A   B   C   D   E   F   G   H   I   K   L   M   N   O   P   Q   R   S   T   U   V   W    

undulator

      
Paper Title Other Keywords Page
MOYCH01 The TESLA XFEL Project electron, linac, photon, laser 11
 
  • H. Weise
    DESY, Hamburg
  The overall layout of the X-Ray FEL to be built in international collaboration at DESY will be described. This includes the envisaged operation parameters for the linear accelerator which will use TESLA technology. Main emphasis is put on the specification of the superconducting accelerator modules. Other linac components will be described as well. Work packages needed to finalize the linac design will be presented. A summary of the status of the preparation work will be given.  
Video of talk
Transparencies
 
MOPKF004 Magnet Sorting Algorithm Applied to the LNLS EPU radiation, polarization, wiggler, permanent-magnet 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.  
 
MOPKF008 The BESSY Soft X-ray FEL User Facility photon, simulation, laser, electron 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 bunching, electron, polarization, laser 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 bunching, electron, radiation, simulation 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.  
 
MOPKF020 Proposal for a Sub-100 fs Electron Bunch Arrival-time Monitor for the VUV-FEL at DESY laser, electron, polarization, simulation 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.  
 
MOPKF025 Planar and Planar Helical Superconductive Undulators for Storage Rings, State of the Art vacuum, polarization, storage-ring, synchrotron 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.  
 
MOPKF029 Seeding High Gain Harmonic Generation with Laser Harmonics produced in Gases simulation, electron 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.  
 
MOPKF031 SOLEIL Insertion Devices: The Progress Report insertion, insertion-device, radiation, polarization 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 insertion, insertion-device, photon, radiation 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.  
 
MOPKF034 Status of the Development of Superconducting Undulators at the ESRF storage-ring, vacuum, synchrotron, radiation 378
 
  • E.J. Wallén, J. Chavanne, P. Elleaume
    ESRF, Grenoble
  This note describes the present status of the development of superconducting undulators at the ESRF. Magnetic models of superconducting undulators suitable for the ESRF storage ring have been developed and evaluated. The superconducting undulators studied are horizontally polarizing undulators with a flat field profile and the vertical physical aperture of the undulator is 6 mm. Both 2D models of the local field in a period of the undulator and 3D models of the complete superconducting undulator, including the end sections and current leads, have been evaluated. The practical limit for the obtainable magnetic field has been estimated from the known performance of superconducting wire available from the cabling industry. This note also describes the conceptual design of the cryostat of the superconducting undulator and estimations of the expected heat load to the cryostat at different filling modes of the storage ring.  
 
MOPKF035 Stabilization of the Pulsed Regimes on Storage Ring Free Electron Laser: The Cases of Super-ACO and Elettra laser, feedback, electron, storage-ring 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

 
 
MOPKF036 Wideband Infrared FEL electron, vacuum, laser, simulation 384
 
  • J.-M. Ortega, F. Glotin, R. Prazeres
    LURE, Orsay
  The infrared free-electron laser offers the advantage of a potential large tunability since the FEL gain itself remains subtantially high throughout the infrared spectral range, provided that the electron beam quality remains sufficient at low energy. Moreover, the reflectivity of metal mirrors used in the optical cavity remains close to unity from the near infrared up to the microwave range. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator and other optical cavity elements. The undulator magnetic gap, and thus magnetic chamber inner heigth, cannot be made arbitrarily large since one needs a K parameter sufficiently large to produce a large wavength tunability (typically K > 2). The diffraction losses can however be further reduced by using an elliptical vacuum chamber inside the undulator and elliptical, instead of spherical, mirrors. Then the optical beam is partially guided inside the chamber. Working in this regime at CLIO, we have obtained an FEL tunable from 3 to 120 μm by operating the accelerator between 50 and 14 MeV. This is the largest spectral range ever obtained with a single optical cavity. We plan to use larger mirrors to further reduce the diffraction produced at the edges of the undulator chambers in order to increase the maximum wavelength to approximately 200 μm  
 
MOPKF037 FERMI@ELETTRA: 100 nm - 10 nm Single Pass FEL User Facility linac, electron, radiation, laser 387
 
  • R.J. Bakker, C. Bocchetta, P. Craievich, G. D'Auria, M. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, G. Pangon, L. Rumiz, L. Tosi, V. Verzilov, D. Zangrando
    ELETTRA, Basovizza, Trieste
  The FERMI@ELETTRA project is an initiative from ELETTRA, INFM and other Italian institutes, to construct a single-pass FEL user-facility for the wavelength range from 100 nm (12 eV) to 10 nm (124 eV), to be located next to the third-generation synchrotron radiation facility ELETTRA in Trieste, Italy. The project is concentrated around the existing 1.2-GeV S-band linac, i.e., the injector for the storage ring. Presently the linac is only operational for approximately 2 hours per day. The remaining time is available for the construction and operation of an FEL but modifications and operation must be planned such that operation of the storage ring can be guaranteed until the completion of a new full-energy injector (spring 2006). At this moment the FEL project evolves from a conceptional design stage towards a technical design and the actual implementation. Key issues are: incorporation of the free-electron laser in the infrastructure of the Sincrotrone Trieste, adjustments of the linac to facilitate FEL operation, required additional civil engineering, undulator design, FEL seeding options, and beamline design. This paper serves as an overview of the project in combination with a discussion of the critical issues involved.  
 
