briefly discussed.
Exploring Particle Acceleration in Gamma-Ray Binaries
Bosch-Ramon, V.; Rieger, F. M.
2012-08-01
Binary systems can be powerful sources of non-thermal emission from radio to gamma rays. When the latter are detected, then these objects are known as gamma ray binaries. In this work, we explore, in the context of gamma ray binaries, different acceleration processes to estimate their efficiency: Fermi I, Fermi II, shear acceleration, the converter mechanism, and magnetic reconnection. We find that Fermi I acceleration in a mildly relativistic shock can provide, although marginally, the multi-10 TeV particles required to explain observations. Shear acceleration may be a complementary mechanism, giving particles the final boost to reach such a high energies. Fermi II acceleration may be too slow to account for the observed very high energy photons, but may be suitable to explain extended low-energy emission. The converter mechanism seems to require rather high Lorentz factors but cannot be discarded a priori. Standard relativistic shock acceleration requires a highly turbulent, weakly magnetized downstream medium; magnetic reconnection, by itself possibly insufficient to reach very high energies, could perhaps facilitate such a conditions. Further theoretical developments, and a better source characterization, are needed to pinpoint the dominant acceleration mechanism, which need not be one and the same in all sources.
Charge Balance in the Mesosphere with Meteoric Dust Particles
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.
Determination of Beam Intensity and Position in a Particle Accelerator
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...
Determination of beam intensity and position in a particle accelerator
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...
An update on (n,charged particle) research at WNR
Energy Technology Data Exchange (ETDEWEB)
Haight, R.C.; Bateman, F.B.; Sterbenz, S.M. [Los Alamos National Lab., NM (United States); Grimes, S.M. [Ohio Univ., Athens, OH (United States); Wasson, O.A. [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Maier-Komor, P. [T.U. Munich (Germany); Vonach, H. [Inst. fuer Radiumforschung und Kernphysik, Vienna (Austria)
1995-12-31
Neutron-induced reactions producing light charged particles continue to be investigated at the spallation fast-neutron source at the Los Alamos Neutron Science Center (LANSCE). New data on the cross sections for alpha-particle production for neutrons on {sup 58}Ni and {sup 60}Ni are presented from threshold to 50 MeV. Recent changes in the experiment now allow protons, deuterons, tritons, {sup 3}He and alpha particles to be identified.
An update on (n,charged particle) research at WNR
International Nuclear Information System (INIS)
Neutron-induced reactions producing light charged particles continue to be investigated at the spallation fast-neutron source at the Los Alamos Neutron Science Center (LANSCE). New data on the cross sections for alpha-particle production for neutrons on 58Ni and 60Ni are presented from threshold to 50 MeV. Recent changes in the experiment now allow protons, deuterons, tritons, 3He and alpha particles to be identified
Change in surface of polymer materials upon irradiation of accelerated micro-particles
Energy Technology Data Exchange (ETDEWEB)
Kudo, Hisaaki [Nuclear Engineering Research Laboratory, School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Ibaraki 319-1188 (Japan)]. E-mail: hkudo@utnl.jp; Tadokoro, Masashi [Nuclear Engineering Research Laboratory, School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Ibaraki 319-1188 (Japan); Narita, Shintaro [Nuclear Engineering Research Laboratory, School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Ibaraki 319-1188 (Japan); Matsuoka, Leo [Nuclear Engineering Research Laboratory, School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Ibaraki 319-1188 (Japan); Muroya, Yusa [Nuclear Engineering Research Laboratory, School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Ibaraki 319-1188 (Japan); Katsumura, Yosuke [Nuclear Engineering Research Laboratory, School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Ibaraki 319-1188 (Japan)
2005-07-01
As a new method of use of a particle accelerator (ionizing radiation generator), we irradiated accelerated micro-particles of silver (Ag) onto polymer materials such as polyimides, glass, ceramics and semi-conductors. The particles can be generated at a Van de Graaff electrostatic accelerator operating at 1-3 MV. The velocity was around 1-10 km/s, size of diameter was about 1-10 {mu}m and charge was about 1-2 {mu}C. We investigated the change in surface of materials upon irradiation, by using laser microscope, atomic force microscope and scanning electron microscope. Crater-shaped irradiation spots having limb structure were found, and their diameter and depth were evaluated, ranging in a few micrometers. The planar distribution of the projectile around the irradiation spot was examined with energy dispersive X-ray spectroscopy. Correlation between size of the irradiation spots and kinetic energy of the accelerated micro-particles was investigated, and compared with an empirical formula and molecular dynamics study. Numerical simulation dealing with dynamic behaviour of elastic structure was carried out based on SPH (Smoothed Particle Hydrodynamics) method, a kind of (virtual) particle method. The simulation also found that a crater-shaped spot having limb structure is formed upon collision of the accelerated projectile with the target-materials. The results of simulation were compared with the experimental observations. These experiment and simulation are important for the evaluation of damages and resistance of polymer materials used in the space, such as the thermal control material, and cover glass of solar cells etc., towards space debris and dusts. It would be complement the on-ground radiation resistant tests on the materials conducted by using electron and ion beam accelerators.
Beam optics and lattice design for particle accelerators
Holzer, Bernhard J.
2013-01-01
The goal of this manuscript is to give an introduction into the design of the magnet lattice and as a consequence into the transverse dynamics of the particles in a synchrotron or storage ring. Starting from the basic principles of how to design the geometry of the ring we will briefly review the transverse motion of the particles and apply this knowledge to study the layout and optimization of the principal elements, namely the lattice cells. The detailed arrangement of the accelerator magne...
Doubly-charged particles at the Large Hadron Collider
Alloul, Adam; Fuks, Benjamin; de Traubenberg, Michel Rausch
2013-01-01
In this work we investigate the production and signatures of doubly-charged particles at the Large Hadron Collider. We start with the Standard Model particle content and representations and add generic doubly-charged exotic particles. We classify these doubly-charged states according to their spin, considering scalar, fermionic and vectorial fields, and according to their SU(2)L representation, being chosen to be either trivial, fundamental, or adjoint. We write the most general interactions between them and the Standard Model sector and study their production modes and possible decay channels. We then probe how they can most likely be observed and how particles with different spin and SU(2)L representations could be possibly distinguished.
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.)
Atmosphere turbulence effect on the hot particle charge
International Nuclear Information System (INIS)
The charging of hot beta-active aerosol articles of the micron size range in the turbulent current has been studied experimentally . For this purpose hot particles, obtained by the neutron activation of gold placed on the surface of glass microspheres by the cathode spraying method, were introduced into the turbulent current with the Reynolds number of 104 - 105. Results of the determination of particle charges within the current velocity range from 0.5 to 3 m/s confirm the reliability of the previously obtained model of the charging of hot particles in the turbulent current of the near - ground atmospere layer which is described by the function directly proportional to the radius of particles and the half-cube of the wind velocity, and inversely proportional to the square root of the height. The scheme is suggested and specific features are described of experimental installations used in the process of studies
50 years of research on particle acceleration in the heliosphere
Fisk, L. A.
2015-09-01
In 1965, and through the late 1960s, the heliosphere was considered to be a passive place, an impediment to the information on the galaxy contained in galactic cosmic ray observations, and on the Sun, from solar energetic particles. All this changed in the early 1970s with the discovery of the Anomalous Cosmic Rays (ACRs), and the subsequent acceptance that the ACRs are ionized interstellar neutral gas that is accelerated in the heliosphere by four orders of magnitude in energy. In the mid-1970s, Pioneer 10 & 11 observations provided direct evidence of acceleration. In 1977-78, diffusive shock acceleration was introduced, and subsequently developed in detail, providing compelling explanations for, e.g., the observed acceleration in co-rotating interaction regions, and a likely explanation for the acceleration of ACRs at the termination shock of the solar wind. In 2004 and 2008, the Voyagers crossed the termination shock, did not observe the acceleration of the ACRs, but did observe that low- energy particles, up to a few MeV/nucleon, had identical spectra downstream from the termination shock, a distribution function that is a power law in particle speed with a spectral index of -5. When Voyager 1 reached ∼120 AU, where the high-energy ACRs are at peak intensity, the ACR spectrum is also a -5 spectrum. Moreover, observations of suprathermal tails in the solar wind in the inner solar system have a -5 spectrum, often peaking downstream, but not at shocks. These observations led to the development of a new acceleration mechanism, the pump acceleration mechanism of Fisk & Gloeckler, which can account for all the observed -5 spectra.
DiFabio, R.; Guo, Z.; Möbius, E.; Klecker, B.; Kucharek, H.; Mason, G. M.; Popecki, M.
2008-11-01
Impulsive solar energetic particle (SEP) events show substantial enhancements of heavy ions and 3He over the composition in the Sun's atmosphere. Mass per charge dependent acceleration mechanisms have been proposed to account for this preferential acceleration. However, a problem emerged for all the preferential acceleration models with the measurement of ionization states near 1 MeV nucleon-1, which showed that ions from C to Mg are fully stripped, a challenge that had been recognized early on. Since all models relied on differences in the charge-to-mass ratio to enable preferential acceleration, the proposed mechanisms were incompatible with this observation. Recent observations of the ionic charge states at lower energies have revealed a dependence on energy, with the charge states decreasing for lower energy ions. This raises the possibility that the low-energy charge states reflect the plasma conditions at the acceleration site, while the high-energy charge states are due to stripping low in the solar corona. In a survey of impulsive events we show that the increase of the Fe charge states with energy is highly significant for the sample of events and thus most likely a general feature of impulsive events. To see whether there is a connection between the enhancements and charge states, we extended the ACE SEPICA charge-state observations to lower energies and combined them with the ion fluxes from ACE ULEIS for impulsive events observed between 1997 and 2000. We find a positive correlation between the abundance ratios and the charge states at low energy, while the charge states at the highest energy do not demonstrate such dependence. This supports the idea that the higher mass particles are preferentially accelerated before being stripped.
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 ~ 10^{9} 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.
Relativistic mixtures of charged and uncharged particles
Kremer, Gilberto M.
2014-01-01
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.
Tracking parameter simulation for the Turkish accelerator center particle factory tracker system
Tapan, I.; Pilicer, E.; Pilicer, F. B.
2016-09-01
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.
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.
Particle Acceleration at Relativistic and Ultra-Relativistic Shock Waves
Meli, A.
