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MOYCH03 Superconducting RF Cavities for Synchrotron Light Sources synchrotron, extraction, impedance, hadron 21
 
  • P. Marchand
    SOLEIL, Gif-sur-Yvette
  Superconducting (sc) RF systems are already operational or planned in several third generation synchrotron light sources. In these machines, which require relatively low RF accelerating voltage and high beam loading, the advantage of using the sc technology essentially resides in the fact that one can achieve an efficient damping of the cavity Higher Order Modes (HOM) while still maintaining a high fundamental shunt impedance. The strong HOM damping practically is realised following two approaches : a) use of absorber material, located inside the cavity tube cut-off, through which the HOM propagate and then are damped (Cornell/KEK designs); b) two-cell cavity with coaxial HOM dampers located on the tube connecting the two cells (SOLEIL design). Third harmonic idle sc cavities (1.5 GHz) of the SOLEIL type are already operational in the Swiss Light Source and ELETTRA. The main RF system (500 MHz) of these machines consist of normal conducting cavities and the purpose of the third harmonic sc system is to lengthen the bunches in order to improve the beam lifetime and stability (additional Landau damping). Recently, several third generation synchrotron light sources have also planned to use sc cavities as main accelerating RF systems. The operational conditions of the existing systems as well as the status of the planned ones are reported here.  
Video of talk
Transparencies
 
MOZCH01 Technologies for Electron-positron Linear Colliders collider, synchrotron, extraction, impedance 26
 
  • S.D. Holmes
    Fermilab, Batavia, Illinois
  High energy electron-positron Linear Collider designs based on room temperature and superconducting technologies have been developed and are currently under consideration by the International Technology Recommendation Panel. This paper will review the requirements and state of development of technologies required to support a linear collider meeting the performance goals outlined by the world high energy physics community. In addition it will summarize the cold/warm comparative study completed in the U.S. with particular emphasis on unique aspects related to availability and risk analysis.  
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Transparencies
 
MOZCH02 Start to End Simulations of Low Emittance Tuning and Stabilization simulation, collider, emittance, synchrotron 31
 
  • P. Tenenbaum, A. Seryi, M. Woodley
    SLAC, Menlo Park, California
  • D. Schulte
    CERN, Geneva
  • N.J. Walker
    DESY, Hamburg
  • G.R. White
    Queen Mary University of London, London
  The principal beam dynamics challenge to the subsystems between the damping ring and the collision point of future linear colliders is expected to be the tuning and stabilization required to preserve the transverse emittance and to collide nanometer-scale beams. Recent efforts have focused on realistically modelling the operation and tuning of this region, dubbed the Low Emittance Transport (LET). We report on the development of simulation codes which permit integrated simulation of this complex region, and on early results of these simulations. Future directions of LET simulation are also revealed.  
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Transparencies
 
MOOCH01 Beam Based Alignment at the KEK-ATF Damping Ring simulation, alignment, emittance, synchrotron 36
 
  • M. Woodley, J. Nelson, M.C. Ross, J.L. Turner
    SLAC, Menlo Park, California
  • K. Kubo
    KEK, Ibaraki
  • A. Wolski
    LBNL/AFR, Berkeley, California
  The damping rings for a future linear collider will have demanding alignment and stability requirements in order to achieve the low vertical emittance necessary for high luminosity. The Accelerator Test Facility (ATF) at KEK has successfully demonstrated the <5 pm vertical emittance specified for the GLC/NLC Main Damping Rings [*]. One contribution to this accomplishment has been the use of Beam Based Alignment (BBA) techniques. The mode of operation of the ATF presents particular challenges for BBA, and we describe here how we have deduced the offsets of the BPMs with respect to the quadrupoles. We also discuss a technique that allows for direct measurements of the beam-to-quad offsets.

* "Extremely Low Vertical-Emittance Beam in the Accelerator Test Facility at KEK", K. Kubo, et al., Phys.Rev.Lett.88:194801,2002

 
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Transparencies
 
MOOCH03 Status of a Linac RF Unit Demonstration for the NLC/GLC X-band Linear Collider simulation, acceleration, alignment, emittance 42
 
  • D.C. Schultz, C. Adolphsen, D.L. Burke, J. Chan, S. Doebert, V.A. Dolgashev, J.C. Frisch, R.K. Jobe, D.J. McCormick, C.D. Nantista, J. Nelson, M.C. Ross, T.J. Smith, S.G. Tantawi
    SLAC, Menlo Park, California
  • D.P. Atkinson
    LLNL, Livermore, California
  • Y.H. Chin, S. Kazakov, A. Lounine, T. Okugi, N. Toge
    KEK, Ibaraki
  Designs for a future TeV scale electron-positron X-band linear collider (NLC/GLC) require main linac units which produce and deliver 450 MW of rf power at 11.424 GHz to eight 60 cm accelerator structures. The design of this rf unit includes a SLED-II pulse compression system with a gain of approximately three at a compression ratio of four, followed by an overmoded transmission and distribution system. We have designed, constructed, and operated such a system as part of the 8-Pack project at SLAC. Four 50 MW X-band klystrons, running off a common 400 kV solid-state modulator, drive a dual-moded SLED-II pulse compression system. The compressed power is delivered to structures in the NLCTA beamline. Four 60 cm accelerator structures are currently installed and powered, with four additional structures and associated high power components available for installation late in 2004. We describe the layout of our system and the various high-power components which comprise it. We also present preliminary data on the processing and initial high-power operation of this system.  
Video of talk
Transparencies
 
MOPKF003 Design of 2 T Wiggler Vacuum Chamber for the LNLS Storage Ring acceleration, alignment, emittance, simulation 300
 
  • M.J. Ferreira, R.O. Ferraz, H.G. Filho, M.B. Silva
    LNLS, Campinas
  A 2 T wiggler with 2.8 m long and a gap of 22 mm will be installed at LNLS storage ring. The main requirements of the chamber design are short conditioning time and low mechanical deformation. Two different designs in stainless steel are proposed for the prototypes, an elliptical tube and a machined sheet. A pressure profile simulation with and without a NEG coating were made for evaluating the life-time influence and the time necessary for conditioning. A simulation with finite element of mechanical deformation for both case show equivalent results. The first prototype was made with the elliptical tube and a NEG coating deposition will be made at ESRF. The second prototype with machined parts is under construction and will be TIG welded. Descriptions of mounting structure for the prototype are show and the evaluation the dimension tolerance of the chambers.  
 
MOPKF004 Magnet Sorting Algorithm Applied to the LNLS EPU acceleration, undulator, alignment, emittance 303
 
  • X.R. Resende, R.M. Dias
    LNLS, Campinas
  The Brazilian Synchrotron Light Laboratory is about to begin the construction of the first Undulator for its 1.37 GeV electron storage ring. This device will be of the EPU type with a period of 50 milimeters and 22 milimeters minimum magnetic gap. In this work we report on the sorting algorithm applied in the construction of a 10-period undulator prototype.  
 
MOPKF005 Preliminary Results on a Low Emittance Gun Based on Field Emission emittance, electron, undulator, alignment 306
 
  • R. Ganter, A.E. Candel, M. Dehler, G.J. Gobrecht, C. Gough, S.C. Leemann, K.L. Li, M. Paraliev, M. Pedrozzi, J.-Y. Raguin, L. Rivkin, V. Schlott, L. Schulz, A. Streun, A. Wrulich
    PSI, Villigen
  The development of a new electron gun with the lowest possible emittance would help reducing the total length and cost of a free electron laser. Recent progresses in vacuum nanoelectronics make field emitter arrays (FEAs) an attractive technology to explore for high brightness sources. Indeed, several thousands of microscopic tips can be deposited on a 1 mm diameter area. Electrons are then extracted by a first grid layer close to tip apex and focused by a second grid layer one micrometer above the tip apex. The typical aperture diameter of this focusing layer is also in the range of one micrometer. The big challenge with FEA, is to achieve good emission homogeneity, we hope to achieve this with diverse conditioning techniques. However if we can achieve a low emittance with FEAs another challenge will be to preserve the emittance during the beam acceleration.  
 
MOPKF008 The BESSY Soft X-ray FEL User Facility emittance, electron, undulator, alignment 312
 
  • D. Krämer
    BESSY GmbH, Berlin
  A FEL User Facility for the VUV to soft X-ray spectral range is planned at the BESSY site based on a cascaded HGHG-FEL scheme. Simultaneous operation of 3 - later 5 - FELs fed by a superconducting 2.3 GeV CW linac generates most flexible pulse structures for experiments, while the seeding scheme utilizing Ti:Sa fs-lasers results in ultrashort reproducible circular polarized FEL pulses on a shot to shot basis at a pulse-duration < 20 fs. Peak brilliances in the 1·1031 ph/(s mm2 mrad2 0.1% bw)-regime are feasible. All necessary hardware for the FEL is within existing technology. Future upgrade options, e.g. a superconducting photoinjector, seeding with short wavelength HHG lasers of about 1 fs pulse duration have been considered. A status on the design aspects is given.  
 
MOPKF010 The Output Performance of the BESSY Multi-stage HGHG-FEL gun, alignment, brilliance, photon 318
 
  • A. Meseck, M. Abo-Bakr, B.C. Kuske
    BESSY GmbH, Berlin
  The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generatio(HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral range(0.02 keV - 1. keV). A photoinjector and a superconducting 2.3GeV CW linac will feed three independent HGHG-FEL-lines. As the efficiency of the interaction between the radiation and the electron beam is higher in a helical undulator, one would tend to prefer such a device for the HGHG scheme. Also a higher K-value of the modulators seems to be advantageous. This is not necessarily the case. We present simulation studies for the BESSY-HGHG-FELs and discuss the output performance for ‘‘helical stages'' and increased K value of the modulators.  
 
MOPKF011 Output Variability of the BESSY Soft X-ray FEL gun, alignment, brilliance, photon 321
 
  • A. Meseck, M. Abo-Bakr, B.C. Kuske
    BESSY GmbH, Berlin
  The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generation HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral rang(0.02 keV - 1 keV). A photoinjector and a superconducting $2.3\,GeV$ CW linac will feed three independent HGHG-FEL-lines. Depending on the optimisation criteria, it is possible to obtain either maximum output power or pure spectrum from the same HGHG-line. We present simulation studies for the BESSY-HGHG-FELs and discuss the possible variability of the output performance.  
 
MOPKF012 A 7T Multipole Wiggler in BESSY II: Implementation and Commissioning Results gun, wiggler, radiation, alignment 324
 
  • E. Weihreter, J. Feikes, P. Kuske, R. Müller, G. Wustefeld
    BESSY GmbH, Berlin
  • D. Berger
    HMI, Berlin
  • N.A. Mezentsev, V. Shkaruba
    BINP SB RAS, Novosibirsk
  To generate hard X-ray beams for residual stress analysis and for magnetic scattering with the BESSY II SR source, a 7T wiggler with 17 poles has been implemented. Several problems had to be solved. Wake fields induced by smaller steps in the geometry of the radiation shield inside the beam chamber led to intolerable LHe consumption, which have been analysed numerically and then cured by improving the shield geometry. Much of the routine operation procedures are influenced by the unusually high radiation power level of max. 55 kW. For system protection an interlock system dumps the electron beam automatically in case of relevant error events. This wiggler is by far the strongest perturbation of the linear beam optics, breaking seriously the symmetry of the ring. Beam optical parameters including tune shift and beta beat have been measured to quantify these perturbations and develop efficient cures to limit the negative effects on beam lifetime and dynamic aperture. So far the wiggler is operated at 2.8 T and max. currents up to 250 mA in normal user shifts.  
 
MOPKF013 The Influence of the Main Coupler Field on the Transverse Emittance of a Superconducting RF Gun wiggler, radiation, gun, alignment 327
 
  • D. Janssen
    FZR, Dresden
  • M. Dohlus
    DESY, Hamburg
  For the Rossendorf superconducting RF gun project the influence of the additional RF field, created in the cavity by the RF power flow at the main coupler, is discussed. One end of the gun cavity is occupied by the cathode insert, so all flanges are concentrated on the other end. In the "flange plane" of the cavity two HOM coupler, the pic up and the main coupler are located. If we normalize the RF field in the cavity by the condition Eacc = 25MV/m and assume a beam power of 10kW (CW mode), we obtain an quality factor Qext = 2.2*10**7. A three dimensional field calculation using the MAFIA code, gives the field perturbation near the main coupler. Tracking calculation with ASTRA show,that this perturbation increases the transversel emittance between 1 and 4%, nearly independent from the bunch charge. This result shows, that for average beam powers in the vicinity of 10kW effects, connected with the assymetric input of RF power can be neglected.  
 
MOPKF014 Emittance Compensation of a Superconducting RF Photoelectron Gun by a Magnetic RF Field wiggler, radiation, gun, alignment 330
 
  • D. Janssen
    FZR, Dresden
  • V. Volkov
    BINP SB RAS, Novosibirsk
  For compensation of transverse emittance in normal conducting RF photoelectron guns a static magnetic field is applied. In superconducting RF guns the application of a static magnetic field is impossible. Therefore we put instead of a static field a magnetic RF field (TE - mode) together with the corresponding accelerating mode into the superconducting cavity of the RF gun. For a 3 _ cell cavity of the superconducting gun with frequencies f = 1.3GHz for the accelerating mode and f = 3.9 GHz for the magnetic mode and a bunch charge of 1 nC a transversal emittance of 0.5 mm mrad has been obtained. In this case the maximal field strength on the axis were Ez = 50 MV/m for the accelerating mode and Bz = 0.34 T for the magnetic mode.(This corresponds to Bs(max) = 0.22T on the surface of the cavity). Possibilities for the technical realization (input of RF power for the TE mode, tuning of two frequencies in one cavity, phase stability) are discussed.  
 
MOPKF015 A Superconducting Photo-Injector with 3+1/2- Cell Cavity for the ELBE Linac wiggler, radiation, gun, alignment 333
 
  • J. Teichert, H. Buettig, P. Evtushenko, D. Janssen, U. Lehnert, P. Michel, Ch. Schneider
    FZR, Dresden
  • W.-D. Lehmann
    IfE, Dresden
  • J. Stephan
    IKST, Drsden
  • V. Volkov
    BINP SB RAS, Novosibirsk
  • I. Will
    MBI, Berlin
  After successful tests of an SRF gun with a superconducting half-cell cavity [*], a new SRF photo-injector for CW operation at the ELBE linac has been designed. In this report the design layout of the SRF photo-injector, the parameters of the superconducting cavity and the expected electron beam parameters are presented. The SRF gun has a 31/2-cell niobium cavity working at 1.3 MHz and will be operated at 2 K. The three full cells have TESLA-like shapes. In the half-cell the photocathode is situated which will be cooled by liquid nitrogen.

