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1

Helium Refrigeration System for BNL Colliding-Beam Accelerator  

SciTech Connect

A Helium Refrigeration System which will supply the cooling required for the Colliding Beam Accelerator at Brookhaven National Laboratory is under construction. Testing of the compressor system is scheduled for late 1983 and will be followed by refrigerator acceptance tests in 1984. The refrigerator has a design capacity of 24.8 kW at a temperature level near 4% while simultaneously producing 55 kW for heat shield loads at 55K. When completed, the helium refrigerator will be the world's largest. Twenty-five oil-injected screw compressors with an installed total of 23,250 horsepower will supply the gas required. One of the unique features of the cycle is the application of three centrifugal compressors used at liquid helium temperature to produce the low temperatures (2.5K) and high flow rates (4154 g/s) required for this service.

Brown, D.P.; Farah, Y.; Gibbs, R.J.; Schlafke, A.P.; Schneider, W.J.; Sondericker, J.H.; Wu, K.C.

1983-01-01

2

Production of high density proton currents for colliding beam accelerators  

Microsoft Academic Search

A head-on collision of two 15 GeV protons produces an energy in the centre of mass equivalent to about 500 GeV with the target at rest. To achieve significant production of secondaries, intense beams of particles are required, and this is obtained by `stacking' successive pulses of particles at high energy. Limitations imposed by the accelerating system are examined and

J. W. Burren; D. Morgan; W. Walkinshaw

1959-01-01

3

High Energy Accelerator and Colliding Beam User Group  

SciTech Connect

This report discusses research in the following areas: the study of e{sup +}e{sup {minus}} interactions; Hadron collider physics at Fermilab; fixed target physics and particle physics of general interest; and, the solenoidal detector collaboration at SSCL.

Snow, G.A.; Skuja, A.

1992-05-01

4

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

ScienceCinema

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

5

Acceleration for the ?+?- collider  

Microsoft Academic Search

We discuss possible acceleration scenarios and methods for a ? +-?- collider. The accelerator must take the beams from ~100 MeV to 2 TeV energies within the muon life-time (2.2×10-6E?\\/m? ?S), while compressing bunches of ~1012 muons from m to cm bunch lengths. A linac, recirculating linac, and very rapid-cycling synchrotron approaches are studied. A multiple recirculating linac approach is

D. Summers; D. Neuffer; Q.-S. Shu; E. Willen

1997-01-01

6

High energy accelerator and colliding beam user group  

SciTech Connect

This report discusses the following topics: OPAL experiment at LEP; D{phi} experiment at Fermilab; deep inelastic muon interactions at TEV II; CYGNUS experiment; final results from {nu}{sub e}{sup {minus}e} elastic scattering; physics with CLEO detector at CESR; results from JADE at PETRA; rare kaon-decay experiment at BNL; search for top quark; and super conducting super collider activities.

Not Available

1990-09-01

7

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.

2011-09-10

8

Colliding beams in a M{umlt o}bius accelerator  

SciTech Connect

An accelerator can be called {open_quote}{open_quote}M{umlt o}bius{close_quote}{close_quote} if it contains a {open_quote}{open_quote}twist{close_quote}{close_quote} element that forces a particle to complete two traversals of the ring before returning to a corresponding state. The resultant ring has properties very different from an untwisted lattice. Since chromaticity correction needs only to be performed in one plane, it can be done entirely in the (easy) horizontal plane, with {pi}-separated, non-interleaved, sextupole pairs. This permits increased focusing strength while preserving large amplitude stability. In colliding beam operation, the (round) beams are robust against beam-beam interaction. Simulation indicates that beams counter-rotating in the same chamber need not be separated even for accumulated small-amplitude tune shifts greatly exceeding one. The large resulting tune spreads are found to stabilize the beams against head-tail instability with greater-than-typical head-tail tune shifts. Since stabilization relies at present on synchrotron oscillations with chromaticity near zero, the sextupoles needed for this, and the large-amplitude degradation they cause, may be superfluous. Stable operation is possible with beam-beam tune shifts well in excess of 0.1 at the main experiment crossing points. {copyright} {ital 1996 American Institute of Physics.}

Talman, R. [Laboratory of Nuclear Studies, Cornell University, Ithaca, New York 14853 (United States)

1996-02-01

9

Beam-Beam Deflection as a Beam Tuning Tool at the SLAC (Stanford Linear Accelerator Center) Linear Collider.  

National Technical Information Service (NTIS)

To achieve maximum integrated luminosity at the SLAC Linear Collider, a method of noninvasive beam tuning is required. Traditional luminosity monitors based on Bhabha scattering are inadequate because of low instantaneous counting rates. Coherent deflecti...

W. Koska P. Bambade W. Kozanecki N. Phinney S. R. Wagner

1989-01-01

10

Design study of beam dynamics issues for 1 TeV next linear collider based upon the relativistic-klystron two-beam accelerator  

SciTech Connect

A design study has recently been conducted for exploring the feasibility of a relativistic-klystron two-beam accelerator (RK-TBA) system as a rf power source for a 1 TeV linear collider. The author present, in this paper, the beam dynamics part of this study. They have achieved in their design study acceptable transverse and longitudinal beam stability properties for the resulting high efficiency and low cost RK-TBA.

Li, H.; Goffeney, N.; Henestroza, E.; Sessler, A.; Yu, S. [Lawrence Berkeley Lab., CA (United States); Houck, T.; Westenskow, G. [Lawrence Livermore National Lab., CA (United States)

1994-11-01

11

Simulations of an acceleration scheme for producing high intensity and low emittance antiproton beam for Fermilab collider operation  

SciTech Connect

During Fermilab collider operation, the Main Injector (MI) provides high intensity and low emittance proton and antiproton beams for the Tevatron. The present coalescing scheme for antiprotons in the Main Injector yields about a factor of two increase in the longitudinal emittance and a factor of 5% to 20% decrease in intensity before injection to the Tevatron. In order to maximize the integrated luminosity delivered to the collider experiments, it is important to minimize the emittance growth and maximize the intensity of the MI beam. To this end, a new scheme using a combination of 2.5 MHz and 53 MHz accelerations has been developed and tested. This paper describes the full simulation of the new acceleration scheme, taking account of space charge, 2.5 MHz and 53 MHz beam loading, and the effect of residual 53 MHz rf voltage during 2.5 MHz acceleration and rf manipulations. The simulations show the longitudinal emittance growth at the 10% level with no beam loss. The experimental test of the new scheme is reported in another PAC05 paper.

Wu, Vincent; Bhat, C.M.; MacLachlan, J.A.; /Fermilab

2005-05-01

12

Beam collimation at hadron colliders  

SciTech Connect

Operational and accidental beam losses in hadron colliders can have a serious impact on machine and detector performance, resulting in effects ranging from minor to catastrophic. Principles and realization are described for a reliable beam collimation system required to sustain favorable background conditions in the collider detectors, provide quench stability of superconducting magnets, minimize irradiation of accelerator equipment, maintain operational reliability over the life of the machine, and reduce the impact of radiation on personnel and the environment. Based on detailed Monte-Carlo simulations, such a system has been designed and incorporated in the Tevatron collider. Its performance, comparison to measurements and possible ways to further improve the collimation efficiency are described in detail. Specifics of the collimation systems designed for the SSC, LHC, VLHC, and HERA colliders are discussed.

Nikolai V. Mokhov

2003-08-12

13

Accelerator Structures for Linear Colliders  

SciTech Connect

Linear Colliders require high gradient (to reduce length dependent costs), high shunt impedance (to reduce power dependent costs) accelerator structures in which the long range dipole wakefields have been reduced by 2 to 3 orders of magnitude. The precise dipole wake reduction factor required depends on many factors. These include the beam intensity and time structure, the accelerator aperture and accelerating gradient, the strength of the focusing, the alignment precision and position stability of accelerator structures and the focusing elements, the effectiveness of the tuning procedure and feedback system, the pulse to pulse stability of the injected beam, and the required emittance at the final focus. For the purposes of this paper the authors accept that large reduction factors are required and discuss various approaches to achieving them. There are basically two approaches: detuning and damping, which are often used in combination. Damping can be accomplished either by introducing loss selectively into the accelerating structure cells, or by coupling the dipole modes out of the accelerating region and absorbing them in external loads or lossy materials. Detuning can greatly reduce the amount of damping required by causing the dipole modes to decohere, and it is possible to achieve destructive interference so that the wakefields from different cells in the accelerator cancel each other as seen by the bunches of electrons travelling through the linac. Several different approaches have achieved large reduction in the long-range dipole wakefields so that they pose no restriction on the length of the bunch trains which can be used for linear colliders.

Miller, Roger H.

2000-09-15

14

Tetrahedral colliding beam nuclear fusion  

US Patent & Trademark Office Database

The subject invention is a nuclear fusion reactor. It operates by colliding particle beams from at least four different directions. The beams collide in a matrix that guides the particles to the reaction's center by their mutual electrostatic repulsion. In the preferred embodiment the reactor comprises primarily four high energy particle accelerators (11a, 11b, 11c, and 11d). At the reactor's center, the accelerators' four beams intersect at angles of approximately 109.471220634491 degrees. The exact measure of the preferred angle is given by the measure of the obtuse interior angle of an isosceles triangle that has two sides measuring the square root of three units and a base measuring twice the square root of two units. Accelerated to fusion producing velocities, the four particle beams intersect in a high-vacuum reaction chamber (12). The resulting collision matrix funnels the accelerated particles into the center of the reaction zone causing some of the fuel particles to fuse rather than to scatter. This reactor's collision matrix should result in a higher collision rate than that of previous non-neutralized beam-beam reactors. When the reactor is inducing fusion with lightweight elements such as deuterium, energy is released, although not necessarily more energy than it consumes. This reactor is inherently safe in that it cannot melt down or explode. Since the fuel for fusion is cheap and in virtually unlimited supply this reactor or some future improvement of its design could possibly yield virtually unlimited power.

1998-10-20

15

The Next Linear Collider Test Accelerator  

Microsoft Academic Search

During the past several years, there has been tremendous progress on the development of the RF system and accelerating structures for a Next Linear Collider (NLC). Developments include high-power klystrons, RF pulse compression systems and damped\\/detuned accelerator structures to reduce wakefields. In order to integrate these separate development efforts into an actual X-band accelerator capable of accelerating the electron beams

R. D. Ruth; C. Adolphsen; K. Bane; R. F. Boyce; D. L. Burke; R. Callin; G. Caryotakis; R. Cassel; S. L. Clark; H. Deruyter; K. Fant; R. Fuller; S. Heifets; H. Hoag; R. Humphrey; S. Kheifets; R. Koontz; N. M. Kroll; R. T. Lavine; G. A. Loew; A. Menegat; R. H. Miller; C. Nantista; J. M. Paterson; C. Pearson; R. Phillips; J. Rifkin; J. Spencer; S. Tantawi; K. A. Thompson; A. Vlieks; V. Vylet; J. W. Wang; P. B. Wilson; A. Yeremian; B. Youngman

1993-01-01

16

High Energy Accelerator and Colliding Beam User Group. Progress report, March 1, 1992--October 31, 1992  

SciTech Connect

This report discusses research in the following areas: the study of e{sup +}e{sup {minus}} interactions; Hadron collider physics at Fermilab; fixed target physics and particle physics of general interest; and, the solenoidal detector collaboration at SSCL.

Snow, G.A.; Skuja, A.

1992-05-01

17

Beam rounders for circular colliders  

SciTech Connect

By means of linear optics, an arbitrary uncoupled beam can be locally transformed into a round (rotation-invariant) state and then back. This provides an efficient way to round beams in the interaction region of circular colliders.

A. Burov and S. Nagaitsev

2002-12-10

18

THE TWO-BEAM ACCELERATOR  

SciTech Connect

A Two-Beam Accelerator, in which one of the beams is an intense low energy beam made to undergo free electron lasing and the other beam is a compact bunch of high energy electrons, is shown to be an interesting possibility for a linear collider.

Hopkins, D.B.; Sessler, A.M.; Wurtele, J.S.

1984-04-01

19

The Next Linear Collider Test Accelerator  

SciTech Connect

During the past several years, there has been tremendous progress on the development of the RF system and accelerating structures for a Next Linear Collider (NLC). Developments include high-power klystrons, RF pulse-compression systems and damped/detuned accelerator structures to reduce wakefields. In order to integrate these separate development efforts into an actual X-band accelerator capable of accelerating the electron beams necessary for an NLC, we plan to build an NLC Test Accelerator (NLCTA). The goal of the NLCTA is to bring together all elements of the entire accelerating system by constructing. and reliably operating an engineered model of a high-gradient linac suitable for the NLC. The NLCTA win serve as a test-bed as the design of the NLC evolves and will provide a model upon which a reliable cost estimate can be based. In addition to testing the RF acceleration system, the NLCTA will be able to address many questions related to the dynamics of the beam during acceleration. In this paper, we will report on the status of the design and component development for the NLC Test Accelerator.

Paterson, J.M.; Ruth, R.D.; Adolphsen, C.; Bane, K.L.; Burke, D.L.; Callin, R.S.; Caryotakis, G.; Cassel, R.L.; Clark, S.L.; Deruyter, H.; Fant, K.; Fuller, R.W.; Heifets, S.A.; Hoag, H.A.; Humphrey, R.; Keicher, A.J.; Kheifets, S.; Koontz, R.F.; Lavine, T.L.; Loew, G.A.; Menegat, A.; Miller, R.H.; Nordby, M.E.; Pearson, C.; Rifkin, J.; Spencer, J.; Tantawi, S.G.; Thompson, K.A.; Vlieks, A.E.; Vylet, V.; Wang, J.W.; Wilson, P.B.; Yeremian, A.D.; Youngman, B. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Kroll, N.M. [California Univ., San Diego, CA (United States); Nantista, C. [California Univ., Los Angeles, CA (United States)

1992-09-01

20

The Next Linear Collider Test Accelerator  

SciTech Connect

During the past several years, there has been tremendous progress the development of the RF system and accelerating structures for a Next Linear Collider (NLC). Developments include high-power klystrons, RF pulse compression systems and damped/detuned accelerator structures to reduce wakefields. In order to integrate these separate development efforts into an actual X-band accelerator capable of accelerating the electron beams necessary for an NLC, we are building an NLC Test Accelerator (NLCTA). The goal of the NLCTA is to bring together all elements of the entire accelerating system by constructing and reliably operating an engineered model of a high-gradient linac suitable for the NLC. The NLCTA will serve as a testbed as the design of the NLC evolves. In addition to testing the RF acceleration system, the NLCTA is designed to address many questions related to the dynamics of the beam during acceleration. In this paper, we will report oil the status of the design, component development, and construction of the NLC Test Accelerator.

Ruth, R.D.; Adolphsen, C.; Bane, K. [and others

1993-04-01

21

Beam instabilities in very large hadron collider  

SciTech Connect

The Very Large Hadron Collider (VLHC) is a supercon-ducting proton-proton collider with approximately 100 TeV cm and approximately 10{sup 34} s{sup -1}cm{sup -2} luminosity [1]. Currently, beam dynamics in this future accelerator is the subject of intensive studies within the framework of the US-wide VLHC R&D program. This presentation sum-marizes recent developments in the field. Besides general discussion on relevant VLHC parameters, we consider various beam instabilities and ways to avoid them. Finally, we outline possibilities for theoretical and experimental R&D.

J. Marriner; V. Danilov; V. Shiltsev

1999-05-11

22

Accelerator physics of the Stanford Linear Collider and SLC accelerator experiments towards the Next Linear Collider  

SciTech Connect

The Stanford Linear Collider (SLC) was built to collide single bunches of electrons and positrons head-on at a single interaction point with single beam energies up to 55 GeV. The small beam sizes and high currents required for high luminosity operation have significantly pushed traditional beam quality limits. The Polarized Electron Source produces about 8 {times} 10{sup 10} electrons in each of two bunches with up to 28% polarization,. The Damping Rings provide coupled invariant emittances of 1.8 {times} 10{sup {minus}5} r-m with 4.5 {times} 10{sup 10} particles per bunch. The 57 GeV Linac has successfully accelerated over 3 {times} 10{sup 10} particles with design invariant emittances of 3 {times} 10{sup {minus}5} r-m. Both longitudinal and transverse wakefields affect strongly the trajectory and emittance corrections used for operations. The Arc systems routinely transport decoupled and betatron matched beams. In the Final Focus, the beams are chromatically corrected and demagnified producing spot sizes of 2 to 3 {mu}m at the focal point. Spot sizes below 2 {mu}m have been made during special tests. Instrumentation and feedback systems are well advanced, providing continuous beam monitoring and pulse-by-pulse control. A luminosity of 1.6 {times} 10{sup 29} cm{sup {minus}2}sec{sup {minus}1} has been produced. Several experimental tests for a Next Linear Collider (NLC) are being planned or constructed using the SLC accelerator as a test facility. The Final Focus Test Beam will demagnify a flat 50 GeV electron beam to dimensions near 60 nm vertically and 900 nm horizontally. A potential Emittance Dynamics Test Area has the capability to test the acceleration and transport of very low emittance beams, the compression of bunch lengths to 50 {mu}m, the acceleration and control of multiple bunches, and the properties of wakefields in the very short bunch length regime.

Seeman, J.T.

1992-06-01

23

Evaluation of round colliding beams for Tevatron  

SciTech Connect

This paper presents investigation of round beams for increasing the luminosity in colliders. The main idea of round beams is briefly discussed. Numerical simulations of round colliding beams for the Tevatron are much in favor of round beams, because they provide reduction of harmful impact of beam-beam forces on beam sizes particles diffusion and better stability with respect to errors and imperfections.

Danilov, V.V.

1997-06-11

24

Beam-beam issues in asymmetric colliders  

SciTech Connect

We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

Furman, M.A.

1992-07-01

25

Generating high-brightness electron beams via ionization injection by transverse colliding lasers in a plasma-wakefield accelerator.  

PubMed

The production of ultrabright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional particle-in-cell simulations. The relatively low intensity lasers are polarized along the wake axis and overlap with the wake for a very short time. The result is that the residual momentum of the ionized electrons in the transverse plane of the wake is reduced, and the injection is localized along the propagation axis of the wake. This minimizes both the initial thermal emittance and the emittance growth due to transverse phase mixing. Simulations show that ultrashort (~8 fs) high-current (0.4 kA) electron bunches with a normalized emittance of 8.5 and 6 nm in the two planes, respectively, and a brightness of 1.7×10(19) A rad(-2) m(-2) can be obtained for realistic parameters. PMID:23863007

Li, F; Hua, J F; Xu, X L; Zhang, C J; Yan, L X; Du, Y C; Huang, W H; Chen, H B; Tang, C X; Lu, W; Joshi, C; Mori, W B; Gu, Y Q

2013-07-01

26

Beam dynamics issues in linear colliders  

SciTech Connect

The primary goal of present and future linear colliders is to maximize the integrated luminosity for the experimental program. Beam dynamics plays a central role in the maximization of integrated luminosity. It is the major issue in the production of small beam sizes and low experimental backgrounds and is also an important factor in the production of particle numbers, in the acceleration process, and in the number of bunches. The beam dynamics effects on bunches which are extracted from the damping rings, accelerated in the linac, collimated, momentum analyzed, and finally delivered to the final focus are reviewed. The effects of bunch compression, transverse and longitudinal wakefields, BNS damping, energy definition, dispersion, emittance, bunch aspect ratio, feedback, and stability are all important. 11 refs., 1 tab.

Seeman, J.T.

1989-06-01

27

Beam dynamics issues in linear colliders  

NASA Astrophysics Data System (ADS)

The primary goal of present and future linear colliders is to maximize the integrated luminosity for the experimental program. Beam dynamics plays a central role in the maximization of integrated luminosity. It is the major issue in the production of small beam sizes and low experimental backgrounds and is also an important factor in the production of particle numbers, in the acceleration process, and in the number of bunches. The beam dynamics effects on bunches which are extracted from the damping rings, accelerated in the linac, collimated, momentum analyzed, and finally delivered to the final focus are reviewed. The effects of bunch compression, transverse and longitudinal wakefields, BNS damping, energy definition, dispersion, emittance, bunch aspect ratio, feedback, and stability are all important.

Seeman, John T.

1989-06-01

28

Linear accelerators for TeV colliders  

SciTech Connect

This paper summarizes four tutorial lectures on linear electron accelerators: Electron Linacs for TeV Colliders, Emittance and Damping Rings, Wake Fields: Basic Concepts, and Wake Field Effects in Linacs.

Wilson, P.B.

1985-05-01

29

A test accelerator for the next linear collider  

SciTech Connect

At SLAC, the authors are pursuing the design of a Next Linear Collider (NLC) which would begin with a center-of-mass energy of 0.5 TeV, and be upgradable to at least 1.0 TeV. To achieve this high energy, they have been working on the development of a high-gradient 11.4-GHz (X-band) linear accelerator for the main linac of the collider. In this paper, they present the design of a {open_quotes}Next Linear Collider Test Accelerator{close_quotes} (NLCTA). The goal of the NLCTA is to incorporate the new technologies of X-band accelerator structures, RF pulse compression systems and klystrons into a short linac which will then be a test bed for beam dynamics issues related to high-gradient acceleration.

Ruth, R.D.; Adolphsen, C.; Bane, K.; Boyce, R.F.; Burke, D.L.; Callin, R.; Caryotakis, G.; Cassel, R.; Clark, S.L.; Deruyter, H.; Fant, K.; Fuller, R.; Heifets, S.; Hoag, H.; Humphrey, R.; Kheifets, S.; Koontz, R.; Lavine, T.; Loew, G.A.; Menegat, A.; Miller, R.H.; Paterson, J.M.; Pearson, C.; Phillips, R.; Rifkin, J.; Spencer, J.; Tantawi, S.; Thompson, K.A.; Vlieks, A.; Vylet, V.; Wang, J.W.; Wilson, P.B.; Yeremian, A.; Youngman, B. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Kroll, N.M. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)]|[California Univ., San Diego, CA (United States); Nantista, C. [California Univ., Los Angeles, CA (United States)

1993-07-01

30

The Next Linear Collider test accelerator: Status and results  

SciTech Connect

At SLAC, the authors are pursuing the design of a Next Linear Collider (NLC) which would begin with a center-of-mass energy of 0.5 TeV, and would be upgradable to 1.0 TeV and beyond. To achieve this high energy, for the past several years they have been working on the development of a high-gradient 11.4-GHz (X-band) linear accelerator for the main linac of the collider. In this paper, they present the status and initial results from the ``Next Linear Collider Test Accelerator`` (NLCTA). The goal of the NLCTA is to model the high gradient linac of the NLC. It incorporates the new technologies of X-band accelerator structures, rf pulse compression systems and high-power klystrons into a 0.5 to 1.0 GeV linac which is a test bed for beam dynamics issues related to high-gradient acceleration.

Ruth, R.D.

1996-06-01

31

High frequency planar accelerating structures for future linear colliders  

SciTech Connect

Modern microfabrication techniques based on deep etch x-ray lithography, e.g., LIGA, can be used to produce large-aspect-ratio, metallic or dielectric, planar structures suitable for high-frequency RF acceleration of charged particle beams. Specifically, these techniques offer significant advantages over conventional manufacturing methods for future linear colliders (beyond NLC, the Next Linear Collider) because of several unique systems requirements. First, to have the required ac wall plug power within reasonable limits, such future linear colliders (5 TeV) must operate at high frequency (30 GHz). Secondly, luminosity requirements suggest the use of multi-bunch acceleration of electrons and positrons in the linear collider. Thirdly, in order to clearly discriminate physics events in the final interaction point at which electrons and positrons collide, it is required that secondary particle production from beamstrahlung be minimized. Flat electron and positron beams with a large aspect ratio will be beneficial in reducing beamstrahlung in the final focus region, but cause the beam to be more sensitive to wakefields in the vertical dimension. In principle, a flat beam can be accelerated in a planar structure with reduced wakefield in the vertical direction for the entire length of the accelerator. The LIGA process is particularly suitable for manufacturing miniaturized, planar, asymmetric cavities at high frequency. The main advantages of the LIGA process are fabrication of structures with high aspect ratio, small dimensional tolerances, and arbitrary mask shape (cross-section). Other advantages include mass-production with excellent repeatability and precision of up to an entire section of an accelerating structure consisting of a number of cells. It eliminates the need of tedious machining and brazing, for example, of individual disks and cups in conventional disk-loaded structures. Also, planar input/output couplers for the accelerating structure can be easily machined in the same process with the cavities. The new fabrication technique should substantially reduce the manufacturing cost of such accelerating structures.

Yu, D.; Ben-Menahem, S. [DULY Research Inc., Rancho Palos Verdes, CA (United States); Wilson, P.; Miller, R.; Ruth, R. [Stanford Univ., CA (United States). Stanford Linear Accelerator Center; Nassiri, A. [Argonne National Lab., IL (United States)

1994-12-31

32

Future Accelerators, Muon Colliders, and Neutrino Factories  

SciTech Connect

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

Richard A Carrigan, Jr.

2001-12-19

33

Acceleration stages for a muon collider  

Microsoft Academic Search

Using muons in high energy colliders has an advantage in that the muons emit negligible synchrotron radiation, but has the disadvantage that the lifetime of the muons is very short. The latter requires that the muons be accelerated as rapidly as possible to prevent particle loss. The former allows one to loop back and pass through the same linac multiple

J. S. Berg; A. A. Harren; J. E. Griffin; C. Johnstone; F. E. Mills; A. Moretti; D. V. Neuffer; W. Wan; R. B. Palmer; D. Summers

1999-01-01

34

Engineering conceptual design of the relativistic Klystron two-beam accelerator based power source for 1-TeV next linear collider  

SciTech Connect

Ultra-high gradient radio frequency linacs require efficient and reliable power sources. The induction linac has proven to be a reliable source of low energy, high current and high brightness electron beams. The low energy beam is bunched, transported through resonant transfer cavities in which it radiates microwave energy that is coupled to an adjacent high energy accelerator. The low energy beam is maintained at a constant energy by periodic induction accelerator cells. This paper describes the engineering aspects of the induction accelerator based relativistic klystron. The physics issues are covered in another paper at this conference.

Reginato, L.; Deadrick, F.; Peters, C.; Vanecek, D.; Yu, S.

1995-04-01

35

GPU-optimized Code for Long-term Simulations of Beam-beam Effects in Colliders  

SciTech Connect

We report on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, a previously computationally prohibitive long-term simulations become tractable. We use the new code to model the proposed medium-energy electron-ion collider (MEIC) at Jefferson Lab.

Roblin, Yves [JLAB; Morozov, Vasiliy [JLAB; Terzic, Balsa [JLAB; Aturban, Mohamed A. [Old Dominion University; Ranjan, D. [Old Dominion University; Zubair, Mohammed [Old Dominion University

2013-06-01

36

PIC Simulations of Colliding Pulse Injection for Laser Wakefield Acceleration  

NASA Astrophysics Data System (ADS)

The use of colliding laser pulses to control the injection of plasma electrons into the plasma wake of a laser wakefield accelerator (LWFA) is a promising approach to obtaining GeV scale electron bunches with orders of magnitude smaller emittance and energy spread. Colliding pulse injection (CPI) is being explored experimentally by groups around the world. We will present recent particle-in-cell (PIC) simulations of colliding pulse injection, using the parallel VORPAL framework, for physical parameters relevant to ongoing experiments of the LOASIS Program at Lawrence Berkeley Laboratory. The details of how particle trapping starts and stops, in the presence of counter-propagating laser pulses and nonlinear beam loading, is sensitive to noise and other errors in the PIC simulation. Hence, we will present results of different algorithmic choices, including high-order particle shapes and spatial smoothing.

Bruhwiler, David; Cowan, Ben; Paul, Kevin; Cary, John; Geddes, Cameron; Cormier-Michelle, Estelle; Esarey, Eric; Schroeder, Carl; Leemans, Wim

2009-11-01

37

Two-Beam Accelerator.  

National Technical Information Service (NTIS)

The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple m...

A. M. Sessler D. B. Hopkins

1986-01-01

38

Two-Beam Accelerator.  

National Technical Information Service (NTIS)

The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple m...

A. M. Sessler D. B. Hopkins

1987-01-01

39

The accuracy of beam-beam diagnostics for circular colliders  

SciTech Connect

We investigate the potential of beam-beam deflection techniques for the determination of spot sizes, tilt angle, centering, and angular divergence for circular colliders. Achievable accuracies for all measured quantities are estimated.

Ziemann, V.

1992-08-01

40

Advances in beam physics and technology: Colliders of the future  

SciTech Connect

Beams may be viewed as directed and focussed flow of energy and information, carried by particles and electromagnetic radiation fields (ie, photons). Often, they interact with each other (eg, in high energy colliders) or with other forms of matter (eg, in fixed targets, sychrotron radiation, neutron scattering, laser chemistry/physics, medical therapy, etc.). The whole art and science of beams revolve around the fundamental quest for, and ultimate implementation of, mechanisms of production, storage, control and observation of beams -- always directed towards studies of the basic structures and processes of the natural world and various practical applications. Tremendous progress has been made in all aspects of beam physics and technology in the last decades -- nonlinear dynamics, superconducting magnets and rf cavities, beam instrumentation and control, novel concepts and collider praradigms, to name a few. We illustrate this progress with a few examples and remark on the emergence of new collider scenarios where some of these progress might come to use -- the Gamma-Gamma Collider, the Muon Collider, laser acceleration, etc. We close with an outline of future oppotunities and outlook.

Chattopadhyay, S.

1994-11-01

41

Studies of beam dynamics in relativistic klystron two- beam accelerators  

Microsoft Academic Search

Two-beam accelerators (TBAs) based upon free-electron lasers (FELs) or relativistic klystrons (RK-TBAs) have been proposed as efficient power sources for next generation high-energy linear colliders. Studies have demonstrated the possibility of building TBAs from X-band (~8-12 GHz) through Ka-band (~30-35 GHz) frequency regions. A new method of simulating the beam dynamics in accelerators of this type has been developed in

Steven Michael Lidia; Steven M

1999-01-01

42

Electron injection and emittance control by transverse colliding pulses in a laser-plasma accelerator  

NASA Astrophysics Data System (ADS)

A method to inject electron beams with controllable transverse emittances in a laser-plasma accelerators is proposed and analyzed. It uses two colliding laser pulses that propagate transversely to the plasma wave. For colliding pulses with equal frequencies, a beam with very low emittance is generated when the collision is close to the density peak of the plasma wave. Electrons near the axis are accelerated longitudinally by the ponderomotive force of the colliding pulses, accelerated transversely by the beat wave, and subsequently injected into the second bucket of the wake. Ionization is used to increase the transverse injection area and the final trapped charge. Simulations show that the transverse emittance can be less than the 0.1 mm mrad level, which is important for many applications. For colliding laser pulses with different frequencies, the beat wave can produce asymmetric injection, which can enhance betatron radiation generated by the electron beam.

Chen, M.; Esarey, E.; Geddes, C. G. R.; Cormier-Michel, E.; Schroeder, C. B.; Bulanov, S. S.; Benedetti, C.; Yu, L. L.; Rykovanov, S.; Bruhwiler, D. L.; Leemans, W. P.

2014-05-01

43

Beam instrumentation for the Tevatron Collider  

SciTech Connect

The Tevatron in Collider Run II (2001-present) is operating with six times more bunches and many times higher beam intensities and luminosities than in Run I (1992-1995). Beam diagnostics were crucial for the machine start-up and the never-ending luminosity upgrade campaign. We present the overall picture of the Tevatron diagnostics development for Run II, outline machine needs for new instrumentation, present several notable examples that led to Tevatron performance improvements, and discuss the lessons for future colliders.

Moore, Ronald S.; Jansson, Andreas; Shiltsev, Vladimir; /Fermilab

2009-10-01

44

Beam stability issues in very large hadron collider  

NASA Astrophysics Data System (ADS)

The Very Large Hadron Collider (VLHC) is a superconducting proton-proton collider with approximately 100 TeV c.m. energy and approximately 10 34 s-1 cm-2 luminosity [G. Dugan, in: Proceedings of the 1999 IEEE Particle Acceleration Conference, New York, 1999, p. 48.] Currently, beam dynamics in this future accelerator is the subject of intensive studies within the framework of the US-wide VLHC R&D program. This presentation summarizes recent developments in the field. Besides general discussion on relevant VLHC parameters, we consider various beam instabilities and ways to avoid them. Finally, we outline possibilities for theoretical and experimental R&D. VLHC Web page http://vlhc.org.

Burov, A.; Marriner, J.; Shiltsev, V.; Danilov, V.; Lambertson, G.

2000-08-01

45

Simulations of high disruption colliding beams  

SciTech Connect

Recent B-factory proposals that use a linac beam colliding with the beam from a storage ring to achieve high luminosities (L > 10{sup 34} cm{sup {minus}2}sec{sup {minus}1}) result in very high disruption of the linac beam. The effects of such high disruption have been studied using the relativistic, 3-D code SWARM. We discuss the assumptions, parameters, and results of a series of runs that model such collisions. Regimes of high beam loss and methods to avoid them are also discussed. 5 refs., 4 figs.

Boyce, J.R.; Heifets, S.; Krafft, G.A.

1990-09-01

46

Beam Dynamics Issues in Linear Colliders.  

National Technical Information Service (NTIS)

The primary goal of present and future linear colliders is to maximize the integrated luminosity for the experimental program. Beam dynamics plays a central role in the maximization of integrated luminosity. It is the major issue in the production of smal...

J. T. Seeman

1989-01-01

47

Status and results from the next linear collider test accelerator  

SciTech Connect

The design for the Next Linear Collider (NLC) at SLAC is based on two 11.4 GHz linacs operating at an unloaded acceleration gradient of 50 MV/m increasing to 85 MV/m as the energy is increased from {1/2} TeV to 1 TeV in the center of mass. During the past several years there has been tremendous progress on the development of 11.4 GHz (X-band) RF systems. These developments include klystrons which operate at the required power and pulse length, pulse compression systems that achieve a factor of four power multiplication and structures that are specially designed to reduce long-range wakefields. Together with these developments, we have constructed a {1/2} GeV test accelerator, the NLC Test Accelerator (NLCTA). The NLCTA will serve as a test bed as the design of the NLC is refined. In addition to testing the RF system, the NLCTA is designed to address many questions related to the dynamics of the beam during acceleration, in particular the study of multibunch beam loading compensation and transverse beam break-up. In this paper we present the status of the NLCTA and the results of initial commissioning.

Ruth, R.D.; Adolphsen, C.; Allison, S. [and others

1996-08-01

48

Beam Instrumentation Challenges at the International Linear Collider  

SciTech Connect

The International Linear Collider (ILC) is a proposed facility for the study of high energy physics through electron-positron collisions at center-of-mass energies up to 500 GeV and luminosities up to 2 x 10{sup 34} cm{sup -2} sec{sup -1}. Meeting the ILC's goals will require an extremely sophisticated suite of beam instruments for the preservation of beam emittance, the diagnosis of optical errors and mismatches, the determination of beam properties required for particle physics purposes, and machine protection. The instrumentation foreseen for the ILC is qualitatively similar to equipment in use at other accelerator facilities in the world, but in many cases the precision, accuracy, stability, or dynamic range required by the ILC exceed what is typically available in today's accelerators. In this paper we survey the beam instrumentation requirements of the ILC and describe the system components which are expected to meet those requirements.

Tenenbaum, Peter; /SLAC

2006-05-16

49

Colliding beam physics at Fermilab: interaction regions, beam storage, antiproton cooling, production, and colliding  

SciTech Connect

The purpose of the colliding beams experment department at Fermilab was to bring about collisions of the stored beams in the energy doubler/saver and main ring, and construct experimental areas with appropriate detectors. To explore the feasibility of using the main ring as a storage device, several studies were carried out to investigate beam growth, loss, and the backgrounds in detectors at possible intersection regions. This range of developments constituted the major topics at the 1977 Summer Study reported here. Emphasis in part one is on interaction regions, beam storage, antiproton cooling, production, and colliding. 40 papers from this part are included in the data base. (GHT)

Walker, J.K. (ed.)

1977-01-01

50

Importance of beam-beam tune spread to collective beam-beam instability in hadron colliders.  

PubMed

In hadron colliders, electron-beam compensation of beam-beam tune spread has been explored for a reduction of beam-beam effects. In this paper, effects of the tune-spread compensation on beam-beam instabilities were studied with a self-consistent beam-beam simulation in model lattices of Tevatron and Large Hodron Collider. It was found that the reduction of the tune spread with the electron-beam compensation could induce a coherent beam-beam instability. The merit of the compensation with different degrees of tune-spread reduction was evaluated based on beam-size growth. When two beams have a same betatron tune, the compensation could do more harm than good to the beams when only beam-beam effects are considered. If a tune split between two beams is large enough, the compensation with a small reduction of the tune spread could benefit beams as Landau damping suppresses the coherent beam-beam instability. The result indicates that nonlinear (nonintegrable) beam-beam effects could dominate beam dynamics and a reduction of beam-beam tune spread by introducing additional beam-beam interactions and reducing Landau damping may not improve the stability of beams. PMID:15089423

Jin, Lihui; Shi, Jicong

2004-03-01

51

Accelerating and storing polarized hadron beams  

SciTech Connect

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

Teng, L.C.

1990-10-01

52

Beam parametr measurements for the SLAC linear collider  

SciTech Connect

A stable, closely-controlled, high-intensity, single-bunch beam will be required for the SLAC Linear Collider. The characteristics of short-pulse, low-intensity beams in the SLAC linac have been studied. A new, high-intensity thermionic gun, subharmonic buncher and S-band buncher/accelerator section were installed recently at SLAC. With these components, up to 10/sup 11/ electrons in a single S-band bunch are available for injection into the linac. the first 100-m accelerator sector has been modified to allow control of short-pulse beams by a model-driven computer program. Additional instrumentation, including a computerized energy analyzer and emittance monitor have been added at the end of the 100-m sector. The beam intensity, energy spectrum, emittance, charge distribution and the effect of wake fields in the first accelerator sector have been measured. The new source and beam control system are described and the most recent results of the beam parameter measurements are discussed.

Clendenin, J.E.; Blocker, C.; Breidenbach, M.

1981-01-01

53

FUTURE LEPTON COLLIDERS AND LASER ACCELERATION  

SciTech Connect

Future high energy colliders along with their physics potential, and relationship to new laser technology are discussed. Experimental approaches and requirements for New Physics exploration are also described.

PARSA,Z.

2000-05-30

54

SciDAC advances in beam dynamics simulation: from light sources to colliders  

SciTech Connect

In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of SciDAC-II accelerator project,"Community Petascale Project for Accelerator Science and Simulation (ComPASS)." Several parallel computational tools for beam dynamics simulation will be described. A number of applications in current and future accelerator facilities, e.g., LCLS, RHIC, Tevatron, LHC, ELIC, are presented.

Qiang, Ji; Qiang, J.; Borland, M.; Kabel, A.; Li, R.; Ryne, R.; Stern, E.; Wang, Y.; Wasserman, H.; Zhang, Y.

2008-06-16

55

Status and future directions for advanced accelerator research - conventional and non-conventional collider concepts  

SciTech Connect

The relationship between advanced accelerator research and future directions for particle physics is discussed. Comments are made about accelerator research trends in hadron colliders, muon colliders, and e{sup +}3{sup {minus}} linear colliders.

Siemann, R.H.

1997-01-01

56

Two-Beam Accelerator: structure studies and 35 GHz experiments  

SciTech Connect

The Two-Beam Accelerator (TBA) shows great promise for achieving high accelerating gradients, perhaps >250 MV/m, for such machines as electron linear colliders. This paper presents the results of studies of candidate structures for a TBA. Also, the hardware and program for 35 GHz high-gradient testing are described. 18 refs., 13 figs.

Hopkins, D.B.; Kuenning, R.W.

