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1

Beam-beam interactions in P-P colliding accelerators  

SciTech Connect

Non-linear stop-bands, due to the beam-beam interaction in a P-P colliding accelerator, are computed and used to estimate the strength of the beam-beam interaction. Results for the stop-band widths due to various causes are summarized. These results are used to compare the effects of beam-beam non-linear resonances in the ISR with those in CBA (Colliding Beam Accelerator at BNL), to estimate the effect of a spectrometer magnet placed at one of the beam crossing points, and to compare the beam-beam interactions for colliding beam accelerators with different crossing angles and different ..beta..-functions at the crossing points.

Parzen, G.

1983-01-01

2

Design principles for high quality electron beams via colliding pulses in laser plasma accelerators  

NASA Astrophysics Data System (ADS)

Laser plasma based accelerators have the potential to reduce dramatically the size and cost of future particle colliders and light sources. Production of high quality beams along with reproducibility, tunability, and efficiency are required for many applications. We present design principles for two-pulse colliding laser pulse injection mechanisms, which can meet these requirements. Simulations are used to determine the best conditions for the production of high quality beams: high charge, low energy spread, and low emittance. Simulations also allow access to the internal dynamics of the interaction, providing insight regarding further improvement of the beam quality. We find that a 20 pC beam can be accelerated to 300 MeV in 4 mm with only a few percent energy spread and transverse normalized emittance close to 1 mm mrad, using a 10 TW laser. We demonstrate that this design scales according to linear theory. Control of the laser pulse mode content and subsequent evolution in the plasma channel are shown to be critical for achieving the highest beam quality.

Cormier-Michel, E.; Ranjbar, V. H.; Bruhwiler, D. L.; Cary, J. R.; Chen, M.; Geddes, C. G. R.; Plateau, G. R.; Matlis, N. H.; Leemans, W. P.

2014-09-01

3

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

4

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

5

Laser plasma accelerator: Control of electron beam parameters in colliding laser pulses scheme  

NASA Astrophysics Data System (ADS)

Stable and high quality electron beams are produced when two laser pulses collide in underdense plasmas. In addition to the improvement of the stability of the electron beam, the use of a second laser pulse allows the control of the electron beam parameters (energy, relative energy spread, and charge). The experimental features are well explained by the use of PIC simulations which underline physics processes which were not predicted by fluid model. This control is obtained by changing laser pulse energy, laser pulses polarization or electron density. With a total of 1 J laser energy, a 10 pC electron beam at 200 MeV with relative energy spread smaller than 1% has been measured for the first time. Using higher laser energy PIC simulations predicted that 3 GeV electron beam with 0.9% should be produced in this scheme after 3.8 cm propagation length. In collaboration with J. Faure and C. Rechatin, Laboratoire d'Optique Appliqu'ee, 'Ecole Nationale Sup'erieure de Techniques Avanc'ees, 'Ecole Polytechnique, CNRS, UMR 7639, 91761 Palaiseau, France; A. Ben-Ismail, Laboratoire d'Optique Appliqu'ee, and LLR, 'Ecole polytechnique, CNRS-IN2P3, 91128 Palaiseau, France; J. Lim, Laboratoire d'Optique Appliqu'ee; X. Davoine and E. Lefebvre, Commissariat àl'Energie Atomique, DIF, Bruyères-le-Châtel, France; and A. Specka and H. Videau, LLR, 'Ecole polytechnique. [2pt] This work has been partially supported by ANR-05-NT05-2-41699, by the European Community Research Infrastructure Activity under the FP6 Structuring the European Research Area program (CARE, contract number RII3-CT-2003-506395 and EU-ROLEAP, contract number 028514).

Malka, V.

2008-11-01

6

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

7

Generating High-Brightness Electron Beams via Ionization Injection by Transverse Colliding Lasers in a Plasma-Wakefield Accelerator  

NASA Astrophysics Data System (ADS)

The production of ultrabright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional particle-in-cell simulations. The relatively low intensity lasers are polarized along the wake axis and overlap with the wake for a very short time. The result is that the residual momentum of the ionized electrons in the transverse plane of the wake is reduced, and the injection is localized along the propagation axis of the wake. This minimizes both the initial thermal emittance and the emittance growth due to transverse phase mixing. Simulations show that ultrashort (˜8fs) high-current (0.4 kA) electron bunches with a normalized emittance of 8.5 and 6 nm in the two planes, respectively, and a brightness of 1.7×1019Arad-2m-2 can be obtained for realistic parameters.

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

2013-07-01

8

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

9

The CERN antiproton collider programme: accelerators and accumulation rings  

NASA Astrophysics Data System (ADS)

One of CERN's most daring and successful undertakings was the quest for the intermediate bosons, W and Z. In this paper, we describe the accelerator part of the venture which relied on a number of innovations: an extension of the budding method of stochastic cooling by many orders of magnitude; the construction of the Antiproton Accumulator, depending on several novel accelerator methods and technologies; major modifications to the 26 GeV PS Complex; and the radical conversion of the 300 GeV SPS, which just had started up as an accelerator, to a proton-antiproton collider. The SPS Collider had to master the beam-beam effect far beyond limits reached ever before and had to function in a tight symbiosis with the huge detectors UA1 and UA2.

Koziol, H.; Möhl, D.

2004-12-01

10

The Two-beam accelerator  

SciTech Connect

The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field, induction accelerator units are placed periodically along the length of the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have a serious option for a 1 TeV x 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron Laser Facility (ELF). Description is given of a first test at ELF with a seven-cell 2..pi../3 mode structure which without preconditioning and with a not-very-good vacuum nevertheless at 35 GHz yielded an average accelerating gradient of 180 MV/m.

Sessler, A.M.; Hopkins, D.B.

1986-06-01

11

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

12

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

E-print Network

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

Geddes, Cameron Guy Robinson

13

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

SciTech Connect

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

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

2013-06-01

14

Beam Dynamics Challenges in High Energy Physics Accelerators!  

E-print Network

Beam Dynamics Challenges in High Energy Physics Accelerators! Alexander Valishev! University! 12/1/2014!A. Valishev | Beam Dynamics Challenges in HEP Accelerators!3! ENERGY INTENSITY BRIGHTNESS more #12;Energy Frontier ­ the Past of Colliders! 12/1/2014!A. Valishev | Beam Dynamics Challenges

15

Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams  

SciTech Connect

Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

Siemann, R.H.; /SLAC

2011-10-24

16

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

17

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

18

Accelerator-driven modular aneutronic production of tritium from D+D?T+p+4MeV in self-colliding beams of deuterons (without target or blanket)  

Microsoft Academic Search

The advent of neutralized Self-Colliders(SC) has opened the way for collision rates or ‘‘luminosity’’ L, (reaction rate for ?=1), orders of magnitude greater than obtained in colliding beams or beam-on-target experiments, L?1×1041 cm?2 s?1, This facilitates direct production of tritium in self-colliding beams in the reaction d+d?T+p+4 MeV. The tritons are extracted as a beam, decelerated, neutralized, and stored as

Bogdan C. Maglich; Tsuey-Fen Chang; Dan Arthur Gross

1995-01-01

19

Electron beam quality in a cyclotron autoresonance accelerator  

Microsoft Academic Search

An analysis of the electron beam dynamics in a cyclotron autoresonance accelerator (CARA) is presented. The beam is to be employed in harmonic convertor experiments to generate high-power centimeter-wavelength microwaves, with potential application as a driver for a next-generation electron-positron collider. The presentation will highlight the quality of the electron beam generated by this acceleration mechanism. For beam energies up

B. Hafizi; P. Sprangle; J. L. Hirshfield

1994-01-01

20

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

21

Colliding Laser Pulses for Laser-Plasma Accelerator Injection Control  

E-print Network

Colliding Laser Pulses for Laser-Plasma Accelerator Injection Control G. R. Plateau, , C. G. R acceleration is a key challenge to achieve compact, reliable, tunable laser-plasma accelerators (LPA) [1, 2]. In colliding pulse injection the beat between multiple laser pulses can be used to control energy, energy

Geddes, Cameron Guy Robinson

22

Colliding beam fusion reactor space propulsion system  

Microsoft Academic Search

We describe a space propulsion system based on the Colliding Beam Fusion Reactor (CBFR). The CBFR is a high-beta, field-reversed, magnetic configuration with ion energies in the range of hundreds of keV. Repetitively-pulsed ion beams sustain the plasma distribution and provide current drive. The confinement physics is based on the Vlasov-Maxwell equation, including a Fokker Planck collision operator and all

Frank J. Wessel; Michl W. Binderbauer; Norman Rostoker; Hafiz Ur Rahman; Joseph O'Toole

2000-01-01

23

62-TeV center of mass hadron collider with capability for super bunch beams  

SciTech Connect

A 60 TeV center of mass hadron collider is proposed, which has capability of using Superbunch beam. With Superbunch beam, the luminosity is expected to be increased by a factor of 20, compared with conventional acceleration using RF cavities. This hadron collider will be built in two stages with a low field magnet ring first and a high field magnet ring later in the same tunnel. The low field magnet rig will be built with Pipetron scheme, with 7 TeV and 7 TeV proton beams, making a 14 TeV center of mass energy high luminosity collider, using Superbunch beams. In the second stage 10 Tesla high field magnets with twin beams, will be installed. It also utilizes Superbunch beams, realizing high luminosity collider. To accelerate Superbunch beams, the barrier bucket and acceleration induction cells will be used, which are made of induction cells, utilizing FINEMET material. The core loss of the FINEMET is estimated for the whole collider is estimated. The synchrotron radiation of the collider is also estimated. Merits of Superbunch beams over RF bunched beams for the high energy experiments is described.

Ryuji Yamada and Ken Takayama

2001-08-22

24

RF properties of periodic accelerating structures for linear colliders  

SciTech Connect

With the advent of the SLAC electron-positron linear collider (SLC) in the 100 GeV center-of-mass energy range, research and development work on even higher energy machines of this type has started in several laboratories in the United States, Europe, the Soviet Union and Japan. These linear colliders appear to provide the only promising approach to studying e/sup /plus//e/sup /minus// physics at center-of-mass energies approaching 1 TeV. This thesis concerns itself with the study of radio frequency properties of periodic accelerating structures for linear colliders and their interaction with bunched beams. The topics that have been investigated are: experimental measurements of the energy loss of single bunches to longitudinal modes in two types of structures, using an equivalent signal on a coaxial wire to simulate the beam; a method of canceling the energy spread created within a single bunch by longitudinal wakefields, through appropriate shaping of the longitudinal charge distribution of the bunch; derivation of the complete transient beam-loading equation for a train of bunches passing through a constant-gradient accelerator section, with application to the calculation and minimization of multi-bunch energy spread; detailed study of field emission and radio frequency breakdown in disk-loaded structures at S-, C- and X-band frequencies under extremely high-gradient conditions, with special attention to thermal effects, radiation, sparking, emission of gases, surface damage through explosive emission and its possible control through RF-gas processing. 53 refs., 49 figs., 9 tabs.

Wang, J.W.

1989-07-01

25

The International Linear Collider Beam Dumps  

SciTech Connect

The ILC beam dumps are a key part of the accelerator design. At Snowmass 2005, the current status of the beam dump designs was reviewed, and the options for the overall dump layout considered. This paper describes the available dump options for the baseline and the alternatives and considers issues for the dumps that require resolution.

Appleby, R.; /Cockcroft Inst.; Keller, L.; Markiewicz, T.; Seryi, A.; Walz, D.; /SLAC; Sugahara, R.; /KEK, Tsukuba

2006-01-30

26

Two-Beam Accelerator: structure studies and 35 GHz experiments  

SciTech Connect

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

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

1985-05-01

27

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

Microsoft Academic Search

In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of the SciDAC-2 accelerator project 'Community Petascale Project for Accelerator Science and Simulation (ComPASS).' Several parallel computational tools for beam dynamics simulation are described. Also presented are number of applications in current and future accelerator facilities

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

2008-01-01

28

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

29

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

SciTech Connect

In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of the SciDAC-2 accelerator project 'Community Petascale Project for Accelerator Science and Simulation (ComPASS).' Several parallel computational tools for beam dynamics simulation are described. Also presented are number of applications in current and future accelerator facilities (e.g., LCLS, RHIC, Tevatron, LHC, and ELIC).

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

2008-08-01

30

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

Microsoft Academic Search

In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of the SciDAC-2 accelerator project 'Community Petascale Project for Accelerator Science and Simulation (ComPASS).' Several parallel computational tools for beam dynamics simulation are described. Also presented are number of applications in current and future accelerator facilities

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

2011-01-01

31

Colliding Beam Fusion Reactor Space Propulsion System  

Microsoft Academic Search

The Colliding Beam Fusion Reactor Space Propulsion System, CBFR-SPS, is an aneutronic, magnetic-field-reversed configuration, fueled by an energetic-ion mixture of hydrogen and boron11 (H-B11). Particle confinement and transport in the CBFR-SPS are classical, hence the system is scaleable. Fusion products are helium ions, alpha-particles, expelled axially out of the system. alpha-particles flowing in one direction are decelerated and their energy

A. Cheung; M. Binderbauer; F. Liu; A. Qerushi; N. Rostoker; F. J. Wessel

2004-01-01

32

COLLIDING PULSE INJECTION CONTROL IN A LASER-PLASMA ACCELERATOR  

E-print Network

COLLIDING PULSE INJECTION CONTROL IN A LASER-PLASMA ACCELERATOR C.G.R. Geddes , G.R. Plateau, M is presented using the beat between two 'collid- ing' laser pulses to kick electrons into the plasma wake such that the pulse length is in the range of one plasma period. Three pulse schemes with a separate driver and two

Geddes, Cameron Guy Robinson

33

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

SciTech Connect

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

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

2011-11-14

34

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

35

Accelerator-driven modular aneutronic production of tritium from D+D?T+p+4MeV in self-colliding beams of deuterons (without target or blanket)  

NASA Astrophysics Data System (ADS)

The advent of neutralized Self-Colliders(SC) has opened the way for collision rates or ``luminosity'' L, (reaction rate for ?=1), orders of magnitude greater than obtained in colliding beams or beam-on-target experiments, L?1×1041 cm-2 s-1, This facilitates direct production of tritium in self-colliding beams in the reaction d+d?T+p+4 MeV. The tritons are extracted as a beam, decelerated, neutralized, and stored as gas. Calculations, supported by experiments and a 3-dimensional Fokker Planck simulation on CRAY-2 of a strong focusing self-collider filled with 0.75 MeV deuterons of density 3.2×1014 cm-3, indicated that one cell would produce 10 grams of tritium per year in a 10 liter volume at an electricity cost of 42 MWh per gram (2,100 per gram). Laboratory benchmark test results with tritium production in SC are presented. Conceptual design of modular production plant units consisting of 10 cells and producing ?100 g/year will be described. This technique does not require tritium. Tritons are extracted with purity at the 1 ppm level, there is no lithium blanket and not tritium processing requirement for chemical extraction, purification or separation.

Maglich, Bogdan C.; Chang, Tsuey-Fen; Gross, Dan Arthur

1995-01-01

36

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

37

A new method for RF power generation for two-beam linear colliders  

SciTech Connect

In this paper we discuss a new approach to two-beam acceleration. The energy for RF production is initially stored in a long-pulse electron beam which is efficiently accelerated to about 1.2 GeV by a fully loaded, conventional, low frequency ({approximately}1 GHz) linac. The beam pulse length is twice the length of the high-gradient linac. Segments of this long pulse beam are compressed using combiner rings to create a sequence of higher peak power drive beams with gaps in between. This train of drive beams is distributed from the end of the linac against the main beam direction down a common transport line so that each drive beam can power a section of the main linac. After a 180-degree turn, each high-current, low-energy drive beam is decelerated in low-impedance decelerator structures, and the resulting power is used to accelerate the low-current, high-energy beam in the main linac. The method discussed here seems relatively inexpensive, is very flexible and can be used to accelerate beams for linear colliders over the entire frequency and energy range. {copyright} {ital 1999 American Institute of Physics.}

Braun, H.; Corsini, R.; DAmico, T.; Delahaye, J.P.; Guignard, G.; Johnson, C.; Millich, A.; Pearce, P.; Rinolfi, L.; Riche, A.; Schulte, D.; Thorndahl, L.; Valentini, M.; Wilson, I. [CERN, Geneva (Switzerland); Ruth, R.D. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)

1999-05-01

38

A new method for RF power generation for two-beam linear colliders  

SciTech Connect

In this paper we discuss a new approach to two-beam acceleration. The energy for RF production is initially stored in a long-pulse electron beam which is efficiently accelerated to about 1.2 GeV by a fully loaded, conventional, low frequency ({approx}1 GHz) linac. The beam pulse length is twice the length of the high-gradient linac. Segments of this long pulse beam are compressed using combiner rings to create a sequence of higher peak power drive beams with gaps in between. This train of drive beams is distributed from the end of the linac against the main beam direction down a common transport line so that each drive beam can power a section of the main linac. After a 180-degree turn, each high-current, low-energy drive beam is decelerated in low-impedance decelerator structures, and the resulting power is used to accelerate the low-current, high-energy beam in the main linac. The method discussed here seems relatively inexpensive, is very flexible and can be used to accelerate beams for linear colliders over the entire frequency and energy range.

Braun, H.; Corsini, R.; D'Amico, T.; Delahaye, J. P.; Guignard, G.; Johnson, C.; Millich, A.; Pearce, P.; Rinolfi, L.; Riche, A.; Schulte, D.; Thorndahl, L.; Valentini, M.; Wilson, I.; Ruth, R. D. [CERN, Geneva (Switzerland); Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)

1999-05-07

39

Two Methods for Simulating the Strong--Strong Beam--Beam Interaction in Hadron Colliders  

E-print Network

Two Methods for Simulating the Strong--Strong Beam--Beam Interaction in Hadron Colliders Mathias and dissipa­ tion) and the hadron codes BBPFmD (Beam--Beam Perron-- Frobenius) and BBDeMomD (Beam is described in detail in [1]. Here we will concentrate on the completely symplectic hadron codes. 2 MODELS

Ellison, James

40

Accelerator physics in RHIC (Relativistic Heavy Ion Collider)  

SciTech Connect

RHIC (for Relativistic Heavy Ion Collider) is a colliding beam facility to be built at BNL in the tunnel system that was constructed for the defunct ISABELLE/CBA project. It is intended for the study of collisions between fully stripped ions of the same or different species with magnetic rigidities of up to at least 839.5 Tm, corresponding with an energy of 100 GeV/amu (amu for atomic mass unit) for particles with A/Z = 2.5, and 251 GeV for protons. There are six potential crossing regions, each with, initially, time average luminosities of up to a few times 10/sup 26/ cm/sup -2/ sec/sup -1/ for Au, with luminosity life-times of 10 hours for Au, and longer for the lighter ions. The initial proton-proton luminosity will be about 10/sup 31/ cm/sup -2/ sec/sup -1/. The rms length of the interaction diamond is 0.2 m when the beams collide colinearly, it is determined by the lengths of the colliding bunches. The diamond length can be reduced by having the beams cross at an angle, but this reduces the luminosity. The magnitude of the crossing angle is restricted geometrically in dependence of the energies and species of the interacting ions and possibly also by dynamic effects in the circulating beams. The distance between each crossing point and the nearest machine component is 9 m on each side, this space is available for experimental equipment. The performance quoted assumes that each ring contains 57 bunches, each bunch with 10/sup 9/ Au ions, resp 10/sup 11/ protons and with invariant emittances of 10..pi.., resp 20..pi.. mm-mrad, and ..beta../sub x/* = ..beta../sub y/* = 3 m. The beam-beam tune-shift per crossing point at these intensities is 0.0025, resp 0.0037. 5 refs., 4 figs.

Claus, J.

1988-01-01

41

Effect of 3D Polarization profiles on polarization measurements and colliding beam experiments  

SciTech Connect

The development of polarization profiles are the primary reason for the loss of average polarization. Polarization profiles have been parametrized with a Gaussian distribution. We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the figure of merit in single and double spin experiments. Examples from RHIC are provided. The Relativistic Heavy Ion Collider (RHIC) is the only collider of spin polarized protons. During beam acceleration and storage profiles of the polarization P develop, which affect the polarization measured in a polarimeter, and the polarization and figure of merit (FOM) in colliding beam experiments. We calculate these for profiles in all dimensions, and give examples for RHIC. Like in RHIC we call the two colliding beams Blue and Yellow. We use the overbar to designate intensity-weighted averages in polarimeters (e.g. {bar P}), and angle brackets to designate luminosity-weighted averages in colliding beam experiments (e.g.

).

Fischer, W.; Bazilevsky, A.

2011-08-18

42

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOEpatents

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

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

1984-03-22

43

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

44

Ion beam parameters of a plasma accelerator  

SciTech Connect

The aim of this investigation was to determine the dependences of the current density, the energy, and the divergence of the ion beams of an UZDP-type source (a plasma accelerator with closed electron drift in the accelerator channel and an extended zone of ion acceleration) on the parameters which determine its performance, and to establish qualitative relationships between these values.

Nazarov, V.G.; Vinogradov, A.M.; Veselovzorov, A.N.; Efremov, V.K.

1987-08-01

45

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

46

Single bunch beam measurements for the proposed SLAC linear collider  

SciTech Connect

Single S-band bunches of approx. 10/sup 9/ electrons have been used to study the characteristics of the SLAC linac in anticipation of its operation as a linear collider. Emittance measurements have been made, the longitudinal charge distribution within single bunches has been determined and transverse emittance growth has been produced by deliberately missteering the beam. New equipment is being installed and checked out, and the sensitivity of new traveling-wave beam position monitors has been measured.

Clendenin, J.E.; Loew, G.A.; Miller, R.H.; Pellegrin, J.L.; Truher, J.B.

1981-02-01

47

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

48

Accelerating light beams with arbitrarily transverse shapes.  

PubMed

Accelerating beams are wave packets that preserve their shape while propagating along curved trajectories. Their unique characteristics have opened the door to applications that range from optical micromanipulation and plasma-channel generation to laser micromachining. Here, we demonstrate, theoretically and experimentally, that accelerating beams can be generated with a variety of arbitrarily chosen transverse shapes. We present a general method to construct such beams in the paraxial and nonparaxial regime and demonstrate experimentally their propagation in the paraxial case. The key ingredient of our method is the use of the spectral representation of the accelerating beams, which offers a unique and compact description of these beams. The on-demand accelerating light patterns described here are likely to give rise to new applications and add versatility to the current ones. PMID:24663639

Ruelas, Adrian; Davis, Jeffrey A; Moreno, Ignacio; Cottrell, Don M; Bandres, Miguel A

2014-02-10

49

A concept of the photon collider beam dump  

NASA Astrophysics Data System (ADS)

Photon beams at photon colliders are very narrow, powerful (10–15 MW) and cannot be spread by fast magnets (because photons are neutral). No material can withstand such energy density. For the ILC-based photon collider, we suggest using a 150 m long, pressurized (P ~ 4 atm) argon gas target in front of a water absorber which solves the overheating and mechanical stress problems. The neutron background at the interaction point is estimated and additionally suppressed using a 20 m long hydrogen gas target in front of the argon.

Shekhtman, L. I.; Telnov, V. I.

2014-09-01

50

A concept of the photon collider beam dump  

E-print Network

Photon beams at photon colliders are very narrow, powerful (10--15 MW) and cannot be spread by fast magnets (because photons are neutral). No material can withstand such energy density. For the ILC-based photon collider, we suggest using a 150 m long, pressurized (P ~ 4 atm) argon gas target in front of a water absorber which solves the overheating and mechanical stress problems. The neutron background at the interaction point is estimated and additionally suppressed using a 20 m long hydrogen gas target in front of the argon.

L. I. Shekhtman; V. I. Telnov

2014-09-19

51

Application of International Linear Collider superconducting cavities for acceleration of protons  

NASA Astrophysics Data System (ADS)

Beam acceleration in the International Linear Collider (ILC) will be provided by 9-cell 1300 MHz superconducting (SC) cavities. The cavities are designed for effective acceleration of charged particles moving with the speed of light and are operated on ?-mode to provide a maximum accelerating gradient. A significant research and development effort has been devoted to develop ILC SC technology and its rf system which resulted in excellent performance of ILC cavities. Therefore, the proposed 8-GeV proton driver in Fermilab is based on ILC cavities above ˜1.2GeV. The efficiency of proton beam acceleration by ILC cavities drops fast for lower velocities and it was proposed to develop squeezed ILC-type (S-ILC) cavities operating at 1300 MHz and designed for ?G=0.81, geometrical beta, to accelerate protons or H- from ˜420MeV to 1.2 GeV. This paper discusses the possibility of avoiding the development of new ?G=0.81 cavities by operating ILC cavities on (8)/(9)?-mode of standing wave oscillations.

Ostroumov, P. N.; Aseev, V. N.; Gonin, I. V.; Rusnak, B.

2007-12-01

52

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

SciTech Connect

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

Chin, Y.H.

1989-07-01

53

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

SciTech Connect

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

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

2010-09-27

54

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

55

Microwave accelerator E-beam pumped laser  

DOEpatents

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

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

1980-01-01

56

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

57

Accelerator Physics Related to Rare Isotope Beams  

NASA Astrophysics Data System (ADS)

Extensive analysis of the existing data and theoretical models has suggested that the highest yield for a wide range of rare isotopes available for experiments can be obtained by using two accelerators: a heavy-ion driver and a post-accelerator for re-acceleration of radioisotopes. The superconducting driver linac provides the primary, 400 kW, stable-ion beams in the energy range from 580 MeV for protons to 200 MeV/u for uranium required to produce the radioisotopes. To overcome intensity limitations from the most advanced ECR ion sources, the driver linac is designed for the simultaneous acceleration of two charge-states of uranium ions in the front-end and 5 charge states of uranium ions after the liquid lithium stripper. The most efficient production mechanisms for slow radioactive ions produce these ions in 1^+ or 2^+ charge states. The post-accelerator must, therefore, be able to accept such low charge-to-mass ratio ions. However, this option results in an expensive post-accelerator. One approach is to increase the charge state of the ions before acceleration via a charge booster stage. The intensity of rare isotope beams can be enhanced by the acceleration of multiple charge state beams.

Ostroumov, Peter

2008-04-01

58

Linear Colliders  

NASA Astrophysics Data System (ADS)

An overview of linear collider programs is given. The history and technical challenges are described and the pioneering electron-positron linear collider, the SLC, is first introduced. For future energy frontier linear collider projects, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are introduced and their technical features are discussed. The ILC is based on superconducting RF technology and the CLIC is based on two-beam acceleration technology. The ILC collaboration completed the Technical Design Report in 2013, and has come to the stage of "Design to Reality." The CLIC collaboration published the Conceptual Design Report in 2012, and the key technology demonstration is in progress. The prospects for further advanced acceleration technology are briefly discussed for possible long-term future linear colliders.

Yamamoto, Akira; Yokoya, Kaoru

2015-02-01

59

Beam-beam Effects of 'Gear-changing' in Ring-Ring Colliders  

E-print Network

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

Hao, Yue; Ptitsyn, Vadim

2013-01-01

60

Heavy ion beam loss mechanisms at an electron-ion collider  

E-print Network

There are currently several proposals to build a high-luminosity electron-ion collider, to study the spin structure of matter and measure parton densities in heavy nuclei, and to search for gluon saturation and new phenomena like the colored glass condensate. These measurements require operation with heavy-nuclei. We calculate the cross-sections for two important processes that will affect accelerator and detector operations: bound-free pair production, and Coulomb excitation of the nuclei. Both of these reactions have large cross-sections, 28-56 mb, which can lead to beam ion losses, produce beams of particles with altered charge:mass ratio, and produce a large flux of neutrons in zero degree calorimeters. The loss of beam particles limits the sustainable electron-ion luminosity to levels of several times $10^{32}/$cm$^2$/s.

Spencer R. Klein

2014-09-18

61

Target Material Irradiation Studies for High-Intensity Accelerator Beams , H. Ludewig1  

E-print Network

Target Material Irradiation Studies for High-Intensity Accelerator Beams N. Simos1* , H. Kirk1 , H on the behavior of special materials and composites under irradiation conditions and their potential use material matrix geared toward the neutrino superbeam and muon collider initiatives. * Work performed under

McDonald, Kirk

62

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

63

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

64

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

65

A Radioactive Ion Beam Accelerator Concept Based on Linear Accelerators  

NASA Astrophysics Data System (ADS)

A concept for an accelerator complex for efficiently producing high-quality radioactive beams at Coulomb barrier energies and higher will be presented. A high-power driver accelerator would be used to produce radionuclides in a target that is closely coupled to an ion source and mass separator, i.e. an Isotope-Separator-On-Line (ISOL) system. A challenge is to achieve high efficiency for the release, ionization, and acceleration of isotopes over a broad mass range, from atomic masses as low as 6 to well over mass 100. The scheme utilizes existing ISOL-type 1+ ion source technology followed by CW Radio Frequency Quadrupole (RFQ) accelerators and superconducting linacs. Over 95% of the total acceleration is done by the superconducting linacs. A benchmark beam, ^132Sn, would require two stripping stages, one a gas stripper at very low velocity after the first RFQ section, and one a foil stripper at higher velocity after a superconducting-linac injector. Ions with mass 66 or less would require only the foil stripper.

Nolen, Jerry

1998-04-01

66

Thermomechanical assessment of the effects of a jaw-beam angle during beam impact on Large Hadron Collider collimators  

NASA Astrophysics Data System (ADS)

The correct functioning of a collimation system is crucial to safely and successfully operate high-energy particle accelerators, such as the Large Hadron Collider (LHC). However, the requirements to handle high-intensity beams can be demanding, and accident scenarios must be well studied in order to assess if the collimator design is robust against possible error scenarios. One of the catastrophic, though not very probable, accident scenarios identified within the LHC is an asynchronous beam dump. In this case, one (or more) of the 15 precharged kicker circuits fires out of time with the abort gap, spraying beam pulses onto LHC machine elements before the machine protection system can fire the remaining kicker circuits and bring the beam to the dump. If a proton bunch directly hits a collimator during such an event, severe beam-induced damage such as magnet quenches and other equipment damage might result, with consequent downtime for the machine. This study investigates a number of newly defined jaw error cases, which include angular misalignment errors of the collimator jaw. A numerical finite element method approach is presented in order to precisely evaluate the thermomechanical response of tertiary collimators to beam impact. We identify the most critical and interesting cases, and show that a tilt of the jaw can actually mitigate the effect of an asynchronous dump on the collimators. Relevant collimator damage limits are taken into account, with the aim to identify optimal operational conditions for the LHC.

Cauchi, Marija; Assmann, R. W.; Bertarelli, A.; Carra, F.; Lari, L.; Rossi, A.; Mollicone, P.; Sammut, N.

2015-02-01

67

Laser Triggered Injection of Electrons in a Laser Wakefield Accelerator with the Colliding Pulse  

E-print Network

into the accelerating field of the plasma wave is problematic using conventional RF technology, since the characteristic of accelerating field is required, which is beyond the performance of current conventional accelerator technology (colliding with the drive laser pulse, used to generate a plasma wake) is discussed. The threshold laser

Geddes, Cameron Guy Robinson

68

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider  

NASA Astrophysics Data System (ADS)

The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

2014-08-01

69

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

SciTech Connect

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

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

1998-06-22

70

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

SciTech Connect

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

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

1998-08-01

71

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

E-print Network

Design and Interpretation of Colliding Pulse Injected Laser-Plasma Acceleration Experiments Estelle Abstract. The use of colliding laser pulses to control the injection of plasma electrons into the plasma with experimental data. Effect of non-ideal gaussian pulses and laser self-focusing in the plasma channel

Geddes, Cameron Guy Robinson

72

High-efficiency acceleration of an electron beam in a plasma wakefield accelerator.  

