Powered by Deep Web Technologies
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.


1

LINEAR ACCELERATOR  

DOE Patents (OSTI)

Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

Christofilos, N.C.; Polk, I.J.

1959-02-17T23:59:59.000Z

2

PARTICLE ACCELERATOR  

DOE Patents (OSTI)

A fixed-field alternating gradient accelerator for simultaneous acceleration of two particle beams in opposite directions is described. (T.R.H.)

Ohkawa, T.

1959-06-01T23:59:59.000Z

3

PARTICLE ACCELERATOR  

DOE Patents (OSTI)

ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

Teng, L.C.

1960-01-19T23:59:59.000Z

4

Second order particle motion equations and linear chromaticity calculation in accelerator rings  

SciTech Connect

The first part of this note presents a thorough study on the second order particle motion equations, both in continuous field and in hard edges, with emphasis put on the latter. Having quite general conditions and strict mathematical treatments, it provides a sound ground from which many problems can be solved without fear of being misled. Then the linear CHR calculation is inspected, the first step being a general analytical expression of the transverse oscillation phase increment due to a small disturbance. The expression for the CHR is then readily obtained since tune is the transverse oscillation number per turn and the CHR is the linear dependence of the tune on particle energy/momentum deviation. The last part gives the formulae for practical CHR calculation, which are general enough to include almost all the magnet types commonly used in various accelerator rings and are simpler than can be found elsewhere.

Liu, R.Z.

1984-01-01T23:59:59.000Z

5

HEAVY ION LINEAR ACCELERATOR  

DOE Patents (OSTI)

A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.

Van Atta, C.M.; Beringer, R.; Smith, L.

1959-01-01T23:59:59.000Z

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

Acceleration Modules in Linear Induction Accelerators  

E-Print Network (OSTI)

Linear Induction Accelerator (LIA) is a unique type of accelerator, which is capable to accelerate kiloAmpere charged particle current to tens of MeV energy. The present development of LIA in MHz busting mode and successful application into synchrotron broaden LIAs usage scope. Although transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. Authors examined the transition of the magnetic cores functions during LIA acceleration modules evolution, distinguished transformer type and transmission line type LIA acceleration modules, and reconsidered several related issues based on transmission line type LIA acceleration module. The clarified understanding should be helpful in the further development and design of the LIA acceleration modules.

Wang, Shaoheng

2013-01-01T23:59:59.000Z

8

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

9

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

10

The Particle Adventure | Accelerators and Particle Detectors  

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

Waves and particles The world's meterstick Mass and energy Energy-mass conversion Accelerators How to obtain particles to accelerate Accelerating particles Accelerating...

11

Portable Linear Accelerator Development  

Science Conference Proceedings (OSTI)

This report describes Minac-3, a miniaturized linear accelerator system. It covers the current equipment capabilities and achievable modifications, applications information for prospective users, and technical information on high-energy radiography that is useful for familiarization and planning. The design basis, development, and applications history of Minac are also summarized.

1982-12-01T23:59:59.000Z

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

Linear Accelerator | Advanced Photon Source  

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

electrons emitted from a cathode heated to 1100 C. The electrons are accelerated by high-voltage alternating electric fields in a linear accelerator (linac; photo below)....

14

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

15

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

Science Conference Proceedings (OSTI)

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

Physics Out Loud - Particle Accelerator  

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

Nucleus Previous Video (Nucleus) Physics Out Loud Main Index Next Video (Particle Resonance) Particle Resonance Particle Accelerator Andrew Hutton, Director of Accelerators at...

17

Charged particle accelerator grating  

DOE Patents (OSTI)

A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

Palmer, R.B.

1985-09-09T23:59:59.000Z

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

Annual Planning Summaries: Stanford Linear Accelerator (SLAC...  

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

Stanford Linear Accelerator (SLAC) Annual Planning Summaries: Stanford Linear Accelerator (SLAC) Document(s) Available For Download January 11, 2012 2012 Annual Planning Summary...

20

HIGH ENERGY PARTICLE ACCELERATOR  

DOE Patents (OSTI)

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

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

1959-04-14T23:59:59.000Z

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.


21

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 when it 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, W.M.

1991-03-19T23:59:59.000Z

22

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

23

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

24

Laser Wakefield Particle Accelerators Project at NERSC  

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

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

25

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, B.M.

1995-12-31T23:59:59.000Z

26

Radiative Effects on Particle Acceleration via Relativistic Electromagnetic Expansion  

E-Print Network (OSTI)

We study the radiation effect on the diamagnetic relativistic pulse accelerator (DPRA) in two-and-half-dimensional particle-in-cell (PIC) plasma simulation with magnetized electron-positron plasmas. Radiation damping force is self-consistently calculated for each particle, which reduces the acceleration force and converts particle energy to radiation. The emitted radiation is strongly linearly polarized and peaked within few degrees from the direction of Poynting flux due to the relativistic acceleration by the DPRA.

Noguchi, K; Nishimura, K; Noguchi, Koichi; Liang, Edison; Nishimura, Kazumi

2004-01-01T23:59:59.000Z

27

Characterisation of electron beams from laser-driven particle accelerators  

Science Conference Proceedings (OSTI)

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

28

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOE Patents (OSTI)

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

Maschke, A.W.

1984-04-16T23:59:59.000Z

29

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

30

2011 Annual Planning Summary for Stanford Linear Accelerator...  

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

Stanford Linear Accelerator Center Site Office (SLAC) 2011 Annual Planning Summary for Stanford Linear Accelerator Center Site Office (SLAC) The ongoing and projected Environmental...

31

Slow Waveguide Structures for Particle Accelerators  

A waveguide design that can save time and money in the construction and tuning ofa particle accelerator was developed by ORNL researchers. Particle ...

32

Particle Acceleration by Electromagnetic-Dominated Outflows  

E-Print Network (OSTI)

We review recent developments in particle acceleration by Poynting flux using plasma kinetic simulations, and discuss their potential applications to gamma-ray burst phenomenology

Edison Liang; Koichi Noguchi

2006-04-19T23:59:59.000Z

33

Particle Acceleration by Electromagnetic-Dominated Outflows  

E-Print Network (OSTI)

We review recent developments in particle acceleration by Poynting flux using plasma kinetic simulations, and discuss their potential applications to gamma-ray burst phenomenology

Liang, E; Liang, Edison; Noguchi, Koichi

2006-01-01T23:59:59.000Z

34

Radiative Effects on Particle Acceleration in Electromagnetic Dominated Outflows  

E-Print Network (OSTI)

Plasma outflows from gamma-ray bursts (GRB), pulsar winds, relativistic jets, and ultra-intense laser targets radiate high energy photons. However, radiation damping is ignored in conventional PIC simulations. In this letter, we study the radiation damping effect on particle acceleration via Poynting fluxes in two-and-half-dimensional particle-in-cell (PIC) plasma simulation of electron-positron plasmas. Radiation damping force is self-consistently calculated for each particle and reduces the net acceleration force. The emitted radiation is peaked within a few degrees from the direction of Poynting flux and strongly linear-polarized.

Koichi Noguchi; Edison Liang; Kazumi Nishimura

2004-12-14T23:59:59.000Z

35

Slow Waveguide Structures for Particle Accelerators  

ORNL 2010-G00971/jcn UT-B ID 200802074 Slow Waveguide Structures for Particle Accelerators Technology Summary A waveguide design that can save time and money in the ...

36

Twisted waveguides for particle accelerator applications  

E-Print Network (OSTI)

A novel microwave device for accelerating charged particles based on twisted waveguide is presented. Twisted guides support slow-wave TM modes whose phase velocity could reach the speed of light c. The axial electric field ...

Wilson, Joshua L.

37

Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources  

E-Print Network (OSTI)

of high- gradient, laser plasma particle accelerators.particle accelerators, plasmas can sustain acceleratingthat use laser-driven plasma waves. These plasma- based

Geddes, Cameron G.R.

2010-01-01T23:59:59.000Z

38

SLAC National Accelerator Laboratory - SLAC Public Lecture: Particle...  

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

Division will present a free public lecture, "Particle Accelerator on a Chip." Accelerators are huge and expensive, miles-long tubes that produce high-energy particles to...

39

Linearized error analysis for an accelerator and application to the APS injector synchrotron  

SciTech Connect

This paper presents a tolerance budget for accelerators dictated by the linear transverse dynamics of particle motion. The linearized equations satisfied by the particle motion when errors in the lattice are present are given along with the solution to these equations. The forms of these errors giving rise to the linearized equation are stated. These results are used to derive a tolerance budget for the Advanced Photon Source (APS) injector synchrotron.

Koul, R.K.; Mills, F.E.

1995-07-01T23:59:59.000Z

40

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

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

Applications of large-scale computation to particle accelerators  

SciTech Connect

The rapid growth in the power of large-scale computers has had a revolutionary effect on the study of charged-particle accelerators that is similar to the impact of smaller computers on everyday life. Before an accelerator is built, it is now the absolute rule to simulate every component and subsystem by computer to establish modes of operation and tolerances. We will bypass the important and fruitful areas of control and operation, and consider only application to design and diagnostic interpretation. Applications of computers can be divided into separate categories including: component design, system design, stability studies, cost optimization, and operating condition simulation. For the purposes of this report, we will choose a few examples from the above categories to illustrate the methods used, and discuss the significance of the work to the project. We also briefly discuss the accelerator project itself. The examples that will be discussed are: The design of accelerator structures for electron-positron linear colliders and circular colliding beam systems, simulation of the wake fields from multibunch electron beams for linear colliders. Particle-in-cell simulation of space-charge dominated beams for an experimental linear induction accelerator for Heavy Ion Fusion.

Herrmannsfeldt, W.B.

1991-05-01T23:59:59.000Z

42

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

43

Variable-energy drift-tube linear accelerator  

SciTech Connect

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

44

Drift tube suspension for high intensity linear accelerators  

SciTech Connect

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

45

Non-accelerator particle physics  

SciTech Connect

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

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

1991-09-01T23:59:59.000Z

46

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

47

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

48

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

49

Exact acceleration of linear object detectors  

Science Conference Proceedings (OSTI)

We describe a general and exact method to considerably speed up linear object detection systems operating in a sliding, multi-scale window fashion, such as the individual part detectors of part-based models. The main bottleneck of many of those systems ... Keywords: linear object detection, part-based models

Charles Dubout; Fran$#231;ois Fleuret

2012-10-01T23:59:59.000Z

50

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

51

LOADED WAVE GUIDES FOR LINEAR ACCELERATORS  

DOE Patents (OSTI)

A periodically loaded waveguide having substantially coaxially arranged elements which provide an axial field for the acceleration of electrons is described. Radiofrequency energy will flow in the space between the inner wall of an outer guide and the peripheries of equally spaced irises or washes arranged coaxially with each other and with the outer guide, where the loading due to the geometry of the irises is such as to reduce the phase velocity of the r-f energy flowing in the guide from a value greater than that of light to the velocity of light or less.

Walkinshaw, W.; Mullett, L.B.

1959-12-01T23:59:59.000Z

52

Considerations for a Dielectric-based Two-beam-accelerator Linear...  

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

WEPE033 Proceedings of IPAC'10, Kyoto, Japan 3428 03 Linear Colliders, Lepton Accelerators and New Acceleration Techniques A03 Linear Colliders high coupling coefficient...

53

BNL | Accelerating Particles Accelerates Science - With Big Benefits...  

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

program focused on developing the next crop of bold accelerator scientists and engineers. Photo of CASE participants The Center for Accelerator Science and Education (CASE)...

54

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)  

E-Print Network (OSTI)

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)

Grelick, A E; Arnold, N; White, M

1996-01-01T23:59:59.000Z

55

Construction, Commissioning and Operational Experience of the Advanced Photon Source (APS) Linear Accelerator  

E-Print Network (OSTI)

Construction, Commissioning and Operational Experience of the Advanced Photon Source (APS) Linear Accelerator

White, M; Berg, W; Cours, A; Fuja, R; Grelick, A E; Ko, K; Qian, Y L; Russell, T; Sereno, N S; Wesolowski, W

1996-01-01T23:59:59.000Z

56

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

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

experiment with tiny particles? - A linear or circular accelerator? All accelerators are either linear or circular, the difference being whether the particle is shot like a bullet...

57

Stanford Linear Accelerator Center Stanford Synchrotron Radiation Laboratory  

E-Print Network (OSTI)

1 of 13 10/16/2006 FACILITY EMERGENCY PLAN February, 2006 SSRL Safety Office Stanford Linear Accelerator Center Menlo Park, California TABLE OF CONTENTS PREFACE SSRL EMERGENCY PLAN SECTION A: SAFETY RESPONSIBILITIES 1.0 SSRL Emergency Personnel 1.1 SLAC Person - In - Charge (PIC) 1.2 SSRL Beamline Duty Operator

Ford, James

58

Phase and amplitude detection system for the Stanford Linear Accelerator  

Science Conference Proceedings (OSTI)

A computer controlled phase and amplitude detection system to measure and stabilize the rf power sources in the Stanford Linear Accelerator is described. This system measures the instantaneous phase and amplitude of a 1 microsecond 2856 MHz rf pulse and will be used for phase feedback control and for amplitude and phase jitter detection. This paper discusses the measurement system performance requirements for the operation of the Stanford Linear Collider, and the design and implementation of the phase and amplitude detection system. The fundamental software algorithms used in the measurement are described, as is the performance of the prototype phase and amplitude detector system.

Fox, J.D.; Schwarz, H.D.

1983-01-01T23:59:59.000Z

59

Linear induction accelerator and pulse forming networks therefor  

DOE Green Energy (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

60

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

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

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

62

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

63

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

64

Accelerators  

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

Accelerators Elementary Particles Detectors Accelerators Visit World Labs For Children - for younger people For Children The Electric Force For Children Electric Force Fields For...

65

Solar Particle Acceleration at Reconnecting 3D Null Points  

E-Print Network (OSTI)

Context: The strong electric fields associated with magnetic reconnection in solar flares are a plausible mechanism to accelerate populations of high energy, non-thermal particles. One such reconnection scenario occurs at a 3D magnetic null point, where global plasma flows give rise to strong currents in the spine axis or fan plane. Aims: To understand the mechanism of charged particle energy gain in both the external drift region and the diffusion region associated with 3D magnetic reconnection. In doing so we evaluate the efficiency of resistive spine and fan models for particle acceleration, and find possible observables for each. Method: We use a full orbit test particle approach to study proton trajectories within electromagnetic fields that are exact solutions to the steady and incompressible magnetohydrodynamic equations. We study single particle trajectories and find energy spectra from many particle simulations. The scaling properties of the accelerated particles with respect to field and plasma para...

Stanier, Adam J; Dalla, Silvia

2012-01-01T23:59:59.000Z

66

Towards radiation pressure acceleration of protons using linearly polarized ultrashort petawatt laser pulses  

E-Print Network (OSTI)

Particle acceleration using ultraintense, ultrashort laser pulses is one of the most attractive topics in relativistic laser-plasma research. We report proton/ion acceleration in the intensity range of 5x1019 W/cm2 to 3.3x1020 W/cm2 by irradiating linearly polarized, 30-fs, 1-PW laser pulses on 10- to 100-nm-thick polymer targets. The proton energy scaling with respect to the intensity and target thickness was examined. The experiments demonstrated, for the first time with linearly polarized light, a transition from the target normal sheath acceleration to radiation pressure acceleration and showed a maximum proton energy of 45 MeV when a 10-nm-thick target was irradiated by a laser intensity of 3.3x1020 W/cm2. The experimental results were further supported by two- and three-dimensional particle-in-cell simulations. Based on the deduced proton energy scaling, proton beams having an energy of ~ 200 MeV should be feasible at a laser intensity of 1.5x1021 W/cm2.

Kim, I Jong; Kim, Chul Min; Kim, Hyung Taek; Sung, Jae Hee; Lee, Seong Ku; Yu, Tae Jun; Choi, Il Woo; Lee, Chang-Lyoul; Nam, Kee Hwan; Nickles, Peter V; Jeong, Tae Moon; Lee, Jongmin

2013-01-01T23:59:59.000Z

67

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

68

Transverse emittance dilution due to coupler kicks in linear accelerators  

E-Print Network (OSTI)

One of the main concerns in the design of low emittance linear accelerators (linacs) is the preservation of beam emittance. Here we discuss one possible source of emittance dilution due to transverse electromagnetic fields in the accelerating cavities of the linac caused by the power coupler geometry. It is common wisdom that emittance growth from coupler kicks can be strongly reduced by having the coupler location alternate from above to below the beam pipe so that the coupler kick from one cavity is compensated by that of the next. While this is correct, alternating the coupler location requires large technical changes in superconducting cryomodules where cryogenic pipes are arranged parallel to a string of several cavities. We show here that cavities with high external $Q$ have coupler kicks that change the sign of their phase when the coupler is moved from before to after the cavity, as long as one accelerates on crest. This implies that the emittance growth from one cavity can be canceled by the next, pr...

Buckley, Brandon

2007-01-01T23:59:59.000Z

69

Analysis of Laser Wakefield Particle Acceleration Data at NERSC  

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

Analysis of Laser Wakefield Particle Acceleration Data LWFAIllustrationSmall.png In collaboration with researchers of the LOASIS program (LBNL) and the SciDAC SDM center (LBNL) we...

70

Slow Waveguide Structures for Particle Accelerators  

The beam line is used for basic science investigations as well as for applications ... waveguide structure to support transmission of particles at ...

71

Particle trajectories and acceleration during 3D fan reconnection  

E-Print Network (OSTI)

Context. The primary energy release in solar flares is almost certainly due to magnetic reconnection, making this a strong candidate as a mechanism for particle acceleration. While particle acceleration in 2D geometries has been widely studied, investigations in 3D are a recent development. Two main classes of reconnection regimes at a 3D magnetic null point have been identified: fan and spine reconnection Aims. Here we investigate particle trajectories and acceleration during reconnection at a 3D null point, using a test particle numerical code, and compare the efficiency of the fan and spine regimes in generating an energetic particle population. Methods. We calculated the time evolution of the energy spectra. We discuss the geometry of particle escape from the two configurations and characterise the trapped and escaped populations. Results. We find that fan reconnection is less efficent than spine reconnection in providing seed particles to the region of strong electric field where acceleration is possible. The establishment of a steady-state spectrum requires approximately double the time in fan reconnection. The steady-state energy spectrum at intermediate energies (protons 1 keV to 0.1 MeV) is comparable in the fan and spine regimes. While in spine reconnection particle escape takes place in two symmetric jets along the spine, in fan reconnection no jets are produced and particles escape in the fan plane, in a ribbon-like structure.

S. Dalla; P. K. Browning

2008-11-07T23:59:59.000Z

72

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

73

RF System Upgrades to the Advanced Photon Source Linear Accelerator in Support of the Fel Operation  

E-Print Network (OSTI)

The S-band linear accelerator, which was built to be the source of particles and the front end of the Advanced Photon Source injector, is now also being used to support a low-energy undulator test line (LEUTL) and to drive a free-electron laser (FEL). The more severe rf stability requirements of the FEL have resulted in an effort to identify sources of phase and amplitude instability and implement corresponding upgrades to the rf generation chain and the measurement system. Test data and improvements implemented and planned are described

Smith, T L; Grelick, A E; Pile, G; Nassiri, A; Arnold, N

2000-01-01T23:59:59.000Z

74

Characterizing flows with an instrumented particle measuring Lagrangian accelerations  

E-Print Network (OSTI)

We present in this article a novel Lagrangian measurement technique: an instrumented particle which continuously transmits the force/acceleration acting on it as it is advected in a flow. We develop signal processing methods to extract information on the flow from the acceleration signal transmitted by the particle. Notably, we are able to characterize the force acting on the particle and to identify the presence of a permanent large-scale vortex structure. Our technique provides a fast, robust and efficient tool to characterize flows, and it is particularly suited to obtain Lagrangian statistics along long trajectories or in cases where optical measurement techniques are not or hardly applicable.

Zimmermann, Robert; Gasteuil, Yoann; Volk, Romain; Pinton, Jean-François

2012-01-01T23:59:59.000Z

75

Particle acceleration by fluctuating electric fields at a magnetic field null point  

E-Print Network (OSTI)

Particle acceleration consequences from fluctuating electric fields superposed on an X-type magnetic field in collisionless solar plasma are studied. Such a system is chosen to mimic generic features of dynamic reconnection, or the reconnective dissipation of a linear disturbance. We explore numerically the consequences for charged particle distributions of fluctuating electric fields superposed on an X-type magnetic field. Particle distributions are obtained by numerically integrating individual charged particle orbits when a time varying electric field is superimposed on a static X-type neutral point. This configuration represents the effects of the passage of a generic MHD disturbance through such a system. Different frequencies of the electric field are used, representing different possible types of wave. The electric field reduces with increasing distance from the X-type neutral point as in linear dynamic magnetic reconnection. The resulting particle distributions have properties that depend on the amplitude and frequency of the electric field. In many cases a bimodal form is found. Depending on the timescale for variation of the electric field, electrons and ions may be accelerated to different degrees and often have energy distributions of different forms. Protons are accelerated to $\\gamma$-ray producing energies and electrons to and above hard X-ray producing energies in timescales of 1 second. The acceleration mechanism is possibly important for solar flares and solar noise storms but is also applicable to all collisionless plasmas.

P. Petkaki; A. L. MacKinnon

2007-07-09T23:59:59.000Z

76

Dynamics of Particles in Non Scaling FFAG Accelerators  

E-Print Network (OSTI)

Non scaling Fixed-Field Alternating Gradient (FFAG) accelerators have an unprecedented potential for muon acceleration, as well as for medical purposes based on carbon and proton hadron therapy. They also represent a possible active element for an Accelerator Driven Subcritical Reactor (ADSR). Starting from first principle the Hamiltonian formalism for the description of the dynamics of particles in non scaling FFAG machines has been developed. The stationary reference (closed) orbit has been found within the Hamiltonian framework. The dependence of the path length on the energy deviation has been described in terms of higher order dispersion functions. The latter have been used subsequently to specify the longitudinal part of the Hamiltonian. It has been shown that higher order phase slip coefficients should be taken into account to adequately describe the acceleration in non scaling FFAG accelerators. A complete theory of the fast (serpentine) acceleration in non scaling FFAGs has been developed. An example...

Jones, James K; Smith, Susan L; Tzenov, Stephan I

2009-01-01T23:59:59.000Z

77

Ion effects in future circular and linear accelerators  

SciTech Connect

In this paper, the author discusses ion effects relevant to future storage rings and linear colliders. The author first reviews the conventional ion effects observed in present storage rings and then discusses how these effects will differ in the next generation of rings and linacs. These future accelerators operate in a new regime because of the high current long bunch trains and the very small transverse beam emittances. Usually, storage rings are designed with ion clearing gaps to prevent ion trapping between bunch trains or beam revolutions. Regardless, ions generated within a single bunch train can have significant effects. The same is true in transport lines and linacs, where typical vacuum pressures are relatively high. Amongst other effects, the author addresses the tune spreads due to the ions and the resulting filamentation which can severely limit emittance correction techniques in future linear colliders, the bunch-to-bunch coupling due to the ions which can cause a multi-bunch instability with fast growth rates, and the betatron coupling and beam halo creation which limit the vertical emittance and beam lifetimes.

Raubenheimer, T.O.

1995-05-01T23:59:59.000Z

78

Stochastic wake field particle acceleration in Gamma-Ray Bursts  

E-Print Network (OSTI)

Gamma-Ray Burst (GRB) prompt emission can, for specific conditions, be so powerful and short-pulsed to strongly influence any surrounding plasma. In this paper, we briefly discuss the possibility that a very intense initial burst of radiation produced by GRBs satisfy the intensity and temporal conditions to cause stochastic wake-field particle acceleration in a surrounding plasma of moderate density. Recent laboratory experiments clearly indicate that powerful laser beam pulses of tens of femtosecond duration hitting on target plasmas cause efficient particle acceleration and betatron radiation up to tens of MeV. We consider a simple but realistic GRB model for which particle wake-field acceleration can first be excited by a very strong low-energy precursor, and then be effective in producing the observed prompt X-ray and gamma-ray GRB emission. We also briefly discuss some of the consequences of this novel GRB emission mechanism.

G. Barbiellini; F. Longo; N. Omodei; A. Celotti; M. Tavani

2006-04-11T23:59:59.000Z

79

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).

80

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

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

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron  

E-Print Network (OSTI)

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre and documentation. For further questions please do not hesitate to contact Prof. Dr. Chris Meier (chris.meier@chemie-Mail to: Deutsches Elektronen-Synchrotron DESY Human Resources Department | Code: EM085/2013 NotkestraÃ?e

82

Tuning the DARHT Axis-II linear induction accelerator focusing  

SciTech Connect

Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an accelerator cell to replace a failed solenoid in March of 2012. We took advantage of this opportunity to improve the design of the focusing tune with better models of the remaining partially failed solenoids, better estimates of beam initial conditions, and better values for pulsed-power voltages. As with all previous tunes for Axis-II, this one incorporates measures to mitigate beam-breakup (BBU) instability, image displacement instability (IDI), corkscrew (sweep), and emittance growth. Section II covers the general approach to of design of focusing solenoid tunes for the DARHT Axis-2 LIA. Section III explains the specific requirements and simulations needed to design the tune for the injector, which includes the thermionic electron source, diode, and six induction cells. Section IV explains the requirements and simulations for tuning the main accelerator, which consists of 68 induction cells. Finally, Section V explores sensitivity of the tune to deviations of parameters from nominal, random variations, and uncertainties in values. Four appendices list solenoid settings for this new tune, discuss comparisons of different simulation codes, show halo formation in mismatched beams, and present a brief discussion of the beam envelope equation, which is the heart of the method used to design LIA solenoid tunes.

Ekdahl, Carl A. [Los Alamos National Laboratory

2012-04-24T23:59:59.000Z

83

Failure Analysis of the Beam Vacuum in the Superconducting Cavities of the TESLA Main Linear Accelerator  

E-Print Network (OSTI)

1 Failure Analysis of the Beam Vacuum in the Superconducting Cavities of the TESLA Main Linear Hamburg, Germany Abstract For the long term successful operation of the superconducting TESLA accelerator The beam vacuum system of the TESLA main linear accelerators contains about 20.000 superconducting cavities

84

Linear water waves with vorticity: rotational features and particle paths  

E-Print Network (OSTI)

Steady linear gravity waves of small amplitude travelling on a current of constant vorticity are found. For negative vorticity we show the appearance of internal waves and vortices, wherein the particle trajectories are not any more closed ellipses. For positive vorticity the situation resembles that of Stokes waves, but for large vorticity the trajectories are affected.