MOPKF041 SPARC Photoinjector Working Point Optimization, Tolerances and Sensitivity to Errors emittance, simulation, gun, linac 396
 
  • M. Ferrario, M.E. Biagini, M. Boscolo, V. Fusco, S. Guiducci, M.  Migliorati, C. Sanelli, F. Tazzioli, C. Vaccarezza
    INFN/LNF, Frascati (Roma)
  • L. Giannessi, L. Mezi, M. Quattromini, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • J. Rosenzweig
    UCLA, Los Angeles, California
  • L. Serafini
    INFN-Milano, Milano
  A new optimization of the SPARC photoinjector, aiming to reduce the FEL saturation length, is presented in this paper. Start to end simulations show that with 1.1 nC charge in a 10 ps long bunch we can deliver at the undulator entrance a beam having 100 A in 50% of the slices (each slice being 300 mm long) with a slice emittance ?1 mm, thus reducing the FEL-SASE saturation length to 12 m at 500 nm wavelength. In addition the stability of the nominal working point and its sensitivity to various type of random errors, under realistic conditions of the SPARC photoinjector operation, are discussed. A systematic scan of the main parameters around the operating point, performed with PARMELA code interfaced to MATLAB, shows that the probability to get a projected emittance exceeding 1 mm is only 10 % and the slice emittance remains below 1 mm in all cases.  
 
MOPKF042 Status of the SPARC Project laser, emittance, linac, gun 399
 
  • M. Ferrario, D. Alesini, M. Bellaveglia, S. Bertolucci, M.E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, L. Pellegrino, M.A. Preger, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario
    INFN/LNF, Frascati (Roma)
  • F. Alessandria, A. Bacci, M. Mauri
    INFN/LASA, Segrate (MI)
  • I. Boscolo, F. Brogli, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, M. Romé, L. Serafini
    INFN-Milano, Milano
  • L. Catani, E.C. Chiadroni, A. Cianchi, S. Tazzari
    Università di Roma II Tor Vergata, Roma
  • F. Ciocci, G. Dattoli, A. Doria, F. Flora, G.P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, L. Mezi, P.L. Ottaviani, L. Picardi, M. Quattromini, A. Renieri, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • D. Dowell, P. Emma, C. Limborg-Deprey, D. Palmer
    SLAC, Menlo Park, California
  • D. Levi, M. Mattioli, G. Medici
    Università di Roma I La Sapienza, Roma
  • M.  Migliorati, A. Mostacci, L. Palumbo
    Rome University La Sapienza, Roma
  • P. Musumeci, J. Rosenzweig
    UCLA, Los Angeles, California
  • M. Nisoli, S. Stagira, S. de Silvestri
    Politecnico/Milano, Milano
  The aim of the SPARC project is to promote an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments at 500 nm and higher harmonics generation. It has been proposed by a collaboration among ENEA-INFN-CNR-Universita‘ di Roma Tor Vergata-INFM-ST and funded by the Italian Government with a 3 year time schedule. The machine will be installed at LNF, inside an existing underground bunker. It is comprised of an rf gun driven by a Ti:Sa laser to produce 10-ps flat top pulses on the photocathode, injecting into three SLAC accelerating sections. We foresee conducting investigations on the emittance correction and on the rf compression techniques up to kA level. The SPARC photoinjector can be used also to investigate beam physics issues like surface-roughness-induced wake fields, bunch-length measurements in the sub-ps range, emittance degradation in magnetic compressors due to CSR. We present in this paper the status of the design activities of the injector and of the undulator. The first test on diagnostic prototypes and the first experimental achievements of the flat top laser pulse production are also discussed.  
 
MOPKF048 Injection Beam Loss at the SPring-8 Storage Ring storage-ring, betatron, simulation, injection 417
 
  • M. Takao, T. Ohshima, S. Sasaki, J. Schimizu, K. Soutome, H. Tanaka
    JASRI/SPring-8, Hyogo
  Capture efficiency of injection beam is extremely important for top-up operation because open photon shutter permits the bremsstrahlung from lost particles to be transported to experimental floor. Furthermore, since the SPring-8 storage ring has many in-vacuum insertion devices with narrow gap, the demagnetization by the lost electron bombardment is also serious to the beam injection with gap closing. To clarify the loss mechanism of injected beam at the SPring-8 storage ring, we investigate the loss process under various conditions of the storage ring, and especially measure the dependence of injection loss rate on gaps of insertion devices. Comparing the measurements with simulations, we found that an injected particle with a large horizontal amplitude begins to oscillate in vertical direction through error magnetic field and eventually disappears at the vertical limit. It is also found that the low chromaticity of the storage ring is effective for the reduction of injection beam loss. In this paper, we report the loss mechanism of the injection beam of the SPring-8 storage ring and the possible improvements of the capture efficiency.  
 
MOPKF050 Current Heart-like Wiggler wiggler, radiation, free-electron-laser, plasma 423
 
  • V.I.R. Niculescu, G.R. Anda, F. Scarlat
    INFLPR, Bucharest - Magurele
  • V. Babin
    INOE, Bucharest
  • C. Stancu, A. Tudorache
    Bucharest University, Faculty of Physics, Bucharest-Magurele
  A new wiggler structure for free electron lasers is presented. Current hart-like wiggler produced magnetic fields which were spatially periodic. The current wiggler structure was in the shape of stacks of modified circle wires. The current had alternating directions. The magnetic field components for each wire present a C2 symmetry (for a model with 3 branches). The wiggler transverse cross - section in arbitrary units was given by the following expressions: x = R(d+sin(3j))cos(j) , y = R(d+sin(3j))sin(j) , z = constant, where d and R are the parameters. In cylindrical coordinates the Biot - Savart law was evaluated numerically. The magnetic field aspect was mainly transversal and also easily adjusted with the current . The versatility of this structure permits new geometrical forms and developments in the wiggler and wiggler design .  
 
MOPKF053 Pulsed-wire Method of Field Measurement on Short Elliptically Polarized Undulator radiation, synchrotron, alignment, polarization 428
 
  • T.-C. Fan, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  With two sets of photo illuminator and detector, scientists already have applied pulsed-wire method to measure the magnetic field along two mutually perpendicular directions. Two-dimensional pulsed-wire method is useful for the test of elliptically polarlized undulator (EPU). We tried to use this method to observe the first integral and second integral fields of a short EPU in real time during the polarization tuning. We have taken care more details than the pulsed-wire measurement of planner undulators. The phase difference, the relative field strength along two direction as well as the precise centerline can be achieved.  
 
