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Paper Title Other Keywords Page
MOZBPA01 Results from the VUV-FEL electron, FEL, undulator, laser 34
 
  • J. Rossbach
    DESY, Hamburg
  The talk will provide the latest results from the VUV-FEL. It will cover the general performance of the machine and comparison to theory. A status will be given of the performance of key systems: the gun, accelerating modules and RF systems, electron and photon beam diagnostics, timing and synchronization and undulator performance. Future developments and implementations will also be discussed (and implications to the XFEL).  
slides icon Transparencies
 
MOPCH002 Seeding the FEL of the SCSS Phase 1 Facility with the 13th Laser Harmonic of a Ti: Sa Laser Produced in Gas laser, FEL, undulator, SASE 44
 
  • G. Lambert, M. Bougeard, W. Boutu, P. Breger, B. Carré, D. Garzella, M. Labat, H. Merdji, P. Monchicourt, P. Salieres
    CEA, Gif-sur-Yvette
  • O.V. Chubar, M.-E. Couprie
    SOLEIL, Gif-sur-Yvette
  • T. Hara, H. Kitamura, T. Shintake
    RIKEN Spring-8 Harima, Hyogo
  • D. Nutarelli
    LAC, Orsay
  A seeding configuration, in which the 13th harmonic (60 nm) of a Ti: Sa laser (50 mJ, 10 Hz, 130 fs) generated in a gas cell is used as the external source, will be tested in 2006 on the SCSS test facility (SPring-8 Compact Sase Source, Japan). This facility is based on a thermionic cathode electron gun (1 nC of bunch charge), a C-band LINAC (5712 MHz, 35 MV/m) and two in-vacuum undulators (15 mm of period). The maximum electron beam energy is 250 MeV and the SASE emission from visible to 60 nm can be obtained. The High order Harmonic Generation (HHG) experiment was mounted off-line at the end of last December. A first chamber is dedicated to harmonic generation. A second one is used for spectral selection and adaptation of the harmonic waist in the modulator. The tests are performed in Saclay with the LUCA (Laser Ultra Court Accordable) laser (15 mJ, 10 Hz, 50 fs) from January to March at 266 nm, 160 nm and 60 nm and its results are presented here. Also, before performing the real tests in SPring-8 FEL presence, final theoretical estimations of the performances relying on 1D simulations using PERSEO code and 3D simulations using GENESIS and SRW codes are given.  
 
MOPCH003 Seeding SPARC Facility with Harmonic Generation in Gases: Preliminary Tests of the Harmonic Generation in Gas Chamber laser, undulator, FEL, electron 47
 
  • O. Tcherbakoff, M. Bougeard, P. Breger, B. Carré, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Monchicourt, P. Salieres
    CEA, Gif-sur-Yvette
  • M.-E. Couprie
    SOLEIL, Gif-sur-Yvette
  • A. Doria, L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma)
  In High Gain Harmonic Generation Free Electron Laser configuration, an external light source is injected in the first part of an undulator. The electron-photon interaction leads to a coherent light emission in the second part of the undulator. We propose to use the High Order Harmonic Generation in gases process as the seed for SPARC project (Frascati, Italy). With this facility, the electron beam is accelerated to 200 MeV and passes through an undulator of 6 sections. The preliminary tests on the seeding chambers presented in this paper have been realised at the CEA (Saclay, France). The experiment is based on three vacuum chambers. In the first one, a Ti: Sa laser (800 nm, 2.5 mJ, 50 fs, 10 Hz) is focussed in a 10 Hz pulsed gas jet (Argon or Xenon), producing harmonics of the fundamental. Filters in the second chamber enable the selection of the harmonic (3rd or 5th). Finally, a telescope focuses the harmonic beam at a given position. The whole module is to be moved to the SPARC facility. Appropriate tuning of the undulator gaps will amplify the 3rd and 5th harmonics seeded, as well as non-linear harmonics of those wavelengths, allowing the perspective of producing a FEL at 53 nm  
 
MOPCH005 The ARC-EN-CIEL FEL Proposal emittance, laser, undulator, FEL 53
 
  • M.-E. Couprie, C. Bruni, O.V. Chubar, A. Loulergue, L. Nahon
    SOLEIL, Gif-sur-Yvette
  • B. Carré, D. Garzella, M. Jablonka, M. Labat, G. Lambert, F. Meot, P. Monot, A. Mosnier
    CEA, Gif-sur-Yvette
  • J.-R. Marquès
    LULI, Palaiseaux
  • D. Nutarelli
    LAC, Orsay
  • J.-M. Ortega
    CLIO/ELYSE/LCP, Orsay
  ARC-EN-CIEL (Accelerator-Radiation Complex for Enhanced Coherent Intense Extended Light), the French project of a fourth generation light source aims at providing the user community with coherent femtosecond light pulses covering from UV to soft X ray. It is based on a CW 1 GeV superconducting linear accelerator delivering high charge, subpicosecond, low emittance electron bunches with a high repetition rate (1 kHz). Electron beam calculations will be presented. The FEL is based on the injection of High Harmonics Generated in Gases (HHG) in a High Gain Harmonic Generation scheme, leading to a rather compact solution. The produced radiation extending down to 0.8 nm with the Non Linear Harmonics reproduces the good longitudinal and transverse coherence of the harmonics in gas. Calculations are preformed with PERSEO, taking into account the proper transverse overlap between HHG and the electron beam, and with SRW. Optional beam loops are foreseen to increase the beam current or the energy. They will accommodate fs synchrotron infrared Coherent Synchrotron Radiation sources, VUV and X ray ranges and a FEL oscillator in the 10 nm range. An important synergy is expected between accelerat  
 
MOPCH007 Undulators for a Seeded HGHG-FEL Test Bench at MAX-lab undulator, electron, FEL, laser 59
 
  • J. Bahrdt, H.-J. Baecker, W.F. Frentrup, A. Gaupp, K. Goldammer, A. Meseck, M. Scheer
    BESSY GmbH, Berlin
  • S. Werin
    MAX-lab, Lund
  Undulators for a Seeded HGHG-FEL at MAX-lab Within the European FEL Design Study a seeded HGHG-FEL will be set up at MAX-lab. In the modulator, a planar pure permanent magnet undulator, the 3rd harmonic of a Ti:Sapphire laser (267nm) interacts with the electron beam. In the following dispersive section the energy modulation is converted into a spatial modulation. The radiator emits at the third harmonic (89nm). The radiator has an APPLE II type magnetic structure providing full polarization control. The undulators and the dispersive section are currently built at BESSY. The electron beam height at MAX-lab of 400mm requires a specific design of the undulator carriages. The magnetic and mechanical design of the HGHG stage will be presented.  
 
MOPCH009 The BESSY 2nd Generation Soft X-ray FEL User Facility FEL, undulator, laser, controls 65
 
  • J. Knobloch
    BESSY GmbH, Berlin
  Future VUV-to-soft-X-ray FEL facilities promise to open fundamentally new frontiers for the synchrotron user community. So-called 2nd generation FELs, which use seeded schemes rather than SASE, can deliver reproducible ultra-short photon pulses at an energy level of mJ/pulse. BESSY has been designing a High-Gain-Harmonic-Generation (HGHG) based FEL with a 2.3 GeV superconducting driver linac that covers photon energies from 24 eV to 1 keV. The design provides full tuneability of photon energy, variable beam polarization and complete synchronization to external lasers—all essential for future femtosecond, time-resolved pump-probe experiments. Also, the CW linac offers great flexibility for the repetition rates and pulse patterns. BESSY-organized User Workshops helped identify the user requirements for such an FEL. This information provided the basis for the Technical Design Report that was submitted to the German Wissenschaftsrat in 2004, which then held an on-site review in 2005. Meanwhile, preparatory studies continue at BESSY. They include start-to-end simulations, tolerance studies, and the development of superconducting RF technology in the HoBiCaT test facility.  
 
MOPCH015 Impact of Undulator Wakefileds and Tapering on European X-ray FEL Performance undulator, FEL, simulation, SASE 83
 
  • I. Zagorodnov, M. Dohlus, T. Limberg
    DESY, Hamburg
  The European X-ray Free-Electron Laser (XFEL) based on self-amplified spontaneous emission (SASE) requires an electron beam with a few kA peak current and a small-gap undulator system up to 250 m in length. The interaction between the high-current electron bunch and the undulator vacuum chamber affects the FEL performance. In this paper we estimate the induced wakefields in elliptical pipe geometry, taking into account the main geometrical variations of the chamber. To study the expected performance in the presence of the calculated wakefields, we are doing start-to-end simulations with the tracking codes ASTRA, CSRtrack and GENESIS. To compensate the wakefield impact on the FEL performance, an adiabatic change of undulator parameters is considered.  
 
MOPCH016 Bunch Compression Monitor electron, FEL, SASE, acceleration 86
 
  • H. Delsim-Hashemi, J. Rossbach, P. Schmüser
    Uni HH, Hamburg
  • O. Grimm, H. Schlarb, B. Schmidt
    DESY, Hamburg
  • A.F.G. van der Meer
    FOM Rijnhuizen, Nieuwegein
  An accelerated bunch of electrons radiates coherently at wavelengths longer than or comparable to the bunch length. The first generation Bunch Compression Monitor (BCM) that is installed at the VUV-FEL applies this principle by measuring the total radiation intensity. For a better control on the degree of the compression, the radiated intensity in different bandwidth can be used. Dependent on the changes in the structure of the bunch, its radiation spectrum changes correspondingly. A new generation BCM uses wavelength dependent diffracting devices and multi-channel sensors to measure the signal in different wavelength channels simultaneously. This paper describes the construction of the first prototypes and experimental results in different short wavelength bands measured at the linac of the VUV-FEL at DESY, Hamburg.  
 
MOPCH024 Future Seeding Experiments at SPARC FEL, undulator, laser, resonance 95
 
  • L. Giannessi, S. Ambrogio, F. Ciocci, G. Dattoli, A. Doria, G.P. Gallerano, E. Giovenale, M. Quattromini, A. Renieri, C. Ronsivalle, I.P. Spassovsky
    ENEA C.R. Frascati, Frascati (Roma)
  • D. Alesini, M.E. Biagini, R. Boni, M. Castellano, A. Clozza, A. Drago, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, M. Migliorati, L. Palumbo, C. Sanelli, F. Sgamma, B. Spataro, S. Tomassini, C. Vaccarezza, C. Vicario
    INFN/LNF, Frascati (Roma)
  • M. Bougeard, B. Carré, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Salieres, O. Tcherbakoff
    CEA, Gif-sur-Yvette
  • M.-E. Couprie
    SOLEIL, Gif-sur-Yvette
  • A. Dipace, E. Sabia
    ENEA Portici, Portici (Napoli)
  • M. Mattioli, P. Musumeci, M. Petrarca
    Università di Roma I La Sapienza, Roma
  • M. Nisoli, G. Sansone, S. Stagira, S. de Silvestri
    Politecnico/Milano, Milano
  • L. P. Poletto, G. T. Tondello
    Univ. degli Studi di Padova, Padova
  • L. Serafini
    INFN-Milano, Milano
  Sources based on High order Harmonics Generated in gases (HHG) with high power Ti:Sa lasers pulses represent promising candidates as seed for FEL amplifiers for several reasons, as spatial and temporal coherence, wavelength tunability and spectral range, which extends down to the nm wavelength scale. This communication describes the research work plan that is under implementation at the SPARC FEL facility in the framework of the EUROFEL programme. The main goal of the collaboration is to study and test the amplification and the FEL harmonic generation process of an input seed signal obtained as higher order harmonics generated both in crystals (400 nm and 266 nm) and in gases (266 nm, 160 nm, 114 nm). The SPARC FEL can be configured to test several cascaded FEL layouts that will be analysed in this contribution.  
 
MOPCH030 Production of Coherent X-rays with a Free Electron Laser Based on an Optical Wiggler laser, electron, emittance, FEL 113
 
  • V. Petrillo, A. Colzato
    Universita' degli Studi di Milano, Milano
  • A. Bacci, C. Maroli, L. Serafini
    INFN-Milano, Milano
  • M. Ferrario
    INFN/LNF, Frascati (Roma)
  The interaction between high-brightness electron beams and counter-propagating laser pulses produces X rays via Thomson scattering. If the laser source is long enough, the electrons bunch on the scale of the emitted X-ray wavelength and a regime of collective effects establishes. In this case, the FEL instability develops and the system behaves like a FEL based on an optical undulator. Coherent X-rays are irradiated, with a bandwidth thinner than that of the incoherent emission. The emittance of the beam and gradients or irregularities in the laser energy distribution are the principal factors that limit the growth of the X-ray signal. We analyse with a 3-D code the transverse effects in the emission produced by a relativistic electron beam when it is under the action of an optical laser pulse and the X-ray spectra obtained. The scalings typical of the optical wiggler, with very short gain lengths and overall time durations of the process make possible considerable emission also in violation of the Pellegrini criterion for static wigglers. A generalized form of this criterion is validated on the basis of the numerical evidence.  
 
MOPCH031 Progress on the Pi-mode X-band RF Cavity for SPARC simulation, vacuum, emittance 116
 
  • L. Ficcadenti, M.E. Esposito, A. Mostacci, L. Palumbo
    Rome University La Sapienza, Roma
  • D. Alesini, B. Spataro
    INFN/LNF, Frascati (Roma)
  • A. Bacci
    INFN-Milano, Milano
  The Frascati photo-injector SPARC (Pulsed Self Amplified Coherent Radiation Source) will be equipped with an x-band RF cavity for linearizing emittance to enhance bunch compression and for reducing bunch longitudinal energy spread. The nine cell standing wave cavity prototype made of separated cells has been already built and measured*. In this paper we report on characterization of the first brazed prototype. Heat load studies have been performed as well to design the cooling system for the final device.

*D. Alesini et al. Nucl. Instr. and Meth. A 554 (2005) 1.

 
 
MOPCH034 On a Skeleton CASSINI Ovals Current Undulator undulator, electron, laser, free-electron-laser 119
 
  • A.M. Mihalache, V.I.R. Niculescu
    INFLPR, Bucharest - Magurele
  • V. Babin
    INOE, Bucharest
  • M.R. Leonovici, C. Stancu
    Bucharest University, Faculty of Physics, Bucharest-Magurele
  • F. Scarlat
    Valahia University, Faculty of Sciences, Targoviste
  A new undulator structure for free electron lasers was presented. Current skeleton CASSINI ovals produced magnetic fields which are spatially periodic. The current structure was in the shape of stacks of modified CASSINI ovals. The current has alternating directions. The magnetic field components for each wire present C2 symmetry. CASSINI undulator transverse cross-section* was approximated by polygons. In cartesian coordinates the Biot-Savart law was analytically evaluated. The magnetic field was mainly transversal and easily adjusted with the current. The versatility of this structure introduces a new type of two beams longitudinal undulator or wiggler design for transverse moments.

*Cassini curve; C. Mihu, I.P. Iambor-1989.

 
 
MOPCH043 An Optimization Study for an FEL Oscillator at TAC Test Facility FEL, electron, undulator, laser 136
 
  • Ö.M. Mete, Ö. Karsli, O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  Recently, conceptual design of the Turkic Accelerator Center (TAC) proposal was completed. The main goal of this proposal is a charm factory that consists of a linac-ring type electron-positron collider. In addition, synchrotron radiation from the positron ring and free electron laser from the electron linac are proposed. The project related with this proposal has been accepted by the Turkish government. It is planned that the Technical Design Report of TAC will have been written in the next three years. In this period, an infrared oscillator free electron laser (IR FEL) will be constructed as a test facility for TAC. 20 and 50 MeV electron energies will be used to obtain infrared FEL. The main parameters of the electron linacs, the optical cavities and the FEL were determined. The possible use of obtained laser beam in basic and applied research areas such as biotechnology, nanotechnology, semiconductors and photo chemistry were discussed.  
 