Mats Ehrnstrom; Gabriele Villari

2007-12-04T23:59:59.000Z

85

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

Science Conference Proceedings (OSTI)

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

McNeur, J.; Hazra, K. S.; Liu, G.; Sozer, E. B.; Travish, G.; Yoder, R. B. [UCLA Dept. of Physics and Astronomy, Los Angeles, CA 90095 (United States); Manhattanville College, Physics Dept., 2900 Purchase St., Purchase, NY 10577 (United States)

2012-12-21T23:59:59.000Z

86

Particle Acceleration in Geospace and Its Association With Solar Events  

E-Print Network (OSTI)

Particle acceleration is a prominent feature of the geomagnetic storm, which is the prime dynamic process in Geospace - the near-Earth space environment. Magnetic storms have their origin in solar events, which are transient disturbances of the solar atmosphere and radiation that propagate as variations of the solar wind fields and particles through interplanetary space to the Earth's orbit. During magnetic storms, ions of both solar wind origin and terrestrial origin are accelerated and form an energetic ring current in the inner magnetosphere. This current has global geomagnetic effects, which have both physical and technical implications. Recently it has been shown that large magnetic storms, which exhibit an unusually energized ionospheric plasma component, are closely associated with coronal mass ejections (CMEs). This implies a cause-effect chain connecting solar events through CMEs and the solar wind with the acceleration of terrestrial ion populations whicheventually constitute the main source of global geomagnetic disturbances. Here we present spacecraft observations related to storm-time particle acceleration and assess the observations in the framework of causes and effects of solar-terrestrial relationships.

I. A. Daglis; W. I. Axford; E. T. Sarris; S. Livi; B. Wilken

1997-01-01T23:59:59.000Z

87

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-

88

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.

89

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

90

USING THE ONLINE SINGLE PARTICLE MODEL FOR SNS ACCELERATOR TUNING  

Science Conference Proceedings (OSTI)

This paper describes the usage of the XAL online model for transverse and longitudinal tuning of the SNS linac. Most of the SNS control room physics applications are based on the XAL online model, which can be synchronized with an accelerator live state and used to tune the machine. Advantages of a simple and fast single particle model for orbit correction and longitudinal dynamics control in the SNS control room are discussed.

Shishlo, Andrei P [ORNL; Aleksandrov, Alexander V [ORNL

2008-01-01T23:59:59.000Z

91

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

Science Conference Proceedings (OSTI)

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

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

2001-10-01T23:59:59.000Z

92

Towards dense linear algebra for hybrid GPU accelerated manycore systems  

Science Conference Proceedings (OSTI)

We highlight the trends leading to the increased appeal of using hybrid multicore+GPU systems for high performance computing. We present a set of techniques that can be used to develop efficient dense linear algebra algorithms for these systems. We illustrate ... Keywords: Dense linear algebra, Graphics processing units, Hybrid computing, Multicore processors, Parallel algorithms

Stanimire Tomov; Jack Dongarra; Marc Baboulin

2010-06-01T23:59:59.000Z

93

DOE - Office of Legacy Management -- Stanford Linear Accelerator...  

Office of Legacy Management (LM)

Center was established in 1962 as a research facility for high energy particle physics. The Environmental Management mission at this site is to clean up soils and...

94

Dynamic MLC leaf sequencing for integrated linear accelerator control systems  

Science Conference Proceedings (OSTI)

Purpose: Leaf positions for dynamic multileaf collimator (DMLC) intensity modulated radiation therapy must be closely synchronized with MU delivery. For the Varian C3 series MLC controller, if the planned trajectory (leaf position vs. MU) requires velocities exceeding the capability of the MLC, the leaves fall behind the planned positions, causing the controller to momentarily hold the beam and thereby introduce dosimetric errors. We investigated the merits of a new commercial linear accelerator, TrueBeam, that integrates MLC control with prospective dose rate modulation. If treatment is delivered at dose rates so high that leaves would fall behind, the controller reduces the dose rate such that harmony between MU and leaf position is preserved. Methods: For three sets of DMLC leaf trajectories, point doses and two-dimensional dose distributions were measured in phantom using an ionization chamber and film, respectively. The first set, delivered using both a TrueBeam and a conventional C3 controller, comprised a single leaf bank closing at planned velocities of 2.4, 7.1, and 14 cm/s. The maximum achievable leaf velocity for both systems was 3 cm/s. The remaining two sets were derived from clinical fluence maps using a commercial treatment planning system for a range of planned dose rates and were delivered using TrueBeam set to the maximum dose rate, 600 MU/min. Generating trajectories using a planned dose rate that is lower than the delivery dose rate effectively increased the leaf velocity constraint used by the planning system for trajectory calculation. The second set of leaf trajectories was derived from two fluence maps containing regions of zero fluence obtained from representative beams of two different patient treatment plans. The third set was obtained from all nine fields of a head and neck treatment plan. For the head and neck plan, dose-volume histograms of the spinal cord and target for each planned dose rate were obtained. Results: For the single closing leaf bank trajectories, the TrueBeam control system reduced the dose rate such that the leaf velocity was less than the maximum. Dose deviations relative to the 2.4 cm/s trajectory were less than 3%. For the conventional controller, the leaves repeatedly fell behind the planned positions until the beam hold threshold was reached, resulting in deviations of up to 19% relative to the 2.4 cm/s trajectory. For the two clinical fluence maps, reducing the planned dose rate reduced the dose in the zero fluence regions by 15% and 24% and increased the delivery time by 5 s and 14 s. No significant differences were noted in the high and intermediate dose regions measured using film. The DVHs for the head and neck plan showed a 10% reduction in cord dose for 20 MU/min relative to 600 MU/min sequencing dose rate, which was confirmed by measurement. No difference in target DVHs were observed. The reduction in cord dose increased total treatment time by 1.8 min. Conclusions: Leaf sequencing algorithms for integrated control systems should be modified to reflect the reduced importance of maximum leaf velocity for accurate dose delivery.

Popple, Richard A.; Brezovich, Ivan A. [Department of Radiation Oncology, University of Alabama at Birmingham, 1700 6th Avenue South, Birmingham, Alabama 35249-6832 (United States)

2011-11-15T23:59:59.000Z

95

DIFFUSIVE SHOCK ACCELERATION IN TEST-PARTICLE REGIME  

Science Conference Proceedings (OSTI)

We examine the test-particle solution for diffusive shock acceleration, based on simple models for thermal leakage injection and Alfvenic drift. The critical injection rate, {xi}{sub c}, above which the cosmic-ray (CR) pressure becomes dynamically significant depends mainly on the sonic shock Mach number, M, and preshock gas temperature, T{sub 1}. In the hot-phase interstellar medium (ISM) and intracluster medium, {xi}{sub c} {approx} 10. For T{sub 1} = 10{sup 6} K, for example, the test-particle solution would be valid if the injection momentum p{sub inj} >3.8p{sub th} (where p{sub th} is thermal momentum). This leads to a postshock CR pressure less than 10% of the shock ram pressure. If the Alfven speed is comparable to the sound speed in the preshock flow, as in the hot-phase ISM, the power-law slope of CR spectrum can be significantly softer than the canonical test-particle slope. Then, the CR spectrum at the shock can be approximated by the revised test-particle power law with an exponential cutoff at the highest accelerated momentum, p{sub max}(t). An analytic form of the exponential cutoff is also suggested.

Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Ryu, Dongsu, E-mail: kang@uju.es.pusan.ac.k, E-mail: ryu@canopus.cnu.ac.k [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

2010-09-20T23:59:59.000Z

96

FLUKA calculations of radionuclides, star, and neutron fluence in soil around high-energy electron and proton linear accelerators  

E-Print Network (OSTI)

FLUKA calculations of radionuclides, star, and neutron fluence in soil around high-energy electron and proton linear accelerators

Puryear, A; Rokni, S H

2002-01-01T23:59:59.000Z

97

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

98

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

99

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.;

100

Accelerated Iterative Method for Solving Steady Problems of Linearized Atmospheric Models  

Science Conference Proceedings (OSTI)

A new approach, referred to as the accelerated iterative method (AIM), is developed for obtaining steady atmospheric responses with a zonally varying basic state. The linear dynamical operator is divided into two parts, one associated with the ...

Masahiro Watanabe; Fei-fei Jin; Lin Pan

2006-12-01T23:59:59.000Z

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.


101

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

102

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.

103

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

104

The First Observation of Intra Beam Stripping of Negative Hydrogen in a Superconducting Linear Accelerator  

Science Conference Proceedings (OSTI)

We report on an experiment in which a negative hydrogen ions beam in the Spallation Neutron Source (SNS) linear accelerator was replaced with a beam of protons with similar size and dynamics. Beam loss in the superconducting part of the SNS accelerator was at least an order of magnitude lower for the proton beam. Also beam loss has a stronger dependence on intensity with H- than with proton beams. These measurements verify a recent theoretical explanation of unexpected beam losses in the SNS superconducting linear accelerator based on an intra beam stripping mechanism for negative hydrogen ions. An identification of the new physics mechanism for beam loss is important for the design of new high current linear ion accelerators and the performance improvement of existing machines

Aleksandrov, Alexander V [ORNL; Plum, Michael A [ORNL; Shishlo, Andrei P [ORNL; Galambos, John D [ORNL

2012-01-01T23:59:59.000Z

105

Efficiency of Nonlinear Particle Acceleration at Cosmic Structure Shocks  

E-Print Network (OSTI)

We have calculated the evolution of cosmic ray (CR) modified astrophysical shocks for a wide range of shock Mach numbers and shock speeds through numerical simulations of diffusive shock acceleration (DSA) in 1D quasi- parallel plane shocks. The simulations include thermal leakage injection of seed CRs, as well as pre-existing, upstream CR populations. Bohm-like diffusion is assumed. We model shocks similar to those expected around cosmic structure pancakes as well as other accretion shocks driven by flows with upstream gas temperatures in the range $T_0=10^4-10^{7.6}$K and shock Mach numbers spanning $M_s=2.4-133$. We show that CR modified shocks evolve to time-asymptotic states by the time injected particles are accelerated to moderately relativistic energies ($p/mc \\gsim 1$), and that two shocks with the same Mach number, but with different shock speeds, evolve qualitatively similarly when the results are presented in terms of a characteristic diffusion length and diffusion time. For these models the time asymptotic value for the CR acceleration efficiency is controlled mainly by shock Mach number. The modeled high Mach number shocks all evolve towards efficiencies $\\sim 50$%, regardless of the upstream CR pressure. On the other hand, the upstream CR pressure increases the overall CR energy in moderate strength shocks ($M_s \\sim {\\rm a few}$). (abridged)

H. Kang; T. W. Jones

2004-10-29T23:59:59.000Z

106

Analytical description of nonlinear particle transport in slab turbulence: High particle energies and stochastic acceleration  

Science Conference Proceedings (OSTI)

Pitch-angle scattering, parallel spatial diffusion, and stochastic acceleration of cosmic rays are investigated analytically. Based on a second-order quasilinear theory, we derive analytical expressions for the aforementioned transport parameters for all possible magnetic field strengths and particle energies. This work complements previous work where only parallel diffusion for low energetic particles was considered. Furthermore, we compute the first time the momentum diffusion coefficient. It is also shown that the relation between the momentum diffusion coefficient and the parallel spatial diffusion coefficient is more complicated than assumed in previous work.

Shalchi, A. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)

2012-10-15T23:59:59.000Z

107

International Linear Collider Accelerator Physics R&D  

Science Conference Proceedings (OSTI)

ILC work at Illinois has concentrated primarily on technical issues relating to the design of the accelerator. Because many of the problems to be resolved require a working knowledge of classical mechanics and electrodynamics, most of our research projects lend themselves well to the participation of undergraduate research assistants. The undergraduates in the group are scientists, not technicians, and find solutions to problems that, for example, have stumped PhD-level staff elsewhere. The ILC Reference Design Report calls for 6.7 km circumference damping rings (which prepare the beams for focusing) using “conventional” stripline kickers driven by fast HV pulsers. Our primary goal was to determine the suitability of the 16 MeV electron beam in the AØ region at Fermilab for precision kicker studies.We found that the low beam energy and lack of redundancy in the beam position monitor system complicated the analysis of our data. In spite of these issues we concluded that the precision we could obtain was adequate to measure the performance and stability of a production module of an ILC kicker, namely 0.5%. We concluded that the kicker was stable to an accuracy of ~2.0% and that we could measure this precision to an accuracy of ~0.5%. As a result, a low energy beam like that at AØ could be used as a rapid-turnaround facility for testing ILC production kicker modules. The ILC timing precision for arrival of bunches at the collision point is required to be 0.1 picosecond or better. We studied the bunch-to-bunch timing accuracy of a “phase detector” installed in AØ in order to determine its suitability as an ILC bunch timing device. A phase detector is an RF structure excited by the passage of a bunch. Its signal is fed through a 1240 MHz high-Q resonant circuit and then down-mixed with the AØ 1300 MHz accelerator RF. We used a kind of autocorrelation technique to compare the phase detector signal with a reference signal obtained from the phase detector’s response to an event at the beginning of the run. We determined that the device installed in our beam, which was instrumented with an 8-bit 500 MHz ADC, could measure the beam timing to an accuracy of 0.4 picoseconds. Simulations of the device showed that an increase in ADC clock rate to 2 GHz would improve measurement precision by the required factor of four. As a result, we felt that a device of this sort, assuming matters concerning dynamic range and long-term stability can be addressed successfully, would work at the ILC. Cost effective operation of the ILC will demand highly reliable, fault tolerant and adaptive solutions for both hardware and software. The large numbers of subsystems and large multipliers associated with the modules in those subsystems will cause even a strong level of unit reliability to become an unacceptable level of system availability. An evaluation effort is underway to evaluate standards associated with high availability, and to guide ILC development with standard practices and well-supported commercial solutions. One area of evaluation involves the Advanced Telecom Computing Architecture (ATCA) hardware and software. We worked with an ATCA crate, processor monitors, and a small amount of ATCA circuit boards in order to develop a backplane “spy” board that would let us watch the ATCA backplane communications and pursue development of an inexpensive processor monitor that could be used as a physics-driven component of the crate-level controls system. We made good progress, and felt that we had determined a productive direction to extend this work. We felt that we had learned enough to begin designing a workable processor monitor chip if there were to be sufficient interest in ATCA shown by the ILC community. Fault recognition is a challenging issue in the crafting a high reliability controls system. With tens of thousands of independent processors running hundreds of thousands of critical processes, how can the system identify that a problem has arisen and determine the appropriate steps to take to correct, or compensate, for the

George D. Gollin; Michael Davidsaver; Michael J. Haney; Michael Kasten; Jason Chang; Perry Chodash; Will Dluger; Alex Lang; Yehan Liu

2008-09-03T23:59:59.000Z

108

Preformed transient gas channels for laser wakefield particle acceleration  

SciTech Connect

Acceleration of electrons by laser-driven plasma wake fields is limited by the range over which a laser pulse can maintain its intensity. This distance is typically given by the Rayleigh range for the focused laser beam, usually on the order of 0.1 mm to 1 mm. For practical particle acceleration, interaction distances on the order of centimeters are required. Therefore, some means of guiding high intensity laser pulses is necessary. Light intensities on the order of a few times 10{sup 17} W/cm{sup 2} are required for laser wakefield acceleration schemes using near IR radiation. Gas densities on the order of or greater than 10{sup 17} cm{sup {minus}3} are also needed. Laser-atom interaction studies in this density and intensity regime are generally limited by the concomitant problems in beam propagation introduced by the creation of a plasma. In addition to the interaction distance limit imposed by the Rayleigh range, defocusing of the high intensity laser pulse further limits the peak intensity which can be achieved. To solve the problem of beam propagation limitations in laser-plasma wakefield experiments, two potential methods for creating transient propagation channels in gaseous targets are investigated. The first involves creation of a charge-neutral channel in a gas by an initial laser pulse, which then is ionized by a second, ultrashort, high-intensity pulse to create a waveguide. The second method involves the ionization of a gas column by an ultrashort pulse; a transient waveguide is formed by the subsequent expansion of the heated plasma into the neutral gas.

Wood, W.M.

1994-11-01T23:59:59.000Z

109

Solving Large Sparse Linear Systems in End-to-end Accelerator Structure Simulations  

Science Conference Proceedings (OSTI)

This paper presents a case study of solving very large sparse linear systems in end-to-end accelerator structure simulations. Both direct solvers and iterative solvers are investigated. A parallel multilevel preconditioner based on hierarchical finite element basis functions is considered and has been implemented to accelerate the convergence of iterative solvers. A linear system with matrix size 93,147,736 and with 3,964,961,944 non-zeros from 3D electromagnetic finite element discretization has been solved in less than 8 minutes with 1024 CPUs on the NERSC IBM SP. The resource utilization as well as the application performance for these solvers is discussed.

Lee, L

2004-01-23T23:59:59.000Z

110

Solving large-scale sparse eigenvalue problems and linear systems of equations for accelerator modeling  

SciTech Connect

The solutions of sparse eigenvalue problems and linear systems constitute one of the key computational kernels in the discretization of partial differential equations for the modeling of linear accelerators. The computational challenges faced by existing techniques for solving those sparse eigenvalue problems and linear systems call for continuing research to improve on the algorithms so that ever increasing problem size as required by the physics application can be tackled. Under the support of this award, the filter algorithm for solving large sparse eigenvalue problems was developed at Stanford to address the computational difficulties in the previous methods with the goal to enable accelerator simulations on then the world largest unclassified supercomputer at NERSC for this class of problems. Specifically, a new method, the Hemitian skew-Hemitian splitting method, was proposed and researched as an improved method for solving linear systems with non-Hermitian positive definite and semidefinite matrices.

Gene Golub; Kwok Ko

2009-03-30T23:59:59.000Z

111

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

112

(Stanford Linear Accelerator Center) annual environmental monitoring report, January--December 1989  

SciTech Connect

This progress report discusses environmental monitoring activities at the Stanford Linear Accelerator Center for 1989. Topics include climate, site geology, site water usage, land use, demography, unusual events or releases, radioactive and nonradioactive releases, compliance summary, environmental nonradiological program information, environmental radiological program information, groundwater protection monitoring ad quality assurance. 5 figs., 7 tabs. (KJD)

Not Available

1990-05-01T23:59:59.000Z

113

A Linear Analysis on the Acceleration of Zonal Flow by Baroclinic Instability. Part I. Terrestrial Atmosphere  

Science Conference Proceedings (OSTI)

A mechanism which accelerates the midlatitude zonal-mean wind is investigated by means of linear stability analysis for the wave-zonal flow interaction. Two kinds of models are analyzed: In the first, the basic state consists of an unstable zonal-...

T. Sasamori; K. Droegemeier

1983-10-01T23:59:59.000Z

114

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

115

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

116

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

117

Advance in Vertical Buffered Electropolishing on Niobium for Particle Accelerators*  

Science Conference Proceedings (OSTI)

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

118

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

SciTech Connect

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

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

2010-06-01T23:59:59.000Z

119

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

Science Conference Proceedings (OSTI)

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

120

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

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 conference on computer codes and the linear accelerator community  

SciTech Connect

The conference whose proceedings you are reading was envisioned as the second in a series, the first having been held in San Diego in January 1988. The intended participants were those people who are actively involved in writing and applying computer codes for the solution of problems related to the design and construction of linear accelerators. The first conference reviewed many of the codes both extant and under development. This second conference provided an opportunity to update the status of those codes, and to provide a forum in which emerging new 3D codes could be described and discussed. The afternoon poster session on the second day of the conference provided an opportunity for extended discussion. All in all, this conference was felt to be quite a useful interchange of ideas and developments in the field of 3D calculations, parallel computation, higher-order optics calculations, and code documentation and maintenance for the linear accelerator community. A third conference is planned.

Cooper, R.K. (comp.)

1990-07-01T23:59:59.000Z

122

LONGITUDINAL RESISTIVE INSTABILITIES OF INTENSE COASTING BEAMS IN PARTICLE ACCELERATORS  

E-Print Network (OSTI)

Conference on High Energy Accelerators, Brookhaven NationalLaboratory \\' 1.961 (Brookhaven National LaboratorYi Upton~of the International Brookhaven National i Conference on

Neil, V. Kelvin

2008-01-01T23:59:59.000Z

123

LONGITUDINAL RESISTIVE INSTABILITIES OF INTENSE COASTING BEAMS IN PARTICLE ACCELERATORS  

E-Print Network (OSTI)

Proceedings of the Brookhaven 1961 International ConferenceEnergy Accelerators, Brookhaven National Laboratory, 1961,Proceedings of the Brookhaven 1961 International Conference

Neil, V. Kelvin

2008-01-01T23:59:59.000Z

124

Advanced Modeling for Particle Accelerators Project at NERSC  

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

making fundamental scientific discoveries and DOE has clearly identified them as critical facilities for advancing research. Development and optimization of accelerators is...

125

Particle acceleration by electrostatic waves traveling perpendicular to nonuniform magnetic fields  

SciTech Connect

A novel method has been proposed for indefinite nonstochastic acceleration of particles by electrostatic waves propagating normal to a magnetic field. Use is made of a magnetic field inhomogeneity to prevent the particle from detrapping from the electrostatic wave. Numerical plots of particle trajectories are presented.

Rath, S.; Kaw, P.K.

1988-05-01T23:59:59.000Z

126

Beam loading voltage profile of an accelerating section with a linearly varying group velocity  

E-Print Network (OSTI)

The CLIC Tapered Damped accelerating Structure (TDS) has a 5.4% detuning of the lowest dipole mode. The geometrical variations that produce this detuning range also fix the fundamental mode's group velocity variation - very nearly linear with 0.108c (c is the speed of light) at the structure input to 0.054c at the output. In addition R'/Q also varies approximately linearly, from 22.3 kW/m at the input to 30 kW/m at the output. These variations result in a structure that is neither constant impedance nor constant gradient so the widely used relationships between structure length, input and average accelerating gradient are not applicable. In order to simplify the process of optimizing accelerator parameters an analytic expression for the voltage profile in a structure with a linearly varying group velocity has been derived. A more accurate numerical solution that includes the variation in R'/Q is also presented.

Wuensch, Walter

1999-01-01T23:59:59.000Z

127

Papers presented by the SL division at the 15th Particle Accelerator Conference, Washington, DC, USA, 17 - 20 May 1993  

E-Print Network (OSTI)

Papers presented by the SL division at the 15th Particle Accelerator Conference, Washington, DC, USA, 17 - 20 May 1993

CERN. Geneva

1993-01-01T23:59:59.000Z

128

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

Science Conference Proceedings (OSTI)

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

Wilson, Joshua L [ORNL

2008-09-01T23:59:59.000Z

129

Particle physicist's dreams about PetaelectronVolt laser plasma accelerators  

Science Conference Proceedings (OSTI)

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

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

2012-07-09T23:59:59.000Z

130

Future Prospects of Accelerator Science for Particle Physics  

Science Conference Proceedings (OSTI)

Future advances in understanding fundamental questions of nature require revolutionary developments in accelerator science to allow several orders of magnitude enhancements in terms of energy, intensity, faster timing, and higher resolution. The challenges of the 21st century (energy, power, environment, resources, cost, and space) also play a significant role in the development of accelerator tools. In this overview article, we consider several recent developments and ideas that may become steps in addressing the challenges and which may find their way into designs of accelerator tools of the future.

Seryi, Andrei; /SLAC

2012-06-15T23:59:59.000Z

131

#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

132

Visualizing electromagnetic field and particle simulations in accelerators with ParaView  

Science Conference Proceedings (OSTI)

SLAC performs large-scale simulations of Electromagnetic fields and particles for accelerator applications. These simulations run on intricate high order finite element meshes and produce field strengths spanning tens of orders of magnitudes. Such simulations ...

Greg L. Schussman

2009-11-01T23:59:59.000Z

133

Energy extraction and particle acceleration around a rotating black hole in Horava-Lifshitz gravity  

E-Print Network (OSTI)

Energy extraction and particle acceleration around a rotating black hole in Horava-Lifshitz gravity-Lifshitz gravity is studied. The strong dependence of the extracted energy from the special range of parameters that the fundamental parameter of the Horava-Lifshitz gravity can impose a limitation on the energy of the accelerating

134

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

135

Acceleration of heavy and light particles in turbulence: comparison between experiments and direct numerical simulations  

E-Print Network (OSTI)

We compare experimental data and numerical simulations for the dynamics of inertial particles with finite density in turbulence. In the experiment, bubbles and solid particles are optically tracked in a turbulent flow of water using an Extended Laser Doppler Velocimetry technique. The probability density functions (PDF) of particle accelerations and their auto-correlation in time are computed. Numerical results are obtained from a direct numerical simulation in which a suspension of passive pointwise particles is tracked, with the same finite density and the same response time as in the experiment. We observe a good agreement for both the variance of acceleration and the autocorrelation timescale of the dynamics; small discrepancies on the shape of the acceleration PDF are observed. We discuss the effects induced by the finite size of the particles, not taken into account in the present numerical simulations.

R. Volk; E. Calzavarini; G. Verhille; D. Lohse; N. Mordant; J. -F. Pinton; F. Toschi

2007-10-17T23:59:59.000Z

136

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

137

Low energy improvements to the Fermilab 400-MeV linear accelerator  

SciTech Connect

Improvements in the Fermilab operating 400-MeV linear accelerator injector are required to achieve the beam intensity and emittance requirement of the Proton Driver design study [5]. It has been determined that these requirements can be achieved by replacing the components in the Linac below 10 MeV. An improved H{sup {minus}} ion source with an electrostatic transport to a two-section Radio-Frequency Quadrupole (RFQ) accelerator, with the RFQ sections separated by a magnetic five-dimensional phase-space imaging system as used in an earlier Fermilab/SAIC PET Project, and a new 10-MeV drift-tube linac cavity have been studied. It appears possible that an H{sup {minus}} intensity of 4.5 x 10{sup 13} ions per pulse with an improvement in beam emittance from the present system can be achieved with the proposed changes.

Don E. Young et al.

2001-07-02T23:59:59.000Z

138

Visual Outcome in Meningiomas Around Anterior Visual Pathways Treated With Linear Accelerator Fractionated Stereotactic Radiotherapy  

SciTech Connect

Purpose: Meningiomas threatening the anterior visual pathways (AVPs) and not amenable for surgery are currently treated with multisession stereotactic radiotherapy. Stereotactic radiotherapy is available with a number of devices. The most ubiquitous include the gamma knife, CyberKnife, tomotherapy, and isocentric linear accelerator systems. The purpose of our study was to describe a case series of AVP meningiomas treated with linear accelerator fractionated stereotactic radiotherapy (FSRT) using the multiple, noncoplanar, dynamic conformal rotation paradigm and to compare the success and complication rates with those reported for other techniques. Patients and Methods: We included all patients with AVP meningiomas followed up at our neuro-ophthalmology unit for a minimum of 12 months after FSRT. We compared the details of the neuro-ophthalmologic examinations and tumor size before and after FSRT and at the end of follow-up. Results: Of 87 patients with AVP meningiomas, 17 had been referred for FSRT. Of the 17 patients, 16 completed >12 months of follow-up (mean 39). Of the 16 patients, 11 had undergone surgery before FSRT and 5 had undergone FSRT as first-line management. Tumor control was achieved in 14 of the 16 patients, with three meningiomas shrinking in size after RT. Two meningiomas progressed, one in an area that was outside the radiation field. The visual function had improved in 6 or stabilized in 8 of the 16 patients (88%) and worsened in 2 (12%). Conclusions: Linear accelerator fractionated RT using the multiple noncoplanar dynamic rotation conformal paradigm can be offered to patients with meningiomas that threaten the anterior visual pathways as an adjunct to surgery or as first-line treatment, with results comparable to those reported for other stereotactic RT techniques.