PubMed

High-efficiency acceleration of charged particle beams at high gradients of energy gain per unit length is necessary to achieve an affordable and compact high-energy collider. The plasma wakefield accelerator is one concept being developed for this purpose. In plasma wakefield acceleration, a charge-density wake with high accelerating fields is driven by the passage of an ultra-relativistic bunch of charged particles (the drive bunch) through a plasma. If a second bunch of relativistic electrons (the trailing bunch) with sufficient charge follows in the wake of the drive bunch at an appropriate distance, it can be efficiently accelerated to high energy. Previous experiments using just a single 42-gigaelectronvolt drive bunch have accelerated electrons with a continuous energy spectrum and a maximum energy of up to 85 gigaelectronvolts from the tail of the same bunch in less than a metre of plasma. However, the total charge of these accelerated electrons was insufficient to extract a substantial amount of energy from the wake. Here we report high-efficiency acceleration of a discrete trailing bunch of electrons that contains sufficient charge to extract a substantial amount of energy from the high-gradient, nonlinear plasma wakefield accelerator. Specifically, we show the acceleration of about 74 picocoulombs of charge contained in the core of the trailing bunch in an accelerating gradient of about 4.4 gigavolts per metre. These core particles gain about 1.6 gigaelectronvolts of energy per particle, with a final energy spread as low as 0.7 per cent (2.0 per cent on average), and an energy-transfer efficiency from the wake to the bunch that can exceed 30 per cent (17.7 per cent on average). This acceleration of a distinct bunch of electrons containing a substantial charge and having a small energy spread with both a high accelerating gradient and a high energy-transfer efficiency represents a milestone in the development of plasma wakefield acceleration into a compact and affordable accelerator technology. PMID:25373678

Litos, M; Adli, E; An, W; Clarke, C I; Clayton, C E; Corde, S; Delahaye, J P; England, R J; Fisher, A S; Frederico, J; Gessner, S; Green, S Z; Hogan, M J; Joshi, C; Lu, W; Marsh, K A; Mori, W B; Muggli, P; Vafaei-Najafabadi, N; Walz, D; White, G; Wu, Z; Yakimenko, V; Yocky, G

2014-11-01

73

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

74

High-powered pulsed-ion-beam acceleration and transport  

SciTech Connect

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

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

1981-11-01

75

High Energy Colliding Beams; What Is Their Future?  

NASA Astrophysics Data System (ADS)

The success of the first few years of LHC operations at CERN, and the expectation of more to come as the LHC's performance improves, are already leading to discussions of what should be next for both proton-proton and electron-positron colliders. In this discussion I see too much theoretical desperation caused by the so-far-unsuccessful hunt for what is beyond the Standard Model, and too little of the necessary interaction of the accelerator, experimenter, and theory communities necessary for a scientific and engineering success. Here, I give my impressions of the problem, its possible solution, and what is needed to have both a scientifically productive and financially viable future.

Richter, Burton

2015-02-01

76

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

77

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

SciTech Connect

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

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

1998-08-01

78

Radioactive beams with the HHIRF accelerators  

Microsoft Academic Search

It is pointed out that the two accelerators of the Holifield Heavy Ion Research Facility (HHIRF) provide a unique opportunity to quickly and economically develop an interim proton-rich, medium-intensity, ISOL-type, RIB (radioactive ion beam) facility. This extension of the HHIRF would provide for research and development until the much larger facility can be realized in the late 1990s. Presently, the

D. K. Olsen; G. D. Alton; C. Baktash; H. K. Carter; D. T. Dowling; J. D. Garrett; D. L. Haynes; C. M. Jones; R. C. Juras; I. Y. Lee; M. J. Meigs; G. D. Mills; S. W. Mosko; B. A. Tatum; K. S. Toth

1991-01-01

79

Pinched relativistic electron beams and collective acceleration of ions  

Microsoft Academic Search

The collective acceleration of ions by a pinched relativistic electron beam is discussed. Two areas of relativistic electron beam research were investigated, electron beam pinch in the diode and the ion acceleration in an evacuated drift chamber. A 550 keV electron beam with peak current of 55 kA and of 50 nanoseconds duration, was produced in a high voltage diode,

V. Serlin

1979-01-01

80

The beam business: Accelerators in industry  

SciTech Connect

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

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

2011-06-15

81

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

82

Technical Challenges and Scientific Payoffs of Muon BeamAccelerators for Particle Physics  

SciTech Connect

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

Zisman, Michael S.

2007-09-25

83

Design of the beam delivery system for the international linear collider  

Microsoft Academic Search

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

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

2007-01-01

84

Method and apparatus for varying accelerator beam output energy  

DOEpatents

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

Young, Lloyd M. (Los Alamos, NM)

1998-01-01

85

Ion Colliders  

NASA Astrophysics Data System (ADS)

High energy ion colliders are large research tools in nuclear physics for studying the quark-gluon-plasma (QGP). The collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead, and uranium. Asymmetric collision combinations (such as protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders: the Relativistic Heavy Ion Collider (RHIC) at BNL and the Large Hadron Collider (LHC) at CERN.

Fischer, Wolfram; Jowett, John M.

2015-02-01

86

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

87

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

NASA Astrophysics Data System (ADS)

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

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

1999-06-01

88

Characterisation of electron beams from laser-driven particle accelerators  

SciTech Connect

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

Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A. [Physics Department, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2012-12-21

89

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

90

SINGLE CRYSTAL NIOBIUM TUBES FOR PARTICLE COLLIDERS ACCELERATOR CAVITIES  

SciTech Connect

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

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

2013-02-28

91

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

92

A plasma wakefield acceleration experiment using CLARA beam  

NASA Astrophysics Data System (ADS)

We propose a Plasma Accelerator Research Station (PARS) based at proposed FEL test facility CLARA (Compact Linear Accelerator for Research and Applications) at Daresbury Laboratory. The idea is to use the relativistic electron beam from CLARA, to investigate some key issues in electron beam transport and in electron beam driven plasma wakefield acceleration, e.g. high gradient plasma wakefield excitation driven by a relativistic electron bunch, two bunch experiment for CLARA beam energy doubling, high transformer ratio, long bunch self-modulation and some other advanced beam dynamics issues. This paper presents the feasibility studies of electron beam transport to meet the requirements for beam driven wakefield acceleration and presents the plasma wakefield simulation results based on CLARA beam parameters. Other possible experiments which can be conducted at the PARS beam line are also discussed.

Xia, G.; Angal-Kalinin, D.; Clarke, J.; Smith, J.; Cormier-Michel, E.; Jones, J.; Williams, P. H.; Mckenzie, J. W.; Militsyn, B. L.; Hanahoe, K.; Mete, O.; Aimidula, A.; Welsch, C. P.

2014-03-01

93

Beam Dynamics Studies for a Laser Acceleration Experiment  

SciTech Connect

The NLC Test Accelerator (NLCTA) at SLAC was built to address various beam dynamics issues for the Next Linear Collider. An S-Band RF gun is being installed together with a large-angle extraction line at 60 MeV followed by a matching section, buncher and final focus for the laser acceleration experiment, E163. The laser-electron interaction area is followed by a broad range, high resolution spectrometer (HES) for electron bunch analysis. Another spectrometer at 6 MeV will be used for analysis of bunch charges up to 1 nC. Emittance compensating solenoids and the low energy spectrometer (LES) will be used to tune for best operating point and match to the linac. Optical symmetries in the design of the 25.5{sup o} extraction line provide 1:1 phase space transfer without use of sextupoles for a large, 6D phase space volume and range of input conditions. Design techniques, tolerances, tuning sensitivities and orthogonal knobs are discussed.

Colby, e.; Noble, R.; Palmer, D.; Siemann, R.; Spencer, J

2005-05-17

94

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

95

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

96

Pinched Relativistic Electron Beams and Collective Acceleration of Ions  

Microsoft Academic Search

This work discusses the collective acceleration of ions by a pinched relativistic electron beam. Two areas of relativistic electron beam research are investigated, electron beam pinch in the diode and the ion acceleration in an evacuated drift-chamber. A 550 keV electron beam with peak current of 55 kA and of 50 nanoseconds duration, was produced in a high-voltage diode, designed

Victor Serlin

1979-01-01

97

Estimation of electron-cloud effect on NICA collider  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

98

DARHT II ACCELERATOR BEAM POSITION MONITOR PERFORMANCE ANALYSIS*  

E-print Network

Accurate and reliable beam position measurements are required to commission and operate the DARHT II Accelerator. The Beam Position Monitor (BPM) system developed for use on the DARHT II accelerator consists of 31 electro-magnetic detector assemblies, a computer network based data acquisition

unknown authors

99

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

100

Beam-driven acceleration in ultra-dense plasma media  

NASA Astrophysics Data System (ADS)

Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 × 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers ˜20% higher acceleration gradient by enlarging the channel radius (r) from 0.2 ?p to 0.6 ?p in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g., nanotubes) of high electron plasma density.

Shin, Young-Min

2014-09-01

101

ONE GEV BEAM ACCELERATION IN A ONE METER LONG  

E-print Network

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

102

Staging Laser Plasma Accelerators for Increased Beam Energy  

E-print Network

Staging Laser Plasma Accelerators for Increased Beam Energy D. Panasenko, A. J. Shu, C. B., Berkeley, California 94720, USA Abstract. Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies

Geddes, Cameron Guy Robinson

103

Beam experiments on the Pulse Line Ion Accelerator  

Microsoft Academic Search

Beam experiments on a new accelerator concept called the Pulse Line Ion Accelerator (PLIA) have demonstrated the ability to accelerate and compress ion bunches. Charging the PLIA to its full potential is limited by a vacuum surface flashover. Discharge issues have been evaluated for possible solutions. A numerical model has been developed to investigate the breakdown phenomena. Experimental results and

J. E. Coleman; A. Friedman; W. L. Waldron; F. M. Bieniosek; R. J. Briggs; D. P. Grote; E. Henestroza; P. K. Roy; P. A. Seidl; S. S. Yu

2007-01-01

104

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

105

ACE3P Computations of 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 novel two-beam accelerator concept envisions rf power transfer to the accelerating structures from a separate high-current decelerator beam line consisting of power extraction and transfer structures (PETS). It is critical to numerically verify the fundamental and higher-order mode properties in and between the two beam lines with high accuracy and confidence. To solve these large-scale problems, SLAC's parallel finite element electromagnetic code suite ACE3P is employed. Using curvilinear conformal meshes and higher-order finite element vector basis functions, unprecedented accuracy and computational efficiency are achieved, enabling high-fidelity modeling of complex detuned structures such as the CLIC TD24 accelerating structure. In this paper, time-domain simulations of wakefield coupling effects in the combined system of PETS and the TD24 structures are presented. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel CLIC two-beam accelerator scheme.

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

2010-10-27

106

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

107

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

108

Cryogenic Beam Screens for High-Energy Particle Accelerators  

E-print Network

Applied superconductivity has become a key enabling technology for high-energy particle accelerators, thus making them large helium cryogenic systems operating at very low temperature. The circulation of high-intensity particle beams in these machines generates energy deposition in the first wall through different processes. For thermodynamic efficiency, it is advisable to intercept these beam-induced heat loads, which may be large in comparison with cryostat heat in-leaks, at higher temperature than that of the superconducting magnets of the accelerator, by means of beam screens located in the magnet apertures. Beam screens may also be used as part of the ultra-high vacuum system of the accelerator, by sheltering the gas molecules cryopumped on the beam pipe from impinging radiation and thus avoiding pressure runaway. Space being extremely tight in the magnet apertures, cooling of the long, slender beam screens also raises substantial problems in cryogenic heat transfer and fluid flow. We present sizing rule...

Baglin, V; Tavian, L; van Weelderen, R

2013-01-01

109

Accelerating Airy beams with non-parabolic trajectories  

NASA Astrophysics Data System (ADS)

A class of Airy accelerating beams with non-parabolic trajectories are derived by means of a novel application of a conformal transformation originally due to Bateman. It is also shown that the salient features of these beams are very simply incorporated in a solution which is derived by applying a conventional conformal transformation together with a Galilean translation to the basic accelerating Airy beam solution of the two-dimensional paraxial equation. Motivation for the non-parabolic beam trajectories is provided and the effects of finite-energy requirements are discussed.

Besieris, Ioannis M.; Shaarawi, Amr M.

2014-11-01

110

Numerical Simulations of Transverse Beam Diffusion Enhancement by the Use of Electron Lens in the Tevatron Collider  

SciTech Connect

Transverse beam diffusion for the Tevatron machine has been calculated using the Lifetrac code. The following effects were included: random noise (representing residual gas scattering, voltage noise in the accelerating cavities) lattice nonlinearities and beam-beam interactions. The time evolution of particle distributions with different initial amplitudes in Hamiltonian action has been simulated for 6 million turns, corresponding to a time of about 2 minutes. For each particle distribution, several cases have been considered: a single beam in storage ring mode, the collider case and the effects of a hollow electron beam collimator. The diffusion coefficient for some representative points in the amplitude space has been calculated by fitting the time evolution of delta-like particle distributions using the diffusion equation, for different machine conditions. The results confirm a strong efficiency of the electron lens as an halo diffusive enhancer, leading to diffusion coefficients which are at least a factor 10K higher than the values obtained for the collision case. This result is confirmed by the Frequency Map Analysis, which shows a clear intensification of resonance lines for particle amplitudes larger than the electron lens inner radius. If compared with past experiments, the simulations successfully reproduce the diffusion coefficients for the beam core, but still present a large discrepancy for halo particles, still under investigation.

Previtali, V.; Stancari, G.; Valishev, A.; /Fermilab; Shatilov, D.N.; /Novosibirsk, IYF

2012-05-01

111

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,

2006-05-10

112

Progress Towards Doubling the Beam Power at Fermilab's Accelerator Complex  

SciTech Connect

After a 14 month shutdown accelerator modifications and upgrades are in place to allow us doubling of the Main Injector beam power. We will discuss the past MI high power operation and the current progress towards doubling the power.

Kourbanis, ioanis

2014-06-01

113

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

114

Advanced Surface Polishing For Accelerator Technology Using Ion Beams  

Microsoft Academic Search

A gas cluster ion beam (GCIB) technology was successfully applied to surface treatment of Cu, stainless steel, Ti, and Nb samples and to Nb rf-cavities by using accelerated cluster ion beams of Ar, O2 and combinations of them, with accelerating voltages up to 35 kV. DC field emission (dark current) measurements and electron microscopy were used to investigate metal surfaces

Z. Insepov; Jim Norem; A. Hassanein; A. T. Wu

2009-01-01

115

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

116

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

117

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

118

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

119

KT McDonald Proton Accelerator Workshop Jan 13, 2012 1 Target-System Challenges at a Muon Collider  

E-print Network

) cavities (in magnetic field for cooling) o presently untested ionization cooling technique o fast/Muon Collider. Severe materials issues for target AND beam dump. · Radiation Damage. · Melting. · Cracking (due every pulse. Proton beam readily tilted with respect to magnetic axis. Beam dump (mercury pool) out

McDonald, Kirk

120

Beam experiments on the Pulse Line Ion Accelerator  

NASA Astrophysics Data System (ADS)

Beam experiments on a new accelerator concept called the Pulse Line Ion Accelerator (PLIA) have demonstrated the ability to accelerate and compress ion bunches. Charging the PLIA to its full potential is limited by a vacuum surface flashover. Discharge issues have been evaluated for possible solutions. A numerical model has been developed to investigate the breakdown phenomena. Experimental results and possible solutions for the elimination of the discharge are described.

Coleman, J. E.; Friedman, A.; Waldron, W. L.; Bieniosek, F. M.; Briggs, R. J.; Grote, D. P.; Henestroza, E.; Roy, P. K.; Seidl, P. A.; Yu, S. S.

2007-07-01

121

Cavity beam position monitor system for the Accelerator Test Facility 2  

SciTech Connect

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

Kim, Y.I.; /Kyungpook Natl. U.; Ainsworth, R.; /Royal Holloway, U. of London; Aryshev, A.; /KEK, Tsukuba; Boogert, S.T.; Boorman, G.; /Royal Holloway, U. of London; Frisch, J.; /SLAC; Heo, A.; /Kyungpook Natl. U.; Honda, Y.; /KEK, Tsukuba; Hwang, W.H.; Huang, J.Y.; /Pohang Accelerator Lab.; Kim, E-S.; /Kyungpook Natl. U. /Pohang Accelerator Lab. /Royal Holloway, U. of London /KEK, Tsukuba

2012-04-02

122

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

123

Accelerators (4/5)  

ScienceCinema

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

None

2011-10-06

124

Accelerators (3/5)  

ScienceCinema

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

None

2011-10-06

125

Accelerators (5/5)  

ScienceCinema

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

None

2011-10-06

126

Tungsten Powder as an accelerator target & InBeam Testing  

E-print Network

1 Tungsten Powder as an accelerator target & InBeam Testing Ottone Caretta, Peter Loveridge 2. Moving Solid Tungsten Bars + studies on dynamic stress and strain-rate effects published beam parameters 3. Tungsten Powder + Pneumatic conveyance of powder demonstrated - wear of parts

McDonald, Kirk

127

Production of accelerating quad Airy beams and their optical characteristics.  

PubMed

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

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

2014-06-16

128

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

129

High transformer ratio drive beams for wakefield accelerator studies  

SciTech Connect

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

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

2012-12-21

130

Production and commissioning of a large prototype Digital Hadron Calorimeter for future colliding beam experiments  

Microsoft Academic Search

A new detector technology is being developed for future colliding beam experiments that is based on the use of fine-grained calorimetry, to optimize the use of Particle Flow Algorithms (PFAs) in measuring hadronic jets. Instead of traditional tower geometry and energy summation from many sampling layers, the new approach measures energy deposition in 1 cm2 cells on each sampling layer

A. Baumbaugh; B. Bilki; J. Butler; T. Cundiff; L. Dal Monte; P. De Lurgio; G. Drake; K. Francis; W. Haberichter; E. Hazen; J. Hoff; S. Holm; A. Kreps; J. Repond; J. Schlereth; J. Smith; D. Trojand; S. Wu; L. Xia; Q. Zhang

2011-01-01

131

Beam dump problem and neutrino factory based on an e+e- linear collider  

NASA Astrophysics Data System (ADS)

After a collision at the main interaction point the beam of an e+e- Linear Collider can be utilized to construct a neutrino factory with exceptional parameters. We also briefly discuss possible applications of some elements of the proposed scheme to standard fixed target experiments and new experiments with ?? N interactions.

Ginzburg, I. F.

2015-02-01

132

Operation of the CDF Silicon Vertex Detector with colliding beams at Fermilab  

SciTech Connect

In this paper we briefly describe the main features of the CDF Silicon Vertex Detector (SVX) and discuss its performance during actual colliding beam operation at the Fermilab Tevatron. Details on S/N ratio, alignment, resolution and efficiency are given.

Bedeschi, F.; Bolognesi, V.; Dell`Agnello, S.; Galeotti, S.; Grieco, G.; Mariotti, M.; Menzione, A.; Punzi, G.; Raffaelli, F.; Ristori, L.; Tartarelli, F.; Turini, N.; Wenzel, H.; Zetti, F. [Scuola Normale Superiore, Pisa (Italy); Bailey, M.W.; Garfinkel, A.F.; Kruse, M.C.; Shaw, N.M. [Purdue Univ., Lafayette, IN (United States); Carithers, W.C.; Ely, R.; Haber, C.; Holland, S.; Kleinfelder, S.; Merrick, T.; Schneider, O.; Wester, W.; Wong, M.; Yao, W. [Lawrence Berkeley Lab., CA (United States); Carter, H.; Flaugher, B.; Nelson, C.; Segler, S.; Shaw, T.; Tkaczyk, S.; Turner, K.; Wesson, T.R. [Fermi National Accelerator Lab., Batavia, IL (United States); Barnett, B.; Boswell, C.; Skarha, J.; Snider, F.D.; Spies, A.; Tseng, J.; Vejcik, S. [Johns Hopkins Univ., Baltimore, MD (United States); Amidei, D.; Derwent, P.F.; Song, T.Y.; Dunn, A. [Michigan Univ., Ann Arbor, MI (United States); Gold, M.; Matthews, J.; Bacchetta, N. [New Mexico Univ., Albuquerque, NM (United States); Azzi, P.; Bisello, D.; Busetto, G.; Castro, A.; Loreti, M.; Pescara, L. [Padova Univ. (Italy); Tipton, P.; Watts, G. [Rochester Univ., NY (United States)

1992-10-01

133

Turn-By Beam Extraction during Acceleration in a Synchrotron  

NASA Astrophysics Data System (ADS)

A synchrotron to accelerate protons or carbon ions for medical applications is being designed at Brookhaven National Laboratory (BNL). Single beam bunches with maximum beam energy of 1.18 GeV and 400 MeV/u for protons and carbon ions respectively will be extracted from the synchrotron at 15 Hz. For protons, the maximum required energy for irradiating a tumor is ˜206 MeV. A pencil-like proton beam containing ˜5.4×107 p/bunch delivers a therapeutic dose of 2.5 Gy in ˜1.5 minutes to treat a tumor of 1 liter volume. It will take ˜80 minutes with bunches containing 4.5×104 ions/bunch to deliver the same dose of 2.5 Gy with a 400 MeV/u pencil-like carbon beam. This extended treatment time when using carbon ions is not acceptable. In addition, the synchrotron cannot be controlled with a beam bunch containing such a low number of carbon ions. To overcome these two problems of the extended treatment time and the low bunch intensity required for the treatment when carbon ions are used, we have devised a method to “peel” the required 4.5×104 carbon-ions/bunch from the accelerating carbon beam bunch containing ˜108 ions/bunch and deliver them to the tumor on a “turn-by-turn” basis. Unlike other methods of beam extraction from a synchrotron, such as resonance extraction, this method does not allow for any beam losses during the extraction and the carbon beam can be peeled off in less than 15 ms during the acceleration or deceleration cycle of the synchrotron. Thus, this turn-by-turn beam extraction method provides beam with variable energy and precisely controlled beam current during the 30 ms acceleration or deceleration time.

Tsoupas, Nicholaos; Trbojevic, Dejan

2014-02-01

134

Relativistic electron-beam propagation in vacuum with ion acceleration  

SciTech Connect

A self-pinched relativistic electron beam is injected through a thin foil into vacuum with no externally applied magnetic field. The beam is observed to propagate at currents well above the space-charge-limiting current (approx.3 kA) but limited to the Alfven current (approx.30 kA). Propagation results from charge neutralization of the beam by ions accelerated out of the anode plasma as confirmed by various ion diagnostics. Ions are collectively accelerated to greater than the electron energy. The experimental results are in qualitative agreement with a one-dimensional time-dependent computer simulation.

Taylor, P.L.

1980-01-01

135

The Brookhaven Accelerator Test Facility laser linac beam line  

SciTech Connect

We report here the low emittance beam transport line for laser acceleration experiments at the Brookhaven Accelerator Test Facility (ATF). In order to preserve the low emittance ({approximately} 10{sup -10} m-rad) 50 MeV electron beam, great care has to be paid to the higher-order effects. The low-emittance transport line consists of two parts; the first part performs and emittance selection, and the other part provides the possibility of energy selection and beam transport to the experimental area. 7 refs., 5 figs., 7 tabs.

Wang, Xijie (Brookhaven National Lab., Upton, NY (USA) California Univ., Los Angeles, CA (USA). Center for Advanced Accelerators Physics); Kirk, H.G. (Brookhaven National Lab., Upton, NY (USA))

1989-09-26

136

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

137

Challenges in plasma and laser wakefield accelerated beams diagnostic  

NASA Astrophysics Data System (ADS)

The new frontier in the particle beam accelerator is the so called plasma acceleration. Using the strong electric field inside a plasma it is possible to achieve accelerating gradients in the order of magnitude larger with respect to the actual technologies. Different schemes have been proposed and several already tested, producing beams of energy of several GeV. Mainly two approaches are followed: either the beam is directly produced by the interaction of a TW/PW class laser with a gas jet or a preexisting particle beam is accelerated in a plasma channel. In both cases a precise determination of the emerging beam parameters is mandatory for the fine tuning of the devices. The measurement of these parameters, in particular the emittance, is not trivial, mainly due to the large energy spread and to the tight focusing of these beams or to the background noise produced in the plasma channel. We show the problems related to the diagnostic of this kind of beams and the proposed or already realized solutions.

Cianchi, A.; Anania, M. P.; Bellaveglia, M.; Castellano, M.; Chiadroni, E.; Ferrario, M.; Gatti, G.; Marchetti, B.; Mostacci, A.; Pompili, R.; Ronsivalle, C.; Rossi, A. R.; Serafini, L.

2013-08-01

138

Beam brilliance investigation of high current ion beams at GSI heavy ion accelerator facility  

SciTech Connect

In this work the emittance measurements of high current Ta-beam provided by VARIS (Vacuum Arc Ion Source) ion source are presented. Beam brilliance as a function of beam aperture at various extraction conditions is investigated. Influence of electrostatic ion beam compression in post acceleration gap on the beam quality is discussed. Use of different extraction systems (single aperture, 7 holes, and 13 holes) in order to achieve more peaked beam core is considered. The possible ways to increase the beam brilliance are discussed.

Adonin, A. A., E-mail: a.adonin@gsi.de; Hollinger, R. [Linac and Operations/Ion Sources, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany)] [Linac and Operations/Ion Sources, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany)

2014-02-15

139

Supplementary acceleration of intense beams of negative hydrogen ions  

SciTech Connect

Experiments on the acceleration of negative hydrogen ions are reported. The ions are produced by charge exchange in sodium vapor. They are accelerated from an energy 3--10 keV, which is the optimum energy for charge exchange, to 80 keV. The experimental results show that the breakdown events which occur between the electrodes as the beam passes can be suppressed by heating the supplementary acceleration system to 120/sup 0/ C. The results also show that the accompanying electron fluxes can also be successfully suppressed by means of a plasma lens. The maximum accelerated current reached was 4 A.

Krylov, A.I.; Kuznetsov, V.V.; Semashko, N.N.; Firsov, P.S.

1987-08-01

140

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

SciTech Connect

Halo formation and control in space-charge-dominated electron and ion beams are investigated in parameter regimes relevant to the development of high-power microwave (HPM) sources and high-intensity electron and ion linear accelerators. In particular, a mechanism for electron beam halo formation is identified in high-power periodic permanent magnet (PPM) focusing klystron amplifiers. It is found in self-consistent simulations that large-amplitude current oscillations induce mismatched beam envelope oscillations and electron beam halo formation. Qualitative agreement is found between simulations and the 50 MW 11.4 GHz PPM focusing klystron experiment at Stanford Linear Accelerator Center (SLAC) (D. Sprehn, G. Caryotakis, E. Jongewaard, and R. M. Phillips, ''Periodic permanent magnetic development for linear collider X-band klystrons,'' Proceedings of the XIXth International Linac Conference, Argonne National Laboratory Report ANL-98/28, 1998, p. 689). Moreover, a new class of cold-fluid corkscrewing elliptic beam equilibria is discovered for ultrahigh-brightness, space-charge dominated electron or ion beam propagation through a linear focusing channel consisting of uniform solenoidal magnetic focusing fields, periodic solenoidal magnetic focusing fields, and/or alternating-gradient quadrupole magnetic focusing fields in an arbitrary arrangement including field tapering. As an important application of such new cold-fluid corkscrewing elliptic beam equilibria, a technique is developed and demonstrated for controlling of halo formation and beam hollowing in a rms-matched ultrahigh-brightness ion beam as it is injected from an axisymmetric Pierce diode into an alternating-gradient magnetic quadrupole focusing channel. (c) 2000 American Institute of Physics.

Chen, C. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Pakter, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2000-05-01

141

High efficiency beam splitting for H/sup -/ accelerators  

SciTech Connect

Beam splitting for high energy accelerators has typically involved a significant loss of beam and radiation. This paper reports on a new method of splitting beams for H/sup -/ accelerators. This technique uses a high intensity flash of light to strip a fraction of the H/sup -/ beam to H/sup 0/ which are then easily separated by a small bending magnet. A system using a 900-watt (average electrical power) flashlamp and a highly efficient collector will provide 10/sup -3/ to 10/sup -2/ splitting of a 50 MeV H/sup -/ beam. Results on the operation and comparisons with stripping cross sections are presented. Also discussed is the possibility for developing this system to yield a higher stripping fraction.

Kramer, S.L.; Stipp, V.; Krieger, C.; Madsen, J.

1985-01-01

142

Characterization of the PEP-II Colliding-Beam Phase Space by the Boost Method  

SciTech Connect

We present a novel approach to characterize the colliding-beam phase space at the interaction point of the energy-asymmetric PEP-II B-Factory. The method exploits the fact that the transverse-boost distribution of e{sup +}e{sup -} {yields} {mu}{sup +}{mu}{sup -} events reconstructed in the BABAR detector reflects that of the colliding electrons and positrons. The mean boost direction, when combined with the measured orientation of the luminous ellipsoid, determines the e{sup +}-e{sup -} crossing angles. The average angular spread of the transverse boost vector provides an accurate measure of the angular divergence of the incoming high-energy beam, confirming the presence of a sizeable dynamic-{beta} effect. The longitudinal and transverse dependence of the boost angular spread also allow to extract from the continuously-monitored distributions detailed information about the emittances and IP {beta}-functions of both beams during high-luminosity operation.

Weaver, M.; /SLAC; Kozanecki, W.; /DAPNIA, Saclay; Viaud, B.; /Montreal U.

2006-07-19

143

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

144

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

145

Beam-driven acceleration in ultra-dense plasma media  

SciTech Connect

Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 10{sup 25?}m{sup ?3} and 1.6?×?10{sup 28?}m{sup ?3} plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers ?20% higher acceleration gradient by enlarging the channel radius (r) from 0.2 ?{sub p} to 0.6 ?{sub p} in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g., nanotubes) of high electron plasma density.

Shin, Young-Min [Department of Physics, Northern Illinois University, Dekalb, Illinois 60115 (United States); Accelerator Physics Center (APC), Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510 (United States)

2014-09-15

146

ALPI Setup as the SPES Accelerator of Exotic Beams  

NASA Astrophysics Data System (ADS)

The SPES (Selective Production of Exotic Species) project for a national exotic beam facility in Legnaro includes pivotal upgrades of the existing superconducting linac ALPI (Acceleratore Lineare Per Ioni), to make it appropriate as the RIB (Radioactive Ion Beam) accelerator. The new injector, consisting of an Electron Cyclotron Resonance (ECR)-type charge breeder and a radiofrequency quadrupole (RFQ), will be described. Upgrade measures in ALPI to improve beam transmission and final energy, and handle low-intensity RIB will be explained, with the aim of increasing transmission to T > 90%, Ef by ~ 20%, reaching 10 MeV/u for the reference beam 132Sn.

Bisoffi, G.; Bassato, G.; Battistella, A.; Bermudez, J.; Bortolato, D.; Canella, S.; Chalykh, B.; Comunian, M.; Facco, A.; Fagotti, E.; Galatà, A.; Giacchini, M.; Gramegna, F.; Lamy, T.; Modanese, P.; Palmieri, A.; Pengo, R.; Pisent, A.; Poggi, M.; Porcellato, A.; Roncolato, C.; Scarpa, D.