MOPCH044 Peculiarities of the Doppler Effect for Moving Radiative Particles in Dispersive Medium at Extreme Conditions photon 139
 
  • M.V. Vysotskyy, V.I. Vysotskii
    National Taras Shevchenko University of Kyiv, Radiophysical Faculty, Kiev
  The features of Doppler effect for fast moving radiating particles with discrete energy levels spectrum (e.g. radiation at channeling) at parameters close or equal to extreme condition of Cherenkov effect are studied. The formal usage of Cherenkov condition leads in this case to incorrect and unphysical results. The main task of this work was to find maximal radiation frequency and its dependence from the system parameters. This finite frequency was found. It was shown that at correct use of conservation laws the dependence of radiation and absorption frequencies on deviation from exact Cherenkov condition contains one discontinuity. The value of these frequencies on two sides of this discontinuity is different by 2.5 times. It was shown that the positions of these discontinuities depend on deviation value and corresponds to the condition of normal Doppler effect transformation into abnormal. Conditions that correspond to maximal radiation and absorption frequencies are different and are shifted in different directions form the exact Cherenkov condition (in relation to the velocity and dielectric permittivity).  
 
MOPCH051 Operation of the First Undulator-based Femtoslicing Source laser, electron, photon, background 154
 
  • S. Khan
    Uni HH, Hamburg
  • K. Holldack, T. Kachel, T. Quast
    BESSY GmbH, Berlin
  • R. Mitzner
    Universität Muenster, Physikalisches Institut, Muenster
  At the BESSY II storage ring, a source of sub-100-fs x-ray pulses with tunable polarization and excellent signal-to-background ratio has been constructed in 2004, based on laser-induced energy modulation ("femtoslicing"*) and subsequent angular separation of the short-pulse x-rays from an elliptical undulator. After commissioning and characterizing the source, short-pulse radiation is now routinely delivered for pump-probe applications. The paper summarizes the results from commissioning and operational experience as well as possible upgrade options.

*A. Zholents and M. Zoloterev, PRL 76 (1996), 912.

 
 
MOPCH053 Towards Sub-picoseconds Electron Bunches: Upgrading Ideas for BESSY II optics, electron, focusing, storage-ring 157
 
  • G. Wuestefeld, J. Feikes, P. Kuske
    BESSY GmbH, Berlin
  Sub-picoseconds bunches were achieved with the BESSY low alpha optics, and their lengths were measured using Fourier Transform spectroscopy*. To avoid the coherent synchrotron radiation instability, the current in these short bunches has to be limited to theμampere level. An upgrade of the BESSY II rf gradient to much larger values is suggested to overcome this low current limitation by two orders of magnitude. Intense, picoseconds long bunches could then be achieved already at the regular user optics. The resulting short and very intense electron bunches are useful for generation of short x-ray pulses and powerful THz-radiation. Expected parameters of bunch length and current are discussed.

*J. Feikes et al. "Sub-Picoseconds Electron Bunches in the BESSY Storage Ring", EPAC'04, Luzerne (Switzerland), July 2004.

 
 
MOPCH054 Plans for the Generation of Short Radiation Pulses at the Diamond Storage Ring DIAMOND, storage-ring, optics, synchrotron 160
 
  • R. Bartolini
    Diamond, Oxfordshire
  • M. Borland, K.C. Harkay
    ANL, Argonne, Illinois
  Diamond is a third generation light source under commissioning in Oxfordshire UK. In view of the increasing interest in the production of short radiation pulses, we have investigated the possibility to operate with a low-alpha optics, the use of a third harmonic cavity for bunch shortening and the implementation of a crab cavity scheme in the Diamond storage ring. The results of the initial accelerator studies will be described, including the modification of the beam optics, non-linear beam dynamics optimisation and choice of RF parameters for the crab cavity operation. The expected performance of these schemes will be summarised.  
 
MOPCH055 Circulation of a Short, Intense Electron Bunch in the NewSUBARU Storage Ring linac, injection, storage-ring, CSR 163
 
  • Y. Shoji, Y. Hisaoka, T. Matsubara, T. Mitsui
    NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
  • T. Asaka, S. Suzuki
    JASRI/SPring-8, Hyogo-ken
  One new method is proposed which supplies synchrotron radiation light from a short and intense electron bunch. This method supplies a short and intense x-ray pulse and extremely strong coherent radiation in a long wavelength region to beam lines of a storage ring. SPring-8 linac supplied a short and intense 1.0 GeV electron beam to NewSUBARU storage ring. The electron bunch was compressed to 10ps (full width) from the normal condition (20ps full width) using ECS system. The pulse charge was 0.10nC/bunch and the energy spread was (±) 0.2 % (full width) at the injection point. The ring lattice was adjusted at a quasi-isochronous condition to keep the short bunch for many revolutions. The estimated linear and non-linear momentum compaction factors were -6·10-5 (the linear factor), 0.0 (the second order factor) and +0.9 (the third order factor). The bunch length was measured by a streak camera, and the coherent radiation was detected by a Shottky diode detector. The short bunch was successfully circulated for about 50 turns.  
 
MOPCH062 Centroid, Size, and Emittance of a Slice in a Kicked Bunch synchrotron, emittance, betatron, photon 172
 
  • C.-X. Wang, W. Guo
    ANL, Argonne, Illinois
  A transversely kicked bunch will decohere due to, among other things, chromatic and amplitude-dependent tune shifts. The chromatic tune shift leads to correlation between transverse and longitudinal phase space. Such a correlation can be used for compressing synchrotron radiation of the bunch with adequate optics. In this report, we revise the decoherence calculation to derive the centroid and second moments of a beam slice in a kicked bunch, taking into account chromatic and nonlinear decoherence, but neglecting wakefield and radiation damping, etc. A simple formula for estimating slice bunch length (and potential pulse compression ratio) is given for the ideal situation.  
 
MOPCH066 The Conceptual Design of 4GLS at Daresbury Laboratory linac, electron, FEL, undulator 181
 
  • J.A. Clarke
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  4GLS is a novel next generation proposal for a UK national light source to be sited at Daresbury Laboratory, based on a superconducting energy recovery linac (ERL) with both high average current photon sources (undulators and bending magnets) and three high peak current free electron lasers. Key features are a high gain, seeded FEL amplifier to generate XUV radiation and the prospect of advanced research arising from unique combinations of sources with femtosecond pulse structure. The conceptual design is now completed and a CDR recently published. The 4GLS concept is summarised, highlighting how the significant design challenges have been addressed, and the project status and plans explained.  
 
MOPCH139 Results and Experience with Single Cavity Tests of Medium Beta Superconducting Quarter Wave Resonators at TRIUMF linac, heavy-ion, acceleration, ion 375
 
  • V. Zviagintsev, K. Fong, M.P. Laverty, R.E. Laxdal, A.K. Mitra, T.C. Ries, I. Sekachev
    TRIUMF, Vancouver
  A heavy ion superconducting linac is being installed at ISAC/TRIUMF. A first stage of the ISAC-II upgrade will see the installation of 20 quarter wave bulk niobium cavities (Beta0=0.057,0.071). The cavities operate CW at 106MHz with design peak fields of Ep=30MV/m, Bp=60mT while delivering an accelerating voltage of 1.08MV at <7W power consumption. All cavities have been tested in a single cavity test stand with twenty of twenty-one meeting ISAC-II specifications. The cavity test results will be presented. In particular we will discuss our experience with BCP vs. EP surface treatments and with Q-disease. In addition the tuning plates of two of the cavities were modified to provide a unique compensation to the resonant frequency.  
 
MOPCH144 Low Temperature Properties of Piezoelectric Actuators Used in SRF Cavities Cold Tuning Systems TESLA, target, cyclotron, LHC 390
 
  • G. Martinet, S. Blivet, F. Chatelet, M. Fouaidy, N. Hammoudi, A. Olivier, H. Saugnac
    IPN, Orsay
  High accelerating gradients (10 MV/m for SNS, 33 MV/m for ILC) at which SRF cavities will be operated in pulsed machines induce frequency shift much higher than the resonator bandwidth. This so-called Lorentz detuning should be compensated dynamically by means of an active piezo-tuning system. In the frame of the CARE project activities supported by EU, IPN Orsay participates to the development of a fast cold tuning system based and piezoelectric technology for SRF cavities operating at temperature T=2K. The aim of this study is the full characterization of piezoelectric actuators at low temperature including dielectric properties (capacitance, impedance, dielectric losses), radiation hardness tests (fast neutron tolerance), mechanical measurements (maximum displacement, maximum stroke) and thermal properties (heating, heat capacity). Results obtained in the temperature range from 2K up to 300K will be presented and discussed.  
 
MOPCH152 A Pulsed-RF High-power Processing Effect of Superconducting Niobium Cavities observed at the ELBE Linear Accelerator controls, ELBE, resonance, linac 413
 
  • U. Lehnert, H. Buettig, P. Michel, Ch. Schneider, R. Schurig
    FZR, Dresden
  • A. Buechner, F.G. Gabriel
    FZR/FWFE, Dresden
  The driver LINAC of the ELBE radiation source is built for cw operation. However, in some cases a pulsed-mode operation was desired to extend the otherwise stringent gradient limits. The main restriction results from field emission that decreases the Q of the cavities which was evaluated from measurements of the liquid helium consumption. After pulsed-mode operation with gradients exceeding the maximum cw accelerating gradients by 30–40\% a significant reduction in the field emission was observed. This in turn allows higher accelerating gradients to be used in cw as well. We attribute this behaviour to an rf-processing of the cavity surface which burns off field emitters.  
 
MOPCH167 PBG Superconducting Resonant Structures lattice, pick-up, cryogenics, simulation 454
 
  • M.R. Masullo
    INFN-Napoli, Napoli
  • A. Andreone, E. Di Gennaro, F. Francomacaro, G. Lamura
    Naples University Federico II, Napoli
  • V. Palmieri, D. Tonini
    INFN/LNL, Legnaro, Padova
  • M. Panniello, V.G. Vaccaro
    Naples University Federico II and INFN, Napoli
  We have realized normal conducting and superconducting “open resonators” based on the Photonic Band Gap (PBG) concept. We present the study, the optimisation and the measurements (from room temperature to 1.5 K) of Copper and Niobium PBG accelerating cavities operating at two different frequencies, 6 GHz and 16 GHz. All the structures are realised by extruding a single bulk piece of material, using a new machining method that minimizes the surface losses caused by the contact between different conducting parts. Measurements on the compact (54 mm external diameter) 16 GHz Nb structure are very good, showing in the superconducting state a quality factor Q =1.2x105 at the lowest temperature (1.5 K), limited by radiation losses only. The shunt impedance measured for the 16 GHz prototype is 70 MOhm/m, underlining the applicability of such resonant structures as accelerating cavities.  
 
MOPCH186 First Cool Down of the Juelich Accelerator Module Based on Superconducting Half-Wave Resonators vacuum, shielding, instrumentation, COSY 496
 
  • F.M. Esser, B. Laatsch, H.S. Singer, R. Stassen
    FZJ, Jülich
  • R. Eichhorn
    TU Darmstadt, Darmstadt
  In the context of upgrading the existing proton and deuteron accelerator facility COSY at the Forschungszentrum Juelich, an accelerator module based on superconducting half wave resonators is prototyped. Due to beam dynamics, the requirements of cavity operation and a top-loading design for mounting, the cryostat had to be designed very compact and with a separate vacuum system for beam and insulation vacuum. These restricted requirements lead to very short cold-warm transitions in beam port region and to an unconventional design regarding to the shape of the cryostat vessel. This paper will review the design constraints, gives an overview of the ancillary parts of the module (cavities, tuner, etc.) and will present the results of the first cool-down experiments. Furthermore the future work will be presented.  
 
MOPLS012 The LHC Sector Test LHC, controls, injection, instrumentation 559
 
  • M. Lamont, R. Bailey, H. Burkhardt, B. Goddard, L.K. Jensen, O.R. Jones, V. Kain, A. Koschik, R.I. Saban, J.A. Uythoven, J. Wenninger
    CERN, Geneva
  The proposal to inject beam into a sector of the partially completed LHC is presented. The test will provide an important milestone, force preparation of a number of key systems, and allow a number of critical measurements with beam. The motivation for the test is discussed, along with the proposed beam studies, the radiation issues and the potential impact on ongoing installation. The demands on the various accelerator systems implicated are presented along with the scheduling of the preparatory steps, the test itself and the recovery phase.  
 
MOPLS013 The Roman Pot for LHC vacuum, LHC, optics, scattering 562
 
  • M. Oriunno, M. Deile, K. Eggert, J.-M. Lacroix, S.J. Mathot, E.P. Noschis, R. Perret, E.R. Radermacher, G. Ruggiero
    CERN, Geneva
  The LHC machine will be equipped with Roman Pot stations by the TOTEM experiment to measure the pp total cross section and to study the elastic scattering and the diffraction physics processes. TOTEM needs to bring the pots, equipped with cold micro-strip silicon detectors, as a close as possible to the high intensity beam of LHC. Because of the special optics required by TOTEM, the beam has a transversal size of only 80 microns at the Roman pot locations. Safety considerations for the machine protection set the limit to 10 ?, i.e. 800 μm. Such unprecedented parameters, together with the issues of the Ultra High Vacuum and the RF compatibility, and the harsh radiation environment, have requested a design for the Roman Pot system, which is compliant with the LHC requirements and operations. To better meet also the challenging requirements of TOTEM, a technology development of a thin window has been pursued and a flatness of less than 50 μm has been obtained by brazing foil of 150 μm thicknesses. A prototype of the Roman Pot and of the thin window box have been manufactured and tested. We describe the main issues of the final design and the results of the preliminary tests.  
 
MOPLS020 Rad-hard Luminosity Monitoring for the LHC LHC, luminosity, CERN, controls 580
 
  • A. Ratti, J.-F. Beche, J.M. Byrd, K. Chow, S. De Santis, P. Denes, B. Ghiorso, H.S. Matis, M. T. Monroy, W.C. Turner
    LBNL, Berkeley, California
  • E. Bravin
    CERN, Geneva
  • P.F. Manfredi
    Pavia University, Engineering faculty, Pavia
  • W. Vandelli
    Pavia University, Pavia
  Luminosity measurements at the high luminosity points of the LHC are very challenging due to the extremely high radiation levels in excess of 1 GGy/yr. We have designed an ionization chamber that uses a flowing gas mixture and a combination of metals and ceramics. With such a choice, an additonal challenge is achieving the necessary speed to be able to resolve bunch-by-bunch luminosity data. We present the design, analysis and experimental results of the early demonstration tests of this device.  
 
MOPLS033 Beam-beam Limit and Feedback Noise feedback, damping, luminosity, kicker 619
 
  • K. Ohmi, Y. Funakoshi, S. Hiramatsu, K. Oide, M. Tobiyama
    KEK, Ibaraki
  Beam-beam interaction is strongly nonlinear, therefore particles in the beam experience chaotic motion. A small noise can be enhanced by the chaotic nature, with the result that unexpected emittance growth can be observed. We study the noise of transverse bunch by bunch feedback system and related luminosity degradation. Similar effects caused by crab cavity noise is also discussed.  
 
MOPLS049 Anomalous High Radiation Beam Aborts in the PEP-II B-factory vacuum, background, SLAC, luminosity 652
 
  • M.K. Sullivan, Y. Cai, S. DeBarger, F.-J. Decker, S. Ecklund, A.S. Fisher, S.M. Gierman, S.A. Heifets, R.H. Iverson, A. Kulikov, N. Kurita, S.J. Metcalfe, A. Novokhatski, J. Seeman, K.G. Sonnad, D. Teytelman, J.L. Turner, U. Wienands, D. Wright, Y.T. Yan, G. Yocky
    SLAC, Menlo Park, California
  The PEP-II B-factory at SLAC has recently experienced unexpected beam losses due to anomalously high radiation levels at the BaBar detector. The problem was finally traced to the occurrence of very high pressure (>100 nTorr) spikes that have a very short duration (few seconds). We describe the events and show analysis predicting where in the vacuum system the events originated and describe what was discovered in the vacuum system.  
 
MOPLS073 Shower Simulations, Comparison of Fluka, Geant4 and EGS4 simulation, target, SLAC, electron 718
 
  • L. Fernandez-Hernando
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R.J. Barlow
    UMAN, Manchester
  • A. Bungau
    Cockcroft Institute, Warrington, Cheshire
  • L. Keller
    SLAC, Menlo Park, California
  • N.K. Watson
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  Computer simulations with different packages (Fluka, Geant4 and EGS4) were run in order to determine the energy deposition of an ILC bunch in a spoiler of specified geometry at various depths. The uncertainty in these predictions is estimated by comparison of their results. Various candidate spoiler designs (geometry, material) are studied. These shower simulations can be used as inputs to thermal and mechanical studies using programs such as ANSYS.  
 