Stiebel-Kalish, Hadas, E-mail: kalishhadas@gmail.com [Neuro-Ophthalmology Unit, Rabin Medical Center, Petah Tikva (Israel); Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Reich, Ehud [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Department of Ophthalmology, Rabin Medical Center, Petah Tikva (Israel); Gal, Lior [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Rappaport, Zvi Harry [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Department of Neurosurgery, Rabin Medical Center, Petah Tikva (Israel); Nissim, Ouzi [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Stereotactic Radiosurgery Unit, Sheba Medical Center, Ramat Gan (Israel); Department of Neurosurgery, Sheba Medical Center, Ramat Gan (Israel); Pfeffer, Raphael [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Stereotactic Radiosurgery Unit, Sheba Medical Center, Ramat Gan (Israel); Spiegelmann, Roberto [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Stereotactic Radiosurgery Unit, Sheba Medical Center, Ramat Gan (Israel); Department of Neurosurgery, Sheba Medical Center, Ramat Gan (Israel)

2012-02-01T23:59:59.000Z

139

Measurements of Neutron Induced Cross Sections at the Oak Ridge Electron Linear Accelerator  

SciTech Connect

We have used the Oak Ridge Electron Linear Accelerator (ORELA) to measure neutron total and the fission cross sections of 233U in the energy range from 0.36 eV to ~700 keV. We report average fission and total cross sections. Also, we measured the neutron total cross sections of 27Al and Natural chlorine as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV.

Guber, K.H.; Harvey, J.A.; Hill, N.W.; Koehler, P.E.; Leal, L.C.; Sayer, R.O.; Spencer, R.R.

1999-09-20T23:59:59.000Z

140

Measurements of Neutron Induced Cross Sections at the Oak Ridge Electron Linear Accelerator  

Science Conference Proceedings (OSTI)

We have used the Oak Ridge Electron Linear Accelerator (ORELA) to measure neutron total and the fission cross sections of 233U in the energy range from 0.36 eV to ~700 keV. We report average fission and total cross sections. Also, we measured the neutron total cross sections of 27Al and Natural chlorine as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV.

Guber, K.H.; Harvey, J.A.; Hill, N.W.; Koehler, P.E.; Leal, L.C.; Sayer, R.O.; Spencer, R.R.

1999-09-20T23:59:59.000Z

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.


141

Report of the ICFA Beam Dynamics Workshop 'Accelerators for a Higgs Factory: Linear vs. Circular' (HF2012)  

E-Print Network (OSTI)

This paper is a summary report of the ICFA Beam Dynamics Workshop 'Accelerators for a Higgs Factory: Linear vs. Circular' (HF2012). It discusses four types of accelerators as possible candidates for a Higgs factory: linear e+e- colliders, circular e+e- colliders, muon collider and photon colliders. The comparison includes: physics reach, performance (energy and luminosity), upgrade potential, technology maturity and readiness, and technical challenges requiring further R&D.

Alain Blondel; Alex Chao; Weiren Chou; Jie Gao; Daniel Schulte; Kaoru Yokoya

2013-02-14T23:59:59.000Z

142

ION ACCELERATOR  

DOE Patents (OSTI)

An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

Bell, J.S.

1959-09-15T23:59:59.000Z

143

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

144

Intraoperative radiation therapy using mobile electron linear accelerators: Report of AAPM Radiation Therapy Committee Task Group No. 72  

Science Conference Proceedings (OSTI)

Intraoperative radiation therapy (IORT) has been customarily performed either in a shielded operating suite located in the operating room (OR) or in a shielded treatment room located within the Department of Radiation Oncology. In both cases, this cancer treatment modality uses stationary linear accelerators. With the development of new technology, mobile linear accelerators have recently become available for IORT. Mobility offers flexibility in treatment location and is leading to a renewed interest in IORT. These mobile accelerator units, which can be transported any day of use to almost any location within a hospital setting, are assembled in a nondedicated environment and used to deliver IORT. Numerous aspects of the design of these new units differ from that of conventional linear accelerators. The scope of this Task Group (TG-72) will focus on items that particularly apply to mobile IORT electron systems. More specifically, the charges to this Task Group are to (i) identify the key differences between stationary and mobile electron linear accelerators used for IORT (ii) describe and recommend the implementation of an IORT program within the OR environment, (iii) present and discuss radiation protection issues and consequences of working within a nondedicated radiotherapy environment, (iv) describe and recommend the acceptance and machine commissioning of items that are specific to mobile electron linear accelerators, and (v) design and recommend an efficient quality assurance program for mobile systems.

Sam Beddar, A.; Biggs, Peter J.; Chang Sha; Ezzell, Gary A.; Faddegon, Bruce A.; Hensley, Frank W.; Mills, Michael D. [Department of Radiation Physics, Division of Radiation Oncology, Unit 94, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599 (United States); Department of Radiation Oncology, Mayo Clinic Scottsdale, Scottsdale, Arizona 85259 (United States); Department of Radiation Oncology, University of California San Francisco, San Francisco, California 94143 (United States); Department of Radiation Oncology, University of Heidelberg, 69120 Heidelberg (Germany); Department of Radiation Oncology, James Graham Brown Cancer Center, Louisville, Kentucky 40202 (United States)

2006-05-15T23:59:59.000Z

145

NON-STANDARD ENERGY SPECTRA OF SHOCK-ACCELERATED SOLAR PARTICLES  

SciTech Connect

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

Kocharov, Leon; Vainio, Rami; Pomoell, Jens [Department of Physics, P.O. Box 64, University of Helsinki, FI-00014 (Finland); Valtonen, Eino [Space Research Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 (Finland); Klassen, Andreas [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet Kiel, D-24118 (Germany); Young, C. Alex [ADNET Systems Inc., NASA Goddard Space Flight Center, Greenbelt, MD 20850 (United States)

2012-07-01T23:59:59.000Z

146

Experimental measurement methods and data on irradiation of functional design materials by helium ions in linear accelerator  

E-Print Network (OSTI)

The experimental research on the irradiation of the functional design materials by the Helium ions in the linear accelerator is conducted. The experimental measurements techniques and data on the irradiation of the functional design materials by the Helium ions with the energy up to 4 MeV, including the detailed scheme of experimental measurements setup, are presented. The new design of accelerating structure of the IH-type such as POS-4, using the method of alternate-phase focusing with the step-by-step change of the synchronous phase along the focusing periods in a linear accelerator, is developed with the aim to irradiate the functional design materials by the Helium ions. The new design of the injector of the charged Helium ions with the energy of 120 KeV at the output of an accelerating tube and the accelerating structure of the type of POS-4 for the one time charged Helium ions acceleration in the linear accelerator are researched and developed. The special chamber for the irradiation of functional design materials by the Helium ions is also created. In the process of experiment, the temperature of a sample, the magnitude of current of Helium ions beam and the irradiation dose of sample are measured precisely. The experimental measurement setup and techniques are fully tested and optimized in the course of the research on the electro-physical properties of irradiated samples and the thermal-desorption of Helium ions in a wide range of temperatures

R. A. Anokhin; V. N. Voyevodin; S. N. Dubnyuk; A. M. Egorov; B. V. Zaitsev; A. F. Kobets; O. P. Ledenyov; K. V. Pavliy; V. V. Ruzhitsky; G. D. Tolstolutskaya

2013-09-03T23:59:59.000Z

147

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

Science Conference Proceedings (OSTI)

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

148

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

149

Load Schedule Coordination for a Large Linear Accelerator: An Operation Powerplay Concept  

E-Print Network (OSTI)

Operation Powerplay is a viable electric load management program developed and tested with Department of Energy funding and support. It is a concept designed to provide financial benefits to a utility and one or more of its customers through priority-based or on-demand load shaving. Currently being implemented in pilot form is a variation of Operation Powerplay. In this instance, it is the mutual cooperation between the Western Area Power Administration (Western), which markets hydro-power from Federal power projects, and the Los Alamos National Laboratory (LANL) at Los Alamos, New Mexico. With this variation, only the portion of LANL's total load requirement for the Linear Accelerator at the Meson Physics Facility is targeted to be managed by this arrangement. This paper will discuss the negotiations and agreements between LANL and Western to maximize use of the Meson facility and minimize operational costs through this variation of Operation Powerplay.

Johnson, W. H.

1984-01-01T23:59:59.000Z

150

Photon beam quality variations of a flattening filter free linear accelerator  

Science Conference Proceedings (OSTI)

Purpose: Recently, there has been an increasing interest in operating conventional linear accelerators without a flattening filter. The aim of this study was to determine beam quality variations as a function of off-axis ray angle for unflattened beams. In addition, a comparison was made with the off-axis energy variation in flattened beams. Methods: Two Elekta Precise linear accelerators were modified in order to enable radiation delivery with and without the flattening filter in the beam line. At the Medical University Vienna (Vienna, Austria), half value layer (HVL) measurements were performed for 6 and 10 MV with an in-house developed device that can be easily mounted on the gantry. At St. Luke's Hospital (Dublin, Ireland), measurements were performed at 6 MV in narrow beam geometry with the gantry tilted around 270 deg. with pinhole collimators, an attenuator, and the chamber positioned on the table. All attenuation measurements were performed with ionization chambers and a buildup cap (2 mm brass) or a PMMA mini phantom (diameter 3 cm, measurement depth 2.5 cm). Results: For flattened 6 and 10 MV photon beams from the Elekta linac the relative HVL({theta}) varies by about 11% for an off-axis ray angle {theta}=10 deg. These results agree within {+-}2% with a previously proposed generic off-axis energy correction. For unflattened beams, the variation was less than 5% in the whole range of off-axis ray angles up to 10 deg. The difference in relative HVL data was less than 1% for unflattened beams at 6 and 10 MV. Conclusions: Off-axis energy variation is rather small in unflattened beams and less than half the one for flattened beams. Thus, ignoring the effect of off-axis energy variation for dose calculations in unflattened beams can be clinically justified.

Georg, Dietmar; Kragl, Gabriele; Wetterstedt, Sacha af; McCavana, Patrick; McClean, Brendan; Knoeoes, Tommy [Department of Radiotherapy, Division Medical Radiation Physics, Medical University of Vienna, AKH Vienna, 1090 Vienna (Austria); Department of Radiotherapy, St Luke's Hospital, Dublin 6 (Ireland); Radiation Physics, Lund University and Lund University Hospital, 22185 Lund (Sweden)

2010-01-15T23:59:59.000Z

151

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

Science Conference Proceedings (OSTI)

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

152

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

Science Conference Proceedings (OSTI)

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

153

Fossil AGN jets as ultra high energy particle accelerators  

E-Print Network (OSTI)

Remnants of AGN jets and their surrounding cocoons leave colossal magnetohydrodynamic (MHD) fossil structures storing total energies ~10^{60} erg. The original active galacic nucleus (AGN) may be dead but the fossil will retain its stable configuration resembling the reversed-field pinch (RFP) encountered in laboratory MHD experiments. In an RFP the longitudinal magnetic field changes direction at a critical distance from the axis, leading to magnetic re-connection there, and to slow decay of the large-scale RFP field. We show that this field decay induces large-scale electric fields which can accelerate cosmic rays with an E^{-2} power-law up to ultra-high energies with a cut-off depending on the fossil parameters. The cut-off is expected to be rigidity dependent, implying the observed composition would change from light to heavy close to the cut-off if one or two nearby AGN fossils dominate. Given that several percent of the universe's volume may house such slowly decaying structures, these fossils may even...

Benford, Gregory

2007-01-01T23:59:59.000Z

154

Fastest Electropolishing Technique on Niobium for Particle Accelerators  

SciTech Connect

Field emission on the inner surfaces of niobium (Nb) superconducting radio frequency (SRF) cavities is still one of the major obstacles for reaching high accelerating gradients for SRF community. Our previous experimental results [1] seemed to imply that the threshold of field emission was related to the thickness of Nb surface oxide layers. In this contribution, a more detailed study on the influences of the surface oxide layers on the field emission on Nb surfaces will be reported. By anodization technique, the thickness of the surface pentoxide layer was artificially fabricated from 3nm up to 460nm. A home-made scanning field emission microscope (SFEM) was employed to perform the scans on the surfaces. Emitters were characterized using a scanning electron microscope together with an energy dispersive x-ray analyzer. The experimental results could be understood by a simple model calculation based on classic electromagnetic theory as shown in Ref.1. Possibly implications for Nb SRF cavity applications from this study will be discussed.

A.T. Wu, S. Jin, R.A. Rimmer, X.Y. Lu, K. Zhao

2011-09-01T23:59:59.000Z

155

Particle Acceleration and Gamma-Ray Production in Shell Remnants  

E-Print Network (OSTI)

A number of nearby Northern Hemisphere shell-type Supernova Remnants (SNRs) has been observed in TeV gamma rays, but none of them could be detected so far. This failure calls for a critical reevaluation of the theoretical arguments for gamma-ray emission of SNRs. The present paper discusses diffusive shock acceleration in shell-type SNRs in full kinetic theory. Emphasis is also given to the possible problems for VHE gamma-ray production due to the environmental conditions a SN progenitor finds itself in. Observational upper limits are compared with theoretical predictions for the gamma-ray flux. Empirical arguments from the observation of X-ray power law continua for electron-induced Inverse Compton gamma-ray emission at TeV energies are discussed in their relation to the nucleonic Pi-zero decay emission from the same objects. Finally, a point is made for the simplest case of SNe Ia, expected to explode in a uniform circumstellar medium. Here in particular the very recently detected Southern Hemisphere remnant of SN 1006 is compared with Tycho's SNR. On the basis of the assumed parameters for the two remnants SN 1006 is tentatively identified with a remnant whose TeV gamma-ray emission is dominated by Inverse Compton radiation. Tycho might be dominantly a Pi-zero decay gamma-ray source.

H. J. Volk

1997-11-18T23:59:59.000Z

156

Stochastic particle acceleration and synchrotron self--Compton radiation in TeV blazars  

E-Print Network (OSTI)

We analyse the influence of the stochastic particle acceleration for the evolution of the electron spectrum. We assume that all investigated spectra are generated inside a spherical, homogeneous source and also analyse the synchrotron and inverse Compton emission generated by such an object. The stochastic acceleration is treated as the diffusion of the particle momentum and is described by the momentum-diffusion equation. We investigate the stationary and time dependent solutions of the equation for several different evolutionary scenarios. The scenarios are divided into two general classes. First, we analyse a few cases without injection or escape of the particles during the evolution. Then we investigate the scenarios where we assume continuous injection and simultaneous escape of the particles. In the case of no injection and escape the acceleration process, competing with the radiative cooling, only modifies the initial particle spectrum. The competition leads to a thermal or quasi-thermal distribution of the particle energy. In the case of the injection and simultaneous escape the resulting spectra depend mostly on the energy distribution of the injected particles. In the simplest case, where the particles are injected at the lowest possible energies, the competition between the acceleration and the escape forms a power-law energy distribution. We apply our modeling to the high energy activity of the blazar Mrk 501 observed in April 1997. Calculating the evolution of the electron spectrum self-consistently we can reproduce the observed spectra well with a number of free parameters that is comparable to or less than in the "classic stationary" one--zone synchrotron self-Compton scenario.

K. Katarzynski; G. Ghisellini; A. Mastichiadis; F. Tavecchio; L. Maraschi

2006-03-14T23:59:59.000Z

157

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

E-Print Network (OSTI)

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

Sadeghi, J; Farahani, H

2013-01-01T23:59:59.000Z

158

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

E-Print Network (OSTI)

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

J. Sadeghi; B. Pourhassan; H. Farahani

2013-10-26T23:59:59.000Z

159

Fossil AGN jets as ultra high energy particle accelerators  

E-Print Network (OSTI)

Remnants of AGN jets and their surrounding cocoons leave colossal magnetohydrodynamic (MHD) fossil structures storing total energies ~10^{60} erg. The original active galacic nucleus (AGN) may be dead but the fossil will retain its stable configuration resembling the reversed-field pinch (RFP) encountered in laboratory MHD experiments. In an RFP the longitudinal magnetic field changes direction at a critical distance from the axis, leading to magnetic re-connection there, and to slow decay of the large-scale RFP field. We show that this field decay induces large-scale electric fields which can accelerate cosmic rays with an E^{-2} power-law up to ultra-high energies with a cut-off depending on the fossil parameters. The cut-off is expected to be rigidity dependent, implying the observed composition would change from light to heavy close to the cut-off if one or two nearby AGN fossils dominate. Given that several percent of the universe's volume may house such slowly decaying structures, these fossils may even re-energize ultra-high energy cosmic rays from distant/old sources, offsetting the ``GZK-losses'' due to interactions with photons of the cosmic microwave background radiation and giving evidence of otherwise undetectable fossils. In this case the composition would remain light to the highest energies if distant sources or fossils dominated, but otherwise would be mixed. It is hoped the new generation of cosmic ray experiments such as the Pierre Auger Observatory and ultra-high energy neutrino telescopes such as ANITA and lunar Cherenkov experiments will clarify this.

Gregory Benford; R. J. Protheroe

2007-06-29T23:59:59.000Z

160

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

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

at those places where particle beams are made to cross. On the other hand, linear accelerators are much easier to build than circular accelerators because they don't need the...

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

A compendium of computer codes used in particle accelerator design and analysis  

Science Conference Proceedings (OSTI)

We present a compilation of computer codes used in the design and analysis of particle accelerators. This document describes each code on a one? or two?page data sheet. All codes included in this compilation are filed at Los Alamos. (AIP)

Los Alamos Accelerator Code Group

1989-01-01T23:59:59.000Z

162

Role of radiation reaction forces in the dynamics of centrifugally accelerated particles  

Science Conference Proceedings (OSTI)

In this paper we study the influence of radiation reaction (RR) forces on the dynamics of centrifugally accelerated particles. It is assumed that the particles move along magnetic field lines anchored in the rotating central object. The common 'bead-on-the-wire' approximation is used. The solutions are found and analyzed for cases when the form of the prescribed trajectory (rigidly rotating field line) is approximated by: (a) straight line, and (b) Archimedes spiral. Dynamics of neutral and charged particles are compared with the emphasis on the role of RR forces in the latter case. It is shown that for charged particles there exist locations of stable equilibrium. It is demonstrated that for particular initial conditions RR forces cause centripetal motion of the particles: their 'falling' on the central rotating object. It is found that in the case of Archimedes spiral both neutral and charged particles can reach infinity where their motion has asymptotically force-free character. The possible importance of these processes for the acceleration of relativistic, charged particles by rotating magnetospheres in the context of the generation of nonthermal, high-energy emission of AGN and pulsars is discussed.

Dalakishvili, G. T.; Rogava, A. D.; Berezhiani, V. I. [Eugene Kharadze Georgian National Astrophysical Observatory, 2a Kazbegi Avenue, Tbilisi-0160(Georgia); Ivane Javakhishvili Tbilisi State University, Faculty of Natural and Exact Sciences, Physics Department, 3, Chavchavadze Avenue, 0128 Tbilisi (Georgia); Centre for Plasma Astrophysics, K.U. Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium) and Abdus Salam International Centre for Theoretical Physics, Trieste I-34014 (Italy); Graduate School of Frontier Sciences, University of Tokyo, 5-1-5-Kashiwanoha, Kashiwa-shi, Chiba 277-8561 (Japan); Institute of Physics, 6 Tamarashvili Street., 0177 Tbilisi (Georgia)

2007-08-15T23:59:59.000Z

163

Non-iterative and exact method for constraining particles in a linear geometry  

E-Print Network (OSTI)

We present a practical numerical method for evaluating the Lagrange multipliers necessary for maintaining a constrained linear geometry of particles in dynamical simulations. The method involves no iterations, and is limited in accuracy only by the numerical methods for solving small systems of linear equations. As a result of the non-iterative and exact (within numerical accuracy) nature of the procedure there is no drift in the constrained geometry, and the method is therefore readily applied to molecular dynamics simulations of, e.g., rigid linear molecules or materials of non-spherical grains. We illustrate the approach through implementation in the commonly used second-order velocity explicit Verlet method.

Horacio Tapia-McClung; Niels Grønbech-Jensen

2004-12-21T23:59:59.000Z

164

ACCELERATION OF PARTICLES AT THE TERMINATION SHOCK OF A RELATIVISTIC STRIPED WIND  

SciTech Connect

The relativistic wind of obliquely rotating pulsars consists of toroidal stripes of opposite magnetic field polarity, separated by current sheets of hot plasma. By means of two- and three-dimensional particle-in-cell simulations, we investigate particle acceleration and magnetic field dissipation at the termination shock of a relativistic striped wind. At the shock, the flow compresses and the alternating fields annihilate by driven magnetic reconnection. Irrespective of the stripe wavelength {lambda} or the wind magnetization {sigma} (in the regime {sigma} >> 1 of magnetically dominated flows), shock-driven reconnection transfers all the magnetic energy of alternating fields to the particles, whose average Lorentz factor increases by a factor of {sigma} with respect to the pre-shock value. The shape of the post-shock spectrum depends primarily on the ratio {lambda}/(r{sub L} {sigma}), where r{sub L} is the relativistic Larmor radius in the wind. The spectrum becomes broader as the value of {lambda}/(r{sub L} {sigma}) increases, passing from a relativistic Maxwellian to a flat power-law tail with slope around -1.5, populated by particles accelerated by the reconnection electric field. Close to the equatorial plane of the wind, where the stripes are symmetric, the highest energy particles resulting from magnetic reconnection can escape ahead of the shock, and be injected into a Fermi-like acceleration process. In the post-shock spectrum, they populate a power-law tail with slope around -2.5, which extends beyond the flat component produced by reconnection. Our study suggests that the spectral break between the radio and the optical band in Pulsar Wind Nebulae can be a natural consequence of particle acceleration at the termination shock of striped pulsar winds.

Sironi, Lorenzo; Spitkovsky, Anatoly, E-mail: lsironi@astro.princeton.edu, E-mail: anatoly@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States)

2011-11-01T23:59:59.000Z

165

Comment on Particle acceleration by stimulated emission of radiation near a solid-state active medium  

Science Conference Proceedings (OSTI)

In a recent Letter, V. Berezovsky, H. Alam, and L. Schaechter have reported 'acceleration of electrons moving in free space near an active Nd:YAG slab'. The reported mechanism is particle acceleration by stimulated emission of radiation (PASER). The energy of electrons was not measured directly, but instead inferred from measurements of the electron beam current, after it 'interacted' with the Nd:YAG slab. In this Comment I suggest that the authors proposition that the increase in beam current being due to the increase in beam energy is incorrect. Let us examine the simplified model of the experiment. The cathode emits about 5 mA of a dc electron beam. The beam is collimated by several apertures to about 100 nA before it reaches the collector, where the absorbed beam current is measured. Between the cathode and the collector this beam is 'continuously illuminated' by photons from the actively pumped optical medium. After the electrons 'absorb' the photons the beam current increases by 30%, to about 130 nA. Firstly, if it were true and if there were no beam collimation, this would have been the violation of charge conservation. Ignoring that fact, the authors suggest that: 'Since the charge density is not expected to vary, the change in the current is due to the increase in the velocity of the electrons.' This statement in itself is incorrect, as it violates the continuity of electron flux: when the beam velocity increases, its density decreases such that the beam current remains constant and the charge is conserved. Indeed, in a dc case (as described in the Letter) the continuity equation reads: d(nv)/dz = 0, where v is the beam velocity, n is the linear charge density and z is the coordinate along the beam axis. Since the dc beam current, I = nv and nv = const from Eq. (1), the dc beam current is not expected to vary with the change in velocity. Since the beam current in the experiment did change, it is obvious that the portion of the beam current, removed by the apertures, cannot be ignored in the analysis as it is the most likely source of the beam current increase. Moreover, there is no evidence whatsoever of the proposed PASER effect in this Letter.

Nagaitsev, Sergei; /Fermilab

2011-05-01T23:59:59.000Z

166

Medical Isotope Production Using A 60 MeV Linear Electron Accelerator , R.C. Block1  

E-Print Network (OSTI)

Medical Isotope Production Using A 60 MeV Linear Electron Accelerator Y. Danon1 , R.C. Block1 , R@rpi.edu) 2 AlphaMed Inc, 20 Juniper Ridge Road, Acton, MA 01720 INTRODUCTION Medical isotopes can be produced

Danon, Yaron

167

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

SciTech Connect

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

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

2011-12-01T23:59:59.000Z

168

EFFECTS OF PERPENDICULAR DIFFUSION ON ENERGETIC PARTICLES ACCELERATED BY THE INTERPLANETARY CORONAL MASS EJECTION SHOCK  

Science Conference Proceedings (OSTI)

In this work, based on a numerical solution of the focused transport equation, we obtained the intensity and anisotropy time profiles of solar energetic particles (SEPs) accelerated by an interplanetary shock in the three-dimensional Parker magnetic field. The shock is treated as a moving source of energetic particles with an assumed particle distribution function. We computed the time profiles of particle flux and anisotropy as measured by an observer at 1 AU, equatorial plane, and various longitudes with respect to the shock propagation direction. With perpendicular diffusion, energetic particles can cross magnetic field lines. Particles may be detected before the observer's field line is connected to the shock. After the observer's field line breaks from the shock front, the observer still can see more particles are injected into its field line. Our simulations show that the particle onset time, peak time, peak intensity, decay rate, and duration of SEP event could be significantly influenced by the effect of perpendicular diffusion. The anisotropy with perpendicular diffusion is almost the same as that without perpendicular diffusion, but there is an obvious difference at the moment when the observer's field line begins to be connected to the shock.

Wang, Y.; Qin, G. [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, M., E-mail: ywang@spaceweather.ac.cn, E-mail: gqin@spaceweather.ac.cn, E-mail: mzhang@fit.edu [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States)

2012-06-10T23:59:59.000Z

169

Electric fields in solar magnetic structures due to gradient driven instabilities: heating and acceleration of particles  

E-Print Network (OSTI)

The electrostatic instabilities driven by the gradients of the density, temperature and magnetic field, are discussed in their application to solar magnetic structures. Strongly growing modes are found for some typical plasma parameters. These instabilities i) imply the presence of electric fields that can accelerate the plasma particles in both perpendicular and parallel directions with respect to the magnetic field vector, and ii) can stochastically heat ions. The perpendicular acceleration is to the leading order determined by the $\\bmath{E}\\times \\bmath{B}$-drift acting equally on both ions and electrons, while the parallel acceleration is most effective on electrons. The experimentally confirmed stochastic heating is shown to act mainly in the direction perpendicular to the magnetic field vector and acts stronger on heavier ions. The energy release rate and heating may exceed for several orders of magnitude the value accepted as necessary for a self-sustained heating in the solar corona. The energy sourc...

Vranjes, J

2009-01-01T23:59:59.000Z

170

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

171

PARTICLE ACCELERATION AT A FLARE TERMINATION SHOCK: EFFECT OF LARGE-SCALE MAGNETIC TURBULENCE  

Science Conference Proceedings (OSTI)

We investigate the acceleration of charged particles (both electrons and protons) at collisionless shocks predicted to exist in the vicinity of solar flares. The existence of standing termination shocks has been examined by flare models and numerical simulations. We study electron energization by numerically integrating the equations of motion of a large number of test-particle electrons in the time-dependent two-dimensional electric and magnetic fields generated from hybrid simulations (kinetic ions and fluid electron) using parameters typical of the solar flare plasma environment. The shock is produced by injecting plasma flow toward a rigid piston. Large-scale magnetic fluctuations-known to exist in plasmas and known to have important effects on the nonthermal electron acceleration at shocks-are also included in our simulations. For the parameters characteristic of the flaring region, our calculations suggest that the termination shock formed in the reconnection outflow region (above post-flare loops) could accelerate electrons to a kinetic energy of a few MeV within 100 ion cyclotron periods, which is of the order of a millisecond. Given a sufficient turbulence amplitude level ({delta}B{sup 2}/B 2{sub 0} {approx} 0.3), about 10% of thermal test-particle electrons are accelerated to more than 15 keV. We find that protons are also accelerated, but not to as high energy in the available time and the energy spectra are considerably steeper than that of the electrons for the parameters used in our simulations. Our results are qualitatively consistent with the observed hard X-ray emissions in solar flares.

