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1

Plasma acceleration of particle beams  

SciTech Connect

Plasmas, being fully ionized gases, are immune from electrical breakdown and so can support ultra-high accelerating fields (order GeV/cm) in the form of relativistic plasma waves. Several schemes to excite these waves and use them for particle acceleration are reviewed in this article. These include the beat wave accelerator (laser driven) and the plasma wakefield transformer (particle beam driven). In addition, the possible use of plasmas to provide strong final focusing of beams (the plasma lens) is described.

Katsouleas, T.; Dawson, J. M.

1989-04-05

2

Pulsed power accelerators for particle beam fusion  

SciTech Connect

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

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

1980-01-01

3

Toward automatic control of particle accelerator beams  

SciTech Connect

We describe a program aiming toward automatic control of particle accelerator beams. A hybrid approach is used, combining knowledge- based system programming techniques and traditional numerical simulations. We use an expert system shell for the symbolic processing and have incorporated the FORTRAN beam optics code TRANSPORT for numerical simulation. The paper discusses the symbolic model we built, the reasoning components, how the knowledge base accesses information from an operating beamline, and the experience gained in merging the two worlds of numeric and symbolic processing. We also discuss plans for a future real-time system. 6 refs., 6 figs.

Schultz, D.E.; Silbar, R.R.

1988-01-01

4

Characterisation of electron beams from laser-driven particle accelerators  

NASA Astrophysics Data System (ADS)

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

Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A.

2012-12-01

5

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOEpatents

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow throughout the assembly.

Maschke, Alfred W. (East Moriches, NY)

1985-01-01

6

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOEpatents

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow through the assembly.

Maschke, A.W.

1984-04-16

7

Applications of laser-accelerated particle beams for radiation therapy  

NASA Astrophysics Data System (ADS)

Proton beams are more advantageous than high-energy photons and electrons for radiation therapy because of their finite penetrating range and the Bragg peak near the end of their range, which have been utilized to achieve better dose conformity to the treatment target allowing for dose escalation and/or hypofractionation to increase local tumor control, reduce normal tissue complications and/or treatment time/cost. Proton therapy employing conventional particle acceleration techniques is expensive because of the large accelerators and treatment gantries that require excessive space and shielding. Compact proton acceleration systems are being sought to improve the cost-effectiveness for proton therapy. This paper reviews the physics principles of laser-proton acceleration and the development of prototype laserproton therapy systems as a solution for widespread applications of advanced proton therapy. The system design, the major components and the special delivery techniques for energy and intensity modulation are discussed in detail for laser-accelerated proton therapy.

Ma, C.-M.; Fourkal, E.; Li, J. S.; Veltchev, I.; Luo, W.; Fan, J. J.; Lin, T.; Tafo, A.

2011-05-01

8

Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data  

SciTech Connect

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.

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

9

Beam-beam simulation code BBSIM for particle accelerators  

SciTech Connect

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.

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

2011-01-01

10

BEAM DYNAMICS: Conceptual and technological evolutions of particle accelerators  

NASA Astrophysics Data System (ADS)

We give here an ordered list of all types of particle accelerators and exhibit how each type evolves conceptually and/or technologically from the preceding. This is in contrast to the usual “history of particle accelerators" in which unrelated accelerator types are listed in the chronological order. It is hoped that this discussion and understanding of the rationale and logic in the evolution of one accelerator type to the next will help to educe future inventions.

Lee, Teng C.

2009-06-01

11

Direct particle acceleration by two identical crossed radially polarized laser beams  

SciTech Connect

Electrons and {alpha} particles injected midway between two ultrahigh intensity crossed laser beams of radial polarization are shown to be accelerated in vacuum to several gigaelectron volts and to have average energy gradients in excess of 150 GeV/m. A unique model of the crossing beams is suggested, which maximizes the particle energy gain and minimizes the particle-beam diffraction.

Salamin, Yousef I. [Department of Physics, American University of Sharjah, P.O. Box 26666, Sharjah (United Arab Emirates)

2010-07-15

12

Radiation Environment and Shielding Requirements for the Sandia Particle-Beam Fusion Accelerator PBFA-II.  

National Technical Information Service (NTIS)

The Sandia National Laboratories Particle Beam Fusion Accelerator PBFA-II is expected to produce significant amounts of penetrating radiation. The present study considers a postulated operational scenario for the accelerator and determines the amount of s...

S. A. Dupree

1982-01-01

13

Particle-beam accelerators for radiotherapy and radioisotopes  

NASA Astrophysics Data System (ADS)

The philosophy used in developing the PIGMI (pion generator for medical irradiation) 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 accelerator. This allowed the elimination of the large, complicated ion source used in previous ion accelerators, and 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 are described.

Boyd, T. J., Jr.; Crandall, K. R.; Hamm, R. W.; Hansborough, L. D.; Hoeberling, R. F.; Jameson, R. A.; Knapp, E. A.; Mueller, D. W.; Potter, J. M.; Stokes, R. H.

14

Numerical simulations of intense charged particle beam propagation in a dielectric wakefield accelerator  

Microsoft Academic Search

The propagation of an intense electron beam through a long dielectric tube is a critical issue for the success of the dielectric wakefield acceleration scheme. Due to the head-tail instability, a high current charged particle beam cannot propagate long distance without external focusing. In this paper we examine the beam handling and control problem in the dielectric wakefield accelerator. We

W. Gai; A. D. Kanareykin; A. L. Kustov; J. Simpson

1995-01-01

15

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

NASA Astrophysics Data System (ADS)

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.

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

2010-11-01

16

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

SciTech Connect

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.

Schroeder, C. B.; Esarey, E.; Benedetti, C.; Toth, Cs.; Geddes, C. G. R.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2010-11-04

17

Particle-beam accelerators for radiotherapy and radioisotopes  

SciTech Connect

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.

Boyd, T.J.; Crandall, K.R.; Hamm, R.W.

1981-01-01

18

Interactive visualization of particle beams for accelerator design  

SciTech Connect

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.

Wilson, Brett; Ma, Kwan-Liu; Qiang, Ji; Ryne, Robert

2002-01-15

19

Plasma Opening Switch Development for the Particle Beam Fusion Accelerator II (PBFA II)  

Microsoft Academic Search

We have conducted plasma opening switch (POS) experiments on Sandia National Laboratories' new Particle Beam Fusion 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

R. W. Stinnett; D. H. Mcdaniel; G. E. Rochau; W. B. Moore; E. W. Gray; T. J. Renk; H. N. Woodall; T. W. Hussey; S. S. Payne; R. J. Commisso; J. M. Grossmann; D. D. Hinshelwood; R. A. Meger; J. M. Neri; W. F. Oliphant; P. F. Ottinger; B. V. Weber

1987-01-01

20

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

SciTech Connect

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

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

1993-11-01

21

Plasmas in particle accelerators: the warm-beam equilibria  

SciTech Connect

For a complete set of equilibrium particle densities and temperature, the corresponding distribution functions including space charge effects are provided through solution of the inverse equilibrium problem. An accompanying orbit theory shows that the projected transverse rosette orbit can be analyzed into a circular rotation (drift) and a betatron-vortex gyration. In the presence of more general beam density profiles, the betatron vortex gyrations assume an elliptical rather than circular shape.

Mark, J.W.K.; Smith, L.

1981-04-07

22

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

Microsoft Academic Search

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

J. J. Barnard; S. M. Lund

2008-01-01

23

Low energy beam transport for facility for rare isotope beams driver linear particle accelerator.  

PubMed

The driver linac for the facility for rare isotope beams (FRIB) will provide a wide range of primary ion beams for nuclear physics research. The linac will be capable of accelerating a uranium beam to an energy of up to 200 Mev?u and delivering it to a fragmentation target with a maximum power of 400 kW. Stable ion beams will be produced by a high performance electron cyclotron resonance ion source operating at 28 GHz. The ion source will be located on a high voltage platform to reach an initial beam energy of 12 keV?u. After extraction, the ion beam will be transported vertically down to the linac tunnel in a low energy beam transport (LEBT) system and injected into a radio frequency quadrupole (RFQ) operating at a frequency of 80.5 MHz. To meet the beam power requirements, simultaneous acceleration of two-charge states will be used for heavier ions (?Xe). This paper presents the layout of the FRIB LEBT and the beam dynamics in the LEBT. In particular, simulation and design of the beam line section before charge state selection will be detailed. The need to use an achromatic design for the charge state selection system and the advantage of an ion beam collimation system to limit the emittance of the beam injected into the RFQ will be discussed in this paper. PMID:22380310

Sun, L T; Leitner, D; Machicoane, G; Pozdeyev, E; Smirnov, V; Vorozhtsov, S B; Winklehner, D; Zhao, Q

2012-02-01

24

Low energy beam transport for facility for rare isotope beams driver linear particle accelerator  

NASA Astrophysics Data System (ADS)

The driver linac for the facility for rare isotope beams (FRIB) will provide a wide range of primary ion beams for nuclear physics research. The linac will be capable of accelerating a uranium beam to an energy of up to 200 Mev/u and delivering it to a fragmentation target with a maximum power of 400 kW. Stable ion beams will be produced by a high performance electron cyclotron resonance ion source operating at 28 GHz. The ion source will be located on a high voltage platform to reach an initial beam energy of 12 keV/u. After extraction, the ion beam will be transported vertically down to the linac tunnel in a low energy beam transport (LEBT) system and injected into a radio frequency quadrupole (RFQ) operating at a frequency of 80.5 MHz. To meet the beam power requirements, simultaneous acceleration of two-charge states will be used for heavier ions (>=Xe). This paper presents the layout of the FRIB LEBT and the beam dynamics in the LEBT. In particular, simulation and design of the beam line section before charge state selection will be detailed. The need to use an achromatic design for the charge state selection system and the advantage of an ion beam collimation system to limit the emittance of the beam injected into the RFQ will be discussed in this paper.

Sun, L. T.; Leitner, D.; Machicoane, G.; Pozdeyev, E.; Smirnov, V.; Vorozhtsov, S. B.; Winklehner, D.; Zhao, Q.

2012-02-01

25

Low energy beam transport for facility for rare isotope beams driver linear particle accelerator  

SciTech Connect

The driver linac for the facility for rare isotope beams (FRIB) will provide a wide range of primary ion beams for nuclear physics research. The linac will be capable of accelerating a uranium beam to an energy of up to 200 Mev/u and delivering it to a fragmentation target with a maximum power of 400 kW. Stable ion beams will be produced by a high performance electron cyclotron resonance ion source operating at 28 GHz. The ion source will be located on a high voltage platform to reach an initial beam energy of 12 keV/u. After extraction, the ion beam will be transported vertically down to the linac tunnel in a low energy beam transport (LEBT) system and injected into a radio frequency quadrupole (RFQ) operating at a frequency of 80.5 MHz. To meet the beam power requirements, simultaneous acceleration of two-charge states will be used for heavier ions ({>=}Xe). This paper presents the layout of the FRIB LEBT and the beam dynamics in the LEBT. In particular, simulation and design of the beam line section before charge state selection will be detailed. The need to use an achromatic design for the charge state selection system and the advantage of an ion beam collimation system to limit the emittance of the beam injected into the RFQ will be discussed in this paper.

Sun, L. T.; Leitner, D.; Machicoane, G.; Pozdeyev, E.; Winklehner, D.; Zhao, Q. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Smirnov, V.; Vorozhtsov, S. B. [Joint Institute for Nuclear Research, Dubna, Moscow 141980 (Russian Federation)

2012-02-15

26

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

SciTech Connect

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 neutron sources, nuclear waste transmutation, etc.

Barnard, J.J.; Lund, S.M.

2008-05-30

27

Acceleration of energetic particles by whistler waves in active space experiment with charged particle beams injection  

NASA Astrophysics Data System (ADS)

Results of energetic particle spectra perturbations registered on subsatellite Magion-3 during simultaneous injection of electron and xenon ion beams from the Intercosmos-25 (IK-25) satel-lite are discussed. One of the specific feature of this experiment (orbit 201,202) was that the charged particle flows were injected in the same direction along the magnetic field lines thereby produced the oblique beam-into-beam injection. Appearance of energetic electron and ion flux disturbances may be caused by the interaction of charged particles with whistler or alfven waves excited during beams injection. Electromagnetic waves excitation in these frequency ranges depends on a large variety of beam and plasma parameters for such configuration of injections. First of all, for the whistler waves amplification the relative weak magnetic field and a sufficiently small thermal longitudinal divergence of beam electrons are needed. Beam-plasma instability development does not contribute to the excitation of electromagnetic waves due to the smoothing of the beam particle distribution. The growth rates of the whistler and potential plasma waves are calculated for different electron beam models during modulated/unmodulated regimes of injection. This allows one to study the energetic charged particle spectra (electrons and protons) registered on Magion-3 at rather far distances from the mother IK-25 satellite in dependence of the whistler wave growth rates via normal Doppler effect for the different resonance detunings, propagation angles, and other beam/plasma parameters.

Baranets, Nikolai; Ruzhin, Yuri; Matisin, Jan; Erokhin, Nikolai; Afonin, Valeri; Vojta, Jaroslav; Smilauer, Jan

28

PBFA (Particle Beam Fusion Accelerator) II: The Pulsed Power Characterization Phase.  

National Technical Information Service (NTIS)

The Particle Beam Fusion Accelerator II, PBFA II, is now the largest pulsed power device in operation. This paper summarizes its first year and a half of operation for the Department of Energy (DOE) Inertial Confinement Fusion (ICF) program. Thirty-six se...

T. H. Martin B. N. Turman S. A. Goldstein J. M. Wilson D. L. Cook

1987-01-01

29

Target diagnostics for intense lithium ion hohlraum experiments on Particle Beam Fusion Accelerator II  

Microsoft Academic Search

A review of the diagnostics used at Sandia National Laboratories to measure the parameters of intense lithium ion-beam hohlraum target experiments on Particle Beam Fusion Accelerator II will be presented. This diagnostic package contains an extensive suite of x-ray spectral and imaging diagnostics that enable measurements of target temperature and x-ray output. The x-ray diagnostics include time-integrated and time-resolved pinhole

R. J. Leeper; J. E. Bailey; A. L. Carlson; G. A. Chandler; M. S. Derzon; R. J. Dukart; D. E. Hebron; J. A. Hunter; L. P. Mix; A. R. Moats; T. J. Nash; W. R. Olson; P. D. Rockett; C. L. Ruiz; J. A. Torres; R. W. Olsen; T. L. Barber; P. W. Lake; F. A. Schmidlapp

1995-01-01

30

Plasma opening switch experiments on the Particle Beam Accelerator II  

Microsoft Academic Search

Summary form only. The authors have developed and tested three different plasma-opening switch (POS) designs that use magnetic fields to control and confine the injected plasma. All three configurations couple current efficiently to a 5-? electron beam diode. In the first switch, a plasma generated by flashboard sources is injected into the 20-? magnetically insulated transmission line through six equally

M. A. Sweeney; D. H. McDaniel; C. W. Mendel; G. E. Rochau; W. B. S. Moore; G. R. Mowrer; W. W. Simpson; D. M. Zagar; T. Grasser; C. D. McDougal

1989-01-01

31

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

SciTech Connect

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 scientific data mining is increasingly considered. In plasma simulations, Bagherjeiran et al. presented a comprehensive report on applying graph-based techniques for orbit classification. They used the KAM classifier to label points and components in single and multiple orbits. Love et al. conducted an image space analysis of coherent structures in plasma simulations. They used a number of segmentation and region-growing techniques to isolate regions of interest in orbit plots. Both approaches analyzed particle accelerator data, targeting the system dynamics in terms of particle orbits. However, they did not address particle dynamics as a function of time or inspected the behavior of bunches of particles. Ruebel et al. addressed the visual analysis of massive laser wakefield acceleration (LWFA) simulation data using interactive procedures to query the data. Sophisticated visualization tools were provided to inspect the data manually. Ruebel et al. have integrated these tools to the visualization and analysis system VisIt, in addition to utilizing efficient data management based on HDF5, H5Part, and the index/query tool FastBit. In Ruebel et al. proposed automatic beam path analysis using a suite of methods to classify particles in simulation data and to analyze their temporal evolution. To enable researchers to accurately define particle beams, the method computes a set of measures based on the path of particles relative to the distance of the particles to a beam. To achieve good performance, this framework uses an analysis pipeline designed to quickly reduce the amount of data that needs to be considered in the actual path distance computation. As part of this process, region-growing methods are utilized to detect particle bunches at single time steps. Efficient data reduction is essential to enable automated analysis of large data sets as described in the next section, where data reduction methods are steered to the particular requirements of our clustering analysis. Previously, we have described the application of a set of algorithms to automate the data analys

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

32

Quantum Ground State and Minimum Emittance of a Fermionic Particle Beam in a Circular Accelerator  

NASA Astrophysics Data System (ADS)

In the usual parameter regime of accelerator physics, particle ensembles can be treated as classical. If we approach a regime where epsilon _x epsilon _y epsilon _s approx N_{particles} ? _{Compton}^3, however, the granular structure of quantum-mechanical phase space becomes a concern. In particular, we have to consider the Pauli exclusion principle, which will limit the minimum achievable emittance for a beam of fermions. We calculate these lowest emittances for the cases of bunched and coasting beams at zero temperature and their first-order change rate at finite temperature.

Kabel, Andreas C.

2002-04-01

33

Test of pixel detectors for laser-driven accelerated particle beams  

NASA Astrophysics Data System (ADS)

Laser-driven accelerated (LDA) particle beams have due to the unique acceleration process very special properties. In particular they are created in ultra-short bunches of high intensity exceeding more than 107 \\frac{particles}{cm^{2} \\cdot ns} per bunch. Characterization of these beams is very limited with conventional particle detectors. Non-electronic detectors such as imaging plates or nuclear track detectors are, therefore, conventionally used at present. Moreover, all these detectors give only offline information about the particle pulse position and intensity as they require minutes to hours to be processed, calling for a new highly sensitive online device. Here, we present tests of different pixel detectors for real time detection of LDA ion pulses. Experiments have been performed at the Munich 14MV Tandem accelerator with 8-20 MeV protons in dc and pulsed beam, the latter producing comparable flux as a LDA ion pulse. For detection tests we chose the position-sensitive quantum-counting semiconductor pixel detector Timepix which also provides per-pixel energy- or time-sensitivity. Additionally other types of commercially available pixel detectors are being evaluated such as the RadEye™1, a large area (25 x 50 mm2) CMOS image sensor. All of these devices are able to resolve individual ions with high spatial- and energy-resolution down to the level of ?m and tens of keV, respectively. Various beam delivering parameters of the accelerator were thus evaluated and verified. The different readout modes of the Timepix detector which is operated with an integrated USB-based readout interface allow online visualization of single and time-integrated events. Therefore Timepix offers the greatest potential in analyzing the beam parameters.

Reinhardt, S.; Granja, C.; Krejci, F.; Assmann, W.

2011-12-01

34

Acceleration of energetic particles by whistler waves in active space experiment with charged particle beams injection  

NASA Astrophysics Data System (ADS)

In this paper the investigation of wave-particle interaction during simultaneous injection of electron and xenon ion beams from the satellite Intercosmos-25 (IK-25) carried out using the data of the double satellite system with subsatellite Magion-3 (APEX). Results of active space experiment devoted to the beam-plasma instability are partially presented in the paper Baranets et al. (2007). A specific feature of the experiment carried out in orbits 201, 202 was that charged particle flows were injected in the same direction along the magnetic field lines B0 so the oblique beam-into-beam injection have been produced. Results of the beam-plasma interaction for this configuration were registered by scientific instruments mounted on the station IK-25 and Magion-3 subsatellite. Main attention is paid to study the electromagnetic and longitudinal waves excitation in different frequency ranges and the energetic electron fluxes disturbed due to wave-particle interaction with whistler waves. The whistler wave excitation on the 1st electron cyclotron harmonic via normal Doppler effect during electron beam injection in ionospheric plasma are considered.

Baranets, Nikolai; Ruzhin, Yuri; Erokhin, Nikolai; Afonin, Valeri; Vojta, Jaroslav; Šmilauer, Jan; Kudela, Karel; Matišin, Jan; Ciobanu, Mircea

2012-03-01

35

Thin Fiber Scintillation Counter for Determining Particle Beam Distributions in Accelerators  

Microsoft Academic Search

Thin fiber scintillation counters for studying particle beams in ; accelerators were developed using small plastic scintillation fibers made for use ; in high-energy physics. A fiber of 0.5-mm diameter or less and 1 to 10 cm long ; is mounted on a long thin (0.5-mm diameter and 20 ft long) two-layer glass pipe; ; the pipe serves as a

R. C. Jopson; R. E. Wright; Hans Mark

1960-01-01

36

Artificial intelligence research in particle accelerator control systems for beam line tuning  

SciTech Connect

Tuning particle accelerators is time consuming and expensive, with a number of inherently non-linear interactions between system components. Conventional control methods have not been successful in this domain and the result is constant and expensive monitoring of the systems by human operators. This is particularly true for the start-up and conditioning phase after a maintenance period or an unexpected fault. In turn, this often requires a step-by-step restart of the accelerator. Surprisingly few attempts have been made to apply intelligent accelerator control techniques to help with beam tuning, fault detection, and fault recovery problems. The reason for that might be that accelerator facilities are rare and difficult to understand systems that require detailed expert knowledge about the underlying physics as well as months if not years of experience to understand the relationship between individual components, particularly if they are geographically disjoint. This paper will give an overview about the research effort in the accelerator community that has been dedicated to the use of artificial intelligence methods for accelerator beam line tuning.

Pieck, Martin [Los Alamos National Laboratory

2008-01-01

37

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

SciTech Connect

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.

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

1999-11-13

38

Development of the laser evaporation ion source for lithium beam generation on the Particle Beam Fusion Accelerator (PBFA-II)  

SciTech Connect

The Laser Evaporation Ion Source (LEVIS) active lithium ion source has been developed for use on the focusing ion diode operated on the 10 TW Particle Beam Fusion Accelerator-II (PBFA-II) [J. P. VanDevender and D. L. Cook, Science {bold 232}, 831 (1986)] at Sandia National Laboratories. The source configuration consists of two laser pulses impinging on a heated (200 {degree}C) thin-film LiAg layer on the anode surface. A short-pulse Nd:YAG laser creates a high-density vapor, which is then ionized by a long-pulse dye laser using the LIBORS (laser ionization based on resonant saturation) ionization method. Small-scale experiments determined that this dual laser-based approach can produce a source plasma of adequate density and confinement for acceleration and transport. Hardware modifications were undertaken to correct problems of premature impedance collapse and lack of beam lithium seen on previous PBFA-II experiments. As much as 85 kJ of Li is measured at the beam focus, but the source may not have been operating in a fully active (i.e., preformed) manner. Focusing performance appears superior to a passive LiF ion source operated on PBFA-II with the same magnetic field topology. {copyright} {ital 1999 American Institute of Physics.}

Renk, T.J.; Tisone, G.C.; Adams, R.G.; Johnson, D.J.; Ruiz, C.L. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Cooper, G.W. [University of New Mexico, Albuquerque, New Mexico 87131 (United States)

1999-09-01

39

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

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

40

Particle-accelerator decommissioning  

SciTech Connect

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

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

1979-12-01

41

New techniques for particle accelerators  

SciTech Connect

A review is presented of the new techniques which have been proposed for use in particle accelerators. Attention is focused upon those areas where significant progress has been made in the last two years--in particular, upon two-beam accelerators, wakefield accelerators, and plasma focusers. 26 refs., 5 figs., 1 tab.

Sessler, A.M.

1990-06-01

42

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

Microsoft Academic Search

We present an object-oriented three-dimensional parallel particle-in-cell (PIC) code for simulation of beam dynamics in linear accelerators (linacs). An important feature of this code is the use of split-operator methods to integrate single-particle magnetic optics techniques with parallel PIC techniques. By choosing a splitting scheme that separates the self-fields from the complicated externally applied fields, we are able to utilize

Ji Qiang; Robert D. Ryne; Salman Habib; Viktor Decyk

2000-01-01

43

Electrostatic Wire Stabilizing a Charged Particle Beam.  

National Technical Information Service (NTIS)

In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it b...

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

1983-01-01

44

Means for the focusing and acceleration of parallel beams of charged particles  

DOEpatents

Apparatus for focusing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The array may be assembled from a single component which comprises a support plate containing uniform rows of poles. Each pole is separated by a hole through the plate designed to pass a beam. Two such plates may be positioned with their poles intermeshed to form a plurality of quadrupoles.

Maschke, Alfred W. (East Moriches, NY)

1982-09-21

45

Means for the focusing and acceleration of parallel beams of charged particles. [Patent application  

DOEpatents

Apparatus for focusing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The array may be assembled from a single component which comprises a support plate containing uniform rows of poles. Each pole is separated by a hole through the plate designed to pass a beam. Two such plates may be positioned with their poles intermeshed to form a plurality of quadrupoles.

Maschke, A.W.

1980-09-23

46

Optical transition radiation used in the diagnostic of low energy and low current electron beams in particle accelerators  

SciTech Connect

Optical transition radiation (OTR) plays an important role in beam diagnostics for high energy particle accelerators. Its linear intensity with beam current is a great advantage as compared to fluorescent screens, which are subject to saturation. Moreover, the measurement of the angular distribution of the emitted radiation enables the determination of many beam parameters in a single observation point. However, few works deals with the application of OTR to monitor low energy beams. In this work we describe the design of an OTR based beam monitor used to measure the transverse beam charge distribution of the 1.9-MeV electron beam of the linac injector of the IFUSP microtron using a standard vision machine camera. The average beam current in pulsed operation mode is of the order of tens of nano-Amps. Low energy and low beam current make OTR observation difficult. To improve sensitivity, the beam incidence angle on the target was chosen to maximize the photon flux in the camera field-of-view. Measurements that assess OTR observation (linearity with beam current, polarization, and spectrum shape) are presented, as well as a typical 1.9-MeV electron beam charge distribution obtained from OTR. Some aspects of emittance measurement using this device are also discussed.

Silva, T. F.; Bonini, A. L.; Lima, R. R.; Maidana, N. L.; Malafronte, A. A.; Pascholati, P. R.; Vanin, V. R.; Martins, M. N. [Institute of Physics, University of Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil)

2012-09-15

47

An object-oriented parallel particle-in-cell code for beam dynamics simulation in linear accelerators  

Microsoft Academic Search

In this paper, we present an object-oriented three- dimensional parallel particle-in-cell code for beam dynam- ics 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.

J. Qiang; R. D. Ryne; S. Habib; V. Decyk

1999-01-01

48

Acceleration and Compression of Charged Particle Bunches Using Counter-Propagating Laser Beams  

SciTech Connect

The nonlinear interaction between counter-propagating laser beams in a plasma results in the generation of large (enhanced) plasma wakes. The two beams need to be slightly detuned in frequency, and one of them has to be ultra-short (shorter than a plasma period). Thus produced wakes have a phase velocity close to the speed of light and can be used for acceleration and compression of charged bunches. The physical mechanism responsible for the enhanced wake generation is qualitatively described and compared with the conventional laser wakefield mechanism. The authors also demonstrate that, depending on the sign of the frequency difference between the lasers, the enhanced wake can be used as a ``snow-plow'' to accelerate and compress either positively or negatively charged bunches. This ability can be utilized in an electron-positron injector.

G. Shvets; N. J. Fisch; A. Pukhov

2000-10-17

49

Performance of plasma opening switches for the Particle Beam Fusion Accelerator II (PBFA II)  

SciTech Connect

During 1987 and 1988, Plasma Opening Switch (POS) experiments have been continued with the goal of providing voltage and power gain on the PBFA II ion beam accelerator at Sandia National Laboratories. The experiments have developed a POS that has a rugged plasma source, will open rapidly, and will couple to a high-impedance load. The initial erosion switch design with improved plasma uniformity does not couple to these loads. Therefore, we have abandoned further development of this switch for voltage and power gain. Three alternate designs have been developed, tested, and are found to have better performance with the high-impedance loads. These new switches employ magnetic fields to control and confine the injected plasma. A summary of the switch configurations, their theory of operation, and the experimental results is presented and discussed. 4 refs., 10 figs.

Rochau, G.E.; McDaniel, D.H.; Mendel, C.W.; Sweeney, M.A.; Moore, W.B.S.; Mowrer, G.R.; Simpson, W.W.; Zagar, D.M.; Grasser, T.; McDougal, C.D.

1989-01-01

50

Fusion reactions initiated by laser-accelerated particle beams in a laser-produced plasma  

NASA Astrophysics Data System (ADS)

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.

Labaune, C.; Baccou, C.; Depierreux, S.; Goyon, C.; Loisel, G.; Yahia, V.; Rafelski, J.

2013-10-01

51

Fusion reactions initiated by laser-accelerated particle beams in a laser-produced plasma.  

PubMed

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. PMID:24104859

Labaune, C; Baccou, C; Depierreux, S; Goyon, C; Loisel, G; Yahia, V; Rafelski, J

2013-01-01

52

Two-beam accelerator  

SciTech Connect

In the two-beam accelerator (TBA) concept, an electron linear accelerator structure is established in which two beams propagate. One is an intense low energy beam that is made to undergo free electron lasing to produce microwaves. These microwaves are then coupled to another part of the structure where they act to produce a high longitudinal electric gradient that is used to accelerate a second relatively low intensity electron beam to very high energies. The TBA was originally suggested by Sessler as a possible means for economically achieving linear collider energies of 100 GeV and above. Although still in a conceptual stage, the TBA is an inherently plausible concept that combines the free electron laser (FEL) with several well-known technologies - high current induction linacs, microwave waveguides, and traveling-wave linac structures - in a novel and interesting way. Two characteristics of the TBA that make it a particularly suitable candidate for achieving high energies are its ability to operate at higher frequencies than typical present-day linacs (say 30 GHz as compared with 3 GHz), and to be an efficient means for delivering power to a hitherto unattainable high-gradient structure (say 250 MV/m) that the higher frequency makes possible. These high accelerating gradients will permit much shorter linac structures for a given energy.

Selph, F.B.

1984-09-01

53

Focus on Accelerator and Beam Physics  

Microsoft Academic Search

For more than 50 years, particle accelerators have driven fundamental discoveries in many areas of scientific research. The discovery of elementary particles, the nature of fundamental forces and fields and the enormous increase of knowledge in nuclear physics would not have been possible without the progress of accelerator physics and technology in providing bright, intense and high energy beams of

Georg Hoffstaetter; Kwang-Je Kim; Ferdinand Willeke

2006-01-01

54

Numerical Fluid Simulation of a Charged Particle Beam with Applications to Collective Acceleration  

Microsoft Academic Search

The relativistic electron fluid momentum, continuity, and Maxwell's equations are used to model a magnetized pure electron plasma in a cylindrical conducting waveguide. Finite differencing is used in space, and the equations are numerically integrated in time. Eigenmodes of the beam\\/waveguide system are derived from the linearized equations in the beam frame with the assumption that the beam density is

Daniel Nicolos Koury Jr.

1992-01-01

55

Space charge compensation in laser particle accelerators  

NASA Astrophysics Data System (ADS)

Laser particle acceleration (LPA) involves the acceleration of particle beams by electromagnetic waves with relatively short wavelength compared with conventional radio-frequency systems. These short length scales raise the question whether space charge effects may be a limiting factor in LPA performance. This is analyzed in two parts of an accelerator system, the acceleration sections and the drift region of the prebuncher. In the prebuncher, space charge can actually be converted to an advantage for minimizing the energy spread. In the accelerator sections, the laser fields can compensate for space charge forces, but the compensation becomes weaker for high beam energy.

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

1999-07-01

56

Neutral particle beam intensity controller  

DOEpatents

A neutral beam intensity controller is provided for a neutral beam generator in which a neutral beam is established by accelerating ions from an ion source into a gas neutralizer. An amplitude modulated, rotating magnetic field is applied to the accelerated ion beam in the gas neutralizer to defocus the resultant neutral beam in a controlled manner to achieve intensity control of the neutral beam along the beam axis at constant beam energy. The rotating magnetic field alters the orbits of ions in the gas neutralizer before they are neutralized, thereby controlling the fraction of neutral particles transmitted out of the neutralizer along the central beam axis to a fusion device or the like. The altered path or defocused neutral particles are sprayed onto an actively cooled beam dump disposed perpendicular to the neutral beam axis and having a central open for passage of the focused beam at the central axis of the beamline. Virtually zero therough 100% intensity control is achieved by varying the magnetic field strength without altering the ion source beam intensity or its species yield.

Dagenhart, William K. (Oak Ridge, TN)

1986-01-01

57

Calculating Beam Breakup in Superconducting Linear Accelerators  

SciTech Connect

As the intensity of a particle beam passing through a linear accelerator is raised, interactions between particles play an increasingly prominent role in determining the overall dynamics of the beam. These many body effects, known collectively as beam breakup, tend to degrade the quality of the transported beam, and hence they must be calculated to accurately predict the evolution of the beam as it traverses the accelerator. Several codes which compute various collective effects have been developed and used to simulate the dynamics of beams passing through superconducting accelerator structures. All the codes use the same basic algorithm: the beam is tracked through elements giving the focusing forces on the particles, and at the appropriate locations in the linac, localized forces are impressed on the particles which model the electromagnetic interactions. Here, a difficulty is that the usual ''Coulomb'' interaction between particles is changed by the electromagnetic environment of the accelerator. By such calculations it has been shown that recirculating linear accelerators such as the one being built at the Continuous Electron Beam Accelerator Facility (CEBAF) should remain stable against multipass beam breakup instability as long as the average current does not exceed about 20 mA, that the beam quality at CEBAF will be degraded when the single bunch charge approaches 10{sup 9} electrons, and that the beam quality of superconducting linacs that are optimized for high current transport begins to decrease at around 10{sup 10} electrons per bunch. The latter result is of interest to individuals who would use superconducting linacs as beam sources for free electron lasers or for superconducting colliders for high energy physics research.

Geoffrey Krafft; Joseph Bisognano; Sharon Laubach

1990-02-09

58

Charged particle beams  

SciTech Connect

Theoretical and practical aspects of charged-particle beam devices are discussed in an introductory text and reference guide. Topics addressed include the phase-space description of charged-particle beams, beam emittance, beam-generated forces, electron and ion guns, high-power pulsed electron and ion diodes, paraxial beam transport with space charge, and high-current electron-beam transport under vacuum. Consideration is given to ion-beam neutralization, electron beams in plasmas, transverse instabilities, longitudinal instabilities, and the generation of radiation with electron beams. Extensive diagrams and graphs are provided. 111 refs.

Humphries, S. Jr.

1990-01-01

59

European particle accelerator conference  

SciTech Connect

This book contains the following topics: The LEP project, Superconducting RF cavities for accelerator application, Commissioning of super-ACO, Pulsed high-power beams, RF Power sources, Astrid, A storage ring for ions and electrons, Linear collider studies in Europe.

Tazzari, S.

1988-01-01

60

Particle acceleration in Blazars  

NASA Astrophysics Data System (ADS)

Understanding the variable emission of blazars observed with gamma-ray telescopes and Fermi has become a major challenge for theoretical models of particle acceleration. Here, we introduce a novel time-dependent emission model in which the maximum energy of particles is determined from a balance between Fermi type I and II acceleration energy gains and radiative energy losses, allowing for an explanation of both the characteristic spectral energy distribution of blazars and their intrinsic sub-hour variability. Additionally, we can determine the physical condition of the emitting plasma concerning its turbulence and typical shock speeds.

Weidinger, Matthias; Spanier, Felix

2011-06-01

61

Technique for Pulsing the Electron Beam of a van de Graaff Particle Accelerator.  

National Technical Information Service (NTIS)

The need for a pulsed high energy gamma source as a research tool, with the capability of changing the pulse profile, is filled by slightly modifying a Van de Graaff accelerator set up to run in a gnegative mode. The modification consists of triggering by...

G. Healey

1965-01-01

62

Beam Stop for Electron Accelerator Beam Characterisation  

Microsoft Academic Search

Electron linear accelerator applications involving the generation of hard X-rays frequently require accurate knowledge of the electron beam parameters. We developed a beam stop device which houses a tungsten Bremsstrahlung target and enables the electron beam current, energy and position to be monitored. The beam stop consisted of four plates. The first was a removable aluminium (Al) transmission plate. Then

Greg Roach; Vic Sharp; James Tickner; Josef Uher

2009-01-01

63

Beam stop for electron accelerator beam characterisation  

Microsoft Academic Search

Electron linear accelerator applications involving the generation of hard X-rays frequently require accurate knowledge of the electron beam parameters. We developed a beam stop device which houses a tungsten Bremsstrahlung target and enables the electron beam current, energy and position to be monitored.

Greg Roach; Vic Sharp; James Tickner; Josef Uher

2008-01-01

64

Particle Acceleration in Pulsar Magnetospheres.  

National Technical Information Service (NTIS)

The structure of pulsar magnetospheres and the acceleration mechanism for charged particles in the magnetosphere was studied, using a pulsar model which required large acceleration of the particles near the surface of the star. A theorem was developed whi...

K. B. Baker

1978-01-01

65

IEC accelerator beam coordinate transformations for clinical Monte Carlo simulation from a phase space or full BEAMnrc particle source.  

PubMed

Monte Carlo simulation of clinical treatment plans require, in general, a coordinate transformation to describe the incident radiation field orientation on a patient phantom coordinate system. The International Electrotechnical Commission (IEC) has defined an accelerator coordinate system along with positive directions for gantry, couch and collimator rotations. In order to describe the incident beam's orientation with respect to the patient's coordinate system, DOSXYZnrc simulations often require transformation of the accelerator's gantry, couch and collimator angles to describe the incident beam. Similarly, versions of the voxelized Monte Carlo code (VMC(++)) require non-trivial transformation of the accelerator's gantry, couch and collimator angles to standard Euler angles ?, ?, ?, to describe an incident phase space source orientation with respect to the patient's coordinate system. The transformations, required by each of these Monte Carlo codes to transport phase spaces through a phantom, have been derived with a rotation operator approach. The transformations have been tested and verified against the Eclipse treatment planning system. PMID:21053115

Bush, Karl K; Zavgorodni, Sergei F

2010-11-05

66

Simple laser accelerator - Optics and particle dynamics  

NASA Astrophysics Data System (ADS)

When a laser is focused it develops a longitudinal component. This could be used to develop a laser particle accelerator. A lens waveguide array is discussed, and it is shown that such a system could generate high-energy particle beams. The possibility of using a 'diffraction-free' Bessel beam is discussed, and a possible configuration is suggested. To accelerate electrons from one to a few MeV seems possible using a well-focused, 1-J, 1-ps laser pulse. This would provide a simple proof-of-principle experiment. In order to accelerate heavier particles, such as protons, the injected particle beam would have to be ultrarelativistic such as that produced by the superconducting supercollider.

Scully, Marlan O.; Zubairy, M. S.

1991-08-01

67

Analysis of Gaussian beam and Bessel beam driven laser accelerators  

SciTech Connect

This paper presents a comparison of Gaussian and Bessel beam driven laser accelerators. The emphasis is on the vacuum beat wave accelerator (VBWA), employing two laser beams of differing wavelengths to impart a net acceleration to particles. Generation of Bessel beams by means of circular slits, holographic optical elements, and axicons is outlined and the image space fields are determined by making use of Huygens{close_quote} principle. Bessel beams{emdash}like Gaussian beams{emdash}experience a Guoy phase shift in the vicinity of a focal region, resulting in a phase velocity that exceeds {ital c}, the speed of light {ital in vacuo}. In the VBWA, by appropriate choice of parameters, the Guoy phases of the laser beams cancel out and the beat wave phase velocity equals {ital c}. The particle energy gain and beam quality are determined by making use of an analytical model as well as simulations. The analytical model{emdash}including the {bold v}{times}{bold B} interaction{emdash}predicts that for equal laser powers Gaussian and Bessel beams lead to identical energy gains. However, three-dimensional, finite-emittance simulations, allowing for detuning, transverse displacements, and including all the electromagnetic field components, show that the energy gain of a Gaussian beam driven VBWA exceeds that of a Bessel beam driven VBWA by a factor of 2{endash}3. The particle beam emerging from the interaction is azimuthally symmetric and collimated, with a relatively small angular divergence. A table summarizing the ratios of final energies, acceleration lengths, and gradients for a number of acceleration mechanisms is given. {copyright} {ital 1999} {ital The American Physical Society}

Hafizi, B.; Ganguly, A.K.; Moore, C.I. [Omega-P, Inc., P.O. Box 202008, New Haven, Connecticut 06520-2008 (United States); Ting, A.; Sprangle, P. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375-5346 (United States)

1999-10-01

68

Cooling of particle beams.  

National Technical Information Service (NTIS)

A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling wi...

A. M. Sessler

1994-01-01

69

Particle accelerator for inducing contained particle collisions  

US Patent & Trademark Office Database

A particle accelerator for inducing contained particle collisions. The particle accelerator includes two hollow dees of electrically conductive material which are separated and electrically insulated from each other. The dees are located between the poles of a strong magnet which generates a magnetic field through top and bottom sides of the dees. In addition, the dees are connected to an oscillator for providing an alternating voltage between the dees. The dees are located within a chamber containing a gas and/or vapor provided at a measurable pressure. Ions are accelerated in essentially spiral paths within the dees, and follow paths which may be both concentric and non-concentric with the dees whereby collisions are produced between accelerated ions and gas or vapor atoms contained within the chamber, as well as between pairs of accelerated ions following different paths. The particle collisions within the chamber produces neutrons, generates energy, and performs other useful functions associated with the interaction of particles.