2014-03-01

147

Data handling facility for the Sandia Particle Beam Fusion Accelerator  

SciTech Connect

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

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

1980-01-01

148

Beam manipulation techniques, nonlinear beam dynamics, and space charge effect in high energy high power accelerators  

SciTech Connect

We had carried out a design of an ultimate storage ring with beam emittance less than 10 picometer for the feasibility of coherent light source at X-ray wavelength. The accelerator has an inherent small dynamic aperture. We study method to improve the dynamic aperture and collective instability for an ultimate storage ring. Beam measurement and accelerator modeling are an integral part of accelerator physics. We develop the independent component analysis (ICA) and the orbit response matrix method for improving accelerator reliability and performance. In collaboration with scientists in National Laboratories, we also carry out experimental and theoretical studies on beam dynamics. Our proposed research topics are relevant to nuclear and particle physics using high brightness particle and photon beams.

Lee, S. Y.

2014-04-07

149

Beam intensity increases at the intense pulsed neutron source accelerator  

SciTech Connect

The Intense Pulsed Neutron Source (IPNS) accelerator system has managed a 40% increase in time average beam current over the last two years. Currents of up to 15.6..mu..A (3.25 x 10/sup 12/ protons at 30 Hz) have been successfully accelerated and cleanly extracted. Our high current operation demands low loss beam handling to permit hands-on maintenance. Synchrotron beam handling efficiencies of 90% are routine. A new H/sup -/ ion source which was installed in March of 1983 offered the opportunity to get above 8 ..mu..A but an instability caused unacceptable losses when attempting to operate at 10 ..mu..A and above. Simple techniques to control the instabilities were introduced and have worked well. These techniques are discussed below. Other improvements in the regulation of various power supplies have provided greatly improved low energy orbit stability and contributed substantially to the increased beam current.

Potts, C.; Brumwell, F.; Norem, J.; Rauchas, A.; Stipp, V.; Volk, G.

1985-01-01

150

Iron beam acceleration using direct plasma injection scheme  

SciTech Connect

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

Okamura, M., E-mail: okamura@bnl.gov [Brookhaven National Laboratory, Upton, New York 11973 (United States); RIKEN-BNL Research Center, Upton, New York 11973 (United States); Kanesue, T. [Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Brookhaven National Laboratory, Upton, New York 11973 (United States); Yamamoto, T. [Waseda University, Shinjuku, Tokyo 169-8555 (Japan)] [Waseda University, Shinjuku, Tokyo 169-8555 (Japan); Fuwa, Y. [Kyoto University, Uji, Kyoto 611-0011 (Japan) [Kyoto University, Uji, Kyoto 611-0011 (Japan); RIKEN, Wako, Saitama 351-0198 (Japan)

2014-02-15

151

Laser-driven shock acceleration of monoenergetic ion beams.  

PubMed

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

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

2012-11-21

152

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

SciTech Connect

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 study such accidents taking the Superconducting Supercollider complex as an example. Particle tracking, beam loss and energy deposition calculations were done using the realistic machine simulation with the Monte-Carlo codes MARS 12 and STRUCT. Protective measures for minimizing the damaging effects of prefire and misfire of injection and extraction kicker magnets are proposed here.

Drozhdin, A.; Mokhov, N.; Parker, B.

1994-02-01

153

Beam-breakup calculations for the DARHT accelerator  

Microsoft Academic Search

An induction line that will accelerate a 4-MeV, 3-kA beam of electrons to 16- to 20-MeV in 64 gaps is modeled. To suppress beam-breakup (BBU) instabilities induced by excitation of RF deflecting modes, the growth factor ? must be kept sufficiently small (e.g. <3). On prototype DARHT cavities, RF measurements have shown that the normally degenerate TM modes are split

Paul Allison; M. J. Burns; George J. Caporaso; A. G. Cole

1991-01-01

154

Physics of beam self-modulation in plasma wakefield accelerators  

E-print Network

The self-modulation instability is a key effect that makes possible the usage of nowadays proton beams as drivers for plasma wakefield acceleration. Development of the instability in uniform plasmas and in plasmas with a small density up-step is numerically studied with the focus at nonlinear stages of beam evolution. The step parameters providing the strongest established wakefield are found, and the mechanism of stable bunch train formation is identified.

Lotov, K V

2015-01-01

155

Fully vectorial accelerating diffraction-free Helmholtz beams.  

PubMed

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

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

2012-11-16

156

Beam Physics of Integrable Optics Test Accelerator at Fermilab  

SciTech Connect

Fermilab's Integrable Optics Test Accelerator (IOTA) is an electron storage ring designed for testing advanced accelerator physics concepts, including implementation of nonlinear integrable beam optics and experiments on optical stochastic cooling. The machine is currently under construction at the Advanced Superconducting Test Accelerator facility. In this report we present the goals and the current status of the project, and describe the details of machine design. In particular, we concentrate on numerical simulations setting the requirements on the design and supporting the choice of machine parameters.

Nagaitsev, S.; Valishev, A.; /Fermilab; Danilov, V.V.; /Oak Ridge; Shatilov, D.N.; /Novosibirsk, IYF

2012-05-01

157

Investigation of accelerated neutral atom beams created from gas cluster ion beams  

NASA Astrophysics Data System (ADS)

A new concept for ultra-shallow processing of surfaces known as accelerated neutral atom beam (ANAB) technique employs conversion of energetic gas cluster ions produced by the gas cluster ion beam (GCIB) method into intense collimated beams of coincident neutral gas atoms having controllable average energies from less than 10 eV per atom to beyond 100 eV per atom. A beam of accelerated gas cluster ions is first produced as is usual in GCIB, but conditions within the source ionizer and extraction regions are adjusted such that immediately after ionization and acceleration the clusters undergo collisions with non-ionized gas atoms. Energy transfer during these collisions causes the energetic cluster ions to release many of their constituent atoms. An electrostatic deflector is then used to eliminate charged species, leaving the released neutral atoms to still travel collectively at the same velocities they had as bonded components of their parent clusters. Upon target impact, the accelerated neutral atom beams produce effects similar to those normally associated with GCIB, but to shallower depths, with less surface damage and with superior subsurface interfaces. The paper discusses generation and characterization of the accelerated neutral atom beams, describes interactions of the beams with target surfaces, and presents examples of ongoing work on applications for biomedical devices.

Kirkpatrick, A.; Kirkpatrick, S.; Walsh, M.; Chau, S.; Mack, M.; Harrison, S.; Svrluga, R.; Khoury, J.

2013-07-01

158

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

159

Transition Radiation Detector in the D0 colliding beam experiment at Fermilab  

SciTech Connect

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

Piekarz, H.

1995-04-01

160

Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude  

DOEpatents

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

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

1995-01-01

161

Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude  

DOEpatents

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

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

1995-08-08

162

Physics design of linear accelerators for intense ion beams  

SciTech Connect

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

Wangler, T.P.

1988-01-01

163

Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators  

SciTech Connect

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

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

2008-01-28

164

Reactive accelerated cluster erosion (RACE) by ionized cluster beams  

NASA Astrophysics Data System (ADS)

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

Gspann, Jürgen

1996-05-01

165

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

166

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

167

Beam by design: Laser manipulation of electrons in modern accelerators  

NASA Astrophysics Data System (ADS)

Accelerator-based light sources such as storage rings and free-electron lasers use relativistic electron beams to produce intense radiation over a wide spectral range for fundamental research in physics, chemistry, materials science, biology, and medicine. More than a dozen such sources operate worldwide, and new sources are being built to deliver radiation that meets with the ever-increasing sophistication and depth of new research. Even so, conventional accelerator techniques often cannot keep pace with new demands and, thus, new approaches continue to emerge. In this article, a variety of recently developed and promising techniques that rely on lasers to manipulate and rearrange the electron distribution in order to tailor the properties of the radiation are reviewed. Basic theories of electron-laser interactions, techniques to create microstructures and nanostructures in electron beams, and techniques to produce radiation with customizable waveforms are reviewed. An overview of laser-based techniques for the generation of fully coherent x rays, mode-locked x-ray pulse trains, light with orbital angular momentum, and attosecond or even zeptosecond long coherent pulses in free-electron lasers is presented. Several methods to generate femtosecond pulses in storage rings are also discussed. Additionally, various schemes designed to enhance the performance of light sources through precision beam preparation including beam conditioning, laser heating, emittance exchange, and various laser-based diagnostics are described. Together these techniques represent a new emerging concept of "beam by design" in modern accelerators, which is the primary focus of this article.

Hemsing, Erik; Stupakov, Gennady; Xiang, Dao; Zholents, Alexander

2014-07-01

168

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

NASA Astrophysics Data System (ADS)

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

Li, Wentao; Liu, Jiansheng; Wang, Wentao; Chen, Qiang; Zhang, Hui; Tian, Ye; Zhang, Zhijun; Qi, Rong; Wang, Cheng; Leng, Yuxin; Li, Ruxin; Xu, Zhizhan

2013-11-01

169

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

170

SLAC linear collider conceptual design report  

SciTech Connect

The linear collider system is described in detail, including the transport system, the collider lattice, final focusing system, positron production, beam damping and compression, high current electron source, instrumentation and control, and the beam luminosity. The experimental facilities and the experimental uses are discussed along with the construction schedule and estimated costs. Appendices include a discussion of space charge effects in the linear accelerator, emittance growth in the collider, the final focus system, beam-beam instabilities and pinch effects, and detector backgrounds. (GHT)

Not Available

1980-06-01

171

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

172

ACCELERATOR RESEARCH STUDIES  

SciTech Connect

ACCELERATOR RESEARCH STUDIES Task A: Study of the Physics of Space-Charge Dominated Beams for Advanced Accelerator Applications Task B: Studies of High-Power Gyroklystrons and Application to Linear Colliders Task C: Theory and Simulation of the Physics Space-Charge Dominated Beams Annual Report for the Period June 1, 2003 to May 31, 2004

P.G. O'Shea, M. Reiser, V. L. Granatstein, W. Lawson, I. Haber, R. Kishek

2004-01-23

173

An Accelerated Collaboration Meets with Beaming Success  

SciTech Connect

Maintaining a smaller, aging U.S. nuclear weapons stockpile without underground nuclear testing requires the capability to verify and validate the complex computer calculations on which stockpile confidence is based. This capability, in turn, requires nonnuclear hydrodynamic tests (hydrotests) that can x-ray stages of the implosion process, providing freeze-frame photos of materials imploding at speeds of more than 16,000 kilometers per hour. The images will yield important information on shapes and densities of metals and other materials under the extreme pressures and temperatures generated by the detonation of high explosives. The Dual-Axis Radiographic Hydrodynamics Test (DARHT) Facility at Los Alamos national Laboratory is a two-arm x-ray imaging system that will provide such images, capturing the inner workings of a mock nuclear explosion with high resolution. Scientists compare the radiographic images with computer models, examine the differences, and refine the models to more accurately represent weapon behavior. One of DARHT's arms (now called DARHT-II) recently got a ''leg up'' through a collaboration of Lawrence Livermore and Los Alamos scientists, using a Livermore accelerator to test its subsystems and codes.

Hazi, A U

2007-02-09

174

A cascaded laser acceleration scheme for the generation of spectrally controlled proton beams  

E-print Network

We present a novel, cascaded acceleration scheme for the generation of spectrally controlled ion beams using a laser-based accelerator in a 'double-stage' setup. An MeV proton beam produced during a relativistic laser–plasma ...

Pfotenhauer, Sebastian Michael

175

Superconducting accelerating structures for very low velocity ion beams  

SciTech Connect

This paper presents designs for four types of very-low-velocity superconducting accelerating cavity capable of providing several MV of accelerating potential per cavity, and suitable for particle velocities in the range 0.006 < v/c < 0.06. Superconducting TEM-class cavities have been widely applied to CW acceleration of ion beams. SC linacs can be formed as an array of independently-phased cavities, enabling a variable velocity profile to maximize the output energy for each of a number of different ion species. Several laboratories in the US and Europe are planning exotic beam facilities based on SC linacs. The cavity designs presented here are intended for the front-end of such linacs, particularly for the post-acceleration of rare isotopes of low charge state. Several types of SC cavities have been developed recently to cover particle velocities above 0.06c. Superconducting four-gap quarter-wave resonators for velocities 0.008 < {beta} = v/c < 0.05 were developed about two decades ago and have been successfully operated at the ATLAS SC linac at Argonne National Laboratory. Since that time, progress in simulation tools, cavity fabrication and processing have increased SC cavity gradients by a factor of 3-4. This paper applies these tools to optimize the design of a four-gap quarter-wave resonator for exotic beam facilities and other low-velocity applications.

Xu, J.; Shepard, K.W.; Ostroumov, P.N.; Fuerst, J.D.; Waldschmidt, G.; /Argonne; Gonin, I.V.; /Fermilab

2008-01-01

176

Electron beam dynamics in the DARHT-II linear induction accelerator  

Microsoft Academic Search

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

Carl A Ekdahl; Epifanio O Abeyta; Paul Aragon; Rita Archuleta; Gerald Cook; Dale Dalmas; Kevin Esquibel; Robert A Gallegos; Robert Garnett; James F Harrison; Jeffrey B Johnson; Edward B Jacquez; Brian T Mccuistian; Nicholas A Montoya; Subrata Nath; Kurt Nielsen; David Oro; Benjamin Prichard; Lawrence Rowton; Manolito Sanchez; Raymond Scarpetti; Martin M Schauer; Gerald Seitz; Martin Schulze; Howard A Bender; William B Broste; Carl A Carlson; Daniel K Frayer; Douglas E Johnson; C Y Tom; C Trainham; John Williams; Thomas Genoni; Thomas Hughes; Carsten Toma

2008-01-01

177

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

178

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

179

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

180

Electron capture acceleration channel in a slit laser beam  

SciTech Connect

Using numerical simulations, the authors find that the electrons can be captured and accelerated to high energies (GeV) in a slit laser beam with an intensity of I{lambda}{sup 2}{approx}10{sup 20} W/cm{sup 2} {mu}m{sup 2}, where {lambda} is the laser wavelength in units of {mu}m. The range of the optimum incident energy is very wide, even up to GeV. These results are of interest for experiments because the relatively low intensity can be achieved with present chirped pulse amplification technique and a wide range of incident energies means that a multistage acceleration is possible.

Wang, P. X.; Scheid, W.; Ho, Y. K. [Institute for Theoretical Physics, Justus-Liebig-University, Giessen (Germany); Institute of Modern Physics, Fudan University, Shanghai 200433 (China)

2007-03-12

181

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

182

ELIMED, future hadrontherapy applications of laser-accelerated beams  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

183

Heavy ion beam scanning system of DC-110 accelerator  

NASA Astrophysics Data System (ADS)

A heavy ion acceleration complex for industrial applications based on the DC-110 cyclotron has been developed at the Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research. It is planned to irradiate polymer films with a width of up to 600 mm at this complex. This paper presents a design of a system for scanning heavy ion beam which offers uniform film irradiation at a beam energy of up to 2.5 MeV/nucleon. The general concept of the two-channel scanning system and the design of the main deflecting magnets are described.

Gikal, B. N.; Gorbachev, E. V.; Lebedev, N. I.; Fateev, A. A.

2010-12-01

184

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

185

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

186

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

187

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

188

Advanced Surface Polishing For Accelerator Technology Using Ion Beams  

SciTech Connect

A gas cluster ion beam (GCIB) technology was successfully applied to surface treatment of Cu, stainless steel, Ti, and Nb samples and to Nb rf-cavities by using accelerated cluster ion beams of Ar, O{sub 2} and combinations of them, with accelerating voltages up to 35 kV. DC field emission (dark current) measurements and electron microscopy were used to investigate metal surfaces treated by GCIB. The experimental results showed that GCIB technique can significantly reduce the number of field emitters and can change the structure of the Nb oxide layer on the surface. The RF tests of the GCIB-treated Nb rf-cavities showed improvement of the quality factor Q at 4.5 K. The superconducting gap was also enhanced by using the oxygen GCIB irradiation exposure.

Insepov, Z.; Norem, J. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Hassanein, A. [Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States); Wu, A. T. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

2009-03-10

189

Advanced Surface Polishing for Accelerator Technology using Ion Beams  

SciTech Connect

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

Z. Insepov, Jim Norem, Andy Wu

2009-03-01

190

Beam by design: laser manipulation of electrons in modern accelerators  

E-print Network

Accelerator-based light sources such as storage rings and free-electron lasers use relativistic electron beams to produce intense radiation over a wide spectral range for fundamental research in physics, chemistry, materials science, biology and medicine. More than a dozen such sources operate worldwide, and new sources are being built to deliver radiation that meets with the ever increasing sophistication and depth of new research. Even so, conventional accelerator techniques often cannot keep pace with new demands and, thus, new approaches continue to emerge. In this article, we review a variety of recently developed and promising techniques that rely on lasers to manipulate and rearrange the electron distribution in order to tailor the properties of the radiation. Basic theories of electron-laser interactions, techniques to create micro- and nano-structures in electron beams, and techniques to produce radiation with customizable waveforms are reviewed. We overview laser-based techniques for the generation ...

Hemsing, Erik; Xiang, Dao; Zholents, Alexander

2014-01-01

191

Results of the SINGAP Neutral Beam Accelerator Experiment at JAEA  

SciTech Connect

IRFM (CEA Cadarache) and JAEA Naka have entered into a collaboration in order to test a SINGAP accelerator at the JAEA Megavolt Test Facility (MTF) at Naka, Japan. Whereas at the CEA testbed the acceleration current was limited to 0.1 A, at JAEA 0.5 A is available. This allows the acceleration of 15 H- beamlets in SINGAP to be tested and a direct comparison between SINGAP and MAMuG to be made. High-voltage conditioning in the SINGAP configuration has been quite slow, with 581 kV in vacuum achieved after 140 hours of conditioning. With 0.1 Pa of H2 gas present in the accelerator 787 kV could be achieved. The conditioning curve for MAMuG is 200 kV higher. SINGAP beam optics appears in agreement with calculation results. A beamlet divergence better than 5 mrad was obtained. SINGAP accelerates electrons to a higher energy than MAMuG. Measurements of the power intercepted on one of the electron dumps have been compared with EAMCC code calculations. Based on the experiments described here, electron production by a SINGAP accelerator scaled up to ITER size was estimated to be too high for comfort.

Esch, H. P. L. de; Svensson, L. [CEA Cadarache, IRFM, F-13108 St. Paul-lez-Durance (France); Inoue, T.; Taniguchi, M.; Umeda, N.; Kashiwagi, M. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 311-0193 (Japan); Fubiani, G. [Laboratoire Plasma et Conversion d'Energie (LAPLACE) Universite Paul Sabatier, Bt 3R2, 118 Route de Narbonne (France)

2009-03-12

192

Development of Virtual Accelerator Environment for Beam Diagnostics  

E-print Network

For the proper operation of Dalian Compact Light Source (DCLS) linac, measurement and control of the electron bunch is critical. In order to test control algorithms and high level physical applications, a virtual accelerator environment is constructed based on ELEGANT and SDDS toolkit. The required beam parameter measurement and orbit control tools are verified under this virtual environment. The design concept and current development status are presented.

Gu, Duan; Gu, Qiang; Huang, Dazhang; Zhao, Minghua

2014-01-01

193

Negative hydrogen ion source research and beam parameters for accelerators  

Microsoft Academic Search

H 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 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

Timofey V. Zolkin

2006-01-01

194

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

195

Superconducting accelerating structures for very low velocity ion beams.  

SciTech Connect

This paper presents designs for four types of very-low-velocity superconducting (SC) accelerating cavity capable of providing several MV of accelerating potential per cavity, and suitable for particle velocities in the range 0.006acceleration of ion beams. SC linacs can be formed as an array of independently phased cavities, enabling a variable velocity profile to maximize the output energy for each of a number of different ion species. Several laboratories in the U.S. and Europe are planning exotic beam facilities based on SC linacs. The cavity designs presented here are intended for the front end of such linacs, particularly for the postacceleration of rare isotopes of low charge state. Several types of SC cavities have been developed recently to cover particle velocities above 0.06c. Superconducting four-gap quarter-wave resonators for velocities 0.008<{beta}=v/c<0.05 were developed about two decades ago and have been successfully operated at the ATLAS SC linac at Argonne National Laboratory. Since that time, progress in simulation tools, cavity fabrication, and processing have increased SC cavity gradients by a factor of 3-4. This paper applies these tools to optimize the design of a four-gap quarter-wave resonator for exotic beam facilities and other low-velocity applications.

Xu, J.; Shepard, K. W.; Ostroumov, P. N.; Fuerst, J. D.; Waldschmidt, G.; Gonin, I. V.; FNAL

2008-03-01

196

Superconducting accelerating structures for very low velocity ion beams  

NASA Astrophysics Data System (ADS)

This paper presents designs for four types of very-low-velocity superconducting (SC) accelerating cavity capable of providing several MV of accelerating potential per cavity, and suitable for particle velocities in the range 0.006acceleration of ion beams. SC linacs can be formed as an array of independently phased cavities, enabling a variable velocity profile to maximize the output energy for each of a number of different ion species. Several laboratories in the U.S. and Europe are planning exotic beam facilities based on SC linacs. The cavity designs presented here are intended for the front end of such linacs, particularly for the postacceleration of rare isotopes of low charge state. Several types of SC cavities have been developed recently to cover particle velocities above 0.06c. Superconducting four-gap quarter-wave resonators for velocities 0.008beam facilities and other low-velocity applications.

Xu, J.; Shepard, K. W.; Ostroumov, P. N.; Fuerst, J. D.; Waldschmidt, G.; Gonin, I. V.

2008-03-01

197

On the possibilities of using edge detector algorithms for beam spot diagnostics of accelerator beams  

NASA Astrophysics Data System (ADS)

Diagnostics of accelerator beams using TV cameras to observe the beam spot is quite common. Several software algorithms like those based on the work of Sobel, Roberts, Prewitt, Marr-Hildreth, and Canny are applied to the captured image to yield a binary image. For the present purpose, the Canny algorithm is found to produce by far the best result and the data obtained is suggestive of further implementation in similar fields of research.

Lindblad, Th.; Johansson, F.; Källberg, A.; Lindsey, C. S.; Rosengård, U.; Székely, G.

1994-12-01

198

Uncovering beam position monitor noise at the Relativistic Heavy Ion Collider  

NASA Astrophysics Data System (ADS)

We apply the independent component analysis (ICA) algorithm to uncover intrinsic noise in the beam position monitor (BPM) system. Numerical simulations found that ICA is efficient in the BPM noise estimation. The ICA algorithm is applied to the turn-by-turn data at the Relativistic Heavy Ion Collider. We found the distribution of the BPM noise level, which is consistent with the Johnson-Nyquist thermal noise model. The ICA analysis of turn-by-turn data can be used in neuronetwork feasibility of monitoring a storage ring parasitically.

Shen, X.; Lee, S. Y.; Bai, M.

2015-01-01

199

Heavy ion beam-ionosphere interactions - Electron acceleration  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

200

Resolving EMI Issues To Optimize Accelerator Beam Diagnostic Performance  

SciTech Connect

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

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

2004-11-10

201

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

202

Search for magnetic fields in particle-accelerating colliding-wind binaries  

NASA Astrophysics Data System (ADS)

Context. Some colliding-wind massive binaries, called particle-accelerating colliding-wind binaries (PACWB), exhibit synchrotron radio emission, which is assumed to be generated by a stellar magnetic field. However, no measurement of magnetic fields in these stars has ever been performed. Aims: We aim at quantifying the possible stellar magnetic fields present in PACWB to provide constraints for models. Methods: We gathered 21 high-resolution spectropolarimetric observations of 9 PACWB available in the ESPaDOnS, Narval and HarpsPol archives. We analysed these observations with the least squares deconvolution method. We separated the binary spectral components when possible. Results: No magnetic signature is detected in any of the 9 PACWB stars and all longitudinal field measurements are compatible with 0 G. We derived the upper field strength of a possible field that could have remained hidden in the noise of the data. While the data are not very constraining for some stars, for several stars we could derive an upper limit of the polar field strength of the order of 200 G. Conclusions: We can therefore exclude the presence of strong or moderate stellar magnetic fields in PACWB, typical of the ones present in magnetic massive stars. Weak magnetic fields could however be present in these objects. These observational results provide the first quantitative constraints for future models of PACWB. Based on archival observations obtained at the Télescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique (CNRS) of France, at the Canada-France-Hawaii Telescope (CFHT) operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the CNRS of France, and the University of Hawaii, and at the European Southern Observatory (ESO), Chile.

Neiner, C.; Grunhut, J.; Leroy, B.; De Becker, M.; Rauw, G.

2015-03-01

203

Beam-induced Electron Loading Effects in High Pressure Cavities for a Muon Collider  

SciTech Connect

Ionization cooling is a critical building block for the realization of a muon collider. To suppress breakdown in the presence of the external magnetic field, an idea of using an RF cavity filled with high pressure hydrogen gas is being considered for the cooling channel design. One possible problem expected in the high pressure RF cavity is, however, the dissipation of significant RF power through the beam-induced electrons accumulated inside the cavity. To characterize this detrimental loading effect, we develop a simplified model that relates the electron density evolution and the observed pickup voltage signal in the cavity, with consideration of several key molecular processes such as the formation of the polyatomic molecules, recombination and attachment. This model is expected to be compared with the actual beam test of the cavity in the MuCool Test Area (MTA) of Fermilab.

Chung, M.; Tollestrup, A.; Jansson, A.; Yonehara, K.; /Fermilab; Insepov, Z.; /Argonne

2010-05-01

204

Contact fermion-Higgs interactions at an $e^+e^-$ collider with polarized beams  

E-print Network

We consider the possibility of new physics represented by contact interactions giving rise to interaction vertices of the form $e^+e^-Hf \\bar f$, where $f$ represents a charged lepton $\\ell$ or a (light) quark $q$, and $H$ the recently discovered Higgs boson. Such vertices would give contributions beyond the standard model to the Higgs production processes $e^+e^- \\to H\\ell^+\\ell^-$ and $e^+e^- \\to H q \\bar q$ at a future $e^+e^-$ collider. We write the most general form for these vertices allowed by Lorentz symmetry. Assuming that such contact interactions contribute in addition to the standard model production processes, where the final-state fermion pair comes from the decay of $Z$ boson, we obtain the differential cross section for the processes $e^+e^- \\to H\\ell^+\\ell^-$ and $e^+e^- \\to Hq\\bar q$ to linear order in the contact interactions. We propose several observables with differing CP and T properties which, if measured, can be used to constrain the couplings occurring in contact interaction vertices. We derive possible limits on these couplings that may be obtained at a collider with centre-of-mass energy of 500 GeV and an integrated luminosity of 500 fb$^{-1}$. We also carry out the analysis assuming that both electron positron beams can be longitudinally polarized, and find that the sensitivity can be greatly improved by a specific choice of the signs of the polarizations of the electron and positron beams.

Katri Huitu; Kumar Rao; Saurabh D. Rindani; Pankaj Sharma

2015-01-22

205

Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability  

NASA Astrophysics Data System (ADS)

Axial beam centroid and beam breakup (BBU) measurements were conducted on an 80 ns FWHM, intense relativistic electron bunch with an injected energy of 3.8 MV and current of 2.9 kA. The intense relativistic electron bunch is accelerated and transported through a nested solenoid and ferrite induction core lattice consisting of 64 elements, exiting the accelerator with a nominal energy of 19.8 MeV. The principal objective of these experiments is to quantify the coupling of the beam centroid motion to the BBU instability and validate the theory of this coupling for the first time. Time resolved centroid measurements indicate a reduction in the BBU amplitude, ???, of 19% and a reduction in the BBU growth rate (?) of 4% by reducing beam centroid misalignments ˜50% throughout the accelerator. An investigation into the contribution of the misaligned elements is made. An alignment algorithm is presented in addition to a qualitative comparison of experimental and calculated results which include axial beam centroid oscillations, BBU amplitude, and growth with different dipole steering.

Coleman, J. E.; Ekdahl, C. A.; Moir, D. C.; Sullivan, G. W.; Crawford, M. T.

2014-09-01

206

Performance of the Upgraded LHCf Calorimeter with Gd2SiO5 (GSO) Scintillators Tested by Accelerator Beams  

NASA Astrophysics Data System (ADS)

LHCf has reported energy spectra of forward photons and neutral pions at ?{s} = 900 GeV and 7 TeV proton-proton collisions measured at the Large Hadron Collider (LHC). Because the next operation in 2015 is expected under much higher radiation dose, we are upgrading the detectors, especially their scintillators, to be radiation harder. We report the results from the beam tests performed at the Heavy Ion Medical Accelerator in Chiba (HIMAC) in Japan for the basic properties of new sensors. We have confirmed that the new sensors meet our requirements at this stage.

Makino, Yuya

207

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

208

Relativistic electron beam acceleration by Compton scattering of extraordinary waves  

SciTech Connect

Relativistic transport equations, which demonstrate that relativistic and nonrelativistic particle acceleration along and across a magnetic field and the generation of an electric field transverse to the magnetic field, are induced by nonlinear wave-particle scattering (nonlinear Landau and cyclotron damping) of almost perpendicularly propagating electromagnetic waves in a relativistic magnetized plasma were derived from the relativistic Vlasov-Maxwell equations. The relativistic transport equations show that electromagnetic waves can accelerate particles in the k{sup ''} direction (k{sup ''}=k-k{sup '}). Simultaneously, an intense cross-field electric field, E{sub 0}=B{sub 0}xv{sub d}/c, is generated via the dynamo effect owing to perpendicular particle drift to satisfy the generalized Ohm's law, which means that this cross-field particle drift is identical to the ExB drift. On the basis of these equations, acceleration and heating of a relativistic electron beam due to nonlinear wave-particle scattering of electromagnetic waves in a magnetized plasma were investigated theoretically and numerically. Two electromagnetic waves interact nonlinearly with the relativistic electron beam, satisfying the resonance condition of {omega}{sub k}-{omega}{sub k{sup '}}-(k{sub perpendicular}-k{sub perpendicula=} r{sup '})v{sub d}-(k{sub parallel}-k{sub parallel}{sup '})v{sub b}{approx_equal}m{omega}{sub ce}, where v{sub b} and v{sub d} are the parallel and perpendicular velocities of the relativistic electron beam, respectively, and {omega}{sub ce} is the relativistic electron cyclotron frequency. The relativistic transport equations using the relativistic drifted Maxwellian momentum distribution function of the relativistic electron beam were derived and analyzed. It was verified numerically that extraordinary waves can accelerate the highly relativistic electron beam efficiently with {beta}m{sub e}c{sup 2} < or approx. 1 GeV, where {beta}=(1-v{sub b}{sup 2}/c{sup 2}){sup -1/2}.

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

2006-05-15

209

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

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

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

2011-06-27

210

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

211

The Next Linear Collider machine protection system  

Microsoft Academic Search

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

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

1999-01-01

212

The Next Linear Collider Machine Protection System  

Microsoft Academic Search

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

1999-01-01

213

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

214

DEVELOPMENT OF MULTI-MEGA WATT NEGATIVE ION SOURCES AND ACCELERATORS FOR NEUTRAL BEAM INJECTORS  

Microsoft Academic Search

High energy and high power negative ion sources and accelerators have been developed for neutral beam (NB) injectors of futu re fusion machines such as International Thermonuclear Experimental Reactor (ITER). Using a 5 -stage electrostatic accelerator, negative ion beam has been successfully accelerated up to the energy of 1 MeV, which is the required energy for ITER. Powerful negative ion

M. Hanada; N. Akino; N. Ebisawa; Y. Fujiwara; A. Honda; T. Itoh; K. Kawai; M. Kazawa; M. Kuriyama; K. Miyamoto; K. Mogaki; T. Ohga; Y. Okumura; H. Oohara; K. Oomori; K. Usui; K. Watanabe

215

Physics of a repetitively pulsed 10 kAmp electron beam accelerator  

SciTech Connect

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

Fessenden, T.J.; Atchison, W.A.; Birx, D.L.; Briggs, R.J.; Clark, J.C.; Hester, R.E.; Neil, V.K.; Paul, A.C.; Rogers, D. Jr.; Struve, K.W.