We perform Monte Carlo simulations using diffusive shock acceleration at relativistic and ultra-relativistic shock waves. High upstream flow gamma factors are used, Γ=(1-uup2/c2)-0.5, which are relevant to models of ultra-relativistic particle shock acceleration in the central engines and relativistic jets of Active Galactic Nuclei (AGN) and in Gamma-Ray Burst (GRB) fireballs. Numerical investigations are carried out on acceleration properties in the relativistic and ultra-relativistic flow regime (Γ ˜ 10-1000) concerning angular distributions, acceleration time scales, particle energy gain versus number of crossings and spectral shapes. We perform calculations for both parallel and oblique sub-luminal and super-luminal shocks. For parallel and oblique sub-luminal shocks, the spectra depend on whether or not the scattering is represented by pitch angle diffusion or by large angle scattering. The large angle case exhibits a distinctive structure in the basic power-law spectrum not nearly so obvious for small angle scattering. However, both cases yield a significant 'speed-up' of acceleration rate when compared with the conventional, non-relativistic expression, tacc=[c/(uup-udown)] (λup/uup+λdown/udown). An energization by a factor Γ2 for the first crossing cycle and a large energy gains for subsequent crossings as well as the high 'speed-up' factors found, are important in supporting past works, especially the models developed by Vietri and Waxman on ultra-high energy cosmic ray, neutrino and gamma-ray production in GRB. For oblique super-luminal shocks, we calculate the energy gain and spectral shape for a number of different inclinations. For this case the acceleration of particles is 'pictured' by a shock drift mechanism. We use high gamma flows with Lorentz factors in the range 10-40 which are relevant to ultra-relativistic shocks in AGN accretion disks and jets. In all investigations we closely follow the particle's trajectory along the magnetic field
JMS-based SOA monitors CERN particle accelerators
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)
Big magnet glitch at world's top particle accelerator
Weiss, Giselle
2007-01-01
"Officials at CERN, near Geneva, believe they have found a solution to the latest hitch in the construction of the Large Hadron Collider (LHC), a state-of-the-art particle accelerator that straddles the Franco-Swiss border." (1 page)
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...
Diffusiophoretic mobility of charge-regulating porous particles.
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.
Cryogenic Beam Screens for High-Energy Particle Accelerators
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...
Borkovec, Michal; Szilagyi, Istvan; Popa, Ionel; Finessi, Marco; Sinha, Prashant; Maroni, Plinio; Papastavrou, Georg
2012-11-01
Direct force measurements are used to obtain a comprehensive picture of interaction forces acting between charged colloidal particles in the presence of oppositely charged polyelectrolytes. These measurements are achieved by the multi-particle colloidal probe technique based on the atomic force microscope (AFM). This novel extension of the classical colloidal probe technique offers three main advantages. First, the technique works in a colloidal suspension with a huge internal surface area of several square meters, which simplifies the precise dosing of the small amounts of the polyelectrolytes needed and makes this approach less sensitive to impurities. Second, the particles are attached in-situ within the fluid cell, which avoids the formation of nanobubbles on the latex particles used. Third, forces between two similar particles from the same batch are being measured, which allows an unambiguous determination of the surface potential due to the symmetry of the system. Based on such direct force measurements involving positively and negatively charged latex particles and different polyelectrolytes, we find the following forces to be relevant. Repulsive electrostatic double-layer forces and attractive van der Waals forces as described by the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) are both important in these systems, whereby the electrostatic forces dominate away from the isoelectric point (IEP), while at this point they vanish. Additional non-DLVO attractive forces are operational, and they have been identified to originate from the electrostatic interactions between the patch-charge heterogeneities of the adsorbed polyelectrolyte films. Highly charged polyelectrolytes induce strong patch-charge attractions, which become especially important at low ionic strengths and high molecular mass. More weakly charged polyelectrolytes seem to form more homogeneous films, whereby patch-charge attractions may become negligible. Individual bridging events
Spacetime Noncommutative Effect on Black Hole as Particle Accelerators
Ding, Chikun; Liu, Changqing; Quo, Qian
2013-03-01
We study the spacetime noncommutative effect on black hole as particle accelerators and, find that the particles falling from infinity with zero velocity cannot collide with unbound energy, either near the horizon or on the prograde ISCO when the noncommutative Kerr black hole is exactly extremal. Our results also show that the bigger of the spinning black hole's mass is the higher of center of mass energy that the particles obtain. For small and medium noncommutative Schwarzschild black hole, the collision energy depends on the black hole's mass.
Acceleration and Radiation Model of Particles in Solar Active Regions
Anastasiadis, Anastasios; Dauphin, Cyril; Vilmer, Nicole
2006-08-01
Cellular Automata (CA) models have successfully reproduced several statistical properties of solar flares such as the peak flux or the total flux distribution. We are using a CA model based on the concept of self organized criticality (SOC) to model the evolution of the magnetic energy released in a solar flare. Each burst of magnetic energy released is assumed to be the consequence of a magnetic reconnection process, where the particles are accelerated by a direct electric field. We relate the difference of energy gain of particles (alpha particles, protons and electrons) to the magnetic energy released and we calculate the resulting kinetic energy distributions and the emitted radiation.
Particle acceleration, magnetization and radiation in relativistic shocks
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.
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.
Barletta, William A.
2009-03-01
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, cross-disciplinary research areas such as high energy density physics.
International Nuclear Information System (INIS)
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, cross-disciplinary research areas such as high energy density physics.
Technical training: AXEL-2008 - Introduction to Particle Accelerators
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...
Charged particle reaction cross sections and nucleosynthesis
International Nuclear Information System (INIS)
The role of proton and α-particle induced reactions in carbon, neon, oxygen and silicon burning in massive stars is surveyed. The problems associated with determining thermonuclear reaction rates for reactions with widely spaced resonances and with closely spaced or overlapping resonances are discussed and the associated experimental approaches are reviewed. Experimental techniques which have been used in the measurement of reaction cross sections are discussed and their strengths and weaknesses are identified. Recent developments in attempts to establish reliable statistical-model codes for calculation of reaction cross sections are presented and discussed. The results of experimental tests of statistical model codes are summarised and evaluated
Solar release time of solar energetic particles and associated acceleration source in corona
Institute of Scientific and Technical Information of China (English)
无
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.
Extreme particle acceleration in the microquasar Cygnus X-3.
Tavani, M; Bulgarelli, A; Piano, G; Sabatini, S; Striani, E; Evangelista, Y; Trois, A; Pooley, G; Trushkin, S; Nizhelskij, N A; McCollough, M; Koljonen, K I I; Pucella, G; Giuliani, A; Chen, A W; Costa, E; Vittorini, V; Trifoglio, M; Gianotti, F; Argan, A; Barbiellini, G; Caraveo, P; Cattaneo, P W; Cocco, V; Contessi, T; D'Ammando, F; Del Monte, E; De Paris, G; Di Cocco, G; Di Persio, G; Donnarumma, I; Feroci, M; Ferrari, A; Fuschino, F; Galli, M; Labanti, C; Lapshov, I; Lazzarotto, F; Lipari, P; Longo, F; Mattaini, E; Marisaldi, M; Mastropietro, M; Mauri, A; Mereghetti, S; Morelli, E; Morselli, A; Pacciani, L; Pellizzoni, A; Perotti, F; Picozza, P; Pilia, M; Prest, M; Rapisarda, M; Rappoldi, A; Rossi, E; Rubini, A; Scalise, E; Soffitta, P; Vallazza, E; Vercellone, S; Zambra, A; Zanello, D; Pittori, C; Verrecchia, F; Giommi, P; Colafrancesco, S; Santolamazza, P; Antonelli, A; Salotti, L
2009-12-01
Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated gamma-ray emission. Galactic 'microquasars', which are binary systems consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares. Apart from an isolated event detected in Cygnus X-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four gamma-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 (an exceptional X-ray binary that sporadically produces radio jets). There is a clear pattern of temporal correlations between the gamma-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In Cygnus X-3, particle energies during the flares can be thousands of times higher than during quiescent states. PMID:19935645
Acceleration PDFs of particles in rotating turbulent convection
Clercx, Herman; Perlekar, Prasad; Lavezzo, Valentina; Toschi, Federico
2012-11-01
Particle dispersion in buoyancy-driven rotating turbulent flows has direct relevance for many industrial and environmental applications. We have used a Lattice Boltzmann Method coupled with Lagrangian particle tracking algorithm to investigate the behaviour of passive and inertial particles released in turbulent rotating Rayleigh-Bénard (RB) convection. The flow domain is horizontally periodic and vertically confined. Both the gravity and the rotation vector are oriented in the vertical direction. Here we present the results of the acceleration PDFs of particles in both non-rotating and strongly rotating RB convection. It is found that the bulk acceleration PDF in non-rotating RB turbulence is like in homogeneous isotropic turbulence whereas rotation introduces anisotropy similar to acceleration PDFs obtained from experiments in (isothermal) forced rotating turbulence. These results and those obtained for inertial particles will be discussed. PP and VL were financially supported by the Foundation for Fundamental Research on Matter (FOM), which is part of NWO. This work was sponsored by NWO-NCF (SH-176).
Electric birefringence anomaly of solutions of ionically charged anisometric particles.
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
On the novel mechanism of acceleration of cosmic particles
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...
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.
Medical radiation dosimetry theory of charged particle collision energy loss
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...
Charged-Particle Multiplicity in Proton-Proton Collisions
Grosse-Oetringhaus, Jan Fiete
2010-01-01
This article summarizes and critically reviews measurements of charged-particle multiplicity distributions and pseudorapidity densities in p+p(pbar) collisions between sqrt(s) = 23.6 GeV and sqrt(s) = 1.8 TeV. Related theoretical concepts are briefly introduced. Moments of multiplicity distributions are presented as a function of sqrt(s). Feynman scaling, KNO scaling, as well as the description of multiplicity distributions with a single negative binomial distribution and with combinations of two or more negative binomial distributions are discussed. Moreover, similarities between the energy dependence of charged-particle multiplicities in p+p(pbar) and e+e- collisions are studied. Finally, various predictions for pseudorapidity densities, average multiplicities in full phase space, and multiplicity distributions of charged particles in p+p(pbar) collisions at the LHC energies of sqrt(s) = 7 TeV, 10 TeV, and 14 TeV are summarized and compared.