Guo Fan; Giacalone, Joe, E-mail: guofan@lpl.arizona.edu [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States)

2012-07-01T23:59:59.000Z

172

EVIDENCE FOR PARTICLE ACCELERATION TO THE KNEE OF THE COSMIC RAY SPECTRUM IN TYCHO'S SUPERNOVA REMNANT  

Science Conference Proceedings (OSTI)

Supernova remnants (SNRs) have long been assumed to be the source of cosmic rays (CRs) up to the 'knee' of the CR spectrum at 10{sup 15} eV, accelerating particles to relativistic energies in their blast waves by the process of diffusive shock acceleration (DSA). Since CR nuclei do not radiate efficiently, their presence must be inferred indirectly. Previous theoretical calculations and X-ray observations show that CR acceleration significantly modifies the structure of the SNR and greatly amplifies the interstellar magnetic field. We present new, deep X-ray observations of the remnant of Tycho's supernova (SN 1572, henceforth Tycho), which reveal a previously unknown, strikingly ordered pattern of non-thermal high-emissivity stripes in the projected interior of the remnant, with spacing that corresponds to the gyroradii of 10{sup 14}-10{sup 15} eV protons. Spectroscopy of the stripes shows the plasma to be highly turbulent on the (smaller) scale of the Larmor radii of TeV energy electrons. Models of the shock amplification of magnetic fields produce structure on the scale of the gyroradius of the highest energy CRs present, but they do not predict the highly ordered pattern we observe. We interpret the stripes as evidence for acceleration of particles to near the knee of the CR spectrum in regions of enhanced magnetic turbulence, while the observed highly ordered pattern of these features provides a new challenge to models of DSA.

Eriksen, Kristoffer A.; Hughes, John P. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States); Badenes, Carles [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Fesen, Robert [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Ghavamian, Parviz [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Moffett, David [Department of Physics, Furman University, Greenville, SC 29613 (United States); Plucinksy, Paul P.; Slane, Patrick [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Rakowski, Cara E. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Reynoso, Estela M. [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina)

2011-02-20T23:59:59.000Z

173

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

SciTech Connect

The Particle-In-Cell (PIC) Code-Framework Warp is being developed by the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) to guide the development of accelerators that can deliver beams suitable for high energy density experiments and implosion of inertial fusion capsules. It is also applied in various areas outside the Heavy Ion Fusion program to the study and design of existing and next-generation high-energy accelerators, including the study of electron cloud effects and laser wakefield acceleration for example. This paper presents an overview of Warp’s capabilities, summarizing recent original numerical methods that were developed by the HIFS-VNL (including Particle-In-Cell with Adaptive Mesh Refinement, a large-timestep “drift-Lorentz” mover for arbitrarily magnetized species, a relativistic Lorentz invariant leapfrog particle pusher, simulations in Lorentz boosted frames, an electromagnetic solver with tunable numerical dispersion and efficient stride20 based digital filtering), with great emphasis on the description of the mesh refinement capability. Selected examples of applications of the methods to the abovementioned fields are given.

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

2011-09-01T23:59:59.000Z

174

acceleration  

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

middle name. The head of Fermilab's Accelerator Division explains a basic idea of high-energy physics in everyday language. Painless Physics Articles BEAM COOLING August 2, 1996...

175

Settlement in an Amereican landscape : a place of work amidst a particle accelerator's transformation of the Texas prarie  

E-Print Network (OSTI)

This thesis considers the design of the research facility accompanying the Superconducting Super Collider, a large particle accelerator planned for central Texas. It will focus on this Pl'Qject as a form of human settlement ...

Falliers, Christopher B. (Christopher Basil)

1991-01-01T23:59:59.000Z

176

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

177

Production and supply of radioisotopes with high-energy particle accelerators current status and future directions  

Science Conference Proceedings (OSTI)

Although the production of radioisotopes in reactors or in low to medium energy cyclotrons appears to be relatively well established, especially for those isotopes that are routinely used and have a commercial market, certain isotopes can either be made only in high-energy particle accelerators or their production is more cost effective when made this way. These facilities are extremely expensive to build and operate, and isotope production is, in general, either not cost-effective or is in conflict with their primary mandate or missions which involve physics research. Isotope production using high-energy accelerators in the US, therefore, has been only an intermittent and parasitic activity. However, since a number of isotopes produced at higher energies are emerging as being potentially useful for medical and other applications, there is a renewed concern about their availability in a continuous and reliable fashion. In the US, in particular, the various aspects of the prediction and availability of radioisotopes from high-energy accelerators are presently undergoing a detailed scrutiny and review by various scientific and professional organizations as well as the Government. A number of new factors has complicated the supply/demand equation. These include considerations of cost versus needs, reliability factors, mission orientation, research and educational components, and commercial viability. This paper will focus on the present status and projected needs of radioisotope production with high-energy accelerators in the US, and will compare and examine the existing infrastructure in other countries for this purpose.

Srivastava, S.C.; Mausner, L.F.

1994-03-01T23:59:59.000Z

178

Testing and Implementation Progress on the Advanced Photon Source (APS) Linear Accelerator (Linac) High-Power S-band Switching System  

E-Print Network (OSTI)

An S-band linear accelerator is the source of particles and the front end of the Advanced Photon Source injector. In addition, it supports a low-energy undulator test line (LEUTL) and drives a free-electron laser (FEL). A waveguide-switching and distribution system is now under construction. The system configuration was revised to be consistent with the recent change to electron-only operation. There are now six modulator-klystron subsystems, two of which are being configured to act as hot spares for two S-band transmitters each, so that no single failure will prevent injector operation. The two subsystems are also used to support additional LEUTL capabilities and off-line testing. Design considerations for the waveguide-switching subsystem, topology selection, control and protection provisions, high-power test results, and current status are described

Grelick, A E; Berg, S; Dohan, D A; Goeppner, G A; Kang, Y W; Nassiri, A; Pasky, S; Pile, G; Smith, T; Stein, S J

2000-01-01T23:59:59.000Z

179

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

Science Conference Proceedings (OSTI)

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

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

2012-09-15T23:59:59.000Z

180

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

Science Conference Proceedings (OSTI)

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

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

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

182

Improving the design and analysis of superconducting magnets for particle accelerators  

Science Conference Proceedings (OSTI)

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

183

Accelerator  

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

1. ACCELERATOR PHYSICS OF COLLIDERS Revised July 2011 by D. A. Edwards (DESY) and M. J. Syphers (MSU) 1.1. Luminosity This article provides background for the High-Energy Collider...

184

Thin current sheets in collisionless plasma: Equilibrium structure, plasma instabilities, and particle acceleration  

Science Conference Proceedings (OSTI)

The review is devoted to plasma structures with an extremely small transverse size, namely, thin current sheets that have been discovered and investigated by spacecraft observations in the Earth's magnetotail in the last few decades. The formation of current sheets is attributed to complicated dynamic processes occurring in a collisionless space plasma during geomagnetic perturbations and near the magnetic reconnection regions. The models that describe thin current structures in the Earth's magnetotail are reviewed. They are based on the assumption of the quasi-adiabatic ion dynamics in a relatively weak magnetic field of the magnetotail neutral sheet, where the ions can become unmagnetized. It is shown that the ion distribution can be represented as a function of the integrals of particle motion-the total energy and quasi-adiabatic invariant. Various modifications of the initial equilibrium are considered that are obtained with allowance for the currents of magnetized electrons, the contribution of oxygen ions, the asymmetry of plasma sources, and the effects related to the non-Maxwellian particle distributions. The theoretical results are compared with the observational data from the Cluster spacecraft mission. Various plasma instabilities developing in thin current sheets are investigated. The evolution of the tearing mode is analyzed, and the parameter range in which the mode can grow are determined. The paradox of complete stabilization of the tearing mode in current sheets with a nonzero normal magnetic field component is thereby resolved based on the quasi-adiabatic model. It is shown that, over a wide range of current sheet parameters and the propagation directions of large-scale unstable waves, various modified drift instabilities-kink and sausage modes-can develop in the system. Based on the concept of a turbulent electromagnetic field excited as a result of the development and saturation of unstable waves, a mechanism for charged particle acceleration in turbulent current sheets is proposed and the energy spectra of the accelerated particles are obtained.

Zelenyi, L. M.; Malova, H. V.; Artemyev, A. V.; Popov, V. Yu.; Petrukovich, A. A. [Russian Academy of Sciences, Space Research Institute (Russian Federation)

2011-02-15T23:59:59.000Z

185

Advanced Laser Particle Accelerator Development at LANL: From Fast Ignition to Radiation Oncology  

Science Conference Proceedings (OSTI)

Laser-plasma accelerated ion and electron beam sources are an emerging field with vast prospects, and promise many superior applications in a variety of fields such as hadron cancer therapy, compact radioisotope generation, table-top nuclear physics, laboratory astrophysics, nuclear forensics, waste transmutation, Special Nuclear Material (SNM) detection, and inertial fusion energy. LANL is engaged in several projects seeking to develop compact high-current and high-energy ion and electron sources. We are especially interested in two specific applications: ion fast ignition/capsule perturbation and radiation oncology. Laser-to-beam conversion efficiencies of over 10% are needed for practical applications, and we have already shown inherent efficiencies of >5% from flat foils, on Trident using only a 5th of the intensity and energy of the Nova Petawatt laser. With clever target designs, like structured curved cone targets, we have also been able to achieve major ion energy gains, leading to the highest energy laser-accelerated proton beams in the world [3]. These new target designs promise to help usher in the next generation of particle sources realizing the potential of laser-accelerated beams.

Flippo, K. A.; Offermann, D. T.; Cobble, J. A.; Schmitt, M. J.; Gautier, D. C.; Kwan, T. J.; Montgomery, D. S. [Los Alamos National Laboratory, PO BOX 1663, Los Alamos, NM 87545 (United States); Gaillard, S. A.; Kluge, T.; Bussmann, M.; Cowan, T. E. [ForschungsZentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Bartal, T.; Beg, F. N. [University of California, San Diego, Mechanical and Aerospace Engineering Dept., La Jolla, CA 92038 (United States); Gall, B.; Kovaleski, S. [University of Missouri, Electrical and Computer Engineering, Columbia MO 65211 (United States); Geissel, M.; Schollmeier, M. [Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185 (United States); Korgan, G.; Malekos, S. [Nanolabz, 661 Sierra Rose Dr., Reno, NV 89511 (United States); Lockard, T. [University of Nevada, Physics, Reno, NV 89557 (United States)

2010-11-04T23:59:59.000Z

186

The relevance of particle flux monitors in accelerator-based activation analysis  

SciTech Connect

One of the most critical parameters in activation analysis is the flux density of the activating radiation, its spatial distribution in particular. The validity of the basic equation for calculating the activity induced to the exposed item depends upon the fulfilment of several conditions, the most relevant of them being equal doses of incident activating radiation received by the unknown sample, the calibration material and the reference material, respectively. This requirement is most problematic if accelerator-produced radiation is used for activation. Whilst nuclear research reactors usually are equipped with exposure positions that provide fairly homogenous activation fields for thermal neutron activation analysis accelerator-generated particle beams (neutrons, photons, charged particles) usually exhibit axial and, in particular, sharp radial flux gradients. Different experimental procedures have been developed to fulfil the condition mentioned above. In this paper, three variants of the application of flux monitors in photon activation analysis are discussed (external monitor, additive and inherent internal monitor). Experiments have indicated that the latter technique yields highest quality of the analytical results.

Segebade, Chr.; Maimaitimin, M.; Sun Zaijing [Idaho Accelerator Centre, Idaho State University, 1500 Alvin Ricken Drive, Pocatello, ID 83201 (United States)

2013-04-19T23:59:59.000Z

187

Accelerator Need  

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

Need for Large Accelerators An Article Written Originally for Midlevel Teachers Back In order to study small particles, a high energy beam of particles must be generated. The...

188

Experimental study of new laser-based alignment system at the KEK B-factory injector linear accelerator  

Science Conference Proceedings (OSTI)

A new laser-based alignment system for the precise alignment of accelerator components along an ideal straight line at the KEK B-factory injector linear accelerator (linac) is under development. This system is strongly required in the next generation of B-factories for the stable acceleration of high-brightness electron and positron beams with high bunch charges and also for maintaining the stability of injection beams with high quality. A new laser optics for the generation of a so-called Airy beam has been developed for the laser-based alignment system. The laser propagation characteristics both in vacuum and at atmospheric pressure have been systematically investigated in an 82-m-long straight section of the injector linac. The laser-based alignment measurements based on the new laser optics have been carried out with a measurement resolution of {+-}0.1 mm level by using an existing laser detection electronics. The horizontal and vertical displacements from a reference laser line measured using this system are in good agreement with those measured using a standard telescope-based optical alignment technique. In this report, we describe the experimental study in detail along with the basic designs and the recent developments in the new laser-based alignment system.

Suwada, T.; Satoh, M.; Kadokura, E. [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

2010-12-15T23:59:59.000Z

189

SLAC National Accelerator Laboratory - Accelerators and Society  

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

Accelerators and Society PHOTO: An accelerator at SLAC. SLAC has been developing, running and studying the basic physics of particle accelerators for half a century. Thousands of...

190

A Non-interceptive Method to Measure Longitudinal Twiss Parameters of a Beam in a Hadron Linear Accelerator using Beam Position Monitors  

Science Conference Proceedings (OSTI)

A new method of measuring of the RMS longitudinal Twiss parameters of a beam in linear accelerators is presented. It is based on using signals from beam position monitors (BPM) sensitive to the second order moment of 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 (SNS) linear accelerator. The results are compared to a direct measurement of the bunch longitudinal profiles using an interceptive bunch shape monitor (BSM) 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.

Aleksandrov, Alexander V [ORNL; Shishlo, Andrei P [ORNL

2013-01-01T23:59:59.000Z

191

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

192

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

Science Conference Proceedings (OSTI)

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

Sarri, G.; Kourakis, I.; Borghesi, M. [Centre for Plasma Physics, The Queen's University of Belfast, Belfast BT7 1NN (United Kingdom); Dieckmann, M. E. [VITA ITN, Linkoping University, 60174 Norrkoping (Sweden)

2010-08-15T23:59:59.000Z

193

Radio frequency pulse compression experiments at SLAC (Stanford Linear Accelerator Center)  

Science Conference Proceedings (OSTI)

Proposed future positron-electron linear colliders would be capable of investigating fundamental processes of interest in the 0.5--5 TeV beam-energy range. At the SLAC Linear Collider (SLC) gradient of about 20 MV/m this would imply prohibitive lengths of about 50--250 kilometers per linac. We can reduce the length by increasing the gradient but this implies high peak power, on the order of 400-- to 1000-MW at X-Band. One possible way to generate high peak power is to generate a relatively long pulse at a relatively low power and compress it into a short pulse with higher peak power. It is possible to compress before DC to RF conversion, as is done using magnetic switching for induction linacs, or after DC to RF conversion, as is done for the SLC. Using RF pulse compression it is possible to boost the 50-- to 100-MW output that has already been obtained from high-power X-Band klystrons the levels required by the linear colliders. In this note only radio frequency pulse compression (RFPC) is considered.

Farkas, Z.D.; Lavine, T.L.; Menegat, A.; Miller, R.H.; Nantista, C.; Spalek, G.; Wilson, P.B.

1991-01-01T23:59:59.000Z

194

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

SciTech Connect

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, M.J.; McCarthy, D.W.; Shefer, R.E.; Klinkowstein, R.E.

2000-01-04T23:59:59.000Z

195

DEVELOPMENTS IN ACCELERATORS AND INSTRUMENTATION RELEVANT TO IMAGING WITH CHARGED PARTICLES AND POSITRON EMITTERS  

E-Print Network (OSTI)

IN ACCELERATORS AND INSTRUMENTATION RELEVANT TO IMAGING WITHin Accelerators and Instrumentation Relevant to Imaging withto develop necessary instrumentation and techniques for the

Alonso, J.R.

2010-01-01T23:59:59.000Z

196

Measurement of the neutron leakage from a dedicated intraoperative radiation therapy electron linear accelerator and a conventional linear accelerator for 9, 12, 15(16), and 18(20) MeV electron energies  

SciTech Connect

The issue of neutron leakage has recently been raised in connection with dedicated electron-only linear accelerators used for intraoperative radiation therapy (IORT). In particular, concern has been expressed about the degree of neutron production at energies of 10 MeV and higher due to the need for additional, perhaps permanent, shielding in the room in which the device is operated. In particular, three mobile linear accelerators available commercially offer electron energies at or above the neutron threshold, one at 9 MeV, one at 10 MeV, and the third at 12 MeV. To investigate this problem, neutron leakage has been measured around the head of two types of electron accelerators at a distance of 1 m from the target at azimuthal angles of 0 deg., 45 deg., 90 deg., 135 deg., and 180 deg. The first is a dedicated electron-only (nonmobile) machine with electron energies of 6 (not used here), 9, 12, 15, and 18 MeV and the second a conventional machine with electron energies of 6 (also not used here), 9, 12, 16, and 20 MeV. Measurements were made using neutron bubble detectors and track-etch detectors. For electron beams from a conventional accelerator, the neutron leakage in the forward direction in Sv/Gy is 2.1x10{sup -5} at 12 MeV, 1.3x10{sup -4} at 16 MeV, and 4.2x10{sup -4} at 20 MeV, assuming a quality factor (RBE) of 10. For azimuthal angles >0 deg., the leakage is almost angle independent [2x10{sup -6} at 12 MeV; (0.7-1.6)x10{sup -5} at 16 MeV, and (1.6-2.9)x10{sup -5} at 20 MeV]. For the electron-only machine, the neutron leakage was lower than for the conventional linac, but also independent of azimuthal angle for angles >0 deg. : ([0 deg. : 7.7x10{sup -6} at 12 MeV; 3.0x10{sup -5} at 15 MeV; 1.0x10{sup -4} at 18 MeV]; [other angles: (2.6-5.9)x10{sup -7} at 12 MeV; (1.4-2.2)x10{sup -6} at 15 MeV; (2.7-4.7)x10{sup -6} at 18 MeV]). Using the upper limit of 6x10{sup -7} Sv/Gy at 12 MeV for the IORT machine for azimuthal angles >0 deg. and assuming a workload of 200 Gy/wk and an inverse square factor of 10, the neutron dose equivalent is calculated to be 0.012 mSv/wk. For the primary beam at 12 MeV (0 deg. ), the 10x higher dose would be compensated by the attenuation of a primary beam stopper in a mobile linear accelerator. These neutron radiation levels are below regulatory values (National Council on Radiation Protection and Measurements, 'Limitation of exposure to ionizing radiation', NCRP Report No. 116, NCRP Bethesda, MD, 1993)

Jaradat, Adnan K.; Biggs, Peter J. [Department of Physics, University of Massachusetts Lowell, One University Avenue, Lowell, Massachusetts 01854 (United States); Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114 (United States)

2008-05-15T23:59:59.000Z

197

Focusing solenoid for the front end of a linear RF accelerator  

SciTech Connect

A prototype of a superconducting focusing solenoid for use in an RF linac has been built and tested at Fermi National Accelerator Laboratory (FNAL). The solenoid is comprised of the main coil, two bucking coils, two dipole corrector windings, and a low carbon steel flux return. At the excitation current of 250 A, the magnetic field reaches 7.2 T in the center of the solenoid and is less than 5 G on the axis at a distance of 150 mm from the center. The length of the solenoid is 150 mm; the length of a cryovessel for the solenoid with a 20 mm diameter 'warm' bore is 270 mm. This paper presents the main design features of the focusing solenoid and discusses results from tests of the solenoid.

Terechkine, I.; Kashikhin, V.V.; Page, T.; Tartaglia, M.; Tompkins, J.; /Fermilab

2007-06-01T23:59:59.000Z

198

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

Science Conference Proceedings (OSTI)

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

Gong Chunye, E-mail: gongchunye@gmail.com [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Liu Jie, E-mail: liujie@nudt.edu.cn [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Chi Lihua [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Huang Haowei [Institut fuer Informatik, Technische Universitaet Muenchen, D-85748 Garching, Munich (Germany); Fang Jingyue [School of Physics and Mathematics, National University of Defense Technology, Changsha 410073 (China); Gong Zhenghu [School of Computer Science, National University of Defense Technology, Changsha 410073 (China)

2011-07-01T23:59:59.000Z

199

Suppressing Thermal Energy Drift In The LLNL Flash X-Ray Accelerator Using Linear Disk Resistor Stacks  

SciTech Connect

This paper addresses thermal drift in sodium thiosulfate liquid resistors and their replacement with linear disk resistors from HVR Advanced Power Components. Sodium thiosulfate resistors in the FXR induction linear accelerator application have a temperature coefficient of {approx}1.8%/C. The FXR Marx banks send an 8kJ pulse through eight 524 cm{sup 3} liquid resistors at a repetition rate of up to 1 every 45 seconds. Every pulse increases the temperature of the solution by {approx}0.4 C which produces a 0.7% change in resistance. The typical cooling rate is {approx}0.4 C per minute which results in {approx}0.1% energy drop per pulse during continuous pulsed operations. A radiographic accelerator is extraordinarily sensitive to energy variations. Changes in beam energy produce movement in beam transport, changes in spot size, and large dose variations. If self-heating were the only problem, we could predict the increase in input voltage required to compensate for the energy loss. However, there are other variables that influence the temperature of the resistors such as focus magnet heating, changes in room temperature, changes in cooling water, where the cell is located, etc. Additionally not all of the resistors have equivalent cooling rates and as many as 32 resistors are driven from a single power source. The FXR accelerator group elected to replace the sodium thiosulfate resistors with HVR Linear Disk Resistors in a stack type configuration. With data limited for these resistors when used in oil and at low resistance values, a full characterization needed to be performed. High currents (up to 15kA), high voltages (up to 400kV), and Fast Rise times (<10ns) made a resistor choice difficult. Other solid resistors have been tried and had problems at the connection points and with the fact that the resistivity changed as they absorbed oil. The selected HVR resistors have the advantage of being manufactured with the oil impregnated in to them so this characteristic is minimized while still offering the desired low temperature coefficient of resistance compared to sodium thiosulfate. The characterization experiments and comparison with the sodium thiosulfate liquid resistors will be fully discussed and the final design described.

Kreitzer, B R; Houck, T L; Luchterhand, O C

2011-07-19T23:59:59.000Z

200

New results on particle acceleration in the Centaurus A jet and counterjet from a deep Chandra observation  

E-Print Network (OSTI)

We present new deep Chandra observations of the Centaurus A jet, with a combined on-source exposure time of 719 ks. These data allow detailed X-ray spectral measurements to be made along the jet out to its disappearance at 4.5 kpc from the nucleus. We distinguish several regimes of high-energy particle acceleration: while the inner part of the jet is dominated by knots and has properties consistent with local particle acceleration at shocks, the particle acceleration in the outer 3.4 kpc of the jet is likely to be dominated by an unknown distributed acceleration mechanism. In addition to several compact counterjet features we detect probable extended emission from a counterjet out to 2.0 kpc from the nucleus, and argue that this implies that the diffuse acceleration process operates in the counterjet as well. A preliminary search for X-ray variability finds no jet knots with dramatic flux density variations, unlike the situation seen in M87.

M. J. Hardcastle; R. P. Kraft; G. R. Sivakoff; J. L. Goodger; J. H. Croston; A. Jordan; D. A. Evans; D. M. Worrall; M. Birkinshaw; S. Raychaudhury; N. J. Brassington; W. R. Forman; W. E. Harris; C. Jones; A. M. Juett; S. S. Murray; P. E. J. Nulsen; C. L. Sarazin; K. A. Woodley

2007-10-05T23:59:59.000Z

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.


201

Neutron-induced electronic failures around a high-energy linear accelerator  

Science Conference Proceedings (OSTI)

Purpose: After a new in-vault CT-on-rails system repeatedly malfunctioned following use of a high-energy radiotherapy beam, we investigated the presence and impact of neutron radiation on this electronic system, as well as neutron shielding options. Methods: We first determined the CT scanner's failure rate as a function of the number of 18 MV monitor units (MUs) delivered. We then re-examined the failure rate with both 2.7-cm-thick and 7.6-cm-thick borated polyethylene (BPE) covering the linac head for neutron shielding. To further examine shielding options, as well as to explore which neutrons were relevant to the scanner failure, Monte Carlo simulations were used to calculate the neutron fluence and spectrum in the bore of the CT scanner. Simulations included BPE covering the CT scanner itself as well as covering the linac head. Results: We found that the CT scanner had a 57% chance of failure after the delivery of 200 MUs. While the addition of neutron shielding to the accelerator head reduced this risk of failure, the benefit was minimal and even 7.6 cm of BPE was still associated with a 29% chance of failure after the delivery of 200 MU. This shielding benefit was achieved regardless of whether the linac head or CT scanner was shielded. Additionally, it was determined that fast neutrons were primarily responsible for the electronic failures. Conclusions: As illustrated by the CT-on-rails system in the current study, physicists should be aware that electronic systems may be highly sensitive to neutron radiation. Medical physicists should therefore monitor electronic systems that have not been evaluated for potential neutron sensitivity. This is particularly relevant as electronics are increasingly common in the therapy vault and newer electronic systems may exhibit increased sensitivity.

Kry, Stephen F.; Johnson, Jennifer L.; White, R. Allen; Howell, Rebecca M.; Kudchadker, Rajat J.; Gillin, Michael T. [Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 and Health Science Center Houston, Graduate School of Biomedical Sciences, University of Texas Health Science Center Houston, Houston, Texas 77030 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Department of Biostatistics and Applied Mathematics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States) and Health Science Center Houston, Graduate School of Biomedical Sciences, University of Texas, Houston, Texas 77030 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States) and Health Science Center Houston, Graduate School of Biomedical Sciences, University of Texas, Houston, Texas 77030 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States)

2011-01-15T23:59:59.000Z

202

Construction of symplectic maps for nonlinear motion of particles in accelerators  

Science Conference Proceedings (OSTI)

We explore an algorithm for the construction of symplectic maps to describe nonlinear particle motion in circular accelerators. We emphasize maps for motion over one or a few full turns, which may provide an economical way of studying long-term stability in large machines such as the Superconducting Super Collider (SSC). The map is defined implicitly by a mixed-variable generating function, represented as a Fourier series in betatron angle variables, with coefficients given as [ital B]-spline functions of action variables and the total energy. Despite the implicit definition, iteration of the map proves to be a fast process. The method is illustrated with a realistic model of the SSC. We report extensive tests of accuracy and iteration time in various regions of phase space, and demonstrate the results by using single-turn maps to follow trajectories symplectically for 10[sup 7] turns on a workstation computer. The same method may be used to construct the Poincare map of Hamiltonian systems in other fields of physics.

