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Rosenzweig, J.B.

Paper Title Page
MOPE092 Ultrashort Bunch Length Diagnostic with Sub-femtosecond Resolution 1200
 
  • G. Andonian
    RadiaBeam, Marina del Rey
  • G. Andonian, E. Hemsing, P. Musumeci, J.B. Rosenzweig, S. Tochitsky
    UCLA, Los Angeles, California
 
 

For successful operation and beam characterization, fourth generation light sources require the observation of sub-picosecond bunches with femtosecond resolution. In this paper, we report on the design and development of a novel technique to achieve sub-femtosecond temporal resolution of high brightness bunches. The technique involves the coupling of the electron beam to a high power laser in an undulator field, which is optimized to maximize the angular deviation of the bunch. The beam angular components are imaged on a distant screen yielding a sweep across angles in one dimension. The addition of an x-band deflecting cavity downstream of the undulator creates another sweep of the beam, in the perpendicular dimension. The temporal resolution of the bunch is dependent on the seed laser wavelength and the spatial resolution of the screen. Initial calculations show that for a CO2 laser (T~30fs) and a phosphor screen (~50micron spatial resolution), the longitudinal resolution is approximately l/200 of the laser wavelength, or ~150 attoseconds.

 
MOPE094 X-band Travelling Wave Deflector for Ultra-fast Beams Diagnostics 1206
 
  • L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh
    RadiaBeam, Santa Monica
  • D. Alesini
    INFN/LNF, Frascati (Roma)
  • J.B. Rosenzweig
    UCLA, Los Angeles, California
  • V. Yakimenko
    BNL, Upton, Long Island, New York
 
 

The quest for detailed information concerning ultra-fast beam configurations, phase spaces and high energy operation is a critical task in the world of linear colliders and X-ray FELs. Huge enhancements in diagnostic resolutions are represented by RF deflectors. In this scenario, Radiabeam Technologies has developed an X-band Travelling wave Deflector (XTD) in order to perform longitudinal characterization of the subpicosecond ultra-relativistic electron beams. The device is optimized to obtain a single digit femtosecond resolution using 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory; however, the design can be easily extended to be utilized for diagnostics of GeV-class beams. The XTD design fabrication and tuning results will be discussed, as well as installation and commissioning plans at ATF.


* J. England et al., "X-Band Dipole Mode Deflecting Cavity for the UCLA Neptune Beamline".
** D. Alesini, "RF deflector-based sub-ps beam diagnostics: application to FELs and advanced accelerators".

 
TUPEC021 SW/TW Hybrid Photoinjector and its Application to the Coherent THz Radiation 1758
 
  • A. Fukasawa, J.B. Rosenzweig, D. Schiller
    UCLA, Los Angeles, California
  • D. Alesini, L. Ficcadenti, B. Spataro
    INFN/LNF, Frascati (Roma)
  • L. Faillace, L. Palumbo
    Rome University La Sapienza, Roma
 
 

A unique SW/TW hybrid photoinjector are being developed under the collaboration of UCLA, LNF/INFN, and University of Rome. It can produce 240-fs (rms) bunch with 500 pC at 21 MeV. The bunch distribution has a strong spike (54 fs FWHM) and the peak current is over 2kA. As the bunch form factor at 1 THz is 0.43, it can produce coherent radiation at 1 THz. We are considering three types of way to generate it; coherent Cherenkov radiation (CCR), superradiant FEL, and coherent transition/edge radiation (CTR/CER). CCR used hollow dielectric with the outer surface metallic-coated. OOPIC simulation showed 21 MW of the peak power (5 mJ) at 1 THz. For FEL and CTR/CER simulation, QUINDI, which was written at UCLA to solve the Lienard-Wiechert potential, was used to calculate the radiation properties. In the contrast to CCR, their spectra were broad and their pulse lengths were short. They will be useful for fast pumping.

 
TUPE063 Generation of Optical Orbital Angular Momentum in a Free-electron Laser 2278
 
  • E. Hemsing, A. Marinelli, J.B. Rosenzweig
    UCLA, Los Angeles, California
 
 

A simple scheme to generate intense light with orbital angular momentum in an FEL is described. The light is generated from a helically pre-bunched beam created in an upstream modulator. The beam energy is tuned to maximize gain in the higher-order mode which reaches saturation well before the spontaneous modes driven by noise are amplified.