1985-05-01

57

Coherent Beam-Beam Interactions in Electron-Positron Colliders  

SciTech Connect

We present the results of a new calculational technique that evaluates the beam-beam force due to an arbitrary charge distribution. We find coherent instabilities that dominate at certain operating points and depend strongly on the degree of damping in the system. We conclude that while these resonances may play a significant role for colliders with low damping, with a careful choice of operating points they should present no danger to the new generation of high luminosity heavy-quark factories under design.

Krishnagopal, S.

1991-08-01

58

PIC Simulations of Colliding Pulse Injection for Laser Wakefield Acceleration  

Microsoft Academic Search

The use of colliding laser pulses to control the injection of plasma electrons into the plasma wake of a laser wakefield accelerator (LWFA) is a promising approach to obtaining GeV scale electron bunches with orders of magnitude smaller emittance and energy spread. Colliding pulse injection (CPI) is being explored experimentally by groups around the world. We will present recent particle-in-cell

David Bruhwiler; Ben Cowan; Kevin Paul; John Cary; Cameron Geddes; Estelle Cormier-Michelle; Eric Esarey; Carl Schroeder; Wim Leemans

2009-01-01

59

Excitation of Accelerating Plasma Waves by Counter-propagating Laser Beams  

SciTech Connect

Generation of accelerating plasma waves using two counter-propagating laser beams is considered. Colliding-beam accelerator requires two laser pulses: the long pump and the short timing beam. We emphasize the similarities and differences between the conventional laser wakefield accelerator and the colliding-beam accelerator (CBA). The highly nonlinear nature of the wake excitation is explained using both nonlinear optics and plasma physics concepts. Two regimes of CBA are considered: (i) the short-pulse regime, where the timing beam is shorter than the plasma period, and (ii) the parametric excitation regime, where the timing beam is longer than the plasma period. Possible future experiments are also outlined.

Gennady Shvets; Nathaniel J. Fisch; and Alexander Pukhov

2001-08-30

60

SciDAC Advances in Beam Dynamics Simulation: From Light Sources to Colliders  

SciTech Connect

In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of the SciDAC-2 accelerator project 'Community Petascale Project for Accelerator Science and Simulation (ComPASS).' Several parallel computational tools for beam dynamics simulation are described. Also presented are number of applications in current and future accelerator facilities (e.g., LCLS, RHIC, Tevatron, LHC, and ELIC). Particle accelerators are some of most important tools of scientific discovery. They are widely used in high-energy physics, nuclear physics, and other basic and applied sciences to study the interaction of elementary particles, to probe the internal structure of matter, and to generate high-brightness radiation for research in materials science, chemistry, biology, and other fields. Modern accelerators are complex and expensive devices that may be several kilometers long and may consist of thousands of beamline elements. An accelerator may transport trillions of charged particles that interact electromagnetically among themselves, that interact with fields produced by the accelerator components, and that interact with beam-induced fields. Large-scale beam dynamics simulations on massively parallel computers can help provide understanding of these complex physical phenomena, help minimize design cost, and help optimize machine operation. In this paper, we report on beam dynamics simulations in a variety of accelerators ranging from next generation light sources to high-energy ring colliders that have been studied during the first year of the SciDAC-2 accelerator project.

Qiang, J.; Borland, M.; /LBL, Berkeley; Kabel, A.; /Argonne; Li, R.; /Jefferson Lab; Ryne, R.; /LBL, Berkeley; Stern, E.; /Fermilab; Wang, Y.; /Argonne; Wasserman, H.; /LBL, Berkeley; Zhang, Y.; /SLAC

2011-11-14

61

Acceleration of polarized proton beams  

SciTech Connect

The acceleration of polarized beams in circular accelerators is complicated by the numerous depolarizing spin resonances. Using a partial Siberian snake and a rf dipole that ensure stable adiabatic spin motion during acceleration has made it possible to accelerate polarized protons to 25 GeV at the Brookhaven AGS. Full Siberian snakes are being developed for RHIC to make the acceleration of polarized protons to 250 GeV possible. A similar scheme is being studied for the 800 GeV HERA proton accelerator.

Roser, T.

1998-12-31

62

Laser triggered injection of electrons in a laser wakefield accelerator with the colliding pulse method  

SciTech Connect

An injection scheme for a laser wakefield accelerator that employs a counter propagating laser (colliding with the drive laser pulse, used to generate a plasma wake) is discussed. The threshold laser intensity for electron injection into the wakefield was analyzed using a heuristic model based on phase-space island overlap. Analysis shows that the injection can be performed using modest counter propagating laser intensity a{sub 1} < 0.5 for a drive laser intensity of a{sub 0} = 1.0. Preliminary experiments were preformed using a drive beam and colliding beam. Charge enhancement by the colliding pulse was observed. Increasing the signal-to-noise ratio by means of a preformed plasma channel is discussed.

Nakamura, K.; Fubiani, G.; Geddes, C.G.R.; Michel, P.; van Tilborg, J.; Toth, C.; Esarey, E.; Schroeder, C.B.; Leemans, W.P.

2004-10-22

63

Beam-induced energy deposition issues in the Very Large Hadron Collider  

SciTech Connect

Energy deposition issues are extremely important in the Very Large Hadron Collider (VLHC) with huge energy stored in its 20 TeV (Stage-1) and 87.5 TeV (Stage-2) beams. The status of the VLHC design on these topics, and possible solutions of the problems are discussed. Protective measures are determined based on the operational and accidental beam loss limits for the prompt radiation dose at the surface, residual radiation dose, ground water activation, accelerator components radiation damage and quench stability. The beam abort and beam collimation systems are designed to protect accelerator from accidental and operational beam losses, IP region quadrupoles from irradiation by the products of beam-beam collisions, and to reduce the accelerator-induced backgrounds in the detectors.

Nikolai V. Mokhov; Alexandr I. Drozhdin; G. William Foster

2001-06-26

64

Coherent instabilities in the booster and collider of the heavy ion accelerator complex NICA  

NASA Astrophysics Data System (ADS)

In the first part some knowledge about the coherent instabilities in cyclic accelerators and storage rings necessary for the analysis of the collective effects in the heavy ion collider NICA is given. The second part discusses the possibilities for arising of coherent instabilities in the booster and in the collider of the NICA complex. Both coupling impedances and instability thresholds and growth rates have been estimated for single and coupled bunches. Parameters of the beam feedback system for damping of the instabilities have been analyzed. The investigation has been performed at the Veksler and Baldin Laboratory of High Energy Physics, JINR.

Dinev, D.

2013-07-01

65

Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider  

SciTech Connect

To reach design luminosity, the International Linear Collider (ILC) must be able to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittances are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 37 nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.

Araki, S.; Hayano, H.; Higashi, Y.; Honda, Y.; Kanazawa, K.; Kubo, K.; Kume, T.; Kuriki, M.; Kuroda, S.; Masuzawa, M.; Naito, T.; Okugi, T.; Sugahara, R.; Takahashi, T.; Tauchi, T.; Terunuma, N.; Toge, N.; Urakawa, J.; Vogel, V.; Yamaoka, H.; Yokoya, K.; /KEK, Tsukuba /Beijing, Inst. High Energy Phys. /Novosibirsk, IYF /Daresbury /CERN /Hiroshima U. /Orsay, LAL /LLNL, Livermore /North Carolina A-T State U. /Oxford U. /Pohang Accelerator Lab. /Queen Mary, U. of London /Royal Holloway, U. of London /DESY /SLAC /University Coll. London /Oregon U. /Tokyo U.

2005-05-27

66

INTRA-BEAM SCATTERING SCALING FOR VERY LARGE HADRON COLLIDERS.  

SciTech Connect

For Very Large Hadron Colliders (VLHC), flat hadron beams [2] with their vertical emittance much smaller than their horizontal emittance are proposed to maximize the design luminosity. Emittance growth caused by intra-beam scattering (IBS) is a concern on the realization of such flat-beam conditions. Based on existing IBS formalism on beams of Gaussian distribution, we analytically derive [6] the IBS growth rate and determine the IBS limit on the aspect ratio for a flat beam.

WEI,J.; PARZEN,G.

2001-06-18

67

Tests of the FONT3 Linear Collider Intra-Train Beam Feedback System at the ATF  

SciTech Connect

We report preliminary results of beam tests of the FONT3 Linear Collider intra-train position feedback system prototype at the Accelerator Test Facility at KEK. The feedback system incorporates a novel beam position monitor (BPM) processor with a latency below 5 nanoseconds, and a kicker driver amplifier with similar low latency. The 56 nanosecond-long bunchtrain in the ATF extraction line was used to test the prototype BPM processor. The achieved latency will allow a demonstration of intra-train feedback on timescales relevant even for the CLIC Linear Collider design.

Burrows, P.N.; Christian, G.; Clarke, C.; Hartin, A.; Dabiri Khah, H.; Molloy, S.; White, G.R.; /Queen Mary, U. of London; Frisch, J.C.; Markiewicz, T.W.; McCormick, D.J.; Ross, M.C.; Smith, S.; Smith, T.J.; /SLAC; Kalinin, A.; /Daresbury; Perry, C.; /Oxford Instruments

2006-03-14

68

Precision measurements of the SLC (Stanford Linear Collider) beam energy  

SciTech Connect

A method of precisely determining the beam energy in high energy linear colliders has been developed using dipole spectrometers and synchrotron radiation detectors. Beam lines implementing this method have been installed on the Stanford Linear Collider. An absolute energy measurement with an accuracy of better than deltaE/E = 5 /times/ 10/sup /minus/4/ can be achieved on a pulse-to-pulse basis. The operation of this system will be described. 4 refs., 3 figs., 1 tab.

Kent, J.; King, M.; Von Zanthier, C.; Watson, S.; Levi, M.; Rouse, F.; Bambade, P.; Erickson, R.; Jung, C.K.; Nash, J.

1989-03-01

69

62-TeV center of mass hadron collider with superbunch beams  

SciTech Connect

The scheme of a 62-TeV center of mass p-p collider with superbunch beams at Fermilab is proposed as a practical and realistically achievable future project. It will be built in two stages, using the same tunnel, first with a 2 Tesla low field magnet collider ring and later with a 10 Tesla high field magnet collider ring. Both low and high field magnets have twin bore aperture and will be installed in the tunnel with the circumference of 87.25 km. In each bore a proton beam is accelerated, using induction cavities to increase luminosity. In the first stage they install a 7 TeV accelerator ring with operating field of 2 Tesla, based on the superferric transmission-line design. This ring will be operated at a 14-TeV center of mass collider. This will have the same energy as the LHC, but it will have 15 times higher luminosity, namely 1.5 x 10{sup 35}/cm{sup 2}/sec. The estimated synchrotron radiation is negligible with this machine. The existing Fermilab accelerator system, including the 150 GeV main injector, will be used as the injector system. Its rough cost estimation and schedule for this first stage are presented. In the second stage proton beams are accelerated, also using induction cavities up to 31 TeV with the 10 Tesla dipole magnets. The counter circulating beams will collide with the 62-TeV center of mass energy. With the superbunch beams they can expect the luminosity can be increased about 15 times more than the conventional method with RF cavities. It will be 10{sup 35}/cm{sup 2}/sec. In the second stage, the synchrotron radiation power will be about 12 W/m, and they need an elaborated beam screen.

Ryuji Yamada et al.

2001-11-05

70

Linac ring collider  

Microsoft Academic Search

The collision of a linear accelerator electron beam with a particle beam stored in a ring allows center of mass energies and luminosities beyond those achievable in pure storage ring colliders. The constraints of such a collider scheme and the unusual beam-beam interaction scenario with a highly disrupted electron beam are discussed. Machine parameters for a high luminosity B factory

P. Grosse Wiesmann

1991-01-01

71

Controlled laser plasma wakefield acceleration of electrons via colliding pulse injection in non-collinear geometry  

NASA Astrophysics Data System (ADS)

Colliding laser pulses [1] have been proposed as a method for controlling injection of electrons into a laser wakefield accelerator (LWFA) and hence producing high quality electron beams with energy spread below 1% and normalized emittances < 1 micron. The. One pulse excites a plasma wake, and a collinear pulse following behind it collides with a counterpropagating pulse forming a beat pattern that boosts background electrons into accelerating phase. A variation of the original method uses only two laser pulses [2] which may be non-collinear. The first pulse drives the wake, and beating of the trailing edge of this pulse with the colliding pulse injects electrons. Non-collinear injection avoids optical elements on the electron beam path (avoiding emittance growth). We report on progress of non-collinear experiments at LBNL, using the Ti:Sapphire laser at the LOASIS facility of LBNL. New results indicate that the electron beam properties are affected by the presence of the second beam. [1] E. Esarey, et al, Phys. Rev. Lett 79, 2682 (1997) [2] G. Fubiani, Phys. Rev. E 70, 016402 (2004)

Toth, Csaba; Nakamura, Kei; Geddes, Cameron; Panasenko, Dmitriy; Plateau, Guillaume; Matlis, Nicholas; Schroeder, Carl; Esarey, Eric; Leemans, Wim

2007-11-01

72

Linear accelerators for TeV colliders. Revision  

SciTech Connect

The basic scaling relations for important linear collider design parameters are introduced. Some of the basic concepts concerning the design of accelerating structures are presented, and breakdown limitations are discussed. Rf power sources are considered. Some of the key concepts of wakefield accelerators are discussed, and some examples of wake fields for typical linac structures are presented. Some general concepts concerning emittance, and the limitations on the emittance that can be obtained from linac guns and damping rings are discussed. 49 refs., 15 figs. (LEW)

Wilson, P.B.

1985-10-01

73

Electron injection and acceleration by colliding laser pulses in plasmas  

SciTech Connect

An injector and accelerator is analyzed that uses three collinear laser pulses in a plasma an intense pump pulse, which generates a large wakefield ({>=}15 GV/m), and two counterpropagating injection pulses. When the injection pulses collide, a slow phase velocity ponderomotive wave is generated that injects electrons into the fast wakefield for acceleration. For injection pulse intensities of 5x10{sup 16} W/cm{sup 2} and wakefield amplitudes of {delta}n/n{approx_equal}0.6, the production of ultrashort ({<=}20 fs) relativistic electron bunches with energy spreads {<=}20% and densities {>=}10{sup 17} cm{sup -3} appears possible.

Esarey, E.; Hubbard, R. F.; Ting, A.; Sprangle, P.; Leemans, W. P. [Beam Physics Branch, Plasma Physics Division Naval Research Laboratory, Washington District of Columbia 20375-5346 (United States); Ernest Orlando Lawrence Berkeley National Laboratory, University of California at Berkeley, Berkeley California 94720 (United States)

1997-04-15

74

Design and Interpretation of Colliding Pulse Injected Laser-Plasma Acceleration Experiments  

NASA Astrophysics Data System (ADS)

The use of colliding laser pulses to control the injection of plasma electrons into the plasma wake of a laser-plasma accelerator is a promising approach to obtaining GeV scale electron bunches with reduced emittance and energy spread. Colliding Pulse Injection (CPI) experiments are being performed by groups around the world. We present recent particle-in-cell simulations, using the parallel VORPAL framework, of CPI for physical parameters relevant to ongoing experiments of the LOASIS program at LBNL. We perform parameter scans in order to optimize the quality of the bunch, and compare the results with experimental data. Effect of non-ideal gaussian pulses and laser self-focusing in the plasma channel on the trapped bunch are evaluated. For optimized parameters accessible in the experiment, a 20 pC electron beam can be accelerated to 300 MeV with percent level energy spread.

Cormier-Michel, Estelle; Ranjbar, Vahid H.; Bruhwiler, David L.; Chen, Min; Geddes, Cameron G. R.; Esarey, Eric; Schroeder, Carl B.; Leemans, Wim P.

2010-11-01

75

Design and Interpretation of Colliding Pulse Injected Laser-Plasma Acceleration Experiments  

SciTech Connect

The use of colliding laser pulses to control the injection of plasma electrons into the plasma wake of a laser-plasma accelerator is a promising approach to obtaining GeV scale electron bunches with reduced emittance and energy spread. Colliding Pulse Injection (CPI) experiments are being performed by groups around the world. We present recent particle-in-cell simulations, using the parallel VORPAL framework, of CPI for physical parameters relevant to ongoing experiments of the LOASIS program at LBNL. We perform parameter scans in order to optimize the quality of the bunch, and compare the results with experimental data. Effect of non-ideal gaussian pulses and laser self-focusing in the plasma channel on the trapped bunch are evaluated. For optimized parameters accessible in the experiment, a 20 pC electron beam can be accelerated to 300 MeV with percent level energy spread.

Cormier-Michel, Estelle; Ranjbar, Vahid H.; Bruhwiler, David L. [Tech-X Corporation, 5621 Arapahoe Ave, Suite A, Boulder, CO 80303 (United States); Chen, Min; Geddes, Cameron G. R.; Esarey, Eric; Schroeder, Carl B.; Leemans, Wim P. [LOASIS program, Lawrence Berkeley National Laboratory, 1 cyclotron road, Berkeley, CA 94720 (United States)

2010-11-04

76

Approaches to Beam Stabilization in X-Band Linear Colliders  

Microsoft Academic Search

In order to stabilize the beams at the interaction point, the X-band linear collider proposes to use a combination of techniques: inter-train and intra-train beam-beam feedback, passive vibration isolation, and active vibration stabilization based on either accelerometers or laser interferometers. These systems operate in a technologically redundant fashion: simulations indicate that if one technique proves unusable in the final machine,

Josef Frisch; Linda Hendrickson; Thomas Himel; Thomas Markiewicz; Tor Raubenheimer; Andrei Seryi; Philip Burrows; Stephen Molloy; Glen White

2006-01-01

77

Acceleration of exp 14 C BEAMS in Electrostatic Accelerators.  

National Technical Information Service (NTIS)

Operational problems in the production and acceleration of exp 14 C beams for nuclear structure research in Los Alamos National Laboratory's Van de Graaff accelerators are discussed. Methods for the control of contamination in ion sources, accelerators an...

L. J. Rowton J. R. Tesmer

1981-01-01

78

Studies of beam dynamics in relativistic klystron two-beam accelerators.  

National Technical Information Service (NTIS)

Two-beam accelerators (TBAs) based upon free-electron lasers (FELs) or relativistic klystrons (RK-TBAs) have been proposed as efficient power sources for next generation high-energy linear colliders. Studies have demonstrated the possibility of building T...

S. M. Lidia

1999-01-01

79

International X-Band Linear Collider Accelerator Structure R&D  

SciTech Connect

For more than fifteen years before the International Technology Recommendation Panel (ITRP) decision in August, 2004, there were intensive R&D activities and broad international collaboration among the groups at SLAC, KEK, FNAL, LLNL and other labs for the room temperature X-Band accelerator structures. The goal was to provide an optimized design of the main linac structure for the NLC (Next Linear Collider) or GLC (Global Linear Collider). There have been two major challenges in developing X-band accelerator structures for the linear colliders. The first is to demonstrate stable, long-term operation at the high gradient (65 MV/m) that is required to optimize the machine cost. The second is to strongly suppress the beam induced long-range wakefields, which is required to achieve high luminosity. More than thirty X-band accelerator structures with various RF parameters, cavity shapes and coupler types have been fabricated and tested since 1989. A summary of the main achievements and experiences are presented in this talk including the structure design, manufacturing techniques, high power performance, and other structure related issues. Also, the new progress in collaborating with the CLIC, high gradient structures and X-Band structure applications for RF deflectors and others are briefly introduced.

Wang, J.W.; /SLAC

2009-03-04

80

Extensions of MAD Version 8 to Include Beam Acceleration  

SciTech Connect

In this paper, the authors describe modifications to MAD version 8.23 to include linear accelerator cavities and beam acceleration. An additional energy variable has been added which is modified as the beam passes through LCAV elements (linear accelerator cavities) and can be used as a constraint in matching commands. The calculation of the beta functions and phase advance is consistent with that in other codes that treat acceleration such as TRANSPORT or DIMAD. These modifications allow this version of MAD to be used for the design and modeling of linacs and the authors present examples from the Next Linear Collider design as well as a muon acceleration complex. The code is available from CERN or SLAC.

Raubenheimer, Tor O

2000-07-20

81

Pair production as a probe of colliding beam size  

SciTech Connect

We propose the use of soft e{sup +}e{sup {minus}} pairs as a non-evasive measurement of the colliding beam size. The angular distribution of the pair particles that have different sign of charge from that of the opposing beam, provides the information about the aspect ratio of the beam. The transverse momentum of the other species in the pair, on the other hand, carries information about the horizontal dimension of the beam. Together, one can in principle measure both {sigma}{sub x} and {sigma}{sub y}.

Chen, Pisin; Irwin, J.; Spitkovsky, A.

1994-07-01

82

Effect of Beam-Beam Interactions on Stability of Coherent Oscillations in a Muon Collider  

SciTech Connect

In order to achieve peak luminosity of a muon collider in the 10{sup 34}/cm{sup 2}/s range the number of muons per bunch should be of the order of a few units of 10{sup 12} rendering the beam-beam parameter as high as 0.1 per IP. Such strong beam-beam interaction can be a source of instability if the working point is chosen close to a coherent beam-beam resonance. On the other hand, the beam-beam tunespread can provide a mechanism of suppression of the beam-wall driven instabilities. In this report the coherent instabilities driven by beam-beam and beam-wall interactions are studied with the help of BBSS code for the case of 1.5 TeV c.o.m muon collider.

Alexahin, Y.; /Fermilab; Ohmi, K.; /KEK, Tsukuba

2012-05-01

83

Electron Injection into Laser Wakefields by the Two-Beam Colliding Pulse Scheme  

NASA Astrophysics Data System (ADS)

Laser driven acceleration in plasmas has succeeded in producing electron beams containing considerable amount of charge (> 100 pC) at energies in excess of 100 MeV. Control of the trapping process is needed to generate monoenergetic electron beams in a reproducible manner. We report on experimental progress of laser triggered injection of electrons into laser wakefields with a two-pulse colliding laser scheme[1]. The experiments use the multi-beam, multi-terawatt Ti:Al_2O3 laser at the l'OASIS facility of LBNL. In the experiments, two counter propagating beams 30^rc angle are focused onto a high density ( ˜10^19/cm^3) gas jet. Preliminary results indicate that electron beam properties are affected by the second beam. Details of the experiments will be shown as well as comparisons with simulations. [1] G. Fubiani, et., al, Phys. Rev. E 70, 016402 (2004).

Nakamura, K.; Michel, P.; Toth, C. S.; Geddes, C. G. R.; van Tilborg, J.; Fubiani, G.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.; Cary, J. R.; Giacone, R.; Bruhwiler, D.

2004-11-01

84

Colliding-beams polarized ion source  

SciTech Connect

This ion source was to be purchased from ANAC, Inc., a New Zealand-based supplier of beam optics hardware and atomic beam polarized ion sources in December 1982. Shortly before scheduled delivery ANAC went into receivership. During 1983 little work was done on the project as various steps were taken by us, first to get the ion source completed at ANAC, and then, failing that, to obtain the existing parts. In early 1984 we began work to finish the ion source in Seattle. The project is nearly complete, and this article presents progress to date. 2 refs.

Trainor, T.A.; Douglas, J.G.; Badt, D.; Christiensen, C.; Herron, A.; Leach, D.; Olsen, J.; Osborne, J.L.; Zeps, V.

1985-01-01

85

Beam-beam simulation code BBSIM for particle accelerators  

NASA Astrophysics Data System (ADS)

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

Kim, H. J.; Sen, T.

2011-06-01

86

Beam-beam simulation code BBSIM for particle accelerators  

SciTech Connect

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

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

2011-01-01

87

Scraping beam halo in {mu} {sup +} {mu} {sup minus} colliders  

SciTech Connect

Beam halo scraping schemes have been explored in the 50 x 50 GeV and 2 x 2 TeV {mu}{sup +}{mu}{sup -} colliders using both absorbers and electrostatic deflectors. Utility sections have been specially designed into the rings for scraping. Results of realistic STRUCT- MARS Monte-Carlo simulations show that for the low-energy machine a scheme with a 5 m long steel absorber suppresses losses in the interaction region by three orders of magnitude. The same scraping efficiency at 2 TeV is achieved only by complete extraction of beam halo from the machine. The effect of beam-induced power dissipation in the collider superconducting magnets and detector backgrounds is shown both for the first few turns after injection and for the rest of the cycle.

Drozhdin, A.; Mokhov, N.; Johnstone, C.; Wan, W.; Garren, A.

1998-01-01

88

Approaches to Beam Stabilization in X-Band Linear Colliders  

SciTech Connect

In order to stabilize the beams at the interaction point, the X-band linear collider proposes to use a combination of techniques: inter-train and intra-train beam-beam feedback, passive vibration isolation, and active vibration stabilization based on either accelerometers or laser interferometers. These systems operate in a technologically redundant fashion: simulations indicate that if one technique proves unusable in the final machine, the others will still support adequate luminosity. Experiments underway for all of these technologies have already demonstrated adequate performance.

Frisch, Josef; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Raubenheimer, Tor; Seryi, Andrei; /SLAC; Burrow, Philip; Molloy, Stephen; White, Glen; /Queen Mary U. of London

2006-09-05

89

Beam-beam luminosity limitation in electron-positron colliding rings  

SciTech Connect

To account for observed luminosity limitations in electron-positron colliding rings we identify parametric pumping of vertical betatron oscillations by horizontal oscillations as the leading effect, solve the nonlinear single-particle equation exactly, obtain the strong-beam--strong-beam equilibrium by numerical simulation, calculate the luminosity, and identify regions of bad beam lifetime.

Peggs, S.; Talman, R.

1981-11-01

90

Accelerating light beams along arbitrary convex trajectories.  

PubMed

We demonstrate, theoretically and experimentally, nonbroadening optical beams propagating along any arbitrarily chosen convex trajectory in space. We present a general method to construct such beams, and demonstrate it by generating beams following polynomial and exponential trajectories. We find that all such beams, accelerating along any convex trajectory, display the same universal intensity cross section, irrespective of their acceleration. The universal features of these beams are explored using catastrophe theory. PMID:21699298

Greenfield, Elad; Segev, Mordechai; Walasik, Wiktor; Raz, Oren

2011-05-27

91

Obtaining slow beam spills at the SSC collider  

SciTech Connect

There is substantial interest in providing slow-spill external proton beams in parallel with ``interaction running`` at the 20 TeV SSC collider. The proposal is to cause a flux of particles to impinge on a target consisting of a bent crystal extraction channel. Additionally, a slow spill onto a conventional internal target could be used as a source of secondary beams for physics or test purposes and might also be used for B-physics as proposed for HERA. The ``natural`` beam loss rates from elastic and diffractive beam gas scattering and IP collisions are not sufficient to provide suitably intense external proton beams. To prevent loss of luminosity, the rf excitation is non-linear and preferentially blows up the halo of the beam. The ``target`` is to be located at a region of high dispersion forcing particles at the edge of the momentum space onto the target. T. Lohse in this workshop has described a proposed internal target to be used at HERA that will not employ rf excitation but will use the finite loss rates observed at the HERA machine. The Hera losses are caused by a variety of sources in addition to beam gas scattering or IP interactions. Initially, the beam lifetime at HERA was too short to obtain satisfactory integrated luminosities. Subsequently, through careful attention to detail, the beam lifetime was increased to > 20 hours. Even with these changes, present loss rates provide the required intensity onto an internal target. The Tevatron and SPS proton anti-proton colliders have had similar experiences with their investigations of loss rates and also find that beam lifetimes may be substantially shorter than expected solely from beam gas and IP interactions. This paper proposes deliberately introducing controlled errors li

Ritson, D.

1993-08-01

92

Colliding pulse injection experiments in non-collinear geometry for controlled laser plasma wakefield acceleration of electrons  

NASA Astrophysics Data System (ADS)

A method for controlled injection of electrons into a plasma wakefield relying on colliding laser pulses [1] has been proposed a decade ago to produce high quality relativistic electron beams with energy spread below 1% and normalized emittances < 1 micron from a laser wakefield accelerator (LWFA). The original idea uses three pulses in which one pulse excites the plasma wake and a trailing laser pulse collides with a counterpropagating one to form a beat pattern that boosts background electrons to catch the plasma wave. Another, two-beam off-axis injection method [2] with crossing angles varying from 180 to 90 degrees avoids having optical elements on the path of the electron beam and has been studied at the LOASIS facility of LBNL as a viable method for laser triggered injection. It allows low dark current operation with controllable final beam energy and low energy spread. Here, we report on progress of electron optical injection via the two-beam non-collinear colliding pulse scheme using multi-terawatt Ti:Sapphire laser beams (45 fs, 100s of mJ) focused onto a Hydrogen gas plume. Experimental results indicate that electron beam properties are affected by the second beam. *This work is supported by DoE under contract DE-AC02-05CH11231. [1] E. Esarey, et al, Phys. Rev. Lett 79, 2682 (1997) [2] G. Fubiani, Phys. Rev. E 70, 016402 (2004)

Toth, Csaba; Nakamura, K.; Geddes, C.; Michel, P.; Schroeder, C.; Esarey, E.; Leemans, W.

2006-10-01

93

Colliding beams: what is an appropriate mathematical approach  

SciTech Connect

The success of notions of self-similarity in the analysis of certain one-dimensional iterative systems related to turbulent flow encourages us to seek applications of such notions to the analysis of the higher-dimensional conservative systems corresponding to colliding-beam storage rings. This may yield information inaccessible to the resonance-overlap criterion, and may be of greater relevance to observed phenomena.

Schonfeld, J.F.

1981-01-01

94

Interplay of space-charge and beam-beam effects in a collider  

SciTech Connect

Operation of a collider at low energy or use of cooling techniques to increase beam density may result in luminosity limitation due to the space-charge effects. Understanding of such limitation became important for Low-Energy RHIC physics program with heavy ions at the center of mass energies of 5-20 GeV/nucleon. For a collider, we are interested in a long beam lifetime, which limits the allowable space-charge tune shift. An additional complication comes from the fact that ion beams are colliding, which requires careful consideration of the interplay of direct space-charge and beam-beam effects. This paper summarizes the initial observations during experimental studies in RHIC at low energies.

Fedotov, A.V.; Blaskiewicz, M.; Fischer, W.; Satogata, T.; Tepikian, S.

2010-09-27

95

Colliding pulse injection experiments in non-collinear geometryfor controlled laser plasma wakefield acceleration of electrons  

SciTech Connect

An optical injection scheme for a laser-plasma basedaccelerator which employs a non-collinear counter-propagating laser beamto push background electrons in the focusing and acceleration phase viaponderomotive beat with the trailing part of the wakefield driver pulseis discussed. Preliminary experiments were performed using a drive beamof a_0 = 2.6 and colliding beam of a_1 = 0.8 both focused on the middleof a 200 mu m slit jet backed with 20 bar, which provided ~; 260 mu mlong gas plume. The enhancement in the total charge by the collidingpulse was observed with sharp dependence on the delay time of thecolliding beam. Enhancement of the neutron yield was also measured, whichsuggests a generation of electrons above 10 MeV.

Toth, Carl B.; Esarey, Eric H.; Geddes, Cameron G.R.; Leemans,Wim P.; Nakamura, Kei; Panasenko, Dmitriy; Schroeder, Carl B.; Bruhwiler,D.; Cary, J.R.

2007-06-25

96

Renormalization theory of beam-beam interaction in electron-positron colliders  

SciTech Connect

This note is devoted to explaining the essence of the renormalization theory of beam-beam interaction for carrying out analytical calculations of equilibrium particle distributions in electron-positron colliding beam storage rings. Some new numerical examples are presented such as for betatron tune dependence of the rms beam size. The theory shows reasonably good agreements with the results of computer simulations. 5 refs., 6 figs.

Chin, Y.H.

1989-07-01

97

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOEpatents

An electron beam accelerator comprising an electron beam generator-injector to produce a focused beam of .gtoreq.0.1 MeV energy electrons; a plurality of substantially identical, aligned accelerator modules to sequentially receive and increase the kinetic energies of the beam electrons by about 0.1-1 MeV per module. Each accelerator module includes a pulse-forming network that delivers a voltage pulse to the module of substantially 0.1-1 MeV maximum energy over a time duration of .ltoreq.1 .mu.sec.

Birx, Daniel L. (Brentwood, CA); Reginato, Louis L. (Orinda, CA)

1987-01-01

98

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOEpatents

An electron beam accelerator comprising an electron beam generator-injector to produce a focused beam of .gtoreq.0.1 MeV energy electrons; a plurality of substantially identical, aligned accelerator modules to sequentially receive and increase the kinetic energies of the beam electrons by about 0.1-1 MeV per module. Each accelerator module includes a pulse-forming network that delivers a voltage pulse to the module of substantially .gtoreq.0.1-1 MeV maximum energy over a time duration of .ltoreq.1 .mu.sec.

Birx, Daniel L. (Brentwood, CA); Reginato, Louis L. (Orinda, CA)

1988-01-01

99

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOEpatents

An electron beam accelerator is described comprising an electron beam generator-injector to produce a focused beam of greater than or equal to .1 MeV energy electrons; a plurality of substantially identical, aligned accelerator modules to sequentially receive and increase the kinetic energies of the beam electron by about .1-1 MeV per module. Each accelerator module includes a pulse-forming network that delivers a voltage pulse to the module of substantially .1-1 MeV maximum energy over a time duration of less than or equal to 1 ..mu..sec.

Birx, D.L.; Reginato, L.L.

1984-03-22

100

Negative ion beam acceleration and transport experiments  

NASA Astrophysics Data System (ADS)

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

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

1985-11-01

101

Optical beam profile monitor and residual gas fluorescence at the relativistic heavy ion collider polarized hydrogen jet.  

PubMed

A gas fluorescence beam profile monitor has been implemented at the relativistic heavy ion collider (RHIC) using the polarized atomic hydrogen gas jet, which is part of the polarized proton polarimeter. RHIC proton beam profiles in the vertical plane of the accelerator are obtained as well as measurements of the width of the gas jet in the beam direction. For gold ion beams, the fluorescence cross section is sufficiently large so that profiles can be obtained from the residual gas alone, albeit with long light integration times. We estimate the fluorescence cross sections that were not known in this ultrarelativistic regime and calculate the beam emittance to provide an independent measurement of the RHIC beam. This optical beam diagnostic technique, utilizing the beam induced fluorescence from injected or residual gas, offers a noninvasive particle beam characterization and provides visual observation of proton and heavy ion beams. PMID:19044742

Tsang, T; Bellavia, S; Connolly, R; Gassner, D; Makdisi, Y; Russo, T; Thieberger, P; Trbojevic, D; Zelenski, A

2008-10-01

102

1 ms Pulse Beam Generation and Acceleration by Photocathode Radio Frequency Gun and Superconducting Accelerator  

NASA Astrophysics Data System (ADS)

We report the successful generation and acceleration of a 1-ms-long pulse and multibunch electron beam by a normal conducting photocathode RF gun and a super conducting accelerator at the KEK Superconducting Test Facility (STF). A 1.3 GHz normal conducting RF gun generates a 1 ms and 10 mA macropulse that fully satisfies the designed parameters. This is the longest macropulse generated by a normal conducting RF gun with a frequency of more than 1 GHz. A beam acceleration of up to 40 MeV was demonstrated with more than 60% of the designed average current. The accelerated beam properties were evaluated: the intensity and energy fluctuations were 3.8% and less than 0.08%, respectively. These beam properties are sufficient for the requirement of the STF operation including that in the quantum beam project, which is high-brightness-X-ray generation by inverse laser Compton scattering. The intensity fluctuation should be improved toward the International Linear Collider (ILC) for uniform acceleration.

Kuriki, Masao; Iijima, Hokuto; Hosoda, Seiichi; Watanabe, Ken; Hayano, Hitoshi; Urakawa, Junji; Isoyama, Goro; Kato, Ryukou; Kawase, Keigo; Kuramoto, Ayaka; Kashiwagi, Shigeru; Sakaue, Kazuyuki

2013-05-01

103

Beam-beam effects of gear changing in ring-ring colliders  

NASA Astrophysics Data System (ADS)

In ring-ring colliders, the collision frequency determines the bunch structures, e.g., the time between the bunches in both rings should be identical. Because of relatively low relativistic speed of the hadron beam in sub-TeV hadron-hadron- and electron-ions colliders, scanning the hadron beam's energy would require either a change in the circumference of one of the rings, or a switching of the bunch (harmonic) number in a ring. The later would cause so-called gear changing, i.e., the change of the colliding bunches turn by turn. In this article, we study the difficulties in beam dynamics in this gear-changing scheme.

Hao, Yue; Litvinenko, V. N.; Ptitsyn, V.

2014-04-01

104

Demonstration of two-beam acceleration and 30 GHz power production in the CLIC Test Facility  

NASA Astrophysics Data System (ADS)

The Compact Linear Collider (CLIC) Test Facility (CTF II) at CERN has recently demonstrated Two-Beam power production and acceleration at 30 GHz. With 41 MW of 30 GHz power produced in 14 ns pulses at a repetition rate of 5 Hz, the main beam has been accelerated by 28 MeV. The 30 GHz RF power is extracted in low impedance decelerating structures from a low-energy, high-current ``drive beam'' which runs parallel to the main beam. The average current in the drive-beam train is 25 A, while the peak current exceeds 2 kA. Crosschecks between measured drive-beam charge, 30 GHz power and main-beam energy gain are in good agreement. In this paper, some relevant experimental and technical issues on drive-beam generation, two-beam power production and acceleration are presented.

Bossart, R.; Braun, H. H.; Carron, G.; Chanudet, M.; Chautard, F.; Delahaye, J. P.; Godot, J. C.; Hutchins, S.; Martinez, C.; Suberlucq, G.; Tenenbaum, P.; Thorndahl, L.; Trautner, H.; Valentini, M.; Wilson, I.; Wuensch, W.

1999-05-01

105

Research and Development of Future Muon Collider  

SciTech Connect

Muon collider is a considerable candidate of the next generation high-energy lepton collider machine. A novel accelerator technology must be developed to overcome several intrinsic issues of muon acceleration. Recent research and development of critical beam elements for a muon accelerator, especially muon beam phase space ionization cooling channel, are reviewed in this paper.

Yonehara, K.; /Fermilab

2012-05-01

106

Magnetic fusion with high energy self-colliding ion beams  

SciTech Connect

Field-reversed configurations of energetic large orbit ions with neutralizing electrons have been proposed as the basis of a fusion reactor. Vlasov equilibria consisting of a ring or an annulus have been investigated. A stability analysis has been carried out for a long thin layer of energetic ions in a low density background plasma. There is a growing body of experimental evidence from tokamaks that energetic ions slow down and diffuse in accordance with classical theory in the presence of large non-thermal fluctuations and anomalous transport of low energy (10 keV) ions. Provided that major instabilities are under control, it seems likely that the design of a reactor featuring energetic self-colliding ion beams can be based on classical theory. In this case a confinement system that is much better than a tokamak is possible. Several methods are described for creating field reversed configurations with intense neutralized ion beams.

Rostoker, N.; Wessel, F. (California Univ., Irvine, CA (United States)); Maglich, B. (Advanced Physics Corp., Irvine, CA (United States)); Fisher, A. (Naval Research Lab., Washington, DC (United States))

1992-06-01

107

Review of linear collider beam-beam interaction  

SciTech Connect

Three major effects from the interaction of e/sup +/e/sup /minus// beams---disruption, beamstrahlung, and electron-positron pair creation---are reviewed. For the disruption effects we discuss the luminosity enhancement factor, the maximum and rms disruption angles, and the ''kink instability''. All the results are obtained from computer simulations. Scaling laws for the numerical results and theoretical explanations of the computer acquired phenomena are offered wherever possible. For the beamstrahlung effects we concentrate only on the final electron energy spectrum resulting from multiple photon radiation process, and the deflection angle associated with low energy particles. For the effects from electron-positron pair creation, both coherent and incoherent processes of beamstrahlung pair creation are discussed. In addition to the estimation on total number of such pairs, we also look into the energy spectrum and the deflection angle. 17 refs., 23 figs., 1 tab.

