03 Linear Colliders, Lepton Accelerators and New Acceleration Techniques

A14 Advanced Concepts

Paper Title Page
THPD046 Initial Results on Electron Beam Generation using Pyroelectric Crystals 4384
 
  • U.H. Lacroix, D.M. Fong, G. Travish, N. Vartanian
    UCLA, Los Angeles
  • E.R. Arab
    PBPL, Los Angeles
  • R.B. Yoder
    Manhattanville College, Purchase, New York
 
 

Pyroelectric crystals, which produce large surface electric fields during heating and cooling, have been proposed as a mechanism for constructing a stand-alone electron beam source. We report on experimental tests of this concept, using a variety of field emission tips combined with a pyroelectric crystal to produce a low-energy electron beam during thermal cycling. The mechanism is suitable for generating very small electron bunches, with energies up to tens of kilovolts, for use in microaccelerator structures.

 
THPD050 A Proposed Experiment on the Proton Driven Plasma Wakefield Acceleration 4392
 
  • A. Caldwell, G.X. Xia
    MPI-P, München
  • R.W. Assmann, F. Zimmermann
    CERN, Geneva
  • K.V. Lotov
    BINP SB RAS, Novosibirsk
  • A.M. Pukhov
    HHUD, Dusseldorf
 
 

Proton driven plasma wakefield acceleration holds promise to accelerate a bunch of electrons to the energy frontier in a single acceleration channel. To verify this novel idea, a demonstration experiment is now being planned. The idea is to use the high energy proton bunches from the Super Proton Synchrotron (SPS) at CERN, to shoot them into a plasma cell and drive large amplitude of plasma wake. The interactions between the plasma and protons are simulated and the results are presented in this paper.

 
THPD051 Producing Short Proton Bunch for Driving Plasma Wakefield Acceleration 4395
 
  • G.X. Xia, A. Caldwell
    MPI-P, München
 
 

A high energy, intense and short proton bunch can be employed to excite an interesting plasma wakefield for the electron beam acceleration. To excite a large amplitude of plasma wave, a short driver is thus required. In this paper, several proton bunch compression scenarios are analyzed. A magnetic bunch compressor is designed to compress the SPS proton beam for the demonstration experiment at CERN. The simulation results of bunch compression are given.

 
THPD052 Manipulation of Negatively Charged Beams via Coherent Effects in Bent Crystals 4398
 
  • V. Guidi, E. Bagli, A. Mazzolari
    INFN-Ferrara, Ferrara
  • A.G. Afonin, Y.A. Chesnokov, V.A. Maisheev, I.A. Yazynin
    IHEP Protvino, Protvino, Moscow Region
  • S. Baricordi, P. Dalpiaz, M. Fiorini, D. Vincenzi
    UNIFE, Ferrara
  • D. Bolognini, S. Hasan, M. Prest
    Università dell'Insubria & INFN Milano Bicocca, Como
  • G. Della Mea, R. Milan
    INFN/LNL, Legnaro (PD)
  • A.S. Denisov, Yu.A. Gavrikov, Yu.M. Ivanov, L.P. Lapina, L.G. Malyarenko, V. Skorobogatov, V.M. Suvorov, S.A. Vavilov
    PNPI, Gatchina, Leningrad District
  • S. Golovatyuk, A.D. Kovalenko, A.M. Taratin
    JINR, Dubna, Moscow Region
  • A. Mattera
    INFN MIB, MILANO
  • W. Scandale
    CERN, Geneva
  • S. Shiraishi
    Enrico Fermi Institute, University of Chicago, Chicago, Illinois
  • E. Vallazza
    INFN-Trieste, Trieste
  • A. V. Vomiero
    INFM-CNR, Istituto Nazionale di Fisica della Materia - Consiglio Nazionale delle Ricerche, Brescia
 
 

New results in coherent interaction of negatively-charged particles with bent crystals showed unprecedentedly and significantly high efficiency to manipulate such beams, in the same way as for positively charged particles. Key feature under experimental attainment was the usage of high-quality suitably thin silicon crystals. We experimentally tested crystals Vs. 150 GeV negative pions at external lines of CERN SPS. We observed planar channeling at full deflection angle 30% high single-pass efficiency and large acceptance (about 20μrad). Moreover in the axial case, we reached more than 90% deflection efficiency and larger acceptance (about 60μrad). We also observed volume reflection in a bent crystal, at more than 70% single-pass efficiency with such a wide acceptance as the bending angle. At last, volume reflection by several planes in a single bent crystal was successfully tested with very high efficiency (about 80%). In summary both channeling and volume reflection modes appear to be useful technique for the manipulation of negatively charged beams, e.g. for collimation in the new generation of high intensity accelerators.


