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1

Beam-beam interaction in P-P colliding accelerators  

SciTech Connect

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

Parzen, G.

1982-08-01

2

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

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

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

SciTech Connect

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

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

2010-02-17

6

Evaluation of the colliding beam accelerator first string full cell vacuum system  

Microsoft Academic Search

The CBA (colliding beam accelerator, formerly know as ISABELLE) full cell magnet system consisting of six superconducting dipole magnets and two superconducting quadrupole magnets requires two separate vacuum systems. One, known as beam vacuum, operates below 3 x 10⁻¹¹ Torr and the other, known as insulating vacuum, operates at less than 10⁻⁷ Torr to isolate cryocircuits from atmosphere and from

C. L. Foerster; J. Briggs; C. Christianson; P. Stattel

1984-01-01

7

Effects of rf breakdown on the beam in the Compact Linear Collider prototype accelerator structure  

NASA Astrophysics Data System (ADS)

Understanding the effects of rf breakdown in high-gradient accelerator structures on the accelerated beam is an extremely relevant aspect in the development of the Compact Linear Collider (CLIC) and is one of the main issues addressed at the Two-beam Test Stand at the CLIC Test Facility 3 at CERN. During a rf breakdown high currents are generated causing parasitic magnetic fields that interact with the accelerated beam affecting its orbit. The beam energy is also affected because the power is partly reflected and partly absorbed thus reducing the available energy to accelerate the beam. We discuss here measurements of such effects observed on an electron beam accelerated in a CLIC prototype structure. Measurements of the trajectory of bunch trains on a nanosecond time scale showed fast changes in correspondence of breakdown that we compare with measurements of the relative beam spots on a scintillating screen. We identify different breakdown scenarios for which we offer an explanation based also on measurements of the power at the input and output ports of the accelerator structure. Finally we present the distribution of the magnitude of the observed changes in the beam position and we discuss its correlation with rf power and breakdown location in the accelerator structure.

Palaia, A.; Jacewicz, M.; Ruber, R.; Ziemann, V.; Farabolini, W.

2013-08-01

8

Simulation of quasimonoenergetic electron beams produced by colliding pulse wakefield acceleration  

SciTech Connect

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

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

2008-11-15

9

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

10

Relativistic-klystron two-beam accelerator as a power source for future linear colliders  

SciTech Connect

The technical challenge for making two-beam accelerators into realizable power sources for high-energy colliders lies in the creation of the drive beam and in its propagation over long distances through multiple extraction sections. This year we have been constructing a 1.2&A, l-MeV, induction gun for a prototype relativistic klystron two-beam accelerator (RK-TBA). The electron source will be a 8.9 cm diameter, thermionic, flat-surface cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1% energy variation), and a normalized edge emittance of less than 300 pi-mm-n-n. The prototype accelerator will be used to study physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. We have also been studying optimization parameters, such as frequency, for the application of the RK-TBA concept to multi-TeV linear colliders. As an rf power source the RK-TBA scales favorably up to frequencies around 35 GHz. An overview of this work with details of the design and performance of the prototype injector, beam line, and diagnostics will be presented.

Anderson, D E; Eylon, S; Henestroza, E; Houck, T L; Lidia, M; Vanecek, D L; Westenskow, G A; Yu, S S

1998-10-05

11

Relativistic-Klystron two-beam accelerator as a power source for future linear colliders  

SciTech Connect

The technical challenge for making two-beam accelerators into realizable power sources for high-energy colliders lies in the creation of the drive beam and in its propagation over long distances through multiple extraction sections. This year we have been constructing a 1.2-kA, 1-MeV, induction gun for a prototype relativistic klystron two-beam accelerator (RK-TBA). The electron source will be a 8.9 cm diameter, thermionic, flat-surface cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1% energy variation), and a normalized edge emittance of less than 300 pi-mm-mr. The prototype accelerator will be used to study, physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. We have also been studying optimization parameters, such as frequency, for the application of the RK-TBA concept to multi-TeV linear colliders. As an rf power source the RK-TBA scales favorably up to frequencies around 35 GHz. An overview of this work with details of the design and performance of the prototype injector, beam line, and diagnostics will be presented.

Lidia, S. M.; Anderson, D. E.; Eylon, S.; Henestroza, E.; Vanecek, D. L.; Yu, S. S. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Houck, T. L.; Westenskow, G. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

1999-05-07

12

The generation and acceleration of low emittance flat beams for future linear colliders  

SciTech Connect

Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of {gamma}{epsilon}{sub x} = 3{times}10{sup {minus}6} m-rad and {gamma}{epsilon}{sub y} = 3{times}10{sup {minus}8} m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate fundamental'' limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future.

Raubenheimer, T.O.

1991-11-01

13

The generation and acceleration of low emittance flat beams for future linear colliders  

SciTech Connect

Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of {gamma}{epsilon}{sub x} = 3{times}10{sup {minus}6} m-rad and {gamma}{epsilon}{sub y} = 3{times}10{sup {minus}8} m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate ``fundamental`` limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future.

Raubenheimer, T.O.

1991-11-01

14

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

15

Evaluation of the colliding beam accelerator first string full cell vacuum system  

SciTech Connect

The CBA (colliding beam accelerator, formerly know as ISABELLE) full cell magnet system consisting of six superconducting dipole magnets and two superconducting quadrupole magnets requires two separate vacuum systems. One, known as beam vacuum, operates below 3 x 10/sup -11/ Torr and the other, known as insulating vacuum, operates at less than 10/sup -7/ Torr to isolate cryocircuits from atmosphere and from the UHV beam tubes. The UHV bore tube is isolated from the 4.0 K magnet by 36 layers of superinsulation and insulating vacuum. Heat load measurements on the bore tube have been completed and found to agree with data obtained in smaller controlled experiments. Measurements of helium, accumulated on cryogenic pumped charcoal panels over many weeks, have verified sensitive helium mass spectrometer leak detection methods for vacuum integrity, proving sound design of the welded complex. The full cell was assembled and operated under conditions that would exist in the completed machine. Pressures below 2 x 10/sup -11/ Torr beam vacuum requirement and below 1 x 10/sup -7/ Torr insulating vacuum, were routinely achieved during all phases of the full cell operation and support systems testing.

Foerster, C.L.; Briggs, J.; Christianson, C.; Stattel, P.

1984-04-01

16

Design study of beam dynamics issues for a one 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. We present, in this paper, the beam dynamics part of this study. We have achieved in our design study acceptable transverse and longitudinal beam stability properties for the resulting high efficiency and low cost RK-TBA. {copyright} 1995 {ital American Institute of Physics}.

Li, H. [Lawrence Berkeley Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States); Houck, T. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); Goffeney, N.; Henestroza, E.; Sessler, A. [Lawrence Berkeley Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States); Westenskow, G. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); Yu, S. [Lawrence Berkeley Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States)

1995-06-01

17

Next linear collider test accelerator injector upgrade  

Microsoft Academic Search

The Next Linear Collider Test Accelerator (NLCTA) being built at SLAC will integrate the new technologies of X-band accelerator structures and RF systems for the next linear collider, demonstrate multibranch beam-loading energy compensation and suppression of higher-order deflecting modes, and measure the dark current generated by RF field emission in the accelerator [NLC Test Accelerator Conceptual Design Report, SLAC Report

A. D. Yeremian; R. H. Miller

1996-01-01

18

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

19

Beam Collimation at Hadron Colliders  

NASA Astrophysics Data System (ADS)

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.

Mokhov, N. V.

2003-12-01

20

Next Linear Collider test accelerator injector upgrade  

Microsoft Academic Search

The Next Linear Collider Test Accelerator (NLCTA) being built at SLAC will integrate the new technologies of X-band Accelerator structures and RF systems for the Next Linear Collider, demonstrate multibunch beam-loading energy compensation and suppression of higher-order deflecting modes, and measure the dark current generated by RF field emission in the accelerator. The current injector being constructed for phase 1

A. D. Yeremian; R. H. Miller

1995-01-01

21

Accelerator physics at the Superconducting Super Collider  

Microsoft Academic Search

This book is a collection of lectures given at the Superconducting Super Collider Laboratory over a span of one year (from October 1, 1992 to September 30, 1993). These lectures are on varied topics covering beam dynamics, beam emittance, collective effects and beam diagnostics. These topics deal with various aspects of accelerator physics. There were twenty-six lectures presented and twenty-one

Y. T. Yan; J. P. Naples; M. J. Syphers

1995-01-01

22

Linear Colliders: Achieving High Beam Power  

NASA Astrophysics Data System (ADS)

For the next generation linear colliders, the luminosity will be approximately proportional to the average power of the colliding beams. Thus it is the goal of the accelerator systems of these machines to transfer wall plug power, which will be limited to a few hundred megawatts to be practical, to beam power in an efficient and low cost manner. Just as important, the beam acceleration must not degrade the small beam emittances that are necessary for high luminosity. In this paper, we examine the linac designs of the leading linear collider proposals (CLIC, JLC, NLC and TESLA) in these respects and review their R&D status.

Adolphsen, Chris

2002-04-01

23

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

24

Relativistic-klystron two-beam-accelerator as a power source for a 1 TeV next linear collider: A systems study  

SciTech Connect

A physics, engineering, and costing study has been conducted to explore the feasibility of a relativistic-klystron two-beam-accelerator system as a power source candidate for a 1 TeV linear collider. We present a point design example which has acceptable transverse and longitudinal beam stability properties. Preliminary ``bottom-up`` cost estimate yields the full power source system at less than 1 billion dollars. The overall efficiency for rf production is estimated to be 36%.

Yu, S.; Goffeney, N. [Lawrence Berkeley Lab., CA (United States); Deadrick, F. [Lawrence Livermore National Lab., CA (United States)] [and others

1994-10-01

25

Beam instabilities in Very Large Hadron Collider  

Microsoft Academic Search

The Very Large Hadron Collider (VLHC) is a superconducting proton-proton collider with approximately 100 TeV cm and approximately 1034 s-1 cm-2 luminosity. 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

V. Shiltsev; J. Marriner; V. Danilov

1999-01-01

26

LEPTON ACCELERATORS AND COLLIDERS: Observation of beam instability in the SSRF storage ring  

NASA Astrophysics Data System (ADS)

During the SSRF(Shanghai Synchrotron Radiation Facility) storage ring phase-I commissioning, some instabilities have been observed, and the broadband impedance has also been measured. The primary instabilities at present stage are vertical beam blow up and resistive wall instability.

Jiang, Bo-Cheng; Chen, Guang-Ling; Chen, Jian-Hui; Liu, Gui-Min; Zhao, Zhen-Tang

2009-06-01

27

Next linear collider test accelerator injector design and status  

SciTech Connect

The Next Linear Collider Test Accelerator (NLCTA) being built at SLAC will integrate the new technologies of X-band accelerator structures and RF systems for the Next Linear Collider, demonstrate multibunch beam-loading energy compensation and suppression of higher-order deflecting modes, measure transverse components of the accelerating field, and measure the dark current generated by RF field emission in the accelerator Injector design and simulation results for the NLCTA injector are discussed.

Yeremian, A.D.; Miller, R.H.; Wang, J.W.

1994-08-01

28

Next linear collider test accelerator injector upgrade  

SciTech Connect

The Next Linear Collider Test Accelerator (NLCTA) being built at SLAC will integrate the new technologies of X-band Accelerator structures and RF systems for the Next Linear Collider, demonstrate multibunch beam-loading energy compensation and suppression of higher-order deflecting modes, and measure the dark current generated by RF field emission in the accelerator. The current injector being constructed for phase 1 of the NLCTA tests is a simple injector consisting of a gun with a 150 ns long pulse and X-band bunching and accelerating system. While the injector will provide average currents comparable to what is needed for NLC it will not provide the bunch structure since every X-band RF bucket will be filled. The injector upgrade will produce a similar bunch train as planned for NLC mainly a train of bunches 1.4 ns apart with 3 nC in each bunch up to 50 to 60 MeV. The bunching system for the upgrade is more elaborate than the current injector and the plan is to produce a bunch train right at the gun. The difference between the NLCTA injector upgrade and the planned injector for NLC is that the NLCTA injector will not have polarized beam and the accelerator sections are X-band rather than S-band. If the authors are able to produce beams comparable to the NLC requirements with the X-band injector then it should be easier to do with the S-band.

Yeremian, A.D.; Miller, R.H.

1995-08-01

29

Critical beam intensity issues in hadron colliders  

SciTech Connect

I would like to discuss how some of the issues that have been talked about at this workshop (and some that haven`t) are reflected in the performance of hadron colliders. Hadron colliders, be they proton-antiproton, proton-proton, or heavy ion, are typically supported by a half-dozen other accelerators each of which has its own set of performance characteristics and limitations. As a result, when designing, building, operating, or upgrading a hadron collider choices must be made that determine not only overall performance but also the ultimate configuration of the complex. It is impossible to discuss here the full range of issues that one has to consider in projecting performance in a hadron collider. I will concentrate on a few and attempt to make some observations on how/when various effects relating to beam intensity are important. We will start with a short introduction that is intended to give the ``lay of the land`` in hadron colliders--what are the performance issues and what are the fundamental mechanisms that limit performance? We will then examine how choices in beam parameters can and have influenced performance, and how strategies are likely to change as we contemplate higher energy colliders. Finally, I will offer some opinions on what research directions are dictated for improving the luminosity delivered from hadron colliders.

Holmes, S.D.

1995-11-01

30

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

SciTech Connect

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

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

1995-02-22

31

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

32

Two-beam accelerator  

SciTech Connect

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

Selph, F.B.

1984-09-01

33

Coherent bremsstrahlung at colliding beams  

NASA Astrophysics Data System (ADS)

A new type of radiation at colliders with short bunches - coherent bremsstrahlung (CBS) - was recently considered. In the present paper, we considered the main characteristics of CBS for the known projects of the e+e--colliders PEP-II, KEK-B, VEPP-4 and DA/?NE. At this collider it will be emitted dN?~(107- 108)dE?/E? photons for a single collision in the energy range E?<~10 KeV. It seems that CBS can be a potential tool for optimizing collisions and for measuring beam parameters. Indeed, the bunch length ?z can be found from the CBS spectrum because critical energy Ec~1/?z the horizontal transverse bunch size ?x is related to dN?~1/?x2. Besides, CBS may be very useful for a fast control over an impact parameter R between the colliding bunch axes because a dependence of dN? on /R has a very specific behavior.

Polityko, S. I.

2001-01-01

34

Accelerator R&D toward Muon Collider and Neutrino Factory  

SciTech Connect

Over the last decade there has been significant progress in developing the concepts and technologies needed to produce, capture, accelerate and collide high intensity beams of muons. At present, a high-luminosity multi-TeV muon collider presents a viable option for the next generation lepton-lepton collider, which is believed to be needed to fully explore high energy physics in the era following LHC discoveries. Such a collider can offer superb energy resolution, smaller size, and potentially cost and power consumption compared to multi-TeV e{sup +}e{sup -} linear colliders. This article briefly reviews the motivation, design and status of accelerator R&D for Muon Collider and Neutrino Factory.

Shiltsev, Vladimir; /Fermilab

2009-10-01

35

Accelerator R&D toward Muon Collider and Neutrino Factory  

NASA Astrophysics Data System (ADS)

Over the last decade there has been significant progress in developing the concepts and technologies needed to produce, capture, accelerate and collide high intensity beams of muons. At present, a high-luminosity multi-TeV muon collider presents a viable option for the next generation lepton-lepton collider, which is believed to be needed to fully explore high energy physics in the era following LHC discoveries. Such a collider can offer superb energy resolution, smaller size, and potentially cost and power consumption compared to multi-TeV e + e - linear colliders. This article briefly reviews the motivation, design and status of accelerator R&D for Muon Collider and Neutrino Factory.

Shiltsev, V.

2010-12-01

36

A systems study of an RF power source for a 1 TeV next linear collider based upon the relativistic-klystron two-beam accelerator  

SciTech Connect

A systems study, including physics, engineering and costing, has been conducted to assess the feasibility of a relativistic-klystron two-beam-accelerator (RK-TBA) system as a RF power source candidate for a 1 TeV linear collider. Several key issues associated with a realizable RK-TBA system have been addressed, and corresponding schemes have been developed and examined quantitatively. A point design example has been constructed to present a concrete conceptual design which has acceptable transverse and longitudinal beam stability properties. The overall efficiency of RF production for such a power source is estimated to be 36%, and the cost of the full system is estimated to be less than 1 billion dollars.

Yu, S.; Goffeney, N. [Lawrence Berkeley Lab., CA (United States); Deadrick, F. [Lawrence Livermore National Lab., CA (United States)] [and others

1994-11-01

37

A systems study of an RF power source for a 1 TeV next linear collider based upon the relativistic-klystron two-beam accelerator  

SciTech Connect

A systems study, including physics, engineering, and costing, has been conducted to assess the feasibility of a relativistic-klystron two-beam-accelerator (RK-TBA) system as a RF power source candidate for a 1 TeV linear collider. Several key issues associated with a realizable RK-TBA system have been addressed, and corresponding schemes have been developed and examined quantitatively. A point design example has been constructed to present a concrete conceptual design which has acceptable transverse and longitudinal beam stability properties. The overall efficiency of RF production for such a power source is estimated to be 36%, and the cost of the full system is estimated to be less than 1 billion dollars. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Yu, S. [Lawrence Berkeley Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States); Deadrick, F. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); Goffeney, N.; Henestroza, E. [Lawrence Berkeley Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States); Houck, T. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); Li, H.; Peters, C.; Reginato, L.; Sessler, A.; Vanecek, D. [Lawrence Berkeley Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States); Westenskow, G. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1995-07-05

38

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

39

Beam stability issues in very large hadron collider  

Microsoft Academic Search

The Very Large Hadron Collider (VLHC) is a superconducting proton–proton collider with approximately 100 TeV c.m. energy and approximately 1034s?1cm?2 luminosity [G. Dugan, in: Proceedings of the 1999 IEEE Particle Acceleration Conference, New York, 1999, p. 48.]11VLHC Web page http:\\/\\/vlhc.org. Currently, beam dynamics in this future accelerator is the subject of intensive studies within the framework of the US-wide VLHC

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

2000-01-01

40

High Frequency Planar Accelerating Structures for Future Linear Colliders  

SciTech Connect

Modern microfabrication techniques based on deep etch x-ray lithography (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 ({ge} 5TeV) must operate at high frequency ({ge} 30GHz). This implies the need of a large number of intricate accelerating structures with ever smaller dimensions and extremely tight manufacturing tolerances, imposing new challenges in mass-production, precision fabrication techniques. Microfabrication is particularly suitable for meeting this need. Secondly, luminosity requirements suggest the use of multi-bunch acceleration of electrons and positrons in the linear collider. In order for these schemes to accelerate low-emittance beams over a long distance, it is important that the wakefield effects be reduced to a minimum in the accelerating structure. Asymmetric planar structures have more geometric degrees of freedom than cylindrically symmetric structures. In addition to detuning, these can be utilized to further reduce the wakefields. 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.

Yu, D.

2005-01-26

41

ACCELERATION FOR A HIGH ENERGY MUON COLLIDER  

SciTech Connect

The authors describe a method for designing the acceleration systems for a muon collider, with particular application and examples for a high energy muon collider. This paper primarily concentrates on design considerations coming from longitudinal motion, but some transverse issues are briefly discussed.

BERG,J.S

2000-04-07

42

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

43

Advanced acceleration schemes for e+e - colliders  

NASA Astrophysics Data System (ADS)

The physics case for a TeV-scale electron-positron linear collider has been endorsed by the international high energy physics community. In support of this physics program, the International Linear Collider Global Design Effort (ILC-GDE) has developed a detailed design for a 500 GeV collider based on 1.3 GHz superconducting rf cavities that would operate at 35 MV/m. At the same time, the international accelerator R&D program has been pursuing a number of alternate technologies that may achieve higher acceleration gradients and may offer access to an increased energy range. These technologies include rf-driven and beam-driven high gradient normal conducting accelerator systems, laser-driven and beam-driven dielectric accelerators and laser-driven and beam-driven plasma accelerators. These alternate technologies have the potential for much higher acceleration gradients than the ILC design with gradients ranging from 100 to 30,000 MV/m and would potentially be less costly per GeV. This talk will discuss the present status of these alternate technologies, describe their potential advantages and risks, and consider the development timelines. The talk will also cover some of the near-term applications of these technologies including accelerators for Free Electron Lasers or compact linacs for medicine or industry.

Raubenheimer, Tor

2011-04-01

44

Colliding Laser Pulses for Laser-Plasma Accelerator Injection Control  

SciTech Connect

Decoupling injection from acceleration is a key challenge to achieve compact, reliable, tunable laser-plasma accelerators (LPA). In colliding pulse injection the beat between multiple laser pulses can be used to control energy, energy spread, and emittance of the electron beam by injecting electrons in momentum and phase into the accelerating phase of the wake trailing the driver laser pulse. At LBNL, using automated control of spatiotemporal overlap of laser pulses, two-pulse experiments showed stable operation and reproducibility over hours of operation. Arrival time of the colliding beam was scanned, and the measured timing window and density of optimal operation agree with simulations. The accelerator length was mapped by scanning the collision point.

Plateau, G. R. [LOASIS Program at LBNL, Berkeley, CA 94720 (United States); Ecole Polytechnique, Palaiseau, 91128 (France); Geddes, C. G. R.; Matlis, N. H.; Mittelberger, D. E.; Nakamura, K.; Schroeder, C. B.; Esarey, E.; Leemans, W. P. [LOASIS Program at LBNL, Berkeley, CA 94720 (United States); Cormier-Michel, E. [Tech-X Corporation, Boulder, CO 80303 (United States)

2010-11-04

45

Colliding Laser Pulses for Laser-Plasma Accelerator Injection Control  

SciTech Connect

Decoupling injection from acceleration is a key challenge to achieve compact, reliable, tunable laser-plasma accelerators (LPA). In colliding pulse injection the beat between multiple laser pulses can be used to control energy, energy spread, and emittance of the electron beam by injecting electrons in momentum and phase into the accelerating phase of the wake trailing the driver laser pulse. At LBNL, using automated control of spatiotemporal overlap of laser pulses, two-pulse experiments showed stable operation and reproducibility over hours of operation. Arrival time of the colliding beam was scanned, and the measured timing window and density of optimal operation agree with simulations. The accelerator length was mapped by scanning the collision point.