Berg, J.S.; Warnock, R.L.; Ruth, R.D. (Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)); Forest, E. (Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States))

1994-01-01T23:59:59.000Z

203

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

Science Conference Proceedings (OSTI)

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

204

Three dimensional particle-in-cell simulation of particle acceleration by circularly polarised inertial Alfven waves in a transversely inhomogeneous plasma  

SciTech Connect

The process of particle acceleration by left-hand, circularly polarised inertial Alfven waves (IAW) in a transversely inhomogeneous plasma is studied using 3D particle-in-cell simulation. A cylindrical tube with, transverse to the background magnetic field, inhomogeneity scale of the order of ion inertial length is considered on which IAWs with frequency 0.3{omega}{sub ci} are launched that are allowed to develop three wavelength. As a result time-varying parallel electric fields are generated in the density gradient regions which accelerate electrons in the parallel to magnetic field direction. Driven perpendicular electric field of IAWs also heats ions in the transverse direction. Such numerical setup is relevant for solar flaring loops and earth auroral zone. This first, 3D, fully kinetic simulation demonstrates electron acceleration efficiency in the density inhomogeneity regions, along the magnetic field, of the order of 45% and ion heating, in the transverse to the magnetic field direction, of 75%. The latter is a factor of two times higher than the previous 2.5D analogous study and is in accordance with solar flare particle acceleration observations. We find that the generated parallel electric field is localised in the density inhomogeneity region and rotates in the same direction and with the same angular frequency as the initially launched IAW. Our numerical simulations seem also to suggest that the 'knee' often found in the solar flare electron spectra can alternatively be interpreted as the Landau damping (Cerenkov resonance effect) of IAWs due to the wave-particle interactions.

Tsiklauri, D. [Astronomy Unit, School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

2012-08-15T23:59:59.000Z

205

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

206

Laser Guiding at Relativistic Intensities and Wakefield Particle Acceleration in Plasma Channels  

E-Print Network (OSTI)

pulsed, THz radiation from laser accelerated relativisticGuiding of Relativistic Laser Pulses by Plasma Channels,"Wake Fields by Colliding Laser Pulses,"Phys. Rev. Lett.

2005-01-01T23:59:59.000Z

207

University, Linear Accelerator  

E-Print Network (OSTI)

proposals for innovative, econanical, low head hydro power plant ides development. For this purpose, low head was defined as 3m or less. Early hydra power projects were small scale and very close to load centers. Inefficient paddlewheels turned shafts in udlls which, through belts, drove mill equipmt. With the advent of electrical wr, hydro power projects could be reasonably rarote from load centers and located at optimm sites of high head and intermediate flew or high flow and intermediate head. The best sites were quickly exploited and secondary sites became uneconanical. Secondary sites or those evenmre rmte fran load centers were then erploitedby public agencies and the ec onanics justified by power generation plus flood control and/or irrigation plus establistrnent of potable water reservoirs, to serve rapidly growing urban centers. Many of the earlier dams no longer were used to generate power as the mill-races vanished. Many nw low head dams were used for flood control and evening flows toward hydro ver ejects, and were not furnished with generators since these sites were even m3re rarPte

F. F. -hall; P. Box

1980-01-01T23:59:59.000Z

208

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.

209

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

210

Dense Plasma Focus Z-pinches for High Gradient Particle Acceleration  

SciTech Connect

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

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

2009-07-24T23:59:59.000Z

211

Factors Predictive of Symptomatic Radiation Injury After Linear Accelerator-Based Stereotactic Radiosurgery for Intracerebral Arteriovenous Malformations  

SciTech Connect

Purpose: To investigate predictive factors in the development of symptomatic radiation injury after treatment with linear accelerator-based stereotactic radiosurgery for intracerebral arteriovenous malformations and relate the findings to the conclusions drawn by Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC). Methods and Materials: Archived plans for 73 patients who were treated at the British Columbia Cancer Agency were studied. Actuarial estimates of freedom from radiation injury were calculated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used for analysis of incidence of radiation injury. Log-rank test was used to search for dosimetric parameters associated with freedom from radiation injury. Results: Symptomatic radiation injury was exhibited by 14 of 73 patients (19.2%). Actuarial rate of symptomatic radiation injury was 23.0% at 4 years. Most patients (78.5%) had mild to moderate deficits according to Common Terminology Criteria for Adverse Events, version 4.0. On univariate analysis, lesion volume and diameter, dose to isocenter, and a V{sub x} for doses {>=}8 Gy showed statistical significance. Only lesion diameter showed statistical significance (p < 0.05) in a multivariate model. According to the log-rank test, AVM volumes >5 cm{sup 3} and diameters >30 mm were significantly associated with the risk of radiation injury (p < 0.01). The V{sub 12} also showed strong association with the incidence of radiation injury. Actuarial incidence of radiation injury was 16.8% if V{sub 12} was <28 cm{sup 3} and 53.2% if >28 cm{sup 3} (log-rank test, p = 0.001). Conclusions: This study confirms that the risk of developing symptomatic radiation injury after radiosurgery is related to lesion diameter and volume and irradiated volume. Results suggest a higher tolerance than proposed by QUANTEC. The widely differing findings reported in the literature, however, raise considerable uncertainties.

Herbert, Christopher, E-mail: cherbert@bccancer.bc.ca [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Moiseenko, Vitali [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); McKenzie, Michael [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Redekop, Gary [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Hsu, Fred [Department of Radiation Oncology, British Columbia Cancer Agency, Abbotsford, BC (Canada); Gete, Ermias; Gill, Brad; Lee, Richard; Luchka, Kurt [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); Haw, Charles [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Lee, Andrew [Department of Neurosurgery, Royal Columbian Hospital, New Westminster, BC (Canada); Toyota, Brian [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Martin, Montgomery [Department of Medical Imaging, British Columbia Cancer Agency, Vancouver, BC (Canada)

2012-07-01T23:59:59.000Z

212

Modeling laser wakefield accelerator experiments with ultrafast particle-in-cell simulations in boosted frames  

Science Conference Proceedings (OSTI)

The development of new laser systems at the 10 Petawatt range will push laser wakefield accelerators to novel regimes, for which theoretical scalings predict the possibility to accelerate electron bunches up to tens of GeVs in meter-scale plasmas. Numerical simulations will play a crucial role in testing, probing, and optimizing the physical parameters and the setup of future experiments. Fully kinetic simulations are computationally very demanding, pushing the limits of today's supercomputers. In this paper, the recent developments in the OSIRIS framework [R. A. Fonseca et al., Lect. Notes Comput. Sci. 2331, 342 (2002)] are described, in particular the boosted frame scheme, which leads to a dramatic change in the computational resources required to model laser wakefield accelerators. Results from one-to-one modeling of the next generation of laser systems are discussed, including the confirmation of electron bunch acceleration to the energy frontier.

Martins, S. F.; Fonseca, R. A.; Vieira, J.; Silva, L. O. [GoLP/Instituto de Plasmas e Fusao Nuclear-Laboratorio Associado, Instituto Superior Tecnico, Lisbon (Portugal); Lu, W.; Mori, W. B. [University of California Los Angeles, Los Angeles, California 90095 (United States)

2010-05-15T23:59:59.000Z

213

Performances Analysis of Main Components Used in 60 MW Pulsed Supply for Particle Accelerator  

E-Print Network (OSTI)

The Proton-Synchrotron (PS) accelerator at CERN will be supplied by a new power system. The pulsed operation of the PS accelerator requires a specific design of the main components of the power system. This paper presents some key elements of the design of DC/DC power converters in terms of aging of power semiconductors, the strategy of harmonics voltage suppression and the design of the output filters. Finally, the performance of this new power system is presented.

Peron, R; Pouliquen, JL; Gollentz, B; Bordry, F; Burnet, JP

2010-01-01T23:59:59.000Z

214

THE NON-LINEAR THEORY OF ELEMENTARY PARTICLES. Discussions led by W. Heisenberg  

SciTech Connect

A transcript is given of a recorded discussion of t he nonlinear theory of elementary particles; which was held at the University of Rochester in August 1960, at the close of a seminar on "Theoriss of Elementary Particles." (B.O.G.)

1961-02-27T23:59:59.000Z

215

(Theory of elementary particles studies in weak interaction and grand unification and studies in accelerator design)  

Science Conference Proceedings (OSTI)

This report discusses research on: Stanford linear collider detector; Mark II; GEM; tau-charm factory; and SECC preradiator prototype and beam test. (LSP)

Not Available

1991-01-01T23:59:59.000Z

216

THREE-DIMENSIONAL SIMULATIONS OF THE THERMAL X-RAY EMISSION FROM YOUNG SUPERNOVA REMNANTS INCLUDING EFFICIENT PARTICLE ACCELERATION  

Science Conference Proceedings (OSTI)

Supernova remnants (SNRs) are believed to be the major contributors to Galactic cosmic rays. The detection of non-thermal emission from SNRs demonstrates the presence of energetic particles, but direct signatures of protons and other ions remain elusive. If these particles receive a sizeable fraction of the explosion energy, the morphological and spectral evolution of the SNR must be modified. To assess this, we run three-dimensional hydrodynamic simulations of a remnant coupled with a nonlinear acceleration model. We obtain the time-dependent evolution of the shocked structure, impacted by the Rayleigh-Taylor hydrodynamic instabilities at the contact discontinuity and by the back-reaction of particles at the forward shock. We then compute the progressive temperature equilibration and non-equilibrium ionization state of the plasma, and its thermal emission in each cell. This allows us to produce the first realistic synthetic maps of the projected X-ray emission from the SNR. Plasma conditions (temperature and ionization age) can vary widely over the projected surface of the SNR, especially between the ejecta and the ambient medium owing to their different composition. This demonstrates the need for spatially resolved spectroscopy. We find that the integrated emission is reduced with particle back-reaction, with the effect being more significant for the highest photon energies. Therefore, different energy bands, corresponding to different emitting elements, probe different levels of the impact of particle acceleration. Our work provides a framework for the interpretation of SNR observations with current X-ray missions (Chandra, XMM-Newton, and Suzaku) and with upcoming X-ray missions (such as Astro-H).

Ferrand, Gilles; Safi-Harb, Samar [Department of Physics and Astronomy, University of Manitoba, Winnipeg MB R3T 2N2 (Canada); Decourchelle, Anne, E-mail: gferrand@physics.umanitoba.ca, E-mail: samar@physics.umanitoba.ca, E-mail: anne.decourchelle@cea.fr [Laboratoire AIM (CEA/Irfu, CNRS/INSU, Universite Paris VII), CEA Saclay, bat. 709, F-91191 Gif sur Yvette (France)

2012-11-20T23:59:59.000Z

217

Physics Out Loud - Particle Resonance  

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

Particle Accelerator Previous Video (Particle Accelerator) Physics Out Loud Main Index Next Video (Photomultiplier Tube) Photomultiplier Tube Particle Resonance How is a particle...

218

Transmutation of high-level radioactive waste by a charged particle accelerator  

SciTech Connect

Transmutation of minor actinides and fission products using proton accelerators has many advantages over a transmutor operated in a critical condition. The energy required for this transmutation can be reduced by multiplying the spallation neutrons in a subcritical assembly surrounding the spallation target. The authors have studied the relation between the energy requirements and the multiplication factor, k, of the subcritical assembly, while varying the range of several parameters in the spallation target. A slightly subcritical reactor is superior to a reactor with large subcriticality in the context of the energy requirement of a small proton accelerator, the extent of radiation damage, and other safety problems. To transmute the fission products, the transmutor reactor must have a good neutron economy, which can be provided by a transmutor operated by a proton accelerator. The paper discusses the use of minor actinides to improve neutronics characteristics, such as a long fuel burn-up rather than simply transmuting this valuable material.

Takahashi, Hiroshi

1993-12-31T23:59:59.000Z

219

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

220

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

Science Conference Proceedings (OSTI)

Graphics Processing Unit (GPU), originally developed for real-time, high-definition 3D graphics in computer games, now provides great faculty in solving scientific applications. The basis of particle transport simulation is the time-dependent, multi-group, ... Keywords: CUDA, Discrete ordinates (Sn) method, GPU, Particle transport, Sweep3D

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

2011-07-01T23:59:59.000Z

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.


221

Towards accelerating smoothed particle hydrodynamics simulations for free-surface flows on multi-GPU clusters  

Science Conference Proceedings (OSTI)

Starting from the single graphics processing unit (GPU) version of the Smoothed Particle Hydrodynamics (SPH) code DualSPHysics, a multi-GPU SPH program is developed for free-surface flows. The approach is based on a spatial decomposition technique, whereby ... Keywords: CUDA, Computational fluid dynamics, GPU, Graphics processing unit, Molecular dynamics, Multi-GPU, SPH, Smoothed particle hydrodynamics

Daniel Valdez-Balderas, José M. Domínguez, Benedict D. Rogers, Alejandro J. C. Crespo

2013-11-01T23:59:59.000Z

222

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

Science Conference Proceedings (OSTI)

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} 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

223

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

224

Study of applied magnetic field magnetoplasmadynamic thrusters with particle-in-cell and Monte Carlo collision. II. Investigation of acceleration mechanisms  

Science Conference Proceedings (OSTI)

The particle-in-cell method previously described in paper (I) has been applied to the investigation of acceleration mechanisms in applied-field magnetoplasmadynamic thrusters. This new approach is an alternative to magnetohydrodynamics models and allows nonlocal dynamic effects of particles and improved transport properties. It was used to model a 100 kW, steady-state, applied-field, argon magnetoplasmadynamic thruster to study the physical acceleration processes with discharge currents of 1000-1500 A, mass flow rates of 0.025-0.1 g/s and applied magnetic field strengths of 0.034-0.102 T. The total thrust calculations were used to verify the theoretical approach by comparison with experimental data. Investigations of the acceleration model offer an underlying understanding of applied-field magnetoplasmadynamic thrusters, including the following conclusions: (1) swirl acceleration mechanism is the dominant contributor to the plasma acceleration, and self-magnetic, Hall, gas-dynamic, and swirl acceleration mechanisms are in an approximate ratio of 1:10:10:100; (2) the Hall acceleration produced mainly by electron swirl is insensitive to the change of externally applied magnetic field and shows only slight increases when the current is raised; (3) self-magnetic acceleration is normally negligible for all cases, while the gas-dynamic acceleration contribution increases with increasing applied magnetic field strength, discharge current, and mass flow rate.

Tang Haibin; Cheng Jiao; Liu Chang [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); York, Thomas M. [Aeronautical and Astronautical Engineering Department, Ohio State University, Columbus, Ohio 43235 (United States)

2012-07-15T23:59:59.000Z

225

User's manual for ONEDANT: a code package for one-dimensional, diffusion-accelerated, neutral-particle transport  

Science Conference Proceedings (OSTI)

ONEDANT is designed for the CDC-7600, but the program has been implemented and run on the IBM-370/190 and CRAY-I computers. ONEDANT solves the one-dimensional multigroup transport equation in plane, cylindrical, spherical, and two-angle plane geometries. Both regular and adjoint, inhomogeneous and homogeneous (k/sub eff/ and eigenvalue search) problems subject to vacuum, reflective, periodic, white, albedo, or inhomogeneous boundary flux conditions are solved. General anisotropic scattering is allowed and anisotropic inhomogeneous sources are permitted. ONEDANT numerically solves the one-dimensional, multigroup form of the neutral-particle, steady-state form of the Boltzmann transport equation. The discrete-ordinates approximation is used for treating the angular variation of the particle distribution and the diamond-difference scheme is used for phase space discretization. Negative fluxes are eliminated by a local set-to-zero-and-correct algorithm. A standard inner (within-group) iteration, outer (energy-group-dependent source) iteration technique is used. Both inner and outer iterations are accelerated using the diffusion synthetic acceleration method. (WHK)

O'Dell, R.D.; Brinkley, F.W. Jr.; Marr, D.R.

1982-02-01T23:59:59.000Z

226

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.

227

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

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Major accelerators We invite you to explore the basic plans of the world's major accelerators so...

228

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

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

Accelerators Accelerators solve two problems for physicists. First, since all particles behave like waves, physicists use accelerators to increase a particle's momentum, thus...

229

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.

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

2013-10-08T23:59:59.000Z

230

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

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

Accelerators and particle detectors - How do we experiment with tiny particles? - How to obtain particles to accelerate Electrons: Heating a metal causes electrons to be ejected. A...

231

Mass inflation in a D dimensional Reissner-Nordstrom black hole: a hierarchy of particle accelerators ?  

E-Print Network (OSTI)

We study the geometry inside the event horizon of perturbed D dimensional Reissner-Nordstrom-(A)dS type black holes showing that, similarly to the four dimensional case, mass inflation also occurs for D>4. First, using the homogeneous approximation, we show that an increase of the number of spatial dimensions contributes to a steeper variation of the metric coefficients with the areal radius and that the phenomenon is insensitive to the cosmological constant in leading order. Then, using the code reported in arXiv:0904.2669 [gr-qc] adapted to D dimensions, we perform fully non-linear numerical simulations. We perturb the black hole with a compact pulse adapting the pulse amplitude such that the relative variation of the black hole mass is the same in all dimensions, and determine how the black hole interior evolves under the perturbation. We qualitatively confirm that the phenomenon is similar to four dimensions as well as the behaviour observed in the homogeneous approximation. We speculate about the formation of black holes inside black holes triggered by mass inflation, and about possible consequences of this scenario.

P. P. Avelino; A. J. S. Hamilton; C. A. R. Herdeiro; M. Zilhao

2011-05-23T23:59:59.000Z

232

Steady-State Solutions in Nonlinear Diffusive Shock Acceleration  

E-Print Network (OSTI)

Stationary solutions to the equations of non-linear diffusive shock acceleration play a fundamental role in the theory of cosmic-ray acceleration. Their existence usually requires that a fraction of the accelerated particles be allowed to escape from the system. Because the scattering mean-free-path is thought to be an increasing function of energy, this condition is conventionally implemented as an upper cut-off in energy space -- particles are then permitted to escape from any part of the system, once their energy exceeds this limit. However, because accelerated particles are responsible for substantial amplification of the ambient magnetic field in a region upstream of the shock front, we examine an alternative approach in which particles escape over a spatial boundary. We use a simple iterative scheme that constructs stationary numerical solutions to the coupled kinetic and hydrodynamic equations. For parameters appropriate for supernova remnants, we find stationary solutions with efficient acceleration w...

Reville, B; Duffy, P

2008-01-01T23:59:59.000Z

233

Feasibility of producing a short, high energy s-band linear accelerator using a klystron power source  

SciTech Connect

Purpose: To use a finite-element method (FEM) model to study the feasibility of producing a short s-band (2.9985 GHz) waveguide capable of producing x-rays energies up to 10 MV, for applications in a linac-MR, as well as conventional radiotherapy. Methods: An existing waveguide FEM model developed by the authors' group is used to simulate replacing the magnetron power source with a klystron. Peak fields within the waveguide are compared with a published experimental threshold for electric breakdown. The RF fields in the first accelerating cavity are scaled, approximating the effect of modifications to the first coupling cavity. Electron trajectories are calculated within the RF fields, and the energy spectrum, beam current, and focal spot of the electron beam are analyzed. One electron spectrum is selected for Monte Carlo simulations and the resulting PDD compared to measurement. Results: When the first cavity fields are scaled by a factor of 0.475, the peak magnitude of the electric fields within the waveguide are calculated to be 223.1 MV/m, 29% lower than the published threshold for breakdown at this operating frequency. Maximum electron energy increased from 6.2 to 10.4 MeV, and beam current increased from 134 to 170 mA. The focal spot FWHM is decreased slightly from 0.07 to 0.05 mm, and the width of the energy spectrum increased slightly from 0.44 to 0.70 MeV. Monte Carlo results show d{sub max} is at 2.15 cm for a 10 Multiplication-Sign 10 cm{sup 2} field, compared with 2.3 cm for a Varian 10 MV linac, while the penumbral widths are 4.8 and 5.6 mm, respectively. Conclusions: The authors' simulation results show that a short, high-energy, s-band accelerator is feasible and electric breakdown is not expected to interfere with operation at these field strengths. With minor modifications to the first coupling cavity, all electron beam parameters are improved.

Baillie, Devin [Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Aubin, J. St. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Steciw, S. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

2013-04-15T23:59:59.000Z

234

Conceptual design for a linear-transformer driver (LTD)-based refurbishment and upgrade of the Saturn accelerator pulse-power system.  

Science Conference Proceedings (OSTI)

The purpose of this work was to develop a conceptual design for the Saturn accelerator using the modular Liner-Transformer Driver (LTD) technology to identify risks and to focus development and research for this new technology. We present a reference design for a Saturn class driver based on a number of linear inductive voltage adders connected in parallel. This design is very similar to a design reported five years ago [1]. However, with the design reported here we use 1-MA, 100-kV LTD cavities as building blocks. These cavities have already been built and are currently in operation at the HCEI in Tomsk, Russia [2]. Therefore, this new design integrates already-proven individual components into a full system design.

Mazarakis, Michael Gerrassimos; Struve, Kenneth William

2006-09-01T23:59:59.000Z

235

Construction of. gamma pi. /sup 0/ spectrometer and photon tagging facility at Bates Linear Accelerator. Final report, July 31, 1979-July 31, 1980  

SciTech Connect

The funds provided under Contract No. DE-AC02-79ER10486 were totally expended for hardware and supplies required by two related devices at the Bates Linear Accelerator. These were a photon tagging facility and a ..gamma pi../sup 0/ spectrometer in Beam Line C of the new South Experimental Hall. Construction was begun in November of 1979 and both systems became fully operational in the summer of 1981. Preliminary data was taken in 1980 with a prototype ..gamma pi../sup 0/ spectrometer will be carried out in the fall of 1981 and spring of 1982. The photon tagging system has been used successfully to calibrate the ..gamma pi../sup 0/ spectrometer for the BU - MIT collaboration and to test a lead glass detector system for Brandeis University.

Booth, E.C.

1981-08-01T23:59:59.000Z

236

The linear Fokker-Planck equation for the Ornstein-Uhlenbeck process as an (almost) nonlinear kinetic equation for an isolated N-particle system  

E-Print Network (OSTI)

It is long known that the Fokker-Planck equation with prescribed constant coefficients of diffusion and linear friction describes the ensemble average of the stochastic evolutions in velocity space of a Brownian test particle immersed in a heat bath of fixed temperature. Apparently, it is not so well known that the same partial differential equation, but now with constant coefficients which are functionals of the solution itself rather than being prescribed, describes the kinetic evolution (in the infinite particle limit) of an isolated N-particle system with certain stochastic interactions. Here we discuss in detail this recently discovered interpretation.

Michael Kiessling; Carlo Lancellotti

2005-03-30T23:59:59.000Z

237

Linear Correlation Between Patient Survival and Decreased Percentage of Tumor [{sup 18}F]Fluorodeoxyglucose Uptake for Late-Course Accelerated Hyperfractionated Radiotherapy for Esophageal Cancer  

SciTech Connect

Purpose: The aims of this trial were to study whether a decreased percentage of tumor fluorodeoxyglucose (FDG) uptake (%DeltaSUVmax) correlated with overall survival and local control times for patients with esophageal cancer and which patients would benefit from a late-course accelerated hyperfractionated (LCHF) radiation scheme. Methods and Materials: A total of 50 eligible patients with squamous esophageal cancer received positron-emission tomography examinations three times and were treated with the LCHF radiation scheme, with a dose of 68.4 Gy/41 fractions in 6.5 weeks. A %DeltaSUVmax value was calculated, and patients were stratified as highly radiosensitive (HR), moderately radiosensitive (MR), and low radiosensitivity (LR) according to %DeltaSUVmax values in the conventional fraction (CF) scheme. Then, a linear correlation was calculated between patients' survival time and %DeltaSUVmax. Local control and overall survival rates were compared after stratification. Results: In the MR subgroup, there was no linear correlation between %DeltaSUVmax and the CF and LCHF schemes (correlation coefficient, R < 0.4; p > 0.05). In the other subgroups (HR and LR), %DeltaSUVmax values between the CF and LCHF schemes were correlated. Also, in the HR and LR subgroups, %DeltaSUVmax after radiation correlated with overall survival or local control rates (correlation coefficient, R >0.5, and p < 0.05). Three-year local control rates in the HR, MR, and LR subgroups were 100%, 81.5%, and 0%, respectively (p < 0.001). Also, 3-year overall survival rates were 92.4%, 58.8%, and 0% for HR, MR, and LR subgroups, respectively (p < 0.001). Conclusions: Postradiation %DeltaSUVmax was positively correlated with survival time for patients' with esophageal cancer. Patients who benefited from LCHF schedules were those with a decrease of 30% to 60% in tumor FDG uptake after the completion of CF radiation.

Ma Jinbo; Song Yipeng [Department of Oncology, Shandong University School of Medicine, Shandong Province (China); Department of Radiation Oncology, Yantai Yuhuangding Hospital, School of Medicine, Qingdao University, Yantai (China); Yu Jinming, E-mail: yujmwin@yahoo.cn [Department of Oncology, Shandong University School of Medicine, Shandong Province (China); Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong Province (China); Zhou Wei [Department of Oncology, Shandong University School of Medicine, Shandong Province (China); Cheng Ercheng [Department of Radiation Oncology, Yantai Yuhuangding Hospital, School of Medicine, Qingdao University, Yantai (China); Zhang Xiqin [Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong Province (China)

2012-03-15T23:59:59.000Z

238

Human Accelerator - Teacher Overview  

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

electrons. The cavities are arranged in two long, straight sections called Linear Accelerators. In this activity, students pass tennis balls down a line like Jefferson Lab's...

239

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)

240

Research | SLAC National Accelerator Laboratory  

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

Accelerators and Society Astrophysics & Cosmology Biology Elementary Particle Physics Environmental Science Materials, Chemistry & Energy Sciences Scientific Computing X-ray...

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

[Theory of elementary particles studies in weak interaction and grand unification and studies in accelerator design]. Progress report  

Science Conference Proceedings (OSTI)

This report discusses research on: Stanford linear collider detector; Mark II; GEM; tau-charm factory; and SECC preradiator prototype and beam test. (LSP)

Not Available

1991-12-31T23:59:59.000Z

242

The Particle Adventure | Glossary  

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

Accelerator A machine used to accelerate particles to high speeds, and thus high energy compared to their rest-mass energy...