The UA9 collaboration

 
THPD053 Capture and Transport of Electron Beams from Plasma Injectors 4401
 
  • P. Antici, A. Mostacci
    INFN/LNF, Frascati (Roma)
  • C. Benedetti
    Bologna University, Bologna
  • M. Migliorati, L. Palumbo
    Rome University La Sapienza, Roma
 
 

Electron beams produced by laser-plasma interaction are attracting the interest of the conventional accelerator community. In particular Laser-accelerated electrons are particularly interesting as source, considering their high initial energy and their strong beam current. Moreover, the advantages of using laser-plasma electron beam can be expressed in terms of size and cost of the global accelerating infrastructure. However, improvements are still necessary since, currently, the many laser-accelerated beams are characterized by a large energy spread and a high beam divergence that degrades quickly the electron beam properties and makes those sources not suitable as a replacement of conventional accelerators. In this paper, we report on the progress of the study related to capture, shape and transport of laser generated electrons by means of tracking codes. Our study has focused on laser-generated electrons obtained nowadays by conventional multi hundred TW laser systems and on numerical predictions. We analyze different lattice structures, working on the optimization of the capture and transport of laser-accelerated electrons. Results and open problems are shown and discussed.

 
THPD054 Inverse Compton Scattering by Laser Accelerated Electrons and its Application to Standoff Detection of Hidden Objects 4404
 
  • Y. Kitagawa, K. Fujita, R. Hanayama, K. Ishii, Y. Mori
    GPI, Hamamatsu
  • T. Kawashima
    Hamamatsu Photonics K.K., Hamamatsu
  • H. Kuwabara
    IHI, Yokohama
 
 

A technique for remote detection of hidden objects is an urgent issue, but is not yet realized, because a source and a sensor must be located on the same side of the object. An ultra-intense laser can produce extremely short and directional radiations, that is the inverse Compton scatterings used for the backscattering system. We here demonstrate that the laser-wakefiled-accelerated 10-MeV electrons inversely scatter the same laser light to keV X-ray emissions. A 10 TW OPCPA Ti:sapphire laser BEAT ( 1J output, wavelength 815 nm, and pulse width 150fs) is divided to two beams. A 0. 8-J beam is focused to an entrance edge of helium gasjet to accelerate electrons via wakefield and the other 0.2-J beam is focused to the exit of the plasma channel from the opposite direction. A second harmonic probe light measured the channel density. To the upstream direction of the latter beam, a CdTe detector analyzed the Compton spectrum under a photon counting mode* in the range of 1 keV to 20 keV, which well agrees with that calculated from the obtained electron spectrum up to a few tens MeV. We also have observed that the emission is strong into the laser axis direction.


*H. Kuwabara, Y. Mori, Y. Kitagawa, 'Coincident Measurement of a Weakly Backscattered X-ray with a CPA Laser-Produced X-ray Pulse', Plasma Fusion Research: 3, 003-004 (2008).

 
THPD055 Improvement in Proton Beam Properties during Laser Acceleration and Propagation 4407
 
  • Y.Y. Ma, S. Kawata, K. Takahashi
    Center for Optical Research and Education, Utsunomiya University, Utsunomiya
  • Y.Q. Gu, Y.Y. Ma
    Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang
  • F.Q. Shao
    National University of Defense Technology, Graduate School, Changsha
  • Z.M. Sheng
    Shanghai Jiao Tong University, Shanghai
  • Y. Yin, T.P. Yu, D. F. Zhou
    National University of Defense Technology, Changsha, Hunan
  • M.Y. Yu
    Ruhr-Universität Bochum, Bochum
  • H.B. Zhuo
    National University of Defense Technology, Parallel and Distributed Processing, Changsha
 
 

Energetic protons of tens MeV or more produced by intense lasers have been observed in recent experiments and numerical simulations. Meanwhile, significant efforts have been made to improve the proton beam quality *,**,***. For most applications, it is important to improve the quality of the proton beam both during the production and during the propagation. Some schemes are proposed to improve the quality of the proton beam both during the production form the laser plasma interaction and during the propagation. The physics is investigated by 2D3V and 3D particle-in-cell codes PLASIM and PLASIM3D. In this paper, we propose to use an umbrella-like target to accelerate, and collimate protons. It is found that high intensity collimated MeV-proton beams can be produced ****. We also propose a scheme to generate quasi-monoenergetic proton beam from the interactions of an ultra-intense laser pulse and a thin tailored hole target. Particle simulation shows that a monoenergetic proton beam is generated from the hole. The propagation of a proton beam both in vacuum and in a plasma is also studied. Compared with the propagation in vacuum, the proton beam quality can be improved obviously.