Plateau, Guillaume; Geddes, Cameron; Matlis, Nicholas; Cormier-Michel, Estelle; Mittelberger, Daniel; Nakamura, Kei; Schroeder, Carl; Esarey, Eric; Leemans, Wim

2011-07-19

46

Highly polarized electron beams for linear colliders.  

National Technical Information Service (NTIS)

The SLC operates with electron beams having a polarization of (approximately) 80%. The physics opportunities for future colliders will be greatly enhanced if the beam polarization can be significantly higher. The prospects for achieving electron single-be...

J. E. Clendenin

1998-01-01

47

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

48

Development of a CVD diamond Beam Condition Monitor for CMS at the Large Hadron Collider  

Microsoft Academic Search

The CERN Large Hadron Collider (LHC) will store 2808 bunches per colliding beam, with each bunch consisting of 1011 protons at an energy of 7TeV. If there is a failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen

L. Fernandez-Hernando; D. Chong; R. Gray; C. Ilgner; A. MacPherson; A. Oh; T. Pritchard; R. Stone; S. Worm

2005-01-01

49

Beam dynamics issues for linear colliders  

SciTech Connect

In this paper we discuss various beam dynamics issues for linear colliders. The emphasis is to explore beam dynamics effects which lead to an effective dilution of the emittance of the beam and thus to a loss of luminosity. These considerations lead to various tolerances which are evaluated for a particular parameter set.

Ruth, R.D.

1987-09-01

50

Relativistic klystron two-beam accelerator  

SciTech Connect

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

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

1994-10-01

51

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

52

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

53

Collider and detector protection at beam accidents  

SciTech Connect

Dealing with beam loss due to abort kicker prefire is considered for hadron colliders. The prefires occurred at Tevatron (Fermilab) during Run I and Run II are analyzed and a protection system implemented is described. The effect of accidental beam loss in the Large Hadron Collider (LHC) at CERN on machine and detector components is studied via realistic Monte Carlo calculations. The simulations show that beam loss at an unsynchronized beam abort would result in severe heating of conventional and superconducting magnets and possible damage to the collider detector elements. A proposed set of collimators would reduce energy deposition effects to acceptable levels. Special attention is paid to reducing peak temperature rise within the septum magnet and minimizing quench region length downstream of the LHC beam abort straight section.

I. L. Rakhno; N. V. Mokhov; A. I. Drozhdin

2003-12-10

54

TRANSVERSE BEAM TRANSFER FUNCTIONS OF COLLIDING BEAMS IN RHIC  

SciTech Connect

We use transverse beam transfer functions to measure tune distributions of colliding beams in RHIC. The tune has a distribution due to the beam-beam interaction, nonlinear magnetic fields -- particularly in the interaction region magnets, and non-zero chromaticity in conjunction with momentum spread. The measured tune distributions are compared with calculations.

FISCHER,W.; BLASKIEWICZ, M.; CALAGA, R.; CAMERON, P.; HERR, W.; PIELONI, T.

2007-06-25

55

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

Microsoft Academic Search

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

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

2007-01-01

56

Fermilab collider run 1b accelerator performance  

SciTech Connect

This report summarizes the performance of Run 1b as of the end of July 1995. This run is the conclusion of Fermilab Collider Run 1, which consists of Run 1a (May 1992 - May 1993) and Run 1b (January 1994 - February 1996). Run 1b is characterized by being the first with the new 400 MeV Linac. At this time the run is not complete. Colliding beam physics is scheduled to resume after the summer 1995 shut down and continue until mid-February 1996. All of the operation to date is at a Tevatron energy of 900 GeV. This report emphasizes performance numbers and the various improvements made to systems to achieve this performance. It will only discuss the underlying physics to a limited extent. The report is divided into sections on: run statistics, I&C issues, proton source performance, antiproton source performance, main ring performance, Tevatron performance, and a summary.

Bharadwaj, V.; Halling, M.; Lucas, P.; McCrory, E.; Mishra, S.; Pruss, S.; Werkema, S.

1996-04-01

57

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

58

Channeling acceleration: A path to ultrahigh energy colliders  

SciTech Connect

Acceleration of charged particles along crystal channels has been proposed earlier in an attempt to achieve high acceleration gradient while at the same time to suppress excessive emittance growth. Recently the authors demonstrated that a particle in a generic focusing channel can in principle absolutely damp to its transverse ground state without any quantum excitation. This yields the minimum beam emittance that one can ever attain, {gamma}{epsilon}{sub min} = {h_bar}/2mc, limited only by the uncertainty principle. In this paper they discuss sources of excitation when a more realistic channel is considered, including bremsstrahlung and multiple Coulomb scattering. They investigate the possibility of colliding ultrahigh energy particles in such strong focusing channels without the need of a final focusing system, where the concept of luminosity departs from the conventional approach. They show that a high luminosity can be attained with a rather modest beam power.

Chen, P.; Huang, Z.; Ruth, R.D.

1995-05-01

59

Parallel simulation of beam-beam interaction in high energy accelerators  

SciTech Connect

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

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

2002-02-02

60

Beam profile monitoring at the test beam line at the Compact Linear Collider test facility  

NASA Astrophysics Data System (ADS)

The Compact Linear Collider (CLIC) is a study for a future linear electron-positron collider based on a two-beam acceleration scheme in which a high-intensity drive beam is decelerated in order to provide the power to accelerate the main beam for collision in the TeV range. The power extracted from the drive beam deteriorates the beam quality and increases the energy spread significantly. Monitoring of the beam properties is therefore challenging but essential. These challenges are being addressed experimentally at the CLIC test facility where up to 55% of the power is extracted from the beam in the test beam line, a small-scale version of the CLIC drive-beam decelerator, leaving the beam with a very wide energy profile. For monitoring of the transverse beam profile and Twiss parameters we use optical transition radiation screens and quadrupole scans. The intra-pulse-train energy spectrum before and after deceleration is measured with segmented beam dumps. In this paper we discuss the performance of these diagnostic devices with a particular emphasis on the large energy spread and its effect on the beam imaging techniques, and with a final outlook to the CLIC drive-beam diagnostics.

Olvegård, M.; Adli, E.; Andreazza, W.; Bolzon, B.; Bravin, E.; Chritin, N.; Dabrowski, A.; Döbert, S.; Duraffourg, M.; Lefèvre, T.; Lillestøl, R.; Ziemann, V.

2013-08-01

61

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

62

Polarized muon beams for muon collider  

NASA Astrophysics Data System (ADS)

An option for the production of intense and highly polarized muon beams, suitable for a high-luminosity muon collider, is described briefly. It is based on a multi-channel pion-collection system, narrow-band pion-to-muon decay channels, proper muon spin gymnastics, and ionization cooling to combine all of the muon beams into a single bunch of ultimately low emittance.

Skrinsky, A. N.

1996-11-01

63

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

2004-03-31

64

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

65

Reply to ``Comment on `Beamstrahlung considerations in laser-plasma-accelerator-based linear colliders' ''  

NASA Astrophysics Data System (ADS)

We reply to Lebedev and Nagaitsev’s foregoing Comment [Phys. Rev. ST Accel. Beams 16, 108001 (2013)PRABFM1098-4402]. We disagree with the conclusion of the Comment that scattering imposes a fundamental limitation on plasma-based accelerator technology. Laser-plasma accelerators are compatible with high-luminosity collider concepts.

Schroeder, C. B.; Esarey, E.; Leemans, W. P.

2013-10-01

66

Adiabatic disruption of asymmetric colliding beams  

SciTech Connect

A scheme is considered for enhancing the luminosity of electron-positron colliders. One of the beams is taken to be much denser than the other and effectively becomes a lens for the second beam. The luminosity enhancement afforded by this asymmetric disruption process is estimated analytically. The scheme is severely limited by the kink instability which is characterized by a two-stream dispersion relation, and a constraint on the density of the less dense beam is found for which the instability is gradient stabilized.

Katsouleas, T. [University of Southern California, Los Angeles, CA (United States). Dept. of Electrical Engineering Electrophysics; Wurtele, J.S. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics

1991-12-31

67

Adiabatic disruption of asymmetric colliding beams  

SciTech Connect

A scheme is considered for enhancing the luminosity of electron-positron colliders. One of the beams is taken to be much denser than the other and effectively becomes a lens for the second beam. The luminosity enhancement afforded by this asymmetric disruption process is estimated analytically. The scheme is severely limited by the kink instability which is characterized by a two-stream dispersion relation, and a constraint on the density of the less dense beam is found for which the instability is gradient stabilized.

Katsouleas, T. (University of Southern California, Los Angeles, CA (United States). Dept. of Electrical Engineering Electrophysics); Wurtele, J.S. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics)

1991-01-01

68

Development of a beam condition monitor for use in experiments at the CERN Large Hadron Collider using synthetic diamond  

Microsoft Academic Search

The CERN Large Hadron Collider (LHC) will collide two counter rotating proton beams, each with a store energy about 350MJ; enough to melt 550kg of copper. If there is failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen

L. Fernandez-Hernando; V. Cindro; C. Ilgner; A. Macpherson; A. Oh; H. Pernegger; T. Pritchard; R. Stone; S. Worm

2004-01-01

69

Calculating Beam Breakup in Superconducting Linear Accelerators  

SciTech Connect

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

Geoffrey Krafft; Joseph Bisognano; Sharon Laubach

1990-02-09

70

Electron-Positron Colliding Beam Experiments  

Microsoft Academic Search

Possible experiments with high-energy colliding beams of electrons and positrons are discussed. The role of the proposed two-pion resonance and of the three-pion resonance or bound state is investigated in connection with electron-positron annihilation into pions. The existence of a three-pion bound state would give rise to a very large cross section for annihilation into pi0+gamma. A discussion of the

N. Cabibbo; R. Gatto

1961-01-01

71

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

72

Beam Stop for Electron Accelerator Beam Characterisation  

Microsoft Academic Search

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

Greg Roach; Vic Sharp; James Tickner; Josef Uher

2009-01-01

73

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

74

The polarized electron beam for the SLAC Linear Collider  

SciTech Connect

The SLAC Linear Collider has been colliding a polarized electron beam with an unpolarized positron beam at the Z{sup 0} resonance for the SLD experiment since 1992. An electron beam polarization of close to 80% has been achieved for the experiment at luminosities up to 8 {center_dot} 10{sup 29} cm{sup {minus}2} s{sup {minus}1}. This is the world`s first and only linear collider, and is a successful prototype for the next generation of high energy electron linear colliders. This paper discusses polarized beam operation for the SLC, and includes aspects of the polarized source, spin transport and polarimetry.

Woods, M.

1996-10-01

75

Beam stop for electron accelerator beam characterisation  

Microsoft Academic Search

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

Greg Roach; Vic Sharp; James Tickner; Josef Uher

2008-01-01

76

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

77

When will we know a muon collider is feasible? Status and directions of muon accelerator R&D  

SciTech Connect

Over the last decade there has been significant progress in developing the concepts and technologies needed to produce, capture, accelerate and collide high intensity beams of muons. At present, a high-luminosity multi-TeV muon collider presents a viable option for the next generation of lepton-lepton collider, which is believed to be needed to fully explore high energy physics in the era following the LHC discoveries. This paper briefly reviews the status of the accelerator R&D, addresses the question of the feasibility of a Muon Collider, what needs to be done to prove it and presents projected timeline of the project.

Shiltsev, Vladimir; /Fermilab

2010-03-01

78

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

79

Comment on ``Beamstrahlung considerations in laser-plasma-accelerator-based linear colliders''  

NASA Astrophysics Data System (ADS)

Schroeder, Esarey, Geddes, Benedetti, and Leemans [Phys. Rev. ST Accel. Beams 13, 101301 (2010)PRABFM1098-440210.1103/PhysRevSTAB.13.101301 and Phys. Rev. ST Accel. Beams 15, 051301 (2012)PRABFM1098-440210.1103/PhysRevSTAB.15.051301] have proposed a set of parameters for a TeV-scale collider based on plasma wakefield accelerator principles. In particular, it is sugested that the luminosities greater than 1034cm-2s-1 are attainable for an electron-positron collider. In this Comment we dispute this set of parameters on the basis of first principles. The interactions of accelerating beam with plasma impose fundamental limitations on beam properties and, thus, on attainable luminosity values.

Lebedev, Valeri; Nagaitsev, Sergei

2013-10-01

80

Plasma acceleration of particle beams  

SciTech Connect

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

Katsouleas, T.; Dawson, J. M.

1989-04-05

81

Simulations of coherent beam-beam modes at the Large Hadron Collider  

Microsoft Academic Search

The transverse coherent motion of two colliding proton beams at the Large Hadron Collider is studied by multiparticle tracking. We use the beam-beam force for a Gaussian beam distribution with variable barycenters and rms beam sizes, and optionally include the effect of long-range collisions and external impedance. The simulation yields the coherent and incoherent oscillation frequencies, the emittance growth of

M. P. Zorzano; F. Zimmermann

2000-01-01

82

Beam dynamics problems for a {mu}{sup +}-{mu}{sup -} collider  

SciTech Connect

A {mu}{sup +}-{mu}{sup -} collider requires a high-intensity proton source for {pi}-production, a high-acceptance {pi}-{mu} decay channel, a {mu}-cooling system, a rapid acceleration system, and a high-luminosity collider ring for the collision of short, intense {mu}{sup +}-{mu}{sup -} bunches. Significant beam-dynamics problems exist in each of these systems. These problems and some paths to solutions are discussed in this paper.

Neuffer, D.

1997-06-01

83

Laser cooling of electron beams for linear colliders  

SciTech Connect

A novel method of electron beam cooling is considered which can be used for linear colliders. The electron beam is cooled during collision with focused powerful laser pulse. With reasonable laser parameters (laser flash energy about 10 J) one can decrease transverse beam emittances by a factor about 10 per one stage. The ultimate transverse emittances are much below that given by other methods. Depolarization of a beam during the cooling is about 5--15% for one stage. This method is especially useful for photon colliders and open new possibilities for e{sup +}e{sup {minus}} colliders and x-ray FEL based on high energy linacs.

Telnov, V.

1996-10-01

84

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

85

Calibration beams at the SSC (Superconducting Super Collider)  

Microsoft Academic Search

This paper discusses the following topics on the Superconducting Super Collider: beam specification at calibration halls; high energy booster options with tunnels to surface; switchyard; six beams with high and low power options; switchyard optics for both high and low energy transport; secondary beams; wide band beams; radiation shielding; tagging system; and test and calibration halls.

A. Autin; H. Edwards; J. R. Bensinger; B. Baller; F. Browning; R. Coleman; J. Cooper; D. Cossairt; L. Kula; A. Malensek; R. Stefanski; L. Stutte

1989-01-01

86

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

87

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

88

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 counterpropagating 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 counterpropagating laser intensity a1 {<=} 0.5 for a drive laser intensity of a0 {approx_equal} 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. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); University of Tokyo (Japan); Fubiani, G. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); University of Paris XI, Orsay (France); Geddes, C.G.R. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA (United States); Michel, P.; Toth, C.; Esarey, E.; Schroeder, C.B.; Leemans, W.P. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Tilborg, J. van [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Technische Universiteit Eindhoven (Netherlands)

2004-12-07

89

Field Quality vs Beam Based Corrections in Large Hadron Colliders  

Microsoft Academic Search

After summarising the main types of field errors in su- perconducting magnets the paper discusses limits for cor- recting the magnet field quality via dedicated correction circuits in a collider storage ring and the possibility of ad- justing the powering of such correction circuits via beam based measurements. The performance of any future Large Hadron Collider depends to large extent

O. Bruning

90

ACCELERATING AND COLLIDING POLARIZED PROTONS IN RHIC WITH SIBERIAN SNAKES.  

SciTech Connect

We successfully injected polarized protons in both RHIC rings and maintained polarization during acceleration up to 100 GeV per ring using two Siberian snakes in each ring. Each snake consists of four helical superconducting dipoles which rotate the polarization by 180{sup o} about a horizontal axis. This is the first time that polarized protons have been accelerated to 100 GeV. We report on our experiences during commissioning and operation of collider with polarized protons.

ROSER,T.; AHRENS,L.; ALESSI,J.; BAI,M.; BEEBE - WANG,J.; BRENNAN,J.M.; BROWN,K.A.; BUNCE,G.; CAMERON,P.; COURANT,E.D.; DREES,A.; FISCHER,W.; ET AL

2002-06-02

91

Approaches to Beam Stabilization in X-Band Linear Colliders.  

National Technical Information Service (NTIS)

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 eith...

J. Frisch L. Hendrickson T. Himel T. Markiewicz T. Raubenheimer

2006-01-01

92

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

93

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

94

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

95

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

96

Summary Report of Working Group 5: Electron Beam Driven Plasma Accelerators  

SciTech Connect

Electron beam driven plasma accelerators have seen rapid progress over the last decade. Recent efforts have built on this success by constructing a concept for a plasma wakefield accelerator based linear collider. The needs for any future collider to deliver both energy and luminosity have substantial implications for interpreting current experiments and setting priorities for the future. This working group reviewed current experiments and ideas in the context of the demands of a future collider. The many discussions and presentations are summarized here.

Hogan, Mark J. [SLAC National Accelerator Laboratory Advanced Accelerator Research Department 2575 SandHill Road, Menlo Park, CA 94025 (United States); Conde, Manoel E. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne IL 60439 (United States)

2009-01-22

97

A Concept of Plasma Wake Field Acceleration Linear Collider (PWFA-LC)  

SciTech Connect

Plasma Wake-Field Acceleration (PWFA) has demonstrated acceleration gradients above 50 GeV/m. Simulations have shown drive/witness bunch configurations that yield small energy spreads in the accelerated witness bunch and high energy transfer efficiency from the drive bunch to the witness bunch, ranging from 30% for a Gaussian drive bunch to 95% for a shaped longitudinal profile. These results open the opportunity for a linear collider that could be compact, efficient and more cost effective that the present microwave technologies. A concept of a PWFA-based Linear Collider (PWFA-LC) has been developed and is described in this paper. The drive beam generation and distribution, requirements on the plasma cells, and optimization of the interaction region parameters are described in detail. The R&D steps needed for further development of the concept are also outlined.

Seryi, Andrei; Hogan, Mark; Pei, Shilun; Raubenheimer, Tor; Tenenbaum, Peter; /SLAC; Katsouleas, Tom; /Duke U.; Huang, Chengkun; Joshi, Chan; Mori, Warren; /UCLA; Muggli, Patric; /Southern California U.

2009-10-30

98

New aspects of beam-beam interactions in hadron colliders  

SciTech Connect

Beam-beam phenomena have until now limited the beam currents and luminosity achievable in the Tevatron. injected proton currents are about ten times larger than the anti-proton currents so beam-beam effects have largely acted on the anti-protons and at all stages of the operational cycle. The effects of the anti-protons on the protons have until now been relatively benign but that may change at higher anti-proton currents. After 36 bunches of protons are injected and placed on the proton helix, anti-protons are injected four bunches at a time. After all bunches are injected, acceleration to top energy takes bout 85 seconds. After reaching flat top, the optics around the interaction regions (IRs) is changed to lower {beta}* from 1.6 m to 0.35 m at B0 and D0. The beams are brought into collision by collapsing the separation bumps around the IPs. During a high energy physics store each bunch experiences two head-on collisions with bunches in the opposing beam and seventy long-range interactions. At all other stages of the operational cycle, each bunch experiences only long-range interactions--seventy two in all. Performance limitations from beam-beam effects until now have been primarily due to these long-range interactions. The anti-proton losses at 150 GeV have decreased during the last year mostly due to better control of the orbits, tunes and chromaticities. During this period proton intensities have increased about 50%, thus anti-proton losses at 150 GeV have not been very dependent on proton intensities. Anti-proton and proton losses on the ramp together with proton losses at 150 GeV are the dominant contributors to the Tevatron inefficiency.

Tanaji Sen

2003-06-02

99

Design and construction of vacuum systems for large colliders using superconducting magnets  

SciTech Connect

Vacuum system requirements for proton accelerators and colliders with superconducting megnets are discussed. The vacuum systems for the colliding beam accelerator and the Tevatron are described. (WHK)

Halama, H.J.

1983-01-01

100

Application of a sawtooth surface to accelerator beam chambers with low electron emission rate  

Microsoft Academic Search

One of the latest problems in positron or proton accelerators is a single-beam instability due to an electron cloud around the beam. The instability, for an example, causes a beam size blow up of the positron beam and deteriorates the performance of the electron-positron collider. the seed of the electron cloud is the electrons emitted from the surface of the

Y. Suetsugu; M. Tsuchiya; T. Nishidono; N. Kato; N. Satoh; S. Endo; T. Yokoyama

2003-01-01

101

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

102

Online calculation of the Tevatron collider luminosity using accelerator instrumentation  

SciTech Connect

The luminosity of a collision region may be calculated if one understands the lattice parameters and measures the beam intensities, the transverse and longitudinal emittances, and the individual proton and antiproton beam trajectories (space and time) through the collision region. This paper explores an attempt to make this calculation using beam instrumentation during Run 1b of the Tevatron. The instrumentation used is briefly described. The calculations and their uncertainties are compared to luminosities calculated independently by the Collider Experiments (CDF and D0).

Hahn, A.A.

1997-07-01

103

Laser Cooling of Electron Beams for Linear Colliders  

SciTech Connect

A novel method of electron beam cooling is considered which can be used for linear colliders. The electron beam is cooled during collision with a focused powerful laser pulse. With reasonable laser parameters (laser flash energy about 10J) one can decrease transverse beam emittances by a factor of about 10 per stage. The ultimate transverse emittances are much below those achievable by other methods. Beam depolarization during cooling is about 5{percent}{endash}15{percent} for one stage. This method is especially useful for photon colliders and opens new possibilities for e{sup +}e{sup -} colliders and x-ray free-electron lasers based on high-energy linacs. {copyright} {ital 1997} {ital The American Physical Society}

Telnov, V. [Institute of Nuclear Physics, 630090 Novosibirsk (Russia)

1997-06-01

104

Beam-Beam Study on the Upgrade of Beijing Electron Positron Collider  

SciTech Connect

It is an important issue to study the beam-beam interaction in the design and performance of such a high luminosity collider as BEPCII, the upgrade of Beijing Electron Positron Collider. The weak-strong simulation is generally used during the design of a collider. For performance a large scale tune scan, the weak-strong simulation studies on beam-beam interaction were done, and the geometry effects were taken into account. The strong-strong simulation studies were done for investigating the luminosity goal and the dependence of the luminosity on the beam parameters.

