WorldWideScience

Sample records for states particle accelerator

  1. Modular compact solid-state modulators for particle accelerators

    Science.gov (United States)

    Zavadtsev, A. A.; Zavadtsev, D. A.; Churanov, D. V.

    2017-12-01

    The building of the radio frequency (RF) particle accelerator needs high-voltage pulsed modulator as a power supply for klystron or magnetron to feed the RF accelerating system. The development of a number of solid-state modulators for use in linear accelerators has allowed to develop a series of modular IGBT based compact solid-state modulators with different parameters. This series covers a wide range of needs in accelerator technology to feed a wide range of loads from the low power magnetrons to powerful klystrons. Each modulator of the series is built on base of a number of unified solid-state modules connected to the pulse transformer, and covers a wide range of modulators: voltage up to 250 kV, a peak current up to 250 A, average power up to 100 kW and the pulse duration up to 20 μsec. The parameters of the block with an overall dimensions 880×540×250 mm are: voltage 12 kV, peak current 1600 A, pulse duration 20 μsec, average power 10 kW with air-cooling and 40 kW with liquidcooling. These parameters do not represent a physical limit, and modulators to parameters outside these ranges can be created on request.

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

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, William A.; /MIT

    2008-09-01

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

  3. Particle diffusion and localized acceleration in inhomogeneous AGN jets - Part I: Steady-state spectra

    OpenAIRE

    Chen, Xuhui; Pohl, Martin; Boettcher, Markus

    2014-01-01

    We study the acceleration, transport, and emission of particles in relativistic jets. Localized stochastic particle acceleration, spatial diffusion, and synchrotron as well as synchrotron self-Compton emission are considered in a leptonic model. To account for inhomogeneity, we use a 2D axi-symmetric cylindrical geometry for both relativistic electrons and magnetic field. In this first phase of our work, we focus on steady-state spectra that develop from a time-dependent model. We demonstrate...

  4. Energy-Dependent Ionization States of Shock-Accelerated Particles in the Solar Corona

    Science.gov (United States)

    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.

  5. Piezoelectric particle accelerator

    Science.gov (United States)

    Kemp, Mark A.; Jongewaard, Erik N.; Haase, Andrew A.; Franzi, Matthew

    2017-08-29

    A particle accelerator is provided that includes a piezoelectric accelerator element, where the piezoelectric accelerator element includes a hollow cylindrical shape, and an input transducer, where the input transducer is disposed to provide an input signal to the piezoelectric accelerator element, where the input signal induces a mechanical excitation of the piezoelectric accelerator element, where the mechanical excitation is capable of generating a piezoelectric electric field proximal to an axis of the cylindrical shape, where the piezoelectric accelerator is configured to accelerate a charged particle longitudinally along the axis of the cylindrical shape according to the piezoelectric electric field.

  6. High Energy Particle Accelerators

    CERN Multimedia

    Audio Productions, Inc, New York

    1960-01-01

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

  7. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2007-01-01

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

  8. Amps particle accelerator definition study

    Science.gov (United States)

    Sellen, J. M., Jr.

    1975-01-01

    The Particle Accelerator System of the AMPS (Atmospheric, Magnetospheric, and Plasmas in Space) payload is a series of charged particle accelerators to be flown with the Space Transportation System Shuttle on Spacelab missions. In the configuration presented, the total particle accelerator system consists of an energetic electron beam, an energetic ion accelerator, and both low voltage and high voltage plasma acceleration devices. The Orbiter is illustrated with such a particle accelerator system.

  9. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2015-01-01

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

  10. HIGH ENERGY PARTICLE ACCELERATOR

    Science.gov (United States)

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

    1959-04-14

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

  11. Particle Accelerator Focus Automation

    Science.gov (United States)

    Lopes, José; Rocha, Jorge; Redondo, Luís; Cruz, João

    2017-08-01

    The Laboratório de Aceleradores e Tecnologias de Radiação (LATR) at the Campus Tecnológico e Nuclear, of Instituto Superior Técnico (IST) has a horizontal electrostatic particle accelerator based on the Van de Graaff machine which is used for research in the area of material characterization. This machine produces alfa (He+) and proton (H+) beams of some μA currents up to 2 MeV/q energies. Beam focusing is obtained using a cylindrical lens of the Einzel type, assembled near the high voltage terminal. This paper describes the developed system that automatically focuses the ion beam, using a personal computer running the LabVIEW software, a multifunction input/output board and signal conditioning circuits. The focusing procedure consists of a scanning method to find the lens bias voltage which maximizes the beam current measured on a beam stopper target, which is used as feedback for the scanning cycle. This system, as part of a wider start up and shut down automation system built for this particle accelerator, brings great advantages to the operation of the accelerator by turning it faster and easier to operate, requiring less human presence, and adding the possibility of total remote control in safe conditions.

  12. Particle Accelerator Focus Automation

    Directory of Open Access Journals (Sweden)

    Lopes José

    2017-08-01

    Full Text Available The Laboratório de Aceleradores e Tecnologias de Radiação (LATR at the Campus Tecnológico e Nuclear, of Instituto Superior Técnico (IST has a horizontal electrostatic particle accelerator based on the Van de Graaff machine which is used for research in the area of material characterization. This machine produces alfa (He+ and proton (H+ beams of some μA currents up to 2 MeV/q energies. Beam focusing is obtained using a cylindrical lens of the Einzel type, assembled near the high voltage terminal. This paper describes the developed system that automatically focuses the ion beam, using a personal computer running the LabVIEW software, a multifunction input/output board and signal conditioning circuits. The focusing procedure consists of a scanning method to find the lens bias voltage which maximizes the beam current measured on a beam stopper target, which is used as feedback for the scanning cycle. This system, as part of a wider start up and shut down automation system built for this particle accelerator, brings great advantages to the operation of the accelerator by turning it faster and easier to operate, requiring less human presence, and adding the possibility of total remote control in safe conditions.

  13. Particle Acceleration by MHD Turbulence

    OpenAIRE

    Cho, Jungyeon; Lazarian, A.

    2005-01-01

    Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for revisions in the picture of particle acceleration. We make use of the recently established scaling of slow and fast MHD modes in strong and weak MHD turbulence to provide a systematic study of particle acceleration in magnetic pressure (low-$\\beta$) and gaseous pressure (high-$\\beta$) dominated plasmas. We consider the acceleration by large scale compressions in both slow and fast particle diffusion limits. We c...

  14. Particle acceleration in binaries

    Directory of Open Access Journals (Sweden)

    Sinitsyna V.G.

    2017-01-01

    Full Text Available Cygnus X-3 massive binary system is one of the powerful sources of radio and X-ray emission consisting of an accreting compact object, probably a black hole, with a Wolf-Rayet star companion. Based on the detections of ultra high energy gamma-rays by Kiel and Havera Park, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of long-term observations of the Cyg X-3 binary at energies 800 GeV–85 TeV detected by SHALON in 1995 are presented with images, integral spectra and spectral energy distribution. The identification of source with Cygnus X-3 detected by SHALON was secured by the detection of its 4.8 hour orbital period in TeV gamma-rays. During the whole observation period of Cyg X-3 with SHALON significant flux increases were detected at energies above 0.8 TeV. These TeV flux increases are correlated with flaring activity at a lower energy range of X-ray and/or at observations of Fermi LAT as well as with radio emission from the relativistic jets of Cygnus X-3. The variability of very high-energy gamma-radiation and correlation of radiation activity in the wide energy range can provide essential information on particle mechanism production up to very high energies. Whereas, modulation of very high energy emission connected to the orbital motion of the binary system, provides an understanding of the emission processes, nature and location of particle acceleration.

  15. Particle acceleration in binaries

    Science.gov (United States)

    Sinitsyna, V. G.; Sinitsyna, V. Y.

    2017-06-01

    Cygnus X-3 massive binary system is one of the powerful sources of radio and X-ray emission consisting of an accreting compact object, probably a black hole, with a Wolf-Rayet star companion. Based on the detections of ultra high energy gamma-rays by Kiel and Havera Park, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of long-term observations of the Cyg X-3 binary at energies 800 GeV-85 TeV detected by SHALON in 1995 are presented with images, integral spectra and spectral energy distribution. The identification of source with Cygnus X-3 detected by SHALON was secured by the detection of its 4.8 hour orbital period in TeV gamma-rays. During the whole observation period of Cyg X-3 with SHALON significant flux increases were detected at energies above 0.8 TeV. These TeV flux increases are correlated with flaring activity at a lower energy range of X-ray and/or at observations of Fermi LAT as well as with radio emission from the relativistic jets of Cygnus X-3. The variability of very high-energy gamma-radiation and correlation of radiation activity in the wide energy range can provide essential information on particle mechanism production up to very high energies. Whereas, modulation of very high energy emission connected to the orbital motion of the binary system, provides an understanding of the emission processes, nature and location of particle acceleration.

  16. Particle accelerator; the Universe machine

    CERN Multimedia

    Yurkewicz, Katie

    2008-01-01

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

  17. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

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

  18. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

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

  19. Nonlinear dynamics in particle accelerators

    CERN Document Server

    Dilão, Rui

    1996-01-01

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

  20. Superconducting Magnets for Particle Accelerators

    CERN Document Server

    Bottura, Luca; Yamamoto, Akira; Zlobin, Alexander V

    2016-01-01

    In this paper we summarize the evolution and contributions of superconducting magnets to particle accelerators as chronicled over the last 50 years of Particle Accelerator Conferences (PAC, NA-PAC and IPAC). We begin with an historical overview based primarily on PAC Proceedings augmented with references to key milestones in the development of superconducting magnets for particle accelerators. We then provide some illustrative examples of applications that have occurred over the past 50 years, focusing on those that have either been realized in practice or provided technical development for other projects, with discussion of possible future applications.

  1. State of accelerator for therapy

    CERN Document Server

    Maruhashi, A

    2002-01-01

    21 facilities carry out particle radiotherapy in the world and 6 facilities will start in the next year. They are shown in the table. 6 facilities of them exist in Japan. Small accelerator for proton therapy is developed. The area of them becomes smaller than 100 m sup 2. 5 makers, form, kinds of accelerator, length of track, beam energy of them are shown. States of particle radiotherapy in 4 facilities in Japan are explained by the kinds of particle, energy, beam intensity, time structure and radiation room. The important problems are reconsideration of building and compact rotating gantry. The problems of radiotherapy are explained. (S.Y.)

  2. Acceleration of particles in plasmas

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    The accelerating fields in radio-frequency accelerators are limited to roughly 100 MV/m due to material breakdown which occurs on the walls of the structure. In contrast, a plasma, being already ionized, can support electric fields in excess of 100 GV/m. Such high accelerating gradients hold the promise of compact particle accelerators. Plasma acceleration has been an emerging and fast growing field of research in the past two decades. In this series of lectures, we will review the principles of plasma acceleration. We will see how relativistic plasma waves can be excited using an ultra-intense laser or using a particle beam. We will see how these plasma waves can be used to accelerate electrons to high energy in short distances. Throughout the lectures, we will also review recent experimental results. Current laser-plasma experiments throughout the world have shown that monoenergetic electron beams from 100 MeV to 1 GeV can be obtained in distances ranging from the millimetre to the centimetre. Experiments a...

  3. Accelerators for charged particle therapy

    Science.gov (United States)

    Flanz, Jacob

    2015-06-01

    History has shown that energetic particles can be useful for medical applications. From the time, in 1895 when Roentgen discovered X-rays, and in 1913 when Coolidge developed the vacuum X-ray tube, energetic particles have been an important tool for medicine. Development of the appropriate tool for effective and safe radiotherapy requires an in-depth understanding of the application and constraints. Various solutions are possible and choices must be analyzed on the basis of the suitability for meeting the requirements. Some of the requirements of charged particle therapy are summarized and various accelerator options are described and discussed.

  4. Non-Linear Transmission Line (NLTL) Microwave Source Lecture Notes the United States Particle Accelerator School

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Steven J. [Los Alamos National Laboratory; Carlsten, Bruce E. [Los Alamos National Laboratory

    2012-06-26

    We will quickly go through the history of the non-linear transmission lines (NLTLs). We will describe how they work, how they are modeled and how they are designed. Note that the field of high power, NLTL microwave sources is still under development, so this is just a snap shot of their current state. Topics discussed are: (1) Introduction to solitons and the KdV equation; (2) The lumped element non-linear transmission line; (3) Solution of the KdV equation; (4) Non-linear transmission lines at microwave frequencies; (5) Numerical methods for NLTL analysis; (6) Unipolar versus bipolar input; (7) High power NLTL pioneers; (8) Resistive versus reactive load; (9) Non-lineaer dielectrics; and (10) Effect of losses.

  5. 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...

  6. Electrophysical Systems Based On Charged Particle Accelerators

    CERN Document Server

    Vorogushin, M F

    2004-01-01

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

  7. Accelerator Technology: Geodesy and Alignment for Particle Accelerators

    CERN Document Server

    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

  8. Radiation-resistant fibre for particle accelerator

    CERN Multimedia

    2007-01-01

    "Radiation-resistant optical fibre is being used by CERN, the European Laboratory for Particle Physics, in the world's largest particle accelerator, the Large Hadron Collider (LHC) near Geneva." (1 page)

  9. Particle acceleration in a plasma filled IFEL

    Science.gov (United States)

    Gürsey, Yusuf

    1989-10-01

    An earlier proposal by J. L. Bobin1,2 to accelerate particles using a laser, undulator magnet, particle beam, and plasma is elaborated upon. The current status of research on the subject is presented, including problems and prospects. Estimates are given for parameters of an experiment at the Accelerator Test Facility at Brookhaven National Laboratory.

  10. Solar energetic particles: Acceleration and transport

    Science.gov (United States)

    Cliver, Edward W.

    2000-06-01

    This paper reviews highlights of the 26th ICRC in the area of acceleration and propagation of solar energetic particles (SEPs). New results on SEP charge state and composition, a lively topic during the Conference, are covered in an accompanying paper by Klecker. I begin with a brief historical review of the field to provide context for the key advances/developments on SEP acceleration/propagation presented in Salt Lake City. These include: (1) the use of gamma-ray emissions as diagnostics of the acceleration process(es) and probes of the interaction region; (2) the observation of ~10 GeV (or higher) protons for the 6 November 1997 ground level event by the Milagrito experiment; (3) observations of coronal Moreton waves as ``smoking pistols'' of shock acceleration/injection of SEPs; (4) an investigation of the role of proton event spectra in the current ``two-class'' picture of SEP events; (5) an analysis of the Gnevyshev Gap in SEP activity; (6) a Ulysses-based determination of the dependence of SEP mean free path on radial distance from the Sun and on heliographic latitude, and (7) an examination of the dissipation range in the power spectrum of interplanetary magnetic field fluctuations. I conclude with a discussion of new instrumentation (e.g., Milagro, HESSI) and a look to the expected level of SEP activity for the approaching maximum of solar cycle 23. .

  11. Ultimate gradient in solid-state accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, D.H.

    1998-08-01

    The authors recall the motivation for research in high-gradient acceleration and the problems posed by a compact collider. They summarize the phenomena known to appear in operation of a solid-state structure with large fields, and research relevant to the question of the ultimate gradient. They take note of new concepts, and examine one in detail, a miniature particle accelerator based on an active millimeter-wave circuit and parallel particle beams.

  12. Diffraction Accelerator Of Charged Particles

    CERN Document Server

    Alekseev, Yu K; Kosarev, A A; Poseryaev, A V; Shvedunov, V I; Vetrov, A A; Zayarniy, D A

    2004-01-01

    We present the results of theoretical and numerical analysis of the physical processes for laser linear accelerator based on two symmetric resonance diffraction gratings with double-sided accelerating field excitation. Structures parameters optimization provides π-mode field amplitude distribution in neighboring diffraction zone. The maximum energy gradient restricted by ablation processes in grating materials is estimated as 1-3 GeV/m. The numerical analyses and analytical approximation of electric and magnetic field structures are done, longitudinal and transverse electron beam dynamics in accelerating systems are considered, wake fields and focusing properties of diffraction gratings are estimated.

  13. Global particle accelerator gets the big chill

    CERN Multimedia

    Sherriff, Lucy

    2004-01-01

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

  14. Lauch of CERN particle accelerator delayed

    CERN Multimedia

    2007-01-01

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

  15. Superconducting Magnets for Particle Accelerators

    CERN Document Server

    Rossi, L

    2012-01-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    CERN Document Server

    Plettner, Tomas; Spencer, James; Wisdom, Jeffrey

    2005-01-01

    Laser driven particle accelerators based on the current generation of lasers will require sub-micron control of the laser field as well as precise beam guiding. Hence the fabrication techniques that allow integrating both elements into an accelerator-on-chip format become critical for the success of such particle accelerators. Micromachining technology for silicon has been shown to be one such feasible technology in PAC2003 but with a variety of complications on the laser side. Fortunately, in recent years the fabrication of transparent ceramics has become an interesting technology that could be applied for laser-particle accelerators in several ways. We discuss this area, its advantages such as the range of materials it provides and various ways to implement it followed by some different test examples that have been considered. One important goal of this approach is an integrated system that could avoid the necessity of having to inject either laser or particle pulses into these structures.

  18. Massive particle accelerator revving up

    CERN Multimedia

    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)

  19. A New Paradigm for Flare Particle Acceleration

    Science.gov (United States)

    Guidoni, Silvina E.; Karpen, Judith T.; DeVore, C. Richard

    2017-08-01

    The mechanism that accelerates particles to the energies required to produce the observed high-energy impulsive emission and its spectra in solar flares is not well understood. Here, we propose a first-principle-based model of particle acceleration that produces energy spectra that closely resemble those derived from hard X-ray observations. Our mechanism uses contracting magnetic islands formed during fast reconnection in solar flares to accelerate electrons, as first proposed by Drake et al. (2006) for kinetic-scale plasmoids. We apply these ideas to MHD-scale islands formed during fast reconnection in a simulated eruptive flare. A simple analytic model based on the particles’ adiabatic invariants is used to calculate the energy gain of particles orbiting field lines in our ultrahigh-resolution, 2.5D, MHD numerical simulation of a solar eruption (flare + coronal mass ejection). Then, we analytically model electrons visiting multiple contracting islands to account for the observed high-energy flare emission. Our acceleration mechanism inherently produces sporadic emission because island formation is intermittent. Moreover, a large number of particles could be accelerated in each macroscopic island, which may explain the inferred rates of energetic-electron production in flares. We conclude that island contraction in the flare current sheet is a promising candidate for electron acceleration in solar eruptions. This work was supported in part by the NASA LWS and H-SR programs..

  20. Anisotropic Particle Acceleration in Relativistic Shear Layers

    Science.gov (United States)

    Boettcher, Markus; Liang, Edison P.; Fu, Wen

    2017-08-01

    We present results of Particle in Cell (PIC) simulations of relativistic shear layers as relevant to the relativistic jets of acive galactic nuclei and gamma-ray bursts. We study the self-generation of electro-magnetic fields and particle acceleration for various different plasma compositions (electron-ion vs. electron-positron pair vs. hybrid). Special emphasis is placed on the angular distribution of accelerated particles. We find that electron-ion shear layers lead to highly anisotropic particle distributions in the frame of the fast-moving inner spine. The beaming pattern of the highest-energy particles is much narrower than the characteristic beaming angle of 1/Gamma resulting from relativistic aberration of a co-moving isotropic distribution. This may pose a possible solution to the Lorentz-Factor crisis in blazars and explain very hard X-ray / soft gamma-ray spectra of some gamma-ray bursts.

  1. Machine Protection: Availability for Particle Accelerators

    CERN Document Server

    Apollonio, Andrea; Schmidt, Ruediger

    2015-03-16

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

  2. Pulsed power accelerators for particle beam fusion

    Science.gov (United States)

    Martin, T. H.; Barr, G. W.; Vandevender, J. P.; White, R. A.; Johnson, D. L.

    1980-05-01

    Sandia National Laboratories is completing the construction phase of the Particle Beam Fusion Accelerator-1 (PBFA-1). Testing of the 36 module, 30 TW, 1 MJ output accelerator is in the initial stages. The 4 MJ, PBFA Marx generator provided 3.6 MA into water-copper sulfate load resistors with a spread from first to last Marx firing between 15 to 25 ns and an output power of 5.7 TW. This accelerator is a modular, lower voltage, pulsed power device that is capable of scaling to power levels exceeding 100 TW. The elements of the PBFA technology and their integration into an accelerator system for particle beam fusion is discussed.

  3. 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.

  4. Applications of Particle Accelerators in Medical Physics

    CERN Document Server

    Cuttone, G

    2008-01-01

    Particle accelerators are often associated to high energy or nuclear physics. As well pointed out in literature [1] if we kindly analyse the number of installation worldwide we can easily note that about 50% is mainly devoted to medical applications (radiotherapy, medical radioisotopes production, biomedical research). Particle accelerators are also playing an important indirect role considering the improvement of the technical features of medical diagnostic. In fact the use of radionuclide for advanced medical imaging is strongly increasing either in conventional radiography (CT and MRI) and also in nuclear medicine for Spect an PET imaging. In this paper role of particle accelerators for medical applications will be presented together with the main solutions applied.

  5. Energetic particle acceleration in spherically symmetric accretion flows and shocks

    Science.gov (United States)

    Webb, G. M.; Bogdan, T. J.

    1987-01-01

    Steady state, spherically symmetric solutions of the cosmic-ray transport equation describing the acceleration of energetic particles in galactic accretion flows onto neutron stars, black holes, white dwarfs, and protostars are studied. The results indicate that astrophysical accretion flows can be partitioned into distinct classes depending upon whether the accretion rate lies above or below a critical value of a few times 10 to the -7th stellar masses/yr. When the particle transport is convection-dominated, both classes of accretion flows exhibit a spectral index appropriate for first-order Fermi acceleration at a plane shock in the absence of losses. As the particle transport becomes diffusion-dominated, both classes show a break and precipitous falloff in the particle spectrum due to the escape of these particles from the accretion flow. The precise nature of the spectrum depends on the relationship between the particle momentum and the spatial diffusion coefficient.

  6. 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.

  7. A particle accelerator probes artifacts

    CERN Document Server

    Dran, J C; Salomon, J

    2002-01-01

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

  8. RFQ device for accelerating particles

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-01-01

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

  9. RFQ device for accelerating particles

    Science.gov (United States)

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

    1995-06-06

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

  10. Neural Networks for Modeling and Control of Particle Accelerators

    Science.gov (United States)

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

    2016-04-01

    Particle accelerators are host to myriad nonlinear and complex physical phenomena. They often involve a multitude of interacting systems, are subject to tight performance demands, and should be able to run for extended periods of time with minimal interruptions. Often times, traditional control techniques cannot fully meet these requirements. One promising avenue is to introduce machine learning and sophisticated control techniques inspired by artificial intelligence, particularly in light of recent theoretical and practical advances in these fields. Within machine learning and artificial intelligence, neural networks are particularly well-suited to modeling, control, and diagnostic analysis of complex, nonlinear, and time-varying systems, as well as systems with large parameter spaces. Consequently, the use of neural network-based modeling and control techniques could be of significant benefit to particle accelerators. For the same reasons, particle accelerators are also ideal test-beds for these techniques. Many early attempts to apply neural networks to particle accelerators yielded mixed results due to the relative immaturity of the technology for such tasks. The purpose of this paper is to re-introduce neural networks to the particle accelerator community and report on some work in neural network control that is being conducted as part of a dedicated collaboration between Fermilab and Colorado State University (CSU). 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-06-07

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

  12. Flow Laminarization and Acceleration by Suspended Particles

    NARCIS (Netherlands)

    Bertsch, M.; Hulshof, J.; Prostokishin, V.M.

    2015-01-01

    In [Comm. Appl. Math. Comput. Sci., 4(2009), pp. 153-175], Barenblatt presents a model for partial laminarization and acceleration of shear flows by the presence of suspended particles of different sizes, and provides a formal asymptotic analysis of the resulting velocity equation. In the present

  13. AXEL-2016: Introduction to Particle Accelerators

    CERN Document Server

    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...

  14. Big magnet glitch at world's top particle accelerator

    CERN Multimedia

    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)

  15. Cryogenics for Particle Accelerators and Detectors

    CERN Document Server

    Lebrun, P; Vandoni, Giovanna; Wagner, U

    2002-01-01

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

  16. Acceleration and Propagation of Solar Energetic Particles

    Science.gov (United States)

    Klein, Karl-Ludwig; Dalla, Silvia

    2017-11-01

    Solar Energetic Particles (SEPs) are an important component of Space Weather, including radiation hazard to humans and electronic equipment, and the ionisation of the Earth's atmosphere. We review the key observations of SEPs, our current understanding of their acceleration and transport, and discuss how this knowledge is incorporated within Space Weather forecasting tools. Mechanisms for acceleration during solar flares and at shocks driven by Coronal Mass Ejections (CMEs) are discussed, as well as the timing relationships between signatures of solar eruptive events and the detection of SEPs in interplanetary space. Evidence on how the parameters of SEP events are related to those of the parent solar activity is reviewed and transport effects influencing SEP propagation to near-Earth locations are examined. Finally, the approaches to forecasting Space Weather SEP effects are discussed. We conclude that both flare and CME shock acceleration contribute to Space Weather relevant SEP populations and need to be considered within forecasting tools.

  17. 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.

  18. AXEL–2014: Introduction to Particle Accelerators

    CERN Multimedia

    2014-01-01

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

  19. 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

  20. Innovative Digitally Controlled Particle Accelerator Magnet Power Supply

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup; Bidoggia, Benoit; Maheshwari, Ram Krishan

    2013-01-01

    Particle accelerator magnet power supplies needs to be extremely precise. A new and innovative power supply for particle accelerator magnets is proposed. The topologies for the input and the output converter are shown and the control architecture is described.......Particle accelerator magnet power supplies needs to be extremely precise. A new and innovative power supply for particle accelerator magnets is proposed. The topologies for the input and the output converter are shown and the control architecture is described....

  1. Radiation from Shock-Accelerated Particles

    Science.gov (United States)

    Nishikawa, Ken-ichi; Choi, E. J.; Min, K. W.; Niemiec, J.; Zhang, B.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Nordlund, A.; Frederiksen, J.; hide

    2012-01-01

    Plasma instabilities excited in collisionless shocks are responsible for particle acceleration, generation of magnetic fields , and associated radiation. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. The shock structure depends on the composition of the jet and ambient plasma (electron-positron or electron-ions). Strong electromagnetic fields are generated in the reverse , jet shock and provide an emission site. These magnetic fields contribute to the electron's transverse deflection behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. The detailed properties of the radiation are important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jet shocks, and supernova remnants

  2. Summary of completed project. [Particle acceleration during solar flares: Particle interactions with ambient plasma

    Science.gov (United States)

    Petrosian, Vahe

    1991-01-01

    The primary goal of the work in this proposal has been the determination of the requirement for acceleration of particles, especially electrons, during solar flares. This is one of the important and yet unsolved problems in solar flares and other astronomical objects. This is done by detailed theoretical investigation of interaction of accelerated particles with ambient plasma including interaction with particles, waves, and large scale magnetic fields. Comparison with observed impulsive phase radiation such as X-rays, gamma-rays, microwaves, and type III radiation is used for constraining the models and for determination of the characteristics of the accelerated particles. Steady state and time-dependent numerical codes have been developed based on the Fokker-Planck method for study of the particle acceleration and transport during a flare. Using these, the correlation between characteristics of radiation at various wavelengths have been investigated and some constraints have been set on the model parameters. During the last three year period of this grant, dissertation research of three graduate students have been partially supported by this grant. Each of these theses has dealt with various observed properties of flare emission with particular emphasis on the interrelationship between radiation in at least two energy bands: X-rays and gamma-rays, X-rays and microwaves, and X-rays and type III radiation. This has allowed considerable tightening of constraints on models, and inclusion of wave particle interaction has allowed direct calculations of acceleration processes.

  3. Particle drift, diffusion, and acceleration at shocks

    Science.gov (United States)

    Jokipii, J. R.

    1982-01-01

    The gradient and curvature drifts implicit in change of the ambient magnetic field at a hydromagnetic shock wave are incorporated into the diffusive theory of shock acceleration of charged particles. The conventional jump condition at the shock is modified by a term incorporating the large drift along the shock plane. This term vanished identically for one-dimensional systems, but must be included in general for shocks which are finite in transverse extent or which have transverse structure. It is found that the effect of the drift is such that the transverse drift rate is proportional to the acceleration rate, and for perpendicular shocks is exactly equal to the rate of change of energy in the V x B electric field observed in the shock frame. This establishes a connection with the 'shock drift' models which neglect diffusion.

  4. ION SOURCE FOR A SINGLE PARTICLE ACCELERATOR

    Directory of Open Access Journals (Sweden)

    Tomas Matlocha

    2016-12-01

    Full Text Available This paper proposes a method to obtain very low beam current on the injection side of an particle accelerator. By using a combination of a well known ion source type and a short photo-emissive laser pulse, very low amount of ions can be created. The method could be used in the ion source of various types of the accelerators, where very low beam current is essential. The design is adapted to build a compact internal ion source and the dimensions of the device are adjusted to fit central region of the cyclotron U-120M. The functional parameters of the device are discussed and the ammount of the produced ions is estimated.

  5. Superconducting magnet technology for particle accelerators and detectors seminar

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    This lecture is an introduction to superconducting magnets for particle accelerators and detectors, the aim being to explain the vocabulary and describe the basic technology of modern superconducting magnets, and to explore the limits of the technology. It will include the following: - Why we need superconducting magnets - Properties of superconductors, critical field, critical temperature - Why accelerators need fine filaments and cables; conductor manufacture - Temperature rise and temperature margin: the quench process, training - Quench protection schemes. Protection in the case of the LHC. - Magnets for detectors - The challenges of state-of-the-art magnets for High Energy Physics

  6. Quantum Ground States as Equilibrium Particle-Vacuum Interaction States

    CERN Document Server

    Puthoff, Harold E

    2012-01-01

    A remarkable feature of atomic ground states is that they are observed to be radiationless in nature, despite (from a classical viewpoint) typically involving charged particles in accelerated motions. The simple hydrogen atom is a case in point. This universal groundstate characteristic is shown to derive from particle-vacuum interactions in which a dynamic equilibrium is established between radiation emission due to particle acceleration, and compensatory absorption from the zero-point fluctuations of the vacuum electromagnetic field. The result is a net radiationless ground state. This principle constitutes an overarching constraint that delineates an important feature of quantum ground states.

  7. Acceleration of superparamagnetic particles with magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Stange, R., E-mail: Robert.stange@tu-dresden.de; Lenk, F.; Bley, T.; Boschke, E.

    2017-04-01

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

  8. Production and applications of neutrons using particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-01

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

  9. Particle Acceleration in the Heliosphere: Implications for Astrophysics

    Science.gov (United States)

    Fisk, L. A.; Gloeckler, G.

    2012-11-01

    There has been a remarkable discovery concerning particles that are accelerated in the solar wind. At low energies, in the region where the particles are being accelerated, the spectrum of the accelerated particles is always the same: when expressed as a distribution function, the spectrum is a power law in particle speed with a spectral index of -5, and a rollover at higher particle speeds that can often be described as exponential. This common spectral shape cannot be accounted for by any conventional acceleration mechanism, such as diffusive shock acceleration or traditional stochastic acceleration. It has thus been necessary to invent a new acceleration mechanism to account for these observations, a pump mechanism in which particles are pumped up in energy through a series of adiabatic compressions and expansions. The conditions under which the pump acceleration is the dominant acceleration mechanism are quite general and are likely to occur in other astrophysical plasmas. In this paper, the most compelling observations of the -5 spectra are reviewed; the governing equation of the pump acceleration mechanism is derived in detail; the pump acceleration mechanism is applied to acceleration at shocks; and, as an illustration of the potential applicability of the pump acceleration mechanism to other astrophysical plasmas, the pump mechanism is applied to the acceleration of galactic cosmic rays in the interstellar medium.

  10. 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.

  11. A theoretical perspective on particle acceleration by interplanetary shocks and the Solar Energetic Particle problem

    Science.gov (United States)

    Verkhoglyadova, Olga P.; Zank, Gary P.; Li, Gang

    2015-02-01

    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 particle

  12. Connecting inflation with late cosmic acceleration by particle production

    CERN Document Server

    Nunes, Rafael C

    2016-01-01

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

  13. Space charge physics for particle accelerators

    CERN Document Server

    Hofmann, Ingo

    2017-01-01

    Understanding and controlling the physics of space charge effects in linear and circular proton and ion accelerators are essential to their operation, and to future high-intensity facilities. This book presents the status quo of this field from a theoretical perspective, compares analytical approaches with multi-particle computer simulations and – where available – with experiments. It discusses fundamental concepts of phase space motion, matched beams and modes of perturbation, along with mathematical models of analysis – from envelope to Vlasov-Poisson equations. The main emphasis is on providing a systematic description of incoherent and coherent resonance phenomena; parametric instabilities and sum modes; mismatch and halo; error driven resonances; and emittance exchange due to anisotropy, as well as the role of Landau damping. Their distinctive features are elaborated in the context of numerous sample simulations, and their potential impacts on beam quality degradation and beam loss are discussed....

  14. A Magnetostrictive Tuning System for Particle Accelerators

    CERN Document Server

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

    2005-01-01

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

  15. A Magnetorestrictive Tuning System for Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-05-16

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

  16. Turbulent Particle Acceleration in the Diffuse Cluster Plasma

    OpenAIRE

    Eilek, J. A.; Weatherall, J. C.

    1999-01-01

    In situ particle acceleration is probably occuring in cluster radio haloes. This is suggested by the uniformity and extent of the haloes, given that spatial diffusion is slow and that radiative losses limit particle lifetimes. Stochastic acceleration by plasma turbulence is the most likely mechanism. Alfven wave turbulence has been suggested as the means of acceleration, but it is too slow to be important in the cluster environment. We propose, instead, that acceleration occurs via strong low...

  17. Solar flare particle acceleration in collapsing magnetic traps

    OpenAIRE

    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...

  18. Beam-driven, Plasma-based Particle Accelerators

    CERN Document Server

    Muggli, P.

    2016-01-01

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

  19. 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......, and subsequently the particle separates from the cavity. The cavity growth and particle detachment are modeled by considering the momentum of the particle and the displaced liquid. The analysis suggests that all particles which cause cavitation are accelerated into translatory motion, and separate from...... the cavities they themselves nucleate. Thus, in the research of cavitation nuclei the link is established between developed cavitation bubbles and their origin....

  20. Neural Networks for Modeling and Control of Particle Accelerators

    CERN Document Server

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

    2016-01-01

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

  1. Laser-driven particle acceleration towards radiobiology and medicine

    CERN Document Server

    2016-01-01

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

  2. Particle Acceleration in Dissipative Pulsar Magnetospheres

    Science.gov (United States)

    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.

  3. Grid Connected Power Supplies for Particle Accelerator Magnets

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup

    Power supplies play a large role in particle accelerators, for creating, accelerating, steering and shaping the beam. This thesis covers the power supplies for steering and shaping the beam, namely the magnet power supplies. These power supplies have a special set of requirements regarding output...... and smaller converter size. A high efficiency converter based on Silicon Carbide switching devices is also presented exhibiting above 96 % efficiency for the entire power range. Finally reliability issues are considered as the reliability of a particle accelerator supply is of utmost importance. Particle...... accelerators requires large up time and many power supplies, magnets etc. must function in parallel for the particle accelerator to operate. A method for increasing the reliability of the proposed converter is shown. This is done by creating a lifetime model for the power module converter together...

  4. Analysis of powerful local acceleration of solar wind particles

    Science.gov (United States)

    Molotkov, I. A.; Ryabova, N. A.

    2017-07-01

    Collisionless plasma of the solar wind is considered. A number of physical processes in this plasma lead to the formation of magnetic islands that are potential traps for charged particles. The merging and contractions of magnetic islands cause a powerful acceleration of these particles to energies over 1 MeV. This work continues the study in recent years on modeling of the acceleration of charged particles of the solar wind. Our analytical solution of the transport equations allowed us to find the exact number of particles with energies exceeding given level.

  5. PARTICLE ACCELERATION IN SUPERLUMINAL STRONG WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Teraki, Yuto; Ito, Hirotaka; Nagataki, Shigehiro, E-mail: yuto.teraki@riken.jp [Astrophysical Big Bang Laboratory, RIKEN, Saitama 351-0198 (Japan)

    2015-06-01

    We calculate the electron acceleration in random superluminal strong waves (SLSWs) and radiation from them using numerical methods in the context of the termination shocks of pulsar wind nebulae. We pursue the orbit of electrons by solving the equation of motion in the analytically expressed electromagnetic turbulences. These consist of a primary SLS and isotropically distributed secondary electromagnetic waves. Under the dominance of the secondary waves, all electrons gain nearly equal energy. On the other hand, when the primary wave is dominant, selective acceleration occurs. The phase of the primary wave for electrons moving nearly along the wavevector changes very slowly compared with the oscillation of the wave, which is “phase-locked,” and such electrons are continuously accelerated. This acceleration by SLSWs may play a crucial role in pre-shock acceleration. In general, the radiation from the phase-locked population is different from the synchro-Compton radiation. However, when the amplitude of the secondary waves is not extremely weaker than that of the primary wave, the typical frequency can be estimated from synchro-Compton theory using the secondary waves. The primary wave does not contribute to the radiation because the SLSW accelerates electrons almost linearly. This radiation can be observed as a radio knot at the upstream of the termination shocks of the pulsar wind nebulae without counterparts in higher frequency ranges.

  6. Particle Acceleration in Superluminal Strong Waves

    Science.gov (United States)

    Teraki, Yuto; Ito, Hirotaka; Nagataki, Shigehiro

    2015-06-01

    We calculate the electron acceleration in random superluminal strong waves (SLSWs) and radiation from them using numerical methods in the context of the termination shocks of pulsar wind nebulae. We pursue the orbit of electrons by solving the equation of motion in the analytically expressed electromagnetic turbulences. These consist of a primary SLS and isotropically distributed secondary electromagnetic waves. Under the dominance of the secondary waves, all electrons gain nearly equal energy. On the other hand, when the primary wave is dominant, selective acceleration occurs. The phase of the primary wave for electrons moving nearly along the wavevector changes very slowly compared with the oscillation of the wave, which is “phase-locked,” and such electrons are continuously accelerated. This acceleration by SLSWs may play a crucial role in pre-shock acceleration. In general, the radiation from the phase-locked population is different from the synchro-Compton radiation. However, when the amplitude of the secondary waves is not extremely weaker than that of the primary wave, the typical frequency can be estimated from synchro-Compton theory using the secondary waves. The primary wave does not contribute to the radiation because the SLSW accelerates electrons almost linearly. This radiation can be observed as a radio knot at the upstream of the termination shocks of the pulsar wind nebulae without counterparts in higher frequency ranges.

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

    CERN Document Server

    D'Arras, Horace

    2010-01-01

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

  8. Scientists confirm delay in testing new CERN particle accelerator

    CERN Multimedia

    2007-01-01

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

  9. 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.

  10. A simplified model for the acceleration of cosmic ray particles

    Energy Technology Data Exchange (ETDEWEB)

    Groen, Oeyvind [Oslo University College, Faculty of Engineering, PO Box 4, St. Olavs Plass, N-0130 Oslo (Norway)

    2010-03-15

    Two important questions concerning cosmic rays are: Why are electrons in the cosmic rays less efficiently accelerated than nuclei? How are particles accelerated to great energies in ultra-high energy cosmic rays? In order to answer these questions we construct a simple model of the acceleration of a charged particle in the cosmic ray. It is not meant as a detailed model, which is expected to be rather complicated, but rather as a 'pedagogic model' pointing out some important elements of a more complete model. Furthermore, the present model is sufficiently simple that it may be suitable as an 'astrophysical example' in the teaching of the special theory of relativity. In this model a particle is accelerated by ultrarelativistic shocks in a source of gamma ray bursts. No assumption as to the details of the accelerating mechanism is made except that the force acting on a charged particle depends only upon the charge of the particle and not upon its mass, and the product of the force and the thickness of the shock waves must be sufficiently great. It is important for the success of the model that the energy radiated by the particles is taken mainly from the Schott energy and not from the kinetic energy of the particles. It is shown how this model of the accelerating process can explain why electrons are accelerated to less energy than protons and heavier nuclei. The mechanism also explains how particles may be accelerated to energies greater than 10{sup 20} eV.

  11. High energy particle acceleration in solar flares Observational evidence

    Science.gov (United States)

    Chupp, E. L.

    1983-01-01

    The recent gamma ray and neutron observations made by the SMM Gamma Ray Spectrometer are reviewed. The implication these observations hold for understanding particle acceleration in solar flares are discussed. The data require that both electrons and ions must be accelerated together to relativistic energies and interact with matter in a time scale of seconds.

  12. Accelerating research into the Higgs boson particle

    CERN Multimedia

    Nikolaidou, Rosy

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

  13. Stable charged-particle acceleration and focusing in a laser accelerator using spatial harmonics.

    Science.gov (United States)

    Naranjo, B; Valloni, A; Putterman, S; Rosenzweig, J B

    2012-10-19

    Regarding the laser-driven acceleration of charged particles in photonic systems, a central unmet challenge is the achievement of simultaneous transverse and longitudinal stability at nonultrarelativistic energies. At such energies, Earnshaw's theorem [S. Earnshaw, Trans. Cambridge Philos. Soc. 7, 97 (1842)] indicates that a synchronous accelerating wave gives a defocusing effect. We present a scheme in which particles are accelerated by interaction with a resonant spatial harmonic and are focused by strong ponderomotive interaction with nonresonant spatial harmonics. We show that this scheme exhibits net transverse focusing and longitudinal stability, and we discuss its use in a compact laser accelerator.

  14. Physics of new methods of charged particle acceleration collective effects in dense charged particle ensembles

    CERN Document Server

    Bonch-Osmolovsky, A G

    1994-01-01

    This volume discusses the theory of new methods of charged particle acceleration and its physical and mathematical descriptions. It examines some collective effects in dense charged particle ensembles, and traces the history of the development of the field of accelerator physics.

  15. U of C site vies for new particle accelerator

    CERN Multimedia

    Ahmed, Usman

    2006-01-01

    "American dominance in the study and development of high-energy particle physics may be seriously compromised, according to a report issued by the National Academy of Sciences, unless efforts are made to ensure that the next high-energy particle accelerator - the International Linear Collider (ILC) - will be constructed in the U.S.

  16. Particle Acceleration and Fractional Transport in Turbulent Reconnection

    Science.gov (United States)

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

    2017-11-01

    We consider a large-scale environment of turbulent reconnection that is fragmented into a number of randomly distributed unstable current sheets (UCSs), and we statistically analyze the acceleration of particles within this environment. We address two important cases of acceleration mechanisms when particles interact with the UCS: (a) electric field acceleration and (b) acceleration by reflection at contracting islands. Electrons and ions are accelerated very efficiently, attaining an energy distribution of power-law shape with an index 1–2, depending on the acceleration mechanism. The transport coefficients in energy space are estimated from test-particle simulation data, and we show that the classical Fokker–Planck (FP) equation fails to reproduce the simulation results when the transport coefficients are inserted into it and it is solved numerically. The cause for this failure is that the particles perform Levy flights in energy space, while the distributions of the energy increments exhibit power-law tails. We then use the fractional transport equation (FTE) derived by Isliker et al., whose parameters and the order of the fractional derivatives are inferred from the simulation data, and solving the FTE numerically, we show that the FTE successfully reproduces the kinetic energy distribution of the test particles. We discuss in detail the analysis of the simulation data and the criteria that allow one to judge the appropriateness of either an FTE or a classical FP equation as a transport model.

  17. A review of transport theory. [particle acceleration in astrophysical plasmas

    Science.gov (United States)

    Jones, Frank C.

    1992-01-01

    Ways in which energy change terms arise in the transport equation and how the various terms relate to the modes of energy exchange between the particles and plasma are shown. It is argued that the transport equation cannot be used to describe the initial acceleration of thermal particles by plasma shocks or relativistic shocks where the energetic particle speeds are never much greater than the flow speeds. In most other situations, it describes almost any acceleration process that can be caused by a moving plasma. It describes shock acceleration for both parallel shocks and oblique ones, and stochastic acceleration by the turbulent motion of the scatterers as well as by their motion across the magnetic field.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Xiangrong [Los Alamos National Laboratory

    2015-07-16

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

  19. Particle Acceleration Due to Coronal Non-null Magnetic Reconnection

    Science.gov (United States)

    Threlfall, James; Neukirch, Thomas; Parnell, Clare Elizabeth

    2017-03-01

    Various topological features, for example magnetic null points and separators, have been inferred as likely sites of magnetic reconnection and particle acceleration in the solar atmosphere. In fact, magnetic reconnection is not constrained to solely take place at or near such topological features and may also take place in the absence of such features. Studies of particle acceleration using non-topological reconnection experiments embedded in the solar atmosphere are uncommon. We aim to investigate and characterise particle behaviour in a model of magnetic reconnection which causes an arcade of solar coronal magnetic field to twist and form an erupting flux rope, crucially in the absence of any common topological features where reconnection is often thought to occur. We use a numerical scheme that evolves the gyro-averaged orbit equations of single electrons and protons in time and space, and simulate the gyromotion of particles in a fully analytical global field model. We observe and discuss how the magnetic and electric fields of the model and the initial conditions of each orbit may lead to acceleration of protons and electrons up to 2 MeV in energy (depending on model parameters). We describe the morphology of time-dependent acceleration and impact sites for each particle species and compare our findings to those recovered by topologically based studies of three-dimensional (3D) reconnection and particle acceleration. We also broadly compare aspects of our findings to general observational features typically seen during two-ribbon flare events.

  20. Particle acceleration by stimulated emission of radiation in cylindrical waveguide

    Science.gov (United States)

    Tian, Xiu-Fang; Wu, Cong-Feng; Jia, Qi-Ka

    2015-07-01

    In particle acceleration by stimulated emission of radiation (PASER), efficient interaction occurs when a train of micro-bunches has periodicity identical to the resonance frequency of the medium. Previous theoretical calculations based on the simplified model have only considered the energy exchange in the boundless condition. Under experimental conditions, however, the gas active medium must be guided by the metal waveguide. In this paper, we have developed a model of the energy exchange between a train of micro-bunches and a gas mixture active medium in a waveguide boundary for the first time, based on the theory of electromagnetic fields, and made detailed analysis and calculations with MathCAD. The results show that energy density can be optimized to a certain value to get the maximum energy exchange. Supported by National Natural Science Foundation of China (10675116) and Major State Basic Research Development Programme of China (2011CB808301)

  1. Advanced visualization technology for terascale particle accelerator simulations

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-11-16

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

  2. Particle accelerators inside spinning black holes.

    Science.gov (United States)

    Lake, Kayll

    2010-05-28

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

  3. Investigation of the production of promethium-147 via particle accelerator

    Science.gov (United States)

    Artun, Ozan

    2017-08-01

    In the present paper, we mainly aim to extend nuclear data of production of radionuclide promethium-147 used in nuclear battery technology due to its weak experimental measurement and theoretical calculation. Therefore, the cross-section for charged particle induced reactions on Nd target is calculated, and moreover, the reaction processes are simulated by particle accelerator with the energy range {{E}}_{{particle}} = 50 \\to 5 MeV and in the particle beam current of 20 mA to figure out yield, activity of reaction and integral yield. For a proper understanding of investigation, the obtained results are also discussed to determine the most suitable reaction and target material for the production of radionuclide promethium-147 via particle accelerator on the basis of process.

  4. Engines of discovery a century of particle accelerators

    CERN Document Server

    Sessler, Andrew

    2014-01-01

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

  5. Hysteresis effects in the cores of particle accelerator magnets

    CERN Document Server

    AUTHOR|(CDS)2086181; Schoerling, Daniel

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

  6. 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.)

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

    Science.gov (United States)

    Ganz, Jeremy C

    2014-01-01

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

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

    CERN Multimedia

    HR Department

    2011-01-01

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

  9. Particle accelerators unravel Art and Archaeology issues

    Science.gov (United States)

    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.

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

    CERN Document Server

    Kasprowicz, Grzegorz; Raich, Uli

    2011-10-04

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

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

    CERN Document Server

    Kasprowicz, G

    2011-01-01

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

  12. Particle acceleration in cosmic plasmas – paradigm change?

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-21

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

  13. Radiation from Accelerated Particles in Shocks and Reconnections

    Science.gov (United States)

    Nishikawa, K. I.; Choi, E. J.; Min, K. W.; Niemiec, J.; Zhang, B.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Nordlund, A.; Frederiksen, J.; hide

    2012-01-01

    Plasma instabilities are responsible not only for the onset and mediation of collisionless shocks but also for the associated acceleration of particles. We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection and, more generally, relativistic acceleration behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. Our initial results of a jet-ambient interaction with anti-parallelmagnetic fields show pile-up of magnetic fields at the colliding shock, which may lead to reconnection and associated particle acceleration. We will investigate the radiation in a transient stage as a possible generation mechanism of precursors of prompt emission. In our simulations we calculate the radiation from electrons in the shock region. The detailed properties of this radiation are important for understanding the complex time evolution and spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  14. JMS-based SOA monitors CERN particle accelerators

    CERN Multimedia

    Seeley, Rich

    2007-01-01

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

  15. 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...

  16. Analytic Method to Estimate Particle Acceleration in Flux Ropes

    Science.gov (United States)

    Guidoni, S. E.; Karpen, J. T.; DeVore, C. R.

