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brightness

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MOPC023 ARC-EN-CIEL Beam Dynamics emittance, laser, gun, space-charge 115
 
  • A. Loulergue, M.-E. Couprie
    SOLEIL, Gif-sur-Yvette
  • C. Bruni
    LAL, Orsay
  ARC-EN-CIEL project is based on a CW 1.3 GHz superconducting linac accelerator delivering high charge, subpicosecond and low emittance electron bunches at high repetition rate. According to the electron energy, it provides tunable light source of high brightness in the VUV to soft X-ray wavelength domain. The project will evolve into three phases: first and second phases are based on high brightness single pass SC linac configuration with a low average current (few μA), while third phase comports recirculation loops to increase the average current (up to 100 mA). This paper deals with electron beam dynamics issues for the single pass configuration in the two first phases from the RF gun to undulators including magnetic compression stages. In the ERL configuration of the third phase, the accelerator scheme and focusing are investigated in order to take into account collective effects as Beam Break Up instability.  
 
MOPC071 Development of a High Brightness Photo-Injector for Light Source Research at NSRRC gun, laser, electron, emittance 229
 
  • W. K. Lau, J. H. Chen, C. S. Chou, G.-Y. Hsiung, K. T. Hsu, J.-Y. Hwang, A. P. Lee, C. C. Liang, G.-H. Luo, D.-J. Wang
    NSRRC, Hsinchu
  • C. H. Chen, N. Y. Huang, Y.-C. Huang, W. K. Luo
    NTHU, Hsinchu
  A laser driven photo-cathode rf gun system is being installed at NSRRC gun testsite for high brightness electron beam and light source research. The photo-cathode rf gun cavity geometry has been modified from the BNL 1.6-cell structure for 2998 MHz operation. A 798 nm Ti:Saphire laser seeded 3 mJ regenerative amplifier is employed to produce 300 microjoules UV pulses at 266 nm wavelength from a third harmonic generator crystal for emission of photo-electrons from the Cu-cathode in the rf gun. First operation of this system with gaussian laser pulses is scheduled in summer 2008. Future plan for flattop laser pulse operation will be discussed.  
 
TUPC027 Spatial Autocorrelation for Transverse Beam Quality Characterization laser, emittance, focusing, space-charge 1107
 
  • V. Fusco, M. Ferrario
    INFN/LNF, Frascati (Roma)
  • C. Ronsivalle
    ENEA C. R. Frascati, Frascati (Roma)
  Low emittance beams are required for high brightness beams applications. Contributions to emittance degradations come from electromagnetic fields’ non-linearities which can be reduced using a transversally and longitudinally uniform beam. For these reasons the evaluation of the beam quality is a very important task. Concerning the transverse analysis the spatial correlation parameter has been introduced: it gives an evaluation of how beam non-uniformity is distributed. The paper describes the spatial autocorrelation concept and applies it to the evaluation of a laser beam for high brightness beam applications. Moreover the paper shows the spatial autocorrelation evolution along a photo-injector as an additional tool for beam dynamics studies.  
 
TUPP086 Efficient 3D Space Charge Calculations by Self-adaptive Multigrid Methods Using the Chombo Framework space-charge, electron, vacuum, simulation 1730
 
  • C. R. Bahls, G. Pöplau, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock
  Current and future accelerator design requires efficient 3D space charge computations for high brightness bunches which should be as precise and fast as possible. One possible approach for space charge calculations is the particle-mesh-method, where the potential is calculated in the rest frame of the bunch by means of Poisson's equation. For an efficient solution of this elliptic PDE an appropriate adaptive discretization of the domain is required. Especially it has to take into account discontinuities in the distribution of the particles. The solution method we investigate in this paper is a self-adaptive multigrid method applying composite grids. To accomplish this, we use the library Chombo* which is being developed as a framework for adaptive multiresolution solvers for elliptic and hyperbolic partial differential equations.

*Developed and distributed by the Applied Numerical Algorithms Group
of Lawrence Berkeley National Lab., http://seesar.lbl.gov/ANAG/chombo/

 
 
TUPP103 The Performance of 3D Space Charge Models for High Brightness Electron Bunches space-charge, simulation, electron, cathode 1770
 
  • G. Pöplau, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock
  • K. Floettmann
    DESY, Hamburg
  Precise and fast 3D space charge calculations for high brightness, low emittance electron beams are of growing importance for the design of future accelerators and light sources. The program package Astra (A space charge tracking algorithm) has been successfully used in the design of linac and rf photo injector systems. The Astra suite originally developed by K. Flöttmann tracks macro particles through user defined external fields including the space charge field of the particle cloud. In this paper we investigate the performance of the 3D space charge models implemented in Astra. These are the FFT-Poisson solver with the integrated Green's function and the iterative Poisson solver based on the multigrid technique. The numerical tests consider the accuracy of the solvers for model bunches as well as the performance within a typical simulation for the XFEL.  
 