MOPKF058 Construction of an APPLE-II Type Undulator at Daresbury Laboratory for the SRS vacuum, radiation, insertion-device, coupling 440
 
  • F.E. Hannon, J.A. Clarke, C. Hill, A.A. Muir, D.J. Scott, B.J.A. Shepherd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  A new variable polarisation undulator of the APPLE-II type has been designed and constructed at Daresbury Laboratory. Testing of the 56mm period device has recently started in the new Magnet Test Facility at Daresbury Laboratory. This paper presents the magnetic and mechanical design of the undulator, and the first magnetic measurement results.  
 
MOPKF064 Design Considerations for a Helical Undulator for the Production of Polarised Positrons for TESLA photon, positron, electron, permanent-magnet 458
 
  • D.J. Scott, S.C. Appleton, J.A. Clarke, B. Todd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • E. Baynham, T.W. Bradshaw, S.C. Carr, Y. Ivanyushenkov, J. Rochford
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  An efficient and simple method for the production of positrons, in the necessary quantities, is one of the problems facing proposals for any future e+ e- Linear Collider project. The possibility of colliding polarised beams would also be an advantage. One method to produce a polarised positron beam uses circularly polarised radiation generated by the main electron beam passing through a helical undulator. Design considerations and calculations for two undulators, based on super-conducting and pure permanent magnet technologies, for the TESLA machine, are presented.  
 
MOPKF065 Magnet Block Sorting for Variably Polarising Undulators electron, insertion-device, simulation, insertion 461
 
  • D.J. Scott
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Effective sorting of permanent magnet blocks for undulators can reduce the adverse effects of magnetic in-homogeneities and engineering tolerances on the electron beam. For variably polarising undulators the number of different modes of operation make defining the objective function of a particular permutation more difficult than for a planar device. Factors required in defining a good objective function for a new APPLE-II type helical undulator for the SRS are discussed. These factors include calculating the magnetic field integrals, the particle trajectory and rms optical phase error. The effects of different weighting of these functions in the objective function are also discussed. A comparison of different optimisation techniques, including simulated annealing and Monte Carlo methods is also made.  
 
MOPKF066 Magnetic Design of a Focusing Undulator for ALPHA-X focusing, electron, permanent-magnet, quadrupole 464
 
  • B.J.A. Shepherd, J.A. Clarke
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  ALPHA-X is a four-year project shared between several research groups in the UK to build a laser-plasma accelerator and produce coherent short-wavelength radiation in an FEL. The FEL undulator will be a 1.5m long, 100 period permanent magnet device with a minimum gap of 3.5mm and a peak field of 0.7T. To focus the beam inside the undulator, several schemes were examined. In the scheme that was selected, the magnet blocks are designed so that the pole face is an approximation of a parabola. This focuses the beam horizontally and vertically. The magnetic design of the undulator is complete; design of the support structure is well under way. Test pieces have been built to ensure that the clamping arrangement is strong enough to cope with the magnetic forces involved. The complete undulator will be built in late 2004 at Daresbury Laboratory, and tested on-site in the new magnet test facility.  
 
MOPKF068 Experimental Study of the Stability Margin with Beam Heating in a Short-Period Superconducting Undulator for the APS vacuum, photon, storage-ring, synchrotron 470
 
  • S.H. Kim, C. Doose, R. Kustom, E.R. Moog, K.M. Thompson
    ANL/APS, Argonne, Illinois
  A superconducting undulator with a period of 15 mm is under development at the Advanced Photon Source (APS). The undulator is designed to achieve a peak field on the beam axis of 0.8 T with an 8 mm pole tip gap and an NbTi coilpack current density of 1 kA/mm2. Because of the high current density in the coilpack, the superconducting magnet operates at about 75% of the short sample limit at 4.2K. Additional heat load to the coilpack, mainly due to the image currents and synchrotron radiation from the electron beam in the storage ring, will reduce the stability margin. An experiment was conducted to measure the reduction in the stability margin of the coilpack due to heat load on the beam chamber. The heat load was deposited in a 12-period prototype undulator using thin-film heaters attached to the inner surface of a simulated vacuum chamber. Evaluation of the stability margin based on the experiment and calculations of the beam heating and thermal conduction between the undulator and beam chamber will be discussed.  
 
MOPKF071 Study of Row Phase Dependent Skew Quadrupole Fields in Apple-II type EPUs at the ALS quadrupole, polarization, focusing, lattice 479
 
  • C. Steier, S. Marks, S. Prestemon, D. Robin, R.D. Schlueter, A. Wolski
    LBNL, Berkeley, California
  Since about 5 years, Apple-II type Elliptically Polarizing Undulators (EPU) have been used very successfully at the ALS to generate high brightness photon beams with arbitrary polarization. However, both EPUs installed so far cause significant changes of the vertical beamsize, especially when the row phase is changed to change the polarization of the photons emitted. The effect has been measured in detail and turned out to be caused by a row phase dependent skew quadrupole term in the EPUs. Magnetic measurements revealed the same effect for the third EPU to be installed later this year. All measurements to identify and quantify the effect with beam will be presented, as well as results of magnetic bench measurements and numeric field simulations.  
 