Wang, S.; /Beijing, Inst. High Energy Phys.; Cai, Y.; /SLAC

2006-02-10

105

Beam-Beam Scans Within a Linear Collider Bunch-Train Crossing  

SciTech Connect

Beam-beam deflection scans provide important beam diagnostics at the interaction point of a linear collider. Beam properties such as spot sizes, alignment, and waists are measured by sweeping one beam across the other. Proposed linear colliders use trains of bunches; if beam-beam scans can be done within the time of a bunch-train crossing rather than integrating over the bunch train, the acquisition rate of diagnostic information can be increased and the sensitivity of the scan to pulse-to-pulse jitter and slow drifts reduced. The existence of intra-train deflection feedback provides most of the hardware needed to implement intra-train beam-beam scans for diagnostic purposes. A conceptual design is presented for such beam-beam scans at the Next Linear Collider (NLC).

Smith, S.R.; /SLAC

2006-02-22

106

Synchrotron radiation and beam tube vacuum in a Very Large Hadron Collider, Stage 1 and Stage 2 VLHC  

Microsoft Academic Search

Synchrotron radiation induced photodesorption in particle accelerators may lead to pressure rise and to beam-gas scattering losses, finally affecting the beam lifetime. We discuss the beam tube vacuum in the low field Stage 1 and Stage 2 Very Large Hadron Collider VLHC. Since VLHC Stage 1 has a room temperature beam tube, a non-evaporable getter (NEG St101 strip) pumping system

M. Pivi; W. C. Turner; P. Bauer; P. Limon

2001-01-01

107

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

108

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

109

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

110

Toward design of the Collider Beam Collimation System  

SciTech Connect

A multi-component beam collimation system for the Superconducting Super Collider is described. System choice justification and design requirements are presented. System consists of targets, scrapers, and collimators with appropriate cooling and radiation shielding. Each component has an independent control for positioning and aligning with respect to the beam. Results of beam loss distribution, energy deposition calculations, and thermal analyses, as well as cost estimate, are presented.

Drozhdin, A.; Mokhov, N.; Soundranayagam, R.; Tompkins, J.

1994-02-01

111

Accelerator design of high luminosity electron-hadron collider eRHIC  

NASA Astrophysics Data System (ADS)

The design of future high-energy high-luminosity electron-hadron collider at RHIC called eRHIC is presented. We plan adding energy recovery linacs to accelerate the electron beam to 20 (potentially 30) GeV and to collide the electrons with hadrons in RHIC. The center-of-mass energy of eRHIC will range from 30 to 200 GeV. The luminosity exceeding 1034 cm-2 sec-1 can be achieved in eRHIC using the low-beta interaction region with a 10 mrad crab crossing. The important eRHIC R&D items include the high-current polarized electron source, the coherent electron cooling and the compact magnets for recirculating passes. A natural staging scenario is based on step-by-step increases of the electron beam energy by building-up of eRHIC's SRF linacs.

Ptitsyn, V.; eRHIC Accelerator Design Group

2012-04-01

112

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

Microsoft Academic Search

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

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

2006-01-01

113

Studies of beam dynamics in relativistic klystron two- beam accelerators  

NASA Astrophysics Data System (ADS)

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

Lidia, Steven Michael

114

Proton boron colliding beams for nuclear fusion.  

National Technical Information Service (NTIS)

This paper describes a method of extracting energy from the fusion events occurring during collision of a beam of protons with a beam of ions of (sup 11)B. The two beams circulate in separated and intersecting storage rings of the same geometry and size w...

A. G. Ruggiero

2000-01-01

115

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

NASA Astrophysics Data System (ADS)

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

Lidia, Steven M.

2001-04-01

116

Acceleration of /sup 14/C beams in electrostatic accelerators  

SciTech Connect

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

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

1981-01-01

117

50x50 GeV Muon Collider Beam Collimation  

SciTech Connect

A summary of different techniques and systems to scrape beam halo in a 50 x 50 GeV {mu}{sup +}{mu}{sup -} collider is presented. Such systems are installed in a special utility section with optics specifically designed to meet both the requirements of the scraping system and of injection. Results froma realistic Monte Carlo simulation (STRUCT-MARS) show that a system consisting of steel absorbers several meters in length suppresses halo-induced backgrounds in the collider detector by more than three orders of magnitude. The heat load in superconducting magnets near the scraper system can be reduced to tolerable levels by appropriate collimator design and location. This reduction applies to both injection and collider mode of operation. Also discussed is extraction of halo particles using electrostatic deflectors and bent crys-tals, although neither appears to be effective for a muon collider at this energy.

A.I. Drozhdin, C.J. Johnstone, N.V. Mokhov, A.A. Garen and V.M. Biryukov

1999-04-14

118

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

119

High-gradient two-beam accelerator structure  

Microsoft Academic Search

A new accelerating structure, which is aimed to provide gradient >150 MV\\/m for next generation of multi-TeV linear colliders, is suggested (1-3). The structure is based on periodic system of quasi-optical cavities, which are not coupled with each other. Each of these cavities is excited in several equidistantly-spaced eigen modes by the spatially bunched drive beam in such a way

S. V. Kuzikov; S. Yu. Kazakov; M. E. Plotkin; J. L. Hirshfield

2010-01-01

120

Catalogue of particle-accelerating colliding-wind binaries  

NASA Astrophysics Data System (ADS)

Massive systems made of two or more stars are known to be the site for interesting physical processes - including at least in some cases - particle acceleration. Over the past decade, this topic motivated a particular effort to unveil the properties of these systems and characterize the circumstances responsible for the acceleration of particles and the potential role of pre-supernova massive stars in the production of high energy particles in our Galaxy. Although previous studies on this topic were mostly devoted to processes in general, or to a few individual objects in particular, a unified target-oriented census of particle-accelerating colliding-wind binaries (hereafter PACWBs) does not exist yet. This paper aims at making a general and unified census of these systems, emphasizing their main properties. A general discussion includes energetic considerations along with wind properties in relation with non-thermal emission processes that are likely at work in colliding-wind binaries. Finally, some guidelines for future observational and theoretical studies are drawn.

De Becker, M.; Raucq, F.

2013-10-01

121

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

122

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

123

Wakefield Damping in a Pair of X-Band Accelerators for Linear Colliders  

SciTech Connect

We consider means to damp the wake-field left behind ultra-relativistic charges. In particular, we focus on a pair of travelling wave accelerators operating at an X-band frequency of 11.424 GHz. In order to maximize the efficiency of acceleration, in the context of a linear collider, multiple bunches of charged particles are accelerated within a given pulse of the electromagnetic field. The wake-field left behind successive bunches, if left unchecked, can seriously disturb the progress of trailing bunches and can lead to an appreciable dilution in the emittance of the beam. We report on a method to minimize the influence of the wake-field on trailing bunches. This method entails detuning the characteristic mode frequencies which make-up the electromagnetic field, damping the wake-field, and interleaving the frequencies of adjacent accelerating structures. Theoretical predictions of the wake-field and modes, based on a circuit model, are compared with experimental measurements of the wake-field conducted within the ASSET facility at SLAC. Very good agreement is obtained between theory and experiment and this allows us to have some confidence in designing the damping of wake-fields in a future linear collider consisting of several thousand of these accelerating structures.

Jones, R.M.; Adolphsen, C.E.; Wang, J.W.; Li, Z.; /SLAC

2006-12-18

124

Beam tube vacuum in 100 TeV hadron colliders  

Microsoft Academic Search

Bounds on the beam tube gas pressure and the required pumping speed are estimated for â¼ 2 T low field (LF) and â¼ 12 T high field (HF) 100 TeV center-of-mass hadron colliders. In both cases photodesorption by synchrotron radiation is the dominant source of gas. Assuming beam-gas scattering limited luminosity lifetime five times the IP scattering lifetime, the required

W C Turner

1997-01-01

125

Concentric ring colliding beam machine with dual aperture quadrupoles  

Microsoft Academic Search

IntroductionIn the concentric ring machine [1] the beams collide with a2.3mrad half-angle. The small crossing angle provides forseparation of the bunches near the IR, and is consistentwith the finite aperture of the existing CESR IR quads.The approximately 10s x horizontal separation generatedby the crossing angle is doubled with the help of anelectrostatic deflection so that the beams will clear aseptum.

A A Mikhailichenko; D. Rubin

1996-01-01

126

Test and calibration beams at the Superconducting Super Collider  

Microsoft Academic Search

Development and operation of the research detectors at the Superconducting Super Collider will require extensive testing and calibration. This will be done by exposing the detector elements to controlled sources of particles similar to those which will be encountered when the experiments are taking data. The SSC Laboratory is designing a test beam facility to meet the needs of the

Frank Stocker; Howard Fenker; Ron Schailey

1991-01-01

127

Nonparaxial Mathieu and Weber Accelerating Beams  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

128

Advances in Beam Cooling for Muon Colliders  

SciTech Connect

A six-dimensional (6D) ionization cooling channel based on helical magnets surrounding RF cavities filled with dense hydrogen gas is the basis for the latest plans for muon colliders. This helical cooling channel (HCC) has solenoidal, helical dipole, and helical quadrupole magnetic fields, where emittance exchange is achieved by using a continuous homogeneous absorber. Momentum-dependent path length differences in the dense hydrogen energy absorber provide the required correlation between momentum and ionization loss to accomplish longitudinal cooling. Recent studies of an 800 MHz RF cavity pressurized with hydrogen, as would be used in this application, show that the maximum gradient is not limited by a large external magnetic field, unlike vacuum cavities. Two new cooling ideas, Parametric-resonance Ionization Cooling and Reverse Emittance Exchange, will be employed to further reduce transverse emittances to a few mm-mr, which allows high luminosity with fewer muons than previously imagined. We describe these new ideas as well as a new precooling idea based on a HCC with z dependent fields that is being developed for an exceptional 6D cooling demonstration experiment. The status of the designs, simulations, and tests of the cooling components for a high luminosity, low emittance muon collider will be reviewed.

R.P. Johnson, Y.S. Derbenev

2006-09-01

129

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

130

Theory and suppression of multibunch beam breakup in linear colliders  

SciTech Connect

The authors recently developed an analytic theory of cumulative multibunch beam breakup that includes a linear variation of transverse focusing across the bunch train. The focusing variation saturates the exponential growth of the beam breakup and establishes an algebraic decay of the transverse bunch displacement versus bunch number. In this paper they illustrate how the focusing variation works to suppress multibunch beam breakup, as well as how the mechanism scales with accelerator and beam parameters.

Courtlandt L. Bohn and King-Yuen Ng

2000-08-08

131

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

132

Negative ion beam acceleration and transport experiments  

SciTech Connect

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

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

1985-11-01

133

FIRST BEAM TESTS OF THE MUON COLLIDER TARGET TEST BEAM LINE AT THE AGS.  

SciTech Connect

In this report we will describe the muon collider target test beam line which operates off one branch of the AGS switchyard. The muon collider target test facility is designed to allow a prototype muon collider target system to be developed and studied. The beam requirements for the facility are ambitious but feasible. The system is designed to accept bunched beams of intensities up to 1.6 x 10{sup 13} 24 GeV protons in a single bunch. The target specifications require beam spot sizes on the order of 1 mm, 1 sigma rms at the maximum intensity. We will describe the optics design, the instrumentation, and the shielding design. Results from the commissioning of the beam line will be shown.

BROWN,K.A.; GASSNER,D.; GLENN,J.W.; PRIGL,R.; SIMOS,N.; SCADUTO,J.; TSOUPAS,N.

2001-06-18

134

An Undulator-Based Laser Wakefield Accelerator Electron Beam Diagnostic  

NASA Astrophysics Data System (ADS)

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

Bakeman, Michael S.

135

Symmetrization of the beam-beam interaction in an asymmetric collider  

SciTech Connect

This paper studies the idea of symmetrizing both the lattice and the beams of an asymmetric collider, and discusses why this regime should be within the parametric reach of the design in order to credibly ensure its performance. Also examined is the effectiveness of a simple compensation method using the emittance as a free parameter and that it does not work in all cases. At present, when there are no existing asymmetric colliders, it seems prudent to design an asymmetric collider so as to be similar to a symmetric one (without relying on a particular theory of the asymmetric beam-beam interaction that has not passed tests of fidelity). Nevertheless, one must allow for the maximum possible flexibility and freedom in adjusting those parameters that affect luminosity. Such a parameter flexibility will be essential in tuning the collider to the highest luminosity.

Chin, Y.H.

1990-07-01

136

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

137

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

SciTech Connect

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 on this map. 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). This the map guides one to identify where the crucial elements lie that affect the emittance. If the focusing force of the wakefield is strong when there is a jitter in the position (or laser aiming) of each stage coupled with the spread in the individual particle betatron frequencies, particles experience a phase space mixing. This effect sensitively controls the emittance degradation. They investigate these effects both in a uniform plasma and in a plasma channel. They also study the effect of beam loading. Further, they briefly consider collision point physics issues for a collider expected or characteristic of such a construction based on a scenario for the multi-staged wakefield accelerators.

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

1998-09-01

138

Dark Current Simulation for Linear Collider Accelerator Structures  

SciTech Connect

The dynamics of field-emitted electrons in the traveling wave fields of a constant gradient (tapered) disk-loaded waveguide is followed numerically. Previous simulations have been limited to constant impedance (uniform) structures for sake of simplicity since only the fields in a unit cell is needed. Using a finite element field solver on a parallel computer, the fields in the tapered structure can now be readily generated. We will obtain the characteristics of the dark current emitted from both structure types and compare the two results with and without the effect of secondary electrons. The NLC and JLC detuned structures are considered to study if dark current may pose a problem for high gradient acceleration in the next generation of Linear Colliders.

Ng, C.K.; Li, Z.; Zhan, X.; Srinivas, V.; Wang, J.; Ko, K.; /SLAC

2011-08-25

139

Radio frequency noise effects on the CERN Large Hadron Collider beam diffusion  

NASA Astrophysics Data System (ADS)

Radio frequency (rf) accelerating system noise can have a detrimental impact on the Large Hadron Collider (LHC) performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and rf station dynamics with the bunch length growth [T. Mastorides , Phys. Rev. ST Accel. Beams 13, 102801 (2010)PRABFM1098-440210.1103/PhysRevSTAB.13.102801]. Measurements were conducted at LHC to determine the performance limiting rf components and validate the formalism through studies of the beam diffusion dependence on rf noise. As a result, a noise threshold was established for acceptable performance which provides the foundation for beam diffusion estimates for higher energies and intensities. Measurements were also conducted to determine the low level rf noise spectrum and its major contributions, as well as to validate models and simulations of this system.

Mastoridis, T.; Baudrenghien, P.; Butterworth, A.; Molendijk, J.; Rivetta, C.; Fox, J. D.

2011-09-01

140

Intense beams at the micron level for the Next Linear Collider  

SciTech Connect

High brightness beams with sub-micron dimensions are needed to produce a high luminosity for electron-positron collisions in the Next Linear Collider (NLC). To generate these small beam sizes, a large number of issues dealing with intense beams have to be resolved. Over the past few years many have been successfully addressed but most need experimental verification. Some of these issues are beam dynamics, emittance control, instrumentation, collimation, and beam-beam interactions. Recently, the Stanford Linear Collider (SLC) has proven the viability of linear collider technology and is an excellent test facility for future linear collider studies.

Seeman, J.T.

1991-08-01

141

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

142

The wakefields and loss factors in superconducting accelerating cavities for TESLA collider  

Microsoft Academic Search

The first stage of TTF superconducting electron linac is a in its final state of assembling. Many of superconducting accelerating cavities attained already the planned for collider accelerating fields of 25 MV\\/m. However the problem of cost reduction of TESLA accelerating system is still actual. The propositions concerning modifications in accelerating cavities were signalled at several TESLA Meetings and reported

E. Plawski

1999-01-01

143

Beam tube vacuum in 100 TeV hadron colliders  

SciTech Connect

Bounds on the beam tube gas pressure and the required pumping speed are estimated for {approximately} 2 T low field (LF) and {approximately} 12 T high field (HF) 100 TeV center-of-mass hadron colliders. In both cases photodesorption by synchrotron radiation is the dominant source of gas. Assuming beam-gas scattering limited luminosity lifetime five times the IP scattering lifetime, the required CO equivalent beam tube pressure is 0.25 nTorr for LF and 1.8 nTorr for HF, ambient room temperature equivalent. The CO equivalent pumping speeds required to achieve this pressure within a reasonable beam conditioning time (a few tenths of an operational year at design intensity) are estimated to be {approximately} 300 l/s-m for LF and {approximately} 40 l/s-m for HF. For the LF case with a superferric warm iron magnet, the beam tube is at ambient room temperature and a distributed NEG plus lumped ion or cryo pump system is considered. The size of antechamber needed, ID {approximately} 6 cm, requires that it be located outside the {approximately} 2 cm C-coil magnet gap. Lumped pumps for pumping CH{sub 4} need to be spaced at {approximately} 20 m intervals on the antechamber. For the HF case the likely beam tube temperature is 15--20 K and cryopumping with a beam screen system is considered. The necessary pumping speed can be achieved with slots covering {approximately} 2% of the beam screen surface.

Turner, W.C.

1997-04-01

144

Requirements to beam emittances at photon colliders. Laser cooling of electron beams  

SciTech Connect

Linear colliders offer unique opportunity to study {gamma}{gamma},{gamma}e interactions. Using the laser backscattering method one can obtain {gamma}{gamma} and {gamma}e colliding beams with the energy and luminosity comparable to that in e{sup +}e{sup {minus}} collisions or even higher (due to absence of some beam collision effects). In order to reach ultimate parameters of photon colliders the {open_quotes}geometric{close_quotes} luminosity of initial electron beams should be higher than that in e{sup +}e{sup {minus}} collisions. In this report requirements to beam emittances at photon colliders are analyzed and a novel method of obtaining electron beams with small transverse emittances is considered: the electron beam is cooled during a head-on collision with the focused powerful laser pulse. With reasonable laser parameters (laser flash energy about 10 J) one can decrease the transverse normalized emittances by a factor of 10 per one stage. A limit on the final (after few stages) transverse emittance of the electron beam is much lower than that given by other known methods. {copyright} {ital 1997 American Institute of Physics.}

Telnov, V. [Institute of Nuclear Physics, 630090, Novosibirsk (Russia)

1997-02-01

145

Acceleration of high charge density electron beams in the SLAC linac  

SciTech Connect

The SLAC Linear Collider (SLC) will require both electron and positron beams of very high charge density and low emittance to be accelerated to about 50 GeV in the SLAC 3-km linac. The linac is in the process of being improved to meet this requirement. The program to accelerate an electron beam of high charge density through the first third of the SLC linac is described and the experimental results are discussed. 7 references, 5 figures.

Sheppard, J.C.; Clendenin, J.E.; Jobe, R.K.; Lueth, V.G.; Millich, A.; Ross, M.C.; Seeman, J.T.; Stiening, R.F.

1984-01-01

146

Experimental study of the relativistic klystron two-beam accelerator concept  

SciTech Connect

We recently demonstrated the reacceleration of a modulated electron beam through an induction accelerator cell in support of the two-beam accelerator concept. We present the results of this experiment including amplitude and phase measurements of the extracted microwave power at 11.424 GHz. We also describe our proposed program for constructing a prototype relativistic klystron power source for a 1 TeV linear collider. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Houck, T.; Westenskow, G. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1995-07-05

147

Beam tube vacuum in future superconducting proton colliders  

SciTech Connect

The beam tube vacuum requirements in future superconducting proton colliders that have been proposed or discussed in the literature -- SSC, LHC, and ELN -- are reviewed. The main beam tube vacuum problem encountered in these machines is how to deal with the magnitude of gas desorption and power deposition by synchrotron radiation while satisfying resistivity, impedance, and space constraints in the cryogenic environment of superconducting magnets. A beam tube vacuum model is developed that treats photodesorption of tightly bound H, C, and 0, photodesorption of physisorbed molecules, and the isotherm vapor pressure of H{sub 2}. Experimental data on cold tube photodesorption experiments are reviewed and applied to model calculations of beam tube vacuum performance for simple cold beam tube and liner configurations. Particular emphasis is placed on the modeling and interpretation of beam tube photodesorpiion experiments at electron synchrotron light sources. The paper also includes discussion of the constraints imposed by beam image current heating, the growth rate of the resistive wall instability, and single-bunch instability impedance limits.

Turner, W.

1994-10-01

148

Radio Frequency Noise Effects on the CERN Large Hadron Collider Beam Diffusion  

SciTech Connect

Radio frequency (rf) accelerating system noise can have a detrimental impact on the Large Hadron Collider (LHC) performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and rf station dynamics with the bunch length growth. Measurements were conducted at LHC to determine the performance limiting rf components and validate the formalism through studies of the beam diffusion dependence on rf noise. As a result, a noise threshold was established for acceptable performance which provides the foundation for beam diffusion estimates for higher energies and intensities. Measurements were also conducted to determine the low level rf noise spectrum and its major contributions, as well as to validate models and simulations of this system.

Mastoridis, T.; Baudrenghien, P.; Butterworth, A.; Molendijk, J.; /CERN; Rivetta, C.; Fox, J.D.; /SLAC

2012-04-30

149

To study the emittance dilution in Superconducting Linear Accelerator Design for International Linear Collider (ILC)  

NASA Astrophysics Data System (ADS)

Recently the particle physics community has chosen a single technology for the new accelerator, opening the way for the world community to unite and concentrate resources on the design of an International Linear collider (ILC) using superconducting technology. One of the key operational issues in the design of the ILC will be the preservation of the small beam emittances during passage through the main linear accelerator (linac). Sources of emittance dilution include incoherent misalignments of the quadrupole magnets and rf-structure misalignments. In this work, the study of emittance dilution for the 500-GeV center of mass energy main linac of the Superconducting Linear Accelerator design, based on adaptation of the TESLA TDR design is performed using LIAR simulation program. Based on the tolerances of the present design, effect of two important Beam-Based steering algorithms, Flat Steering and Dispersion Free Steering, are compared with respect to the emittance dilution in the main linac. We also investigated the effect of various misalignments on the emittance dilution for these two steering algorithms.

