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

radiation

                        
Paper Title Other Keywords Page
MOPKF004 Magnet Sorting Algorithm Applied to the LNLS EPU undulator, polarization, wiggler, permanent-magnet 303
 
  • X.R. Resende, R.M. Dias
    LNLS, Campinas
  The Brazilian Synchrotron Light Laboratory is about to begin the construction of the first Undulator for its 1.37 GeV electron storage ring. This device will be of the EPU type with a period of 50 milimeters and 22 milimeters minimum magnetic gap. In this work we report on the sorting algorithm applied in the construction of a 10-period undulator prototype.  
 
MOPKF011 Output Variability of the BESSY Soft X-ray FEL bunching, electron, undulator, simulation 321
 
  • A. Meseck, M. Abo-Bakr, B.C. Kuske
    BESSY GmbH, Berlin
  The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generation HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral rang(0.02 keV - 1 keV). A photoinjector and a superconducting $2.3\,GeV$ CW linac will feed three independent HGHG-FEL-lines. Depending on the optimisation criteria, it is possible to obtain either maximum output power or pure spectrum from the same HGHG-line. We present simulation studies for the BESSY-HGHG-FELs and discuss the possible variability of the output performance.  
 
MOPKF012 A 7T Multipole Wiggler in BESSY II: Implementation and Commissioning Results wiggler, vacuum, optics, dynamic-aperture 324
 
  • E. Weihreter, J. Feikes, P. Kuske, R. Müller, G. Wustefeld
    BESSY GmbH, Berlin
  • D. Berger
    HMI, Berlin
  • N.A. Mezentsev, V. Shkaruba
    BINP SB RAS, Novosibirsk
  To generate hard X-ray beams for residual stress analysis and for magnetic scattering with the BESSY II SR source, a 7T wiggler with 17 poles has been implemented. Several problems had to be solved. Wake fields induced by smaller steps in the geometry of the radiation shield inside the beam chamber led to intolerable LHe consumption, which have been analysed numerically and then cured by improving the shield geometry. Much of the routine operation procedures are influenced by the unusually high radiation power level of max. 55 kW. For system protection an interlock system dumps the electron beam automatically in case of relevant error events. This wiggler is by far the strongest perturbation of the linear beam optics, breaking seriously the symmetry of the ring. Beam optical parameters including tune shift and beta beat have been measured to quantify these perturbations and develop efficient cures to limit the negative effects on beam lifetime and dynamic aperture. So far the wiggler is operated at 2.8 T and max. currents up to 250 mA in normal user shifts.  
 
MOPKF030 "ARC-EN-CIEL" a Proposal for a 4th Generation Light Source in France laser, gun, electron, linac 366
 
  • M.-E. Couprie, D. Garzella, B. Gilquin, P. Monot, L. Nahon
    CEA/DSM, Gif-sur-Yvette
  • O.V. Chubar, A. Loulergue
    SOLEIL, Gif-sur-Yvette
  • M. Desmons, M. Jablonka, F. Meot, A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • J.-R. Marquès
    LULI, Palaiseaux
  • J.-M. Ortega
    LURE, Orsay
  • A. Rousse
    LOA, Palaiseau
  An accelerator based 4th generation source is proposed to provide the user community with coherent femtosecond light pulses in the UV to X ray range. The project is based on a CW 700 MeV superconducting linac delivering high charge, subpicosecond, low emittance electron bunches with high repetition rate. This facility allows for testing High Gain Harmonic Generation seeded with high harmonics in gases, as well as the standard SASE mode, covering a spectral range down to 0.8 nm and 5 nm respectively. In addition, two beam loops are foreseen to increase the beam current in using the energy recovery technique. They will accommodate undulators for the production of femtosecond synchrotron radiation in the IR, VUV and X ray ranges together with a FEL oscillator in the 10 nm range.  
 
MOPKF031 SOLEIL Insertion Devices: The Progress Report undulator, insertion, insertion-device, polarization 369
 
  • O.V. Chubar, C. Benabderrahmane, A. Dael, M.-P. Level, O. Marcouillé, M. Massal
    SOLEIL, Gif-sur-Yvette
  The French national synchrotron radiation source SOLEIL is planned to start operation in 2006 with several different insertion devices installed in the storage ring either from "day one" or within the first year. The list of high-priority insertion devices includes: 3 planar hybrid in-vacuum undulators with the period of 20 mm; 3 Apple-II type PPM undulators with the period of 80 mm; 3 electromagnet elliptical undulators with the period of 256 mm, and a 640 mm period elliptical electromagnet undulator offering advanced possibilities for fine-tuning of polarization states of the emitted radiation. The emission of all these undulators is covering wide spectral range extending from hard X-rays to UV. Pre-design of the IDs was done by SOLEIL. The construction will be done by industrial companies and institutions with production capabilities. Magnetic assembly of the Apple-II and in-vacuum undulators is planned to be done in collaboration with ELETTRA and ESRF. The final magnetic measurements of all the IDs will be made in the SOLEIL magnetic measurements laboratory. The paper will present peculiarities of the magnetic design, calculated maximum-flux spectra and associated heat load in various modes of operation.  
 