* T. Toncian, et al. Science 312, 410(2006).
** B. M. Hegelich, et al. Nature 439, 441(2006).
*** H. Schwoerer, et al. Nature 439, 445(2006).
**** Y. Y. Ma et al., Phys Plasmas 16, 34502(2009).

 
THPD056 Experimental Program for the CLIC Test Facility 3 Test Beam Line 4410
 
  • E. Adli
    University of Oslo, Oslo
  • A.E. Dabrowski, S. Döbert, M. Olvegård, D. Schulte, I. Syratchev
    CERN, Geneva
  • R.L. Lillestol
    NTNU, Trondheim
 
 

The CLIC Test Facility 3 Test Beam Line is the first prototype for the CLIC drive beam decelerator. Stable transport of the drive beam under deceleration is a mandatory component in the CLIC two-beam scheme. In the Test Beam Line more than 50% of the total energy will be extracted from a 150 MeV, 28 A electron drive beam, by the use of 16 Power Extraction and Transfer structures. A number of experiments are foreseen to investigate the drive beam characteristics under deceleration in the Test Beam Line, including beam stability, beam blow up and the efficiency of the power extraction. General benchmarking of decelerator simulation and theory studies will also be performed. Specially designed instrumentation including precision BPMs, loss monitors and a time-resolved spectrometer dump will be used for the experiments. This paper describes the experimental program foreseen for the Test Beam Line, including the relevance of the results for the CLIC decelerator studies.

 
THPD057 The Analysis of Tunable Dielectric Loaded Wakefield Accelerating Structure of Rectangular Geometry 4413
 
  • I.L. Sheynman, A. Altmark, S. Baturin
    LETI, Saint-Petersburg
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
 
 

The analysis of Vavilov-Cherenkov radiation generated by wide high current relativistic electronic bunch in a rectangular waveguide with multilayered dielectric filling is carried out. One ceramic layer of the structure possesses ferroelectric properties, which allow the waveguide frequency spectrum to be controlled by varying the permittivity of this ferroelectric layer by external electric field. On the basis of decomposition on orthogonal eigenmodes of a rectangular multilayered waveguide analytical expressions are received and numerical modeling of wakefield electromagnetic fields and the radial forces deflecting the bunch is spent.

 
THPD059 The Status of Turkish Accelerator Center Project 4419
 
  • S. Ozkorucuklu
    SDU, Isparta
  • A. Aksoy, B. Ketenoğlu, O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  • P. Arikan
    Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara
  • O. Cakir, A.K. Çiftçi, R. Çiftçi, K. Zengin
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  • H. Duran Yildiz
    Dumlupinar University, Faculty of Science and Arts, Kutahya
 
 

The status and road map of Turkish Accelerator Center (TAC) project is explained. TAC project is in third phase after feasibility and conceptual design phases with support of State Planning Organisation (SPO) of Turkey that the main aim of this phase is to complete of technical design report of TAC and to establish the first (test) facility. The first facility is planned as superconducting electron linac based IR FEL and bremsstrahlung facility. Third phase will be completed in 2013. It is planned that TAC will include a linac on ring type electron positron collider as a super charm factory, third and fourth generation light sources (SR and SASE FEL) and a proton facility. TAC collaboration is an inter-university collaboration of ten Turkish Universities under the coordination of Ankara University and TAC is a national project with international collaboration. In this study, the status of the project and the road map is explained with some results from design and construction studies.

 
THPD061 Nonlinear Theory of Wakefield Excitation in A Rectangular Multizone Dielectric Resonator 4422
 
  • G.V. Sotnikov, K.V. Galaydych
    NSC/KIPT, Kharkov
  • A.M. Naboka
    IERT, Kharkov
 
 

To excite intensive accelerating fields a multi-zone dielectric structures can be used*. As have shown already carried out researches, at their excitation by relativistic charged particle bunches the maximal amplitude of an accelerating field significantly depends on group velocity of energized waves. Till now these effects in wakefield multi-zone dielectric accelerators in details are not investigated. In addition the large charge of drive bunches requires the obligatory account of its space charge on bunch dynamics. To account the specified effects we built the nonlinear self-consistent theory of wake field excitation in the multilayered dielectric resonators. Expressions for excited fields, functionally depending on position of bunch particles in the resonator are found analytically. Excited fields are presented in the form of superposition solenoidal (LSE and LSM types) and potential fields. The nonlinear theory built in a general view is valid for any number of dielectric layers. Use of the constructed theory for the account of nonlinear and groups velocity effects is demonstrated on an example of 5-zone dielectric resonator with parameters close to experiment**.