    2015-01-01

    The mechanism that accelerates particles to the energies required to produce the observed high-energy emission in solar flares is not well understood. Drake et al. (2006) proposed a kinetic mechanism for accelerating electrons in contracting magnetic islands formed by reconnection. In this model, particles that gyrate around magnetic field lines transit from island to island, increasing their energy by Fermi acceleration in those islands that are contracting. Based on these ideas, we present an analytic model to estimate the energy gain of particles orbiting around field lines inside a flux rope (2.5D magnetic island). We calculate the change in the velocity of the particles as the flux rope evolves in time. The method assumes a simple profile for the magnetic field of the evolving island; it can be applied to any case where flux ropes are formed. In our case, the flux-rope evolution is obtained from our recent high-resolution, compressible 2.5D MHD simulations of breakout eruptive flares. The simulations allow us to resolve in detail the generation and evolution of large-scale flux ropes as a result of sporadic and patchy reconnection in the flare current sheet. Our results show that the initial energy of particles can be increased by 2-5 times in a typical contracting island, before the island reconnects with the underlying arcade. Therefore, particles need to transit only from 3-7 islands to increase their energies by two orders of magnitude. These macroscopic regions, filled with a large number of particles, may explain the large observed rates of energetic electron production in flares. We conclude that this mechanism is a promising candidate for electron acceleration in flares, but further research is needed to extend our results to 3D flare conditions.

  17. Implementation and performance of FPGA-accelerated particle flow filter

    Science.gov (United States)

    Charalampidis, Dimitrios; Jilkov, Vesselin P.; Wu, Jiande

    2015-09-01

    The particle flow filters, proposed by Daum & Hwang, provide a powerful means for density-based nonlinear filtering but their computation is intense and may be prohibitive for real-time applications. This paper proposes a design for superfast implementation of the exact particle flow filter using a field-programmable gate array (FPGA) as a parallel environment to speedup computation. Simulation results from a nonlinear filtering example are presented to demonstrate that using FPGA can dramatically accelerate particle flow filters through parallelization at the expense of a tolerable loss in accuracy as compared to nonparallel implementation.

  18. Can Substorm Particle Acceleration Be Applied to Solar Flares?

    Science.gov (United States)

    Birn, J.; Battaglia, M.; Fletcher, L.; Hesse, M.; Neukirch, T.

    2017-10-01

    Using test particle studies in the electromagnetic fields of three-dimensional magnetohydrodynamic (MHD) simulations of magnetic reconnection, we study the energization of charged particles in the context of the standard two-ribbon flare picture in analogy to the standard magnetospheric substorm paradigm. In particular, we investigate the effects of the collapsing field (“collapsing magnetic trap”) below a reconnection site, which has been demonstrated to be the major acceleration mechanism that causes energetic particle acceleration and injections observed in Earth’s magnetotail associated with substorms and other impulsive events. We contrast an initially force-free, high-shear field (low beta) with low and moderate shear, finite-pressure (high-beta) arcade structures, where beta represents the ratio between gas (plasma) and magnetic pressure. We demonstrate that the energization affects large numbers of particles, but the acceleration is modest in the presence of a significant shear field. Without incorporating loss mechanisms, the effect on particles at different energies is similar, akin to adiabatic heating, and thus is not a likely mechanism to generate a power-law tail onto a (heated or not heated) Maxwellian velocity distribution.

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

    CERN Multimedia

    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...

  20. Accurate and efficient spin integration for particle accelerators

    Directory of Open Access Journals (Sweden)

    Dan T. Abell

    2015-02-01

    Full Text Available Accurate spin tracking is a valuable tool for understanding spin dynamics in particle accelerators and can help improve the performance of an accelerator. In this paper, we present a detailed discussion of the integrators in the spin tracking code gpuSpinTrack. We have implemented orbital integrators based on drift-kick, bend-kick, and matrix-kick splits. On top of the orbital integrators, we have implemented various integrators for the spin motion. These integrators use quaternions and Romberg quadratures to accelerate both the computation and the convergence of spin rotations. We evaluate their performance and accuracy in quantitative detail for individual elements as well as for the entire RHIC lattice. We exploit the inherently data-parallel nature of spin tracking to accelerate our algorithms on graphics processing units.

  1. 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.

  2. 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.

  3. Support vector machine based on adaptive acceleration particle swarm optimization.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Matthaeus, W.

    1992-01-01

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

  5. Advanced Accelerators: Particle, Photon and Plasma Wave Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Ronald L. [Florida A & M University, Tallahassee, FL (United States)

    2017-06-29

    The overall objective of this project was to study the acceleration of electrons to very high energies over very short distances based on trapping slowly moving electrons in the fast moving potential wells of large amplitude plasma waves, which have relativistic phase velocities. These relativistic plasma waves, or wakefields, are the basis of table-top accelerators that have been shown to accelerate electrons to the same high energies as kilometer-length linear particle colliders operating using traditional decades-old acceleration techniques. The accelerating electrostatic fields of the relativistic plasma wave accelerators can be as large as GigaVolts/meter, and our goal was to study techniques for remotely measuring these large fields by injecting low energy probe electron beams across the plasma wave and measuring the beam’s deflection. Our method of study was via computer simulations, and these results suggested that the deflection of the probe electron beam was directly proportional to the amplitude of the plasma wave. This is the basis of a proposed diagnostic technique, and numerous studies were performed to determine the effects of changing the electron beam, plasma wave and laser beam parameters. Further simulation studies included copropagating laser beams with the relativistic plasma waves. New interesting results came out of these studies including the prediction that very small scale electron beam bunching occurs, and an anomalous line focusing of the electron beam occurs under certain conditions. These studies were summarized in the dissertation of a graduate student who obtained the Ph.D. in physics. This past research program has motivated ideas for further research to corroborate these results using particle-in-cell simulation tools which will help design a test-of-concept experiment in our laboratory and a scaled up version for testing at a major wakefield accelerator facility.

  6. On the acceleration of charged particles at relativistic shock fronts

    Science.gov (United States)

    Kirk, J. G.; Schneider, P.

    1987-01-01

    The diffusive acceleration of highly relativistic particles at a shock is reconsidered. Using the same physical assumptions as Blandford and Ostriker (1978), but dropping the restriction to nonrelativistic shock velocities, the authors find approximate solutions of the particle kinetic equation by generalizing the diffusion approximation to higher order terms in the anisotropy of the particle distribution. The general solution of the transport equation on either side of the shock is constructed, which involves the solution of an eigenvalue problem. By matching the two solutions at the shock, the spectral index of the resulting power law is found by taking into account a sufficiently large number of eigenfunctions. Low-order truncation corresponds to the standard diffusion approximation and to a somewhat more general method described by Peacock (1981). In addition to the energy spectrum, the method yields the angular distribution of the particles and its spatial dependence.

  7. CAS - CERN Accelerator School: Intensity Limitations in Particle Beams

    CERN Document Server

    2017-01-01

    AbstractThis report presents the proceedings of a specialized course organized by the CERN Accelerator School (CAS).The topic this time being ’Intensity Limitations in Particle Beams’. The course was held at CERN, Switzerland,from 2-11 November 2015. The last course on this topic was organized in the framework of the Joint US-CERNSchool on Particle Accelerators in November 1990. It was felt that the progress in the field justified a revisedcourse. The lectures addressed fundamental theory as well as experimental results. The indispensable beamdiagnostics and mitigation measures were covered in dedicated lectures. The lectures were complemented byseveral sessions of exercises and the discussion of the solutions.

  8. Linear particle accelerator with seal structure between electrodes and insulators

    Science.gov (United States)

    Broadhurst, John H.

    1989-01-01

    An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.

  9. Reliability Approach for Machine Protection Design in Particle Accelerators

    CERN Document Server

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

    2013-01-01

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

  10. Measurements and Simulations of Impedance Reduction Techniques in Particle Accelerators

    CERN Document Server

    Day, Hugo Alistair; Jones, Roger

    Wakefields and the corresponding frequency-domain phenomenon beam coupling impedance have been well studied for a number of years as a source of beam instabilities within particle accelerators. With the development of the Large Hadron Collider (LHC) and the large beam currents stored in the LHC during fills for physics production, wakefield driven instabilities and strong beam induced heating have become a limiting factors in luminosity production due to both instantaneous luminousity and the available time for collisions.\

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

    CERN Multimedia

    2014-01-01

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

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

    CERN Multimedia

    HR Department

    2010-01-01

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

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

    CERN Multimedia

    HR Department

    2010-01-01

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

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

    CERN Multimedia

    HR Department

    2008-01-01

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

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

    CERN Multimedia

    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...

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

    CERN Multimedia

    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...

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

    CERN Multimedia

    Monique Duval

    2005-01-01

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

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

    CERN Multimedia

    Monique Duval

    2005-01-01

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

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

    CERN Multimedia

    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 ...

  20. Stochastic particle acceleration at parallel astrophysical shock waves

    Science.gov (United States)

    Schlickeiser, R.; Campeanu, A.; Lerche, L.

    1993-09-01

    We present exact analytical solutions to the full cosmic ray transport equation describing the diffusive acceleration of cosmic ray protons at parallel nonrelativistic shock waves including momentum diffusion in the downstream region of the shock. The downstream region is of finite extent to avoid the unphysical situation of background waves acting as an infinite source of energy. The spatial diffusion coefficient of particles is assumed to be independent of particle energy. The solutions allow for (i) any momentum dependence of the particle injection at the shock, (ii) any spatial dependence of the upstream spatial diffusion coefficient, and (iii) any spatial dependence of the downstream spatial diffusion coefficient. We assume that the incoming waves upstream are right- and left-handed circularly polarised backward moving Alfvén waves, as suggested by the streaming instability of the upstream precursor cosmic ray distribution. Interaction of these waves with the fast super-Alfvénic adiabatic shock makes momentum diffusion in the downstream region unavoidable. The downstream solution is an infinite sum of power laws whose spectral indices follow from a transcendental eigenvalue equation. Each individual power law component is weighted by expansion coefficients that depend on the actual downstream position. Quite generally the shape of the downstream distribution function is concavely curved, but approaches a single power law at large momenta. In the formal limit of vanishing momentum diffusion and infinite extent of the downstream region our general solution approaches the classical result of Axford et al. (1977), Krymsky (1977), Bell (1978), and Blandford & Ostriker (1978). For efficient momentum diffusion of particles in the downstream region of the shock, the particle spectra become flatter than in the original treatment of diffusive shock acceleration, thereby removing some of the noted discrepancies of the original theory with the explanation of fiat

  1. Linear accelerator accelerating module to suppress back-acceleration of field-emitted particles

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Stephen V.; Marhauser, Frank; Douglas, David R.; Ament, Lucas J. P.

    2017-12-05

    A method for the suppression of upstream-directed field emission in RF accelerators. The method is not restricted to a certain number of cavity cells, but requires similar operating field levels in all cavities to efficiently annihilate the once accumulated energy. Such a field balance is desirable to minimize dynamic RF losses, but not necessarily achievable in reality depending on individual cavity performance, such as early Q.sub.0-drop or quench field. The method enables a significant energy reduction for upstream-directed electrons within a relatively short distance. As a result of the suppression of upstream-directed field emission, electrons will impact surfaces at rather low energies leading to reduction of dark current and less issues with heating and damage of accelerator components as well as radiation levels including neutron generation and thus radio-activation.

  2. 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

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

    CERN Multimedia

    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...

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

    CERN Document Server

    Vollinger, C; Jensen, E

    2014-01-01

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

  5. Particle acceleration and exotic light emission in structured plasma wakefields

    Science.gov (United States)

    Vieira, Jorge

    2017-10-01

    Twisted Laguerre Gaussian lasers, with orbital angular momentum (OAM), are characterised by twisted wavefronts and doughnut intensity profiles. These lasers provide a transformative set of research directions in a growing range of fields, particularly at intensities below damage thresholds. Here, we explore how the interaction between ultra-intense twisted light and matter could enhance plasma accelerators and light sources. We support our findings with theory and massively parallel three-dimensional particle-in-cell Osiris simulations. Providing a solution to a long-lasting challenge in plasma acceleration, we show that twisted light can excite a nonlinear doughnut blowout suitable for electron and positron focusing and acceleration. This is a new type of wakefield that contrasts with the nonlinear spherical blowout, characterised by positron defocusing forces. Despite being driven by an OAM laser, doughnut plasma waves contain no OAM. This picture changes dramatically, when the laser driver contain multiple OAM levels characterised by distinct frequencies. The corresponding beating pattern results in a spiralling laser intensity profile, known as a light spring, which can excite a twisted plasma wave with OAM. The twisted wakefields accelerate particles both longitudinally and azimuthally. This feature can be exploited towards the generation of relativistic bunches with similar longitudinal and transverse momenta, which changes radiation emission processes. Structured lasers have been produced in the laboratory, using conventional spiral phase plates and plasma based holograms. Here, we demonstrate how to create and amplify ultra-intense OAM lasers in the plasma, through stimulated Raman backscattering. Work supported by FCT (Portugal) Grant No. SFRH/IF/01635/2015.

  6. 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.

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

    OpenAIRE

    Nürnberg, Frank

    2010-01-01

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

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

    Science.gov (United States)

    McWilliams, Sean T

    2013-01-04

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

  9. Collisionless shocks in space plasmas structure and accelerated particles

    CERN Document Server

    Burgess, David

    2015-01-01

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

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

    CERN Document Server

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

    2015-01-01

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

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

    CERN Document Server

    Fjellstrom, Mattias; Hansson, Johan

    2013-12-13

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

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

    CERN Document Server

    Kasprowicz, Grzegorz

    2010-01-01

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

  13. Proceedings of B Factories, the state of the art in accelerators, detectors and physics

    Energy Technology Data Exchange (ETDEWEB)

    Hitlin, D. (ed.) (California Inst. of Tech., Pasadena, CA (United States))

    1992-11-01

    The conference B Factories, The State of the Art in Accelerators, Detectors and Physics was held at Stanford Linear Accelerator Center on April 6-10, 1992. The guiding principle of the conference was to bring together accelerator physicists and high energy experimentalists and theorists at the same time, with the goal of encouraging communication in defining and solving problems in a way which cut across narrow areas of specialization. Thus the conference was, in large measure, two distinct conferences, one involving accelerator specialists, the other theorists and experimentalists. There were initial and closing plenary sessions, and three separate tracks of parallel sessions, called Accelerator, Detector/Physics and Joint Interest sessions. This report contains the papers of this conference, the general topics of these cover: vacuum system, lattice design, beam-beam interactions, rf systems, feedback systems, measuring instrumentation, the interaction region, radiation background, particle detectors, particle tracking and identification, data acquisition, and computing system, and particle theory.

  14. Feature-Based Analysis of Plasma-Based Particle Acceleration Data

    Energy Technology Data Exchange (ETDEWEB)

    Rubel, Oliver [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Geddes, Cameron G. R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chen, Min [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cormier-Michel, Estelle [Tech-X Corp., Boulder, CO (United States); Bethel, E. Wes [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-02-01

    Plasma-based particle accelerators can produce and sustain thousands of times stronger acceleration fields than conventional particle accelerators, providing a potential solution to the problem of the growing size and cost of conventional particle accelerators. To facilitate scientific knowledge discovery from the ever growing collections of accelerator simulation data generated by accelerator physicists to investigate next-generation plasma-based particle accelerator designs, we describe a novel approach for automatic detection and classification of particle beams and beam substructures due to temporal differences in the acceleration process, here called acceleration features. The automatic feature detection in combination with a novel visualization tool for fast, intuitive, query-based exploration of acceleration features enables an effective top-down data exploration process, starting from a high-level, feature-based view down to the level of individual particles. We describe the application of our analysis in practice to analyze simulations of single pulse and dual and triple colliding pulse accelerator designs, and to study the formation and evolution of particle beams, to compare substructures of a beam and to investigate transverse particle loss.

  15. Hollow-core photonic band gap fibers for particle acceleration

    Directory of Open Access Journals (Sweden)

    Robert J. Noble

    2011-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-19

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

  17. Particle Acceleration in Cosmic Sites - Astrophysics Issues in our Understanding of Cosmic Rays

    OpenAIRE

    Diehl, R. L.

    2009-01-01

    Laboratory experiments to explore plasma conditions and stimulated particle acceleration can illuminate aspects of the cosmic particle acceleration process. Here we discuss the cosmic-ray candidate source object variety, and what has been learned about their particle-acceleration characteristics. We identify open issues as discussed among astrophysicists. -- The cosmic ray differential intensity spectrum is a rather smooth power-law spectrum, with two kinks at the "knee" (~10^15 eV) and at th...

  18. submitter Introduction to Collective Effects in Particle Accelerators

    CERN Document Server

    Zimmermann, Frank

    2016-01-01

    The beam intensity and the beam brightness of particle accelerators or colliders operated for high - energy physics were, and are, often severely limited by “collective effects” (e.g.[1]). By contrast, new light sources, such as linac - based free electron lasers, may even rely on collective instabilities to accomplish their mission! The term “collective effects” refers to the interaction of beam particles with each other through a variety of processes, e.g. (1) non-delayed self-fields and image fields present even for constant perfectly conducting and magnetic boundaries (direct and indirect “space - charge effects”), (2) longer - lived electro-magnetic “wake fields” due to a finite chamber resistivity or geometric variation in the beam - pipe cross section, which typically affect later parts of the beam, (3) coherent synchrotron radiation, which on a curved trajectory may even influence earlier parts of the beam, giving rise to “non-causal” wake fields, otherwise not normally encountered...

  19. On magnetic field amplification and particle acceleration near non-relativistic astrophysical shocks: particles in MHD cells simulations

    Science.gov (United States)

    van Marle, Allard Jan; Casse, Fabien; Marcowith, Alexandre

    2018-01-01

    We present simulations of magnetized astrophysical shocks taking into account the interplay between the thermal plasma of the shock and suprathermal particles. Such interaction is depicted by combining a grid-based magnetohydrodynamics description of the thermal fluid with particle in cell techniques devoted to the dynamics of suprathermal particles. This approach, which incorporates the use of adaptive mesh refinement features, is potentially a key to simulate astrophysical systems on spatial scales that are beyond the reach of pure particle-in-cell simulations. We consider in this study non-relativistic shocks with various Alfvénic Mach numbers and magnetic field obliquity. We recover all the features of both magnetic field amplification and particle acceleration from previous studies when the magnetic field is parallel to the normal to the shock. In contrast with previous particle-in-cell-hybrid simulations, we find that particle acceleration and magnetic field amplification also occur when the magnetic field is oblique to the normal to the shock but on larger time-scales than in the parallel case. We show that in our simulations, the suprathermal particles are experiencing acceleration thanks to a pre-heating process of the particle similar to a shock drift acceleration leading to the corrugation of the shock front. Such oscillations of the shock front and the magnetic field locally help the particles to enter the upstream region and to initiate a non-resonant streaming instability and finally to induce diffuse particle acceleration.

  20. Laser-accelerated proton beams as a new particle source

    Energy Technology Data Exchange (ETDEWEB)

    Nuernberg, Frank

    2010-11-15

    The framework of this thesis is the investigation of the generation of proton beams using high-intensity laser pulses. In this work, an experimental method to fully reconstruct laser-accelerated proton beam parameters, called radiochromic film imaging spectroscopy (RIS), was developed. Since the proton beam expansion is a plasma expansion with accompanying electrons, a low-energy electron spectrometer was developed, built and tested to study the electron distribution matching to the proton beam energy distribution. Two experiments were carried out at the VULCAN Petawatt laser with the aim of showing dynamic control and enhancement of proton acceleration using multiple or defocused laser pulses. Irradiating the target with a long pulse, low-intensity laser (10{sup 12} W/cm{sup 2}) prior to the main pulse ({proportional_to}ns), an optimum pre-plasma density scale length of 60 {mu}m is generated leading to an enhancement of the maximum proton energy ({proportional_to}25%), the proton flux (factor of 3) and the beam uniformity. Proton beams were generated more efficiently than previously by driving thinner target foils at a lower intensity over a large area. The optimum condition was a 2 {mu}m foil irradiated with an intensity of 10{sup 19} W/cm{sup 2} onto a 60 {mu}m spot. Laser to proton beam efficiencies of 7.8% have been achieved (2.2% before) - one of the highest conversion efficiencies ever achieved. In the frame of this work, two separate experiments at the TRIDENT laser system have shown that these laser-accelerated proton beams, with their high number of particles in a short pulse duration, are well-suited for creating isochorically heated matter in extreme conditions. Besides the manipulation of the proton beam parameters directly during the generation, the primary aim of this thesis was the capture, control and transport of laser-accelerated proton beams by a solenoidal magnetic field lense for further purpose. In a joint project proposal, the laser and

  1. Experimental particle acceleration by water evaporation induced by shock waves

    Science.gov (United States)

    Scolamacchia, T.; Alatorre Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Cimarelli, C.

    2010-12-01

    Shock waves are commonly generated during volcanic eruptions. They induce sudden changes in pressure and temperature causing phase changes. Nevertheless, their effects on flowfield properties are not well understood. Here we investigate the role of gas expansion generated by shock wave propagation in the acceleration of ash particles. We used a shock tube facility consisting of a high-pressure (HP) steel autoclave (450 mm long, 28 mm in internal diameter), pressurized with Ar gas, and a low-pressure tank at atmospheric conditions (LP). A copper diaphragm separated the HP autoclave from a 180 mm tube (PVC or acrylic glass) at ambient P, with the same internal diameter of the HP reservoir. Around the tube, a 30 cm-high acrylic glass cylinder, with the same section of the LP tank (40 cm), allowed the observation of the processes occurring downstream from the nozzle throat, and was large enough to act as an unconfined volume in which the initial diffracting shock and gas jet expand. All experiments were performed at Pres/Pamb ratios of 150:1. Two ambient conditions were used: dry air and air saturated with steam. Carbon fibers and glass spheres in a size range between 150 and 210 μm, were placed on a metal wire at the exit of the PVC tube. The sudden decompression of the Ar gas, due to the failure of the diaphragm, generated an initial air shock wave. A high-speed camera recorded the processes between the first 100 μsec and several ms after the diaphragm failure at frame rates ranging between 30,000 and 50,000 fps. In the experiments with ambient air saturated with steam, the high-speed camera allowed to visualize the condensation front associated with the initial air shock; a maximum velocity of 788 m/s was recorded, which decreases to 524 m/s at distance of 0.5 ±0.2 cm, 1.1 ms after the diaphragm rupture. The condensation front preceded the Ar jet front exhausting from the reservoir, by 0.2-0.5 ms. In all experiments particles velocities following the initial

  2. Particle-in-Cell Codes for plasma-based particle acceleration

    CERN Document Server

    Pukhov, Alexander

    2016-01-01

    Basic principles of particle-in-cell (PIC ) codes with the main application for plasma-based acceleration are discussed. The ab initio full electromagnetic relativistic PIC codes provide the most reliable description of plasmas. Their properties are considered in detail. Representing the most fundamental model, the full PIC codes are computationally expensive. The plasma-based acceler- ation is a multi-scale problem with very disparate scales. The smallest scale is the laser or plasma wavelength (from one to hundred microns) and the largest scale is the acceleration distance (from a few centimeters to meters or even kilometers). The Lorentz-boost technique allows to reduce the scale disparity at the costs of complicating the simulations and causing unphysical numerical instabilities in the code. Another possibility is to use the quasi-static approxi- mation where the disparate scales are separated analytically.

  3. Laser source of neutral atoms for collective field particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Bykovskiy, Yu.A.; Mironov, V.E.; Sarantsev, V.P.; Sil' nov, S.M.; Sotnichenko, E.A.; Ter-Martirosyan, Z.A.; Shestakov, B.A.

    1984-03-01

    Laser sources for collective-field particle accelerators, of ions of almost all chemical elements, operate in deep vacuum (10/sup -8/ -10/sup -9/ torr) and in a strong alternating magnetic field (up to 20 kOe, 50 Hz). Under such conditions a laser source is required to deliver an atom flux of 10/sup 11/ -10/sup 12/ in pulses of 10-100 ms duration from a target to electron rings. Such a laser source has been designed for the collective-field heavy-ion accelerator at the Joint Institute of Nuclear Research. It consists of a laser, focusing lens, and conical target of the material whose atoms are to be extracted. The equipment is laid out with the compressor tube mounted on a support inside the vacuum chamber and the laser source in front of the window on the extension of the compressor tube axis. This construction can be modified for large electron rings, with axicon optics that reshape the incoming laser beam into an annular beam for electron rings with radii longer than 8 cm or by moving the laser source from the axial location to a peripheral location relative to the compressor tube for electron rings with radii of 30-35 cm. These three variants of such a laser source were evaluated in an experimental test stand, with a Q-switched YAG:Nd/sup 3 +/ laser (wavelength lambda = 1.06 ..mu..m) emitting radiation pulses of 0.06 J energy and 10 ns duration, and with lead, aluminum, iron, or copper used as target material. The results of measurements, accurate within 20%, indicate that the laser source is most effective with lead targets and least effective with copper targets. 9 references, 9 figures.

  4. Acceleration of inertial particles in wall bounded flows: DNS and LES with stochastic modelling of the subgrid acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Zamansky, Remi; Vinkovic, Ivana; Gorokhovski, Mikhael, E-mail: ivana.vinkovic@univ-lyonl.fr [Laboratoire de Mecanique des Fluides et d' Acoustique CNRS UMR 5509 Ecole Centrale de Lyon, 36, av. Guy de Collongue, 69134 Ecully Cedex (France)

    2011-12-22

    Inertial particle acceleration statistics are analyzed using DNS for turbulent channel flow. Along with effects recognized in homogeneous isotropic turbulence, an additional effect is observed due to high and low speed vortical structures aligned with the channel wall. In response to those structures, particles with moderate inertia experience strong longitudinal acceleration variations. DNS is also used in order to assess LES-SSAM (Subgrid Stochastic Acceleration Model), in which an approximation to the instantaneous non-filtered velocity field is given by simulation of both, filtered and residual, accelerations. This approach allow to have access to the intermittency of the flow at subgrid scale. Advantages of LES-SSAM in predicting particle dynamics in the channel flow at a high Reynolds number are shown.

  5. Particle Acceleration during Magnetic Reconnection in a Low-beta Plasma

    Science.gov (United States)

    Li, Xiaocan; Guo, Fan; Li, Hui; Li, Gang

    2017-07-01

    Magnetic reconnection is a primary mechanism for particle energization in space and astrophysical plasmas. By carrying out two-dimensional (2D) fully kinetic simulations, we study particle acceleration during magnetic reconnection in plasmas with different plasma β (the ratio between the thermal pressure and the magnetic pressure). For the high-β cases, we do not observe significant particle acceleration. In the low-β regime (β accelerated particles integrated over the whole simulation box appears highly non-thermal, it is actually the superposition of a series of distributions in different sectors of a 2D magnetic island. Each of those distributions has only a small non-thermal component compared with its thermal core. By tracking a large number of particles, we show that particles get energized in X-line regions, contracting magnetic islands, and magnetic island coalescence regions. We obtain the particle energization rate {\\boldsymbol{j}}\\cdot {\\boldsymbol{E}} by averaging over particle drift motions and find that it agrees well with the particle kinetic energy change. We quantify the contribution of curvature drift, gradient drift, polarization drift, magnetization, non-gyrotropic effect, and parallel electric field in different acceleration regions. We find that the major energization is due to particle curvature drift along the motional electric field. The other particle motions contribute less but may become important in different acceleration regions. The highly efficient particle energization in low-β plasmas may help us understand the strong particle energization in solar flares and accretion disk coronae.

  6. Variation in Angular Velocity and Angular Acceleration of a Particle in Rectilinear Motion

    Science.gov (United States)

    Mashood, K. K.; Singh, V. A.

    2012-01-01

    We discuss the angular velocity ([image omitted]) and angular acceleration ([image omitted]) associated with a particle in rectilinear motion with constant acceleration. The discussion was motivated by an observation that students and even teachers have difficulty in ascribing rotational motion concepts to a particle when the trajectory is a…

  7. Advance in Vertical Buffered Electropolishing on Niobium for Particle Accelerators*

    Energy Technology Data Exchange (ETDEWEB)

    A.T. Wu, S. Jin, J.D. Mammosser, C.E. Reece, R.A. Rimmer,L. Lin, X.Y. Lu, K. Zhao

    2011-09-01

    Niobium (Nb) is the most popular material that has been employed for making superconducting radio frequency (SRF) cavities to be used in various particle accelerators over the last couple of decades. One of the most important steps in fabricating Nb SRF cavities is the final chemical removal of 150 {mu}m of Nb from the inner surfaces of the SRF cavities. This is usually done by either buffered chemical polishing (BCP) or electropolishing (EP). Recently a new Nb surface treatment technique called buffered electropolishing (BEP) has been developed at Jefferson Lab. It has been demonstrated that BEP can produce the smoothest surface finish on Nb ever reported in the literature while realizing a Nb removal rate as high as 10 {mu}m/min that is more than 25 and 5 times quicker than those of EP and BCP(112) respectively. In this contribution, recent advance in optimizing and understanding BEP treatment technique is reviewed. Latest results from RF measurements on BEP treated Nb single cell cavities by our unique vertical polishing system will be reported.

  8. DC-like Phase Space Manipulation and Particle Acceleration Using Chirped AC Fields

    Energy Technology Data Exchange (ETDEWEB)

    P.F. Schmit and N.J. Fisch

    2009-06-17

    Waves in plasmas can accelerate particles that are resonant with the wave. A DC electric field also accelerates particles, but without a resonance discrimination, which makes the acceleration mechanism profoundly different. We investigate the effect on a Hamiltonian distribution of an accelerating potential waveform, which could, for example, represent the average ponderomotive effect of two counterpropagating electromagnetic waves. In particular, we examine the apparent DC-like time-asymptotic response of the distribution in regimes where the potential structure is accelerated adiabatically. A highly resonant population within the distribution is always present, and we characterize its nonadiabatic response during wave-particle resonance using an integral method in the noninertial reference frame moving with the wave. Finally, we show that in the limit of infinitely slow acceleration of the wave, these highly resonant particles disappear and the response

  9. Planning the Future of U.S. Particle Physics (Snowmass 2013): Chapter 6: Accelerator Capabilities

    CERN Document Server

    Barletta, W.A.; Battaglia, M.; Bruning, O.; Byrd, J.; Ent, R.; Flanagan, J.; Gai, W.; Galambos, J.; Hoffstaetter, G.; Hogan, M.; Klute, M.; Nagaitsev, S.; Palmer, M.; Prestemon, S.; Roser, T.; Rossi, L.; Shiltsev, V.; Varner, G.; Yokoya, K.

    2014-01-01

    These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 6, on Accelerator Capabilities, discusses the future progress of accelerator technology, including issues for high-energy hadron and lepton colliders, high-intensity beams, electron-ion colliders, and necessary R&D for future accelerator technologies.

  10. Oxidation states of uranium in depleted uranium particles from Kuwait.

    Science.gov (United States)

    Salbu, B; Janssens, K; Lind, O C; Proost, K; Gijsels, L; Danesi, P R

    2005-01-01

    The oxidation states of uranium in depleted uranium (DU) particles were determined by synchrotron radiation based mu-XANES, applied to individual particles isolated from selected samples collected at different sites in Kuwait. Based on scanning electron microscopy with X-ray microanalysis prior to mu-XANES, DU particles ranging from submicrons to several hundred micrometers were observed. The median particle size depended on sources and sampling sites; small-sized particles (median 13 microm) were identified in swipes taken from the inside of DU penetrators holes in tanks and in sandy soil collected below DU penetrators, while larger particles (median 44 microm) were associated with fire in a DU ammunition storage facility. Furthermore, the (236)U/(235)U ratios obtained from accelerator mass spectrometry demonstrated that uranium in the DU particles originated from reprocessed fuel (about 10(-2) in DU from the ammunition facility, about 10(-3) for DU in swipes). Compared to well-defined standards, all investigated DU particles were oxidized. Uranium particles collected from swipes were characterized as UO(2), U(3)O(8) or a mixture of these oxidized forms, similar to that observed in DU affected areas in Kosovo. Uranium particles formed during fire in the DU ammunition facility were, however, present as oxidation state +5 and +6, with XANES spectra similar to solid uranyl standards. Environmental or health impact assessments for areas affected by DU munitions should therefore take into account the presence of respiratory UO(2), U(3)O(8) and even UO(3) particles, their corresponding weathering rates and the subsequent mobilisation of U from oxidized DU particles.

  11. Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, C. B.; Esarey, E.; Benedetti, C.; Toth, Cs.; Geddes, C. G. R.; Leemans, W.P.

    2010-06-01

    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.

  12. On the performance of accelerated particle swarm optimization for charging plug-in hybrid electric vehicles

    Directory of Open Access Journals (Sweden)

    Imran Rahman

    2016-03-01

    Full Text Available Transportation electrification has undergone major changes since the last decade. Success of smart grid with renewable energy integration solely depends upon the large-scale penetration of plug-in hybrid electric vehicles (PHEVs for a sustainable and carbon-free transportation sector. One of the key performance indicators in hybrid electric vehicle is the State-of-Charge (SoC which needs to be optimized for the betterment of charging infrastructure using stochastic computational methods. In this paper, a newly emerged Accelerated particle swarm optimization (APSO technique was applied and compared with standard particle swarm optimization (PSO considering charging time and battery capacity. Simulation results obtained for maximizing the highly nonlinear objective function indicate that APSO achieves some improvements in terms of best fitness and computation time.

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

    CERN Document Server

    Edgecock, Rob

    2013-01-01

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

  14. Reconnection and particle acceleration in interacting flux ropes - II. 3D effects on test particles in magnetically dominated plasmas

    Science.gov (United States)

    Ripperda, B.; Porth, O.; Xia, C.; Keppens, R.

    2017-11-01

    We analyse particle acceleration in explosive reconnection events in magnetically dominated proton-electron plasmas. Reconnection is driven by large-scale magnetic stresses in interacting current-carrying flux tubes. Our model relies on development of current-driven instabilities on macroscopic scales. These tilt-kink instabilities develop in an initially force-free equilibrium of repelling current channels. Using magnetohydrodynamics (MHD) methods we study a 3D model of repelling and interacting flux tubes in which we simultaneously evolve test particles, guided by electromagnetic fields obtained from MHD. We identify two stages of particle acceleration; initially particles accelerate in the current channels, after which the flux ropes start tilting and kinking and particles accelerate due to reconnection processes in the plasma. The explosive stage of reconnection produces non-thermal energy distributions with slopes that depend on plasma resistivity and the initial particle velocity. We also discuss the influence of the length of the flux ropes on particle acceleration and energy distributions. This study extends previous 2.5D results to 3D setups, providing all ingredients needed to model realistic scenarios like solar flares, black hole flares and particle acceleration in pulsar wind nebulae: formation of strong resistive electric fields, explosive reconnection and non-thermal particle distributions. By assuming initial energy equipartition between electrons and protons, applying low resistivity in accordance with solar corona conditions and limiting the flux rope length to a fraction of a solar radius, we obtain realistic energy distributions for solar flares with non-thermal power-law tails and maximum electron energies up to 11 MeV and maximum proton energies up to 1 GeV.

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

    CERN Document Server

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

    2014-01-01

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

  16. The acceleration of solid particles subjected to cavitation nucleation

    DEFF Research Database (Denmark)

    Borkent, B.M.; Arora, M.; Ohl, C.-D.

    2008-01-01

    The cavity -particle dynamics at cavitation inception on the surface of spherical particles suspended in water and exposed to a strong tensile stress wave is experimentally studied with high-speed photography. Particles, which serve as nucleation sites for cavitation bubbles, are set into a fast...

  17. Particle physicist's dreams about PetaelectronVolt laser plasma accelerators

    Science.gov (United States)

    Vesztergombi, G.

    2012-07-01

    Present day accelerators are working well in the multi TeV energy scale and one is expecting exciting results in the coming years. Conventional technologies, however, can offer only incremental (factor 2 or 3) increase in beam energies which does not follow the usual speed of progress in the frontiers of high energy physics. Laser plasma accelerators theoretically provide unique possibilities to achieve orders of magnitude increases entering the PetaelectronVolt (PeV) energy range. It will be discussed what kind of new perspectives could be opened for the physics at this new energy scale. What type of accelerators would be required?.

  18. Stochastic particle acceleration at shocks in the presence of braided magnetic fields

    OpenAIRE

    Kirk, J. G.; Duffy, P.; Gallant, Y. A.

    1996-01-01

    The theory of diffusive acceleration of energetic particles at shock fronts assumes charged particles undergo spatial diffusion in a uniform magnetic field. If, however, the magnetic field is not uniform, but has a stochastic or braided structure, the transport of charged particles across the average direction of the field is more complicated. Assuming quasi-linear behaviour of the field lines, the particles undergo sub-diffusion on short time scales. We derive the propagator for such motion,...

  19. Accelerated Learning Options: A Promising Strategy for States. Policy Insights

    Science.gov (United States)

    Michelau, Demaree

    2006-01-01

    This issue of Policy Insights draws on findings from WICHE's report Accelerated Learning Options: Moving the Needle on Access and Success, to lay out some of the important policy issues that decision makers might consider when adopting new state policy related to accelerated learning or modifying policies already in existence. The publication…

  20. Accelerator mass spectrometry: state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator Mass Spectrometry (AMS) is the analytical technique of choice for the detection of long-lived radionuclides which cannot be practically analysed with decay counting or conventional mass spectrometry. The main use of AMS has been in the analysis of radiocarbon and other cosmogenic radionuclides for archaeological, geological and environmental applications. In addition, AMS has been recently applied in biomedicine to study exposure of human tissues to chemicals and biomolecules at attomole levels. There is also a world-wide effort to analyse rare nuclides of heavier masses, such as long-lived actinides, with important applications in safeguards and nuclear waste disposal. The use of AMS is limited by the expensive accelerator technology required and there are several attempts to develop smaller and cheaper AMS spectrometers. 5 refs.

  1. Magnetohydrodynamic Simulations of Reconnection and Particle Acceleration: Three-Dimensional Effects

    OpenAIRE

    Kowal, Grzegorz; Pino, E. M. de Gouveia Dal; Lazarian, A.

    2011-01-01

    The magnetic fields can change their topology through a process known as magnetic reconnection. This process in not only important for understanding the origin and evolution of the large-scale magnetic field, but is seen as a possibly efficient particle accelerator producing cosmic rays mainly through the first order Fermi process. In this work we study the properties of particle acceleration in reconnection zones and show that the velocity component parallel to the magnetic field of test par...

  2. APT related papers presented at the 1997 particle accelerator conference, Vancouver, May 12--16, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, G. [comp.

    1997-07-01

    Tritium is essential for the US nuclear weapons to function, but because it is radioactive with a half-life of 12.3 years, the supply must be periodically replenished. Presently, only reactor or accelerator systems can be used to produce tritium. This report is a compilation of 31 papers given at the 1997 Particle Accelerator Conference which dealt with the accelerator production of tritium. The papers are grouped into two categories, invited and contributed.

  3. Fermilab and Berkeley Lab Collaborate with Meyer Tool on Key Component for European Particle Accelerator

    CERN Multimedia

    2004-01-01

    Officials of the U.S. Department of Energy's Fermi National Accelerator Laboratory and Lawrence Berkeley National Laboratory announced yesterday the completion of a key component of the U.S. contribution to the Large Hadron Collider, a particle accelerator under construction at CERN, in Geneva, Switzerland

  4. Thermal fatigue issues in high-gradient particle accelerators

    CERN Document Server

    Heikkinen, Samuli Tapio; Neupert, Holger

    2006-01-01

    The CLIC (Compact LInear Collider) is being studied at CERN (European Organization for Nuclear Research) as a possible future high-energy (0.5-5 TeV centre-of-mass) physics facility. The current aim of the CLIC Study Team is to demonstrate the key feasibility issues before 2010. CLIC will be about 33 kilometers long and will be buried 100 meters underground. The main linac of CLIC consists of accelerating structures with the following demanding performance requirements: accelerating gradients of about 150 MV/m, power flows of about 200 MW, 1-2 ìm dimensional tolerances, an optical-quality surface finish and ultimately a low mass production cost. About 80% of CLIC's 33 kilometer length will be filled with main beam accelerating structures, which will require of the order of ten thousand tons of raw material and millions of individual parts. One of the main limiting factors of the main linac accelerating structures is the thermal fatigue due to the pulsed surface heating. The accelerating RFpower pulses heat u...

  5. Momentum-dependent diffusive particle acceleration in modified shock fronts. [for galactic cosmic rays

    Science.gov (United States)

    Webb, G. M.; Bogdan, T. J.; Lee, M. A.; Lerche, I.

    1985-01-01

    In the presently derived analytic solutions of the steady transport equation for diffusive particle acceleration in a modified, planar shock front having free escape boundaries, the fluid velocity profile through the shock transition decreases monotonically between the upstream and downstream boundaries. The spatial diffusion coefficient's spatial dependence is linked to that of the fluid velocity profile. Attention is given to the solution corresponding to monoenergetic particle injection at the shock front, with free particle escape at finite distances both upstream and downstream of the shock. The accelerated particle spectrum is dominated at high energies by an exponential cutoff, due to the competition between acceleration by the first-order Fermi mechanism and particle loss through the free escape boundaries.

  6. On magnetic field amplification and particle acceleration near non-relativistic collisionless shocks: Particles in MHD Cells simulations

    Science.gov (United States)

    Casse, F.; van Marle, A. J.; Marcowith, A.

    2018-01-01

    We present simulations of magnetized astrophysical shocks taking into account the interplay between the thermal plasma of the shock and supra-thermal particles. Such interaction is depicted by combining a grid-based magneto-hydrodynamics description of the thermal fluid with particle-in-cell techniques devoted to the dynamics of supra-thermal particles. This approach, which incorporates the use of adaptive mesh refinement features, is potentially a key to simulate astrophysical systems on spatial scales that are beyond the reach of pure particle-in-cell simulations. We consider non-relativistic super-Alfénic shocks with various magnetic field obliquity. We recover all the features from previous studies when the magnetic field is parallel to the normal to the shock. In contrast with previous particle-in-cell and hybrid simulations, we find that particle acceleration and magnetic field amplification also occur when the magnetic field is oblique to the normal to the shock but on larger timescales than in the parallel case. We show that in our oblique shock simulations the streaming of supra-thermal particles induces a corrugation of the shock front. Such oscillations of both the shock front and the magnetic field then locally helps the particles to enter the upstream region and to initiate a non-resonant streaming instability and finally to induce diffuse particle acceleration.

  7. Observational Signatures of Particle Acceleration in Supernova Remnants

    NARCIS (Netherlands)

    Helder, E.A.; Vink, J.; Bykov, A.M.; Ohira, Y.; Raymond, J.C.; Terrier, R.

    2012-01-01

    We evaluate the current status of supernova remnants as the sources of Galactic cosmic rays. We summarize observations of supernova remnants, covering the whole electromagnetic spectrum and describe what these observations tell us about the acceleration processes by high Mach number shock fronts. We

  8. Particle acceleration in tangential discontinuities by lower hybrid waves

    Directory of Open Access Journals (Sweden)

    D. Spicer

    2002-01-01

    Full Text Available We consider the role that the lower-hybrid wave turbulence plays in providing the necessary resistivity at collisionless reconnection sights. The mechanism for generating the waves is considered to be the lower-hybrid drift instability. We find that the level of the wave amplitude is sufficient enough to heat and accelerate both electrons and ions.

  9. Physics of the saturation of particle acceleration in relativistic magnetic reconnection

    Science.gov (United States)

    Kagan, Daniel; Nakar, Ehud; Piran, Tsvi

    2018-02-01

    We investigate the saturation of particle acceleration in relativistic reconnection using two-dimensional particle-in-cell simulations at various magnetizations σ. We find that the particle energy spectrum produced in reconnection quickly saturates as a hard power law that cuts off at γ ≈ 4σ, confirming previous work. Using particle tracing, we find that particle acceleration by the reconnection electric field in X-points determines the shape of the particle energy spectrum. By analyzing the current sheet structure, we show that physical cause of saturation is the spontaneous formation of secondary magnetic islands that can disrupt particle acceleration. By comparing the size of acceleration regions to the typical distance between disruptive islands, we show that the maximum Lorentz factor produced in reconnection is γ ≈ 5σ, which is very close to what we find in our particle energy spectra. We also show that the dynamic range in Lorentz factor of the power law spectrum in reconnection is ≤40. The hardness of the power law combined with its narrow dynamic range implies that relativistic reconnection is capable of producing the hard narrowband flares observed in the Crab Nebula but has difficulty producing the softer broadband prompt GRB emission.

  10. OpenFOAM Modeling of Particle Heating and Acceleration in Cold Spraying

    Science.gov (United States)

    Leitz, K.-H.; O'Sullivan, M.; Plankensteiner, A.; Kestler, H.; Sigl, L. S.

    2018-01-01

    In cold spraying, a powder material is accelerated and heated in the gas flow of a supersonic nozzle to velocities and temperatures that are sufficient to obtain cohesion of the particles to a substrate. The deposition efficiency of the particles is significantly determined by their velocity and temperature. Particle velocity correlates with the amount of kinetic energy that is converted to plastic deformation and thermal heating. The initial particle temperature significantly influences the mechanical properties of the particle. Velocity and temperature of the particles have nonlinear dependence on the pressure and temperature of the gas at the nozzle entrance. In this contribution, a simulation model based on the reactingParcelFoam solver of OpenFOAM is presented and applied for an analysis of particle velocity and temperature in the cold spray nozzle. The model combines a compressible description of the gas flow in the nozzle with a Lagrangian particle tracking. The predictions of the simulation model are verified based on an analytical description of the gas flow, the particle acceleration and heating in the nozzle. Based on experimental data, the drag model according to Plessis and Masliyah is identified to be best suited for OpenFOAM modeling particle heating and acceleration in cold spraying.

  11. OpenFOAM Modeling of Particle Heating and Acceleration in Cold Spraying

    Science.gov (United States)

    Leitz, K.-H.; O'Sullivan, M.; Plankensteiner, A.; Kestler, H.; Sigl, L. S.

    2017-09-01

    In cold spraying, a powder material is accelerated and heated in the gas flow of a supersonic nozzle to velocities and temperatures that are sufficient to obtain cohesion of the particles to a substrate. The deposition efficiency of the particles is significantly determined by their velocity and temperature. Particle velocity correlates with the amount of kinetic energy that is converted to plastic deformation and thermal heating. The initial particle temperature significantly influences the mechanical properties of the particle. Velocity and temperature of the particles have nonlinear dependence on the pressure and temperature of the gas at the nozzle entrance. In this contribution, a simulation model based on the reactingParcelFoam solver of OpenFOAM is presented and applied for an analysis of particle velocity and temperature in the cold spray nozzle. The model combines a compressible description of the gas flow in the nozzle with a Lagrangian particle tracking. The predictions of the simulation model are verified based on an analytical description of the gas flow, the particle acceleration and heating in the nozzle. Based on experimental data, the drag model according to Plessis and Masliyah is identified to be best suited for OpenFOAM modeling particle heating and acceleration in cold spraying.

  12. Design Concepts for RF-DC Conversion in Particle Accelerator Systems

    CERN Document Server

    Caspers, F; Grudiev, A; Sapotta, H

    2010-01-01

    In many particle accelerators considerable amounts of RF power reaching the megawatt level are converted into heat in dummy loads. After an overview of RF power in the range 200 MHz to 1 GHz dissipated at CERN we discuss several developments that have come up in the past using vacuum tube technology for RF-DC conversion. Amongst those the developments of the cyclotron wave converter CWC appears most suitable. With the availability of powerful Schottky diodes the solid state converter aspect has to be addressed as well. One of the biggest problems of Schottky diode based structures is the junction capacity. GaAs and GaN Schottky diodes show a significant reduction of this junction capacity as compared to silicon. Small rectenna type converter units which have been already developed for microwave powered helicopters can be used in waveguides or with coaxial power dividers.

  13. Micro-bubbles and micro-particles are not faithful tracers of turbulent acceleration

    CERN Document Server

    Mathai, Varghese; Brons, Jon; Sun, Chao; Lohse, Detlef

    2016-01-01

    We report on the Lagrangian statistics of acceleration of small (sub-Kolmogorov) bubbles and tracer particles with Stokes number St << 1 in turbulent flow. At decreasing Reynolds number, the bubble accelerations show deviations from that of tracer particles, i.e. they deviate from the Heisenberg-Yaglom prediction and show a quicker decorrelation despite their small size and minute St. Using direct numerical simulations, we show that these effects arise due the drift of these particles through the turbulent flow. We theoretically predict this gravity-driven effect for developed isotropic turbulence, with the ratio of Stokes to Froude number or equivalently the particle drift-velocity governing the enhancement of acceleration variance and the reductions in correlation time and intermittency. Our predictions are in good agreement with experimental and numerical results. The present findings are relevant to a range of scenarios encompassing tiny bubbles and droplets that drift through the turbulent oceans a...

  14. A report on the possible benefits of using high-temperature superconductor materials in particle accelerator design

    Science.gov (United States)

    Cohen, Leslie; Collins, Robert; Balko, Bohdan

    1988-12-01

    This report discusses different design concepts for particle beam accelerators. It demonstrates that with the use of high temperature superconducting materials, a more compact, lighter, and more robust accelerator design can be realized for the space based Neutral Particle Beam (NPB) accelerator.