Electromagnetic radiation of charged particles in stochastic motion
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 ...
The use of heavy charged particles in the radiation therapy of tumors
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...
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.
Charged Massive Particle's Tunneling From Charged Non-Rotating Micro Black Hole
Soleimani, M J; Radiman, Shahidan; Abdullah, W A T Wan
2015-01-01
In the tunneling framework of Hawking radiation, charged massive particle's tunneling in charged non-rotating TeV-Scale black hole is investigated. To this end, we consider natural cutoffs as a minimal length, a minimal momentum, and a maximal momentum through a generalized uncertainty principle. We focus on the role played by these natural cutoffs on the luminosity of charged non-rotating micro black hole by taking into account the full implications of energy and charge conservation as well as the back- scattered radiation.
Mass, charge, and energy separation by selective acceleration with a traveling potential hill
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
Compact formulae, dynamics and radiation of charged particles under synchro-curvature losses
Viganò, Daniele; Hirotani, Kouichi; Pessah, Martín E
2014-01-01
We consider the fundamental problem of charged particles moving along and around a curved magnetic field line, revising the synchro-curvature radiation formulae introduced by Cheng and Zhang (1996). We provide more compact expressions to evaluate the spectrum emitted by a single particle, identifying the key parameter that controls the transition between the curvature-dominated and the synchrotron-dominated regime. This parameter depends on the local radius of curvature of the magnetic field line, the gyration radius, and the pitch angle. We numerically solve the equations of motion for the emitting particle by considering self-consistently the radiative losses, and provide the radiated spectrum produced by a particle when an electric acceleration is balanced by its radiative losses, as it is assumed to happen in the outer gaps of pulsar's magnetospheres. We compute the average spectrum radiated throughout the particle trajectory finding that the slope of the spectrum before the peak depends on the location a...
Stochastic Particle Acceleration in Turbulence Generated by Magnetorotational Instability
Kimura, Shigeo S.; Toma, Kenji; Suzuki, Takeru K.; Inutsuka, Shu-ichiro
2016-05-01
We investigate stochastic particle acceleration in accretion flows. It is believed that 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 and without back reaction to the field. Our results show that the CRs randomly gain or lose their energy through interaction with the turbulent fields. The CRs diffuse in the configuration space anisotropically: the diffusion coefficient in the direction of the unperturbed flow is about 20 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 works efficiently for energetic particles. We also cautiously note that in the shearing box approximation, particles that cross the simulation box many times along the radial direction undergo unphysical runaway acceleration by the Lorentz transformation, which needs to be taken into account with special care.
Shock Acceleration and Transport of Solar Energetic Particles in the Corona
Ng, C. K.; Ko, Y.; Tylka, A. J.; von Rosenvinge, T. T.
2013-12-01
In gradual solar energetic particle (SEP) events, the phase-space density of suprathermal seed particles plays an important role in the bootstrap acceleration of SEPs at a coronal-mass-ejection driven shock in the corona. Higher seed proton density causes more rapid resonant amplification of ambient Alfvén waves and hence faster shock acceleration of SEPs. On the other hand, SEP-driven Alfvén wave growth is slowed by higher plasma density and by the thermal damping of left-hand polarized waves at frequencies exceeding a fraction of the proton cyclotron frequency. Damping also influences the background wave distribution. Coronal magnetic field strongly influences the wave-particle interaction since its magnitude scales the resonant wavenumber and its negative parallel gradient focuses the charged particles. The solar-wind velocity and Alfvén speed, relevant to the height of shock formation, are related to the plasma density and magnetic field. Consequently, the spatial dependences of all these environmental parameters influence the coupled evolution of SEP and Alfvén wave distributions. We will present results from our models of SEP acceleration and transport combining the effects of the above physical considerations. The model results will be compared to directly observed and inferred features of SEP events (e.g. streaming-limited intensity, maximum energy, height of first solar particle release) to address the roles and relative importance of the above physical factors.
Particle acceleration, magnetization and radiation in relativistic shocks
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...
Clustering of settling charged particles in turbulence: theory and experiments
Energy Technology Data Exchange (ETDEWEB)
Lu Jiang; Nordsiek, Hansen; Shaw, Raymond A, E-mail: rashaw@mtu.edu [Department of Physics, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)
2010-12-15
Atmospheric clouds, electrosprays and protoplanetary nebula (dusty plasma) contain electrically charged particles embedded in turbulent flows, often under the influence of an externally imposed, approximately uniform gravitational or electric force. We have developed a theoretical description of the dynamics of such systems of charged, sedimenting particles in turbulence, allowing radial distribution functions (RDFs) to be predicted for both monodisperse and bidisperse particle size distributions. The governing parameters are the particle Stokes number (particle inertial time scale relative to turbulence dissipation time scale), the Coulomb-turbulence parameter (ratio of Coulomb 'terminal' speed to the turbulence dissipation velocity scale) and the settling parameter (the ratio of the gravitational terminal speed to the turbulence dissipation velocity scale). The theory is compared to measured RDFs for water particles in homogeneous, isotropic air turbulence. The RDFs are obtained from particle positions measured in three dimensions using digital holography. The measurements verify the general theoretical expression, consisting of a power law increase in particle clustering due to particle response to dissipative turbulent eddies, modulated by an exponential electrostatic interaction term. Both terms are modified as a result of the gravitational diffusion-like term, and the role of 'gravity' is explored by imposing a macroscopic uniform electric field to create an enhanced, effective gravity.
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....
Resonance, particle dynamics, and particle transmission in the micro-accelerator platform
International Nuclear Information System (INIS)
We describe particle dynamics in the Micro-Accelerator Platform (MAP), a slab-symmetric dielectric laser accelerator (DLA), and model the expected performance of recently fabricated MAP structures. The quality of the structure resonances has been characterized optically, and results are compared with simulation. 3D trajectory analysis is used to model acceleration in those same structures “as built.” Results are applied to ongoing beam transmission and acceleration tests at NLCTA/E-163, in which transmission of 60 MeV injected electrons through the beam channel of the MAP was clearly observed, despite the overfilling of the structure by the beam.
Final Report - Interaction of radiation and charged particles in miniature plasma structures
Energy Technology Data Exchange (ETDEWEB)
Antonsen, Thomas M.
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.
Particle acceleration, transport and turbulence in cosmic and heliospheric physics
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.
Physics of high energy particle accelerators. AIP conference proceedings No. 127
International Nuclear Information System (INIS)
Topics covered in this workshop include accelerator physics, particle physics, and new acceleration methods. Eighteen lectures were presented. Individual abstracts were prepared separately for the data base
Universal behavior of charged particle production in heavy ion collisions
Phobos Collaboration; Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.
2003-03-01
The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.
Particle Acceleration in Relativistic Magnetized Collisionless Electron-Ion Shocks
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...
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.
Support vector machine based on adaptive acceleration particle swarm optimization.
Abdulameer, Mohammed Hasan; Sheikh Abdullah, Siti Norul Huda; Othman, Zulaiha Ali
2014-01-01
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. PMID:24790584
Fast magnetic reconnection and particle acceleration in pair plasmas
Bessho, Naoki; Bhattacharjee, A.
2009-11-01
Magnetic reconnection without a guide field in both non-relativistic and relativistic regimes has been studied in pair plasmas by 2D PIC simulations. We have found that in both regimes, particle acceleration enhances reconnection rates by an interesting feedback effect. Reconnection rates in the impulsive phase become of the order of 1 when the background density in a Harris sheet equilibrium is of the order of 0.01 of the density in the current sheet. Fast reconnection becomes possible not only because of increase of the time derivative part of the inertial term in the generalized Ohm's law, but also by a positive feedback on the pressure tensor term, bootstrapped by particle acceleration that produces a reduction in the particle density in the diffusion region. In this impulsive phase, the extension of the diffusion region along the outflow region is accompanied by a broadening of the width of the current sheet in the inflow region, keeping the aspect ratio small and sustaining a large reconnection rate. The collisionless resistivity originating from non-ideal terms in the generalized Ohm's law becomes large and nearly spatially uniform along the diffusion region even after the extension of the diffusion region, and can account quantitatively for the fast reconnection rate. We will compare and contrast this with reconnection and particle acceleration in hydrogen plasmas.
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.
Automatic beam path analysis of laser wakefield particle acceleration data
Energy Technology Data Exchange (ETDEWEB)
Ruebel, Oliver; Wu, Kesheng; Prabhat; Weber, Gunther H; Ushizima, Daniela M; Hamann, Bernd; Bethel, Wes [Computational Research Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Geddes, Cameron G R; Cormier-Michel, Estelle [LOASIS program of Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Messmer, Peter [Tech-X Corporation, 5621 Arapahoe Avenue Suite A, Boulder, CO 80303 (United States); Hagen, Hans [International Research Training Group ' Visualization of Large and Unstructured Data Sets-Applications in Geospatial Planning, Modeling, and Engineering' , Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse, D-67653 Kaiserslautern (Germany)], E-mail: oruebel@lbl.gov
2009-01-01
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 has been 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.
Particle acceleration and gamma-emission from solar flares
Miroshnichenko, Leonty; Gan, W. Q.; Troitskaia, E. V.
Experiments on SMM, Yohkoh, GRANAT, Compton GRO, INTEGRAL, RHESSI and CORONAS-F satellites over the past three decades have provided copious data for fundamental research relating to particle acceleration, transport and energetics in flares and to the ambient abun-dance of the corona, chromosphere and photosphere. We summarize main results of solar gamma-astronomy and try to appraise critically a real contribution of those results into modern understanding of solar flares, particle acceleration at the Sun and some properties of the solar atmosphere. Recent findings based on the RHESSI, INTEGRAL and CORONAS-F measure-ments (source locations, spectrum peculiarities, 3He abundance etc.) are especially discussed. Some unusual features of extreme solar events have been found in gamma-ray production and generation of relativistic particles (solar cosmic rays). A number of different plausible assump-tions are considered concerning the details of underlying physical processes during large flares: existence of a steeper distribution of surrounding medium density, enhanced content of the 3He isotope, formation of magnetic trap with specific properties etc. Possible implications of these results are briefly discussed. It is emphasized that real progress in this field may be achieved only by combination of gamma-ray data in different energy ranges with multi-wave and ener-getic particle observations during the same event. We especially note several promising lines for the further studies: 1) resonant acceleration of the 3He ions in the corona; 2) timing of the flare evolution by gamma-ray fluxes in energy range above 90 MeV; 3) separation of gamma-ray fluxes from different sources at/near the Sun (e.g., different acceleration sources/episodes during the same flare, contribution of energetic particles accelerated by the CME-driven shocks etc.); 4) modeling of self-consistent time scenario of the event. Keywords: Sun: atmosphere density, solar flares; Particle acceleration
Generation of narrow peaks in spectroscopy of charged particles
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.
