04 Extreme Beams, Sources and Other Technologies
4H Other Extreme
Paper Title Page
MO3A04 Accelerator/Decelerator of Slow Neutrons 133
 
  • M. Kitaguchi
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • Y. Arimoto, H.M. Shimizu
    KEK, Ibaraki, Japan
  • P.W. Geltenbort
    ILL, Grenoble, France
  • S. Imajo
    Kyoto University, Kyoto, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • Y. Seki
    RIKEN Nishina Center, Wako, Japan
  • T. Yoshioka
    Kyushu University, Fukuoka, Japan
 
  Funding: Supported by the Quantum Beam Fundamentals Development Program MEXT, a Grant-in-Aid for Creative Scientific Research of MEXT Program No.19GS0210 and No.23244047, Yamada Science Foundation, and KEK.
An accelerator/decelerator for slow neutron beams has been demonstrated. The energy of a neutron can be increased or decreased by flipping the neutron spin (directly coupled to magnetic dipole moment) in magnetic field. This device is a combination of a gradient magnetic field and an RF magnetic field. Because the RF frequency for the spin flip is a function of the external magnetic field, only neutrons that are located in a specific magnetic field level will be spin-flipped at a given RF frequency. By changing the RF frequency, the energy change can be selected in the gradient magnetic field. The maximum field of the gradient magnet is 1 T, which corresponds to the energy change of 120 neV. The magnetic field linearly decreases to 0.2T within 25 cm. By putting this device on a beamline from a pulsed neutron source, neutron rebuncher is realized. The dense slow neutrons are important to suppress the systematic errors for the measurement of neutron electric dipole moment (nEDM). The combination of spallation neutron source and this neutron rebuncher is suitable to the measurement of nEDM. A review of current status of our plan for nEDM experiment at J-PARC will be also presented.
 
slides icon Slides MO3A04 [3.750 MB]  
 
MOPLB11 The Upgraded Argonne Wakefield Accelerator Facility (AWA): a Test-Bed for the Development of High Gradient Accelerating Structures and Wakefield Measurements 168
 
  • M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
    ANL, Argonne, USA
  • S.P. Antipov, C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • E.E. Wisniewski
    Illinois Institute of Technology, Chicago, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
Electron beam driven wakefield acceleration is a bona fide path to reach high gradient acceleration of electrons and positrons. With the goal of demonstrating the feasibility of this concept with realistic parameters, well beyond a proof-of-principle scenario, the AWA Facility is currently undergoing a major upgrade that will enable it to achieve accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure. A key aspect of the studies and experiments carried out at the AWA facility is the use of relatively short RF pulses (15 – 25 ns), which is believed to mitigate the risk of breakdown and structure damage. The upgraded facility will utilize long trains of high charge electron bunches to drive wakefields in the microwave range of frequencies (8 to 26 GHz), generating RF pulses with GW power levels.
 
slides icon Slides MOPLB11 [0.900 MB]  
 
MOPLB12 X-Ray Local Energy Spectrum Measurement on Tsinghua Thomson Scattering X-Ray Source (TTX) 171
 
  • Y.-C. Du, J.F. Hua, W.-H. Huang, C.-X. Tang, L.X. Yan, H. Zha, Z. Zhang
    TUB, Beijing, People's Republic of China
 
  Thomson scattering X-ray source, in which the TW laser pulse is scattered by the relativistic electron beam, can provide ultra short, monochromatic, high flux, tunable polarized hard X-ray pulse which is can widely used in physical, chemical and biological process research, ultra-fast phase contrast imaging, and so on. Since the pulse duration of X-ray is as short as picosecond and the flux in one pulse is high, it is difficult to measure the x-ray spectrum. In this paper, we present the X-ray spectrum measurement experiment on Tsinghua Thomson scattering. The preliminary experimental results shows the maximum X-ray energy is about 47 keV, which is agree well with the simulations.  
slides icon Slides MOPLB12 [1.311 MB]  
 
MOPB089 X-Ray Local Energy Spectrum Measurement at Tsinghua Thomson Scattering X-Ray Source (TTX) 383
 
  • Y.-C. Du, J.F. Hua, W.-H. Huang, C.-X. Tang, L.X. Yan, H. Zha, Z. Zhang
    TUB, Beijing, People's Republic of China
 
  Thomson scattering X-ray source, in which the TW laser pulse is scattered by the relativistic electron beam, can provide ultra short, monochromatic, high flux, tunable polarized hard X-ray pulse which is can widely used in physical, chemical and biological process research, ultra-fast phase contrast imaging, and so on. Since the pulse duration of X-ray is as short as picosecond and the flux in one pulse is high, it is difficult to measure the x-ray spectrum. In this paper, we present the X-ray spectrum measurement experiment on Tsinghua Thomson scattering. The preliminary experimental results shows the maximum X-ray energy is about 47 keV, which is agree well with the simulations.  
 
