WorldWideScience

Sample records for blowup particle beams

  1. PARTICLE BEAM TRACKING CIRCUIT

    Science.gov (United States)

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  2. Charged particle beams

    CERN Document Server

    Humphries, Stanley

    2013-01-01

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

  3. QUENCHING VERSUS BLOW-UP

    Institute of Scientific and Technical Information of China (English)

    Deng Keng; Zhao Chenglin

    2000-01-01

    This paper is concerned with the semilinear heat equation ut = Δu -u-q in Ω × (0, T) under the nonlinear boundary condition × (0, T).Criteria for finite time quenching and blow-up are established, quenching and blow-up sets are discussed, and the rates of quenching and blow-up are obtained.

  4. Particle beam injector system and method

    Science.gov (United States)

    Guethlein, Gary

    2013-06-18

    Methods and devices enable coupling of a charged particle beam to a radio frequency quadrupole accelerator. Coupling of the charged particle beam is accomplished, at least in-part, by relying on of sensitivity of the input phase space acceptance of the radio frequency quadrupole to the angle of the input charged particle beam. A first electric field across a beam deflector deflects the particle beam at an angle that is beyond the acceptance angle of the radio frequency quadrupole. By momentarily reversing or reducing the established electric field, a narrow portion of the charged particle beam is deflected at an angle within the acceptance angle of the radio frequency quadrupole. In another configuration, beam is directed at an angle within the acceptance angle of the radio frequency quadrupole by the first electric field and is deflected beyond the acceptance angle of the radio frequency quadrupole due to the second electric field.

  5. Quantum mechanical formalism of particle beam optics

    OpenAIRE

    Khan, Sameen Ahmed

    2001-01-01

    A general procedure for construction of the formalism of quantum beam optics for any particle is reviewed. The quantum formalism of spin-1/2 particle beam optics is presented starting {\\em ab initio} with the Dirac equation. As an example of application the case of normal magnetic quadrupole lens is discussed. In the classical limit the quantum formalism leads to the well-known Lie algebraic formalism of classical particle beam optics.

  6. Beam dynamics in high energy particle accelerators

    CERN Document Server

    Wolski, Andrzej

    2014-01-01

    Particle accelerators are essential tools for scientific research in fields as diverse as high energy physics, materials science and structural biology. They are also widely used in industry and medicine. Producing the optimum design and achieving the best performance for an accelerator depends on a detailed understanding of many (often complex and sometimes subtle) effects that determine the properties and behavior of the particle beam. Beam Dynamics in High Energy Particle Accelerators provides an introduction to the concepts underlying accelerator beam line design and analysis, taking an approach that emphasizes the elegance of the subject and leads into the development of a range of powerful techniques for understanding and modeling charged particle beams.

  7. Single Gradientless Light Beam Drags Particles as Tractor Beams

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Qiu, Cheng-Wei; Wang, Haifeng

    2011-01-01

    Usually a light beam pushes a particle when the photons act upon it. We investigate the optical forces by nonparaxial gradientless beams and find that the forces can drag suitable particles all the way towards the light source. The major criterion of realizing the backward dragging force is the s...

  8. On Blowup in Supercritical Wave Equations

    Science.gov (United States)

    Donninger, Roland; Schörkhuber, Birgit

    2016-03-01

    We study the blowup behavior for the focusing energy-supercritical semilinear wave equation in 3 space dimensions without symmetry assumptions on the data. We prove the stability in {H^2× H^1} of the ODE blowup profile.

  9. Full Counting Statistics of Stationary Particle Beams

    CERN Document Server

    Kiukas, J; Werner, R F

    2010-01-01

    We present a general scheme for treating particle beams, including stationary beams, as many particle systems. This includes the full counting statistics and the requirements of Bose/Fermi symmetry. We treat in detail a model of a source, creating particles in a fixed state, which then evolve under the free time evolution, and we determine the resulting stationary beam in the far field. In comparison to the one-particle picture we obtain a correction from Bose/Fermi statistics, which depends on the emission rate.

  10. Quality assurance for particle beam therapy

    International Nuclear Information System (INIS)

    In radiation therapy, it is essential that a prescribed target area is irradiated with the prescribed dose concentration to reduce the possibility cancer reoccurrence or to mitigate its side effects. Particle beam therapy is a high accuracy radiation therapy, which has superior characteristics. Specifically, a high dose region, namely, Bragg peak formed around the beam stopping point can be adjusted to the target volume. The routine of particle beam therapy should be performed with various verifications, called quality assurance(QA), at its each step, i.e., treatment planning, dosimetry, patient positioning and respiratory gating system. Each particle beam therapy facility should have and conduct its own QA program. Methods and materials for the QA should be developed according to the progress of techniques in particle beam therapy. (author)

  11. Underdense plasma lenses for focusing particle beams

    International Nuclear Information System (INIS)

    Plasma lenses are of interest for providing ultra-strong focusing of particle beams in order to enhance the luminosity of a high-energy linear collider. Previous work has explored the selfpinch of e+ or e- beams as they pass through an overdense slab of passive plasma (i.e., plasma density much greater than the beam density). Here the authors examine the focusing of beams in an underdense plasma through physical and particle simulation models. In this regime the plasma dynamics becomes highly non-linear and differs for e+ and e- beams. For e- beams the plasma electrons are almost completely expelled by the beam's space charge leaving a uniform column of ion charge that provides the focusing force. Compared to the overdense lens, the underdense lens has the advantages that spherical aberrations, longitudinal aberrations, and plasma contribution to background in the detectors are all greatly reduced. 10 refs., 4 figs., 1 tab

  12. Plasma lenses for focusing particle beams

    International Nuclear Information System (INIS)

    The focusing of particles by a thin plasma lens is analyzed with physical, linearized fluid and particle-in-cell computational models. For parameters similar to next-generation linear colliders, the plasma lens strength can exceed 100 MG/cm, and the luminosity can be enhanced by an order of magnitude by passing each beam through an appropriate plasma slab. The plasma electrons affect the focusing by shifting so as to (partially or completely) charge neutralize the beam. Both overdense and underdense plasma lenses are described (plasma density n0 greater or less than beam density nb). The former case applies equally well to e+ and e- beams, while the latter has distinct advantages for e- beams (including smaller aberrations and background). The effects of spherical and longitudinal aberrations, emittance, plasma boundaries, and non-linear-plasma dynamics on the final spot size are discussed

  13. Particle beam fusion progress report January 1979 through June 1979

    International Nuclear Information System (INIS)

    The following chapters are included: (1) fusion target studies, (2) target experiments, (3) particle beam source development, (4) particle beam experiments, (5) pulsed power research and development, (6) pulsed fusion applications, and (7) electron beam fusion accelerator project

  14. Tumour Therapy with Particle Beams

    OpenAIRE

    Grupen, C.

    2000-01-01

    Photons are exponentially attenuated in matter producing high doses close to the surface. Therefore they are not well suited for the treatment of deep seated tumours. Charged particles, in contrast, exhibit a sharp increase of ionisation density close to the end of their range, the so-called Bragg-peak. The depth of the Bragg-peak can be adjusted by varying the particle's energy. In parallel with the large energy deposit the increase in biological effectiveness for cell killing at the end of ...

  15. Method for charged particle beam acceleration

    International Nuclear Information System (INIS)

    The method of charged particle beam acceleration based on its resonance interaction with electromagnetic field of travelling wave is suggested. The electron beam is injected into waveguide in which longitudinal magnetic field and electromagnetic wave are excited. With the purpose of reducing HF-power losses in the waveguide walls, the azimuthal particle motion is synchronized with azimuthal change of longitudinal component of electric field of the accelerating electromagnetic wave. The suggested method permits to increase the efficiency and shunting resistance of the accelerating waveguide by reducing its boundary surface

  16. Beam Line: 100 years of elementary particles

    Science.gov (United States)

    Pais, A.; Weinberg, S.; Quigg, C.; Riordan, M.; Panofsky, W. K. H.

    1997-04-01

    This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe.

  17. Blow-up regimes in the $\\mathcal{PT}$- and the $\\mathcal{AC}$-dimer

    CERN Document Server

    Barashenkov, I V; Flach, S

    2013-01-01

    In the actively coupled ($\\mathcal{AC}$) pair of waveguides, the growth of small perturbations is saturated by the focussing nonlinearity that couples the linearly growing to the linearly damped mode. On the other hand, in the $\\mathcal{PT}$-symmetric coupler, the focussing nonlinearity promotes the blowup of stationary light beams. The purpose of this study is to compare the nonlinear dynamics and explain the opposite effect of the same nonlinearity in the two systems. We show that while the blowup regimes are stable in the $\\mathcal{PT}$-symmetric pair of waveguides, they are unstable and hence cannot be observed in the $\\mathcal{AC}$-dimer.

  18. Blowups of Heterotic Orbifolds using Toric Geometry

    CERN Document Server

    Nibbelink, Stefan Groot

    2007-01-01

    Heterotic orbifold models are promising candidates for models with MSSM like spectra. But orbifolds only correspond to a special place in moduli space, the bigger picture is described by the moduli space of Calabi-Yau spaces. In this talk we will make explicit connections between both points of view. To this end we study blowups of orbifold singularities using both explicit constructions and toric geometry techniques. We show that matching of all orbifold models in blowups are possible.

  19. Blow-up: A Free Lunch?

    Directory of Open Access Journals (Sweden)

    Jan Koenderink

    2012-02-01

    Full Text Available We consider operations that change the size of images, either shrinks or blow-ups. Image processing offers numerous possibilities, put at everyone's disposal with such computer programs as Adobe Photoshop. We consider a different class of operations, aimed at immediate visual awareness, rather than pixel arrays. We demonstrate cases of blow-ups that do not sacrifice apparent resolution. This apparent information gain is due to “amodal occlusion.”

  20. Theory and design of charged particle beams

    CERN Document Server

    Reiser, Martin

    1994-01-01

    Although particle accelerators are the book's main thrust, it offers a broad synoptic description of beams which applies to a wide range of other devices such as low-energy focusing and transport systems and high-power microwave sources. Develops material from first principles, basic equations and theorems in a systematic way. Assumptions and approximations are clearly indicated. Discusses underlying physics and validity of theoretical relationships, design formulas and scaling laws. Features a significant amount of recent work including image effects and the Boltzmann line charge density prof

  1. Charged particle beam current monitoring tutorial

    International Nuclear Information System (INIS)

    A tutorial presentation is made on topics related to the measurement of charged particle beam currents. The fundamental physics of electricity and magnetism pertinent to the problem is reviewed. The physics is presented with a stress on its interpretation from an electrical circuit theory point of view. The operation of devices including video pulse current transformers, direct current transformers, and gigahertz bandwidth wall current style transformers is described. Design examples are given for each of these types of devices. Sensitivity, frequency response, and physical environment are typical parameters which influence the design of these instruments in any particular application. Practical engineering considerations, potential pitfalls, and performance limitations are discussed

  2. Particle beam fusion progress report, January-June 1980

    International Nuclear Information System (INIS)

    An overview and technical summaries are given for research progress in each of the following general areas: (1) fusion target studies; (2) target experiments; (3) particle beam source theory; (4) diagnostics development; (5) particle beam experiments; (6) pulsed power research and development; (7) pulse power application; and (8) Electron Beam Fusion Accelerator project

  3. Manipulation of dielectric particles with nondiffracting parabolic beams.

    Science.gov (United States)

    Ortiz-Ambriz, Antonio; Gutiérrez-Vega, Julio C; Petrov, Dmitri

    2014-12-01

    The trapping and manipulation of microscopic particles embedded in the structure of nondiffracting parabolic beams is reported. The particles acquire orbital angular momentum and exhibit an open trajectory following the parabolic fringes of the beam. We observe an asymmetry in the terminal velocity of the particles caused by the counteracting gradient and scattering forces.

  4. QUANTUM COHOMOLOGY OF BLOWUPS OF SURFACES AND ITS FUNCTORIALITY PROPERTY

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this article, using the WDVV equation, the author first proves that all Gromov-Witten invariants of blowups of surfaces can be computed from the Gromov-Witten invariants of itself by some recursive relations. Furthermore, it may determine the quantum product on blowups. It also proves that there is some degree of functoriality of the big quantum cohomology for a blowup.

  5. Coherent States for Particle Beams in the Thermal Wave Model

    OpenAIRE

    De Nicola, S.; Fedele, R.; Man'ko, V. I.; Miele, G.

    1995-01-01

    In this paper, by using an analogy among {\\it quantum mechanics}, {\\it electromagnetic beam optics in optical fibers}, and {\\it charge particle beam dynamics}, we introduce the concept of {\\it coherent states} for charged particle beams in the framework of the {\\it Thermal Wave Model} (TWM). We give a physical meaning of the Gaussian-like coherent structures of charged particle distribution that are both naturally and artificially produced in an accelerating machine in terms of the concept of...

  6. Charged particle acceleration by electron beam in corrugated plasma waveguide

    International Nuclear Information System (INIS)

    A two-beam charged particle acceleration scheme in a plasma waveguide with corrugated conducting walls is considered. The guiding heavy-current relativistic electron beam is in synchronism with the first plasma wave space harmonics and the accelerated beam is synchronism with a quicker plasma wave. In this case under weak corrugation of the wall the accelerating resonance field effecting the accelerated particles notably increases the field braking the guiding beam. The process of plasma wave excitation with regard to the guiding beam space charge and the relativistic particle acceleration dynamics are investigated by numeric methods. Optimal acceleration modes are found. 19 refs.; 12 figs

  7. Charged-particle beam: a safety mandate

    International Nuclear Information System (INIS)

    The Advanced Test Accelerator (ATA) is a recent development in the field of charged particle beam research at Lawrence Livermore National Laboratory. With this experimental apparatus, researchers will characterize intense pulses of electron beams propagated through air. Inherent with the ATA concept was the potential for exposure to hazards, such as high radiation levels and hostile breathing atmospheres. The need for a comprehensive safety program was mandated; a formal system safety program was implemented during the project's conceptual phase. A project staff position was created for a safety analyst who would act as a liaison between the project staff and the safety department. Additionally, the safety analyst would be responsible for compiling various hazards analyses reports, which formed the basis of th project's Safety Analysis Report. Recommendations for safety features from the hazards analysis reports were incorporated as necessary at appropriate phases in project development rather than adding features afterwards. The safety program established for the ATA project faciliated in controlling losses and in achieving a low-level of acceptable risk

  8. 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.

  9. Plasma focusing and diagnosis of high energy particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pisin.

    1990-09-01

    Various novel concepts of focusing and diagnosis of high energy charged particle beams, based on the interaction between the relativistic particle beam and the plasma, are reviewed. This includes overdense thin plasma lenses, and (underdense) adiabatic plasma lens, and two beam size monitor concepts. In addition, we introduce another mechanism for measuring flat beams based on the impulse received by heavy ions in an underdense plasma. Theoretical investigations show promise of focusing and diagnosing beams down to sizes where conventional methods are not possible to provide. 21 refs.

  10. Light emission from particle beam induced plasma - An overview

    CERN Document Server

    Ulrich, A

    2015-01-01

    Experiments to study the light emission from plasma produced by particle beams are presented. Fundamental aspects in comparison with discharge plasma formation are discussed. It is shown that the formation of excimer molecules is an important process. This paper summarizes various studies of particle beam induced light emission and presents first results of a direct comparison of light emission induced by electron- and ion beam excitation. Both high energy heavy ion beam and low energy electron beam experiments are described and an overview over applications in the form of light sources, lasers, and ionization devices is given.

  11. Beam-beam simulation code BBSIM for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab

    2011-01-01

    A highly efficient, fully parallelized, six-dimensional tracking model for simulating interactions of colliding hadron beams in high energy ring colliders and simulating schemes for mitigating their effects is described. The model uses the weak-strong approximation for calculating the head-on interactions when the test beam has lower intensity than the other beam, a look-up table for the efficient calculation of long-range beam-beam forces, and a self-consistent Poisson solver when both beams have comparable intensities. A performance test of the model in a parallel environment is presented. The code is used to calculate beam emittance and beam loss in the Tevatron at Fermilab and compared with measurements. They also present results from the studies of stwo schemes proposed to compensate the beam-beam interactions: (a) the compensation of long-range interactions in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven and the Large Hadron Collider (LHC) at CERN with a current carrying wire, (b) the use of a low energy electron beam to compensate the head-on interactions in RHIC.

  12. Blow-up: A free lunch?

    NARCIS (Netherlands)

    Koenderink, J.J.; Richards, W.; Van Doorn, A.J.

    2012-01-01

    We consider operations that change the size of images, either shrinks or blow-ups. Image processing offers numerous possibilities, put at everyone’s disposal with such computer programs as Adobe Photoshop. We consider a different class of operations, aimed at immediate visual awareness, rather than

  13. A hypergraph blow-up lemma

    CERN Document Server

    Keevash, Peter

    2010-01-01

    We obtain a hypergraph generalisation of the graph blow-up lemma proved by Komlos, Sarkozy and Szemeredi, showing that hypergraphs with sufficient regularity and no atypical vertices behave as if they were complete for the purpose of embedding bounded degree hypergraphs.

  14. Beaming of particles and synchrotron radiation in relativistic magnetic reconnection

    CERN Document Server

    Kagan, Daniel; Piran, Tsvi

    2016-01-01

    Relativistic reconnection has been invoked as a mechanism for particle acceleration in numerous astrophysical systems. According to idealised analytical models reconnection produces a bulk relativistic outflow emerging from the reconnection sites (X-points). The resulting radiation is therefore highly beamed. Using two-dimensional particle-in-cell (PIC) simulations, we investigate particle and radiation beaming, finding a very different picture. Instead of having a relativistic average bulk motion with isotropic electron velocity distribution in its rest frame, we find that the bulk motion of particles in X-points is similar to their Lorentz factor gamma, and the particles are beamed within about 5/gamma. On the way from the X-point to the magnetic islands, particles turn in the magnetic field, forming a fan confined to the current sheet. Once they reach the islands they isotropise after completing a full Larmor gyration and their radiation is not strongly beamed anymore. The radiation pattern at a given freq...

  15. 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...

  16. 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...

  17. Particle beam fusion progress report for 1989

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, M.A. [ed.] [Sandia National Labs., Albuquerque, NM (United States). Pulsed Power Sciences Center

    1994-08-01

    This report summarizes the progress on the pulsed power approach to inertial confinement fusion. In 1989, the authors achieved a proton focal intensity of 5 TW/cm{sup 2} on PBFA-II in a 15-cm-radius applied magnetic-field (applied-B) ion diode. This is an improvement by a factor of 4 compared to previous PBFA-II experiments. They completed development of the three-dimensional (3-D), electromagnetic, particle-in-cell code QUICKSILVER and obtained the first 3-D simulations of an applied-B ion diode. The simulations, together with analytic theory, suggest that control of electromagnetic instabilities could reduce ion divergence. In experiments using a lithium fluoride source, they delivered 26 kJ of lithium energy to the diode axis. Rutherford-scattered ion diagnostics have been developed and tested using a conical foil located inside the diode. They can now obtain energy density profiles by using range filters and recording ion images on nuclear track recording film. Timing uncertainties in power flow experiments on PBFA-II have been reduced by a factor of 5. They are investigating three plasma opening switches that use magnetic fields to control and confine the injected plasma. These new switches provide better power flow than the standard plasma erosion switch. Advanced pulsed-power fusion drivers will require extraction-geometry applied-B ion diodes. During this reporting period, progress was made in evaluating the generation, transport, and focus of multiple ion beams in an extraction geometry and in assessing the probable damage to a target chamber first wall.

  18. Particle beam fusion progress report for 1989

    International Nuclear Information System (INIS)

    This report summarizes the progress on the pulsed power approach to inertial confinement fusion. In 1989, the authors achieved a proton focal intensity of 5 TW/cm2 on PBFA-II in a 15-cm-radius applied magnetic-field (applied-B) ion diode. This is an improvement by a factor of 4 compared to previous PBFA-II experiments. They completed development of the three-dimensional (3-D), electromagnetic, particle-in-cell code QUICKSILVER and obtained the first 3-D simulations of an applied-B ion diode. The simulations, together with analytic theory, suggest that control of electromagnetic instabilities could reduce ion divergence. In experiments using a lithium fluoride source, they delivered 26 kJ of lithium energy to the diode axis. Rutherford-scattered ion diagnostics have been developed and tested using a conical foil located inside the diode. They can now obtain energy density profiles by using range filters and recording ion images on nuclear track recording film. Timing uncertainties in power flow experiments on PBFA-II have been reduced by a factor of 5. They are investigating three plasma opening switches that use magnetic fields to control and confine the injected plasma. These new switches provide better power flow than the standard plasma erosion switch. Advanced pulsed-power fusion drivers will require extraction-geometry applied-B ion diodes. During this reporting period, progress was made in evaluating the generation, transport, and focus of multiple ion beams in an extraction geometry and in assessing the probable damage to a target chamber first wall

  19. Blowup and specialization methods for the study of linear systems

    Directory of Open Access Journals (Sweden)

    Joaquim Roe

    2012-04-01

    Full Text Available The computation of the dimension of linear systems of curves with imposed base multiple points on surfaces is a difficult problem, with open conjectures that are being approached only with partial success. Among others, blowup-based techniques and degenerations show some promise of leading to satisfactory answers. We present an overview of such blowup based techniques at an introductory level, with emphasis on clusters of infinitely near points and Ciliberto-Miranda's blowup and twist.

  20. Particle beam radiation therapy:re-introducing the future

    Institute of Scientific and Technical Information of China (English)

    Omar Abdel-Rahman

    2014-01-01

    Particle radiation therapy is an exciting area of radiotherapy basic and clinical researches. The majority of particle radiotherapy work is being done with proton beams having essential y the same radiobiologic properties as conventional photon/electron radiation but al owing a much more precise control of the radiation dose distribution. However, other charged particles are also playing an increasing role, like neutrons. In this review article we wil summarize the data related to basic and clinical experiences related to particle beam radiation therapy.

  1. Charged particle beam scanning using deformed high gradient insulator

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu -Jiuan

    2015-10-06

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

  2. Charged particle beam scanning using deformed high gradient insulator

    Science.gov (United States)

    Chen, Yu -Jiuan

    2015-10-06

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

  3. Cryogenic Beam Screens for High-Energy Particle Accelerators

    CERN Document Server

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

    2013-01-01

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

  4. Blow-up Sets to a Coupled Heat System

    Institute of Scientific and Technical Information of China (English)

    Wang Jin-huan; Hong Liang

    2014-01-01

    This paper deals with a heat system coupled via local and localized sources subject to null Dirichlet boundary conditions. In a previous paper of the authors, a complete result on the multiple blow-up rates was obtained. In the present paper, we continue to consider the blow-up sets to the system via a complete classification for the nonlinear parameters. That is the discussion on single point versus total blow-up of the solutions. It is mentioned that due to the influence of the localized sources, there is some substantial difficulty to be overcomed there to deal with the single point blow-up of the solutions.

  5. Beaming of Particles and Synchrotron Radiation in Relativistic Magnetic Reconnection

    Science.gov (United States)

    Kagan, Daniel; Nakar, Ehud; Piran, Tsvi

    2016-08-01

    Relativistic reconnection has been invoked as a mechanism for particle acceleration in numerous astrophysical systems. According to idealized analytical models, reconnection produces a bulk relativistic outflow emerging from the reconnection sites (X-points). The resulting radiation is therefore highly beamed. Using two-dimensional particle-in-cell simulations, we investigate particle and radiation beaming, finding a very different picture. Instead of having a relativistic average bulk motion with an isotropic electron velocity distribution in its rest frame, we find that the bulk motion of the particles in X-points is similar to their Lorentz factor γ, and the particles are beamed within ˜ 5/γ . On the way from the X-point to the magnetic islands, particles turn in the magnetic field, forming a fan confined to the current sheet. Once they reach the islands they isotropize after completing a full Larmor gyration and their radiation is no longer strongly beamed. The radiation pattern at a given frequency depends on where the corresponding emitting electrons radiate their energy. Lower-energy particles that cool slowly spend most of their time in the islands and their radiation is not highly beamed. Only particles that quickly cool at the edge of the X-points generate a highly beamed fan-like radiation pattern. The radiation emerging from these fast cooling particles is above the burn-off limit (˜100 MeV in the overall rest frame of the reconnecting plasma). This has significant implications for models of gamma-ray bursts and active galactic nuclei that invoke beaming in that frame at much lower energies.

  6. Simultaneous and non-simultaneous blow-up and uniform blow-up profiles for reaction-diffusion system

    Directory of Open Access Journals (Sweden)

    Zhengqiu Ling

    2012-11-01

    Full Text Available This article concerns the blow-up solutions of a reaction-diffusion system with nonlocal sources, subject to the homogeneous Dirichlet boundary conditions. The criteria used to identify simultaneous and non-simultaneous blow-up of solutions by using the parameters p and q in the model are proposed. Also, the uniform blow-up profiles in the interior domain are established.

  7. Compact heterotic orbifolds in blow-up

    CERN Document Server

    Nibbelink, Stefan Groot; Plöger, Felix; Trapletti, Michele; Vaudrevange, Patrick K S

    2008-01-01

    We compare heterotic string models on orbifolds with supergravity models on smooth compact spaces, obtained by resolving the orbifold singularities. Our main focus is on heterotic E8xE8 models on the resolution of the compact T^6/Z_3 orbifold with Wilson lines. We explain how different gauge fluxes at various resolved fixed points can be interpreted in blow down as Wilson lines. Even when such Wilson lines are trivial from the orbifold perspective, they can still lead to additional symmetry breaking in blow-up. Full agreement is achieved between orbifold and resolved models, at the level of gauge interactions, massless spectrum and anomaly cancellation. In this matching the blow-up modes are of crucial importance: they play the role of model-dependent axions involved in the cancellation of multiple anomalous U(1)'s on the resolution. We illustrate various aspects by investigating blow-ups of a Z_3 MSSM model with two Wilson lines: if all its fixed points are resolved simultaneously, the SM gauge group is nece...

  8. Blow-up in nonlinear Schroedinger equations. II. Similarity structure of the blow-up singularity

    DEFF Research Database (Denmark)

    Rypdal, K.; Juul Rasmussen, Jens

    1986-01-01

    A critical review of the literature on similarity solutions of nonlinear Schroedinger equations is presented. We demonstrate that the self-similar blow-up solutions discovered hitherto are all associated either with a simple stretching invariance, or with a slightly more complicated conformal...... invariance and generalizations of the latter. This generalized "quasi-invariance" reveals the nature of the blow-up singularity and resolves an old controversy. Most of the previous work has been done on the cubic nonlinearity. We generalize the results to an arbitrary power nonlinearity....

  9. Particle reflection and TFTR neutral beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O`Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1992-04-01

    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12{degrees}). Beamline calorimeters, of a ``V``-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the ``V``, complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.

  10. Particle reflection and TFTR neutral beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O' Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1992-04-01

    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12{degrees}). Beamline calorimeters, of a V''-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the V'', complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.

  11. Beams '96. Proceedings of the 11th international conference on high power particle beams. Vol. II

    International Nuclear Information System (INIS)

    The scientific programme of the conference carved the physics and technology of intense beams of charged particles, from basic experimental and theoretical problems of beam generation, transport and interaction with various media, up to beam and pulsed power applications in science and in industry. The breakdown of the papers by main topical groups is as follows: radiation sources, Z-pinches, accelerate related topics, astrophysics, ICF, ION Beam Physics, ION DIODES, ION RINGS, Beam plasma systems, diagnostic and others. This volumes contains 160 contributions, out which 133 have been input to INIS

  12. Control of Beam Halo-Chaos Based on Self-Field-Intensity of Particle Beam

    Institute of Scientific and Technical Information of China (English)

    YU Hai-Jun; BAI Long; WENG Jia-Qiang; LUO Xiao-Shu

    2008-01-01

    @@ The KV beam through an axisymmetric periodic-focusing magnetic field is studied using the particle-core model.A new variable of the self-field-intensity of particle beam is selected,and an idea of self-field feedback controller is proposed based on the variable for controlling the halo-chaos.We perform multiparticle simulation to control the halo by using the self-field feedback controller.

  13. Laser-driven beam lines for delivering intensity modulated radiation therapy with particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, K. M.; Schell, S.; Wilkens, J. J. [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München (Germany)

    2013-07-26

    Laser-accelerated particles can provide a promising opportunity for radiation therapy of cancer. Potential advantages arise from combining a compact, cost-efficient treatment unit with the physical advantages in dose delivery of charged particle beams. We consider different dose delivery schemes and the required devices to design a possible treatment unit. The secondary radiation produced in several beam line elements remains a challenge to be addressed.

  14. Cherenkov counter for particle identification test beam

    International Nuclear Information System (INIS)

    The Cherenkov counter used for selecting electrons of the test beam has been studied in this article. The design, manufacture, assembly and testing of the Cherenkov counter are described. And the performance of this counter is measured. The CO2 gas is used as Cherenkov radiator, the XP2020Q photomultiplier is applied for recording signals of the Cherenkov light. The (99.0±0.5)% efficiency of the electron selection has been reached

  15. Exact Blow-up Solutions for Multidimensional Landau--LifshitzEquations

    Institute of Scientific and Technical Information of China (English)

    郭柏灵; 韩永前; 杨干山

    2001-01-01

    @@  We present exact blow-up solutions for multidimensionalLandau--Lifshitz equations. It is shown that for any prescribed blow-up timethere are exact C∞--solutions which are blow-up at the blow-up timeand that the solutions are smooth except at theblow-up time.

  16. TOTAL VERSUS SINGLE POINT BLOW-UP SOLUTIONS FOR A SEMILINEAR PARABOLIC EQUATION

    Institute of Scientific and Technical Information of China (English)

    Yang Ming

    2007-01-01

    In this paper, we investigate the blow-up set of solutions of a parabolic equation with localized and non-localized reactions. We completely classify blow-up solutions into total blow-up cases and single point blow-up cases.

  17. Dust particle diffusion in ion beam transport region

    Science.gov (United States)

    Miyamoto, N.; Okajima, Y.; Romero, C. F.; Kuwata, Y.; Kasuya, T.; Wada, M.

    2016-02-01

    Dust particles of μm size produced by a monoplasmatron ion source are observed by a laser light scattering. The scattered light signal from an incident laser at 532 nm wavelength indicates when and where a particle passes through the ion beam transport region. As the result, dusts with the size more than 10 μm are found to be distributed in the center of the ion beam, while dusts with the size less than 10 μm size are distributed along the edge of the ion beam. Floating potential and electron temperature at beam transport region are measured by an electrostatic probe. This observation can be explained by a charge up model of the dust in the plasma boundary region.

  18. CAS course on Intensity Limitations in Particle Beams at CERN

    CERN Multimedia

    CERN Accelerator School

    2015-01-01

    The CERN Accelerator School (CAS) recently organised a specialised course on Intensity Limitations in Particle Beams, at CERN from 2 to 11 November, 2015.     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. This course covered the interaction of beams with their surroundings and with other beams, as well as further collective effects. The lectures on the effects and possible mitigations were complemented by tutorials. The course was very successful, with 66 students representing 14 nationalities attending. Most participants came from European counties, but also from Armenia, China and Russia. Feedback from the participants was positive, reflecting the standard of the lectures and teaching. In addition to the academic pro...

  19. Electro-Optical Detection of Charged Particle Beams

    CERN Document Server

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

    1999-01-01

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

  20. Literature in focus: Particle beams from theory to practice

    CERN Multimedia

    2003-01-01

    Wednesday 1st October 16 h00 - Central Library CERN's Frank Zimmermann and DESY's Michiko G. Minty had their book 'Measurement and control of charged particle beams' published a few months ago by Springer. Frank Zimmermann, a young but already well established accelerator physicist, was awarded the European Accelerator Prize by the Interdivisional Group on Accelerators of the European Physical Society last year. Mr. Zimmermann was particularly cited for his significant contribution to the understanding of fast ion and electron cloud instabilities. The book is the first comprehensive and systematic review of all methods used for the measurement, correction, and control of the beam dynamics of modern particle accelerators and is intended for graduate students starting research or work in the field of beam physics. Specific techniques and methods for relativistic beams are illustrated by examples from operational accelerators, like CERN, DESY, SLAC, KEK, LBNL, and FNAL. Problems and solutions enhance the book...

  1. Dust particle diffusion in ion beam transport region

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, N.; Okajima, Y.; Romero, C. F.; Kuwata, Y.; Kasuya, T.; Wada, M., E-mail: mwada@mail.doshisha.ac.jp [Graduate school of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2016-02-15

    Dust particles of μm size produced by a monoplasmatron ion source are observed by a laser light scattering. The scattered light signal from an incident laser at 532 nm wavelength indicates when and where a particle passes through the ion beam transport region. As the result, dusts with the size more than 10 μm are found to be distributed in the center of the ion beam, while dusts with the size less than 10 μm size are distributed along the edge of the ion beam. Floating potential and electron temperature at beam transport region are measured by an electrostatic probe. This observation can be explained by a charge up model of the dust in the plasma boundary region.

  2. Beams '96. Proceedings of the 11th international conference on high power particle beams. Vol. I

    International Nuclear Information System (INIS)

    The Proceedings contain the full texts of 60 orals and 243 poster papers presented at the Conference. The scientific programme of the conference covered the physics and technology of intense beams of charged particles, from basic experimental and theoretical problems of beam generation, transport and interaction with various media, up to beam and pulsed power applications in science and in industry. The breakdown of the papers by main topical groups is as follows: electron beams, beam-plasma systems, high-power microwaves (62), imploding liners, z-pinches, plasma foci (53), pulsed power technology and its applications (53), ion beams and ICF (41), industrial applications of electron and ion beams (36), radiation sources (23), diagnostics (14), and others (21). (J.U.)

  3. Interactive visualization of particle beams for accelerator design

    International Nuclear Information System (INIS)

    We describe a hybrid data-representation and rendering technique for visualizing large-scale particle data generated from numerical modeling of beam dynamics. The basis of the technique is mixing volume rendering and point rendering according to particle density distribution, visibility, and the user's instruction. A hierarchical representation of the data is created on a parallel computer, allowing real-time partitioning into high-density areas for volume rendering, and low-density areas for point rendering. This allows the beam to be interactively visualized while preserving the fine structure usually visible only with slow point based rendering techniques

  4. Multiparametric ionization probes for monitoring accelerated particle beams

    International Nuclear Information System (INIS)

    Paper describes high-sensitive ionization probes of transverse cross section of accelerated particle beam. Image of beam real cross section is formed at the display of electron-optical converter on the basis of multichannel plates, is recorded by TV camera and is processes and presented by means of computer. Probe structures for 1-100 MeV energy round and strip beams are developed and tested. Distortions of beam cross section image under the effect of the external magnetic field and of space charge field are estimated. The results of the first investigations into prototype ionization probes to control form, duration, phase of cyclotron beam microclusters are presented. 13 refs.; 9 figs

  5. Particle beams carrying orbital angular momentum, charge, mass and spin

    Science.gov (United States)

    Tijssen, Teuntje; Hayrapetyan, Armen; Goette, Joerg; Dennis, Mark

    Electron beams carrying vortices and angular momentum have been of much experimental and theoretical interest in recent years. In addition, optical vortex beams are a well-established field in optics and photonics. In both cases, the orbital angular momentum associated with the beam's axial vortex has effects on the overall spin of the beam, due to spin-orbit interactions. A simple model of these systems are Bessel beam solutions (of either the Dirac equation or Maxwell equations) with a nonzero azimuthal quantum number, which are found by separation in cylindrical coordinates. Here, we generalize this approach, considering the classical field theory of Bessel beams for particles which are either massive or massless, uncharged or charged and of a variety of different spins (0, 1/2, 1, ⋯). We regard the spin and helicity states and different forms of spin-orbit terms that arise. Moreover, we analyse the induced electromagnetic field when the particles carry charge. Most importantly, this unified field theory approach leads to the prediction of effects for vortex beams of neutrons, mesons and neutrinos.

  6. Dynamics of fast charged particle beam rotation in bended crystals

    International Nuclear Information System (INIS)

    Dynamics of fast charged particle beam rotation in a bended monocrystal is considered. Face and volume mechanisms of capture in channels are taken into account simultaneously in the model presented. Functions of distribution in transverse energies (φ) of channeled and dechanneled particles are obtained. Charge-energy ''scale invariance'' in ion channeling with charge Z in a bended crystal determined by scale parameter W=pv/Z (p and v are pulse and velocity local to transverse planes) follows from the model presented

  7. 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 ...

  8. Optimizing Stellarators for Energetic Particle Confinement using BEAMS3D

    Science.gov (United States)

    Bolgert, Peter; Drevlak, Michael; Lazerson, Sam; Gates, David; White, Roscoe

    2015-11-01

    Energetic particle (EP) loss has been called the ``Achilles heel of stellarators,'' (Helander, Rep. Prog. Phys. 77 087001 (2014)) and there is a great need for magnetic configurations with improved EP confinement. In this study we utilize a newly developed capability of the stellarator optimization code STELLOPT: the ability to optimize EP confinement via an interface with guiding center code BEAMS3D (McMillan et al., Plasma Phys. Control. Fusion 56, 095019 (2014)). Using this new tool, optimizations of the W7-X experiment and ARIES-CS reactor are performed where the EP loss fraction is one of many target functions to be minimized. In W7-X, we simulate the experimental NBI system using realistic beam geometry and beam deposition physics. The goal is to find configurations with improved neutral beam deposition and energetic particle confinement. These calculations are compared to previous studies of W7-X NBI deposition. In ARIES-CS, we launch 3.5 MeV alpha particles from a near-axis flux surface using a uniform grid in toroidal and poloidal angle. As these particles are born from D-T reactions, we consider an isotropic distribution in velocity space. This research is supported by DoE Contract Number DE-AC02-09CH11466.

  9. Beam-size or MD-effect at colliders and correlations of particles in a beam

    CERN Document Server

    Kotkin, G L

    2003-01-01

    For several processes at colliding beams, macroscopically large impact parameters give an essential contribution to the standard cross section. These impact parameters may be much larger than the transverse sizes of the colliding bunches. In that case, the standard calculations have to be essentially modify. The corresponding formulae for such a beam-size effect were given twenty years ago without taking into account correlations of particle coordinates in the beams. In the present paper we derive formulae which necessary to take into account quantitatively the effect of particle correlations in the spectrum of bremsstrahlung as well as in pair production. Besides, we consider critically recent papers of Baier and Katkov [Phys. Rev. D {\\bf 66}, 053009 (2002) and hep-ph/0305304] in which it was calculated a new additional ``subtraction term'' related to the coherent contribution into beam-size effect. We show that this result is groundless and point out the origin of the mistake.

  10. Technical review of the Sandia Laboratories' Particle Beam Fusion Program

    International Nuclear Information System (INIS)

    This report considers the technical aspects of Sandia Laboratories' Particle Beam Fusion Program and examines the program's initial goals, the progress made to date towards reaching those goals, and the future plans or methods of reaching those original or modified goals. A summary of Sandia Laboratories' effort, which seeks to demonstrate that high voltage pulsed power generated high-current electron or light ion beams can be used to ignite a deuterium or tritium pellet, is provided. A brief review and assessment of the Sandia Pulse Power Program is given. Several critical issues and summaries of the committee members' opinions are discussed

  11. Nonlinear Stability Theorem for High-Intensity Charged Particle Beams

    International Nuclear Information System (INIS)

    Global conservation constraints based on the nonlinear Vlasov-Maxwell equations are used to derive a three-dimensional kinetic stability theorem for an intense non-neutral ion beam (or charge bunch) propagating with average axial velocity vb=const . It is shown that a sufficient condition for linear and nonlinear stability for perturbations with arbitrary polarization is that the equilibrium distribution be a monotonically decreasing function of the single-particle energy H' in the beam frame, i.e., ∂feq(H') /∂H'≤0 . copyright 1998 The American Physical Society

  12. Blowup for degenerate and singular parabolic system with nonlocal source

    Directory of Open Access Journals (Sweden)

    Zhou Jun

    2006-01-01

    Full Text Available We deal with the blowup properties of the solution to the degenerate and singular parabolic system with nonlocal source and homogeneous Dirichlet boundary conditions. The existence of a unique classical nonnegative solution is established and the sufficient conditions for the solution that exists globally or blows up in finite time are obtained. Furthermore, under certain conditions it is proved that the blowup set of the solution is the whole domain.

  13. 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

  14. Particle Beam Therapy for Cancer of the Skull Base, Nasal Cavity, and Paranasal Sinus

    OpenAIRE

    Fukumitsu, Nobuyoshi

    2012-01-01

    Particle beam therapy has been rapidly developed in these several decades. Proton and carbon ion beams are most frequently used in particle beam therapy. Proton and carbon ion beam radiotherapy have physical and biological advantage to the conventional photon radiotherapy. Cancers of the skull base, nasal cavity, and paranasal sinus are rare; however these diseases can receive the benefits of particle beam radiotherapy. This paper describes the clinical review of the cancer of the skull base,...

  15. MeV ion beam deformation of colloidal silica particles

    International Nuclear Information System (INIS)

    Spherical sub-micrometer-sized silica particles were prepared by the Stoeber process, from a reaction mixture containing tetraethoxysilane, ammonia and ethanol, and deposited into silicon wafers. The samples were then irradiated at room temperature with 4 MeV Si, Ti, Pt or Au ions at a fluence of 4 x 1015 ions/cm2, under an angle of 49o with respect to the sample surface. The size, size distribution and shape of the silica particles were determined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). After the irradiation the spherical silica particles can be turned into ellipsoidal particles, as a result of the increase of the particle dimension perpendicular to the ion beam and a decrease in the direction parallel to the ion beam. This effect increases with the ion fluence and depends on the electronic stopping power of the impinging ion. For the series of 4 MeV ions we used in this work a relative transverse diameter change of 17% per 1 keV/nm was obtained and it seems that no threshold for the electronic energy loss exists

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

    International Nuclear Information System (INIS)

    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 (1012 W/cm2) prior to the main pulse (∝ns), an optimum pre-plasma density scale length of 60 μm is generated leading to an enhancement of the maximum proton energy (∝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 μm foil irradiated with an intensity of 1019 W/cm2 onto a 60 μm 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 plasma physics group of the Technische Universitat Darmstadt

  17. 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

  18. Method and system for treating an interior surface of a workpiece using a charged particle beam

    Science.gov (United States)

    Swenson, David Richard

    2007-05-23

    A method and system of treating an interior surface on an internal cavity of a workpiece using a charged particle beam. A beam deflector surface of a beam deflector is placed within the internal cavity of the workpiece and is used to redirect the charged particle beam toward the interior surface to treat the interior surface.

  19. Carbon dust particles in a beam-plasma discharge

    Science.gov (United States)

    Koval, O. A.; Vizgalov, V.; Shalpegin, A. V.

    2016-09-01

    This paper focuses on dynamics of micro-sized carbon dust grains in beam-plasma discharge (BPD) plasmas. It was demonstrated that injected dust particles can be captured and transported along the discharge. Longitudinal average velocity of the particles in the central area of the plasma column was 17 m/sec, and 2 m/sec in the periphery. Dust injection caused a decrease of emission intensity of metastable nitrogen molecular ion. This effect is suggested for a spectroscopy method for particles’ potential measurements. Five-micron radius carbon dust grains obtained potential above 500 V in the experiments on PR-2 installation, proving the feasibility of BPDs for the charging of fine dust particles up to high potential values, unattainable in similar plasma conditions.

  20. Blow-up estimates for semilinear parabolic systems coupled in an equation and a boundary condition

    Institute of Scientific and Technical Information of China (English)

    王明新

    2001-01-01

    This paper deals with the blow-up rate estimates of solutions for semilinear parabolic systems coupled in an equation and a boundary condition. The upper and lower bounds of blow-up rates have been obtained.

  1. On the Blow-up Phenomena of Cauchy Problem for the Camassa- Holm Equation

    Institute of Scientific and Technical Information of China (English)

    LIU Yongqin; WANG Weike

    2006-01-01

    We focus on the blow-up phenomena of Cauchy problem for the Camassa-Holm equation. Blow-up can occur only in the form of wave-breaking, i.e. the solution is bounded but its slope becomes unbounded in finite time. We proved that there is such a point that its slope becomes infinite exactly at breaking time. We also gave the precise blow-up rate and the blow-up set.

  2. Charged-particle beam diagnostics for the advanced photon source

    Science.gov (United States)

    Lumpkin, A. H.; Decker, G.; Kahana, E.; Patterson, D.; Sellyey, W.; Wang, X.; Chung, Y.

    1993-07-01

    Plans, prototypes, and initial test results for the charged-particle beam (e -, e +) diagnostic systems on the injector rings, their transport lines, and the storage ring for the Advanced Photon Source (APS) are presented. The APS will be a synchrotron radiation user facility with one of the world's brightest X-ray sources in the 10-keV regime. Its 200-MeV electron linac, 450-MeV positron linac, positron accumulator ring, 7-GeV injector synchrotron (IS), 7-GeV storage ring (SR), and undulator test lines will also demand the development and demonstration of key particle-beam characterization techniques over a wide range of parameter space. Some of these parameter values overlap or approach those projected for fourth generation light sources (linac-driven FELs and high brightness storage rings) as described at a recent workshop. Initial results from the diagnostics prototypes on the linac test stand operating at 45-MeV include current monitor data, beam loss monitor data, and video digitization using VME architecture.

  3. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.;

    atmospheric conditions using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear and significant contribution from ion induced nucleation and consider this to be an unambiguous observation of the ion-effect on aerosol nucleation using a particle beam under conditions not far......The effect of ions in aerosol nucleation is a subject where much remains to be discovered. That ions can enhance nucleation has been shown by theory, observations, and experiments. However, the exact mechanism still remains to be determined. One question is if the nature of the ionization affects...... the nucleation. This is an essential question since many experiments have been performed using radioactive sources that ionize differently than the cosmic rays which are responsible for the majority of atmospheric ionization. Here we report on an experimental study of sulphuric acid aerosol nucleation under near...

  4. BOA, Beam Optics Analyzer A Particle-In-Cell Code

    Energy Technology Data Exchange (ETDEWEB)

    Thuc Bui

    2007-12-06

    The program was tasked with implementing time dependent analysis of charges particles into an existing finite element code with adaptive meshing, called Beam Optics Analyzer (BOA). BOA was initially funded by a DOE Phase II program to use the finite element method with adaptive meshing to track particles in unstructured meshes. It uses modern programming techniques, state-of-the-art data structures, so that new methods, features and capabilities are easily added and maintained. This Phase II program was funded to implement plasma simulations in BOA and extend its capabilities to model thermal electrons, secondary emissions, self magnetic field and implement a more comprehensive post-processing and feature-rich GUI. The program was successful in implementing thermal electrons, secondary emissions, and self magnetic field calculations. The BOA GUI was also upgraded significantly, and CCR is receiving interest from the microwave tube and semiconductor equipment industry for the code. Implementation of PIC analysis was partially successful. Computational resource requirements for modeling more than 2000 particles begin to exceed the capability of most readily available computers. Modern plasma analysis typically requires modeling of approximately 2 million particles or more. The problem is that tracking many particles in an unstructured mesh that is adapting becomes inefficient. In particular memory requirements become excessive. This probably makes particle tracking in unstructured meshes currently unfeasible with commonly available computer resources. Consequently, Calabazas Creek Research, Inc. is exploring hybrid codes where the electromagnetic fields are solved on the unstructured, adaptive mesh while particles are tracked on a fixed mesh. Efficient interpolation routines should be able to transfer information between nodes of the two meshes. If successfully developed, this could provide high accuracy and reasonable computational efficiency.

  5. 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...

  6. Vertical coherent instabilities in bunched particle-beams

    International Nuclear Information System (INIS)

    The purpose of this paper is to study the vertical coherent instabilities which occur in bunched particle beams. The problem is complicated by the fact that the velocity of a single particle in a bunch is not constant, but rather consists of an equilibrium velocity and an oscillation about that. This synchrotron oscillation occurs at a frequency which is in general much less than the other characteristic frequencies of the system: the revolution frequency and the transverse betatron frequencies. The approach used here to study coherent instabilities illuminates the effect of the synchrotron frequency in setting the time scale for an instability, without making restrictive assumptions on the relative size of the synchrotron frequency and the coherent frequency shift

  7. Beam optics and lattice design for particle accelerators

    CERN Document Server

    Holzer, Bernhard J

    2013-01-01

    The goal of this manuscript is to give an introduction into the design of the magnet lattice and as a consequence into the transverse dynamics of the particles in a synchrotron or storage ring. Starting from the basic principles of how to design the geometry of the ring we will briefly review the transverse motion of the particles and apply this knowledge to study the layout and optimization of the principal elements, namely the lattice cells. The detailed arrangement of the accelerator magnets within the cells is explained and will be used to calculate well defined and predictable beam parameters. The more specific treatment of low beta insertions is included as well as the concept of dispersion suppressors that are an indispensable part of modern collider rings.

  8. 3D Simulations of Space Charge Effects in Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Adelmann, A

    2002-10-01

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

  9. Enhanced creation of high energy particles in colliding laser beams

    CERN Document Server

    Kuchiev, Michael

    2015-01-01

    The creation of particles by two colliding strong laser beams is considered. It is found that the electron-positron pairs created in the laser field via the Schwinger mechanism may recollide after one or several oscillations in the field. Their collision can take place at high energy, which the pair gains from the field. As a result, high energy gamma quanta can be created by inelastic scattering or annihilation of the pair. Moreover, heavy particles such as muon pairs may also be created via the annihilation $e^+ + e^-\\rightarrow \\mu^+ + \\mu^- $. The probability of $e^-e^+$ collision is greatly enhanced due to a strong alignment of the electron and positron momenta with the electric field. The found muon creation rate exponentially exceeds the rate predicted by the direct Schwinger mechanism for muons, while the photon creation rate exponentially exceeds photon emission due to the fermion oscillation.

  10. Single beam two-views holographic particle image velocimetry.

    Science.gov (United States)

    Sheng, Jian; Malkiel, Edwin; Katz, Joseph

    2003-01-10

    Holographic particle image velocimetry (HPIV) is presently the only method that can measure at high resolution all three components of the velocity in a finite volume. In systems that are based on recording one hologram, velocity components parallel to the hologram can be measured throughout the sample volume, but elongation of the particle traces in the depth direction severely limits the accuracy of the velocity component that is perpendicular to the hologram. Previous studies overcame this limitation by simultaneously recording two orthogonal holograms, which inherently required four windows and two recording systems. This paper introduces a technique that maintains the advantages of recording two orthogonal views, but requires only one window and one recording system. Furthermore, it enables a quadruple increase in the spatial resolution. This method is based on placing a mirror in the test section that reflects the object beam at an angle of 45 degrees. Particles located in the volume in which the incident and reflected beams from the mirror overlap are illuminated twice in perpendicular directions. Both views are recorded on the same hologram. Off-axis holography with conjugate reconstruction and high-pass filtering is used for recording and analyzing the holograms. Calibration tests show that two views reduce the uncertainty in the three-dimensional (3-D) coordinates of the particle centroids to within a few microns. The velocity is still determined plane-by-plane by use of two-dimensional particle image velocimetry procedures, but the images are filtered to trim the elongated traces based on the 3-D location of the particle. Consequently, the spatial resolution is quadrupled. Sample data containing more than 200 particles/mm3 are used for calculating the 3-D velocity distributions with interrogation volumes of 220 x 154 x 250 microm, and vector spacing of 110 x 77 x 250 microm. Uncertainty in velocity is addressed by examining how well the data satisfies

  11. Finite Time Blowup in a Realistic Food-Chain Model

    KAUST Repository

    Parshad, Rana D.

    2013-05-19

    We investigate a realistic three-species food-chain model, with generalist top predator. The model based on a modified version of the Leslie-Gower scheme incorporates mutual interference in all the three populations and generalizes several other known models in the ecological literature. We show that the model exhibits finite time blowup in certain parameter range and for large enough initial data. This result implies that finite time blowup is possible in a large class of such three-species food-chain models. We propose a modification to the model and prove that the modified model has globally existing classical solutions, as well as a global attractor. We reconstruct the attractor using nonlinear time series analysis and show that it pssesses rich dynamics, including chaos in certain parameter regime, whilst avoiding blowup in any parameter regime. We also provide estimates on its fractal dimension as well as provide numerical simulations to visualise the spatiotemporal chaos.

  12. Blow-up of Solutions to Porous Medium Equations with a Nonlocal Boundary Condition and a Moving Localized Source

    Institute of Scientific and Technical Information of China (English)

    SUN PENG; GAO WEN-JIE; HAN YU-ZHU

    2012-01-01

    This paper is devoted to the blow-up properties of solutions to the porous medium equations with a nonlocal boundary condition and a moving localized source.Conditions for the existence of global or blow-up solutions are obtained.Moreover,we prove that the unique solution has global blow-up property whenever blow-up Occurs.

  13. Particle-beam-fusion progress report, July 1979 through December 1979

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The following chapters are included in this semi-annual progress report: (1) fusion target studies, (2) target experiments, (3) particle-beam source developments, (4) particle beam experiments, (5) pulsed power, (6) pulsed power applications, and (7) electron beam fusion accelerator project. (MOW)

  14. Particle-beam-fusion progress report, July 1979 through December 1979

    International Nuclear Information System (INIS)

    The following chapters are included in this semi-annual progress report: (1) fusion target studies, (2) target experiments, (3) particle-beam source developments, (4) particle beam experiments, (5) pulsed power, (6) pulsed power applications, and (7) electron beam fusion accelerator project

  15. 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.