MOPKF074 Harmonic Cascade FEL Designs for LUX laser, electron, radiation, simulation 488
 
  • G. Penn, J.N. Corlett, W. Fawley, M. Reinsch, W. Wan, J.S. Wurtele, A. Zholents
    LBNL, Berkeley, California
  LUX is a proposed facility for ultrafast X-ray science, based on an electron beam accelerated to GeV energies in a recirculating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 190–250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after entering a second, differently tuned undulator. Repeated stages in a cascade yield increasing photon energies up to 1 keV. Most of the undulators in the cascade operate in the low-gain FEL regime. Harmonic cascades have been designed for each pass of the recirculating linac up to a final electron beam energy of 3.1 GeV. For a given cascade, the photon energy can be selected over a wide range by varying the seed laser frequency and the field strength in the undulators. We present simulation results using the codes GENESIS and GINGER, as well as the results of analytical models which predict FEL performance. We discuss lattice considerations pertinent for harmonic cascade FELs, as well as sensitivity studies and requirements on the electron beam.  
 
MOPKF078 ERL Upgrade of an Existing X-ray Facility: CHESS at CESR linac, electron, emittance, optics 497
 
  • G. Hoffstaetter, M. Liepe, R.M. Talman, M. Tigner
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • I. Bazarov, H. Bilderback, M. Billing, S. Gruner, D. Sagan, C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  CORNELL has proposed an Energy-Recovery Linac (ERL) based synchrotron-light facility which can provide improved x-ray radiation due to the high beam quality that can be available from a linac. To additionally utilize beam currents that are competitive with ring-based light sources, the linac has to operate with the novel technique of energy recovery, the feasibility of which CORNELL plans to demonstrate in a downscaled prototype ERL. Here we present an ERL upgrade of the existing 2nd generation light source CHESS at CESR. This proposed upgrade suggests how existing storage rings can be extended to ERL light sources with much improved beam qualities.  
 
MOPKF080 Controlling Emittance Growth in an FEL Beam Conditioner emittance, quadrupole, lattice, electron 503
 
  • P. Emma, G.V. Stupakov
    SLAC, Menlo Park, California
  It has been proposed [*] to 'condition' an electron beam prior to the undulator of a Free-Electron Laser (FEL) by increasing each particle's energy in proportion to the square of its transverse betatron amplitude. This conditioning enhances FEL gain by reducing the axial velocity spread within the electron bunch. Previosly [**] we presented a system that allows conditioning of the beam on a relatively short distance, however, it suffers from projected beam emittance growth to the extent that makes it impractical for application for X-ray FELs. In this paper we extend analysis proposed by A. Wolski for general requirements to the conditioner which does not have such emittance growth. We also present a possible implementation of a beam conditioner consisting of multiple solenoid cells in combination with quadrupole magnets. Simulations show that in such a system the emittance growth can be suppressed to acceptable level, albeit in a longer system.

* A. Sessler et al., Phys. Rev. Lett., 68, 309 (1992).** P. Emma and G. Stupakov. PRSTAB, 6, 030701 (2003).

 
 
MOPKF081 Peak Current Optimization for LCLS Bunch Compressor 2 emittance, simulation, damping, linac 506
 
  • A.C. Kabel, P. Emma
    SLAC, Menlo Park, California
  The performance of an FEL will be a function of both the driving bunch's current and its slice emittance. We have studied a set of parameters for the bunch compression section of the LCLS, simulating the effects of Coherent Synchrotron Radiation (CSR) on the slice emittance of the bunch core as a function of peak current. We use the code TraFiC4 for a three-dimensional, self-consistent simulation on parallel computers. While higher currents will increase FEL performance, its detrimental effects, due to CSR, on slice emittance will counteract this beneficial effect. From our simulations, we determine a near-optimum current, balancing these effects.  
 
MOPKF083 Inverse Free Electron Laser Heater for the LCLS laser, electron, linac, gun 512
 
  • R. Carr, L.D. Bentson, P. Bolton, D. Dowell, P. Emma, A. Gilevich, Z. Huang, J.J. Welch, J. Wu
    SLAC, Menlo Park, California
  The LCLS Free Electron Laser employs an RF photocathode gun that yields a 1 nC charge bunch a few picoseconds long, which must be further compressed to yield the high current required for SASE gain. The very cold electron beam from the RF photocathode gun is quite sensitive to microbunching instabilities such as coherent synchrotron radiation (CSR) in the compressor chicanes and longitudinal space charge (LSC) in the linac. These effects can be Landau damped by adding energy spread to the electron bunch prior to compression. We propose to do this by interacting an infrared laser beam with the electron bunch in an undulator added to the LCLS gun-to-linac injector. The undulator is placed in a 4-bend chicane to allow the IR laser beam to propagate co-linearly with the e-beam while it oscillates in the undulator. The IR laser beam is derived from the photocathode gun laser. Simulations presented elsewhere in these proceedings show that the laser interaction damps the microbunching instabilities to a very great extent. This paper is a description of the implementation of the laser heater  
 
MOPLT027 Cold Beam Vacuum Interconnects for the LHC Insertion Regions vacuum, impedance, insertion, synchrotron 599
 
  • D.R. Ramos, D. Chauville, J. Knaster, R. Veness
    CERN, Geneva
  The LHC machine is composed of arcs and insertion regions where superconducting magnets, working at temperatures of 1.9 K and 4.5 K, have flexibly interconnected beam vacuum chambers. These interconnects must respect strict requirements in terms of impedance, aperture, space optimization and reliability. A complete interconnect design was first developed for the arc regions, and from which a total of 20 variants have been created according to the different functional requirements of each pair of cryostats along the machine. All design features and manufacture processes were validated through extensive testing. Manufacture and assembly cost was minimised by using a modular interconnect design, with common components shared among different design variants. A detailed quality assurance structure was implemented in order to achieve the high level of reliability required. This paper presents the layout of cold beam vacuum interconnects along with details of development and testing performed to validate design and integration.  
 