Ranjan, Kirti; Solyak, Nikolay; Tenenbaum, Peter

2005-04-01

150

Simulation Studies of Beam-Beam Effects of a Ring-Ring Electron-Ion Collider Based on CEBAF  

SciTech Connect

The collective beam-beam effect can potentially cause a rapid growth of beam sizes and reduce the luminosity of a collider to an unacceptably low level. The ELIC, a proposed ultra high luminosity electron-ion collider based on CEBAF, employs high repetition rate crab crossing colliding beams with very small bunch transverse sizes and very short bunch lengths, and collides them at up to 4 interaction points with strong final focusing. All of these features can make the beam-beam effect challenging. In this paper, we present simulation studies of the beam-beam effect in ELIC using a self-consistent strong-strong beam-beam simulation code developed at Lawrence Berkeley National Laboratory. This simulation study is used for validating the ELIC design and for searching for an optimal parameter set.

Yuhong Zhang,Ji Qiang

2009-05-01

151

Beam generation, acceleration, and extraction on a stellatron accelerator  

SciTech Connect

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

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

1994-08-01

152

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

153

Ion colliders  

SciTech Connect

Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the RHIC and LHC injector chains for the heaviest ion species used to date. The RHIC pulsed sputter source (PSC) and Tandem electrostatic accelerator are being replaced by an Electron Beam Ion Source (EBIS), Radio Frequency Quadrupole (RFQ) and short linac [08Ale1]. With EBIS beams of any element can be prepared for RHIC including uranium and spin-polarized 3He. At CERN an ECR ion source is used, followed by an RFQ and Linac. The ions are then accumulated, electron cooled, and accelerated in LEIR. After transfer to and acceleration in the PS, ion beams are injected into the SPS.

Fischer, W.

2011-12-01

154

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

155

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

156

Weak-strong beam-beam simulations for the Large Hadron Collider  

Microsoft Academic Search

A weak-strong simulation code is used to study the single-particle stability in the presence of triplet field errors, head-on collisions, and long-range beam-beam interactions at the Large Hadron Collider. We present the dependence of the simulated transverse diffusion rate on various parameters, such as starting amplitude, working point in tune diagram, crossing angle, beta function at the interaction points (IPs),

Y. Papaphilippou; F. Zimmermann

1999-01-01

157

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

158

Review of linear collider beam-beam interaction  

SciTech Connect

Three major effects from the interaction of /ital e//sup +//ital e/minus// beams --- disruption, beamstrahlung, and electron-positron pair creation --- are reviewed. For the disruption effects we discuss the luminosity enhancement factor, the maximum and /ital 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 computor 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/minus/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.

Chen, P.

1989-04-01

159

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

160

Synchrotron radiation and beam tube vacuum in a Very Large Hadron Collider, Stage 1 and Stage 2 VLHC  

SciTech Connect

Synchrotron radiation induced photodesorption in particle accelerators may lead to pressure rise and to beam-gas scattering losses, finally affecting the beam lifetime [1]. We discuss the beam tube vacuum in the low field Stage 1 and Stage 2 Very Large Hadron Collider VLHC. Since VLHC Stage 1 has a room temperature beam tube, a non-evaporable getter (NEG St101 strip) pumping system located inside a pumping antechamber, supplemented by lumped ion pumps for pumping methane is considered. In Stage 2, the {approx}100 K beam screen, or liner, illuminated by the synchrotron radiation, is inserted into the magnet cold bore. Cryo-pumping is provided by the cold bore kept at 4.2 K, through slots covering the beam screen surface. Possible beam conditioning scenarios are presented for reaching design intensity, both for Stage 1 and 2. The most important results are summarized in this paper.

Pivi, M.; Turner, W.C.; Bauer, P.; Limon, P.

2001-06-30

161

Analysis of Gaussian beam and Bessel beam driven laser accelerators  

SciTech Connect

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

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

1999-10-01

162

Accidental beam loss in superconducting accelerators: Simulations, consequences of accidents and protective measures  

Microsoft Academic Search

The consequences of an accidental beam loss in superconducting accelerators and colliders of the next generation range from the mundane to rather dramatic, i.e., from superconducting magnet quench, to overheating of critical components, to a total destruction of some units via explosion. Specific measures are required to minimize and eliminate such events as much as practical. In this paper we

A. Drozhdin; N. Mokhov; B. Parker

1994-01-01

163

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

NASA Astrophysics Data System (ADS)

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

Joshi, C.

2007-05-01

164

Damped accelerator structures for future linear e/sup/plus minus// colliders  

SciTech Connect

This paper describes preliminary work on accelerator structures for future TeV linear colliders which use trains of e/sup +-/ bunches to reach the required luminosity. These bunch trains, if not perfectly aligned with respect to the accelerator axis, induce transverse wake field modes into the structure. Unless they are sufficiently damped, these modes cause cummulative beam deflections and emittance growth. The envisaged structures, originally proposed by R. B. Palmer, are disk-loaded waveguides in which the disks are slotted radially into quadrants. Wake field energy is coupled via the slots and double-ridged waveguides into a lossy region which is external to the accelerator structure. The requirement is that the Q of the HEM/sub 11/ mode be reduced to a value of less than 30. The work done so far includes MAFIA code computations and low power rf measurements to study the fields. A four-cavity 2..pi../3 mode standing-wave structure has been built to find whether the slots lower the electric breakdown thresholds below those reached with conventional disk-loaded structures. We set out to assess the microwave properties of the structure and the problems which might be encountered in fabricating it. 4 refs., 7 figs.

Deruyter, H.; Hoag, H.A.; Lisin, A.V.; Loew, G.A.; Palmer, R.B.; Paterson, J.M.; Rago, C.E.; Wang, J.W.

1989-03-01

165

Design of a relativistic klystron two-beam accelerator prototype  

SciTech Connect

We are designing an experiment to study physics, engineering, and costing issues of an extended Relativistic Klystron Two-Beam Accelerator (RK-TBA). The experiment is a prototype for an RK-TBA based microwave power source suitable for driving a 1 TeV linear collider. Major components of the experiment include a 2.5-MV, 1.5-kA electron source, a 11.4-GHz modulator, a bunch compressor, and a 8-m extraction section. The extraction section will be comprised of 4 traveling-wave output structures, each generating about 360 MW of rf power. Induction cells will be used in the extraction section to maintain the average beam energy at 5 MeV. Status of the design is presented.

Westenskow, G.; Caporaso, G.; Chen, Y. [and others

1995-10-01

166

Design of a relativistic Klystron Two-Beam Accelerator Prototype  

SciTech Connect

We are designing an experiment to study physics, engineering, and costing issues of an extended Relativistic Klystron Two-Beam Accelerator (RK-TBA). The experiment is a prototype for an RK-TBA based microwave power source suitable for driving a 1 TeV linear collider. Major components of the experiment include a 2.5-MV, 1.5-kA electron source, a 11.4-GHz modulator, a bunch compressor, and a 8-m extraction section. The extraction section will be comprised of 4 traveling-wave output structures, each generating about 360 MW of rf power. Induction cells will be used in the extraction section to maintain the average beam energy at 5 MeV. Status of the design is presented.

Westenskow, G.; Caporaso, G.; Chen, Y.; Houck, T.; Yu, S.; Chattopadhyay, S.; Henestroza, E.; Li, H.; Peters, C.; Reginato, L.; Sessler, Andrew M.

1995-04-01

167

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 y} = 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, Marc C

2002-07-03

168

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

169

Beam instrumentation and precision timing equipment for the SSC accelerator complex  

SciTech Connect

This article is intended to provide an introduction to the beam instrumentation systems and the precision timing system of the SSC Laboratory. The Beam Instrumentation Department of the SSC Accelerator Systems Division is responsible for the design of these systems for the Collider rings and the injecter accelerators. Status and plans are briefly described. The signal sensors and low level signal processing electronics of the beam instrumentation systems are the eyes and ears into the world of the proton beam. Situated between that invisible beam and the accelerator operator, they monitor and measure the behavior and performance of the otherwise intangible protons as they are guided and accelerated through the Linac and the injecter synchrotrons, and finally stored in the Collider rings. The precision timing system provides the vital time references required to synchronize critical accelerator hardware functions, beam manipulations, and data acquisition over the geographical extent of the Supercollider complex. Several fundamental timing signals are distributed over dedicated fiber optic networks. Special programmable electronic modules process the timing information to provide precisely timed outputs to control the many accelerator systems and devices.

Webber, R.

1993-04-01

170

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

171

The influence of accelerator physics on the magnet design of a very large hadron collider  

Microsoft Academic Search

We present a study of the influence of accelerator physics on the design of magnets for very high energy hadron colliders. The limiting specifications of a particular VLHC model are estimated, and their effect on the design of the accelerator magnets is determined using simulations and scaling laws for magnet aperture, field quality, cryogenic and vacuum properties and cost. We

P. Bauer; A. Dietrich; G. W. Foster; V. V. Kashikhin; P. J. Limon; V. Shiltsev; N. Solyak

2002-01-01

172

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

Microsoft Academic Search

The authors present the history and 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 m in circumference, and having 108 buckets around the ring. Acceleration programs, each 50-ms long, take place at a rate of 10\\/s. The beta change

C. C. Friedrichs; L. Walling; B. M. Campbell

1991-01-01

173

Pulsed power accelerators for particle beam fusion  

SciTech Connect

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

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

1980-01-01

174

International Linear Collider Accelerator Physics R&D  

SciTech Connect

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

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

2008-09-03

175

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

176

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

177

Design of the Beam Delivery System for the Inernational Linear Collider.  

National Technical Information Service (NTIS)

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...

A. Seryi F. Asiri J. Amann K. Bane P. Bellomo R. Arnold

2007-01-01

178

SLAC electron-positron colliders: present and future  

SciTech Connect

Stanford University's colliding beam program is outlined, including the SPEAR and PEP colliders and the SLAC linear collider. The accelerator developments to be pursued on these facilities are discussed, as well as advanced accelerator research and development. The items covered in the advanced accelerator research include beamstrahlung, stability requirements, breakdown limits, and power sources. (LEW)

Richter, B.

1986-09-01

179

Experimental Demonstration of Colliding-Beam-Lifetime Improvement by Electron Lenses  

NASA Astrophysics Data System (ADS)

We report the successful application of space-charge forces of a low-energy electron beam for improvement of particle lifetime determined by beam-beam interaction at a high-energy collider. In our experiments, an electron lens, a novel instrument developed for the beam-beam compensation, was set on a 980-GeV proton bunch at the Fermilab Tevatron proton-antiproton collider. The proton-bunch losses due to its interaction with the antiproton beam were reduced by a factor of 2 when the electron lens was operating. We describe the principle of electron lens operation and present experimental results.

Shiltsev, V.; Alexahin, Y.; Bishofberger, K.; Kamerdzhiev, V.; Kuznetsov, G.; Zhang, X.-L.

2007-12-01

180

Electron Cloud Effects in Cornell Electron Storage Ring Test Accelerator and International Linear Collider Damping Ring  

NASA Astrophysics Data System (ADS)

In this paper, the effects of electron cloud are discussed for the ultra low emittance positron beam in Cornell Electron Storage Ring Test Accelerator (Cesr-TA) and the International Linear Collider (ILC) damping ring. We have investigated the electron-cloud instabilities with Cesr-TA which has been operating to experiment for the ILC damping ring with different positron beam energies: 2 and 5 GeV. The electron phase factor, ?e,y?z/c, is given differently to each case. The single-bunch instability is investigated with a simulation based on the strong-strong model by using the simplified lattice. The threshold densities obtained by simulations agree with the predicted values within a factor 1.3. We investigate the effects of the bunch-by-bunch feedback of about 50 turns and non-zero dispersion. The simulation results show that the feedback system suppresses the dipole motion and increases the threshold density in 2 GeV case, but is less effective in 5 GeV case. The threshold densities are degraded with non-zero dispersion in both cases, but the rates of degradation appear differently. We discuss an incoherent emittance growth using the realistic lattice model for Cesr-TA. Below the threshold, the incoherent emittance growth may not be serious in Cesr-TA and the ILC damping ring.

Jin, Hyunchang; Yoon, Moohyun; Ohmi, Kazuhito; Flanagan, John W.; Palmer, Mark A.

2011-02-01

181

Accelerated radioactive beams from REX-ISOLDE  

NASA Astrophysics Data System (ADS)

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

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

2003-05-01

182

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

Microsoft Academic Search

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,

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

2010-01-01

183

Physical Review Special Topics : Accelerators and Beams  

NSDL National Science Digital Library

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

184

Electron Beam Ion Sources for Accelerator Applications  

Microsoft Academic Search

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

Edward N. Beebe

1996-01-01

185

Use of dual rf systems to accelerate large longitudinal emittance intense beam in a synchrotron  

NASA Astrophysics Data System (ADS)

Preserving the beam brightness and emittance during acceleration for high energy collider operation is a long-standing challenge for synchrotron injectors. Radio-frequency manipulation schemes used to produce bright bunches in these synchrotrons are often responsible for both beam loss and for the emittance dilution; the impact of such effects becomes the main obstacle to improve the collider luminosity. We have developed a scheme for acceleration of intense beam bunches of large longitudinal emittance using two rf systems. The development of such a method primarily came about to improve the overall injection to extraction efficiency of the antiproton beam in the Main Injector used for the proton-antiproton collider operation of the Tevatron at Fermilab. This technique is quite general and can be applied at other facilities. Multiparticle beam dynamics simulations of the scheme have shown that one can eliminate the beam loss and minimize the emittance growth. The scheme has been demonstrated with beam experiments in the Main Injector using the 2.5 and 53 MHz rf systems with harmonic ratio of 1?21.

Bhat, C. M.; MacLachlan, J. A.; Wu, V.

2007-03-01

186

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

187

Flip-Flop Modes in Symmetric and Asymmetric Colliding-Beam Storage Rings  

SciTech Connect

A model of self-consistent beam blow-up in a colliding beam storage ring is described which explains the appearance of flip-flop modes in both symmetric and asymmetric beam systems. It derives the strong-strong steady-states and their stabilities from the weak-strong behavior. This model agrees well with the observed flip-flop behavior in storage rings, including the hysteresis seen when the beams are flipped from one asymmetric steady state to the other. It can be used to predict the behavior of proposed facilities in which the two colliding beams are characterized by different parameters.

Tennyson, J.L.

1989-08-01

188

A High Power Pulse System for the Beam Extraction from CERN's Large Hadron Collider  

Microsoft Academic Search

CERN, the European Organization for Nuclear Research, is close to starting operation of the large hadron collider (LHC). A beam dumping system must protect the LHC machine from damage, by reliably and safely extracting and absorbing the circulating beams when requested. For this purpose a beam extraction system has been designed, built, installed and tested. It is composed of 15

E. Carlier; F. Castronuovo; L. Ducimetiere; E. B. Vossenberg

2008-01-01

189

The 12GeV\\/c beam transfer and absorber lines for the Superconducting Super Collider  

Microsoft Academic Search

The beam optics of the 12-GeV\\/c proton beam transfer line between the Low Energy Booster (LEB) and the Medium Energy Booster (MEB) at the Superconducting Super Collider is presented. The beam is extracted from the LEB vertically and is injected into the MEB through a vertical Lambertson magnet and a horizontal kicker. The beamline has high flexibility for amplitude and

N. Mao; J A McGill; R. Gerig; K. Brown

1994-01-01

190

Head-on beam-beam compensation investigation in an electron-ion collider using weak-strong simulations  

NASA Astrophysics Data System (ADS)

The luminosity of the ring-ring version of the proposed electron-ion collider eRHIC is limited by the beam-beam effect on the electrons. Once the beam-beam limit is reached, the luminosity no longer increases linearly with the bunch intensity of the ion beam, but begins to saturate and even drops again if the beam-beam tuneshift is increased further. To overcome this limitation we investigate a compensation scheme with an electron lens acting on the electron beam. Using weak-strong simulations we find a possible luminosity increase of about a factor 2.

Montag, Christoph; Fischer, Wolfram

2009-08-01

191

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

192

Protection of the CERN Large Hadron Collider  

Microsoft Academic Search

The Large Hadron Collider (LHC) at CERN will collide two counter-rotating proton beams, each with an energy of 7 TeV. The energy stored in the superconducting magnet system will exceed 10 GJ, and each beam has a stored energy of 362 MJ which could cause major damage to accelerator equipment in the case of uncontrolled beam loss. Safe operation of

R. Schmidt; R. Assmann; E. Carlier; B. Dehning; R. Denz; B. Goddard; E. B. Holzer; V. Kain; B. Puccio; B. Todd; J. Uythoven; J. Wenninger; M. Zerlauth

2006-01-01

193

Production of an Accelerated Oxygen-14 Beam  

SciTech Connect

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

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

2002-05-03

194

Achievement of Ultralow Emittance Beam in the Accelerator Test Facility Damping Ring  

NASA Astrophysics Data System (ADS)

For high luminosity in electron-positron linear colliders, it is essential to generate low vertical emittance beams. We report on the smallest vertical emittance achieved in single-bunch-mode operation of the Accelerator Test Facility, which satisfies the requirement of the x-band linear collider. The emittances were measured with a laser-wire beam-profile monitor installed in the damping ring. The bunch length and the momentum spread of the beam were also recorded under the same conditions. The smallest vertical rms emittance measured at low intensity is 4pm at a beam energy of 1.3GeV, which corresponds to the normalized emittance of 1.0×1.0-8 m. It increases by a factor of 1.5 for a bunch intensity of 1010 electrons. The measured data agreed to the calculation of intrabeam scattering within much better than a factor of 2.

Honda, Y.; Kubo, K.; Anderson, S.; Araki, S.; Bane, K.; Brachmann, A.; Frisch, J.; Fukuda, M.; Hasegawa, K.; Hayano, H.; Hendrickson, L.; Higashi, Y.; Higo, T.; Hirano, K.; Hirose, T.; Iida, K.; Imai, T.; Inoue, Y.; Karataev, P.; Kuriki, M.; Kuroda, R.; Kuroda, S.; Luo, X.; McCormick, D.; Matsuda, M.; Muto, T.; Nakajima, K.; Naito, Takashi; Nelson, J.; Nomura, M.; Ohashi, A.; Omori, T.; Okugi, T.; Ross, M.; Sakai, H.; Sakai, I.; Sasao, N.; Smith, S.; Suzuki, Toshikazu; Takano, M.; Taniguchi, T.; Terunuma, N.; Turner, J.; Toge, N.; Urakawa, J.; Vogel, V.; Woodley, M.; Wolski, A.; Yamazaki, I.; Yamazaki, Yoshio; Yocky, G.; Young, A.; Zimmermann, F.

2004-02-01

195

Achievement of ultralow emittance beam in the accelerator test facility damping ring.  

PubMed

For high luminosity in electron-positron linear colliders, it is essential to generate low vertical emittance beams. We report on the smallest vertical emittance achieved in single-bunch-mode operation of the Accelerator Test Facility, which satisfies the requirement of the x-band linear collider. The emittances were measured with a laser-wire beam-profile monitor installed in the damping ring. The bunch length and the momentum spread of the beam were also recorded under the same conditions. The smallest vertical rms emittance measured at low intensity is 4 pm at a beam energy of 1.3 GeV, which corresponds to the normalized emittance of 1.0x1.0(-8) m. It increases by a factor of 1.5 for a bunch intensity of 10(10) electrons. The measured data agreed to the calculation of intrabeam scattering within much better than a factor of 2. PMID:14995314

Honda, Y; Kubo, K; Anderson, S; Araki, S; Bane, K; Brachmann, A; Frisch, J; Fukuda, M; Hasegawa, K; Hayano, H; Hendrickson, L; Higashi, Y; Higo, T; Hirano, K; Hirose, T; Iida, K; Imai, T; Inoue, Y; Karataev, P; Kuriki, M; Kuroda, R; Kuroda, S; Luo, X; McCormick, D; Matsuda, M; Muto, T; Nakajima, K; Naito, Takashi; Nelson, J; Nomura, M; Ohashi, A; Omori, T; Okugi, T; Ross, M; Sakai, H; Sakai, I; Sasao, N; Smith, S; Suzuki, Toshikazu; Takano, M; Taniguchi, T; Terunuma, N; Turner, J; Toge, N; Urakawa, J; Vogel, V; Woodley, M; Wolski, A; Yamazaki, I; Yamazaki, Yoshio; Yocky, G; Young, A; Zimmermann, F

2004-02-06

196

Issues and experience with controlling beam loss at the Tevatron collider  

SciTech Connect

Controlling beam loss in the Tevatron collider is of great importance because of the delicate nature of the cryogenic magnet system and the collider detectors. Maximizing the physics potential requires optimized performance as well as protection of all equipment. The operating history of the Tevatron has significantly influenced the way losses are managed. The development of beam loss management in the Tevatron will be presented.

Annala, Gerald; /Fermilab

2007-07-01

197

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

198

Toward automatic control of particle accelerator beams  

SciTech Connect

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

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

1988-01-01

199

The Computer Program LIAR for Beam Dynamics Calculations in Linear Accelerators  

SciTech Connect

Linear accelerators are the central components of the proposed next generation of linear colliders. They need to provide acceleration of up to 750 GeV per beam while maintaining very small normalized emittances. Standard simulation programs, mainly developed for storage rings, do not meet the specific requirements for high energy linear accelerators. We present a new program LIAR ('LInear Accelerator Research code') that includes wakefield effects, a 6D coupled beam description, specific optimization algorithms and other advanced features. Its modular structure allows to use and to extend it easily for different purposes. The program is available for UNIX workstations and Windows PC's. It can be applied to a broad range of accelerators. We present examples of simulations for SLC and NLC.

Assmann, R.W.; Adolphsen, C.; Bane, K.; Raubenheimer, T.O.; Siemann, R.H.; Thompson, K.; /SLAC

2011-08-26

200

600 kV modulator design for the SLAC Next Linear Collider Test Accelerator.  

National Technical Information Service (NTIS)

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 (mu)s, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a micr...

K. Harris J. de Lamare V. Nesterov R. Cassel

1992-01-01

201

Relativistic Klystron Two-Beam Accelerator studies at the RTA test facility  

SciTech Connect

A prototype rf power source based on the Relativistic Klystron Two- Beam Accelerator (RK-TBA) concept is being constructed at LBNL to study physics, engineering, and costing issues. The prototype, called RTA, is described and compared to a full scale design appropriate for driving the Next Linear Collider. Specific details of the induction core test and pulsed power system are presented. Details of the 1-MeV, 1.2-kA induction gun currently under construction are described.