MOPB093 The Upgraded Argonne Wakefield Accelerator Facility (AWA): a Test-Bed for the Development of High Gradient Accelerating Structures and Wakefield Measurements 392
 
  • M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
    ANL, Argonne, USA
  • S.P. Antipov, C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • E.E. Wisniewski
    Illinois Institute of Technology, Chicago, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
Electron beam driven wakefield acceleration is a bona fide path to reach high gradient acceleration of electrons and positrons. With the goal of demonstrating the feasibility of this concept with realistic parameters, well beyond a proof-of-principle scenario, the AWA Facility is currently undergoing a major upgrade that will enable it to achieve accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure. A key aspect of the studies and experiments carried out at the AWA facility is the use of relatively short RF pulses (15 – 25 ns), which is believed to mitigate the risk of breakdown and structure damage. The upgraded facility will utilize long trains of high charge electron bunches to drive wakefields in the microwave range of frequencies (8 to 26 GHz), generating RF pulses with GW power levels.
 
 
THPB095 Designing of a Phase-mask-type Laser Driven Dielectric Accelerator for Radiobiology 1041
 
  • K. Koyama
    UTNL, Ibaraki, Japan
  • A. Aimidura, M. Uesaka
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
  • Y. Matsumura
    University of Tokyo, Tokyo, Japan
  • T. Natsui, M. Yoshida
    KEK, Ibaraki, Japan
 
  Funding: This work is supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120
In order to estimate the health risk of a low radiation dose, basic processes of the radiobiology should be clarified by shooting a DNA using a spatially and temporary defined particle beam or X-ray. A suitable beam size is as small as a resolving power of an optical microscope of a few hundred nanometers. Photonic crystal accelerators (PCA) are capable of delivering nm-beams of sub-fs pulses because the characteristic length and frequency of PCAs are on the order of the laser light. Since the phase-mask type accelerator has a simpler structure than other types of PCAs, we are designing a phase-mask type laser driven dielectric accelerator. By adopting an unbalanced length of pillar and ditch (grating) of 4:1, a standing wave like acceleration field is produced in a acceleration channel. A pillar height and initial speed of injected electron are determined by analytically. The maximum acceleration gradient of 2 GeV/m is estimated. The required laser power is roughly estimated to be 6.5 GW. The simulation using CST-code also shows similar values to accelerate electrons by the phase-mask type accelerator.
 
 
THPB096 High-power Sources of RF Radiation Driven by Periodic Laser Pulses 1044
 
  • S.V. Kuzikov, A.V. Savilov
    IAP/RAS, Nizhny Novgorod, Russia
  • S.V. Kuzikov
    Omega-P, Inc., New Haven, USA
 
  Funding: Supported in part by DoE USA.
A fast, periodic modulation of electron RF sources can be carried out in a form of Q-factor switching by means of fast RF switches, or in a form of I-switching by means of the bunched electron beam. If modulation frequency equals to time which is necessary for RF radiation to travel along the cavity and to come back, the RF oscillator can produce periodic, giant, short pulses which are desirable for many applications in order to avoid a breakdown. The produced RF pulses are phase and frequency locked by modulation shape. The mentioned effects of the phase and frequency locking remain also possible for RF sources operated in a single-mode regime. In last case the modulation frequency should be close to natural single-mode oscillation frequency. For example, one might control operation of a BWO by means of a small periodical modulation of the electron voltage in a drift section in-between a cathode and the corrugated interaction section. The necessary voltage modulation can be provided by means of a DC generator those voltage due to a photoconductivity is externally modulated with definite frequency by laser which irradiates GaAs isolator inserted in-between the electrodes.
 
 
FR1A01 Heavy Ion Strippers 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]  
 
FR2A02
Antihydrogen Trapping and Probing at the Alpha-CERN Experiment  
 
  • E. Sarid
    NRCN, Beer-Sheva, Israel
  • A.C. Collaboration
    CERN, Geneva, Switzerland
 
  Precision spectroscopic comparison of hydrogen and antihydrogen (AH) holds the promise of sensitive tests of the Charge/Parity/Time (CPT) theorem and matter-antimatter equivalence. The clearest path towards realizing this goal is to hold a sample of AH atoms in an atomic trap for interrogation by electromagnetic radiation. At the ALPHA experiment in CERN, AH atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of eV, more than 104 times the maximum trappable kinetic energy. During the last two years ALPHA demonstrated the first trapping of AH atoms (*November 2010), the ability to hold the trapped AH atoms for 1000s (**June 2011), and the first resonant microwave interactions probing the hyperfine structure of the AH ground state (***March 2012). With microwave resonant radiation we succeeded making positron spin flips, making trapped atoms un-trappable. An upgraded version of the ALPHA experiment will allow us to progress towards microwave and laser precision spectroscopy of the trapped antihydrogen atoms.
* G.B.Andresen et al, ALPHA collaboration, Nature 468,673(2010)
** G.B.Andresen et al, ALPHA collaboration, Nature Physics,7,558(2011)
*** C. Amole, ALPHA collaboration, Nature 483, 439 (2012)