MOPLT081 Low Energy Ion Beam Dynamics in Axisymmetric RF Undulator Linac focusing, linac, ion, acceleration 731
 
  • E.S. Masunov, S.M. Polozov
    MEPhI, Moscow
  The ion beam focusing and acceleration in an axisymmetric periodic RF undulator structure is considered. There is suggested that RF field has no a synchronous wave and accelerating force is to be driven by a combination of two non-synchronous waves. The influence of non-synchronous harmonics on ion beam dynamics is studied by means of a smooth approximation. Choice and optimization of RF field harmonics are made to obtain maximal transmission coefficient. The result is verified by a numerical simulation. The comparison with a conventional RF linac, where a synchronous harmonic accelerates a beam and non-synchronous one is focusing a beam, is described. This comparison is suitable for demonstration of the capabilities of an undulator linac.  
 
TUYBCH01 Design Criteria and Technology Challenges for the Undulators of the Future radiation, electron, synchrotron, vacuum 59
 
  • H. Kitamura, T. Hara, X. Maréchal, T. Tanaka
    RIKEN Spring-8 Harima, Hyogo
  • T. Bizen, T. Seike
    JASRI/SPring-8, Hyogo
  Nowadays, undulators are essential devices for synchrotron radiation (SR) facilities since they generate a quasi-monochromatic radiation with various features, high brightness , high energy and special polarization characteristics. Particularly, demands for high-energy radiation in the X-ray region have become much stronger in many research fields. Accordingly, a short-period undulator design has been developed, because they increase the number of periods in a unit undulator length and as a consequence, they generate brilliant synchrotron radiation. Also, short undulator periodicity enables emission of high-energy photons, and it opens the way for X-ray beamline operation in medium size synchrotron radiation facilities, such as SLS, NSLS, PLS, CLS, ALS, SOLEIL, DIAMOND, SPEAR-III and so on. From the same reason, a short-period undulator is very attractive for SASE-FEL or ERL facilities, since it lowers the electron beam energy necessary for X-ray operation. As a result this design makes a whole facility design compact and economic. In the talk, I will review the status of the development on short-period undulators of various types (in-vacuum, superconducting and cryogenic types) and describe the future direction.  
Video of talk
Transparencies
 
TUPKF038 Reduced Length Designs of 500 MHz Damped Cavity Using SiC Microwave Absorber storage-ring, impedance, synchrotron, factory 1048
 
  • T. Koseki
    RIKEN/RARF/BPEL, Saitama
  • M. Izawa, S. Sakanaka, T. Takahashi, K. Umemori
    KEK, Ibaraki
  We present a new 500 MHz HOM (Higher-Order Modes) damped cavity for high brilliance synchrotron radiation sources. The design is based on the damped cavity, which is operated at the Photon Factory storage ring in KEK. The PF cavity has a large hole beam duct (140 mm in diameter), a part of which is made of a silicon carbide (SiC) microwave absorber. The new cavity, proposed in this paper, has parallel-plate radial transmission lines on the beam duct instead of the SiC beam duct. The outer end of the radial line is terminated by SiC absorbers. The HOMs, extracted from the center part of the cavity through the beam duct, propagate in the radial line and are dissipated in the absorber. The accelerating mode is not affected by the radial line damper since the frequency is sufficiently below the cutoff of the 140-mm beam duct. In this paper, optimized design of the radial line damper and damping properties for HOMs are described in detail.  
 
TUPLT002 The Small-gap Undulator Impedance Study impedance, vacuum, resonance, synchrotron 1132
 
  • M. Ivanyan, V.M. Tsakanov
    CANDLE, Yerevan
  The small gap undulator vacuum chamber resistive impedance model is developed. The vacuum chamber is considered as equal-radii tubes with the different wall materials (stainless steel "copper" stainless steel). The complete impedance was calculated as a sum of tubes and transitions impedances. The modal expansion method for transition impedance calculation is presented.  
 
TUPLT095 Precision Field Mapping System for Cyclotron Magnet cyclotron, alignment, insertion, insertion-device 1378
 
  • K.-H. Park, Y.G. Jung, D.E. Kim, L.W.W. Lee
    PAL, Pohang
  • J.-S. Chai, Y.S. Kim
    KIRAMS, Seoul
  • B.-K. Kang, S.H. Shin, M. Yoon
    POSTECH, Pohang
  A 13 MeV cyclotron has been developed by KIRAMS for radio-isotopes production such as F-18 and O-15 for positron emission tomography(PET). To characterize the cyclotron magnet precisely, a Hall probe mapping system with very high precise positioning mechanism in the Cartesian coordinate has been developed. Hall probe assembly was translated in two dimensions by two stepping motors at both sides of the Hall-probe-carrier to keep synchronously rotation sharing one step-pulse source for x-axis and one motor for y-axis. The data acquisition time had reduced to 60 minutes in full mapping by 'flying' mode. The accuracy of the measurement system is better than during the entire mapping process. In this paper the magnetic field measurement system for the cyclotron magnet is described, and measurement results are presented.  
 
WEYLH01 Emittance Control for Very Short Bunches linac, emittance, impedance, simulation 179
 
  • K.L.F. Bane
    SLAC, Menlo Park, California
  Many recent accelerator projects call for the production of high energy bunches of electrons or positrons that are simultaneously short, intense, and have small emittances. Two examples of such projects are linear colliders, such as the GLC/NLC, and Self-Amplified Spontaneous Emission (SASE) FEL's, such as the Linac Coherent Light Source (LCLS). A major challenge in such projects is keeping in check forces that increase short bunch emittances in accelerator components, such as: wakefields of accelerator structures, collimators, and surface roughness, and coherent synchrotron radiation (CSR). We describe such forces and their control.  
Video of talk
Transparencies
 
WEPKF017 The 5 T Superconducting Undulator for the LHC Synchrotron Radiation Profile Monitor synchrotron, radiation, synchrotron-radiation, proton 1630
 
  • R. Maccaferri, M. Facchini, R. Jung, D. Tommasini, W.  Venturini Delsolaro
    CERN, Geneva
  A Synchrotron Radiation Profile Monitor will be used in the LHC to measure the beam profiles from the injection energy of 450 GeV to the nominal energy of 7 TeV. The radiation will be provided by a sequence of two separate magnets: a two-periods 5 T superconducting undulator and the beam separation dipole D3. After a short description of the profile monitor layout, the paper reviews the electromagnetic and mechanical design of the undulator, and reports on the fabrication and cold test results of a first half period prototype.Finally, for the LHC operation with lead ion beams,a proposal for a monitor sensitivity upgrade by using a 12 T. superconducting undulator is presented and discussed.  
 
