MC3: Novel Particle Sources and Acceleration Techniques
A15 New Acceleration Techniques
Paper Title Page
MOXPLM2 From Dreams to Reality: Prospects for Applying Advanced Accelerator Technology to Next Generation Scientific User Facilities 1
 
  • M. Ferrario
    INFN/LNF, Frascati, Italy
  • R.W. Aßmann
    DESY, Hamburg, Germany
 
  Recent years have seen spectacular progress in the development of innovative acceleration methods that are not based on traditional RF accelerating structures. These novel developments are at the interface of laser, plasma and accelerator physics and may potentially lead to much more compact and economical accelerator facilities. While primarily focusing on the ability to accelerate charged particles with much larger gradients than traditional RF, these new techniques have yet to demonstrate comparable performances to RF in terms of both beam parameters or reproducibility. To guide the developments beyond the necessary basic R&D and concept validations, a common understanding and definition of required performance and beam parameters for an operational user facility is now needed. These innovative user facilities can include "table-top" light sources, medical accelerators, industrial accelerators or even high-energy colliders. The talk will review the most promising developments in new acceleration methods, it will present the status of ongoing projects including the EU project EuPRAXIA and will identify the set of required specifications for the application under consideration.  
slides icon Slides MOXPLM2 [16.331 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOXPLM2  
About • paper received ※ 19 May 2019       paper accepted ※ 16 June 2019       issue date ※ 21 June 2019  
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WEZPLS1 Control of Laser Plasma Accelerated Electrons: A Route for Compact Free Electron Lasers 2280
 
  • M.-E. Couprie, T. André, F. Blache, F. Bouvet, F. Briquez, Y. Dietrich, J.P. Duval, M. El Ajjouri, A. Ghaith, C. Herbeaux, N. Hubert, C.A. Kitegi, M. Labat, N. Leclercq, A. Lestrade, A. Loulergue, O. Marcouillé, F. Marteau, D. Oumbarek Espinos, P. Rommeluère, M. Sebdaoui, K.T. Tavakoli, M. Valléau
    SOLEIL, Gif-sur-Yvette, France
  • I.A. Andriyash, S. Corde, J. Gautier, J.-P. Goddet, O. S. Kononenko, G. Lambert, K. Ta Phuoc, A. Tafzi, C. Thaury
    LOA, Palaiseau, France
  • S. Bielawski, C. Evain, E. Roussel, C. Szwaj
    PhLAM/CERLA, Villeneuve d’Ascq, France
  • V. Malka
    Weizmann Institute of Science, Physics, Rehovot, Israel
 
  The recent spectacular development of laser plasma ac- celerators that now can deliver GeV electron beams in an extremelyshortdistancemakesthemverypromising. Ap- plications for light sources based on undulator radiation and free electron laser appear as an intermediate step to move from an acceleration concept to an accelerator qual- ification. However, the presently achieved divergence and energy spread require some electron beam manipulations. The COXINEL test line was designed for enabling Free Elec- tron Laser operation with baseline reference parameters. It comprises variable permanent magnet quadrupoles for di- vergence handling, a magnetic chicane for electron energy sorting, a second set of quadrupole for chromatic focusing and an undulator for synchrotron radiation emission and/or free electron laser gain medium. The transport along the line is controlled [1]. The synchrotron radiation emitted by the undulator radiation is studied under different conditions of detection (CCD camera, spectrometer), electron beam manipulation and undulator parameters. These observations pave the way towards Laser Plasma Acceleration based Free Electron Laser.

[1] T. André et al., Control of laser plasma accelerated electrons for light sources, accepted in Nature Comm.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEZPLS1  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEZZPLS3 Longitudinal-Phase-Space Manipulation for Efficient Beam-Driven Structure Wakefield Acceleration 2296
SUSPFO040   use link to see paper's listing under its alternate paper code  
 
  • W.H. Tan, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • A. Zholents, A. Zholents
    ANL, Argonne, Illinois, USA
 
  Funding: This work is funded by the United States Department of Energy awards DE-SC0018656 with Northern Illinois University and DE-AC02-06CH11357 with Argonne National Laboratory.
Collinear beam-driven structure wakefield acceleration (SWFA) is an advanced acceleration technique that could support the compact generation of high-energy beams for future multi-user x-ray free-electron-laser facilities*. Producing an ideal shaped drive beam through phase space manipulation is crucial for an efficient SWFA. Controlling the final longitudinal-phase space of the drive beam necessitate staged beam manipulations during acceleration. This paper describes the preliminary design of an accelerator beamline capable of producing drive beam with tailored current distribution and longitudinal-phase-space correlation. The proposed design is based on simple analytical models combined in a 1-D longitudinal beam-dynamics simulation tracking program supporting forward and backward (time reversal) tracking.
* A. Zholents, et al., Dielectric wakefield accelerator to drive the future FEL light source
 
slides icon Slides WEZZPLS3 [2.869 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEZZPLS3  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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THPGW001 Design of LhARA - Laser Hybrid Accelerator for Radiobiological Applications 3578
 