MOPLS082 Simulation of the ILC Collimation System Using BDSIM, MARS15 and STRUCT collimation, extraction, simulation, SLAC 744
 
  • J. Carter, I.V. Agapov, G.A. Blair, L. Deacon
    Royal Holloway, University of London, Surrey
  • A.I. Drozhdin, N.V. Mokhov
    Fermilab, Batavia, Illinois
  • Y. Nosochkov, A. Seryi
    SLAC, Menlo Park, California
  The simulation codes STRUCT, MARS15 and BDSIM are used to simulate in detail the collimation section of the ILC. A comparative study of the collimation system performance is performed, and the key radiation loads are calculated. Results for the latest ILC designs are presented together with their implications for future design iterations.  
 
MOPLS105 Collimators for ILC undulator, positron, target, electron 807
 
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  We considered two types of collimators for usage in undulator conversion system of ILC. In the first, the Pyrolytic graphite is used and it is installed in front of a target; the second one uses InGa alloy in rotating cylinder. The last one installed in front of undulator. Collimators allow absorption single train on bunches in ILC and enhace the photon polarization.  
 
MOPLS138 Space Charge and Equilibrium Emittances in Damping Rings emittance, space-charge, damping, lattice 882
 
  • M. Venturini
    LBNL, Berkeley, California
  • K. Oide
    KEK, Ibaraki
  • A. Wolski
    Liverpool University, Science Faculty, Liverpool
  The unusual combination of small beam size and long ring circumference may cause space charge to have noticeable effects on the beam dynamics of the ILC (International Linear Collider) damping rings. One possible consequence is a modification of the vertical equilibrium emittance resulting from a non-ideal lattice. One simple way to account for this effect is to model space charge in the linear approximation within the framework of Oide's envelope (or Chao's matrix) formalism, whis is commonly used to calculate equilibrium emittances in lepton storage rings. However, this model would likely overestimate the effect as a linear approximation for space charge is accurate only in a small neighborhood of a bunch center. For a more accurate modelling, we propose to make use of Sacherer's envelope equations consisting of a closed set of equations for the second moments of a beam distribution that account for the nonlinear dependence of the space-charge force. Here we will illustrate how Sacherer's equations can be combined with Oide's formalism and apply the result to the ILC damping rings.  
 
TUYPA01 Femtosecond Bunch Length Measurements diagnostics, laser, electron, CDR 915
 
  • S.P. Jamison
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • G. Berden
    FOM Rijnhuizen, Nieuwegein
  • W.A. Gillespie, P.J. Phillips
    University of Dundee, Nethergate, Dundee, Scotland
  • A. MacLeod
    UAD, Dundee
  • B. Steffen
    DESY, Hamburg
  The measurement of ultrashort longitudinal bunch profiles is of growing importance to accelerator development and operation. With requirements of ~10fs time resolution, and a desire for non-destructive and real time diagnostics, the challenges for diagnostic development are significant. Alongside more established transverse deflecting cavity and CTR measurement techniques, new approaches arriving from the field of ultrafast lasers offer significant potential; Ultrafast electro-optic detection has now been demonstrated on several accelerators, and in many distinct forms, although challenges remain in getting to the desired time resolution. Proposed schemes combining ultrafast laser diagnostics with FEL interactions, such as the "optical replica" scheme also have considerable potential. Here, an overview of the current status of femtosecond scale longitudinal profile diagnostics will be given, together with an outlook to the future expectations.  
slides icon Transparencies
 
TUOAFI02 Design of a Treatment Control System for a Proton Therapy Facility controls, proton, cyclotron, target 958
 
  • J.E. Katuin, J.C. Collins, C. Hagen, W. Manwaring, P. Zolnierczuk
    IUCF, Bloomington, Indiana
  The IUCF Proton Therapy System (PTS)is designed by Indiana University and operated by the Midwest Proton Radiotherapy Institute (MPRI) to deliver proton radiation treatment to patients with solid tumors or other diseases susceptible to radiation. PTS contains three Treatment Systems, each consisting of four subsystems: Beam Delivery, Dose Delivery, Patient Positioning and Treatments Control. These systems are implemented using different operating systems, control software, and hardware platforms. Therefore, IUCF developed an XML network communication protocol so that subsystems could issue commands to and receive feedback and status from other subsystems over a local area network (LAN). This protocol was also applied to the MPRI clinical database used to access patient treatment plans. The treatment control system was designed so that a single user interface could be used to deliver proton therapy. The use of the XML and the LAN allowed the software of the treatment control system to be designed such that the various systems are treated as objects with properties and methods. This approach not only simplified the overall design of the treatment control system, it also simplified the effort required for software validation, testing, and documentation.  
slides icon Transparencies
 
TUOCFI01 Radiation Measurements vs. Predictions for SNS Linac Commissioning linac, shielding, CCL, SNS 977
 
  • I.I. Popova, F. X. Gallmeier, P. L. Gonzalez, D. C. Gregory
    ORNL, Oak Ridge, Tennessee
  Detailed predictions for radiation fields, induced inside and outside of the accelerator tunnel, were performed for each of the SNS accelerator commissioning stages, from the ion source through the entire LINAC. Analyses were performed for normal commissioning parameters, for worst possible beam accidents, and for beam fault studies, using the Monte Carlo code MCNPX. Proper temporary shielding was developed and installed in local areas near beam termination points (beam stops) and some critical locations, such as penetrations, in order to minimize dose rates in general occupied areas. Areas that are not full-time occupied and have dose rates above a specified limit during beam accident and fault studies were properly restricted. Radiation monitoring was performed using real time radiation measurement devices and TLDs to measure absorbed dose and dose equivalent rates. The measured radiation fields were analyzed and compared with transport simulations. TLD readings vs. calculations are in a good agreement, generally within a factor of two difference. A large inconsistency among instrument readings is observed, and an effort is underway to understand the variations.  
slides icon Transparencies
 
TUPCH016 Numerical Simulation of Synchrotron Radiation for Bunch Diagnostics simulation, vacuum, DESY, synchrotron 1031
 
  • A. Paech, W. Ackermann, T. Weiland
    TEMF, Darmstadt
  • O. Grimm
    DESY, Hamburg
  For the operation of the VUV-FEL at DESY, Hamburg, the longitudinal charge distribution of the electron bunches that drive the free electron laser is of high importance. One novel method to measure the bunch shape is to analyze the coherent far-infrared synchrotron radiation generated at the last dipole magnet of the first bunch compressor. For the correct interpretation of the results it is mandatory to know how various parameters, like the bunch shape and path, the vacuum chamber walls, the optical beamline, etc., influence the observed spectrum. The aim of this work is to calculate the generation of synchrotron radiation inside the bunch compressor with the emphasis of including the effects of the vertical and horizontal vacuum chamber walls in the vicinity of the last dipole magnet. Challenging problems for the numerical simulations are the very short wavelength and the broad frequency range of interest. As a first step, it is shown how the radiation leaving the vacuum chamber, that is generated by a single point charge, can be calculated with the help of the uniform theory of diffraction (UTD).  
 
TUPCH021 Principles of longitudinal beam diagnostics with coherent radiation electron, DESY, diagnostics, laser 1040
 
  • O. Grimm
    DESY, Hamburg
  The Kramers-Kronig dispersion relation connects the real and imaginary part of a response function under very general assumptions. It is used in the context of accelerator physics for longitudinal bunch diagnostics as a phase retrieval technique: the modulus of the complex form factor (the Fourier transform of the charge distribution) is accessible experimentally, and the missing phase then (partially) reconstructed to allow an inversion of the Fourier transform. Contrary to real and imaginary part, the connection between modulus and phase is not unique anymore due to the possibility of zeros of the form factor in the complex frequency plane that cannot be measured. This paper gives a mathematically explicit, step-by-step derivation of the phase reconstruction technique for bunch diagnostics, and it explains the problem of zeros and their practical effect with some examples. The intention is not utmost mathematical rigour, but a clear, accessible explanation of all steps involved.  
 
TUPCH027 Time Resolved Single-shot Measurements of Transition Radiation at the THz Beamline of FLASH using Electro-optic Spectral Decoding electron, laser, FEL, DESY 1058
 
  • B. Steffen, E.-A. Knabbe, B. Schmidt
    DESY, Hamburg
  • G. Berden, A.F.G. van der Meer
    FOM Rijnhuizen, Nieuwegein
  • W.A. Gillespie, P.J. Phillips
    University of Dundee, Nethergate, Dundee, Scotland
  • S.P. Jamison, A. MacLeod
    UAD, Dundee
  • P. Schmüser
    Uni HH, Hamburg
  Single-shot electro-optic detection was used to measure the temporal profile of coherent transition radiation (CTR) pulses at the VUV-FEL at DESY. The CTR was generated from single bunches kicked to an off-axis screen, with the radiation transported through a 20m long transfer line imaging the CTR from a radiation screen to an experimental station outside the accelerator tunnel. Bipolar pulses with a FWHM less than 1ps have been measured and are consistent with simulations of the propagation of radiation through the transfer line.  
 
TUPCH032 Precise Measurements of the Vertical Beam Size in the ANKA Storage Ring with an In-air X-ray Detector resonance, synchrotron, electron, photon 1073
 
  • A.-S. Müller, I. Birkel, E. Huttel, P. Wesolowski
    FZK, Karlsruhe
  • K.B. Scheidt
    ESRF, Grenoble
  A major part of the X-rays generated in the ANKA dipole magnets is unused by the experimental beamlines and is, on a number of dipoles, absorbed in a conical shaped Copper absorber. The 8 mm thickness that it presents lets a tiny fraction of the hard X-rays above 70KeV enter the free air space behind it. The transmitted power of only a few uW/mrad hor. is sufficient to be detected, with sub-second measurement time, by a novel In-Air X-ray detector. This extremely compact and low-cost device is situated just behind the absorber. The design, developed and in use at the ESRF, is based on a Cadmium Tungstenate (CdWO4) scintillator converting X-rays into visible light that is collected and focused onto a commercial CCD camera. Since the small vertical divergence of the high energy photons and the distance of the detector from the source point are known, it is possible to derive the vertical electron beam size with a high intrinsic precision. This paper presents results of beam size measurements as a function of various ANKA machine parameters, that illustrates the great diagnostic potential of this type of detector for a 2.5GeV medium energy light source like ANKA.  
 
TUPCH038 Beam Loss Monitoring and Machine Protection Designs for the Daresbury Laboratory Energy Recovery Linac Prototype electron, beam-losses, ERLP, monitoring 1088
 
  • S.R. Buckley, R.J. Smith
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Daresbury Laboratory is currently constructing an energy recovery linac prototype (ERLP). This is to carry out the necessary research and development of the technology of photo-cathode electron guns and superconducting linacs so that a fourth generation light source (4GLS) can be designed and constructed. Beam loss monitoring and machine protection systems are vital areas for the successful operation of the ERLP. These systems are required, both for efficient commissioning and for hardware protection during operation. This paper gives an overview of the system requirements, options available and details of the final design specification.  
 
TUPCH042 The Optical System for a Smith-Purcell Experiment at 45MeV background, vacuum, cryogenics, electron 1097
 
  • V. Blackmore, W.W.M. Allison, G. Doucas, C. Perry
    OXFORDphysics, Oxford, Oxon
  • P.G. Huggard
    CCLRC/RAL, Chilton, Didcot, Oxon
  • M.B. Johnston
    University of Oxford, Clarendon Laboratory, Oxford
  • B. Redlich, A.F.G. van der Meer
    FOM Rijnhuizen, Nieuwegein
  Smith-Purcell (SP) radiation has been used to investigate the longitudinal profile of a 45MeV, picosecond long bunched beam at the FELIX facility, FOM Institute. The three important optical elements that made this experiment possible were (i) high quality optical filters, (ii) nonimaging light concentrators, (iii) and a system to rapidly change between gratings.  
 
TUPCH043 Observations of the Longitudinal Electron Bunch Profile at 45MeV Using coherent Smith-Purcell radiation electron, background, linear-collider, collider 1100
 
  • G. Doucas, V. Blackmore, B. Ottewell, C. Perry
    OXFORDphysics, Oxford, Oxon
  • P.G. Huggard
    CCLRC/RAL, Chilton, Didcot, Oxon
  • M.B. Johnston
    University of Oxford, Clarendon Laboratory, Oxford
  • M.F. Kimmitt
    University of Essex, Physics Centre, Colchester
  • B. Redlich, A.F.G. van der Meer
    FOM Rijnhuizen, Nieuwegein
  Coherent Smith-Purcell (SP) radiation has been used to determine the longitudinal profile of the electron bunch at the FELIX facility, FOM Institute. Far-infrared radiation was detected using a simple, compact arrangement of 11 pyroelectric detectors. Background radiation was suppressed through the use of high quality optical filters, and an efficient light collection system. The measured bunch profile was most closely in agreement with 90% of the particles contained within 5.5ps, with an approximately triangular temporal profile.  
 
TUPCH053 Bunch Length Characterization Downstream from the Second Bunch Compressor at FLASH DESY, Hamburg electron, FEL, CDR, SASE 1127
 
  • E. Chiadroni
    INFN-Roma II, Roma
  The characterization of the longitudinal density profile of picosecond and sub-picosecond relativistic particle bunches is a fundamental requirement in many particle accelerator facilities, since knowledge of the characteristics of the accelerated beams is of utmost importance for the successful development of the next generation light sources and linear colliders. The development of non-intercepting beam diagnostics is thus necessary to produce and control such beams. First experimental evidences of the non-intercepting nature of diffraction radiation diagnostics are given. The longitudinal bunch distribution downstream of the second bunch compressor of the DESY TTF VUV-FEL has been reconstructed using a frequency-domain technique based on the autocorrelation of coherent diffraction radiation. Due to the low and high frequency suppression, introduced by the experimental apparatus, only a portion of the CDR spectrum participates to the reconstruction of the longitudinal bunch profile. The knowledge of the system frequency response is then crucial in order to correct the results and extrapolate a bunch shape as close as possible to the real one.  
 
TUPCH062 Synchrotron Radiation Diagnostics for the NSLS Booster booster, synchrotron, diagnostics, synchrotron-radiation 1154
 
  • T.V. Shaftan, I. Pinayev
    BNL, Upton, Long Island, New York
  We developed an optical diagnostics system for the NSLS booster-synchrotron utilizing the synchrotron radiation from the dipole magnet. MATLAB based software allows to study the electron beam properties along the energy ramp. The trajectory, beam sizes and coupling at the different instants of time are retrieved from the analysis of the electron beam image. In the paper we present the system layout, as well as experimental results and upgrade plans.  
 
TUPCH067 Time-resolved Beam Emittance Measurement of Dragon-I Linear Induction Accelerator emittance, focusing, induction, electron 1166
 
  • G.J. Yang, S. Chen, X. Jiang, Z. Zhang
    CAEP/IFP, Mainyang, Sichuan
  A beam emittance diagnostic system of an intense pulsed electron beam (20MeV, 2.6kA, 80ns) based on optical transition radiation is developed. A gated CCD camera is used to get time-resolved result. We develop a timing system to avoid the time jitter, an anti-interference system to avoid the electromagnetic interference, and a C++ code to deal with the experimental data. The measured emittance is about 2000¦Ð.mm.mrad, which is agree with the result of three gradient method.  
 
TUPCH072 New Generation Streak Camera Design and Investigation electron, space-charge, monitoring, simulation 1175
 
  • A.M. Tron
    LPI, Moscow
  • T.V. Gorlov, I.G. Merinov
    MEPhI, Moscow
  The only method for electron bunch duration monitoring with a resolution in the order of 10 fs and less is the method of photochronography of the bunch incoherent radiation in the frequency range, for example, of visible light and at realizing streak camera with new principles of its operation*. In the paper the streak camera design for measuring both the electron bunches and x-ray pulses duration with the mentioned temporal resolution is presented. The results of the camera investigation, with photoelectron dynamics simulation taking into account space-charge effect and impact of the surface roughness of a spherical photocathode of the 20-50 micrometers radius (forming a modulating gap of spherical configuration) on the camera resolution, are presented and discussed.