  15. Harmonic states for the free particle

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, J [Departamento de Matematica Aplicada, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Lopez-Ruiz, F F; Aldaya, V; Cossio, F, E-mail: juguerre@um.es, E-mail: flopez@iaa.es, E-mail: valdaya@iaa.es, E-mail: focossiop@gmail.com [Instituto de Astrofisica de Andalucia, CSIC, Apartado Postal 3004, 18080 Granada (Spain)

    2011-11-04

    Different families of states, which are solutions of the time-dependent free Schroedinger equation, are imported from the harmonic oscillator using the quantum Arnold transformation introduced in Aldaya et al (2011 J. Phys. A: Math. Theor.44 065302). Among them, infinite series of states are given that are normalizable, expand the whole space of solutions, are spatially multi-localized and are eigenstates of a suitably defined number operator. Associated with these states new sets of coherent and squeezed states for the free particle are defined representing traveling, squeezed, multi-localized wave packets. These states are also constructed in higher dimensions, leading to the quantum mechanical version of the Hermite-Gauss and Laguerre-Gauss states of paraxial wave optics. Some applications of these new families of states and procedures to experimentally realize and manipulate them are outlined. (paper)

  16. Detection of accelerated particles from pulsed plasma discharge ...

    Indian Academy of Sciences (India)

    - ing). Consequently, more particles take energy from the wave field and the wave is damped. According to CCZ model, it is possible to estimate the total number of tracks. (ions) of an individual microbeam. For instance, figure 8 shows a photo ...

  17. AEi systems designing power sstem for world's largest particle accelerator

    CERN Multimedia

    Weinberg, Lee

    2007-01-01

    "AEi Systems, a world leader in power systems analysis and design, announced today that the Large Hadron Collider (LHC) at CERN (the European Centre for Nuclear Research) near Geneva, Switzerland, has engaged AEi Systems to design and develop a radiation-hard power supply for CERN's giant ATLAS particle detector." (1 page)

  18. Constraining sources of ultrahigh energy cosmic rays and shear acceleration mechanism of particles in relativistic jets

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ruoyu

    2015-06-10

    Ultrahigh energy cosmic rays are extreme energetic particles from outer space. They have aroused great interest among scientists for more than fifty years. However, due to the rarity of the events and complexity of the process of their propagation to Earth, they are still one of the biggest puzzles in modern high energy astrophysics. This dissertation is dedicated to study the origin of ultrahigh energy cosmic rays from various aspects. Firstly, we discuss a possible link between recently discovered sub-PeV/PeV neutrinos and ultrahigh energy cosmic rays. If these two kinds of particles share the same origin, the observation of neutrinos may provide additional and non-trivial constraints on the sources of ultrahigh energy cosmic rays. Secondly, we jointly employ the chemical composition measurement and the arrival directions of ultrahigh energy cosmic rays, and find a robust upper limit for distances of sources of ultrahigh energy cosmic rays above ∝55 EeV, as well as a lower limit for their metallicities. Finally, we study the shear acceleration mechanism in relativistic jets, which is a more efficient mechanism for the acceleration of higher energy particle. We compute the acceleration efficiency and the time-dependent particle energy spectrum, and explore the feature of synchrotron radiation of the accelerated particles. The possible realizations of this mechanism for acceleration of ultrahigh energy cosmic rays in different astrophysical environments is also discussed.

  19. Single-Particle States in $^{133}$Sn

    CERN Multimedia

    Huck, A

    2002-01-01

    % IS338 \\\\ \\\\ It is suggested to investigate the $\\beta^- $-decay of $^{133}$In and $^{134}$In in order to determine the single-particle states in $^{133}$Sn, which are so far unknown and needed for the shell-model description of the region close to $^{132}$Sn. Large hyper-pure Ge-detectors will be used for the $\\gamma$-ray spectroscopy. In the experiments with $^{134}$In, delayed neutrons in coincidence with $\\gamma$-rays from excited states in $^{133}$Sn provide the opportunity for a very selective detection of the states in question.

  20. GPU Acceleration of Particle-In-Cell Methods

    Science.gov (United States)

    Cowan, Benjamin; Averkin, Sergey; Cary, John; Leddy, Jarrod; Sides, Scott; Werner, Gregory

    2017-10-01

    Graphics processing units (GPUs) have become key components in many supercomputing systems, as they can provide more computations relative to their cost and power consumption than conventional processors. However, to take full advantage of this capability, they require a strict programming model which involves single-instruction multiple-data execution as well as significant constraints on memory access. To bring the full power of GPUs to bear on plasma physics problems, we must adapt the computational methods to this new programming model. We have developed a GPU implementation of the particle-in-cell (PIC) method, one of the mainstays of plasma physics simulation. This framework is highly general and enables advanced PIC features such as high order particles and absorbing boundary conditions. The main elements of the PIC loop, including field interpolation and particle deposition, are designed to optimize memory access. We describe recent progress in these algorithms, including arbitrary grid types and multiple GPUs per node. Work supported by DARPA Contract No. W31P4Q-16-C-0009.

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

    Energy Technology Data Exchange (ETDEWEB)

    Aurand, Bastian

    2012-06-20

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

  2. Acceleration of Solar Energetic Particles at a Fast Traveling Shock in Non-uniform Coronal Conditions

    Science.gov (United States)

    Le Roux, J. A.; Arthur, A. D.

    2017-09-01

    Time-dependent solar energetic particle (SEP) acceleration is investigated at a fast, nearly parallel spherical traveling shock in the strongly non-uniform corona by solving the standard focused transport equation for SEPs and transport equations for parallel propagating Alfvén waves that form a set of coupled equations. This enables the modeling of self-excitation of Alfvén waves in the inertial range by SEPs ahead of the shock and its role in enhancing the efficiency of the diffusive shock acceleration (DSA) of SEPs in a self-regulatory fashion. Preliminary results suggest that, because of the highly non-uniform coronal conditions that the shock encounters, both DSA and wave excitation are highly time-dependent processes. Thus, DSA spectra of SEPs strongly deviate from the simple power-law prediction of standard steady-state DSA theory and initially strong wave excitation weakens rapidly. Consequently, the ability of DSA to produce high energy SEPs in the corona of ∼1 GeV, as observed in the strongest gradual SEP events, appears to be strongly curtailed at a fast nearly parallel shock, but further research is needed before final conclusions can be drawn.

  3. Angular momentum transport and particle acceleration during magnetorotational instability in a kinetic accretion disk.

    Science.gov (United States)

    Hoshino, Masahiro

    2015-02-13

    Angular momentum transport and particle acceleration during the magnetorotational instability (MRI) in a collisionless accretion disk are investigated using three-dimensional particle-in-cell simulation. We show that the kinetic MRI can provide not only high-energy particle acceleration but also enhancement of angular momentum transport. We find that the plasma pressure anisotropy inside the channel flow with p(∥)>p(⊥) induced by active magnetic reconnection suppresses the onset of subsequent reconnection, which, in turn, leads to high-magnetic-field saturation and enhancement of the Maxwell stress tensor of angular momentum transport. Meanwhile, during the quiescent stage of reconnection, the plasma isotropization progresses in the channel flow and the anisotropic plasma with p(⊥)>p(∥) due to the dynamo action of MRI outside the channel flow contribute to rapid reconnection and strong particle acceleration. This efficient particle acceleration and enhanced angular momentum transport in a collisionless accretion disk may explain the origin of high-energy particles observed around massive black holes.

  4. On the transport and acceleration of solar flare particles in a coronal loop

    Science.gov (United States)

    Ryan, James M.; Lee, Martin A.

    1991-01-01

    The turbulent environment of a flaring solar coronal loop directly affects the population of particles to be accelerated or already accelerated. Under the assumption of a uniform turbulent MHD wave field within the loop, the behavior of a particle distribution as it interacts with the turbulence is discussed, including particle precipitation to the footpoints of the loop and the evolution of the energy distribution as the particles undergo second-order stochastic acceleration. Two cases are discussed in detail: (1) particles spatially diffusing within the loop and precipitating with minimal acceleration in the short time scale of an impulsive event and (2) particles diffusing in both real and momentum space in a long duration event. Collisional losses due to ambient electrons are included. The gamma-ray flare of June 3, 1982 is modeled, and good agreement is obtained between predicted and observed time profiles if the loop length is 100,000 km with an intrinsic spatial diffusion time of 100-450 s. It follows that the production of high-energy neutrons and pi mesons extends over a time scale of 1000 s as observed.

  5. Additional acceleration of solar-wind particles in current sheets of the heliosphere

    Directory of Open Access Journals (Sweden)

    V. Zharkova

    2015-04-01

    Full Text Available Particles of fast solar wind in the vicinity of the heliospheric current sheet (HCS or in a front of interplanetary coronal mass ejections (ICMEs often reveal very peculiar energy or velocity profiles, density distributions with double or triple peaks, and well-defined streams of electrons occurring around or far away from these events. In order to interpret the parameters of energetic particles (both ions and electrons measured by the WIND spacecraft during the HCS crossings, a comparison of the data was carried out with 3-D particle-in-cell (PIC simulations for the relevant magnetic topology (Zharkova and Khabarova, 2012. The simulations showed that all the observed particle-energy distributions, densities, ion peak velocities, electron pitch angles and directivities can be fitted with the same model if the heliospheric current sheet is in a status of continuous magnetic reconnection. In this paper we present further observations of the solar-wind particles being accelerated to rather higher energies while passing through the HCS and the evidence that this acceleration happens well before the appearance of the corotating interacting region (CIR, which passes through the spacecraft position hours later. We show that the measured particle characteristics (ion velocity, electron pitch angles and the distance at which electrons are turned from the HCS are in agreement with the simulations of additional particle acceleration in a reconnecting HCS with a strong guiding field as measured by WIND. A few examples are also presented showing additional acceleration of solar-wind particles during their passage through current sheets formed in a front of ICMEs. This additional acceleration at the ICME current sheets can explain the anticorrelation of ion and electron fluxes frequently observed around the ICME's leading front. Furthermore, it may provide a plausible explanation of the appearance of bidirectional "strahls" (field-aligned most energetic

  6. CERN Accelerator School: Intensity Limitations in Particle Beams | 2-11 November

    CERN Multimedia

    2015-01-01

    Registration is now open for the CERN Accelerator School’s specialised course on Intensity Limitations in Particle Beams, to be held at CERN between 2 and 11 November 2015.   This course will mainly be of interest to staff in accelerator laboratories, university departments and companies manufacturing accelerator equipment. Many accelerators and storage rings, whether intended for particle physics experiments, synchrotron light sources or industrial applications, require beams of high brightness and the highest possible intensities. A good understanding of the possible limitations is required to achieve the desired performance. The programme for this course will cover the interaction of beams with their surroundings, with other beams and further collective effects. Lectures on the effects and possible mitigations will be complemented by tutorials. Further information can be found at: http://cas.web.cern.ch/cas/Intensity-Limitations-2015/IL-advert.html   http:/...

  7. Cryogenics for high-energy particle accelerators: highlights from the first fifty years

    CERN Document Server

    AUTHOR|(CDS)2067931

    2016-01-01

    Applied superconductivity has become a key technology for high-energy particle accelerators, allowing to reach higher beam energy while containing size, capital expenditure and operating costs. Large and powerful cryogenic systems are therefore ancillary to low-temperature superconducting accelerator devices – magnets and high-frequency cavities – distributed over multi-kilometre distances and operating generally close to the normal boiling point of helium, but also above 4.2 K in supercritical and down to below 2 K in superfluid. Additionally, low-temperature operation in accelerators may also be required by considerations of ultra-high vacuum, limited stored energy and beam stability. We discuss the rationale for cryogenics in high-energy particle accelerators, review its development over the past half-century and present its outlook in future large projects, with reference to the main engineering domains of cryostat design and heat loads, cooling schemes, efficient power refrigeration and cryogenic flu...

  8. Design of a high DC voltage generator and D-T fuser based on particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Wagner L.; Campos, Tarcisio P.R., E-mail: wagnerleite@ufmg.b, E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (DEN/ UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2011-07-01

    This paper approaches a design and simulation of a high voltage Cockcroft Walton multiplier and a compact size deuteron accelerator addressed in neutron generation by d-t fusion. We proposed a circuit arrangement, which was led to simulations. The particle accelerator was computer-generated providing particle transport and electric potential analysis. As results, the simulated voltage multiplier achieved 119 kV, and the accelerator presented a deuteron beam current up to 15 mA, achieving energies in order to 100 keV. In conclusion, the simulation motivates experimental essays in order to investigate the viability of a deuteron accelerator powered by a Cockcroft-Walton source. Such d-t fusor shall produce an interesting ion beam profile, reaching energy values near the d-t fusion cross section peak. (author)

  9. Cryogenics for high-energy particle accelerators: highlights from the first fifty years

    Science.gov (United States)

    Lebrun, Ph

    2017-02-01

    Applied superconductivity has become a key technology for high-energy particle accelerators, allowing to reach higher beam energy while containing size, capital expenditure and operating costs. Large and powerful cryogenic systems are therefore ancillary to low-temperature superconducting accelerator devices - magnets and high-frequency cavities - distributed over multi-kilometre distances and operating generally close to the normal boiling point of helium, but also above 4.2 K in supercritical and down to below 2 K in superfluid. Additionally, low-temperature operation in accelerators may also be required by considerations of ultra-high vacuum, limited stored energy and beam stability. We discuss the rationale for cryogenics in high-energy particle accelerators, review its development over the past half-century and present its outlook in future large projects, with reference to the main engineering domains of cryostat design and heat loads, cooling schemes, efficient power refrigeration and cryogenic fluid management.

  10. Particle acceleration at a termination shock. I - Application to the solar wind and the anomalous component

    Science.gov (United States)

    Jokipii, J. R.

    1986-01-01

    The results of a numerical study of the diffusive acceleration of charged particles at the termination shock of the solar wind are reported. In the model a realistic magnetic field structure is employed which is similar to that observed in the solar wind. In addition to causing spatial variation of the diffusion tensor, a major effect of the magnetic field is to cause guiding-center drifts of the accelerated particles, both in the solar wind and at the shock. It is demonstrated that the inclusion of the drifts has a large effect on the acceleration. It is concluded, furthermore, that acceleration at the termination shock, in conjunction with drifts, can explain several observed features of the anomalous component.

  11. Accomplishments of the heavy electron particle accelerator program

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D. [Fermilab; Stratakis, D. [Fermilab; Palmer, M. [Brookhaven; Delahaye, J-P [SLAC; Summers, D. [Mississippi U.; Ryne, R. [LBNL, Berkeley; Cummings, M. A. [MUONS Inc.

    2016-10-18

    The Muon Accelerator Program (MAP) has completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of heavy lepton colliders (HLCs) from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a μ storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of νe ($\\bar{ve}$) and $\\bar{vμ}$ (νμ) beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components have been obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and the precise physics goals become apparent.

  12. The Black Hole Particle Accelerator as a Machine to make Baby Universes

    CERN Document Server

    Hamilton, A J S

    2013-01-01

    General relativity predicts that the inner horizon of an astronomically realistic rotating black hole is subject to the mass inflation instability. The inflationary instability acts like a gravity-powered particle accelerator of extraordinary power, accelerating accreted streams of particles along the principal outgoing and ingoing null directions at the inner horizon to collision energies that would, if nothing intervened, typically exceed exponentially the Planck energy. The inflationary instability is fueled by ongoing accretion, and is occurring inevitably in essentially every black hole in our Universe. This extravagant machine, the Black Hole Particle Accelerator, has the hallmarks of a device to make baby universes. Since collisions are most numerous inside supermassive black holes, reproductive efficiency requires our Universe to make supermassive black holes efficiently, as is observed.

  13. Electron cloud studies for CERN particle accelerators and simulation code development

    OpenAIRE

    Iadarola, Giovanni

    2014-01-01

    In a particle accelerator free electrons in the beam chambers can be generated by different mechanisms like the ionization of the residual gas or the photoemission from the chamber’s wall due to the synchrotron radiation emitted by the beam. The electromagnetic field of the beam can accelerate these electrons and project them onto the chamber’s wall. According to their impact energy and to the Secondary Electron Yield (SEY) of the surface, secondary electrons can be generated. Especially...

  14. Energy Release and Particle Acceleration in Flares: Summary and Future Prospects

    Science.gov (United States)

    Lin, R. P.

    2011-09-01

    RHESSI measurements relevant to the fundamental processes of energy release and particle acceleration in flares are summarized. RHESSI's precise measurements of hard X-ray continuum spectra enable model-independent deconvolution to obtain the parent electron spectrum. Taking into account the effects of albedo, these show that the low energy cut-off to the electron power-law spectrum is typically ≲tens of keV, confirming that the accelerated electrons contain a large fraction of the energy released in flares. RHESSI has detected a high coronal hard X-ray source that is filled with accelerated electrons whose energy density is comparable to the magnetic-field energy density. This suggests an efficient conversion of energy, previously stored in the magnetic field, into the bulk acceleration of electrons. A new, collisionless (Hall) magnetic reconnection process has been identified through theory and simulations, and directly observed in space and in the laboratory; it should occur in the solar corona as well, with a reconnection rate fast enough for the energy release in flares. The reconnection process could result in the formation of multiple elongated magnetic islands, that then collapse to bulk-accelerate the electrons, rapidly enough to produce the observed hard X-ray emissions. RHESSI's pioneering γ-ray line imaging of energetic ions, revealing footpoints straddling a flare loop arcade, has provided strong evidence that ion acceleration is also related to magnetic reconnection. Flare particle acceleration is shown to have a close relationship to impulsive Solar Energetic Particle (SEP) events observed in the interplanetary medium, and also to both fast coronal mass ejections and gradual SEP events. New instrumentation to provide the high sensitivity and wide dynamic range hard X-ray and γ-ray measurements, plus energetic neutral atom (ENA) imaging of SEPs above ˜2 R⊙, will enable the next great leap forward in understanding particle acceleration and

  15. Particle acceleration and production of energetic photons in SN1987A

    Science.gov (United States)

    Gaisser, T. K.; Stanev, Todor; Harding, Alice

    1987-01-01

    A pulsar wind model for the acceleration of particles in SN1987A is discussed. The expected photon flux is investigated in terms of the spectrum of parent protons and electrons, the nature of the region in which they propagate after acceleration, and the magnetic field and radiation environment which determines the subsequent fate of produced photons. The model is found to produce observable signals if the spin period of the pulsar is 10 ms or less.

  16. Entanglement between particle partitions in itinerant many-particle states

    NARCIS (Netherlands)

    Haque, M.; Zozulya, O.S.; Schoutens, K.

    2009-01-01

    We review 'particle-partitioning entanglement' for itinerant many-particle systems. This is defined as the entanglement between two subsets of particles making up the system. We identify generic features and mechanisms of particle entanglement that are valid over whole classes of itinerant quantum

  17. Extragalactic circuits, transmission lines, and CR particle acceleration

    CERN Document Server

    Kronberg, Philipp P

    2014-01-01

    A non-negligible fraction of a Supermassive Black Hole's (SMBH) rest mass energy gets transported into extragalactic space by a remarkable process in jets which are incompletely understood. What are the physical processes which transport this energy? It is likely that the energy flows electromagnetically, rather than via a particle beam flux. The deduced electromagnetic fields may produce particles of energy as high as $\\sim 10^{20}$ eV. The energetics of SMBH accretion disk models and the electromagnetic energy transfer imply that a SMBH should generate a $10^{18} - 10^{19}$ Amp\\`eres current close to the black hole and its accretion disk. We describe the so far best observation-based estimate of the magnitude of the current flow along the axis of the jet extending from the nucleus of the active galaxy in 3C303. The current is measured to be $I \\sim 10^{18}$ Amp\\`eres at $\\sim 40$ kpc away from the AGN. This indicates that organized current flow remains intact over multi-kpc distances. The electric current $...

  18. A Parallel Particle Swarm Optimization Algorithm Accelerated by Asynchronous Evaluations

    Science.gov (United States)

    Venter, Gerhard; Sobieszczanski-Sobieski, Jaroslaw

    2005-01-01

    A parallel Particle Swarm Optimization (PSO) algorithm is presented. Particle swarm optimization is a fairly recent addition to the family of non-gradient based, probabilistic search algorithms that is based on a simplified social model and is closely tied to swarming theory. Although PSO algorithms present several attractive properties to the designer, they are plagued by high computational cost as measured by elapsed time. One approach to reduce the elapsed time is to make use of coarse-grained parallelization to evaluate the design points. Previous parallel PSO algorithms were mostly implemented in a synchronous manner, where all design points within a design iteration are evaluated before the next iteration is started. This approach leads to poor parallel speedup in cases where a heterogeneous parallel environment is used and/or where the analysis time depends on the design point being analyzed. This paper introduces an asynchronous parallel PSO algorithm that greatly improves the parallel e ciency. The asynchronous algorithm is benchmarked on a cluster assembled of Apple Macintosh G5 desktop computers, using the multi-disciplinary optimization of a typical transport aircraft wing as an example.

  19. Particle acceleration by wave scattering off dielectric spheres at whispering-gallery-mode resonance

    Directory of Open Access Journals (Sweden)

    Władysław Żakowicz

    2007-10-01

    Full Text Available The large electromagnetic fields, created in wave scattering near a perfect dielectric sphere at the condition of whispering-gallery-mode resonances, are investigated as driving units for high energy charged particle accelerators. For optimal trajectories passing near the scattering sphere, particle coupling with the field reduces to very short intervals, of the order of the wave period. Interacting fields can be almost 1000 times stronger than that in the incident wave. An example considered indicates that the instantaneous energy yield during this strong coupling interval is equivalent to ∼30  GeV/m, assuming the incident electric field E_{0}=100  MV/m. It was shown that the particle transverse deflection is negligible if the phase of the particle is optimal for acceleration. Hence, the acceleration process can be repeated many times. A rough estimate of the energy gain in a periodic chain of such elementary accelerating unit cells gives ΔEnergy/m≈5  GeV/m, which is several hundred times more than in contemporary operating and projected accelerators. Preliminary estimates of absorption losses in the scheme are given.

  20. Acceleration and particle transport in collisionless plasma in the process of dipolarization and nonstationary turbulence

    Science.gov (United States)

    Zhukova, E. I.; Malova, Kh. V.; Popov, V. Yu.; Grigorenko, E. E.; Petrukovich, A. A.; Zelenyi, L. M.

    2017-11-01

    This work is devoted to studying the processes of the acceleration of plasma particles in thin current sheets that appear during magnetospheric substorms in the Earth's magnetosphere tail. A numerical model of magnetic dipolarization accompanied by plasma turbulence has been constructed and studied. The model allows one to investigate the particle acceleration due to the action of three principal mechanisms: (1) plasma turbulence; (2) magnetic dipolarization; (3) their simultaneous action. For the given velocity kappa-distributions, we obtained energy spectra of three types of accelerated particles, i.e., protons p +, ions of oxygen O+, and electrons e -. It has been shown that the combined mechanism of dipolarization with turbulence (3) makes the largest contribution to the increase in the energy of protons and heavy ions as compared with a separate action of each of mechanisms (1) and (2); in this case, electrons accelerate less. The consideration of the joint action of acceleration mechanisms (1) and (2) can explain the apparition of particles with energies on the order of magnitude equal to hundreds keV in the Earth's magnetosphere tail.

  1. Plasma Wakefield Excitation in a Cold Magnetized Plasma for Particle Acceleration

    Science.gov (United States)

    Karmakar, Mithun; Chakrabarti, Nikhil; Sengupta, Sudip

    2017-10-01

    A numerical study has been done to find a travelling wave solution for a highly relativistic electron beam driven cold magnetized plasma. The presence of magnetic field has an effect to reduce thetransformer ratio (the ratio of energy gain to the drive beam energy) from its unmagnetized value. The effects of beam shape and the non-relativistic ion motion on the nonlinear structures of different dynamical variables are also discussed. The results owe its significance in the laboratory context of particle acceleration or in the study of generation of ultrahigh accelerating charged particle by strong plasma wave in astrophysical situations. Department of Atomic Energy of India and Homi Bhaba National Institute.

  2. The Future of Superconducting Technology for Particle Accelerators

    CERN Document Server

    Yamamoto, Akira

    2015-01-01

    Introduction: - Colliders constructed and operated - Future High Energy Colliders under Study - Superconducting Phases and Applications - Possible Choices among SC Materials Superconducting Magnets and the Future - Advances in SC Magnets for Accelerators - Nb3Sn for realizing Higher Field - NbTi to Nb3Sn for realizing High Field (> 10 T) - HL-LHC as a critical milestone for the Future of Acc. Magnet Technology - Nb3Sn Superconducting Magnets (> 11 T)and MgB2 SC Links for HL-LHC - HL-LHC, 11T Dipole Magnet - Nb3Sn Quadrupole (MQXF) at IR - Future Circular Collider Study - Conductor development (1998-2008) - Nb3Sn conductor program - 16 T Dipole Options and R&D sharing - Design Study and Develoment for SppC in China - High-Field Superconductor and Magnets - HTS Block Coil R&D for 20 T - Canted Cosine Theta (CCT) Coil suitable with Brittle HTS Conductor - A topic at KEK: S-KEKB IRQs just integrated w/ BELLE-II ! Superconducting RF and the Future - Superconducting Phases and Applications - Poss...

  3. Extragalactic circuits, transmission lines, and CR particle acceleration

    Directory of Open Access Journals (Sweden)

    Kronberg Philipp P.

    2015-01-01

    Full Text Available A non-negligible fraction of a Supermassive Black Hole's (SMBH rest mass energy gets transported into extragalactic space by a remarkable process in jets which are incompletely understood. What are the physical processes which transport this energy? It is likely that the energy flows electromagnetically, rather than via a particle beam flux. The deduced electromagnetic fields may produce particles of energy as high as ∼ 1020 eV. The energetics of SMBH accretion disk models and the electromagnetic energy transfer imply that a SMBH should generate a 1018 − 1019 Ampères current close to the black hole and its accretion disk. We describe the so far best observation-based estimate of the magnitude of the current flow along the axis of the jet extending from the nucleus of the active galaxy in 3C303. The current is measured to be I ∼ 1018 Ampères at ∼ 40 kpc away from the AGN. This indicates that organised current flow remains intact over multi-kpc distances. The electric current I transports electromagnetic power into free space, P = I2Z, where Z ∼ 30 Ohms is related to the impedance of free space, and this points to the existence of cosmic electric circuit. The associated electric potential drop, V = IZ, is of the order of that required to generate Ultra High Energy Cosmic Rays (UHECR. We also explore further implications, including disruption/deflection of the power flow and also why such measurements, exemplified by those on 3C303, are currently very difficult to make and to unambiguously interpret. This naturally leads to the topic of how such measurements can be extended and improved in the future. We describe the analogy of electromagnetically dominated jets with transmission lines. High powered jets in vacuo can be understood by approximate analogy with a waveguide. The importance of inductance, impedance, and other laboratory electrical concepts are discussed in this context.

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

    OpenAIRE

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

    2013-01-01

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

  5. Reconnection and particle acceleration in interacting flux ropes - I. Magnetohydrodynamics and test particles in 2.5D

    Science.gov (United States)

    Ripperda, B.; Porth, O.; Xia, C.; Keppens, R.

    2017-05-01

    Magnetic reconnection and non-thermal particle distributions associated with current-driven instabilities are investigated by means of resistive magnetohydrodynamics (MHD) simulations combined with relativistic test particle methods. We propose a system with two parallel, repelling current channels in an initially force-free equilibrium, as a simplified representation of flux ropes in a stellar magnetosphere. The current channels undergo a rotation and separation on Alfvénic time-scales, forming secondary islands and (up to tearing unstable) current sheets in which non-thermal energy distributions are expected to develop. Using the recently developed particle module of our open-source grid-adaptive mpi-amrvac software, we simulate MHD evolution combined with test particle treatments in MHD snapshots. We explore under which plasma-β conditions the fastest reconnection occurs in 2.5D scenarios, and in these settings, test particles are evolved. We quantify energy distributions, acceleration mechanisms, relativistic corrections to the particle equations of motion and effects of resistivity in magnetically dominated proton-electron plasmas. Due to large resistive electric fields and indefinite acceleration of particles in the infinitely long current channels, hard energy spectra are found in 2.5D configurations. Solutions to these numerical artefacts are proposed for both 2.5D setups and future 3D work. We discuss the MHD of an additional kink instability in 3D setups and the expected effects on energy distributions. The obtained results hold as a proof-of-principle for test particle approaches in MHD simulations, relevant to explore less idealized scenarios like solar flares and more exotic astrophysical phenomena, like black hole flares, magnetar magnetospheres and pulsar wind nebulae.

  6. Anomalous Distributions of Primary Cosmic Rays as Evidence for Time-dependent Particle Acceleration in Supernova Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yiran; Liu, Siming; Yuan, Qiang, E-mail: liusm@pmo.ac.cn [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2017-07-20

    Recent precise measurements of cosmic-ray (CR) spectra show that the energy distribution of protons is softer than those of heavier nuclei, and there are spectral hardenings for all nuclear compositions above ∼200 GV. Models proposed for these anomalies generally assume steady-state solutions of the particle acceleration process. We show that if the diffusion coefficient has a weak dependence on the particle rigidity near shock fronts of supernova remnants (SNRs), time-dependent solutions of the linear diffusive shock acceleration at two stages of SNR evolution can naturally account for these anomalies. The high-energy component of CRs is dominated by acceleration in the free expansion and adiabatic phases with enriched heavy elements and a high shock speed. The low-energy component may be attributed to acceleration by slow shocks propagating in dense molecular clouds with low metallicity in the radiative phase. Instead of a single power-law distribution, the spectra of time-dependent solutions soften gradually with the increase of energy, which may be responsible for the “knee” of CRs.

  7. Diaphragm flange and method for lowering particle beam impedance at connected beam tubes of a particle accelerator

    Science.gov (United States)

    Biallas, George Herman

    2017-07-04

    A diaphragm flange for connecting the tubes in a particle accelerator while minimizing beamline impedance. The diaphragm flange includes an outer flange and a thin diaphragm integral with the outer flange. Bolt holes in the outer flange provide a means for bolting the diaphragm flange to an adjacent flange or beam tube having a mating bolt-hole pattern. The diaphragm flange includes a first surface for connection to the tube of a particle accelerator beamline and a second surface for connection to a CF flange. The second surface includes a recessed surface therein and a knife-edge on the recessed surface. The diaphragm includes a thickness that enables flexing of the integral diaphragm during assembly of beamline components. The knife-edge enables compression of a soft metal gasket to provide a leak-tight seal.

  8. Future trends in cancer therapy with particle accelerators

    CERN Document Server

    Amaldi, Ugo

    2004-01-01

    Hadrontherapy is the radiotherapy technique that uses protons, neutrons or carbon ions. Protons and ions, being, heavy charged particles, allow a more conformal treatment than X-rays and thus spare better the surrounding healthy tissues. By now about 35000 patients have been treated worldwide with protons and about 1600 with carbon ions. Since few years protontherapy of deep-seated tumours is booming with two hospital centres running in USA and three under construction. Four centres are treating patients in Japan. The list of constructions going on elsewhere is long: two in China, one, in Germany, one in Korea, one in Switzerland. But the future hopes for a qualitatively different radiotherapy are centred on carbon ions: they have a larger biological effectiveness than X-rays and protons and are particularly suited to treat radio resistant tumours, as indicated by the encouraging results obtained on about 1400 patients in HIMAC (Chiba, Japan) and on about 200 patients at GSI (Darmstadt). Two carbon centres ar...

  9. Particle accelerators from Big Bang physics to hadron therapy

    CERN Document Server

    Amaldi, Ugo

    2015-01-01

    The theoretical physicist Victor “Viki” Weisskopf, Director-General of CERN from 1961 to 1965, once “There are three kinds of physicists, namely the machine builders, the experimental physicists, and the theoretical physicists. […] The machine builders are the most important ones, because if they were not there, we would not get into this small-scale region of space. If we compare this with the discovery of America, the machine builders correspond to captains and ship builders who really developed the techniques at that time. The experimentalists were those fellows on the ships who sailed to the other side of the world and then landed on the new islands and wrote down what they saw. The theoretical physicists are those who stayed behind in Madrid and told Columbus that he was going to land in India.” Rather than focusing on the theoretical physicists, as most popular science books on particle physics do, this beautifully written and also entertaining book is different in that, firstly, the main foc...

  10. Solid-State Video Camera for the Accelerator Environment

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R

    2004-05-27

    Solid-State video cameras employing CMOS technology have been developed and tested for several years in the SLAC accelerator; notably the PEPII (BaBar) injection lines. They have proven much more robust than their CCD counterparts in radiation areas. Repair is simple, inexpensive, and generates very little radioactive waste.

  11. Proceeding of the 1999 Particle Accelerator Conference. Volume 1

    Science.gov (United States)

    1999-04-02

    80309-0390, USA Peking University, Office of the President, Peking University, Hai Dian , Beijing, 100871, China, Peoples Republic of Cheng, Daniel W...Brookhaven Technology Group, Inc.; J.Smedley, State University of New York, Stony Brook; X.E.Lin, A .O dian , SLA C, Stanford, CA...System", these proceedings.beam duct CuNi insert [8] G. Blokesch, M. Negrazus, K. Wille, Nucl. Inst. and Meth. in Phys. Figure 3. One of 3 girder

  12. Real-time separation of non-stationary sound fields with pressure and particle acceleration measurements.

    Science.gov (United States)

    Bi, Chuan-Xing; Geng, Lin; Zhang, Xiao-Zheng

    2014-06-01

    To extract the desired non-stationary sound field generated by a target source in the presence of disturbing sources, a real-time sound field separation method with pressure and particle acceleration measurements is proposed. In this method, the pressure and particle acceleration signals at a time instant are first measured on one measurement plane, where the particle acceleration is obtained by the finite difference approximation with the aid of an auxiliary measurement plane; then, the desired pressure signal generated by the target source at the same time instant can be extracted in a timely manner, by a simple superposition of the measured pressure and the convolution between the measured particle acceleration and the derived impulse response function. Thereby, the proposed method possesses a significant feature of real-time separation of non-stationary sound fields, which provides the potential to in situ analyze the radiation characteristics of a non-stationary source. The proposed method was examined through numerical simulation and experiment. Results demonstrated that the proposed method can not only extract the desired time-evolving pressure signal generated by the target source at any space point, but can also obtain the desired spatial distribution of the pressure field generated by the target source at any time instant.

  13. High-energy particle acceleration by explosive electromagnetic interaction in an accretion disk

    Science.gov (United States)

    Haswell, C. A.; Tajima, T.; Sakai, J.-I.

    1992-01-01

    By examining electromagnetic field evolution occurring in an accretion disk around a compact object, we arrive at an explosive mechanism of particle acceleration. Flux-freezing in the differentially rotating disk causes the seed and/or generated magnetic field to wrap up tightly, becoming highly sheared and locally predominantly azimuthal in orientation. We show how asymptotically nonlinear solutions for the electromagnetic fields may arise in isolated plasma blobs as a result of the driving of the fluid equations by the accretion flow. These fields are capable of rapidly accelerating charged particles from the disk. Acceleration through the present mechanism from AGN can give rise to energies beyond 10 exp 20 eV. Such a mechanism may present an explanation for the extragalactic origin of the most energetic observed cosmic rays.

  14. Effect of acceleration on localized fermionic Gaussian states: From vacuum entanglement to maximally entangled states

    Science.gov (United States)

    Richter, Benedikt; Lorek, Krzysztof; Dragan, Andrzej; Omar, Yasser

    2017-04-01

    We study the effects of acceleration on fermionic Gaussian states of localized modes of a Dirac field. We consider two wave packets in a Gaussian state and transform these to an accelerated frame of reference. In particular, we formulate the action of this transformation as a fermionic quantum channel. Having developed the general framework for fermions, we then investigate the entanglement of the vacuum, as well as the entanglement in Bell states. We find that with increasing acceleration vacuum entanglement increases, while the entanglement of Bell states decreases. Notably, our results have an immediate operational meaning given the localization of the modes.

  15. The Advanced Composition Explorer Shock Database and Application to Particle Acceleration Theory

    Science.gov (United States)

    Parker, L. Neergaard; Zank, G. P.

    2015-01-01

    The theory of particle acceleration via diffusive shock acceleration (DSA) has been studied in depth by Gosling et al. (1981), van Nes et al. (1984), Mason (2000), Desai et al. (2003), Zank et al. (2006), among many others. Recently, Parker and Zank (2012, 2014) and Parker et al. (2014) using the Advanced Composition Explorer (ACE) shock database at 1 AU explored two questions: does the upstream distribution alone have enough particles to account for the accelerated downstream distribution and can the slope of the downstream accelerated spectrum be explained using DSA? As was shown in this research, diffusive shock acceleration can account for a large population of the shocks. However, Parker and Zank (2012, 2014) and Parker et al. (2014) used a subset of the larger ACE database. Recently, work has successfully been completed that allows for the entire ACE database to be considered in a larger statistical analysis. We explain DSA as it applies to single and multiple shocks and the shock criteria used in this statistical analysis. We calculate the expected injection energy via diffusive shock acceleration given upstream parameters defined from the ACE Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) data to construct the theoretical upstream distribution. We show the comparison of shock strength derived from diffusive shock acceleration theory to observations in the 50 keV to 5 MeV range from an instrument on ACE. Parameters such as shock velocity, shock obliquity, particle number, and time between shocks are considered. This study is further divided into single and multiple shock categories, with an additional emphasis on forward-forward multiple shock pairs. Finally with regard to forward-forward shock pairs, results comparing injection energies of the first shock, second shock, and second shock with previous energetic population will be given.

  16. Laser-Induced Linear-Field Particle Acceleration in Free Space.

    Science.gov (United States)

    Wong, Liang Jie; Hong, Kyung-Han; Carbajo, Sergio; Fallahi, Arya; Piot, Philippe; Soljačić, Marin; Joannopoulos, John D; Kärtner, Franz X; Kaminer, Ido

    2017-09-11

    Linear-field particle acceleration in free space (which is distinct from geometries like the linac that requires components in the vicinity of the particle) has been studied for over 20 years, and its ability to eventually produce high-quality, high energy multi-particle bunches has remained a subject of great interest. Arguments can certainly be made that linear-field particle acceleration in free space is very doubtful given that first-order electron-photon interactions are forbidden in free space. Nevertheless, we chose to develop an accurate and truly predictive theoretical formalism to explore this remote possibility when intense, few-cycle electromagnetic pulses are used in a computational experiment. The formalism includes exact treatment of Maxwell's equations and exact treatment of the interaction among the multiple individual particles at near and far field. Several surprising results emerge. We find that electrons interacting with intense laser pulses in free space are capable of gaining substantial amounts of energy that scale linearly with the field amplitude. For example, 30 keV electrons (2.5% energy spread) are accelerated to 61 MeV (0.5% spread) and to 205 MeV (0.25% spread) using 250 mJ and 2.5 J lasers respectively. These findings carry important implications for our understanding of ultrafast electron-photon interactions in strong fields.

  17. Numerical Study of Correlation of Fluid Particle Acceleration and Turbulence Intensity in Swirling Flow

    Directory of Open Access Journals (Sweden)

    Nan Gui

    2015-01-01

    Full Text Available Numerical investigation of correlation between the fluid particle acceleration and the intensity of turbulence in swirling flows at a large Reynolds number is carried out via direct numerical simulation. A weak power-law form correlation ur.m.sE~C(aLφ between the Lagrangian acceleration and the Eulerian turbulence intensity is derived. It is found that the increase of the swirl level leads to the increase of the exponent φ and the trajectory-conditioned correlation coefficient ρ(aL,uE and results in a weak power-law augmentation of the acceleration intermittency. The trajectory-conditioned convection of turbulence fluctuation in the Eulerian viewpoint is generally linearly proportional to the fluctuation of Lagrangian accelerations, indicating a weak but clear relation between the Lagrangian intermittency and Eulerian intermittency effects. Moreover, except the case with vortex breakdown, the weak linear dependency is maintained when the swirl levels change, only with the coefficient of slope varied.

  18. Digital Signal Processing and Generation for a DC Current Transformer for Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Zorzetti, Silvia [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2013-01-01

    The thesis topic, digital signal processing and generation for a DC current transformer, focuses on the most fundamental beam diagnostics in the field of particle accelerators, the measurement of the beam intensity, or beam current. The technology of a DC current transformer (DCCT) is well known, and used in many areas, including particle accelerator beam instrumentation, as non-invasive (shunt-free) method to monitor the DC current in a conducting wire, or in our case, the current of charged particles travelling inside an evacuated metal pipe. So far, custom and commercial DCCTs are entirely based on analog technologies and signal processing, which makes them inflexible, sensitive to component aging, and difficult to maintain and calibrate.

  19. Adiabatic description of capture into resonance and surfatron acceleration of charged particles by electromagnetic waves.

    Science.gov (United States)

    Artemyev, A V; Neishtadt, A I; Zelenyi, L M; Vainchtein, D L

    2010-12-01

    We present an analytical and numerical study of the surfatron acceleration of nonrelativistic charged particles by electromagnetic waves. The acceleration is caused by capture of particles into resonance with one of the waves. We investigate capture for systems with one or two waves and provide conditions under which the obtained results can be applied to systems with more than two waves. In the case of a single wave, the once captured particles never leave the resonance and their velocity grows linearly with time. However, if there are two waves in the system, the upper bound of the energy gain may exist and we find the analytical value of that bound. We discuss several generalizations including the relativistic limit, different wave amplitudes, and a wide range of the waves' wavenumbers. The obtained results are used for qualitative description of some phenomena observed in the Earth's magnetosphere. © 2010 American Institute of Physics.

  20. Quantum radiation produced by a uniformly accelerating charged particle in thermal random motion

    Science.gov (United States)

    Oshita, Naritaka; Yamamoto, Kazuhiro; Zhang, Sen

    2016-04-01

    We investigate the properties of quantum radiation produced by a uniformly accelerating charged particle undergoing thermal random motion, which originates from the coupling to the vacuum fluctuations of the electromagnetic field. Because the thermal random motion is regarded to result from the Unruh effect, the quantum radiation might give us hints of the Unruh effect. The energy flux of the quantum radiation is negative and smaller than that of Larmor radiation by one order in a /m , where a is the constant acceleration and m is the mass of the particle. Thus, the quantum radiation appears to be a suppression of the classical Larmor radiation. The quantum interference effect plays an important role in this unique signature. The results are consistent with the predictions of a model consisting of a particle coupled to a massless scalar field as well as those of the previous studies on the quantum effect on the Larmor radiation.

  1. A new approach to fluid-structure interaction within graphics hardware accelerated smooth particle hydrodynamics considering heterogeneous particle size distribution

    Science.gov (United States)

    Eghtesad, Adnan; Knezevic, Marko

    2017-12-01

    A corrective smooth particle method (CSPM) within smooth particle hydrodynamics (SPH) is used to study the deformation of an aircraft structure under high-velocity water-ditching impact load. The CSPM-SPH method features a new approach for the prediction of two-way fluid-structure interaction coupling. Results indicate that the implementation is well suited for modeling the deformation of structures under high-velocity impact into water as evident from the predicted stress and strain localizations in the aircraft structure as well as the integrity of the impacted interfaces, which show no artificial particle penetrations. To reduce the simulation time, a heterogeneous particle size distribution over a complex three-dimensional geometry is used. The variable particle size is achieved from a finite element mesh with variable element size and, as a result, variable nodal (i.e., SPH particle) spacing. To further accelerate the simulations, the SPH code is ported to a graphics processing unit using the OpenACC standard. The implementation and simulation results are described and discussed in this paper.

  2. Magnetic-Island Contraction and Particle Acceleration in Simulated Eruptive Solar Flares

    Science.gov (United States)

    Guidoni, S. E.; Devore, C. R.; Karpen, J. T.; Lynch, B. J.

    2016-01-01

    The mechanism that accelerates particles to the energies required to produce the observed high-energy impulsive emission in solar flares is not well understood. Drake et al. proposed a mechanism for accelerating electrons in contracting magnetic islands formed by kinetic reconnection in multi-layered current sheets (CSs). We apply these ideas to sunward-moving flux ropes (2.5D magnetic islands) formed during fast reconnection in a simulated eruptive flare. A simple analytic model is used to calculate the energy gain of particles orbiting the field lines of the contracting magnetic islands in our ultrahigh-resolution 2.5D numerical simulation. We find that the estimated energy gains in a single island range up to a factor of five. This is higher than that found by Drake et al. for islands in the terrestrial magnetosphere and at the heliopause, due to strong plasma compression that occurs at the flare CS. In order to increase their energy by two orders of magnitude and plausibly account for the observed high-energy flare emission, the electrons must visit multiple contracting islands. This mechanism should produce sporadic emission because island formation is intermittent. Moreover, a large number of particles could be accelerated in each magneto hydro dynamic-scale island, which may explain the inferred rates of energetic-electron production in flares. We conclude that island contraction in the flare CS is a promising candidate for electron acceleration in solar eruptions.

  3. MAGNETIC-ISLAND CONTRACTION AND PARTICLE ACCELERATION IN SIMULATED ERUPTIVE SOLAR FLARES

    Energy Technology Data Exchange (ETDEWEB)

    Guidoni, S. E. [The Catholic University of America, 620 Michigan Avenue Northeast, Washington, DC 20064 (United States); DeVore, C. R.; Karpen, J. T. [Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lynch, B. J., E-mail: silvina.e.guidoni@nasa.gov [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)

    2016-03-20

    The mechanism that accelerates particles to the energies required to produce the observed high-energy impulsive emission in solar flares is not well understood. Drake et al. proposed a mechanism for accelerating electrons in contracting magnetic islands formed by kinetic reconnection in multi-layered current sheets (CSs). We apply these ideas to sunward-moving flux ropes (2.5D magnetic islands) formed during fast reconnection in a simulated eruptive flare. A simple analytic model is used to calculate the energy gain of particles orbiting the field lines of the contracting magnetic islands in our ultrahigh-resolution 2.5D numerical simulation. We find that the estimated energy gains in a single island range up to a factor of five. This is higher than that found by Drake et al. for islands in the terrestrial magnetosphere and at the heliopause, due to strong plasma compression that occurs at the flare CS. In order to increase their energy by two orders of magnitude and plausibly account for the observed high-energy flare emission, the electrons must visit multiple contracting islands. This mechanism should produce sporadic emission because island formation is intermittent. Moreover, a large number of particles could be accelerated in each magnetohydrodynamic-scale island, which may explain the inferred rates of energetic-electron production in flares. We conclude that island contraction in the flare CS is a promising candidate for electron acceleration in solar eruptions.

  4. The Acceleration of Charged Particles at a Spherical Shock Moving through an Irregular Magnetic Field

    Science.gov (United States)

    Giacalone, J.

    2017-10-01

    We investigate the physics of charged-particle acceleration at spherical shocks moving into a uniform plasma containing a turbulent magnetic field with a uniform mean. This has applications to particle acceleration at astrophysical shocks, most notably, to supernovae blast waves. We numerically integrate the equations of motion of a large number of test protons moving under the influence of electric and magnetic fields determined from a kinematically defined plasma flow associated with a radially propagating blast wave. Distribution functions are determined from the positions and velocities of the protons. The unshocked plasma contains a magnetic field with a uniform mean and an irregular component having a Kolmogorov-like power spectrum. The field inside the blast wave is determined from Maxwell’s equations. The angle between the average magnetic field and unit normal to the shock varies with position along its surface. It is quasi-perpendicular to the unit normal near the sphere’s equator, and quasi-parallel to it near the poles. We find that the highest intensities of particles, accelerated by the shock, are at the poles of the blast wave. The particles “collect” at the poles as they approximately adhere to magnetic field lines that move poleward from their initial encounter with the shock at the equator, as the shock expands. The field lines at the poles have been connected to the shock the longest. We also find that the highest-energy protons are initially accelerated near the equator or near the quasi-perpendicular portion of the shock, where the acceleration is more rapid.

  5. Particle acceleration during merging-compression plasma start-up in the Mega Amp Spherical Tokamak

    Science.gov (United States)

    McClements, K. G.; Allen, J. O.; Chapman, S. C.; Dendy, R. O.; Irvine, S. W. A.; Marshall, O.; Robb, D.; Turnyanskiy, M.; Vann, R. G. L.

    2018-02-01

    Magnetic reconnection occurred during merging-compression plasma start-up in the Mega Amp Spherical Tokamak (MAST), resulting in the prompt acceleration of substantial numbers of ions and electrons to highly suprathermal energies. Accelerated field-aligned ions (deuterons and protons) were detected using a neutral particle analyser at energies up to about 20 keV during merging in early MAST pulses, while nonthermal electrons have been detected indirectly in more recent pulses through microwave bursts. However no increase in soft x-ray emission was observed until later in the merging phase, by which time strong electron heating had been detected through Thomson scattering measurements. A test-particle code CUEBIT is used to model ion acceleration in the presence of an inductive toroidal electric field with a prescribed spatial profile and temporal evolution based on Hall-MHD simulations of the merging process. The simulations yield particle distributions with properties similar to those observed experimentally, including strong field alignment of the fast ions and the acceleration of protons to higher energies than deuterons. Particle-in-cell modelling of a plasma containing a dilute field-aligned suprathermal electron component suggests that at least some of the microwave bursts can be attributed to the anomalous Doppler instability driven by anisotropic fast electrons, which do not produce measurable enhancements in soft x-ray emission either because they are insufficiently energetic or because the nonthermal bremsstrahlung emissivity during this phase of the pulse is below the detection threshold. There is no evidence of runaway electron acceleration during merging, possibly due to the presence of three-dimensional field perturbations.

  6. Automated detection and analysis of particle beams in laser-plasma accelerator simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela Mayumi; Geddes, C.G.; Cormier-Michel, E.; Bethel, E. Wes; Jacobsen, J.; Prabhat, ,; R.ubel, O.; Weber, G,; Hamann, B.