1981-01-01

216

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

217

Beam dynamics activities at the Thomas Jefferson National Accelerator Facility (Jefferson Lab)  

SciTech Connect

The Thomas Jefferson National Accelerator Facility (Jefferson Lab) has been funded by the US Navy to build an infra-red FEL driven by an energy-recovering compact SRF-based linear accelerator. The machine is to produce a 1 kW IR photon beam. The Jefferson Lab Accelerator Division is presently engaged in detailed design and beam dynamics studies for the driver accelerator. Principle beam dynamics and beam transport considerations include: (1) generation and transport of a high-quality, high-current, space-charge dominated beam; (2) the impact of coherent synchrotron radiation (CSR) during beam recirculation transport; (3) low-loss transport of a large momentum spread, high-current beam; (4) beam break up (BBU) instabilities in the recirculating accelerator; (5) impedance policing of transport system components; and (6) RF drive system control during energy recovery and FEL operation.

Douglas, D.R.

1997-12-01

218

Micromachined silicon slits for beam diagnostics in particle accelerators  

NASA Astrophysics Data System (ADS)

We report the fabrication process of a silicon target with a rectangular slit as an instrument for measuring the size and the angular divergence of high charge-density electron beams in particles accelerators. Bulk micromachining of silicon wafers by means of anisotropic etching allowed the definition of slits with parallel straight edges and low disuniformity. The disuniformities of the completed device evaluated by scanning electron microscopy were found to be tolerable with respect to the wavelength used in the experiments. Tests of the fabricated targets are in progress in the injector of ELETTRA, the synchrotron radiation facility in Trieste, Italy.

Cianci, Elena; Notargiacomo, Andrea; Cianchi, Alessandro; Foglietti, Vittorio

2001-09-01

219

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

SciTech Connect

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

Aachen DESY M.I.T. NIKHEF Peking Collaboration

1980-04-01

220

Longitudinal Coupling Impedance of a Hole In the Accelerator Beam Pipe  

E-print Network

Longitudinal Coupling Impedance of a Hole In the Accelerator Beam Pipe Yong-Chul Chae Advanced in the accelerator beam pipe. In various discontinuities such as RF cavities, bellows, and collimators, the coupling of a discontinuity in a typical beam pipe, often imposing a fundamental limitation of the numerical approach

Kemner, Ken

221

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

222

Reliability of Beam Loss Monitor Systems for the Large Hadron Collider  

SciTech Connect

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. [CERN, CH-1211 Geneva 23. Switzerland (Switzerland); Universite Blaise Pascal, 34 avenue Carnot, BP 185, F-63006 Clermont-Ferrand (France); Dehning, B. [CERN, CH-1211 Geneva 23. Switzerland (Switzerland); Santoni, C. [Universite Blaise Pascal, 34 avenue Carnot, BP 185, F-63006 Clermont-Ferrand (France)

2005-06-08

223

Progress on the relativistic klystron two-beam accelerator prototype  

SciTech Connect

The technical challenge for making two-beam accelerators into realizable power sources 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, l-MeV, electron induction prototype injector as a collaborative effort between LBL and LLNL. The electron source will be a 3.5"-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 120-ns flat top (1% energy variation), and a normalized edge emittance of less than 200 {pi}-mm-mr. Planned diagnostics include an isolated cathode with resistive divider for direct measurement of current emission, resistive-wall and magnetic probe current monitors for measuring beam current and centroid position, capacitive probes for measuring A-K gap voltage, an energy spectrometer, and a pepper-pot emittance diagnostic. Details of the injector, beam line, and diagnostics are presented.

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

1998-07-05

224

Progress on the relativistic klystron two-beam accelerator prototype  

NASA Astrophysics Data System (ADS)

The technical challenge for making two-beam accelerators into realizable power sources 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, electron induction prototype injector as a collaborative effort between LBL and LLNL. The electron source will be a 3.5?-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 120-ns flat top (1% energy variation), and a normalized edge emittance of less than 200 ?-mm-mr. Planned diagnostics include an isolated cathode with resistive divider for direct measurement of current emission, resistive-wall and magnetic probe current monitors for measuring beam current and centroid position, capacitive probes for measuring A-K gap voltage, an energy spectrometer, and a pepper-pot emittance diagnostic. Details of the injector, beam line, and diagnostics are presented.

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

1999-07-01

225

Progress on the relativistic klystron two-beam accelerator prototype  

SciTech Connect

The technical challenge for making two-beam accelerators into realizable power sources 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, electron induction prototype injector as a collaborative effort between LBL and LLNL. The electron source will be a 3.5''-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 120-ns flat top (1% energy variation), and a normalized edge emittance of less than 200 {pi}-mm-mr. Planned diagnostics include an isolated cathode with resistive divider for direct measurement of current emission, resistive-wall and magnetic probe current monitors for measuring beam current and centroid position, capacitive probes for measuring A-K gap voltage, an energy spectrometer, and a pepper-pot emittance diagnostic. Details of the injector, beam line, and diagnostics are presented.

Westenskow, G. A.; Houck, T. L. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Anderson, D. E.; Eylon, S.; Henestroza, E.; Lidia, S. M.; Vanecek, D. L.; Yu, S. S. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

1999-07-12

226

Electron Beam Transport in Advanced Plasma Wave Accelerators  

SciTech Connect

The primary goal of this grant was to develop a diagnostic for relativistic plasma wave accelerators based on injecting a low energy electron beam (5-50keV) perpendicular to the plasma wave and observing the distortion of the electron beam's cross section due to the plasma wave's electrostatic fields. The amount of distortion would be proportional to the plasma wave amplitude, and is the basis for the diagnostic. The beat-wave scheme for producing plasma waves, using two CO2 laser beam, was modeled using a leap-frog integration scheme to solve the equations of motion. Single electron trajectories and corresponding phase space diagrams were generated in order to study and understand the details of the interaction dynamics. The electron beam was simulated by combining thousands of single electrons, whose initial positions and momenta were selected by random number generators. The model was extended by including the interactions of the electrons with the CO2 laser fields of the beat wave, superimposed with the plasma wave fields. The results of the model were used to guide the design and construction of a small laboratory experiment that may be used to test the diagnostic idea.

Williams, Ronald L

2013-01-31

227

Levy-Student distributions for halos in accelerator beams  

SciTech Connect

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

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

2005-12-15

228

Lévy-Student distributions for halos in accelerator beams.  

PubMed

We describe the transverse beam distribution in particle accelerators within the controlled, stochastic dynamical scheme of stochastic mechanics (SM) which produces time reversal invariant diffusion processes. This leads to a linearized theory summarized in a Schrödinger-like (SL) equation. The space charge effects have been introduced in recent papers by coupling this S-L equation with the Maxwell equations. We analyze the space-charge effects to understand how the dynamics produces the actual beam distributions, and in particular we show how the stationary, self-consistent solutions are related to the (external and space-charge) potentials both when we suppose that the external field is harmonic (constant focusing), and when we a priori prescribe the shape of the stationary solution. We then proceed to discuss a few other ideas by introducing generalized Student distributions, namely, non-Gaussian, Lévy infinitely divisible (but not stable) distributions. We will discuss this idea from two different standpoints: (a) first by supposing that the stationary distribution of our (Wiener powered) SM model is a Student distribution; (b) by supposing that our model is based on a (non-Gaussian) Lévy process whose increments are Student distributed. We show that in the case (a) the longer tails of the power decay of the Student laws and in the case (b) the discontinuities of the Lévy-Student process can well account for the rare escape of particles from the beam core, and hence for the formation of a halo in intense beams. PMID:16486070

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

2005-12-01

229

Editorial: Focus on Laser- and Beam-Driven Plasma Accelerators  

NASA Astrophysics Data System (ADS)

The ability of short but intense laser pulses to generate high-energy electrons and ions from gaseous and solid targets has been well known since the early days of the laser fusion program. However, during the past decade there has been an explosion of experimental and theoretical activity in this area of laser-matter interaction, driven by the prospect of realizing table-top plasma accelerators for research, medical and industrial uses, and also relatively small and inexpensive plasma accelerators for high-energy physics at the frontier of particle physics. In this focus issue on laser- and beam-driven plasma accelerators, the latest advances in this field are described. Focus on Laser- and Beam-Driven Plasma Accelerators Contents Slow wave plasma structures for direct electron acceleration B D Layer, J P Palastro, A G York, T M Antonsen and H M Milchberg Cold injection for electron wakefield acceleration X Davoine, A Beck, A Lifschitz, V Malka and E Lefebvre Enhanced proton flux in the MeV range by defocused laser irradiation J S Green, D C Carroll, C Brenner, B Dromey, P S Foster, S Kar, Y T Li, K Markey, P McKenna, D Neely, A P L Robinson, M J V Streeter, M Tolley, C-G Wahlström, M H Xu and M Zepf Dose-dependent biological damage of tumour cells by laser-accelerated proton beams S D Kraft, C Richter, K Zeil, M Baumann, E Beyreuther, S Bock, M Bussmann, T E Cowan, Y Dammene, W Enghardt, U Helbig, L Karsch, T Kluge, L Laschinsky, E Lessmann, J Metzkes, D Naumburger, R Sauerbrey, M. Sc?rer, M Sobiella, J Woithe, U Schramm and J Pawelke The optimum plasma density for plasma wakefield excitation in the blowout regime W Lu, W An, M Zhou, C Joshi, C Huang and W B Mori Plasma wakefield acceleration experiments at FACET M J Hogan, T O Raubenheimer, A Seryi, P Muggli, T Katsouleas, C Huang, W Lu, W An, K A Marsh, W B Mori, C E Clayton and C Joshi Electron trapping and acceleration on a downward density ramp: a two-stage approach R M G M Trines, R Bingham, Z Najmudin, S Mangles, L O Silva, R Fonseca and P A Norreys Electro-optic shocks from blowout laser wakefields D F Gordon, A Ting, M H Helle, D Kaganovich and B Hafizi Onset of self-steepening of intense laser pulses in plasmas J Vieira, F Fiúza, L O Silva, M Tzoufras and W B Mori Analysis of laser wakefield dynamics in capillary tubes N E Andreev, K Cassou, F Wojda, G Genoud, M Burza, O Lundh, A Persson, B Cros, V E Fortov and C-G Wahlstrom Characterization of the beam loading effects in a laser plasma accelerator C Rechatin, J Faure, X Davoine, O Lundh, J Lim, A Ben-Ismaïl, F Burgy, A Tafzi, A Lifschitz, E Lefebvre and V Malka Energy gain scaling with plasma length and density in the plasma wakefield accelerator P Muggli, I Blumenfeld, C E Clayton, F J Decker, M J Hogan, C Huang, R Ischebeck, R H Iverson, C Joshi, T Katsouleas, N Kirby, W Lu, K A Marsh, W B Mori, E Oz, R H Siemann, D R Walz and M Zhou Generation of tens of GeV quasi-monoenergetic proton beams from a moving double layer formed by ultraintense lasers at intensity 1021-1023Wcm-2 Lu-Le Yu, Han Xu, Wei-Min Wang, Zheng-Ming Sheng, Bai-Fei Shen, Wei Yu and Jie Zhang Carbon ion acceleration from thin foil targets irradiated by ultrahigh-contrast, ultraintense laser pulses D C Carroll, O Tresca, R Prasad, L Romagnani, P S Foster, P Gallegos, S Ter-Avetisyan, J S Green, M J V Streeter, N Dover, C A J Palmer, C M Brenner, F H Cameron, K E Quinn, J Schreiber, A P L Robinson, T Baeva, M N Quinn, X H Yuan, Z Najmudin, M Zepf, D Neely, M Borghesi and P McKenna Numerical modelling of a 10-cm-long multi-GeV laser wakefield accelerator driven by a self-guided petawatt pulse S Y Kalmykov, S A Yi, A Beck, A F Lifschitz, X Davoine, E Lefebvre, A Pukhov, V Khudik, G Shvets, S A Reed, P Dong, X Wang, D Du, S Bedacht, R Zgadzaj, W Henderson, A Bernstein, G Dyer, M Martinez, E Gaul, T Ditmire and M C Downer Effects of laser prepulses on laser-induced proton generation D Batani, R Jafer, M Veltcheva, R Dezulian, O Lundh, F Lindau, A Persson, K Osvay, C-G Wahlström, D C Carroll, P McKenna, A Flacco and V Malka Proton accelerati

Joshi, Chan; Malka, Victor

2010-04-01

230

Vacuum electron acceleration and bunch compression by a flat-top laser beam  

SciTech Connect

The field intensity distribution and phase velocity characteristics of a flat-top laser beam are analyzed and discussed. The dynamics of electron acceleration in this kind of beam are investigated using three-dimensional test particle simulations. Compared with the standard (i.e., TEM{sub 00} mode) Gaussian beam, a flat-top laser beam has a stronger longitudinal electric field and a larger diffraction angle. These characteristics make it easier for electrons to be trapped and accelerated by the beam. With a flat-top shape, the laser beam is also applicable to the acceleration of low energy electron and bunch compression.

Wang, W.; Wang, P. X.; Ho, Y. K.; Kong, Q.; Gu, Y.; Wang, S. J. [Applied Ion Beam Physics Laboratory, Key Laboratory of the Ministry of Education, Institute of Modern Physics, Fudan University, Shanghai, 200433 (China) and Shanghai Institute of Laser Plasma, Shanghai, 201800 (China); Applied Ion Beam Physics Laboratory, Key Laboratory of the Ministry of Education, Institute of Modern Physics, Fudan University, Shanghai, 200433 (China); Shanghai Institute of Laser Plasma, Shanghai, 201800 (China)

2007-09-15

231

Beam Polarization at the ILC: the Physics Impact and the Accelerator Solutions  

SciTech Connect

In this contribution accelerator solutions for polarized beams and their impact on physics measurements are discussed. Focus are physics requirements for precision polarimetry near the interaction point and their realization with polarized sources. Based on the ILC baseline programme as described in the Reference Design Report (RDR), recent developments are discussed and evaluated taking into account physics runs at beam energies between 100 GeV and 250 GeV, as well as calibration runs on the Z-pole and options as the 1TeV upgrade and GigaZ. The studies, talks and discussions presented at this conference demonstrated that beam polarization and its measurement are crucial for the physics success of any future linear collider. To achieve the required precision it is absolutely decisive to employ multiple devices for testing and controlling the systematic uncertainties of each polarimeter. The polarimetry methods for the ILC are complementary: with the upstream polarimeter the measurements are performed in a clean environment, they are fast and allow to monitor time-dependent variations of polarization. The polarimeter downstream the IP will measure the disrupted beam resulting in high background and much lower statistics, but it allows access to the depolarization at the IP. Cross checks between the polarimeter results give redundancy and inter-calibration which is essential for high precision measurements. Current plans and issues for polarimeters and also energy spectrometers in the Beam Delivery System of the ILC are summarized in reference [28]. The ILC baseline design allows already from the beginning the operation with polarized electrons and polarized positrons provided the spin rotation and the fast helicity reversal for positrons will be implemented. A reversal of the positron helicity significantly slower than that of electrons is not recommended to not compromise the precision and hence the success of the ILC. Recently to use calibration data at the Z resonance for physics has been discussed. It looks promising but further studies are needed to evaluate and to optimize these measurements. Finally it should be remarked: many studies on different physics processes and scenarios at a future linear collider are done for high luminosities and high energy assuming small and well-known uncertainties. Polarization, especially positron polarization, is often considered as not that important. But in order to interpret data and to reduce ambiguities in the measurements, the polarization of electrons and positrons and their very precise knowledge are essential. The ILC design must offer this from the beginning to be prepared for the physics questions after years of LHC operation.

Aurand, B.; /Bonn U.; Bailey, I.; /Liverpool U.; Bartels, C.; /DESY /DESY, Zeuthen; Brachmann, A.; /SLAC; Clarke, J.; /Daresbury; Hartin, A.; /DESY /DESY, Zeuthen /Oxford U., JAI; Hauptman, J.; /Iowa State U.; Helebrant, C.; /DESY /DESY, Zeuthen; Hesselbach, S.; /Durham U., IPPP; Kafer, D.; List, J.; /DESY /DESY, Zeuthen; Lorenzon, W.; /Michigan U.; Marchesini, I.; Monig, Klaus; /DESY /DESY, Zeuthen; Moffeit, K.C.; /SLAC; Moortgat-Pick, G.; /Durham U., IPPP; Riemann, S.; Schalicke, A.; Schuler, P.; /DESY /DESY, Zeuthen; Starovoitov, P.; /Minsk, NCPHEP; Ushakov, A.; /DESY /DESY, Zeuthen /Bonn U. /SLAC

2011-11-23

232

Spin Transport and Polarimetry in the Beam Delivery System of the International Linear Collider  

E-print Network

Polarised electron and positron beams are key ingredients to the physics programme of future linear colliders. Due to the chiral nature of weak interactions in the Standard Model - and possibly beyond - the knowledge of the luminosity-weighted average beam polarisation at the $e^+e^-$ interaction point is of similar importance as the knowledge of the luminosity and has to be controlled to permille-level precision in order to fully exploit the physics potential. The current concept to reach this challenging goal combines measurements from Laser-Compton polarimeters before and after the interaction point with measurements at the interaction point. A key element for this enterprise is the understanding of spin-transport effects between the polarimeters and the interaction point as well as collision effects. We show that without collisions, the polarimeters can be cross-calibrated to 0.1 %, and we discuss in detail the impact of collision effects and beam parameters on the polarisation value relevant for the interpretation of the $e^+e^-$ collision data.

Moritz Beckmann; Jenny List; Annika Vauth; Benedikt Vormwald

2014-05-09

233

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

234

Reliability of Beam Loss Monitors System for the Large Hadron Collider  

SciTech Connect

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. [CERN, CH-1211 Geneva 23 (Switzerland); UNIVERSITE BLAISE PASCAL, 34 avenue Carnot BP 185, 63006 Clermont-Ferrand (France); Dehning, B. [CERN, CH-1211 Geneva 23 (Switzerland); Santoni, C. [UNIVERSITE BLAISE PASCAL, 34 avenue Carnot BP 185, 63006 Clermont-Ferrand (France)

2004-11-10

235

Luminometer for the future International Linear Collider -Simulation and Beam Test Results  

NASA Astrophysics Data System (ADS)

LumiCal will be the luminosity calorimeter for the proposed International Large Detector of the International Linear Collider (ILC). The ILC physics program requires the integrated luminosity to be measured with a relative precision on the order of 10e-3, or 10e-4 when running in GigaZ mode. Luminosity will be determined by counting Bhabha scattering events coincident in the two calorimeter modules placed symmetrically on opposite sides of the interaction point. To meet these goals, the energy resolution of the calorimeter must be better than 1.5% at high energies. LumiCal has been designed as a 30-layer sampling calorimeter with tungsten as the passive material and silicon as the active material. Monte Carlo simulation using the Geant4 software framework has been used to identify design elements which adversely impact energy resolution and correct for them without loss of statistics. BeamCal, covering polar angles smaller than LumiCal, will serve for beam tuning, luminosity optimisation and high energy electron detection. Secondly, prototypes of the sensors and electronics for both detectors have been evaluated during beam tests, the results of which are also presented here.

Aguilar, J. A.; Pawlik, B.; Kulis, S.; Idzik, M.; Chrzaszcz, M.; Daniluk, W.; Kielar, E.; Kotula, J.; Moszczynski, A.; Oliwa, K.; Wierba, W.; Zawiejski, L.; Afanaciev, K.; Henschel, H.; Ignatenko, A.; Kollowa, S.; Lohmann, W.; Novgorodova, O.; Schuwalow, S.; Levy, I.

236

Spin transport and polarimetry in the beam delivery system of the international linear collider  

NASA Astrophysics Data System (ADS)

Polarised electron and positron beams are key ingredients to the physics programme of future linear colliders. Due to the chiral nature of weak interactions in the Standard Model — and possibly beyond — the knowledge of the luminosity-weighted average beam polarisation at the e+e- interaction point is of similar importance as the knowledge of the luminosity and has to be controlled to permille-level precision in order to fully exploit the physics potential. The current concept to reach this challenging goal combines measurements from Laser-Compton polarimeters before and after the interaction point with measurements at the interaction point. A key element for this enterprise is the understanding of spin-transport effects between the polarimeters and the interaction point as well as collision effects. We show that without collisions, the polarimeters can be cross-calibrated to 0.1 %, and we discuss in detail the impact of collision effects and beam parameters on the polarisation value relevant for the interpretation of the e+e- collision data.

Beckmann, M.; List, J.; Vauth, A.; Vormwald, B.

2014-07-01

237

Effects of Ion Beam Waveform on Flyer Acceleration Produced by Pulsed Ion Beam Ablation Plasma  

NASA Astrophysics Data System (ADS)

The main objective of the current study is to clarify the influence of ion beam waveform and to investigate the momentum producing capability of flyer acceleration for propulsion applications, which is produced by irradiating target materials with pulsed ion beam. Al thin foil with a thickness of 50 ?m was used to form the high-pressure, high-temperature, and high-energy density ablation plasma when it interacts with pulsed ion beam. The analytical procedures are based on one-dimensional hydrodynamic equations together with a real gas equation of state. This paper presents not only the physical parameters of pulsed ion beam interaction with a target, but also shows the effects of ion beam waveform on momentum production. In addition, we describe the mechanism of ablation pressure formation and compare the results obtained for the rectangular and the parabolic waveform of ion beam irradiation. An ion beam with parabolic waveform produces ablation pressure more efficiently than a rectangular waveform. Propulsion performance is also estimated. An impulse bit of 50.7 mNs and a specific impulse of 5200 s are obtained at an electric power consumption of 1677 W.

Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro

238

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

239

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

240

Beam Position Monitoring using the HOM-Signals from a Damped and Detuned Accelerating Structure  

SciTech Connect

The Next and Global Linear Collider (NLC/GLC) designs require precision alignment of the beam in the accelerator structures to reduce short range wakefields. The moderately damped and detuned structures themselves provide suitable higher order mode (HOM) signals to measure this alignment. The modes in the lowest dipole band, whose frequencies range from 14-16 GHz, provide the strongest signals. To determine the position resolution they provide, an NLC/GLC prototype structure that was installed in the ASSET facility of the SLAC Linac was instrumented to downmix and digitize these signals. The beam position within the structure was determined by simultaneously measuring the signals at three frequencies (14.3, 15, 15.7 GHz) corresponding to modes localized at the beginning, the middle and the end of the 60 cm long structure. A resolution of 1 micron was achieved even with 28 dB signal attenuation, which is better than the 5 micron resolution required for the NLC/GLC.

Dobert, S; Adolphsen, C.; Jones, R.; Lewandowski, J.; Li, Z.; Pivi, M.; Wang, J.; /SLAC; Higo, T.; /KEK, Tsukuba

2005-05-17

241

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

SciTech Connect

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

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

2010-06-01

242

A review of high beam current RFQ accelerators and funnels  

SciTech Connect

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

Schneider, J.D.

1998-12-01

243

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

244

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

NASA Astrophysics Data System (ADS)

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; Miginsky, S.; Uk Jeong, Young

2012-07-01

245

Neutrino factory and beta beam: accelerator options for future neutrino experiments  

SciTech Connect

Two accelerator options for producing intense neutrino beams a Neutrino Factory based on stored muon beams and a Beta Beam facility based on stored beams of beta unstable ions are described. Technical challenges for each are described and current R&D efforts aimed at mitigating these challenges are indicated. Progress is being made in the design of both types of facility, each of which would extend the state-of-the-art in accelerator science.

Zisman, Michael S.

2012-06-03

246

A beam intensity monitor for the Loma Linda cancer therapy proton accelerator  

Microsoft Academic Search

A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and 250 MeV with an adjustable intensity between 10¹° and 10¹¹ protons

G. Coutrakon; Dan Miller; B. J. Kross; D. F. Anderson; P. Deluca Jr.; J. Siebers

1991-01-01

247

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

248

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

249

METHOD OF PRODUCING AND ACCELERATING AN ION BEAM  

NASA Technical Reports Server (NTRS)

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

Foster, John E. (Inventor)

2005-01-01

250

Vaccine Biotechnology by Accelerated Electron Beam and Microwave Irradiation  

NASA Astrophysics Data System (ADS)

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

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

2007-04-01

251

Education in a rapidly advancing technology: Accelerators and beams  

NASA Astrophysics Data System (ADS)

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

Month, Mel

2000-06-01

252

Radiobiological applications of ultrashort pulse laser-accelerated proton beams  

NASA Astrophysics Data System (ADS)

Ultrashort pulse laser proton acceleration is demonstrated to yield energies hitherto only accessible with high energy lasers. Up to 20 MeV protons are observed with the FZD Draco Ti:Sa laser with 30 fs pulses and only 2 J. This proton energy range allows for first well controlled applications. The radiation dose per shot observed for energies above 10 amounts to few Gy and thus provides excellent starting conditions for the irradiation of in vitro tumour cells with the aim of determining dose dependent biological damage. A first experiment demonstrates the availability of all components indispensable for systematic radiobiological studies: A laser-plasma accelerator providing stable proton spectra with maximum energy exceeding 15MeV over hundreds of pulses and applicable doses of a few Gy within few minutes, a beam transport and filtering system, an in-air irradiation site, a dedicated dosimetry system providing both online dose monitoring and a precise absolute dose information applied to the cell sample, and the full infrastructure for analysing radiation induced damage in cells.[4pt] [1] S.D. Kraft, K. Zeil, et al., New J. Phys. 12, 085003 (2010).

Zeil, Karl; Kraft, S.; Bussmann, M.; Cowan, T. E.; Kluge, T.; Metzkes, J.; Richter, T.; Sauerbrey, R.; Schramm, U.; Richter, C.; Beyreuther, E.; Enghardt, W.; Karsch, L.; Laschinsky, L.; Naumburger, D.; Pawelke, J.

2010-11-01

253

Education in a rapidly advancing technology: Accelerators and beams  

SciTech Connect

The field of accelerators and beams (A and B) is one of today's fast changing technologies. Because university faculties have not been able to keep pace with the associated advancing knowledge, universities have not been able to play their traditional role of educating the scientists and engineers needed to sustain this technology for use in science, industry, commerce, and defense. This problem for A and B is described and addressed. The solution proposed, a type of ''distance'' education, is the U.S. Particle Accelerator School (USPAS) created in the early 1980s. USPAS provides the universities with a means of serving the education needs of the institutions using A and B, primarily but not exclusively the national laboratories. The field of A and B is briefly summarized. The need for education outside the university framework, the raison d'etre for USPAS, the USPAS method, program structure, and curriculum, and particular USPAS-university connections are explained. The management of USPAS is analyzed, including its unique administrative structure, its institutional ties, and its operations, finance, marketing, and governmental relations. USPAS performance over the years is documented and a business assessment is made. Finally, there is a brief discussion of the future potential for this type of educational program, including possible extrapolation to new areas and/or different environments, in particular, its extra-government potential and its international possibilities. (c) 2000 American Association of Physics Teachers.

Month, Mel [Brookhaven National Laboratory/US Particle Accelerator School, Building 902A, Upton, New York 11973-5000 (United States)] [Brookhaven National Laboratory/US Particle Accelerator School, Building 902A, Upton, New York 11973-5000 (United States)

2000-06-01

254

Scintillator diagnostics for the detection of laser accelerated ion beams  

NASA Astrophysics Data System (ADS)

Laser plasma interaction with ultraintense pulses present exciting schemes for accelerating ions. One of the advantages conferred by using a gaseous laser and target is the potential for a fast (several Hz) repetition rate. This requires diagnostics which are not only suited for a single shot configuration, but also for repeated use. We consider several scintillators as candidates for an imaging diagnostic for protons accelerated to MeV energies by a CO2 laser focused on a gas jet target. We have measured the response of chromium-doped alumina (chromox) and polyvinyl toluene (PVT) screens to protons in the 2-8 MeV range. We have calibrated the luminescent yield in terms of photons emitted per incident proton for each scintillator. We also discuss how light scattering and material properties affect detector resolution. Furthermore, we consider material damage and the presence of an afterglow under intense exposures. Our analysis reveals a near order of magnitude greater yield from chromox in response to proton beams at > 8 MeV energies, while scattering effects favor PVT-based scintillators at lower energies.

Cook, N.; Tresca, O.; Lefferts, R.

2014-09-01

255

Particle selection and beam collimation system for laser-accelerated proton beam therapy.  

PubMed

In a laser-accelerated proton therapy system, the initial protons have broad energy and angular distributions, which are not suitable for direct therapeutic applications. A compact particle selection and collimation device is needed to deliver small pencil beams of protons with desired energy spectra. In this work, we characterize a superconducting magnet system that produces a desired magnetic field configuration to spread the protons with different energies and emitting angles for particle selection. Four magnets are set side by side along the beam axis; each is made of NbTi wires which carry a current density of approximately 10(5) A/cm2 at 4.2 K, and produces a magnetic field of approximately 4.4 T in the corresponding region. Collimation is applied to both the entrance and the exit of the particle selection system to generate a desired proton pencil beam. In the middle of the magnet system, where the magnetic field is close to zero, a particle selection collimator allows only the protons with desired energies to pass through for therapy. Simulations of proton transport in the presence of the magnetic field show that the selected protons have successfully refocused on the beam axis after passing through the magnetic field with the optimal magnet system. The energy spread for any given characteristic proton energy has been obtained. It is shown that the energy spread is a function of the magnetic field strength and collimator size and reaches the full width at half maximum of 25 MeV for 230 MeV protons. Dose distributions have also been calculated with the GEANT3 Monte Carlo code to study the dosimetric properties of the laser-accelerated proton beams for radiation therapy applications. PMID:15839352

Luo, Wei; Fourkal, Eugene; Li, Jinsheng; Ma, Chang-Ming

2005-03-01

256

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

257

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

258

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

259

Reconstruction of Initial Beam Conditions at the Exit of the DARHT II Accelerator  

Microsoft Academic Search

We consider a technique to determine the initial beam conditions of the DARHT II Accelerator by measuring the beam size under three different magnetic transport settings. This may be time gated to resolve the parameters as a function of time within the 2000 nsec pulse. This technique leads to three equations in three unknowns with solution giving the accelerator exit

Arthur C. Paul

2000-01-01

260

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

261

Energy amplification and beam bunching in a pulse line ion accelerator  

NASA Astrophysics Data System (ADS)

In a first beam dynamics validation experiment for a new Pulse Line Ion Acceleration (PLIA) concept, the predicted energy amplification and beam bunching were experimentally observed. Beam energy modulation of -80 to +150keV was measured using a PLIA input voltage waveform of -21 to +12kV. Ion pulses accelerated by 150 keV, and bunching by a factor of 4 were simultaneously achieved. The measured longitudinal phase space and current waveform of the accelerated beam are in good agreement with 3D particle-in-cell simulations.

Roy, Prabir K.; Waldron, William L.; Yu, Simon S.; Coleman, Joshua E.; Henestroza, Enrique; Grote, David P.; Baca, David; Bieniosek, Frank M.; Briggs, Richard J.; Davidson, Ronald C.; Eylon, Shmuel; Friedman, Alex; Greenway, Wayne G.; Leitner, Matthaeus; Logan, Grant B.; Reginato, Louis L.; Seidl, Peter A.