*A. M. Tron and I. G. Merinov. Method of bunch radiation photochronography with 10 femtosecond and less resolution. http://www.physics.ucla.edu/PAHBEB2005/talks/10oct2005/wg2/atron.pdf

 
 
TUPCH079 Characterisation of the MAX-II Electron Beam: Beam Size Measurements optics, synchrotron, electron, synchrotron-radiation 1193
 
  • M. Sjöström, H. Tarawneh, E.J. Wallén
    MAX-lab, Lund
  Over the last year investigations of the MAX-II electron beam characteristics have been made. Examples of investigated parameters include the beam size, bunch length, vacuum and Touschek lifetimes, and the machine functions. Several upgrades of the MAX II ring have been performed since the commissioning 1995 like a new 100 MHz RF system with a 500 MHz Landau cavity, exchanged injector, and a variety of insertion devices. There is hence a need to systematically characterize the present machine. This systematic characterisation is now underway and this article describes details of the beam size measurements.  
 
TUPCH083 Time-resolved Spectrometry on the CLIC Test Facility 3 electron, photon, linac, synchrotron 1205
 
  • T. Lefevre, C.B. Bal, H.-H. Braun, E. Bravin, S. Burger, R. Corsini, S. Doebert, C.D. Dutriat, F. Tecker, P. Urschütz, C.P. Welsch
    CERN, Geneva
  The high charge (>6microC) electron beam produced in the CLIC Test Facility 3 (CTF3) is accelerated in fully loaded cavities. To be able to measure the resulting strong transient effects, the time evolution of the beam energy and its energy spread must be measured with at least 50MHz bandwidth. Three spectrometer lines were installed all along the linac in order to control and tune the beam. The electrons are deflected by a dipole magnet onto an Optical Transition Radiation (OTR) screen, which is observed by a CCD camera. The measured beam size is then directly related to the energy spread. In order to provide time-resolved energy spectra, a fraction of the OTR photons is sent onto a multichannel photomultiplier. The overall set-up is described, special focus is given to the design of the OTR screen with its synchrotron radiation shielding. The performance of the time-resolved measurements are discussed in detail. Finally, the limitations of the system, mainly due to radiation problems, are discussed.  
 
TUPCH089 Investigations of OTR Screen Surfaces and Shapes CTF3, focusing, diagnostics, electron 1220
 
  • C.P. Welsch, E. Bravin, T. Lefevre
    CERN, Geneva
  Optical transition radiation (OTR) has proven to be a flexible and effective tool for measuring a wide range of beam parameters, in particular the beam divergence and the transverse beam profile. It is today an established and widely used diagnostic method providing linear real-time measurements. Measurements in the CLIC Test Facility (CTF3) showed that the performance of the present profile monitors is limited by the optical acceptance of the imaging system. In this paper, two methods to improve the systems' performance are presented and results from measurements are shown. First, the influence of the surface quality of the OTR screen itself is addressed. Several possible screen materials have been tested to which different surface treatment techniques were applied. Results from the measured optical characteristics are given. Second, a parabolic-shaped screen support was investigated with the aim of providing an initial focusing of the emitted radiation and thus to reduce the problem of aperture limitation. Measured and calculated emission distributions are presented.  
 
TUPCH090 Electron Beam Profile Measurements with Visible and X-ray Synchrotron Radiation at the Swiss Light Source synchrotron, emittance, SLS, synchrotron-radiation 1223
 
  • Å. Andersson, M. Rohrer, V. Schlott, A. Streun
    PSI, Villigen
  • O.V. Chubar
    SOLEIL, Gif-sur-Yvette
  Two different methods of beam profile measurements using a) visible-to-UV range synchrotron radiation b) X-ray synchrotron radiation have been realized in a single diagnostics beam line at the Swiss Light Source. While the visible-to-UV part uses a focusing lens to create an image of the electron beam cross section, the X-ray part makes use of the pinhole camera principle. In the visible-to-UV case the vertically polarized synchrotron radiation renders an image heavily influenced by inherent emission and diffraction effects of synchrotron radiation. This turns out to be an advantageous influence in order to determine ultra small beam profiles. For each of the two methods practical point-spread function measurements, including all beam line components, and high-precision wave-optics based calculations (SRW code) of the synchrotron light characteristics were performed to ensure correct interpretation of the measured profiles. Results from both monitors will be presented to allow comparison.  
 
TUPCH095 Status of Synchrotron Radiation Monitor at TLS synchrotron, synchrotron-radiation, controls, booster 1232
 
  • C.H. Kuo, J. Chen, K.-T. Hsu, S.Y. Hsu, K.H. Hu, D. Lee, C.-J. Wang
    NSRRC, Hsinchu
  Synchrotron radiation monitor of the Taiwan Light Source have been upgraded recently. Improvement of optics and modelling was performed to improve accuracy of measurement for small beam size. Synchrotron light interferometer is implemented for complementary measurement. IEEE-1394 digital CCD camera is used to improve image transmission quality, camera remote control and to extend dynamic range. Intensify gated camera are included in this upgrade for dynamic property observation of the stored beam. Functionality enhancement of image analysis is also supported. Efforts and achievements will be summarized in this report.  
 
TUPCH096 High-intensity Bremsstrahlung Monitoring System for Photonuclear Technologies electron, photon, simulation, target 1235
 
  • V.L. Uvarov, S.P. Karasyov, V.I. Nikiforov, R.I. Pomatsalyuk, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev, Yu.V. Zhebrovsky
    NSC/KIPT, Kharkov
  The realization of promising photonuclear technologies (a soft technology for medical isotope production, radioactive waste handling, activation analysis, etc) calls for the sources of high-energy (Egamma>10MeV) and high-intensity (>=10E03W/cm2) photons. These sources may by obtained by converting a beam from a high-current electron Linac into bremsstrahlung. The method of combined activation of a set of foils that have different energy thresholds of the (gamma,n) reactions is proposed to determine the space-energy characteristics of such radiation. In each energy range the geometrical characteristics of the bremsstrahlung flux are reconstructed from the foil surface gamma-activity distribution. The last one is determined through one-dimensional scanning of the foils by a specially designed detecting head that includes a linear matrix of 16 collimated semiconductor detectors (CdZnTe; 2x2x2,mm). A preliminary analysis of the system geometry and applicability of the method was performed by computer simulation based on the PENELOPE software. A developed PC based measuring system with CAMAC interface is described.  
 
TUPCH097 Instrumentation and Operation of a Remote Operation Beam Diagnostics Lab at the Cornell Electron-positron Storage Ring optics, positron, electron, synchrotron 1238
 
  • R. Holtzapple, J.S. Kern, P.J.S. Stonaha
    Alfred University, Alfred, New York
  • B. Cerio
    Colgate University, Hamilton, New York
  • M.A. Palmer
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Accelerator beam diagnostics are being modified at the Laboratory of Elementary Particle Physics (LEPP) at Cornell University for remote operation at nearby Alfred University. Presently, a streak camera used for longitudinal dynamics measurements on the Cornell Electron-Positron Storage Ring (CESR) is operational and measurements have been made from Alfred University [1]. In the near future, photomultiplier tube arrays for electron and positron vertical beam dynamics measurements will be remotely operated as well. In this paper, we describe instrumentation and operation of the remote beam diagnostics.  
 
TUPCH100 Fiberoptics-based Instrumentation for Storage Ring Longitudinal Diagnostics synchrotron, coupling, synchrotron-radiation, diagnostics 1247
 
  • S. De Santis, J.M. Byrd, A. Ratti, M.S. Zolotorev
    LBNL, Berkeley, California
  • Y. Yin
    Y.Y. Labs, Inc., Fremont, California
  Many beam diagnostic devices in today's synchrotron rings make use of the radiation emitted by the circulating particles. Such instruments are placed in close proximity of the accelerator, where in many instances they cannot be easily accessed for safety consideration, or at the end of a beamline, which because of its cost, can only move the light port a few meters away from the ring. We present a study on the coupling of synchrotron light into an optical fiber for all those application where the longitudinal properties of the beam are measured (i.e., bunch length, phase, intensity, etc.). By choosing an appropriate fiber it is possible to keep attenuation and dispersion at negligible values over a large bandwidth, so that this method would allow to have the diagnostic instruments directly in the control room, or wherever convenient, up to several hundred of meters away from the tunnel. This would make maintaining and replacing instruments, or switching between them, possible without any access to restricted areas. Additionally, the few components required to be near the ring (lenses and couplers) in order to couple the light into the fiber are intrinsically radiation-hard.  
 
TUPCH114 A Ridged Circular Waveguide Ferrite Load for Cavity HOM Damping vacuum, damping, simulation, impedance 1280
 
  • E. Weihreter, V. Duerr, F. Marhauser
    BESSY GmbH, Berlin
  A normal conducting HOM damped 500 MHz prototype cavity has been tested with three tapered circular double ridged waveguide to coaxial transitions as HOM couplers, featuring maximum longitudinal and transverse HOM impedances below 5 kOhm and 200 kOhm/m respectively. Numerical simulations indicate that these impedance levels can be further reduced by more than a factor of 3 using homogeneous circular double ridged waveguides for improved coupling to the HOMs. In the present paper the layout of an optimised homogeneous waveguide with "in vacuum" ferrite tiles is presented, including mechanical and thermal design considerations. Low power reflectrometry measurements demonstrate good matching of a prototype load, and high power tests of the ferrite absorber elements indicate that the waveguide load is well suited for the cavity HOM power levels present in state of art 3rd generation SR sources.  
 
TUPCH155 2D and 1D Surface Photonic Band Gap Structures for Accelerator Applications electron, plasma, SLAC, undulator 1388
 
  • I.V. Konoplev, A.W. Cross, W. He, P. MacInnes, A. Phelps, C.W. Robertson, K. Ronald, C.G. Whyte
    USTRAT/SUPA, Glasgow
  High frequency (26.5GHz to 40GHz), high power (tens of MW) microwave sources are required for cavity testing and conditioning applications in accelerators such as CLIC. The first study of microwave radiation from a co-axial Free-Electron Maser (FEM) based on a two-mirror cavity formed by a 2D Surface Photonic Band Gap (SPBG) structure (input mirror 10.4cm) and 1D SPBG structure (output mirror 10cm) is presented. The electron beam source consisted of a magnetically insulated plasma flare emission carbon cathode. Application of a 450kV voltage pulse of duration ~250ns across the cathode and grounded anode resulted in the production of a 7.0cm diameter annular electron beam of current ~1500A. The output radiation power from the FEM was measured using a Ka-band horn with 60dB of attenuation in front of a microwave detector located at a distance of 1.5m from the output window. By integrating the microwave power measured at the detector over the radiation pattern a total power of 50 (±10) MW corresponding to an efficiency of ~9% was calculated. The location of the operating frequency was found to lie between 35GHz and 39GHz, which agrees with theoretically predicted frequency of 37.2GHz.  
 
TUPCH171 Calculation, Measurement and Analysis of Vacuum Pressure Data and Related Bremsstrahlung Levels on Straight Sections of the ESRF vacuum, ESRF, storage-ring, optics 1417
 
  • R. Kersevan, P. Berkvens, P. Colomp
    ESRF, Grenoble
  One of the major personal safety issues of modern synchrotron radiation (SR) light sources is the minimization of the exposure of beamline staff and users to high-energy bremsstrahlung (BS) radiation generated in the straight sections of the storage ring and entering the optics hutches of the beamlines. This is particularly important when insertion device (ID) narrow-gap chambers are installed, nowadays characterized by very low specific conductances. At the ESRF, this has led to the implementation of systematic measurements of BS levels and vacuum conditioning curves, in conjunction with the installation of non-evaporable getter (NEG)-coated ID chambers. A dedicated beamline is used to do on-axis measurements of the BS intensity during the initial conditioning period of newly installed NEG-coated ID chambers. This paper will show results of measurements and calculations performed throughout the years, and comment on the suitability from the radiation safety point of view of the installation of NEG-coated chambers in large numbers around the ring.  
 
TUPCH172 Status Report on the Performance of NEG-coated Chambers at the ESRF vacuum, ESRF, CERN, beam-losses 1420
 
  • R. Kersevan, M. Hahn, i. Parat
    ESRF, Grenoble
  At the ESRF, the use of NEG-coated narrow gap chambers for insertion device (ID) straight sections has become the standard choice for in-air IDs. A total of 25 chambers have been installed at different times in the ring, with 19 being installed as of Jan 2006, for a total length of 82 m. The vacuum performance has been excellent for all but one of them. It has been found that the now standard "10mm" design, i.e. a 5 m-long, 57x8 mm2 ellipse, is compatible with the multi-bunch operation at 200 mA. Runs at higher currents, performed in preparation of current upgrades, have gone smoothly. During 2005, a 3.5 m-long prototype of a chamber suited for installation in the achromat part of the lattice has been installed in the ring. It was characterized by a much smaller cross-section (30x20 mm2, HxV) as compared to a standard chamber (74x33 mm2, HxV), and by the absence of three lumped pumps, replaced by the NEG-coating. The data taken during a full run have been extremely encouraging, to the point of considering the adoption of a similar design for a future upgrade of the storage ring lattice and vacuum system. A status report will be given, alongside with a discussion of future plans.  
 
TUPCH182 Radiation Monitors as a Vacuum Diagnostic in the Room Temperature Parts of the LHC Straight Sections LHC, vacuum, background, hadron 1441
 
  • V. Talanov
    IHEP Protvino, Protvino, Moscow Region
  • V. Baglin, T. Wijnands
    CERN, Geneva
  In the absence of collisions, inelastic interactions between protons and residual gas molecules are the main source of radiation in the room temperature parts of the LHC long straight sections. In this case the variations in the radiation levels will reflect the dynamics of the residual pressure distribution. Based on the background simulations for the long straight section of the LHC IP5 and on the current understanding of the residual pressure dynamics, we evaluate the possibility to use the radiation monitors for the purpose of the vacuum diagnostic, and we present the first estimates of the predicted monitor counts for different scenarios of the machine operation.  
 
TUPLS002 Dust Macroparticles in HERA and DORIS electron, vacuum, storage-ring, simulation 1486
 
  • A. Kling
    DESY, Hamburg
  Charged dust macroparticles are considered as sources of sudden beam lifetime breakdowns detected in many electron storage rings. This phenomenon is still observed in HERA, although the distributed ion pumps, which were previously identified as dust particle sources, have been removed. We report on the observations of trapped dust during the last period of electron operation and present a detailed model of dust macroparticle dynamics in the HERA e-ring and in DORIS with particular emphasis on stability and possible trapping processes.  
 
TUPLS141 Measured Residual Radioactivity Induced by U Ions of Energy 500 MeV/u in a Cu Target target, ion, GSI, radioactivity 1834
 
  • E. Mustafin, H. Iwase, E. Kozlova, D. Schardt
    GSI, Darmstadt
  • A. Fertman, A. Golubev
    ITEP, Moscow
  • R. Hinca, M. Pavlovic, I. Strasik
    STU, Bratislava
  • N. Sobolevskiy
    RAS/INR, Moscow
  Several laboratories in the world have started or plan to build new powerful ion accelerators. These facilities promise to provide very valuable tools for experiments in fundamental nuclear physics, physics of high energy density in matter and for medical applications as well. One of the most important problems that have to be solved during the design stage is the radiation protection of the accelerator. Due to the complexity, it is hardly possible to obtain reliable radionuclide production data for accelerator structure materials from radiation transport codes. Thus, the experimental data which can be measured at the presently existing facilities are necessary for the evaluation of the induced levels of radioactivity around intense heavy ion accelerators. The Uranium beam losses are the most dangerous ones in the FAIR facility. Results of the measurement of activation induced by U beam with energy of E = 500 MeV/u in the copper target are presented in this paper.  
 
