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Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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1

Linear particle accelerator with seal structure between electrodes and insulators  

DOE Patents (OSTI)

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

Broadhurst, John H. (Golden Valley, MN)

1989-01-01T23:59:59.000Z

2

Linear Accelerator  

NLE Websites -- All DOE Office Websites (Extended Search)

Linear Accelerator (LINAC) The core of the LANSCE facility is one of the nation's most powerful proton linear accelerators or LINAC. The LINAC at LANSCE has served the nation since...

3

A threshold for laser-driven linear particle acceleration in unbounded vacuum  

E-Print Network (OSTI)

We hypothesize that a charged particle in unbounded vacuum can be substantially accelerated by a force linear in the electric field of a propagating electromagnetic wave only if the accelerating field is capable of bringing ...

Wong, Liang Jie

2011-01-01T23:59:59.000Z

4

Non-perturbative aspects of particle acceleration in non-linear electrodynamics  

E-Print Network (OSTI)

We undertake an investigation of particle acceleration in the context of non-linear electrodynamics. We deduce the maximum energy that an electron can gain in a non-linear density wave in a magnetised plasma, and we show that an electron can `surf' a sufficiently intense Born-Infeld electromagnetic plane wave and be strongly accelerated by the wave. The first result is valid for a large class of physically reasonable modifications of the linear Maxwell equations, whilst the second result exploits the special mathematical structure of Born-Infeld theory.

David A. Burton; Stephen P. Flood; Haibao Wen

2015-01-18T23:59:59.000Z

5

Non-perturbative aspects of particle acceleration in non-linear electrodynamics  

E-Print Network (OSTI)

We undertake an investigation of particle acceleration in the context of non-linear electrodynamics. We deduce the maximum energy that an electron can gain in a non-linear density wave in a magnetised plasma, and we show that an electron can `surf' a sufficiently intense Born-Infeld electromagnetic plane wave and be strongly accelerated by the wave. The first result is valid for a large class of physically reasonable modifications of the linear Maxwell equations, whilst the second result exploits the special mathematical structure of Born-Infeld theory.

Burton, David A; Wen, Haibao

2015-01-01T23:59:59.000Z

6

Focusing in Linear Accelerators  

DOE R&D Accomplishments (OSTI)

Review of the theory of focusing in linear accelerators with comments on the incompatibility of phase stability and first-order focusing in a simple accelerator.

McMillan, E. M.

1950-08-24T23:59:59.000Z

7

Fermilab | Science | Particle Accelerators  

NLE Websites -- All DOE Office Websites (Extended Search)

Particle Accelerators Main Injector As America's particle physics laboratory, Fermilab operates and builds powerful particle accelerators for investigating the smallest things...

8

History of Proton Linear Accelerators  

E-Print Network (OSTI)

much. References 1. Linear Accelerators, edited by P. M .at the 1986 Linear Accelerator Conference, SLAC, Stanford,HISTORY OF PROTON LINEAR ACCELERATORS Luis W. Alvarez TWO-

Alvarez, Luis W.

1987-01-01T23:59:59.000Z

9

North Linear Accelerator  

NLE Websites -- All DOE Office Websites (Extended Search)

North Linear Accelerator North Linear Accelerator Building Exterior Beam Enclosure Level Walk to the North Spreader North Recombiner Extras! North Linear Accelerator The North Linear Accelerator is one of the two long, straight sections of Jefferson Lab's accelerator. Electrons gain energy in this section by passing through acceleration cavities. There are 160 cavities in this straightaway, all lined up end to end. That's enough cavities to increase an electron's energy by 400 million volts each time it passes through this section. Electrons can pass though this section as many as five times! The cavities are powered by microwaves that travel down the skinny rectangular pipes from the service buildings above ground. Since the cavities won't work right unless they are kept very cold, they

10

Berkeley Proton Linear Accelerator  

DOE R&D Accomplishments (OSTI)

A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

1953-10-13T23:59:59.000Z

11

History of Proton Linear Accelerators  

E-Print Network (OSTI)

the board to show why the accelerator couldn't work. Then atmuch. References 1. Linear Accelerators, edited by P. M .at the 1986 Linear Accelerator Conference, SLAC, Stanford,

Alvarez, Luis W.

1986-01-01T23:59:59.000Z

12

Linear induction accelerator  

DOE Patents (OSTI)

A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.

Buttram, M.T.; Ginn, J.W.

1988-06-21T23:59:59.000Z

13

History of Proton Linear Accelerators  

DOE R&D Accomplishments (OSTI)

Some personal recollections are presented that relate to the author`s experience developing linear accelerators, particularly for protons. (LEW)

Alvarez, L. W.

1987-01-00T23:59:59.000Z

14

Repair of overheating linear accelerator  

SciTech Connect

Los Alamos Neutron Science Center (LANSCE) is a proton accelerator that produces high energy particle beams for experiments. These beams include neutrons and protons for diverse uses including radiography, isotope production, small feature study, lattice vibrations and material science. The Drift Tube Linear Accelerator (DTL) is the first portion of a half mile long linear section of accelerator that raises the beam energy from 750 keV to 100 MeV. In its 31st year of operation (2003), the DTL experienced serious issues. The first problem was the inability to maintain resonant frequency at full power. The second problem was increased occurrences of over-temperature failure of cooling hoses. These shortcomings led to an investigation during the 2003 yearly preventative maintenance shutdown that showed evidence of excessive heating: discolored interior tank walls and coper oxide deposition in the cooling circuits. Since overheating was suspected to be caused by compromised heat transfer, improving that was the focus of the repair effort. Investigations revealed copper oxide flow inhibition and iron oxide scale build up. Acid cleaning was implemented with careful attention to protection of the base metal, selection of components to clean and minimization of exposure times. The effort has been very successful in bringing the accelerator through a complete eight month run cycle allowing an incredible array of scientific experiments to be completed this year (2003-2004). This paper will describe the systems, investigation analysis, repair, return to production and conclusion.

Barkley, Walter; Baldwin, William; Bennett, Gloria; Bitteker, Leo; Borden, Michael; Casados, Jeff; Fitzgerald, Daniel; Gorman, Fred; Johnson, Kenneth; Kurennoy, Sergey; Martinez, Alberto; O’Hara, James; Perez, Edward; Roller, Brandon; Rybarcyk, Lawrence; Stark, Peter; Stockton, Jerry

2004-01-01T23:59:59.000Z

15

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

SciTech Connect

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

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

2012-06-26T23:59:59.000Z

16

Decay of accelerated particles  

Science Journals Connector (OSTI)

We study how the decay properties of particles are changed by acceleration. It is shown that under the influence of acceleration (1) the lifetime of particles is modified and (2) new processes (such as the decay of the proton) become possible. This is illustrated by considering scalar models for the decay of muons, pions, and protons. We discuss the close conceptual relation between these processes and the Unruh effect.

Rainer Müller

1997-07-15T23:59:59.000Z

17

Fermilab | Science | Particle Accelerators | Leading Accelerator...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fermilab scientists and engineers develop particle accelerators to produce beams to take particle physics to the next level, collaborating with scientists and...

18

Cast dielectric composite linear accelerator  

DOE Patents (OSTI)

A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

Sanders, David M. (Livermore, CA); Sampayan, Stephen (Manteca, CA); Slenes, Kirk (Albuquerque, NM); Stoller, H. M. (Albuquerque, NM)

2009-11-10T23:59:59.000Z

19

Independent Oversight Inspection, Stanford Linear Accelerator...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Stanford Linear Accelerator Center - January 2007 January 2007 Inspection of Environment, Safety, and Health Programs at the Stanford Linear Accelerator Center This report...

20

Laser Wakefield Particle Accelerators Project at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Wakefield Particle Acceleration Laser Wakefield Particle Acceleration Vorpal.jpg Key Challenges: Design of multiple-staged, 10-GeV laser-wakefield plasma accelerated...

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Acceleration-field calculation for a structure-based laser-driven linear accelerator  

E-Print Network (OSTI)

Acceleration-field calculation for a structure-based laser-driven linear accelerator Y. C. Huanga for publication 16 April 1998 A laser-driven particle accelerator, scaled to optical wavelengths, has a feature size many orders of magnitude smaller than a radio-frequency accelerator. However, similar to a radio

Byer, Robert L.

22

High field gradient particle accelerator  

DOE Patents (OSTI)

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

Nation, J.A.; Greenwald, S.

1989-05-30T23:59:59.000Z

23

High field gradient particle accelerator  

DOE Patents (OSTI)

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

Nation, John A. (Ithaca, NY); Greenwald, Shlomo (Haifa, IL)

1989-01-01T23:59:59.000Z

24

Ultra-high vacuum photoelectron linear accelerator  

DOE Patents (OSTI)

An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.

Yu, David U.L.; Luo, Yan

2013-07-16T23:59:59.000Z

25

Cryogenic technology boosts linear accelerator capability  

Science Journals Connector (OSTI)

Cryogenic technology boosts linear accelerator capability ... Two critical properties of matter at cryogenic temperatures—superconductivity and superfluidity—should open the way for a major advance in electron linear accelerator capability. ...

1968-05-06T23:59:59.000Z

26

Fermilab | Science | Particle Accelerators | Advanced Superconducting...  

NLE Websites -- All DOE Office Websites (Extended Search)

Superconducting Test Accelerator is America's only test bed for cutting-edge particle beams and for accelerator research aimed at Intensity Frontier proton accelerators. ASTA...

27

Voltage regulation in linear induction accelerators  

DOE Patents (OSTI)

Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance.

Parsons, William M. (Santa Fe, NM)

1992-01-01T23:59:59.000Z

28

Voltage regulation in linear induction accelerators  

DOE Patents (OSTI)

Improvement in voltage regulation in a linear induction accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core is disclosed. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance. 4 figs.

Parsons, W.M.

1992-12-29T23:59:59.000Z

29

ACCELERATION OF CHARGED PARTICLES  

Science Journals Connector (OSTI)

... similarity in its behaviour to that of a synchronous motor, he has called a 'synchroton'. It is shown that a particle, the energy of which (called its ' ...

1946-03-23T23:59:59.000Z

30

Optimization Online - Accelerated Linearized Bregman Method  

E-Print Network (OSTI)

Jun 27, 2011 ... Abstract: In this paper, we propose and analyze an accelerated linearized Bregman (ALB) method for solving the basis pursuit and related ...

Bo Huang

2011-06-27T23:59:59.000Z

31

Terahertz-driven linear electron acceleration  

E-Print Network (OSTI)

The cost, size and availability of electron accelerators is dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency (RF) accelerating structures operate with 30-50 MeV/m gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional RF structures. However, laser-driven electron accelerators require intense sources and suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here, we demonstrate the first linear acceleration of electrons with keV energy gain using optically-generated terahertz (THz) pulses. THz-driven accelerating structures enable high-gradient electron accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. Increasing the operational frequency of accelerators into the THz band allows for greatly increased accelerating ...

Nanni, Emilio Alessandro; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

2014-01-01T23:59:59.000Z

32

Cosmic Particle Acceleration: Basic Issues  

E-Print Network (OSTI)

Cosmic-rays are ubiquitous, but their origins are surprisingly difficult to understand. A review is presented of some of the basic issues common to cosmic particle accelerators and arguments leading to the likely importance of diffusive shock acceleration as a general explanation. The basic theory of diffusive shock acceleration is outlined, followed by a discussion of some of the key issues that still prevent us from a full understanding of its outcomes. Some recent insights are mentioned at the end that may help direct ultimate resolution of our uncertainties.

T. W. Jones

2000-12-22T23:59:59.000Z

33

Characterisation of electron beams from laser-driven particle accelerators  

SciTech Connect

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. [Physics Department, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2012-12-21T23:59:59.000Z

34

Particle acceleration in the heliosphere  

Science Journals Connector (OSTI)

The heliosphere is filled with supersonic solar wind that forms shocks wherever it encounters obstacles be they a high speed Coronal Mass Ejection (CME) or regions where fastsolar wind encounters slower-moving solar wind. Energetic particles (> 10s of keV/nuc to 10s of MeV/nuc) associated with these shocks form a test bed for understanding particle acceleration since the shock properties can often be measured and energetic particle composition compared to candidate seed populations. Over the past 15-20 years a wide body of evidence has emerged showing that generally the seed population is the suprathermal ion pool at energies above the bulk solar wind. Understanding the interplanetary suprathermal ion population is therefore a critical step in fully understanding the physical mechanisms that accelerate particles in interplanetary space.

G. M. Mason; M. I. Desai; R. A. Mewaldt; C. M. S. Cohen

2013-01-01T23:59:59.000Z

35

Independent Oversight Inspection, Stanford Linear Accelerator Center -  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Stanford Linear Accelerator Stanford Linear Accelerator Center - January 2007 Independent Oversight Inspection, Stanford Linear Accelerator Center - January 2007 January 2007 Inspection of Environment, Safety, and Health Programs at the Stanford Linear Accelerator Center The U.S. Department of Energy (DOE) Office of Independent Oversight, within the Office of Health, Safety and Security, conducted an inspection of environment, safety, and health (ES&H) programs at the DOE Stanford Linear Accelerator Center (SLAC) during October and November 2006. The inspection was performed by Independent Oversight's Office of Environment, Safety and Health Evaluations. Since the 2004 Type A electrical accident, SSO and SLAC have made improvements in many aspects of ES&H programs. However, the deficiencies in

36

High-gradient compact linear accelerator  

DOE Patents (OSTI)

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter.

Carder, Bruce M. (205 Rogue River Hwy., Gold Hill, OR 97525)

1998-01-01T23:59:59.000Z

37

High-gradient compact linear accelerator  

DOE Patents (OSTI)

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.

Carder, B.M.

1998-05-26T23:59:59.000Z

38

Radio-frequency quadrupole resonator for linear accelerator  

DOE Patents (OSTI)

An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

Moretti, A.

1982-10-19T23:59:59.000Z

39

Linear Accelerator | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

(MeV). At 450 MeV, the electrons are relativistic: they are traveling at >99.999% of the speed of light, which is 299,792,458 meters second (186,000 milessecond). Photo: Linear...

40

Fermilab | Science | Particle Accelerators | Fermilab's Accelerator...  

NLE Websites -- All DOE Office Websites (Extended Search)

It produces the world's most powerful, high-energy neutrino beam and provides proton beams for various experiments and R&D programs. Fermilab's accelerator complex delivers...

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources  

E-Print Network (OSTI)

essential understanding of accelerator physics to advanceof high- gradient, laser plasma particle accelerators.to conventional particle accelerators, plasmas can sustain

Geddes, Cameron G.R.

2010-01-01T23:59:59.000Z

42

How Particle Accelerators Work | Department of Energy  

Office of Environmental Management (EM)

or protons, to very high energies. On a basic level, particle accelerators produce beams of charged particles that can be used for a variety of research purposes. There are...

43

Enhanced dielectric-wall linear accelerator  

DOE Patents (OSTI)

A dielectric-wall linear accelerator is enhanced by a high-voltage, fast e-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 6 figs.

Sampayan, S.E.; Caporaso, G.J.; Kirbie, H.C.

1998-09-22T23:59:59.000Z

44

Particle accelerator employing transient space charge potentials  

DOE Patents (OSTI)

The invention provides an accelerator for ions and charged particles. The plasma is generated and confined in a magnetic mirror field. The electrons of the plasma are heated to high temperatures. A series of local coils are placed along the axis of the magnetic mirror field. As an ion or particle beam is directed along the axis in sequence the coils are rapidly pulsed creating a space charge to accelerate and focus the beam of ions or charged particles.

Post, Richard F. (Walnut Creek, CA)

1990-01-01T23:59:59.000Z

45

Advanced Modeling for Particle Accelerators Project at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Modeling for Particle Accelerators Advanced Modeling for Particle Accelerators HDX Key Challenges: Work in this area consists of both application development and...

46

Space Charge Compensation in Laser Particle Accelerators L.C...  

NLE Websites -- All DOE Office Websites (Extended Search)

Compensation in Laser Particle Accelerators L.C. Steinhauer and W.D. Kimura STI Optronics, 2755 Northup Way, Bellevue, WA 98004-1495 Abstract. Laser particle acceleration...

47

Solar Flares and particle acceleration  

E-Print Network (OSTI)

-free emission) #12;X-ray spectrum of solar flares Thermal X-rays Non-thermal X-rays Gamma-ray lines Ramaty High from Krucker et al, 2007 Solar flares are rapid localised brightening in the lower atmosphere. More particle Flaring region T ~ 4x107 K => 3 keV per particle Flare volume 1027 cm3 => (104 km)3 Plasma density

48

Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA  

SciTech Connect

In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a 'scaling' principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10?mm in radius over an electron momentum range of 12-18 MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators.

Machida, S.; Barlow, R.; Berg, J.S.; Bliss, N.; Buckley, R.K.; Clarke, J.A.; Craddock, M.K.; D'Arcy, R.; Edgecock, R.; Garland, J.M.; Giboudot, Y.; /Rutherford /Huddersfield U. /Brookhaven /Daresbury /Cockcroft Inst. Accel. Sci. Tech. /TRIUMF /British Columbia U., Vancouver, Dept. Phys. Astron. /University Coll. London /Manchester U. /Brunel U. /ASP, Melbourne

2012-03-01T23:59:59.000Z

49

The Klynac: An Integrated Klystron and Linear Accelerator  

SciTech Connect

The Klynac concept integrates an electron gun, a radio frequency (RF) power source, and a coupled-cavity linear accelerator into a single resonant system

Potter, J. M., Schwellenbach, D., Meidinger, A.

2012-08-07T23:59:59.000Z

50

An Accelerated Linearized Alternating Direction Method of Multipliers  

E-Print Network (OSTI)

Feb 12, 2014 ... An Accelerated Linearized Alternating Direction Method of Multipliers. Yuyuan Ouyang(ouyang ***at*** ufl.edu) Yunmei Chen(yun ***at*** ...

Yuyuan Ouyang

2014-02-12T23:59:59.000Z

51

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

2005-06-07T23:59:59.000Z

52

Seventy Five Years of Particle Accelerators  

ScienceCinema (OSTI)

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. His talk was presented July 26, 2006.

Andy Sessler

2013-06-11T23:59:59.000Z

53

Gerig to Chair Particle Accelerator School Board  

NLE Websites -- All DOE Office Websites (Extended Search)

A Record Run for the APS X-ray Source A Record Run for the APS X-ray Source Alp of XSD Elected to FIP Executive Committee George Srajer Appointed APS Upgrade Project Director Toby of XSD to Chair U.S. National Committee for Crystallography Controlling the Inner Electron Dance APS News Archives: 2012 | 2011 | 2010 | 2009 2008 | 2007 | 2006 | 2005 2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed Gerig to Chair Particle Accelerator School Board FEBRUARY 23, 2012 Bookmark and Share Rod Gerig (PSC), Deputy Associate Laboratory Director for Photon Sciences Rod Gerig was selected chair of the Board of Governors of the U.S. Particle Accelerator School (USPAS) at the board's annual meeting. Gerig is Deputy Associate Laboratory Director for Photon Sciences at Argonne National Laboratory, and is also the director of the Argonne Accelerator

54

Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources  

E-Print Network (OSTI)

of high- gradient, laser plasma particle accelerators.accelerators that use laser-driven plasma waves. Theseleft) showing the laser (red), plasma wake density (purple-

Geddes, Cameron G.R.

2010-01-01T23:59:59.000Z

55

Drift tube suspension for high intensity linear accelerators  

DOE Patents (OSTI)

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Liska, Donald J. (Los Alamos, NM); Schamaun, Roger G. (Los Alamos, NM); Clark, Donald C. (Los Alamos, NM); Potter, R. Christopher (Los Alamos, NM); Frank, Joseph A. (Los Alamos, NM)

1982-01-01T23:59:59.000Z

56

Drift tube suspension for high intensity linear accelerators  

DOE Patents (OSTI)

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.

1980-03-11T23:59:59.000Z

57

Variable-energy drift-tube linear accelerator  

DOE Patents (OSTI)

A linear accelerator system includes a plurality of post-coupled drift-tubes wherein each post coupler is bistably positionable to either of two positions which result in different field distributions. With binary control over a plurality of post couplers, a significant accumlative effect in the resulting field distribution is achieved yielding a variable-energy drift-tube linear accelerator.

Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM); Potter, James M. (Los Alamos, NM); Stovall, James E. (Los Alamos, NM)

1984-01-01T23:59:59.000Z

58

Solving radiation problems at particle accelerators  

SciTech Connect

At high-intensity high-energy particle accelerators, consequences of a beam-induced radiation impact on machine and detector components, people, environment and complex performance can range from negligible to severe. The specifics, general approach and tools used at such machines for radiation analysis are described. In particular, the world leader Fermilab accelerator complex is considered, with its fixed target and collider experiments, as well as new challenging projects such as LHC, VLHC, muon collider and neutrino factory. The emphasis is on mitigation of deleterious beam-induced radiation effects and on the key role of effective computer simulations.

Nikolai V. Mokhov

2001-12-11T23:59:59.000Z

59

Self-force on an accelerated particle  

Science Journals Connector (OSTI)

We calculate the singular field of an accelerated point particle (scalar charge, electric charge or small gravitating mass) moving on an accelerated (nongeodesic) trajectory in a generic background spacetime. Using a mode-sum regularization scheme, we obtain explicit expressions for the self-force regularization parameters. We use a Lorentz gauge for the electromangetic and gravitational cases. This work extends the work of Barack and Ori [1] who demonstrated that the regularization parameters for a point particle in geodesic motion in a Schwarzschild spacetime can be described solely by the leading and subleading terms in the mode-sum (commonly known as the A and B terms) and that all terms of higher order in ? vanish upon summation (later they showed the same behavior for geodesic motion in Kerr [2], [3]). We demonstrate that these properties are universal to point particles moving through any smooth spacetime along arbitrary (accelerated) trajectories. Our renormalization scheme is based on, but not identical to, the Quinn-Wald axioms. As we develop our approach, we review and extend work showing that that different definitions of the singular field used in the literature are equivalent to our approach. Because our approach does not assume geodesic motion of the perturbing particle, we are able use our mode-sum formalism to explicitly recover a well-known result: The self-force on static scalar charges near a Schwarzschild black hole vanishes.

Thomas M. Linz; John L. Friedman; Alan G. Wiseman

2014-07-23T23:59:59.000Z

60

Detecting chaos in particle accelerators through the frequency map analysis method  

E-Print Network (OSTI)

The motion of beams in particle accelerators is dominated by a plethora of non-linear effects which can enhance chaotic motion and limit their performance. The application of advanced non-linear dynamics methods for detecting and correcting these effects and thereby increasing the region of beam stability plays an essential role during the accelerator design phase but also their operation. After describing the nature of non-linear effects and their impact on performance parameters of different particle accelerator categories, the theory of non-linear particle motion is outlined. The recent developments on the methods employed for the analysis of chaotic beam motion are detailed. In particular, the ability of the frequency map analysis method to detect chaotic motion and guide the correction of non-linear effects is demonstrated in particle tracking simulations but also experimental data.

Yannis Papaphilippou

2014-06-05T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Neutron Sciences Staff Give Back, Teach US Particle Accelerator...  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Sciences Staff Give Back, Teach US Particle Accelerator School Courses Katie Bethea - March 13, 2014 Neutron Science Directorate staff hosted students from the US Particle...

62

STANFORD LINEAR ACCELERATOR CENTER Stanford University  

E-Print Network (OSTI)

particle beams, and we look forward to interesting results on plasma focusing. Best personal regards

63

E-Print Network 3.0 - acceleration linear collider Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

PARTICLES Electrons can be produced by Summary: is invariant Many current particle accelerators are used to collide high energy particle beams. The majority... of accelerators are...

64

Novel Approach to Linear Accelerator Superconducting Magnet System  

SciTech Connect

Superconducting Linear Accelerators include a superconducting magnet system for particle beam transportation that provides the beam focusing and steering. This system consists of a large number of quadrupole magnets and dipole correctors mounted inside or between cryomodules with SCRF cavities. Each magnet has current leads and powered from its own power supply. The paper proposes a novel approach to magnet powering based on using superconducting persistent current switches. A group of magnets is powered from the same power supply through the common, for the group of cryomodules, electrical bus and pair of current leads. Superconducting switches direct the current to the chosen magnet and close the circuit providing the magnet operation in a persistent current mode. Two persistent current switches were fabricated and tested. In the paper also presented the results of magnetic field simulations, decay time constants analysis, and a way of improving quadrupole magnetic center stability. Such approach substantially reduces the magnet system cost and increases the reliability.

Kashikhin, Vladimir; /Fermilab

2011-11-28T23:59:59.000Z

65

Technical Challenges and Scientific Payoffs of Muon Beam Accelerators for Particle Physics  

E-Print Network (OSTI)

of 2006 European Particle Accelerator Conf. , Edinburgh,Proc. 1992 European Particle Accelerator Conference, Berlin,in Proc. 2007 Particle Accelerator Conf. , Albuquerque, June

Zisman, Michael S.

2008-01-01T23:59:59.000Z

66

Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators  

SciTech Connect

Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.

V.S. Morozov, S.A. Bogacz, Y.R. Roblin, K.B. Beard

2012-06-01T23:59:59.000Z

67

Particle acceleration in relativistic subluminal shock environments  

E-Print Network (OSTI)

The understanding of the particle spectra resulting from acceleration in relativistic shocks as they occur in extragalactic sources, is essential for the interpretation of the cosmic ray spectrum above the ankle ($E_p>3\\cdot 10^{18}$ eV). It is believed that extragalactic sources like Active Galactic Nuclei and Gamma Ray Bursts can produce particle spectra up to $E_p\\sim 10^{21}$ eV. In this contribution, subluminal shocks are investigated with respect to different shock boost factors $\\Gamma$ and the inclination angle between the shock normal and the magnetic field $\\psi$. A correlation between the boost factor and the spectral behavior of the emitted particles is found. The results are compared to Active Galactic Nuclei and Gamma Ray Burst diffuse cosmic ray contribution and the observed cosmic ray spectrum at the highest energies.

A. Meli; J. Becker; J. J. Quenby; J. Luenemann

2007-08-10T23:59:59.000Z

68

Linear Accelerators for Protons: New Developments  

Science Journals Connector (OSTI)

...5 P INT C HIGH EN AC 624 ( 1965 ). CITRON, A, 1966 P LIN AC C 497 ( 1966 ). COURANT, E.D., THE STRONG-FOCUSING SYNCHROTON - A NEW HIGH ENERGY ACCELERATOR, PHYSICAL REVIEW 88 : 1190 ( 1952 ). CURTIS, C.D., 1966 P LIN ACC C 365 ( 1966...

Darragh E. Nagle

1967-07-14T23:59:59.000Z

69

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron  

E-Print Network (OSTI)

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre of the Helmholtz Association ACCELERATOR RESEARCH· DESY, Hamburg location, is seeking: Senior Scientist (f/m) Accelerator Research DESY DESY is one of the world's leading research centres for photon science, particle

70

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron  

E-Print Network (OSTI)

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre of the Helmholtz Association ACCELERATOR RESEARCH· DESY, Hamburg location, is seeking: Scientist (f/m) Tenure Track physics as well as accelerator physics. Accelerator research at DESY in Hamburg, Germany, is being

71

The Klynac: An Integrated Klystron and Linear Accelerator  

SciTech Connect

The Klynac concept integrates an electron gun, a radio frequency (RF) power source, and a coupled-cavity linear accelerator into a single resonant system. The klystron is essentially a conventional klystron structure with an input cavity, some number of intermediate cavities and an output cavity. The accelerator structure is, likewise, a conventional on-axis coupled structure. The uniqueness is the means of coupling the klystron output cavity to the accelerator. The coupler is a resonant coupler rather than an ordinary transmission line. The geometry of such a system need not be coaxial. However, if the klystron and accelerator are coaxial we can eliminate the need for a separate cathode for the accelerator by injecting some of the klystron beam into the accelerator. Such a device can be made cylindrical which is ideal for some applications.

Potter, J. M. [JP Accelerator Works; Schwellenbach, D. [NSTec

2013-04-01T23:59:59.000Z

72

Application of particle accelerators in research  

Science Journals Connector (OSTI)

......prospectives is presented. Accelerators in research are widely...to solid state, nuclear and atomic physics...bunches-multi bunch accelerator) and decrease the...In a multi-bunch accelerator, separate vacuum chambers are needed......

Giovanni Mazzitelli

2011-07-01T23:59:59.000Z

73

uge particle accelerators have been at the vanguard of research in particle  

E-Print Network (OSTI)

H uge particle accelerators have been at the vanguard of research in particle physics for more than to develop new and more compact accelerator technologies. Threereports1­3 inthisissue(frompage535) announce counterparts, positrons, can then `surf' the electric field of a wave's wake. Particles have been accelerated

Geddes, Cameron Guy Robinson

74

Grad student aims to improve particle accelerators > EMC2 News...  

NLE Websites -- All DOE Office Websites (Extended Search)

Grad student aims to improve particle accelerators August 6th, 2014 By Linda B. Glaser Lindsay FranceUniversity Photography Siddharth Karkare, left, and Laurent Boulet '14 in...

75

New Science on the Horizon as Upgraded Particle Accelerator Meets...  

Office of Science (SC) Website

New Science on the Horizon as Upgraded Particle Accelerator Meets Commissioning Milestones Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP...

76

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron  

E-Print Network (OSTI)

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre and astroparticle physics as well as accelerator physics. The Photo Injector Test Facility PITZ in Zeuthen (near XFEL. As part of the accelerator R&D program of the Helmholtz Association the focus of the research

77

Acceleration of low energy charged particles by gravitational waves  

E-Print Network (OSTI)

The acceleration of charged particles in the presence of a magnetic field and gravitational waves is under consideration. It is shown that the weak gravitational waves can cause the acceleration of low energy particles under appropriate conditions. Such conditions may be satisfied close to the source of the gravitational waves if the magnetized plasma is in a turbulent state.

G. Voyatzis; L. Vlahos; S. Ichtiaroglou; D. Papadopoulos

2005-12-07T23:59:59.000Z

78

Particle acceleration in double radio sources  

Science Journals Connector (OSTI)

Further study has been made of a model of extragalactic double radio sources in which the magnetized accretion disc of a massive black hole acts as an electric dynamo producing oppositely directed beams of relativistic particles. An empty region of small angular size—a vortice core—is shown to be a possible consequence of the hydrodynamics of accretion of gas with angular momentum. An ambient magnetic field in the gas tends to accumulate in the core region. The acceleration of electrons in the dynamo electric field gives rise to oppositely directed electron beams which in turn produce synchroton gamma rays collimated along the core. Collisions between the gamma rays and low energy photons caN initiate an electromagnetic cascade shower. The cascade acts to produce a collimated relativistic electron?positron beam. If the current flow in the dynamo occurs in surges then the outward propagation of the head of the electron–positron beams may produce expanding compact radio components. The electron–positron beam is ballistic in nature and it is electrically neutral and carries no current. Such a beam appears to have favorable stability properties. The beam is eventually stopped and spread out in pitch angle by the ram pressure of the external medium. Synchrotron radiated lobes of double radio sources.

R. V. E. Lovelace; J. MacAuslan; M. Burns

1979-01-01T23:59:59.000Z

79

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

DOE Patents (OSTI)

A novel apparatus and method for focussing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The quadrupole arrays may comprise electrodes which are shared by two or more quadrupoles. Such quadrupole arrays are particularly adapted to providing strong focussing forces for high current, high brightness, beams of charged particles, said beams further comprising a plurality of parallel beams, or beamlets, each such beamlet being focussed by one quadrupole of the array. Such arrays may be incorporated in various devices wherein beams of charged particles are accelerated or transported, such as linear accelerators, klystron tubes, beam transport lines, etc.

Maschke, Alfred W. (East Moriches, NY)

1983-07-05T23:59:59.000Z

80

A particle accelerator employing transient space charge potentials  

DOE Patents (OSTI)

The invention provides an accelerator for ions and charged particles. The plasma is generated and confined in a magnetic mirror field. The electrons of the plasma are heated to high temperatures. A series of local coils are placed along the axis of the magnetic mirror field. As an ion or particle beam is directed along the axis in sequence the coils are rapidly pulsed creating a space charge to accelerate and focus the beam of ions or charged particles. 3 figs.

Post, R.F.

1988-02-25T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

In-Situ Monitoring of Particle Growth at PEMFC Cathode under Accelerated Cycling Conditions  

SciTech Connect

An in-situ method to measure changes in catalyst particle size at the cathode of a proton exchange membrane fuel cell is demonstrated. Synchrotron X-rays, 58 keV, were used to measure the pair distribution function on an operating fuel cell and observe the growth of catalyst particles under accelerated degradation conditions. The stability of Pt/C and PtCo/C with different initial particle sizes was monitored over 3000 potential cycles. The increase in particle size was fit to a linear trend as a function of cycles. The most stable electrocatalyst was found to be the alloyed PtCo with the larger initial particle size.

Billinge S. J.; Redmond, E.L.; Setzler, B.P.; Juhas, P.; Fullera, T.F.

2012-05-01T23:59:59.000Z

82

In-Situ Monitoring of Particle Growth at PEMFC Cathode under Accelerated Cycling Conditions  

SciTech Connect

An in-situ method to measure changes in catalyst particle size at the cathode of a proton exchange membrane fuel cell is demonstrated. Synchrotron X-rays, 58 keV, were used to measure the pair distribution function on an operating fuel cell and observe the growth of catalyst particles under accelerated degradation conditions. The stability of Pt/C and PtCo/C with different initial particle sizes was monitored over 3000 potential cycles. The increase in particle size was fit to a linear trend as a function of cycles. The most stable electrocatalyst was found to be the alloyed PtCo with the larger initial particle size.

Redmond, Erin L.; Setzler, Brian P.; Juhas, Pavol; Billinge, Simon J.L.; Fuller, Thomas F. (GIT); (Columbia)

2012-10-25T23:59:59.000Z

83

Particle Physics and Astrophysics : SLAC National Accelerator...  

NLE Websites -- All DOE Office Websites (Extended Search)

scientists use accelerators which speed electrons and anti-electrons to nearly the speed of light, and study their collisions and collisions from fixed target experiments....

84

Numerical study on charged particle accelerations in the plasma focus  

Science Journals Connector (OSTI)

Collective features of accelerated ions in the plasma focus are investigated theoretically by using a computer simulation. It is shown that an effective heating of ions by the acceleration of ions occurs without collisions in the collapse phase. A hybrid plasma diode model is used for the particle accelerations after disruption of the focused plasma by the m=0 mode instability. It is shown that ions are efficiently accelerated in the disrupted region toward the downstream direction with respect to the discharge current and that the energy of the accelerated ions is spread rather widely over the scale of 100 keV as was observed in experiments.

Yoshiomi Kondoh; Minoru Mamada

1986-01-01T23:59:59.000Z

85

Polarized electrons at the Bates Linear Accelerator Center  

SciTech Connect

A beam of polarized electrons have successfully been injected into the MIT Bates Linear Accelerator and accelerated it to 250 MeV. The intense beam was produced by photoemission from a GaAs crystal. The electron polarization at full energy, as measured by a brief test based on Moller scattering from a magnetized foil, was in excess of 30%. The peak intensity for the 15 ..mu..sec long pulses during the first test was about 2mA, representing about a third of the design value. The pulse rate of the accelerator was reduced to 60 Hz to minimize the total beam on the iron target. In a subsequent test, in which the beam hit a thick carbon target, the facility operated successfully at the full rate of 600 Hz. Under this condition, the average current on target was about 10 ..mu..A.

Souder, P.A.; Kim, D.H.; Kumar, K.; Schulze, M.; Lubell, M.; Patch, J.S.; Wilson, R.; Dodson, G.W.; Dow, K.A.; Flanz, J.

1986-01-01T23:59:59.000Z

86

Linear induction accelerator and pulse forming networks therefor  

DOE Patents (OSTI)

A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities.

Buttram, Malcolm T. (Sandia Park, NM); Ginn, Jerry W. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

87

Superstructure for high current applications in superconducting linear accelerators  

DOE Patents (OSTI)

A superstructure for accelerating charged particles at relativistic speeds. The superstructure consists of two weakly coupled multi-cell subunits equipped with HOM couplers. A beam pipe connects the subunits and an HOM damper is included at the entrance and the exit of each of the subunits. A coupling device feeds rf power into the subunits. The subunits are constructed of niobium and maintained at cryogenic temperatures. The length of the beam pipe between the subunits is selected to provide synchronism between particles and rf fields in both subunits.

Sekutowicz, Jacek (Elbchaussee, DE); Kneisel, Peter (Williamsburg, VA)

2008-03-18T23:59:59.000Z

88

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

ScienceCinema (OSTI)

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

2011-04-28T23:59:59.000Z

89

Accelerated Iterative Method for Solving Steady Solutions of Linearized Atmospheric Models  

E-Print Network (OSTI)

Accelerated Iterative Method for Solving Steady Solutions of Linearized Atmospheric Models Masahiro approach, referred to as the accelerated iterative method (AIM), is developed for solving steady state, respectively. For ensuring the accelerated asymptotic convergence of iterative procedure

Watanabe, Masahiro

90

A comparative study of the peripheral doses from a linear accelerator with a multileaf collimator system  

Science Journals Connector (OSTI)

......Oncor Impression linear accelerator on its 6-MV photon...libraries (Evaluated Nuclear Data Files, version...The head included the vacuum envelope assembly for...photon beams on a linear accelerator with multileaf collimator...Peripheral dose from a linear accelerator equipped with multileaf......

Hediye Acun; Ali Zubaroglu; Gönül Kemikler; Ahmet Bozkurt

2014-02-01T23:59:59.000Z

91

Thermal Particle Injection in Nonlinear Diffusive Shock Acceleration  

E-Print Network (OSTI)

Particle acceleration in collisionless astrophysical shocks, i.e., diffusive shock acceleration (DSA), is the most likely mechanism for producing cosmic rays, at least below 10^{15} eV. Despite the success of this theory, several key elements, including the injection of thermal particles, remains poorly understood. We investigate injection in strongly nonlinear shocks by comparing a semi-analytic model of DSA with a Monte Carlo model. These two models treat injection quite differently and we show, for a particular set of parameters, how these differences influence the overall acceleration efficiency and the shape of the broad-band distribution function.