  16. Automatic beam path analysis of laser wakefield particle acceleration data

    Energy Technology Data Exchange (ETDEWEB)

    Ruebel, Oliver; Wu, Kesheng; Prabhat; Weber, Gunther H; Ushizima, Daniela M; Hamann, Bernd; Bethel, Wes [Computational Research Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Geddes, Cameron G R; Cormier-Michel, Estelle [LOASIS program of Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Messmer, Peter [Tech-X Corporation, 5621 Arapahoe Avenue Suite A, Boulder, CO 80303 (United States); Hagen, Hans [International Research Training Group ' Visualization of Large and Unstructured Data Sets-Applications in Geospatial Planning, Modeling, and Engineering' , Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse, D-67653 Kaiserslautern (Germany)], E-mail: oruebel@lbl.gov

    2009-01-01

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

  17. Particle beam fusion. Progress report, April 1978-December 1978

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    During this period substantial improvements in the theoretical basis for particle beam fusion as well as the execution of critical experiments were instrumental in further definition of the optimum route to our goals of demonstrating scientific and practical feasibility. The major emphasis in the program continues to be focused primarily on issues of power concentration and energy deposition of intense particle beams in solid targets. This utilization of program resources is directed toward conducting significant target implosion and thermonuclear burn experiments using EBFA-I (1 MJ) in the 1981-1983 time period. This step, using EBFA-I, will then set the stage for net energy gain experiments to follow on EBFA-II (> 2 MJ) after 1985. Current program emphasis and activities differ substantially from those stressed in the laser approaches to inertial confinement fusion. Here the critical issues relate to delivering the needed power densities and energies to appropriate targets and to insure that the coupling of energy is efficient and matches target requirements.

  18. Particle beam fusion. Progress report, April 1978-December 1978

    International Nuclear Information System (INIS)

    During this period substantial improvements in the theoretical basis for particle beam fusion as well as the execution of critical experiments were instrumental in further definition of the optimum route to our goals of demonstrating scientific and practical feasibility. The major emphasis in the program continues to be focused primarily on issues of power concentration and energy deposition of intense particle beams in solid targets. This utilization of program resources is directed toward conducting significant target implosion and thermonuclear burn experiments using EBFA-I (1 MJ) in the 1981-1983 time period. This step, using EBFA-I, will then set the stage for net energy gain experiments to follow on EBFA-II (> 2 MJ) after 1985. Current program emphasis and activities differ substantially from those stressed in the laser approaches to inertial confinement fusion. Here the critical issues relate to delivering the needed power densities and energies to appropriate targets and to insure that the coupling of energy is efficient and matches target requirements

  19. Blow-up in nonlinear Sobolev type equations

    CERN Document Server

    Al'shin, Alexander B; Sveshnikov, Alexey G

    2011-01-01

    The monograph is devoted to the study of initial-boundary-value problems for multi-dimensional Sobolev-type equations over bounded domains. The authors consider both specific initial-boundary-value problems and abstract Cauchy problems for first-order (in the time variable) differential equations with nonlinear operator coefficients with respect to spatial variables. The main aim of the monograph is to obtain sufficient conditions for global (in time) solvability, to obtain sufficient conditions for blow-up of solutions at finite time, and to derive upper and lower estimates for the blow-up ti

  20. Avoidance of Blow-up by Moving Medium

    Institute of Scientific and Technical Information of China (English)

    YAOLi; LIUYun-xian; YANGPeng-fei

    2005-01-01

    This paper deals with two parabolic inltial-boundary value problems in multidimensional domain. The first problem describes the situation where the spherical medium is static and the nonlinear reaction takes place only at a single point. We show that under some conditions, the solution blows up in finite time and the blow-up set is the whole spherical medium. When the spherical medium is allowed to move in a special space, we investigate another parabolic initial-boundary value problem. It is proved that the blow-up can be avoided if the acceleration of the motion satisfies certain conditions.

  1. Periodicity and blowup in a two-species cooperating model

    DEFF Research Database (Denmark)

    Lin, Zhigui; Liu, Jiahong; Pedersen, Michael

    2011-01-01

    In this paper, the cooperating two-species Lotka–Volterra model is discussed. The existence and asymptotic behavior of T -periodic solutions for the periodic reaction diffusion system under homogeneous Dirichlet boundary conditions are first investigated. The blowup properties of solutions...... for the same system are then given. It is shown that periodic solutions exist if the intra-specific competitions are strong whereas blowup solutions exist under certain conditions if the intra-specific competitions are weak. Numerical simulations and a brief discussion are also presented in the last section....

  2. Producing a known neutral particle beam for the purpose of calibrating a neutral particle detector

    International Nuclear Information System (INIS)

    On Earth, gravitational confinement of a plasma is not possible, so plasmas are studied in vacuum chambers where the confinement of the plasma consists mainly of the chamber walls and magnetic fields. Here, the interaction of the plasma with the walls around it is unavoidably significant. The energetic ions and electrons of the plasma strike the walls and a number of different particles leave the surface, most of which are electrically neutral. Sometimes, plasma-surface interactions are beneficial such an in plasma processing. In other cases, the plasma-surface interaction is a hindrance such as in magnetic fusion systems. In either case, it is important to study plasma-surface interactions in order to predict and control its effect on the experimental system. In an effort to understand the composition of the particles leaving the surface, Ph.D. candidate Bruce Cain and Associate Professor David Ruzjc at the University of Illinois have designed and built a system to examine the neutral particles scattered from light ions hitting a surface with a beam energy of 10 to 900 eV. According to the design of the system, the neutral particles are ionized by a glow discharge ionizer and then enter into an energy analyzer. In order to calibrate the ionizer and the energy analyzer, a known particle beam is made by a charge exchange cell that is placed in the path of an ion beam. The design and use of the charge exchange cell is the subject of this paper, which will present the underlying theory, followed by the experimental design, and finally the procedures and the results of the experiments undertaken

  3. Nonlinear dynamics for charges particle beams with a curved axis in the matrix - recursive model

    Energy Technology Data Exchange (ETDEWEB)

    Dymnikov, A.D. [University of St Petersburg, (Russian Federation). Institute of Computational Mathematics and Control Process

    1993-12-31

    In this paper a new matrix and recursive approach has been outlined for treating nonlinear optics of charged particle beams. This approach is a new analytical and computational tool for designers of optimal beam control systems. 9 refs.

  4. The lensing effect of trapped particles in a dual-beam optical trap.

    Science.gov (United States)

    Grosser, Steffen; Fritsch, Anatol W; Kiessling, Tobias R; Stange, Roland; Käs, Josef A

    2015-02-23

    In dual-beam optical traps, two counterpropagating, divergent laser beams emitted from opposing laser fibers trap and manipulate dielectric particles. We investigate the lensing effect that trapped particles have on the beams. Our approach makes use of the intrinsic coupling of a beam to the opposing fiber after having passed the trapped particle. We present measurements of this coupling signal for PDMS particles, as well as a model for its dependence on size and refractive index of the trapped particle. As a more complex sample, the coupling of inhomogeneous biological cells is measured and discussed. We show that the lensing effect is well captured by the simple ray optics approximation. The measurements reveal intricate details, such as the thermal lens effect of the beam propagation in a dual-beam trap. For a particle of known size, the model further allows to infer its refractive index simply from the coupling signal. PMID:25836555

  5. A stochastic-hydrodynamic model of halo formation in charged particle beams

    OpenAIRE

    Petroni, Nicola Cufaro; De Martino, Salvatore; De Siena, Silvio; Illuminati, Fabrizio

    2003-01-01

    The formation of the beam halo in charged particle accelerators is studied in the framework of a stochastic-hydrodynamic model for the collective motion of the particle beam. In such a stochastic-hydrodynamic theory the density and the phase of the charged beam obey a set of coupled nonlinear hydrodynamic equations with explicit time-reversal invariance. This leads to a linearized theory that describes the collective dynamics of the beam in terms of a classical Schr\\"odinger equation. Taking ...

  6. Charged particle therapy with mini-segmented beams

    Directory of Open Access Journals (Sweden)

    F. Avraham eDilmanian

    2015-12-01

    Full Text Available One of the fundamental attributes of proton therapy and carbon ion therapy is the ability of these charged particles to spare tissue distal to the targeted tumor. This significantly reduces normal tissue toxicity and has the potential to translate to a wider therapeutic index. Although, in general, particle therapy also reduces dose to the proximal tissues, particularly in the vicinity of the target, dose to the skin and to other very superficial tissues tends to be higher than that of megavoltage x-rays. The methods presented here, namely Interleaved carbon minibeams and Radiosurgery with arrays of proton and light ion minibeams, both utilize beams segmented into arrays of parallel minibeams of about 0.3 mm incident beam size. These minibeam arrays spare tissues, as demonstrated by synchrotron x-ray experiments. An additional feature of particle minibeams is their gradual broadening due to multiple Coulomb scattering as they penetrate tissues. In the case of interleaved carbon minibeams, which do not broaden much, two arrays of planar carbon minibeams that remain parallel at target depth, are aimed at the target from 90º angles and made to interleave at the target to produce a solid radiation field within the target. As a result the surrounding tissues are exposed only to individual carbon minibeam arrays and are therefore spared. The method was used in four-directional geometry at the NASA Space Radiation Laboratory to ablate a 6.5-mm target in a rabbit brain at a single exposure with 40 Gy physical absorbed dose. Contrast-enhanced magnetic resonance imaging and histology six month later showed very focal target necrosis with nearly no damage to the surrounding brain. As for minibeams of protons and light ions, for which the minibeam broadening is substantial, measurements at MD Anderson Cancer Center in Houston, Texas, and Monte Carlo simulations showed that the broadening minibeams will merge with their neighbors at a certain tissue depth

  7. BLOW-UP OF SOLUTIONS OF THE IGNITION MODEL

    Institute of Scientific and Technical Information of China (English)

    LI Yanling; WU Jianhua

    2002-01-01

    By use of maximum principle and auxiliary function method, the paper discusses the blow-up sets of the solutions of the ignition model in two cases. It is obtained that the solutions blow up in single point in nonsymmetric case and that the solutions blow up totally or at a couple of points in symmetric case.

  8. Blow-up theories for semilinear parabolic equations

    CERN Document Server

    Hu, Bei

    2011-01-01

    There is an enormous amount of work in the literature about the blow-up behavior of evolution equations. It is our intention to introduce the theory by emphasizing the methods while seeking to avoid massive technical computations. To reach this goal, we use the simplest equation to illustrate the methods; these methods very often apply to more general equations.

  9. Blow-up of solution for a generalized Boussinesq equation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper studies the initial boundary value problem for a generalized Boussinesq equation and proves the existence and uniqueness of the local generalized solution of the problem by using the Galerkin method. Moreover, it gives the sufficient conditions of blow-up of the solution in finite time by using the concavity method.

  10. Energy distribution of projectile fragment particles in heavy ion therapeutic beam

    Energy Technology Data Exchange (ETDEWEB)

    Matsufuji, Naruhiro; Tomura, Hiromi; Futami, Yasuyuki [National Inst. of Radiological Sciences, Chiba (Japan)] [and others

    1998-03-01

    Production of fragment particles in a patient`s body is one of important problems for heavy charged particle therapy. It is required to know the yield and the energy spectrum for each fragment element - so called `beam quality` to understand the effect of therapeutic beam precisely. In this study, fragment particles produced by practical therapeutic beam of HIMAC were investigated with using tissue-equivalent material and a detector complex. From the results, fragment particles were well identified by difference of their atomic numbers and the beam quality was derived. Responses of the detectors in this energy region were also researched. (author)

  11. Study of nanoscale structural biology using advanced particle beam microscopy

    Science.gov (United States)

    Boseman, Adam J.

    This work investigates developmental and structural biology at the nanoscale using current advancements in particle beam microscopy. Typically the examination of micro- and nanoscale features is performed using scanning electron microscopy (SEM), but in order to decrease surface charging, and increase resolution, an obscuring conductive layer is applied to the sample surface. As magnification increases, this layer begins to limit the ability to identify nanoscale surface structures. A new technology, Helium Ion Microscopy (HIM), is used to examine uncoated surface structures on the cuticle of wild type and mutant fruit flies. Corneal nanostructures observed with HIM are further investigated by FIB/SEM to provide detailed three dimensional information about internal events occurring during early structural development. These techniques are also used to reconstruct a mosquito germarium in order to characterize unknown events in early oogenesis. Findings from these studies, and many more like them, will soon unravel many of the mysteries surrounding the world of developmental biology.

  12. Power and particle balance during neutral beam injection in TFTR

    International Nuclear Information System (INIS)

    Detailed boundary plasma measurements on TFTR have been made during a NBI power scan in the range Ptot = 1MW--20MW in the L-mode regime. The behavior of the plasma density left-angle ne right-angle, radiated power Prad, carbon and deuterium fluxes ΓC, ΓD, and Ζeff can be summarized as, left-angle ne right-angle ∝ Ptot1/2, Prad, ΓC, ΓD ∝ Ptot, and Ζeff ∼ constant. It is shown that central fuelling by the neutral beams plays a minor role in the particle balance of the discharge. More important is the NBI role in the power balance. The TFTR data during NBI originate primarily at the graphite limiter

  13. Device for measuring charge density distribution in charged particle beams

    International Nuclear Information System (INIS)

    A device to measure charge density distribution in charged particle beams has been described. The device contains a set of hollow interinsulated current-receiving electrodes, recording system, and cooling system. The invention is aimed at the increase of admissible capacity of the beams measured at the expense of cooling efficiency increase. The aim is achieved by the fact, that in the device a dynamic evaporating-condensational cooling of electrodes is realized by means of cooling agent supply in perpendicular to their planes through the tubes introduced inside special cups. Spreading in radial direction over electrode surface the cooling agent gradually and intensively washes the side surface of the cup, after that, it enters the cooling cavity in the form of vapour-liquid mixture. In the cavity the cooling agent, supplied using dispensina and receiving collectors in which vapoUr is condensed, circulates. In the device suggested the surface of electrode cooling is decreased significantly at the expense of side surface of the cups which receives the electrode heat

  14. Radiation pressure cross section exerted on homogenous dielectric spherical particle by zeroth order Mathieu beams

    Science.gov (United States)

    Chafiq, A.; Belafhal, A.

    2016-08-01

    In this paper, we present a full calculation of radiation pressure cross section and optical forces exerted by linearly polarized zeroth order Mathieu beams on homogenous dielectric spherical particle in the framework of generalized Lorenz-Mie theory (GLMT). In this theory, the scattered fields are dependent upon the Mie scattering coefficients and the beam shape coefficients. So a new optical property such as force and torque appears by changing the beam profile and the nature of particle. In this way, this work is devoted to the analysis of both transverse and longitudinal optical forces exerted on a simple dielectric spherical particle by zeroth order Mathieu beams and zeroth order Bessel (which is a particular case of the first beam). Thus, through numerical simulations, we show that zeroth order Mathieu beams can't trap this particle but Bessel beam presents some dimensional stable equilibrium points.

  15. Salivary Gland. Photon beam and particle radiotherapy: Present and future.

    Science.gov (United States)

    Orlandi, Ester; Iacovelli, Nicola Alessandro; Bonora, Maria; Cavallo, Anna; Fossati, Piero

    2016-09-01

    Salivary gland cancers (SGCs) are rare diseases and their treatment depends upon histology, stage and site of origin. Radical surgery is the mainstay of treatment but radiotherapy (RT) plays a key role in both the postoperative and the inoperable setting, as well as in recurrent disease. In the absence of prospective randomized trials, a wide retrospective literature suggests postoperative RT (PORT) in patients with high risk pathological features. SGCs, and adenoid cystic carcinoma (ACC) in particular, are known to be radio-resistant tumors and should therefore respond well to particle beam therapy. Recently, excellent outcome has been reported with radical carbon ion RT (CIRT) in particular for ACC. Both modern photon- and hadron-based treatments are effective and are characterized by a favourable toxicity profile. But it is not clear whether one modality is superior to the other for disease control, due to the differences in patients' selection, techniques, fractionation schedules and outcome measurements among clinical experiences. In this paper, we review the role of photon and particle RT for malignant SGCs, discussing the difference between modalities in terms of biological and technical characteristics. RT dose and target volumes for different histologies (ACC versus non-ACC) have also been taken into consideration. PMID:27394087

  16. Simulation of Particle Fluxes at the DESY-II Test Beam Facility

    International Nuclear Information System (INIS)

    In the course of this Master's thesis ''Simulation of Particle Fluxes at the DESY-II Test Beam Facility'' the test beam generation for the DESY test beam line was studied in detail and simulated with the simulation software SLIC. SLIC uses the Geant4 toolkit for realistic Monte Carlo simulations of particles passing through detector material.After discussing the physics processes relevant for the test beam generation and the principles of the beam generation itself, the software used is introduced together with a description of the functionality of the Geant4 Monte Carlo simulation. The simulation of the test beam line follows the sequence of the test beam generation. Therefore, it starts with the simulation of the beam bunch of the synchrotron accelerator DESY-II, and proceeds step by step with the single test beam line components. An additional benefit of this thesis is the provision of particle flux and trajectory maps, which make fluxes directly visible by following the particle tracks through the simulated beam line. These maps allow us to see each of the test beam line components, because flux rates and directions change rapidly at these points. They will also guide the decision for placements of future test beam line components and measurement equipment.In the end, the beam energy and its spread, and the beam rate of the final test beam in the test beam area were studied in the simulation, so that the results can be compared to the measured beam parameters. The test beam simulation of this Master's thesis will serve as a key input for future test beam line improvements.

  17. Optical force exerted on a Rayleigh particle by a vector arbitrary-order Bessel beam

    Science.gov (United States)

    Yang, Ruiping; Li, Renxian

    2016-07-01

    An analytical description of optical force on a Rayleigh particle by a vector Bessel beam is investigated. Linearly, radially, azimuthally, and circularly polarized Bessel beams are considered. The radial, azimuthal, and axial forces by a vector Bessel beam are numerically simulated. The effect of polarization, order of beams, and half-cone angle to the optical force are mainly discussed. For Bessel beams of larger half-cone angle, the non-paraxiality of beams plays an important role in optical forces. Numerical calculations show that optical forces, especially azimuthal forces, are very sensitive to the polarization of beams.

  18. Low-intensity beam diagnostics with particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Rovelli, A.; Ciavola, G.; Cuttone, G.; Finocchiaro, P.; Raia, G. [INFN-LNS, Via S. Sofia 44/A Catania, 95125 (Italy); De Martinis, C.; Giove, D. [INFN-LASA, Via F.lli Cervi 201 Segrate (Midway Islands), 20090 (Italy)

    1997-01-01

    The measure of low intensity beams at low-medium energy is one of the major challenge in beam diagnostics. This subject is of great interest for the design of accelerator-based medical and radioactive beam facilities. In this paper we discuss new developments in image-based devices to measure low-intensity beams. All the investigated devices must guarantee measurement of the total beam current and its transverse distribution. {copyright} {ital 1997 American Institute of Physics.}

  19. High Intensity Beam Issues in the CERN Proton Synchrotron

    CERN Document Server

    Aumon, Sandra; Rivkin, Leonid

    This PhD work is about limitations of high intensity proton beams observed in the CERN Proton Synchrotron (PS) and, in particular, about issues at injection and transition energies. With its 53 years, the CERN PS would have to operate beyond the limit of its performance to match the future requirements. Beam instabilities driven by transverse impedance and aperture restrictions are important issues for the operation and for the High-Luminosity LHC upgrade which foresees an intensity increase delivered by the injectors. The main subject of the thesis concerns the study of a fast transverse instability occurring at transition energy. The proton beams crossing this energy range are particularly sensitive to wake forces because of the slow synchrotron motion. This instability can cause a strong vertical emittance blow-up and severe losses in less than a synchrotron period. Experimental observations show that the particles at the peak density of the beam longitudinal distribution oscillate in the vertical plane du...

  20. Procedures for the measurement of the extinction cross section of one particle using a Gaussian beam

    Science.gov (United States)

    Bosch, Salvador; Sancho-Parramon, Jordi

    2016-09-01

    Two procedures for the measurement of the extinction cross section (ECS) of one particle using a slightly focused Gaussian beam have been introduced and numerically tested. While the first one relies on previously introduced ideas and has close connection with the optical theorem, the second procedure is new and is mostly related with light measurements where the detector collects much of the energy of the incident beam. Both procedures prove to be valid and somehow complementary up to particle sizes of the order of the beam waist, thus enlarging the capability of simple measurement set-ups based on Gaussian beams for the estimation of the ECS of one particle.

  1. Electron Production and Collective Field Generation in Intense Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Molvik, A W; Vay, J; Cohen, R; Friedman, A; Lee, E; Verboncoeur, J; Covo, M K

    2006-02-09

    Electron cloud effects (ECEs) are increasingly recognized as important, but incompletely understood, dynamical phenomena, which can severely limit the performance of present electron colliders, the next generation of high-intensity rings, such as PEP-II upgrade, LHC, and the SNS, the SIS 100/200, or future high-intensity heavy ion accelerators such as envisioned in Heavy Ion Inertial Fusion (HIF). Deleterious effects include ion-electron instabilities, emittance growth, particle loss, increase in vacuum pressure, added heat load at the vacuum chamber walls, and interference with certain beam diagnostics. Extrapolation of present experience to significantly higher beam intensities is uncertain given the present level of understanding. With coordinated LDRD projects at LLNL and LBNL, we undertook a comprehensive R&D program including experiments, theory and simulations to better understand the phenomena, establish the essential parameters, and develop mitigating mechanisms. This LDRD project laid the essential groundwork for such a program. We developed insights into the essential processes, modeled the relevant physics, and implemented these models in computational production tools that can be used for self-consistent study of the effect on ion beams. We validated the models and tools through comparison with experimental data, including data from new diagnostics that we developed as part of this work and validated on the High-Current Experiment (HCX) at LBNL. We applied these models to High-Energy Physics (HEP) and other advanced accelerators. This project was highly successful, as evidenced by the two paragraphs above, and six paragraphs following that are taken from our 2003 proposal with minor editing that mostly consisted of changing the tense. Further benchmarks of outstanding performance are: we had 13 publications with 8 of them in refereed journals, our work was recognized by the accelerator and plasma physics communities by 8 invited papers and we have 5

  2. Treatment facilities, human resource development, and future prospect of particle beam therapy

    International Nuclear Information System (INIS)

    The number of particle beam therapy facilities is increasing globally. Among the countries practicing particle beam therapy, Japan is one of the leading countries in the field with four operating carbon-ion therapy facilities and ten operating proton therapy facilities. With the increasing number of particle beam therapy facilities, the human resource development is becoming extremely important, and there has been many such efforts including the Gunma University Program for Cultivating Global Leaders in Heavy Ion Therapeutics and Engineering, which aimed to educate and train the radiation oncologists, medical physicists, accelerator engineers, and radiation biologists to become global leaders in the field of particle beam therapy. In the future, the benefit and effectiveness of particle beam therapy should be discussed and elucidated objectively in a framework of comprehensive cancer care. (author)

  3. Blowup Analysis for a Nonlocal Diffusion Equation with Reaction and Absorption

    Directory of Open Access Journals (Sweden)

    Yulan Wang

    2012-01-01

    Full Text Available We investigate a nonlocal reaction diffusion equation with absorption under Neumann boundary. We obtain optimal conditions on the exponents of the reaction and absorption terms for the existence of solutions blowing up in finite time, or for the global existence and boundedness of all solutions. For the blowup solutions, we also study the blowup rate estimates and the localization of blowup set. Moreover, we show some numerical experiments which illustrate our results.

  4. A NOTE ON GRADIENT BLOWUP RATE OF THE INHOMOGENEOUS HAMILTON-JACOBI EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Zhengce ZHANG; Zhenjie LI

    2013-01-01

    The gradient blowup of the equation ut =△u + a(x)[▽u|p + h(x),where p > 2,is studied.It is shown that the gradient blowup rate will never match that of the self-similar variables.The exact blowup rate for radial solutions is established under the assumptions on the initial data so that the solution is monotonically increasing in time.

  5. Stable Self-Similar Blow-Up Dynamics for Slightly {L^2}-Supercritical Generalized KDV Equations

    Science.gov (United States)

    Lan, Yang

    2016-07-01

    In this paper we consider the slightly {L^2}-supercritical gKdV equations {partial_t u+(u_{xx}+u|u|^{p-1})_x=0}, with the nonlinearity {5 blow-up dynamics with self-similar blow-up rate in the energy space {H^1} and give a specific description of the formation of the singularity near the blow-up time.

  6. Numerical study of blow-up in the Davey-Stewartson system

    KAUST Repository

    Klein, Christian

    2013-03-01

    Nonlinear dispersive partial differential equations such as the nonlinear Schrödinger equations can have solutions that blow up. We numerically study the long time behavior and potential blow-up of solutions to the focusing Davey-Stewartson II equation by analyzing perturbations of the lump and the Ozawa solutions. It is shown in this way that both are unstable to blow-up and dispersion, and that blow-up in the Ozawa solution is generic.

  7. Self-modulated dynamics of a relativistic charged particle beam in plasma wake field excitation

    Science.gov (United States)

    Akhter, T.; Fedele, R.; Nicola, S. De; Tanjia, F.; Jovanović, D.; Mannan, A.

    2016-09-01

    The self-modulated dynamics of a relativistic charged particle beam is provided within the context of the theory of plasma wake field excitation. The self-consistent description of the beam dynamics is provided by coupling the Vlasov equation with a Poisson-type equation relating the plasma wake potential to the beam density. An analysis of the beam envelope self-modulation is then carried out and the criteria for the occurrence of the instability are discussed thereby.

  8. Blow-up Dynamics of L2 Solutions for the Davey-Stewartson System

    Institute of Scientific and Technical Information of China (English)

    Shi Hui ZHU

    2015-01-01

    We study the blow-up solutions for the Davey–Stewartson system (D–S system, for short) in L2x(R2). First, we give the nonlinear profile decomposition of solutions for the D–S system. Then, we prove the existence of minimal mass blow-up solutions. Finally, by using the characteristic of minimal mass blow-up solutions, we obtain the limiting profile and a precisely mass concentration of L2 blow-up solutions for the D–S system.

  9. Asymmetric wavelet reconstruction of particle hologram with an elliptical Gaussian beam illumination.

    Science.gov (United States)

    Wu, Xuecheng; Wu, Yingchun; Zhou, Binwu; Wang, Zhihua; Gao, Xiang; Gréhan, Gérard; Cen, Kefa

    2013-07-20

    We propose an asymmetric wavelet method to reconstruct a particle from a hologram illuminated by an elliptical, astigmatic Gaussian beam. The particle can be reconstructed by a convolution of the asymmetric wavelet and hologram. The reconstructed images have the same size and resolution as the recorded hologram; therefore, the reconstructed 3D field is convenient for automatic particle locating and sizing. The asymmetric wavelet method is validated by both simulated holograms of spherical particles and experimental holograms of opaque, nonspherical coal particles.

  10. Studies of aerosol particle formation from various sources using ion and electron beam analytical techniques.

    OpenAIRE

    Gharibi, Arash

    2006-01-01

    The thesis presents the results of studies of aerosol particle formation using ion and electron beam analytical techniques. The sources of aerosol particle formation studied are the following: 1. production of primary aerosol particles in the high Arctic region during summers 2. emission of ultrafine aerosol particles from wear on the road-tire interface 3. emission of aerosol particles from district heating units operating on three commonly-used biofuels. A source...

  11. Understanding the focusing of charged particle for 2D sheet beam in a cusped magnetic field

    CERN Document Server

    Banerjee, Tusharika S; Reddy, K T V

    2016-01-01

    The requirement of axial magnetic field for focusing and transportation of sheet beam using cusped magnets is less as compared to solenoid magnetic fields which is uniform. There is often some confusion about how a cusped magnetic field focuses high current density sheet beam because it is generally understood that non-uniform magnetic field cannot guide the particle beam along its axis of propagation .In this paper, we perform simple analysis of the dynamics of sheet beam in a cusped magnetic field with single electron model and emphasize an intuitive understanding of interesting features (as beam geometry, positioning of permanent magnets, particle radius,particle velocity,radius of curvature of particle inside cusped magnetic field)

  12. Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

    CERN Document Server

    Stancari, Giulio; Redaelli, Stefano

    2014-01-01

    Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.

  13. New Spectral Method for Halo Particle Definition in Intense Mis-matched Beams

    International Nuclear Information System (INIS)

    An advanced spectral analysis of a mis-matched charged particle beam propagating through a periodic focusing transport lattice is utilized in particle-in-cell (PIC) simulations. It is found that the betatron frequency distribution function of a mismatched space-charge-dominated beam has a bump-on-tail structure attributed to the beam halo particles. Based on this observation, a new spectral method for halo particle definition is proposed that provides the opportunity to carry out a quantitative analysis of halo particle production by a beam mismatch. In addition, it is shown that the spectral analysis of the mismatch relaxation process provides important insights into the emittance growth attributed to the halo formation and the core relaxation processes. Finally, the spectral method is applied to the problem of space-charge transport limits.

  14. Modulation of lens cell adhesion molecules by particle beams

    Science.gov (United States)

    McNamara, M. P.; Bjornstad, K. A.; Chang, P. Y.; Chou, W.; Lockett, S. J.; Blakely, E. A.

    2001-01-01

    Cell adhesion molecules (CAMs) are proteins which anchor cells to each other and to the extracellular matrix (ECM), but whose functions also include signal transduction, differentiation, and apoptosis. We are testing a hypothesis that particle radiations modulate CAM expression and this contributes to radiation-induced lens opacification. We observed dose-dependent changes in the expression of beta 1-integrin and ICAM-1 in exponentially-growing and confluent cells of a differentiating human lens epithelial cell model after exposure to particle beams. Human lens epithelial (HLE) cells, less than 10 passages after their initial culture from fetal tissue, were grown on bovine corneal endothelial cell-derived ECM in medium containing 15% fetal bovine serum and supplemented with 5 ng/ml basic fibroblast growth factor (FGF-2). Multiple cell populations at three different stages of differentiation were prepared for experiment: cells in exponential growth, and cells at 5 and 10 days post-confluence. The differentiation status of cells was characterized morphologically by digital image analysis, and biochemically by Western blotting using lens epithelial and fiber cell-specific markers. Cultures were irradiated with single doses (4, 8 or 12 Gy) of 55 MeV protons and, along with unirradiated control samples, were fixed using -20 degrees C methanol at 6 hours after exposure. Replicate experiments and similar experiments with helium ions are in progress. The intracellular localization of beta 1-integrin and ICAM-1 was detected by immunofluorescence using monoclonal antibodies specific for each CAM. Cells known to express each CAM were also processed as positive controls. Both exponentially-growing and confluent, differentiating cells demonstrated a dramatic proton-dose-dependent modulation (upregulation for exponential cells, downregulation for confluent cells) and a change in the intracellular distribution of the beta 1-integrin, compared to unirradiated controls. In contrast

  15. Particle-in-cell mode beam dynamics simulation of the low energy beam transport for the SSC-linac injector

    Institute of Scientific and Technical Information of China (English)

    XIAO Chen; HE Yuan; YUAN You-Jin; YAO Qing-Gao; WANG Zhi-Jun; CHANG Wei; LIU Yong; XIA Jia-Wen

    2011-01-01

    A new SSC-linac system (injector into separated sector cyclotron) is being designed in the HIRFL (heavy ion research facility of Lanzhou). As part of SSC-Linac, the LEBT (low energy beam transport) consists of seven solenoids, four quadrupoles, a bending magnet and an extra multi-harmonic buncher. The total length of this segment is about 7 meters. The beam dynamics in this LEBT has been studied using three-dimensional PIC (particle-in-cell) code BEAMPATH. The simulation results show that the continuous beam from the ion source is first well analyzed by a charge-to-mass selection system, and the beam of the selected charge-to-mass ratio is then efficiently pre-bunched by a multi-harmonic buncher and optimally matched into the RFQ (radio frequency quadrupole) for further acceleration. The principles and effects of the solenoid collimation channel are discussed, and it could limit the beam emittance by changing the aperture size.

  16. Advanced methods for the computation of particle beam transport and the computation of electromagnetic fields and beam-cavity interactions

    International Nuclear Information System (INIS)

    The University of Maryland Dynamical Systems and Accelerator Theory Group carries out research in two broad areas: the computation of charged particle beam transport using Lie algebraic methods and advanced methods for the computation of electromagnetic fields and beam-cavity interactions. Important improvements in the state of the art are believed to be possible in both of these areas. In addition, applications of these methods are made to problems of current interest in accelerator physics including the theoretical performance of present and proposed high energy machines. The Lie algebraic method of computing and analyzing beam transport handles both linear and nonlinear beam elements. Tests show this method to be superior to the earlier matrix or numerical integration methods. It has wide application to many areas including accelerator physics, intense particle beams, ion microprobes, high resolution electron microscopy, and light optics. With regard to the area of electromagnetic fields and beam cavity interactions, work is carried out on the theory of beam breakup in single pulses. Work is also done on the analysis of the high frequency behavior of longitudinal and transverse coupling impedances, including the examination of methods which may be used to measure these impedances. Finally, work is performed on the electromagnetic analysis of coupled cavities and on the coupling of cavities to waveguides

  17. A Numerical Study of Blowup in the Harmonic Map Heat Flow Using the MMPDE Moving Mesh Method

    NARCIS (Netherlands)

    Haynes, R.D.; Huang, W.; Zegeling, P.A.

    2013-01-01

    The numerical solution of the harmonic heat map flow problems with blowup in finite or infinite time is considered using an adaptive moving mesh method. A properly chosen monitor function is derived so that the moving mesh method can be used to simulate blowup and produce accurate blowup profiles wh

  18. Transmission efficiency improvement of the injector line of SFC by particle beam decorrelation

    Institute of Scientific and Technical Information of China (English)

    杨尧; 赵红卫; 原有进; 冯玉成; 孙良亭; 方兴; 卢旺; 张文慧; 曹云; 张雪珍

    2015-01-01

    The operation of the HIRFL accelerator has shown that the beam transmission efficiency of the sector focusing cyclotron (SFC) injector line is rather poor. Beam simulations have been performed to investigate the possible causes for this low transmission. It is predicted that the property of transversal coupling of the ion beam from electron cyclotron resonance (ECR) ion source can be an important factor to degrade the beam quality by increasing the beam emittance, resulting in a serious particle loss. An improved operation scheme for the SECRAL associated line has been proposed, and the corresponding experiment was carried out. This paper presents the test results.

  19. The blowup mechanism for 3-D quasilinear wave equations with small data

    Institute of Scientific and Technical Information of China (English)

    尹会成

    2000-01-01

    For a class of special three-dimensional quasilinear wave equations, we study the blowup mechanism of classical solutions. More precisely, under the nondegenerate conditions, any radially symmetric solution with small initial data is shown to develop singularities in the second order derivatives while the first order derivatives and itself remain continuous, moreover the blowup of solution is of "cusp type".

  20. BLOW-UP OF THE SOLUTION FOR A KIND OF HIGHER ORDER HYPERBOLIC EVOLUTION SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, we give some results on the blow-up behaviors of the solution to the mixed problem for some higher nonlinear hyperbolic evolution equation in finite time. By introducing the "blow-up factor K(u,ut)" we get some new results, which generalize the conclusions of [3] and [4].

  1. BLOW-UP RATE OF SOLUTIONS FOR P-LAPLACIAN EQUATION

    Institute of Scientific and Technical Information of China (English)

    Zhao Junning; Liang Zhilei

    2008-01-01

    In this note we consider the blow-up rate of solutions for p-Laplacian equation with nonlinear source,ut=div(|▽u|p-2▽u)+uq,(x,t)∈RN×(0,T),N≥1.When q>p-1,the blow-up rate of solutions is studied.

  2. Transition between extinction and blow-up in a generalized Fisher–KPP model

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Bermejo, Benito, E-mail: benito.hernandez@urjc.es [Departamento de Física, Universidad Rey Juan Carlos, Calle Tulipán S/N, 28933, Móstoles, Madrid (Spain); Sánchez-Valdés, Ariel [Departamento de Matemática Aplicada, Universidad Rey Juan Carlos, Calle Tulipán S/N, 28933, Móstoles, Madrid (Spain)

    2014-05-01

    Stationary solutions of the Fisher–KPP equation with general nonlinear diffusion and arbitrary reactional kinetic orders terms are characterized. Such stationary (separatrix-like) solutions disjoint the blow-up solutions from those showing extinction. In addition a criterion for general parameter values is presented, which allows determining the blow-up or vanishing character of the solutions.

  3. Remarks on the Blow-Up Solutions for the Critical Gross-Pitaevskii Equation

    Directory of Open Access Journals (Sweden)

    Xiaoguang Li

    2013-01-01

    Full Text Available This paper is concerned with the blow-up solutions of the critical Gross-Pitaevskii equation, which models the Bose-Einstein condensate. The existence and qualitative properties of the minimal blow-up solutions are obtained.

  4. Energy Decaying and Blow-Up of Solution for a Kirchhoff Equation with Strong Damping

    Institute of Scientific and Technical Information of China (English)

    YANG Zhifeng; QIU Dehua

    2009-01-01

    The initial boundary value problem for a Kirchhoff equation with Lipschitz type continuous coefficient is studied on bounded domain. Under some conditions, the energy decaying and blow-up of solution are discussed. By refining method, the exponent decay estimates of the energy function and the estimates of the life span of blow-up solutions are given.

  5. 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.

  6. Particle Rate and Host Accelerator Beam Loss on the MICE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Adam James [Imperial Coll., London; 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.

  7. [Advanced development of particle beam probe diagnostic system

    International Nuclear Information System (INIS)

    This progress report under DOE Grant DE-FG02-85ER3211 covers the period 15 December 1992 through 15 October 1993. The major accomplishments of this period are summarized below: The basic TEXT heavy ion beam probe including the primary beam line, the upper secondary beam line with the old 500 keV analyzer, and the lower secondary beam line with the new 2 MeV analyzer is operational and system shake-down is now beginning. Several subsystems of the complete system design are still under development, including secondary beam line sweeps, primary beam detectors, the digital control and data acquisition system. The lower analyzer entrance aperture and detector plates also have very limited capabilities to make it possible to more rapidly obtain satisfactory initial alignment and calibration conditions. We have performed a variety of high voltage tests that establish the basic efficacy of the 2 MeV analyzer design. We have upgraded the ion optics and added vacuum chambers in our vertical test stand facility to allow us to test the 2 MeV analyzers. We have also constructed a facility for testing ion source characteristics. We analyzed data on primary beam modulation taken during the last run period and confirmed the accuracy of our simulation code. Analysis of magnetic field measurements continued

  8. Thermo-mechanical modelling of high energy particle beam impacts

    CERN Document Server

    Scapin, M; Dallocchio, A

    2010-01-01

    The unprecedented energy intensities of modern hadron accelerators yield special problems with the materials that are placed close to or into the high intensity beams. The energy stored in LHC in a single beam is equivalent to about 80 kg of TNT explosive, stored in a transverse beam area of 0.2 mm×0.2 mm. The materials placed close to the beam are used at, or even beyond, their damage limits. However, it is very difficult to predict structural efficiency and robustness accurately: beam-induced damage occurs in a regime where practical experience does not exist. This study is performed in order to estimate the damage on a copper component due to the impact with a 7 TeV proton beam generated by LHC. The case study represents an accidental case consequent to an abnormal release of the beam, in which 8 bunches irradiate the target directly. The energy delivered on the component is calculated using the FLUKA code and then used as input in the numerical simulations, that are carried out via the FEM code LS-DYNA. ...

  9. Frontiers of particle beam and high energy density plasma science using pulse power technology

    International Nuclear Information System (INIS)

    The papers presented at the symposium on “Frontiers of Particle Beam and High Energy Density Plasma Science using Pulse Power Technology” held in November 20-21, 2009 at National Institute for Fusion Science are collected. The papers reflect the present status and resent progress in the experiment and theoretical works on high power particle beams and high energy density plasmas produced by pulsed power technology. (author)

  10. Advanced charged particle beam ignited nuclear pulse propulsion

    Science.gov (United States)

    Winterberg, F.

    2009-06-01

    It is shown that the mass of the driver for nuclear microexplosion—Orion type—pulse propulsion can be substantially reduced with a special fusion-fast fission configuration, which permits to replace an inefficient laser beam driver with a much more efficient and less massive relativistic electron beam (or light ion beam) driver. The driver mass can be further reduced, and the propulsion efficiency increased, by surrounding the nuclear microexplosion assembly with a shell of conventional hydrogen-rich explosive, helping to ignite the nuclear reaction and dissipating the otherwise lost kinetic neutron energy in the shell which becomes part of the propellant.

  11. A Crack Identification Method For Beam Type Structures Subject To Moving Vehicle Using Particle Swarm Optimization

    OpenAIRE

    GÖKDAĞ, Hakan

    2013-01-01

    In this work a crack identification method for beam type structures under moving vehicle is proposed. The basic of the method is to formulate damage detection as an inverse problem, and solve for damage locations and extents. To this end, an objective function is defined based on the difference of damaged beam dynamic response and the response calculated by the mathematical model of the beam. The optimization problem is solved through a popular evolutionary algorithm, i.e. the particle swarm ...

  12. Characterisation of gunshot residue particles using self-consistent ion beam analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, M.J. [University of Surrey Ion Beam Centre, Guildford, GU2 7XH (United Kingdom)], E-mail: m.bailey@surrey.ac.uk; Jeynes, C. [University of Surrey Ion Beam Centre, Guildford, GU2 7XH (United Kingdom)

    2009-06-15

    Individual particles of gunshot residue were studied with particle-induced X-ray emission and backscattering spectrometry using a 2.5 MeV H{sup +} beam focussed to {approx}4 {mu}m and self-consistent fitting of the data. The geometry of these spherical particles was considered in order to accurately fit the corresponding particle spectrum and therefore to quantify the trace element composition of these particles. The demonstrable self-consistency of this method allows the compositions of most residue particles to be determined unambiguously and with a higher sensitivity to trace elements than conventional methods.

  13. Characterisation of gunshot residue particles using self-consistent ion beam analysis

    International Nuclear Information System (INIS)

    Individual particles of gunshot residue were studied with particle-induced X-ray emission and backscattering spectrometry using a 2.5 MeV H+ beam focussed to ∼4 μm and self-consistent fitting of the data. The geometry of these spherical particles was considered in order to accurately fit the corresponding particle spectrum and therefore to quantify the trace element composition of these particles. The demonstrable self-consistency of this method allows the compositions of most residue particles to be determined unambiguously and with a higher sensitivity to trace elements than conventional methods.

  14. Universality of the blow-up profile for small type II blow-up solutions of energy-critical wave equation: the non-radial case

    CERN Document Server

    Duyckaerts, Thomas; Merle, Frank

    2010-01-01

    Following our previous paper in the radial case, we consider blow-up type II solutions to the energy-critical focusing wave equation. Let W be the unique radial positive stationary solution of the equation. Up to the symmetries of the equation, under an appropriate smallness assumption, any type II blow-up solution is asymptotically a regular solution plus a rescaled Lorentz transform of W concentrating at the origin.

  15. Frontiers of particle beams: Factories with e+e- rings

    International Nuclear Information System (INIS)

    The present volume is the proceedings of the latest of these joint schools, held in Benalmadena, Spain. This course dealt with the design and development of high performance ''factories'' using e+e- colliders. Topics covered were: physics motivation, overall design of factories and their detectors, high luminosity injection, short bunches, instabilities, feedback, beam-beam interaction, lattice and interaction-region design, special schemes, RF, vacuum, ion clearing and background. See hints under the relevant topics. (orig.)

  16. High performance stream computing for particle beam transport simulations

    Energy Technology Data Exchange (ETDEWEB)

    Appleby, R; Bailey, D; Higham, J; Salt, M [School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)], E-mail: Robert.Appleby@manchester.ac.uk, E-mail: David.Bailey-2@manchester.ac.uk

    2008-07-15

    Understanding modern particle accelerators requires simulating charged particle transport through the machine elements. These simulations can be very time consuming due to the large number of particles and the need to consider many turns of a circular machine. Stream computing offers an attractive way to dramatically improve the performance of such simulations by calculating the simultaneous transport of many particles using dedicated hardware. Modern Graphics Processing Units (GPUs) are powerful and affordable stream computing devices. The results of simulations of particle transport through the booster-to-storage-ring transfer line of the DIAMOND synchrotron light source using an NVidia GeForce 7900 GPU are compared to the standard transport code MAD. It is found that particle transport calculations are suitable for stream processing and large performance increases are possible. The accuracy and potential speed gains are compared and the prospects for future work in the area are discussed.

  17. High performance stream computing for particle beam transport simulations

    Science.gov (United States)

    Appleby, R.; Bailey, D.; Higham, J.; Salt, M.

    2008-07-01

    Understanding modern particle accelerators requires simulating charged particle transport through the machine elements. These simulations can be very time consuming due to the large number of particles and the need to consider many turns of a circular machine. Stream computing offers an attractive way to dramatically improve the performance of such simulations by calculating the simultaneous transport of many particles using dedicated hardware. Modern Graphics Processing Units (GPUs) are powerful and affordable stream computing devices. The results of simulations of particle transport through the booster-to-storage-ring transfer line of the DIAMOND synchrotron light source using an NVidia GeForce 7900 GPU are compared to the standard transport code MAD. It is found that particle transport calculations are suitable for stream processing and large performance increases are possible. The accuracy and potential speed gains are compared and the prospects for future work in the area are discussed.

  18. UNIFORM BLOW-UP PROFILES FOR HEAT EQUATIONS WITH COUPLING NONLOCAL SOURCES OF ASYMMETRIC MIXED TYPE NONLINEARITIES

    Institute of Scientific and Technical Information of China (English)

    Kong Linghua; Wang Jinhuan; Zheng Sining

    2012-01-01

    This article deals with a nonlocal heat system subject to null Dirichlet boundary conditions,where the coupling nonlocal sources consist of mixed type asymmetric nonlinearities.We at first give the criterion for simultaneous blow-up of solutions,and then establish the uniform blow-up profiles of solutions near the blow-up time.It is observed that not only the simultaneous blow-up rates of the two components u and v are asymmetric,but also the blow-up rates of the same component u (or v) may be in different levels under different dominations.

  19. Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge

    International Nuclear Information System (INIS)

    The purpose of this course is to provide a comprehensive introduction to the physics of beams with intense space charge. This course is suitable for graduate students and researchers interested in accelerator systems that require sufficient high intensity where mutual particle interactions in the beam can no longer be neglected. This course is intended to give the student a broad overview of the dynamics of beams with strong space charge. The emphasis is on theoretical and analytical methods of describing the acceleration and transport of beams. Some aspects of numerical and experimental methods will also be covered. Students will become familiar with standard methods employed to understand the transverse and longitudinal evolution of beams with strong space charge. The material covered will provide a foundation to design practical architectures. In this course, we will introduce you to the physics of intense charged particle beams, focusing on the role of space charge. The topics include: particle equations of motion, the paraxial ray equation, and the Vlasov equation; 4-D and 2-D equilibrium distribution functions (such as the Kapchinskij-Vladimirskij, thermal equilibrium, and Neuffer distributions), reduced moment and envelope equation formulations of beam evolution; transport limits and focusing methods; the concept of emittance and the calculation of its growth from mismatches in beam envelope and from space-charge non-uniformities using system conservation constraints; the role of space-charge in producing beam halos; longitudinal space-charge effects including small amplitude and rarefaction waves; stable and unstable oscillation modes of beams (including envelope and kinetic modes); the role of space charge in the injector; and algorithms to calculate space-charge effects in particle codes. Examples of intense beams will be given primarily from the ion and proton accelerator communities with applications from, for example, heavy-ion fusion, spallation

  20. Parallel Computation of Persistent Homology using the Blowup Complex

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Ryan [Stanford Univ., CA (United States); Morozov, Dmitriy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-04-27

    We describe a parallel algorithm that computes persistent homology, an algebraic descriptor of a filtered topological space. Our algorithm is distinguished by operating on a spatial decomposition of the domain, as opposed to a decomposition with respect to the filtration. We rely on a classical construction, called the Mayer--Vietoris blowup complex, to glue global topological information about a space from its disjoint subsets. We introduce an efficient algorithm to perform this gluing operation, which may be of independent interest, and describe how to process the domain hierarchically. We report on a set of experiments that help assess the strengths and identify the limitations of our method.

  1. Cones of divisors of blow-ups of projective spaces

    Directory of Open Access Journals (Sweden)

    Salvatore Cacciola

    2011-12-01

    Full Text Available We investigate Mori dream spaces obtained by blowing-up the n-dimensional complex projective space at n + 1, n + 2 or n + 3 points in very general position. Using toric techniques we study the movable cone of the blow-up of Pn at n + 1 points, its decomposition into nef chambers and the action of the Weyl group on the set of chambers. Moreover, using different methods, we explicitly write down the equations of the movablecone also for Pn blown-up at n + 2 points.

  2. Blow-up and control of marginally separated boundary layers.

    Science.gov (United States)

    Braun, Stefan; Kluwick, Alfred

    2005-05-15

    Interactive solutions for steady two-dimensional laminar marginally separated boundary layers are known to exist up to a critical value Gamma(c) of the controlling parameter (e.g. the angle of attack of a slender airfoil) Gamma only. Here, we investigate three-dimensional unsteady perturbations of such boundary layers, assuming that the basic flow is almost critical, i.e. in the limit Gamma(c)-Gamma-->0. It is then shown that the interactive equations governing such perturbations simplify significantly, allowing, among others, a systematic study of the blow-up phenomenon observed in earlier investigations and the optimization of devices used in boundary-layer control.

  3. Laser beam manifold and particle photography system for use in fluid velocity measurements

    Science.gov (United States)

    Owen, R. B.; Campbell, C. W.

    1980-01-01

    A laser beam manifold and particle photography system has been developed for use in fluid velocity measurements. The laser manifold is a device which transforms a single laser beam into several uniform parallel beams. By orienting two manifolds mutually perpendicular, an optical grid can be formed which acts as a reference for fluid velocity measurements. This optical grid is for all practical purposes totally nonperturbing to the flow. Tracer particles moving in the plane of the grid are then photographed to yield fluid velocities that can be measured relative to the optical grid. System construction and theory are presented.

  4. Internal composition of atmospheric dust particles from focused ion-beam scanning electron microscopy.

    Science.gov (United States)

    Conny, Joseph M

    2013-08-01

    Use of focused ion-beam scanning electron microscopy (FIB-SEM) to investigate the internal composition of atmospheric particles is demonstrated for assessing particle optical properties. In the FIB-SEM instrument equipped with an X-ray detector, a gallium-ion beam mills the particle, while the electron beam images the slice faces and energy-dispersive X-ray spectroscopy provides element maps of the particle. Differences in assessments of optical behavior based on FIB-SEM and conventional SEM were shown for five selected urban dust particles. The benefit of FIB-SEM for accurately determining the depth and size of optically important phases within particles was shown. FIB-SEM revealed that iron oxide grains left undetected by conventional SEM could potentially shift the single-scattering albedo of the particle from negative to positive radiative forcing. Analysis of a coke-like particle showed that 73% of the light-scattering inclusion went undetected with conventional SEM, causing the bulk absorption coefficient to vary by as much as 25%. Optical property calculations for particles as volume-equivalent spheres and as spheroids that approximated actual particle shapes revealed that the largest effect between conventional SEM and FIB-SEM analyses was on backscattering efficiency, in some cases varying several-fold. PMID:23763344

  5. Development of 2D particle-in-cell code to simulate high current, low energy beam in a beam transport system

    Indian Academy of Sciences (India)

    S C L Srivastava; S V L S Rao; P Singh

    2007-10-01

    A code for 2D space-charge dominated beam dynamics study in beam transport lines is developed. The code is used for particle-in-cell (PIC) simulation of -uniform beam in a channel containing solenoids and drift space. It can also simulate a transport line where quadrupoles are used for focusing the beam. Numerical techniques as well as the results of beam dynamics studies are presented in the paper.

  6. Biomedical applications of medium energy particle beams at LAMPF

    International Nuclear Information System (INIS)

    At LAMPF an 800-MeV proton accelerator is used to produce intense beams of secondary protons, pi mesons, and muons which are being employed in several areas of biomedical research. The primary proton beam is used to produce short-lived radioisotopes of clinical interest. Carefully tailored secondary proton beams are used to obtain density reconstructions of samples with a dose much less than that required by x-ray CT scanners. The elemental composition of tissue samples is being determined non-destructively with muonic x-ray analysis. Finally, an extensive program, with physical, biological, and clinical components, is underway to evaluate negative pi mesons for use in cancer radiotherapy. The techniques used in these experiments and recent results are described

  7. Some fundamental aspects of fluctuations and coherence in charged-particle beams in storage rings

    International Nuclear Information System (INIS)

    A conceptual survey and exposition is presented of some fundamental aspects of fluctuations and coherence, as well as the interplay between the two, in coasting charged-particle beams - both continuous and bunched - in storage rings. A detailed study is given of the spectral properties of the incoherent phase-space Schottky fluctuations, their propagation as waves in the beam, and the analytic complex coherent beam electromagnetic response or transfer function. The modification or distortion of these by collective interactions is examined in terms of simple regeneration mechanisms. Collective or coherent forces in the beam-storage-ring system are described by defining suitable impedance functions or propagators, and a brief discussion of the coherent collective modes and their stability is provided, including a general and rigorous description of the Nyquist stability criterion. The nature of the critical fluctuations near an instability threshold is explored. The concept of Landau damping and its connection with phase-mixing within the beam is outlined. The important connection between the incoherent fluctuations and the beam response, namely the Fluctuation-Dissipation relation, is revealed. A brief discussion is given of the information degrees of freedom, and effective temperature of the fluctuation signals. Appendices provide a short resume of some general aspects of various interactions in a charged-particle beam-environment system in a storage ring and a general introduction to kinetic theory as applied to particle beams. (orig.)