Westenskow, G.A.; Houck, T.L. [Lawrence Livermore National Lab., CA (United States); Anderson, D. [Lawrence Berkeley National Lab., CA (United States)] [and others

1996-08-16

202

Transverse instabilities in a relativistic klystron two-beam accelerator  

SciTech Connect

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

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

1992-08-01

203

Studies of beam dynamics in relativistic klystron two-beam accelerators  

SciTech Connect

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

Lidia, Steven M.

1999-11-01

204

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

205

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

206

Numerical Verification of the Power Transfer and Wakefield Coupling in the Clic Two-Beam Accelerator  

SciTech Connect

The Compact Linear Collider (CLIC) provides a path to a multi-TeV accelerator to explore the energy frontier of High Energy Physics. Its two-beam accelerator (TBA) concept envisions complex 3D structures, which must be modeled to high accuracy so that simulation results can be directly used to prepare CAD drawings for machining. The required simulations include not only the fundamental mode properties of the accelerating structures but also the Power Extraction and Transfer Structure (PETS), as well as the coupling between the two systems. Time-domain simulations will be performed to understand pulse formation, wakefield damping, fundamental power transfer and wakefield coupling in these structures. Applying SLAC's parallel finite element code suite, these large-scale problems will be solved on some of the largest supercomputers available. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel two-beam accelerator scheme.

Candel, Arno; Li, Z.; Ng, C.; Rawat, V.; Schussman, G.; Ko, K.; /SLAC; Syratchev, I.; Grudiev, A.; Wuensch, W.; /CERN

2011-08-19

207

Beam optics of LEB-MEB transfer line for Superconducting Super Collider  

Microsoft Academic Search

The beam optics of the transfer line between the Low Energy Booster (LEB) and the Medium Energy Booster (MEB) at the Superconducting Super Collider Laboratory is presented. The 12 GeV\\/c proton beam is extracted from the LEB and injected into the MEB at strictly defined extraction and injection points. The beamline has a high flexibility for ? and ? function

Naifeng Mao; John A. McGill; Karl L. Brown; Rodney E. Gerig

1993-01-01

208

The 23-GEV/C Beam Transfer and Absorber Lines for the Superconducting Super Collider  

SciTech Connect

The beam optics of the 12-GeV/c proton beam transfer line between the Low Energy Booster (LEB) and the Medium Energy Booster (MEB) at the Superconducting Super Collider is presented. The beam is extracted from the LEB vertically and is injected into the MEB through a vertical Lambertson magnet and a horizontal kicker. The beamline has high flexibility for amplitude and dispersion function matching. Effects of various errors in the transfer line are studied, and a beam position correction scheme is proposed. The beam optics of the 12-GeV/c absorber line transporting the beam from the LEB to an absorber during the LEB commissioning is also presented.

Brown, Karl

2003-07-07

209

The 12-GeV/c beam transfer and absorber lines for the Superconducting Super Collider  

NASA Astrophysics Data System (ADS)

The beam optics of the 12-GeV/c proton beam transfer line between the Low Energy Booster (LEB) and the Medium Energy Booster (MEB) at the Superconducting Super Collider is presented. The beam is extracted from the LEB vertically and is injected into the MEB through a vertical Lambertson magnet and a horizontal kicker. The beamline has high flexibility for amplitude and dispersion function matching. Effects of various errors in the transfer line are studied, and a beam position correction scheme is proposed. The beam optics of the 12-GeV/c absorber line transporting the beam from the LEB to an absorber during the LEB commissioning is also presented.

Mao, N.; McGill, J.; Gerig, R.; Brown, K.

1994-08-01

210

Straw man 900-1000 GeV crystal extraction test beam for Fermilab collider operation  

SciTech Connect

A design for a 900-1000 GeV, 100 khz parasitic test beam for use during collider operations has been developed. The beam makes use of two bent crystals, one for extraction and the other one for redirecting the beam in to the present Switchyard beam system. The beam requires only a few modifications in the A0 area and largely uses existing devices. It should be straight-forward to modify one or two beam lines in the fixed target experimental areas to work above 800 GeV. Possibilities for improvements to the design,to operate at higher fluxes are discussed.

Carrigan, R.A. Jr.

1996-10-01

211

Beam physics developments for a rare isotope accelerator  

Microsoft Academic Search

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

Mauricio Portillo

2002-01-01

212

Characterisation of electron beams from laser-driven particle accelerators  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

213

Beam Dynamics Measurements for the SLAC Laser Acceleration Experiment  

SciTech Connect

The NLC Test Accelerator (NLCTA) was built to address beam dynamics issues for the Next Linear Collider and beyond. An S-Band RF gun, diagnostics and low energy spectrometer (LES) at 6 MeV together with a large-angle extraction line at 60 MeV have now been built and commissioned for the laser acceleration experiment, E163. Following a four quad matching section after the NLCTA chicane, the extraction section is followed by another matching section, final focus and buncher. The laser-electron interaction point (IP) is followed by a broad range, high resolving power spectrometer (HES) for electron bunch analysis. Optical symmetries in the design of the 25.5 degree extraction line provide 1:1 phase space transfer without sextupoles for a large, 6D phase space volume and range of input conditions. Spot sizes down to a few microns at the IP (HES object) allow testing microscale structures with high resolving power at the HES image. Tolerances, tuning sensitivities, diagnostics and the latest commissioning results are discussed and compared to design expectations.

Colby, E.; Ischebeck, R.; McCormick, D.; McGuinness, C.; Nelson, J.; Noble, R.; Sears, C.; Siemann, R.; Spencer, J.; /SLAC; Plettner, T.; /Stanford U., Phys. Dept.

2007-07-23

214

High-gradient two-beam accelerator structure  

Microsoft Academic Search

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

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

2010-01-01

215

BEAM-BASED NON-LINEAR OPTICS CORRECTIONS IN COLLIDERS.  

SciTech Connect

A method has been developed to measure and correct operationally the non-linear effects of the final focusing magnets in colliders, that gives access to the effects of multi-pole errors by applying closed orbit bumps, and analyzing the resulting tune and orbit shifts. This technique has been tested and used during 4 years of RHIC (the Relativistic Heavy Ion Collider at BNL) operations. I will discuss here the theoretical basis of the method, the experimental set-up, the correction results, the present understanding of the machine model, the potential and limitations of the method itself as compared with other non-linear correction techniques.

PILAT, R.; LUO, Y.; MALITSKY, N.; PTITSYN, V.

2005-05-16

216

Time evolution of the luminosity of colliding heavy-ion beams in BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider  

SciTech Connect

We have studied the time evolution of the heavy ion luminosity and bunch intensities in the Relativistic Heavy Ion Collider (RHIC), at BNL, and in the Large Hadron Collider (LHC), at CERN. First, we present measurements from a large number of RHIC stores (from Run 7), colliding 100 GeV/nucleon {sup 197}Au{sup 79}+ beams without stochastic cooling. These are compared with two different calculation methods. The first is a simulation based on multi-particle tracking taking into account collisions, intrabeam scattering, radiation damping, and synchrotron and betatron motion. In the second, faster, method, a system of ordinary differential equations with terms describing the corresponding effects on emittances and bunch populations is solved numerically. Results of the tracking method agree very well with the RHIC data. With the faster method, significant discrepancies are found since the losses of particles diffusing out of the RF bucket due to intrabeam scattering are not modeled accurately enough. Finally, we use both methods to make predictions of the time evolution of the future {sup 208}Pb+{sup 82+} beams in the LHC at injection and collision energy. For this machine, the two methods agree well.

Bruce, R.; Blaskiewicz, M.; Jowett, J.M.; Fischer, W.

2010-09-07

217

Time evolution of the luminosity of colliding heavy-ion beams in BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider  

NASA Astrophysics Data System (ADS)

We have studied the time evolution of the heavy-ion luminosity and bunch intensities in the Relativistic Heavy Ion Collider (RHIC) at BNL, and in the Large Hadron Collider (LHC) at CERN. First, we present measurements from a large number of RHIC stores (from run-7), colliding 100GeV/nucleon Au79+197 beams without stochastic cooling. These are compared with two different calculation methods. The first is a simulation based on multiparticle tracking taking into account collisions, intrabeam scattering, radiation damping, and synchrotron and betatron motion. In the second, faster, method, a system of ordinary differential equations with terms describing the corresponding effects on emittances and bunch populations is solved numerically. Results of the tracking method agree very well with the RHIC data. With the faster method, significant discrepancies are found since the losses of particles diffusing out of the rf bucket due to intrabeam scattering are not modeled accurately enough. Finally, we use both methods to make predictions of the time evolution of the future Pb82+208 beams in the LHC at injection and collision energy. For this machine, the two methods agree well.

Bruce, R.; Jowett, J. M.; Blaskiewicz, M.; Fischer, W.

2010-09-01

218

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

219

The muon collider (Sandro's Snake)  

NASA Astrophysics Data System (ADS)

We describe a feasibility study for the design of a muon collider. We have adopted a scheme where steps of cooling and acceleration are entwined. We have indeed found convenient to accelerate the beam as fast as possible to increase its chances of survival, and necessary to dilute the action of cooling throughout the entire accelerating process to make it more effective affordable. As an example, we describe a muon collider at the energy of 250 GeV per beam and a luminosity of 4×1025 cm-2s-1. We have adopted an extrapolation of the stochastic cooling method for the reduction of the beam emittance.

Ruggiero, A. G.

1992-07-01

220

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

221

Investigation of Electron Beam Behavior in a Linear Induction Accelerator.  

National Technical Information Service (NTIS)

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

L. A. Merkulov

1985-01-01

222

High-gradient two-beam accelerator structure  

NASA Astrophysics Data System (ADS)

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

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

2010-07-01

223

Novel accelerators employing high-current electron beams numerical simulations  

SciTech Connect

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

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

1986-01-01

224

Design study of longitudinal dynamics of the drive beam in 1 TeV relativistic klystron two-beam accelerator  

SciTech Connect

In this paper the authors present a design study on the longitudinal dynamics of a relativistic klystron two-beam accelerator (RK-TBA) scheme which has been proposed as a power source candidate for a 1 TeV next linear collider (NLC). They address the issue of maintaining stable power output at desired level for a 300-m long TBA with 150 extraction cavities and present their simulation results to demonstrate that it can be achieved by inductively detuning the extraction cavities to counter the space charge debunching effect on the drive beam. They then carry out simulation study to show that the beam bunches desired by the RK-TBA can be efficiently obtained by first chopping an initially uniform beam of low energy into a train of beam bunches with modest longitudinal dimension and then using the {open_quotes}adiabatic capture{close_quotes} scheme to bunch and accelerate these beam bunches into tight bunches at the operating energy of the drive beam. The authors have also examined the {open_quotes}after burner{close_quotes} scheme which is implemented in their RK-TBA design for efficiency enhancement.

Li, H.; Yu, S.S.; Sessler, A.M.

1994-10-01

225

Design study of longitudinal dynamics of the drive beam in 1 TeV relativistic klystron two-beam accelerator  

NASA Astrophysics Data System (ADS)

In this paper the authors present a design study on the longitudinal dynamics of a relativistic klystron two-beam accelerator (RK-TBA) scheme which has been proposed as a power source candidate for a 1 TeV next linear collider (NLC). They address the issue of maintaining stable power output at desired level for a 300-m long TBA with 150 extraction cavities and present their simulation results to demonstrate that it can be achieved by inductively detuning the extraction cavities to counter the space charge debunching effect on the drive beam. They then carry out simulation study to show that the beam bunches desired by the RK-TBA can be efficiently obtained by first chopping an initially uniform beam of low energy into a train of beam bunches with modest longitudinal dimension and then using the 'adiabatic capture' scheme to bunch and accelerate these beam bunches into tight bunches at the operating energy of the drive beam. The authors have also examined the 'after burner' scheme which is implemented in their RK-TBA design for efficiency enhancement.

Li, H.; Yu, S. S.; Sessler, A. M.

1994-10-01

226

Cooling of accelerator beams to improve focal properties  

Microsoft Academic Search

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

T. Katayama

1989-01-01

227

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

228

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

229

High-energy accelerator for beams of heavy ions  

DOEpatents

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

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

1978-01-01

230

PHYSICS WITH AND PHYSICS OF COLLIDING ELECTRON BEAMS  

Microsoft Academic Search

When particle physics is a closed subject which has been condensed into a text book, the material will surely be organized by concepts and not according to what fact was learned on what accelerator. But short of that day facilities must be designed, planned, and developed, and experiments must be executed on one of a number of available accelerators; and

Claudio Pellegrini; Andrew M. Sessler

1969-01-01

231

Expanded studies of linear collider final focus systems at the Final Focus Test Beam  

SciTech Connect

In order to meet their luminosity goals, linear colliders operating in the center-of-mass energy range from 3,50 to 1,500 GeV will need to deliver beams which are as small as a few Manometers tall, with x:y aspect ratios as large as 100. The Final Focus Test Beam (FFTB) is a prototype for the final focus demanded by these colliders: its purpose is to provide demagnification equivalent to those in the future linear collider, which corresponds to a focused spot size in the FFTB of 1.7 microns (horizontal) by 60 manometers (vertical). In order to achieve the desired spot sizes, the FFTB beam optics must be tuned to eliminate aberrations and other errors, and to ensure that the optics conform to the desired final conditions and the measured initial conditions of the beam. Using a combination of incoming-beam diagnostics. beam-based local diagnostics, and global tuning algorithms, the FFTB beam size has been reduced to a stable final size of 1.7 microns by 70 manometers. In addition, the chromatic properties of the FFTB have been studied using two techniques and found to be acceptable. Descriptions of the hardware and techniques used in these studies are presented, along with results and suggestions for future research.

Tenenbaum, P.G.

1995-12-01

232

A laser-plasma accelerator producing monoenergetic electron beams  

Microsoft Academic Search

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

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

2004-01-01

233

Collider detector beam line test table: a structural analysis  

SciTech Connect

The apparatus which sweeps calorimeter and endwall modules through the beam during testing is called a beam line test table. Because of rather stringent requirements for the physical positioning of the modules an analysis is done here to determine the modifications to the current test table design which will minimize deflections of the table under load.

Leininger, M.B.

1983-12-23

234

Collider detector beam line test table: a structural analysis  

SciTech Connect

The apparatus which sweeps calorimeter and endwall modules through the beam during testing is called a beam line test table. Because of rather stringent requirements for the physical positioning of the modules an analysis is done here to determine the modifications to the current test table design which will minimize deflections of the table under load.

Leininger, M.B.

1983-12-01

235

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

236

Beam-Based Feedback System for the International Linear Collider  

NASA Astrophysics Data System (ADS)

The algorithms and computer codes for linac Feedback system were developed at SLAC during 1991-2004. The efficiency of that system have been demonstrated for the SLC, CLIC, TESLA and NLC projects. International Linear Collider (ILC) has its own features. Ground motion (GM) oscillations play a dominant role here. It forced to implement a new version of the Linac Feedback Simulation Code based on the previous developments. A set of benchmark tests and realistic simulations for the whole ILC structure have been performed. The effects of different GM models, BPM resolution, time intervals, initial misalignments, a dispersion-free steering (DFS), and a quad jitter have been studied.

Ivanov, Valentin

237

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

238

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

Microsoft Academic Search

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

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

2001-01-01

239

Beam tube vacuum in low field and high field very large hadron colliders  

Microsoft Academic Search

Bounds on the beam tube gas pressure and the required pumping speed are estimated for ~ 2 T low field (LF) and ~ 12 T high field (HF) 100 TeV center-of-mass hadron colliders. In both cases photodesorption by synchrotron radiation is the dominant source of gas. Assuming beam-gas scattering limited luminosity lifetime five times the IP scattering lifetime, the required

William C. Turner

1996-01-01

240

Synchrotron radiation induced gas desorption from a Prototype Large Hadron Collider beam screen at cryogenic temperatures  

Microsoft Academic Search

The performance of the vacuum system of the Large Hadron Collider will depend critically on the synchrotron radiation induced gas desorption and on the readsorption of molecules on the cold surfaces. The present design of the system is based on a so-called beam screen inserted in the 1.9 K cold bore of the magnets. Gas molecules desorbed will therefore readsorb

R. Calder; O. Gröbner; A. G. Mathewson; V. V. Anashin; A. Dranichnikov; O. B. Malyshev

1996-01-01

241

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

Microsoft Academic Search

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

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

2009-01-01

242

Computer Simulation of Crystal Extraction of Protons from a Large-Hadron-Collider Beam  

Microsoft Academic Search

The extraction of protons from the halo of the Large-Hadron-Collider beam by means of bent crystal channeling has been simulated by computer, making use of the simulation code catch tested earlier in a CERN-SPS crystal extraction experiment. The multipass extraction efficiency and the background produced with the aligned crystal have been investigated.

Valery Biryukov

1995-01-01

243

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

244

Target Material Irradiation Studies for High-Intensity Accelerator Beams  

SciTech Connect

This paper presents results of recent experimental studies focusing on the behavior of special materials and composites under irradiation conditions and their potential use as accelerator targets. The paper also discusses the approach and goals of on-going investigations on an expanded material matrix geared toward the neutrino superbeam and muon collider initiatives.

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

2005-08-16

245

High Energy Particle Colliders: Past 20 Years, Next 20 Years and Beyond.  

National Technical Information Service (NTIS)

Particle colliders for high energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the collider has progressed immensely, while the beam energy, luminosity, facility size and the cos...

V. D. Shiltsev

2012-01-01

246

Characteristics of an electron-beam rocket pellet accelerator  

SciTech Connect

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

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

1989-01-01

247

Novel Module for Plasma Wakefield Acceleration of a Positron Beam  

SciTech Connect

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

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

2006-11-27

248

Phase and amplitude considerations for the Two-Beam Accelerator  

SciTech Connect

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

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

1985-02-01

249

Polymeric flocculants processing by accelerated electron beams and microwave heating  

Microsoft Academic Search

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

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

2002-01-01

250

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

Microsoft Academic Search

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

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

1988-01-01

251

The production of accelerated radioactive ion beams  

SciTech Connect

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

Olsen, D.K.

1993-11-01

252

Future Hadron Super Colliders:. the Farthest Energy Frontier  

Microsoft Academic Search

Advances in superconducting materials and magnets, in accelerator physics, and in beam feedback, control and instrumentation systems allow us to consider the practical design of a proton collider with a discovery potential well beyond that of the Large Hadron Collider (LHC) currently being constructed at CERN. The ELOISATRON (ELN) (or Very Large Hadron Collider (VLHC)) represents what may well be

William A. Barletta

2004-01-01

253

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.

254

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.

255

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.

256

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

SciTech Connect

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

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

2009-01-01

257

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

258

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

259

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

260

Aspects of Stability Related to the Colliding Beam Fusion = Reactor  

Microsoft Academic Search

Recent experiments with TFTR, D-III-D and JET involving the injection and trapping of low density beams of high energy large orbit ions indicate that large orbit non-adiabatic ions slow down and diffuse classically in the presence of anomalous fluctuations and transport of adiabatic majority particles. Accordingly, we consider conceptual fusion reactors(N. Rostoker, M.W. Binderbauer and H.J. Monkhorst, Science) 278, 1419

Michl Binderbauer; Norman Rostoker; Hendrik Monkhorst

1998-01-01

261

Self-accelerating self-trapped optical beams.  

PubMed

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

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

2011-05-26

262

Protecting LHC components against radiation resulting from colliding beam interactions  

SciTech Connect

Beam-induced energy deposition in the LHC high luminosity interaction region (IR) components due to both pp collisions and beam loss in the IR vicinity is a significant challenge for the design of the high luminosity insertions. It was shown in our previous studies that a set of collimators in the machine and absorbers within the low-beta quadrupoles would reduce both the peak power density and total heat load to tolerable levels with a reasonable safety margin. In this paper the results of further optimization and comprehensive MARS calculations are briefly described for the updated IP1 and IP5 layouts and a baseline pp-collision source term. Power density, power dissipation, accumulated dose and residual dose rates are studied in the components of the inner triplets including their TAS absorbers, the TAN neutral beam absorbers, separation dipoles, and quadrupoles of the outer triplets and possible collimators there. It is shown that the optimized absorbers and collimators provide adequate protection of all the critical components.

Nikolai V. Mokhov and Igor L. Rakhno

2001-06-26

263

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

264

Degradation of multibunch luminosity in a linear collider due to cumulative beam breakup.  

National Technical Information Service (NTIS)

Beam-excited transverse wakes in accelerating radiofrequency structures will influence the transverse offsets of each bunch in a multibunch train, causing the projected emittance of the bunch train to grow. An analytic theory of this phenomenon that inclu...

C. L. Bohn M. J. Syphers D. Schulte

2001-01-01

265

Design of a 1-MV induction injector for the Relativistic Klystron Two-Beam Accelerator  

SciTech Connect

A Relativistic Klystron Two-Beam Accelerator (RK-TBA) is envisioned as a rf power source upgrade of the Next Linear Collider. Construction of a prototype, called the RTA, based on the RK-TBA concept has commenced at the Lawrence Berkeley National Laboratory. This prototype will be used to study physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. The first half of the injector, a 1 MeV, 1.2 kA, 300 ns induction electron gun, has been built and is presently being tested. The design of the injector cells and the pulsed power drive units are presented in this paper.

Anderson, D.E.; Eylon, S.; Lidia, S.; Reginato, L.; Vanecek, D.; Yu, S. [Lawrence Berkeley National Lab., CA (United States); Houck, T.; Westenskow, G.A. [Lawrence Livermore National Lab., CA (United States); Henestroza, E. [California Univ., Davis, CA (United States)

1997-05-01

266

Plasma accelerators  

SciTech Connect

In this paper we discuss plasma accelerators which might provide high gradient accelerating fields suitable for TeV linear colliders. In particular we discuss two types of plasma accelerators which have been proposed, the Plasma Beat Wave Accelerator and the Plasma Wake Field Accelerator. We show that the electric fields in the plasma for both schemes are very similar, and thus the dynamics of the driven beams are very similar. The differences appear in the parameters associated with the driving beams. In particular to obtain a given accelerating gradient, the Plasma Wake Field Accelerator has a higher efficiency and a lower total energy for the driving beam. Finally, we show for the Plasma Wake Field Accelerator that one can accelerate high quality low emittance beams and, in principle, obtain efficiencies and energy spreads comparable to those obtained with conventional techniques.

Ruth, R.D.; Chen, P.