2006-07-01

262

Energy Amplification and Beam Bunching in a Pulse Line Ion Accelerator  

SciTech Connect

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

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

2006-06-08

263

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

NASA Astrophysics Data System (ADS)

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

Chikvashvili, Ioseb

2011-11-01

264

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

265

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

SciTech Connect

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

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

2013-09-15

266

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

267

Energy amplification and beam bunching in a pulse line ion accelerator  

Microsoft Academic Search

In a first beam dynamics validation experiment for a new Pulse Line Ion Acceleration (PLIA) concept, the predicted energy amplification and beam bunching were experimentally observed. Beam energy modulation of -80 to +150keV was measured using a PLIA input voltage waveform of -21 to +12kV. Ion pulses accelerated by 150 keV, and bunching by a factor of 4 were simultaneously

Prabir K. Roy; William L. Waldron; Simon S. Yu; Joshua E. Coleman; Enrique Henestroza; David P. Grote; David Baca; Frank M. Bieniosek; Richard J. Briggs; Ronald C. Davidson; Shmuel Eylon; Alex Friedman; Wayne G. Greenway; Matthaeus Leitner; Grant B. Logan; Louis L. Reginato; Peter A. Seidl

2006-01-01

268

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

269

Suppressing Electron Cloud in Future Linear Colliders  

SciTech Connect

Any accelerator circulating positively charged beams can suffer from a build-up of an electron cloud (EC) in the beam pipe. The cloud develops through ionization of residual gases, synchrotron radiation and secondary electron emission and, when severe, can cause instability, emittance blow-up or loss of the circulating beam. The electron cloud is potentially a luminosity limiting effect for both the Large Hadron Collider (LHC) and the International Linear Collider (ILC). For the ILC positron damping ring, the development of the electron cloud must be suppressed. This paper discusses the state-of-the-art of the ongoing SLAC and international R&D program to study potential remedies.

Pivi, M; Kirby, R.E.; Raubenheimer, T.O.; /SLAC; Le Pimpec, F.; /PSI, Villigen

2005-05-27

270

Physics and Application of Intense Charged Particle Beams4. Collective Particle Accelerator and Intense Charged Particle Beams  

Microsoft Academic Search

The concept and technology of collective accelerators using an intense electron beam which were studied extensively in the '70s to '80s, are reviewed briefly. The two most prominent kinds of acceleration schemes during this period were the type of linear arrangement of the system and that using an Electron Ring as a vehicle. Although only very small activity of experimental

Sunao Kawasaki

1999-01-01

271

A new beam loss detector for low-energy proton and heavy-ion accelerators  

NASA Astrophysics Data System (ADS)

The Facility for Rare Isotope Beams (FRIB) to be constructed at Michigan State University shall deliver a continuous, 400 kW heavy ion beam to the isotope production target. This beam is capable of inflicting serious damage on accelerator components, e.g. superconducting RF accelerating cavities. A Beam Loss Monitoring (BLM) System is essential for detecting beam loss with sufficient sensitivity and promptness to inform the machine protection system (MPS) and operations personnel of impending dangerous losses. Radiation transport simulations reveal shortcomings in the use of ionization chambers for the detection of beam losses in low-energy, heavy-ion accelerators. Radiation cross-talk effects due to the folded geometry of the FRIB LINAC pose further complications to locating specific points of beam loss. We propose a newly developed device, named the Loss Monitor Ring (LMR1

Liu, Zhengzheng; Crisp, Jenna; Russo, Tom; Webber, Robert; Zhang, Yan

2014-12-01

272

Seismic studies for Fermilab future collider projects  

SciTech Connect

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

Lauh, J.; Shiltsev, V.

1997-11-01

273

Feasibility study of aluminum beam tube for the collider: An option for no-coating and no-liner  

SciTech Connect

This report proposes to use a single-layer beam tube made of high strength, high resistivity aluminum alloy (such as 7039-T61 or A7N01) to replace the double-layer copper coated stainless steel tube in the SSC Collider. The main reasons are: (1) a potential saving of about $23 million which is basically the baseline cost of the copper coating and (2) the use of an extruded aluminum tube consisting of a beam chamber and a pumping chamber may solve the vacuum problem without any liner.

Chou, W.

1994-07-01

274

The project of laser polarimeter for beam energy measurement of VEPP-4M collider by resonance depolarization method  

NASA Astrophysics Data System (ADS)

To high precision measurement of Upsilon-meson masses with KEDR detector on VEPP-4M collider the beam energy calibration is needed. The project of laser polarimeter for beam energy measurement by resonance depolarization method is discussed. The polarization measurement is based on up-down asymmetry of Compton backscatterring of circular polarized photons on vertical polarized electrons. Scattered photons are registered by two-coordinate detector based on Gas Electron Multiplier. Expected effect is about 1.6 % with 10 ? confidence level.

Blinov, V. E.; Kaminsky, V. V.; Kudryavtsev, V. N.; Muchnoi, N. Yu; Nikitin, S. A.; Nikolaev, I. B.; Shekhtman, L. I.

2014-09-01

275

Performance of MBE-4: An experimental multiple beam induction linear accelerator for heavy ions  

SciTech Connect

An experimental induction linac, called MBE-4, has been constructed to demonstrate acceleration and current amplification of multiple heavy ion beams. This work is part of a program to study the use of such an accelerator as a driver for heavy ion inertial fusion. MBE-4 is 16m long and accelerates four space-charge-dominated beams of singly-charged cesium ions, in this case from 200 keV to 700 keV, amplifying the current in each beam from 10mA by a factor of nine. Construction of the experiment was completed late in 1987 and we present the results of detailed measurements of the longitudinal beam dynamics. Of particular interest is the contribution of acceleration errors to the growth of current fluctuations and to the longitudinal emittance. The effectiveness of the longitudinal focusing, accomplished by means of the controlled time dependence of the accelerating fields, is also discussed. 4 refs., 5 figs., 1 tab.

Warwick, A.I.; Fessenden, T.J.; Keefe, D.; Kim, C.H.; Meuth, H.

1988-06-01

276

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

277

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

278

Beam shaping assembly optimization for (7)Li(p,n)(7)Be accelerator based BNCT.  

PubMed

Within the framework of accelerator-based BNCT, a project to develop a folded Tandem-ElectroStatic-Quadrupole accelerator is under way at the Atomic Energy Commission of Argentina. The proposed accelerator is conceived to deliver a proton beam of 30mA at about 2.5MeV. In this work we explore a Beam Shaping Assembly (BSA) design based on the (7)Li(p,n)(7)Be neutron production reaction to obtain neutron beams to treat deep seated tumors. PMID:24345525

Minsky, D M; Kreiner, A J

2014-06-01

279

Beam loading in a laser-plasma accelerator using a near-hollow plasma channel  

SciTech Connect

Beam loading in laser-plasma accelerators using a near-hollow plasma channel is examined in the linear wake regime. It is shown that, by properly shaping and phasing the witness particle beam, high-gradient acceleration can be achieved with high-efficiency, and without induced energy spread or emittance growth. Both electron and positron beams can be accelerated in this plasma channel geometry. Matched propagation of electron beams can be achieved by the focusing force provided by the channel density. For positron beams, matched propagation can be achieved in a hollow plasma channel with external focusing. The efficiency of energy transfer from the wake to a witness beam is calculated for single ultra-short bunches and bunch trains.

Schroeder, C. B.; Benedetti, C.; Esarey, E.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2013-12-15

280

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

281

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

282

Acceleration, current amplification and emittance in MBE-4, an experimental beam induction linear accelerator for heavy ions  

SciTech Connect

We report on the implementation of a second schedule of acceleration and current amplification in MBE-4. Control of the beam current within the bunch is improved over that in the first schedule by the addition of several small amplitude induction pulsers to compensate for acceleration errors and to control the ends of the bunch. Measurements of the longitudinal and transverse emittance are presented. 5 refs., 3 figs., 1 tab.

Warwick, A.I.; Gough, D.E.; Keefe, D.; Meuth, H.

1988-10-01

283

Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC  

ScienceCinema

Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

Andrei Seryi

2010-01-08

284

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

285

A new possibility of low-Z gas stripper for high power uranium beam acceleration alternative to C-foil  

Microsoft Academic Search

The RIKEN accelerator complex started feeding the next-generation exotic beam facility RIBF (RadioIsotope Beam Factory) with heavy ion beams from 2007 after the successful commissioning at the end of 2006. Many elaborating improvements increased the intensity of the various heavy ion beams from 2007 to 2010. However, the available beam intensity especially of uranium beam is far below our goal

H. Okuno; A. Hershcovitch; N. Fukunishi; A. Goto; H. Hasebe; H. Imao; O. Kamigaito; M. Kase; H. Kuboki; Y. Yano

2010-01-01

286

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

287

DEVELOPMENT OF ACCELERATOR DATA REPORTING SYSTEM AND ITS APPLICATION TO TREND ANALYSIS OF BEAM CURRENT DATA  

SciTech Connect

Detailed ongoing information about the ion beam quality is crucial to the successful operation of the Spallation Neutron Source at Oak Ridge National Laboratory. In order to provide the highest possible neutron production time, ion beam quality is monitored to isolate possible problems or performance-related issues throughout the accelerator and accumulator ring. For example, beam current monitor (BCM) data is used to determine the quality of the beam transport through the accelerator. In this study, a reporting system infrastructure was implemented and used to generate a trend analysis report of the BCM data. The BCM data was analyzed to facilitate the identifi cation of monitor calibration issues, beam trends, beam abnormalities, beam deviations and overall beam quality. A comparison between transformed BCM report data and accelerator log entries shows promising results which represent correlations between the data and changes made within the accelerator. The BCM analysis report is one of many reports within a system that assist in providing overall beam quality information to facilitate successful beam operation. In future reports, additional data manipulation functions and analysis can be implemented and applied. Built-in and user-defi ned analytic functions are available throughout the reporting system and can be reused with new data.

Padilla, M.J.; Blokland, W.

2009-01-01

288

Transverse wake field effects on intense bunches with application to the SLAC linear collider  

SciTech Connect

The theory of transverse beam break-up is summarized and briefly discussed in this paper. It is then applied to the SLAC linear accelerator to give the various design tolerances for beam injection and alignment of accelerator components for the linear collider operation.

Chao, A.W.; Richter, B.; Yao, C.Y.

1980-07-01

289

Beam acceleration test in negative-ion based NBI system for JT-60U  

NASA Astrophysics Data System (ADS)

Beam extraction and acceleration test in the Negative Ion Based Neutral Beam Injector for JT-60U has been started using one ion source that is designed to produce a 500 keV, 22 A D- ion beam. Deuterium negative ions are produced in a cesium-seeded semi-cylindrical plasma generator and accelerated by a multi-aperture three-stage electrostatic accelerator. In the preliminary experiment of beam acceleration, the D- ion beam of 13.5 A was successfully accelerated to 400 keV for a pulse duration of 0.12 s. The negative ion beam power was 5.4 MW. The operating gas pressure in the plasma generator was as low as 0.22 Pa. The highest energy beam of 460 keV, 2.4 A, 0.44 s was also obtained. The ratio of extracted electron current to extracted negative ion current is estimated Ie/ID-<1. It was confirmed that the electron leak from the extractor to the accelerator is suppressed efficiently by the effects of biassing, electron trapping gap and magnetic field.

Watanabe, K.; Akino, N.; Araki, M.; Ebisawa, N.; Fujiwara, Y.; Hanada, M.; Honda, A.; Inoue, T.; Itoh, T.; Kawai, M.; Kazawa, M.; Koizumi, J.; Kuriyama, M.; Miyamoto, K.; Miyamoto, N.; Mogaki, K.; Nagase, A.; Ohara, Y.; Ohga, T.; Okumura, Y.; Oohara, H.; Ohshima, K.; Satoh, F.; Takahashi, S.; Takenouchi, T.; Usami, H.; Usui, K.; Yamamoto, M.; Yamazaki, T.

1996-07-01

290

Acceleration of the polarized proton beam at the KEK 12 GeV ps  

NASA Astrophysics Data System (ADS)

Acceleration of the polarized proton beam at the KEK PS up to 3.5 GeV is described. In the booster synchrotron, 75% of the linac beam polarization was preserved without any correction for the depolarizing resonances. In the main ring, almost 100% of the booster beam polarization was preserved at 3.5 GeV by the fast passage method for the intrinsic resonances and by the closed orbit correction for the imperfection resonances. The KEK PS is the first cascaded synchrotron which has demonstrated acceleration of a polarized beam.

Sato, H.; Arakawa, D.; Hiramatsu, S.; Mori, Y.; Ikegami, K.; Takagi, A.; Toyama, T.; Ueno, A.; Imai, K.

1988-11-01

291

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

292

Supra-bubble regime for laser acceleration of cold electron beams in tenuous plasma  

E-print Network

Supra-bubble regime for laser acceleration of cold electron beams in tenuous plasma V. I. Geyko,1 I the most common scalings from the original Ref. 1 for this comparison; for more accurate models, see Refs

293

Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic  

SciTech Connect

The design and current status of experiments to couple the Tapered Hybrid Undulator (THUNDER) to the Lawrence Berkeley National Laboratory (LBNL) laser plasma accelerator (LPA) to measure electron beam energy spread and emittance are presented.

Bakeman, M.S.; Van Tilborg, J.; Nakamura, K.; Gonsalves, A.; Osterhoff, J.; Sokollik, T.; Lin, C.; Robinson, K.E.; Schroeder, C.B.; Toth, Cs.; Weingartner, R.; Gruner, F.; Esarey, E.; Leemans, W.P.

2010-06-01

294

Unveiling the Orbital Angular Momentum and Acceleration of Electron Beams  

NASA Astrophysics Data System (ADS)

New forms of electron beams have been intensively investigated recently, including vortex beams carrying orbital angular momentum, as well as Airy beams propagating along a parabolic trajectory. Their traits may be harnessed for applications in materials science, electron microscopy, and interferometry, and so it is important to measure their properties with ease. Here, we show how one may immediately quantify these beams' parameters without need for additional fabrication or nonstandard microscopic tools. Our experimental results are backed by numerical simulations and analytic derivation.

Shiloh, Roy; Tsur, Yuval; Remez, Roei; Lereah, Yossi; Malomed, Boris A.; Shvedov, Vladlen; Hnatovsky, Cyril; Krolikowski, Wieslaw; Arie, Ady

2015-03-01

295

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

SciTech Connect

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

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

2004-07-08

296

Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators  

Microsoft Academic Search

Self Magnetically Insulated Transmission Lines (MITL) adders were used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC\\/SMILE electron beam accelerator to produce high quality, small radius (r(sub rho) less than 2 cm), 11 - 15 MeV, 50 - 100-kA beams with a small transverse

S. L. Shope; M. G. Mazarakis; C. A. Frost; J. W. Poukey; B. N. Turman

1991-01-01

297

A facility upgrade at Texas A&M University for accelerated radioactive beams  

Microsoft Academic Search

.  The Cyclotron Institute at Texas A&M University is carrying out an upgrade project\\u000a which will lead to accelerated radioactive ion beams at intermediate energies. The project\\u000a involves recommissioning a K150 cyclotron for acceleration of stable beams which will be used\\u000a to produce radioactive ions. Both light-ion and heavy-ion guides will be used\\u000a to stop and transport the radioactive ions to

R. E. Tribble; F. Abegglen; G. Chubarian; H. L. Clark; G. Derrig; G. Kim; D. May; G. A. Souliotis; G. Tabacaru

2007-01-01

298

Review of Polarized Proton Beam Acceleration at KEK-PS in the 1980's  

NASA Astrophysics Data System (ADS)

A polarized proton beam was accelerated at the KEK-PS in the late 1980's. This report will review the activities for the polarized beam acceleration in both the 500 MeV booster and the 12 GeV Main Ring. Some depolarization resonances were passed using the spin-flip techniques. The effects on the polarization caused by a synchrotron side-band at a strong intrinsic resonance were observed.

Ohmori, C.; Hiramatsu, S.; Sato, H.; Toyama, T.

2003-05-01

299

Limiting electron beam current for cyclic induction acceleration in a constant guide field  

SciTech Connect

Theoretical relations are derived for the limiting beam current in a cyclic induction accelerator (CIA) with a constant guide field. The calculations are in agreement with the available experimental data. It is shown that the limiting average beam current in a CIA is of the order of 100 microamperes, i.e., the level attained in microtrons and linear accelerators. The CIA may find industrial applications.

Kanunnikov, V.N.

1982-09-01

300

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

PubMed Central

Background: Ion beam has been used in cancer treatment, and has a unique preferable feature to deposit its main energy inside a human body so that cancer cell could be killed by the ion beam. However, conventional ion accelerator tends to be huge in its size and its cost. In this paper a future intense-laser ion accelerator is proposed to make the ion accelerator compact. Subjects and methods: An intense femtosecond pulsed laser was employed to accelerate ions. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching and the ion particle energy control. In the study particle computer simulations were performed to solve the issues, and each component was designed to control the ion beam quality. Results: When an intense laser illuminates a target, electrons in the target are accelerated and leave from the target; temporarily a strong electric field is formed between the high-energy electrons and the target ions, and the target ions are accelerated. The energy efficiency from the laser to ions was improved by using a solid target with a fine sub-wavelength structure or by a near-critical density gas plasma. The ion beam collimation was realized by holes behind the solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching were successfully realized by a multi-stage laser-target interaction. Conclusions: The present study proposed a novel concept for a future compact laser ion accelerator, based on each component study required to control the ion beam quality and parameters. PMID:24155555

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

2013-01-01

301

Confined flow multiple beam shaping at the powerful klystron for the superconducting linear electron-positron colliders  

NASA Astrophysics Data System (ADS)

The results of modeling of the electro-optic system proposed and designed for the powerful multiple beam klystron Toshiba E3736 have been represented. Toshiba E3736 is the 10MW L-band six-beam klystron being developed for the superconductive accelerator projects TESLA (XFEL), ILC. The key features of device are the new compact scheme of the confined flow multiple beam shaping, the most low cathode loading (<2.1 A/cm2) in comparison with analogues, a controlled beamlet size (diameter) in the drift tubes of klystron.

Larionov, A. V.

2006-05-01

302

The muon collider (Sandro's snake)  

SciTech Connect

This paper describes a feasibility study for the design of a muon collider. Recognized the fact that the particle lifetime increases linearly with the energy, 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 and affordable. All acceleration and cooling steps are executed in a single pass essentially along a curvilinear and open path. We do not believe it is possible to handle the beam otherwise in circular and closed rings, as it has been proposed in the past. The example shown in this paper describes a muon collider at the energy of 250 GeV per beam and a luminosity of 4 [times] 10[sup 28] cm[sup [minus]2]s[sup [minus]1]. We have adopted an extrapolation of the stochastic cooling method for the reduction of the beam emittance.

Ruggiero, A.G.

1992-01-01

303

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

DOE PAGESBeta

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

Shishlo, A.; Aleksandrov, A.

2013-06-01

304

Luminosity Potentials in Colliders with Electron Cooling  

SciTech Connect

Luminosity upgrades of colliders with hadron beams, existing or designed, tend to require decreasing of beam emittances and maintaining them using a suitable cooling technique. The breakthroughs of recent years: realization of beam energy recovery in superconducting linear accelerators, flat to round beam transformations, new beam transport concepts (discontinuous solenoid, circulator rings, hollow beams, dispersive cooling) ? have promoted the feasibility of efficient electron cooling of intense high energy hadron beams. Electron cooling, in cooperation with strong SRF field in storage rings, will allow one to obtain very short hadron bunches, as result of which the luminosity can be raised by making a low beta-star. Short bunches also would makecrab crossing feasible, that allows one to remove the parasitic beam-beam interactions and maximize the collision rate. Cooling also results in flatness of uncoupled beam equilibrium; this can be used to diminish the IBS impact on luminosity

Derbenev, Yaroslav

2003-05-01

305

On the polarized beam acceleration in medium energy synchrotrons  

SciTech Connect

This lecture note reviews physics of spin motion in a synchrotron, spin depolarization mechanisms of spin resonances, and methods of overcoming the spin resonances during acceleration. Techniques used in accelerating polarized ions in the low/medium energy synchrotrons, such as the ZGS, the AGS, SATURNE, and the KEK PS and PS Booster are discussed. Problems related to polarized proton acceleration with snakes or partial snake are also examined.

Lee, S.Y.

1992-12-31

306

Photoelectron linear accelerator for producing a low emittance polarized electron beam  

DOEpatents

A photoelectron linear accelerator for producing a low emittance polarized electric beam. The accelerator includes a tube having an inner wall, the inner tube wall being coated by a getter material. A portable, or demountable, cathode plug is mounted within said tube, the surface of said cathode having a semiconductor material formed thereon.

Yu, David U.; Clendenin, James E.; Kirby, Robert E.

2004-06-01

307

Status of LBL/LLNL FEL (free electron laser) research for two beam accelerator applications  

SciTech Connect

We review the status of free electron laser (FEL) research being conducted at LBL and LLNL as part of a broader program of research on two beam accelerators (TBAs). Induction accelerator-driven FELs for use as power sources for high-gradient accelerators are discussed, along with preliminary cost estimates for this type of power source. Finally, a promising new version of an FEL/TBA is described. 25 refs., 1 fig., 3 tabs.

Hopkins, D.B.; Sessler, A.M.

1989-03-01

308

Narrow spread electron beams from a laser-plasma wakefield accelerator  

Microsoft Academic Search

The Advanced Laser-Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme is developing laserplasma accelerators for the production of ultra-short electron bunches with subsequent generation of incoherent radiation pulses from plasma and coherent short-wavelength radiation pulses from a free-electron laser (FEL). The first quantitative measurements of the electron energy spectra have been made on the University of Strathclyde ALPHA-X wakefield acceleration beam

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

2009-01-01

309

Center for Beam Physics papers  

SciTech Connect

Six papers are included in this collection. They cover: a second interaction region for gamma-gamma, gamma-electron and electron- electron collisions; constraints on laser-driven accelerators for a high-energy linear collider; progress on the design of a high luminosity muon-muon collider; RF power source development at the RTA test facility; sensitivity studies of crystalline beams; and single bunch collective effects in muon colliders.

Sessler, A.M. [ed.

1996-06-01

310

A prototype of a beam steering assistant tool for accelerator operations  

SciTech Connect

The CEBAF accelerator provides nuclear physics experiments at Jefferson Lab with high quality electron beams. Three experimental end stations can simultaneously receive the beams with different energies and intensities. For each operational mode, the accelerator setup procedures are complicated and require very careful checking of beam spot sizes and positions on multiple beam viewers. To simplify these procedures and make them reproducible, a beam steering assistant GUI tool has been created. The tool is implemented as a multi-window control screen. The screen has an interactive graphical object window, which is an overlay on top of a digitized live video image from a beam viewer. It allows a user to easily create and edit any graphical objects consisting of text, ellipses, and lines, right above the live beam viewer image and then save them in a file that is called a beam steering template. The template can show, for example, the area within which the beam must always be on the viewer. Later, this template can be loaded in the interactive graphical object window to help accelerator operators steer the beam to the specified area on the viewer.

M. Bickley; P. Chevtsov

2006-10-24

311

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

E-print Network

Particle-in-cell (PIC) simulation results of sustained acceleration of electron-positron (e+e-) plasmas by comoving electromagnetic (EM) pulses are presented. When a thin slab of overdense e+e- plasma is irradiated with linear-polarized ultra-intense short laser pulses from both sides, the pulses are transmitted when the plasma is compressed to thinner than ~ 2 relativistic skin depths. A fraction of the plasma is then captured and efficiently accelerated by self-induced JxB forces. For 1 micron laser and 1021Wcm-2 intensity, the maximum energy exceeds GeV in a picosecond.

Liang, E

2006-01-01

312

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

SciTech Connect

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

Hutton, R.D.

1994-01-01

313

Analytical solutions for transient and steady state beam loading in arbitrary traveling wave accelerating structures  

Microsoft Academic Search

Analytical solutions are derived for both transient and steady state gradient distributions in the traveling wave (TW) accelerating structures with arbitrary variation of parameters over the structure length. The results of the unloaded and beam loaded cases are presented. Finally, the exact analytical shape of the rf pulse waveform was found in order to apply the transient beam loading compensation

A. Lunin; V. Yakovlev; A. Grudiev

2011-01-01

314

A stochastic model for the semiclassical collective dynamics of charged beams in particle accelerators  

Microsoft Academic Search

A recent proposal (see quant-ph\\/9803068) to simulate semiclassical corrections to classical dynamics by suitable classical stochastic fluctuations is applied to the specific instance of charged beam dynamics in particle accelerators. The resulting picture is that the collective beam dynamics, at the leading semiclassical order in Planck constant can be described by a particular diffusion process, the Nelson process, which is

Salvatore De Martino; Silvio De Siena; Fabrizio Illuminati

1998-01-01

315

Laser-driven generation of high-current ion beams using skin-layer ponderomotive acceleration  

NASA Astrophysics Data System (ADS)

Basic properties of generation of high-current ion beams using the skin-layer ponderomotive acceleration (S-LPA) mechanism, induced by a short laser pulse interacting with a solid target are studied. Simplified scaling laws for the ion energies, the ion current densities, the ion beam intensities, and the efficiency of ions' production are derived for the cases of subrelativistic and relativistic laser-plasma interactions. The results of the time-of-flight measurements performed for both backward-accelerated ion beams from a massive target and forward-accelerated beams from a thin foil target irradiated by 1-ps laser pulse of intensity up to [similar] 1017 W/cm2 are presented. The ion current densities and the ion beam intensities at the source obtained from these measurements are compared to the ones achieved in recent short-pulse experiments using the target normal sheath acceleration (TNSA) mechanism at relativistic (>1019 W/cm2) laser intensities. The possibility of application of high-current ion beams produced by S-LPA at relativistic intensities for fast ignition of fusion target is considered. Using the derived scaling laws for the ion beam parameters, the achievement conditions for ignition of compressed DT fuel with ion beams driven by ps laser pulses of total energy [less-than-or-equal] 100 kJ is shown.

Badziak, J.; Glowacz, S.; Jablonski, S.; Parys, P.; Wolowski, J.; Hora, H.

2005-10-01

316

Accelerator and Ion Beam Tradeoffs for Studies of Warm DenseMatter  

Microsoft Academic Search

One approach for heating a target to ''Warm Dense Matter'' conditions (similar, for example, to the interiors of giant planets or certain stages in inertial confinement fusion targets), is to use intense ion beams as the heating source (see refs.[6] and [7] and references therein for motivation and accelerator concepts). By consideration of ion beam phase-space constraints, both at the

J. J. Barnard; R. J. Briggs; D. A. Callahan; R. C. Davidson; A. Friedman; L. Grisham; E. P. Lee; R. W. Lee; B. G. Logan; C. L. Olson; D. V. Rose; P. Santhanam; A. M. Sessler; J. W. Staples; M. Tabak; D. R. Welch; J. S. Wurtele; S. S. Yu

2006-01-01

317

Heavy ion inertial fusion: interface between target gain, accelerator phase space and reactor beam transport revisited  

SciTech Connect

Recently revised estimates of target gain have added additional optimistic inputs to the interface between targets, accelerators and fusion chamber beam transport. But it remains valid that neutralization of the beams in the fusion chamber is useful if ion charge state Z > 1 or if > 1 kA per beamlet is to be propagated. Some engineering and economic considerations favor higher currents.

Barletta, W.A.; Fawley, W.M.; Judd, D.L.; Mark, J.W.K.; Yu, S.S.

1984-02-22

318

Switching the acceleration direction of Airy beams by a nonlinear optical process  

E-print Network

beams generated by nonlinear three- wave mixing processes in an asymmetrically poled nonlinear photonic3 x,y exp ik3x , the 2D nonlinear wave equation takes the form A2 x,y + k2 2 A2 x,y = - A3A1 *Switching the acceleration direction of Airy beams by a nonlinear optical process Ido Dolev,1

Arie, Ady

319

High-energy Laser-accelerated Electron Beams for Long-range Interrogation  

SciTech Connect

We are studying the use of 0.1-1.0 GeV laser-accelerated electron beams as active interrogation probes for long-standoff radiography or nuclear activation of concealed special nuclear material. Use of beams in this energy range is largely unexplored, but such beams could provide notable advantages over lower-energy beams and x-rays. High-energy laser-accelerated electrons exhibit large penetration range through air and solids, and low beam divergence for both direct beams and secondary Bremsstrahlung x-rays. We present laboratory measurements of radiography and activation, using the high-power Diodes laser system at the University of Nebraska, as well as MCNP and GEANT Monte Carlo simulation results used to aid experiment design and interpretation.

Cunningham, Nathaniel J.; Banerjee, Sudeep; Ramanathan, Vidya; Powers, Nathan; Chandler-Smith, Nate; Umstadter, Donald [Department of Physics and Astronomy, University of Nebraska, Lincoln, NE 68588-0111 (United States); Vane, Randy; Schultz, David; Beene, James [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States); Pozzi, Sara; Clarke, Shaun [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109-2104 (United States)

2009-03-10

320

High-Energy Laser-Accelerated Electron Beams for Long-Range Interrogation  

SciTech Connect

We are studying the use of 0.1 1.0 GeV laser-accelerated electron beams as active interrogation probes for long-standoff radiography or nuclear activation of concealed special nuclear material. Use of beams in this energy range is largely unexplored, but such beams could provide notable advantages over lower-energy beams and x-rays. High-energy laser-accelerated electrons exhibit large penetration range through air and solids, and low beam divergence for both direct beams and secondary Bremsstrahlung x-rays. We present laboratory measurements of radiography and activation, using the high-power Diodes laser system at the University of Nebraska, as well as MCNP and GEANT Monte Carlo simulation results used to aid experiment design and interpretation.

Cummingham, N. J. [University of Nebraska, Lincoln; Banerjee, Sudeep [University of Nebraska, Lincoln; Ramanathan, Vidya [University of Nebraska, Lincoln; Powell, Nathan [University of Nebraska, Lincoln; Chandler-Smith, Nate [University of Nebraska, Lincoln; Vane, C Randy [ORNL; Schultz, David Robert [ORNL; Pozzi, Sara [University of Michigan; Clarke, Shaun [University of Michigan; Beene, James R [ORNL; Umstadter, Donald [University of Nebraska, Lincoln

2009-01-01

321

Alignment tolerance of accelerating structures and corrections for future linear colliders  

SciTech Connect

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

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

1995-06-01

322

Electron beam dynamics and self-cooling up to PeV level due to betatron radiation in plasma-based accelerators  

NASA Astrophysics Data System (ADS)

In plasma-based accelerators, electrons are accelerated by ultrahigh gradient of 1-100GV/m and undergo the focusing force with the same order as the accelerating force. Heated electrons are injected in a plasma wake and exhibit the betatron oscillation that generates synchrotron radiation. Intense betatron radiation from laser-plasma accelerators is attractive x-ray/gamma-ray sources, while it produces radiation loss and significant effects on energy spread and transverse emittance via the radiation reaction force. In this article, electron beam dynamics on transverse emittance and energy spread with considering radiation reaction effects are studied numerically. It is found that the emittance growth and the energy spread damping initially dominate and balance with radiative damping due to the betatron radiation. Afterward the emittance turns to decrease at a constant rate and leads to the equilibrium at a nanometer radian level with growth due to Coulomb scattering at PeV-level energies. A constant radiation loss rate RT=2/3 is found without regard to the electron beam and plasma conditions. Self-cooling of electron beams due to betatron radiation may guarantee TeV-range linear colliders and give hints on astrophysical ultrahigh-energy phenomena.