Donald C. Ellison; Pasquale Blasi; Stefano Gabici

2005-07-05T23:59:59.000Z

92

E-Print Network 3.0 - aps linear accelerator Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Collection: Computer Technologies and Information Sciences 6 Particle acceleration in solar flares: observations versus numerical simulations Summary: of stochastic electron...

93

Magnetic reconnection configurations and particle acceleration in solar flares  

E-Print Network (OSTI)

types of solar flares. Upper panel: two-ribbon flares; Lower panel: compact flares. The color showsMagnetic reconnection configurations and particle acceleration in solar flares P. F. Chen, W. J space under different magnetic configurations. Key words: solar flares, magnetic reconnection, particle

Chen, P. F.

94

RECENT PROGRESS TOWARD A MUON RECIRCULATING LINEAR ACCELERATOR  

SciTech Connect

Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchnotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadruopoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.

Slawomir Bogacz, Vasiliy Morozov, Yves Roblin, Kevin Beard

2012-07-01T23:59:59.000Z

95

First order particle acceleration in magnetically-driven flows  

E-Print Network (OSTI)

We demonstrate that particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. Some examples of such flows include spontaneous turbulent reconnection and decaying magnetohydrodynamic (MHD) turbulence, where magnetic field relaxes to a lower-energy configuration and transfers part of its energy to kinetic motions. The opposite process, such as dynamo, will actually result in the net cooling of particles by the curvature drift. Being very generic, this acceleration mechanism is likely to be responsible in production of non-thermal particle distribution in magnetically-dominant environments such as solar chromosphere, pulsar magnetosphere, jets from supermassive black holes, $\\gamma$-ray bursts, etc.

Beresnyak, Andrey

2014-01-01T23:59:59.000Z

96

Reversed Gravitational Acceleration for High-speed Particles  

E-Print Network (OSTI)

Examination of the free-fall motion of particles of extremely high-speed in the Schwarzschild geometry reveals that the gravitational acceleration of such particles is reversed when measured in Schwarzschild coordinates. High-speed particles decelerate when moving radially downward, and they accelerate when moving upward. The onset of this abnormal behavior occurs at a speed of 1/Sqrt(3) times the local value of the speed of light. However, the gravitational force always remains attractive. PACS numbers: 04.20.-q, 04.20.Cv, 01.65+g

Hans C. Ohanian

2011-02-14T23:59:59.000Z

97

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)

1993-11-01T23:59:59.000Z

98

Energetic particle acceleration at corotating interaction regions: Ulysses results  

SciTech Connect

We present here statistical properties of energetic ions (tilde 1 MeV) accelerated by corotating interaction regions observed at the Ulysses spacecraft. We have correlated the tilde 1 MeV proton intensity measured near the trailing edges of the interaction regions with their compression ratio. We interpret our results in terms of the plasma conditions experienced at Ulysses and identify a likely source of the low energy seed particles accelerated at the interaction regions.

Desai, M.I.; Marsden, R.G.; Sanderson, T.R. [ESTEC/ESA, Noordwijk (Netherlands). Space Science Dept.; Balogh, A.; Forsyth, R.J. [Imperial Coll., London (United Kingdom). Blackett Lab.; Gosling, J.T. [Los Alamos National Lab., NM (United States)

1997-07-01T23:59:59.000Z

99

Pulse Transformer Design for Magnet Powering in Particle Accelerators  

E-Print Network (OSTI)

This paper presents an optimal design procedure for pulse transformers fed by power converters for supplying pulsed current magnets in particle accelerators. Usually their volume must be minimized because of limited space available in the accelerator tunnel. Analytical and numerical models are presented as well as an experimental validation and a real case study where the design tool is exploited to derive a wide variety of solutions depending on the pulse transformers location with respect to the magnet position.

Aguglia, D

2014-01-01T23:59:59.000Z

100

Particle Energy And Acceleration Efficiencies In Highly Relativistic Shocks  

E-Print Network (OSTI)

In this paper we present an investigation of numerical Monte Carlo simulations of the diffusive shock acceleration in the test particle limit. Very high gamma flow astrophysical plasmas, have been used, from $\\gamma_{up}$ $\\sim50$ up to $\\gamma_{up}$ $\\sim1000$, which could be relevant to the suggested models of AGNs Jets and their Central Engines as well as the ultra-relativistic shock particle acceleration in Gamma Ray Burst (GRB) fireballs. Particularly the energy gain per shock crossing and the time constant for the above high relativistic processes is numerically calculated. We explicitly find a considerable $\\gamma^{2}$ energy boosting in the first shock cycle, and in all subsequent shock cycles the particle energy is multiplied by a large factor. Also a noted acceleration speed-up for the same acceleration process has been observed. Both of those results are connected with theoretical suggestions that a significant enhancement of the acceleration process is possible due to relativistic effects not present at lower plasma flow speeds. The acceleration speed-up and the mean energy-gain per shock cycle found could efficiently justify the theory of the origin of Ultra High Energy Cosmic Rays (UHECR) from the sites of GRBs.

A. Meli; J. J. Quenby

2001-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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101

Spinning Black Holes as Particle Accelerators  

Science Journals Connector (OSTI)

It has recently been pointed out that particles falling freely from rest at infinity outside a Kerr black hole can in principle collide with an arbitrarily high center of mass energy in the limiting case of maximal black hole spin. Here we aim to elucidate the mechanism for this fascinating result, and to point out its practical limitations, which imply that ultraenergetic collisions cannot occur near black holes in nature.

Ted Jacobson and Thomas P. Sotiriou

2010-01-14T23:59:59.000Z

102

Cyclotron resonant interactions in cosmic particle accelerators  

E-Print Network (OSTI)

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

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

2012-01-01T23:59:59.000Z

103

Stochastic particle acceleration and statistical closures  

SciTech Connect

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

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

1985-10-01T23:59:59.000Z

104

Cryogen free superconducting splittable quadrupole magnet for linear accelerators  

SciTech Connect

A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.

Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab

2011-09-01T23:59:59.000Z

105

Seminar Ia, cetrti letnik, stari program LONGITUDINAL DYNAMICS OF PARTICLES IN ACCELERATORS  

E-Print Network (OSTI)

Seminar Ia, cetrti letnik, stari program LONGITUDINAL DYNAMICS OF PARTICLES IN ACCELERATORS Author motion of charged particles in particle accelerators. The technique of acceleration by electromagnetic waves is explored and the stability of motion under such acceleration is inspected. The seminar

Â?umer, Slobodan

106

Particle Acceleration at Corotating Interaction Regions in the Heliosphere  

Science Journals Connector (OSTI)

Hybrid simulations are performed to investigate the dynamics of both solar wind protons and interplanetary pickup ions (PUIs) around the corotating interaction region (CIR). The one-dimensional system is applied in order to focus on processes in the direction of CIR propagation. The CIR is bounded by forward and reverse shocks, which are responsible for particle acceleration. The effective acceleration of solar wind protons takes place when the reverse shock (fast wind side) favors a quasi-parallel regime. The diffusive process accounts for this acceleration, and particles can gain energy in a suprathermal range (on the order of 10 keV). In contrast, the PUI acceleration around the shock differs from the conventional model in which the motional electric field along the shock surface accelerates particles. Owing to their large gyroradius, PUIs can gyrate between the upstream and downstream, several proton inertial lengths away from the shock. This "cross-shock" gyration results in a net velocity increase in the field-aligned component, indicating that the magnetic mirror force is responsible for acceleration. The PUIs that remain in the vicinity of the shock for a long duration (tens of gyroperiods) gain much energy and are reflected back toward the upstream. These reflected energetic PUIs move back and forth along the magnetic field between a pair of CIRs that are magnetically connected. The PUIs are repeatedly accelerated in each reflection, leading to a maximum energy gain close to 100 keV. This mechanism can be evaluated in terms of "preacceleration" for the generation of anomalous cosmic rays.

K. Tsubouchi

2014-01-01T23:59:59.000Z

107

Accurate and efficient spin integration for particle accelerators  

E-Print Network (OSTI)

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

Abell, Dan T; Ranjbar, Vahid H; Barber, Desmond P

2015-01-01T23:59:59.000Z

108

2011 Annual Planning Summary for Stanford Linear Accelerator Center Site Office (SLAC)  

Energy.gov (U.S. Department of Energy (DOE))

The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2011 and 2012 within the Stanford Linear Accelerator Center Site Office (SLAC SO) (See also Science).

109

Particle acceleration in the colliding winds binary WR140  

E-Print Network (OSTI)

Massive WR+O star systems produce high-temperature, shock-heated plasma where the wind of the WR star and that of its binary companion collide - the wind-collision region (WCR). The WCR is a source of thermal (e.g. hard X-rays) and non-thermal (e.g. synchrotron) emission, the latter arising from electrons and ions accelerated to relativistic energies. These colliding wind binaries provide an excellent laboratory for the study of particle acceleration at higher mass, photon and magnetic energy densities than exist in SNRs. Recent models of the non-thermal emission from WR 140 have provided insight into this process.

J. M. Pittard; S. M. Dougherty

2007-03-23T23:59:59.000Z

110

RESEARCH ON HIGH BEAM-CURRENT ACCELERATORS  

E-Print Network (OSTI)

and M. Wilson, Particle Accelerators 10, 223 13. A. I.Proc. 1976 Proton Linear Accelerator Conf. , Chalk River,and D. Keefe, Particle Accelerators~' 23. S. Humphries, J.

Keefe, Denis

2014-01-01T23:59:59.000Z

111

Environmental Survey preliminary report, Stanford Linear Accelerator Center, Stanford, California  

SciTech Connect

This report presents the preliminary findings from the first phase of the Survey of the US Department of Energy (DOE) Stanford Linear Accelerator Center (SLAC) at Stanford, California, conducted February 29 through March 4, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the SLAC. The Survey covers all environmental media and all areas of environmental regulation and is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations at the SLAC, and interviews with site personnel. The Survey team is developing a Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by a DOE National Laboratory or a support contractor. When completed, the results will be incorporated into the Environmental Survey Interim Report for the SLAC facility. The Interim Report will reflect the final determinations of the SLAC Survey. 95 refs., 25 figs., 25 tabs.

Not Available

1988-07-01T23:59:59.000Z

112

Application to Particle Accelerator Beam Stabilization Glenn Decker  

NLE Websites -- All DOE Office Websites (Extended Search)

the the Measurement of Noise with Application to Particle Accelerator Beam Stabilization Glenn Decker Advanced Photon Source Accelerator Systems Division December 1998 LS-273 1 1.0 Introduction One of the most important figures of merit for a synchrotron radiation source, once speci- fied beam intensity and energy have been achieved, is charged particle beam stability. While a sig- nificant effort has been expended at the Advanced Photon Source (APS) to reduce or eliminate undesirable sources of beam motion, it will be necessary to employ active feedback to stabilize the user photon beams to the very stringent levels required. This becomes especially important when one considers that transverse beam stability is generally quoted as a fraction of beam dimensions. Since source brightness tends to be inversely proportional to these transverse dimen-

113

CONSTRAINTS ON LASER-DRIVEN ACCELERATORS FOR A HIGH-ENERGY LINEAR COLLIDER*  

E-Print Network (OSTI)

CONSTRAINTS ON LASER-DRIVEN ACCELERATORS FOR A HIGH-ENERGY LINEAR COLLIDER* J.S. Wurtele and AV on 1 TeV) are applied to free-space laser and laser/plasma accelerators. It is shown that the requirements impose very severe constraints upon the new accelerators-- so severe, that it seems unlikely

Wurtele, Jonathan

114

Development of an RF Conditioning System for Charged-Particle Accelerators  

SciTech Connect

Charged-particle accelerators use various vacuum windows on their accelerating radio-frequency (RF) cavities to throughput very high RF power. Before being placed on the cavities, the windows should be cleaned, baked, and fully RF conditioned to prevent a poor vacuum from outgassing, as well as other forms of contamination. An example is the coaxial fundamental power coupler (FPC) with an annular alumina ceramic window for each of the 81 superconducting RF cavities in the Spallation Neutron Source (SNS) linear accelerator. The FPCs needed to be tested up to 650-kW peak in a traveling wave and 2.6 MW with standing wave peaks in 1.3 and 60 pulses/s at 805 MHz. In this paper, an Experimental-Physics-and-Industrial-Control-System-based RF conditioning system for the SNS RF test facility is presented. This paper summarizes the hardware and software design strategies, provides the results obtained, and describes the future research scope.

Kang, Yoon W [ORNL; Howlader, Mostofa [ORNL; Shajedul Hasan, Dr. S. M. [Virginia Polytechnic Institute and State University (Virginia Tech)

2008-01-01T23:59:59.000Z

115

Effects of diesel particle filter retrofits and accelerated fleet turnover  

NLE Websites -- All DOE Office Websites (Extended Search)

Effects of diesel particle filter retrofits and accelerated fleet turnover Effects of diesel particle filter retrofits and accelerated fleet turnover on drayage truck emissions at the port of Oakland Title Effects of diesel particle filter retrofits and accelerated fleet turnover on drayage truck emissions at the port of Oakland Publication Type Journal Article Year of Publication 2011 Authors Dallmann, Timothy R., Robert A. Harley, and Thomas W. Kirchstetter Journal Environmental Science & Technology Volume 45 Issue 24 Pagination 10773-10779 Abstract Heavy-duty diesel drayage trucks have a disproportionate impact on the air quality of communities surrounding major freight-handling facilities. In an attempt to mitigate this impact, the state of California has mandated new emission control requirements for drayage trucks accessing ports and rail yards in the state beginning in 2010. This control rule prompted an accelerated diesel particle filter (DPF) retrofit and truck replacement program at the Port of Oakland. The impact of this program was evaluated by measuring emission factor distributions for diesel trucks operating at the Port of Oakland prior to and following the implementation of the emission control rule. Emission factors for black carbon (BC) and oxides of nitrogen (NOx) were quantified in terms of grams of pollutant emitted per kilogram of fuel burned using a carbon balance method. Concentrations of these species along with carbon dioxide were measured in the exhaust plumes of individual diesel trucks as they drove by en route to the Port. A comparison of emissions measured before and after the implementation of the truck retrofit/replacement rule shows a 54 ± 11% reduction in the fleet-average BC emission factor, accompanied by a shift to a more highly skewed emission factor distribution. Although only particulate matter mass reductions were required in the first year of the program, a significant reduction in the fleet-average NOx emission factor (41 ± 5%) was observed, most likely due to the replacement of older trucks with new ones.

116

Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications  

SciTech Connect

Project Title: Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications PI: Michael R. Brown, Swarthmore College The purpose of the project was to provide theoretical and modeling support to the Swarthmore Spheromak Experiment (SSX). Accordingly, the theoretical effort was tightly integrated into the SSX experimental effort. During the grant period, Michael Brown and his experimental collaborators at Swarthmore, with assistance from W. Matthaeus as appropriate, made substantial progress in understanding the physics SSX plasmas.

Brown, Michael R.

2006-11-16T23:59:59.000Z

117

Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism  

E-Print Network (OSTI)

Electron acceleration to non-thermal energies in low Mach number (Msolar flares, but the electron acceleration mechanism remains poorly understood. Diffusive shock acceleration, also known as first-order Fermi acceleration, cannot be directly invoked to explain the acceleration of electrons. Rather, an additional mechanism is required to pre-accelerate the electrons from thermal to supra-thermal energies, so they can then participate in the Fermi process. In this work, we use two- and three-dimensional particle-in-cell plasma simulations to study electron acceleration in low Mach number shocks. We focus on the particle energy spectra and the acceleration mechanism in a reference run with M=3. We find that about 15 percent of the electrons can be efficiently accelerated, forming a non-thermal power-law tail in the energy spectrum with a slope of p~2.4. Initially, thermal electrons are energized at the shock front via shock drift a...

Guo, Xinyi; Narayan, Ramesh

2014-01-01T23:59:59.000Z

118

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

2008-01-01T23:59:59.000Z

119

2010 Annual Planning Summary for Stanford Linear Accelerator...  

Office of Environmental Management (EM)

Accelerator Center Site Office (SLAC) Annual Planning Summaries briefly describe the status of ongoing NEPA compliance activities, any EAs expected to be prepared in the next 12...

120

Photo of the Week: What Does a Particle Accelerator Have in Common with  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

What Does a Particle Accelerator Have in Common What Does a Particle Accelerator Have in Common with Your Thanksgiving Turkey? Photo of the Week: What Does a Particle Accelerator Have in Common with Your Thanksgiving Turkey? November 16, 2012 - 4:02pm Addthis At the SLAC National Accelerator Laboratory, scientists are using the Facility for Advanced Accelerator Experimental Tests, also known as FACET, to research accelerator science and high-energy density physics. SLAC's particle accelerator may be two miles long, but researchers at FACET are working to develop more compact versions that could be widely used in medicine and industry -- particle accelerators are used for cancer research, processing computer chips, and even producing the shrink wrap used to keep your Thanksgiving turkey fresh. In this photo, Stanford graduate student Spencer Gessner assembles a camera that will monitor an X-ray spectrometer designed to measure FACET's beam energy. Learn more about how FACET works. | Photo courtesy of SLAC National Accelerator Laboratory.

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

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

SciTech Connect

The twenty-second Particle Accelerator Conference, PAC'07, took place at the Albuquerque Convention Centre in Albuquerque, the largest city in New Mexico, from Monday to Friday, 2007 June 25 to 29. It was attended by over 1350 delegates from 25 different countries (63% North America, 24% Europe, 11% Asia and 2% Other), and was held under the auspices of the two professional societies that oversee and make holding this series of conferences possible, the Division of Physics of Beams within APS, and the Nuclear and Plasma Sciences Society within IEEE. As host of the conference, Los Alamos National Laboratory (LANL) is especially thanked for their many contributions and assistance both prior to and during the conference. The Convention Center was an ideal location for information sharing and discussions between the interdisciplinary aspects of the accelerator community, as well as for related meetings and ad-hoc 'rump' sessions.

N /A

2007-08-01T23:59:59.000Z

122

New modes of particle accelerations techniques and sources. Formal report  

SciTech Connect

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

Parsa, Z. [ed.

1996-12-31T23:59:59.000Z

123

Energy Spectrum of Particles Accelerated in Relativistic Collisionless Shocks  

Science Journals Connector (OSTI)

We analytically study diffusive particle acceleration in relativistic, collisionless shocks. We find a simple relation between the spectral index s and the anisotropy of the momentum distribution along the shock front. Based on this relation, we obtain s=(3?u-2?u?d2+?d3)/(?u-?d) for isotropic diffusion, where ?u (?d) is the upstream (downstream) fluid velocity normalized to the speed of light. This result is in agreement with previous numerical determinations of s for all (?u,?d), and yields s=38/9 in the ultrarelativistic limit. The spectrum-anisotropy connection is useful for testing numerical studies and constraining anisotropic diffusion results. It suggests that the spectrum is highly sensitive to the form of the diffusion function for particles traveling along the shock front.

Uri Keshet and Eli Waxman

2005-03-24T23:59:59.000Z

124

Particle acceleration and radiation by direct electric fields in flaring complex solar active regions  

E-Print Network (OSTI)

to connect the energy re- lease process with the acceleration of electrons in solar flares, using a CA modelParticle acceleration and radiation by direct electric fields in flaring complex solar active-Meudon, 92195 Meudon Cedex, FRANCE Abstract The acceleration and radiation of solar energetic particles

Anastasiadis, Anastasios

125

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

E-Print Network (OSTI)

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams C. B. Schroeder, E 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

Geddes, Cameron Guy Robinson

126

Randomly accelerated particle in a box: Mean absorption time for partially absorbing and inelastic boundaries  

E-Print Network (OSTI)

Randomly accelerated particle in a box: Mean absorption time for partially absorbing and inelastic which is randomly accelerated by Gaussian white noise on the line segment 0 x 1 and is absorbed as soon accelerated particle which moves on the half line x 0 with an absorbing boundary at x=0. The motion

127

EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

04: Linac Coherent Light Source II at Stanford Linear 04: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California Summary This EA evaluates the environmental impacts of the proposed construction of the Linac Coherent Light Source at SLAC National Accelerator Laboratory, Menlo Park, California. Public Comment Opportunities None available at this time. For more information, contact: Mr. Dave Osugi DOE SLAC Site Office 2575 Sand Hill Road, MS8A Menlo Park, CA 94025 Electronic mail: dave.osugi@sso.science.doe.gov Documents Available for Download March 7, 2012 EA-1904: Finding of No Significant Impact Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, CA

128

EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

4: Linac Coherent Light Source II at Stanford Linear 4: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California Summary This EA evaluates the environmental impacts of the proposed construction of the Linac Coherent Light Source at SLAC National Accelerator Laboratory, Menlo Park, California. Public Comment Opportunities None available at this time. For more information, contact: Mr. Dave Osugi DOE SLAC Site Office 2575 Sand Hill Road, MS8A Menlo Park, CA 94025 Electronic mail: dave.osugi@sso.science.doe.gov Documents Available for Download March 7, 2012 EA-1904: Finding of No Significant Impact Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, CA

129

DOE - Office of Legacy Management -- Yale Heavy Ion Linear Accelerator - CT  

NLE Websites -- All DOE Office Websites (Extended Search)

Yale Heavy Ion Linear Accelerator - Yale Heavy Ion Linear Accelerator - CT 05 FUSRAP Considered Sites Site: Yale Heavy Ion Linear Accelerator (CT.05) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: New Haven , Connecticut CT.05-1 Evaluation Year: 1987 CT.05-3 Site Operations: Research and development with solvents. CT.05-1 Site Disposition: Eliminated - Potential for contamination remote based on limited amount of materials handled CT.05-3 Radioactive Materials Handled: Yes Primary Radioactive Materials Handled: Uranium, Radium CT.05-1 Radiological Survey(s): No Site Status: Eliminated from consideration under FUSRAP Also see Documents Related to Yale Heavy Ion Linear Accelerator CT.05-1 - MED Memorandum; To the Files, Thru Ruhoff, et. al.;

130

Particle Tracking in Circular Accelerators Using the Exact Hamiltonian in SixTrack  

E-Print Network (OSTI)

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

Fjellstrom, Mattias; Hansson, Johan

2013-12-13T23:59:59.000Z

131

An Efficient Fokker-Planck Solver and its Application to Stochastic Particle Acceleration in Galaxy Clusters  

E-Print Network (OSTI)

Particle acceleration by turbulence plays a role in many astrophysical environments. The non- linear evolution of the underlying cosmic-ray spectrum is complex and can be described by a Fokker-Planck equation, which in general has to be solved numerically. We present here an implementation to compute the evolution of a cosmic-ray spectrum coupled to turbulence considering isotropic particle pitch-angle distributions and taking into account the relevant particle energy gains and losses. Our code can be used in run time and post-processing to very large astrophysical fluid simulations. We also propose a novel method to compress cosmic- ray spectra by a factor of ten, to ease the memory demand in very large simulations. We show a number of code tests, which firmly establish the correctness of the code. In this paper we focus on relativistic electrons, but our code and methods can be easily extended to the case of hadrons. We apply our pipeline to the relevant problem of particle acceleration in galaxy clusters. ...

Donnert, Julius

2014-01-01T23:59:59.000Z

132

Proceedings of the Oak Ridge Electron Linear Accelerator (ORELA) Workshop  

SciTech Connect

The Oak Ridge National Laboratory (ORNL) organized a workshop at ORNL July 14-15, 2005, to highlight the unique measurement capabilities of the Oak Ridge Electron Linear Accelerator (ORELA) facility and to emphasize the important role of ORELA for performing differential cross-section measurements in the low-energy resonance region that is important for nuclear applications such as nuclear criticality safety, nuclear reactor and fuel cycle analysis, stockpile stewardship, weapons research, medical diagnosis, and nuclear astrophysics. The ORELA workshop (hereafter referred to as the Workshop) provided the opportunity to exchange ideas and information pertaining to nuclear cross-section measurements and their importance for nuclear applications from a variety of perspectives throughout the U.S. Department of Energy (DOE). Approximately 50 people, representing DOE, universities, and seven U.S. national laboratories, attended the Workshop. The objective of the Workshop was to emphasize the technical community endorsement for ORELA in meeting nuclear data challenges in the years to come. The Workshop further emphasized the need for a better understanding of the gaps in basic differential nuclear measurements and identified the efforts needed to return ORELA to a reliable functional measurement facility. To accomplish the Workshop objective, nuclear data experts from national laboratories and universities were invited to provide talks emphasizing the unique and vital role of the ORELA facility for addressing nuclear data needs. ORELA is operated on a full cost-recovery basis with no single sponsor providing complete base funding for the facility. Consequently, different programmatic sponsors benefit by receiving accurate cross-section data measurements at a reduced cost to their respective programs; however, leveraging support for a complex facility such as ORELA has a distinct disadvantage in that the programmatic funds are only used to support program-specific measurements. As a result, ORELA has not received base funding to support major upgrades and significant maintenance operations that are essential to keep the facility in a state of readiness over the long term. As a result, ORELA has operated on a ''sub-bare-minimum'' budget for the past 10 to 15 years, and the facility has not been maintained at a level for continued reliable operation for the long term. During the Workshop, Jerry McKamy (NNSA/NA-117) used a hospital patient metaphor that accurately depicts the facility status. ORELA is currently in the intensive care unit (ICU) on life support, and refurbishment efforts are needed to get the ''patient'' off life support and out to an ordinary hospital room. McKamy further noted that the DOE NCSP is planning to fund immediate refurbishment tasks ($1.5 M over three years) to help reestablish reliable ORELA operation (i.e., move ORELA from ICU to an ordinary hospital room). Furthermore, the NCSP will work to identify and carry out the actions needed to discharge ORELA from the ''hospital'' over the next five to seven years. In accordance with the Workshop objectives, the technical community publicly endorsed the need for a reliable ORELA facility that can meet current and future nuclear data needs. These Workshop proceedings provide the formal documentation of the technical community endorsement for ORELA. Furthermore, the proceedings highlight the past and current contributions that ORELA has made to the nuclear industry. The Workshop further emphasized the operational and funding problems that currently plague the facility, thereby limiting ORELA's operational reliability. Despite the recent operational problems, ORELA is a uniquely capable measurement facility that must be part of the overall U.S. nuclear data measurement portfolio in order to support current and emerging nuclear applications. The Workshop proceedings further emphasize that ORNL, the technical community, and programmatic sponsors are eager to see ORELA reestablish reliable measurement operation and be readily available to address nuclear data challe

Dunn, M.E.

2006-02-27T23:59:59.000Z

133

INTRA BEAM SCATTERING IN LINEAR ACCELERATORS, ESPECIALLY ERLS  

E-Print Network (OSTI)

radiation protection system. INTRODUCTION Single event intra-beam scattering (IBS) that leads to momentum complete propagation of scattered particle. For the example of the ERL x-ray facility that Cornell plans the current of lost particles can pose a radiation hazard. In this paper we describe tracking simulations

134

Radiation from a uniformly accelerated particle detector: Energy, particles, and the quantum measurement process  

Science Journals Connector (OSTI)

We comment on the controversy whether a uniformly accelerated particle detector radiates. We stress the particular importance of the built-up correlations and of the quantum measurement process in this connection. We give the question the following form: We assume that the initial state of the quantum field is the Minkowski vacuum and that there is a uniformly accelerated two-level system which is initially in its ground state. What will in this case be found in the different regions of asymptotic future null infinity for the mean value of the field energy density on one hand and of the Minkowski particle number on the other if in the out region (a) no measurement is made on the two-level system, (b) the measurement finds the two-level system in its upper state, or (c) in its lower state? To obtain localized statements, we base the calculations on wave packet states. The different cases show essential differences.

Jürgen Audretsch and Rainer Müller

1994-06-15T23:59:59.000Z

135

SINGLE CRYSTAL NIOBIUM TUBES FOR PARTICLE COLLIDERS ACCELERATOR CAVITIES  

SciTech Connect

The objective of this research project is to produce single crystal niobium (Nb) tubes for use as particle accelerator cavities for the Fermi laboratory’s International Linear Collider project. Single crystal Nb tubes may have superior performance compared to a polycrystalline tubes because the absence of grain boundaries may permit the use of higher accelerating voltages. In addition, Nb tubes that are subjected to the high temperature, high vacuum crystallization process are very pure and well annealed. Any impurity with a significantly higher vapor pressure than Nb should be decreased by the relatively long exposure at high temperature to the high vacuum environment. After application of the single crystal process, the surfaces of the Nb tubes are bright and shiny, and the tube resembles an electro polished Nb tube. For these reasons, there is interest in single crystal Nb tubes and in a process that will produce single crystal tubes. To convert a polycrystalline niobium tube into a single crystal, the tube is heated to within a few hundred ?C of the melting temperature of niobium, which is 2477 ?C. RF heating is used to rapidly heat the tube in a narrow zone and after reaching the operating temperature, the hot zone is slowly passed along the length of the tube. For crystallization tests with Nb tubes, the traverse rate was in the range of 1-10 cm per hour. All the crystallization tests in this study were performed in a water-cooled, stainless steel chamber under a vacuum of 5 x10-6 torr or better. In earliest tests of the single crystal growth process, the Nb tubes had an OD of 1.9 cm and a wall thickness of 0.15 mm. With these relatively small Nb tubes, the single crystal process was always successful in producing single crystal tubes. In these early tests, the operating temperature was normally maintained at 2200 ?C, and the traverse rate was 5 cm per hour. In the next test series, the Nb tube size was increased to 3.8 cm OD and the wall thickness was increased 0.18 mm and eventually to 0.21 mm. Again, with these larger tubes, single crystal tubes were usually produced by the crystallization process. The power supply was generally operated at full output during these tests, and the traverse rate was 5 cm per hour. In a few tests, the traverse rate was increased to 10 cm per hour, and at the faster traverse rate, single crystal growth was not achieved. In these tests with a faster traverse rate, it was thought that the tube was not heated to a high enough temperature to achieve single crystal growth. In the next series of tests, the tube OD was unchanged at 3.8 cm and the wall thickness was increased to 0.30 mm. The increased wall thickness made it difficult to reach an operating temperature above 2,000 ?C, and although the single crystal process caused a large increase in the crystal grains, no single crystal tubes were produced. It was assumed that the operating temperature in these tests was not high enough to achieve single crystal growth. In FY 2012, a larger power supply was purchased and installed. With the new power supply, temperatures above the melting point of Nb were easily obtained regardless of the tube thickness. A series of crystallization tests was initiated to determine if indeed the operating temperature of the previous tests was too low to achieve single crystal growth. For these tests, the Nb tube OD remained at 3.8 cm and the wall thickness was 0.30 mm. The first test had an operating temperature of 2,000 ?C. and the operating temperature was increased by 50 ?C increments for each successive test. The final test was very near the Nb melting temperature, and indeed, the Nb tube eventually melted in the center of the tube. These tests showed that higher temperatures did yield larger grain sizes if the traverse rate was held constant at 5 cm per hour, but no single crystal tubes were produced even at the highest operating temperature. In addition, slowing the traverse rate to as low as 1 cm per hour did not yield a single crystal tube regardless of operating temperature. At this time, it

MURPHY, JAMES E [University of Nevada, Reno] [University of Nevada, Reno

2013-02-28T23:59:59.000Z

136

Relativistic electrodynamics Lagrangian and Hamiltonian for particle accelerators  

Science Journals Connector (OSTI)

A Lagrangian L of a dynamical system is a function that summarises the dynamics of the system (Goldstein et al., 2002). If the Lagrangian of a system is known, then the equations of motion of the system may be obtained by its direct substitution into the Euler-Lagrange equation. One important advantage of the Lagrange formulation of dynamical systems is that the formulation is not tied to any particular coordinate system – rather, any convenient set of variables may be used to describe the system. Finding the Lagrangian for a system is a mix of science and art. In the following paper we will demonstrate how to find it for the case of relativistic electrodynamics as a direct application for particle accelerators. We will show how we can start from the expression of the Lagrangian in classical electrodynamics in finding its expression for relativistic cases.

Adrian Sfarti

2010-01-01T23:59:59.000Z

137

2011 PARTICLE ACCELERATOR CONFERENCE TOUR REGISTRATION FORM (Tour tickets will be held under this name)  

E-Print Network (OSTI)

2011 PARTICLE ACCELERATOR CONFERENCE ­ TOUR REGISTRATION FORM Name or electrical difficulties; strikes, lockouts, acts or threats of terrorism; civil disorder, acts of God

138

E-Print Network 3.0 - accelerated charged particles Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

"Space charge debunching and compensation in a laser particle acceleration system... Optronics, 2755 Northup Way, Bellevue, WA 98004-1495 Abstract. Laser ... Source: Brookhaven...

139

Diagnostic resonant cavity for a charged particle accelerator  

DOE Patents (OSTI)

Disclosed is a diagnostic resonant cavity for determining characteristics of a charged particle beam, such as an electron beam, produced in a charged particle accelerator. The cavity is based on resonant quadrupole-mode and higher order cavities. Enhanced shunt impedance in such cavities is obtained by the incorporation of a set of four or more electrically conductive rods extending inwardly from either one or both of the end walls of the cavity, so as to form capacitive gaps near the outer radius of the beam tube. For typical diagnostic cavity applications, a five-fold increase in shunt impedance can be obtained. In alternative embodiments the cavity may include either four or more opposing pairs of rods which extend coaxially toward one another from the opposite end walls of the cavity and are spaced from one another to form capacitative gaps; or the cavity may include a single set of individual rods that extend from one end wall to a point adjacent the opposing end wall.

Barov, Nikolai (San Diego, CA)

2007-10-02T23:59:59.000Z

140

Generalized linear Boltzmann equations for particle transport in polycrystals  

E-Print Network (OSTI)

The linear Boltzmann equation describes the macroscopic transport of a gas of non-interacting point particles in low-density matter. It has wide-ranging applications, including neutron transport, radiative transfer, semiconductors and ocean wave scattering. Recent research shows that the equation fails in highly-correlated media, where the distribution of free path lengths is non-exponential. We investigate this phenomenon in the case of polycrystals whose typical grain size is comparable to the mean free path length. Our principal result is a new generalized linear Boltzmann equation that captures the long-range memory effects in this setting. A key feature is that the distribution of free path lengths has an exponential decay rate, as opposed to a power-law distribution observed in a single crystal.

Jens Marklof; Andreas Strömbergsson

2015-02-13T23:59:59.000Z

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141

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers  

DOE Patents (OSTI)

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Danby, Gordon T. (Wading River, NY); Jackson, John W. (Shoreham, NY)

1991-01-01T23:59:59.000Z

142

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers  

DOE Patents (OSTI)

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

Danby, G.T.; Jackson, J.W.

1990-03-19T23:59:59.000Z

143

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

SciTech Connect

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

P.F. Schmit and N.J. Fisch

2009-06-17T23:59:59.000Z

144

Advance in Vertical Buffered Electropolishing on Niobium for Particle Accelerators*  

SciTech Connect

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

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

2011-09-01T23:59:59.000Z

145

PARTICLE ACCELERATION AT QUASI-PARALLEL SHOCK WAVES: THEORY AND OBSERVATIONS AT 1 AU  

SciTech Connect

In this paper, we describe a theoretical model for accelerating an arbitrary upstream particle distribution. Only those particles that exceed a prescribed injection energy, E{sub inj}, are accelerated via the diffusive shock acceleration (DSA) mechanism, also known as first-order Fermi acceleration. We identify a set of quasi-parallel shocks at 1 AU and use the observed solar wind particle distribution information to construct our upstream distribution, which is then accelerated diffusively at the shock, assuming the observed shock parameters. The injection energy for particles to be accelerated diffusively at a quasi-parallel shock is discussed theoretically. By using the observed upstream solar wind distribution function and the observed shock parameters, we can compute the injection energy that matches the observed downstream accelerated particle spectrum. Like the previous studies of van Nes et al., Lario et al., and Ho et al., this analysis focuses on the acceleration of protons only via the first-order Fermi acceleration mechanism. However, our primary focus is on quasi-parallel shocks and the injection mechanism in the context of DSA with a background thermal solar wind modeled as a Maxwellian or kappa distribution. Our approach allows for a direct test of injection at interplanetary shocks. It has been proposed that an additional seed population of energetic particles is needed to explain the accelerated particle distribution downstream of quasi-parallel shocks. This conclusion is based typically on studies that address the acceleration of heavy ions primarily and do not characterize the injection of protons alone using the DSA mechanism. Through comparisons of Maxwellian and kappa upstream distributions, we find that DSA with injection directly from a thermal Maxwellian distribution, or weak departures therefrom, for protons is responsible for energetic solar particle events associated with quasi-parallel shocks.

Neergaard Parker, L.; Zank, G. P., E-mail: lnp0012@uah.edu [Physics Department, Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

2012-09-20T23:59:59.000Z

146

A FLUX ROPE NETWORK AND PARTICLE ACCELERATION IN THREE-DIMENSIONAL RELATIVISTIC MAGNETIC RECONNECTION  

SciTech Connect

We investigate magnetic reconnection and particle acceleration in relativistic pair plasmas with three-dimensional particle-in-cell simulations of a kinetic-scale current sheet in a periodic geometry. We include a guide field that introduces an inclination between the reconnecting field lines and explore outside-of-the-current sheet magnetizations that are significantly below those considered by other authors carrying out similar calculations. Thus, our simulations probe the transitional regime in which the magnetic and plasma pressures are of the same order of magnitude. The tearing instability is the dominant mode in the current sheet for all guide field strengths, while the linear kink mode is less important even without the guide field, except in the lower magnetization case. Oblique modes seem to be suppressed entirely. In its nonlinear evolution, the reconnection layer develops a network of interconnected and interacting magnetic flux ropes. As smaller flux ropes merge into larger ones, the reconnection layer evolves toward a three-dimensional, disordered state in which the resulting flux rope segments contain magnetic substructure on plasma skin depth scales. Embedded in the flux ropes, we detect spatially and temporally intermittent sites of dissipation reflected in peaks in the parallel electric field. Magnetic dissipation and particle acceleration persist until the end of the simulations, with simulations with higher magnetization and lower guide field strength exhibiting greater and faster energy conversion and particle energization. At the end of our largest simulation, the particle energy spectrum attains a tail extending to high Lorentz factors that is best modeled with a combination of two additional thermal components. We confirm that the primary energization mechanism is acceleration by the electric field in the X-line region. The highest-energy positrons (electrons) are moderately beamed with median angles {approx}30 Degree-Sign -40 Degree-Sign relative to (the opposite of) the direction of the initial current density, but we speculate that reconnection in more highly magnetized plasmas would give rise to stronger beaming. Finally, we discuss the implications of our results for macroscopic reconnection sites, and which of our results may be expected to hold in systems with higher magnetizations.