* D. Janssen et. al., First operation of a superconducting RF-gun, Nucl. Instr. and Meth. A507(2003)314

 
 
MOPKF016 S2E Simulations on Jitter for European XFEL Project wiggler, radiation, gun, alignment 336
 
  • Y. Kim, Y. Kim, D. Son
    CHEP, Daegu
  • K. Floettmann, T. Limberg
    DESY, Hamburg
  In order to generate stable 0.1 nm wavelength SASE source at the European X-ray laser project XFEL, we should supply high quality electron beams with constant beam characteristics to a 200 m long undulator. Generally, beam parameters such as peak current and energy spread are significantly dependent on jitter or error in RF phase and RF amplitude of superconducting accelerating modules, and magnetic field error of bunch compressors. In this paper, we describe the start-to-end simulations from the cathode to the end of linac to determine the jitter and error tolerances for the European XFEL project.  
 
MOPKF017 New Simulations on Microbunching Instability at TTF2 wiggler, gun, alignment, emittance 339
 
  • Y. Kim, Y. Kim, D. Son
    CHEP, Daegu
  • K. Floettmann
    DESY, Hamburg
  Microbunching instability in the FEL driver linac can be induced by collective self-fields such as longitudinal space charge, coherent synchrotron radiation, and geometric wakefields. In this paper, we describe the first start-to-end simulations including all important collective self-fields from the cathode to the end of TTF2 linac with 1.5 million macroparticles.  
 
MOPKF018 Injector and Bunch Compressor for the European XFEL Project wiggler, gun, alignment, linac 342
 
  • Y. Kim, Y. Kim, D. Son
    CHEP, Daegu
  • M. Dohlus, K. Floettmann, T. Limberg
    DESY, Hamburg
  For the proper operation of European XFEL project, we should supply high quality electron beams with low emittance, short bunch length, and low energy spread to a 200 m long undulator. In this paper, we describe the optimization and design concepts of the XFEL injector and bunch compressors to control the beam parameter dilution due to the microbunching instability and CSR.  
 
MOPKF020 Proposal for a Sub-100 fs Electron Bunch Arrival-time Monitor for the VUV-FEL at DESY laser, wiggler, electron, gun 345
 
  • H. Schlarb, S. Düsterer, J. Feldhaus, J. Hauschildt, R. Ischebeck, K. Ludwig, B. Schmidt, P. Schmüser, S. Simrock, B. Steffen, F. Van den Berghe, A. Winter
    DESY, Hamburg
  • P.H. Bucksbaum, A. Cavalieri, D. Fritz, S. Lee, D. Reis
    Michigan University, Ann Arbor, Michigan
  For pump-probe experiments at the VUV-Free Electron Laser at DESY, an external optical laser system will be installed, capable of delivering ultra-short pulses of high intensity. The laser pulses with a center wavelength of 800 nm are synchronized with the VUV-FEL beam which covers the wavelength range between 6 nm and 80 nm. The expected pulse durations are typically 100 fs FWHM or below. For high-resolution pump-probe experiments a precise knowledge of the time difference between both pulses is mandatory. In this paper we describe the layout and the design of a high-precision electron bunch arrival time monitor based on an electro-optic technique. We present the numerical results of simulations that include: the laser propagation in a specifically designed demanding optical system, the laser transport through a 150 m long optical fibre, the electro-optically induced effect in different types of crystals and for different electron bunch shapes as well as the effects of wake fields on the co-propagating electric-fields and their impact on the observable signals.  
 
MOPKF021 Properties of Cathodes Used in the Photoinjector RF Gun at the DESY VUV-FEL laser, wiggler, electron, alignment 348
 
  • S. Schreiber
    DESY, Hamburg
  • J.H. Han
    DESY Zeuthen, Zeuthen
  • P. Michelato, L. Monaco, D. Sertore
    INFN/LASA, Segrate (MI)
  The new injector of the DESY VUV-FEL is being commissioned in spring 2004. Several cathodes have been tested in the photoinjector RF Gun. We report on quantum efficiency, dark current, and the overall appearance of the cathodes after their use.  
 
MOPKF022 Commissioning of the VUV-FEL Injector at TTF laser, wiggler, electron, alignment 351
 
  • S. Schreiber
    DESY, Hamburg
  The VUV-FEL at the TESLA Test Facility (TTF) at DESY is being upgraded to an FEL user facility serving high brilliance beams in the wavelength range from the VUV to soft X-rays. The photoinjector has been redesigned to meet the more demanding beam parameters in terms of transverse emittance, peak current, and energy spread. The first phase of the injector upgrade has been finished in spring 2004. We report on its commissioning, including first measurements of beam parameters.  
 
MOPKF025 Planar and Planar Helical Superconductive Undulators for Storage Rings, State of the Art laser, wiggler, electron, alignment 354
 
  • R. Rossmanith, A. Bernhard, B.K. Kostka
    FZK-ISS-ANKA, Karlsruhe
  • D. Dölling, A. Hobl, D. Krischel, S. Kubsky
    ACCEL, Bergisch Gladbach
  • U. Schindler, E. Steffens
    Erlangen University, Erlangen
  • T. Schneider
    FZ Karlsruhe, Karlsruhe
  Planar superconductive undulators for low beam currents were successfully tested in the past. In a next step devices suitable for small gaps in storage rings are in preparation. The tests will clarify experimentally the heat load generated by the beam in the cold bore and will allow to optimize the control system of such devices. In addition, the layout of the next generation of planar superconductive undulators with electrically variable polarization direction are introduced in this paper.  
 
MOPKF026 Conditioning and High Power Test of the RF Guns at PITZ laser, wiggler, gun, alignment 357
 
  • J.H. Han, K. Abrahamyan, J. Bähr, H.-J. Grabosch, M. Krasilnikov, D. Lipka, V. Miltchev, A. Oppelt, B. Petrosyan, D. Pose, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • I. Bohnet, J.-P. Carneiro, K. Floettmann, S. Schreiber
    DESY, Hamburg
  • M.V. Hartrott, R. Richter
    BESSY GmbH, Berlin
  • P. Michelato, L. Monaco, D. Sertore
    INFN/LASA, Segrate (MI)
  This paper describes the recent results of conditioning and high power tests of the photocathode RF guns at the Photo Injector Test Facility at DESY Zeuthen (PITZ). For successful operation of high gain SASE FELs, high phase space density of the electron beam is required. A high gradient in the gun has to be applied to improve the quality of the space charge dominated beams. In addition, long RF pulses and high repetition rate should be achieved to provide a high average power of FEL radiation. The first PITZ RF gun has been successfully tested at a mean power of 27 kW (900μseconds, 10 Hz, and 3 MW) and has been installed at the VUV-FEL at DESY Hamburg. Another RF gun has been installed at PITZ in January 2004 and is being conditioned for high power tests. The dark current behavior for various cathodes and for all operating schemes is also presented.  
 
MOPKF027 Optimizing the PITZ Electron Source for the VUV-FEL electron, wiggler, alignment, linac 360
 
  • M. Krasilnikov, J. Bähr, U. Gensch, H.-J. Grabosch, J.H. Han, D. Lipka, V. Miltchev, A. Oppelt, B. Petrosyan, D. Pose, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • K. Abrahamyan
    YerPhI, Yerevan
  • W. Ackermann, R. Cee, W.F.O. Müller, S. Setzer, T. Weiland
    TEMF, Darmstadt
  • G. Asova, G. Dimitrov, I. Tsakov
    INRNE, Sofia
  • I. Bohnet, J.-P. Carneiro, K. Floettmann, S. Riemann, S. Schreiber
    DESY, Hamburg
  • M.V. Hartrott, E. Jaeschke, D. Krämer, R. Richter
    BESSY GmbH, Berlin
  • P. Michelato, L. Monaco, C. Pagani, D. Sertore
    INFN/LASA, Segrate (MI)
  • J. Rossbach
    Uni HH, Hamburg
  • W. Sandner, I. Will
    MBI, Berlin
  The goal of the Photo Injector Test Facility at DESY Zeuthen (PITZ) is to test and optimize electron sources for Free Electron Lasers and future linear colliders. At the end of 2003 the first stage of PITZ (PITZ1) has been successfully completed, resulting in the installation of the PITZ RF gun at the Vacuum Ultra Violet - Free Electron Laser (VUV-FEL) at DESY Hamburg. The main results achieved during the PITZ1 extensive measurement program are discussed in this paper. A minimum normalized beam emittance of about 1.5 pi mm mrad for 1 nC electron bunch charge has been reached by optimizing numerous photo injector parameters, e.g. longitudinal and transverse profiles of the photocathode laser, RF phase, main and bucking solenoid current. The second stage of PITZ (PITZ2), being a large extension of the facility and its research program, has started now. Recent progress on the PITZ2 developments will be reported as well.  
 
MOPKF029 Seeding High Gain Harmonic Generation with Laser Harmonics produced in Gases wiggler, alignment, linac, laser 363
 
  • G. Lambert, B. Carré, M.-E. Couprie, D. Garzella
    CEA/Saclay, Gif-sur-Yvette
  • A. Doria, L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma)
  • T. Hara, H. Kitamura, T. Shintake
    RIKEN Spring-8 Harima, Hyogo
  Free electron lasers employing High Gain Harmonic Generation (HGHG) schemes are very promising coherent light sources for the soft X-ray regime. They offer both transverse and longitudinal coherence, inversely to Self Amplified Spontaneous Emission schemes, where the longitudinal coherence is limited. We propose here to seed HGHG with high harmonics produced by a Ti:Sa femtosecond laser focused on a gas jet, tuneable in the 100-10 nm spectral region. Specifities concerning the implementation of this particular laser source as a seed for HGHG are investigated. Theoretical ad numerical calculations (using PERSEO in particular) are given, for the cases of the SCSS and ARC-EN-CIEL projects.  
 
MOPKF030 "ARC-EN-CIEL" a Proposal for a 4th Generation Light Source in France wiggler, alignment, laser, photon 366
 
  • M.-E. Couprie, D. Garzella, B. Gilquin, P. Monot, L. Nahon
    CEA/DSM, Gif-sur-Yvette
  • O.V. Chubar, A. Loulergue
    SOLEIL, Gif-sur-Yvette
  • M. Desmons, M. Jablonka, F. Meot, A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • J.-R. Marquès
    LULI, Palaiseaux
  • J.-M. Ortega
    LURE, Orsay
  • A. Rousse
    LOA, Palaiseau
  An accelerator based 4th generation source is proposed to provide the user community with coherent femtosecond light pulses in the UV to X ray range. The project is based on a CW 700 MeV superconducting linac delivering high charge, subpicosecond, low emittance electron bunches with high repetition rate. This facility allows for testing High Gain Harmonic Generation seeded with high harmonics in gases, as well as the standard SASE mode, covering a spectral range down to 0.8 nm and 5 nm respectively. In addition, two beam loops are foreseen to increase the beam current in using the energy recovery technique. They will accommodate undulators for the production of femtosecond synchrotron radiation in the IR, VUV and X ray ranges together with a FEL oscillator in the 10 nm range.  
 
MOPKF031 SOLEIL Insertion Devices: The Progress Report wiggler, insertion, vacuum, radiation 369
 
  • O.V. Chubar, C. Benabderrahmane, A. Dael, M.-P. Level, O. Marcouillé, M. Massal
    SOLEIL, Gif-sur-Yvette
  The French national synchrotron radiation source SOLEIL is planned to start operation in 2006 with several different insertion devices installed in the storage ring either from "day one" or within the first year. The list of high-priority insertion devices includes: 3 planar hybrid in-vacuum undulators with the period of 20 mm; 3 Apple-II type PPM undulators with the period of 80 mm; 3 electromagnet elliptical undulators with the period of 256 mm, and a 640 mm period elliptical electromagnet undulator offering advanced possibilities for fine-tuning of polarization states of the emitted radiation. The emission of all these undulators is covering wide spectral range extending from hard X-rays to UV. Pre-design of the IDs was done by SOLEIL. The construction will be done by industrial companies and institutions with production capabilities. Magnetic assembly of the Apple-II and in-vacuum undulators is planned to be done in collaboration with ELETTRA and ESRF. The final magnetic measurements of all the IDs will be made in the SOLEIL magnetic measurements laboratory. The paper will present peculiarities of the magnetic design, calculated maximum-flux spectra and associated heat load in various modes of operation.  
 
MOPKF032 Status of the ESRF Insertion Devices undulator, wiggler, radiation, alignment 372
 
  • J. Chavanne, C. Penel, B. Plan, F. Revol
    ESRF, Grenoble
  The ESRF insertion devices are the object of a continuous refurbishment in order to follow the changing needs of the beamlines and increase their performances. The successful development of the narrow aperture aluminum chambers pumped by non evaporable getter has resulted in the reduction of the minimum gap from 16 mm to 11 mm . A new set of undulator magnetic assemblies with shorter magnetic periods are being prepared that make use of the lower gap. .A prototype of a new type of revolver undulator support has been completed and successfully tested. Such a structure allows the beamline user to switch between two different undulator periods in less than a minute. Three additional devices will be constructed in 2004. Three new in-vacuum undulators have been installed on the ring. One of them is based on an hybrid magnetic structure and achieves a peak field 20% higher than a pure permanent magnet undulator of identical period. Their main magnetic measurements results and interactions with the stored beam are presented.  
 
MOPKF035 Stabilization of the Pulsed Regimes on Storage Ring Free Electron Laser: The Cases of Super-ACO and Elettra injection, booster, wiggler, electron 381
 
  • C. Bruni, D. Garzella, G. Lambert, G.L. Orlandi
    LURE, Orsay
  • E. Allaria, R. Meucci
    INOA, Firenze
  • S. Bielawski
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex
  • M.-E. Couprie
    CEA/DSM, Gif-sur-Yvette
  • M. Danailov, G. De Ninno, B. Diviacco, M. Trovò
    ELETTRA, Basovizza, Trieste
  • D. Fanelli
    KTH/NADA, Stockholm
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma)
  In a Storage Ring Free Electron Laser (SRFEL) a relativistic electron beam interacts with the magnetostatic periodic field of an undulator, thus emitting synchrotron radiation. The light is stored in an optical cavity and amplified during successive turns of the particles in the ring. The laser intensity may appear as a "continuous wave (cw)" or show a stable pulsed behaviour depending on the value of the temporal detuning, i.e. the difference between the electron beam revolution period and the round trip of the photons in the cavity. It was recently shown, that the loss of stability in a SRFEL occurs through an Hopf bifurcation [*]. This observation opens up the perspective of introducing a derivative self-controlled feedback to suppress locally the bifurcation and enlarge the region of stable signal. A feedback of this type has been implemented on Super-ACO and shown to produce a significant and reproducible extension of the stable "cw" region. We review here these results and discuss new experiments performed on the Super-ACO and ELETTRA SRFELs.

* G. De Ninno and D. Fanelli, Phys. Rev. Lett. in press; M.E. Couprie et al. Nucl. Instrum.and Meth. A., in press

 
 
MOPKF039 The ELETTRA Superconducting Wiggler injection, booster, linac, vacuum 390
 
  • L. Tosi, C. Knapic, D. Zangrando
    ELETTRA, Basovizza, Trieste
  A 3.5 Tesla 64 mm period superconducting wiggler has been installed in the ELETTRA storage ring as a photon source for a future X-ray diffraction beamline. After several technological upgrades, a series of measurements were carried out to characterize the device and its effects on the electron beam, such as optics distortion and dynamic aperture. A description of the upgrades and measurements are presented.  
 
