Keyword: plasma
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SUPB011 Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression Below the Shot-noise Limit electron, linac, simulation, beam-transport 25
 
  • A. Nause, A. Gover
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
 
  Funding: We acknowledge support of the Israel Science Foundation grant
We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation [1]. Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian.
[1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009
[2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955)
[3] P. Emma, et al , Nature Photonics 4, 641 (2010)
[4] A. Dicke, Phys. Rev. 93, 99 (1954)
 
 
MOPB087 S-Band Loads for SLAC Linac linac, klystron, vacuum, insertion 378
 
  • A. Krasnykh, F.-J. Decker
    SLAC, Menlo Park, California, USA
  • R.W. LeClair
    INTA, Santa Clara, USA
 
  Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515 and SBIR grant number DE-SC0007661
The S-Band loads on the current SLAC linac RF system were designed, in some cases, 40+ years ago to terminate 2-3 MW peak power into a thin layer of coated Kanthal material as the high power absorber [1]. The technology of the load design was based on a flame-sprayed Kanthal wire method onto a base material. During SLAC linac upgrades, the 24 MW peak klystrons were replaced by 5045 klystrons with 65+ MW peak output power. Additionally, SLED cavities were introduced and as a result, the peak power in the current RF setup has increased up to 240 MW peak. The problem of reliable RF peak power termination and RF load lifetime required a careful study and adequate solution. Results of our studies and three designs of S-Band RF load for the present SLAC RF linac system is discussed. These designs are based on the use of low conductivity materials.
[1] “The Stanford Two-Mile Accelerator”, p. 376-381, R. B. Neal, General Editor, 1968, W. A. Benjamin, Inc., NY Amsterdam
 
 
TUPLB05 Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression below the Shot-Noise Limit electron, linac, simulation, beam-transport 451
 
  • A. Gover
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
  • A. Nause
    University of Tel Aviv, Tel Aviv, Israel
 
  Funding: We acknowledge support of the Israel Science Foundation grant
We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation [1]. Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian.
[1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009
[2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955)
[3] P. Emma, et al , Nature Photonics 4, 641 (2010)
[4] A. Dicke, Phys. Rev. 93, 99 (1954)
 
 
TUPB005 Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression Below the Shot-noise Limit electron, linac, simulation, beam-transport 482
 
  • A. Gover
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
  • A. Nause
    University of Tel Aviv, Tel Aviv, Israel
 
  Funding: We acknowledge support of the Israel Science Foundation grant
We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation.[1] Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian.
[1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009
[2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955)
[3] P. Emma, et al , Nature Photonics 4, 641 (2010)
[4] A. Dicke, Phys. Rev. 93, 99 (1954)
 
 
TUPB021 Study of Plasma Effect in Longitudinal Space Charge Induced Microbunching Instability electron, impedance, linac, space-charge 522
 
  • D. Huang, Q. Gu
    SINAP, Shanghai, People's Republic of China
  • K.Y. Ng
    Fermilab, Batavia, USA
 
  The longitudinal space charge (LSC) plays an important role in introducing the microbunching instability in the LINAC of a free electron laser (FEL) facility. The current model of LSC impedance [1] derived from the fundamental electromagnetic theory [2] is widely used to explain the growth of the microbunching instability [3]. However, in the case of highly bright relativistic electron beams, the plasma effect starts to play a role. In this article, the basic model of LSC impedance including the plasma effect is built , and the modifications to the microbunching instability based on the new model are discussed in various conditions.
[1] Marco Venturini, Phys Rev. ST Accel. Beams 11, 034401 (2008)
[2] J. D. Jackson, Classical Electrodynamics (Wiley, 1999)
[3] Z. Huang, et. al., Phys, Rev. ST Accel. Beams 7, 074401 (2004)
 
 
TH2A004 Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression Below the Shot-noise Limit electron, linac, simulation, beam-transport 783
 
  • A. Gover
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
  • A. Nause
    University of Tel Aviv, Tel Aviv, Israel
 
  Funding: We acknowledge support of the Israel Science Foundation grant
We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation.[1] Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian.
[1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009
[2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955)
[3] P. Emma, et al , Nature Photonics 4, 641 (2010)
[4] A. Dicke, Phys. Rev. 93, 99 (1954)
 
 
TH3A04 Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET electron, radiation, linac, acceleration 802
 
  • C.I. Clarke, E. Adli, S. Corde, F.-J. Decker, R.J. England, R.A. Erickson, A.S. Fisher, S.J. Gessner, C. Hast, M.J. Hogan, S.Z. Li, N. Lipkowitz, M.D. Litos, Y. Nosochkov, J.T. Seeman, J. Sheppard, I. Tudosa, G.R. White, U. Wienands, M. Woodley, Z. Wu, G. Yocky
    SLAC, Menlo Park, California, USA
  • C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, N. Vafaei
    UCLA, Los Angeles, California, USA
 
  Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 um) bunches and small (20 um wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of THz radiation for material studies. We present the FACET design, initial operating experience and first science from the facility.
 
slides icon Slides TH3A04 [3.091 MB]  
 
THPB037 Iron Beam Acceleration with DPIS rfq, injection, ion, laser 936
 
  • M. Okamura
    BNL, Upton, Long Island, New York, USA
  • P.J. Jandovitz
    Cornell University, Ithaca, New York, USA
  • T. Kanesue
    IAP, Frankfurt am Main, Germany
  • M. Sekine
    RLNR, Tokyo, Japan
  • T. Yamamoto
    RISE, Tokyo, Japan
 
  Funding: The work supported by US. DOE and RIKEN Japan.
It has been proved that direct plasma Injection Scheme (DPIS) is an efficient way to accelerate high current highly charged state heavy ion beam. More than 50 mA (peak current) of various heavy ion beams can be easily accelerated. However, it was rather difficult to obtain longer pulse especially for highly charged particles. To induce highly charged states ions, a high plasma temperature is required at the laser irradiation point and the high temperature automatically gives a very fast expansion velocity of the plasma. This shortens the ion beam pulse length. To compensate the shorter ion pulse length, we can extend the plasma drift length, but it will dilute the brightness of the plasma since the plasma expands three dimensionally. To avoid the reduction of the brightness, a simple long solenoid was applied to confine the diverging angle of the plasma expansion. In the conference, this new technique will be explained and the latest results of iron beam acceleration will be shown.
 
 
THPB076 Design Issues of the Proton Source for the ESS Facility proton, emittance, ion, extraction 1008
 
  • L. Celona, L. Allegra, C. Caliri, G. Castro, G. Ciavola, R. Di Giugno, S. Gammino, D. Mascali, L. Neri
    INFN/LNS, Catania, Italy
 
  The European Spallation Source facility will be one of the fundamental instruments for science and engineering of the future. A 2.5 GeV proton accelerator is to be built for the neutron production. INFN-LNS is involved in the Design Update for the proton source and Low Energy Beam Transport (LEBT) line. The proton source is required to produce a low emittance 90 mA beam, 2.86 ms pulsed with a repetition rate of 14 Hz. Microwave Discharge Ion Sources (MDIS) enable us to produce such high intensity proton beams characterized by very low emittance (< 0.2 π.mm.mrad). The source design is based on a flexible magnetic system which can be adapted to electrostatic Bernstein waves heating mechanism; this will permit a strong increase in the electron density with an expected boost of the output current. The main features of the source design, including the microwave injection system and beam extraction, will be described hereinafter.  
 
FR1A01 Heavy Ion Strippers ion, heavy-ion, electron, cyclotron 1050
 
  • F. Marti
    FRIB, East Lansing, Michigan, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Stripping of high current heavy ion beams is a key technology for future accelerator as FAIR (Germany) and FRIB (USA) and current ones as RIBF (RIKEN, Japan). A small change in the peak charge state produced at the stripper could require a significant expense in additional accelerating stages to obtain the required final energy. The main challenges are the thermal effects due to the high power deposition (~ 50 kW/mm3) and the radiation damage due to the high energy deposition. The effects of heavy ion beams are quite different from proton beams because of the much shorter range in matter. We will present an overview talk considering charge stripping devices like carbon foils and gas cells used worldwide as well as the current research efforts on plasma stripping, liquid metal strippers, etc. The advantages and disadvantages of the different options will be presented.
 
slides icon Slides FR1A01 [4.174 MB]  
 
FR1A02 Light Ion ECR Sources State of the Art for Linacs ion, ion-source, emittance, extraction 1055
 
  • R. Gobin
    CEA/IRFU, Gif-sur-Yvette, France
  • N. Chauvin, O. Delferrière, O. Tuske, D. Uriot
    CEA/DSM/IRFU, France
 
  Since the middle of the 90’s development of high intensity light ion injectors are undertaken at CEA-Saclay. The first 100 mA proton beam has been produced by the SILHI ECR source in the framework of the IPHI project. Ever since, more than 100 mA of protons or deuteron beams, with high purities, have been regularly produced in pulsed or continuous mode, and with very good beam characteristics analyzed in dedicated beam diagnostics. CEA-Saclay is currently involved in several high intensity LINAC projects such as Spiral2, IFMIF-EVEDA and FAIR, and is in charge of their source and LEBT design and construction. This article reports the latest developments and experimental results carried out at CEA-Saclay for the 3 projects. In addition, a review of the developments and beam results performed in other laboratories worldwide will be also presented.  
slides icon Slides FR1A02 [4.743 MB]