243

Hippocampal-Sparing Whole-Brain Radiotherapy: A 'How-To' Technique Using Helical Tomotherapy and Linear Accelerator-Based Intensity-Modulated Radiotherapy  

SciTech Connect

Purpose: Sparing the hippocampus during cranial irradiation poses important technical challenges with respect to contouring and treatment planning. Herein we report our preliminary experience with whole-brain radiotherapy using hippocampal sparing for patients with brain metastases. Methods and Materials: Five anonymous patients previously treated with whole-brain radiotherapy with hippocampal sparing were reviewed. The hippocampus was contoured, and hippocampal avoidance regions were created using a 5-mm volumetric expansion around the hippocampus. Helical tomotherapy and linear accelerator (LINAC)-based intensity-modulated radiotherapy (IMRT) treatment plans were generated for a prescription dose of 30 Gy in 10 fractions. Results: On average, the hippocampal avoidance volume was 3.3 cm{sup 3}, occupying 2.1% of the whole-brain planned target volume. Helical tomotherapy spared the hippocampus, with a median dose of 5.5 Gy and maximum dose of 12.8 Gy. LINAC-based IMRT spared the hippocampus, with a median dose of 7.8 Gy and maximum dose of 15.3 Gy. On a per-fraction basis, mean dose to the hippocampus (normalized to 2-Gy fractions) was reduced by 87% to 0.49 Gy{sub 2} using helical tomotherapy and by 81% to 0.73 Gy{sub 2} using LINAC-based IMRT. Target coverage and homogeneity was acceptable with both IMRT modalities, with differences largely attributed to more rapid dose fall-off with helical tomotherapy. Conclusion: Modern IMRT techniques allow for sparing of the hippocampus with acceptable target coverage and homogeneity. Based on compelling preclinical evidence, a Phase II cooperative group trial has been developed to test the postulated neurocognitive benefit.

Gondi, Vinai [Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Tolakanahalli, Ranjini [Department of Medical Physics, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Mehta, Minesh P. [Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Tewatia, Dinesh [Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Department of Medical Physics, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Rowley, Howard [Department of Neuroradiology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Kuo, John S. [Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Department of Neurological Surgery, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Khuntia, Deepak [Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Tome, Wolfgang A., E-mail: tome@humonc.wisc.ed [Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States); Department of Medical Physics, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States)

2010-11-15T23:59:59.000Z

244

Review article: A review of particle swarm optimization and its applications in Solar Photovoltaic system  

Science Conference Proceedings (OSTI)

Particle swarm optimization is a stochastic optimization, evolutionary and simulating algorithm derived from human behaviour and animal behaviour as well. Special property of particle swarm optimization is that it can be operated in continuous real number ... Keywords: Linearly decreasing inertia weight, PSO parameters & control, Particle swarm optimization, Solar Photovoltaics, Time varying acceleration coefficients

Anula Khare; Saroj Rangnekar

2013-05-01T23:59:59.000Z

245

Proposed few-optical cycle laser-driven particle accelerator structure T. Plettner, P. P. Lu, and R. L. Byer  

E-Print Network (OSTI)

. The shorter pulses enable the structure to sustain higher peak electric fields and also improve the overlap an accelerator structure geometry that is natu- rally matched for usage with such few-cycle laser pulses of the pulse envelope is seriously compromised and is considerably lower than c. Typical group-velocity values

Byer, Robert L.

246

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.

247

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

248

Proposal for the Award of Two Contracts for the Technical Services for Work on Components of CERN Particle Accelerators and High Energy Physics Experiments  

E-Print Network (OSTI)

This document concerns the award of two contracts for the technical services for work on components of CERN particle accelerators and high energy physics experiments. Following a market survey carried out among 73 firms in fourteen Member States, a call for tenders (IT-3156/SPL) was sent on 4 November 2002 to three consortia in four Member States. By the closing date, CERN had received tenders from the three consortia. The Finance Committee is invited to agree to the negotiation of two contracts with: 1) the consortium SERCO FACILITIES MANAGEMENT (NL) - GERARD PERRIER INDUSTRIE (FR) - INEO ALPES (FR), the lowest bidder, for approximately 55% of the technical services for work on components of CERN particle accelerators and high energy physics experiments, for an initial period of five years and for a total amount not exceeding 37 435 270 euros (54 902 500 Swiss francs), subject to revision for inflation from 1 January 2005. The contract will include options for two one-year extensions beyond the initial five-...

2003-01-01T23:59:59.000Z

249

Far field acceleration  

SciTech Connect

Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

Fernow, R.C.

1995-07-01T23:59:59.000Z

250

A Study of the Activated GaAs Surface for Application as an Electron Source in Particle Accelerators  

Science Conference Proceedings (OSTI)

The use of type III-V semiconductor materials as photocathodes has in recent years become a focus for the High Energy Physics community. Once activated to a negative electron affinity (NEA) state and illuminated by a laser, these materials can be used as a high-brightness source of both polarised and un-polarised electrons in some modern accelerators, for example, ALICE (Accelerators and Lasers in Combined Experiments) at Daresbury Laboratory. This paper will focus on the use of gallium arsenide (GaAs) as a photocathode, and detail the reconfiguration and re-commissioning of two vacuum systems that support standard surface science techniques such as ultraviolet/X-ray photoelectron spectroscopy (UPS/XPS), low energy electron diffraction (LEED) and auger electron spectroscopy (AES). The paper will present details of cleaning GaAs in order to maximise quantum efficiency and will provide evidence from XPS and LEED to demonstrate what is happening at the atomic level.

Chanlek, N. [University of Manchester, Manchester, M13 9PL (United Kingdom); STFC Daresbury Laboratory, Warrington, WA4 4AD (United Kingdom); Herbert, J. D.; Jones, L. B.; Middleman, K. J. [STFC Daresbury Laboratory, Warrington, WA4 4AD (United Kingdom); Jones, R. M. [University of Manchester, Manchester, M13 9PL (United Kingdom)

2009-08-04T23:59:59.000Z

251

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

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Detector shapes Physicists are curious about the events that occur during and after a particle's...

252

Klystron switching power supplies for the Internation Linear Collider  

Science Conference Proceedings (OSTI)

The International Linear Collider is a majestic High Energy Physics particle accelerator that will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. ILC will complement the Large Hadron Collider (LHC), a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, by producing electron-positron collisions at center of mass energy of about 500 GeV. In particular, the subject of this dissertation is the R&D for a solid state Marx Modulator and relative switching power supply for the International Linear Collider Main LINAC Radio Frequency stations.

Fraioli, Andrea; /Cassino U. /INFN, Pisa

2009-12-01T23:59:59.000Z

253

Compact accelerator  

DOE Patents (OSTI)

A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

Caporaso, George J. (Livermore, CA); Sampayan, Stephen E. (Manteca, CA); Kirbie, Hugh C. (Los Alamos, NM)

2007-02-06T23:59:59.000Z

254

Nuclear & Particle Physics Directorate  

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

Nuclear & Particle Physics Directorate Nuclear and Particle Physics (NPP) at BNL comprises the Collider-Accelerator Department (including the NASA Space Radiation Laboratory,...

255

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

256

Fermilab | Plan for the Future | Fermilab accelerator complex...  

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

The Fermilab accelerator complex Fermilab's accelerator complex comprises ten particle accelerators and storage rings. It produces the world's most powerful, high-energy neutrino...

257

The Particle Adventure | Glossary  

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

Synchrotron A type of circular accelerator in which the particles travel in synchronized bunches at fixed radius...

258

The Particle Adventure | Glossary  

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

Fermilab Fermi National Accelerator Laboratory in Batavia, Illinois (near Chicago). Named for particle physics pioneer Enrico Fermi...

259

The Particle Adventure | Glossary  

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

CERN CERN (European Laboratory for Particle Physics) is the major European international accelerator laboratory located near Geneva, Switzerland...

260

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);

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

A Tunable Dielectric Wakefield Accelerating Structure  

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

a (11-13) GHz dielectric accelerating structure. INTRODUCTION The field of advanced accelerators is in search of novel revolutionary technologies to allow progress in particle...

262

SLAC National Accelerator Laboratory - Scientific Programs  

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

Programs Advanced Accelerator Research Particle accelerators are complicated machines, with hundreds of thousands of components that all need to be designed, engineered and...

263

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

264

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.

265

PLASMA WAKE EXCITATION BY LASERS OR PARTICLE BEAMS  

SciTech Connect

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

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

2011-04-01T23:59:59.000Z

266

High-power accelerator technology and requirements  

SciTech Connect

Designs of high-power proton linear accelerators (linacs) for accelerator transmutation of waste (ATW) are being actively studied at Los Alamos National Laboratory and at several other laboratories worldwide. Beam parameters cover the 100- to 300-mA range in average current and 800 to 1600 MeV in energy. While ideas for such accelerators have been discussed for decades, the technology base has recently advanced to the point that the feasibility of machines in the ATW power class is now generally conceded. Factors contributing to this advance have been the following: experience gained with medium-power research accelerators, especially the LAMPF linac at Los Alamos; major improvements in the theory and technology of high-intensity high-brightness accelerators fostered by the SDIO Neutral Particle Beam program; and development of high-power continuous-wave (cw) radio-frequency (rf) generators for high-energy colliding-beam rings. The reference ATW accelerator concept described in this paper is based on room-temperature copper accelerating cavities. Advances in superconducting niobium cavity technology have opened the possibility of application to ATW-type linacs. Useful efficiency gains could be realized, especially for lower current systems, and there may be technical advantages as well. Technology issues that need to be addressed for superconducting rf linac designs include the development of high-power rf couplers, appropriate cavity designs, and superconducting focusing elements, as well as concerns about beam damage of niobium structures and dynamic rf control with high beam currents.

Lawrence, G.P. (Los Alamos National Lab., NM (United States))

1993-01-01T23:59:59.000Z

267

Advanced test accelerator: a high-current induction linac  

SciTech Connect

The Advanced Test Accelerator (ATA) is a linear induction accelerator being built at Lawrence Livermore National Laboratory. The aim of the ATA, together with its associated physics program is the research and development necessary to resolve whether particle-beam propagation is possible. Since the accelerator is the tool needed to do the basic propagation experiment, many of its design parameters are specified by the physics. The accelerator parameters are: 50 MeV, 10 kA, 70 ns pulse width (FWHM), and a 1 kHz rep-rate during a ten-pulse burst. In addition, beam quality and pulse-to-pulse repeatability must be excellent. The unique features of the accelerator are the 10 kA beam and the 1 kHz burst frequency.

Cook, E.G.; Birx, D.L.; Reginato, L.L.

1982-11-01T23:59:59.000Z

268

Design of a superconducting linear accelerator for an Infrared Free Electron Laser of the proposed Chemical Dynamics Research Laboratory at LBL  

Science Conference Proceedings (OSTI)

An accelerator complex has recently been designed at LBL as part of an Infrared Free Electron Laser facility in support of a proposed Chemical Dynamics Research Laboratory. We will outline the choice of parameters and design philosophy, which are strongly driven by the demand of reliable and spectrally stable operation of the FEL for very special scientific experiments. The design is based on a 500 MHz recirculating superconducting electron linac with highest energy reach of about 60 MeV. The accelerator is injected with beams prepared by a specially designed gun-buncher system and incorporates a near-isochronous and achromatic recirculation line tunable over a wide range of beam energies. The stability issues considered to arrive at the specific design will be outlined.

Chattopadhyay, S.; Byrns, R.; Donahue, R.; Edighoffer, J.; Gough, R.; Hoyer, E.; Kim, K.J.; Leemans, W.; Staples, J.; Taylor, B.; Xie, M.

1992-08-01T23:59:59.000Z

269

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

270

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

271

Thomas Jefferson National Accelerator Facility  

Science Conference Proceedings (OSTI)

The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, USA, is one of ten national laboratories under the aegis of the Office of Science of the U.S. Department of Energy (DOE). It is managed and operated by Jefferson Science Associates, LLC. The primary facility at Jefferson Lab is the Continuous Electron Beam Accelerator Facility (CEBAF) as shown in an aerial photograph in Figure 1. Jefferson Lab was created in 1984 as CEBAF and started operations for physics in 1995. The accelerator uses superconducting radio-frequency (srf) techniques to generate high-quality beams of electrons with high-intensity, well-controlled polarization. The technology has enabled ancillary facilities to be created. The CEBAF facility is used by an international user community of more than 1200 physicists for a program of exploration and study of nuclear, hadronic matter, the strong interaction and quantum chromodynamics. Additionally, the exceptional quality of the beams facilitates studies of the fundamental symmetries of nature, which complement those of atomic physics on the one hand and of high-energy particle physics on the other. The facility is in the midst of a project to double the energy of the facility and to enhance and expand its experimental facilities. Studies are also pursued with a Free-Electron Laser produced by an energy-recovering linear accelerator.

Joseph Grames, Douglas Higinbotham, Hugh Montgomery

2010-09-01T23:59:59.000Z

272

SLAC National Accelerator Laboratory - Roger Blandford Receives...  

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

Institute for Particle Astrophysics and Cosmology, which is jointly run by Stanford and SLAC National Accelerator Laboratory, and is a professor of particle physics and...

273

Challenges in Accelerator Beam Instrumentation  

E-Print Network (OSTI)

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

2009-01-01T23:59:59.000Z

274

Challenges in Accelerator Beam Instrumentation  

Science Conference Proceedings (OSTI)

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

275

Science at SLAC National Accelerator  

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

matter and dark energy, and develop smaller, more efficient versions of particle accelerators widely used in research, medicine and industry. As our second half-century unfolds,...

276

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.

277

High brightness electron accelerator  

DOE Patents (OSTI)

A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity.

Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

1992-12-31T23:59:59.000Z

278

Scaling of Energy Gain with Plasma Parameters in a Plasma Wakefield Accelerator  

SciTech Connect

We have recently demonstrating the doubling of the energy of particles of the ultra-short, ultra-relativistic electron bunches of the Stanford Linear Accelerator Center [1]. This energy doubling occurred in a plasma only 85 cm-long with a density of {approx} 2.6 x 10{sup 17} e{sup -}/cm{sup -3}. This milestone is the result of systematic measurements that show the scaling of the energy gain with plasma length and density, and show the reproducibility and the stability of the acceleration process. We show that the energy gain increases linearly with plasma length from 13 to 31 cm. These are key steps toward the application of beam-driven plasma accelerators or plasma wakefield accelerators (PWFA) to doubling the energy of a future linear collider without doubling its length.

Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.

2008-01-28T23:59:59.000Z

279

International linear collider reference design report  

Science Conference Proceedings (OSTI)

The International Linear Collider will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. A proposed electron-positron collider, the ILC will complement the Large Hadron Collider, a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, together unlocking some of the deepest mysteries in the universe. With LHC discoveries pointing the way, the ILC -- a true precision machine -- will provide the missing pieces of the puzzle. Consisting of two linear accelerators that face each other, the ILC will hurl some 10 billion electrons and their anti-particles, positrons, toward each other at nearly the speed of light. Superconducting accelerator cavities operating at temperatures near absolute zero give the particles more and more energy until they smash in a blazing crossfire at the centre of the machine. Stretching approximately 35 kilometres in length, the beams collide 14,000 times every second at extremely high energies -- 500 billion-electron-volts (GeV). Each spectacular collision creates an array of new particles that could answer some of the most fundamental questions of all time. The current baseline design allows for an upgrade to a 50-kilometre, 1 trillion-electron-volt (TeV) machine during the second stage of the project. This reference design provides the first detailed technical snapshot of the proposed future electron-positron collider, defining in detail the technical parameters and components that make up each section of the 31-kilometer long accelerator. The report will guide the development of the worldwide R&D program, motivate international industrial studies and serve as the basis for the final engineering design needed to make an official project proposal later this decade.

Aarons, G.

2007-06-22T23:59:59.000Z

280

Acceleration in astrophysics  

SciTech Connect

The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

Colgate, S.A.

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.


281

Steady-State Solutions in Nonlinear Diffusive Shock Acceleration  

E-Print Network (OSTI)

Stationary solutions to the equations of non-linear diffusive shock acceleration play a fundamental role in the theory of cosmic-ray acceleration. Their existence usually requires that a fraction of the accelerated particles be allowed to escape from the system. Because the scattering mean-free-path is thought to be an increasing function of energy, this condition is conventionally implemented as an upper cut-off in energy space -- particles are then permitted to escape from any part of the system, once their energy exceeds this limit. However, because accelerated particles are responsible for substantial amplification of the ambient magnetic field in a region upstream of the shock front, we examine an alternative approach in which particles escape over a spatial boundary. We use a simple iterative scheme that constructs stationary numerical solutions to the coupled kinetic and hydrodynamic equations. For parameters appropriate for supernova remnants, we find stationary solutions with efficient acceleration when the escape boundary is placed at the point where growth and advection of strongly driven non-resonant waves are in balance. We also present the energy dependence of the distribution function close to the energy where it cuts off - a diagnostic that is in principle accessible to observation.

B. Reville; J. G. Kirk; P. Duffy

2008-12-20T23:59:59.000Z

282

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

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

Accelerating particles: Animation The above is an animation of the following concept: This is a test search string for google...

283

Acceleration of polarized protons in circular accelerators  

SciTech Connect

The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

Courant, E.D.; Ruth, R.D.

1980-09-12T23:59:59.000Z

284

Proceedings of a workshop on Applications of Accelerators  

SciTech Connect

This document is a compilation of material collected as the results of a workshop, Applications of Accelerators, held at the Stanford Linear Accelerator Center, 1--2 December 1993. The material collected here has been edited for style and to minimize duplication. Footnotes will identify the original source of the material. We believe that the reader will find that this document has something for every interest. There are applications in the fields of health, food preservation, energy, environmental monitoring and protection, and industrial processing. Man y of the examples discussed have already passed the demonstration stage. Most of the others are the subject of active accelerator research. Taken as a whole, the particle accelerator field contains a wealth of application opportunities, some already in use, and many more ready to be exploited.

Herrmannsfeldt, W.B. [ed.] [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Sessler, A.M.; Alonso, J.R. [eds.] [Lawrence Berkeley Lab., CA (United States)

1994-01-31T23:59:59.000Z

285

Experiment on a Tunable Dielectric-Loaded Accelerating Structure  

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

Proceedings of IPAC'10, Kyoto, Japan THPD068 03 Linear Colliders, Lepton Accelerators and New Acceleration Techniques A14 Advanced Concepts 4437 is connected to the...

286

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

287

U.S. Department of Energy and India Partner to Advance Accelerator...  

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

India Partner to Advance Accelerator and Particle Detector Research and Development U.S. Department of Energy and India Partner to Advance Accelerator and Particle Detector...

288

Can Accelerators Accelerate Learning?  

Science Conference Proceedings (OSTI)

The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ)[1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil, Caixa Postal 68528, 21941-972 (Brazil)

2009-03-10T23:59:59.000Z

289

NERSC and CRD Help Decipher Science from Compact Accelerator...  

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

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 :...

290

Linear collider: a preview  

Science Conference Proceedings (OSTI)

Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center.

Wiedemann, H.

1981-11-01T23:59:59.000Z

291

Energy Measurement in a Plasma Wakefield Accelerator  

SciTech Connect

In the E-167 plasma wakefield acceleration experiment, electrons with an initial energy of 42GeV are accelerated in a meter-scale lithium plasma. Particles are leaving plasma with a large energy spread. To determine the spectrum of the accelerated particles, a two-plane spectrometer has been set up.

Ischebeck, R

2007-07-06T23:59:59.000Z

292

Electron acceleration during three-dimensional relaxation of an electron beam-return current plasma system in a magnetic field  

E-Print Network (OSTI)

We investigate the effects of acceleration during non-linear electron-beam relaxation in magnetized plasma in the case of electron transport in solar flares. The evolution of electron distribution functions is computed using a three-dimensional particle-in-cell electromagnetic code. Analytical estimations under simplified assumptions are made to provide comparisons. We show that, during the non-linear evolution of the beam-plasma system, the accelerated electron population appears. We found that, although the electron beam loses its energy efficiently to the thermal plasma, a noticeable part of the electron population is accelerated. For model cases with initially monoenergetic beams in uniform plasma, we found that the amount of energy in the accelerated electrons above the injected beam-electron energy varies depending the plasma conditions and could be around 10-30% of the initial beam energy. This type of acceleration could be important for the interpretation of non-thermal electron populations in solar f...

Karlicky, M

2012-01-01T23:59:59.000Z

293

Subcritical Fission Reactor Based on Linear  

E-Print Network (OSTI)

The beams of Linear Collider after main collision can be utilized to build an accelerator–driven sub–critical reactor. ? The project of Linear Collider (LC) contains one essential element that is not present in other colliders. Here each electron (or positron or photon) bunch will be used only once, and physical collision leave two very dense and strongly collimated beams of high energy electrons or/and photons with precisely known time structure. We consider, for definiteness, electron beam parameters of the TESLA project [1] particle energy Ee = 250 GeV, number of electrons per second Ne = 2.7 · 10 14 /s, mean beam power Pb ? 11 MWt, transverse size and angular spread negligible. (1) In the Photon Collider mode the used beams contain photons, electrons and

I. F. Ginzburg

2005-01-01T23:59:59.000Z

294

Research Accelerator Division | Neutron Science | ORNL  

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

Kevin Jones The Research Accelerator Division is responsible for operation of the SNS accelerator complex, which consists of a negative hydrogen-ion injector, a 1 GeV linear...

295

Research Accelerator Division | ORNL Neutron Sciences  

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

Kevin Jones. The Research Accelerator Division (RAD) is responsible for operation of the SNS accelerator complex, which consists of a negative hydrogen-ion injector, a 1 GeV linear...

296

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

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Fixed target experiments In a fixed-target experiment, a charged particle such as an electron or a...

297

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

298

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

299

Acceleration Mechanisms  

E-Print Network (OSTI)

Glossary I. Background and context of the subject II. Stochastic acceleration III. Resonant scattering IV. Diffusive shock acceleration V. DSA at multiple shocks VI. Applications of DSA VII. Acceleration by parallel electric fields VIII. Other acceleration mechanisms IX. Future directions X. Appendix: Quasilinear equations XI. Bibliography

Melrose, D B

2009-01-01T23:59:59.000Z

300

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.

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

Panel discussion on laboratory accelerator programs: present and future  

SciTech Connect

The present SLAC accelerator program is summarized briefly, and the future of electron-positron colliders is discussed. Present activities discussed include the PEP storage ring, the SPEAR storage ring, the Linear Accelerator, and the SLAC Linear Collider (SLC) project. Future prospects include a larger scale linear collider. The stability requirements on acceleration are briefly discussed. (LEW)

Richter, B.

1986-09-01T23:59:59.000Z

302

ACCELERATED LINEARIZED BREGMAN METHOD June 21, 2011 ...  

E-Print Network (OSTI)

Jun 21, 2011... 10-16571, ONR. Grants N00014-03-0514 and N00014-08-1-1118, and DOE Grants DE-FG01-92ER-25126 and DE-FG02-08ER-25856. 1 ...

303

SLAC National Accelerator Laboratory - Fermi-LAT Designer Awarded...  

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

said. Now with the Santa Cruz Institute for Particle Physics, Atwood was a long-time SLAC National Accelerator Laboratory particle physicist who maintains his lab ties through...

304

Muon Acceleration - RLA and FFAG  

SciTech Connect

Various acceleration schemes for muons are presented. The overall goal of the acceleration systems: large acceptance acceleration to 25 GeV and 'beam shaping' can be accomplished by various fixed field accelerators at different stages. They involve three superconducting linacs: a single pass linear Pre-accelerator followed by a pair of multi-pass Recirculating Linear Accelerators (RLA) and finally a non-scaling FFAG ring. The present baseline acceleration scenario has been optimized to take maximum advantage of appropriate acceleration scheme at a given stage. The solenoid based Pre-accelerator offers very large acceptance and facilitates correction of energy gain across the bunch and significant longitudinal compression trough induced synchrotron motion. However, far off-crest acceleration reduces the effective acceleration gradient and adds complexity through the requirement of individual RF phase control for each cavity. The RLAs offer very efficient usage of high gradient superconducting RF and ability to adjust path-length after each linac pass through individual return arcs with uniformly periodic FODO optics suitable for chromatic compensation of emittance dilution with sextupoles. However, they require spreaders/recombiners switchyards at both linac ends and significant total length of the arcs. The non-scaling Fixed Field Alternating Gradient (FFAG) ring combines compactness with very large chromatic acceptance (twice the injection energy) and it allows for large number of passes through the RF (at least eight, possibly as high as 15).

Alex Bogacz

2011-10-01T23:59:59.000Z

305

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

306

Evaluation of a 45° Slant Quasi-Linear Radar Polarization State for Distinguishing Drizzle Droplets, Pristine Ice Crystals, and Less Regular Ice Particles  

Science Conference Proceedings (OSTI)

A remote sensing capability is needed to detect clouds of supercooled, drizzle-sized droplets, which are a major aircraft icing hazard. Discrimination among clouds of differing ice particle types is also important because both the presence and ...

Roger F. Reinking; Sergey Y. Matrosov; Robert A. Kropfli; Bruce W. Bartram

2002-03-01T23:59:59.000Z

307

Accelerations in Steep Gravity Waves. II: Subsurface Accelerations  

Science Conference Proceedings (OSTI)

It is shown that the vertical acceleration of a particle beneath the crest of a step gravity wave does not always decrease monotonically with depth in the fluid. When the wave steepness ak exceeds 0.4, the acceleration at first increases with ...

M. S. Longuet-Higgins

1986-07-01T23:59:59.000Z

308

SLAC National Accelerator Laboratory - Facility for Advanced...  

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

2012 as a test bed for technologies that will power the next generation of particle accelerators. It also hosts experiments that require extreme electric and magnetic fields. Visit...

309

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

310

Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude  

DOE Patents (OSTI)

A beam current limiter 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.

Bogaty, John M. (Lombard, IL); Clifft, Benny E. (Park Forest, IL); Bollinger, Lowell M. (Downers Grove, IL)

1995-01-01T23:59:59.000Z

311

IMPACT-T: Accelerator Physics  

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

IMPACTT General Description IMPACT-T (Integrated Map and Particle Accelerator Tracking-Time) is a parallel, three-dimensional, quasi-static beam dynamics code used to study...

312

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.

313

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

314

Acceleration of colliding shells around a black hole: Validity of the test particle approximation in the Banados-Silk-West process  

SciTech Connect

Recently, Banados, Silk and West (BSW) showed that the total energy of two colliding test particles has no upper limit in their center of mass frame in the neighborhood of an extreme Kerr black hole, even if these particles were at rest at infinity in the infinite past. We call this mechanism the BSW mechanism or BSW process. The large energy of such particles would generate strong gravity, although this has not been taken into account in the BSW analysis. A similar mechanism is seen in the collision of two spherical test shells in the neighborhood of an extreme Reissner-Nordstroem black hole. In this paper, in order to draw some implications concerning the effects of gravity generated by colliding particles in the BSW process, we study a collision of two spherical dust shells, since their gravity can be exactly treated. We show that the energy of two colliding shells in the center of mass frame observable from infinity has an upper limit due to their own gravity. Our result suggests that an upper limit also exists for the total energy of colliding particles in the center of mass frame in the observable domain in the BSW process due the gravity of the particles.

Kimura, Masashi; Nakao, Ken-ichi [Department of Mathematics and Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan); Tagoshi, Hideyuki [Department of Earth and Space Science, Graduate School of Science, Osaka University, Osaka 560-0043 (Japan)

2011-02-15T23:59:59.000Z

315

Frequency scaling of linear super-colliders  

SciTech Connect

The development of electron-positron linear colliders in the TeV energy range will be facilitated by the development of high-power rf sources at frequencies above 2856 MHz. Present S-band technology, represented by the SLC, would require a length in excess of 50 km per linac to accelerate particles to energies above 1 TeV. By raising the rf driving frequency, the rf breakdown limit is increased, thereby allowing the length of the accelerators to be reduced. Currently available rf power sources set the realizable gradient limit in an rf linac at frequencies above S-band. This paper presents a model for the frequency scaling of linear colliders, with luminosity scaled in proportion to the square of the center-of-mass energy. Since wakefield effects are the dominant deleterious effect, a separate single-bunch simulation model is described which calculates the evolution of the beam bunch with specified wakefields, including the effects of using programmed phase positioning and Landau damping. The results presented here have been obtained for a SLAC structure, scaled in proportion to wavelength.