Chen, P.

1989-01-01

108

Low-Level RF Signal Processing for the Next Linear Collider Test Accelerator  

NASA Astrophysics Data System (ADS)

In the X-band accelerator system for the Next Linear Collider Test Accelerator (NLCTA), the Low Level RF (LLRF) drive system must be very phase stable, but concurrently, be very phase agile. Phase agility is needed to make SLED power multiplier systems work and to shape the rf waveform to compensate beam loading in the accelerator sections. Similarly, precision fast phase and amplitude monitors are required to view, track, and feed back on rf signals at various locations throughout the system. The LLRF System is composed of several subsystems: the RF Reference System generates and distributes a reference 11.424 GHz rf signal to four rf stations, the Signal Processing Chassis creates the rf waveforms with the appropriate phase modulation, and the Phase Detector Assembly measures the amplitude and phase of monitored rf signals. The LLRF is run via VXI instrumentation. These instruments are controlled using HP VEE graphical programming software. Programs have been developed to shape the rf waveform, calibrate the phase modulators and demodulators, and display the measured waveforms. This paper describes these and other components of the LLRF system.

Holmes, Sharon; Adolphsen, Chris; Akre, Ron; Gold, Saul; Koontz, Ron; Nantista, Chris; Wilson, Zane; Ziomek, Chris

1997-05-01

109

Low-level RF signal processing for the Next Linear Collider Test Accelerator  

SciTech Connect

In the X-band accelerator system for the Next Linear Collider Test Accelerator (NLCTA), the Low Level RF (LLRF) drive system must be very phase stable, but concurrently, be very phase agile. Phase agility is needed to make the Stanford Linear Doubler (SLED) power multiplier systems Energy work and to shape the RF waveforms to compensate beam loading in the accelerator sections. Similarly, precision fast phase and amplitude monitors are required to view, track, and feed back on RF signals at various locations throughout the system. The LLRF is composed of several subsystems: the RF Reference System generates and distributes a reference 11.424 GHz signal to all of the RF stations, the Signal Processing Chassis creates the RF waveforms with the appropriate phase modulation, and the Phase Detector Assembly measures the amplitude and phase of monitor3ed RF signals. The LLRF is run via VXI instrumentation. These instruments are controlled using HP VEE graphical programming software. Programs have been developed to shape the RF waveform, calibrate the phase modulators and demodulators, and display the measured waveforms. This paper describes these and other components of the LLRF system.

Holmes, S.; Ziomek, C.; Adolphsen, C. [and others

1997-05-12

110

Beam-intensity limitations in linear accelerators  

SciTech Connect

Recent demand for high-intensity beams of various particles has renewed interest in the investigation of beam current and beam quality limits in linear RF and induction accelerators and beam-transport channels. Previous theoretical work is reviewed, and new work on beam matching and stability is outlined. There is a real need for extending the theory to handle the time evolution of beam emittance; some present work toward this goal is described. The role of physical constraints in channel intensity limitation is emphasized. Work on optimizing channel performance, particularly at low particle velocities, has resulted in major technological advances. The opportunities for combining such channels into arrays are discussed. 50 references.

Jameson, R.A.

1981-01-01

111

A nonlinear particle dynamics map of wakefield acceleration in a linear collider  

SciTech Connect

The performance of a wakefield accelerator in a high energy collider application is analyzed. In order to carry out this task, it is necessary to construct a strawman design system (no matter how preliminary) and build a code of the systems approach. A nonlinear dynamics map built on a simple theoretical model of the wakefield generated by the laser pulse (or whatever other method) is obtained and they employ this as a base for building a system with multi-stages (and components) as a high energy collider. The crucial figures of merit for such a system other than the final energy include the emittance (that determines the luminosity). The more complex the system is, the more opportunities the system has to degrade the emittance (or entropy of the beam). Thus the map gu ides one to identify where the crucial elements lie that affect the emittance. They find that a strong focusing force of the wakefield coupled with a possible jitter of the axis (or laser aiming) of each stage and a spread in the betatron frequencies arising from different phase space positions for individual particles leads to a phase space mixing. This sensitively controls the emittance degradation. They show that in the case of a uniform plasma the effect of emittance growth is large and may cause serious problems. They discuss possibilities to avoid it and control the situation.

Tajima, T.; Cheshkov, S.; Horton, W. [Univ. of Texas, Austin, TX (United States); Yokoya, K. [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

1998-08-01

112

High Quality Electron Beams from Laser Accelerators  

NASA Astrophysics Data System (ADS)

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

Leemans, Wim

2005-04-01

113

Pointing of laser-accelerated proton beams  

SciTech Connect

Small fluctuations in the acceleration sheath change the pointing of a proton beam accelerated from the rear side of a laser irradiated thin aluminum foil. The proton acceleration was produced with 40 fs pulses of a Ti:sapphire laser at an intensity of approximately 10{sup 19} W/cm{sup 2}. This observation has been made with a high spatial resolution Thomson spectrometer. The proton beam pointing has appeared stable in the energy range between the high energy cutoff (3 MeV) and 50% of this value. Deviations of the beam position at lower energies changes in a range of 0-3 mrad. The recorded pictures show wiggled and continuous proton traces which imply a release of the proton beam from the acceleration zone with a velocity chirp.

Schreiber, J.; Ter-Avetisyan, S.; Risse, E.; Kalachnikov, M.P.; Nickles, P.V.; Sandner, W.; Schramm, U.; Habs, D.; Witte, J.; Schnuerer, M. [MPI fuer Quantenoptik, Hans-Kopfermann-Str. 1, D 85748 Garching (Germany) and LMU Muenchen, Am Coulombwall 1, D 85748, Garching (Germany); Max Born Institut, Max Born Strasse 2a, D 12489 Berlin (Germany); Max Born Institut, Max Born Strasse 2a, D 12489 Berlin (Germany) and TU Berlin, Strasse des 17. Juni 135, D 10623 Berlin (Germany); LMU Muenchen, Am Coulombwall 1, D 85748, Garching (Germany); MPI fuer Quantenoptik, Hans-Kopfermann-Str. 1, D 85748 Garching (Germany); Max Born Institut, Max Born Strasse 2a, D 12489 Berlin (Germany)

2006-03-15

114

Beam Coupling to Optical Scale Accelerating Structures  

SciTech Connect

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

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

2007-03-27

115

Negative ion beam formation, transport and acceleration  

SciTech Connect

The BNL Neutral Beam Development Group is working on the development of negative ion based neutral beam systems, using high current density surface plasma sources of the magnetron and hollow cathode discharge (HCD) type. With the magnetron source, the plan is to transport a 2A D/sup -/ beam through a bending magnet before acceleration to 200 keV. In experiments with a pulsed magnetron, 0.4A of H/sup -/ was transported through a 90/sup 0/, n = 1, bending magnet with 80% transmission. With the lower operating pressure in the HCD source, close coupled acceleration will be applied. The MEQALAC, RFQ, and a dc accelerating scheme with periodic quadrupole focusing are considered for reaching higher energies. A preliminary experiment was performed with quadrupole beam transport and a 3.8 mA beam was transported through a series of twelve quadrupoles, with 3 mm apertures and a total length of 7.2 cm.

Alessi, J.G.

1981-01-01

116

Microwave accelerator E-beam pumped laser  

DOEpatents

A device and method for pumping gaseous lasers by means of a microwave accelerator. The microwave accelerator produces a relativistic electron beam which is applied along the longitudinal axis of the laser through an electron beam window. The incident points of the electron beam on the electron beam window are varied by deflection coils to enhance the cooling characteristics of the foil. A thyratron is used to reliably modulate the microwave accelerator to produce electron beam pulses which excite the laser medium to produce laser pulse repetition frequencies not previously obtainable. An aerodynamic window is also disclosed which eliminates foil heating problems, as well as a magnetic bottle for reducing laser cavity length and pressures while maintaining efficient energy deposition.

Brau, Charles A. (Los Alamos, NM) [Los Alamos, NM; Stein, William E. (Los Alamos, NM) [Los Alamos, NM; Rockwood, Stephen D. (Los Alamos, NM) [Los Alamos, NM

1980-01-01

117

RF beam control system for the Brookhaven Relativistic Heavy Ion Collider, RHIC  

SciTech Connect

The Relativistic Heavy Ion Collider, RHIC, is two counter-rotating rings with six interaction points. The RF Beam Control system for each ring will control two 28 MHz cavities for acceleration, and five 197 MHz cavities for preserving the 5 ns bunch length during 10 hour beam stores. Digital technology is used extensively in: Direct Digital Synthesis of rf signals and Digital Signal Processing for, the realization of state-variable feedback loops, real-time calculation of rf frequency, and bunch-by-bunch phase measurement of the 120 bunches. DSP technology enables programming the parameters of the feedback loops in order to obtain closed-loop dynamics that are independent of synchrotron frequency.

Brennan, J.M.; Campbell, A.; DeLong, J.; Hayes, T.; Onillon, E.; Rose, J.; Vetter, K.

1998-08-01

118

RF BEAM CONTROL SYSTEM FOR THE BROOKHAVEN RELATIVISTIC HEAVY ION COLLIDER, RHIC  

SciTech Connect

The Relativistic Heavy Ion Collider, RHIC, is two counter-rotating rings with six interaction points. The RF Beam Control system for each ring will control two 28 MHz cavities for acceleration, and five 197 MHz cavities for preserving the 5 ns bunch length during 10 hour beam stores. Digital technology is used extensively in: Direct Digital Synthesis of rf signals and Digital Signal Processing for, the realization of state-variable feedback loops, real-time calculation of rf frequency, and bunch-by-bunch phase measurement of the 120 bunches. DSP technology enables programming the parameters of the feedback loops in order to obtain closed-loop dynamics that are independent of synchrotron frequency.

BRENNAN,J.M.; CAMPBELL,A.; DELONG,J.; HAYES,T.; ONILLON,E.; ROSE,J.; VETTER,K.

1998-06-22

119

Accelerator summary  

NASA Astrophysics Data System (ADS)

A summary of the accelerator topics (CW electron accelerators, heavy ion colliders, kaon factories, polarized proton beams, and cooling rings) discussed in the 1984 conference on ``Intersections Between Particle and Nuclear Physics'' (Steamboat Springs) is presented. (AIP)

Mills, F. E.

1984-11-01

120

Accelerator summary  

SciTech Connect

A summary of the accelerator topics (CW electron accelerators, heavy ion colliders, kaon factories, polarized proton beams, and cooling rings) discussed in the 1984 conference on ''Intersections Between Particle and Nuclear Physics'' (Steamboat Springs) is presented. (AIP)

Mills, F.E.

1984-11-15

121

Focus on Accelerator and Beam Physics  

Microsoft Academic Search

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

Georg Hoffstaetter; Kwang-Je Kim; Ferdinand Willeke

2006-01-01

122

Notes on beam dynamics in linear accelerators  

SciTech Connect

A collection of notes, on various aspects of beam dynamics in linear accelerators, which were produced by the author during five years (1975 to 1980) of consultation for the LASL Accelerator Technology (AT) Division and Medium-Energy Physics (MP) Division is presented.

Gluckstern, R.L.

1980-09-01

123

Low-level RF signal processing for the Next Linear Collider Test Accelerator.  

National Technical Information Service (NTIS)

In the X-band accelerator system for the Next Linear Collider Test Accelerator (NLCTA), the Low Level RF (LLRF) drive system must be very phase stable, but concurrently, be very phase agile. Phase agility is needed to make the Stanford Linear Doubler (SLE...

S. Holmes C. Ziomek C. Adolphsen

1997-01-01

124

Beam Control for Ion Induction Accelerators  

SciTech Connect

Coordinated bending and acceleration of an intense space-charge-dominated ion beam has been achieved for the first time. This required the development of a variable waveform, precision, bi-polar high voltage pulser and a precision, high repetition rate induction core modulator. Waveforms applied to the induction cores accelerate the beam as the bi-polar high voltage pulser delivers a voltage ramp to electrostatic dipoles which bend the beam through a 90 degree permanent magnet quadrupole lattice. Further work on emittance minimization is also reported.

Sangster, T.C.; Ahle, L.

2000-02-17

125

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

SciTech Connect

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

Joshi, C. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States)

2007-05-15

126

Beam based alignment at the KEK accelerator test facility  

SciTech Connect

The KEK Accelerator Test Facility (ATF) damping ring is a prototype low emittance source for the NLC/JLC linear collider. To achieve the goal normalized vertical emittance {gamma}{var_epsilon}{sub {gamma}} = 20 nm-rad, magnet placement accuracy better than 30 mm must be achieved. Accurate beam-based alignment (BBA) is required. The ATF arc optics uses a FOBO cell with two horizontally focusing quadrupoles, two sextupoles and a horizontally defocusing gradient dipole, all of which must be aligned with BBA. BBA at ATF uses the quadrupole and sextupole trim windings to find the trajectory through the center of each magnet. The results can be interpreted to assess the accuracy of the mechanical alignment and the beam position monitor offsets.

Ross, M.; Nelson, J.; Woodley, M.; Wolski, A.

2002-06-14

127

SINGLE CRYSTAL NIOBIUM TUBES FOR PARTICLE COLLIDERS ACCELERATOR CAVITIES  

SciTech Connect

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

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

2013-02-28

128

High Energy Electron Cooling to Improve the Luminosity and Lifetime in Colliding Beam Machines.  

National Technical Information Service (NTIS)

Electron cooling can be applied to improve the performance of high energy colliding beams of hadrons and e exp - p storage rings. Normal beam excitations such as multiple scattering, resonance growth, or beam--beam interaction can be controlled, leading t...

D. Cline A. Garren H. Herr F. E. Mills C. Rubbia

1979-01-01

129

Design of the beam delivery system for the international linear collider  

Microsoft Academic Search

The beam delivery system for the linear collider focuses beams to nanometer sizes at its interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the ILC's physics goals. This paper describes the design details and status of the baseline configuration considered for the

A. Seryi; J. Amann; R. Arnold; F. Asiri; K. Bane; P. Bellomo; E. Doyle; A. Fasso; K. Jonghoon; L. Keller; K. Ko; Z. Li; T. Markiewicz; T. Maruyama; K. Moffeit; S. Molloy; Y. Nosochkov; N. Phinney; T. Raubenheimer; S. Seletskiy; S. Smith; C. Spencer; P. Tenenbaum; D. Walz; G. White; M. Woodley; M. Woods; L. Xiao; M. Anerella; A. Jain; A. Marone; B. Parker; O. Delferriere; O. Napoly; J. Payet; D. Uriot; N. Watson; I. Agapov; J.-L. Baldy; D. Schulte; G. Burt; A. Dexter; K. Buesser; W. Lohmann; L. Bellantoni; A. Drozhdin; V. Kashikhin; V. Kuchler; T. Lackowski; N. Mokhov; N. Nakao; T. Peterson; M. Ross; S. Striganov; J. Tompkins; M. Wendt; X. Yang; A. Enomoto; S. Kuroda; T. Okugi; T. Sanami; Y. Suetsugu; T. Tauchi; M. del Carmen Alabau; P. Bambade; J. Brossard; O. Dadoun; P. Burrows; G. Christian; C. Clarke; B. Constance; H. Dabiri Khah; A. Hartin; C. Perry; C. Swinson; A. Ferrari; G. Blair; S. Boogert; J. Carter; D. Angal-Kalinin; C. Beard; C. Densham; L. Fernandez-Hernando; J. Greenhalgh; P. Goudket; F. Jackson; J. Jones; A. Kalinin; L. Ma; P. Mcintosh; H. Yamamoto; T. Mattison; J. Carwardine; C. Saunders; R. Appleby; E. Torrence; J. Gronberg; T. Sanuki; Y. Iwashita; V. Telnov; D. Warner

2007-01-01

130

Beam Dynamics Effects of the Interaction Region Solenoid in a Linear Collider with a Crossing Angle  

Microsoft Academic Search

Future linear colliders may require a nonzero crossing angle between the two beams at the interaction point. This requirement in turn implies that the beams will pass through the strong interaction region (IR) solenoid with an angle, and thus that the component of the solenoidal field perpendicular to the beam trajectory is nonzero. The interaction of the beam and the

Tenenbaum; Peter G

2003-01-01

131

Beam dynamics of the interaction region solenoid in a linear collider due to a crossing angle  

Microsoft Academic Search

Future linear colliders may require a nonzero crossing angle between the two beams at the interaction point (IP). This requirement in turn implies that the beams will pass through the strong interaction region solenoid with an angle, and thus that the component of the solenoidal field perpendicular to the beam trajectory is nonzero. The interaction of the beam and the

P. Tenenbaum; J. Irwin; T. O. Raubenheimer

2003-01-01

132

ACCELERATOR PHYSICS ISSUES FOR FUTURE ELECTRON ION COLLIDERS.  

SciTech Connect

Interest continues to grow in the physics of collisions between electrons and heavy ions, and between polarized electrons and polarized protons [1,2,3]. Table 1 compares the parameters of some machines under discussion. DESY has begun to explore the possibility of upgrading the existing HERA-p ring to store heavy ions, in order to collide them with electrons (or positrons) in the HERA-e ring, or from TESLA [4]. An upgrade to store polarized protons in the HERA-p ring is also under discussion [1]. BNL is considering adding polarized electrons to the RHIC repertoire, which already includes heavy and light ions, and polarized protons. The authors of this paper have made a first pass analysis of this ''eRHIC'' possibility [5]. MIT-BATES is also considering electron ion collider designs [6].

PEGGS,S.; BEN-ZVI,I.; KEWISCH,J.; MURPHY,J.

2001-06-18

133

Explore the possibility of accelerating polarized He-3 beam in RHIC  

SciTech Connect

As the world's first high energy polarized proton collider, RHIC has made significant progresses in measuring the proton spin structure in the past decade. In order to have better understanding of the contribution of up quarks and down quarks to the proton spin structure, collisions of high energy polarized neutron beams are required. Polarized He-3 beams offer an effectiveway to provide polarized neutron beams. In this paper, we present studies of accelerating polarized He-3 in RHIC with the current dual snake configuration. Possibilities of adding two more pairs of snakes for accelerating polarized He-3 were explored. Results of six snake configuration in RHIC are also reported in the paper.

Bai M.; Courant, E.; Fischer, W.; Ptitsyn, V.; Roser, T.

2012-05-20

134

Discrete beam acceleration in uniform waveguide arrays  

SciTech Connect

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

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

2011-08-15

135

Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators  

SciTech Connect

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

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

2011-03-01

136

Negative ion beam acceleration and transport  

SciTech Connect

The optimum conditions for focusing a negative ion beam are discussed. The distribution of the current between the Faraday cup and a large ring collector, surrounding this cup, has been investigated experimentally and theoretically, at constant extraction voltage (1.9 kV), with the acceleration voltage being varied in a wide range. The effects of beam space charge, negative ion temperature, and stripping are analyzed.

Michaut, C.; Devynck, P.; Bacal, M.; Sledziewski, Z.; Valckx, F.P.G. (Laboratoire de Physique des Milieux Ionises, Laboratoire du C.N.R.S., Ecole Polytechnique, 91128 Palaiseau (France)); Whealton, J.H.; Raridon, R.J. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States))

1992-04-01

137

Accelerating diffraction-free beams in photonic lattices.  

PubMed

We study nondiffracting accelerating paraxial optical beams in periodic potentials, in both the linear and the nonlinear domains. In particular, we show that only a unique class of z-dependent lattices can support a true accelerating diffractionless beam. Accelerating lattice solitons, autofocusing beams and accelerating bullets in optical lattices are systematically examined. PMID:24686692

Makris, K G; Kaminer, I; El-Ganainy, R; Efremidis, N K; Chen, Zhigang; Segev, M; Christodoulides, D N

2014-04-01

138

SLAC (Stanford Linear Accelerator Center) Linac as Used in the SLC Collider.  

National Technical Information Service (NTIS)

The linac of the SLAC Linear Collider (SLC) must accelerate three high intensity bunches on each linac pulse from 1.2 GeV to 50 GeV with minimal increase of the small transverse emittance. The procedures and adjustments used to obtain this goal are outlin...

J. T. Seeman G. Abrams C. Adolphsen W. Atwood K. L. F. Bane

1989-01-01

139

Nonlinear particle dynamics map of wakefield acceleration in a linear collider.  

National Technical Information Service (NTIS)

The performance of a wakefield accelerator in a high energy collider application is analyzed. In order to carry out this task, it is necessary to construct a strawman design system (no matter how preliminary) and build a code of the systems approach. A no...

T. Tajima S. Cheshkov W. Horton K. Yokoya

1998-01-01

140

Particle dynamics and its consequences in wakefield acceleration in a high energy collider.  

National Technical Information Service (NTIS)

The performance of a wakefield accelerator in a high energy collider application is analyzed by use of a nonlinear dynamics map built on a simple theoretical model of the wakefield generated by the laser pulse (or whatever other method) and a code based o...

S. Cheshkov T. Tajima W. Horton K. Yokoya

1998-01-01

141

Theories of statistical equilibrium in electron-positron colliding-beam storage rings  

SciTech Connect

In this lecture I introduce you to some recent theoretical work that represents a significant and long overdue departure from the mainstream of ideas on the physics of colliding- beam storage rings. The goal of the work in question is to understand analytically - without recourse to computer simulation - the role that dissipation and noise play in the observed colliding-beam behavior of electron-positron storage rings.

Schonfeld, J.F.

1985-01-01

142

Estimation of electron-cloud effect on NICA collider  

NASA Astrophysics Data System (ADS)

The preliminary results from simulating the formation of electron clouds in the NICA collider using the ECLOUD program package are presented. Requirements for the acceleration chamber of the NICA collider for a gold nuclei beam are discussed.

Philippov, A. V.; Monchinsky, V. A.; Kuznetsov, A. B.

2010-12-01

143

Technical Challenges and Scientific Payoffs of Muon BeamAccelerators for Particle Physics  

SciTech Connect

Historically, progress in particle physics has largely beendetermined by development of more capable particle accelerators. Thistrend continues today with the recent advent of high-luminosityelectron-positron colliders at KEK and SLAC operating as "B factories,"the imminent commissioning of the Large Hadron Collider at CERN, and theworldwide development effort toward the International Linear Collider.Looking to the future, one of the most promising approaches is thedevelopment of muon-beam accelerators. Such machines have very highscientific potential, and would substantially advance thestate-of-the-art in accelerator design. A 20-50 GeV muon storage ringcould serve as a copious source of well-characterized electron neutrinosor antineutrinos (a Neutrino Factory), providing beams aimed at detectorslocated 3000-7500 km from the ring. Such long baseline experiments areexpected to be able to observe and characterize the phenomenon ofcharge-conjugation-parity (CP) violation in the lepton sector, and thusprovide an answer to one of the most fundamental questions in science,namely, why the matter-dominated universe in which we reside exists atall. By accelerating muons to even higher energies of several TeV, we canenvision a Muon Collider. In contrast with composite particles likeprotons, muons are point particles. This means that the full collisionenergy is available to create new particles. A Muon Collider has roughlyten times the energy reach of a proton collider at the same collisionenergy, and has a much smaller footprint. Indeed, an energy frontier MuonCollider could fit on the site of an existing laboratory, such asFermilab or BNL. The challenges of muon-beam accelerators are related tothe facts that i) muons are produced as a tertiary beam, with very large6D phase space, and ii) muons are unstable, with a lifetime at rest ofonly 2 microseconds. How these challenges are accommodated in theaccelerator design will be described. Both a Neutrino Factory and a MuonCollider require large numbers of challenging superconducting magnets,including large aperture solenoids, closely spaced solenoids withopposing fields, shielded solenoids, very high field (~;40-50 T)solenoids, and storage ring magnets with a room-temperature midplanesection. Uses for the various magnets will be outlined, along withR&D plans to develop these and other required components of suchmachines.

Zisman, Michael S.

2007-09-25

144

Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider  

Microsoft Academic Search

To reach design luminosity, the International Linear Collider (ILC) must be able to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittances are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like

S. Araki; H. Hayano; Y. Higashi; Y. Honda; K. Kanazawa; K. Kubo; T. Kume; M. Kuriki; S. Kuroda; M. Masuzawa; T. Naito; T. Okugi; R. Sugahara; T. Takahashi; T. Tauchi; N. Terunuma; N. Toge; J. Urakawa; V. Vogel; H. Yamaoka; K. Yokoya; J. Gao; W. Liu; G. Pei; J. Wang; B. Grishanov; P. Logachev; F. Podgorny; V. Telnov; D. Angal-Kalinin; R. Appleby; J. Jones; A. Kalinin; O. Napoly; J. Payet; H. Braun; D. Schulte; F. Zimmermann; Y. Iwashita; T. Mihara; P. Bambade; J. Gronberg; M. Kumada; S. Danagoulian; S. Mtingwa; N. Delerue; D. Howell; A. Reichold; D. Urner; J. Choi; J.-Y. Huang; H. S. Kang; E.-S. Kim; S. Kim; I. S. Ko; P. Burrows; G. Christian; S. Molloy; G. White; I. Agapov; G. Blair; G. Boorman; J. Carter; C. Driouichi; M. Price; N. Walker; K. Bane; A. Brachmann; T. Himel; T. Markiewicz; J. Nelson; N. Phinney; M. Pivi; T. Raubenheimer; M. Ross; R. Ruland; A. Seryi; C. Spencer; P. Tenenbaum; M. Woodley; S. Boogert; A. Liapine; S. Malton; E. Torrence; T. Sanuki; T. Suehara

2005-01-01

145

FOCUSING AND ACCELERATION OF BUNCHED BEAMS  

SciTech Connect

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

PARSA,Z.; ZADOROZHNY,V.

2000-04-07

146

POLARIZED ION SOURCES FOR HIGH ENERGY ACCELERATORS AND COLLIDERS  

SciTech Connect

The recent progress in polarized ion source development is reviewed. In dc operation a 1.0 mA polarized H{sup -} ion current is now available from the Optically-Pumped Polarized Ion Source (OPPIS). In pulsed operation a 10 mA polarized H{sup -} ion current was demonstrated at the TRIUMF pulsed OPPIS test bench and a 3.5 mA peak current was obtained from an Atomic Beam Source (ABS) at the INR Moscow test bench. The possibilities for future improvements with both techniques are discussed. A new OPPIS for RHIC spin physics is described. The OPPIS reliably delivered polarized beam for the polarized run at RHIC. The results obtained with a new pulsed ABS injector for the IUCF Cooler Ring are also discussed.

ZELENSKI,A.N.

2000-10-16

147

POLARIZED ION SOURCES FOR HIGH ENERGY ACCELERATORS AND COLLIDERS  

SciTech Connect

The recent progress in polarized ion source development is reviewed. In dc operation a 1.0 mA polarized H{sup -} ion current is now available from the Optically-Pumped Polarized Ion Source (OPPIS) . In pulsed operation a 10 mA polarized H{sup -} ion current was demonstrated at the TRIUMF pulsed OPPIS test bench and a 3.5 mA peak current was obtained from an Atomic Beam Source (ABS) at the INR Moscow test bench. The possibilities for future improvements with both techniques are discussed. A new OPPIS for RHIC spin physics is described. The OPPIS reliably delivered polarized beam for the polarized run at RHIC. The results obtained with a new pulsed ABS injector for the IUCF Cooler Ring are also discussed.

ZELENSKI,A.N.

2000-10-16

148

Polarized ion sources for high-energy accelerators and colliders  

NASA Astrophysics Data System (ADS)

The recent progress in polarized ion source development is reviewed. In dc operation a 1.0 mA polarized H- ion current is now available from the Optically-Pumped Polarized Ion Source (OPPIS). In pulsed operation a 10 mA polarized H- ion current was demonstrated at the TRIUMF pulsed OPPIS test bench and a 2.5 mA peak current was obtained from an Atomic Beam Source (ABS) at the INR Moscow test bench. The possibilities for future improvements with both techniques are discussed. A new OPPIS for RHIC spin physics is described. The OPPIS reliably delivered polarized beam for the polarized run at RHIC. The results obtained with a new pulsed ABS injector for the IUCF Cooler Ring are also discussed. .

Zelenski, A. N.

2001-06-01

149

Alignment measurement of an X-band accelerator structure using beam induced dipole signals  

NASA Astrophysics Data System (ADS)

Precise beam-to-structure alignment is critical for the acceleration of small emittance beams in linear accelerators. For the Next Linear Collider (NLC), a prototype accelerator structure has been developed in which the beam induced dipole mode signals can be readily accessed and processed to extract alignment information. In a test in the SLC linac, we used these signals to measure the internal alignment of the structure and to steer the beam in an attempt to minimize its wakefield. We used a second bunch to directly measure the wakefield and inferred from the results that a better than 40 micron alignment had been achieved. In this paper, we review these results and describe how we want to implement this alignment scheme for the approximately ten thousand structures in the NLC.

Adolphsen, Chris

1998-12-01

150

Adiabatic matching section for plasma accelerated beams  

NASA Astrophysics Data System (ADS)

An adiabatic matching section is discussed as option to control the divergence and emittance growth of a beam exiting a plasma channel. Based on a general analytical solution of a focusing channel with varying focusing strength, a focusing profile is proposed which allows for a fast expansion of the beam size while keeping the emittance growth minimal. The solution is also applicable to other cases, e.g., the matching of a positron source to the downstream accelerating section, which are, however, not discussed in this contribution.

Floettmann, Klaus

2014-05-01

151

High-powered pulsed-ion-beam acceleration and transport  

SciTech Connect

The state of research on intense ion beam acceleration and transport is reviewed. The limitations imposed on ion beam transport by space charge effects and methods available for neutralization are summarized. The general problem of ion beam neutralization in regions free of applied electric fields is treated. The physics of acceleration gaps is described. Finally, experiments on multi-stage ion acceleration are summarized.

Humphries, S. Jr.; Lockner, T.R.

1981-11-01

152

Production of high power microwaves for particle acceleration with an FEL bunched electron beam  

NASA Astrophysics Data System (ADS)

Among the studies in the framework of high gradient linear electron-positron collider research, the Two-Beam Accelerator (TBA) is a very promising concept, and two projects are in progress, the Compact Linear Collider project at CERN (W. Schnell, Report no. CERN SL/92-51 and CLIC note 184; K. Hübner, CERN/PS 92-43, CLIC note 176; S. Van der Meer, CERN/PS 89-50, CLIC note 97.) and the Relativistic Klystron-TBA project at LBNL (Technical Review Committee, International Linear Collider Technical Review Committee Report 1995, SLAC-R-95-471, 1995). In a TBA an extremely intense low-energy electron beam, called the drive beam, is bunched at the desired operating frequency, and upon passing through resonant cavities generates radio-frequency power for accelerating the main beam. Among the different approaches to the production of a suitable drive beam, the use of an FEL has been proposed and is under active study at CEA/CESTA.

Gardelle, J.; Lefevre, T.; Marchese, G.; Padois, M.; Rullier, J. L.; Donohue, J. T.

1999-06-01

153

Beam Dynamics of the Interaction Region Solenoid in a Linear Collider Due to a Crossing Angle.  

National Technical Information Service (NTIS)

Future linear colliders may require a nonzero crossing angle between the two beams at the interaction point. This requirement in turn implies that the beams will pass through the strong interaction region (IR) solenoid with an angle, and thus that the com...

P. Tenenbaum J. Irwin T. O. Raubenheimer

2003-01-01

154

Working group summary: Machine design for the {mu}{sup +} - {mu}{sup {minus}} collider  

SciTech Connect

We summarize the discussions of the working group on Machine Design. The scope of the working group included the entire accelerator system from beam cooling to the collider and the collider ring itself. Particular topics that were discussed in some detail included acceleration options, magnet designs (including the accelerator arcs and collider ring), instabilities, particularly in the collider ring, and lattice issues, particularly in the interaction regions (IRs). Considerable challenges remain in defining a complete machine design for the collider.

Hirata, K.; Neuffer, D.; Autin, B. [and others

1995-10-01

155

600 kV Modulator Design for the SLAG Next Linear Collider Test Accelerator  

Microsoft Academic Search

Preliminary design for the SLAC Next Linear Collider Test Accelerator (NLCTA) requires a pulse power source to produce a 600 kV, 600 A, 1.4 μs, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a microperveance of 1.25 at â 100 MW peak RF power. The design goals for the

K. Harris; J. deLamare; V. Nesterov; R. Cassel

1992-01-01

156

Method and apparatus for varying accelerator beam output energy  

DOEpatents

A coupled cavity accelerator (CCA) accelerates a charged particle beam with rf energy from a rf source. An input accelerating cavity receives the charged particle beam and an output accelerating cavity outputs the charged particle beam at an increased energy. Intermediate accelerating cavities connect the input and the output accelerating cavities to accelerate the charged particle beam. A plurality of tunable coupling cavities are arranged so that each one of the tunable coupling cavities respectively connect an adjacent pair of the input, output, and intermediate accelerating cavities to transfer the rf energy along the accelerating cavities. An output tunable coupling cavity can be detuned to variably change the phase of the rf energy reflected from the output coupling cavity so that regions of the accelerator can be selectively turned off when one of the intermediate tunable coupling cavities is also detuned.

Young, Lloyd M. (Los Alamos, NM)

1998-01-01

157

Beam transport issues in high current linear accelerators  

SciTech Connect

Stable beam transport may be the limiting factor in the development of a new generation of high current linear induction accelerators. Several important beam stability topics, including radial oscillations induced by an accelerating gap, the diocotron, resistive wall, and cyclotron maser instabilities, and the transverse beam breakup and image displacement instabilities. At present image displacement appears to represent the most serious limitation to high current beam transport in linear accelerator structures. 13 refs.

Miller, R.B.; Poukey, J.W.; Epstein, B.G.; Shope, S.L.; Genoni, T.C.; Franz, M.; Godfrey, B.B.; Adler, R.J.; Mondelli, A.

1981-06-01

158

Linear collider development at SLAC  

SciTech Connect

Linear collider R&D at SLAC comprises work on the present Stanford Linear Collider (SLC) and work toward the next linear collider (NLC). Recent SLC developments are summarized. NLC studies are divided into hardware-based and theoretical. We report on the status of the NLC Test Accelerator (NLCTA) and the final focus test beam (FFTB), describe plans for ASSET, an installation to measure accelerator structure wakefields, and mention IR design developments. Finally we review recent NLC theoretical studies, ending with the author`s view of next linear collider parameter sets.

Irwin, J.

1993-08-01

159

Beam Dynamics Effects of the Interaction Region Solenoid in a Linear Collider with a Crossing Angle  

SciTech Connect

Future linear colliders may require a nonzero crossing angle between the two beams at the interaction point. This requirement in turn implies that the beams will pass through the strong interaction region (IR) solenoid with an angle, and thus that the component of the solenoidal field perpendicular to the beam trajectory is nonzero. The interaction of the beam and the solenoidal field will cause optical effects, such as dispersion and deflection of the beam, and synchrotron radiation effects. For a purely solenoidal field, the optical effects which are relevant to luminosity exactly cancel at the IP when the influence of the solenoid's fringe field is taken into account. Beam size growth due to synchrotron radiation in the solenoid is proportional to the fifth power of the product of the solenoidal field, the length of the solenoid, and the crossing angle. Examples based on proposed linear collider detector solenoid configurations are presented.

Tenenbaum, Peter G

2003-02-03

160

A test of bunched beam stochastic cooling in the Fermilab Tevatron collider  

Microsoft Academic Search

In order to double the integrated luminosity of the Tevatron collider in the next running period, a 4-8-GHz bunched-beam betatron stochastic cooling system has been designed. The horizontal and vertical emittances of the protons and antiprotons will be cooled to counteract the effects of power supply noise, beam-beam interaction, and intrabeam scattering. A vertical proton test system has been installed

G. Jackson; E. Buchanan; J. Budlong; E. Harms; P. Hurh; J. Marriner; R. Pasquinelli; D. Peterson; P. Seifrid; D. Rohde; D. Voy

1991-01-01

161

E-Beam Driven Accelerators: Working Group Summary  

SciTech Connect

The working group has identified the parameters of an afterburner based on the design of a future linear collider. The new design brings the center of mass energy of the collider from 1 to 2 TeV. The afterburner is located in the final focus section of the collider, operates at a gradient of {approx}4 GeV/m, and is only about 125 m long. Very important issues remain to be addressed, and include the physics and design of the positron side of the afterburner, as well as of the final focus system. Present plasma wakefield accelerator experiments have reached a level of maturity and of relevance to the afterburner, that make it timely to involve the high energy physics and accelerator community in the afterburner design process. The main result of this working group is the first integration of the designs of a future linear collider and an afterburner.

Muggli, P.; /Southern California U.; Ng, J.S.T.; /SLAC

2005-07-12

162

Accelerator development for a radioactive beam facility based on ATLAS.  

SciTech Connect

The existing superconducting linac ATLAS is in many respects an ideal secondary beam accelerator for an ISOL (Isotope separator on-line) type radioactive beam facility. Such a facility would require the addition of two major accelerator elements: a low charge state injector for the existing heavy ion linac, and a primary beam accelerator providing 220 MV of acceleration for protons and light ions. Development work for both of these elements, including the option of superconducting cavities for the primary beam accelerator is discussed.

Shepard, K. W.

1998-01-08

163

Generation of periodic accelerating structures in plasma by colliding laser pulses  

Microsoft Academic Search

A mechanism for generating large (>1 GeV\\/m) accelerating wakes in a plasma is proposed. Two slightly detuned counterpropagating laser beams, an ultrashort timing pulse and a long pump, exchange photons and deposit the recoil momentum in plasma electrons. This produces a localized region of electron current, which acts as a virtual electron beam, inducing intense plasma wakes with phase velocity

G. Shvets; N. J. Fisch; A. Pukhov; J. Meyer-Ter-Vehn

1999-01-01

164

Beam-Beam Interaction at the PEP-II E+ E- Collider  

SciTech Connect

The PEP-II B-Factory at SLAC (3.1 GeV e{sup +} x 9.0 GeV e{sup -}) operated from 1999 to 2008, delivering luminosity to the BaBar experiment. The design luminosity was reached after one and a half years of operation. PEP-II ultimately surpassed by four times its design luminosity reaching 1.21 x 10{sup 34} cm{sup -2} s{sup -1}. It also set world records for stored beam currents of 2.1 A e{sup -} and 3.2 A e{sup +}. Continuous injection was implemented with BaBar taking data. The total delivered luminosity to the BaBar detector was 557.4 fb{sup -1} spanning five upsilon resonances. PEP-II was constructed by SLAC, LBNL, and LLNL with help from BINP, IHEP, the BaBar collaboration, and the US DOE OHEP. In order to reach four times the design luminosity the PEP-II accelerator had to manage higher beam currents, lower {beta}{sub y}*s, more bunches, and increased beam-beam tune shifts. In this note the effects of these changes on the beam-beam interaction are discussed.

Seeman, J.; Sullivan, M.; /SLAC

2012-06-22

165

Solid Target Studies for Muon Colliders And Neutrino Beams  

SciTech Connect

This paper presents preliminary results from an ongoing post-irradiation analysis of materials that have been irradiated at the Brookhaven National Laboratory (BNL) Isotope facility. The effort is part of an experimental study that focuses on how prone to irradiation damage these materials are and thus what is their potential in playing the role of high power targets in the neutrino superbeam and the muon collider initiatives.

Simos, N.; Kirk, H.; Ludewig, H.; Thieberger, P.; Weng, W.T.; Trung, P.T.; /Brookhaven; McDonald, K.; /Princeton U.; Sheppard, J.; /SLAC; Yoshimura, K.; Hayato, Y.; /KEK, Tsukuba

2006-05-10

166

High Energy Accelerator and Colliding Beam User Group. Progress Report.  

