MC3: Novel Particle Sources and Acceleration Techniques
A16 Advanced Concepts
Paper Title Page
MOPMP009 Effect of Initial Parameters on the Super Flat Beam Generation with the Phase-Space Rotation for Linear Colliders 442
 
  • M. Kuriki, R. Tamura
    HU/AdSM, Higashi-Hiroshima, Japan
  • H. Hayano, X.J. Jin, T. Konomi, Y. Seimiya, N. Yamamoto
    KEK, Ibaraki, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • J.G. Power
    ANL, Argonne, Illinois, USA
  • K. Sakaue
    The University of Tokyo, The School of Engineering, Tokyo, Japan
  • M. Washio
    RISE, Tokyo, Japan
 
  Funding: This work is partly supported by Japan-US Cooperative grant for scientific studies, Grant aid for scientific study by MEXT Japan (KAKENHI) Kiban B.
Linear collider is a concept to realize e+e collision beyond the limitation of the ring colliders by the synchrotron radiation. To obtain an enough luminosity, eg. 1.0·10+34 cm-2sec-1, the beam is focused down to nano-meter size with a high aspect ratio. This super flat beam is useful to improve the luminosity and to compensate the beam-beam effect, eg. Beamstrahlung. In a conventional design, the super-flat beam is produced by radiation damping in a storage ring. We propose to produce this super-flat beam with phase-space rotation techniques. We employ both Round to Flat Beam Transformation and Transverse to Longitudinal Emittance eXchange, the super flat beam can be generated by controlling the space-charge effect which spoiled the performance. We present the RFBT performance with respect to the initial conditions, i.e. beam size, initial emittance, solenoid field (strength and profile), etc.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP009  
About • paper received ※ 13 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPRB013 Focusing of High-Brightness Electron Beams with Active-Plasma Lenses 601
 
  • R. Pompili
    INFN/LNF, Frascati, Italy
 
  Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB013  
About • paper received ※ 13 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPRB056 THz Radiator Based on Photonic Band Gap Crystal for SwissFEL 693
 
  • L. Shi, R. Ischebeck, S. Reiche
    PSI, Villigen PSI, Switzerland
 
  Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701647.
The electromagnetic radiation in 1-20 THz has many unique properties when it interacts with matter due to its non-ionizing excitation in matter. Especially the dynamics of the excited matter can be probed with the help of X-ray pulses at a free electron laser facility, e.g. SwissFEL, to deepen our understanding of a wide range of phenomena. Due to its high research potential, various means of THz generation have been proposed and demonstrated. We investigate preliminarily here its generation based on a relativistic electron bunch and a photonic band gap crystal (PBG) made of dielectric rods. The PBG provides additional degrees of freedom for the THz pulse tuning. Additionally, the unwanted radiation parts can be damped by the structure in order to minimize the deleterious beam dynamics effects. The crystal also promises the integration of generation, filtering and coupling for transport into a single piece.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB056  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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MOPRB062 nuSTORM Decay Ring 716
 
  • J.-B. Lagrange
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • R.B. Appleby, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • J. Pasternak
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
 
  Precise neutrino cross section measurements and search for sterile neutrinos can be done with neutrino beams produced from muons decaying in a storage ring due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a racetrack storage ring, where circulating muon beam would be captured. The storage ring has three options: a FODO solution with large aperture quadrupoles, a racetrack FFA (Fixed Field Alternating gradient) using the recent developments in FFAs and a hybrid solution of the two previous options. Machine parameters, linear optics design and beam dynamics of the hybrid solution are discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB062  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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MOPRB067 High-gradient Single Cycle Terahertz Accelerating Structures 731
 
  • S.P. Antipov, E. Gomez, S.V. Kuzikov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
 
  Recently, gradients on the order of 1 GV/m level have been obtained in a form of single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). These pulses however are broadband (0.1-5 THz) and therefore a new accelerating structure type is required. For electron beam acceleration with such pulses we propose arrays of parabolic focusing micro-mirrors with common central. These novel structures could be produced by a femtosecond laser ablation system developed at Euclid Techlabs. This technology had already been tested for production of several millimeters long, multi-cell structure which has been testing with electron beam. We also propose using of structures where necessary GV/m E-fields are excited by a drive bunch travelling in the corrugated waveguide. The radiated by drive bunch sequence of short range delayed wakes are guided in this case by metallic disks and reflected back being focused exactly at time when the witness bunch arrives.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB067  
About • paper received ※ 21 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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MOPRB069 Generation of High Power Short Rf Pulses using an X-Band Metallic Power Extractor Driven by High Charge Multi-Bunch Train 734
 