 
TUPE082 Advanced Beam Dynamics Experiments with the SPARC High Brightness Photoinjector 2311
 
  • M. Ferrario, D. Alesini, F. A. Anelli, M. Bellaveglia, M. Boscolo, L. Cacciotti, M. Castellano, E. Chiadroni, L. Cultrera, G. Di Pirro, L. Ficcadenti, D. Filippetto, S. Fioravanti, A. Gallo, G. Gatti, A. Mostacci, E. Pace, R.S. Sorchetti, C. Vaccarezza
    INFN/LNF, Frascati (Roma)
  • A. Bacci, V. Petrillo, A.R. Rossi, L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano
  • A. Cianchi, B. Marchetti
    INFN-Roma II, Roma
  • L. Giannessi, A. Petralia, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • O. Limaj
    University of Rome La Sapienza, Rome
  • M. Moreno, M. Serluca
    INFN-Roma, Roma
  • J.B. Rosenzweig
    UCLA, Los Angeles, California
  • H. Tomizawa
    JASRI/SPring-8, Hyogo-ken
  • C. Vicario
    PSI, Villigen
 
 

The primary goal of the SPARC project is the commissioning of the SASE FEL operating at 500 nm driven by a 150-200 MeV high brightness photoinjector. Additional experiments are foreseen also in the HHG Seeded configuration at 266, 160 and 114 nm. A second beam line hosting a THz source has been recently commissioned. The recent successful operation of the SPARC injector in the Velocity Bunching (VB) mode has opened new perspectives to conduct advanced beam dynamics experiments with ultra-short electron pulses able to extend the THz spectrum and to drive the FEL in the SASE Single Spike mode. Moreover a new technique called Laser Comb, able to generate a train of short pulses with high repetition rate, as the one required to drive coherent plasma wake field excitation, has been tested in the VB configuration. The energy/density modulation produced by an infrared laser pulse interacting with the electron beam near the cathode has been also investigated. In this paper we report the experimental results obtained so far and the comparison with simulations.

 
WEPE077 Permanent Magnet Quadrupole Final Focus System for the Muon Collider 3524
 
  • F.H. O'Shea, J.B. Rosenzweig
    UCLA, Los Angeles, California
  • G. Andonian
    RadiaBeam, Marina del Rey
 
 

One of the challenges of the proposed muon collider is the beam size at the interaction region. The current target for the beta function (beta-star) is 10mm for the 1.5TeV scenario with a beam emittance of 25mm-mrad. In this paper, we describe the design and development of a final focusing scheme that attempts to reach these parameters. The final focus scheme is based on the use of permanent magnet quadrupoles (PMQ) in a triplet configuration. Initial simulations show that the PMQs reach gradients as high as ~990T/m using Praseodymium based magnets in a Halbach style arrangement. Possible methods for tuning the PMQs at the interaction region, via temperature control and high-resolution movers, are also described.

 
THOAMH02 High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL 3605
 
  • J.B. Rosenzweig, G. Travish
    UCLA, Los Angeles, California
  • M.J. Hogan
    SLAC, Menlo Park, California
  • P. Muggli
    USC, Los Angeles, California
 
 

Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in ~33 cm DWA tubes. In the nearer term before FACET's commissioning, we are planning measurements at the BNL ATF, in which we drive ~50-200 MV/m fields with single pulses or pulse trains. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for high efficiency operatio with pulse trains.

 

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Slides

 
THPEA008 Experimental Characterization of the RF Gun Prototype for the SPARX-FEL Project 3688
 
  • L. Faillace, L. Palumbo
    Rome University La Sapienza, Roma
  • P. Frigola
    RadiaBeam, Marina del Rey
  • A. Fukasawa, B.D. O'Shea, J.B. Rosenzweig
    UCLA, Los Angeles, California
  • B. Spataro
    INFN/LNF, Frascati (Roma)
 
 

The quest for high brightness beams is a crucial key for the SPARX-FEL Project. In this paper, we present the design (including RF modeling, cooling, thermal and stress analyses as well as frequency detuning) of a single feed S-Band RF Gun capable of running near 500 Hz. An alternative design with dual feed has already been designed. Also, experimental results from the RF characterization of the prototype, including field measurements, are presented. The RF design follows the guidelines of the LCLS Gun, but the approach diverges significantly as far as the management of the cooling and mechanical stress is concerned. Finally, we examine the new proprietary approach of RadiaBeam Technologies for fabricating copper structures with intricate internal cooling geometries that may enable very high repetition rate.