TUPP130 Development of 3D Dose Verification System for Scanned Ion Beam at HIMAC ion, background, target, heavy-ion 1830
 
  • N. Saotome, T. Furukawa, T. Inaniwa, T. Kanai, K. Noda, S. Sato
    NIRS, Chiba-shi
  A 3D dose imaging system has been developed for a project of a new cancer treatment with 3D pencil beam scanning at HIMAC. This system provides the dose measurements easily and rapidly. this system consists of a water tank, fluorescent screen and charge-coupled device, set at isocentor. The fluorescent screen is directly attached to the downstream side of water tank. One of great advantages of this system is to obtain 2D dose map at once, by correcting LET-dependent quenching. The procedure to verify 3D dose distribution is based on the 2D dose measurement of slice-by-slice under a water depth. We will present the measurement result of 3D dose distribution by the proposed method, and its comparison with that by the ionization chamber.  
 
WEOBG04 First Experimental Results from DEGAS, the Quantum Limited Brightness Electron Source laser, electron, controls, feedback 1918
 
  • M. S. Zolotorev, J. W. ONeill, F. Sannibale, W. Wan
    LBNL, Berkeley, California
  • E. D. Commins, A. S. Tremsin
    UCB, Berkeley, California
  The construction of DEGAS (DEGenerate Advanced Source), a proof of principle for a quantum limited brightness electron source, has been completed at the Lawrence Berkeley National Laboratory. The commissioning and the characterization of this source, designed to generate coherent low energy (10-100 eV) single electron "bunches" with brightness approaching the quantum limit at a repetition rate of few MHz, has been started. In this paper the first experimental results are described.  
slides icon Slides  
 
WEPC023 Ideas for a Future PEP Light Source undulator, emittance, photon, storage-ring 2031
 
  • R. O. Hettel, K. L.F. Bane, L. D. Bentson, K. J. Bertsche, S. M. Brennan, Y. Cai, A. Chao, S. DeBarger, V. A. Dolgashev, X. Huang, Z. Huang, D. Kharakh, Y. Nosochkov, T. Rabedeau, J. A. Safranek, J. Seeman, J. Stohr, G. V. Stupakov, S. G. Tantawi, L. Wang, M.-H. Wang, U. Wienands
    SLAC, Menlo Park, California
  • I. Lindau
    Stanford University, Stanford, Califormia
  • C. Pellegrini
    UCLA, Los Angeles, California
  With the termination of operation of the PEP-II storage rings for high energy physics at hand, and with the migration of accelerator operation at SLAC in general to photon science applications, a study of the potential conversion of the PEP-II to a future light source has been initiated. With a circumference of 2.2 km and the capability for high current operation, it is clear that operating a converted ring at medium energy (3-6 GeV) could offer very low emittance and an average brightness of order 1022, limited primarily by the power handling capacity of photon beam line optical components. Higher brightness in the soft X-ray regime might be reached with partial lasing in long undulators if the emittance is sufficiently low, and high peak brightness could be reached with seeded FEL emission. Advanced pulsed rf technology might be used to generate short bunches and fast switched polarization in soft X-ray rf undulators. An overview of the preliminary findings of the PEP Light Source study group will be presented, including lattice, X-ray source and beam line options.  
 
WEPC050 Future Plans for the Advanced Light Source lattice, emittance, injection, synchrotron 2103
 
  • D. Robin, H. Nishimura, G. J. Portmann, F. Sannibale, C. Steier
    LBNL, Berkeley, California
  The Advanced Light Source is now in its 15th year of operation. The facility has managed to continue to improve through continual upgrades to both the capabilities and capacities. Studies have shown that there is still plenty of room for improvements. Here we present plans to provide sustantial relevant improvements with modest cost.  
 
WEPC052 Achieving Stability Requirements for Nanoprobe and Long Beam Lines at NSLS II. A Comprehensive Study site, ground-motion, extraction, acceleration 2109
 
  • N. Simos, L. Berman, A. J. Broadbent, K. Evans-Lutterodt, M. Fallier, J. Hill
    BNL, Upton, Long Island, New York
  Driven by beam stability requirements at the NSLS II synchrotron a comprehensive study has been launched seeking to provide assurances that nanometer level stability at critical x-ray beam-lines is achievable, given the vibration environment at the selected site. Through this effort which represents the integration of an array of field measurements and a state-of-the-art model of wave propagation, the stability of special NSLS II beam-lines that push the envelope of beam size is quantified. In particular, the effects of ground vibration at the NSLS II site are studied both deterministically and stochastically to account for the stochastic nature of the disturbances arriving at the site and interact with the ring and the experimental lines. Validated numerical models are utilized in an effort to guide the design of sensitive lines. The objective is to both minimize vibration amplification as well establish a relative stability envelope between the beam extraction and imaging locations of the sensitive NSLS II beam-lines.