    2010-05-21

    Numerical simulations of laser-plasma wakefield (particle) accelerators model the acceleration of electrons trapped in plasma oscillations (wakes) left behind when an intense laser pulse propagates through the plasma. The goal of these simulations is to better understand the process involved in plasma wake generation and how electrons are trapped and accelerated by the wake. Understanding of such accelerators, and their development, offer high accelerating gradients, potentially reducing size and cost of new accelerators. One operating regime of interest is where a trapped subset of electrons loads the wake and forms an isolated group of accelerated particles with low spread in momentum and position, desirable characteristics for many applications. The electrons trapped in the wake may be accelerated to high energies, the plasma gradient in the wake reaching up to a gigaelectronvolt per centimeter. High-energy electron accelerators power intense X-ray radiation to terahertz sources, and are used in many applications including medical radiotherapy and imaging. To extract information from the simulation about the quality of the beam, a typical approach is to examine plots of the entire dataset, visually determining the adequate parameters necessary to select a subset of particles, which is then further analyzed. This procedure requires laborious examination of massive data sets over many time steps using several plots, a routine that is unfeasible for large data collections. Demand for automated analysis is growing along with the volume and size of simulations. Current 2D LWFA simulation datasets are typically between 1GB and 100GB in size, but simulations in 3D are of the order of TBs. The increase in the number of datasets and dataset sizes leads to a need for automatic routines to recognize particle patterns as particle bunches (beam of electrons) for subsequent analysis. Because of the growth in dataset size, the application of machine learning techniques for

  7. Doing More with Less: Cost-effective, Compact Particle Accelerators (489th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Trbojevic, Dejan [BNL Collider-Accelerator Department

    2013-10-22

    Replace a 135-ton magnet used for cancer-fighting particle therapies with a magnet that weighs only two tons? Such a swap is becoming possible thanks to new particle accelerator advances being developed by researchers at Brookhaven Lab. With an approach that combines techniques used by synchrotron accelerators with the ability to accept more energy, these new technologies could be used for more than fighting cancer. They could also decrease the lifecycle of byproducts from nuclear power plants and reduce costs for eRHIC—a proposed electron-ion collider for Brookhaven Lab that researchers from around the world would use to explore the glue that holds together the universe’s most basic building blocks and explore the proton-spin puzzle. During this lecture, Dr. Trbojevic provides an overview of accelerator technologies and techniques—particularly a non-scaling, fixed-focused alternating gradient—to focus particle beams using fewer, smaller magnets. He discusses how these technologies will benefit eRHIC and other applications, including particle therapies being developed to combat cancer.

  8. Particle accelerators, colliders, and the story of high energy physics. Charming the cosmic snake

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, Raghavan

    2012-07-01

    The Nordic mythological Cosmic Serpent, Ouroboros, is said to be coiled in the depths of the sea, surrounding the Earth with its tail in its mouth. In physics, this snake is a metaphor for the Universe, where the head, symbolizing the largest entity - the Cosmos - is one with the tail, symbolizing the smallest - the fundamental particle. Particle accelerators, colliders and detectors are built by physicists and engineers to uncover the nature of the Universe while discovering its building blocks. ''Charming the Cosmic Snake'' takes the readers through the science behind these experimental machines: the physics principles that each stage of the development of particle accelerators helped to reveal, and the particles they helped to discover. The book culminates with a description of the Large Hadron Collider, one of the world's largest and most complex machines operating in a 27-km circumference tunnel near Geneva. That collider may prove or disprove many of our basic theories about the nature of matter. The book provides the material honestly without misrepresenting the science for the sake of excitement or glossing over difficult notions. The principles behind each type of accelerator is made accessible to the undergraduate student and even to a lay reader with cartoons, illustrations and metaphors. Simultaneously, the book also caters to different levels of reader's background and provides additional materials for the more interested or diligent reader. (orig.)

  9. The present role of small particle accelerators for the study of Cultural Heritage

    Science.gov (United States)

    Mandò, P. A.; Fedi, M. E.; Grassi, N.

    2011-04-01

    The role that small particle accelerators play in the field of applications to Cultural Heritage (for material analysis and dating) is critically discussed also in comparison to other techniques, pointing out pros and cons. As to material analysis, some peculiarities of ion beam techniques may be now less unique than they were perhaps ten years ago, but these techniques can still reach unrivalled results thanks to a smart use of their potential: for instance, they can provide elemental maps and resolve layer structures. Concerning Accelerator Mass Spectrometry, its unique performance for radiocarbon dating -- as to sensitivity, precision and quasi non-destructivity -- is described, and perspectives for further improvements are presented.

  10. Understanding nature's particle accelerators using high energy gamma-ray survey instruments

    Science.gov (United States)

    Abeysekara, Anushka Udara

    Nature's particle accelerators, such as Pulsars, Pulsar Wind Nebulae, Active Galactic Nuclei and Supernova Remnants accelerate charged particles to very high energies that then produce high energy photons. The particle acceleration mechanisms and the high energy photon emission mechanisms are poorly understood phenomena. These mechanisms can be understood either by studying individual sources in detail or, alternatively, using the collective properties of a sample of sources. Recent development of GeV survey instruments, such as Fermi-LAT, and TeV survey instruments, such as Milagro, provides a large sample of high energy gamma-ray flux measurements from galactic and extra-galactic sources. In this thesis I provide constraints on GeV and TeV radiation mechanisms using the X-ray-TeV correlations and GeV-TeV correlations. My data sample was obtained from three targeted searches for extragalactic sources and two targeted search for galactic sources, using the existing Milagro sky maps. The first extragalactic candidate list consists of Fermi-LAT GeV extragalactic sources, and the second extragalactic candidate list consists of TeVCat extragalactic sources that have been detected by Imaging Atmospheric Cerenkov Telescopes (IACTs). In both extragalactic candidate lists Markarian 421 was the only source detected by Milagro. A comparison between the Markarian 421 time-averaged flux, measured by Milagro, and the flux measurements of transient states, measured by IACTs, is discussed. The third extragalactic candidate list is a list of potential TeV emitting BL Lac candidates that was synthesized using X-ray observations of BL Lac objects and a Synchrotron Self-Compton model. Milagro's sensitivity was not sufficient to detect any of those candidates. However, the 95% confidence flux upper limits of those sources were above the predicted flux. Therefore, these results provide evidence to conclude that the Synchrotron Self-Compton model for BL Lac objects is still a viable

  11. Steady state quantum discord for circularly accelerated atoms

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jiawei, E-mail: hujiawei@nbu.edu.cn [Center for Nonlinear Science and Department of Physics, Ningbo University, Ningbo, Zhejiang 315211 (China); Yu, Hongwei, E-mail: hwyu@hunnu.edu.cn [Center for Nonlinear Science and Department of Physics, Ningbo University, Ningbo, Zhejiang 315211 (China); Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081 (China)

    2015-12-15

    We study, in the framework of open quantum systems, the dynamics of quantum entanglement and quantum discord of two mutually independent circularly accelerated two-level atoms in interaction with a bath of fluctuating massless scalar fields in the Minkowski vacuum. We assume that the two atoms rotate synchronically with their separation perpendicular to the rotating plane. The time evolution of the quantum entanglement and quantum discord of the two-atom system is investigated. For a maximally entangled initial state, the entanglement measured by concurrence diminishes to zero within a finite time, while the quantum discord can either decrease monotonically to an asymptotic value or diminish to zero at first and then followed by a revival depending on whether the initial state is antisymmetric or symmetric. When both of the two atoms are initially excited, the generation of quantum entanglement shows a delayed feature, while quantum discord is created immediately. Remarkably, the quantum discord for such a circularly accelerated two-atom system takes a nonvanishing value in the steady state, and this is distinct from what happens in both the linear acceleration case and the case of static atoms immersed in a thermal bath.

  12. GPU acceleration of Eulerian-Lagrangian particle-laden turbulent flow simulations

    Science.gov (United States)

    Richter, David; Sweet, James; Thain, Douglas

    2017-11-01

    The Lagrangian point-particle approximation is a popular numerical technique for representing dispersed phases whose properties can substantially deviate from the local fluid. In many cases, particularly in the limit of one-way coupled systems, large numbers of particles are desired; this may be either because many physical particles are present (e.g. LES of an entire cloud), or because the use of many particles increases statistical convergence (e.g. high-order statistics). Solving the trajectories of very large numbers of particles can be problematic in traditional MPI implementations, however, and this study reports the benefits of using graphical processing units (GPUs) to integrate the particle equations of motion while preserving the original MPI version of the Eulerian flow solver. It is found that GPU acceleration becomes cost effective around one million particles, and performance enhancements of up to 15x can be achieved when O(108) particles are computed on the GPU rather than the CPU cluster. Optimizations and limitations will be discussed, as will prospects for expanding to two- and four-way coupled systems. ONR Grant No. N00014-16-1-2472.

  13. High-speed data acquisition system application of LHC particles on the accelerator

    CERN Document Server

    Torres, J; González, V; Sanchis, E; Soret, J

    2003-01-01

    In data acquisition processes appropriate to large particle detectors, there is a key component for processing data in real time as an integral part of the hierarchic system of information filtering. It is a read out driver (ROD), responsible for data reception, reprocessing, routing and broadcasting to the next acquisition level. In order to implement a system with these features it is essential to count on advanced programmable logic devices that allow for all the information collected at high speed to be handled conveniently. In the European Laboratory for Particle Physics (CERN), the construction of a new particle accelerator, the Large Hadron Collider (LHC), is being completed. It is envisaged that in 2006 proton packets will collide with the production of energy approaching 14 TeV. For the study of basic questions in particle physics large detectors (ATLAS and CMS) were set up, capable of absorbing all the information generated by these collisions (50 TB/s). (5 refs).

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-10-15

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

  15. Particle-in-Cell Code BEAMPATH for Beam Dynamics Simulations in Linear Accelerators and Beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Batygin, Y.

    2004-10-28

    A code library BEAMPATH for 2 - dimensional and 3 - dimensional space charge dominated beam dynamics study in linear particle accelerators and beam transport lines is developed. The program is used for particle-in-cell simulation of axial-symmetric, quadrupole-symmetric and z-uniform beams in a channel containing RF gaps, radio-frequency quadrupoles, multipole lenses, solenoids and bending magnets. The programming method includes hierarchical program design using program-independent modules and a flexible combination of modules to provide the most effective version of the structure for every specific case of simulation. Numerical techniques as well as the results of beam dynamics studies are presented.

  16. Review of linear optics measurement and correction for charged particle accelerators

    Science.gov (United States)

    Tomás, Rogelio; Aiba, Masamitsu; Franchi, Andrea; Iriso, Ubaldo

    2017-05-01

    Measurement and correction of charged particle beam optics have been a major concern since the advent of strong focusing synchrotron accelerators. Traditionally, particle colliders have led the development of optics control based on turn-by-turn beam centroid measurements, while lepton storage rings have focused on closed-orbit-response matrix techniques. Recently, considerable efforts are being invested in comparing these techniques at different synchrotron radiation sources and colliders. An emerging class of less invasive techniques based on the optimization of performance-related observables is demonstrating a great potential. In this paper, a review of existing techniques is presented highlighting comparisons, relative merits and limitations.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-21

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

  18. Spatial Relationships of Auroral Particle Acceleration Relative to High Latitude Plasma Boundaries

    Science.gov (United States)

    Ghielmetti, Arthur G.

    1997-01-01

    This final report describes the activities under NASA contract to Lockheed Missiles and Space Company. It covers the period from 10-1-94 to 12-31-97. The objective of this investigation is to identify and characterize the spatial relationships of auroral particle acceleration features relative to the characteristic transition features in the surrounding polar ionospheric plasmas. Due to the reduced funding level approved for this contract, the original scope of the proposed work was readjusted with the focus placed on examining spatial relationships with respect to particle structures.

  19. Design of MgB2 superconducting dipole magnet for particle beam transport in accelerators

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.; Zangenberg, N.; Baurichter, A.

    2006-01-01

    . The existing markets of superconducting technology is within highly specialized scientific areas such as magnetic confinement in fusion energy, sample environment in neutron scattering and large scale acceleratorssuch as the Large Hadron Collider(LHC) at Cern, or in the nuclear magnetic resonance (NMR...... for the collaborating company Danfysik A/S, which has a strongtradition in building resistive magnets for particle accelerators[4]. A technology transfer project was formulated at the end of 2005 with the purpose to collect the knowledge about the MgB2 superconductor gained in the STVF program and in the European...... in a dipole magnet for guiding particle beams in a small scale accelerator is examined with the purpose to build lighter and smaller than the present resistive magnets. Here the criticalcurrent density of primarily MgB2 will be compared with current density determined by specifications similar to the Tevatron...

  20. Beam-Based Error Identification and Correction Methods for Particle Accelerators

    CERN Document Server

    AUTHOR|(SzGeCERN)692826; Tomas, Rogelio; Nilsson, Thomas

    2014-06-10

    Modern particle accelerators have tight tolerances on the acceptable deviation from their desired machine parameters. The control of the parameters is of crucial importance for safe machine operation and performance. This thesis focuses on beam-based methods and algorithms to identify and correct errors in particle accelerators. The optics measurements and corrections of the Large Hadron Collider (LHC), which resulted in an unprecedented low β-beat for a hadron collider is described. The transverse coupling is another parameter which is of importance to control. Improvement in the reconstruction of the coupling from turn-by-turn data has resulted in a significant decrease of the measurement uncertainty. An automatic coupling correction method, which is based on the injected beam oscillations, has been successfully used in normal operation of the LHC. Furthermore, a new method to measure and correct chromatic coupling that was applied to the LHC, is described. It resulted in a decrease of the chromatic coupli...

  1. Particle-in-cell simulations of plasma accelerators and electron-neutral collisions

    Directory of Open Access Journals (Sweden)

    David L. Bruhwiler

    2001-10-01

    Full Text Available We present 2D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low \\(∼10^{16} W/cm^{2}\\ and high \\(∼10^{18} W/cm^{2}\\ peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications to XOOPIC required by this work, and summarize the issues relevant to modeling relativistic electron-neutral collisions in a particle-in-cell code.

  2. Particle-in-cell simulations of plasma accelerators and electron-neutral collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bruhwiler, David L.; Giacone, Rodolfo E.; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, W.P.; Shadwick, B.A.

    2001-10-01

    We present 2-D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approx}10{sup 16} W/cm{sup 2}) and high ({approx}10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications of XOOPIC required by this work, and summarize the issues relevant to modeling relativistic electron-neutral collisions in a particle-in-cell code.

  3. openSE: a Systems Engineering Framework Particularly Suited to Particle Accelerator Studies and Development Projects

    Energy Technology Data Exchange (ETDEWEB)

    Bonnal, P. [CERN; Féral, B. [CERN; Kershaw, K. [CERN; Nicquevert, B. [CERN; Baudin, M. [Ecole Normale Superieure; Lari, L. [ESS, Lund; Le Cardinal, J. [Chatenay-Malabry, Ecole Centrale

    2016-07-15

    Particle accelerator projects share many characteristics with industrial projects. However, experience has shown that best practice of industrial project management is not always well suited to particle accelerator projects. Major differences include the number and complexity of technologies involved, the importance of collaborative work, development phases that can last more than a decade, and the importance of telerobotics and remote handling to address future preventive and corrective maintenance requirements due to induced radioactivity, to cite just a few. The openSE framework it is a systems engineering and project management framework specifically designed for scientific facilities’ systems and equipment studies and development projects. Best practices in project management, in systems and requirements engineering, in telerobotics and remote handling and in radiation safety management were used as sources of inspiration, together with analysis of current practices surveyed at CERN, GSI and ESS.

  4. 3-Component acceleration field measurement by dual-time stereoscopic particle image velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Perret, L. [Laboratoire d' Etudes Aerodynamiques - UMR CNRS 6609, Poitiers (France); Boulevard Paul Langevin, Laboratoire de Mecanique de Lille - UMR CNRS 8107, Villeneuve d' Ascq (France); Braud, P.; David, L. [Laboratoire d' Etudes Aerodynamiques - UMR CNRS 6609, Boulevard Marie et Pierre Curie teleport 2, B.P. 30179, Futuroscope Poitiers Cedex (France); Fourment, C.; Delville, J. [Laboratoire d' Etudes Aerodynamiques - UMR CNRS 6609, Poitiers (France)

    2006-05-15

    In this article, a multiplane stereo-particle image velocimetry (PIV) system was implemented and validated to measure the three-component acceleration field in a plane of turbulent flows. The employed technique relies on the use of two stereoscopic particle image velocimetry (SPIV) systems to measure pairs of velocity fields superimposed in space but shifted in time. The time delay between the two velocity fields enables the implementation of a finite difference scheme to compute temporal derivatives. The use of two synchronized SPIV systems allows us to overcome the limited acquisition rate of PIV systems when dealing with highly turbulent flows. Moreover, a methodology based on the analysis of the spectral error distribution is described here to determine the optimal time delay to compute time derivatives. The present dual-time SPIV arrangement and the proposed analysis method are applied to measure three-component acceleration fields in a cross section of a subsonic plane turbulent mixing layer. (orig.)

  5. 1999 Review of superconducting dipole and quadrupole magnets for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Devred, A. [CEA/Saclay, Dept. d' Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l' Instrumentation Associee (DAPNIA), 91 - Gif-sur-Yvette (France); CERN, Conseil Europeen pour la recherche nucleaire, Laboratoire europeen pour la physique des particules Geneve (Switzerland)

    1999-12-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron-type accelerator, 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 hundreds to several thousands) of 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 (section 1), we present a brief history of large superconducting particle accelerators, and we detail ongoing superconducting accelerator magnet R and D programs around the world (Section 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb3Sn), and we describe the manufacturing of NbTi wires and cables (section 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 presenting the complex formalism used to represent two-dimensional fields (section 4), and we discuss the two-dimensional current distributions that are the most appropriate for generating pure dipole and pure quadrupole fields (section 5). We explain how these ideal distributions can be approximated by so-called cos{theta} and cos{sup 2}{theta} coil designs and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that have been developed to restrain magnet coils and to ensure proper

  6. Proposed Few-optical Cycle Laser-driven ParticleAccelerator Structure

    Energy Technology Data Exchange (ETDEWEB)

    Plettner, T.; Lu, P.; Byer, R.L.; /Stanford U., Ginzton Lab.

    2006-10-06

    We describe a transparent dielectric grating accelerator structure that is designed for ultra-short laser pulse operation. The structure is based on the principle of periodic field reversal to achieve phase synchronicity for relativistic particles, however to preserve ultra-short pulse operation it does not resonate the laser field in the vacuum channel. The geometry of the structure appears well suited for application with high average power lasers and high thermal loading. Finally, it shows potential for an unloaded gradient of 10 GeV/m with 10 fsec laser pulses and the possibility to accelerate 10{sup 6} electrons per bunch at an efficiency of 8%. The fabrication procedure and a proposed near term experiment with this accelerator structure are presented.

  7. Monte Carlo simulations of ultra high vacuum and synchrotron radiation for particle accelerators

    CERN Document Server

    AUTHOR|(CDS)2082330; Leonid, Rivkin

    With preparation of Hi-Lumi LHC fully underway, and the FCC machines under study, accelerators will reach unprecedented energies and along with it very large amount of synchrotron radiation (SR). This will desorb photoelectrons and molecules from accelerator walls, which contribute to electron cloud buildup and increase the residual pressure - both effects reducing the beam lifetime. In current accelerators these two effects are among the principal limiting factors, therefore precise calculation of synchrotron radiation and pressure properties are very important, desirably in the early design phase. This PhD project shows the modernization and a major upgrade of two codes, Molflow and Synrad, originally written by R. Kersevan in the 1990s, which are based on the test-particle Monte Carlo method and allow ultra-high vacuum and synchrotron radiation calculations. The new versions contain new physics, and are built as an all-in-one package - available to the public. Existing vacuum calculation methods are overvi...

  8. A note on the theory of transverse diffusion in shock particle acceleration

    OpenAIRE

    Treumann, R. A.

    2008-01-01

    We investigate the role of the form of the spatial diffusion coefficient in shock acceleration of fast particles. Referring to non-classical diffusion and using the results of numerical (hybrid) simulations tailored for the downstream shock population in quasi-perpendicualr high-Mach number collisionless shocks to which we apply the theory, we demonstrate that the inferred diffusion coefficients are in excellent agreement with the requirements of the theory and its predictions. Diffusion in t...

  9. Particle acceleration by collisionless shocks containing large-scale magnetic-field variations

    OpenAIRE

    Guo, F.; Jokipii, J. R.; 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 p...

  10. Solid-State Powered X-band Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Mohamed A.K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nann, Emilio A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dolgashev, Valery A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tantawi, Sami [SLAC National Accelerator Lab., Menlo Park, CA (United States); Neilson, Jeff [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2017-03-06

    In this report we disseminate the hot test results of an X-band 100-W solid state amplifier chain for linear accelerator (linac) applications. Solid state power amplifiers have become increasingly attractive solutions for achieving high power in radar and maritime applications. Here the performance of solid state amplifiers when driving an RF cavity is investigated. Commercially available, matched and fully-packaged GaN on SiC HEMTs are utilized, comprising a wideband driver stage and two power stages. The amplifier chain has a high poweradded- efficiency and is able to supply up to ~1.2 MV/m field gradient at 9.2 GHz in a simple test cavity, with a peak power exceeding 100 W. These findings set forth the enabling technology for solid-state powered linacs.

  11. Radiation from accelerated particles in relativistic jets with shocks, shear-flow, and reconnection

    Directory of Open Access Journals (Sweden)

    Nishikawa K.-I.

    2013-12-01

    Full Text Available We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma for electron-positron and electron-ion plasmas. Strong magnetic fields generated in the trailing jet shock lead to transverse deflection and acceleration of the electrons. We have self-consistently calculated the radiation from the electrons accelerated in the turbulent magnetic fields for different jet Lorentz factors. We find that the synthetic spectra depend on the bulk Lorentz factor of the jet, the jet temperature, and the strength of the magnetic fields generated in the shock. We have investigated the generation of magnetic fields associated with velocity shear between an unmagnetized relativistic (core jet and an unmagnetized sheath plasma. We discuss particle acceleration in collimation shocks for AGN jets formed by relativistic MHD simulations. Our calculated spectra should lead to a better understanding of the complex time evolution and/or spectral structure from gamma-ray bursts, relativistic jets, and supernova remnants.

  12. The Northern Rims of SNR RCW 86 Chandras Recent Observations and their Implications for Particle Acceleration

    Science.gov (United States)

    Castro, Daniel

    2018-01-01

    The Chandra observations towards the northwest (NW) and northeast (NE) rims of supernova remnant (SNR) RCW 86 reveal great detail about the characteristics of the shocks, particle acceleration and the local environments in these 2 distinct regions. Both the NW and NE of RCW 86 show clear evidence of non-thermal X-ray emission, identified as synchrotron radiation from shock-accelerated electrons with TeV energies, interacting with the compressed, and probably amplified, local magnetic field.Magnetic field amplification (MFA) is broadly believed to result from, and contribute to, cosmic ray acceleration at the shocks of SNRs. However, we still lack a detailed understanding of the particle acceleration mechanism, and with this study we address the connection between the shock properties and ambient medium with MFA. The Chandra observations of RCW 86 allowed us to constrain the magnitude of the post- shock magnetic field in the NE and NW rims by deriving synchrotron filament widths, and also the densities in these regions, using thermal emission co-located with the non-thermal rims. I will discuss our analysis in detail and comment on how MFA appears to be related to certain characteristics of the SNR shock.

  13. The Northern Rims of SNR RCW 86 - Chandra's Recent Observations and their Implications for Particle Acceleration

    Science.gov (United States)

    Castro, Daniel

    2017-08-01

    The Chandra observations towards the northwest (NW) and northeast (NE) rims of supernova remnant (SNR) RCW 86 reveal great detail about the characteristics of the shocks, particle acceleration and the local environments in these 2 distinct regions. Both the NW and NE of RCW 86 show clear evidence of non-thermal X-ray emission, identified as synchrotron radiation from shock-accelerated electrons with TeV energies, interacting with the compressed, and probably amplified, local magnetic field. Magnetic field amplification (MFA) is broadly believed to result from, and contribute to, cosmic ray acceleration at the shocks of SNRs. However, we still lack a detailed understanding of the particle acceleration mechanism, and with this study we address the connection between the shock properties and ambient medium with MFA. The Chandra observations of RCW 86 allowed us to constrain the magnitude of the post-shock magnetic field in the NE and NW rims by deriving synchrotron filament widths, and also the densities in these regions, using thermal emission co-located with the non-thermal rims. I will discuss our analysis in detail and comment on how MFA appears to be related to certain characteristics of the SNR shock.

  14. Acceleration, Transport, Forecasting and Impact of solar energetic particles in the framework of the 'HESPERIA' HORIZON 2020 project

    Science.gov (United States)

    Malandraki, Olga; Klein, Karl-Ludwig; Vainio, Rami; Agueda, Neus; Nunez, Marlon; Heber, Bernd; Buetikofer, Rolf; Sarlanis, Christos; Crosby, Norma

    2017-04-01

    High-energy solar energetic particles (SEPs) emitted from the Sun are a major space weather hazard motivating the development of predictive capabilities. In this work, the current state of knowledge on the origin and forecasting of SEP events will be reviewed. Subsequently, we will present the EU HORIZON2020 HESPERIA (High Energy Solar Particle Events foRecastIng and Analysis) project, its structure, its main scientific objectives and forecasting operational tools, as well as the added value to SEP research both from the observational as well as the SEP modelling perspective. The project addresses through multi-frequency observations and simulations the chain of processes from particle acceleration in the corona, particle transport in the magnetically complex corona and interplanetary space to the detection near 1 AU. Furthermore, publicly available software to invert neutron monitor observations of relativistic SEPs to physical parameters that can be compared with space-borne measurements at lower energies is provided for the first time by HESPERIA. In order to achieve these goals, HESPERIA is exploiting already available large datasets stored in databases such as the neutron monitor database (NMDB) and SEPServer that were developed under EU FP7 projects from 2008 to 2013. Forecasting results of the two novel SEP operational forecasting tools published via the consortium server of 'HESPERIA' will be presented, as well as some scientific key results on the acceleration, transport and impact on Earth of high-energy particles. Acknowledgement: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.

  15. INVESTIGATING PARTICLE ACCELERATION IN PROTOSTELLAR JETS: THE TRIPLE RADIO CONTINUUM SOURCE IN SERPENS

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Kamenetzky, Adriana; Valotto, Carlos [Instituto de Astronomía Teórica y Experimental, (IATE-UNC), X5000BGR Córdoba (Argentina); Carrasco-González, Carlos; Rodríguez, Luis F. [Instituto de Radioastronomía y Astrofísica (IRyA-UNAM), 58089 Morelia, México (Mexico); Araudo, Anabella [University of Oxford, Astrophysics, Keble Road, Oxford OX1 3RH (United Kingdom); Torrelles, José M. [Institut de Ciències de l’Espai (CSIC-IEEC) and Institut de Ciències del Cosmos (UB-IEEC), Martí i Franquès 1, E-08028 Barcelona (Spain); Anglada, Guillem [Instituto de Astrofísica de Andalucía, CSIC, Camino Bajo de Huétor 50, E-18008 Granada (Spain); Martí, Josep [Dept. de Física, EPS de Jaén, Universidad de Jaén, Campus Las Lagunillas s/n, A3-402, E-23071 Jaén (Spain)

    2016-02-10

    While most protostellar jets present free–free emission at radio wavelengths, synchrotron emission has also been proposed to be present in a handful of these objects. The presence of nonthermal emission has been inferred by negative spectral indices at centimeter wavelengths. In one case (the HH 80-81 jet arising from a massive protostar), its synchrotron nature was confirmed by the detection of linearly polarized radio emission. One of the main consequences of these results is that synchrotron emission implies the presence of relativistic particles among the nonrelativistic material of these jets. Therefore, an acceleration mechanism should be taking place. The most probable scenario is that particles are accelerated when the jets strongly impact against the dense envelope surrounding the protostar. Here we present an analysis of radio observations obtained with the Very Large Array of the triple radio source in the Serpens star-forming region. This object is known to be a radio jet arising from an intermediate-mass protostar. It is also one of the first protostellar jets where the presence of nonthermal emission was proposed. We analyze the dynamics of the jet and the nature of the emission and discuss these issues in the context of the physical parameters of the jet and the particle acceleration phenomenon.

  16. Simulations and measurements of coupling impedance for modern particle accelerator devices

    CERN Document Server

    AUTHOR|(CDS)2158523; Biancacci, Nicolò; Mostacci, Andrea

    In this document it has been treated the study of the coupling impedance in modern devices, already installed or not, in different particle accelerators. In the specific case: • For a device in-phase of project, several simulations for impedance calculation have been done. • For a component already realized and used, measurements of coupling impedance value have been done. Simulations are used to determine the impact of the interconnect between to magnets, designed for the future particle accelerator FCC, on the overall impedance of the machine which is about 100 km long. In particular has been done a check between theory, simulations and measurements of components already built, allowing a better and deeper study of the component we have analysed. Controls that probably will be helpful to have a clear guideline in future works. The measurements instead concern in an existing component that was already used in LHC, the longest particle accelerator ever realised on the planet, 27 km long. The coupling impe...

  17. Particle accelerators, colliders, and the story of high energy physics charming the cosmic snake

    CERN Document Server

    Jayakumar, Raghavan

    2012-01-01

    The Nordic mythological Cosmic Serpent, Ouroboros, is said to be coiled in the depths of the sea, surrounding the Earth with its tail in its mouth. In physics, this snake is a metaphor for the Universe, where the head, symbolizing the largest entity – the Cosmos – is one with the tail, symbolizing the smallest – the fundamental particle. Particle accelerators, colliders and detectors are built by physicists and engineers to uncover the nature of the Universe while discovering its building blocks. “Charming the Cosmic Snake” takes the readers through the science behind these experimental machines: the physics principles that each stage of the development of particle accelerators helped to reveal, and the particles they helped to discover. The book culminates with a description of the Large Hadron Collider, one of the world’s largest and most complex machines operating in a 27-km circumference tunnel near Geneva. That collider may prove or disprove many of our basic theories about the nature of matt...

  18. On the compressibility effect in test particle acceleration by magnetohydrodynamic turbulence

    CERN Document Server

    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...

  19. Blind Quantum Signature with Controlled Four-Particle Cluster States

    Science.gov (United States)

    Li, Wei; Shi, Jinjing; Shi, Ronghua; Guo, Ying

    2017-08-01

    A novel blind quantum signature scheme based on cluster states is introduced. Cluster states are a type of multi-qubit entangled states and it is more immune to decoherence than other entangled states. The controlled four-particle cluster states are created by acting controlled-Z gate on particles of four-particle cluster states. The presented scheme utilizes the above entangled states and simplifies the measurement basis to generate and verify the signature. Security analysis demonstrates that the scheme is unconditional secure. It can be employed to E-commerce systems in quantum scenario.

  20. On the Accelerated Settling of Fine Particles in a Bidisperse Slurry

    Directory of Open Access Journals (Sweden)

    Leonid L. Minkov

    2015-01-01

    Full Text Available An estimation of increasing the volume average sedimentation velocity of fine particles in bidisperse suspension due to their capturing in the circulation zone formed in the laminar flow of incompressible viscous fluid around the spherical coarse particle is proposed. The estimation is important for an explanation of the nonmonotonic shape of the separation curve observed for hydrocyclones. The volume average sedimentation velocity is evaluated on the basis of a cellular model. The characteristic dimensions of the circulation zone are obtained on the basis of a numerical solution of Navier-Stokes equations. Furthermore, these calculations are used for modelling the fast sedimentation of fine particles during their cosedimentation in bidisperse suspension. It was found that the acceleration of sedimentation of fine particles is determined by the concentration of coarse particles in bidisperse suspension, and the sedimentation velocity of fine fraction is proportional to the square of the coarse and fine particle diameter ratio. The limitations of the proposed model are ascertained.

  1. Particle Identification on an FPGA Accelerated Compute Platform for the LHCb Upgrade

    Science.gov (United States)

    Fäerber, Christian; Schwemmer, Rainer; Machen, Jonathan; Neufeld, Niko

    2017-07-01

    The current LHCb readout system will be upgraded in 2018 to a “triggerless” readout of the entire detector at the Large Hadron Collider collision rate of 40 MHz. The corresponding bandwidth from the detector down to the foreseen dedicated computing farm (event filter farm), which acts as the trigger, has to be increased by a factor of almost 100 from currently 500 Gb/s up to 40 Tb/s. The event filter farm will preanalyze the data and will select the events on an event by event basis. This will reduce the bandwidth down to a manageable size to write the interesting physics data to tape. The design of such a system is a challenging task, and the reason why different new technologies are considered and have to be investigated for the different parts of the system. For the usage in the event building farm or in the event filter farm (trigger), an experimental field programmable gate array (FPGA) accelerated computing platform is considered and, therefore, tested. FPGA compute accelerators are used more and more in standard servers such as for Microsoft Bing search or Baidu search. The platform we use hosts a general Intel CPU and a high-performance FPGA linked via the high-speed Intel QuickPath Interconnect. An accelerator is implemented on the FPGA. It is very likely that these platforms, which are built, in general, for high-performance computing, are also very interesting for the high-energy physics community. First, the performance results of smaller test cases performed at the beginning are presented. Afterward, a part of the existing LHCb RICH particle identification is tested and is ported to the experimental FPGA accelerated platform. We have compared the performance of the LHCb RICH particle identification running on a normal CPU with the performance of the same algorithm, which is running on the Xeon-FPGA compute accelerator platform.

  2. Nonthermal Particle Acceleration in 3D Relativistic Magnetic Reconnection in Pair Plasma

    Science.gov (United States)

    Werner, Gregory R.; Uzdensky, Dmitri A.

    2017-07-01

    As a fundamental process converting magnetic to plasma energy in high-energy astrophysical plasmas, relativistic magnetic reconnection is a leading explanation for the acceleration of particles to the ultrarelativistic energies that are necessary to power nonthermal emission (especially X-rays and gamma-rays) in pulsar magnetospheres and pulsar wind nebulae, coronae and jets of accreting black holes, and gamma-ray bursts. An important objective of plasma astrophysics is therefore the characterization of nonthermal particle acceleration (NTPA) effected by reconnection. Reconnection-powered NTPA has been demonstrated over a wide range of physical conditions using large 2D kinetic simulations. However, its robustness in realistic 3D reconnection—in particular, whether the 3D relativistic drift-kink instability (RDKI) disrupts NTPA—has not been systematically investigated, although pioneering 3D simulations have observed NTPA in isolated cases. Here, we present the first comprehensive study of NTPA in 3D relativistic reconnection in collisionless electron-positron plasmas, characterizing NTPA as the strength of 3D effects is varied systematically via the length in the third dimension and the strength of the guide magnetic field. We find that, while the RDKI prominently perturbs 3D reconnecting current sheets, it does not suppress particle acceleration, even for zero guide field; fully 3D reconnection robustly and efficiently produces nonthermal power-law particle spectra closely resembling those obtained in 2D. This finding provides strong support for reconnection as the key mechanism powering high-energy flares in various astrophysical systems. We also show that strong guide fields significantly inhibit NTPA, slowing reconnection and limiting the energy available for plasma energization, yielding steeper and shorter power-law spectra.

  3. CERN Library | Ted Wilson presents "Engines of discovery: a century of particle accelerators" (revised and expanded edition) | 22 July

    CERN Multimedia

    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.   Engines of discovery: a century of particle accelerators (revised and expanded edition), by Andrew Sessler and Ted Wilson, World Scientific, 2014, ISBN 9789814417198. An earlier book by the same authors, Engines of Discovery: A Century of Particle Accelerators, chronicled the development of these large accelerators and colliders, emphasising 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 attit...

  4. Novel methods in the Particle-In-Cell accelerator Code-Framework Warp

    Energy Technology Data Exchange (ETDEWEB)

    Vay, J-L [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Grote, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cohen, R. H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Friedman, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2012-12-26

    The Particle-In-Cell (PIC) Code-Framework Warp is being developed by the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) to guide the development of accelerators that can deliver beams suitable for high-energy density experiments and implosion of inertial fusion capsules. It is also applied in various areas outside the Heavy Ion Fusion program to the study and design of existing and next-generation high-energy accelerators, including the study of electron cloud effects and laser wakefield acceleration for example. This study presents an overview of Warp's capabilities, summarizing recent original numerical methods that were developed by the HIFS-VNL (including PIC with adaptive mesh refinement, a large-timestep 'drift-Lorentz' mover for arbitrarily magnetized species, a relativistic Lorentz invariant leapfrog particle pusher, simulations in Lorentz-boosted frames, an electromagnetic solver with tunable numerical dispersion and efficient stride-based digital filtering), with special emphasis on the description of the mesh refinement capability. In addition, selected examples of the applications of the methods to the abovementioned fields are given.

  5. Review of Heavy-ion Induced Desorption Studies for Particle Accelerators

    CERN Document Server

    Mahner, E

    2008-01-01

    During high-intensity heavy-ion operation of several particle accelerators worldwide, large dynamic pressure rises of orders of magnitude were caused by lost beam ions that impacted under grazing angle onto the vacuum chamber walls. This ion-induced desorption, observed, for example, at CERN, GSI, and BNL, can seriously limit the ion intensity, luminosity, and beam lifetime of the accelerator. For the heavyion program at CERN's Large Hadron Collider collisions between beams of fully stripped lead (208Pb82+) ions with a beam energy of 2.76 TeV/u and a nominal luminosity of 10**27 cm**-2 s**-1 are foreseen. The GSI future project FAIR (Facility for Antiproton and Ion Research) aims at a beam intensity of 10**12 uranium (238U28+) ions per second to be extracted from the synchrotron SIS18. Over the past years an experimental effort has been made to study the observed dynamic vacuum degradations, which are important to understand and overcome for present and future particle accelerators. The paper reviews the resu...

  6. Metal forming technology for the fabrication of seamless Superconducting radiofrequency cavities for particle accelerators

    Directory of Open Access Journals (Sweden)

    Palmieri Vincenzo

    2015-01-01

    Full Text Available The world of Particle accelerators is rather unique, since in a few high-energy Physics great laboratories, such at CERN for example, there have been built the largest technological installations ever conceived by humankind. The Radiofrequency resonant cavities are the pulsing heart of an accelerator. In case of superconducting accelerators, bulk niobium cavities, able to perform accelerating gradients up to 40 MeV/m, are just a jewel of modern technology. The standard fabrication technology foresees the cutting of circular blanks, their deep-drawing into half-cells, and its further joining by electron beam welding under ultra high vacuum environment that takes several hours. However, proposals such as the International Linear Collider, to which more than 900 scientists from all over the world participate, foresee the installation of 20.000 cavities. In numbers, it means the electron beam weld one by one under Ultra High Vacuum of 360,000 hemi-cells. At a cost of 500 €/Kg of high purity Niobium, this will mean a couple of hundreds of millions of Euros only for the bare material. In this panorama it is evident that a cost reducing approach must be considered. In alternative the author has proposed a seamless and low cost fabrication method based on spinning of fully resonators. Preliminary RF tests at low temperatures have proved that high accelerating gradients are achievable and that they are not worse than those obtainable with the standard technology. Nevertheless up to when the next accelerator will be decided to be built there is still room for improvement.

  7. CERN Technical Training 2003: Learning for the LHC! : AXEL-2003  -  Introduction to Particle Accelerators

    CERN Multimedia

    2003-01-01

    AXEL-2003 is a course given at CERN within the framework of the Technical Training Programme. The course will present an introduction to particle accelerators. Known in the past as the PS Complex Operation Course (or the "PS Shutdown Course"), and organised by the ex-PS division until last year, it is now organised as a joint venture between the AB division and Technical Training, and open to a wider CERN community. The AXEL-2003 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 and the course supports will be in English, with questions and answers also in French. Lectures will be recorded and available online via the Web Lectu...

  8. Energy Effciency of Particle Accelerators - A Networking Effort within the EUCARD2 Program

    CERN Document Server

    Stadlmann, J; Gehring, R; Jensen, E; Parker, T; Seidel, M

    2014-01-01

    EuCARD is an Integrating Activity Project for coordinated Research and Development on Particle Accelerators, co-funded by the European Commission under the FP7 Capacities Programme. Within the network EnEfficient [1] we address topics around energy efficiency of research accelerators. The ambitious scientific research goals of modern accelerator facilities lead to high requirements in beam power and beam quality for those research accelerators. In conjunction with the user’s needs the power consumption and environmental impact of the research facilities becomes a major factor in the perception of both funding agencies and the general public. In this Network we combine and focus the R&D done individually at different research centers into a series of workshops. We cover the topics “Energy recovery from cooling circuits “, “Higher electronic efficiency RF power generation“, “Short term energy storage systems”, “Virtual power plants” and “Beam transfer channels with low power consumption�...

  9. Facing new safety-challenges in a large particle accelerator experiment at CERN

    CERN Document Server

    Schmidt, R

    1998-01-01

    Particle accelerators and the detectors for the observation of beam- collisions are becoming larger and/or more powerful, as well as more international as to resources in financing and sharing in research. The Compact Muon Solenoid (CMS) at the European Laboratory for Particle Physics (CERN) in Geneva is such a modern instrument. The Compact Muon Solenoid (CMS) is one of the two new large detectors which will be installed as part of the Large Hadron Collider (LHC) at the European Laboratory for Particle Physics (CERN) in Geneva, Switzerland. The LHC will be the worlds most powerful experimental facility of this type, for planned operation by the year 2005. The machine, mainly to be operated as a proton-proton collider will produce fluencies (luminosities in accelerator language) of 10 E+34 /cm2.sec, beam energies of 7 TeV and will use magnetic fields of up to 8.3 T in the bending magnets and around 4 T in the spectrometric magnets of the large detectors. (0 refs).

  10. Disk-accreting magnetic neutron stars as high-energy particle accelerators

    Science.gov (United States)

    Hamilton, Russell J.; Lamb, Frederick K.; Miller, M. Coleman

    1994-01-01

    Interaction of an accretion disk with the magnetic field of a neutron star produces large electromotive forces, which drive large conduction currents in the disk-magnetosphere-star circuit. Here we argue that such large conduction currents will cause microscopic and macroscopic instabilities in the magnetosphere. If the minimum plasma density in the magnetosphere is relatively low is less than or aproximately 10(exp 9)/cu cm, current-driven micro-instabilities may cause relativistic double layers to form, producing voltage differences in excess of 10(exp 12) V and accelerating charged particles to very high energies. If instead the plasma density is higher (is greater than or approximately = 10(exp 9)/cu cm, twisting of the stellar magnetic field is likely to cause magnetic field reconnection. This reconnection will be relativistic, accelerating plasma in the magnetosphere to relativistic speeds and a small fraction of particles to very high energies. Interaction of these high-energy particles with X-rays, gamma-rays, and accreting plasma may produce detectable high-energy radiation.

  11. Design of Linear Accelerator (LINAC) tanks for proton therapy via Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) approaches

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, T.; De Palma, L.; Laneve, D.; Strippoli, V.; Cuccovilllo, A.; Prudenzano, F. [Electrical and Information Engineering Department (DEI), Polytechnic Institute of Bari, 4 Orabona Street, CAP 70125, Bari, (Italy); Dimiccoli, V.; Losito, O.; Prisco, R. [ITEL Telecomunicazioni, 39 Labriola Street, CAP 70037, Ruvo di Puglia, Bari, (Italy)

    2015-07-01

    A homemade computer code for designing a Side- Coupled Linear Accelerator (SCL) is written. It integrates a simplified model of SCL tanks with the Particle Swarm Optimization (PSO) algorithm. The computer code main aim is to obtain useful guidelines for the design of Linear Accelerator (LINAC) resonant cavities. The design procedure, assisted via the aforesaid approach seems very promising, allowing future improvements towards the optimization of actual accelerating geometries. (authors)

  12. Proceedings of the 22nd Particle Accelerator Conference (PAC'07)

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    2007-08-01

    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.

  13. Multiphysics Analysis of Frequency Detuning in Superconducting RF Cavities for Proton Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Awida, M. H. [Fermilab; Gonin, I. [Fermilab; Passarelli, D. [Fermilab; Sukanov, A. [Fermilab; Khabiboulline, T. [Fermilab; Yakovlev, V. [Fermilab

    2016-01-22

    Multiphysics analyses for superconducting cavities are essential in the course of cavity design to meet stringent requirements on cavity frequency detuning. Superconducting RF cavities are the core accelerating elements in modern particle accelerators whether it is proton or electron machine, as they offer extremely high quality factors thus reducing the RF losses per cavity. However, the superior quality factor comes with the challenge of controlling the resonance frequency of the cavity within few tens of hertz bandwidth. In this paper, we investigate how the multiphysics analysis plays a major role in proactively minimizing sources of frequency detuning, specifically; microphonics and Lorentz Force Detuning (LFD) in the stage of RF design of the cavity and mechanical design of the niobium shell and the helium vessel.

  14. First Steps Toward Incorporating Image Based Diagnostics Into Particle Accelerator Control Systems Using Convolutional Neural Networks

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, A. L.; Biedron, S. G.; Milton, S. V.; Edelen, J. P.

    2016-12-16

    At present, a variety of image-based diagnostics are used in particle accelerator systems. Often times, these are viewed by a human operator who then makes appropriate adjustments to the machine. Given recent advances in using convolutional neural networks (CNNs) for image processing, it should be possible to use image diagnostics directly in control routines (NN-based or otherwise). This is especially appealing for non-intercepting diagnostics that could run continuously during beam operation. Here, we show results of a first step toward implementing such a controller: our trained CNN can predict multiple simulated downstream beam parameters at the Fermilab Accelerator Science and Technology (FAST) facility's low energy beamline using simulated virtual cathode laser images, gun phases, and solenoid strengths.

  15. Interactive Visual Intervention Planning: Interactive Visualization for Intervention Planning in Particle Accelerator Environments with Ionizing Radiation

    CERN Document Server

    Fabry, Thomas; Feral, Bruno

    2013-01-01

    Intervention planning is crucial for maintenance operations in particle accelerator environments with ionizing radiation, during which the radiation dose contracted by maintenance workers should be reduced to a minimum. In this context, we discuss the visualization aspects of a new software tool, which integrates interactive exploration of a scene depicting an accelerator facility augmented with residual radiation level simulations, with the visualization of intervention data such as the followed trajectory and maintenance tasks. The visualization of each of these aspects has its effect on the final predicted contracted radiation dose. In this context, we explore the possible benefits of a user study, with the goal of enhancing the visual conditions in which the intervention planner using the software tool is minimizing the radiation dose.

  16. Kinetic modeling of particle acceleration in a solar null point reconnection region

    DEFF Research Database (Denmark)

    Baumann, Gisela; Haugbølle, Troels; Nordlund, Åke

    2013-01-01

    The primary focus of this paper is on the particle acceleration mechanism in solar coronal 3D reconnection null-point regions. Starting from a potential field extrapolation of a SOHO magnetogram taken on 2002 November 16, we first performed MHD simulations with horizontal motions observed by SOHO......-relativistic electron acceleration is mainly driven by a systematic electric field in the current sheet. A non-thermal population of electrons with a power-law distribution in energy forms, featuring a power-law index of about -1.75. This work provides a first step towards bridging the gap between macroscopic scales...... on the order of hundreds of Mm and kinetic scales on the order of cm in the solar corona, and explains how to achieve such a cross-scale coupling by utilizing either physical modifications or (equivalent) modifications of the constants of nature. With their exceptionally high resolution --- up to 135 billion...

  17. Solar Energetic Particle Acceleration by a Shock Wave Accompanying a Coronal Mass Ejection in the Solar Atmosphere

    Science.gov (United States)

    Petukhova, A. S.; Petukhov, I. S.; Petukhov, S. I.; Ksenofontov, L. T.

    2017-02-01

    Solar energetic particle acceleration by a shock wave accompanying a coronal mass ejection (CME) is studied. The description of the accelerated particle spectrum evolution is based on the numerical calculation of the diffusive transport equation with a set of realistic parameters. The relation between the CME and shock speeds, which depend on the initial CME radius, is determined. Depending on the initial CME radius, its speed, and the magnetic energy of the scattering Alfvén waves, the accelerated particle spectrum is established 10-60 minutes from the beginning of CME motion. The maximum energies of particles reach 0.1-10 GeV. The CME radii of 3-5 {R}⊙ and the shock radii of 5-10 {R}⊙ agree with observations. The calculated particle spectra agree with the observed ones in events registered by ground-based detectors if the turbulence spectrum in the solar corona significantly differs from the Kolmogorov one.

  18. Plasma Processing of SRF Cavities for the next Generation Of Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Vuskovic, Leposava

    2015-11-23

    The cost-effective production of high frequency accelerating fields are the foundation for the next generation of particle accelerators. The Ar/Cl2 plasma etching technology holds the promise to yield a major reduction in cavity preparation costs. Plasma-based dry niobium surface treatment provides an excellent opportunity to remove bulk niobium, eliminate surface imperfections, increase cavity quality factor, and bring accelerating fields to higher levels. At the same time, the developed technology will be more environmentally friendly than the hydrogen fluoride-based wet etching technology. Plasma etching of inner surfaces of standard multi-cell SRF cavities is the main goal of this research in order to eliminate contaminants, including niobium oxides, in the penetration depth region. Successful plasma processing of multi-cell cavities will establish this method as a viable technique in the quest for more efficient components of next generation particle accelerators. In this project the single-cell pill box cavity plasma etching system is developed and etching conditions are determined. An actual single cell SRF cavity (1497 MHz) is plasma etched based on the pill box cavity results. The first RF test of this plasma etched cavity at cryogenic temperature is obtained. The system can also be used for other surface modifications, including tailoring niobium surface properties, surface passivation or nitriding for better performance of SRF cavities. The results of this plasma processing technology may be applied to most of the current SRF cavity fabrication projects. In the course of this project it has been demonstrated that a capacitively coupled radio-frequency discharge can be successfully used for etching curved niobium surfaces, in particular the inner walls of SRF cavities. The results could also be applicable to the inner or concave surfaces of any 3D structure other than an SRF cavity.