* C.Limborg et al., "RF Design of the LCLS Gun".
** P. Frigola et al., "Development of solid freeform fabrication (SFF) for the production of RF Photoinjectors".

 
THPEA059 Ultra-high Gradient Compact S-band Linac for Laboratory and Industrial Applications 3807
 
  • L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh
    RadiaBeam, Marina del Rey
  • V.A. Dolgashev
    SLAC, Menlo Park, California
  • J.B. Rosenzweig
    UCLA, Los Angeles, California
 
 

There is growing demand from the industrial and research communities for high gradient, compact RF accelerating structures. The commonly used S-band SLAC-type structure has an operating gradient of only about 20 MV/m; while much higher operating gradients (up to 70 MV/m) have been recently achieved in X-band, as a consequence of the substantial efforts by the Next Linear Collider (NLC) collaboration to push the performance envelope of RF structures towards higher accelerating gradients. Currently however, high power X-band RF sources are not readily available for industrial applications. Therefore, RadiaBeam Technologies is developing a short, standing wave S-band structure which uses frequency scaled NLC design concepts to achieve up to a 50 MV/m operating gradient at 2856 MHz. The design and prototype commissioning plans are presented.

 
THPEC015 Breaking the Attosecond, Angstrom and TV/m Field Barriers with Ultra-fast Electron Beams 4080
 
  • J.B. Rosenzweig, G. Andonian, A. Fukasawa, E. Hemsing, G. Marcus, A. Marinelli, P. Musumeci, B.D. O'Shea, F.H. O'Shea, C. Pellegrini, D. Schiller, G. Travish
    UCLA, Los Angeles, California
  • P.H. Bucksbaum, M.J. Hogan, P. Krejcik
    SLAC, Menlo Park, California
  • M. Ferrario
    INFN/LNF, Frascati (Roma)
  • S.J. Full
    Penn State University, University Park, Pennsylvania
  • P. Muggli
    USC, Los Angeles, California
 
 

Recent initiatives at UCLA concerning ultra-short, GeV electron beam generation have been aimed at achieving sub-fs pulses capable of driving X-ray free-electron lasers (FELs) in single-spike mode. This uses of very low charge beams, which may allow existing FEL injectors to produce few-100 attosecond pulses, with very high brightness. Towards this end, recent experiments at the Stanford X-ray FEL (LCLS, first of its kind, built with essential UCLA leadership) have produced ~2 fs, 20 pC electron pulses. We discuss here extensions of this work, in which we seek to exploit the beam brightness in FELs, in tandem with new developments at UCLA in cryogenic undulator technology, to create compact accelerator/undulator systems that can lase below 0.15 Angstroms, or be used to permit 1.5 Angstrom operation at 4.5 GeV. In addition, we are now developing experiments which use the present LCLS fs pulses to excite plasma wakefields exceeding 1 TV/m, permitting a table-top TeV accelerator for frontier high energy physics applications.

 
THPD045 Fabrication of a Laser-based Microstructure for Particle Acceleration 4381
 
  • J. Zhou, J.C. McNeur, J.B. Rosenzweig, G. Travish
    UCLA, Los Angeles
  • R.B. Yoder
    Manhattanville College, Purchase, New York
 
 

The Micro-Accelerator Platform is an optical-wavelength microstructure for laser acceleration of particles, currently under development at UCLA. It is a slab-symmetric structure and can be constructed in layers using existing nanofabrication techniques. We present several possible fabrication techniques and preliminary experimental outcomes for manufacturing this structure.

 
THPD047 A Tapered Dielectric Structure for Laser Acceleration at Low Energy 4387
 
  • J.C. McNeur, R. Dusad, Z.B. Hoyer, J.B. Rosenzweig, G. Travish, N. Vartanian, J. Xu, J. Zhou
    UCLA, Los Angeles
  • E.R. Arab
    PBPL, Los Angeles
  • R.B. Yoder
    Manhattanville College, Purchase, New York
 
 

This paper extends the physics of the Micro-Accelerator Platform (MAP), which is in development as an optical structure for laser acceleration of relativistic electrons. The MAP is a resonant, optical-scale, slab-symmetric device that is fabricated from dielectric materials using layer-deposition techniques. For stand-alone applications, low-energy electrons (beta ~ 0.3) must be synchronously accelerated to relativistic speeds for injection into the MAP. Even lower energies are desired for other particle species (e.g. protons or muons). In this paper, we present design and simulation studies on a tapered geometry and associated coupling scheme that can produce synchronous acceleration at beta < 1 within a MAP-like structure.