2002-08-27

70

A laser-plasma accelerator producing monoenergetic electron beams  

Microsoft Academic Search

Particle accelerators are used in a wide variety of fields, ranging from medicine and biology to high-energy physics. The accelerating fields in conventional accelerators are limited to a few tens of MeVm-1, owing to material breakdown at the walls of the structure. Thus, the production of energetic particle beams currently requires large-scale accelerators and expensive infrastructures. Laser-plasma accelerators have been

J. Faure; Y. Glinec; A. Pukhov; S. Kiselev; S. Gordienko; E. Lefebvre; J.-P. Rousseau; F. Burgy; V. Malka

2004-01-01

71

Applications of pyroelectric particle accelerators  

NASA Astrophysics Data System (ADS)

The discovery of pyroelectric X-ray generation in 1992 by Brownridge has led to a recent surge of interest in the use of the pyroelectric effect as a means of producing useful radiation. By heating or cooling a pyroelectric crystal such as lithium tantalate (LiTaO3) in a vacuum, a potential on the order of 100 kV can be generated. This potential is great enough to eject electrons from the crystal for the production of characteristic or bremsstrahlung X-rays, or to cause field ionization near a tip mounted to the crystal. By using the combined fields of two polarized crystals, the acceleration potential can be doubled, with one crystal acting as a particle emitter and the other crystal serving as a target. Such a paired-crystal system was used to generate X-rays with energies of greater than 200 keV, and can be used to fluoresce the K shell of thorium (Z = 92). An alternative use of pyroelectric sources is the field ionization of a dilute gas. If the positively-charged crystal is used to ionize a deuterium gas, and the target crystal is coated with deuterated target, the deuterium ions can be accelerated into the target at high enough energy to cause D D fusion. Results verifying the production of D D fusion neutrons from a pyroelectric source will be presented. Future applications of pyroelectric accelerator technology, such as the use of the electron beam for materials testing, will also be discussed.

Geuther, Jeffrey A.; Danon, Yaron

2007-08-01

72

TOPICAL REVIEW: Plasma based charged-particle accelerators  

NASA Astrophysics Data System (ADS)

Studies of charged-particle acceleration processes remain one of the most important areas of research in laboratory, space and astrophysical plasmas. In this paper, we present the underlying physics and the present status of high gradient and high energy plasma accelerators. We will focus on the acceleration of charged particles to relativistic energies by plasma waves that are created by intense laser and particle beams. The generation of relativistic plasma waves by intense lasers or electron beams in plasmas is important in the quest for producing ultra-high acceleration gradients for accelerators. With the development of compact short pulse high brightness lasers and electron positron beams, new areas of studies for laser/particle beam-matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultra-high acceleration gradients. These include the plasma beat wave accelerator mechanism, which uses conventional long pulse (~100 ps) modest intensity lasers (I ~ 1014-1016 W cm-2), the laser wakefield accelerator (LWFA), which uses the new breed of compact high brightness lasers (<1 ps) and intensities >1018 W cm-2, the self-modulated LWFA concept, which combines elements of stimulated Raman forward scattering, and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches. In the ultra-high intensity regime, laser/particle beam-plasma interactions are highly nonlinear and relativistic, leading to new phenomena such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm-1 have been generated with particles being accelerated to 200 MeV over a distance of millimetre. Plasma wakefields driven by positron beams at the Stanford Linear Accelerator Center facility have accelerated the tail of the positron beam. In the near future, laser plasma accelerators will be producing GeV particles.

Bingham, R.; Mendonça, J. T.; Shukla, P. K.

2004-01-01

73

Superconducting cavities for particle accelerators  

Microsoft Academic Search

RF Superconductivity has become an important technology for particle accelerators for high energy physics, nuclear physics, and free electron lasers. More than 100 MVolts of Superconducting RF (SRF) cavities have been installed in accelerators for heavy ions and operated at gradients of 2-3 MV\\/m in excess of 105 hours. More than 500 MVolts are installed in electron accelerators and operated

H. Padamsee

1992-01-01

74

Recent progress in techniques utilized for particle accelerator  

NASA Astrophysics Data System (ADS)

Particle accelerators are widely used in scientific research and industry. Recently, techniques utilized for accelerator are developed rapidly in China. We briefly review the recent progress in this field and primarily focus on superconducting RF, innovative structures for particle production and acceleration and beam diagnosis. Several advanced compact user facilities are also introduced.

Liu, KeXin

2012-12-01

75

Investigation of Beam-RF Interactions in Twisted Waveguide Accelerating Structures Using Beam Tracking Codes  

SciTech Connect

Investigations of the RF properties of certain twisted waveguide structures show that they support favorable accelerating fields. This makes them potential candidates for accelerating cavities. Using the particle tracking code, ORBIT, We examine the beam - RF interaction in the twisted cavity structures to understand their beam transport and acceleration properties. The results will show the distinctive properties of these new structures for particle transport and acceleration, which have not been previously analyzed.

Holmes, Jeffrey A [ORNL; Zhang, Yan [ORNL; Kang, Yoon W [ORNL; Galambos, John D [ORNL; Hassan, Mohamed H [ORNL; Wilson, Joshua L [ORNL

2009-01-01

76

Safety training and safe operating procedures written for PBFA (Particle Beam Fusion Accelerator) II and applicable to other pulsed power facilities  

SciTech Connect

To ensure that work in advancing pulsed power technology is performed with an acceptably low risk, pulsed power research facilities at Sandia National Laboratories must satisfy general safety guidelines established by the Department of Energy, policies and formats of the Environment, Safety, and Health (ES and H) Department, and detailed procedures formulated by the Pulsed Power Sciences Directorate. The approach to safety training and to writing safe operating procedures, and the procedures presented here are specific to the Particle Beam Fusion Accelerator II (PBFA II) Facility but are applicable as guidelines to other research and development facilities which have similar hazards.

Donovan, G.L.; Goldstein, S.A.

1986-12-01

77

Experimental observations of in situ secondary electron yield reduction in the PEP-II particle accelerator beam line  

NASA Astrophysics Data System (ADS)

Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron damping ring (DR) of future linear colliders (LC) such as ILC and CLIC [1,2]. To test a series of promising possible electron cloud mitigation techniques as surface coatings and grooves, in the Positron low-energy ring (LER) of the PEP-II accelerator, we have installed several test vacuum chambers including (i) a special chamber to monitor the variation in the secondary electron yield of technical surface materials and coatings under the effect of ion, electron and photon conditioning in situ in the beam line (ii) chambers with grooves [3] in a straight magnetic-free section and (iii) coated chambers in a dedicated newly installed 4-magnet chicane [4] to study mitigations in a magnetic field region. In this paper, we describe the ongoing R&D effort to mitigate the electron cloud effect for the LC damping ring, focusing on the first experimental area and on results of the reduction in the secondary electron yield due to in situ conditioning.

Pivi, M. T. F.; Collet, G.; King, F.; Kirby, R. E.; Markiewicz, T.; Raubenheimer, T. O.; Seeman, J.; Le Pimpec, F.

2010-09-01

78

Particle acceleration by electromagnetic waves.  

PubMed

We consider the symmetry in the interaction of photons and electrons, which has led to a common description of electron and photon accelerations; effects such as photon Landau damping arise naturally from such a treatment. Intense electromagnetic waves can act as a photon mirror to charged particles. The subsequent acceleration is equivalent to the photon pulse accelerating electrons. During the interaction or reflection process, the charged particle can emit bursts of radiation similar to the radiation emitted from the particles during wave breaking of plasma waves. PMID:18218605

Bingham, R

2008-05-28

79

Soviet exoatmospheric neutral particle beam research  

SciTech Connect

This technical assessment was performed by a panel of eight U.S. scientists and engineers who are familiar with Soviet research through their own research experience, their knowledge of the published scientific literature and conference proceedings, and personal contacts with Soviet scientists and other foreign colleagues. Most of the technical components of a neutral particle beam generating system including the ion source, the accelerator, the accelerator radio frequency power supply, the beam conditioning and aiming system, and the beam neutralizer system are addressed. It does not address a number of other areas important to an exoatmospheric neutral beam system.

Leiss, J.E.; Abrams, R.H.; Ehlers, K.W.; Farrell, J.A.; Gillespie, G.H.; Jameson, R.A.; Keefe, D.; Parker, R.K.

1988-02-01

80

Particle Acceleration in Cosmic Plasmas  

SciTech Connect

This proceedings includes papers presented at the Bartol ResearchInstitute, on topics concerning particle acceleration in stellar, space andgalactic environments. Two of the papers from this proceedings have beenabstracted for the database. (AIP)

Zank, G.P.; Gaisser, T.K. (eds.) (Bartol Research Institute, theUniversity of Delaware, Newark, DE (United States))

1992-01-01

81

Lasers and new methods of particle acceleration  

SciTech Connect

There has been a great progress in development of high power laser technology. Harnessing their potential for particle accelerators is a challenge and of great interest for development of future high energy colliders. The author discusses some of the advances and new methods of acceleration including plasma-based accelerators. The exponential increase in sophistication and power of all aspects of accelerator development and operation that has been demonstrated has been remarkable. This success has been driven by the inherent interest to gain new and deeper understanding of the universe around us. With the limitations of the conventional technology it may not be possible to meet the requirements of the future accelerators with demands for higher and higher energies and luminosities. It is believed that using the existing technology one can build a linear collider with about 1 TeV center of mass energy. However, it would be very difficult (or impossible) to build linear colliders with energies much above one or two TeV without a new method of acceleration. Laser driven high gradient accelerators are becoming more realistic and is expected to provide an alternative, (more compact, and more economical), to conventional accelerators in the future. The author discusses some of the new methods of particle acceleration, including laser and particle beam driven plasma based accelerators, near and far field accelerators. He also discusses the enhanced IFEL (Inverse Free Electron Laser) and NAIBEA (Nonlinear Amplification of Inverse-Beamstrahlung Electron Acceleration) schemes, laser driven photo-injector and the high energy physics requirements.

Parsa, Z.

1998-02-01

82

Particle acceleration in binary systems  

SciTech Connect

Close binary systems can be efficient sources of magnetohydrodynamic oscillations. The energy expended in exciting these waves will serve to retard the orbital motion. Nonlinear interactions in the plasma surrounding a binary system could transform initial large-scale motions into pulsations of short wavelength. Intensive acceleration of energetic particles will occur under these conditions, and the particles could escape from the acceleration region by diffusion.

Dolginov, A.Z.; Urpin, V.A.

1978-07-01

83

Future Particle Accelerator Developments for Radiation Therapy  

NASA Astrophysics Data System (ADS)

During the last decade particle beam cancer therapy has seen a rapid increase in interest, and several new centers have been built, are currently under construction, or are in an advanced stage of planning. Typical treatment centers today consist of an accelerator capable of producing proton or ion beams in an energy range of interest for medical treatment, i.e. providing a penetration depth in water of about 30 cm, a beam delivery system to transport the produced beam to the patient treatment rooms, and several patient stations, allowing for an optimal usage of the continuously produced beam. This makes these centers rather large and consequently expensive. Only major hospital centers situated in an area where they can draw on a population of several million can afford such an installation. In order to spread the use of particle beam cancer therapy to a broader population base it will be necessary to scale down the facility size and cost. This can in principle be done by reducing the number of treatment rooms to one, eliminating the need of an elaborate beam delivery system, and thereby reducing the building size and cost. Such a change should be going in parallel with a reduction of the accelerator itself, and a number of approaches to this are currently being pursued. If successful, such developments could eventually lead to a compact system where all components would fit into a single shielded room, not much different in size from a typical radiation vault for radiotherapy with X-rays.

Holzscheiter, Michael H.; Bassler, Niels

84

Confined energy distribution for charged particle beams  

DOEpatents

A charged particle beam is formed to a relatively larger area beam which is well-contained and has a beam area which relatively uniformly deposits energy over a beam target. Linear optics receive an accelerator beam and output a first beam with a first waist defined by a relatively small size in a first dimension normal to a second dimension. Nonlinear optics, such as an octupole magnet, are located about the first waist and output a second beam having a phase-space distribution which folds the beam edges along the second dimension toward the beam core to develop a well-contained beam and a relatively uniform particle intensity across the beam core. The beam may then be expanded along the second dimension to form the uniform ribbon beam at a selected distance from the nonlinear optics. Alternately, the beam may be passed through a second set of nonlinear optics to fold the beam edges in the first dimension. The beam may then be uniformly expanded along the first and second dimensions to form a well-contained, two-dimensional beam for illuminating a two-dimensional target with a relatively uniform energy deposition. 8 figs., 2 tabs.

Jason, A.J.; Blind, B.

1989-09-29

85

Accelerated radioactive beams from REX-ISOLDE  

NASA Astrophysics Data System (ADS)

In 2001 the linear accelerator of the Radioactive beam EXperiment (REX-ISOLDE) delivered for the first time accelerated radioactive ion beams, at a beam energy of 2 MeV/u. REX-ISOLDE uses the method of charge-state breeding, in order to enhance the charge state of the ions before injection into the LINAC. Radioactive singly-charged ions from the on-line mass separator ISOLDE are first accumulated in a Penning trap, then charge bred to an /A/q<4.5 in an electron beam ion source (EBIS) and finally accelerated in a LINAC from 5 keV/u to energies between 0.8 and 2.2 MeV/u. Dedicated measurements with REXTRAP, the transfer line and the EBIS have been carried out in conjunction with the first commissioning of the accelerator. Thus the properties of the different elements could be determined for further optimization of the system. In two test beam times in 2001 stable and radioactive Na isotopes (23Na-26Na) have been accelerated and transmitted to a preliminary target station. There 58Ni- and 9Be- and 2H-targets have been used to study exited states via Coulomb excitation and neutron transfer reactions. One MINIBALL triple cluster detector was used together with a double sided silicon strip detector to detect scattered particles in coincidence with ?-rays. The aim was to study the operation of the detector under realistic conditions with ?-background from the ?-decay of the radioactive ions and from the cavities. Recently for efficient detection eight tripple Ge-detectors of MINIBALL and a double sided silicon strip detector have been installed. We will present the first results obtained in the commissioning experiments and will give an overview of realistic beam parameters for future experiments to be started in the spring 2002.

ISOLDE Collaboration; Kester, O.; Sieber, T.; Emhofer, S.; Ames, F.; Reisinger, K.; Reiter, P.; Thirolf, P. G.; Lutter, R.; Habs, D.; Wolf, B. H.; Huber, G.; Schmidt, P.; Ostrowski, A. N.; von Hahn, R.; Repnow, R.; Fitting, J.; Lauer, M.; Scheit, H.; Schwalm, D.; Podlech, H.; Schempp, A.; Ratzinger, U.; Forstner, O.; Wenander, F.; Cederkäll, J.; Nilsson, T.; Lindroos, M.; Fynbo, H.; Franchoo, S.; Bergmann, U.; Oinonen, M.; Äystö, J.; den Bergh, P. Van; Duppen, P. Van; Huyse, M.; Warr, N.; Weisshaar, D.; Eberth, J.; Jonson, B.; Nyman, G.; Pantea, M.; Simon, H.; Shrieder, G.; Richter, A.; Tengblad, O.; Davinson, T.; Woods, P. J.; Bollen, G.; Weissmann, L.; Liljeby, L.; Rensfelt, K. G.

2003-05-01

86

Computation applied to particle accelerator simulations  

SciTech Connect

The rapid growth in the power of large-scale computers has had a revolutionary effect on the study of charged-particle accelerators that is similar to the impact of smaller computers on everyday life. Before an accelerator is built, it is now the absolute rule to simulate every component and subsystem by computer to establish modes of operation and tolerances. We will bypass the important and fruitful areas of control and operation and consider only application to design and diagnostic interpretation. Applications of computers can be divided into separate categories including: component design, system design, stability studies, cost optimization, and operating condition simulation. For the purposes of this report, we will choose a few examples taken from the above categories to illustrate the methods and we will discuss the significance of the work to the project, and also briefly discuss the accelerator project itself. The examples that will be discussed are: (1) the tracking analysis done for the main ring of the Superconducting Supercollider, which contributed to the analysis which ultimately resulted in changing the dipole coil diameter to 5 cm from the earlier design for a 4-cm coil-diameter dipole magnet; (2) the design of accelerator structures for electron-positron linear colliders and circular colliding beam systems (B-factories); (3) simulation of the wake fields from multibunch electron beams for linear colliders; and (4) particle-in-cell simulation of space-charge dominated beams for an experimental liner induction accelerator for Heavy Ion Fusion. 8 refs., 9 figs.

Herrmannsfeldt, W.B. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)); Yan, Y.T. (Superconducting Super Collider Lab., Dallas, TX (United States))

1991-07-01

87

Applications of magnetized plasma to particle acceleration  

SciTech Connect

Magnetized plasma can be used as an accelerating structure capable of supporting large amplitude longitudinal fields which are externally driven by a high-frequency microwave source. Such structures can be used at very high frequencies (hundreds of gigahertz), placing them in the intermediate region between conventional (metallic) accelerators, and laser-driven plasma accelerators. They review two magnetic field configurations with respect to the direction of the particle beam propagation: (1) parallel magnetic field plus a helical undulator, and (2) perpendicular magnetic field. In the first configuration, plasma exhibits electromagnetically induced transparency (EIT) at the cyclotron frequency if the plasma frequency is equal to the electron cyclotron frequency. The second configuration corresponds to the inverse Cherenkov effect in magnetized plasma. In both cases, the group velocity of the accelerating plasma wave can be made very small, so that the incident electromagnetic wave is strongly compressed, resulting in the high accelerating gradient.

Shvets, Gennady; Wurtele, Jonathan S.; Hur, Min-Sup

2002-12-12

88

Particle acceleration at relativistic shocks.  

NASA Astrophysics Data System (ADS)

A brief review is given of the status of the theory of particle acceleration at relativistic shocks, indicating the importance of the effects which arise in oblique shocks. In the case of ultra-relativistic shocks, it is suggested that the main acceleration mechanism is shock-drift acceleration, because even a slight obliquity of the magnetic field suffices to inhibit the ability of a particle to cross and recross the shock front. However, for mildly relativistic flows in which the magnetic field is almost parallel to the shock normal the first order Fermi mechanism can be effective. In this case it is possible to estimate the efficiency of acceleration by considering the back reaction of particles on the fluid. The results of an investigation of the stationary solutions of this nonlinear problem show interesting deviations from the nonrelativistic results even at modest shock speeds (?c/3).

Kirk, J. G.

89

FOCUSING AND ACCELERATION OF BUNCHED BEAMS  

SciTech Connect

A new approach to solving the kinetic equation for the beam distribution function, (very useful from the practical point of view), is discussed, in which the authors also obtain a complement to the Skrinsky's condition for the self-focused bunched beam. This problem belongs to the theory of nonlinear systems in which both regular and chaotic motion is possible. The kinetic approach, based on Vlasov-Poisson equations, are used to investigate the focusing and acceleration of bunched beam. Special attention is given to the studies of stability in a bunched beam by means of the two norm, which may be used to describe t!he motion of high-energy particles.

PARSA,Z.; ZADOROZHNY,V.

2000-04-07

90

Laser and Particle Guiding Micro-Elements for Particle Accelerators  

SciTech Connect

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

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

2005-06-07

91

Multiple Application Intense Particle Beam Project  

NASA Astrophysics Data System (ADS)

The Multiple Application Intense Particle Beam project is an experiment in which an injector of high energy neutral or ionized particles will be used to diagnose high density and high temperature plasmas. The acceleration of the particles will be carried out feeding a diode with a high voltage pulse produced by a Marx generator. Other applications of intense particle beam generated by this injector that could be explored in the future include: heating and stabilization of compact toroids, treatment of metallic surfaces, and ion implantation.

Ueda, M.; Machida, M.

1988-06-01

92

A Vlasov solver for collective effects in particle accelerators  

Microsoft Academic Search

Integration techniques based on Lie algebraic methods have been successfully used in beam transport codes for particle accelerators. Generally these methods have been applied to problems of single-particle beam dynamics. Here we present an application of Lie algebraic techniques to the development of a Vlasov solver suitable for problems of beam transport in the presence of non-negligible particle self-fields. The

M. Migliorati; G. Dattoli; A. Schiavi; M. Venturini

2009-01-01

93

Acceleration of /sup 14/C beams in electrostatic accelerators  

SciTech Connect

Operational problems in the production and acceleration of /sup 14/C beams for nuclear structure research in Los Alamos National Laboratory's Van de Graaff accelerators are discussed. Methods for the control of contamination in ion sources, accelerators and personnel are described. Sputter source target fabrication techniques and the relative beam production efficiencies of various types of bound particulate carbon sputter source targets are presented.

Rowton, L.J.; Tesmer, J.R.

1981-01-01

94

Proceedings of the 2003 Particle Accelerator Conference  

SciTech Connect

The twentieth biennial Particle Accelerator Conference on Accelerator Science and Technology was held May 12 ? 16, 2003 at the Hilton Hotel in Portland, Oregon. The Stanford Linear Accelerator Center and the Lawrence Berkeley National Laboratory organized PAC 2003, and it was held under the auspices of the Nuclear and Plasma Sciences Society of the Institute of Electrical and Electronics Engineers and the Division of Physics of Beams of the American Physical Society. The attendance was 1025 registrants from 21 countries. The Program Committee was co-chaired by Alan Jackson and Ed Lee. The program they arranged had opening and closing plenary sessions that covered the most important accomplishments, opportunities, and applications of accelerators. During the remainder of the conference there were parallel sessions with oral and poster presentations. In addition, there was an industrial exhibit during the first three days. The Proceedings present a total of 1154 papers from the invited, contributed orals, and poster sessions.

various,

2004-03-01

95

Permanent-magnet material applications in particle accelerators  

SciTech Connect

The modern charged particle accelerator has found application in a wide range of scientific research, industrial, medical, and defense fields. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, which showed that magnetic field could be used to control the transverse envelope of charged particle beams. The history of permanent-magnet use in accelerator physics and technology is outlined, current design methods and material properties of concern for particle accelerator applications are reviewed.

Kraus, R.H. Jr.

1992-07-01

96

Permanent-magnet material applications in particle accelerators  

SciTech Connect

The modern charged particle accelerator has found application in a wide range of scientific research, industrial, medical, and defense fields. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, which showed that magnetic field could be used to control the transverse envelope of charged particle beams. The history of permanent-magnet use in accelerator physics and technology is outlined, current design methods and material properties of concern for particle accelerator applications are reviewed.

Kraus, R.H. Jr.

1992-01-01

97

Coulomb interactions in particle beams  

SciTech Connect

This book develops analytical and computer models for beams in which Coulomb interactions are important. The research into the different phenomena of Coulomb interactions in particle beams is stimulated by developments in the field of electron beam lithography for VLSI electronics. The standard theory of charged particle optics breaks down for intense beams in which interactions between particles are significant. This monograph is devoted to the theory of these intense beams, which are not only used in VLSI electronics but also in scanning electron microscopes. The theory is also applicable to focused ion beams, which are used in VLSI mask repair.

Jansen, G.H. (Royal Dutch Shell Lab., Amsterdam (NL))

1990-01-01

98

Nonparaxial Mathieu and Weber Accelerating Beams  

NASA Astrophysics Data System (ADS)

We demonstrate both theoretically and experimentally nonparaxial Mathieu and Weber accelerating beams, generalizing the concept of previously found accelerating beams. We show that such beams bend into large angles along circular, elliptical, or parabolic trajectories but still retain nondiffracting and self-healing capabilities. The circular nonparaxial accelerating beams can be considered as a special case of the Mathieu accelerating beams, while an Airy beam is only a special case of the Weber beams at the paraxial limit. Not only do generalized nonparaxial accelerating beams open up many possibilities of beam engineering for applications, but the fundamental concept developed here can be applied to other linear wave systems in nature, ranging from electromagnetic and elastic waves to matter waves.

Zhang, Peng; Hu, Yi; Li, Tongcang; Cannan, Drake; Yin, Xiaobo; Morandotti, Roberto; Chen, Zhigang; Zhang, Xiang

2012-11-01

99

Technique for fluence attenuation by acceleration of decay particles  

NASA Astrophysics Data System (ADS)

A nuclear beam of extremely low intensity was realized by accelerating decay particles from heavy radioactive nuclei through an AVF cyclotron. Alpha particles from a m241Am source (3.3 × 106 Bq) were accelerated up to 30 MeV with a cyclotron starting from a proper radius. The weak beam of alpha particles was detected and its energy and microscopic time structure was analyzed. The count rate was attenuated down to 5 counts per minute which is only 1/20 of the value estimated from source geometry and accelerator acceptance.

Itahashi, T.; Kondo, M.; Yamagata, T.

1996-06-01

100

Particle Acceleration in Relativistic Outflows  

NASA Astrophysics Data System (ADS)

In this review we confront the current theoretical understanding of particle acceleration at relativistic outflows with recent observational results on various source classes thought to involve such outflows, e.g. gamma-ray bursts, active galactic nuclei, and pulsar wind nebulae. We highlight the possible contributions of these sources to ultra-high-energy cosmic rays.

Bykov, Andrei; Gehrels, Neil; Krawczynski, Henric; Lemoine, Martin; Pelletier, Guy; Pohl, Martin

2012-11-01

101

A Fundamental Theorem on Particle Acceleration  

SciTech Connect

A fundamental theorem on particle acceleration is derived from the reciprocity principle of electromagnetism and a rigorous proof of the theorem is presented. The theorem establishes a relation between acceleration and radiation, which is particularly useful for insightful understanding of and practical calculation about the first order acceleration in which energy gain of the accelerated particle is linearly proportional to the accelerating field.

Xie, Ming

2003-05-01

102

Parallel simulation of beam-beam interaction in high energy accelerators  

SciTech Connect

In this paper, we present a self-consistent simulation model of beam-beam interaction in high energy accelerators. Using a parallel particle-in-cell approach, we have calculated the electromagnetic fields between two colliding beams. Dynamic load balance is implemented to improve the parallel efficiency. A preliminary performance test on IBM SP Power3, Cray T3E and PC cluster is presented. As an application, we studied the coherent beam-beam oscillation in the proposed Large Hadron Collider.

Qiang, Ji; Furman, Miguel A.; Ryne, Robert D.

2002-02-02

103

Particle acceleration by the sun  

SciTech Connect

Observations of hard X-ray/{gamma}-ray continuum and {gamma}-ray line emission show that electrons are accelerated to >{approx}100 s of MeV and ions up to GeV energies, respectively, in large solar flares. The flare-accelerated electrons above {approx}20 keV and ions above a few MeV often contain >{approx}10-50% or more of the total energy released, indicating that the particle acceleration is intimately related to the energy release mechanism. RHESSI observations show strong evidence that both the ion and electron acceleration are associated with the process of magnetic reconnection. Direct in situ observations of solar energetic particles (SEPs) near 1 AU indicate that shock waves driven by fast (>{approx}1000 km/s) coronal mass ejections (CMEs) accelerate ions and electrons to similarly high energies, at altitudes of {approx}2-40 solar radii. Both CMEs and large flares involve the transient release of up to {approx}10{sup 32}-10{sup 33} ergs. Frequent acceleration of electrons to {approx}10 keV is observed in smaller flares and even in microflares. Radio type III bursts indicate that electron acceleration can occur high in the corona, often without flare signatures at lower altitude. At 1 AU, hundreds of small impulsive SEP events are detected per year near solar maximum. These are dominated by <{approx}1 to {approx}100 keV electrons and often accompanied by tens of keV to MeV/nuc ions, strongly enriched in 3He and heavies. Here I review the recent RHESSI and related in situ observations as they bear on the fundamental acceleration processes that are occurring.

Lin, R. P. [Physics Department and Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States)

2008-08-25

104

Naked singularities as particle accelerators  

SciTech Connect

We investigate here the particle acceleration by naked singularities to arbitrarily high center of mass energies. Recently it has been suggested that black holes could be used as particle accelerators to probe the Planck scale physics. We show that the naked singularities serve the same purpose and probably would do better than their black hole counterparts. We focus on the scenario of a self-similar gravitational collapse starting from a regular initial data, leading to the formation of a globally naked singularity. It is seen that when particles moving along timelike geodesics interact and collide near the Cauchy horizon, the energy of collision in the center of mass frame will be arbitrarily high, thus offering a window to Planck scale physics.

Patil, Mandar; Joshi, Pankaj S. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

2010-11-15

105

Laser-and Beam-Driven Plasma Accelerators  

NASA Astrophysics Data System (ADS)

Scientists have been trying to use the tremendous electric fields in relativistic plasma waves to accelerate charged particles, and are now making substantial progress. If they succeed, future high energy accelerators will use plasma waves rather than microwave cavities as accelerating structures.Some accelerators, such as those used for radiation therapy will fit on a tabletop. Research on using plasma waves to accelerate particles began in earnest following the suggestion by John Dawson and his colleagues [1-3] that a relativistically propagating plasma wave or a wake field could be excited by using a powerful but short laser -or electron -beam as a driver pulse.Since their original suggestion the research on plasma --based accelerators has spread worldwide A series of experiments by the UCLA/USC/SLAC collaboration ,using the 30 GeV beam of the Stanford Linear Accelerator Center (SLAC), has demonstrated high-gradient acceleration of electrons and positrons using the the wake left by the SLAC beam as it passes through a lithium plasma. Electrons have been accelerated by more than 30 GeV in less than one meter. This acceleration gradient is about a thousand times larger than in conventional microwave-driven accelerators. It is a first step toward a ``plasma afterburner,'' which would be placed at the end of a kilometers-long conventional accelerator and double its beam energy in a few tens of meters. In addition to the acceleration of particle beams, these experiments have demonstrated the rich physics bounty to be reaped from relativistic beam-plasma interactions. This includes the generation of intense and narrowly collimated x-ray beams, refraction of particles at a plasma interface, and the creation of intense beams of positrons. These results are leading the way to similar tabletop accelerators based on plasma wakes excited by lasers rather than electron beams. Applications for tabletop accelerators include gamma radiography, radiation therapy, and ultra-fast materials science. [1] T.Tajima and J.M.Dawson Phys.Rev.Lett. 43,267.(1979) [2] P.Chen et.al. Phys.Rev.Lett.54,693,(1985) [3]C.Joshi et.al. Nature 311,525,(1984) In collaboration with all my past and present students and co-workers and in particular collaborators on E157,162,164 and 167 experiments at SLAC.

Joshi, Chandrashekhar

2006-10-01

106

Studies of beam dynamics in relativistic klystron two- beam accelerators  

NASA Astrophysics Data System (ADS)

Two-beam accelerators (TBAs) based upon free-electron lasers (FELs) or relativistic klystrons (RK-TBAs) have been proposed as efficient power sources for next generation high-energy linear colliders. Studies have demonstrated the possibility of building TBAs from X-band (~8-12 GHz) through Ka-band (~30-35 GHz) frequency regions. A new method of simulating the beam dynamics in accelerators of this type has been developed in this dissertation. There are three main components to this simulation. The first is a tracking algorithm to generate nonlinear transfer maps for pushing noninteracting particles through the external fields. A mapping algorithm is used so that tens or hundreds of thousands of macroparticles can be pushed from the solution of a few hundreds of differential equations. This is a great cost-savings device from the standpoint of CPU cycles. It can increase by several orders of magnitude the number of macroparticles that take place in the simulation, enabling more accurate modeling of the evolution of the beam distribution and enhanced sensitivity to effects due to the beam's halo. The second component is a 3D Particle-In-Cell (PIC) algorithm that solves a set of Helmholtz equations for the self-fields, including the conducting boundary condition, and generates impulses that are interleaved with the nonlinear maps by means of a split- operator algorithm. The Helmholtz equations are solved by a multi-grid algorithm. The third component is an equivalent circuit equation solver that advances the modal rf cavity fields in time due to excitation by the modulated beam. The beam-cavity interaction is analyzed and divided naturally into two distinct times scales. The RTA project is described, and the simulation code is used to design the latter portions of the experiment. Detailed calculations of the beam dynamics and of the rf cavity output are presented and discussed. A beamline design is presented that will generate nearly 1.2 TW of power from 40 input, gain, and output rf cavities over a 10 m distance. The simulations show that beam current losses are acceptable, and that longitudinal and transverse focusing techniques are sufficiently capable of maintaining a high degree of beam quality along the entire beamline. Additional experimental efforts are described. The first is the commissioning of the RTA injector. This electron gun produces a 1 MV, 600 A beam over a 250 ns pulse length. The post-injector beamline is described, and the battery of diagnostics is presented, with initial results reported. (Abstract shortened by UMI.)

Lidia, Steven Michael

107

PLASMA WAKE EXCITATION BY LASERS OR PARTICLE BEAMS  

SciTech Connect

Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. Plasma wake excitation driven by lasers or particle beams is examined, and the implications of the different physical excitation mechanisms for accelerator design are discussed. Plasma-based accelerators have attracted considerable attention owing to the ultrahigh field gradients sustainable in a plasma wave, enabling compact accelerators. These relativistic plasma waves are excited by displacing electrons in a neutral plasma. Two basic mechanisms for excitation of plasma waves are actively being researched: (i) excitation by the nonlinear ponderomotive force (radiation pressure) of an intense laser or (ii) excitation by the space-charge force of a dense charged particle beam. There has been significant recent experimental success using lasers and particle beam drivers for plasma acceleration. In particular, for laser-plasma accelerators (LPAs), the demonstration at LBNL in 2006 of high-quality, 1 GeV electron beams produced in approximately 3 cm plasma using a 40 TW laser. In 2007, for beam-driven plasma accelerators, or plasma-wakefield accelerators (PWFAs), the energy doubling over a meter to 42 GeV of a fraction of beam electrons on the tail of an electron beam by the plasma wave excited by the head was demonstrated at SLAC. These experimental successes have resulted in further interest in the development of plasma-based acceleration as a basis for a linear collider, and preliminary collider designs using laser drivers and beam drivers are being developed. The different physical mechanisms of plasma wave excitation, as well as the typical characteristics of the drivers, have implications for accelerator design. In the following, we identify the similarities and differences between wave excitation by lasers and particle beams. The field structure of the plasma wave driven by lasers or particle beams is discussed, as well as the regimes of operation (linear and nonlinear wave). Limitations owing to driver emittance are also discussed.

Schroeder, Carl B.; Esarey, Eric; Benedetti, Carlo; Toth, Csaba; Geddes, Cameron; Leemans, Wim

2011-04-01

108

Performance of magnetically-injected-plasma opening switches on the particle beam fusion accelerator II (PBFA II)  

Microsoft Academic Search

Summary form only given, as follows. Plasma opening switch (POS) experiments have been performed on the PBFA II 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 1×1012 to

G. E. Rochau; D. H. McDaniel; C. W. Jr. Mendel; M. A. Sweeney; W. B. S. Moore; G. R. Mowrer; D. M. Zagar

1990-01-01

109

Negative ion beam acceleration and transport experiments  

SciTech Connect

The design of a negative ion beam transport system is discussed. The ion source and accelerator have produced a 1-A, 8 keV beam of H ions with a pulse length of 30 seconds. The beam was additionally characterized as to electron content, uniformity along the slot, emittance perpendicular to the slot, and the beam divergence. 8 refs., 5 figs. (WRF)

Cooper, W.S.; Anderson, O.A.; Kwan, J.; Steele, W.F.

1985-11-01

110

Particle accelerators test cosmological theory  

SciTech Connect

Over the past decade two subfields of science, cosmology and elementary-particle physics, have become married in a symbiotic relationship that has produced a number of exciting offspring. These offspring are beginning to yield insights on the creation of spacetime and matter at epochs as early as 10 to the minus 43 to 10 to the minus 35 second after the birth of the universe in the primordial explosion known as the big bang. Important clues to the nature of the big bang itself may even come from a theory currently under development, known as the ultimate theory of everything (T.E.O.). A T.E.O. would describe all the interactions among the fundamental particles in a single bold stroke. Now that cosmology ahs begun to make predictions about elementary-particle physics, it has become conceivable that those cosmological predictions could be checked with carefully controlled accelerator experiments. It has taken more than 10 years for accelerators to reach the point where they can do the appropriate experiments, but the experiments are now in fact in progress. The preliminary results confirm the predictions of cosmology. The cosmological prediction the authors have been concerned with pertains to setting limits on the number of fundamental particles of matter. It appears that there are 12 fundamental particles, as well as their corresponding antiparticles. Six of the fundamental particles are quarks. The other six are leptons. The 12 particles are grouped in three families, each family consisting of four members. Cosmology suggests there must be a finite number of families and, further limits the possible range of to small values: only three or at most four families exist. 7 figs.

Schramm, D.N.; Steigman, G.

1988-06-01

111

Superconducting cavities for particle accelerators  

NASA Astrophysics Data System (ADS)

RF Superconductivity has become an important technology for particle accelerators for high energy physics, nuclear physics, and free electron lasers. More than 100 MVolts of Superconducting RF (SRF) cavities have been installed in accelerators for heavy ions and operated at gradients of 2-3 MV/m in excess of 105 hours. More than 500 MVolts are installed in electron accelerators and operated at gradients of 4-6 MV/m in excess of 104 hours. Encouraged by this success, another 500 meters of SRF cavities are in the production line. New applications for High Energy Physics are forthcoming for high current e+e- colliders in the B-quark energy range (B-factory). For the next linear collider in the TeV energy range, there are many compelling attractions to use SRF, if the gradients can be improved substantially and the costs lowered. Substantial progress has been made in understanding performance limitations and in inventing cures through better cavity geometries, materials, and processes. Techniques are now in hand to reach 15-20 MV/m accelerating. In light of this progress, the potential of high gradient SRF for a TeV Energy Superconducting Linear Accelerator (TESLA) will be explored.

Padamsee, H.

1992-02-01

112

Relativistic klystron two-beam accelerator  

SciTech Connect

Relativistic klystrons (RKs) are being developed as an RF power source for high gradient accelerator applications which include large linear electron-positron colliders, compact accelerators, and FEL sources. In a relativistic klystron two-beam accelerator (RK-TBA), the drive beam passes through a large number of RF output structures. High conversion efficiency of electron beam energy to RF energy is achieved in this concept by reacceleration of the modulated drive beam between output structures. The authors have conducted experiments studying the RF power extracted from various RK structures driven by modulated induction accelerator current pulses; the studies include work on improving the transport dynamics of the drive beam. They have started a demonstration in which the modulated induction beam current is reaccelerated by passage through subsequent induction accelerator cells.

Westenskow, G.A.; Houck, T.L. (Lawrence Livermore National Lab., CA (United States))

1994-10-01

113

New outlooks on bunched beam instabilities in particle accelerators. A proposal for a simple method to release a potential self-consistent high quality beam  

Microsoft Academic Search

Several hypotheses have been proposed to explain bunched beam instabilities under increasing intensity. In fact, the cause of these instabilities can be used to generate a very high quality beam. Total coherent synchrotron radiation brings the bunches to plasma density by self-consistent supercooling in the three bunch dimensions i.e. by reduction of energy dispersion. Maximal density and minimal residual instabilities

M. Bergher

1993-01-01

114

The cooling of particle beams  

SciTech Connect

A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling with beam coupling. Laser Cooling has provided beams of the lowest temperatures, namely 1 mK, but only for ions and only for the longitudinal temperature. Recent theoretical work has suggested how laser cooling, with the coupling of beam motion, can be used to reduce the ion beam temperature in all three directions. The majority of this paper is devoted to describing laser cooling and laser cooling with beam coupling.

Sessler, A.M.

1994-10-01

115

Resonance, particle dynamics, and particle transmission in the micro-accelerator platform  

NASA Astrophysics Data System (ADS)

We describe particle dynamics in the Micro-Accelerator Platform (MAP), a slab-symmetric dielectric laser accelerator (DLA), and model the expected performance of recently fabricated MAP structures. The quality of the structure resonances has been characterized optically, and results are compared with simulation. 3D trajectory analysis is used to model acceleration in those same structures ``as built.'' Results are applied to ongoing beam transmission and acceleration tests at NLCTA/E-163, in which transmission of 60 MeV injected electrons through the beam channel of the MAP was clearly observed, despite the overfilling of the structure by the beam.

McNeur, J.; Hazra, K. S.; Liu, G.; Sozer, E. B.; Travish, G.; Yoder, R. B.

2012-12-01

116

Fast ignition by a laser-accelerated deuteron beam  

NASA Astrophysics Data System (ADS)

Fast ignition (FI) of a conically guided DT assembly by a laser-accelerated deuteron beam is proposed. The uniformly pre-compressed fuel of 300 g cm-3 is heated by the deuteron beam of a Maxwellian energy distribution with a temperature of 3 MeV. This scheme makes full use of the deposited energy of the alpha particles produced by the athermal nuclear reactions and can save about 4.5% ion-beam energy compared with the FI by fast proton or carbon ion beams. The ignition energy delivered by the external beam can be reduced appreciably.

Liu, Dong-Xiao; Hong, Wei; Shan, Lian-Qiang; Wu, Shun-Chao; Gu, Yu-Qiu

2011-03-01

117

High Current batch Implanter Accelerator Column particle reduction  

Microsoft Academic Search

The fast scanning mechanism of High Current batch Implanter is achieved by spinning the wafer disk with angular speed more than 1200 Rotation-Per-Minute (RPM). If particles hit device wafers during implant it can cause serious damage to device structure. Particle generation areas are mainly from Source terminal, Accelerator Column, Plasma Flood Gun (PFG) and beam line wall. Preventive maintenance needs

Tiong Ung Chiong; Huang Cai Jun; Bustamyudin; Park Ju Young; Yong Ming; Loi Chee Meng; S. Loh; Zhiyong Zhao

2008-01-01

118

Particle Acceleration in Relativistic Shocks  

NASA Astrophysics Data System (ADS)

There is clear evidence from observations of x-ray and gamma ray radiation that electrons are accelerated to high velocities near energetic astrophysical objects such as pulsars, supernova remnants, and gamma-ray bursters. It is usually assumed that some or all of this acceleration takes place inside of relativistic shocks. We used 3D electromagnetic particle in cell codes to simulate generic relativistic shock formation conditions. We have simulated both electron-positron and electron-ion shock formation. In both cases two neutral plasma clouds collide at mildly relativistic velocities. This scenario is Weibel unstable. As the instability saturates, strong shear Alfven waves bounce around on a 'magnetic lattice' formed by the Weibel instability. These Alfven waves have large transverse electric fields associated with them E_t= fracVac ? B. We observe the part of the electron distribution resonant with these waves generate a high energy tail in the electron distribution. Work supported by NSF and DOE

Tonge, John; Fonseca, R. A.; Silva, L. O.; Dawson, J. D.; Mori, W. B.