Construction of asymptotic fields for a charged particle
Greenberg, O. W.; Cowen, Steve
2012-01-01
Asymptotic fields do not exist in theories with massless particles and fields, because the vacuum matrix elements of products of the interacting fields in such theories do not have delta function or principal value singularities in momentum space. We remedy this problem by constructing a field for the charged particle that does have the required singularities in momentum space. We illustrate this construction in quantum electrodynamics (QED).
A composite bolometer as a charged-particle spectrometer
International Nuclear Information System (INIS)
An improved version of a He-cooled composite diamond bolometer with a monolithic germanium thermistor, for use as a charged-particle spectrometer, is described. The performance of the bolometer was tested using 5-6 MeV α particles, and a full-width-at-half-maximum of 36 keV was obtained at 1.3 K. (U.K.)
Acceleration-Extended Galilean Symmetries with Central Charges and their Dynamical Realizations
Lukierski, J.; Stichel, P. C.; Zakrzewski, W. J.
2007-01-01
We add to Galilean symmetries the transformations describing constant accelerations. The corresponding extended Galilean algebra allows, in any dimension $D=d+1$, the introduction of one central charge $c$ while in $D=2+1$ we can have three such charges: c, \\theta and \\theta'. We present nonrelativistic classical mechanics models, with higher order time derivatives and show that they give dynamical realizations of our algebras. The presence of central charge $c$ requires the acceleration squa...
Extreme Particle Acceleration via Magnetic Reconnection in the Crab Nebula
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.
Cosmic-ray acceleration by stellar winds. 2. The spectrum of accelerated particles
International Nuclear Information System (INIS)
The transport equation for the acceleration and modulation of particles of momentum p in a steady spherically symmetric stellar wind with a shock transition at R from speed V1 to speed V2R2/r2 at r>R, and in which energetic particles have spatial diffusion coefficient K1=V1r/eta1 and K2=V2r/eta2 outside the shock, has been solved as closed functions of p, r and the model parameters V1/V2, eta1 and eta2. The source of particles is a function of momentum at r >> R. Specific cases of monoenergetic and truncated power laws are computed. Energy losses and convective modulation compete with acceleration at the shock so effectively in this model that enhancement of the background cosmic-ray flux by more than a factor of 2 is extremely unlikely
AKR breakup and auroral particle acceleration at substorm onset
Morioka, A.; Miyoshi, Y.; Tsuchiya, F.; Misawa, H.; Yumoto, K.; Parks, G. K.; Anderson, R. R.; Menietti, J. D.; Donovan, E. F.; Honary, F.; Spanswick, E.
2008-09-01
The dynamical behavior of auroral kilometric radiation (AKR) is investigated in connection with auroral particle acceleration at substorm onsets using high-time-resolution wave spectrograms provided by Polar/PWI electric field observations. AKR develops explosively at altitudes above a preexisting low-altitude AKR source at substorm onsets. This "AKR breakup" suggests an abrupt formation of a new field-aligned acceleration region above the preexisting acceleration region. The formation of the new acceleration region is completed in a very short time (amplitude increases 10,000 times in 30 seconds), suggesting that the explosive development is confined to a localized region. AKR breakups are usually preceded (1-3 minutes) by the appearance and/or gradual enhancement of the low-altitude AKR. This means that the explosive formation of the high-altitude electric field takes place in the course of the growing low-altitude acceleration. The development of the low-altitude acceleration region is thus a necessary condition for the ignition of the high-altitude bursty acceleration. The dH/dt component from a search-coil magnetometer at ground shows that a few minutes prior to substorm onsets, the quasi-DC component begins a negative excursion that is nearly synchronized with the start of the gradual enhancement of the low-altitude AKR, indicating a precursor-like behavior for the substorm. This negative variation of dH/dt suggests an exponentially increasing ionospheric current induced by the upward field-aligned current. At substorm onsets, the decrease in the quasi-DC variation of dH/dt further accelerates, indicating a sudden reinforcement of the field-aligned current.
Radial equilibrium of relativistic particle bunches in plasma wakefield accelerators
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.
Particle acceleration and non-thermal emission from galaxy clusters
Brunetti, G
2004-01-01
The existence and extent of non-thermal phenomena in galaxy clusters is now well established. A key question in our understanding of these phenomena is the origin of the relativistic electrons which may be constrained by the modelling of the fine radio properties of radio halos and of their statistics. In this paper we argue that present data favour a scenario in which the emitting electrons in the intracluster medium (ICM) are reaccelerated in situ on their way out. An overview of turbulent-particle acceleration models is given focussing on recent time-dependent calculations which include a full coupling between particles and MHD waves.
Observational Evidence of Particle Acceleration Associated with Plasmoid Motions
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...
Single particles accelerate final stages of capillary break up
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.
Connecting inflation with late cosmic acceleration by particle production
Nunes, Rafael C.
2016-04-01
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 nonrelativistic matter creation from the gravitational field acting on the quantum vacuum, which finally results in an effective equation of state (EoS) 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 (BAOs) and the cosmic microwave background (CMB).
Particle Acceleration on Megaparsec Scales in a Merging Galaxy Cluster
van Weeren, R J; Bruggen, M; Hoeft, M; 10.1126/science.1194293
2010-01-01
Galaxy clusters form through a sequence of mergers of smaller galaxy clusters and groups. Models of diffusive shock acceleration (DSA) suggest that in shocks that occur during cluster mergers, particles are accelerated to relativistic energies, similar to supernova remnants. Together with magnetic fields these particles emit synchrotron radiation and may form so-called radio relics. Here we report the detection of a radio relic for which we find highly aligned magnetic fields, a strong spectral index gradient, and a narrow relic width, giving a measure of the magnetic field in an unexplored site of the universe. Our observations prove that DSA also operates on scales much larger than in supernova remnants and that shocks in galaxy clusters are capable of producing extremely energetic cosmic rays.
Connecting inflation with late cosmic acceleration by particle production
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.
Stochastic Particle Acceleration in Turbulence Generated by the Magnetorotational Instability
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...
Reliability Approach for Machine Protection Design in Particle Accelerators
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.
Report on the 2005 Particle Accelerator Conference (PAC05)
International Nuclear Information System (INIS)
The 21st Particle Accelerator Conference, PAC05, took place at the Knoxville Convention Center (KCC) from Monday through Friday, May 16-20, 2005. Sponsored by the American Physical Society (APS), the Institute of Electrics and Electronics Engineers (IEEE) with its subdivision of Nuclear and Plasma Sciences Society (NPSS), the conference was hosted by the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source (SNS) Project and Thomas Jefferson National Accelerator Facility (JLab). The conference was chaired by Norbert Holtkamp, and the Local Organizing Committee was made up of staff from the ORNL SNS Project under the chairmanship of Stuart Henderson. The conference welcomed over 1400 delegates from the United States, Europe, Asia, the Middle East, South America and from as far away as Australia. Almost 1400 papers where processed during the conference and will be published on the Joint Accelerator Conferences Website (JACoW) page
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...
Functionally charged nanosize particles differentially activate BV2 microglia.
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...
Thermodynamic model for bouncing charged particles inside a capacitor
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.
Measurements of charged-particle distributions with the ATLAS detector
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.
Study of the liquid water luminescence induced by charged particles
International Nuclear Information System (INIS)
Many observations suggested that liquid water (with impurities) could give a luminescence output when irradiated with charged particles. We investigate theoretical and practical possibility of detecting such luminescence. Preliminary results on this possibility are presented, and a layout of the device proposed for measuring luminescence is given. (authors)
Charged Particle Energization and Transport in the Magnetotail during Substorms
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
Black Holes are neither Particle Accelerators nor Dark Matter Probes
McWilliams, Sean T.
2012-01-01
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,...
Simulations in the field of power converters for particle accelerators
Ngada, Narcisse
2016-01-01
The complexity and cost of building and running high-power electrical systems make the use of simulations unavoidable. The simulations available today provide great understanding about how systems really operate. This paper helps the reader to gain an insight into simulation in the field of power converters for particle accelerators. Starting with the definition and basic principles of simulation, two simulation types, as well as their leading tools, are presented: analog and numerical simula...
Search for new charged massive stable particles at CDF
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.
Guiding of charged particles through capillaries in insulating materials
Stolterfoht, Nikolaus; Yamazaki, Yasunori
2016-04-01
Studies of charged particle guiding through capillaries in insulating materials, performed during the last decade, are reviewed in a comprehensive manner. First, the principles of capillary guiding of slow highly charged ions are introduced describing the self-organized formation of charge patches. Basic quantities are defined, such as the guiding power characterizing a capillary. Challenges of the guiding experiments are pointed out. Then, experiments are described with emphasis on the guiding of highly charged ions in the keV energy range. Samples with an array of nanocapillaries as well as single macrocapillaries are treated. Emission profiles of transmitted ions are analyzed to establish scaling laws for the guiding angle, which quantifies the guiding power. Oscillations of the mean ion emission angle reveal the temporal dynamics of the charge patch formation. Next, experiments with ions of high (MeV) energies are focused on single tapered capillaries allowing for the production of a microbeam for various applications. Experiments concerning electrons are presented showing that apart from being elastically scattered these negative particles may enter into the capillary surface where they suffer energy losses. Finally, theoretical concepts of the capillary guiding are discussed. Simulations based on different charge transport methods clearly support the understanding of the guiding mechanisms. Altogether, capillary guiding involves several novel phenomena for which understanding have progressed far beyond their infancy.
Planetary spin period acceleration of particles in the Jovian magnetosphere
Energy Technology Data Exchange (ETDEWEB)
Carbary, J.F.; Hill, T.W.; Dessler, A.J.