Deng, Aihua; Nakajima, Kazuhisa; Liu, Jiansheng; Shen, Baifei; Zhang, Xiaomei; Yu, Yahong; Li, Wentao; Li, Ruxin; Xu, Zhizhan

2012-08-01

323

Development of a low-energy beam transport system at KBSI heavy-ion accelerator  

NASA Astrophysics Data System (ADS)

The Korea Basic Science Institute has developed a heavy ion accelerator for fast neutron radiography [1]. To meet the requirements for fast neutron generation, we have developed an accelerator system that consists of an electron cyclotron resonance ion source (ECR-IS), low-energy beam transport (LEBT) system, radio-frequency quadrupole (RFQ), medium-energy beam transport system, and drift tube linac. In this paper, we present the development of the LEBT system as a part of the heavy ion accelerator system, which operates from the ECR-IS to the RFQ entrance.

Bahng, Jungbae; Lee, Byoung-Seob; Sato, Yoichi; Ok, Jung-Woo; Park, Jin Yong; Yoon, Jang-Hee; Choi, Seyong; Won, Mi-Sook; Kim, Eun-San

2015-01-01

324

Beam instrumentation for future high intense hadron accelerators at Fermilab  

SciTech Connect

High intensity hadron beams of up to 2 MW beam power are a key element of new proposed experimental facilities at Fermilab. Project X, which includes a SCRF 8 GeV H{sup -} linac, will be the centerpiece of future HEP activities in the neutrino sector. After a short overview of this, and other proposed projects, we present the current status of the beam instrumentation activities at Fermilab with a few examples. With upgrades and improvements they can meet the requirements of the new beam facilities, however design and development of new instruments is needed, as shown by the prototype and conceptual examples in the last section.

Wendt, M.; Hu, M.; Tassotto, G.; Thurman-Keup, R.; Scarpine, V.; Shin, S.; Zagel, J.; /Fermilab

2008-08-01

325

Acceleration of electrons by a tightly focused intense laser beam.  

PubMed

The recent proposal to use Weinger transformation field (WTF) [Opt. Express 17, 4959-4969 (2009)] for describing tightly focused laser beams is investigated here in detail. In order to validate the accuracy of WTF, we derive the numerical field (NF) from the plane wave spectrum method. WTF is compared with NF and Lax series field (LSF). Results show that LSF is accurate close to the beam axis and divergent far from the beam axis, and WTF is always accurate. Moreover, electron dynamics in a tightly focused intense laser beam are simulated by LSF, WTF and NF, respectively. The results obtained by WTF are shown to be accurate. PMID:19582099

Li, Jian-Xing; Zang, Wei-Ping; Li, Ya-Dong; Tian, Jian-Guo

2009-07-01

326

Unveiling the orbital angular momentum and acceleration of electron beams.  

PubMed

New forms of electron beams have been intensively investigated recently, including vortex beams carrying orbital angular momentum, as well as Airy beams propagating along a parabolic trajectory. Their traits may be harnessed for applications in materials science, electron microscopy, and interferometry, and so it is important to measure their properties with ease. Here, we show how one may immediately quantify these beams' parameters without need for additional fabrication or nonstandard microscopic tools. Our experimental results are backed by numerical simulations and analytic derivation. PMID:25793830

Shiloh, Roy; Tsur, Yuval; Remez, Roei; Lereah, Yossi; Malomed, Boris A; Shvedov, Vladlen; Hnatovsky, Cyril; Krolikowski, Wieslaw; Arie, Ady

2015-03-01

327

Proceedings of the international workshop on next-generation linear colliders  

SciTech Connect

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

Riordan, M. (ed.)

1988-12-01

328

System modeling for the longitudinal beam dynamics control problem in heavy ion induction accelerators  

SciTech Connect

We address the problem of developing system models that are suitable for studying the control of the longitudinal beam dynamics in induction accelerators for heavy ions. In particular, we present the preliminary results of our efforts to devise a general framework for building detailed, integrated models of accelerator systems consisting of pulsed power modular circuits, induction cells, beam dynamics, and control system elements. Such a framework will permit us to analyze and design the pulsed power modulators and the control systems required to effect precise control over the longitudinal beam dynamics.

Payne, A.N.

1993-05-17

329

Initial electron-beam results from the DARHT-II linear induction accelerator  

Microsoft Academic Search

The DARHT-II linear-induction accelerator has been successfully operated at 1.2-1.3 kA and 12.5-12.7 MeV to demonstrate the production and acceleration of an electron beam. Beam pulse lengths for these experiments were varied from 0.5 ?s to 1.2 ?s full-width half-maximum. A low-frequency inductance-capacitance (LC) oscillation of diode voltage and current resulted in an oscillation of the beam position through interaction

Carl Ekdahl; E. O. Abeyta; H. Bender; W. Broste; C. Carlson; L. Caudill; K. C. D. Chan; Y. J. Chen; D. Dalmas; G. Durtschi; S. Eversole; S. Eylon; W. Fawley; D. Frayer; R. Gallegos; J. Harrison; E. Henestroza; M. Holzscheiter; T. Houck; T. Hughes; S. Humphries; D. Johnson; J. Johnson; K. Jones; E. Jacquez; B. Trent McCuistian; A. Meidinger; N. Montoya; C. Mostrom; K. Moy; K. Nielsen; D. Oro; L. Rodriguez; P. Rodriguez; M. Sanchez; M. Schauer; D. Simmons; H. V. Smith; J. Studebaker; R. Sturgess; G. Sullivan; C. Swinney; R. Temple; C. Y. Tom; S. S. Yu

2005-01-01

330

H-mode accelerating structures with permanent-magnet quadrupole beam focusing  

NASA Astrophysics Data System (ADS)

We have developed high-efficiency normal-conducting rf accelerating structures by combining H-mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of interdigital H-mode (IH-PMQ) structures is 10-20 times higher than that of a conventional drift-tube linac, while the transverse size is 4-5 times smaller. Results of the combined 3D modeling—electromagnetic computations, multiparticle beam-dynamics simulations with high currents, and thermal-stress analysis—for an IH-PMQ accelerator tank are presented. The accelerating-field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. Examples of cross-bar H-mode structures with PMQ focusing for higher beam velocities are also presented. H-PMQ accelerating structures following a short radio-frequency quadrupole accelerator can be used both in the front end of ion linacs or in stand-alone applications.

Kurennoy, S. S.; Rybarcyk, L. J.; O'Hara, J. F.; Olivas, E. R.; Wangler, T. P.

2012-09-01

331

Study of the transverse beam motion in the DARHT Phase II accelerator  

SciTech Connect

The accelerator for the second-axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility will accelerate a 4-kA, 3-MeV, 2--µs long electron current pulse to 20 MeV. The energy variation of the beam within the flat-top portion of the current pulse is (plus or equal to) 0.5%. The performance of the DARHT Phase II radiographic machine requires the transverse beam motion to be much less than the beam spot size which is about 1.5 mm diameter on the x-ray converter. In general, the leading causes of the transverse beam motion in an accelerator are the beam breakup instability (BBU) and the corkscrew motion. We have modeled the transverse beam motion in the DARHT Phase II accelerator with various magnetic tunes and accelerator cell configurations by using the BREAKUP code. The predicted sensitivity of corkscrew motion and BBU growth to different tuning algorithms will be presented.

Chen, Yu-Jiuan; Fawley, W M; Houck, T L

1998-08-20

332

H-mode accelerating structures with permanent-magnet quadrupole beam focusing  

DOE PAGESBeta

We have developed high-efficiency normal-conducting rf accelerating structures by combining H -mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of interdigital H -mode (IH-PMQ) structures is 10–20 times higher than that of a conventional drift-tube linac, while the transverse size is 4–5 times smaller. Results of the combined 3D modeling—electromagnetic computations, multiparticle beam-dynamics simulations with high currents, and thermal-stress analysis—for an IH-PMQ accelerator tank are presented. The accelerating-field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. Examples of cross-bar H -mode structures with PMQ focusing for higher beam velocities are also presented. H -PMQ accelerating structures following a short radio-frequency quadrupole accelerator can be used both in the front end of ion linacs or in stand-alone applications.

Kurennoy, S. S.; Rybarcyk, L. J.; O’Hara, J. F.; Olivas, E. R.; Wangler, T. P.

2012-09-01

333

Reconstruction of Initial Beam Conditions at the Exit of the DARHT II Accelerator  

SciTech Connect

We consider a technique of determining the initial beam conditions of the DARHT II accelerator by measuring the beam size under three different magnetic transport settings. This may be time gated to resolve the parameters as a function of time within the 2000 nsec pulse. This technique leads to three equations in three unknowns with solution giving the accelerator exit beam radius, tilt, and emittance. We find that systematic errors cancel and so are not a problem in the initial beam condition unfolding. Random uncorrelated shot to shot errors can be managed by one of three strategies: (1) make the transport system optically de-magnifying; (2) average over many individual shots; or (3) make the random uncorrelated shot to shot errors sufficiently small. The high power of the DARHT II beam requires that the beam transport system leading to a radius measuring apparatus be optically magnifying. This means that the shot to shot random errors must either be made small (less than about 1%) or that we average each of the three beam radius determinations over many individual shots. We find that for the anticipated DARHT II beam parameters that 60 to 120 shots should be sufficient to determine the accelerator beam parameters.

Paul, A.C.

2000-02-18

334

Pulsed power for particle beam accelerators in military applications  

SciTech Connect

Techniques useful for generating and conditioning power for high energy pulsed accelerators with potential weapon applications are described. Pulsed electron accelerators are exemplified by ETA and ATA at Lawrence Livermore Laboratories and RADLAC at Sandia Laboratories Albuquerque. Pulse-power techniques used in other applications are briefly mentioned, including some that may be useful for collective ion accelerators. The limitations of pulse-power and the general directions of desirable development are illustrated. The main needs are to increase repetition rate and to decrease size.

Smith, I.D.

1980-06-20

335

Beam dynamics studies on the ISAC-II post-accelerator at TRIUMF.  

SciTech Connect

The TRIUMF/ISAC facility, now a world leader in rare isotope production and acceleration, is constructing ISAC-II [1, 2], that will allow the acceleration of ion beams with 3 {le} A/q {le} 7 to an energy of at least 6.5 MeV/u for masses up to 150. The upgrade will include the addition of a superconducting heavy-ion linac delivering an effective voltage of 43 MV. The first order design of the new transfer lines and post-accelerator have been optimized to provide simultaneous acceleration of several charge states (multicharge). The quarter wave resonators providing the acceleration have inherent rf electric and magnetic asymmetric components that complicate multi-charge acceleration and can lead to transverse emittance growth. In particular we report the realistic field simulations of the medium beta section of the SC-DTL for multi-charge acceleration.

Pasini, M.; Laxdal, R. E.; Ostroumov, P. N.

2002-06-26

336

CHARACTERIZATION OF A HIGH CURRENT INDUCTION ACCELERATOR ELECTRON BEAM VIA OPTICAL TRANSITION RADIATION FROM DIELECTRIC FOILS  

SciTech Connect

Traditionally, thin metal foils are employed for optical transition radiation (OTR) beam diagnostics but the possibility of shorting accelerator insulating surfaces and modifying accelerating fields are concerns. The successful utilization of dielectric foils in place of metal ones could alleviate these issues but necessitates more understanding of the OTR data for inferring desired beam parameters because of the dielectric's finite permittivity. Additionally, the temperature dependence of the relevant foil parameters due to beam heating should be accounted for. Here, we present and discuss sample synthetic diagnostic results of Kapton OTR spot-size measurements from the Flash X-Ray (FXR) accelerator which studies these and sightline effects. These simulations show that in some cases, the observed spot-sizes and radii are noticeably larger than the beam radii.

Tang, V; Brown, C; Houck, T

2007-06-13

337

Beam manipulation for compact laser wakefield accelerator based free-electron lasers  

NASA Astrophysics Data System (ADS)

Free-electron lasers (FELs) are a unique source of light, particularly in the x-ray domain. After the success of FELs based on conventional acceleration using radio-frequency cavities, an important challenge is the development of FELs based on electron bunching accelerated by a laser wakefield accelerator (LWFA). However, the present LWFA electron bunch properties do not permit use directly for a significant FEL amplification. It is known that longitudinal decompression of electron beams delivered by state-of-the-art LWFA eases the FEL process. We propose here a second order transverse beam manipulation turning the large inherent transverse chromatic emittances of LWFA beams into direct FEL gain advantage. Numerical simulations are presented showing that this beam manipulation can further enhance by orders of magnitude the peak power of the radiation.

Loulergue, A.; Labat, M.; Evain, C.; Benabderrahmane, C.; Malka, V.; Couprie, M. E.

2015-02-01

338

A high average power beam dump for an electron accelerator  

NASA Astrophysics Data System (ADS)

The electron beam dump for Cornell University's Energy Recovery Linac (ERL) prototype injector was designed and manufactured to absorb 600 kW of electron beam power at beam energies between 5 and 15 MeV. It is constructed from an aluminum alloy using a cylindrical/conical geometry, with water cooling channels between an inner vacuum chamber and an outer jacket. The electron beam is defocused and its centroid is rastered around the axis of the dump to dilute the power density. A flexible joint connects the inner body and the outer jacket to minimize thermal stress. A quadrant detector at the entrance to the dump monitors the electron beam position and rastering. Electron scattering calculations, thermal and thermomechanical stress analysis, and radiation calculations are presented.

Liu, Xianghong; Bazarov, Ivan; Dunham, Bruce M.; Kostroun, Vaclav O.; Li, Yulin; Smolenski, Karl W.

2013-05-01

339

Tevatron End-of-Run Beam Physics Experiments  

SciTech Connect

Before the Tevatron Collider Run II ended in September of 2011, a number of specialized beam study periods were dedicated to the experiments on various accelerator physics concepts and effects during the last year of the machine operation. The study topics included collimation with bent crystals and hollow electron beams, diffusion measurements and various aspects of beam-beam interactions. In this report we concentrate on the subject of beam-beam interactions, summarizing the results of beam experiments. The covered topics include offset collisions, coherent beam stability, effect of the bunch-length-to-beta-function ratio, and operation of AC dipole with colliding beams.

Valishev, A.; /Fermilab; Gu, X.; Miyamoto, R.; White, S.; /BNL; Schmidt, F.; /CERN; Qiang, J.; /LBNL

2012-05-01

340

Suppressing beam-centroid motion in a long-pulse linear induction accelerator  

NASA Astrophysics Data System (ADS)

The second axis of the dual-axis radiography of hydrodynamic testing (DARHT) facility produces up to four radiographs within an interval of 1.6?s. It does this by slicing four micropulses out of a 2-?s long electron beam pulse and focusing them onto a bremsstrahlung converter target. The 1.8-kA beam pulse is created by a dispenser cathode diode and accelerated to more than 16 MeV by the unique DARHT Axis-II linear induction accelerator (LIA). Beam motion in the accelerator would be a problem for multipulse flash radiography. High-frequency motion, such as from beam-breakup (BBU) 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. Using the methods discussed, we have reduced beam motion at the accelerator exit to less than 2% of the beam envelope radius for the high-frequency BBU, and less than 1/3 of the envelope radius for the low-frequency sweep.

Ekdahl, Carl; Abeyta, E. O.; Archuleta, R.; Bender, H.; Broste, W.; Carlson, C.; Cook, G.; Frayer, D.; Harrison, J.; Hughes, T.; Johnson, J.; Jacquez, E.; McCuistian, B. Trent; Montoya, N.; Nath, S.; Nielsen, K.; Rose, C.; Schulze, M.; Smith, H. V.; Thoma, C.; Tom, C. Y.

2011-12-01

341

Calculation of abort thresholds for the Beam Loss Monitoring System of the Large Hadron Collider at CERN  

E-print Network

The Beam Loss Monitoring (BLM) System is one of the most critical machine protection systems for the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), Switzerland. Its main purpose is to protect the superconducting magnets from quenches and other equipment from damage by requesting a beam abort when the measured losses exceed any of the predefined threshold levels. The system consist of circa 4000 ionization chambers which are installed around the 27 kilometres ring (LHC). This study aims to choose a technical platform and produce a system that addresses all of the limitations with the current system that is used for the calculation of the LHC BLM abort threshold values. To achieve this, a comparison and benchmarking of the Java and .NET technical platforms is performed in order to establish the most suitable solution. To establish which technical platform is a successful replacement of the current abort threshold calculator, comparable prototype systems in Java and .NET we...

Nemcic, Martin; Dehning, Bernd

342

Status of LBL/LLNL FEL (Free Electron Laser) research for two beam accelerator applications  

NASA Astrophysics Data System (ADS)

For this workshop, we review the status of free electron laser (FEL) research being conducted at LBL and LLNL as part of a broader program of research on two beam accelerators (TBAs). We discuss measurements made on high power 35 and 138 GHz FELs and their problem areas. Experience with 35 GHz accelerator section fabrication is summarized. Induction accelerator-driven FELs for use as power sources for high-gradient accelerators are discussed, along with preliminary cost estimates for this type of power source. Finally, a promising new version of an FEL/TBA is discussed.

Hopkins, D. B.; Sessler, A. M.

1988-11-01

343

Status of LBL/LLNL FEL (free electron laser) research for two beam accelerator applications  

SciTech Connect

For this workshop, we review the status of free electron laser (FEL) research being conducted at LBL and LLNL as part of a broader program of research on two beam accelerators (TBAs). We discuss measurements made on high power 35 and 138 GHz FELs and their problem areas. Experience with 35 GHz accelerator section fabrication is summarized. Induction accelerator-driven FELs for use as power sources for high-gradient accelerators are discussed, along with preliminary cost estimates for this type of power source. Finally, a promising new version of an FEL/TBA is discussed. 22 refs., 7 figs., 5 tabs.

Hopkins, D.B.; Sessler, A.M.

1988-11-01

344

Muon Collider Task Force Report  

SciTech Connect

Muon Colliders offer a possible long term path to lepton-lepton collisions at center-of-mass energies {radical}s {ge} 1 TeV. In October 2006 the Muon Collider Task Force (MCTF) proposed a program of advanced accelerator R&D aimed at developing the Muon Collider concept. The proposed R&D program was motivated by progress on Muon Collider design in general, and in particular, by new ideas that have emerged on muon cooling channel design. The scope of the proposed MCTF R&D program includes muon collider design studies, helical cooling channel design and simulation, high temperature superconducting solenoid studies, an experimental program using beams to test cooling channel RF cavities and a 6D cooling demonstration channel. The first year of MCTF activities are summarized in this report together with a brief description of the anticipated FY08 R&D activities. In its first year the MCTF has made progress on (1) Muon Collider ring studies, (2) 6D cooling channel design and simulation studies with an emphasis on the HCC scheme, (3) beam preparations for the first HPRF cavity beam test, (4) preparations for an HCC four-coil test, (5) further development of the MANX experiment ideas and studies of the muon beam possibilities at Fermilab, (6) studies of how to integrate RF into an HCC in preparation for a component development program, and (7) HTS conductor and magnet studies to prepare for an evaluation of the prospects for of an HTS high-field solenoid build for a muon cooling channel.

Ankenbrandt, C.; Alexahin, Y.; Balbekov, V.; Barzi, E.; Bhat, C.; Broemmelsiek, D.; Bross, A.; Burov, A.; Drozhdin, A.; Finley, D.; Geer, S.; /Fermilab /Argonne /Brookhaven /Jefferson Lab /LBL, Berkeley /MUONS Inc., Batavia /UCLA /UC, Riverside /Mississippi U.

2007-12-01

345

Beam loading by distributed injection of electrons in a plasma wakefield accelerator.  

PubMed

We show through experiments and supporting simulations that propagation of a highly relativistic and dense electron bunch through a plasma can lead to distributed injection of electrons, which depletes the accelerating field, i.e., beam loads the wake. The source of the injected electrons is ionization of the second electron of rubidium (Rb II) within the wake. This injection of excess charge is large enough to severely beam load the wake, and thereby reduce the transformer ratio T. The reduction of the average T with increasing beam loading is quantified for the first time by measuring the ratio of peak energy gain and loss of electrons while changing the beam emittance. Simulations show that beam loading by Rb II electrons contributes to the reduction of the peak accelerating field from its weakly loaded value of 43??GV/m to a strongly loaded value of 26??GV/m. PMID:24484020

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

2014-01-17

346

Beam Loading by Distributed Injection of Electrons in a Plasma Wakefield Accelerator  

NASA Astrophysics Data System (ADS)

We show through experiments and supporting simulations that propagation of a highly relativistic and dense electron bunch through a plasma can lead to distributed injection of electrons, which depletes the accelerating field, i.e., beam loads the wake. The source of the injected electrons is ionization of the second electron of rubidium (Rb II) within the wake. This injection of excess charge is large enough to severely beam load the wake, and thereby reduce the transformer ratio T. The reduction of the average T with increasing beam loading is quantified for the first time by measuring the ratio of peak energy gain and loss of electrons while changing the beam emittance. Simulations show that beam loading by Rb II electrons contributes to the reduction of the peak accelerating field from its weakly loaded value of 43 GV/m to a strongly loaded value of 26 GV/m.

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

2014-01-01

347

Preliminary Results of RMS Emittance Measurements Performed on the Subpicosecond Accelerator Using Beam Position Monitors  

NASA Astrophysics Data System (ADS)

The Subpicosecond Accelerator (SPA) at Los Alamos National Laboratory is a 1300MHz, 8MeV photoinjector. Concerned mainly with the exploration of bunched electron beams, the SPA facility is also used for a variety of other research. One ongoing task is the exploitation of the second moment properties of beam position monitor (BPM) signals to measure the rms emittance.(R.H. Miller, et al., ``Nonintercepting Emittance Monitor,'' Proc. 12th Int. Conf. on High Energy Accelerators, (Fermilab, 1983), p. 602 (1983).) The unique properties of photoinjector beams make Gaussian assumptions about their distribution inaccurate and traditional methods of measuring the rms emittance fail.(Bruce E. Carlsten, et. al., ``Measuring Emittance of Non-thermalized Electron Beams from Photoinjectors,'' 14th International Free Electron Conference, Kobe, Japan, August 23-28, 1992, Los Alamos National Laboratory document LAUR 92 2561.) Utilizing BPMs, however, requires no beam distribution assumptions. Presented here are our first emittance measurements with this method on SPA.

Russell, Steven J.

1997-05-01

348

Conceptual design of the Relativistic Heavy Ion Collider: RHIC  

SciTech Connect

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

Samios, Nicholas P.

1986-05-01

349

Beam-induced Electron Loading Effects in High Pressure Cavities for a Muon Collider  

Microsoft Academic Search

Ionization cooling is a critical building block for the realization of a muon collider. To suppress breakdown in the presence of the external magnetic field, an idea of using an RF cavity filled with high pressure hydrogen gas is being considered for the cooling channel design. One possible problem expected in the high pressure RF cavity is, however, the dissipation

M. Chung; A. Tollestrup; A. Jansson; K. Yonehara; Z. Insepov

2010-01-01

350

3-D model of beam kicker in DARHT-2 accelerator  

NASA Astrophysics Data System (ADS)

The DARHT-2 beamline uses a fast stripline kicker developed at LLNL [1] to create a series of short pulses out of a 2 microsecond pulse for use in high resolution x-ray radiography. Normally, a static bias dipole bends the 2 kA, 18 MeV electron beam off axis into a dump. When the fast stripline kicker is activated, the static dipole kick is cancelled by the dynamic dipole field of the kicker, and the beam travels to the x-ray converter. 3-D PIC simulations are performed to compute the effect of the kicker on the beam. The calculations incorporate the kicker biplate conductor geometry, allowing for accurate modeling of the effects of higher multipole fields as well as beam wakefield effects. Beam emittance growth through the kicker is investigated for various beam loads. [1] B.R. Poole and Y.-J. Chen, "Particle Simulations of DARHT-2 Transport System", Proc. PAC 2001 Conference (http://accelconf.web.cern.ch/AccelConf/p01/PAPERS/RPPH034.PDF).

Thoma, Carsten; Genoni, Thomas; Hughes, Thomas

2003-10-01

351

Transport and Non-Invasive Position Detection of Electron Beams from Laser-Plasma Accelerators  

SciTech Connect

The controlled imaging and transport of ultra-relativistic electrons from laser-plasma accelerators is of crucial importance to further use of these beams, e.g. in high peak-brightness light sources. We present our plans to realize beam transport with miniature permanent quadrupole magnets from the electron source through our THUNDER undulator. Simulation results demonstrate the importance of beam imaging by investigating the generated XUV-photon flux. In addition, first experimental findings of utilizing cavity-based monitors for non-invasive beam-position measurements in a noisy electromagnetic laser-plasma environment are discussed.

Osterhoff, Jens; Sokollik, Thomas; Nakamura, Kei; Bakeman, Michael; Weingartner, R; Gonsalves, Anthony; Shiraishi, Satomi; Lin, Chen; vanTilborg, Jeroen; Geddes, Cameron; Schroeder, Carl; Esarey, Eric; Toth, Csaba; DeSantis, Stefano; Byrd, John; Gruner, F; Leemans, Wim

2011-07-20

352

Fast beam chopper at SARAF accelerator via RF deflector before RFQ  

NASA Astrophysics Data System (ADS)

We describe design and simulations of a fast beam chopper for the SARAF accelerator based on an RF deflector preceding the RFQ. The SARAF 176 MHz RFQ, takes a DC proton or deuteron beam and accelerates and bunches the beam to 1.5 MeV/u and bunches of 0.3 ns width (FWHM) every 5.5 ns respectively. The deflector acts on the DC beam and sweeps away all but one of the pre-accelerated (pre)-bunches prior to the actual bunching and acceleration in the RFQ. Simulations were performed for a fast beam chopper, where several deflection voltage pulsing schemes have been investigated. The simulations show effective chopping with alternating positive and negative HV applied to the deflector with a fast HV switch, where the beam is transmitted to the RFQ during the cross-over of the rise(fall) of the HV switching. The simulations show that we can obtain efficient deflection of unwanted bunches, with 60% transmission efficiency for the desired bunch. The present design is for a chopper that will provide 0.3 ns bunches with a repetition rate of ~ 105bunches/sec. Plans for a fast chopper with higher repetition rates of ~ 106 Hz are discussed.

Shor, A.; Vartsky, D.; Dangendorf, V.; Bar, D.; Ben Aliz, Y.; Berkovits, D.; Brandis, M.; Goldberg, M. B.; Grin, A.; Mardor, I.; Mor, I.; Weissman, L.

2012-06-01

353

Muon muon collider: Feasibility study  

SciTech Connect

A feasibility study is presented of a 2 + 2 TeV muon collider with a luminosity of L = 10{sup 35} cm{sup {minus}2} s{sup {minus}1}. The resulting design is not optimized for performance, and certainly not for cost; however, it does suffice--the authors believe--to allow them to make a credible case, that a muon collider is a serious possibility for particle physics and, therefore, worthy of R and D support so that the reality of, and interest in, a muon collider can be better assayed. The goal of this support would be to completely assess the physics potential and to evaluate the cost and development of the necessary technology. The muon collider complex consists of components which first produce copious pions, then capture the pions and the resulting muons from their decay; this is followed by an ionization cooling channel to reduce the longitudinal and transverse emittance of the muon beam. The next stage is to accelerate the muons and, finally, inject them into a collider ring which has a small beta function at the colliding point. This is the first attempt at a point design and it will require further study and optimization. Experimental work will be needed to verify the validity of diverse crucial elements in the design.

NONE

1996-06-18

354

Initial operation of the Tevatron collider  

SciTech Connect

The Tevatron is now the highest energy proton synchrotron and the only accelerator made with superconducting magnets. Operating since 1983 as a fixed-target machine at energies up to 800 GeV, it has now been modified to operate as a 900 GeV antiproton-proton collider. This paper describes the initial operation of the machine in this mode. The new features of the Fermilab complex, including the antiproton source and the Main Ring injector with its two overpasses and new rf requirements, are discussed. Beam characteristics in the Tevatron (including lifetimes, emittances, luminosity, beam-beam tune shifts, backgrounds, and low beta complications), the coordination of the steps in the accelerator chain, and the commissioning history are also discussed. Finally, some plans for the improvement of the collider are presented.

Johnson, R.

1987-03-01

355

Optimization of Drive-Bunch Current Profile for Enhanced Transformer Ratio in Beam-Driven Acceleration Techniques  

SciTech Connect

In recent years, wakefield acceleration has gained attention due to its high acceleration gradients and cost effectiveness. In beam-driven wakefield acceleration, a critical parameter to optimize is the transformer ratio. It has been shown that current shaping of electron beams allows for enhanced (> 2) transformer ratios. In this paper we present the optimization of the pulse shape of the drive bunch for dielectric-wakefield acceleration.

Lemery, F.; Mihalcea, D.; Prokop, C.R.; /Northern Illinois U.; Piot, P.; /Northern Illinois U. /Fermilab

2012-07-08

356

Use of Oriented Crystals at High-Energy Accelerators  

SciTech Connect

The application of bent crystals for extracting accelerated beams from high-energy accelerators is reviewed. The results of realizing highly efficient extraction of protons from the IHEP accelerator are presented. Proposals on using oriented crystals for designing efficient positron sources at linear colliders and on developing new undulators are discussed.

Kotov, V.I.; Afonin, A.G.; Baranov, V.T.; Biryukov, V.M.; Ivanov, Yu.M.; Kardash, A.A.; Maisheev, V.A.; Terekhov, V.I.; Troyanov, E.F.; Fedotov, Yu.S.; Chepegin, V.N.; Chesnokov, Yu.A. [Institute for High Energy Physics, Protvino, Moscow oblast, 142284 (Russian Federation)

2005-06-01

357

Accelerator Configuration for Polarized Proton-Antiproton Physics at FAIR  

SciTech Connect

The HESR at FAIR is being designed to accelerate and store unpolarized antiprotons in the momentum range from 1.5 to 15 Ge V/c. Different scenarios are proposed to accelerate polarized proton and antiproton beams and finally store and collide them. In this paper required modifications and extensions of the accelerator layout are discussed and luminosity estimates presented.

Lehrach, Andreas [Forschungszentrum Juelich, Institut fuer Kernphysik, Postfach 1913, D-52425 Juelich (Germany)

2007-06-13

358

The Photon Collider  

NASA Astrophysics Data System (ADS)

The idea of converting an electron linear collider into a photon-photon collider through the addition of high power lasers was put forward in the early 1980s. Progress in the field of high average power, short pulse lasers has brought the state of the art within striking range of what would be required to realize a photon collider. In parallel, the necessary modifications to the detector and accelerator to enable a photon collider have been laid out. The basic concept of the photon collider, the requirements for the laser, and the detector and accelerator impact are reviewed in this article.

Gronberg, Jeffrey

2015-02-01

359

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

SciTech Connect

The purpose of this course is to provide a comprehensive introduction to the physics of beams with intense space charge. This course is suitable for graduate students and researchers interested in accelerator systems that require sufficient high intensity where mutual particle interactions in the beam can no longer be neglected. This course is intended to give the student a broad overview of the dynamics of beams with strong space charge. The emphasis is on theoretical and analytical methods of describing the acceleration and transport of beams. Some aspects of numerical and experimental methods will also be covered. Students will become familiar with standard methods employed to understand the transverse and longitudinal evolution of beams with strong space charge. The material covered will provide a foundation to design practical architectures. In this course, we will introduce you to the physics of intense charged particle beams, focusing on the role of space charge. The topics include: particle equations of motion, the paraxial ray equation, and the Vlasov equation; 4-D and 2-D equilibrium distribution functions (such as the Kapchinskij-Vladimirskij, thermal equilibrium, and Neuffer distributions), reduced moment and envelope equation formulations of beam evolution; transport limits and focusing methods; the concept of emittance and the calculation of its growth from mismatches in beam envelope and from space-charge non-uniformities using system conservation constraints; the role of space-charge in producing beam halos; longitudinal space-charge effects including small amplitude and rarefaction waves; stable and unstable oscillation modes of beams (including envelope and kinetic modes); the role of space charge in the injector; and algorithms to calculate space-charge effects in particle codes. Examples of intense beams will be given primarily from the ion and proton accelerator communities with applications from, for example, heavy-ion fusion, spallation neutron sources, nuclear waste transmutation, etc.