  19. Non-thermal particle acceleration in collisionless relativistic electron-proton reconnection

    Science.gov (United States)

    Werner, G. R.; Uzdensky, D. A.; Begelman, M. C.; Cerutti, B.; Nalewajko, K.

    2018-02-01

    Magnetic reconnection in relativistic collisionless plasmas can accelerate particles and power high-energy emission in various astrophysical systems. Whereas most previous studies focused on relativistic reconnection in pair plasmas, less attention has been paid to electron-ion plasma reconnection, expected in black hole accretion flows and relativistic jets. We report a comprehensive particle-in-cell numerical investigation of reconnection in an electron-ion plasma, spanning a wide range of ambient ion magnetizations σi, from the semirelativistic regime (ultrarelativistic electrons but non-relativistic ions, 10-3 ≪ σi ≪ 1) to the fully relativistic regime (both species are ultrarelativistic, σi ≫ 1). We investigate how the reconnection rate, electron and ion plasma flows, electric and magnetic field structures, electron/ion energy partitioning, and non-thermal particle acceleration depend on σi. Our key findings are: (1) the reconnection rate is about 0.1 of the Alfvénic rate across all regimes; (2) electrons can form concentrated moderately relativistic outflows even in the semirelativistic, small-σi regime; (3) while the released magnetic energy is partitioned equally between electrons and ions in the ultrarelativistic limit, the electron energy fraction declines gradually with decreased σi and asymptotes to about 0.25 in the semirelativistic regime; and (4) reconnection leads to efficient non-thermal electron acceleration with a σi-dependent power-law index, p(σ _i)˜eq const+0.7σ _i^{-1/2}. These findings are important for understanding black hole systems and lend support to semirelativistic reconnection models for powering non-thermal emission in blazar jets, offering a natural explanation for the spectral indices observed in these systems.

  20. Improving the design and analysis of superconducting magnets for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ramesh Chandra [Univ. of Rajasthan, Jaipur (India). Dept. of Physics

    1996-11-01

    High energy particle accelerators are now the primary means of discovering the basic building blocks of matter and understanding the forces between them. In order to minimize the cost of building these machines, superconducting magnets are used in essentially all present day high energy proton and heavy ion colliders. The cost of superconducting magnets is typically in the range of 20--30% of the total cost of building such machines. The circulating particle beam goes through these magnets a large number of times (over hundreds of millions). The luminosity performance and life time of the beam in these machines depends significantly on the field quality in these magnets. Therefore, even a small error in the magnetic field shape may create a large cumulative effect in the beam trajectory to throw the particles of the magnet aperture. The superconducting accelerator magnets must, therefore, be designed and constructed so that these errors are small. In this thesis the research and development work will be described 3which has resulted in significant improvements in the field quality of the superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). The design and the field quality improvements in the prototype of the main collider dipole magnet for the Superconducting Super Collider (SSC) will also be presented. RHIC will accelerate and collide two counter rotating beams of heavy ions up to 100 GeV/u and protons up to 250 GeV. It is expected that RHIC will create a hot, dense quark-gluon plasma and the conditions which, according to the Big Bang theory, existed in the early universe.

  1. The extent of non-thermal particle acceleration in relativistic, electron-positron reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Greg [University of Colorado; Guo, Fan [Los Alamos National Laboratory

    2015-07-21

    Reconnection is studied as an explanation for high-energy flares from the Crab Nebula. The production of synchrotron emission >100 MeV challenges classical models of acceleration. 3D simulation shows that reconnection, converting magnetic energy to kinetic energy, can accelerate beyond γrad. The power-law index and high-energy cutoff are important for understanding the radiation spectrum dN/dγ = f(γ) ∝ γ. α and cutoff were measured vs. L and σ, where L is system (simulation) size and σ is upstream magnetization (σ = B2/4πnmc2). α can affect the high-energy cutoff. In conclusion, for collisionless relativistic reconnection in electron-positron plasma, without guide field, nb/nd=0.1: (1) relativistic magnetic reconnection yields power-law particle spectra, (2) the power law index decreases as σ increases, approaching ≈1.2. (3) the power law is cut off at an energy related to acceleration within a single current layer, which is proportional to the current layer length (for small systems, that length is the system length, yielding γc2 ≈ 0.1 L/ρ0; for large systems, the layer length is limited by secondary tearing instability, yielding γc1 ≈ 4σ; the transition from small to large is around L/ρ0 = 40σ.). (4) although the large-system energy cutoff is proportional to the average energy per particle, it is significantly higher than the average energy per particle.

  2. Final state multiplicity and particle correlation in small systems

    CERN Document Server

    Mariani, Valentina

    2017-01-01

    Final state variables and particle correlation will be discussed under a Multiple Parton Interaction (MPI) interpretation. The state of the art about the latest results on such variables will be provided. Furthermore the role played by event multiplicity in the deep understanding of particle correlation, in particular concerning the new results on the Long-Range Near Side two particle correlations by the CMS Collaboration, will bediscussed.

  3. Heisenberg-limited Sagnac Interferometer with Multi-particle States

    OpenAIRE

    Luo, Chengyi; Huang, Jiahao; Zhang, Xiangdong; Lee, Chaohong

    2016-01-01

    The Sagnac interferometry has been widely used to measure rotation frequency. Beyond the conventional single-particle Sagnac interferometry, we propose an atomic Sagnac interferometry via multi-particle entangled states. In our scheme, an ensemble of entangled two-state Bose atoms are moved in a ring by a state-dependent rotating potential and then are recombined for interference via Ramsey pulses after a specific time determined by the state-dependent rotating potential. The ultimate rotatio...

  4. Development of ultrahigh vacuum technology for particle accelerators and magnetic fusion devices

    CERN Document Server

    Dyll, A

    1994-01-01

    The development of ultrahigh vacuum technology for high-energy particle accelerators and magnetic fusion devices provided essential contributions to the progress in these two scientific endeavors over the last four decades. Storage rings were first proposed as an efficient means of producing intense high-energy particle beams by G. K. O'Neill in 1956. The milestone demonstrations of the importance of this invention came with the operation of the ISR device at CERN in 1971, a 2 km long vacuum vessel which operated at 10 sup - sup 1 sup 2 Torr and the SPEAR electron-positron collider at Stanford in 1972. These achievements required development of new materials, materials processing techniques, vacuum components, and vacuum instrumentation. UHV development continues through the present design efforts for the 27 km LHC ring at CERN, and numerous high intensity synchrotron light sources worldwide. A similar progression in UHV development preceded the operation of the present generation of large tokamaks built to d...

  5. Vortex Formation in a Shock-Accelerated Gas Induced by Particle Seeding

    Science.gov (United States)

    Vorobieff, Peter; Anderson, Michael; Conroy, Joseph; White, Ross; Truman, C. Randall; Kumar, Sanjay

    2011-05-01

    An instability forms in gas of constant density (air) with an initial nonuniform seeding of small particles or droplets as a planar shock wave passes through the two-phase medium. The seeding nonuniformity is produced by vertical injection of a slow-moving jet of air premixed with glycol droplets or smoke particles into the test section of a shock tube, with the plane of the shock parallel to the axis of the jet. After the shock passage, two counterrotating vortices form in the plane normal to that axis. The physical mechanism of the instability we observe is peculiar to multiphase flow, where the shock acceleration causes the second (embedded) phase to move with respect to the embedding medium. With sufficient seeding concentration, this leads to entrainment of the embedding phase that acquires a relative velocity dependent on the initial seeding, resulting in vortex formation in the flow.

  6. Criteria of classification applied to licensing of particle accelerators; Criterios de classificacao aplicados ao licenciamento de aceleradores de particulas

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Evaldo L.C., E-mail: evaldo@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Melo, Paulo F.F., E-mail: frutuoso@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    This work aims to bring to discussion the proposal of a new classification model toward to generating ionizing radiation, specifically particle accelerators, considering two parameters: the size of these facilities and the level of energy they operate, emphasizing large accelerators, which typically operate at higher levels of energy. Also motivated by the fact that the Brazilian rules do not provide an adequate standard of licensing for this size of installation, this work will seek to revise the existing classification, where generators of ionizing radiation (including particle accelerators) are considered up to the level of energy of 50 MeV.

  7. Milky Way's super-efficient particle accelerators caught in the act

    Science.gov (United States)

    2009-06-01

    Thanks to a unique "ballistic study" that combines data from ESO's Very Large Telescope and NASA's Chandra X-ray Observatory, astronomers have now solved a long-standing mystery of the Milky Way's particle accelerators. They show in a paper published today on Science Express that cosmic rays from our galaxy are very efficiently accelerated in the remnants of exploded stars. ESO PR Photo 23a/09 The rim of RCW 86 ESO PR Photo 23b/09 DSS + insert, annotated ESO PR Photo 23c/09 DSS image ESO PR Video 23a/09 Zoom-in RCW 86 During the Apollo flights astronauts reported seeing odd flashes of light, visible even with their eyes closed. We have since learnt that the cause was cosmic rays -- extremely energetic particles from outside the Solar System arriving at the Earth, and constantly bombarding its atmosphere. Once they reach Earth, they still have sufficient energy to cause glitches in electronic components. Galactic cosmic rays come from sources inside our home galaxy, the Milky Way, and consist mostly of protons moving at close to the speed of light, the "ultimate speed limit" in the Universe. These protons have been accelerated to energies exceeding by far the energies that even CERN's Large Hadron Collider will be able to achieve. "It has long been thought that the super-accelerators that produce these cosmic rays in the Milky Way are the expanding envelopes created by exploded stars, but our observations reveal the smoking gun that proves it", says Eveline Helder from the Astronomical Institute Utrecht of Utrecht University in the Netherlands, the first author of the new study. "You could even say that we have now confirmed the calibre of the gun used to accelerate cosmic rays to their tremendous energies", adds collaborator Jacco Vink, also from the Astronomical Institute Utrecht. For the first time Helder, Vink and colleagues have come up with a measurement that solves the long-standing astronomical quandary of whether or not stellar explosions produce enough

  8. Metazoan operons accelerate recovery from growth arrested states

    Science.gov (United States)

    Zaslaver, Alon; Baugh, L. Ryan; Sternberg, Paul W.

    2011-01-01

    Summary Existing theories explain why operons are advantageous in prokaryotes, but their occurrence in metazoans is an enigma. Nematode operon genes, typically consisting of growth genes, are significantly up-regulated during recovery from growth-arrested states. This expression pattern is anti-correlated to non-operon genes consistent with a competition for transcriptional resources. We find that transcriptional resources are initially limiting during recovery, and that recovering animals are highly sensitive to any additional decrease in transcriptional resources. Operons become advantageous because by clustering growth genes into operons, fewer promoters compete for the limited transcriptional machinery, effectively increasing the concentration of transcriptional resources, and accelerating recovery. Mathematical modeling reveals how a moderate increase in transcriptional resources can substantially enhance transcription rate and recovery. This design principle occurs in different nematodes and the chordate C. intestinalis. As transition from arrest to rapid growth is shared by many metazoans, operons could have evolved to facilitate these processes. PMID:21663799

  9. Metazoan operons accelerate recovery from growth-arrested states.

    Science.gov (United States)

    Zaslaver, Alon; Baugh, L Ryan; Sternberg, Paul W

    2011-06-10

    Existing theories explain why operons are advantageous in prokaryotes, but their occurrence in metazoans is an enigma. Nematode operon genes, typically consisting of growth genes, are significantly upregulated during recovery from growth-arrested states. This expression pattern is anticorrelated to nonoperon genes, consistent with a competition for transcriptional resources. We find that transcriptional resources are initially limiting during recovery and that recovering animals are highly sensitive to any additional decrease in transcriptional resources. We provide evidence that operons become advantageous because, by clustering growth genes into operons, fewer promoters compete for the limited transcriptional machinery, effectively increasing the concentration of transcriptional resources and accelerating recovery. Mathematical modeling reveals how a moderate increase in transcriptional resources can substantially enhance transcription rate and recovery. This design principle occurs in different nematodes and the chordate C. intestinalis. As transition from arrest to rapid growth is shared by many metazoans, operons could have evolved to facilitate these processes. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Slow waves in microchannel metal waveguides and application to particle acceleration

    Directory of Open Access Journals (Sweden)

    L. C. Steinhauer

    2003-06-01

    Full Text Available Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO_{2} lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ∼0.6  mm. The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  11. Particle acceleration efficiency and MHD characteristics of CIR-related shocks

    Science.gov (United States)

    Classen, H.-T.; Mann, G.; Keppler, E.

    1998-07-01

    During its southbound journey the Ulysses spacecraft crossed a series of corotating interaction regions (CIRs) building up due to the interaction of fast and slow solar wind streams. We analyse the forward and the reverse shocks marking off the 18 CIR encounters between July 1992 and December 1993. Our investigations look for a correlation between the particle acceleration efficiency expressed by the particle flux measured at the time of shock crossing and the MHD characteristics of the shocks; i.e., Alfven-Mach number (MA1), density and magnetic field compression ratios (r_N, r_B), and the angle between shock normal and upstream magnetic field (theta_ {Bn}). The results of this analysis show that the highest fluxes of 300 keV electrons and 1 MeV protons are observed when the conditions MA1 > 2.5 and 50(deg) <= theta_ {Bn} <= 75(deg) are simultaneously fulfilled by the shocks. These investigations are supplemented by a computation of the first critical Alfven-Mach number for typical parameters of CIR-related shocks. Furthermore, we discuss possible acceleration mechanisms by an analysis of the spectral indices of protons and Helium.

  12. Self-accelerating Dirac particles and prolonging the lifetime of relativistic fermions

    Science.gov (United States)

    Kaminer, Ido; Nemirovsky, Jonathan; Rechtsman, Mikael; Bekenstein, Rivka; Segev, Mordechai

    2015-03-01

    The Aharonov-Bohm effect predicts that two parts of the electron wavefunction can accumulate a phase difference even when they are confined to a region in space with zero electromagnetic field. Here we show that engineering the wavefunction of electrons, as accelerating shape-invariant solutions of the potential-free Dirac equation, fundamentally acts as a force and the electrons accumulate an Aharonov-Bohm-type phase--which is equivalent to a change in the proper time and is related to the twin-paradox gedanken experiment. This implies that fundamental relativistic effects such as length contraction and time dilation can be engineered by properly tailoring the initial conditions. As an example, we suggest the possibility of extending the lifetime of decaying particles, such as an unstable hydrogen isotope, or altering other decay processes. We find these shape-preserving Dirac wavefunctions to be part of a family of accelerating quantum particles, which includes massive/massless fermions/bosons of any spin.

  13. Slow waves in microchannel metal waveguides and application to particle acceleration

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2003-06-01

    Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO2 lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ˜0.6 mm). The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  14. Using Supra-Arcade Downflows as Probes of Particle Acceleration in Solar Flares

    Science.gov (United States)

    Savage, Sabrina

    2012-01-01

    Extracting information from coronal features above flares has become more reliable with the availability of increasingly higher spatial- and temporal-resolution data in recent decades. We are now able to sufficiently probe the region high above long-duration flaring active regions where reconnection is expected to be continually occurring. Flows in the supra-arcade region, first observed with Yohkoh/SXT, have been theorized to be associated with newly-reconnected outflowing loops. High resolution data appears to confirm these assertions. Assuming that these flows are indeed reconnection outflows, then the detection of those directed toward the solar surface (i.e. downflowing) should be associated with particle acceleration between the current sheet and the loop footpoints rooted in the chromosphere. RHESSI observations of highly energetic particles with respect to downflow detections could potentially constrain electron acceleration models. We provide measurements of these supra-arcade downflows (SADs) in relation to reconnection model parameters and present preliminary findings comparing the downflow timings with high-energy RHESSI lightcurves.

  15. First Observations of a Foreshock Bubble at Earth: Implications for Magnetospheric Activity and Energetic Particle Acceleration

    Science.gov (United States)

    Turner, D. L.; Omidi, N.; Sibeck, D. G.; Angelopoulos, V.

    2011-01-01

    Earth?s foreshock, which is the quasi-parallel region upstream of the bow shock, is a unique plasma region capable of generating several kinds of large-scale phenomena, each of which can impact the magnetosphere resulting in global effects. Interestingly, such phenomena have also been observed at planetary foreshocks throughout our solar system. Recently, a new type of foreshock phenomena has been predicted: foreshock bubbles, which are large-scale disruptions of both the foreshock and incident solar wind plasmas that can result in global magnetospheric disturbances. Here we present unprecedented, multi-point observations of foreshock bubbles at Earth using a combination of spacecraft and ground observations primarily from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, and we include detailed analysis of the events? global effects on the magnetosphere and the energetic ions and electrons accelerated by them, potentially by a combination of first and second order Fermi and shock drift acceleration processes. This new phenomena should play a role in energetic particle acceleration at collisionless, quasi-parallel shocks throughout the Universe.

  16. Report on the possible benefits of using high-temperature superconductor materials in particle-accelerator design. Final report, June-September 1987

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, L.; Collins, R.; Balko, B.

    1988-12-01

    This report discusses different design concepts for particle-beam accelerators. It demonstrates that with the use of high-temperature superconducting materials, a more-compact, lighter, and more-robust accelerator design can be realized for the space-based neutral particle beam (NPB) accelerator.

  17. Investigation of Propagation Characteristics of Twisted Hollow Waveguides for Particle Accelerator Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Joshua Lee [Univ. of Tennessee, Knoxville, TN (United States)

    2008-12-01

    A new class of accelerating structures employing a uniformly twisted waveguide is investigated. Twisted waveguides of various cross-sectional geometries are considered and analyzed. It is shown that such a twisted waveguide can support waves that travel at a speed slower than the speed of light c. The slow-wave properties of twisted structures are of interest because these slow-wave electromagnetic fields can be used in applications such as electron traveling wave tubes and linear particle accelerators. Since there is no exact closed form solution for the electromagnetic fields within a twisted waveguide or cavity, several previously proposed approximate methods are examined, and more effcient approaches are developed. It is found that the existing perturbation theory methods yield adequate results for slowly twisted structures; however, our efforts here are geared toward analyzing rapidly twisted structures using modifed finite difference methods specially suited for twisted structures. Although the method can handle general twisted structures, three particular cross sections are selected as representative cases for careful analysis. First, a slowly twisted rectangular cavity is analyzed as a reference case. This is because its shape is simple and perturbation theory already gives a good approximate solution for such slow twists rates. Secondly, a symmetrically notched circular cross section is investigated, since its longitudinal cross section is comparable to the well known disk-loaded cavity (used in many practical accelerator designs, including SLAC). Finally, a "dumbbell" shaped cross section is analyzed because of its similarity to the well-known TESLA-type accelerating cavity, which is of great importance because of its wide acceptance as a superconducting cavity. To validate the results of the developed theory and our extensive simulations, the newly developed numerical models are compared to commercial codes. Also, several prototypes are developed

  18. Mass-scaling as a method to constrain outflows and particle acceleration from low-luminosity accreting black holes

    Science.gov (United States)

    Connors, R. M. T.; Markoff, S.; Nowak, M. A.; Neilsen, J.; Ceccobello, C.; Crumley, P.; Froning, C. S.; Gallo, E.; Nip, J. E.

    2017-04-01

    The 'Fundamental Plane of black hole accretion' (FP), a relation between the radio luminosities (LR), X-ray luminosities (LX) and masses (MBH) of hard/quiescent state black hole binaries and low-luminosity active galactic nuclei, suggests some aspects of black hole accretion may be scale invariant. However, key questions still exist concerning the relationship between the inflow/outflow behaviour in the 'classic' hard state and quiescence, which may impact this scaling. We show that the broad-band spectra of A0620-00 and Sgr A* (the least luminous stellar mass/supermassive black holes on the FP) can be modelled simultaneously with a physically motivated outflow-dominated model where the jet power and all distances are scaled by the black hole mass. We find we can explain the data of both A0620-00 and Sgr A* (in its non-thermal flaring state) in the context of two outflow-model scenarios: (1) a synchrotron-self-Compton dominated state in which the jet plasma reaches highly sub-equipartition conditions (for the magnetic field with respect to that of the radiating particles), and (2) a synchrotron-dominated state in the fast-cooling regime in which particle acceleration occurs within the inner few gravitational radii of the black hole and plasma is close to equipartition. We show that it may be possible to further discriminate between models (1) and (2) through future monitoring of Sgr A*'s submm/infrared/X-ray emission, in particular via time lags between the variable emission in these bands.

  19. Scheme for proton-driven plasma-wakefield acceleration of positively charged particles in a hollow plasma channel

    Directory of Open Access Journals (Sweden)

    Longqing Yi (易龙卿

    2013-07-01

    Full Text Available A new scheme for accelerating positively charged particles in a plasma-wakefield accelerator is proposed. If the proton drive beam propagates in a hollow plasma channel, and the beam radius is of order of the channel width, the space charge force of the driver causes charge separation at the channel wall, which helps to focus the positively charged witness bunch propagating along the beam axis. In the channel, the acceleration buckets for positively charged particles are much larger than in the blowout regime of the uniform plasma, and stable acceleration over long distances is possible. In addition, phasing of the witness with respect to the wave can be tuned by changing the radius of the channel to ensure the acceleration is optimal. Two-dimensional simulations suggest that, for proton drivers likely available in future, positively charged particles can be stably accelerated over 1 km with the average acceleration gradient of 1.3  GeV/m.

  20. Characteristic, parametric, and diffracted transition X-ray radiation for observation of accelerated particle beam profile

    Science.gov (United States)

    Chaikovska, I.; Chehab, R.; Artru, X.; Shchagin, A. V.

    2017-07-01

    The applicability of X-ray radiation for the observation of accelerated particle beam profiles is studied. Three types of quasi-monochromatic X-ray radiation excited by the particles in crystals are considered: characteristic X-ray radiation, parametric X-ray radiation, diffracted transition X-ray radiation. Radiation is collected at the right angle to the particle beam direction. It is show that the most intensive differential yield of X-ray radiation from Si crystal can be provided by characteristic radiation at incident electron energies up to tens MeV, by parametric radiation at incident electron energies from tens to hundreds MeV, by diffracted transition X-ray radiation at GeV and multi-GeV electron energies. Therefore these kinds of radiation are proposed for application to beam profile observation in the corresponding energy ranges of incident electrons. Some elements of X-ray optics for observation of the beam profile are discussed. The application of the DTR as a source of powerful tunable monochromatic linearly polarized X-ray beam excited by a multi-GeV electron beam on the crystal surface is proposed.

  1. Charged-particle acceleration through laser irradiation of thin foils at Prague Asterix Laser System

    Science.gov (United States)

    Torrisi, Lorenzo; Cutroneo, Maria; Cavallaro, Salvatore; Musumeci, Paolo; Calcagno, Lucia; Wolowski, Jerzy; Rosinski, Marcin; Zaras-Szydlowska, Agnieszka; Ullschmied, Jiri; Krousky, Eduard; Pfeifer, Miroslav; Skala, Jiri; Velyhan, Andreiy

    2014-05-01

    Thin foils, 0.5-50 μm in thickness, have been irradiated in vacuum at Prague Asterix Laser System in Prague using 1015-16 W cm-2 laser intensity, 1315 nm wavelength, 300 ps pulse duration and different focal positions. Produced plasmas from metals and polymers films have been monitored in the forward and backward directions. Ion and electron accelerations have been investigated by using Thomson parabola spectrometer, x-ray streak camera, ion collectors and SiC semiconductor detectors, the latter employed in time-of-flight configuration. Ion acceleration up to about 3 MeV per charge state was measured in the forward direction. Ion and electron emissions were detected at different angles as a function of the irradiation conditions.

  2. Occupation Time of a Randomly Accelerated Particle on the Positive Half Axis: Results for the First Five Moments

    Science.gov (United States)

    Burkhardt, Theodore W.

    2017-11-01

    In the random acceleration process a point particle is accelerated by Gaussian white noise with zero mean. Although several fundamental statistical properties of the motion have been analyzed in detail, the statistics of occupation times is still not well understood. We consider the occupation or residence time T_+ on the positive x axis of a particle which is randomly accelerated on the unbounded x axis for a time t. The first two moments of T_+ were recently derived by Ouandji Boutcheng et al. (J Stat Mech 053213:1-10, 2016). With an alternate approach utilizing basis functions which have proved useful in other studies of randomly accelerated motion, results for the first five moments are obtained in this paper.

  3. Occupation Time of a Randomly Accelerated Particle on the Positive Half Axis: Results for the First Five Moments

    Science.gov (United States)

    Burkhardt, Theodore W.

    2017-10-01

    In the random acceleration process a point particle is accelerated by Gaussian white noise with zero mean. Although several fundamental statistical properties of the motion have been analyzed in detail, the statistics of occupation times is still not well understood. We consider the occupation or residence time T_+ on the positive x axis of a particle which is randomly accelerated on the unbounded x axis for a time t. The first two moments of T_+ were recently derived by Ouandji Boutcheng et al. (J Stat Mech 053213:1-10, 2016). With an alternate approach utilizing basis functions which have proved useful in other studies of randomly accelerated motion, results for the first five moments are obtained in this paper.

  4. Charged-particle acceleration in a reconnecting current sheet including multiple magnetic islands and a nonuniform background magnetic field

    Science.gov (United States)

    Li, Y.; Wu, N.; Lin, J.

    2017-09-01

    Context. Charged particles are accelerated to high energies in solar flares. Although we know that magnetic reconnection is an efficient mechanism in generating energetic particles, the detailed role it plays in accelerating particles is still unknown. Aims: We investigate particle acceleration by magnetic reconnection in the current sheet, including multiple islands and a guide field. Methods: The long current sheet produced by the disruption in the corona magnetic field is usually not stable to various plasma instabilities, among which the tearing mode is the most important, and magnetic islands start to form in the current sheet when these instabilities develop. Two reverse processes are typically observed in the sheet: cascading of large islands to smaller ones, and merging of small islands into larger ones. Coalescent reconnection consequently takes place between two adjacent islands when merging occurs. The electric field induced by the coalescent reconnection is opposite to the electric field of the primary large-scale reconnection. We studied particle acceleration in such a current sheet and examined in detail the dynamic properties of electrons and protons in the current sheet through test particle approach. Results: We found that some particles can be accelerated to high energies in a very short time, and some particles (near the coalescence reconnection site) are accelerated and decelerated back and forth by the primary and secondary electric fields. Particle motions show two distinct types along different trajectories: some particles are trapped around magnetic islands, and some escape from the current sheet mainly along open field lines. With the presence of a guide field, protons and electrons are found to eventually move in different directions. The energy spectra for both species follow a double power-law shape. The softer components of the power-law spectrum are due to the particles that are trapped and circulate around magnetic islands, while the

  5. SimTrack: A compact c++ library for particle orbit and spin tracking in accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yun [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    SimTrack is a compact c++ library of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam-beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam-beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam-beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this article, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.

  6. Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

    Science.gov (United States)

    Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-11-28

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet. Copyright © 2014, American Association for the Advancement of Science.

  7. GPU-accelerated Red Blood Cells Simulations with Transport Dissipative Particle Dynamics

    CERN Document Server

    Blumers, Ansel L; Li, Zhen; Li, Xuejin; Karniadakis, George E

    2016-01-01

    Mesoscopic numerical simulations provide a unique approach for the quantification of the chemical influences on red blood cell functionalities. The transport Dissipative Particles Dynamics (tDPD) method can lead to such effective multiscale simulations due to its ability to simultaneously capture mesoscopic advection, diffusion, and reaction. In this paper, we present a GPU-accelerated red blood cell simulation package based on a tDPD adaptation of our red blood cell model, which can correctly recover the cell membrane viscosity, elasticity, bending stiffness, and cross-membrane chemical transport. The package essentially processes all computational workloads in parallel by GPU, and it incorporates multi-stream scheduling and non-blocking MPI communications to improve inter-node scalability. Our code is validated for accuracy and compared against the CPU counterpart for speed. Strong scaling and weak scaling are also presented to characterizes scalability. We observe a speedup of 10.1 on one GPU over all 16 c...

  8. Application of Atmospheric Plasma-Sprayed Ferrite Layers for Particle Accelerators

    CERN Document Server

    Caspers, F; Federmann, S; Taborelli, M; Schulz, C; Bobzin, K; Wu, J

    2013-01-01

    A common problem in all kinds of cavity-like structures in particle accelerators is the occurrence of RF-resonances. Typically, ferrite plates attached to the walls of such structures as diagnostic devices, kickers or collimators, are used to dampen those undesired modes. However, the heat transfer rate from these plates to the walls is rather limited. Brazing ferrite plates to the walls is not possible in most cases due to the different thermal expansion coefficients. To overcome those limitations, atmospheric plasma spraying techniques have been investigated. Ferrite layers with a thickness from 50 μm to about 300 μm can be deposited on metallic surfaces like stainless steel exhibiting good thermal contact and still reasonable absorption properties. In this paper the technological aspects of plasma deposition are discussed and results of specifically developed RF loss measurement procedures for such thin magnetically lossy layers on metal are presented.

  9. Experimental Observation of Direct Particle Acceleration by Stimulated Emission of Radiation

    Science.gov (United States)

    Banna, Samer; Berezovsky, Valery; Schächter, Levi

    2006-09-01

    We report the first experimental evidence for direct particle acceleration by stimulated emission of radiation. In the framework of this proof-of-principle experiment, a 45 MeV electron macrobunch was modulated by a high-power CO2 laser and then injected into an excited CO2 gas mixture. The emerging microbunches experienced a 0.15% relative change in the kinetic energy, in a less than 40 cm long interaction region. According to our experimental results, a fraction of these electrons have gained more than 200 keV each, implying that such an electron has undergone an order of magnitude of 2×106 collisions of the second kind.

  10. Proposed parameters for a circular particle accelerator for proton beam therapy obtained by genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Gustavo L.; Campos, Tarcísio P.R., E-mail: gustavo.lobato@ifmg.edu.br, E-mail: tprcampos@pq.cnpq.br, E-mail: gustavo.lobato@ifmg.edu.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    This paper brings to light optimized proposal for a circular particle accelerator for proton beam therapy purposes (named as ACPT). The methodology applied is based on computational metaheuristics based on genetic algorithms (GA) were used to obtain optimized parameters of the equipment. Some fundamental concepts in the metaheuristics developed in Matlab® software will be presented. Four parameters were considered for the proposed modeling for the equipment, being: potential difference, magnetic field, length and radius of the resonant cavity. As result, this article showed optimized parameters for two ACPT, one of them used for ocular radiation therapy, as well some parameters that will allow teletherapy, called in order ACPT - 65 and ACPT - 250, obtained through metaheuristics based in GA. (author)

  11. Shock creation and particle acceleration driven by plasma expansion into a rarefied medium

    CERN Document Server

    Sarri, G; Dieckmann, M E; Borghesi, M

    2010-01-01

    The expansion of a dense plasma through a more rarefied ionised medium is a phenomenon of interest in various physics environments ranging from astrophysics to high energy density laser- matter laboratory experiments. Here this situation is modeled via a 1D Particle-In-Cell simulation; a jump in the plasma density of a factor of 100 is introduced in the middle of an otherwise equally dense electron-proton plasma with an uniform proton and electron temperature of 10eV and 1keV respectively. The diffusion of the dense plasma, through the rarified one, triggers the onset of different nonlinear phenomena such as a strong ion-acoustic shock wave and a rarefaction wave. Secondary structures are detected, some of which are driven by a drift instability of the rarefaction wave. Efficient proton acceleration occurs ahead of the shock, bringing the maximum proton velocity up to 60 times the initial ion thermal speed.

  12. Experimental and Numerical Studies of Particle Acceleration by an Active Microwave Medium

    CERN Document Server

    Schoessow, Paul

    2005-01-01

    There has been considerable theoretical work on the so-called PASER concept, in which a particle beam is accelerated directly by absorbing energy from an active medium, analogous to the amplification of an optical signal in a laser. Use of an active microwave (maser) medium would have the advantage of requiring relaxed beam quality (mm vs. nm characteristic beam dimensions). Recent work using electron paramagnetic resonance (EPR) techniques has demonstrated activity in the microwave regime (i.e. negative imaginary part of the magnetic susceptibility) for a class of organic compounds. A solution of fullerene (C60) in a liquid crystal solvent has been reported in the literature to possess a maser transition in the X-band region. An external DC magnetic field is required to obtain the effect; the frequency of the maser transition is adjustable by varying the magnetic field strength. We will report on the development of numerical and laboratory tools to evaluate the use of this material for accelerator applicatio...

  13. Radio Evolution of Supernova Remnants Including Nonlinear Particle Acceleration: Insights from Hydrodynamic Simulations

    Science.gov (United States)

    Pavlović, Marko Z.; Urošević, Dejan; Arbutina, Bojan; Orlando, Salvatore; Maxted, Nigel; Filipović, Miroslav D.

    2018-01-01

    We present a model for the radio evolution of supernova remnants (SNRs) obtained by using three-dimensional hydrodynamic simulations coupled with nonlinear kinetic theory of cosmic-ray (CR) acceleration in SNRs. We model the radio evolution of SNRs on a global level by performing simulations for a wide range of the relevant physical parameters, such as the ambient density, supernova (SN) explosion energy, acceleration efficiency, and magnetic field amplification (MFA) efficiency. We attribute the observed spread of radio surface brightnesses for corresponding SNR diameters to the spread of these parameters. In addition to our simulations of Type Ia SNRs, we also considered SNR radio evolution in denser, nonuniform circumstellar environments modified by the progenitor star wind. These simulations start with the mass of the ejecta substantially higher than in the case of a Type Ia SN and presumably lower shock speed. The magnetic field is understandably seen as very important for the radio evolution of SNRs. In terms of MFA, we include both resonant and nonresonant modes in our large-scale simulations by implementing models obtained from first-principles, particle-in-cell simulations and nonlinear magnetohydrodynamical simulations. We test the quality and reliability of our models on a sample consisting of Galactic and extragalactic SNRs. Our simulations give Σ ‑ D slopes between ‑4 and ‑6 for the full Sedov regime. Recent empirical slopes obtained for the Galactic samples are around ‑5, while those for the extragalactic samples are around ‑4.

  14. Modeling and Visualizing the Particle Beam in the Rare Isotope Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, Christopher [Argonne National Lab., IL (United States); Erdelyi, Bela [Argonne National Lab., IL (United States); Northern Illinois Univ. (United States)

    2006-01-01

    Argonne National Laboratory is actively pursuing research and design for a Rare Isotope Accelerator (RIA) facility that will aid basic research in nuclear physics by creating beams of unstable isotopes. Such a facility has been labeled as a high priority by the joint Department of Energy and National Science Foundation Nuclear Science Advisory Committee because it will allow more study on the nature of nucleonic matter, the origin of the elements, the Standard Model, and nuclear medicine. An important part of this research is computer simulations that model the behavior of the particle beam, specifically in the Fragment Separator. The Fragment Separator selects isotopes based on their trajectory in electromagnetic fields and then uses absorbers to separate particles with a certain mass and charge from the rest of the beam. This project focused on the development of a multivariate, correlated Gaussian distribution to model the distribution of particles in the beam as well as visualizations and analysis to view how this distribution changed when passing through an absorber. The distribution was developed in the COSY INFINITY programming language. The user inputs a covariance matrix and a vector of means for the six phase space variables, and the program outputs a vector of correlated, Gaussian random variables. A variety of random test cases were conducted in two, three and six variables. In each case, the expectation values, variances and covariances were calculated and they converged to the input values. The output of the absorber code is a large data set that stores all of the variables for each particle in the distribution. It is impossible to analyze such a large data set by hand, so visualizations and summary statistics had to be developed. The first visualization is a three-dimensional graph that shows the number of each isotope present after each slice of the absorber. A second graph plots any of the six phase space variables against any of the others to see

  15. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    CERN Document Server

    Assmann, R; Bohl, T; Bracco, C; Buttenschön, B; Butterworth, A; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Feldbaumer, E; Fonseca, R A; Goddard, B; Gross, M; Grulke, O; Gschwendtner, E; Holloway, J; Huang, C; Jaroszynski, D; Jolly, S; Kempkes, P; Lopes, N; Lotov, K; Machacek, J; Mandry, S R; McKenzie, J W; Meddahi, M; Militsyn, B L; Moschuering, N; Muggli, P; Najmudin, Z; Noakes, T C Q; Norreys, P A; Öz, E; Pardons, A; Petrenko, A; Pukhov, A; Rieger, K; Reimann, O; Ruhl, H; Shaposhnikova, E; Silva, L O; Sosedkin, A; Tarkeshian, R; Trines, R M G N; Tückmantel, T; Vieira, J; Vincke, H; Wing, M; Xia G , G

    2014-01-01

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN { the AWAKE experiment { has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

  16. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    CERN Document Server

    Assmann, R; Bohl, T; Bracco, C; Buttenschon, B; Butterworth, A; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Feldbaumer, E; Fonseca, R A; Goddard, B; Gross, M; Grulke, O; Gschwendtner, E; Holloway, J; Huang, C; Jaroszynski, D; Jolly, S; Kempkes, P; Lopes, N; Lotov, K; Machacek, J; Mandry, S R; McKenzie, J W; Meddahi, M; Militsyn, B L; Moschuering, N; Muggli, P; Najmudin, Z; Noakes, T C Q; Norreys, P A; Oz, E; Pardons, A; Petrenko, A; Pukhov, A; Rieger, K; Reimann, O; Ruhl, H; Shaposhnikova, E; Silva, L O; Sosedkin, A; Tarkeshian, R; Trines, R M G N; Tuckmantel, T; Vieira, J; Vincke, H; Wing, M; Xia, G

    2014-01-01

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN -- the AWAKE experiment -- has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

  17. The role of particle ripening on the creep acceleration of Nimonic 263 superalloy

    Directory of Open Access Journals (Sweden)

    Angella Giuliano

    2014-01-01

    Full Text Available Physically based constitutive equations need to incorporate the most relevant microstructural features of materials to adequately describe their mechanical behaviour. To accurately model the creep behaviour of precipitation hardened alloys, the value and the evolution of strengthening particle size are important parameters to be taken into account. In the present work, creep tests have been run on virgin and overaged (up to 3500 h at 800 ∘C Nimonic 263, a polycrystalline nickel base superalloy used for combustion chambers of gas turbines. The experimental results suggest that the reinforcing particle evolution is not the main reason for the creep acceleration that seems to be better described by a strain correlated damage, such as the accumulation of mobile dislocations or the grain boundary cavitation. The coarsened microstructure, obtained by overageing the alloy at high temperature before creep testing, mainly influences the initial stage of the creep, resulting in a higher minimum creep rate and a corresponding reduction of the creep resistance.

  18. Simulation and experimental studies on electron cloud effects in particle accelerators

    CERN Document Server

    Romano, Annalisa; Cimino, Roberto; Iadarola, Giovanni; Rumolo, Giovanni

    Electron Cloud (EC) effects represent a serious limitation for particle accelerators operating with intense beams of positively charged particles. This Master thesis work presents simulation and experimental studies on EC effects carried out in collaboration with the European Organization for Nuclear Research (CERN) in Geneva and with the INFN-LNF laboratories in Frascati. During the Long Shut- down 1 (LS1, 2013-2014), a new detector for EC measurements has been installed in one of the main magnets of the CERN Proton Synchrotron (PS) to study the EC formation in presence of a strong magnetic field. The aim is to develop a reli- able EC model of the PS vacuum chamber in order to identify possible limitation for the future high intensity and high brightness beams foreseen by Large Hadron Collider (LHC) Injectors Upgrade (LIU) project. Numerical simulations with the new PyECLOUD code were performed in order to quantify the expected signal at the detector under different beam conditions. The experimental activity...

  19. GPU accelerated simulations of 3D deterministic particle transport using discrete ordinates method

    Science.gov (United States)

    Gong, Chunye; Liu, Jie; Chi, Lihua; Huang, Haowei; Fang, Jingyue; Gong, Zhenghu

    2011-07-01

    Graphics Processing Unit (GPU), originally developed for real-time, high-definition 3D graphics in computer games, now provides great faculty in solving scientific applications. The basis of particle transport simulation is the time-dependent, multi-group, inhomogeneous Boltzmann transport equation. The numerical solution to the Boltzmann equation involves the discrete ordinates ( Sn) method and the procedure of source iteration. In this paper, we present a GPU accelerated simulation of one energy group time-independent deterministic discrete ordinates particle transport in 3D Cartesian geometry (Sweep3D). The performance of the GPU simulations are reported with the simulations of vacuum boundary condition. The discussion of the relative advantages and disadvantages of the GPU implementation, the simulation on multi GPUs, the programming effort and code portability are also reported. The results show that the overall performance speedup of one NVIDIA Tesla M2050 GPU ranges from 2.56 compared with one Intel Xeon X5670 chip to 8.14 compared with one Intel Core Q6600 chip for no flux fixup. The simulation with flux fixup on one M2050 is 1.23 times faster than on one X5670.

  20. Advanced 3D Poisson solvers and particle-in-cell methods for accelerator modeling

    Energy Technology Data Exchange (ETDEWEB)

    Serafini, David B; McCorquodale, Peter; Colella, Phillip [Lawrence Berkeley National Lab, Applied Numerical Algorithms Group, SciDAC Applied Differential Equations Center (United States)

    2005-01-01

    We seek to improve on the conventional FFT-based algorithms for solving the Poisson equation with infinite-domain (open) boundary conditions for large problems in accelerator modeling and related areas. In particular, improvements in both accuracy and performance are possible by combining several technologies: the method of local corrections (MLC); the James algorithm; and adaptive mesh refinement (AMR). The MLC enables the parallelization (by domain decomposition) of problems with large domains and many grid points. This improves on the FFT-based Poisson solvers typically used as it doesn't require the all-to-all communication pattern that parallel 3d FFT algorithms require, which tends to be a performance bottleneck on current (and foreseeable) parallel computers. In initial tests, good scalability up to 1000 processors has been demonstrated for our new MLC solver. An essential component of our approach is a new version of the James algorithm for infinite-domain boundary conditions for the case of three dimensions. By using a simplified version of the fast multipole method in the boundary-to-boundary potential calculation, we improve on the performance of the Hockney algorithm typically used by reducing the number of grid points by a factor of 8, and the CPU costs by a factor of 3. This is particularly important for large problems where computer memory limits are a consideration. The MLC allows for the use of adaptive mesh refinement, which reduces the number of grid points and increases the accuracy in the Poisson solution. This improves on the uniform grid methods typically used in PIC codes, particularly in beam problems where the halo is large. Also, the number of particles per cell can be controlled more closely with adaptivity than with a uniform grid. To use AMR with particles is more complicated than using uniform grids. It affects depositing particles on the non-uniform grid, reassigning particles when the adaptive grid changes and maintaining the

  1. Simulations of Particle Acceleration beyond the Classical Synchrotron Burnoff Limit in Magnetic Reconnection: An Explanation of the Crab Flares

    Science.gov (United States)

    Cerutti, B.; Werner, G. R.; Uzdensky, D. A.; Begelman, M. C.

    2013-06-01

    It is generally accepted that astrophysical sources cannot emit synchrotron radiation above 160 MeV in their rest frame. This limit is given by the balance between the accelerating electric force and the radiation reaction force acting on the electrons. The discovery of synchrotron gamma-ray flares in the Crab Nebula, well above this limit, challenges this classical picture of particle acceleration. To overcome this limit, particles must accelerate in a region of high electric field and low magnetic field. This is possible only with a non-ideal magnetohydrodynamic process, like magnetic reconnection. We present the first numerical evidence of particle acceleration beyond the synchrotron burnoff limit, using a set of two-dimensional particle-in-cell simulations of ultra-relativistic pair plasma reconnection. We use a new code, Zeltron, that includes self-consistently the radiation reaction force in the equation of motion of the particles. We demonstrate that the most energetic particles move back and forth across the reconnection layer, following relativistic Speiser orbits. These particles then radiate >160 MeV synchrotron radiation rapidly, within a fraction of a full gyration, after they exit the layer. Our analysis shows that the high-energy synchrotron flux is highly variable in time because of the strong anisotropy and inhomogeneity of the energetic particles. We discover a robust positive correlation between the flux and the cut-off energy of the emitted radiation, mimicking the effect of relativistic Doppler amplification. A strong guide field quenches the emission of >160 MeV synchrotron radiation. Our results are consistent with the observed properties of the Crab flares, supporting the reconnection scenario.

  2. Particle acceleration by inductive electric fields in the Earth’s magnetosphere

    Science.gov (United States)

    Ilie, Raluca; Daldorff, Lars K. S.; Ganushkina, Natalia; Liemohn, Michael

    2015-04-01

    The terrestrial magnetosphere has the capability to rapidly accelerate charged particles up to very high energies over relatively short times and distances, leading to an increase in the near Earth currents. These energetic particles are injected from the magnetotail into the inner magnetosphere through two primary mechanisms. One transport method is the potential-driven convection. This occurs during periods of southward Interplanetary Magnetic Field (IMF), which allows part of the dawn-to-dusk solar wind electric field to effectively map down to the polar ionosphere. The second transport process, substorm activity, involves a sudden reconfiguration of the magnetic field and the creation of transient induced electric fields. The relative contribution of potential and inductive electric field driven convection resulting in the development of the storm-time ring current has remained an unresolved question in Geospace research.Since the energy of charged particles can be altered only by means of electric fields, knowledge of the relative contribution of potential versus inductive electric fields at intensifying the hot ion population in the inner magnetosphere is required. However, it is not possible to distinguish the two terms by only measuring the electric field. Therefore assessing the importance of induced electric field is possible by thorough examination of the time varying magnetic field and current systems using global modeling of the entire system.The induced electric field is calculated as a 3D integration over the entire magnetosphere domain. However, though computationally challenging, the full volume integration approach removes the need to trace independent field lines and lifts the assumption that the magnetic field lines can be treated as frozen in a stationary ionosphere.In this work, we quantitatively assess the relative contributions on potential and inductive electric fields at driving plasma sheet ions into the inner magnetosphere, as well as

  3. Steady Particle States of Revised Electromagnetics

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2006-07-01

    Full Text Available A revised Lorentz invariant electromagnetic theory leading beyond Maxwell’s equations, and to a form of extended quantum electrodynamics, has been elaborated on the basis of a nonzero electric charge density and a nonzero electric field divergence in the vacuum state. Among the applications of this theory, there are steady electromagnetic states having no counterpart in conventional theory and resulting in models of electrically charged and neutral leptons, such as the electron and the neutrino. The analysis of the electron model debouches into a point-charge-like geometry with a very small characteristic radius but having finite self-energy. This provides an alternative to the conventional renormalization procedure. In contrast to conventional theory, an integrated radial force balance can further be established in which the electron is prevented from “exploding” under the action of its net self-charge. Through a combination of variational analysis and an investigation of the radial force balance, a value of the electronic charge has been deduced which deviates by only one percent from that obtained in experiments. This deviation requires further investigation. A model of the neutrino finally reproduces some of the basic features, such as a small but nonzero rest mass, an angular momentum but no magnetic moment, and long mean free paths in solid matter.

  4. Steady Particle States of Revised Electromagnetics

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2006-07-01

    Full Text Available A revised Lorentz invariant electromagnetic theory leading beyond Maxwell's equations, and to a form of extended quantum electrodynamics, has been elaborated on the basis of a nonzero electric charge density and a nonzero electric field divergence in the vacuum state. Among the applications of this theory, there are steady electromagnetic states having no counterpart in conventional theory and resulting in models of electrically charged and neutral leptons, such as the electron and the neutrino. The analysis of the electron model debouches into a point-charge-like geometry with a very small characteristic radius but having finite self-energy. This provides an alternative to the conventional renormalization procedure. In contrast to conventional theory, an integrated radial force balance can further be established in which the electron is prevented from "exploding" under the action of its net self-charge. Through a combination of variational analysis and an investigation of the radial force balance, a value of the electronic charge has been deduced which deviates by only one percent from that obtained in experiments. This deviation requires further investigation. A model of the neutrino finally reproduces some of the basic features, such as a small but nonzero rest mass, an angular momentum but no magnetic moment, and long mean free paths in solid matter.

  5. Matrix product states for interacting particles without hardcore constraints

    Science.gov (United States)

    Chatterjee, Amit Kumar; Mohanty, P. K.

    2017-12-01

    We construct matrix product steady states for a class of interacting particle systems where particles do not obey hardcore exclusion, meaning each site can occupy any number of particles subjected to the global conservation of the total number of particles in the system. To represent the arbitrary occupancy of the sites, the matrix product ansatz here requires an infinite set of matrices which in turn leads to an algebra involving an infinite number of matrix equations. We show that these matrix equations, in fact, can be reduced to a single functional relation when the matrices are parametric functions of the representative occupation number. We demonstrate this matrix formulation in a class of stochastic particle hopping processes on a one dimensional periodic lattice where hop rates depend on the occupation numbers of the departure site and its neighbors within a finite range; this includes some well known stochastic processes like, the totally or partially asymmetric zero range process, misanthrope process and finite range process.