  8. Instrument for spatially resolved simultaneous measurements of forces and currents in particle beams

    Science.gov (United States)

    Spethmann, A.; Trottenberg, T.; Kersten, H.

    2015-01-01

    The article presents a device for spatially resolved and simultaneous measurements of forces and currents in particle beams, especially in beams composed of ions and neutral atoms. The forces are exerted by the impinging beam particles on a plane circular conductive target plate of 20 mm diameter mounted on a pendulum with electromagnetic force compensation. The force measurement in the micronewton range is achieved by electromagnetic compensation by means of static Helmholtz coils and permanent magnets attached to the pendulum. Exemplary measurements are performed in the 1.2 keV beam of a broad beam ion source. The simultaneous measurements of forces and currents onto the same target are compared with each other and with Faraday cup measurements.

  9. Instrument for spatially resolved simultaneous measurements of forces and currents in particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Spethmann, A., E-mail: spethmann@physik.uni-kiel.de; Trottenberg, T., E-mail: trottenberg@physik.uni-kiel.de; Kersten, H., E-mail: kersten@physik.uni-kiel.de [Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel (Germany)

    2015-01-15

    The article presents a device for spatially resolved and simultaneous measurements of forces and currents in particle beams, especially in beams composed of ions and neutral atoms. The forces are exerted by the impinging beam particles on a plane circular conductive target plate of 20 mm diameter mounted on a pendulum with electromagnetic force compensation. The force measurement in the micronewton range is achieved by electromagnetic compensation by means of static Helmholtz coils and permanent magnets attached to the pendulum. Exemplary measurements are performed in the 1.2 keV beam of a broad beam ion source. The simultaneous measurements of forces and currents onto the same target are compared with each other and with Faraday cup measurements.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-15

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

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

    Science.gov (United States)

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

    2009-11-01

    The use of radiochromic films as a simple and inexpensive tool to accurately measure and analyze the beam profile of charged particle accelerators is described. In this study, metallic foils of different materials and thicknesses were irradiated with 17.8MeV protons and autoradiographic images of the beam strike were acquired by exposing pieces of RCF in direct contact with the irradiated foils. The films were digitalized using a conventional scanner and images were analyzed using DoseLab. Beam intensity distributions, isodose curves and linear beam profiles of the digitalized images were acquired. PMID:19054679

  12. Impact of beam ions on α-particle measurements by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Egedal, J.; Bindslev, H.; Budny, R.V.;

    2005-01-01

    Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask...... the measurements of the fusion products. We apply a new technique for calculating the orbit averaged source, (S), of beam ions for various ITER scenarios. With the known (S) Fokker-Planck modelling is applied to characterize the beam ions during the slowing down process. Theoretical CTS signals for both beam ions...

  13. Damping of rotating beams with particle dampers: Discrete element method analysis

    Science.gov (United States)

    Els, D. N. J.

    2013-06-01

    The performance of particle dampers (PDs) under centrifugal loads was investigated. A test bench consisting of a rotating cantilever beam with a particle damper at the tip was developed (D. N. J. Els, AIAA Journal 49, 2228-2238 (2011)). Equal mass containers with different depths, filled with a range of uniform-sized steel ball bearings, were used as particle dampers. The experiments were duplicated numerically with a discrete element method (DEM) model, calibrated against the experimental data. The DEM model of the rotating beam with a PD at the tip captured the performance of the PD very well over a wide range of tests with different configurations and rotation velocities.

  14. A particle-in-cell mode beam dynamics simulation of medium energy beam transport for the SSC-Linac

    Science.gov (United States)

    Xiao, Chen; He, Yuan; Yuan, You-Jin; Lu, Yuan-Rong; Liu, Yong; Wang, Zhi-Jun; Du, Xiao-Nan; Yao, Qing-Gao; Liu, Ge; Xu, Meng-Xin; He, Shou-Bo; Xia, Jia-Wen

    2012-01-01

    A new linear accelerator system, called the SSC-Linac injector, is being designed at HIRFL (the heavy ion research facility of Lanzhou). As part of the SSC-Linac, the medium energy beam transport (MEBT) consists of seven magnetic quadrupoles, a re-buncher and a diagnose box. The total length of this segment is about 1.75 m. The beam dynamics simulation in MEBT has been studied using the TRACK 3D particle-in-cell code, and the simulation result shows that the beam accelerated from the radio frequency quadrupole (RFQ) matches well with the acceptance of the following drift tube linac (DTL) in both the transverse and longitudinal phase spaces, and that most of the particles can be captured by the final sector focusing cyclotron for further acceleration. The longitudinal emittance of the RFQ and the longitudinal acceptance of the DTL was calculated in detail, and a multi-particle beam dynamics simulation from the ion source to the end of the DTL was done to verify the original design.

  15. Single beam optical conveyor belt for chiral particles

    CERN Document Server

    Fernandes, David E

    2016-01-01

    We propose a novel paradigm to selectively manipulate and transport small engineered chiral particles and discriminate different enantiomers using unstructured chiral light. It is theoretically shown that the response of a chiral metamaterial particle may be tailored to enable an optical conveyor belt operation with no optical traps, such that for a fixed incident light helicity and independent of the nanoparticle location, it is either steadily pushed towards the direction of the photon flow or steadily pulled against the photon flow. Our findings create new opportunities for unconventional optical manipulations of tailored nanoparticles and may have applications in sorting racemic mixtures of artificial chiral molecules and in particle delivery.

  16. Plasmas in particle accelerators: adiabatic theories for bunched beams

    International Nuclear Information System (INIS)

    Three different formalisms for discussing Vlasov's equation for bunched beam problems with anharmonic space charge forces are outlined. These correspond to the use of a drift kinetic equation averaged over random betatron motions; a fluidkinetic adiabatic regime analogous to the theory of Chew, Goldberger, and Low; and an adiabatic hydrodynamic theory

  17. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.;

    2011-01-01

    We have studied sulfuric acid aerosol nucleation in an atmospheric pressure reaction chamber using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear contribution from ion-induced nucleation and consider this to be the first unambiguous observation of the ion...

  18. Beam optics and lattice design for particle accelerators

    OpenAIRE

    Holzer, Bernhard J.

    2013-01-01

    The goal of this manuscript is to give an introduction into the design of the magnet lattice and as a consequence into the transverse dynamics of the particles in a synchrotron or storage ring. Starting from the basic principles of how to design the geometry of the ring we will briefly review the transverse motion of the particles and apply this knowledge to study the layout and optimization of the principal elements, namely the lattice cells. The detailed arrangement of the accelerator magne...

  19. Perpendicular Diffusion in the Transport of Solar Energetic Particles from Unconnected Sources: The Counter-streaming Particle Beams Revisited

    CERN Document Server

    He, H -Q

    2015-01-01

    In some solar energetic particle (SEP) events, a counter-streaming particle beam with a deep depression of flux near 90 degrees pitch angle during the beginning phase is observed. Two different interpretations exist in the community to explain this interesting phenomenon. One explanation invokes the hypothesis of an outer reflecting boundary or a magnetic mirror beyond the observer. The other one considers the effect of the perpendicular diffusion on the transport process of SEPs in the interplanetary space. In this work, we revisit the problem of the counter-streaming particle beams observed in SEP events and discuss the possible mechanisms responsible for the formation of this phenomenon. We clarify some results in previous works.

  20. Gas dynamics considerations in a non-invasive profile monitor for charged particle beams

    CERN Document Server

    Tzoganis, Vasilis; Welsch, Carsten P

    2014-01-01

    A non-invasive, gas jet-based, beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This allows on-line measurement of the 2-dimensional transverse profile of particle beams with negligible disturbance to either primary beam or accelerator vacuum. The monitor is suitable for use with beams across a wide range of energies and intensities. In this setup a nozzle-skimmer system shapes a thin supersonic gas jet into a curtain. However, the small dimensions of the gas inlet nozzle and subsequent skimmers were shown to be the cause of many operational problems. In this paper, the dynamics of gas jet formation transport and shaping is discussed before an image-processing based alignment technique is introduced. Furthermore, experimental results obtained with a 5 keV electron beam are discussed and the effects of gas stagnation pressure on the acquired beam are presented.

  1. Plasma opening switch experiments on the Particle Beam Accelerator II

    International Nuclear Information System (INIS)

    Plasma opening switch (POS) experiments have been done since 1986 on the PBFA-II ion beam accelerator to develop a rugged POS that will open rapidly (80%) into a high impedance (> 10 ohm) load. In a recent series of experiments on PBFA II, the authors have developed and tested three different switch designs that use magnetic fields to control and confine the injected plasma. All three configurations couple current efficiently to a 5-ohm electron beam diode. In this experimental series, the PBFA-II Delta Series, more extensive diagnostics were used than in previous switch experiments on PBFA II or on the Blackjack 5 accelerator at Maxwell Laboratories. Data from the experiments with these three switch designs is presented

  2. On the blow-up solutions for the nonlinear fractional Schrödinger equation

    Science.gov (United States)

    Zhu, Shihui

    2016-07-01

    This paper is dedicated to the blow-up solutions for the nonlinear fractional Schrödinger equation arising from pseudorelativistic Boson stars. First, we compute the best constant of a gG-N inequality by the profile decomposition theory and variational arguments. Then, we find the sharp threshold mass of the existence of finite-time blow-up solutions. Finally, we study the dynamical properties of finite-time blow-up solutions around the sharp threshold mass by giving a refined compactness lemma.

  3. A Finite Difference Scheme for Blow-Up Solutions of Nonlinear Wave Equations

    Institute of Scientific and Technical Information of China (English)

    Chien-Hong

    2010-01-01

    We consider a finite difference scheme for a nonlinear wave equation, whose solutions may lose their smoothness in finite time, i.e., blow up in finite time. In order to numerically reproduce blow-up solutions, we propose a rule for a time-stepping,which is a variant of what was successfully used in the case of nonlinear parabolic equations. A numerical blow-up time is defined and is proved to converge, under a certain hypothesis, to the real blow-up time as the grid size tends to zero.

  4. A unified approach of blow-up phenomena for two-dimensional singular Liouville systems

    OpenAIRE

    Battaglia, Luca; Pistoia, Angela

    2016-01-01

    We consider generic 2 x 2 singular Liouville systems on a smooth bounded domain in the plane having some symmetry with respect to the origin. We construct a family of solutions to which blow-up at the origin and whose local mass at the origin is a given quantity depending on the parameters of the system. We can get either finitely many possible blow-up values of the local mass or infinitely many. The blow-up values are produced using an explicit formula which involves Chebyshev polynomials.

  5. A particle swarm optimization algorithm for beam angle selection in intensity-modulated radiotherapy planning

    International Nuclear Information System (INIS)

    Automatic beam angle selection is an important but challenging problem for intensity-modulated radiation therapy (IMRT) planning. Though many efforts have been made, it is still not very satisfactory in clinical IMRT practice because of overextensive computation of the inverse problem. In this paper, a new technique named BASPSO (Beam Angle Selection with a Particle Swarm Optimization algorithm) is presented to improve the efficiency of the beam angle optimization problem. Originally developed as a tool for simulating social behaviour, the particle swarm optimization (PSO) algorithm is a relatively new population-based evolutionary optimization technique first introduced by Kennedy and Eberhart in 1995. In the proposed BASPSO, the beam angles are optimized using PSO by treating each beam configuration as a particle (individual), and the beam intensity maps for each beam configuration are optimized using the conjugate gradient (CG) algorithm. These two optimization processes are implemented iteratively. The performance of each individual is evaluated by a fitness value calculated with a physical objective function. A population of these individuals is evolved by cooperation and competition among the individuals themselves through generations. The optimization results of a simulated case with known optimal beam angles and two clinical cases (a prostate case and a head-and-neck case) show that PSO is valid and efficient and can speed up the beam angle optimization process. Furthermore, the performance comparisons based on the preliminary results indicate that, as a whole, the PSO-based algorithm seems to outperform, or at least compete with, the GA-based algorithm in computation time and robustness. In conclusion, the reported work suggested that the introduced PSO algorithm could act as a new promising solution to the beam angle optimization problem and potentially other optimization problems in IMRT, though further studies need to be investigated

  6. A particle-in-cell mode beam dynamics simulation of medium energy beam transport for the SSC-Linac

    Institute of Scientific and Technical Information of China (English)

    XIAO Chen; XU Meng-Xin; HE Shou-Bo; XIA Jia-Wen; HE Yuan; YUAN You-Jin; LU Yuan-Rong; LIU Yong; WANG Zhi-Jun; DU Xiao-Nan; YAO Qing-Gao; LIU Ge

    2012-01-01

    A new linear accelerator system,called the SSC-Linac injector,is being designed at HIRFL (the heavy ion research facility of Lanzhou).As part of the SSC-Linac,the medium energy beam transport (MEBT) consists of seven magnetic quadrupoles,a re-buncher and a diagnose box.The total length of this segment is about 1.75 m.The beam dynamics simulation in MEBT has been studied using the TRACK 3D particlein-cell code,and the simulation result shows that the beam accelerated from the radio frequency quadrupole (RFQ) matches well with the acceptance of the following drift tube linac (DTL) in both the transverse and longitudinal phase spaces,and that most of the particles can be captured by the final sector focusing cyclotronfor further acceleration.The longitudinal emittance of the RFQ and the longitudinal acceptance of the DTL was calculated in detail,and a multi-particle beam dynamics simulation from the ion source to the end of the DTL was done to verify the original design.

  7. Enhanced Optical Cooling of Particle Beams in Storage Rings

    CERN Document Server

    Bessonov, E G

    2007-01-01

    A method of enhanced optical cooling (EOC) based on nonlinear selective interaction between particles and theirs amplified undulator radiation wavelets (URW) in storage rings is discussed. It leads to non-exponential fast damping. The selectivity is arranged by a moving screen located on the image plane of the optical system projecting URW there.

  8. A Particle In Cell code development for high current ion beam transport and plasma simulations

    CERN Document Server

    Joshi, N

    2016-01-01

    A simulation package employing a Particle in Cell (PIC) method is developed to study the high current beam transport and the dynamics of plasmas. This package includes subroutines those are suited for various planned projects at University of Frankfurt. In the framework of the storage ring project (F8SR) the code was written to describe the beam optics in toroidal magnetic fields. It is used to design an injection system for a ring with closed magnetic field lines. The generalized numerical model, in Cartesian coordinates is used to describe the intense ion beam transport through the chopper system in the low energy beam section of the FRANZ project. Especially for the chopper system, the Poisson equation is implemented with irregular geometries. The Particle In Cell model is further upgraded with a Monte Carlo Collision subroutine for simulation of plasma in the volume type ion source.

  9. Self-modulation of a relativistic charged-particle beam as thermal matter wave envelope

    International Nuclear Information System (INIS)

    The self-modulation, resulting from its interaction with the surrounding medium, of a relativistic charged-particle beam traveling through an overdense plasma, is investigated theoretically. The description of the transverse nonlinear and collective beam dynamics of an electron (or positron) beam in a plasma-based accelerator is provided in terms of a thermal matter wave envelope propagation. This is done using the quantum-like description provided by the thermal wave model. It is shown that the charged-particle beam dynamics is governed by a Zakharov-type system of equations, comprising a nonlinear Schrödinger equation that is governing the spatiotemporal evolution of the thermal matter wave envelope and a Poisson-like equation for the wake potential that is generated by the bunch itself

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

    CERN Document Server

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

    1999-01-01

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

  11. 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:/...

  12. Particle manipulation with acoustic vortex beam induced by a brass plate with spiral shape structure

    Science.gov (United States)

    Wang, Tian; Ke, Manzhu; Li, Weiping; Yang, Qian; Qiu, Chunyin; Liu, Zhengyou

    2016-09-01

    In this work, we give direct demonstration of acoustic radiation force and acoustic torque on particles exerted by an acoustic vortex beam, which is realized by an acoustic artificial structure plate instead of traditional transducer arrays. First, the first order acoustic vortex beam, which has the distinctive features of a linear and continuous phase variation from -π to π around its propagation axis and a magnitude null at its core, is obtained through one single acoustic source incident upon a structured brass plate with Archimedean spiral grating engraved on the back surface. Second, annular self-patterning of polystyrene particles with a radius of 90 μm is realized in the gradient field of this acoustic vortex beam. In addition, we further exhibit acoustic angular momentum transfer to an acoustic absorptive matter, which is verified by a millimeter-sized polylactic acid disk self-rotating in water in the acoustic field of the generated vortex beam.

  13. Three-dimensional particle simulation of heavy-ion fusion beams

    International Nuclear Information System (INIS)

    The beams in a heavy-ion-beam-driven inertial fusion (HIF) accelerator are collisionless, nonneutral plasmas, confined by applied magnetic and electric fields. These space-charge-dominated beams must be focused onto small (few mm) spots at the fusion target, and so preservation of a small emittance is crucial. The nonlinear beam self-fields can lead to emittance growth, and so a self-consistent field description is needed. To this end, a multidimensional particle simulation code, WARP [Friedman et al., Part. Accel. 37-38, 131 (1992)], has been developed and is being used to study the transport of HIF beams. The code's three-dimensional (3-D) package combines features of an accelerator code and a particle-in-cell plasma simulation. Novel techniques allow it to follow beams through many accelerator elements over long distances and around bends. This paper first outlines the algorithms employed in WARP. A number of applications and corresponding results are then presented. These applications include studies of: beam drift-compression in a misaligned lattice of quadrupole focusing magnets; beam equilibria, and the approach to equilibrium; and the MBE-4 experiment [AIP Conference Proceedings 152 (AIP, New York, 1986), p. 145] recently concluded at Lawrence Berkeley Laboratory (LBL). Finally, 3-D simulations of bent-beam dynamics relevant to the planned Induction Linac Systems Experiments (ILSE) [Fessenden, Nucl. Instrum. Methods Plasma Res. A 278, 13 (1989)] at LBL are described. Axially cold beams are observed to exhibit little or no root-mean-square emittance growth at midpulse in transiting a (sharp) bend. Axially hot beams, in contrast, do exhibit some emittance growth

  14. In-situ determination of energy species yields of intense particle beams

    Science.gov (United States)

    Kugel, H.W.; Kaita, R.

    1983-09-26

    Objects of the present invention are provided for a particle beam having a full energy component at least as great as 25 keV, which is directed onto a beamstop target, such that Rutherford backscattering, preferably near-surface backscattering occurs. The geometry, material composition and impurity concentration of the beam stop are predetermined, using any suitable conventional technique. The energy-yield characteristic response of backscattered particles is measured over a range of angles using a fast ion electrostatic analyzer having a microchannel plate array at its focal plane. The knee of the resulting yield curve, on a plot of yield versus energy, is analyzed to determine the energy species components of various beam particles having the same mass.

  15. Energy and time spreads of a particle beam used in APM technique

    International Nuclear Information System (INIS)

    A Monte Carlo code has been developed to simulate neutron and alpha production in the time correlated associated particle method (TCAPM). The atomic and molecular composition of the deuterium beam, tritium ratio in the target, slowing-down and straggling of deuterons as well as the angular dependence of emitted neutrons and alpha particles are both taken into account in these calculations. The following physical characteristics are obtained: mean energy of detected alpha particles and their spread, mean time of flight and its spread values for alpha particles, alpha and associated neutron spectra as well as neutron spatial cone distribution. (author). 11 refs, 10 figs, 4 tabs

  16. Monte Carlo N Particle code - Dose distribution of clinical electron beams in inhomogeneous phantoms

    OpenAIRE

    H A Nedaie; Mosleh-Shirazi, M. A.; Allahverdi, M.

    2013-01-01

    Electron dose distributions calculated using the currently available analytical methods can be associated with large uncertainties. The Monte Carlo method is the most accurate method for dose calculation in electron beams. Most of the clinical electron beam simulation studies have been performed using non- MCNP [Monte Carlo N Particle] codes. Given the differences between Monte Carlo codes, this work aims to evaluate the accuracy of MCNP4C-simulated electron dose distributions in a homogenous...

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

    OpenAIRE

    Schroeder, C. B.

    2011-01-01

    Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.

  18. Nonlinear δf Simulations of Collective Effects in Intense Charged Particle Beams

    International Nuclear Information System (INIS)

    A nonlinear delta(f) particle simulation method based on the Vlasov-Maxwell equations has been recently developed to study collective processes in high-intensity beams, where space-charge and magnetic self-field effects play a critical role in determining the nonlinear beam dynamics. Implemented in the Beam Equilibrium, Stability and Transport (BEST) code [H. Qin, R.C. Davidson, and W.W. Lee, Physical Review -- Special Topics on Accelerator and Beams 3 (2000) 084401; 3 (2000) 109901.], the nonlinear delta(f) method provides a low-noise and self-consistent tool for simulating collective interactions and nonlinear dynamics of high-intensity beams in modern and next-generation accelerators and storage rings, such as the Spallation Neutron Source and heavy ion fusion drivers. A wide range of linear eigenmodes of high-intensity charged-particle beams can be systematically studied using the BEST code. Simulation results for the electron-proton two-stream instability in the Proton Storage Ring experiment [R. Macek, et al., in Proc. of the Particle Accelerator Conference, Chicago, 2001 (IEEE, Piscataway, NJ, 2001), Vol. 1, p. 688.] at the Los Alamos National Laboratory agree well with experimental observations. Large-scale parallel simulations have also been carried out for the ion-electron two-stream instability in the very-high-intensity heavy ion beams envisioned for heavy ion fusion applications. In both cases, the simulation results indicate that the dominant two-stream instability has a dipole-mode (hose-like) structure and can be stabilized by a modest axial momentum spread of the beam particles

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

    OpenAIRE

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

    1998-01-01

    A recent proposal (see quant-ph/9803068) to simulate semiclassical corrections to classical dynamics by suitable classical stochastic fluctuations is applied to the specific instance of charged beam dynamics in particle accelerators. The resulting picture is that the collective beam dynamics, at the leading semiclassical order in Planck constant can be described by a particular diffusion process, the Nelson process, which is time-reversal invariant. Its diffusion coefficient $\\sqrt{N}\\lambda_...

  20. A fast wire scanner, used to measure the transverse density distribution of beams circulating in an accelerator or storage ring.

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Fast wire scanners are used to measure the transverse density distribution of beams circulating in an accelerator or storage ring. In order to minimize blow-up of the beam through multiple Coulomb scattering, the wires are very thin (in the version shown here it is actually a twisted strand of carbon fibres with a total diameter of about 25 microns) and are swept through the beam at high speed (a linear motor, not mounted here, accelerates the wires to up to 20 m/s). One measures either the secondary emission current from the wire, or the signal from a scintillator/photomultiplier combination downstream from the wire scanner receiving the shower from nuclear reactions of beam particles with the wire nuclei. There are four such fast wire scanners in the 26 GeV PS and eight in the 1.4 GeV Booster.

  1. Particle-beam accelerators for radiotherapy and radioisotopes

    International Nuclear Information System (INIS)

    The philosophy used in developing the new PIGMI technology was that the parameters chosen for physics research machines are not necessarily the right ones for a dedicated therapy or radioisotope machine. In particular, the beam current and energy can be optimized, and the design should emphasize minimum size, simplicity and reliability of operation, and economy in capital and operating costs. A major part of achieving these goals lay in raising the operating frequency and voltage gradient of the accelerator, which shrinks the diameter and length of the components. Several other technical innovations resulted in major system improvements. One of these is a radically new type of accelerator structure named the radio-frequency quadrupole (RFQ) accelerator. This allowed us to eliminate the large, complicated ion source used in previous ion accelerators, and to achieve a very high quality accelerated beam. Also, by using advanced permanent magnet materials to make the focusing elements, the system becomes much simpler. Other improvements have been made in all of the accelerator components and in the methods for operating them. These will be described, and design and costing information examples given for several possible therapy and radioisotope production machines

  2. Characterization of a radioactive {sup 11}C beam by means of the associated particle technique

    Energy Technology Data Exchange (ETDEWEB)

    Varela, A.; Policroniades, R.; Murillo, G.; Moreno, E. [ININ, Laboratorio del Acelerador Tandem, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Huerta, A.; Chavez, E.; Ortiz, M. E.; Barron, L.; Curiel, Q. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Aguilar, C.; Coello, E. A.; Juarez, M. A.; Martinez, J. N. [UNAM, Facultad de Ciencias, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-02-15

    This paper describes the results obtained for the production and characterization of a radioactive {sup 11}C beam, by means of the in flight technique and the tandem laboratory of the National Institute of Nuclear Research, Mexico. The {sup 11}C production technique described here, uses the well known associated particle technique with the reaction {sup 2}H({sup 10}B, {sup 11}C)n, in order to obtain a bi univocal correspondence between the radioactive {sup 11}C particles and the associated neutrons. A discussion concerning the possible use of this {sup 11}C beam in the study of the elastic scattering of protons is introduced. (Author)

  3. An alpha particle measurement system using an energetic neutral helium beam in ITER (invited).

    Science.gov (United States)

    Sasao, M; Kisaki, M; Kobuchi, T; Tsumori, K; Tanaka, N; Terai, K; Okamoto, A; Kitajima, S; Kaneko, O; Shinto, K; Wada, M

    2012-02-01

    An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He(+) ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He(+) ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application.

  4. Numerical Studies of Electromagnetic Instabilities in Intense Charged Particle Beams with Large Energy Anisotropy

    CERN Document Server

    Startsev, Edward; Lee, Wei-li

    2005-01-01

    In intense charged particle beams with large energy anisotropy, free energy is available to drive transverse electromagnetic Weibel-type instabilities. Such slow-wave transverse electromagnetic instabilities can be described by the so-called Darwin model, which neglects the fast-wave portion of the displacement current. The Weibel instability may also lead to an increase in the longitudinal velocity spread, which would make the focusing of the beam difficult and impose a limit on the minimum spot size achievable in heavy ion fusion experiments. This paper reports the results of recent numerical studies of the Weibel instability using the Beam Eigenmode And Spectra (bEASt) code for space-charge-dominated, low-emittance beams with large tune depression. To study the nonlinear stage of the instability, the Darwin model is being developed and incorporated into the Beam Equilibrium Stability and Transport(BEST) code.

  5. Particle beam technology for control of atomic-bonding state in materials

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Junzo [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    The atomic-bonding state in materials can be controlled through `kinetic bonding` process by energetic particle beams which have a sufficient atomic kinetic energy. In order to clarify the `kinetic bonding` process the negative-ion beam deposition is considered as an ideal method because the negative ion has no additional active energies. Sputter type heavy negative-ion sources can be used for this purpose. Carbon films prepared by carbon negative-ion beam deposition have a strong dependency of the film properties on ion beam kinetic energy and have a quite high thermal conductivity which is comparable to that of the IIb diamond at a kinetic energy of 50-100 eV/atom. It suggests that new or metastable materials could be formed through the `kinetic bonding` process. Negative-ion beams can also be used for ion implantation, in which charging problems are perfectly reduced. (author)

  6. Proton beam shaped by "particle lens" formed by laser-driven hot electrons

    Science.gov (United States)

    Zhai, S. H.; Shen, B. F.; Wang, W. P.; Zhang, H.; He, S. K.; Lu, F.; Zhang, F. Q.; Deng, Z. G.; Dong, K. G.; Wang, S. Y.; Zhou, K. N.; Xie, N.; Wang, X. D.; Zhang, L. G.; Huang, S.; Liu, H. J.; Zhao, Z. Q.; Gu, Y. Q.; Zhang, B. H.; Xu, Z. Z.

    2016-05-01

    Two-dimensional tailoring of a proton beam is realized by a "particle lens" in our experiment. A large quantity of electrons, generated by an intense femtosecond laser irradiating a polymer target, produces an electric field strong enough to change the trajectory and distribution of energetic protons flying through the electron area. The experiment shows that a strip pattern of the proton beam appears when hot electrons initially converge inside the plastic plate. Then the shape of the proton beam changes to a "fountain-like" pattern when these hot electrons diffuse after propagating a distance.

  7. A 128-channel picoammeter system and its application on charged particle beam current distribution measurements

    Science.gov (United States)

    Yu, Deyang; Liu, Junliang; Xue, Yingli; Zhang, Mingwu; Cai, Xiaohong; Hu, Jianjun; Dong, Jinmei; Li, Xin

    2015-11-01

    A 128-channel picoammeter system is constructed based on instrumentation amplifiers. Taking advantage of a high electric potential and narrow bandwidth in DC energetic charged beam measurements, a current resolution better than 5 fA can be achieved. Two sets of 128-channel strip electrodes are implemented on printed circuit boards and are employed for ion and electron beam current distribution measurements. Tests with 60 keV O3+ ions and 2 keV electrons show that it can provide exact boundaries when a positive charged particle beam current distribution is measured.

  8. Particle beam experiments for the analysis of reactive sputtering processes in metals and polymer surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; Arcos, Teresa de los; Benedikt, Jan; Keudell, Achim von [RD Plasmas with Complex Interactions, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum (Germany)

    2013-10-15

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions in reactive sputtering applications. Atom and ion sources are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions, and metal vapor. The heterogeneous surface processes are monitored in situ by means of a quartz crystal microbalance and Fourier transform infrared spectroscopy. Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma pre-treatment of polymers (PET, PP)

  9. BLOW-UP CRITERION OF SMOOTH SOLUTIONS TO THE MHD EQUATIONS IN BESOV SPACES

    Institute of Scientific and Technical Information of China (English)

    YUAN Baoquan

    2005-01-01

    In this paper we discuss the logarithmic Sobolev inequalities in Besov spaces,and show their applications to the blow-up criterion of smooth solutions to the incompressible magneto-hydrodynamics equations.

  10. On lower bounds for possible blow-up solutions to the periodic Navier-Stokes equation

    Energy Technology Data Exchange (ETDEWEB)

    Cortissoz, Jean C., E-mail: jcortiss@uniandes.edu.co; Montero, Julio A., E-mail: ja.montero907@uniandes.edu.co; Pinilla, Carlos E., E-mail: ce.pinilla108@uniandes.edu.co [Departamento de Matemáticas, Universidad de los Andes, Bogotá DC (Colombia)

    2014-03-15

    We show a new lower bound on the H{sup .3/2} (T{sup 3}) norm of a possible blow-up solution to the Navier-Stokes equation, and also comment on the extension of this result to the whole space. This estimate can be seen as a natural limiting result for Leray's blow-up estimates in L{sup p}(R{sup 3}), 3 < p < ∞. We also show a lower bound on the blow-up rate of a possible blow-up solution of the Navier-Stokes equation in H{sup .5/2} (T{sup 3}), and give the corresponding extension to the case of the whole space.

  11. Blow-up behavior of positive solutions for a chemical fuel ignition device model

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Yunfeng; Wu, Jianhua [College of Mathematics and Information Science, Shaanxi Normal University, Xi' an, Shaanxi 710062 (China); Xu, Hong-Kun [Department of Applied Mathematics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China)

    2014-04-15

    Blow-up behavior of positive solutions of a semi-linear parabolic system arising from thermal explosion, which subject to the homogenous Dirichlet boundary conditions, is investigated. In particular, sufficient conditions for the solutions to blow up are obtained.

  12. Finite time blowup of solutions to the nonlinear Schrödinger equation without gauge invariance

    Science.gov (United States)

    Fujiwara, Kazumasa; Ozawa, Tohru

    2016-08-01

    A lifespan estimate and a condition of the initial data for finite time blowup for the nonlinear Schrödinger equation are presented from a view point of ordinary differential equation (ODE) mechanism.

  13. Spinning and orbiting motion of particles in vortex beams with circular or radial polarizations.

    Science.gov (United States)

    Li, Manman; Yan, Shaohui; Yao, Baoli; Liang, Yansheng; Zhang, Peng

    2016-09-01

    Focusing fields of optical vortex (OV) beams with circular or radial polarizations carry both spin angular momentum (SAM) and orbital angular momentum (OAM), and can realize non-axial spinning and orbiting motion of absorptive particles. Using the T-matrix method, we evaluate the optical forces and torques exerted on micro-sized particles induced by the OV beams. Numerical results demonstrate that the particle is trapped on the circle of intensity maxima, and experiences a transverse spin torque along azimuthal direction, a longitudinal spin torque, and an orbital torque, respectively. The direction of spinning motion is not only related to the sign of topological charge of the OV beam, but also to the polarization state. However, the topological charge controls the direction of orbiting motion individually. Optically induced rotations of particles with varying sizes and absorptivity are investigated in OV beams with different topological charges and polarization states. These results may be exploited in practical optical manipulation, especially for optically induced rotations of micro-particles.

  14. Rf-synchronized imaging for particle and photon beam characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.

    1993-07-01

    The usefulness of imaging electro-optics for rf-driven accelerators can be enhanced by synchronizing the instruments to the system fundamental frequency or an appropriate subharmonic. This step allows one to obtain micropulse bunch length and phase during a series of linac bunches or storage ring passes. Several examples now exist of the use of synchroscan and dual-sweep streak cameras and/or image dissector tubes to access micropulse scale phenomena (10 to 30 ps) during linac and storage ring operations in the US, Japan, and Europe. As space permits, selections will be presented from the list of phase stability phenomena on photoelectric injectors, micropulse length during a macropulse, micropulse elongation effects, transverse Wakefield effects within a micropulse, and submicropulse phenomena on a stored beam. Potential applications to the subsystems of the Advanced Photon Source (APS) will be briefly addressed.

  15. Limiting profile of blow-up solutions for the Gross- Pitaevskii equation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper is concerned with the blow-up solutions of the Gross-Pitaevskii equation. Using the concentration compact principle and the variational characterization of the corresponding ground state, we obtain the limiting profile of blow-up solutions with critical mass in the corresponding weighted energy space. Moreover, we extend this result to small super-critical mass case by the variational methods and scaling technique.

  16. Periodic blow-up solutions and their limit forms for the generalized Camassa-Holm equation

    Institute of Scientific and Technical Information of China (English)

    Zhengrong Liu; Boling Guo

    2008-01-01

    In this paper, we consider the generalized Camassa-Holm equation ut + 2kux -uxxt + au2ux = 2uxuxx-uuxxxUnder substitution ζ = x - ct, some new explicit periodic wave solutions and their limit forms are presented through some special phase orbits. These periodic wave solutions tend to infinity on ζ - u plane periodically. Thus we call them periodic blow-up solutions. To our knowledge, such periodic blow-up solutions have not been found in any other equations.

  17. Blowup results for the KGS system with higher order Yukawa coupling

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Qi-Hong, E-mail: shiqh03@163.com [Department of Applied Mathematics, Lanzhou University of Technology, Lanzhou, Gansu 730050 (China); Li, Wan-Tong [School of Mathematics and Statistics, Lanzhou University, Lanzhou, Gansu 730000 (China); Wang, Shu [College of Applied Sciences, Beijing University of Technology, Beijing 100124 (China)

    2015-10-15

    In this paper, we investigate the Klein-Gordon-Schrödinger (KGS) system with higher order Yukawa coupling in spatial dimensions N ≥ 3. We establish a perturbed virial type identity and prove blowup results relied on Lyapunov functionals for KGS system with a negative energy level. Additionally, we give a result with respect to the blowup rate in finite time for the radial solution in 3 spatial dimensions.

  18. Fukushima plutonium effect and blow-up regimes in neutron-multiplying media

    CERN Document Server

    Rusov, V D; Vaschenko, V M; Linnik, E P; Zelentsova, T N; Beglaryan, M E; Chernegenko, S A; Kosenko, S I; Molchinikolov, P A; Smolyar, V P; Grechan, E V

    2012-01-01

    It is shown that the capture and fission cross-sections of 238U and 239Pu increase with temperature within 1000-3000K range, in contrast to those of 235U, that under certain conditions may lead to the so-called blow-up modes, stimulating the anomalous neutron flux and nuclear fuel temperature growth. Some features of the blow-up regimes in neutron-multiplying media are discussed.

  19. On the blow-up of four dimensional Ricci flow singularities

    CERN Document Server

    Máximo, Davi

    2012-01-01

    In this paper we prove a conjecture by Feldman-Ilmanen-Knopf in \\cite{FIK} that the gradient shrinking soliton metric they constructed on the tautological line bundle over $\\CP^1$ is the uniform limit of blow-ups of a type I Ricci flow singularity on a closed manifold. We use this result to show that limits of blow-ups of Ricci flow singularities on closed four dimensional manifolds do not necessarily have non-negative Ricci curvature.

  20. BPS relations from spectral problems and blowup equations

    CERN Document Server

    Grassi, Alba

    2016-01-01

    Recently an exact duality between topological string and the spectral theory of operators constructed from mirror curves to toric Calabi-Yau threefolds has been proposed. At the same time an exact quantization condition for the cluster integrable systems associated to these geometries has been conjectured. The consistency between the two approaches leads to an infinite set of constraints for the refined BPS invariants of the toric Calabi-Yau threefolds. We show that, for the Y^{N,m} geometries, these constraints can be derived from the K-theoretic blowup equations for SU(N) SYM with generic Chern-Simons invariant m. In particular this furnishes a proof of the BPS constraints in the case of m = 0.

  1. Global Dynamics, Blow-Up, and Bianchi Cosmology

    CERN Document Server

    Ben-Gal, Nitsan; Buchner, Johannes; Hell, Juliette; Karnauhova, Anna; Liebscher, Stefan; Rendall, Alan; Smith, Brian; Stuke, Hannes; Väth, Martin; Fiedler, Bernold

    2016-01-01

    Many central problems in geometry, topology, and mathematical physics lead to questions concerning the long-time dynamics of solutions to ordinary and partial differential equations. Examples range from the Einstein field equations of general relativity to quasilinear reaction-advection-diffusion equations of parabolic type. Specific questions concern the convergence to equilibria, the existence of periodic, homoclinic, and heteroclinic solutions, and the existence and geometric structure of global attractors. On the other hand, many solutions develop singularities in finite time. The singularities have to be analyzed in detail before attempting to extend solutions beyond their singularities, or to understand their geometry in conjunction with globally bounded solutions. In this context we have also aimed at global qualitative descriptions of blow-up and grow-up phenomena.

  2. Heavy Charged Particle Radiobiology: Using Enhanced Biological Effectiveness and Improved Beam Focusing to Advance Cancer Therapy

    OpenAIRE

    Allen, Christopher; Borak, Thomas B.; Tsujii, Hirohiko; Jac A Nickoloff

    2011-01-01

    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilitie...

  3. Stochastic collective dynamics of charged-particle beams in the stability regime.

    Science.gov (United States)

    Petroni, N C; De Martino, S; De Siena, S; Illuminati, F

    2001-01-01

    We introduce a description of the collective transverse dynamics of charged (proton) beams in the stability regime by suitable classical stochastic fluctuations. In this scheme, the collective beam dynamics is described by time-reversal invariant diffusion processes deduced by stochastic variational principles (Nelson processes). By general arguments, we show that the diffusion coefficient, expressed in units of length, is given by lambda(c)sqrt[N], where N is the number of particles in the beam and lambda(c) the Compton wavelength of a single constituent. This diffusion coefficient represents an effective unit of beam emittance. The hydrodynamic equations of the stochastic dynamics can be easily recast in the form of a Schrödinger equation, with the unit of emittance replacing the Planck action constant. This fact provides a natural connection to the so-called "quantum-like approaches" to beam dynamics. The transition probabilities associated to Nelson processes can be exploited to model evolutions suitable to control the transverse beam dynamics. In particular we show how to control, in the quadrupole approximation to the beam-field interaction, both the focusing and the transverse oscillations of the beam, either together or independently. PMID:11304370

  4. Beam-Beam Effects

    CERN Document Server

    Herr, W

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  5. Unsharp particle-wave duality in a photon split-beam experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mittelstaedt, P.; Prieur, A.; Schieder, R.

    1987-09-01

    In a quantum mechanical two-slit experiment one can observe a single photon simultaneously as particle (measuring the path) and as wave (measuring the interference pattern) if the path and the interference pattern are measured in the sense of unsharp observables. These theoretical predictions are confirmed by a photon split-beam experiment using a modified Mach-Zehnder interferometer.

  6. Scattering of Gaussian beam by a spherical particle with a spheroidal inclusion

    International Nuclear Information System (INIS)

    A generalized Lorenz-Mie theory framework (GLMT) is applied to the study of Gaussian beam scattering by a spherical particle with an embedded spheroid at the center. By virtue of a transformation between the spherical and spheroidal vector wave functions, a theoretical procedure is developed to deal with the boundary conditions. Numerical results of the normalized differential scattering cross section are presented.

  7. Relaxation Time of the Particle Beam with an Anisotropic Velocity Distribution

    Directory of Open Access Journals (Sweden)

    V.P. Vechirka

    2012-11-01

    Full Text Available The computer experiment for study of the relaxation time of the beam particles with an anisotropic velocity distribution is performed by the molecular dynamics. Obtained results agree with the characteristic times of thermal relaxation in plasma for the electronic coolers in modern storage rings.

  8. Charged particle's flux measurement from PMMA irradiated by 80 MeV/u carbon ion beam

    CERN Document Server

    Agodi, C; Bellini, F; Cirrone, G A P; Collamati, F; Cuttone, G; De Lucia, E; De Napoli, M; Di Domenico, A; Faccini, R; Ferroni, F; Fiore, S; Gauzzi, P; Iarocci, E; Marafini, M; Mattei, I; Muraro, S; Paoloni, A; Patera, V; Piersanti, L; Romano, F; Sarti, A; Sciubba, A; Vitale, E; Voena, C

    2012-01-01

    Hadrontherapy is an emerging technique in cancer therapy that uses beams of charged particles. To meet the improved capability of hadrontherapy in matching the dose release with the cancer position, new dose monitoring techniques need to be developed and introduced into clinical use. The measurement of the fluxes of the secondary particles produced by the hadron beam is of fundamental importance in the design of any dose monitoring device and is eagerly needed to tune Monte Carlo simulations. We report the measurements done with charged secondary particles produced from the interaction of a 80 MeV/u fully stripped carbon ion beam at the INFN Laboratori Nazionali del Sud, Catania, with a Poly-methyl methacrylate target. Charged secondary particles, produced at 90$\\degree$ with respect to the beam axis, have been tracked with a drift chamber, while their energy and time of flight has been measured by means of a LYSO scintillator. Secondary protons have been identified exploiting the energy and time of flight in...

  9. Analysis of the dynamic behavior of an intense charged particle beam using the semigroup approach

    Science.gov (United States)

    Stafford, M. A.

    1985-05-01

    Dynamic models of a charged particle beam subject to external electromagnetic fields are cast into the abstract Cauchy problem form. Various applications of intense charged particle beams, i.e., beams whose self electromagnetic fields are significant, might require, or be enhanced by, the use of dynamic control constructed from suitably processed measurements of the state of the beam. This research provides a mathematical foundation for future engineering development of estimation and control designs for such beams. Beginning with the Vlasov equation, successively simpler models of intense beams are presented, along with their corresponding assumptions. Expression of a model in abstract Cauchy problem form is useful in determining whether the model is well posed. Solutions of well-posed problems can be expressed in terms of a one-parameter semigroup of linear operators. (The state transition matrix for a system of linear, ordinary, first-order, constant coefficient differential equations is a special case of such a semigroup.) The semigroup point of view allows the application of the rapidly maturing modern control theory of infinite-dimensional systems. An appropriate underlying Banach space is identified for a simple, but non-trivial, single degree of freedom model (the electrostatic approximation model), and the associated one-parameter semigroup of linear operators is characterized.

  10. Analysis of the dynamic behavior of an intense charged particle beam using the semigroup approach

    International Nuclear Information System (INIS)

    Dynamic models of a charged particle beam subject to external electromagnetic fields are cast into the abstract Cauchy problem form. Various applications of intense charged particle beams, i.e., beams whose self electromagnetic fields are significant, might require, or be enhanced by, the use of dynamic control constructed from suitably processed measurements of the state of the beam. This research provides a mathematical foundation for future engineering development of estimation and control designs for such beams. Beginning with the Vlasov equation, successively simpler models of intense beams are presented, along with their corresponding assumptions. Expression of a model in abstract Cauchy problem form is useful in determining whether the model is well posed. Solutions of well-posed problems can be expressed in terms of a one-parameter semigroup of linear operators. The semigroup point of view allows the application of the rapidly maturing modern control theory of infinite dimensional system. An appropriate underlying Banach space is identified for a simple, but nontrivial, single degree of freedom model (the electrostatic approximation model), and the associated one-parameter semigroup of linear operators is characterized

  11. Damage evaluation in metal structures subjected to high energy deposition due to particle beams

    CERN Document Server

    Peroni, L; Dallocchio, A

    2011-01-01

    The unprecedented energy intensities of modern hadron accelerators yield special problems with the materials that are placed close to or into the high intensity beams. The energy stored in a single beam of LHC particle accelerator is equivalent to about 80 kg of TNT explosive, stored in a transverse beam area with a typical value of 0.2 mm×0.2 mm. The materials placed close to the beam are used at, or even beyond, their damage limits. However, it is very difficult to predict structural efficiency and robustness accurately: beam-induced damage for high energy and high intensity occurs in a regime where practical experience does not exist. The interaction between high energy particle beams and metals induces a sudden non uniform temperature increase. This provokes a dynamic response of the structure entailing thermal stress waves and thermally induced vibrations or even the failure of the component. This study is performed in order to estimate the damage on a copper component due to the impact with a 7 TeV pro...

  12. Nonlinear delta f Simulations of Collective Effects in Intense Charged Particle Beams

    CERN Document Server

    Hong Qi

    2003-01-01

    A nonlinear delta(f) particle simulation method based on the Vlasov-Maxwell equations has been recently developed to study collective processes in high-intensity beams, where space-charge and magnetic self-field effects play a critical role in determining the nonlinear beam dynamics. Implemented in the Beam Equilibrium, Stability and Transport (BEST) code [H. Qin, R.C. Davidson, and W.W. Lee, Physical Review -- Special Topics on Accelerator and Beams 3 (2000) 084401; 3 (2000) 109901.], the nonlinear delta(f) method provides a low-noise and self-consistent tool for simulating collective interactions and nonlinear dynamics of high-intensity beams in modern and next-generation accelerators and storage rings, such as the Spallation Neutron Source and heavy ion fusion drivers. A wide range of linear eigenmodes of high-intensity charged-particle beams can be systematically studied using the BEST code. Simulation results for the electron-proton two-stream instability in the Proton Storage Ring experiment [R. Macek, ...

  13. 100 years of elementary particles [Beam Line, vol. 27, number 1, Spring 1997

    International Nuclear Information System (INIS)

    This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe

  14. 100 years of elementary particles [Beam Line, vol. 27, issue 1, Spring 1997

    Energy Technology Data Exchange (ETDEWEB)

    Pais, Abraham; Weinberg, Steven; Quigg, Chris; Riordan, Michael; Panofsky, Wolfgang K.H.; Trimble, Virginia

    1997-04-01

    This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe.

  15. 100 years of Elementary Particles [Beam Line, vol. 27, issue 1, Spring 1997

    Science.gov (United States)

    Pais, Abraham; Weinberg, Steven; Quigg, Chris; Riordan, Michael; Panofsky, Wolfgang K. H.; Trimble, Virginia

    1997-04-01

    This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe.

  16. Particle beam extraction at the Orsay cryogenic coil cyclotron

    International Nuclear Information System (INIS)

    We are presenting the design and the performance of the single turn extraction in the Orsay cryogenic cyclotron. After a careful shaping of the average magnetic field in the extraction area for a representative set of particles, we get the various expected corresponding νsub(r) (νsub(s)) diagrams and then the corrected diagram of the kinetic energy per nucleon T at the exit vs Z/A. The study of the accelerated orbits till the entrance in the extraction devices shows the turn separation is sufficient to allow the insertion of an electrostatic septum and satisfying energies and RF phases are obtained. The designed extraction devices are successively: an electrostatic deflector, located in a hill, with an electric field 100 kV/cm, an iron free channel, located in the following hill, having to produce a field drop 0.25 T, some magnetostatic channels for radial focusing. A quick look at the technological features of the electromagnetic channel is given proving its possibility

  17. Mixed Diffusive-Convective Relaxation of a Warm Beam of Energetic Particles in Cold Plasma

    Directory of Open Access Journals (Sweden)

    Nakia Carlevaro

    2016-04-01

    Full Text Available This work addresses the features of fast particle transport in the bump-on-tail problem for varying the width of the fluctuation spectrum, in the view of possible applications to studies of energetic particle transport in fusion plasmas. Our analysis is built around the idea that strongly-shaped beams do not relax through diffusion only and that there exists an intermediate time scale where the relaxations are convective (ballistic-like. We cast this idea in the form of a self-consistent nonlinear dynamical model, which extends the classic equations of the quasi-linear theory to “broad” beams with internal structure. We also present numerical simulation results of the relaxation of a broad beam of energetic particles in cold plasma. These generally demonstrate the mixed diffusive-convective features of supra-thermal particle transport essentially depending on nonlinear wave-particle interactions and phase-space structures. Taking into account the modes of the stable linear spectrum is crucial for the self-consistent evolution of the distribution function and the fluctuation intensity spectrum.

  18. P.I.A.F.E. project: production of highly charged particles for radioactive ion beams

    International Nuclear Information System (INIS)

    The transformation of a mono-charged ion beam into a multicharged ion beam is an important problem in the projects of radioactive beams acceleration. This transformation must be performed with the best possible efficiency and in the shortest possible time to avoid the loss of particles by radioactive degenerescence. A ionization method using an electron cyclotron resonance (ECR) source is proposed. It consists in the fast capture by the ECR plasma of the radioactive elements injected inside this source in the form of a mono-charged ion beam. This method gives good results (2 to 6% efficiency to move from the 1+ to the 9+ charge state) for the ionization of alkaline elements, rare and metallic gases, with fast times of response allowing the ionization of radioactive products with a lifetime inferior to 1 s. (J.S.)

  19. Opening and construction of facilities in succession for particle beam therapy of cancer

    International Nuclear Information System (INIS)

    This feature article describes the current state of practical particle beam therapy of cancer, its future prospect, recent opening/construction of its facilities and manufacturers' view with following 9 topics presented by relevant experts. Gunma University (topic 1) started the carbon ion therapy from Mar., 2010, and has treated more than 100 cancer patients to aim the treatment of about 600 patients/year after several years. Fukui Prefectural Hospital Proton Therapy Center (topic 2) started from this March with proton beams for patients with its therapeutic standard, in cooperation with insurance companies and hotels for patients' convenience. Medipolis Proton Therapy and Research Center (Kagoshima Pref.) (topic 3) started this year with proton beams for 13 patients hitherto with reference protocol of Hyogo Ion Beam Medical Center. A new stereotactic irradiation system of proton beams for breast cancer has been developed. Construction of Saga Heavy Ion Medical Accelerator in Tosu (Saga Pref.) (topic 4) began this year to be completed in 2013. Aizawa Hospital (Nagano Pref.) (topic 5) plans to introduce the small-sized proton accelerator-gantry system (Sumitomo Heavy Ind., Ltd.) aiming the practice in 2013. Association for Nuclear Technology in Medicine (topic 6) reports the trends of current and future construction inside/outside Japan. Manufacturers comment their respective business: high-speed scanning irradiation system, next generation handling system of patient and particle beam therapy information system by Toshiba (topic 7); designation of the whole heavy ion beam therapy system (with NIRS), proton beam (as in topic 5) and system of BNCT (boron neutron-capture therapy) (Kyoto Univ.) by Sumitomo Heavy Ind., Ltd. (topic 8); and small-size proton therapeutic machine with 4D tracing capability for patient's movement (Hokkaido Univ.) and with spot-scanning irradiation technique by Hitachi (topic 9). (author)

  20. Modified convolution method to reconstruct particle hologram with an elliptical Gaussian beam illumination.

    Science.gov (United States)

    Wu, Xuecheng; Wu, Yingchun; Yang, Jing; Wang, Zhihua; Zhou, Binwu; Gréhan, Gérard; Cen, Kefa

    2013-05-20

    Application of the modified convolution method to reconstruct digital inline holography of particle illuminated by an elliptical Gaussian beam is investigated. Based on the analysis on the formation of particle hologram using the Collins formula, the convolution method is modified to compensate the astigmatism by adding two scaling factors. Both simulated and experimental holograms of transparent droplets and opaque particles are used to test the algorithm, and the reconstructed images are compared with that using FRFT reconstruction. Results show that the modified convolution method can accurately reconstruct the particle image. This method has an advantage that the reconstructed images in different depth positions have the same size and resolution with the hologram. This work shows that digital inline holography has great potential in particle diagnostics in curvature containers.

  1. Heavy charged particle radiobiology: using enhanced biological effectiveness and improved beam focusing to advance cancer therapy.

    Science.gov (United States)

    Allen, Christopher; Borak, Thomas B; Tsujii, Hirohiko; Nickoloff, Jac A

    2011-06-01

    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation.