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

2008-05-30

360

EXTRACTION COMPRESSION AND ACCELERATION OF HIGH LINE CHARGE DENSITY ION BEAMS  

SciTech Connect

High Energy Density Physics (HEDP) applications require high line charge density ion beams. An efficient method to obtain this type of beams is to extract a long pulse, high current beam from a gun at high energy, and let the beam pass through a decelerating field to compress it. The low energy beam-bunch is loaded into a solenoid and matched to a Brillouin flow. The Brillouin equilibrium is independent of the energy if the relationship between the beam size (a), solenoid magnetic field strength (B) and line charge density is such that (Ba){sup 2} is proportional to the line charge density. Thus it is possible to accelerate a matched beam at constant line charge density. An experiment, NDCX-1c is being designed to test the feasibility of this type of injectors, where we will extract a 1 microsecond, 100 mA, potassium beam at 160 keV, decelerate it to 55 keV (density {approx}0.2 {micro}C/m), and load it into a 2.5 T solenoid where it will be accelerated to 100-150 keV (head to tail) at constant line charge density. The head-to-tail velocity tilt can be used to increase bunch compression and to control longitudinal beam expansion. We will present the physics design and numerical simulations of the proposed experiment.

Henestroza, Enrique; Henestroza, E.; Peters, C.; Yu, S.S.; Grote, D.P.; Briggs, R.J.

2005-05-20

361

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

SciTech Connect

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

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

2011-09-14

362

Interactive visualization of particle beams for accelerator design  

SciTech Connect

We describe a hybrid data-representation and rendering technique for visualizing large-scale particle data generated from numerical modeling of beam dynamics. The basis of the technique is mixing volume rendering and point rendering according to particle density distribution, visibility, and the user's instruction. A hierarchical representation of the data is created on a parallel computer, allowing real-time partitioning into high-density areas for volume rendering, and low-density areas for point rendering. This allows the beam to be interactively visualized while preserving the fine structure usually visible only with slow point based rendering techniques.

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

2002-01-15

363

A theory of ferromagnetic waveguide accelerators driven by an electron beam  

SciTech Connect

A fully self-consistent theory of ferromagnetic waveguide accelerators driven by a relativistic electron beam is developed. The theoretical analysis is based on Faraday's law, which provides a second-order partial-differential equation of the azimuthal magnetic field, under the assumption that [mu][epsilon][much gt]1. Here [mu] and [epsilon] are the permeability and dielectric constant of the waveguide material. The azimuthal magnetic field and axial acceleration field are obtained in forms of integral equations for an arbitrary profile of the drive-beam current [ital I]([ital t]). In the limit when the conductivity [sigma] of the waveguide material is zero, the acceleration mechanism is similar to the typical wake-field accelerators. In this limit, the acceleration field is proportional to the square root of the parameter [mu]/[epsilon] and can be easily more than 200 MV/m for moderate system parameters. On the other hand, for high conductivity limit, the acceleration mechanism is the magnetic field decay, exhibiting that the electromagnetic fields are a decaying function of the time. With appropriate physical parameters, the acceleration gradient of the magnetic field-decay accelerator is also very large.

Uhm, H.S. (Naval Surface Warfare Center, 10901 New Hampshire Ave., White Oak, Silver Spring, Maryland 20903-5000 (United States))

1993-03-01

364

Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider  

SciTech Connect

The concept of augmenting the conventional collimation system of high-energy storage rings with a hollow electron beam was successfully demonstrated in experiments at the Tevatron. A reliable numerical model is required for understanding particle dynamics in the presence of a hollow beam collimator. Several models were developed to describe imperfections of the electron beam profile and alignment. The features of the imperfections are estimated from electron beam profile measurements. Numerical simulations of halo removal rates are compared with experimental data taken at the Tevatron.

Morozov, I.A.; Stancari, G.; Valishev, A.; /Fermilab; Shatilov, D.N.; /Novosibirsk, IYF

2012-05-01

365

The Future of High Energy Polarized Proton Beams  

SciTech Connect

The acceleration and storage of high energy polarized proton beams has made tremendous progress over the last forty years challenging along the way the technologies, precision and the understanding of the beam dynamics of accelerators. This progress is most evident in that one can now contemplate high energy colliders with polarized beams and high luminosity at the same time. After a brief summary of the development and history of polarized proton beam acceleration the paper will focus on the highest energy polarized beams and the possibility of accelerating polarized beams to even higher energies in the future.

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

2009-08-04

366

PERFORMANCE LIMITATIONS IN HIGH-ENERGY ION COLLIDERS  

SciTech Connect

High-energy ion colliders (hadron colliders operating with ions other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams limits are set by space charge, charge exchange, and intrabeam scattering effects. The latter leads to luminosity lifetimes of only a few hours for intense heavy ions beams. Currently, the Relativistic Heavy Ion Collider (RHIC) at BNL is the only operating high-energy ion collider. Later this decade the Large Hadron Collider (LHC), under construction at CERN, will also run with heavy ions.

FISCHER, W.

2005-05-16

367

Start-to-end beam dynamics simulation of double triangular current profile generation in Argonne Wakefield Accelerator  

SciTech Connect

Double triangular current profile (DT) gives a high transformer ratio which is the determining factor of the performance of collinear wakefield accelerator. This current profile can be generated using the emittance exchange (EEX) beam line. Argonne Wakefield Accelerator (AWA) facility plans to generate DT using the EEX beam line. We conducted start-to-end simulation for the AWA beam line using PARMELA code. Also, we discuss requirements of beam parameters for the generation of DT.

Ha, G.; Power, J.; Kim, S. H.; Gai, W.; Kim, K.-J.; Cho, M. H.; Namkung, W. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of) and Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of) and Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 790-784 (Korea, Republic of)

2012-12-21

368

Low-Z gas stripper as an alternative to carbon foils for the acceleration of high-power uranium beams  

Microsoft Academic Search

The RIKEN accelerator complex started feeding the next-generation exotic beam facility radioisotope beam factory (RIBF) with heavy-ion beams from 2007 after the successful commissioning of RIBF at the end of 2006. Many improvements made from 2007 to 2010 were instrumental in increasing the intensity of various heavy-ion beams. However, the available beam intensity of very heavy ion beams, especially uranium

H. Okuno; N. Fukunishi; A. Goto; H. Hasebe; H. Imao; O. Kamigaito; M. Kase; H. Kuboki; Y. Yano; S. Yokouchi; A. Hershcovitch

2011-01-01

369

HIGH-ENERGY PARTICLE COLLIDERS: PAST 20 YEARS, NEXT 20 YEARS, AND BEYOND  

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 colliders has progressed immensely, while the beam energy, luminosity, facility size, and cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This paper briefly reviews the colliding beam method and the history of colliders, discusses the development of the method over the last two decades in detail, and examines near-term collider projects that are currently under development. The paper concludes with an attempt to look beyond the current horizon and to find what paradigm changes are necessary

Shiltsev, V.

2013-09-25

370

A superconducting quarter-wave resonator for high-brightness ion beam acceleration  

Microsoft Academic Search

A niobium resonant cavity optimized for phase velocity beta0 = 0.15 was constructed based on a coaxial quarter-wave geometry adapted for high-brightness ion beams. This cavity, which resonates at 400 MHz in the fundamental mode, operated at an average (wall-to-wall) accelerating gradient of 12.9 MV\\/m under continuous-wave fields. This is the highest average accelerating gradient achieved to date in low-velocity

J. R. Delayen; C. L. Bohn; C. T. Roche

1990-01-01

371

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

Microsoft Academic Search

The Continuous Electron Beam Accelerator Facility (CEBAF), under construction in Newport News, Virginia, is a particle accelerator laboratory for nuclear physics research funded by the U.S. Department of Energy. CEBAF's research and supporting technologies offer a rich environment for capturing the interest of and augmenting the experience of pre-college teachers and students. This paper describes some of the pre-college educational

Beverly Hartline; Kathryn Strozak

1992-01-01

372

Collision Technologies for Circular Colliders  

NASA Astrophysics Data System (ADS)

For several decades already, particle colliders have been essential tools for particle physics. From the very beginning, such accelerators have been among the most complicated scientific instruments ever built, including a number of innovative technological developments. Examples are ultrahigh vacuum systems, magnets with a very high magnetic field, and equipment for sub-ns synchronization and sub-mm precision alignment of equipment inside multi-km underground tunnels. Some key technologies are related to the focusing of the beam down to a scale of sub-?m at the collision point to obtain high luminosity. This review provides an overview of collision concepts and technologies for circular particle colliders, starting from the first ideas. In particular, it discusses such novel schemes and related technologies as crab waist collision and round beam collision.

Levichev, Eugene

2015-02-01

373

Crab Cavities for Linear Colliders  

SciTech Connect

Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

Burt, G.; Ambattu, P.; Carter, R.; Dexter, A.; Tahir, I.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Beard, C.; Dykes, M.; Goudket, P.; Kalinin, A.; Ma, L.; McIntosh, P.; /Daresbury; Shulte, D.; /CERN; Jones, Roger M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Bellantoni, L.; Chase, B.; Church, M.; Khabouline, T.; Latina, A.; /Fermilab; Adolphsen, C.; Li, Z.; Seryi, Andrei; /SLAC

2011-11-08

374

Summary II - Fusion Ion sources, Beam Formation, Acceleration and Neutralisation  

SciTech Connect

The 11th International Symposium on the Production and Neutralization of Negative Ions and Beams was held in Santa Fe, New Mexico on 13th - 15th September 2006 and was hosted by Los Alamos National Laboratory. This summary covers the sessions of the Symposium devoted to the topics listed in the title.

Jones, T. T. C. [UKAEA Culham Division, Abingdon, OX14 3DB (United Kingdom)

2007-08-10

375

Plasmas in particle accelerators: adiabatic theories for bunched beams  

SciTech Connect

Three different formalisms for discussing Vlasov's equation for bunched beam problems with anharmonic space charge forces are outlined. These correspond to the use of a drift kinetic equation averaged over random betatron motions; a fluidkinetic adiabatic regime analogous to the theory of Chew, Goldberger, and Low; and an adiabatic hydrodynamic theory.

Mark, J.W.K.

1981-03-03

376

Long-pulse beam stability experiments on the DARHT-II linear induction accelerator  

Microsoft Academic Search

When completed, the DARHT-II linear induction accelerator (LIA) will produce a 2-kA, 17-MeV electron beam in a 1600-ns flat-top pulse. In initial tests, DARHT-II accelerated beams with current pulse lengths from 500 to 1200 ns full-width at half-maximum (FWHM) with more than 1.2-kA, 12.5-MeV peak current and energy. Experiments have now been done with a ?1600-ns pulse length. These pulse

Carl Ekdahl; E. O. Abeyta; P. Aragon; R. Archuleta; R. Bartsch; H. Bender; R. Briggs; W. Broste; C. Carlson; K. C. D. Chan; D. Dalmas; S. Eversole; D. Frayer; R. Gallegos; J. Harrison; T. Hughes; E. Jacquez; D. Johnson; J. Johnson; B. Trent McCuistian; N. Montoya; C. Mostrom; S. Nath; D. Oro; L. Rowton; M. Sanchez; R. Scarpetti; M. Schauer; M. Schulze; Y. Tang; A. Tipton; C. Y. Tom

2006-01-01

377

Tunable monoenergetic electron beams from independently controllable laser-wakefield acceleration and injection  

NASA Astrophysics Data System (ADS)

We report the results of experiments on laser-wakefield acceleration in a novel two-stage gas target with independently adjustable density and atomic-composition profiles. We were able to tailor these profiles in a way that led to the separation of the processes of electron injection and acceleration and permitted independent control of both. This resulted in the generation of stable, quasimonoenergetic electron beams with central energy tunable in 50-300 MeV range. For the first time, we are able to independently control the beam charge and energy spread over the entire tunability range.

Golovin, G.; Chen, S.; Powers, N.; Liu, C.; Banerjee, S.; Zhang, J.; Zeng, M.; Sheng, Z.; Umstadter, D.

2015-01-01

378

Generating Overcritical Dense Relativistic Electron Beams via Self-Matching Resonance Acceleration  

NASA Astrophysics Data System (ADS)

We show a novel self-matching resonance acceleration regime for generating dense relativistic electron beams by using ultraintense circularly polarized laser pulses in near-critical density plasmas. When the self-generated quasistatic axial magnetic field is strong enough to pinch and trap thermal relativistic electrons, an overdense electron bunch is formed in the center of the laser channel. In the trapping process, the electron betatron frequencies and phases can be adjusted automatically to match the resonance condition. The matched electrons are accelerated continuously and a collimated electron beam with overcritical density, helical structure, and plateau profile energy spectrum is hence generated.

Liu, B.; Wang, H. Y.; Liu, J.; Fu, L. B.; Xu, Y. J.; Yan, X. Q.; He, X. T.

2013-01-01

379

Induction-accelerator heavy-ion fusion: Status and beam physics issues  

SciTech Connect

Inertial confinement fusion driven by beams of heavy ions is an attractive route to controlled fusion. In the U.S., induction accelerators are being developed as {open_quotes}drivers{close_quotes} for this process. This paper is divided into two main sections. In the first section, the concept of induction-accelerator driven heavy-ion fusion is briefly reviewed, and the U.S. program of experiments and theoretical investigations is described. In the second, a {open_quotes}taxonomy{close_quotes} of space-charge-dominated beam physics issues is presented, accompanied by a brief discussion of each area.

Friedman, A.

1996-01-26

380

Collective acceleration of electrons and ions in a high current relativistic electron beam. Final report  

SciTech Connect

The original purpose of this research was an investigation into the use of slow space charge waves on weakly relativistic electron beams for ion acceleration. The work had three main objectives namely, the development of a suitable ion injector, the growth and study of the properties of slow space charge waves on an electron beam, and a combination of the two components parts into a suitable proof of principle demonstration of the wave accelerator. This work focusses on the first two of these objectives.

Nation, J.A.

1996-12-31

381

Analytical solutions for transient and steady state beam loading in arbitrary traveling wave accelerating structures  

SciTech Connect

Analytical solutions are derived for both transient and steady state gradient distributions in the traveling wave (TW) accelerating structures with arbitrary variation of parameters over the structure length. The results of the unloaded and beam loaded cases are presented. Finally, the exact analytical shape of the rf pulse waveform was found in order to apply the transient beam loading compensation scheme during the structure filling time. The obtained theoretical formulas were cross-checked by direct numerical simulations on the CLIC main linac accelerating structure and demonstrated a good agreement. The proposed methods provide a fast and reliable tool for the initial stage of the TW structure analysis.

Lunin, A.; Yakovlev, V.; /Fermilab; Grudiev, A.; /CERN

2011-05-02

382

Laser and electron beam propagation and stability in laser wakefield accelerators  

NASA Astrophysics Data System (ADS)

Presented here are recent experimental and simulation results on laser and electron beam propagation and stability in laser wakefield accelerators (LWFAs) using the HERCULES laser. By using various gas jet nozzles with opening diameters ranging from 0.5 to 5 mm, electron injection, acceleration and laser propagation were studied. Electron beams produced in plasma channels significantly longer than the laser depletion length were observed to break into a number of filaments. This is likely due to a current filamentation instability as the electron beam propagates through unperturbed plasma after pump depletion. Experiments and simulations also reveal that stimulated Raman side scattering occurs at the beginning of the interaction, that it contributes to the evolution of the pulse prior to wakefield formation, and that it affects the quality of electron beams generated.

Thomas, Alec; Huntington, C.; McGuffey, C.; Bulanov, S.; Cummings, P.; Chvykov, V.; Dollar, F.; Drake, P.; Horovitz, Y.; Kalintchenko, G.; Krushelnick, K.; Maksimchuk, A.; Matsuoka, T.; Rousseau, P.; Yanovsky, V.; Kneip, S.; Mangles, S.; Najmudin, Z.; Palmer, C.

2010-11-01

383

Accelerator and Ion Beam Tradeoffs for Studies of Warm Dense Matter  

SciTech Connect

One approach for heating a target to ''Warm Dense Matter'' conditions (similar, for example, to the interiors of giant planets or certain stages in Inertial Confinement Fusion targets), is to use intense ion beams as the heating source (see refs.[6] and [7] and references therein for motivation and accelerator concepts). By consideration of ion beam phase space constraints, both at the injector, and at the final focus, and consideration of simple equations of state and relations for ion stopping, approximate conditions at a target foil may be calculated. Thus target temperature and pressure may be calculated as a function of ion mass, ion energy, pulse duration, velocity tilt, and other accelerator parameters. We connect some of these basic parameters to help search the extensive parameter space (including ion mass, ion energy, total charge in beam pulse, beam emittance, target thickness and density).

Barnard, J J; Briggs, R J; Callahan, D A; Davidson, R C; Friedman, A; Grisham, L; Lee, E P; Lee, R W; Logan, B G; Olson, C L; Rose, D V; Santhanam, P; Sessler, A M; Staples, J W; Tabak, M; Welch, D R; Wurtele, J S; Yu, S S

2005-05-13

384

Accelerator and Ion Beam Tradeoffs for Studies of Warm DenseMatter  

SciTech Connect

One approach for heating a target to ''Warm Dense Matter'' conditions (similar, for example, to the interiors of giant planets or certain stages in inertial confinement fusion targets), is to use intense ion beams as the heating source (see refs.[6] and [7] and references therein for motivation and accelerator concepts). By consideration of ion beam phase-space constraints, both at the injector, and at the final focus, and consideration of simple equations of state and relations for ion stopping, approximate conditions at the target foil may be calculated. Thus, target temperature and pressure may be calculated as a function of ion mass, ion energy, pulse duration, velocity tilt, and other accelerator parameters. We connect some of these basic parameters to help search the extensive parameter space including ion mass, ion energy, total charge in beam pulse, beam emittance, target thickness and density.

Barnard, J.J.; Briggs, R.J.; Callahan, D.A.; Davidson, R.C.; Friedman, A.; Grisham, L.; Lee, E.P.; Lee, R.W.; Logan, B.G.; Olson,C.L.; Rose, D.V.; Santhanam, P.; Sessler, A.M.; Staples, J.W.; Tabak, M.; Welch, D.R.; Wurtele, J.S.; Yu, S.S.

2006-01-30

385

Beam test of a new radio frequency quadrupole linac for the Japan Proton Accelerator Research Complex  

NASA Astrophysics Data System (ADS)

We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.

Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saisyun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuta, Shinpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; Koizumi, Isao; Miura, Akihiko; Oguri, Hidetomo; Ohkoshi, Kiyonori; Sato, Fumiaki; Shinozaki, Shinichi; Ueno, Akira; Kawamata, Hiroshi; Sugimura, Takashi; Takagi, Akira; Fang, Zhigao; Fukui, Yuji; Futatsukawa, Kenta; Ikegami, Kiyoshi; Maruta, Tomofumi; Miyao, Tomoaki; Nanmo, Kesao

2014-12-01

386

First simultaneous measurement of sextupolar and octupolar resonance driving terms in a circular accelerator from turn-by-turn beam position monitors data  

E-print Network

Beam lifetime in storage rings and colliders is affected by, among other effects, lattice nonlinearities. Their control are of great benefit to the dynamic aperture of an accelerator, whose enlargement leads in general to more efficient injection and longer lifetime. This article describes a procedure to evaluate and correct unwanted nonlinearities by using turn-by-turn beam position monitor data, which is an evolution of previous works on the resonance driving terms (RDTs). Effective sextupole magnetic errors and tilts at the ESRF electron storage ring are evaluated and corrected (when possible) by using this technique. For the first time, also octupolar RDTs could be measured and used to define an octupolar model for the main quadrupoles. Most of the deviations from the model observed in the sextupolar RDTs of the ESRF storage ring turned out to be generated by focusing errors rather than by sextupole errors. These results could be achieved thanks to new analytical formulas describing the harmonic content o...

Franchi, A; Ewald, F; Bec, G Le; Scheidt, K B

2014-01-01

387

High-quality electron beams from a helical inverse free-electron laser accelerator  

NASA Astrophysics Data System (ADS)

Compact, table-top sized accelerators are key to improving access to high-quality beams for use in industry, medicine and academic research. Among laser-based accelerating schemes, the inverse free-electron laser (IFEL) enjoys unique advantages. By using an undulator magnetic field in combination with a laser, GeV?m?1 gradients may be sustained over metre-scale distances using laser intensities several orders of magnitude less than those used in laser wake-field accelerators. Here we show for the first time the capture and high-gradient acceleration of monoenergetic electron beams from a helical IFEL. Using a modest intensity (~1013?W?cm?2) laser pulse and strongly tapered 0.5?m long undulator, we demonstrate >100?MV?m?1 accelerating gradient, >50?MeV energy gain and excellent output beam quality. Our results pave the way towards compact, tunable GeV IFEL accelerators for applications such as driving soft X-ray free-electron lasers and producing ?-rays by inverse Compton scattering.

Duris, J.; Musumeci, P.; Babzien, M.; Fedurin, M.; Kusche, K.; Li, R. K.; Moody, J.; Pogorelsky, I.; Polyanskiy, M.; Rosenzweig, J. B.; Sakai, Y.; Swinson, C.; Threlkeld, E.; Williams, O.; Yakimenko, V.

2014-09-01

388

High-quality electron beams from a helical inverse free-electron laser accelerator.  

PubMed

Compact, table-top sized accelerators are key to improving access to high-quality beams for use in industry, medicine and academic research. Among laser-based accelerating schemes, the inverse free-electron laser (IFEL) enjoys unique advantages. By using an undulator magnetic field in combination with a laser, GeV m(-1) gradients may be sustained over metre-scale distances using laser intensities several orders of magnitude less than those used in laser wake-field accelerators. Here we show for the first time the capture and high-gradient acceleration of monoenergetic electron beams from a helical IFEL. Using a modest intensity (~10(13)?W cm(-2)) laser pulse and strongly tapered 0.5 m long undulator, we demonstrate >100 MV m(-1) accelerating gradient, >50 MeV energy gain and excellent output beam quality. Our results pave the way towards compact, tunable GeV IFEL accelerators for applications such as driving soft X-ray free-electron lasers and producing ?-rays by inverse Compton scattering. PMID:25222026

Duris, J; Musumeci, P; Babzien, M; Fedurin, M; Kusche, K; Li, R K; Moody, J; Pogorelsky, I; Polyanskiy, M; Rosenzweig, J B; Sakai, Y; Swinson, C; Threlkeld, E; Williams, O; Yakimenko, V

2014-01-01

389

Potential-Well Distortion, Microwave Instability, and Their Effects with Colliding Beams at KEKB  

SciTech Connect

Microwave instability in the Low Energy Ring of KEKB was studied using a broadband impedance model. The model gave excellent descriptions of longitudinal dynamics for both positive and negative momentum compactions. Moreover, it predicted that the threshold of microwave instability was a factor of two lower than the machine nominal operating bunch current. The prediction was confirmed by a measurement using the Belle detector. Furthermore, we integrated the longitudinal wakefield into the beam-beam simulation and applied it to study the combined effects in KEKB. As a result, the beam-beam simulation became truly three-dimensional with emittance growth in all three dimensions simultaneously as the beam currents increase. In addition, an observed mystery of asymmetry in the horizontal scan could also be explained by our simulations.

Cai, Yunhai; /SLAC; Flanagan, J.; Fukuma, H.; Funakoshi, Y.; Ieiri, T.; Ohmi, K.; Oide, K.; Suetsugu, Y.; /KEK, Tsukuba; Rorie, Jamal; /Hawaii U.

2009-04-01

390

Effects of misaligned electron beam on inverse free electron laser acceleration  

NASA Astrophysics Data System (ADS)

In this paper, we discuss the effects of misaligned electron beam on an inverse free electron laser with both an electromagnetic wave wiggler and magnetostatic wiggler acceleration scheme. It is shown analytically that electromagnetic wiggler IFEL energy gain distance is substantially smaller when compared to the standard IFEL i.e. with a magnetostatic wiggler. The analysis further explains a better tolerance of the electromagnetic wiggler IFEL with respect to the misaligned electron beam in comparison to a magnetostatic wiggler IFEL scheme.

Khullar, Roma; Sharma, Geetanjali; Mishra, G.

2015-02-01

391

Narrowband beam loading compensation in the Fermilab Main Injector accelerating cavities  

SciTech Connect

A narrowband beam loading compensation system was installed for the Main Injector Accelerating Cavities. This feedback operates solely on the fundamental resonant mode of the cavity. This paper describes modifications to the high level Radio Frequency system required to make the system operational. These modifications decreased the effect of steady-state beam loading by a factor of 10 and improved the reliability of paraphasing for coalescing.

Joseph E. Dey; John S. Reid and James Steimel

2001-07-12

392

Muon Collider  

SciTech Connect

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

Palmer, R.

2009-10-19

393

The modeling of a linear multi-beam deuteron compact accelerator for neutron generation  

NASA Astrophysics Data System (ADS)

There is a prominent interest in obtaining high-flux neutron generators due to its wide range of applications and possibilities. The beam current that reaches the target is one of the main factors for determining the performance of the generator. In the present paper we address the modeling of a deuteron compact accelerator for neutron generation underlying the electrode placement and providing an optimized multiple beam accelerator geometry. The methodology consists of electrode displacement calculations and simulations of the deuteron and neutron beam transport. A phenomenological model has been proposed based on experimental data, which provides two electrode configuration patterns. Both configurations were compared through electromagnetic simulations considering a single-beam accelerator-type. The configuration with highest ion current has led to a new geometry incorporating multiple beams. The final prototype presents an interesting beam profile achieving deuteron kinetic energy in the order of 180 keV and current up to 198 mA. Estimated yield for this generator was 1012 n/s. A shield was designed, based on Monte Carlo simulations. Dose calculation was appraised showing a neutron and photon dose rate of 7.73 and 14.50 mGy h-1 in front of 46 cm shield. The achieved design offers a suitable performance toward a compact high-flux neutron generator.

Araujo, Wagner L.; Campos, Tarcisio P. R.

2012-07-01

394

Beam Transport in a Compact Dielectric Wall Accelerator for Proton Therapy  

SciTech Connect

To attain the highest accelerating gradient in the compact dielectric wall (DWA) accelerator, the DWA will be operated in the 'virtual' traveling mode with potentially non-uniform and time-dependent axial accelerating field profiles, especially near the DWA entrance and exit, which makes beam transport challenging. We have established a baseline transport case without using any external lenses. Results of simulations using the 3-D, EM PIC code, LSP indicate that the DWA transport performance meets the medical specifications for proton treatment. Sensitivity of the transport performance to Blumlein block failure will be presented.

Chen, Y; Caporaso, G; Blackfield, D; Nelson, S D; Poole, B

2011-03-16

395

2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe  

SciTech Connect

A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

Chen, Y. H.; Yang, X. Y.; Lin, C., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn; Wang, X. G.; Xiao, C. J., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn [State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wang, L. [Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China); Xu, M. [Center for Fusion Science of Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041 (China)

2014-11-15

396

2D electron density profile measurement in tokamak by laser-accelerated ion-beam probea)  

NASA Astrophysics Data System (ADS)

A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

Chen, Y. H.; Yang, X. Y.; Lin, C.; Wang, L.; Xu, M.; Wang, X. G.; Xiao, C. J.

2014-11-01

397

A new version of a free electron laser Two-Beam Accelerator  

SciTech Connect

A new version of a Two-Beam Accelerator is proposed in which in each period of the drive structure a very small input microwave signal is amplified to a large power level and then completely removed and transferred to the accelerating structure. In this manner a number of difficulties with the original version are eliminated or greatly relieved; namely, rf phase and amplitude sensitivity, growth of sidebands, and rf manipulation (removal of the microwaves from the drive structure, and transmission of microwave power through the accelerating cavities). 11 refs., 6 figs., 2 tabs.

Sessler, A.M.; Sternbach, E.; Wurtele, J.S.

1988-09-01

398

Plasmas in particle accelerators: the warm-beam equilibria  

SciTech Connect

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

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

1981-04-07

399

Trends and applications for MeV electrostatic ion beam accelerators  

NASA Astrophysics Data System (ADS)

The 1970s into the 1980s saw a major broadening of applications for electrostatic accelerators. Prior to this time, all accelerators were used primarily for nuclear structure research. In the 70s there was a significant move into production ion implantation with the necessary MeV ion beam analysis techniques such as RBS and ERD. Accelerators are still being built for these materials analysis techniques today. However, there is still a great ongoing expansion of applications for these machines. At the present time, the demand for electrostatic accelerators is near an all time high. The number of applications continues to grow. This paper will touch on some of the current applications which are as diverse as nuclear fission reactor developments and pharmacokinetics. In the field of nuclear engineering, MeV ion beams from electrostatic accelerators are being used in material damage studies and for iodine and actinide accelerator mass spectrometry (AMS). In the field of pharmacokinetics, electrostatic MeV accelerators are being used to detect extremely small amounts of above background 14C. This has significantly reduced the time required to reach first in human studies. These and other applications will be discussed.

Norton, G. A.; Stodola, S. E.

2014-08-01

400

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

SciTech Connect

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

Briggs, R.J.

1989-02-15

401

ACCELERATOR OPERATIONS AND TECHNOLOGY DIVISION AOT-ABS Accelerator and Beam Science  

E-print Network

Crady Poster Title: Application of Independent Component Analysis (ICA) to Long Bunch Beams in the Los Alamos System Studies of Cellulose Conversion to Biofuel via Garcia-Gonzalez Reaction Name: Alex Koglin

402

Ultrafast Diagnostics for Electron Beams from Laser Plasma Accelerators  

SciTech Connect

We present an overview of diagnostic techniques for measuring key parameters of electron bunches from Laser Plasma Accelerators (LPAs). The diagnostics presented here were chosen because they highlight the unique advantages (e.g., diverse forms of electromagnetic emission) and difficulties (e.g., shot-to-shot variability) associated with LPAs. Non destructiveness and high resolution (in space and time and energy) are key attributes that enable the formation of a comprehensive suite of simultaneous diagnostics which are necessary for the full characterization of the ultrashort, but highly-variable electron bunches from LPAs.

Matlis, N. H.; Bakeman, M.; Geddes, C. G. R.; Gonsalves, T.; Lin, C.; Nakamura, K.; Osterhoff, J.; Plateau, G. R.; Schroeder, C. B.; Shiraishi, S.; Sokollik, T.; van Tilborg, J.; Toth, Cs.; Leemans, W. P.

2010-06-01

403

High-quality electron beams from beam-driven plasma accelerators by wakefield-induced ionization injection.  

PubMed

We propose a new and simple strategy for controlled ionization-induced trapping of electrons in a beam-driven plasma accelerator. The presented method directly exploits electric wakefields to ionize electrons from a dopant gas and capture them into a well-defined volume of the accelerating and focusing wake phase, leading to high-quality witness bunches. This injection principle is explained by example of three-dimensional particle-in-cell calculations using the code OSIRIS. In these simulations a high-current-density electron-beam driver excites plasma waves in the blowout regime inside a fully ionized hydrogen plasma of density 5×10(17)cm-3. Within an embedded 100???m long plasma column contaminated with neutral helium gas, the wakefields trigger ionization, trapping of a defined fraction of the released electrons, and subsequent acceleration. The hereby generated electron beam features a 1.5 kA peak current, 1.5???m transverse normalized emittance, an uncorrelated energy spread of 0.3% on a GeV-energy scale, and few femtosecond bunch length. PMID:24483670

Martinez de la Ossa, A; Grebenyuk, J; Mehrling, T; Schaper, L; Osterhoff, J

2013-12-13

404

Proceedings of the workshop on prospects for research with radioactive beams from heavy ion accelerators  

SciTech Connect

The SuperHILAC Users Executive Committee organized a workshop on Prospects for Research with Radioactive Beams from Heavy Ion Accelerators. The main purpose of the workshop was to bring together a diverse group of scientists who had already done experients with radioactive beams or were interested in their use in the future. The topics of the talks ranged from general nuclear physics, astrophysics, production of radioactive beams and high energy projectile fragmentation to biomedical applications. This publication contains the abstracts of the talks given at the workshop and copies of the viewgraphs as they were supplied to the editor.