2000-10-01

119

Particle beam fusion  

NASA Astrophysics Data System (ADS)

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/sq cm on PBFA-2 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-2 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-2 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.

Sweeney, M. A.

1994-08-01

120

Uniform Beam Distributions Of Charged Particle Beams  

SciTech Connect

The use of octupole elements was originally suggested [1] to transform the transverse Gaussian distribution of a charged particle beam into a uniform beam distribution having rectangular cross section. The first experimental realization of this concept was materialized at the Radiation Effects Facility (REF) of the Brookhaven National Laboratory (BNL)[2] where the transverse Gaussian distribution of a 200 MeV H{sup -} beam was transformed into a rectangular uniform distribution. Later, the beam line of the NASA Space Radiation Laboratory (NSRL) facility [3,4] built at BNL, was specifically designed to generate uniform beam distributions with rectangular cross sections, in both, the horizontal and vertical directions, at the location of the target. The NSRL facility generates uniform beam distributions of various nuclear species, which may vary in energy, and also vary in size of the uniform beam distribution. We will present an overview of the method to generate uniform beam distributions, show some results from the NSRL facility, and suggest other possibilities for generating such beam distributions.

Tsoupas, Nicholaos [CA, Brookhaven National Laboratory, 911B, Upton NY 11973 (United States)

2011-06-01

121

RFQ device for accelerating particles  

DOEpatents

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

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

1995-01-01

122

RFQ device for accelerating particles  

DOEpatents

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

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

1995-06-06

123

System of Pulsed Magnetic Commutation of a Beam in the I-2 Linear Accelerator.  

National Technical Information Service (NTIS)

A system is described of a pulse magnetic commutation of the I-2 linear accelerator beam. The system brings out the accelerated particles into three channels, respectively: to the proton synchrotron, to the analyzing magnet, to the experimentator equipmen...

A. M. Kozodaev N. V. Lazarev V. S. Skachkov S. V. Skachkov

1976-01-01

124

Shock effects in particle beam fusion targets  

NASA Astrophysics Data System (ADS)

At Sandia National Laboratorics we are assessing the response of fusion target materials to shock loading with the particle beam accelerators HYDRA and PROTO I and the gas gun facility. Nonlinear shock-accelerated unstable growth of fabriction irregularities has been demonstrated, and jetting is found to occur in imploding targets because of asymmetric beam deposition. Cylindrical ion targets display an instability due either to beam or target nonuniformity. However, the data suggest targets with aspect ratios of 30 may implode stably. The first time- and space-resolved measurements of shock-induced vaporization have been made. A homogeneous mixed phase EOS model cannot adequately explain the results because of the kinetic effects of vapor formation and expansion.

Sweeney, M. A.; Perry, F. C.; Asay, J. R.; Widner, M. M.

1982-04-01

125

Acceleration and stability of a high-current ion beam in induction fields  

NASA Astrophysics Data System (ADS)

A one-dimensional nonlinear analytic theory of the filamentation instability of a high-current ion beam is formulated. The results of 2.5-dimensional numerical particle-in-cell simulations of acceleration and stability of an annular compensated ion beam (CIB) in a linear induction particle accelerator are presented. It is shown that additional transverse injection of electron beams in magnetically insulated gaps (cusps) improves the quality of the ion-beam distribution function and provides uniform beam acceleration along the accelerator. The CIB filamentation instability in both the presence and the absence of an external magnetic field is considered.

Karas', V. I.; Manuilenko, O. V.; Tarakanov, V. P.; Federovskaya, O. V.

2013-03-01

126

Solitary waves in particle beams.  

National Technical Information Service (NTIS)

Since space charge waves on a particle beam exhibit both dispersive and nonlinear character, solitary waves or solitons are possible. Dispersive, nonlinear wave propagation in high current beams is found to be similar to ion-acoustic waves in plasmas with...

J. J. Bisognano

1996-01-01

127

Effects of Particle Beams in the Solar Atmosphere  

NASA Astrophysics Data System (ADS)

This work addresses the observational and physical effects of particle beams in the solar atmosphere. Mainly electron beams are considered. Describing acceleration mechanisms of superthermal particles, the main attention is devoted to effects influencing the particle beam propagation. The collisional energy losses and pitch angle scattering, the return current effects, and the mirroring in the converging magnetic field in specific situations are considered. Furthermore, the processes connected with the particle beam bombardment of dense layers of the solar atmosphere are briefly described. Finally, some open questions are summarized.

Karlicky, M.

128

Beam-beam interaction in P-P colliding accelerators  

SciTech Connect

One model for beam growth due to the beam-beam interaction in P-P colliding accelerators is that it is due to the presence of non-linear forces generated by the fields produced by the beam plus some radomizing effect like noise, or a tune modulation. According to this model, to limit beam-beam effects, one should try to limit the size of the non-linear forces and the sources of noise or tune modulation. This model can also be used to compare the severity of beam-beam effects in two situations by comparing the size of the non-linear forces. In this paper, this approach will be used to study three problems: to compare the effects of beam-beam non-linear resonances in the ISR with those in ISABELLE; to estimate the strength of a spectrometer magnet that may be placed at one of the beam crossing points, without appreciably increasing the beam-beam effects; and to compare the beam-beam interaction for colliding beam accelerators with different crossing-angles and different ..beta../sub x/ and ..beta../sub y/ at the crossing points.

Parzen, G.

1982-08-01

129

Beam generation, acceleration, and extraction on a stellatron accelerator  

SciTech Connect

The stellatron accelerator of the University of California at Irvine (UCI) [Phys. Fluids B [bold 2], 3149 (1990)] was modified to accommodate beam extraction. The magnetic field coils were reconstructed to adapt an extraction port. A fiberglass--graphite--epoxy chamber replaced the glass chamber that cracked frequently during the previous experiment. Improvement in the magnetic field configuration has significantly reduced the current loss during acceleration. A 1.1 kA, 12 MeV electron beam was generated by initially forming a 1.2 kA beam with plasma start-up. The beam radius was 5--7 mm. Beam extraction was performed with two auxiliary pulsed current coils and up to 15% of the beam was extracted from the chamber. The extraction process was analyzed by computational orbit simulations.

Song, Y.; Fisher, A.; Rostoker, N. (Department of Physics, University of California, Irvine, California 92717 (United States))

1994-08-01

130

Magnetic Control of Particle Injection in Plasma Based Accelerators  

NASA Astrophysics Data System (ADS)

The use of an external transverse magnetic field to trigger and to control electron self-injection in laser- and particle-beam driven wakefield accelerators is examined analytically and through full-scale particle-in-cell simulations. A magnetic field can relax the injection threshold and can be used to control main output beam features such as charge, energy, and transverse dynamics in the ion channel associated with the plasma blowout. It is shown that this mechanism could be studied using state-of-the-art magnetic fields in next generation plasma accelerator experiments.

Vieira, J.; Martins, S. F.; Pathak, V. B.; Fonseca, R. A.; Mori, W. B.; Silva, L. O.

2011-06-01

131

Magnetic control of particle injection in plasma based accelerators.  

PubMed

The use of an external transverse magnetic field to trigger and to control electron self-injection in laser- and particle-beam driven wakefield accelerators is examined analytically and through full-scale particle-in-cell simulations. A magnetic field can relax the injection threshold and can be used to control main output beam features such as charge, energy, and transverse dynamics in the ion channel associated with the plasma blowout. It is shown that this mechanism could be studied using state-of-the-art magnetic fields in next generation plasma accelerator experiments. PMID:21702605

Vieira, J; Martins, S F; Pathak, V B; Fonseca, R A; Mori, W B; Silva, L O

2011-05-31

132

Fundamentals of relativistic particle beam optics  

SciTech Connect

This lecture introduces the nonaccelerator-specialist to the motion of charged particles in a Storage Ring. The topics of discussion are restricted to the linear and nonlinear dynamics of a single particle in the transverse plane, i.e., the plane perpendicular to the direction of motion. The major omissions for a complete review of accelerator theory, for which a considerable literature exists, are the energy and phase oscillations (1). Other important accelerator physics aspects not treated here are the collective instabilities (2), the role of synchrotron radiation in electron storage rings (3), scattering processes (4), and beam-beam effects in colliding beam facilities (5). Much of the discussion that follows applies equally well to relativistic electron, proton, or ion synchrotrons. In this narrative, we refer to the particle as electron. After a broad overview, the magnetic forces acting on the electrons and the associated differential equations of motion are discussed. Solutions of the equations are given without derivation; the method of solution is outlined. and references for deeper studies are given. In this paper, the word electron is used to signify electron or positron. The dynamics of a single particle are not affected by the sign of its charge when the magnetic field direction is changed accordingly.

Cornacchia, M.

1995-12-01

133

The Los Alamos Laser Acceleration of Particles Workshop and beginning of the advanced accelerator concepts field  

NASA Astrophysics Data System (ADS)

The first Advanced Acceleration of Particles-AAC-Workshop (actually named Laser Acceleration of Particles Workshop) was held at Los Alamos in January 1982. The workshop lasted a week and divided all the acceleration techniques into four categories: near field, far field, media, and vacuum. Basic theorems of particle acceleration were postulated (later proven) and specific experiments based on the four categories were formulated. This landmark workshop led to the formation of the advanced accelerator R&D program in the HEP office of the DOE that supports advanced accelerator research to this day. Two major new user facilities at Argonne and Brookhaven and several more directed experimental efforts were built to explore the advanced particle acceleration schemes. It is not an exaggeration to say that the intellectual breadth and excitement provided by the many groups who entered this new field provided the needed vitality to then recently formed APS Division of Beams and the new online journal Physical Review Special Topics-Accelerators and Beams. On this 30th anniversary of the AAC Workshops, it is worthwhile to look back at the legacy of the first Workshop at Los Alamos and the fine groundwork it laid for the field of advanced accelerator concepts that continues to flourish to this day.

Joshi, C.

2012-12-01

134

An Undulator-Based Laser Wakefield Accelerator Electron Beam Diagnostic  

NASA Astrophysics Data System (ADS)

Currently particle accelerators such as the Large Hadron Collider use RF cavities with a maximum field gradient of 50-100 MV/m to accelerate particles over long distances. A new type of plasma based accelerator called a Laser Plasma Accelerator (LPA) is being investigated at the LOASIS group at Lawrence Berkeley National Laboratory which can sustain field gradients of 10-100 GV/m. This new type of accelerator offers the potential to create compact high energy accelerators and light sources. In order to investigate the feasibility of producing a compact light source an undulator-based electron beam diagnostic for use on the LOASIS LPA has been built and calibrated. This diagnostic relies on the principal that the spectral analysis of synchrotron radiation from an undulator can reveal properties of the electron beam such as emittance, energy and energy spread. The effects of electron beam energy spread upon the harmonics of undulator produced synchrotron radiation were derived from the equations of motion of the beam and numerically simulated. The diagnostic consists of quadrupole focusing magnets to collimate the electron beam, a 1.5 m long undulator to produce the synchrotron radiation, and a high resolution high gain XUV spectrometer to analyze the radiation. The undulator was aligned and tuned in order to maximize the flux of synchrotron radiation produced. The spectrometer was calibrated at the Advanced Light Source, with the results showing the ability to measure electron beam energy spreads at resolutions as low as 0.1% rms, a major improvement over conventional magnetic spectrometers. Numerical simulations show the ability to measure energy spreads on realistic LPA produced electron beams as well as the improvements in measurements made with the quadrupole magnets. Experimentally the quadrupoles were shown to stabilize and focus the electron beams at specific energies for their insertion into the undulator, with the eventual hope of producing an all optical Free Electron Laser operating in the XUV and soft x-ray regimes.

Bakeman, Michael S.

135

High Quality Electron Beams from Laser Accelerators  

NASA Astrophysics Data System (ADS)

Twenty five years ago, laser driven accelerators were proposed as an alternative to conventional accelerator systems.[1] The appeal was and is the large accelerating gradients (up to hundreds of GV/m) that can allow the development of compact devices capable of producing multi-GeV electron beams. Until recently, all experiments produced large gradients but beams with 100 % energy spread and only a small amount of electrons at high energy. This has recently changed. At the multi-beam L'OASIS facility at LBNL we have produced beams with narrow energy spread using a channel guided laser accelerator.[2] At Rutherford Appleton Laboratories (UK)[3] and at the Ecole Polytechnique (France),[4] beams with narrow energy spread were produced by using laser beams with relatively large focal spots. These results demonstrate that laser-plasma based accelerator can produce high quality electron beams. A review of the L'OASIS experiments will be presented as well as our plans and activities for producing a GeV-class electron beam. [1] T. Tajima and J.M. Dawson, Phys. Rev. Lett. 43, 267-270 (1979). [2] C.G.R. Geddes et al., Nature 431, 538- 541(2004). [3] S.P.D. Mangles et al., Nature 431, 535 --538 (2004). [4] J. Faure et al., Nature 431, 541-544 (2004).

Leemans, Wim

2005-04-01

136

Beam Coupling to Optical Scale Accelerating Structures  

SciTech Connect

Current research efforts into structure based laser acceleration of electrons utilize beams from standard RF linacs. These beams must be coupled into very small structures with transverse dimensions comparable to the laser wavelength. To obtain decent transmission, a permanent magnet quadrupole (PMQ) triplet with a focusing gradient of 560 T/m is used to focus into the structure. Also of interest is the induced wakefield from the structure, useful for diagnosing potential accelerator structures or as novel radiation sources.

Sears, C.M.; Byer, R.L.; Colby, E.R.; Cowan, B.M.; Ischebeck, R.; Lincoln, M.R.; Siemann, R.H.; Spencer, J.E.; /SLAC; Plettner, T.; /Stanford U., Phys. Dept.

2007-03-27

137

Stochastic Particle Acceleration by Helical Turbulence in Solar Flares  

NASA Astrophysics Data System (ADS)

Modern X-ray and radio observations favor a stochastic (Fermi) acceleration mechanism of fast particles produced in flares, which implies that an accelerating turbulence must somehow be generated by the primary flare energy release. The very release of free magnetic energy is only possible if the magnetic field deviates from a potential one. We show that this magnetic field nonpotentiality, via its corresponding current helicity, necessarily results in a noticeable kinetic helicity of the turbulence generated at the flare site by the primary energy release. We study the role of the turbulence helicity on the particle acceleration and find that a nonzero turbulence helicity has a remarkably strong effect on the particle acceleration. The main reason for this strong helicity effect is that the helical component of the turbulence induces, through a well-known alpha-effect, a regular large-scale electric field capable of directly accelerating charged particles (like in the models with DC field acceleration). We estimate the turbulence kinetic helicity based on measured photospheric and extrapolated values of the current helicity and take into consideration the helical turbulence effect on stochastic particle acceleration. We find that this induced large-scale electric field can be comparable with the electron and estimated effective ion Dreicer fields, which has an immediate effect on charged particle extraction from the thermal pool and their injection into stochastic acceleration process. We have discovered that this, so far missing but highly important, ingredient of the particle stochastic acceleration by turbulence at the flare site is naturally consistent with such puzzling flare manifestations as spatial separation of electron and proton emission sites, electron beam formation, and enrichment of the accelerated particle population by 3He and other tiny ions. This work was supported in part by NSF grant AGS-0961867 and NASA grant NNX10AF27G to New Jersey Institute of Technology.

Fleishman, Gregory D.; Toptygin, I. N.

2012-05-01

138

The appreciation of stochastic motion in particle accelerators  

SciTech Connect

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

Symon, Keith; Sessler, Andrew

2003-08-03

139

Solitary waves in particle beams  

SciTech Connect

Since space charge waves on a particle beam exhibit both dispersive and nonlinear character, solitary waves or solitons are possible. Dispersive, nonlinear wave propagation in high current beams is found to be similar to ion-acoustic waves in plasmas with an analogy between Debye screening and beam pipe shielding. Exact longitudinal solitary wave propagation is found for potentials associated with certain transverse distributions which fill the beam pipe. For weak dispersion, the waves satisfy the Korteweg-deVries (KdV) equation, but for strong dispersion they exhibit breaking. More physically realizable distributions which do not fill the beam pipe are investigated and shown to also satisfy a KdV equation for weak dispersion if averaging over rapid transverse motion is physically justified. Scaling laws are presented to explore likely parameter regimes where these phenomena may be observed experimentally.

Bisognano, J.J. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

1996-07-01

140

Controlled Electron Acceleration in a Plane Laser Beam  

NASA Astrophysics Data System (ADS)

Through numerical modeling of the relativistic test particle motion of an ensemble of electrons in a plane laser beam, we show in the present contribution that a significant electron acceleration arises if an additional perpendicularly propagagating transverse laser beam with a randomized phase is present. We also demonstrate that the acceleration rate can be controlled by the power flux intensity of the additional laser beam. The power flux intensity of the additional beam can be typically much lower than the power flux intensity of the main laser beam. In the main laser beam, the electrons perform also a forward oscillating motion because of the effects of the magnetic field intensity of the beam. The acceleration results from the accumulation of the forward electron motion due to phase changes provided by the additional laser beam. For parameters of the PALS^1 device (Prague Asterix Laser System), the attainable electron energy is about 40 MeV in 10^4 wave periods. [2pt] Acknowledgments: This work has been supported by Czech grant GACR 202/00/1217 and USDOE Grant DE-FG02-97ER54398. [2pt] ^1K.Jungwirth et al., Phys. Plasmas 8 (2001) 2495.

Tataronis, J. A.; Petržílka, V.; Krlín, L.

2002-11-01

141

Plasma wakefield acceleration of an intense positron beam  

NASA Astrophysics Data System (ADS)

The Plasma Wakefield Accelerator (PWFA) is an advanced accelerator concept which possess a high acceleration gradient and a long interaction length for acceleratiog both electrons and positrons. Although electron beam-plasma interactions have been extensively studied in connection with the PWFA, very little work has been done with respect to positron beam-plasma interactions. This dissertation addresses three issues relating to a positron beam driven plasma wakefield accelerator. These issues are (a) the suitability of employing a positron drive bunch to excite a wake; (b) the transverse stability of the drive bunch; and (c) the acceleration of positrons by the plasma wake that is driven by a positron bunch. These three issues are explored first through computer simulations and then through experiments. First, a theory is developed on the impulse response of plasma to a short drive beam which is valid for small perturbations to the plasma density. This is followed up with several particle-in-cell (PIC) simulations which study the experimental parameter (bunch length, charge, radius, and plasma density) range. Next, the experimental setup is described with an emphasis on the equipment used to measure the longitudinal energy variations of the positron beam. Then, the transverse dynamics of a positron beam in a plasma are described. Special attention is given to the way focusing, defocusing, and a tilted beam would appear to be energy variations as viewed on our diagnostics. Finally, the energy dynamics imparted on a 730 mum long, 40 mum radius, 28.5 GeV positron beam with 1.2 x 1010 particles in a 1.4 meter long 0--2 x 1014 e-/cm3 plasma is described. First the energy loss was measured as a function of plasma density and the measurements are compared to theory. Then, an energy gain of 79 +/- 15 MeV is shown. This is the first demonstration of energy gain of a positron beam in a plasma and it is in good agreement with the predictions made by the 3-D PIC code. The work presented in this dissertation will show that plasma wakefield accelerators are an attractive technology for future particle accelerators.

Blue, Brent Edward

142

Laser-driven shock acceleration of monoenergetic ion beams.  

PubMed

We show that monoenergetic ion beams can be accelerated by moderate Mach number collisionless, electrostatic shocks propagating in a long scale-length exponentially decaying plasma profile. Strong plasma heating and density steepening produced by an intense laser pulse near the critical density can launch such shocks that propagate in the extended plasma at high velocities. The generation of a monoenergetic ion beam is possible due to the small and constant sheath electric field associated with the slowly decreasing density profile. The conditions for the acceleration of high-quality, energetic ion beams are identified through theory and multidimensional particle-in-cell simulations. The scaling of the ion energy with laser intensity shows that it is possible to generate ~200 MeV proton beams with state-of-the-art 100 TW class laser systems. PMID:23215596

Fiuza, F; Stockem, A; Boella, E; Fonseca, R A; Silva, L O; Haberberger, D; Tochitsky, S; Gong, C; Mori, W B; Joshi, C

2012-11-20

143

Laser-Driven Shock Acceleration of Monoenergetic Ion Beams  

NASA Astrophysics Data System (ADS)

We show that monoenergetic ion beams can be accelerated by moderate Mach number collisionless, electrostatic shocks propagating in a long scale-length exponentially decaying plasma profile. Strong plasma heating and density steepening produced by an intense laser pulse near the critical density can launch such shocks that propagate in the extended plasma at high velocities. The generation of a monoenergetic ion beam is possible due to the small and constant sheath electric field associated with the slowly decreasing density profile. The conditions for the acceleration of high-quality, energetic ion beams are identified through theory and multidimensional particle-in-cell simulations. The scaling of the ion energy with laser intensity shows that it is possible to generate ˜200MeV proton beams with state-of-the-art 100 TW class laser systems.

Fiuza, F.; Stockem, A.; Boella, E.; Fonseca, R. A.; Silva, L. O.; Haberberger, D.; Tochitsky, S.; Gong, C.; Mori, W. B.; Joshi, C.

2012-11-01

144

Particle acceleration at collisionless shocks: An overview  

SciTech Connect

An overview of shock acceleration is presented, focusing primarily on interplanetary shocks and the termination shock as examples. An extended discussion of recent advances in modeling real solar energetic particle (SEP) and energetic storm particle (ESP) events is presented. When the energy of accelerated particles becomes very large, their back reaction on the flow can result in a shock that is significantly mediated, and as an example, we consider some results for the termination shock.

Zank, G.P.; Li Gang; Webb, G.M.; Le Roux, J.A.; Florinski, V.; Ao, X.; Rice, W.K.M. [Institute of Geophysics and Planetary Physics, University of California, Riverside, CA 92521 (United States)

2005-08-01

145

Particle Accelerators Test Cosmological Theory.  

ERIC Educational Resources Information Center

|Discusses the symbiotic relationship of cosmology and elementary-particle physics. Presents a brief overview of particle physics. Explains how cosmological considerations set limits on the number of types of elementary particles. (RT)|

Schramm, David N.; Steigman, Gary

1988-01-01

146

Implications of accelerator experiments for models of the Kolar gold mine particles  

Microsoft Academic Search

The significance of accelerator searches for the new particles discovered in the Kolar Gold Mine experiments depends on the characteristics of the models of these particles. Models that could give cosmic ray neutrinos a great advantage over accelerator neutrinos are presented. The new particles should be produced in e+e- colliding beams, but the cross-section is model dependent.

K. V. L. Sarma; L. Wolfenstein

1976-01-01

147

Frequency multiplying oscillator with an electron beam accelerated in a drift space  

SciTech Connect

In a uniform acceleration region, the behavior of a velocity-modulated electron beam has been analyzed using a particle-in-cell code. By making use of one of the accelerated harmonic components of the velocity-modulated electron beam, we demonstrate a frequency multiplying oscillator for a compact THz emitter, which employs multiple electron beams and a higher order mode resonator to modulate the electron beam without an additional driving source.

Jang, Kyu-Ha; Lee, Kitae; Hee Park, Seong; Uk Jeong, Young [WCI Center for Quantum Beam-based Radiation Research, Korea Atomic Energy Research Institute, 1045 Deadeok, Yuseong, Daejeon 305-353 (Korea, Republic of); Miginsky, S. [WCI Center for Quantum Beam-based Radiation Research, Korea Atomic Energy Research Institute, 1045 Deadeok, Yuseong, Daejeon 305-353 (Korea, Republic of); Budker Institute of Nuclear Physics, SB RAS, Academician Lavrentyev St. 11, Novosibrisk (Russian Federation)

2012-07-02

148

A large distributed digital camera system for accelerator beam diagnostics  

SciTech Connect

Optical diagnostics, providing images of accelerated particle beams using radiation emitted by particles impinging a radiator, typically a fluorescent screen, has been extensively used, especially on electron linacs, since the 1970's. Higher intensity beams available in the last decade allow extending the use of beam imaging techniques to perform precise measurements of important beam parameters such as emittance, energy, and energy spread using optical transition radiation (OTR). OTR-based diagnostics systems are extensively used on the superconducting TESLA Test Facility (TTF) linac driving the vacuum ultraviolet free electron laser (VUV-FEL) at the Deutsches Elektronen-Synchrotron facility. Up to 30 optical diagnostic stations have been installed at various positions along the 250-m-long linac, each equipped with a high-performance digital camera. This paper describes the new approach to the design of the hardware and software setups required by the complex topology of such a distributed camera system.

Catani, L.; Cianchi, A.; Di Pirro, G.; Honkavaara, K. [Istituto Nazionale Fisica Nucleare (INFN)-Roma2, Via della Ricerca Scientifica 1, Rome (Italy); Istituto Nazionale Fisica Nucleare-Laboratori Nazionali di Frascati (INFN-LNF), Via Enrico Fermi 40, Frascati (Italy); Deutsches Elektronen-Synchrotron (DESY), 22 603 Hamburg (Germany)

2005-07-15

149

A large distributed digital camera system for accelerator beam diagnostics  

NASA Astrophysics Data System (ADS)

Optical diagnostics, providing images of accelerated particle beams using radiation emitted by particles impinging a radiator, typically a fluorescent screen, has been extensively used, especially on electron linacs, since the 1970's. Higher intensity beams available in the last decade allow extending the use of beam imaging techniques to perform precise measurements of important beam parameters such as emittance, energy, and energy spread using optical transition radiation (OTR). OTR-based diagnostics systems are extensively used on the superconducting TESLA Test Facility (TTF) linac driving the vacuum ultraviolet free electron laser (VUV-FEL) at the Deutsches Elektronen-Synchrotron facility. Up to 30 optical diagnostic stations have been installed at various positions along the 250-m-long linac, each equipped with a high-performance digital camera. This paper describes the new approach to the design of the hardware and software setups required by the complex topology of such a distributed camera system.

Catani, L.; Cianchi, A.; di Pirro, G.; Honkavaara, K.

2005-07-01

150

Charged Particle Acceleration by Lasers in Plasmas  

SciTech Connect

Several physical processes of laser electron acceleration in plasmas are revisited. A laser beam can drive plasma waves which in turn can accelerate resonant electrons. If these plasma waves can reach amplitude limited only by wave breaking alone, then the corresponding accelerating gradient in the plasma wave is of the order of electron rest mass energy per plasma skin depth, typically about GEV per centimeter. This is several orders of magnitudes higher than the conventional RF field gradient, giving rise to the possibility of compact accelerators needed for high energy physics research as well as medical and other applications. The chirped short pulse laser, with intensity exceeding the threshold for relativistic self focusing, can generate ion bubble in its wake by expelling electrons. The electrons at the bubble boundary, surge toward the stagnation point and pile up there. As the pile acquires a critical size, these electrons are injected into the bubble and accelerated by the combined fields of ion space charge and the plasma wave to Gev in energy. Most remarkably these electrons are bunched in phase space while being accelerated to high energy, resulting in near mono-energetic electron beam of high beam quality, with narrow energy spread. We review also other processes related to laser electron acceleration, such as acceleration in plasma wave assisted by ponderomotive force and betatron acceleration.

Liu, C. S.; Tripathi, V. K. [Department of Physics, University of Maryland, College Park, MD 20742 (United States)

2007-07-11

151

Charged Particle Acceleration by Lasers in Plasmas  

NASA Astrophysics Data System (ADS)

Several physical processes of laser electron acceleration in plasmas are revisited. A laser beam can drive plasma waves which in turn can accelerate resonant electrons. If these plasma waves can reach amplitude limited only by wave breaking alone, then the corresponding accelerating gradient in the plasma wave is of the order of electron rest mass energy per plasma skin depth, typically about GEV per centimeter. This is several orders of magnitudes higher than the conventional RF field gradient, giving rise to the possibility of compact accelerators needed for high energy physics research as well as medical and other applications. The chirped short pulse laser, with intensity exceeding the threshold for relativistic self focusing, can generate ion bubble in its wake by expelling electrons. The electrons at the bubble boundary, surge toward the stagnation point and pile up there. As the pile acquires a critical size, these electrons are injected into the bubble and accelerated by the combined fields of ion space charge and the plasma wave to Gev in energy. Most remarkably these electrons are bunched in phase space while being accelerated to high energy, resulting in near mono-energetic electron beam of high beam quality, with narrow energy spread. We review also other processes related to laser electron acceleration, such as acceleration in plasma wave assisted by ponderomotive force and betatron acceleration.

Liu, C. S.; Tripathi, V. K.

2007-07-01

152

Design and testing of a supercritical helium beamline cryopump for a neutral particle beam in space  

Microsoft Academic Search

As part of the BEAR Project (Beam Experiments Aboard a Rocket), being conducted by the Los Alamos National Laboratory and sponsored by the SDIO, the first ever flight qualified beamline cryopump for a neutral particle beam in space, has been designed, fabricated and tested. The BEAR payload consists primarily of a neutral particle beam accelerator whose injector produces a beam

J. Bascunan; J. F. Maguire

1990-01-01

153

Discrete beam acceleration in uniform waveguide arrays  

SciTech Connect

Within the framework of the tight-binding model we demonstrate that Wannier-Stark states can freely accelerate in uniform optical lattices. As opposed to accelerating Airy wave packets in free space, our analysis reveals that in this case the beam main intensity features self-bend along two opposite hyperbolic trajectories. Two-dimensional geometries are also considered and an asymptotic connection between these Wannier-Stark ladders and Airy profiles is presented.

El-Ganainy, Ramy [Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario, M5S 1A7 (Canada); Makris, Konstantinos G. [Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna (Austria); Miri, Mohammad Ali; Christodoulides, Demetrios N. [College of Optics-CREOL, University of Central Florida, Orlando, Florida 32816 (United States); Chen Zhigang [Department of Physics and Astronomy, San Francisco State University, San Francisco, California 94132 (United States)

2011-08-15

154

TRANSVERSE WAKEFIELD EFFECTS IN THE TWO-BEAM ACCELERATOR  

SciTech Connect

Transverse wakefield effects in the high-gradient accelerating structure of the Two-Beam Accelerator (TBA) [1-3] are analyzed theoretically using three different models. The first is a very simple two-particle model due to Wilson [4]; the second, due to Chao, Richter, and Yao [5], is for a beam with uniform charge distribution, constant betatron wavelength, and a linear wake approximation. Both of these models give analytic scaling laws. The third model has a Gaussian beam (represented by 11 superparticles), energy variation across the bunch, acceleration, variation of betatron focusing with energy, and variation of the wakefield from linearity. The three models are compared, and the third model is used to explore the wakefield effects when accelerator parameters such as energy, energy spread, injection energy, accelerating gradient, and betatron wavelength are varied. Also explored are the sensitivity of the beam to the wakefield profile and to the longitudinal charge distribution. Finally, in consideration of wakefield effects, possible parameters of a TBA are presented.

Selph, F.; Sessler, A.

1985-08-01

155

Study of space charge compensation phenomena in charged particle beams.  

PubMed

The propagation of a charged particle beam is accompanied by the production of secondary particles created in the interaction of the beam itself with the background gas flowing in the accelerator tube. In the drift region, where the electric field of the electrodes is negligible, secondary particles may accumulate giving a plasma which shields the self-induced potential of the charged beam. This phenomenon, known as space charge compensation is a typical issue in accelerator physics, where it is usually addressed by means of 1D radial transport codes or Monte Carlo codes. The present paper describes some theoretical studies on this phenomenon, presenting a Particle in Cell-Monte Carlo (PIC-MC) Code developed ad hoc where both radial and axial confinements of secondary particles are calculated. The features of the model, offering a new insight on the problem, are described and some results discussed. PMID:22380314

Veltri, P; Cavenago, M; Serianni, G

2012-02-01

156

Accelerators for heavy-charged-particle radiation therapy.  

PubMed

This paper focuses on current and future designs of medical hadron accelerators for treating cancers and other diseases. Presently, five vendors and several national laboratories have produced heavy-particle medical accelerators for accelerating nuclei from hydrogen (protons) up through carbon and oxygen. Particle energies are varied to control the beam penetration depth in the patient. As of the end of 2006, four hospitals and one clinic in the United States offer proton treatments; there are five more such facilities in Japan. In most cases, these facilities use accelerators designed explicitly for cancer treatments. The accelerator types are a combination of synchrotrons, cyclotrons, and linear accelerators; some carry advanced features such as respiration gating, intensity modulation, and rapid energy changes, which contribute to better dose conformity on the tumor when using heavy charged particles. Recent interest in carbon nuclei for cancer treatment has led some vendors to offer carbon-ion and proton capability in their accelerator systems, so that either ion can be used. These features are now being incorporated for medical accelerators in new facilities. PMID:17668952

Coutrakon, George B

2007-08-01

157

Laser particle acceleration: Pushing atoms with light  

NASA Astrophysics Data System (ADS)

Controlling the velocity of neutral particles is an experimental challenge, owing to their absence of charge. Scientists have now demonstrated a technique that can be used to accelerate neutral argon atoms by polarizing them in moving optical lattices.

Osterwalder, Andreas

2012-06-01

158

A technology platform for translational research on laser driven particle accelerators for radiotherapy  

NASA Astrophysics Data System (ADS)

It is widely accepted that proton or light ion beams may have a high potential for improving cancer cure by means of radiation therapy. However, at present the large dimensions of electromagnetic accelerators prevent particle therapy from being clinically introduced on a broad scale. Therefore, several technological approaches among them laser driven particle acceleration are under investigation. Parallel to the development of suitable high intensity lasers, research is necessary to transfer laser accelerated particle beams to radiotherapy, since the relevant parameters of laser driven particle beams dramatically differ from those of beams delivered by conventional accelerators: The duty cycle is low, whereas the number of particles and thus the dose rate per pulse are high. Laser accelerated particle beams show a broad energy spectrum and substantial intensity fluctuations from pulse to pulse. These properties may influence the biological efficiency and they require completely new techniques of beam delivery and quality assurance. For this translational research a new facility is currently constructed on the campus of the university hospital Dresden. It will be connected to the department of radiooncology and host a petawatt laser system delivering an experimental proton beam and a conventional therapeutic proton cyclotron. The cyclotron beam will be delivered on the one hand to an isocentric gantry for patient treatments and on the other hand to an experimental irradiation site. This way the conventional accelerator will deliver a reference beam for all steps of developing the laser based technology towards clinical applicability.

Enghardt, W.; Bussmann, M.; Cowan, T.; Fiedler, F.; Kaluza, M.; Pawelke, J.; Schramm, U.; Sauerbrey, R.; Tünnermann, A.; Baumann, M.

2011-05-01

159

US particle accelerators: an historical perspective  

SciTech Connect

The history of the development of particle accelerators, especially in the US, is reviewed. The development is traced from the earliest efforts of Cockroft and Walton through the early cyclotrons, e.g., that of E.O. Lawrence, to the modern high energy machines such as those at Fermilab and CERN. Linear accelerators and meson factories are also described. Sociological factors, funding and the role of national laboratories are discussed. The outlook for higher energy accelerators in the future is briefly considered.

Wilson, R.R.

1985-01-01

160

Single particle dynamics in circular accelerators  

SciTech Connect

The purpose of this paper is to introduce the reader to the theory associated with the transverse dynamics of single particle, in circular accelerators. The discussion begins with a review of Hamiltonian dynamics and canonical transformations. The case of a single particle in a circular accelerator is considered with a discussion of non-linear terms and chromaticity. The canonical perturbation theory is presented and nonlinear resonances are considered. Finally, the concept of renormalization and residue criterion are examined. (FI)

Ruth, R.D.

1986-10-01

161

On the use of the autocorrelation and covariance methods for feedforward control of transverse angle and position jitter in linear particle beam accelerators  

SciTech Connect

It is desired to design a predictive feedforward transverse jitter control system to control both angle and position jitter in pulsed linear accelerators. Such a system will increase the accuracy and bandwidth of correction over that of currently available feedback correction systems. Intrapulse correction is performed. An offline process actually {open_quotes}learns{close_quotes} the properties of the jitter, and uses these properties to apply correction to the beam. The correction weights calculated offline are downloaded to a real-time analog correction system between macropulses. Jitter data were taken at the Los Alamos National Laboratory (LANL) Ground Test Accelerator (GTA) telescope experiment at Argonne National Laboratory (ANL). The experiment consisted of the LANL telescope connected to the ANL ZGS proton source and linac. A simulation of the correction system using this data was shown to decrease the average rms jitter by a factor of two over that of a comparable standard feedback correction system. The system also improved the correction bandwidth.

Barr, D.S.

1993-11-01

162

Physical Review Special Topics : Accelerators and Beams  

NSDL National Science Digital Library

Current and past issues of this free American Physical Society peer-reviewed, electronic journal are available here. The journal is published on an article-by-article basis, and new articles are added to the latest issue. March titles in Physical Review Special Topics--Accelerators and Beams include "Coherent off-axis undulato radiation from short electron bunches."

163

Electron Beam Ion Sources for Accelerator Applications  

Microsoft Academic Search

Electron beam ion sources (EBIS) are capable of producing highly charged ions of any element which can be injected into its trap region. In addition to its use as a source for low energy atomic physics experiments, EBIS has been used to provide highly charged ions to accelerators and storage rings at Dubna, Saclay, and Stockholm. An EBIS is well

Edward N. Beebe

1996-01-01

164

Modeling of beam-ionized sources for plasma accelerators  

Microsoft Academic Search

When considering intense particle or laser beams propagating in dense plasma or gas, ionization plays an important role. Impact ionization and tunnel ionization may create new plasma electrons, altering the physics of wakefield accelerators, creating and modifying instabilities, etc. Here we describe the addition of an ionization package into the 3-D object-oriented fully parallel PIC code OSIRIS [R.G Hemker, F.S.

S. Deng; C. D. Barnes; C. E. Clayton; C. O'Connell; F. J. Decker; P. Emma; O. Erdem; C. Huang; M. J. Hogan; R. Iverson; D. K. Johnson; C. Joshi; T. Katsouleas; P. Krejcik; W. Lu; K. A. Marsh; W. B. Mori; P. Muggli; R. H. Siemann; D. Walz

2003-01-01

165

The United States Particle Accelerator School: Educating the Next Generation of Accelerator Scientists and Engineers  

NASA Astrophysics Data System (ADS)

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

Barletta, William A.

2009-03-01

166

Accelerating and storing polarized hadron beams  

SciTech Connect

Polarization hadron experiments at high energies continue to generate surprises. Many questions remain unanswered or unanswerable within the frame work of QCD. These include such basic questions as to why at high energies the polarization analyzing power in pp elastic scattering remains high, why hyperons are produced with high polarizations etc. It is, therefore, interesting to investigate the possibilities of accelerating and storing polarized beams in high energy colliders. On the technical side the recent understanding and confirmation of the actions of partial and multiple Siberian snakes made it possible to contemplate accelerating and storing polarized hadron beams to multi-TeV energies. In this paper, we will examine the equipment, the operation and the procedure required to obtain colliding beams of polarized protons at TeV energies.

Teng, L.C.

1990-10-01

167

Power converters for particle accelerators  

Microsoft Academic Search

In 1905 Albert Einstein wrote his legendary articles which provided the basis for three fundamental fields in physics: the theory of special relativity, quantum theory and the theory of Brownian motion. Subsequently, particle physics made dramatic progress in the understanding of the fundamental forces and particles, and underlying symmetries of nature. These achievements were based on intensive interaction between the

F. Bordry

2005-01-01

168

Shock effects in particle-beam fusion targets  

NASA Astrophysics Data System (ADS)

The response of fusion target materials to shock loading is assessed. The particle beam accelerators HYDRA and PROTO I and the gas gun facility were utilized. Nonlinear shock-accelerated unstable growth of fabrication irregularities were demonstrated, and jetting was found to occur in imploding targets because of asymmetric beam deposition. Cylindrical ion targets display an instability due either to beam or target nonuniformity. However, the data suggest targets with aspect ratios of 30 may implode stably. The first time- and space-resolved measurments of shock-induced vaporization were made. A homogeneous mixed phase EOS model cannot adequately explain the results because of the kinetic effects of vapor formation and expansion.

Sweeney, M. A.; Perry, F. C.; Asay, J. R.; Widner, M. M.

1981-06-01

169

Understanding particle acceleration at supernova shocks  

NASA Astrophysics Data System (ADS)

One century after the pioneering discovery of cosmic rays by V. Hess, the present generation of X- and gamma-ray telescopes is finally unravelling the origin of such an extraterrestrial radiation, at least for what concerns particles with energies below ˜10^8 GeV, which are thought to be accelerated at the forward shocks of Galactic supernova remnants (SNRs). I discuss the present theoretical understanding of efficient particle acceleration at non-relativistic, collisionless shocks, addressing with both analytical and numerical (particle-in-cell) techniques the crucial interplay between accelerated ions and magnetic turbulence. In SNRs, in fact, magnetic fields turn out to be a factor of 10-100 larger than in the interstellar medium, because of plasma instabilities triggered by energetic particles. In particular, I show 2D and 3D hybrid (fluid electrons - kinetic ions) simulations of non-relativistic collisionless shocks, pointing out the efficiency of Fermi acceleration and the role of the cosmic-ray-induced filamentation instability in amplifying the magnetic field up to the levels inferred at the blast waves of young Galactic remnants. Finally, I outline the observational counterparts of such a theory of particle acceleration at strong shocks in terms of SNR multi-wavelength emission, with a special attention to Tycho's SNR, arguably the best laboratory where to test hadron acceleration.

Caprioli, Damiano

2013-04-01

170

Phase Control of the Microwave Radiation in Free Electron Laser Two-Beam Accelerator.  