WEOAPA03 MICE Overview - Physics Goals and Prospects emittance, focusing, scattering, photon 1870
 
  • M. Yoshida
    Osaka University, Osaka
  Ionization cooling, a technique in which muon beam is passed through a series of absorbers and followed by RF-acceleration, is a proposed method for cooling muon beam, i.e., phase-space reduction. The international Muon Ionisation Cooling Experiment (MICE), which will construct and operate a realistic cooling channel and measure the beam cooling performance, is the first essential step towardsrealization of nutrino factories and eventually muon colliders based on intense muon sources. The MICE have got approved to be constructedin Rutherford Appleton Laboratory (RAL) and the fist beam commissioning is scheduled in 2007. The physics goal and future prospects of the MICE together with the beamline and the instruments which is now being built will be described.  
slides icon Transparencies
 
WEYFI01 Modelling of Space Charge and CSR Effects in Bunch Compressor Systems CSR, simulation, space-charge, emittance 1897
 
  • M. Dohlus
    DESY, Hamburg
  Bunches with high peak currents of the order of kilo-Amperes are required in linac based X-ray free electron lasers. These bunches cannot be produced directly in guns because space charge forces would destroy the brilliance within a short distance. Therefore bunches with a peak current of a few tens of Amperes are created in laser-driven radio-frequency sources and are compressed in length by two orders of magnitude. In most designs, the compression is achieved in magnet chicanes, where particles with different energies have different path lengths so that a bunch with an energy distribution correlated with longitudinal particle position can shrink in length. The principle problem is that short bunches on curved trajectories will emit coherent synchrotron radiation (CSR). The CSR effects and the space charge fields play an important role in the particle dynamic and the design of a bunch compression system. This presentation will provide an overview of computational methods and simulation tools for space charge and coherent synchrotron radiation effects in magnetic bunch compression systems.  
slides icon Transparencies
 
WEOFI01 Beam Dynamics Measurements in the Vicinity of a Half-integer Resonance betatron, emittance, resonance, beam-beam-effects 1902
 
  • T. Ieiri, J.W. Flanagan, H. Fukuma, H. Ikeda, Y. Ohnishi, K. Oide, M. Tobiyama
    KEK, Ibaraki
  The operating point of the betatron tune set near a half-integer is a crucial parameter to make high luminosity in electron/positron ring colliders. Dynamic beam-beam effects would change the optics parameters of the colliders, depending on the betatron tune and the beam-beam parameter. On the other hand, existence of the half-integer stopband makes the beam unstable. Therefore, beam behavior near a half-integer might provide interesting issues from the viewpoint of beam dynamics. We measured a frequency response of the beam across a half-integer for measuring the betatron tune at KEKB. A sharp spike just at a half-integer was observed in the tune spectrum. We believe that the spectrum would be a nonlinear resonance caused by some off-momentum particles in a bunch, not by a coherent motion of a whole bunch. The horizontal beam size measured using a synchrotron radiation monitor indicated a slight increase when the tune approached a half-integer. The variations in the beam size are discussed, considering both dynamic beam-beam effects and a beta beat due to the half-integer stopband.  
slides icon Transparencies
 
WEPCH004 Estimation of Transverse Coupling From Pinhole Images coupling, emittance, resonance, wiggler 1921
 
  • X.R. Resende, P.F. Tavares
    LNLS, Campinas
  The Brazilian Synchrotron Light Laboratory (LNLS) has recently started filling its storage ring straight sections with insertion devices. Last year a 2-Tesla Wiggler was successfully installed and integrated in the control system. An elliptically polarizing undulator is now under construction and scheduled to be installed in the next shutdown, by the end of the current year. The VUV beamline for the undulator is very demanding with respect to orbit stability and other beam parameters. Considerable reduction of the vertical emittance via reduction of the transverse coupling is a must in order for the undulator beamline to achieve its promised outstanding performance. In this paper we report on recent efforts to better understand the residual coupling in the machine and we describe preliminary proposals of viable solutions that aim at controlling the linear coupling within beamline specifications.  
 
WEPCH005 Advances in Beam Orbit Stability at the LNLS Electron Storage Ring storage-ring, synchrotron, vacuum, shielding 1924
 
  • L. Liu, R.H.A. Farias, M.J. Ferreira, S.R. Marques, F. Rodrigues, P.F. Tavares, R.P.C.C. Tenca
    LNLS, Campinas
  We describe recent efforts made at the Brazilian Synchrotron Light Source (LNLS) to improve beam orbit stability. The main driving force is the high positional stability required by some specific experiments and particularly by a high resolution undulator beamline which is being built at LNLS. Recent steps taken to improve orbit stability include the development of x-ray BPMs to measure the vertical position of the x-ray beam, analysis of RF BPM movement due to thermal load induced by synchrotron radiation after injection, new algorithms to deal with BPM electronics or control board false readings and revision and modification of their installations. In addition a weighted least squares method was developed to account for global correction while simultaneously privileging some local source point position. These upgrades are part of an ongoing work to improve beam orbit stability at LNLS.  
 
WEPCH021 Generalized Twiss Coefficients Including Transverse Coupling and E-beam Growth undulator, electron, emittance, CSR 1966
 
  • F. Ciocci, G. Dattoli
    ENEA C.R. Frascati, Frascati (Roma)
  • M. Migliorati
    Rome University La Sapienza, Roma
  We use a generalization of the Twiss coefficients to the fully transverse coupled case. We show that the formalism is particularly useful to treat problems involving the beam optics of electrons propagating in undulators or solenoids. The method allows the treatment in analytical terms, we generalize the method including the effect of spatial charges and higher order multi-polar terms. The method is then applied to a specific example relevant to e-beam emittance dilution in solenoid and exotic undulators.  
 
WEPCH040 Further Development of Irradiation Field Forming Systems of Industrial Electron Accelerators electron, target, vacuum, extraction 2005
 
  • N.G. Tolstun, A.S. Ivanov, V.P. Ovchinnikov, M.P. Svinin
    NIIEFA, St. Petersburg
  Electron beam irradiation field forming systems where accelerated electron beam is scanned in a constant field of the elongated bending magnets were developed in our institute more than 15 years ago and they have a number of advantages in comparison with traditional ones. Since than they have been applied in two accelerators with energies 300 and 400 keV; version of the similar system with two electromagnets for two-side irradiation of flexible materials – in a number of 750 keV high voltage accelerators ("Electron-10") successfully operating now in several industrial lines. Systems of forming of electron beam irradiation field based on the same principle have been used in several projects, some of them are already put into operation. Electron optic characteristics of such systems and their various modifications as well as aspects of their possible usage are discussed in the paper.  
 
WEPCH073 Asymptotic Analysis of Ultra-relativistic Charge electromagnetic-fields, vacuum, electron, controls 2086
 
  • D.A. Burton, J. Gratus, R. Tucker
    Lancaster University, Lancaster
  A new approach is developed for analysing the dynamic behaviour of distributions of charged particles in an electromagnetic field. Noting the limitations inherent in the Lorentz-Dirac equation for a single point particle, a simple model is proposed for a charged continuum interacting self-consistently with the Maxwell field in vacuo. The model is developed using intrinsic tensor field theory and exploits to the full the symmetry and light-cone structure of Minkowski spacetime. This permits the construction of a regular stress-energy tensor whose vanishing divergence determines a system of non-linear partial differential equations for the velocity and self-fields of accelerated charge. Within this covariant framework a particular perturbation scheme is motivated by an exact class of solutions to this system describing the evolution of a charged fluid under the combined effects of both self and external electromagnetic fields. The scheme yields an asymptotic approximation in terms of inhomogeneous linear equations for the self-consistent Maxwell field, charge current and time-like velocity field of the charged fluid and is defined as an ultra-relativistic configuration.  
 
WEPCH110 Calculation of Wake Potentials in General 3D Structures impedance, extraction, vacuum, controls 2170
 
  • H. Henke
    TET, Berlin
  • W. Bruns
    CERN, Geneva
  The wake potential is defined as an integration along an axis of a structure. It includes the infinitely long beam pipe regions and in case of numerical evaluation leads to pipe wake artefacts. If the structure is cavity like one can position the integration path on the pipe wall and only the integration over the cavity gap remains. In case of axis-symmetric protruding structures it was proposed by O. Napoly et al. to deform the path such that the integration in the pipe regions is again on the wall. The present paper generalizes this method of path deformation to 3D structures with incoming and outgoing beam pipes. Its usefulness is verified with the code GdfidL and no artifacts were observed.  
 
WEPCH111 Time Domain Radiation of a Gaussian Charge Sheet Passing a Slit in a Conducting Screen scattering, ITY 2173
 
  • M. Filtz, H. Henke
    TET, Berlin
  A semi-analytical method is proposed to calculate in time-domain the radiation of a relativistic Gaussian charge sheet travelling parallel to a slotted conducting screen. The method is based on transient line current elements as basis functions which have a triangular time dependence. Making use of duality magnetic current elements are used in the slot region. Radiation fields are shown and the transverse kick received by a test charge is given. The dual problem, the scattering of the fields at a conducting strip, is also treated. The main purpose of the paper is to present an effective algorithm which is easy to implement for computing and visualising plane scattering and diffraction problems in time domain.  
 
WEPCH127 Analysis of Radiative Effects in the Electron Emission from the Photocathode and in the Acceleration inside the RF Cavity of a Photoinjector using the 3D Numerical Code RETAR electron, acceleration, extraction, brightness 2221
 
  • V. Petrillo, C. Maroli
    Universita' degli Studi di Milano, Milano
  • G. Alberti
    Università degli Studi di Milano, Milano
  • A. Bacci, A.R. Rossi, L. Serafini
    INFN-Milano, Milano
  • M. Ferrario
    INFN/LNF, Frascati (Roma)
  The three-dimensional fully relativistic and self-consistent code RETAR has been developed to model the dynamics of high-brightness electron beams and in particular to assess the importance of the retarded radiative part of the emitted electromagnetic fields in all conditions where the electrons experience strong accelerations. In this analysis we evaluate the radiative energy losses in the electron emission process from the photocathode of an injector, during the successive acceleration of the electron beam in the RF cavity and the focalization due to the magnetic field of the solenoid, taking also into account the e.m. field of the laser illuminating the cathode. The analysis is specifically carried out with parameters of importance in the framework of the SPARC and PLASMONX projects.  
 
WEPCH131 Development of Numerical Code for Self-consistent Wake Field Analysis with Curved Trajectory Electron Bunches simulation, electron, electromagnetic-fields, coupling 2230
 
  • H. Kawaguchi
    Muroran Institute of Technology, Department of Electrical and Electronic Engineering, Muroran
  • K. Fujita
    Hokkaido University, Sapporo
  Strongly interacting phenomena of electromagnetic radiation fields and ultra-relativistic electron is one of great interests in accelerator science such as in electron beam dynamics at the bunch compressor. The phenomena are described by time domain boundary value problem for the Lienard-Wiechert solutions. Authors develop a time domain boundary element method for self-consistent wake fields analysis of electromagnetic fields and charged particles. To use boundary integral equation for describing the electromagnetic fields, the time domain boundary value problems for the Lienard-Wiechert solution can be naturally formulated and we can simulate the wake fields phenomena with electron beam dynamics. In this paper, beam dynamics of curved trajectory electron bunches inside uniform beam tube are numerically simulated by using 2.5 dimension time domain boundary element technique. Various effects of closed beam tube for ultra-relativistic electron dynamics are considered comparing with the Lienard-Wiechert solutions in free space.  
 
WEPCH143 Electron Linac Based e,X-radiation Facility target, electron, photon, simulation 2257
 
  • V.I. Nikiforov, A. Dovbnya, N.A. Dovbnya, V.L. Uvarov
    NSC/KIPT, Kharkov
  In a number of technologies based on high-current electron accelerators bremsstrahlung is generated in the interaction of the beam with the irradiated object. Thus, in addition to the electron radiation, the bremsstahlung may be used for carring out of different technolodgical programs (e,X-facility). A method for the numerical analysis and optimization of the radiation characteristics of such installation is proposed. The accelerator beam track, starting from the electron source and up to output devices is considered as a single multicomponent target consisting of the layers of different materials. The thickness of each layer is measured in the generalized units of the "stopping length". Using the method of simulation based on the PENELOPE/2001 system the characteristics of the mixed e,gamma-radiation field (energy yield of electrons, photons and their ratio) as function of the stopping length for actual or anticipated version of output equipment can be calculated. To illustrate the method, the parameters of the beam path of the NSC KIPT Linacs used as e,X-facilities was analyzed.  
 
WEPCH144 CSR Effects in a Bunch Compressor: Influence of the Transverse Force and Shielding shielding, LEFT, CSR, simulation 2260
 
  • G. Bassi, J.A. Ellison, K.A. Heinemann
    UNM, Albuquerque, New Mexico
  We study the influence of CSR on particle bunches traveling on arbitrary planar orbits between parallel conducting plates with a fixed "vertical" charge distribution. Our goal is a numerical solution of the 2 degree-of-freedom Vlasov-Maxwell equations. This provides simulations with lower numerical noise than the macroparticle method and allows the study of emittance degradation and microbunching. As reported*, we calculate the fields excited by the bunch in the lab frame using a new formula that leads to a simplification. The Vlasov equation is integrated in the beam frame interaction picture using the method of local characteristics. The transformation between traditional beam frame and lab frame coordinates is carefully treated. Here we report on our implementation of the algorithm in the context of a chicane bunch compressor**, where the strong correlation between phase space variables requires an adaptive grid. In particular, we present a complete analysis (moments + reduced densities) of the bunch evolution under the fields produced by the unperturbed bunch density. Finally, our progress on the fully self-consistent case is discussed.

* Vlasov treatment of coherent synchrotron radiation from arbitrary planar orbits, Nucl. Instr. Meth. Phys. Res. A, in press.** ICFA Beam Dynamics Mini-Workshop on CSR, Berlin-Zeuthen, 2002. See http://www.desy.de/csr.

 
 
WEPCH158 Status of the Hadrontherapy ETOILE-Project in Lyon proton, ion, GSI, hadron 2299
 
  • M.J. Bajard
    UCBL, Villeurbanne
  The ETOILE project is the French program for carbon ion beams in cancer treatment. It is now in the final phase. However its development is not only aiming at the building of a medical facility, around the project a broad set of medical and scientific programs have been initiated. The project has been supported by the University of Lyon and extended to the Rhône-Alpes Region and then gained a national visibility with governmental recognition. Many studies have been financed by ETOILE: in beam PET with new solutions, organ motion modelization, tumor cell radioresistance, medico-economical simulation and epidemiological previsions. The facility will be able to produce carbon ion beams and protons. Three treatment rooms are planned, two with horizontal beams and one with an isocentric gantry. The facility will be build in Lyon, through a process using as much as possible well established technology with the other facilities in Europe. The cost will be around 105 M€ afforded by loans and subventions. The subventions are funded from the Rhône-Alpes Region, the city of Lyon and the ministries of Health and Research. The running cost of the centre, for one thousand patients per year, is estimated to be 21 M€.  
 
WEPCH172 Electron Beam Pulse Processing toward the Intensity Modified Radiation Therapy (IMRT) electron, laser, cathode, gun 2334
 
  • T. Kondoh, S. Tagawa, J. Yang, Y. Yoshida
    ISIR, Osaka
  Radiation therapy attracts attention as one of the cancer therapies nowadays. Toward the next generation of the intensity modified radiation therapy (IMRT), the processing of electron beam pulse is studied using a photo cathode RF gun linac. Accelerated electron pulses will be converted to x-ray pulses by a metal target bremsstrahlung method or by a laser inverse Compton scattering method. Recently, the radiation therapy of cancer is developing to un-uniform irradiation as IMRT. A photo cathode RF gun is able to generate a low emittance electron beam pulse using a laser light pulse. We thought that a photo cathode RF gun can generate intensity and shape modified electron beam by processing of incident laser light. Because of a low emittance, an electron pulse is able to accelerate keeping shape. Electron beam processing by photo masks in incident optical system and generated beams are reported here. Images on photo masks were transported to a cathode surface by optical relay imaging. Beams were monitored by Desmarquest (Cr:Al2O3) luminescence. Spatially separation of a spot to a spot is about 0.3mm. Modified electron beam has fine spatial resolution.  
 
WEPCH173 The Performance of Double-grid O-18 Water Target for FDG Production target, cyclotron, proton, simulation 2337
 
  • H.B. Hong, J.-S. Chai, M.G. Hur, H.S. Jang, J. Kang
    KIRAMS, Seoul
  • H.H. Cho, K.M. Kim
    Yonsei University, Seoul
  The main stream of our study about the target is increasing the lifetime of the target windows. Mainly we conduct our study to increase the cooling performance and secondly about the structural design of the targets and target window foils. We already had developed and had published the results of our research about O-18 double-grid water target, which had installed on our 13 MeV cyclotron KIRAMS-13. The beam size of the accelerated proton was 9 mm*18 mm (0.35 in * 0.7 in). The double-grid target shows relatively low pressure during irradiation and good yield of F-18. The average yield of F-18 after irradiation was more than 1 Ci at 12.5 MeV , around 26 μA. Additionally, we are conducting new research for new techniques to increase the performance of low energy double-grid target and a new state-of-the-art pleated double foil target.  
 