  • J.H. Shao, M.E. Conde, D.S. Doran, G. Ha, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • H.B. Chen, M.M. Peng, J. Shi, H. Zha
    TUB, Beijing, People’s Republic of China
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • J. Seok
    UNIST, Ulsan, Republic of Korea
 
  Short pulse two-beam acceleration (TBA) is a structure wakefield acceleration (SWFA) approach aiming to achieve gradient above 250 MV/m using rf pulses less than 20 ns. An X-band 11.7 GHz metallic power extractor has been developed as the power source to test accelerating structures in this extreme regime. The power extractor is designed to be driven by high charge bunches separated by 769.2 ps (9 times the X-band period) on an L-band 1.3 GHz beamline. In the recent experiment, ~280 MW rf pulses with 3 ns flat-top have been measured by a coaxial rf pickup when driven by 8-bunch trains with a total charge of ~500 nC. The power level is ~50% lower than the theoretical prediction and simulation. Experimental investigation suggests that the missing power was mainly caused by the multipacting issue inside the rf pickup, which could be eliminated by a newly-designed directional coupler.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB069  
About • paper received ※ 19 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPRB087 Proposal for a High Transformer Ratio CW Dielectric Accelerator 773
 
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
  • J.C. Brutus, Y.C. Jing, I. Pinayev, G. Wang
    BNL, Upton, Long Island, New York, USA
  • M.E. Conde, C.-J. Jing, J.G. Power
    ANL, Argonne, Illinois, USA
  • A. Kanareykin
    Euclid Beamlabs LLC, Bolingbrook, USA
  • N. Vafaei
    UCLA, Los Angeles, California, USA
 
  Advanced CW accelerators are one of high priority directions identified by Advanced Accelerator Concepts Research Roadmap Workshop Report *. High transformer ratio of beam-driven accelerators is critically important for cost-effective FEL systems. We present a proposed experiment for demonstrating a high transformer ratio CW dielectric accelerator using operational SRF accelerator built for Coherent electron Cooling experiment. This accelerator operates with CW electron beam comprised of 78 kHz train of electron bunches. Electron bunches with controllable longitudinal and charge up to 10 nC per bunch are generated in 1.25 MV SRF photo-electron gun. This bunches are ballistically compressed to duration of 10-to-30 psec and accelerated to 15 MeV in SRF linac**. Such bunches would be excellent drivers of high-transformer ratio DWA accelerators. In this paper we present expected performance of proposed CW DWA accelerator.
*Advanced Accelerator Concepts Research Roadmap Workshop Report, 2016,
*V.N. Litvinenko et al., In proc.of FEL’17, Santa Fe, NM, USA, August 20-25, 2017, p. 132
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB087  
About • paper received ※ 19 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUXXPLS3 The Design Optimization of the Dielectric Assist Accelerating Structure for Better Heat and Gas Transfer 1179
 
  • S. Mori, M. Yoshida
    KEK, Ibaraki, Japan
  • D. Sato
    AIST, Tsukuba, Ibaraki, Japan
 
  The dielectric-assist accelerating (DAA) structure is a dielectric-inserted normal-conducting cavity, which provides high Q value at room temperature. This accelerating structure is composed of dielectric disks and a dielectric cylindrical layer inserted in a copper cavity. For the realistic operation, the removal of heat from the dielectric cells and the vacuum evacuation of gas inside the cylindrical layers have not considered yet. In order to solve the problems, we propose the optimized design of the DAA structure, where the extended part of the dielectric disk is embedded in the copper cavity and the choke structure is applied. We show the result of the electromagnetic-field simulation of the extended DAA structure and the thermal simulation to clarify the relation between a duty factor and maximum temperature of the dielectric cells.  
slides icon Slides TUXXPLS3 [5.892 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS3  
About • paper received ※ 30 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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