Mondelli, A.; Chernin, D.; Drobot, A.; Reiser, M.; Granatstein, V.

1986-06-01T23:59:59.000Z

316

Two-Pulse Ionization Injection into Quasi-Linear Laser Wakefields  

E-Print Network (OSTI)

We describe a scheme for controlling electron injection into the quasi-linear wakefield driven by a guided drive pulse via ionization of a dopant species by a collinear injection laser pulse with a short Rayleigh range. The scheme is analyzed by particle in cell simulations which show controlled injection and acceleration of electrons to an energy of 370 MeV, a relative energy spread of 2%, and a normalized transverse emittance of 3.0 {\\mu}m.

Bourgeois, Nicolas; Hooker, Simon M

2013-01-01T23:59:59.000Z

317

Visualizing Particle-in-Cell Simulation of Laser Wakefield Particle...  

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

and assist in the planning of the next generation of particle accelerators and ultrafast applications in chemistry and biology. This image shows a horizontal slice through...

318

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.

319

High intensity hadron accelerators  

SciTech Connect

This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics.

Teng, L.C.

1989-05-01T23:59:59.000Z

320

Comoving acceleration of overdense electron-positron plasma by colliding ultra-intense laser pulses  

Science Conference Proceedings (OSTI)

Particle-in-cell (PIC) simulation results of sustained acceleration of electron-positron (e+e-) plasmas by comoving electromagnetic (EM) pulses are presented. When a thin slab of overdense e+e- plasma is irradiated with linear-polarized ultra-intense short laser pulses from both sides, the pulses are transmitted when the plasma is compressed to thinner than {approx}2 relativistic skin depths. A fraction of the plasma is then captured and efficiently accelerated by self-induced JxB forces. For 1 {mu}m laser and 10{sup 21} W cm{sup -2} intensity, the maximum energy exceeds GeV in a picosecond.

Liang, Edison [Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

2006-06-15T23:59:59.000Z

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
to obtain the most current and comprehensive results.


321

Linear Collider Physics Resource Book Snowmass 2001  

Science Conference Proceedings (OSTI)

The American particle physics community can look forward to a well-conceived and vital program of experimentation for the next ten years, using both colliders and fixed target beams to study a wide variety of pressing questions. Beyond 2010, these programs will be reaching the end of their expected lives. The CERN LHC will provide an experimental program of the first importance. But beyond the LHC, the American community needs a coherent plan. The Snowmass 2001 Workshop and the deliberations of the HEPAP subpanel offer a rare opportunity to engage the full community in planning our future for the next decade or more. A major accelerator project requires a decade from the beginning of an engineering design to the receipt of the first data. So it is now time to decide whether to begin a new accelerator project that will operate in the years soon after 2010. We believe that the world high-energy physics community needs such a project. With the great promise of discovery in physics at the next energy scale, and with the opportunity for the uncovering of profound insights, we cannot allow our field to contract to a single experimental program at a single laboratory in the world. We believe that an e{sup +}e{sup -} linear collider is an excellent choice for the next major project in high-energy physics. Applying experimental techniques very different from those used at hadron colliders, an e{sup +}e{sup -} linear collider will allow us to build on the discoveries made at the Tevatron and the LHC, and to add a level of precision and clarity that will be necessary to understand the physics of the next energy scale. It is not necessary to anticipate specific results from the hadron collider programs to argue for constructing an e{sup +}e{sup -} linear collider; in any scenario that is now discussed, physics will benefit from the new information that e{sup +}e{sup -} experiments can provide. This last point merits further emphasis. If a new accelerator could be designed and built in a few years, it would make sense to wait for the results of each accelerator before planning the next one. Thus, we would wait for the results from the Tevatron before planning the LHC experiments, and wait for the LHC before planning any later stage. In reality accelerators require a long time to construct, and they require such specialized resources and human talent that delay can cripple what would be promising opportunities. In any event, we believe that the case for the linear collider is so compelling and robust that we can justify this facility on the basis of our current knowledge, even before the Tevatron and LHC experiments are done. The physics prospects for the linear collider have been studied intensively for more than a decade, and arguments for the importance of its experimental program have been developed from many different points of view. This book provides an introduction and a guide to this literature. We hope that it will allow physicists new to the consideration of linear collider physics to start from their own personal perspectives and develop their own assessments of the opportunities afforded by a linear collider.

Ronan (Editor), M.T.

2001-06-01T23:59:59.000Z

322

Log-parabolic spectra and particle acceleration in blazars. III: SSC emission in the TeV band from Mkn 501  

E-Print Network (OSTI)

Curved broad-band spectral distributions of non-thermal sources like blazars are described well by a log-parabolic (LP) law where the second degree term measures the curvature. LP energy spectra can be obtained for relativistic electrons by means of a statistical acceleration mechanism whose probability of acceleration depends on energy. In this paper we compute the spectra radiated by an electron population via synchrotron (S) and Synchro-Self Compton(SSC) processes to derive the relations between the LP parameters. These spectra were obtained by means of an accurate numerical code. We found that the ratio between the curvature parameters of the S spectrum to that of the electrons is equal to about 0.2 instead of 0.25, the value foreseen in the delta approximation. Inverse Compton spectra are also intrinsically curved and can be approximated by a log-parabola only in limited ranges. The curvature parameter, estimated around the SED peak, may vary from a lower value than that of the S spectrum up to that of emitting electrons depending on whether the scattering is in the Thomson or in the Klein-Nishina regime. We applied this analysis to computing the SSC emission from the BL Lac object Mkn 501 during the large flare of April 1997. We fit simultaneous BeppoSAX and CAT data and reproduced intensities and spectral curvatures of both components with good accuracy. The large curvature observed in the TeV range was found to be mainly intrinsic, and therefore did not require a large pair production absorption against the extragalactic background. We regard this finding as an indication that the Universe is more transparent at these energies than previously assumed by several models found in the literature. This conclusion is supported by recent detection of two relatively high redshift blazars with H.E.S.S.

E. Massaro; A. Tramacere; M. Perri; P. Giommi; G. Tosti

2005-11-23T23:59:59.000Z

323

The Particle Adventure | Glossary  

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

Collider A collider is an accelerator in which two beams traveling in opposite directions are steered together to provide high-energy collisions between the particles in one beam...

324

The Particle Adventure | Glossary  

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

Fixed-target Experiment An experiment in which the beam of particles from an accelerator is directed at a stationary (or nearly stationary) target. The target may be a solid, a...

325

SLAC National Accelerator Laboratory - Accelerator Directorate  

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

physics. Today, the Accelerator Directorate operates and maintains SLAC's existing accelerators to provide the highest possible level of performance. Accelerator employees improve...

326

Muon Acceleration in Cosmic-ray Sources  

E-Print Network (OSTI)

Many models of ultra-high energy cosmic-ray production involve acceleration in linear accelerators located in Gamma-Ray Bursts magnetars, or other sources. These source models require very high accelerating gradients, $10^{13}$ keV/cm, with the minimum gradient set by the length of the source. At gradients above 1.6 keV/cm, muons produced by hadronic interactions undergo significant acceleration before they decay. This acceleration hardens the neutrino energy spectrum and greatly increases the high-energy neutrino flux. We rule out many models of linear acceleration, setting strong constraints on plasma wakefield accelerators and on models for sources like Gamma Ray Bursts and magnetars.

Spencer R. Klein; Rune Mikkelsen; Julia K. Becker Tjus

2012-08-09T23:59:59.000Z

327

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

328

Open Problems in $?$ Particle Condensation  

E-Print Network (OSTI)

$\\alpha$ particle condensation is a novel state in nuclear systems. We briefly review the present status on the study of $\\alpha$ particle condensation and address the open problems in this research field: $\\alpha$ particle condensation in heavier systems other than the Hoyle state, linear chain and $\\alpha$ particle rings, Hoyle-analogue states with extra neutrons, $\\alpha$ particle condensation related to astrophysics, etc.

Y. Funaki; M. Girod; H. Horiuchi; G. Roepke; P. Schuck; A. Tohsaki; T. Yamada

2010-03-05T23:59:59.000Z

329

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.

330

High-Energy Laser Ponderomotive Acceleration  

SciTech Connect

A new concept of TeV-range laser ponderomotive acceleration in a plasma is proposed. Particles are accelerated in the point-like scattering by the leading front of the laser pulse, propagating at the group velocity less than the vacuum speed of light. In this scheme, the gain in particle energy is determined by the group velocity and does not depend on laser intensity, which determines the quantum probability of acceleration. The quantum and classical analysis of the scheme proposed is presented. Estimates show that the concept proposed is a promising technique for compact laser acceleration of TeV energy range.

Smetanin, I.V.; /Lebedev Inst.; Barnes, C.; /SLAC; Nakajima, K.; /KEK, Tsukuba

2006-03-10T23:59:59.000Z

331

Log-parabolic spectra and particle acceleration in blazars - II: The BeppoSAX wide band X-ray spectra of Mkn 501  

E-Print Network (OSTI)

We present the results of a spectral and temporal study of the complete set of BeppoSAX NFI (11) and WFC (71) observations of the BL Lac object Mkn 501. The WFC 2-28 keV data, reported here for the first time, were collected over a period of about five years, from September 1996 to October 2001. These observations, although not evenly distributed, show that Mkn 501, after going through a very active phase from spring 1997 to early 1999, remained in a low brightness state until late 2001. The data from the LECS, MECS and PDS instruments, covering the wide energy interval 0.1-150 keV, have been used to study in detail the spectral variability of the source. We show that the X-ray energy distribution of Mkn 501 is well described by a log-parabolic law in all luminosity states. This model allowed us to obtain good estimates of the SED synchrotron peak energy and of its associated power. The strong spectral variability observed, consisting of strictly correlated changes between the synchrotron peak energy and bolometric flux, suggests that the main physical changes are not only due to variations of the maximum Lorentz factor of the emitting particles but that other quantities must be varying as well. During the 1997 flare the high energy part of the spectrum of Mkn 501 shows evidence of an excess above the best fit log-parabolic law suggesting the existence of a second emission component that may be responsible for most of the observed variability.

E. Massaro; M. Perri; P. Giommi; R. Nesci; F. Verrecchia

2004-05-07T23:59:59.000Z

332

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

333

Searching for Cosmic Accelerators via IceCube  

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

universe there are particle accelerators 40 million times more powerful than the Large Hadron Collider (LHC) at CERN. Scientists don't know what these cosmic accelerators are or...

334

SLAC National Accelerator Laboratory - Shaken, Not Heated: the...  

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

Working at the SLAC National Accelerator Laboratory's Linear Coherent Light Source (LCLS), the scientists aimed intense, 130-femtosecond-long pulses of terahertz light at...

335

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

336

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

337

The Particle Adventure | How do we interpret our data? | Measuring...  

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

Accelerators and particle detectors - How do we interpret our data? - Measuring charge and momentum One important function of the detector is to measure a particle's charge and...

338

Accelerator Technology Division progress report, FY 1992  

SciTech Connect

This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

1993-07-01T23:59:59.000Z

339

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.

Schlyer, David J. (Bellport, NY); Ferrieri, Richard A. (Patchogue, NY); Koehler, Conrad (Miller Place, NY)

1999-01-01T23:59:59.000Z

340

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

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

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

342

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

343

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

SciTech Connect

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

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

2000-06-01T23:59:59.000Z

344

SLAC National Accelerator Laboratory - LCLS-II Project Director...  

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

winner of the Robert R. Wilson Prize for Achievement in the Physics of Particle Accelerators, awarded by the American Physical Society. The prize, which honors and encourages...

345

SLAC National Accelerator Laboratory - Turning Data Into Wild...  

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

researchers at KIPAC, the Kavli Institute for Particle Astrophysics andCosmology, at SLAC National Accelerator Laboratory and StanfordUniversity. Rather than relying purely...

346

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

347

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

348

Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator  

Science Conference Proceedings (OSTI)

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

349

MUON ACCELERATION  

Science Conference Proceedings (OSTI)

One of the major motivations driving recent interest in FFAGs is their use for the cost-effective acceleration of muons. This paper summarizes the progress in this area that was achieved leading up to and at the FFAG workshop at KEK from July 7-12, 2003. Much of the relevant background and references are also given here, to give a context to the progress we have made.

BERG,S.J.

2003-11-18T23:59:59.000Z

350

Electron acceleration in solar noise storms  

E-Print Network (OSTI)

We present an up-to-date review of the physics of electron acceleration in solar noi se storms. We describe the observed characteristics of noise storm emission, emphasi zing recent advances in imaging observations. We briefly describe the general method ology of treating particle acceleration problems and apply it to the specific proble m of electron acceleration in noise storms. We dwell on the issue of the efficiency of the overall noise storm emission process and outline open problems in this area.

Subramanian, P

2007-01-01T23:59:59.000Z

351

Electron acceleration in solar noise storms  

E-Print Network (OSTI)

We present an up-to-date review of the physics of electron acceleration in solar noi se storms. We describe the observed characteristics of noise storm emission, emphasi zing recent advances in imaging observations. We briefly describe the general method ology of treating particle acceleration problems and apply it to the specific proble m of electron acceleration in noise storms. We dwell on the issue of the efficiency of the overall noise storm emission process and outline open problems in this area.

Prasad Subramanian

2007-01-23T23:59:59.000Z

352

The Hamiltonian Mechanics of Stochastic Acceleration  

SciTech Connect

We show how to nd the physical Langevin equation describing the trajectories of particles un- dergoing collisionless stochastic acceleration. These stochastic di erential equations retain not only one-, but two-particle statistics, and inherit the Hamiltonian nature of the underlying microscopic equations. This opens the door to using stochastic variational integrators to perform simulations of stochastic interactions such as Fermi acceleration. We illustrate the theory by applying it to two example problems.

Burby, J. W.

2013-07-17T23:59:59.000Z

353

What is an accelerator?  

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

world of physics though, 'accelerator' means something a little more specific. Our accelerators are a whole class of machines that accelerate atoms, or more often, pieces of...

354

Argonne Accelerator Institute  

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

Argonne Accelerator Institute: Mission The mission of the Argonne Accelerator Institute is centered upon the following related goals: Locate next generation accelerator facilities...

355

SLAC National Accelerator Laboratory - Accelerator Research  

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

An image of the FACET equipment and a man examining it. ACCELERATOR PHYSICS Accelerators form the backbone of SLAC's on-site experimental program. They are complicated...

356

Slow Wave Structures for Charged Particle Applications  

of light in free space. This slower wave speed is important for acceleration of charged particles. The special shape of the cross-

357

Does an accelerated electron radiate Unruh radiation?  

E-Print Network (OSTI)

An accelerated particle sees the Minkowski vacuum as thermally excited, and the particle moves stochastically due to an interaction with the thermal bath. This interaction fluctuates the particle's transverse momenta like the Brownian motion in a heat bath. Because of this fluctuating motion, it has been discussed that the accelerated charged particle emits extra radiation (the Unruh radiation) in addition to the classical Larmor radiation, and experiments are under planning to detect such radiation by using ultrahigh intensity lasers constructed in near future. There are, however, counterarguments that the radiation is canceled by an interference effect between the vacuum fluctuation and the fluctuating motion. In fact, in the case of an internal detector where the Heisenberg equation of motion can be solved exactly, there is no additional radiation after the thermalization is completed. In this paper, we revisit the issue in the case of an accelerated charged particle in the scalar QED. We first prove the e...

Iso, Satoshi; Zhang, Sen

2010-01-01T23:59:59.000Z

358

Accelerators and the Accelerator Community  

Science Conference Proceedings (OSTI)

In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

Malamud, Ernest; Sessler, Andrew

2008-06-01T23:59:59.000Z

359

SLAC National Accelerator Laboratory - Elementary Particle Physics  

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

experiment and is contributing to the ATLAS science program. SLAC is also involved in R&D for future upgrades to components of the ATLAS detector. ATLAS and the LHC are...

360

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.

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

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

362

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

363

Particle energization in 3D magnetic reconnection of relativistic pair plasmas  

Science Conference Proceedings (OSTI)

We present large scale 3D particle-in-cell simulations to examine particle energization in magnetic reconnection of relativistic electron-positron (pair) plasmas. The initial configuration is set up as a relativistic Harris equilibrium without a guide field. These simulations are large enough to accommodate a sufficient number of tearing and kink modes. Contrary to the non-relativistic limit, the linear tearing instability is faster than the linear kink instability, at least in our specific parameters. We find that the magnetic energy dissipation is first facilitated by the tearing instability and followed by the secondary kink instability. Particles are mostly energized inside the magnetic islands during the tearing stage due to the spatially varying electric fields produced by the outflows from reconnection. Secondary kink instability leads to additional particle acceleration. Accelerated particles are, however, observed to be thermalized quickly. The large amplitude of the vertical magnetic field resulting from the tearing modes by the secondary kink modes further help thermalizing the non-thermal particles generated from the secondary kink instability. Implications of these results for astrophysics are briefly discussed.

Liu Wei; Yin Lin; Albright, B. J.; Bowers, K. J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Liang, Edison P. [Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States); Li Hui

2011-05-15T23:59:59.000Z

364

SuperB Progress Report for Accelerator  

Science Conference Proceedings (OSTI)

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

365

Proposed research on advanced accelerator concepts  

Science Conference Proceedings (OSTI)

This report summarizes technical progress and accomplishments during the proposed three-year research on advanced accelerator concepts supported by the Department of Energy under Contract No. DE-FG02-88ER40465. A vigorous theoretical program has been pursued in critical problem areas related to advanced accelerator concepts and the basic equilibrium, stability, and radiation properties of intense charged particle beams. Broadly speaking, our research has made significant contributions in the following three major areas: Investigations of physics issues related to particle acceleration including two-beam accelerators and cyclotron resonance laser (CRL) accelerators; Investigations of RF sources including the free- electron lasers, cyclotron resonance masers, and relativistic magnetrons; Studies of coherent structures in electron plasmas and beams ranging from a low-density, nonrelativistic, pure electron plasma column to high-density, relativistic, non-neutral electron flow in a high-voltage diode. The remainder of this report presents theoretical and computational advances in these areas.

Davidson, R.C.; Wurtele, J.S.

1991-09-01T23:59:59.000Z

366

Linear electric field mass spectrometry  

DOE Patents (OSTI)

A mass spectrometer is described having a low weight and low power requirement, for use in space. It can be used to analyze the ionized particles in the region of the spacecraft on which it is mounted. High mass resolution measurements are made by timing ions moving through a gridless cylindrically sysmetric linear electric field.

McComas, D.J.; Nordholt, J.E.

1991-03-29T23:59:59.000Z

367

Commnity 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 is 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 SciDAC1 Accelerator Science and Technology project, the SciDAC2 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 modeling. 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 multi-physics 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.

Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne; Mori, Warren; /UCLA; Ng, Cho; /SLAC; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

2008-07-01T23:59:59.000Z

368

Commnity 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.

Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne; Mori, Warren; /UCLA; Ng, Cho; /SLAC; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

2011-10-21T23:59:59.000Z

369

Surfatron laser-plasma accelerator: prospects and limitations  

SciTech Connect

The surfatron laser-plasma accelerator is an extension of the plasma beat wave accelerator scheme. It utilizes very intense electric fields, 10/sup 9/ to 10/sup 10/ V/cm, associated with focussed laser beams to accelerate particles. (GHT)

Joshi, C.

1983-01-01T23:59:59.000Z

370

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

371

Linear Quadratic  

E-Print Network (OSTI)

The proposal of Reshef et. al. (“MIC”) is an interesting new approach for discovering non-linear dependencies among pairs of measurements in exploratory data mining. However, it has a potentially serious drawback. The authors laud the fact that MIC has no preference for some alternatives over others, but as the authors know, there is no free lunch in Statistics: tests which strive to have high power against all alternatives can have low power in many important situations. To investigate this, we ran simulations to compare the power of MIC to that of standard Pearson correlation and distance correlation (dcor) Székely & Rizzo (2009). We simulated pairs of variables with different relationships (most of which were considered by the Reshef et. al.), but with varying levels of noise added. To determine proper cutoffs for testing the independence hypothesis, we simulated independent data with the appropriate marginals. As one can see from the Figure, MIC has lower power than dcor, in every case except the somewhat pathological

Noah Simon; Robert Tibshirani; Noah Simon; Robert Tibshirani

2011-01-01T23:59:59.000Z

372

Exact analysis of particle dynamics in combined field of finite duration laser pulse and static axial magnetic field  

Science Conference Proceedings (OSTI)

Dynamics of a charged particle is studied in the field of a relativistically intense linearly polarized finite duration laser pulse in the presence of a static axial magnetic field. For a finite duration laser pulse whose temporal shape is defined by Gaussian profile, exact analytical expressions are derived for the particle trajectory, momentum, and energy as function of laser phase. From the solutions, it is shown that, unlike for the monochromatic plane wave case, resonant phase locking time between the particle and laser pulse is finite. The net energy transferred to the particle does not increase monotonically but tends to saturate. It is further shown that appropriate tuning of cyclotron frequency of the particle with the characteristic frequency in the pulse spectrum can lead to the generation of accelerated particles with variable energies in MeV-TeV range.

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

2012-11-15T23:59:59.000Z

373

EFFICIENT PARALLEL COMPUTATION OF ALL-PAIRS N-BODY ACCELERATION BY DO-LOOP FOLDING  

SciTech Connect

The computational load inside a do loop is equalized by folding the loop appropriately if the amount of load is a linear function of the loop index. Using this idea, we develop an efficient parallel computation scheme of Newtonian all-pairs N-body acceleration vectors with help from OpenMP architecture. Using a consumer PC with a quad-core eight-thread processor, the new parallel scheme runs 4.2-4.9 times faster than a serial computation when the number of particles exceeds a few hundred.

Fukushima, Toshio, E-mail: Toshio.Fukushima@nao.ac.jp [National Astronomical Observatory, Ohsawa, Mitaka, Tokyo 181-8588 (Japan)

2011-07-15T23:59:59.000Z

374

Direct High-Power Laser Acceleration of Ions for Medical Applications  

Science Conference Proceedings (OSTI)

Theoretical investigations show that linearly and radially polarized multiterawatt and petawatt laser beams, focused to subwavelength waist radii, can directly accelerate protons and carbon nuclei, over micron-size distances, to the energies required for hadron cancer therapy. Ions accelerated by radially polarized lasers have generally a more favorable energy spread than those accelerated by linearly polarized lasers of the same intensity.

Salamin, Yousef I. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Physics Department, American University of Sharjah, POB 26666, Sharjah (United Arab Emirates); Harman, Zoltan; Keitel, Christoph H. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

2008-04-18T23:59:59.000Z

375

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

376

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

377

Accelerator and electrodynamics capability review  

Science Conference Proceedings (OSTI)

Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

Jones, Kevin W [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

378

Science Accelerator Widget  

Office of Scientific and Technical Information (OSTI)

Science Accelerator Widget You can now explore multiple Science Accelerator features through the new tabbed widget. Download this tool via the 'Get Widget Options' link or by...

379

Argonne Accelerator Institute  

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

Accelerators at Argonne Argonne has a long and continuing history of participation in accelerator based, and user oriented facilities. The Zero-Gradient Synchrotron, which began...

380

Review of Particle Physics  

SciTech Connect

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, V{sub ud} and V{sub us}, V{sub cb} and V{sub ub}, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.

Particle Data Group; Nakamura, Kenzo; al., et

2010-06-30T23:59:59.000Z

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.


381

Acceleration of laser-driven ion bunch from double-layer thin foils  

SciTech Connect

Generation of monoenergetic ion bunch from a double-layer thin-foil target irradiated by an intense linearly polarized laser pulse is investigated using two-dimensional particle-in-cell simulation. The protons in the front low-density hydrogen target layer accelerated by the space-charge field of the laser-driven hot electrons can penetrate through the high-Z high-mass and high-density ion layer, resulting in an energetic proton bunch. A part of the latter is further accelerated by the space-charge field of the hot electrons in the vacuum behind the high-Z ion layer. With this scheme, quasi-monoenergetic proton bunches can be produced using presently available laser pulses of moderate contrast and duration.

Wang, X.; Liang, E. [Rice University, Houston, Texas 77005-1892 (United States); Yu, W. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

2012-05-15T23:59:59.000Z

382

The Particle Adventure | How do we know any of this? | How physicists...  

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

Accelerators and particle detectors - How do we know any of this? - How physicists experiment Rutherford's experiment set the tone for the realm of experimentation in particle...

383

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

384

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.

385

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,

386

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.

387

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

388

NIST MIRF - Accelerator Radiation Physics  

Science Conference Proceedings (OSTI)

Accelerator Radiation Physics. Medium-energy accelerators are under investigation for production of channeling radiation ...

389

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

390

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

391

Design considerations for a laser-plasma linear collider  

SciTech Connect

Design considerations for a next-generation electron-positron linear collider based on laser-plasma-accelerators are discussed. Several of the advantages and challenges of laser-plasma based accelerator technology are addressed. An example of the parameters for a 1 TeV laser-plasma based collider is presented.

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

2008-08-01T23:59:59.000Z

392

SLAC National Accelerator Laboratory - SLAC National Accelerator...  

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

Security Notice and Terms of Use Updated January 3, 2005 PRIVACY NOTICE Welcome to the SLAC National Accelerator Laboratory website. We collect no personal information about you...

393

Proceedings of the first international workshop on accelerator alignment  

Science Conference Proceedings (OSTI)

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

394

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

395

Linear Thermite Charge  

The Linear Thermite Charge (LTC) is designed to rapidly cut through concrete and steel structural components by using extremely high temperature thermite reactions jetted through a linear nozzle. 

396

Fluid preconditioning for Newton-Krylov-based, fully implicit, electrostatic particle-in-cell simulations  

E-Print Network (OSTI)

A recent proof-of-principle study proposes an energy- and charge-conserving, nonlinearly implicit electrostatic particle-in-cell (PIC) algorithm in one dimension [Chen et al, J. Comput. Phys., 230 (2011) 7018]. The algorithm in the reference employs an unpreconditioned Jacobian-free Newton-Krylov method, which ensures nonlinear convergence at every timestep (resolving the dynamical timescale of interest). Kinetic enslavement, which is one key component of the algorithm, not only enables fully implicit PIC a practical approach, but also allows preconditioning the kinetic solver with a fluid approximation. This study proposes such a preconditioner, in which the linearized moment equations are closed with moments computed from particles. Effective acceleration of the linear GMRES solve is demonstrated, on both uniform and non-uniform meshes. The algorithm performance is largely insensitive to the electron-ion mass ratio. Numerical experiments are performed on a 1D multi-scale ion acoustic wave test problem.

Chen, Guangye; Leibs, Christopher A; Knoll, Dana A; Taitano, William

2013-01-01T23:59:59.000Z

397

STANFORD LINEAR ACCELERATOR CENTER Winter 1999, Vol. 29, No. 3  

E-Print Network (OSTI)

Energy. It has been my pleasure to collaborate with Hans D. Gouger, Kevan D. Weaver and J. Steven Herring

California at Santa Cruz, University of

398

2010 Annual Planning Summary for Stanford Linear Accelerator...  

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

Annual Planning Summary for National Nuclear Security Administration Service Center (NNSA-SC) 2010 Annual Planning Summary for Nevada Site Office Energy.gov Careers & Internships...