MOPKF043 An Ultra-high Brightness, High Duty Factor, Superconducting RF Photoinjector injection, booster, vacuum, alignment 402
 
  • M. Ferrario
    INFN/LNF, Frascati (Roma)
  • J. Rosenzweig
    UCLA, Los Angeles, California
  • J. Sekutowicz
    DESY, Hamburg
  Recent advances in superconducting rf technology, and an improved understanding of rf photoinjector design optimization make if possible to propose a specific design for a superconducting rf gun which can simultaneously produce both ultra-high peak brightness, and high average current. Such a device may prove to be a critical component of next generation x-ray sources such as self-amplified spontaneous emission free-electron lasers (SASE FEL) and energy recovery linac (ERL) based systems. The design presented is scaled from the present state-of-the-art normal conducting rf photoinjector that has been studied in the context of the LCLS SASE FEL. Issues specific to the superconducing rf photoinjector, such as accelerating gradient limit, rf cavity design, and compatibility with magnetic focusing and laser excitation of a photocathode, are discussed.  
 
MOPKF044 Wake Fields Effects in the Photoinjector of the SPARC Project injection, booster, vacuum, alignment 405
 
  • V. Fusco, M. Ferrario, B. Spataro
    INFN/LNF, Frascati (Roma)
  • M.  Migliorati, L. Palumbo
    Rome University La Sapienza, Roma
  When a bunch travels off axis across structures whose shape is not uniform, such as RF cavity or bellows, generates longitudinal and transverse wake fields. In addition transverse time dependent fields (like transverse RF components and wake fields ) may induce correlated slice centroids displacement, so that each slice centroid motion become affected also by space charge forces generated by the next slices. An evaluation of the emittance degradation and induced energy spread in the SPARC injector is performed with an improved version of the code Homdyn and the results are discussed. A comparison with other codes (ABCI, PARMELA 3D) to validate our model is also presented.  
 
MOPKF045 Cesium Telluride and Metals Photoelectron Thermal Emittance Measurements Using a Time-of-flight Spectrometer injection, booster, emittance, vacuum 408
 
  • D. Sertore, D. Favia, P. Michelato, L. Monaco, P. Pierini
    INFN/LASA, Segrate (MI)
  The thermal emittance of photoemitted electrons in an RF gun is a crucial parameter for short wavelength FELs and future high luminosity electron colliders. An estimate of the thermal emittance of semiconductor and metal samples, commonly used as photocathodes, has been assessed using a Time-Of-Flight spectrometer. In this paper we present the analysis, based on angle resolved photoemission measurements, of both the cesium telluride (Cs2Te) photocathode films as used at the TESLA Test Facility, and polycrystalline metals. These latter measurements, at different laser wavelengths, are used to validate both our experimental apparatus and the thermal emittance reconstruction technique developed.  
 
MOPKF086 Modifications of the LCLS Photoinjector Beamline lepton, wiggler, undulator, cathode 521
 
  • C. Limborg-Deprey, D. Dowell, S.M. Gierman
    SLAC, Menlo Park, California
  The LCLS Photoinjector beamline is now in the Design and Engineering stage. The fabrication and installation of this beamline is scheduled for the summer 2006. The Photoinjector will deliver 10 ps long electron bunches of 1nC with a normalized transverse emittance of less than 1 mm.mrad for 80% of the slices constituting the core of the bunch at 135 MeV. In this paper, we describe some modifications of the beamline: new exit energy, additional focusing, insertion of a laser heater. We also describe an alternate tuning which is based on a laser pulse of 20ps. The advantages and drawbacks of this long pulse tuning are reviewed. A comparison of sensitivity to field errors and misalignment between the long pulse tuning and the nominal tuning is given.  
 
MOPKF087 The Cebaf Energy Recovery Experiment: Update and Future Plans lepton, wiggler, undulator, cathode 524
 
  • A. Freyberger, K. Beard, S.A. Bogacz, Y.-C. Chao, S. Chattopadhyay, D. Douglas, A. Hutton, L. Merminga, C. Tennant, M. Tiefenback
    Jefferson Lab, Newport News, Virginia
  A successful GeV scale energy recovery demonstration with a high ratio of peak-to-injection energies (50:1) was carried out on the CEBAF (Continuous Electron Beam Accelerator Facility) recirculating superconducting linear accelerator in the spring 2003. To gain a quantitative understanding of the beam behavior through the machine, data was taken to characterize the 6D phase space during the CEBAF-ER (CEBAF with Energy Recovery) experimental run. The transverse emittance and energy spread of the accelerating and energy recovered beams were measured in several locations to ascertain the beam quality preservation during energy recovery. Measurements also included the RF system's response to the energy recovery process and transverse beam profile of the energy recovered beam. One of the salient conclusions from the experiment is that the energy recovery process does not contribute significantly to the emittance degradation. The current status of the data analysis will be presented as well as plans for a GeV scale energy recovery experimental run with current doubling.  
 
MOPLT123 A Reduced Emittance Lattice for the NLC Positron Pre-damping Ring acceleration, vacuum, electron, emittance 827
 
  • I. Reichel, A. Wolski
    LBNL, Berkeley, California
  The Pre-Damping Ring of the Next Linear Collider has to accept a large positron beam from the positron production target, and reduce the emittance and energy spread to low enough values for injection into the Main Damping Ring. A previous version of the lattice yielded an emittance of the extracted beam which was about 20% too large. In order to get the emittance down to the required value the quadrupole magnets in the dispersive regions in the ring were moved horizontally; this modifies the damping partition numbers. In addition, the model of the wigglers has been modified to reflect more closely the magnetic field map. The new lattice design meets damping and emittance requirements. The lattice and dynamic aperture studies are presented.  
 
MOPLT124 Control System of the Small Isochronous ring acceleration, vacuum, electron, lattice 830
 
  • J.A. Rodriguez, F. Marti
    NSCL, East Lansing, Michigan
  • E. Pozdeyev
    Jefferson Lab, Newport News, Virginia
  The purpose of this paper is to describe the control system of the Small Isochronous Ring (SIR) developed and built at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). SIR is a small-scale experiment that simulates the dynamics of intense beams in large accelerators. A 20 to 30 keV hydrogen or deuterium ion bunch is injected in the ring, extracted after a variable number of turns and its longitudinal profile is studied. Information about the electronics used and software written to control different injection line, ring and extraction line elements is included. Some of these elements are magnets, electrostatic quadrupoles, electric and magnetic correctors, scanning wires, emittance measurement system, chopper and a fast Faraday cup.  
 
MOPLT127 Diagnosing the PEP-II Injection System acceleration, vacuum, injection, electron 833
 
  • F.-J. Decker, M.H. Donald, R.H. Iverson, A. Kulikov, G.C. Pappas, M. Weaver
    SLAC, Menlo Park, California
  The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar Detector has so far inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180 degrees and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high than the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond.  
 
MOPLT128 Lattice Effects due to High Currents in PEP-II acceleration, vacuum, injection, electron 836
 
  • F.-J. Decker, H. Smith, J.L. Turner
    SLAC, Menlo Park, California
  The very high beam currents in the PEP-II B-Factory have caused many expected and unexpected effects: Synchrotron light fans move the beam pipe and cause dispersion, higher order modes cause excessive heating, e-clouds around the positron beam blow up its beam size. Here we describe an effect were the measured dispersion of the beam in the Low Energy Ring (LER) is different at high and at low beam currents. The dispersion was iteratively lowered by making anti-symmetric orbit bumps in many sextupole duplets, checking each time with a dispersion measurement where a dispersive kick is generated. This can be done parasitically during collisions. It was a surprise when checking the low current characterization data that there is a change. Subsequent high and low current measurements confirmed the effect. It is located far away from any synchrotron radiation in the middle of a straight (PR12), away from sextupoles and skew quadrupoles and creates a dispersion wave of about 70 mm at high current while at low current it is negligible.  
 
MOPLT129 Identifying Lattice, Orbit, and BPM Errors in PEP-II acceleration, vacuum, injection, electron 839
 
  • F.-J. Decker
    SLAC, Menlo Park, California
  The PEP-II B-Factory is delivering peak luminosities of up to 7.4·1033 1/cm2 1/s. This is very impressive especially considering our poor understanding of the lattice, absolute orbit and beam position monitor system (BPM). A few simple MATLAB programs were written to get lattice information, like betatron functions in a coupled machine (four all together) and the two dispersions, from the current machine and compare it the design. Big orbit deviations in the Low Energy Ring (LER) could be explained not by bad BPMs (only 3), but by many strong correctors (one corrector to fix four BPMs on average). Additionally these programs helped to uncover a sign error in the third order correction of the BPM system. Further analysis of the current information of the BPMs (sum of all buttons) indicates that there might be still more problematic BPMs.  
 
MOPLT130 Bunch Pattern with More Bunches in PEP-II luminosity, acceleration, vacuum, beamloading 842
 
  • F.-J. Decker, S. Colocho, A. Novokhatski, M.K. Sullivan, U. Wienands
    SLAC, Menlo Park, California
  The number of bunches in the PEP-II B-Factory has increased over the years. The luminosity followed roughly linear that increase or even faster since we also lowered the spot size at the interaction point. The recent steps from 933 in June of 2003 to about 1320 in February 2004 should have been followed by a similar rise in luminosity from 6.5·1033 1/cm2 1/s to 9.2·1033 1/cm2 1/s. This didn't happen so far and a peak luminosity of only 7.3·1033 1/cm2 1/s was achieved. By filling the then partially filled by-3 pattern to a completely filled by-3 pattern (1133 bunches) should even give 7.9·1033 1/cm2 1/s with scaled currents of 1400 mA (HER) and 1900 mA (LER). We are typically running about 1300 mA and 1900 mA with 15% more bunches. The bunch pattern is typically by-2 with trains of 14 bunches out of 18. The parasitic beam crossings or electron cloud effects might play a role in about a 10% luminosity loss. Also the LER x-tune could be pushed further down to the ? integer in the by-3 pattern. On the other hand we might not push the beam-beam tune shift as hard as in June of 2003 since we started trickle injection and therefore might avoid the highest peak luminosity with a higher background. A mixed pattern with a by2-by3 setup (separation of 2, 3, 2, 3 ?) would give totally filled a slightly higher number of bunches (1360), but near the interaction point there would be only one parasitic crossing per beam lowering the tune shift by two.  
 
MOPLT131 Emittance Dilution Simulations for Normal Conducting and Superconducting Linear Colliders luminosity, acceleration, vacuum, beamloading 845
 
  • R.M. Jones, T.O. Raubenheimer
    SLAC, Menlo Park, California
  • N. Baboi
    DESY, Hamburg
  An electron (or positron) multi-bunch train traversing several thousand accelerator structures can be distorted by long-range wakefields left behind the accelerated bunches. These wakefields can at the very least, give rise to a dilution in the emittance of the beam and, at worst can lead to a beam break up instability. We investigate the emittance dilution that occurs for various frequency errors (corresponding to small errors made in the design or fabrication of the structure) for the GLC/NLC (Global Linear Collider/Next Linear Collider) and for TESLA (Terra Electron Superconducting Linear Accelerator). Resonant effects, which can be particularly damaging, are studied for X-band and L-band linacs. Simulations are performed with the computer codes LIAR[1] and L-MAFIA[2].

[1] R. Assman et al, LIAR, SLAC-PUB AP-103[2] The MAFIA Collaboration, MAFIA: L - The Linear Accelerator Tracking Code, CST GmbH, Darmstadt (1994)

 
 
MOPLT133 Beam Loading and Higher-band Longitudinal Wakes in High Phase Advance Traveling Wave Accelerator Structures for the GLC/NLC luminosity, acceleration, vacuum, beamloading 848
 
  • R.M. Jones, V.A. Dolgashev, Z. Li, T.O. Raubenheimer
    SLAC, Menlo Park, California
  A multi-bunch beam traversing traveling wave accelerator structures, each with a 5pi/6 phase advance is accelerated at a frequency that is synchronous with the fundamental mode frequency. As per design, the main interaction occurs at the working frequency of 11.424 GHz. However, modes with frequencies surrounding the dominant accelerating mode are also excited and these give rise to additional modal components to the wakefield. Here, we consider the additional modes in the context of X-band accelerator structures for the GLC/NLC (Global Linear Collider/Next Linear Collider). Finite element simulations, mode-matching and circuit models are employed in order to calculate the wakefield.  
 
MOPLT134 X-Band Linear Collider R&D in Accelerating Structures through Advanced Computing luminosity, acceleration, vacuum, dipole 851
 
  • Z. Li, N.T. Folwell, L. Ge, A. Guetz, V. Ivanov, K. Ko, M. Kowalski, L. Lee, C.-K. Ng, G. Schussman, R. Uplenchwar
    SLAC, Menlo Park, California
  • M. Wolf
    University of Illinois, Urbana
  The X-band linear collider design, GLC/NLC, requires accelerating structures in the main linac to operate at 65 MV/m and to be able to control emittance growth due to dipole wakefields generated by 100 micron bunch trains. The approach to high gradient has focused mainly on testing structures for acceptable breakdown rates at the desired gradient through experiments since the problem is analytically challenging. In suppressing dipole wakefields, the damped, detuned structure (DDS) has shown capable of meeting design requirements but the analysis using equivalent circuits has thus far been limited to the lowest two dipole bands. This paper describes a computational approach that addresses these design issues through large-scale simulations, using a suite of parallel electromagnetic codes developed under the DOE SciDAC Accelerator Simulation Project. Numerical results on peak field calculation, dark current generation, and wakefield computation will be presented on the H60VG4S17 DDS structure, considered to be the baseline design for the NLC.  
 
MOPLT135 Damping the High Order Modes in the Pumping Chamber of the PEP-II Low Energy Ring luminosity, acceleration, dipole, beamloading 854
 
  • A. Novokhatski, S. Debarger, F.-J. Decker, A. Kulikov, J. Langton, M. Petree, J. Seeman, M.K. Sullivan
    SLAC, Menlo Park, California
  The Low Energy Ring of the PEP-II B-factory operates with extremely high currents and short positron bunches. Any discontinuity in the vacuum chamber can excite a broad-band spectrum of the High Order Modes. A temperature rise has been found in the vacuum chamber elements in one transition from straight section to arc. The power in the wake fields was high enough to char beyond use the feed-through for the Titanium Sublimation Pump. This pumping section consists of the beam chamber and an ante-chamber. Fields, excited in the beam chamber penetrate to the ante-chamber and then through the heater wires of the TSP come out. A small ceramic tile was placed near the TSP feed-through to absorb these fields. A short wire antenna was also placed there. HOM measurements show a wide spectrum with a maximum in the 2-3 GHz region. A special water cooled HOM absorber was designed and put inside the ante-chamber part of the section. As a result, the HOM power in the section decreased and the temperature rise went down. The power loss is 750 W for a beam current of 2 A. Measurements of the HOM impedance for different bunch patterns, bunch length and transverse beam position will be presented.  
 