  6. SIMULATION OF ENERGETIC PARTICLE TRANSPORT AND ACCELERATION AT SHOCK WAVES IN A FOCUSED TRANSPORT MODEL: IMPLICATIONS FOR MIXED SOLAR PARTICLE EVENTS

    Energy Technology Data Exchange (ETDEWEB)

    Kartavykh, Y. Y.; Dröge, W. [Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg (Germany); Gedalin, M. [Department of Physics, Ben-Gurion Unversity of the Negev, Beer-Sheva (Israel)

    2016-03-20

    We use numerical solutions of the focused transport equation obtained by an implicit stochastic differential equation scheme to study the evolution of the pitch-angle dependent distribution function of protons in the vicinity of shock waves. For a planar stationary parallel shock, the effects of anisotropic distribution functions, pitch-angle dependent spatial diffusion, and first-order Fermi acceleration at the shock are examined, including the timescales on which the energy spectrum approaches the predictions of diffusive shock acceleration theory. We then consider the case that a flare-accelerated population of ions is released close to the Sun simultaneously with a traveling interplanetary shock for which we assume a simplified geometry. We investigate the consequences of adiabatic focusing in the diverging magnetic field on the particle transport at the shock, and of the competing effects of acceleration at the shock and adiabatic energy losses in the expanding solar wind. We analyze the resulting intensities, anisotropies, and energy spectra as a function of time and find that our simulations can naturally reproduce the morphologies of so-called mixed particle events in which sometimes the prompt and sometimes the shock component is more prominent, by assuming parameter values which are typically observed for scattering mean free paths of ions in the inner heliosphere and energy spectra of the flare particles which are injected simultaneously with the release of the shock.

  7. A note on the acceleration phase of high-energy particles in the solar flare on 7 July, 1966.

    Science.gov (United States)

    Sakurai, K.

    1971-01-01

    The acceleration phase of solar cosmic rays and relativistic electrons is studied on the basis of the observational data available on the optical, radio, X-ray, and particle events associated with the solar flare that occurred on July 7, 1966. The generating process of hydromagnetic shock waves which excited the type-II radio burst detected at a frequency below about 100 MHz is also discussed. The results of the study suggest that no secondary acceleration process after the explosive phase can contribute much to the generation of high energy particles. The ejection of solar cosmic rays and relativistic electrons seems to be related to the expansion of the magnetic bulge which can trap accelerated electrons from the triggering region of solar flares.

  8. Effect of particle size on iron nanoparticle oxidation state

    Energy Technology Data Exchange (ETDEWEB)

    Lombardo, Jeffrey J.; Lysaght, Andrew C. [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, 97 North Eagleville Road, Storrs, CT 06269-3139 (United States); Goberman, Daniel G. [Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136 (United States); Chiu, Wilson K.S., E-mail: wchiu@engr.uconn.edu [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, 97 North Eagleville Road, Storrs, CT 06269-3139 (United States)

    2012-01-01

    Selecting catalyst particles is a very important part of carbon nanotube growth, although the properties of these nanoscale particles are unclear. In this article iron nanoparticles are analyzed through the use of atomic force microscopy and x-ray photoelectron spectroscopy in order to understand how the size affects the chemical composition of nanoparticles and thus their physical structure. Initially, atomic force microscopy was used to confirm the presence of iron particles, and to determine the average size of the particles. Next an analytical model was developed to estimate particle size as a function of deposition time using inputs from atomic force microscopy measurement. X-ray photoelectron spectroscopy analysis was then performed with a focus on the spectra relating to the 2p Fe electrons to study the chemical state of the particles as a function of time. It was shown that as the size of nanoparticles decreased, the oxidation state of the particles changed due to a high proportion of atoms on the surface.

  9. Effect of low temperature baking on the RF properties of niobium superconducting cavities for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Gianluigi Ciovati

    2004-03-01

    Radio-frequency superconducting (SRF) cavities are widely used to accelerate a charged particle beam in particle accelerators. The performance of SRF cavities made of bulk niobium has significantly improved over the last ten years and is approaching the theoretical limit for niobium. Nevertheless, RF tests of niobium cavities are still showing some ''anomalous'' losses that require a better understanding in order to reliably obtain better performance. These losses are characterized by a marked dependence of the surface resistance on the surface electromagnetic field and can be detected by measuring the quality factor of the resonator as a function of the peak surface field. A low temperature (100 C-150 C) ''in situ'' bake under ultra-high vacuum has been successfully applied as final preparation of niobium RF cavities by several laboratories over the last few years. The benefits reported consist mainly of an improvement of the cavity quality factor at low field and a recovery from ''anomalous'' losses (so-called ''Q-drop'') without field emission at higher field. A series of experiments with a CEBAF single-cell cavity have been carried out at Jefferson Lab to carefully investigate the effect of baking at progressively higher temperatures for a fixed time on all the relevant material parameters. Measurements of the cavity quality factor in the temperature range 1.37 K-280 K and resonant frequency shift between 6 K-9.3 K provide information about the surface resistance, energy gap, penetration depth and mean free path. The experimental data have been analyzed with the complete BCS theory of superconductivity. The hydrogen content of small niobium samples inserted in the cavity during its surface preparation was analyzed with Nuclear Reaction Analysis (NRA). The single-cell cavity has been tested at three different temperatures before and after baking to gain some insight on thermal

  10. Global distribution of secondary organic aerosol particle phase state

    Science.gov (United States)

    Shiraiwa, M.; Li, Y., Sr.; Tsimpidi, A.; Karydis, V.; Berkemeier, T.; Pandis, S. N.; Lelieveld, J.; Koop, T.; Poeschl, U.

    2016-12-01

    Secondary organic aerosols (SOA) account for a large fraction of submicron particles in the atmosphere and play a key role in aerosol effects on climate, air quality and public health. The formation and aging of SOA proceed through multiple steps of chemical reaction and mass transport in the gas and particle phases, which is challenging for the interpretation of field measurements and laboratory experiments as well as accurate representation of SOA evolution in atmospheric aerosol models. SOA particles can adopt liquid, semi-solid and amorphous solid (glassy) phase states depending on chemical composition, relative humidity and temperature. The particle phase state is crucial for various atmospheric gas-particle interactions, including SOA formation, heterogeneous and multiphase reactions and ice nucleation. We found that organic compounds with a wide variety of functional groups fall into molecular corridors, characterized by a tight inverse correlation between molar mass and volatility. Based on the concept of molecular corridors, we develop a method to estimate glass transition temperatures based on the molar mass and molecular O:C ratio of SOA components, which is a key property for determination of particle phase state. We use the global chemistry climate model EMAC with the organic aerosol module ORACLE to predict the atmospheric SOA phase state. For the planetary boundary layer, global simulations indicate that SOA is mostly liquid in tropical and polar air with high relative humidity, semi-solid in the mid-latitudes, and solid over dry lands. We find that in the middle and upper troposphere (>500 hPa) SOA should be mostly in a glassy solid phase state. Thus, slow diffusion of water, oxidants, and organic molecules could kinetically limit gas-particle interactions of SOA in the free and upper troposphere, promote ice nucleation and facilitate long-range transport of reactive and toxic organic pollutants embedded within SOA.

  11. Classical many-particle systems with unique disordered ground states.

    Science.gov (United States)

    Zhang, G; Stillinger, F H; Torquato, S

    2017-10-01

    Classical ground states (global energy-minimizing configurations) of many-particle systems are typically unique crystalline structures, implying zero enumeration entropy of distinct patterns (aside from trivial symmetry operations). By contrast, the few previously known disordered classical ground states of many-particle systems are all high-entropy (highly degenerate) states. Here we show computationally that our recently proposed "perfect-glass" many-particle model [Sci. Rep. 6, 36963 (2016)10.1038/srep36963] possesses disordered classical ground states with a zero entropy: a highly counterintuitive situation . For all of the system sizes, parameters, and space dimensions that we have numerically investigated, the disordered ground states are unique such that they can always be superposed onto each other or their mirror image. At low energies, the density of states obtained from simulations matches those calculated from the harmonic approximation near a single ground state, further confirming ground-state uniqueness. Our discovery provides singular examples in which entropy and disorder are at odds with one another. The zero-entropy ground states provide a unique perspective on the celebrated Kauzmann-entropy crisis in which the extrapolated entropy of a supercooled liquid drops below that of the crystal. We expect that our disordered unique patterns to be of value in fields beyond glass physics, including applications in cryptography as pseudorandom functions with tunable computational complexity.

  12. Evidence for particle re-acceleration in the radio relic in the galaxy cluster PLCKG287.0+32.9

    Energy Technology Data Exchange (ETDEWEB)

    Bonafede, A.; Brüggen, M. [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Intema, H. T. [National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States); Girardi, M. [Dipartimento di Fisica-Sezione di Astronomia, Universitá di Trieste, via Tiepolo 11, I-34143 Trieste (Italy); Nonino, M. [INAF—Osservatorio Astronomico di Trieste, via Tiepolo 11, I-34143 Trieste (Italy); Kantharia, N. [National center for Radio Astrophysics, TIFR, Post Bag 3, Ganeshkhind, Pune 411 007 (India); Van Weeren, R. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Röttgering, H. J. A. [Leiden Observatory, Leiden University, 2300 RA Leiden (Netherlands)

    2014-04-10

    Radio relics are diffuse radio sources observed in galaxy clusters, probably produced by shock acceleration during cluster-cluster mergers. Their large size, of the order of 1 Mpc, indicates that the emitting electrons need to be (re)accelerated locally. The usually invoked diffusive shock acceleration models have been challenged by recent observations and theory. We report the discovery of complex radio emission in the Galaxy cluster PLCKG287.0+32.9, which hosts two relics, a radio halo, and several radio filamentary emission. Optical observations suggest that the cluster is elongated, likely along an intergalactic filament, and displays a significant amount of substructure. The peculiar features of this radio relic are that (1) it appears to be connected to the lobes of a radio galaxy and (2) the radio spectrum steepens on either side of the radio relic. We discuss the origins of these features in the context of particle re-acceleration.

  13. SHOCK-CLOUD INTERACTION AND PARTICLE ACCELERATION IN THE SOUTHWESTERN LIMB OF SN 1006

    Energy Technology Data Exchange (ETDEWEB)

    Miceli, M.; Orlando, S.; Bocchino, F. [INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy); Acero, F. [ORAU/NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States); Dubner, G. [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Decourchelle, A., E-mail: miceli@astropa.unipa.it [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, F-91191 Gif-sur-Yvette (France)

    2014-02-20

    The supernova remnant SN 1006 is a powerful source of high-energy particles and evolves in a relatively tenuous and uniform environment despite interacting with an atomic cloud in its northwestern limb. The X-ray image of SN 1006 reveals an indentation in the southwestern part of the shock front and the H I maps show an isolated (southwestern) cloud, having the same velocity as the northwestern cloud, whose morphology fits perfectly in the indentation. We performed spatially resolved spectral analysis of a set of small regions in the southwestern nonthermal limb and studied the deep X-ray spectra obtained within the XMM-Newton SN 1006 Large Program. We also analyzed archive H I data, obtained by combining single-dish and interferometric observations. We found that the best-fit value of N {sub H} derived from the X-ray spectra significantly increases in regions corresponding to the southwestern cloud, while the cutoff energy of the synchrotron emission decreases. The N {sub H} variation corresponds perfectly with the H I column density of the southwestern cloud, as measured from the radio data. The decrease in the cutoff energy at the indentation clearly reveals that the back side of the cloud is actually interacting with the remnant. The southwestern limb therefore presents a unique combination of efficient particle acceleration and high ambient density, thus being the most promising region for γ-ray hadronic emission in SN 1006. We estimate that such emission will be detectable with the Fermi telescope within a few years.

  14. Shock-drift particle acceleration in superluminal shocks - A model for hot spots in extragalactic radio sources

    Science.gov (United States)

    Begelman, Mitchell C.; Kirk, John G.

    1990-01-01

    Shock-drift acceleration at relativistic shock fronts is investigated using a fully relativistic treatment of both the microphysics of the shock-drift acceleration and the macrophysics of the shock front. By explicitly tracing particle trajectories across shocks, it is shown how the adiabatic invariance of a particle's magnetic moment breaks down as the upstream shock speed becomes relativistic, and is recovered at subrelativistic velocities. These calculations enable the mean increase in energy of a particle which encounters the shock with a given pitch angle to be calculated. The results are used to construct the downstream electron distribution function in terms of the incident distribution function and the bulk properties of the shock. The synchrotron emissivity of the transmitted distribution is calculated, and it is demonstrated that amplification factors are easily obtained which are more than adequate to explain the observed constrasts in surface brightness between jets and hot spots.

  15. Shock-drift particle acceleration in superluminal shocks - A model for hot spots in extragalactic radio sources

    Energy Technology Data Exchange (ETDEWEB)

    Begelman, M.C.; Kirk, J.G. (Joint Institute for Laboratory Astrophysics, Boulder, CO (USA) Max-Planck-Institut fuer Astrophysik, Garching (Germany, F.R.))

    1990-04-01

    Shock-drift acceleration at relativistic shock fronts is investigated using a fully relativistic treatment of both the microphysics of the shock-drift acceleration and the macrophysics of the shock front. By explicitly tracing particle trajectories across shocks, it is shown how the adiabatic invariance of a particle's magnetic moment breaks down as the upstream shock speed becomes relativistic, and is recovered at subrelativistic velocities. These calculations enable the mean increase in energy of a particle which encounters the shock with a given pitch angle to be calculated. The results are used to construct the downstream electron distribution function in terms of the incident distribution function and the bulk properties of the shock. The synchrotron emissivity of the transmitted distribution is calculated, and it is demonstrated that amplification factors are easily obtained which are more than adequate to explain the observed constrasts in surface brightness between jets and hot spots. 72 refs.

  16. Particle acceleration inside PWN: Simulation and observational constraints with INTEGRAL; Acceleration de particules au sein des vents relativistes de pulsar: simulation et contraintes observationelles avec le satellite INTEGRAL

    Energy Technology Data Exchange (ETDEWEB)

    Forot, M

    2006-12-15

    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.

  17. Low Secondary Electron Yield Carbon Coatings for Electron-cloud Mitigation in Modern Particle Accelerators

    CERN Document Server

    Yin Vallgren, Christina; Calatroni, Sergio; Chiggiato, Paolo; Costa Pinto, Pedro; Marques, Hugo; Neupert, Holger; Taborelli, Mauro; Vollenberg, Wilhelmus; Wevers, Ivo; Yaqub, Kashif

    2010-01-01

    Electron-cloud is one of the main limitations for particle accelerators with positively charged beams of high intensity and short bunch spacing, as the SPS at CERN. The Secondary Electron Yield (SEY) of the inner surface of the vacuum chamber is the main parameter governing the phenomenon. The effect could be eliminated by coating the vacuum chambers with a material of low SEY, which does not require bake-out and is robust against air exposure. For such a purpose amorphous carbon (a-C) coatings were produced by magnetron sputtering of graphite targets. They exhibit maximum SEY between 0.95 and 1.05 after air transfer to the measuring instrument. After 1 month of air exposure the SEY rises by 10 - 20 % of the initial values. Storage in desiccator or by packaging in Al foil makes this increase negligible. The coatings have a similar X-ray photoelectron spectroscopy (XPS) C1s spectrum for a large set of deposition parameters and exhibit an enlarged linewidth compared to HOPG graphite. The static outgassing witho...

  18. An Accelerated Particle Swarm Optimization Algorithm on Parametric Optimization of WEDM of Die-Steel

    Science.gov (United States)

    Muthukumar, V.; Suresh Babu, A.; Venkatasamy, R.; Senthil Kumar, N.

    2015-01-01

    This study employed Accelerated Particle Swarm Optimization (APSO) algorithm to optimize the machining parameters that lead to a maximum Material Removal Rate (MRR), minimum surface roughness and minimum kerf width values for Wire Electrical Discharge Machining (WEDM) of AISI D3 die-steel. Four machining parameters that are optimized using APSO algorithm include Pulse on-time, Pulse off-time, Gap voltage, Wire feed. The machining parameters are evaluated by Taguchi's L9 Orthogonal Array (OA). Experiments are conducted on a CNC WEDM and output responses such as material removal rate, surface roughness and kerf width are determined. The empirical relationship between control factors and output responses are established by using linear regression models using Minitab software. Finally, APSO algorithm, a nature inspired metaheuristic technique, is used to optimize the WEDM machining parameters for higher material removal rate and lower kerf width with surface roughness as constraint. The confirmation experiments carried out with the optimum conditions show that the proposed algorithm was found to be potential in finding numerous optimal input machining parameters which can fulfill wide requirements of a process engineer working in WEDM industry.

  19. Solar energetic particles a modern primer on understanding sources, acceleration and propagation

    CERN Document Server

    Reames, Donald V

    2017-01-01

    This concise primer introduces the non-specialist reader to the physics of solar energetic particles (SEP) and systematically reviews the evidence for the two main mechanisms which lead to the so-called impulsive and gradual SEP events. More specifically, the timing of the onsets, the longitude distributions, the high-energy spectral shapes, the correlations with other solar phenomena (e.g. coronal mass ejections), as well as the all-important elemental and isotopic abundances of SEPs are investigated. Impulsive SEP events are related to magnetic reconnection in solar flares and jets. The concept of shock acceleration by scattering on self-amplified Alfvén waves is introduced, as is the evidence of reacceleration of impulsive-SEP material in the seed population accessed by the shocks in gradual events. The text then develops processes of transport of ions out to an observer. Finally, a new technique to determine the source plasma temperature in both impulsive and gradual events is demonstrated. Last but not ...

  20. Feasibility Study for High Power RF – Energy Recovery in Particle Accelerators

    CERN Document Server

    Betz, Michael

    2010-01-01

    When dealing with particle accelerators, especially in systems with travelling wave structures and low beam loading, a substantial amount of RF power is dissipated in 50Ω termination loads. For the Super Proton Synchrotron (SPS) at Cern this is 69 % of the incident RF power or about 1 MW. Different ideas, making use of that otherwise dissipated power, are presented and their feasibility is reviewed. The most feasible one, utilizing an array of semiconductor based RF/DC modules, is used to create a design concept for energy recovery in the SPS. The modules are required to operate at high power, high efficiency and with low harmonic radiation. Besides the actual RF rectifier, they contain additional components to ensure a graceful degradation of the overall system. Different rectifier architectures and semiconductor devices are compared and the most suitable ones are chosen. Two prototype devices were built and operated with up to 400 W of pulsed RF power. Broadband measurements – capturing all harmonics up ...

  1. Vol.27 - MicroTCA based Platform for advanced particle accelerators diagnostics

    CERN Document Server

    Juszczyk, Bartłomiej

    2014-01-01

    All over the world there are many research centers that are conducting researches with use of particle accelerators. Thanks to various experiments we could better understand surrounding world. But, there are still a lot of unknowns to explore which science needs better instruments. One of these tools are measurement systems. Unfortunately currently used solutions do not provide sufficient performance to satisfy growing needs. This implies the search for new solutions. One of such solution is a modern uTCA architecture. In this document an open source project of a base card (AFC -AMC to FMC carrier board) based on this standard has been described. This card is equipped with two FMC connectors, which allow to connect wide variety of extension cards. In combination with a powerful FPGA device this card is an universal base circuit for variety of projects. Among the others it allows to implement algorithms which are collecting data from fast ADCs and to process these data. Moreover the applied uTCA architecture p...

  2. Nanomedical science and laser-driven particle acceleration: promising approaches in the prethermal regime

    Science.gov (United States)

    Gauduel, Y. A.

    2017-05-01

    A major challenge of spatio-temporal radiation biomedicine concerns the understanding of biophysical events triggered by an initial energy deposition inside confined ionization tracks. This contribution deals with an interdisciplinary approach that concerns cutting-edge advances in real-time radiation events, considering the potentialities of innovating strategies based on ultrafast laser science, from femtosecond photon sources to advanced techniques of ultrafast TW laser-plasma accelerator. Recent advances of powerful TW laser sources ( 1019 W cm-2) and laser-plasma interactions providing ultra-short relativistic particle beams in the energy domain 5-200 MeV open promising opportunities for the development of high energy radiation femtochemistry (HERF) in the prethermal regime of secondary low-energy electrons and for the real-time imaging of radiation-induced biomolecular alterations at the nanoscopic scale. New developments would permit to correlate early radiation events triggered by ultrashort radiation sources with a molecular approach of Relative Biological Effectiveness (RBE). These emerging research developments are crucial to understand simultaneously, at the sub-picosecond and nanometric scales, the early consequences of ultra-short-pulsed radiation on biomolecular environments or integrated biological entities. This innovating approach would be applied to biomedical relevant concepts such as the emerging domain of real-time nanodosimetry for targeted pro-drug activation and pulsed radio-chimiotherapy of cancers.

  3. GPU-accelerated red blood cells simulations with transport dissipative particle dynamics

    Science.gov (United States)

    Blumers, Ansel L.; Tang, Yu-Hang; Li, Zhen; Li, Xuejin; Karniadakis, George E.

    2017-08-01

    Mesoscopic numerical simulations provide a unique approach for the quantification of the chemical influences on red blood cell functionalities. The transport Dissipative Particle Dynamics (tDPD) method can lead to such effective multiscale simulations due to its ability to simultaneously capture mesoscopic advection, diffusion, and reaction. In this paper, we present a GPU-accelerated red blood cell simulation package based on a tDPD adaptation of our red blood cell model, which can correctly recover the cell membrane viscosity, elasticity, bending stiffness, and cross-membrane chemical transport. The package essentially processes all computational workloads in parallel by GPU, and it incorporates multi-stream scheduling and non-blocking MPI communications to improve inter-node scalability. Our code is validated for accuracy and compared against the CPU counterpart for speed. Strong scaling and weak scaling are also presented to characterize scalability. We observe a speedup of 10 . 1 on one GPU over all 16 cores within a single node, and a weak scaling efficiency of 91% across 256 nodes. The program enables quick-turnaround and high-throughput numerical simulations for investigating chemical-driven red blood cell phenomena and disorders.

  4. GPU-accelerated Red Blood Cells Simulations with Transport Dissipative Particle Dynamics.

    Science.gov (United States)

    Blumers, Ansel L; Tang, Yu-Hang; Li, Zhen; Li, Xuejin; Karniadakis, George E

    2017-08-01

    Mesoscopic numerical simulations provide a unique approach for the quantification of the chemical influences on red blood cell functionalities. The transport Dissipative Particles Dynamics (tDPD) method can lead to such effective multiscale simulations due to its ability to simultaneously capture mesoscopic advection, diffusion, and reaction. In this paper, we present a GPU-accelerated red blood cell simulation package based on a tDPD adaptation of our red blood cell model, which can correctly recover the cell membrane viscosity, elasticity, bending stiffness, and cross-membrane chemical transport. The package essentially processes all computational workloads in parallel by GPU, and it incorporates multi-stream scheduling and non-blocking MPI communications to improve inter-node scalability. Our code is validated for accuracy and compared against the CPU counterpart for speed. Strong scaling and weak scaling are also presented to characterizes scalability. We observe a speedup of 10.1 on one GPU over all 16 cores within a single node, and a weak scaling efficiency of 91% across 256 nodes. The program enables quick-turnaround and high-throughput numerical simulations for investigating chemical-driven red blood cell phenomena and disorders.

  5. Particle Acceleration in High-Energy Solar Flares Detected by the Fermi Large Area Telescope

    Science.gov (United States)

    Omodei, N.; Pesce-Rollins, M.; Petrosian, V.; Liu, W.; Rubio da Costa, F.

    2016-12-01

    The Fermi Large Area Telescope (LAT) is the most sensitive instrument ever deployed in space for observing gamma-ray emission above 100 MeV. LAT observations of the active Sun have increased the number of detected solar flares by almost a factor of 10 with respect to previous space observations. We will present an overview of these observations, which include detections of impulsive and sustained emission, extending up to 20 hours in the case of the X-class flare occurred on 2012 March 7. Of particular interest is the first detection of >100 MeV gamma-ray emission from three solar flares whose positions behind the limb were confirmed by the STEREO spacecrafts. These observations sample flares from active regions originating from behind both the eastern and western limbs and present a unique opportunity to diagnose the mechanisms of high-energy emission and particle acceleration in solar flares. We will present the Fermi-LAT, RHESSI and STEREO observations of these flares and discuss how these observations provide constrains on different emission mechanisms.

  6. Estimation of steady-state culture characteristics during acceleration-stats with yeasts

    NARCIS (Netherlands)

    Sluis, van der C.; Westerink, B.H.; Dijkstal, M.M.; Castelein, S.J.; Boxtel, van A.J.B.; Tramper, J.; Wijffels, R.H.

    2001-01-01

    Steady-state culture characteristics are usually determined in chemostat cultivations, which are very time-consuming. In contrast, acceleration-stat (A-stat) cultivations in which the dilution rate is continuously changed with a constant acceleration rate are not so time-consuming, especially at

  7. Volatility and mixing states of ultrafine particles from biomass burning

    Energy Technology Data Exchange (ETDEWEB)

    Maruf Hossain, A.M.M.; Park, Seungho; Kim, Jae-Seok [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Park, Kihong, E-mail: kpark@gist.ac.kr [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Size distribution, volatility, and mixing states of ultrafine particles emitted from rice straw, oak, and pine burning under different burning conditions were investigated. Black-Right-Pointing-Pointer Smoldering combustion emitted larger mode particles in higher numbers than smaller mode particles, while the converse was true for flaming combustion. Black-Right-Pointing-Pointer While the flaming combustion and open burning results imply there is internal mixing of OC and BC, smoldering combustion in rice straw produced ultrafine particles devoid of BC. Black-Right-Pointing-Pointer Mixing state of ultrafine particles from biomass burning can alter the single scattering albedo, and might even change the sign of radiative forcing. - Abstract: Fine and ultrafine carbonaceous aerosols produced from burning biomasses hold enormous importance in terms of assessing radiation balance and public health hazards. As such, volatility and mixing states of size-selected ultrafine particles (UFP) emitted from rice straw, oak, and pine burning were investigated by using volatility tandem differential mobility analyzer (VTDMA) technique in this study. Rice straw combustion produced unimodal size distributions of emitted aerosols, while bimodal size distributions from combustions of oak (hardwood) and pine (softwood) were obtained. A nearness of flue gas temperatures and a lower CO ratio of flaming combustion (FC) to smoldering combustion (SC) were characteristic differences found between softwood and hardwood. SC emitted larger mode particles in higher numbers than smaller mode particles, while the converse was true for FC. Rice straw open burning UFPs exhibited a volatilization behavior similar to that between FC and SC. In addition, internal mixing states were observed for size-selected UFPs in all biomasses for all combustion conditions, while external mixing states were only observed for rice straw combustion. Results for FC and open

  8. Static Metrological Characterization of a Ferrimagnetic Resonance Transducer for Real-Time Magnetic Field Markers in Particle Accelerators

    CERN Document Server

    Arpaia, P; Caspers, F; Golluccio, G; Petrone, C

    2011-01-01

    The metrological characterization of a magnetic field transducer based on ferrimagnetic resonance for real-time markers in particle accelerators is reported. The transducer is designed to measure the magnetic field with an uncertainty of ± 10-5 T. A case study on the new real-time field monitoring system for the CERN accelerators highlighting the performance improvement achieved through the new ferrimagnetic transducer is described. Preliminary experimental results of the characterization for static and dynamic fields are discussed.

  9. Analytical and experimental investigation of the coaxial plasma gun for use as a particle accelerator

    Science.gov (United States)

    Shriver, E. L.

    1972-01-01

    The coaxial plasma accelerator for use as a projectile accelerator is discussed. The accelerator is described physically and analytically by solution of circuit equations, and by solving for the magnetic pressures which are formed by the j cross B vector forces on the plasma. It is shown that the plasma density must be increased if the accelerator is to be used as a projectile accelerator. Three different approaches to increasing plasma density are discussed. When a magnetic field containment scheme was used to increase the plasma density, glass beads of 0.66 millimeter diameter were accelerated to 7 to 8 kilometers per second velocities. Glass beads of smaller diameter were accelerated to more than twice this velocity.

  10. INTERACTING MANY-PARTICLE SYSTEMS OF DIFFERENT PARTICLE TYPES CONVERGE TO A SORTED STATE

    DEFF Research Database (Denmark)

    Kokkendorff, Simon Lyngby; Starke, Jens; Hummel, N.

    2010-01-01

    states are unstable. The models are motivated from physics, chemistry, and biology, and the principal investigations can be useful for many systems with interacting particles or agents. The models match particularly well a system in neuroscience, namely the axonal pathfinding and sorting in the olfactory...

  11. Analytical solutions for transient and steady state beam loading in arbitrary traveling wave accelerating structures

    CERN Document Server

    Lunin, Andrei; Grudiev, Alexej

    2011-01-01

    Analytical solutions are derived for transient and steady state gradient distributions in the travelling wave accelerating structures with arbitrary variation of parameters over the structure length. The results of both the unloaded and beam loaded cases are presented.

  12. Probability distributions of bed load particle velocities, accelerations, hop distances, and travel times informed by Jaynes's principle of maximum entropy

    Science.gov (United States)

    Furbish, David; Schmeeckle, Mark; Schumer, Rina; Fathel, Siobhan

    2016-01-01

    We describe the most likely forms of the probability distributions of bed load particle velocities, accelerations, hop distances, and travel times, in a manner that formally appeals to inferential statistics while honoring mechanical and kinematic constraints imposed by equilibrium transport conditions. The analysis is based on E. Jaynes's elaboration of the implications of the similarity between the Gibbs entropy in statistical mechanics and the Shannon entropy in information theory. By maximizing the information entropy of a distribution subject to known constraints on its moments, our choice of the form of the distribution is unbiased. The analysis suggests that particle velocities and travel times are exponentially distributed and that particle accelerations follow a Laplace distribution with zero mean. Particle hop distances, viewed alone, ought to be distributed exponentially. However, the covariance between hop distances and travel times precludes this result. Instead, the covariance structure suggests that hop distances follow a Weibull distribution. These distributions are consistent with high-resolution measurements obtained from high-speed imaging of bed load particle motions. The analysis brings us closer to choosing distributions based on our mechanical insight.

  13. Charged vector particle tunneling from a pair of accelerating and rotating and 5D gauged super-gravity black holes

    Energy Technology Data Exchange (ETDEWEB)

    Javed, Wajiha; Ali, Riasat [University of Education, Division of Science and Technology, Lahore (Pakistan); Abbas, G. [The Islamia University of Bahawalpur, Department of Mathematics, Bahawalpur (Pakistan)

    2017-05-15

    The aim of this paper is to study the quantum tunneling process for charged vector particles through the horizons of more generalized black holes by using the Proca equation. For this purpose, we consider a pair of charged accelerating and rotating black holes with Newman-Unti-Tamburino parameter and a black hole in 5D gauged super-gravity theory, respectively. Further, we study the tunneling probability and corresponding Hawking temperature for both black holes by using the WKB approximation. We find that our analysis is independent of the particles species whether or not the background black hole geometries are more generalized. (orig.)

  14. openSE: A Systems engineering framework particularly suited to particle accelerator studies and development projects arXiv

    CERN Document Server

    Bonnal, P.; Kershaw, K.; Nicquevert, B.; Baudin, M.; Lari, L.; Cardinal, J. Le

    Particle accelerator projects share many characteristics with industrial projects. However, experience has shown that best practice of industrial project management is not always well suited to particle accelerator projects. Major differences include the number and complexity of technologies involved, the importance of collaborative work, development phases that can last more than a decade, and the importance of telerobotics and remote handling to address future preventive and corrective maintenance requirements due to induced radioactivity, to cite just a few. The openSE framework is a systems engineering and project management framework specifically designed for scientific facilities' systems and equipment studies and development projects. Best practices in project management, in systems and requirements engineering, in telerobotics and remote handling and in radiation safety management were used as sources of inspiration, together with analysis of current practices surveyed at CERN, GSI and ESS.

  15. Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures

    Energy Technology Data Exchange (ETDEWEB)

    Byer, Robert L. [Stanford Univ., CA (United States). Edward L. Ginzton Lab.

    2013-11-07

    The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

  16. Geneva University: Particle Acceleration in supernova remnants and its implications for the origin of galactic cosmic rays

    CERN Multimedia

    Université de Genève

    2012-01-01

    GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92 Wednesday 28 March 2012 SEMINAIRE DE PHYSIQUE CORPUSCULAIRE 11h15 - Science III, Auditoire 1S081 Particle Acceleration in supernova remnants and its implications for the origin of galactic cosmic rays Prof. Pasquale BLASI INAF, Arcetri Observatory, Firenze The process of cosmic ray energization in supernova remnant shocks is described by the theory of non linear diffusive shock acceleration (NLDSA). Such theory is able to describe the acceleration itself, the dynamical reaction of accelerated particles on the shock, and the crucial phenomenon of the magnetic field amplification, the very key to generate high energy cosmic rays. I will illustrate the basic aspects of this theoretical framework, as well as its successes and problems. I will then discuss the observations, in X-rays an...

  17. State-of-the-art superconducting accelerator magnets

    CERN Document Server

    Rossi, L

    2002-01-01

    With the LHC the technology of NbTi-based accelerator magnets has been pushed to the limit. By operating in superfluid helium, magnetic fields in excess of 10 T have been reached in various one meter-long model magnets while full scale magnets, 15 meter-long dipoles, have demonstrated possibility of safe operation in the 8.3-9 tesla range, with the necessary, very tight, field accuracy. The paper reviews the key points of the technology that has permitted the construction of the largest existing superconducting installations (Fermilab, Desy and Brookhaven), highlighting the novelties of the design of the LHC dipoles, quadrupoles and other superconducting magnets. All together the LHC project will need more than 5000 km of fine filament superconducting cables capable of 14 kA @ 10 T, 1.9 K. (13 refs).

  18. Sir John Adams: His Legacy to the World of Particle Accelerators

    CERN Document Server

    CERN. Geneva

    2009-01-01

    John Adams acquired an unrivalled reputation for his leading part in designing and constructing the PS in CERN’s early days. In 1968, and after several years heading a fusion laboratory in the UK, he came back to Geneva to pilot the SPS project to approval and then to direct its construction. At the time of his untimely death in 1984 he had built Europe’s two largest proton accelerators at CERN. He went on, during the second of his terms as DG, to lay the groundwork for the proton-antiproton collider which led to the discovery of the intermediate vector boson. How did someone without any formal academic qualification achieve this? What was the magic behind his leadership? How did he achieve political success with the Member States of CERN in turning the almost hopeless quest for approval of the SPS to CERN’s advantage? How did he view his US counterpart, R. R. Wilson? The speaker, who worked many years alongside Adams, will discuss these questions and speculate on how Sir John Adams might have viewed to...

  19. Sir John Adams - His Legacy to the World of Particle Accelerators

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    John Adams acquired an unrivalled reputation for his leading part in designing and constructing the PS in CERN’s early days. In 1968, and after several years heading a fusion laboratory in the UK, he came back to Geneva to pilot the SPS project to approval and then to direct its construction. At the time of his untimely death in 1984 he had built Europe’s two largest proton accelerators at CERN. He went on, during the second of his terms as DG, to lay the groundwork for the proton-antiproton collider which led to the discovery of the intermediate vector boson. How did someone without any formal academic qualification achieve this? What was the magic behind his leadership? How did he achieve political success with the Member States of CERN in turning the almost hopeless quest for approval of the SPS to CERN’s advantage? How did he view his US counterpart, R. R. Wilson? The speaker, who worked many years alongside Adams, will discuss these questions and speculate on how Sir John Adams might have viewed t...

  20. A Framework for a General Purpose Intelligent Control System for Particle Accelerators. Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Robert Westervelt; Dr. William Klein; Dr. Michael Kroupa; Eric Olsson; Rick Rothrock

    1999-06-28

    Vista Control Systems, Inc. has developed a portable system for intelligent accelerator control. The design is general in scope and is thus configurable to a wide range of accelerator facilities and control problems. The control system employs a multi-layer organization in which knowledge-based decision making is used to dynamically configure lower level optimization and control algorithms.

  1. Dense Plasma Focus Z-pinches for High Gradient Particle Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Tang, V; Adams, M L; Rusnak, B

    2009-07-24

    The final Z-pinch stage of a Dense Plasma Focus (DPF) could be used as a simple, compact, and potentially rugged plasma-based high-gradient accelerator with fields at the 100 MV/m level. In this paper we review previously published experimental beam data that indicate the feasibility of such an DPF-based accelerator, qualitatively discuss the physical acceleration processes in terms of the induced voltages, and as a starting point examine the DPF acceleration potential by numerically applying a self-consistent DPF system model that includes the induced voltage from both macroscopic and instability driven plasma dynamics. Applications to the remote detection of high explosives and a multi-staged acceleration concept are briefly discussed.

  2. Whether and How to Select Inertia and Acceleration of Discrete Particle Swarm Optimization Algorithm: A Study on Channel Assignment

    Directory of Open Access Journals (Sweden)

    Min Jin

    2014-01-01

    Full Text Available There is recently a great deal of interest and excitement in understanding the role of inertia and acceleration in the motion equation of discrete particle swarm optimization (DPSO algorithms. It still remains unknown whether the inertia section should be abandoned and how to select the appropriate acceleration in order for DPSO to show the best convergence performance. Adopting channel assignment as a case study, this paper systematically conducts experimental filtering research on this issue. Compared with other channel assignment schemes, the proposed scheme and the selection of inertia and acceleration are verified to have the advantage to channel assignment in three respects of convergence rate, convergence speed, and the independency of the quality of initial solution. Furthermore, the experimental result implies that DSPO might have the best convergence performance when its motion equation includes an inertia section in a less medium weight, a bigger acceleration coefficient for global-search optimum, and a smaller acceleration coefficient for individual-search optimum.

  3. Quantum teleportation via noisy bipartite and tripartite accelerating quantum states: beyond the single mode approximation

    Science.gov (United States)

    Zounia, M.; Shamirzaie, M.; Ashouri, A.

    2017-09-01

    In this paper quantum teleportation of an unknown quantum state via noisy maximally bipartite (Bell) and maximally tripartite (Greenberger-Horne-Zeilinger (GHZ)) entangled states are investigated. We suppose that one of the observers who would receive the sent state accelerates uniformly with respect to the sender. The interactions of the quantum system with its environment during the teleportation process impose noises. These (unital and nonunital) noises are: phase damping, phase flip, amplitude damping and bit flip. In expressing the modes of the Dirac field used as qubits, in the accelerating frame, the so-called single mode approximation is not imposed. We calculate the fidelities of teleportation, and discuss their behaviors using suitable plots. The effects of noise, acceleration and going beyond the single mode approximation are discussed. Although the Bell states bring higher fidelities than GHZ states, the global behaviors of the two quantum systems with respect to some noise types, and therefore their fidelities, are different.

  4. Acceleration of particles by black hole with gravitomagnetic charge immersed in magnetic field

    OpenAIRE

    Abdujabbarov, Ahmadjon; Tursunov, Arman; Ahmedov, Bobomurat; Kuvatov, Abdulla

    2012-01-01

    The collision of test charged particles in the vicinity of an event horizon of a weakly magnetized non-rotating black hole with gravitomagnetic charge has been studied. The presence of the external magnetic field decreases the innermost stable circular orbits (ISCO) radii of charged particles. The opposite mechanism occurs when there is nonvanishing gravitomagnetic charge. For a collision of charged particle moving at ISCO and the neutral particle falling from infinity the maximal collision e...

  5. Analyzing generalized coherent states for a free particle

    Science.gov (United States)

    Maamache, Mustapha; Khatir, Abderrezak; Lakehal, Halim; Choi, Jeong Ryeol

    2016-08-01

    Despite the didactic importance of a free particle in quantum mechanics, its coherent state analysis has long been untouched. It is only recently that it has been noticed and studied in the semiclassical domain. While the previously known solutions, reported by Bagrov et al. for a free particle, are described using the linear non-Hermitian invariant operator, we show in this work that the general solution of the Schrödinger equation can also be naturally derived using a simpler method based on an Hermitian linear invariant operator. According to this, an exact Gaussian wave function that corresponds to a coherent state solution is obtained. An interpretation for such general quantum solution designated within the Lewis-Riesenfeld framework is provided and, further, quantum-classical correspondence principle for the system is reexamined.

  6. Analyzing generalized coherent states for a free particle.

    Science.gov (United States)

    Maamache, Mustapha; Khatir, Abderrezak; Lakehal, Halim; Choi, Jeong Ryeol

    2016-08-11

    Despite the didactic importance of a free particle in quantum mechanics, its coherent state analysis has long been untouched. It is only recently that it has been noticed and studied in the semiclassical domain. While the previously known solutions, reported by Bagrov et al. for a free particle, are described using the linear non-Hermitian invariant operator, we show in this work that the general solution of the Schrödinger equation can also be naturally derived using a simpler method based on an Hermitian linear invariant operator. According to this, an exact Gaussian wave function that corresponds to a coherent state solution is obtained. An interpretation for such general quantum solution designated within the Lewis-Riesenfeld framework is provided and, further, quantum-classical correspondence principle for the system is reexamined.

  7. Effects of the diffusive acceleration of particles by shock waves in the primordial matter of the solar system

    Science.gov (United States)

    Ustinova, G. K.

    2011-04-01

    The effects of the shock wave diffusive acceleration of particles are considered in the case of formation of isotopic relations of the anomalous Xe- HL component of xenon in relic grains of nanodiamonds in chondrites. It is shown that this component could be formed and captured simultaneously with the nanodiamond synthesis in the conditions of the explosive shock wave propagation from supernova outbursts. The specificity of isotopic composition of Xe- HL is due to the high hardness of the spectrum of nuclear-active particles at the shock wave front and its enrichment with heavy isotopes. The spallogenic nature of both the anomalous and normal components of xenon is ascertained, and the role of the subsequent evolutionary processes in the change of their isotopic systems is shown. Experimental evidence of the formation of the power law spectrum of particles with the spectral index γ ˜ 1 by the supersonic turbulence during the carbon-detonation supernova SnIa explosion is obtained; this perhaps opens new perspectives in studying the problem of the origin of cosmic rays. It is shown that at the stage of free expansion of the explosive shock wave, the degree of compression of the matter at the wave front was σ = 31 (the corresponding Mach number M ˜ 97); this led to a 31-fold increase of the magnetic field as well as of the maximum energy of accelerated particles, so that even the energy of protons reached ˜ 3 × 1015 eV, i.e., the "knee" region.

  8. Asymmetric Bidirectional Controlled Quantum Information Transmission via Seven-Particle Entangled State

    Science.gov (United States)

    Sang, Ming-huang; Nie, Li-ping

    2017-11-01

    We demonstrate that a seven-particle entangled state can be used to realize the deterministic asymmetric bidirectional controlled quantum information transmission by performing only Bell-state measurement and two-particle projective measurement and single-particle measurement. In our protocol, Alice can teleport an arbitrary unknown single-particle state to Bob and at the same time Bob can remotely prepare an arbitrary known two-particle state for Alice via the control of the supervisor Charlie.

  9. Radiation Protection Studies for Medical Particle Accelerators using Fluka Monte Carlo Code.

    Science.gov (United States)

    Infantino, Angelo; Cicoria, Gianfranco; Lucconi, Giulia; Pancaldi, Davide; Vichi, Sara; Zagni, Federico; Mostacci, Domiziano; Marengo, Mario

    2017-04-01

    Radiation protection (RP) in the use of medical cyclotrons involves many aspects both in the routine use and for the decommissioning of a site. Guidelines for site planning and installation, as well as for RP assessment, are given in international documents; however, the latter typically offer analytic methods of calculation of shielding and materials activation, in approximate or idealised geometry set-ups. The availability of Monte Carlo (MC) codes with accurate up-to-date libraries for transport and interaction of neutrons and charged particles at energies below 250 MeV, together with the continuously increasing power of modern computers, makes the systematic use of simulations with realistic geometries possible, yielding equipment and site-specific evaluation of the source terms, shielding requirements and all quantities relevant to RP at the same time. In this work, the well-known FLUKA MC code was used to simulate different aspects of RP in the use of biomedical accelerators, particularly for the production of medical radioisotopes. In the context of the Young Professionals Award, held at the IRPA 14 conference, only a part of the complete work is presented. In particular, the simulation of the GE PETtrace cyclotron (16.5 MeV) installed at S. Orsola-Malpighi University Hospital evaluated the effective dose distribution around the equipment; the effective number of neutrons produced per incident proton and their spectral distribution; the activation of the structure of the cyclotron and the vault walls; the activation of the ambient air, in particular the production of 41Ar. The simulations were validated, in terms of physical and transport parameters to be used at the energy range of interest, through an extensive measurement campaign of the neutron environmental dose equivalent using a rem-counter and TLD dosemeters. The validated model was then used in the design and the licensing request of a new Positron Emission Tomography facility. © The Author 2016

  10. Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, S. A.; Nagaitsev, S.; Valishev, A.

    2017-04-01

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

  11. Squeezed States and Particle Production in High Energy Collisions

    Science.gov (United States)

    Bambah, Bindu A.

    1996-01-01

    Using the 'quantum optical approach' we propose a model of multiplicity distributions in high energy collisions based on squeezed coherent states. We show that the k-mode squeezed coherent state is the most general one in describing hadronic multiplicity distributions in particle collision processes, describing not only p(bar-p) collisions but e(+)e(-), vp and diffractive collisions as well. The reason for this phenomenological fit has been gained by working out a microscopic theory in which the squeezed coherent sources arise naturally if one considers the Lorentz squeezing of hadrons and works in the covariant phase space formalism.

  12. Next-generation solid-state detectors for charged particle spectroscopy

    Science.gov (United States)

    Ogasawara, K.; Livi, S. A.; Allegrini, F.; Broiles, T. W.; Dayeh, M. A.; Desai, M. I.; Ebert, R. W.; Llera, K.; Vines, S. K.; McComas, D. J.

    2016-07-01

    The performance of silicon avalanche photodiodes (APDs) and single crystal chemical vapor deposit diamond detectors (DDs) is reviewed in comparison with conventional silicon-based solid-state detectors (SSDs) from the perspective of space plasma applications. Although the low-energy threshold and the energy resolution are equivalent to SSDs, DDs offer a high radiation tolerance and very low leakage currents due to a wider band gap than silicon. In addition, DDs can operate at higher temperatures, are insensitive to light (>226 nm), and are capable of timing analysis due to the higher intrinsic carrier mobility. APDs also offer several advantageous features. Specifically, APDs have a lower energy threshold (linear response due to a strong electric field causing signal amplifications within the detector. Therefore, APDs can be used to detect lower energy particles, covering a larger portion of the energy spectrum than conventional SSDs. Further, the strong internal electric field gives them a subnanosecond response time by the charge mobility saturation, allowing them to make precise timing measurements of ions. These novel detector techniques can be potentially applied to improve the measurements of suprathermal particles, whose energies lie between typical ranges of conventional sensors for low-energy plasmas and energetic particles. Although the origin and evolution of the suprathermal particles are the key to understanding the acceleration and heating processes in space plasma, they are not well understood due to the technical difficulties of making the measurement.

  13. The use of bulk states to accelerate the band edge statecalculation of a semiconductor quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Vomel, Christof; Tomov, Stanimire Z.; Wang, Lin-Wang; Marques,Osni A.; Dongarra, Jack J.

    2006-05-10

    We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations.

  14. Design and construction of multi-port solid state structure for the Rhodotron accelerator

    Science.gov (United States)

    Poursaleh, A. M.; Jabbari, I.; Khalafi, H.

    2017-04-01

    RF generation and method used for coupling power to the acceleration cavity are important issues in the RF accelerators. In this study, a high power vacuum tube was replaced with several medium power solid state amplifiers coupled through a multi-port structure in the Rhodotron-TT200 accelerator. To this end, a multi-port structure was implemented on a small aluminum model cavity for 1 to 9 ports and all main parameters affecting return loss, quality factor, coupling coefficient and RF power were investigated by calculation, simulation and experimental tests. Then, three 20 kW solid state amplifiers were designed and constructed. The outputs of these amplifiers were coupled to the Rhodotron acceleration cavity by three input ports based on the results obtained from the model cavity for generation of 5 MeV electron beam. In this method, several smaller amplifiers were used instead of a single high power amplifier. As such, acceleration cavity plays the role of power combiner in addition to its primary role and there is no need to a high power combiner. The results showed that the number of ports, port positions, angle between ports and phase of input signals, significantly affect the acceleration electrical field in the cavity. Also, experimental tests revealed that three constructed RF power supplies are enough for the generation of 5 MeV electron beam in the Rhodotron accelerator. Considering the advantages of the solid state amplifiers, application of multi-port structure and solid state amplifiers could be expanded in the industrial electron accelerators.

  15. Measurement and quality control of a new generation of particle accelerator and detectors Geological and thermal influence on the particle beam position

    CERN Document Server

    Krauter, L

    2004-01-01

    At CERN (European Organization for Nuclear Research, Geneva, Switzerland) the most powerful particle collider in the world is under construction. It will be the first time that an accelerator with a diameter of 9 km runs totally on superconducting magnets. Because of the large size of this machine, the influence of the movement from the plate tectonic is not negligible for the alignment of the magnets. Another negative influence on the precision of the centre of the magnetic field is the warping of the magnet caused by the thermal contraction during the cooling down process from room temperature to the operating temperature of 1.9 K.

  16. Particle acceleration in the core and annular regions of pulsar magnetospheres

    Science.gov (United States)

    Lee, K.; Qiao, G.; Xu, R.