  • J. Pasternak
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • O. Ettlinger, C. Hunt, A. Kurup, K.R. Long, Z. Najmudin, J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • H.T. Lau
    EBG MedAustron, Wr. Neustadt, Austria
 
  Recent developments of using lasers interacting with targets for the creation of ion beams offer a possibility to provide beams for radiobiology research. This research aims to precisely study the radiobiological effectiveness of charged particles on various cultures of cells, which is essential to inform next generation hadron therapy treat-ment plans. The Laser hybrid Accelerator for Radiobio-logical Applications (LhARA) has been proposed to use a laser driven beam, which will be captured and focused using Gabor Lenses. The beam will be then energy and momentum selected to create a beam for in-vitro cells studies or sent to a post-accelerator ring to create beam for in-vivo studies. The optical design of LhARA is pre-sented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW001  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW004 The Use of an RF Undulator in the Design of an Accelerating Structure 3587
 
  • N.V. Avreline
    TRIUMF, Vancouver, Canada
  • P.G. Alexey, S.M. Polozov
    MEPhI, Moscow, Russia
 
  The idea of accelerating a beam in the accelerating structures based on an RF undulator poses great advantages in high current proton and ions accelerators. The accelerating structure based on an RF undulator uses a combinational wave that consists of the zeroth and the first harmonics for acceleration and focusing. This paper presents the development of this accelerating structure for acceleration of a beam. In particular, we show that this structure is an H-type resonator composed from five coupled sections.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW004  
About • paper received ※ 01 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPGW011 Commissioning-Stages and Radio-Protection Concept for the THz-Linac Based Accelerator "AXSIS" at DESY 3598
 
  • F. Burkart, R.W. Aßmann, U. Dorda, B. Marchetti
    DESY, Hamburg, Germany
  • F.X. Kärtner, N.H. Matlis, T. Rohwer
    CFEL, Hamburg, Germany
 
  The dedicated accelerator R&D facility SINBAD at DESY hosts the AXSIS accelerator. This project is funded by the European Research Council to develop a compact source for attosecond serial X-ray crystallography and spectroscopy. For that purpose, in one of the arcs of the SINBAD facility and the neighboring laser labs, an accelerator research site is being constructed where a fully THz-driven accelerator (electron gun and linac, < 30MeV) will be installed. The current status of the hardware installation of the electron beam accelerator is presented. Furthermore, the required radio-protection measures and maximum beam parameters are presented. In this contribution the commissioning plans and the staging of the beam operation for the accelerator complex will be shown and discussed in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW011  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPGW014 Tolerance Studies and Limitations for Photonic Bandgap Fiber Accelerators 3605
 
  • L. Genovese, R.W. Aßmann, U. Dorda, M. Kellermeier, W. Kuropka, F. Lemery, F. Mayet
    DESY, Hamburg, Germany
  • W. Kuropka, F. Mayet
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  Laser-driven hollow core photonic bandgap (PBG) fibers were proposed by Lin in 2001 as high-gradient accelerators. The central defect in the transversely periodic lattice supports an accelerating mode for synchronous acceleration in the ultra-relativistic regime. The optical frequencies in such dielectric laser accelerators motivate a sensitivity and tolerance study to overcome manufacturing imperfections. Finally we discuss the propagation characteristics of Lin-fibers and find that small-bandwidth (~ns) pulses would be needed for efficient acceleration over longer distances.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW014  
About • paper received ※ 16 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPGW029 Crucial Transverse Beam Dynamics of the Racetrack-shape Fixed Field Induction Accelerator for Giant Cluster Ions 3643
 
  • T. Taufik
    BATAN, Yogyakarta, Indonesia
  • T. Adachi, K. Takayama, M. Wake
    KEK, Ibaraki, Japan
 