TUPKF012 A HOM Damped Planar Accelerating Structure gun, positron, focusing, plasma 982
 
  • A. Blednykh, H. Henke
    TET, Berlin
  The problem of very fast higher order mode (HOM) suppression, in the order of 1ns, was investigated for a planar 30GHz accelerating structure. Both, damping and detuning were considered. A sufficient suppression could be achieved by damping waveguides in every cell in vertical and in horizontal direction. Finally, a scaled-up 10GHz model was built. It is a 35 cm long aluminum structure, which was machined by high-precision milling. In order to reduce the surface gradient on the input/output coupling irises a symmetrical RF coupler was developed. The HOM damping is accomplished by coupling six damping waveguides to each accelerating cell. The waveguides are loaded by a low resitivity RF load. The whole structure with waveguides and loads was optimized by means of the computer code GdfidL. The paper gives the design criteria and the results of s-parameter and bead-pull measurements.  
 
TUPKF013 Studies on Maximum RF Voltages in Ferrite-tuned Accelerating Cavities gun, positron, focusing, plasma 985
 
  • K. Kaspar, H.G. Koenig, T. Winnefeld
    GSI, Darmstadt
  The GSI SIS100 project requires very high accelerating voltages. With ferrite-tuned synchrotron cavities the gap voltage is often strongly limited by the Q-loss effect appearing at medium dc bias fields. At low bias fields, considerably higher voltages can be reached, however. The maximum usable amplitudes over the bias region have been studied. At zero bias, the ferrites could be driven to more than a factor 3 above the Q-loss limit. Except overheating, no other problems appeared. With increasing bias, the maximum amplitudes decrease continuously to the Q-loss level. In this fall-off region there is still a tuning factor up to 2.5 available, with rf flux densities by at least a factor 2 above the Q-loss level. Measurements on small samples of the ferrite material used in the GSI cavities could be verified very well in a full-size cavity, for the most part. The tests were mainly limited by the available anode voltage and the fear of damaging the cavity. It seems possible, to generalize the main results for other ferrite materials, also. Based on the results, a possible scenario for the SIS100 rf system is given. Additionally, the results lead to an alternative cavity design for higher voltages, which is described as well.  
 
TUPKF014 Electromagnetic Design of New RF Power Couplers for the S-DALINAC gun, positron, focusing, plasma 988
 
  • M. Kunze, W.F.O. Müller, T. Weiland
    TEMF, Darmstadt
  • M.B. Brunken, H.-D. Gräf, A. Richter
    TU Darmstadt, Darmstadt
  New rf power couplers for the Superconducting Darmstadt Linear Accelerator (S-DALINAC) injector have to be designed to transfer rf power up to 2 kW to the electron beam. This allows injector operation at beam currents from 0.15 mA to 0.2 mA and electron energies up to 14 MeV. The new couplers should possibly provide a variable external Q in the range from 5·106 to 3·109 and a small transverse kick. A variable coupling is needed to allow for perfect matching in the case of beam loading and when no beam is present, respectively. The second operation stage is used for cavity diagnostics. The asymmetric field distribution of the couplers generates emittance growth of the electron beam and therefore the transverse kick has to be minimized. Electromagnetic simulations are applied to investigate different coupler designs and to localize possible problems at an early stage. Cavity external Q and transverse kick can be calculated from 3D electromagnetic eigenmode solutions. The present coaxial-coaxial input couplers at the S-DALINAC are limited to power operation below 500 W under full reflection. Therefore, to reach power operation up to 2 kW two possible new realizations of low-kick waveguide couplers for the S-DALINAC injector are presented, namely a single-waveguide and a twin-waveguide coupler.  
 
TUPKF015 Status of the Superconducting CH-Structure gun, positron, focusing, plasma 991
 
  • H. Podlech, H. Deitinghoff, H. Klein, H. Liebermann, U. Ratzinger, A.C. Sauer, R. Tiede
    IAP, Frankfurt-am-Main
  H-mode cavities (IH-DTL, IH-RFQ, 4-Vane-RFQ) have been developed and operated successfully during the last decades for ion acceleration. At the IAP Frankfurt a new type of H-mode cavity, the CH-structure is under development. This multi cell drift tube cavity is operated in the TE21- mode. Due to its mechanical rigidity, room temperature as well as superconducting versions can be realized. Superconducting CH-structures might be used especially for cw operated linacs in nuclear research facilites and applied research projects like XADS or IFMIF. A superconducting 352 MHz CH-structure (beta=0.1) with 19 gaps will be available for first tests in 2004. We present the status of the cavity and of the new cryo laboratory in Frankfurt.  
 
TUPKF016 Dynamic Lorentz Force Detuning Studies in TESLA Cavities gun, positron, focusing, plasma 994
 
  • V. Ayvazyan, S. Simrock
    DESY, Hamburg
  Dynamic detuning of the superconducting rf cavities due to Lorentz force induced mechanical excitation is a critical concern since the magnitude can approach the cavity bandwidth and require significant additional rf power for field control. In this paper, the influence of high accelerating fields on the resonance frequency in superconducting TESLA cavities is discussed. Cavities at the TESLA Test Facility have been operated at the design operating gradient close to 25 MV/m. It is shown that Lorentz force detuning constant factors are different for different cavities, significant spread have been observed.  
 
TUPKF017 Electrons Beam Dynamics of the 100 MeV Preinjector Helios for the SOLEIL Synchrotron positron, focusing, plasma, linac 997
 
  • A.S. Setty
    THALES, Colombes
  A 100 MeV electron linac is under construction, in order to inject into the booster synchrotron of SOLEIL. The linac is designed to work according to two operation modes : a short pulse mode (2 ns - 0,5 nC) and a long pulse mode (300 ns - 8 nC). Calculation of the beam dynamics, using our selfmade code PRODYN, has been carried out from the gun to the end of the linac. Special care has been taken on the gun design to avoid an overfocusing outcoming beam in order to obtain a final low emittance. Calculations results are given.  
 
TUPKF018 Surface Morphology at the Quench Site positron, focusing, plasma, linac 1000
 
  • S. Berry, C.Z. Antoine, M. Desmons
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  It has been demonstrated recently that local magnetic field enhancement can originate from roughness (e.g. steps at grain boundaries). We are willing to investigate if the quench observed in superconducting niobium cavities can be related to such morphological defects. We recently developed two kinds of tool. 1) A replica technique that allows to reproduce the internal surface of cavities (non destructive testing). 2) A morphological analysis tool. Classical roughness measurements are not adapted to determine local curvature radius.This paper describes a new topological approach aiming at a better characterization of the surface morphology. We also present results of this technique applied to replica taken from cavities at the quench site.  
 
TUPKF019 Recent Developments on Superconducting b035 and b015 Spoke Cavities at IPN for Low and Medium Energy Sections of Proton Linear Accelerators. positron, focusing, plasma, linac 1003
 
  • G. Olry, J.-L. Biarrotte, S. Blivet, S. Bousson, F. Chatelet, D. Gardès, N. Hammoudi, T. Junquera, J. Lesrel, C. Miélot, A.C. Müller, D. Ruffier, H. Saugnac, P. Szott, J.P. Thermeau
    IPN, Orsay
  Spoke cavities studies leaded by IPN-Orsay, for both XADS and EURISOL projects, are fully integrated within the 5th and 6th European Framework Programs. During 2003, several tests have been performed on the first b035 spoke cavity prototype. They have demonstrated the great potential of this type of cavity in term of RF performances (Eacc max=12.5 MV/m at T=4.2 K) and mechanical behavior (very low sensitivity to errors fabrication, good stiffness…). Following the upgrade of our cryogenic facility, we have tested, this spring, the cavity at 2 K. These new results will be presented in this paper. In parallel, the fabrication of a new spoke cavity (2-gap, 352 MHz, b015) has begun in January. While keeping the same geometry than that of the b035 cavity, we carried out significant changes on the coupler port and stiffening system designs. We report here in particular, RF calculations concerning the new location of the coupler port (in order to minimize losses due to magnetic field) and also, mechanical calculations about the new stiffening ring. Finally, we will present the preliminary thought on modular cryomodule which are based on the ?short? cryomodule concept used with the Quarter Wave Resonators for the SPIRAL-2 project.  
 
TUPKF020 Numerical Investigation on the ELETTRA 500 MHz Power Coupler positron, focusing, plasma, linac 1006
 
  • C. Pasotti, P. Craievich, A. Fabris, G. Penco, M. Svandrlik
    ELETTRA, Basovizza, Trieste
  • B. B. Baricevic
    DEEI, Trieste
  Due to the high input power required to feed a resonant cavity, the RF input coupler is a critical component for the reliability of an RF system. The 500 MHz RF input coupler for the ELETTRA cavities was specified for 150 kW input power. It is important to investigate the performance limits of the coupler in view of increasing RF power requirements. The coupler's maximum peak field and dissipation versus the input power have been studied by means of the numerical simulator HFSS. Possible improvements to the existing design have been investigated. The optimization has to take into consideration the following requirements: convenient power transmission efficiency, RF matching, suitable coupling coefficient, negligible perturbation on cavity voltage, moderate operating temperature and stress.  
 
TUPLT039 An Electrostatic Quadrupole Doublet with an Integrated Steerer lattice, electron, beamloading, antiproton 1234
 
  • C.P. Welsch, M. Grieser, J. Ullrich
    MPI-K, Heidelberg
  • C. Glaessner
    IAP, Frankfurt-am-Main
  Electrostatic storage rings have proven to be a valuable tool for atomic and molecular physics Due to the mass independence of the fields in the bending and focusing elements, different kinds of ions with the same charge/energy ratio from light protons to very heavy biomolecules, can be stored with the same field setup. The transverse dimensions of the circulating beam are controlled by electrostatic quadrupole doublets or triplets. It is essential that the fields in these lenses can be adjusted independently one from another to allow an exact control of the stored ions. In this paper, first an overview of the principle of electrostatic lenses is given. After a short discussion of fringe field effects, the results of field calculations are presented and the final layout of an electrostatic quadrupole doublet with an integrated steerer as it will be used in future electrostatic storage rings in Frankfurt and Heidelberg is discussed.  
 
TUPLT040 CSR - a Cryogenic Storage Ring at MPI-K ion, beamloading, antiproton, betatron 1237
 
  • C.P. Welsch, J. Crespo López-Urrutia, M. Grieser, D. Orlov, C.D. Schroeter, D. Schwalm, J. Ullrich, A. Wolf, R. von Hahn
    MPI-K, Heidelberg
  • X. Urbain
    UCL CRC, Louvain-la-Neuve
  • D. Zajfman
    Weizmann Institute of Science, Physics, Rehovot
  A small cryogenic storage ring is planned to be developed at MPI-K, Heidelberg. The energy in the machine will be variable from 300 keV > down to 20 keV. Electron cooling will be applied to produce a high quality ion beam. The ring shall accommodate slow, vibrationally and rotationally cooled molecular ions and highly charged ions from the EBIT ion source. Moreover, it will serve as a test facility for the low-energy antiproton ring planned within the FLAIR collaboration to be installed at the future GSI facility. A number of technological challenges have to be handled: Especially highly charged ions require a vacuum in the order below 10-13 mbar to achieve reasonable lifetimes. Therefore - and for enabling experiments with rotationally cold molecules - the complete machine will be cooled down to below 10 K. Moreover, experiments with reaction microscopes to determine the full kinematics of ion- (antiproton-) atom or molecule collisions require a bunched operation with a bunch length below 2 ns. The optical elements of the machine and the lattice functions are given and first ideas about the vacuum chamber design are described in this paper.  
 
TUPLT041 Ultra-low Energy Antiprotons at FLAIR ion, beamloading, antiproton, betatron 1240
 
  • C.P. Welsch, M. Grieser, D. Orlov, J. Ullrich, A. Wolf, R. von Hahn
    MPI-K, Heidelberg
  The Future Accelerator Facility for Beams of Ions and Antiprotons at Darmstadt will produce the highest flux of antiprotons in the world. So far it is foreseen to accelerate the antiprotons to high energies (3-15 GeV) for meson spectroscopy and other nuclear and particle physics experiments in the HESR (High Energy Storage Ring). Within the planned complex of storage rings, it is possible to decelerate the antiprotons to about 30 MeV kinetic energy, opening up the possibility to create low energy antiprotons. In the proposed FLAIR facility the antiprotons shall be slowed down in a last step from 300 keV to 20 keV in an electrostatic storage ring (USR) for various in-ring experiments as well as for their efficient injection into traps. In this energy range - especially if one thinks about realizing a real multi-purpose facility with not only antiprotons, but also various highly-charged radioactive ions to be stored and investigated - electrostatic storage rings have clear advantages compared to their magnetic counterparts. In case one envisions to even approach the eV range, electrostatic machines are the only possible choice. This contribution presents the layout and design parameters of the USR.  
 
TUPLT042 Ring of FIRE ion, beamloading, antiproton, betatron 1243
 
  • C.P. Welsch, J. Ullrich
    MPI-K, Heidelberg
  • R. Doerner, H. Schmidt-Boecking
    IKF, Frankfurt-am-Main
  • C. Glaessner, K.-U. Kuehnel, A. Schempp
    IAP, Frankfurt-am-Main
  A small electrostatic storage ring is the central machine of the Frankfurt Ion stoRage Experiments which will be build up at the new Stern-Gerlach-Center of Frankfurt university. With ion energies up to 50 keV it will allow new methods to analyze complex many-particle systems from atoms to very large bio molecules. The high luminosity of the beam allows measurements with many orders of magnitude better resolution compared to traditional measurements. It will be combined with existing experiments, like the reaction microscope COLTRIMS and the ECR ion source. In comparison to earlier designs, the ring lattice was modified in many details: Problems in earlier designs were related with e.g. the detection of light particles and highly charged ions with different charge states. Therefore, the deflectors were redesigned completely, allowing a more flexible positioning of the diagnostics. In this contribution the final design of the storage ring is presented and the layout of all elements given. First results from vacuum measurements in the recently assembled quarter ring section are summarized.  
 
TUPLT043 Status of the Cooler Synchrotron COSY-Juelich ion, beamloading, antiproton, betatron 1246
 
  • B. Lorentz, U. Bechstedt, J. Dietrich, R. Eichhorn, R. Gebel, A. Lehrach, R. Maier, D. Prasuhn, A. Schnase, H. Schneider, R. Stassen, H. Stockhorst, R. Tölle
    FZJ/IKP, Jülich
  The cooler synchrotron COSY accelerates and stores unpolarized and polarized protons and deuterons in the momentum range between 300 MeV/c to 3.65 GeV/c. To provide high quality beams, an Electron Cooler at injection and a Stochastic Cooling System from 1.5 GeV/c up to maximum momentum are available. Vertically polarized proton beams with a polarization of more than 0.80 are delivered to internal and external experimental areas at different momenta. Externally, the maximum momentum is up to date restricted to approximately 3.4 GeV/c by the extraction elements installed in COSY. In 2003 deuteron beams with different combinations of vector and tensor polarization were made available for internal and external experiments. An rf dipole was installed, which is used to induce artificial depolarizing resonances. It can be used for an accurate determination of the momentum of the stored beams. The status of the cooler synchrotron COSY is presented and future plans are discussed.  
 