Kagan, Daniel; Milosavljevic, Milos [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Spitkovsky, Anatoly [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-09-01T23:59:59.000Z

147

MODELING FOCUSED ACCELERATION OF COSMIC-RAY PARTICLES BY STOCHASTIC METHODS  

SciTech Connect

Schlickeiser and Shalchi suggested that a first-order Fermi mechanism of focused particle acceleration could be important in several astrophysical applications. In order to investigate focused acceleration, we express the Fokker-Planck equation as an equivalent system of stochastic differential equations. We simplify the system for a set of physically motivated parameters, extend the analytical theory, and determine the evolving particle distribution numerically. While our numerical results agree with the focused acceleration rate of Schlickeiser and Shalchi for a weakly anisotropic particle distribution, we establish significant limitations of the analytical approach. Momentum diffusion is found to be more significant than focused acceleration at early times. Most critically, the particle distribution rapidly becomes anisotropic, leading to a much slower momentum gain rate. We discuss the consequences of our results for the role of focused acceleration in astrophysics.

Armstrong, C. K.; Litvinenko, Yuri E.; Craig, I. J. D., E-mail: cka3@waikato.ac.nz, E-mail: yuril@waikato.ac.nz, E-mail: i.craig@waikato.ac.nz [Department of Mathematics, University of Waikato, P. B. 3105, Hamilton (New Zealand)

2012-10-01T23:59:59.000Z

148

Effect of polarization and focusing on laser pulse driven auto-resonant particle acceleration  

SciTech Connect

The effect of laser polarization and focusing is theoretically studied on the final energy gain of a particle in the Auto-resonant acceleration scheme using a finite duration laser pulse with Gaussian shaped temporal envelope. The exact expressions for dynamical variables viz. position, momentum, and energy are obtained by analytically solving the relativistic equation of motion describing particle dynamics in the combined field of an elliptically polarized finite duration pulse and homogeneous static axial magnetic field. From the solutions, it is shown that for a given set of laser parameters viz. intensity and pulse length along with static magnetic field, the energy gain by a positively charged particle is maximum for a right circularly polarized laser pulse. Further, a new scheme is proposed for particle acceleration by subjecting it to the combined field of a focused finite duration laser pulse and static axial magnetic field. In this scheme, the particle is initially accelerated by the focused laser field, which drives the non-resonant particle to second stage of acceleration by cyclotron Auto-resonance. The new scheme is found to be efficient over two individual schemes, i.e., auto-resonant acceleration and direct acceleration by focused laser field, as significant particle acceleration can be achieved at one order lesser values of static axial magnetic field and laser intensity.

Sagar, Vikram; Sengupta, Sudip; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)

2014-04-15T23:59:59.000Z

149

MSci Project 2014-2015 Dr Brian Reville Particle Acceleration at Astrophysical Shocks  

E-Print Network (OSTI)

-rays. They form the most remarkable particle distribution in the Universe, having an almost featureless non-thermal atmosphere is continuously bombarded by energetic particles, protons, electrons etc known as cosmic to the theory of diffusive shock acceleration of energetic particles in tenuous plasma, Reports on Prog.Phys. 46

Paxton, Anthony T.

150

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)

2010-07-15T23:59:59.000Z

151

A Lagrangian particle method for the simulation of linear and nonlinear elastic models of soft tissue  

Science Journals Connector (OSTI)

We present a novel Lagrangian particle method for the simulation of linear and nonlinear elastic models of soft tissue. Linear solids are represented by the Lagrangian formulation of the stress-strain relationship that is extended to nonlinear solids ... Keywords: Lagrangian particle methods, Linear and nonlinear elasticity, Liver tissue simulation

Simone E. Hieber; Petros Koumoutsakos

2008-11-01T23:59:59.000Z

152

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

SciTech Connect

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

Byer, Robert L.

2013-11-07T23:59:59.000Z

153

#LabChat: Particle Accelerators, Lasers and Discovery Science, May 17 at  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Particle Accelerators, Lasers and Discovery Science, May Particle Accelerators, Lasers and Discovery Science, May 17 at 1pm EST #LabChat: Particle Accelerators, Lasers and Discovery Science, May 17 at 1pm EST May 15, 2012 - 2:03pm Addthis SLAC’s linac accelerates very short pulses of electrons to 99.9999999 percent the speed of light through a slalom that causes the electrons to emit X-rays, which become synchronized as they interact with the electron pulses and create the world’s brightest X-ray laser pulse. | Photo by Brad Plummer, SLAC. SLAC's linac accelerates very short pulses of electrons to 99.9999999 percent the speed of light through a slalom that causes the electrons to emit X-rays, which become synchronized as they interact with the electron pulses and create the world's brightest X-ray laser pulse. | Photo by

154

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

SciTech Connect

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

Lawrence, G. [comp.

1997-07-01T23:59:59.000Z

155

A Phenomenological Cost Model for High Energy Particle Accelerators  

E-Print Network (OSTI)

Accelerator-based high-energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the colliders has progressed immensely, while the beam energy, luminosity, facility size, and cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. In this paper we derive a simple scaling model for the cost of large accelerators and colliding beam facilities based on costs of 17 big facilities which have been either built or carefully estimated. Although this approach cannot replace an actual cost estimate based on an engineering design, this parameterization is to indicate a somewhat realistic cost range for consideration of what future frontier accelerator facilities might be fiscally realizable.

Vladimir Shiltsev

2014-04-15T23:59:59.000Z

156

U.S. Completes Contribution to World's Most Powerful Particle Accelerator |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Completes Contribution to World's Most Powerful Particle Completes Contribution to World's Most Powerful Particle Accelerator U.S. Completes Contribution to World's Most Powerful Particle Accelerator June 30, 2008 - 2:15pm Addthis WASHINGTON, DC - The U.S. contribution to the Large Hadron Collider (LHC) has been completed on budget and ahead of schedule, the U.S. Department of Energy (DOE) and the National Science Foundation (NSF) said today. The LHC, located near Geneva, Switzerland at the CERN laboratory, is the largest international scientific facility ever built. The U.S. contribution, a $531 million investment, consists of several key components of the particle accelerator and the ATLAS and CMS particle detectors. "The success of the U.S. LHC project is based on the quality of the U.S. teams, and national and international collaboration," DOE Under Secretary

157

High-Energy Behaviour of the Particle Spectrum Created by a Linearly Expanding Universe  

Science Journals Connector (OSTI)

......research-article Articles High-Energy Behaviour of the Particle Spectrum...Cuidad Universitaria, Buenos Aires. Argentina. It is proved that the number and energy densities of the high-energy particles created by a linearly expanding......

Mario Castagnino

1981-12-01T23:59:59.000Z

158

Diffusive Particle Acceleration in Shocked, Viscous Accretion Disks: Green's Function Energy Distribution  

Science Journals Connector (OSTI)

The acceleration of relativistic particles in a viscous accretion disk containing a standing shock is investigated as a possible explanation for the energetic outflows observed around radio-loud black holes. The energy/space distribution of the accelerated particles is computed by solving a transport equation that includes the effects of first-order Fermi acceleration, bulk advection, spatial diffusion, and particle escape. The velocity profile of the accreting gas is described using a model for shocked viscous disks recently developed by the authors, and the corresponding Green's function distribution for the accelerated particles in the disk and the outflow is obtained using a classical method based on eigenfunction analysis. The accretion-driven, diffusive shock acceleration scenario explored here is conceptually similar to the standard model for the acceleration of cosmic rays at supernova-driven shocks. However, in the disk application, the distribution of the accelerated particles is much harder than would be expected for a plane-parallel shock with the same compression ratio. Hence the disk environment plays a key role in enhancing the efficiency of the shock acceleration process. The presence of the shock helps to stabilize the disk by reducing the Bernoulli parameter, while channeling the excess binding energy into the escaping relativistic particles. In applications to M87 and Sgr A*, we find that the kinetic power in the jet is , and the outflowing relativistic particles have a mean energy ~300 times larger than that of the thermal gas in the disk at the shock radius. Our results suggest that a standing shock may be an essential ingredient in accretion onto underfed black holes, helping to resolve the long-standing problem of the stability of advection-dominated accretion disks.

Peter A. Becker; Santabrata Das; Truong Le

2011-01-01T23:59:59.000Z

159

Quasi-linear heating and acceleration in bi-Maxwellian plasmas  

SciTech Connect

Quasi-linear acceleration and heating rates are derived for drifting bi-Maxwellian distribution functions in a general nonrelativistic case for arbitrary wave vectors, propagation angles, and growth/damping rates. The heating rates in a proton-electron plasma due to ion-cyclotron/kinetic Alfvén and mirror waves for a wide range of wavelengths, directions of propagation, and growth or damping rates are explicitly computed.

Hellinger, Petr [Astronomical Institute and Institute of Atmospheric Physics, AS CR Bocni II/1401, CZ-14131 Prague (Czech Republic)] [Astronomical Institute and Institute of Atmospheric Physics, AS CR Bocni II/1401, CZ-14131 Prague (Czech Republic); Passot, Thierry; Sulem, Pierre-Louis [Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4 (France)] [Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4 (France); Trávní?ek, Pavel M. [Astronomical Institute and Institute of Atmospheric Physics, AS CR Bocni II/1401, CZ-14131 Prague (Czech Republic) [Astronomical Institute and Institute of Atmospheric Physics, AS CR Bocni II/1401, CZ-14131 Prague (Czech Republic); Space Sciences Laboratory, University of Berkeley, 7 Gauss Way, Berkeley, California 94720 (United States)

2013-12-15T23:59:59.000Z

160

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle Cormier-Michel,1,2  

E-Print Network (OSTI)

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle of laser wakefield accelerators using particle-in-cell codes are investigated. A dark current free laser wakefield accelerator stage, in which no trapping of background plasma electrons into the plasma wave should

Geddes, Cameron Guy Robinson

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Acceleration and storage of energetic particles in the solar corona  

Science Journals Connector (OSTI)

Observations of solar energetic particles (SEP) in interplanetary space ... of coronal diffusion. Finally, new results of solar flare gamma-ray emission at high energies ... are discussed which shed new light on ...

K. -P. Wenzel

1994-01-01T23:59:59.000Z

162

Accelerator Physics Accelerators form the backbone of SLAC's on-site experimental program. Research at SLAC  

E-Print Network (OSTI)

#12;Accelerator Physics Accelerators form the backbone of SLAC's on-site experimental program. Research at SLAC is continually improving accelerators, both here and at other laboratories, and paving the way for a new generation of particle acceleration technology. SLAC's famous linear accelerator

Wechsler, Risa H.

163

Possible thermodynamic law violations and astrophysical issues for secular acceleration of electrodynamic particles in the vacuum  

Science Journals Connector (OSTI)

A potentially significant consequence of the dynamics due to particles interacting electromagnetically with electromagnetic zero-point plus Planckian radiation is the prediction of a stochastic acceleration mechanism. For particles without constraining forces or other collision mechanisms present, such as due to the walls of a container or to interparticle collisions, this mechanism results in average speeds that continue to increase with time. This secular acceleration effect has been proposed and analyzed in the past by Rueda and others [A. Rueda, Space Sci. Rev. 53, 223 (1990)]for being a possible source for cosmic-ray production; other possible astrophysical consequences have also been examined. However, the thermodynamics of secular acceleration have presented conceptual problems, such as the apparent source of continual average energy extraction and the possible violation of the second law of thermodynamics. These concerns are examined in detail here, with the conclusion that secular acceleration does not appear to violate these basic laws.

Daniel C. Cole

1995-03-01T23:59:59.000Z

164

Assessing Risk in Costing High-energy Accelerators: from Existing Projects to the Future Linear Collider  

E-Print Network (OSTI)

High-energy accelerators are large projects funded by public money, developed over the years and constructed via major industrial contracts both in advanced technology and in more conventional domains such as civil engineering and infrastructure, for which they often constitute one-of markets. Assessing their cost, as well as the risk and uncertainty associated with this assessment is therefore an essential part of project preparation and a justified requirement by the funding agencies. Stemming from the experience with large circular colliders at CERN, LEP and LHC, as well as with the Main Injector, the Tevatron Collider Experiments and Accelerator Upgrades, and the NOvA Experiment at Fermilab, we discuss sources of cost variance and derive cost risk assessment methods applicable to the future linear collider, through its two technical approaches for ILC and CLIC. We also address disparities in cost risk assessment imposed by regional differences in regulations, procedures and practices.

Lebrun, Philippe

2010-01-01T23:59:59.000Z

165

New applications of particle accelerators in medicine, materials science, and industry  

SciTech Connect

Recently, the application of particle accelerators to medicine, materials science, and other industrial uses has increased dramatically. A random sampling of some of these new programs is discussed, primarily to give the scope of these new applications. The three areas, medicine, materials science or solid-state physics, and industrial applications, are chosen for their diversity and are representative of new accelerator applications for the future.

Knapp, E.A.

1981-01-01T23:59:59.000Z

166

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

E-Print Network (OSTI)

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

A. J. S. Hamilton

2013-05-20T23:59:59.000Z

167

MONTE CARLO SIMULATIONS OF NONLINEAR PARTICLE ACCELERATION IN PARALLEL TRANS-RELATIVISTIC SHOCKS  

SciTech Connect

We present results from a Monte Carlo simulation of a parallel collisionless shock undergoing particle acceleration. Our simulation, which contains parameterized scattering and a particular thermal leakage injection model, calculates the feedback between accelerated particles ahead of the shock, which influence the shock precursor and 'smooth' the shock, and thermal particle injection. We show that there is a transition between nonrelativistic shocks, where the acceleration efficiency can be extremely high and the nonlinear compression ratio can be substantially greater than the Rankine-Hugoniot value, and fully relativistic shocks, where diffusive shock acceleration is less efficient and the compression ratio remains at the Rankine-Hugoniot value. This transition occurs in the trans-relativistic regime and, for the particular parameters we use, occurs around a shock Lorentz factor ?{sub 0} = 1.5. We also find that nonlinear shock smoothing dramatically reduces the acceleration efficiency presumed to occur with large-angle scattering in ultra-relativistic shocks. Our ability to seamlessly treat the transition from ultra-relativistic to trans-relativistic to nonrelativistic shocks may be important for evolving relativistic systems, such as gamma-ray bursts and Type Ibc supernovae. We expect a substantial evolution of shock accelerated spectra during this transition from soft early on to much harder when the blast-wave shock becomes nonrelativistic.

Ellison, Donald C.; Warren, Donald C. [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States); Bykov, Andrei M., E-mail: don_ellison@ncsu.edu, E-mail: ambykov@yahoo.com [Ioffe Institute for Physics and Technology, 194021 St. Petersburg (Russian Federation)

2013-10-10T23:59:59.000Z

168

The acceleration of electrons at perpendicular shocks and its implication for solar energetic particle events  

SciTech Connect

We present a study of the acceleration of electrons at a perpendicular shock that propagates through a turbulent magnetic field. The energization process of electrons is investigated by utilizing a combination of hybrid (kinetic ions and fluid electron) simulations and test-particle electron simulations. In this method, the motions of the test-particle electrons are numerically integrated in the time-dependent electric and magnetic fields generated by two-dimensional hybrid simulations. We show that large-scale magnetic fluctuations effect electrons in a number of ways and lead to efficient and rapid energization at the shock front. Since the electrons mainly follow along magnetic lines of force, the large-scale braiding of field lines in space allows the fast-moving electrons to interact with the shock front and get accelerated multiple times. Ripples in the shock front occurring at various scales will also contribute to the acceleration by mirroring the electrons. Our calculation shows that this process favors electron acceleration at perpendicular shocks. The acceleration efficiency is critically dependent on the turbulence amplitude and coherence length. We also discuss the implication of this study for solar energetic particles (SEPs) by comparing the acceleration of electrons with that of protons. Their correlation indicates that perpendicular shocks play an important role in SEP events.

Guo Fan; Giacalone, Joe [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States)

2012-11-20T23:59:59.000Z

169

On a theory of two-beam mechanisms of charged particle acceleration in electrodynamic structures  

SciTech Connect

This work is devoted to the theoretical studies of two-beam mechanisms of charged particle acceleration in electronic structures. The first section continues the outline of results of theoretical studies commenced in the intermediate report and considers the two-beam scheme of acceleration in the plasma waveguide. According to this scheme the strong current relativistic electron beam (REB) excites the intensive plasma waves accelerating the electrons of the second beam. The driving beam is assumed to be density-modulated. The preliminary modulation of the driving REB is shown to enhance substantially the acceleration efficiency of relativistic electrons of the driven beam. The second section deals with the two-beam acceleration in the vacuum corrugated waveguide. According to this scheme the excitation of electromagnetic waves and acceleration of driven beam electrons by them is accomplished under different Cherenkov resonances between the particles of beams and the corrugated waveguide field. The electromagnetic field in the periodic structure is known to be the superposition of spatial harmonics. With the small depth of the periodic nonuniformity the amplitudes of these harmonics decrease fast with their number increasing. Therefore, if the driving beam is in the Cherenkov resonance with the first spatial harmonic and the driven beam is in resonance with the zero space harmonic then the force accelerating the driven beam would be considerably bigger than the force decelerating the driving beam electrons.

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

1993-09-01T23:59:59.000Z

170

Particle acceleration by Majumdar-Papapetrou di-hole  

E-Print Network (OSTI)

We explore the multi-black hole spacetimes from the perspective of the ultra-high energy particle collisions. Such a discussion is limited to the spacetimes containing a single black hole so far. We deal with the Majumdar-Papapetrou solution representing a system consisting of two identical black holes in the equilibrium. In order to identify the conditions suitable for the process of high energy collisions, we consider particles confined to move on the equatorial plane towards the axis of symmetry with the zero angular momentum. We consider collision between the particles moving in opposite directions at the location midway between the black holes on the axis. We show that the center of mass energy of collision between the particles increases with the decrease in the separation between the black holes and shows divergence in the limit where the separation goes to zero. We estimate the size of the region close to the central point on the equatorial plane where it would be possible to have high energy collisions and show that this region has a reasonably large spatial extent. We further explore the process of high energy collisions with the general geodesics with arbitrary angular momentum on the equatorial plane away from the central point. Although in this paper we deal with theMajumdar-Papapetrou spacetime which serves as a toy example representing multiple black holes, we speculate on the possibility that the ultra-high energy collisions would also occur in the more general setting like colliding black holes, when distance between the black holes is extremely small, which can in principle be verified in the numerical relativity simulations.

Mandar Patil; Pankaj S. Joshi

2014-09-03T23:59:59.000Z

171

Stanford Linear Accelerator Center, Order R2-2005-0022, May 18, 2005  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD SAN FRANCISCO BAY REGION ORDER No. R2-2005-0022 RESCISSION of: ORDER No. 85-88, WASTE DISCHARGE REQUIREMENTS and ADOPTION of: SITE CLEANUP REQUIREMENTS for: STANFORD UNIVERSITY and the UNITED STATES DEPARTMENT OF ENERGY for the property located at the: STANFORD LINEAR ACCELERATOR CENTER 2575 SAND HILL ROAD MENLO PARK, SAN MATEO COUNTY FINDINGS: The California Regional Water Quality Control Board, San Francisco Bay Region (Water Board) finds that: 1. Purpose of Order This Order establishes Site Cleanup Requirements for the investigation and remediation of impacted soil and groundwater resulting from historical spills and leaks that have occurred during the course of operations of the Stanford Linear

172

A MODEL FOR THE ESCAPE OF SOLAR-FLARE-ACCELERATED PARTICLES  

SciTech Connect

We address the problem of how particles are accelerated by solar flares can escape into the heliosphere on timescales of an hour or less. Impulsive solar energetic particle (SEP) bursts are generally observed in association with so-called eruptive flares consisting of a coronal mass ejection (CME) and a flare. These fast SEPs are believed to be accelerated directly by the flare, rather than by the CME shock. However, the precise mechanism by which the particles are accelerated remains controversial. Regardless of the origin of the acceleration, the particles should remain trapped in the closed magnetic fields of the coronal flare loops and the ejected flux rope, given the magnetic geometry of the standard eruptive-flare model. In this case, the particles would reach the Earth only after a delay of many hours to a few days (coincident with the bulk ejecta arriving at Earth). We propose that the external magnetic reconnection intrinsic to the breakout model for CME initiation can naturally account for the prompt escape of flare-accelerated energetic particles onto open interplanetary magnetic flux tubes. We present detailed 2.5-dimensional magnetohydrodynamic simulations of a breakout CME/flare event with a background isothermal solar wind. Our calculations demonstrate that if the event occurs sufficiently near a coronal-hole boundary, interchange reconnection between open and closed fields can occur. This process allows particles from deep inside the ejected flux rope to access solar wind field lines soon after eruption. We compare these results to standard observations of impulsive SEPs and discuss the implications of the model on further observations and calculations.

Masson, S.; Antiochos, S. K. [Space Weather Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); DeVore, C. R., E-mail: sophie.masson@nasa.gov [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)

2013-07-10T23:59:59.000Z

173

Comparison of test particle acceleration in torsional spine and fan reconnection regimes  

SciTech Connect

Magnetic reconnection is a common phenomenon taking place in astrophysical and space plasmas, especially in solar flares which are rich sources of highly energetic particles. Torsional spine and fan reconnections are important mechanisms proposed for steady-state three-dimensional null-point reconnection. By using the magnetic and electric fields for these regimes, we numerically investigate the features of test particle acceleration in both regimes with input parameters for the solar corona. By comparison, torsional spine reconnection is found to be more efficient than torsional fan reconnection in an acceleration of a proton to a high kinetic energy. A proton can gain as high as 100?MeV of relativistic kinetic energy within only a few milliseconds. Moreover, in torsional spine reconnection, an accelerated particle can escape either along the spine axis or on the fan plane depending on its injection position. However, in torsional fan reconnection, the particle is only allowed to accelerate along the spine axis. In addition, in both regimes, the particle's trajectory and final kinetic energy depend on the injection position but adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory.

Hosseinpour, M., E-mail: hosseinpour@tabrizu.ac.ir; Mehdizade, M.; Mohammadi, M. A. [Plasma Physics Department, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2014-10-15T23:59:59.000Z

174

Noninterceptive method to measure longitudinal Twiss parameters of a beam in a hadron linear accelerator using beam position monitors  

A new method of measuring of the rms longitudinal Twiss parameters of a beam in linear accelerators is presented. It is based on using sum signals from beam position monitors sensitive to the longitudinal charge distribution in the bunch. The applicability of the method is demonstrated on the superconducting section of the Oak Ridge Spallation Neutron Source linear accelerator. The results are compared to a direct measurement of the bunch longitudinal profiles using an interceptive bunch shape monitor in the linac warm section of the same accelerator. Limitations of the method are discussed. The method is fast and simple, and can be used to obtain the initial parameters for the longitudinal matching in linear accelerators where interceptive diagnostics are not desirable.

Shishlo, A.; Aleksandrov, A.

2013-06-01T23:59:59.000Z

175

Extragalactic circuits, transmission lines, and CR particle acceleration  

E-Print Network (OSTI)

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

Kronberg, Philipp P

2014-01-01T23:59:59.000Z

176

Small scale energy release and the acceleration and transport of energetic particles  

E-Print Network (OSTI)

Small scale energy release and the acceleration and transport of energetic particles Hugh Hudson1, and of their radio emission mechanisms. The RHESSI3 results are the most distinctive in this time frame observatory) 4 Very Large Array (Socorro, New Mexico) 5 Nobeyama Radio Heliograph (Nobeyama, Japan) 6

Hudson, Hugh

177

Particle-Accelerator Constraints on Isotropic Modifications of the Speed of Light Michael A. Hohensee,1  

E-Print Network (OSTI)

Particle-Accelerator Constraints on Isotropic Modifications of the Speed of Light Michael A stability of 300 GeV photons at the Tevatron constrains deviations of the speed of light relative The speed of light, c, has played a crucial role in both the conception of special and general relativity

Walsworth, Ronald L.

178

Coherent States of Accelerated Relativistic Quantum Particles, Vacuum Radiation and the Spontaneous Breakdown of the Conformal SU(2,2) Symmetry  

E-Print Network (OSTI)

We give a quantum mechanical description of accelerated relativistic particles in the framework of Coherent States (CS) of the (3+1)-dimensional conformal group SU(2,2), with the role of accelerations played by special conformal transformations and with the role of (proper) time translations played by dilations. The accelerated ground state $\\tilde\\phi_0$ of first quantization is a CS of the conformal group. We compute the distribution function giving the occupation number of each energy level in $\\tilde\\phi_0$ and, with it, the partition function Z, mean energy E and entropy S, which resemble that of an "Einstein Solid". An effective temperature T can be assigned to this "accelerated ensemble" through the thermodynamic expression dE/dS, which leads to a (non linear) relation between acceleration and temperature different from Unruh's (linear) formula. Then we construct the corresponding conformal-SU(2,2)-invariant second quantized theory and its spontaneous breakdown when selecting Poincar\\'e-invariant degenerated \\theta-vacua (namely, coherent states of conformal zero modes). Special conformal transformations (accelerations) destabilize the Poincar\\'e vacuum and make it to radiate.

M. Calixto; E. Perez-Romero; V. Aldaya

2010-12-21T23:59:59.000Z

179

Neutron source, linear-accelerator fuel enricher and regenerator and associated methods  

DOE Patents (OSTI)

A device for producing fissile material inside of fabricated nuclear elements so that they can be used to produce power in nuclear power reactors. Fuel elements, for example, of a LWR are placed in pressure tubes in a vessel surrounding a liquid lead-bismuth flowing columnar target. A linear-accelerator proton beam enters the side of the vessel and impinges on the dispersed liquid lead-bismuth columns and produces neutrons which radiate through the surrounding pressure tube assembly or blanket containing the nuclear fuel elements. These neutrons are absorbed by the natural fertile uranium-238 elements and are transformed to fissile plutonium-239. The fertile fuel is thus enriched in fissile material to a concentration whereby they can be used in power reactors. After use in the power reactors, dispensed depleted fuel elements can be reinserted into the pressure tubes surrounding the target and the nuclear fuel regenerated for further burning in the power reactor.

Steinberg, Meyer (Huntington Station, NY); Powell, James R. (Shoreham, NY); Takahashi, Hiroshi (Setauket, NY); Grand, Pierre (Blue Point, NY); Kouts, Herbert (Brookhaven, NY)

1982-01-01T23:59:59.000Z

180

A 50-MeV mm-wave electron linear accelerator system for production of tunable short wavelength synchrotron radiation  

SciTech Connect

The Advanced Photon Source (APS) at Argonne in collaboration with the University of Illinois at Chicago and the University of Wisconsin at Madison is developing a new millimeter wavelength, 50-MeV electron linear accelerator system for production of coherent tunable wavelength synchrotron radiation. Modern micromachining techniques based on deep etch x-ray lithography, LIGA (Lithografie, Galvanoformung, Abformung), capable of producing high-aspect ratio structures are being considered for the fabrication of the accelerating components.

Nassiri, A.; Kustom, R.L.; Mills, F.E.; Kang, Y.W.; Matthews, P.J.; Grudzien, D.; Song, J.; Horan, D. [Argonne National Lab., IL (United States). Advanced Photon Source Accelerator Systems Div.; Feinerman, A.D.; Willke, T.L. [Argonne National Lab., IL (United States). Advanced Photon Source Accelerator Systems Div.]|[Univ. of Illinois, Chicago, IL (United States). Dept. of Electrical Engineering and Computer Science; Henke, H. [Argonne National Lab., IL (United States). Advanced Photon Source Accelerator Systems Div.]|[Technische Univ., Berlin (Germany). Inst. fuer Theoretische Electrotechnik

1993-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Particle acceleration at corotating interaction regions in the three-dimensional heliosphere  

SciTech Connect

We have investigated the relationship between the energetic ({approximately}1MeV) proton intensity (J) and the magnetic compression ratio (C) measured at the trailing edges of corotating interaction regions observed at Ulysses. In general, our results show that the proton intensity was well correlated with the compression ratio, provided that the seed intensity remained constant, consistent with predictions of the Fermi model. Specifically, our results indicate that particles were accelerated to above {approximately}1MeV in energy at or near the trailing edges of the compression regions observed in the midlatitude southern heliosphere, irrespective of whether the bounding reverse shocks were present or not. On the basis of this, we conclude that shock acceleration is probably not the only mechanism by which particles are accelerated to above {approximately}1MeV in energy at compression or interaction regions (CIRs). On the basis of magnetic field measurements obtained near the trailing edges of several midlatitude CIRs, we propose that particles could have been accelerated via the Fermi mechanism by being scattered back and forth across the trailing edges of the compression regions by large-amplitude Alfv{acute e}n waves. Our results also show that the proton intensity was well correlated with the compression ratio during low solar activity periods but was essentially independent of C during periods of high solar activity. We suggest that the correlation between J and C was not observed during solar active periods because of significant variations in the seed intensity that result from sporadic contributions from transient solar events. In contrast, the correlation was observable during quiescent periods probably because contributions from transients had decreased dramatically, which allowed the CIRs to accelerate particles out of a seed population whose intensity remained relatively unperturbed. {copyright} 1998 American Geophysical Union

Desai, M.I.; Marsden, R.G.; Sanderson, T.R. [Space Science Department, European Space Agency, Noordwijk (Netherlands)] [Space Science Department, European Space Agency, Noordwijk (Netherlands); Balogh, A.; Forsyth, R.J. [Blackett Laboratory, Imperial College, London (England)] [Blackett Laboratory, Imperial College, London (England); Gosling, J.T. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

1998-02-01T23:59:59.000Z

182

Acceleration of particles in Gamma Ray sources: Blazars and Gamma Ray Bursts  

Science Journals Connector (OSTI)

The objectives of my talk are to indicate the requirements for particle acceleration for both electrodynamic models and hadronic models in blazars then to propose a relativistic Fermi acceleration process to achieve the goal of UHE Cosmic Ray production in relativistic flows. Relativistic magnetic fronts when they cross each other produce an efficient Fermi process. It is also indicate how forward and backward fronts can be generated. Most of the involved physics also apply to Gamma Ray Bursts provided that they are produced by a magnetically collimated relativistic flow.

Guy Pelletier

2001-01-01T23:59:59.000Z

183

A new expression for the transition rate of an accelerated particle detector  

E-Print Network (OSTI)

We analyse the instantaneous transition rate of an accelerated Unruh-DeWitt particle detector whose coupling to a quantum field on Minkowski space is regularised by a finite spatial profile. We show, under mild technical assumptions, that the zero size limit of the detector response is well defined, independent of the choice of the profile function, and given by a manifestly finite integral formula that no longer involves epsilon-regulators or limits. Applications to specific trajectories are discussed, recovering in particular the thermal result for uniform acceleration. Extensions of the model to de Sitter space are also considered.

J. Louko; A. Satz

2006-11-22T23:59:59.000Z

184

PARTICLE ACCELERATION IN FRAGMENTING PERIODIC RECONNECTING CURRENT SHEETS IN SOLAR FLARES  

SciTech Connect

Proton and electron acceleration in a fragmenting periodic current sheet (CS) is investigated, based on the forced magnetic reconnection scenario. The aim is to understand the role of CS fragmentation in high-energy beam generation in solar flares. We combine magnetohydrodynamics and test-particle models to consider particle trajectories consistent with a time-dependent reconnection model. It is shown that accelerated particles in such a model form two distinct populations. Protons and electrons moving in open magnetic field have energy spectra that are a combination of the initial Maxwellian distribution and a power-law high-energy (E>20 keV) part. The second population contains particles moving in a closed magnetic field around O-points. These particles move predominantly along the guiding field and their energies fall within quite a narrow range between {approx}1 MeV and {approx}10 MeV. It is also found that particles moving in an open magnetic field have a considerably wider pitch-angle distribution.

Gordovskyy, M.; Browning, P. K.; Vekstein, G. E., E-mail: mykola.gordovskyy@manchester.ac.u [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

2010-09-10T23:59:59.000Z

185

3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration  

SciTech Connect

We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occurring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to develop a flexible platform, which can be generalized to include effects such as MFA, and which can be easily adapted to various SNR environments, including Type Ia SNRs, which explode in a constant density medium, and Type II SNRs, which explode in a pre-supernova wind. When applied to a specific SNR, our model will predict cosmic-ray spectra and multi-wavelength morphology in projected images for instruments with varying spatial and spectral resolutions. We show examples of these spectra and images and emphasize the importance of measurements in the hard X-ray, GeV, and TeV gamma-ray bands for investigating key ingredients in the acceleration mechanism, and for deducing whether or not TeV emission is produced by IC from electrons or pion-decay from protons.

Lee, Shiu-Hang; Kamae, Tuneyoshi; Ellison, Donald C.

2008-07-02T23:59:59.000Z

186

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

SciTech Connect

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

Trbojevic, Dejan [BNL Collider-Accelerator Department

2013-10-22T23:59:59.000Z

187

Acceleration-induced scalar field transitions of n-particle multiplicity  

E-Print Network (OSTI)

In this paper we calculate the effect of acceleration on the decay and excitation rates of scalar fields into a final state of arbitrary multiplicity. The analysis is carried out using standard field operators as well as an Unruh-DeWitt detector. Using the equivalence of the two methods, we show how to correctly setup the computation and interpret the results in terms of the particle content of the initial and final state Rindler and Minkowski spacetimes. We find the dominant transition pathway, and thus final state multiplicity, is acceleration dependent. The formalisms developed are then used to analyze the electron and muon system. We compute the transition rates and lifetimes for accelerated electrons and muons as well as the branching fractions for muon decay.

Morgan H. Lynch

2014-06-04T23:59:59.000Z

188

Status of materials handbooks for particle accelerator and nuclear reactor applications  

SciTech Connect

In support of research and development for accelerator applications, a materials handbook was developed in August of 1998 funded by the Accelerator Production of Tritium Project. This handbook, presently called Advanced Fuel Cycle Initiative (AFCI) Materials Handbook, Materials Data for Particle Accelerator Applications, has just issued Revision 5 and contains detailed information showing the effects of irradiation on many properties for a wide variety of materials. Development of a web-accessible materials database for Generation IV Reactor Programs has been ongoing for about three years. This handbook provides a single authoritative source for qualified materials data applicable to all Generation IV reactor concepts. A beta version of this Gen IV Materials Handbook has been completed and is presently under evaluation.

Maloy, Stuart [Los Alamos National Laboratory (LANL); Rogers, Berylene [Los Alamos National Laboratory (LANL); Ren, Weiju [ORNL; Philip, Rittenhouse [Consultant

2008-01-01T23:59:59.000Z

189

A method to simulate linear stability of impulsively accelerated density interfaces in ideal-MHD and gas dynamics  

Science Journals Connector (OSTI)

We present a numerical method to solve the linear stability of impulsively accelerated density interfaces in two dimensions such as those arising in the Richtmyer-Meshkov instability. The method uses an Eulerian approach, and is based on an upwind method ... Keywords: 02.60.Cb, 04.30.Nk, 47.11.Df, 47.20.Cq, 52.57.Fg, Numerical linear stability, Richtmyer-Meshkov, Upwind method

Ravi Samtaney

2009-10-01T23:59:59.000Z

190

Preferential Heating and Acceleration of ? Particles by Alfvén-Cyclotron Waves  

Science Journals Connector (OSTI)

Preferential heating and acceleration of heavy ions in the solar wind and corona represent a long-standing theoretical problem in space physics, and are distinct experimental signatures of kinetic processes occurring in collisionless plasmas. We show that fast and slow ion-acoustic waves (IAW) and transverse waves, driven by Alfvén-cyclotron wave parametric instabilities can selectively destroy the coherent fluid motion of different ion species and, in this way lead to their differential heating and acceleration. Trapping of the more abundant protons by the fast IAW generates a proton beam with drift speed of about the Alfvén speed. Because of their larger mass, ? particles do not become significantly trapped and start, by conservation of total ion momentum, drifting relative to the receding bulk protons. Thus the resulting core protons and the ? particles are differentially heated via pitch-angle scattering.

J. A. Araneda; Y. Maneva; E. Marsch

2009-04-27T23:59:59.000Z

191

Linear interfacial polymerization: Theory and simulations with dissipative particle dynamics  

Science Journals Connector (OSTI)

Step-growth alternating interfacial polymerization between two miscible or immiscible monomer melts is investigated theoretically and by dissipative particle dynamics simulations. In both cases the kinetics for an initially bilayer system passes from the reaction to diffusion control. The polymer composed of immiscible monomers precipitates at the interface forming a film of nearly uniform density. It is demonstrated that the reaction proceeds in a narrow zone which expands much slower than the whole film so that newly formed polymer is extruded from the reaction zone. This concept of “reactive extrusion” is used to analytically predict the degree of polymerization and distribution of all components (monomers polymer and end groups) within the film in close agreement with the simulations. Increasing the comonomer incompatibility leads to thinner and more uniform films with the higher average degree of polymerization. The final product is considerably more polydisperse than expected for the homogeneous step-growth polymerization. The results extend the previous theoretical reports on interfacial polymerization and provide new insights into the internal film structure and polymer characteristics which are important for membrane preparation microencapsulation and 3D printing technologies. A systematic way of mapping the simulation data onto laboratory scales is discussed.

2014-01-01T23:59:59.000Z

192

Gamma-ray novae as probes of relativistic particle acceleration at non-relativistic shocks  

E-Print Network (OSTI)

The Fermi LAT discovery that classical novae produce >100 MeV gamma-rays establishes that shocks and relativistic particle acceleration are key features of these events. These shocks are likely to be radiative due to the high densities of the nova ejecta at early times coincident with the gamma-ray emission. Thermal X-rays radiated behind the shock are absorbed by neutral gas and reprocessed into optical emission, similar to Type IIn (interacting) supernovae. The ratio of gamma-ray and optical luminosities, L_gam/L_opt, thus sets a lower limit on the fraction of the shock power used to accelerate relativistic particles, e_nth. The measured values of L_gam/L_opt for two classical novae, V1324 Sco and V339 Del, constrains e_nth > 1e-2 and > 1e-3, respectively. Inverse Compton models for the gamma-ray emission are disfavored given the low electron acceleration efficiency, e_nth ~ 1e-4-1e-3, inferred from observations of Galactic cosmic rays and particle-in-cell (PIC) numerical simulations. Recent hybrid PIC simu...