National Technical Information Service (NTIS)

The OPAL project at LEP has begun to dominate the research activites at Maryland. A very large new laboratory has been commissioned in the Physics Building. In this laboratory wire chambers and pads are being assembled and tested before shipment to CERN f...

1985-01-01

167

Design of an accelerating cavity for the Superconducting Super Collider Low-Energy Booster  

SciTech Connect

This paper presents the history and current status of the design of the accelerator cavity to be incorporated into the Low-Energy Booster (LEB) of the Superconducting Super Collider (SSC). The LEB is a proton synchrotron, 540 meters in circumference, and having 108 buckets around the ring. Acceleration programs, each 50 msec long, take place at a rate of 10 per second. The beta change of the particles from injection to extraction is from 0.8 to 0.997. Since the rf excitation frequency must track beta, the rf frequency must shift from 47.5 to 60 MHz over the 50-msec acceleration program. The cavity will use ferrite in a perpendicular control bias mode to effect the require tuning. 4 refs., 1 fig.

Friedrichs, C.C.; Walling, L. (Los Alamos National Lab., NM (USA)); Campbell, B.M. (Superconducting Super Collider Lab., Dallas, TX (USA))

1991-01-01

168

Linear accelerator in the space: The beam experiment aboard rocket.  

National Technical Information Service (NTIS)

On July 13, 1989 the BEAM experiment Aboard Rocket (BEAR) linear accelerator was successfully launched and operated in space. The flight demonstrated that a neutral hydrogen beam could be successfully propagated in an exoatmospheric environment. The accel...

P. G. O'Shea T. A. Butler M. T. Lynch K. F. McKenna M. B. Pongratz

1990-01-01

169

Impact of three-dimensional polarization profiles on spin-dependent measurements in colliding beam experiments  

SciTech Connect

We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the polarization-weighted luminosity (figure of merit) in single and double spin measurements in colliding beam experiments. Applications to RHIC are discussed.

Fischer W.; Bazilevsky, A.

2012-04-02

170

Environmental Phase Stabilization of the Next Linear Collider Test Accelerator's Low-Level RF System  

NASA Astrophysics Data System (ADS)

The Next Linear Collider Test Accelerator (NLCTA) requires an extremely phase stable low-level RF (LLRF) drive system. In order to help achieve this both the LLRF drive system and the LLRF monitor system have been provided controlled environments in which to operate. In this paper we describe the mechanical design and layout of the thermal and mechanical isolation systems for the LLRF, the performance of the isolation systems and the effects on phase stability of the LLRF system due to the isolation systems. These systems include temperature stable enclosures, active thermal systems, passive thermal systems, temperature stable water systems, and mechanically isolated support structures.

Wilson, Zane J.

1997-05-01

171

A 200 MHz 35 MW Multiple Beam Klystron for Accelerator Applications Final Report  

SciTech Connect

Calabazas Creek Research, Inc. (CCR) performed initial development of a compact and reliable 35 MW, multiple beam klystron (MBK) at 200 MHz with a pulse length of 0.125 ms and a 30 Hz repetition rate. The device was targeted for acceleration and ionization cooling of a muon collider, but there are several other potential applications in this frequency range. The klystron uses multiple beams propagating in individual beam tunnels to reduce space charge and allow reduction in the accelerating voltage. This allows a significant reduction in length over a single beam source. More importantly this allows more efficient and less expensive power supplies. At 200 MHz, the interaction circuit for a single beam klystron would be more than six meters long to obtain 50% efficiency and 50 dB gain. This would require a beam voltage of approximately 400 kV and current of 251 A for a microperveance of 1.0. For an eight beam MBK with the same beam perveance, a three meter long interaction circuit achieves the same power and gain. Each beam operates at 142 kV and 70A. The Phase I demonstrated that this device could be fabricated with funding available in a Phase II program and could achieve the program specifications.

R. Lawrence Ives; Michael Read; Patrick Ferguson; David Marsden

2011-11-28

172

Frontiers of accelerator instrumentation  

SciTech Connect

New technology has permitted significant performance improvements of established instrumentation techniques including beam position and profile monitoring. Fundamentally new profile monitor strategies are required for the next generation of accelerators, especially linear colliders (LC). Beams in these machines may be three orders of magnitude smaller than typical beams in present colliders. In this paper we review both the present performance levels achieved by conventional systems and present some new ideas for future colliders.

Ross, M.

1992-08-01

173

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

SciTech Connect

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

Carol Johnstone

2004-08-23

174

Discussion of parameters, lattices and beam stability for a 200-TeV low-field collider  

SciTech Connect

Recently, it has been suggested that improved technology and reduced costs in remotely-drilled small-diameter tunnels, coupled with improvements in robotic technology, may make the original concept of the ``desertron`` more realistic and affordable. In this concept, a long, small-diameter tunnel is drilled (<{approximately}1m diameter ``sewer`` pipe) and filled with long, low-cost magnets, which are installed and serviced robotically. To obtain high-energy then requires low cost magnets, which are iron-dominated ``superferric`` magnets (B{approximately}2 T). A large circumference is then required ({approximately}1000 km for {approximately}100 TeV/beam). Table 1 shows parameters for a 200 TeV proton-proton collider, based on the premise of a large low-cost ring with super-ferric magnets. While outline designs for a low-cost {approximately}2T dipole have been initiated, an accelerator requires beam stability, which means quadrupole fields for focusing, as well as sextupoles for chromatic correction, and further design tolerances and correctors to obtain sufficiently linear fields. Previously we have developed initial lattices and dynamic motion discussions for the earlier 40 TeV incarnation of the superferric supercollider. In this note we apply those results to initiate discussions of the dynamic requirements of this 200 TeV collider.

Neuffer, D.

1996-03-01

175

Self-accelerating optical beams in highly nonlocal nonlinear media.  

PubMed

We find self-accelerating beams in highly nonlocal nonlinear optical media, and show that their propagation dynamics is strongly affected by boundary conditions. Specifically for the thermal optical nonlinearity, the boundary conditions have a strong impact on the beam trajectory: they can increase the acceleration during propagation, or even cause beam bending in a direction opposite to the initial trajectory. Under strong self-focusing, the accelerating beam decomposes into a localized self-trapped beam propagating on an oscillatory trajectory and a second beam which accelerates in a different direction. We augment this study by investigating the effects caused by a finite aperture and by a nonlinear range of a finite extent. PMID:22109397

Bekenstein, Rivka; Segev, Mordechai

2011-11-21

176

Polarized hadrons beams in NICA project  

NASA Astrophysics Data System (ADS)

The report is dedicated to the problem of formation and maintenance of polarized proton and deuteron colliding beams in the collider of Nuclotron-based Ion Collider Facility (NICA). The NICA project is under development at JINR presently. The schemes of polarized proton and deuteron beams acceleration in the superconducting synchrotron Nuclotron and formation of both longitudinal and transverse particle polarization in the collider are presented. The problems of long term conservation of the beams polarization in the collider are discussed as well.

Meshkov, I. N.; Filatov, Yu N.

2011-05-01

177

Beam dynamics of the interaction region solenoid in a linear collider due to a crossing angle  

NASA Astrophysics Data System (ADS)

Future linear colliders may require a nonzero crossing angle between the two beams at the interaction point (IP). This requirement in turn implies that the beams will pass through the strong interaction region solenoid with an angle, and thus that the component of the solenoidal field perpendicular to the beam trajectory is nonzero. The interaction of the beam and the solenoidal field in the presence of a crossing angle will cause optical effects not observed for beams passing through the solenoid on axis; these effects include dispersion, deflection of the beam, and synchrotron radiation effects. For a purely solenoidal field, the optical effects which are relevant to luminosity exactly cancel at the IP when the influence of the solenoid’s fringe field is taken into account. Beam size growth due to synchrotron radiation in the solenoid is proportional to the fifth power of the product of the solenoidal field, the length of the solenoid, and the crossing angle. Examples based on proposed linear collider detector solenoid configurations are presented.

Tenenbaum, P.; Irwin, J.; Raubenheimer, T. O.

2003-06-01

178

Experiments of an intense H(sup -) ion beam acceleration.  

National Technical Information Service (NTIS)

An intense H(sup -) beam of a single beamlet is extracted from a large multicusp plasma source operated with cesium seeding. The H(sup -) beams are accelerated up to 100keV by a single-stage or a two-stage electrode system. Spatial profiles of the beams a...

A. Ando Y. Takeiri O. Kaneko Y. Oka K. Tsumori

1995-01-01

179

The production of accelerated radioactive ion beams  

SciTech Connect

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

Olsen, D.K.

1993-11-01

180

A method for free electron acceleration of particle beams  

SciTech Connect

The large electric fields associated with sources of space charge have led to numerous proposals for possible collective (space-charge-based) accelerators. Traditionally, these schemes involve either magnetic fields or background ions (a plasma) to contain the space charge. This Letter proposes a new technique for particle acceleration that directly uses the large space charge fields of freely moving electron beams. Such free electron accelerators promise eventual accelerating gradients in excess of 10 GV/m.

Larson, D.J. (Superconducting Super Collilder Laboratory, 2550 Beckleymeade Avenue, MS 1040, Dallas, Texas 75237 (United States))

1993-08-09

181

Accelerators (3/5)  

ScienceCinema

1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

None

2011-10-06

182

Accelerators (5/5)  

ScienceCinema

1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

None

2011-10-06

183

Accelerators (4/5)  

ScienceCinema

1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

None

2011-10-06

184

Characteristics of an electron-beam rocket pellet accelerator  

SciTech Connect

A proof-of-principle (POP) electron-beam pellet accelerator has been developed and used for accelerating hydrogen and deuterium pellets. An intact hydrogen pellet was accelerated to a speed of 460 m/s by an electron beam of 13.5 keV. 0.3 A, and 2 ms. The maximum speed is limited by the acceleration path length (0.4 m) and pellet integrity. Experimental data have been collected for several hundred hydrogen pellets, which were accelerated by electron beams with parameters of voltage up to 16 kV, current up to 0.4 A, and pulse length up to 10 ms. Preliminary results reveal that the measured burn velocity increases roughly with the square of the beam voltage, as the theoretical model predicts. The final pellet velocity is proportional to the exhaust velocity, which increases with the beam power. To reach the high exhaust velocity needed for accelerating pellets to >1000 m/s, a new electron gun, with its cathode indirectly heated by a graphite heater and an electron beam, is being developed to increase beam current and power. A rocket casing or shell around the pellet has been designed and developed to increase pellet strength and improve the electron-rocket coupling efficiency. We present the characteristics of this pellet accelerator, including new improvements. 13 refs., 6 figs.

Tsai, C.C.; Foster, C.A.; Milora, S.L.; Schechter, D.E.

1991-01-01

185

Acceleration to collisions for the {mu}{sup +}{minus}{mu}{sup {minus}} collider  

SciTech Connect

We discuss the problem of transforming muon beam bunches from a low-energy cooled state ({ital E}{sub {mu}}{approximately}1 GeV) to short, high-energy bunches matched to high-energy collision conditions ({ital E}{sub {mu}}{approximately}2 TeV). In this process the beam energy must increase by {approximately} three orders of magnitude, while the bunch length must be reduced by {approximately} two orders of magnitude (to {approximately}3 mm), while beam emittance dilution and beam losses, particularly through decay, must be minimized. From general considerations, we discuss possible acceleration scenarios including rapid-cycling synchrotron and recirculating linac options. The presently favored choice is a multi-stage recirculating linac system, which is discussed, and initial simulations of possible scenarios are presented. Future directions for development are discussed. {copyright} {ital 1996 American Institute of Physics.}

Neuffer, D.V. [Fermilab, P.O. Box 500, Batavia, Illinois 60510 (United States)

1996-05-01

186

Acceleration to collisions for the {mu}{sup +}-{mu}{sup {minus}} collider  

SciTech Connect

The authors discuss the problem of transforming muon beam bunches from a low-energy cooled state (E{sub {mu}} {approximately} 1 GeV) to short, high-energy bunches matched to high-energy collision conditions (E{sub {mu}} {approximately} 2 TeV). In this process the beam energy must increase by {approximately} three orders of magnitude, while the bunch length must be reduced by {approximately} two orders of magnitude (to {approximately} 3mm), while beam emittance dilution and beam losses, particularly through decay, must be minimized. From general considerations, they discuss possible acceleration scenarios including rapid-cycling synchrotron and recirculating linac options. The presently favored choice is a multi-stage recirculating linac system, which is discussed, and initial simulations of possible scenarios are presented. Future directions for development are discussed.

Neuffer, D.V.

1996-01-01

187

Trajectory measurements and correlations in the final focus beam line at the KEK Accelerator Test Facility  

NASA Astrophysics Data System (ADS)

The Accelerator Test Facility 2 (ATF2) commissioning group aims to demonstrate the feasibility of the beam delivery system of the next linear colliders (ILC and CLIC) as well as to define and to test the tuning methods. As the design vertical beam sizes of the linear colliders are about few nanometers, the stability of the trajectory as well as the control of the aberrations are very critical. ATF2 commissioning started in December 2008, and thanks to submicron resolution beam position monitors (BPMs), it has been possible to measure the beam position fluctuation along the final focus of ATF2 during the 2009 runs. The optics was not the nominal one yet, with a lower focusing to make the tuning easier. In this paper, a method to measure the noise of each BPM every pulse, in a model-independent way, will be presented. A method to reconstruct the trajectory’s fluctuations is developed which uses the previously determined BPM resolution. As this reconstruction provides a measurement of the beam energy fluctuations, it was also possible to measure the horizontal and vertical dispersion function at each BPMs parasitically. The spatial and angular dispersions can be fitted from these measurements with uncertainties comparable with usual measurements.

Renier, Y.; Bambade, P.; Tauchi, T.; White, G. R.; Boogert, S.

2013-06-01

188

Radioactive beams with the HHIRF accelerators  

SciTech Connect

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

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

1991-01-01

189

Summary of beam coupling impedance measurements and simulations of collider liner with pumping holes or slots  

SciTech Connect

We report the results of measurements using the wire method and numerical simulations using the code HFSS (High-Frequency Structure Simulator) of the beam coupling impedance of the proposed liner for the collider ring of the SSC. We compare the results of the measurements and simulations to analytical estimates by R. Gluckstern and S. Kurennoy, and conclude that the additional coupling impedance introduced by a liner with pumping holes can be acceptable.

Walling, L.; Ruiz, E.D.; Spayd, N.

1994-04-01

190

Transition Radiation Detector in the D0 colliding beam experiment at Fermilab  

SciTech Connect

The construction, operation and response of the Transition Radiation Detector (TRD) at DO colliding beam experiment at Fermilab are presented. The use of the TRD signal to enhance electron identification and hadronic rejection in the multiparticle background characteristic for the antiproton-proton interactions at the center-of-mass energy of 1.8 TeV is also described and results are discussed.

Piekarz, H.

1995-04-01

191

Colliding beam measurements of ICR collision processes between alkali ion-atom pairs  

Microsoft Academic Search

A colliding beam ion cyclotron resonance experiment has been developed and used to study rate constants for symmetric (resonant) and asymmetric charge exchange between potassium ion-atom pairs and between sodium ions and potassium atoms in the range of ionic energies from 0.1-2.0 eV. The results for symmetric charge exchange are in agreement with theory, but the rate constant for the

M. Riggin; M. Bloom

1975-01-01

192

Observation of Beam Loading in a Laser-Plasma Accelerator  

SciTech Connect

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

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

2009-11-06

193

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

SciTech Connect

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

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

2009-01-01

194

Influence of proton beam Coulomb explosion in laser proton acceleration  

NASA Astrophysics Data System (ADS)

To further understand proton acceleration driven by the interaction between ultra-intense laser pulse and foil targets, the influence of proton beam Coulomb explosion has been analyzed theoretically and investigated using two-dimensional particle-in-cell (2D-PIC) simulations. Employing different proton layer sizes in the simulations, it is found that proton beam Coulomb explosion plays an important role on proton acceleration, in particular on proton cut off energy. Proton dynamics including the effect of both sheath field and proton beam Coulomb explosion was proposed and discussed in detail. This work may serve to improve the understanding of proton acceleration driven by intense laser-foil interactions.

Yu, Jinqing; Jin, Xiaolin; Zhou, Weimin; Gu, Yuqiu; Zhan, Rongxin; Zhao, Zongqing; Cao, Leifeng; Li, Bin

2013-12-01

195

Self-accelerating self-trapped optical beams.  

PubMed

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

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

2011-05-27

196

Laser-and Beam-Driven Plasma Accelerators  

NASA Astrophysics Data System (ADS)

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

Joshi, Chandrashekhar

2006-10-01

197

Beam-beam effects investigation and parameters optimization for a circular e+e- collider at very high energies  

NASA Astrophysics Data System (ADS)

Several proposals exist for future circular electron-positron colliders designed for precise measurements of the Higgs boson characteristics and electroweak processes. At very high energies, synchrotron radiation of the particles in a strong electromagnetic field of the oncoming bunch (beamstrahlung) becomes extremely important, because of degradation of the beam lifetime and luminosity. We present theoretical calculations of beamstrahlung (including the beam lifetime reduction and the energy spread increase) which are benchmarked against quasi-strong-strong computer simulations. Calculation results are used to optimize TLEP (triple LEP) project (CERN).

Bogomyagkov, A.; Levichev, E.; Shatilov, D.

2014-04-01

198

Self-accelerating Airy Beams: Generation, Control, and Applications  

NASA Astrophysics Data System (ADS)

Recently, a specific type of nondiffracting beams named self-accelerating Airy beams has attracted a great deal of interest due to their unique properties and many proposed applications in areas such as optical micromanipulation, plasma guidance, vacuum electron acceleration, and routing surface plasmon polaritons. In contradistinction with Bessel beams, Airy beams do not rely on simple conical superposition of plane waves, and they possess the properties of self-acceleration in addition to nondiffraction and self-healing. For the past few years, tremendous research work has been devoted to the study of Airy beams, from theoretical predictions to experimental observations, from linear control to nonlinear self-trapping, and from fundamental aspects to demonstrations of potential applications. In this chapter, we provide an overview on generation and control of Airy beams and recent developments in the area.

Hu, Yi; Siviloglou, Georgios A.; Zhang, Peng; Efremidis, Nikolaos K.; Christodoulides, Demetrios N.; Chen, Zhigang

199

TIARA electrostatic accelerators for multiple ion beam application  

NASA Astrophysics Data System (ADS)

A unique electrostatic accelerators facility has been constructed mainly for application of multiple beam and microbeam to materials science research at JAERI Takasaki. The facility consists of a 3 MV single-ended accelerator with an extremely high voltage-stability of ± 1 × 10 -5, a 3 MV tandem accelerator and a 0.4 MV ion implanter, which cover various ion particles in an energy range of 10 keV to 20 MeV. A voltage ripple of ± 1 × 10 -5 (60 Vpp) at 3 MV has been achieved for the single-ended machine. The performance of accelerators, beam lines and their applications to various research activities are outlined.

Saitoh, Y.; Tajima, S.; Takada, I.; Mizuhashi, K.; Uno, S.; Ohkoshi, K.; Ishii, Y.; Kamiya, T.; Yotumoto, K.; Tanaka, R.; Iwamoto, E.

1994-05-01

200

Characterizing new physics with polarized beams at high-energy hadron colliders  

NASA Astrophysics Data System (ADS)

The TeV energy region is currently being explored by both the ATLAS and CMS experiments of the Large Hadron Collider and phenomena beyond the Standard Model are extensively searched for. Large fractions of the parameter space of many models have already been excluded, and the ranges covered by the searches will certainly be increased by the upcoming energy and luminosity upgrades. If new physics has to be discovered in the forthcoming years, the ultimate goal of the high-energy physics program will consist of fully characterizing the newly-discovered degrees of freedom in terms of properties such as their masses, spins and couplings. The scope of this paper is to show how the availability of polarized beams at high-energy proton-proton colliders could yield a unique discriminating power between different beyond the Standard Model scenarios. We first discuss in a model-independent way how this discriminating power arises from the differences between polarized and unpolarized parton distribution functions. We then demonstrate how polarized beams allow one not only to disentangle different production mechanisms giving the same final-state signature, but also to obtain information on the parameters of the hypothetical new physics sector of the theory. This is illustrated in the case of a particular class of scenarios leading to monotop production. We consider three specific models that could produce a monotop signature in unpolarized proton collisions, and show how they could be distinguished by means of single- and double-spin asymmetries in polarized collisions. Our results are presented for both the Large Hadron Collider operating at a center-of-mass energy of 14 TeV and a recently proposed Future Circular Collider assumed to collide protons at a center-of-mass energy of 100 TeV.

Fuks, Benjamin; Proudom, Josselin; Rojo, Juan; Schienbein, Ingo

2014-05-01

201

Cavity beam position monitor system for the Accelerator Test Facility 2  

NASA Astrophysics Data System (ADS)

The Accelerator Test Facility 2 (ATF2) is a scaled demonstrator system for final focus beam lines of linear high energy colliders. This paper describes the high resolution cavity beam position monitor (BPM) system, which is a part of the ATF2 diagnostics. Two types of cavity BPMs are used, C-band operating at 6.423 GHz, and S-band at 2.888 GHz with an increased beam aperture. The cavities, electronics, and digital processing are described. The resolution of the C-band system with attenuators was determined to be approximately 250 nm and 1?m for the S-band system. Without attenuation the best recorded C-band cavity resolution was 27 nm.

Kim, Y. I.; Ainsworth, R.; Aryshev, A.; Boogert, S. T.; Boorman, G.; Frisch, J.; Heo, A.; Honda, Y.; Hwang, W. H.; Huang, J. Y.; Kim, E.-S.; Kim, S. H.; Lyapin, A.; Naito, T.; May, J.; McCormick, D.; Mellor, R. E.; Molloy, S.; Nelson, J.; Park, S. J.; Park, Y. J.; Ross, M.; Shin, S.; Swinson, C.; Smith, T.; Terunuma, N.; Tauchi, T.; Urakawa, J.; White, G. R.

2012-04-01

202

Linear collider diagnostics  

NASA Astrophysics Data System (ADS)

Each major step towards higher energy particle accelerators relies on new technology. Linear colliders require beams of unprecedented brightness and stability. Instrumentation and control technology is the single most critical tool that enables linear colliders to extend our energy reach. In this paper we focus on the most challenging aspects of linear collider instrumentation systems. In the Next Linear Collider (NLC), high brightness multibunch e+/e- beams, with L+/-=1012 particles/pulse and ?x,y~50×5 ?m, originate in damping rings and are subsequently accelerated to several hundred GeV in 2 X-band 11424 MHz linacs from which they emerge with typical ?x,y~7×1 ?m. Following a high power collimation section the e+/e- beams are focused to ?x,y~300×5 nm at the interaction point. In this paper we will review the beam intensity, position and profile monitors (x, y, z), mechanical vibration sensing and stabilization systems, long baseline RF distribution systems and beam collimation hardware. .

Ross, Marc

2000-11-01

203

Stability of diaphragmed electron beams in a linear induction accelerator  

NASA Astrophysics Data System (ADS)

The effects of electromagnetic shielding of an electron beam by a series of metal diaphragms on transverse stability of beam motion are considered. The shielding coefficients are calculated for the quasistationary electric and magnetic fields of a beam displaced from the axis of the accelerator. The axial magnetic field strengths required for coherent beam focusing are calculated, and the growth rate of an unstable unsymmetric hybrid wave in the electron beam is found for a beam in a slow-wave structure formed by a series of diaphragms. It is shown that the destabilizing influence of the diaphragms can be reduced by increasing the period-to-radius ratio of the structure.

Aleksakhin, Iu. I.; Perelshtein, E. A.

1983-11-01

204

The LICPA accelerator of dense plasma and ion beams  

NASA Astrophysics Data System (ADS)

Laser-induced cavity pressure acceleration (LICPA) is a novel scheme of acceleration of dense matter having a potential to accelerate plasma projectiles with the energetic efficiency much higher than the achieved so far with other methods. In this scheme, a projectile placed in a cavity is irradiated by a laser beam introduced into the cavity through a hole and accelerated along a guiding channel by the thermal pressure created in the cavity by the laser-produced plasma or by the photon pressure of the ultraintense laser radiation trapped in the cavity. This paper summarizes briefly the main results of our recent LICPA studies, in particular, experimental investigations of ion beam generation and heavy macroparticle acceleration in the hydrodynamic LICPA regime (at moderate laser intensities ~ 1015W/cm2) and numerical, particle-in-cell (PIC) studies of production of ultraintense ion beams and fast macroparticles using the photon pressure LICPA regime (at high laser intensities > 1020 W/cm2). It is shown that in both LICPA regimes the macroparticles and ion beams can be accelerated much more efficiently than in other laser-based acceleration scheme commonly used and the accelerated plasma/ion bunches can have a wide variety of parameters. It creates a prospect for a broad range of applications of the LICPA accelerator, in particular in such domains as high energy density physics, ICF research (ion fast ignition, impact ignition) or nuclear physics.

Badziak, J.; Jablo?ski, S.; Pisarczyk, T.; Chodukowski, T.; Parys, P.; Raczka, P.; Rosi?ski, M.; Krousky, E.; Ullschmied, J.; Liska, R.; Kucharik, M.; Torrisi, L.

2014-04-01

205

Linear Beam-Beam Tune Shift Calculations for the Tevatron Collider.  

National Technical Information Service (NTIS)

A realistic estimate of the linear beam-beam tune shift is necessary for the selection of an optimum working point in the tune diagram. Estimates of the beam-beam tune shift using the ''Round Beam Approximation'' (RBA) have over estimated the tune shift f...

D. Johnson

1989-01-01

206

Multiple beam induction accelerators for heavy ion fusion  

NASA Astrophysics Data System (ADS)

Induction accelerators are appealing for heavy-ion driven inertial fusion energy (HIF) because of their high efficiency and their demonstrated capability to accelerate high beam current (?10 kA in some applications). For the HIF application, accomplishments and challenges are summarized. HIF research and development has demonstrated the production of single ion beams with the required emittance, current, and energy suitable for injection into an induction linear accelerator. Driver scale beams have been transported in quadrupole channels of the order of 10% of the number of quadrupoles of a driver. We review the design and operation of induction accelerators and the relevant aspects of their use as drivers for HIF. We describe intermediate research steps that would provide the basis for a heavy-ion research facility capable of heating matter to fusion relevant temperatures and densities, and also to test and demonstrate an accelerator architecture that scales well to a fusion power plant.

Seidl, Peter A.; Barnard, John J.; Faltens, Andris; Friedman, Alex; Waldron, William L.

2014-01-01

207

ISABELLE accelerator software, control system, and beam diagnostic philosophy  

SciTech Connect

The ISABELLE Project combines two large proton accelerators with two storage rings in the same facility using superconducting magnet technology. This combination leads to severe constraints on beam loss in magnets and involves complex treatment of magnetic field imperfections and correction elements. The consequent demands placed upon beam diagnostics, accelerator model programs, and the computer oriented control system are discussed in terms of an illustrative operation scenario.

Cornacchia, M.; Humphrey, J.W.; Niederer, J.; Poole, J.H.

1981-01-01

208

Beam dynamics in a long-pulse linear induction accelerator  

SciTech Connect

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

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

2010-01-01

209

Acceleration of ampere class H(-) ion beam by MeV accelerator.  

PubMed

The H(-) ion accelerator R&D to realize the international thermonuclear experimental reactor neutral beam is ongoing at Japan Atomic Energy Agency (JAEA). The required performance for the prototype MeV accelerator developed at JAEA is 1 MeV, 500 mA (current density of 200 A/m(2)) H(-) ion beam at the beamlet divergence angle of less than 7 mrad. Up to 2005, 836 keV, 146 A/m(2) H(-) ion beam was successfully accelerated as the highest record of the current density at MeV class energy beams. In the present work, high current negative ion beam acceleration test was performed by increasing the beam extraction apertures from 3 x 3 (9 apertures) to 3 x 5 (15 apertures). By fixing the air leak at the source chamber due to backstream ions as well as the improvement of voltage holding capability by a new fiber reinforced plastic insulator ring, the performance of the MeV accelerator was improved. So far, H(-) ion beam of 320 mA was successfully accelerated up to 796 keV with the beam divergence angle of 5.5 mrad. The accelerated drain current including the electron reaches close to the power supply limit for the MeV test facility. The heat flux by the backstream ion during the above beam acceleration was estimated to be 360 W/cm(2). The Cs leakage to the accelerator during the test campaign (Cs total input of 5.0 g) was 0.26 mg (7.0 microg/cm(2)). This is considered to be the allowable level from the viewpoint of voltage holding. PMID:18315236

Taniguchi, M; Inoue, T; Umeda, N; Kashiwagi, M; Watanabe, K; Tobari, H; Dairaku, M; Sakamoto, K

2008-02-01

210

Acceleration of ampere class H- ion beam by MeV accelerator  

NASA Astrophysics Data System (ADS)

The H- ion accelerator R&D to realize the international thermonuclear experimental reactor neutral beam is ongoing at Japan Atomic Energy Agency (JAEA). The required performance for the prototype MeV accelerator developed at JAEA is 1 MeV, 500 mA (current density of 200 A/m2) H- ion beam at the beamlet divergence angle of less than 7 mrad. Up to 2005, 836 keV, 146 A/m2 H- ion beam was successfully accelerated as the highest record of the current density at MeV class energy beams. In the present work, high current negative ion beam acceleration test was performed by increasing the beam extraction apertures from 3×3 (9 apertures) to 3×5 (15 apertures). By fixing the air leak at the source chamber due to backstream ions as well as the improvement of voltage holding capability by a new fiber reinforced plastic insulator ring, the performance of the MeV accelerator was improved. So far, H- ion beam of 320 mA was successfully accelerated up to 796 keV with the beam divergence angle of 5.5 mrad. The accelerated drain current including the electron reaches close to the power supply limit for the MeV test facility. The heat flux by the backstream ion during the above beam acceleration was estimated to be 360 W/cm2. The Cs leakage to the accelerator during the test campaign (Cs total input of 5.0 g) was 0.26 mg (7.0 ?g/cm2). This is considered to be the allowable level from the viewpoint of voltage holding.

Taniguchi, M.; Inoue, T.; Umeda, N.; Kashiwagi, M.; Watanabe, K.; Tobari, H.; Dairaku, M.; Sakamoto, K.

2008-02-01

211

Clean beams from laser wake-field accelerators via optical injection with a cleanup pulse  

NASA Astrophysics Data System (ADS)

Multiple colliding-pulse injection schemes have been proposed as means for trapping electrons in the ultrashort acceleration buckets of laser-generated wake fields. The primary goal of this paper is to present a parameter study to determine the beams that can be obtained through collisions of collinear laser pulses in uniform plasma. The parameter study is through fully self-consistent, two-dimensional, particle-in-cell simulations, as previous work used only test-particle computations. To remove the multiple beams that can commonly be generated in colliding pulse injection, we use a cleanup pulse, a trailing laser pulse that absorbs the wake. The wake then no longer exists in the region where the trailing beamlets would be, and so the trailing beamlets no longer form. A series of simulations predicts that with such one can obtain single, short (<=10 fs) beams with a bunch charge of order 10 pC, normalized emittance of order 2? ?m, and energy spread of the order of 10%. The parameters of the beams are insensitive to the amplitude of the backward pulse above normalized amplitudes of abw~0.4.

Cary, John R.; Giacone, R. E.; Nieter, C.; Bruhwiler, D. L.

2005-05-01

212

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOEpatents

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

Maschke, Alfred W. (East Moriches, NY)

1985-01-01

213

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOEpatents

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

Maschke, A.W.

1984-04-16

214

Physics of a Repetitively Pulsed 10 KAmp Electron Beam Accelerator.  

National Technical Information Service (NTIS)

Some aspects of physics that contributed to design and operation of the ETA 10 kAmp electron accelerator are discussed. These include: the electron source, the emittance growth in the injector, beam transport through the accelerator, and the influence of ...

T. J. Fessenden W. A. Atchison D. L. Birx R. J. Briggs J. C. Clark

1981-01-01

215

Beam Dynamics Issues of Muon Acceleration in RLA.  

National Technical Information Service (NTIS)

A conceptual design of a muon acceleration based on recirculating superconducting linacs is proposed. In the presented scenario, acceleration starts after ionization cooling at 210 MeV/c and proceeds to 20 GeV, where the beam is injected into a neutrino f...

S. A. Bogacz

2005-01-01

216

The Neutral Particle Beam Space Experiment (NPBSE) accelerator designs  

Microsoft Academic Search

Accelerators that are designed to operate in a space environment are more strongly constrained by hardware envelope size, power consumption and cooling requirements than are equivalent ground based systems. The challenges presented by these constraints have resulted in the development of novel features in the Neutral Particle Beam Space Experiment (NPBSE) accelerator designs, which may also find application in ground

C. C. Paulson; A. M. M. Todd; S. L. Mendelsohn

1993-01-01

217

The next linear collider test accelerator{close_quote}s RF pulse compression and transmission systems  

SciTech Connect

The overmoded rf transmission and pulsed power compression system for SLAC{close_quote}s Next Linear Collider (NLC) program requires a high degree of transmission efficiency and mode purity to be economically feasible. To this end, a number of new, high power components and systems have been developed at X-band, which transmit rf power in the low loss, circular TE{sub 01} mode with negligible mode conversion. In addition, a highly efficient SLED-II [1] pulse compressor has been developed and successfully tested at high power at two accelerator test facilities at SLAC. The systems produced a 200 MW pulse with a near-perfect flat-top with pulse widths ranging from 150{endash}245 ns. In this paper we describe the design and test results of a rectangular-to-circular mode converter and the components/transmission systems based on them, as well as the design and measurements of the high power pulse compression systems using SLED-II. We will also describe how these components are being used to efficiently provide high power rf in the NLC Test Accelerator (NLCTA) program at SLAC. {copyright} {ital 1997 American Institute of Physics.}

Tantawi, S.G.; Vlieks, A.E.; Fant, K.; Lavine, T.; Loewen, R.J.; Pearson, C.; Pope, R.; Rifkin, J.; Ruth, R.D. [Stanford Linear Accelerator Center, 2575 Sand Hill Rd., Menlo Park, California, 94025 (United States)

1997-03-01

218

Ablative Rayleigh-Taylor and Richtmyer-Meshkov Instabilities in Laser-Accelerated Colliding Foils  

NASA Astrophysics Data System (ADS)

In our experiments done on the Nike KrF laser, we study instability growth at shock-decelerated interfaces in planar colliding-foil experiments. We use streaked monochromatic (1.86 keV) x-ray face-on imaging diagnostics to measure the areal mass modulation growth caused by the instability. Higher x-ray energies up to 5.25 keV are used to follow the shock propagation as well as the 1D dynamics of the collision. While a laser-driven foil is accelerated towards the stationary low-density foam layer, an ablative RT instability develops. Having reached a high velocity, the foil hits the foam layer. The impact generates strong shocks in the plastic and in the foam. The reflected shock wave re-shocks the ablation front, its acceleration stops, and so does the observed RT growth. This is followed by areal mass oscillations due to the ablative RM instability and feedout mechanisms, of which the latter dominates.

Aglitskiy, Y.; Metzler, N.; Karasik, M.; Serlin, V.; Weaver, J.; Obenschain, S. P.; Oh, J.; Schmitt, A. J.; Velikovich, A. L.; Zalesak, S. T.; Gardner, J. H.; Harding, E. C.

2008-11-01

219

The next linear collider test accelerator's RF pulse compression and transmission systems  

NASA Astrophysics Data System (ADS)

The overmoded rf transmission and pulsed power compression system for SLAC's Next Linear Collider (NLC) program requires a high degree of transmission efficiency and mode purity to be economically feasible. To this end, a number of new, high power components and systems have been developed at X-band, which transmit rf power in the low loss, circular TE01 mode with negligible mode conversion. In addition, a highly efficient SLED-II [1] pulse compressor has been developed and successfully tested at high power at two accelerator test facilities at SLAC. The systems produced a 200 MW pulse with a near-perfect flat-top with pulse widths ranging from 150-245 ns. In this paper we describe the design and test results of a rectangular-to-circular mode converter and the components/transmission systems based on them, as well as the design and measurements of the high power pulse compression systems using SLED-II. We will also describe how these components are being used to efficiently provide high power rf in the NLC Test Accelerator (NLCTA) program at SLAC.

Tantawi, S. G.; Vlieks, A. E.; Fant, K.; Lavine, T.; Loewen, R. J.; Pearson, C.; Pope, R.; Rifkin, J.; Ruth, R. D.

1997-03-01

220

Beam trapping in the NRL modified betatron accelerator. Interim report  

SciTech Connect

The experimental results on the trapping of the beam NRL modified betatron accelerator are in good agreement with a revised model of resistive trapping and thus it may be concluded that the wall resistivity is responsible for the inward spiral motion of the beam after injection.

Kapetanakos, C.A.; Dialetis, D.; Marsh, S.J.; Len, K.L.; Smith, T.

1991-05-15

221

Induction Accelerator Technology Choices for the Integrated Beam Experiment (IBX)  

SciTech Connect

Over the next three years the research program of the Heavy Ion Fusion Virtual National Laboratory (HIF-VNL), a collaboration among LBNL, LLNL, and PPPL, is focused on separate scientific experiments in the injection, transport and focusing of intense heavy ion beams at currents from 100 mA to 1 A. As a next major step in the HIF-VNL program, we aim for a complete 'source-to-target' experiment, the Integrated Beam Experiment (IBX). By combining the experience gained in the current separate beam experiments IBX would allow the integrated scientific study of the evolution of a single heavy ion beam at high current ({approx}1 A) through all sections of a possible heavy ion fusion accelerator: the injection, acceleration, compression, and beam focusing.This paper describes the main parameters and technology choices of the planned IBX experiment. IBX will accelerate singly charged potassium or argon ion beams up to 10 MeV final energy and a longitudinal beam compression ratio of 10, resulting in a beam current at target of more than 10 Amperes. Different accelerator cell design options are described in detail: Induction cores incorporating either room temperature pulsed focusing-magnets or superconducting magnets.

Leitner, M.A. [Ernest Orlando Lawrence Berkeley National Laboratory (United States); Celata, C.M. [Ernest Orlando Lawrence Berkeley National Laboratory (United States); Lee, E.P. [Ernest Orlando Lawrence Berkeley National Laboratory (United States); Logan, B.G. [Ernest Orlando Lawrence Berkeley National Laboratory (United States); Sabbi, G. [Ernest Orlando Lawrence Berkeley National Laboratory (United States); Waldron, W.L. [Ernest Orlando Lawrence Berkeley National Laboratory (United States); Barnard, J.J. [Lawrence Livermore National Laboratory (United States)

2003-09-15

222

Design of an 18 MW vortex flow water beam dump for 500 GeV electrons/positrons of an international linear collider  

NASA Astrophysics Data System (ADS)

Beam dumps are essential components of any accelerator system. They are usually located at the end of the beam delivery systems and are designed to safely absorb and dissipate the particle energy. In the second stage of the proposed International Linear Collider (ILC), the electron and positron beams are accelerated to 500 GeV each (1 TeV total). Each bunch will have 2×1010 electrons/positrons, and 2820 bunches form one beam bunch train with time duration of 0.95 ms and 4 Hz frequency. The average beam power will be 18 MW with a peak power of 4.5 GW. The FLUKA code was used to determine the power deposited by the beam at all critical locations. This data forms the input into the thermal hydraulic analysis CFD code for detailed flow and thermal evaluation. Both 2D and 3D flow analyses were carried out at all the critical regions to arrive at optimum geometry and flow parameters of the beam dump. The generation and propagation of pressure waves due to rapid deposition of heat has also been analyzed.