    It is realized recently that the high altitude acceleration are very important for the gamma -ray radiation from pulsars Qiao et al 2004 Dyks and Rudak 2003 There is already some work on the physical foundation of this high altitude acceleration Muslimov and Harding 2004 In this presentation we will demonstrate that the open magnetic field line region should be separated into two parts the annular and the core regions It will be shown that the annular region is important for the high altitude acceleration It is found that the annular cap region is an important plasma source and the secondary pairs can gain higher acceleration within the annular region This offers physical foundations for the geometrical gamma -ray radiative models Qiao et al 2004 Dyks and Rudak 2003

  17. Physical conditions for conducting radiobiological experiments in beams of accelerated particles with high linear energy transfer

    Science.gov (United States)

    Kudryashov, Y. I.; Marennyy, A. M.; Popov, V. I.; Aykhorn, K.; Ertsgreber, G.

    1974-01-01

    The design and construction of an accelerator to conduct radiobiological experiments is reported that uses aluminum filters to control the accelerated ion beam while preserving its stability, and a vacuum chamber to conduct the ion beam with the help of a collector through a lavsan exit port to the target. Depth distribution of the absorbed dose from a monodirectional ion beam is practically completely represented by the change in the energy spectrum of the biological object.

  18. Volatile properties of particles emitted by compressed natural gas and diesel buses during steady-state and transient driving modes.

    Science.gov (United States)

    Jayaratne, E R; Meyer, N K; Ristovski, Z D; Morawska, L

    2012-01-03

    Volatile properties of particle emissions from four compressed natural gas (CNG) and four diesel buses were investigated under steady-state and transient driving modes on a chassis dynamometer. The exhaust was diluted utilizing a full-flow continuous volume sampling system and passed through a thermodenuder at controlled temperature. Particle number concentration and size distribution were measured with a condensation particle counter and a scanning mobility particle sizer, respectively. We show that while almost all the particles emitted by the CNG buses were in the nanoparticle size range, at least 85% and 98% were removed at 100 and 250 °C, respectively. Closer analysis of the volatility of particles emitted during transient cycles showed that volatilization began at around 40 °C, with the majority occurring by 80 °C. Particles produced during hard acceleration from rest exhibited lower volatility than those produced during other times of the cycle. On the basis of our results and the observation of ash deposits on the walls of the tailpipes, we suggest that these nonvolatile particles were composed mostly of ash from lubricating oil. Heating the diesel bus emissions to 100 °C removed ultrafine particle numbers by 69-82% when a nucleation mode was present and just 18% when it was not.

  19. Ferroelectric hollow particles obtained by solid-state reaction

    Energy Technology Data Exchange (ETDEWEB)

    Buscaglia, Maria Teresa; Buscaglia, Vincenzo; Viviani, Massimo; Nanni, Paolo [Institute of Energetics and Interphases, National Research Council, Via De Marini 6, I-16149 Genoa (Italy); Dondero, Giovanni [Institute for Macromolecular Studies, National Research Council, Via De Marini 6, I-16149 Genoa (Italy); Roehrig, Serge; Ruediger, Andreas [Institute of Solid State Research, Centre of Nanoelectronic Systems for Information Technology, Research Centre Juelich, 52425 Juelich (Germany)], E-mail: v.buscaglia@ge.ieni.cnr.it

    2008-06-04

    Hollow particles of barium titanate were obtained by a two-step process combining colloidal chemistry and solid-state reaction. BaCO{sub 3} crystals (size {approx}1 {mu}m) suspended in a peroxy-Ti(IV) aqueous solution were coated with an amorphous TiO{sub 2} shell using a precipitation process. Calcination of the BaCO{sub 3}-TiO{sub 2} core-shell particles at 700 deg. C resulted in the formation of BaTiO{sub 3} hollow particles (shell thickness of {approx}70 nm) which retain the morphology of the BaCO{sub 3} crystals. Formation of the cavity occurs because out-diffusion of the core phase is much faster than in-diffusion of the shell material. X-ray diffraction (XRD) and Raman spectroscopy indicate that the hollow particles possess a tetragonal ferroelectric structure with axial ratio c/a = 1.005. Piezoresponse force microscopy has shown strong piezoactivity and 180 deg. ferroelectric domains. The process described provides a general route to fabricate hollow ferroelectric structures of several compounds.

  20. Ferroelectric hollow particles obtained by solid-state reaction.

    Science.gov (United States)

    Buscaglia, Maria Teresa; Buscaglia, Vincenzo; Viviani, Massimo; Dondero, Giovanni; Röhrig, Serge; Rüdiger, Andreas; Nanni, Paolo

    2008-06-04

    Hollow particles of barium titanate were obtained by a two-step process combining colloidal chemistry and solid-state reaction. BaCO(3) crystals (size ≈1 µm) suspended in a peroxy-Ti(IV) aqueous solution were coated with an amorphous TiO(2) shell using a precipitation process. Calcination of the BaCO(3)@TiO(2) core-shell particles at 700 °C resulted in the formation of BaTiO(3) hollow particles (shell thickness of ≈70 nm) which retain the morphology of the BaCO(3) crystals. Formation of the cavity occurs because out-diffusion of the core phase is much faster than in-diffusion of the shell material. X-ray diffraction (XRD) and Raman spectroscopy indicate that the hollow particles possess a tetragonal ferroelectric structure with axial ratio c/a = 1.005. Piezoresponse force microscopy has shown strong piezoactivity and 180° ferroelectric domains. The process described provides a general route to fabricate hollow ferroelectric structures of several compounds.

  1. Neutron-decay Protons from Solar Flares as Seed Particles for CME-shock Acceleration in the Inner Heliosphere

    Science.gov (United States)

    Murphy, Ronald J.; Ko, Yuan-Kuen

    2017-09-01

    The protons in large solar energetic particle events are accelerated in the inner heliosphere by fast shocks produced by coronal mass ejections. Unless there are other sources, the protons these shocks act upon would be those of the solar wind (SW). The efficiency of the acceleration depends on the kinetic energy of the protons. For a 2000 km s-1 shock, the most effective proton energies would be 30-100 keV; I.e., within the suprathermal tail component of the SW. We investigate one possible additional source of such protons: those resulting from the decay of solar-flare-produced neutrons that escape from the Sun into the low corona. The neutrons are produced by interactions of flare-accelerated ions with the solar atmosphere. We discuss the production of low-energy neutrons in flares and their decay on a interplanetary magnetic field line near the Sun. We find that even when the flaring conditions are optimal, the 30-100 keV neutron-decay proton density produced by even a very large solar flare would be only about 10% of that of the 30-100 keV SW suprathermal tail. We discuss the implication of a seed-particle source of more frequent, small flares.

  2. Accelerators of particles and nuclear energy: the challenge of reliability; Aceleradores de partaculas y energia nuclear: el desafio de la fiabilidad

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Ramos, P.

    2011-07-01

    The use of particle accelerators for high energy industrial technology involves subjecting the reliability requirements more stringent than those that exist and become the main objective from the early stages of design.

  3. Accelerating science and innovation societal benefits of European research in Particle Physics

    CERN Multimedia

    Radford, Tim; Jakobsson, Camilla; Marsollier, Arnaud; Mexner, Vanessa; O'Connor, Terry

    2013-01-01

    The story so far. Collaborative research in particle physics. The lesson for Europe: co-operation pays. Medicine and life sciences. The body of knowledge: particles harnessed for health. Energy and the environment. Think big: save energy and clean up the planet. Communication and new technologies. The powerhouse of invention. Society and skills. Power to the people. The European Strategy for Particle Physics. Update 2013.

  4. The Atomki accelerator center

    Science.gov (United States)

    Vajda, I.; Fülöp, Zs.; Biri, S.

    2017-06-01

    Particle accelerators are the driving forces of nuclear physics laboratories and MTA Atomki, the Institute for Nuclear Research of the Hungarian Academy of Sciences is no exception. The Atomki Accelerator Center (AAC) incorporates several low-energy charged-particle accelerators, offering the possibility of choosing ions with various charge states, energies and beam intensities. Currently, the AAC has six main facilities: a cyclotron (K=20), two Van de Graaff accelerators (1 MV, 5 MV), an ECR ion source, an electromagnetic isotope separator and a 2 MV Tandetron installed in 2015. The accelerators, spanning a range of beam energies from 50 eV to 27 MeV, have been designed for a broad range of research projects and applications in various fields - mainly in nuclear and atomic physics, materials science, environmental research and archaeology. The structure of the laboratory with a short description of the most important topics, education and outreach activities are presented.

  5. gEMpicker: a highly parallel GPU-accelerated particle picking tool for cryo-electron microscopy

    Science.gov (United States)

    2013-01-01

    Background Picking images of particles in cryo-electron micrographs is an important step in solving the 3D structures of large macromolecular assemblies. However, in order to achieve sub-nanometre resolution it is often necessary to capture and process many thousands or even several millions of 2D particle images. Thus, a computational bottleneck in reaching high resolution is the accurate and automatic picking of particles from raw cryo-electron micrographs. Results We have developed “gEMpicker”, a highly parallel correlation-based particle picking tool. To our knowledge, gEMpicker is the first particle picking program to use multiple graphics processor units (GPUs) to accelerate the calculation. When tested on the publicly available keyhole limpet hemocyanin dataset, we find that gEMpicker gives similar results to the FindEM program. However, compared to calculating correlations on one core of a contemporary central processor unit (CPU), running gEMpicker on a modern GPU gives a speed-up of about 27 ×. To achieve even higher processing speeds, the basic correlation calculations are accelerated considerably by using a hierarchy of parallel programming techniques to distribute the calculation over multiple GPUs and CPU cores attached to multiple nodes of a computer cluster. By using a theoretically optimal reduction algorithm to collect and combine the cluster calculation results, the speed of the overall calculation scales almost linearly with the number of cluster nodes available. Conclusions The very high picking throughput that is now possible using GPU-powered workstations or computer clusters will help experimentalists to achieve higher resolution 3D reconstructions more rapidly than before. PMID:24144335

  6. Loss-proof self-accelerating beams and their use in non-paraxial manipulation of particles' trajectories.

    Science.gov (United States)

    Schley, Ran; Kaminer, Ido; Greenfield, Elad; Bekenstein, Rivka; Lumer, Yaakov; Segev, Mordechai

    2014-10-30

    Self-accelerating beams--shape-preserving bending beams--are attracting great interest, offering applications in many areas such as particle micromanipulation, microscopy, induction of plasma channels, surface plasmons, laser machining, nonlinear frequency conversion and electron beams. Most of these applications involve light-matter interactions, hence their propagation range is limited by absorption. We propose loss-proof accelerating beams that overcome linear and nonlinear losses. These beams, as analytic solutions of Maxwell's equations with losses, propagate in absorbing media while maintaining their peak intensity. While the power such beams carry decays during propagation, the peak intensity and the structure of their main lobe region are maintained over large distances. We use these beams for manipulation of particles in fluids, steering the particles to steeper angles than ever demonstrated. Such beams offer many additional applications, such as loss-proof self-bending plasmons. In transparent media these beams show exponential intensity growth, which facilitates other novel applications in micromanipulation and ignition of nonlinear processes.

  7. Biological Effects of Particles with Very High Energy Deposition on Mammalian Cells Utilizing the Brookhaven Tandem Van de Graaff Accelerator

    Science.gov (United States)

    Saha, Janapriya; Cucinotta, Francis A.; Wang, Minli

    2013-01-01

    High LET radiation from GCR (Galactic Cosmic Rays) consisting mainly of high charge and energy (HZE) nuclei and secondary protons and neutrons, and secondaries from protons in SPE (Solar Particle Event) pose a major health risk to astronauts due to induction of DNA damage and oxidative stress. Experiments with high energy particles mimicking the space environment for estimation of radiation risk are being performed at NASA Space Radiation Laboratory at BNL. Experiments with low energy particles comparing to high energy particles of similar LET are of interest for investigation of the role of track structure on biological effects. For this purpose, we report results utilizing the Tandem Van de Graaff accelerator at BNL. The primary objective of our studies is to elucidate the influence of high vs low energy deposition on track structure, delta ray contribution and resulting biological responses. These low energy ions are of special relevance as these energies may occur following absorption through the spacecraft and shielding materials in human tissues and nuclear fragments produced in tissues by high energy protons and neutrons. This study will help to verify the efficiency of these low energy particles and better understand how various cell types respond to them.

  8. Particle Acceleration in Mildly Relativistic Shearing Flows: The Interplay of Systematic and Stochastic Effects, and the Origin of the Extended High-energy Emission in AGN Jets

    Science.gov (United States)

    Liu, Ruo-Yu; Rieger, F. M.; Aharonian, F. A.

    2017-06-01

    The origin of the extended X-ray emission in the large-scale jets of active galactic nuclei (AGNs) poses challenges to conventional models of acceleration and emission. Although electron synchrotron radiation is considered the most feasible radiation mechanism, the formation of the continuous large-scale X-ray structure remains an open issue. As astrophysical jets are expected to exhibit some turbulence and shearing motion, we here investigate the potential of shearing flows to facilitate an extended acceleration of particles and evaluate its impact on the resultant particle distribution. Our treatment incorporates systematic shear and stochastic second-order Fermi effects. We show that for typical parameters applicable to large-scale AGN jets, stochastic second-order Fermi acceleration, which always accompanies shear particle acceleration, can play an important role in facilitating the whole process of particle energization. We study the time-dependent evolution of the resultant particle distribution in the presence of second-order Fermi acceleration, shear acceleration, and synchrotron losses using a simple Fokker-Planck approach and provide illustrations for the possible emergence of a complex (multicomponent) particle energy distribution with different spectral branches. We present examples for typical parameters applicable to large-scale AGN jets, indicating the relevance of the underlying processes for understanding the extended X-ray emission and the origin of ultrahigh-energy cosmic rays.

  9. States leverage telepsychiatry solutions to ease ED crowding, accelerate care.

    Science.gov (United States)

    2015-02-01

    Many states are having success turning to telepsychiatry-based solutions to connect mental health patients with needed care while also decompressing crowded EDs. Just one year into a statewide telepsychiatry initiative in North Carolina (NC-STeP), administrators say the approach has saved as much as $7 million, and hospital demand for the service is higher than anticipated. In Texas, mental health emergency centers (MHEC) that use telepsychiatry to connect patients in rural areas with needed psychiatric care are freeing up EDs to focus on medical care. In just 11 months, 91 North Carolina hospitals have at least started the process to engage in NC-STeP. Much of the savings from NC-STeP come from involuntary commitment orders being overturned as a result of the telepsychiatry consults, reducing the need for expensive inpatient care. Implementing NC-STeP has involved multiple hurdles including credentialing difficulties and technical/firewall challenges. The Texas model provides 24/7 availability of psychiatrists via telemedicine through a network of MHECs. In-person staff at the MHECs perform basic screening tests and blood draws so that medical clearance can be achieved without the need for an ED visit in most cases. Funding for the MHECs comes from the state, hospitals in the region, and local governmental authorities that reap savings or benefits from the initiative.

  10. Steady-State Anderson Accelerated Coupling of Lattice Boltzmann and Navier–Stokes Solvers

    KAUST Repository

    Atanasov, Atanas

    2016-10-17

    We present an Anderson acceleration-based approach to spatially couple three-dimensional Lattice Boltzmann and Navier–Stokes (LBNS) flow simulations. This allows to locally exploit the computational features of both fluid flow solver approaches to the fullest extent and yields enhanced control to match the LB and NS degrees of freedom within the LBNS overlap layer. Designed for parallel Schwarz coupling, the Anderson acceleration allows for the simultaneous execution of both Lattice Boltzmann and Navier–Stokes solver. We detail our coupling methodology, validate it, and study convergence and accuracy of the Anderson accelerated coupling, considering three steady-state scenarios: plane channel flow, flow around a sphere and channel flow across a porous structure. We find that the Anderson accelerated coupling yields a speed-up (in terms of iteration steps) of up to 40% in the considered scenarios, compared to strictly sequential Schwarz coupling.

  11. Evaluation and redesign of radiation shielding in a radionuclide production facility at a particle accelerator / Onalenna Kegopotsemang

    OpenAIRE

    Kegopotsemang, Onalenna

    2004-01-01

    iThemba LABS is a particle accelerator facility housing a radionuclide production facility that uses a 66 MeV proton beam to produce radionuclides for medical and industrial use. Ionising radiation is produced by a variety of sources at Themba LABS. Ionising is a health hazard. High doses can cause acute radiation syndrome, i.e. "radiation sickness". Lower doses cannot cause acute symptom, but carry a risk of radiation-related cancer. Ionising radiation is also detrimental to materials, and c...

  12. Study of particle transport in a high power spallation target for an accelerator-driven transmutation system

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, Nikhil Vittal

    2013-01-31

    AGATE is a project envisaged to demonstrate the feasibility of transmutation in a gas (helium) cooled accelerator-driven system using solid spallation target. Development of the spallation target module and assessing its safety aspects are studied in this work. According to the AGATE concept parameters, 600 MeV protons are delivered on to the segmented tungsten spallation target. The Monte Carlo toolkit Geant4 has been used in the simulation of particle transport. Binary cascade is used to simulate intra-nuclear cascades, along with the G4NDL neutron data library for low energy neutrons (<20 MeV).

  13. Particle accelerators and nuclear energy: the challenge of reliability; Acceleradores de particulas y energia nuclear: el desafio de la fiabilidad

    Energy Technology Data Exchange (ETDEWEB)

    Brucker, R.; Fernandez Ramos, P.

    2011-07-01

    High energy particle accelerators, that used to serve a purpose only in fundamental research, will soon be used in industrial applications of nuclear energy. In this context, they will be submitted to unprecedented (as far as such machines are concerned) reliability requirements. In order to meet them, reliability studies need to be carried out. This article describes the experience gained by Empresarios Agrupados in that field (with the Eurotrans and Ifmif projects) and presents their future activities in the framework of the Myrrha project, that is aimed at building the first ADS reactor in the world. (Author)

  14. Accelerated Particle Composition and Energetics and Ambient Abundances from Gamma-Ray Spectroscopy of the 1991 June 4 Solar Flare

    Science.gov (United States)

    1997-01-01

    give a physical value for the 3He/H ratio. We tested whether this could be due to a hardening of the accelerated particle spectrum at high energies as...models the neutron-capture line decay time with a simple exponential. Physical values could only be obtained if the average density at the neutron...Yoshikoshi, T. 1992, Astroparticle Phys., 1, 27 Chupp, E. L. 1987, Phys. Scripta, T18, 5 DelSignore, K. W. 1995, Ph.D. thesis, Case Western Reserve

  15. Mixing states of soot and BC particles measured using transmission electron microscope (TEM) and single particle soot photometer (SP2)

    Science.gov (United States)

    Adachi, K.; Moteki, N.; Kondo, Y.; Igarashi, Y.

    2013-12-01

    Soot and black carbon (BC) aerosol particles largely affect global climate and commonly mix with other materials such as organic materials and sulfate. Their optical, chemical, and hygroscopic properties largely depend on the coatings. A transmission electron microscope (TEM) and a single particle soot photometer (SP2) measure mixing states of soot particles and BC, respectively, with different approaches. Here we use the term 'soot' for TEM and 'BC' for SP2 analyses because they have different definitions although soot and BC would be essentially the same material. TEM visually shows mixing states of each particle, i.e., since soot and its coating have different interferences to an electron beam, we can directly observe how soot and its coating mix within particles. SP2, on the other hand, measures aerosol light scattering and BC incandescence signals and analyzes the entire particle sizes and the amounts of BC if internally mixed. SP2 also has a capability to distinguish BC in the center of other materials and on that on the surface. Although TEM directly observes particle configurations particle by particle, it is off-line measurements and analyzes limited particles. SP2 does on-line analysis and thus measures ambient particles continuously, but it needs interpretations to evaluate the mixing states. In this study, we aim to compare the both instruments and use their advantages for better approaches to measure the mixing states of soot and BC particles. Here, we collected aerosol samples from the metropolitan area of Tokyo, Japan during August 2012. TEM aerosol samples and SP2 measurements were done simultaneously. The results show good agreements between soot and BC mass and the changes of the mixing states. We will also discuss the diurnal changes of the mixing states from the data obtained using TEM and SP2. The knowledge of detailed soot and BC mixing states will contribute to accurate evaluations of the global climate modeling.

  16. Strongly Localized Image States of Spherical Graphitic Particles

    Directory of Open Access Journals (Sweden)

    Godfrey Gumbs

    2014-01-01

    Full Text Available We investigate the localization of charged particles by the image potential of spherical shells, such as fullerene buckyballs. These spherical image states exist within surface potentials formed by the competition between the attractive image potential and the repulsive centripetal force arising from the angular motion. The image potential has a power law rather than a logarithmic behavior. This leads to fundamental differences in the nature of the effective potential for the two geometries. Our calculations have shown that the captured charge is more strongly localized closest to the surface for fullerenes than for cylindrical nanotube.

  17. Stationary bound states of Dirac particles in collapsar's fields

    Science.gov (United States)

    Gorbatenko, M. V.; Neznamov, V. P.

    2012-03-01

    For a Schwarzschild gravitational field by use of a self-conjugate Hamiltonian with a flat scalar product in a wide interval of gravitational constant stationary non-decaiing in time bound states for spin 1/2 elementary particles have been obtained for a first time. To obtain a discrete energies spectrum a boundary condition was introduced, corresponding to null current density of Dirac partciles near the events horizon. The results obtained could lead to reevaluation of some existing representations of the standart cosmological model, related with the Universe's evolution and with collapsars interactions with encountering media.

  18. Improvement in the Design of Metal-Ceramic High Voltage Feedthroughs for use in High Energy Particle Accelerators

    CERN Document Server

    Weterings, W

    1999-01-01

    Large high-voltage devices operate in particle accelerators to steer charged particles in the desired direction. Solid and hollow rods of sintered alumina are used as insulating supports and high-voltage feedthroughs to power the electrodes of these electrostatic systems. The performance of the systems is often limited by voltage breakdown along the surface of the ceramic insulator (so-called surface flashover) or discharge between feedthrough and vacuum tank, which can lead to significant disruptions in terms of overall machine efficiency. Available results on the influence of the mechanical preparation, thermal history and particular cleaning techniques on commercially obtainable alumina samples have been studied in order to investigate possibilities for better preparation methodology of the insulating supports. Also the influence of the relative position of the feedthrough inside the vacuum tank on the high-voltage breakdown behaviour has been studied. This paper describes the theoretical and practical bac...

  19. DIPAC 2005 7. European workshop on beam diagnostics and instrumentation for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Accelerators can not be improved without the development of adequate beam instruments and diagnostic tools. This year this statement is particularly right: a lot of contributions are dedicated to beam monitoring and to the design of new beam monitors based on original technologies. This document gathers about 100 contributions.

  20. GPU accelerated Discrete Element Method (DEM) molecular dynamics for conservative, faceted particle simulations

    Energy Technology Data Exchange (ETDEWEB)

    Spellings, Matthew [Chemical Engineering, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 (United States); Biointerfaces Institute, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 (United States); Marson, Ryan L. [Materials Science & Engineering, University of Michigan, 2300 Hayward St., Ann Arbor, MI 48109 (United States); Biointerfaces Institute, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 (United States); Anderson, Joshua A. [Chemical Engineering, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 (United States); Biointerfaces Institute, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 (United States); Glotzer, Sharon C., E-mail: sglotzer@umich.edu [Chemical Engineering, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 (United States); Materials Science & Engineering, University of Michigan, 2300 Hayward St., Ann Arbor, MI 48109 (United States); Biointerfaces Institute, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 (United States)

    2017-04-01

    Faceted shapes, such as polyhedra, are commonly found in systems of nanoscale, colloidal, and granular particles. Many interesting physical phenomena, like crystal nucleation and growth, vacancy motion, and glassy dynamics are challenging to model in these systems because they require detailed dynamical information at the individual particle level. Within the granular materials community the Discrete Element Method has been used extensively to model systems of anisotropic particles under gravity, with friction. We provide an implementation of this method intended for simulation of hard, faceted nanoparticles, with a conservative Weeks–Chandler–Andersen (WCA) interparticle potential, coupled to a thermodynamic ensemble. This method is a natural extension of classical molecular dynamics and enables rigorous thermodynamic calculations for faceted particles.

  1. Accelerated Transport of Particles in Confined Channels with a High Roughness Amplitude.

    Science.gov (United States)

    Ranchon, Hubert; Cacheux, Jean; Reig, Benjamin; Liot, Olivier; Teerapanich, Pattamon; Leichlé, Thierry; Joseph, Pierre; Bancaud, Aurélien

    2018-01-30

    We investigate the pressure-driven transport of particles 200 or 300 nm in diameter in shallow microfluidic channels ∼1 μm in height with a bottom wall characterized by a high roughness amplitude of ∼100 nm. This study starts with the description of an assay to generate cracks in hydrophilic thin polymer films together with a structural characterization of these corrugations. Microfluidic chips of variable height are then assembled on top of these rough surfaces, and the transport of particles is assessed by measuring the velocity distribution function for a set of pressure drops. We specifically detect anomalous transport properties for rough surfaces. The maximum particle velocity at the centerline of the channel is comparable to that obtained with smooth surfaces, but the average particle velocity increases nonlinearly with the flow rate. We suggest that the change in the boundary condition at the rough wall is not sufficient to account for our data and that the occurrence of contacts between the particle and the surface transports the particle away from the wall and speeds up its motion. We finally draw perspectives for the separation by field-flow fractionation.

  2. Spatial Distribution of Element Abundances and Ionization States in Solar Energetic-Particle Events

    Science.gov (United States)

    Reames, Donald V.

    2017-08-01

    We have studied the spatial and temporal distribution of abundances of chemical elements in large "gradual" solar energetic-particle (SEP) events, and especially the source plasma temperatures, derived from those abundances, using measurements from the Wind and Solar TErrestrial RElations Observatory (STEREO) spacecraft, widely separated in solar longitude. A power-law relationship between abundance enhancements and mass-to-charge ratios [A/Q] of the ions can be used to determine Q-values and source plasma temperatures at remote spacecraft with instruments that were not designed for charge-state measurements. We search for possible source variations along the accelerating shock wave, finding one clear case where the accelerating shock wave appears to dispatch ions from 3.2± 0.8 MK plasma toward one spacecraft and those from 1.6± 0.2 MK plasma toward another, 116∘ away. The difference persists for three days and then fades away. Three other SEP events show less-extreme variation in source temperatures at different spacecraft, in one case observed over 222∘ in longitude. This initial study shows how the power-law relation between abundance enhancements and ion A/Q-values provides a new technique to determine Q and plasma temperatures in the seed population of SEP ions over a broad region of space using remote spacecraft with instruments that were not originally designed for measurements of ionization states.

  3. Internal geometry of n-body systems and one-particle states

    Energy Technology Data Exchange (ETDEWEB)

    Chylinski, Z.; Obryk, E. [Institute of Nuclear Physics, Cracow (Poland)

    1993-07-01

    The nonrelativistic (NR) shell model of nuclei based on one-particle states results in a ``surprise`` pointed out by Peierls, which consist in the accelerated motion of ``free`` nucleus impossible to eliminate by the standard perturbation theory. The NR mechanics solves the puzzle by indicating a geometrically privileged position of the absolute configuration space generated by the three-dimensional space R{sub 3} spanned on the relative coordinate ``y``. This converts the ``n-body`` problem into the ``(n-1) -relational-object`` problem with absolute (frame-independent) structures. The relativistic kinematics shows that the Galilean-absolute characteristic of the system obtained in the R{sub 3} x......x R{sub 3} ( (n-1) times) configuration space remain absolute in the true Minkowski spacetime L{sub 4} of measurement. However, this necessitates abandoning the classical L{sub 4}-eventism as the first metrical continuum of physics. (author). 16 refs.

  4. A Study on the regulation improvement through the analysis of domestic and international categorization and licensing process for large particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Gwon, Da-Yeong; Jeon, Yeo-Ryeong; Kim, Yong-Min [Catholic University of Daegu, Gyeongsan (Korea, Republic of); Jung, Nam-Suk; Lee, Hee-Seock [POSTECH, Pohang (Korea, Republic of)

    2016-10-15

    Many foreign countries use separate criteria and regulation procedure according to the categorization of accelerators. In Korea, nuclear and radiation related facilities are divided into 4 groups: 1) Nuclear Reactor and related facilities, 2) Nuclear fuel cycle, nuclear material facilities, 3) Disposal and transport, 4) Radioisotope and radiation generating devices related facilities. All accelerator facilities are categorized as group 4 regardless of their size and type. For facilities that belong to group 1 and 2, Radiation Environmental Impact Assessment Report(REIR) and Preliminary Decommissioning Plan Report(PDPR) should be submitted in construction licensing stage, but there are no rules about above documents for large particle accelerator facilities. Facilities that belong to 4) RI and RG, only two documents of Radiation Safety Report(RSR) and Safety Control Regulation(SCR) are submitted in licensing stage. Because there is no detailed guidelines according to facilities type, properties of each facility are not considered in preparation and licensing process. If we set up the categorization of accelerator facilities, we can expect the effective and safe construction and operation of the large accelerator facilities on the licensing and operation process. Similarly to other counties' criteria, 50 MeV of particle energy could be used as energy band of large particle accelerator. According to categorization, it is necessary to adopt graded licensing stages and separated safety documents. In case of large particle accelerators, it is appropriate to divide the licensing stages to construction and operation. We currently submit PDPR in case of reactor and related facilities, nuclear fuel cycle, and nuclear material facilities. Depending on the energy of particle accelerators, it is necessary to prepare the decontamination and decommissioning for the decrease of current and future burden from radioactive waste. From the arrangement of separated guidelines on

  5. Heat generation by eddy currents in a shell of superconducting bus-bars for SIS100 particle accelerator at FAIR

    Directory of Open Access Journals (Sweden)

    Tomków Łukasz

    2017-12-01

    Full Text Available Superconducting magnets in the SIS100 particle accelerator require the supply of liquid helium and electric current. Both are transported with by-pass lines designed at Wrocław University of Technology. Bus-bars used to transfer an electric current between the sections of the accelerator will be encased in a steel shell. Eddy currents are expected to appear in the shell during fast-ramp operation of magnets. Heat generation, which should be limited in any cryogenic system, will appear in the shell. In this work the amount of heat generated is assessed depending on the geometry of an assembly of the bus-bars and the shell. Numerical and analytical calculations are described. It was found that heat generation in the shell is relatively small when compared to other sources present in the accelerator and its value strongly depends on the geometry of the shell. The distribution of eddy currents and generated heat for different geometrical options are presented. Based on the results of the calculations the optimal design is proposed.

  6. Selected topics in particle accelerators: Proceedings of the CAP meetings. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Parsa, Z. [ed.] [comp.

    1995-10-01

    This Report includes copies of transparencies and notes from the presentations made at the Center for Accelerator Physics at Brookhaven National Laboratory. Editing and changes to authors` contributions in this Report were made only to fulfill the publication requirements. This volume includes notes and transparencies on eight presentations: ``Inverse Cherenkov Laser Acceleration of Electron Beams``, ``High Brightness Field Emission Cathodes``, ``QCD/Teraflop Collaboration: The Future of Supercomputing``, ``Report on Dipole R&D``, ``Reaching Maximum Luminosity in Hadron Colliders at 10-100 TeV``, ``STAR Collaboration Project Status Report: Quarks and Gluons``, ``PHENIX Collaboration Project Status Report``, and ``Update on Status of BNL Relativistic Heavy Ion Collider (RHIC) Project: RHIC Design Issues.``

  7. Power System Design Compromises for Large-Scale Linear Particle Accelerators

    CERN Document Server

    Papastergiou, K D

    2014-01-01

    This paper discusses various design aspects of a 280MW Power System for the Compact Linear Collider (CLIC), a 50km long electrons-positrons accelerator, under feasibility evaluation. The key requirements are a very high accelerator availability and constant power flow from the utility grid, considering the pulsed power nature of CLIC. Firstly, the possible power network and cabling layouts are discussed along with potential difficulties on electrical fault clearance. Following, the use of active front-end converters is examined as a means to control the power flow and power quality seen by the 400kV grid. In particular a modular multilevel converter preliminary configuration is described and the compromises related to energy storage and voltage level are discussed.

  8. Relativity matters from Einstein's EMC2 to laser particle acceleration and quark-gluon plasma

    CERN Document Server

    Rafelski, Johann

    2017-01-01

    Rafelski presents Special Relativity in a language deemed accessible to students without any topical preparation - avoiding the burden of geometry, tensor calculus, and space-time symmetries – and yet advancing in highly contemporary context all the way to research frontiers. Special Relativity is presented such that nothing remains a paradox or just apparent, but rather is explained. A text of similar character, content, and scope, has not been available before. This book describes Special Relativity when rigid material bodies are introduced describing the reality of body contraction; it shows the relevance of acceleration and the necessary evolution of the theoretical framework when acceleration is critical. This book also presents the evolving views of Einstein about the aether. In addition to a careful and elementary introduction to relativity complete with exercises, worked examples and many discussions, this volume connects to current research topics so that readers can explore Special Relativity fr...

  9. Kinetic Alfven Waves Carrying Intense Field Aligned Currents: Particle Trapping and Electron Acceleration

    Science.gov (United States)

    Rankin, R.; Artemyev, A.

    2015-12-01

    It is now common knowledge that dispersive scale Alfvén waves can drive parallel electron acceleration [Lotko et al., JGR, 1998; Samson et al., Ann. Geophys., 2003; Wygant et al., JGR, 2002] and transverse ion energization in the auroral zone and inner magnetosphere [Johnson and Cheng, JGR, 2001; Chaston et al., 2004]. In this paper we show that relatively low energy electrons (plasma sheet electrons with energies ranging up to ˜100 eV) can be accelerated very efficiently as they interact nonlinearly with kinetic Alfvén waves (KAWs) that carry intense field aligned currents from the equatorial plane toward the ionosphere in the inner magnetosphere. We propose a theoretical model describing electron trapping into an effective wave potential generated by parallel wave electric fields (with perpendicular wavelengths on the order of the ion gyro-radius) and the mirror force acting on electrons as they propagate along geomagnetic field lines. We demonstrate that waves with an electric potential amplitude between ~100 - 400 V can trap and accelerate electrons to energies approaching several keVs. Trapping acceleration corresponds to conservation of the electron magnetic moment and, thus, results in a significant decrease of the electron equatorial pitch-angle with time. Analytical and numerical estimates of the maximum energy and probability of trapping are presented. We discuss the application of the proposed model in light of recent observations of electromagnetic fluctuations in the inner magnetosphere that are present during periods of strong geomagnetic activity [Chaston et al., GRL, 2014; Califf et al., JGR, 2015].

  10. Acceleration of Charged Particles by High Intensity Few-Cycle Laser Pulses

    CERN Document Server

    Schramm, Ulrich; Geissler, Michael; Grüner, Florian; Habs, Dietrich; Karsch, Stefan; Krausz, Ferenc; Meyer-ter-Vehn, J; Schmid, K; Schreiber, J; Tsakiris, George; Veisz, Laszlo; Witte, Klaus

    2005-01-01

    Only recently a breakthrough in laser plasma acceleration has been achieved with the observation of intense (nC) mono-energetic (10% relative width) electron beams in the 100MeV energy range.* Above the wave-breaking threshold the electrons are trapped and accelerated in a single wake of the laser pulse, called bubble, according to PIC simulations.** However, pulse energis varied from shot-to-shot in the experiments. At the MPQ Garching we prepare the stable acceleration of electrons by this bubble regime by the use of 10TW few-cycle laser pulse. As the pulse lenght of 5-10fs remains below the plasma period also at higher plama densities, we expect the scheme to be more stable and efficient. The status of the experiment will be reported. Further, we exploit a colliding beam setup existing at the Jena multi TW laser system for the investigation of the positron generation in the electron-electron collision or in the collision of hard X-rays resulting from Thomson backscattering. The presentation of results on h...

  11. Particle Rate and Host Accelerator Beam Loss on the MICE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Adam James [Imperial College, London (United Kingdom)

    2011-10-01

    A study is presented of particle rates in the MICE Muon Beamline and their relationship to beam loss produced in ISIS. A brief overview of neutrino physics is presented, together with a discussion on the Neutrino Factory as a motivation for MICE. An overview of MICE itself is then presented, highlighting the need for a systematic understanding of the relationship between the MICE target parameters, ISIS beam loss, and MICE particle rate. The variation of beam loss with target depth is examined and observed to be non-linear. The variation of beam loss with respect to the target dip time in the ISIS cycle is examined and observed to be approximately linear for dip times between 11.1 ms and 12.6 ms after ISIS injection, before tailing at earlier dip times. The variation of beam loss with particle rate is also observed to follow an approximately linear relationship from 0.05 V.ms to 4.7 V.ms beam loss, with a further strong indication that this continues up to 7.1 V.ms. Particle identification using time-of-flight data is used to give an insight into the relative abundances of each particle species present in the MICE beam. Estimates of muon rate are then produced as a function of beam loss. At a level of 2 V.ms beam loss ~10.9 muons per spill for a 3.2 ms spill with negative π → μ optics, and ~31.1 muons per 1 ms spill with positive π → μ optics are observed. Simulations using the ORBIT particle tracking code of the beam loss distributions around the ISIS ring, caused by the MICE target, are also presented and the implications for MICE running discussed.

  12. Coherent control in quantum open systems: An approach for accelerating dissipation-based quantum state generation

    Science.gov (United States)

    Chen, Ye-Hong; Shi, Zhi-Cheng; Song, Jie; Xia, Yan; Zheng, Shi-Biao

    2017-10-01

    In this paper, we propose an approach to accelerate the dissipation dynamics for quantum state generation with Lyapunov control. The strategy is to add target-state-related coherent control fields into the dissipation process to intuitively improve the evolution speed. By applying the current approach, without losing the advantages of dissipation dynamics, the target stationary states can be generated in a much shorter time as compared to that via traditional dissipation dynamics. As a result, the current approach containing the advantages of coherent unitary dynamics and dissipation dynamics allows for a significant improvement in quantum state generation.

  13. A Thin Lens Model for Charged-Particle RF Accelerating Gaps

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-07-01

    Presented is a thin-lens model for an RF accelerating gap that considers general axial fields without energy dependence or other a priori assumptions. Both the cosine and sine transit time factors (i.e., Fourier transforms) are required plus two additional functions; the Hilbert transforms the transit-time factors. The combination yields a complex-valued Hamiltonian rotating in the complex plane with synchronous phase. Using Hamiltonians the phase and energy gains are computed independently in the pre-gap and post-gap regions then aligned using the asymptotic values of wave number. Derivations of these results are outlined, examples are shown, and simulations with the model are presented.

  14. PARTICLE ACCELERATION AND MAGNETIC FIELD AMPLIFICATION IN THE JETS OF 4C74.26

    Energy Technology Data Exchange (ETDEWEB)

    Araudo, A. T.; Blundell, K. M. [University of Oxford, Astrophysics, Keble Road, Oxford OX1 3RH (United Kingdom); Bell, A. R. [University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom)

    2015-06-20

    We model the multi-wavelength emission in the southern hotspot of the radio quasar 4C74.26. The synchrotron radio emission is resolved near the shock with the MERLIN radio-interferometer, and the rapid decay of this emission behind the shock is interpreted as the decay of the amplified downstream magnetic field as expected for small scale turbulence. Electrons are accelerated to only 0.3 TeV, consistent with a diffusion coefficient many orders of magnitude greater than in the Bohm regime. If the same diffusion coefficient applies to the protons, their maximum energy is only ∼100 TeV.

  15. On the acceleration of high-energy particles in solar flares

    Science.gov (United States)

    Sakurai, K.

    1972-01-01

    The relationship is discussed between some characteristics of microwave Type 4 radio bursts and solar cosmic ray protons of MeV energy. It is shown that the peak flux intensity of those bursts is almost linearly correlated with MeV proton peak flux observed by satellites near the earth and that protons and electrons would be accelerated simultaneously by a similar mechanism during the explosive phase of solar flares. Brief discussion is given on the propagation of solar cosmic rays in the solar envelope after ejection from the flare regions.

  16. Constraining the equation of state with identified particle spectra

    Science.gov (United States)

    Monnai, Akihiko; Ollitrault, Jean-Yves

    2017-10-01

    We show that in a central nucleus-nucleus collision, the variation of the mean transverse mass with the multiplicity is determined, up to a rescaling, by the variation of the energy over entropy ratio as a function of the entropy density, thus providing a direct link between experimental data and the equation of state. Each colliding energy thus probes the equation of state at an effective entropy density, whose approximate value is 19 fm-3 for Au+Au collisions at 200 GeV and 41 fm-3 for Pb+Pb collisions at 2.76 TeV, corresponding to temperatures of 227 and 279 MeV if the equation of state is taken from lattice calculations. The relative change of the mean transverse mass as a function of the colliding energy gives a direct measure of the pressure over energy density ratio P /ɛ , at the corresponding effective density. Using Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) data, we obtain P /ɛ =0.21 ±0.10 , in agreement with the lattice value P /ɛ =0.23 in the corresponding temperature range. Measurements over a wide range of colliding energies using a single detector with good particle identification would help reduce the error.

  17. Acceleration of a ground-state reaction by selective femtosecond-infrared-laser-pulse excitation

    Science.gov (United States)

    Stensitzki, Till; Yang, Yang; Kozich, Valeri; Ahmed, Ashour A.; Kössl, Florian; Kühn, Oliver; Heyne, Karsten

    2018-02-01

    Infrared (IR) excitation of vibrations that participate in the reaction coordinate of an otherwise thermally driven chemical reaction are believed to lead to its acceleration. Attempts at the practical realization of this concept have been hampered so far by competing processes leading to sample heating. Here we demonstrate, using femtosecond IR-pump IR-probe experiments, the acceleration of urethane and polyurethane formation due to vibrational excitation of the reactants for 1:1 mixtures of phenylisocyanate and cyclohexanol, and toluene-2,4-diisocyanate and 2,2,2-trichloroethane-1,1-diol, respectively. We measured reaction rate changes upon selective vibrational excitation with negligible heating of the sample and observed an increase of the reaction rate up to 24%. The observation is rationalized using reactant and transition-state structures obtained from quantum chemical calculations. We subsequently used IR-driven reaction acceleration to write a polyurethane square on sample windows using a femtosecond IR pulse.

  18. Contemporaneous multi-wavelength observations of the gamma-ray emitting active galaxy IC 310. New clues on particle acceleration in extragalactic jets

    Energy Technology Data Exchange (ETDEWEB)

    Glawion, Dorit

    2015-05-08

    -law function over two orders of magnitude in energy up to ∝10 TeV. Compared to previous observations, no significant variability of the spectral shape was found. Together with the constraint on the viewing angle, this challenges the currently accepted models for particle acceleration at shock waves in the jets. Alternative models, such as stars moving through the jets, mini-jets in the jet caused, e.g., by reconnection events, or gap acceleration in a pulsar-like magnetosphere around the black hole were investigated. It was found that only the latter can explain all observational findings, which at least suggests that it could even be worthwhile to reconsider published investigations of AGN with this new knowledge in mind. The first multi-wavelength campaign was successfully been conducted in 2012/2013, including ground-based as well as space-based telescopes in the radio, optical, ultraviolet, X-ray, and gamma-ray energy range. No pronounced variability was found after the TeV flare in any energy band. The X-ray data showed a slightly harder spectrum when the emission was brighter. The long-term radio light curve indicated a flickering flux variability, but no strong hint for a new jet component was found from VLBI images of the radio jet. In any case, further analysis of the existing multi-wavelength data as well as complimentary measurements could provide further exciting insights, e.g., about the broad band spectral energy distribution. Overall, it can be stated that IC 310 is a key object for research of active galactic nuclei in the high-energy band due to its proximity and its peculiar properties regarding flux variability and spectral behavior. Such objects are ideally suited for studying particle acceleration, jet formation, and other physical effects and models which are far from being fully understood.

  19. The steady state of a particle in a vibrating box and possible ...

    Indian Academy of Sciences (India)

    In particular, the parameter range is found in which the particle oscillates between the walls in steady state as if the wall was static and it is showed that for these parameter ranges the particle settles to this steady state for all initial conditions. It is proposed that this phenomenon can be used to bunch charged particles in ...

  20. Modeling Lost-Particle Accelerator Backgrounds in PEP-II Using LPTURTLE

    CERN Document Server

    Fieguth, Theodore; Kozanecki, Witold

    2005-01-01

    Background studies during the design, construction, commissioning, operation and improvement of BaBar and PEP-II have been greatly influenced by results from a program referred to as LPTURTLE (Lost Particle TURTLE a modified version of Decay TURTLE) which was originally conceived for the purpose of studying gas background for SLC. This venerable program is still in use today. We describe its use, capabilities and improvements and refer to current results now being applied to BaBar.

  1. GPUs, a new tool of acceleration in CFD: efficiency and reliability on smoothed particle hydrodynamics methods.

    Directory of Open Access Journals (Sweden)

    Alejandro C Crespo

    Full Text Available Smoothed Particle Hydrodynamics (SPH is a numerical method commonly used in Computational Fluid Dynamics (CFD to simulate complex free-surface flows. Simulations with this mesh-free particle method far exceed the capacity of a single processor. In this paper, as part of a dual-functioning code for either central processing units (CPUs or Graphics Processor Units (GPUs, a parallelisation using GPUs is presented. The GPU parallelisation technique uses the Compute Unified Device Architecture (CUDA of nVidia devices. Simulations with more than one million particles on a single GPU card exhibit speedups of up to two orders of magnitude over using a single-core CPU. It is demonstrated that the code achieves different speedups with different CUDA-enabled GPUs. The numerical behaviour of the SPH code is validated with a standard benchmark test case of dam break flow impacting on an obstacle where good agreement with the experimental results is observed. Both the achieved speed-ups and the quantitative agreement with experiments suggest that CUDA-based GPU programming can be used in SPH methods with efficiency and reliability.

  2. HTS Dipole Magnet for a Particle Accelerator using a Twisted Stacked Cable

    CERN Document Server

    Himbele, John J.; Tixador, Pascal

    2016-01-01

    changes during the quench. Due to the large temperature margin between the operation and the current sharing temperatures, the normal zone does not propagate with the temperature front. This means that the temperature will rise in a considerably larger volume when compared to the quenched volume. Thus, the evolution of the temperature distribution below current sharing temperature Tcs after the quench onset affects the normal zone propagation velocity in HTS more than in LTS coils. This can be seen as an acceleration of the quench propagation velocities while the quench evolves when margin to Tcs is high. In this paper we scrutinize quench propagation in a stack of YBCO cables with an in-house finite element method software which solves the heat diffusion equation. We compute the longitudinal and transverse normal zone propagation velocities at various distances from the hot spot to demonstrate the distance-variation...

  3. Muon Sources for Particle Physics - Accomplishments of the Muon Accelerator Program

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Stratakis, D. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Palmer, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Delahaye, J.-P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Summers, D. [Univ. of Mississippi, Oxford, MS (United States); Ryne, R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cummings, M. A. [Muons, Inc., Batavia, IL(United States)

    2017-05-01

    The Muon Accelerator Program (MAP) completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a μ storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of νe (ν$\\bar{e}$) and ν$\\bar{μ}$) (νμ) beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components were obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent

  4. Sir John Adams: his legacy to the world of particle accelerators

    CERN Document Server

    Wilson, E J N

    2011-01-01

    John Adams acquired an unrivalled reputation for his leading part in designing and constructing the Proton Synchrotron (PS) in CERN’s early days. In 1968, and after several years heading a fusion laboratory in the UK, he came back to Geneva to pilot the Super Proton Synchrotron (SPS) project to approval and then to direct its construction. By the time of his early death in 1984 he had built the two flagship proton accelerators at CERN and, during the second of his terms as Director-General, he laid the groundwork for the proton–antiproton collider which led to the discovery of the intermediate vector boson. How did someone without any formal academic qualification achieve this? What was the magic behind his leadership? The speaker, who worked many years alongside him, will discuss these questions and speculate on how Sir John Adams might have viewed today’s CERN.

  5. Study of Nb-Cu 1.3 GHz SRF cavity resonators for future particle accelerators

    CERN Document Server

    Amelin, Kirill

    2017-01-01

    Niobium-coated superconducting radio-frequency cavities have a number of advantages over cavities made from bulk niobium. Cavities coated with high-power impulse magnetron sputtering are tested at CERN in order to optimize the coating and study the Q-slope that limits the performance. To accurately measure the quality factor as a function of accelerating field, it is important to have good matching between an input antenna and a cavity impedance. To improve the matching, a variable coupler that changes the length of the antenna can be used. We have shown that the Q-factor of the input antenna can be changed between $10^7-10^{11}$ by moving the antenna, which should allow to achieve critical coupling with a cavity. This technology could be used in future measurements, so that reflections are always minimized.

  6. Lasers As Particle Accelerators In Medicine: From Laser-Driven Protons To Imaging With Thomson Sources

    Science.gov (United States)

    Pogorelsky, I. V.; Babzien, M.; Polyanskiy, M. N.; Yakimenko, V.; Dover, N. P.; Palmer, C. A. J.; Najmudin, Z.; Shkolnikov, P.; Williams, O.; Rosenzweig, J.; Oliva, P.; Carpinelli, M.; Golosio, B.; Delogu, P.; Stefanini, A.; Endrizzi, M.

    2011-06-01

    We report our recent progress using a high-power, picosecond CO2 laser for Thomson scattering and ion acceleration experiments. These experiments capitalize on certain advantages of long-wavelength CO2 lasers, such as their high number of photons per energy unit and beneficial wavelength- scaling of the electrons' ponderomotive energy and critical plasma frequency. High X-ray fluxes produced in the interactions of the counter-propagating laser- and electron-beams for obtaining single-shot, high-contrast images of biological objects. The laser, focused on a hydrogen jet, generated a monoenergetic proton beam via the radiation-pressure mechanism. The energy of protons produced by this method scales linearly with the laser's intensity. We present a plan for scaling the process into the range of 100-MeV proton energy via upgrading the CO2 laser. This development will enable an advance to the laser-driven proton cancer therapy.