National Technical Information Service (NTIS)

A phase control system for the FEL portion of Two-Beam Accelerator is proposed. The control keeps the phase error within acceptable bounds. The control mechanism is analyzed, both analytically in a ''resonant particle'' approximation and numerically in a ...

Y. Goren A. M. Sessler

1987-01-01

171

Beam dynamics simulation of the Spallation Neutron Source linear accelerator  

SciTech Connect

The accelerating structure for Spallation Neutron Source (SNS) consists of a radio-frequency-quadrupole-linac (RFQ), a drift-tube-linac (DTL), a coupled-cavity-drift-tube-linac (CCDTL), and a coupled-cavity-linac (CCL). The linac is operated at room temperature. The authors discuss the detailed design of linac which accelerates an H{sup {minus}} pulsed beam coming out from RFQ at 2.5 MeV to 1000 MeV. They show a detailed transition from 402.5 MHz DTL with a 4 {beta}{lambda} structure to a CCDTL operated at 805 MHz with a 12 {beta}{lambda} structure. After a discussion of overall feature of the linac, they present an end-to-end particle simulation using the new version of the PARMILA code for a beam starting from the RFQ entrance through the rest of the linac. At 1000 MeV, the beam is transported to a storage ring. The storage ring requires a large ({+-}500-keV) energy spread. This is accomplished by operating the rf-phase in the last section of the linac so the particles are at the unstable fixed point of the separatrix. They present zero-current phase advance, beam size, and beam emittance along the entire linac.

Takeda, H.; Billen, J.H.; Bhatia, T.S.

1998-12-31

172

Statistical phenomena in particle beams  

SciTech Connect

Particle beams are subject to a variety of apparently distinct statistical phenomena such as intrabeam scattering, stochastic cooling, electron cooling, coherent instabilities, and radiofrequency noise diffusion. In fact, both the physics and mathematical description of these mechanisms are quite similar, with the notion of correlation as a powerful unifying principle. In this presentation we will attempt to provide both a physical and a mathematical basis for understanding the wide range of statistical phenomena that have been discussed. In the course of this study the tools of the trade will be introduced, e.g., the Vlasov and Fokker-Planck equations, noise theory, correlation functions, and beam transfer functions. Although a major concern will be to provide equations for analyzing machine design, the primary goal is to introduce a basic set of physical concepts having a very broad range of applicability.

Bisognano, J.J.

1984-09-01

173

``Accelerators and Beams,'' multimedia computer-based training in accelerator physics  

Microsoft Academic Search

We are developing a set of computer-based tutorials on accelerators and charged-particle beams under an SBIR grant from the DOE. These self-paced, interactive tutorials, available for Macintosh and Windows platforms, use multimedia techniques to enhance the user's rate of learning and length of retention of the material. They integrate interactive ``On-Screen Laboratories,'' hypertext, line drawings, photographs, two- and three-dimensional animations,

R. R. Silbar; A. A. Browman; W. C. Mead; R. A. Williams

1999-01-01

174

Accelerators and Beams,” multimedia computer-based training in accelerator physics  

Microsoft Academic Search

We are developing a set of computer-based tutorials on accelerators and charged-particle beams under an SBIR grant from the DOE. These self-paced, interactive tutorials, available for Macintosh and Windows platforms, use multimedia techniques to enhance the user’s rate of learning and length of retention of the material. They integrate interactive “On-Screen Laboratories,” hypertext, line drawings, photographs, two- and three-dimensional animations,

R. R. Silbar; A. A. Browman; W. C. Mead; R. A. Williams

1999-01-01

175

Production of an Accelerated Oxygen-14 Beam  

SciTech Connect

BEARS is an ongoing project to provide a light-ion radioactive-beam capability at the 88-Inch Cyclotron at LBNL. Light radioactive isotopes are produced at a 10 MeV proton medical cyclotron, transported 350 m via a high-speed gas transport capillary, cryogenically separated, and injected into the 88-Inch Cyclotron's ion source. The first radioactive beam successfully accelerated was Carbon-11 and beams of intensity more than 108 ions/sec have been utilized for experiments. Development of Oxygen-14 as the second BEARS beam presented considerable technical challenges, both due to its short half-life of 71 seconds and the radiation chemistry of oxygen in the target. The usual techniques developed for medical uses of Oxygen-15 involve the addition of significant amounts of carrier oxygen, something that would overload the ion source. As a solution, Oxygen-14 is produced as water in a carrier-free form, and is chemically converted in two steps to carbon dioxide, a form readily usable by the BEARS. This system has been built and is operational, and initial tests of accelerating an Oxygen-14 beam have been performed.

Powell, James; O'Neil, James P.; Cerny, Joseph

2002-05-03

176

Particle acceleration and energy conservation in particle in cell simulations  

Microsoft Academic Search

Particle acceleration is a process of great importance in all areas of plasma physics. In most cases, kinetic effects are dominant and require a full kinetic treatment, such as the particle in cell (PIC) method. PIC methods are widely used in all aspects of plasma physics, proving to be a precious and irreplaceable tool. Yet all methods in use and

Giovanni Lapenta; Stefano Markidis

2011-01-01

177

Neutral particle beams for space defense  

SciTech Connect

Neutral particle beam (NPB) weapons direct highly focused high energy streams of electrically neutral atomic particles traveling at nearly the speed of light, escaping deflection from the earth's magnetic field and acting on the subatomic structure of a target, destroying it from within. The beam's brief contact with a reentry vehicle produces a nuclear reaction in the latter that yields particle emissions; by detecting and identifying those particles, it becomes possible to effectively distinguish warheads from decoys. Attention is given to the NPB program roles to be played by the Beam Experiment Aboard Rocket and Neutral Particle Beam Integrated Space Experiment projects.

Botwin, R.; Favale, A.

1987-01-01

178

GeV electron beams from a centimetre-scale accelerator  

Microsoft Academic Search

Gigaelectron volt (GeV) electron accelerators are essential to synchrotron radiation facilities and free-electron lasers, and as modules for high-energy particle physics. Radiofrequency-based accelerators are limited to relatively low accelerating fields (10-50MVm-1), requiring tens to hundreds of metres to reach the multi-GeV beam energies needed to drive radiation sources, and many kilometres to generate particle energies of interest to high-energy physics.

W. P. Leemans; B. Nagler; A. J. Gonsalves; Cs. Tóth; K. Nakamura; C. G. R. Geddes; E. Esarey; C. B. Schroeder; S. M. Hooker

2006-01-01

179

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

SciTech Connect

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)

Not Available

1981-01-01

180

Particle Acceleration at High-? Shock Waves  

NASA Astrophysics Data System (ADS)

First-order Fermi acceleration processes at ultrarelativistic (? ~ 5-30) shocks are studied with the method of Monte Carlo simulations. The accelerated particle spectra are obtained by integrating the exact particle trajectories in a turbulent magnetic field near the shock. The magnetic field model assumes finite-amplitude perturbations within a wide wavevector range and with a predefined wave power spectrum, which are imposed on the mean field component inclined at some angle to the shock normal. The downstream field structure is obtained as the compressed upstream field. We show that the main acceleration process at oblique shocks is the particle compression at the shock. Formation of energetic spectral tails is possible in a limited energy range for highly perturbed magnetic fields. Cut-offs in the spectra occur at low energies in the resonance range considered. We relate this feature to the structure of the magnetic field downstream of the shock, where field compression produces effectively 2D turbulence in which cross-field diffusion is very small. Because of the field compression downstream, the acceleration process is inefficient also in parallel high-? shocks for larger turbulence amplitudes, and features observed in oblique shocks are recovered. For small-amplitude perturbations, particle spectra are formed in a wide energy range and modifications of the acceleration process due to the existence of long-wave perturbations are observed. The critical turbulence amplitude for efficient acceleration at parallel shocks decreases with ?. We also study the influence of strong short-wave perturbations, generated downstream of the shock, on the particle acceleration processes at high-? shocks. The spectral indices obtained do not converge to the ``universal'' value ? ~ 4.2. Our results indicate inefficiency of the first-order Fermi process to generate high-energy cosmic rays at ultrarelativistic shocks with the perturbed magnetic field structures considered in the present work.

Niemiec, Jacek

2005-11-01

181

Particle acceleration at relativistic shock waves  

NASA Astrophysics Data System (ADS)

Relativistic sources, e.g. gamma-ray bursts, pulsar wind nebulae and powerful active galactic nuclei produce relativistic outflows that lead to the formation of collisionless shock waves, where particle acceleration is thought to take place. Our understanding of relativistic shock acceleration has improved in the past decade, thanks to the combination of analytical studies and high level numerical simulations. In ultra-relativistic shocks, particle acceleration is made difficult by the generically transverse magnetic field and large advection speed of the shocked plasma. Fast growing microturbulence is thus needed to make the Fermi process operative. It is thought, and numerical simulations support that view, that the penetration of supra-thermal particles in the shock precursor generates a magnetic turbulence which in turn produces the scattering process needed for particle acceleration through the Fermi mechanism. Through the comparison of the growth timescale of the microinstabilities in the shock precursor and the precursor crossing timescale, it is possible to delimit in terms of magnetization and shock Lorentz factor the region in which micro-turbulence may be excited, hence whether and how Fermi acceleration is triggered. These findings are summarized here and astrophysical consequences are drawn.

Lemoine, Martin; Pelletier, Guy

2012-04-01

182

The development of laser- and beam-driven plasma accelerators as an experimental field  

NASA Astrophysics Data System (ADS)

Since its inception in the early 1980s, the field of plasma-based particle accelerators has made remarkable advances. Robust plasma accelerating structures can now be excited over centimeter scales using short laser pulses and over meter scales using ultrarelativistic particle beams. Accelerating fields in excess of tens of GV/m can be sustained over these lengths. Laser-driven plasma accelerators now routinely produce monoenergetic, low divergence electron beams in the 100 MeV-1 GeV range, whereas electron-beam driven plasma accelerators have demonstrated the ability to double the energy of 42 GeV electrons using a high-energy collider beam in less than one meter. The development of this field is traced through a series of path breaking experiments.

Joshi, C.

2007-05-01

183

Beam collimation and transport of quasineutral laser-accelerated protons by a solenoid field  

Microsoft Academic Search

This article reports about controlling laser-accelerated proton beams with respect to beam divergence and energy. The particles are captured by a pulsed high field solenoid with a magnetic field strength of 8.6 T directly behind a flat target foil that is irradiated by a high intensity laser pulse. Proton beams with energies around 2.3 MeV and particle numbers of 1012

K. Harres; I. Alber; A. Tauschwitz; V. Bagnoud; H. Daido; M. Günther; F. Nürnberg; A. Otten; M. Schollmeier; J. Schütrumpf; M. Tampo; M. Roth

2010-01-01

184

Acceleration and Propagation of Solar Flare Energetic Particles.  

National Technical Information Service (NTIS)

Observations and theories of particle acceleration in solar flares are reviewed. The most direct signatures of particle acceleration in flares are gamma rays, X-rays and radio emissions produced by the energetic particles in the solar atmosphere and energ...

M. A. Forman R. Ramaty E. G. Zweibel T. E. Holzer D. Mihalas

1982-01-01

185

Isochoric heating with laser-accelerated proton beams  

NASA Astrophysics Data System (ADS)

Numerical simulations are used to study acceleration of protons by intense laser pulses and the induced heating of a secondary target using this proton beam. Laser-plasma interaction and ion acceleration are modeled with a multidimensional, relativistic particle-in-cell code. Proton slowing-down and secondary target heating are computed with a two-dimensional Monte Carlo and a one-dimensional Lagrangian hydrodynamics codes. Strategies for optimization of heating uniformity include tailoring the accelerated proton spectrum with specific target geometries or laser pulse parameters. A trade-off must then be found between heating uniformity and efficiency. The parameters (temperature, depth and radius of heated zone, characteristic heating and hydrodynamics times) that could be obtained on current short pulse laser facilities, using a typical 50 fs Gaussian pulse with an intensity of several 1019 W/cm2, are explored.

Carrié, M.; Combis, P.; Lefebvre, E.

2010-12-01

186

Accelerating parallel particle swarm optimization via GPU  

Microsoft Academic Search

Particle swarm optimization (PSO) is a population-based stochastic and derivative-free method that has been used to solve various optimization problems due to its simplicity and efficiency. While solving high-dimensional or complicated problems, PSO requires a large number of particles to explore the problem domains and consequently introduces high computational costs. In this paper, we focus on the acceleration of PSO

Yukai Hung; Weichung Wang

2010-01-01

187

Nonlinear Delta-f Particle Simulations of Collective Effects in High Intensity Charged Particle Beams  

NASA Astrophysics Data System (ADS)

A wide range of collective effects in high intensity charged particle beams have been numerically studied using the nonlinear delta-f particle simulation method implemented in the Beam Equilibrium Stability and Transport (BEST) code. For the electron-ion two-stream instability in high intensity accelerators and storage rings, the secondary electron yield effects are self-consistently studied by coupling the secondary electron yield library CMEE with the instability simulations. Progress has also been made in applying the delta-f particle simulation method to bunched beams, and a three-dimensional equilibrium solver has been implemented. With the help of recently developed parallel diagnostic techniques, we are able to characterize the chaotic particle dynamics under the influences of collective instabilities as well as three-dimensional equilibrium fields. To further extend the application areas of the delta-f particle simulation method, 2D domain decomposition is being developed using the Message Passing Interface, and three-dimensional equilibria with anisotropic temperature in the transverse and longitudinal directions are being investigated. References: [1] R. C. Davidson and H. Qin, An Introduction to the Physics of Intense Charged Particle Beams in High Energy Accelerators, World Scientific (2001). [2] H. Qin, Physics of Plasmas 10, 2078 (2003). [3] H. Qin, E. A. Startsev, and R. C. Davidson, Physical Review Special Topics on Accelerators and Beams 6, 014401 (2003).

Qin, Hong; Davidson, Ronald C.; Startsev, Edward A.

2004-11-01

188

Non-accelerator particle physics  

SciTech Connect

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

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

1991-09-01

189

Transverse instabilities in a relativistic klystron two-beam accelerator  

SciTech Connect

Transverse beam instabilities have been observed in the traveling-wave output structures of high-power microwave generators driven by induction accelerators. The relativistic klystron two-beam accelerator concept involves the transport of kiloamperes of current through many microwave output sections. Energy in both the cumulative and regenerative beam breakup modes could grow in these two-beam accelerator systems to levels that beam loss would occur. For induction accelerators the current term can be several orders of magnitude larger than values common for rf accelerators, presenting a difficult challenge for beam stability. In this paper we present experimental evidence of beam breakup in the output section of a high-power microwave generator, methods used to suppress the higher order modes in the power extraction sections, and computer modeling for transverse instabilities in larger relativistic klystron two-beam accelerator systems.

Westenskow, G.A.; Houck, T.L. (Lawrence Livermore National Lab., CA (United States)); Yu, S.S. (Lawrence Berkeley Lab., CA (United States))

1992-08-01

190

Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators  

SciTech Connect

The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC. Simulations studies and measurements were conducted that clearly show the correlation between RF noise and longitudinal bunch emittance, identify the major LLRF noise contributions, and determine the RF component dominating this effect. With these results, LHC upgrades and alternative algorithms are evaluated to reduce longitudinal emittance growth during operations. The applications of this work are described with regard to future machines and analysis of new technical implementations, as well as to possible future work which would continue the directions of this dissertation.

Mastoridis, Themistoklis; /Stanford U., Elect. Eng. Dept. /SLAC

2011-03-01

191

Plasma Astrophysics in the Laboratory with Accelerator Beams  

NASA Astrophysics Data System (ADS)

An ultra-relativistic electron/positron or ``fireball'' beam interacting with a laboratory plasma is subject to the current filamentation instability (CFI). In the near future, ultra-short (<100fs), ultra-relativistic (25GeV) electron and positron bunches will become available at the SLAC FACET facility. These bunches are accelerated one half period apart and overlapped in space and time near the final focal point. With an equal number of particles, these two bunches form a neutral, field- and charge-free beam that we call a relativistic fireball beam. The interaction of this beam with laboratory plasma is rather different from that of either the electron or positron bunch alone. No large wakefields are generated. Instead the beam is subject to the CFI, which results in transverse filamentation, accompanied by strong plasma density modulation, generation of large magnetic fields, and generation of radiation that can be detected. This situation is similar to that of space relativistic plasmas, e.g. from supernovae, interacting with the interstellar medium. The CFI generates the magnetic field, and the charged particles emit radiation as in gamma ray bursts afterglow. Detecting the CFI and measuring it characteristics will validate astrophysical models. CFI may also play an important role in the propagation of hot electrons in plasmas for example in the fast igniter concept of ICF. We describe the CFI and the experiment to detect it.

Muggli, P.; Martins, S.; Silva, L.

2010-11-01

192

Stochastic particle acceleration by helical turbulence in solar flares  

NASA Astrophysics Data System (ADS)

Flaring release of magnetic energy in solar corona is only possible if the magnetic field deviates from a potential one. We show that the linear magnetohydrodynamic (MHD) modes excited on top of the non-potential magnetic field possess a non-zero kinetic helicity. Accordingly, this necessarily results in a noticeable kinetic helicity of the turbulence, composed of these linear modes with various scales and random phases, generated at the flare site by the primary energy release, which may be important for many applications. In particular, a non-zero turbulence helicity has a potentially strong effect on the particle acceleration because the helical component of the turbulence induces a mean regular large-scale (DC) electric field capable of directly accelerating the charged particles in addition to the commonly considered stochastic turbulent electric field. In this paper, we derive the kinetic helicity density of the linear MHD modes excited on top of a twisted large-scale magnetic field, estimate the corresponding turbulence helicity and take its effect on stochastic particle acceleration by the turbulence into consideration; in particular, we compare this induced mean electric field with the electron and estimated effective ion Dreicer fields. We have discovered that this, so far missing but highly important, ingredient of the turbulence at the flare site can be responsible for the thermal-to-non-thermal energy partition in flares by controlling the process of particle extraction from the thermal pool and formation of the seed particle population to be then stochastically accelerated to higher energies. In addition, it is naturally consistent with such puzzling flare manifestations as spatial separation of electron and proton emission sites, electron beam formation, and enrichment of the accelerated particle population by 3He and other rare ions.

Fleishman, Gregory D.; Toptygin, Igor N.

2013-03-01

193

Particle acceleration and energy conservation in particle in cell simulations  

SciTech Connect

Particle acceleration is a process of great importance in all areas of plasma physics. In most cases, kinetic effects are dominant and require a full kinetic treatment, such as the particle in cell (PIC) method. PIC methods are widely used in all aspects of plasma physics, proving to be a precious and irreplaceable tool. Yet all methods in use and published conserve energy to a good approximation, but not exactly. A well known property of PIC methods, documented extensively in all textbooks, is that energy is not conserved exactly. In fact, the particle noise is a unphysical source of energy that, when insufficient resolution is used, can make the simulations go unstable. In the present paper, we apply a new exactly energy conserving scheme and demonstrate that indeed exact energy conservation plays a key role in determining the correct spectrum of the accelerated particles.

Lapenta, Giovanni; Markidis, Stefano [Centrum voor Plasma-Astrofysica, Departement Wiskunde, Katholieke Universiteit Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium)

2011-07-15

194

Particle acceleration and energy conservation in particle in cell simulations  

NASA Astrophysics Data System (ADS)

Particle acceleration is a process of great importance in all areas of plasma physics. In most cases, kinetic effects are dominant and require a full kinetic treatment, such as the particle in cell (PIC) method. PIC methods are widely used in all aspects of plasma physics, proving to be a precious and irreplaceable tool. Yet all methods in use and published conserve energy to a good approximation, but not exactly. A well known property of PIC methods, documented extensively in all textbooks, is that energy is not conserved exactly. In fact, the particle noise is a unphysical source of energy that, when insufficient resolution is used, can make the simulations go unstable. In the present paper, we apply a new exactly energy conserving scheme and demonstrate that indeed exact energy conservation plays a key role in determining the correct spectrum of the accelerated particles.

Lapenta, Giovanni; Markidis, Stefano

2011-07-01

195

Particle Acceleration and Energy Conservation in Particle In Cell Simulations  

NASA Astrophysics Data System (ADS)

Particle acceleration is a process of great importance in all areas of plasma physics. In most cases, kinetic effects are dominant and require a full kinetic treatment, such as the Particle in Cell (PIC) method. PIC methods are widely used in all aspects of plasma physics, proving to be a precious and irreplaceable tool. Yet all methods in use and published conserve energy to a good approximation, but not exactly. A well known property of PIC methods, documented extensively in all textbooks, is that energy is not conserved exactly. In fact the particle noise is a unphysical source of energy that, when insufficient resolution is used, can make the simulations go unstable. In the present paper we apply a new exactly energy conserving scheme and demonstrate that indeed exact energy conservation plays a key role in determining the correct spectrum of the accelerated particles.

Lapenta, Giovanni; Markidis, Stefano

2011-11-01

196

Challenges in Accelerating and Colliding Polarized Beams (455th Brookhaven Lecture)  

ScienceCinema

At the Relativistic Heavy Ion Collider (RHIC), scientists are investigating not only the primordial properties of the universe but also another fundamental question of particle physics: the property of "spin." A particle's spin comes from its intrinsic angular momentum and is a basic property such as charge or mass. Many existing and future high energy and nuclear physics experiments rely on accessing spin. These experiments require using beams of polarized particles, which have their spins all pointing in one direction. When used as a probe of matter, beams of polarized particles reveal details of fundamental interactions not accessible with unpolarized particles. Experiments using polarized beams also need accelerators capable of accelerating and colliding such beams while preserving polarization. Achieving this, as in so many extraordinary feats that make science discoveries possible, is easier said than done.

197

Challenges in Accelerating and Colliding Polarized Beams (455th Brookhaven Lecture)  

SciTech Connect

At the Relativistic Heavy Ion Collider (RHIC), scientists are investigating not only the primordial properties of the universe but also another fundamental question of particle physics: the property of "spin." A particle's spin comes from its intrinsic angular momentum and is a basic property such as charge or mass. Many existing and future high energy and nuclear physics experiments rely on accessing spin. These experiments require using beams of polarized particles, which have their spins all pointing in one direction. When used as a probe of matter, beams of polarized particles reveal details of fundamental interactions not accessible with unpolarized particles. Experiments using polarized beams also need accelerators capable of accelerating and colliding such beams while preserving polarization. Achieving this, as in so many extraordinary feats that make science discoveries possible, is easier said than done.

Ptitsyn, Vadim (Ph.D., Collider-Accelerator Department)

2010-02-17

198

Particle accelerators unravel Art and Archaeology issues  

Microsoft Academic Search

Many analytical techniques are applied to get a better insight on art works and archaeological artefacts and to contribute to their conservation and restoration. Because of the precious and sometimes unique character of these items, non-destructive and non-sampling techniques are preferred. From this standpoint, the analysis with ion beams produced by accelerators (IBA), featuring good analytical performance and non-destructiveness, constitutes

Thomas Calligaro

2008-01-01

199

Beam physics developments for a rare isotope accelerator  

Microsoft Academic Search

In support of a proposal for a Rare Isotope Accelerator facility, this thesis provides a preliminary analysis of a number of related subsystems. An overview of the requirements for the driver accelerator, production stations, and beam purification systems is presented. Some minor developments in the theory of beam transport and acceleration are presented in order to discuss a technique for

Mauricio Portillo

2002-01-01

200

High-gradient two-beam accelerator structure  

Microsoft Academic Search

A novel cavity structure is described that could be the basis for a two-beam, high-gradient, accelerator. Versions of the structure could be used for acceleration of beams of electrons, positrons, muons, protons, or heavier ions; with either electron or proton drive beams. The structure embodies cavities that are excited in several harmonically related eigenmodes, such that rf fields reach their

S. Yu Kazakov; S. V. Kuzikov; Y. Jiang; J. L. Hirshfield

2010-01-01

201

Particle Accelerators for Radiotherapy:. Present Status and Future  

NASA Astrophysics Data System (ADS)

The paper describes the development of the application of particle accelerators in the treatment of cancer diseases over the past fifty years. Special emphasis is put on the routine application of conventional electron accelerators delivering electron and photon beams. This is the largest group of devices for radiotherapy (over 7500 machines operating worldwide). The number of patients reaches 5 million per year. The medical electron linacs have recently undergone considerable modifications of construction, in particular the systems of radiation field shaping. Contemporary accelerators for radiotherapy are equipped with multi-leaf collimators (MLC) which, in conjunction with IMRT (Intensity Modulation Radiation Therapy) technique and special system of therapy planning, assure considerably higher precision, effectiveness and quality of treatment.

Maciszewski, Wieslaw; Scharf, Waldemar

2004-07-01

202

Interaction Between a High-Current Beam and an Accelerating System in Synchrotrons. Survey.  

National Technical Information Service (NTIS)

Review of the problem concerning the interaction between a high-current beam and an accelerating system in synchrotrons is presented. The beam models used have been discussed, in particular, the model of point particles, the model of the charged fluid and...

D. K. Dinev

1980-01-01

203

3-D Simulations of Plasma Wakefield Acceleration with Non-Idealized Plasmas and Beams.  

National Technical Information Service (NTIS)

3-D Particle-in-cell OSIRIS simulations of the current E-162 Plasma Wakefield Accelerator Experiment are presented in which a number of non-ideal conditions are modeled simultaneously. These include tilts on the beam in both planes, asymmetric beam emitta...

S. Deng T. Katsouleas S. Lee P. Muggli W. B. Mori

2002-01-01

204

``Accelerators and Beams,'' multimedia computer-based training in accelerator physics  

NASA Astrophysics Data System (ADS)

We are developing a set of computer-based tutorials on accelerators and charged-particle beams under an SBIR grant from the DOE. These self-paced, interactive tutorials, available for Macintosh and Windows platforms, use multimedia techniques to enhance the user's rate of learning and length of retention of the material. They integrate interactive ``On-Screen Laboratories,'' hypertext, line drawings, photographs, two- and three-dimensional animations, video, and sound. They target a broad audience, from undergraduates or technicians to professionals. Presently, three modules have been published (Vectors, Forces, and Motion), a fourth (Dipole Magnets) has been submitted for review, and three more exist in prototype form (Quadrupoles, Matrix Transport, and Properties of Charged-Particle Beams). Participants in the poster session will have the opportunity to try out these modules on a laptop computer.

Silbar, R. R.; Browman, A. A.; Mead, W. C.; Williams, R. A.

1999-06-01

205

Transient particle acceleration associated with solar flares.  

PubMed

Understanding how individual charged particles can be accelerated to extreme energies (10(20) electron volts), remains a foremost problem in astrophysics. Within our solar system, the active sun is capable of producing, on a short time scale, ions with energies higher than 25 gigaelectron volts. Satellite and ground-based observation over the past 30 years have greatly increased our knowledge of the properties of transient bursts of energetic particles emitted from the sun in association with solar flares, but a real understanding of the solar flare particle acceleration process requires greatly refined experimental data. On the practical side, it is also imperative that this problem be solved if man is to venture, for long periods of time, beyond the protective umbrella of Earth's magnetic field, which excludes much of the biologically damaging solar energetic particles. It is only through an understanding of the basic acceleration problem that we can expect to be able to predict the occurrence of a solar flare with lethal solar radiations. For our knowledge of these effects to advance, a new space mission dedicated to studying the high-energy aspects of solar flares at high spatial and energy resolution will be required. PMID:17797307

Chupp, E L

1990-10-12

206

Electrostatic plasma lens for focusing negatively charged particle beams  

NASA Astrophysics Data System (ADS)

We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

Goncharov, A. A.; Dobrovolskiy, A. M.; Dunets, S. M.; Litovko, I. V.; Gushenets, V. I.; Oks, E. M.

2012-02-01

207

Proceedings of the 1997 Particle Accelerator Conference Held in Vancouver, B.C., Canada on 12-16 May 1997. Volume 2: Beam Dynamics, Instrumentation and Controls.  

National Technical Information Service (NTIS)

The Proceedings contains 1261 papers presented at PAC'97, held in Vancouver in May, 1997. With one third of the 1221 delegates coming from 23 countries outside North America, these papers present a comprehensive picture of accelerator science, technology ...

J. Thomson M. Comyn M. Reiser M. K. Craddock

1997-01-01

208

Use of the autocorrelation and covariance methods for feedforward control of transverse angle and position jitter in linear particle beam accelerators.  

National Technical Information Service (NTIS)

It is desired to design a predictive feedforward transverse jitter control system to control both angle and position jitter in pulsed linear accelerators. Such a system will increase the accuracy and bandwidth of correction over that of currently availabl...

D. S. Barr

1993-01-01

209

Charged-particle beam: a safety mandate  

SciTech Connect

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.

Young, K.C.

1983-07-15

210

Naked singularities as particle accelerators. II.  

NASA Astrophysics Data System (ADS)

We generalize here our earlier results on particle acceleration by naked singularities. We showed recently [M. Patil and P. S. Joshi, Phys. Rev. DPRVDAQ1550-7998 82, 104049 (2010).10.1103/PhysRevD.82.104049] that the naked singularities that form due to the gravitational collapse of massive stars provide a suitable environment where particles could get accelerated and collide at arbitrarily high center-of-mass energies. However, we focused there only on the spherically symmetric gravitational collapse models, which were also assumed to be self-similar. In this paper, we broaden and generalize the result to all gravitational collapse models leading to the formation of a naked singularity as the final state of collapse, evolving from a regular initial data, without making any prior restrictive assumptions about the spacetime symmetries such as above. We show that, when the particles interact and collide near the Cauchy horizon, the energy of collision in the center-of-mass frame will be arbitrarily high, thus offering a window to the Planck scale physics. We also consider the issue of various possible physical mechanisms of generation of such very high-energy particles from the vicinity of naked singularity. We then construct a model of gravitational collapse to a timelike naked singularity to demonstrate the working of these ideas, where the pressure is allowed to be negative, but the energy conditions are respected. We show that a finite amount of mass-energy density has to be necessarily radiated away from the vicinity of the naked singularity as the collapse evolves. Therefore, the nature of naked singularities, both at the classical and quantum level, could play an important role in the process of particle acceleration, explaining the occurrence of highly energetic outgoing particles in the vicinity of the Cauchy horizon that participate in extreme high-energy collisions.

Patil, Mandar; Joshi, Pankaj S.; Malafarina, Daniele

2011-03-01

211

Naked singularities as particle accelerators. II  

SciTech Connect

We generalize here our earlier results on particle acceleration by naked singularities. We showed recently [M. Patil and P. S. Joshi, Phys. Rev. D 82, 104049 (2010).] that the naked singularities that form due to the gravitational collapse of massive stars provide a suitable environment where particles could get accelerated and collide at arbitrarily high center-of-mass energies. However, we focused there only on the spherically symmetric gravitational collapse models, which were also assumed to be self-similar. In this paper, we broaden and generalize the result to all gravitational collapse models leading to the formation of a naked singularity as the final state of collapse, evolving from a regular initial data, without making any prior restrictive assumptions about the spacetime symmetries such as above. We show that, when the particles interact and collide near the Cauchy horizon, the energy of collision in the center-of-mass frame will be arbitrarily high, thus offering a window to the Planck scale physics. We also consider the issue of various possible physical mechanisms of generation of such very high-energy particles from the vicinity of naked singularity. We then construct a model of gravitational collapse to a timelike naked singularity to demonstrate the working of these ideas, where the pressure is allowed to be negative, but the energy conditions are respected. We show that a finite amount of mass-energy density has to be necessarily radiated away from the vicinity of the naked singularity as the collapse evolves. Therefore, the nature of naked singularities, both at the classical and quantum level, could play an important role in the process of particle acceleration, explaining the occurrence of highly energetic outgoing particles in the vicinity of the Cauchy horizon that participate in extreme high-energy collisions.

Patil, Mandar; Joshi, Pankaj S.; Malafarina, Daniele [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

2011-03-15

212

A double-foil target for improving beam quality in laser ion acceleration with thin foils  

SciTech Connect

A double-foil target is proposed for laser ion acceleration with thin targets to take advantage of high efficiency of such targets while avoiding beam degradation in late stage of acceleration. Laser heating of electrons co-moving with the ion beam is stopped by the second foil. It is found that the second foil can also modify and substantially improve the spectral and spatial properties of the ion beam and reduce the temperature of the co-moving electrons, leading to better preservation of the beam quality. Details of the dynamics are studied with particle-in-cell simulations.

Huang, C.-K.; Albright, B. J.; Yin, L.; Wu, H.-C.; Bowers, K. J.; Hegelich, B. M.; Fernandez, J. C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2011-05-15

213

Proceedings of: 2005 Particle Acceleration Confence  

SciTech Connect

The 21st Particle Accelerator Conference, PAC05, took place at the Knoxville Convention Center (KCC) from Monday through Friday, May 16-20, 2005. Sponsored by the American Physical Society (APS), the Institute of Electrics and Electronics Engineers (IEEE) with its subdivision of Nuclear and Plasma Sciences Society (NPSS), the conference was hosted by the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source (SNS) Project and Thomas Jefferson National Accelerator Facility (JLab). The conference was chaired by Norbert Holtkamp, and the Local Organizing Committee was made up of staff from the ORNL SNS Project under the chairmanship of Stuart Henderson. The conference welcomed over 1400 delegates from the United States, Europe, Asia, the Middle East, South America and from as far away as Australia. Almost 1400 papers where processed during the conference and will be published on the Joint Accelerator Conferences Website (JACoW) page.

Henderson, Stuart

2006-01-01

214

Investigation of Electron Beam Behavior in a Linear Induction Accelerator.  

National Technical Information Service (NTIS)

A method for more accurate consideration of characteristics of electron beam with finite emittance for calculating the acceleration process in a linear induction accelerator is proposed. It includes the division of the whole phase space when the surface o...

L. A. Merkulov

1985-01-01

215

FASTBUS for the particle accelerator laboratories  

SciTech Connect

The FASTBUS modular high speed data acquisition and control system for high energy physics and other applications was described by Costrell and Dawson at the 1983 Particle Accelerator Conference. Both the specification and the implementation of this interlaboratory development have progressed considerably since that time. Because of its many attractive features, FASTBUS is currently in use in several major nuclear and high energy physics laboratories and is also finding application in other areas. 10 refs.

Dawson, W.K.; Costrell, L.; Ikeda, H.; Ponting, P.J.; Walz, H.V.

1985-05-01

216

Phase control of the microwave radiation in free electron laser two-beam accelerator  

SciTech Connect

A phase control system for the FEL portion of Two-Beam Accelerator is proposed. The control keeps the phase error within acceptable bounds. The control mechanism is analyzed, both analytically in a ''resonant particle'' approximation and numerically in a multi-particle simulation code. Sensitivity of phase errors to the FEL parameters has been noticed.

Goren, Y.; Sessler, A.M.

1987-07-01

217

High-gradient two-beam accelerator structure  

NASA Astrophysics Data System (ADS)

A novel cavity structure is described that could be the basis for a two-beam, high-gradient, accelerator. Versions of the structure could be used for acceleration of beams of electrons, positrons, muons, protons, or heavier ions; with either electron or proton drive beams. The structure embodies cavities that are excited in several harmonically related eigenmodes, such that rf fields reach their peak values only during small portions of each basic rf period. This feature could help raise breakdown and pulse heating thresholds. The two-beam accelerator structure comprises chains of these cavities. In this configuration, no transfer elements are needed to couple rf energy from the drive beam to the accelerated beam, since both beams traverse the same cavities. Purposeful cavity detuning is used to provide much smaller deceleration for a high-current drive beam, than acceleration for a low-current accelerated beam, i.e., to provide a high transformer ratio. A self-consistent theory is presented to calculate idealized acceleration gradient, transformer ratio, and efficiency for energy transfer from the drive beam to the accelerated beam, for either parallel or antiparallel motion of the beams. The theory has been cast in dimensionless quantities so as to facilitate optimization with respect to efficiency, acceleration gradient, or transformer ratio, and to illuminate the interdependence of these parameters. Means for dramatically shortening the structure fill time are also described. However, no beam dynamics analysis is presented, so the range of parameters within which this new acceleration concept can be used will remain uncertain until it is established that stable beam transport along the structure using an appropriate focusing system is possible.

Kazakov, S. Yu; Kuzikov, S. V.; Jiang, Y.; Hirshfield, J. L.

2010-07-01

218

Novel accelerators employing high-current electron beams numerical simulations  

SciTech Connect

Numerical simulations codes are described which can be used to study the physical phenomena of high-current electron beams employed in some novel accelerator schemes. Examples are given of the study of transverse effects in the free electron laser part of a Two-Beam Accelerator, the study of ion guiding in a Relativistic Klystron, and a study of the acceleration phase of a Collective implosion Accelerator.

Fawley, W.M.; Teague, M.R.; Caporaso, G.J.; Yu, S.S.; Sessler, A.M.

1986-01-01

219

Cryogenic Pump with a Long Continuous Run Without Filling Intended for a Particle Accelerator.  

National Technical Information Service (NTIS)

A cryogenic pump is described, specially designed to be used in an electrostatic particle accelerator. The same tubular liquid helium bath provides pumping in the accelerating tube and around the beam. The temperature of the bath can be adjusted between 2...

F. Bottiglioni J. Coutant M. Fois R. Duthil J. C. Gelebart

1977-01-01

220

Educating the next generation in the science and technology of plasmas, beams and accelerators  

Microsoft Academic Search

Accelerators are essential tools for discovery in fundamental physics, biology, and chemistry. Particle beam based instruments in medicine, industry and national security constitute a multi-billion dollar per year industry. More than 55,000 peer-reviewed papers having accelerator as a keyword are available on the Web. Yet only a handful of universities offer any formal training in accelerator science. Several reasons can

Wiliam Barletta

2007-01-01

221

Channeled particle acceleration by plasma waves in metals  

SciTech Connect

A solid state accelerator concept utilizing particle acceleration along crystal channels by longitudinal electron plasma waves in a metal is presented. Acceleration gradients of order 100 GV/cm are theoretically possible. Particle dechanneling due to electron multiple scattering can be eliminated with a sufficiently high acceleration gradient. Plasma wave dissipation and generation in metals are also discussed.

Chen, P.; Noble, R.J.

1987-01-01

222

8.4 High Precision Power Converters for Particle Accelerators  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the the Section '8.4 High Precision Power Converters for Particle Accelerators' of the Chapter '8 Accelerator Technology' with the content:

Bordry, F.; Burnet, J. P.; Bastos, M. Cerqueira

223

Cooling of accelerator beams to improve focal properties  

Microsoft Academic Search

For inertial fusion with a heavy ion beam, several storage and buncher rings will be used to accumulate a high-current beam and produce a bunch shape as narrow as ~50 ns. The beams extracted from these rings will be transported to the target and used for the implosion of fuels. The key issues among the many accelerator beam dynamics problems

T. Katayama

1989-01-01

224

Radiation Safety System for SPIDER Neutral Beam Accelerator  

NASA Astrophysics Data System (ADS)

SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

Sandri, S.; Coniglio, A.; D'Arienzo, M.; Poggi, C.

2011-12-01

225

Radiation Safety System for SPIDER Neutral Beam Accelerator  

SciTech Connect

SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

Sandri, S.; Poggi, C. [ENEA, Radiation Protection Institute, IRP-FUAC, Frascati (Italy); Coniglio, A. [Medical Physics Department, S. Giovanni Calibita Hospital, Fatebenefratelli, Isola Tiberina, Roma (Italy); D'Arienzo, M. [ENEA, Ionizing Radiation Metrology National Institute, METR, Casaccia, Rome (Italy)

2011-12-13

226

Laser ion acceleration toward future ion beam cancer therapy - Numerical simulation study -  

PubMed Central

Background: Ion beam has been used in cancer treatment, and has a unique preferable feature to deposit its main energy inside a human body so that cancer cell could be killed by the ion beam. However, conventional ion accelerator tends to be huge in its size and its cost. In this paper a future intense-laser ion accelerator is proposed to make the ion accelerator compact. Subjects and methods: An intense femtosecond pulsed laser was employed to accelerate ions. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching and the ion particle energy control. In the study particle computer simulations were performed to solve the issues, and each component was designed to control the ion beam quality. Results: When an intense laser illuminates a target, electrons in the target are accelerated and leave from the target; temporarily a strong electric field is formed between the high-energy electrons and the target ions, and the target ions are accelerated. The energy efficiency from the laser to ions was improved by using a solid target with a fine sub-wavelength structure or by a near-critical density gas plasma. The ion beam collimation was realized by holes behind the solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching were successfully realized by a multi-stage laser-target interaction. Conclusions: The present study proposed a novel concept for a future compact laser ion accelerator, based on each component study required to control the ion beam quality and parameters.

Kawata, Shigeo; Izumiyama, Takeshi; Nagashima, Toshihiro; Takano, Masahiro; Barada, Daisuke; Kong, Qing; Gu, Yan Jun; Wang, Ping Xiao; Ma, Yan Yun; Wang, Wei Min

2013-01-01

227

Particle Acceleration at a Converging Shock Pair  

NASA Astrophysics Data System (ADS)

It has been recently suggested that a "twin-CME" scenario may be the cause of GLE events.[1] In some extreme events, such as the 2005.01.17 event, two fast shocks occur within 30 minutes and the second one catches the first. Here we examine particle acceleration at a converging shock pair using test particle simulation. Particle trajectories are followed with constant shock compression ratio and static upstream and downstream magnetic field. Both parallel and perpendicular diffusions are considered. With perp diffusion treated as gyro-centers jumping across field lines and parallel diffusion treated as gyro-centers "random walking" along the filed lines. Particle spectra upstream the first shock, downstream the first shock and downstream the second shock are obtained. The implication of a two-shock pair in enhancing the diffusive shock acceleration process will be discussed. [1] A twin-CME scenario for Ground Level Events, G. Li, R. Moore, R. A. Mewaldt, L. Zhao and A. Labrador, Space Science Review, to appear.

Zhao, L.; Li, G.