  2. Heavy charged particle radiobiology: using enhanced biological effectiveness and improved beam focusing to advance cancer therapy.

    Science.gov (United States)

    Allen, Christopher; Borak, Thomas B; Tsujii, Hirohiko; Nickoloff, Jac A

    2011-06-01

    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation. PMID:21376738

  3. Stabilizing the intensity of a wave amplified by a beam of particles

    Energy Technology Data Exchange (ETDEWEB)

    Bachelard, R.; Chandre, C.; Leoncini, X.; Vittot, M. [Centre de Physique Theorique, Unite Mixte de Recherche, UMR 6207 du CNRS, et des universites Aix-Marseille-1, Aix-Marseille-2 et du Sud Toulon-Var, Lab. affilie a la FRUMAM (FR 2291), Lab. de Recherche Conventionne du CEA (DSM-06-35), CNRS Luminy, 13 - Marseille (France); Antoniazzi, A.; Fanelli, D. [Firenze Univ., Dipt. di Energetica and CSDC, INFN (Italy); Fanelli, D. [Karolinska Institute, Dept. of Cell and Molecular Biology, Stockholm (Sweden); Leoncini, X. [CNRS-Univ. de Provence, Centre de St Jerome, Physique des Interactions Ioniques et Moleculaires, 13 - Marseille (France)

    2007-04-15

    The intensity of an electromagnetic wave interacting self-consistently with a beam of charged particles as in a free electron laser, displays large oscillations due to an aggregate of particles, called the macro-particle. In this article, we propose a strategy to stabilize the intensity by re-shaping the macro-particle. This strategy involves the study of the linear stability (using the residue method) of selected periodic orbits of a mean-field model. As parameters of an additional perturbation are varied, bifurcations occur in the system which have drastic effect on the modification of the self-consistent dynamics, and in particular, of the macro-particle. We show how to obtain an appropriate tuning of the parameters which is able to strongly decrease the oscillations of the intensity without reducing its mean-value. (authors)

  4. Secondary particle acquisition system for the CERN beam wire scanners upgrade

    International Nuclear Information System (INIS)

    The increasing requirements of CERN experiments make essential the upgrade of beam instrumentation in general, and high accuracy beam profile monitors in particular. The CERN Beam Instrumentation Group has been working during the last years on the Wire Scanners upgrade. These systems cross a thin wire through a circulating beam, the resulting secondary particles produced from beam/wire interaction are detected to reconstruct the beam profile. For the new secondary shower acquisition system, it is necessary to perform very low noise measurements with high dynamic range coverage. The aim is to design a system without tuneable parameters and compatible for any beam wire scanner location at the CERN complex. Polycrystalline chemical vapour deposition diamond detectors (pCVD) are proposed as new detectors for this application because of their radiation hardness, fast response and linearity over a high dynamic range. For the detector readout, the acquisition electronics must be designed to exploit the detector capabilities and perform bunch by bunch measurements at 40MHz. This paper describes the design challenges of such a system, analysing different acquisition possibilities from the signal integrity point of view. The proposed system architecture is shown in detail and the development status presented

  5. Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma

    International Nuclear Information System (INIS)

    Neutralization and focusing of intense charged particle beam pulses by a background plasma forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating

  6. Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, I.D.; Davidson, R.C.; Dorf, M.A.; Startsev, E.A.; Sefkow, A.B; Friedman, A.F.; Lee, E.P.

    2009-09-03

    Neutralization and focusing of intense charged particle beam pulses by a background plasma forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating

  7. Controlled fabrication of nanopores using a direct focused ion beam approach with back face particle detection

    Science.gov (United States)

    Patterson, N.; Adams, D. P.; Hodges, V. C.; Vasile, M. J.; Michael, J. R.; Kotula, P. G.

    2008-06-01

    We report a direct, ion drilling technique that enables the reproducible fabrication and placement of nanopores in membranes of different thickness. Using a 30 keV focused Ga ion beam column combined with an in situ, back face, multi-channelplate particle detector, nanopores are sputtered in Si3N4 and W/Si3N4 to have diameters as small as 12 nm. Transmission electron microscopy shows that focused ion beam-drilled holes are near-conical with the diameter decreasing from entry to exit side. By monitoring the detector signal during ion exposure, the drilled hole width can be minimized such that the exit-side diameter is smaller than the full width at half-maximum of the nominally Gaussian-shaped incident beam. Judicious choice of the beam defining aperture combined with back face particle detection allows for reproducible exit-side hole diameters between 18 and 100 nm. The nanopore direct drilling technique does not require potentially damaging broad area exposure to tailor hole sizes. Moreover, this technique successfully achieves breakthrough despite the effects of varying membrane thickness, redeposition, polycrystalline grain structure, and slight ion beam current fluctuations.

  8. Controlled fabrication of nanopores using a direct focused ion beam approach with back face particle detection

    International Nuclear Information System (INIS)

    We report a direct, ion drilling technique that enables the reproducible fabrication and placement of nanopores in membranes of different thickness. Using a 30 keV focused Ga ion beam column combined with an in situ, back face, multi-channelplate particle detector, nanopores are sputtered in Si3N4 and W/Si3N4 to have diameters as small as 12 nm. Transmission electron microscopy shows that focused ion beam-drilled holes are near-conical with the diameter decreasing from entry to exit side. By monitoring the detector signal during ion exposure, the drilled hole width can be minimized such that the exit-side diameter is smaller than the full width at half-maximum of the nominally Gaussian-shaped incident beam. Judicious choice of the beam defining aperture combined with back face particle detection allows for reproducible exit-side hole diameters between 18 and 100 nm. The nanopore direct drilling technique does not require potentially damaging broad area exposure to tailor hole sizes. Moreover, this technique successfully achieves breakthrough despite the effects of varying membrane thickness, redeposition, polycrystalline grain structure, and slight ion beam current fluctuations

  9. Ion beam sputtering of Ag – Angular and energetic distributions of sputtered and scattered particles

    Energy Technology Data Exchange (ETDEWEB)

    Feder, René, E-mail: rene.feder@iom-leipzig.de; Bundesmann, Carsten; Neumann, Horst; Rauschenbach, Bernd

    2013-12-01

    Ion beam sputter deposition (IBD) provides intrinsic features which influence the properties of the growing film, because ion properties and geometrical process conditions generate different energy and spatial distribution of the sputtered and scattered particles. A vacuum deposition chamber is set up to measure the energy and spatial distribution of secondary particles produced by ion beam sputtering of different target materials under variation of geometrical parameters (incidence angle of primary ions and emission angle of secondary particles) and of primary ion beam parameters (ion species and energies). A representative set of Ag thin films is deposited arranged on a substrate holder equatorial to the Ag target in steps of 10° and characterized concerning their film thickness by profilometry to determine the angular distribution of the sputtered particles. The film thickness distributions show a tilted, cosine-like shape and a shifting of the maximum position depending on the primary particle energy and incidence angle of the primary ions. The energy distributions of sputtered and scattered ions and of sputtered neutrals are measured with an energy-selective mass spectrometer. The average energy of the sputtered ions increases with increasing emission angle and also increases with increasing incidence angle of the primary ions. In contrast, the average energy of the sputtered ions is nearly unaffected by the primary particle energy and particle species. The energy distribution of the scattered Ar ions reveals high energetic maxima which shift with increasing emission angle to higher energies. These maxima are not observed for Xe bombardment. The total energies of sputtered and scattered ions show significant differences between the two bombarding species. The maximum of the energy distribution of sputtered Ag neutrals is used to conclude on the surface binding energy of Ag (2.72 eV). All experimental data are compared with Monte Carlo simulations done with

  10. Cylindrical particle manipulation and negative spinning using a nonparaxial Hermite-Gaussian light-sheet beam

    Science.gov (United States)

    Mitri, F. G.

    2016-10-01

    Based on the angular spectrum decomposition method (ASDM), a nonparaxial solution for the Hermite-Gaussian (HG m ) light-sheet beam of any order m is derived. The beam-shape coefficients (BSCs) are expressed in a compact form and computed using the standard Simpson’s rule for numerical integration. Subsequently, the analysis is extended to evaluate the longitudinal and transverse radiation forces as well as the spin torque on an absorptive dielectric cylindrical particle in 2D without any restriction to a specific range of frequencies. The dynamics of the cylindrical particle are also examined based on Newton’s second law of motion. The numerical results show that a Rayleigh or Mie cylindrical particle can be trapped, pulled or propelled in the optical field depending on its initial position in the cross-sectional plane of the HG m light-sheet. Moreover, negative or positive axial spin torques can arise depending on the choice of the non-dimensional size parameter ka (where k is the wavenumber and a is the radius of the cylinder) and the location of the absorptive cylinder in the beam. This means that the HG m light-sheet beam can induce clockwise or anti-clockwise rotations depending on its shift from the center of the cylinder. In addition, individual vortex behavior can arise in the cross-sectional plane of wave propagation. The present analysis presents an analytical model to predict the optical radiation forces and torque induced by a HG m light-sheet beam on an absorptive cylinder for applications in optical light-sheet tweezers, optical micro-machines, particle manipulation and opto-fluidics to name a few areas of research.

  11. Nonlinear Theory in the Blowout Regime for Both Particle Beam and Laser Drivers

    CERN Document Server

    Lu, Wei; Huang Cheng Kun; Katsouleas, Thomas C; Mori, Warren; Shih Yu Tsung, Frank; Silva, Luis O; Tzoufras, Michail; Zhou, Miaomiao

    2005-01-01

    Recent progress in both PWFA and LWFA has confirmed the promising characteristics of the blowout regime. So it is worthwhile to understand the wake excitation process and other relevant issues (e.g. self trapping mechanism, laser self guiding, scaling laws) in this regime. Because the plasma electrons always cross each other in the blowout regime, it is not possible to use a fluid model. Instead, we use a particle picture. Based on the analysis of the innermost particle trajectory, we have developed a self-consistent theory for this regime. For particle beam drivers, we explained why linear theory can be a good approximation in the weakly nonlinear blowout regime and also obtained formulas to predict the wake amplitude. In the strongly nonlinear blowout regime (relativistic or ultra-relativistic), the theory can predict the wake structures and amplitudes in terms of the particle beam or laser pulse intensity. The theory also provides a basis for a beam loading theory in the blowout regime as well a basis for ...

  12. EFFECT OF PARTICLE SIZE AND PACKING RATIO OF PID ON VIBRATION AMPLITUDE OF BEAM

    Directory of Open Access Journals (Sweden)

    P.S. Kachare

    2013-06-01

    Full Text Available Everything in the universe that has mass possesses stiffness and intrinsic damping. Owing to the stiffness property, mass will vibrate when excited and its intrinsic damping property will act to stop the vibration. The particle impact damper (PID is a very interesting damper that affects impact and friction effects of particles by means of energy dissipation. PID is a means for achieving high structural damping by using a particle-filled enclosure attached to a structure. The particles absorb the kinetic energy of the structure and convert it into heat through inelastic collisions between the particles themselves and between the particles and the walls of the enclosure. In this work, PID is measured for a cantilever mild steel beam with an enclosure attached to its free end; copper particles are used in this study. The PID is found to be highly nonlinear. The most useful observation is that for a very small weight penalty (about 7% to 8 %, the maximum damped amplitude of vibration at resonance with a PID, is about 9 to 10 times smaller than that without a PID. It is for more than that of with only intrinsic material damping of a majority of structural metals. A satisfactory comparison of damping with and without particles through experimentation is observed. The effect of the size of the particles on the damping performance of the beam and the effective packing ratio can be identified. It is also shown that as the packing ratio changes, the contributions of the phenomena of impact and friction towards damping also change. It is encouraging that despite its deceptive simplicity, the model captures the essential physics of PID.

  13. Ultra-fast detection of relativistic charged particle beam bunches using optical techniques

    Science.gov (United States)

    Nikas, Dimitrios S.

    The use of light as a carrier of information has been the subject of discussion for many scientific papers. This approach has some unique features which distinguish it from conventional electronics. These are realized in applications like telecommunications where the use of optical fibers and Electro-Optic sampling is the industry standard. Electro-Optic sampling employs the "Pockels" or "Electro-Optic" effect. Pockels discovered that an electric field applied to some crystals changes the birefringence properties of the crystal, and hence the polarization of light that propagates through it. By placing the crystal between crossed polarizers, the transmitted light intensity changes as a function of the applied field. We made the first Electro-Optical (EO) detection of a relativistic charged particle beam, applying its Lorentz contracted electric field on an EO LiNbO 3 crystal. The resulted intensity modulation was initially reconstructed using a fast photodiode and a digital oscilloscope. The signal rise time was bandwidth limited (˜90ps) from the electronics used and a series of tests to establish our signal EO nature was performed. In particular, the amplitude of the EO modulation was found to increase linearly with the charge of the particle beam and decrease with the optical beam path distance from the charged particle beam. Also the signal polarity changed sign when the direction of the applied electric field was reversed. Next an optimized (for maximum modulation), zero bias, EO modulator was constructed for use with the limited dynamic range of the Streak Camera for the first non destructive, completely optical, detection of a charged particle beam. The observed signal may be an image of unexpected piezoelectrically generated sound waves that propagate at the X-axis of the LiNbO3 crystal. In such a case, sound waves generated in the surface as well as inside the crystal, change the index of refraction of the crystal through the photoelastic effect and as a

  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. Self-similarity of negative particle production from the Beam Energy Scan Program at STAR

    CERN Document Server

    Tokarev, M V

    2015-01-01

    We present the spectra of negative charged particle production in Au+Au collisions from STAR for the first phase of the RHIC Beam Energy Scan Program measured over a wide range of collision energy sqrt s{NN}=7.7-200 GeV, and transverse momentum of produced particle in different centralities at |eta|<0.5. The spectra demonstrate strong dependence on collision energy which enhances with pT. An indication of self-similarity of negative charged particle production in Au+Au collisions is found. The constituent energy loss as a function of energy and centrality of collisions and transverse momentum of inclusive particle was estimated in the $z$-scaling approach. The energy dependence of the model parameters - the fractal and fragmentation dimensions and "specific heat", was studied.

  16. Gaussian Wave formalism model for propagation of charged-particle beam through a first-order optical systems

    Institute of Scientific and Technical Information of China (English)

    Chen Bao-Xin

    2006-01-01

    An elliptical Gaussian wave formalism model of a charged-particle beam is proposed by analogy with an elliptical Gaussian light beam.In the paraxial approximation.the charged-particle beam can be described as a whole by a complex radius of curvature in the real space domains.Therefore,the propagation and transform of charged-particle beam passing through a first-order optical system is represented by the ABCD-like law.As an example of the application of this model,the relation between the beam waist and the minimum beam spot at a fixed target is discussed.The result.well matches that from conventional phase space model,and proves that the Gaussian wave formalism model is highly effective and reasonable.

  17. Perturbational blowup solutions to the compressible 1-dimensional Euler equations

    Energy Technology Data Exchange (ETDEWEB)

    Yuen, Manwai, E-mail: nevetsyuen@hotmail.com [Department of Applied Mathematics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2011-10-24

    We construct non-radially symmetry solutions for the compressible 1-dimensional adiabatic Euler equations in this Letter. In detail, we perturb the linear velocity with a drifting term: (1)u=c(t)x+b(t), to seek new solutions. Then, we transform the problem into the analysis of ordinary differential equations. By investigating the corresponding ordinary differential equations, a new class of blowup or global solutions can be given. Here, our constructed solutions can provide the mathematical explanations for the drifting phenomena of some propagation wave like Tsunamis. And when we adopt the Galilean-like transformation to a drifting frame, the constructed solutions are self-similar. -- Highlights: → We construct non-radially symmetry solutions for the 1-dimensional Euler equations. → We perturb the linear velocity with a drifting term to seek new solutions. → We transform the Euler system into the ordinary differential equations analysis. → The solutions model the drifting phenomena of some propagation wave like Tsunamis. → Under the Galilean-like transformation, the constructed solutions are self-similar.

  18. Measurement of charged particle yields from therapeutic beams in view of the design of an innovative hadrontherapy dose monitor

    Science.gov (United States)

    Battistoni, G.; Bellini, F.; Bini, F.; Collamati, F.; Collini, F.; De Lucia, E.; Durante, M.; Faccini, R.; Ferroni, F.; Frallicciardi, P. M.; La Tessa, C.; Marafini, M.; Mattei, I.; Miraglia, F.; Morganti, S.; Ortega, P. G.; Patera, V.; Piersanti, L.; Pinci, D.; Russomando, A.; Sarti, A.; Schuy, C.; Sciubba, A.; Senzacqua, M.; Solfaroli Camillocci, E.; Vanstalle, M.; Voena, C.

    2015-02-01

    Particle Therapy (PT) is an emerging technique, which makes use of charged particles to efficiently cure different kinds of solid tumors. The high precision in the hadrons dose deposition requires an accurate monitoring to prevent the risk of under-dosage of the cancer region or of over-dosage of healthy tissues. Monitoring techniques are currently being developed and are based on the detection of particles produced by the beam interaction into the target, in particular: charged particles, result of target and/or projectile fragmentation, prompt photons coming from nucleus de-excitation and back-to-back γ s, produced in the positron annihilation from β + emitters created in the beam interaction with the target. It has been showed that the hadron beam dose release peak can be spatially correlated with the emission pattern of these secondary particles. Here we report about secondary particles production (charged fragments and prompt γ s) performed at different beam and energies that have a particular relevance for PT applications: 12C beam of 80 MeV/u at LNS, 12C beam 220 MeV/u at GSI, and 12C, 4He, 16O beams with energy in the 50-300 MeV/u range at HIT. Finally, a project for a multimodal dose-monitor device exploiting the prompt photons and charged particles emission will be presented.

  19. New Density Estimation Methods for Charged Particle Beams With Applications to Microbunching Instability

    Energy Technology Data Exchange (ETDEWEB)

    Balsa Terzic, Gabriele Bassi

    2011-07-01

    In this paper we discuss representations of charge particle densities in particle-in-cell (PIC) simulations, analyze the sources and profiles of the intrinsic numerical noise, and present efficient methods for their removal. We devise two alternative estimation methods for charged particle distribution which represent significant improvement over the Monte Carlo cosine expansion used in the 2d code of Bassi, designed to simulate coherent synchrotron radiation (CSR) in charged particle beams. The improvement is achieved by employing an alternative beam density estimation to the Monte Carlo cosine expansion. The representation is first binned onto a finite grid, after which two grid-based methods are employed to approximate particle distributions: (i) truncated fast cosine transform (TFCT); and (ii) thresholded wavelet transform (TWT). We demonstrate that these alternative methods represent a staggering upgrade over the original Monte Carlo cosine expansion in terms of efficiency, while the TWT approximation also provides an appreciable improvement in accuracy. The improvement in accuracy comes from a judicious removal of the numerical noise enabled by the wavelet formulation. The TWT method is then integrated into Bassi's CSR code, and benchmarked against the original version. We show that the new density estimation method provides a superior performance in terms of efficiency and spatial resolution, thus enabling high-fidelity simulations of CSR effects, including microbunching instability.

  20. Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

    CERN Document Server

    Baszczyk, M K; Calabrese, R.; Cardinale, R.; Carniti, P.; Cassina, L.; Cavallero, G.; Cojocariu, L.; Cotta Ramusino, A.; D'Ambrosio, C.; Dorosz, P.A.; Maino, M.; Malaguti, R.; Matteuzzi, C.; McCann, M.; Morris, A.; Muheim, F.; Papanestis, A.; Pessina, G.; Easo, S.; Eisenhardt, S.; Fiorini, M.; Frei, C.; Gambetta, S.; Gibson, V.; Gotti, C.; Harnew, N.; He, J.; Kucewicz, W.; Maciuc, F.; Keizer, F.; Petrolini, A.; Piedigrossi, D.; Pistone, A.; Placinta, V.M.; Sigurdsson, S.; Simi, G.; Smith, J.; Spradlin, P.; Tomassetti, L.; Wotton, S.A.

    2016-01-01

    The LHCb detector will be upgraded to make more efficient use of the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov detectors are key components of the LHCb detector for particle identification. In this paper we describe the setup and the results of tests in a charged particle beam, carried out to assess prototypes of the upgraded opto-electronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

  1. Tests of the photon detection chain for the LHCb RICH Upgrade in a particle beam

    CERN Document Server

    Cardinale, Roberta

    2016-01-01

    The LHCb detector will be upgraded to use the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov (RICH) detectors are one of the key components of the LHCb detector for particle identification. In this paper, we describe the setup and the results of the first tests in a particle beam carried out to assess prototypes of the upgraded optoelectronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

  2. Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

    CERN Document Server

    Baszczyk, Mateusz Karol; Calabrese, Roberto; Cardinale, Roberta; Carniti, Paolo; Cassina, Lorenzo; Cavallero, Giovanni; Cojocariu, Lucian Nicolae; Cotta Ramusino, Angelo; D'Ambrosio, Carmelo; Dorosz, Piotr Andrzej; Easo, Sajan; Eisenhardt, Stephan; Fiorini, Massimiliano; Frei, Christoph; Gambetta, Silvia; Gibson, Valerie; Gotti, Claudio; Harnew, Neville; He, Jibo; Keizer, Floris; Kucewicz, Wojciech; Maciuc, Florin; Maino, Matteo; Malaguti, Roberto; Matteuzzi, Clara; Mccann, Michael Andrew; Morris, Adam; Muheim, Franz; Papanestis, Antonis; Pessina, Gianluigi; Petrolini, Alessandro; Piedigrossi, Didier; Pistone, Alessandro; Placinta, Vlad-Mihai; Sigurdsson, Saevar; Simi, Gabriele; Smith, Jackson William; Spradlin, Patrick; Tomassetti, Luca; Wotton, Stephen

    2016-01-01

    The LHCb detector will be upgraded to use the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov (RICH) detectors are one of the key components of the LHCb detector for particle identification. In this paper, we describe the setup and the results of the first tests in a particle beam carried out to assess prototypes of the upgraded optoelectronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

  3. Parallelisation of PyHEADTAIL, a Collective Beam Dynamics Code for Particle Accelerator Physics

    CERN Document Server

    Oeftiger, Adrian

    2016-01-01

    The longitudinal tracking engine of the particle accelerator simulation application PyHEADTAIL shows a heavy potential for parallelisation. For basic beam circulation, the tracking functionality with the leap-frog algorithm is extracted and compared between a sequential C and a concurrent CUDA C API implementation for 1 million revolutions. Including the sequential data I/O in both versions, a pure speedup of up to S = 100 is observed which is in the order of magnitude of what is expected from Amdahl's law. From O(100) macro-particles on the overhead of initialising the GPU CUDA device appears outweighed by the concurrent computations on the 448 available CUDA cores.

  4. Search for eV (pseudo)scalar penetrating particles in the SPS neutrino beam

    OpenAIRE

    Astier, P.; Autiero, D.; Baldisseri, A.; Baldo-Ceolin, M.; Ballocchi, G.; Banner, M.; Bassompierre, G.; Benslama, K.; Besson, N.; Bird, I.; Blumenfeld, B.; Bobisut, F.; Bouchez, J.; Boyd, S; Bueno, A.

    2000-01-01

    We carried out a model-independent search for light scalar or pseudoscalar particles $a$'s (an example of which is the axion) that couple to two photons by using a photon-regeneration method at high energies allowing a substantial increase in the sensitivity to $eV$ masses.\\ The experimental set-up is based on elements of the CERN West Area Neutrino Facility (WANF) beam line and theNOMAD neutrino detector.\\ The new particles, if they exist, could be produced through the Primakoff effect in in...

  5. Search for eV (pseudo)scalar penetrating particles in the SPS neutrino beam

    OpenAIRE

    NOMAD Collaboration; Astier, P.; Cervera Villanueva, Anselmo; Gómez Cadenas, Juan José

    2000-01-01

    We carried out a model-independent search for light scalar or pseudoscalar particles a's (an example of which is the axion) that couple to two photons by using a photon-regeneration method at high energies allowing a substantial increase in the sensitivity to eV masses.\\ The experimental set-up is based on elements of the CERN West Area Neutrino Facility (WANF) beam line and theNOMAD neutrino detector.\\ The new particles, if they exist, could be produced through the Primakoff effect in intera...

  6. Temporal behavior of neutral particle fluxes in TFTR (Tokamak Fusion Test Reactor) neutral beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Gammel, G.M.; Roquemore, A.L.; Grisham, L.R.; Kugel, H.W.; Medley, S.S.; O' Connor, T.E.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1989-09-01

    Data from an E {parallel} B charge exchange neutral analyzer (CENA), which views down the axis of a neutral beamline through an aperture in the target chamber calorimeter of the TFTR neutral beam test facility, exhibit two curious effects. First, there is a turn-on transient lasting tens of milliseconds having a magnitude up to three times that of the steady-state level. Second, there is a 720 Hz, up to 20% peak-to-peak fluctuation persisting the entire pulse duration. The turn-on transient occurs as the neutralizer/ion source system reaches a new pressure equilibrium following the effective ion source gas throughput reduction by particle removal as ion beam. Widths of the transient are a function of the gas throughput into the ion source, decreasing as the gas supply rate is reduced. Heating of the neutalizer gas by the beam is assumed responsible, with gas temperature increasing as gas supply rate is decreased. At low gas supply rates, the transient is primarliy due to dynamic changes in the neutralizer line density and/or beam species composition. Light emission from the drift duct corroborate the CENA data. At high gas supply rates, dynamic changes in component divergence and/or spatial profiles of the source plasma are necessary to explain the observations. The 720 Hz fluctuation is attributed to a 3% peak-to-peak ripple of 720 Hz on the arc power supply amplified by the quadratic relationship between beam divergence and beam current. Tight collimation by CENA apertures cause it to accept a very small part of the ion source's velocity space, producing a signal linearly proportional to beam divergence. Estimated fluctuations in the peak power density delivered to the plasma under these conditions are a modest 3--8% peak to peak. The efffects of both phenomena on the injected neutral beam can be ameliorated by careful operion of the ion sources. 21 refs., 11 figs., 2 tabs.

  7. Particle in cell simulation of laser-accelerated proton beams for radiation therapy

    International Nuclear Information System (INIS)

    In this article we present the results of particle in cell (PIC) simulations of laser plasma interaction for proton acceleration for radiation therapy treatments. We show that under optimal interaction conditions protons can be accelerated up to relativistic energies of 300 MeV by a petawatt laser field. The proton acceleration is due to the dragging Coulomb force arising from charge separation induced by the ponderomotive pressure (light pressure) of high-intensity laser. The proton energy and phase space distribution functions obtained from the PIC simulations are used in the calculations of dose distributions using the GEANT Monte Carlo simulation code. Because of the broad energy and angular spectra of the protons, a compact particle selection and beam collimation system will be needed to generate small beams of polyenergetic protons for intensity modulated proton therapy

  8. Diffraction Radiation Diagnostics for Moderate to High Energy Charged Particle Beams

    CERN Document Server

    Fiorito, R B

    2001-01-01

    Diffraction radiation (DR) is produced when a charged particle passes throughan aperture or near a discontinuity in the media in which it is traveling. DRis closely related to transition radiation (TR), which is produced when acharged particle traverses the boundary between media with different dielectricconstants. In contrast to TR, which is now extensively used for beam diagnosticpurposes, the potential of DR as a non-interceptive, multi-parameter beamdiagnostic remains largely undeveloped. For diagnostic measurements it isuseful to observe backward reflected DR from an circular aperture or slitinclined with respect to the beam velocity. However, up to now, well foundedequations for the spectral-angular intensities of backward DR from suchapertures have not been available. We present a new derivation of the spectralangular intensity of backward DR produced from an inclined slit for twoorientations of the slit axis, i.e. perpendicular and parallel to the plane ofincidence. Our mathematical approach is genera...

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

    CERN Document Server

    Hawkes, Peter W

    2011-01-01

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

  10. BLOW-UP RESULTS AND ASYMPTOTIC BEHAVIOR OF THE EMDEN-FOWLER EQUATION u"=|u|p

    Institute of Scientific and Technical Information of China (English)

    Li Mengrong

    2007-01-01

    In this article the author works with the ordinary differential equation u" =|u|p for some p > 0 and obtains some interesting phenomena concerning blow-up, blow-up rate, life-span, stability, instability, zeros and critical points of solutions to this equation.

  11. A BLOW-UP CRITERION FOR 3-D NON-RESISTIVE COMPRESSIBLE HEAT-CONDUCTIVE MAGNETOHYDRODYNAMIC EQUATIONS WITH INITIAL VACUUM

    Institute of Scientific and Technical Information of China (English)

    Xu Xinying

    2012-01-01

    In this paper; we prove a blow-up criterion of strong solutions to the 3-D viscous and non-resistive magnetohydrodynamic equations for compressible heat-conducting flows with initial vacuum.This blow-up criterion depends only on the gradient of velocity and the temperature,which is similar to the one for compressible Navier-Stokes equations.

  12. Particle manipulation beyond the diffraction limit using structured super-oscillating light beams

    CERN Document Server

    Singh, Brijesh Kumar; Roichman, Yael; Arie, Ady

    2016-01-01

    The diffraction limited resolution of light focused by a lens was derived in 1873 by Ernst Abbe. Later in 1952, a method to reach sub-diffraction light spots was proposed by modulating the wavefront of the focused beam. In a related development, super-oscillating functions, i.e. band limited functions that locally oscillate faster than their highest Fourier component, were introduced and experimentally applied for super-resolution microscopy. Up till now, only simple Gaussian-like sub-diffraction spots were used. Here we show that the amplitude and phase profile of these sub-diffraction spots can be arbitrarily controlled. In particular we utilize Hermite-Gauss, Laguerre-Gauss and Airy functions to structure super-oscillating beams with sub-diffraction lobes. These structured beams are then used for high resolution trapping and manipulation of nanometer-sized particles. The trapping potential provides unprecedented localization accuracy and stiffness, significantly exceeding those provided by standard diffrac...

  13. High-sensitive remote diagnostics of the accelerated particles' beam cross section

    International Nuclear Information System (INIS)

    The gauge for remote monitoring of the density distribution of accelerated particles' beam over cross section is based on the analysis spatial distribution of residual gas ionization products. With the transverse homogeneous electric field the released charges are transported through narrow slot behind which they are analyzed over energy with the electric field. Then they are registered by the open electron-optical converter with micro-channel-plate amplifier. The image of the beam distribution over cross section from the electron-optical converter screen is read out by TV-camera for representation on monitor. The detector was tested on cyclotrons at IAE (Moscow), INP (Kiev) and INP (Prague). The threshold sensitivity on the proton beam with the energy 30 MeV 10-8 A

  14. Beam-splitting code for light scattering by ice crystal particles within geometric-optics approximation

    Science.gov (United States)

    Konoshonkin, Alexander V.; Kustova, Natalia V.; Borovoi, Anatoli G.

    2015-10-01

    The open-source beam-splitting code is described which implements the geometric-optics approximation to light scattering by convex faceted particles. This code is written in C++ as a library which can be easy applied to a particular light scattering problem. The code uses only standard components, that makes it to be a cross-platform solution and provides its compatibility to popular Integrated Development Environments (IDE's). The included example of solving the light scattering by a randomly oriented ice crystal is written using Qt 5.1, consequently it is a cross-platform solution, too. Both physical and computational aspects of the beam-splitting algorithm are discussed. Computational speed of the beam-splitting code is obviously higher compared to the conventional ray-tracing codes. A comparison of the phase matrix as computed by our code with the ray-tracing code by A. Macke shows excellent agreement.

  15. Characterisation of Medipix3 Silicon Detectors in a Charged-Particle Beam

    CERN Document Server

    Carvalho Akiba, Kazu; Aoude, Jadallah; van Beuzekom, Martinus; Buytaert, Jan; Collins, Paula; Dosil Suarez, Alvaro; Dumps, Raphael; Gallas Torreira, Abraham Antonio; Hombach, Christoph; Hynds, Daniel; John, Malcolm; Leflat, Alexander; Li, Yiming; Perez Trigo, Eliseo; Plackett, Richard; Reid, M; Rodriguez Perez, Pablo; Schindler, Heinrich; Tsopelas, Panagiotis; Vazquez Sierra, Carlos; Velthuis, Johannes; Wysokinski, Michal Adam

    2016-01-01

    While designed primarily for X-ray imaging applications, the Medipix3 ASIC can also be used for charged-particle tracking. In this work, results from a beam test at the CERN SPS with irradiated and non-irradiated sensors are presented and shown to be in agreement with simulation, demonstrating the suitability of the Medipix3 ASIC as a tool for characterising pixel sensors.

  16. A Hybrid Particle Swarm Optimization (PSO)-Simplex Algorithm for Damage Identification of Delaminated Beams

    OpenAIRE

    Xiangdong Qian; Maosen Cao; Zhongqing Su; Jiangang Chen

    2012-01-01

    Delamination is a type of representative damage in composite structures, severely degrading structural integrity and reliability. The identification of delamination is commonly treated as an issue of nondestructive testing. Differing from existing studies, a hybrid optimization algorithm (HOA), combining particle swarm optimization (PSO) with simplex method (SM), is proposed to identify delamination in laminated beams. The objective function of the optimization problem is created using delami...

  17. Heat transfer phenomena in gas protected particle beam fusion reactor cavities

    International Nuclear Information System (INIS)

    The behavior of the fireball produced in particle beam fusion reactor cavities as the cavity gas near the target absorbs the X-rays and ionic debris emanating from the microexplosion is examined. Thermal response of the first wall to the radiative heat flux from the gas is examined parametrically. Criteria for the suitability of different cavity fill gases based on their ability to protect the first wall from excessive surface heating and ablation are discussed. 9 refs

  18. Automatic calibration and signal switching system for the particle beam fusion research data acquisition facility

    International Nuclear Information System (INIS)

    This report describes both the hardware and software components of an automatic calibration and signal system (Autocal) for the data acquisition system for the Sandia particle beam fusion research accelerators Hydra, Proto I, and Proto II. The Autocal hardware consists of off-the-shelf commercial equipment. The various hardware components, special modifications and overall system configuration are described. Special software has been developed to support the Autocal hardware. Software operation and maintenance are described

  19. Production of α-particle emitting 211At using 45 MeV α-beam

    Science.gov (United States)

    Kim, Gyehong; Chun, Kwonsoo; Park, Sung Ho; Kim, Byungil

    2014-06-01

    Among the α-particle emitting radionuclides, 211At is considered to be a promising radionuclide for targeted cancer therapy due to its decay properties. The range of alpha particles produced by the decay of 211At are less than 70 µm in water with a linear energy transfer between 100 and 130 keV µm-1, which are about the maximum relative biological effectiveness for heavy ions. It is important to note that at the present time, only a few of cyclotrons routinely produce 211At. The direct production method is based on the nuclear reactions 209Bi(α,2n)211At. Production of the radionuclide 211At was carried out using the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). To ensure high beam current, the α-beam was extracted with an initial energy of 45 MeV, which was degraded to obtain the appropriate α-beam energy. The calculations of beam energy degradation were performed utilizing the MCNPX. Alumina-baked targets were prepared by heating the bismuth metal powder onto a circular cavity in a furnace. When using an Eα, av of 29.17 MeV, the very small contribution of 210At confirms the right choice of the irradiation energy to obtain a pure production of 211At isotope.

  20. Mixed diffusive-convective relaxation of a broad beam of energetic particles in cold plasma

    CERN Document Server

    Carlevaro, Nakia; Falessi, Matteo V; Montani, Giovanni; Terzani, Davide; Zonca, Fulvio

    2015-01-01

    We revisit the applications of quasi-linear theory as a paradigmatic model for weak plasma turbulence and the associated bump-on-tail problem. The work, presented here, is built around the idea that large-amplitude or strongly shaped beams do not relax through diffusion only and that there exists an intermediate time scale where the relaxations are {\\it convective} (ballistic-like). We cast this novel idea in the rigorous form of a self-consistent nonlinear dynamical model, which generalizes the classic equations of the quasi-linear theory to "broad" beams with internal structure. We also present numerical simulation results of the relaxation of a broad beam of energetic particles in cold plasma. These generally demonstrate the mixed diffusive-convective features of supra-thermal particle transport; and essentially depend on nonlinear wave-particle interactions and phase-space structures. Taking into account modes of the stable linear spectrum is crucial for the self-consistent evolution of the distribution f...

  1. Method for maximizing the brightness of the bunches in a particle injector by converting a highly space-charged beam to a relativistic and emittance-dominated beam

    Energy Technology Data Exchange (ETDEWEB)

    Hannon, Fay

    2016-08-02

    A method for maximizing the brightness of the bunches in a particle injector by converting a highly space-charged beam to a relativistic and emittance-dominated beam. The method includes 1) determining the bunch charge and the initial kinetic energy of the highly space-charge dominated input beam; 2) applying the bunch charge and initial kinetic energy properties of the highly space-charge dominated input beam to determine the number of accelerator cavities required to accelerate the bunches to relativistic speed; 3) providing the required number of accelerator cavities; and 4) setting the gradient of the radio frequency (RF) cavities; and 5) operating the phase of the accelerator cavities between -90 and zero degrees of the sinusoid of phase to simultaneously accelerate and bunch the charged particles to maximize brightness, and until the beam is relativistic and emittance-dominated.

  2. Contribution of High-Order Rainbows to the Scattering of a Gaussian Laser Beam by a Spherical Particle

    Science.gov (United States)

    Lock, James A.

    1993-01-01

    I review the theory of the scattering of a Gaussian laser beam by a dielectric spherical particle and give the details for constructing a computer program to implement the theory. Computational results indicate that if the width of the laser beam is much less than the diameter of the particle and if the axis of the beam is incident near the edge of the particle, the fifth-, sixth-, and ninth-order rainbows should be evident in the far-field scattered intensity. I performed an experiment that yielded tentative evidence for the presence of the sixth- order rainbow.

  3. GLOBAL BLOW-UP FOR A HEAT SYSTEM WITH LOCALIZED SOURCES AND ABSORPTIONS

    Institute of Scientific and Technical Information of China (English)

    Chen Youpeng

    2007-01-01

    In this paper there are established the global existence and finite time blow-up results of nonnegative solution for the following parabolic systemut=Δu+vp(x0, t)-aur, x∈Ω, t>0,vt=Δv+uq(x0,t)-bvs, x∈Ω, t>0subject to homogeneous Dirichlet conditions and nonnegative initial data, where x0 ∈Ω is a fixed point, p, q, r, s ≥ 1 and a, b > 0 are constants. In the situation when nonnegative solution (u, v) of the above problem blows up in finite time, it is showed that the blow-up is global and this differs from the local sources case. Moreover, for the special case r = s = 1,are obtained uniformly on compact subsets of Ω, where T* is the blow-up time.

  4. A blowup criterion for viscous, compressible, and heat-conductive magnetohydrodynamic flows

    Science.gov (United States)

    Du, Lili; Wang, Yongfu

    2015-09-01

    In this paper, we proved a blowup criterion for the two-dimensional (2D) viscous, compressible, and heat-conducting magnetohydrodynamic (MHD) flows for Cauchy problem, which depends only on the divergence of the velocity vector field, as well as for the case of bounded domain with Dirichlet boundary conditions. This result indicates that the nature of the blowup for compressible models of viscous media in 2D space is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model. More precisely, taking into account the magnetic effects and heat conductivity does not introduce any new features in the blowup mechanism of full MHD flows, especially, which is independent of the temperature and the magnetic field. The results also imply the global regularity of the strong solution to compressible MHD flows, provided that velocity divergence remains bounded.

  5. Blowup Phenomenon of Solutions for the IBVP of the Compressible Euler Equations in Spherical Symmetry.

    Science.gov (United States)

    Cheung, Ka Luen; Wong, Sen

    2016-01-01

    The blowup phenomenon of solutions is investigated for the initial-boundary value problem (IBVP) of the N-dimensional Euler equations with spherical symmetry. We first show that there are only trivial solutions when the velocity is of the form c(t)|x| (α-1) x + b(t)(x/|x|) for any value of α ≠ 1 or any positive integer N ≠ 1. Then, we show that blowup phenomenon occurs when α = N = 1 and [Formula: see text]. As a corollary, the blowup properties of solutions with velocity of the form [Formula: see text] are obtained. Our analysis includes both the isentropic case (γ > 1) and the isothermal case (γ = 1).

  6. LIMITING BEHAVIOR OF BLOW-UP SOLUTIONS OF THE NLSE WITH A STARK POTENTIAL

    Institute of Scientific and Technical Information of China (English)

    Zhu Shihui; Zhang Jian

    2012-01-01

    This article is concerned with blow-up solutions of the Cauchy problem of critical nonlinear Schr(o)dinger equation with a Stark potential.By using the variational characterization of corresponding ground state,the limiting behavior of blow-up solutions with critical and small super-critical mass are obtained in the natural energy space ∑ ={u ∈ H1; ∫RN [x|2|u|2dx < +o}.Moreover,an interesting concentration property of the blow-up solutions with critical mass is gotten,which reads that |u(t,x)|2→‖Q‖2L2δx =x1 as t→ T.

  7. Blow-up in p-Laplacian heat equations with nonlinear boundary conditions

    Science.gov (United States)

    Ding, Juntang; Shen, Xuhui

    2016-10-01

    In this paper, we investigate the blow-up of solutions to the following p-Laplacian heat equations with nonlinear boundary conditions: {l@{quad}l}(h(u))_t =nabla\\cdot(|nabla u|pnabla u)+k(t)f(u) &{in } Ω×(0,t^{*}), |nabla u|ppartial u/partial n=g(u) &on partialΩ×(0,t^{*}), u(x,0)=u0(x) ≥ 0 & {in } overline{Ω},. where {p ≥ 0} and {Ω} is a bounded convex domain in {RN}, {N ≥ 2} with smooth boundary {partialΩ}. By constructing suitable auxiliary functions and using a first-order differential inequality technique, we establish the conditions on the nonlinearities and data to ensure that the solution u( x, t) blows up at some finite time. Moreover, the upper and lower bounds for the blow-up time, when blow-up does occur, are obtained.

  8. Observation of a single-beam gradient force acoustical trap for elastic particles: acoustical tweezers

    CERN Document Server

    Baresch, Diego; Marchiano, Régis

    2016-01-01

    The ability to manipulate matter precisely is critical for the study and development of a large variety of systems. Optical tweezers are excellent tools to handle particles ranging in size from a few micrometers to hundreds of nanometers but become inefficient and damaging on larger objects. We demonstrate for the first reported time the trapping of elastic particles by the large gradient force of a single acoustical beam in three dimensions. We show that at equal power, acoustical forces overtake by 8 orders of magnitude that of optical ones on macroscopic objects. Acoustical tweezers can push, pull and accurately control both the position of the particle and the forces exerted under damage-free conditions. The large spectrum of frequencies covered by coherent ultrasonic sources will provide a wide variety of manipulation possibilities from macro- to microscopic length scales. We believe our observations improve the prospects for wider use of non-contact manipulation in biology, biophysics, microfluidics and...

  9. Low-temperature Bessel beam trap for single submicrometer aerosol particle studies

    International Nuclear Information System (INIS)

    We report on a new instrument for single aerosol particle studies at low temperatures that combines an optical trap consisting of two counter-propagating Bessel beams (CPBBs) and temperature control down to 223 K (−50 °C). The apparatus is capable of capturing and stably trapping individual submicrometer- to micrometer-sized aerosol particles for up to several hours. First results from studies of hexadecane, dodecane, and water aerosols reveal that we can trap and freeze supercooled droplets ranging in size from ∼450 nm to 5500 nm (radius). We have conducted homogeneous and heterogeneous freezing experiments, freezing-melting cycles, and evaporation studies. To our knowledge, this is the first reported observation of the freezing process for levitated single submicrometer-sized droplets in air using optical trapping techniques. These results show that a temperature-controlled CPBB trap is an attractive new method for studying phase transitions of individual submicrometer aerosol particles

  10. THE SIMULTANEOUS AND NON-SIMULTANEOUS BLOW-UP CRITERIA FOR A DIFFUSION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Zhengqiu LING; Zejia WANG; Guoqiang ZHANG

    2013-01-01

    This paper investigates the finite time blow-up of nonnegative solutions for a nonlinear diffusion system with a more complicated source term,which is a product of localized source,local source,and weight function,and complemented by homogeneous Dirichlet boundary conditions.The criteria are proposed to identify simultaneous and nonsimultaneous blow-up solutions.Moreover,the related classification for the four parameters in the model is optimal and complete.The results extend those in Zhang and Yang [12].

  11. Blow-up in nonlinear Schroedinger equations. I. A general review

    DEFF Research Database (Denmark)

    Juul Rasmussen, Jens; Rypdal, K.

    1986-01-01

    The general properties of a class of nonlinear Schroedinger equations: iut + p:∇∇u + f(|u|2)u = 0 are reviewed. Conditions for existence, uniqueness, and stability of solitary wave solutions are presented, along with conditions for blow-up and global existence for the Cauchy problem.......The general properties of a class of nonlinear Schroedinger equations: iut + p:∇∇u + f(|u|2)u = 0 are reviewed. Conditions for existence, uniqueness, and stability of solitary wave solutions are presented, along with conditions for blow-up and global existence for the Cauchy problem....

  12. Blow-up Solutions for Mixed Nonlinear Schr(o)dinger Equations

    Institute of Scientific and Technical Information of China (English)

    Shao Bin TAN

    2004-01-01

    This paper is concerned with the initial boundary-value problem for the following nonlinear evolution equation: φt = iαφxx + βφ2-φx + γ|φ|2φx + ig(|φ|2)φ.Under certain conditions on the initial data and the function g(s), we study the existence and nonexistence of global solution for this equation. The blow-up solution and the blow-up time are also investigated.

  13. Blow-up conditions for two dimensional modified Euler-Poisson equations

    Science.gov (United States)

    Lee, Yongki

    2016-09-01

    The multi-dimensional Euler-Poisson system describes the dynamic behavior of many important physical flows, yet as a hyperbolic system its solution can blow-up for some initial configurations. This article strives to advance our understanding on the critical threshold phenomena through the study of a two-dimensional modified Euler-Poisson system with a modified Riesz transform where the singularity at the origin is removed. We identify upper-thresholds for finite time blow-up of solutions for the modified Euler-Poisson equations with attractive/repulsive forcing.

  14. Blow-Up Analysis for a Quasilinear Degenerate Parabolic Equation with Strongly Nonlinear Source

    Directory of Open Access Journals (Sweden)

    Pan Zheng

    2012-01-01

    Full Text Available We investigate the blow-up properties of the positive solution of the Cauchy problem for a quasilinear degenerate parabolic equation with strongly nonlinear source ut=div(|∇um|p−2∇ul+uq,  (x,t∈RN×(0,T, where N≥1, p>2 , and m, l,  q>1, and give a secondary critical exponent on the decay asymptotic behavior of an initial value at infinity for the existence and nonexistence of global solutions of the Cauchy problem. Moreover, under some suitable conditions we prove single-point blow-up for a large class of radial decreasing solutions.

  15. Monte Carlo simulation of small OpenPET prototype with 11C beam irradiation: effects of secondary particles on in-beam imaging

    International Nuclear Information System (INIS)

    In-beam positron emission tomography (PET) can enable visualization of an irradiated field using positron emitters (β+ decay). In particle therapies, many kinds of secondary particles are produced by nuclear interactions, which affect PET imaging. Our purpose in this work was to evaluate effects of secondary particles on in-beam PET imaging using the Monte Carlo simulation code, Geant4, by reproducing an experiment with a small OpenPET prototype in which a PMMA phantom was irradiated by a 11C beam. The number of incident particles to the detectors and their spectra, background coincidence for the PET scan, and reconstructed images were evaluated for three periods, spill-time (beam irradiation), pause-time (accelerating the particles) and beam-off time (duration after the final spill). For spill-time, we tested a background reduction technique in which coincidence events correlated with the accelerator radiofrequency were discarded (RF gated) that has been proposed in the literature. Also, background generation processes were identified. For spill-time, most background coincidences were caused by prompt gamma rays, and only 1.4% of the total coincidences generated β+ signals. Differently, for pause-time and beam-off time, more than 75% of the total coincidence events were signals. Using these coincidence events, we failed to reconstruct images during the spill-time, but we obtained successful reconstructions for the pause-time and beam-off time, which was consistent with the experimental results. From the simulation, we found that the absence of materials in the beam line and using the RF gated technique improved the signal-to-noise ratio for the spill-time. From an additional simulation with range shifter-less irradiation and the RF gated technique, we showed the feasibility of image reconstruction during the spill-time. (paper)

  16. 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

  17. Overview of charged-particle beam diagnostics for the advanced photon source (APS)

    Science.gov (United States)

    Lumpkin, A. H.; Decker, G.; Kahana, E.; Patterson, D.; Sellyey, W.; Votaw, A.; Wang, X.; Chung, Y.

    1992-07-01

    Plans, prototypes, and initial test results for the charged-particle beam (e-,e+) diagnostic systems on the injector rings, their transport lines, and the storage ring for the Advanced Photon Source (APS) are presented. The APS will be a synchrotron radiation user facility with one of the world's brightest x-ray sources in the 10-keV to 100-keV regime. Its 200-MeV electron linac, 450-MeV positron linac, positron accumulator ring, 7-GeV booster synchrotron, 7-GeV storage ring, and undulator test lines will also demand the development and demonstration of key particle-beam characterization techniques over a wide range of parameter space. Some of these parameter values overlap or approach those projected for fourth generation light sources (linac-driven FELs and high brightness storage rings) as described at a recent workshop. Initial results from the diagnostics prototypes on the linac test stand operating at 45-MeV include current monitor data, beam loss monitor data, and video digitization using VME architecture.

  18. Charged-particle beam diagnostics for the Advanced Photon Source (APS)

    Science.gov (United States)

    Lumpkin, A. H.; Decker, G.; Kahana, E.; Patterson, D.; Sellyey, W.; Wang, X.; Chung, Y.

    1992-08-01

    Plans, prototypes, and initial test results for the charged-particle beam (e-), e(+) diagnostic systems on the injector rings, their transport lines, and the storage ring for the Advanced Photon Source (APS) are presented. The APS will be a synchrotron radiation user facility with one of the world's brightest x-ray sources in the 10-keV to 100-keV regime. Its 200-MeV electron linac, 450-MeV positron linac, positron accumulator ring, 7-GeV booster synchrotron, 7-GeV storage ring, and undulator test lines will also demand the development and demonstration of key particle-beam characterization techniques over a wide range of parameter space. Some of these parameter values overlap or approach those projected for fourth generation light sources (linac-driven FELs and high brightness storage rings) as described at a recent workshop. Initial results from the diagnostics prototypes on the linac test stand operating at 45-MeV include current monitor data, beam loss monitor data, and video digitization using VME architecture.

  19. A new method of measurement of trace elements by using particle beams

    International Nuclear Information System (INIS)

    A new method of measurement of light elements by using the particle beam from an accelerator was developed. This paper reports on the results of analyses of N-15 and O-18. The tandem accelerator of University of Tokyo was used to accelerate proton beam. The energy of protons was determined from the excitation curves of elastic scattering by N-15, O-18 and O-16. The scattering by O-16 was background count. Therefore, The measurement was made at the energy of small background and large true counting. Biological samples were examined. The linearity of counts with the concentration of N-15 and O-18 was confirmed. The cells which contain glycine (O-18, 71.8 percent) and methionine (N-15, 95 percent) were analyzed. The peaks of N-15 and O-18 were well separated from teh peaks by N-14 and O-16. The natural amounts of N-15 in adenine and O-18 in glucose were also measured. The resonance reaction method of measurement by using particle beam was developed. (Kato, T.)

  20. Time structure of the particle beam source and current sheath filamentation in the plasma focus

    International Nuclear Information System (INIS)

    In previous work the authors have described a method for determining the energy spectrum N(E) of the ion beam emitted from a localized (point) source in the plasma focus pinch. In systematic applications the time structure of the beam source (dN/dt) is assumed to be the same as that of the x-ray localized source recorded from scintillation detector signal with a ≅ 2-5 ns time resolution [the spectrum is derived from the ion time of flight ΔtΓE/sup -1/2/; Δt from the conditions x(t)xMax N/Max x = N(t + Δt) on x-ray signal (x) and particle signal N]. The energy spectrum with a high resolution (ΔE ≤ 0.0 l E) from an alternative method - i.e. from magnetic analyzer data - is essentially the same as that from time of flight. This confirms that the time structure of the ion beam source in the high energy region (E > 0.3 MeV) fits the x-ray (and electron beam) source structure. At any specific time tau (i.e., within a sufficiently small time interval δt during the emission time ≅ 5-50 ns of the beam) the beam is emitted with an amplitude N(E) which is sharply peaked at a specific value of the energy E = E(tau). A correlation of the filamentary structure of the x-ray source with a filamentary structure of the ion source can also be established on a space scale of ≤ 10μm

  1. Universality of blow-up profile for small radial type II blow-up solutions of energy-critical wave equation

    CERN Document Server

    Duyckaerts, Thomas; Merle, Frank

    2009-01-01

    Consider the energy critical focusing wave equation on the Euclidian space. A blow-up type II solution of this equation is a solution which has finite time of existence but stays bounded in the energy space. The aim of this work is to exhibit universal properties of such solutions. Let W be the unique radial positive stationary solution of the equation. Our main result is that in dimension 3, under an appropriate smallness assumption, any type II blow-up radial solution is essentially the sum of a rescaled W concentrating at the origin and a small remainder which is continuous with respect to the time variable in the energy space. This is coherent with the solutions constructed by Krieger, Schlag and Tataru. One ingredient of our proof is that the unique radial solution which is compact up to scaling is equal to W up to symmetries.