  A racetrack-shape fixed field induction accelerator (RAFFIA) for high energy giant cluster ion acceleration was proposed in 2015*. The RAFFIA employs 4 bending magnets with gradient in the main pole face and reverse field strip at its front side which generate strong focusing in both planes. Beam dynamics properties of the RAFFIA of 140 MeV for C-60 have been evaluated by linear optics. The result has been confirmed with a help of 3D macro-particle computer simulation**. It is identified that the issue of COD generated from field non-uniformity associated with a finite size of the bending magnet is inherent. The programmed COD correction by steering magnets are discussed as well as the importance of uniformity in the magnet field profile. So far it has been unknown what beam current is acceptable in the RAFFIA. In order to estimate space-charge effects in the RAFFIA under design, the 2D core (σ) evolution equation has been derived from the envelope equation perturbed by space-charge fields. Resonant structures and chaotic motion in the phase space of (σ,σ’) have been clarified as a function of beam current. Those results were justified by macro-particle tracking based on a renormalized transfer matrix approach***. As a result, it turns out that the 8+ C-60 beam of 200 uA is acceptable.
* K.Takayama, et. al, Phys. Rev. ST Accel. Beams 18, 050101 (2015).
** Taufik, et. al, sub. to Phys. Rev. AB (2018).
*** Taufik, K.Takayama, and T. Adachi, sub. Phys. Rev. AB (2019).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW029  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPGW033 Numerical Study of Photonic-Crystal-Based Dielectric Accelerators 3653
 
  • G. Torrisi, L. Celona, S. Gammino, D. Mascali, G. Sorbello
    INFN/LNS, Catania, Italy
  • C. De Angelis, A. Locatelli
    University of Brescia, Brescia, Italy
  • G.S. Mauro
    INFN/LNL, Legnaro (PD), Italy
  • G. Sorbello
    University of Catania, Catania, Italy
 
  All-dielectric electromagnetic band gap (EBG) waveguides structures promise significant improvement of accelerating gradient of laser-driven acceleration with the potential to miniaturize the accelerator itself. In this work we study photonic crystal structures designed for acceleration of relativistic electrons. We explore the performance of the all-dielectric EBG accelerating waveguide structures thanks to full wave electromagnetic simulations of couplers and accelerating waveguides. The characteristic interaction impedance, accelerating gradient and all the key parameters that are typically used to characterize linear accelerators are evaluated and used to compare the properties of the accelerating mode field distribution in different geometries.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW033  
About • paper received ※ 30 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW042 Applications of Compact Laser Plasma Accelerator (CLAPA) Beamline in Peking University 3676
SUSPFO059   use link to see paper's listing under its alternate paper code  
 
  • D.Y. Li, J.E. Chen, Y.X. Geng, X.Y. Hu, C.C. Li, Q. Liao, C. Lin, H.Y. Lu, W.J. Ma, M.J. Wu, X.H. Xu, X.Q. Yan, T. Yang, Y.Y. Zhao, J.G. Zhu, K. Zhu
    PKU, Beijing, People’s Republic of China
 
  Proton beam with energies less than 10 MeV, <1% energy spread, several to tens of pC charge can be stably produced and transported in Compact LAser Plasma Accelerator (CLAPA) at Peking University. The CLAPA beam line is an object-image point analysing system, which ensures the transmission efficiency and energy selection accuracy for proton beams with initial large divergence angle and energy spread. A spread-out Bragg peak (SOBP) is produced with high precision beam control, which is essential for cancer therapy. Other primary application experiments based on laser-accelerated proton beam have also been carried out, such as proton radiograph, stress testing for tungsten, irradiation of semi-conductor sensor to simulate the space irradiation environment and so on.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW042  
About • paper received ※ 15 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPGW043 Conceptual design of a MeV Ultrafast Electron Diffraction Based on 1.4 Cell RF Gun 3679
SUSPFO061   use link to see paper's listing under its alternate paper code  
 
  • J.J. Li, H.M. Chen, K. Fan, Y. Song, P. Yang, Y.T. Yang
    HUST, Wuhan, People’s Republic of China
 
  Ultrafast Electron Diffraction (UED) is a powerful tool to investigate the dynamic structure with temporal scale of 100 femtoseconds and spatial scale of atomic length. To achieve high quality diffraction patterns, the transverse emittance and the longitudinal length of electron bunches should be reduced. MeV UED, using photocath-ode RF gun instead of traditional DC gun, is being developed to produce high quality electron bunches with lower emittance and shorter length. We are developing a MeV UED facility based on a 1.4 cell photocathode RF gun that can provide higher acceleration gradient at Huazhong University of Science and Technology. In this paper, the conceptual design of the MeV UED is pro-posed with typical parameters of the system, as well as the ASTRA simulation results of optimization.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW043  
About • paper received ※ 11 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPGW045 A Simple Way to Introduce an Ajustable Femtosecond Pre-Pulse to Enhance Laser-Driven Proton Acceleration 3686
SUSPFO073   use link to see paper's listing under its alternate paper code  
 