1986-03-01

267

Multi-stage intense ion beam electrostatic accelerator for ICF  

SciTech Connect

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

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

1981-06-01

268

Estimates of the radioactivity produced in the proposed SSC (superconductivity super collider) beam absorbers  

SciTech Connect

This paper reviews in some detail personnel exposure rates which will be encountered when the time comes for the decommissioning of the Superconducting Super Collider beam dump absorbers. Discussed are estimates for the total radioactivity content of the graphite core and for residual absorbed dose rates at the surface of the core, the steel container, and the inner surface of the concrete shielding. 10 refs., 10 figs. (LSP)

Cossairt, J.D.

1987-11-01

269

Beam extraction from TeV accelerators using channeling in bent crystals  

SciTech Connect

Bent crystal channeling offers an interesting alternative for beam extraction from trans-GeV accelerators. Conventional extraction employs resonant beam blow-up coupled with electromagnetic beam deflecting channels. It is limited by the length of the available accelerator straight section. Channeling crystals require much less space. A five-step approach to applying crystal extraction in the Superconducting Super Collider (SSC) is discussed. Two steps, extraction from the 8 GeV Dubna Synchrophasotron and the 76 GeV Serpukhov accelerator, have occurred. The next possibility is extraction from a multi-hundred GeV superconducting accelerator. In the nineties the program could continue at UNK (3 TeV) and culminate at the TeV SSC. The possibilities and limitations of crystal extraction are reviewed. More information is needed on dechanneling in bent crystals including the effects of dislocations at TeV energies. Long, dislocation-free'' crystals are required. A more thorough understanding of the theory of crystal extraction is also desirable. 12 refs.

Carrigan, R.A. Jr.; Toohig, T.E.; Tsyganov, E.N. (Fermi National Accelerator Lab., Batavia, IL (USA); Superconducting Super Collider Lab., Dallas, TX (USA); Joint Inst. for Nuclear Research, Dubna (USSR))

1989-08-01

270

High energy electron beam processing experiments with induction accelerators  

Microsoft Academic Search

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

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

1995-01-01

271

Sterilization of Mail by Means of an Electron Beam Accelerator  

Microsoft Academic Search

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

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

2002-01-01

272

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

273

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

NASA Astrophysics Data System (ADS)

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

Hara, Toru; Togawa, Kazuaki; Tanaka, Hitoshi

2010-12-01

274

Study of a microwave power source for a two-beam accelerator  

SciTech Connect

A theoretical and experimental study of a microwave power source suitable for driving a linear e{sup +}e{sup {minus}} collider is reported. The power source is based on the Relativistic Klystron Two-Beam Accelerator (RK-TBA) concept, is driven by a 5-MeV, 1-kA induction accelerator electron beam, and operates at X-band frequencies. The development of a computer code to simulate the transverse beam dynamics of an intense relativistic electron beam transiting a system of microwave resonant structures is presented. This code is time dependent with self-consistent beam-cavity interactions and uses realistic beam parameters. Simulations performed with this code are compared with analytical theory and experiments. The concept of spacing resonant structures at distances equal to the betatron wavelength of the focusing system to suppress the growth of transverse instabilities is discussed. Simulations include energy spread over the beam to demonstrate the effect of Landau damping and establish the sensitivity of the betatron wavelength spacing scheme to errors in the focusing system. The design of the Reacceleration Experiment is described in detail and includes essentially all the issues related to a full scale RK-TBA microwave source. A total combined power from three output structures in excess of 170 MW with an amplitude stability of {+-}4% over a 25 ns pulse was achieved. The results of the experiment are compared to simulations used during the design phase to validate the various codes and methods used. The primary issue for the RK-TBA concept is identified as transverse beam instability associated with the excitation of higher order modes in the resonant structures used for extracting microwave power from the modulated beam. This work represents the first successful experimental demonstration of repeated cycles of microwave energy extraction from and reacceleration of a modulated beam.

Houck, T.L.

1994-08-15

275

Thermal Stress Analyses for an NLC Positron Target with a 3-mm Spot Radius Beam. Linear Collider Collaboration Tech Notes.  

National Technical Information Service (NTIS)

The power deposition of an incident electron beam in a tungsten-rhenium target and the resultant thermal shock stresses in the material have been modeled with a transient, dynamic, structural response finite element code. The Next Linear Collider electron...

W. Stein A. Sunwoo J. Sheppard V. Bharadwaj D. Schultz

2004-01-01

276

Low and Medium Energy Beam Acceleration in High Intensity Linacs  

Microsoft Academic Search

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

James Stovall

2004-01-01

277

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

278

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

279

Electron Beam Generation from Self-Modulated Laser Wakefileld Accelerator  

Microsoft Academic Search

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

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

2004-01-01

280

Sustained Acceleration of Over-dense Plasmas by Colliding Laser Pulses  

SciTech Connect

We review recent PIC simulation results which show that double-sided irradiation of a thin overdense plasma slab by ultra-intense laser pulses from both sides can lead to sustained comoving acceleration of surface electrons to energies much higher than the conventional ponderomotive limit. The acceleration stops only when the electrons drift transversely out of the laser beam. We show results of parameter studies based on this concept and discuss future laser experiments that can be used to test these computer results.

Liang, Edison [Rice University, Houston, TX 77005-1892 (United States)

2006-04-07

281

Beam collimation and machine detector interface at the International Linear Collider  

SciTech Connect

Synchrotron radiation, beam-gas scattering and beam halo interactions with collimators and other components in the ILC beam delivery system (BDS) would create fluxes of muons and other secondaries which could exceed the tolerable levels at a detector by a few orders of magnitude. It is shown that with a multi-stage collimation system, magnetized iron spoilers which fill the tunnel and a set of masks in the detector, one can hopefully meet the design goals. Results of modeling with the STRUCT and MARS15 codes of beam loss and energy deposition effects are presented in this paper. We focus on the collimation system and mask performance optimization, short- and long-term survivability of the critical components (spoilers, absorbers and magnets), dynamic heat loads and radiation levels in magnets and other components, and machine-related backgrounds in collider detectors.

Mokhov, N.V.; Drozhdin, A.I.; Kostin, M.A.; /Fermilab

2005-05-01

282

Fast ignition by a laser-accelerated deuteron beam  

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

283

Beam extraction from a Hall-type ion accelerator  

SciTech Connect

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

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

2008-02-15

284

Beam dynamics in the Advanced Test Accelerator (ATA)  

SciTech Connect

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

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

1983-09-28

285

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC  

Microsoft Academic Search

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

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

2009-01-01

286

Injection of high brightness H- beams into RFQ accelerators  

NASA Astrophysics Data System (ADS)

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

Reiser, M.

1991-05-01

287

The IFMIF-EVEDA accelerator beam dump design  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

288

600 kV modulator design for the SLAC Next Linear Collider Test Accelerator  

SciTech Connect

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 {mu}s, 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 {approx} 100 MW peak RF power. The design goals for the modulator, including those previously listed, are peak modulator pulse power of 340 MW operating at 120 Hz. A three-stage darlington pulse-forming network, which produces a >100 kV, 1.4 {mu}s pulse, is coupled to the klystron load through a 6:1 pulse transformer. Careful consideration of the transformer leakage inductance, klystron capacitance, system layout, and component choice is necessary to produce the very fast rise and fall times at 600 kV operating continuously at 120 Hz.

Harris, K.; de Lamare, J.; Nesterov, V.; Cassel, R.

1992-07-01

289

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

290

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

291

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

292

Particle-beam accelerators for radiotherapy and radioisotopes  

NASA Astrophysics Data System (ADS)

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

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

293

Beam Losses and Background Loads on Collider Detectors Due to Beam-Gas Interactions in the LHC  

SciTech Connect

With a fully-operational high-efficient collimation system in the LHC, nuclear interactions of circulating protons with residual gas in the machine beam pipe can be a major source of beam losses in the vicinity of the collider detectors, responsible for the machine-induced backgrounds. Realistic modeling of Coulomb scattering, elastic and inelastic interactions of 7-TeV protons with nuclei in the vacuum chamber of the cold and warm sections of the LHC ring--with an appropriate pressure profile--is performed with the STRUCT and MARS15 codes. Multi-turn tracking of the primary beams, propagation of secondaries through the lattice, their interception by the tertiary collimators TCT as well as properties of corresponding particle distributions at the CMS and ATLAS detectors are studied in great detail and results presented in this paper.

Drozhdin, A.I.; Mokhov, N.V.; Striganov, S.I.; /Fermilab

2009-04-01

294

Application of a sawtooth surface to accelerator beam chambers with low electron emission rate  

NASA Astrophysics Data System (ADS)

One of the latest problems in positron or proton accelerators is a single-beam instability due to an electron cloud around the beam. The instability, for an example, causes a beam size blow up of the positron beam and deteriorates the performance of the electron-positron collider. the seed of the electron cloud is the electrons emitted from the surface of the beam chamber, which consists of electrons due to the synchrotron radiation (photoelectrons) and sometimes those multiplied by the multipactoring. Suppressing the electron emission from the surface is, therefore, an essential way to cure the instability. Here a rough surface with a sawtooth structure (sawtooth surface) is proposed to reduce the electron emission from the surface of the beam chamber. A new rolling-tap method is developed for this study to make the sawtooth surface in a circular beam chamber with a length of several meters. The first experiment using a test chamber at a photon beam line of the KEK Photon Factory verifies its validity. The photoelectron emission from the sawtooth surface reduces by one order of magnitude compared to the usual smooth surface. In the second experiment under a bunched positron beam in the KEK B-Factory, however, the electron emission is comparable to that of a smooth surface and the behavior is quite different from the previous one. The reason is that the beam field excites the multipactoring of electrons and the decrease of the photoelectron emission by the sawtooth surface is wiped out. The sawtooth surface will be effective to reduce the electron emission under the situation with external magnetic fields or without strong beam fields where the electron multipactoring hardly occurs.

Suetsugu, Y.; Tsuchiya, M.; Nishidono, T.; Kato, N.; Satoh, N.; Endo, S.; Yokoyama, T.

2003-01-01

295

Neutrino physics at muon colliders  

SciTech Connect

An overview is given of the neutrino physics potential of future muon storage rings that use muon collider technology to produce, accelerate and store large currents of muons. After a general characterization of the neutrino beam and its interactions, some crude quantitative estimates are given for the physics performance of a muon ring neutrino experiment (MURINE) consisting of a high rate, high performance neutrino detector at a 250 GeV muon collider storage ring.

King, B.J.

1998-03-01

296

Double-decker femtosecond electron beam accelerator for pulse radiolysis  

NASA Astrophysics Data System (ADS)

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

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

2006-04-01

297

Controlled Electron Acceleration in a Plane Laser Beam  

NASA Astrophysics Data System (ADS)

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

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

2002-11-01

298

Beam breakup instabilities in high current electron beam racetrack induction accelerators  

SciTech Connect

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

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

1983-08-01

299

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

300

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

301

Accelerator Based Neutron Beams for Neutron Capture Therapy  

SciTech Connect

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

Yanch, Jacquelyn C.

2003-04-11

302

Beam tube vacuum in low field and high field very large hadron colliders  

SciTech Connect

Bounds on the beam tube gas pressure and the required pumping speed are estimated for {approximately} 2 T low field (LF) and - 12 T high field (HF) 100 TeV center-of-mass hadron colliders. In both cases photodesorption by synchrotron radiation is the dominant source of gas. Assuming beam-gas scattering limited luminosity lifetime five times the IP scattering lifetime, the required CO equivalent beam tube pressure is 0.25 ntorr for LF and 1.8 ntorr for HF, ambient room temperature equivalent. The CO equivalent pumping speeds required to achieve this pressure within a reasonable beam conditioning time (a few tenths of an operational year at design intensity) are estimated to be {approximately} 300 I/s-m for LF and - 40 I/s-m for HF. For the LF case with a superferric warm and a distributed NEG plus lumped ion or cryo pump system is considered. The size of antechamber needed, ID- 6 cm, requires that it be located outside the - 2 cm C-coil magnet gap. Lumped pumps for pumping CH{sub 4} need to be spaced at - 20 in intervals on the antechamber. For the HF case the likely beam tube temperature .is 15-20 K and cryopumping with a beam screen system is considered. The necessary pumping speed can be achieved with slots covering {approximately} 2 per cent of the beam screen surface.

Turner, W.C.

1996-10-01

303

Beam transport and monitoring for laser plasma accelerators  

SciTech Connect

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

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

2012-12-21

304

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

SciTech Connect

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. [Department of Energy Sciences, Tokyo Institute of Technology, Yokohama 226-8502 (Japan); Radiation Laboratory, RIKEN, Saitama 351-0198 (Japan); Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Kanesue, T. [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Tamura, J. [Department of Energy Sciences, Tokyo Institute of Technology, Yokohama 226-8502 (Japan); Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2010-02-15

305

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

306

Prototype microwave source for a relativistic klystron two-beam accelerator  

SciTech Connect

A test facility is established at Lawrence Berkeley National Laboratory (LBNL) to study RF power sources for linear colliders based on the Relativistic Klystron two-beam accelerator (RK-TBA) concept. A 24-m long prototype source, the RTA, will be constructed in this facility to study physics, engineering, and cost issues related to RK-TBA`s. The RTA will generate 200-ns 180-MW RF (11.4-GHz) pulses from each of eight output ports. The major components of the RTA include a 2.8-MeV 1.2-kA induction injector, transverse beam modulator, adiabatic compressor, and RF extraction section. The beam energy is increased to 4 MeV and the RF bunch length is shortened from 240{degree} to 110{degree} in the adiabatic compressor. The 8-m long extraction section includes 40 induction accelerator cells to maintain beam energy at an average 4 MeV, eight equally spaced RF output structures, and a ppm quadrupole focusing system. In this paper, the authors describe the RTA and present results of component testing and computer simulations.

Houck, T.; Deadrick, F.; Westenskow, G.A. [Lawrence Livermore National Lab., CA (United States); Giordano, G. [Univ. of Milano, Milan (Italy); Henestroza, E.; Lidia, S.; Reginato, L.; Vanecek, D.; Yu, S. [Lawrence Berkeley National Lab., CA (United States)

1996-06-01

307

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

308

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

309

Two-beam, Multi-mode Detuned Accelerating Structure  

SciTech Connect

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

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

2009-01-22

310

Production of an Accelerated Oxygen-14 Beam.  

National Technical Information Service (NTIS)

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

J. Powell J. P. Neil J. Cerny

2002-01-01

311

Development of a Compact Rotating-Wave Electron Beam Accelerator  

Microsoft Academic Search

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

Jose E. Velazco; Peter H. Ceperley

2003-01-01

312

Acceleration Test of Radioactive Nuclear Beam at INS  

NASA Astrophysics Data System (ADS)

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

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

1997-05-01

313

TRANSVERSE WAKEFIELD EFFECTS IN THE TWO-BEAM ACCELERATOR  

SciTech Connect

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

Selph, F.; Sessler, A.

1985-08-01

314

Monoenergetic Proton Beams Accelerated by a Radiation Pressure Driven Shock  

SciTech Connect

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

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

2011-11-01

315

Laser-driven shock acceleration of monoenergetic ion beams.  

PubMed

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

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

2012-11-20

316

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

317

POLARIZED PROTON ACCELERATION IN AGS AND RHIC.  

SciTech Connect

As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species including polarized proton beams. The acceleration of polarized beams in both the injector and the collider rings is complicated by numerous depolarizing spin resonances. Partial and full Siberian snakes have made it possible to overcome the depolarization and beam polarizations of up to 65% have been reached at 100 GeV in RHIC.

ROSER,T.

2007-09-10

318

Polarized Proton Acceleration in AGS and RHIC  

SciTech Connect

As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species including polarized proton beams. The acceleration of polarized beams in both the injector and the collider rings is complicated by numerous depolarizing spin resonances. Partial and full Siberian snakes have made it possible to overcome the depolarization and beam polarizations of up to 65% have been reached at 100 GeV in RHIC.

Roser, Thomas [Brookhaven National Laboratory, Upton, New York 11793-5000 (United States)

2008-02-06

319

Gamma-ray generation using laser-accelerated electron beam  

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

320

Plasma wakefield acceleration of an intense positron beam  

NASA Astrophysics Data System (ADS)

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

Blue, Brent Edward

321

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 {micro}{sup +}{micro}{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.

Palmer, R.B. [Brookhaven National Lab., Upton, NY (United States)]|[Stanford Linear Accelerator Center, Menlo Park, CA (United States); Sessler, A. [Lawrence Berkeley Lab., CA (United States); Skrinsky, A. [BINP, RU-630090 Novosibirsk (Russian Federation)] [and others

1996-01-01

322

Coherent beam-beam effects observation and mitigation at the RHIC collider  

SciTech Connect

In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

White S.; Fischer, W.; Luo, Y.

2012-05-20

323

Study of Electron-Proton Beam-Beam Interaction in eRHIC.  

National Technical Information Service (NTIS)

Beam-beam effects present one of major factors limiting the luminosity of colliders. In the linac-ring option of eRHIC design, an electron beam accelerated in a superconducting energy recovery linac collides with a proton beam circulating in the RHIC ring...

C. Montag E. Pozdeyev V. Ptitsyn V. N. Litvinenko Y. Hao

2007-01-01

324

Photon desorption measurements of copper and copper plated beam tubes for the SSCL 20 TeV proton collider  

Microsoft Academic Search

Relativistic protons circulating in the SSCL 20 TeV collider emit synchrotron radiation (10[sup 16] photons\\/m\\/s, [ital E][sub crit]=284 eV). This radiation will photodesorb gases from the walls of the beam tube. The 4.2 K superconducting magnet bore tubes will act as very long distributed pumps. Build up of cryosorbed gases could severely limit collider operation and may require a bore

C. L. Foerster; C. Lanni; I. Maslennikov; W. Turner

1994-01-01

325

Production and acceleration of ion beams by laser ablation  

SciTech Connect

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

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

2012-02-15

326

Applications of laser-accelerated particle beams for radiation therapy  

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

327

Experiment and Simulations with Nearly Equal Horizontal and Vertical Focusing Functions: Single and Colliding Beam Results from the Cornell Electron Storage Ring  

NASA Astrophysics Data System (ADS)

For colliding beam particle accelerators, the dynamics of the beam beam interaction are one limit on the luminosity or event rate. Simulations of the beam beam interaction have suggested that round beams (equal horizontal and vertical emittances and beta ^{*}) could produce saturated tune shifts of about 0.100, much larger than those predicted for flat beams (horizontal emittance and beta ^{*} much larger than the vertical). This experiment was designed to test round beams and had a single interaction point at the North Interaction Region or NIP, with nearly zero horizontal dispersion and about 25 cm beta^{*} 's. In early 1990 we used about 140 hours of machine time. Beginning with flat beams (horizontal emittance much larger than the vertical emittance), we achieved saturated vertical tune shift parameters of about 0.045, very high for CESR at the time, but much smaller than the 0.080 predicted by the simulations for this case. During this flat beam work, we realized we had several experimental problems and halted the experiment without attempting the round beam work. Our separation scheme for the South Interaction Region or SIP produced different horizontal emittances and damping times for the electrons and positrons and so we reduced the separation in the SIP until we were concerned about the near miss beam crossing there. Also later analysis of orbit measurements showed small, but important, horizontal separations at the NIP. We've used a beam beam simulation to understand the effects that each of these problems has on the beam beam dynamics. Also using both an analytic formalism for the effects of resonances on single particles and several diagnostics to look at the simulation results for single particles, we've developed some understanding of why the simulations give the results they do and which resonances are important. We believe "dirt" effects, rather than fundamental limitations, set our experimental tune shift limit and that the nearly equal beta^{ *} did not play an essential role in our beam beam dynamics. Although originally intended to study round beams, this has become a study of how "dirt" effects in experiments can set the beam beam limits.

Bagley, Peter Paul

1995-01-01

328

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

329

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

330

Revealing the large extra dimension effective interaction at an e+e- collider with polarized beams  

NASA Astrophysics Data System (ADS)

Several types of new physics scenarios are represented by contactlike effective interactions. An example is the exchange of nonstandard quanta of very large mass scales, beyond the kinematical limit for direct production set by the available collider energy. This kind of interactions can be revealed only through deviations of observables from the standard model predictions. If such deviations were observed, the relevant source should be identified among the possible models that could explain them. Here, we assess the expected “identification reach” on the ADD model of gravity in large compactified extra dimensions, against the compositeness-inspired four-fermion contact interaction. As basic observables we take the differential cross sections for fermion-pair production at a 0.5 1 TeV electron-positron linear collider with both beams longitudinally polarized. For the four-fermion contact interaction, we assume a general linear combination of the individual models with definite chiralities, with arbitrary coupling constants. In this sense, the estimated identification reach on the ADD model can be considered as “model independent.” In the analysis, we give estimates also for the expected “discovery reaches” on the various scenarios. We emphasize the substantial role of beams polarization in enhancing the sensitivity to the contactlike interactions under consideration.

Pankov, A. A.; Tsytrinov, A. V.; Paver, N.

2007-05-01

331

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

332

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

333

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

334

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

National Technical Information Service (NTIS)

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

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

1993-01-01

335

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

National Technical Information Service (NTIS)

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

W. T. Diamond R. Pico

1989-01-01

336

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

337

Reactive accelerated cluster erosion (RACE) by ionized cluster beams  

NASA Astrophysics Data System (ADS)

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

Gspann, J.

1996-05-01

338

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

339

Transverse beam instability in a 50 /GeV×50 GeV muon-collider ring  

NASA Astrophysics Data System (ADS)

The transverse beam instability due to a broad-band impedance in a 50GeV×50GeV muon-collider ring is numerically investigated. It is shown that the transverse beam size is increased by a factor of five when the impedance, Z||/n, is 1.7?. The transverse instability is shown to be cured by introducing tune spreads, such as BNS damping, chromaticity, amplitude-dependent tune shift, and beam-beam interaction. It is shown that any one of these tune spreads limits the growth of the beam size to less than /20%.

Kim, E.-S.; Yoon, M.