TUPLT044 Delta-T Procedure for Superconducting Linear Accelerator linac, ion, beamloading, antiproton 1249
 
  • A. Bogdanov, R. Maier, Y. Senichev
    FZJ/IKP, Jülich
  Development of the tune-up procedure for a linear accelerator is the next important stage after the design is complete. Conventional delta-T procedure developed for tuning of a normal-conducting linear accelerator by Crandall allows setting up of accelerating field amplitude and phase in cavity with known phase velocity. However, application of the delta-T procedure to a superconducting linac meets some difficulties. In particular, the synchronous phase velocity in superconducting linac is determined by RF phase shift between cavities, but not by geometrical size of accelerating cells as in normal conducting linac. Additionally, in superconducting linac the smaller phase advance leads to an insensibility of particles at the cavity exit to the variation of the electric field inside the cavity. In the paper we consider the modified delta-T procedure adjusted for superconducting linac. Numerical simulations prove that by proposed technique both tasks of preservation of necessary stable region motion and providing the beam with required final energy can be successfully solved.  
 
TUPLT045 Separatrix Formalism Applied to Linacs Accelerating Particles with Different Charge to Mass Ratio ion, beamloading, antiproton, betatron 1252
 
  • A. Bogdanov, R. Maier, Y. Senichev
    FZJ/IKP, Jülich
  We have developed separatrix formalism for superconducting linear accelerators. This method allows optimizing the quasi-synchronous velocity behavior along a linac. It gives a great advantage in acceleration of particles with different charge to mass ratio. In the article design optimization of structure supposed to accelerate different particles is presented. As an example for numerical simulation superconducting injector COSY is taken.  
 
TUPLT046 Luminosity Considerations for Internal and External Experiments at COSY ion, beamloading, antiproton, betatron 1255
 
  • A. Lehrach, U. Bechstedt, J. Dietrich, R. Eichhorn, R. Gebel, B. Lorentz, R. Maier, D. Prasuhn, H. Schneider, R. Stassen, H. Stockhorst, R. Tölle
    FZJ/IKP, Jülich
  • A. Schnase
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  The future physics program at the Cooler-Synchrotron COSY in Jülich requires intense beams to provide high luminosities up to 1032cm-2s-1 for internal and external experiments. In 2003 the number of unpolarized protons could significantly be increased up to the theoretical space charge limit of COSY. This was achieved by careful study and adjustment of all subsystems in the accelerator chain of COSY. The intensities for polarized proton beams are at best an order of magnitude lower compared to one for unpolarized beams, depending on the beam current provided the injector cyclotron. Still there is some potential for further enhancement of polarized beam intensities. In this paper, luminosity considerations for polarized and unpolarized beams at COSY are presented taking into account different machine cycles and operation modes for internal and external experimental set-ups.  
 
TUPLT047 First Results of Pulsed Superconducting Half-wave Resonators ion, beamloading, antiproton, betatron 1258
 
  • R. Stassen, R. Eichhorn, F.M. Esser, B. Laatsch, R. Maier, G. Schug, R. Tölle
    FZJ/IKP, Jülich
  A pulsed linac for the cooler synchrotron COSY was projected based on superconductive half-wave resonators (HWRs). The concept of single phased resonators is a great challenge related to the requirement of accelerating protons and deuterons up to a similar energy. A cryomodule, which houses four cavities was designed in Cooperation with FZJ-ZAT, taking into account the restricted space and the special requirements of a linear accelerator. Two prototypes of the 160MHz Half-Wave Resonators (HWRs) were built at different companies. The fabrication differs slightly concerning the top and bottom parts of the cavity as well as the welding of the inner and outer conductor. First results of warm and cold measurements will be presented. The behaviour of the adjustable 4kW main coupler as well as the mechanical tuner can be tested together with the HWR in a new vertical test-cryostat.  
 
TUPLT049 Triple-spoke Cavities in FZJ ion, beamloading, antiproton, betatron 1261
 
  • E. Zaplatin, W. Braeutigam, R. Maier, M. Pap, M. Skrobucha, R. Stassen, R. Tölle
    FZJ/IKP, Jülich
  We report the situation with superconducting triple-spoke cavity activities at the research center FZJ in Juelich. The Nb prototype of the 700 MHz, beta=0.2 cavity is already in fabrication and should be tested this year. This work has been initiated for the European Spallation Source project. In the frames of the new European project of High Intensity Pulsed Proton Injector the 352 MHz, beta=0.48 cavity is under developments. This cavity should be designed, built and tested in the Lab within next few years.  
 
TUPLT050 Lattice for CELLS emittance, ion, beamloading, antiproton 1264
 
  • M. Muñoz, D. Einfeld
    CELLS, Bellaterra (Cerdanyola del Vallès)
  The CELLS is an approved project to build a national synchrotron light source in Spain. The main goals of the project are to provide a medium energy machine (3 GeV) with low emittance and top up operation, a circumference of ~280 m and at least 12 straight sections available for experiments. At present, two lattices are being considered. The first one is based in QBA optics and provides and emittance of 5 nm-rad, using existing technologies. The second one is a TBA one, with an emittance of 2 nm, where physical aperture are reduced by at least a factor 2 and gradients in the bending magnets are up to 10 T/m. We present the selected lattice, and review the main beam dynamics (energy acceptance, errors) issues.  
 
TUPLT051 Beam Optical Design of a Multi Charge Ion Recirculator for Charge Breeders emittance, beamloading, antiproton, betatron 1267
 
  • R. Cee, W. Mittig, A.C.C. Villari
    GANIL, Caen
  Ions of high charge states as required for both stable and radioactive beams in order to optimally profit from the existing accelerating voltage can be produced by means of a charge breeder. However, the energy increase obtained is accompanied by an intensity decrease due to the low efficiency of the charge breeding process. With respect to the production of radioactive beams an enhancement of the breeding efficiency would be most desirable to avoid a high power primary beam as yet inevitable to counteract the loss in intensity. For this purpose the beam optics of an ion recirculation capable to separate the desired charge state and to reinject the remaining charge spectrum has been designed. The ions extracted from both sides of the charge breeder are focused by electrostatic quadrupole doublets and bent by two 180° dipole magnets. After one revolution the optics realises horizontally a (1:1) and vertically a (1:-1) point-to-point image independent from the charge state of the ions. The second order geometric aberrations as well as most of the chromatic aberrations vanish.  
 
TUPLT054 Design of the Low-beta, Quarter-wave Resonator and its Cryomodule for the SPIRAL 2 Project emittance, beamloading, antiproton, betatron 1276
 
  • P.-E. Bernaudin, P. Bosland, S. Chel, G. Devanz, P. Hardy, F. Michel, P. de Girolamo
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  The SPIRAL 2 project, to be built in GANIL, consists of a 40 MeV linear accelerator for 5 mA of deuterons and a target-source complex for the production of exotic isotopes. The accelerator is also optimised to accelerate q/A = 1/3 ion up to 14.4 MeV/u. The three stages of the linac are a RFQ (up to 0.75 MeV/A), a low beta (0.007) and a high beta (0.12) sections consisting of quarter-wave, 88 MHz superconducting resonators. This paper focuses on the low beta cavity and its cryomodule. The cavity nominal accelerating gradient is at least 6.5 MV/m in operation conditions. RF properties of the cavities are dealt with, as well as the mechanical ones: helium pressure effects, tunability, vibrations. The cryomodule is designed so as to save longitudinal space and therefore is partly assembled in clean room.  
 
TUPLT056 ECRIS Development for the SPIRAL II Project beamloading, antiproton, betatron, cathode 1279
 
  • P. Sortais, J.-C. Curdy, A. Lachaize, T. Lamy, A. Ponton, P. Sole, T. Thuillier, J.-L. Vieux-Rochaz, D. Voulot
    LPSC, Grenoble
  The SSI/LPSC laboratory is involved in the development of high intensity sources for the driver accelerator and on the improvements of a charge breeding system for its operation inside an highly radioactive environment. We will present the results obtained for the qualification of a 5 mAe/40 KV beam of Deuteron ions dedicated to the feeding of the driver. Concerning the heavy ions, the source PHOENIX 18/28 GHz has been chosen as injector of the driver. The optimization of the source is done in order to produce reliable beams of 1mAe / O6+ and 0.3 mAe of Ar12+ at 60 KV. Theses developments are presently done with the room temperature version of PHOENIX (including a new version of the hexapole of the source). In parallel, an upgrade version of PHOENIX, using HTS coils, is under construction and is dedicated to production of very high intensity of the Argon ions (up to 1 mAe of Ar12+). A charge breeding system is also under qualification. The PHOENIX Booster source confirms that efficiency for mass around hundred can reach up to 6%. Now the efforts consist in precisely defining the 1+ beam matching for charge breeding tuning of the source (emittance measurements).  
 
TUPLT057 Beam Dynamics Studies for the Fault Tolerance Assessment of the PDS-XADS Linac Design beamloading, antiproton, betatron, cathode 1282
 
  • J.-L. Biarrotte
    IPN, Orsay
  • M. Novati, P. Pierini
    INFN/LASA, Segrate (MI)
  • H. Safa, D. Uriot
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  In order to meet the high availability/reliability required by the PDS-XADS design the accelerator needs to implement, to the maximum possible extent, a fault tolerance strategy that would allow beam operation in the presence of most of the envisaged faults that could occur in its beamline components. In this work we report the results of beam dynamics simulations performed to characterize the effects of the faults of the main linac components (cavities, deflecting and focusing magnets, …) on the beam parameters. The outcome of this activity is the definition of the possible corrective and preventive actions that could be conceived (and implemented in the system) in order to guarantee the fault tolerance characteristics of the accelerator.  
 
TUPLT058 High Intensity Linac Driver for the SPIRAL-2 Project : Design of Superconducting 88 MHz Quarter Wave Resonators (beta 0.12), Power Couplers and Cryomodules beamloading, antiproton, betatron, cathode 1285
 
  • T. Junquera, J.-L. Biarrotte, S. Blivet, S. Bousson, C. Commeaux, G. Olry, H. Saugnac
    IPN, Orsay
  • P. Balleyguier
    CEA/DAM, Bruyères-le-Châtel
  • M. Fruneau, Y. Gomez-Martinez, E. Vernay, F. Vezzu
    LPSC, Grenoble
  A Superconducting Linac Driver, delivering deuterons with energy up to 40 MeV (5 mA) and heavy ions with energy of 14.5 MeV/u (1 mA ), is proposed for the Spiral-2 radioactive beams facility. For the high energy section of the linac, a superconducting 88 MHz Quarter Wave Resonator (beta 0.12) has been designed and the optimisation of RF and mechanical performances will be presented. Based on the present state-of-art of the Superconducting RF technology, maximum electric surface field of 40 MV/m and magnetic surface field of 80 mT, have been adopted which should allow to reach an accelerating field of 7 MV/m (energy gain 3 MeV per resonator). A first complete prototype is under construction. The high intensity deuteron beam specifications have imposed the design of an original power coupler (maximum power 20 KW). The RF, mechanical, and thermal characteristics will be presented. The design of the cryomodule for this high energy section, integrating two QWR with its associated equipments (couplers, tuners, helium tanks), will be presented.  
 
TUPLT059 Evolution of Optical Asymmetries in the Elettra Storage Ring beamloading, antiproton, betatron, cathode 1288
 
  • F. Iazzourene, S. Di Mitri, E. Karantzoulis, L. Tosi
    ELETTRA, Basovizza, Trieste
  Optical asymmetries have been measured and analyzed, before and after the magnet realignments. One way is to compare theoretical to measured orbit response matrices. Another way is to analyze the measured response matrix itself, by comparing the measured effects at identical optical positions. To evaluate the effects of the sextupoles on the optical asymmetries, the measurements have been performed with the sextupoles ON and OFF. The impact of a partial realignment is also analyzed both by varying the quadrupole excitations as well as by performing dispersion and coupling measurements. The results are presented in this paper.  
 
TUPLT060 Production of Radioactive Ion Beams for the EXCYT Facility ion, target, beamloading, antiproton 1291
 
  • M. Menna, G. Cuttone, M. Re
    INFN/LNS, Catania
  The EXCYT facility (EXotics with CYclotron and Tandem) at the INFN-LNS is based on a K-800 Superconducting Cyclotron injecting stable heavy-ion beams (up to 80 MeV/amu, 1 emA) into a target-ion source assembly to produce the required nuclear species, and on a 15 MV Tandem for post-accelerating the radioactive beams. After thermal ANSYS simulations, during May 2003 the Target-Ion Source assembly (TIS) was successfully tested at GANIL under the same operational conditions that will be initially used at EXCYT. Yields and production efficiencies for 8,9Li were compatible with the ones obtained at SPIRAL. Following suggestions by the Referees and the LNS Research Division, we decided to deliver 8Li as the first EXCYT radioactive beam (primary beam 13C). This choice also takes in account the availability of MAGNEX in 2004 as well as the requests and the first results obtained by the Big Bang collaboration. The commissioning of the EXCYT facility is foreseen by the end of 2004 together with the start of nuclear experiments program. In this poster we also report prospective ion beams currently in development.  
 
TUPLT061 Production and Transport of Radioactive Francium for Magneto-optical Trapping ion, target, beamloading, antiproton 1294
 
  • G. Stancari, R. Calabrese, B. Mai, G. Stancari, L. Tomassetti
    INFN-Ferrara, Ferrara
  • S.N. Atutov, V. Guidi
    UNIFE, Ferrara
  • V. Biancalana, A. Burchianti, A. Khanbekyan, C. Marinelli, E. Mariotti, L. Moi, S. Veronesi
    UNISI, Siena
  • L. Corradi, A. Dainelli
    INFN/LNL, Legnaro, Padova
  • P. Minguzzi, S. Sanguinetti
    UNIPI, Pisa
  An innovative facility for the production and trapping of francium isotopes is operating at the INFN laboratories in Legnaro, Italy. The goal is to obtain a dense cloud of cold and possibly polarized radioactive atoms for a wide range of fundamental studies. Among them are high-resolution laser spectroscopy, alpha-decay asymmetries from deformed nuclei, and tests of the standard model at low transferred momenta. The production of francium is achieved by sending a 100-MeV oxygen-18 beam from the Tandem-XTU accelerator on a thick gold target. The extraction of Fr+ is enhanced by heating the target to 1200 K and by biasing it at +3 kV. The ions are transported to the magneto-optical trap (MOT) through a 7-m electrostatic beam line. The diagnostic systems for monitoring the beam intensity (105 ions/s) are based on silicon detectors sensitive to the alpha particles from Fr decays. Beams of stable Rb+ can also be used for optimizing the transport and trapping processes. Prior to injection into the MOT the beam is neutralized and released in atomic form by a heated yttrium or zirconium foil. Details on the production, transport and neutralization processes are presented.  
 