  2. Beam-splitting code for light scattering by ice crystal particles within geometric-optics approximation

    International Nuclear Information System (INIS)

    The open-source beam-splitting code is described which implements the geometric-optics approximation to light scattering by convex faceted particles. This code is written in C++ as a library which can be easy applied to a particular light scattering problem. The code uses only standard components, that makes it to be a cross-platform solution and provides its compatibility to popular Integrated Development Environments (IDE's). The included example of solving the light scattering by a randomly oriented ice crystal is written using Qt 5.1, consequently it is a cross-platform solution, too. Both physical and computational aspects of the beam-splitting algorithm are discussed. Computational speed of the beam-splitting code is obviously higher compared to the conventional ray-tracing codes. A comparison of the phase matrix as computed by our code with the ray-tracing code by A. Macke shows excellent agreement. - Highlights: • The beam-splitting code is presented as open-source software. • Both physical and computational aspects of the code are discussed. • Computational speed of the code is higher than ray-tracing codes. • A comparison with the ray-tracing Macke's code shows excellent agreement

  3. Object-Oriented Parallel Particle-in-Cell Code for Beam Dynamics Simulation in Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J.; Ryne, R.D.; Habib, S.; Decky, V.

    1999-11-13

    In this paper, we present an object-oriented three-dimensional parallel particle-in-cell code for beam dynamics simulation in linear accelerators. A two-dimensional parallel domain decomposition approach is employed within a message passing programming paradigm along with a dynamic load balancing. Implementing object-oriented software design provides the code with better maintainability, reusability, and extensibility compared with conventional structure based code. This also helps to encapsulate the details of communications syntax. Performance tests on SGI/Cray T3E-900 and SGI Origin 2000 machines show good scalability of the object-oriented code. Some important features of this code also include employing symplectic integration with linear maps of external focusing elements and using z as the independent variable, typical in accelerators. A successful application was done to simulate beam transport through three superconducting sections in the APT linac design.

  4. BEAMR: An interactive graphic computer program for design of charged particle beam transport systems

    Science.gov (United States)

    Leonard, R. F.; Giamati, C. C.

    1973-01-01

    A computer program for a PDP-15 is presented which calculates, to first order, the characteristics of charged-particle beam as it is transported through a sequence of focusing and bending magnets. The maximum dimensions of the beam envelope normal to the transport system axis are continuously plotted on an oscilloscope as a function of distance along the axis. Provision is made to iterate the calculation by changing the types of magnets, their positions, and their field strengths. The program is especially useful for transport system design studies because of the ease and rapidity of altering parameters from panel switches. A typical calculation for a system with eight elements is completed in less than 10 seconds. An IBM 7094 version containing more-detailed printed output but no oscilloscope display is also presented.

  5. Principle of a correction of the long-range beam-beam effect in LHC using electromagnetic lenses

    CERN Document Server

    Koutchouk, Jean-Pierre

    2000-01-01

    Due to the small bunch spacing, the beams in LHC collide not only in the four experimental points but experience more than one hundred 'near-misses'. They occur on either side of the collision points in places where the beam separation is in the range of 7 to 13 sigma. These so-called 'long-range'interactions are more and more recognized to be a drastic mechanism leading to beam blow-up or beam loss even-though the tunes of the particles are under control. We show in this note that, contrary to the head-on-beam interaction, a simple non linear model of the long-range interactions can be devised. This model suggests a rather simple correction principle by electromagnetic lenses, basically a wire, which correct with a good accuracy simultaneously the linear and non-linear perturbations. The correction of the average perturbation over all the bunches seems not demanding. An exact correction of the so-called PACMAN bunches may be done at a frequency an order of magnitude lower than the bunch frequency and is bein...

  6. Test-Beam Analysis of the Effect of Highly Ionising Particles on the Silicon Strip Tracker

    CERN Document Server

    Tomalin, Ian R

    2003-01-01

    Highly Ionizing Particles (HIPs) created by nuclear interactions in the tracker sensors produce large signals which can momentarily saturate an APV readout chip. This phenomenon is studied in two different beam-tests performed at PSI and X5 in 2002. The probability of a HIP-like event occurring per incident pion is measured, as is the time required for an APV to recover from such an event. Distortions induced in the APV baseline are also studied. From these results, the expected inefficiency of the CMS Tracker due to HIPs is inferred. The dependence of the results on the APV's configuration parameters and inverter stage resistor value is shown.

  7. Trochoidal trajectories of self-propelled Janus particles in a diverging laser beam

    CERN Document Server

    Moyses, Henrique; Sacanna, Stefano; Grier, David G

    2016-01-01

    We describe colloidal Janus particles with metallic and dielectric faces that swim vigorously when illuminated by defocused optical tweezers without consuming any chemical fuel. Rather than wandering randomly, these optically-activated colloidal swimmers circulate back and forth through the beam of light, tracing out sinuous rosette patterns. We propose a model for this mode of light-activated transport that accounts for the observed behavior through a combination of self-thermophoresis and optically-induced torque. In the deterministic limit, this model yields trajectories that resemble rosette curves known as hypotrochoids.

  8. A blow-up criterion for classical solutions to the compressible Navier-Stokes equations

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we obtain a blow-up criterion for classical solutions to the 3-D compressible Navier-Stokes equations just in terms of the gradient of the velocity, analogous to the Beal-Kato-Majda criterion for the ideal incompressible flow. In addition, the initial vacuum is allowed in our case.

  9. Blow-up and Global Smooth Solutions for Incompressible Three-Dimensional Navier-Stokes Equations

    Institute of Scientific and Technical Information of China (English)

    GUO Bo-Ling; YANG Gan-Shan; PU Xue-Ke

    2008-01-01

    We present some explicit self-similar blow-up solutions and some other solutions of the incompressible three-dimensional Navier-Stokes equations. These solutions indicate that in C∞ the solution of Navier-Stokes equations does not always tend to a solution of Euler equations.

  10. WELL-POSEDNESS, DECAY ESTIMATES AND BLOW-UP THEOREM FOR THE FORCED NLS

    Institute of Scientific and Technical Information of China (English)

    Charles Bu; Randy Shull; Hefei Wang; Millie Chu

    2001-01-01

    In this article we prove that the following NLS iut = uxx -g|u|P-1u, g >0, x, t > 0 with either Dirichlet or Robin boundary condition at x = 0 is well-posed.Lp+1 decay estimates, blow-up theorem and numerical results are also given.

  11. Blow-up estimates for semilinear parabolic systems coupled in an equation and a boundary condition

    Institute of Scientific and Technical Information of China (English)

    WANG; Mingxin(

    2001-01-01

    [1]Wang, S., Wang, M. X., Xie, C. H., Reaction-diffusion systems with nonlinear boundary conditions, Z. angew. Math.Phys., 1997, 48(6): 994-1001.[2]Fila, M., Quittner, P., The blow-up rate for a semilinear parabolic system, J. Math. Anal. Appl., 1999, 238: 468-476.[3]Hu, B., Remarks on the blow-up estimate for solutions of the heat equation with a nonlinear boundary condition, Differential Integral Equations, 1996, 9(5): 891-901.[4]Hu, B. , Yin, H. M., The profile near blow-up time for solution of the heat equation with a nonlinear boundary condition,Trans. of Amer. Math. Soc., 1994, 346: 117-135.[5]Amann, H., Parabolic equations and nonlinear boundary conditions, J. of Diff. Eqns., 1988, 72: 201-269.[6]Deng, K., Blow-up rates for parabolic systems, Z. angew. Math. Phys. ,1996, 47: 132-143.[7]Fila, M., Levine, H. A., On critical exponents for a semilinear parabolic system coupled in an equation and a boundary condition, J. Math. Anal. Appl., 1996, 204: 494-521.

  12. On the Blow-up Criterion of Magnetohydrodynamics Equations in Homogeneous Sobolev Spaces

    OpenAIRE

    Marcon, Diego; Melo, Wilberclay G.; Schutz, Lineia; Ziebell, Juliana S.

    2015-01-01

    In this paper, we obtain new lower bounds on the Homogeneous Sobolev--norms of the maximal solution of the Magnetohydrodynamics Equations. This gives us some insight on the blow-up behavior of the solution. We utilize standard techniques from the Navier--Stokes Equations.

  13. The differential equations defining deflection of particles of ion beam from axial trajectory in electric and magnetic fields

    International Nuclear Information System (INIS)

    The exact differential equations defining deviations of the paths of charged particles from the axial trajectory are derived in curvilinear coordinates. These equations are in a form suited for carrying out relativistically correct numerical calculations of the dynamics of charged particle beams.

  14. Uniform blow-up profiles and boundary layer for a parabolic system with localized nonlinear reaction terms

    Institute of Scientific and Technical Information of China (English)

    LI; Huiling; WANG; Mingxin

    2005-01-01

    This paper deals with the blow-up properties of the solution to a semilinear parabolic system with localized nonlinear reaction terms, subject to the null Dirichlet boundary condition. We first give sufficient conditions for that the classical solution blows up in the finite time, secondly give necessary conditions and a sufficient condition for that two components blow up simultaneously, and then obtain the uniform blow-up profiles in the interior. Finally we describe the asymptotic behavior of the blow-up solution in the boundary layer.

  15. Blow-up of solutions of non-linear equations of Kadomtsev-Petviashvili and Zakharov-Kuznetsov types

    Science.gov (United States)

    Korpusov, M. O.; Sveshnikov, A. G.; Yushkov, E. V.

    2014-06-01

    The Kadomtsev-Petviashvili equation and Zakharov-Kuznetsov equation are important in physical applications. We obtain sufficient conditions for finite-time blow-up of solutions of these equations in bounded and unbounded domains. We describe how the initial data influence the blow-up time. To do this, we use the non-linear capacity method suggested by Pokhozhaev and Mitidieri and combine it with the method of test functions, which was developed in joint papers with Galaktionov. Note that our results are the first blow-up results for many equations in this class.

  16. Monte Carlo N Particle code - Dose distribution of clinical electron beams in inhomogeneous phantoms

    Directory of Open Access Journals (Sweden)

    H A Nedaie

    2013-01-01

    Full Text Available Electron dose distributions calculated using the currently available analytical methods can be associated with large uncertainties. The Monte Carlo method is the most accurate method for dose calculation in electron beams. Most of the clinical electron beam simulation studies have been performed using non- MCNP [Monte Carlo N Particle] codes. Given the differences between Monte Carlo codes, this work aims to evaluate the accuracy of MCNP4C-simulated electron dose distributions in a homogenous phantom and around inhomogeneities. Different types of phantoms ranging in complexity were used; namely, a homogeneous water phantom and phantoms made of polymethyl methacrylate slabs containing different-sized, low- and high-density inserts of heterogeneous materials. Electron beams with 8 and 15 MeV nominal energy generated by an Elekta Synergy linear accelerator were investigated. Measurements were performed for a 10 cm × 10 cm applicator at a source-to-surface distance of 100 cm. Individual parts of the beam-defining system were introduced into the simulation one at a time in order to show their effect on depth doses. In contrast to the first scattering foil, the secondary scattering foil, X and Y jaws and applicator provide up to 5% of the dose. A 2%/2 mm agreement between MCNP and measurements was found in the homogenous phantom, and in the presence of heterogeneities in the range of 1-3%, being generally within 2% of the measurements for both energies in a "complex" phantom. A full-component simulation is necessary in order to obtain a realistic model of the beam. The MCNP4C results agree well with the measured electron dose distributions.

  17. Stationary self-consistent distributions for a charged particle beam in the longitudinal magnetic field

    Science.gov (United States)

    Drivotin, O. I.; Ovsyannikov, D. A.

    2016-09-01

    A review of analytical solutions of the Vlasov equation for a beam of charged particles is given. These results are analyzed on the basis of a unified approach developed by the authors. In the context of this method, a space of integrals of motion is introduced in which the integrals of motion of particles are considered as coordinates. In this case, specifying a self-consistent distribution is reduced to defining a distribution density in this space. This approach allows us to simplify the construction and analysis of different self-consistent distributions. In particular, it is possible, in some cases, to derive new solutions by considering linear combinations of well-known solutions. This approach also makes it possible in many cases to give a visual geometric representation of self-consistent distributions in the space of integrals of motion.

  18. Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film

    Directory of Open Access Journals (Sweden)

    Benpeng Zhu

    2016-03-01

    Full Text Available Single-beam acoustic tweezers (SBAT, used in laboratory-on-a-chip (LOC device has promising implications for an individual micro-particle contactless manipulation. In this study, a freestanding hydrothermal PZT thick film with excellent piezoelectric property (d33 = 270pC/N and kt = 0.51 was employed for SBAT applications and a press-focusing technology was introduced. The obtained SBAT, acting at an operational frequency of 50MHz, a low f-number (∼0.9, demonstrated the capability to trap and manipulate a micro-particle sized 10μm in the distilled water. These results suggest that such a device has great potential as a manipulator for a wide range of biomedical and chemical science applications.

  19. Particle beam experiments for the investigation of plasma-surface interactions: application to magnetron sputtering and polymer treatment

    CERN Document Server

    Corbella, Carles; Kreiter, Oliver; Arcos, Teresa de los; Benedikt, Jan; von Keudell, Achim

    2013-01-01

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions. Atom and ion beams are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions and metal vapor. The heterogeneous surface processes are monitored in-situ and in real time by means of a quartz crystal microbalance (QCM) and Fourier transform infrared spectroscopy (FTIR). Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma treatment of polymers (PET, PP).

  20. Energy Transport Effects in Flaring Atmospheres Heated by Mixed Particle Beams

    Science.gov (United States)

    Zharkova, Valentina; Zharkov, Sergei; Macrae, Connor; Druett, Malcolm; Scullion, Eamon

    2016-07-01

    We investigate energy and particle transport in the whole flaring atmosphere from the corona to the photosphere and interior for the flaring events on the 1st July 2012, 6 and 7 September 2011 by using the RHESSI and SDO instruments as well as high-resolution observations from the Swedish 1-metre Solar Telescope (SST3) CRISP4 (CRisp Imaging Spectro-polarimeter). The observations include hard and soft X-ray emission, chromospheric emission in both H-alpha 656.3 nm core and continuum, as well as, in the near infra-red triplet Ca II 854.2 nm core and continuum channels and local helioseismic responses (sunquakes). The observations are compared with the simulations of hard X-ray emission and tested by hydrodynamic simulations of flaring atmospheres of the Sun heated by mixed particle beams. The temperature, density and macro-velocity variations of the ambient atmospheres are calculated for heating by mixed beams and the seismic response of the solar interior to generation of supersonic shocks moving into the solar interior. We investigate the termination depths of these shocks beneath the quiet photosphere levels and compare them with the parameters of seismic responses in the interior, or sunquakes (Zharkova and Zharkov, 2015). We also present an investigation of radiative conditions modelled in a full non-LTE approach for hydrogen during flare onsets with particular focus on Balmer and Paschen emission in the visible, near UV and near IR ranges and compare them with observations. The links between different observational features derived from HXR, optical and seismic emission are interpreted by different particle transport models that will allow independent evaluation of the particle transport scenarios.

  1. Beam energy dependence of pseudorapidity distributions of charged particles produced in relativistic heavy-ion collisions

    Science.gov (United States)

    Basu, Sumit; Nayak, Tapan K.; Datta, Kaustuv

    2016-06-01

    Heavy-ion collisions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN probe matter at extreme conditions of temperature and energy density. Most of the global properties of the collisions can be extracted from the measurements of charged-particle multiplicity and pseudorapidity (η ) distributions. We have shown that the available experimental data on beam energy and centrality dependence of η distributions in heavy-ion (Au +Au or Pb +Pb ) collisions from √{sNN}=7.7 GeV to 2.76 TeV are reasonably well described by the AMPT model, which is used for further exploration. The nature of the η distributions has been described by a double Gaussian function using a set of fit parameters, which exhibit a regular pattern as a function of beam energy. By extrapolating the parameters to a higher energy of √{sNN}=5.02 TeV, we have obtained the charged-particle multiplicity densities, η distributions, and energy densities for various centralities. Incidentally, these results match well with some of the recently published data by the ALICE Collaboration.

  2. Numerical Approach of Interactions of Proton Beams and Dense Plasmas with Quantum-Hydrodynamic/Particle-in-Cell Model

    Science.gov (United States)

    Zhang, Ya; Li, Lian; Jiang, Wei; Yi, Lin

    2016-07-01

    A one dimensional quantum-hydrodynamic/particle-in-cell (QHD/PIC) model is used to study the interaction process of an intense proton beam (injection density of 1017 cm‑3) with a dense plasma (initial density of ~ 1021 cm‑3), with the PIC method for simulating the beam particle dynamics and the QHD model for considering the quantum effects including the quantum statistical and quantum diffraction effects. By means of the QHD theory, the wake electron density and wakefields are calculated, while the proton beam density is calculated by the PIC method and compared to hydrodynamic results to justify that the PIC method is a more suitable way to simulate the beam particle dynamics. The calculation results show that the incident continuous proton beam when propagating in the plasma generates electron perturbations as well as wakefields oscillations with negative valleys and positive peaks where the proton beams are repelled by the positive wakefields and accelerated by the negative wakefields. Moreover, the quantum correction obviously hinders the electron perturbations as well as the wakefields. Therefore, it is necessary to consider the quantum effects in the interaction of a proton beam with cold dense plasmas, such as in the metal films. supported by National Natural Science Foundation of China (Nos. 11405067, 11105057, 11275007)

  3. A Note on the Blow-up Criterion of Smooth Solutions to the 3D Incompressible MHD Equations

    Institute of Scientific and Technical Information of China (English)

    Sadek GALA

    2012-01-01

    In this note,we will give a new proof of the blow-up criterion of smooth solutions to the 3D incompressible magneto-hydrodynamic equations by a simple application of Gagliardo-Nirenberg' s inequality.

  4. Novel Hamiltonian method for collective dynamics analysis of an intense charged particle beam propagating through a periodic focusing quadrupole lattice

    International Nuclear Information System (INIS)

    Identifying regimes for quiescent propagation of intense beams over long distances has been a major challenge in accelerator research. In particular, the development of systematic theoretical approaches that are able to treat self-consistently the applied oscillating force and the nonlinear self-field force of the beam particles simultaneously has been a major challenge of modern beam physics. In this paper, the recently developed Hamiltonian averaging technique [E. A. Startsev, R. C. Davidson, and M. Dorf, Phys. Rev. ST Accel. Beams 13, 064402 (2010)] which incorporates both the applied periodic focusing force and the self-field force of the beam particles, is generalized to the case of time-dependent beam distributions. The new formulation allows not only a determination of quasi-equilibrium solutions of the non-linear Vlasov-Poison system of equations but also a detailed study of their stability properties. The corrections to the well-known ''smooth-focusing'' approximation are derived, and the results are applied to a matched beam with thermal equilibrium distribution function. It is shown that the corrections remain small even for moderate values of the vacuum phase advance συ. Nonetheless, because the corrections to the average self-field potential are non-axisymmetric, the stability properties of the different beam quasi-equilibria can change significantly.

  5. Measurement of charged particle yields from therapeutic beams in view of the design of an innovative hadrontherapy dose monitor

    CERN Document Server

    Battistoni, G; Bini, F; Collamati, F; Collini, F; De Lucia, E; Durante, M; Faccini, R; Ferroni, F; Frallicciardi, P M; La Tessa, C; Marafini, M; Mattei, I; Miraglia, F; Morganti, S; Ortega, P G; Patera, V; Piersanti, L; Pinci, D; Russomando, A; Sarti, A; Schuy, C; Sciubba, A; Senzacqua, M; Solfaroli Camillocci, E; Vanstalle, M; Voena, C

    2015-01-01

    Particle Therapy (PT) is an emerging technique, which makes use of charged particles to efficiently cure different kinds of solid tumors. The high precision in the hadrons dose deposition requires an accurate monitoring to prevent the risk of under-dosage of the cancer region or of over-dosage of healthy tissues. Monitoring techniques are currently being developed and are based on the detection of particles produced by the beam interaction into the target, in particular: charged particles, result of target and/or projectile fragmentation, prompt photons coming from nucleus de-excitation and back-to-back γ s, produced in the positron annihilation from β + emitters created in the beam interaction with the target. It has been showed that the hadron beam dose release peak can be spatially correlated with the emission pattern of these secondary particles. Here we report about secondary particles production (charged fragments and prompt γ s) performed at different beam and energies that have a particular relevan...

  6. Search for eV (pseudo)scalar penetrating particles in the SPS neutrino beam

    CERN Document Server

    Astier, Pierre; Baldisseri, Alberto; Baldo-Ceolin, Massimilla; Ballocchi, G; Banner, M; Bassompierre, Gabriel; Benslama, K; Besson, N; Bird, I G; Blumenfeld, B; Bobisut, F; Bouchez, J; Boyd, S; Bueno, A G; Bunyatov, S A; Camilleri, L L; Cardini, A; Cattaneo, Paolo Walter; Cavasinni, V; Cervera-Villanueva, A; Collazuol, G; Conforto, G; Conta, C; Contalbrigo, M; Cousins, R D; Daniels, D C; Degaudenzi, H M; Del Prete, T; De Santo, A; Dignan, T; Di Lella, L; do Couto e Silva, E; Dumarchez, J; Ellis, M; Feldman, G J; Ferrari, R; Ferrère, D; Flaminio, Vincenzo; Fraternali, M; Gaillard, Jean-Marc; Gangler, E; Geiser, A; Geppert, D; Gibin, D; Gninenko, S N; Godley, A; Gómez-Cadenas, J J; Gosset, J; Gössling, C; Gouanère, M; Grant, A; Graziani, G; Guglielmi, A M; Hagner, C; Hernando, J; Hubbard, D B; Hurst, P; Hyett, N; Iacopini, E; Joseph, C L; Juget, F R; Kirsanov, M M; Klimov, O L; Kokkonen, J; Kovzelev, A; Krasnikov, N V; Krasnoperov, A V; Kuznetsov, V E; Lacaprara, S; Lachaud, C; Lakic, B; Lanza, A; La Rotonda, L; Laveder, M; Letessier-Selvon, A A; Lévy, J M; Linssen, Lucie; Ljubicic, A; Long, J; Lupi, A; Marchionni, A; Martelli, F; Méchain, X; Mendiburu, J P; Meyer, J P; Mezzetto, Mauro; Mishra, S R; Moorhead, G F; Mossuz, L; Nédélec, P; Nefedov, Yu A; Nguyen-Mau, C; Orestano, D; Pastore, F; Peak, L S; Pennacchio, E; Pessard, H; Petti, R; Placci, Alfredo; Polesello, G; Pollmann, D; Polyarush, A Yu; Popov, B; Poulsen, C; Rico, J; Roda, C; Rubbia, André; Salvatore, F; Schahmaneche, K; Schmidt, B; Schmidt, T; Sevior, M E; Sillou, D; Soler, F J P; Sozzi, G; Steele, D; Steininger, M; Stiegler, U; Stipcevic, M; Stolarczyk, T; Tareb-Reyes, M; Taylor, G N; Tereshchenko, V V; Toropin, A N; Touchard, A M; Tovey, Stuart N; Tran, M T; Tsesmelis, E; Ulrichs, J; Vacavant, L; Valdata-Nappi, M; Valuev, V Yu; Vannucci, François; Varvell, K E; Veltri, M; Vercesi, V; Verkindt, D; Vieira, J M; Vinogradova, T G; Volkov, S A; Weber, F V; Weisse, T; Wilson, F F; Winton, L J; Yabsley, B D; Zaccone, Henri; Zioutas, Konstantin; Zuber, K; Zuccon, P

    2000-01-01

    We carried out a model-independent search for light scalar or pseudoscalar particles $a$'s (an example of which is the axion) that couple to two photons by using a photon-regeneration method at high energies allowing a substantial increase in the sensitivity to $eV$ masses.\\ The experimental set-up is based on elements of the CERN West Area Neutrino Facility (WANF) beam line and theNOMAD neutrino detector.\\ The new particles, if they exist, could be produced through the Primakoff effect in interactions of high energy photons, generated by the 450 $GeV$ protons in the CERN SPS neutrino target, with virtual photons from the WANF horn magnetic field.\\ The particles would penetrate the downstream shieldingand would be observed in the NOMAD neutrino detector through their re-conversion into real high energy photons byinteracting with the virtual photons from the magnetic field of the NOMAD dipole magnet.\\ From the analysis of the data collected during the 1996 run with $1.08\\times10^{19}$ protons on target, 312 ca...

  7. Study of Cl containing urban aerosol particles by ion beam analytical methods

    International Nuclear Information System (INIS)

    particles. Mg:Cl (seasalt) and K:Cl (fertilizer) elemental ratios were also studied, and in few cases correlations were found between these elements too. In spring and summer 2008 the Na-Cl correlation was weaker, the Ca-Cl stronger than other times. The hierarchical cluster analysis resulted in 11 groups. The analysis showed that the main origin of the Debrecen coarse mode aerosol was mineral dust. There were four groups which explained sources of Cl. One of these groups was rich in NaCl, KCl and P. The city is surrounded by agricultural areas and farmers use fertilizers containing these compounds. Thus this source was identified as agriculture through fertilizers. In the following group sea-salt was observed through significantly increased concentration of NaCl, MgCl, and Sr. The third group was responsible for 14% of the particles, and was characteristic to winter. Thus this source was appointed to winter salting of streets. The fourth cluster with 13% of the particles was rich in CaS (gypsum) and Ca-Cl correlation was high. This phenomenon could be explained by a construction near to the sampling place. Single particle analysis by ion beam analytical methods proved to be a useful tool for source characterization of urban atmospheric aerosol through providing significant additional information about the origin and formation of Cl containing aerosol. Acknowledgement This work was supported by the Hungarian Research Fund OTKA and the EGT Norwegian Financial Mechanism Programme (contract no. NNF78829) and the EU co-funded Economic Competitiveness Operative Program (contract no. GVOP-3.2.1.-2004-04-0402/3.0).

  8. Analytical linear energy transfer model including secondary particles: calculations along the central axis of the proton pencil beam

    Science.gov (United States)

    Marsolat, F.; De Marzi, L.; Pouzoulet, F.; Mazal, A.

    2016-01-01

    In proton therapy, the relative biological effectiveness (RBE) depends on various types of parameters such as linear energy transfer (LET). An analytical model for LET calculation exists (Wilkens’ model), but secondary particles are not included in this model. In the present study, we propose a correction factor, L sec, for Wilkens’ model in order to take into account the LET contributions of certain secondary particles. This study includes secondary protons and deuterons, since the effects of these two types of particles can be described by the same RBE-LET relationship. L sec was evaluated by Monte Carlo (MC) simulations using the GATE/GEANT4 platform and was defined by the ratio of the LET d distributions of all protons and deuterons and only primary protons. This method was applied to the innovative Pencil Beam Scanning (PBS) delivery systems and L sec was evaluated along the beam axis. This correction factor indicates the high contribution of secondary particles in the entrance region, with L sec values higher than 1.6 for a 220 MeV clinical pencil beam. MC simulations showed the impact of pencil beam parameters, such as mean initial energy, spot size, and depth in water, on L sec. The variation of L sec with these different parameters was integrated in a polynomial function of the L sec factor in order to obtain a model universally applicable to all PBS delivery systems. The validity of this correction factor applied to Wilkens’ model was verified along the beam axis of various pencil beams in comparison with MC simulations. A good agreement was obtained between the corrected analytical model and the MC calculations, with mean-LET deviations along the beam axis less than 0.05 keV μm-1. These results demonstrate the efficacy of our new correction of the existing LET model in order to take into account secondary protons and deuterons along the pencil beam axis.

  9. Alpha Particle Emitter Radiolabeled Antibody for Metastatic Cancer: What Can We Learn from Heavy Ion Beam Radiobiology?

    Directory of Open Access Journals (Sweden)

    Hong Song

    2012-06-01

    Full Text Available Alpha-particle emitter labeled monoclonal antibodies are being actively developed for treatment of metastatic cancer due to the high linear energy transfer (LET and the resulting greater biological efficacy of alpha-emitters. Our knowledge of high LET particle radiobiology derives primarily from accelerated heavy ion beam studies. In heavy ion beam therapy of loco-regional tumors, the modulation of steep transition to very high LET peak as the particle approaches the end of its track (known as the Bragg peak enables greater delivery of biologically potent radiation to the deep seated tumors while sparing normal tissues surrounding the tumor with the relatively low LET track segment part of the heavy ion beam. Moreover, fractionation of the heavy ion beam can further enhance the peak-to-plateau relative biological effectiveness (RBE ratio. In contrast, internally delivered alpha particle radiopharmaceutical therapy lack the control of Bragg peak energy deposition and the dose rate is determined by the administered activity, alpha-emitter half-life and biological kinetics of the radiopharmaceutical. The therapeutic ratio of tumor to normal tissue is mainly achieved by tumor specific targeting of the carrier antibody. In this brief overview, we review the radiobiology of high LET radiations learned from ion beam studies and identify the features that are also applicable for the development of alpha-emitter labeled antibodies. The molecular mechanisms underlying DNA double strand break repair response to high LET radiation are also discussed.

  10. Optimisation of numerical methods for plasma physics. Application to charged particle beams

    International Nuclear Information System (INIS)

    This thesis presents different numerical methods in order to simulate plasmas or charged particles beams with reduced cost. Movement of charged particles in an electromagnetic field is given by the Vlasov equation. This equation is coupled to the Maxwell equations for the electromagnetic field, or to the Poisson equation in a more simple case. Several models exist for solving this system. In kinetic models, particles are represented by a distribution function f(x,v,t) verifying the Vlasov equation. In the general 3-dimensional case, 7 variables appear in the system and computations become heavy. Fluid models consider macroscopic quantities linked to f, such as density, mean velocity and temperature. These quantities only depend on position x and time t. The cost, but also the precision, are reduced. In the first part of this thesis, a multi-fluid method is used for solving the 1-dimensional Vlasov-Poisson system. It is based on the 'a priori' knowledge of the shape of f. Two possibilities are studied: a sum of Dirac masses and the multi-water-bag model. This kind of methods is rather adapted to systems staying close to the equilibrium. The second part presents the decomposition of f between an equilibrium part and a perturbation. The equilibrium part is solved by a fluid method whereas we use a kinetic method for the perturbation. We construct an asymptotic preserving scheme for the Vlasov-Poisson-BGK system using such a decomposition. The third part deals with the Particle-In-Cell (PIC) method in 2D axisymmetric geometry. A work based on iso-geometric analysis is presented, and then a PIC - Discontinuous Galerkin program computed on graphic card (GPU). This architecture reduces significantly calculation time. (author)

  11. Single-particle And Collective Effects Of Cubic Nonlinearity In The Beam Dynamics Of Proton Synchrotrons

    CERN Document Server

    Tran Hy, J

    1998-01-01

    This thesis describes some new studies of the effects of cubic nonlinearities arising from image-charge forces and octupole magnets on the transverse beam dynamics of proton synchrotrons and storage rings, and also a study of the damping of coherent oscillations using a feed-back damper. In the latter case, various corrective algorithms were modeled using linear one-turn maps. Kicks of fixed amplitude but appropriate sign were shown to provide linear damping and no coherent tune shift, though the rate predicted analytically was somewhat higher than that observed in simulations. This algorithm gave much faster damping (for equal power) than conventional proportional kicks, which damp exponentially. Two single-particle effects of the image-change force were investigated: distortion of the momentum dispersion function and amplitude dependence of the betatron tunes (resulting in tune spread). The former is calculated using transfer maps and the method of undetermined coefficients, the latter by solving the cubic ...

  12. Finite element model updating approach to damage identification in beams using particle swarm optimization

    Science.gov (United States)

    Saada, Mohamed M.; Arafa, Mustafa H.; Nassef, Ashraf O.

    2013-06-01

    The use of vibration-based techniques in damage identification has recently received considerable attention in many engineering disciplines. While various damage indicators have been proposed in the literature, those relying only on changes in the natural frequencies are quite appealing since these quantities can conveniently be acquired. Nevertheless, the use of natural frequencies in damage identification is faced with many obstacles, including insensitivity and non-uniqueness issues. The aim of this article is to develop a viable damage identification scheme based only on changes in the natural frequencies and to attempt to overcome the challenges typically encountered. The proposed methodology relies on building a finite element model (FEM) of the structure under investigation. An improved particle swarm optimization algorithm is proposed to facilitate updating the FEM in accordance with experimentally determined natural frequencies in order to predict the damage location and extent. The method is tested on beam structures and was shown to be an effective tool for damage identification.

  13. A Multimedia Tutorial for Charged-Particle Beam Dynamics. Final report

    International Nuclear Information System (INIS)

    In September 1995 WhistleSoft, Inc., began developing a computer-based multimedia tutorial for charged-particle beam dynamics under Phase II of a Small Business Innovative Research grant from the U.S. Department of Energy. In Phase I of this project (see its Final Report) we had developed several prototype multimedia modules using an authoring system on NeXTStep computers. Such a platform was never our intended target, and when we began Phase II we decided to make the change immediately to develop our tutorial modules for the Windows and Macintosh microcomputer market. This Report details our progress and accomplishments. It also gives a flavor of the look and feel of the presently available and upcoming modules

  14. Fifteen symposia on microdosimetry: implications for modern particle-beam cancer radiotherapy

    CERN Document Server

    Wambersie, A; Gueulette, J; Pihet, P

    2015-01-01

    The objective of microdosimetry was, and still is, to identify physical descriptions of the initial physical processes of ionising radiation interacting with biological matter which correlate with observed radiobiological effects with a view to improve the understanding of radiobiological mechanisms and effects. The introduction of therapy with particles starting with fast neutrons followed by negative pions, protons and light ions necessitated the application of biological weighting factors for absorbed dose in order to account for differences of the relative biological effectiveness (RBE). Dedicated radiobiological experiments in therapy beams with mammalian cells and with laboratory animals provided sets of RBE values which are used to evaluate empirical ‘clinical RBE values’. The combination of such experiments with microdosimetric measurements in identical conditions offered the possibility to establish semi-empirical relationships between microdosimetric parameters and results of RBE studies.

  15. Production of shower particles from various beam collisions with different emulsion targets

    CERN Document Server

    Elnagdy, M S

    2003-01-01

    The reaction cross sections for 4.5 A GeV/cP, d, sup 4 He, sup 6 He, sup 6 Li, sup 7 Li, sup 1 sup 2 C, sup 1 sup 6 C, sup 1 sup 6 O, sup 2 sup 4 Mg, sup 2 sup * Si and sup 3 sup 2 S beams with different chemical components of emulsion nuclei are studied with high statistics, and compared with the calculations according to Glauber model. The multiplicity distributions of shower produced particles from the interactions with light and heavy emulsion nuclei are analyzed in terms of the negative binomial and Poisson laws. Some of the present negative binomial parameters agree with the corresponding ones obtained from the propane bubble chamber.

  16. Dosimetry and monitoring of thin X-ray beam produced by linear particle accelerator, for application in radiography

    International Nuclear Information System (INIS)

    The dosimetry and monitoring characteristics of thin X-ray beams, and the application of 4MeV linear particle accelerator to radiosurgery are studied. An addition collimation system, consisted of 3 lead collimators, which allows to obtain thin beams of 6,10 and 15 mm of diameter, was fabricated. The stereo taxic system, together with modifications in dispositives, provide the accuracy required in volum-targed location. The dosimetric informations were determined with silicon detector inserted into water simulator. The isodose curves for each beam, and total isodoses simulating the treatment were established using radiographic emulsions in conditions which reproduce real circunstances of pacient irradiation. (M.C.K.)

  17. Particle production in hadron-proton interactions at 250 GeV/c incident beam momentum

    International Nuclear Information System (INIS)

    In this thesis several characteristic properties are described of π+p, K+p and pp collisions at an incident beam momentum of 250 GeV/c, and compared to characteristics of other energy. The experiment has been performed in the European Hybrid Spectrometer (EHS) exposed to a tagged meson enriched beam. The rapid cycling bubble-chamber and the other detector elements which comprise EHS are described in Ch. 2. Events used for the analysis have been scanned, measured and merged with the electronic counter information. After the merge steps the data have been processed through a chain of reconstruction programs (Ch. 3). In Ch. 4 the multiplicity distributions and topological cross sections are presented. An introduction to the models (Monte Carlo programs) is given in Ch. 5. In Ch. 6 the characteristics of charged particle production in π+p, K+p and pp collisions at 250 GeV/c are presented. In Ch. 7 the forward π0 production is presented, a study of rho and omega resonance production in the forward hemisphere in Ch. 8. In Ch. 6, 7 and 8, the data are compared to predictions from the Monte Carlo programs described in Ch. 5. 117 refs.; 70 figs.; 23 tabs

  18. Plasma opening switch development for the Particle Beam Fusion Accelerator II (PBFA II)

    International Nuclear Information System (INIS)

    The authors conducted plasma opening switch (POS) experiments on Sandia National Laboratories' new Particle Beam Fusin Accelerator II (PBFA II) (12 MV, 100 TW, 50 ns), on the Supermite accelerator (2 MV, 2 TW, 50 ns) and on the Naval Research Laboratory's Gamble II accelerator (1.8 MV, 1.6 TW, 70 ns). The POS systems on the PBFA II and Supermite accelerators use a newly developed flashboard plasma source to provide the plasma necessary to conduct the large (> 1 MA) currents produced byu these accelerators. In the Supermite experiments, the plasma opening switch conducted currents up to 1 MA before opening in less than 10 ns into an electron beam load. These experiments achieved significant voltage gain relative to the voltage across a matched load. In experiments on Gamble II, power gains of up to 1.7 were achieved using a POS in a strongly coaxial geometry (r/sub outer//r/sub inner/ = 2) with a large magnetic field at the cathode. The POS system on PBFA II is unique because of its size and voltage. This POS system is designed to conduct over 6 MA before opening. In present experiments it has conducted currents of 4-5 MA for over 50 ns

  19. A Hybrid Particle Swarm Optimization (PSO-Simplex Algorithm for Damage Identification of Delaminated Beams

    Directory of Open Access Journals (Sweden)

    Xiangdong Qian

    2012-01-01

    Full Text Available Delamination is a type of representative damage in composite structures, severely degrading structural integrity and reliability. The identification of delamination is commonly treated as an issue of nondestructive testing. Differing from existing studies, a hybrid optimization algorithm (HOA, combining particle swarm optimization (PSO with simplex method (SM, is proposed to identify delamination in laminated beams. The objective function of the optimization problem is created using delamination variables (optimization parameters together with actually measured modal frequencies. The HOA adopts a hierarchical and cooperative regime of global search and local search to optimize the objective function. The PSO performs global search for objective function space to achieve a preliminary solution specifying a local potential space. Initialized by this preliminary solution, the SM executes local search for the local potential space to explore the optimal solution. The HOA is validated by a series of simulated delamination scenarios, and the results show that it can identify delamination in laminated beams with decent accuracy, reliability and efficiency. The method proposed holds promise for establishing online damage detection system beneficial for health monitoring of laminated composite structures.

  20. Identified particle production and freeze-out properties in heavy-ion collisions at RHIC Beam Energy Scan program

    CERN Document Server

    ,

    2014-01-01

    The first phase of Beam Energy Scan (BES) program at the Relativistic Heavy-Ion Collider (RHIC) was started in the year 2010 with the aim to study the several aspects of the quantum chromodynamics (QCD) phase diagram. The Solenoidal Tracker At RHIC (STAR) detector has taken data at $\\sqrt{s_{NN}} = $ 7.7, 11.5, 19.6, 27, and 39 GeV in Au+Au collisions in the years 2010 and 2011 as part of the BES programme. For these beam energies, we present the results on the particle yields, average transverse mass and particle ratios for identified particles in mid-rapidity ($|y|$ < 0.1). The measured particle ratios have been used to study the chemical freeze-out dynamics within the framework of a statistical model.

  1. Identified particle production and freeze-out properties in heavy-ion collisions at RHIC Beam Energy Scan program

    Directory of Open Access Journals (Sweden)

    Das Sabita

    2015-01-01

    Full Text Available The first phase of Beam Energy Scan (BES program at the Relativistic Heavy-Ion Collider (RHIC was started in the year 2010 with the aim to study the several aspects of the quantum chromodynamics (QCD phase diagram. The Solenoidal Tracker At RHIC (STAR detector has taken data at √sNN = 7.7, 11.5, 19.6, 27, and 39 GeV in Au+Au collisions in the years 2010 and 2011 as part of the BES programme. For these beam energies, we present the results on the particle yields, average transverse mass and particle ratios for identified particles in mid-rapidity (|y| < 0.1. The measured particle ratios have been used to study the chemical freezeout dynamics within the framework of a statistical model.

  2. UNIFORM BLOWUP PROFILES FOR DIFFUSION EQUATIONS WITH NONLOCAL SOURCE AND NONLOCAL BOUNDARY

    Institute of Scientific and Technical Information of China (English)

    林支桂; 刘玉荣

    2004-01-01

    Long time behavior of solutions to semilinear parabolic equations with nonlocal nonlinear source ut - △u = ∫Ω g(u)dx inΩ× (0, T) and with nonlocal boundary condition u(x, t) = ∫Ω f(x, y)u(y, t)dy on(e) Ω× (0, T) is studied. The authors establish local existence, global existence and nonexistence of solutions and discuss the blowup properties of solutions. Moveover, they derive the uniform blowup estimates for g(s) = sp(p > 1) and g(s) = es under the assumption fΩ f(x, y)dy < 1 for x ∈(e)Ω.

  3. Profile of Blow-up Solution to Hyperbolic System with Nonlocal Term

    Institute of Scientific and Technical Information of China (English)

    Zhi Wen DUAN; Kwang Ik KIM

    2007-01-01

    This paper is concerned with a nonlocal hyperbolic system as follows:utt=△u+(∫Ωvdx)p for x∈RN,t>0, utt=△v+(∫Ωvdx)q for x∈RN,t>0,u(x,0)=u0(x),ut(x,0)=u01(x) for x∈RN,v(x,0)=u0(x),vt(x,0)=v01(x) for x∈RN,where 1 ≤ N ≤ 3, p ≥ 1, q ≥ 1 and pq > 1. Here the initial values are compactly supported andΩ(∈) RN is a bounded open region. The blow-up curve, blow-up rate and profile of the solution arediscussed.

  4. Minimal blow-up solutions to the mass-critical inhomogeneous NLS equation

    CERN Document Server

    Banica, Valeria; Duyckaerts, Thomas

    2009-01-01

    We consider the mass-critical focusing nonlinear Schrodinger equation in the presence of an external potential, when the nonlinearity is inhomogeneous. We show that if the inhomogeneous factor in front of the nonlinearity is sufficiently flat at a critical point, then there exists a solution which blows up in finite time with the maximal (unstable) rate at this point. In the case where the critical point is a maximum, this solution has minimal mass among the blow-up solutions. As a corollary, we also obtain unstable blow-up solutions of the mass-critical Schrodinger equation on some surfaces. The proof is based on properties of the linearized operator around the ground state, and on a full use of the invariances of the equation with an homogeneous nonlinearity and no potential, via time-dependent modulations.

  5. Development of RFQ particle dynamics simulation tools and validation with beam tests

    Energy Technology Data Exchange (ETDEWEB)

    Maus, Johannes M.

    2010-07-01

    Two different strategies of designing RFQs have been introduced. The analytic description of the electric fields inside the quadrupole channel has been derived and the two term simplification was shown as well as the limitation of these approaches. The main work of this thesis was the implementation and analysis of a multigrid Poisson solver to describe the potential and electric field of RFQs which are needed to simulate the particle dynamics accurately. The main two ingredients of a multigrid Poisson solver are the ability of a Gauss-Seidel iteration method to smooth the error of an approximation within a few iteration steps and the coarse grid principle. The smoothing corresponds to a damping of the high frequency components of the error. After the smoothing, the error term can well be approximated on a coarser grid in which the low frequency components of the error on the fine grid are converted to high frequency errors on the coarse grid which can be damped further with the same Gauss-Seidel method. After implementation, the multigrid Poisson solver was analyzed using two different type of test problems: with and without a charge density. As a charge density, a homogeneously charged ball and cylinder were used to represent the bunched and unbunched beam and placed inside a quadruple channel. The solver showed a good performance. Next, the performance of the solver to calculate the external potentials (and fields) of RFQs was analyzed. Closing the analysis of the external field, the transmission and fraction of accelerated particles of the set of 12 RFQs for the two different methods were shown. In the last chapter of this thesis some experimental work on the MAFF (Munich Accelerator for Fission Fragments) IH-RFQ is described. The MAFF RFQ was designed to accelerate very neutron-rich fission fragments for various experiments. The machine was assembled in Frankfurt and a beam test stand was built. As a part of this thesis the shunt impedance of the structure was

  6. Development of RFQ particle dynamics simulation tools and validation with beam tests

    International Nuclear Information System (INIS)

    Two different strategies of designing RFQs have been introduced. The analytic description of the electric fields inside the quadrupole channel has been derived and the two term simplification was shown as well as the limitation of these approaches. The main work of this thesis was the implementation and analysis of a multigrid Poisson solver to describe the potential and electric field of RFQs which are needed to simulate the particle dynamics accurately. The main two ingredients of a multigrid Poisson solver are the ability of a Gauss-Seidel iteration method to smooth the error of an approximation within a few iteration steps and the coarse grid principle. The smoothing corresponds to a damping of the high frequency components of the error. After the smoothing, the error term can well be approximated on a coarser grid in which the low frequency components of the error on the fine grid are converted to high frequency errors on the coarse grid which can be damped further with the same Gauss-Seidel method. After implementation, the multigrid Poisson solver was analyzed using two different type of test problems: with and without a charge density. As a charge density, a homogeneously charged ball and cylinder were used to represent the bunched and unbunched beam and placed inside a quadruple channel. The solver showed a good performance. Next, the performance of the solver to calculate the external potentials (and fields) of RFQs was analyzed. Closing the analysis of the external field, the transmission and fraction of accelerated particles of the set of 12 RFQs for the two different methods were shown. In the last chapter of this thesis some experimental work on the MAFF (Munich Accelerator for Fission Fragments) IH-RFQ is described. The MAFF RFQ was designed to accelerate very neutron-rich fission fragments for various experiments. The machine was assembled in Frankfurt and a beam test stand was built. As a part of this thesis the shunt impedance of the structure was

  7. The exact asymptotic behavior of boundary blow-up solutions to infinity Laplacian equations

    Science.gov (United States)

    Wan, Haitao

    2016-08-01

    In this paper, we study the asymptotic behavior of viscosity solutions to boundary blow-up elliptic problem {Δ_{∞}u=b(x)f(u), xinΩ, u|_{partialΩ}=+∞,} where {Ω} is a bounded domain with C 2-boundary in {{R}N}, {bin C(bar{Ω})} is positive in {Ω}, which may be vanishing on the boundary, {fin C1([0, ∞))} is regularly varying or is rapidly varying at infinity.

  8. On blowup dynamics in the Keller-Segel model of chemotaxis

    CERN Document Server

    Dejak, S I; Lushnikov, P M; Sigal, I M

    2013-01-01

    We investigate the (reduced) Keller-Segel equations modeling chemotaxis of bio-organisms. We present a formal derivation and partial rigorous results of the blowup dynamics of solution of these equations describing the chemotactic aggregation of the organisms. Our results are confirmed by numerical simulations and the formula we derive coincides with the formula of Herrero and Vel\\'{a}zquez for specially constructed solutions.

  9. Blow-up Estimates of the Positive Solution of a Parabolic System

    DEFF Research Database (Denmark)

    Pedersen, Michael; Zhigui, Lin

    2001-01-01

    This paper establishes the blow-up estimates for the systems u(t) - Deltau = 0, v(t) - Deltav = 0 in B-R x (0, T), B-R subset of R-n, with the nonlinear boundary conditions partial derivativeu/partial derivativen = u(m1)v(n1) and partial derivativev/partial derivativen = u(m2)v(n2) on S-R x (0, T...

  10. Blow-up Estimates of the Positive Solution of a Parabolic System

    DEFF Research Database (Denmark)

    Pedersen, Michael; Zhigui, Lin

    1999-01-01

    This paper establishes the blowup estimates for the systems: $u_t-\\Delta u=0,$ $v_t-\\Delta v=0$ in $B_R\\times (0,T)$, $B_R\\subset\\Bbb R^n$, with the nonlinear boundary conditions $\\frac{\\partial u}{\\partial \\eta}=u^{m_1}v^{n_1}$ and $\\frac{\\partial v}{\\partial \\eta}=u^{m_2}v^{n_2}$ on $S_R\\times ...

  11. BLOW-UP ESTIMATES FOR A NON-NEWTONIAN FILTRATION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    杨作东; 陆启韶

    2001-01-01

    The prior estimate and decay property of positive solutions are derived for a system of quasi-linear elliptic differential equations first. Hence, the result of non-existence for differential equation system of radially nonincreasing positive solutions is implied. By using this non-existence result, blow-up estimates for a class quasi-linear reaction-diffusion systems (non-Newtonian filtration systems ) are established, which extends the result of semi- linear reaction- diffusion ( Fujita type ) systems .

  12. Acoustic streaming, fluid mixing, and particle transport by a Gaussian ultrasound beam in a cylindrical container

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Jeffrey S., E-mail: jeffm@cems.uvm.edu [School of Engineering, The University of Vermont, Burlington, Vermont 05405 (United States); Wu, Junru [Department of Physics, The University of Vermont, Burlington, Vermont 05405 (United States)

    2015-10-15

    A computational study is reported of the acoustic streaming flow field generated by a Gaussian ultrasound beam propagating normally toward the end wall of a cylindrical container. Particular focus is given to examining the effectiveness of the acoustic streaming flow for fluid mixing within the container, for deposition of particles in suspension onto the bottom surface, and for particle suspension from the bottom surface back into the flow field. The flow field is assumed to be axisymmetric with the ultrasound transducer oriented parallel to the cylinder axis and normal to the bottom surface of the container, which we refer to as the impingement surface. Reflection of the sound from the impingement surface and sound absorption within the material at the container bottom are both accounted for in the computation. The computation also accounts for thermal buoyancy force due to ultrasonic heating of the impingement surface, but over the time period considered in the current simulations, the flow is found to be dominated by the acoustic streaming force, with only moderate effect of buoyancy force.

  13. Acoustic streaming, fluid mixing, and particle transport by a Gaussian ultrasound beam in a cylindrical container

    International Nuclear Information System (INIS)

    A computational study is reported of the acoustic streaming flow field generated by a Gaussian ultrasound beam propagating normally toward the end wall of a cylindrical container. Particular focus is given to examining the effectiveness of the acoustic streaming flow for fluid mixing within the container, for deposition of particles in suspension onto the bottom surface, and for particle suspension from the bottom surface back into the flow field. The flow field is assumed to be axisymmetric with the ultrasound transducer oriented parallel to the cylinder axis and normal to the bottom surface of the container, which we refer to as the impingement surface. Reflection of the sound from the impingement surface and sound absorption within the material at the container bottom are both accounted for in the computation. The computation also accounts for thermal buoyancy force due to ultrasonic heating of the impingement surface, but over the time period considered in the current simulations, the flow is found to be dominated by the acoustic streaming force, with only moderate effect of buoyancy force

  14. Blow-up problems for the heat equation with a local nonlinear Neumann boundary condition

    Science.gov (United States)

    Yang, Xin; Zhou, Zhengfang

    2016-09-01

    This paper estimates the blow-up time for the heat equation ut = Δu with a local nonlinear Neumann boundary condition: The normal derivative ∂ u / ∂ n =uq on Γ1, one piece of the boundary, while on the rest part of the boundary, ∂ u / ∂ n = 0. The motivation of the study is the partial damage to the insulation on the surface of space shuttles caused by high speed flying subjects. We show the finite time blow-up of the solution and estimate both upper and lower bounds of the blow-up time in terms of the area of Γ1. In many other work, they need the convexity of the domain Ω and only consider the problem with Γ1 = ∂ Ω. In this paper, we remove the convexity condition and only require ∂Ω to be C2. In addition, we deal with the local nonlinearity, namely Γ1 can be just part of ∂Ω.

  15. Reconciling Particle-Beam and Optical Stopping-Power Measurements in Silicon

    Science.gov (United States)

    Karstens, William; Shiles, E. J.; Smith, David Y.

    A swift, charged particle passing through matter loses energy to electronic excitations via the electro-magnetic transients experienced by atoms along its path. Bethe related this process to the matter's frequency-dependent dielectric function ɛ (ℏω) through the energy-loss function, Im[-1/ ɛ (ℏω) ]. The matter's response may be summarized by a single parameter, the mean excitation energy, or I value, that combines the optical excitation spectrum and excitation probability. Formally, ln I is the mean of ln ℏω weighted by the energy-loss function. This provides an independent optical check on particle energy-loss experiments. However, a persistent disagreement is found for silicon: direct particle-beam studies yield 173.5elements suggests 165 eV. An independent determination from optical data in 1986 gave 174 eV supporting the higher values. However, recent x-ray measurements disclosed short comings in the 1986 optical data: 1. Measurements by Ershov and Lukirskii underestimated the L-edge strength, and 2. A power-law extrapolation overestimated the K-edge strength. We have updated these data and find I = 162 eV, suggesting that silicon's recommended I value should be reconsidered. While this 5% change in I value changes the stopping power by only 1%, it is significant for precision measurements with Si detectors. Supported in part by the US Department of Energy, Office of Science, Office of Nuclear Physics under Contract DE-AC02-06CH11357.