2001-09-01

340

Beam physics developments for a rare isotope accelerator  

NASA Astrophysics Data System (ADS)

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

Portillo, Mauricio

341

The status of the SLAC Linear Collider and of the Mark II detector  

Microsoft Academic Search

At SLAC we are currently involved in the exciting challenge of commissioning the first example of a new type of colliding beam accelerator, the SLAC Linear Collider, or SLC. The goals of the SLC are two-fold. It will explore the concept of linear colliders, and it will allow the study of physics on the Z° resonance. It accomplishes these goals

1987-01-01

342

Neutral beam injection with an improved accelerator for LHD  

SciTech Connect

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

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

2008-02-15

343

Luminosity limitations for Electron-Ion Collider  

SciTech Connect

The major limitations on reaching the maximum luminosity for an electron ion collider are discussed in application to the ring-ring and linac-ring colliders. It is shown that with intensive electron cooling the luminosity of 10{sup 33} cm{sup -2} s{sup -1} is feasible for both schemes for the center-of-mass collider energy above approximately 15 GeV. Each scheme has its own pros and cons. The ring-ring collider is better supported by the current accelerator technology while the linac-ring collider suggests unique features for spin manipulations of the electron beam. The article addresses a general approach to a choice of collider scheme and parameters leaving details for other conference publications dedicated to particular aspects of the ring-ring and linac-ring colliders.

Valeri Lebedev

2000-09-01

344

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

345

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

346

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

347

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

348

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

PubMed

The advent of high-intensity-pulsed laser technology enables the generation of extreme states of matter under conditions that are far from thermal equilibrium. This in turn could enable different approaches to generating energy from nuclear fusion. Relaxing the equilibrium requirement could widen the range of isotopes used in fusion fuels permitting cleaner and less hazardous reactions that do not produce high-energy neutrons. Here we propose and implement a means to drive fusion reactions between protons and boron-11 nuclei by colliding a laser-accelerated proton beam with a laser-generated boron plasma. We report proton-boron reaction rates that are orders of magnitude higher than those reported previously. Beyond fusion, our approach demonstrates a new means for exploring low-energy nuclear reactions such as those that occur in astrophysical plasmas and related environments. PMID:24104859

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

2013-01-01

349

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

350

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC  

SciTech Connect

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

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

2009-05-04

351

NOTE: Blood irradiation with accelerator produced electron beams  

NASA Astrophysics Data System (ADS)

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

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

2000-11-01

352

A large distributed digital camera system for accelerator beam diagnostics  

SciTech Connect

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

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

2005-07-15

353

A large distributed digital camera system for accelerator beam diagnostics  

NASA Astrophysics Data System (ADS)

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

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

2005-07-01

354

Ultralow emittance electron beams from a laser-wakefield accelerator  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

355

Quasimonoenergetic electron beams from laser wakefield acceleration in pure nitrogen  

SciTech Connect

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

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

2012-02-13

356

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

357

Reliability of Beam Loss Monitors System for the Large Hadron Collider  

NASA Astrophysics Data System (ADS)

The employment of superconducting magnets in high energy colliders opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particle losses, while at medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data have been processed by reliability software (Isograph). The analysis ranges from the components data to the system configuration.

Guaglio, G.; Dehning, B.; Santoni, C.

2004-11-01

358

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

359

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

360

Reliability of Beam Loss Monitor Systems for the Large Hadron Collider  

NASA Astrophysics Data System (ADS)

The increase of beam energy and beam intensity, together with the use of super conducting magnets, opens new failure scenarios and brings new criticalities for the whole accelerator protection system. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system, and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses at 7 TeV and assisted by the Fast Beam Current Decay Monitors at 450 GeV. At medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data has been processed by reliability software (Isograph). The analysis spaces from the components data to the system configuration.

Guaglio, G.; Dehning, B.; Santoni, C.

2005-06-01

361

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

SciTech Connect

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 Company. At this same time, a major new scientific facility, the Relativistic Heavy Ion Collider (RHIC), was nearing the end of construction and readying for commissioning. Although environmental considerations had been incorporated into the design of the facility; some interested parties were skeptical that this new facility would not cause significant environmental impacts. RHIC management recognized that the future of its operation was dependent on preventing pollution and allaying concerns of its stakeholders. Although never done at a DOE National Laboratory before Brookhaven Science Associates, the new management firm, committed to implementing an Environmental Management System (EMS) and RHIC managers volunteered to deploy it within their facility on an extremely aggressive schedule. Several of these IS0 requirements contribute directly to preventing pollution, an area where particular emphasis was placed. This paper describes how Brookhaven used the following key IS0 14001 elements to institutionalize Pollution Prevention concepts: Environmental Policy, Aspects, Objectives and Targets, Environmental Management Program, Structure and Responsibility, Operational Controls, Training, and Management Review. In addition, examples of implementation at the RHIC Project illustrate how BNL's premiere facility was able to demonstrate to interested parties that care had been taken to implement technological and administrative controls to minimize environmental impacts, while at the same time reduce the applicability of regulatory requirements to their operations.

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

2001-06-01

362

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

Microsoft Academic Search

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

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

1980-01-01

363

Microbunching and Beam Break Up in DUV FEL Accelerator  

SciTech Connect

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

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

2008-03-17

364

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

365

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

366

Bipolar pulse generator for intense pulsed ion beam accelerator  

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

367

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

368

Plasma Astrophysics in the Laboratory with Accelerator Beams  

Microsoft Academic Search

An ultra-relativistic electron\\/positron or ``fireball'' beam interacting with a laboratory plasma is subject to the current filamentation instability (CFI). In the near future, ultra-short (<100fs), ultra-relativistic (25GeV) electron and positron bunches will become available at the SLAC FACET facility. These bunches are accelerated one half period apart and overlapped in space and time near the final focal point. With an

P. Muggli; S. Martins; L. Silva

2010-01-01

369

Accelerated partial breast irradiation using proton beams: Initial dosimetric experience  

Microsoft Academic Search

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

Alphonse G.. Taghian; Kevin R. Kozak; Angela Katz; Judith C. Adams; Hsiao-Ming Lu; Simon N. Powell; Thomas F. DeLaney

2006-01-01

370

Modeling of beam-ionized sources for plasma accelerators  

Microsoft Academic Search

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

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

2003-01-01

371

Isochoric heating with laser-accelerated proton beams  

NASA Astrophysics Data System (ADS)

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

Carrié, M.; Combis, P.; Lefebvre, E.

2010-12-01

372

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

373

Far Future Colliders and Required R&D Program  

SciTech Connect

Particle colliders for high energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the collider has progressed immensely, while the beam energy, luminosity, facility size and the cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but its pace of progress has greatly slowed down. In this paper we very briefly review the R&D toward near future colliders and make an attempt to look beyond the current horizon and outline the changes in the paradigm required for the next breakthroughs.

Shiltsev, V.; /Fermilab

2012-06-01

374

Negative hydrogen ion source research and beam parameters for accelerators  

SciTech Connect

H{sup -} beams are useful for multi-turn charge-exchange stripping injection into circular accelerators. Studies on a modified ion source for this purpose are presented. This paper includes some theory about a H{sup -} magnetron discharge, ion-electron emission, emittance and problems linked with emittance measurement and calculations. Investigated parameters of the emittance probe for optimal performance give a screen voltage of 150 V and a probe step of about 5 mil. Normalized 90% emittance obtained for this H{sup -} source is 0.22 {pi} mm-mr, for an extraction voltage of 18 kV at a beam energy of 30 keV and a beam current of 11 mA.

Zolkin, Timofey V.; /Fermilab

2006-09-01

375

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

376

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

377

Wakefield suppression in high gradient linacs for lepton linear colliders  

NASA Astrophysics Data System (ADS)

The transverse wakefield excited by multiple bunches in ultrarelativistic charged particle beams in a linear collider must be adequately damped in order to preserve the luminosity of the colliding beams and to prevent a beam breakup instability developing. A review of the means of achieving this wakefield suppression is discussed in detail for normal conducting linacs utilized for linear colliders. In particular, the features of a damped and detuned series of structures are described and compared to other methods. A conspectus of experimental results along with theoretical predictions for this series of accelerating structures developed for the next-linear-collider/global-linear-collider is presented together with the prospects for wakefield suppression for the compact linear collider.

Jones, Roger M.

2009-10-01

378

Simulation of the Beam-Ion Instability in the Electron Damping Ring of the International Linear Collider  

SciTech Connect

Ion induced beam instability is one critical issue for the electron damping ring of the International Linear Collider (ILC) due to its ultra small emittance of 2pm. Bunch train filling pattern is proposed to mitigate the instability and bunch-by-bunch feedback is applied to suppress it. Multibunch train fill pattern is introduced in the electron beam to reduce the number of trapped ions. Our study shows that the ion effects can be significantly mitigated by using multiple gaps. However, the beam can still suffer from the beam-ion instability driven by the accumulated ions that cannot escape from the beam during the gaps. The effects of beam fill pattern, emittance, vacuum and various damping mechanism are studied using self-consistent program, which includes the optics of the ring.

Wang, L.; Cai, Y.; Raubenheimer, T.; /SLAC

2007-07-06

379

Technical challenge of future linear colliders  

SciTech Connect

The next generation of high energy e/sup +/e/sup -/ colliders is likely to be built with colliding linear accelerators. A lot of research and development is needed before such a machine can be practically built. Some of the problems and recent progress made toward their solution are described here. Quantum corrections to beamstrahlung, the production of low emittance beams and strong focusing techniques are covered.

Himel, T.

1986-05-01

380

Plasma Astrophysics in the Laboratory with Accelerator Beams  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

381

Relativistic klystron research for two-beam accelerators  

SciTech Connect

We have tested a high-power 11.4-GHz rf generator which consists of a 5.7-GHz transverse modulating system and two 11.4-GHz traveling-wave output structures. The device was designed to generate 500 MW of pulsed rf power when driven by a 1-kA, 3-MeV induction accelerator beam. Transverse beam instability due to rf coupling between the two output structures has limited the width of the rf output pulse for currents above 600 amperes. Short rf pulses of total output power of up to 420 MW have been produced. Using a single output structure, rf output pulses with stable phase (< {plus_minus} 2{degree}) and amplitude (< {plus_minus} 2%) have been achieved for widths comparable to the beam width. We have modified and tested an output structure to decrease the growth of fields causing transverse instabilities. During the next year our experimental program will include both studies of rf power extraction and reacceleration of modulated electron beams. In support of reacceleration experiments, we are developing a time dependent computer code for the simulation of transverse instabilities due to dipole modes in the rf structures, and are upgrading the induction beam to 5 MeV.

Houck, T.L.; Rogers, D.; Ryne, R.D.; Westenskow, G.A.; Yu, S.S.

1992-01-01

382

Relativistic klystron research for two-beam accelerators  

SciTech Connect

We have tested a high-power 11.4-GHz rf generator which consists of a 5.7-GHz transverse modulating system and two 11.4-GHz traveling-wave output structures. The device was designed to generate 500 MW of pulsed rf power when driven by a 1-kA, 3-MeV induction accelerator beam. Transverse beam instability due to rf coupling between the two output structures has limited the width of the rf output pulse for currents above 600 amperes. Short rf pulses of total output power of up to 420 MW have been produced. Using a single output structure, rf output pulses with stable phase (< {plus minus} 2{degree}) and amplitude (< {plus minus} 2%) have been achieved for widths comparable to the beam width. We have modified and tested an output structure to decrease the growth of fields causing transverse instabilities. During the next year our experimental program will include both studies of rf power extraction and reacceleration of modulated electron beams. In support of reacceleration experiments, we are developing a time dependent computer code for the simulation of transverse instabilities due to dipole modes in the rf structures, and are upgrading the induction beam to 5 MeV.

Houck, T.L.; Rogers, D.; Ryne, R.D.; Westenskow, G.A.; Yu, S.S.

1992-01-01

383

Observation and Characterization of Coherent Optical Radiation and Microbunching Instability in the SLAC Next Linear Collider Test Accelerator  

SciTech Connect

The NLC Test Accelerator (NLCTA) at SLAC is currently configured for a proof-of-principle echo-enabled harmonic generation (EEHG) experiment using an 120 MeV beam. During commissioning, unexpected coherent optical undulator radiation (CUR) and coherent optical transition radiation (COTR) was observed when beam is accelerated off-crest and compressed after the chicanes. The CUR and COTR is likely due to a microbunching instability where the initial small ripples in cathode drive laser is compressed and amplified. In this paper we present the observation and characterization of the CUR, COTR and microbunching instability at NLCTA.

Weathersby, S.; Dunning, M.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Xiang, D.; /SLAC

2011-06-02

384

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

385

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

386

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

Microsoft Academic Search

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

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

1999-01-01

387

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

Microsoft Academic Search

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

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

1999-01-01

388

ACCELERATOR PHYSICS MODEL OF EXPECTED BEAM LOSS ALONG THE SNS ACCELERATOR FACILITY DURING NORMAL OPERATION.  

SciTech Connect

The most demanding requirement in the design of the SNS accelerator chain is to keep the accelerator complex under hands-on maintenance. This requirement implies a hard limit for residual radiation below 100 mrem/hr at one feet from the vacuum pipe and four hours after shutdown for hundred days of normal operation. It has been shown by measurements as well as simulation [l] that this limit corresponds to 1-2 Watts/meter average beam losses. This loss level is achievable all around the machine except in specific areas where remote handling will be necessary. These areas have been identified and correspond to collimation sections and dumps where a larger amount of controlled beam loss is foreseen. Even if the average level of loss is kept under 1 W/m, there are circumstances under which transient losses occur in the machine. The prompt radiation or potential damage in the accelerator components can not be deduced from an average beam loss of 1 W/m. At the same time, controlled loss areas require a dedicated study to clarify the magnitude and distribution of the beam loss. From the front end to the target, we have estimated the most probable locations for transient losses and given an estimate of their magnitude and frequency. This information is essential to calculate the necessary shielding or determine the safety procedures during machine operation. Losses in controlled areas, and the cleaning systems are the subject of Section 2. The inefficiency of each system will be taken into account for the discussion on Section 3 where n controlled loss is estimated. Section 4 summarizes our findings and presents a global view of the losses along the accelerator chain.

CATALAN - LASHERAS,N.; COUSINEAU,S.; GALAMBOS,J.; HOLTKAMP,N.; RAPARIA,D.; SHAFER,R.; STAPLES,J.; STOVALL,J.; TANKE,E.; WANGLER,T.; WEI,J.

2002-06-03

389

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

390

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

391

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

392

ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES.  

SciTech Connect

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

ROSER,T.AHRENS,L.BAI,M.ET AL.

2004-07-05

393

ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES.  

SciTech Connect

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

ROSER,T.; AHRENS,L.; BAI,M.; COURANT,E.; GLENN,J.W.; GUPTA,R.C.; HUANG,H.; LUCCIO,A.U.; MACKAY,W.W.; TSOUPAS,N.; WILLEN,E.; OKAMURA,M.; TAKANO,J.

2004-10-10

394

Acceleration of Polarized Beams Using Multiple Strong Partial Siberian Snakes  

NASA Astrophysics Data System (ADS)

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization, but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake, both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical super-conducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

Roser, T.; Ahrens, L. A.; Bai, M.; Courant, E. D.; Glenn, J. W.; Gupta, R. C.; Huang, H.; Luccio, A. U.; Mackay, W. W.; Tsoupas, N.; Willen, E.; Okamura, M.; Takano, J.

2005-08-01

395

Superconducting super collider 5T dipole magnet cryogenic design  

SciTech Connect

Proposed colliding beam particle accelerators for high energy physics research will employ superconducting accelerator rings. The rings' superconducting magnet systems must provide the required magnetic function, have low refrigeration load, operate with very high reliability and be manufacturable at a low cost. The cryogenic aspects of a conceptual design for a 5T field, 5cm aperture, 12m long superconducting dipole magnet suitable for a 20 TeV proton-proton collider are presented.

Niemann, R.C.; Carson, J.A.; Edwards, H.T.; Engler, H.N.; Gonczy, J.D.; Hanft, R.W.; Lundy, R.A.; Mantsch, P.M.; McInturff, A.D.; Nicol, T.H.; Powers, R.J.

1985-03-01

396

Electron beam dynamics in the DARHT-II linear induction accelerator  

SciTech Connect

The DARHT-II linear induction accelerator (LIA) accelerates a 2-kA electron beam to more than 17 MeV. The beam pulse has a greater than 1.5-microsecond flattop region over which the electron kinetic energy is constant to within 1%. The beam dynamics are diagnosed with 21 beam-position monitors located throughout the injector, accelerator, and after the accelerator exit, where we also have beam imaging diagnostics. We discuss the tuning of the injector and accelerator, and present data for the resulting beam dynamics. We discuss the tuning procedures and other methods used to minimize beam motion, which is undesirable for its application as a bremsstrahlung source for multi-pulse radiography of exlosively driven hydrodynamic experiments. We also present beam stability measurements, which we relate to previous stability experiments at lower current and energy.

Ekdahl, Carl A [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; Mccuistian, Brian T [Los Alamos National Laboratory; Montoya, Nicholas A [Los Alamos National Laboratory; Nath, Subrata [Los Alamos National Laboratory; Nielsen, Kurt [Los Alamos National Laboratory; Oro, David [Los Alamos National Laboratory; Prichard, Benjamin [Los Alamos National Laboratory; Rowton, Lawrence [Los Alamos National Laboratory; Sanchez, Manolito [Los Alamos National Laboratory; Scarpetti, Raymond [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 [NSTEC/STL; Williams, John [Los Alamos National Laboratory; Genoni, Thomas [VOSS; Hughes, Thomas [VOSS; Toma, Carsten [VOSS

2008-01-01

397

The development of colliders  

SciTech Connect

Don Kerst, Gersh Budker, and Bruno Touschek were the individuals, and the motivating force, which brought about the development of colliders, while the laboratories at which it happened were Stanford, MURA, the Cambridge Electron Accelerator, Orsay, Frascati, CERN, and Novosibirsk. These laboratories supported, during many years, this rather speculative activity. Of course, many hundreds of physicists contributed to the development of colliders but the men who started it, set it in the right direction, and forcefully made it happen, were Don, Gersh, and Bruno. Don was instrumental in the development of proton-proton colliders, while Bruno and Gersh spearheaded the development of electron-positron colliders. In this brief review of the history, I will sketch the development of the concepts, the experiments, and the technological developments which made possible the development of colliders. It may look as if the emphasis is on theoretical concepts, but that is really not the case, for in this field -- the physics of beams -- the theory and experiment go hand in hand; theoretical understanding and advances are almost always motivated by the need to explain experimental results or the desire to construct better experimental devices.

Sessler, A.M.

1993-02-01

398

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

399

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

Microsoft Academic Search

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

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

1995-01-01

400

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

2009-04-27

401

Cold beam tube photodesorption and related experiments for the Superconducting Super Collider Laboratory 20 TeV proton collider  

SciTech Connect

The first photodesorption experiments have been completed on the VEPP2M storage ring at the Budker Institute of Nuclear Physics (BINP). Additional photodesorption experiments are underway at BINP and are being planned for a beamline at the UV ring of the Brookhaven National Laboratory National Synchrotron Light Source (BNL NSLS). Related experiments at BNL measuring molecular sticking coefficients and at the State University of New York-Albany (SUNY-Albany) measuring the depth profile of hydrogen on beam tube surfaces are also beginning to yield data. New ideas for directly measuring molecular density inside a cryosorbing beam tube are under development---neutralization of H[sup [minus

Anashin, V.V.; Derevyankin, G.; Dudnikov, V.G.; Malyshev, O.B.; Osipov, V.N. (Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)); Foerster, C.L.; Jacobsen, F.M.; Ruckman, M.W.; Strongin, M. (Brookhaven National Laboratory, Upton, New York 11973 (United States)); Kersevan, R.; Maslennikov, I.L.; Turner, W.C. (Superconducting Super Collider Laboratory, Dallas, Texas 75237 (United States)); Lanford, W.A. (State University of New York-Albany, Albany, New York 12222 (United States))

1994-07-01

402

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

SciTech Connect

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

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

2012-01-01

403

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

404

An epithermal neutron beam from the MURR and from an accelerator source compared to the beam at the BMRR  

SciTech Connect

An ideal neutron beam for BNCT is a beam of epithermal neutrons, forward directed, and free of gamma rays and thermal and fast neutrons. Three neutron beams were evaluated, and compared: (1) the operating Brookhaven Medical Research Reactor (BMRR) epithermal beam, (2) the designed Missouri University Research Reactor (MURR) epithermal beam, and (3) the accelerator-based epithermal neutron beam designed by Wu. These neutron beams were compared with respect to the neutron spectra, neutron and gamma fluxes and doses, and beam directionality. The epithermal neutron beams were inter-compared for different beam parameters in air at the irradiation point. The BMRR beam has the highest neutron plus gamma doses per epithermal neutron among these neutron beams but is satisfactory for patient trials by BNCT at the present time. The RBE dose delivered to the normal brain reaches the tolerance dose limit before the skin RBE dose reaches its limit, so the skin dose can be controlled under the limit. Generally speaking, a treatment can be completed in 54 minutes using the BMRR beam for irradiation at a full-power operation of the reactor. The MURR beam has better beam parameters, including lower neutron and gamma doses per epithermal neutron, higher in intensity, and also directed. The irradiation time could be 5 minutes to complete a treatment. The accelerator-based neutron beam which has shown promising beam parameters similar to the BMRR beam could be a choice in hospitals. However, a complete system at the required power has not yet been demonstrated.

Liu, H.B.; Brugger, R.M.

1992-01-01

405

An epithermal neutron beam from the MURR and from an accelerator source compared to the beam at the BMRR  

SciTech Connect

An ideal neutron beam for BNCT is a beam of epithermal neutrons, forward directed, and free of gamma rays and thermal and fast neutrons. Three neutron beams were evaluated, and compared: (1) the operating Brookhaven Medical Research Reactor (BMRR) epithermal beam, (2) the designed Missouri University Research Reactor (MURR) epithermal beam, and (3) the accelerator-based epithermal neutron beam designed by Wu. These neutron beams were compared with respect to the neutron spectra, neutron and gamma fluxes and doses, and beam directionality. The epithermal neutron beams were inter-compared for different beam parameters in air at the irradiation point. The BMRR beam has the highest neutron plus gamma doses per epithermal neutron among these neutron beams but is satisfactory for patient trials by BNCT at the present time. The RBE dose delivered to the normal brain reaches the tolerance dose limit before the skin RBE dose reaches its limit, so the skin dose can be controlled under the limit. Generally speaking, a treatment can be completed in 54 minutes using the BMRR beam for irradiation at a full-power operation of the reactor. The MURR beam has better beam parameters, including lower neutron and gamma doses per epithermal neutron, higher in intensity, and also directed. The irradiation time could be 5 minutes to complete a treatment. The accelerator-based neutron beam which has shown promising beam parameters similar to the BMRR beam could be a choice in hospitals. However, a complete system at the required power has not yet been demonstrated.