399

STANFORD LINEAR ACCELERATOR CENTER FY 2004 FY2010  

E-Print Network (OSTI)

of natural gas, compressed air, cooling-tower water, chilled water and hot water systems. These systems LF 3 sensors and PLC controllers at least two (2) out of four (4) cooling towers: 101, 1201, 1202 and 1701 therefore allowing optimizing the blow-down cycles. 27. Implement Title II design of campus cooling tower CT

Wechsler, Risa H.

400

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.

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

Some aspects of superconducting accelerator design  

SciTech Connect

The performance of an accelerator can be characterized by the efficiency with which electrical energy, the minimumm energy needed to generate a given beam voltage. The current accelerator improvement program at SLAC aims at raising the beam voltage to 50 GV which will use 240 klystrons each capable of producing a pulse 5 ..mu..s in length at a peak power of 36 MW. The Linear Collider requires 50 MW klystrons to achieve 60 GV which will raise the concomittant power consumption to 32.3 MW. We show that with superconducting elements we can increase the rf and ac conversion efficiencies and achieve the necessary 50 GV using only 1/3 of the present power requirements, provided that we exclude CW operation. We will further demonstrate that this increase in efficiency is crucial and highly significant in the design of a proposed 1000 GV linear accelerator.

Farkas, Z.D.; St. Lorant, S.J.

1982-11-01T23:59:59.000Z

402

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

403

Experimental Plans to Explore Dielectric Wakefield Acceleration in the THZ Regime  

SciTech Connect

Dielectric wakefield accelerators have shown great promise toward high-gradient acceleration. We investigate the performances of a possible experiment under consideration at the FLASH facility in DESY to explore wakefield acceleration with an enhanced transformer ratio. The experiment capitalizes on a unique pulse shaping capability recently demonstrated at this facility. In addition, the facility incorporates a superconducting linear accelerator that could generate bunch trains with closely spaced bunches thereby opening the exploration of potential dynamical effects in dielectric wakefield accelerators.

Lemery, F.; Mihalcea, D.; /Northern Illinois U.; Piot, P.; /Fermilab; Behrens, C.; Elsen, E.; Flottmann, K.; Gerth, C.; Kube, G.; Schmidt, B.; /DESY; Osterhoff, J.; /Hamburg U., Inst. Theor. Phys. II; Stoltz, P.

2011-09-07T23:59:59.000Z

404

High-energy lattice for first-beam operation of the SRF test accelerator at NML  

Science Conference Proceedings (OSTI)

The Superconducting Radio Frequency Test Accelerator, a linear electron accelerator currently in construction at Fermilab's New Muon Laboratory, will eventually reach energies of {approx} 900 MeV using four ILC-type superconducting accelerating cryomodules. The accelerator's construction is staged according to cryomodules availability. The first phase that will support first beam operation incorporates one cryomodule. In this Note, we summarize a possible design for the first-beam accelerator configuration.

Prokop, C.; /NICADD, DeKalb; Piot, P.; /NICADD, DeKalb /Fermilab; Church, M.; /Fermilab

2011-09-01T23:59:59.000Z

405

The Particle Adventure | How do we interpret our data? | The...  

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

evidence which supports the Standard Model. To summarize, physicists use accelerators to "peek" into the structure of particles. Detectors collect data which is then...

406

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

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

Accelerators and particle detectors - How do we detect what's happening? - The world's meterstick This image represents a meter stick measuring powers of ten. As you can see, there...

407

The Particle Adventure | How do we interpret our data? | Modern...  

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

Accelerators and particle detectors - How do we interpret our data? - Modern detectors Modern detectors consist of many different pieces of equipment which test for different...

408

Plasma beat-wave accelerator  

Science Conference Proceedings (OSTI)

We perform an analytic study of some quantities relevant to the plasma beat-wave accelerator (PBWA) concept. We obtain analytic expressions for the plasma frequency, longitudinal electron velocity, plasma density and longitudinal plasma electric field of a nonlinear longitudinal electron plasma oscillation with amplitude less than the wave-breaking limit and phase velocity approaching the speed of light. We also estimate the luminosity of a single-pass e/sup +/e/sup -/ linear PBWA collider assuming the energy and collision beamstrahlung are fixed parameters.

Noble, R.J.

1983-06-01T23:59:59.000Z

409

Wakefields in photonic accelerator structures  

SciTech Connect

Control and manipulation of properties - such as vacuum modal confinement, spatial harmonic content, phase velocity, and group velocity - are reasons why an all-dielectric beam-driven accelerator would be expected to benefit by borrowing from the field of optical bandgap photonics. We outline the general conditions for coherent Cerenkov radiation in a photonic crystal, illustrated by three examples: two Bragg mirrors separated by a vacuum gap, a woodpile with a linear waveguide channel, and a stack of photonic slabs having a planar waveguide channel.

Naranjo, B.; Andonian, G.; Arab, E.; Barber, S.; Fitzmorris, K.; Fukusawa, A.; Hoang, P.; Mahapatra, S.; O'Shea, B.; Valloni, A.; Williams, O.; Yang, C.; Rosenzweig, J. B. [UCLA Dept. of Physics and Astronomy, Los Angeles, CA 90095-1547 (United States)

2012-12-21T23:59:59.000Z

410

Physics considerations for laser-plasma linear colliders  

SciTech Connect

Physics considerations for a next-generation linear collider based on laser-plasma accelerators are discussed. The ultra-high accelerating gradient of a laser-plasma accelerator and short laser coupling distance between accelerator stages allows for a compact linac. Two regimes of laser-plasma acceleration are discussed. The highly nonlinear regime has the advantages of higher accelerating fields and uniform focusing forces, whereas the quasi-linear regime has the advantage of symmetric accelerating properties for electrons and positrons. Scaling of various accelerator and collider parameters with respect to plasma density and laser wavelength are derived. Reduction of beamstrahlung effects implies the use of ultra-short bunches of moderate charge. The total linac length scales inversely with the square root of the plasma density, whereas the total power scales proportional to the square root of the density. A 1 TeV center-of-mass collider based on stages using a plasma density of 10{sup 17} cm{sup -3} requires tens of J of laser energy per stage (using 1 {micro}m wavelength lasers) with tens of kHz repetition rate. Coulomb scattering and synchrotron radiation are examined and found not to significantly degrade beam quality. A photon collider based on laser-plasma accelerated beams is also considered. The requirements for the scattering laser energy are comparable to those of a single laser-plasma accelerator stage.

Schroeder, Carl; Esarey, Eric; Geddes, Cameron; Benedetti, Carlo; Leemans, Wim

2010-06-11T23:59:59.000Z

411

Use of dielectric material in muon accelerator RF cavities  

E-Print Network (OSTI)

The building of a muon collider is motivated by the desire to collide point-like particles while reducing the limitations imposed by synchrotron radiation. The many challenges unique to muon accelerators are derived from ...

French, Katheryn Decker

2011-01-01T23:59:59.000Z

412

Argonne Accelerator Institute  

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

GEM - GeV Electron Microtron (design report 1982) The GEM design report describes a novel six-sided CW microtron for accelerating electrons to 4 GeV. This accelerator design was...

413

Radiation from Kinetic Poynting Flux Acceleration  

E-Print Network (OSTI)

We derive analytic formulas for the power output and critical frequency of radiation by electrons accelerated by relativistic kinetic Poynting flux, and validate these results with Particle-In-Cell plasma simulations. We find that the in-situ radiation power output and critical frequency are much below those predicted by the classical synchrotron formulae. We discuss potential astrophysical applications of these results.

Edison Liang; Koichi Noguchi

2007-04-13T23:59:59.000Z

414

Accelerating Electric Vehicle Deployment | Department of Energy  

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

Accelerating Electric Vehicle Deployment Accelerating Electric Vehicle Deployment Accelerating Electric Vehicle Deployment Accelerating Electric Vehicle Deployment More Documents &...

415

Accelerators for heavy ion fusion  

SciTech Connect

Large fusion devices will almost certainly produce net energy. However, a successful commercial fusion energy system must also satisfy important engineering and economic constraints. Inertial confinement fusion power plants driven by multi-stage, heavy-ion accelerators appear capable of meeting these constraints. The reasons behind this promising outlook for heavy-ion fusion are given in this report. This report is based on the transcript of a talk presented at the Symposium on Lasers and Particle Beams for Fusion and Strategic Defense at the University of Rochester on April 17-19, 1985.

Bangerter, R.O.

1985-10-01T23:59:59.000Z

416

Accelerator technology for the Los Alamos ATW (accelerator transmutation of nuclear waste) system  

SciTech Connect

The Los Alamos concept for accelerator transmutation of nuclear waste (ATW) employs a high-power proton linear accelerator to generate intense fluxes of thermal neutrons (>10{sup 16} n/cm{sup 2}-s) through spallation on a lead-bismuth target. The nominal beam energy for an ATW accelerator is 1.6 GeV, with average current requirements ranging from 250 mA to 30 mA, depending on application specifics. A recent study of accelerator production of tritium (APT) led to the development of a detailed point design for a 1.6 GeV, 250 mA cw proton linac. The accelerator design was reviewed by the Energy Research Advisory Board (ERAB) and found to be technically sound. The Panel concluded that linac of this power level could now be implemented within the existing technology base, given an adequate component development program and an integrated engineering demonstration of the front end.

Lawrence, G.P.

1991-01-01T23:59:59.000Z

417

The beam business: Accelerators in industry  

SciTech Connect

Most physicists know that particle accelerators are widely used for treating cancer. But few are acquainted with the depth and breadth of their use in a myriad of applications outside of pure science and medicine. Society benefits from the use of particle beams in the areas of communications, transportation, the environment, security, health, and safety - in terms both of the global economy and quality of life. On the manufacturing level, the use of industrial accelerators has resulted in the faster and cheaper production of better parts for medical devices, automobiles, aircraft, and virtually all modern electronics. Consumers also benefit from the use of accelerators to explore for oil, gas, and minerals; sterilize food, wastewater, and medical supplies; and aid in the development of drugs and biomaterials.

Hamm, Robert W.; Hamm, Marianne E. [Pleasanton, California (United States)

2011-06-15T23:59:59.000Z

418

White Paper on DOE-HEP Accelerator Modeling Science Activities  

E-Print Network (OSTI)

Toward the goal of maximizing the impact of computer modeling on the design of future particle accelerators and the development of new accelerator techniques & technologies, this white paper presents the rationale for: (a) strengthening and expanding programmatic activities in accelerator modeling science within the Department of Energy (DOE) Office of High Energy Physics (HEP) and (b) increasing the community-wide coordination and integration of code development.

Vay, Jean-Luc; Koniges, Alice; Friedman, Alex; Grote, David P; Bruhwiler, David L

2013-01-01T23:59:59.000Z

419

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

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

she has to do is put the low-mass particles into an accelerator, give them a lot of kinetic energy (speed), and then collide them together. During this collision, the particle's...

420

The Particle Adventure | How do we interpret our data? | Quiz...  

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

Accelerators and particle detectors - How do we interpret our data? - Quiz - Particle tracks These next 6 event pictures are from a modern detector and show some of the possible...

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

What is an accelerator operator?  

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

is an accelerator operator? First I'll explain the education one must have in order to be considered for an Accelerator Operator position. Jefferson Lab's typical Accelerator...

422

Compton Spectrum from Poynting Flux Accelerated e+e- Plasma  

E-Print Network (OSTI)

We report the Compton scattering emission from the Poynting flux acceleration of electron- positron plasma simulated by the 2-1/2 dimensional particle-in-cell(PIC) code. We show these and other remarkable properties of Poynting flux acceleration and Compton spectral output, and discuss the agreement with the observed spectra of GRBs and XRFs.

Sugiyama, S; Noguchi, K; Takabe, H; Sugiyama, Shinya; Liang, Edison; Noguchi, Koichi; Takabe, Hideaki

2006-01-01T23:59:59.000Z

423

Compton Spectrum from Poynting Flux Accelerated e+e- Plasma  

E-Print Network (OSTI)

We report the Compton scattering emission from the Poynting flux acceleration of electron- positron plasma simulated by the 2-1/2 dimensional particle-in-cell(PIC) code. We show these and other remarkable properties of Poynting flux acceleration and Compton spectral output, and discuss the agreement with the observed spectra of GRBs and XRFs.

Shinya Sugiyama; Edison Liang; Koichi Noguchi; Hideaki Takabe

2006-04-18T23:59:59.000Z

424

RESONANCE BROADENING AND HEATING OF CHARGED PARTICLES IN MAGNETOHYDRODYNAMIC TURBULENCE  

SciTech Connect

The heating, acceleration, and pitch-angle scattering of charged particles by magnetohydrodynamic (MHD) turbulence are important in a wide range of astrophysical environments, including the solar wind, accreting black holes, and galaxy clusters. We simulate the interaction of high-gyrofrequency test particles with fully dynamical simulations of subsonic MHD turbulence, focusing on the parameter regime with {beta} {approx} 1, where {beta} is the ratio of gas to magnetic pressure. We use the simulation results to calibrate analytical expressions for test particle velocity-space diffusion coefficients and provide simple fits that can be used in other work. The test particle velocity diffusion in our simulations is due to a combination of two processes: interactions between particles and magnetic compressions in the turbulence (as in linear transit-time damping; TTD) and what we refer to as Fermi Type-B (FTB) interactions, in which charged particles moving on field lines may be thought of as beads sliding along moving wires. We show that test particle heating rates are consistent with a TTD resonance that is broadened according to a decorrelation prescription that is Gaussian in time (but inconsistent with Lorentzian broadening due to an exponential decorrelation function, a prescription widely used in the literature). TTD dominates the heating for v{sub s} >> v{sub A} (e.g., electrons), where v{sub s} is the thermal speed of species s and v{sub A} is the Alfven speed, while FTB dominates for v{sub s} << v{sub A} (e.g., minor ions). Proton heating rates for {beta} {approx} 1 are comparable to the turbulent cascade rate. Finally, we show that velocity diffusion of collisionless, large gyrofrequency particles due to large-scale MHD turbulence does not produce a power-law distribution function.

Lynn, Jacob W. [Physics Department, University of California, Berkeley, CA 94720 (United States); Parrish, Ian J.; Quataert, Eliot [Astronomy Department and Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States); Chandran, Benjamin D. G., E-mail: jacob.lynn@berkeley.edu [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)

2012-10-20T23:59:59.000Z

425

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.

426

Electron acceleration in solar noise storms  

E-Print Network (OSTI)

We present an up-to-date review of the physics of electron acceleration in solar noise storms. We describe the observed characteristics of noise storm emission, emphasizing recent advances in imaging observations. We briefly describe the general methodology of treating particle acceleration problems and apply it to the specific problem of electron acceleration in noise storms. We dwell on the issue of the efficiency of the overall noise storm emission process and outline open problems in this area. 1.1 Motivation: Noise storms are the most common form of meter wavelength radio emission from the solar corona. The nomenclature arises from hissing sounds produced in short-wave radio receivers, and was coined around the 1930s. Noise storms are sites of long-lasting quasi-continuous electron acceleration in the

Prasad Subramanian

2007-01-01T23:59:59.000Z

427

Relativistic Fermi acceleration with shock compressed turbulence  

E-Print Network (OSTI)

This paper presents numerical simulations of test particle Fermi acceleration at relativistic shocks of Lorentz factor Gamma_sh = 2-60, using a realistic downstream magnetic structure obtained from the shock jump conditions. The upstream magnetic field is described as pure Kolmogorov turbulence; the corresponding downstream magnetic field lies predominantly in the plane tangential to the shock surface and the coherence length is smaller along the shock normal than in the tangential plane. Acceleration is nonetheless efficient and leads to powerlaw spectra with index s = 2.6-2.7 at large shock Lorentz factor Gamma_sh >> 1, markedly steeper than for isotropic scattering downstream. The acceleration timescale t_acc in the upstream rest frame becomes a fraction of Larmor time t_L in the ultra-relativistic limit, t_acc ~ 10 t_L/Gamma_sh. Astrophysical applications are discussed, in particular the acceleration in gamma-ray bursts internal and external shocks.

Martin Lemoine; Benoit Revenu

2005-10-18T23:59:59.000Z

428

Levy-Student distributions for halos in accelerator beams  

SciTech Connect

We describe the transverse beam distribution in particle accelerators within the controlled, stochastic dynamical scheme of stochastic mechanics (SM) which produces time reversal invariant diffusion processes. This leads to a linearized theory summarized in a Schroedinger-like (SL) equation. The space charge effects have been introduced in recent papers by coupling this S-L equation with the Maxwell equations. We analyze the space-charge effects to understand how the dynamics produces the actual beam distributions, and in particular we show how the stationary, self-consistent solutions are related to the (external and space-charge) potentials both when we suppose that the external field is harmonic (constant focusing), and when we a priori prescribe the shape of the stationary solution. We then proceed to discuss a few other ideas by introducing generalized Student distributions, namely, non-Gaussian, Levy infinitely divisible (but not stable) distributions. We will discuss this idea from two different standpoints: (a) first by supposing that the stationary distribution of our (Wiener powered) SM model is a Student distribution; (b) by supposing that our model is based on a (non-Gaussian) Levy process whose increments are Student distributed. We show that in the case (a) the longer tails of the power decay of the Student laws and in the case (b) the discontinuities of the Levy-Student process can well account for the rare escape of particles from the beam core, and hence for the formation of a halo in intense beams.

Cufaro Petroni, Nicola; De Martino, Salvatore; De Siena, Silvio; Illuminati, Fabrizio [Dipartimento di Matematica dell'Universita di Bari and INFN Sezione di Bari, via E. Orabona 4, 70125 Bari (Italy); Dipartimento di Fisica dell'Universita di Salerno, INFM Unita di Salerno, and INFN Sezione di Napoli Gruppo collegato di Salerno, Via S. Allende, I-84081 Baronissi (Saudi Arabia) (Italy)

2005-12-15T23:59:59.000Z

429

SLAC National Accelerator Laboratory - Director of Accelerator...  

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

Committee on Appropriations asked the US Department of Energy (DOE) to submit a strategic plan for accelerator R&D by June 2012. The DOE asked me to lead a task force to...

430

Governance of the International Linear Collider Project  

SciTech Connect

Governance models for the International Linear Collider Project are examined in the light of experience from similar international projects around the world. Recommendations for one path which could be followed to realize the ILC successfully are outlined. The International Linear Collider (ILC) is a unique endeavour in particle physics; fully international from the outset, it has no 'host laboratory' to provide infrastructure and support. The realization of this project therefore presents unique challenges, in scientific, technical and political arenas. This document outlines the main questions that need to be answered if the ILC is to become a reality. It describes the methodology used to harness the wisdom displayed and lessons learned from current and previous large international projects. From this basis, it suggests both general principles and outlines a specific model to realize the ILC. It recognizes that there is no unique model for such a laboratory and that there are often several solutions to a particular problem. Nevertheless it proposes concrete solutions that the authors believe are currently the best choices in order to stimulate discussion and catalyze proposals as to how to bring the ILC project to fruition. The ILC Laboratory would be set up by international treaty and be governed by a strong Council to whom a Director General and an associated Directorate would report. Council would empower the Director General to give strong management to the project. It would take its decisions in a timely manner, giving appropriate weight to the financial contributions of the member states. The ILC Laboratory would be set up for a fixed term, capable of extension by agreement of all the partners. The construction of the machine would be based on a Work Breakdown Structure and value engineering and would have a common cash fund sufficiently large to allow the management flexibility to optimize the project's construction. Appropriate contingency, clearly apportioned at both a national and global level, is essential if the project is to be realised. Finally, models for running costs and decommissioning at the conclusion of the ILC project are proposed. This document represents an interim report of the bodies and individuals studying these questions inside the structure set up and supervised by the International Committee for Future Accelerators (ICFA). It represents a request for comment to the international community in all relevant disciplines, scientific, technical and most importantly, political. Many areas require further study and some, in particular the site selection process, have not yet progressed sufficiently to be addressed in detail in this document. Discussion raised by this document will be vital in framing the final proposals due to be published in 2012 in the Technical Design Report being prepared by the Global Design Effort of the ILC.

Foster, B.; /Oxford U.; Barish, B.; /Caltech; Delahaye, J.P.; /CERN; Dosselli, U.; /INFN, Padua; Elsen, E.; /DESY; Harrison, M.; /Brookhaven; Mnich, J.; /DESY; Paterson, J.M.; /SLAC; Richard, F.; /Orsay, LAL; Stapnes, S.; /CERN; Suzuki, A.; /KEK, Tsukuba; Wormser, G.; /Orsay, LAL; Yamada, S.; /KEK, Tsukuba

2012-05-31T23:59:59.000Z

431

Linearized gyro-kinetic equation  

SciTech Connect

An ordering of the linearized Fokker-Planck equation is performed in which gyroradius corrections are retained to lowest order and the radial dependence appropriate for sheared magnetic fields is treated without resorting to a WKB technique. This description is shown to be necessary to obtain the proper radial dependence when the product of the poloidal wavenumber and the gyroradius is large (k rho much greater than 1). A like particle collision operator valid for arbitrary k rho also has been derived. In addition, neoclassical, drift, finite $beta$ (plasma pressure/magnetic pressure), and unperturbed toroidal electric field modifications are treated. (auth)

Catto, P.J.; Tsang, K.T.

1976-01-01T23:59:59.000Z

432

Confined energy distribution for charged particle beams  

SciTech Connect

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

Jason, Andrew J. (Los Alamos, NM); Blind, Barbara (Los Alamos, NM)

1990-01-01T23:59:59.000Z

433

Linear Collider Collaboration Tech Notes  

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

5 08//00 5 08//00 Study of Beam Energy Spectrum Measurement in the NLC Extraction Line August 2000 Yuri Nosochkov and Tor Raubenheimer Stanford Linear Accelerator Center Stanford, CA Abstract: The NLC extraction line optics includes a secondary focal point with a very small _- function and 2 cm dispersion which can be used for measurement of outgoing beam energy spread. In this study, we performed tracking simulations to transport the NLC disrupted beam from the Interaction Point (IP) to the extraction line secondary focus (the IP image), `measure' the transverse beam pro_le at the IP image and reconstruct the beam energy spectrum. The resultant distribution was compared with the original energy spectrum at the IP. Study of Beam Energy Spectrum Measurement

434

Linear Collider Collaboration Tech Notes  

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

2 03/12/99 2 03/12/99 PEP-II RF Cavity Revisited December 3, 1999 R. Rimmer, G. Koehler, D. Li, N. Hartmann, N. Folwell, J. Hodgson, B. McCandless Lawrence Berkeley National Laboratory Stanford Linear Accelerator Center Berkeley, CA, USA Stanford, CA, USA Abstract: This report describes the results of numerical simulations of the PEP-II RF cavity performed after the completion of the construction phase of the project and comparisons are made to previous calculations and measured results. These analyses were performed to evaluate new calculation techniques for the HOM distribution and RF surface heating that were not available at the time of the original design. These include the use of a high frequency electromagnetic element in ANSYS and the new Omega 3P code to study wall

435

Linear Collider Collaboration Tech Notes  

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

4, 10/03/00 4, 10/03/00 Luminosity for NLC Design Variations March 10, 1999 K.A. Thompson and T.O. Raubenheimer Stanford Linear Accelerator Center Stanford, CA, USA Abstract: In this note we give Guineapig simulation results for the luminosity and luminosity spectrum of three baseline NLC designs at 0.5~TeV and 1.0~TeV and compare the simulation results with analytic approximations. We examine the effects of varying several design parameters away from the NLC-B-500 and NLC-B-1000 designs, in order to study possible trade-offs of parameters that could ease tolerances, increase luminosity, or help to optimize machine operation for specific physics processes. Luminosity for NLC Design Variations K.A. Thompson and T.O.Raubenheimer INTRODUCTION In this note we give Guineapig [l] simulation results for the luminosity and

436

Linear Collider Collaboration Tech Notes  

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

Notes Notes LCC - 0038 29/04/00 CBP Tech Note - 234 Transverse Field Profile of the NLC Damping Rings Electromagnet Wiggler 29 April 2000 17 J. Corlett and S. Marks Lawrence Berkeley National Laboratory M. C. Ross Stanford Linear Accelerator Center Stanford, CA Abstract: The primary effort for damping ring wiggler studies has been to develop a credible radiation hard electromagnet wiggler conceptual design that meets NLC main electron and positron damping ring physics requirements [1]. Based upon an early assessment of requirements, a hybrid magnet similar to existing designs satisfies basic requirements. However, radiation damage is potentially a serious problem for the Nd-Fe-B permanent magnet material, and cost remains an issue for samarium cobalt magnets. Superconducting magnet designs have not been

437

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

438

Argonne Accelerator Institute  

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

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

439

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

440

A CLASSIFICATION SCHEME FOR TURBULENT ACCELERATION PROCESSES IN SOLAR FLARES  

SciTech Connect

We establish a classification scheme for stochastic acceleration models involving low-frequency plasma turbulence in a strongly magnetized plasma. This classification takes into account both the properties of the accelerating electromagnetic field, and the nature of the transport of charged particles in the acceleration region. We group the acceleration processes as either resonant, non-resonant, or resonant-broadened, depending on whether the particle motion is free-streaming along the magnetic field, diffusive, or a combination of the two. Stochastic acceleration by moving magnetic mirrors and adiabatic compressions are addressed as illustrative examples. We obtain expressions for the momentum-dependent diffusion coefficient D(p), both for general forms of the accelerating force and for the situation when the electromagnetic force is wave-like, with a specified dispersion relation {omega} = {omega}(k). Finally, for models considered, we calculate the energy-dependent acceleration time, a quantity that can be directly compared with observations of the time profile of the radiation field produced by the accelerated particles, such as those occuring during solar flares.

Bian, Nicolas; Kontar, Eduard P. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Emslie, A. Gordon, E-mail: n.bian@physics.gla.ac.uk, E-mail: eduard@astro.gla.ac.uk, E-mail: emslieg@wku.edu [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States)

2012-08-01T23:59:59.000Z

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.


441

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

442

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

443

ACCELERATION RESPONSIVE SWITCH  

DOE Patents (OSTI)

An acceleration-responsive device with dual channel capabilities whereby a first circuit is actuated upon attainment of a predetermined maximum acceleration level and when the acceleration drops to a predetermined minimum acceleriltion level another circuit is actuated is described. A fluid-damped sensing mass slidably mounted in a relatively frictionless manner on a shaft through the intermediation of a ball bushing and biased by an adjustable compression spring provides inertially operated means for actuating the circuits. (AEC)

Chabrek, A.F.; Maxwell, R.L.

1963-07-01T23:59:59.000Z

444

Cosmic Accelerators: Engines of the Extreme Universe  

Science Conference Proceedings (OSTI)

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

445

Particle separation  

DOE Patents (OSTI)

Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

Moosmuller, Hans (Reno, NV); Chakrabarty, Rajan K. (Reno, NV); Arnott, W. Patrick (Reno, NV)

2011-04-26T23:59:59.000Z

<