2011-12-01

228

Beam energy scaling of a stably operated laser wakefield accelerator  

SciTech Connect

Two-dimensional particle-in-cell simulations were performed to demonstrate the fluctuation of the maximum beam energy while varying the plasma density in a laser wakefield accelerator (LWFA) under the transition from mildly relativistic regime to relativistic regime. The fluctuation of the beam energy is induced by the unstable accelerating structure, which length is dynamically oscillating between the plasma wavelength and the relativistic plasma wavelength. The simulation results also reveal the existence of the parameter space for the stable operation of a LWFA. An empirical formulation was derived by the curve fitting of the simulated radius of curvature of the returning electrons along the boundary of the plasma bubble in a stably operated LWFA. The comparisons between the energy scaling law derived from the empirical formulation, the two-dimensional and three-dimensional PIC simulations, and previous experimental results with self-guided laser pulses show good agreement. The scaling law derived in the study can provide a correct estimation of the maximum beam energy for a newly designed LWFA experiment with an optimal configuration of the laser pulse.

Chen, S. H.; Lin-Liu, Y. R. [Department of Physics, National Central University, Jhongli 32001, Taiwan (China); Tai, L. C. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liu, C. S. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

2010-06-15

229

Laser steering of particle beams: refraction and reflection of particle beams  

NASA Astrophysics Data System (ADS)

The co-propagation of an intense particle beam with an ionizing laser beam in a working gas//plasma is considered. When the axes of the laser and particle beam are not aligned, then asymmetric plasma lensing results in a net dipole field acting on the particle beam. The particle beam can be steered or bent (as well as focused) by steering the laser. An analogy is made between the bending of the particle beam by collective effects at a plasma boundary and the refraction or reflection of light at an interface. This mechanism of particle steering may be of interest in applications for which permanent magnets are inconvenient or a fast turn on is required. 3-D particle-in-cell simulations and relevance to a recent experiment are discussed.

Katsouleas, T.; Mori, W. B.; Dodd, E.; Lee, S.; Hemker, R.; Clayton, C.; Joshi, C.; Esarey, E.

2000-11-01

230

Generating Particle Beams of Controlled Dimensions and Divergence: II. Experimental Evaluation of Particle Motion in Aerodynamic Lenses and Nozzle Expansions  

Microsoft Academic Search

A particle-beam-forming apparatus for producing narrow particle beams was developed based on the theory discussed in paper I of this series. It consists of a variable number of aerodynamic lenses (short capillaries and\\/or thin-plate orifices with diameters ranging from 3.5 to 7.0 mm) followed by an accelerating nozzle (3 mm). It was evaluated using monodisperse DOS and NaCl particles (0.02–0.24

Peng Liu; Paul J. Ziemann; David B. Kittelson; Peter H. McMurry

1995-01-01

231

High-energy accelerator for beams of heavy ions  

DOEpatents

An apparatus for accelerating heavy ions to high energies and directing the accelerated ions at a target comprises a source of singly ionized heavy ions of an element or compound of greater than 100 atomic mass units, means for accelerating the heavy ions, a storage ring for accumulating the accelerated heavy ions and switching means for switching the heavy ions from the storage ring to strike a target substantially simultaneously from a plurality of directions. In a particular embodiment the heavy ion that is accelerated is singly ionized hydrogen iodide. After acceleration, if the beam is of molecular ions, the ions are dissociated to leave an accelerated singly ionized atomic ion in a beam. Extraction of the beam may be accomplished by stripping all the electrons from the atomic ion to switch the beam from the storage ring by bending it in magnetic field of the storage ring.

Martin, Ronald L. (La Grange, IL); Arnold, Richard C. (Chicago, IL)

1978-01-01

232

Study of Extreme Ultraviolet Laser Sources for the Guiding of Particle Beams.  

National Technical Information Service (NTIS)

Spectrally bright femtosecond sources of short wavelength radiation can be applied to guide particle beams and possibly enable the collective acceleration of electrons. An effort directed at the development of extremely high peak power ultraviolet sources...

C. K. Rhodes

1987-01-01

233

Emittance in particle and radiation beam techniques  

SciTech Connect

The author discusses the important and diverse role of the phase space area - the emittance - in the advanced techniques involving interaction of particle and radiation beams. For undulator radiation from unbunched beams, the radiation phase space is diluted from the coherent phase space of the single electron radiation. When the undulator radiation is used as a light source, it is important to minimize the dilution by decreasing the beam emittance and matching the phase space distributions of the particle and the radiation beams. For optical stochastic cooling, on the other hand, the phase space should be maximally mismatched for efficient cooling. In the case particles are bunched to a length much shorter than the radiation wavelength, the emittance appears as an intensity enhancement factor. In the operation of free electron lasers, the phase space matching becomes doubly important, once as the dilution factor in the initial stage of energy modulation and then as the radiation efficiency factor at the end where the beam is density modulated. The author then discusses some of the beam cooling techniques producing smaller emittances, especially the recent suggestions for relativistic heavy ions in storage rings or electron beams in linacs. These are based on the radiative cooling that occurs when particle beams backscatter powerful laser beams.

Kim, Kwang-Je

1997-03-01

234

Neutral particle beam sensing and steering  

DOEpatents

The direction of a neutral particle beam (NPB) is determined by detecting Ly{alpha} radiation emitted during motional quenching of excited H(25) atoms in the beam during movement of the atoms through a magnetic field. At least one detector is placed adjacent the beam exit to define an optical axis that intercepts the beam at a viewing angle to include a volume generating a selected number of photons for detection. The detection system includes a lens having an area that is small relative to the NPB area and a pixel array located in the focal plane of the lens. The lens viewing angle and area pixel array are selected to optimize the beam tilt sensitivity. In one embodiment, two detectors are placed coplanar with the beam axis to generate a difference signal that is insensitive to beam variations other than beam tilt.

Maier, W.B. II; Cobb, D.D.; Robiscoe, R.T.

1990-08-30

235

Neutral particle beam discrimination and lethality  

SciTech Connect

Using, or possibly just developing, neutral particle beams (NPBs) to both discriminate decoys and kill weapons could induce 10-fold reductions in each. The conventional factor of two'' increase in the time required to do both does not capture particle beams' impact. They could reduce the threat to {approx}1 reentry vehicle (RV) plus {approx}10 decoys per heavy missile, which could be defeated at a 10-100:1 cost effectiveness ratio by current interceptors. 8 refs., 2 figs.

Canavan, G.H.; Browne, J.C.

1991-03-01

236

Beam collimation and transport of laser-accelerated protons by a solenoid field  

NASA Astrophysics Data System (ADS)

A pulsed high field solenoid was used in a laser-proton acceleration experiment to collimate and transport the proton beam that was generated at the irradiation of a flat foil by a high intensity laser pulse. 1012 particles at an energy of 2.3 MeV could be caught and transported over a distance of more than 240 mm. Strong space charge effects occur, induced by the high field of the solenoid that forces all co-moving electrons down the the solenoid's axis, building up a strong negative space charge that interacts with the proton beam. This leads to an aggregation of the proton beam around the solenoid's axis and therefore to a stronger focusing effect. The collimation and transport of laser-accelerated protons is the first step to provide these unique beams for further applications like post-acceleration by conventional accelerator structures.

Harres, K.; Alber, I.; Tauschwitz, A.; Bagnoud, V.; Daido, H.; Günther, M.; Nürnberg, F.; Otten, A.; Schollmeier, M.; Schütrumpf, J.; Tampo, M.; Roth, M.

2010-08-01

237

Polymer surface treatment with particle beams  

DOEpatents

A polymer surface and near surface treatment process produced by irradiation with high energy particle beams is disclosed. The process is preferably implemented with pulsed ion beams. The process alters the chemical and mechanical properties of the polymer surface in a manner useful for a wide range of commercial applications. 16 figs.

Stinnett, R.W.; VanDevender, J.P.

1999-05-04

238

Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources  

SciTech Connect

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

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

2009-03-20

239

Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources  

Microsoft Academic Search

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

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

2009-01-01

240

Strategies for mitigating the ionization-induced beam head erosion problem in an electron-beam-driven plasma wakefield accelerator  

NASA Astrophysics Data System (ADS)

Strategies for mitigating ionization-induced beam head erosion in an electron-beam-driven plasma wakefield accelerator (PWFA) are explored when the plasma and the wake are both formed by the transverse electric field of the beam itself. Beam head erosion can occur in a preformed plasma because of a lack of focusing force from the wake at the rising edge (head) of the beam due to the finite inertia of the electrons. When the plasma is produced by field ionization from the space charge field of the beam, the head erosion is significantly exacerbated due to the gradual recession (in the beam frame) of the 100% ionization contour. Beam particles in front of the ionization front cannot be focused (guided) causing them to expand as in vacuum. When they expand, the location of the ionization front recedes such that even more beam particles are completely unguided. Eventually this process terminates the wake formation prematurely, i.e., well before the beam is depleted of its energy. Ionization-induced head erosion can be mitigated by controlling the beam parameters (emittance, charge, and energy) and/or the plasma conditions. In this paper we explore how the latter can be optimized so as to extend the beam propagation distance and thereby increase the energy gain. In particular we show that, by using a combination of the alkali atoms of the lowest practical ionization potential (Cs) for plasma formation and a precursor laser pulse to generate a narrow plasma filament in front of the beam, the head erosion rate can be dramatically reduced. Simulation results show that in the upcoming “two-bunch PWFA experiments” on the FACET facility at SLAC national accelerator laboratory the energy gain of the trailing beam can be up to 10 times larger for the given parameters when employing these techniques. Comparison of the effect of beam head erosion in preformed and ionization produced plasmas is also presented.

An, W.; Zhou, M.; Vafaei-Najafabadi, N.; Marsh, K. A.; Clayton, C. E.; Joshi, C.; Mori, W. B.; Lu, W.; Adli, E.; Corde, S.; Litos, M.; Li, S.; Gessner, S.; Frederico, J.; Hogan, M. J.; Walz, D.; England, J.; Delahaye, J. P.; Muggli, P.

2013-10-01

241

Characteristics of an electron-beam rocket pellet accelerator  

SciTech Connect

An electron-beam rocket pellet accelerator has been designed, built, assembled, and tested as a proof-of-principle (POP) apparatus. The main goal of accelerators based on this concept is to use intense electron-beam heating and ablation of a hydrogen propellant stick to accelerate deuterium and/or tritium pellets to ultrahigh speeds (10 to 20 km/s) for plasma fueling of next-generation fusion devices such as the International Thermonuclear Engineering Reactor (ITER). The POP apparatus is described and initial results of pellet acceleration experiments are presented. Conceptual ultrahigh-speed pellet accelerators are discussed. 14 refs., 8 figs.

Tsai, C.C.; Foster, C.A.; Schechter, D.E.

1989-01-01

242

Novel Module for Plasma Wakefield Acceleration of a Positron Beam  

SciTech Connect

A novel approach for studying positron acceleration physics without an external positron source is developed. This scheme uses an e- beam to both create positrons in a target before the plasma and to excite the wake that accelerates these positrons. 2-D PIC simulations show that ultra-short e+ bunches can be focused and accelerated.

Wang, X.; Muggli, P.; Katsouleas, T. [University of Southern California, Los Angeles, CA 90007 (United States); Ischebeck, R. [Stanford Linear Accelerator Center, Stanford, CA 94025 (United States); Joshi, C. [University of California at Los Angeles, Los Angeles, CA 90095 (United States)

2006-11-27

243

Induced radioactivity in and around high-energy particle accelerators.  

PubMed

Particle accelerators and their surroundings are locations of residual radioactivity production that is induced by the interaction of high-energy particles with matter. This paper gives an overview of the principles of activation caused at proton accelerators, which are the main machines operated at Conseil Européen pour la Recherche Nucléaire. It describes the parameters defining radio-nuclide production caused by beam losses. The second part of the paper concentrates on the analytic calculation of activation and the Monte Carlo approach as it is implemented in the FLUKA code. Techniques used to obtain, on the one hand, estimates of radioactivity in Becquerel and, on the other hand, residual dose rates caused by the activated material are discussed. The last part of the paper focuses on experiments that allow for benchmarking FLUKA activation calculations and on simulations used to predict activation in and around high-energy proton machines. In that respect, the paper addresses the residual dose rate that will be induced by proton-proton collisions at an energy of two times 7 TeV in and around the Compact Muon Solenoid (CMS) detector. Besides activation of solid materials, the air activation expected in the CMS cavern caused by this beam operation is also discussed. PMID:21697180

Vincke, Helmut; Theis, Chris; Roesler, Stefan

2011-06-22

244

Beam collimation and energy spectrum compression of laser-accelerated proton beams using solenoid field and RF cavity  

NASA Astrophysics Data System (ADS)

This paper presents a new method of laser produced proton beam collimation and spectrum compression using a combination of a solenoid field and a RF cavity. The solenoid collects laser-driven protons efficiently within an angle that is smaller than 12 degrees because it is mounted few millimeters from the target, and collimates protons with energies around 2.3 MeV. The collimated proton beam then passes through a RF cavity to allow compression of the spectrum. Particle-in-cell (PIC) simulations demonstrate the proton beam transport in the solenoid and RF electric fields. Excellent energy compression and collection efficiency of protons are presented. This method for proton beam optimization is suitable for high repetition-rate laser acceleration proton beams, which could be used as an injector for a conventional proton accelerator.

Teng, J.; Gu, Y. Q.; Zhu, B.; Hong, W.; Zhao, Z. Q.; Zhou, W. M.; Cao, L. F.

2013-11-01

245

A Simplified Model for the Acceleration of Cosmic Ray Particles  

ERIC Educational Resources Information Center

|Two important questions concerning cosmic rays are: Why are electrons in the cosmic rays less efficiently accelerated than nuclei? How are particles accelerated to great energies in ultra-high energy cosmic rays? In order to answer these questions we construct a simple model of the acceleration of a charged particle in the cosmic ray. It is not…

Gron, Oyvind

2010-01-01

246

Phase and amplitude considerations for the Two-Beam Accelerator  

SciTech Connect

Phase and amplitude considerations are made for a Two-Beam Accelerator and analytic formulas are obtained expressing the phase and amplitude errors in terms of magnetic wiggler errors, beam energy errors, beam current errors, and microwave field amplitude errors. The necessity of phase and amplitude control is shown and schemes are proposed which can accomplish this control.

Kuenning, R.W.; Sessler, A.M.; Wurtele, J.S.

1985-02-01

247

Polymeric flocculants processing by accelerated electron beams and microwave heating  

Microsoft Academic Search

Results obtained by accelerated electron beam, microwave and simultaneous microwave and electron beam application in the chemistry of acrylamide and acrylic acid copolymers (polymeric flocculants used for wastewater treatment) are presented. Comparative results concerning the molecular weight and Huggins’ constant for the acrylamide and acrylic acid copolymers obtained by classical heating, microwave heating, electron beam irradiation and simultaneous microwave and

Diana I. Martin; Elena Mateescu; Gabriela Craciun; Daniel Ighigeanu; Adelina Ighigeanu

2002-01-01

248

ATA (Advanced Test Accelerator) beam transport experiment: Optical data  

Microsoft Academic Search

Optical data showing emittance growth through the Advanced Test Accelerator (ATA) beam pulse have been obtained using a new beam profile diagnostic, Cerenkov radiation emitted from a quartz foil inserted into the path of the electron beam. This diagnostic gave extremely bright optical emissions which allowed productive operation of a streak camera in addition to the gated 2-D image-intensified CCD

Y. P. Chong; P. Lee; F. J. Deadrick; D. G. Hirzel; J. S. Kallman; J. F. Poulter; W. E. Rivera; P. L. Stephan

1988-01-01

249

Gated Irradiation With Scanned Particle Beams  

SciTech Connect

Purpose: To demonstrate mitigation of the interplay effects of scanned particle beams and residual target motion within a gating window by increased overlap of pencil beams. Methods and Materials: Lateral overlap was increased by increasing the pencil beam widths or by decreasing the distance between the pencil beams (scan grid). Longitudinal overlap was increased by reducing the distance between iso-range slices. For scanned carbon ion beams, simulation studies were performed and validated experimentally to determine the required parameters for different residual motion characteristics. The dose distributions were characterized by the maximal local deviations representing local over- and underdosage. Results: For residual lateral motion, the local deviations were <5% for 2, 4, and 7 mm residual motion within the gating window for a 2-mm scan grid and pencil beams of 10, 14, and 18 mm full width at half maximum, respectively. Decreasing the iso-range slice distance from 3 mm to 1 mm effectively mitigated {<=}10 mm water-equivalent range changes. Experimental data reproduced the simulation results. Conclusion: In charged particle therapy with a scanned beam, interplay effects between gated beam delivery and residual target motion can be decreased effectively by increasing the overlap between pencil beams laterally, as well as longitudinally.

Bert, Christoph [Gesellschaft fuer Schwerionenforschung, Abt. Biophysik, Darmstadt (Germany)], E-mail: c.bert@gsi.de; Gemmel, Alexander; Saito, Nami [Gesellschaft fuer Schwerionenforschung, Abt. Biophysik, Darmstadt (Germany); Rietzel, Eike [Gesellschaft fuer Schwerionenforschung, Abt. Biophysik, Darmstadt (Germany); Siemens Healthcare, Particle Therapy, Erlangen (Germany)

2009-03-15

250

Frontiers of particle beam physics.  

National Technical Information Service (NTIS)

First, a review is given of various highly-developed techniques for particle handling which are, nevertheless, being vigorously advanced at the present time. These include soft superconductor radio frequency cavities, hard superconductor magnets, cooling ...

A. M. Sessler

1989-01-01

251

The production of accelerated radioactive ion beams  

SciTech Connect

During the last few years, substantial work has been done and interest developed in the scientific opportunities available with accelerated radioactive ion beams (RIBs) for nuclear physics, astrophysics, and applied research. This interest has led to the construction, development, and proposed development of both first- and second-generation RIB facilities in Asia, North America, and Europe; international conferences on RIBs at Berkeley and Louvain-la-Neuve; and many workshops on specific aspects of RIB production and science. This paper provides a discussion of both the projectile fragmentation, PF, and isotope separator on-line, ISOL, approach to RIB production with particular emphasis on the latter approach, which employs a postaccelerator and is most suitable for nuclear structure physics. The existing, under construction, and proposed facilities worldwide are discussed. The paper draws heavily from the CERN ISOLDE work, the North American IsoSpin Laboratory (ISL) study, and the operating first-generation RIB facility at Louvain-la-Neuve, and the first-generation RIB project currently being constructed at ORNL.

Olsen, D.K.

1993-11-01

252

The IBA Rhodotron: an industrial high-voltage high-powered electron beam accelerator for polymers radiation processing  

Microsoft Academic Search

The Rhodotron is a high-voltage, high-power electron beam accelerator based on a design concept first proposed in 1989 by J. Pottier of the French Atomic Agency, Commissariat à l'Energie Atomique (CEA). In December 1991, the Belgian particle accelerator manufacturer, Ion Beam Applications s.a. (IBA) entered into an exclusive agreement with the CEA to develop and industrialize the Rhodotron. Electron beams

Marc Van Lancker; Arnold Herer; Marshall R. Cleland; Yves Jongen; Michel Abs

1999-01-01

253

Possibility of using "sliding" particles in accelerators and tunable sources of coherent ultraviolet radiation  

NASA Astrophysics Data System (ADS)

We consider "sliding" particles (electrons or ions) which move in vacuum in a potential well at a small distance from a corrugated dielectric surface. We consider a way to stabilize the beam position above the plate, avoiding the bombardment of the plate by the particles. We discuss possible ways to create beams of such "sliding" particles with the desired characteristics. It is proposed to use such "sliding" particles in accelerators and tunable sources of coherent ultraviolet radiation. It is shown, that in principle the laser effect can be observed at rather small currents of ultra-relativistic "sliding" electrons.

Namiot, V. A.; Shchurova, L. Yu.

2012-10-01

254

High quality electron beams from a plasma channel guided laser wakefield accelerator  

SciTech Connect

Laser driven accelerators, in which particles are accelerated by the electric field of a plasma wave driven by an intense laser, have demonstrated accelerating electric fields of hundreds of GV/m. These fields are thousands of times those achievable in conventional radiofrequency (RF) accelerators, spurring interest in laser accelerators as compact next generation sources of energetic electrons and radiation. To date however, acceleration distances have been severely limited by lack of a controllable method for extending the propagation distance of the focused laser pulse. The ensuing short acceleration distance results in low energy beams with 100% electron energy spread, limiting applications. Here we demonstrate that a relativistically intense laser can be guided by a preformed plasma density channel and that the longer propagation distance can result in electron beams of percent energy spread with low emittance and increased energy, containing >10{sup 9} electrons above 80 MeV. The preformed plasma channel technique forms the basis of a new class of accelerators, combining beam quality comparable to RF accelerators with the high gradients of laser accelerators to produce compact tunable high brightness electron and radiation sources.

Geddes, C.G.R.; Toth, Cs.; van Tilborg, J.; Esarey, E.; Schroeder, C.B.; Bruhwiler, D.; Nieter, C.; Cary, J.; Leemans, W.P.

2004-07-08

255

Observation of Beam Loading in a Laser-Plasma Accelerator  

SciTech Connect

Beam loading is the phenomenon which limits the charge and the beam quality in plasma based accelerators. An experimental study conducted with a laser-plasma accelerator is presented. Beam loading manifests itself through the decrease of the beam energy, the reduction of dark current, and the increase of the energy spread for large beam charge. 3D PIC simulations are compared to the experimental results and confirm the effects of beam loading. It is found that, in our experimental conditions, the trapped electron beams generate decelerating fields on the order of 1 (GV/m)/pC and that beam loading effects are optimized for trapped charges of about 20 pC.

Rechatin, C.; Ismail, A. Ben; Lim, J.; Faure, J.; Malka, V. [Laboratoire d'Optique Appliquee, ENSTA, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France); Davoine, X.; Lefebvre, E. [CEA, DAM, DIF, Bruyeres-le-Chatel, 91297 Arpajon (France); Lifschitz, A. [Laboratoire d'Optique Appliquee, ENSTA, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France); Laboratoire de Physique des Gaz et des Plasmas, CNRS, UMR 8578, Universite Paris XI, Batiment 210, 91405 Orsay cedex (France)

2009-11-06

256

Radioactive beams with the HHIRF accelerators  

SciTech Connect

There is an increasing interest in radioactive ion beams for astrophysics and nuclear physics research and applied programs. This interest has led to an International Conference on Radioactive Nuclear Beams and a Workshop on the Science of Intense Radioactive Ion Beams. In addition, a steering committee has been formed to consider the development of a very large and intense RIB facility in North America to produce both proton- and neutron-rich beams. This report discusses development of these beams.

Olsen, D.K.; Alton, G.D.; Baktash, C.; Dowling, D.T.; Garrett, J.D.; Haynes, D.L.; Jones, C.M.; Juras, R.C., Lane, S.N.; Lee, I.Y.; Meigs, M.J.; Mills, G.D.; Mosko, S.W.; Tatum, B.A. Toth, K.S. (Oak Ridge National Lab., TN (USA)); Carter, H.K. (UNISOR, Oak Ridge, TN (USA))

1991-01-01

257

Self-accelerating self-trapped optical beams.  

PubMed

We present self-accelerating self-trapped beams in nonlinear optical media, exhibiting self-focusing and self-defocusing Kerr and saturable nonlinearities, as well as a quadratic response. In Kerr and saturable media such beams are stable under self-defocusing and weak self-focusing, whereas for strong self-focusing the beams off-shoot solitons while their main lobe continues to accelerate. Self-accelerating self-trapped wave packets are universal, and can also be found in matter waves, plasma, etc. PMID:21699299

Kaminer, Ido; Segev, Mordechai; Christodoulides, Demetrios N

2011-05-26

258

Linear Accelerators  

SciTech Connect

In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

Sidorin, Anatoly [Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna (Russian Federation)

2010-01-05

259

Application of the Reduction of Scale Range in a Lorentz Boosted Frame to the Numerical Simulation of Particle Acceleration Devices.  

National Technical Information Service (NTIS)

It has been shown that it may be computationally advantageous to perform computer simulations in a boosted frame for a certain class of systems: particle beams interacting with electron clouds, free electron lasers, and laserplasma accelerators. However, ...

C. G. Geddes D. P. Grote F. Cormier-Michel J. Vay W. M. Fawle

2009-01-01

260

Particle beam generator using a radioactive source  

DOEpatents

The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

Underwood, D.G.

1993-03-30

261

Particle beam generator using a radioactive source  

DOEpatents

The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

Underwood, David G. (Naperville, IL)

1993-01-01

262

G4beamline Particle Tracking in Matter Dominated Beam Lines  

SciTech Connect

The G4beamline program is a useful and steadily improving tool to quickly and easily model beam lines and experimental equipment without user programming. It has both graphical and command-line user interfaces. Unlike most accelerator physics codes, it easily handles a wide range of materials and fields, being particularly well suited for the study of muon and neutrino facilities. As it is based on the Geant4 toolkit, G4beamline includes most of what is known about the interactions of particles with matter. We are continuing the development of G4beamline to facilitate its use by a larger set of beam line and accelerator developers. A major new feature is the calculation of space-charge effects. G4beamline is open source and freely available at http://g4beamline.muonsinc.com

T.J. Roberts, K.B. Beard, S. Ahmed, D. Huang, D.M. Kaplan

2011-03-01

263

Particle acceleration by intense auroral VLF turbulence  

SciTech Connect

Broadband turbulence in the lower-hybrid to plasma frequency range is found in a variety of forms in the supraauroral region, must notably as auroral his and VLF saucers. When the turbulence is intense, it is observed to be associated with ion conics (ions heated transverse to the geomagnetic field) and counter-streaming electron fluxes (heated in both directions parallel to the field). This tutorial will begin with a review of the dispersion and propagation characteristics of whistler resonance-cone waves, which comprise the turbulence, and go on to discuss the theories for the excitation of the turbulence. Plasma simulation and mesoscale (Monte Carlo) simulation techniques will be used to illustrate the interaction of the ambient plasma with the turbulence. These calculations will demonstrate how this interaction results in transverse heating of the ions and parallel heating of the electrons of the plasma, leading to the formation of the observed heated and accelerated particle fluxes.

Retterer, J.M.; Chang, T.; Jasperse, J.R.

1989-01-01

264

A Magnetorestrictive Tuning System for Particle Accelerators  

SciTech Connect

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

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

2005-05-16

265

Chaos-enhanced accelerated particle swarm optimization  

NASA Astrophysics Data System (ADS)

There are more than two dozen variants of particle swarm optimization (PSO) algorithms in the literature. Recently, a new variant, called accelerated PSO (APSO), shows some extra advantages in convergence for global search. In the present study, we will introduce chaos into the APSO in order to further enhance its global search ability. Firstly, detailed studies are carried out on benchmark problems with twelve different chaotic maps to find out the most efficient one. Then the chaotic APSO (CAPSO) will be compared with some other chaotic PSO algorithms presented in the literature. The performance of the CAPSO algorithm is also validated using three engineering problems. The results show that the CAPSO with an appropriate chaotic map can clearly outperform standard APSO, with very good performance in comparison with other algorithms and in application to a complex problem.

Gandomi, Amir Hossein; Yun, Gun Jin; Yang, Xin-She; Talatahari, Siamak

2013-02-01

266

Simulation of quasimonoenergetic electron beams produced by colliding pulse wakefield acceleration  

SciTech Connect

The collision of two laser pulses can inject electrons into a wakefield accelerator, and has been found to produce stable and tunable quasimonoenergetic electron beams [J. Faure et al., Nature 444, 737 (2006)]. This colliding pulse scheme is studied here with 3D particle-in-cell simulations. The results are successfully compared with experimental data, showing the accuracy of the simulations. The involved mechanisms (laser propagation, wake inhibition, electron heating and trapping, beam loading) are presented in detail. We explain their interplay effects on the beam parameters. The experimental variations of beam charge and energy with collision position are explained.

Davoine, X.; Lefebvre, E. [Departement de Physique Theorique et Appliquee, CEA/DIF, Bruyeres-le-Chatel, 91297 Arpajon (France); Faure, J.; Rechatin, C.; Malka, V. [Laboratoire d'Optique Appliquee, ENSTA, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France); Lifschitz, A. [Laboratoire d'Optique Appliquee, ENSTA, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France); Laboratoire de Physique des Gaz et Plasmas, CNRS UMR 8578, Universite Paris XI, Batiment 210, 91405 Orsay (France)

2008-11-15

267

Neutral particle beam alternative concept for ITER  

Microsoft Academic Search

An analysis of an ITER neutral particle beam system is presented. The analysis covers the neutralizer, ion dumps, pumping, and geometric aspects. The US beam concept for ITER consists of three or four clusters of beamlines delivering approximately 80 MW total of 1.6-MeV deuterium to three or four reactor ports. Each cluster has three self-contained beamlines featuring plasma neutralizers and

D. Sedgley; J. Brook; T. Luzzi; L. Deutsch

1989-01-01

268

Neutral-particle-beam production and injection  

SciTech Connect

This paper is divided into two sections: the first is a discussion of the interactions of neutral beams with confined plasmas, the second is concerned with the production and diagnosis of the neutral beams. In general we are dealing with atoms, molecules, and ions of the isotopes of hydrogen, but some heavier elements (for example, oxygen) will be mentioned. The emphasis will be on single-particle collisions; selected atomic processes on surfaces will be included.

Post, D.; Pyle, R.

1982-07-01

269

US particle accelerators at age 50  

SciTech Connect

Fifty years ago, a dramatic race was under way to see who would be first to accelerate protons to an energy high enough to disintegrate the atomic nucleus. This contest, coincidental with the birth of the American Institute of Physics, could be considered as the beginning of what was to become a Golden age of high-energy physics. The race might also be taken to mark the end of an Age of Innocence of nulcear physicists. Heretofore during an era to which all physicists look back with nostalgia, much of the fundamental knowledge about the nucleus had been by obtained the use of rather primitive experimental devices, followed by sophisticated analysis. Rutherford's famous ..cap alpha..-particle scattering experiment is a case-in-point: a little string and sealing wax and not much else. Not much, that is, except great leaps of reason and imagination. In the future, in addition to make-do skills, physicists were going to have to master arcane techniques, such as those of mechanical and electrical engineers. Indeed they would have to invent a whole new technology of accelerator building in order to explore the inside of the nucleus and to identify and study its constituent parts.

Wilson, R.R.

1981-11-01

270

US Particle Accelerators at Age 50.  

ERIC Educational Resources Information Center

|Reviews the development of accelerators over the past 50 years. Topics include: types of accelerators, including cyclotrons; sociology of accelerators (motivation, financing, construction, and use); impact of war; national laboratories; funding; applications; future projects; foreign projects; and international collaborations. (JN)|

Wilson, R. R.

1981-01-01

271

Advanced treatment planning methods for efficient radiation therapy with laser accelerated proton and ion beams  

SciTech Connect

Purpose: Laser plasma acceleration can potentially replace large and expensive cyclotrons or synchrotrons for radiotherapy with protons and ions. On the way toward a clinical implementation, various challenges such as the maximum obtainable energy still remain to be solved. In any case, laser accelerated particles exhibit differences compared to particles from conventional accelerators. They typically have a wide energy spread and the beam is extremely pulsed (i.e., quantized) due to the pulsed nature of the employed lasers. The energy spread leads to depth dose curves that do not show a pristine Bragg peak but a wide high dose area, making precise radiotherapy impossible without an additional energy selection system. Problems with the beam quantization include the limited repetition rate and the number of accelerated particles per laser shot. This number might be too low, which requires a high repetition rate, or it might be too high, which requires an additional fluence selection system to reduce the number of particles. Trying to use laser accelerated particles in a conventional way such as spot scanning leads to long treatment times and a high amount of secondary radiation produced when blocking unwanted particles. Methods: The authors present methods of beam delivery and treatment planning that are specifically adapted to laser accelerated particles. In general, it is not necessary to fully utilize the energy selection system to create monoenergetic beams for the whole treatment plan. Instead, within wide parts of the target volume, beams with broader energy spectra can be used to simultaneously cover multiple axially adjacent spots of a conventional dose delivery grid as applied in intensity modulated particle therapy. If one laser shot produces too many particles, they can be distributed over a wider area with the help of a scattering foil and a multileaf collimator to cover multiple lateral spot positions at the same time. These methods are called axial and lateral clustering and reduce the number of particles that have to be blocked in the beam delivery system. Furthermore, the optimization routine can be adjusted to reduce the number of dose spots and laser shots. The authors implemented these methods into a research treatment planning system for laser accelerated particles. Results: The authors' proposed methods can decrease the amount of secondary radiation produced when blocking particles with wrong energies or when reducing the total number of particles from one laser shot. Additionally, caused by the efficient use of the beam, the treatment time is reduced considerably. Both improvements can be achieved without extensively changing the quality of the treatment plan since conventional intensity modulated particle therapy usually includes a certain amount of unused degrees of freedom which can be used to adapt to laser specific properties. Conclusions: The advanced beam delivery and treatment planning methods reduce the need to have a perfect laser-based accelerator reproducing the properties of conventional accelerators that might not be possible without increasing treatment time and secondary radiation to the patient. The authors show how some of the differences to conventional beams can be overcome and efficiently used for radiation treatment.

Schell, Stefan; Wilkens, Jan J. [Department of Radiation Oncology, Technische Universitaet Muenchen, Klinikum Rechts der Isar, Ismaninger Str. 22, 81675 Muenchen (Germany)

2010-10-15

272

The use of particle accelerators for space projects  

NASA Astrophysics Data System (ADS)

With the introduction of CMOS technology radiation effects in components became an important issue in satellite and space mission projects. At the end of the cold war, the market of radiation hard (RadHard) components crashed and during the 90's their fabrication practically stopped. The use of ''commercial-off-the-shelf'' (COTS) components became more common but required increased evaluation activities at radiation test sites. Component manufacturers and space project engineers were directed towards these test sites, in particular, towards particle accelerators. Many accelerator laboratories developed special beam lines and constructed dedicated test areas for component evaluations. The space environment was simulated at these test sites and components were tested to levels often exceeding mission requirements. In general, space projects environments were predicted in respects to particle mass and energy distributions with the expected fluxes and fluences. In order to validate this information in tests, concepts like stopping power, linear energy transfer, ion penetration ranges etc. have to be understood. The knowledge from the component structure also defines the way of irradiation. For example, the higher ion energies resulting in much deeper ion penetration ranges allow successful reverse side irradiation of thinned Integrated Circuits (ICs). So overall increased demands for radiation testing attracted the European Space Agency (ESA) to the JYFL-accelerator laboratory of the University of Jyväskylä, Finland. A contract was signed between ESA and JYFL for the development of a ''High Penetrating Heavy Ion Test Site'' [1]. Following one year development, this test site was commissioned in May 2005. This paper addresses the various issues around the JYFL laboratory with its accelerator and radiation effects facility as the focal point in service of component evaluations for the space community.

Virtanen, Ari

2006-05-01

273

A 1-D Computer Simulation Model of Collective Ion Acceleration by Linear Electron Beams.  

National Technical Information Service (NTIS)

A 1-d electrostatic and relativistic particle code has been built in order to simulate a self-consistent way the time-dependent behavior of collective ion acceleration produced by linear electron beams injected into evacuated drift tubes. The simulation r...

A. Sternlieb H. S. Ulm

1979-01-01

274

Multi-stage intense ion beam electrostatic accelerator for ICF  

SciTech Connect

The design of a multi-aperture, channel focused, multi-stage low /beta/ electrostatic accelerator is made to produce well controlled intense light ion beams as drivers of Inertial Confinement Fusion (ICF) targets. Unlike the case of diode accelerators, the Light Ion Fusion Experiment (LIFE) accelerator system contains separate-function elements to launch 3 to 10 Mev, 23 kA accelerated current, He/sup +/ beams in 400 ns pulses where 20:1 axial pulse compression would occur during the neutralized and ballistically focused transport. Each beam line would impart 50 kJ implosion energy in approximately 20 ns on 5-6 mm radius targets located 10 m downstream and a system of 40 beam lines would deliver 2 MJ. 4 refs.

Guiragossian, Z.G.T.; Orthel, J.L.

1981-06-01

275

Studies of beam dynamics in relativistic klystron two-beam accelerators  

SciTech Connect

Two-beam accelerators (TBAs) based upon free-electron lasers (FELs) or relativistic klystrons (RK-TBAs) have been proposed as efficient power sources for next generation high-energy linear colliders. Studies have demonstrated the possibility of building TBAs from X-band ({approximately}8-12 GHz) through Ka band ({approximately} 30-35 GHz) frequency regions. Provided that further prototyping shows stable beam propagation with minimal current loss and production of good quality, high-power rf fields, this technology is compatible with current schemes for electron-positron colliders in the multi-TeV center-of-mass scale. A new method of simulating the beam dynamics in accelerators of this type has been developed in this dissertation. There are three main components to this simulation. The first is a tracking algorithm to generate nonlinear transfer maps for pushing noninteracting particles through the external fields. The second component is a 3D Particle-In-Cell (PIC) algorithm that solves a set of Helmholtz equations for the self-fields, including the conducting boundary condition, and generates impulses that are interleaved with the nonlinear maps by means of a split-operation algorithm. The Helmholtz equations are solved by a multi-grid algorithm. The third component is an equivalent circuit equation solver that advances the modal rf cavity fields in time due to excitation by the modulated beam. The RTA project is described, and the simulation code is used to design the latter portions of the experiment. Detailed calculations of the beam dynamics and of the rf cavity output are presented and discussed. A beamline design is presented that will generate nearly 1.2 GW of power from 40 input, gain, and output rv cavities over a 10 m distance. The simulations show that beam current losses are acceptable, and that longitudinal and transverse focusing techniques are sufficient capable of maintaining a high degree of beam quality along the entire beamline. Additional experimental efforts are also described.

Lidia, Steven M.

1999-11-01

276

Beam collimation and transport of quasineutral laser-accelerated protons by a solenoid field  

NASA Astrophysics Data System (ADS)

This article reports about controlling laser-accelerated proton beams with respect to beam divergence and energy. The particles are captured by a pulsed high field solenoid with a magnetic field strength of 8.6 T directly behind a flat target foil that is irradiated by a high intensity laser pulse. Proton beams with energies around 2.3 MeV and particle numbers of 1012 could be collimated and transported over a distance of more than 300 mm. In contrast to the protons the comoving electrons are strongly deflected by the solenoid field. They propagate at a submillimeter gyroradius around the solenoid's axis which could be experimentally verified. The originated high flux electron beam produces a high space charge resulting in a stronger focusing of the proton beam than expected by tracking results. Leadoff particle-in-cell simulations show qualitatively that this effect is caused by space charge attraction due to the comoving electrons. The collimation and transport of laser-accelerated protons is the first step to provide these unique beams for further applications such as postacceleration by conventional accelerator structures.

Harres, K.; Alber, I.; Tauschwitz, A.; Bagnoud, V.; Daido, H.; Günther, M.; Nürnberg, F.; Otten, A.; Schollmeier, M.; Schütrumpf, J.; Tampo, M.; Roth, M.

2010-02-01

277

High energy electron beam processing experiments with induction accelerators  

Microsoft Academic Search

Induction accelerators are capable of producing very high electron beam power for processing at energies of 1–10 MeV. A high energy electron beam (HEEB) material processing system based on all-solid-state induction accelerator technology is in operation at Science Research Laboratory. The system delivers 50 ns 500 A current pulses at 1.5 MeV and is capable of operating at high power

D. L. Goodman; D. L. Birx; V. R. Dave

1995-01-01

278

Sterilization of Mail by Means of an Electron Beam Accelerator  

Microsoft Academic Search

In view of the recent cases of postal bioterrorism with the use of anthrax spores in sealed envelopes (see [11] and http:\\/\\/www. bt.cdc.gov), we experimentally checked and demonstrated the possibility of using an industrial electron beam accelerator for sterilization of mail. Industrial electron beam accelerators are widely used for sterilization of medical equipment, drugs, food, and packing materials. In some

V. L. Auslender; V. A. Vedernikov; M. A. Grachev; V. V. Drukker; A. I. Korchagin; E. P. Kruglyakov; A. M. Kudryavtsev; N. S. Kulikova; O. G. Netsvetaeva; O. N. Pavlova; V. V. Parfenova; E. A. Semenova; V. I. Serbin; I. A. Terkina; A. V. Tkov; E. P. Chebykin

2002-01-01

279

Beam dynamics in a long-pulse linear induction accelerator  

SciTech Connect

The second axis of the Dual Axis Radiography of Hydrodynamic Testing (DARHT) facility produces up to four radiographs within an interval of 1.6 microseconds. It accomplishes this by slicing four micro-pulses out of a long 1.8-kA, 16.5-MeV electron beam pulse and focusing them onto a bremsstrahlung converter target. The long beam pulse is created by a dispenser cathode diode and accelerated by the unique DARHT Axis-II linear induction accelerator (LIA). Beam motion in the accelerator would be a problem for radiography. High frequency motion, such as from beam breakup instability, would blur the individual spots. Low frequency motion, such as produced by pulsed power variation, would produce spot to spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it.