  7. The Real-Time Data Analysis and Decision System for Particle Flux Detection in the LHC Accelerator at CERN.

    CERN Document Server

    Zamantzas, C; Dehning, B

    2006-01-01

    The superconducting Large Hadron Collider (LHC) under construction at the European Organisation for Nuclear Research (CERN) is an accelerator unprecedented in terms of beam energy, particle production rate and also in the potential of self-destruction. Its operation requires a large variety of instrumentation, not only for the control of the beams, but also for the protection of the complex hardware systems. The Beam Loss Monitoring (BLM) system has to prevent the superconducting magnets from becoming normal conducting and protect the machine components against damages making it one of the most critical elements for the protection of the LHC. For its operation, the system requires 3600 detectors to be placed at various locations around the 27 km ring. The measurement system is sub-divided to the tunnel electronics, which are responsible for acquiring, digitising and transmitting the data, and the surface electronics, which receive the data via 2 km optical data links, process, analyze, store and issue warning...

  8. Laser-driven particle acceleration for radiobiology and radiotherapy: where we are and where we are going

    Science.gov (United States)

    Giulietti, Antonio

    2017-05-01

    Radiation therapy of tumors progresses continuously and so do devices, sharing a global market of about $ 4 billions, growing at an annual rate exceeding 5%. Most of the progress involves tumor targeting, multi-beam irradiation, reduction of damage on healthy tissues and critical organs, dose fractioning. This fast-evolving scenario is the moving benchmark for the progress of the laser-based accelerators towards clinical uses. As for electrons, both energy and dose requested by radiotherapy are available with plasma accelerators driven by lasers in the power range of tens of TW but several issues have still to be faced before getting a prototype device for clinical tests. They include capability of varying electron energy, stability of the process, reliability for medical users. On the other side hadron therapy, presently applied to a small fraction of cases but within an exponential growth, is a primary option for the future. With such a strong motivation, research on laser-based proton/ion acceleration has been supported in the last decade in order to get performances suitable to clinical standards. None of these performances has been achieved so far with laser techniques. In the meantime a rich crop of data have been obtained in radiobiological experiments performed with beams of particles produced with laser techniques. It is quite significant however that most of the experiments have been performed moving bio samples to laser labs, rather moving laser equipment to bio labs or clinical contexts. This give us the measure that laser community cannot so far provide practical devices usable by non-laser people.

  9. Electron acceleration through wave-particle interactions in the Van Allen belts: results of the MAARBLE project

    Science.gov (United States)

    Daglis, Ioannis A.; Turner, Drew; Balasis, Georgios; Papadimitriou, Constantinos; Georgiou, Marina; Katsavrias, Christos

    Wave-particle interactions in the inner magnetosphere play a critical role in the acceleration of electrons to high energies characteristic of the Van Allen belts. In the MAARBLE project we have been investigating the properties of ultra-low-frequency electromagnetic waves in the magnetosphere and the particular ways in which these waves can influence electron acceleration. For a number of selected intense magnetic storms, we studied the variations of energetic electron fluxes in the outer Van Allen belt along with variations of the power of Pc 4-5 waves and their earthward penetration, using multi-point observations both from a number of spacecraft and from ground-based magnetometer arrays. We present and discuss the results of this study. The work leading to this paper has received funding from the European Union’s Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520 for the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project. This paper reflects only the authors’ views and the Union is not liable for any use that may be made of the information contained therein.

  10. Metal speciation dynamics in dispersions of soft colloidal ligand particles under steady-state laminar flow condition.

    Science.gov (United States)

    Duval, Jérôme F L; Qian, Shizhi

    2009-11-19

    A theory is presented for metal speciation dynamics in a swarm of soft, spherical core-hell colloidal ligand particles under steady-state laminar flow condition. Mass transfer and subsequent complexation of metal species within the reactive, permeable particle shell are governed by the interplay between (i) convective-diffusion of free metal ions M within and around the shell where ligands L are distributed, and (ii) kinetics of ML complex formation/dissociation in the shell. The local concentrations of metal M and complex ML are determined by the convective-diffusion equations with appropriate chemical source term and full account of radial and angular concentration polarization contributions. The steady-state flow field is determined from the solution of Navier-tokes equation including convective acceleration term for the fluid external to the particle, and from Brinkman equation for the internal fluid flow. The confined location of ligands within the particle shell leads to ML formation/dissociation rate constants (denoted as ka* and kd*, respectively) that differ significantly from their counterparts (ka and kd) defined for homogeneous ligand distribution throughout the solution. The relationship between ka,d* and ka,d is derived from the numerical evaluation of the spatial, time-dependent distributions of free and bound metal within and/or outside the particle. The dramatic dependence of ka,d* on hydrodynamic particle softness, Péclet number, soft surface layer thickness, and particle radius are analyzed in the steady-state nonequilibrium chemical regime within the context of dynamic features for colloidal complexes. The analysis covers the limiting cases of hydrodynamically impermeable, hard particles where binding sites are located at the very surface of the particle core (e.g., functionalized latex colloids) and free draining, polymeric ligand particles devoid of a hard core (e.g., porous gel particles). The formalism further applies to any values of the

  11. In view of accelerating CFD simulations through coupling with vortex particle approximations

    Science.gov (United States)

    Papadakis, Giorgos; Voutsinas, Spyros G.

    2014-06-01

    In order to exploit the capabilities of Computational Fluid Dynamics in aerodynamic design, the cost should be reduced without compromising accuracy and consistency. In this direction a hybrid methodology is formulated within the context of domain decomposition. The strategy is to choose in each sub-domain the best performing method. Close to solid boundaries a grid-based Eulerian flow solver is used while in the far field the flow is described in Lagrangian coordinates using particle approximations. Aiming at consistently including compressible effects, particles carry mass, dilatation, vorticity and energy and the complete set of conservation laws is solved in Lagrangian coordinates. At software level, the URANS solver MaPFlow is coupled to the vortex code GENUVP. In the present paper the two dimensional formulation is given alongside with validation tests around airfoils in steady and inherently unsteady conditions. It is verified that: purely Eulerian and hybrid simulations are equivalent; the Eulerian domain in the hybrid solver can be effectively restricted to a layer 1.5 chord lengths wide; significant cost reduction reaching up to 1:3 ratio is achieved.

  12. Comparison of the Effects of Wave-Particle Interactions and the Kinetic Suprathermal Electron Population on the Acceleration of the Solar Wind

    Science.gov (United States)

    Tam, S. W. Y.; Chang, T.

    2002-01-01

    Kinetic effects due to wave-particle interactions and suprathermal electrons have been suggested in the literature as possible solar wind acceleration mechanisms. Ion cyclotron resonant heating, in particular, has been associated with some qualitative features observed in the solar wind. In terms of solar wind acceleration, however, it is interesting to compare the kinetic effects of suprathermal electrons with those due to the wave-particle interactions. The combined effects of the two acceleration mechanisms on the fast solar wind have been studied by Tam and Chang (1999a,b). In this study. we investigate the role of the suprathermal electron population in the acceleration of the solar wind. Our model follows the global kinetic evolution of the fast solar wind under the influence of ion cyclotron resonant heating, while taking into account Coulomb collisions, and the ambipolar electric field that is consistent with the particle distributions themselves. The kinetic effects due to the suprathermal electrons, which we define to be the tail of the electron distributions, can be included in the model as an option. By comparing the results with and without the inclusion of the suprathermal electron effects, we determine the relative importance of suprathermal electrons and wave-particle interactions in driving the solar wind. We find that although suprathermal electrons enhance the ambipolar electric potential in the solar wind considerably, their overall influence as an acceleration mechanism is relatively insignificant in a wave-driven solar wind.

  13. Beam-Induced Multipactoring and Electron-Cloud Effects in Particle Accelerators

    CERN Document Server

    Caspers, Friedhelm; Scandale, Walter; Zimmermann, F

    2009-01-01

    In the beam pipe of high-energy proton or positron accelerators an “electron cloud” can be generated by a variety of processes, e.g. by residual-gas ionization, by photoemission from synchrotron radiation, and, most importantly, by secondary emission via a beam-induced multipactoring process. The electron cloud commonly leads to a degradation of the beam vacuum by several orders of magnitude, to fast beam instabilities, to beam-size increases, and to fast or slow beam losses. At the Large Hadron Collider (LHC), the cloud electrons could also give rise to an additional heat load inside cold superconducting magnets. In addition to the direct heat deposition from incoherently moving electrons, a potential “magnetron effect” has been conjectured, where electrons would radiate coherently when moving in a strong magnetic field under the simultaneous influence of a beam-induced electric “wake” field that may become resonant with the cyclotron frequency. Electron-cloud effects are already being observed w...

  14. Low Secondary Electron Yield Carbon Coatings for Electron Cloud Mitigation in Modern Particle Accelerators

    CERN Document Server

    Yin Vallgren, Christina; Taborelli, Mauro

    2011-01-01

    In order to upgrade the Large Hadron Collider (LHC) performance to be oriented towards higher energies and higher intensities in the future, a series of improvements of the existing LHC injectors is planned to take place over the next few years. Electron cloud effects are expected to be enhanced and play a central role in limiting the performance of the machines of the CERN complex. Electron cloud phenomena in beam pipes are based on electron multiplication and can be sufficiently suppressed if the Secondary Electron Yield (SEY) of the surface of the beam pipes is lower than unity. The goal of this work is to find and study a thin film coating with reliably low initial Secondary Electron Yield (SEY), which does not require bake-out or conditioning in situ with photons, is robust again air exposure and can easily be applied in the beam pipes of accelerators. In this work, amorphous carbon (a-C) thin films have been prepared by DC magnetron sputtering for electron cloud mitigation and antimultipactor applicatio...

  15. Accelerated Detection of Viral Particles by Combining AC Electric Field Effects and Micro-Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Matthew Robert Tomkins

    2015-01-01

    Full Text Available A detection method that combines electric field-assisted virus capture on antibody-decorated surfaces with the “fingerprinting” capabilities of micro-Raman spectroscopy is demonstrated for the case of M13 virus in water. The proof-of-principle surface mapping of model bioparticles (protein coated polystyrene spheres captured by an AC electric field between planar microelectrodes is presented with a methodology for analyzing the resulting spectra by comparing relative peak intensities. The same principle is applied to dielectrophoretically captured M13 phage particles whose presence is indirectly confirmed with micro-Raman spectroscopy using NeutrAvidin-Cy3 as a labeling molecule. It is concluded that the combination of electrokinetically driven virus sampling and micro-Raman based signal transduction provides a promising approach for time-efficient and in situ detection of viruses.

  16. Interactive visual intervention planning in particle accelerator environments with ionizing radiation

    CERN Document Server

    Fabry, Thomas

    Radiation is omnipresent. It has many interesting applications: in medicine, where it allows curing and diagnosing patients; in communication, where modern communication systems make use of electromagnetic radiation; and in science, where it is used to discover the structure of materials; to name a few. Physically, radiation is a process in which particles or waves travel through any kind of material, usually air. Radiation can be very energetic, in which case it can break the atoms of ordinary matter (ionization). If this is the case, radiation is called ionizing. It is known that ionizing radiation can be far more harmful to living beings than non-ionizing radiation. In this dissertation, we are concerned with ionizing radiation. Naturally occurring ionizing radiation in the form of radioactivity is a most natural phenomenon. Almost everything is radioactive: there is radiation emerging from the soil, it is in the air, and the whole planet is constantly undergoing streams of energetic cosmic radiation. Sinc...

  17. Vacuum Simulations in High Energy Accelerators and Distribution Properties of Continuous and Discrete Particle Motions

    CERN Document Server

    Aichinger, Ida; Kersevan, Roberto

    The underlying thesis on mathematical simulation methods in application and theory is structured into three parts. The first part sets up a mathematical model capable of predicting the performance and operation of an accelerator’s vacuum system based on analytical methods. A coupled species-balance equation system describes the distribution of the gas dynamics in an ultra-high vacuum system considering impacts of conductance limitations, beam induced effects (ion-, electron-, and photon-induced de- sorption), thermal outgassing and sticking probabilities of the chamber materials. A new solving algorithm based on sparse matrix representations, is introduced and presents a closed form solution of the equation system. The model is implemented in a Python environment, named PyVasco, and is supported by a graphical user interface to make it easy available for everyone. A sensitivity analysis, a cross-check with the Test-Particle Monte Carlo simulation program Molflow+ and a comparison of the simulation results t...

  18. Spatio-temporal radiation biology with conventionally or laser-accelerated particles for ELIMED

    Energy Technology Data Exchange (ETDEWEB)

    Ristić-Fira, A.; Bulat, T.; Keta, O.; Petrović, I. [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Romano, F.; Cirrone, P.; Cuttone, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, Catania (Italy)

    2013-07-26

    The aim of this study is to investigate the behavior of radio-resistant human malignant cells, thus enabling better understanding of radiobiological effects of ions in such a case. Radiation sources such as accelerated continuous ion beams and laser technology-based ultra short radiation sources with energy of around 10 MeV will be used. The HTB140 melanoma cells are chosen since it has been shown that they represent the limit case of cellular radio-resistance among the studied tumor cell lines. These cells are particularly interesting as they provide data on the very edge of inactivation capacity of each beam line that is tested. After exposing the cell monolayers to continuous radiations of low (γ-rays) and high (protons) linear energy transfer, the kinetics of disappearance of the phosphorylated histone H2AX (γ-H2AX) foci per cell will be determined. The same procedure will be performed with the pulsed high dose rate protons. Detection and quantification of γ-H2AX foci will be performed by immunohistochemical 3D time-dependent imaging analyses using laser scanning confocal microscopy. Immunoblotting will enable the follow-up of the relation between γ-H2AX and cell cycle arrest via the p53/p21 pathway. In such a way the spatio-temporal changes on sub-cellular level will be visualized, quantified and compared. These results will show whether there is a difference in the effects on cells between continuous and pulsed irradiation mode. Therefore, they will contribute to the data base that might promote pulsed sources for medical treatments of malignant growths.

  19. A Steady-state Spectral Model for Electron Acceleration and Cooling in Blazar Jets: Application to 3C 279

    Science.gov (United States)

    Lewis, Tiffany R.; Finke, Justin D.; Becker, Peter A.

    2018-01-01

    We introduce a new theoretical model to describe the emitting region in a blazar jet. We adopt a one-zone leptonic picture and construct the particle transport equation for a plasma blob experiencing low-energy, monoenergetic particle injection, energy-dependent particle escape, shock acceleration, adiabatic expansion, stochastic acceleration, synchrotron radiation, and external Compton radiation from the dust torus and broad-line region (BLR). We demonstrate that a one-zone leptonic model is able to explain the IR though γ -ray spectrum for 3C 279 in 2008–2009. We determine that the BLR seed photons cannot be adequately described by a single average distribution, but rather we find that a stratified BLR provides an improvement in the estimation of the distance of the emitting region from the black hole. We calculate that the jet is not always in equipartition between the particles and magnetic field and find that stochastic acceleration provides more energy to the particles than does shock acceleration, where the latter is also overshadowed by adiabatic losses. We further introduce a novel technique to implement numerical boundary conditions and determine the global normalization for the electron distribution, based on analysis of stiff ordinary differential equations. Our astrophysical results are compared with those obtained by previous authors.

  20. The infancy of particle accelerators life and work of Rolf Wideröe

    CERN Document Server

    1994-01-01

    by Pedro Waloschek The following autobiographical account of Rolf Wideröe's life and work is based on manuscripts and letters written by hirnself, most ofthem especially for this report. Data from audio and video recordings with his illustrations and from my notes taken during aseries ofmeetings between the two ofus were also included. Rolf Wideröe gave me access to many of his publications and to other documents from which I have extracted further information. I have compiled, edited and, where necessary, put the texts in chronological order. These were then corrected and supplemented by Rolf Wideröe during the course of several readings. The English translation was also checked by Wideröe and we were able to add some improvements and corrections. This account there­ fore stands as an authorised biography and is written in the first person. Mrs. Wideröe's accurate memory was of great assistance. The emphasis has been on RolfWideröe's life story and the first developments which led to modem particle ac...

  1. Statistical analysis for the radiological characterization of radioactive waste in particle accelerators

    CERN Document Server

    AUTHOR|(CDS)2085595; Luccioni, Catherine

    This thesis introduces a new method to characterize metallic very-low-level radioactive waste produced at the European Organization for Nuclear Research (CERN). The method is based on: 1. the calculation of a preliminary radionuclide inventory, which is the list of the radionuclides that can be produced when particles interact with a surrounding medium, 2. the direct measurement of γ emitters and, 3. the quantification of pure-α, pure-β and low-energy X-ray emitters, called difficult-to-measure (DTM) radionuclides, using the so-called scaling factor (SF), correlation factor (CF) and mean activity (MA) techniques. The first stage of the characterization process is the calculation of the radionuclide inventory via either analytical or Monte Carlo codes. Once the preliminary radionuclide inventory is obtained, the γ-emitting radionuclides are measured via γ-ray spectrometry on each package of the waste population. The major γ-emitter, called key nuclide (KN), is also identified. The scaling factor method e...

  2. Smooth Particle Hydrodynamics GPU-Acceleration Tool for Asteroid Fragmentation Simulation

    Science.gov (United States)

    Buruchenko, Sergey K.; Schäfer, Christoph M.; Maindl, Thomas I.

    2017-10-01

    The impact threat of near-Earth objects (NEOs) is a concern to the global community, as evidenced by the Chelyabinsk event (caused by a 17-m meteorite) in Russia on February 15, 2013 and a near miss by asteroid 2012 DA14 ( 30 m diameter), on the same day. The expected energy, from either a low-altitude air burst or direct impact, would have severe consequences, especially in populated regions. To mitigate this threat one of the methods is employment of large kinetic-energy impactors (KEIs). The simulation of asteroid target fragmentation is a challenging task which demands efficient and accurate numerical methods with large computational power. Modern graphics processing units (GPUs) lead to a major increase 10 times and more in the performance of the computation of astrophysical and high velocity impacts. The paper presents a new implementation of the numerical method smooth particle hydrodynamics (SPH) using NVIDIA-GPU and the first astrophysical and high velocity application of the new code. The code allows for a tremendous increase in speed of astrophysical simulations with SPH and self-gravity at low costs for new hardware. We have implemented the SPH equations to model gas, liquids and elastic, and plastic solid bodies and added a fragmentation model for brittle materials. Self-gravity may be optionally included in the simulations.

  3. Reliability and Lifetime Prediction of Remote Phosphor Plates in Solid-State Lighting Applications Using Accelerated Degradation Testing

    NARCIS (Netherlands)

    Yazdan Mehr, M.; van Driel, W.D.; Zhang, G.Q.

    2015-01-01

    A methodology, based on accelerated degradation testing, is developed to predict the lifetime of remote phosphor plates used in solid-state lighting (SSL) applications. Both thermal stress and light intensity are used to accelerate degradation reaction in remote phosphor plates. A reliability model,

  4. A chain-of-states acceleration method for the efficient location of minimum energy paths

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, E. R., E-mail: Eduardo.Hernandez@csic.es; Herrero, C. P. [Instituto de Ciencia de Materiales de Madrid (ICMM–CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Soler, J. M. [Departamento de Física de la Materia Condensada and IFIMAC, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2015-11-14

    We describe a robust and efficient chain-of-states method for computing Minimum Energy Paths (MEPs) associated to barrier-crossing events in poly-atomic systems, which we call the acceleration method. The path is parametrized in terms of a continuous variable t ∈ [0, 1] that plays the role of time. In contrast to previous chain-of-states algorithms such as the nudged elastic band or string methods, where the positions of the states in the chain are taken as variational parameters in the search for the MEP, our strategy is to formulate the problem in terms of the second derivatives of the coordinates with respect to t, i.e., the state accelerations. We show this to result in a very simple and efficient method for determining the MEP. We describe the application of the method to a series of test cases, including two low-dimensional problems and the Stone-Wales transformation in C{sub 60}.

  5. High-Repeatable Data Acquisition Systems for Pulsed Power Converters in Particle Accelerator Structures

    CERN Document Server

    AUTHOR|(CDS)2087245; Martino, Michele; Zinno, Raffaele

    In this Ph.D. thesis, the issues related to the metrological characterization of high-performance pulsed power converters are addressed. Initially, a background and a state of the art on the measurement systems needed to correctly operate a high-performance power converter are presented. As a matter of fact, power converters usually exploits digital control loops to enhance their performance. In this context the final performance of a power converter has to be validated by a reference instrument with higher metrological characteristics. In addition, an on-line measurement systemis also needed to digitize the quantity to be controlled with high accuracy. Then, in industrial applications of power converters metrology, specifications are given in terms of Worst-Case Uncertainty (WCU). Therefore, an analytical model for predicting the Worst-Case Uncertainty (WCU) of a measurement system is discussed and detailed for an instrument affected by Gaussian noise. Furthermore, the study and the design of a Reference Acq...

  6. Natural air convection for cooling of particle accelerator electromagnets: case studies at CERN

    CERN Document Server

    Moreira, Mariana

    Cooling by natural convection is investigated on two air-cooled corrector magnets at CERN. The heat transfer coefficient (HTC) for each magnet is estimated analytically using established empirical correlations for certain geometries. The HTC is also estimated numerically with three-dimensional steady-state finite element simulations. Air convection around the respective coils as well as heat conduction inside the coils are modelled. Different formulas for the HTC are tested in the post-processing of the simulation results. The HTC for each magnet is then determined experimentally by measuring surface temperatures on the coils through time at constant currents. A method to extract the HTC from these temperature curves is developed, in which the curves are fitted to a function that is derived from a thermodynamical analysis of the heating process. Some plausible ranges for the HTC for each magnet for different currents are obtained. The results of the different estimation methods are compared with the experimen...

  7. Acceleration effects on atomic clocks

    CERN Document Server

    Dahia, F

    2014-01-01

    We consider a free massive particle inside a box which is dragged by Rindler observers. Admitting that the particle obeys the Klein-Gordon equation, we find the frequencies of the stationary states of this system. Transitions between the stationary states are employed to set a standard frequency for a toy atomic clock. Comparing the energy spectrum of the accelerated system with the energy spectrum of an identical system in an inertial frame, we determine the influence of the instantaneous acceleration on the rate of atomic clocks. We argue that our result does not violate the clock hypothesis.

  8. Quantitative determination of carbonaceous particle mixing state in Paris using single-particle mass spectrometer and aerosol mass spectrometer measurements

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2013-09-01

    Full Text Available Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC, organic aerosol (OA, ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, a thermal–optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC. ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R2 = 0.67–0.78, and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA is associated with two mixing states which differ significantly in their OA / EC ratios. Aged biomass burning OA (OOA2-BBOA was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the

  9. Machine Protection and High Energy Density States in Matter for High Energy Hadron Accelerators

    CERN Document Server

    Blanco Sancho, Juan; Schmidt, R

    The Large Hadron Collider (LHC) is the largest accelerator in the world. It is designed to collide two proton beams with unprecedented particle energy of 7TeV. The energy stored in each beam is 362MJ, sufficient to melt 500kg of copper. An accidental release of even a small fraction of the beam energy can result in severe damage to the equipment. Machine protection systems are essential to safely operate the accelerator and handle all possible accidents. This thesis deals with the study of different failure scenarios and its possible consequences. It addresses failure scenarios ranging from low intensity losses on high-Z materials and superconductors to high intensity losses on carbon and copper collimators. Low beam losses are sufficient to quench the superconducting magnets and the stabilized superconducting cables (bus-bars) that connects the main magnets. If this occurs and the energy from the bus-bar is not extracted fast enough it can lead to a situation similar to the accident in 2008 at LHC during pow...

  10. Self-consistent Monte Carlo simulations of proton acceleration in coronal shocks: Effect of anisotropic pitch-angle scattering of particles

    CERN Document Server

    Afanasiev, Alexandr; Vainio, Rami

    2016-01-01

    Context. Solar energetic particles observed in association with coronal mass ejections (CMEs) are produced by the CME-driven shock waves. The acceleration of particles is considered to be due to diffusive shock acceleration (DSA). Aims. We aim at a better understanding of DSA in the case of quasi-parallel shocks, in which self-generated turbulence in the shock vicinity plays a key role. Methods. We have developed and applied a new Monte Carlo simulation code for acceleration of protons in parallel coronal shocks. The code performs a self-consistent calculation of resonant interactions of particles with Alfv\\'en waves based on the quasi-linear theory. In contrast to the existing Monte Carlo codes of DSA, the new code features the full quasi-linear resonance condition of particle pitch-angle scattering. This allows us to take anisotropy of particle pitch-angle scattering into account, while the older codes implement an approximate resonance condition leading to isotropic scattering.We performed simulations with...

  11. Steady-state particle tracking in the object-oriented regional groundwater model ZOOMQ3D

    OpenAIRE

    Jackson, C.R.

    2002-01-01

    This report describes the development of a steady-state particle tracking code for use in conjunction with the object-oriented regional groundwater flow model, ZOOMQ3D (Jackson, 2001). Like the flow model, the particle tracking software, ZOOPT, is written using an object-oriented approach to promote its extensibility and flexibility. ZOOPT enables the definition of steady-state pathlines in three dimensions. Particles can be tracked in both the forward and reverse directions en...

  12. Particle acceleration model for the broad-band baseline spectrum of the Crab nebula

    Science.gov (United States)

    Fraschetti, F.; Pohl, M.

    2017-11-01

    We develop a simple one-zone model of the steady-state Crab nebula spectrum encompassing both the radio/soft X-ray and the GeV/multi-TeV observations. By solving the transport equation for GeV-TeV electrons injected at the wind termination shock as a log-parabola momentum distribution and evolved via energy losses, we determine analytically the resulting differential energy spectrum of photons. We find an impressive agreement with the observed spectrum of synchrotron emission, and the synchrotron self-Compton component reproduces the previously unexplained broad 200-GeV peak that matches the Fermi/Large Area Telescope (LAT) data beyond 1 GeV with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) data. We determine the parameters of the single log-parabola electron injection distribution, in contrast with multiple broken power-law electron spectra proposed in the literature. The resulting photon differential spectrum provides a natural interpretation of the deviation from power law customarily fitted with empirical multiple broken power laws. Our model can be applied to the radio-to-multi-TeV spectrum of a variety of astrophysical outflows, including pulsar wind nebulae and supernova remnants, as well as to interplanetary shocks.

  13. Accelerated bridge construction utilizing precast pier caps on state highway 69 over Turkey Creek, Huerfano County, CO.

    Science.gov (United States)

    2014-07-01

    The purpose of this report is to document Accelerated Bridge Construction (ABC) techniques on IBRD : (Innovative Bridge Research and Development) project 102470 for the construction of Bridge N-16-Q : on State Highway 69 over Turkey Creek. The constr...

  14. Why hadronic resonances and particle unstable states are interesting?

    Directory of Open Access Journals (Sweden)

    Aichelin J.

    2015-01-01

    Full Text Available We discuss the (few achievements and the (many open questions of the theoretical interpretation of the recent data on unstable particles in pp, pA and AA collisions at ultrarelativistic energies.

  15. Quantum field theory and the internal states of elementary particles

    CSIR Research Space (South Africa)

    Greben, JM

    2011-01-01

    Full Text Available A new application of quantum field theory is developed that gives a description of the internal dynamics of dressed elementary particles and predicts their masses. The fermionic and bosonic quantum fields are treated as interdependent fields...

  16. Analysis of the dependence of surfatron acceleration of electrons by an electromagnetic wave in space plasma on the particle momentum along the wave front

    Energy Technology Data Exchange (ETDEWEB)

    Erokhin, A. N., E-mail: nerokhin@mx.iki.rssi.ru [People’s Friendship University of Russia (Russian Federation); Zol’nikova, N. N. [Russian Academy of Sciences, Space Research Institute (Russian Federation); Erokhin, N. S. [People’s Friendship University of Russia (Russian Federation)

    2016-01-15

    Based on the numerical solution of the nonlinear nonstationary second-order equation for the wave phase on the particle trajectory, the dynamics of surfatron acceleration of electrons by an electromagnetic wave propagating across the external magnetic field in space plasma is analyzed as a function of the electron momentum along the wave front. Numerical calculations show that, for strongly relativistic initial values of the electron momentum component along the wave front g{sub y}(0) (the other parameters of the problem being the same), electrons are trapped into the regime of ultrarelativistic surfatron acceleration within a certain interval of the initial wave phase Ψ(0) on the particle trajectory. It is assumed in the calculations that vertical bar Ψ(0) vertical bar ≤ π. For strongly relativistic values of g{sub y}(0), electrons are immediately trapped by the wave for 19% of the initial values of the phase Ψ(0) (favorable phases). For the rest of the values of Ψ(0), trapping does not occur even at long times. This circumstance substantially simplifies estimations of the wave damping due to particle acceleration in subsequent calculations. The dynamics of the relativistic factor and the components of the electron velocity and momentum under surfatron acceleration is also analyzed. The obtained results are of interest for the development of modern concepts of possible mechanisms of generation of ultrarelativistic particle fluxes in relatively calm space plasma, as well as for correct interpretation of observational data on the fluxes of such particles and explanation of possible reasons for the deviation of ultrarelativistic particle spectra detected in the heliosphere from the standard power-law scalings and the relation of these variations to space weather and large-scale atmospheric processes similar to tropical cyclones.

  17. Oscillations of the Chromatic States and Accelerated Expansion of the Universe

    Directory of Open Access Journals (Sweden)

    Quznetsov G.

    2010-04-01

    Full Text Available It is known (Quznetsov G. Higgsless Glashow’s and quark-gluon theories and gravity without superstrings. Progress in Physics , 2009, v. 3, 32–40 that probabilities of point- like events are defined by some generalization of Dirac’s equation. One part of such generalized equation corresponds to the Dirac’s leptonic equation, and the other part corresponds to the Dirac’s quark equation. The quark part of this equation is invariant under the oscillations of chromatic states. And it turns out that these oscillations bend space-time so that at large distances the space expands with acceleration according to Hubble’s law.

  18. Joint International Accelerator School

    CERN Multimedia

    CERN Accelerator School

    2014-01-01

    The CERN and US Particle Accelerator Schools recently organised a Joint International Accelerator School on Beam Loss and Accelerator Protection, held at the Hyatt Regency Hotel, Newport Beach, California, USA from 5-14 November 2014. This Joint School was the 13th in a series of such schools, which started in 1985 and also involves the accelerator communities in Japan and Russia.   Photo courtesy of Alfonse Pham, Michigan State University.   The school attracted 58 participants representing 22 different nationalities, with around half from Europe and the other half from Asia and the Americas. The programme comprised 26 lectures, each of 90 minutes, and 13 hours of case study. The students were given homework each day and had an opportunity to sit a final exam, which counted towards university credit. Feedback from the participants was extremely positive, praising the expertise and enthusiasm of the lecturers, as well as the high standard and quality of their lectures. Initial dis...

  19. Proof-of-principle demonstration of a virtual flow meter-based transducer for gaseous helium monitoring in particle accelerator cryogenics.

    Science.gov (United States)

    Arpaia, P; Blanco, E; Girone, M; Inglese, V; Pezzetti, M; Piccinelli, F; Serio, L

    2015-07-01

    A transducer based on a virtual flow meter is proposed for monitoring helium distribution and consumption in cryogenic systems for particle accelerators. The virtual flow meter allows technical and economical constraints, preventing installation of physical instruments in all the needed measurement points, to be overcome. Virtual flow meter performance for the alternative models of Samson [ http://www.samson.de (2015)] and Sereg-Schlumberger [ http://www.slb.com/ (2015)] is compared with the standard IEC 60534-2-1 [Industrial-process control valves-Part 2-1: Flow capacity-sizing equations for fluid flow under installed conditions (2011), https://webstore.iec.ch/publication/2461], for a large temperature range, for both gaseous and liquid helium phases, and for different pressure drops. Then, the calibration function of the transducer is derived. Finally, the experimental validation for the helium gaseous state on the test station for superconducting magnets in the laboratory SM18 [Pirotte et al., AIP Conf. Proc. 1573, 187 (2014)] at CERN is reported.

  20. Speeding up CRMs for cloud-climate interaction studies by acceleration of mean state tendencies

    Science.gov (United States)

    Jones, C. R.; Bretherton, C. S.

    2014-12-01

    Cloud-resolving models (CRMs) are routinely used to simulate boundary-layer and deep convective cloud processes, aid in the development of moist physical parameterization for global models, study cloud-climate feedbacks and cloud-aerosol interaction, and as the heart of superparameterized climate models. CRMs are computationally demanding, placing practical constraints on their use in these applications, especially for long, climate-relevant simulations. In many situations, the horizontal-mean atmospheric structure evolves slowly compared to the turnover time of the most energetic turbulent eddies. We use this time scale separation to accelerate the time-integration of a CRM, the System for Atmospheric Modelling. Our approach uses a large time step to evolve the horizontally averaged state variables, followed by a short time step to calculate the turbulent fluctuations about the mean state. Using this approach, we are able to accelerate the model evolution by a factor of 8 or more in idealized stratocumulus, shallow and deep cumulus convection without substantial loss of accuracy in simulating mean cloud statistics and their sensitivity to climate change perturbations. We show how to adapt the approach to challenges arising from rapidly falling precipitation and from advecting scalars with a variety of lifetimes.

  1. Research in elementary particle physics. [Ohio State Univ. , Columbus

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Experimental and theoretical work on high energy physics is reviewed. Included are preparations to study high-energy electron-proton interactions at HERA, light-cone QCD, decays of charm and beauty particles, neutrino oscillation, electron-positron interactions at CLEO II, detector development, and astrophysics and cosmology.

  2. DECELERATION OF ELECTRON VE LOCITY BASED ON THE WAVE- PARTICLE DUALITY LEADS TO RE LATIVE TIME ACCELERATION: HYPOTHESIS OF INCREASED BIOPHYSICAL REACTION VELOCITY

    Directory of Open Access Journals (Sweden)

    Horst Koch

    2013-03-01

    Full Text Available The high speed of biological processes such as photosynthesis, enzymatic reactions or neuronal activity cannot completely be explained on the basis of classic physical approaches. Different quantum biology effects such as tunnelling have been postulated. We hypothetically admit that deceleration of electron velocity based on light-particle duality of electrons leads to time acceleration. Deceleration from the status of light towards a status of a particle may therefore speed up biochemical or biophysical reactions in the atomic or molecular dimension. Electrophysiological and biological phenomena are discussed on the basis of the hypothesis

  3. Oscillator Models and Collective Motion: Splay State Stabilization of Self-Propelled Particles

    OpenAIRE

    Paley, Derek; Leonard, Naomi; Sepulchre, Rodolphe

    2005-01-01

    This paper presents a Lyapunov design for the stabilization of collective motion in a planar kinematic model of N particles moving at constant speed. We derive a control law that achieves asymptotic stability of the splay state formation, characterized by uniform rotation of N evenly spaced particles on a circle. In designing the control law, the particle headings are treated as a system of coupled phase oscillators. The coupling function which exponentially stabilizes th...

  4. Accelerator experiments with soft protons and hyper-velocity dust particles: application to ongoing projects of future X-ray missions

    DEFF Research Database (Denmark)

    Perinati, E.; Diebold, S.; Kendziorra, E.

    2012-01-01

    We report on our activities, currently in progress, aimed at performing accelerator experiments with soft protons and hyper-velocity dust particles. They include tests of different types of X-ray detectors and related components (such as filters) and measurements of scattering of soft protons...... and hyper-velocity dust particles off X-ray mirror shells. These activities have been identified as a goal in the context of a number of ongoing space projects in order to assess the risk posed by environmental radiation and dust and qualify the adopted instrumentation with respect to possible damage...... or performance degradation. In this paper we focus on tests for the Silicon Drift Detectors (SDDs) used aboard the LOFT space mission. We use the Van de Graaff accelerators at the University of T\\"ubingen and at the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg, for soft proton and hyper...

  5. Mechanism for the acceleration of particles and emission of short-wavelength electromagnetic radiation in high-current plasmadynamic discharges in a magnetoplasma compressor

    Science.gov (United States)

    Kozlov, N. P.; Protasov, Iu. S.

    1981-09-01

    Measurements are presented of the spatial and temporal distribution of fast particles, high energy photon fluxes and current fields in the accelerator channel and ejected current region of a magnetoplasma compressor. These data are used as the bases of conclusions concerning the position of the acceleration zones and the macroscopic structure of the current-plasma shell during the emission of the fast particles. Since it is a nonconservative multiparameter system, the magnetoplasma compressor allows investigation of the emission, spatial and temporal characteristics of the X-ray emission through changes in the dynamics of the current-plasma shell, or, equivalently, by changing the dynamics, geometry and spatial position of the neutral current sheets.

  6. Development of a charged particle multidetector and application to physics at the Vivitron accelerator; Elaboration d`un multidetecteur de particules chargees et application a la physique aupres de l`accelerateur vivitron

    Energy Technology Data Exchange (ETDEWEB)

    Belier, G.

    1994-05-01

    The charged particle multidetector ICARE is an apparatus designed for the Vivitron accelerator, with the aim to study both heavy ions reaction mechanisms and the structure of the nuclei. It will be able to work independently with its own electronic and acquisition system as well as in association with other types of multidetectors (Eurogam, Demon, ...). The development of ICARE is based on compactness and modularity criteria and takes into account the expected multiplicities and energies of the particles to be detected. It is composed of 48 compact telescopes of low energy threshold, 8 of them being heavy ion telescopes (Z < or = 40) and the others devoted to light charged particles (Z < or = to 3) detection. 16 of these can work in the forward region (between 0 degree and the grazing angle) where particles are generally the most energetic. Multiwire proportional counters have been used to look for fission of {sup 147}Gd superdeformed states of highest angular momenta. In the gamma ray spectra detected by the Eurogam array in coincidence with fission fragments, a positive contribution corresponding to energy differences are observed, which are consistent with the emission by superdeformed states. (from author) 64 figs., 12 tabs., 91 refs.

  7. LAVENDER: A steady-state core analysis code for design studies of accelerator driven subcritical reactors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shengcheng; Wu, Hongchun; Cao, Liangzhi; Zheng, Youqi, E-mail: yqzheng@mail.xjtu.edu.cn; Huang, Kai; He, Mingtao; Li, Xunzhao

    2014-10-15

    Highlights: • A new code system for design studies of accelerator driven subcritical reactors (ADSRs) is developed. • S{sub N} transport solver in triangular-z meshes, fine deletion analysis and multi-channel thermal-hydraulics analysis are coupled in the code. • Numerical results indicate that the code is reliable and efficient for design studies of ADSRs. - Abstract: Accelerator driven subcritical reactors (ADSRs) have been proposed and widely investigated for the transmutation of transuranics (TRUs). ADSRs have several special characteristics, such as the subcritical core driven by spallation neutrons, anisotropic neutron flux distribution and complex geometry etc. These bring up requirements for development or extension of analysis codes to perform design studies. A code system named LAVENDER has been developed in this paper. It couples the modules for spallation target simulation and subcritical core analysis. The neutron transport-depletion calculation scheme is used based on the homogenized cross section from assembly calculations. A three-dimensional S{sub N} nodal transport code based on triangular-z meshes is employed and a multi-channel thermal-hydraulics analysis model is integrated. In the depletion calculation, the evolution of isotopic composition in the core is evaluated using the transmutation trajectory analysis algorithm (TTA) and fine depletion chains. The new code is verified by several benchmarks and code-to-code comparisons. Numerical results indicate that LAVENDER is reliable and efficient to be applied for the steady-state analysis and reactor core design of ADSRs.

  8. Colour particle states behaviour in the QCD vacuum

    Directory of Open Access Journals (Sweden)

    Kuvshinov V.I.

    2016-01-01

    The behaviour of squeezed and entangled quantum states, the interaction of colour superpositions and multiparticle states with stochastic QCD vacuum is described. It is shown that it leads to a fully mixed quantum state with equal probabilities for different colours. Decoherence rate is found to be proportional to the product of the distance between colour charges and the time during which this interaction has taken place. I.e. such an interaction seems to lead naturally to confinement of quarks.

  9. How elementary paticles are discovered. From the cyclotron to the LHC - an expedition through the world of the particle accelerators; Wie man Elementarteilchen entdeckt. Vom Zyklotron zum LHC - ein Streifzug durch die Welt der Teilchenbeschleuniger

    Energy Technology Data Exchange (ETDEWEB)

    Freytag, Carl; Osterhage, Wolfgang W.

    2016-07-01

    This book explains the physical foundations and the technology of the elementary-particle research and describes the particle accelerators, the detector, and their concerted acting. On some milestones of the research - from the production of transuranium elements via the discovery of exotic mesons until the Higgs particle - the way from theory via the experiment to the research result is shown.

  10. Accelerated Gillespie Algorithm for Gas–Grain Reaction Network Simulations Using Quasi-steady-state Assumption

    Science.gov (United States)

    Chang, Qiang; Lu, Yang; Quan, Donghui

    2017-12-01

    Although the Gillespie algorithm is accurate in simulating gas–grain reaction networks, so far its computational cost is so expensive that it cannot be used to simulate chemical reaction networks that include molecular hydrogen accretion or the chemical evolution of protoplanetary disks. We present an accelerated Gillespie algorithm that is based on a quasi-steady-state assumption with the further approximation that the population distribution of transient species depends only on the accretion and desorption processes. The new algorithm is tested against a few reaction networks that are simulated by the regular Gillespie algorithm. We found that the less likely it is that transient species are formed and destroyed on grain surfaces, the more accurate the new method is. We also apply the new method to simulate reaction networks that include molecular hydrogen accretion. The results show that surface chemical reactions involving molecular hydrogen are not important for the production of surface species under standard physical conditions of dense molecular clouds.

  11. Optimization of solid state fermentation of sugar cane by Aspergillus niger considering particles size effect

    Energy Technology Data Exchange (ETDEWEB)

    Echevarria, J.; Rodriguez, L.J.A.; Delgado, G. (Instituto Cubano de Investigaciones de los Derivados de la Cana de Azucar (ICIDCA), La Habana (Cuba)); Espinosa, M.E. (Centro Nacional de Investigaciones Cientificas, La Habana (Cuba))

    1991-01-01

    The protein enrichment of sugar cane by solid state fermentation employing Aspergillus niger was optimized in a packed bed column using a two Factor Central Composit Design {alpha} = 2, considering as independent factors the particle diameter corresponding to different times of grinding for a sample and the air flow rate. It was significative for the air flow rate (optimum 4.34 VKgM) and the particle diameter (optimum 0.136 cm). The average particle size distribution, shape factor, specific surface, volume-surface mean diameter, number of particles, real and apparent density and holloweness for the different times of grinding were determined, in order to characterize the samples. (orig.).

  12. LINEAR ACCELERATOR

    Science.gov (United States)

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  13. Collective and single particle states in medium mass vibrational nuclei

    CERN Document Server

    Suliman, G

    2001-01-01

    The particle-core coupling model has been employed to describe the low lying nuclear excitations in the vibrational odd-A nuclei. In the frame of this model the following observables were calculated: excitation energies, spin and parity quantum numbers, electric quadrupole moments, magnetic dipole moments and reduced transition probabilities. Two computer codes were employed. The first one, PCOREC, diagonalized the Hamiltonian providing the eigenvectors and eigenvalues. The second one, PCORECTR, starts from the eigenvector computer by the first program and computes the observables which are compared we results of experiments. A good description of the experimental data has been obtained for the sup 1 sup 3 sup 3 Sb, sup 1 sup 2 sup 3 Sb and sup 1 sup 2 sup 5 Sb nuclei. (authors)

  14. Equilibrium state of a cylindrical particle with flat ends in nematic liquid crystals.

    Science.gov (United States)

    Hashemi, S Masoomeh; Ejtehadi, Mohammad Reza

    2015-01-01

    A continuum theory is employed to numerically study the equilibrium orientation and defect structures of a circular cylindrical particle with flat ends under a homeotropic anchoring condition in a uniform nematic medium. Different aspect ratios of this colloidal geometry from thin discotic to long rodlike shapes and several colloidal length scales ranging from mesoscale to nanoscale are investigated. We show that the equilibrium state of this colloidal geometry is sensitive to the two geometrical parameters: aspect ratio and length scale of the particle. For a large enough mesoscopic particle, there is a specific asymptotic equilibrium angle associated to each aspect ratio. Upon reducing the particle size to nanoscale, the equilibrium angle follows a descending or ascending trend in such a way that the equilibrium angle of a particle with the aspect ratio bigger than 1:1 (a discotic particle) goes to a parallel alignment with respect to the far-field nematic, whereas the equilibrium angle for a particle with the aspect ratio 1:1 and smaller (a rodlike particle) tends toward a perpendicular alignment to the uniform nematic direction. The discrepancy between the equilibrium angles of the mesoscopic and nanoscopic particles originates from the significant differences between their defect structures. The possible defect structures related to mesoscopic and nanoscopic colloidal particles of this geometry are also introduced.

  15. Kinetics of accelerated solid-state fermentation of organic-rich municipal solid waste.

    Science.gov (United States)

    Viéitez, E R; Mosquera, J; Ghosh, S

    2000-01-01

    Biotransformation of landfill solid wastes is a slow process requiring decades for completion. Accelerated anaerobic fermentation in modulated landfill environments may alleviate or eliminate pollution of land, water and air. This research was undertaken to demonstrate the application of biphasic fermentation to a simulated laboratory-scale landfill to effect rapid biomethanation of biodegradable solids. The biphasic process consisted of solid-state, acidogenic fermentation of the organic fraction of MSW followed by biomethanation of acidic hydrolysates in a separate methane fermenter. Solid-state fermentation of the MSW with effluent recirculation resulted in rapid hydrolysis, acidification and denitrification, with soluble COD and VFA concentrations accumulating to inhibitory levels of 60,000 mg/l and 13,000 mg/l, respectively, at a pH of 4.5. The landfill gas methane concentration reached a maximum of 55 mol.%. By comparison, the methanogenic reactor produced high methane-content (70-85 mol.%) gases. The biphasic process effected carbohydrate, lipid, and protein conversion efficiencies of 90%, 49%, and 37%, respectively. Development of a Monod-type product-formation model was undertaken to predict methane formation and to determine kinetic parameters for the methanogenic processes in the simulated landfill and separate methane reactors. A first-order solids hydrolysis rate constant of 0.017 day-1 was evaluated to show that landfill solids hydrolysis was slower than the inhibited methanogenesis rate.

  16. Majorana Fermions in Particle Physics, Solid State and Quantum Information

    Science.gov (United States)

    Borsten, L.; Duff, M. J.

    This review is based on lectures given by M. J. Duff summarising the far reaching contributions of Ettore Majorana to fundamental physics, with special focus on Majorana fermions in all their guises. The theoretical discovery of the eponymous fcrmion in 1937 has since had profound implications for particlc physics, solid state and quantum computation. The breadth of these disciplines is testimony to Majorana's genius, which continues to permeate physics today. These lectures offer a whistle-stop tour through some limited subset of the key ideas. In addition to touching on these various applications, we will draw out some fascinating relations connecting the normed division algebras R, ℂ, H, O to spinors, trialities. K-theory and the classification of stable topological states of symmetry-protected gapped free-fermion systems.

  17. A glimpse of the 'God particle'? Scientists pushed Europe's premier particle accelerator to the threshold of a fundamental breakthrough. Then they pulled the plug

    CERN Multimedia

    Morton, O

    2000-01-01

    The decision hung on the most slender of majorities; the data were recounted and reanalyzed exhaustively; tempers flared; appeals were made; committees few people have ever heard of had their say. But in the end the accelerator's fate was sealed and a chance for physicists to solve one of the basic mysteries of the universe was forgone (1 page).

  18. The Accelerator Reliability Forum

    CERN Document Server

    Lüdeke, Andreas; Giachino, R

    2014-01-01

    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  19. Research on the method of information system risk state estimation based on clustering particle filter

    Science.gov (United States)

    Cui, Jia; Hong, Bei; Jiang, Xuepeng; Chen, Qinghua

    2017-05-01

    With the purpose of reinforcing correlation analysis of risk assessment threat factors, a dynamic assessment method of safety risks based on particle filtering is proposed, which takes threat analysis as the core. Based on the risk assessment standards, the method selects threat indicates, applies a particle filtering algorithm to calculate influencing weight of threat indications, and confirms information system risk levels by combining with state estimation theory. In order to improve the calculating efficiency of the particle filtering algorithm, the k-means cluster algorithm is introduced to the particle filtering algorithm. By clustering all particles, the author regards centroid as the representative to operate, so as to reduce calculated amount. The empirical experience indicates that the method can embody the relation of mutual dependence and influence in risk elements reasonably. Under the circumstance of limited information, it provides the scientific basis on fabricating a risk management control strategy.

  20. Research on the method of information system risk state estimation based on clustering particle filter

    Directory of Open Access Journals (Sweden)

    Cui Jia

    2017-05-01

    Full Text Available With the purpose of reinforcing correlation analysis of risk assessment threat factors, a dynamic assessment method of safety risks based on particle filtering is proposed, which takes threat analysis as the core. Based on the risk assessment standards, the method selects threat indicates, applies a particle filtering algorithm to calculate influencing weight of threat indications, and confirms information system risk levels by combining with state estimation theory. In order to improve the calculating efficiency of the particle filtering algorithm, the k-means cluster algorithm is introduced to the particle filtering algorithm. By clustering all particles, the author regards centroid as the representative to operate, so as to reduce calculated amount. The empirical experience indicates that the method can embody the relation of mutual dependence and influence in risk elements reasonably. Under the circumstance of limited information, it provides the scientific basis on fabricating a risk management control strategy.