  16. Light beam attenuation and backscattering properties of particles in the Bohai Sea and Yellow Sea with relation to biogeochemical properties

    Science.gov (United States)

    Wang, Shengqiang; Qiu, Zhongfeng; Sun, Deyong; Shen, Xiaojing; Zhang, Hailong

    2016-06-01

    This study reports the first results of the variability in light beam attenuation and the backscattering properties of particles and their controlling factors during the summer in the Bohai Sea (BS) and Yellow Sea (YS), which are two typical shallow and semienclosed seas. We observe large variations in the particulate beam attenuation (cp) and backscattering coefficients (bbp); such variations are mainly attributed to changes in the total suspended matter, while the cross-sectional area concentration shows tighter relationships with both cp and bbp. The mass-specific beam attenuation (cp*) and backscattering coefficients (bbp*) vary more widely over about two orders of magnitude. The attenuation (Qce) and backscattering efficiencies (Qbbe) are important factors that control cp* and bbp*, which clearly separate all the samples into two types. Type 1 samples show low Qce and Qbbe and contain relatively high proportions of organic or large particles, while type 2 samples have high Qce and Qbbe and mainly contain relatively small mineral particles. The majority of the variability in cp* and bbp* within each type is related to the inverse of the product of particle apparent density (ρa) and mean diameter (DA); ρa plays a major role, while DA exerts only a slight impact. Overall, this study provides general knowledge of particulate beam attenuation and the backscattering properties in the BS and YS, which may improve our understanding of underwater radiative transfer processes, marine biogeochemical processes and ocean color algorithms.

  17. A test beam setup for the characterization of the Geiger-mode avalanche photodiode technology for particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Vilella, E., E-mail: evilella@el.ub.es [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Alonso, O. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Trenado, J. [Department of Structure and Constituents of Matter, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Vila, A.; Casanova, R. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Vos, M. [Instituto de Fisica Corpuscular (IFIC), C/Catedratico Jose Beltran 2, 46980 Paterna (Spain); Garrido, L. [Department of Structure and Constituents of Matter, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Dieguez, A. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain)

    2012-12-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite gain and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection still remains unexplored. In this contribution, we are going to expose different steps that we have taken in order to prove the efficiency of the Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present a setup for the characterization of these sensors in a test beam. The expected results of the test beam at DESY and CERN have been simulated with Geant4 and will also be exposed. -- Highlights: Black-Right-Pointing-Pointer A Setup for characterization of the GAPD technology in a test beam is presented. Black-Right-Pointing-Pointer Two test beams at DESY (6 GeV) and CERN (120 GeV) are already planned at current time. Black-Right-Pointing-Pointer A GAPD array has been designed and fabricated to fit the test beam requirements. Black-Right-Pointing-Pointer We have prepared a test beam setup to minimize the particle multiscattering. Black-Right-Pointing-Pointer The Expected results at DESY and CERN have been simulated with Geant4.

  18. 3d and r,z particle simulation of beams for heavy ion fusion: The WARP code

    International Nuclear Information System (INIS)

    WARP is an electrostatic particle-in-cell (PIC) code that is optimized for studies of space-charge-dominated beams. The authors use the code to understand a number of issues in HIF accelerators and transport systems, including: drift-compression in the presence of misalignments, axial confinement, longitudinal stability, transport around bends, and thermal equilibration processes. In this paper they describe the code architecture and numerical techniques employed to enhance efficiency. They then describe the new simple algorithm for following a beam around a bend, and recent results on bent-beam dynamics and transverse emittance evolution. Finally, they describe the code's most recent feature, a general-lattice capability structured to preserve the efficiency of the particle advance, and present initial results using it

  19. Vlasov's kinetic theory of the collective charged particle beam transport through a magnetized plasma in the strongly nonlocal regime

    International Nuclear Information System (INIS)

    Plasma-based accelerator schemes represent the first step of the research-development of the future accelerator machines. Within the Vlasov's kinetic theory, describing the plasma wake field interaction, the collective transport of a warm non-laminar relativistic charged particle beam is analyzed in the strongly nonlocal regime, where the beam spot-size is much less than the plasma wavelength. This is done in the overdense regime, i.e., the beam density is much less than the plasma density. The beam is supposed to be sufficiently long to experience the adiabatic shielding by the plasma. In these conditions, we neglect the longitudinal beam dynamics and focus on the transverse one only. We derive the virial description (envelope description) from the 2D Vlasov-Poisson-type system of equations that governs the transverse self-consistent plasma wake field excitation. The resulting envelope equation is then reduced, in the aberration-less approximation, to a differential equation for the beam spot size, where the role of the ambient magnetic field is evaluated in both laboratory and astrophysical environments. An analysis of the beam envelope self-modulation is then carried out and the criteria for the occurrence of the instability are found. (authors)

  20. Longitudinal beam stability in heavy ion storage rings

    International Nuclear Information System (INIS)

    This is an attempt to scale conditions for longitudinal beam stability to heavy ion storage rings (HIS) which have been proposed as part of some accelerator schemes to drive pellet fusion. The instability considered has been observed in many high intensity proton machines. In the CERN 25 GeV Proton Synchrotron (PS), this can occur near transition energy as well as during debunching at high energy. In the 30 GeV intersecting storage rings (ISR) similar effects happen to the newly injected beam when too many dense bunches are transferred. In all these cases the instability manifests itself by a rapid blow-up of the beam momentum spread and this blow-up is accompanied by rf activity observed on beam current pick-up electrodes at frequencies in the, say, 0.3 to 2 GHz region

  1. Beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.

    1994-12-01

    The term beam-beam effects is usually used to designate different phenomena associated with interactions of counter-rotating beams in storage rings. Typically, the authors speak about beam-beam effects when such interactions lead to an increase of the beam core size or to a reduction of the beam lifetime or to a growth of particle`s population in the beam halo and a correspondent increase of the background. Although observations of beam-beam effects are very similar in most storage rings, it is very likely that every particular case is largely unique and machine-dependent. This constitutes one of the problems in studying the beam-beam effects, because the experimental results are often obtained without characterizing a machine at the time of the experiment. Such machine parameters as a dynamic aperture, tune dependencies on amplitude of particle oscillations and energy, betatron phase advance between the interaction points and some others are not well known, thus making later analysis uncertain. The authors begin their discussion with demonstrations that beam-beam effects are closely related to non linear resonances. Then, they will show that a non linearity of the space charge field is responsible for the excitation of these resonances. After that, they will consider how beam-beam effects could be intensified by machine imperfections. Then, they will discuss a leading mechanism for the formation of the beam halo and will describe a new technique for beam tails and lifetime simulations. They will finish with a brief discussion of the coherent beam-beam effects.

  2. Tertiary particle production and target optimization of the H2 beam line in the SPS North Area

    CERN Document Server

    Tellander, Felix

    2016-01-01

    H2 beam line of SPS North Area is a high energy, high resolution and multipurpose particle beam line. It is able to transport secondary hadron and pure electron beams with momenta between 10 and 400 GeV/c to be exploited by several different experiments. In this work, tertiary particle production from a secondary target placed in the line is studied. The introduction of this “filter” target enhances the middle to low momentum hadron (20 - 60 GeV/c) and electron production. In this work, a systematic Monte Carlo simulation study using a GEANT 4 based package, G4beamline, has been performed in order to investigate the tertiary particle production from several different targets. More specifically, Cu, W and polyethylene targets with different thicknesses have been studied. The proton over pi+ ratio is of particular interest, as well as the optimal electron production for several momenta. The present work will act as a reference to be used by the future test-beam users of the line as an indication of the expe...

  3. Steering of sub-GeV charged particle beams by use of reflections in thin crystal targets

    CERN Document Server

    Bellucci, S; Chirkov, P N; Giannini, G; Maisheev, V A; Yazynin, I A

    2012-01-01

    The phenomenon of deflection of a charged particle beam due to channeling in a bent crystal has been well investigated and successfully applied for beam extraction at high-energy accelerators, for energies about 10 GeV and higher. However, it is of a big practical interest to consider the task of bending and extracting charged particles with energies below 1 GeV, for example, for production of ultrastable beams of low emittance for medical and biological applications. However, for low energy, i.e. below 1 GeV, the bent crystal channeling is not efficient. That motivates us to consider in this article an other crystal technique, based on thin straight crystal targets, as elements for the extraction and collimation of the circulating beam in an accelerator ring. The main advantages of reflection in straight crystals, in comparison with bent crystal channeling, consist in the small length of straight crystals along the beam, that reduces the amount of nuclear interactions and improves the background.

  4. Chromatic energy filter and characterization of laser-accelerated proton beams for particle therapy

    Science.gov (United States)

    Hofmann, Ingo; Meyer-ter-Vehn, Jürgen; Yan, Xueqing; Al-Omari, Husam

    2012-07-01

    The application of laser accelerated protons or ions for particle therapy has to cope with relatively large energy and angular spreads as well as possibly significant random fluctuations. We suggest a method for combined focusing and energy selection, which is an effective alternative to the commonly considered dispersive energy selection by magnetic dipoles. Our method is based on the chromatic effect of a magnetic solenoid (or any other energy dependent focusing device) in combination with an aperture to select a certain energy width defined by the aperture radius. It is applied to an initial 6D phase space distribution of protons following the simulation output from a Radiation Pressure Acceleration model. Analytical formula for the selection aperture and chromatic emittance are confirmed by simulation results using the TRACEWIN code. The energy selection is supported by properly placed scattering targets to remove the imprint of the chromatic effect on the beam and to enable well-controlled and shot-to-shot reproducible energy and transverse density profiles.

  5. The operation of the LHCb RICH photon detection system in a charged particle test beam

    CERN Document Server

    Brisbane, Sean

    2007-01-01

    The LHCb experiment at CERN employs two Ring Imaging Cherenkov (RICH) detectors to provide particle identification over the range 1 to 100 GeV/$c$. The RICH detectors use custom-built Hybrid Photon Detectors (HPDs) to detect the Cherenkov photons over the wavelength range 200-600 nm. Three colums of 16 HPDs with final readout electronics and data acquisition were installed in a prototype Cherenkov gas enclosure. Two gas radiators were studied, nitrogen and $C_{4}F_{10}$. Saturated Cherenkov rings ($\\beta \\approx$ 1) were focused onto the plane of HPDs by exposing the radiators to a beam of 80 GeV/$c$ charged pions from the CERN SPS, operated with a 25 ns bunch structure. The HPDs and the on- and off-detector electronics performed to specification, and the DAQ system was verified under the sustained 40 MHz readout mode required for LHC running. The analysis verified the local alignment across the HPDs and their relative timing. The photon yields from both radiators are in good agreement with expectations.

  6. Physics with gamma-beams and charged particle detectors: I) Nuclear structure II) Nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Gai, Moshe [LNS at Avery Point, University of Connecticut, Groton, CT 06340-6097, USA and Wright Lab, Dept. of Physics, Yale University, New Haven, CT 06520-8124 and the Charged Particle Working Group (CPWG) of the Technical Design Report (TDR) (United States)

    2015-02-24

    The Charged Particle Working Group (CPWG) is proposing to construct large area Silicon Strip Detector (SSD), a gas Time Projection Chamber detector read by an electronic readout system (eTPC) and a Bubble Chamber (BC) containing superheated high purity water to be used in measurements utilizing intense gamma-ray beams from the newly constructed ELI-NP facility at Magurele, Bucharest in Romania. We intend to use the SSD and eTPC detectors to address essential problems in nuclear structure physics, such as clustering and the many alpha-decay of light nuclei such as {sup 12}C and {sup 16}O. All three detectors (SSD, eTPC and BC) will be used to address central problems in nuclear astrophysics such as the astrophysical cross section factor of the {sup 12}C(α,γ) reaction and other processes central to stellar evolution. The CPWG intends to submit to the ELI-NP facility a Technical Design Report (TDR) for the proposed detectors.

  7. Method for extremal control of the beam parameters in charged particle accelerators

    International Nuclear Information System (INIS)

    The method of extremal control of charged particle beam parameters is suggested for the solution of the timization problem ophe IHEP boster operation mode. Motion along the estimation of drift direction with simultaneous adaptation to the value of drift rate is organized in the suggested method of extremal control. It is assumed that trajectory of the drift extremum can be approximated by the piecewise-linear function. Estimation of the drift direction is exercised on the base of fixation of two consequent positions of the extremum in the control space. The identification of the drift-direction are introduced in the algorithm of tracing the extrenum drift. Investigation of the method on the test two-dimensional square surface has shown that the method provides drift tracing within the rate of 0.01 a deg - 2 a deg where a deg - the initial working step of the stochastic approximation method. The average deviation does not exceed 0.7 a deg, and the accuracy of adaptation to the value of drift rate 10-3 K

  8. Trapping of quantum particles and light beams by switchable potential wells

    CERN Document Server

    Sonkin, Eduard; Granot, Er'el; Marchewka, Avi

    2010-01-01

    We consider basic dynamical effects in settings based on a pair of local potential traps that may be effectively switched on and off, or suddenly displaced, by means of appropriate control mechanisms, such as the scanning tunneling microscopy (STM) or photo-switchable quantum dots. The same models, based on the linear Schrodinger equation with time-dependent trapping potentials, apply to the description of optical planar systems designed for the switching of trapped light beams. The analysis is carried out in the analytical form, using exact solutions of the Schrodinger equation. The first dynamical problem considered in this work is the retention of a particle released from a trap which was suddenly turned off, while another local trap was switched on at a distance - immediately or with a delay. In this case, we demonstrate that the maximum of the retention rate is achieved at a specific finite value of the strength of the new trap, and at a finite value of the temporal delay, depending on the distance betwe...

  9. A Coordinated Focused Ion Beam/Ultramicrotomy Technique for Serial Sectioning of Hayabusa Particles and Other Returned Samples

    Science.gov (United States)

    Berger, E. L.; Keller, L. P.

    2014-01-01

    Recent sample return missions, such as NASA's Stardust mission to comet 81P/Wild 2 and JAXA's Hayabusa mission to asteroid 25143 Itokawa, have returned particulate samples (typically 5-50 µm) that pose tremendous challenges to coordinated analysis using a variety of nano- and micro-beam techniques. The ability to glean maximal information from individual particles has become increasingly important and depends critically on how the samples are prepared for analysis. This also holds true for other extraterrestrial materials, including interplanetary dust particles, micrometeorites and lunar regolith grains. Traditionally, particulate samples have been prepared using microtomy techniques (e.g., [1]). However, for hard mineral particles ?20 µm, microtome thin sections are compromised by severe chatter and sample loss. For these difficult samples, we have developed a hybrid technique that combines traditional ultramicrotomy with focused ion beam (FIB) techniques, allowing for the in situ investigation of grain surfaces and interiors. Using this method, we have increased the number of FIB-SEM prepared sections that can be recovered from a particle with dimensions on the order of tens of µms. These sections can be subsequently analyzed using a variety of electron beam techniques. Here, we demonstrate this sample preparation technique on individual lunar regolith grains in order to study their space-weathered surfaces. We plan to extend these efforts to analyses of individual Hayabusa samples.

  10. Particle Identification with Cherenkov detectors in the 2011 CALICE Tungsten Analog Hadronic Calorimeter Test Beam at the CERN SPS

    CERN Document Server

    Dannheim, D; Klempt, W; Lucaci Timoce, A; van der Kraaij, E

    2013-01-01

    In 2011 the CALICE Tungsten Analog Hadronic Calorimeter prototype (W-AHCAL) was exposed to mixed beams of electrons, pions, kaons and protons with momenta from 10 to 300 GeV in the CERN SPS H8 beam line. The selection of pion, kaon and proton samples is based on the information obtained from two Cherenkov threshold counters. This note presents the strategy for the particle identification, as well as the calibration, operation and analysis of the Cherenkov counters. Efficiency and sample-purity estimates are given for the data selected for the W-AHCAL data analysis.

  11. 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.

  12. DIPAC 2005 7. European workshop on beam diagnostics and instrumentation for particle accelerators

    International Nuclear Information System (INIS)

    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

  13. Can particle beam therapy be improved using helium ions? - a planning study focusing on pediatric patients.

    Science.gov (United States)

    Knäusl, Barbara; Fuchs, Hermann; Dieckmann, Karin; Georg, Dietmar

    2016-06-01

    Aim To explore the potential of scanned helium ion beam therapy ((4)He) compared to proton therapy in a comparative planning study focusing on pediatric patients. This was motivated by the superior biological and physical characteristics of (4)He. Material and methods For eleven neuroblastoma (NB), nine Hodgkin lymphoma (HL), five Wilms tumor (WT), five ependymoma (EP) and four Ewing sarcoma (EW) patients, treatment plans were created for protons and (4)He. Dose prescription to the planning target volume (PTV) was 21 Gy [relative biological effectiveness (RBE)] (NB), 19.8 Gy (RBE) (HL), 25.2 Gy (RBE) for the WT boost volume and 54 Gy (RBE) for EP and EW patients. A pencil beam algorithm for protons (constant RBE = 1.1) and (4)He was implemented in the treatment planning system Hyperion. For (4)He the relative biological effectiveness (RBE) was calculated with a 'zonal' model based on different linear energy transfer regions. Results Target constraints were fulfilled for all indications. For NB patients differences for kidneys and liver were observed for all dose-volume areas, except the high-dose volume. The body volume receiving up to 12.6 Gy (RBE) was reduced by up to 10% with (4)He. For WT patients the mean and high-dose volume for the liver was improved when using (4)He. For EP normal tissue dose was reduced using (4)He with 12.7% of the voxels receiving higher doses using protons. For HL and EW sarcoma patients the combination of large PTV volumes with the position of the organs at risk (OARs) obliterated the differences between the two particle species, while patients with the heart close to the PTV could benefit from (4)He. Conclusion Treatment plan quality improved with (4)He compared to proton plans, but advantages in OAR sparing were depending on indication and tumor geometries. These first results of scanned (4)He therapy motivate comprehensive research on (4)He, including acquisition of experimental data to improve modeling of (4)He. PMID

  14. Study of chemically synthesized ZnO nano particles under a bio template using radioactive ion beam

    CERN Multimedia

    This is a project proposal to study nano sized semiconductor ZnO system, useful in biology and medicinal purposes, using radioactive ion beam from ISOLDE. Doping of the nano particles with Cu, Cd and Ga ions (in their variable valancy states) are expected to impart changes in the electrical structure and properties in the said system under study. The morphological changes, chemical environment, micro structure, electrical and optical properties of the nano size particles of ZnO system (developed under a bio template of folic acid) after the interaction with radioactive ion beam will be studied. The provision of perturbed angular correlation (PAC) study with respect to the changes in chemical environment, where ever possible will be attempted.

  15. Investigation of the effects of intense pulsed particle beams on the durability of metal-to-plastic interfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Somuri V.; Renk, Timothy J.; Provencio, Paula Polyak; Petersen, Donald W. (University of Alabama, Birmingham, AL); Petersen, Thomas D. (University of California, San Diego, CA); Buchheit, Thomas Edward; McNulty, Donald E. (DePuy Orthopaedic, Inc., Warsaw, IN); Engelko, Vladimir (D. V. Efremov Scientific Research Institute of the Electrophysical Apparatus, St. Petersburg, Russia)

    2005-02-01

    We have investigated the potential for intense particle beam surface modification to improve the mechanical properties of materials commonly used in the human body for contact surfaces in, for example, hip and knee implants. The materials studied include Ultra-High Molecular Weight Polyethylene (UHMWPE), Ti-6Al-4Al (titanium alloy), and Co-Cr-Mo alloy. Samples in flat form were exposed to both ion and electron beams (UHMWPE), and to ion beam treatment (metals). Post-analysis indicated a degradation in bulk properties of the UHMWPE, except in the case of the lightest ion fluence tested. A surface-alloyed Hf/Ti layer on the Ti-6Al-4V is found to improve surface wear durability, and have favorable biocompatibility. A promising nanolaminate ceramic coating is applied to the Co-Cr-Mo to improve surface hardness.

  16. Global existence and blowup of solutions to a free boundary problem for mutualistic model

    Institute of Scientific and Technical Information of China (English)

    KIM; KwangIk

    2010-01-01

    This article is concerned with a system of semilinear parabolic equations with a free boundary,which arises in a mutualistic ecological model.The local existence and uniqueness of a classical solution are obtained.The asymptotic behavior of the free boundary problem is studied.Our results show that the free problem admits a global slow solution if the inter-specific competitions are strong,while if the inter-specific competitions are weak there exist the blowup solution and global fast solution.

  17. On the Blow-up Criterion of Smooth Solutions to the MHD System in BMO Space

    Institute of Scientific and Technical Information of China (English)

    Bao-quan Yuan

    2006-01-01

    In this paper we study the blow-up criterion of smooth solutions to the incompressible magnetohydrodynamics system in BMO space. Let (u(x,t),b(x,t)) be smooth solutions in (0, T). It is shown that the solution (u(x, t), b(x, t)) can be extended beyond t = T if (u(x, t), b(x, t)) ∈ L1(0, T; BMO) or the vorticity(rot u(x, t), rot b(x, t)) ∈ L1 (0, T; BMO) or the deformation (Def u(x, t), Def b(x, t)) ∈ L1 (0, T; BMO).

  18. A class of blowup and global analytical solutions of the viscoelastic Burgers' equations

    Energy Technology Data Exchange (ETDEWEB)

    An, Hongli, E-mail: hongli.an@connect.polyu.hk [College of Science, Nanjing Agricultural University, Nanjing 210095 (China); Cheung, Ka-Luen, E-mail: kaluen@ied.edu.hk [Department of Mathematics and Information Technology, The Hong Kong Institute of Education, 10 Po Ling Road, Tai Po, New Territories (Hong Kong); Yuen, Manwai, E-mail: nevetsyuen@hotmail.com [Department of Mathematics and Information Technology, The Hong Kong Institute of Education, 10 Po Ling Road, Tai Po, New Territories (Hong Kong)

    2013-11-08

    In this Letter, by employing the perturbational method, we obtain a class of analytical self-similar solutions of the viscoelastic Burgers' equations. These solutions are of polynomial-type whose forms, remarkably, coincide with that given by Yuen for the other physical models, such as the compressible Euler or Navier–Stokes equations and two-component Camassa–Holm equations. Furthermore, we classify the initial conditions into several groups and then discuss the properties on blowup and global existence of the corresponding solutions, which may be readily seen from the phase diagram.

  19. Critical Blow-Up and Global Existence for Discrete Nonlinear p-Laplacian Parabolic Equations

    Directory of Open Access Journals (Sweden)

    Soon-Yeong Chung

    2014-01-01

    Full Text Available The goal of this paper is to investigate the blow-up and the global existence of the solutions to the discrete p-Laplacian parabolic equation utx,t=Δp,wux,t+λux,tp-2ux,t, x,t∈S×0,∞, ux,t=0, x,t∈∂S×0,∞, ux,0=u0, depending on the parameters p>1 and λ>0. Besides, we provide several types of the comparison principles to this equation, which play a key role in the proof of the main theorems. In addition, we finally give some numerical examples which exploit the main results.

  20. PREFACE: 1st Conference on Light and Particle Beams in Materials Science 2013 (LPBMS2013)

    Science.gov (United States)

    Kumai, Reiji; Murakami, Youichi

    2014-04-01

    From 29-31 August 2013, the 1st International Conference on Light and Particle Beams in Materials Science, LPBMS 2013, took place in the Tsukuba International Congress Center in the city of Tsukuba, Japan. The conference was a continuation of the international series Synchrotron Radiation in Materials Science (SRMS), which started in 1994. The last one, SRMS-7, was held in Oxford UK 11-14 July 2010, where the International Advisory Committee (IAC) recommended the conference be enlarged to incorporate Materials Research from Neutron, Muon, and Slow Positron Sources, as well as the science emerging from Synchrotron Light Sources. The conference brought together contributions from academics and industrial researchers with a diverse background and experience from the physics, chemistry and engineering communities. The topics covered in the LPBMS2013 include strongly correlated electron systems, magnetism and magnetic materials, soft matter, interface and surface defects, catalysts, biomaterials, and ceramics. In the 3-day scientific program, the conference consisted of 9 plenary talks, 33 invited talks, 20 oral presentations, and 126 poster presentations. We are pleased to publish the proceedings of the LPBMS2013 in this volume of Journal of Physics: Conference Series. This volume contains 58 papers representing the work that was presented and discussed at the conference. We hope that this volume will promote further development of this interdisciplinary materials research emerging from synchrotron light, neutron, muon, and slow positron sciences. Finally, we would like to thank the International Advisory Committee (Chair: Professor G N Greaves), sponsors, all the participants and contributors for making possible this international meeting of researchers. Reiji Kumai & Youichi Murakami Conference photograph Details of the program and organizing committees are available in the pdf

  1. Role of cathode identity in liquid chromatography particle beam glow discharge mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, M.V. Balarama [Department of Chemistry, Biosystems Research Complex, Clemson University, Clemson, SC 29634-1905 (United States); Marcus, R.K. [Department of Chemistry, Biosystems Research Complex, Clemson University, Clemson, SC 29634-1905 (United States)], E-mail: marcusr@clemson.edu

    2008-06-15

    A detailed evaluation of the role of cathode identity on the analytical and spectral characteristics of various organic, organometallic and metal analytes using liquid chromatography-particle beam/glow discharge mass spectrometry (LC-PB/GDMS) has been carried out. A d.c. discharge, operating with argon as the support gas, was used throughout this work. In this study, Cu which has a relatively high sputtering rate, Ni which has moderate sputtering rate and Ta which has very low sputtering rate, are taken as cathode materials to study the ionization, fragmentation, and analytical characteristics of organic (caffeine, epigallocatechin gallate, peptide as representative compounds), organometallic (selenomethionine, triethyl lead chloride as representative compounds) and metal (Fe, La, Cs and Pb) species. A range of discharge gas pressures (26.6-106.4 Pa) and currents (0.2-1.5 mA) were investigated with the test cathodes to determine their influence on the spectral composition and overall analytical response for the various test species. Calibration plots were obtained for all of the species for each of the three cathodes to determine the respective limits of detection. Relative detection limits in the range of 0.02 to 15 ng mL{sup -1} (0.002-1.5 ng, absolute) for the test species were found to be in the order of Cu > Ni > Ta; which follows the order of the sputtering characteristics of the respective cathodes. These studies rendered information about the respective discharge parameters' role in choosing the most appropriate cathode identity in PB-GDMS for application in the areas of organic, organometallic and inorganic species analysis.

  2. Manufacturing and characterization of bent silicon crystals for studies of coherent interactions with negatively charged particles beams

    International Nuclear Information System (INIS)

    Efficient steering of GeV-energy negatively charged particle beams was demonstrated to be possible with a new generation of thin bent silicon crystals. Suitable crystals were produced at the Sensor Semiconductor Laboratory of Ferrara starting from Silicon On Insulator wafers, adopting proper revisitation of silicon micromachining techniques such as Low Pressure Chemical Vapor Deposition, photolithography and anisotropic chemical etching. Mechanical holders, which allow to properly bend the crystal and to reduce unwanted torsions, were employed. Crystallographic directions and crystal holder design were optimized in order to excite quasi-mosaic effect along (1 1 1) planes. Prior to exposing the crystal to particle beams, a full set of characterizations were performed. Infrared interferometry was used to measure crystal thickness with high accuracy. White-light interferometry was employed to characterize surface deformational state and its torsion. High-resolution X-rays diffraction was used to precisely measure crystal bending angle along the beam. Manufactured crystals were installed and tested at the MAMI MAinz MIcrotron to steer sub-GeV electrons, and at SLAC to deflect an electron beam in the 1 to 10 GeV energy range

  3. Manufacturing and characterization of bent silicon crystals for studies of coherent interactions with negatively charged particles beams

    Energy Technology Data Exchange (ETDEWEB)

    Germogli, G.; Mazzolari, A.; Bandiera, L.; Bagli, E.; Guidi, V.

    2015-07-15

    Efficient steering of GeV-energy negatively charged particle beams was demonstrated to be possible with a new generation of thin bent silicon crystals. Suitable crystals were produced at the Sensor Semiconductor Laboratory of Ferrara starting from Silicon On Insulator wafers, adopting proper revisitation of silicon micromachining techniques such as Low Pressure Chemical Vapor Deposition, photolithography and anisotropic chemical etching. Mechanical holders, which allow to properly bend the crystal and to reduce unwanted torsions, were employed. Crystallographic directions and crystal holder design were optimized in order to excite quasi-mosaic effect along (1 1 1) planes. Prior to exposing the crystal to particle beams, a full set of characterizations were performed. Infrared interferometry was used to measure crystal thickness with high accuracy. White-light interferometry was employed to characterize surface deformational state and its torsion. High-resolution X-rays diffraction was used to precisely measure crystal bending angle along the beam. Manufactured crystals were installed and tested at the MAMI MAinz MIcrotron to steer sub-GeV electrons, and at SLAC to deflect an electron beam in the 1 to 10 GeV energy range.

  4. Alpha particle diagnostic beam line system to generate an intense Li0 beam with an ORNL SITEX source

    International Nuclear Information System (INIS)

    The Oak Ridge National Laboratory (ORNL) SITEX (Surface Ionization with Transverse Extraction) negative ion source utilizes a 100-V/20-A reflex arc discharge in a 1300-gauss magnetic field to generate Cs+ ions and H+ or D+ ions, depending on the beam required. A shaped molybdenum plate is placed directly behind the arc column. Cesium coverage on this plate is used to minimize the surface work function, which requires two-thirds of a monolayer coverage. Cesium coverage ia adjusted both by cesium flow control into the arc discharge chamber and by temperature control of the converter using gaseous-helium cooling channels in the converter plate. Normal converter operational temperatures are 3000 to 5000C H-/D- beams are generated at the biased converter surface (-150 V with respect to the anode) by Cs+ sputtering of absorbed hydrogen or deuterium and by the reflection-conversion mechanism of H+/D+ ions which strike the converter surface at 150 eV. The negative ions are accelerated through the 150-V plasma sheath at the converter surface and are focused by the converter geometry and magnetic field so as to pass through the exit aperture with minimum angular divergence. The ion optics of the SITEX accelerator has been calculated using the ORNL 3-D optics code and results in a divergence perpendicular to the slot of theta/sub perpendicular rms/ = 0.350 and parallel to the slot of theta/sub parallel rms/ = 0.180. This beam divergence should be adequate for injection into a radio frequency quadrupole (RFQ) for further acceleration

  5. A method of particle transport study using supersonic molecular beam injection and microwave reflectometry on HL-2A tokamak

    International Nuclear Information System (INIS)

    A method of the particle transport study using supersonic molecular beam injection (SMBI) and microwave reflectometry is reported in this paper. Experimental results confirm that pulsed SMBI is a good perturbation source with deeper penetration and better localization than the standard gas puffing. The local density modulation is induced using the pulsed SMBI and the perturbation density is measured by the microwave reflectometry. Using Fourier transform analysis for the local density perturbation, radial profiles of the amplitude and phase of the density modulation can be obtained. The experimental results in HL-2A show that the particle injected by SMBI is located at about r/a=0.65-0.75. The position of the main particle source can be determined through three aspects: the minimum of the phase of the first harmonic of the Fourier transform of the modulated density measured by microwave reflectometry; the Ha intensity profile and the local density increase ratio. The maximum of the amplitude of the first harmonic shifts often inward relative to the particle source location, which indicates clearly there is an inward particle pinch in this area. Good agreement has been found between the experimental results and the simulation using analytical transport model. The particle diffusivity D and the particle convection velocity V have been obtained by doing this simulation. The sensitivity in the transport coefficients of the amplitude and the phase of the density modulation has been discussed.

  6. High energy backward-Compton scattering γ beam for particle and nuclear physics

    International Nuclear Information System (INIS)

    The GeV photon beam at SPring-8 is produced by backward-Compton scattering of laser photons from 8 GeV electrons. The maximum energy of the photon will be above 3 GeV, and the beam intensity will be 107 photons/sec. Polarization of the photon beam will be 100% at the maximum energy with fully polarized laser photons. We report the outline of the quark nuclear physics project with this high-quality high-intensity beam. (author)

  7. Ion beam analysis techniques for the elemental fingerprinting of fine particle smoke from vegetation burning in NSW

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, D. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator based ion beam analysis (IBA) techniques, including PIXE, PIGME, RBS and PESA, have been used to analyse elemental compositions of airborne particles covering a 60,000 square kilometres area of Wollongong, Sydney and Newcastle. These IBA techniques provide elemental concentrations for over 20 different elements from hydrogen to lead, they include H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Br and Pb. The four ion beam techniques are performed simultaneously on the 3MV Van de Graaff accelerator at ANSTO and have been described in detail elsewhere. They are sufficiently sensitive to analyse for many of these elements to levels around 10 ng/m{sup 3} or less in about five minutes of accelerator running time per filter. This is more than adequate for aerosol analyses as most filters contain around 150 {mu}g/cm{sup 2} of material which corresponds to about 10{mu}g/m{sup 3} of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5{mu}m. Fine particle data has been collected twice a week and analysed for each of the above elements by ANSTO since 1991 at more than 25 different sites throughout NSW. This large dataset set allows us to not only determine the composition of fine particles and to look for signature elements for particular sources but also to use multivariate statistics to define elemental source fingerprints and then to determine the percentage contributions of these fingerprints to the total fine particle mass in the atmosphere. This paper describes the application of these techniques to the study of domestic wood fires and vegetation burning in NSW over a two year period from 1992-93. It also presents, for the first time, fine particle data related to the January 1994 bushfires in NSW. 6 refs., 1 tab., 5 figs.

  8. Secondary radiation measurements for particle therapy applications: nuclear fragmentation produced by $^4$He ion beams in a PMMA target

    CERN Document Server

    Marafini, M; Pinci, D; Battistoni, G; Collamati, F; De Lucia, E; Faccini, R; Frallicciardi, P M; Mancini-Terracciano, C; Mattei, I; Muraro, S; Piersanti, L; Rovituso, M; Rucinski, A; Russomando, A; Sarti, A; Sciubba, A; Camillocci, E Solfaroli; Toppi, M; Traini, G; Voena, C; Patera, V

    2016-01-01

    Nowadays there is a growing interest in Particle Therapy treatments exploiting light ion beams against tumors due to their enhanced Relative Biological Effectiveness and high space selectivity. In particular promising results are obtained by the use of $^4$He projectiles. Unlike the treatments performed using protons, the beam ions can undergo a fragmentation process when interacting with the atomic nuclei in the patient body. In this paper the results of measurements performed at the Heidelberg Ion-Beam Therapy center are reported. For the first time the absolute fluxes and the energy spectra of the fragments - protons, deuterons, and tritons - produced by $^4$He ion beams of 102, 125 and 145 MeV/u energies on a poly-methyl methacrylate target were evaluated at different angles. The obtained results are particularly relevant in view of the necessary optimization and review of the Treatment Planning Software being developed for clinical use of $^4$He beams in clinical routine and the relative benchmarking of ...

  9. A Method for Real Time Monitoring of Charged Particle Beam Profile and Fluence

    CERN Document Server

    Palni, Prabhakar; Taylor, Aaron; Vora, Sandip; McDuff, Haley; Gu, Qufei; Seidel, Sally

    2013-01-01

    Detectors planned for use at the Large Hadron Collider will operate in a radiation field produced by beam collisions. To predict the radiation damage to the components of the detectors, prototype devices are irradiated at test beam facilities that reproduce the radiation conditions expected. The profile of the test beam and the fluence applied per unit time must be known. Techniques such as thin metal foil activation and radiographic image analysis have been used to measure these; however, some of these techniques do not operate in real time, have low sensitivity, or have large uncertainties. We have developed a technique to monitor in real time the beam profile and fluence using an array of $p-i-n$ semiconductor diodes whose forward voltage is linear with fluence over the fluence regime relevant to, for example, tracking in the LHC Upgrade era. We have demonstrated this technique in the 800 MeV proton beam at the LANSCE facility of Los Alamos National Laboratory.

  10. Literature file on 'fast kickers and septa', componenets for deflection and separation of particle beams

    International Nuclear Information System (INIS)

    The File consists of classified and numbered articles from the literature on the following subjects: 1 - Kickers: fast switching (electro-)magnetic or electrostatic components for small deflection; 2 - Septum Magnets: both small and great deflecting components, with the purpose to create or bridge over space between the deflected beam and the other, unperturbed beam; 3 - Electrostatic Septa: low loss, beam splitting components which give small deflection for the extracted part of the beam and no perturbation for the rest of the beam. The articles have been classified per institute or laboratory, eventually with further classification per project. The classified articles are then numbered chronologically. Extension of the File is still possible. The contents of the articles are summarized by means of catchwords. Specifications of the described kickers, septum magnets and electrostatic septa are represented in a tabular form

  11. Blow-up in multidimensional aggregation equations with mildly singular interaction kernels

    Science.gov (United States)

    Bertozzi, Andrea L.; Carrillo, José A.; Laurent, Thomas

    2009-03-01

    We consider the multidimensional aggregation equation ut - ∇· (u∇K * u) = 0 in which the radially symmetric attractive interaction kernel has a mild singularity at the origin (Lipschitz or better). In the case of bounded initial data, finite time singularity has been proved for kernels with a Lipschitz point at the origin (Bertozzi and Laurent 2007 Commun. Math. Sci. 274 717-35), whereas for C2 kernels there is no finite-time blow-up. We prove, under mild monotonicity assumptions on the kernel K, that the Osgood condition for well-posedness of the ODE characteristics determines global in time well-posedness of the PDE with compactly supported bounded nonnegative initial data. When the Osgood condition is violated, we present a new proof of finite time blow-up that extends previous results, requiring radially symmetric data, to general bounded, compactly supported nonnegative initial data without symmetry. We also present a new analysis of radially symmetric solutions under less strict monotonicity conditions. Finally, we conclude with a discussion of similarity solutions for the case K(x) = |x| and some open problems. This paper is published as part of a collection in honour of Todd Dupont's 65th birthday.

  12. The effect of non-extensive particles on slowing down and diffusion of a particle's beam in the plasma

    Science.gov (United States)

    Ebne Abbasi, Z.; Esfandyari-Kalejahi, A.

    2016-07-01

    The slowing down as well as the deflection time of test particles in the plasma is studied in the non-extensive statistics. The relevant relations are derived using Fokker Planck equation. It is remarked that the slowing down and deflection times modify considerably in the non-extensive statistics in comparison with Boltzmann Gibbs one. It is found that by decreasing non-extensivity index q ( 1 / 3 sub-extensive particles, the same results are obtained by decreasing q. Additionally, the effects of non-extensive distributed particles on the electrical conductivity and diffusion coefficient of plasma are studied. It is shown that plasmas with smaller qs are better conductors in both 1 / 3 sub-extensive particles. Moreover, it is found that the diffusion coefficient across a magnetic field is decreased by decreasing q. Furthermore, our results reduce to the solutions of Maxwellian plasma at the extensive limit q → 1. This research will be helpful in understanding the relaxation times and transport properties of fusion and astrophysical plasmas.

  13. EFFECT OF PARTICLE SIZE AND PACKING RATIO OF PID ON VIBRATION AMPLITUDE OF BEAM

    OpenAIRE

    P.S. Kachare; Bimleshkumar

    2013-01-01

    Everything in the universe that has mass possesses stiffness and intrinsic damping. Owing to the stiffness property, mass will vibrate when excited and its intrinsic damping property will act to stop the vibration. The particle impact damper (PID) is a very interesting damper that affects impact and friction effects of particles by means of energy dissipation. PID is a means for achieving high structural damping by using a particle-filled enclosure attached to a structure. The particles absor...

  14. An online calorimeter trigger for removing outsiders from particle beam calibration tests

    CERN Document Server

    Damazio, D O

    2003-01-01

    An online neural triggering system for particle identification is presented. It is developed for calibration tests with Tilecal, the hadronic calorimeter of the ATLAS experiment. The proposed neural system proves to cope with the required data input rate and achieves more than 99.7% in particle classification efficiency, even when significant particle contamination is observed in the data samples.

  15. Secondary radiation measurements for particle therapy applications: Charged secondaries produced by 4He and 12C ion beams in a PMMA target at large angle

    CERN Document Server

    Rucinski, A; Battistoni, G; Collamati, F; Faccini, R; Frallicciardi, P M; Mancini-Terracciano, C; Marafini, M; Mattei, I; Muraro, S; Paramatti, R; Piersanti, L; Pinci, D; Russomando, A; Sarti, A; Sciubba, A; Camillocci, E Solfaroli; Toppi, M; Traini, G; Voena, C; Patera, V

    2016-01-01

    Measurements performed with the purpose of characterizing the charged secondary radiation for dose release monitoring in particle therapy are reported. Charged secondary yields, energy spectra and emission profiles produced in poly-methyl methacrylate (PMMA) target by 4He and 12C beams of different therapeutic energies were measured at 60 and 90 degree with respect to the primary beam direction. The secondary yields of protons produced along the primary beam path in PMMA target were obtained. The energy spectra of charged secondaries were obtained from time-of-flight information, whereas the emission profiles were reconstructed exploiting tracking detector information. The measured charged secondary yields and emission profiles are in agreement with the results reported in literature and confirm the feasibility of ion beam therapy range monitoring using 12C ion beam. The feasibility of range monitoring using charged secondary particles is also suggested for 4He ion beam.

  16. Compact and high-particle-flux thermal-lithium-beam probe system for measurement of two-dimensional electron density profile.

    Science.gov (United States)

    Shibata, Y; Manabe, T; Kajita, S; Ohno, N; Takagi, M; Tsuchiya, H; Morisaki, T

    2014-09-01

    A compact and high-particle-flux thermal-lithium-beam source for two-dimensional measurement of electron density profiles has been developed. The thermal-lithium-beam oven is heated by a carbon heater. In this system, the maximum particle flux of the thermal lithium beam was ~4 × 10(19) m(-2) s(-1) when the temperature of the thermal-lithium-beam oven was 900 K. The electron density profile was evaluated in the small tokamak device HYBTOK-II. The electron density profile was reconstructed using the thermal-lithium-beam probe data and this profile was consistent with the electron density profile measured with a Langmuir electrostatic probe. We confirm that the developed thermal-lithium-beam probe can be used to measure the two-dimensional electron density profile with high time and spatial resolutions.

  17. Particle beam radiation therapy using carbon ions and protons for oligometastatic lung tumors

    International Nuclear Information System (INIS)

    A study was undertaken to analyze the efficacy and feasibility of particle beam radiation therapy (PBRT) using carbon ions and protons for the treatment of patients with oligometastatic lung tumors. A total of 47 patients with 59 lesions who underwent PBRT for oligometastatic lung tumors between 2003 and 2011 were included in this study. Patient median age was 66 (range, 39–84) years. The primary tumor site was the colorectum in 11 patients (23.4%), lung in 10 patients (21.3%) and a variety of other sites in 26 patients (55.3%). Thirty-one patients (66%) received chemotherapy prior to PBRT. Thirty-three lesions were treated with 320-MeV carbon ions and 26 were treated with 150- or 210-Mev protons in 1–4 portals. A median total dose of 60 (range, 52.8–70.2) GyE was delivered at the isocenter in 8 (range, 4–26) fractions. The median follow-up time was 17 months. The local control, overall survival and progression-free survival rates at 2 years were 79%, 54 and 27% respectively. PBRT-related toxicities were observed; six patients (13%) had grade 2 toxicity (including grade 2 radiation pneumonitis in 2) and six patients (13%) had grade 3 toxicity. Univariate analysis indicated that patients treated with a biologically equivalent dose of 10 (BED10) <110 GyE10, had a significantly higher local recurrence rate. Local control rates were relatively lower in the subsets of patients with the colorectum as the primary tumor site. No local progression was observed in metastases from colorectal cancer irradiated with a BED10 ≥ 110 GyE10. There was no difference in treatment results between proton and carbon ion therapy. PRBT is well tolerated and effective in the treatment of oligometastatic lung tumors. To further improve local control, high-dose PBRT with a BED10 ≥ 110 GyE10 may be promising. Further investigation of PBRT for lung oligometastases is warranted

  18. Blow-up of solutions for the sixth-order thin film equation with positive initial energy

    Indian Academy of Sciences (India)

    Wenjun Liu; Kewang Chen

    2015-10-01

    In this paper, a sixth-order parabolic thin film equation with the initial boundary condition is considered. By using the improved energy estimate method and by constructing second-order elliptic problem, a blow-up result for certain solution with positive initial energy is established, which is an improve over the previous result of Li and Liu.

  19. The Blow-up Rate for Positive Solutions of Indefinite Parabolic Problems and Related Liouville Type Theorems

    Institute of Scientific and Technical Information of China (English)

    Ruixiang XING

    2009-01-01

    In this paper,we derive an upper bound estimate of the blow-up rate for positive solutions of indefinite parabolic equations from Liouville type theorems. We also use moving plane method to prove the related Liouville type theorems for semilinear parabolic problems.

  20. GLOBAL EXISTENCE AND BLOW-UP OF SOLUTIONS TO A NONLOCAL EVOLUTION p-LAPLACE SYSTEM WITH NONLINEAR BOUNDARY CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    Wu Xuesong; Gao Wenjie; Cao Jianwen

    2011-01-01

    In this paper, the authors discuss the global existence and blow-up of the solution to an evolution ρ-Laplace system with nonlinear sources and nonlinear boundary condition. The authors first establish the local existence of solutions, then give a necessary and sufficient condition on the global existence of the positive solution.

  1. 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...

  2. Secondary radiation measurements for particle therapy applications: prompt photons produced by $^{4}$He, $^{12}$C and $^{16}$O ion beams in a PMMA target

    OpenAIRE

    Mattei, Ilaria; Collamati, Francesco; De Lucia, Erika; Faccini, Riccardo; Frallicciardi, Paola Maria; Mancini-Terracciano, Carlo; Marafini, Michela; Muraro, Silvia; Paramatti, Riccardo; Patera, Vincenzo; Piersanti, Luca; Pinci, Davide; Rucinski, Antoni; Russomando, Andrea; Sarti, Alessio

    2016-01-01

    Charged particle beams are used in Particle Therapy (PT) to treat oncological patients due to their selective dose deposition in tissues and to their high biological effect in killing cancer cells with respect to photons and electrons used in conventional radiotherapy. Nowadays, protons and carbon ions are used in PT clinical routine but, recently, the interest on the potential application of helium and oxygen beams is growing due to their reduced multiple scattering inside the body and incre...

  3. Third-order TRANSPORT: A computer program for designing charged particle beam transport systems

    International Nuclear Information System (INIS)

    TRANSPORT has been in existence in various evolutionary versions since 1963. The present version of TRANSPORT is a first-, second-, and third-order matrix multiplication computer program intended for the design of static-magnetic beam transport systems. This report discusses the following topics on TRANSPORT: Mathematical formulation of TRANSPORT; input format for TRANSPORT; summaries of TRANSPORT elements; preliminary specifications; description of the beam; physical elements; other transformations; assembling beam lines; operations; variation of parameters for fitting; and available constraints -- the FIT command

  4. Third-order TRANSPORT: A computer program for designing charged particle beam transport systems

    Energy Technology Data Exchange (ETDEWEB)

    Carey, D.C. [Fermi National Accelerator Lab., Batavia, IL (United States); Brown, K.L.; Rothacker, F. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1995-05-01

    TRANSPORT has been in existence in various evolutionary versions since 1963. The present version of TRANSPORT is a first-, second-, and third-order matrix multiplication computer program intended for the design of static-magnetic beam transport systems. This report discusses the following topics on TRANSPORT: Mathematical formulation of TRANSPORT; input format for TRANSPORT; summaries of TRANSPORT elements; preliminary specifications; description of the beam; physical elements; other transformations; assembling beam lines; operations; variation of parameters for fitting; and available constraints -- the FIT command.

  5. Tertiary particle production and target optimization of the H2 beam line in the SPS North Area

    CERN Document Server

    Charitonidis, Nikolaos; CERN. Geneva. ATS Department

    2016-01-01

    In this note, the tertiary particle yield from secondary targets of different materials placed at the ‘filter’ position of the H2 beam line of SPS North Area are presented. The production is studied for secondary beams of different momenta in the range of 50-250 GeV/c. More specifically, we studied six different targets: two copper cylinders with a radius of 40 mm and lengths of 100 and 300 mm, one solid tungsten cylinder with a radius of 40 mm and a length of 150 mm and three polyethylene cylinders with radius of 40 mm and lengths of 550, 700 and 1000 mm. Eight different momenta of the secondary beam (50, 60, 70, 100, 120, 150, 200 and 250 GeV/c) as well as two different physics lists (QGSP_BIC and FTFP_BERT) have been extensively studied. The purpose of this study is (a) to optimize (using the appropriate filter target) the particle production from the secondary targets as demanded by the experiments (b) investigate the proton production (with respect to the pion production) in the produced tertiary bea...

  6. Radiological physics of heavy charged-particle beams used for therapy

    International Nuclear Information System (INIS)

    The beams available for biological investigations at the Bevatron or at the Bevalac range from helium to iron ions. However, only carbon, neon, and argon beams have been used for therapy. The treatment techniques are arbitrarily divided into two categories: small field and large field irradiation. Examples of the small field treatments are pituitary irradiation, which generaly utilizes the plateau portion of the helium depth-dose curve, and treatment of ocular melanoma, which uses a modified Bragg peak of the helium beam. Large field treatments for cancer therapy generally requires a beam that has a large uniform transverse profile and a modified Bragg peak. Procedures and instrumentation for patient irradiations at the Bevatron/Bevalac have been based on the prior experience obtained at the 184-inch Synchrocyclotron, and for that reason both facilities are discussed

  7. Advanced development of particle beam probe diagnostic systems. Technical progress report, June 1, 1982-October 31, 1983

    International Nuclear Information System (INIS)

    The primary objective of this program is the advanced development of sophisticated particle beam diagnostic techniques for making space and time resolved measurements on high temperature magnetically confined plasmas. The procedure is to develop and test new techniques on small-scale laboratory experiments and then transfer the technology to mainline confinement experiments. During the period covered by this progress report the major advances were: (1) demonstrated that beam probing can provide simultaneous measurements of n, phi and T/sub e/ on plasmas when T/sub e/ is less than approximately 500 eV; (2) demonstrated simultaneous measurements of n tilde and phi tilde on tokamak geometry for frequencies below 200 kHz; (3) developed the concept of multi-element energy analyzer to provide simultaneous measurements for more than one spatial location in the plasma; and (4) carried out preliminary analysis that showed that beam probes can be implemented on complex magnetic geometries such as ATF and that beam probe system could be extended into the MeV energy range

  8. A test beam set-up for the characterization of the Geiger-mode avalanche photodiode technology for particle tracking

    CERN Document Server

    Vilella, A; Trenado, J; Vila, A; Casanova, R; Vos, M; Garrido, L; Dieguez, A

    2012-01-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite gain and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection still remains unexplored. In this contribution, we are going to expose different steps that we have taken in order to prove the efficiency of the Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present a setup for the characterization of these sensors in a test beam. The expected results of the test beam at DESY and CERN have been simulated with Geant4 and will also be exposed.

  9. Resistance of Bacillus subtilis spores to 12C ion beams, stimulation of high-energy charged particles in space

    Science.gov (United States)

    Zhang, Li; Dang, Bingrong; Li, Junxiong; Chen, Jinsong; Liu, Mei; Liu, Zhiheng; Zhang, Lixin

    To monitor the response of live microbes in space radiation environment with high-energy charged particles, we carry out ground stimulation radiation experiments. Spores of Bacillus (CGMCC 1.1849) species are one of the model systems used for astro- and radiobiological studies. (12) C ion beams served as stimulated space radiation from 5gry, 10gry, 20gry, 40gry, to 80gry at a rate of 15gry/min Death rates are measured and mutant strains are isolated. Five representative strains are analyzed for their corresponding gene sequences, protein sequences and gene expression index of DNA repair system gene recA and recO. The statistic results showed the strains resistance to (12) C ion beams radiation is partially due to the increase of gene expression index of recA and recO. In conclusion, our research provide a surrogate system to monitor the live microbial response in resistant to space radiation environment.

  10. Use of the Kalman filter in signal processing to reduce beam requirements for alpha-particle diagnostics

    International Nuclear Information System (INIS)

    Several techniques proposed for diagnosing the velocity distribution of fast alpha-particles in a burning plasma require the injection of a beam of fast neutral atoms as probes. The author discusses how improving signal detection techniques is a high leverage factor in reducing the cost of the diagnostic beam. Optimal estimation theory provides a computational algorithm, the Kalman filter, that can optimally estimate the amplitude of a signal with arbitrary (but known) time dependence in the presence of noise. In one example presented, based on a square-wave signal and assumed noise levels, the Kalman filter achieves an enhancement of signal detection efficiency of about a factor of 10 (as compared with the straightforward observation of the signal superimposed on noise) with an observation time of 100 signal periods

  11. ADVANCED METHODS FOR THE COMPUTATION OF PARTICLE BEAM TRANSPORT AND THE COMPUTATION OF ELECTROMAGNETIC FIELDS AND MULTIPARTICLE PHENOMENA

    Energy Technology Data Exchange (ETDEWEB)

    Alex J. Dragt

    2012-08-31

    Since 1980, under the grant DEFG02-96ER40949, the Department of Energy has supported the educational and research work of the University of Maryland Dynamical Systems and Accelerator Theory (DSAT) Group. The primary focus of this educational/research group has been on the computation and analysis of charged-particle beam transport using Lie algebraic methods, and on advanced methods for the computation of electromagnetic fields and multiparticle phenomena. This Final Report summarizes the accomplishments of the DSAT Group from its inception in 1980 through its end in 2011.