1976-10-01
We describe a model for the acceleration of energetic protons and relativistic electrons in the Jovian magnetosphere, employing a four-step process in which ionospheric particles are (1) accelerated outward along field lines by the centrifugal force of corotation, (2) energized by magnetic field annihilation in the Jovian magnetospheric tail, (3) convected inward from the tail, thus experiencing adiabatic compression, and (4) diffused radially inward to form the Jovian trapped radiation belt. Steps 2--4 are analogous to the processes in the earth's magnetosphere that are thought to be responsible for the terrestrial radiation belts. There are three essential differences: the primary source of particles is assumed to be the ionosphere rather than the solar wind; steps 2 and 3 are not continuous but occur with the 10-hour period of Jupiter's rotation; and the energy source for the acceleration is the rotational energy of the planet rather than the solar wind. The periodicity is caused by a diurnal variation of the nightside distance to the last closed field line. The proposed model accounts for the 10-hour modulations in the energetic particle flux observed both outside and inside the Jovian magnetosphere by Pioneer 10 and Pioneer 11. We find that an additional mechanism is required in order to transfer some of the proton energy to the electrons (possibly through a wave instability of the two-stream type). Such an energy transfer mechanism appears also to be required in the terrestrial plasma sheet. (AIP)
Planetary spin period acceleration of particles in the Jovian magnetosphere
Carbary, J. F.; Dessler, A. J.; Hill, T. W.
1976-01-01
A four-step mechanism is proposed for the acceleration of energetic protons and relativistic electrons in Jupiter's magnetosphere. According to this mechanism, photoelectrons and ions from the Jovian ionosphere are: (1) ejected along magnetic-field lines toward the equator by the centrifugal force of corotation; (2) accelerated by magnetic-field annihiliation in the magnetotail, which process is modulated at Jupiter's rotational frequency; (3) trapped on closed field lines in the reconnection process, convected inward toward Jupiter from the merging region, and subjected to adiabatic compression; and (4) diffused inward by the conventional radial-diffusion process through a violation of the third adiabatic invariant. It is shown that the proposed mechanism produces magnetic moments much larger than those available from inward diffusion of solar-wind particles or motional emf acceleration at the Galilean satellites, provides a natural explanation for the 10-hr periodicity of the energetic particle fluxes observed inside the magnetosphere by the Pioneer spacecraft, and also produces a 10-hr periodicity in the energetic particle flux from the magnetosphere into interplanetary space in such a way that the phase of interplanetary flux variations is locked to the rotational phase of Jupiter
Particle acceleration and radiation in Pulsar Wind Nebulae
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...
Cosmic-Ray Generated Charged Particles for Nuclear Inspection
International Nuclear Information System (INIS)
Charged particles continuously rain down on the surface of the Earth. These charged particles primarily consist of muons and electrons. Muons are subatomic particles with the same charge as the electron, but with 200 times the mass. These particles are generated from interactions of primary cosmic-rays, primarily protons, with the upper atmosphere. Decision Sciences has implemented a tracking detector to measure the interactions of these particles with materials through which they pass: multiple Coulomb scattering and ionization energy loss and from these measurements is able to reconstruct a three-dimensional map of the density and atomic number of the materials in a scan volume. This map, combined with sensitive gamma detection capability of the tracking detector, enables the detection of nuclear and radiological materials that may be concealed in shielding, as well as discrimination of naturally occurring radioactive materials (NORM) from point sources that would be more associated with threats. Times to clear most non-threat cargo range from 30-60 seconds, with suspicious (heavy shielding or gamma emitting) scenes being held longer to confirm the presence of and identify nuclear or radiological materials. Extended scanning in this circumstance would typically take two to ten minutes. (author)
Monitoring of Hadrontherapy Treatments by Means of Charged Particle Detection
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
Monitoring of Hadrontherapy Treatments by Means of Charged Particle Detection.
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
Monitoring of Hadrontherapy Treatments by Means of Charged Particle Detection
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.
Charged Q-balls and boson stars and dynamics of charged test particles
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...
Brownian Dynamics of charged particles in a constant magnetic field
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.
Effects of dispersive wave modes on charged particles transport
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.
Technical training: AXEL-2011 - Introduction to Particle Accelerators
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:...
AXEL-2015 - Introduction To Particle Accelerators | starting 19 January
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 ...
Half a century of particle accelerators - 1950-2000
International Nuclear Information System (INIS)
In a lively historical account the author tells of the extraordinary progress made in accelerator physics since World War II. He focuses mainly on the history of French accelerators which evolved from small electrostatic accelerators purchased abroad to complex and powerful storage rings and colliders built by French engineers and physicists. He shows how these machines served not only particle physicists, but also researchers working with synchrotron light. He recalls how these two scientific communities with such different backgrounds learned how to work together. The author was an accelerator physicist, and a project leader who played a key role in storage ring R and D, as well as in accelerator construction and operation. He describes the international context of the period, and relates the discussions on scientific policy issues of the time. He tells us about the technical challenges to be overcome and discusses the question of maintaining the balance between national development and international involvement. A number of important yet unknown features of this scientific adventure are related. This short history also includes his thoughts about the gestation of large scientific instruments which, no doubt, will interest researchers involved in 'big science'
Technical training: AXEL-2006 - Introduction to Particle Accelerators
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...
Technical training: AXEL-2009 - Introduction to Particle Accelerators
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...
Technical training: AXEL-2010 - Introduction to particle accelerators
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...
Technical training: AXEL-2009 - Introduction to Particle Accelerators
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...
Technical Training: AXEL-2005: Introduction to Particle Accelerators
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...
Technical Training: AXEL-2005 - Introduction to Particle Accelerators
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...
Energy Technology Data Exchange (ETDEWEB)
Verkhoglyadova, Olga P. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL35899 (United States); Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA91109 (United States); Zank, Gary P.; Li, Gang [Department of Space Science, UAH, Huntsville, AL35899 (United States); Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL35899 (United States)
2015-02-12
Understanding the physics of Solar Energetic Particle (SEP) events is of importance to the general question of particle energization throughout the cosmos as well as playing a role in the technologically critical impact of space weather on society. The largest, and often most damaging, events are the so-called gradual SEP events, generally associated with shock waves driven by coronal mass ejections (CMEs). We review the current state of knowledge about particle acceleration at evolving interplanetary shocks with application to SEP events that occur in the inner heliosphere. Starting with a brief outline of recent theoretical progress in the field, we focus on current observational evidence that challenges conventional models of SEP events, including complex particle energy spectra, the blurring of the distinction between gradual and impulsive events, and the difference inherent in particle acceleration at quasi-parallel and quasi-perpendicular shocks. We also review the important problem of the seed particle population and its injection into particle acceleration at a shock. We begin by discussing the properties and characteristics of non-relativistic interplanetary shocks, from their formation close to the Sun to subsequent evolution through the inner heliosphere. The association of gradual SEP events with shocks is discussed. Several approaches to the energization of particles have been proposed, including shock drift acceleration, diffusive shock acceleration (DSA), acceleration by large-scale compression regions, acceleration by random velocity fluctuations (sometimes known as the “pump mechanism”), and others. We review these various mechanisms briefly and focus on the DSA mechanism. Much of our emphasis will be on our current understanding of the parallel and perpendicular diffusion coefficients for energetic particles and models of plasma turbulence in the vicinity of the shock. Because of its importance both to the DSA mechanism itself and to the
The relativistic solar particle event of 2005 January 20: origin of delayed particle acceleration
Klein, K.-L.; Masson, S.; 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 information on the location and nature of the acceleration region(s) by comparing the timing of relativistic protons detected on Earth and radiative signatures in the solar atmosphere during the particularly well-observed 2005 Jan. 20 event. This investigati...
Effect of Charge, Size and Temperature on Stability of Charged Colloidal Nano Particles
Institute of Scientific and Technical Information of China (English)
A. Golchoobi; A. Khosravi; H. Modarress; A Ahmadzadeh
2012-01-01
Molecular simulation of charged colloidal suspension is performed in NVT canonical ensemble using Monte Carlo method and primitive model.The well-known Derjaguin-Landau-Verwey-Overbeek theory is applied to account for effective interactions between particles.Effect of temperature,valance of micro-ions and the size of colloidal particles on the phase stability of the solution is investigated.The results indicate that the suspension is more stable at higher temperatures.On the other hand,for a more stable suspension to exist,lower microion valance is favorable.For micro-ions of higher charge the number of aggregates and the number of particle in each of aggregate on average is higher.However for the best of our results larger colloidal particle are less stable.Comparing the results with theoretical formula considering the influence of surface curvature shows qualitative consistency.
Improved techniques of impedance calculation and localization in particle accelerators
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 ...
Hawking radiation of scalars from charged accelerating and rotating black holes with NUT parameter
Jan, Khush
2013-01-01
We study the quantum tunneling of scalars from charged accelerating and rotating black hole with NUT parameter. For this purpose we use the charged Klein-Gordon equation. We apply WKB approximation and the Hamilton-Jacobi method to solve charged the Klein-Gordon equation. We find the tunneling probability of outgoing charged scalars from the event horizon of this black hole, and hence the Hawking temperature for this black hole.
Diagnostic and Detectors for Charging and Damage of Dielectrics in High-gradient Accelerators
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...
Accelerated simulation of stochastic particle removal processes in particle-resolved aerosol models
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.
Radiative Effect on Particle Acceleration via Relativistic Electromagnetic Expansion
Noguchi, K
2005-01-01
The radiation damping effect on the diamagnetic relativistic pulse accelerator (DRPA) is studied in two-and-half dimensional Particle-in-Cell (PIC) simulation with magnetized electron-positron plasmas. Self-consistently solved radiation damping force converts particle energy to radiation energy. The DRPA is still robust with radiation, and the Lorentz factor of the most high energy particles reach more than two thousand before they decouple from the electromagnetic pulse. Resulted emitted power from the pulse front is lower in the radiative case than the estimation from the non-radiative case due to the radiation damping. The emitted radiation is strongly linearly polarized and peaked within few degrees from the direction of Poynting flux.
Public Lecture | Philipe Lebrun | "Particle accelerators" | 2 September
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 ...