Satyamurthy, Polepalle; Rai, Pravin; Tiwari, Vikas; Kulkarni, Kiran; Amann, John; Arnold, Raymond G.; Walz, Dieter; Seryi, Andrei; Davenne, Tristan; Caretta, Ottone; Densham, Chris; Appleby, Robert B.

2012-07-01

223

Beam losses and beam halos in accelerators for new energy sources  

SciTech Connect

Large particle accelerators are proposed as drivers for new ways to produce electricity from nuclear fusion and fission reactions. The accelerators must be designed to deliver large particle beam currents to a target facility with very little beam spill along the accelerator itself, in order that accelerator maintenance can be accomplished without remote manipulators. Typically, particle loss is preceded by the formation of a tenuous halo of particles around the central beam core, caused by beam dynamics effects, often coupled with the slight imperfections inevitable in a practical design. If the halo becomes large enough, particles may be scraped off along the accelerator. The tolerance for beam spill in different applications is discussed, halo mechanisms and recent work to explore and understand their dynamics are reviewed, and possible directions for future investigation are outlined. 17 refs., 10 figs.

Jameson, R.A.

1995-12-31

224

Production of accelerating quad Airy beams and their optical characteristics.  

PubMed

Based on a geometric caustic argument and diffraction catastrophe theory, we generate a novel form of accelerating beams using a symmetric 3/2 phase-only pattern. Such beams can be called accelerating quad Airy beams (AQABs) because they look very much like four face-to-face combined Airy beams. Optical characteristics of AQABs are subsequently investigated. The research results show that the beams have axial-symmetrical and centrosymmetrical transverse intensity patterns and quasi-diffraction-free propagation features for their four main lobes while undergoing transverse shift along parabolic trajectories. Moreover, we also demonstrate that AQABs possess self-construction ability when local areas are blocked. The unique optical properties of these beams will make them useful tools for future scientific applications. PMID:24977608

Ren, Zhijun; Wu, Qiong; Shi, Yile; Chen, Chen; Wu, Jiangmiao; Wang, Hui

2014-06-16

225

High transformer ratio drive beams for wakefield accelerator studies  

NASA Astrophysics Data System (ADS)

For wakefield based acceleration schemes, use of an asymmetric (or linearly ramped) drive bunch current profile has been predicted to enhance the transformer ratio and generate large accelerating wakes. We discuss plans and initial results for producing such bunches using the 20 to 23 GeV electron beam at the FACET facility at SLAC National Accelerator Laboratory and sending them through plasmas and dielectric tubes to generate transformer ratios greater than 2 (the limit for symmetric bunches). The scheme proposed utilizes the final FACET chicane compressor and transverse collimation to shape the longitudinal phase space of the beam.

England, R. J.; Ng, C.-K.; Frederico, J.; Hogan, M. J.; Litos, M.; Muggli, P.; Joshi, C.; An, W.; Andonian, G.; Mori, W.; Lu, W.

2012-12-01

226

High transformer ratio drive beams for wakefield accelerator studies  

SciTech Connect

For wakefield based acceleration schemes, use of an asymmetric (or linearly ramped) drive bunch current profile has been predicted to enhance the transformer ratio and generate large accelerating wakes. We discuss plans and initial results for producing such bunches using the 20 to 23 GeV electron beam at the FACET facility at SLAC National Accelerator Laboratory and sending them through plasmas and dielectric tubes to generate transformer ratios greater than 2 (the limit for symmetric bunches). The scheme proposed utilizes the final FACET chicane compressor and transverse collimation to shape the longitudinal phase space of the beam.

England, R. J.; Ng, C.-K.; Frederico, J.; Hogan, M. J.; Litos, M.; Muggli, P.; Joshi, C.; An, W.; Andonian, G.; Mori, W.; Lu, W. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Max Planck Institute for Physics, 80805 Munich (Germany); University of California Los Angeles, Los Angeles, CA 90095 (United States); Tsinghua University, Beijing (China)

2012-12-21

227

Ion bunch length effects on the beam-beam interaction and its compensation in a high-luminosity ring-ring electron-ion collider  

SciTech Connect

One of the luminosity limits in a ring-ring electron-ion collider is the beam-beam effect on the electrons. In the limit of short ion bunches, simulation studies have shown that this limit can be significantly increased by head-on beam-beam compensation with an electron lens. However, with an ion bunch length comparable to the beta-function at the IP in conjunction with a large beam-beam parameter, the electrons perform a sizeable fraction of a betatron oscillation period inside the long ion bunches. We present recent simulation results on the compensation of this beam-beam interaction with multiple electron lenses.

Montag C.; Oeftiger, A.; Fischer, W.

2012-05-20

228

Linear Collider Physics Resource Book for Snowmass 2001 - Part 4: Theoretical, Accelerator, and Experimental Options  

Microsoft Academic Search

This Resource Book reviews the physics opportunities of a next-generation e+e- linear collider and discusses options for the experimental program. Part 4 discusses options for the linear collider program, at a number of levels. First, it presents a broad review of physics beyond the Standard Model, indicating how the linear collider is relevant to each possible pathway. Next, it surveys

T. Abe

2001-01-01

229

Design study of primary ion provider for relativistic heavy ion collider electron beam ion source  

NASA Astrophysics Data System (ADS)

Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented.

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

2010-02-01

230

Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.  

PubMed

Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented. PMID:20192366

Kondo, K; Kanesue, T; Tamura, J; Okamura, M

2010-02-01

231

Mechanisms and control of beam halo formation in intense microwave sources and accelerators  

NASA Astrophysics Data System (ADS)

Halo formation and control in space-charge-dominated electron and ion beams are investigated in parameter regimes relevant to the development of high-power microwave (HPM) sources and high-intensity electron and ion linear accelerators. In particular, a mechanism for electron beam halo formation is identified in high-power periodic permanent magnet (PPM) focusing klystron amplifiers. It is found in self-consistent simulations that large-amplitude current oscillations induce mismatched beam envelope oscillations and electron beam halo formation. Qualitative agreement is found between simulations and the 50 MW 11.4 GHz PPM focusing klystron experiment at Stanford Linear Accelerator Center (SLAC) (D. Sprehn, G. Caryotakis, E. Jongewaard, and R. M. Phillips, ``Periodic permanent magnetic development for linear collider X-band klystrons,'' Proceedings of the XIXth International Linac Conference, Argonne National Laboratory Report ANL-98/28, 1998, p. 689). Moreover, a new class of cold-fluid corkscrewing elliptic beam equilibria is discovered for ultrahigh-brightness, space-charge dominated electron or ion beam propagation through a linear focusing channel consisting of uniform solenoidal magnetic focusing fields, periodic solenoidal magnetic focusing fields, and/or alternating-gradient quadrupole magnetic focusing fields in an arbitrary arrangement including field tapering. As an important application of such new cold-fluid corkscrewing elliptic beam equilibria, a technique is developed and demonstrated for controlling of halo formation and beam hollowing in a rms-matched ultrahigh-brightness ion beam as it is injected from an axisymmetric Pierce diode into an alternating-gradient magnetic quadrupole focusing channel.

Chen, C.; Pakter, R.

2000-05-01

232

Muon colliders  

SciTech Connect

Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity {mu}{sup +}{mu}{sup {minus}} colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Problems of detector background are also discussed. {copyright} {ital 1996 American Institute of Physics.}

Palmer, R.B. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)]|[Stanford Linear Accelerator Center, Stanford, California 94309 (United States); Sessler, A. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Skrinsky, A. [BINP, RU-630090 Novosibirsk (Russia); Tollestrup, A. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Baltz, A.J. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Chen, P. [Stanford Linear Accelerator Center, Stanford, California 94309 (United States); Cheng, W. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Cho, Y. [Argonne National Laboratory, Argonne, Illinois 60439-4815 (United States); Courant, E. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Fernow, R.C. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Gallardo, J.C. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Garren, A. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)]|[UCLA, Los Angeles, California 90024-1547 (United States); Green, M. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kahn, S.; Kirk, H.; Lee, Y.Y. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Mills, F.; Mokhov, N. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Morgan, G. [Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Neuffer, D. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)]|[CEBAF, Newport, News, Virginia 23606 (United States); Noble, R. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Norem, J. [Argonne National Laboratory, Argonne, Illinois 60439-4815 (United States); Popovic, M.

1996-05-01

233

Muon Colliders  

SciTech Connect

Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity {mu}{sup +}{mu}{sup -} colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Problems of detector background are also discussed.

Robert B. Palmer; A. Sessler; A. Skrinsky; A. Tollestrup; A.J. Baltz; P. Chen; W-H. Cheng; Y. Cho; E. Courant; Richard C. Fernow; Juan C. Gallardo; A. Garren; M. Green; S. Kahn; H. Kirk; Y. Y. Lee; F. Mills; N. Mokhov; G. Morgan; David Neuffer; R. Noble; J. Norem; M. Popovic; L. Schachinger; G. Silvestrov; D. Summers; I. Stumer; M. Syphers; Yagmur Torun; D. Trbojevic; W. Turner; A. Van Ginneken; T. Vsevolozhskaya; R. Weggel; E. Willen; David Winn; J. Wurtele

1994-11-01

234

GPU accelerated online multi-particle beam dynamics simulator for ion linear particle accelerators  

NASA Astrophysics Data System (ADS)

An online beam dynamics simulator is being developed for use in the operation of an ion linear particle accelerator. By employing Graphics Processing Unit (GPU) technology, the performance of the simulator has been significantly increased over that of a single CPU and is therefore viable in the demanding accelerator operations environment. Once connected to the accelerator control system, it can rapidly respond to any control set point changes and predict beam properties along an ion linear accelerator in pseudo-real time. This simulator will be a virtual beam diagnostic tool which is especially useful when direct beam measurements are not available. Details about the code structure design, physics algorithms, GPU implementations, and performance are presented.

Pang, X.; Rybarcyk, L.

2014-03-01

235

Transformer ratio improvement for beam based plasma accelerators  

SciTech Connect

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

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

2012-12-21

236

Transformer ratio improvement for beam based plasma accelerators  

NASA Astrophysics Data System (ADS)

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

O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl

2012-12-01

237

The propagation distance of the by-product ion beams emitted from neutral particle beam accelerators  

SciTech Connect

The effects of collective electric fields on the propagation of the positive-ion and negative-ion by-products from neutral particle beam accelerators are examined. For present and future space-based neutral particle beam experiments, it is shown that the by-product beams do not propagate across the earth's magnetic field. 4 refs., 3 figs.

Borovsky, J.E.

1989-11-01

238

The propagation distance of the by-product ion beams emitted from neutral particle beam accelerators  

Microsoft Academic Search

The effects of collective electric fields on the propagation of the positive-ion and negative-ion by-products from neutral particle beam accelerators are examined. For present and future space-based neutral particle beam experiments, it is shown that the by-product beams do not propagate across the earth's magnetic field. 4 refs., 3 figs.

Borovsky

1989-01-01

239

Wideband precision current transformer for the magnet current of the beam extraction kicker magnet of the large hadron collider  

Microsoft Academic Search

The LHC beam extraction system is composed of 15 fast kicker magnets per beam to extract the particles in one turn of the collider and to safely dispose them on external absorbers. Each magnet is powered by a separate pulse generator. The generator produces a magnet current pulse with 3 us rise time, 20 kA amplitude and 1.8 ms fall

E. Vossenberg; G. Grawer

2004-01-01

240

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

NASA Astrophysics Data System (ADS)

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

Simakov, Evgenya I.; Carlsten, Bruce E.; Shchegolkov, Dmitry Yu.

2012-12-01

241

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

SciTech Connect

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

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

2010-02-15

242

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

SciTech Connect

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

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

2012-12-21

243

Long-pulse beam acceleration of MeV-class H(-) ion beams for ITER NB accelerator.  

PubMed

In order to realize neutral beam systems in International Thermonuclear Experimental Reactor whose target is to produce a 1 MeV, 200 A/m(2) during 3600 s D(-) ion beam, the electrostatic five-stages negative ion accelerator so-called "MeV accelerator" has been developed at Japan Atomic Energy Agency. To extend pulse length, heat load of the acceleration grids was reduced by controlling the ion beam trajectory. Namely, the beam deflection due to the residual magnetic field of filter magnet was suppressed with the newly developed extractor with a 0.5 mm off-set aperture displacement. The new extractor improved the deflection angle from 6 mrad to 1 mrad, resulting in the reduction of direct interception of negative ions from 23% to 15% of the total acceleration power, respectively. As a result, the pulse length of 130 A/m(2), 881 keV H(-) ion beam has been successfully extended from a previous value of 0.4 s to 8.7 s. This is the first long pulse negative ion beam acceleration over 100 MW/m(2). PMID:24593581

Umeda, N; Kashiwagi, M; Taniguchi, M; Tobari, H; Watanabe, K; Dairaku, M; Yamanaka, H; Inoue, T; Kojima, A; Hanada, M

2014-02-01

244

Error-induced beam degradation in Fermilab's accelerators  

NASA Astrophysics Data System (ADS)

In Part I, three independent models of Fermilab's Booster synchrotron are presented. All three models are constructed to investigate and to explore the effects of unavoidable machine errors on a proton beam under the influence of space-charge effects. The first is a stochastic noise model. Electric current fluctuations arising from power supplies are ubiquitous and unavoidable and are a source of instabilities in accelerators of all types. A new noise module for generating the Ornstein-Uhlenbeck (O-U) stochastic noise is first created and incorporated into the existing Object-oriented Ring Beam Injection and Tracking (ORBIT-FNAL) package. After being convinced that the noise does matter to a beam with a preliminary model, we proceed to measure directly current ripples and common-mode voltages from all four Gradient Magnet Power Supplies (GMPS). Then, the current signals are Fourier-analyzed. Based upon the power spectra of current signals, we tune up the Ornstein-Uhlnbeck noise model. As a result, we are able to closely match the frequency spectra between current measurements and the modeled O-U stochastic noise. The stochastic noise modeled upon measurements is applied to the Booster beam in the presence of the full space-charge effects. This noise model, accompanied by a suite of beam diagnostic calculations, manifests that the stochastic noise, impinging upon the beam and coupled to the space-charge effects, can substantially enhance the beam degradation process throughout the injection period. The second model is a magnet misalignment model. It is the first time to utilize the latest beamline survey data for building a magnet-by-magnet misalignment model. Given as-found survey fiducial coordinates, we calculate all types of magnet alignment errors (station error, pitch, yaw, roll, twists, etc.) are implemented in the model. We then follow up with statistical analysis to understand how each type of alignment errors are currently distributed around the Booster ring. The ORBIT-FNAL simulations with space charge included show that rolled magnets, in particular, have substantial effects on the Booster beam. This survey-data-based misalignment model can predict how much improvement in machine performance can be achieved if prioritized or selected realignment work is done. In other words, this model can help us investigate different realignment scenarios for the Booster. In addition, by calculating average angular kicks from all misaligned magnets, we expect this misalignment model to serve as guidelines for resetting the strengths of corrector magnets. The third model for the Booster is a time-structured multi-turn injection model. Microbunch-injection scenarios with different time structures are explored in the presence of longitudinal space-charge force. Due to the radio-frequency (RF) bucket mismatch between the Booster and the 400-MeV transferline, RF-phase offsets can be parasitically introduced during the injection process. Using the microbunch multi-turn injection, we carry out ESME-ORBIT combined simulations. This combined simulation allows us to investigate realistic charge-density distribution under full space-charge effects. The growth rates of transverse emittances turned out to be 20% in both planes. This microbunch-injection scenarios is also applicable to the future 8-GeV Superconducting Linac Proton Driver and the upgraded Main Injector at Fermilab. In Part II, the feasibility of momentum-stacking method of proton beams is investigated. When the Run2 collider program at Fermilab is terminated around year 2009, the present antiproton source can be available for other purposes. One possible application is to convert the antiproton accumulator to a proton accumulator, so that the beam power from the Main Injector could be enhanced by a factor of four. Through adiabatic processes and optimized parameters of synchrotron motion, we demonstrate with an aid of the ESME code that up to four proton batches can be stacked in the momentum acceptance available for the Accumulator ring. This momentum-stacking method is e

Yong, Sung-Yong Phil

245

High-energy high-luminosity ?+?- collider design  

Microsoft Academic Search

We discuss the design of a high luminosity (1035 cm-2 s-1), high energy (2+2 TeV) ?+?- collider, starting from the proton accelerator needed to generate the muon beams and proceeding through the muon storage ring

Robert B. Palmer; Richard Fernow; Juan C. Gallardo; Y. Y. Lee; Yagmur Torun; D. Neuffer; David Winn

1995-01-01

246

Data handling facility for the Sandia Particle Beam Fusion Accelerator  

SciTech Connect

This paper describes an on-line data handling facility for Sandia's Particle Beam Fusion Accelerator, PBFA-I, and the upgrade prototype machine Supermite. These accelerators are used for research on inertial confinement fusion (ICF) using particle beams. The main objectives in designing the data acquisition system were: (1) process both experiment and machine performance diagnostic signals, (2) record high signal-to-noise ratio, wideband waveforms in a severe EMP environment, (3) support multiple users recording and analyzing data simultaneously, and (4) provide fast turnaround for experimental results. Commercially available equipment is used wherever possible. However, several special purpose devices were developed. This data handling facility is a significant upgrade of an existing system that supports other Sandia particle beam fusion research accelerators.

Boyer, W. B.; Neau, E. L.

1980-01-01

247

Beam acceleration in plasma focus device  

Microsoft Academic Search

The proton beam emission from the small 8kJ plasma focus device operated with the H2 filling was analyzed. Maximum energy and yield were obtained using NTD. The fast protons were registered with the energy up to 500keV using the polycarbonate absorbers with the different thickness.

R. Antanasijevi?; R. Banjanac; A. Dragi?; Z. Mari?; J. Stanojevi?; V. Udovi?i?; J. Vukovi?

2001-01-01

248

A microsecond-pulsewidth, intense, light-ion beam accelerator  

SciTech Connect

A relatively long-pulsewidth (0.1-1 {mu}s) intense ion beam accelerator has been built for materials processing applications. An applied-B{sub r}, magnetically-insulated extraction ion diode with dielectric flashover ion source is installed directly onto the output of a 1.2-MV, 300-kJ Marx generator. Initial operation of the accelerator at 0.4 MV indicates satisfactory performance without the need for additional pulse-shaping.

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

1993-07-01

249

Beam dynamics simulation of the Spallation Neutron Source linear accelerator  

Microsoft Academic Search

The accelerating structure for Spallation Neutron Source (SNS) consists of a radio-frequency-quadrupole-linac (RFQ), a drift-tube-linac (DTL), a coupled-cavity-drift-tube-linac (CCDTL), and a coupled-cavity-linac (CCL). The linac is operated at room temperature. The authors discuss the detailed design of linac which accelerates an H⁻ pulsed beam coming out from RFQ at 2.5 MeV to 1000 MeV. They show a detailed transition from

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

1998-01-01

250

Recent beam development for nuclear science at the MIT-bates linear accelerator center  

NASA Astrophysics Data System (ADS)

During the past two years, two sets of high priority nuclear physics experiments, SAMPLE, and part of the Out of Plane Spectrometer (OOPS) program have been completed at the MIT-Bates Laboratory. Good progress is also being made on the next major program, the Bates Large Acceptance Spectrometer Toroid (BLAST). Research and technical innovations pursued on the accelerator complex to accomplish these experiments have established new beam delivery capabilities for nuclear science. The centerpiece of the accelerator facility is the 190 m stretcher and storage South Hall Ring (SHR). The significant new achievements are the availability of highly polarized stored or extracted electron beams, and spin manipulation capability. With a 180° Siberian Snake spin rotator, over 120 mA of polarized beam has been stored at 670 MeV. There was no evidence of depolarization during a beam storage time of one hour. A prototype of a fast spin flipper, to achieve polarization reversal of the stored beam, was tested, with about 85% spin flip efficiency. A future development will be the upgrade of the stored beam energy. A low emittance lattice, required to increase the quantum lifetime above 1 GeV, will be implemented prior to the next BLAST run, scheduled for early 2002. The energy range, the uniquely flexible ring lattice structure, and the single 180° spin rotator, make the South Hall Ring an ideal tool for spin dynamics studies. Of particular interest is the mechanism for fast self-polarization enhanced by wigglers, to achieve high equilibrium polarization. This is essential for a ring-ring option for the Electron Ion Collider (EIC) project, proposed by Bates in collaboration with the Budker Institute of Nuclear Physics in Novosibirsk. Details of research and innovations on the polarized electron source, polarized beam handling, and the ring are presented. .

Wang, Fuhua; Farkhondeh, Manouchehr; Franklin, Wilbur A.; Jacobs, Kenneth D.; van der Laan, Jan B.; Tschalaer, Christoph; Zwart, G. Townsend

2002-04-01

251

Laser-driven shock acceleration of monoenergetic ion beams.  

PubMed

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

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

2012-11-21

252

Laser-Driven Shock Acceleration of Monoenergetic Ion Beams  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

253

Iron beam acceleration using direct plasma injection schemea)  

NASA Astrophysics Data System (ADS)

A new set of vanes of radio frequency quadrupole (RFQ) accelerator was commissioned using highly charged iron beam. To supply high intensity heavy ion beams to the RFQ, direct plasma injection scheme (DPIS) with a confinement solenoid was adopted. One of the difficulties to utilize the combination of DPIS and a solenoid field is a complexity of electro magnetic field at the beam extraction region, since biasing high static electric field for ion extraction, RFQ focusing field, and the solenoid magnetic field fill the same space simultaneously. To mitigate the complexity, a newly designed magnetic field clamps were used. The intense iron beam was observed with bunched structure and the total accelerated current reached 2.5 nC.

Okamura, M.; Kanesue, T.; Yamamoto, T.; Fuwa, Y.

2014-02-01

254

Polymeric flocculants processing by accelerated electron beams and microwave heating  

NASA Astrophysics Data System (ADS)

Results obtained by accelerated electron beam, microwave and simultaneous microwave and electron beam application in the chemistry of acrylamide and acrylic acid copolymers (polymeric flocculants used for wastewater treatment) are presented. Comparative results concerning the molecular weight and Huggins' constant for the acrylamide and acrylic acid copolymers obtained by classical heating, microwave heating, electron beam irradiation and simultaneous microwave and electron beam treatment are reported. Microwave heating produces high water solubility of the polymeric flocculants but median molecular weight values. Electron beam irradiation gives high molecular weight values but associated with a cross-linked structure (poor water solubility) while microwave energy addition to electron beam energy gives simultaneously high molecular weight values and high water solubility.

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

2002-08-01

255

Environmental radiation effects from muon and tau colliders and their impact on facility licensing.  

PubMed

Although contemporary accelerators only affect their local radiation environment, muon and tau colliders produce radiation profiles that extend far beyond their site boundaries. These radiation profiles affect the licensing and siting of these planned accelerators. The analysis presented herein suggests that a linear collider concept with the lepton beams collided in air offers a means to limit the environmental radiation effects from these accelerators. PMID:22721942

Bevelacqua, J J

2012-11-01

256

A gas cluster ion beam accelerator  

Microsoft Academic Search

An assembled CO2 gas cluster ion beam system was assessed using a retarding field analyzer and a time-of-flight mass spectrometer. The CO2 gas was expanded to form gas clusters at the input pressure of 1–5 bar through a quartz Laval nozzle. At 4 bar, it is confirmed that the clusters consisted of about 500 molecules. Also the dependence of the

Jae-Hoon Song; Duck-Kyun Choi; Won-Kook Choi

2001-01-01

257

The Next Linear Collider machine protection system  

Microsoft Academic Search

The Next Linear Collider (NLC) electron and positron beams are capable of damaging the linac accelerating structure and beamline vacuum chambers during an individual aberrant accelerator pulse. Machine protection system (MPS) considerations, outlined in this paper for the 1 TeV NLC design, have an impact on the engineering and design of most machine components downstream of the damping ring injector

C. Adolphsen; J. Frisch; R. K. Jobe; D. McCormick; W. R. Nelson; T. O. Raubenheimer; S. Rokni; M. C. Ross; P. Tenenbaum; D. R. Walz

1999-01-01

258

Heavy ion beam acceleration in the KEK digital accelerator: Induction acceleration from 200 keV to a few tens of MeV  

NASA Astrophysics Data System (ADS)

The procedure for induction acceleration of a heavy ion beam of A/Q=4 in the KEK digital accelerator is reported. This paper discusses essential issues associated with induction acceleration of ion beams from low energies, including injection error, relatively large closed orbit distortion, and a fully predictive control method for the acceleration.

Yoshimoto, T.; Barata, M.; Iwashita, T.; Harada, S.; Arakawa, D.; Arai, T.; Liu, X.; Adachi, T.; Asao, H.; Kadokura, E.; Kawakubo, T.; Kubo, T.; Leo, K. W.; Nakanishi, H.; Okada, Y.; Okamura, K.; Okazaki, K.; Someya, H.; Takayama, K.; Wake, M.

2014-01-01

259

Fully vectorial accelerating diffraction-free Helmholtz beams.  

PubMed

We show that new families of diffraction-free nonparaxial accelerating optical beams can be generated by considering the symmetries of the underlying vectorial Helmholtz equation. Both two-dimensional transverse electric and magnetic accelerating wave fronts are possible, capable of moving along elliptic trajectories. Experimental results corroborate these predictions when these waves are launched from either the major or minor axis of the ellipse. In addition, three-dimensional spherical nondiffracting field configurations are presented along with their evolution dynamics. Finally, fully vectorial self-similar accelerating optical wave solutions are obtained via oblate-prolate spheroidal wave functions. In all occasions, these effects are illustrated via pertinent examples. PMID:23215489

Aleahmad, Parinaz; Miri, Mohammad-Ali; Mills, Matthew S; Kaminer, Ido; Segev, Mordechai; Christodoulides, Demetrios N

2012-11-16

260

Beam centroid and envelope model for the SLIA accelerator  

NASA Astrophysics Data System (ADS)

The RAM computer code has been developed to model the Spiral Line Induction Accelerator (SLIA), which is under development at Pulse Sciences Inc. (PSI). The code advances the beam centroid and envelope equations for a complete current pulse in this high-current recirculating accelerator. Since the beam cross-section is elliptical, in general, and the transverse x-y motions are coupled via an axial magnetic field, the beam envelope is modeled using a 4 × 4 covariance matrix. The envelope equation includes a correction for beam diamagnetism. Toroidal self-field contributions to the bending field and the transverse frequencies have been calculated; the results retain terms which were inconsistently omitted in previous derivations, leading to incorrect frequencies. The code uses a circuit model to compute the beam-loading effect on the accelerating voltage at each gap. The transverse gap forces, which drive the beam breakup (BBU) instability are also computed. Realistic field maps for all beamline elements (solenoids, stellarator coils, bending fields, and matching quadrupoles) are incorporated.

Hughes, Thomas P.; Genoni, Thomas C.

1996-05-01

261

Accelerators for the PS neutrino beam  

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

262

Performance Modeling and Optimization of a High Energy CollidingBeam Simulation Code  

SciTech Connect

An accurate modeling of the beam-beam interaction is essential to maximizing the luminosity in existing and future colliders. BeamBeam3D was the first parallel code that can be used to study this interaction fully self-consistently on high-performance computing platforms. Various all-to-all personalized communication (AAPC) algorithms dominate its communication patterns, for which we developed a sequence of performance models using a series of micro-benchmarks. We find that for SMP based systems the most important performance constraint is node-adapter contention, while for 3D-Torus topologies good performance models are not possible without considering link contention. The best average model prediction error is very low on SMP based systems with of 3% to 7%. On torus based systems errors of 29% are higher but optimized performance can again be predicted within 8% in some cases. These excellent results across five different systems indicate that this methodology for performance modeling can be applied to a large class of algorithms.

Shan, Hongzhang; Strohmaier, Erich; Qiang, Ji; Bailey, David H.; Yelick, Kathy

2006-06-01

263

Working group summary: Machine design for the {mu}{sup +}{minus}{mu}{sup {minus}} collider  

SciTech Connect

We summarize the discussions of the working group on Machine Design. The scope of the working group included the entire accelerator system from beam cooling to the collider and the collider ring itself. Particular topics that were discussed in some detail included acceleration options, magnet designs (including the accelerator arcs and collider ring), instabilities, particularly in the collider ring, and lattice issues, particularly in the interaction regions (IRs). Considerable challenges remain in defining a complete machine design for the collider. {copyright} {ital 1996 American Institute of Physics.}

Hirata, K.; Neuffer, D.; Autin, B.; Chen, P.; Cheng, W.; Cline, D.; Dahl, P.; Gallardo, J.; Green, M.; Johnstone, C.; Kahn, S.; Morgan, G.; Ng, K.; Parsah, Z.; Peters, J.; Summers, D.; Tollestrup, A.; Trbojevic, D.

1996-05-01

264

Physics design of linear accelerators for intense ion beams  

SciTech Connect

Advances in the physics and technology of linear accelerators for intense ion beams are leading to new methods for the design of such machines. The physical effects that limit beam current and brightness are better understood and provide the criteria for choosing the rf frequency and for determining optimum focusing configurations to control longitudinal and transverse emittances. During the past decade, the use of developments such as the radio-frequency quadrupole, multiple beams, funneling, ramped-field linac tanks, and self-matching linac tanks is leading to greater design flexibility and improved performance capabilities. 39 refs., 3 tabs., 1 fig.

Wangler, T.P.

1988-01-01

265

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

Microsoft Academic Search

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

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

2008-01-01

266

Acceleration of beam ions during major radius compression in TFTR  

SciTech Connect

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

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

1985-09-01

267

Calculations of beam dynamics in Sandia linear electron accelerators, 1984  

Microsoft Academic Search

A number of code and analytic studies were made during 1984 which pertain to the Sandia linear accelerators MABE and RADLAC. The important results of the calculations are summarized. New results include a better understanding of gap induced radial oscillations, leakage currents in a typical MABE gas, emittance growth in a beam passing through a series of gaps, some new

J. W. Poukey; P. D. Coleman

1985-01-01

268

Accelerator Rings with Polarized Beams and Spin Manipulation  

Microsoft Academic Search

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

Georg H. Hofistaetter

269

Reactive accelerated cluster erosion (RACE) by ionized cluster beams  

NASA Astrophysics Data System (ADS)

Beams of ionized clusters accelerated up to about 120 keV kinetic energy per cluster are used for cluster impact lithography. Chemical reactions of clusters of CO 2, or of SF 6, respectively, are found to assist the physical erosion by hypervelocity cluster impacts in yielding volatile products. Natural diamond, silicon and Pyrex glass have been microstructured showing very smooth eroded surfaces.

Gspann, Jürgen

1996-05-01

270

Cryogenic cooling tests of a neutral particle beam accelerator component  

Microsoft Academic Search

Due to the need to reduce the power requirements and thus the weight of large space-based neutral particle beam (NPB) space platforms, current systems studies propose that these NPB accelerators be maintained at cryogenic temperature levels. As such, the ground test articles that will be used to develop many of the technological advancements necessary prior to engineering development of an

Stephen J. Black

1988-01-01

271

Laser acceleration and nonlinear beam dynamics. Final technical report.  

National Technical Information Service (NTIS)

This research contract covers the period April 1990, September 1991. The work to be done under the contract was theoretical research in the areas of nonlinear beam dynamics and laser acceleration. In this final report we will discuss the motivation for th...

C. Pellegrini

1991-01-01

272

Observation of laser multiple filamentation process and multiple electron beams acceleration in a laser wakefield accelerator  

SciTech Connect

The multiple filaments formation process in the laser wakefield accelerator (LWFA) was observed by imaging the transmitted laser beam after propagating in the plasma of different density. During propagation, the laser first self-focused into a single filament. After that, it began to defocus with energy spreading in the transverse direction. Two filaments then formed from it and began to propagate independently, moving away from each other. We have also demonstrated that the laser multiple filamentation would lead to the multiple electron beams acceleration in the LWFA via ionization-induced injection scheme. Besides, its influences on the accelerated electron beams were also analyzed both in the single-stage LWFA and cascaded LWFA.

Li, Wentao; Liu, Jiansheng; Wang, Wentao; Chen, Qiang; Zhang, Hui; Tian, Ye; Zhang, Zhijun; Qi, Rong; Wang, Cheng; Leng, Yuxin; Li, Ruxin; Xu, Zhizhan [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China)] [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China)

2013-11-15

273

Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators  

SciTech Connect

In the recent plasma wakefield accelerator experiments at SLAC, the energy of the particles in the tail of the 42 GeV electron beam were doubled in less than one meter [1]. Simulations suggest that the acceleration length was limited by a new phenomenon--beam head erosion in self-ionized plasmas. In vacuum, a particle beam expands transversely in a distance given by {beta}*. In the blowout regime of a plasma wakefield [2], the majority of the beam is focused by the ion channel, while the beam head slowly spreads since it takes a finite time for the ion channel to form. It is observed that in self-ionized plasmas, the head spreading is exacerbated compared to that in pre-ionized plasmas, causing the ionization front to move backward (erode). A simple theoretical model is used to estimate the upper limit of the erosion rate for a bi-gaussian beam by assuming free expansion of the beam head before the ionization front. Comparison with simulations suggests that half this maximum value can serve as an estimate for the erosion rate. Critical parameters to the erosion rate are discussed.

Berry, M.K.; 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.

2008-01-28

274

Ion beam generation and focusing on PBFA (Particle Beam Fusion Accelerator) II  

Microsoft Academic Search

During the past year we have succeeded in obtaining a 5 TW\\/cm² proton focus on Sandia National Laboratories' Particle Beam Fusion Accelerator (PBFA) II. This has allowed us to shift our experimental emphasis to the implementation of an improved ion diode geometry for higher voltage operation, full azimuthal beam characterization, and especially lithium ion source experiments. We have made significant

R. W. Stinnett; J. E. Bailey; K. W. Bieg; R. S. Coats; G. Chandler; M. S. Derzon; M. P. Desjarlais; P. L. Dreike; R. A. Gerber; D. J. Johnson; R. J. Leeper; T. R. Lockner; J. Maenchen; T. A. Mehlhorn; A. L. Pregenzer; J. P. Quintenz; T. J. Renk; S. E. Rosenthal; C. L. Ruiz; S. A. Slutz; W. A. Stygar; G. C. Tisone; J. R. Woodworth; Y. Maron

1990-01-01

275

Interactions of Airy beams, nonlinear accelerating beams, and induced solitons in Kerr and saturable nonlinear media.  

PubMed

We investigate numerically interactions between two in-phase or out-of-phase Airy beams and nonlinear accelerating beams in Kerr and saturable nonlinear media in one transverse dimension. We discuss different cases in which the beams with different intensities are launched into the medium, but accelerate in opposite directions. Since both the Airy beams and nonlinear accelerating beams possess infinite oscillating tails, we discuss interactions between truncated beams, with finite energies. During interactions we see solitons and soliton pairs generated that are not accelerating. In general, the higher the intensities of interacting beams, the easier to form solitons; when the intensities are small enough, no solitons are generated. Upon adjusting the interval between the launched beams, their interaction exhibits different properties. If the interval is large relative to the width of the first lobes, the generated soliton pairs just propagate individually and do not interact much. However, if the interval is comparable to the widths of the maximum lobes, the pairs strongly interact and display varied behavior. PMID:24664064

Zhang, Yiqi; Beli?, Milivoj R; Zheng, Huaibin; Chen, Haixia; Li, Changbiao; Li, Yuanyuan; Zhang, Yanpeng

2014-03-24

276

Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude  

DOEpatents

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)

1995-01-01

277

Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude  

DOEpatents

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.

1995-08-08

278

Ion bunch length effects on the beam-beam interaction in a high luminosity ring-ring electron-ion collider with head-on beam-beam compensation  

SciTech Connect

The luminosity of a ring-ring electron-ion collider is limited by the beam-beam effect on the electrons. Simulation studies have shown that for short ion bunches this limit can be significantly increased by head-on beam-beam compensation via an electron lens. However, due to the large beam-beam parameter experienced by the electrons, together with an ion bunch length comparable to the beta-function at the IP, electrons perform a sizeable fraction of a betatron oscillation period inside both the long ion bunches and the electron lens. Recent results of our simulation studies of this effect will be presented.

Montag, C.; Fischer, W.

2010-05-23

279

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

SciTech Connect

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

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

2012-02-15

280

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

281

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

PubMed

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

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

2012-02-01

282

First year of Mark-J: physics with high energy electron-positron colliding beams. Report No. 107  

SciTech Connect

This report reviews the experimental investigation of high energy e/sup +/e/sup -/ interactions by the MARK J collaboration at PETRA, the electron-positron colliding beam accelerator at DESY in Hamburg, West Germany. The physics objectives include studies of several purely electromagnetic processes and hadronic final states, which further our knowledge of the nature of the fundamental constituents and of their strong, electromagnetic and weak interactions. Before discussing the physics results, the main features and the principal components of the MARK J detector are discussed in terms of design, function, and performance. Several aspects of the online data collection and the offline analysis are also outlined. Results are presented on tests of quantum electrodynamics using e/sup +/e/sup -/ ..-->.. e/sup +/e/sup -/, ..mu../sup +/..mu../sup -/ and tau/sup +/tau/sup -/, on the measurement of R, the ratio of the hadronic to the point-like muon pair cross section, on the search for new quark flavors, on the discovery of three jet events arising from the radiation of hard noncollinear gluons as predicted by quantum chromodynamics, and on the determination of the strong coupling constant ..cap alpha../sub s/.

Aachen DESY M.I.T. NIKHEF Peking Collaboration

1980-04-01

283

LATTICES FOR HIGH-POWER PROTON BEAM ACCELERATION AND SECONDARY BEAM COLLECTION AND COOLING.  

SciTech Connect

Rapid cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: (a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics (b) long straight sections for low-loss injection, extraction, and high-efficiency collimation (c) dispersion-free straights to avoid longitudinal-transverse coupling, and (d) momentum cleaning at locations of large dispersion with missing dipoles. Then, we present a lattice for a cooler ring for the secondary beam. The momentum compaction across half of this ring is near zero, while for the other half it is normal. Thus, bad mixing is minimized while good mixing is maintained for stochastic beam cooling.

WANG, S.; WEI, J.; BROWN, K.; GARDNER, C.; LEE, Y.Y.; LOWENSTEIN, D.; PEGGS, S.; SIMOS, N.

2006-06-23

284

Particle-beam accelerators for radiotherapy and radioisotopes  

SciTech Connect

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

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

1981-01-01

285

Design and development of pulsed electron beam accelerator 'AMBICA - 600'  

NASA Astrophysics Data System (ADS)

Short duration, high power pulses with fast rise time and good flat-top are essentially required for driving pulsed electron beam diodes. To attain this objective, a dual resonant Tesla transformer based pulsed power accelerator 'AMBICA-600' has been developed. In this newly developed system, a coaxial water line is charged through single turn Tesla transformer that operates in the dual resonant mode. For making the accelerator compact, in the high power pulse forming line, water has been used as dielectric medium because of its high dielectric constant, high dielectric strength and high energy density. The coaxial waterline can be pulsed charged up to 600kV, has impedance of ~5? and generates pulse width of ~60ns. The integrated system is capable of producing intense electron beam of 300keV, 60kA when connected to impedance matched vacuum diode. In this paper, system hardware details and experimental results of gigawatt electron beam generation have been presented.

Verma, Rishi; Deb, Pankaj; Shukla, Rohit; Sharma, Surender; Shyam, Anurag

2012-11-01

286

Acceleration of electrons in strong beam-plasma interactions  

NASA Technical Reports Server (NTRS)

The effects of strong beam-plasma interactions on the electron population of the upper atmosphere have been investigated in an electron acceleration experiment performed with a sounding rocket. The rocket carried the Several Complex Experiments (SCEX) payload which included an electron accelerator, three disposable 'throwaway' detectors (TADs), and a stepped electron energy analyzer. The payload was launched in an auroral arc over the rocket at altitudes of 157 and 178 km, respectively. The performance characteristics of the instruments are discussed in detail. The data are combined with the results of laboratory measurements and show that electrons with energies of at least two and probably four times the injection energy of 2 keV were observed during strong beam-plasma interaction events. The interaction events occurred at pitch angles of 54 and 126 degrees. On the basis of the data it is proposed that the superenergization of the electrons is correlated with the length of the beam-plasma interaction region.