Ekdahl, Carl [Los Alamos National Laboratory; Abeyta, Epifanio O [Los Alamos National Laboratory; Aragon, Paul [Los Alamos National Laboratory; Archuleta, Rita [Los Alamos National Laboratory; Cook, Gerald [Los Alamos National Laboratory; Dalmas, Dale [Los Alamos National Laboratory; Esquibel, Kevin [Los Alamos National Laboratory; Gallegos, Robert A [Los Alamos National Laboratory; Garnett, Robert [Los Alamos National Laboratory; Harrison, James F [Los Alamos National Laboratory; Johnson, Jeffrey B [Los Alamos National Laboratory; Jacquez, Edward B [Los Alamos National Laboratory; Mc Cuistian, Brian T [Los Alamos National Laboratory; Montoya, Nicholas A [Los Alamos National Laboratory; Nath, Subrato [Los Alamos National Laboratory; Nielsen, Kurt [Los Alamos National Laboratory; Oro, David [Los Alamos National Laboratory; Prichard, Benjamin [Los Alamos National Laboratory; Rose, Chris R [Los Alamos National Laboratory; Sanchez, Manolito [Los Alamos National Laboratory; Schauer, Martin M [Los Alamos National Laboratory; Seitz, Gerald [Los Alamos National Laboratory; Schulze, Martin [Los Alamos National Laboratory; Bender, Howard A [Los Alamos National Laboratory; Broste, William B [Los Alamos National Laboratory; Carlson, Carl A [Los Alamos National Laboratory; Frayer, Daniel K [Los Alamos National Laboratory; Johnson, Douglas E [Los Alamos National Laboratory; Tom, C Y [Los Alamos National Laboratory; Trainham, C [Los Alamos National Laboratory; Williams, John [Los Alamos National Laboratory; Scarpetti, Raymond [LLNL; Genoni, Thomas [VOSS; Hughes, Thomas [VOSS; Toma, Carsten [VOSS

2010-01-01

280

Transverse envelope analysis for accelerating relativistic electron beams in a linear accelerator as a photon source  

NASA Astrophysics Data System (ADS)

Since recent progress of electron guns extends the application of linear accelerators to photon radiation sources, the design and optimization of transverse beam optics over a linear accelerator become important. In this paper, we propose a transverse beam envelope analysis for accelerating beams in a linear accelerator using symplectic matrices based on a normalized emittance. This approach allows a description of the transverse envelope function, which reflects the characteristics of beam optics. Since the envelope function is described in the same phase space as photon radiation, it provides an effective and powerful tool for the design and optimization of the beam optics as a photon source. The emittance based formalism of the beam envelope, which was previously described by Douglas, Kewisch, and York, is first introduced for impulse acceleration, and then extended to a thick accelerator structure. The transverse beam envelope analyses, such as error sensitivity, chromatic aberration, and emittance growth, are presented by applying second-order perturbation treatment to a formulated matrix describing a quasi-periodic lattice in the linear accelerator system.

Hara, Toru; Togawa, Kazuaki; Tanaka, Hitoshi

2010-12-01

281

{open_quotes}Accelerators and Beams,{close_quotes} multimedia computer-based training in accelerator physics  

Microsoft Academic Search

We are developing a set of computer-based tutorials on accelerators and charged-particle beams under an SBIR grant from the DOE. These self-paced, interactive tutorials, available for Macintosh and Windows platforms, use multimedia techniques to enhance the user{close_quote}s rate of learning and length of retention of the material. They integrate interactive {open_quotes}On-Screen Laboratories,{close_quotes} hypertext, line drawings, photographs, two- and three-dimensional animations,

R. R. Silbar; A. A. Browman; W. C. Mead; R. A. Williams

1999-01-01

282

Aging of organic materials around high-energy particle accelerators  

NASA Astrophysics Data System (ADS)

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

Tavlet, M.

1997-08-01

283

High Power Particle Beams and Pulsed Power for Industrial Applications  

NASA Astrophysics Data System (ADS)

Several industrial scale projects with economic and ecologic potential are presently emanating from research and development in the fields of high power particle beams and pulsed power in Europe. Material surface modifications with large area pulsed electron beams are used to protect high temperature gas turbine blades and steel structures in Pb/Bi cooled accelerator driven nuclear reactor systems against oxidation and corrosion respectively. Channel spark electron beams are applied to deposit bio-compatible or bio-active layers on medical implants. Cell membranes are perforated with strong pulsed electric fields to extract nutritive substances or raw materials from the cells and to kill bacteria for sterilization of liquids. Eletrodynamic fragmentation devices are developed to reutilize concrete aggregates for the production of high quality secondary concrete. All activities have a large potential to contribute to a more sustainable economy.

Bluhm, Hansjoachim; An, Wladimir; Engelko, Wladimir; Giese, Harald; Frey, Wolfgang; Heinzel, Annette; Hoppé, Peter; Mueller, Georg; Schultheiss, Christoph; Singer, Josef; Strässner, Ralf; Strauß, Dirk; Weisenburger, Alfons; Zimmermann, Fritz

2002-12-01

284

Polarization of fast particle beams by collisional pumping  

DOEpatents

Method and apparatus for highly polarizing a fast beam of particles by collisional pumping, including generating a fast beam of particles, and also generating a thick electron-spin-polarized medium positioned as a target for the beam. The target is made sufficiently thick to allow the beam to interact with the medium to produce collisional pumping whereby the beam becomes highly polarized.

Stearns, J. Warren (Castro Valley, CA); Kaplan, Selig N. (El Cerrito, CA); Pyle, Robert V. (Berkeley, CA); Anderson, L. Wilmer (Madison, WI); Ruby, Lawrence (Berkeley, CA); Schlachter, Alfred S. (Oakland, CA)

1988-01-01

285

Low and Medium Energy Beam Acceleration in High Intensity Linacs  

Microsoft Academic Search

In the past two years accelerator builders have published papers describing mature designs of no fewer than 7 new high-performance proton linacs. These machines are typically designed to deliver multi- megawatt beams for applications in pure and applied research. All of these machines use the radio-frequency quadrupole (RFQ) linac for the first stage of acceleration to reach an energy of

James Stovall

2004-01-01

286

Calibration and application of medical particle accelerators to space radiation experiments  

NASA Astrophysics Data System (ADS)

In this paper, we introduce radioisotope facilities and medical particle accelerators that can be applied to space radiation experiments and the experimental conditions required by the space radiation experiments. Space radiation experiments on the ground are critical in determining the lifetimes of satellites and in choosing or preparing the appropriate electrical parts to assure the designated mission lifetime. Before the completion of building the 100-MeV proton linear accelerator in Gyeongju, or even after the completion, the currently existing proton accelerators for medical purposes could suggest an alternative plan. We have performed experiments to calibrate medical proton beam accelerators to investigate whether the beam conditions are suitable for applications to space radiation experiments. Based on the calibration results, we propose reference beam operation conditions for space radiation experiments.

Ryu, Kwangsun; Park, Mi-Young; Chae, Jang-Soo; Yoon, Sang-Pil; Shin, Dong-Ho

2012-07-01

287

Electron Beam Generation from Self-Modulated Laser Wakefileld Accelerator  

Microsoft Academic Search

From 2001, the laser wakefield accelerator has been studied at the Center for Advanced Accelerator (CAA) of Korea Electrotechnology Research Institute (KERI). For this study, 2 TW, 700 fs Ti: sapphire and Nd: Glass hybrid type laser was installed and self-modulated laser wakefiled acceleration (SM-LWFA) has been tried as a first step. Recently, electron beam generation from SM-LWFA is successfully

Changbum Kim; Guang-Hoon Kim; Nasr Hafz; Hyyong Suk; In Soo Ko

2004-01-01

288

Generation of multi-giga-electron-volt monoenergetic electron beams via laser wakefield acceleration  

NASA Astrophysics Data System (ADS)

In plasma-based acceleration a particle bunch surfs a plasma wave, driven by a laser or a particle beam, in order to achieve high energy in a very short distance. Powerful modern drivers create strongly nonlinear wavefields in which the plasma electrons are radially expelled. These wakefields can generate well-defined particle beams in what is referred to as the "blowout" regime. In this dissertation we study with theory and simulations some key physics of the blowout regime and offer methods for designing plasma-based accelerators which are stable, efficient and generate particle beams with good quality. Starting from a phenomenological theory, originally presented in Ref. [51], which includes the concepts of nonlinear multi-dimensional wake excitation, local pump depletion, dephasing and laser guiding, we design laser wakefield accelerators which accelerate electron beams efficiently in a single stage. Simulations carried out using the Particle-In-Cell (PIC) code QuickPIC confirm much of the theoretical predictions. They show that in this nonlinear blowout regime, the laser excites a stable wake over distances hundreds of Rayleigh lengths long, as long as its spot size and duration are properly matched, kpw0 = optauL = 2a0. In the simulations a0 is held fixed at 2 and the plasma density is decreased while the spot size is kept matched. Stages that provide an average gradient 3.6GV/m (7.2 GV/m) with a final energy of 100GeV (25 GeV) were demonstrated. We discuss the optimal laser profile of an ultraintense pulse used for plasma-based acceleration and develop a method for describing how such a laser evolves. The first beam loading theory for electrons in nonlinear wakes is developed starting from the work in Ref. [48, 49]. By assuming that the blowout radius is large, analytical solutions for the shape of the bubble and the loaded wakefield are derived. It is found analytically and confirmed in PIC simulations with OSIRIS, that beam-loading efficiencies exceeding 90% can be achieved while the energy spread of the accelerating electron bunch is essentially conserved for trapezoidally-shaped trailing beams. Analytical solutions for flat-top current profiles are also calculated and it is found through simulations that the results are similar to those for Gaussian-shaped beams. Based on these solutions the amount of loaded charge is calculated for a given acceleration gradient.

Tzoufras, Michail

289

Beam extraction from a Hall-type ion accelerator  

SciTech Connect

Fundamental characteristics of beam extraction from a Hall-type accelerator working with permanent magnets were investigated. Ions were extracted by an axial electric field E{sub z} in a small annular plasma channel with a radial magnetic field B{sub r}. Effects of discharge current and voltage, length of discharge channel, and gas flow rate were examined. It can deliver a large beam current density of more than 100 mA/cm{sup 2} with low beam energy of 50 eV. By biasing an additional plasma chamber attached at the extraction area, the beam energy was controlled independently of the beam current.

Ando, Akira; Tashiro, Masashi; Hitomi, Keiichiro; Hattori, Kunihiko; Inutake, Masaaki [Department of Electrical Engineering, School of Engineering, Tohoku University, Miyagi 980-8579 (Japan)

2008-02-15

290

Acceleration, beaming, and synchrotron radiation above the 160 MeV limit from relativistic pair reconnection  

NASA Astrophysics Data System (ADS)

Magnetic reconnection converts magnetic field energy into particle kinetic energy, accelerating particles to sufficient energies to emit gamma-ray synchrotron radiation in astrophysical contexts, possibly including pulsar wind nebulae, Gamma-Ray Bursts, and blazar jets. A balance between acceleration (by the electric field E) and synchrotron braking (while orbiting a B-field line) limits particle energy so that synchrotron processes cannot emit photons above about 160 MeV, unless E > B. However, short, intense gamma-ray flares of much higher energies have recently been observed in the Crab nebula. This work demonstrates, using 2D simulations, that reconnection in relativistic electron-positron pair plasmas can accelerate particles in Speiser orbits around the magnetic null (where E > B) such that the particles can emit synchrotron photons above the 160 MeV limit. Furthermore, reconnection bunches particles and focuses them into beams; high-energy synchrotron radiation is also strongly beamed, and the sweeping of the beam across the observer's line of sight can explain the fast time variability of the flares.

Werner, Gregory; Cerutti, Benoit; Uzdensky, Dmitri; Begelman, Mitchell

2013-04-01

291

Beam dynamics in the Advanced Test Accelerator (ATA)  

SciTech Connect

We will review the performance of the Advanced Test Accelerator, a 50 MeV, 10 KA induction linac. The discussion will cover the operation of the plasma cathode electron source, beam transport throughout the accelerator, and transverse instabilities. Particular emphasis will be placed on the beam breakup instability and on the methods used to minimize it. These include a program of design changes that lead to an order of magnitude reduction in the Q's of the accelerator cavity modes and optimization of the transport tune.

Caporaso, G.J.; Barletta, W.A.; Birx, D.L.; Briggs, R.J.; Chong, Y.P.; Cole, A.G.; Fessenden, T.J.; Hester, R.E.; Lauer, E.J.; Neil, V.K.

1983-09-28

292

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC  

Microsoft Academic Search

to couple the THUNDER undulator to the LOASIS Lawrence Berkeley National Laboratory (LBNL) laser wakefield accelerator (LWFA). Currently the LWFA has achieved quasi-monoenergetic electron beams with energies up to 1 GeV. These ultra-short, high-peak-current, electron beams are ideal for driving a compact XUV free electron laser (FEL). Understanding the electron beam properties such as the energy spread and emittance is

M. S. Bakeman; W. M. Fawley; W. P. Leemans; K. Nakamura; K. E. Robinson; C. B. Schroeder; C. Toth

2009-01-01

293

Injection of high brightness H- beams into RFQ accelerators  

NASA Astrophysics Data System (ADS)

The state of the art in low-energy beam transport (LEBT) of high brightness H- beams from the source to the RFQ accelerator using gas focusing and solenoid or quadrupole magnets is reviewed. Proposed advanced LEBT schemes with electric focusing elements presently under investigation avoid charge neutralization and hence the beam loss and emittance degradation inherent in gas focusing systems. Results of conceptual design studies for LEBT systems with electrostatic quadrupoles (ESQ) and einzel lenses are discussed.

Reiser, M.

1991-05-01

294

Quasi-optical components for MMW fed radars and particle accelerators  

Microsoft Academic Search

In future radars and electron-positron colliders projected to be fed with millimeter waves of high power, electromagnetic flows should be canalized with strongly oversized waveguides or mirror lines. To control such flows, wave beam switches, combiners, multiplexers, pulse compressors, particle acceleration structures and other relevant components should be also quasi-optical.

M. I. Petelin; G. Caryotakis; A. A. Tolkachev; S. V. Kuzikov; G. K. Postoenko; M. L. Tai; A. D. Yunakovsky

1999-01-01

295

Novel Methods in the Particle-In-Cell Accelerator Code-Framework Warp.  

National Technical Information Service (NTIS)

The Particle-In-Cell (PIC) Code-Framework Warp is being developed by the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) to guide the development of accelerators that can deliver beams suitable for high energy density experiments and implo...

A. Friedman D. P. Grote J. L. Vay R. H. Cohen

2011-01-01

296

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

Microsoft Academic Search

When dealing with particle accelerators, especially in systems with travelling wave structures and low beam loading, a substantial amount of RF power is dissipated in 50? termination loads. For the Super Proton Synchrotron (SPS) at Cern this is 69 % of the incident RF power or about 1 MW. Different ideas, making use of that otherwise dissipated power, are presented

Michael Betz; Friedhelm Caspers

2010-01-01

297

The IFMIF-EVEDA accelerator beam dump design  

NASA Astrophysics Data System (ADS)

The IFMIF-EVEDA accelerator will be a 9 MeV, 125 mA cw deuteron accelerator prototype for verifying the validity of the 40 MeV accelerator design for IFMIF. A beam dump designed for maximum power of 1.12 MW will be used to stop the beam at the accelerator exit. The conceptual design for the IFMIF-EVEDA accelerator beam dump is based on a conical beam stop made of OFE copper. The cooling system uses an axial high velocity flow of water pressurized up to 3.4 × 105 Pa to avoid boiling. The design has been shown to be compliant with ASME mechanical design rules under nominal full power conditions. A sensitivity analysis has been performed to take into account the possible margin on the beam properties at the beam dump entrance. This analysis together with the study of the maintenance issues and the mounting and dismounting operations has led to the complete design definition.

Iglesias, D.; Arranz, F.; Arroyo, J. M.; Barrera, G.; Brañas, B.; Casal, N.; García, M.; López, D.; Martínez, J. I.; Mayoral, A.; Ogando, F.; Parro, M.; Oliver, C.; Rapisarda, D.; Sanz, J.; Sauvan, P.; Ibarra, A.

2011-10-01

298

Accelerations in water waves by extended particle image velocimetry  

NASA Astrophysics Data System (ADS)

Particle image velocimetry (PIV) measures instantaneous velocity across an extended area of flow by recording the motion of tracers suspended in and moving with the fluid. This principle is extended to the measurement of higher moments of the velocity field (acceleration) by recording the velocity field at two separate time instants using two cameras, viewing the same region of flow. Planar illumination of large areas within a hydrodynamic flow is achieved using a scanned argon ion laser beam and individual velocity measurements are made by cross-correlating image pairs acquired with a cooled, frame-straddling camera. A high-speed acousto-optic modulator is used to shut off the CW laser after two scans of the flow have been captured by the first camera. The modulator switches the beam back on for the second velocity measurement after a programmed delay. Synchronization of the cameras and beam modulator with the scanning beam system is achieved with a purpose-built multi-channel synchronizer device and operated from an integrated modular tree-based acquisition and processing software system. The extended PIV system is employed to measure the velocities and accelerations in periodic waves in a precise laboratory wave tank. A complementary theoretical description of Stokes waves provides a comparison with the measurements. The theoretical model is very precise, with an error term being less than 0.5% relative to the primary wave for the conditions of the experiments. The purpose is to test the measurement system and to judge the accuracy of the wave experiments under realistic and controllable conditions in the laboratory. Good agreement between the experiments and theory is found. The relative accuracy of the present experiments and measurements may be quantified in terms of the standard deviation due to an ensemble of measurements. In the best case, we find a relative standard deviation of 0.6% for the velocity measurements and 2% for the accelerations. It is indicated that such an accuracy may be generally achieved by appropriately choosing the size of the field of view.

Jensen, A.; Sveen, J. K.; Grue, J.; Richon, J.-B.; Gray, C.

299

Transformer ratio improvement for beam based plasma accelerators  

SciTech Connect

Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R {<=} 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl [University of California, Los Angeles, Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); University of Southern California, Department of Electrical Engineering, Los Angeles, CA 90089 U.S.A. and Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Accelerator Test Facility, Brookhaven National Lab, Upton, NY, 11973 (United States)

2012-12-21

300

Focusing of laser-accelerated proton beams using curved targets, and improved energy deposition  

NASA Astrophysics Data System (ADS)

We use numerical simulations for laser-plasma interaction and particle transport, to study proton acceleration from curved targets and their potential for isochoric heating. Combining a proton dot geometry, to produce a low-energy cut-off in the accelerated proton beam spectrum, and a cylindral shape of the substrate, to bend proton trajectories, we compute increased energy deposition in an auxiliary target placed in the proton beam path, compared to protons that would be accelerated from a flat substrate. The highest temperatures are obtained when placing the auxiliary target slightly after the theoretical focus position, confirming the trend observed in the PIC simulations that cylinders focus slightly after their radius. Moving the target out of the proton beam focus, the peak temperature decreases and a larger transverse region can be heated.

Carrié, Michaël; Lefebvre, Erik

2011-12-01

301

Modeling beam-driven and laser-driven plasma Wakefield accelerators with XOOPIC  

SciTech Connect

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

Bruhwiler, David L.; Giacone, Rodolfo; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, Wim

2000-06-01

302

Toward higher order particle simulation of space-charge-dominated beams  

Microsoft Academic Search

The intense particle beams to be used as drivers for Heavy Ion Inertial Fusion exhibit dynamics which are dominated by space-charge (abbreviated s-c) forces, rather than by thermal pressure (as in most traditional accelerator applications). Such beams are non-neutral plasmas, and the particle-in-cell technique (with the addition of detailed models for the externally applied fields and the domain geometry) has

1998-01-01

303

Theoretical and Experimental Evaluation of Aerodynamic Lenses for Producing Particle Beams of Controlled Dimensions and Divergence.  

NASA Astrophysics Data System (ADS)

A particle beam is produced when a particle-laden gas expands through a nozzle into a vacuum. This work discusses a method of producing very narrow and highly collimated particle beams. The approach is to pass the particle-laden gas through a series of axisymmetric contractions and enlargements (so called aerodynamic lenses) before the nozzle expansion. Particles are confined closely to the axis alter passing through these lenses. Since particles close to the axis experience small radial drag forces, they stay close to the axis during nozzle expansion and therefore form a narrow particle beam downstream. The major effects that limit the minimum beam width are Brownian motion and lift forces on particles during nozzle expansion. Lift -force effects often occur for non-spherical particles and are often greater than Brownian-motion effects. A particle -beam-forming apparatus consisting of a variable number of lenses in series followed by an accelerating nozzle was developed for the application in a Particle Beam Mass Spectrometer (PBMS). This instrument is to measure ultrafine particles (0.01 ~ 0.5 murm m) in low pressure (>= 0.1 torr) environments such as those in semiconductor processing equipment. The experimental evaluations showed that as more lenses were added the particle beam widths were reduced asymptotically to the minimum values. For spherical particles these minimum values are in good agreement with those predicted from a Brownian-motion model. For non-spherical particles these minimum widths are often much larger than the Brownian limit, which is consistent with theoretical predictions based on lift forces. A Low -Pressure Laser Particle Detector (LPLPD) using aerodynamic lenses was also developed and evaluated in this work. Because of its high particle counting efficiencies (~ 100%) and small flow resistance, it is suitable for detecting particles in exhaust lines of semiconductor processing equipment. This work demonstrates that aerodynamic lenses are an effective means for separating particles from a carrier gas and confining them to the centerline of symmetric flows.

Liu, Peng

304

Micro\\/nano-particle electrostatic accelerator for electric propulsion  

Microsoft Academic Search

Summary form only given: The nanoparticle field extraction thruster (NanoFET) is an electrostatic micro\\/nano-particle accelerator technology that is being developed for use as an electric propulsion system. Conceptually, NanoFET employs micro\\/nano-electromechanical systems (MEMS\\/NEMS) to transport, charge, and accelerate conductive particles. The propellant, via piezoelectric actuations, is fed from a storage reservoir through a charging grid that breaks up particle agglomerates.

T. M. Liu; A. D. Gallimore; B. E. Gilchrist; P. Y. Peterson

2009-01-01

305

Design for low beam loss in accelerators for intense neutron source applications  

SciTech Connect

Control of beam loss in intense ion linacs involves keeping beam spill below parts in 10[sup [minus]5]--10[sup [minus]8]/m by preventing total beam size from extending to the limiting apertures. Starting from good rms design practices, new analysis of the machine architecture is described in terms of the effects of the machine tune with space-charge, free-energy constraint, and halo-producing mechanisms. It is shown that halos are produced by the time- (or position-) varying nature of common linac aspects (such as misalignment, mismatching, acceleration, and construction techniques) through collective core/single-particle interaction dynamics plus resonances.

Jameson, R.A.

1993-01-01

306

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

Microsoft Academic Search

The development of ultrahigh vacuum technology for high-energy particle accelerators and magnetic fusion devices provided essential contributions to the progress in these two scientific endeavors over the last four decades. Storage rings were first proposed as an efficient means of producing intense high-energy particle beams by G. K. O'Neill in 1956. The milestone demonstrations of the importance of this invention

H. F. Dylla

1994-01-01

307

Testing general relativity with laser accelerated electron beams  

SciTech Connect

Electron accelerations of the order of 10{sup 21} g obtained by laser fields open up the possibility of experimentally testing one of the cornerstones of general relativity, the weak equivalence principle, which states that the local effects of a gravitational field are indistinguishable from those sensed by a properly accelerated observer in flat space-time. We illustrate how this can be done by solving the Einstein equations in vacuum and integrating the geodesic equations of motion for a uniformly accelerated particle.

Gergely, L. A.; Harko, T. [Department of Theoretical Physics, University of Szeged, Szeged 6720, Tisza L. krt. 84, Hungary and Department of Experimental Physics, University of Szeged, 6720 Szeged, Dom ter 9 (Hungary); Department of Physics and Center for Theoretical and Computational Physics, University of Hong Kong, Pok Fu Lam Road (Hong Kong)

2012-07-09

308

Double-decker femtosecond electron beam accelerator for pulse radiolysis  

NASA Astrophysics Data System (ADS)

A new concept of double-decker electron beam accelerator based on a photocathode radio-frequency (rf) gun was proposed for studying chemical kinetics and primary processes or reactions of radiation chemistry. The synchronized double-decker electron beams with time interval of 1.4 ns were generated in the rf gun by injecting two laser beams on the photocathode. The double-decker electron beams were accelerated by a booster linear accelerator (linac) up to 31.8 MeV with energy-phase correlation and compressed into femtosecond by rotating the bunch in the energy-phase distribution in magnetic fields. The normalized transverse emittance of both beams downstream of the linac was obtained to be 2.5+/-0.6 mm mrad for the up beam with bunch charge of 0.47 nC and 3.6+/-0.7 mm mrad for the down beam with bunch charge of 0.65 nC. The minimum relative energy spread was (0.14+/-0.03)% for the two beams. The compressed bunch length was obtained to be 430+/-25 fs for the up bunch and 510+/-20 fs for the down bunch.

Yang, Jinfeng; Kondoh, Takafumi; Yoshida, Akira; Yoshida, Youichi

2006-04-01

309

Induction accelerators and free-electron lasers at LLNL: Beam Research Program  

SciTech Connect

Linear induction accelerators have been developed to produce pulses of charged particles at voltages exceeding the capabilities of single-stage, diode-type accelerators and at currents too high rf accelerators. In principle, one can accelerate charged particles to arbitrarily high voltages using a multistage induction machine. The advent of magnetic pulse power systems makes sustained operation at high repetition rates practical, and high-average-power capability is very likely to open up many new applications of induction machines. In Part A of this paper, we survey the US induction linac technology, emphasizing electron machines. We also give a simplified description of how induction machines couple energy to the electron beam to illustrate many general issues that designers of high-brightness and high-average-power induction linacs must consider. We give an example of the application of induction accelerator technology to the relativistic klystron, a power source for high-gradient accelerators. In Part B we address the application of LIAs to free-electron lasers. The multikiloampere peak currents available from linear induction accelerators make high-gain, free-electron laser amplifier configurations feasible. High extraction efficiencies in a single mass of the electron beam are possible if the wiggler parameters are appropriately ''tapered'', as recently demonstrated at millimeter wavelengths on the 4-MeV ELF facility. Key issues involved in extending the technology to shorter wavelengths and higher average powers are described. Current FEL experiments at LLNL are discussed. 5 refs., 16 figs.

Briggs, R.J.

1989-02-15

310

Polarization of fast particle beams by collisional pumping  

DOEpatents

The invention relates to method and apparatus for polarizing a fast beam of particles by collisional pumping, including generating a fast beam of particles, and generating a thick electron-spin-polarized medium positioned as a target for said beam, said medium being sufficiently thick to allow said beam to interact with said medium to produce collisional pumping whereby said particle beam becomes highly polarized.

Stearns, J.W.; Kaplan, S.N.; Pyle, R.V.; Anderson, L.W.; Schlachter, A.S.; Ruby, L.

1984-10-19

311

Beam breakup instabilities in high current electron beam racetrack induction accelerators  

SciTech Connect

Beam breakup and negative mass instability growth rates for a 1 kA, 40 MeV electron beam racetrack induction accelerator are computed. The device is taken to have four acceleration gaps, each with 0.2 MeV applied voltage and 15 ohm transverse impedence; the guide field is 2 kg. The authors find that the total amplification of the beam breakup mode is limited to five e-foldings provided that the cavity mode quality factor Q is 6. Thus, the negative mass instability, which grows several times faster, is the dominant consideration. However, they also find that the energy range over which the negative mass instability occurs can be narrowed substantially by reducing the guide field strength after the beam has been accelerated to about 12 MeV. This approach, coupled with beam thermal effects, probably is sufficient to limit negative mass growth to acceptable levels in the racetrack accelerator.

Godfrey, B.B.; Hughes, T.P.

1983-08-01

312

Possibility for ultra-bright electron beam acceleration in dielectric wakefield accelerators  

SciTech Connect

We describe a conceptual proposal to combine the Dielectric Wakefield Accelerator (DWA) with the Emittance Exchanger (EEX) to demonstrate a high-brightness DWA with a gradient of above 100 MV/m and less than 0.1% induced energy spread in the accelerated beam. We currently evaluate the DWA concept as a performance upgrade for the future LANL signature facility MaRIE with the goal of significantly reducing the electron beam energy spread. The preconceptual design for MaRIE is underway at LANL, with the design of the electron linear accelerator being one of the main research goals. Although generally the baseline design needs to be conservative and rely on existing technology, any future upgrade would immediately call for looking into the advanced accelerator concepts capable of boosting the electron beam energy up by a few GeV in a very short distance without degrading the beam's quality. Scoping studies have identified large induced energy spreads as the major cause of beam quality degradation in high-gradient advanced accelerators for free-electron lasers. We describe simulations demonstrating that trapezoidal bunch shapes can be used in a DWA to greatly reduce the induced beam energy spread, and, in doing so, also preserve the beam brightness at levels never previously achieved. This concept has the potential to advance DWA technology to a level that would make it suitable for the upgrades of the proposed Los Alamos MaRIE signature facility.

Simakov, Evgenya I.; Carlsten, Bruce E.; Shchegolkov, Dmitry Yu. [Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545 (United States)

2012-12-21

313

Long pulse H{sup -} ion beam acceleration in MeV accelerator  

SciTech Connect

A multiaperture multigrid accelerator called ''MeV accelerator'' has been developed for neutral beam injection system of international thermonuclear experimental reactor. In the present work, long pulse H{sup -} ion beam acceleration was performed by the MeV accelerator equipped with new water-cooled grids. At present, the pulse length was extended to 5 s for the beams of 750 keV, 221 mA, and 10 s for the beams of 600 keV, 158 mA. Energy density, defined as products of beam energy (keV), current (mA), and pulse (s) divided by aperture area (m{sup 2}), increased more than one order of magnitude higher compared with original MeV accelerator without water cooling in its grids. At higher energy and current, the grid was melted by beam deflection. Due to this grid melting, breakdowns occurred between the grids, and hence, the pulse length was limited. Beam deflection will be compensated by aperture displacement in next experiment.

Taniguchi, M.; Mizuno, T.; Umeda, N.; Kashiwagi, M.; Watanabe, K.; Tobari, H.; Kojima, A.; Tanaka, Y.; Dairaku, M.; Hanada, M.; Sakamoto, K.; Inoue, T. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

2010-02-15

314

Accelerator Based Neutron Beams for Neutron Capture Therapy  

SciTech Connect

The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 10(sup 7) W/m(sup 2) with heat transfer coefficients of 10(sup 6)W/m(sup 2)-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and compared the RBE characteristics of the MIT Reactor M67 clinical beam, The Brookhaven Medical Research Reactor clinical beam (both of which were used in Phase I/II clinical trials of BNCT) and the MIT LABA BNCS beam. Additional research initiated under this program involved an investigation of the potential of BNCT for the prevention of restenosis and the development of accelerator-based fast neutron brachytherapy. A total of 10 student research theses (2 Undergraduate, 4 Masters, and 4 Doctoral) were completed as part of this research program.

Yanch, Jacquelyn C.

2003-04-11

315

Beam transport and monitoring for laser plasma accelerators  

SciTech Connect

The controlled transport and imaging of relativistic electron beams from laser plasma accelerators (LPAs) are critical for their diagnostics and applications. Here we present the design and progress in the implementation of the transport and monitoring system for an undulator based electron beam diagnostic. Miniature permanent-magnet quadrupoles (PMQs) are employed to realize controlled transport of the LPA electron beams, and cavity based electron beam position monitors for non-invasive beam position detection. Also presented is PMQ calibration by using LPA electron beams with broadband energy spectrum. The results show promising performance for both transporting and monitoring. With the proper transport system, XUV-photon spectra from THUNDER will provide the momentum distribution of the electron beam with the resolution above what can be achieved by the magnetic spectrometer currently used in the LOASIS facility.

Nakamura, K.; Sokollik, T.; Tilborg, J. van; Gonsalves, A. J.; Shaw, B.; Shiraishi, S.; Mittal, R.; De Santis, S.; Byrd, J. M.; Leemans, W. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States) and University of California, Berkeley, CA 94720 (United States)

2012-12-21

316

Beam dynamics simulation for the Compact Linear Collider drive-beam accelerator  

NASA Astrophysics Data System (ADS)

In the Compact Linear Collider (CLIC) now being studied at CERN, the rf power which accelerates the main beam is provided by decelerating a high current drive beam. The drive-beam linac has to accelerate a 4.2 A electron beam up to 2.4 GeV in almost fully loaded structures. The pulse contains about 70 000 bunches, one in every second rf bucket, and has a length of 140?s. The beam stability along the beam line is of concern for such a high current and pulse length. We present different options for the lattice of the linac based on FODO, triplet, and doublet cells and compare the transverse instability for each lattice including the effects of beam jitter, alignment, and beam-based correction.

Aksoy, Avni; Schulte, Daniel; Yava?, Ömer

2011-08-01

317

Generalized Skilling Equation for Particle Acceleration in Reconnecting Magnetic Fields  

NASA Astrophysics Data System (ADS)

While particle-in-cell simulations provide valuable information on particle acceleration in two-dimensional reconnection problems, such simulations are much rarer in three dimensions because of the limits of computing power. Hence, analytical approaches to calculating particle distribution functions need to be developed. In recent years, there have been attempts to use variants of Parker's transport equation to particle acceleration problems involving magnetic islands. In this paper, we present the derivation of a generalized Skilling equation (GSE) for guiding-center plasmas that is shown to reduce to Parker's transport equation under some strong assumptions, not generally valid for particle acceleration involving magnetic islands. The GSE assumes gyrotropy, but enables the treatment of anisotropy of the particle distribution function. The equation can be applied to relativistic as well as non-relativistic particles. We will present results on the application of this equation to hydrogen as well as pair plasmas.

Wang, Liang; Bhattacharjee, A.; Lee, M.

2010-11-01

318

High energy particle accelerators that can fit on a (large) tabletop by using lasers  

NASA Astrophysics Data System (ADS)

Accelerators are essential tools of discovery and have many practical uses. At the forefront of accelerator technology are the machines that deliver beams for particle physics, for synchrotron and free electron based radiation sources. The technology that drives these accelerators is extremely sophisticated but is limited by the maximum sustainable accelerating field. This impacts the size and cost of the device. More than two decades ago, lasers were proposed as power source for driving novel accelerators based on plasmas as the accelerating medium. An overview will be presented of what these devices can produce to date, including the 2004 demonstration of high quality electron beams [1] and the 2006 demonstration of GeV class beams from a 3 cm long accelerating structure [2]. We then discuss the key challenges for broad applicability of the technology and our goal of making a laser accelerator driven a VUV/soft x-ray free electron laser. [1] C.G.R. Geddes et al., Nature 431, 538-541 (2004); S.P.D. Mangles et al., ibid 535-538; J. Faure et al., ibid. 541-544. [2] W.P. Leemans et al., Nature Physics 2, 696-699 (2006).

Leemans, Wim

2008-04-01

319

Fibre optic radiation sensor systems for particle accelerators  

NASA Astrophysics Data System (ADS)

Two different fibre optic dosimeter systems based on the radiation-induced increase of fibre attenuation are presented. The systems allow on-line measurement of the accumulated dose along accelerator beam lines (``distributed'' sensor) as well as at fixed positions in selected accelerator sections (local sensors). Fibre properties, system layout and results of measurements obtained during operation of the TESLA Test Facility (TTF) at DESY Hamburg are described. Tera Electron Volt Energy Superconducting Linear Accelerator.

Henschel, H.; Körfer, M.; Kuhnhenn, J.; Weinand, U.; Wulf, F.

2004-07-01

320

Application of particle accelerators in research.  

PubMed

Since the beginning of the past century, accelerators have started to play a fundamental role as powerful tools to discover the world around us, how the universe has evolved since the big bang and to develop fundamental instruments for everyday life. Although more than 15 000 accelerators are operating around the world only a very few of them are dedicated to fundamental research. An overview of the present high energy physics (HEP) accelerator status and prospectives is presented. PMID:21908658

Mazzitelli, Giovanni

2011-07-01

321

Collection and focusing of laser accelerated ion beams for therapy applications  

NASA Astrophysics Data System (ADS)

Experimental results in laser acceleration of protons and ions and theoretical predictions that the currently achieved energies might be raised by factors 5-10 in the next few years have stimulated research exploring this new technology for oncology as a compact alternative to conventional synchrotron based accelerator technology. The emphasis of this paper is on collection and focusing of the laser produced particles by using simulation data from a specific laser acceleration model. We present a scaling law for the “chromatic emittance” of the collector—here assumed as a solenoid lens—and apply it to the particle energy and angular spectra of the simulation output. For a 10 Hz laser system we find that particle collection by a solenoid magnet well satisfies requirements of intensity and beam quality as needed for depth scanning irradiation. This includes a sufficiently large safety margin for intensity, whereas a scheme without collection—by using mere aperture collimation—hardly reaches the needed intensities.

Hofmann, Ingo; Meyer-Ter-Vehn, Jürgen; Yan, Xueqing; Orzhekhovskaya, Anna; Yaramyshev, Stepan

2011-03-01

322

Accelerator systems and instrumentation for the NuMI neutrino beam  

NASA Astrophysics Data System (ADS)

The Neutrinos at the Main Injector (NuMI) neutrino beam facility began operating at the Fermi National Accelerator Laboratory in 2005. NuMI produces an intense, muon-neutrino beam to a number of experiments. Fore most of these experiments is MINOS---the Main Injector Neutrino Oscillation Search---that uses two neutrino detectors in the beam, one at Fermilab and one in northern Minnesota, to investigate the phenomenon of neutrino oscillations. NuMI is a conventional, horn-focused neutrino beam. It is designed to accept a 400 kW, 120 GeV proton beam from the Fermilab Main Injector accelerator. The proton beam is steered onto a target, producing a secondary beam of mesons which are focused into a long evacuated volume where they decay to muons and neutrinos. Pulsed toroidal magnets (horns) focus an adjustable meson momentum range. Design of the beamline and its components is challenged by the 400 kW average proton beam power. To achieve such high proton power, the Fermilab Main Injector (MI) must store and accelerate ˜ 4x1013 protons per acceleration cycle. This requires the MI to be loaded with 6 or more batches of protons from the 8 GeV Booster accelerator. Such multiple-batch injection involves a synchronization of the two machines not previously required by the Fermilab accelerators. In this dissertation, we investigate timing errors that can arise between the two accelerators, and a feedback system which enables multiple Booster transfers into the Main Injector without significant loss of beam. Using this method of synchronous transfer, the Main Injector has delivered as many as 3x1013 protons per pulse to the NuMI beam. The instrumentation to assess the quality of the neutrino beam includes arrays of radiation-tolerant ionization chambers downstream of the decay volume. These arrays detect the remnant hadrons and tertiary muons produced with the neutrinos. This thesis discusses measurements using the arrays, including diagnostics of potential beam errors and initial alignment of the beamline elements. In addition, we describe theoretical calculations and experimental tests which demonstrate that the ionization chambers can withstand the intense particle fluxes in the beamline without signal loss due to space-charge build up in the detectors.

Zwaska, Robert Miles

323

Dynamics of accelerated electron beams and X rays in solar flares with sub-THz radiation  

NASA Astrophysics Data System (ADS)

Unique measurements by a solar submillimeter radio telescope (SST) have been carried out in the sub-THz radiation at 212 and 405 THz over the past decade. The spectrum of RF radiation in this region increased with frequency for the three flares of November 2 and 4, 2003, and December 6, 2006, and the flux value reached 5 × 103-2 × 104 sfu at 405 GHz (Kaufman et al., 2009). In this work, we consider a set of nonlinear equations for an accelerated electrons beam and the Langmuir wave energy density. The distribution functions of the accelerated electron beam and wave energy density are calculated taking into account Coulomb collisions, electron scattering by waves, and wave scattering by plasma ions. In addition, the source of accelerated particles and the heat level of the Langmuir turbulence are specified. The beam and plasma parameters are chosen based on the aims of a problem. The plasma concentration varies from n = 1013 to 1015 cm-3, the electron plasma frequency f p = (3 × 1010-3 × 1011) Hz in this case. The ratio of plasma and beam concentrations, sufficient to explain the value of the radio flux at a frequency of 300 GHz, is n b/ n = 10-3. The Langmuir turbulence is excited due to the instability of the accelerated electron beam with an initial distribution function of the "bump-in-tail" type. Then, the parameters of radiowaves are calculated in the sub-THz range under the assumption of coalescence of two plasma waves. The calculation results show that a sub-THz radio flux can be obtained under the condition of injection of accelerated electrons. The fine time structure of radio flux observed is easily simulated based on this statement by the pulsed time structure of electron beams and their dynamics in overdense plasma. X-ray and gamma radiation was recorded during the events under study. Hard X-ray radiation is bremsstrahlung radiation from accelerated electron beams.

Vatagin, P. V.; Charikov, Yu. E.; Stepanov, A. V.; Kudryavtsev, I. V.

2012-12-01

324

Simulation of particle acceleration in the PLASMONX project  

SciTech Connect

In this paper I will present some numerical studies and parameter scans performed with the electromagnetic, rela-tivistic, fully-self consistent particle-in-cell (PIC) code ALaDyn (Acceleration by LAser and DYNamics of charged particles), concerning electron acceleration via plasma waves in the framework of the INFN-PLASMONX (PLASma acceleration and MONochromatic X-ray production) project. In particular I will focus on the modelling of the SITE (Self Injection Test Experiment) which will be a relevant part of the commissioning of the FLAME laser. Some issues related to the quality of the accelerated bunch will be discussed.

Benedetti, Carlo [Dep. of Physics, University of Bologna and INFN/Bologna, Via Irnerio 46, 40126, Bologna (Italy)

2010-02-02

325

Deflective focusing system for charged particle beam  

SciTech Connect

A deflective focusing system includes a magnetic lens for focusing a charged particle beam, a plurality of rings made of magnetic material arranged substantially concentrically with the magnetic lens inside of the magnetic lens, the rings being arranged at spaced apart positions in the direction of the central axis of the magnetic lens so as to form a predetermined magnetic focusing field distribution, a one-stage electrostatic deflector having a plurality of deflection electrodes which are spaced apart in a circumferential direction of the magnetic lens, which are arranged substantially concentrically with the magnetic lens inside of the magnetic lens, and which extend in the direction of the central axis so as to form a predetermined electrostatic deflection field distribution, so that the charged particle beam passes through the concentrically arranged deflection electrodes to be deflected in accordance with a voltage applied to the deflection electrodes, and ring-like grounding electrodes disposed substantially concentrically with the magnetic lens on the object plane side and the image plane side of the electrostatic deflector along the passage of the charged particle beam. The electromagnetic field is adjusted by the deflector, the rings and the grounding electrodes to obtain small aberrations and a small landing angle.