Isospin Effect of Charged Particle Multiplicity in Intermediate Energy Heavy Ion Collisions
Institute of Scientific and Technical Information of China (English)
HuRongjiang; WuHeyu; JinGenming; ZhuYongtai; DuanLimin; XiaoZhigang; WangHongwei
2003-01-01
The dependences of He and intermediate mass fragments (IMF) production rates in the reactions 55 MeV/u 40Ar+58,64 Ni on the isospin, impact parameter and primary excitation energy of the reaction nuclear system were studied by using the 4π charged particle multi-detector array system (MUDAL). For the mentioned two reaction systems, the measured He particle contribution in the total charged particle multiplicity increases with increasing the total charged particle multiplicity but for the contribution of IMFs in the total charged particle multiplicity increases with increasing the total charged particle multiplicity at lower total charged particle multiplicities, and latter on it drops down with further increasing of the total charged particle multiplicities (see Fig.l). The experimental results of these two reaction systems with the same nuclear charge indicate that the contribution of He and IMFs in the total charged particle multiplicities are obviously isospin dependent.
Particle acceleration and plasma energization in substorms: MHD and test particle studies
Energy Technology Data Exchange (ETDEWEB)
Birn, Joachim [Los Alamos National Laboratory
2015-07-16
The author organizes his slide presentation under the following topics: background, MHD simulation, orbit integration, typical orbits, spatial and temporal features, acceleration mechanisms, source locations, and source energies. Field-aligned energetic particle fluxes are shown for 45-keV electrons and 80-keV protons. It is concluded that the onset from local thin current sheet is electron tearing. Acceleration is mainly from field collapse, governed by E_{y} = -v_{x}XB_{z}: importance of localization; betatron acceleration (similar if nonadiabatic); 1st order Fermi, type B (or A; current sheet acceleration). There are two source regions (of comparable importance in magnetotail): - flanks, inner tail - drift entry - early, higher energy - outer plasma sheet - reconnection entry - later, lower energy. Both thermal and suprathermal sources are important, with limited energy range for acceleration
A new laser test stand for simulating charged-particle tracks
Unno, Y.; Iwata, Y.; Ohsugi, T.; Kohriki, T.; Kondo, T.; Terada, S.; Iwasaki, H.; Yamada, Y.
1996-02-01
We report on the construction of a new laser test stand equipped with a 1064 nm pulsed infrared YAG laser for simulating the passage of a charged particle in a silicon detector. The standard semiconductor repairing tool, the so-called laser-cutter, has been modified to have a newly developed optics which has the ability to reduce the light by the order of 10 6-10 8 and to adjust the spot size to several microns. As an application we measured the position dependence of the induced signals in a silicon-strip detector when the laser light hits in the region between the strips. The measurement has show that this device is very effective in evaluating the detailed response of a silicon detector without using charged particles generated by accelerators.
Self-modulation of a relativistic charged-particle beam as thermal matter wave envelope
International Nuclear Information System (INIS)
The self-modulation, resulting from its interaction with the surrounding medium, of a relativistic charged-particle beam traveling through an overdense plasma, is investigated theoretically. The description of the transverse nonlinear and collective beam dynamics of an electron (or positron) beam in a plasma-based accelerator is provided in terms of a thermal matter wave envelope propagation. This is done using the quantum-like description provided by the thermal wave model. It is shown that the charged-particle beam dynamics is governed by a Zakharov-type system of equations, comprising a nonlinear Schrödinger equation that is governing the spatiotemporal evolution of the thermal matter wave envelope and a Poisson-like equation for the wake potential that is generated by the bunch itself
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...
On the compressibility effect in test particle acceleration by magnetohydrodynamic turbulence
González, C A; Mininni, P D; Matthaeus, W H
2016-01-01
The effect of compressibility in charged particle energization by magnetohydrodynamic (MHD) fields is studied in the context of test particle simulations. This problem is relevant to the solar wind and the solar corona due to the compressible nature of the flow in those astrophysical scenarios. We consider turbulent electromagnetic fields obtained from direct numerical simulations of the MHD equations with a strong background magnetic field. In order to explore the compressibilty effect over the particle dynamics we performed different numerical experiments: an incompressible case, and two weak compressible cases with Mach number M = 0.1 and M = 0.25. We analyze the behavior of protons and electrons in those turbulent fields, which are well known to form aligned current sheets in the direction of the guide magnetic field. We show that compressibility enhances the efficiency of proton acceleration, and that the energization is caused by perpendicular electric fields generated between currents sheets. On the ot...
P.I.A.F.E. project: production of highly charged particles for radioactive ion beams
International Nuclear Information System (INIS)
The transformation of a mono-charged ion beam into a multicharged ion beam is an important problem in the projects of radioactive beams acceleration. This transformation must be performed with the best possible efficiency and in the shortest possible time to avoid the loss of particles by radioactive degenerescence. A ionization method using an electron cyclotron resonance (ECR) source is proposed. It consists in the fast capture by the ECR plasma of the radioactive elements injected inside this source in the form of a mono-charged ion beam. This method gives good results (2 to 6% efficiency to move from the 1+ to the 9+ charge state) for the ionization of alkaline elements, rare and metallic gases, with fast times of response allowing the ionization of radioactive products with a lifetime inferior to 1 s. (J.S.)
Energy Technology Data Exchange (ETDEWEB)
BEEBE - WANG,J.; LUCCIO,A.U.; D IMPERIO,N.; MACHIDA,S.
2002-06-03
Space charge in high intensity beams is an important issue in accelerator physics. Due to the complicity of the problems, the most effective way of investigating its effect is by computer simulations. In the resent years, many space charge simulation methods have been developed and incorporated in various 2D or 3D multi-particle-tracking codes. It has becoming necessary to benchmark these methods against each other, and against experimental results. As a part of global effort, we present our initial comparison of the space charge methods incorporated in simulation codes ORBIT++, ORBIT and SIMPSONS. In this paper, the methods included in these codes are overviewed. The simulation results are presented and compared. Finally, from this study, the advantages and disadvantages of each method are discussed.
Particle acceleration inside PWN: Simulation and observational constraints with INTEGRAL
International Nuclear Information System (INIS)
The context of this thesis is to gain new constraints on the different particle accelerators that occur in the complex environment of neutron stars: in the pulsar magnetosphere, in the striped wind or wave outside the light cylinder, in the jets and equatorial wind, and at the wind terminal shock. An important tool to constrain both the magnetic field and primary particle energies is to image the synchrotron ageing of the population, but it requires a careful modelling of the magnetic field evolution in the wind flow. The current models and understanding of these different accelerators, the acceleration processes and open questions have been reviewed in the first part of the thesis. The instrumental part of this work involves the IBIS imager, on board the INTEGRAL satellite, that provides images with 12' resolution from 17 keV to MeV where the SPI spectrometer takes over up, to 10 MeV, but with a reduced 2 degrees resolution. A new method for using the double-layer IBIS imager as a Compton telescope with coded mask aperture. Its performance has been measured. The Compton scattering information and the achieved sensitivity also open a new window for polarimetry in gamma rays. A method has been developed to extract the linear polarization properties and to check the instrument response for fake polarimetric signals in the various backgrounds and projection effects
Acceleration of low-energy protons and alpha particles at interplanetary shock waves
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.
Solar Energetic Particle drifts and the energy dependence of 1 AU charge states
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...
Detection of charged particles through a photodiode: design and analysis
International Nuclear Information System (INIS)
This project develops and construct an charge particle detector mean a pin photodiode array, design and analysis using a silicon pin Fotodiodo that generally is used to detect visible light, its good efficiency, size compact and reduced cost specifically allows to its use in the radiation monitoring and alpha particle detection. Here, so much, appears the design of the system of detection like its characterization for alpha particles where one is reported as alpha energy resolution and detection efficiency. The equipment used in the development of work consists of alpha particle a triple source composed of Am-241, Pu-239 and Cm-244 with 5,55 KBq as total activity, Maestro 32 software made by ORTEC, a multi-channel card Triumph from ORTEC and one low activity electroplated uranium sample. (Author)
Technical training: AXEL-2008 - Introduction to Particle Accelerators
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...
Charge collection studies in irradiated HV-CMOS particle detectors
Affolder, A.; Andelković, M.; Arndt, K.; Bates, R.; Blue, A.; Bortoletto, D.; Buttar, C.; Caragiulo, P.; Cindro, V.; Das, D.; Dopke, J.; Dragone, A.; Ehrler, F.; Fadeyev, V.; Galloway, Z.; Gorišek, A.; Grabas, H.; Gregor, I. M.; Grenier, P.; Grillo, A.; Hommels, L. B. A.; Huffman, T.; John, J.; Kanisauskas, K.; Kenney, C.; Kramberger, G.; Liang, Z.; Mandić, I.; Maneuski, D.; McMahon, S.; Mikuž, M.; Muenstermann, D.; Nickerson, R.; Perić, I.; Phillips, P.; Plackett, R.; Rubbo, F.; Segal, J.; Seiden, A.; Shipsey, I.; Song, W.; Stanitzki, M.; Su, D.; Tamma, C.; Turchetta, R.; Vigani, L.; Volk, J.; Wang, R.; Warren, M.; Wilson, F.; Worm, S.; Xiu, Q.; Zavrtanik, M.; Zhang, J.; Zhu, H.
2016-04-01
Charge collection properties of particle detectors made in HV-CMOS technology were investigated before and after irradiation with reactor neutrons. Two different sensor types were designed and processed in 180 and 350 nm technology by AMS. Edge-TCT and charge collection measurements with electrons from 90Sr source were employed. Diffusion of generated carriers from undepleted substrate contributes significantly to the charge collection before irradiation, while after irradiation the drift contribution prevails as shown by charge measurements at different shaping times. The depleted region at a given bias voltage was found to grow with irradiation in the fluence range of interest for strip detectors at the HL-LHC. This leads to large gains in the measured charge with respect to the one before irradiation. The increase of the depleted region was attributed to removal of effective acceptors. The evolution of depleted region with fluence was investigated and modeled. Initial studies show a small effect of short term annealing on charge collection.
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.
Low energy charged particles interacting with amorphous solid water layers
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.
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.
Does the electromagnetic field of an accelerated charge satisfy Maxwell equations?
Chubykalo, A E; Chubykalo, Andrew E.; Vlaev, Stoyan J.
1997-01-01
We considered the electromagnetic field of a charge moving with a constant acceleration along an axis. We found that this field obtained from the Lienard-Wiechert potentials does not satisfy Maxwell equations.
Nuclear Deexcitation Gamma Ray Lines from Accelerated Particle Interactions
Murphy, R. J.; Kozlovsky, B.; Ramaty, R.