WEPKF033 Application of Finite Volume Integral Approach to Computing of 3D Magnetic Fields Created by Distributed Iron-dominated Electromagnet Structures dipole, insertion-device, insertion, permanent-magnet 1675
 
  • O.V. Chubar, C. Benabderrahmane, O. Marcouillé, F. Marteau
    SOLEIL, Gif-sur-Yvette
  • J. Chavanne, P. Elleaume
    ESRF, Grenoble
  Iron-dominated electromagnet structures are traditionally considered as a domain of applications of the Finite-Element Method (FEM). FEM computer codes provide high accuracy for "close circuit" type geometries, however they are much less efficient for distributed geometries consisting of many spatially separated magnets interacting with each other. Examples of such geometries related to particle accelerators are insertion devices, quadrupole and sextupole magnets located close to each other, magnets with combined functions. Application of the finite volume integral approach implemented in the Radia 3D magnetostatics code to solving such geometries is described. In this approach, space around individual magnets does not require any meshing. An adaptive segmentation of iron parts, with the segmenting planes being roughly perpendicular or parallel to the expected directions of magnetic flux lines, minimizes dramatically the necessary CPU and memory resources. If a geometry is, nevertheless, too big for its complete interaction matrix to fit into memory, a special scheme of relaxation "by parts" can be applied. The results of calculations made for the SOLEIL electromagnet undulator HU256 will be presented.  
 
WEPKF053 Status and Development for the JAERI ERL-FEL for High-Power and Long-Pulse Operation coupling, linac, pick-up, feedback 1723
 
  • M. Sawamura, R. Hajima, N. Kikuzawa, E.J. Minehara, R. Nagai, N. Nishimori
    JAERI/FEL, Ibaraki-ken
  After the success of energy recovery linac (ERL) for the superconducting free-electron laser (FEL) in the Japan Atomic Energy Research Institute (JAERI), the JAERI ERL-FEL has been upgrading for high-power and long-pulse operation. The new grid pulser for the thermoionic cathode gun is under development and test to increase the beam current by increasing the repetition rate of 10MHz to 20MHz. The new RF sources of CW mode for higher power for non-energy-recovery parts have been installed and tested for long-pulse operation. The properties of the superconducting linac required for the long-pulse operation were also measured such as pressure in the cryomodule, vibration of frequency and piezo tuner response. The RF control systems have been also upgraded to reduce the fluctuation to less than 0.1% for amplitude and 0.1 deg for phase.  
 
WEPLT066 Beam Dynamics Study for PETRA III Including Damping Wigglers wiggler, damping, lattice, dynamic-aperture 1999
 
  • 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.  
 
WEPLT079 Non Linear Beam Dynamics and Lifetime on the SOLEIL Storage Ring resonance, insertion, insertion-device, focusing 2035
 
  • 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.  
 
WEPLT082 General Performances of the Injection Scheme into the SOLEIL Storage Ring injection, septum, coupling, quadrupole 2044
 
  • 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.  
 
WEPLT103 Radiation Damage in Magnets for Undulators at Low Temperature radiation, electron, permanent-magnet, linac 2092
 
  • T. Bizen, X. Maréchal, T. Seike
    JASRI/SPring-8, Hyogo
  • Y. Asano
    JAERI/SPring-8, Hyogo
  • T. Hara, H. Kitamura, T. Tanaka
    RIKEN Spring-8 Harima, Hyogo
  • D.E. Kim, H.S. Lee
    PAL, Pohang
  Nd2Fe14B permanent magnets are used in many insertion devices for its good magnetic and mechanical properties. However, the radiation sensitivity of the magnets would be concern when they are used in a strong radiation environment. It is known that these magnets with very high coercivity show high resistance to radiation, though the substance for increasing the coercivity decrease the remanence. The coercivity and remanence of this magnet exhibit negative dependence against temperature, so it is expected to these magnets to show high remanence and high resistance to radiation at low temperature. The idea of using magnets at low temperature leads the new concept of the cryogenic undulators. In this report, the experimental results of the radiation damage of permanent magnets at low temperature are shown.  
 
WEPLT156 Suppression of Microbunching Instability in the Linac Coherent Light Source laser, electron, linac, simulation 2206
 
  • Z. Huang, P. Emma, C. Limborg-Deprey, G.V. Stupakov, J.J. Welch, J. Wu
    SLAC, Menlo Park, California
  • M. Borland
    ANL/APS, Argonne, Illinois
  A microbunching instability driven by longitudinal space charge, coherent synchrotron radiation and linac wakefields is studied for the linac coherent light source (LCLS) accelerator system. Since the uncorrelated (local) energy spread of electron beams generated from a photocathode rf gun is very small, the microbunching gain may be large enough to significantly amplify shot noise fluctuations of the electron beam. The uncorrelated energy spread can be increased by an order of magnitude without degrading the free-electron laser performance to provide strong Landau damping against the instability. We study different damping options in the LCLS and discuss an effective laser heater to minimize the impacts of the instability on the quality of the electron beam.  
 
THPKF013 Terahertz Diagnostics for the Femtosecond X-ray Source at BESSY laser, electron, radiation, dipole 2284
 
  • K. Holldack, S. Khan, R. Mitzner, T. Quast, G. Wustefeld
    BESSY GmbH, Berlin
  A longitudinal electron density modulation caused by femtoslicing in a storage ring is accompanied by a strong broad band coherent THz-light emission between 0.3 and 10 THz at certain synchrotron radiation emitting devices downstream of the interaction region. A technique to use the THz signal for the control of the overlap of laser and electron bunch using fast infrared bolometers is described. A new dedicated THz extraction port at a bending magnet as well as a spectroscopic setup based on a Martin Puplett spectrometer will be commissioned in May 2004 together with the new femtoslicing source at BESSY.