Morita, H.; Hosokawa, T.

1985-06-25

326

Plasma flow and fast particles in a hypervelocity accelerator: a color presentation.  

PubMed

A new concept for particle acceleration for micrometeoroid simulation was developed at NASA Marshall Space Flight Center, using a high-density self-luminescent fast plasma flow to accelerate glass beads (with a diameter up to 1.0 mm) to velocities between 15-20 km/sec. After a short introduction to the operation of the hypervelocity range, the eight-converter-camera unit used for the photographs of the plasma flow and the accelerated particles is described. These photographs are obtained with an eight-segment reflecting pyramidal beam splitter. Wratten filters were mounted between the beam splitter and the converter tubes of the cameras. The photographs, which were recorded on black and white film, were used to make the matrices for the dye-color process, which produced the prints shown. PMID:20155054

Igenbergs, E B; Cour-Palais, B; Fisher, E; Stehle, O

1975-10-01

327

H-mode Accelerating Structures with PMQ Focusing for Low-Beta Beams  

SciTech Connect

We report on results of the project developing high-efficiency normal-conducting RF accelerating structures based on inter-digital H-mode (IH) cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of IH-PMQ structures is 10-20 times higher than that of a conventional drift-tube linac, while the transverse size is 4-5 times smaller. The H-PMQ accelerating structures following a short RFQ can be used both in the front end of ion linacs or in stand-alone applications. Results of the combined 3-D modeling -- electromagnetic computations, beam-dynamics simulations with high currents, and thermal-stress analysis -- for a full IH-PMQ accelerator tank are presented. The accelerating field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of EM and beamdynamics modeling. Multi-particle simulations withParmela and CST Particle Studio have been used to confirm the design. Measurement results of a cold model of the IH-PMQ tank are presented.

Kurennoy, Sergey S. [Los Alamos National Laboratory; O'Hara, James F. [Los Alamos National Laboratory; Olivas, Eric R. [Los Alamos National Laboratory; Rybarcyk, Lawrence J. [Los Alamos National Laboratory

2011-01-01

328

GeV electron beams from a cm-scale accelerator  

SciTech Connect

GeV electron accelerators are essential to synchrotron radiation facilities and free electron lasers, and as modules for high-energy particle physics. Radio frequency based accelerators are limited to relatively low accelerating fields (10-50 MV/m) and hence require tens to hundreds of meters to reach the multi-GeV beam energies needed to drive radiation sources, and many kilometers to generate particle energies of interest to the frontiers of high-energy physics.Laser wakefield accelerators (LWFA) in which particles are accelerated by the field of a plasma wave driven by an intense laser pulse produce electric fields several orders of magnitude stronger (10-100 GV/m) and so offer the potential of very compact devices. However, until now it has not been possible to maintain the required laser intensity, and hence acceleration, over the several centimeters needed to reach GeV energies.For this reason laser-driven accelerators have to date been limited to the 100 MeV scale. Contrary to predictions that PW-class lasers would be needed to reach GeV energies, here we demonstrate production of a high-quality electron beam with 1 GeV energy by channeling a 40 TW peak power laser pulse in a 3.3 cm long gas-filled capillary discharge waveguide. We anticipate that laser-plasma accelerators based on capillary discharge waveguides will have a major impact on the development of future femtosecond radiation sources such as x-ray free electron lasers and become a standard building block for next generation high-energy accelerators.

Leemans, W.P.; Nagler, B.; Gonsalves, A.J.; Toth, C.; Nakamura,K.; Geddes, C.G.R.; Esarey, E.B.; Schroeder, C.; Hooker, S.M.

2006-05-04

329

The Proceedings of Joint 28th ICFA Advanced Beam Dynamics and Advanced Nova Accelerator Workshops on Quantum Aspects of Beam Physics  

SciTech Connect

The Joint 28th ICFA (International Committee for Future Accelerators) Advanced Beam Dynamics and Advanced and Novel Accelerators Workshop on ''QUANTUM ASPECTS OF BEAM PHYSICS and Other Critical Issues of Beams in Physics and Astrophysics'', was held on January 7-11, 2003, in Hiroshima, Japan. This was the third in the QABP workshop series. The first QABP workshop was launched in January 1998, in Monterey, California, and the second was held in October 2000, in Capri, Italy. Over the past five years, this workshop series has passed its torch around the world, from the U.S. to Europe, and this time to Japan in Asia. Following the footsteps of the first two workshops, this one in Hiroshima was again a tremendous success. The frontier of beam research points to increasingly higher energy, greater brightness and lower emittance beams with ever-increasing particle species. These demands have triggered a rapidly growing number of beam phenomena that involve quantum effects. With the significant advancement of laser and accelerator technologies, there is also a growing interest in using high energy, high intensity particle and photon beams for laboratory astrophysics investigations, as well as the application of beam physics expertise to astrophysics studies. It has therefore become a tradition that this workshop series attracted a broad spectrum of experts from beam physics, astrophysics, cosmology, particle physics, condensed matter physics, nuclear physics, atomic physics, and laser science, to explore a common frontier where their individual expertise and interests overlapped.

Chen, P

2004-04-20

330

Two-beam, Multi-mode Detuned Accelerating Structure  

SciTech Connect

A two-beam accelerator structure is described having several novel features including all metal construction, no transfer structures required between the drive and accelerator channels, symmetric fields at the axes of each channel, RF micropulse widths on cavity irises that are less than half those for a conventional cavity at the same fundamental frequency by virtue of using several harmonically-related cavity modes, and a transformer ratio much greater than unity by the use of detuned cavities. Detuning is also shown to allow either parallel or anti-parallel directions for the drive and accelerated beams. A preliminary calculation for the dilution of emittance due to short-range wakes for drive beam parameters similar to those for CLIC shows this effect to be acceptably small.

Kazakov, S. Yu. [Omega-P, Inc., 199 Whitney Ave., Suite 200, New Haven, CT 06511 (United States); High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba-shi, Ibaraki, 305-0801 (Japan); Kuzikov, S. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod Russia (Russian Federation); Yakovlev, V. P. [Omega-P, Inc., 199 Whitney Ave., Suite 200, New Haven, CT 06511 (United States); Fermi national Accelerator Laboratory, Batavia, IL 60510 (United States); Hirshfield, J. L. [Omega-P, Inc., 199 Whitney Ave., Suite 200, New Haven, CT 06511 (United States); Beam Physics Laboratory, Yale University, 272 Whitney Avenue, New Haven, CT 06511 (United States)

2009-01-22

331

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

SciTech Connect

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

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

2001-10-01

332

Using Nonlinear RF Acceleration for FEL Beam Conditioning  

SciTech Connect

We consider a new approach to condition an electron beam using nonlinear effects in the RF field. We demonstrate that such effects can generate a desirable--for the FEL interaction--radial variation of the particle's energy in the beam, and calculate the induced energy spread in the limit of weak field.

Stupakov, G.; Huang, Z.; /SLAC

2005-12-14

333

Femtosecond Microbunched Electron Beam - A New Tool for Advanced Accelerator Research  

SciTech Connect

We employed periodic trains of femtosecond electron bunches for testing several novel concepts of acceleration. A microwave-driven linac sends a 45-MeV electron beam (e-beam) through a magnetic wiggler wherein the e-beam energy is modulated via the inverse free electron laser (IFEL) technique by interacting with a 30-GW CO2 laser beam, so creating 3 fs long microbunches separated by a 30 fs laser period. We show several examples of utilizing such a femtosecond bunch train in advanced accelerator and radiation source research. We demonstrated that microbunching improves the performance of the laser acceleration process compared to the previously investigated single-bunch technique. Specifically, microbunches were phased to the electromagnetic wave of the CO2 laser beam inside a matched tapered wiggler where {approx}80% of electrons gained energy as an ensemble while maintaining a narrow energy spread (i.e., monoenergetic). Another plasma wakefield acceleration (PWFA) experiment explored resonant wakefield excitation in an electric discharge plasma with the plasma frequency matched to that of the CO2 laser. Simulations predict orders-of-magnitude enhancement in the wakefield's amplitude compared with that attained with single bunches. In the Particle Acceleration by Stimulated Emission of Radiation (PASER) experiment, we tested a prediction that an active laser medium can produce particle acceleration by stimulating the emission of radiation. The process benefits from the action of a periodic train of microbunches resonating with the laser transition. Finally, we analyze prospects for using partially coherent x-ray sources based on Thomson backscattering from the electron microbunch train.

Pogorelsky, I. V.; Babzien, M.; Ben-Zvi, I.; Kusche, K. P.; Pavlishin, I. V.; Yakimenko, V.; Dilley, C. E.; Gottschalk, S. C.; Kimura, W. D.; Steinhauer, L. C.; Kallos, E.; Katsouleas, T.; Muggli, P.; Zigler, A.; Banna, S.; Schaechter, L.; Cline, D. B.; Zhou, F.; Kamiya, Y.; Kumita, T. [Brookhaven National Laboratory, Accelerator Test Facility, Upton, NY (United States); STI Optronics Inc., Bellevue, WA (United States); University of Southern California, Los Angeles, CA (United States); Hebrew University, Jerusalem (Israel); Technion - Israel Institute of Technology, Haifa (Israel); University of California at Los Angeles, Los Angeles, CA (United States); Tokyo Metropolitan University, Tokyo (Japan)

2006-04-07

334

Acceleration modification of near-wall turbulence by heavy particles  

NASA Astrophysics Data System (ADS)

By conducting direct numerical simulation combined with Lagrangian particle tracking, we examine modifications of the near-wall turbulence by heavy particles. For simplicity, only spherical and rigid particles are considered in our study and particles are idealized as point-sources in our spectral simulation of turbulent channel flow laden with heavy particles. To assess the effect of particles on the flow field, we use the Particle-Source In Cell (PSIC) model proposed by Crowe et al (1977). Because particles suspended in wall-bounded turbulence can modify the near-wall turbulent structures depending on Stokes number, and these structures are associated with the intermittent, strong acceleration of fluid, particles are expected to modify the turbulence acceleration statistics in the near-wall region. Therefore, in the present study, we especially focus on the modification of the acceleration statistics of turbulence by particles in turbulent channel flow for various Stokes numbers. Detailed statistical changes of acceleration of turbulence by particles and plausible physical explanations will be presented in the meeting.

Lee, Junghoon; Lee, Changhoon

2011-11-01

335

Solar particle acceleration at reconnecting 3D null points  

NASA Astrophysics Data System (ADS)

Context. The strong electric fields associated with magnetic reconnection in solar flares are a plausible mechanism to accelerate populations of high energy, non-thermal particles. One such reconnection scenario, in a fully 3D geometry, occurs at a magnetic null point. Here, global plasma motion can give rise to strong currents in the spine axis or fan plane. Aims: We aim to understand the mechanism of charged particle energy gain in both the external drift region and the diffusion region associated with 3D magnetic reconnection. In doing so we aim to evaluate the efficiency of resistive spine and fan models for particle acceleration, and find possible observables for each. Methods: We used a full orbit test particle approach to study proton trajectories within electromagnetic fields that are exact solutions to the steady and incompressible magnetohydrodynamic equations. We studied the acceleration physics of single particle trajectories and found energy spectra from many particle simulations. The scaling properties of the accelerated particles with respect to field and plasma parameters was investigated. Results: For fan reconnection, strong non-uniform electric drift streamlines can accelerate the bulk of the test particles. The highest energy gain is for particles that enter the current sheet, where an increasing "guide field" stabilises particles against ejection. The energy is only limited by the total electric potential energy difference across the fan current sheet. The spine model has both slow external electric drift speed and weak energy gain for particles reaching the current sheet. Conclusions: The electromagnetic fields of fan reconnection can accelerate protons to the high energies observed in solar flares, gaining up to 0.1 GeV for anomalous values of resistivity. However, the spine model, which gave a harder energy spectrum in the ideal case, is not an efficient accelerator after pressure constraints in the resistive model are included.

Stanier, A.; Browning, P.; Dalla, S.

2012-06-01

336

Production of an Accelerated Oxygen-14 Beam.  

National Technical Information Service (NTIS)

BEARS is an ongoing project to provide a light-ion radioactive-beam capability at the 88-Inch Cyclotron at LBNL. Light radioactive isotopes are produced at a 10 MeV proton medical cyclotron, transported 350 m via a high-speed gas transport capillary, cryo...

J. Powell J. P. Neil J. Cerny

2002-01-01

337

Confined alpha particle diagnostic system using an energetic He{sup 0} beam for ITER  

SciTech Connect

The beam neutralization system for measurement of the spatial and velocity distributions of alpha particles of ITER plasmas was studied. As forward angle detection against the beam injection direction is required for effective neutralization, arrangement of the measurement system using possible ports in ITER configuration is proposed. The count rate of neutralized alpha particles produced by the double charge exchange interaction with energetic He{sup 0} beam particles injected is estimated. The ratios of signal to neutron-induced noise are evaluated. When a He{sup 0} beam produced by autodetachment from a 1-1.5 MeV He{sup -} beam of 10 mA is injected, the signal to noise ratio becomes greater than 1 at {rho}<0.4, even without beam modulation. Usage of a lock-in technique at the frequency of radio-frequency quadrapole accelerator will make measurement at the outer region possible.

Sasao, M.; Shinto, K.; Isobe, M.; Nishiura, M.; Kaneko, O.; Wada, M.; Walker, C. I.; Kitajima, S.; Okamoto, A.; Sugawara, H.; Takeuchi, S.; Tanaka, N.; Aoyama, H.; Kisaki, M. [Tohoku University, Aoba, Sendai 980-8579 (Japan); National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); ITER Joint Work Site, Cadarache, 13108 Saint-Paul-lez-Durance cedex (France); Tohoku University, Aoba, Sendai 980-8579 (Japan)

2006-10-15

338

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

SciTech Connect

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 behavior of longitudinal and transverse coupling impendances, 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.

Dragt, A.J.; Gluckstern, R.L.

1990-11-01

339

Development of a Compact Rotating-Wave Electron Beam Accelerator  

Microsoft Academic Search

We present the successful prototype development results of a novel compact rotating-wave electron beam accelerator (RWA). The RWA uses a single cylindrical cavity holding a transverse-magnetic resonant mode in combination with an axial static magnetic field to accelerate electrons to higher energies. With approximately 80 kilowatts of microwave power fed into a C-band cavity, we have been able to successfully

Jose E. Velazco; Peter H. Ceperley

2003-01-01

340

Acceleration Test of Radioactive Nuclear Beam at INS  

NASA Astrophysics Data System (ADS)

An ISOL based radioactive-beam facility has been constructed at INS. The purpose of this facility is to study various technical problems of the Exotic Nuclear Arena in the Japanese Hadron Project(JHP) and to perform experiments of astrophysical interest. Unstable nuclei produced by bombarding a thick target with 30-40 MeV protons or light-ions from the existing SF cyclotron are ionized in ISOL ion sources (ECR, Surface Ionization, Plasma), mass analyzed by an ISOL (M/? M <= 9000), and injected to the following accelerator complex through a 60m long beam transport line. The accelerator complex consists of a Split Coaxial RFQ(172keV/u), and an Interdigital-H linac(1MeV/u) and a matching section between these linacs. At the end of last year, we tried to accelerate stable ^20Ne^2+ beam from the ISOL ion source in order to check the whole system in this facility. The beam was successfully accelerated and transported at the target position placed downstream from the IH linac. First acceleration of unstable nuclei is scheduled in this spring. These results are reported in this paper.

Tomizawa, M.; Arai, S.; Arakaki, Y.; Hashimoto, Y.; Imanishi, A.; Jeong, S. C.; Katayama, I.; Katayama, T.; Kawakami, H.; Kubono, S.; Miyachi, T.; Miyatake, H.; Niki, K.; Nomura, T.; Okada, M.; Oyaizu, M.; Shirakabe, Y.; Strasser, P.; Takeda, Y.; Tanaka, J.; Tanaka, M. H.; Tojyo, E.; Wada, M.

1997-05-01

341

Monoenergetic Proton Beams Accelerated by a Radiation Pressure Driven Shock  

SciTech Connect

We report on the acceleration of impurity-free quasimononenergetic proton beams from an initially gaseous hydrogen target driven by an intense infrared ({lambda} = 10 {micro}m) laser. The front surface of the target was observed by optical probing to be driven forward by the radiation pressure of the laser. A proton beam of MeV energy was simultaneously recorded with narrow energy spread ({sigma}-4%), low normalized emittance (-8 nm), and negligible background. The scaling of proton energy with the ratio of intensity over density (I/n) confirms that the acceleration is due to the radiation pressure driven shock.

Palmer, C.A.; Pogorelsky, I.; Dover, N.P.; Babzien, M.; Dudnikova, G.I.; Ispiriyan, M.; Polyanskiy, M.N.; Schreiber, J.; Shkolnikov, P.; Yakimenko, V.; Najmudin, Z.

2011-11-01

342

Beam dynamics studies for the relativistic klystron two-beam accelerator experiment  

NASA Astrophysics Data System (ADS)

Two-beam accelerators (TBAs) have been proposed as efficient power sources for next generation high-energy linear colliders. Studies have demonstrated the possibility of building TBAs from X-band \\(~8-12 GHz\\) through Ka-band \\(~30-35 GHz\\) frequency regions. The relativistic klystron two-beam accelerator project, whose aim is to study TBAs based upon extended relativistic klystrons, is described, and a new simulation code is used to design the latter portions of the experiment. Detailed, self-consistent calculations of the beam dynamics and of the rf cavity output are presented and discussed together with a beam line design that will generate nearly 1.2 GW of power from 40 rf cavities over a 10 m distance. The simulations show that beam current losses are acceptable and that longitudinal and transverse focusing techniques are sufficiently capable of maintaining a high degree of beam quality along the entire beam line.

Lidia, Steven M.

2001-04-01

343

Gamma-ray generation using laser-accelerated electron beam  

NASA Astrophysics Data System (ADS)

A compact gamma-ray source using laser-accelerated electron beam is being under development at KAERI for nuclear applications, such as, radiography, nuclear activation, photonuclear reaction, and so on. One of two different schemes, Bremsstrahlung radiation and Compton backscattering, may be selected depending on the required specification of photons and/or the energy of electron beams. Compton backscattered gamma-ray source is tunable and quasimonochromatic and requires electron beams with its energy of higher than 100 MeV to produced MeV photons. Bremsstrahlung radiation can generate high energy photons with 20 - 30 MeV electron beams, but its spectrum is continuous. As we know, laser accelerators are good for compact size due to localized shielding at the expense of low average flux, while linear RF accelerators are good for high average flux. We present the design issues for a compact gamma-ray source at KAERI, via either Bremsstrahlung radiation or Compton backscattering, using laser accelerated electron beams for the potential nuclear applications.

Park, Seong Hee; Lee, Ho-Hyung; Lee, Kitae; Cha, Yong-Ho; Lee, Ji-Young; Kim, Kyung-Nam; Jeong, Young Uk

2011-05-01

344

An MCNP-based model of a linear accelerator x-ray beam.  

PubMed

The Monte Carlo N-Particle radiation transport computer code (MCNP) has been employed on a personal computer to develop a simple model simulating the major components within the beam path of a linear accelerator radiation head, namely the electron target, primary conical collimator, beam flattening filter, wedge filter and the secondary collimators. The model was initially used to calculate the energy spectra and angular distributions of the x-ray beam for the Philips SL 75/5 linear accelerator, in a plane immediately beneath the flattening filter. These data were subsequently used as a 'source' of x-rays at the target position, to assess the emergent beam from the secondary collimators. The depth dose distributions and dose profiles at constant depth for various field sizes have been calculated for a nominal operating potential of 4 MV and found to be within acceptable limits. It is concluded that the technique may be used to calculate the energy spectra of any linear accelerator upon specification of the component dimensions, materials and nominal accelerating potential. It is anticipated that this work will serve as the basis of a quality control tool for linear accelerators and treatment planning systems. PMID:10368014

Lewis, R D; Ryde, S J; Hancock, D A; Evans, C J

1999-05-01

345

Magnetic-field generation and particle acceleration in relativistic shear layers  

NASA Astrophysics Data System (ADS)

Both observational evidence and theoretical considerations suggest that the relativistic jets of AGN and GRBs are likely to be cylindrically stratified with a fast, inner spine and a slower, outer sheath. The resulting relativistic shear layer is expected to be a site of self-generation of magnetic fields due to the Weibel instability, and of relativistic particle acceleration. We here present first results of particle-in-cell (PIC) simulations of relativistic shear layers in both electron-proton and electron-positron jets. We demonstrate that magnetic fields close to equipartition can be self-generated in initially unmagnetized flows, and strong electric fields and MHD turbulence in the shear layer lead to the acceleration of highly anisotropic particle distributions. The resulting highly beamed synchrotron and Compton emission, in addition to beaming due to the bulk motion of the plasma, may offer a solution to the Lorentz factor crisis for AGN jets.

Böttcher, Markus; Liang, Edison P.; Smith, Ian A.; Roustazadeh, Parisa

2012-12-01

346

Optimization and beam control in large-emittance accelerators: Neutrino factories;  

SciTech Connect

Schemes for intense sources of high-energy muons require collection, rf capture, and transport of particle beams with unprecedented emittances, both longitudinally and transversely. These large emittances must be reduced or ''cooled'' both in size and in energy spread before the muons can be efficiently accelerated. Therefore, formation of muon beams sufficiently intense to drive a Neutrino Factory or Muon Collider requires multi-stage preparation. Further, because of the large beam phase space which must be successfully controlled, accelerated, and transported, the major stages that comprise such a facility: proton driver, production, capture, phase rotation, cooling, acceleration, and storage are complex and strongly interlinked. Each of the stages must be consecutively matched and simultaneously optimized with upstream and downstream systems, meeting challenges not only technically in the optics and component design, but also in the modeling of both new and extended components. One design for transverse cooling, for example, employs meter-diameter solenoids to maintain strong focusing--300-500 mr beam divergences--across ultra-large momentum ranges, {ge} {+-}20% {delta}p/p, defying conventional approximations to the dynamics and field representation. To now, the interplay of the different systems and staging strategies has not been formally addressed. This work discusses two basic, but different approaches to a Neutrino Factory and how the staging strategy depends on beam parameters and method of acceleration.

Carol Johnstone

2004-08-23

347

Seventy Five Years of Particle Accelerators (LBNL Summer Lecture Series)  

SciTech Connect

Summer Lecture Series 2006: Andy Sessler, Berkeley Lab director from 1973 to 1980, sheds light on the Lab's nearly eight-decade history of inventing and refining particle accelerators, which continue to illuminate the nature of the universe.

Sessler, Andy

2006-07-26

348

Recommendations for the Safe Operation of Particle Accelerators.  

National Technical Information Service (NTIS)

The report gives recommendations pertaining to the basic administration and minimum procedures that should be followed at particle accelerator facilities to insure safe operation. The recommendations are designed to supplement existing regulations and sta...

R. F. Boggs W. E. Gundaker

1968-01-01

349

Production and acceleration of ion beams by laser ablation  

SciTech Connect

In this work, we present a new pulsed laser ablation technique to obtain energetic ion beams. The accelerator we made is a compact device able to extract and accelerate the ionic components of plasma up to 160 keV per charge state. It is composed by a generating chamber containing an expansion chamber used like first electrode. Next, a second electrode connected to ground and a third electrode connected to negative voltage are used. The third electrode is used also as Faraday cup. By the analysis of the ion signals we studied the plume parameters such as TOF accelerated signals, charge state, and divergence.

Velardi, L.; Siciliano, M. V.; Delle Side, D.; Nassisi, V. [Department of Physics and I.N.F.N., LEAS Laboratory, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce (Italy)

2012-02-15

350

Simulations of beam dynamics in the CTF2 drive beam accelerator and bunch compressor  

Microsoft Academic Search

The purpose of this study is to simulate and to have a better understanding of the experimental limitation of the transmission in the CTF2 drive beam in function of the beam charge. In this note, the low energy part of the beam line is studied with the particle-tracking program PARMELA from the gun to the first 30 GHz section. Assuming

M Cayla-Chanudet

2000-01-01

351

Particle Acceleration at High-gamma Shock Waves  

Microsoft Academic Search

First-order Fermi acceleration processes at ultrarelativistic (gamma ~ 5-30) shocks are studied with the method of Monte Carlo simulations. The accelerated particle spectra are obtained by integrating the exact particle trajectories in a turbulent magnetic field near the shock. The magnetic field model assumes finite-amplitude perturbations within a wide wavevector range and with a predefined wave power spectrum, which are

Jacek Niemiec

2005-01-01

352

First-order Fermi particle acceleration by relativistic shocks  

Microsoft Academic Search

Monte Carlo calculations of test particle spectra and acceleration times are presented from first-order Fermi particle acceleration for parallel shocks with arbitrary flow velocities and compression ratios r up to seven, shock velocities u1 up to 0.98c, and injection energies ranging from thermal to highly superthermal. Far above the injection energy, the spectra are well-approximated by a power law and

Donald C. Ellison; Stephen P. Reynolds; Frank C. Jones

1990-01-01

353

Acceleration and Trapping of Particles by Radiation Pressure  

Microsoft Academic Search

Micron-sized particles have been accelerated and trapped in stable optical potential wells using only the force of radiation pressure from a continuous laser. It is hypothesized that similar accelerations and trapping are possible with atoms and molecules using laser light tuned to specific optical transitions. The implications for isotope separation and other applications of physical interest are discussed.

A. Ashkin

1970-01-01

354

Injector and beam transport simulation study of proton dielectric wall accelerator  

NASA Astrophysics Data System (ADS)

A simulation study of a short-pulsed proton injector for, and beam transport in, a dielectric wall accelerator (DWA) has been carried out using the particle-in-cell (PIC) code Warp. It was shown that applying "tilt pulse" voltage waveforms on three electrodes enables the production of a shorter bunch by the injector. The fields in the DWA beam tube were simulated using Computer Simulation Technology's Microwave Studio (CST MWS) package, with various choices for the boundary conditions. For acceleration in the DWA, the beam transport was simulated with Warp, using applied fields obtained by running CST MWS. Our simulations showed that the electric field at the entrance to the DWA represents a challenging issue for the beam transport. We thus simulated a configuration with a mesh at the entrance of the DWA, intended to improve the entrance field. In these latter simulations, a proton bunch was successfully accelerated from 130 keV to about 36 MeV in a DWA with a length of 36.75 cm. As the beam bunch progresses, its transverse dimensions diminish from (roughly) 0.5×0.5 cm to 0.2×0.4 cm. The beam pulse lengthens from 1 cm to 2 cm due to lack of longitudinal compression fields.

Zhao, Quantang; Yuan, P.; Zhang, Z. M.; Cao, S. C.; Shen, X. K.; Jing, Y.; Ma, Y. Y.; Yu, C. S.; Li, Z. P.; Liu, M.; Xiao, R. Q.; Zhao, H. W.

2012-12-01

355

Relativistic electron beam acceleration by nonlinear Landau damping of electrostatic waves in a magnetized plasma  

SciTech Connect

Acceleration and heating of a relativistic electron beam due to nonlinear electron Landau and cyclotron damping of electrostatic waves in a magnetized plasma are investigated theoretically and numerically on the basis of the relativistic kinetic wave and transport equations derived from the relativistic Vlasov-Maxwell equations. Two electrostatic waves interact nonlinearly with the relativistic electron beam satisfying the resonance condition for nonlinear electron Landau and cyclotron damping of {omega}{sub k}-{omega}{sub k{sup '}}-(k{sub perpendicular}-k{sub perpendicula=} r{sup '})v{sub d}-(k{sub parallel}-k{sub parallel}{sup '})v{sub b}{approx_equal}m{omega}{sub ce} where v{sub b} and v{sub d} are the parallel and perpendicular velocities of the relativistic electron beam, respectively, and {omega}{sub ce} is the relativistic electron cyclotron frequency. The beat waves produced by two electrostatic waves resonate with the relativistic electron beam. The relativistic transport equations using the relativistic drifted Maxwellian momentum distribution function of the relativistic electron beam were derived and analyzed. They show obviously its acceleration and heating (deceleration or cooling). Nonlinear electron Landau damping of the two lower-hybrid waves has been studied by the numerical analysis of relativistic nonlinear wave-particle coupling coefficients and it was clarified that the highly relativistic electron beam can be accelerated efficiently via the Compton scattering due to nonlinear electron Landau damping of the lower-hybrid waves.

Sugaya, R. [Department of Physics, Faculty of Science, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)

2004-12-01

356

STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING  

SciTech Connect

The origin of hard X-ray (HXR) excess emission from clusters of galaxies is still an enigma, whose nature is debated. One of the possible mechanisms to produce this emission is the bremsstrahlung model. However, previous analytical and numerical calculations showed that in this case the intracluster plasma had to be overheated very fast because suprathermal electrons emitting the HXR excess lose their energy mainly by Coulomb losses, i.e., they heat the background plasma. It was concluded also from these investigations that it is problematic to produce emitting electrons from a background plasma by stochastic (Fermi) acceleration because the energy supplied by external sources in the form of Fermi acceleration is quickly absorbed by the background plasma. In other words, the Fermi acceleration is ineffective for particle acceleration. We revisited this problem and found that at some parameter of acceleration the rate of plasma heating is rather low and the acceleration tails of nonthermal particles can be generated and exist for a long time while the plasma temperature is almost constant. We showed also that for some regime of acceleration the plasma cools down instead of being heated up, even though external sources (in the form of external acceleration) supply energy to the system. The reason is that the acceleration withdraws effectively high-energy particles from the thermal pool (analog of Maxwell demon).

Chernyshov, D. O.; Dogiel, V. A. [I. E. Tamm Theoretical Physics Division of P. N. Lebedev Institute, Leninskii pr 53, 119991 Moscow (Russian Federation); Ko, C. M., E-mail: cmko@astro.ncu.edu.tw [Institute of Astronomy, National Central University, JhongLi 320, Taiwan (China)

2012-11-10

357

Stable Laser-Driven Proton Beam Acceleration from a Two-Ion-Species Ultrathin Foil  

NASA Astrophysics Data System (ADS)

By using multidimensional particle-in-cell simulations, we present a new regime of stable proton beam acceleration which takes place when a two-ion-species shaped foil is illuminated by a circularly polarized laser pulse. In the simulations, the lighter protons are nearly instantaneously separated from the heavier carbon ions due to the charge-to-mass ratio difference. The heavy ion layer expands in space and acts to buffer the proton layer from the Rayleigh-Taylor-like (RT) instability that would have otherwise degraded the proton beam acceleration. A simple three-interface model is formulated to explain qualitatively the stable acceleration of the light ions. In the absence of the RT instability, the high quality monoenergetic proton bunch persists even after the laser-foil interaction ends.

Yu, Tong-Pu; Pukhov, Alexander; Shvets, Gennady; Chen, Min

2010-08-01

358

Rigorous analysis of nonlinear motion in particle accelerators  

NASA Astrophysics Data System (ADS)

Methods to obtain rigorous descriptions for the motion of ensembles of particles relative to a reference curve are developed. To account for the most general reference curves, a Lagrangian and Hamiltonian formulation of the relativistic motion of charged particles in electromagnetic fields in three dimensional curvilinear coordinates including torsion and with arclength as independent variable is derived. To allow for the use of the most general fields of particle optical devices, a wavelet-based method to include measured field data in the equations of motion in an appropriate manner is discussed. The method of transfer maps is a powerful tool for the study of weakly nonlinear dynamical systems, especially for the case of large phase space acceptances as in modern particle spectrographs, and the intricate dynamical behaviour of repetitive systems as in circular accelerators and storage rings. The Differential Algebraic (DA) techniques have proven fruitful for various computational problems in beam physics, including the determination of high order Taylor transfer maps. A new approach, the Remainder-enhanced Differential Algebraic (RDA) method, is presented, which extends the method to allow the determination of remainder bounds for functional dependencies and solutions of ODEs. First, the basic theory of the method is developed and applied to problems of verified optimization and quadrature. Next, schemes are derived that allow the construction of numerical integrators of arbitrary order with rigorous verification of the error for both the integration of individual initial conditions as well as Taylor transfer maps. The methods are based on a differential algebraic fixed point problem which is studied using Schauder's theorem and other functional analysis tools. Employing various compactness arguments on suitable function spaces in combination with the RDA tools, in each integration step a proof of existence of a solution within a tight inclusion is performed. The resulting computational tools are implemented in the arbitrary order beam physics code COSY INFINITY, and their behavior and performance is studied. Using integration orders around ten and suitable step sizes, rigorous remainder bounds in the range of 10-10 for transfer maps of orders around ten are obtained.

Makino, Kyoko

359

Focused transport of intense charged particle beams. Final technical report FY/93  

SciTech Connect

Many recent developments in accelerator technology have increased the need for a better understanding of the physics of intense-beam transport. Of particular interest to the work described here is the appearance, as beam intensities are increased, of a class of nonlinear phenomena which involve the collective interaction of the beam particles. Beam intensity, used as a measure of the importance of space-charge collective behavior, depends on the ratio of current to emittance. The nonlinear beam dynamics, and any resulting emittance growth, which are characteristic of the intense-beam regime, can therefore occur even at low currents in any accelerator system with sufficiently high intensity, especially in the low beta section. Furthermore, since emittance of a beam is difficult to reduce, the ultimate achievement of necessary beam luminosities requires the consideration of possible causes of longitudinal and transverse emittance growth at every stage of the beam lifetime. The research program described here has addressed the fundamental physics which comes into play during the transport, acceleration and focusing of intense beams. Because of the long term and ongoing nature of the research program discussed here, this report is divided into two sections. The first section constitutes a long term revue of the accomplishments which have resulted from the research effort reported, especially in pioneering the use of particle-in-cell (PIC) computer simulation techniques for simulation of the dynamics of space-charge-dominated beams in particle accelerators. The following section emphasizes, in more detail, the accomplishments of the FY 92/93 period immediately prior to the termination of this particular avenue of support. 41 refs.

NONE

1997-06-01

360

Laser-Driven Proton Beams: Acceleration Mechanism, Beam Optimization, and Radiographic Applications  

Microsoft Academic Search

This paper reviews recent experimental activity in the area of optimization, control, and application of laser-accelerated proton beams, carried out at the Rutherford Appleton Laboratory and the Laboratoire pour lpsilaUtilisation des Lasers Intenses 100 TW facility in France. In particular, experiments have investigated the role of the scale length at the rear of the plasma in reducing target-normal-sheath-acceleration acceleration efficiency.

Marco Borghesi; Carlo Alberto Cecchetti; Toma Toncian; Julien Fuchs; Lorenzo Romagnani; Satyabrata Kar; P. A. Wilson; Patrizio Antici; Patrick Audebert; Erik Brambrink; Ariane Pipahl; Munib Amin; Ralph Jung; Jens Osterholz; Oswald Willi; Wigen Nazarov; Robert J. Clarke; Margaret Notley; David Neely; Patrick Mora; Thomas Grismayer; Guy Schurtz; Angelo Schiavi; Yasuhiko Sentoku

2008-01-01

361

Accelerators for the PS neutrino beam  

NASA Astrophysics Data System (ADS)

A recent memorandum for an experimental proposal [1] was discussed during the CERN PS and SPS experimental committee (SPSC) of April 2011 and at the Research Board of June 2011. The proposed experiment, with objective to investigate the anomalous ?? ? ?e oscillations, aims at re-using the discontinued CERN PS Neutrino Facility (PSNF) and experimental zones to install a 150 ton liquid argon time projection chamber (LArTPC) as near detector and a 600 ton LArTPC as far detector. This article will summarize the experimental needs, the proposed facility layout, a primary beam production scheme and the requirements for the reconstruction of the PSNF.

Steerenberg, R.; Calviani, M.; Gschwendtner, E.; Pardons, A.; Vincke, H.

2013-02-01

362

Cooperative Pre-College Educational Programs at the Continuous Electron Beam Accelerator Facility (CEBAF)  

SciTech Connect

The Continuous Electron Beam Accelerator Facility (CEBAF), under construction in Newport News, Virginia, is a particle accelerator laboratory for nuclear physics research funded by the U.S. Department of Energy. CEBAF's research and supporting technologies offer a rich environment for capturing the interest of and augmenting the experience of pre-college teachers and students. This paper describes some of the pre-college educational programs underway at CEBAF in collaboration with schools, colleges, and business partners. The BEAMS program -- Becoming Enthusiastic About Math and Science -- is highlighted. BEAMS brings entire classes of fifth and sixth grade students with their teachers into CEBAF for a full school week of special science and math activities. A pilot program involving seven inner-city classes was conducted in spring 1991. The 1991/1992 program is well underway with fifty classes scheduled to visit CEBAF.

Hartline, Beverly; Strozak, Kathryn

1992-01-01

363

Three-dimensional simulations of high-current beams in induction accelerators with WARP3d  

SciTech Connect

For many issues relevant to acceleration and propagation of heavy-ion beams for inertial confinement fusion, understanding the behavior of the beam requires the self-consistent inclusion of the self-fields of the beams in multiple dimensions. For these reasons, the three-dimensional simulation code WARP3d A.Friedman was developed. The code combines the particle-in-cell plasma simulation technique with a realistic description of the elements which make up an accelerator. In this paper, the general structure of the code is reviewed and details of two ongoing applications are presented along with a discussion of simulation techniques used. The most important results of this work are presented.

Grote, D.P.; Friedman, A. [Lawrence Livermore National Laboratory, CA (United States); Haber, I. [Naval Research Laboratory, Washington, DC (United States)] [and others

1995-09-01

364

An improved 8 GeV beam transport system for the Fermi National Accelerator Laboratory  

SciTech Connect

A new 8 GeV beam transport system between the Booster and Main Ring synchrotrons at the Fermi National Accelerator Laboratory is presented. The system was developed in an effort to improve the transverse phase space area occupied by the proton beam upon injection into the Main Ring accelerator. Problems with the original system are described and general methods of beamline design are formulated. Errors in the transverse properties of a beamline at the injection point of the second synchrotron and their effects on the region in transverse phase space occupied by a beam of particles are discussed. Results from the commissioning phase of the project are presented as well as measurements of the degree of phase space dilution generated by the transfer of 8 GeV protons from the Booster synchrotron to the Main Ring synchrotron.

Syphers, M.J.

1987-06-01

365

Controlling the betatron oscillations of a wakefield-accelerated electron beam by temporally asymmetric laser pulses  

SciTech Connect

Based on two-dimensional particle-in-cell simulations, we investigated the electron beam's transverse oscillations by temporally asymmetric laser pulses in laser wakefield acceleration. Of particular interest in this article are the effects of ultrashort laser pulses having sharp rising and slow falling time scales. In this situation, the accelerated electron beam interacts directly with the laser field and undergoes transverse oscillations due to a phase-slip with the laser field. This oscillation can be matched with the betatron oscillation due to the focusing force of the ions, which can lead to a large transverse oscillation amplitude due to the resonance between them. Furthermore, in this case, the electron beam can be microbunched at the laser wavelength, which may provide the possibility for generation of a coherent synchrotron radiation.

Nam, Inhyuk [Graduate Program of Photonics and Applied Physics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Hur, Min Sup [School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Uhm, Han Sup [Electrophysics Department, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Hafz, Nasr A. M.; Suk, Hyyong [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of)

2011-04-15

366

GeV electron beams from cm-scale laser driven plasma based accelerators.  

NASA Astrophysics Data System (ADS)

GeV electron accelerators are essential to synchrotron radiation facilities and free electron lasers, and as modules for high-energy particle physics. Radiofrequency-based accelerators are limited to relatively low accelerating fields (10-50 MV/m) requiring tens to hundreds of metres to reach the multi-GeV beam energies needed to drive radiation sources, and many kilometres to generate particle energies of interest to high-energy physics. Laser-wakefield accelerators (LWFA) produce electric fields of order 10-100 GV/m enabling compact devices. Previously, the required laser intensity was not maintained over the distance needed to reach GeV energies, and hence acceleration was limited to the 100 MeV scale [1-3]. In this talk, results will be presented on the first demonstration of the generation of GeV-class beams using an intense laser beam. Laser pulses with peak power ranging from 10-50 TW were guided by a hydrogen filled capillary discharge waveguide [4]. Production of high-quality electron beams with 1 GeV energy by channelling a ˜40 TW peak power laser pulse in a 3.3 cm long gas-filled capillary discharge waveguide was observed [5]. Results will be discussed on the dependence of the electron beam characteristics on capillary properties, plasma density and laser parameters. [1] S.P.D. Mangles et al., Nature 431, 535-538 (2004). [2] C.G.R. Geddes et al., Nature 431, 538-541 (2004). [3] J. Faure et al., Nature 431, 541-544 (2004). [4] D.J. Spence and S.M. Hooker, Phys. Rev. E 63, 015401 (2001).[5] W.P. Leemans et al., submitted for publication.

Leemans, Wim

2006-10-01

367

Microsecond-pulsewidth, intense, light-ion beam accelerator.  

National Technical Information Service (NTIS)

A relatively long-pulsewidth (0.1-1 (mu)s) intense ion beam accelerator has been built for materials processing applications. An applied-B(sub r), magnetically-insulated extraction ion diode with dielectric flashover ion source is installed directly onto ...

D. J. Rej R. R. Bartsch H. A. Davis J. B. Greenly W. J. Waganaar

1993-01-01

368

Status of the CEBAF (Continuous Electron Beam Accelerator Facility) Injector.  

National Technical Information Service (NTIS)

The injector for the CEBAF cw superconducting linac consists of a 100 keV electron gun, two choppers and a buncher. A short, room temperature, graded-beta, sidecoupled accelerator is used to increase the electron beam energy to about 500 keV to produce a ...