2001-12-01
Since the comprehensive treatment of nuclear deexcitation gamma-ray line emission by Ramaty, Kozlovsky and Lingenfelter in 1979, many new laboratory measurements of the cross sections have become available. Such new measurements allow improved theoretical evaluations of cross sections and the addition of more lines in the analyses of gamma-ray data. For example, the inclusion of lines produced by energetic 3He will provide unique information about its abundance. We present these improved cross sections as a function of the projectile energy for proton, alpha and 3He reactions with He, C, N, O, Ne, Mg, Al, Si, S, Ca and Fe. We also present calculations of gamma-ray line yields based on these cross sections and show how line ratios depend on the assumed ambient and accelerated-particle abundances and on the accelerated-particle energy spectrum. Such calculations are essential for interpretation of gamma-ray line observations of astrophysical sites that contain significant fluxes of energetic particles such as solar flares, the Earth's atmosphere, planetary atmospheres and surfaces, the interstellar medium and galactic nebulae. Part of the research reported here was supported by NASA DPR S92680F and W19977.
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.
Cataract production in mice by heavy charged particles
International Nuclear Information System (INIS)
The cataractogenic effects of heavy charged particles have been evaluated in mice in relation to dose and ionization density (LET/sub infinity/). The study was undertaken due to the high potential for eye exposures to HZE particles among SPS personnel working in outer space. This has made it imperative that the relative biological effectiveness (RBE) in relation to LET/sub infinity/ for various particles be defined so that appropriate quality factors (Q) could be assigned for estimation of risk. Although mice and men differ in susceptibility to radiation-induced cataracts, the results from this project should assist in defining appropriate quality factors in relation to LET/sub infinity/, particle mass, charge, or velocity. Evaluation of results indicated that : (1) low single doses (5 to 20 rad) of iron (56Fe) or argon (40Ar) particles are cataractogenic at 11 to 18 months after irradiation; (2) onset and density of the opacification are dose related; (3) cataract density (grade) at 9, 11, 13, and 16 months after irradiation shows partial LET/sub infinity/-dependence; and (4) the severity of cataracts is reduced significantly when 417 rad of 60Co gamma radiation is given in 24 weekly 17 rad fractions compared to giving this radiation as a single dose, but cataract severity is not reduced by fractionation of 12C doses over 24 weeks
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.
Laser-driven particle acceleration towards radiobiology and medicine
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.
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.
Proceedings of the 22nd Particle Accelerator Conference (PAC'07)
International Nuclear Information System (INIS)
The twenty-second Particle Accelerator Conference, PAC'07, took place at the Albuquerque Convention Centre in Albuquerque, the largest city in New Mexico, from Monday to Friday, 2007 June 25 to 29. It was attended by over 1350 delegates from 25 different countries (63% North America, 24% Europe, 11% Asia and 2% Other), and was held under the auspices of the two professional societies that oversee and make holding this series of conferences possible, the Division of Physics of Beams within APS, and the Nuclear and Plasma Sciences Society within IEEE. As host of the conference, Los Alamos National Laboratory (LANL) is especially thanked for their many contributions and assistance both prior to and during the conference. The Convention Center was an ideal location for information sharing and discussions between the interdisciplinary aspects of the accelerator community, as well as for related meetings and ad-hoc 'rump' sessions.
The Motion of a Pair of Charged Particles
Franklin, J
2013-01-01
We re-visit the problem of two (oppositely) charged particles interacting electromagnetically in one dimension with retarded potentials and no radiation reaction. The specific quantitative result of interest is the time it takes for the particles to fall in towards one another. Starting with the non-relativistic form, we answer this question while adding layers of complexity until we arrive at the full relativistic delay differential equation that governs this problem. That case can be solved using the Synge method, which we describe and discuss.
Space-charge effects in ultra-high current electron bunches generated by laser-plasma accelerators
Energy Technology Data Exchange (ETDEWEB)
Grinner, F. J.; Schroeder, C. B.; Maier, A. R.; Becker, S.; Mikhailova, J. M.
2009-02-11
Recent advances in laser-plasma accelerators, including the generation of GeV-scale electron bunches, enable applications such as driving a compact free-electron-laser (FEL). Significant reduction in size of the FEL is facilitated by the expected ultra-high peak beam currents (10-100 kA) generated in laser-plasma accelerators. At low electron energies such peak currents are expected to cause space-charge effects such as bunch expansion and induced energy variations along the bunch, potentially hindering the FEL process. In this paper we discuss a self-consistent approach to modeling space-charge effects for the regime of laser-plasma-accelerated ultra-compact electron bunches at low or moderate energies. Analytical treatments are considered as well as point-to-point particle simulations, including the beam transport from the laser-plasma accelerator through focusing devices and the undulator. In contradiction to non-self-consistent analyses (i.e., neglecting bunch evolution), which predict a linearly growing energy chirp, we have found the energy chirp reaches a maximum and decreases thereafter. The impact of the space-charge induced chirp on FEL performance is discussed and possible solutions are presented.
The Search for Fractional Charge Elementary Particles and Very Massive Particles in Bulk Matter
Perl, Martin Lewis; Kim, P C; Lee, E R; Lee, I T; Loomba, D; Perl, Martin L.; Halyo, Valerie; Kim, Peter C.; Lee, Eric R.; Lee, Irwin T.; Loomba, Dinesh
2000-01-01
We describe our ongoing work on, and future plans for, searches in bulk matter for fractional charge elementary particles and very massive elementary particles. Our primary interest is in searching for such particles that may have been produced in the early universe and may be found in the more primeval matter available in the solar system: meteorites, material from the moon's surface, and certain types of ancient terrestrial rocks. In the future we are interested in examining material brought back by sample return probes from asteroids. We will describe our experimental methods that are based on new modifications of the Millikan liquid drop technique and modern technology: micromachining, CCD cameras, and desktop computers. Extensions of our experimental methods and technology allow searches for very massive charged particles in primeval matter; particles with masses greater than 10**13 GeV. In the first such searches carried out on earth there will be uncertainties in the mass search range. Therefore we wil...
Effects of solids with charged particles fluxes. Modern status of simulation investigation
International Nuclear Information System (INIS)
The data are presented on investigations carried out in Kharkov Institute of Physics and Technology (KIPT) during last years in the field of simulation and studies of radiation damage in materials with the use of accelerators of charged particles. Using irradiation with charged particle beams one could reproduce and examine practically all the known radiation effects and investigate physical nature of these effects in more details under well-controlled conditions. Simulation experiments together with results of reactor investigation contribute much to radiation physics phenomena, radiation and ion-beam technologies as well as to creation of low-activated materials with good radiation resistance. The advantages and disadvantages of simulation experiments in comparison with reactor tests are discussed. The using of new types of accelerators (of two and three beams) and of modern methods of research allows minimize the restrictions and disadvantages in the using of results of simulation experiments caused by low depth of damaged layer. Modern status of using accelerators demand by such main tasks: understanding of radiation damage mechanism of nuclear materials; achievement of better knowledge of the nature of point defects and interaction between them; set up the correlation between radiation-induced defects, structure phase evolution and material degradation mechanism; investigation of stability of systems which have nanoscale features. It is especially important for development and prediction of radiation behavior at high irradiation doses of nano-precipitates in ODS steels, which are the most pronounce materials for of next generation. (authors)
Interdefect charge exchange in silicon particle detectors at cryogenic temperatures
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...
Charged-Particle Multiplicity in Proton-Proton Collisions
Grosse-Oetringhaus, Jan Fiete; Reygers, Klaus
2009-01-01
This article summarizes and critically reviews measurements of charged-particle multiplicity distributions and pseudorapidity densities in p+p(pbar) collisions between sqrt(s) = 23.6 GeV and sqrt(s) = 1.8 TeV. Related theoretical concepts are briefly introduced. Moments of multiplicity distributions are presented as a function of sqrt(s). Feynman scaling, KNO scaling, as well as the description of multiplicity distributions with a single negative binomial distribution and with combinations of...
Optimizing interactive program for charged particle transport system design
International Nuclear Information System (INIS)
A computer program for charged particle transport system design is described. The program is written in the BASIC language and allows one to make calculations in dialogue with the computer. The BASTRA program permits to get output information both in digital and in graphical forms. The method for optimization is described, that allows one to put 10 limitation on beam parameters in arbitrary places of the transport system. The program can be adapted on every computer having the BASIC language in its software
The spectrum of particles accelerated in relativistic, collisionless shocks
Keshet, Uri; Waxman, Eli
2004-01-01
We analytically study diffusive particle acceleration in relativistic, collisionless shocks. We find a simple relation between the spectral index s and the anisotropy of the momentum distribution along the shock front. Based on this relation, we obtain s = (3beta_u - 2beta_u*beta_d^2 + beta_d^3) / (beta_u - beta_d) for isotropic diffusion, where beta_u (beta_d) is the upstream (downstream) fluid velocity normalized to the speed of light. This result is in agreement with previous numerical det...
Laser-Accelerated Proton Beams as a New Particle Source
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...
New modes of particle accelerations techniques and sources. Formal report
International Nuclear Information System (INIS)
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
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.
Microsparks Generated by Charged Particles in Dielectric Liquids
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 type of discharge can provide a simple means of generating non-thermal plasmas in dielectric liquids, such as oils or other hydrocarbons, which can be used to chemically process the liquids. Such a technology may lead to a highly efficient method of heavy oil upgrading which can be easily scaled. In order to understand the plasma properties optical emission spectroscopy is carried out for various hydrocarbons and voltage-current characteristics are used to determine the energy cost for this process. [4pt] [1] Melcher, James R. Continuum Electromechanics. Cambridge, MA: MIT Press, 1981.[0pt] [2] Jones, Thomas B. Electromechanics of Particles. Cambridge University Press 1995.[0pt] [3] Staack, D., Fridman, A., Gutsol, A., Gogotsi, Y. and Friedman, G. 2008, Angew. Chem., Int. Ed. 47, 8020.
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.)
Black holes are neither particle accelerators nor dark matter probes.
McWilliams, Sean T
2013-01-01
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.