WEPCH175 Design of 12 MEV RTM for Multiple Applications linac, electron, acceleration, microtron 2340
 
  • A.V. Poseryaev, V.I. Shvedunov
    MSU, Moscow
  • M.F. Ballester, Yu.A. Kubyshin
    UPC, Barcelona
  Design of a compact 12 MeV race-track microtron (RTM) is described. The results of operating wavelength choice, accelerating structure and end magnets optimization and beam dynamics simulation are represented. Use of a C-band linac and rare earth permanent magnet end magnets permit to design RTM, which is more compact and more effective as compared with the same energy circular microtron or linac. Electron beam with energy 4-12 MeV in 2 MeV step can be extracted from RTM. The estimated pulsed RF power required for feeding the linac is about 800 kW, total mass of accelerator is less than 40 kg and its dimensions are about 500x200x110 mm3.  
 
WEPCH177 Conception of Medical Isotope Production at Electron Accelerator target, electron, simulation, isotope-production 2343
 
  • V.L. Uvarov, N.P. Dikiy, A. Dovbnya, V.I. Nikiforov
    NSC/KIPT, Kharkov
  A photonuclear method with the use of high-energy bremsstrahlung (Eg>8 MeV) of high intensity (>= 1004 W/cm2) provides a possibility of the ecologically safe production of a number of isotopes for nuclear medicine. The conditions of generation of the radiation field having such characteristics as well as the features of photonuclear production of W-181,Pd-103, Cu-67 and other radionuclides are considered in the report. At the initial stage the study of the isotope production is performed by means of the computer simulation in a simplified 2D geometry of the Linac output devices. The code on the base of the PENELOPE/2001 program system supplemented with the data on the excitation functions of the corresponding reactions was developed. The dependences of the isotope yield (gross and specific activity) on the electron energy (30…45 MeV), as well as, the data on absorbed energy of radiation in the targets of natural composition are represented. The experimental results confirm the data of modelling. Main trends of realization of the photonuclear method for isotope production and the necessary conditions of the increase of its yield are analysed.  
 
WEPCH179 The Indiana University Proton Therapy System proton, cyclotron, rfq, controls 2349
 
  • D. Friesel, V. Anferov, J.C. Collins, J.E. Katuin, S. Klein, D. Nichiporov, M. Wedeikind
    IUCF, Bloomington, Indiana
  The Midwest Proton Radiotherapy Institute (MPRI)was designed by the Indiana University Cyclotron Facility (IUCF)to deliver proton radiation treatment to patients with solid tumors or other diseases susceptible to radiation. The IUCF Proton Therapy System (PTS)has five unigue subsystems to perform the radiation treatment; Beam Delivery, Dose Delivery, Patient Positioning and Treatment Control systems. The MPRI Clinic began operations in 2003 with a single Fixed Horizontal Beam Line (FHBL)treatment room and is being expanded to include two additional treatment rooms utilizing modified IBA* 360 degree rotating gantry systems. The Gantry nozzles use a beam wobbling and energy stacking system to produce the lateral and longitudinal beam distributions required for patient treatment. A treatment control system** provides a single user interface to deliver and monitor Proton Therapy treatment. This paper will present an brief overview of the Proton Therapy Facility, the properties and examples of the beam performance of the unique Nozzle design, and a summary of the facility beam operations.

* Ion Beam Applications, Inc, Belgium ** Design of a Treatment Control System for a Proton Therapy Facility, Joe Katuin, these proceedings

 
 
WEPCH187 A Compact 5 MeV, S-band, Electron Linac Based X-ray Tomography System linac, electron, simulation, collimation 2370
 
  • L. Auditore, L. Auditore, R.C. Barnà, D. De Pasquale, D. Loria, A. Trifirò, M. Trimarchi
    INFN & Messina University, S. Agata, Messina
  • U. Emanuele, A. Italiano
    INFN - Gruppo Messina, S. Agata, Messina
  The availability of commercial X-ray tubes made of radiography and tomography two of the most used non-destructive testing techniques both in industrial and cultural heritage fields. Nevertheless, the inspection of heavy materials or thick objects requires X-ray energies larger than the maximum energy provided by commercial X-ray tubes (600 kV). For this reason, and owing to the long experience of the INFN-Gruppo Collegato di Messina in designing and assembling low energy electron linacs, at the Dipartimento di Fisica, Universita di Messina, a 5 MeV electron linac based X-ray tomographic system has been developed. The X-ray source, properly designed by means of the MCNP-4C2 code, provides a 16 cm diameter X-ray spot at the sample position and a beam opening angle of about 3.6 degree. The image acquisition system consists of a CCD camera (Alta Apogee E1, 768x512 pixel) and a GOS scintillating screen. Preliminary radiographies and tomographies showing the high quality performances of the tomographic system have been acquired. Finally, the compactness of the linac, is one of the advantages of this system that could be used for in situ inspections when huge structures have to be tested  
 
WEPCH194 Complex for X-ray Inspection of Large Containers electron, shielding, target, controls 2388
 
  • V.M. Pirozhenko, V.M. Belugin, V.V. Elyan, A.V. Mischenko, N.E. Rozanov, B.S. Sychev, V.V. Vetrov
    MRTI RAS, Moscow
  • Yu.Ya. Kokorovets, V.D. Ryzhikov, N.A. Shumeiko, S.Ya. Yatsenko
    Communar, Kharkov
  • A.N. Korolev, K.G. Simonov
    ISTOK, Moscow Region
  The X-ray inspection complex is intended for non-intrusive inspection of large containers in the seaport. The complex has been developed, manufactured, and tested. To provide two projections of irradiated container and ensure reliable inspection, the complex includes two sets each containing self-shielded X-ray source and L-shaped detector array. The X-ray source includes electron linear accelerator with 7.3 MeV energy, conversion target, local radiation shielding, and alignment means. The accelerator uses standing wave bi-periodic structure fed by magnetron generator with 2.8 GHz frequency. It provides intensive electron beam without application of external magnetic field for the beam focusing. This feature makes it possible to use massive local radiation shielding made from iron. The radiation shielding provides large attenuation of scattered X-rays and ensures the radiation safety for personnel as well as high sensitivity of detecting system and good penetrability of the complex.  
 
WEPLS022 ILC Beam Energy Measurement based on Synchrotron Radiation from a Magnetic Spectrometer photon, electron, synchrotron, synchrotron-radiation 2442
 
  • E. Syresin, B.Zh. Zalikhanov
    JINR, Dubna, Moscow Region
  • K.H. Hiller, H.J. Schriber
    DESY Zeuthen, Zeuthen
  • R.S. Makarov
    MSU, Moscow
  The magnetic spectrometer with a relative energy resolution of 5·10-5 was proposed for ILC beam energy measurements. The beam energy measurement is based on precise definition of the beam position at a resolution of 100 nm and B-field integral at an accuracy of 2E-5. A complementary method of the beam energy measurement is proposed at registration of synchrotron radiation (SR) from the energy spectrometer dipole magnets. The measurements of both edge horizontal positions for SR fan on a distance of 50-70 m downstream of the spectrometer magnets permit to determine the beam energy with required resolution. The main principles of the beam energy measurements based on SR, the numerical simulations of SR performed by the GEANT code and proposal of SR monitors with submicron resolution are discussed.  
 
WEPLS029 Monoenergetic 200fs (FWHM) Electron Bunch Measurement from the Laser Plasma Cathode electron, laser, plasma, cathode 2451
 
  • A. Maekawa, T. Hosokai, K. Kinoshita, K. Kobayashi, T. Ohkubo, T. Tsujii, M. Uesaka
    UTNL, Ibaraki
  • Y. Kondo, Y. Shibata
    Tohoku University, Sendai
  • T. Takahashi, A. Yamazaki
    KURRI, Osaka
  • A.G. Zhidkov
    NIRS, Chiba-shi
  A laser plasma accelerator is the most promising approach to compact accelerators that can generate femtosecond electron bunches. It is expected that the electron bunch duration less than 100fs can be achieved owing to the high frequency of plasma waves. Since the time-resolution of the fastest streak camera is only 200fs, we have to use the coherent transition radiation (CTR) measurement or E/O (electro-optical) method. We plan to perform a single-shot measurement by getting the whole CTR spectrum by a IR polychromator in near future. As the first step forward it, we used a IR bolometer with different filters and obtained the average spectrum. We can generate monoenergetic electron bunches in the condition of laser intensity 3x1019W/cm2 and electron density 6x1019cm-3. The charge is estimated to be about 10pC using ICT (Integrated Current Transformer). The electron bunch accelerated by plasma waves penetrates 300um Ti-foil, and transition radiation is emitted. We measure CTR spectrum using a bolometer. Spectrum distribution of CTR depends on the electron bunch distribution, therefore we can evaluate the bunch duration from it. In the experiment, bunch duration can be estimated.  
 
WEPLS032 Spin Tracking at the ILC damping, polarization, positron, synchrotron 2454
 
  • G.A. Moortgat-Pick, I.R. Bailey, D.P. Barber, J.A. Clarke, J.B. Dainton, O.B. Malyshev, G.A. Moortgat-Pick, D.J. Scott
    Cockcroft Institute, Warrington, Cheshire
  • E. Baynham, T.W. Bradshaw, A.J. Brummitt, F.S. Carr, Y. Ivanyushenkov, J. Rochford
    CCLRC/RAL, Chilton, Didcot, Oxon
  • P. Cooke, L.I. Malysheva
    Liverpool University, Science Faculty, Liverpool
  Polarized beams will play a key role in the physics programme at the International Linear Collider (ILC). It is expected that the electron and positron sources will be able to produce beams with polarizations of about 90% and 60% respectively. However, to obtain accurate measurements it is essential to have precise knowledge and control of the polarization at the interaction point itself. It follows that the theoretical calculations used for spin tracking must be guaranteed to match the anticipated 0.1% relative measurement uncertainty of the polarimeters. To meet this need, the heLiCal collaboration is developing a computer simulation to track the evolution of the polarization of bunches of electrons and positrons from the sources to the interaction point. We have studied the beam spin dynamics throughout the ILC including spin precession and radiative spin-flip processes in the positron source, damping rings, beam delivery system and the interaction region. We present the result of these studies with special emphasis on the impact of new theoretical calculations for the CAIN bunch-bunch simulation including full spin correlations and higher-order contributions.  
 
WEPLS063 Laser Driven Linear Collider laser, acceleration, collider, electron 2523
 
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  We represent the details of scheme allowing long term acceleration with >10GeV/m. The basis of the scheme is a fast sweeping device for laser bunch. After sweeping the laser bunch has a slope with respect to the direction of propagation. So the every cell of accelerating structure becomes illuminated locally only for the moment, when the particle is there. Self consistent parameters allow considering this type of collider as a candidate for post-ILC era.  
 
WEPLS083 Consolidation of the 45-year-old CERN PS Main Magnet System CERN, radioactivity, vacuum, LHC 2571
 
  • Th. Zickler, D. Bodart, W. Kalbreier, K.H. Mess, A. Newborough
    CERN, Geneva
  After a major coil insulation breakdown on two of the 45-year-old CERN PS main magnets in 2003, an extensive magnet consolidation program has been launched. This article reviews the analysis of the magnet state before the repair and the applied major improvements. An overview is given of the production of the new components, the actual refurbishment and the commissioning of the main magnet system after 18 months shut down.  
 
WEPLS114 Progress on the MICE Tracker Solenoid vacuum, emittance, power-supply, superconductivity 2646
 
  • M.A. Green, S.P. Virostek
    LBNL, Berkeley, California
  • W. Lau, S.Q. Yang
    OXFORDphysics, Oxford, Oxon
  This report describes the 400 mm warm bore tracker solenoid for the Muon Ionization Cooling Experiment (MICE). The 2.923 m long tracker solenoid module includes the radiation shutter between the end absorber focus coil modules and the tracker as well as the 2.780 meter long magnet cryostat vacuum vessel. The 2.554 m long tracker solenoid consists of two sections, a three-coil spectrometer magnet and a two-coil matching section that matches the uniform field 4 T spectrometer solenoid into the MICE cooling channel. The two tracker magnets are used to provide a uniform magnetic field for the fiber detectors that are used to measure the muon beam emittance at the two ends of the cooling channel. This paper describes the design for the tracker magnet coils and the 4.2 K cryogenic coolers that are used to cool the superconducting magnet. Interfaces between the magnet and the detectors are discussed.  
 
WEPLS135 Piezoelectric Transformer Based Continuous-conduction-mode Voltage Source Charge-pump Power Factor Correction Electronic Ballast APR, synchrotron, synchrotron-radiation 2694
 
  • R.L. Lin, H.-M. Shih
    NCKU, Tainan city
  • C.-Y. Liu, K.-B. Liu
    NSRRC, Hsinchu
  This paper presents the piezoelectric transformer (PT) based continuous-conduction-mode (CCM) voltage source (VS) charge-pump (CP) power factor correction (PFC) electronic ballast. By replacing L-C resonant tank and transformer in the conventional CCM VS CP PFC electronic ballast with PT, the cost and volume can be reduced. The main drawback of conventional electronic ballast is that the input current has a narrow conduction angle, which causes rich harmonic that pollute the power system. However, the conventional CCM VS CP PFC electronic ballast is able to solve this problem but still require larger volume. Since the equivalent circuit of PT is identical to the conventional L-C resonant tank used in CCM VS CP PFC electronic ballast, the L-C resonant tank can be replaced by the PT to reduce the cost and volume. In addition, the inherent input capacitance of the PT works as a turn-off snubber for the power switches to decrease the turn-off voltage spikes and thus reduces the turn-off losses of the switches. The results show that the electronic ballast using PT achieved high power factor and the switches can be operated under ZVS condition.  
 
THOPA01 Formation of Electron Bunches for Harmonic Cascade X-ray Free Electron Lasers electron, linac, CSR, laser 2738
 
  • M. Cornacchia, S. Di Mitri, G. Penco
    ELETTRA, Basovizza, Trieste
  • A. Zholents
    LBNL, Berkeley, California
  A relatively long electron bunch is required for an operation of harmonic cascade free electron lasers (FELs). This is because they repeatedly employ a principle when the radiation produced in one cascade by one group of electrons proceeds ahead and interacts with other electrons from the same electron bunch in the next cascade. An optical laser is used to seed the radiation in the first cascade. Understandably the length of the electron bunch in this situation must accommodate the length of the x-ray pulse multiplied by a number of cascades plus a time jitter between the arrival time of the electron bunch and a seed laser pulse. Thus a variation of the peak current along the electron bunch as well as slice energy spread and emittance may affect the performance of the FEL. In this paper we analyze all possible sources affecting the distributions and interplay between them and show how desirable distributions can be produced. Results are illustrated with simulations using particle tracking codes.  
slides icon Transparencies
 
THOPA02 Status of the SCSS Test Accelerator and XFEL Project in Japan emittance, electron, undulator, cathode 2741
 
  • T. Shintake
    RIKEN Spring-8 Harima, Hyogo
  Construction of the SCSS* 250 MeV test accelerator was completed in October 2005, and the beam commissioning was started in November 2005. The first light at visible wavelength, which is the spontaneous radiation from undulator, was observed right after machine commissioning. We expect the first SASE beam around 60 nm in 2006. The purpose of the test accelerator is to assemble all hardware components in a real machine, and check their performance, reliability and stability. It is also very important to build all control software and link to the main frame to see system performance. All experience will provide feedback to 8 GeV XFEL design, whose construction will start in April 2006.

*http://www-xfel.spring8.or.jp

 
 
THESPA01 Before the Big Bang: An Outrageous New Perspective and its Implications for Particle Physics background, LANL, electron, LEFT 2759
 
  • R. Penrose
    Mathematical Institute, Oxford
  The second law of thermodynaics implies that big bang must have been an extraordinarily precisely organized state. What was the geometrical nature of this state? How can we resolve, in any scientific way, the mystery of how such precision came about? In this talk, a novel (and perhaps outrageous) solution is suggested, which involves an examination of what is to be expected of the very remote future of our universe, with its observed accelerated expansion. Some possible observational consequences of the proposal will be indicated, together with some apparent implications for particle physics, some of which are non-standard.  
 
