Author: Rosenzweig, J.B.
Paper Title Page
MOOBN2 Inverse Free Electron Laser Accelerators for Driving Compact Light Sources and Detection Applications 1
 
  • A.M. Tremaine, S. Boucher, A.Y. Murokh
    RadiaBeam, Santa Monica, USA
  • S.G. Anderson
    LLNL, Livermore, California, USA
  • W.J. Brown
    MIT, Cambridge, Massachusetts, USA
  • J.P. Duris, P. Musumeci, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • I. Jovanovic
    Penn State University, University Park, Pennsylvania, USA
  • I. Pogorelsky, M.N. Polyanskiy, V. Yakimenko
    BNL, Upton, Long Island, New York, USA
 
  Funding: Defense Threat Reduction Agency (DTRA)
Because of the broad application space for compact, 1-2 GeV accelerators, Inverse Free Electron Lasers (IFELs) are enjoying a rebirth of R&D funding. The efforts are under way in industry (RadiaBeam), academia (UCLA), and national laboratories (LLNL and BNL) to develop an ultra-compact IFEL energy booster for the photoinjector driven linear accelerating systems. The RUBICON collaboration integrates many of the institutions for proof-of-principle IFEL driven Inverse Compton Scattering (ICS) compact light source demonstrations. IFELs perform optimally in this mid-energy range, and given continual advances in laser technology, high average power IFELs with gradients well over 500 MeV/m are now feasible, leading to high quality, compact ICS and Free Electron Laser light sources. Importantly, IFEL operation can have excellent shot-to-shot energy stability, which is crucial when not only driving these light sources, but also for the downstream applications such as photofission, nuclear resonance fluorescence and standoff detection.
 
slides icon Slides MOOBN2 [2.625 MB]  
 
MOP010 Resonance, Particle Stability, and Acceleration in the Micro-Accelerator Platform 121
 
  • J.C. McNeur, J.B. Rosenzweig, G. Travish, J. Zhou
    UCLA, Los Angeles, USA
  • R.B. Yoder
    Manhattanville College, Purchase, New York, USA
 
  Funding: US Defense Threat Reduction Agency
A micron-scale dielectric-based slab-symmetric accelerator is currently being designed and fabricated at UCLA. This Micro-Accelerator Platform (MAP) accelerates electrons in a 800nm wide vacuum gap via a resonant accelerating mode excited by a side-coupled optical-wavelength laser. Detailed results of particle dynamics and field simulations are presented. In particular, we examine various methods of achieving net acceleration and particle stability. Additionally, structural designs that produce accelerating fields synchronous with both relativistic and sub-relativistic electrons are discussed.
 
 
MOP011 Standing Wakefield Accelerator Based on Periodic Dielectric Structures 124
 
  • X. Wei, G. Andonian, J.B. Rosenzweig, D. Stratakis
    UCLA, Los Angeles, California, USA
 
  In recent years dielectric wakefield accelerators (DWA) have attracted significant attention for applications in high energy physics and THz radiation sources. However, one needs sufficiently short driving bunches in order to take advantage of the DWA's scaling characteristics to achieve high gradient and high frequency accelerating fields. Since a single large charge Q driving bunch is difficult to be compressed to the needed rms bunch length, a driving bunch train with smaller Q and small emittance, should be used instead for the DWA. In view of this senario, the group velocity of the excited wakefields needs to be decreased to nearly zero, so the electromagnetic energy does not vacate the structure during the bunch train. In this paper we propose a standing wakefield accelerator based on periodic dielectric structures, and address the difference between the proposed structure and the conventional DWA.  
 
MOP012 Ultra-High Gradient Compact S-Band Accelerating Structure 127
 
  • L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh
    RadiaBeam, Santa Monica, USA
  • V.A. Dolgashev
    SLAC, Menlo Park, California, USA
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • V. Yakimenko
    BNL, Upton, Long Island, New York, USA
 
  Funding: Dept. of Energy DE-SC0000866
In this paper, we present the radio-frequency design of the DECA (Doubled Energy Compact Accelerator) S-band accelerating structure operating in the pi-mode at 2.856 GHz, where RF power sources are commonly available. The development of the DECA structure will offer an ultra-compact drop-in replacement for a conventional S-band linac in research and industrial applications such as drivers for compact light sources, medical and security systems. The electromagnetic design has been performed with the codes SuperFish and HFSS. The choice of the single cell shape derives from an optimization process aiming to maximize RF efficiency and minimize surface fields at very high accelerating gradients, i.e. 50 MV/m and above. Such gradients can be achieved utilizing shape-optimized elliptical irises, dual-feed couplers with the "fat-lip" coupling slot geometry, and specialized fabrication procedures developed for high gradient structures. The thermal-stress analysis of the DECA structure is also presented.
* V. Dolgashev, "Status of X-band Standing Wave Structure Studies at SLAC", SLAC-PUB-10124, (2003).
** C. Limborg et al., "RF Design of LCLS Gun", LCLS-TN-05-03 (2005).
 
 
MOP057 A SLAB Dielectric Structure as a Source of Wakefield Acceleration and THz Cherenkov Radiation Generation 211
 
  • D. Stratakis, G. Andonian, J.B. Rosenzweig, X. Wei
    UCLA, Los Angeles, USA
 
  Funding: Work is funded by US Dept. of Energy grant numbers DE-FG03-92ER40693.
Acceleration of electrons in wakefields set up by a series of drive bunches in a dielectric structure has been proposed as a possible component of next-generation accelerators. Here, we discuss future experimental work with a slab sub-millimeter dielectric loaded accelerator structure that in contrast to conventional dielectric tubes should diminish the effects of transverse wakes and will permit higher total charge to be accelerated. The proposed experiment will allow the generation of unprecedented peak power at THz frequencies. In addition, it can generate ~50-150 MV/m drive fields and thus will allow the testing of acceleration using witness and drive beams. We examine details of the geometry and composition of the structures to be used in the experiment.
 