Nitschke, J.M. (ed.)

1984-04-01

405

Collimated electron beam accelerated at 12 kV from a Penning discharge  

NASA Astrophysics Data System (ADS)

A pulsed electron beam accelerated at 12 kV with a duration of 40 ?s per pulse is obtained from a Penning discharge with a hollow anode and two cathodes. The electrons are extracted through a hole in one of the cathodes and focused by a pair of coils. The electron beam has a diameter of a few mm in the cross section, while the beam current reaches peak values of 400 mA, depending on the magnetic field inside the focussing coils. This relatively inexpensive and compact device is suitable for the irradiation of small material samples placed in high vacuum.

Toader, D.; Oane, M.; Tico?, C. M.

2015-01-01

406

Collimated electron beam accelerated at 12 kV from a Penning discharge.  

PubMed

A pulsed electron beam accelerated at 12 kV with a duration of 40 ?s per pulse is obtained from a Penning discharge with a hollow anode and two cathodes. The electrons are extracted through a hole in one of the cathodes and focused by a pair of coils. The electron beam has a diameter of a few mm in the cross section, while the beam current reaches peak values of 400 mA, depending on the magnetic field inside the focussing coils. This relatively inexpensive and compact device is suitable for the irradiation of small material samples placed in high vacuum. PMID:25638079

Toader, D; Oane, M; Tico?, C M

2015-01-01

407

Matching the rf quadrupole beam to the drift-tube section in the FMIT accelerator  

SciTech Connect

The beam produced by the Fusion Materials Irradiation Test (FMIT) radio frequency quadrupole (RFQ) accelerating structure must be matched to the drift-tube linac (DTL) structure that follows. Because minimum beam spill is a primary concern, a matching criterion that considers the beam edges as well as the rms properties is needed. We flared the RFQ's vanes and adjusted the strengths of the first four quadrupoles in the DTL to achieve optimum performance downstream. Numerical methods used to set the quad gradients, and some experience with various matching criteria are described. The match achieved is compared with matches obtained by other methods.

Boicourt, G.P.; Jameson, R.A.; Mills, R.S.

1981-01-01

408

Development and beam test of a continuous wave radio frequency quadrupole accelerator  

NASA Astrophysics Data System (ADS)

The front end of any modern ion accelerator includes a radio frequency quadrupole (RFQ). While many pulsed ion linacs successfully operate RFQs, several ion accelerators worldwide have significant difficulties operating continuous wave (CW) RFQs to design specifications. In this paper we describe the development and results of the beam commissioning of a CW RFQ designed and built for the National User Facility: Argonne Tandem Linac Accelerator System (ATLAS). Several innovative ideas were implemented in this CW RFQ. By selecting a multisegment split-coaxial structure, we reached moderate transverse dimensions for a 60.625-MHz resonator and provided a highly stabilized electromagnetic field distribution. The accelerating section of the RFQ occupies approximately 50% of the total length and is based on a trapezoidal vane tip modulation that increased the resonator shunt impedance by 60% in this section as compared to conventional sinusoidal modulation. To form an axially symmetric beam exiting the RFQ, a very short output radial matcher with a length of 0.75?? was developed. The RFQ is designed as a 100% oxygen-free electronic (OFE) copper structure and fabricated with a two-step furnace brazing process. The radio frequency (rf) measurements show excellent rf properties for the resonator, with a measured intrinsic Q equal to 94% of the simulated value for OFE copper. An O5+ ion beam extracted from an electron cyclotron resonance ion source was used for the RFQ commissioning. In off-line beam testing, we found excellent coincidence of the measured beam parameters with the results of beam dynamics simulations performed using the beam dynamics code TRACK, which was developed at Argonne. These results demonstrate the great success of the RFQ design and fabrication technology developed here, which can be applied to future CW RFQs.

Ostroumov, P. N.; Mustapha, B.; Barcikowski, A.; Dickerson, C.; Kolomiets, A. A.; Kondrashev, S. A.; Luo, Y.; Paskvan, D.; Perry, A.; Schrage, D.; Sharamentov, S. I.; Sommer, R.; Toter, W.; Zinkann, G.

2012-11-01

409

Multi- TeV Collider Booster  

NASA Astrophysics Data System (ADS)

We suggest a unique potential that existing high energy lepton colliders serve as a booster for a multi-TeV collider based on the electron beam-driven plasma wakefield acceleration. This booster acceleration can easily provide multi-tens of GeV/m acceleration gradient over a focal length of meters. The TeV range energy can then be achieved in several tens of stages with a combined length of the order of 100 m. We have identified two of the most crucial physics issues for this acceleration. One is the emittance degradation by the strong wakefield focus over multiple stages. The other is the electron hose instability which might disrupt the driver beam. A systematic study on these issues taking into account general constraints on beam parameters (Xie et al., Advanced Accelerator Concepts 7, ed. S. Chattopadhyay (AIP, New York 1997), p.233-242.) will be reported. In addition, we also investigate the effect of multiple scattering in the plasma on the trailing beam emittance. The work is supported by US DoE.

Chen, P.; Cheshkov, S.; Ruth, R.; Tajima, T.

1999-11-01

410

Ti foil light in the ATA (Advanced Test Accelerator) beam  

SciTech Connect

An experiment is in progress to characterize the visible light produced when a Ti foil is immersed in the ATA 2 kA, 43 MeV beam. Results obtained to date indicate that the optical condition of the foil surface is a critical determinant of these characteristics, with a very narrow angular distribution obtained when a highly polished and flat foil is used. These data are consistent with the present hypothesis that the light is produced by transition radiation. Incomplete experiments to determine the foil angle dependence of the detected light and its polarization are summarized and remaining experiments are described.

Slaughter, D.R.; Chong, Y.P.; Goosman, D.R.; Rule, D.W.; Fiorito, R.B.

1987-09-01

411

Reconstruction of Initial Beam Conditions at the Exit of the DARHT II Accelerator  

NASA Astrophysics Data System (ADS)

We consider a technique to determine the initial beam conditions of the DARHT II Accelerator by measuring the beam size under three different magnetic transport settings. This may be time gated to resolve the parameters as a function of time within the 2000 nsec pulse. This technique leads to three equations in three unknowns with solution giving the accelerator exit beam radius, tilt and emittance. We find that systematic errors cancel and so are not a problem in unfolding the initial beam conditions. Random uncorrelated shot to shot errors can be managed by one of three strategies: 1) make the transport system optically de-magnifying; 2) average over many individual shots; or 3) make the random uncorrelated shot to shot errors sufficiently small. The high power of the DARHT II beam requires that the beam transport system leading to a radius measuring apparatus be optically magnifying. This means that the shot to shot random errors must either be made small (less than about 1%) or that we average each of the three beam radius determinations over many individual shots.

Paul, Arthur

412

Surface acoustic wave acceleration sensor with high sensitivity incorporating ST-X quartz cantilever beam  

NASA Astrophysics Data System (ADS)

The implementation and performance of a surface acoustic wave (SAW)-based acceleration sensor is described. The sensor was composed of a flexible ST-X quartz cantilever beam with a relatively substantial proof mass at the undamped end, a pattern of a two-port SAW resonator deposited directly on the surface of the beam adjacent to the clamped end for maximum strain sensitivity and a SAW resonator affixed on the metal package base for temperature compensation. The acceleration was directed to the proof mass flex of the cantilever, inducing relative changes in the acoustic propagation characteristics of the SAW traveling along the beams. The frequency signal from the differential oscillation structure utilizing the SAW resonators as the feedback element varies as a function of acceleration. The sensor response mechanism was analyzed theoretically, with the aim of determining the optimized dimension of the cantilever beam. The coupling of modes (COM) model was used to simulate the synchronous SAW resonator prior to fabrication. The oscillator frequency stability was improved using the phase modulation approach; the obtained typical short-term frequency stability ranged up to 1 Hz s?1. The performance of the developed acceleration sensor was evaluated using the precise vibration table and was also evaluated in comparison to the theoretical calculation. A high frequency sensitivity of 29.7 kHz g?1, good linearity and a lower detection limit (˜1 × 10?4 g) were achieved in the measured results.

Wang, Wen; Huang, Yangqing; Liu, Xinlu; Liang, Yong

2015-01-01

413

3D particle simulations of space-charge-dominated beams in HIF accelerator experiments  

SciTech Connect

The development of a high current, heavy-ion beam for inertial confinement fusion requires a detailed understanding of the behavior of the beam, including effects of the large self-fields. This necessity makes particle-in-cell (PIC) simulation the appropriate tool, and for this reason, the three-dimensional PIC/accelerator code WARP3d is being developed. WARP3d has been used extensively to study the creation and propagation of ion beams both to support experiments and for the understanding of basic beam physics. An overview of the structure of the code is presented along with a discussion of features that make the code an effective tool in the understanding of space-charge dominated beam behavior. A number of applications where WARP3d has played an important role is discussed, emphasizing the need of three-dimensional, first principles simulations. Results and comparisons with experiment are presented.

Grote, D.P.; Friedman, A.; Lund, S.M. [Lawrence Livermore National Lab., CA (United States); Haber, I. [Naval Research Lab., Washington, DC (United States)

1997-05-01

414

Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center  

SciTech Connect

A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

S. Setiniyaz, T.A. Forest, K. Chouffani, Y. Kim, A. Freyberger

2012-07-01

415

Spectrum bandwidth narrowing of Thomson scattering X-rays with energy chirped electron beams from laser wakefield acceleration  

SciTech Connect

We study incoherent Thomson scattering between an ultrashort laser pulse and an electron beam accelerated from a laser wakefield. The energy chirp effects of the accelerated electron beam on the final radiation spectrum bandwidth are investigated. It is found that the scattered X-ray radiation has the minimum spectrum width and highest intensity as electrons are accelerated up to around the dephasing point. Furthermore, it is proposed that the electron acceleration process inside the wakefield can be studied by use of 90° Thomson scattering. The dephasing position and beam energy chirp can be deduced from the intensity and bandwidth of the scattered radiation.

Xu, Tong; Chen, Min, E-mail: minchen@sjtu.edu.cn; Li, Fei-Yu; Yu, Lu-Le [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Sheng, Zheng-Ming, E-mail: zmsheng@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Zhang, Jie [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)

2014-01-06

416

Twin Symmetric E-plane Slab Loaded Waveguide Structure for Point Beam Acceleration  

NASA Astrophysics Data System (ADS)

Renewed interest regarding the exploitation of dielectric loaded waveguides in high gradient accelerator structures requires a closed form field formulation as cut-off frequencies and optimisation are problematic for numerical methods. In this paper we will present efficient closed form solution for generic slab loaded waveguide boundary value problems. This solution offers flexibility in a sense that it can be further exploited to derive a Green’s function linking transverse field expressions for planar structures. The developed solution is demonstrated for a twin slab E-plane slab loaded structure coupled to a Point source emitter assembly. The emission characteristics of the point source emitter assembly are optimized to generate a high intensity and focused beam to be fed to this E-plane slab loaded waveguide structure for beam acceleration. The field analysis, mode nomenclature, modal hierarchy, modal bandwidth, cut-off plane, impedance plane and dispersion relations for this accelerating structure is included for sake the of completeness.

Zafar, H.; Zafar, J.; Gibson, A. A. P.; Masood, K.

2009-02-01

417

Stable laser-driven proton beam acceleration from a two-ion-species ultrathin foil.  

PubMed

By using multidimensional particle-in-cell simulations, we present a new regime of stable proton beam acceleration which takes place when a two-ion-species shaped foil is illuminated by a circularly polarized laser pulse. In the simulations, the lighter protons are nearly instantaneously separated from the heavier carbon ions due to the charge-to-mass ratio difference. The heavy ion layer expands in space and acts to buffer the proton layer from the Rayleigh-Taylor-like (RT) instability that would have otherwise degraded the proton beam acceleration. A simple three-interface model is formulated to explain qualitatively the stable acceleration of the light ions. In the absence of the RT instability, the high quality monoenergetic proton bunch persists even after the laser-foil interaction ends. PMID:20867984

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

2010-08-01

418

Analyses of high power negative ion accelerators for ITER neutral beam injector (invited).  

PubMed

In JAEA, research and developments to realize high power accelerator (1 MeV, 40 AD(-) ion beams for 3600 s) for ITER have been carried out experimentally and numerically utilizing a five stage MAMuG (Multiaperture, Multigrid) accelerator. In this paper, the extension of the gap length, which is required to improve the voltage holding capability, is examined in two dimensional beam optics analyses and also from view point of stripping loss of ions. In order to suppress excess power loadings due to the direct interception of negative ions, which is issued in long pulse tests, the beamlet deflection is analyzed in three dimensional multibeamlet analyses. The necessary modifications shown above are applied to the MAMuG accelerator for coming long pulse tests in JAEA and ITER. PMID:20192419

Kashiwagi, M; Taniguchi, M; Dairaku, M; Grisham, L R; Hanada, M; Mizuno, T; Tobari, H; Umeda, N; Watanabe, K; Sakamoto, K; Inoue, T

2010-02-01

419

Analyses of high power negative ion accelerators for ITER neutral beam injector (invited)a)  

NASA Astrophysics Data System (ADS)

In JAEA, research and developments to realize high power accelerator (1 MeV, 40 AD- ion beams for 3600 s) for ITER have been carried out experimentally and numerically utilizing a five stage MAMuG (Multiaperture, Multigrid) accelerator. In this paper, the extension of the gap length, which is required to improve the voltage holding capability, is examined in two dimensional beam optics analyses and also from view point of stripping loss of ions. In order to suppress excess power loadings due to the direct interception of negative ions, which is issued in long pulse tests, the beamlet deflection is analyzed in three dimensional multibeamlet analyses. The necessary modifications shown above are applied to the MAMuG accelerator for coming long pulse tests in JAEA and ITER.

Kashiwagi, M.; Taniguchi, M.; Dairaku, M.; Grisham, L. R.; Hanada, M.; Mizuno, T.; Tobari, H.; Umeda, N.; Watanabe, K.; Sakamoto, K.; Inoue, T.

2010-02-01

420

Analyses of high power negative ion accelerators for ITER neutral beam injector (invited)  

SciTech Connect

In JAEA, research and developments to realize high power accelerator (1 MeV, 40 AD{sup -} ion beams for 3600 s) for ITER have been carried out experimentally and numerically utilizing a five stage MAMuG (Multiaperture, Multigrid) accelerator. In this paper, the extension of the gap length, which is required to improve the voltage holding capability, is examined in two dimensional beam optics analyses and also from view point of stripping loss of ions. In order to suppress excess power loadings due to the direct interception of negative ions, which is issued in long pulse tests, the beamlet deflection is analyzed in three dimensional multibeamlet analyses. The necessary modifications shown above are applied to the MAMuG accelerator for coming long pulse tests in JAEA and ITER.

Kashiwagi, M.; Taniguchi, M.; Dairaku, M.; Hanada, M.; Mizuno, T.; Tobari, H.; Umeda, N.; Watanabe, K.; Sakamoto, K.; Inoue, T. [Japan Atomic Energy Agency (JAEA), 801-1, Mukoyama, Naka 311-0193 (Japan); Grisham, L. R. [Princeton University, Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

2010-02-15

421

Simulations and Experiments of Beam-Beam Effects in e+e- Storage Rings  

SciTech Connect

Over the past decade, extensive simulations of beam-beam effects in e{sup +}e{sup -} colliders, based on the particle-in-cell method, were developed to explain many complex experimental observations. Recently, such simulations were used to predict the future luminosity performance of e{sup +}e{sup -} colliders. Some predictions have been proven to be correct in the existing accelerators. In this paper, many effects such as the beam-beam limit, crossing angle, parasitic collisions, betatron spectrum, and the beam-beam lifetime, will be directly compared between simulations and experiments.

Cai, Y.; Seeman, J.; /SLAC; Kozanecki, W.; /DAPNIA, Saclay; Ohmi, K.; Tawada, M.; /KEK, Tsukuba

2005-05-16

422

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

SciTech Connect

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

Syphers, M.J.

1987-06-01

423

Beam acceleration in the LBL 88-inch cyclotron with injection from the AECR source  

SciTech Connect

The new Advanced ECR (AECR) source is being developed for the 88-Inch Cyclotron at Lawrence Berkeley Laboratory. It operates at 14.5 GHz, compared to 6.4 GHz for the present LBL ECR source. An electron gun injects electrons into the plasma chamber to increase the production of high charge state ions. The first AECR beams were injected into the cyclotron in June of 1990 and since then a variety of ion species from the AECR have been accelerated, including beams from oxygen at 32 MeV/u to bismuth at 4.6 MeV/u. A Xe{sup 32+} beam of 1054 MeV or 8 MeV/u was accelerated. 4 refs., 3 figs., 2 tabs.

Clark, D.J.; Lyneis, C.M.; Xie, Zuqi.

1991-05-01

424

High-energy monoenergetic proton beams from two stage acceleration with a slow laser pulse  

NASA Astrophysics Data System (ADS)

We present a new regime to generate high-energy quasimonoenergetic proton beams in a "slow-pulse" regime, where the laser group velocity vgaccelerated by the light sail (LS) mode can be further trapped and reflected by the snowplough potential generated by the laser in the near-critical density plasma. These two acceleration stages are connected by the onset of Rayleigh-Taylor-like (RT) instability. The usual ion energy spectrum broadening by RT instability is controlled and high quality proton beams can be generated. It is shown by multidimensional particle-in-cell simulation that quasimonoenergetic proton beams with energy up to hundreds of MeV can be generated at laser intensities of 1 021 W /cm2 .

Wang, H. Y.; Yan, X. Q.; Zepf, M.

2015-02-01

425

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

SciTech Connect

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

Pieck, Martin [Los Alamos National Laboratory

2008-01-01

426

The 6 MV tandem accelerator project for nuclear physics and ion beam applications at the University of Tsukuba  

NASA Astrophysics Data System (ADS)

The 12UD Pelletron tandem accelerator at the University of Tsukuba suffered serious damage from the Great East Japan Earthquake on 11 March 2011. A post-quake reconstruction project has been started to construct a new middle-sized tandem accelerator instead of the broken 12UD Pelletron tandem accelerator at the 2nd target room connecting the beam line to existing facilities at the 1st target room. The new accelerator system consists of the 6 MV Pelletron tandem accelerator, new 4 ion sources, an existing Lam-shift polarized ion source and 12 beam lines. It is expected to apply for nuclear physics, accelerator mass spectrometry and ion beam applications. The construction of the new accelerator system will be completed by spring 2014.

Sasa, Kimikazu

2013-05-01

427

Results of beam tests of a prototype calorimeter for a Linear Collider  

NASA Astrophysics Data System (ADS)

The proposed International Linear Collider (ILC) requires a detector with superior jet energy resolution of 30%/?E or better near the Z-pole region (91GeV). The Calorimeter for the Linear Collider Collaboration (CALICE) is developing and testing prototype detectors with this goal in mind. One major limitation on detector resolution is the size of the hadron calorimeter contained within a magnetic coil. To compensate for "thin" calorimeters that cannot contain the highest energy particle showers, the Tail Catcher/Muon Tracker (TCMT) has been designed to include calorimetric functions and higher granularity than existing muon tracking systems. The prototype design also provided an opportunity to simulate the impact of a magnetic coil on energy resolution and to study the use of silicon photomultipliers (SiPMs) in particle detectors. This analysis shows that a TCMT six interaction lengths deep contains leakage and improves energy resolution when added to the CALICE electromagnetic and hadronic calorimeters. The effect of the TCMT both with and without a coil is more significant as energy increases. The addition of all sixteen layers of the TCMT to a 3.5 interaction length thick calorimeter improves pion resolution by 9.3% at 20 GeV and 10.8% at 80 GeV. For a 5.5 interaction length thick calorimeter system, typical of those under consideration for ILC detectors, the addition of TCMT layers after a coil of 1.8 interaction lengths improves energy resolution of 20 GeV pions by 1% and for 80 GeV pions by 2%.

Francis, Kurt

428

SLAC linear collider: the machine, the physics, and the future  

SciTech Connect

The SLAC linear collider, in which beams of electrons and positrons are accelerated simultaneously, is described. Specifications of the proposed system are given, with calculated preditions of performance. New areas of research made possible by energies in the TeV range are discussed. (GHT)

Richter, B.

1981-11-01

429

NSAC Recommends a Relativistic Heavy-Ion Collider.  

ERIC Educational Resources Information Center

Describes the plan submitted by the Nuclear Science Advisory Committee to the Department of Energy and National Science Foundation urging construction of an ultrarelativistic heavy-ion collider designed to accelerate nucleon beams of ions as heavy as uranium. Discusses the process of selecting the type of facility as well as siting. (JM)

Physics Today, 1984

1984-01-01

430

Investigation of beam transmission in A 9SDH-2 3.0 MV NEC pelletron tandem accelerator  

NASA Astrophysics Data System (ADS)

Electrostatic tandem accelerators are widely used to accelerate ions for experiments in materials science such as high energy ion implantation, materials modification, and analyses. Many applications require high beam current as well as high beam brightness at the target; thus, maximizing the beam transmission through such electrostatic accelerators becomes important. The Ion Beam Modification and Analysis Laboratory (IBMAL) at University of North Texas is equipped with four accelerators, one of which is a 9SDH-2 3.0 MV National Electrostatic Corporation (NEC) Pelletron® tandem accelerator. The tandem accelerator is equipped with three ion sources: one radio frequency-He ion source (Alphatross) and two ion sources of Cs-sputter type, the SNICS II (Source of Negative Ions by Cesium Sputtering) and a Cs-sputter source for trace-element accelerator based mass spectrometry. This work presents a detailed study of the beam transmission of hydrogen, silicon, and silver ions through the accelerator using the SNICS ion source with injection energies ranging from 20 keV to 70 keV. The beam transmission is quantified for three different terminal voltages: 1.5 MV, 2.0 MV and 2.5 MV. For a given terminal voltage, it has been found that beam transmission is strongly dependent on the ion source injector potential. Details of experiments and data analysis are presented.

Deoli, Naresh T.; Kummari, Venkata C.; Pacheco, Jose L.; Duggan, Jerome L.; Glass, Gary A.; McDaniel, Floyd D.; Reinert, Tilo; Rout, Bibhudutta; Weathers, Duncan L.

2013-04-01

431

Accelerated Nuclear Energy Materials Development with Multiple Ion Beams  

SciTech Connect

A fundamental issue in nuclear energy is the changes in material properties as a consequence of time, temperature, and neutron fluence. Usually, candidate materials for nuclear energy applications are tested in nuclear reactors to understand and model the changes that arise from a combination of atomic displacements, helium and hydrogen production, and other nuclear transmutations (e.g. fission and the production of fission products). Experiments may be carried out under neutron irradiation conditions in existing nuclear materials test reactors (at rates of 10 to 20 displacements per atom (DPA) per year or burn-up rates of a few percent per year for fertile fuels), but such an approach takes much too long for many high neutron fluence scenarios (300 DPA for example) expected in reactors of the next generation. Indeed it is reasonable to say that there are no neutron sources available today to accomplish sufficiently rapid accelerated aging let alone also provide the temperature and spectral characteristics of future fast spectrum nuclear energy systems (fusion and fission both). Consequently, materials research and development progress continues to be severely limited by this bottleneck.

Fluss, M J; Bench, G

2009-08-19

432

Hadron production measurements to constrain accelerator neutrino beams  

E-print Network

A precise prediction of expected neutrino fluxes is required for a long-baseline accelerator neutrino experiment. The flux is used to measure neutrino cross sections at the near detector, while at the far detector it provides an estimate of the expected signal for the study of neutrino oscillations. In the talk several approaches to constrain the neutrino flux are presented. The first is the traditional one when an interaction chain for the neutrino parent hadrons is stored to be weighted later with real measurements. In this approach differential hadron cross sections are used which, in turn, are measured in ancillary hadron production experiments. The approach is certainly model dependent because it requires an extrapolation to different incident nucleon momenta assuming x_F scaling as well as extrapolation between materials having different atomic numbers. In the second approach one uses a hadron production yields off a real target exploited in the neutrino beamline. Yields of neutrino parent hadrons are parametrized at the surface of the target, thus one avoids to trace the particle interaction history inside the target. As in the case of the first approach, a dedicated ancillary experiment is mandatory. Recent results from the hadron production experiments - NA61/SHINE at CERN (measurements for T2K) and MIPP at Fermilab (measurements for NuMI) - are reviewed.

Alexander Korzenev

2014-09-28

433

Reconstruction of Initial Beam Conditions at the Exit of the DARHT II Accelerator  

E-print Network

We consider a technique to determine the initial beam conditions of the DARHT II Accelerator by measuring the beam size under three different magnetic transport settings. This may be time gated to resolve the parameters as a function of time within the 2000 nsec pulse. This technique leads to three equations in three unknowns with solution giving the accelerator exit beam radius, tilt and emittance. We find that systematic errors cancel and so are not a problem in unfolding the initial beam conditions. Random uncorrelated shot to shot errors can be managed by one of three strategies: 1) make the transport system optically de-magnifying; 2) average over many individual shots; or 3) make the random uncorrelated shot to shot errors sufficiently small. The high power of the DARHT II beam requires that the beam transport system leading to a radius measuring apparatus be optically magnifying. This means that the shot to shot random errors must either be made small (less than about 1%) or that we average each of the...

Paul, A C

2000-01-01

434

Ion acceleration and abundance enhancements by electron beam instabilities in impulsive solar flares  

NASA Technical Reports Server (NTRS)

We show that a nonrelativistic electron beam in a hydrogen-helium solar flare plasma will excite H(+) electromagnetic ion cyclotron, shear Alfven, and R-X waves, in addition to waves resulting from the two-stream instability. The H(+) electromagnetic ion cyclotron and shear Alfven waves are able to selectively accelerate ambient He-3 and Fe, respectively, to MeV energies through first harmonic gyroresonance, and thereby account for the large (He-3)/(He-4) and Fe/C ratios seen in the energetic particles from impulsive solar flares. In this model, separate heating and acceleration mechanisms for either He-3 or Fe are not required, and Fe acceleration is quite efficient since it does not need to occur by second harmonic gyroresonance. The combination of the other two unstable modes is able to accelerate ions to hundreds of MeV if the particles become trapped in an electrostatic potential well of a two-stream wave.

Miller, James A.; Vinas, Adolfo F.

1993-01-01

435

Booster-Nuclotron beam line for NICA project  

NASA Astrophysics Data System (ADS)

This paper presents the concept of the booster-Nuclotron beam line for the Nuclotron-based Ion Collider fAcility (NICA) accelerator complex being developed at the Joint Institute for Nuclear Research (Dubna, Russia). The beam line serves for ion beam transportation and stripping at an intermediate energy. The magnetic system of the beam line is considered. The results of a simulation of gold Au32+/Au79+ ion beam dynamics in the beam line are presented.

Tuzikov, A. V.; Mikhailov, V. A.

2010-12-01

436

Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab  

SciTech Connect

A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.

Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S.; Rakhno, I.; /Fermilab

2012-05-10

437

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

SciTech Connect

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

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

2010-10-15

438

Quasimonoenergetic collimated electron beams from a laser wakefield acceleration in low density pure nitrogen  

SciTech Connect

A laser wakefield acceleration (LWFA) experiment is performed using 30 TW, 30 fs, and 800?nm laser pulses, focused onto pure nitrogen plasma having relatively low densities in the range of 0.8×10{sup 18}?cm{sup ?3} to 2.7×10{sup 18}?cm{sup ?3}. Electron beams having a low divergence of ?3??mrad (full-width at half-maximum) and quasi-monoenergetic peak energies of ?105??MeV are achieved over 4-mm interaction length. The total electron beam charge reached to 2 nC, however, only 1%–2% of this (tens of pC) had energies >35?MeV. We tried different conditions to optimize the electron beam acceleration; our experiment verifies that lower nitrogen plasma densities are generating electron beams with high quality in terms of divergence, charge, pointing stability, and maximum energy. In addition, if LWFA is to be widely used as a basis for compact particle accelerators in the future, therefore, from the economic and safety points of view we propose the use of nitrogen gas rather than helium or hydrogen.

Tao, Mengze [Key Laboratory for Laser Plasmas (MOE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Bejing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Hafz, Nasr A. M., E-mail: nasr@sjtu.edu.cn; Li, Song; Mirzaie, Mohammad; Elsied, Ahmed M. M.; Ge, Xulei; Liu, Feng; Sokollik, Thomas; Sheng, Zhengming; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (MOE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Chen, Liming [Bejing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-07-15

439

Electron beam accelerator: A new tool for environmental preservation in Malaysia  

NASA Astrophysics Data System (ADS)

Electron beam accelerators are widely used for industrial applications such as surface curing, crosslinking of wires and cables and sterilization/ decontamination of pharmaceutical products. The energy of the electron beam determines the type of applications. This is due to the penetration power of the electron that is limited by the energy. In the last decade, more work has been carried out to utilize the energetic electron for remediation of environmental pollution. For this purposes, 1 MeV electron beam accelerator is sufficient to treat wastewater from textile industry and flue gases from fossil fuel combustions. In Nuclear Malaysia, a variable energy Cockroft Walton type accelerator has been utilized to initiate investigations in these two areas. An electron beam flue gas treatment test rig was built to treat emission from diesel combustion, where it was found that using EB parameters of 1MeV and 12mA can successfully remove at least 80% of nitric oxide in the emission. Wastewater from textile industries was treated using combination of biological treatment and EB. The initial findings indicated that the quality of water had improved based on the CODCr, BOD5 indicators.

Hashim, Siti Aiasah; Bakar, Khomsaton Abu; Othman, Mohd Nahar

2012-09-01

440

Quasimonoenergetic collimated electron beams from a laser wakefield acceleration in low density pure nitrogen  

NASA Astrophysics Data System (ADS)

A laser wakefield acceleration (LWFA) experiment is performed using 30 TW, 30 fs, and 800 nm laser pulses, focused onto pure nitrogen plasma having relatively low densities in the range of 0.8 × 10 18 cm - 3 to 2.7 × 10 18 cm - 3. Electron beams having a low divergence of ˜ 3 mrad (full-width at half-maximum) and quasi-monoenergetic peak energies of ˜ 105 MeV are achieved over 4-mm interaction length. The total electron beam charge reached to 2 nC, however, only 1%-2% of this (tens of pC) had energies >35 MeV. We tried different conditions to optimize the electron beam acceleration; our experiment verifies that lower nitrogen plasma densities are generating electron beams with high quality in terms of divergence, charge, pointing stability, and maximum energy. In addition, if LWFA is to be widely used as a basis for compact particle accelerators in the future, therefore, from the economic and safety points of view we propose the use of nitrogen gas rather than helium or hydrogen.

Tao, Mengze; Hafz, Nasr A. M.; Li, Song; Mirzaie, Mohammad; Elsied, Ahmed M. M.; Ge, Xulei; Liu, Feng; Sokollik, Thomas; Chen, Liming; Sheng, Zhengming; Zhang, Jie

2014-07-01