THOAFI02 Ion Instability Observed in PLS Revolver In-vacuum Undulator vacuum, undulator, ion, synchrotron 2771
 
  • H.-S. Kang, J. Choi, M. Kim, T.-Y. Koo, T.-Y. Lee, P.C.D. Park
    PAL, Pohang, Kyungbuk
  Revolver In-Vacuum X-ray Undulator which was designed and fabricated at Spring-8 is under commissioning at PLS. This planar undulator whose permanent magnet array structure is a revolving type with 90-degree step provides 4 different undulator wavelengths of 10, 15, 20, and 24 mm. The minimum gap of the undulator is as small as 5 mm. It was observed that the trailing part of a long bunch train was scraped due to ion instability when the undulator gap was closed below 6 mm. At that time the vacuum pressure in the undulator, which is estimated to be about one order of magnitude lower than that of the undulator gap, increased from 1.4 x 10-10 (gap 20 mm) to 7.9 x 10-10 Torr (gap 6 mm) at the stored beam current of 100 mA. This high vacuum pressure causes fast beam-ion instability: trailing part of a long bunch train oscillates vertically. It was also confirmed that adjusting the orbit along the undulator has improved the situation to some extent. The ion instability measured with a pico-second streak camera and a one-turn BPM as well as the result of orbit adjustment and chromaticity control will be described in this paper.  
slides icon Transparencies
 
THOBFI03 Record-high Resolution Experiments on Comparison of Spin Precession Frequencies of Electron Bunches Using the Resonant Depolarization Technique in the Storage Ring electron, positron, storage-ring, polarization 2787
 
  • S.A. Nikitin, O. Anchugov, V.E. Blinov, A. Bogomyagkov, V.P. Cherepanov, G.V. Karpov, V. Kiselev, E. Levichev, I.B. Nikolaev, A.A. Polunin, E. Shubin, E.A. Simonov, V.V. Smaluk, M.V. Struchalin, G.M. Tumaikin
    BINP SB RAS, Novosibirsk
  The opportunity of performing an experiment on high precision comparison of the electron and positron anomalous magnetic moments following the VEPP-2M experiment is under study at the VEPP-4M storage ring. The record accuracy of 2x10-8 was obtained for comparison of spin precession frequencies in the experiment on resonant depolarization with simultaneously circulating electron bunches, two of them polarized and one unpolarized. It is the first time when the spreading of the spin precession frequency line (~5x10-7,) due to scattering of particle trajectories about the equilibrium orbit in a non-linear field of the storage ring, was presumably observed in experiments. We proposed and realized an RF scheme for controlled separation of the spin precession frequencies of two electron bunches; the first measurements using this scheme were made.  
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THPCH039 Beam Studies with Coherent Synchrotron Radiation from Short Bunches in the ANKA Storage Ring synchrotron, storage-ring, FIR, synchrotron-radiation 2868
 
  • A.-S. Müller, I. Birkel, S. Casalbuoni, B. Gasharova, E. Huttel, Y.-L. Mathis, D.A. Moss, P. Wesolowski
    FZK, Karlsruhe
  • C. J. Hirschmugl
    UWM, Milwaukee, Wisconsin
  In the ANKA storage ring it is possible to store bunches with RMS lengths of the order of 1 ps using a dedicated optics with reduced momentum compaction factor. For short bunch operation a beam energy of 1.3 GeV is chosen as a trade-off between low energy longitudinal instabilities and the increase in natural bunch length with energy. At this medium energy (the energy range of the ANKA storage ring is 0.5 to 2.5 GeV) steady state emission of coherent synchrotron radiation is observed by the ANKA-IR beamline below the threshold current defined by the micro-bunching instability. At lower beam energies where the natural bunch length is significantly shorter, bursts of coherent synchrotron radiation are detected in spite of the longitudinal oscillation. The far infrared spectrum is sensitive to the dynamics of the charge distribution generating the radiation. Measurements of the frequency spectrum of the infrared detector signal add information on bunch dynamics. This paper gives an overview of the studies performed at the ANKA storage ring.  
 
THPCH064 Comparison of Three CSR Radiation Powers for Particle Bunches and Line Charges CSR, synchrotron, synchrotron-radiation, simulation 2931
 
  • K.A. Heinemann, G. Bassi, J.A. Ellison
    UNM, Albuquerque, New Mexico
  We are studying coherent synchrotron radiation (CSR) from arbitrary planar orbits as discussed in another abstract we submitted to EPAC06. It is important to have one-dimensional approximations. Here we report on work constructing and validating such approximations. As part of our work two well known papers by Saldin, Schneidmiller and Yurkov (SSY* are considered which deal with the CSR via a one-dimensional approximation whereby the electron bunch is modelled by a line density. Their one-dimensional approach is important because it is used in various CSR codes and since it serves to some extent as a role model for higher-dimensional models. The present report deals with some general aspects of the work of SSY. In particular, care is taken of the renormalization procedure and of the statistical description in terms of the line density. SSY use a renormalized retarded field whereas the present work uses the radiation field which is defined as half the difference of the retarded and advanced fields. The radiation field came into prominence when Dirac** introduced the Lorentz-Dirac equation.

*E. L. Saldin, et al. Nucl. Instr. Meth. Phys. Res. A 398, 373 (1997) and 417, 158 (1998).**P.A.M. Dirac, Proc. Roy. Soc. (London) A167, 148 (1938).

 
 
THPCH067 Coherent Synchrotron Radiation Studies at the Accelerator Test Facility injection, synchrotron, synchrotron-radiation, CSR 2940
 
  • S. De Santis, J.M. Byrd
    LBNL, Berkeley, California
  • A. Aryshev, T. Naito, J. Urakawa
    KEK, Ibaraki
  • M.C. Ross
    SLAC, Menlo Park, California
  Coherent Synchrotron Radiation (CSR) has been the object of recent experiments and is a topic of great importance for several accelerator currently in their design phase (LCLS, ILC, CIRCE). We present the results of several experimental sessions performed at the Advanced Test Facility - KEK (ATF). An infrared bolometer was used to detect the emitted infrared radiation in the 1-0.05 mm wavelength range as a function of several beam parameters (beam current, RF power, extraction timing, photoinjector laser phase). The beam energy spread was also recorded. We found that the mismatch between injected and equilibrium beam is the source of the coherent signal detected concurrently with the bunch injection.  
 
THPCH072 Wakefields in the LCLS Undulator Transitions LCLS, undulator, SLAC, linac 2952
 
  • K.L.F. Bane
    SLAC, Menlo Park, California
  • I. Zagorodnov
    DESY, Hamburg
  We have studied longitudinal wakefields of very short bunches in non-cylindrically symmetric (3D) vacuum chamber transitions using analytical models and the computer program ECHO. The wake (for pairs of well-separated, non-smooth transitions) invariably is resistive, with its shape proportional to the bunch distribution. For the example of an elliptical collimator in a round beam pipe we have demonstrated that—as in the cylindrically symmetric (2D) case—the wake can be obtained from the static primary field of the beam alone. We have obtained the wakes of the LCLS rectangular-to-round transitions using indirect (numerical) field integration combined with a primary beam field calculation. For the LCLS 1 nC bunch charge configuration we find that the total variation in wake-induced energy change is small (0.03% in the core of the beam, 0.15% in the horns of the distribution) compared to that due to the resistive wall wakes of the undulator beam pipe (0.6%).  
 
THPCH132 EPU Assembly Based on Sub-cassettes Magnetic Characterization undulator, electron, polarization, synchrotron 3107
 
  • G. Tosin, R. Basilio, J.F. Citadini, M. Potye
    LNLS, Campinas
  A procedure to speed up the magnetic field correction of an EPU type undulator is proposed and its results are shown. Such procedure consists in segmenting each one of the four magnetic blocks linear arrays (cassettes) in seven sub-cassettes and making their individual magnetic and mechanical characterization. One theoretical perfect sub-cassette, which is composed of four segments per period in Halbach configuration, is taken as the standard field profile. The peak fields and the fields integrated in each semi-period of one sub-cassette are chosen to be the optimization parameters. The magnetic blocks are displaced (virtual shims) to minimize the difference of the optimization parameters between the sub-cassette magnetic measurement and the standard profile. The sub-cassette magnetic measurements are performed with Hall probes, using the same bench employed in insertion devices characterization.  
 
THPCH135 65 MEV Neutron Irradiation of ND-FE-B Permanent Magnets electron, proton, permanent-magnet, undulator 3116
 
  • X.-M. Maréchal, T. Bizen
    JASRI/SPring-8, Hyogo-ken
  • Y. Asano
    JAEA/SPring-8, Hyogo
  • H. Kitamura
    RIKEN Spring-8 Harima, Hyogo
  Rare-earth permanent magnets are now playing a major role in accelerator technology, from the development of beam transport systems magnets to their extensive use in synchrotron radiation sources and free electron lasers. Unfortunately, operating in a high radiation environment, rare-earth permanent magnets are subject to demagnetization caused by direct and scattered radiation. The lifetime of these components is therefore a major issue: as a result, the number of studies to clarify the demagnetization mechanism or to test materials of interest for a particular application under specific conditions of irradiation has increased in recent years. However, so far, neutron irradiation experiments have been mainly carried out with reactors, were neutrons have a wide, but mainly low, energy spectrum. We present here the results obtained at the TIARA facility of the Japan Atomic Energy Research Institute, a spalliation source of mono highly energetic neutrons. Four types of Nd-Fe-B permanent magnets (Neomax™ 35EH, 32AH, 27VH and 44H) representing a wide range of characteristics (remanence and coervicity) have been studied.  
 
THPCH150 Double-pulse Generation with the FLASH Injector Laser for Pump/Probe Experiments laser, SASE, FEL, polarization 3143
 
  • O. Grimm, K. Klose, S. Schreiber
    DESY, Hamburg
  The injector laser of the VUV-FEL at DESY, Hamburg, was modified to allow the generation of double-pulses, separated by a few cycles of the 1.3 GHz radio-frequency. Such double pulses are needed for driving the planned infrared/VUV pump/probe facility. Construction constraints of the facility will result in an optical path length about 80 cm longer for the infrared. Although the VUV can be delayed using normal-incidence multilayer mirrors at selected wavelengths, a fully flexible scheme is achieved by accelerating two electron bunches separated by more than the path length difference and then combine the infrared radiation from the first with the VUV from the second. This paper explains schemes for the generation of double-pulses with the laser system. It summarizes experimental studies of the effect on the operation of diagnostic instrumentation and on the tunability of the machine. Of special concern is the effect of wakefields on the quality of the second bunch, critical for achieving lasing.  
 
THPCH172 Present Status of Beam Collimation System of J-PARC RCS proton, synchrotron, vacuum, target 3200
 
  • K. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • M. Abe, H. Hanaue, A. Nakamura, Y. Takeuchi
    VIC International Co., Ltd., Tokyo
  • Y. Hirooka, M. Okazaki
    Mitsui Engineering & Shipbuilding Co., Ltd., Tokyo
  The precedence manufacture of the two beam collimator was carried out. In these two sets, we tested the heat transfer capacity of cooling fins and remote clamp handling system. The vertical collimator was able to keep temperature under 120 degrees C by the design heat 400W, but in case of the horizontal collimator, it went over 200 degrees C by the design heat 700W. The design was changed towards adding an air duct. About remote clamp handling system, it checked that it could attach by the He leak below 5.*10-10Pa m3/sec as a result of the helium leak examination.  
 
THPLS001 The Strict Solution of a Radiation Problem in Toroidal Cavity synchrotron, synchrotron-radiation, plasma, electromagnetic-fields 3260
 
  • T.H. Harutunyan
    YSU, Yerevan
  • E.D. Gazazyan, M.K. Khojoyan
    YerPhI, Yerevan
  The radiation of charged particles bunch which is moving along the axes of toroidal cavity cross section is considered. The toroidal cavity has a finite value of the quality factor and is filled with special symmetry inhomogeneous dielectric medium. The problem's solution is based on the complete set of the toroidal cavity's own modes being defined strictly for the mentioned dielectric medium the cavity is filled with. The charged particles bunch exists in the cavity during a finite time period and the charged bunch's arising and vanishing effects are examined and are taken into account as well. The toroidal cavity is considered as a convenient model to investigate the electromagnetic properties of the tokamak system, using the defined modes.  
 
THPLS015 Spectral Fingerprints of Femtoslicing in the THz Regime electron, laser, resonance, undulator 3302
 
  • K. Holldack, S. Khan, T. Quast
    BESSY GmbH, Berlin
  • R. Mitzner
    Universität Muenster, Physikalisches Institut, Muenster
  Femtosecond (fs) THz pulses are observed as a consequence of laser-induced energy modulation of electrons in the BESSY II storage ring in order to generate fs x-ray pulses via femtoslicing*. The THz pulses are spectrally characterized by step-scan and rapid scan FTIR spectroscopy. The temporal shape of the laser-induced density modulation is reconstructed from the THz spectra. It is studied as a function of laser and storage ring parameters and monitored over several revolutions. The results are compared with numerical simulations. The THz spectra acquired over a few seconds are used to optimize the laser parameters for achieving minimum x-ray pulse lengths in femtoslicing experiments.

*A. Zholents and M. Zoloterev, PRL 76 (1996), 912.

 
 
THPLS016 Bunch Shape Diagnostics Using Femtoslicing laser, electron, CSR, undulator 3305
 
  • K. Holldack, T. Quast
    BESSY GmbH, Berlin
  • S. Khan
    Uni HH, Hamburg
  • R. Mitzner
    Universität Muenster, Physikalisches Institut, Muenster
  Laser-energy modulation of relativistic electron bunches as needed for the BESSY femtosecond (fs) x-ray source is accompanied by the emission of fs THz pulses*. The total THz intensity probes the square of the longitudinal particle density within a slice of ~50 fs length (fwhm). The bunch shape can be directly monitored while sweeping the time delay between laser and bunch clock. The method is demonstrated for bunch lengths between 3 and 30 ps (rms) in different operation modes of BESSY II. The use of THz signals from successive turns and the influence of periodic bursts of coherent synchrotron radiation, which lock to the laser pulse under certain conditions, are discussed. The method is used for setting up and stabilizing the temporal overlap between a fs-laser and a relativistic electron bunch.

*K. Holldack et al., Phys. Rev. Lett. (2006), accepted Dec. 2005.

 
 
THPLS018 FLUKA Calculations of Neutron Spectra at BESSY target, shielding, electron, vacuum 3311
 
  • K. Ott
    BESSY GmbH, Berlin
  The synchrotron light source BESSY consists of a 50 MeV microtron, a full energy synchrotron and a 1.9 GeV storage ring. The electron losses during injection causes electromagnetic cascades within the stainless steel of the vacuum system and the aluminum chambers of the undulators. The cascade-produced neutrons result from giant resonances, quasi-deuteron fissions and photo-pion productions. The cross sections of the evaporation reactions of neutrons are an order of magnitude higher than the cross sections of the latter two reaction channels. The energy distribution of the giant resonance neutrons has a maximum at about 1 MeV in comparison with 100 - 200 MeV of the high energy neutrons. At electron accelerators outside the shielding wall, half of the neutron dose is often determined by the more penetrating high energy part of the neutron fluence. We used the particle interaction and transport code FLUKA for the calculations of the energy distribution of both the fluence and the dose inside and outside the shielding wall for different realistic scenarios. From the integrated spectra we get the calibration factor to determine the total neutron dose from the measurements directly.  
 