Metzger, Brian D; Vurm, Indrek; Hascoet, Romain; Beloborodov, Andrei M; Chomiuk, Laura

2015-01-01T23:59:59.000Z

193

PHYSICAL REVIEW SPECIAL TOPICS -ACCELERATORS AND BEAMS, VOLUME 5, 011001 (2002) Energy doubler for a linear collider  

E-Print Network (OSTI)

, California 90089 W. B. Mori, C. Joshi, R. Hemker, E. S. Dodd, C. E. Clayton, K. A. Marsh, B. Blue, and S. Wang University of California, Los Angeles, Los Angeles, California 90095 R. Assmann, F. J. Decker, M. Hogan, R. Iverson, and D. Walz Stanford Linear Accelerator Center, Stanford University, Stanford

194

Type A Investigation of the Electrical Arc Injury at the Stanford Linear Accelerator Complex on October 11, 2004  

Energy.gov (U.S. Department of Energy (DOE))

On October 11, 2004, at approximately 11:15 am, a subcontractor electrician working at the Stanford Linear Accelerator Center (SLAC) received serious burn injuries requiring hospitalization due to an electrical arc flash that occurred during the installation of a circuit breaker in an energized 480-Volt (V) electrical panel.

195

Novel X-Ray Imaging Opportunities for the RPI Linear Accelerator's Tunable, Quasi-monochromatic X-ray Source  

E-Print Network (OSTI)

Novel X-Ray Imaging Opportunities for the RPI Linear Accelerator's Tunable, Quasi-monochromatic X-ray of an intense, tunable, polarized, and quasi-monochromatic X-ray source has been ongoing at Rensselaer Polytechnic Institute since 2001 [1, 2, 3, 4, 5, 6]. This X-ray source, known as Parametric X-rays (PXR

Danon, Yaron

196

Standard Test Method for Measuring Dose for Use in Linear Accelerator Pulsed Radiation Effects Tests  

E-Print Network (OSTI)

1.1 This test method covers a calorimetric measurement of the total dose delivered in a single pulse of electrons from an electron linear accelerator or a flash X-ray machine (FXR, e-beam mode) used as an ionizing source in radiation-effects testing. The test method is designed for use with pulses of electrons in the energy range from 10 to 50 MeV and is only valid for cases in which both the calorimeter and the test specimen to be irradiated are“thin” compared to the range of these electrons in the materials of which they are constructed. 1.2 The procedure described can be used in those cases in which (1) the dose delivered in a single pulse is 5 Gy (matl) (500 rd (matl)) or greater, or (2) multiple pulses of a lower dose can be delivered in a short time compared to the thermal time constant of the calorimeter. Matl refers to the material of the calorimeter. The minimum dose per pulse that can be acceptably monitored depends on the variables of the particular test, including pulse rate, pulse uniformity...

American Society for Testing and Materials. Philadelphia

2011-01-01T23:59:59.000Z

197

GAMMA-RAY EMISSION OF ACCELERATED PARTICLES ESCAPING A SUPERNOVA REMNANT IN A MOLECULAR CLOUD  

SciTech Connect

We present a model of gamma-ray emission from core-collapse supernovae (SNe) originating from the explosions of massive young stars. The fast forward shock of the supernova remnant (SNR) can accelerate particles by diffusive shock acceleration (DSA) in a cavern blown by a strong, pre-SN stellar wind. As a fundamental part of nonlinear DSA, some fraction of the accelerated particles escape the shock and interact with a surrounding massive dense shell producing hard photon emission. To calculate this emission, we have developed a new Monte Carlo technique for propagating the cosmic rays (CRs) produced by the forward shock of the SNR, into the dense, external material. This technique is incorporated in a hydrodynamic model of an evolving SNR which includes the nonlinear feedback of CRs on the SNR evolution, the production of escaping CRs along with those that remain trapped within the remnant, and the broadband emission of radiation from trapped and escaping CRs. While our combined CR-hydro-escape model is quite general and applies to both core collapse and thermonuclear SNe, the parameters we choose for our discussion here are more typical of SNRs from very massive stars whose emission spectra differ somewhat from those produced by lower mass progenitors directly interacting with a molecular cloud.

Ellison, Donald C. [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States); Bykov, Andrei M., E-mail: don_ellison@ncsu.edu, E-mail: byk@astro.ioffe.ru [Ioffe Institute for Physics and Technology, 194021 St. Petersburg (Russian Federation)

2011-04-20T23:59:59.000Z

198

Review of Heavy-ion Induced Desorption Studies for Particle Accelerators  

E-Print Network (OSTI)

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

Mahner, E

2008-01-01T23:59:59.000Z

199

The Particle Adventure | How do we experiment with tiny particles? |  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerating particles Accelerating particles Accelerating particles It is fairly easy to obtain particles. Physicists get electrons by heating metals; they get protons by robbing hydrogen of its electron; etc. Accelerators speed up charged particles by creating large electric fields which attract or repel the particles. This field is then moved down the accelerator, "pushing" the particles along. In a linear accelerator the field is due to traveling electromagnetic (E-M) waves. When an E-M wave hits a bunch of particles, those in the back get the biggest boost, while those in the front get less of a boost. In this fashion, the particles "ride" the front of the E-M wave like a bunch of surfers. The next page shows this process in an easier to understand animation

200

THE INFLUENCE OF THE MASS RATIO ON THE ACCELERATION OF PARTICLES BY FILAMENTATION INSTABILITIES  

SciTech Connect

Almost all sources of high-energy particles and photons are associated with jet phenomena. Prominent sources of such highly relativistic outflows are pulsar winds, active galactic nuclei (AGNs), and gamma-ray bursts. The current understanding of these jets assumes diluted plasmas which are best described as kinetic phenomena. In this kinetic description, particle acceleration to ultrarelativistic speeds can occur in completely unmagnetized and neutral plasmas through insetting effects of instabilities. Even though the morphology and nature of particle spectra are understood to a certain extent, the composition of the jets is not known yet. While Poynting-flux-dominated jets (e.g., occurring in pulsar winds) are certainly composed of electron-positron plasmas, the understanding of the governing physics in AGN jets is mostly unclear. In this paper, we investigate how the constituting elements of an electron-positron-proton plasma behave differently under the variation of the fundamental mass ratio m{sub p} /m{sub e}. We initially studied unmagnetized counterstreaming plasmas using fully relativistic three-dimensional particle-in-cell simulations to investigate the influence of the mass ratio on particle acceleration and magnetic field generation in electron-positron-proton plasmas. We covered a range of mass ratios m{sub p}/m{sub e} between 1 and 100 with a particle number composition of n{sub p}{sup +}/ n{sub e}{sup +} of 1 in one stream, therefore called the pair-proton stream. Protons are injected in the other one, therefore from now on called the proton stream, whereas electrons are present in both to guarantee charge neutrality in the simulation box. We find that with increasing proton mass the instability takes longer to develop and for mass ratios >20 the particles seem to be accelerated in two phases which can be accounted for by the individual instabilities of the different species. This means that for high mass ratios the coupling between electrons/positrons and the heavier protons, which occurs in low mass ratios, disappears.

Burkart, Thomas; Elbracht, Oliver; Ganse, Urs; Spanier, Felix, E-mail: fspanier@astro.uni-wuerzburg.d [Lehrstuhl fuer Astronomie, Universitaet Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany)

2010-09-10T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
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201

FPGA-based Particle Recognition in the HADES Abstract--Modern FPGA technologies are often employed in nuclear and particle physics experimental facilities to accelerate  

E-Print Network (OSTI)

1 FPGA-based Particle Recognition in the HADES Experiment Abstract--Modern FPGA technologies-specific computation. We present the particle recognition computation for the HADES experiment in this article of commodity PCs for the HADES experiment. Index Terms--reconfigurable computing, FPGA accelerator, pattern

Jantsch, Axel

202

A GEOMETRIC DERIVATION OF THE LINEAR BOLTZMANN EQUATION FOR A PARTICLE INTERACTING WITH A  

E-Print Network (OSTI)

] the radiative transport equation in the spatially homogenous case. Later Ho, Landau and Wilkins studied in [29 Boltzmann equation was derived in the radiative transport limit by Bal, Papanicolaou and Ryzhik [5A GEOMETRIC DERIVATION OF THE LINEAR BOLTZMANN EQUATION FOR A PARTICLE INTERACTING WITH A GAUSSIAN

Paris-Sud XI, Université de

203

The colliding-wind binary WR140: the particle acceleration laboratory  

E-Print Network (OSTI)

WR+O star binary systems exhibit synchrotron emission arising from relativistic electrons accelerated where the wind of the WR star and that of its massive binary companion collide - the wind-collision region (WCR). These ``colliding-wind'' binaries (CWB), provide an excellent laboratory for the study of particle acceleration, with the same physical processes as observed in SNRs, but at much higher mass, photon and magnetic energy densities. WR140 is the best studied CWB, and high resolution radio observations permit a determination of several system parameters, particularly orbit inclination and distance, that are essential constraints for newly developed models of CWBs. We show a model fit to the radio data at orbital phase 0.9, and show how these models may be used to predict the high energy emission from WR140.

S. M. Dougherty; J. M. Pittard

2005-10-18T23:59:59.000Z

204

Improving the design and analysis of superconducting magnets for particle accelerators  

SciTech Connect

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

Gupta, R.C. [Univ. of Rajasthan, Jaipur (India). Dept. of Physics]|[Brookhaven National Lab., Upton, NY (United States). Magnet Div.

1996-11-01T23:59:59.000Z

205

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

E-Print Network (OSTI)

collider," in Advanced Accelerator Concepts, edited by C .Considerations for Plasma Accelerators Driven by Lasers orUSA Abstract. Plasma accelerators may be driven by the

Schroeder, C. B.

2011-01-01T23:59:59.000Z

206

Particle acceleration and transport in reconnecting twisted loops in a stratified atmosphere  

E-Print Network (OSTI)

Twisted coronal loops should be ubiquitous in the solar corona. Twisted magnetic fields contain excess magnetic energy, which can be released during magnetic reconnection, causing solar flares. The aim of this work is to investigate magnetic reconnection, and particle acceleration and transport in kink-unstable twisted coronal loops, with a focus on the effects of resistivity, loop geometry and atmospheric stratification. Another aim is to perform forward-modelling of bremsstrahlung emission and determine the structure of hard X-ray sources. We use a combination of magnetohydrodynamic (MHD) and test-particle methods. First, the evolution of the kinking coronal loop is considered using resistive MHD model, incorporating atmospheric stratification and loop curvature. Then, the obtained electric and magnetic fields and density distributions are used to calculate electron and proton trajectories using a guiding-centre approximation, taking into account Coulomb collisions. It is shown that electric fields in twist...

Gordovskyy, Mykola; Kontar, Eduard; Bian, Nicolas

2015-01-01T23:59:59.000Z

207

Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants  

SciTech Connect

I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and {gamma}-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification.The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations.Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

Vink, Jacco [Astronomical Institute Utrecht, Utrecht University, P.O. Box 80000, 3508TA Utrecht (Netherlands)

2009-05-11T23:59:59.000Z

208

LASER ACCELERATORS  

E-Print Network (OSTI)

UNIVERSITY OF CALIFORNIA Accelerator & Fusion Researchat the 1983 Particle Accelerator Conference, Santa Fe, NM,March 21-23, 1983 LASER ACCELERATORS A.M. Sessler TWO-WEEK

Sessler, A.M.

2008-01-01T23:59:59.000Z

209

Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasma  

SciTech Connect

Bulk ion acceleration and particle heating during magnetic reconnection are studied in the collisionless plasma of the Magnetic Reconnection Experiment (MRX). The plasma is in the two-fluid regime, where the motion of the ions is decoupled from that of the electrons within the ion diffusion region. The reconnection process studied here is quasi-symmetric since plasma parameters such as the magnitude of the reconnecting magnetic field, the plasma density, and temperature are compatible on each side of the current sheet. Our experimental data show that the in-plane (Hall) electric field plays a key role in ion heating and acceleration. The electrostatic potential that produces the in-plane electric field is established by electrons that are accelerated near the electron diffusion region. The in-plane profile of this electrostatic potential shows a “well” structure along the direction normal to the reconnection current sheet. This well becomes deeper and wider downstream as its boundary expands along the separatrices where the in-plane electric field is strongest. Since the in-plane electric field is 3–4 times larger than the out-of-plane reconnection electric field, it is the primary source of energy for the unmagnetized ions. With regard to ion acceleration, the Hall electric field causes ions near separatrices to be ballistically accelerated toward the outflow direction. Ion heating occurs as the accelerated ions travel into the high pressure downstream region. This downstream ion heating cannot be explained by classical, unmagnetized transport theory; instead, we conclude that ions are heated by re-magnetization of ions in the reconnection exhaust and collisions. Two-dimensional (2-D) simulations with the global geometry similar to MRX demonstrate downstream ion thermalization by the above mechanisms. Electrons are also significantly heated during reconnection. The electron temperature sharply increases across the separatrices and peaks just outside of the electron diffusion region. Unlike ions, electrons acquire energy mostly from the reconnection electric field, and the energy gain is localized near the X-point. However, the increase in the electron bulk flow energy remains negligible. These observations support the assertion that efficient electron heating mechanisms exist around the electron diffusion region and that the heat generated there is quickly transported along the magnetic field due to the high parallel thermal conductivity of electrons. Classical Ohmic dissipation based on the perpendicular Spitzer resistivity is too small to balance the measured heat flux, indicating the presence of anomalous electron heating.

Yoo, Jongsoo; Yamada, Masaaki; Ji, Hantao; Jara-Almonte, Jonathan; Myers, Clayton E. [Center for Magnetic Self-Organization, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Center for Magnetic Self-Organization, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2014-05-15T23:59:59.000Z

210

Relative Humidity in Limited Streamer Tubes for Stanford Linear Accelerator Center's BaBar Detector  

SciTech Connect

The BABAR Detector at the Stanford Linear Accelerator Center studies the decay of B mesons created in e{sup +}e{sup -} collisions. The outermost layer of the detector, used to detect muons and neutral hadrons created during this process, is being upgraded from Resistive Plate Chambers (RPCs) to Limited Streamer Tubes (LSTs). The standard-size LST tube consists of eight cells, where a silver-plated wire runs down the center of each. A large potential difference is placed between the wires and ground. Gas flows through a series of modules connected with tubing, typically four. LSTs must be carefully tested before installation, as it will be extremely difficult to repair any damage once installed in the detector. In the testing process, the count rate in most modules showed was stable and consistent with cosmic ray rate over an approximately 500 V operating range between 5400 to 5900 V. The count in some modules, however, was shown to unexpectedly spike near the operation point. In general, the modules through which the gas first flows did not show this problem, but those further along the gas chain were much more likely to do so. The suggestion was that this spike was due to higher humidity in the modules furthest from the fresh, dry inflowing gas, and that the water molecules in more humid modules were adversely affecting the modules' performance. This project studied the effect of humidity in the modules, using a small capacitive humidity sensor (Honeywell). The sensor provided a humidity-dependent output voltage, as well as a temperature measurement from a thermistor. A full-size hygrometer (Panametrics) was used for testing and calibrating the Honeywell sensors. First the relative humidity of the air was measured. For the full calibration, a special gas-mixing setup was used, where relative humidity of the LST gas mixture could be varied from almost dry to almost fully saturated. With the sensor calibrated, a set of sensors was used to measure humidity vs. time in the LSTs. The sensors were placed in two sets of LST modules, one gas line flowing through each set. These modules were tested for count rate v. voltage while simultaneously measuring relative humidity in each module. One set produced expected readings, while the other showed the spike in count rate. The relative humidity in the two sets of modules looked very similar, but it rose significantly for modules further along the gas chain.

Lang, M.I.; /MIT; Convery, M.; /SLAC; Menges, W.; /Queen Mary, U. of London

2005-12-15T23:59:59.000Z

211

Commissioning of the Varian TrueBeam linear accelerator: A multi-institutional study  

SciTech Connect

Purpose: Latest generation linear accelerators (linacs), i.e., TrueBeam (Varian Medical Systems, Palo Alto, CA) and its stereotactic counterpart, TrueBeam STx, have several unique features, including high-dose-rate flattening-filter-free (FFF) photon modes, reengineered electron modes with new scattering foil geometries, updated imaging hardware/software, and a novel control system. An evaluation of five TrueBeam linacs at three different institutions has been performed and this work reports on the commissioning experience. Methods: Acceptance and commissioning data were analyzed for five TrueBeam linacs equipped with 120 leaf (5 mm width) MLCs at three different institutions. Dosimetric data and mechanical parameters were compared. These included measurements of photon beam profiles (6X, 6XFFF, 10X, 10XFFF, 15X), photon and electron percent depth dose (PDD) curves (6, 9, 12 MeV), relative photon output factors (Scp), electron cone factors, mechanical isocenter accuracy, MLC transmission, and dosimetric leaf gap (DLG). End-to-end testing and IMRT commissioning were also conducted. Results: Gantry/collimator isocentricity measurements were similar (0.27-0.28 mm), with overall couch/gantry/collimator values of 0.46-0.68 mm across the three institutions. Dosimetric data showed good agreement between machines. The average MLC DLGs for 6, 10, and 15 MV photons were 1.33 {+-} 0.23, 1.57 {+-} 0.24, and 1.61 {+-} 0.26 mm, respectively. 6XFFF and 10XFFF modes had average DLGs of 1.16 {+-} 0.22 and 1.44 {+-} 0.30 mm, respectively. MLC transmission showed minimal variation across the three institutions, with the standard deviation <0.2% for all linacs. Photon and electron PDDs were comparable for all energies. 6, 10, and 15 MV photon beam quality, %dd(10){sub x} varied less than 0.3% for all linacs. Output factors (Scp) and electron cone factors agreed within 0.27%, on average; largest variations were observed for small field sizes (1.2% coefficient of variation, 10 MV, 2 Multiplication-Sign 2 cm{sup 2}) and small cone sizes (<1% coefficient of variation, 6 Multiplication-Sign 6 cm{sup 2} cone), respectively. Conclusions: Overall, excellent agreement was observed in TrueBeam commissioning data. This set of multi-institutional data can provide comparison data to others embarking on TrueBeam commissioning, ultimately improving the safety and quality of beam commissioning.

Glide-Hurst, C.; Bellon, M.; Wen, N.; Zhao, B.; Chetty, I. J. [Department of Radiation Oncology, Henry Ford Health Systems, Detroit, Michigan 48202 (United States); Foster, R.; Speiser, M.; Solberg, T. [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75235 (United States); Altunbas, C.; Westerly, D.; Miften, M. [Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States); Altman, M. [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States)

2013-03-15T23:59:59.000Z

212

SuperHILAC: Heavy-ion linear accelerator: Summary of capabilities, facilities, operations, and research  

SciTech Connect

This report consists of a description of the accelerator facilities and a review of research programs being conducted there. Lists of SuperHILAC researchers and publications are also given.

McDonald, R.J. (ed.)

1987-09-01T23:59:59.000Z

213

Design and Factory Test of the E /E- Frascati Linear Accelerator for DAFNE  

SciTech Connect

The electron-positron accelerator for the DAFNE project has been built and is in test at Titan Beta in Dublin, CA. This S-Band RF linac system utilizes four 45 MW sledded klystrons and 16-3 m accelerating structures to achieve the required performance. It delivers a 4 ampere electron beam to the positron converter and accelerates the resulting positrons to 550 MeV. The converter design uses a 4.3T pulsed tapered flux compressor along with a pseudo-adiabatic tapered field to a 5 KG solenoid over the first two positron accelerating sections. Quadrupole focusing is used after 100 MeV. The system performance is given in Table 1. This paper briefly describes the design and development of the various subassemblies in this system and gives the initial factory test data.

Anamkath, H.; Lyons, S.; Nett, D.; Treas, P.; Whitham, K.; Zante, T.; /Titan Beta, Dublin; Miller, R.; /Titan Beta, Dublin /SLAC; Boni, R.; Hsieh, H.; Sannibale, F.; Vescovi, M.; Vignola, G.; /Frascati

2011-11-28T23:59:59.000Z

214

Acceleration  

NLE Websites -- All DOE Office Websites (Extended Search)

Acceleration Acceleration of porous media simulations on the Cray XE6 platform Kirsten M. Fagnan, Michael Lijewski, George Pau, Nicholas J. Wright Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley, CA 94720 May 18, 2011 1 Introduction In this paper we investigate the performance of the Porous Media with Adaptive Mesh Refinment (PMAMR) code which was developed in the Center for Computational Science and Engineering at Lawrence Berkeley National Laboratory. This code is being used to model carbon sequestration and contaminant transport as part of the Advanced Simulation Capability for Environmental Management (ASCEM) project. The goal of the ASCEM project is to better understand and quantify flow and contaminant transport behavior in complex geological systems. It will also address the long-term performance of engineered components including cementitious materials in

215

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

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

216

Linear accelerator design study with direct plasma injection scheme for warm dense matter  

SciTech Connect

Warm Dense Matter (WDM) is a challenging science field, which is related to heavy ion inertial fusion and planetary science. It is difficult to expect the behavior because the state with high density and low temperature is completely different from ideal condition. The well-defined WDM generation is required to understand it. Moderate energy ion beams ({approx} MeV/u) slightly above Bragg peak is an advantageous method for WDM because of the uniform energy deposition. Direct Plasma Injection Scheme (DPIS) with a Interdigital H-mode (IH) accelerator has a potential for the beam parameter. We show feasible parameters of the IH accelerator for WDM. WDM physics is a challenging science and is strongly related to Heavy Ion Fusion science. WDM formation by Direct Plasma Injection Scheme (DPIS) with IH accelerator, which is a compact system, is proposed. Feasible parameters for IH accelerator are shown for WDM state. These represents that DPIS with IH accelerator can access a different parameter region of WDM.

Kondo, K.; Kanesue, T; Okamura, M.

2011-03-28T23:59:59.000Z

217

Design Concepts for RF-DC Conversion in Particle Accelerator Systems  

E-Print Network (OSTI)

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

Caspers, F; Grudiev, A; Sapotta, H

2010-01-01T23:59:59.000Z

218

Production of .sup.64 Cu and other radionuclides using a charged-particle accelerator  

DOE Patents (OSTI)

Radionuclides are produced according to the present invention at commercially significant yields and at specific activities which are suitable for use in radiodiagnostic agents such as PET imaging agents and radiotherapeutic agents and/or compositions. In the method and system of the present invention, a solid target having an isotopically enriched target layer electroplated on an inert substrate is positioned in a specially designed target holder and irradiated with a charged-particle beam. The beam is preferably generated using an accelerator such as a biomedical cyclotron at energies ranging from about 5 MeV to about 25 MeV. The target is preferably directly irradiated, without an intervening attenuating foil, and with the charged particle beam impinging an area which substantially matches the target area. The irradiated target is remotely and automatically transferred from the target holder, preferably without transferring any target holder subassemblies, to a conveyance system which is preferably a pneumatic or hydraulic conveyance system, and then further transferred to an automated separation system. The system is effective for processing a single target or a plurality of targets. After separation, the unreacted target material can be recycled for preparation of other targets. In a preferred application of the invention, a biomedical cyclotron has been used to produce over 500 mCi of .sup.64 Cu having a specific activity of over 300 mCi/.mu.g Cu according to the reaction .sup.64 Ni(p,n).sup.64 Cu. These results indicate that accelerator-produced .sup.64 Cu is suitable for radiopharmaceutical diagnostic and therapeutic applications.

Welch, Michael J. (Creve Couer, MO); McCarthy, Deborah W. (Maryland Heights, MO); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

2000-01-01T23:59:59.000Z

219

Alignment tolerance of accelerating structures and corrections for future linear colliders  

SciTech Connect

The alignment tolerance of accelerating structures is estimated by tracking simulations. Both single-bunch and multi-bunch effects are taken into account. Correction schemes for controlling the single and multi-bunch emittance growth in the case of large misalignment are also tested by simulations.

Kubo, K.; Adolphsen, C.; Bane, K.L.F.; Raubenheimer, T.O.; Thompson, K.A.

1995-06-01T23:59:59.000Z

220

SIMULATIONS OF PARTICLE ACCELERATION BEYOND THE CLASSICAL SYNCHROTRON BURNOFF LIMIT IN MAGNETIC RECONNECTION: AN EXPLANATION OF THE CRAB FLARES  

SciTech Connect

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

Cerutti, B.; Werner, G. R.; Uzdensky, D. A. [Center for Integrated Plasma Studies, Physics Department, University of Colorado, UCB 390, Boulder, CO 80309-0390 (United States); Begelman, M. C., E-mail: benoit.cerutti@colorado.edu, E-mail: greg.werner@colorado.edu, E-mail: uzdensky@colorado.edu, E-mail: mitch@jila.colorado.edu [JILA, University of Colorado and National Institute of Standards and Technology, UCB 440, Boulder, CO 80309-0440 (United States)

2013-06-20T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Production and acceleration of tracer encapsulated solid pellets for particle transport diagnostics  

Science Journals Connector (OSTI)

A new method for producing a tracer-encapsulated solid pellet (TESPEL) has been developed for a local deposition of the tracer ions in the core plasma and an accurate measurement of the particle transport. The method allows manufacturing of TESPELs in the form of polystyrene shells containing lithium hydride inside as a tracer. The TESPEL acceleration has been successfully performed and photos of the pellets in flight confirmed the TESPEL integrity. For the pellets with diameter 300–400 ? m and wall thickness 40–50 ? m the pellet fragility becomes insignificant. Calculation of the TESPEL ablation rate has showed that the achieved pellet velocities and sizes are appropriate for the injection into a medium size plasma. It was proposed to fractionate the tracer contents in order to provide better localization of the deposited tracer ions in the plasma. The data obtained in these experiments have proved that injection of the TESPEL made from the plastic shells can be a promising tool for the particle transport diagnostics.

K. V. Khlopenkov; S. Sudo

1998-01-01T23:59:59.000Z

222

Beam dynamics study of a 30?MeV electron linear accelerator to drive a neutron source  

SciTech Connect

An experimental neutron facility based on 32?MeV/18.47?kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E?=?30?MeV, P?=?18?kW, dE/E?particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2?/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32?MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5?×?10{sup 11}?n/cm{sup 2}/s/mA. Future development will be the real design of a 30?MeV electron linac based on S band traveling wave.

Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik, E-mail: hskang@postech.ac.kr [Pohang Accelerator Laboratory, San31, Hyoja-dong, Pohang, Gyeongbuk 790-784 (Korea, Republic of)

2014-02-14T23:59:59.000Z

223

Optimal linear phase FIR filter design using particle swarm optimization with constriction factor and inertia weight approach with wavelet mutation  

Science Journals Connector (OSTI)

In this paper, Particle Swarm Optimization with Constriction Factor and Inertia Weight Approach is hybridized with Wavelet Mutation PSOCFIWA-WM strategy for the optimal design of linear phase FIR filters. Real coded genetic algorithm RGA, particle swarm ... Keywords: Band Pass, Band Stop, Convergence, Evolutionary Optimization Technique, Fir Filter, High Pass, Low Pass, Magnitude Response, Pso, Psocfiwa, Psocfiwa-Wm, Rga

S. K. Saha; R. Kar; D. Mandal; S. P. Ghoshal

2014-04-01T23:59:59.000Z

224

Recent results and future challenges for large scale Particle-In-Cell simulations of plasma-based accelerator concepts  

SciTech Connect

The concept and designs of plasma-based advanced accelerators for high energy physics and photon science are modeled in the SciDAC COMPASS project with a suite of Particle-In-Cell codes and simulation techniques including the full electromagnetic model, the envelope model, the boosted frame approach and the quasi-static model. In this paper, we report the progress of the development of these models and techniques and present recent results achieved with large-scale parallel PIC simulations. The simulation needs for modeling the plasma-based advanced accelerator at the energy frontier is discussed and a path towards this goal is outlined.

Huang, C.; An, W.; Decyk, V.K.; Lu, W.; Mori, W.B.; Tsung, F.S.; Tzoufras, M.; Morshed, S.; Antomsen, T.; Feng, B.; Katsouleas, T; Fonseca, R.A.; Martins, S.F.; Vieira, J.; Silva, L.O.; Geddes, C.G.R.; Cormier-Michel, E; Vay, J.-L.; Esarey, E.; Leemans, W.P.; Bruhwiler, D.L.; Cowan, B.; Cary, J.R.; Paul, K.

2009-05-01T23:59:59.000Z

225

Accelerator and Beam Science, ABS, Accelerator Operations and Technology,  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerator Concepts Accelerator Concepts Injectors Operations Physics CONTACTS Group Leader Robert Garnett Deputy Group Leader Kenneth Johnson Office Administrator Monica Sanchez Phone: (505) 667-2846 Put a short description of the graphic or its primary message here Accelerator and Beam Science The Accelerator and Beam Science (AOT-ABS) Group at Los Alamos addresses physics aspects of the driver accelerator for the LANSCE spallation neutron source and related topics. These activities are wide ranging and include generating negative and positive ions in plasma ion sources, creating ion beams from these particles, accelerating the ion beams in linear accelerator structures up to an energy of 800 MeV, compressing the negative hydrogen beam to packets of sub-microsecond duration and accumulating beam current in the Proton Storage Ring, and

226

E-157: A 1.4-m-long plasma wake field acceleration experiment using a 30 GeV electron beam from the Stanford Linear Accelerator  

E-Print Network (OSTI)

-long bunch is propagated through a 1.4-m-long lithium plasma of density up to 2 1014 e /cm3 . The initial- modulated wake field accelerator7 have accelerated electrons with impressive gradients, much in excess of 1 acceleration with gradients in excess of 100 MeV/m over a distance greater than 1 m. The experiment called E

227

Nanoscale Imaging of Airborne Particles Mike Bogan Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road,  

NLE Websites -- All DOE Office Websites (Extended Search)

Diagnostics with an X-ray Laser? Lessons from the First Diagnostics with an X-ray Laser? Lessons from the First Nanoscale Imaging of Airborne Particles Mike Bogan Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA What does airborne particulate matter look like? How do we develop quantitative descriptors for particles of complex morphology? These challenges were highlighted in the NIST workshop report "Aerosol Metrology Needs for Climate Science" (Dec, 2011). Sure, we can capture aerosol particles on surfaces - removing them from their airborne state - and probe them with high resolution optical and chemical imaging tools, but what information do we lose about the airborne particles? How can we follow dynamics? In this talk we will explore these very basic questions and their importance to combustion

228

COLLECTIVE PHENOMENA IN ACCELERATORS  

E-Print Network (OSTI)

Proc. 1971 Particle Accelerator Conference, IEEE Trans. onConference on High-Energy Accelerators) 1971 (CERN, Geneva,and P. R. Zenkevich, Particle Accelerators b 1 (1972). M. S.

Sessler, Andrew M.

2008-01-01T23:59:59.000Z

229

E-Print Network 3.0 - accelerated 56fe particles Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Nevis Laboratories, Radiological Research Accelerator Facility Collection: Fission and Nuclear Technologies ; Biology and Medicine 2 Characterization of proton and heavier ion...

230

Fermilab | Illinois Accelerator Research Center | Accelerators...  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerators and Society Physicists have been inventing new types of accelerators to propel charged particles to higher and higher energies for more than 80 years. Today, besides...

231

Particle Physics Education Sites  

NLE Websites -- All DOE Office Websites (Extended Search)

쭺-¶ 쭺-¶ Particle Physics Education Sites ¡]¥H¤U¬°¥~¤åºô¯¸¡^ quick reference Education and Information - National Laboratory Education Programs - Women and Minorities in Physics - Other Physics Sites - Physics Alliance - Accelerators at National Laboratories icon Particle Physics Education and Information sites: top Introduction: The Particle Adventure - an interactive tour of particle physics for everyone: the basics of theory and experiment. Virtual Visitor Center of the Stanford Linear Accelerator Center. Guided Tour of Fermilab, - overviews of several aspects of Particle Physics. Also check out Particle Physics concepts. Probing Particles - a comprehensive and straight-forward introduction to particle physics. Big Bang Science - approaches particle physics starting from the theoretical origin of the universe.

232

Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered particle injection*  

E-Print Network (OSTI)

Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered; accepted 18 February 1998 Plasma-based accelerators are discussed in which high-power short pulse lasers are the power source, suitably tailored plasma structures provide guiding of the laser beam and support large

Wurtele, Jonathan

233

Image-guided radiotherapy for prostate cancer by CT-linear accelerator combination: Prostate movements and dosimetric considerations  

SciTech Connect

Purpose: Multiple studies have indicated that the prostate is not stationary and can move as much as 2 cm. Such prostate movements are problematic for intensity-modulated radiotherapy, with its associated tight margins and dose escalation. Because of these intrinsic daily uncertainties, a relative generous 'margin' is necessary to avoid marginal misses. Using the CT-linear accelerator combination in the treatment suite (Primatom, Siemens), we found that the daily intrinsic prostate movements can be easily corrected before each radiotherapy session. Dosimetric calculations were performed to evaluate the amount of discrepancy of dose to the target if no correction was done for prostate movement. Methods and materials: The Primatom consists of a Siemens Somatom CT scanner and a Siemens Primus linear accelerator installed in the same treatment suite and sharing a common table/couch. The patient is scanned by the CT scanner, which is movable on a pair of horizontal rails. During scanning, the couch does not move. The exact location of the prostate, seminal vesicles, and rectum are identified and localized. These positions are then compared with the planned positions. The daily movement of the prostate and rectum were corrected for and a new isocenter derived. The patient was treated immediately using the new isocenter. Results: Of the 108 patients with primary prostate cancer studied, 540 consecutive daily CT scans were performed during the last part of the cone down treatment. Of the 540 scans, 46% required no isocenter adjustments for the AP-PA direction, 54% required a shift of {>=}3 mm, 44% required a shift of >5 mm, and 15% required a shift of >10 mm. In the superoinferior direction, 27% required a shift of >3 mm, 25% required a shift of >5 mm, and 4% required a shift of >10 mm. In the right-left direction, 34% required a shift of >3 mm, 24% required a shift of >5 mm, and 5% required a shift of >10 mm. Dosimetric calculations for a typical case of prostate cancer using intensity-modulated radiotherapy with 5-mm margin coverage from the clinical target volume (prostate gland) was performed. With a posterior shift of 10 mm for the prostate, the dose coverage dropped from 95-107% to 71-100% coverage. Conclusion: We have described a technique that corrects for the daily prostate motion, allowing for extremely precise prostate cancer treatment. This technique has significant implications for dose escalation and for decreasing rectal complications in the treatment of prostate cancer.

Wong, James R. [Carol G. Simon Cancer Center, Morristown Memorial Hospital/Atlantic Health System, Morristown, NJ (United States); Department of Radiation Oncology, New York Presbyterian Hospital, Columbia University College of Physicians and Surgeons, New York, NY (United States); Grimm, Lisa [Carol G. Simon Cancer Center, Morristown Memorial Hospital/Atlantic Health System, Morristown, NJ (United States); Uematsu, Minoru [National Defense Medical College, Namiki, Tokorozawa (Japan); Oren, Reva [Carol G. Simon Cancer Center, Morristown Memorial Hospital/Atlantic Health System, Morristown, NJ (United States); Cheng, C.W. [Carol G. Simon Cancer Center, Morristown Memorial Hospital/Atlantic Health System, Morristown, NJ (United States); Merrick, Scott; Schiff, Peter [Department of Radiation Oncology, New York Presbyterian Hospital, Columbia University College of Physicians and Surgeons, New York, NY (United States)

2005-02-01T23:59:59.000Z

234

Three-dimensional, Time-Resolved, Intrafraction Motion Monitoring Throughout Stereotactic Liver Radiation Therapy on a Conventional Linear Accelerator  

SciTech Connect

Purpose: To investigate the time-resolved 3-dimensional (3D) internal motion throughout stereotactic body radiation therapy (SBRT) of tumors in the liver using standard x-ray imagers of a conventional linear accelerator. Methods and Materials: Ten patients with implanted gold markers received 11 treatment courses of 3-fraction SBRT in a stereotactic body-frame on a conventional linear accelerator. Two pretreatment and 1 posttreatment cone-beam computed tomography (CBCT) scans were acquired during each fraction. The CBCT projection images were used to estimate the internal 3D marker motion during CBCT acquisition with 11-Hz resolution by a monoscopic probability-based method. Throughout the treatment delivery by conformal or volumetric modulated arc fields, simultaneous MV portal imaging (8 Hz) and orthogonal kV imaging (5 Hz) were applied to determine the 3D marker motion using either MV/kV triangulation or the monoscopic method when marker segmentation was unachievable in either MV or kV images. The accuracy of monoscopic motion estimation was quantified by also applying monoscopic estimation as a test for all treatments during which MV/kV triangulation was possible. Results: Root-mean-square deviations between monoscopic estimations and triangulations were less than 1.0 mm. The mean 3D intrafraction and intrafield motion ranges during liver SBRT were 17.6 mm (range, 5.6-39.5 mm) and 11.3 mm (2.1-35.5mm), respectively. The risk of large intrafraction baseline shifts correlated with intrafield respiratory motion range. The mean 3D intrafractional marker displacement relative to the first CBCT was 3.4 mm (range, 0.7-14.5 mm). The 3D displacements exceeded 8.8 mm 10% of the time. Conclusions: Highly detailed time-resolved internal 3D motion was determined throughout liver SBRT using standard imaging equipment. Considerable intrafraction motion was observed. The demonstrated methods provide a widely available approach for motion monitoring that, combined with motion-adaptive treatment techniques, has the potential to improve the accuracy of radiation therapy for moving targets.

Worm, Esben S., E-mail: esbeworm@rm.dk [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Institute of Clinical Medicine, Aarhus University (Denmark); Høyer, Morten; Fledelius, Walter [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark)] [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Poulsen, Per R. [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark) [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Institute of Clinical Medicine, Aarhus University (Denmark)

2013-05-01T23:59:59.000Z

235

A CHANDRA VIEW OF NON-THERMAL EMISSION IN THE NORTHWESTERN REGION OF SUPERNOVA REMNANT RCW 86: PARTICLE ACCELERATION AND MAGNETIC FIELDS  

E-Print Network (OSTI)

The shocks of supernova remnants are believed to accelerate particles to cosmic ray (CR) energies. The amplification of the magnetic field due to CRs propagating in the shock region is expected to have an impact on both ...