  12. Development of a magnetic beam guiding system for tumor-specific radiotherapy using heavy, charged particles

    International Nuclear Information System (INIS)

    An active, magnetic beam guiding system was developed and tested for the purpose of enhanced and tumor-specific irradiation of irregularly shaped target volumina. Combining intensity-controlled wobbling in rapidly changing magnetic fields with the heavy-ion synchrotron's capacity of fast energy variation achieved a new technique allowing good range modulation. This technique allows the calculated dose distribution to be exactly matched to target contours, and at the same time guarantees best possible quality of the radiation beam, since there is no need for use of mechanical beam shaping members. The components of the scanning system and a specifically designed instrumentation and control concept for this configuration were integrated into the synchrotron's control system, so that there is now a system available offering free selection of beam characteristics combined with energy variation along with the pulsed operation of the accelerator. The system was tested at the biophysical measuring unit of the GSI implementing an elaborated irradiation method at this unit equipped with tools for physico-technical irradiation planning and performance. Methods were designed and tested for optimizing the beam path within a given contour, the optimization taking into account the effects of transmission functions of the scanner components on the results of radiation treatments. (orig.)

  13. High-rate axial-field ionization chamber for particle identification of radioactive beams

    CERN Document Server

    Vadas, J; Visser, G; Alexander, A; Hudan, S; Huston, J; Wiggins, B B; Chbihi, A; Famiano, M; Bischak, M M; deSouza, R T

    2016-01-01

    The design, construction and performance characteristics of a simple axial-field ionization chamber suitable for identifying ions in a radioactive beam are presented. Optimized for use with low-energy radioactive beams (< 5 MeV/A) the detector presents only three 0.5 $\\mu$m/cm$^2$ foils to the beam in addition to the detector gas. A fast charge sensitive amplifier (CSA) integrated into the detector design is also described. Coupling this fast CSA to the axial field ionization chamber produces an output pulse with a risetime of 60-70 ns and a fall time of 100 ns, making the detector capable of sustaining a relatively high rate. Tests with an $\\alpha$ source establish the detector energy resolution as $\\sim$8 $\\%$ for an energy deposit of $\\sim$3.5 MeV. The energy resolution with beams of 2.5 and 4.0 MeV/A $^{39}$K ions and the dependence of the energy resolution on beam intensity is measured. At an instantaneous rate of 3 x 10$^5$ ions/s the energy resolution has degraded to 14% with a pileup of 12%. The go...

  14. Secondary radiation measurements for particle therapy applications: prompt photons produced by $^{4}$He, $^{12}$C and $^{16}$O ion beams in a PMMA target

    CERN Document Server

    Mattei, Ilaria; De Lucia, Erika; Faccini, Riccardo; Frallicciardi, Paola Maria; Mancini-Terracciano, Carlo; Marafini, Michela; Muraro, Silvia; Paramatti, Riccardo; Patera, Vincenzo; Piersanti, Luca; Pinci, Davide; Rucinski, Antoni; Russomando, Andrea; Sarti, Alessio; Sciubba, Adalberto; Camillocci, Elena Solfaroli; Toppi, Marco; Traini, Giacomo; Voena, Cecilia; Battistoni, Giuseppe

    2016-01-01

    Charged particle beams are used in Particle Therapy (PT) to treat oncological patients due to their selective dose deposition in tissues and to their high biological effect in killing cancer cells with respect to photons and electrons used in conventional radiotherapy. Nowadays, protons and carbon ions are used in PT clinical routine but, recently, the interest on the potential application of helium and oxygen beams is growing due to their reduced multiple scattering inside the body and increased linear energy transfer, relative biological effectiveness and oxygen enhancement ratio. The precision of PT demands for online dose monitoring techniques, crucial to improve the quality assurance of treatments. The beam range confined in the irradiated target can be monitored thanks to the neutral or charged secondary radiation emitted by the interactions of hadron beams with matter. Prompt photons are produced by nuclear de-excitation processes and, at present, different dose monitoring and beam range verification t...

  15. Beam-size effect and particle losses at Super$B$ factory developed in Italy

    CERN Document Server

    Kotkin, G L

    2009-01-01

    In the colliders, the macroscopically large impact parameters give a substantial contribution to the standard cross section of the $e^+ e^- \\to e^+ e^- \\gamma$ process. These impact parameters may be much larger than the transverse sizes of the colliding bunches. It means that the standard cross section of this process has to be substantially modified. In the present paper such a beam-size effect is calculated for bremsstrahlung at Super$B$ factory developed in Italy. We find out that this effect reduces beam losses due to bremsstrahlung by about 40%.

  16. Beam-size effect and particle losses at B-factories KEKB and PEP-II

    Energy Technology Data Exchange (ETDEWEB)

    Kotkin, G.L.; Serbo, V.G. E-mail: serbo@math.nsc.ru

    2005-01-01

    In the colliders, the macroscopically large impact parameters give a substantial contribution to the standard cross section of the e{sup +}e{sup -}{yields}e{sup +}e{sup -}{gamma} process. These impact parameters may be much larger than the transverse sizes of the colliding bunches. It means that the standard cross section of this process has to be substantially modified. In the present paper such a beam-size effect is calculated for bremsstrahlung at B-factories KEKB and PEP-II. We find out that this effect reduces beam losses due to bremsstrahlung by about 20%.

  17. Old and new results in regularity theory for diagonal elliptic systems via blowup techniques

    Science.gov (United States)

    Beck, Lisa; Bulíček, Miroslav; Frehse, Jens

    2015-12-01

    We consider quasilinear diagonal elliptic systems in bounded domains subject to Dirichlet, Neumann or mixed boundary conditions. The leading elliptic operator is assumed to have only measurable coefficients, and the nonlinearities (Hamiltonians) are allowed to be of quadratic (critical) growth in the gradient variable of the unknown. These systems appear in many applications, in particular in differential geometry and stochastic differential game theory. We impose on the Hamiltonians structural conditions developed between 1972-2002 and also a new condition (sum coerciveness) introduced in recent years (in the context of the pay off functional in stochastic game theory). We establish existence, Hölder continuity, Liouville properties, W 2, q estimates, etc. for solutions, via a unified approach through the blow-up method. The main novelty of the paper is the introduction of a completely new technique, which in particular leads to smoothness of the solution also for dimensions d ≥ 3.

  18. Existence and Blowup Results for Asymptotically Euclidean Initial Data Sets Generated by the Conformal Method

    CERN Document Server

    Dilts, James

    2016-01-01

    For each set of (freely chosen) seed data, the conformal method reduces the Einstein constraint equations to a system of elliptic equations, the conformal constraint equations. We prove an admissibility criterion, based on a (conformal) prescribed scalar curvature problem, which provides a necessary condition on the seed data for the conformal constraint equations to (possibly) admit a solution. We then consider sets of asymptotically Euclidean (AE) seed data for which solutions of the conformal constraint equations exist, and examine the blowup properties of these solutions as the seed data sets approach sets for which no solutions exist. We also prove that there are AE seed data sets which include a Yamabe nonpositive metric and lead to solutions of the conformal constraints. These data sets allow the mean curvature function to have zeroes.

  19. Evolution PDEs with nonstandard growth conditions existence, uniqueness, localization, blow-up

    CERN Document Server

    Antontsev, Stanislav

    2015-01-01

    This monograph offers the reader a treatment of the theory of evolution PDEs with nonstandard growth conditions. This class includes parabolic and hyperbolic equations with variable or anisotropic nonlinear structure. We develop methods for the study of such equations and present a detailed account of recent results. An overview of other approaches to the study of PDEs of this kind is provided. The presentation is focused on the issues of existence and uniqueness of solutions in appropriate function spaces, and on the study of the specific qualitative properties of solutions, such as localization in space and time, extinction in a finite time and blow-up, or nonexistence of global in time solutions. Special attention is paid to the study of the properties intrinsic to solutions of equations with nonstandard growth.

  20. Focused particle beam nano-machining: the next evolution step towards simulation aided process prediction.

    Science.gov (United States)

    Plank, Harald

    2015-02-01

    During the last decade, focused ion beam processing has been developed from traditionally used Ga(+) liquid ion sources towards higher resolution gas field ion sources (He(+) and Ne(+)). Process simulations not only improve the fundamental understanding of the relevant ion-matter interactions, but also enable a certain predictive power to accelerate advances. The historic 'gold' standard in ion-solid simulations is the SRIM/TRIM Monte Carlo package released by Ziegler, Ziegler and Biersack 2010 Nucl. Instrum. Methods B 268 1818-23. While SRIM/TRIM is very useful for a myriad of applications, it is not applicable for the understanding of the nanoscale evolution associated with ion beam nano-machining as the substrate does not evolve with the sputtering process. As a solution for this problem, a new, adapted simulation code is briefly overviewed and finally addresses these contributions. By that, experimentally observed Ne(+) beam sputter profiles can be explained from a fundamental point of view. Due to their very good agreement, these simulations contain the potential for computer aided optimization towards predictable sputter processes for different nanotechnology applications. With these benefits in mind, the discussed simulation approach represents an enormous step towards a computer based master tool for adaptable ion beam applications in the context of industrial applications.

  1. Focused particle beam nano-machining: the next evolution step towards simulation aided process prediction

    International Nuclear Information System (INIS)

    During the last decade, focused ion beam processing has been developed from traditionally used Ga+ liquid ion sources towards higher resolution gas field ion sources (He+ and Ne+). Process simulations not only improve the fundamental understanding of the relevant ion–matter interactions, but also enable a certain predictive power to accelerate advances. The historic ‘gold’ standard in ion–solid simulations is the SRIM/TRIM Monte Carlo package released by Ziegler, Ziegler and Biersack 2010 Nucl. Instrum. Methods B 268 1818–23. While SRIM/TRIM is very useful for a myriad of applications, it is not applicable for the understanding of the nanoscale evolution associated with ion beam nano-machining as the substrate does not evolve with the sputtering process. As a solution for this problem, a new, adapted simulation code is briefly overviewed and finally addresses these contributions. By that, experimentally observed Ne+ beam sputter profiles can be explained from a fundamental point of view. Due to their very good agreement, these simulations contain the potential for computer aided optimization towards predictable sputter processes for different nanotechnology applications. With these benefits in mind, the discussed simulation approach represents an enormous step towards a computer based master tool for adaptable ion beam applications in the context of industrial applications. (viewpoint)

  2. Effect of ion beam irradiation on metal particle doped polymer composites

    Indian Academy of Sciences (India)

    N L Singh; Sejal Shah; Anjum Qureshi; A Tripathi; F Singh; D K Avasthi; P M Raole

    2011-02-01

    Polymethyl methacrylate (PMMA) was prepared by solution polymerization method. Different concentrations (10, 20 and 40%) of Ni powder were dispersed in PMMA and the composite films were prepared by casting method. These films were irradiated with 120 MeV Ni$^{10+}$ ions at a fluence of 5 × 1012 ions/cm2. Electrical, structural and chemical properties of the composites were studied by means of an LCR meter, X-ray diffraction, FTIR spectroscopy and SEM/AFM, respectively. The results showed that the conductivity increases with metal concentration and also with ion beam irradiation. This reveals that ion beam irradiation promotes the metal/polymer bonding and converts polymeric structure into hydrogen depleted carbon network. It was observed from XRD analysis that percentage crystallinity and crystalline size decrease upon irradiation. This might be attributed to rupture of some polymeric bonds, which is also corroborated with FTIR spectroscopic analysis. Ion beam tempts graphitization of polymeric material by emission of hydrogen and/or other volatile gases. Surface morphology of the pristine and irradiated films was studied by atomic force microscopy (AFM)/scanning electron microscopy (SEM). Result showed that the surface roughness increases after ion beam irradiation.

  3. Beam-Energy and Centrality Dependence of Directed Flow of Identified Particles

    CERN Document Server

    ,

    2015-01-01

    These proceedings present directed flow ($v_1$) measurements in Au+Au collisions from STAR's Beam Energy Scan (BES) program at the Relativistic Heavy-Ion Collider, for $p$, $\\bar{p}$, $\\Lambda$, $\\bar\\Lambda$, $K^\\pm$, $K^0_S$ and $\\pi^\\pm$. At intermediate centrality, protons show a minimum in directed flow slope, $dv_1/dy\\,|_{y\\leq0.8}$, as a function of beam energy. Proton $dv_1/dy$ changes sign near 10 GeV, and the directed flow for $\\Lambda$ is consistent with the proton result. The directed flow slope for net protons shows a clear minimum at 14.5 GeV and becomes positive at beam energies below 10 GeV and above 30 GeV. New results for net-kaon directed flow slope resemble net protons from high energy down to 14.5 GeV, but remain negative at lower energies. The slope $dv_1/dy$ shows a strong centrality dependence, especially for $p$ and $\\Lambda$ at the lower beam energies. Available model calculations are in poor agreement.

  4. Future directions in particle and nuclear physics at multi-GeV hadron beam facilities

    Energy Technology Data Exchange (ETDEWEB)

    Geesaman, D.F. [Argonne National Lab., IL (United States)] [ed.

    1993-11-01

    This report contains papers on the following topics in particle and nuclear physics: hadron dynamics; lepton physics; spin physics; hadron and nuclear spectroscopy; hadronic weak interactions; and Eta physics. These papers have been indexed separately elsewhere.

  5. Future directions in particle and nuclear physics at multi-GeV hadron beam facilities

    International Nuclear Information System (INIS)

    This report contains papers on the following topics in particle and nuclear physics: hadron dynamics; lepton physics; spin physics; hadron and nuclear spectroscopy; hadronic weak interactions; and Eta physics. These papers have been indexed separately elsewhere

  6. Characterization and Antimicrobial Property of Poly(Acrylic Acid) Nanogel Containing Silver Particle Prepared by Electron Beam

    Science.gov (United States)

    Choi, Jong-Bae; Park, Jong-Seok; Khil, Myung-Seob; Gwon, Hui-Jeong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Nho, Young-Chang

    2013-01-01

    In this study, we developed a one step process to synthesize nanogel containing silver nanoparticles involving electron beam irradiation. Water-soluble silver nitrate powder is dissolved in the distilled water and then poly(acrylic acid) (PAAc) and hexane are put into this silver nitrate solution. These samples are irradiated by an electron beam to make the PAAc nanogels containing silver nanoparticles (Ag/PAAc nanogels). The nanoparticles were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In addition, the particle size and zeta-potential were confirmed by a particle size analyzer (PSA). The antibacterial properties of the nanogels were evaluated by paper diffusion test. The Ag/PAAc nanogels had an antibacterial effect against Escherichia coli and Staphylococcus aureus. The nanogels also demonstrated a good healing effect against diabetic ulcer. The size of the Ag/PAAc nanogels decreased with increasing irradiation doses, and the absolute value of the zeta potential increased with increasing irradiation doses. Also, the Ag/PAAc nanogels exhibited good antibacterial activity against both Gram-negative and Gram-positive bacteria. In in vivo wound healing, the Ag/PAAc nanogels have a good healing effect. PMID:23708101

  7. Free vibration control of smart composite beams using particle swarm optimized self-tuning fuzzy logic controller

    Science.gov (United States)

    Zorić, Nemanja D.; Simonović, Aleksandar M.; Mitrović, Zoran S.; Stupar, Slobodan N.; Obradović, Aleksandar M.; Lukić, Nebojša S.

    2014-10-01

    This paper deals with active free vibrations control of smart composite beams using particle-swarm optimized self-tuning fuzzy logic controller. In order to improve the performance and robustness of the fuzzy logic controller, this paper proposes integration of self-tuning method, where scaling factors of the input variables in the fuzzy logic controller are adjusted via peak observer, with optimization of membership functions using the particle swarm optimization algorithm. The Mamdani and zero-order Takagi-Sugeno-Kang fuzzy inference methods are employed. In order to overcome stability problem, at the same time keeping advantages of the proposed self-tuning fuzzy logic controller, this controller is combined with the LQR making composite controller. Several numerical studies are provided for the cantilever composite beam for both single mode and multimodal cases. In the multimodal case, a large-scale system is decomposed into smaller subsystems in a parallel structure. In order to represent the efficiency of the proposed controller, obtained results are compared with the corresponding results in the cases of the optimized fuzzy logic controllers with constant scaling factors and linear quadratic regulator.

  8. The WebCam vs. the Particle Beam: A CRaTER Visualization of the Effects of Radiation

    Science.gov (United States)

    Case, A. W.; Gross, N. A.; Spence, H. E.

    2008-12-01

    The term "radiation" can cause significant anxiety to a general audience in part because of the associated health risks, but also because of lack of a conceptual framework about the nature of radiation. A visual depiction of radiation may go a long way towards providing just such a framework. The CRaTER Team had an opportunity to create just such a video. The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) is a radiation instrument that will fly on the Lunar Reconnaissance Orbiter (LRO) and is designed to determine the effects of energetic particles on living tissue. In order to calibrate CRaTER and characterize its reaction to various radiation environments, the CRaTER team has used particle beam facilities include the Proton Radiation Therapy Facility at Massachusetts General Hospital (MGH). During one of the sessions at MGH, the team placed an off the shelf web camera into the beam and recorded the visual effects. This video recording was used as the basis for an edited video describing what was done and the results. The hope is that this video will provide a general audience with a visual framework for the nature and effects of radiation

  9. A high-speed beam of lithium droplets for collecting diverted energy and particles in ITER [International Thermonuclear Experimental Reactor

    International Nuclear Information System (INIS)

    A high-speed (160m/s) beam (0.14 x 0.86m) of liquid-lithium droplets passing through the divertor region(s) below (and above) the main plasma has the potential to replace and out-perform ''conventional'' solid divertor plates in both heat and particle removal. In addition to superior heat-collection properties, the lithium beam would: remove impurities; require low power to circulate the lithium; exhibit low-recycle divertor operation compatible with lower-hybrid current drive, H-mode plasma confinement, and no flow reversal in the edge plasma; be insensitive to plasma shifts; and finally protect solid structures from the plasma thermal energy for those disruptions that deposit energy preferentially into the divertor while simultaneously being rapidly re-established after a major disruption. Scoping calculations identifying the beam configuration and the droplet dynamics, including formation, MHD effects, gravitational effects, thermal response and hydrodynamics, are presented. Limitations and uncertainties are also discussed. 20 refs., 6 figs., 3 tabs

  10. Studies of the beam finding and targeting accuracy of the CAS-LIBB single-particle microbeam

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Hua; Wu Li-Jun; Wang Shao-Hu; Yu Zeng-Liang; Wang Xu-Fei; Hu Zhi-Wen; Cheng Lian-Yun; Zhang Jun; Zhan Fu-Ru; Li Jun; Chen Bin; Xu Ming-Liang

    2005-01-01

    A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS). The system was designed to deliver a defined number of hydrogen ions produced by a Van de Graaff accelerator, in an energy range of 2.0-3.0MeV, into an area smaller than the nuclei of individual living cells grown on thin plastic films. The beam is collimated by a borosilicate glass capillary that forms the beam-line exit. An computer integrated control program is developed to recognize the cells and to target them one by one for irradiation.Experiments for finding (capturing and recognizing) the microbeam position in the microscope imaging system and measuring the overall targeting accuracy of the facility are presented in this article. When a borosilicate glass capillary with 5μm inner diameter and 980μm length is used as the microbeam collimator, the overall targeting accuracy is that 91% aimed pit clusters are located within 2.4μm radius, and 98% are within 3.6μm radius.

  11. Nonlinear Simulation of Beam Elements Subjected to High Mass Low Velocity Impact Loading using the Smoothed Particle Hydrodynamics (SPH Method

    Directory of Open Access Journals (Sweden)

    Shahrul Niza Mokhatar

    2013-12-01

    Full Text Available In this paper, a fully Lagrangian method namely as Smoothed Particle Hydrodynamics (SPH has been utilized in order to simulate the response of reinforced concrete beam subjected to low velocity impact loading. Models based on this method are proposed to capture an important failure mechanism on compression and tension of the beam elements under dynamic (impact loading condition. Pressure dependant criterion known as Drucker-Prager (DP with a new Plane-Cap (PC yield surface were employed to concrete, and (Von-Mises criterion was applied for steel reinforcement. The constitutive equation of PC model is employed on compression, while, orthotropic constitutive equation due to the damage effect is considered on tension. Meanwhile, Dynamic Increase Factor (DIF was defined separately for the effect of strain rate (SR on the concrete and steel reinforcement. Shear cracking, bending cracking and compressive behavior of the beam were evaluated by using displacement-time histories and overall failure mode. Then, the applicability and efficiency of the proposed models were validated with experimental tests through numerical simulations with different velocity (height of drop-mass.

  12. Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring

    Science.gov (United States)

    Torres-Espallardo, I.; Diblen, F.; Rohling, H.; Solevi, P.; Gillam, J.; Watts, D.; España, S.; Vandenberghe, S.; Fiedler, F.; Rafecas, M.

    2015-05-01

    Particle therapy is a highly conformal radiotherapy technique which reduces the dose deposited to the surrounding normal tissues. In order to fully exploit its advantages, treatment monitoring is necessary to minimize uncertainties related to the dose delivery. Up to now, the only clinically feasible technique for the monitoring of therapeutic irradiation with particle beams is Positron Emission Tomography (PET). In this work we have compared a Resistive Plate Chamber (RPC)-based PET scanner with a scintillation-crystal-based PET scanner for this application. In general, the main advantages of the RPC-PET system are its excellent timing resolution, low cost, and the possibility of building large area systems. We simulated a partial-ring scanner based on an RPC prototype under construction within the Fondazione per Adroterapia Oncologica (TERA). For comparison with the crystal-based PET scanner we have chosen the geometry of a commercially available PET scanner, the Philips Gemini TF. The coincidence time resolution used in the simulations takes into account the current achievable values as well as expected improvements of both technologies. Several scenarios (including patient data) have been simulated to evaluate the performance of different scanners. Initial results have shown that the low sensitivity of the RPC hampers its application to hadron-beam monitoring, which has an intrinsically low positron yield compared to diagnostic PET. In addition, for in-beam PET there is a further data loss due to the partial ring configuration. In order to improve the performance of the RPC-based scanner, an improved version of the RPC detector (modifying the thickness of the gas and glass layers), providing a larger sensitivity, has been simulated and compared with an axially extended version of the crystal-based device. The improved version of the RPC shows better performance than the prototype, but the extended version of the crystal-based PET outperforms all other options.

  13. In-beam evaluation of a medium-size Resistive-Plate WELL gaseous particle detector

    CERN Document Server

    Moleri, L; Arazi, L; Azevedo, C D R; Breskin, A; Coimbra, A E C; Oliveri, E; Pereira, F A; Renous, D Shaked; Schaarschmidt, J; dos Santos, J M F; Veloso, J F C A; Bressler, S

    2016-01-01

    In-beam evaluation of a fully-equipped medium-size 30$\\times$30 cm$^2$ Resistive Plate WELL (RPWELL) detector is presented. It consists here of a single element gas-avalanche multiplier with Semitron ESD225 resistive plate, 1 cm$^2$ readout pads and APV25/SRS electronics. Similarly to previous results with small detector prototypes, stable operation at high detection efficiency (>98%) and low average pad multiplicity (~1.2) were recorded with 150 GeV muon and high-rate pion beams, in Ne/(5%CH$_4$), Ar/(5%CH$_4$) and Ar/(7%CO$_2$). This is an important step towards the realization of robust detectors suitable for applications requiring large-area coverage; among them Digital Hadron Calorimetry.

  14. Effect Of The LEBT Solenoid Magnetic Field On The Beam Generation For Particle Tracking

    CERN Document Server

    Yarmohammadi Satri, M; CERN. Geneva. ATS Department

    2013-01-01

    Linac4 is a 160 MeV H- linear accelerator which will replace the 50 MeV proton Linac2 for upgrade of the LHC injectors with higher intensity and eventually an increase of the LHC luminosity. Linac4 structure is a source, a 45 keV low energy beam transport line (LEBT) with two solenoids, a 3 MeV Radiofrequency Quadrupole (RFQ), a Medium Energy Beam Transport line (MEBT), a 50 Mev DTL, a 100 Mev CCDTL and PIMS up to 160 Mev. We use Travel v4.07 and PathManager code for simulation. Firstly, we need to a file as a source and defining the beginning point (last point in tracking back) of simulation. We recognise the starting point base on the solenoid magnetic property of LEBT.

  15. Beam-size effect and particle losses at SuperB factory developed in Italy

    Energy Technology Data Exchange (ETDEWEB)

    Kotkin, G L; Serbo, V G [Novosibirsk State University, 630090, Novosibirsk, Pirogova st., 2 (Russian Federation)], E-mail: serbo@math.nsc.ru

    2009-06-15

    In the colliders, the macroscopically large impact parameters give a substantial contribution to the standard cross section of the e{sup +}e{sup -}{yields} e{sup +}e{sup -}{gamma} process. These impact parameters may be much larger than the transverse sizes of the colliding bunches. It means that the standard cross section of this process has to be substantially modified. In the present paper such a beam-size effect is calculated for bremsstrahlung at SuperB factory developed in Italy. We find out that this effect reduces beam losses due to bremsstrahlung by about 40%. We perform a critical comparison of our result with that presented in the Conceptual Design Report of the Italian SuperB factory.

  16. Silicon telescope for prototype sensor characterisation using particle beam and cosmic rays

    CERN Multimedia

    Fu, Jinlin

    2016-01-01

    We present the design and the performance of a silicon strip telescope that we have built and recently used as reference tracking system for prototype sensor characterisation. The telescope was operated on beam at the CERN SPS and also using cosmic rays in the laboratory. We will describe the data acquisition system, based on a custom electronic board that we have developed, and the online monitoring system to control the quality of the data in real time.

  17. Thin chamber for profile measuring intensive beams of high-energy charged particles

    International Nuclear Information System (INIS)

    A two-coordinate profile meter developed on the basis of the multichnnel chamber of secondary emission (MCSE) for operation in intense (1010-3x1012 cm-2s-1) 70 GeV proton beams is described. MCSE electrodes are produced by spraying metal at thickness equal to several hundreds angstrem on 10-micron polyamide film. Resource tests have revealed high workability of MCSE when passing 6.5x1017 protons through it

  18. Ionization chambers for monitoring in high-intensity charged particle beams

    CERN Document Server

    McDonald, J; Viren, B; Diwan, M; Erwin, A R; Naples, D; Ping, H

    2003-01-01

    Radiation-hard ionization chambers were tested using an intense electron beam from the accelerator test facility at the Brookhaven National Laboratory. The detectors were designed to be used as the basic element for monitoring muons in the Main Injector Neutrino beamline at the Fermi National Accelerator Laboratory. Measurements of linearity of response, voltage dependence, and the onset of ionization saturation as a function of gap voltage were performed.

  19. High Power Molten Targets for Radioactive Ion Beam Production: from Particle Physics to Medical Applications

    CERN Document Server

    De Melo Mendonca, T M

    2014-01-01

    Megawatt-class molten targets, combining high material densities and good heat transfer properties are being considered for neutron spallation sources, neutrino physics facilities and radioactive ion beam production. For this last category of facilities, in order to cope with the limitation of long diffusion times affecting the extraction of short-lived isotopes, a lead-bismuth eutectic (LBE) target loop equipped with a diffusion chamber has been proposed and tested offline during the EURISOL design study. To validate the concept, a molten LBE loop is now in the design phase and will be prototyped and tested on-line at CERN-ISOLDE. This concept was further extended to an alternative route to produce 1013 18Ne/s for the Beta Beams, where a molten salt loop would be irradiated with 7 mA, 160 MeV proton beam. Some elements of the concept have been tested by using a molten fluoride salt static unit at CERNISOLDE. The investigation of the release and production of neon isotopes allowed the measurement of the diffu...

  20. Two particle tracking and detection in a single Gaussian beam optical trap.

    Science.gov (United States)

    Praveen, P; Yogesha; Iyengar, Shruthi S; Bhattacharya, Sarbari; Ananthamurthy, Sharath

    2016-01-20

    We have studied in detail the situation wherein two microbeads are trapped axially in a single-beam Gaussian intensity profile optical trap. We find that the corner frequency extracted from a power spectral density analysis of intensity fluctuations recorded on a quadrant photodetector (QPD) is dependent on the detection scheme. Using forward- and backscattering detection schemes with single and two laser wavelengths along with computer simulations, we conclude that fluctuations detected in backscattering bear true position information of the bead encountered first in the beam propagation direction. Forward scattering, on the other hand, carries position information of both beads with substantial contribution from the bead encountered first along the beam propagation direction. Mie scattering analysis further reveals that the interference term from the scattering of the two beads contributes significantly to the signal, precluding the ability to resolve the positions of the individual beads in forward scattering. In QPD-based detection schemes, detection through backscattering, thereby, is imperative to track the true displacements of axially trapped microbeads for possible studies on light-mediated interbead interactions. PMID:26835934

  1. Two particle tracking and detection in a single Gaussian beam optical trap.

    Science.gov (United States)

    Praveen, P; Yogesha; Iyengar, Shruthi S; Bhattacharya, Sarbari; Ananthamurthy, Sharath

    2016-01-20

    We have studied in detail the situation wherein two microbeads are trapped axially in a single-beam Gaussian intensity profile optical trap. We find that the corner frequency extracted from a power spectral density analysis of intensity fluctuations recorded on a quadrant photodetector (QPD) is dependent on the detection scheme. Using forward- and backscattering detection schemes with single and two laser wavelengths along with computer simulations, we conclude that fluctuations detected in backscattering bear true position information of the bead encountered first in the beam propagation direction. Forward scattering, on the other hand, carries position information of both beads with substantial contribution from the bead encountered first along the beam propagation direction. Mie scattering analysis further reveals that the interference term from the scattering of the two beads contributes significantly to the signal, precluding the ability to resolve the positions of the individual beads in forward scattering. In QPD-based detection schemes, detection through backscattering, thereby, is imperative to track the true displacements of axially trapped microbeads for possible studies on light-mediated interbead interactions.

  2. Plasmon-enhanced enzyme-linked immunosorbent assay on large arrays of individual particles made by electron beam lithography.

    Science.gov (United States)

    Chen, Si; Svedendahl, Mikael; Antosiewicz, Tomasz J; Käll, Mikael

    2013-10-22

    Ultrasensitive biosensing is one of the main driving forces behind the dynamic research field of plasmonics. We have previously demonstrated that the sensitivity of single nanoparticle plasmon spectroscopy can be greatly enhanced by enzymatic amplification of the refractive index footprint of individual protein molecules, so-called plasmon-enhanced enzyme-linked immunosorbent assay (ELISA). The technique, which is based on generation of an optically dense precipitate catalyzed by horseradish peroxidase at the metal surface, allowed for colorimetric analysis of ultralow molecular surface coverages with a limit of detection approaching the single molecule limit. However, the plasmonic response induced by a single enzyme can be expected to vary for a number of reasons, including inhomogeneous broadening of the sensing properties of individual particles, variation in electric field enhancement over the surface of a single particle and variation in size and morphology of the enzymatic precipitate. In this report, we discuss how such inhomogeneities affect the possibility to quantify the number of molecules bound to a single nanoparticle. The discussion is based on simulations and measurements of large arrays of well-separated gold nanoparticles fabricated by electron beam lithography (EBL). The new data confirms the intrinsic single-molecule sensitivity of the technique but we were not able to clearly resolve the exact number of adsorbed molecules per single particle. The results indicate that the main sources of uncertainty come from variations in sensitivity across the surface of individual particles and between different particles. There is also a considerable uncertainty in the actual precipitate morphology produced by individual enzyme molecules. Possible routes toward further improvements of the methodology are discussed.

  3. THE BLOW-UP PROPERTIES FOR A DEGENERATE SEMILINEAR PARABOLIC EQUATION WITH NONLOCAL SOURCE%带非局部源的退化半线性抛物方程的解的爆破性质

    Institute of Scientific and Technical Information of China (English)

    陈友朋; 刘其林; 谢春红

    2002-01-01

    This paper deals with the blow-up properties of the positive solutions to the nonlocal degenerate semilinear parabolic equation ut-(xαux)x=∫a0f(u)dx in (0,a)×(0,T) under homogeneous Dirichlet conditions. The local existence and uniqueness of classical solution are established. Under appropriate hypotheses, the global existence and blow-up in finite time of positive solutions are obtained. It is also proved that the blow-up set is almost the whole domain. This differs from the local case. Furthermore, the blow-up rate is precisely determined for the special case: f(u)=up,p>1.

  4. Electro-Optical Radiation of a Charged Particle in a Single Laser Beam Field

    CERN Document Server

    Anokhin, M V; Kalegaev, V V; Nagorsky, G A; Panasiuk, M I; Chabanov, V M

    2016-01-01

    A peculiar radiation arising as a result of radiation interference of nonlinear oscillators excited by a monochromatic plane wave field of the incident particle is described. The radiation properties are determined by the fact that a phase of each oscillator radiation fields is synchronized by a wave field, while the radiation itself occurs due to the particle field influence on the oscillators. The consideration is performed for a thin film with negligible density effect. It is supposed that the contribution is given only by a long-wave part of the Weizsacker spectrum for which nonlinear polarization coefficients of medium are large.

  5. Ion micro-beam analysis of single aerosol particles originating from Saharan dust episodes observed in Debrecen, Hungary

    International Nuclear Information System (INIS)

    Complete text of publication follows. Mineral dust arising from deserts is one of the main contributions of the particulate matter in the atmosphere. Due to their wide range of environmental impact and their effect on the radiative forcing of the Earth's climate, study of sources and transport of desert dust is a hot field of atmospheric aerosol research. Approximately 50 episodes of Saharan dust intrusion have been observed in the atmosphere of Debrecen since 1991. In order to separate dust particles of Saharan origin from local sources, and to follow the formation, ageing and evolution of particles originating from long range transport processes, individual aerosol particle analysis was carried out on the Debrecen nuclear microprobe. The samples were collected at a rural site (Hortobagy-Nagyivan) 50 km from Debrecen, on 9th, 12th and 16th November 1996 when a Saharan sand plume reached Eastern Hungary and on 29th November 1997 when no Saharan effect occurred (control sample). Combined off-axis STIM and PIXE-PIXE ion beam analytical techniques were used to determine the quantitative elemental composition of over 250 individual aerosol particles for elements with Z > 6. The influence of Saharan dust was shown through characteristic elemental ratios like Ti/Fe, Ti/Ca and Al/Ca (Table 1) These tracer ratios were found to be higher in case of Hortobagy-Nagyivan than in the case of urban environments which were highly influenced by local emissions, especially re-suspended soil dust due to urban traffic. Hierarchical cluster analysis was performed on the obtained database to classify the particles. The overall composition was dominated by mineral dust. The conclusion have been drawn that the mineralogical composition of Saharan dust and the local soil was very similar, so Al, Si, Ca cannot be used as tracers of Saharan dust. However, particle classes characteristic to the Saharan samples were found. One of them is characterised by high Fe and Ti content, while the other

  6. Global existence and blow-up of solutions to a parabolic system with nonlocal sources and boundaries

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with a semi-linear parabolic system with nonlinear nonlocal sources and nonlocal boundaries.By using super-and sub-solution techniques,we first give the sufficient conditions that the classical solution exists globally and blows up in a finite time respectively,and then give the necessary and sufficient conditions that two components u and v blow up simultaneously.Finally,the uniform blow-up profiles in the interior are presented.

  7. Global existence and blow-up of solutions to a parabolic system with nonlocal sources and boundaries

    Institute of Scientific and Technical Information of China (English)

    Ling-hua KONG; Ming-xin WANG

    2007-01-01

    This paper deals with a semi-linear parabolic system with nonlinear nonlocal sources and nonlocal boundaries. By using super- and sub-solution techniques, we first give the sufficient conditions that the classical solution exists globally and blows up in a finite time respectively, and then give the necessary and sufficient conditions that two components u and v blow up simultaneously. Finally, the uniform blow-up profiles in the interior are presented.

  8. USE OF INCIDENT AND REFLECTED SOLAR PARTICLE BEAMS TO TRACE THE TOPOLOGY OF MAGNETIC CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Lun C. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Malandraki, Olga E.; Dorrian, Gareth [Institute of Astronomy and Astrophysics, National Observatory of Athens (Greece); Reames, Donald V. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Ng, Chee K. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Wang Linghua, E-mail: ltan@umd.edu [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)

    2012-05-10

    Occasionally, large solar energetic particle (SEP) events occur inside magnetic clouds (MCs). In this work, the onset time analysis, the peak intensity analysis, and the decay phase analysis of SEPs are used to investigate two large SEP events inside MCs: the 1998 May 2 and 2002 April 21 events. The onset time analysis of non-relativistic electrons and {approx}MeV nucleon{sup -1} heavy ions shows the stability of the magnetic loop structure during a period of a few hours in the events examined. The joint analysis of pitch-angle distributions and peak intensities of electrons exhibits that, depending on the particle pitch angle observed at 1 AU, in the April event the reflection point of particles may be distributed along a wide spatial range, implying that the magnetic loop is a magnetic bottle connected to the Sun with both legs. In contrast, in the May event particle reflection occurs abruptly at the magnetic mirror formed by a compressed field enhancement behind the interplanetary shock, consistent with its open field line topology.

  9. Commercial CMOS image sensors as X-ray imagers and particle beam monitors

    International Nuclear Information System (INIS)

    CMOS image sensors are widely used in several applications such as mobile handsets webcams and digital cameras among others. Furthermore they are available across a wide range of resolutions with excellent spectral and chromatic responses. In order to fulfill the need of cheap systems as beam monitors and high resolution image sensors for scientific applications we exploited the possibility of using commercial CMOS image sensors as X-rays and proton detectors. Two different sensors have been mounted and tested. An Aptina MT9v034, featuring 752 × 480 pixels, 6μm × 6μm pixel size has been mounted and successfully tested as bi-dimensional beam profile monitor, able to take pictures of the incoming proton bunches at the DeFEL beamline (1–6 MeV pulsed proton beam) of the LaBeC of INFN in Florence. The naked sensor is able to successfully detect the interactions of the single protons. The sensor point-spread-function (PSF) has been qualified with 1MeV protons and is equal to one pixel (6 mm) r.m.s. in both directions. A second sensor MT9M032, featuring 1472 × 1096 pixels, 2.2 × 2.2 μm pixel size has been mounted on a dedicated board as high-resolution imager to be used in X-ray imaging experiments with table-top generators. In order to ease and simplify the data transfer and the image acquisition the system is controlled by a dedicated micro-processor board (DM3730 1GHz SoC ARM Cortex-A8) on which a modified LINUX kernel has been implemented. The paper presents the architecture of the sensor systems and the results of the experimental measurements

  10. Intense, pulsed, charged particle beams and associated applications to materials science

    Energy Technology Data Exchange (ETDEWEB)

    Yatsui, K.; Grigoriu, C.; Masugata, K.; Jiang, W.; Sonegawa, T.; Nakagawa, Y.; Eka Prijono, A.C. [Nagaoka Univ. of Technology, Niigata (Japan)

    1997-03-01

    We have demonstrated successful preparation of thin films and nanosize powders by using the technique of intense pulsed ion beam evaporation. In this paper, we review the experimental results of thin film deposition of ZnS, YBa{sub 2}Cu{sub 3}O{sub 7-x}, BaTiO{sub 3}, cBN, ZrO{sub 2}, ITO, and apatite, as well as the experimental results of the synthesis of nanosize powders of Al{sub 2}O{sub 3}. (author)

  11. Performance of magnetically-injected-plasma opening switches on the particle beam fusion accelerator 2

    International Nuclear Information System (INIS)

    Plasma opening switch (POS) experiments have been performed on the PBFA II ion beam accelerator to develop a switch which will provide voltage and power gain to an applied-B lithium ion diode. These experiments have successfully coupled power to electron and ion beam diodes using a Magnetically-Injected-Plasma (MIP) POS. Carbon plasma with electron densities of 1 x 1012 to 2 x 1013 /cm3 have been injected from the anode into the 8 cm gap of the 20-ohm Magnetically-Insulated-Transmission Line (MITL) of PBFA II along a Br,z magnetic field. The MIP switch uses the inertia of the plasma to keep the switch closed and the magnetic pressure of Bθ from the conduction current to open the switch. The configuration of the injecting magnetic field and the plasma source has a significant effect on the efficiency of coupling power to high impedance loads. Plasma near the center of the injecting magnetic field limits the opening impedance of the switch and subsequently the power delivered to the load. The axial location of the switch with respect to the load has also been identified as a critical parameter in increasing the coupling efficiency. A length of 10 to 20 cm of MITL between the POS and the load has increased the power delivered to the load. Data on switch performance with high impedance loads and factors which improved performance are discussed

  12. Characterization techniques for the high-brightness particle beams of the Advanced Photon Source (APS)

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.

    1993-08-01

    The Advanced Photon Source (APS) will be a third-generation synchrotron radiation (SR) user facility in the hard x-ray regime (10--100 keV). The design objectives for the 7-GeV storage ring include a positron beam natural emittance of 8 {times} 10{sup {minus}9} m-rad at an average current of 100 mA. Proposed methods for measuring the transverse and longitudinal profiles will be described. Additionally, a research and development effort using an rf gun as a low-emittance source of electrons for injection into the 200- to 650-MeV linac subsystem is underway. This latter system is projected to produce electron beams with a normalized, rms emittance of {approximately}2 {pi} mm-mrad at peak currents of near one hundred amps. This interesting characterization problem will also be briefly discussed. The combination of both source types within one laboratory facility will stimulate the development of diagnostic techniques in these parameter spaces.

  13. Possibility of particle-beam-pumped Ar-Xe laser as an inertial confinement fusion driver

    International Nuclear Information System (INIS)

    Fission-product-beam pumped Ar-Xe laser as a candidate of the driver for a hybrid fission-fusion reactor is studied. Such hybrid reactor can reduce the power requirements for the laser driver. These Ar-Xe lasers have been realized as reactor pumped lasers (RPL) with pulsed reactors. However, high power RPL experiments often face the problem of premature termination of laser output power with respect to the pumping power. Several reasons, including temperature effects, outgassing of impurities from walls have been discussed. Two experiments, elucidating the influence of water vapor impurities in the lasing gas mixture and laser threshold, and the effects of temperature rise in the laser gas on laser output have been performed at the Munich Tandem accelerator, using 100 MeV 32S9+ beams, thus simulating RPL experiments at a pumping power density of ∼ 100 W/cm3. Using these experimental and theoretical results, these RPL-oscillations can be stabilized with high instinctive efficiency. Laser-gas-purification systems and breakeven conditions and related requirements on the hybrid reactor using RPL driver schematically discussed. (author)

  14. Matching the phase volume of a transported charged particle beam by a doublet of quadrupole lenses

    International Nuclear Information System (INIS)

    The problem of matching the phase volume of a transported beam is commonly solved by nonlinear programming methods. Writing a system of matching equations that is transcendental, one can turn to the following stage: its solution by direct numerical methods. In this paper the system of matching equations will be reduced to one equation with one unknown by means of successive analytical transformations. This was achieved by the corresponding substitution of the variables. The last equation was solved on a computer. As a result, such characteristics as drift lengths, lengths and gradients of magnetic lenses are written analytically depending on the chosen vector of the parameters and the unknown quantity as indicated. The formulas obtained are realized as a FORTRAN program on a CDC-6500 computer. In the user's dialogue with the computer, this program allows to correct fast all values of free parameters and to choose the most economical version of the calculated matching structure. Geometrical and magnetic characteristics of the beam transport system under investigation are presented in the version conclusively chosen. (orig.)

  15. Self-modulation of a long externally injected relativistic charged-particle beam in a laser wake field acceleration scheme. A preliminary quantum-like investigation

    International Nuclear Information System (INIS)

    Recent investigations indicate that sufficiently long beams of charged particles, travelling in a plasma, experience the phenomenon of self-modulation. The self-modulation is driven by the plasma wake field excitation due to the beam itself, and it may become unstable under certain conditions. A preliminary theoretical investigation of the self-modulation of a relativistic charged-particle beam in overdense plasma in the presence of a preformed plasma wave is carried out, within the quantum-like description of charged particle beams provided by the Thermal Wave Model. A simple physical model for the self-modulation is put forward, described by a nonlinear Schrödinger equation coupled with the Poisson-like equation for the plasma wake potential (so-called Fedele–Shukla equations). The physical mechanism is based on the interplay of three concomitant effects, the radial thermal dispersion (associated with the emittance ε), the radial ponderomotive effects of a preexisting plasma wave (which provides the guidance for the beam), and the self-interaction of the plasma wake field generated by the beam itself

  16. Severe signal loss in diamond beam loss monitors in high particle rate environments by charge trapping in radiation-induced defects

    CERN Document Server

    Kassel, Florian; Dabrowski, Anne; de Boer, Wim

    2016-01-01

    The beam condition monitoring leakage (BCML) system is a beam monitoring device in the compact muon solenoid (CMS) experiment at the large hadron collider (LHC). As detectors 32 poly-crystalline (pCVD) diamond sensors are positioned in rings around the beam pipe. Here, high particle rates occur from the colliding beams scattering particles outside the beam pipe. These particles cause defects, which act as traps for the ionization, thus reducing the charge collection efficiency (CCE). However, the loss in CCE was much more severe than expected from low rate laboratory measurements and simulations, especially in single-crystalline (sCVD) diamonds, which have a low initial concentration of defects. The reason why in real experiments the CCE is much worse than in laboratory experiments is related to the ionization rate. At high particle rates the trapping rate of the ionization is so high compared with the detrapping rate, that space charge builds up. This space charge reduces locally the internal electric field,...

  17. Meteoric smoke particle properties derived using dual-beam Arecibo UHF observations of D-region spectra during different seasons

    Science.gov (United States)

    Fentzke, J. T.; Janches, D.; Strelnikova, I.; Rapp, M.

    2009-12-01

    We present a seasonal study of the presence and characteristics of meteoric smoke particles (MSPs) in the D-region plasma derived from observations using the Gregorian and line feeds of the 430 MHz dual-beam Arecibo Observatory (AO) incoherent scatter radar (ISR) in Puerto Rico (18oN,67oW). MSPs are the product of re-condensation of ablated meteoric material and are believed to be the condensation nuclei for the formation of ice particles in the polar mesopause region. These CNs can then be responsible for the formation of polar mesospheric clouds (PMCs), noctilucent clouds (NLCs) and polar mesospheric summer echoes (PMSEs). For this work, we simultaneously employed both AO antenna feeds to define two radar beams inclined 15o east and west of zenith (Janches et al., 2006). Because of the non-vertical pointing, the sampled spectra are Doppler shifted due to the rapidly changing neutral dynamics of the MLT region. We correct this effect by removing the Doppler shift using the radial velocities estimated every ~2 min and then integrate the corrected spectra for longer periods to enhance signal-to-noise ratio (SNR) and better investigate the variability of MSP properties. We determine MSP radii and number densities utilizing a method similar to the one developed by Strelnikova et al. (2007) in which the autocorrelation function (ACF) is approximated as the sum of two exponential decays, i.e., the power spectrum is approximated as the sum of two Lorentzians. This method, which assumes mono-disperse particles, allows us to determine mean particle properties in the 80-95 km altitude range during the hours of 10-14 AO LT when the detected SNR from the D-region is highest. Results from this work show MSP radii approximately 0.6-1.5 nm is size depending on altitude and season. Also, MSP densities as a function of altitude and season are determined with the aid of the IRI model resulting in values on the order of 102-104 per cubic centimeter. Our error analysis shows that

  18. Circular motion of particles suspended in a Gaussian beam with circular polarization validates the spin part of the internal energy flow

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya.; Maksimyak, P. P.;

    2012-01-01

    switching to the right (left) circular polarization, the particles performed spinning motion in agreement with the angular momentum imparted by the field, but they were involved in an orbital rotation around the beam axis as well, which in previous works [Y. Zhao et al, Phys. Rev. Lett. 99, 073901 (2007......)] was treated as evidence for the spin-to orbital angular momentum conversion. Since in our realization the moderate focusing of the beam excluded the possibility for such a conversion, we consider the observed particle behavior as a demonstration of the macroscopic “spin energy flow” predicted by the theory...

  19. X-ray and pressure conditions on the first wall of a particle beam inertial confinement reactor

    International Nuclear Information System (INIS)

    Because of the presence of a chamber gas in a particle beam reactor cavity, nonneutron target debris created from thermonuclear burn will be modified or stopped before it reaches the first reactor wall. The resulting modified spectra and pulse lengths of the debris need to be calculated to determine first wall effects. Further, the cavity overpressure created by the momentum and energy exchange between the debris and gas must also be calculated to determine its effect. The purpose of this paper is to present results of the debris-background gas problem obtained with a one fluid, two temperature plasma hydrodynamic computer code model which includes multifrequency radiation transport. Spherical symmetry, ideal gas equation of state, and LTE for each radiation frequency group were assumed. The transport of debris ions was not included and all the debris energy was assumed to be in radiation. The calculated x-ray spectra and pulse lengths and the background overpressure are presented

  20. Coherent instabilities of intense high-energy "white" charged-particle beams in the presence of nonlocal effects within the context of the Madelung fluid description

    CERN Document Server

    Fedele, R; Lisak, M

    2005-01-01

    A hydrodynamical description of coherent instabilities that take place in the longitudinal dynamics of a charged-particle coasting beam in a high-energy accelerating machine is presented. This is done in the framework of the Madelung fluid picture provided by the Thermal Wave Model. The well known coherent instability charts in the complex plane of the longitudinal coupling impedance for monochromatic beams are recovered. The results are also interpreted in terms of the deterministic approach to modulational instability analysis usually given for monochromatic large amplitude wave train propagation governed by the nonlinear Schr\\"odinger equation. The instability analysis is then extended to a non-monochromatic coasting beam with a given thermal equilibrium distribution, thought as a statistical ensemble of monochromatic incoherent coasting beams ("white" beam). In this hydrodynamical framework, the phenomenon of Landau damping is predicted without using any kinetic equation governing the phase space evolutio...

  1. Influence of the beam-size or MD-effect on particle losses at B-factories PEP-II and KEKB

    CERN Document Server

    Kotkin, G L

    2004-01-01

    For the $e^+ e^- \\to e^+ e^- \\gamma$ process at colliding beams, macroscopically large impact parameters give an essential contribution to the standard cross section. These impact parameters may be much larger than the transverse sizes of the colliding bunches. It means that the standard calculations have to be essentially modify. In the present paper such a beam-size or MD-effect is calculated for bremsstrahlung at B-factories PEP-II and KEKB using the list of nominal parameters from Review of Particle Physics (2002). We find out that this effect reduces beam losses due to bremsstrahlung by about 20%.

  2. TURTLE with MAD input (Trace Unlimited Rays Through Lumped Elements) -- A computer program for simulating charged particle beam transport systems and DECAY TURTLE including decay calculations

    International Nuclear Information System (INIS)

    TURTLE is a computer program useful for determining many characteristics of a particle beam once an initial design has been achieved, Charged particle beams are usually designed by adjusting various beam line parameters to obtain desired values of certain elements of a transfer or beam matrix. Such beam line parameters may describe certain magnetic fields and their gradients, lengths and shapes of magnets, spacings between magnetic elements, or the initial beam accepted into the system. For such purposes one typically employs a matrix multiplication and fitting program such as TRANSPORT. TURTLE is designed to be used after TRANSPORT. For convenience of the user, the input formats of the two programs have been made compatible. The use of TURTLE should be restricted to beams with small phase space. The lumped element approximation, described below, precludes the inclusion of the effect of conventional local geometric aberrations (due to large phase space) or fourth and higher order. A reading of the discussion below will indicate clearly the exact uses and limitations of the approach taken in TURTLE

  3. Simulations, optimizations, and microdosimetric measurements of beam quality for heavy-ion tumor therapy. A charged (particle) issue

    International Nuclear Information System (INIS)

    distributions in lineal energy when comparing two methods of particle beam application to determine a potential impact on the biological effect.

  4. Absorbed dose assessment in particle-beam irradiated metal-oxide and metal-nonmetal memristors

    Directory of Open Access Journals (Sweden)

    Knežević Ivan D.

    2012-01-01

    Full Text Available Absorbed dose was estimated after Monte Carlo simulation of proton and ion beam irradiation on metal-oxide and metal-nonmetal memristors. A memristive device comprises two electrodes, each of a nanoscale width, and a double-layer active region disposed between and in electrical contact with electrodes. Following materials were considered for the active region: titanium dioxide, zirconium dioxide, hafnium dioxide, strontium titanium trioxide and galium nitride. Obtained results show that significant amount of oxygen ion - oxygen and nonmetal ion - nonmetal vacancy pairs is to be generated. The loss of such vacancies from the device is believed to deteriorate the device performance over time. Estimated absorbed dose values in the memristor for different constituting materials are of the same order of magnitude because of the close values of treshold displacement energies for the investigated materials.

  5. Experimental and theoretical JINR studies on the development of stochastic cooling of charged particle beams

    Science.gov (United States)

    Sidorin, A. O.; Trubnikov, G. V.; Shurkhno, N. A.