Wilhelm, K.; Bernstein, W.; Kellogg, P. J.; Whalen, B. A.

1984-01-01

287

Li-beam-heated hohlraum experiments at Particle Beam Fusion Accelerator II  

Microsoft Academic Search

Thermal radiation experiments with 9-MeV Li beams have been performed at Particle Beam Fusion Accelerator II with a peak beam intensity of 1â2TW\\/cm². The peak brightness temperature of the target was 58±4eV. We obtained specific depositions of 800â1600 TW\\/g in the foam. Important features of desired hohlraum performance have been demonstrated. These include a near-Planckian spectrum, increased heating due to

M. S. Derzon; G. A. Chandler; R. J. Dukart; D. J. Johnson; R. J. Leeper; M. K. Matzen; E. J. McGuire; T. A. Mehlhorn; A. R. Moats; R. E. Olson; C. L. Ruiz

1996-01-01

288

CHARGE STRIPPERS FOR ACCELERATION OF URANIUM BEAM AT RIKEN RI-BEAM FACTORY  

Microsoft Academic Search

A uranium beam was accelerated to 345 MeV\\/nucleon using two or three stages of charge strippers at the RIKEN RI-beam factory. The dependence of the charge state dis- tribution of uranium on the carbon foil thickness was mea- sured at 0.67, 0.87, 11, and 51 MeV\\/nucleon. Rotating charge strippers were constructed to strip high-intensity beams. the RIKEN heavy-ion linac (RILAC),

H. Ryuto; H. Hasebe; S. Yokouchi; N. Fukunishi; A. Goto; M. Kase; Y. Yano

289

Trident pair production in colliding bright x-ray laser beams  

NASA Astrophysics Data System (ADS)

The development of strong x-ray lasers motivates the advancement of pair production studies into regions of higher laser frequency. In this paper, a resonant electron-positron pair production process with the absorption of two x-ray photons is considered in the impact of an energetic electron at the overlap region of two colliding x-ray laser beams. The laser-dressed QED method is justified to tackle the complexity of the corresponding multiple Feynman diagrams calculation. The dependence of the production rate as well as the positron energy distribution on the relative angles among the directions of the two laser wave vectors and the incoming electron momentum is revealed. It is shown that the non-plane-wave laser field configuration arouses additional features in the pair production process compared to the plane-wave case.

Hu, Huayu; Huang, Jie

2014-03-01

290

Effect of Field Errors in Muon Collider IR Magnets on Beam Dynamics  

SciTech Connect

In order to achieve peak luminosity of a Muon Collider (MC) in the 10{sup 35} cm{sup -2}s{sup -1} range very small values of beta-function at the interaction point (IP) are necessary ({beta}* {le} 1 cm) while the distance from IP to the first quadrupole can not be made shorter than {approx}6 m as dictated by the necessity of detector protection from backgrounds. In the result the beta-function at the final focus quadrupoles can reach 100 km making beam dynamics very sensitive to all kind of errors. In the present report we consider the effects on momentum acceptance and dynamic aperture of multipole field errors in the body of IR dipoles as well as of fringe-fields in both dipoles and quadrupoles in the ase of 1.5 TeV (c.o.m.) MC. Analysis shows these effects to be strong but correctable with dedicated multipole correctors.

Alexahin, Y.; Gianfelice-Wendt, E.; Kapin, V.V.; /Fermilab

2012-05-01

291

Observations of beam losses due to bound-free pair production in a heavy-ion collider.  

PubMed

We report the first observations of beam losses due to bound-free pair production at the interaction point of a heavy-ion collider. This process is expected to be a major luminosity limit for the CERN Large Hadron Collider when it operates with (208)Pb(82+) ions because the localized energy deposition by the lost ions may quench superconducting magnet coils. Measurements were performed at the BNL Relativistic Heavy Ion Collider (RHIC) during operation with 100 GeV/nucleon (63)Cu(29+) ions. At RHIC, the rate, energy and magnetic field are low enough so that magnet quenching is not an issue. The hadronic showers produced when the single-electron ions struck the RHIC beam pipe were observed using an array of photodiodes. The measurement confirms the order of magnitude of the theoretical cross section previously calculated by others. PMID:17930677

Bruce, R; Jowett, J M; Gilardoni, S; Drees, A; Fischer, W; Tepikian, S; Klein, S R

2007-10-01

292

Detrapping accelerations in a strong electron-beam  

NASA Astrophysics Data System (ADS)

Modulation instabilities and particle-trapping have been observed in space plasmas, and thus it is important to simulate such phenomena in laboratory experiments. In our previous works, electron-beam holes induced by self-trapping were experimentally turned up in phase-space in a weak electron-beam, and their behaviors from emergences to collapses were exhibited [1]. In this work, the self-trapping is further investigated in a strong electron-beam. It is observed that electron-beam branches are formed next to the holes in the high velocity side, and expand with time. These imply that the beam-electrons are detrapped from potential wells of a wave packet. It is confirmed with plotting velocity tips of the branches that the square velocities are proportional to the positions. This proves that accelerations for the beam occur as a result of taking away the wave energy. The holes may play an important role in the accelerations.[1] T. Takeda and K. Yamagiwa, Phys. lett. A, 339, 118-122 (2005).

Takeda, Tsuyoshi

2005-10-01

293

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

NASA Astrophysics Data System (ADS)

The advent of high-intensity-pulsed laser technology enables the generation of extreme states of matter under conditions that are far from thermal equilibrium. This in turn could enable different approaches to generating energy from nuclear fusion. Relaxing the equilibrium requirement could widen the range of isotopes used in fusion fuels permitting cleaner and less hazardous reactions that do not produce high-energy neutrons. Here we propose and implement a means to drive fusion reactions between protons and boron-11 nuclei by colliding a laser-accelerated proton beam with a laser-generated boron plasma. We report proton-boron reaction rates that are orders of magnitude higher than those reported previously. Beyond fusion, our approach demonstrates a new means for exploring low-energy nuclear reactions such as those that occur in astrophysical plasmas and related environments.

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

2013-10-01

294

Laser-driven shock acceleration of monoenergetic ion beams  

NASA Astrophysics Data System (ADS)

Ion acceleration from laser-plasma interactions is a promising approach for compact and bright ion sources. However, the conditions for optimization of the beam quality and energy are not yet fully understood. We show that the use of tailored critical-density targets, with a steep density ramp at the front and an exponential ramp at the back, which can be obtained in realistic experimental conditions, enables the generation of high quality and high energy ion beams accelerated by a laser-driven electrostatic shock. The laser deposits most of its energy in a localized region at critical density, heating the electrons and generating an electrostatic shock. The shock can then reflect most of the ions from the back of the target to high energies before competing accelerating fields (like TNSA) develop significantly, leading to high quality beams. Our PIC simulation results illustrate the possibility of generating high quality proton beams with energies in the required range for medical applications (100-300 MeV) with moderate laser intensities (a0 ˜ 10).

Boella, Elisabetta; Fiuza, Frederico; Fonseca, Ricardo A.; Silva, Luis O.; Haberberger, Dan; Tochitsky, Sergei; Gong, Chao; Mori, Warren B.; Joshi, Chan

2011-11-01

295

High fidelity 3-dimensional models of beam-electron cloud interactions in circular accelerators  

NASA Astrophysics Data System (ADS)

Electron cloud is a low-density electron profile created inside the vacuum chamber of circular machines with positively charged beams. Electron cloud limits the peak current of the beam and degrades the beams' quality through luminosity degradation, emittance growth and head to tail or bunch to bunch instability. The adverse effects of electron cloud on long-term beam dynamics becomes more and more important as the beams go to higher and higher energies. This problem has become a major concern in many future circular machines design like the Large Hadron Collider (LHC) under construction at European Center for Nuclear Research (CERN). Due to the importance of the problem several simulation models have been developed to model long-term beam-electron cloud interaction. These models are based on "single kick approximation" where the electron cloud is assumed to be concentrated at one thin slab around the ring. While this model is efficient in terms of computational costs, it does not reflect the real physical situation as the forces from electron cloud to the beam are non-linear contrary to this model's assumption. To address the existing codes limitation, in this thesis a new model is developed to continuously model the beam-electron cloud interaction. The code is derived from a 3-D parallel Particle-In-Cell (PIC) model (QuickPIC) originally used for plasma wakefield acceleration research. To make the original model fit into circular machines environment, betatron and synchrotron equations of motions have been added to the code, also the effect of chromaticity, lattice structure have been included. QuickPIC is then benchmarked against one of the codes developed based on single kick approximation (HEAD-TAIL) for the transverse spot size of the beam in CERN-LHC. The growth predicted by QuickPIC is less than the one predicted by HEAD-TAIL. The code is then used to investigate the effect of electron cloud image charges on the long-term beam dynamics, particularly on the transverse tune shift of the beam at CERN Super Proton Synchrotron (SPS) ring. The force from the electron cloud image charges on the beam cancels the force due to cloud compression formed on the beam axis and therefore the tune shift is mainly due to the uniform electron cloud density. (Abstract shortened by UMI.)

Feiz Zarrin Ghalam, Ali

296

Recent advances for ion beam therapy accelerators using synchrotrons  

NASA Astrophysics Data System (ADS)

Ion beam therapy has evolved a lot during the last years. After more than a decade of successful clinical studies and first treatment in hospital environment, the carbon beam treatment, which always relies on a synchrotron as main accelerator, has clearly shown its own potential. The clinical success of carbon beam treatment is indicated by the growing number of new fully clinical based facilities. There is a lot of improvement potential for these facilities in order to increase their treatment quality, functionality and capacity as well as the cost effectiveness of the patient treatment. This article focuses on the currently ongoing investigations to fully explore this potential. It can be concluded that synchrotron based ion beam facilities are improving into many directions. This will further improve their impact on the cancer treatment and consequently their benefit to the whole society.

Weinrich, U.

2011-12-01

297

Challenges in future linear colliders  

SciTech Connect

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

Swapan Chattopadhyay; Kaoru Yokoya

2002-09-02

298

ELIMED, future hadrontherapy applications of laser-accelerated beams  

NASA Astrophysics Data System (ADS)

Laser-ion acceleration has recently gained a great interest as an alternative to conventional and more expensive acceleration techniques. These ion beams have desirable qualities such as small source size, high luminosity and small emittance to be used in different fields as Nuclear Physics, Medical Physics, etc. This is very promising specially for the future perspective of a new concept of hadrontherapy based on laser-based devices could be developed, replacing traditional accelerating machines. Before delivering laser-driven beams for treatments they have to be handled, cleaned from unwanted particles and characterized in order to have the clinical requirements. In fact ion energy spectra have exponential trend, almost 100% energy spread and a wide angular divergence which is the biggest issue in the beam transport and, hence, in a wider use of this technology. In order to demonstrate the clinical applicability of laser-driven beams new collaboration between ELI-Beamlines project researchers from Prague (Cz) and a INFN-LNS group from Catania (I) has been already launched and scientists from different countries have already express their will in joining the project. This cooperation has been named ELIMED (MEDical application at ELIBeamlines) and will take place inside the ELI-Beamlines infrastructure located in Prague. This work describes the schedule of the ELIMED project and the design of the energy selector which will be realized at INFN-LNS. The device is an important part of the whole transport beam line which will be realised in order to make the ion beams suitable for medical applications.

Cirrone, Giuseppe A. P.; Carpinelli, Massimo; Cuttone, Giacomo; Gammino, Santo; Bijan Jia, S.; Korn, Georg; Maggiore, Mario; Manti, Lorenzo; Margarone, Daniele; Prokupek, Jan; Renis, Marcella; Romano, Francesco; Schillaci, Francesco; Tomasello, Barbara; Torrisi, Lorenzo; Tramontana, Antonella; Velyhan, Andriy

2013-12-01

299

Beam dynamics simulation of the Spallation Neutron Source linear accelerator  

SciTech Connect

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

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

1998-12-31

300

Study of a multi-beam accelerator driven thorium reactor  

SciTech Connect

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

Ludewig, H.; Aronson, A.

2011-03-01

301

Bipolar pulse generator for intense pulsed ion beam accelerator  

SciTech Connect

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

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

2007-01-15

302

Million revolution accelerator beam instrument for logging and evaluation  

SciTech Connect

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

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

1988-03-01

303

Advanced Surface Polishing for Accelerator Technology using Ion Beams  

SciTech Connect

A gas cluster ion beam (GCIB) technology was successfully applied to surface treatment of Cu, stainless steel, Ti, and Nb samples and to Nb rf-cavities by using accelerated cluster ion beams of Ar, O2 and combinations of them, with accelerating voltages up to 35 kV. DC field emission (dark current) measurements and electron microscopy were used to investigate metal surfaces treated by GCIB. The experimental results showed that GCIB technique can significantly reduce the number of field emitters and can change the structure of the Nb oxide layer on the surface. The RF tests of the GCIB-treated Nb rf-cavities showed improvement of the quality factor Q at 4.5 K. The superconducting gap was also enhanced by using the oxygen GCIB irradiation exposure.

Z. Insepov, Jim Norem, Andy Wu

2009-03-01

304

Use of Crystals for Beam Deflection in Particle Accelerators  

NASA Astrophysics Data System (ADS)

Charged particles interacting with a bent crystal can be trapped in channeling states and deflected by the atomic planes of the crystal lattice. The use of bent crystals for beam manipulation in particle accelerators is a well assessed concept rapidly evolving into practical applications. In the last three decades, a large number of experimental findings have contributed to clarify our knowledge and to improve our control of crystal-particle interactions. Bent crystals can impart angular deflections to the incoming particles, through channeling or volume reflection mechanisms. The efficiency of the latter mechanism has been found to be intrinsically very large, whilst the channeling efficiency has been improved by the increased technological expertize in crystal cutting and bending. In this paper, we review the recent milestones of the worldwide effort to propose a routine use of bent crystals in particle accelerators, with a specific attention to the proposals of promoting the use of bent crystals as primary element in beam halo collimation systems.

Scandale, Walter

305

Trends for Electron Beam Accelerator Applications in Industry  

NASA Astrophysics Data System (ADS)

Electron beam (EB) accelerators are major pieces of industrial equipment used for many commercial radiation processing applications. The industrial use of EB accelerators has a history of more than 50 years and is still growing in terms of both its economic scale and new applications. Major applications involve the modification of polymeric materials to create value-added products, such as heat-resistant wires, heat-shrinkable sheets, automobile tires, foamed plastics, battery separators and hydrogel wound dressing. The surface curing of coatings and printing inks is a growing application for low energy electron accelerators, resulting in an environmentally friendly and an energy-saving process. Recently there has been the acceptance of the use of EB accelerators in lieu of the radioactive isotope cobalt-60 as a source for sterilizing disposable medical products. Environmental protection by the use of EB accelerators is a new and important field of application. A commercial plant for the cleaning flue gases from a coal-burning power plant is in operation in Poland, employing high power EB accelerators. In Korea, a commercial plant uses EB to clean waste water from a dye factory.

Machi, Sueo

2011-02-01

306

Acceleration of Intense Positive Ion Beams at Megavolt Potentials  

Microsoft Academic Search

The long range objective of the ion accelerator development at RDI is to achieve a proton beam current of 5 to 10 mA at 3 to 5 MeV energy. Present performance is limited to 3 mA of mixed hydrogen ions at 3 MeV and 2 mA at 4 MeV despite the fact that both ion source and high voltage generators

M. R. Cleland; P. R. Hanley; C. C. Thompson

1969-01-01

307

Manipulating nonlinear optical processes with accelerating light beams  

SciTech Connect

We show theoretically that accelerating light beams can be used to manipulate nonlinear optical processes through spatiotemporal quasi-phase-matching, allowing for unprecedented temporal and spectral shaping of the generated light. As a proof of principle, we demonstrate exquisite control over the high-order harmonic frequency conversion process, showing efficient enhancement of an extremely broad range of harmonics emitted during a selected quarter-cycle of the driving laser pulse.

Bahabad, Alon [Department of Physical Electronics, Tel-Aviv University, Tel-Aviv 69978 (Israel); JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Murnane, Margaret M.; Kapteyn, Henry C. [JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States)

2011-09-15

308

First Beam Waist Measurements in the Final Focus Beam Line at the KEK Accelerator Test Facility  

SciTech Connect

The ATF2 project is the final focus system prototype for the ILC and CLIC linear collider projects, with a purpose to reach a 37 nm vertical beam size at the interaction point using compact optics based on a novel scheme of local chromaticity correction. Construction of all components and installation were completed at the end of 2008. An initial commissioning phase followed in 2009, using larger than nominal {beta} functions at the interaction point, corresponding to reduced demagnification factors in comparison to the design, to limit effects from higher-order optical aberrations and hence simplify beam tuning procedures while key instrumentation was being tested and calibrated. In this paper, first measurements of dispersion and Twiss parameters are presented based on scanning the beam during this period with a set of tungsten wires located just behind the interaction point, using two complementary analysis methods.

Bai, Sha; /Beijing, Inst. High Energy Phys.; Aryshev, Alexander; /KEK, Tsukuba; Bambade, Philip; /KEK, Tsukuba /Orsay, IPN; McCormick, Doug; /SLAC; Bolzon, Benoit; /Annecy, LAPP; Gao, Jie; /Beijing, Inst. High Energy Phys.; Tauchi, Toshiaki; /KEK, Tsukuba; Zhou, Feng; /SLAC

2012-06-22

309

First beam waist measurements in the final focus beam line at the KEK Accelerator Test Facility  

NASA Astrophysics Data System (ADS)

The ATF2 project is the final focus system prototype for the ILC and CLIC linear collider projects, with a purpose to reach a 37 nm vertical beam size at the interaction point using compact optics based on a novel scheme of local chromaticity correction. Construction of all components and installation were completed at the end of 2008. An initial commissioning phase followed in 2009, using larger than nominal ? functions at the interaction point, corresponding to reduced demagnification factors in comparison to the design, to limit effects from higher-order optical aberrations and hence simplify beam tuning procedures while key instrumentation was being tested and calibrated. In this paper, first measurements of dispersion and Twiss parameters are presented based on scanning the beam during this period with a set of tungsten wires located just behind the interaction point, using two complementary analysis methods.

Bai, Sha; Aryshev, Alexander; Bambade, Philip; Mc Cormick, Doug; Bolzon, Benoit; Gao, Jie; Tauchi, Toshiaki; Zhou, Feng

2010-09-01

310

Studies of beam induced dipole mode signals in accelerating structures at the SLC  

Microsoft Academic Search

Beam emittance dilution by self induced transverse fields (wakefields) in accelerating structures is a key problem in linear accelerators. To minimize the wakefield effects the beam trajectory must be precisely centered within the struc- tures. An efficient way to achieve this is to detect beam induced microwave signals in the lowest dipole mode band and to steer the beam by

Mike Seidel

1998-01-01

311

Heavy ion beam-ionosphere interactions - Electron acceleration  

NASA Technical Reports Server (NTRS)

Moore et al. (1982) described a number of unexpected effects which were observed during the first Argon Release Controlled Study (ARCS 1, or rocket flight 29:014). The present paper provides a description of detailed analyses of the interaction of the argon beam with the ionosphere. An important feature of the considered test was that all detectors and the Ar(+) gun remained attached to the rocket throughout the flight. It is pointed out that the most dramatic effect of ion gun operation on ARCS 1 involved large changes in the fluxes of electrons with energies below about 600 eV. The observations are discussed, taking into account the distribution functions, azimuth dependence, and electron and ion trajectories. Attention is given to the perpendicular ion beam, the parallel ion beam, the acceleration of downgoing and upgoing electrons, and aspects of wave generation.

Kaufmann, R. L.; Arnoldy, R. L.; Moore, T. E.; Kintner, P. M.; Cahill, L. J., Jr.

1985-01-01

312

Resolving EMI Issues To Optimize Accelerator Beam Diagnostic Performance  

SciTech Connect

If you have struggled to get the last bit of performance from a beam diagnostic only to find your dynamic range limited by external sources of electromagnetic interference (EMI) once the system is installed, then you will find this tutorial on electromagnetic compatibility and grounding useful. The tutorial will provide some simple, direct methods to analyze, understand and mitigate the impact of EMI on beam diagnostic systems. Several common and unique accelerator EMI sources will be characterized. The dependencies of source frequency and distance to the source on the optimal choice of grounding and shielding methods will be illustrated. The emphasis is on a stepwise process that leads to understanding and cost-effective resolution of EMI impacts on beam diagnostic systems.

Thuot, Michael [Los Alamos National Laboratory, LANSCE Division, Los Alamos, New Mexico (United States)

2004-11-10

313

Design consideration of relativistic klystron two-beam accelerator for suppression of beam-break-up  

SciTech Connect

It is demonstrated in this simulation study that by using the scheme of operating rf extraction structures on the betatron nodes of electron drive beam in conjunction with adequate de-Q-ing, appropriate choice of geometries for the rf structures (reducing transverse impedence) and/or staggered tuning we can suppress the overall growth of transverse instabilities to 4 e-folds in a relativistic klystron two-beam accelerator with 200 extraction cavities.

Li, H.; Houck, T.L.; Yu, S.; Goffeney, N.

1994-03-01

314

Beam losses from ultra-peripheral nuclear collisions between Pb ions in the Large Hadron Collider and their alleviation  

SciTech Connect

Electromagnetic interactions between colliding heavy ions at the Large Hadron Collider (LHC) at CERN will give rise to localized beam losses that may quench superconducting magnets, apart from contributing significantly to the luminosity decay. To quantify their impact on the operation of the collider, we have used a three-step simulation approach, which consists of optical tracking, a Monte-Carlo shower simulation and a thermal network model of the heat flow inside a magnet. We present simulation results for the case of {sup 208}Pb{sup 82+} ion operation in the LHC, with focus on the alice interaction region, and show that the expected heat load during nominal {sup 208}Pb{sup 82+} operation is 40% above the quench level. This limits the maximum achievable luminosity. Furthermore, we discuss methods of monitoring the losses and possible ways to alleviate their effect.

Bruce, R.; /CERN; Bocian, D.; /Fermilab /CERN; Gilardoni, S.; Jowett, J.M.; /CERN

2009-08-01

315

Positron source investigation by using CLIC drive beam for Linac-LHC based e+p collider  

NASA Astrophysics Data System (ADS)

Three different methods which are alternately conventional, Compton backscattering and Undulator based methods employed for the production of positrons. The positrons to be used for e+p collisions in a Linac-LHC (Large Hadron Collider) based collider have been studied. The number of produced positrons as a function of drive beam energy and optimum target thickness has been determined. Three different targets have been used as a source investigation which are W75-Ir25, W75-Ta25, and W75-Re25 for three methods. Estimated number of the positrons has been performed with FLUKA simulation code. Then, these produced positrons are used for following Adiabatic matching device (AMD) and capture efficiency is determined. Then e+p collider luminosity corresponding to the methods mentioned above have been calculated by CAIN code.

Ar?kan, Ertan; Aksakal, Hüsnü

2012-08-01

316

On the development of an ion-beam stochastic cooling system for the nuclotron superconducting accelerator complex  

NASA Astrophysics Data System (ADS)

The Joint Institute for Nuclear Research (JINR) initiated the creation of a unique heavy-ion collider, the Nuclotron-based ion collider facility (NICA), which is planned to be put into commission in 2016. According to the calculation data, the collider luminosity, which should be kept at a record high level of 1027 cm-2 s-1, will gradually decrease, mainly due to intrabeam scattering. To maintain luminosity at a high level, it is necessary to include a cooling system in the base project of the accelerator. Among the two cooling methods (electron and stochastic) most frequently used for heavy ion beams, stochastic cooling seems more attractive. However, there has been a lack of experience in the development and commissioning of such systems in Russia. For this reason, an experiment on stochastic cooling on the Nuclotron accelerator is being prepared to explore the technology and possibilities of this method. In this work, the method of stochastic cooling, the technique for calculating the cooling dynamics, and the experimental setup under development are briefly described.

Kobets, A. G.; Sidorin, A. O.; Trubnikov, G. V.; Shurkhno, N. A.

2012-07-01

317

Design of Three Re-Circulating Superconducting RF Accelerating Systems for a 4-TeV Muon Collider  

NASA Astrophysics Data System (ADS)

Muon collliders can provide strong potential advantages in high energy physics and are an attractive alternative to e^-e^+ colliders due to the small synchrotron losses. The design of the accelerating systems for muon however is technically very challenging since very rapidly increasing in muon energies is required due to the short life time of 2.2 x 10-6 s at rest. In a conceptual design of the accelerating system, three re-circulating Linacs (with energies reaching 70 GeV (with 350-MHz SRF, 10-MV/m), 250 GeV (800-MHz, 20-MV/m) and 2000 GeV (1300-GHz, 25-MV/m), respectively) are chosen. The cryogenic systems must provide 2-K superfluid LHe to the SRF 1300-GHz Linac and 4-K normal LHe to the 350-MHz and 800-MHz Linacs. We present the basic design concepts of the superconducting RF cavities, input and HOM couplers, the RF high power klystrons, low level RF control and its associated cryogenic system in a 4-TeV muon collider.

Shu, Q.-S.; Neuffer, D.; Simrock, S.

1997-05-01

318

Preservation and control of the proton and deuteron polarizations in the proposed electron-ion collider at Jefferson Lab  

SciTech Connect

We propose a scheme of preserving the proton and deuteron beam polarizations during acceleration and storage in the proposed electron-ion collider at Jefferson Lab. This scheme allows one to provide both the longitudinal and transverse polarization orientations of the proton and deuteron beams at the interaction points of the figure-8 ion collider ring. We discuss questions of matching the polarization direction at all stages of the beam transport including the pre-booster, large booster and ion collider ring.

Kondratenko, Anatoliy [Scientific and Technical Laboratory Zaryad, Novosibirsk (Russian Federation); Derbenev, Yaroslav S. [JLAB, Newport News, VA (United States); Filatov, Yury [Moscow Institute of Physics and Technology, Dolgoprudny (Russian Federation); Lin, Fanglei [JLAB, Newport News, VA (United States); Morozov, Vasiliy [JLAB, Newport News, VA (United States); Kondratenko, M. A. [Scientific and Technical Laboratory Zaryad, Novosibirsk (Russian Federation); Zhang, Yuhong [JLAB, Newport News, VA (United States)

2014-01-01

319

Seismic studies for Fermilab future collider projects  

SciTech Connect

Ground motion can cause significant beam emittance growth and orbit oscillations in large hadron colliders due to a vibration of numerous focusing magnets. Larger accelerator ring circumference leads to smaller revolution frequency and, e.g. for the Fermilab Very Large Hadron Collider(VLHC) 50-150 Hz vibrations are of particular interest as they are resonant with the beam betatron frequency. Seismic measurements at an existing large accelerator under operation can help to estimate the vibrations generated by the technical systems in future machines. Comparison of noisy and quiet microseismic conditions might be useful for proper choice of technical solutions for future colliders. This article presents results of wide-band seismic measurements at the Fermilab site, namely, in the tunnel of the Tevatron and on the surface nearby, and in two deep tunnels in the Illinois dolomite which is though to be a possible geological environment of the future accelerators.

Lauh, J.; Shiltsev, V.

1997-11-01

320

Ion beam generation and focusing on PBFA (Particle Beam Fusion Accelerator) II  

SciTech Connect

During the past year we have succeeded in obtaining a 5 TW/cm{sup 2} proton focus on Sandia National Laboratories' Particle Beam Fusion Accelerator (PBFA) II. This has allowed us to shift our experimental emphasis to the implementation of an improved ion diode geometry for higher voltage operation, full azimuthal beam characterization, and especially lithium ion source experiments. We have made significant progress in each of these areas during the past year, demonstrating 10 MV diode operation, {plus minus}10% azimuthal beam symmetry, and promising initial results from lithium ion source experiments. 8 refs., 6 figs.

Stinnett, R.W.; Bailey, J.E.; Bieg, K.W.; Coats, R.S.; Chandler, G.; Derzon, M.S.; Desjarlais, M.P.; Dreike, P.L.; Gerber, R.A.; Johnson, D.J.; Leeper, R.J.; Lockner, T.R.; Maenchen, J.; Mehlhorn, T.A.; Pregenzer, A.L.; Quintenz, J.P.; Renk, T.J.; Rosenthal, S.E.; Ruiz, C.L.; Slutz, S.A.; Stygar, W.A.; Tisone, G.C.; Woodworth, J.R. (Sandia National Labs., Albuquerque, NM (USA)); Maron, Y. (Weizmann Inst. of Science, R

1990-01-01

321

Radiation Safety System for SPIDER Neutral Beam Accelerator  

SciTech Connect

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

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

2011-12-13

322

Radiation Safety System for SPIDER Neutral Beam Accelerator  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

323

High energy electron beam processing experiments with induction accelerators  

NASA Astrophysics Data System (ADS)

Induction accelerators are capable of producing very high electron beam power for processing at energies of 1-10 MeV. A high energy electron beam (HEEB) material processing system based on all-solid-state induction accelerator technology is in operation at Science Research Laboratory. The system delivers 50 ns 500 A current pulses at 1.5 MeV and is capable of operating at high power (500 kW) and high (˜ 5 kHz) repetition rate. HEEB processing with induction accelerators is useful for a wide variety of applications including the joining of high temperature materials, powder metallurgical fabrication, treatment of organic-contaminated wastewater and the curing of polymer matrix composites. High temperature HEEB experiments at SRL have demonstrated the brazing of carbon-carbon composites to metallic substrates and the melting and sintering of powders for graded-alloy fabrication. Other experiments have demonstrated efficient destruction of low-concentration organic contaminants in water and low temperature free-radical cross-linking of fiber-reinforced composites with acrylated resin matrices.

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

1995-05-01

324

Large Hadron Collider at CERN: Beams generating high-energy-density matter.  

PubMed

This paper presents numerical simulations that have been carried out to study the thermodynamic and hydrodynamic responses of a solid copper cylindrical target that is facially irradiated along the axis by one of the two Large Hadron Collider (LHC) 7 TeV/ c proton beams. The energy deposition by protons in solid copper has been calculated using an established particle interaction and Monte Carlo code, FLUKA, which is capable of simulating all components of the particle cascades in matter, up to multi-TeV energies. These data have been used as input to a sophisticated two-dimensional hydrodynamic computer code BIG2 that has been employed to study this problem. The prime purpose of these investigations was to assess the damage caused to the equipment if the entire LHC beam is lost at a single place. The FLUKA calculations show that the energy of protons will be deposited in solid copper within about 1 m assuming constant material parameters. Nevertheless, our hydrodynamic simulations have shown that the energy deposition region will extend to a length of about 35 m over the beam duration. This is due to the fact that first few tens of bunches deposit sufficient energy that leads to high pressure that generates an outgoing radial shock wave. Shock propagation leads to continuous reduction in the density at the target center that allows the protons delivered in subsequent bunches to penetrate deeper and deeper into the target. This phenomenon has also been seen in case of heavy-ion heated targets [N. A. Tahir, A. Kozyreva, P. Spiller, D. H. H. Hoffmann, and A. Shutov, Phys. Rev. E 63, 036407 (2001)]. This effect needs to be considered in the design of a sacrificial beam stopper. These simulations have also shown that the target is severely damaged and is converted into a huge sample of high-energy density (HED) matter. In fact, the inner part of the target is transformed into a strongly coupled plasma with fairly uniform physical conditions. This work, therefore, has suggested an additional very important application of the LHC, namely, studies of HED states in matter. PMID:19518362

Tahir, N A; Schmidt, R; Shutov, A; Lomonosov, I V; Piriz, A R; Hoffmann, D H H; Deutsch, C; Fortov, V E

2009-04-01

325

Diffusion bonding and brazing of high purity copper for linear collider accelerator structures  

Microsoft Academic Search

Diffusion bonding and brazing of high purity copper were investigated to develop procedures for joining precision machined copper components for the Next Linear Collider (NLC). Diffusion bonds were made over a range of temperatures from 400 °C to 1000 °C, under two different loading conditions [3.45 kPa (0.5 psi) and 3.45 MPa (500 psi)], and on two different diamond machined

J. W. Elmer; J. Klingmann; K. van Bibber

2001-01-01

326

Accelerator-colliders for relativistic heavy ions or in search of luminosity  

SciTech Connect

Some issues pertinent to the design of collider rings for relativistic heavy ions are presented. Experiments at such facilities are felt to offer the best chance for creating in the laboratory a new phase of subatomic matter, the quark-gluon plasma. It appears possible to design a machine with sufficient exploration of the heaviest nuclei in nature, to allow a thorough exploration of quark-gluon plasma.

Young, G.R.

1984-11-15

327

Accelerator-colliders for relativistic heavy ions or in search of luminosity  

SciTech Connect

Some issues pertinent to the design of collider rings for relativistic heavy ions are presented. Experiments at such facilities are felt to offer the best chance for creating in the laboratory a new phase of subatomic matter, the quark-gluon plasma. It appears possible to design a machine with sufficient luminosity, even for the heaviest nuclei in nature, to allow a thorough exploration of the production conditions and decay characteristics of quark-gluon plasma.

Young, G.R.

1984-01-01

328

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). First, a scintillating screen (Lanex) was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT) for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/(ps mm{sup 2}), respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within {+-}8%, showing that they all can provide accurate charge measurements for LPAs.

Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Smith, Alan; Rodgers, David; Donahue, Rich; Byrne, Warren; Leemans, Wim

2011-06-27

329

Beam energy scaling of a stably operated laser wakefield accelerator  

SciTech Connect

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

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

2010-06-15

330

RF pulse compression for future linear colliders  

SciTech Connect

Future (nonsuperconducting) linear colliders will require very high values of peak rf power per meter of accelerating structure. The role of rf pulse compression in producing this power is examined within the context of overall rf system design for three future colliders at energies of 1.0--1.5 TeV, 5 TeV and 25 TeV. In order keep the average AC input power and the length of the accelerator within reasonable limits, a collider in the 1.0--1.5 TeV energy range will probably be built at an x-band rf frequency, and will require a peak power on the order of 150--200 MW per meter of accelerating structure. A 5 TeV collider at 34 GHz with a reasonable length (35 km) and AC input power (225 MW) would require about 550 MW per meter of structure. Two-beam accelerators can achieve peak powers of this order by applying dc pulse compression techniques (induction linac modules) to produce the drive beam. Klystron-driven colliders achieve high peak power by a combination of dc pulse compression (modulators) and rf pulse compression, with about the same overall rf system efficiency (30--40%) as a two-beam collider. A high gain (6.8) three-stage binary pulse compression system with high efficiency (80%) is described, which (compared to a SLED-11 system) can be used to reduce the klystron peak power by about a factor of two, or alternately, to cut the number of klystrons in half for a 1.0--1.5 TeV x-band collider. For a 5 TeV klystron-driven collider, a high gain, high efficiency rf pulse compression system is essential.

Wilson, P.B.

1995-05-01

331

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

SciTech Connect

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

2011-09-01

332

New Fusion Concept Using Coaxial Passing Through Each Other Self-focusing Colliding Beams (Invention)  

NASA Astrophysics Data System (ADS)

In proposed Concept it is offered to use two ion beams directed coaxially at the same direction but with different velocities (center-of-mass collision energy should be sufficient for fusion), to direct oppositely the relativistic electron beam for only partial compensation of positive space charge and for allowing the combined beam's pinch capability, to apply the longitudinal electric field for compensation of alignment of velocities of reacting particles and also for compensation of energy losses of electrons via Bremsstrahlung. On base of Concept different types of reactor designs can be realized: Linear and Cyclic designs. In the simplest embodiment the Cyclic Reactor (design) may include: betatron type device (circular store of externally injected particles -- induction accelerator), pulse high-current relativistic electron injector, pulse high-current slower ion injector, pulse high-current faster ion injector and reaction products extractor. Using present day technologies and materials (or a reasonable extrapolation of those) it is possible to reach: for induction linear injectors (ions&electrons) -- currents of thousands A, repeatability -- up to 10Hz, the same for high-current betatrons (FFAG, Stellatron, etc.). And it is possible to build the fusion reactor using the proposed Method just today.

Chikvashvili, Ioseb

2011-11-01

333

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

SciTech Connect

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

Karas', V. I.; Manuilenko, O. V. [National Science Center Kharkov Institute of Physics and Technology (Ukraine)] [National Science Center Kharkov Institute of Physics and Technology (Ukraine); Tarakanov, V. P. [Russian Academy of Sciences, Joint Institute for High Temperature (Russian Federation)] [Russian Academy of Sciences, Joint Institute for High Temperature (Russian Federation); Federovskaya, O. V. [National Science Center Kharkov Institute of Physics and Technology (Ukraine)] [National Science Center Kharkov Institute of Physics and Technology (Ukraine)

2013-03-15

334

Accelerating Radioactive Ion Beams With REX-ISOLDE  

SciTech Connect

The post accelerator REX-ISOLDE is installed at the ISOLDE facility at CERN, where a broad variety of radioactive ions can be addressed. Since the end of 2001 beams at the final energy of 2.2 MeV/u are available. REX-ISOLDE uses a unique system of beam bunching and charge breeding. First a Penning trap accumulates and bunches the ions, which are delivered as a quasi-continuous beam from the ISOLDE target-ion-source, and then an electron beam ion source (EBIS) charge-breeds them to a mass-to-charge ratio below 4.5. This enables a very compact design for the following LINAC, consisting of a 4 rod RFQ, an IH structure and three 7-gap-resonators. The later ones allow a variation of the final energy between 0.8 and 2.2 MeV/u. Although the machine is still in the commissioning phase, first physics experiments have been done with neutron rich Na and Mg isotopes and 9Li. A total efficiency of several percent has already been obtained.

Ames, F.; Emhofer, S.; Habs, D.; Kester, O.; Reisinger, K.; Sieber, T. [Sektion Physik, LMU, Muenchen, D-85748 Garching (Germany); Bollen, G. [NSCL, Michigan State University, East Lansing, MI 48824 (United States); Cederkaell, J.; Forstner, O.; Wenander, F. [CERN, CH-1211 Geneva 23 (Switzerland); Huber, G.; Wolf, B. [Institut fuer Physik, J. Gutenberg-Universitaet, D-55099 Mainz (Germany); Schwalm, D.; Hahn, R. von [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Bergh, P. van den; Duppen, P. van [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, B-3001 Leuven (Belgium)

2003-08-26

335

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)

2005-12-15

336

Lévy-Student distributions for halos in accelerator beams.  

PubMed

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 Schrödinger-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, Lévy 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) Lévy 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 Lévy-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. PMID:16486070

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

2005-12-01

337

Flyer Acceleration by Pulsed Ion Beam Ablation and Application for Space Propulsion  

Microsoft Academic Search

Flyer acceleration by ablation plasma pressure produced by irradiation of intense pulsed ion beam has been studied. Acceleration process including expansion of ablation plasma was simulated based on fluid model. And interaction between incident pulsed ion beam and a flyer target was considered as accounting stopping power of it. In experiments, we used ETIGO-II intense pulsed ion beam generator with

Nobuhiro Harada; Chainarong Buttapeng; Masaru Yazawa; Kenji Kashine; Weihua Jiang; Kiyoshi Yatsui

2004-01-01

338

Experimental estimate of beam loading and minimum rf voltage for acceleration of high intensity beam in the Fermilab Booster  

SciTech Connect

The difference between the rf voltage seen by the beam and the accelerating voltage required to match the rate of change of the Booster magnetic field is used to estimate the energy loss per beam turn. Because the rf voltage (RFSUM) and the synchronous phase can be experimentally measured, they can be used to calculate the effective accelerating voltage. Also an RFSUM reduction technique has been applied to measure experimentally the RFSUM limit at which the beam loss starts. With information on beam energy loss, the running conditions, especially for the high intensity beam, can be optimized in order to achieve a higher intensity beam from the Fermilab Booster.