TUPLT062 Design of the Proton Beam Line for the Trade Experiment ion, beamloading, antiproton, betatron 1297
 
  • C. Ronsivalle, L. Picardi
    ENEA C.R. Frascati, Frascati (Roma)
  • S. Monti, F. Troiani
    ENEA C.R. Rome, Rome
  The TRADE (Triga Accelerator Driven Experiment)experiment, to be performed in the TRIGA reactor of the ENEA-Casaccia centre consists in the coupling of a 140-300 MeV, 0.5 mA proton beam produced by a cyclotron to a target hosted in the central thimble of the reactor scrammed to sub-criticality. A 30 m long beamline has been designed to transfer the beam injecting it from the top of the pool with special care of having low losses in TRIGA building where a limited shielding of the line is possible. A particular attention was paid to reduce the number and size of elements in the last part of the beamline that are immersed in the pool's water. The paper presents a description of the beam line, the design criteria and the results of beam dynamics calculations.  
 
TUPLT063 Laser Temporal Pulse Shaping Experiment For SPARC Photoinjector ion, laser, beamloading, antiproton 1300
 
  • C. Vicario, A. Ghigo
    INFN/LNF, Frascati (Roma)
  • I. Boscolo, C. Vozzi
    Universita' degli Studi di Milano, MILANO
  • S. Cialdi, A.F. Flacco
    INFN-Milano, Milano
  • M. Nisoli, G. Sansone, S. Stagira
    Politecnico/Milano, Milano
  • M. Petrarca
    INFN-Roma, Roma
  Laser for driving high brightness photoinjector have to produce UV square pulse which is predicted to be the optimum profile for emittance compensation in advanced photoinjectors. The longitudinal laser pulse distribution, according to numerical simulations for the SPARC photoinjector, must be square with rise and fall time shorter than 1 ps and flat top variable up to 10 ps FWHM. In this paper we report the results of pulse shaping obtained using an acousto-optic (AO) programmable dispersive filter (DAZZLER). The DAZZLER was used to perform spectral amplitude and phase modulation of the incoming 100 fs Ti:Sapphire pulses. Because of the finite length of the crystal the maximum duration of the shaped pulse is 6 ps. To overcome this limitation we used a configuration in which the laser pulses passed twice through the AO filter. A dispersive glass section was also used to lengthen the pulse with a single pass in the DAZZLER. In this paper we report the experimental setup, hardware description and time and frequency domain measurements.  
 
TUPLT065 Beams from RF Ovens and ECR Ion Sources injection, laser, beamloading, antiproton 1303
 
  • M. Cavenago
    INFN/LNL, Legnaro, Padova
  • T. Kulevoy, S. Petrenko
    ITEP, Moscow
  Beam of silver, copper and recently platinum were produced with the radiofrequency oven technique. The ECRIS (Electron Cyclotron Resonance Ion Source) can be conveniently considered as a charge breeder for any injection device; this approach allows to compare the injection of metals from ovens with other techniques discussed in the literature, like the injection from mevva (Metal Vapor Vacuum Arc) sources or the injection of single charged RIB (radioactive ion beams) or the simple injection of heavy gas. Extensive experiments extracting beams of copper (charge up 13+) or silver (charge up to 19+) or xenon (charge up 20+) with the same ECRIS condition are described, and advantage of rf oven over gas injection are discussed; in particular the oven crucible can be easily voltage biased up to -400 V, to modify ECRIS plasma shape. Heating the tantalum crucibles over 2300 K (average temperature) requires careful axial alignment to avoid the formation of hot spots; preliminary evidence of this effect and its numerical modeling are also described.  
 
TUPLT066 Study of a High-current 176 MHz RFQ as a Deuteron Injector for the SPES Project injection, laser, beamloading, antiproton 1306
 
  • M. Marchetto, M. Comunian, E. Fagotti, A. Palmieri, A. Pisent
    INFN/LNL, Legnaro, Padova
  The SPES project, aimed at the construction of a RIB facility at LNL, is initially based on the use of a primary proton beam, but it foresees a future development based on the usage of deuterons and light ions. In this article we report about the preliminary study of a 176 MHz RFQ to be used as an injector for such kind of beams. The structure explored foresees a ?four ladder? symmetric resonator, built in brazed copper. In particular beam dynamics, electrodynamics design and preliminary thermo-structural analysis of the cavity is presented.  
 
TUPLT069 Approaching to a Mono-modal Accelerating Cavity based on Photonic Band-gap Concepts injection, laser, beamloading, antiproton 1309
 
  • M.R. Masullo
    INFN-Napoli, Napoli
  • A. Andreone, E. Di Gennaro, G. Lamura
    Naples University Federico II, Napoli
  • F. Francomacaro, M. Panniello, V.G. Vaccaro
    Naples University Federico II and INFN, Napoli
  • G. Keppel, V. Palmieri, D. Tonini
    INFN/LNL, Legnaro, Padova
  One of the main problem of high intensity accelerators is the presence of high order modes (HOMs) which might degrade the beam quality. Accelerating cavities require HOMs suppression while keeping high quality factor (Q) fundamental mode. Both these requirements can be hardly met in closed metallic cavities. In low frequency cases and for particular geometries it is possible to partially suppress HOMs, but at high frequencies and for superconducting cavities configuration becomes cumbersome and technically unviable. We propose here a high Q cavity based on Photonic Band Gap (PBG) concepts, operating in the microwave region. The cavity consists of a two-dimensional lattice, where posts (dielectric, metallic or superconducting) are sandwiched by two conducting plates. This sandwich exhibits two kinds of frequency bands: 'pass-bands' and 'stop-bands'. It is possible to localize modes in an equivalent cavity obtained by removing posts. These modes are localized in the 'cavity'. In this way, one can obtain a quasi-mono-modal cavity: high Q fundamental mode and HOMs falling into the pass bands. We will present the study, the optimisation and the measurements of our metallic (Copper) PBG structure working in the 2-20 GHz range. The development of a different cryogenic set-up, necessary to characterise an all superconducting or an hybrid (dielectric/metallic) structure, is under way.  
 
TUPLT071 A 5 MeV Electron Linac for Radiation Processing injection, laser, beamloading, antiproton 1315
 
  • A. Trifirò, L. Auditore, R.C. Barnà, D. De Pasquale, A. Italiano, M. Trimarchi
    INFN - Gruppo Messina, S. Agata, Messina
  In recent years, radiation processing is rapidly growing in various field of industrial treatments and scientific research as a safe, reliable and economic technique. To match the requirements of several applications, a 5 MeV, 1 kW electron linac has been developed at the Dipartimento di Fisica (Università di Messina), in collaboration with the ENEA Accelerators Group (Frascati- Rome). This self- containing standing wave accelerator, driven by a 3 GHz, 2.5 MW Magnetron, has been designed, by means of the SUPERFISH and PARMELA codes, in such a way as to obtain an autofocusing structure, that will be used to develop a transportable system for 'in-situ' industrial radiography and X-ray digital tomography. For this accelerator, compact pulse forming circuits have been properly developed for the magnetron and the cathode, and pulse frequency can be varied ranging from 1 to 300 Hz, thus allowing the study of several applications of radiation processing. Main features of the accelerating structure, as well as beam spot dimensions, surface dose distribution and electron beam energy range will be described.  
 
TUPLT072 Dual Harmonic Acceleration with Broadband MA Cavities in J-PARC RCS injection, laser, beamloading, antiproton 1318
 
  • M. Yamamoto
    JAERI, Chiba-ken
  • S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Yoshii
    KEK, Ibaraki
  • M. Nomura, A. Schnase, F. Tamura
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  In the J-PARC RCS rf system, since the fundamental rf acceleration voltage and the 2nd higher harmonic one are applied to each cavity, the impedance of hte cavity has a broadband characteristic. The Q-value of the cavity is chosen to make the higher harmonic beam loading effect as small as possible. The analysis of the amplifier and the beam loading effect on the dual harmonic rf system is described.  
 
TUPLT073 Observation of Coupling Resonance in HIMAC Synchrotron injection, laser, beamloading, antiproton 1321
 
  • T. Uesugi, T. Fujisawa, K. Noda, S. Shibuya, D. Tann, H. Uchiyama
    NIRS, Chiba-shi
  • Y. Hashimoto
    KEK, Ibaraki
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  Coupling resonance was observed at operating points near to Qx-Qy=1. Two-dimensional profile of a beam at its equilibrium was measured, and it was found that the beam was inclined in transverse when the operating point is near to the resonance condition. We will present the detail of the measurement and the results.  
 
WEPKF037 Structural Analysis of an Integrated Model of Short Straight Section, Service Module, Jumper Connection and Magnet Interconnects for the Large Hadron Collider kicker, bunching, beamloading, antiproton 1684
 
  • S. Dutta, J. Dwivedi, A. Kumar, H.C. Soni
    CAT, Indore (M.P.)
  • B. Skoczen
    CERN, Geneva
  The Short Straight Section (SSS) of the Large Hadron Collider (LHC) houses a twin quadrupole.The cryogens are fed to the SSS through a Jumper Connection between service modules of Cryogenic Distribution Line (QRL) and SSS.A Finite Element analysis has been performed in collaboration with CERN for the unified model of SSS of LHC,consisting of cold mass, cold supports,vacuum vessel and its bellows, interconnects, jumper connection and alignment jacks. The model has been developed to understand coupling between the quadrupole magnet and the service module due to ground motion and during the realignment or global smoothening of the LHC arc. The model incorporates experimental stiffness values for support posts, internal pipes and jacks and calculated stiffness for magnet-to-magnet interconnects. The computation space and time has been reduced by executing a two step linear static analycal approach with an initial trial analytical approach cycle in which the program estimates the behavior of the flexibles. A special routine is developed within ANSYS,using APDL which selects the correct secant stiffness of flexibles(by applying a user interactive logical algorithm)from their non-linear force displacement characteristics.  
 
WEPLT066 Beam Dynamics Study for PETRA III Including Damping Wigglers focusing, antiproton, bunching, coupling 1996
 
  • Y.L. Li, K. Balewski, W. Decking
    DESY, Hamburg
  Damping wigglers will be installed in the storage ring PETRA III to control the beam emittance to 1 nmrad. These wigglers will produce linear and nonlinear perturbations on beam dynamics. A new expanded transport matrix method is developed to solve linear dynamics, and used to match linear lattice functions. The symplectic method is adopted to track particle through the whole ring including the damping wigglers. Halbach?s formulae are used to describe the wiggler field. The main parameters of the wigglers are derived from field calculations. In order to avoid dangerous resonances, tune scanning is implemented to find suitable working points. According to presently known field quality, the nonlinear effects of damping wigglers will not degrade the performance of PETRA III and the dynamic aperture is still larger than the physical aperture.  
 
WEPLT067 Space Charge Problem in Low Energy Super-conducting Accelerator antiproton, bunching, coupling, electron 1999
 
  • N.E. Vasyukhin, R. Maier, Y. Senichev
    FZJ/IKP, Jülich
  At present the super-conducting option of linear accelerators is considered for low energy, and new type of RF cavities is considered for this purpose. However, together with electrodynamics problems we should solve the transverse stability problem, since in structures with external focusing elements the focusing period is longer, and in higher accelerating field the defocusing factor increases as well. In this paper we consider the transverse stability problem, taking into account the non-linear space charge problem. The fundamental mechanism of hallo creation in super-conducting linear accelerators is investigated to minimize the particle losses. The theoretical results are supported by numerical simulation.  
 
WEPLT068 Momentum Compaction Factor and Nonlinear Dispersion at the ANKA Storage Ring antiproton, bunching, coupling, booster 2002
 
  • A.-S. Müller, A. Ben Kalefa, I. Birkel, E. Huttel, M. Pont, F. Pérez
    FZK-ISS-ANKA, Karlsruhe
  The ANKA electron storage ring operates in the energy range from 0.5 to 2.5 GeV. In order to improve machine performance a precise modelling of linear and nonlinear optics is mandatory. Apart from higher order chromaticity also momentum compaction factor and dispersion have to be controlled. In this framework, the higher order momentum compaction factor has been determined exploiting the extraordinary precision of the resonant spin depolarisation method. Furthermore the nonlinear horizontal dispersion was measured as a function of the momentum deviation for different chromaticities. This paper discusses the experimental results and compares the findings to different simulations.  
 
WEPLT069 Investigation of Scraper Induced Wake Fields at ANKA antiproton, bunching, coupling, booster 2005
 
  • A.-S. Müller, I. Birkel, E. Huttel, M. Pont, F. Pérez
    FZK-ISS-ANKA, Karlsruhe
  • F. Zimmermann
    CERN, Geneva
  The ANKA synchrotron light source operates in the energy range from 0.5 to 2.5 GeV. Typical requirements for light sources include small beam sizes, large lifetimes and high currents to provide the highest possible photon flux. The understanding of impedance and instability related issues is very important in order to improve the machine performance, in particular when small aperture insertion devices are installed that require protection by a scraper. In the framework of an impedance survey the transverse and longitudinal wake fields induced by a vertical scraper have been measured and analysed. This paper reports the beam observations and compares them with the expectation.  
 
WEPLT070 Studies of Current Dependent Effects at ANKA antiproton, bunching, coupling, booster 2008
 
  • A.-S. Müller, I. Birkel, E. Huttel, M. Pont, F. Pérez
    FZK-ISS-ANKA, Karlsruhe
  • F. Zimmermann
    CERN, Geneva
  The ANKA electron storage ring is operated at energies between 0.5 and 2.5 GeV. A major requirement for a synchrotron light source, such as ANKA, is to achieve a high beam current. A multitude of mostly impedance related effects depend on either bunch or total beam current. This paper gives an overview over the various beam studies performed at ANKA in this context, specifically the observation of current dependent detuning, the dermination of the bunch length change with current from a measurement of the ratio between coherent and incoherent synchrotron tune and an assessment of the effective longitudinal loss factor from the current dependent horizontal closed orbit distortion.  
 
WEPLT071 Longitudinal Resonances and Emittance Growth Using QWR/HWR in a Linac antiproton, coupling, booster, focusing 2011
 
  • P. Bertrand
    GANIL, Caen
  In the frame of the SPIRAL II project at GANIL, we present an analytical approach allowing us to understand in a simple way the longitudinal behaviour of a beam , transmitted in bunching mode or accelerated in a Linac designed with QWR or HWR cavities. In particular, we make appear the strong relationship with the Henon map properties.  
 
WEPLT072 Preliminary Design of the RF Systems for the SPIRAL 2 SC Linac antiproton, coupling, booster, focusing 2014
 
  • M. Di Giacomo, B. Ducoudret, J.F. Leyge
    GANIL, Caen
  • J.F. Denis, M. Desmons, M. Luong, A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  In the SPIRAL 2 Linac, a 5 mA, CW , Deuteron beam is accelerated up to 40 MeV, through a normal conducting RFQ and 26 independent-phase SC quarter wave resonators, working at 88,05 MHz. Tube and solid state amplifiers derived from the standard FM transmitter modules are used while a new digital control system has been designed for the feed-back and feed-forward control system. The paper presents the power and low level systems for both the normal and superconducting cavities and results of simulations of the RF system in operating conditions.  
 