Liu, H.B.; Brugger, R.M.

1992-12-31

406

Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data  

SciTech Connect

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

Rubel, Oliver; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Wu, Kesheng; Prabhat,; Weber, Gunther H.; Ushizima, Daniela M.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

2009-10-19

407

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

National Technical Information Service (NTIS)

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

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

1976-01-01

408

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

National Technical Information Service (NTIS)

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

S. A. Dupree

1982-01-01

409

The program in muon and neutrino physics: Superbeams, cold muon beams, neutrino factory and the muon collider  

SciTech Connect

The concept of a Muon Collider was first proposed by Budker [10] and by Skrinsky [11] in the 60s and early 70s. However, there was little substance to the concept until the idea of ionization cooling was developed by Skrinsky and Parkhomchuk [12]. The ionization cooling approach was expanded by Neufer [13] and then by Palmer [14], whose work led to the formation of the Neutrino Factory and Muon Collider Collaboration (MC) [3] in 1995. The concept of a neutrino source based on a pion storage ring was originally considered by Koshkarev [18]. However, the intensity of the muons created within the ring from pion decay was too low to provide a useful neutrino source. The Muon Collider concept provided a way to produce a very intense muon source. The physics potential of neutrino beams produced by muon storage rings was investigated by Geer in 1997 at a Fermilab workshop [19, 20] where it became evident that the neutrino beams produced by muon storage rings needed for the muon collider were exciting on their own merit. The neutrino factory concept quickly captured the imagination of the particle physics community, driven in large part by the exciting atmospheric neutrino deficit results from the SuperKamiokande experiment. As a result, the MC realized that a Neutrino Factory could be an important first step toward a Muon Collider and the physics that could be addressed by a Neutrino Factory was interesting in its own right. With this in mind, the MC has shifted its primary emphasis toward the issues relevant to a Neutrino Factory. There is also considerable international activity on Neutrino Factories, with international conferences held at Lyon in 1999, Monterey in 2000 [21], Tsukuba in 2001 [22], and another planned for London in 2002.

R. Raja et al.

2001-08-08

410

The development of an annular-beam, high power free-electron maser for future linear colliders  

SciTech Connect

Work is under way to develop a 17 GHz free electron maser (FEM) for producing a 500 MW output pulse with a phase stability appropriate for linear collider applications. We plan to use a 500 keV, 5 kV, 6 cm diameter annular electron beam to excite a TM{sub 02} mode Raman FEM amplifier in a corrugated cylindrical waveguide. The annular beam will run close to the interaction device walls to reduce the power density in the fields, and to greatly reduce the kinetic energy loss caused by beam potential depression associated with the space charge which is a significant advantage in comparison with conventional solid beam microwave tubes at the same beam current. A key advantage of the annular beam is that the reduced plasma wave number can be tuned to achieve phase stability for an arbitrary correlation on interaction strength with beam velocity. It should be noted that this technique for improving phase stability of an EM in not possible with a solid beam klystron. The annular beam FEM provides the opportunity to extend the output power of sources in the 17 GHz regime by well over an order of magnitude with enhanced phase stability. The design and experimental status are discussed.

Fazio, M.V.; Carlsten, B.E.; Earley, L.M.; Fortgang, C.M.; Haddock, P.C.; Haynes, W.B.

1996-09-01

411

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

412

Perspectives on large linear colliders  

SciTech Connect

Three main items in the design of large linear colliders are presented. The first is the interrelation of energy and luminosity requirements. These two items impose severe constraints on the accelerator builder who must design a machine to meet the needs of experimentl high energy physics rather than designing a machine for its own sake. An introduction is also given for linear collider design, concentrating on what goes on at the collision point, for still another constraint comes here from the beam-beam interaction which further restricts the choices available to the accelerator builder. The author also gives his impressions of the state of the technology available for building these kinds of machines within the next decade. The paper concludes with a brief recommendation for how we can all get on with the work faster, and hope to realize these machines sooner by working together. 10 refs., 9 figs.

Richter, B.

1987-11-01

413

Manipulation and electron-oscillation-measurement of laser accelerated electron beams  

NASA Astrophysics Data System (ADS)

Monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A stable electron beam is generated in the self-injection scheme by using a nitrogen gas jet target. We found the profile of the electron beam was manipulated by rotating the laser polarization. The electron beam is in the first bucket of the wake wave. In the energy space, transverse oscillation is observed when the laser pulse has S-polarization. The direction of the electron beam is controlled by the gas jet position.

Kotaki, H.; Hayashi, Y.; Kawase, K.; Mori, M.; Kando, M.; Homma, T.; Koga, J. K.; Daido, H.; Bulanov, S. V.

2011-01-01

414

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

415

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

SciTech Connect

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

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

2010-11-04

416

The continuous electron beam accelerator facility: Project status and physics outlook  

Microsoft Academic Search

Nuclear physics research program planning, accelerator tunnel construction, and accelerator component development, assembly, and testing are under way at the Continuous Electron Beam Accelerator Facility, Newport News, Virginia. CEBAF's 4-GeV, 200-muA superconducting recirculating accelerator will provide cw beam to simultaneous experiments in three end stations for studies of the nuclear many-body system, its quark substructure, and the strong and electroweak

Hermann A. Grunder

1990-01-01

417

The Continuous Electron Beam Accelerator Facility: Project status and physics outlook  

Microsoft Academic Search

Nuclear physics research program planning, accelerator tunnel construction, and accelerator component development, assembly, and testing are under way at the Continuous Electron Beam Accelerator Facility, Newport News, Virginia. CEBAF's 4-GeV, 200-μA superconducting recirculating accelerator will provide cw beam to simultaneous experiments in three end stations for studies of the nuclear many-body system, its quark substructure, and the strong and electroweak

Grunder

1989-01-01

418

Diocotron Instability of an Intense Relativistic Electron Beam in an Accelerator.  

National Technical Information Service (NTIS)

High current annular electron beam in an accelerator is subject to various instabilities. A general fluid-Maxwell theory of the diocotron instability is developed for an infinitely long and azimuthally symmetric annular electron beam propagating along an ...

H. C. Chen H. S. Uhm

1984-01-01

419

Beam envelope, injection, and acceleration in a compact, high-current, strong-focused recirculating accelerator scheme. Technical report  

SciTech Connect

In order to meet the criterion of compactness in developing high-current, high-energy electron accelerators, it is advantageous to recirculate the electron beam through an accelerating module. Various such recirculating-accelerator concepts that use strong-focusing magnetic fields may be conveniently referred to as SFRA (Strong Focused Recirculating Accelerators). The strong-focusing field can be produced by external current-carrying stellarator or torsatron windings. SLIA, Stellatron, RIA and rebatron are examples of SFRA. High current electron beam transport in externally applied stellarator and longitudinal magnetic fields is analyzed. It is shown that a constant of motion exists for a matched beam of rotating elliptical cross section, with self-fields included. A differential equation for the beam envelope is derived and is shown to reduce to the familiar beam envelope equation for a beam of circular cross section when the stellarator field is turned off. A summary description of beam dynamics of acceleration in one SFRA, the rebatron, is given. Although a rebatron with major radius 100 cm and minor radius 10 cm can accelerate electrons to gamma about 65 with a fixed vertical (bending) magnetic field, the insensitivity to energy mismatch poses a problem for beam-trapping and injection. It is shown that a beam trapping scheme, in which a rapidly varying vertical magnetic field is applied before activating the rebatron acceleration gap, would work for a 10-kA beam of 1-cm radius injected near the wall of a rebatron of minor radius 16 cm.

Prakash, A.

1988-12-01

420

Muon Cooling and Dynamics for Muon Colliders  

NASA Astrophysics Data System (ADS)

Muon Colliders have unique features, and disadvantages when compared to electron and/ or hadron accelerators. For example, in the muon collider Synchrotron radiation is negligible (to about 10TeV), the classical radius for the muon is about 200 times smaller and the number of collisions a bunch can make is proportional to the average bending field. The collider is circular and can be much smalller than a linear electron accelerator of the same energy. To obtain the needed collider luminosity, the phase-space volume must be greatly reduced within the muon life time. The Ioniza tion cooling is the preferred method used to compress the phase space and reduce the emittance to obtain high luminosity muon beams. We discuss the forlmalism, and the effects on the muon dynamics. We also discuss the codes used in the coolong simulations for the muon collider studies. (``Future High Energy Colliders'', edited by Z. Parsa, AIP CP 397, 1997.) (``Beam Stability and Nonlinear Dynamics'', edited by Z. Parsa, AIP CP405, 1997, pp. 165-172 and 183-188.) (Muon Collider Feasibility Study, BNL Report 52503 (1996); and references therein.)

Parsa, Zohreh

1998-04-01

421

Superconducting Super Collider 5T dipole magnet cryogenic design  

Microsoft Academic Search

Proposed colliding beam particle accelerators for high energy physics research will employ superconducting accelerator rings. The rings' superconducting magnet systems must provide the required magnetic function, have low refrigeration load, operate with very high reliability and be manufacturable at a low cost. The cryogenic aspects of a conceptual design for a 5T field, 5cm aperture, 12m long superconducting dipole magnet

R. C. Niemann; J. A. Carson; H. T. Edwards; N. Engler; J. D. Gonczy; R. W. Hanft; R. A. Lundy; P. M. Mantsch; A. D. McInturff; T. H. Nicol; R. J. Powers; R. Remsbottom; C. Rode; E. Schmidt; A. Szymulanski

1985-01-01

422

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

NASA Astrophysics Data System (ADS)

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

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

1999-06-01

423

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

424

Monte Carlo linear accelerator simulation of megavoltage photon beams: Independent determination of initial beam parameters  

SciTech Connect

Purpose: To individually benchmark the incident electron parameters in a Monte Carlo model of an Elekta linear accelerator operating at 6 and 15 MV. The main objective is to establish a simplified but still precise benchmarking procedure that allows accurate dose calculations of advanced treatment techniques. Methods: The EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc are used for photon beam simulations and dose calculations, respectively. A 5 x 5 cm{sup 2} field is used to determine both the incident electron energy and the electron radial intensity. First, the electron energy is adjusted to match the calculated depth dose to the measured one. Second, the electron radial intensity is adjusted to make the calculated dose profile in the penumbrae region match the penumbrae measured by GafChromic EBT film. Finally, the mean angular spread of the incident electron beam is determined by matching calculated and measured cross-field profiles of large fields. The beam parameters are verified for various field sizes and shapes. Results: The penumbrae measurements revealed a non-circular electron radial intensity distribution for the 6 MV beam, while a circular electron radial intensity distribution could best describe the 15 MV beam. These electron radial intensity distributions, given as the standard deviation of a Gaussian distribution, were found to be 0.25 mm (in-plane) and 1.0 mm (cross-plane) for the 6 MV beam and 0.5 mm (both in-plane and cross-plane) for the 15 MV beam. Introducing a small mean angular spread of the incident electron beam has a considerable impact on the lateral dose profiles of large fields. The mean angular spread was found to be 0.7 deg. and 0.5 deg. for the 6 and 15 MV beams, respectively. Conclusions: The incident electron beam parameters in a Monte Carlo model of a linear accelerator could be precisely and independently determined by the benchmarking procedure proposed. As the dose distribution in the penumbra region is insensitive to moderate changes in electron energy and angular spread, accurate penumbra measurements is feasible for benchmarking the electron radial intensity distribution. This parameter is particularly important for accurate dosimetry of mlc-shaped fields and small fields.

Almberg, Sigrun Saur; Frengen, Jomar; Kylling, Arve; Lindmo, Tore [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway) and Department of Oncology and Radiotherapy, St. Olavs University Hospital, NO-7006 Trondheim (Norway); Department of Oncology and Radiotherapy, St. Olavs University Hospital, NO-7006 Trondheim (Norway); Department of Oncology and Radiotherapy, Aalesund Hospital, NO-6026 Aalesund (Norway); Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

2012-01-15

425

Modification & alignment of beam line of 10 MeV RF electron beam accelerator  

NASA Astrophysics Data System (ADS)

A 10 MeV, 10 kW RF industrial Electron linac designed and developed at BARC is installed at the Electron Beam Center Kharghar, Navi Mumbai. The entire RF accelerator assembly consists of Electron gun, RF source, RF linac structure, Beam diagnostic chamber, Drift tube, Scanning magnet, Beam sensing aperture, Scan horn, and is spread over two floors at EBC. The paper discusses in detail about the alignment procedure adopted for the equipments of 10 MeV RF beamline. The complete electron beamline will be maintained under ultra high vacuum of the order of 10-7 torr. The paper discusses about the present problem of alignment, measurement technique of alignment, reason for misalignment, possible ways to solve the problem, equipment used for alignment, supports & arrestors, verification of alignment under vacuum

Barnwal, R.; Ghodke, S. R.; Bhattacharjee, D.; Kumar, M.; Jayaprakash, D.; Chindarkar, A. R.; Mishra, R. L.; Dolas, S.; Kulkarni, S. Y.; Kumar, M.; P, Dixit K.; S, Acharya; Barje, S. R.; Lawangare, N. K.; C, Saroj P.; Nimje, V. T.; Chandan, S.; Tillu, A. R.; V, Sharma; Chavan, R. B.; V, Yadav; P, Roychowdhury; Mittal, K. C.; Chakravarthy, D. P.; Ray, A. K.

2008-05-01

426

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

427

Propagation and post-acceleration of a pseudospark-sourced electron beam  

NASA Astrophysics Data System (ADS)

Propagation and post-acceleration of a pseudospark-sourced electron beam from a three-gap pseudospark discharge chamber were studied in recent experiments. The pseudospark produced an electron beam of two phases, an initial 22 kV, 50 A hollow cathode phase beam of brightness 109-10 Am-2 rad-2 followed by a 200 V, 200 A conductive phase (CP) beam of brightness 1011-12 Am-2 rad-2. The aim of these experiments was to post accelerate the lower-voltage, higher-current CP beam using an acceleration unit driven by a 40 kV, 125 ns voltage pulse produced by a cable Blumlein. The experiments were realized by attaching an acceleration unit to the downstream side of the anode of the discharge chamber. Both the pseudospark discharge and the cable Blumlein were triggered to ensure time correlation between initiation of the pseudospark discharge and post-acceleration of the beam.

Yin, H.; Cross, A. W.; Phelps, A. D. R.; Zhu, D.; He, W.; Ronald, K.

2002-04-01

428

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

429

The Stanford Linear Collider  

SciTech Connect

The Stanford Linear Collider (SLC) has been in operation for several years with the initial and accelerator physics experiments just completed. A synopsis of these results is included. The second round of experiments is now under preparation to install the new physics detector (SLD) in Fall 1990 and to increase the luminosity significantly by late 1991. Collisions at high intensity and with polarized electrons are planned. Many beam dynamics and technological advances are in progress to meet these goals. 10 refs., 15 figs., 1 tab.

Seeman, J.T.

1990-10-01

430

Photon desorption measurements of copper and copper plated beam tubes for the SSCL 20 TeV proton collider  

SciTech Connect

Relativistic protons circulating in the SSCL 20 TeV collider emit synchrotron radiation (10[sup 16] photons/m/s, [ital E][sub crit]=284 eV). This radiation will photodesorb gases from the walls of the beam tube. The 4.2 K superconducting magnet bore tubes will act as very long distributed pumps. Build up of cryosorbed gases could severely limit collider operation and may require a bore tube liner to hide cryosorbed molecules from the photon flux and to increase the H[sub 2] pumping capacity. To predict collider vacuum performance, photon stimulated desorption experiments have been running at the National Synchrotron Light Source (NSLS) at BNL and on the VEPP2M storage ring at BINP, Novosibirsk, Russia. At the U10B beamline of the VUV ring at NSLS, beam tube samples were exposed to over 10[sup 23] photons/m with [ital E][sub crit]=486 eV and incident angle=12 mrad. Unbaked copper and copper plated stainless steel have been tested. In addition, results have been obtained with a 1100 G dipole magnetic field and with a 350 [degree]C vacuum bake. Results are presented and compared with other measurements at the NSLS and at other laboratories.

Foerster, C.L.; Lanni, C. (Brookhaven National Laboratory, Upton, New York 11973 (United States)); Maslennikov, I.; Turner, W. (Superconducting Super Collider Laboratory, Dallas, Texas 75237 (United States))

1994-07-01

431

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

432

Emittance preservation in linear accelerators  

NASA Astrophysics Data System (ADS)

In linear colliders preservation of the phase space density of charged particles during acceleration to high energies is essential. In practice, the electromagnetic fields which govern the beam transport may not be sufficiently well understood. This may arise, for example, from magnet and structure alignment and/or manufacturing errors, time-varying electromagnetic fields due to component vibration or imperfect regulation, or at high beam currents, from beam-induced fields. These inadequacies may be overcome using measurements of the beam response. In this report we review such methods for preserving single-bunch beam emittances with experimental results from the Stanford Linear Collider. .

Minty, M.

2001-10-01

433

Multipath multicomponent self-accelerating beams through spectrum-engineered position mapping  

NASA Astrophysics Data System (ADS)

We introduce the concept of spatial spectral phase gradient, and demonstrate, both theoretically and experimentally, how this concept could be employed for generating single- and multipath self-accelerating beams. In particular, we show that the trajectories of the accelerating beams are determined a priori by different key spatial frequencies through direct spectrum-to-distance mapping. In the nonparaxial regime, our results clearly illustrate the breakup of Airy beams from a different perspective, and demonstrate how circular, elliptic, or hyperbolic accelerating beams can be created by judiciously engineering the spectral phase. Furthermore, we found that the accelerating beams still follow the predicted trajectory also for vectorial wave fronts. Our approach not only generalizes the idea of Fourier-space beam engineering along arbitrary convex trajectories, but also offers possibilities for beam or pulse manipulation not achievable through standard direct real-space approaches or by way of time-domain phase modulation.

Hu, Yi; Bongiovanni, Domenico; Chen, Zhigang; Morandotti, Roberto

2013-10-01

434

Characteristics of the photon beam from a new 25-MV linear accelerator  

SciTech Connect

The Therac 25 is a relatively compact therapy machine, the heart of which is a double-pass electron linear accelerator. The electron beam is injected into the accelerator at the treatment head end of the machine and is accelerated back down the arm to an energy of 13 MeV. At this end of the machine a magnet system reflects the beam back into the structure where it gains up to an additional 12 MeV of energy. After leaving the linear accelerator the beam is bent by an achromatic head magnet through 270 degrees to the treatment head. The machine produces eight electron beams and a 25-MV photon beam. In this work only the parameters of the photon beam are addressed based on measurements at the first two clinical sites. Percentage depth doses, tissue phantom ratios, and beam symmetry and stability are presented and discussed.

Aldrich, J.E.; Andrew, J.W.; Michaels, H.B.; O'Brien, P.F.

1985-09-01

435

Characteristics of the photon beam from a new 25-MV linear accelerator.  

PubMed

The Therac 25 is a relatively compact therapy machine, the heart of which is a double-pass electron linear accelerator. The electron beam is injected into the accelerator at the treatment head end of the machine and is accelerated back down the arm to an energy of 13 MeV. At this end of the machine a magnet system reflects the beam back into the structure where it gains up to an additional 12 MeV of energy. After leaving the linear accelerator the beam is bent by an achromatic head magnet through 270 degrees to the treatment head. The machine produces eight electron beams and a 25-MV photon beam. In this work only the parameters of the photon beam are addressed based on measurements at the first two clinical sites. Percentage depth doses, tissue phantom ratios, and beam symmetry and stability are presented and discussed. PMID:4046997

Aldrich, J E; Andrew, J W; Michaels, H B; O'Brien, P F

436

Beam-breakup calculations for the DARHT accelerator  

SciTech Connect

We have modeled an induction linac that will accelerate a 4-MeV, 3-kA beam of electrons to 16- to 20-MeV in 64 gaps. To suppress beam- breakup (BBU) instabilities induced by excitation of rf deflecting modes, the growth factor {Gamma} must be kept sufficiently small (e.g. < 3). On prototype DARHT cavities, rf measurements have shown that the normally degenerate TM modes are split in frequency by the asymmetry that the two pulsed-power drive rods present to the cavity. If half the cavities had vertical and half had horizontal drive-rod orientations, the effective number of gaps would be reduced by half if there were no coupling between the modes by the solenoidal focusing and if the split modes had no overlap. The LLNL code BREAKUP was used to study BBU growth for drive rod alternation patterns of blocks of 1, 2, 4, 8, 16, 24, 32, or 64 (no alternation) for both constant and alternating polarity solenoids. For alternating polarities the optimum alternation pattern is 2 or 4, whereas for constant polarities BBU is approximately independent of pattern. 9 refs., 5 figs. 2 tabs.

Allison, P.; Burns, M.J. (Los Alamos National Lab., NM (USA)); Caporaso, G.J.; Cole, A.G. (Lawrence Livermore National Lab., CA (USA))

1991-01-01

437

Decontamination of Ametryne HDPE packaging using electron beam accelerator  

NASA Astrophysics Data System (ADS)

This paper is part of a project to evaluate pesticide degradation on commercial polymeric (high-density polyethylene, HDPE) packaging material. The herbicide studied was Ametryne whose residues may be detectable in water, soil and on the surfaces for months or years, depending on the pesticide formulation and type of application. In order to evaluate the efficiency of radiation processing on removal of the pesticides contamination; the packaging material were irradiated using Radiation Dynamics Electron Beam Accelerator with 1,5 MeV energy and 37 kW, in batch system. The samples were irradiated with water, in various absorbed doses. Ametryne was analyzed by gas chromatography after extraction with hexane/dichloromethane (1:1 v/v) solution. The radiation processing yield was evaluated by the destruction G-value (Gd), and the electron beam irradiation processing, showed higher efficiency in destroying Ametryne in the HDPE packaging when the samples were irradiated in the presence of small quantities of water.

Duarte, C. L.; Andrade, D. C.; Melo, R. P.; Nagatomi, H. R.; Mori, M. N.

2009-07-01

438

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

439

EXTERNAL-BEAM ACCELERATED PARTIAL BREAST IRRADIATION USING MULTIPLE PROTON BEAM CONFIGURATIONS  

PubMed Central

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.; Woodward, Wendy A.; 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.

2011-01-01