Xi Yang; Charles M Ankenbrandt and Jim Norem

2004-04-01

339

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

SciTech Connect

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

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

1993-09-01

340

Powerful high-voltage generators for FELTRON, the electrostatic-accelerator FEL amplifier for TeV colliders  

NASA Astrophysics Data System (ADS)

One of the crucial issues of the new ?-wave source FELTRON is the high-voltage generator. FELTRON is a powerful electrostatic FEL providing ?-wave radiation at 20 GHz, with peak power of 200 MW, pulse length of 500 ns (derived in ten separate beams of 50 ns each) at a repetition rate of 1 kHz. This radiation power will feed the cavities of a high gradient linac for TeV colliders. The average power of the generator must be around 250 kW, at a voltage of 5 MV. A Cockroft-Walton having the "onion" configuration is presented. The features are compared with those of dynamitron and insulating core transformer generators. The operation principles and technological problems are discussed in view of pulsed FEL utilization.

Boscolo, I.; Giuliani, F.; Roche, M.

1992-07-01

341

Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider  

NASA Astrophysics Data System (ADS)

The Large Hadron Collider (LHC) is designed to collide two proton beams with unprecedented particle energy of 7 TeV. Each beam comprises 2808 bunches and the separation between two neighboring bunches is 25 ns. The energy stored in each beam is 362 MJ, sufficient to melt 500 kg copper. Safety of operation is very important when working with such powerful beams. An accidental release of even a very small fraction of the beam energy can result in severe damage to the equipment. The machine protection system is essential to handle all types of possible accidental hazards; however, it is important to know about possible consequences of failures. One of the critical failure scenarios is when the entire beam is lost at a single point. In this paper we present detailed numerical simulations of the full impact of one LHC beam on a cylindrical solid carbon target. First, the energy deposition by the protons is calculated with the FLUKA code and this energy deposition is used in the BIG2 code to study the corresponding thermodynamic and the hydrodynamic response of the target that leads to a reduction in the density. The modified density distribution is used in FLUKA to calculate new energy loss distribution and the two codes are thus run iteratively. A suitable iteration step is considered to be the time interval during which the target density along the axis decreases by 15%-20%. Our simulations suggest that the full LHC proton beam penetrates up to 25 m in solid carbon whereas the range of the shower from a single proton in solid carbon is just about 3 m (hydrodynamic tunneling effect). It is planned to perform experiments at the experimental facility HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS), to compare experimental results with the theoretical predictions. Therefore simulations of the response of a solid copper cylindrical target hit by the SPS beam were performed. The particle energy in the SPS beam is 440 GeV while it has the same bunch structure as the LHC beam, except that it has only up to 288 bunches. Beam focal spot sizes of ?=0.1, 0.2, and 0.5 mm have been considered. The phenomenon of significant hydrodynamic tunneling due to the hydrodynamic effects is also expected for the experiments.

Tahir, N. A.; Sancho, J. Blanco; Shutov, A.; Schmidt, R.; Piriz, A. R.

2012-05-01

342

The Next Linear Collider Test Accelerator's RF Pulse Compression and Transmission Systems  

SciTech Connect

The overmoded rf transmission and pulsed power compression system for SLAC's Next Linear Collider (NLC) program requires a high degree of transmission efficiency and mode purity to be economically feasible. To this end, a number of new, high power components and systems have been developed at X-band, which transmit rf power in the low loss, circular TE01 mode with negligible mode conversion. In addition, a highly efficient SLED-II* pulse compressor has been developed and successfully tested at high power. The system produced a 200 MW, 250 ns wide pulse with a near-perfect flat-top. In this paper we describe the design and test results of the high power pulse compression system using SLED-II.

Tantawi, Sami.

1999-02-24

343

Cartography with accelerators: Locating fermions in extra dimensions at future lepton colliders  

SciTech Connect

In the model of Arkani-Hamed and Schmaltz the various chiral fermions of the standard model are localized at different points on a thick wall which forms an extra dimension. Such a scenario provides a way of understanding the absence of proton decay and the fermion mass hierarchy in models with extra dimensions. In this paper we explore the capability of future lepton colliders to determine the location of these fermions in the extra dimension through precision measurements of conventional scattering processes both below and on top of the lowest lying Kaluza-Klein gauge boson resonance. We show that for some classes of models the locations of these fermions can be very precisely determined while in others only their relative positions can be well measured.

Rizzo, Thomas G.

2001-07-01

344

The Next Linear Collider Test Accelerator's RF Pulse Compression and Transmission  

NASA Astrophysics Data System (ADS)

The overmoded rf transmission and pulsed power compression system for SLAC's Next Linear Collider (NLC) program requires a high degree of transmission efficiency and mode purity to be economically feasible. To this end, a number of new, high power components and systems have been developed at X-band, which transmit rf power in the low loss, circular TE_01 mode with negligible mode conversion. In addition, a highly efficient SLED-II^1 pulse compressor has been developed and successfully tested at high power. The system produced a 200 MW, 250 ns wide pulse with a near-perfect flat-top. In this paper we describe the design and test results of the high power pulse compression system using SLED-II. ^1P.B.Wilson, Z.D.Farkas, and R.D.Ruth, Linear Accel. Conf., Albuquerque, NM, Sept.'90; SLAC-PUB-5330.

Tantawi, S. G.; Adelphson, C.; Holmes, S.; Lavine, T.; Loewen, R. J.; Nantista, C.; Pearson, C.; Pope, R.; Rifkin, J.; Ruth, R. D.; Vlieks, A. E.

1997-05-01

345

A review of high beam current RFQ accelerators and funnels  

SciTech Connect

The authors review the design features of several high-current (> 20-mA) and high-power (> 1-mA average) proton or H{sup {minus}} injectors, RFQs, and funnels. They include a summary of observed performance and will mention a sampling of new designs, including the proposed incorporation of beam choppers. Different programs and organizations have chosen to build the RFQ in diverse configurations. Although the majority of RFQs are either low-current or very low duty-factor, several versions have included high-current and/or high-power designs for either protons or H{sup {minus}} ions. The challenges of cooling, handling high space-charge forces, and coupling with injectors and subsequent accelerators are significant. In all instances, beam tests were a valuable learning experience, because not always did these as-built structures perform exactly as predicted by the earlier design codes. They summarize the key operational parameters, indicate what was achieved, and highlight what was learned in these tests. Based on this generally good performance and high promise, even more challenging designs are being considered for new applications that include even higher powers, beam funnels and choppers.

Schneider, J.D.

1998-12-01

346

Beam transport design for a 1 MeV prototype dielectric wall accelerator  

NASA Astrophysics Data System (ADS)

The beam transport design of a novel proton dielectric wall accelerator is introduced in this paper. The protons will be accelerated from 40 keV to nearly 1 MeV under an accelerating gradient that is as high as 20 MV/m. A consideration of the beam line as well as the transport simulation is presented. The influences of the injection timing jitter and the accelerating pulse timing jitter are also discussed.

Zhu, Jun; Zhang, Huang; Peng, Shi-Xiang; Ren, Hai-Tao; Xia, Lian-Sheng; Wang, Wen-Dou; Yang, Zhi-Yong; Shen, Yi; Shi, Jin-Shui; Zhang, Lin-Wen; Deng, Jian-Jun

2014-04-01

347

Voltage holding study of 1 MeV accelerator for ITER neutral beam injector.  

PubMed

Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A?m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A?m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A?m(2)). PMID:22380278

Taniguchi, M; Kashiwagi, M; Umeda, N; Dairaku, M; Takemoto, J; Tobari, H; Tsuchida, K; Yamanaka, H; Watanabe, K; Kojima, A; Hanada, M; Sakamoto, K; Inoue, T

2012-02-01

348

First observations of beam losses due to bound-free pairproduction in a heavy-ion collider  

SciTech Connect

We report the first observations of beam losses due tobound-free pair production at the interaction point of a heavy-ioncollider. This process is expected to be a major luminosity limit for theLarge Hadron Collider (LHC) when it operates with 208Pb82+ ions becausethe localized energy deposition by the lost ions may quenchsuperconducting magnet coils. Measurements were performed at theRelativistic Heavy Ion Collider (RHIC) during operation with 100GeV/nucleon 63Cu29+ ions. At RHIC, the rate, energy and magnetic fieldare low enough so that magnet quenching is not an issue. The hadronicshowers produced when the single-electron ions struck the RHIC beampipewere observed using an array of photodiodes. The measurement confirms theorder of magnitude of the theoretical cross section previously calculatedby others.

Bruce, R.; Jowett, J.M.; Gilardoni, S.; Drees, A.; Fischer, W.; Tepikian, S.; Klein, S.R.

2007-06-15

349

International X-Band Linear Collider Accelerator Structure R&D  

Microsoft Academic Search

For more than fifteen years before the International Technology Recommendation Panel (ITRP) decision in August, 2004, there were intensive R&D activities and broad international collaboration among the groups at SLAC, KEK, FNAL, LLNL and other labs for the room temperature X-Band accelerator structures. The goal was to provide an optimized design of the main linac structure for the NLC (Next

J. W. Wang

2009-01-01

350

Fokusirovka ionnogo puchka s konechnym ehmittansom uskoryayushchej trubkoj ehlektrostaticheskogo uskoritelya. (Focusing of ion beam with limit emittance by accelerator tube of electrostatic accelerator).  

National Technical Information Service (NTIS)

Focusing of nonrelativistic ion beam with finite emittance by accelerator tube is considered. Analytical relation between positions of the entrance and exit crossovers as a function of the beam emittance and the accelerator tube parameters was obtained. T...

S. V. Bazhal V. A. Romanov

1994-01-01

351

Reconstruction of lattice parameters and beam momentum distribution from turn-by-turn beam position monitor readings in circular accelerators  

NASA Astrophysics Data System (ADS)

In high chromaticity circular accelerators, rapid decoherence of the betatron motion of a particle beam can make the measurement of lattice and bunch values, such as Courant-Snyder parameters and betatron amplitude, difficult. A method for reconstructing the momentum distribution of a beam from beam position measurements is presented. Further analysis of the same beam position monitor data allows estimates to be made of the Courant-Snyder parameters and the amplitude of coherent betatron oscillation of the beam. The methods are tested through application to data taken on the linear nonscaling fixed field alternating gradient accelerator, EMMA.

Edmonds, C. S.; Gratus, J.; Hock, K. M.; Machida, S.; Muratori, B. D.; Torromé, R. G.; Wolski, A.

2014-05-01

352

E-Beam Driven Accelerators Working Group Summary.  

National Technical Information Service (NTIS)

The working group has identified the parameters of an afterburner based on the design collider from 1 to 2 TeV. The afterburner is located in the final focus section of the collider, operates at a gradient of (approx)4 GeV/m, and is only about 125 m long....

P. Muggli

2005-01-01

353

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

SciTech Connect

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

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

2012-07-02

354

Li-beam-heated hohlraum experiments at Particle Beam Fusion Accelerator II  

SciTech Connect

Thermal radiation experiments with 9-MeV Li beams have been performed at Particle Beam Fusion Accelerator II with a peak beam intensity of 1{endash}2TW/cm{sup 2}. The peak brightness temperature of the target was 58{plus_minus}4eV. We obtained specific depositions of 800{endash}1600 TW/g in the foam. Important features of desired hohlraum performance have been demonstrated. These include a near-Planckian spectrum, increased heating due to the presence of a high-{ital Z} wall, x-ray mean free paths greater than the target size between 200 and 280 eV, thermal x-ray emission more uniform than the incident ion energy, and a high-{ital Z} wall velocity less than 3 cm/{mu}s. {copyright} {ital 1996 The American Physical Society.}

Derzon, M.S.; Chandler, G.A.; Dukart, R.J.; Johnson, D.J.; Leeper, R.J.; Matzen, M.K.; McGuire, E.J.; Mehlhorn, T.A.; Moats, A.R.; Olson, R.E.; Ruiz, C.L. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

1996-01-01

355

Particle acceleration fields derived from a wavefront-divided laser beam  

NASA Astrophysics Data System (ADS)

In a crossed-laser-beam linear accelerator, the longitudinal acceleration field is obtained by crossing two fundamental Gaussian laser beams with a ? phase difference from one another. We show by numerical calculation that a comparable acceleration field can be obtained by crossing two half-Gaussian laser beams wavefront-divided from a fundamental Gaussian laser beam. Since the relative phase between the two wavefront-divided, half-Gaussian beams is determined by a dielectric step at the splitting point, the ? relative phase can be preserved even though background acoustic noises are present.

Huang, Y. C.

1998-12-01

356

Transverse vibration and buckling of a cantilevered beam with tip body under axial acceleration  

Microsoft Academic Search

The transverse vibration and buckling of a cantilevered beam subject to constant axial acceleration with rigid tip body is investigated. Two classes of tip bodies are recognized: those with mass centers located along the beam tip tangent line, and those with mass centers having an arbitrary offset with respect to the beam attachment point (but not lying along the beam

J. Storch; S. Gates

1985-01-01

357

PREVENTING POLLUTION USING ISO 14001 AT A PARTICLE ACCELERATOR THE RELATIVISTIC HEAVY ION COLLIDER PROJECT  

Microsoft Academic Search

In early 1997 Brookhaven National Laboratory (BNL) discovered that the spent fuel pool of their High Flux Beam Reactor was leaking tritium into the groundwater. Community members, activist groups, politicians and regulators were outraged with the poor environmental management practices at BNL. The reactor was shut down and the Department of Energy (DOE) terminated the contract with the existing Management

S. L. K. BRIGGS; S. V. MUSOLINO

2001-01-01

358

Vaccine Biotechnology by Accelerated Electron Beam and Microwave Irradiation  

NASA Astrophysics Data System (ADS)

A new biotechnology for obtaining a commercial vaccine that contains either Fusobacterium necrophorum (F.n.) exotoxins inactivated by accelerated electron beam (EB) and microwave (MW) irradiation, or exotoxins isolated from F.n. cultures irradiated with EB+MW, is presented. This vaccine is designed for prophylaxis of ruminant infectious pododermatitis (IP) produced by F.n. Also, the research results concerning the effects of combined chemical adjuvant and EB+MW irradiation on F.n. immune capacity are discussed. The vaccine's efficacy will be tested in ruminant farms in which IP evolves. It is expected that this new vaccine to offer a better protection, more than 60%, which is the best presently obtained result in ruminant farms.

Craciun, Gabriela D.; Togoe, Iulian I.; Tudor, Laurentiu M.; Martin, Diana I.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.

2007-04-01

359

METHOD OF PRODUCING AND ACCELERATING AN ION BEAM  

NASA Technical Reports Server (NTRS)

A method of producing and accelerating an ion beam comprising the steps of providing a magnetic field with a cusp that opens in an outward direction along a centerline that passes through a vertex of the cusp: providing an ionizing gas that sprays outward through at least one capillary-like orifice in a plenum that is positioned such that the orifice is on the centerline in the cusp, outward of the vortex of the cusp; providing a cathode electron source, and positioning it outward of the orifice and off of the centerline; and positively charging the plenum relative to the cathode electron source such that the plenum functions as m anode. A hot filament may be used as the cathode electron source, and permanent magnets may be used to provide the magnetic field.

Foster, John E. (Inventor)

2005-01-01

360

Propagation of a beam halo in accelerator test facility 2 at KEK  

NASA Astrophysics Data System (ADS)

The beam halo is a major issue for interaction region (IR) backgrounds at many colliders, for example, future linear colliders, B factories, and also it is an important problem at ATF2. In this paper, we report on the halo propagation along the ATF2 beam line with realistic apertures, the nonlinear optics influence on the increasing number of halo particles input is analyzed, and the transmitted halo particles distribution just before the last BPM is then described, the results from which will benefit the Compton recoil electrons measurement.

Bai, Sha; Bambade, P.; Gao, Jie

2013-05-01

361

H-mode accelerating structures with PMQ focusing for low-beta ion beams  

SciTech Connect

We are developing high-efficiency normal-conducting RF accelerating structures based on inter-digital H-mode (IH) cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. Such IH-PMQ accelerating structures following a short RFQ can be used in the front end of ion linacs or in stand-alone applications, e.g. a compact deuteron-beam accelerator up to the energy of several MeV. Results of combined 3-D modeling for a full IH-PMQ accelerator tank - electromagnetic computations, beam-dynamics simulations with high currents, and thermal-stress analysis - are presented. The accelerating field profile in the tank is tuned to provide the best beam propagation using coupled iterations of electromagnetic and beam-dynamics modeling. A cold model of the IH-PMQ tank is being manufactured.

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

2010-01-01

362

Fluence and dose measurements for an accelerator neutron beam  

NASA Astrophysics Data System (ADS)

The 3 MV Van de Graaff accelerator at McMaster University accelerator laboratory is extended to a neutron irradiation facility for low-dose bystander effects research. A long counter and an Anderson-Braun type neutron monitor have been used as monitors for the determination of the total fluence. Activation foils were used to determine the thermal neutron fluence rate (around 10 6 neutrons s -1). Meanwhile, the interactions of neutrons with the monitors have been simulated using a Monte Carlo N Particle (MCNP) code. Bystander effects, i.e. damage occurring in cells that were not traversed by radiation but were in the same radiation environment, have been well observed following both alpha and gamma irradiation of many cell lines. Since neutron radiation involves mixed field (including gamma and neutron radiations), we need to differentiate the doses for the bystander effects from the two radiations. A tissue equivalent proportional counter (TEPC) filled with propane based tissue equivalent gas simulating a 2 ?m diameter tissue sphere has been investigated to estimate the neutron and gamma absorbed doses. A photon dose contamination of the neutron beam is less than 3%. The axial dose distribution follows the inverse square law and lateral and vertical dose distributions are relatively uniform over the irradiation area required by the biological study.

Liu, Z.; Byun, S. H.; McNeill, F. E.; Mothersill, C. E.; Seymour, C. B.; Prestwich, W. V.

2007-10-01

363

Education in a rapidly advancing technology: Accelerators and beams  

NASA Astrophysics Data System (ADS)

The field of accelerators and beams (A&B) is one of today's fast changing technologies. Because university faculties have not been able to keep pace with the associated advancing knowledge, universities have not been able to play their traditional role of educating the scientists and engineers needed to sustain this technology for use in science, industry, commerce, and defense. This problem for A&B is described and addressed. The solution proposed, a type of ``distance'' education, is the U.S. Particle Accelerator School (USPAS) created in the early 1980s. USPAS provides the universities with a means of serving the education needs of the institutions using A&B, primarily but not exclusively the national laboratories. The field of A&B is briefly summarized. The need for education outside the university framework, the raison d'être for USPAS, the USPAS method, program structure, and curriculum, and particular USPAS-university connections are explained. The management of USPAS is analyzed, including its unique administrative structure, its institutional ties, and its operations, finance, marketing, and governmental relations. USPAS performance over the years is documented and a business assessment is made. Finally, there is a brief discussion of the future potential for this type of educational program, including possible extrapolation to new areas and/or different environments, in particular, its extra-government potential and its international possibilities.

Month, Mel

2000-06-01

364

Muon Collider  

SciTech Connect

Parameters are given of muon colliders with center of mass energies of 1.5 and 3 TeV. Pion production is from protons on a mercury target. Capture, decay, and phase rotation yields bunch trains of both muon signs. Six dimensional cooling reduces the emittances until the trains are merged into single bunches, one of each sign. Further cooling in 6 dimensions is then applied, followed by final transverse cooling in 50 T solenoids. After acceleration the muons enter the collider ring. Ongoing R&D is discussed.

Palmer, R.

2009-10-19

365

Beam Dynamics in a Linear Accelerator for Generations of Short Electron Beams and Femtosecond Hard X-ray Pulses  

NASA Astrophysics Data System (ADS)

We investigate a linear accelerator system capable of generating short electron beams and femtosecond hard X-ray pulses. We show a detailed design for a two-stage bunch compressor to generate the short electron beams in the linear accelerator. The bunch compressor system consists of two chicanes with a short system length that can compress an electron bunch of 0.6 nC and beam energy of 162 MeV, from 3 to 0.5 ps rms. One important design issue in the bunch compressor is to make as small growths of the emittance and energy spread as possible. The normalized horizontal emittance of 3 mm mrad is increased by approximately 10% due to coherent synchrotron radiation in the designed bunch compressor. Lattice distortions due to machine errors associate with quadrupole magnets, bending magnets and beam position monitors in the linear accelerator were investigated. It is shown that the lattice distortions due to the machine errors can be easily compensated by performing both orbit correction and dispersion correction in the linear accelerator. We have performed tolerance studies due to the various jitter sources in the linear accelerator to examine their sensitivities on the beam quality. From these results, it is shown that the linear accelerator system provides sufficient tolerances to maintain stable electron beams. We also investigated the generation of femtosecond hard X-ray pulses that may be provided by the interactions at 90\\circ of the short electron beams in the linear accelerator with a laser system. It is shown that 3.4× 106 photons within 10% bandwidth at 0.04 Å wavelength in about 350 fs rms pulse may be provided using the linear accelerator system. We presented studies on beam dynamics in the linear accelerator system that may provide the short beams and intense X-ray pulses.

Kim, Eun-San

2007-12-01

366

Interaction of a 24 GeV Proton Beam with a Muon Collider Mercury Jet Target Experimental Results and Thermodynamic Assessment.  

National Technical Information Service (NTIS)

A muon collider or a neutrino factory based on a muon storage ring require intense beams of muons that can be generated by a 1-4 MW proton beam incident on a moving target inside a 20-T solenoid magnet, with a mercury jet as a prefemed example. This paper...

N. Simos H. Kirk C. Finfrock G. Greens H. Ludwig K. McDonald N. Mokhov

2002-01-01

367

Accelerated partial breast irradiation using proton beams: Initial dosimetric experience  

SciTech Connect

Purpose: The unique dosimetric features of proton radiotherapy make it an attractive modality for normal tissue sparing. We present our initial experience with protons for three-dimensional, conformal, external-beam accelerated partial breast irradiation (3D-CPBI). Methods and Materials: From March 2004 to June 2005, 25 patients with tumors {<=}2 cm and negative axillary nodes were treated with proton 3D-CPBI. The prescribed dose was 32 Cobalt Gray Equivalents (CGE) in 4 CGE fractions given twice daily. One to three fields were used to provide adequate planning target volume (PTV) coverage and dose homogeneity. Results: Excellent PTV coverage and dose homogeneity were obtained in all patients with one to three proton beams. The median PTV receiving 95% of the prescribed dose was 100%. Dose inhomogeneity exceeded 10% in only 1 patient (4%). The median volume of nontarget breast tissue receiving 50% of the prescribed dose was 23%. Median volumes of ipsilateral lung receiving 20 CGE, 10 CGE, and 5 CGE were 0%, 1%, and 2%, respectively. The contralateral lung and heart received essentially no radiation dose. Cost analysis suggests that proton 3D-CPBI is only modestly more expensive (25%) than traditional whole-breast irradiation (WBI). Conclusion: Proton 3D-CPBI is technically feasible, providing both excellent PTV coverage and normal tissue sparing. It markedly reduces the volume of nontarget breast tissue irradiated compared with photon-based 3D-CPBI, addressing a principle disadvantage of external-beam approaches to PBI. As proton therapy becomes more widely available, it may prove an attractive tool for 3D-CPBI.

Taghian, Alphonse G. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)]. E-mail: ataghian@partners.org; Kozak, Kevin R. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Katz, Angela [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Adams, Judith C. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Lu, H.-M. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Powell, Simon N. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); DeLaney, Thomas F. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

2006-08-01

368

Design of a synchrotron radiation detector for the test beam lines at the Superconducting Super Collider Laboratory  

SciTech Connect

As part of the particle- and momentum-tagging instrumentation required for the test beam lines of the Superconducting Super Collider (SSC), the synchrotron radiation detector (SRD) was designed to provide electron tagging at momentum above 75 GeV. In a parallel effort to the three test beam lines at the SSC, schedule demands required testing and calibration operations to be initiated at Fermilab. Synchrotron radiation detectors also were to be installed in the NM and MW beam lines at Femilab before the test beam lines at the SSC would become operational. The SRD is the last instrument in a series of three used in the SSC test beam fines. It follows a 20-m drift section of beam tube downstream of the last silicon strip detector. A bending dipole just in of the last silicon strip detector produces the synchrotron radiation that is detected in a 50-mm-square cross section NaI crystal. A secondary scintillator made of Bicron BC-400 plastic is used to discriminate whether it is synchrotron radiation or a stray particle that causes the triggering of the NaI crystal`s photo multiplier tube (PMT).

Hutton, R.D.

1994-01-01

369

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

DOEpatents

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

Maschke, Alfred W. (East Moriches, NY)

1983-07-05

370

Fermilab Collider: Performance and plans  

SciTech Connect

The Fermilab collider program has completed its first physics run with two major detectors, CDF and DO. Recent performance of the Fermilab accelerator complex during Run Ia is presented, along with plans to improve the luminosity of the collider. The beam-beam tune shift limitations of previous runs have been avoided by the successful implementation of electrostatic separators in the Tevatron. The simultaneous operation of two high luminosity sections is provided by two matched low beta inserts. The Antiproton Source has increased its performance over the previous run as measured by stack size and stacking rate. The Linac will be upgraded from 200 MeV to 400 MeV in order to lessen the space charge tune shift upon injection into the Booster and provide proton beams with increased intensity with the same emittance. Higher luminosity requires more bunches in the Tevatron to again avoid the limitation due to the beam-beam interaction. Until it is replaced with the Main Injector, the Main Ring will remain as the most significant bottleneck on the performance of the collider.

Finley, D.A.

1993-12-01

371

External-Beam Accelerated Partial Breast Irradiation Using Multiple Proton Beam Configurations  

SciTech Connect

Purpose: To explore multiple proton beam configurations for optimizing dosimetry and minimizing uncertainties for accelerated partial breast irradiation (APBI) and to compare the dosimetry of proton with that of photon radiotherapy for treatment of the same clinical volumes. Methods and Materials: Proton treatment plans were created for 11 sequential patients treated with three-dimensional radiotherapy (3DCRT) photon APBI using passive scattering proton beams (PSPB) and were compared with clinically treated 3DCRT photon plans. Monte Carlo calculations were used to verify the accuracy of the proton dose calculation from the treatment planning system. The impact of range, motion, and setup uncertainty was evaluated with tangential vs. en face beams. Results: Compared with 3DCRT photons, the absolute reduction of the mean of V100 (the volume receiving 100% of prescription dose), V90, V75, V50, and V20 for normal breast using protons are 3.4%, 8.6%, 11.8%, 17.9%, and 23.6%, respectively. For breast skin, with the similar V90 as 3DCRT photons, the proton plan significantly reduced V75, V50, V30, and V10. The proton plan also significantly reduced the dose to the lung and heart. Dose distributions from Monte Carlo simulations demonstrated minimal deviation from the treatment planning system. The tangential beam configuration showed significantly less dose fluctuation in the chest wall region but was more vulnerable to respiratory motion than that for the en face beams. Worst-case analysis demonstrated the robustness of designed proton beams with range and patient setup uncertainties. Conclusions: APBI using multiple proton beams spares significantly more normal tissue, including nontarget breast and breast skin, than 3DCRT using photons. It is robust, considering the range and patient setup uncertainties.

Wang Xiaochun; Amos, Richard A.; Zhang Xiaodong; Taddei, Phillip J. [Departments of Radiation Physics and Radiation Oncology, University of Texas, M. D. Anderson Cancer Center, Houston, TX (United States); Woodward, Wendy A., E-mail: wwoodward@mdanderson.org [Departments of Radiation Physics and Radiation Oncology, University of Texas, M. D. Anderson Cancer Center, Houston, TX (United States); Hoffman, Karen E.; Yu, Tse Kuan; Tereffe, Welela; Oh, Julia; Perkins, George H.; Salehpour, Mohammad; Zhang, Sean X.; Sun, Tzou Liang; Gillin, Michael; Buchholz, Thomas A.; Strom, Eric A. [Departments of Radiation Physics and Radiation Oncology, University of Texas, M. D. Anderson Cancer Center, Houston, TX (United States)

2011-08-01

372

Drive Beam Shaping and Witness Bunch Generation for the Plasma Wakefield Accelerator  

SciTech Connect

High transformer ratio operation of the plasma wake field accelerator requires a tailored drive beam current profile followed by a short witness bunch. We discuss techniques for generating the requisite dual bunches and for obtaining the desired drive beam profile, with emphasis on the FACET experiment at SLAC National Accelerator Laboratory.

England, R. J.; Frederico, J.; Hogan, M. J. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Muggli, P. [University of Southern California, Los Angeles, CA 90089 (United States); Joshi, C. [University of California Los Angeles, Los Angeles, CA 90024 (United States)

2010-11-04

373

Drive Beam Shaping and Witness Bunch Generation for the Plasma Wakefield Accelerator  

NASA Astrophysics Data System (ADS)

High transformer ratio operation of the plasma wake field accelerator requires a tailored drive beam current profile followed by a short witness bunch. We discuss techniques for generating the requisite dual bunches and for obtaining the desired drive beam profile, with emphasis on the FACET experiment at SLAC National Accelerator Laboratory.

England, R. J.; Frederico, J.; Hogan, M. J.; Muggli, P.; Joshi, C.

2010-11-01

374

Drive Beam Shaping and Witness Bunch Generation for the Plasma Wakefield Accelerator  

Microsoft Academic Search

High transformer ratio operation of the plasma wake field accelerator requires a tailored drive beam current profile followed by a short witness bunch. We discuss techniques for generating the requisite dual bunches and for obtaining the desired drive beam profile, with emphasis on the FACET experiment at SLAC National Accelerator Laboratory.

R. J. England; J. Frederico; M. J. Hogan; P. Muggli; C. Joshi

2010-01-01

375

The Next Linear Collider Test Accelerator's RF Pulse Compression And Transmission  

SciTech Connect

The overmoded rf transmission and pulsed power compression system for SLAC's Next Linear Collider (NLC) program requires a high degree of transmission efficiency and mode purity to be economically feasible. To this end, a number of new, high power components and systems have been developed at X-band, which transmit rf power in the low loss, circular TE01 mode with negligible mode conversion. In addition, a highly efficient SLED-II* pulse compressor has been developed and successfully tested at high power. The system produced a 200 MW, 250 ns wide pulse with a near-perfect flat-top. In this paper we describe the design and test results of the high power pulse compression system using SLED-II. The NLC rf systems use low loss highly over-moded circular waveguides operating in the TE01 mode. The efficiency of the systems is sensitive to the mode purity of the mode excited inside these guides. We used the so called flower petal mode transducer [2] to excite the TE01 mode. This type of mode transducer is efficient, compact and capable of handling high levels of power. To make more efficient systems, we modified this device by adding several mode selective chokes to act as mode purifiers. To manipulate the rf signals we used these modified mode converters to convert back and forth between over-moded circular waveguides and single-moded WR90 rectangular waveguides. Then, we used the relatively simple rectangular waveguide components to do the actual manipulation of rf signals. For example, two mode transducers and a mitered rectangular waveguide bend comprise a 90 degree bend. Also, a magic tee and four mode transducers would comprise a four-port-hybrid, etc. We will discuss the efficiency of an rf transport system based on the above methodology. We also used this methodology in building the SLEDII pulse compression system. At SLAC we built 4 of these pulse systems. In this paper we describe the SLEDII system and compare the performance of these 4 systems at SLAC. We report the experimental procedures used to measure their performance as well as the results of high power tests.

Tantawi, S.G.; Adelphson, C.; Holmes, S.; Lavine, Theodore L.; Loewen, R.J.; Nantista, C.; Pearson, C.; Pope, R.; Rifkin, J.; Ruth, R.D.; Vlieks, A.E.; /SLAC

2011-09-14

376

High energy acceleration of H{sup {minus}} ion beam at MeV test facility  

SciTech Connect

MeV test facility was constructed for proof-of-principle test of 1 MeV, 1 A class negative ion beam acceleration. The dimensions of the ion source/accelerator is 2 m in diameter and 1.9 m in height. The H{sup {minus}} ions were produced in a KAMABOKO shaped volume production type negative ion source, and extracted through 49 apertures of 14 mm in diameter. The accelerator is a five-stage electrostatic accelerator with insulator columns made of fiber reinforced plastic (FRP). The accelerator was conditioned to hold the voltage up to 760 kV without beam. Then the H{sup {minus}} ion beams of 0.23 A (drain current) were successfully accelerated up to 700 keV for 1 s. Degradation of voltage holding characteristics was not observed with/without the beam at this level of the current and energy. {copyright} {ital 1996 American Institute of Physics.}

Inoue, T.; Fujiwara, Y.; Miyamoto, K.; Miyamoto, N.; Nagase, A.; Ohara, Y.; Okumura, Y.; Watanabe, K.; Yokoyama, K. [Japan Atomic Energy Research Institute, Naka, Naka-machi, Naka-gun, Ibaraki-ken 311-01 (Japan)

1996-07-01

377

Steel tape-wound cut cores as magnet yokes for the beam-dump kickers of the Large Hadron Collider  

Microsoft Academic Search

Fast-pulsed magnets, also called kickers, are used in particle accelerators for beam injection, extraction and similar applications. To excite these magnets, typically current pulses with rise and fall times in the range of 100 ns to 10 ?s are used, with a pulse duration of up to 100 ?s and amplitudes in the order of kilo amperes. The short rise

M. Mayer; D. Fox; F. Castronuovo; U. Jansson

2004-01-01

378

Reverse Emittance Exchange for Muon Colliders  

SciTech Connect

Muon collider luminosity depends on the number of muons in the storage ring and on the transverse size of the beams in collision. Ionization cooling as it is currently envisioned will not cool the beam sizes sufficiently well to provide adequate luminosity without large muon intensities. Six-dimensional cooling schemes will reduce the longitudinal emittance of a muon beam so that smaller high frequency RF cavities can be used for later stages of cooling and for acceleration. However, the bunch length at collision energy is then shorter than needed to match the interaction region beta function. New ideas to shrink transverse beam dimensions by lengthening each bunch will help achieve high luminosity in muon colliders. Analytic expressions for the reverse emittance exchange mechanism were derived, including a new resonant method of beam focusing.

V. Ivanov, A. Afanasev, C.M. Ankenbrandt, R.P. Johnson, G.M. Wang, S.A. Bogacz, Y.S. Derbenev

2009-05-01

379

Energy Amplification and Beam Bunching in a Pulse Line Ion Accelerator  

SciTech Connect

In a first beam dynamics validation experiment for a new Pulse Line Ion Acceleration (PLIA) concept, the predicted energy amplification and beam bunching were experimentally observed. Beam energy modulation of -80 keV to +150 keV was measured using a PLIA input voltage waveform of -21 kV to +12 kV. Ion pulses accelerated by 150 keV, and bunching by a factor of four were simultaneously achieved. The measured longitudinal phase space and current waveform of the accelerated beam are in good agreement with 3-D particle-in-cell simulations.

Roy, P K; Waldron, W L; Yu, S S; Coleman, J E; Henestroza, E; Grote, D P; Baca, D; Bieniosek, F M; Briggs, R J; Davidson, R C; Eylon, S; Friedman, A; Greenway, W G; Leitner, M; Logan, G B; Reginato, L L; Seidl, P A

2006-06-08

380

Proceedings of the international workshop on next-generation linear colliders  

SciTech Connect

This report contains papers on the next-generation of linear colliders. The particular areas of discussion are: parameters; beam dynamics and wakefields; damping rings and sources; rf power sources; accelerator structures; instrumentation; final focus; and review of beam-beam interaction.

Riordan, M. (ed.)

1988-12-01

381

Solvable model of beam-beam effects in e/sup +/e/sup -/ colliding storage rings  

SciTech Connect

A solvable model is constructed for the strong-beam--strong-beam phenomenon. The model represents the extreme case where the radiation effect is quite strong. Although it does not present a quantitatively accurate description of the beam behavior for realistic ring parameters, it qualitatively well illustrates several common characteristic features of the observed phenomenon: saturation of the beam-beam parameter, universality of its saturated value, blowup of one of the beams (spontaneous symmetry breakdown), flip-flop hysteresis (cusp catastrophe), and so on.

Hirata, K.

1988-03-01

382

Low emittance electron beam generation from a laser wakefield accelerator using two laser pulses with different wavelengths  

NASA Astrophysics Data System (ADS)

Ionization injection triggered by short wavelength laser pulses inside a nonlinear wakefield driven by a longer wavelength laser is examined via multidimensional particle-in-cell simulations. We find that very bright electron beams can be generated through this two-color scheme in either collinear propagating or transverse colliding geometry. For a fixed laser intensity I, lasers with longer/shorter wavelength ? have larger/smaller ponderomotive potential (?I ?2). The two-color scheme utilizes this property to separate the injection process from the wakefield excitation process. Very strong wakes can be generated at relatively low laser intensities by using a longer wavelength laser driver (e.g., a 10 ?m CO2 laser) due to its very large ponderomotive potential. On the other hand, a short wavelength laser can produce electrons with very small residual momenta (p ? ˜a0˜?I ?) inside the wake, leading to electron beams with very small normalized emittances (tens of nm). Using particle-in-cell simulations we show that a ˜10 fs electron beam with ˜4 pC of charge and a normalized emittance of ˜50 nm can be generated by combining a 10 ?m driving laser with a 400 nm injection laser, which is an improvement of more than 1 order of magnitude compared to the typical results obtained when a single wavelength laser is used for both the wake formation and ionization injection. With the transverse colliding geometry, simulations show that similarly low emittance and much lower slice energy spread (˜30 keV, comparing with the typical value of few MeV in the longitudinal injection scheme) can be simultaneously obtained for electron beams with a few pC charge. Such low slice energy spread may have significant advantages in applications relevant to future coherent light sources driven by plasma accelerators.

Xu, X. L.; Wu, Y. P.; Zhang, C. J.; Li, F.; Wan, Y.; Hua, J. F.; Pai, C.-H.; Lu, W.; Yu, P.; Joshi, C.; Mori, W. B.

2014-06-01

383

Acceleration of positrons by a relativistic electron beam in the presence of quantum effects  

SciTech Connect

Using the quantum magnetohydrodynamic model and obtaining the dispersion relation of the Cherenkov and cyclotron waves, the acceleration of positrons by a relativistic electron beam is investigated. The Cherenkov and cyclotron acceleration mechanisms of positrons are compared together. It is shown that growth rate and, therefore, the acceleration of positrons can be increased in the presence of quantum effects.

Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)] [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Aki, H.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)] [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)

2013-09-15

384

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

SciTech Connect

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

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

1993-11-01

385

Flash X-Ray (FXR) Accelerator Optimization Beam-Induced Voltage Simulation and TDR Measurements  

Microsoft Academic Search

Lawrence Livermore National Laboratory (LLNL) is evaluating design alternatives to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell and pulse-power system. The goal is to create a more mono-energetic electron beam. When an electron beam crosses the energized gap of an accelerator cell, the electron energy is increased. However, the beam with the associated electromagnetic wave also

M. M. Ong; G. E. Vogtlin

2005-01-01

386

Improvement of voltage holding and high current beam acceleration by MeV accelerator for ITER NB  

SciTech Connect

Voltage holding of -1 MV is an essential issue in development of a multi-aperture multi-grid (MAMuG) negative ion accelerator, of which target is to accelerate 200 A/m{sup 2} H{sup -} ion beam up to the energy of 1 MeV for several tens seconds. Review of voltage holding results ever obtained with various geometries of the accelerators showed that the voltage holding capability was about a half of designed value based on the experiment obtained from ideal small electrode. This is considered due to local electric field concentration in the accelerators, such as edge and steps between multi-aperture grids and its support structures. Based on the detailed investigation with electric field analysis, accelerator was modified to reduce the electric field concentration by reshaping the support structures and expanding the gap length between the grid supports. After the modifications, the accelerator succeeded in sustaining -1 MV for more than one hour in vacuum. Improvement of the voltage holding characteristics progressed the energy and current accelerated by the MeV accelerator. Up to 2010, beam parameters achieved by the MAMuG accelerator were increased to 879 keV, 0.36 A (157 A/m{sup 2}) at perveance matched condition and 937 keV, 0.33 A (144 A/m{sup 2}) slightly under perveance.