Castro, Daniel

236

Time dependence of particle creation from accelerating mirrors Michael R. R. Good*  

E-Print Network (OSTI)

time resolution of the particle production process can be obtained. DOI: 10.1103/PhysRevD.88 that has been largely unexplored is the study of the time dependence of the particle production process dependence of creation. One way to explore the time dependence of particle production is through the use

Anderson, Paul R.

237

Argonne Accelerator Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

Useful Links Useful Links Argonne National Laboratory Accelerator Sites Conferences Advanced Photon Source (APS) Argonne Wakefield Accelerator (AWA) Argonne Tandem Linear Accelerator System (ATLAS) High Energy Physics Division RIA (????) Link to JACoW (Joint Accelerator Conferences Website) Fermi National Accelerator Laboratory Fermilab-Argonne Collaboration Accelerator Physics Center Workshops Other Accelerator Institutes Energy Recovering Linacs Center for Advance Studies of Accelerators (Jefferson Labs) Center for Beam Physics (LBNL) Accelerator Test Facility (BNL) The Cockcroft Institute (Daresbury, UK) John Adams Institute (Rutherford, UK) ERL2009 to be held at Cornell ERL2007 ERL2005 DOE Laboratory with Accelerators Fermilab Stanford Linear Accelerator Center Brookhaven National Laboratory

238

Experience of micromultileaf collimator linear accelerator based single fraction stereotactic radiosurgery: Tumor dose inhomogeneity, conformity, and dose fall off  

SciTech Connect

Purpose: Sharp dose fall off outside a tumor is essential for high dose single fraction stereotactic radiosurgery (SRS) plans. This study explores the relationship among tumor dose inhomogeneity, conformity, and dose fall off in normal tissues for micromultileaf collimator (mMLC) linear accelerator (LINAC) based cranial SRS plans. Methods: Between January 2007 and July 2009, 65 patients with single cranial lesions were treated with LINAC-based SRS. Among them, tumors had maximum diameters {<=}20 mm: 31; between 20 and 30 mm: 21; and >30 mm: 13. All patients were treated with 6 MV photons on a Trilogy linear accelerator (Varian Medical Systems, Palo Alto, CA) with a tertiary m3 high-resolution mMLC (Brainlab, Feldkirchen, Germany), using either noncoplanar conformal fixed fields or dynamic conformal arcs. The authors also created retrospective study plans with identical beam arrangement as the treated plan but with different tumor dose inhomogeneity by varying the beam margins around the planning target volume (PTV). All retrospective study plans were normalized so that the minimum PTV dose was the prescription dose (PD). Isocenter dose, mean PTV dose, RTOG conformity index (CI), RTOG homogeneity index (HI), dose gradient index R{sub 50}-R{sub 100} (defined as the difference between equivalent sphere radius of 50% isodose volume and prescription isodose volume), and normal tissue volume (as a ratio to PTV volume) receiving 50% prescription dose (NTV{sub 50}) were calculated. Results: HI was inversely related to the beam margins around the PTV. CI had a ''V'' shaped relationship with HI, reaching a minimum when HI was approximately 1.3. Isocenter dose and mean PTV dose (as percentage of PD) increased linearly with HI. R{sub 50}-R{sub 100} and NTV{sub 50} initially declined with HI and then reached a plateau when HI was approximately 1.3. These trends also held when tumors were grouped according to their maximum diameters. The smallest tumor group (maximum diameters {<=}20 mm) had the most HI dependence for dose fall off. For treated plans, CI averaged 2.55{+-}0.79 with HI 1.23{+-}0.06; the average R{sub 50}-R{sub 100} was 0.41{+-}0.08, 0.55{+-}0.10, and 0.65{+-}0.09 cm, respectively, for tumors {<=}20 mm, between 20 and 30 mm, and >30 mm. Conclusions: Tumor dose inhomogeneity can be used as an important and convenient parameter to evaluate mMLC LINAC-based SRS plans. Sharp dose fall off in the normal tissue is achieved with sufficiently high tumor dose inhomogeneity. By adjusting beam margins, a homogeneity index of approximately 1.3 would provide best conformity for the authors' SRS system.

Hong, Linda X.; Garg, Madhur; Lasala, Patrick; Kim, Mimi; Mah, Dennis; Chen, Chin-Cheng; Yaparpalvi, Ravindra; Mynampati, Dinesh; Kuo, Hsiang-Chi; Guha, Chandan; Kalnicki, Shalom [Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Neurosurgery, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Epidemiology and Population Health, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

2011-03-15T23:59:59.000Z

239

Accelerator Physics and Design at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerator Science Accelerator Science ReframAccelerator.jpg Particle accelerators are among the largest, most complex, and most important scientific instruments in the world....

240

Technical Challenges and Scientific Payoffs of Muon Beam Accelerators for Particle Physics  

E-Print Network (OSTI)

particles, all of the muon beam energy is available forfootprint. Indeed, an energy frontier Muon Collider couldaccelerating muons to even higher energies of several TeV,

Zisman, Michael S.

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Feature-based Analysis of Plasma-based Particle Acceleration Data  

E-Print Network (OSTI)

traces colored by id) Feature icons with particles belongingpx x #features Feature Icon Groups/Beams Feature selection #Frame color of feature icons is used to indicate group

Ruebel, Oliver

2014-01-01T23:59:59.000Z

242

Particle Accelerators in the Hot Spots of Radio Galaxy 3C 445, Imaged with the VLT  

Science Journals Connector (OSTI)

...However, in the Kolmogorov case MHD Fermi-II–like acceleration...the plasma in HSs as seen in MHD simulations. First...the bottom to the top of the diagram, for each value of B, the Fermi-II...may power magnetohydrodynamic (MHD) turbulence that can account...

M. Almudena Prieto; Gianfranco Brunetti; Karl-Heinz Mack

2002-10-04T23:59:59.000Z

243

Induction of linear tracks of DNA double-strand breaks by -particle irradiation of  

E-Print Network (OSTI)

eukaryotic cells by exposing the cells to particles from a small Americium source (Box 1). Each particle) EQUIPMENT Americium (Am-241) source (SupplementaryMethods and SupplementaryFigs.1­3 online) Polyester film

Cai, Long

244

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

E-Print Network (OSTI)

al. , Phys. Rev. ST Accel. Beams, submitted, (2010). 15. A.D . Kimura, Phys. Rev. ST Accel. Beams 13, 24. C . Jing, A .Driven by Lasers or Particle Beams C . B . Schroeder, E .

Schroeder, C. B.

2011-01-01T23:59:59.000Z

245

Selected topics in particle accelerators: Proceedings of the CAP meetings. Volume 5  

SciTech Connect

This Report includes copies of transparencies and notes from the presentations made at the Center for Accelerator Physics at Brookhaven National Laboratory Editing and changes to the authors` contributions in this Report were made only to fulfill the publication requirements. This volume includes notes and transparencies on nine presentations: ``The Energy Exchange and Efficiency Consideration in Klystrons``, ``Some Properties of Microwave RF Sources for Future Colliders + Overview of Microwave Generation Activity at the University of Maryland``, ``Field Quality Improvements in Superconducting Magnets for RHIC``, ``Hadronic B-Physics``, ``Spiking Pulses from Free Electron Lasers: Observations and Computational Models``, ``Crystalline Beams in Circular Accelerators``, ``Accumulator Ring for AGS & Recent AGS Performance``, ``RHIC Project Machine Status``, and ``Gamma-Gamma Colliders.``

Parsa, Z. [ed.] [comp.

1995-10-01T23:59:59.000Z

246

8th ICFA Mini-Workshop on Two-Stream Instabilities in Particle Accelerators  

NLE Websites -- All DOE Office Websites (Extended Search)

Hotel Loretto Santa Fe, New Mexico, USA February 16 -18, 2000 ORGANIZING COMMITTEE WORKSHOP PROCEEDINGS HOW TO SUBMIT ELECTRONIC MANUSCRIPTS Page maintained by: cee Last updated: March 3, 2000 Disclaimer Workshop Chairs: Katherine Harkay, Argonne National Laboratory Robert Macek, Los Alamos National Laboratory Two-stream instabilities such as e-p in proton rings, ion-beam instabilities at electron accelerators, or electron cloud-induced effects observed at various accelerators can be serious limitations to the performance of high-intensity rings. This international workshop, organized by LANL and ANL, was aimed at bringing together the separate communities working on various aspects of two-stream instabilites for the purpose of sharing observations, experiences, and insights.

247

Kinetic Theories of Geodesic Acoustic Modes: Radial Structure, Linear Excitation by Energetic Particles and Nonlinear Saturation  

E-Print Network (OSTI)

Kinetic Theories of Geodesic Acoustic Modes: Radial Structure, Linear Excitation by Energetic, Vol.13, No.3, Jun 2011 Kinetic Theories of Geodesic Acoustic Modes: Radial Structure, Linear, Univ. of California, Irvine CA 92697-4575, USA Abstract Geodesic acoustic modes (GAMs) are oscillating

Zonca, Fulvio

248

Thermodynamics and higher order moments in SU(3) linear $\\sigma$-model with gluonic quasi-particles  

E-Print Network (OSTI)

In framework of linear $\\sigma$-model (LSM) with three quark flavors, the chiral phase-diagram at finite temperature and density is investigated. At temperatures higher than the critical temperature ($ T_c $), we added to LSM the gluonic sector from the quasi-particle model (QPM), which assumes that the interacting gluons in the strongly interacting matter, the quark-gluon plasma (QGP), are phenomenologically the same as non-interacting massive quasi-particles. The dependence of the chiral condensates of strange and non-strange quarks on temperature and chemical potential is analysed. Then, we have calculated the thermodynamics in the new approach (combination of LSM and QPM). Confronting the results with recent lattice QCD simulations shows an excellent agreement in almost all thermodynamic quantities. The first and second order moments of particle multiplicity are studied in dependence on the chemical potential but at fixed temperature and on the chemical potential but at fixed temperature. These are implem...

Tawfik, Abdel Nasser

2014-01-01T23:59:59.000Z

249

Heating and Non-thermal Particle Acceleration in Relativistic, Transverse Magnetosonic Shock Waves in Proton-Electron-Positron Plasmas  

E-Print Network (OSTI)

We report the results of 1D particle-in-cell simulations of ultrarelativistic shock waves in proton-electron-positron plasmas. We consider magnetized shock waves, in which the upstream medium carries a large scale magnetic field, directed transverse to the flow. Relativistic cyclotron instability of each species as the incoming particles encounter the increasing magnetic field within the shock front provides the basic plasma heating mechanism. The most significant new results come from simulations with mass ratio $m_p/m_\\pm = 100$. We show that if the protons provide a sufficiently large fraction of the upstream flow energy density (including particle kinetic energy and Poynting flux), a substantial fraction of the shock heating goes into the formation of suprathermal power-law spectra of pairs. Cyclotron absorption by the pairs of the high harmonic ion cyclotron waves, emitted by the protons, provides the non-thermal acceleration mechanism. As the proton fraction increases, the non-thermal efficiency increases and the pairs' power-law spectra harden. We suggest that the varying power law spectra observed in synchrotron sources powered by magnetized winds and jets might reflect the correlation of the proton to pair content enforced by the underlying electrodynamics of these sources' outflows, and that the observed correlation between the X-ray spectra of rotation powered pulsars with the X-ray spectra of their nebulae might reflect the same correlation.

Elena Amato; Jonathan Arons

2006-09-01T23:59:59.000Z

250

Improvements in dose accuracy delivered with static-MLC IMRT on an integrated linear accelerator control system  

SciTech Connect

Purpose: Dose accuracy has been shown to vary with dose per segment and dose rate when delivered with static multileaf collimator (SMLC) intensity modulated radiation therapy (IMRT) by Varian C-series MLC controllers. The authors investigated the impact of monitor units (MUs) per segment and dose rate on the dose delivery accuracy of SMLC-IMRT fields on a Varian TrueBeam linear accelerator (LINAC), which delivers dose and manages motion of all components using a single integrated controller. Methods: An SMLC sequence was created consisting of ten identical 10 x 10 cm{sup 2} segments with identical MUs. Beam holding between segments was achieved by moving one out-of-field MLC leaf pair. Measurements were repeated for various combinations of MU/segment ranging from 1 to 40 and dose rates of 100-600 MU/min for a 6 MV photon beam (6X) and dose rates of 800-2400 MU/min for a 10 MV flattening-filter free photon (10XFFF) beam. All measurements were made with a Farmer (0.6 cm{sup 3}) ionization chamber placed at the isocenter in a solid-water phantom at 10 cm depth. The measurements were performed on two Varian LINACs: C-series Trilogy and TrueBeam. Each sequence was delivered three times and the dose readings for the corresponding segments were averaged. The effects of MU/segment, dose rate, and LINAC type on the relative dose variation ({Delta}{sub i}) were compared using F-tests ({alpha} = 0.05). Results: On the Trilogy, large {Delta}{sub i} was observed in small MU segments: at 1 MU/segment, the maximum {Delta}{sub i} was 10.1% and 57.9% at 100 MU/min and 600 MU/min, respectively. Also, the first segment of each sequence consistently overshot ({Delta}{sub i} > 0), while the last segment consistently undershot ({Delta}{sub i} < 0). On the TrueBeam, at 1 MU/segment, {Delta}{sub i} ranged from 3.0% to 4.5% at 100 and 600 MU/min; no obvious overshoot/undershoot trend was observed. F-tests showed statistically significant difference [(1 - {beta}) =1.0000] between the Trilogy and the TrueBeam up to 10 MU/segment, at all dose rates greater than 100 MU/min. The linear trend of decreasing dose accuracy as a function of increasing dose rate on the Trilogy is no longer apparent on TrueBeam, even for dose rates as high as 2400 MU/min. Dose inaccuracy averaged over all ten segments in each beam delivery sequence was larger for Trilogy than TrueBeam, with the largest discrepancy (0.2% vs 3%) occurring for 1 MU/segment beams at both 300 and 600 MU/min. Conclusions: Earlier generations of Varian LINACs exhibited large dose variations for small MU segments in SMLC-IMRT delivery. Our results confirmed these findings. The dose delivery accuracy for SMLC-IMRT is significantly improved on TrueBeam compared to Trilogy for every combination of low MU/segment (1-10) and high dose rate (200-600 MU/min), in part due to the faster sampling rate (100 vs 20 Hz) and enhanced electronic integration of the MLC controller with the LINAC. SMLC-IMRT can be implemented on TrueBeam with higher dose accuracy per beam ({+-}0.2% vs {+-}3%) than previous generations of Varian C-series LINACs for 1 MU/segment delivered at 600 MU/min).

Li Ji; Wiersma, Rodney D.; Stepaniak, Christopher J.; Farrey, Karl J.; Al-Hallaq, Hania A. [Department of Radiation and Cellular Oncology, University of Chicago, 5758 South Maryland Avenue, MC9006, Chicago, Illinois 60637 (United States)

2012-05-15T23:59:59.000Z

251

Diffusive Acceleration of Ions at Interplanetary Shocks  

E-Print Network (OSTI)

Heliospheric shocks are excellent systems for testing theories of particle acceleration in their environs. These generally fall into two classes: (1) interplanetary shocks that are linear in their ion acceleration characteristics, with the non-thermal ions serving as test particles, and (2) non-linear systems such as the Earth's bow shock and the solar wind termination shock, where the accelerated ions strongly influence the magnetohydrodynamic structure of the shock. This paper explores the modelling of diffusive acceleration at a particular interplanetary shock, with an emphasis on explaining in situ measurements of ion distribution functions. The observational data for this event was acquired on day 292 of 1991 by the Ulysses mission. The modeling is performed using a well-known kinetic Monte Carlo simulation, which has yielded good agreement with observations at several heliospheric shocks, as have other theoretical techniques, namely hybrid plasma simulations, and numerical solution of the diffusion-conv...

Baring, M G; Baring, Matthew G.; Summerlin, Errol J.

2005-01-01T23:59:59.000Z

252

Beam-Induced Multipactoring and Electron-Cloud Effects in Particle Accelerators  

E-Print Network (OSTI)

In the beam pipe of high-energy proton or positron accelerators an “electron cloud” can be generated by a variety of processes, e.g. by residual-gas ionization, by photoemission from synchrotron radiation, and, most importantly, by secondary emission via a beam-induced multipactoring process. The electron cloud commonly leads to a degradation of the beam vacuum by several orders of magnitude, to fast beam instabilities, to beam-size increases, and to fast or slow beam losses. At the Large Hadron Collider (LHC), the cloud electrons could also give rise to an additional heat load inside cold superconducting magnets. In addition to the direct heat deposition from incoherently moving electrons, a potential “magnetron effect” has been conjectured, where electrons would radiate coherently when moving in a strong magnetic field under the simultaneous influence of a beam-induced electric “wake” field that may become resonant with the cyclotron frequency. Electron-cloud effects are already being observed w...

Caspers, Friedhelm; Scandale, Walter; Zimmermann, F

2009-01-01T23:59:59.000Z

253

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

E-Print Network (OSTI)

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

2013-01-01T23:59:59.000Z

254

Acceleration of low energy nuclear reactions by formation of correlated states of interacting particles in dynamical systems  

Science Journals Connector (OSTI)

Abstract In this work the most universal mechanism of essential acceleration of low energy nuclear reactions on the basis of correlated states of interacting particles is considered. This mechanism provides a giant increase of barrier penetrability under critical conditions (low energy, high barrier), where the effectiveness of “ordinary” tunneling effects is negligibly small, and can be applied to different experiments. The physical reason of an increased barrier penetrability in correlated states is connected to the modified uncertainty relation ? p ? q ? ? 2 / 4 1 - r pq 2 for correlated states and to the increase in momentum ?p and position ?q variances with increasing of correlation coefficient rpq. We have considered preconditions and methods of formation of correlated coherent states of interacting nuclei in non-stationary dynamical systems. It was shown that in real nuclear-physical systems at r pq 2 ? 1 very sharp growth (up to a factor of 1030–10100 and more!) of Coulomb barrier penetrability at very low energy of interacting particles is possible. Several successful low-energy correlated-induced fusion experiments are discussed.

Vladimir I. Vysotskii; Stanislav V. Adamenko; Mykhaylo V. Vysotskyy

2013-01-01T23:59:59.000Z

255

Interactive visual intervention planning in particle accelerator environments with ionizing radiation  

E-Print Network (OSTI)

Radiation is omnipresent. It has many interesting applications: in medicine, where it allows curing and diagnosing patients; in communication, where modern communication systems make use of electromagnetic radiation; and in science, where it is used to discover the structure of materials; to name a few. Physically, radiation is a process in which particles or waves travel through any kind of material, usually air. Radiation can be very energetic, in which case it can break the atoms of ordinary matter (ionization). If this is the case, radiation is called ionizing. It is known that ionizing radiation can be far more harmful to living beings than non-ionizing radiation. In this dissertation, we are concerned with ionizing radiation. Naturally occurring ionizing radiation in the form of radioactivity is a most natural phenomenon. Almost everything is radioactive: there is radiation emerging from the soil, it is in the air, and the whole planet is constantly undergoing streams of energetic cosmic radiation. Sinc...

Fabry, Thomas

256

Preliminary design report of a relativistic-Klystron two-beam-accelerator based power source for a 1 TeV center-of-mass next linear collider  

SciTech Connect

A preliminary point design for an 11.4 GHz power source for a 1 TeV center-of-mass Next Linear Collider (NLC) based on the Relativistic-Klystron Two-Beam-Accelerator (RK-TBA) concept is presented. The present report is the result of a joint LBL-LLNL systems study. consisting of three major thrust areas: physics, engineering, and costing. The new RK-TBA point design, together with our findings in each of these areas, are reported.

Yu, S.; Goffeney, N.; Henestroza, E. [Lawrence Berkeley Lab., CA (United States)] [and others

1995-02-22T23:59:59.000Z

257

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

E-Print Network (OSTI)

the 1989 Particle Accelerator Conference (IEEE, Piscataway,the 1993 Particle Accelerator Conference (IEEE, Piscataway,Diagnostics for Laser Plasma Accelerators K. Nakamura, 1 A.

Nakamura, Kei

2012-01-01T23:59:59.000Z

258

Diffusive Acceleration of Ions at Interplanetary Shocks  

Science Journals Connector (OSTI)

Heliospheric shocks are excellent systems for testing theories of particle acceleration in their environs. These generally fall into two classes: (1) interplanetary shocks that are linear in their ion acceleration characteristics with the non?thermal ions serving as test particles and (2) non?linear systems such as the Earth’s bow shock and the solar wind termination shock where the accelerated ions strongly influence the magnetohydrodynamic structure of the shock. This paper explores the modelling of diffusive acceleration at a particular interplanetary shock with an emphasis on explaining in situ measurements of ion distribution functions. The observational data for this event was acquired on day 292 of 1991 by the Ulysses mission. The modeling is performed using a well?known kinetic Monte Carlo simulation which has yielded good agreement with observations at several heliospheric shocks as have other theoretical techniques namely hybrid plasma simulations and numerical solution of the diffusion?convection equation. In this theory/data comparison it is demonstrated that diffusive acceleration theory can to first order successfully account for both the proton distribution data near the shock and the observation of energetic protons farther upstream of this interplanetary shock than lower energy pick?up protons using a single turbulence parameter. The principal conclusion is that diffusive acceleration of inflowing upstream ions can model this pick?up ion?rich event without the invoking any seed pre?acceleration mechanism though this investigation does not rule out the action of such pre?acceleration.

Matthew G. Baring; Errol J. Summerlin

2005-01-01T23:59:59.000Z

259

Diffusive Acceleration of Ions at Interplanetary Shocks  

E-Print Network (OSTI)

Heliospheric shocks are excellent systems for testing theories of particle acceleration in their environs. These generally fall into two classes: (1) interplanetary shocks that are linear in their ion acceleration characteristics, with the non-thermal ions serving as test particles, and (2) non-linear systems such as the Earth's bow shock and the solar wind termination shock, where the accelerated ions strongly influence the magnetohydrodynamic structure of the shock. This paper explores the modelling of diffusive acceleration at a particular interplanetary shock, with an emphasis on explaining in situ measurements of ion distribution functions. The observational data for this event was acquired on day 292 of 1991 by the Ulysses mission. The modeling is performed using a well-known kinetic Monte Carlo simulation, which has yielded good agreement with observations at several heliospheric shocks, as have other theoretical techniques, namely hybrid plasma simulations, and numerical solution of the diffusion-convection equation. In this theory/data comparison, it is demonstrated that diffusive acceleration theory can, to first order, successfully account for both the proton distribution data near the shock, and the observation of energetic protons farther upstream of this interplanetary shock than lower energy pick-up protons, using a single turbulence parameter. The principal conclusion is that diffusive acceleration of inflowing upstream ions can model this pick-up ion-rich event without the invoking any seed pre-acceleration mechanism, though this investigation does not rule out the action of such pre-acceleration.

Matthew G. Baring; Errol J. Summerlin

2005-06-08T23:59:59.000Z

260

Charge Diagnostics for Laser Plasma Accelerators  

E-Print Network (OSTI)

the 1989 Particle Accelerator Conference, IEEE, Piscataway,Diagnostics for Laser Plasma Accelerators K . Nakamura, A .ALS) synchrotron booster accelerator. The sensitivity of the

Nakamura, K.

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Linear and nonlinear dynamics of a dust bicrystal consisting of positive and negative dust particles  

SciTech Connect

A dusty plasma crystalline configuration consisting of charged dust grains of alternating charge sign ({center_dot}{center_dot}{center_dot}/+/-/+/-/+/{center_dot}{center_dot}{center_dot}) and mass is considered. Both charge and mass of each dust species are taken to be constant. Considering the equations of longitudinal motion, a dispersion relation for linear longitudinal vibrations is derived from first principles and then analyzed. Two harmonic modes are obtained, namely, an acoustic mode and an inverse-dispersive optic-like one. The nonlinear aspects of acoustic longitudinal dust grain motion are addressed via a generalized Boussinesq (and, alternatively, a generalized Korteweg-de Vries) description.

Kourakis, I.; Shukla, P.K.; Morfill, G.E. [Institut fuer Theoretische Physik IV and Centre for Plasma Science and Astrophysics, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Max-Planck Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85740 Garching (Germany)

2005-11-15T23:59:59.000Z

262

European Particle Accelerator Conference -Rome, Italy -June 7-12, 1988 DEVELOPMENT OFA HIGH BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT  

E-Print Network (OSTI)

BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT BROOKHAVEN NATIONAL LABORATORY* K. Batchelor, HDonald Princeton University At innBNL--41767 DE89 002179 Abstract An electron gun utilizing aradio frequency on the design of (he electron gun which will provide r.f. bunches of upto 101 electrons synchronized

McDonald, Kirk

263

Fermilab | Tevatron | Accelerator  

NLE Websites -- All DOE Office Websites (Extended Search)

particle accelerator in the world before it shut down on Sept. 29, 2011. It accelerated beams of protons and antiprotons to 99.999954 percent of the speed of light around a...

264

Argonne Accelerator Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

AAI Home AAI Home Welcome Accelerators at Argonne Mission Organization History Document Collection Conferences & Workshops Beams and Applications Seminar Argonne-Fermilab Collaboration Lee Teng Scholarship Program Useful Links Argonne Accelerator Institute In 2006, Argonne Laboratory Director Robert Rosner formed the AAI as a focal point for accelerator initiatives. The institute works to utilize Argonne's extensive accelerator resources, to enhance existing facilities, to determine the future of accelerator development and construction, and to oversee a dynamic and acclaimed accelerator physics portfolio. More Information for: Members * Students Industrial Collaborators - Working with Argonne Link to: Accelerators for America's Future Upcoming Events and News 4th International Particle Accelerator Conference (IPAC'13)

265

Ion Pre-acceleration in Fully Self-consistent Particle-in-cell Simulations of Supercritical Perpendicular Reforming Shocks in Multiple Ion Species Plasmas  

Science Journals Connector (OSTI)

Supernova remnant and heliopause termination shock plasmas may contain significant populations of minority heavy ions, with relative number densities n ?/ni up to 50%. Preliminary kinetic simulations of collisionless shocks in these environments showed that the reformation cycle and acceleration mechanisms at quasi-perpendicular shocks can depend on the value of n ?/ni . Shock reformation unfolds on ion spatio-temporal scales, requiring fully kinetic simulations of particle dynamics, together with the self-consistent electric and magnetic fields. This paper presents the first set of particle-in-cell simulations for two ion species, protons (np ) and ?-particles (n ?), with differing mass and charge-to-mass ratios, that spans the entire range of n ?/ni from 0% to 100%. The interplay between the differing gyro length scales and timescales of the ion species is crucial to the time-evolving phenomenology of the shocks, the downstream turbulence, and the particle acceleration at different n ?/ni . We show how the overall energization changes with n ?/ni , and relate this to the processes individual ions undergo in the shock region and in the downstream turbulence, and to the power spectra of magnetic field fluctuations. The crossover between shocks dominated by the respective ion species happens when n ?/ni = 25%, and minority ion energization is strongest in this regime. Energization of the majority ion species scales with injection energy. The power spectrum of the downstream turbulence includes peaks at sequential ion cyclotron harmonics, suggestive of ion ring-beam collective instability.

V. L. Rekaa; S. C. Chapman; R. O. Dendy

2014-01-01T23:59:59.000Z

266

Derivation of Hamiltonians for accelerators  

SciTech Connect

In this report various forms of the Hamiltonian for particle motion in an accelerator will be derived. Except where noted, the treatment will apply generally to linear and circular accelerators, storage rings, and beamlines. The generic term accelerator will be used to refer to any of these devices. The author will use the usual accelerator coordinate system, which will be introduced first, along with a list of handy formulas. He then starts from the general Hamiltonian for a particle in an electromagnetic field, using the accelerator coordinate system, with time t as independent variable. He switches to a form more convenient for most purposes using the distance s along the reference orbit as independent variable. In section 2, formulas will be derived for the vector potentials that describe the various lattice components. In sections 3, 4, and 5, special forms of the Hamiltonian will be derived for transverse horizontal and vertical motion, for longitudinal motion, and for synchrobetatron coupling of horizontal and longitudinal motions. Hamiltonians will be expanded to fourth order in the variables.

Symon, K.R.

1997-09-12T23:59:59.000Z

267

Effects of Hyperbolic Rotation in Minkowski Space on the Modeling of Plasma Accelerators in a Lorentz Boosted Frame  

E-Print Network (OSTI)

al. , in Proc. Particle Accelerator Conference ( Vancouver,al. , in Proc. Particle Accelerator Conference (Vancouver,al. , in Proc. Particle Accelerator Con- ference (Vancouver,

Vay, J.-L.

2010-01-01T23:59:59.000Z

268

E-Print Network 3.0 - accelerator mass spectrometry Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

accelerator mass... ATLAS Argonne Tandem Linear Accelerator System The prime national facility for nuclear structure... , accelerated in the world's first superconducting linear...

269

Fermilab | Science | Particle Physics | Benefits of Particle...  

NLE Websites -- All DOE Office Websites (Extended Search)

Benefits of Particle Physics photo Each generation of particle accelerators and detectors builds on the previous one, raising the potential for discovery and pushing the level of...

270

LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS  

E-Print Network (OSTI)

LASER-PLASMA-ACCELERATOR-BASED ?? COLLIDERS ? C. B.linear col- lider based on laser-plasma-accelerators arediscussed, and a laser-plasma-accelerator-based gamma-

Schroeder, C. B.

2010-01-01T23:59:59.000Z

271

Accelerator-Based Irradiation Creep of Pyrolytic Carbon Used in TRISO Fuel Particles for the (VHTR) Very Hight Temperature Reactors  

SciTech Connect

Pyrolytic carbon (PyC) is one of the important structural materials in the TRISO fuel particles which will be used in the next generation of gas-cooled very-high-temperature reactors (VHTR). When the TRISO particles are under irradiation at high temperatures, creep of the PyC layers may cause radial cracking leading to catastrophic particle failure. Therefore, a fundamental understanding of the creep behavior of PyC during irradiation is required to predict the overall fuel performance.

Lumin Wang; Gary Was

2010-07-30T23:59:59.000Z

272

Shielding of proton accelerators  

Science Journals Connector (OSTI)

......capabilities of an accelerator control system...meant to undergo a nuclear interaction within...the axis of the vacuum chamber. The beam...of high-energy accelerators. Nucl. Instrum...Series, Group I: Nuclear and Particle Physics-Schopper...100-250 MeV proton accelerators: double differential......

Stefano Agosteo; Matteo Magistris; Marco Silari

2011-07-01T23:59:59.000Z

273

1. Blandford, R. Particle acceleration at astrophysical shocks: A theory of cosmic ray origin [Text] / R. Blandford,  

E-Print Network (OSTI)

-wavelength mode instability [Text] / A.M. Bykov, S.M. Osipov, D.C. Ellison // Monthly Notices Royal Astronomical Society. ­ 2011. ­ Vol. 410. ­ P. 39­52. 4. Shapiro, V.D. Non-resonant firehose instability: Consequences for the theory of cosmic ray acceleration [Text] / V.D. Shapiro, K.B. Quest, M. Okolicsanyi

274

Staging laser plasma accelerators for increased beam energy  

E-Print Network (OSTI)

Staging Laser Plasma Accelerators for Increased Beam EnergyStaging laser plasma accelerators is an efficient way ofcompact laser-plasma accelerators to generate particle

Panasenko, Dmitriy

2010-01-01T23:59:59.000Z

275

Accelerators: powering cutting-edge research  

E-Print Network (OSTI)

Accelerators: powering cutting-edge research #12;What is a particle accelerator? Booster ourselves. Particle accelerators are our attempt to turn back the clock and see into the early stages of the Universe. They accelerate everyday charged particles (electrons or protons) to close to the speed of light

Crowther, Paul

276

Magneto-optical granulometry: on the determination of the statistics of magnetically induced particle chains in concentrated ferrofluids from linear dichroism experiments  

E-Print Network (OSTI)

An analytical theoretical model for the influence of the magnetically induced nanoparticle chaining on the linear dichroism in ferrofluids was developed. The model is based on a statistical theory for magnetic nanoparticle chaining in ferrofluids. Together with appropriate experimental approach and data processing strategy, the model grounds a magneto-optical granulometry method able to determine the magnetic field dependence of the statistics of magnetically induced particle chains in concentrated ferrofluids.

V. Socoliuc; L. B. Popescu

2014-10-09T23:59:59.000Z

277

About Us: Accelerator Operations and Technology, AOT: LANL  

NLE Websites -- All DOE Office Websites (Extended Search)

About AOT Accelerator and Operations Technology AOT Division provides operations and related support for the Los Alamos Neutron Science Center (LANSCE), conducting fundamental and applied research and development needed to improve its operations support efforts. AOT's R&D efforts include plasma physics, ion beam generation; accelerator physics; linear-accelerator-structure engineering, design; high-space-charge proton-accumulator/compressor-ring physics; beam-transport-lattice physics, engineering; particle-beam-diagnostics physics, engineering; high- and low-power-radio-frequency-system engineering; high-voltage and -current, pulsed-power engineering; magnet-power-system engineering; mechanical engineering, design (e.g., precision alignment technology);

278

Measurement of electron clouds in large accelerators by microwave dispersion  

SciTech Connect

Clouds of low energy electrons in the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation at high currents. Furthermore, it is difficult to probe their density over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave transmitted over a section of the accelerator and used it to measure the average electron cloud density over a 50 m section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center.

Desantis, Stefano; De Santis, Stefano; Byrd, John M.; Sonnad, Kiran G.; Pivi, Mauro T.F.; Krasnykh, Anatoly; Caspers, Fritz; Kroyer, Tom

2008-01-24T23:59:59.000Z

279

Particle Physics Booklet 2008  

E-Print Network (OSTI)

212 25. Accelerator physics of colliders ? 26. High-energythe full Review. PARTICLE PHYSICS BOOKLET TABLE OF CONTENTSrev. ) Summary Tables of Particle Physics Gauge and Higgs

et al., C. Amsler

2008-01-01T23:59:59.000Z

280

Future Accelerators, Muon Colliders, and Neutrino Factories  

SciTech Connect

Particle physics is driven by five great topics. Neutrino oscillations and masses are now at the fore. The standard model with extensions to supersymmetry and a Higgs to generate mass explains much of the field. The origins of CP violation are not understood. The possibility of extra dimensions has raised tantalizing new questions. A fifth topic lurking in the background is the possibility of something totally different. Many of the questions raised by these topics require powerful new accelerators. It is not an overstatement to say that for some of the issues, the accelerator is almost the experiment. Indeed some of the questions require machines beyond our present capability. As this volume attests, there are parts of the particle physics program that have been significantly advanced without the use of accelerators such as the subject of neutrino oscillations and many aspects of the particle-cosmology interface. At this stage in the development of physics, both approaches are needed and important. This chapter first reviews the status of the great accelerator facilities now in operation or coming on within the decade. Next, midrange possibilities are discussed including linear colliders with the adjunct possibility of gamma-gamma colliders, muon colliders, with precursor neutrino factories, and very large hadron colliders. Finally visionary possibilities are considered including plasma and laser accelerators.

Richard A Carrigan, Jr.

2001-12-19T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

The evolution of high energy accelerators  

SciTech Connect

Accelerators have been devised and built for two reasons: In the first place, by physicists who needed high energy particles in order to have a means to explore the interactions between particles that probe the fundamental elementary forces of nature. And conversely, sometimes accelerator builders produce new machines for higher energy than ever before just because it can be done, and then challenge potential users to make new discoveries with the new means at hand. These two approaches or motivations have gone hand in hand. This lecture traces how high energy particle accelerators have grown from tools used for esoteric small-scale experiments to the gigantic projects of today. So far all the really high-energy machines built and planned in the world--except the SLC--have been ring accelerators and storage rings using the strong-focusing method. But this method has not removed the energy limit, it has only pushed it higher. It would seem unlikely that one can go beyond the Large Hadron Collider (LHC)--but in fact a workshop was held in Sicily in November 1991, concerned with the question of extrapolating to 100 TeV. Other acceleration and beam-forming methods are now being discussed--collective fields, laser acceleration, wake-field accelerators etc., all aimed primarily at making linear colliders possible and more attractive than with present radiofrequency methods. So far it is not entirely clear which of these schemes will dominate particle physics in the future--maybe something that has not been thought of as yet.

Courant, E.D.

1994-08-01T23:59:59.000Z

282

Challenges in future linear colliders  

SciTech Connect

For decades, electron-positron colliders have been complementing proton-proton colliders. But the circular LEP, the largest e-e+ collider, represented an energy limit beyond which energy losses to synchrotron radiation necessitate moving to e-e+ linear colliders (LCs), thereby raising new challenges for accelerator builders. Japanese-American, German, and European collaborations have presented options for the Future Linear Collider (FLC). Key accelerator issues for any FLC option are the achievement of high enough energy and luminosity. Damping rings, taking advantage of the phenomenon of synchrotron radiation, have been developed as the means for decreasing beam size, which is crucial for ensuring a sufficiently high rate of particle-particle collisions. Related challenges are alignment and stability in an environment where even minute ground motion can disrupt performance, and the ability to monitor beam size. The technical challenges exist within a wider context of socioeconomic and political challenges, likely necessitating continued development of international collaboration among parties involved in accelerator-based physics.

Swapan Chattopadhyay; Kaoru Yokoya

2002-09-02T23:59:59.000Z

283

Accelerators and the Accelerator Community  

E-Print Network (OSTI)

of electrostatic accelerators, while Ernest O. Lawrence (CBP 820 LBNL TBA ACCELERATORS ANDTHE ACCELERATOR COMMUNITY 1 ANDREW SESSLER Lawrence Berkeley

Malamud, Ernest

2009-01-01T23:59:59.000Z

284

accelerators for ATI  

NLE Websites -- All DOE Office Websites (Extended Search)

Building Accelerator Analogs Building Accelerator Analogs Some QuarkNet centers have built "accelerators." No, they are not real but can be used as analogs to real particle accelerators. The real learning comes, of course, when you plan and experiment on your own, but this may give you some starting points. Things to Think About What are your objectives? To make an analogy for particle accelerators? To use classical physics qualitatively? To use classical physics quantitatively? To measure forces, speed, etc.? _______________ Who is your target audience— in an Associate Teacher Institute or their students or both? What do the participants need to know before beginning? Jawbreaker Accelerator Pressurized gas shoots jawbreakers through PVC pipe into a fixed target (brick) or into each other. The original speeds and masses are measured as are those of the resulting particles.