* A. Zholentz, M. Zoloterev, PRL 76/1996, 912** H.-J. Baecker et al., these proceedings

 
 
THPKF019 PETRA III: A New High Brilliance Synchrotron Radiation Source at DESY wiggler, damping, emittance, insertion 2302
 
  • K. Balewski, W. Brefeld, W. Decking, Y.L. Li, G.K. Sahoo, R. Wanzenberg
    DESY, Hamburg
  DESY has decided to rebuild its 2304 m long accelerator PETRA II into a dedicated light source called PETRA III. The reconstruction is planned to start mid of 2007.The new light source will operate at an energy of 6 GeV, a current of 100 mA, a horizontal emittance of 1 nmrad and an emittance coupling of 1%. In the first phase thirteen insertion devices are foreseen. In this paper the principle layout of the machine will be presented. The structure of the new machine combines properties of conventional storage rings and light sources and is therefore quite unconventional. One of the major challenges of the project is to achieve the small emittances. The basic idea is to use so called damping wigglers with a total length of 80 m to reduce the horizontal emittance to the desired level. To obtain and maintain the small emittances imposes tight tolerances on spurious dispersion and orbit quality and stability. These limits will be given and discussed.  
 
THPKF027 A Concept for the Spanish Light Source CELLS lattice, booster, insertion, insertion-device 2326
 
  • D. Einfeld, J. Bordas, J. Campmany, S. Ferrer, M. Muñoz, M. Pont, F. Pérez
    CELLS, Bellaterra (Cerdanyola del Vallès)
  In May of 2003 the Spanish and Catalan Governments established a public Consortium for the construction, equipment and exploitation of a third generation Synchrotron Light Source. The foundation was based upon a proposal from 1997 to build a 2.5 GeV, 12-fold symmetry machine with a circumference of around 260 m. At present a re-design is being considered, based upon the following decisions: 1.) Electron energy of 3 GeV, 2.) Circumference around 280 m, 3.) Emittance smaller than 5 nm.rad, 4.) 16-fold symmetry lattice 5.) Full energy injector, 6.) Topping-up injection mode foreseen and 7.) Booster synchrotron and Storage ring housed in the same tunnel. Lattice considerations are given in an accompanying paper. In the present one we will give a project overview and explain key design decisions and overall schedule. Five beamlines will be design and construct in a first phase to cover the needs of the Spanish community. The definition of these beamlines will take place during 2004 involving the users community. Planned beam commissioning will be in 2009.  
 
THPKF029 Femto-second Electron Beam Slicing Project at SOLEIL electron, laser, photon, separation-scheme 2332
 
  • 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.  
 
THPKF041 SSRF: A 3.5GeV Synchrotron Light Source for China storage-ring, injection, booster, synchrotron 2368
 
  • Z. Zhao, H. Xu
    SINR, Jiading, Shanghai
  The Shanghai Synchrotron Radiation Facility (SSRF) is an intermediate energy light source that will be built at Zhang-Jiang Hi-Tech Park in Shanghai. The SSRF consists of a 432 m circumference storage ring with an operating energy of 3.5GeV and a minimum emittace of 2.95 nm-rad, a full energy bosster, a 100MeV electron Linac and dozens of beamlines and experimental stations. The design of the SSRF accelerator complex evolves timely along the technological progress such as top-up injection, mini-gap undulator, superconducting RF system and etc. This paper reports the design progress and status of the SSRF project.  
 
THPKF056 The MAX IV Facility linac, emittance, lattice, radiation 2392
 
  • M. Eriksson, Å. Andersson, M. Bergqvist, M. Brandin, M. Demirkan, G. Georgsson, G. LeBlanc, L.-J. Lindgren, L. Malmgren, H. Tarawneh, E.J. Wallén, S. Werin
    MAX-lab, Lund
  • B. Anderberg
    AMACC, Uppsala
  • S. Biedron, S.V. Milton
    ANL, Argonne, Illinois
  The MAX IV facility is a planned successor of the existing MAX facility. The planned facilty is described below. It consists of two new synchrotron storage rings operated at different electron energies to cover a broad spectral region and one linac injector. The linac injector is also meant to be operated as a FEL electron source. The two rings have similar low emittance lattices and are placed on top of each other to save space. A third UV light source, MAX III, is planned to be transfered to the new facility.  
 
THPKF066 Conception of X-ray Source Based on Compact Wakefield Undulator radiation, photon, electron, RF-structure 2415
 
  • A. Opanasenko
    NSC/KIPT, Kharkov
  Study of interaction of bunched charged ultrarelativistic particles with own wakefields in periodic rf structures detects new applications in the area of accelerator physics and technology. Conception of monochromatic X-ray source based on wakefield undulator, WFU, with very short period is presented. In the base of photon generation by the WFU lies a new mechanism of undulator-type radiation emitted by an ultrarelativistic electron bunch that undulates due to non-synchronous spatial harmonics of its wakefields while the bunch moves along a periodic waveguide. The features of the hard radiation and yield of photons depending on waveguide sizes and charge distribution are considered. The creation of the WFU with sub-millimetre periods due to advanced accelerator technology, such as deep X-ray lithography, opens possibilities to obtain high brightness X-rays at employing comparatively low electron energies without external alternative fields. That can have commercial significance for technological and medical applications.  
 