WEPLT073 VDHL Design and Simulation of a Fast Beam Loss Interlock for TTF2 antiproton, coupling, booster, focusing 2017
 
  • A. Hamdi
    CEA/Saclay, Gif-sur-Yvette
  • M. Luong
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • M. Werner
    DESY, Hamburg
  The TTF2 fast beam loss interlock provides different modes of protection. Based on the differential beam charge monitoring over a macropulse, a pulse slice or bunch-by-bunch, the signal processing time should be as short as the bunch repetition period (110 ns). The signal delivered by the toroid-like inductive current transformer always shows an envelope droop due to its self-inductance to resistance ratio. When the macropulse length is comparable to this ratio, the charge of each bunch must be derived from the difference of the top to the bottom level on the signal. This necessity combined to the various protection modes leads to a digital implementation. All the processing functionalities are designed with VHDL for a Xilinx FPGA. Because the interlock involves other control signals in addition to the toroid signal with specific shapes, which cannot be easily reproduced for the design validation before the TTF2 completion, VHDL provides meanwhile the possibility for an exhaustive validation of the system with a software test bench including all timing information.  
 
WEPLT075 Status Report on the Beam Dynamics Developments for the SPIRAL 2 Project antiproton, coupling, booster, focusing 2020
 
  • R. Duperrier, D. Uriot
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • P. Bertrand, F. Varenne
    GANIL, Caen
  • J.-L. Biarrotte
    IPN, Orsay
  • J.-M. De Conto
    ISN, Grenoble
  • E. Froidefond
    LPSC, Grenoble
  • N. Pichoff
    CEA/DAM, Bruyères-le-Châtel
  The driver for the SPIRAL 2 project aims to accelerate a 5 mA D+ beam up to 20 A.MeV and a 1 mA beam for Q/A=1/3 up to 14.5 A.MeV. It operates in a continuous wave regime (cw), is designed for a maximum efficiency in the transmission of intense beams. Recent studies have led to change the reference design. The current design consists in an injector (ECR sources + LEBTs with the possibility to inject from several sources + a Radio Frequency Quadrupole) followed by a superconducting section based on an array of independently phased cavities where the transverse focalisation is performed by warm quadrupoles. This paper presents the beam dynamics studies associated to these new choices, the HEBT design and the fast chopping in the MEBT.  
 
WEPLT076 SPIRAL 2 RFQ Design antiproton, coupling, booster, focusing 2023
 
  • R. Ferdinand, G. Congretel, A. Curtoni, O.D. Delferriere, A. France, D.L. Leboeuf, J. Thinel, J.-C. Toussaint
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • M. Di Giacomo
    GANIL, Caen
  The SPIRAL2 RFQ is designed to accelerate at 88MHz two kinds of charge-over-mass ratio, Q/A, particles. The proposed injector can accelerate a 5 mA deuteron beam (Q/A=1/2) or a 1 mA particles beam with q/A=1/3 up to 0.75 MeV/A. It is a CW machine which has to show stable operation, provide the request availability, have the minimum losses in order to minimize the activation constraints and show the best quality/cost ratio. It will be a 4-vane RFQ type, with a mechanical assembly, the global assumption being to build an RFQ without any brazing step. Extensive modelisation was made to ensure a good vane position under RF. A 1-m long hot model prototype is under construction in order to validate the manufacturing concept.  
 
WEPLT077 DESIGN OF A FULL-CUSTOM ACCURATE I-Q MODULATOR antiproton, booster, focusing, target 2026
 
  • M. Luong, M. Desmons
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  The I-Q modulator is a key component in a digital Low Level RF (LLRF) system for amplitude and phase feedbacks. Its residual errors in offset or gain have a strong impact on the dynamic and accuracy of the feedback loops. For some frequencies, commercial I-Q modulators are available on the market. But even in that case, these components are usually designed for broadband communication purposes, and their performances in term of residual errors may not fit the strict requirements on the final amplitude and phase loop stability. Since LLRF systems for accelerators are typically narrow-banded, i.e. limited to few MHz, it is possible to achieve a high directivity and a very accurate coupling for hybrids, and an excellent matching for all subcomponents in a fully custom design. This approach guarantees the lowest residual errors for an I-Q modulator. The principle for the design and the process for the optimization are presented in this paper.  
 
WEPLT078 The IFMIF High Energy Beam Transport Line antiproton, booster, focusing, target 2029
 
  • D. Uriot, R. Duperrier, J. Payet
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  The IFMIF project (International Fusion Materials Irradiation Facility) requests two linacs designed to accelerate 125 mA deuteron beams up to 40 MeV. The linac has to work in CW mode and uses one RFQ and 10 DTL tanks. After extraction and transport, the deuteron beams with strong internal space charge forces have to be bunched, accelerated and transported to target for the production of high neutron flux. This paper presents the high energy beam transport line which provides a flat rectangular beam profile on the liquid lithium target. Transverse uniformisation is obtained by using non-linear mutipole lenses (octupoles and duodecapoles). Beam dynamics with and without errors has been study.  
 
WEPLT079 Non Linear Beam Dynamics and Lifetime on the SOLEIL Storage Ring antiproton, booster, target, beamloading 2032
 
  • P. Brunelle, A. Loulergue, A. Nadji, L.S. Nadolski
    SOLEIL, Gif-sur-Yvette
  The incidence of several non-linear effects on the energy acceptance and beam lifetime has been investigated, using the BETA and TRACY II tracking codes. The effect of all magnets multipolar components has been checked on the working point (18.20; 10.30), especially the decapolar component induced by the H-corrector. The dipolar field, which is created by additional coils in the sextupoles, generates a significant decapolar component which, associated to the distributed dispersion, can reduce significantly the dynamic acceptance at large energy deviations. This effect depends on the natural closed orbit to be corrected: corrector strengths and cross talk between the different decapolar components. Moreover, the sensitivity to the number of correctors, used for correction, has been evaluated. The effect of insertions devices has also been studied, integrating field maps generated by the RADIA code into the tracking codes. With undulators, such as an in-vacuum U20 and an Apple II type HU80 (with different polarization modes), it was shown that the transverse field in-homogeneity and the focusing effects generating beta-beat can affect severely the energy acceptance and the beam lifetime because of resonance excitation.  
 
WEPLT080 Study of Resistive-wall Effects on SOLEIL antiproton, booster, target, beamloading 2035
 
  • R. Nagaoka
    SOLEIL, Gif-sur-Yvette
  The presence of low-gap chambers for insertion devices, along with a relatively small vertical gap of 25 mm chosen for the standard vacuum chambers, implies a significant influence of the resistive-wall on the beam in the future SOLEIL storage ring. A systematic approach was taken to quantify the net contribution by taking into account all local variations of the non-circular chamber cross-sections as well as beta functions. Low multibunch instability thresholds were found in both transverse planes, indicating the necessity of cures, by means of transverse feedback and/or chromaticity shifts. An effort was made to evaluate the effect of metallic coating, particularly that of NEG, which was adopted in all straight sections. The dependence on both resistivity and thickness of NEG was followed. It is found that, the NEG coating nearly doubles the reactive part of the impedance in the frequency range seen by the beam. Implication on the reduction of the transverse mode-coupling instability threshold is discussed. Incoherent tune shifts arising from the non-circular chamber cross-section were also evaluated, including a non-negligible NEG contribution in the short-range wakes.  
 
WEPLT081 Numerical Evaluation of Geometric Impedance for SOLEIL impedance, antiproton, booster, target 2038
 
  • R. Nagaoka
    SOLEIL, Gif-sur-Yvette
  Good knowledge and minimisation of the coupling impedance is of great importance for the future storage ring SOLEIL, envisaged to operate in both high current multibunch and high bunch intensity modes. Three-dimensional computations of the geometric impedance of various vacuum chamber components have been made with the code GdfidL, which allows parallel processing with a cluster of computers, rendering the computation with a small mesh size and a long integrated distance feasible. Many treated objects were found to exhibit large asymmetry in the two transverse planes, as well as resonant behaviour at high frequencies, both of which being non-straightforward to follow with the conventional analytical methods and 2-dimensional calculations. In particular, strongly trapped modes found for the flange impedance resulted in an unacceptably low vertical multibunch instability threshold, which urged a modification of the original cavity-like structure. The dependence of the dipole chamber impedance on the vertical slot size was followed to determine the optimal slot opening. Characteristics of the total broadband impedance obtained, along with relative contributions are also presented.  
 
WEPLT082 General Performances of the Injection Scheme into the SOLEIL Storage Ring impedance, injection, antiproton, booster 2041
 
  • M.-A. Tordeux, J. Da Silva, P. Feret, P. Gros, P. Lebasque, A. Mary
    SOLEIL, Gif-sur-Yvette
  The injection scheme of the electron beam into the Storage Ring of the SOLEIL synchrotron is presented. It corresponds to the new SOLEIL optics : 12 meter long straight section, 2.75 GeV energy, with in addition the requirement for top-up injection mode. Pulsed magnets are described, and in particular the passive septum magnet, the transverse position of which can be adjusted so as to optimise the Touschek beam Lifetime. Tracking of particles has been performed over a large number of turns, taking into account the magnet errors, the high chromaticities and the physical apertures all along the machine (limited vertical apertures due to low gap undulators). Statistical efficiency of the injection has been deduced. Specific requirements for top-up injection have been examined, such as the closure of the injection bump, the residual vertical field and the leakage fields from septa.  
 
WEPLT083 Coherent and Incoherent Tune Shifts Deduced from Impedance Modelling in the ESRF-Ring injection, antiproton, booster, target 2044
 
  • T.F. Günzel
    ESRF, Grenoble
  In single bunch the detuning of the transverse modes m=0,1 and -1 are calculated on the base of an impedance model contructed from element-wise wakefield calculation and the resistive wall impedance of the ESRF-ring. As the vacuum chambers of the ESRF storage ring have notably flat cross sections incoherent wake fields have an impact on the tune shifts as well as coherent wake fields. Compared to tune shift measurements in single bunch the calculated transverse mode detuning can explain half of the tune shift in the vertical plane and almost completely the tune shift in horizontal plane.  
 
WEPLT084 Experimental Frequency Maps for the ESRF Storage Ring injection, antiproton, booster, target 2047
 
  • Y. Papaphilippou, L. Farvacque, E. Plouviez, J.-L. Revol, A. Ropert
    ESRF, Grenoble
  • J. Laskar
    IMCCE, Paris
  • Ch. Skokos
    Academy of Athens, Athens
  Experimental frequency maps have already revealed many unknown characteristics of the ESRF storage ring non-linear dynamics. In the past year, several efforts were undertaken in order to establish this technique as an operational on-line tool. The acquisition time was significantly reduced by collecting data from a dedicated fast BPM system. The problem of beam decoherence was limited by establishing a method for accurate tune determination in a small number of turns, using the information from all the BPMs around the ring. The possibility to explore the off-momentum dynamics by exciting the beam, with synchronous transverse and longitudinal kicks was also investigated. Finally, measurements of resonance driving term amplitudes and phase advances were used to identify the efficiency of resonance corrections.  
 
WEPLT085 Vertcal Effective Impedance Mapping of the ESRF Storage Ring injection, impedance, antiproton, vacuum 2050
 
  • T. Perron, L. Farvacque, E. Plouviez
    ESRF, Grenoble
  Transverse impedance increase due to installation of low gap vacuum chambers is a general effect observed in synchrotron light sources. ESRF has been sensitive to this increase of impedance, as its single bunch threshold has dramatically decreased. This paper presents a method based on closed orbit distortion measurements, witch allows to measure locally the vertical effective impedance. Results of measurements performed on low gap vacuum chambers and in-vacuum ondulators are presented. As an extension to this experiment, a new global method is discussed. This method, also based on closed orbit measurement allows measuring simultaneously all areas of high impedance in the machine  
 
WEPLT086 Non Gaussien Transverse Distributions in a Stochastic Model for Beam Halos injection, impedance, antiproton, vacuum 2053
 
  • N. Cufaro Petroni
    INFN-Bari, Bari
  • S. De Martino, S. De Siena, F. Illuminati
    Universita' degli Studi di Salerno, Dipartimento di Fisica E.R. Caianiello, Baronissi
  The formation of the beam halo in charged particle accelerators is studied in a dynamical stochastic model for the collective motion of the particle beam. The density and the phase of the charged beam obey a set of coupled nonlinear hydrodynamic equations with time-reversal invariance. The linearized theory for this collective dynamics is given in terms of a classical Schroedinger equation. Self-consistent solutions with space-charge effects lead to quasi-stationary beam configurations with enhanced transverse dispersion and transverse emittance growth. In the limit of a frozen space-charge core it is possible to determine and study the properties of stationary, stable core-plus-halo beam distributions. We explore the effect of non-Gaussian transverse distributions. In this case the underling stochastic process is allowed to jump, and the transverse distribution tails are heavier than in the Gaussian case giving rise to a halo effect. The stationary transverse distribution plays the role of an attractor for every other distribution, and we give an estimation of the time needed by a non stationary, halo-free distribution to relax toward the stationary distribution with a halo.  
 
WEPLT090 Nonlinear Evolution of the Beam in Phase Space at Elettra injection, impedance, antiproton, vacuum 2056
 
  • S. Di Mitri, L. Tosi
    ELETTRA, Basovizza, Trieste
  Phase space in the Elettra storage ring has been investigated. The beam is kicked and the coordinates of the bunch centroid are acquired for at least 1000 turns. A Hilbert transform has been used to deduce the evolution of beam phase space from position coordinates. Several nonlinear effects have been detected, such as the amplitude dependence of the betatron tune, the presence of high order and coupling resonances. Fixed points have been evidenced as well as the behaviour of the beam in their neighbourhood. Scans in lifetime versus tune confirm the limiting effect of the observed resonances on the region of regular motion.  
 
WEPLT091 Frequency Map Analysis with the Insertion Devices at ELETTRA impedance, antiproton, vacuum, booster 2059
 
  • S. Di Mitri, L. Tosi
    ELETTRA, Basovizza, Trieste
  • L.G. Liu
    SSRF, Shanghai
  Frequency map analysis is a very efficient technique for the understanding of the resonances which may affect the stability of the electrons. Measurements correlated to simulations can provide a method to improve beam lifetime and injection efficiency that is particulary important in the case of top up operation. In this paper, the results of frequency map measurements and simulations for the ELETTRA storage ring are presented both for the bare lattice as well as for the case in which insertion devices are operational.  
 
WEPLT092 Equilibrium Longitudinal Distribution for Localized Regularized Inductive Wake impedance, antiproton, vacuum, booster 2062
 
  • S. Petracca, T. Demma
    U. Sannio, Benevento
  • K. Hirata
    GUAS, Kanagawa
  In a recent paper [*] we have shown that a localized wake assumption and the Gaussian approximation for the longitudinal beam distribution function can be used to understand the nature of the stationary solutions for the inductive wake, by comparison between the resulting map and the Haissinski equation, which rules the (less realistic) case of a uniformly distributed wake. In particular we showed the non-existence of solutions of Haissinski's equation when the inductive wake strength exceeds a certain threshold [**] to correspond to the onset of chaos in the map evolving the moments of the beam distribution from turn to turn. In this paper we use the same formalism to confirm that as noted in [**] for Haissinski's equation, a steady state solution for the longitudinal phase space distribution function always exists if a physically regularized inductive wake, which satisfies an obvious causality condition, is used.