* C. Wang et.al. In Proc. PAC 2005. IEEE, 2005, p. 1333.
** G.V.Sotnikov et.al. AIP Conf. proc. V.1086, p.415.

 
THPD062 Argonne Wakefield Accelerator Facility (AWA) Upgrades 4425
 
  • M.E. Conde, S.P. Antipov, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
    ANL, Argonne
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio
 
 

The AWA Facility is dedicated to the study of advanced accelerator concepts based on electron beam driven wakefields. The facility employs an L-band photocathode RF gun to generate high charge short electron bunches, which are used to drive wakefields in dielectric loaded structures, as well as in metallic structures. Accelerating gradients as high as 100 MV/m have been reached in dielectric structures, and RF pulses of up to 44 MW have been generated at 7.8 GHz. In order to reach higher accelerating gradients and higher RF power levels, several upgrades are underway: (a) a new RF gun with higher QE photocathode will replace the present drive gun; (b) the existing RF gun will generate a witness beam to probe the wakefields; (c) three new 25 MW L-band RF power stations will be added to the facility; (d) five additional linac structures will bring the beam energy up from 15 MeV to 75 MeV. The drive beam will consist of bunch trains of up to 32 bunches, with up to 60 nC per bunch. The goal of future experiments is to reach accelerating gradients of several hundred MV/m and to extract RF pulses with GW power level.

 
THPD063 Design and High Power Test of Photonic Bandgap Structures for Accelerator Applications 4428
 
  • B.J. Munroe, R.A. Marsh, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts
 
 

Photonic bandgap (PBG) structures show promising results for use in future collider applications. Both acceleration and wakefield damping have been demonstrated experimentally. The breakdown performance of a single cell PBG structure was tested at X-band at SLAC and found to have significant contributions from magnetic field effects. A new structure has been designed at 17.1 GHz to be tested at MIT to investigate the scaling of these and other breakdown effects with frequency. The 17.1 GHz structure will also use the open nature of the PBG lattice to greatly improve the breakdown diagnostics. Finally, a novel PBG structure has been designed for testing at SLAC using elliptical inner rods. This design significantly reduces the pulsed heating in the structure and should therefore improve the breakdown performance.

 
THPD066 Observation of Wakefields in a Beam-Driven Photonic Band Gap Accelerating Structure 4431
 
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio
  • S.P. Antipov, M.E. Conde, W. Gai, F. Gao, J.G. Power, Z.M. Yusof
    ANL, Argonne
  • H. Chen, C.-X. Tang, S.X. Zheng
    TUB, Beijing
  • P. Xu
    Tsinghua University, Beijing
 
 

Wakefield excitation has been experimentally studied in a 3-cell X-band standing wave Photonic Band Gap (PBG) accelerating structure. Major monopole (TM01- and TM02-like) and dipole (TM11- and TM12-like) modes were indentified and characterized by precisely controlling the position of beam injection. The quality factor Q of the dipole modes was measured to be ~10 times smaller than that of the accelerating mode. A charge sweep, up to 80 nC, has been performed, equivalent to ~30 MV/m accelerating field on axis. A variable delay low charge witness bunch following a high charge drive bunch was used to calibrate the gradient in the PBG structure by measuring its maximum energy gain and loss. Experimental results agree well with numerical simulations.

 
THPD067 The First Experiment of a 26 GHz Dielectric Based Wakefield Power Extractor 4434
 
  • C.-J. Jing, F. Gao, A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • M.E. Conde, W. Gai, R. Konecny, J.G. Power
    ANL, Argonne
 
 

High frequency, high power rf sources are needed for many applications in particle accelerators, communications, radar, etc. We have developed a 26GHz high power rf source based on the extraction of wakefields from a relativistic electron beam. The extractor is designed to couple out rf power generated from a high charge electron bunch train traversing a dielectric loaded waveguide. The first high beam experiment has been performed at Argonne Wakefield Accelerator facility. The experimental results successfully demonstrate the 15ns 26GHz rf pulse generated from the wakefield extractor with a bunch train of 16 bunches. Meanwhile, ~ 30MW short rf pulse has been achieved with a bunch train of 4 bunches. Beam Breakup has prevented charge transport through the power extractor beyond 10nC. We are doing simulations and developing methods to alleviate the BBU effect.