THPKF075 LUX - A Recirculating Linac-based Facility for Ultrafast X-ray Science linac, electron, laser, radiation 2439
 
  • J.N. Corlett, W.A. Barletta, S. De Santis, L.R. Doolittle, W. Fawley, P.A. Heimann, S.R. Leone, D. Li, S.M. Lidia, G. Penn, A. Ratti, M. Reinsch, R.W. Schoenlein, J.W.  Staples, G.D. Stover, S.P. Virostek, W. Wan, R. Wells, R.B. Wilcox, A. Wolski, J.S. Wurtele, A. Zholents
    LBNL, Berkeley, California
  We present design concepts for LUX - a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux VUV-x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1 - 10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and to propagate electron beams carrying nm-scale density modulation in the final stages of cascaded harmonic generation. Synchronization of tens of femtoseconds is achieved by use of an optical master oscillator distributing timing signals over actively stabilized fiber, and generation of rf signals from the optical master oscillator. We describe technical developments in key areas including injection from a high repetition rate rf photocathode gun, lattice design, UV and soft x-ray production by high-gain harmonic generation, a kicker design for rapid transfer of the electron beam between radiator beamlines, lasers systems concepts, and synchronization between experimental pump lasers and the x-ray pulse.  
 
THPKF077 A Fiber Optic Synchronization System for LUX laser, feedback, controls, linac 2445
 
  • R.B. Wilcox, L.R. Doolittle, J.W.  Staples
    LBNL, Berkeley, California
  The proposed LUX femtotsecond light source will support pump-probe experiments that will need to synchronize laser light pulses with electron-beam-generated X-ray pulses to less than 50fs at the experimenter endstations. To synchronize multiple endstation lasers with the X-ray pulse, we are developing a fiber-distributed optical timing network. A high stability clock signal from a modelocked laser is distributed via fiber to RF cavities (controlling X-ray probe pulse timing) and modelocked lasers at endstations (controlling pump pulse timing). The superconducting cavities are actively locked to the optical clock phase. Most of the RF timing error is contained within a 10kHz bandwidth, so these errors and any others affecting X-ray pulse timing (such as RF gun phase) can be detected and transmitted digitally to correct laser timing at the endstations. The lasers? timing jitter is limited to low frequency, and thus they will follow the controls (clock plus error correction) without adding much wideband error. Time delay through the fibers will be stabilized by comparing a retroreflected pulse from the experimenter endstation end with a reference pulse from the sending end, and actively controlling the fiber length. Numerical simulations and initial synchronization experimental results will be presented.  
 
THPLT023 The Use of Photon Monitors at the Swiss Light Source photon, feedback, insertion, insertion-device 2520
 
  • J. Krempasky, M. Böge, T. Schilcher, V. Schlott, T. Schmidt
    PSI, Villigen
  The photon beam position monitors (PBPM) in a synchrotron radiation facility are important tools for beam-line and machine diagnostics since they deliver position and angle information directly from the radiation source point. In the last two years a number of PBPMs have been installed and commissioned at the Swiss Light Source (SLS). Their readouts have been systematically studied and the results have been correlated with data from the digital beam position monitor (DBPM) system. It turns out that the PBPMs help understanding the influence of insertion device gap changes on photon beam position and thus on photon flux and/or energy resolution near the beam-line experimental stations. In addition to the global fast orbit feedback (FOFB), a local slow feedback based on PBPM data has been implemented to remove the remaining systematic effects of the DBPM system and to stabilize the photon beam to a micron level at the experimental station.  
 
THPLT044 Measurement of the Transverse Coherence of the TTF Free Electron Laser electron, radiation, free-electron-laser, laser 2580
 
  • R. Ischebeck, M. Tonutti
    RWTH, Aachen
  • J. Feldhaus, E. Saldin, E. Schneidmiller, K. Tiedtke, R. Treusch
    DESY, Hamburg
  • C. Gerth
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • P. Schmüser
    Uni HH, Hamburg
  • M.V. Yurkov
    JINR, Dubna, Moscow Region
  The transverse coherence is important for many applications of a free electron laser (FEL). It depends on the inner structure of the electron bunch in the undulator, which is difficult to measure. It is therefore essential to determine the coherence properties of the FEL radiation directly. The coherence of the vacuum ultraviolet FEL at the TESLA Test Facility has been measured by recording the diffraction pattern of a double slit and measuring the visibility of the interference fringes. The experimental near field diffraction pattern is compared with a numerical model, taking into account the formation of the FEL radiation, the Fresnel diffraction in the near field zone and effects of the experimental set-up. Diffraction patterns have been recorded at various undulator lengths to measure the evolution of the transverse coherence along the undulator. This is compared to the expected evolution of the transverse radiation modes.  
 
THPLT086 High Temporal Resolution, Single-shot Electron Bunch-length Measurements electron, laser, coupling, monitoring 2700
 
  • G. Berden, B. Redlich, A.F.G. Van der Meer
    FOM Rijnhuizen, Nieuwegein
  • W.A. Gillespie, A. MacLeod
    UAD, Dundee
  • S.P. Jamison
    Strathclyde University, Glasgow
  A new technique, combining the electro-optic detection of the Coulomb field of an electron bunch and the single-shot cross-correlation of optical pulses, is used to provide single-shot measurements of the shape and length of sub-picosecond electron bunches. As in our previous technique [I. Wilke et al., Phys. Rev. Lett. 88, 124801 (2002)], the electric field of the electron beam is encoded electro-optically on an optical pulse. Our earlier measurements, which involved encoding the time profile of the electron bunch on the spectrum of the optical pulse, showed electric field profiles with a FWHM of the order of 1.7 ps. The new method offers a much better time resolution since it avoids the significant measurement artifacts that can arise in our previous (spectral encoding technique due to the coupling between the temporal envelope and spectral content of the optical pulse. The cross-correlation technique has been applied to the measurement of electron bunches in FELIX, showing single bunches of around 500fs FWHM. The resolution is limited primarily by the electro-optic crystal thickness and the relatively low energy of the electrons (50 MeV).