    2016-03-01

    In 2010, based on the superconducting heavy-ion synchrotron Nuclotron, a new accelerating complex NICA (Nuclotron-based Ion Collider fAcility) started to be constructed at the Laboratory of High Energy Physics of the Joint Institute for Nuclear Research, its key facility being the 1.0 - 4.5 GeV per nucleon heavy ion collider. For the purpose of effectively collecting statistics, an average collider luminosity of 1027 cm -2 s -1 is required. With this collider energy, the cooling of the beam both in the process of storage and during the experiment is mandatory to ensure the required parameters. In this paper, a possible new regime of stochastic cooling is examined.

  6. Fusion reactions initiated by laser-accelerated particle beams in a laser-produced plasma

    CERN Document Server

    Labaune, C; Depierreux, S; Goyon, C; Loisel, G; Yahia, V; Rafelski, J

    2013-01-01

    The advent of high-intensity pulsed laser technology enables the generation of extreme states of matter under conditions that are far from thermal equilibrium. This in turn could enable different approaches to generating energy from nuclear fusion. Relaxing the equilibrium requirement could widen the range of isotopes used in fusion fuels permitting cleaner and less hazardous reactions that do not produce high energy neutrons. Here we propose and implement a means to drive fusion reactions between protons and boron-11 nuclei, by colliding a laser-accelerated proton beam with a laser-generated boron plasma. We report proton-boron reaction rates that are orders of magnitude higher than those reported previously. Beyond fusion, our approach demonstrates a new means for exploring low-energy nuclear reactions such as those that occur in astrophysical plasmas and related environments.

  7. A comparison of weak-turbulence and particle-in-cell simulations of weak electron-beam plasma interaction

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliffe, H., E-mail: h.ratcliffe@warwick.ac.uk; Brady, C. S.; Che Rozenan, M. B. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Nakariakov, V. M. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); School of Space Research, Kyung Hee University, 446-701 Yongin, Gyeonggi (Korea, Republic of); Central Astronomical Observatory of the Russian Academy of Sciences, 196140 St. Petersburg (Russian Federation)

    2014-12-15

    Quasilinear theory has long been used to treat the problem of a weak electron beam interacting with plasma and generating Langmuir waves. Its extension to weak-turbulence theory treats resonant interactions of these Langmuir waves with other plasma wave modes, in particular, ion-sound waves. These are strongly damped in plasma of equal ion and electron temperatures, as sometimes seen in, for example, the solar corona and wind. Weak turbulence theory is derived in the weak damping limit, with a term describing ion-sound wave damping then added. In this paper, we use the EPOCH particle-in-cell code to numerically test weak turbulence theory for a range of electron-ion temperature ratios. We find that in the cold ion limit, the results agree well, but for increasing ion temperature the three-wave resonance becomes broadened in proportion to the ion-sound wave damping rate. Additionally, we establish lower limits on the number of simulation particles needed to accurately reproduce the electron and wave distributions in their saturated states and to reproduce their intermediate states and time evolution. These results should be taken into consideration in, for example, simulations of plasma wave generation in the solar corona of Type III solar radio bursts from the corona to the solar wind and in weak turbulence investigations of ion-acoustic lines in the ionosphere.

  8. A heavy particle beam analyser with a mosaic of junction detectors

    International Nuclear Information System (INIS)

    The problem is to make appear on a cathode oscilloscope screen a matrix of luminous points whose brilliance will depend upon the number of nuclear particles between 0.01 to 1000 particles per second striking a pianomosaic of semi-conductor diodes. The initial matrix studied consists of 100 elements (10 rows of 10 columns each) scanned 100 times per second, which gives a commutation time of 100 μs. The equipment comprises three parts: the semiconductor detectors with their amplifiers, the commutation matrix, the CR tube and its scanning system. 1. Each semiconductor diode is followed by a transistorized pulse-amplifier which brings the signal to a level compatible with easy commutation (100 mV to 1 V). These pulses are stored in a low-capacity integration capacitor. 2. A high-impedance commutation matrix is used (in view of the weakness of the charges involved); it has eight diodes per commutation point and practically discharges the capacitor for each sweep. 3. The Wehnelt cylinder of the CRT is connected to an amplifier at the commutator output. Scanning is stepped in X and Y. The fluorescent screen is of type R and its afterglow effect provides the required time constant, which is approximately a second. (author)

  9. Effects of Alpha Particle and Proton Beam Irradiation as Putative Cross-Talk between A549 Cancer Cells and the Endothelial Cells in a Co-Culture System

    Directory of Open Access Journals (Sweden)

    Hélène Riquier

    2015-03-01

    Full Text Available Background: High-LET ion irradiation is being more and more often used to control tumors in patients. Given that tumors are now considered as complex organs composed of multiple cell types that can influence radiosensitivity, we investigated the effects of proton and alpha particle irradiation on the possible radioprotective cross-talk between cancer and endothelial cells. Materials and Methods: We designed new irradiation chambers that allow co-culture study of cells irradiated with a particle beam. A549 lung carcinoma cells and endothelial cells (EC were exposed to 1.5 Gy of proton beam or 1 and 2 Gy of alpha particles. Cell responses were studied by clonogenic assays and cell cycle was analyzed by flow cytometry. Gene expression studies were performed using Taqman low density array and by RT-qPCR. Results: A549 cells and EC displayed similar survival fraction and they had similar cell cycle distribution when irradiated alone or in co-culture. Both types of irradiation induced the overexpression of genes involved in cell growth, inflammation and angiogenesis. Conclusions: We set up new irradiation chamber in which two cell types were irradiated together with a particle beam. We could not show that tumor cells and endothelial cells were able to protect each other from particle irradiation. Gene expression changes were observed after particle irradiation that could suggest a possible radioprotective inter-cellular communication between the two cell types but further investigations are needed to confirm these results.

  10. Effects of Alpha Particle and Proton Beam Irradiation as Putative Cross-Talk between A549 Cancer Cells and the Endothelial Cells in a Co-Culture System

    Energy Technology Data Exchange (ETDEWEB)

    Riquier, Hélène; Abel, Denis [URBC-NARILIS, University of Namur, 61 rue de Bruxelles, Namur 5000 (Belgium); Wera, Anne-Catherine; Heuskin, Anne-Catherine [LARN-PMR, NARILIS, University of Namur, Namur 5000 (Belgium); Genard, Géraldine [URBC-NARILIS, University of Namur, 61 rue de Bruxelles, Namur 5000 (Belgium); Lucas, Stéphane [LARN-PMR, NARILIS, University of Namur, Namur 5000 (Belgium); Michiels, Carine, E-mail: carine.michiels@unamur.be [URBC-NARILIS, University of Namur, 61 rue de Bruxelles, Namur 5000 (Belgium)

    2015-03-18

    Background: High-LET ion irradiation is being more and more often used to control tumors in patients. Given that tumors are now considered as complex organs composed of multiple cell types that can influence radiosensitivity, we investigated the effects of proton and alpha particle irradiation on the possible radioprotective cross-talk between cancer and endothelial cells. Materials and Methods: We designed new irradiation chambers that allow co-culture study of cells irradiated with a particle beam. A549 lung carcinoma cells and endothelial cells (EC) were exposed to 1.5 Gy of proton beam or 1 and 2 Gy of alpha particles. Cell responses were studied by clonogenic assays and cell cycle was analyzed by flow cytometry. Gene expression studies were performed using Taqman low density array and by RT-qPCR. Results: A549 cells and EC displayed similar survival fraction and they had similar cell cycle distribution when irradiated alone or in co-culture. Both types of irradiation induced the overexpression of genes involved in cell growth, inflammation and angiogenesis. Conclusions: We set up new irradiation chamber in which two cell types were irradiated together with a particle beam. We could not show that tumor cells and endothelial cells were able to protect each other from particle irradiation. Gene expression changes were observed after particle irradiation that could suggest a possible radioprotective inter-cellular communication between the two cell types but further investigations are needed to confirm these results.

  11. Effects of Alpha Particle and Proton Beam Irradiation as Putative Cross-Talk between A549 Cancer Cells and the Endothelial Cells in a Co-Culture System

    International Nuclear Information System (INIS)

    Background: High-LET ion irradiation is being more and more often used to control tumors in patients. Given that tumors are now considered as complex organs composed of multiple cell types that can influence radiosensitivity, we investigated the effects of proton and alpha particle irradiation on the possible radioprotective cross-talk between cancer and endothelial cells. Materials and Methods: We designed new irradiation chambers that allow co-culture study of cells irradiated with a particle beam. A549 lung carcinoma cells and endothelial cells (EC) were exposed to 1.5 Gy of proton beam or 1 and 2 Gy of alpha particles. Cell responses were studied by clonogenic assays and cell cycle was analyzed by flow cytometry. Gene expression studies were performed using Taqman low density array and by RT-qPCR. Results: A549 cells and EC displayed similar survival fraction and they had similar cell cycle distribution when irradiated alone or in co-culture. Both types of irradiation induced the overexpression of genes involved in cell growth, inflammation and angiogenesis. Conclusions: We set up new irradiation chamber in which two cell types were irradiated together with a particle beam. We could not show that tumor cells and endothelial cells were able to protect each other from particle irradiation. Gene expression changes were observed after particle irradiation that could suggest a possible radioprotective inter-cellular communication between the two cell types but further investigations are needed to confirm these results

  12. A Computational Investigation of the Finite-Time Blow-Up of the 3D Incompressible Euler Equations Based on the Voigt Regularization

    CERN Document Server

    Larios, Adam; Titi, Edriss S; Wingate, Beth

    2015-01-01

    We report the results of a computational investigation of two recently proved blow-up criteria for the 3D incompressible Euler equations. These criteria are based on an inviscid regularization of the Euler equations known as the 3D Euler-Voigt equations. The latter are known to be globally well-posed. Moreover, simulations of the 3D Euler-Voigt equations also require less resolution than simulations of the 3D Euler equations for fixed values of the regularization parameter $\\alpha>0$. Therefore, the new blow-up criteria allow one to gain information about possible singularity formation in the 3D Euler equations indirectly; namely, by simulating the better-behaved 3D Euler-Voigt equations. The new criteria are only known to be sufficient criteria for blow-up. Therefore, to test the robustness of the inviscid-regularization approach, we also investigate analogous criteria for blow-up of the 1D Burgers equation, where blow-up is well-known to occur.

  13. The CMS Barrel Calorimeter Response to Particle Beams from 2 to 350 GeV/c

    CERN Document Server

    Abdullin, Salavat; Acharya, Bannaje Sripathi; Adam, Nadia; Adams, Mark Raymond; Adzic, Petar; Akchurin, Nural; Akgun, Ugur; Albayrak, Elif Asli; Alemany-Fernandez, Reyes; Almeida, Nuno; Anagnostou, Georgios; Andelin, Daniel; Anderson, E Walter; Anfreville, Marc; Anicin, Ivan; Antchev, Georgy; Antunovic, Zeljko; Arcidiacono, Roberta; Arenton, Michael Wayne; Auffray, Etiennette; Argiro, Stefano; Askew, Andrew; Atramentov, Oleksiy; Ayan, S; Arcidy, M; Aydin, Sezgin; Aziz, Tariq; Baarmand, Marc M; Babich, Kanstantsin; Baccaro, Stefania; Baden, Drew; Baffioni, Stephanie; Bakirci, Mustafa Numan; Balazs, Michael; Banerjee, Sunanda; Banerjee, Sudeshna; Bard, Robert; Barge, Derek; Barnes, Virgil E; Barney, David; Barone, Luciano; Bartoloni, Alessandro; Baty, Clement; Bawa, Harinder Singh; Baiatian, G; Bandurin, Dmitry; Beauceron, Stephanie; Bell, Ken W; Bencze, Gyorgy; Benetta, Robert; Bercher, Michel; Beri, Suman Bala; Bernet, Colin; Berntzon, Lisa; Berthon, Ursula; Besançon, Marc; Betev, Botjo; Beuselinck, Raymond; Bhatnagar, Vipin; Bhatti, Anwar; Biino, Cristina; Blaha, Jan; Bloch, Philippe; Blyth, Simon; Bodek, Arie; Bornheim, Adolf; Bose, Suvadeep; Bose, Tulika; Bourotte, Jean; Brett, Angela Mary; Brown, Robert M; Britton, David; Budd, Howard; Bühler, M; Burchesky, Kyle; Busson, Philippe; Camanzi, Barbara; Camporesi, Tiziano; Cankocak, Kerem; Carrell, Kenneth Wayne; Carrera, E; Cartiglia, Nicolo; Cavallari, Francesca; Cerci, Salim; Cerutti, cM; Chang, Paoti; Chang, You-Hao; Charlot, Claude; Chen, E Augustine; Chen, Wan-Ting; Chen, Zheng-Yu; Chendvankar, Sanjay; Chipaux, Rémi; Choudhary, Brajesh C; Choudhury, Rajani Kant; Chung, Yeon Sei; Clarida, Warren; Cockerill, David J A; Combaret, Christophe; Conetti, Sergio; Cossutti, Fabio; Cox, Bradley; Cremaldi, Lucien Marcus; Cushman, Priscilla; Cussans, David; Dafinei, Ioan; Damgov, Jordan; Da Silva Di Calafiori, Diogo Raphael; Daskalakis, Georgios; Davatz, Giovanna; David, A; De Barbaro, Pawel; Debbins, Paul; Deiters, Konrad; Dejardin, Marc; Djordjevic, Milos; Deliomeroglu, Mehmet; Della Negra, Rodolphe; Della Ricca, Giuseppe; Del Re, Daniele; Demianov, A; De Min, Alberto; Denegri, Daniel; Depasse, Pierre; de Visser, Theo; Descamps, Julien; Deshpande, Pandurang Vishnu; Díaz, Jonathan; Diemoz, Marcella; Di Marco, Emanuele; Dimitrov, Lubomir; Dissertori, Günther; Dittmar, Michael; Djambazov, Lubomir; Dobrzynski, Ludwik; Drndarevic, Snezana; Duboscq, Jean Etienne; Dugad, Shashikant; Dumanoglu, Isa; Duru, Firdevs; Dutta, Dipanwita; Dzelalija, Mile; Efthymiopoulos, I; Elias, John E; Peisert, A; El-Mamouni, H; Elvira, D; Emeliantchik, Igor; Eno, Sarah Catherine; Ershov, Alexander; Erturk, Sefa; Esen, Selda; Eskut, Eda; Evangelou, Ioannis; Evans, David; Fabbro, Bernard; Faure, Jean-Louis; Fay, Jean; Fenyvesi, Andras; Ferri, Federico; Fisher, Wade Cameron; Flower, Paul S; Franci, Daniele; Franzoni, Giovanni; Freeman, Jim; Freudenreich, Klaus; Funk, Wolfgang; Ganjour, Serguei; Gargiulo, Corrado; Gascon, Susan; Gataullin, Marat; Gaultney, Vanessa; Gamsizkan, Halil; Gavrilov, Vladimir; Geerebaert, Yannick; Genchev, Vladimir; Gentit, François-Xavier; Gerbaudo, Davide; Gershtein, Yuri; Ghezzi, Alessio; Ghodgaonkar, Manohar; Gilly, Jean; Givernaud, Alain; Gleyzer, Sergei V; Gninenko, Sergei; Go, Apollo; Gobbo, Benigno; Godinovic, Nikola; Golubev, Nikolai; Golutvin, Igor; Goncharov, Petr; Gong, Datao; Govoni, Pietro; Grant, Nicholas; Gras, Philippe; Grassi, Tullio; Green, Dan; Greenhalgh, R J S; Gribushin, Andrey; Grinev, B; Guevara Riveros, Luz; Guillaud, Jean-Paul; Gurtu, Atul; Murat Guler, A; Gülmez, Erhan; Gümüs, K; Haelen, T; Hagopian, Sharon; Hagopian, Vasken; Haguenauer, Maurice; Halyo, Valerie; Hamel de Monchenault, Gautier; Hansen, Sten; Hashemi, Majid; Hauptman, John M; Hazen, Eric; Heath, Helen F; Heering, Arjan Hendrix; Heister, Arno; Heltsley, Brian; Hill, Jack; Hintz, Wieland; Hirosky, Robert; Hobson, Peter R; Honma, Alan; Hou, George Wei-Shu; Hsiung, Yee; Hunt, Adam; Husejko, Michal; Ille, Bernard; Ilyina, N; Imlay, Richard; Ingram, D; Ingram, Quentin; Isiksal, Engin; Jarry, Patrick; Jarvis, Chad; Jeong, Chiyoung; Jessop, Colin; Johnson, Kurtis F; Jones, John; Jovanovic, Dragoslav; Kaadze, Ketino; Kachanov, Vassili; Kaftanova, V; Kailas, Swaminathan; Kalagin, Vladimir; Kalinin, Alexey; Kalmani, Suresh Devendrappa; Karmgard, Daniel John; Kataria, Sushil Kumar; Kaur, Manjit; Kaya, Mithat; Kaya, Ozlem; Kayis-Topaksu, A; Kellogg, Richard G; Kennedy, Bruce W; Khmelnikov, Alexander; Kim, Heejong; Kisselevich, I; Kloukinas, Kostas; Kodolova, Olga; Kohli, Jatinder Mohan; Kokkas, Panagiotis; Kolberg, Ted; Kolossov, V; Korablev, Andrey; Korneev, Yury; Kosarev, Ivan; Kramer, Laird; Krasnikov, Nikolai; Krinitsyn, Alexander; Krokhotin, Andrey; Krpic, Dragomir; Kryshkin, V; Kubota, Yuichi; Kubrik, A; Kuleshov, Sergey; Kumar, Arun; Kumar, P; Kunori, Shuichi; Kuo, Chen-Cheng; Kurt, Pelin; Kyberd, Paul; Kyriakis, Aristotelis; Laasanen, Alvin T; Ladygin, Vladimir; Laird, Edward; Landsberg, Greg; Laszlo, Andras; Lawlor, C; Lazic, Dragoslav; Lebeau, Michel; Lecomte, Pierre; Lecoq, Paul; Ledovskoy, Alexander; Lee, Sang Joon; Leshev, Georgi; Lethuillier, Morgan; Levchuk, Leonid; Lin, Sheng-Wen; Lin, Willis; Linn, Stephan; Lintern, A L; Litvine, Vladimir; Litvintsev, Dmitri; Litov, Leander; Lobolo, L; Locci, Elizabeth; Lodge, Anthony B; Longo, Egidio; Loukas, Demetrios; Los, Serguei; Lubinsky, V; Luckey, Paul David; Lukanin, Vladimir; Lustermann, Werner; Lynch, Clare; Ma, Yousi; Machado, Emanuel; Mahlke-Krüger, H; Maity, Manas; Majumder, Gobinda; Malberti, Martina; Malclès, Julie; Maletic, Dimitrije; Mandjavidze, Irakli; Mans, Jeremy; Manthos, Nikolaos; Maravin, Yurii; Marchica, Carmelo; Marinelli, Nancy; Markou, Athanasios; Markou, Christos; Marlow, Daniel; Markowitz, Pete; Marone, Matteo; Martínez, German; Mathez, Hervé; Matveev, Viktor; Mavrommatis, Charalampos; Maurelli, Georges; Mazumdar, Kajari; Meridiani, Paolo; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mescheryakov, G; Mestvirishvili, Alexi; Mikhailin, V; Milenovic, Predrag; Miller, Michael; Milleret, Gérard; Miné, Philippe; Möller, A; Mohammadi-Najafabadi, M; Mohanty, Ajit Kumar; Moissenz, P; Mondal, Naba Kumar; Moortgat, Filip; Mossolov, Vladimir; Mur, Michel; Musella, Pasquale; Musienko, Yuri; Nagaraj, P; Nardulli, Alessandro; Nash, Jordan; Nédélec, Patrick; Negri, Pietro; Newman, Harvey B; Nikitenko, Alexander; Norbeck, Edwin; Nessi-Tedaldi, Francesca; Obertino, Maria Margherita; Olson, Jonathan; Onel, Yasar; Onengüt, G; Organtini, Giovanni; Orimoto, Toyoko; Ozkan, Cigdem; Ozkurt, Halil; Ozkorucuklu, Suat; Ozok, Ferhat; Paganoni, Marco; Paganini, Pascal; Paktinat, S; Pal, Andras; Palma, Alessandro; Panev, Bozhidar; Pant, Lalit Mohan; Papadakis, Antonakis; Papadakis, Ioannis; Papadopoulos, Ioannis; Paramatti, Riccardo; Parracho, P; Pastrone, Nadia; Patil, Mandakini Ravindra; Patterson, Juliet Ritchie; Pauss, Felicitas; Penzo, Aldo; Petrakou, Eleni; Petrushanko, Sergey; Petrosian, A; Phillips II, David; Pikalov, Vladimir; Piperov, Stefan; Piroué, Pierre; Podrasky, V; Polatoz, A; Pompos, Arnold; Popescu, Sorina; Posch, C; Pozdnyakov, Andrey; Ptochos, Fotios; Puljak, Ivica; Pullia, Antonino; Punz, Thomas; Puzovic, Jovan; Qian, Weiming; Ragazzi, Stefano; Rahatlou, Shahram; Ralich, Robert; Rande, J; Razis, Panos A; Redaelli, Nicola; Reddy, L; Reidy, Jim; Renker, Dieter; Reucroft, Steve; Reymond, Jean-Marc; Ribeiro, Pedro Quinaz; Röser, Ulf; Rogalev, Evgueni; Rogan, Christopher; Roh, Youn; Rohlf, James; Romanteau, Thierry; Rondeaux, Françoise; Ronquest, Michael; Ronzhin, Anatoly; Rosowsky, André; Rovelli, Chiara; Ruchti, Randy; Rumerio, Paolo; Rusack, Roger; Rusakov, Sergey V; Ryan, Matthew John; Ryazanov, Anton; Safronov, Grigory; Sala, Leonardo; Salerno, Roberto; Sanders, David A; Santanastasio, Francesco; Sanzeni, Christopher; Sarycheva, Ludmila; Satyanarayana, B; Schinzel, Dietrich; Schmidt, Ianos; Seez, Christopher; Sekmen, Sezen; Semenov, Sergey; Senchishin, V; Sergeyev, S; Serin, Meltem; Sever, Ramazan; Sharp, Peter; Shepherd-Themistocleous, Claire; Siamitros, Christos; Sillou, Daniel; Singh, Jas Bir; Singovsky, Alexander; Sirois, Yves; Sirunyan, Albert M; Silva, J; Silva, Pedro; Skuja, Andris; Sharma, Seema; Sherwood, Brian; Shiu, Jing-Ge; Shivpuri, Ram Krishen; Shukla, Prashant; Shumeiko, Nikolai; Smirnov, Vitaly; Smith, Brian; Smith, Vincent J; Sogut, Kenan; Sonmez, Nasuf; Sorokin, Pavel; Spezziga, Mario; Sproston, Martin; Stefanovich, R; Stockli, F; Stolin, Viatcheslav; Sudhakar, Katta; Sulak, Lawrence; Suter, Henry; Suzuki, Ichiro; Swain, John; Tabarellide Fatis, T; Talov, Vladimir; Takahashi, Maiko; Tcheremoukhine, Alexandre; Teller, Olivier; Teplov, Konstantin; Theofilatos, Konstantinos; Thiebaux, Christophe; Thomas, Ray; Timciuc, Vladlen; Timlin, Claire; Titov, Maksym; Tobias, A; Tonwar, Suresh C; Topakli, Huseyin; Topkar, Anita; Triantis, Frixos A; Troshin, Sergey; Tully, Christopher; Turchanovich, L; Tyurin, Nikolay; Ueno, Koji; Ulyanov, A; Uzunian, Andrey; Vanini, A; Vankov, Ivan; Vardanyan, Irina; Varela, F; Varela, Joao; Vasil ev, A; Velasco, Mayda; Vergili, Mehmet; Verma, Piyush; Verrecchia, Patrice; Vesztergombi, Gyorgy; Veverka, Jan; Vichoudis, Paschalis; Vidal, Richard; Virdee, Tejinder; Vishnevskiy, Alexander; Vlassov, E; Vodopiyanov, Igor; Volobouev, Igor; Volkov, Alexey; Volodko, Anton; Von Gunten, Hans Peter; Wang, Lei; Wang, Minzu; Wardrope, David; Weber, Markus; Weng, Joanna; Werner, Jeremy Scott; Wetstein, Matthew; Winn, Dave; Wigmans, Richard; Williams, Jennifer C; Whitmore, Juliana; Won, Steven; Wu, Shouxiang; Yang, Yong; Yaselli, Ignacio; Yazgan, Efe; Yetkin, Taylan; Yohay, Rachel; Zabi, Alexandre; Zálán, Peter; Zamiatin, Nikolai; Zarubin, Anatoli; Zelepoukine, Serguei; Zeyrek, Mehmet; Zhang, Jia-Wen; Zhang, Lin; Zhu, Kejun; Zhu, Ren-Yuan

    2008-01-01

    The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. The analysis of the differences in calorimeter response to charged pions, kaons, protons and antiprotons and a detailed discussion of the underlying phenomena are presented. We also show techniques that apply corrections to the signals from the considerably different electromagnetic (EB) and hadronic (HB) barrel calorimeters in reconstructing the energies of hadrons. Above 5 GeV/c, these corrections improve the energy resolution of the combined system where the stochastic term equals 84.7$\\pm$1.6$\\%$ and the constant term is 7.4$\\pm$0.8$\\%$. The corrected mean response remains constant within 1.3$\\%$ rms.

  14. STEREO/SEPT observations of upstream particle events: almost monoenergetic ion beams

    Directory of Open Access Journals (Sweden)

    A. Klassen

    2009-05-01

    Full Text Available We present observations of Almost Monoenergetic Ion (AMI events in the energy range of 100–1200 keV detected with the Solar Electron and Proton Telescope (SEPT onboard both STEREO spacecraft. The energy spectrum of AMI events contain 1, 2, or 3 narrow peaks with the relative width at half maximum of 0.1–0.7 and their energy maxima varies for different events from 120 to 1200 keV. These events were detected close to the bow-shock (STEREO-A&B and to the magnetopause at STEREO-B as well as unexpectedly far upstream of the bow-shock and far away from the magnetotail at distances up to 1100 RE (STEREO-B and 1900 RE (STEREO-A. We discuss the origin of AMI events, the connection to the Earth's bow-shock and to the magnetosphere, and the conditions of the interplanetary medium and magnetosphere under which these AMI bursts occur. Evidence that the detected spectral peaks were caused by quasi-monoenergetic beams of protons, helium, and heavier ions are given. Furthermore, we present the spatial distribution of all AMI events from December 2006 until August 2007.

  15. Subcellular Spatial Correlation of Particle Traversal and Biological Response in Clinical Ion Beams

    Energy Technology Data Exchange (ETDEWEB)

    Niklas, Martin, E-mail: m.niklas@dkfz.de [Division of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Abdollahi, Amir [German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Molecular and Translational Radiation Oncology, Heidelberg Ion-Beam Therapy Center, University of Heidelberg Medical School and National Center for Tumor Diseases, German Cancer Research Center, Heidelberg (Germany); Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center, Heidelberg (Germany); Akselrod, Mark S. [Stillwater Crystal Growth Division, Landauer Inc, Stillwater, Oklahoma (United States); Debus, Jürgen [German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Molecular and Translational Radiation Oncology, Heidelberg Ion-Beam Therapy Center, University of Heidelberg Medical School and National Center for Tumor Diseases, German Cancer Research Center, Heidelberg (Germany); Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center, Heidelberg (Germany); Jäkel, Oliver [Division of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); German Cancer Consortium, National Center for Radiation Research in Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg (Germany); Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center, Heidelberg (Germany); and others

    2013-12-01

    Purpose: To report on the spatial correlation of physical track information (fluorescent nuclear track detectors, FNTDs) and cellular DNA damage response by using a novel hybrid detector (Cell-Fit-HD). Methods and Materials: The FNTDs were coated with a monolayer of human non-small cell lung carcinoma (A549) cells and irradiated with carbon ions (270.55 MeV u{sup −1}, rising flank of the Bragg peak). Phosphorylated histone variant H2AX accumulating at the irradiation-induced double-strand break site was labeled (RIF). The position and direction of ion tracks in the FNTD were registered with the location of the RIF sequence as an ion track surrogate in the cell layer. Results: All RIF sequences could be related to their corresponding ion tracks, with mean deviations of 1.09 μm and −1.72 μm in position and of 2.38° in slope. The mean perpendicular between ion track and RIF sequence was 1.58 μm. The mean spacing of neighboring RIFs exhibited a regular rather than random spacing. Conclusions: Cell-Fit-HD allows for unambiguous spatial correlation studies of cell damage with respect to the intracellular ion traversal under therapeutic beam conditions.

  16. Subcellular Spatial Correlation of Particle Traversal and Biological Response in Clinical Ion Beams

    International Nuclear Information System (INIS)

    Purpose: To report on the spatial correlation of physical track information (fluorescent nuclear track detectors, FNTDs) and cellular DNA damage response by using a novel hybrid detector (Cell-Fit-HD). Methods and Materials: The FNTDs were coated with a monolayer of human non-small cell lung carcinoma (A549) cells and irradiated with carbon ions (270.55 MeV u−1, rising flank of the Bragg peak). Phosphorylated histone variant H2AX accumulating at the irradiation-induced double-strand break site was labeled (RIF). The position and direction of ion tracks in the FNTD were registered with the location of the RIF sequence as an ion track surrogate in the cell layer. Results: All RIF sequences could be related to their corresponding ion tracks, with mean deviations of 1.09 μm and −1.72 μm in position and of 2.38° in slope. The mean perpendicular between ion track and RIF sequence was 1.58 μm. The mean spacing of neighboring RIFs exhibited a regular rather than random spacing. Conclusions: Cell-Fit-HD allows for unambiguous spatial correlation studies of cell damage with respect to the intracellular ion traversal under therapeutic beam conditions

  17. Beams of Particles and Papers. The Role of Preprint Archives in High Energy Physics

    CERN Document Server

    Delfanti, Alessandro

    2016-01-01

    In high energy physics scholarly papers circulate primarily through online preprint archives based on a centralized repository, arXiv.org, that physicists simply refer to as 'the archive.' This is not a tool for preservation and memory, but rather a space of flows where written objects are detected and then disappear, and their authors made available for scrutiny. In this work I analyse the reading and publishing practices of two subsets of particle physicists, theorists and experimentalists. In order to be recognized as legitimate and productive members of their community, physicists need to abide by the temporalities and authorial practices structured by the archive. Theorists live in a state of accelerated time that shapes their reading and publishing practices around a 24 hour cycle. Experimentalists resolve to tactics that allow them to circumvent the slowed-down time and invisibility they experience as members of large collaborations. As digital archives for the exchange of preprint articles emerge in o...

  18. BLOW-UP SOLUTIONS FOR A CLASS OF NONLINEAR PARABOLIC EQUATIONS WITH MIXED BOUNDARY CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    DING Juntang; LI Shengjia

    2005-01-01

    The type of problem under consideration is{ut = (△)(a(u)b(x)(△)u) + g(x,q,t)f(u)in D(0,T),u=0onГ1×(0,T), (e)u/(e)u+ +σ(x,t)u = 0 on Г2×(0,T),Г1∪Г2=(e)D, u(x,0) = uo(x) ≥ 0,(≠) 0 in( ̄D),where D is a smooth bounded domain of RN,q=|(△)u|2.By constructing an auxiliary function and using Hopf's maximum principles on it,existence theorems of blow-up solutions,upper bound of “blow-up time” and upper estimates of “blow-up rate” axe given under suitable assumptions on a,b,f,g,σ and initial date uo(x).The obtained results are applied to some examples in which a,b,f,g and σ are power functions or exponential functions.

  19. Blowup phenomena for the compressible euler and euler-poisson equations with initial functional conditions.

    Science.gov (United States)

    Wong, Sen; Yuen, Manwai

    2014-01-01

    We study, in the radial symmetric case, the finite time life span of the compressible Euler or Euler-Poisson equations in R (N) . For time t ≥ 0, we can define a functional H(t) associated with the solution of the equations and some testing function f. When the pressure function P of the governing equations is of the form P = Kρ (γ) , where ρ is the density function, K is a constant, and γ > 1, we can show that the nontrivial C (1) solutions with nonslip boundary condition will blow up in finite time if H(0) satisfies some initial functional conditions defined by the integrals of f. Examples of the testing functions include r (N-1)ln(r + 1), r (N-1) e (r) , r (N-1)(r (3) - 3r (2) + 3r + ε), r (N-1)sin((π/2)(r/R)), and r (N-1)sinh r. The corresponding blowup result for the 1-dimensional nonradial symmetric case is also given.

  20. X-ray production cross-sections measurements for high-energy alpha particle beams: New dedicated set-up and first results with aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Dupuis, T., E-mail: T.Dupuis@ulg.ac.be [Centre Europeen d' Archeometrie, Atomique et Spectroscopie, Universite de Liege, Sart Tilman B15, B-4000 Liege (Belgium); Institut de Physique Nucleaire, Atomique et Spectroscopie, Universite de Liege, Sart Tilman B15, B-4000 Liege (Belgium); Chene, G., E-mail: Gregoire.Chene@ulg.ac.be [Centre Europeen d' Archeometrie, Atomique et Spectroscopie, Universite de Liege, Sart Tilman B15, B-4000 Liege (Belgium); Institut de Physique Nucleaire, Atomique et Spectroscopie, Universite de Liege, Sart Tilman B15, B-4000 Liege (Belgium); Mathis, F., E-mail: Francois.Mathis@ulg.ac.be [Centre Europeen d' Archeometrie, Atomique et Spectroscopie, Universite de Liege, Sart Tilman B15, B-4000 Liege (Belgium); Institut de Physique Nucleaire, Atomique et Spectroscopie, Universite de Liege, Sart Tilman B15, B-4000 Liege (Belgium); and others

    2011-12-15

    The 'IPNAS' laboratory, in collaboration with the 'Centre Europeen d'Archeometrie' is partly focused on material analysis by means of IBA techniques: PIXE, PIGE and RBS. A new transport beam line has been developed at our CGR-520 MeV cyclotron to analyze Cultural Heritage objects using these techniques. This facility allows us to produce proton and alpha particle beams with energies up to 20 MeV. A vacuum chamber dedicated to X-ray production and Non-Rutherford cross-section measurements has been recently constructed. After determination of the chamber's geometry for X-ray detection using thin foils of several elements (11 Less-Than-Or-Slanted-Equal-To Z Less-Than-Or-Slanted-Equal-To 82) and 3 MeV proton beams, the measurement of the X-ray production cross-sections in the 6-12 MeV energy range has started using alpha particle beams on light element targets. These experiments contribute to the filling a serious lack of experimental values for alpha particles of this particular energy range in databases. The recent decision to focus our work on the alpha particle interaction with light elements was taken because of the high interest of the low Z elements in the field of archaeometry.

  1. Measurement of neutron and charged particle contamination in high energy medical therapy x-ray beams using recoil track registration in polycarbonate foils

    International Nuclear Information System (INIS)

    The production of photoneutrons and high-energy charged particles by betatrons and linear accelerators used in radiotherapy is measured. It is concluded there exists sufficient contamination in high-energy x-ray beams to be a consideration in certain radiotherapy situations

  2. On the possibility of gamma-laser pumping occurring at a charged particle counter motion and in density-modulated electron beams by a high frequency intensive radiation

    International Nuclear Information System (INIS)

    The given report deals with the problem of motion and radiation of relativistic electron in a field of opposite plane density-modulated relativistic electron beam. Physical essence of high-frequency intensive radiation origin could be explained, first by the additional Lorentz reduction of the electron beam modulation period (modulation period Λ in a laboratory co-ordinate system reduces by a factor γ as compared with the modulation period in a beam co-ordinate system) and, secondly, a simultaneous γ-fold increase of transverse components of relativistic electrons of the beam electric and magnetic fields. Such a moving modulated electron beam can be regarded as a dynamic micro-ondulator. Unlike static micro-ondulators we can observe here one more positive moment along with a small period Λ = Λ'/γ, i.e. the electric and magnetic fields in a transverse direction are changed according to the law of exp(-2πx/Λ'). It means that charged particle interaction with a dynamic micro-ondulator will be effective in a wide range of transverse distances, i.e., to get an intensive short wave radiation one can use charged particle beams with rather large apertures which leads to an additional radiation intensity increase. A discussion is given showing that the proposed dynamic modulator possesses some essential merits. A detailed calculation is presented. (author)

  3. Strengthening of Zircaloy-4 using Oxide Particles by Laser Beam Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang-Il; Park, Dong-Jun; Park, Jung-Hwan; Park, Jeong-Yong; Kim, Hyun-Gil; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Oxide particles such as Y{sub 2}O{sub 3} and CeO{sub 2} were dispersed homogeneously in a Zircaloy-4 plate surface using an LBS method. From the tensile test at 380 .deg. C, the strength of laser ODS alloying on the Zircaloy-4 sheet was increased more than 50% when compared to the initial state of the sheet, although the ODS alloyed layer was less than 20% of the specimen thickness. This technology showed a good opportunity to increase the strength without major changes in the substrates of zirconium-based alloys. Accident tolerant fuel (ATF) cladding is being developed globally after the Fukushima accident with the demands for the nuclear fuel having higher safety at normal operation conditions as well as even in a severe accident conditions. Korea Atomic Energy Research Institute (KAERI) is one of the leading organizations for developing ATF claddings. One concept is to form an oxidation-resistant layer on Zr cladding surface. The other is to increase high-temperature mechanical strength of Zr tube. The oxide dispersion strengthened (ODS) zirconium was proposed to increase the strength of the Zr-based alloy up to high temperatures.

  4. Nonexistence of Positive Solutions to a Quasilinear Elliptic System And Blow-up Estimates for a Non-Newtonian Filtration System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ In these years, semilinear reaction-diffusion systems of the Fujita type ut=Δu+vm (A) vt Δ v + un, (x,t) ∈Ω× (0,T), as well as the related elliptic systems with the region Ω Rn RN, m ,n > 1 were studied by a number of authors, The problems concerning (A) include the existence and multiplicity of global solutions, blowing-up, blow-up rates, and blow-up sets, uniqueness and nonuniqueness, etc. For (B) , there are problems such as existence and nonexistence, uniqueness and nonuniqueness, and so on. On the contrary, it seems that little is known about the result for quasilinear reaction-diffusion systems (non-Newtonian filtration systems) and quasilinear elliptic systems, especially about that of blow-up rate estimates for quasilinear reaction-diffusion systems.

  5. PREFACE: Advanced Science Research Symposium 2009 Positron, Muon and other exotic particle beams for materials and atomic/molecular sciences (ASR2009)

    Science.gov (United States)

    Higemoto, Wataru; Kawasuso, Atsuo

    2010-05-01

    It is our great pleasure to deliver the proceedings of ASR2009, the Advanced Science Research International Symposium 2009. ASR2009 is part of a series of symposia which is hosted by the Japan Atomic Energy Agency, Advanced Science Research Center (JAEA-ASRC), and held every year with different scientific topics. ASR2009 was held at Tokai in Japan from 10-12 November 2009. In total, 102 participants, including 29 overseas scientists, made 44 oral presentations and 64 poster presentations. In ASR2009 we have focused on material and atomic/molecular science research using positrons, muons and other exotic particle beams. The symposium covered all the fields of materials science which use such exotic particle beams. Positrons, muons and other beams have similar and different features. For example, although positrons and muons are both leptons having charge and spin, they give quite different information about materials. A muon mainly detects the local magnetic state of the solid, while a positron detects crystal imperfections and electron momenta in solids. Other exotic particle beams also provide useful information about materials which is not able to be obtained with muons or positrons. Therefore, the complementary use of particle beams, coupled with an understanding of their relative advantages, leads to greater excellence in materials research. This symposium crossed the fields of muon science, positron science, unstable-nuclei science, and other exotic particle-beam science. We therefore believe that ASR2009 became an especially important meeting for finding new science with exotic particle beams. Finally, we would like to extend our appreciation to all the participants, committee members, and support staff for their great efforts to make ASR2009 a fruitful symposium. ASR2009 Chairs Wataru Higemoto and Atsuo Kawasuso Advanced Science Research Center, Japan Atomic Energy Agency Organizing committee Y Hatano, JAEA (Director of ASRC) M Fujinami, Chiba Univ. R H

  6. SELF-SIMILAR SOLUTIONS AND BLOW-UP PHENOMENA FOR A TWO-COMPONENT SHALLOW WATER SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Shouming ZHOU; Chunlai MU; Liangchen WANG

    2013-01-01

    In this article,we consider a two-component nonlinear shallow water system,which includes the famous 2-component Camassa-Holm and Degasperis-Procesi equations as special cases.The local well-posedess for this equations is established.Some sufficient conditions for blow-up of the solutions in finite time are given.Moreover,by separation method,the self-similar solutions for the nonlinear shallow water equations are obtained,and which local or global behavior can be determined by the corresponding Emden equation.

  7. Estimates for the resolvent kernel of the Laplacian on p.c.f. self similar fractals and blowups

    CERN Document Server

    Rogers, Luke G

    2010-01-01

    We provide a method for obtaining upper estimates of the resolvent kernel of the Laplacian on a post-critically finite self-similar fractal that relies on a self-similar series decomposition of the resolvent. Decay estimates on the positive real axis are proved by analyzing functions satisfying an interior eigenfunction condition with positive eigenvalue. These lead to estimates on the complement of the negative real axis via the Phragmen-Lindelof theorem. Applications are given to kernels for functions of the Laplacian, including the heat kernel, and to proving the existence of a self-similar series decomposition for the Laplacian resolvent on fractal blowups.

  8. Tight focusing of a radially polarized Laguerre–Bessel–Gaussian beam and its application to manipulation of two types of particles

    International Nuclear Information System (INIS)

    The intensity distributions near the focus for radially polarized Laguerre–Bessel–Gaussian beams by a high numerical aperture objective in the immersion liquid are computed based on the vector diffraction theory. We compare the focusing properties of the radially polarized Laguerre–Bessel–Gaussian beams with those of Laguerre–Gaussian and Bessel–Gaussian modes. Furthermore, the effects of the optimally designed concentric three-zone phase filters on the intensity profiles in the focal region are examined. We further analyze the radiation forces on Rayleigh particles produced by the highly focused radially polarized Laguerre–Bessel–Gaussian beams using the specially engineered three-zone phase filters. - Highlights: • The tightly focusing of radially polarized LBG beams is examined. • The focusing performances of LBG beams are preferable over that of LG and BG modes. • A bright spot and an optical cage can be formed by special phase modulation. • These special focusing patterns can stably manipulate two types of particles

  9. Integration of a model-independent interface for RBE predictions in a treatment planning system for active particle beam scanning

    International Nuclear Information System (INIS)

    Especially for heavier ions such as carbon ions, treatment planning systems (TPSs) for ion radiotherapy depend on models predicting the relative biological effectiveness (RBE) of the particles involved. Such models are subject to intensive research and the choice of the optimal RBE model is a matter of debate. On the other hand TPSs are often strongly coupled to particular RBE models and transition even to extended models of the same family can be difficult. We present here a model-independent interface which allows the unbiased use of any RBE model capable of providing dose–effect curves (even sampled curves) for a TPS. The full decoupling between the RBE model and TPS is based on the beam-mixing model proposed by Lam which is, in contrast to the often-used Zaider–Rossi model, independent of the explicit form of the underlying dose–effect curves. This approach not only supports the refinement of RBE models without adaptations of the TPS—which we demonstrate by means of the local effect model (LEM)—but also allows the comparison of very different model approaches on a common basis. We exemplify this by a comparison between the LEM and a model from the literature for proton RBE prediction. (paper)

  10. Particle induced X-ray emission and ion dose distribution in a biological micro-beam: Geant4 Monte Carlo simulations

    International Nuclear Information System (INIS)

    The goal of a microbeam is to deliver a highly localized and small dose to the biological medium. This can be achieved by using a set of collimators that confine the charged particle beam to a very small spatial area of the order of microns in diameter. By using a system that combines an appropriate beam detection method that signals to a beam shut-down mechanism, a predetermined and counted number of energetic particles can be delivered to targeted biological cells. Since the shutter and the collimators block a significant proportion of the beam, there is a probability of the production of low energy X-rays and secondary electrons through interactions with the beam. There is little information in the biological microbeam literature on potential X-ray production. We therefore used Monte Carlo simulations to investigate the potential production of particle-induced X-rays and secondary electrons in the collimation system (which is predominantly made of tungsten) and the subsequent possible effects on the total absorbed dose delivered to the biological medium. We found, through the simulation, no evidence of the escape of X-rays or secondary electrons from the collimation system for proton energies up to 3 MeV as we found that the thickness of the collimators is sufficient to reabsorb all of the generated low energy X-rays and secondary electrons. However, if the proton energy exceeds 3 MeV our simulations suggest that 10 keV X-rays can escape the collimator and expose the overlying layer of cells and medium. If the proton energy is further increased to 4.5 MeV or beyond, the collimator can become a significant source of 10 keV and 59 keV X-rays. These additional radiation fields could have effects on cells and these results should be verified through experimental measurement. We suggest that researchers using biological microbeams at higher energies need to be aware that cells may be exposed to a mixed LET radiation field and be careful in their interpretation of

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-17

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

  12. Electrostatically focused addressable field emission array chips (AFEA's) for high-speed massively parallel maskless digital E-beam direct write lithography and scanning electron microscopy

    Science.gov (United States)

    Thomas, Clarence E.; Baylor, Larry R.; Voelkl, Edgar; Simpson, Michael L.; Paulus, Michael J.; Lowndes, Douglas H.; Whealton, John H.; Whitson, John C.; Wilgen, John B.

    2002-12-24

    Systems and methods are described for addressable field emission array (AFEA) chips. A method of operating an addressable field-emission array, includes: generating a plurality of electron beams from a pluralitly of emitters that compose the addressable field-emission array; and focusing at least one of the plurality of electron beams with an on-chip electrostatic focusing stack. The systems and methods provide advantages including the avoidance of space-charge blow-up.

  13. Managing the Real-time Behaviour of a Particle Beam Factory The CERN Proton Synchrotron Complex and its Timing System Principles

    CERN Document Server

    Bau, J C; Lewis, J; Philippe, J

    1998-01-01

    In the CERN 26 Gev Proton Synchrotron (PS) accelerator network, super-cycles are defined as sequences of different kinds of beams produced repetitively [Fig.1]. Each of these beams is characterised by attributes such as particle type, beam energy, its route through the accelerator network, and the final end user. The super-cycle is programmed by means of an editor through which the operational requirements of the physics programme can be described. Each beam in the normal sequence may later be replaced by a set of spare beams automatically depending on software and hardware interlocks and requests presented to the Master Timing Generator (MTG [Glos. 1]). The MTG calculates at run time how each beam is to be manufactured, and sends a telegram [Glos. 3] message to each accelerator, just before each cycle, describing what it should be doing now and during the next cycle. These messages, together with key machine timing events and clocks are encoded onto a timing distribution drop net where they are distributed a...

  14. Probing scalar particle and unparticle couplings in e{sup +}e{sup -}{yields}t anti t with transversely polarized beams

    Energy Technology Data Exchange (ETDEWEB)

    Groote, S. [Tartu Uelikool, Loodus- ja Tehnoloogiateaduskond, Fueuesika Instituut, Tartu (Estonia); Institut fuer Physik der Johannes-Gutenberg-Universitaet, Mainz (Germany); Liivat, H.; Ots, I.; Sepp, T. [Tartu Uelikool, Loodus- ja Tehnoloogiateaduskond, Fueuesika Instituut, Tartu (Estonia)

    2010-03-15

    In searching for indications of new-physics scalar particle and unparticle couplings in e{sup +}e{sup -}{yields}t anti t, we consider the role of transversely polarized initial beams at e{sup +}e{sup -} colliders. By using a general relativistic spin density matrix formalism for describing the particles spin states, we find analytical expressions for the differential cross section of the process with t or anti t polarization measured, including the anomalous coupling contributions. Thanks to the transversely polarized initial beams these contributions are first order anomalous coupling corrections to the Standard Model (SM) contributions. We present and analyze the main features of the SM and anomalous coupling contributions. We show how differences between SM and anomalous coupling contributions provide means to search for anomalous coupling manifestations at future e{sup +}e{sup -} linear colliders. (orig.)

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

    CERN Document Server

    Noll, Daniel

    2015-01-01

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

  16. Three-dimensional particle-in-cell modeling of relativistic electron beam production and transport for KrF laser pumping

    International Nuclear Information System (INIS)

    The effects of diode geometry and externally applied magnetic fields on electron beam production and transport for KrF laser pumping has been studied using two and three dimensional particle-in-cell models. The efficiency with which electrons may be transported through the foil support structure depends critically on the size of the openings in the structure as well as the magnitude of the applied magnetic fields. As the electron diodes become larger the current which can be produced becomes limited by the self-magnetic field of the beam. Simulations show the diode current is limited to slightly more than the usual ''critical current.'' However this electron flow is found to be unstable. The application of strong guide fields not only increases the current from the diode but tends to stabilize the electron beam. 4 refs., 5 figs

  17. Study of plasma meniscus and beam halo in negative ion sources using three dimension in real space and three dimension in velocity space particle in cell model

    International Nuclear Information System (INIS)

    Our previous study by two dimension in real space and three dimension in velocity space-particle in cell model shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources. The negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. The purpose of this study is to verify this mechanism with the full 3D model. It is shown that the above mechanism is essentially unchanged even in the 3D model, while the fraction of the beam halo is significantly reduced to 6%. This value reasonably agrees with the experimental result

  18. Study of plasma meniscus and beam halo in negative ion sources using three dimension in real space and three dimension in velocity space particle in cell model

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, S., E-mail: nishioka@ppl.appi.keio.ac.jp; Goto, I.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [School of Natural and Living Sciences Education, Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Fukano, A. [Toshiba, 33 Isogo-chou, Isogo-ku, Yokohama-shi, Kanagawa 235-001 (Japan)

    2014-02-15

    Our previous study by two dimension in real space and three dimension in velocity space-particle in cell model shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources. The negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. The purpose of this study is to verify this mechanism with the full 3D model. It is shown that the above mechanism is essentially unchanged even in the 3D model, while the fraction of the beam halo is significantly reduced to 6%. This value reasonably agrees with the experimental result.

  19. Construction and commissioning of a hadronic test-beam calorimeter to validate the particle-flow concept at the ILC

    International Nuclear Information System (INIS)

    This thesis discusses research and development studies performed for a hadronic calorimeter concept for the International Linear Collider (ILC). The requirements for a detector for the ILC are de ned by the particle-ow concept in which the overall detector performance for jet reconstruction is optimised by reconstructing each particle individually. The calorimeter system has to have unprecedented granularity to ful l the task of shower separation. The validation of the shower models used to simulate the detector performance is mandatory for the design and optimisation of the ILC detector. The construction and operation of a highly granular test-beam system will serve as a tool for this validation. This motivates the urgent need of research and development on calorimeter prototypes. One possible realisation of the hadronic calorimeter is based on a sampling structure of steel and plastic scintillator with analogue readout, where the sensitive scintillator layers are divided into tiles. A newly developed silicon based photo-detector (SiPM) o ers the possibilities to design such a system. The SiPM is a multi-pixel avalanche photo-diode operated in Geiger mode. Due to its small dimensions it is possible to convert the light produced in the calorimeter to an electronic signal already inside the calorimeter volume. The basic developments on scintillator, tile and photo-detector studies provide the basis for prototype construction. The main part of this thesis will discuss the construction and rst commissioning of an analogue hadronic calorimeter prototype consisting of 8000 channels read out with SiPMs. The smallest calorimeter unit is the tile system including the SiPM. The production and characterisation chain of this unit is an essential step in the construction of a large scale prototype. These basic units are arranged on readout layers, which are already a multi-channel system of 200 channels. In addition, the new photo-detector requires dedicated readout

  20. Construction and commissioning of a hadronic test-beam calorimeter to validate the particle-flow concept at the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Groll, M.

    2007-06-15

    This thesis discusses research and development studies performed for a hadronic calorimeter concept for the International Linear Collider (ILC). The requirements for a detector for the ILC are de ned by the particle-ow concept in which the overall detector performance for jet reconstruction is optimised by reconstructing each particle individually. The calorimeter system has to have unprecedented granularity to ful l the task of shower separation. The validation of the shower models used to simulate the detector performance is mandatory for the design and optimisation of the ILC detector. The construction and operation of a highly granular test-beam system will serve as a tool for this validation. This motivates the urgent need of research and development on calorimeter prototypes. One possible realisation of the hadronic calorimeter is based on a sampling structure of steel and plastic scintillator with analogue readout, where the sensitive scintillator layers are divided into tiles. A newly developed silicon based photo-detector (SiPM) o ers the possibilities to design such a system. The SiPM is a multi-pixel avalanche photo-diode operated in Geiger mode. Due to its small dimensions it is possible to convert the light produced in the calorimeter to an electronic signal already inside the calorimeter volume. The basic developments on scintillator, tile and photo-detector studies provide the basis for prototype construction. The main part of this thesis will discuss the construction and rst commissioning of an analogue hadronic calorimeter prototype consisting of 8000 channels read out with SiPMs. The smallest calorimeter unit is the tile system including the SiPM. The production and characterisation chain of this unit is an essential step in the construction of a large scale prototype. These basic units are arranged on readout layers, which are already a multi-channel system of 200 channels. In addition, the new photo-detector requires dedicated readout