 
THPD068 Experiment on a Tunable Dielectric-Loaded Accelerating Structure 4437
 
  • C.-J. Jing, A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • M.E. Conde, W. Gai, J.G. Power
    ANL, Argonne
  • E. Nenasheva
    Ceramics Ltd., St. Petersburg
 
 

Dielectric-Loaded Accelerating (DLA) structures are generally lack of approaches to tune frequency after the fabrication. A tunable DLA structure has been developed by using an extra nonlinear ferroelectric layer. Dielectric constant of the applied ferroelectric material is sensitive to temperature and DC voltage. Bench test shows the +14MHz/°C, and 6MHz frequency tuning range for a 25kV/cm of DC bias field. A beam test is planned at Argonne Wakefield Accelerator facility before the IPAC conference. Detailed results will be reported.

 
THPD069 Studies of Nonlinear Media with Accelerator Applications 4440
 
  • P. Schoessow, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • S. Baturin
    LETI, Saint-Petersburg
  • V.P. Yakovlev
    Fermilab, Batavia
 
 

Materials possessing variations in the permittivity as a function of the electric field exhibit a variety of phenomena for electromagnetic wave propagation such as frequency multiplication, wave steepening and shock formation, solitary waves, and mode mixing. New low loss nonlinear microwave ferroelectric materials present interesting and potentially useful applications for both advanced and conventional particle accelerators. Accelerating structures (either wakefield-based or driven by an external rf source) loaded with a nonlinear dielectric may exhibit significant field enhancements. In this paper we will explore the large signal permittivity of these new materials and applications of nonlinear dielectric devices to high gradient acceleration, rf sources, and beam manipulation. We describe planned measurements using a planar nonlinear transmission line to characterize in detail the electric field dependence of the permittivity of these materials. We will present a concept for a nonlinear transmission line that can be used to generate short, high intensity rf pulses to drive fast rf kickers.

 
THPD070 Numerical and Experimental Studies of Dispersive, Active, and Nonlinear Media with Accelerator Applications 4443
 
  • P. Schoessow, C.-J. Jing, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • S.P. Antipov
    ANL, Argonne
 
 

Current advanced accelerator modeling applications require a more sophisticated treatment of dielectric and paramagnetic media properties than simply assuming a constant permittivity or permeability. So far active media have been described by a linear, frequency-dependent, single-frequency, scalar dielectric function.  We have been developing algorithms to model the high frequency response of dispersive, active, and nonlinear media. The work described also has applications for modeling of other electromagnetic problems involving realistic dielectric and magnetic media. Results to be reported include treatment of multiple Lorentz resonances based on auxiliary differential equation, Fourier, and hybrid approaches. We will also report on recent measurements of paramagnetic active microwave materials using EPR spectroscopy. Comparison of the results to numerical simulations will be presented.

 
THPD072 Laser Energy Conversion to Solitons and Monoenergetic Protons in Near-critical Hydrogen Plasma 4446
 
  • I. Pogorelsky, M. Babzien, M.N. Polyanskiy, V. Yakimenko
    BNL, Upton, Long Island, New York
  • N. Dover, Z. Najmudin, C.A.J. Palmer, J. Schreiber
    Imperial College of Science and Technology, Department of Physics, London
  • G. Dudnikova
    UMD, College Park, Maryland
  • M. Ispiryan, P. Shkolnikov
    Stony Brook University, StonyBrook
 
 

Recent theoretical and experimental studies point to better efficiency of laser-driven ion acceleration when approaching the critical plasma density regime. Simultaneously, this is the condition for observing solitons: "bubble"-like quasi-stationary plasma formations with laser radiation trapped inside. Exploring this regime with ultra-intense solid state lasers is problematic due to the lack of plasma sources and imaging methods at ~1021/cc electron density. The terawatt picosecond CO2 laser operated at Brookhaven's Accelerator Test Facility offers a solution to this problem. At 10 μm laser wavelength, the CO2 laser shifts the critical plasma density to 1019/cc which is attainable with gas jets and can be optically probed with visible light. Capitalizing on this approach, we focused a circular-polarized CO2 laser beam with a0=0.5 onto a hydrogen gas jet and observed monoenergetic proton beams in the 1 MeV range. Simultaneously, the laser/plasma interaction region has been optically probed with a 2nd harmonic picosecond Nd:YAG laser to reveal stationary soliton-like plasma formations. 2D PIC simulations agree with experimental results and aid in their interpretation.