  • P. J. Wang, Z.X. Cao, Y.X. Geng, D.F. Kong, C. Lin, J B. Liu, H.Y. Lu, W.J. Ma, Z.S. Mei, Z.P. Pan, Y.R. Shou, D. H. Wang, S.R. Xu, X.Q. Yan, Y.Y. Zhao
    PKU, Beijing, People’s Republic of China
  • G.Y. Gao
    LMU, Garching, Germany
 
  We demonstrate a simple way to introduce a femtosecond pre-pulse with adjustable intensity and delay without using an additional compressor to enhance laser-driven proton acceleration. Targets with different thicknesses were shoot at normal incidence by varying the pre-pulses. Experimental results show that significant enhancement on the proton energy can be achieved when the intensity of pre-pulse is optimized. Density profile of preplasma was obtained by bydrodynamic simulations. PIC simulations reveal that the preplasma generated by a femtosecond pre-pulse can increase the intensity of main pulse.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW045  
About • paper received ※ 30 April 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019  
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THPGW047 Cylindrical Cavity Design and Particle-Tracking Simulation in Cyclotron Auto-Resonance Accelerator 3689
SUSPFO080   use link to see paper's listing under its alternate paper code  
 
  • Y.T. Yuan
    HUST, Wuhan, People’s Republic of China
  • K. Fan
    Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
  • Y. Jiang
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
 
  The Cyclotron Auto-Resonance Accelerator (CARA) is a novel concept of accelerating continuous-wave (CW) charged-particle beams. This type of accelerator has ap-plications in environment improvement area and genera-tion of high-power microwaves. In CARA, the CW elec-tron beam follows a gyrating trajectory while undergoing the interaction with a rotating TE11-mode RF field and tapered static magnetic field. The cylindrical cavity oper-ating at TE11p-mode is adapted to accelerate electron beam. The cavity size is optimized to obtain a beam with designed energy, then a design method of the TE11p-mode acceleration cavity is described here. Moreover, regard-less of space charge effect, several particle-tracking simu-lations of CARAs are showed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW047  
About • paper received ※ 16 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPGW073 Status on a Laser Injection in Beam Driven Dielectric Wakefield Accelerator Experiment 3761
 
  • G. Andonian, T.J. Campese, F.H. O’Shea
    RadiaBeam, Santa Monica, California, USA
  • D.L. Bruhwiler, N.M. Cook
    RadiaSoft LLC, Boulder, Colorado, USA
  • M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • T. Xu
    Northern Illinois University, DeKalb, Illinois, USA
 
  The generation of high-brightness beams with ultra-low emittance using the plasma photocathode technique has gained significant traction in recent years. The practical execution of a combined plasma wakefield acceleration section and a laser injected typically requires a dual gas medium for precision ionization of low and high ionization thresholds. The concept can be partially simplified in experiment by replacing the plasma wakefield acceleration component with a dielectric wakefield acceleration scheme, sacrificing field gradient but maintaining low emittance beam generation. In this paper, we describe the progress on the design of a hybrid scheme, using laser injection in a gas medium within a dielectric wakefield accelerator structure. The proof-of-concept experiment is planned to take place at the Argonne Wakefield Accelerator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW073  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPGW078 Prototyping of Brazed mm-Wave Accelerating Structures 3764
 
  • M. A. K. Othman, B. J. Angier, A.A. Haase, E.A. Nanni, M. R. Roux, A.V. Sy
    SLAC, Menlo Park, California, USA
 
  Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515. This work was also supported by NSF grants PHY-1734015.
Advanced fabrication and prototyping of metallic RF structures play a fundamental role in advancing accelerator technologies particularly at mm-wave and THz frequencies. With the scaling of the RF structure up to these frequencies, conventional fabrication techniques do not achieve the required accuracy and tolerances. Improved manufacturing techniques including diffusion bonding, brazing or clamping split-block geometries produce high quality structures when successfully implemented. However, in most schemes the resulting gap and irregularities at the iris result in a local field enhancement which is not desirable for high-gradient operation. Development of advanced split-block braze technique for THz accelerators was required for high quality miniature accelerators. A new braze technique was developed for W-band structures to control the flow of braze alloy, enabling fabrication of the first high-gradient brazed structures at mm-wave frequencies. This fabrication process has the potential to overcome consistent fabrication defects around the cell iris. Thin spacers were used to set the final gap between blocks during the braze process; while braze foil thickness is varied with minimal impact on the resulting frequency. To demonstrate the robustness of this technique, testing after the various manufacturing steps was done to monitor and track frequency change throughout the process. This technique is further pushed to produce G-band RF structures, operating at 300 GHz.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW078  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPGW079 THz-Based Femtosecond MeV Electron Bunch Compression 3766
 