285

Finding of No Significant Impact for the Construction and Operation of the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center (SLAC), California (DOE/EA-1426) (2/28/03)  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

U.S. Department of Energy (DOE) U.S. Department of Energy (DOE) Finding of No Significant Impact Construction and Operation of the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center (SLAC), California. AGENCY: U.S. Department of Energy (DOE) ACTION: Finding of No Significant Impact (FONSI) SUMMARY: The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA), DOE/EA-1426, evaluating the proposed action to construct and operate the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center (SLAC). Based upon the information and analyses in the EA, the DOE has determined that the proposed federal action does not significantly affect the quality of the human environment within the meaning of the National Environmental Policy Act of 1969.

286

Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators  

DOE Patents (OSTI)

A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 12 figs.

Caporaso, G.J.; Sampayan, S.E.; Kirbie, H.C.

1998-10-13T23:59:59.000Z

287

Accelerators, Electrodynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Science and Innovation Capabilities Accelerators, Electrodynamics science-innovationassetsimagesicon-science.jpg Accelerators, Electrodynamics National security depends...

288

Engineering Prototype for a Compact Medical Dielectric Wall Accelerator  

Science Journals Connector (OSTI)

A compact accelerator system architecture based on the dielectric wall accelerator (DWA) for medical proton beam therapy has been developed by the Compact Particle Acceleration Corporation (CPAC). The major subsystems are a Radio Frequency Quadrupole (RFQ) injector linac a pulsed kicker to select the desired proton bunches and a DWA linear accelerator incorporating a high gradient insulator (HGI) with stacked Blumleins to produce the required acceleration energy. The Blumleins are switched with solid state laser?driven optical switches integrated into the Blumlein assemblies. Other subsystems include a high power pulsed laser fiber optic distribution system electrical charging system and beam diagnostics. An engineering prototype has been constructed and characterized and these results will be used within the next three years to develop an extremely compact 150 MeV system capable of modulating energy beam current and spot size on a shot?to?shot basis. This paper presents the details the engineering prototype experimental results and commercialization plans.

Anthony Zografos; Andy Hening; Vladimir Joshkin; Kevin Leung; Dave Pearson; Henry Pearce?Percy; Mario Rougieri; Yoko Parker; John Weir; Donald Blackfield; Yu?Jiuan Chen; Steven Falabella; Gary Guethlein; Brian Poole; Robert W. Hamm; Reinard Becker

2011-01-01T23:59:59.000Z

289

RHIC | Accelerator Complex  

NLE Websites -- All DOE Office Websites (Extended Search)

RHIC Accelerators RHIC Accelerators The Relativistic Heavy Ion Collider complex is actually composed of a long "chain" of particle accelerators Heavy ions begin their travels in the Electron Beam Ion Source accelerator (1). The ions then travel to the small, circular Booster (3) where, with each pass, they are accelerated to higher energy. From the Booster, ions travel to the Alternating Gradient Synchrotron (4), which then injects the beams via a beamline (5) into the two rings of RHIC (6). In RHIC, the beams get a final accelerator "kick up" in energy from radio waves. Once accelerated, the ions can "orbit" inside the rings for hours. RHIC can also conduct colliding-beam experiments with polarized protons. These are first accelerated in the Linac (2), and further in the Booster (3), AGS (4), and

290

Argonne Accelerator Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

AAI Homepage Lee Teng Scholarship Program USPAS Argonne Department of Education Fermilab Education Office For Students Many scientific advances are made using accelerators. The world of High Energy Particle Physics has driven this field and continues to depend largely on accelerators. Increasingly advances in materials science, chemistry, biology and environmental science are being made at accelerators using x-ray and neutrons to probe matter. Accelerators have a number of commercial applications including isotope production for use in medicine, cancer treatment, processing semiconductor chips, and so on. Presently there are around 15,000 accelerators worldwide. Approximately 97% of these are used for commercial applications. However several hundred are in use

291

Particle-in-cell simulation studies of the non-linear evolution of ultrarelativistic two-stream instabilities  

Science Journals Connector (OSTI)

......from inverse Compton scattering or thermal emissions (Ryde 2004, 2005) or...relativistic beams, such as those in Thode Sudan (1973). Colliding e + e beams have...growth in cold homogeneous plasma from thermal noise levels to non-linear saturation......

M. E. Dieckmann; P. K. Shukla; L. O. C. Drury

2006-04-11T23:59:59.000Z

292

Challenges in Accelerator Beam Instrumentation  

SciTech Connect

The challenges in beam instrumentation and diagnostics for present and future particle accelerator projects are presented. A few examples for advanced hadron and lepton beam diagnostics are given.

Wendt, M.

2009-12-01T23:59:59.000Z

293

Accelerator on a Chip  

ScienceCinema (OSTI)

SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

England, Joel

2014-07-16T23:59:59.000Z

294

Accelerator on a Chip  

SciTech Connect

SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

England, Joel

2014-06-30T23:59:59.000Z

295

Miniaturization Techniques for Accelerators  

SciTech Connect

The possibility of laser driven accelerators [1] suggests the need for new structures based on micromachining and integrated circuit technology because of the comparable scales. Thus, we are exploring fully integrated structures including sources, optics (for both light and particle) and acceleration in a common format--an accelerator-on-chip (AOC). Tests suggest a number of preferred materials and techniques but no technical or fundamental roadblocks at scales of order 1 {micro}m or larger.

Spencer, James E.

2003-05-27T23:59:59.000Z

296

Experimental Particle Physics  

SciTech Connect

The high energy physics group at the University of South Carolina, under the leadership of Profs. S.R. Mishra, R. Petti, M.V. Purohit, J.R. Wilson (co-PI's), and C. Rosenfeld (PI), engaged in studies in "Experimental Particle Physics." The group collaborated with similar groups at other universities and at national laboratories to conduct experimental studies of elementary particle properties. We utilized the particle accelerators at the Fermi National Accelerator Laboratory (Fermilab) in Illinois, the Stanford Linear Accelerator Center (SLAC) in California, and the European Center for Nuclear Research (CERN) in Switzerland. Mishra, Rosenfeld, and Petti worked predominantly on neutrino experiments. Experiments conducted in the last fifteen years that used cosmic rays and the core of the sun as a source of neutrinos showed conclusively that, contrary to the former conventional wisdom, the "flavor" of a neutrino is not immutable. A neutrino of flavor "e," "mu," or "tau," as determined from its provenance, may swap its identity with one of the other flavors -- in our jargon, they "oscillate." The oscillation phenomenon is extraordinarily difficult to study because neutrino interactions with our instruments are exceedingly rare -- they travel through the earth mostly unimpeded -- and because they must travel great distances before a substantial proportion have made the identity swap. Three of the experiments that we worked on, MINOS, NOvA, and LBNE utilize a beam of neutrinos from an accelerator at Fermilab to determine the parameters governing the oscillation. Two other experiments that we worked on, NOMAD and MIPP, provide measurements supportive of the oscillation experiments. Good measurements of the neutrino oscillation parameters may constitute a "low energy window" on related phenomena that are otherwise unobservable because they would occur only at energies way above the reach of conceivable accelerators. Purohit and Wilson participated in the BaBar experiment, which collected data at SLAC until 2008. They continued to analyze the voluminous BaBar data with an emphasis on precision tests of Quantum Chromodynamics and on properties of the "eta_B," a bottom quark paired in a meson with a strange quark. The ATLAS experiment became the principal research focus for Purohit. One of the world's largest pieces of scientific equipment, ATLAS observes particle collisions at the highest-energy particle accelerator ever built, the Large Hadron Collider (LHC) at CERN. Our efforts on ATLAS included participation in the commissioning, calibration, and installation of components called "CSCs". The unprecedented energy of 14 TeV enabled the ATLAS and CMS collaborations to declare discovery of the famous Higgs particle in 2012.

Rosenfeld, Carl [Univ of South Carolina] (ORCID:0000000338571223); Mishra, Sanjib R. [Univ of South Carolina; Petti, Roberto [Univ of South Carolina; Purohit, Milind V. [Univ of South Carolina

2014-08-31T23:59:59.000Z

297

Breakthrough: Fermilab Accelerator Technology  

SciTech Connect

There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

None

2012-04-23T23:59:59.000Z

298

Breakthrough: Fermilab Accelerator Technology  

ScienceCinema (OSTI)

There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

None

2014-08-12T23:59:59.000Z

299

E-Print Network 3.0 - accelerator electron radiotherapy Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Continuous Electron Beam Accelerator Facility, Newport News, Virginia (the Big... & Phenomenology Particle Astrophysics & Cosmology Accelerator Physics Health Physics...

300

E-Print Network 3.0 - accelerator facility jefferson Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Continuous Electron Beam Accelerator Facility, Newport News, Virginia (the Big... & Phenomenology Particle Astrophysics & Cosmology Accelerator Physics Health Physics...

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Some remarks on the quasilinear treatment of the stochastic acceleration problem  

E-Print Network (OSTI)

-standard ``diffusive'' behaviors i.e., such that the mean square displacement of a test particle does not grow linearly with zero mean and with the following second-order correlation: C x,t E x x ,t t E x ,t . 2 One also assumes of the stochastic acceleration problem, the meaning of the theory. Indeed, in recent publications,3

Van Den Eijnden, Eric

302

Primer on Detectors and Electronics for Particle Physics Experiments  

E-Print Network (OSTI)

1 Primer on Detectors and Electronics for Particle Physics Experiments Alexander A. Grillo Santa, cyclotrons, synchrotrons, and linear accelerators. The projectiles of choice were electrons and protons of detectors used in scattering experiments and the electronics required to make them work. The different

California at Santa Cruz, University of

303

The Next Linear Collider: NLC2001  

SciTech Connect

Recent studies in elementary particle physics have made the need for an e{sup +}e{sup -} linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever [1]. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider. A first Zeroth-Order Design Report (ZDR) [2] for a second-generation electron-positron linear collider, the Next Linear Collider (NLC), was published five years ago. The NLC design is based on a high-frequency room-temperature rf accelerator. Its goal is exploration of elementary particle physics at the TeV center-of-mass energy, while learning how to design and build colliders at still higher energies. Many advances in accelerator technologies and improvements in the design of the NLC have been made since 1996. This Report is a brief update of the ZDR.

D. Burke et al.

2002-01-14T23:59:59.000Z

304

3-D particle-in-cell simulations for quasi-phase matched direct laser electron acceleration in density-modulated plasma waveguides  

E-Print Network (OSTI)

Quasi-phase matched direct laser acceleration (DLA) of electrons can be realized with guided, radially polarized laser pulses in density-modulated plasma waveguides. A 3-D particle-in-cell model has been developed to describe the interactions among the laser field, injected electrons, and the background plasma in the DLA process. Simulations have been conducted to study the scheme in which seed electron bunches with moderate energies are injected into a plasma waveguide and the DLA is performed by use of relatively low-power (0.5-2 TW) laser pulses. Selected bunch injection delays with respect to the laser pulse, bunch lengths, and bunch transverse sizes have been studied in a series of simulations of DLA in a plasma waveguide. The results show that the injection delay is important for controlling the final transverse properties of short electron bunches, but it also affects the final energy gain. With a long injected bunch length, the enhanced ion-focusing force helps to collimate the electrons and a relativ...

Lin, M -W; Chen, S -H; Jovanovic, I

2014-01-01T23:59:59.000Z

305

Photo of the Week: Lego Rendition of SLAC National Laboratory's Linear  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Lego Rendition of SLAC National Laboratory's Lego Rendition of SLAC National Laboratory's Linear Particle Accelerator Photo of the Week: Lego Rendition of SLAC National Laboratory's Linear Particle Accelerator February 4, 2013 - 10:26am Addthis At two miles long, SLAC's linear particle accelerator is a monster of a machine. But now, thanks to an old collection of Legos and some creative work by SLAC graphic designer Greg Stewart, the two-mile accelerator has been drastically reduced in size. After happening upon his Legos at home one night, Stewart decided to spend his evening designing, building and photographing this Lego diorama homage to the inside of the SLAC linac, a place that's 20 feet underground and not often seen by anyone besides the accelerator engineers who work there. SLAC's safety officers will even be pleased to see the Lego workers wearing their "PPE" (personal protective equipment, in this case helmets). See an actual photo of the SLAC linac. | Photo courtesy of Greg Stewart, SLAC National Accelerator Laboratory.

306

Broadband Single-Shot Electron Spectrometer for GeV-Class Laser Plasma Based Accelerators  

E-Print Network (OSTI)

of the 2007 Particle Accelerator Conference, p. 2978,Class Laser Plasma Based Accelerators K. Nakamura, ? W. Wan,Laser-plasma-based accelerators can provide electrons over a

Nakamura, K.

2008-01-01T23:59:59.000Z

307

Argonne Accelerator Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

Mission Mission The mission of the Argonne Accelerator Institute is centered upon the following related goals: Locate next generation accelerator facilities in Northern Illinois Advance accelerator technology Oversee a selected, strategic, lab-wide, and acclaimed accelerator R&D portfolio In order to accomplish the above goals, the institute has established five objectives. These are coupled to programmatic objectives, and are dependent on each other, but they serve to identify important areas for the institute to focus its activities. Educate the "next generation" of accelerator physicists and engineers Work with area Universities to establish Joint Appointments and Adjunct Professorships Identify students Provide research opportunities at Argonne Work with the US Particle Accelerator School

308

E-Print Network 3.0 - accelerated l5-s1 segment Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Compensation in Laser Particle Accelerators L.C. Steinhauer and W.D. Kimura STI... Optronics, 2755 Northup Way, Bellevue, WA 98004-1495 Abstract. Laser particle acceleration...

309

Uncatalyzed assembly of spherical particles from SV40 VP1 pentamers and linear dsDNA incorporates both low and high cooperativity elements  

SciTech Connect

The capsid of SV40 virion is comprised of 72 pentamers of the major capsid protein, VP1. We examined the synergism between pentamer-pentamer interaction and pentamer-DNA interaction using a minimal system of purified VP1 and a linear dsDNA 600-mer, comparing electrophoresis with electron microscopy and size exclusion chromatography. At low VP1/DNA ratios, large tubes were observed that apparently did not survive native agarose gel electrophoresis. As the VP1 concentration increased, electrophoretic migration was slower and tubes were replaced by 200 A diameter particles and excess free pentamer. At high VP1/DNA ratios, a progressively larger fraction of particles was similar to 450 A diameter virions. VP1 association with DNA is very strong compared to the concentrations in these experiments yet, paradoxically, stable complexes appear only at high ratios of VP1 to DNA. These data suggest a DNA saturation-dependent nucleation event based on non-specific pentamer-DNA interaction that controls assembly and the ultimate capsid geometry.

Mukherjee, Santanu [Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104 (United States); Kler, Stanislav; Oppenheim, Ariella [Department of Hematology, Hebrew University-Hadassah Medical School, 91120 Jerusalem (Israel); Zlotnick, Adam, E-mail: azlotnic@indiana.ed [Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104 (United States); Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47401 (United States)

2010-02-05T23:59:59.000Z

310

Vacuum electron acceleration by using two variable frequency laser pulses  

SciTech Connect

A method is proposed for producing a relativistic electron bunch in vacuum via direct acceleration by using two frequency-chirped laser pulses. We consider the linearly polarized frequency-chiped Hermit-Gaussian 0, 0 mode lasers with linear chirp in which the local frequency varies linearly in time and space. Electron motion is investigated through a numerical simulation using a three-dimensional particle trajectory code in which the relativistic Newton's equations of motion with corresponding Lorentz force are solved. Two oblique laser pulses with proper chirp parameters and propagation angles are used for the electron acceleration along the z-axis. In this way, an electron initially at rest located at the origin could achieve high energy, ?=319 with the scattering angle of 1.02{sup ?} with respect to the z-axis. Moreover, the acceleration of an electron in different initial positions on each coordinate axis is investigated. It was found that this mechanism has the capability of producing high energy electron microbunches with low scattering angles. The energy gain of an electron initially located at some regions on each axis could be greatly enhanced compared to the single pulse acceleration. Furthermore, the scattering angle will be lowered compared to the acceleration by using laser pulses propagating along the z-axis.

Saberi, H.; Maraghechi, B. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

2013-12-15T23:59:59.000Z

311

Carl Gagliardi Modern Particle  

NLE Websites -- All DOE Office Websites (Extended Search)

Carl Gagliardi Modern Particle Accelerators and Detectors A Household Survey Carl A. Gagliardi 2 Carl Gagliardi Alyson Clarke * High school All Star swimmer * My niece To do well...

312

Recent Advances in Plasma Acceleration  

SciTech Connect

The costs and the time scales of colliders intended to reach the energy frontier are such that it is important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators a drive beam, either laser or particle, produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultra-high accelerating fields over a substantial length to achieve a significant energy gain. More than 42 GeV energy gain was achieved in an 85 cm long plasma wakefield accelerator driven by a 42 GeV electron drive beam in the Final Focus Test Beam (FFTB) Facility at SLAC. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx}52 GV/m. This effectively doubles their energy, producing the energy gain of the 3 km long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. Prospects for a drive-witness bunch configuration and high-gradient positron acceleration experiments planned for the SABER facility will be discussed.

Hogan, Mark

2007-03-19T23:59:59.000Z

313

Collider-Accelerator Department  

NLE Websites -- All DOE Office Websites (Extended Search)

RHIC Tunnel and Magnets RHIC Tunnel and Magnets RHIC Tunnel and Magnets AGS Tunnel and Magnets NSRL Beamline RF Kicker Snake 200-MeV LINAC AGS Cold Snake Magnet About the Collider-Accelerator Department The mission of the Collider-Accelerator Department is to develop, improve and operate the suite of particle / heavy ion accelerators used to carry out the program of accelerator-based experiments at BNL; to support the experimental program including design, construction and operation of the beam transports to the experiments plus support of detector and research needs of the experiments; to design and construct new accelerator facilities in support of the BNL and national missions. The C-A Department supports an international user community of over 1500 scientists. The department performs all these functions in an environmentally responsible and safe manner under a rigorous conduct of operations approach.

314

Use of incomplete energy recovery for the energy compression of large energy spread charged particle beams  

DOE Patents (OSTI)

A method of energy recovery for RF-base linear charged particle accelerators that allows energy recovery without large relative momentum spread of the particle beam involving first accelerating a waveform particle beam having a crest and a centroid with an injection energy E.sub.o with the centroid of the particle beam at a phase offset f.sub.o from the crest of the accelerating waveform to an energy E.sub.full and then recovering the beam energy centroid a phase f.sub.o+Df relative to the crest of the waveform particle beam such that (E.sub.full-E.sub.o)(1+cos(f.sub.o+Df))>dE/2 wherein dE=the full energy spread, dE/2=the full energy half spread and Df=the wave form phase distance.

Douglas, David R. (Newport News, VA); Benson, Stephen V. (Yorktown, VA)

2007-01-23T23:59:59.000Z

315

Accelerator Toolbox for MATLAB  

SciTech Connect

This paper introduces Accelerator Toolbox (AT)--a collection of tools to model particle accelerators and beam transport lines in the MATLAB environment. At SSRL, it has become the modeling code of choice for the ongoing design and future operation of the SPEAR 3 synchrotron light source. AT was designed to take advantage of power and simplicity of MATLAB--commercially developed environment for technical computing and visualization. Many examples in this paper illustrate the advantages of the AT approach and contrast it with existing accelerator code frameworks.

Terebilo, Andrei

2001-05-29T23:59:59.000Z

316

Accelerator on a Chip: How It Works  

SciTech Connect

In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.

None

2014-06-30T23:59:59.000Z

317

ICFA: International Committee for Future Accelerators  

NLE Websites -- All DOE Office Websites (Extended Search)

ICFA - International Committee for Future Accelerators Membership Secretary What, Why, Who is ICFA? ICFA Meetings Panels Recent Linear Collider Activities Statements Related...

318

Desired Improvements in Laser-Plasma Accelerators  

NLE Websites -- All DOE Office Websites (Extended Search)

Wei Gai, John Power What's wrong with far field, or What do nano- lithography and accelerators have in common? r << r >> *Impossibility of linear in electric field...

319

Postacceleration Of Laser-Generated High Energy Protons Through Conventional Accelerator Linacs  

SciTech Connect

The post-acceleration of laser-generated protons through conventional drift tube linear accelerators has been simulated with the particle code Parmela. The proton source is generated on the rear surface of a target irradiated by an high-intensity (10{sup 19} W{center_dot}cm{sup -2}) short-pulse (350 fs) laser and focused by a microlens that allows selecting collimated protons at 7{+-}0.1 MeV with rms unnormalized emittance of 0.180 mm.mrad. The simulations show that protons can be accelerated by one drift tube linac tank to more than 14 MeV with unnormalized emittance growth of 8 in x and 22.6 in y directions when considering a total proton charge of 0.112 mA. This result shows for the first time that coupling between laser-plasma accelerators with traditional accelerators is possible, allowing a luminosity gain for the final beam.

Fuchs, Julien; Audebert, Patrick [Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-Ecole Polytechnique-Universite Paris VI, Palaiseau (France); Antici, Patrizio [Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-Ecole Polytechnique-Universite Paris VI, Palaiseau (France); Dipartimento di Energetica, Universita di Roma 'La Sapienza', Via Scarpa 14-16, 00165 Roma (Italy); Fazi, Mauro; Migliorati, Mauro; Palumbo, Luigi [Dipartimento di Energetica, Universita di Roma 'La Sapienza', Via Scarpa 14-16, 00165 Roma (Italy); Lombardi, Augusto [ATreP via Perini 181, 38100, Trento (Italy)

2008-06-24T23:59:59.000Z

320

Radioactive waste management and decommissioning of accelerator facilities  

Science Journals Connector (OSTI)

......produced in nuclear power plants and in accelerators is that there...high-energy accelerator is of solid...of magnets, vacuum pipes and components...of particle accelerators are: iron...content. Several nuclear processes contribute......

Luisa Ulrici; Matteo Magistris

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

PROTON ACCELERATION AT OBLIQUE SHOCKS  

SciTech Connect

Acceleration at the shock waves propagating oblique to the magnetic field is studied using a recently developed theoretical/numerical model. The model assumes that resonant hydromagnetic wave-particle interaction is the most important physical mechanism relevant to motion and acceleration of particles as well as to excitation and damping of waves. The treatment of plasma and waves is self-consistent and time dependent. The model uses conservation laws and resonance conditions to find where waves will be generated or damped, and hence particles will be pitch-angle-scattered. The total distribution is included in the model and neither introduction of separate population of seed particles nor some ad hoc escape rate of accelerated particles is needed. Results of the study show agreement with diffusive shock acceleration models in the prediction of power spectra for accelerated particles in the upstream region. However, they also reveal the presence of spectral break in the high-energy part of the spectra. The role of the second-order Fermi-like acceleration at the initial stage of the acceleration is discussed. The test case used in the paper is based on ISEE-3 data collected for the shock of 1978 November 12.

Galinsky, V. L.; Shevchenko, V. I., E-mail: vit@ucsd.edu [ECE Department, UC San Diego, MC 407, La Jolla, CA 92093-0407 (United States)

2011-06-20T23:59:59.000Z

322

Accelerator Research Department BAccelerator Research Department B E163: Laser Acceleration  

E-Print Network (OSTI)

1 Accelerator Research Department BAccelerator Research Department B E163: Laser Acceleration, D. R. Walz Stanford Linear Accelerator Center R. L. Byer, T. Plettner Stanford University * Spokesman. #12;2 Accelerator Research Department B Outline · Introduction ­­ Future requirements for high

Wechsler, Risa H.

323

ORELA accelerator facility  

NLE Websites -- All DOE Office Websites (Extended Search)

The Oak Ridge Electron Linear Accelerator The Oak Ridge Electron Linear Accelerator Pulsed Neutron Source The ORELA is a powerful electron accelerator-based neutron source located in the Physics Division of Oak Ridge National Laboratory. It produces intense, nanosecond bursts of neutrons, each burst containing neutrons with energies from 10e-03 to 10e08 eV. ORELA is operated about 1200 hours per year and is an ORNL User Facility open to university, national laboratory and industrial scientists. The mission of ORELA has changed from a recent focus on applied research to nuclear astrophysics. This is an area in which ORELA has historically been very productive: most of the measurements of neutron capture cross sections necessary for understanding heavy element nucleosynthesis through the slow neutron capture process (s-process) have

324

ACCELERATORS: ENGINES FOR TRAVERSING A LARGE AND OFTEN DIFFICULT LANDSCAPE  

E-Print Network (OSTI)

California. ACCELERATORS: ENGINES FOR TRAVERSING A LARGE ANDthat go with them, are from: “Engines of Discovery: Particle

Sessler, Andrew M.

2014-01-01T23:59:59.000Z

325

Fermi National Accelerator Laboratory September 2013  

NLE Websites -- All DOE Office Websites (Extended Search)

Technologies developed at Fermilab will be used in the next generation of particle accelerators and will spur innovation to meet the challenges of America's future. SRF...

326

Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude  

DOE Patents (OSTI)

A beam current limiter is disclosed for sensing and limiting the beam current in a particle accelerator, such as a cyclotron or linear accelerator, used in scientific research and medical treatment. A pair of independently operable capacitive electrodes sense the passage of charged particle bunches to develop an RF signal indicative of the beam current magnitude produced at the output of a bunched beam accelerator. The RF signal produced by each sensing electrode is converted to a variable DC voltage indicative of the beam current magnitude. The variable DC voltages thus developed are compared to each other to verify proper system function and are further compared to known references to detect beam currents in excess of pre-established limits. In the event of a system malfunction, or if the detected beam current exceeds pre-established limits, the beam current limiter automatically inhibits further accelerator operation. A high Q tank circuit associated with each sensing electrode provides a narrow system bandwidth to reduce noise and enhance dynamic range. System linearity is provided by injecting, into each sensing electrode, an RF signal that is offset from the bunching frequency by a pre-determined beat frequency to ensure that subsequent rectifying diodes operate in a linear response region. The system thus provides a large dynamic range in combination with good linearity. 6 figs.

Bogaty, J.M.; Clifft, B.E.; Bollinger, L.M.

1995-08-08T23:59:59.000Z

327

Future Accelerators (?)  

E-Print Network (OSTI)

I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

John Womersley

2003-08-09T23:59:59.000Z

328

Note on accelerated detectors  

Science Journals Connector (OSTI)

The Unruh result, on the thermal-like behavior of particle detectors under a uniformly accelerated state of motion, is found by a different method which does not involve field quantization in a metric with a horizon. The result is extended to other situations.

P. Meyer

1978-07-15T23:59:59.000Z

329

The engineering needed for particle physics  

Science Journals Connector (OSTI)

...Chao A. W. , M. Tigner 1998 Handbook of accelerator physics and engineering. Singapore...Lee, S. Y. 1999 Accelerator physics. Singapore: World Scientific...of particle accelerators and physics equipment. In Proc. 1st Int...

2012-01-01T23:59:59.000Z

330

BNL | Our History: Accelerators  

NLE Websites -- All DOE Office Websites (Extended Search)

> See also: Reactors > See also: Reactors A History of Leadership in Particle Accelerator Design Cosmotron Cosmotron (1952-1966) Early in Brookhaven Lab history, the consortium of universities responsible for founding the new research center, decided that Brookhaven should provide leading facilities for high energy physics research. In April 1948, the Atomic Energy Commission approved a plan for a proton synchrotron to be built at Brookhaven. The new machine would accelerate protons to previously unheard of energies-comparable to the cosmic rays showering the earth's outer atmosphere. It would be called the Cosmotron. The Cosmotron was the first accelerator in the world to send particles to energies in the billion electron volt, or GeV, region. The machine reached its full design energy of 3.3 GeV in 1953.

331

Laser acceleration of ion beams  

E-Print Network (OSTI)

We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.

I. A. Egorova; A. V. Filatov; A. V. Prozorkevich; S. A. Smolyansky; D. B. Blaschke; M. Chubaryan

2007-02-01T23:59:59.000Z

332

Current trends in non-accelerator particle physics: 1, Neutrino mass and oscillation. 2, High energy neutrino astrophysics. 3, Detection of dark matter. 4, Search for strange quark matter. 5, Magnetic monopole searches  

SciTech Connect

This report is a compilation of papers reflecting current trends in non-accelerator particle physics, corresponding to talks that its author was invited to present at the Workshop on Tibet Cosmic Ray Experiment and Related Physics Topics held in Beijing, China, April 4--13, 1995. The papers are entitled `Neutrino Mass and Oscillation`, `High Energy Neutrino Astrophysics`, `Detection of Dark Matter`, `Search for Strange Quark Matter`, and `Magnetic Monopole Searches`. The report is introduced by a survey of the field and a brief description of each of the author`s papers.

He, Yudong [California Univ., Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

1995-07-01T23:59:59.000Z

333

Sequentially pulsed traveling wave accelerator  

DOE Patents (OSTI)

A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA); Poole, Brian R. (Tracy, CA)

2009-08-18T23:59:59.000Z

334

Thomas Jefferson National Accelerator Facility Site Tour - Accelerator Map  

NLE Websites -- All DOE Office Websites (Extended Search)

Counting House Free Electron Accelerator Facility Machine Control Center Physics Storage Building North Linear Accelerator South Linear Accelerator VEPCO Substation Machine Control Center Annex Machine Control Center Annex II North Access Building South Access Building Central Helium Liquefier Injector Hall A Truck Ramp Hall B Truck Ramp Hall C Truck Ramp Experimental Hall A Experimental Hall B Experimental Hall C East Arc West Arc Counting House Free Electron Accelerator Facility Machine Control Center Physics Storage Building North Linear Accelerator South Linear Accelerator VEPCO Substation Machine Control Center Annex Machine Control Center Annex II North Access Building South Access Building Central Helium Liquefier Injector Hall A Truck Ramp Hall B Truck Ramp Hall C Truck Ramp Experimental Hall A Experimental Hall B Experimental Hall C East Arc West Arc Science Education Jefferson Lab Jefferson Lab Home Search Jefferson Lab Contact Jefferson Lab Science Education Home Teacher Resources Student Zone Games and Puzzles Science Cinema Programs and Events Search Education Privacy and Security Notice Jefferson Lab Site Tour Guided Tour Site Map Accelerator Area Map Administrative Area Map Tour Index

335

Subcritical Fission Reactor Based on Linear Collider  

E-Print Network (OSTI)

The beams of Linear Collider after main collision can be utilized to build an accelerator--driven sub--critical reactor.

I. F. Ginzburg

2005-07-29T23:59:59.000Z

336

Fermilab | Science | Particle Physics 101 | Ask a Scientist  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum fields, superstrings and all that. Accelerators Bringing particles to almost the speed of light. Particle detectors Capturing the tracks of particles. Physics of the...

337

SLAC linear collider  

SciTech Connect

A brief description of the proposed SLAC Linear Collider is given. This machine would investigate the possibilities and limitations of Linear Colliders while at the same time producing thousands of Z/sup 0/ particles per day for the study of the weak interactions.

Hollebeek, R.

1980-06-01T23:59:59.000Z

338

Linear Collider Collaboration Tech Notes  

NLE Websites -- All DOE Office Websites (Extended Search)

Notes Notes LCC - 0018, 15/06/99 Rev B, June 2002 Correct Account of RF Deflections in Linac Acceleration June 15, 1999 G.V. Stupakov Stanford Linear Accelerator Center Stanford, California Abstract: During acceleration in the linac structure, the beam not only increases its longitudinal momentum, but also experiences a transverse kick from the accelerating mode which is linear in accelerating gradient. This effect is neglected in such computer codes as LIAR and TRANSPORT. We derived the Hamiltonian equations that describe the effect of RF deflection into the acceleration process and included it into the computational engine of LIAR. By comparing orbits for the NLC main linac, we found that the difference between the two algorithms is about 10\%. The effect will be more pronounced at smaller

339

Pulse - Accelerator Science in Medicine  

NLE Websites -- All DOE Office Websites (Extended Search)

t he future of accelerator physics isn’t just for physicists. As in the past, tomorrow’s discoveries in particle accelerator science may lead to unexpected applications for medical diagnosis, healing and the understanding of human biology. t he future of accelerator physics isn’t just for physicists. As in the past, tomorrow’s discoveries in particle accelerator science may lead to unexpected applications for medical diagnosis, healing and the understanding of human biology. Breakthroughs in the technology of superconducting magnets, nanometer beams, laser instrumentation and information technology will give high-energy physicists new accelerators to explore the deepest secrets of the universe: the ultimate structure of matter and the nature of space and time. But breakthroughs in accelerator science may do more than advance the exploration of particles and forces. No field of science is an island. Physics, astronomy, chemistry, biology, medicine— all interact in the continuing human endeavor to explore and understand our world and ourselves. Research at high-energy physics laboratories will lead to the next generation of particle accelerators—and perhaps to new tools for medical science.

340

Accelerator Division  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Science Particle Physics Neutrinos Fermilab and the LHC Dark matter and dark energy More fundamental particles and forces Theory Scientific Computing Research &...

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

E-Print Network 3.0 - accelerator physics experiments Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

facilities for biology and material sciences. Beam physics--study of beams in accelerators... -ray facilities, and the injector linear accelerator where a pioneering...

342

E-Print Network 3.0 - accelerated beam experiments Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Summary: radiation facilities for biology and material sciences. Beam physics--study of beams in accelerators... -ray facilities, and the injector linear accelerator where a...

343

Acceleration Fund  

NLE Websites -- All DOE Office Websites (Extended Search)

for these Venture Acceleration Fund awards, which have already produced a significant return on investment for the regional companies that have received them," said Padilla....

344

Linear Accelerators for Protons: New Developments  

Science Journals Connector (OSTI)

...Stand-ard methods of perturbation theory are used to describe and predict...to the same frequency (the theory had sug-gested that this would...have been in-vestigating the basic technology of superconducting...Ising, Arkiv Mat. Astron. Fysik 18, 1 (1924) [English translation...

Darragh E. Nagle

1967-07-14T23:59:59.000Z

345

Jeffrey S. Oishi Stanford Linear Accelerator Center  

E-Print Network (OSTI)

triangles: integration of resistive term Magnetic helicity measures the linkage of magnetic field lines geometries and equations #12;Disks can create their own fields even when the magnetic Prandtl Number Pm of Natural History Magnetic Helicity and Astrophysical Disk Dynamos #12;Astrophysical disks transport

346

Radiation from accelerated branes  

Science Journals Connector (OSTI)

The radiation emitted by accelerated fundamental strings and D-branes is studied within the linear approximation to the supergravity limit of string theory. We show that scalar, gauge field and gravitational radiation is generically emitted by such branes. In the case where an external scalar field accelerates the branes, we derive a Larmor-type formula for the emitted scalar radiation and study the angular distribution of the outgoing energy flux. The classical radii of the branes are calculated by means of the corresponding Thompson scattering cross sections. Within the linear approximation, the interaction of the external scalar field with the velocity fields of the branes gives a contribution to the observed gauge field and gravitational radiation.

Mohab Abou-Zeid and Miguel S. Costa

2000-04-26T23:59:59.000Z

347

Conception design of helium ion FFAG accelerator with induction accelerating cavity  

E-Print Network (OSTI)

In the recent decades of particle accelerator R&D area, fixed field alternating gradient (FFAG) accelerator has become a highlight for some advantages of its higher beam intensity and lower cost, although there are still some technical challenges. In this paper, FFAG accelerator is adopted to accelerate helium ion beam on the one hand for the study of helium embrittlement on fusion reactor envelope material and on the other hand for promoting the conception research and design of FFAG accelerator and exploring the possibility of developing high power FFAG accelerators. The conventional period focusing unit of helium ion FFAG accelerator and three-dimensional model of the large aperture combinatorial magnet by OPERA-TOSCA are given. For low energy and low revolution frequency, induction acceleration is proposed to replace conventional radio frequency(RF) acceleration for helium ion FFAG accelerator, which avoids the potential breakdown of acceleration field caused by wake field and improves the acceleratio...

Huan-li, Luo; Xiang-qi, Wang; Hong-Liang, Xu

2013-01-01T23:59:59.000Z

348

E-Print Network 3.0 - accelerator physics theory Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

physics and astrophysics. It is now known that particle acceleration can occur... the small-scale acceleration physics can be incorpo- rated into the large-scale coronal...

349

E-Print Network 3.0 - accelerating beam stability Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

(ARD) has the mission to develop accelerator Summary: between rf systems and particle beams, applications of control techniques to asses system stability... Wakefield Accelerator...

350

Commissioning of Photon Beams of a Flattening Filter-Free Linear Accelerator and the Accuracy of Beam Modeling Using an Anisotropic Analytical Algorithm;TrueBeam; Flattening filter free; Commissioning; Anisotropic analytical algorithm  

SciTech Connect

Purpose: To investigate dosimetric characteristics of a new linear accelerator designed to deliver flattened, as well as flattening filter-free (FFF), beams. To evaluate the accuracy of beam modeling under physical conditions using an anisotropic analytical algorithm. Methods and Materials: Dosimetric data including depth dose curves, profiles, surface dose, penumbra, out-of-field dose, output, total and scatter factors were examined for four beams (X6, X6FFF, X10, and X10FFF) of Varian's TrueBeam machine. Beams modeled by anisotropic analytical algorithm were compared with measured dataset. Results: FFF beams have lower mean energy (tissue-phantom ratio at the depths of 20 and 10 cm (TPR 20/10): X6, 0.667; X6FFF, 0.631; X10, 0.738; X10FFF, 0.692); maximum dose is located closer to the surface; and surface dose increases by 10%. FFF profiles have sharper but faster diverging penumbra. For small fields and shallow depths, dose outside a field is lower for FFF beams; however, the advantage fades with increasing phantom scatter. Output increases 2.26 times for X6FFF and 4.03 times for X10FFF and is less variable with field size; collimator exchange effect is reduced. A good agreement between modeled and measured data is observed. Criteria of 2% depth-dose and 2-mm distance-to-agreement are always met. Conclusion: Reference dosimetric characteristics of TrueBeam photon bundles were obtained, and successful modeling of the beams was achieved.