THPLS019 The Metrology Light Source: an Electron Storage Ring Dedicated to Metrology electron, storage-ring, photon, synchrotron 3314
 
  • R. Klein, G. Ulm
    PTB, Berlin
  • P. Budz, K. Buerkmann-Gehrlein, J. Rahn, G. Wuestefeld
    BESSY GmbH, Berlin
  PTB, the German National Metrology Institute, in close cooperation with BESSY, is currently setting up a low-energy electron storage ring (200 MeV up to 600 MeV electron energy), the Metrology Light Source MLS, which will be dedicated to metrology and technology development in the UV and EUV spectral range which synchrotron radiation. The MLS has been designed by BESSY according to PTB specifications. User operation is scheduled to begin in 2008. Currently, the building, housing the storage ring, is nearly completed, and all major parts of the storage ring and the injection system have been ordered or have already been delivered. The MLS will be equipped with all the instrumentation necessary to measure the storage ring parameters needed for the calculation of the spectral photon flux according to the Schwinger theory with low uncertainty, enabling PTB to operate the MLS as a primary source standard. Moreover, calculations show, that the MLS is ideally suited for the production of coherent synchrotron radiation in the far IR and THz region. We give a status update on the construction, the instrumentation for the measurement of the storage ring parameters and calculations for a low-  
 
THPLS022 Radiation Dose Related to ANKA Operation Mode storage-ring, optics, emittance, injection 3323
 
  • I. Birkel, MH. Hagelstein, E. Huttel, A.-S. Müller, P. Wesolowski
    FZK, Karlsruhe
  Radiation doses in the ANKA hall are measured by area monitoring and Albedo dosimeters. In August 2004 the machine optics was replaced by a new optics with reduced emittance and higher brightness. Measurements of the beam lifetime and the related radiation doses show a strong correlation between the operation mode of the machine and the dose distribution in the hall.  
 
THPLS026 Front Ends at Diamond undulator, multipole, wiggler, storage-ring 3335
 
  • J. Strachan, D.G. Clarke
    CCLRC/DL, Daresbury, Warrington, Cheshire
  • H.C. Huang, J. Kay
    Diamond, Oxfordshire
  This paper describes the three different types of Front End that have been designed to transmit the intense synchrotron radiation generated by the undulator, multi-pole wiggler and bending magnet sources in the Diamond storage ring to the experiments. The functions of the main components and their location in the layout are described. The Finite Element Analysis that has been carried out to verify the performance under the high heat loads generated by Diamond is also described along with the limits on temperature and stress that have been employed in the design.  
 
THPLS037 Beam Position and Angular Monitor for Undulator by Using SR Monitor Technique electron, undulator, focusing, injection 3368
 
  • T. Mitsuhashi, M. Tadano
    KEK, Ibaraki
  We presented a beam position monitor by using SR monitor technique in the last PAC05. In this monitor, a visible SR in far tail of the undulator spectrum is extracted by a water-cooled beryllium mirror. We applied a focusing system to observe a beam position in the undulator through an optical image of beam. We continue further study of this monitor, and this time, we add the afocal system like a Kepler type telescope to measure the angular deviation of the beam. This system converts the angular deviation of optical axis of input ray into position deviation, and we can measure an angular deviation of the beam through its position deviation on the CCD. The results show us this method is applicable to monitor an angular deviation of beam in the undulator independent from position deviation, and gap change of undulator has no effect for the beam position monitoring.  
 
THPLS041 Observation of Intense Terahertz Synchrotron Radiation produced by Laser Bunch Slicing at UVSOR-II laser, electron, CSR, synchrotron 3377
 
  • M. Katoh, M. Hosaka, K. Kimura, A. Mochihashi, M. Shimada
    UVSOR, Okazaki
  • T. Hara
    RIKEN Spring-8 Harima, Hyogo
  • T. Takahashi
    KURRI, Osaka
  • Y. Takashima
    Nagoya University, Nagoya
  We have performed electron bunch slicing experiments using a femto-second high power pulse laser in the UVSOR-II electron storage ring. As the pulse laser system we have used a Ti:Sa laser whose wavelength is 800 nm, typical pulse duration is 100 fs, pulse repetition is 1 kHz and typical average power is 2W. The laser is operated in mode-locked condition and synchronized with the electron beam revolution. The laser pulse is injected into an undulator section and it goes along with the electron bunch. By adjusting the radiation wavelength of the undulator to the laser wavelength, the electron beam energy can be partially modulated in the electron bunch. We have observed THz synchrotron radiation (SR) light from a bending magnet that is downstream of the interaction region. The SR light contains extremely intense THz pulse radiation that is synchronized with the laser injection. The extremely high intensity strongly suggests that the THz pulses are coherent synchrotron radiation from the electron bunch with a hole because of the laser-beam interaction.  
 
THPLS042 Observation of THz Synchrotron Radiation Burst in UVSOR-II Electron Storage Ring synchrotron, electron, synchrotron-radiation, CSR 3380
 
  • A. Mochihashi, M. Hosaka, M. Katoh, K. Kimura, M. Shimada
    UVSOR, Okazaki
  • T. Takahashi
    KURRI, Osaka
  • Y. Takashima
    Nagoya University, Nagoya
  Very intense THz synchrotron radiation bursts have been observed in single-bunch operation in the UVSOR-II electron storage ring*. The observation was performed in an infrared beam line in UVSOR-II by using a liquid-He-cooled In-Sb hot-electron bolometer that has a good response time of several microseconds. Thanks both to the beam line and the detector, it is clearly observed that the intense bursts have typical macroscopic and microscopic temporal structure. Macroscopically, it is clearly observed that the bursts tend to be generated with quasi-periodic structure in which the period tends to depend on the beam intensity. From a microscopic point of view, each burst has also quasi-periodic structure in itself, and the period almost corresponds to the half value of the inverse of the synchrotron oscillation frequency. The peak intensity of the bursts was about 10000 times larger than that of ordinary synchrotron radiation in the same wavelength region. The extremely high intensity strongly suggests that the bursts are coherent synchrotron radiation, although the radiation wavelength was much shorter than the electron bunch length.

*Y. Takashima et al., Jpn. J. Appl. Phys. 44, No.35 (2005) L1131.

 
 
THPLS056 Synchrotron Radiation Monitors at ALBA synchrotron, synchrotron-radiation, booster, vacuum 3410
 
  • U. Iriso
    CELLS, Bellaterra (Cerdanyola del Vallès)
  • F. Pérez
    ALBA, Bellaterra
  ALBA is a 3 GeV, low emittance third generation synchrotron light source that is in the construction phase in Cerdanyola, Spain. Synchrotron Radiation Monitors (SRM) are one of the most useful, non-destructive tools to easily obtain information of three important parameters for a synchrotron user: beam position, beam dimensions and beam stability. These monitors diagnose beam performance using the radiation produced when the beam traverses a bending magnet. An extensive usage of SRM, based on the visible part of the spectrum, is planned in the ALBA synchrotron: Linac, Booster, Transfer Lines and the Storage Ring. The latter will be equipped as well with an SRM based on the x-ray part of the spectrum, using the PinHole technique in order to accurately measure the low beam size and emittance. This paper describes the different SRM designs for the ALBA light source.  
 
THPLS059 Status of the MAX IV Light Source Project undulator, storage-ring, linac, electron 3418
 
  • M. Eriksson, M. Berglund, K.I. Blomqvist, M. Brandin, T. Hansen, D. Kumbaro, L.-J. Lindgren, L. Malmgren, M. Sjöström, H. Svensson, H. Tarawneh, S. Thorin, E.J. Wallén, S. Werin
    MAX-lab, Lund
  • B. Anderberg
    AMACC, Uppsala
  The present development of the accelerator part of the MAX IV synchrotron radiation project is presented. The main features of the 3 GeV injector linac and the two storage rings operated at different electron energies to cover a broad spectral range of high brilliance undulator radiation are described in some detail. A third ring, the existing MAX III ring, is planned to be transferred to the new facility. The preparation of the injector linac to serve as a free electron laser source and the major sub-systems of the facility are also presented.  
 
THPLS076 Status of RF Deflecting Cavity Design for the Generation of Short X-Ray Pulses in the Advanced Photon Source Storage Ring damping, storage-ring, impedance, KEK 3460
 
  • G.J. Waldschmidt, M. Borland, Y.-C. Chae, K.C. Harkay, D. Horan, A. Nassiri
    ANL, Argonne, Illinois
  The Advanced Photon Source (APS) at Argonne National Laboratory is exploring the possibility of using radio frequency deflection to generate x-ray radiation pulses on the order of 1 pico-second (Delta t - 70%) or less*. This scheme is based on a proposal by A. Zholents et al.** that relies on manipulating the transverse momenta of the electrons in a bunch by using an rf deflecting cavity to induce a longitudinally dependent vertical deflection of the beam. The beam will then travel through a number of undulators before arriving at a second set of deflecting cavities where the deflection is reversed such that the remainder of the storage ring is largely unperturbed***. Considerable effort has been expended on the design of a superconducting rf deflecting cavity operating in the S-Band at 2.8 GHz to address fundamental design issues including cavity geometry, deflecting voltage, rf power coupling, tuning, and damping of higher-order and lower-order modes. In this paper we present simulation results and analysis of an optimized superconducting rf deflecting cavity design for the APS storage ring.

*K. Harkay et al. Proceedings of 2005 PAC, Knoxville, TN, May 2005, p. 668. **A. Zholents et al. Nucl. Instrum. Methods, A425, 385 (1999). ***M. Borland and V. Sajaev. Proceedings of 2005 PAC, Knoxville, TN, May 2005, p. 3886.

 
 
THPLS082 Status of the Top-off Upgrade of the ALS injection, brightness, storage-ring, undulator 3469
 
  • C. Steier, D. Robin, T. Scarvie
    LBNL, Berkeley, California
  In order to provide higher brightness and better stability, the ALS is being upgraded to top-off injection. One main part of the top-off modifications is an upgrade of the booster as well as extraction and injection elements and the transfer line for full energy. Further upgrades include new diagnostics, improved controls and timing system, and new radiation safety systems (monitors and interlocks).  
 
THPLS109 Measurements and Diagnostics on the MAX Recirculator electron, linac, FEL, injection 3532
 
  • M. Brandin, B. Nelander, S. Werin
    MAX-lab, Lund
  The MAX Recirculator is a unique accelerator, a two-pass linac at 500 MeV, that operates as injector for three storage rings. Here are presented some discussions on measurments of beam parameters such as emittance, energy spread, and bunch length. We describe what measurements are done, by wich methods, results, and how they can be improved. Also, we make an analysis of What methods and hardware are needed to perform the measurements that can't be done with the equipment in place today.  
 
THPLS122 Investigations of the Thermal Beam Load of a Superconducting In-vacuum Undulator undulator, vacuum, synchrotron, synchrotron-radiation 3568
 
  • S. Casalbuoni, MH. Hagelstein, B.K. Kostka, R. Rossmanith
    FZK, Karlsruhe
  • T. Baumbach, A. Bernhard, D. Wollmann
    University of Karlsruhe, Karlsruhe
  • E. Steffens, M. Weisser
    Erlangen University, Erlangen
  Both the resistive wall effect and the synchrotron radiation~\cite{wallen, casalbuoni, chou} can warm up the cold bore of a superconductive in-vacuum undulator. For the in ANKA installed superconducting undulator measurements showed that the dominant heat load contribution comes from the synchrotron radiation generated in the upstream bending magnet: 1 W per 100 mA stored current at a beam energy of 2.5 GeV and an undulator gap of 8 mm.  
 
THPLS124 The Second Generation of Superconductive Insertion Devices for ANKA undulator, wiggler, insertion, insertion-device 3574
 
  • A. Bernhard, T. Baumbach, D. Wollmann
    University of Karlsruhe, Karlsruhe
  • S. Casalbuoni, MH. Hagelstein, R. Rossmanith
    FZK, Karlsruhe
  • T. Schneider
    FZ Karlsruhe, Karlsruhe
  • F. Schoeck, E. Steffens, M. Weisser
    University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
  After the superconducting undulator SCU14 was installed and successfully started operation at ANKA in spring 2005, a second generation of superconducting insertion devices for ANKA is under development. The ANKA soft x-ray analytics beamline WERA is planned to be equipped with a superconducting elliptically polarising undulator (SCEPU) with electrically tunable polarisation, and a superconducting combined undulator/wiggler (SCUW) capable of period tripling will serve as the source for the planned ANKA imaging beamline. In this paper the studies on the ANKA superconducting EPU and the status of the SCUW-project will be reviewed.  
 
THPLS132 Physics Requirement of a PLS-XFEL Undulator undulator, SASE, FEL, XFEL 3592
 
  • D.E. Kim, C.W. Chung, I.S. Ko, J.-S. Oh, K.-H. Park
    PAL, Pohang, Kyungbuk
  Pohang Accelerator Laboratory(PAL)is planning a 0.3nm SASE (Self Amplification of Spontaneous Emission) XFEL based on a 3.7GeV linear accelerator. For short saturation length, application of the SPring8 type in the vacuum undulator is needed. This reflects the experiences from the Spring8 SCSS project. The end structures were designed to be asymmetric along the beam direction to ensure systematic zero 1st field integral. The thickness of the last magnets was adjusted to minimize the transition distance to the fully developed periodic field. This approach is more convenient to control than adjusting the strength of the end magnets. The final design features 4mm minimum pole gap, 15mm period, and peak effective field of 1.09 Tesla. In this article, the physical design of the undulator, the design of the end structure, and the physics requirements of the undulator system will be presented.  
 
THPLS133 Simulations of Electromagnetic Undulator for Far Infrared Coherent Source of TTF at DESY undulator, electron, FIR, simulation 3595
 
  • E. Syresin, V.V. Borisov, E.A. Matushevsky, N.A. Morozov
    JINR, Dubna, Moscow Region
  • O. Grimm, M.V. Yurkov
    DESY, Hamburg
  • J. Rossbach
    Uni HH, Hamburg
  A perspective extension of the VUV FEL user facility at DESY is infrared coherent source on the base of electromagnetic undulator. The undulator consists of 9 periods, period length is 40 cm long, and peak magnetic field is up to 1.2 T. With the energy of electron beam of 500 MeV maximum radiation wavelength is about 200 mkm. An important feature of the beam formation system of the VUV FEL is the possibility to produce ultra-short, down to 50 mkm rms electron bunches. Such short bunches produce powerful coherent radiation with multi-megawatt power level. FIR coherent source operates in a parasitic mode utilizing electron beam passed VUV undulator. Generation of two-colors by a single electron bunch reveals unique possibility to perform pump-probe experiments with VUV and FIR radiation pulses. In this report we present simulations of the undulator magnetic system and beam dynamics.  
 
THPLS134 A General View of IDs to be Installed at ALBA on Day One undulator, wiggler, polarization, ELETTRA 3598
 
  • J. Campmany, F. Becheri, D. Bertwistle, D. Einfeld, J. Marcos, V. Massana
    ALBA, Bellaterra
  • Z. Martí
    LLS, Bellaterra (Cerdanyola del Vallès)
  The new 3rd generation synchrotron radiation source ALBA to be built nearby Barcelona is planned to start operation in 2009 with several different insertion devices installed in the storage ring either from "day one" or within the first year of operation. The list of high-priority insertion devices includes: 2 planar PPM SmCo in-vacuum undulators with the period of 21.3 mm; 2 Apple-II type PPM NdFeB undulators with the period of 71 mm; 1 superconducting planar wiggler with the period of 30 mm and a maximum field of 2 T, and a 1 conventional wiggler with the period of 65 mm and a maximum field of 1.55 T. The emission of these undulators covers wide spectral range extending from hard X-rays to UV. Pre-design of the IDs was done by ALBA. The construction will be done by industrial companies and institutions with production capabilities. ALBA will set up a magnetic measurement laboratory for the acceptance tests. The paper will present peculiarities of the magnetic design, calculated maximum-flux spectra and associated heat load in various modes of operation.  
 
THPLS137 Insertion Devices for the MAX IV Light Source undulator, storage-ring, insertion, insertion-device 3607
 
  • E.J. Wallén, K.I. Blomqvist, B. N. Jensen, U. Johansson
    MAX-lab, Lund
  The foreseen insertion devices and expected brilliance for the MAX IV light source are presented. The planned MAX IV light source consists of three low emittance storage rings and a 3 GeV linac. The linac is used as a full energy injector. The three storage rings will be operated at 700 MeV, 1.5 GeV, and 3.0 GeV, which makes it possible to cover a large spectral range from IR to hard X-rays with insertion devices optimised for each storage ring.  
 
FRYBPA01 Overview of Single Pass Free Electron Lasers electron, FEL, laser, undulator 3636
 
  • C. Pellegrini
    UCLA, Los Angeles, California
  The presentation will cover world wide status of single pass free electron lasers. A general status will be given of the projects. Common themes will be discussed, as will the challenges of these themes. Unique characteristics of individual projects will also be covered. Here the emphasis will be on a description of novel and challenging techniques: for example examples seeding of the FEL, different types of guns for high brightness electron beam production, very short or very long pulse production, etc.  
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