  • M. A. K. Othman, M.C. Hoffmann, M.E. Kozina, R.K. Li, E.A. Nanni, X. Shen, E.J. Snively, X.J. Wang
    SLAC, Menlo Park, California, USA
 
  Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515.
Probing structural dynamics at atomic spatial and ultrashort temporal scales reveals unprecedented details of fundamental behavior of nature, allowing for better understanding of intricate energy-matter interaction occurring at such scales. Developing state-of-the-art technology to access these details entails utilizing X-ray free-electron lasers (XFELs), ultrafast electron diffraction (UED), and advanced electron microscopes. In particular, ultrafast diffraction science received growing attention thanks to innovation in sources, detectors and instrumentation in general. Within this context, interest in laser-generated THz wave-matter interaction has recently emerged as a new regime for controlling electrons with high temporal precision. Previously, the SLAC UED team has demonstrated attosecond electron metrology using laser-generated single-cycle THz radiation, which is intrinsically phase locked to the optical drive pulses, to manipulate multi-MeV relativistic electron beams. Here we demonstrate further steps towards achieving ultrafast timing resolution that utilizes femtosecond electron bunches. The proposed setup allows for compressing electron beam bunches down to a femtosecond using interaction with high field single-cycle THz pulses. We demonstrate a novel design of a dispersion-free parallel-plate tapered waveguide that provides focusing of THz pulses achieving >100 MV/m field strength at the interaction point as measured by electro-optical sampling for ~7 μJ of incoming THz pulse energy. The structure is being designed and built for bunch compression experiments using the SLAC UED facility.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW079  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW080 Initial Results of High-Gradient Breakdown Tests for W-Band Accelerating Structures 3769
 
  • M. A. K. Othman, V.A. Dolgashev, A.A. Haase, E.A. Nanni, J. Neilson, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  • S. Jawla, J.F. Picard, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  • S. C. Schaub
    MIT, Cambridge, Massachusetts, USA
  • B. Spataro
    INFN/LNF, Frascati, Italy
 
  Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515 (SLAC) and grant DE-SC0015566 (MIT). This work was also supported by NSF grants PHY-1734015.
Emerging accelerator technology at mm-wave and THz frequencies has recently shown notable progress. Indeed, metallic and dielectric accelerating structures at THz frequencies are plausible candidates toward miniaturization of accelerators. RF breakdown in such structures is a major factor limiting their performance. Therefore, comprehensive analysis of RF breakdown physics in mm-wave accelerating structures is needed, which includes understanding of dependencies of the breakdown rate on geometric, electromagnetic and material properties. In this work we report on high power tests of a 110 GHz single-cell standing wave accelerating structure powered by a 1 MW gyrotron. The RF power is coupled from the gyrotron into the accelerating structure with a Gaussian to TM01 mode converter through a quasi-optical setup. We demonstrate coupling of 10 ns, 100s of kilowatt pulses into the structure using a fast switch and achieving ~150 MV/m accelerating gradients. Measurements of RF signals and field-emitted currents allow for complete comprehensive of the high-gradient behavior of W-band structures, including breakdown probability.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW080  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW088 Transformer Ratio Measurements from Ramped Beams in the Plasma Blowout Regime using Emittance Exchange 3778
SUSPFO134   use link to see paper's listing under its alternate paper code  
 
  • R.J. Roussel, G. Andonian, W.J. Lynn, J.B. Rosenzweig
    UCLA, Los Angeles, USA
  • M.E. Conde, D.S. Doran, G. Ha, J.G. Power, C. Whiteford, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • J. Seok
    UNIST, Ulsan, Republic of Korea
 
  Funding: Work is supported by DOE contract DE-SC0017648.
We present initial measurements from a UCLA-Argonne Wakefield Accelerator collaborative plasma wakefield acceleration (PWFA) experiment aimed at demonstrating the dependence of transformer ratio on longitudinal beam shape. The transformer ratio or the ratio between the maximum acceleration of the witness and the maximum deceleration of the drive beam, is key to a mature, beam-based, plasma wakefield accelerator design. Utilizing the unique capabilities of the emittance exchange (EEX) beamline, we may obtain transformer ratios in excess of six in PWFA. We present the experimental beamline design, relevant beam diagnostics and explore preservation of the longitudinal beam profile.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW088  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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