Hrbacek, Jan, E-mail: jan.hrbacek@usz.ch [Department of Radiation Oncology, University Hospital Zuerich, Zuerich (Switzerland); Lang, Stephanie; Kloeck, Stephan [Department of Radiation Oncology, University Hospital Zuerich, Zuerich (Switzerland)

2011-07-15T23:59:59.000Z

351

The ‘Oh my God’ particles  

Science Journals Connector (OSTI)

Every so often a particle from space hit’s Earth’s atmosphere with an energy exceeding anything that a manmade accelerator can achieve. Where do these particles come from? And how do they get to be so energeti...

Dr. Stephen Webb

2012-01-01T23:59:59.000Z

352

LASER-PLASMA-ACCELERATOR-BASED COLLIDERS C. B. Schroeder  

E-Print Network (OSTI)

LASER-PLASMA-ACCELERATOR-BASED COLLIDERS C. B. Schroeder , E. Esarey, Cs. T´oth, C. G. R. Geddes-generation linear col- lider based on laser-plasma-accelerators are discussed, and a laser-plasma-accelerator gamma-gamma () collider is considered. An example of the parameters for a 0.5 TeV laser-plasma-accelerator collider

Geddes, Cameron Guy Robinson

353

Accelerate Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

the next year, the U.S. Department of Energy, the Council on Competitiveness and the Alliance to Save Energy will join forces to undertake Accelerate Energy Productivity 2030 - an...

354

An Alternative to Particle Dark Matter  

E-Print Network (OSTI)

We propose an alternative to particle dark matter that borrows ingredients of MOdified Newtonian Dynamics (MOND) while adding new key components. The first new feature is a dark matter fluid, in the form of a scalar field with small equation of state and sound speed. This component is critical in reproducing the success of cold dark matter for the expansion history and the growth of linear perturbations, but does not cluster significantly on non-linear scales. Instead, the missing mass problem on non-linear scales is addressed by a modification of the gravitational force law. The force law approximates MOND at large and intermediate accelerations, and therefore reproduces the empirical success of MOND at fitting galactic rotation curves. At ultra-low accelerations, the force law reverts to an inverse-square-law, albeit with a larger Newton's constant. This latter regime is important in galaxy clusters and is consistent with their observed isothermal profiles, provided the characteristic acceleration scale of MOND is mildly varying with scale or mass, such that it is ~12 times higher in clusters than in galaxies. We present an explicit relativistic theory in terms of two scalar fields. The first scalar field is governed by a Dirac-Born-Infeld action and behaves as a dark matter fluid on large scales. The second scalar field also has single-derivative interactions and mediates a fifth force that modifies gravity on non-linear scales. Both scalars are coupled to matter via an effective metric that depends locally on the fields. The form of this effective metric implies the equality of the two scalar gravitational potentials, which ensures that lensing and dynamical mass estimates agree. Further work is needed in order to make both the acceleration scale of MOND and the fraction at which gravity reverts to an inverse-square law explicitly dynamical quantities, varying with scale or mass.

Justin Khoury

2014-12-11T23:59:59.000Z

355

International Workshop on Linear Colliders 2010  

ScienceCinema (OSTI)

IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland) This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop Secretariat  IWLC2010 is hosted by CERN

None

2011-10-06T23:59:59.000Z

356

Discovery of Optical Emission in the Hotspots of Three 3CR Quasars: High-Energy Particle Acceleration in Powerful Radio Hotspots  

E-Print Network (OSTI)

Archival Hubble Space Telescope WFPC2 images were used to search for optical emission associated with the radio jets of a number of luminous quasars. From this search, we report new optical hotspot detections in the well-known blazar 3C~454.3 and the lobe-dominated quasars 3C~275.1 and 3C~336. We also find optical emission in the vicinity of the hotspot in 3C~208, but believe this is a chance alignment. Optical emission from the arcsecond-scale jet in 3C~454.3 is also detected. Multi-frequency archival radio data from the VLA and MERLIN are analyzed, and the synchrotron spectra of these high-power hotspots are presented. We estimate that their break frequencies are in the range of $10^{10}-10^{11}$ Hz, with large uncertainties due to the wide gap in frequency coverage between the radio and optical bands. We also calculate their equipartition magnetic fields, and find that the anti-correlation between break frequency and magnetic field found by Brunetti et al. for lower power hotspots extends to these high power hotspots. This supports their model of hot-spots based on shock acceleration and synchrotron losses.

C. C. Cheung; J. F. C. Wardle; T. Chen

2005-03-29T23:59:59.000Z

357

Gamma-Ray and Hard X-Ray Emission from Pulsar-Aided Supernovae as a Probe of Particle Acceleration in Embryonic Pulsar Wind Nebulae  

E-Print Network (OSTI)

It has been suggested that some classes of luminous supernovae (SNe) and gamma-ray bursts (GRBs) are driven by newborn magnetars. Fast-rotating proto-neutron stars have also been of interest as potential sources of gravitational waves (GWs). We show that for a range of rotation periods and magnetic fields, hard X rays and GeV gamma rays provide us with a promising probe of pulsar-aided SNe. It is observationally known that young pulsar wind nebulae (PWNe) in the Milky Way are very efficient lepton accelerators. We argue that, if embryonic PWNe satisfy similar conditions at early stages of SNe (in ~1-10 months after the explosion), external inverse-Compton emission via upscatterings of SN photons is naturally expected in the GeV range as well as broadband synchrotron emission. To fully take into account the Klein-Nishina effect and two-photon annihilation process that are important at early times, we perform detailed calculations including electromagnetic cascades. Our results suggest that hard X-ray telescope...

Murase, Kohta; Kiuchi, Kenta; Bartos, Imre

2014-01-01T23:59:59.000Z

358

Pulse - Accelerator Science in Medicine  

NLE Websites -- All DOE Office Websites (Extended Search)

t the forefront of biomedical research, medical scientists use particle accelerators to explore the structure of biological molecules. They use the energy that charged particles emit when accelerated to nearly the speed of light to create one of the brightest lights on earth, 30 times more powerful than the sun and focused on a pinpoint. t the forefront of biomedical research, medical scientists use particle accelerators to explore the structure of biological molecules. They use the energy that charged particles emit when accelerated to nearly the speed of light to create one of the brightest lights on earth, 30 times more powerful than the sun and focused on a pinpoint. Deciphering the structure of proteins is key to understanding biological processes and healing disease. To determine a proteinÂ’s structure, researchers direct the beam from an accelerator called a synchrotron through a protein crystal. The crystal scatters the beam onto a detector. From the pattern of scattering, computers calculate the position of every atom in the protein molecule and create a 3-D image of the molecule.

359

E-Print Network 3.0 - accelerator personnel radiatsionnye Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Linear Accelerator Center Collection: Physics 42 Advanced Photon Source Conduct of Operations Manual Summary: . . . . . . . . . . . . . . . . . . . 26 4.5 Beamline...

360

Accelerated Testing Validation  

E-Print Network (OSTI)

the University of California. Accelerated Testing Validationmaterials requires relevant Accelerated Stress Tests (ASTs),

Mukundan, Rangachary

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Elementary Particles  

NLE Websites -- All DOE Office Websites (Extended Search)

Elementary Particles Elementary Particles Elementary Particles Detectors Accelerators Visit World Labs For Children - for younger people Electric Forces & Fields For Children The Electric Force For Children Electric Force Fields For Children Charges and Fields For Children Vibrating Charges and Electromagnetic Waves Electrons For Older People The Discovery of the Electron Traveling Waves For Older People Waves and Wave-Like Motion For Children Catch the Wave For Children Vibrating Charges and Electromagnetic Waves For Children Electromagnetic Waves Standing Waves For Older People Physics 128 Lecture Standing Waves For Older People Resonance in Strings and Springs For Older People Standing Wave - 1st Harmonic For Older People Standing Wave - 2nd Harmonic Atom For Older People Bohr Atom

362

US plan for proton accelerator to produce tritium for warheads  

Science Journals Connector (OSTI)

... construction of a huge linear proton accelerator for the production of tritium; it may be powered by excess electricity from hydroelectric sources.

David Swinbanks

1989-02-02T23:59:59.000Z

363

Application Acceleration  

NLE Websites -- All DOE Office Websites (Extended Search)

Acceleration Acceleration on Current and Future Cray Platforms Alice Koniges, Robert Preissl, Jihan Kim, Lawrence Berkeley National Laboratory David Eder, Aaron Fisher, Nathan Masters, Velimir Mlaker, Lawrence Livermore National Laboratory Stephane Ethier, Weixing Wang, Princeton Plasma Physics Laboratory Martin Head-Gordon, University of California, Berkeley and Nathan Wichmann, Cray Inc. ABSTRACT: Application codes in a variety of areas are being updated for performance on the latest architectures. We describe current bottlenecks and performance improvement areas for applications including plasma physics, chemistry related to carbon capture and sequestration, and material science. We include a variety of methods including advanced hybrid parallelization using multi-threaded MPI, GPU acceleration, libraries and auto- parallelization compilers. KEYWORDS: hybrid

364

Ion acceleration in a plasma focus  

Science Journals Connector (OSTI)

The electric and magnetic fields associated with anomalous diffusion to the axis of a linear plasma discharge are used to compute representative ion trajectories. Substantial axial acceleration of the ions is demonstrated.

S. Peter Gary

1974-01-01T23:59:59.000Z

365

Fourier Accelerated Conjugate Gradient Lattice Gauge Fixing  

E-Print Network (OSTI)

We provide details of the first implementation of a non-linear conjugate gradient method for Landau and Coulomb gauge fixing with Fourier acceleration. We find clear improvement over the Fourier accelerated steepest descent method, with the average time taken for the algorithm to converge to a fixed, high accuracy, being reduced by a factor of 2 to 4.

R. J. Hudspith

2014-05-22T23:59:59.000Z

366

Interplay of Boltzmann equation and continuity equation for accelerated electrons in solar flares  

E-Print Network (OSTI)

During solar flares a large amount of electrons are accelerated within the plasma present in the solar atmosphere. Accurate measurements of the motion of these electrons start becoming available from the analysis of hard X-ray imaging-spectroscopy observations. In this paper, we discuss the linearized perturbations of the Boltzmann kinetic equation describing an ensemble of electrons accelerated by the energy release occurring during solar flares. Either in the limit of high energy or at vanishing background temperature such an equation reduces to a continuity equation equipped with an extra force of stochastic nature. This stochastic force is actually described by the well known energy loss rate due to Coulomb collision with ambient particles, but, in order to match the collision kernel in the linearized Boltzmann equation it needs to be treated in a very specific manner. In the second part of the paper the derived continuity equation is solved with some hyperbolic techniques, and the obtained solution is wr...

Codispoti, Anna

2015-01-01T23:59:59.000Z

367

ACCELERATOR R&D S U M M A R Y  

E-Print Network (OSTI)

1 ACCELERATOR R&D P5 @ BNL 3/6/08 S U M M A R Y Medium & Longer Term [AARD = Advanced Accelerator R&D] #12;2 · Accelerators remain an essential component in Elementary Particle Physics Research · Accelerator capabilities are prominent in defining the frontiers of Elementary Particle Science · EPP2010

368

Argonne Accelerator Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

CWDD - Continuous Wave Deuterium Demonstrator CWDD - Continuous Wave Deuterium Demonstrator The Continuous Wave Deuterium Demonstrator (CWDD) accelerator, a cryogenically-cooled (26K) linac, was designed to accelerate 80 mA cw of D to 7.5 MeV. CWDD was being built to demonstrate the lauching of a beam with characteristics suitable for a space-based neutral particle-beam (NPB). A considerable amount of hardware was constructed and installed in the Argonne-based facility, and major performance milestones were achieved before program funding ended in October 1993. References - Document Access Guide Continuous Wave Deuterium Demonstrator Final Design Review, Grumman Space Systems, Grumman-Culham Laboratory, Los Alamos (1989). (Located in the Argonne Research Library) Recommissioning and first operation of the CWDD injector at Argonne

369

E-Print Network 3.0 - accelerator experimental tests Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Collection: Physics 6 Research in: Experimental Photonuclear Physics Summary: & Phenomenology Particle Astrophysics & Cosmology Accelerator Physics Health Physics...

370

First Director Named for Center for Accelerator Science | Jefferson...  

NLE Websites -- All DOE Office Websites (Extended Search)

- is envisioned as a springboard for innovations. In addition to probing the nature of matter, particle accelerators are being used in diverse and rapidly growing fields....

371

The evolution of high energy accelerators  

SciTech Connect

In this lecture I would like to trace how high energy particle accelerators have grown from tools used for esoteric small-scale experiments to gigantic projects being hotly debated in Congress as well as in the scientific community.

Courant, E.D.

1989-10-01T23:59:59.000Z

372

Accelerator target  

DOE Patents (OSTI)

A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression. 5 figs.

Schlyer, D.J.; Ferrieri, R.A.; Koehler, C.

1999-06-29T23:59:59.000Z

373

Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator  

SciTech Connect

Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped electron bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped electrons. Next, the sixth chapter introduces suggestions for future trapped electron experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to electron trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel plasma, which if produced could solve some of the remaining issues for a plasma-based collider.

Kirby, Neil; /SLAC

2009-10-30T23:59:59.000Z

374

The Physics of Cosmic Acceleration  

E-Print Network (OSTI)

by Annual Reviews. All rights reserved 0163-8998/09/1123-0397$20.00 Key Words cosmology, dark energy · Our comprehensive search FurtherANNUAL REVIEWS #12;Dark energy: a negative-pressure fluid comprising, particle theory, gravitational theory Abstract The discovery that the cosmic expansion is accelerating has

Weijgaert, Rien van de

375

Accelerators for Intensity Frontier Research  

SciTech Connect

In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.

Derwent, Paul; /Fermilab

2012-05-11T23:59:59.000Z

376

About Accelerators | Jefferson Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerator Brochure top-right bottom-left-corner bottom-right-corner About Accelerators Jefferson Lab is home to two superconducting radiofrequency accelerators: the...

377

GPU accelerated cardiac electrophysiology  

E-Print Network (OSTI)

OF THE THESIS GPU Accelerated Cardiac Electrophysiology bySAN DIEGO GPU Accelerated Cardiac Electrophysiology A thesistoolkit for developing GPU accelerated programs called CUDA,

Lionetti, Fred

2010-01-01T23:59:59.000Z

378

Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies  

SciTech Connect

The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization for software development and applications accounts for the natural domain areas (beam dynamics, electromagnetics, and advanced acceleration), and all areas depend on the enabling technologies activities, such as solvers and component technology, to deliver the desired performance and integrated simulation environment. The ComPASS applications focus on computationally challenging problems important for design or performance optimization to all major HEP, NP, and BES accelerator facilities. With the cost and complexity of particle accelerators rising, the use of computation to optimize their designs and find improved operating regimes becomes essential, potentially leading to significant cost savings with modest investment.

Spentzouris, P.; /Fermilab; Cary, J.; /Tech-X, Boulder; McInnes, L.C.; /Argonne; Mori, W.; /UCLA; Ng, C.; /SLAC; Ng, E.; Ryne, R.; /LBL, Berkeley

2011-11-14T23:59:59.000Z

379

1 Industrial Electron Accelerators type ILU for Industrial Technologies  

E-Print Network (OSTI)

1 Industrial Electron Accelerators type ILU for Industrial Technologies The present work describes industrial electron accelerators of the ILU family. Their main parameters, design, principle of action the pulse linear accelerators type ILU are developed and supplied to the industry. The ILU machines

380

ONE GEV BEAM ACCELERATION IN A ONE METER LONG  

E-Print Network (OSTI)

ONE GEV BEAM ACCELERATION IN A ONE METER LONG PLASMA CELL A Proposal to the Stanford Linear. A single SLC bunch is used to both induce wakefields in the one meter long plasma and to witness that are needed to apply high-gradient plasma wakefield acceleration to large scale accelerators. The one meter

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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Kwok Ko SLAC National Accelerator Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Kwok Ko Kwok Ko SLAC National Accelerator Laboratory Work supported by US DOE Offices of HEP, ASCR and BES under contract AC02-76SF00515. Large Scale Computing and Storage Requirements for High Energy Physics Rockville, MD, November 27-28, 2012 Present and Future Computing Requirements for Advanced Modeling for Particle Accelerator 1. Advanced Modeling for Particle Accelerators (AMPA) NERSC Repositories: m349 Principal Investigator: K. Ko Senior Investigators: SLAC - L. Ge, Z. Li, C. Ng, L. Xiao, FNAL - A. Lunin, Jlab - H. Wang, BNL - S. Belomestnykh, ANL - A. Nassiri

382

A theory of metrics with maximal acceleration  

E-Print Network (OSTI)

We present a geometric theory for spacetimes whose world lines associated with physical particles have an upper bound for the proper acceleration. After some fundamental remarks on the requirements that classical dynamics for point particles must hold good, the notion of generalized metric and a theory of maximal acceleration are introduced. A perturbative approach to metrics of maximal acceleration is discussed. Then several of their physical and kinematical properties are investigated. These include a discussion of the fundamental causal theory concepts and the introduction of the associated notions of Euclidean length and celerity function. Finally, we discuss the corresponding modification of the Einstein's mass-energy relation.

Ricardo Gallego Torromé

2014-03-06T23:59:59.000Z

383

SuperB Progress Report for Accelerator  

SciTech Connect

This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name 'SuperB'. This project builds on a long history of successful e+e- colliders built around the world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called 'crab waist'. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and national laboratories. In Italy these may include INFN Frascati and the University of Pisa, in the United States SLAC, LBNL, BNL and several universities, in France IN2P3, LAPP, and Grenoble, in Russia BINP, in Poland Krakow University, and in the UK the Cockcroft Institute. The construction time for this collider is a total of about four years. The new tunnel can be bored in about a year. The new accelerator components can be built and installed in about 4 years. The shipping of components from PEP-II at SLAC to Italy will take about a year. A new linac and damping ring complex for the injector for the rings can be built in about three years. The commissioning of this new accelerator will take about a year including the new electron and positron sources, new linac, new damping ring, new beam transport lines, two new collider rings and the Interaction Region. The new particle physics detector can be commissioned simultaneously with the accelerator. Once beam collisions start for particle physics, the luminosity will increase with time, likely reaching full design specifications after about two to three years of operation. After construction, the operation of the collider will be the responsibility of the Italian INFN governmental agency. The intent is to run this accelerator about ten months each year with about one month for accelerator turn-on and nine months for colliding beams. The collider will need to operate for about 10 years to provide the required 50 ab{sup -1} requested by the detector collaboration. Both beams as anticipated in this collider will have properties that are excellent for use as sources for synchrotron radiation (SR). The expected photon properties are comparable to those of PETRA-3 or NSLS-II. The beam lines and user facilities needed to carry out this SR program are being investigated.

Biagini, M.E.; Boni, R.; Boscolo, M.; Buonomo, B.; Demma, T.; Drago, A.; Esposito, M.; Guiducci, S.; Mazzitelli, G.; Pellegrino, L.; Preger, M.A.; Raimondi, P.; Ricci, R.; Rotundo, U.; Sanelli, C.; Serio, M.; Stella, A.; Tomassini, S.; Zobov, M.; /Frascati; Bertsche, K.; Brachman, A.; /SLAC /Novosibirsk, IYF /INFN, Pisa /Pisa U. /Orsay, LAL /Annecy, LAPP /LPSC, Grenoble /IRFU, SPP, Saclay /DESY /Cockroft Inst. Accel. Sci. Tech. /U. Liverpool /CERN

2012-02-14T23:59:59.000Z

384

The Particle Adventure | How do we detect what's happening? | The  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerators and particle detectors > How do we detect what's happening? > Accelerators and particle detectors > How do we detect what's happening? > The physicists tool: The accelerator The physicists tool: The accelerator Physicists can't use light to explore atomic and sub-atomic structures because light's wavelength is too long. However, since ALL particles have wave properties, physicists can use particles as their probes. In order to see the smallest particles, physicists need a particle with the shortest possible wavelength. However, most of the particles around us in the natural world have fairly long wavelengths. How do physicists decrease a particle's wavelength so that it can be used as a probe? A particle's momentum and its wavelength are inversely related High-energy physicists apply this principle when they use particle accelerators to increase the momentum of a probing particle, thus decreasing its wavelength.

385

Chemical Accelerators The phrase "chemical accelerators"  

E-Print Network (OSTI)

Meetings Chemical Accelerators The phrase "chemical accelerators" is scarcely older than for one or two dozen people grew to include nearly a hundred. Chemical accelerators is a name sug- gested-volt region. Thus chemical accelerators can provide the same type of information for elemen- tary chemical

Zare, Richard N.

386

Radiation protection issues for laser-based accelerators  

Science Journals Connector (OSTI)

......of the laser-based accelerator. THE FLAME PROJECT...high brightness LINAC accelerator of the LNF-Sparc project...aim of an efficient accelerator shielding design is...charged particles, ions, nuclear fragments and delayed...a thin walls of the vacuum chamber at a small angle......

Adolfo Esposito

2011-07-01T23:59:59.000Z

387

New Accelerator Facility for Carbon-Ion Cancer-Therapy  

Science Journals Connector (OSTI)

......rent effect in the vacuum chamber inside the...of the proposed accelerator complex are summarized...displacement 1 mm Vacuum system Ave. pressure...within 1 min. New Accelerator Facility for Carbon...for medical use. Nuclear Physics A 538...European Particle Accelerator Conference, Edinburgh......

Koji Noda; Takuji Furukawa; Takashi Fujisawa; Yoshiyuki Iwata; Tatsuaki Kanai; Mitsutaka Kanazawa; Atsushi Kitagawa; Masataka Komori; Shinichi Minohara; Takeshi Murakami; Masayuki Muramatsu; Shinji Sato; Yuka Takei; Mutsumi Tashiro; Masami Torikoshi; Satoru Yamada; Ken Yusa

2007-03-01T23:59:59.000Z

388

Accelerating classical charges and the equivalence principle  

E-Print Network (OSTI)

We compare the behavior of a charged particle in a gravitational field and empty space. We resolve the apparent conflict between the Lorentz-Dirac equation and Larmor's formula of radiation by noting that the former describes an electron that is itself accelerated by an electromagnetic field. If instead, a hypothetical particle is considered that is accelerated by a non-electromagnetic force, Larmor's formula is found to be consistent with the accelerating particle's equation of motion. We consider the consequences concerning the equivalence principle and find that it is indeed violated if one demands that the same electromagnetic field be present in both the gravitational and accelerating cases; however, if one allows for the external electromagnetic fields to be different, the validity of the equivalence principle is restored. In either case, the basic idea behind the equivalence principle, which leads to a geometrized theory of gravity, remains unaffected.

Viktor T. Toth

2014-04-10T23:59:59.000Z

389

The Muon Accelerator Program  

SciTech Connect

Multi-TeV Muon Colliders and high intensity Neutrino Factories have captured the imagination of the particle physics community. These new types of facility both require an advanced muon source capable of producing O(10{sup 21}) muons per year. The muons must be captured within bunches, and their phase space manipulated so that they fit within the acceptance of an accelerator. In a Neutrino Factory (NF), muons from this 'front end' are accelerated to a few GeV or a few tens of GeV, and then injected into a storage ring with long straight sections. Muon decays in the straight sections produce an intense neutrino beam. In a Muon Collider (MC) the muons must be cooled by a factor O(10{sup 6}) to produce beams that are sufficiently bright to give high luminosity in the collider. Bunches of positive and negative muons are then accelerated to high energy, and injected in opposite directions into a collider ring in which they collide at one or more interaction points. Over the last decade our understanding of the concepts and technologies needed for Muon Colliders and Neutrino Factories has advanced, and it is now believed that, within a few years, with a well focused R&D effort (i) a Neutrino Factory could be proposed, and (ii) enough could be known about the technologies needed for a Muon Collider to assess the feasibility and cost of this new type of facility, and to make a detailed plan for the remaining R&D. Although these next NF and MC steps are achievable, they are also ambitious, and will require an efficient and dedicated organization to accomplish the desired goals with limited resources. The Muon Accelerator Program (MAP) has recently been created to propose and execute this R&D program.

Geer, Steve; /Fermilab; Zisman, Mike; /LBL, Berkeley

2011-08-01T23:59:59.000Z

390

Final Report: Particle Physics Research Program  

SciTech Connect

We describe recent progress in accelerator-based experiments in high-energy particle physics and progress in theoretical investigations in particle physics. We also describe future plans in these areas.

Karchin, Paul E.

2011-09-01T23:59:59.000Z

391

Electron Cloud Effects in Accelerators  

SciTech Connect

Abstract We present a brief summary of various aspects of the electron-cloud effect (ECE) in accelerators. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire ?ECLOUD? series [1?22]. In addition, the proceedings of the various flavors of Particle Accelerator Conferences [23] contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series [24] contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC [25].

Furman, M.A.

2012-11-30T23:59:59.000Z

392

Prospects for all-optical ultrafast muon acceleration  

E-Print Network (OSTI)

A scheme for fast, compact, and controllable acceleration of heavy particles in vacuum has been recently proposed [F. Peano et al., New J. Phys. 10 033028 (2008)], wherein two counterpropagating laser beams with variable frequencies drive a beat-wave structure with variable phase velocity, leading to particle trapping and acceleration. The technique allows for fine control over the energy distribution and the total charge of the accelerated beam, to be obtained via tuning of the frequency variation. Here, the theoretical bases of the acceleration scheme are described, and the possibility of applications to ultrafast muon acceleration and to the prompt extraction of cold-muon beams is discussed.

Peano, F; Mulas, R; Coppa, G; Bingham, R; Silva, L O

2008-01-01T23:59:59.000Z

393

Linear Collider Collaboration Tech Notes  

NLE Websites -- All DOE Office Websites (Extended Search)

0 0 April 2001 Rev.1 July 2003 Guide to LIBXSIF, a Library for Parsing the Extended Standard Input Format of Accelerated Beamlines Peter G. Tenenbaum Stanford Linear Accelerator Center Stanford University Stanford, CA Abstract: We describe LIBXSIF, a standalone library for parsing the Extended Standard Input Format of accelerator beamlines. Included in the description are: documentation of user commands; full description of permitted accelerator elements and their attributes; the construction of beamline lists; the mechanics of adding LIBXSIF to an existing program; and "under the hood" details for users who wish to modify the library or are merely morbidly curious. Guide to LIBXSIF, a Library for Parsing the Extended Standard Input Format of

394

Applications of particle accelerators in medicine  

Science Journals Connector (OSTI)

......cryomodule housing five 5-cell cavities operating at...to the one using LEU fuel with nuclear reactors...the treatment room. Degradation of beam energy implies...the amount of energy degradation required, for a given...is a standing-wave cell-coupled structure operating......

Marco Silari

2011-07-01T23:59:59.000Z

395

LASER ACCELERATION IN VACUUM J.L. Hsu, T. Katsouleas  

E-Print Network (OSTI)

LASER ACCELERATION IN VACUUM J.L. Hsu, T. Katsouleas University of Southern California, Los Angeles electric fields of high-brightness lasers (e.g., up to order TV/cm) to accelerate particles. Unfortunately, as is well known, it is difficult to couple the vacuum field of the laser to particles so as to achieve a net

Wurtele, Jonathan

396

Linear Collider Collaboration Tech Notes  

NLE Websites -- All DOE Office Websites (Extended Search)

6, 27/05/99 6, 27/05/99 Tolerances of Random RF Jitters in X-Band Main Linacs May 27, 1999 Kiyoshi KUBO KEK Tsukuba, Japan Abstract: Tracking simulations have been performed for the main linacs of an X-band linear collider. We discuss the choice of phase of the accelerating field relative to the bunches. The tolerances of the phase and the amplitude errors are studied. Tolerances of Random RF Jitters in X-Band Main Linacs K. Kubo, KEK Abstract Tracking simulations have been performed for main linacs of X-band linear collider. We discuss about choice of the phase of the accelerating field relative to the bunches. The tolerances of the phase and the amplitude errors are studied. 1 INTRODUCTION In order to preserve the low emittance through the main linacs of future linear colliders, various effects

397

Charged relativistic fluids and non-linear electrodynamics  

E-Print Network (OSTI)

The electromagnetic fields in Maxwell's theory satisfy linear equations in the classical vacuum. This is modified in classical non-linear electrodynamic theories. To date there has been little experimental evidence that any of these modified theories are tenable. However with the advent of high-intensity lasers and powerful laboratory magnetic fields this situation may be changing. We argue that an approach involving the self-consistent relativistic motion of a smooth fluid-like distribution of matter (composed of a large number of charged or neutral particles) in an electromagnetic field offers a viable theoretical framework in which to explore the experimental consequences of non-linear electrodynamics. We construct such a model based on the theory of Born and Infeld and suggest that a simple laboratory experiment involving the propagation of light in a static magnetic field could be used to place bounds on the fundamental coupling in that theory. Such a framework has many applications including a new description of the motion of particles in modern accelerators and plasmas as well as phenomena in astrophysical contexts such as in the environment of magnetars, quasars and gamma-ray bursts.

T. Dereli; R. W. Tucker

2010-01-08T23:59:59.000Z

398

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect

Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {micro}m/OD = 325 {micro}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

Thompson, M C; Badakov, H; Rosenzweig, J B; Travish, G; Hogan, M; Ischebeck, R; Kirby, N; Siemann, R; Walz, D; Muggli, P; Scott, A; Yoder, R

2006-08-04T23:59:59.000Z

399

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect

Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}z = 20 {mu}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {mu}m / OD = 325 {mu}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

Thompson, M. C. [Lawrence Livermore National Laboratory, Livermore, California, 90095 (United States); Badakov, H.; Rosenzweig, J. B.; Travis, G. [UCLA Department of Physics and Astronomy, Los Angeles, California, 90095 (United States); Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D. [Stanford Linear Accelerator Center, Stanford, California, 94309 (United States); Muggli, P. [University of Southern California Los Angeles, California, 90089 (United States); Scott, A. [UCSB Department of Physics, Santa Barbara, California, 93106 (United States); Yoder, R. [Manhattan College, Riverdale, New York, 10471 (United States)

2006-11-27T23:59:59.000Z

400

Accelerating Solutions  

NLE Websites -- All DOE Office Websites (Extended Search)

Solutions From vehicles on the road to the energy that powers them, Oak Ridge National Laboratory innovations are advancing American transportation. Oak Ridge National Laboratory is making an impact on everyday America by enhancing transportation choices and quality of life. Through strong collaborative partnerships with industry, ORNL research and development efforts are helping accelerate the deployment of a new generation of energy efficient vehicles powered by domestic, renewable, clean energy. EPA ultra-low sulfur diesel fuel rule ORNL and the National Renewable Energy Laboratory co-led a comprehensive research and test program to determine the effects of diesel fuel sulfur on emissions and emission control (catalyst) technology. In the course of this program, involving

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

COMPASS, the COMmunity Petascale project for Accelerator Science and Simulation, a broad computational accelerator physics  

E-Print Network (OSTI)

80303 2 Fermi National Accelerator Laboratory, Batavia, IL 60510 3 Argonne National Laboratory, Argonne Accelerator Laboratory, Batavia IL, 60510 3 Argonne National Laboratory, Argonne, IL 60439 4 Brookhaven, including colliders for particle physics and nuclear science and light sources and neutron sources

Geddes, Cameron Guy Robinson

402

Accelerating projects  

SciTech Connect

This chapter describes work at ORNL in the period around 1950, when the laboratory was evolving from its original mission of research aimed at producing the atomic bomb, to a new mission, which in many ways was unclear. The research division from Y-12 merged with the laboratory, which gave an increased work force, access to a wide array of equipment, and the opportunity to work on a number of projects related to nuclear propulsion. The first major project was for a nuclear aircraft. From work on this program, a good share of the laboratories work in peaceful application of nuclear energy would spring. A major concern was the development of light weight shielding to protect the crew and materials in such a plane. To do such shielding work, the laboratory employed existing, and new reactors. The original plans called for the transfer of reactor work to Argonne, but because of their own research load, and the needs of the lab, new reactor projects were started at the lab. They included the Low Intensity Test Reactor, the Swimming Pool Reactor, the Bulk Shielding Reactor, the Tower Shielding Facility, and others. The laboratory was able to extend early work on calutrons to accelerator development, pursuing both electrostatic accelerators and cyclotrons. The aircraft project also drove the need for immense quantities of scientific data, with rapid analysis, which resulted the development of divisions aimed at information support and calculational support. The laboratory also expanded its work in the effects of radiation and cells and biological systems, as well as in health physics.

Not Available

1992-01-01T23:59:59.000Z

403

Teleportation of Accelerated Information  

E-Print Network (OSTI)

A theoretical quantum teleportation protocal is suggested to teleport accelerated and non-accelerated information over different classes of accelerated quantum channels. For the accelerated information, it is shown that the fidelity of the teleported state increases as the entanglement of the initial quantum channel increases. However as the difference between the accelerated channel and the accelerated information decreases the fidelity increases. The fidelity of the non accelerated information increases as the entanglement of the initial quantum channel increases, while the accelerations of the quantum channel has a little effect. The possibility of sending quantum information over accelerated quantum channels is much better than sending classical information.

N. Metwally

2012-06-17T23:59:59.000Z

404

Imaging whole Escherichia coli bacteria by using single-particle x-ray diffraction  

Science Journals Connector (OSTI)

...Laboratory, Stanford Linear Accelerator Center, Stanford University...experiment was performed in a vacuum with a pressure of...Suzuki M Ishikawa T ( 2001 ) Nuclear Instr & Methods A 467–468 : 686...Laboratory, Stanford Linear Accelerator Center, Stanford University...

Jianwei Miao; Keith O. Hodgson; Tetsuya Ishikawa; Carolyn A. Larabell; Mark A. LeGros; Yoshinori Nishino

2003-01-01T23:59:59.000Z

405

Fermilab's Accelerator and Research Divisions  

NLE Websites -- All DOE Office Websites (Extended Search)

July 19, 1996 July 19, 1996 Number 14 Fixed-target experimenters not only expect Fermilab's Accelerator and Research Divisions to turn water into wine-they need 10 different vintages. Providing beam to fixed-target experiments presents the challenge of converting high-inten- sity protons into 10 separate beams of varying intensities and particles, from kaons to neu- trinos. The Accelerator Division generates and splits the beam, and then hands the protons off to the Research Division, which converts them into beams of different particles. The process begins with a breath of hydrogen gas. Eventually the hydrogen atoms lose their outer electrons and become a stream of protons-the formation of the beam. Physicists measure two characteristics of the beam: its energy (eV) and its intensity. Intensity

406

Cosmic antifriction and accelerated expansion  

Science Journals Connector (OSTI)

We explain an accelerated expansion of the present Universe, suggested from observations of supernovae of type Ia at high redshift, by introducing an antifrictional force that is self-consistently exerted on the particles of the cosmic substratum. Cosmic antifriction, which is intimately related to “particle production,” is shown to give rise to an effective negative pressure of the cosmic medium. While other explanations for an accelerated expansion (cosmological constant, quintessence) introduce a component of dark energy in addition to “standard” cold dark matter (CDM) we resort to a phenomenological one-component model of CDM with internal self-interactions. We demonstrate how the dynamics of the cold dark matter model with a cosmological constant may be recovered as a special case of cosmic antifriction. We discuss the connection with two-component models and obtain an attractor behavior for the ratio of the energy densities of both components which provides a possible phenomenological solution to the coincidence problem.

Winfried Zimdahl; Dominik J. Schwarz; Alexander B. Balakin; Diego Pavón

2001-08-03T23:59:59.000Z

407

Hamiltonian systems in accelerator physics  

SciTech Connect

General features of the design of annular particle accelerators or storage rings are outlined and the Hamiltonian character of individual-ion motion is indicated. Examples of phase plots are presented, for the motion in one spatial degree of freedom, of an ion subject to a periodic nonlinear focusing force. A canonical transformation describing coupled nonlinear motion also is given, and alternative types of graphical display are suggested for the investigation of long-term stability in such cases. 7 figs.

Laslett, L.J.

1985-06-01T23:59:59.000Z

408

for sequence accelerators  

E-Print Network (OSTI)

Wynn's -algorithm for sequence accelerators using high precision arithmetic Rachel Baumann University of Arizona Wynn's -algorithm for sequence accelerators using high precision arithmetic Rachel Baumann University of Arizona April 17, 2012 #12;Wynn's -algorithm for sequence accelerators using high

Zakharov, Vladimir

409

High-Current Accelerators  

E-Print Network (OSTI)

F i g . 13 F i g . 14 A 48 ACCELERATOR F i g . 25 F i g . 16supply. Extrapolation of accelerator energy and current9 . A-48 high-current accelerator, low-velocity end. Fig.

Lawrence, Ernest O.

1955-01-01T23:59:59.000Z

410

Muon Collider Progress: Accelerators  

SciTech Connect

A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 × 10{sup 34} cm{sup –2}s{sup –1}. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance (“cooling”). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. The Muon Accelerator Program, led by Fermilab and including a number of U.S. national laboratories and universities, has undertaken design and R&D activities aimed toward the eventual construction of a muon collider. Design features of such a facility and the supporting R&D program are described.

Zisman, Michael S.

2011-09-10T23:59:59.000Z

411

Lab announces Venture Acceleration  

NLE Websites -- All DOE Office Websites (Extended Search)

Inc., and ThermaSun Inc. as recipients of awards from the Los Alamos National Security, LLC Venture Acceleration Fund. The Laboratory's Venture Acceleration Fund provides...

412

Chromosome aberrations induced in human lymphocytes by heavy charged particles in track segment mode  

Science Journals Connector (OSTI)

......Regulatoria Nuclear, Av. Del Libertador...to different accelerators and particles...consists of two vacuum chambers linked...passes out of the accelerator tube through a vacuum window of 100...achieved at both accelerators. An example......

M. Di Giorgio; A. A. Edwards; J. E. Moquet; P. Finnon; P. A. Hone; D. C. Lloyd; A. J. Kreiner; J. A. Schuff; M. R. Taja; M. B. Vallerga; F. O. López; A. Burlón; M. E. Debray; A. Valda

2004-01-01T23:59:59.000Z

413

Nonparaxial Mathieu and Weber accelerating beams  

E-Print Network (OSTI)

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 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.