Taniguchi, M.; Kashiwagi, M.; Inoue, T.; Umeda, N.; Watanabe, K.; Tobari, H.; Dairaku, M.; Yamanaka, H.; Tsuchida, K.; Kojima, A.; Hanada, M.; Sakamoto, K. [Japan Atomic Energy Agency, Naka Fusion Research Establishment, 801-1 Mukoyama, Naka, 311-0193 (Japan)

2011-09-26

387

Conceptual design of the Relativistic Heavy Ion Collider: RHIC  

SciTech Connect

The complete Relativistic Heavy Ion Collider (RHIC) facility will be a complex set of accelerators and beam transfer equipment connecting them. A significant portion of the total facility either exists or is under construction. Two existing Tandem Van de Graaff accelerators will serve for the initial ion acceleration. Ions with a charge of -1 would be accelerated from ground to +15 MV potential, pass through a stripping foil, and accelerate back to ground potential, where they would pass through a second stripping foil. From there the ions will traverse a long transfer line to the AGS tunnel and be injected into the Booster accelerator. The Booster accelerates the ion bunch, and then the ions pass through one more stripper and then enter the Alternating Gradient Synchrotron (AGS), where they are accelerated to the top AGS energy and transferred to the collider. Bending and focusing of ion beams is to be achieved by superconducting magnets. The physics goals behind the RHIC are enumerated, particularly as regards the study of quark matter and the characteristics of high energy nucleus-nucleus collisions. The design of the collider and all its components is described, including the injector, the lattice, magnet system, cryogenic and vacuum systems, beam transfer, injection, and dump, rf system, and beam instrumentation and control system. Also given are cost estimates, construction schedules, and a management plan. (LEW)

Not Available

1986-05-01

388

Observation of Electron Cloud Stabilized 1 MeV Beam-Beam d+d Reactons in Self-Colliding Orbits and Feasibility of Electric Isotope Breeder  

NASA Astrophysics Data System (ADS)

D-D Self-Collider ^1,2 is only system in which beam-beam nuclear reactions demonstrated MeV energies. 1.45 MeV DC beam of D2^+ was injected into center of a weak-focusing magnetic field (Ni Ti) B=3.12 Tesla, and dissociated into 2 d^+ stored in Self-Colliding Orbits^3. Energy confinement time T = 23 s (vacuum limited p=10-9 torr), stabilized by driven electron oscillations^4. A simulation^5 shows that 1 DD neutron is produced at an energy cost of 5.36 MeV/n i.e. 140 MWh/g= 8,360/g vs. 160,000/g from beam - target. Simultaneously produced He^3 and T are not only free, but bring 45 fold gain. 5 d's of 0.75 MeV generate 1He^3 +1T +1p+ 1n at cost 5.36 MeV. Hence, it will produce 2 He^3 nuclei (1 He-3, 1 T) plus energy gain of 161 MeV. This will be reduced by the energy gain thus reducing cost to 4.5 from 5.6 MeV. Assumed ion density 5x10 ^14 was achieved in plasmas. Beam injection 100 mA. 1. PRL 54, 796 (1985) NIM A 271 p,.1-167; 2. AIP CP 311, 292 (93); 3. PRL 70, 1818 (93); 4.Part. Acc.1, (70); 5. ``50 Years with Fission'' Symp.Nat. Ac Sci., p. 761 (89)

Maglich, Bogdan; Druey, Christian; Iyengar, P. K.; Srinivasan, Mahadeva

2012-03-01

389

Generation of Optical Accelerating Quinary-Cusp Beams and Their Optical Characteristics  

NASA Astrophysics Data System (ADS)

By designing pivotal phase-only masks based on canonical catastrophe theory, finite-energy optical quinary-cusp beams are experimentally generated for the first time. Such beams are a kind of new accelerating beams having five sampling points. Their optical topological structures and propagation characteristics are investigated subsequently. Moreover, we also find that the acceleration of quinary-cusp beams can be controlled by changing the Fourier transform lens with the different local lengths. Such research results are believed to pave the way toward future potential scientific applications of quinary-cusp beams.

Ren, Zhi-Jun; Li, Xiao-Dong; Fan, Chang-Jiang; Xu, Zhuo-Qi

2013-11-01

390

Observation of self-accelerating Bessel-like optical beams along arbitrary trajectories.  

PubMed

We experimentally demonstrate self-accelerating Bessel-like optical beams propagating along arbitrary trajectories in free space. With computer-generated holography, such beams are designed to follow different controllable trajectories while their main lobe transverse profiles remain nearly invariant and symmetric. Examples include parabolic, snake-like, hyperbolic, hyperbolic secant, and even three-dimensional spiraling trajectories. The self-healing property of such beams is also demonstrated. This new class of optical beams can be considered as a hybrid between accelerating and nonaccelerating nondiffracting beams that may find a variety of applications. PMID:23455115

Zhao, Juanying; Zhang, Peng; Deng, Dongmei; Liu, Jingjiao; Gao, Yuanmei; Chremmos, Ioannis D; Efremidis, Nikolaos K; Christodoulides, Demetrios N; Chen, Zhigang

2013-02-15

391

Center for Beam Physics papers  

SciTech Connect

Six papers are included in this collection. They cover: a second interaction region for gamma-gamma, gamma-electron and electron- electron collisions; constraints on laser-driven accelerators for a high-energy linear collider; progress on the design of a high luminosity muon-muon collider; RF power source development at the RTA test facility; sensitivity studies of crystalline beams; and single bunch collective effects in muon colliders.

Sessler, A.M. [ed.

1996-06-01

392

Focusing of Submicron Beams for TeV-Scale e+e- Linear Colliders  

NASA Astrophysics Data System (ADS)

First experimental results from the final focus test beam (FFTB) are reported. The vertical dimension of a 47-GeV electron beam from the SLAC linac has been reduced at the focal point of the FFTB by a demagnification of 320 to a beam height of approximately 70 nm.

Balakin, V.; Alexandrov, V. A.; Mikhailichenko, A.; Flöttmann, K.; Peters, F.; Voss, G.-A.; Bharadwaj, V.; Halling, M.; Holt, J. A.; Buon, J.; Jeanjean, J.; Lediberder, F.; Lepeltier, V.; Puzo, P.; Heimlinger, G.; Settles, R.; Stierlin, U.; Hayano, H.; Ishihara, N.; Nakayama, H.; Oide, K.; Shintake, T.; Takeuchi, Y.; Yamamoto, N.; Bulos, F.; Burke, D.; Field, R.; Hartman, S.; Helm, R.; Irwin, J.; Iverson, R.; Rokni, S.; Roy, G.; Spence, W.; Tenenbaum, P.; Wagner, S. R.; Walz, D.; Williams, S.

1995-03-01

393

Dosimetric characteristics of electron beams produced by a mobile accelerator for IORT  

Microsoft Academic Search

Energy and angular distributions of electron beams with different energies were simulated by Monte Carlo calculations. These beams were generated by the NOVAC7 system (Hitesys, Italy), a mobile electron accelerator specifically dedicated to intra-operative radiation therapy (IORT). The electron beam simulations were verified by comparing the measured dose distributions with the corresponding calculated distributions. As expected, a considerable difference was

M Pimpinella; D Mihailescu; A S Guerra; R F Laitano

2007-01-01

394

Dosimetric characteristics of electron beams produced by a mobile accelerator for IORT  

Microsoft Academic Search

Energy and angular distributions of electron beams with different energies were simulated by Monte Carlo calculations. These beams were generated by the NOVAC7® system (Hitesys, Italy), a mobile electron accelerator specifically dedicated to intra-operative radiation therapy (IORT). The electron beam simulations were verified by comparing the measured dose distributions with the corresponding calculated distributions. As expected, a considerable difference was

M. Pimpinella; D. Mihailescu; A. S. Guerra; R. F. Laitano

2007-01-01

395

Numerical Modelling of Intense Electron Beam Transport in the Spiral Line Induction Accelerator.  

National Technical Information Service (NTIS)

Computer simulation is used to study issues of intense electron beam transport arising in the context of the spiral line induction accelerator (SLIA), a device in which the beam is transported along an open-ended beam pipe, making multiple passes through ...

J. Krall S. Slinker M. Lampe G. Joyce

1992-01-01

396

Coupled longitudinal-transverse dynamics of an axially accelerating beam  

NASA Astrophysics Data System (ADS)

The coupled longitudinal-transverse nonlinear dynamics of an axially accelerating beam is numerically investigated; this problem is classified as a parametrically excited gyroscopic system. The axial speed is assumed to be comprised of a constant mean value along with harmonic fluctuations. Hamilton's principle is employed to derive the equations of motion of the system which are in the form of two coupled partial differential equations. The equations are discretized using the Galerkin method, which yields a set of coupled second-order nonlinear ordinary differential equations with time-dependent coefficients. The sub-critical dynamics of the system is examined via the pseudo-arclength continuation technique, while the global dynamics is investigated using direct time integration. The mean axial speed and the amplitude of the speed variations are varied so as to construct the bifurcation diagrams of Poincaré maps. The vibration specifications of the system are investigated more detailed via plotting time histories, phase-plane portraits, and fast Fourier transforms (FFTs).

Ghayesh, Mergen H.

2012-11-01

397

Studies of pear-shaped nuclei using accelerated radioactive beams.  

PubMed

There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are 'octupole deformed', that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on (220)Rn and (224)Ra show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental studies of atomic electric-dipole moments that might reveal extensions to the standard model. PMID:23657348

Gaffney, L P; Butler, P A; Scheck, M; Hayes, A B; Wenander, F; Albers, M; Bastin, B; Bauer, C; Blazhev, A; Bönig, S; Bree, N; Cederkäll, J; Chupp, T; Cline, D; Cocolios, T E; Davinson, T; De Witte, H; Diriken, J; Grahn, T; Herzan, A; Huyse, M; Jenkins, D G; Joss, D T; Kesteloot, N; Konki, J; Kowalczyk, M; Kröll, Th; Kwan, E; Lutter, R; Moschner, K; Napiorkowski, P; Pakarinen, J; Pfeiffer, M; Radeck, D; Reiter, P; Reynders, K; Rigby, S V; Robledo, L M; Rudigier, M; Sambi, S; Seidlitz, M; Siebeck, B; Stora, T; Thoele, P; Van Duppen, P; Vermeulen, M J; von Schmid, M; Voulot, D; Warr, N; Wimmer, K; Wrzosek-Lipska, K; Wu, C Y; Zielinska, M

2013-05-01

398

Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC  

ScienceCinema

Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

Andrei Seryi

2010-01-08

399

Voltage holding study of 1 MeV accelerator for ITER neutral beam injector  

SciTech Connect

Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A/m{sup 2} (346 mA) where the 3 x 5 apertures were used. Measurement of the beam profile revealed that deflection of the H{sup -} ions was large and a part of the H{sup -} ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A/m{sup 2} (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A/m{sup 2}).

Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Dairaku, M.; Takemoto, J.; Tobari, H.; Tsuchida, K.; Yamanaka, H.; Watanabe, K.; Kojima, A.; Hanada, M.; Sakamoto, K.; Inoue, T. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

2012-02-15

400

Observation of accelerating Wannier-Stark beams in optically induced photonic lattices.  

PubMed

We generate optical beams analogous to the Wannier-Stark states in semiconductor superlattices and observe that the two main lobes of the WS beams self-bend (accelerate) along two opposite trajectories in a uniform one-dimensional photonic lattice. Such self-accelerating features exist only in the presence of the lattice and are not observed in a homogenous medium. Under the action of nonlinearity, however, the beam structure and acceleration cannot be preserved. Our experimental observations are in qualitative agreement with theoretical predictions. PMID:24562279

Qi, Xinyuan; Makris, Konstantinos G; El-Ganainy, Ramy; Zhang, Peng; Bai, Jintao; Christodoulides, Demetrios N; Chen, Zhigang

2014-02-15

401

Recent Advances in Plasma Acceleration  

SciTech Connect

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

Hogan, Mark

2007-03-19

402

Beam loading in a laser-plasma accelerator using a near-hollow plasma channel  

SciTech Connect

Beam loading in laser-plasma accelerators using a near-hollow plasma channel is examined in the linear wake regime. It is shown that, by properly shaping and phasing the witness particle beam, high-gradient acceleration can be achieved with high-efficiency, and without induced energy spread or emittance growth. Both electron and positron beams can be accelerated in this plasma channel geometry. Matched propagation of electron beams can be achieved by the focusing force provided by the channel density. For positron beams, matched propagation can be achieved in a hollow plasma channel with external focusing. The efficiency of energy transfer from the wake to a witness beam is calculated for single ultra-short bunches and bunch trains.

Schroeder, C. B.; Benedetti, C.; Esarey, E.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2013-12-15

403

Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider  

SciTech Connect

The concept of augmenting the conventional collimation system of high-energy storage rings with a hollow electron beam was successfully demonstrated in experiments at the Tevatron. A reliable numerical model is required for understanding particle dynamics in the presence of a hollow beam collimator. Several models were developed to describe imperfections of the electron beam profile and alignment. The features of the imperfections are estimated from electron beam profile measurements. Numerical simulations of halo removal rates are compared with experimental data taken at the Tevatron.

Morozov, I.A.; Stancari, G.; Valishev, A.; /Fermilab; Shatilov, D.N.; /Novosibirsk, IYF

2012-05-01

404

Flash X-Ray (FXR) Accelerator Optimization - Beam-induced Voltage Simulation and TDR Measurements  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL) is evaluating design alternatives to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell and pulse-power system. The goal is to create a more mono-energetic electron beam that will create an x-ray source with a smaller spot-size. Studying the interaction of the beam and accelerator cell will generate improved designs for high-current accelerators at Livermore and elsewhere. When an electron beam crosses the energized gap of an accelerator cell, the electron energy is increased. However, the beam with the associated electromagnetic wave also looses a small amount of energy because of the increased impedance seen across the gap. The phenomenon is sometimes called beam loading. It can also be described as a beam-induced voltage at the gap which is time varying. This creates beam energy variations that we need to understand and control. A high-fidelity computer simulation of the beam and cell interaction has been completed to quantify the time varying induced voltage at the gap. The cell and pulse-power system was characterized using a Time-domain Reflectometry (TDR) measurement technique with a coaxial air-line to drive the cell gap. The beam-induced cell voltage is computed by convoluting the cell impedance with measured beam current. The voltage was checked against other measurements to validate the accuracy. The simulation results predicted that there are significant beam-induced gap voltage variations. Beam-induced voltages from different current profiles and cell impedances were simulated and compared. This allows us to predict the effect on voltage regulation for different design alternatives before making hardware changes and high-voltage testing. The beam-induced voltages are incorporated into a larger accelerator system-model to quantify their effect on total beam energy variations.

Ong, M M; Vogtlin, G E

2004-04-07

405

The Fermilab accelerator control system  

SciTech Connect

For many years the Fermilab physics program has been dominated by the superconducting Tevatron accelerator producing beams for many fixed target and the proton-antiproton colliding beam experiments CDF and D0. More recently, major experiments have used beam from intermediate accelerators. The MiniBooNE and MINOS experiments use 8 and 120 GeV beam respectively for neutrino oscillation studies. Several other experiments and test beams have also used 120 GeV beam. This paper describes the control system for the accelerator complex that was originally developed for the start of Tevatron operation in 1983. This system is common to all accelerators in the chain, and has been successfully evolved to accommodate new hardware, new software platforms, new accelerators, and increasingly complex modes of operation.

Cahill, K.; Carmichael, L.; Finstrom, D.; Hendricks, B.; Lackey, Sharon L.; Neswold, R.; Nicklaus, D.; Patrick, J.; Petrov, A.; Schumann, C.; Smedinghoff, J.; /Fermilab

2008-01-01

406

Beam acceleration test in negative-ion based NBI system for JT-60U  

NASA Astrophysics Data System (ADS)

Beam extraction and acceleration test in the Negative Ion Based Neutral Beam Injector for JT-60U has been started using one ion source that is designed to produce a 500 keV, 22 A D- ion beam. Deuterium negative ions are produced in a cesium-seeded semi-cylindrical plasma generator and accelerated by a multi-aperture three-stage electrostatic accelerator. In the preliminary experiment of beam acceleration, the D- ion beam of 13.5 A was successfully accelerated to 400 keV for a pulse duration of 0.12 s. The negative ion beam power was 5.4 MW. The operating gas pressure in the plasma generator was as low as 0.22 Pa. The highest energy beam of 460 keV, 2.4 A, 0.44 s was also obtained. The ratio of extracted electron current to extracted negative ion current is estimated Ie/ID-<1. It was confirmed that the electron leak from the extractor to the accelerator is suppressed efficiently by the effects of biassing, electron trapping gap and magnetic field.

Watanabe, K.; Akino, N.; Araki, M.; Ebisawa, N.; Fujiwara, Y.; Hanada, M.; Honda, A.; Inoue, T.; Itoh, T.; Kawai, M.; Kazawa, M.; Koizumi, J.; Kuriyama, M.; Miyamoto, K.; Miyamoto, N.; Mogaki, K.; Nagase, A.; Ohara, Y.; Ohga, T.; Okumura, Y.; Oohara, H.; Ohshima, K.; Satoh, F.; Takahashi, S.; Takenouchi, T.; Usami, H.; Usui, K.; Yamamoto, M.; Yamazaki, T.

1996-07-01

407

Beam acceleration test in negative-ion based NBI system for JT-60U  

SciTech Connect

Beam extraction and acceleration test in the Negative Ion Based Neutral Beam Injector for JT-60U has been started using one ion source that is designed to produce a 500 keV, 22 A D{sup {minus}} ion beam. Deuterium negative ions are produced in a cesium-seeded semi-cylindrical plasma generator and accelerated by a multi-aperture three-stage electrostatic accelerator. In the preliminary experiment of beam acceleration, the D{sup {minus}} ion beam of 13.5 A was successfully accelerated to 400 keV for a pulse duration of 0.12 s. The negative ion beam power was 5.4 MW. The operating gas pressure in the plasma generator was as low as 0.22 Pa. The highest energy beam of 460 keV, 2.4 A, 0.44 s was also obtained. The ratio of extracted electron current to extracted negative ion current is estimated Ie/I{sub D{sup {minus}}}{lt}1. It was confirmed that the electron leak from the extractor to the accelerator is suppressed efficiently by the effects of biassing, electron trapping gap and magnetic field. {copyright} {ital 1996 American Institute of Physics.}

Watanabe, K.; Akino, N.; Araki, M.; Ebisawa, N.; Fujiwara, Y.; Hanada, M.; Honda, A.; Inoue, T.; Itoh, T.; Kawai, M.; Kazawa, M.; Koizumi, J.; Kuriyama, M.; Miyamoto, K.; Miyamoto, N.; Mogaki, K.; Nagase, A.; Ohara, Y.; Ohga, T.; Okumura, Y.; Oohara, H.; Ohshima, K.; Satoh, F.; Takahashi, S.; Takenouchi, T.; Usami, H.; Usui, K.; Yamamoto, M.; Yamazaki, T. [Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki-ken, 311-01 (Japan)

1996-07-01

408

Generation of annular, high-charge electron beams at the Argonne wakefield accelerator  

NASA Astrophysics Data System (ADS)

We present and discuss the results from the experimental generation of high-charge annular(ring-shaped)electron beams at the Argonne Wakefield Accelerator (AWA). These beams were produced by using laser masks to project annular laser profiles of various inner and outer diameters onto the photocathode of an RF gun. The ring beam is accelerated to 15 MeV, then it is imaged by means of solenoid lenses. Transverse profiles are compared for different solenoid settings. Discussion includes a comparison with Parmela simulations, some applications of high-charge ring beams,and an outline of a planned extension of this study.

Wisniewski, E. E.; Li, C.; Gai, W.; Power, J.

2013-01-01

409

Potential-Well Distortion, Microwave Instability, and Their Effects with Colliding Beams at KEKB  

SciTech Connect

Microwave instability in the Low Energy Ring of KEKB was studied using a broadband impedance model. The model gave excellent descriptions of longitudinal dynamics for both positive and negative momentum compactions. Moreover, it predicted that the threshold of microwave instability was a factor of two lower than the machine nominal operating bunch current. The prediction was confirmed by a measurement using the Belle detector. Furthermore, we integrated the longitudinal wakefield into the beam-beam simulation and applied it to study the combined effects in KEKB. As a result, the beam-beam simulation became truly three-dimensional with emittance growth in all three dimensions simultaneously as the beam currents increase. In addition, an observed mystery of asymmetry in the horizontal scan could also be explained by our simulations.

Cai, Yunhai; /SLAC; Flanagan, J.; Fukuma, H.; Funakoshi, Y.; Ieiri, T.; Ohmi, K.; Oide, K.; Suetsugu, Y.; /KEK, Tsukuba; Rorie, Jamal; /Hawaii U.

2009-04-01

410

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

411

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

412

Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic  

SciTech Connect

The design and current status of experiments to couple the Tapered Hybrid Undulator (THUNDER) to the Lawrence Berkeley National Laboratory (LBNL) laser plasma accelerator (LPA) to measure electron beam energy spread and emittance are presented.

Bakeman, M.S.; Van Tilborg, J.; Nakamura, K.; Gonsalves, A.; Osterhoff, J.; Sokollik, T.; Lin, C.; Robinson, K.E.; Schroeder, C.B.; Toth, Cs.; Weingartner, R.; Gruner, F.; Esarey, E.; Leemans, W.P.

2010-06-01

413

System for Producing Pulsed Ion BEAMS at the Pelletron Accelerator at Lund, Sweden. A Pilot Study.  

National Technical Information Service (NTIS)

An investigation of the possibilities to introduce a system for pulsed ion beams on the existing Pelletron accelerator. Simple calculations of requirements and performance have been made. (Atomindex citation 10:494826)

B. Paalson

1979-01-01

414

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

SciTech Connect

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

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

2004-07-08

415

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

PubMed Central

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

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

2013-01-01

416

High Energy Accelerator and Colliding Beam User Group. Progress report, May 1, 1980--March 31, 1981  

SciTech Connect

The major activities of the High Energy Physics Group at the University of Maryland during the current contract period have been: analysis of e{sup +}e{sup {minus}} events from the PLUTO detector at PETRA, design and construction of modifications to PLUTO for 2{gamma} physics, analyses of {nu}{sub {mu}}D{sub 2} bubble chamber pictures from Fermilab, completion of the {nu}{sub {mu}}e elastic scattering experiment at Fermilab, development and demonstration of an ultra cold neutron source produced by Doppler shifting, testing of equipment for the hadron jet experiment at Fermilab that is about to begin, and planning for large projects in the future.

Snow, G.A.

1980-12-01

417

Accelerating in the Future: Lasers Start to Produce Quality High Energy Electron Beams  

ScienceCinema

Twenty-five years ago, a new method was proposed for the acceleration of electrons to high energies using lasers. The simplest implementation of a so-called laser wakefield accelerator involves sending an intense laser pulse through a gas to ionize it and form a plasma of dissociated electrons and ions. The radiation pressure of the laser pushes the plasma electrons aside, creating a density modulation, or 'wake'. This changing electron density can result in fields that accelerate particles thousands of times more strongly than in conventional machines, accelerating electrons to high energies in short distances. The compactness of these accelerators would allow higher energies for the frontiers of fundamental physics and make clinical and laboratory applications of accelerators practical. In work that brings the promise of laser-driven particle accelerators dramatically closer to reality, we have produced high-quality electron beams in a plasma channel based accelerating structure akin to an optical fiber of only a few millimeters long.

418

Flyer Acceleration by Pulsed Ion Beam Ablation and Application for Space Propulsion  

NASA Astrophysics Data System (ADS)

Flyer acceleration by ablation plasma pressure produced by irradiation of intense pulsed ion beam has been studied. Acceleration process including expansion of ablation plasma was simulated based on fluid model. And interaction between incident pulsed ion beam and a flyer target was considered as accounting stopping power of it. In experiments, we used ETIGO-II intense pulsed ion beam generator with two kinds of diodes; 1) Magnetically Insulated Diode (MID, power densities of <100 J/cm2) and 2) Spherical-focused Plasma Focus Diode (SPFD, power densities of up to 4.3 kJ/cm2). Numerical results of accelerated flyer velocity agreed well with measured one over wide range of incident ion beam energy density. Flyer velocity of 5.6 km/s and ablation plasma pressure of 15 GPa was demonstrated by the present experiments. Acceleration of double-layer target consists of gold/aluminum was studied. For adequate layer thickness, such a flyer target could be much more accelerated than a single layer. Effect of waveform of ion beam was also examined. Parabolic waveform could accelerate more efficiently than rectangular waveform. Applicability of ablation propulsion was discussed. Specific impulse of 7000~8000 seconds and time averaged thrust of up to 5000~6000N can be expected. Their values can be controllable by changing power density of incident ion beam and pulse duration.

Harada, Nobuhiro; Buttapeng, Chainarong; Yazawa, Masaru; Kashine, Kenji; Jiang, Weihua; Yatsui, Kiyoshi

2004-02-01

419

Tevatron End-of-Run Beam Physics Experiments  

SciTech Connect

Before the Tevatron Collider Run II ended in September of 2011, a number of specialized beam study periods were dedicated to the experiments on various accelerator physics concepts and effects during the last year of the machine operation. The study topics included collimation with bent crystals and hollow electron beams, diffusion measurements and various aspects of beam-beam interactions. In this report we concentrate on the subject of beam-beam interactions, summarizing the results of beam experiments. The covered topics include offset collisions, coherent beam stability, effect of the bunch-length-to-beta-function ratio, and operation of AC dipole with colliding beams.

Valishev, A.; /Fermilab; Gu, X.; Miyamoto, R.; White, S.; /BNL; Schmidt, F.; /CERN; Qiang, J.; /LBNL

2012-05-01

420

NSAC Recommends a Relativistic Heavy-Ion Collider.  

ERIC Educational Resources Information Center

Describes the plan submitted by the Nuclear Science Advisory Committee to the Department of Energy and National Science Foundation urging construction of an ultrarelativistic heavy-ion collider designed to accelerate nucleon beams of ions as heavy as uranium. Discusses the process of selecting the type of facility as well as siting. (JM)

Physics Today, 1984

1984-01-01

421

The effect of beam loading on the characteristics of an electron linear accelerator  

Microsoft Academic Search

The secondary field created by the moving bunches of particles in retarding structures is determined and the main properties of those features of electron linear accelerators which are sensitive to beam loading effects are analysed. A detailed discussion is given of the operation of a linear accelerator in the stationary and transitional regimes and also when it is loaded by

E. L. Burshtein; G. V. Voskresenskii

1963-01-01

422

Accelerator Configuration for Polarized Proton-Antiproton Physics at FAIR  

SciTech Connect

The HESR at FAIR is being designed to accelerate and store unpolarized antiprotons in the momentum range from 1.5 to 15 Ge V/c. Different scenarios are proposed to accelerate polarized proton and antiproton beams and finally store and collide them. In this paper required modifications and extensions of the accelerator layout are discussed and luminosity estimates presented.

Lehrach, Andreas [Forschungszentrum Juelich, Institut fuer Kernphysik, Postfach 1913, D-52425 Juelich (Germany)

2007-06-13

423

Research and development of superconducting linear accelerators for neutral particle beam applications  

Microsoft Academic Search

Experiments with superconducting cavities designed for applications in continuous-wave, high-current ion linear accelerators have resulted in very high CW accelerating gradients, up to 18 MV\\/m, with only a few watts of power dissipation in the cavity walls. These results make the prospects for compact, lightweight Neutral Particle Beam accelerators very attractive, and they compel further work to develop RF superconductivity

J. R. Delayen; C. L. Bohn; W. L. Kennedy; G. L. Nicholls; C. T. Roche; L. Sagalovsky

1992-01-01

424

Electron beam deceleration measurements using the decelerator test beam line in the Compact Linear Collider test facility  

NASA Astrophysics Data System (ADS)

We discuss beam deceleration through a series of 12 power extraction and transfer structures, at the CLIC test facility 3 at CERN, as a proof-of-principle of the CLIC deceleration scheme. Up to 36% of the kinetic energy of an electron drive beam is extracted and converted to 12 GHz rf power. We look at the average and maximum energy loss of the particles, and compare them with simulations performed with the placet tracking code. The measured final energy is also compared to predictions based on the measured beam current and rf power in the structures. In the analysis we make use of the charge distribution form factor, taking into account the bunch length and the bunch phase. Finally, we look at the evolution of the transverse emittance with deceleration and compare the measured emittance with simulations.

Lillestøl, R. L.; Döbert, S.; Adli, E.; Olvegârd, M.

2014-03-01

425

Hadron-hadron colliders  

SciTech Connect

A comparison between electron-positron and proton-antiproton colliders is used to initiate a discussion of current trends in hadron-hadron colliders. Specific accelerators (SSC, FFAG, ISR, SPS, and TeV I) are discussed. Also, current detection technology is discussed. (AIP)

Tollestrup, A.V.

1985-11-20

426

Comparison of Discrete Klystron produced RF to two-beam produced RF for large accelerator systems  

NASA Astrophysics Data System (ADS)

We compare here some technical aspects, and with it the cost, of constructing a 500 GeV center of mass Linear Collider with either Discrete Klystron or with Two-Beam (relativistic Klystron) technology using X-band for the main linac. A comparison concept is applied to CLIC and NLC technologies, but not to a particular CLIC or NLC design. The methodology created can be extended to higher c.m.s. energies, if the reader so desires. .

Pitthan, Rainer

2001-05-01

427

Rf System Requirements for JLab’s MEIC Collider Ring  

SciTech Connect

The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. At the top energy are the electron and ion collider rings. For the ion ring, it accelerates five long ion bunches to colliding energy and rebunches ions into a train of very short bunches before colliding. A set of low frequency RF system is needed for the long ion bunch energy ramping. Another set of high frequency RF cavities is needed to rebunch ions. For the electron ring, superconducting RF (SRF) cavities are needed to compensate the synchrotron radiation energy loss. The impedance of the SRF cavities must be low enough to keep the high current electron beam stable. The preliminary design requirements of these RF cavities are presented.

Wang, Shaoheng [JLAB; Li, Rui [JLAB; Rimmer, Robert A. [JLAB; Wang, Haipeng [JLAB; Zhang, Yuhong [JLAB

2013-06-01

428

Beam instrumentation for future high intense hadron accelerators at Fermilab  

SciTech Connect

High intensity hadron beams of up to 2 MW beam power are a key element of new proposed experimental facilities at Fermilab. Project X, which includes a SCRF 8 GeV H{sup -} linac, will be the centerpiece of future HEP activities in the neutrino sector. After a short overview of this, and other proposed projects, we present the current status of the beam instrumentation activities at Fermilab with a few examples. With upgrades and improvements they can meet the requirements of the new beam facilities, however design and development of new instruments is needed, as shown by the prototype and conceptual examples in the last section.

Wendt, M.; Hu, M.; Tassotto, G.; Thurman-Keup, R.; Scarpine, V.; Shin, S.; Zagel, J.; /Fermilab

2008-08-01

429

Issues in Acceleration of A Muon Beam for a Neutrino Factory.  

National Technical Information Service (NTIS)

We have developed a concept for acceleration of a large phase-space, pulsed muon beam from 190 MeV to 50 GeV as part of a collaborative study of the feasibility of a neutrino factory based on in-flight decay of muons. The muon beam's initial energy spread...

J. Delayen D. Douglas L. Harwood V. Lebedev C. Leemann

2001-01-01

430

The physics of production, acceleration and neutralization of large negative ion beams  

Microsoft Academic Search

Neutral beam systems for the next generation of magnetic fusion devices will be based on negative ions. Developments are progressing steadily, and large negative ion-based systems are under preparation for JT60-U and LHD, and are being considered for ITER. An overview of the physics of the production, acceleration and neutralization of large negative ion beams is given. The present state

J. Pamela

1995-01-01

431

Narrowband beam loading compensation in the Fermilab Main Injector accelerating cavities  

Microsoft Academic Search

A narrowband beam loading compensation system was installed for the Main Injector accelerating cavities. This feedback operates solely on the fundamental resonant mode of the cavity. This paper describes modifications to the high level radiofrequency system required to make the system operational. These modifications decreased the effect of steady-state beam loading by a factor of 10 and improved the reliability

Joseph E. Dey; J. Steimel; J. Reid

2001-01-01

432

A multiwire proportional chamber system for monitoring low momentum beam in accelerators  

Microsoft Academic Search

A diagnostic is being developed at the Los Alamos Neutron Science Center (LANSCE) for the purpose of identifying low momentum beam tails in the linear accelerator. These tails must be eliminated in order to maintain the transverse and longitudinal beam size. Instead of the currently used phosphor camera system, this instrument consists of a multiwire proportional chamber (MWPC) front end

Rob Merl; Floyd Gallegos; Chandra Pillai; Fred Shelley; Benjamin J. Sanchez; Andy Steck

2003-01-01

433

[Stereotactic radiotherapy with linear accelerators. Dosage considerations on collimators and photon beam energy].  

PubMed

The small X-ray beam profiles produced by linear accelerators and used in stereotactic radiosurgery were studied. Circular focusing and not-focusing beams outlined by additional collimators (diameter ranging 10 to 30 mm) and square field outlined by the jaws (field size 10 to 30 mm) were measured. 6 and 18-MV X-ray beams from a dual energy accelerator and 6 and 15-MV X-ray beams produced by 2 single-energy accelerators were used. Measurements were carried out with Kodak X Omat V films in a perspex phantom in the same conditions for all the fields. To study the profile characteristics we introduced the V80/V20 = (R80/R20)3 ratio where R80 and R20 are respectively the mean distance of the 80% and 20% isodose lines from the beams axis. Measurement results show that 6-MV X-ray beams have a higher V80/V20 ratio than the ones obtained with the other energies. There is no significant difference between the beams produced with focused collimators and those produced with not-focused collimators. Square fields outlined by the jaws have a V80/V20 ratio greatly dependent on the accelerator used. This ratio is generally worse than the ones obtained with beams outlined by additional collimators. PMID:7617913

Somigliana, A B; Filice, S; Stucchi, C; Gramaglia, A; Villa, S; Pasqualotto, C; Brusa, A; Crippa, M; Casolino, D; Scorsetti, M

1995-05-01

434

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

Microsoft Academic Search

In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a ‘scaling’ principle has been applied to avoid beam blow-up and

R. Barlow; J. S. Berg; N. Bliss; R. K. Buckley; J. A. Clarke; M. K. Craddock; R. D’Arcy; R. Edgecock; J. M. Garland; Y. Giboudot; P. Goudket; S. Griffiths; C. Hill; S. F. Hill; K. M. Hock; D. J. Holder; M. G. Ibison; F. Jackson; S. P. Jamison; C. Johnstone; J. K. Jones; L. B. Jones; A. Kalinin; E. Keil; D. J. Kelliher; I. W. Kirkman; S. Koscielniak; K. Marinov; N. Marks; B. Martlew; P. A. McIntosh; J. W. McKenzie; F. Méot; K. J. Middleman; A. Moss; B. D. Muratori; J. Orrett; H. L. Owen; J. Pasternak; K. J. Peach; M. W. Poole; Y. N. Rao; Y. Saveliev; D. J. Scott; S. L. Sheehy; B. J. A. Shepherd; R. Smith; S. L. Smith; D. Trbojevic; S. Tzenov; T. Weston; A. Wheelhouse; P. H. Williams; A. Wolski; T. Yokoi; S. Machida

2012-01-01

435

High-Energy Laser-Accelerated Electron Beams for Long-Range Interrogation  

SciTech Connect

We are studying the use of 0.1 1.0 GeV laser-accelerated electron beams as active interrogation probes for long-standoff radiography or nuclear activation of concealed special nuclear material. Use of beams in this energy range is largely unexplored, but such beams could provide notable advantages over lower-energy beams and x-rays. High-energy laser-accelerated electrons exhibit large penetration range through air and solids, and low beam divergence for both direct beams and secondary Bremsstrahlung x-rays. We present laboratory measurements of radiography and activation, using the high-power Diodes laser system at the University of Nebraska, as well as MCNP and GEANT Monte Carlo simulation results used to aid experiment design and interpretation.

Cummingham, N. J. [University of Nebraska, Lincoln; Banerjee, Sudeep [University of Nebraska, Lincoln; Ramanathan, Vidya [University of Nebraska, Lincoln; Powell, Nathan [University of Nebraska, Lincoln; Chandler-Smith, Nate [University of Nebraska, Lincoln; Vane, C Randy [ORNL; Schultz, David Robert [ORNL; Pozzi, Sara [University of Michigan; Clarke, Shaun [University of Michigan; Beene, James R [ORNL; Umstadter, Donald [University of Nebraska, Lincoln

2009-01-01

436

Beam Based HOM Analysis of Accelerating Structures at the TESLA Test Facility Linac  

SciTech Connect

The beam emittance in future linear accelerators for high energy physics and SASE-FEL applications depends highly on the field performance in the accelerating structures, i.e. the damping of higher order modes (HOM). Besides theoretical and laboratory analysis, a beam based analysis technique was established [1] at the TESLA Test Facility (TTF) linac. It uses a charge modulated beam of variable modulation frequency to excite dipole modes. This causes a modulation of the transverse beam displacement, which is observed at a downstream BPM and associated with a direct analysis of the modes at the HOM-couplers. A brief introduction of eigenmodes of a resonator and the concept of the wake potential is given. Emphasis is put on beam instrumentation and signal analysis aspects, required for this beam based HOM measurement technique.

Wendt, M.; Schreiber, S.; Castro, P.; Gossel, A.; /DESY; Huning, M.; /Fermilab; Devanz, G.; Jablonka, M.; Magne, C.; Napoly, O.; /Saclay; Baboi, N.; /SLAC

2005-08-09

437

On the Pointing Angle of Electron Beams from Laser Wakefield Accelerators  

SciTech Connect

Laser wakefield accelerators offer electron beams which could be useful for many applications. However, the problem of stabilizing the electron beam parameters has not been resolved yet. Here, we propose a method to minimize the electron beam pointing and report the generation of a relativistic electron beam with a stabilized pointing angle of 2 mrad (rms). This was achieved by using asymmetric non-relativistic laser pulses interacting with low-density helium gas jet. In such a weakly-nonlinear regime, symmetric laser pulses were neither able to generate reproducible nor stable electron beams. Thus, we propose asymmetric laser pulses for generating electron beams having stable and small pointing angles from laser-plasma accelerators.

Hafz, N.; Lee, S. K.; Yu, T. J.; Lee, J.; Sung, J. H. [Advanced Photonics Research Institute, GIST, Gwangju 500-712 (Korea, Republic of)

2010-11-04

438

Pulsed power for particle beam accelerators in military applications  

SciTech Connect

Techniques useful for generating and conditioning power for high energy pulsed accelerators with potential weapon applications are described. Pulsed electron accelerators are exemplified by ETA and ATA at Lawrence Livermore Laboratories and RADLAC at Sandia Laboratories Albuquerque. Pulse-power techniques used in other applications are briefly mentioned, including some that may be useful for collective ion accelerators. The limitations of pulse-power and the general directions of desirable development are illustrated. The main needs are to increase repetition rate and to decrease size.

Smith, I.D.

1980-06-20