* S. Petracca and Th. Demma, Proc. of the 2003 PAC, IEEE Press, New York, 2003, ISBN 0-7803-7739-9, p.2996.** Y. Shobuda and K. Hirata, Part. Accel. vol. 62, 165 (1999).

 
 
WEPLT093 Electromagnetic Fields of an Off-axis Bunch in a Circular Pipe with Finite Conductivity and Thickness - I impedance, antiproton, vacuum, booster 2065
 
  • S. Petracca, L. Cappetta, T. Demma
    U. Sannio, Benevento
  The electromagnetic field produced by a bunched beam in a circular pipe is usually computed under the assumption that the field penetration(skin depth) is far less than the wall thickness. Chao [*] gave a formula which exploits the wall thickness, but his result is restricted to the monopole term. Piwinski [**] treated the case of a metal coated ceramic wall, when the coating thickness is much smaller than the skin-depth, but his analysis is also limited to the monopole term.In this paper we solve the problem in full generality, by providing an exact (Green's functions) solution for the field of an off-axis point particle running at constant velocity in a circular pipe with finite wall conductivity and thickness.

* A.W. Chao, Phys. of Collective Beam Instab. in High En. Accel., Wiley,1993** S. Piwinski, DESY 1972/72

 
 
WEPLT094 Electromagnetic Fields of an Off-axis Bunched Beam in a Circular Pipe with Finite Conductivity and Thickness - II impedance, antiproton, vacuum, booster 2068
 
  • S. Petracca, L. Cappetta, T. Demma
    U. Sannio, Benevento
  • R.P. Croce
    Universita' degli Studi di Salerno, Dipartimento di Fisica E.R. Caianiello, Baronissi
  The general exact solution exploited [*] is applied, introducing suitable dimensionless parameters, and using appropriate asymptotic limiting forms, to compute the wake field multipoles for the different paradigm cases of LHC and DAPHNE.

* R. P. Croce, Th. Demma, S. Petracca "Electromagnetic Fields of an Off-axis Bunch in a Circular Pipe with Finite Conductivity and Thickness", these proceedings

 
 
WEPLT095 Modified Polarizabilities and Wall Impedance for Shielded Perforated Beam Pipes with General Shape antiproton, vacuum, booster, target 2071
 
  • S. Petracca, T. Demma
    U. Sannio, Benevento
  We extend previous results [*] concerning the modified polarizability of (electrically small) holes/slots in the wall of a circular beam liner surrounded by a coaxial circular tube to the most general liner and cold bore geometries. We obtain an equivalent wall impedance to describe the electromagnetic boundary conditions at perforated walls for this most general case, and use a general perturbational approach [**] for computing the pertinent longitudinal and transverse coupling impedances.

* R.L. Gluckstern, CERN SL 92-06 (AP), 1992, CERN SL 92-31 (AP), 1992; R.L. Gluckstern, B. Zotter, CERN SL 96-56 (AP), 1996.** S. Petracca, Part. Acc., {\bf 50}, 211, 1995; id., Phys. Rev. E, 60 (3),1999.

 
 
WEPLT097 Beam Loading in the RF Deflector of the CTF3 Delay Loop antiproton, vacuum, booster, target 2074
 
  • D. Alesini, F. Marcellini
    INFN/LNF, Frascati (Roma)
  In this paper we describe the impact of the beam loading in the RF deflectors on the transverse beam dynamics of the CTF3 Delay Loop. The general expression for the single passage wake field is obtained. A dedicated tracking code has been written to study the multi-bunch multi-turn effects on the transverse beam dynamics. A complete analysis for different machine parameters and injection errors is presented and discussed. The numerical simulations show that the beam emittance growth due to the wake field in the RF deflectors is small.  
 
WEPLT098 Experience with Long Term Operation with Demineralized Water Systems at DAFNE antiproton, vacuum, booster, target 2077
 
  • L. Pellegrino
    INFN/LNF, Frascati (Roma)
  During eight years operation of the Dafne water cooling system we coped with several critical situations and managed successfully specific upgrades to the demineralized water system. Here we revise critically the collected data and the experience gained in the field of copper corrosion and related water treatment.  
 
WEPLT100 Planar Electron Sources and the Electron Trap ELTRAP electron, antiproton, plasma, vacuum 2080
 
  • M. Cavenago
    INFN/LNL, Legnaro, Padova
  • G. Bettega, F. Cavaliere, A. Illiberi, R. Pozzoli, M. Romé, L. Serafini
    INFN-Milano, Milano
  Filamentation and other space charge effects (both transverse and longitudinal) of intense electron beams, found for example in rf photoinjectors (beam energy 1 MeV, current 100 A), are easily studied in small voltage traps and drift channels (0.01-10 kV), keeping the same perveance order. A suitable Malmberg-Penning trap, named ELTRAP, installed and operated at the University of Milan, is briefly described; trap length ranges from 10 cm to 1 m; an uniform magnetic field confines electron radially. Several experimental regimes were investigated with the internal CW planar electron source: plasma, beam-plasma, beam, depending on the injection/extraction method chosen. Evolution of electron vortices and virtual cathode formation is documented; analogy with meteorologic and astrophysical plasma is discussed. Upgrading with an external laser pulsed electron source is in course. Larger planar sources are also under construction. (Main classification 4: Beam Dynamics and Electro-magnetic Fields; D03 High Intensity, Incoherent Instabilities, Space Charge, Halos, Cooling; Other classification 8: Low and Intermediate Energy Accelerators and Sources; T12 Beam Injection/Extraction and Transport; T02 Lepton sources)  
 
THPKF028 Upgrade of the Cryomodule Prototype before its Implementation in SOLEIL beamloading, lattice, beamlosses, impedance 2326
 
  • P. Bosland
    CEA/DSM, Gif-sur-Yvette
  • P. Bredy, S. Chel, G. Devanz
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • R. Losito
    CERN, Geneva
  • P. Marchand, K. Tavakoli, C. Thomas-Madec
    SOLEIL, Gif-sur-Yvette
  In the Storage Ring (SR) of the Synchrotron SOLEIL light source, two cryomodules will provide the maximum power of 600 kW required at the nominal energy of 2.75 GeV with the full beam current of 500 mA. A cryomodule prototype, housing two 352 MHz superconducting single-cell cavities with strong damping of the Higher Order Modes has been built and successfully tested in the ESRF storage ring. Even though the achieved performance (3 MV and 380 kW) does meet the SOLEIL requirement for the 1st year of operation, the cryomodule prototype will be upgraded before its installation in the SR early 2005. Modifications will be made on the internal cryogenic system, and also on the power and dipolar HOM couplers. That requires a complete disassembling and reassembling of the cryomodule, which is being carried out at CERN in the framework of collaboration between SOLEIL, CEA and CERN. Additional 3D RF calculations have been performed on the full SOLEIL RF structure in order to get a more detailed description of the dipolar modes damping and of the dipolar HOM couplers tuning. A second cryomodule, similar to the modified prototype, will be built and installed in the SR about one year later.  
 
THPKF029 Femto-second Electron Beam Slicing Project at SOLEIL beamloading, beamlosses, impedance, radiation 2329
 
  • O.V. Chubar, M. Idir, M.-P. Level, A. Loulergue, T. Moreno, A. Nadji, L.S. Nadolski, F. Polack
    SOLEIL, Gif-sur-Yvette
  The goal of the slicing project at SOLEIL is to provide short (50-100 fs) soft and hard X-rays pulses. The principle is based on the technique demonstrated earlier at ALS. In our case, the naturally suitable phase advances and the horizontal distributed dispersion enable the sliced pulse to be used on several consecutive straight sections. Further separation between the core and the sliced electron beams is obtained by increasing the effective horizontal dispersion using a chicane bracketing the modulator. In the hard X-rays case, the photon beams are separated spatially using a simple slit in a pinhole-camera type configuration while a mixed spatial-angular separation is chosen for the soft X-rays case. This minimizes the amount of parasitic core radiation scattered from the surface of the first focusing mirror. We will first describe the proposed scheme, the impact on the machine and some other issues. Then, photon optics calculation is presented. This takes into account the SOLEIL magnet lattice, realistic parameters of a femto-second laser, peculiarities of spectral distributions of undulator radiation and its diffraction in the range of intensities covering several orders of magnitude.  
 
THPKF030 Progress Report on the construction of SOLEIL booster, beamloading, beamlosses, linac 2332
 
  • J.-M. Filhol
    SOLEIL, Gif-sur-Yvette
  The construction of SOLEIL, the French new SR facility, was launched in Jan 2002. The construction of the building has started in Aug 2003 and will enable a progressive beneficial occupancy from summer 2004 onwards. It is foreseen to achieve the commissioning of the 100 MeV Linac by the end of 2004, of the 3 Hz Booster in spring 2005 and of the 2.75 GeV Storage Ring by the end of 2005. All the major components have been ordered and some have already been delivered : the Booster and SR dipole magnets, the Linac sections and the Booster RF cavity. Some innovative development have been initiated specifically for SOLEIL: A 352 MHz SC RF cavity, solid state RF amplifiers for the Booster (40 kW) and the Ring (2 x 190 kW), BPM digital electronics, Al NEG coated vacuum vessels for all straight parts of the ring, or electromagnetic undulators to provide high brilliance polarized light in the VUV range. In order to provide the best performances, significant attention was paid at each design stage (optics, magnets, BPM, vacuum and RF systems,..), involving a large effort of simulation, using 6D tracking codes, or evaluating in detail the contribution of each component to the machine impedance.

on behalf of the SOLEIL project team

 
 
THPKF031 High Power (35 KW and 190 KW) 352 MHZ Solid State Amplifiers for Synchrotron SOLEIL beamloading, beamlosses, linac, vacuum 2335
 
  • P. Marchand, R.L. Lopes, J. Polian, F. Ribeiro, T. Ruan
    SOLEIL, Gif-sur-Yvette
  In the SOLEIL Storage Ring (SR), two cryomodules, each containing a pair of superconducting cavities will provide the maximum power of 600 kW, required at the nominal energy of 2.75 GeV with the full beam current of 500 mA and all the insertion devices. Each of the four cavities will be powered with a 190 kW solid state amplifier consisting in a combination of 315 W elementary modules (about 750 modules per amplifier). The amplifier modules, based on a technology developed in house, with MOSFET transistor, integrated circulator and individual power supply, will be fabricated in the industry. In the booster, a 40 kW solid state amplifier (147 modules) will power a 5-cell copper cavity of the LEP type. The status and the test results of the different parts of the equipment are reported in this paper.  
 
THPKF032 Cleaning of Parastic Bunches in the ESRF Booster Synchrotron for Time Structure Modes of Operation booster, beamloading, beamlosses, linac 2338
 
  • E. Plouviez, N. Michel
    ESRF, Grenoble
  The ESRF injector booster accelerates electron bunches from 200 MeV to 6 GeV and inject them in a storage ring. It can accelerate a small number (1 to 5) of high charge bunches for the so called "time structure" filling mode operation of the SR. In this case we must avoid storing parasitic low charge bunches in the unused RF bucket of the SR. Until now this was achieved by a resonant knockout of these parasitic bunches on the beam stored in the SR. We have developed and implemented a system allowing the removal of these parasitic electrons during the acceleration in the booster, so that no extra cleaning is needed on the beam stored in the SR. This paper describes our setup and its key components, the tuning of the operating parameters of the system and presents the results achieved.  
 
THPKF033 Prospects for Long-term Lattice Upgrade at the ESRF booster, beamloading, beamlosses, linac 2341
 
  • A. Ropert, P. Elleaume, L. Farvacque, Y. Papaphilippou, T. Perron
    ESRF, Grenoble
  Twelve years after commissioning, the ESRF delivers routinely X-rays of brilliance, a factor hundred higher than the design target, to 45 beamlines. Further long-term improvements to the storage ring performance concern the reduction of the horizontal emittance leading to an increase of the brilliance and/or the increase of the number of beamlines from insertion device source points. In this paper, we review the different scenarios that can be envisaged with keeping untouched the existing tunnel and beamlines. Among them, the concept of the Double DBA structure that combines the reduction of emittance (a factor of 8) and the increase of the number of straight sections (64 instead of 32) looks the most attractive. Some of the challenging issues of such a scheme (squeezed space between magnets, innovative combined function magnets of unprecedented small aperture, small dynamic aperture) will be discussed.  
 
THPKF034 Design of a Photoneutron Source based on a 5 MeV Electron Linac target, electron, booster, beamloading 2344
 
  • L. Auditore, R.C. Barnà, D. De Pasquale, A. Trifirò, M. Trimarchi
    INFN & Messina University, S. Agata, Messina
  • A. Italiano
    INFN - Gruppo Messina, S. Agata, Messina
  A photoneutron source, based on a 5 MeV electron linac was designed by means of the MCNP simulation code. Although higher electron energies are required to produce acceptable neutron fluxes, the availability of a 5 MeV electron linac developed at the Dipartimento di Fisica (Università di Messina) has suggested this project, in sight of a future development and testing of the studied neutron source. Be and BeD2 targets were considered, whose neutron production was studied optimizing two sequential steps: the bremsstrahlung production in a suitable e-gamma converter and the (gamma,n) production in an properly designed photoneutron target-reflector-moderator system. As a result of a comparative study of different materials performances, a 0.88 mm-thick W layer was chosen as e-gamma converter. A natural graphite reflector was designed, surrounding the target, enhancing the neutron flux of two order of magnitude. The final neutron flux, at 50 cm from the photoneutron target, thermalized by a 12.2 cm-thick PE layer, was estimated to be 8.48E+07 n/cm2/sec/mA with Be target and 1.23E+08 n/cm2/sec/mA with BeD2 target.  
 
THPKF035 Design of the Super-SOR Light Source target, synchrotron, booster, beamloading 2347
 
  • N. Nakamura
    ISSP/SRL, Chiba
  The Super-SOR light source is a Japanese VUV and soft X-ray third-generation synchrotron radiation source, which is to be operated for nation-wide and world-wide users. The University of Tokyo has proposed to construct the facility in Kashiwa new campus and we have designed the light source intensively for more than two years. The light source consists of an electron storage ring, booster synchrotron and pre-injector linac. The 1.8-GeV storage ring has a circumference of about 280 m and 14 DBA cells with two 17-m and twelve 6.2-m long straight sections, which are used for twelve insertion devices and RF and injection systems. The booster synchrotron is compact, one third of the ring in circumference, and can achieve a low emittance of about 50 nmrad at 1.8 GeV. The 200-MeV linac is made up of S-band accelerating structures powered by two 50-MW klystrons and a SLED cavity and capable of changing the beam current widely in both single- and multi-bunch operation modes. These accelerators are designed so as to fully meet requirements for top-up injection. We describe the design of the Super-SOR accelerators here.

on behalf of the Super-SOR accelerator design group