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

2012-10-23T23:59:59.000Z

414

A new relativistic kinematics of accelerated systems  

E-Print Network (OSTI)

We consider transformations between uniformly accelerated systems, assuming that the Clock Hypothesis is false. We use the proper velocity-time description of events rather than the usual space-time description in order to obtain linear transformations. Based on the generalized principle of relativity and the ensuing symmetry, we obtain transformations of Lorentz-type. We predict the existence of a maximal acceleration and time dilation due to acceleration. We also predict a Doppler shift due to acceleration of the source in addition to the shift due to the source's velocity. Based on our results, we explain the W. K\\"{u}ndig experiment, as reanalyzed by Kholmetski \\textit{et al}, and obtain an estimate of the maximal acceleration.

Yaakov Friedman; Yuriy Gofman

2005-09-01T23:59:59.000Z

415

ACCELERATING POLARIZED PROTONS TO HIGH ENERGY.  

SciTech Connect

The Relativistic Heavy Ion Collider (RHIC) is designed to provide collisions of high energy polarized protons for the quest of understanding the proton spin structure. Polarized proton collisions at a beam energy of 100 GeV have been achieved in RHIC since 2001. Recently, polarized proton beam was accelerated to 250 GeV in RHIC for the first time. Unlike accelerating unpolarized protons, the challenge for achieving high energy polarized protons is to fight the various mechanisms in an accelerator that can lead to partial or total polarization loss due to the interaction of the spin vector with the magnetic fields. We report on the progress of the RHIC polarized proton program. We also present the strategies of how to preserve the polarization through the entire acceleration chain, i.e. a 200 MeV linear accelerator, the Booster, the AGS and RHIC.

BAI, M.; AHRENS, L.; ALEKSEEV, I.G.; ALESSI, J.; BEEBE-WANG, J.; BLASKIEWICZ, M.; BRAVAR, A.; BRENNAN, J.M.; BRUNO, D.; BUNCE, G.; ET AL.

2006-10-02T23:59:59.000Z

416

Lab Breakthrough: Fermilab Accelerator Technology | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Fermilab Accelerator Technology Fermilab Accelerator Technology Lab Breakthrough: Fermilab Accelerator Technology May 14, 2012 - 10:51am Addthis At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Michael Hess Michael Hess Former Digital Communications Specialist, Office of Public Affairs Where are these 30,000 particle accelerators? Most of them in medicine and manufacturing fields. They treat cancer, cure inks on cereal boxes, sterilize medical supplies, create better shrink wrap, spot suspicious cargo, clean up dirty drinking water, and help design drugs. Fermi National Accelerator Laboratory scientist Stuart Henderson took some time discuss the role of particle accelerators in basic science,

417

High-brightness H/sup -/ accelerators  

SciTech Connect

Neutral particle beam (NPB) devices based on high-brightness H/sup -/ accelerators are an important component of proposed strategic defense systems. The basic rationale and R and D program are outlined and examples given of the underlying technology thrusts toward advanced systems. Much of the research accomplished in the past year is applicable to accelerator systems in general; some of these activities are discussed.

Jameson, R.A.

1987-01-01T23:59:59.000Z

418

I. ACCELERATION A. Introduction  

E-Print Network (OSTI)

I. ACCELERATION A. Introduction Following cooling and initial bunch compression, the beams must be rapidly accelerated. The acceleration needed for a Higgs collider is probably the most conventional part undertaken. A sequence of linacs would work, but would be expensive. Some form of circulating acceleration

McDonald, Kirk

419

Superconducting Radiofrequency (SRF) Accelerator Cavities  

SciTech Connect

Charlie Reece, an accelerator technology scientist, explains how superconducting radiofrequency accelerator cavities work.

Reece, Charlie

2013-05-03T23:59:59.000Z

420

Superconducting Radiofrequency (SRF) Accelerator Cavities  

ScienceCinema (OSTI)

Charlie Reece, an accelerator technology scientist, explains how superconducting radiofrequency accelerator cavities work.

Reece, Charlie

2014-05-22T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Perpendicular ion acceleration in whistler turbulence  

SciTech Connect

Whistler turbulence is an important contributor to solar wind turbulence dissipation. This turbulence contains obliquely propagating whistler waves at electron scales, and these waves have electrostatic components perpendicular to the mean magnetic field. In this paper, a full kinetic, two-dimensional particle-in-cell simulation shows that whistler turbulence can accelerate ions in the direction perpendicular to the mean magnetic field. When the ions pass through wave-particle resonances region in the phase space during their cyclotron motion, the ions are effectively accelerated in the perpendicular direction. The simulation results suggest that whistler turbulence contributes to the perpendicular heating of ions observed in the solar wind.

Saito, S. [Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8601 (Japan)] [Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8601 (Japan); Nariyuki, Y. [Faculty of Human Development, University of Toyama, 3190, Toyama 930-8555 (Japan)] [Faculty of Human Development, University of Toyama, 3190, Toyama 930-8555 (Japan)

2014-04-15T23:59:59.000Z

422

The Particle Adventure | How do we experiment with tiny particles? | What  

NLE Websites -- All DOE Office Websites (Extended Search)

What makes particles go in a circle? What makes particles go in a circle? What makes particles go in a circle? To keep any object going in a circle, there needs to be a constant force on that object towards the center of the circle. In a circular accelerator, an electric field makes the charged particle accelerate, while large magnets provide the necessary inward force to bend the particle's path in a circle. (In the image to the left, the particle's velocity is represented by the white arrow, while the inward force supplied by the magnet is the yellow arrow.) The presence of a magnetic field does not add or subtract energy from the particles. The magnetic field only bends the particles' paths along the arc of the accelerator. Magnets are also used to direct charged particle beams toward targets and to "focus" the beams, just as optical lenses focus light.

423

E-Print Network 3.0 - accelerating polarized beams Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

polarized beams Search Powered by Explorit Topic List Advanced Search Sample search results for: accelerating polarized beams Page: << < 1 2 3 4 5 > >> 1 Linear Collider...

424

Krylov Subspace Accelerated Algebraic Multigrid for Mimetic Finite Differences on GPUs.  

E-Print Network (OSTI)

?? The topic of this thesis is GPU accelerated sparse linear algebra for subsurface reservoir modeling. Numerical techniques for reservoir sim- ulations are described and… (more)

Lønsethagen, Simen Andreas Andreassen

2012-01-01T23:59:59.000Z

425

Fermilab | Illinois Accelerator Research Center | Illinois Accelerator  

NLE Websites -- All DOE Office Websites (Extended Search)

photo: IARC photo: IARC As envisioned, the Illinois Accelerator Research Center will provide approximately 83,000 square feet of technical, office and classroom space for scientists and industrial partners. The Illinois Accelerator Research Center (IARC) is a new accelerator research facility being built at Fermi National Accelerator Laboratory. At the Illinois Accelerator Research Center, scientists and engineers from Fermilab, Argonne and Illinois universities will work side by side with industrial partners to research and develop breakthroughs in accelerator science and translate them into applications for the nation's health, wealth and security. Located on the Fermilab campus this 83,000 square foot, state-of-the-art facility will house offices, technical and educational space to study

426

Petawatt pulsed-power accelerator  

DOE Patents (OSTI)

A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

Stygar, William A. (Albuquerque, NM); Cuneo, Michael E. (Albuquerque, NM); Headley, Daniel I. (Albuquerque, NM); Ives, Harry C. (Albuquerque, NM); Ives, legal representative; Berry Cottrell (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Olson, Craig L. (Albuquerque, NM); Porter, John L. (Sandia Park, NM); Wagoner; Tim C. (Albuquerque, NM)

2010-03-16T23:59:59.000Z

427

Some Particle Properties  

NLE Websites -- All DOE Office Websites (Extended Search)

Particle Properties Particle Properties An Article Written Originally for Midlevel Teachers Back A particle, increasing its speed because of some force acting on it, gains energy of motion. An electron (negatively charged) gains one electron volt (eV) of energy in accelerating through a vacuum from the negative end to the positive end of a one-volt battery. The one eV of energy is given up to other particles as the electron crashes into the positive end. A proton (positively charged) traveling from positive to negative pole through the vacuum would also gain one eV of energy and give it up in its collision with particles in the negative end. This proton collision is similar to the proton beam collision with a target at Fermilab, but at Fermilab the proton energy is much greater.

428

Laser-PlasmaWakefield Acceleration with Higher Order Laser Modes  

E-Print Network (OSTI)

Design considerations for a laser-plasma linear collider,"E.Esarey, and W.P.Leemans, "Free-electron laser driven bythe LBNL laser-plasma accelerator," in Proc. Adv. Acc. Con.

Geddes, C.G.R.

2011-01-01T23:59:59.000Z

429

Proceedings of the first international workshop on accelerator alignment  

SciTech Connect

This report contains papers on the following accelerator topics: current alignment topics; toolboxes: instrumentation, software, and methods; fiducialization of conventional magnets; fiducialization of superconducting magnets; and next generation linear colliders.

Not Available

1990-10-01T23:59:59.000Z

430

Acceleration and vortex filaments in turbulence  

E-Print Network (OSTI)

We report recent results from a high resolution numerical study of fluid particles transported by a fully developed turbulent flow. Single particle trajectories were followed for a time range spanning more than three decades, from less than a tenth of the Kolmogorov time-scale up to one large-eddy turnover time. We present some results concerning acceleration statistics and the statistics of trapping by vortex filaments.

F. Toschi; L. Biferale; G. Boffetta; A. Celani; B. J. Devenish; A. Lanotte

2005-01-23T23:59:59.000Z

431

Argonne cranks up new heavy-ion accelerator  

Science Journals Connector (OSTI)

Argonne cranks up new heavy-ion accelerator ... Dedication ceremonies at Argonne National Laboratory last week celebrated completion of the Argonne Tandem Linear Accelerator System (ATLAS), the world's first superconducting accelerator for heavy ions. ... "We expect ATLAS to permit scientists to study certain aspects of nuclear structure and interactions more closely than ever before," says Argonne nuclear physicist Lowell M. Bollinger, manager of the ATLAS project. ...

1985-06-10T23:59:59.000Z

432

Cosmic Acceleration and Anisotropic models with Magnetic field  

E-Print Network (OSTI)

Plane symmetric cosmological models are investigated with or without any dark energy components in the field equations. Keeping an eye on the recent observational constraints concerning the accelerating phase of expansion of the universe, the role of magnetic field is assessed. The presence of magnetic field can favour an accelerating model even if we take a linear relationship between the directional Hubble parameters.

S. K. Tripathy; K. L. Mahanta

2014-07-27T23:59:59.000Z

433

Argonne Accelerator Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

Research and Development Research and Development Click to download a PDF version of this document. PDF Focus Research Areas Fundamental Accelerator Physics: Theory Importance Accelerator physics research is normally associated with specific accelerator projects. As a scientific discipline, however, it is useful to study fundamental accelerator phenomena decoupled, as much as possible, from specific project aspects. Pursuit of fundamental accelerator physics in this sense has contributed significantly to the advance of the accelerator physics knowledgebase during the last several decades, clarifying the limitations and suggesting ways to overcome those limitations. Such basic research tends to be discouraged in a project-driven environment. For sustained and significant progress in

434

Accelerator and Fusion Research Division  

NLE Websites -- All DOE Office Websites (Extended Search)

Outreach and Diversity Highlights Safety Other Sites and Labs Intramural Outreach and Diversity Highlights Safety Other Sites and Labs Intramural Historical photo of Laboratory founder and cyclotron inventor Ernest Orlando Lawrence at his desk OUR SCIENTIFIC PROGRAMS Accelerator Physics for the ALS Center for Beam Physics LOASIS Laboratory Fusion Science and Ion Beam Technology Superconducting Magnets Free Electron Laser R&D News: AFRD's Jean-Luc Vay and former AFRD scientist Kwang-Je Kim share the US Particle Accelerator School Prize. Andre Anders places two articles among the year's top 30 in the Journal of Applied Physics. AFRD personnel win an R&D 100 in a joint project with industry; the laser at the heart of BELLA sets a world record for laser power. Employees: Safety tips regarding the mountain lion are available. The results from our two most recent Self-Assessment Focus Groups are up, covering emergency preparedness and ergonomics while working offsite.

435

Kinematic moment invariants for linear Hamiltonian systems  

Science Journals Connector (OSTI)

Quadratic moments of a particle distribution being transported through a linear Hamiltonian system are considered. A complete set of kinematic invariants made out of these moments are constructed leading to the discovery of new invariants.

Filippo Neri and Govindan Rangarajan

1990-03-05T23:59:59.000Z

436

Direct laser acceleration of electrons in free-space  

E-Print Network (OSTI)

Compact laser-driven accelerators are versatile and powerful tools of unarguable relevance on societal grounds for the diverse purposes of science, health, security, and technology because they bring enormous practicality to state-of-the-art achievements of conventional radio-frequency accelerators. Current benchmarking laser-based technologies rely on a medium to assist the light-matter interaction, which impose material limitations or strongly inhomogeneous fields. The advent of few cycle ultra-intense radially polarized lasers has materialized an extensively studied novel accelerator that adopts the simplest form of laser acceleration and is unique in requiring no medium to achieve strong longitudinal energy transfer directly from laser to particle. Here we present the first observation of direct longitudinal laser acceleration of non-relativistic electrons that undergo highly-directional multi-GeV/m accelerating gradients. This demonstration opens a new frontier for direct laser-driven particle accelerati...

Carbajo, Sergio; Wong, Liang Jie; Miller, R J Dwayne; Kärtner, Franz X

2015-01-01T23:59:59.000Z

437

E-Print Network 3.0 - accelerator neutron source Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

driven by a powerful particle accelerator. This intense neutron source... . In subcritical systems driven by an intense external source of neutrons - in ADS. An external...

438

E-Print Network 3.0 - acceleration foran electron Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics and Fusion ; Physics 10 The Application of Radiation and Particle Beams from Laser Plasma Wakefield Accelerators to Oncology Summary: to recent improvements in...

439

E-Print Network 3.0 - accelerator energy constraints Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Christian, Eric - Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center Collection: Physics 2 Particle acceleration in solar flares: observations versus...

440

E-Print Network 3.0 - accelerator applications university Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

university Page: << < 1 2 3 4 5 > >> 1 The Application of Radiation and Particle Beams from Laser Plasma Wakefield Accelerators to Oncology Summary: The Application of...

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

E-Print Network 3.0 - athens tandem accelerator Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

results for: athens tandem accelerator Page: << < 1 2 3 4 5 > >> 1 Workshop on Thermonuclear Reaction Rates for Astrophysics Applications Summary: , particle physics, neutrino...

442

Jefferson Lab Fall Lecture: Exploring Our World With Particle...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fall Lecture: Exploring Our World With Particle Accelerators NEWPORT NEWS, Va., Nov. 9, 2010 - Jefferson Lab's 2010 Fall Science Lecture Series concludes on Tuesday, Nov. 23, with...

443

Recirculating Linac Accelerators For Future Muon Facilities  

SciTech Connect

Neutrino Factories (NF) and Muon Colliders (MC) require rapid acceleration of shortlived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses superconducting RF structures can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity. A new concept of rapidly changing the strength of the RLA focusing quadrupoles as the muons gain energy is being developed to increase the number of passes that each muon will make in the RF cavities, leading to greater cost effectiveness. We discuss the optics and technical requirements for RLA designs, using RF cavities capable of simultaneous acceleration of both m+ and m- species. The design will include the optics for the multi-pass linac and droplet-shaped return arcs.

Yves Roblin, Alex Bogacz, Vasiliy Morozov, Kevin Beard

2012-04-01T23:59:59.000Z

444

Testing General Relativity With Laser Accelerated Electron Beams  

E-Print Network (OSTI)

Electron accelerations of the order of $10^{21} g$ 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.

L. Á. Gergely; T. Harko

2012-07-16T23:59:59.000Z

445

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)

2012-07-09T23:59:59.000Z

446

LARGE-APERTURE D- ACCELERATORS  

E-Print Network (OSTI)

Vignetted current profile at accelerator entrance aperture 'LARGE-APERTURE D" ACCELERATORS* 0. A. Anderson" " Lawrencen i a 9-1720 Abstract Accelerator designs are described for

Anderson, O.A.

2010-01-01T23:59:59.000Z

447

Beam Dynamics for Induction Accelerators  

E-Print Network (OSTI)

Dynamics for Induction Accelerators Edward P. Lee Lawrencea natural candidate accelerator for a heavy ion fusion (HIF)words: Fusion, Induction, Accelerators, Dynamics This work

Lee, E.P.

2014-01-01T23:59:59.000Z

448

Monte Carlo simulations for the shielding of the future high-intensity accelerator facility fair at GSI  

Science Journals Connector (OSTI)

......the universal linear accelerator, UNILAC, the heavy-ion...expands on the present accelerator system at the GSI...beams are produced in nuclear reactions induced by...PROTON AND HEAVY-ION ACCELERATOR During the acceleration...certain flight path in the vacuum. The wall thickness......

T. Radon; F. Gutermuth; G. Fehrenbacher

2005-12-20T23:59:59.000Z

449

From Autos to Accelerators | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

From Autos to Accelerators From Autos to Accelerators From Autos to Accelerators September 7, 2010 - 6:36pm Addthis Kathryn Grim Physicist Terry Grimm has a vision for Lansing, Michigan. In a town haunted by the remains of fallen automobile plants, his company and others like it are hiring workers to put their car-manufacturing skills toward building particle accelerators. "People question whether manufacturing is going to go away in this country," Grimm said. "That's not the case. There's enough high-tech industry that needs it. We need the same expertise that the auto industry required." Fermilab used funds from the American Recovery and Reinvestment Act to hire Grimm's company, Niowave Inc., to build superconducting radio-frequency cavities in cooperation with Indiana-based Roark Welding & Engineering Co.

450

Dark Energy and the Accelerating Universe  

E-Print Network (OSTI)

The discovery ten years ago that the expansion of the Universe is accelerating put in place the last major building block of the present cosmological model, in which the Universe is composed of 4% baryons, 20% dark matter, and 76% dark energy. At the same time, it posed one of the most profound mysteries in all of science, with deep connections to both astrophysics and particle physics. Cosmic acceleration could arise from the repulsive gravity of dark energy -- for example, the quantum energy of the vacuum -- or it may signal that General Relativity breaks down on cosmological scales and must be replaced. We review the present observational evidence for cosmic acceleration and what it has revealed about dark energy, discuss the various theoretical ideas that have been proposed to explain acceleration, and describe the key observational probes that will shed light on this enigma in the coming years.

Joshua Frieman; Michael Turner; Dragan Huterer

2008-03-07T23:59:59.000Z

451

Dark Energy and the Accelerating Universe  

E-Print Network (OSTI)

The discovery ten years ago that the expansion of the Universe is accelerating put in place the last major building block of the present cosmological model, in which the Universe is composed of 4% baryons, 20% dark matter, and 76% dark energy. At the same time, it posed one of the most profound mysteries in all of science, with deep connections to both astrophysics and particle physics. Cosmic acceleration could arise from the repulsive gravity of dark energy -- for example, the quantum energy of the vacuum -- or it may signal that General Relativity breaks down on cosmological scales and must be replaced. We review the present observational evidence for cosmic acceleration and what it has revealed about dark energy, discuss the various theoretical ideas that have been proposed to explain acceleration, and describe the key observational probes that will shed light on this enigma in the coming years.

Frieman, Joshua; Huterer, Dragan

2008-01-01T23:59:59.000Z

452

E-Print Network 3.0 - accelerator beam dumps Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

RECOVERY LINACS G.H. Hoffstaetter Summary: (ERLs) accelerate high-current particle beams to high energy in a linac. These are then used in x... of particles. Only with such...

453

Beyond the Desert 2002, Accelerator, Non--Accelerator and Space Approaches in the New Millenium  

E-Print Network (OSTI)

The third conference on particle physics beyond the Standard Model (BEYOND THE DESERT'02 - Accelerator, Non-accelerator and Space Approaches) was held during 2--7 June, 2002 at the Finish town of Oulu, almost at the northern Arctic Circle. It was the first of the BEYOND conference series held outside Germany (CERN Courier March 2003, pp. 29-30). Traditionally the Scientific Programme of BEYOND conferences, brought into life in 1997 (see CERN Courier, November 1997, pp.16-18), covers almost all topics of modern particle physics (see contents).

H. V. Klapdor Kleingrothaus

2004-04-06T23:59:59.000Z

454

PAIRED ACCELERATED FRAMES: THE PERFECT INTERFEROMETER WITH EVERYWHERE SMOOTH WAVE AMPLITUDES \\Lambda  

E-Print Network (OSTI)

PAIRED ACCELERATED FRAMES: THE PERFECT INTERFEROMETER WITH EVERYWHERE SMOOTH WAVE AMPLITUDES In the absence of gravitation the distinguishing feature of any linearly and uniformly accelerated frame event horizons relative to each of the two frames. This acceleration­ induced partitioning of spacetime

Gerlach, Ulrich

455

Linear Collider Collaboration Tech Notes LCC-0104  

NLE Websites -- All DOE Office Websites (Extended Search)

4 4 October 2002 Beamstrahlung Photon Load on the TESLA Extraction Septum Blade Andrei Seryi Stanford Linear Accelerator Center Stanford, CA 94309, USA Abstract: This note describes work performed in the framework of the International Linear Collider Technical Review Committee [1] to estimate the power load on the TESLA extraction septum blade due to beamstrahlung photons. It is shown, that under realistic conditions the photon load can be several orders of magnitude higher than what was estimated in the TESLA TDR [2] for the ideal Gaussian beams, potentially representing a serious limitation of the current design. Beamstrahlung Photon Load on the TESLA Extraction Septum Blade ANDREI SERYI STANFORD LINEAR

456

Combined gravitational and electromagnetic self-force on charged particles in electrovac spacetimes  

E-Print Network (OSTI)

We consider the self-force on a charged particle moving in a curved spacetime with a background electromagnetic field, extending previous studies to situations in which gravitational and electromagnetic perturbations are comparable. The formal expression $f^{ret}_\\alpha$ for the self-force on a particle, written in terms of the retarded perturbed fields, is divergent, and a renormalization is needed to find the particle's acceleration at linear order in its mass $m$ and charge $e$. We assume that, as in previous work in a Lorenz gauge, the renormalization for accelerated motion comprises an angle average and mass renormalization. Using the short distance expansion of the perturbed electromagnetic and gravitational fields, we show that the renormalization is equivalent to that obtained from a mode sum regularization in which one subtracts from the expression for the self-force in terms of the retarded fields a singular part field comprising only the leading and subleading terms in the mode sum. The most striking part of our result, arising from a remarkable cancellation, is that the renormalization involves no mixing of electromagnetic and gravitational fields. In particular, the renormalized mass is obtained by subtracting (1) the purely electromagnetic contribution from a point charge moving along an accelerated trajectory and (2) the purely gravitational contribution from a point mass moving along the same trajectory. In a mode-sum regularization, the same cancellation implies that the required regularization parameters are sums of their purely electromagnetic and gravitational values.

Thomas M. Linz; John L. Friedman; Alan G. Wiseman

2014-06-19T23:59:59.000Z

457

Beam dynamics in accelerators for medical applications: from calculations to machine performance  

E-Print Network (OSTI)

Beam dynamics in accelerators for medical applications: from calculations to machine performance S, z', W, RF-phase) at each time-moment for each particle in the accelerating bunch use cylindrical, Novosibirsk, Russian Federation #12;Main results of calculations 6 ...transverse beam size during acceleration

458

SOLVING BY PARALLEL COMPUTATION THE POISSON PROBLEM FOR HIGH INTENSITY BEAMS IN CIRCULAR ACCELERATORS.  

SciTech Connect

Simulation of high intensity accelerators leads to the solution of the Poisson Equation, to calculate space charge forces in the presence of acceleration chamber walls. We reduced the problem to ''two-and-a-half'' dimensions for long particle bunches, characteristic of large circular accelerators, and applied the results to the tracking code Orbit.

LUCCIO,A.U.; DIMPERIO,N.L.; SAMULYAK,R.; BEEB-WANG,J.

2001-06-18T23:59:59.000Z

459

A monolithic relativistic electron beam source based on a dielectric laser accelerator structure  

SciTech Connect

Work towards a monolithic device capable of producing relativistic particle beams within a cubic-centimeter is detailed. We will discuss the Micro-Accelerator Platform (MAP), an optical laser powered dielectric accelerator as the main building block of this chip-scale source along with a field enhanced emitter and a region for sub-relativistic acceleration.

McNeur, Josh; Carranza, Nestor; Travish, Gil; Yin Hairong; Yoder, Rodney [UCLA Dept. of Physics and Astronomy, Los Angeles, CA 90095 (United States); College of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); Manhattanville College, Physics Dept., 2900 Purchase St., Purchase, NY 10577 (United States)

2012-12-21T23:59:59.000Z

460

SLAC low emittance accelerator test facility  

SciTech Connect

SLAC is proposing to build a new Accelerator Test Facility (ATF) capable of producing a 50 MeV electron beam with an extremely low geometric tranverse emittance (1.5 x 10/sup -10/ rad.m) for the purpose of testing new methods of acceleration. The low emittance will be achieved by assembling a linear accelerator using one standard SLAC three-meter section and a 400 kV electron gun with a very small photocathode (40 microns in diameter). The photocathode will be illuminated from the back by short bursts (on the order of 6 ps) of visible laser light which will produce bunches of about 10/sup 5/ electrons. Higher currents could be obtained by illuminating the cathode from the front. The gun will be mounted directly against the accelerator section. Calculations show that in the absence of an rf buncher, injection of these 400 keV small radius electron bunches roughly 30/sup 0/ ahead of crest produces negligible transverse emittance growth due to radial rf forces. Acceleration of the electrons up to 50 MeV followed by collimation, energy slits and focusing will provide a 3.2 mm long waist of under 1.5 ..mu..m in diameter where laser acceleration and other techniques can be tested.

Loew, G.A.; Miller, R.H.; Sinclair, C.K.

1986-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Particle Astrophysics  

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Particle Astrophysics Particle Astrophysics Understanding discoveries at the Energy, Intensity, and Cosmic Frontiers Get Expertise Rajan Gupta (505) 667-7664 Email Bruce Carlsten...

462

BNL | Accelerator Test Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerator Test Facility Accelerator Test Facility Home Core Capabilities Photoinjector S-Band Linac Laser Systems CO2 Laser Nd:Yag Laser Beamlines Beamline Simulation Data Beamline Parameters Beam Diagnostics Detectors Beam Schedule Operations Resources Fact Sheet (.pdf) Image Library Upgrade Proposal (.pdf) Publications ES&H Experiment Start-up ATF Handbook Laser Safety Collider-Accelerator Dept. C-AD ES&H Resources Staff Users' Place Apply for Access ATF photo ATF photo ATF photo ATF photo ATF photo A user facility for advanced accelerator research The Brookhaven Accelerator Test Facility (ATF) is a proposal driven, steering committee reviewed facility that provides users with high-brightness electron- and laser-beams. The ATF pioneered the concept of a user facility for studying complex properties of modern accelerators and

463

Argonne Accelerator Institute  

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Welcome Welcome In 2006, Argonne laboratory director Robert Rosner formed the AAI as a focal point for accelerator initiatives. The institute works to utilize Argonne's extensive accelerator resources, to enhance existing facilities, to determine the future of accelerator development and construction, and to oversee a dynamic and acclaimed accelerator physics portfolio. I invite you to look around the content of this web site. Accelerators at Argonne describes our rich heritage in this field, particularly with respect to the development and support of user facilities. Initiatives describes the things we are hoping to do, and Research & Development discusses our research portfolio. If you are a graduate or undergraduate student wishing to pursue a career in accelerator science or technology, please see Educational

464

Argonne Accelerator Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

The Argonne Accelerator History Document Collection The Argonne Accelerator History Document Collection The Argonne Accelerator Institute (AAI) has established a special collection of archived documents which describe notable Argonne accelerator work of the past 50 years. A list of such Argonne Accelerator Projects is given below. Each project is described briefly, with links to archived documents in this collection. This collection includes important Argonne accelerator documents which may have become difficult to locate, as well as ones which have broad scope. In keeping with its historical purpose, this collection only covers work done 10 or more years ago. Many of the listed documents are available online. We hope to make more of them available online in the future. [For several of the projects, interesting additional online documents can be found by

465

Uniformly accelerated black holes  

Science Journals Connector (OSTI)

The static and stationary C metric are examined in a generic framework and their interpretations studied in some detail, especially those with two event horizons, one for the black hole and another for the acceleration. We find that (i) the spacetime of an accelerated static black hole is plagued by either conical singularities or a lack of smoothness and compactness of the black hole horizon, (ii) by using standard black hole thermodynamics we show that accelerated black holes have a higher Hawking temperature than Unruh temperature of the accelerated frame, and (iii) the usual upper bound on the product of the mass and acceleration parameters (<1/27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.

Patricio S. Letelier and Samuel R. Oliveira

2001-08-24T23:59:59.000Z

466

Ion Acceleration by Short Chirped Laser Pulses  

E-Print Network (OSTI)

Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltán

2015-01-01T23:59:59.000Z

467

Cosmic Accelerators: Engines of the Extreme Universe  

SciTech Connect

The universe is home to numerous exotic and beautiful phenomena, some of which can generate almost inconceivable amounts of energy. While the night sky appears calm, it is populated by colossal explosions, jets from supermassive black holes, rapidly rotating neutron stars, and shock waves of gas moving at supersonic speeds. These accelerators in the sky boost particles to energies far beyond those we can produce on earth. New types of telescopes, including the Fermi Gamma-ray Space Telescope orbiting in space, are now discovering a host of new and more powerful accelerators. Please come and see how these observations are revising our picture of the most energetic phenomena in the universe.

Funk, Stefan

2009-06-23T23:59:59.000Z

468

Optically pulsed electron accelerator  

DOE Patents (OSTI)

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, J.S.; Sheffield, R.L.

1985-05-20T23:59:59.000Z

469

Optically pulsed electron accelerator  

DOE Patents (OSTI)

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, John S. (Los Alamos, NM); Sheffield, Richard L. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

470

Effect of plasma inhomogeneity on plasma wakefield acceleration driven by long bunches  

SciTech Connect

Effects of plasma inhomogeneity on self-modulating proton bunches and accelerated electrons were studied numerically. The main effect is the change of the wakefield wavelength which results in phase shifts and loss of accelerated particles. This effect imposes severe constraints on density uniformity in plasma wakefield accelerators driven by long particle bunches. The transverse two stream instability that transforms the long bunch into a train of micro-bunches is less sensitive to density inhomogeneity than are the accelerated particles. The bunch freely passes through increased density regions and interacts with reduced density regions.

Lotov, K. V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Pukhov, A. [Institut fuer Theoretische Physik I, Heinrich-Heine-Universitaet Duesseldorf, 40225 Duesseldorf (Germany); Caldwell, A. [Max-Planck-Institut fuer Physik, 80805 Muenchen (Germany)

2013-01-15T23:59:59.000Z

471

A world of hope through accelerator-based science and technologies.  

E-Print Network (OSTI)

a 6-MV Tandem Accelerator. Particle beams delivered by the accelerator are used for low energy nuclear nuclear reactions with various solid targets. #12;Particle therapy PROGRAMME #12;iThemba LABS is the only radionuclides, radiopharmaceuticals for nuclear medicine and mainstream radiopharmaceuticals for positron

Wagner, Stephan

472

Accelerated Testing Validation  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Accelerated Testing Validation Rangachary Mukundan (PI), Rodney Borup, John Davey, Roger Lujan Los Alamos National Laboratory Adam Z. Weber Lawrence Berkeley National Laboratory...

473

Market Acceleration (Fact Sheet)  

SciTech Connect

The fact sheet summarizes the goals and activities of the DOE Solar Energy Technologies Program efforts within its market acceleration subprogram.

Not Available

2010-09-01T23:59:59.000Z

474

Accelerated Molecular Dynamics Methods  

Energy.gov (U.S. Department of Energy (DOE))

This presentation on Accelerated Molecular Dynamics Methods was given at the DOE Theory Focus Session on Hydrogen Storage Materials on May 18, 2006.

475

Accelerator Test Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

Director ATF, Accelerator External program committee W. Leemans, Chair M. Woodle Engineer Mechanical M. Montemagno Engineer Electrical I. Pogorelsky, Physicist, Laser P. Jacob...

476

DOE - Office of Legacy Management -- Stanford Linear Accelerator...  

Office of Legacy Management (LM)

by past operations with volatile organic compounds, polychloronated biphenyls, petroleum hydrocarbons, lead, and other metals. Site cleanup is scheduled for completion in...

477

On Theories for Stochastic Acceleration in the Solar Wind  

Science Journals Connector (OSTI)

The suprathermal tails on the distribution functions of ions in the solar wind are observed to have a common spectral shape in many different circumstances: a power law in particle speed with spectral index of –5. Three possible approaches for explaining these observations are considered: (1) the acceleration mechanism of Fisk & Gloeckler in which energy is redistributed from a core particle population into the suprathermal tail; (2) traditional stochastic acceleration in which particles are accelerated by damping turbulence; and (3) the statistical approach introduced by Schwadron et al. in which the –5 spectrum is formed by averaging over individual spectra. The acceleration mechanism of Fisk & Gloeckler has advantages: (1) it appears to occur in conditions that are readily satisfied: compressive turbulence that is thermally isolated (no large-scale spatial gradients), with a core distribution of particles with a sharp initial cutoff in particle speed, above which particles can spatially diffuse; and (2) it yields spectra that are consistent with observations. Traditional stochastic acceleration has the disadvantage that it is unlikely to yield spectral shapes consistent with observations, and the spectra are dependent upon the plasma conditions and thus unlikely to be the same in different circumstances. The statistical approach of Schwadron et al. can yield the –5 spectrum and is consistent with the results of Fisk & Gloeckler when the assumed distribution functions for individual events and the averaging technique are taken to be compatible with the assumptions and averaging in Fisk & Gloeckler.

L. A. Fisk; G. Gloeckler; N. A. Schwadron

2010-01-01T23:59:59.000Z

478

Slow wave structures using twisted waveguides for charged particle applications  

DOE Patents (OSTI)

A rapidly twisted electromagnetic accelerating structure includes a waveguide body having a central axis, one or more helical channels defined by the body and disposed around a substantially linear central axial channel, with central portions of the helical channels merging with the linear central axial channel. The structure propagates electromagnetic waves in the helical channels which support particle beam acceleration in the central axial channel at a phase velocity equal to or slower than the speed of light in free space. Since there is no variation in the shape of the transversal cross-section along the axis of the structure, inexpensive mechanical fabrication processes can be used to form the structure, such as extrusion, casting or injection molding. Also, because the field and frequency of the resonant mode depend on the whole structure rather than on dimensional tolerances of individual cells, no tuning of individual cells is needed. Accordingly, the overall operating frequency may be varied with a tuning/phase shifting device located outside the resonant waveguide structure.

Kang, Yoon W.; Fathy, Aly E.; Wilson, Joshua L.

2012-12-11T23:59:59.000Z

479

Field Emission in CEBAF's SRF Cavities and Implications for Future Accelerators  

SciTech Connect

Field emission is one of the key issues in superconducting RF for particle accelerators. When present, it limits operating gradient directly or via induced heat load at 2K. In order to minimize particulate contamination of and thus field emission in the CEBAF SRF cavities during assembly, a cold ceramic RF window was placed very close to the accelerating cavity proper. As an unintended consequence of this, the window is charged by field-emitted electrons, making it possible to monitor and model field emission in the CEBAF cavities since in-tunnel operation began. From January 30, 1995, through February 10, 2003, there were 64 instances of spontaneous onset or change in cavity field emission with a drop in usable gradient averaging 1.4 ({sigma} 0.8) MV/m at each event. Fractional loss averaged 0.18 ({sigma} 0.12) of pre-event gradient. This event count corresponds to 2.4 events per century per cavity, or 8 per year in CEBAF. It is hypothesized that changes in field emission are due to adsorbed gas accumulation. The possible implications of this and other observations for the International Linear Collider (ILC) and other future accelerators will be discussed.

Jay Benesch

2006-02-15T23:59:59.000Z

480

13S C I D A C R E V I E W S U M M E R 2 0 0 9 W W W . S C I D A C R E V I E W . O R G LASER P LASM A PART ICLE ACCELERATORS  

E-Print Network (OSTI)

A PART ICLE ACCELERATORS Compared to conventional particle accelerators, plasmas can sustain accelerating 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

Knowles, David William

Note: This page contains sample records for the topic "linear particle accelerator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams  

SciTech Connect

Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

Siemann, R.H.; /SLAC

2011-10-24T23:59:59.000Z

482

Acceleration Worksheet 8/24/2011 ACCELERATION WORKSHEET  

E-Print Network (OSTI)

Acceleration Worksheet 8/24/2011 ACCELERATION WORKSHEET College of Arts and Sciences Name _____________ TO _____________ month/year month/year II. I meet the requirements for acceleration under [fill out either a) or b;Acceleration Worksheet 8/24/2011 Acceleration 2011-2012 Courses of Study The faculty of the college desires

Davis, H. Floyd

483

NERSC and CRD Help Decipher Science from Compact Accelerator Simulations -  

NLE Websites -- All DOE Office Websites (Extended Search)

and CRD Help and CRD Help Decipher Science from Compact Accelerator Simulations NERSC and CRD Help Decipher Science from Compact Accelerator Simulations May 26, 2009 3D Particle Surfing : Electrons are moving from left to right in this LOASIS experiment. The blue shells show the plasma wake, while bunches of surfing electrons are shown as green and yellow. Green reveals low-energy particles, and yellow shows high-energy. The simulation was conducted in the VORPAL framework, and visualized with VisIt and VizSchema. Scientists use many different tools to understand the universe. While telescopes offer valuable insights about interactions between stars, planets and galaxies; particle accelerators give researchers a better understanding of the basic particles that make up these structures, as well

484

Accelerator R and D task force presentation - m white  

NLE Websites -- All DOE Office Websites (Extended Search)

DOE DOE Accelerator R&D Task Force Charge Presented at the AAI Meeting, 11/29/11 Marion White mwhite@aps.anl.gov Rod Gerig - Context (1)  "The Committee understands that powerful new accelerator technologies created for basic science and developed by industry will produce particle accelerators with the potential