W. T. Diamond R. Pico

1989-01-01

369

Accelerator Rings with Polarized Beams and Spin Manipulation  

Microsoft Academic Search

The basic formulas of describing polarization dynamics in accelerators will be presented. These include the equation of spin motion in a comoving coordinate frame for spin vectors, spin transport matrices, spin transport quaternions, and spinors. It will also be shown how spin flelds evolve in these four ways of descibing spin motion. Furthermore, some basic concepts of polarized beams in

Georg H. Hofistaetter

370

Reactive accelerated cluster erosion (RACE) by ionized cluster beams  

NASA Astrophysics Data System (ADS)

Beams of ionized clusters accelerated up to about 120 keV kinetic energy per cluster are used for cluster impact lithography. Chemical reactions of clusters of CO2, or of SF6, respectively, are found to assist the physical erosion by hypervelocity cluster impacts in yielding volatile products. Natural diamond, silicon and Pyrex glass have been microstructured showing very smooth eroded surfaces.

Gspann, J.

1996-05-01

371

Acceleration of beam ions during major radius compression in TFTR  

SciTech Connect

Tangentially co-injected deuterium beam ions were accelerated from 82 keV up to 150 keV during a major radius compression experiment in TFTR. The ion energy spectra and the variation in fusion yield were in good agreement with Fokker-Planck code simulations. In addition, the plasma rotation velocity was observed to rise during compression.

Wong, K.L.; Bitter, M.; Hammett, G.W.; Heidbrink, W.; Hendel, H.; Kaita, R.; Scott, S.; Strachan, J.D.; Tait, G.; Bell, M.G.

1985-09-01

372

Beam collimation and transport of laser-accelerated protons by a solenoid field  

Microsoft Academic Search

A pulsed high field solenoid was used in a laser-proton acceleration experiment to collimate and transport the proton beam that was generated at the irradiation of a flat foil by a high intensity laser pulse. 1012 particles at an energy of 2.3 MeV could be caught and transported over a distance of more than 240 mm. Strong space charge effects

K. Harres; I. Alber; A. Tauschwitz; V. Bagnoud; H. Daido; M. Günther; F. Nürnberg; A. Otten; M. Schollmeier; J. Schütrumpf; M. Tampo; M. Roth

2010-01-01

373

Hamiltonian methods for the study of polarized proton beam dynamics in accelerators and storage rings  

SciTech Connect

The equations of classical spin-orbit motion can be extended to a Hamiltonian system in 9-dimensional phase space by introducing a coupled spin-orbit Poisson bracket and Hamiltonian function. After this extension it becomes possible to apply the methods of the theory of Hamiltonian systems to the study of polarized particles beam dynamics in circular accelerators and storage rings. Some of those methods have been implemented in the computer code FORGET-ME-NOT.

Balandin, Vladimir; Golubeva, Nina [Department of Physics and Astronomy and NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); Institute for Nuclear Research of RAS, 60th October Anniversary Pr., 7a, Moscow (Russian Federation); Institute for Nuclear Research of RAS, 60th October Anniversary Pr., 7a, Moscow (Russian Federation)

1997-02-01

374

Recent progress of laser driven particle acceleration at Peking University  

NASA Astrophysics Data System (ADS)

Recently, radiation pressure acceleration (RPA) has been proposed and extensively studied, which shows that circularly polarized (CP) laser pulses can accelerate mono-energetic ion bunches in a phase-stable-acceleration (PSA) way from ultrathin foils. It is found that self-organizing proton beam can be stably accelerated to GeV in the interaction of a CP laser with a planar target at 1022 W/cm2. A project called Compact LAser Plasma proton Accelerator (CLAPA) is approved by MOST in China recently. A prototype of laser driven proton accelerator (1 to 15 MeV/1 Hz) based on the PSA mechanism and plasma lens is going to be built at Peking University in the next five years. It will be upgraded to 200 MeV later for applications such as cancer therapy, plasma imaging and fast ignition for inertial confine fusion.

Yan, Xue-Qing; Lin, Chen; Lu, Hai-Yang; Zhu, Kun; Zou, Yu-Bin; Wang, Hong-Yong; Liu, Bing; Zhao, Shuan; Zhu, Jiao; Geng, Yi-Xing; Fu, He-Zheng; Shang, Yong; Cao, Chao; Shou, Yin-Ren; Song, Wei; Lu, Yuan-Rong; Yuan, Zhong-Xi; Guo, Zhi-Yu; He, Xian-Tu; Chen, Jia-Er

2013-10-01

375

Vacuum chamber for containing particle beams  

DOEpatents

A vacuum chamber for containing a charged particle beam in a rapidly changing magnetic environment comprises a ceramic pipe with conducting strips oriented along the longitudinal axis of the pipe and with circumferential conducting bands oriented perpendicular to the longitudinal axis but joined with a single longitudinal electrical connection. When both strips and bands are on the outside of the ceramic pipe, insulated from each other, a high-resistance conductive layer such as nickel can be coated on the inside of the pipe.

Harvey, A.

1985-11-26

376

Vacuum chamber for containing particle beams  

DOEpatents

A vacuum chamber for containing a charged particle beam in a rapidly changing magnetic environment comprises a ceramic pipe with conducting strips oriented along the longitudinal axis of the pipe and with circumferential conducting bands oriented perpendicular to the longitudinal axis but joined with a single longitudinal electrical connection. When both strips and bands are on the outside of the ceramic pipe, insulated from each other, a high-resistance conductive layer, such as nickel can be coated on the inside of the pipe.

Harvey, Alexander (Los Alamos, NM)

1987-01-01

377

Beam physics developments for a rare isotope accelerator  

NASA Astrophysics Data System (ADS)

In support of a proposal for a Rare Isotope Accelerator facility, this thesis provides a preliminary analysis of a number of related subsystems. An overview of the requirements for the driver accelerator, production stations, and beam purification systems is presented. Some minor developments in the theory of beam transport and acceleration are presented in order to discuss a technique for isobar separation and multiple charge state selection. Changes to the COSY INFINITY code for carrying out map-based calculations are described. The results obtained by simulation are presented in detail for an isobar separator and a multiple charge state selection system. The concept of beam stripping is discussed in order to characterize the components of the multiple charge state beams. The production of rare isotopes via spallation of heavy targets using fast protons is discussed. Results obtained from experiments at an ISOL facility with direct and two-step target geometries are presented. Implications of the results to the design of future targets for rare isotope production are included. Some developments in beam diagnostic techniques are discussed along with the experimental results obtained from them.

Portillo, Mauricio

378

Dynamics of Charged Particles in an Adiabatic Thermal Beam Equilibrium  

SciTech Connect

Charged-particle motion is studied in the self-electric and self-magnetic fields of a well-matched, intense charged-particle beam and an applied periodic solenoidal magnetic focusing field. The beam is assumed to be in a state of adiabatic thermal equilibrium. The phase space is analyzed and compared with that of the well-known Kapchinskij-Vladimirskij (KV)-type beam equilibrium. It is found that the widths of nonlinear resonances in the adiabatic thermal beam equilibrium are narrower than those in the KV-type beam equilibrium. Numerical evidence is presented, indicating almost complete elimination of chaotic particle motion in the adiabatic thermal beam equilibrium.

Chen Chiping; Wei Haofei [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2010-11-04

379

Low-intensity beam diagnostics with particle detectors  

SciTech Connect

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.}

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

380

Neutral beam injection with an improved accelerator for LHD  

SciTech Connect

The beam profiles, port-through, rates and injection powers obtained with an improved accelerator with the multislot grounded grid are described. The accelerator has a combination of a steering grid with racetrack shaped aperture and multislot grounded grid to improve the beam optics. The optimal beam optics is obtained at the voltage ratio of 16.5-16.8, and the profiles are well fit by superposing multibeamlets with the divergent angles of 5.0 and 7.2 mrad along the direction parallel to the long and short axes of the slots of grounded grid. By adopting the racetrack shaped steering grid, the port-through rate increases from 34% to 38%, and the maximum injection power reaches 6 MW/187 keV.

Tsumori, K.; Osakabe, M.; Kaneko, O.; Takeiri, Y.; Nagaoka, K.; Oka, Y.; Ikeda, K.; Shibuya, M.; Asano, E.; Komada, S.; Kondo, T.; Sato, M. [National Institute for Fusion Science, 322-6 Oroshi Toki, Gifu 509-5292 (Japan)

2008-02-15

381

Digital computer simulation of charged particle beams and electrostatic lenses  

Microsoft Academic Search

A digital computer program for the simulation of charged particle beams ; in complex electrostatic lens systems is described. A large matrix is employed ; to simulate the potentials in rectangular or axisymmetric configurations, and ; relativistic trajectory computations are employed to simulate beams or charged ; particles of any energy. The beam may be injected with any energy or

J. E. Boers

1973-01-01

382

a Fractal-Discrete Scheme for Cosmic Particle Acceleration  

Microsoft Academic Search

The present article is an attempt to provide a parametrization for particle acceleration probabilities in the very high energy range combining a discrete fractal scheme for interaction probabilities and the observational fact of a power law energy spectrum for cosmic ray particles.

A. L. Dos Santos; L. P. L. de Oliveira; B. E. J. Bodmann; M. T. Vilhena

2007-01-01

383

Solar Energetic Particle Acceleration in Refracting Coronal Shock Waves  

Microsoft Academic Search

Gradual solar energetic particle (SEP) events are known to be correlated with coronal mass ejections (CMEs) and soft X-ray flares. The current paradigm of particle acceleration in these events attributes it to CME-driven shock waves in the solar corona and in interplanetary space. Even in small gradual SEP events related to CMEs with speeds in the (possibly submagnetosonic) range of

Rami Vainio; Josef I. Khan

2004-01-01

384

Particle acceleration from reconnection in the geomagnetic tail  

SciTech Connect

Acceleration of charged particles in the near geomagnetic tail, associated with a dynamic magnetic reconnection process, was investigated by a combined effort of data analysis, using Los Alamos data from geosynchronous orbit, MHD modeling of the dynamic evolution of the magnetotail, and test particle tracing in the electric and magnetic fields obtained from the MHD simulation.

Birn, J.; Borovsky, J.E.; Thomsen, M.F.; McComas, D.J.; Reeves, G.D.; Belian, R.D. [Los Alamos National Lab., NM (United States); Hesse, M. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Schindler, K. [Ruhr-Univ., Bochum (Germany)

1997-08-01

385

Stochastic particle acceleration in multiple magnetic islands during reconnection.  

PubMed

A nonthermal particle acceleration mechanism involving the interaction of a charged particle with multiple magnetic islands is proposed. The original Fermi acceleration model, which assumes randomly distributed magnetic clouds moving at random velocity V(c) in the interstellar medium, is known to be of second-order acceleration of O(V(c)/c)(2) owing to the combination of head-on and head-tail collisions. In this Letter, we reconsider the original Fermi model by introducing multiple magnetic islands during reconnection instead of magnetic clouds. We discuss that the energetic particles have a tendency to be distributed outside the magnetic islands, and they mainly interact with reconnection outflow jets. As a result, the acceleration efficiency becomes first order of O(V(A)/c), where V(A) and c are the Alfvén velocity and the speed of light, respectively. PMID:22540708

Hoshino, Masahiro

2012-03-28

386

Gamma-Ray Bursts and Particle Acceleration  

NASA Astrophysics Data System (ADS)

Gamma-ray bursts (GRBs) are possible sources of ultra-high-energy cosmic rays (UHE-CRs). To test the GRB origin of UHECRs, it is essential to search for characteristic, proton-induced signatures of secondary radiation. In this paper we present our recent results of Monte Carlo simulations that model the broadband prompt emission of GRBs including various processes associated with electrons and protons accelerated to high energies. The most notable effect of accelerated protons on the high-energy spectra is the synchrotron emission from secondary electron-positron pairs injected by photomeson interactions. Secondary photons tend to make the spectra flat, so a spectral flattening in the GeV-TeV bands may serve as a signature of UHECR acceleration. In some cases, the proton-induced photons overwhelm the photon field, resulting in a spectral peak due to inverse Compton emission from secondary pairs located around 107 eV. We can expect to detect synchrotron photons from protons or muons. Observations with GLAST or with atmospheric Cerenkov telescopes can provide useful estimates of the bulk Lorents factor and can constrain the proton acceleration efficiency.

Asano, Katsuaki

2008-08-01

387

Gamma-Ray Bursts and Particle Acceleration  

SciTech Connect

Gamma-ray bursts (GRBs) are possible sources of ultra-high-energy cosmic rays (UHE-CRs). To test the GRB origin of UHECRs, it is essential to search for characteristic, proton-induced signatures of secondary radiation. In this paper we present our recent results of Monte Carlo simulations that model the broadband prompt emission of GRBs including various processes associated with electrons and protons accelerated to high energies. The most notable effect of accelerated protons on the high-energy spectra is the synchrotron emission from secondary electron-positron pairs injected by photomeson interactions. Secondary photons tend to make the spectra flat, so a spectral flattening in the GeV-TeV bands may serve as a signature of UHECR acceleration. In some cases, the proton-induced photons overwhelm the photon field, resulting in a spectral peak due to inverse Compton emission from secondary pairs located around 10{sup 7} eV. We can expect to detect synchrotron photons from protons or muons. Observations with GLAST or with atmospheric Cerenkov telescopes can provide useful estimates of the bulk Lorents factor and can constrain the proton acceleration efficiency.

Asano, Katsuaki [Interactive Research Center for Science, Graduate School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

2008-08-28

388

Educating the next generation in the science and technology of plasmas, beams and accelerators  

NASA Astrophysics Data System (ADS)

Accelerators are essential tools for discovery in fundamental physics, biology, and chemistry. Particle beam based instruments in medicine, industry and national security constitute a multi-billion dollar per year industry. More than 55,000 peer-reviewed papers having accelerator as a keyword are available on the Web. Yet only a handful of universities offer any formal training in accelerator science. Several reasons can be cited: 1) The science and technology of non-neutral plasmas cuts across traditional academic disciplines. 2) Electrical engineering departments have evolved toward micro- and nano-technology and computing science. 3) Nuclear physics departments have atrophied. 4) With few exceptions, interest at individual universities is not extensive enough to support a strong faculty line. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed an educational paradigm that, over the past twenty-years, has granted more university credit in accelerator / beam science and technology than any university in the world. Governed and supported by a consortium of nine DOE laboratories and two NSF university laboratories, USPAS offers a responsive and balanced curriculum of science, engineering, and hands-on courses. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, cross-disciplinary research areas such as high energy density physics.

Barletta, Wiliam

2007-11-01

389

Fibre optic radiation sensor systems for particle accelerators  

Microsoft Academic Search

Two different fibre optic dosimeter systems based on the radiation-induced increase of fibre attenuation are presented. The systems allow on-line measurement of the accumulated dose along accelerator beam lines (“distributed” sensor) as well as at fixed positions in selected accelerator sections (local sensors). Fibre properties, system layout and results of measurements obtained during operation of the TESLA11Tera Electron Volt Energy

H. Henschel; M. Körfer; J. Kuhnhenn; U. Weinand; F. Wulf

2004-01-01

390

The Long-Term Future of Particle Accelerators  

Microsoft Academic Search

This talk is going to deal with the big machines that are used to do research on the smallest parts of matter and on the way\\u000a they interact. In fact, at the bottom of all physical phenomena are particles and forces between particles. To observe these\\u000a on an even smaller scale, we have to accelerate the particles to high energy.

Simon van Meer

391

Extreme high vacuum technology for particle accelerators  

Microsoft Academic Search

Linearly distributed pumping is highly desirable for Storage Rings to limit the pressure rise due to the outgassing induced by the circulating beams. As a byproduct, linear pumping allows extremely low pressures (down to the 10-1 Torr range) to be achieved in static vacuum conditions. Non Evaporable Getters (NEGs), in the form either of a strip as adopted for LEP

C. Benvenuti

2001-01-01

392

Target motion tracking with a scanned particle beam  

Microsoft Academic Search

Treatment of moving targets with scanned particle beams results in local over- and under-dosage due to interplay of beam and target motion. To mitigate the impact of respiratory motion, a motion tracking system has been developed and integrated in the therapy control system at Gesellschaft fuer Schwerionenforschung. The system adapts pencil beam positions as well as the beam energy according

Christoph Bert; Nami Saito; Alexander Schmidt; Naved Chaudhri; Dieter Schardt; Eike Rietzel

2007-01-01

393

Modeling the Solar Atmospheric Response to Flare-Accelerated Ion Beams  

NASA Astrophysics Data System (ADS)

In the standard model of the impulsive phase of flares, particles accelerated to high energy at the flare reconnection site are the main source of heating in the lower atmosphere. These particles travel down magnetic flux tubes transferring their energy to the ambient plasma along the way through Coulomb collisions. It is likely that electrons as well as ions are accelerated by flare reconnection, and much work has been done understanding the response of the solar atmosphere to electron beam heating. However, since the presence of ions is much more difficult to directly detect than electrons, their role in flare heating is less understood. To better understand this, we have performed simulations of the solar atmospheric response to ion beam heating. Our models solve the equations of non-LTE radiation hydrodynamics for the conditions of the flaring solar atmosphere with an ion beam energy source term. Radiative transfer is solved in detail for many important optically thick hydrogen and helium transitions and numerous optically thin EUV lines. Thus, these models are ideally suited to study the emission that is produced during flares. We will pay special attention to understanding how key EUV lines respond to ion beam heating. We will compare these results to simulations performed with electron beam heating.

Allred, Joel C.; Holman, G. D.

2012-05-01

394

The use of electromagnetic particle-in-cell codes in accelerator applications  

SciTech Connect

The techniques developed for the numerical simulation of plasmas have numerous applications relevant to accelerators. The operation of many accelerator components involves transients, interactions between beams and rf fields, and internal plasma oscillations. These effects produce non-linear behavior which can be represented accurately by particle in cell (PIC) simulations. We will give a very brief overview of the algorithms used in PIC Codes. We will examine the range of parameters over which they are useful. We will discuss the factors which determine whether a two or three dimensional simulation is most appropriate. PIC codes have been applied to a wide variety of diverse problems, spanning many of the systems in a linear accelerator. We will present a number of practical examples of the application of these codes to areas such as guns, bunchers, rf sources, beam transport, emittance growth and final focus. 8 refs., 8 figs., 2 tabs.

Eppley, K.

1988-12-01

395

Gamma-Ray Bursts and Particle Acceleration  

Microsoft Academic Search

Gamma-ray bursts (GRBs) are possible sources of ultra-high-energy cosmic rays (UHE-CRs). To test the GRB origin of UHECRs, it is essential to search for characteristic, proton-induced signatures of secondary radiation. In this paper we present our recent results of Monte Carlo simulations that model the broadband prompt emission of GRBs including various processes associated with electrons and protons accelerated to

Katsuaki Asano; Katsuaki

2008-01-01

396

Particle physicist's dreams about PetaelectronVolt laser plasma accelerators  

SciTech Connect

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

Vesztergombi, G. [KFKI-RMKI. 1525-H Budapest P.O.B. 49. (Hungary)

2012-07-09

397

NOVEL METHOD FOR BEAM DYNAMICS STUDY USING AN ALPHA PARTICLE SOURCE  

Microsoft Academic Search

A new method for beam dynamic study has been devel- oped by using alpha particles emitted from a commercially available radioactive source. The precision of the method is estimated in consideration of an event rate in a reason- able measuring time and statistical accuracy. The method could be applied not only for a circular accelerator but also for a unit

A. Sato; M. Aoki; Y. Arimoto; T. Itahashi; Y. Kuno; T. Oki; M. Yoshida

398

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

NASA Astrophysics Data System (ADS)

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.

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

399

High-intensity ion sources for accelerators with emphasis on H- beam formation and transport (invited)  

NASA Astrophysics Data System (ADS)

This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as dc discharge-driven and rf-driven multicusp sources, Penning-type, and electron cyclotron resonance-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber, and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed, ionization mechanism, beam formation, and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail.

Keller, R.

2010-02-01

400

High-intensity ion sources for accelerators with emphasis on H- beam formation and transport (invited).  

PubMed

This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as dc discharge-driven and rf-driven multicusp sources, Penning-type, and electron cyclotron resonance-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber, and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed, ionization mechanism, beam formation, and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail. PMID:20192434

Keller, R

2010-02-01

401

High-intensity ion sources for accelerators with emphasis on H-beam formation and transport  

SciTech Connect

This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as d. c. discharge- and rf-driven multicusp sources. Penning-type and ECR-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber-. and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed. ionization mechanism, beam formation and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail.

Keller, Roderich [Los Alamos National Laboratory

2009-01-01

402

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC  

SciTech Connect

to couple the THUNDER undulator to the LOASIS Lawrence Berkeley National Laboratory (LBNL) laser wakefield accelerator (LWFA). Currently the LWFA has achieved quasi-monoenergetic electron beams with energies up to 1 GeV. These ultra-short, high-peak-current, electron beams are ideal for driving a compact XUV free electron laser (FEL). Understanding the electron beam properties such as the energy spread and emittance is critical for achieving high quality light sources with high brightness. By using an insertion device such as an undulator and observing changes in the spontaneous emission spectrum, the electron beam energy spread and emittance can be measured with high precision. The initial experiments will use spontaneous emission from 1.5 m of undulator. Later experiments will use up to 5 m of undulator with a goal of a high gain, XUV FEL.

Bakeman, M.S.; Fawley, W.M.; Leemans, W. P.; Nakamura, K.; Robinson, K.E.; Schroeder, C.B.; Toth, C.

2009-05-04

403

NOTE: Blood irradiation with accelerator produced electron beams  

NASA Astrophysics Data System (ADS)

Blood and blood products are irradiated with gamma rays to reduce the risk of graft versus host disease (GVHD). A simple technique using electron beams produced by a medical linear accelerator has been studied to evaluate irradiation of blood and blood products. Variations in applied doses for a single field 20 MeV electron beam are measured in a phantom study. Doses have been verified with ionization chambers and commercial diode detectors. Results show that the blood product volume can be given a relatively homogeneous dose to within 6% using 20 MeV electrons without the need to rotate the blood bags or the beam entry point. The irradiation process takes approximately 6.5 minutes for 30 Gy applied dose to complete as opposed to 12 minutes for a dual field x-ray field irradiation at our centre. Electron beams can be used to satisfactorily irradiate blood and blood products in a minimal amount of time.

Butson, M. J.; Cheung, T.; Yu, P. K. N.; Stokes, M. J.

2000-11-01

404

Diffusive particle acceleration by an ensemble of shock waves  

NASA Astrophysics Data System (ADS)

The theory of diffusive acceleration of cosmic rays by shock waves (first order Fermi acceleration) is generalized to the case that the particles propagate through a medium in which many shocks are present simultaneously. The basic assumption underlying the theory presented here is that the typical time between two shock transitions a particle undergoes is much longer than the time of spectral formation at an individual shock. This allows the separation of the process of shock acceleration from other propagation effects. We consider as such particle escape from the system (catastrophic losses) and continuous energy losses. The interplay of shock acceleration and these other propagation effects leads to the formation of particle spectra with spectral features such as breaks at characteristic momenta, or humps. In particular, for special choices of the parameters describing the propagation of cosmic rays, results derived earlier (such as the spectral slope of particles produced by a periodic shock structure derived by Spruit, or the particle pile-up obtained by Schlickeiser) are reobtained. The approach followed in this paper is then compared with the one used by Blandford & Ostriker where they included an integral operator in the cosmic ray transport equation to describe impulsive acceleration. The theory considered here may find its application in the study of cosmic ray (re)acceleration in our galaxy, but is likely to be as important in other astrophysical environments, such as the central regions of active galactic nuclei, where we expect highly turbulent flows to be present. It can therefore be expected that in such objects there is a region in which many shocks are present. The multiple shock acceleration theory may then be used to study the formation of spectra in such objects.

Schneider, P.

1993-10-01

405

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

Microsoft Academic Search

We present 2D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low \\\\(~1016 W\\/cm2\\\\) and high \\\\(~1018 W\\/cm2\\\\) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations.

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

2001-01-01

406

Particle-in-cell modeling of plasma-based accelerators in two and three dimensions  

Microsoft Academic Search

In this dissertation, a fully object-oriented, fully relativistic, multidimensional Particle-In-Cell code was developed and applied to answer key questions in plasma- based accelerator research. The simulations increase the understanding of the processes in laser plasma and beam- plasma interaction, allow for comparison with experiments, and motivate the development of theoretical models. The simulations support the idea that the injection of

Roy Gerrit Hemker

2000-01-01

407

The low energy high current particle accelerator at the Colorado School of Mines  

NASA Astrophysics Data System (ADS)

The General Ionex model 1545 particle accelerator recently acquired by the Colorado School of Mines Physics Department is described. Operating conditions such as beam energy, currents, ionic species, energy resolution, and vacuum are described. Measurements of radiative capture reactions of protons on D, 6Li, 7Li, and 11B between bombarding energies of 10 and 180 keV are reported. Application of these measurements to the diagnostics of advanced fuel controlled fusion reactors is suggested.

Cecil, F. E.; Ferg, D.; King, R.; Kriss, B.; Liu, H.; Scorby, J.

1989-04-01

408

Particle simulation code for longitudinal dynamics of heavy ion beams  

SciTech Connect

A particle computer simulation code is presented, designed to describe the longitudinal motion of charged particles in a nonneutralized beam. The code is 1-d, electrostatic, and is capable of simulating coasting or bunched beams, cold or warm, with arbitrary wall impedance. External focusing forces are introduced in the bunched beam case. A variety of distribution functions can be represented. The code is self-consistent and it can follow both the linear and nonlinear evolution of a beam.

Sternlieb, A.; Smith, L.; Laslett, L.J.; Bisognano, J.; Haber, I.

1981-01-01

409

Measurement of particle residence time and particle acceleration in an arterial model by an automatic particle-tracking system  

NASA Astrophysics Data System (ADS)

An automatic three dimensional particle tracking technique has been applied to the study of particle motion in a modeled flow field. Equipment used for this technique is a high speed video recording system, Kodak Ektapro 1000, with two cameras arranged relatively orthogonally to take sequential pictures of fluid particle motion in two different views. Two fluid dynamic properties derived by this automatic three dimensional particle tracking technique are presented in this paper. These properties are particle residence time and particle acceleration.

Tsao, Raychang; Jones, Steven A.; Giddens, Don P.; Zarins, Christopher K.; Glagov, Seymour

1993-01-01

410

Ultralow emittance electron beams from a laser-wakefield accelerator  

NASA Astrophysics Data System (ADS)

Using quadrupole scan measurements we show laser-wakefield accelerated electrons to have a normalized transverse emittance of 0.21-0.02+0.01?mmmrad at 245 MeV. We demonstrate a multishot and a single-shot method, the mean emittance values for both methods agree well. A simple model of the beam dynamics in the plasma density downramp at the accelerator exit matches the source size and divergence values inferred from the measurement. In the energy range of 245 to 300 MeV the normalized emittance remains constant.

Weingartner, R.; Raith, S.; Popp, A.; Chou, S.; Wenz, J.; Khrennikov, K.; Heigoldt, M.; Maier, A. R.; Kajumba, N.; Fuchs, M.; Zeitler, B.; Krausz, F.; Karsch, S.; Grüner, F.

2012-11-01

411

Quasimonoenergetic electron beams from laser wakefield acceleration in pure nitrogen  

SciTech Connect

Quasimonoenergetic electron beams with maximum energy >0.5 GeV and 2 mrad divergence have been generated in pure nitrogen gas via wakefield acceleration with 80 TW, 30 fs laser pulses. Long low energy tail features were typically observed due to continuous ionization injection. The measured peak electron energy decreased with the plasma density, agreeing with the predicted scaling for electrons. The experiments showed a threshold electron density of 3x10{sup 18}cm{sup -3} for self-trapping. Our experiments suggest that pure Nitrogen is a potential candidate gas to achieve GeV monoenergetic electrons using the ionization induced injection scheme for laser wakefield acceleration.

Mo, M. Z.; Ali, A.; Fedosejevs, R. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Fourmaux, S.; Lassonde, P.; Kieffer, J. C. [INRS-EMT, Universite du Quebec, 1650 Lionel Boulet, Varennes, Quebec J3X 1S2 (Canada)

2012-02-13

412

Calculation of beam loading and particle trapping using a quasistatic simulation code  

NASA Astrophysics Data System (ADS)

Plasma based particle acceleration requires the generation of plasma wave wakes which maintain their coherence over long distances. For example in Laser Wake Field Acceleration (LWFA) schemes the laser pulse must propagate tens of centimeters, which corresponds to many Rayleigh lengths, and in Plasma Wake Field Acceleration (PWFA) the particle beam must be propagated many meters. These wakes, and their effect on the driver (Laser or particle beam) can be simulated efficiently in the quasistatic approximation [1,2]. In this approximation the driver does not evolve during the time a plasma electron spends in the driver. Particles that are trapped in the wake must be treated by an alternate algorithm. Here we modify the 2D code WAKE [1] to treat such particles. We also implement an algorithm that allows for plasma particle to become trapped particles if they gain sufficient energy. Similar implementations have been made in the 3D code QUICKPIC [2]. These changes in WAKE will give users a tool that can be used on a desk-top machine to simulated GeV acceleration. [1] P. Mora and T. M. Antonsen Jr., Phys Plasma 4, 217 (1997) [2] C. Huang et al., J. Comp Phys., to be published.

Morshed, Sepehr; Antonsen, Thomas; Huang, Chengkun; Mori, Warren

2006-10-01

413

On scaling properties of crossing the third-order resonance in particle accelerator  

SciTech Connect

We study effects of charged particle beams crossing a third-order resonance in an accelerator. The distortion of invariant torus during the resonance crossing is used to set 20% emittance growth or 2.5% of trap fraction as the critical resonance strength. We find a simple scaling law for the critical resonance strength vs the tune ramp rate and the initial emittance. The scaling law can be derived by solving Hamilton's equation of motion with stationary phase condition. Such scaling law can be used to evaluate the performance in high power accelerators, such as the FFAG and cyclotron.

Lee, S.Y.; Pang, X.; Jing, Y.; Luo, T.; /Indiana U.; Ng, K.Y.; /Fermilab

2011-12-01

414

Study of a multi-beam accelerator driven thorium reactor  

SciTech Connect

The primary advantages that accelerator driven systems have over critical reactors are: (1) Greater flexibility regarding the composition and placement of fissile, fertile, or fission product waste within the blanket surrounding the target, and (2) Potentially enhanced safety brought about by operating at a sufficiently low value of the multiplication factor to preclude reactivity induced events. The control of the power production can be achieved by vary the accelerator beam current. Furthermore, once the beam is shut off the system shuts down. The primary difference between the operation of an accelerator driven system and a critical system is the issue of beam interruptions of the accelerator. These beam interruptions impose thermo-mechanical loads on the fuel and mechanical components not found in critical systems. Studies have been performed to estimate an acceptable number of trips, and the value is significantly less stringent than had been previously estimated. The number of acceptable beam interruptions is a function of the length of the interruption and the mission of the system. Thus, for demonstration type systems and interruption durations of 1sec < t < 5mins, and t > 5mins 2500/yr and 50/yr are deemed acceptable. However, for industrial scale power generation without energy storage type systems and interruption durations of t < 1sec., 1sec < t < 10secs., 10secs < t < 5mins, and t > 5mins, the acceptable number of interruptions are 25000, 2500, 250, and 3 respectively. However, it has also been concluded that further development is required to reduce the number of trips. It is with this in mind that the following study was undertaken. The primary focus of this study will be the merit of a multi-beam target system, which allows for multiple spallation sources within the target/blanket assembly. In this manner it is possible to ameliorate the effects of sudden accelerator beam interruption on the surrounding reactor, since the remaining beams will still be supplying source neutrons. The proton beam will be assumed to have an energy of 1 GeV, and the target material will be natural lead, which will also be the coolant for the reactor assembly. Three proton beam arrangements will be considered, first a single beam (the traditional arrangement) with an entry at the assembly center, two more options will consist of three and six entry locations. The reactor fuel assembly parameters will be based on those of the S-PRISM fast reactor proposed by GE, and the fuel composition and type will be based on that proposed by Aker Solutions for use in their accelerator driven thorium reactor. The following table summarizes the parameters to be used in this study. The isotopic composition of the fertile material is 100% Th-232, and the plutonium isotopic distribution corresponds to that characteristic of the discharge from a typical LWR, following five years of decay. Thus, the isotopic distribution for the plutonium is; Pu-238 2.5%, Pu-239 53.3%, Pu-240 25.1%, Pu-241 11.8%, and Pu-242 7.3%.

Ludewig, H.; Aronson, A.

2011-03-01

415

Auroral beam-plasma interactions - Particle correlator investigations  

NASA Astrophysics Data System (ADS)

Plasma wave instabilities may occur above discrete auroral arcs where the natural accelerated auroral electron component meets the cold ionospheric plasma. These wave-particle interactions were studied on the CAESAR II rocket by measuring the modulations in energetic electron flux in the frequency ranges 0-10 kHz and 0-10 MHz. Near apogee (700 km), a strong modulation of 7.5-keV electrons at 1.4 MHz was observed where df(v)/dv was positive, just below the auroral beam velocity. The measurement is shown to be consistent with instabilities driven by both Landau and cyclotron resonant interactions with upper-hybrid waves, and also with the observation of modulations at 2.65 MHz on a low-altitude rocket flight (apogee 230 km).

Gough, M. Paul; Christiansen, Peter J.; Wilhelm, Klaus

1990-08-01

416

Linear Accelerators  

SciTech Connect

In the linear accelerators the particles are accelerated by either electrostatic fields or oscillating radio frequency (RF) fields. Accordingly the linear accelerators are divided by three large groups: electrostatic, induction and RF accelerators. Overview of different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of the beam focusing in linacs are described.

Sidorin, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

2007-11-26

417

Characterization of a simple explosively driven particle acceleration  

SciTech Connect

Experiments are carried out to characterize the performance of a compact cylindrical (2-inch x 3-inch-long) single-point detonation ring-lit fast shock tube that has been designed to accelerate particles to velocity in excess of 10 km/s. The experimental results from the study of propellant flow and plate acceleration will be presented and compared with the code calculation. Various interesting measurement techniques will also be discussed.

Tan, T.H.; Fritz, J.N.; Marsh, S.P.; McQueen, R.G.; Steele, R.D.

1987-01-01

418

Feedback control of coupled-bunch instabilities [particle accelerators  

Microsoft Academic Search

The next generation of synchrotron light sources and particle accelerators will require active feedback systems to control multi-bunch instabilities. Stabilizing hundreds or thousands of potentially unstable modes in these accelerator designs presents many technical challenges. Feedback systems to stabilize coupled-bunch instabilities may be understood in the frequency domain (mode-based feedback) or in the time domain (bunch-by-bunch feedback). In both approaches

J. D. Fox; N. Eisen; H. Hindi; I. Linscott; G. Oxoby; L. Sapozhnikov; M. Serio

1993-01-01

419

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

NASA Astrophysics Data System (ADS)

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.

Xiao, Chen; He, Yuan; Yuan, You-Jin; Yao, Qing-Gao; Wang, Zhi-Jun; Chang, Wei; Liu, Yong; Xia, Jia-Wen

2011-05-01

420

Effects of the beamfront velocity on collective acceleration with relativistic electron beams  

Microsoft Academic Search

Observations of accelerated protons during the injection of rotating relativistic electron beams into neutral hydrogen (50-400 mtorr) indicate that ions from the beam-formed plasma are trapped and accelerated by a potential well at the beamfront. Measurements show that the number of accelerated protons decreases as the beamfront velocity is increased. Moreover, at a given velocity, the number accelerated is relatively

D. N. Spector; K. A. Gerber; J. D. Sethian; R. A. Mahaffey; R. A. Meger

1980-01-01

421

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES: Self-Injection and Acceleration of Monoenergetic Electron Beams from Laser Wakefield Accelerators in a Highly Relativistic Regime  

NASA Astrophysics Data System (ADS)

Self-injection and acceleration of monoenergetic electron beams from laser wakefield accelerators are first investigated in the highly relativistic regime, using 100 TW class, 27fs laser pulses. Quasi-monoenergetic multi-bunched beams with energies as high as multi-hundred MeV are observed with simultaneous measurements of side-scattering emissions that indicate the formation of self-channelling and self-injection of electrons into a plasma wake, referred to as a 'bubble'. The three-dimensional particle-in-cell simulations confirmed multiple self-injection of electron bunches into the bubble and their beam acceleration with gradient of 1.5GeV/cm.

Yoshitama, H.; Kameshima, T.; Gu, Yu-Qiu; Guo, Yi; Jiao, Chun-Ye; Liu, Hong-Jie; Peng, Han-Sheng; Tang, Chuan-Ming; Wang, Xiao-Dong; Wen, Xian-Lun; Wen, Tian-Shu; Wu, Yu-Chi; Zhang, Bao-Han; Zhu, Qi-Hua; Huang, Xiao-Jun; An, Wei-Min; Hung, Wen-Hui; Tang, Chuan-Xiang; Lin, Yu-Zheng; Wang, Xiao-Dong; Chen, Li-Ming; Kotaki, H.; Kando, M.; Nakajima, K.

2008-08-01

422

Particle accelerators inside spinning black holes.  

PubMed

On the basis of the Kerr metric as a model for a spinning black hole accreting test particles from rest at infinity, I show that the center-of-mass energy for a pair of colliding particles is generically divergent at the inner horizon. This shows not only that classical black holes are internally unstable, but also that Planck-scale physics is a characteristic feature within black holes at scales much larger that the Planck length. The novel feature of the divergence discussed here is that the phenomenon is present only for black holes with rotation, and in this sense it is distinct from the well-known Cauchy horizon instability. PMID:20867083

Lake, Kayll

2010-05-26

423

Microbunching and Beam Break Up in DUV FEL Accelerator  

SciTech Connect

We present the results of electron beam longitudinal modulation studies in the DUV-FEL accelerator. For bunch length determination we used the 'zero-phasing' method, based on a measurement of the chirped electron bunch energy spectra. The measurements revealed a spiky structure in the longitudinal phase space [1]. A model based on space charge effect is considered [2] to explain of the obtained phenomena. The analysis of the energy spectra has shown a sensitivity of the structure to the electron beam peak current, energy and longitudinal non-uniformity of the RF gun drive laser. Analytical calculations have demonstrated a qualitative agreement with experimental observations. Several experiments have been made to compare with theory; measured results are reviewed in this paper. The obtained effect is briefly discussed in relation to high brightness accelerators.

Shaftan, T.; Carr, L.; Loos, H.; Sheehy, B.; Graves, William S.; Huang, Z.; Limborg, C.G.; /Brookhaven /MIT /SLAC

2008-03-17

424

Million revolution accelerator beam instrument for logging and evaluation  

SciTech Connect

A data acquisition and analysis instrument for the processing of accelerator beam position monitor (BPM) signals has been assembled and used preliminarily for beam diagnosis of the Fermilab accelerators. Up to eight BPM (or other analogue) channels are digitized and transmitted to an acquisition Sun workstation and from there both to a monitor workstation and a workstation for off-line (but immediate) data analysis. A coherent data description format permits fast data object transfers to and from memory, disk and tape, across the Sun ethernet. This has helped the development of both general purpose and experiment-specific data analysis, presentation and control tools. Flexible software permits immediate graphical display in both time and frequency domains. The instrument acts simultaneously as a digital oscilloscope, as a network analyzer and as a correlating, noise-reducing spectrum analyzer. 2 refs., 3 figs.

Peggs, S.; Saltmarsh, C.; Talman, R.

1988-03-01

425

Bipolar pulse generator for intense pulsed ion beam accelerator  

SciTech Connect

A new type of pulsed ion beam accelerator named ''bipolar pulse accelerator'' (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138 kV, 72 ns) and the second pulse (+130 kV, 70 ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time.

Ito, H.; Igawa, K.; Kitamura, I.; Masugata, K. [Department of Electrical and Electronic System Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)

2007-01-15

426

Bipolar pulse generator for intense pulsed ion beam accelerator  

NASA Astrophysics Data System (ADS)

A new type of pulsed ion beam accelerator named ``bipolar pulse accelerator'' (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138 kV, 72 ns) and the second pulse (+130 kV, 70 ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time.

Ito, H.; Igawa, K.; Kitamura, I.; Masugata, K.

2007-01-01

427

NON-STANDARD ENERGY SPECTRA OF SHOCK-ACCELERATED SOLAR PARTICLES  

SciTech Connect

We consider a numerical model for the shock acceleration of energetic ions in the magnetic environment of the solar corona. The model is motivated by observations of the deka-to-hecto-MeV proton energy spectra, ion and electron timing, and abundances in the beginning of major solar energetic particle (SEP) events, prior to the event's main phase associated with coronal mass ejection (CME) driven shock in the solar wind. Inasmuch as the obliquity of the CME-liftoff-associated shocks in solar corona and hence the seed-particle supply for the shock acceleration are essentially time dependent, a steady state energy spectrum of accelerated protons near the shock could not be attained. Energy spectrum of the SEP emission depends on the spatial and energy distribution of seed particles for the coronal shock acceleration, on the shock wave history, and on the location and scenario of the energetic particle escape into the interplanetary medium. We use a numerical model of the shock acceleration on a semicircular magnetic field line to learn a significance of different effects. If the shock geometry in a particular magnetic tube changes from nearly parallel to perpendicular, the resulting SEP spectrum in most distant sections of the tube, e.g., at the top of a transequatorial loop, resembles a wide beam, which is very different from the standard power-law spectrum that would be expected in a steady state. Possible escape of the shock-accelerated particles from more than one coronal location, stochastic re-acceleration, and the magnetic tube expansion can make the SEP spectra even more complicated.

Kocharov, Leon; Vainio, Rami; Pomoell, Jens [Department of Physics, P.O. Box 64, University of Helsinki, FI-00014 (Finland); Valtonen, Eino [Space Research Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 (Finland); Klassen, Andreas [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet Kiel, D-24118 (Germany); Young, C. Alex [ADNET Systems Inc., NASA Goddard Space Flight Center, Greenbelt, MD 20850 (United States)

2012-07-01