 
WEODS4 High Gradient Normal Conducting Radio-Frequency Photoinjector System for Sincrotrone Trieste 1504
 
  • L. Faillace, R.B. Agustsson, P. Frigola
    RadiaBeam, Santa Monica, USA
  • H. Badakov, A. Fukasawa, J.B. Rosenzweig, A. Yakub
    UCLA, Los Angeles, USA
  • F. Cianciosi, P. Craievich, M. Trovò
    ELETTRA, Basovizza, Italy
  • L. Palumbo
    Rome University La Sapienza, Roma, Italy
  • B. Spataro
    INFN/LNF, Frascati (Roma), Italy
 
  Radiabeam Technologies is leading a multi-organizational collaboration by UCLA, INFN and MATS to deliver a high gradient normal conducting radio frequency (NCRF) 1.6 cell photoinjector system to the Sincrotrone Trieste facility. Designed to operate with a 120MV/m accelerating gradient, this dual feed, fat lipped racetrack coupler design is modeled after the LCLS photoinjector with a novel demountable cathode which permits cost effective cathode exchange. Full overview of the project to date will be discussed along with basic, design, engineering, manufacturing and RF test results.  
slides icon Slides WEODS4 [3.186 MB]  
 
THP050 Normal Conducting Radio Frequency X-band Deflecting Cavity Fabrication and Validation 2211
 
  • R.B. Agustsson, S. Boucher, L. Faillace, P. Frigola, A.Y. Murokh, S. Storms
    RadiaBeam, Santa Monica, USA
  • D. Alesini
    INFN/LNF, Frascati (Roma), Italy
  • V.A. Dolgashev, R.J. England
    SLAC, Menlo Park, California, USA
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • V. Yakimenko
    BNL, Upton, Long Island, New York, USA
 
  An X-band Traveling wave Deflector mode cavity (XTD) has been developed at Radiabeam Technologies to perform longitudinal characterization of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. The XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, fabrication and RF validation and tuning will be presented.  
 
THP164 Orbital Angular Momentum Light Generated via FEL at NLCTA 2420
 
  • A. Knyazik, E. Hemsing, A. Marinelli, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
 
  A scheme to create coherent light with orbital angular momentum (OAM) using Free Electron Laser (FEL) at NLCTA is proposed. An 795 nm light co-propagating with relativistic unmodulated electron beam is fed through a helical undulator tuned to the second harmonic of the laser, which acts as a pre-buncher that helically micro-bunches the beam, modulating it in energy. The energy modulation is transferred to helical density modulation by propagating through a longitudinally dispersive section, such as a chicane. Finally the helical density 3-D modulated electron beam is sent through a second undulator resonant at light’s fundamental frequency, causing the electron beam to radiate OAM light. NLCTA facility has everything to make this experiment, including a planar undulator tuned to the fundamental frequency, except for a helical pre-bunching undulator, which can be easily constructed and installed to generate OAM light at NLCTA. According to simulations generated with Mathematica 7 and Genesis 1.3 a 3 period long pre-buncher will be enough to get out 140 MW of laser power from a seeded 10 MW, after transversing a 1.5 m long planar radiator using electron beam generated by NLCTA.  
 
TUODS4
Free Electron Laser Seeding Experiments at SPARC  
 
  • L. Giannessi, F. Ciocci, G. Dattoli, M. Del Franco, A. Petralia, M. Quattromini, C. Ronsivalle, I.P. Spassovsky, V. Surrenti
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • D. Alesini, M. Bellaveglia, M. Castellano, E. Chiadroni, G. Di Pirro, M. Ferrario, D. Filippetto, A. Gallo, G. Gatti, A. Ghigo, E. Pace, B. Spataro, C. Vaccarezza
    INFN/LNF, Frascati (Roma), Italy
  • A. Bacci, A.R. Rossi, L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • M. Bougeard, B. Carré, D. Garzella
    CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
  • F. Briquez, M.-E. Couprie, M. Labat
    SOLEIL, Gif-sur-Yvette, France
  • A. Cianchi
    Università di Roma II Tor Vergata, Roma, Italy
  • F. Frassetto, L. P. Poletto
    LUXOR, Padova, Italy
  • G. Lambert
    LOA, Palaiseau, France
  • G. Marcus, P. Musumeci, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • M. Migliorati, A. Mostacci, L. Palumbo
    Rome University La Sapienza, Roma, Italy
  • M. Moreno, M. Serluca
    INFN-Roma, Roma, Italy
  • V. Petrillo
    Universita' degli Studi di Milano, Milano, Italy
  • J.V. Rau, V. Rossi Albertini
    ISM-CNR, Rome, Italy
  • E. Sabia
    ENEA Portici, Portici (Napoli), Italy
  • S. Spampinati
    ELETTRA, Basovizza, Italy
 
  We report on the recent activity at SPARC, which has successfully been operated in seeded mode. In the framework of the DS4 EUROFEL collaboration, a research work plan aiming at the investigation of seeded and cascaded FEL configurations was implemented. The main goal of the collaboration was to study the amplification and the harmonic generation process of an input seed signal. We describe here the first experimental results, with the observation of harmonics up to the 11th of the fundamental and the operation of the FEL in cascaded mode, driven both by seed generated in crystal and in gas (Ar).  
slides icon Slides TUODS4 [8.947 MB]