Beam optics and lattice design for particle accelerators
Holzer, Bernhard J
2013-01-01
The goal of this manuscript is to give an introduction into the design of the magnet lattice and as a consequence into the transverse dynamics of the particles in a synchrotron or storage ring. Starting from the basic principles of how to design the geometry of the ring we will briefly review the transverse motion of the particles and apply this knowledge to study the layout and optimization of the principal elements, namely the lattice cells. The detailed arrangement of the accelerator magnets within the cells is explained and will be used to calculate well defined and predictable beam parameters. The more specific treatment of low beta insertions is included as well as the concept of dispersion suppressors that are an indispensable part of modern collider rings.
Propositions for a PDF model based on fluid particle acceleration
International Nuclear Information System (INIS)
This paper describes theoretical propositions to model the acceleration of a fluid particle in a turbulent flow. Such a model is useful for the PDF approach to turbulent reactive flows as well as for the Lagrangian modelling of two-phase flows. The model developed here draws from ideas already put forward by Sawford but which are generalized to the case of non-homogeneous flows. The model is built so as to revert continuously to Pope's model, which uses a Langevin equation for particle velocities, when the Reynolds number becomes very high. The derivation is based on the technique of fast variable elimination. This technique allow a careful analysis of the relations between different levels of modelling. It also allows to address certain problems in a more rigorous way. In particular, application of this technique shows that models presently used can in principle simulate bubbly flows including the pressure-gradient and added-mass forces. (author)
Black Holes are neither Particle Accelerators nor Dark Matter Probes
McWilliams, Sean T
2012-01-01
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...
Can cosmic acceleration be caused by exotic massless particles?
Stichel, P C
2009-01-01
To describe dark energy we introduce a fluid model with no free parameter on the microscopic level. The constituents of this fluid are massless particles which are a dynamical realisation of the unextended D = (3+1) Galilei algebra. These particles are exotic as they live in an enlarged phase space. Their only interaction is with gravity. A minimal coupling to the gravitational field, satisfying Einstein's equivalence principle, leads to a dynamically active gravitational mass density of either sign. A two-component model containing matter (baryonic and dark) and dark energy leads, through the cosmological principle, to Friedmann-like equations. Their solutions show a deceleration phase for the early universe and an acceleration phase for the late universe. We also discuss a reduced model (one component dark sector) and the inclusion of radiation. Our model shows no stationary modification of Newton's gravitational potential.
Combined gravitational and electromagnetic self-force on charged particles in electrovac spacetimes
Linz, Thomas M; Wiseman, Alan G
2014-01-01
We consider the self-force on a charged particle moving in a curved spacetime with a background electromagnetic field, extending previous studies to situations in which gravitational and electromagnetic perturbations are comparable. The formal expression $f^{ret}_\\alpha$ for the self-force on a particle, written in terms of the retarded perturbed fields, is divergent, and a renormalization is needed to find the particle's acceleration at linear order in its mass $m$ and charge $e$. We assume that, as in previous work in a Lorenz gauge, the renormalization for accelerated motion comprises an angle average and mass renormalization. Using the short distance expansion of the perturbed electromagnetic and gravitational fields, we show that the renormalization is equivalent to that obtained from a mode sum regularization in which one subtracts from the expression for the self-force in terms of the retarded fields a singular part field comprising only the leading and subleading terms in the mode sum. The most striki...
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...
Short term course on Particle Accelerator Facilities in BARC: lecture notes
International Nuclear Information System (INIS)
This course will focus on the working principles of different types of accelerators and the safety and regulatory aspects of the particle accelerators in BARC. We sincerely hope that the course will benefit all those involved in the design, operation, maintenance as well as regulation of the particle accelerators. The course will bring together all the stakeholders on a common platform to understand and communicate various aspects of particle accelerators. Papers relevant to INIS are indexed separately
Acceleration of particles in Janis-Newman-Winicour singularities
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,...
Particle acceleration and transport in the solar atmosphere
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.
Cataract production in mice by heavy charged particles
Ainsworth, E. J.; Jose, U.; Yang, V. V.; Barker, M. E.
1981-01-01
The cataractogenic effects of heavy charged particles are evaluated in mice in relation to dose and ionization density. The relative biological effectiveness in relation to linear energy transfer for various particles is considered. Results indicated that low single doses (5 to 20 rad) of Fe 56 or Ar 40 particles are cataractogenic at 11 to 18 months after irradiation; onset and density of the opacification are dose related and cataract density (grade) at 9, 11, 13, and 16 months after irradiation shows partial linear energy transfer dependence. The severity of cataracts is reduced significantly when 417 rad of Co 60 gamma radiation is given in 24 weekly 17 rad fractions compared to giving this radiation as a single dose, but cataract severity is not reduced by fractionation of C12 doses over 24 weeks.
Nonlinear δf Simulations of Collective Effects in Intense Charged Particle Beams
International Nuclear Information System (INIS)
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, et al., in Proc. of the Particle Accelerator Conference, Chicago, 2001 (IEEE, Piscataway, NJ, 2001), Vol. 1, p. 688.] at the Los Alamos National Laboratory agree well with experimental observations. Large-scale parallel simulations have also been carried out for the ion-electron two-stream instability in the very-high-intensity heavy ion beams envisioned for heavy ion fusion applications. In both cases, the simulation results indicate that the dominant two-stream instability has a dipole-mode (hose-like) structure and can be stabilized by a modest axial momentum spread of the beam particles
Particle acceleration in ultra-relativistic parallel shock waves
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...
Aging of organic materials around high-energy particle accelerators
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.
Particle Acceleration in Relativistic Electron-Ion Outlfows
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...
Particle Acceleration and Plasma Heating in the Chromosphere
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.
Search for doubly-charged negative ions via accelerator mass spectrometry
International Nuclear Information System (INIS)
The Argonne FN tandem accelerator in conjunction with an Enge split-pole magnetic spectrograph has been used as a highly sensitive mass spectrometer to search for doubly charged negative ions of 11B, 12C and 16O. No evidence for the formation of these ions in an inverted sputter source and the subsequent acceleration in the tandem has been found. The following limits for the ratio of doubly-charged to singly-charged ions were measured: X--/X- -15, 11B; -15, 12C; -14, 16O. A relatively abundant formation of the short lived, metastable He- ion in the sputter source has been observed
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...
Theory of intense beams of charged particles optics of charged particle analyzers
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
Hawking Radiation of Dirac Particles in an Arbitrarily Accelerating Kinnersley Black Hole
Wu, S Q
2002-01-01
Quantum thermal effect of Dirac particles in an arbitrarily accelerating Kinnersley black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the advanced time and the angles. The Hawking thermal radiation spectrum of Dirac particles contains a new term which represents the interaction between particles with spin and black holes with acceleration. This spin-acceleration coupling effect is absent from the thermal radiation spectrum of scalar particles.
The programme library for numerical simulation of charged particle dynamics in transportation lines
International Nuclear Information System (INIS)
The description of a PC codes library to simulate the beam transportation of charged particles is presented. The codes are realized on IBM PC in Visual Basic common interface. It is destined for the simulation and optimization of beam dynamics and based on the successive and consistent use of two methods: the momentum method of distribution functions (RMS technique) and the particle-particle method (PP-Method). The library allows to calculate the RMS parameters of electron and ion beams, passing through a set of quadrupoles, solenoids, bends, accelerating sections. The RMS code is a fast code very suitable for the first test, design and optimization of the beam line parameters. The PP code requires more time for execution but provides a high accuracy of simulation taking into account the space charge effects, aberrations and beam losses. One of the main advantages of PP code presented here is an ability to simulate a real multicomponent beam of different masses and charged states of ions from ion sources
Compact and energy saving magnet technology for particle accelerators
International Nuclear Information System (INIS)
Despite the fact that funding agencies and industrial users of particle accelerators get more and more alerted about costs of civil engineering, installation and operation, only little effort has been put into development of sustainable, energy and cost saving accelerator technology. In order to reduce the total-cost-of ownership of accelerator magnets, operating at high electrical power for twenty years or more, permanent magnet based Green Magnet technology has been developed at a consortium around Danfysik's R and D team. Together with our partners from ISA, Aarhus University, the Aarhus School of Engineering, the company Sintex and Aalborg University all obstacles in applying permanent magnet technology as e.g. thermal drift and inhomogeneities of magnetic fields have been overcome. The first Green Magnet has now been operated for more than half a year in an Accelerator Mass Spectrometry facility at the ETH in Zurich. The performance of this B=0.43T 90 deg. H-type bending magnet and the most recently builtB=1T, 30 deg. C-type Green Magnet for the synchrotron light source ASTRID2 at ISA in Aarhus will be presented. Danfysik also is designing, manufacturing and testing 60 compact magnet systems, developed at MAX-Lab for the new MAXIV 3.0 GeV synchrotron light source. In addition, 12 for the 1.5 GeV light source and another 12 for the new SOLARIS light source in Krakow, Poland are buying built. Up to a dozen or more magnet functions have been integrated into one yoke of these compact magnet systems, which makes the new MAXIV light sources compact, energy saving and at the same time very bright. Test results and design concepts of the new MAXIV and SOLARIS magnets will be presented. (author)
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.
Microscopic visualization of a biological response to charged particle traversal
Taucher-Scholz, G.; Jakob, B.; Becker, G.; Scholz, M.
2003-08-01
Understanding the molecular mechanisms underlying biological effects of charged particle radiation has become increasingly important in view of the use of ion beams in tumor therapy. Elucidating how the enhanced efficiency of densely ionizing radiation in cell killing is related to the initial causative lesions, namely DNA double-strand breaks, constitutes a major task in radiobiology. The inhomogeneous spatial distribution of energy deposition leading to the induction of more complex and less reparable DNA lesions is the basis for high-LET effects. But the cellular response to radiation damage also involves the interplay between repair and signal transduction proteins with the aim of coordinating the processing of DNA damage and cell cycle progression to allow time for repair. Charged particles are used as a probe for the production of localized subcellular damage to study these aspects of the biological response to ionizing radiation. Immunocytochemical techniques applied in combination with confocal laser microscopy allow to monitor the relocalization of DNA damage response proteins within individual nuclei following irradiation. In particular, the rapid accumulation of the signalling protein p21 at sites of heavy ion-induced DNA damage reflects the microscopic distribution of dose deposited within nuclei of irradiated human fibroblasts. The biological response pattern for p21 is presented for high and low energy ion beams, involving different particle species and representing a wide range of radiation qualities.