MOPKF032 Status of the ESRF Insertion Devices undulator, insertion, insertion-device, photon 372
 
  • J. Chavanne, C. Penel, B. Plan, F. Revol
    ESRF, Grenoble
  The ESRF insertion devices are the object of a continuous refurbishment in order to follow the changing needs of the beamlines and increase their performances. The successful development of the narrow aperture aluminum chambers pumped by non evaporable getter has resulted in the reduction of the minimum gap from 16 mm to 11 mm . A new set of undulator magnetic assemblies with shorter magnetic periods are being prepared that make use of the lower gap. .A prototype of a new type of revolver undulator support has been completed and successfully tested. Such a structure allows the beamline user to switch between two different undulator periods in less than a minute. Three additional devices will be constructed in 2004. Three new in-vacuum undulators have been installed on the ring. One of them is based on an hybrid magnetic structure and achieves a peak field 20% higher than a pure permanent magnet undulator of identical period. Their main magnetic measurements results and interactions with the stored beam are presented.  
 
MOPKF034 Status of the Development of Superconducting Undulators at the ESRF undulator, storage-ring, vacuum, synchrotron 378
 
  • E.J. Wallén, J. Chavanne, P. Elleaume
    ESRF, Grenoble
  This note describes the present status of the development of superconducting undulators at the ESRF. Magnetic models of superconducting undulators suitable for the ESRF storage ring have been developed and evaluated. The superconducting undulators studied are horizontally polarizing undulators with a flat field profile and the vertical physical aperture of the undulator is 6 mm. Both 2D models of the local field in a period of the undulator and 3D models of the complete superconducting undulator, including the end sections and current leads, have been evaluated. The practical limit for the obtainable magnetic field has been estimated from the known performance of superconducting wire available from the cabling industry. This note also describes the conceptual design of the cryostat of the superconducting undulator and estimations of the expected heat load to the cryostat at different filling modes of the storage ring.  
 
MOPKF037 FERMI@ELETTRA: 100 nm - 10 nm Single Pass FEL User Facility linac, undulator, electron, laser 387
 
  • R.J. Bakker, C. Bocchetta, P. Craievich, G. D'Auria, M. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, G. Pangon, L. Rumiz, L. Tosi, V. Verzilov, D. Zangrando
    ELETTRA, Basovizza, Trieste
  The FERMI@ELETTRA project is an initiative from ELETTRA, INFM and other Italian institutes, to construct a single-pass FEL user-facility for the wavelength range from 100 nm (12 eV) to 10 nm (124 eV), to be located next to the third-generation synchrotron radiation facility ELETTRA in Trieste, Italy. The project is concentrated around the existing 1.2-GeV S-band linac, i.e., the injector for the storage ring. Presently the linac is only operational for approximately 2 hours per day. The remaining time is available for the construction and operation of an FEL but modifications and operation must be planned such that operation of the storage ring can be guaranteed until the completion of a new full-energy injector (spring 2006). At this moment the FEL project evolves from a conceptional design stage towards a technical design and the actual implementation. Key issues are: incorporation of the free-electron laser in the infrastructure of the Sincrotrone Trieste, adjustments of the linac to facilitate FEL operation, required additional civil engineering, undulator design, FEL seeding options, and beamline design. This paper serves as an overview of the project in combination with a discussion of the critical issues involved.  
 
MOPKF050 Current Heart-like Wiggler wiggler, undulator, free-electron-laser, plasma 423
 
  • V.I.R. Niculescu, G.R. Anda, F. Scarlat
    INFLPR, Bucharest - Magurele
  • V. Babin
    INOE, Bucharest
  • C. Stancu, A. Tudorache
    Bucharest University, Faculty of Physics, Bucharest-Magurele
  A new wiggler structure for free electron lasers is presented. Current hart-like wiggler produced magnetic fields which were spatially periodic. The current wiggler structure was in the shape of stacks of modified circle wires. The current had alternating directions. The magnetic field components for each wire present a C2 symmetry (for a model with 3 branches). The wiggler transverse cross - section in arbitrary units was given by the following expressions: x = R(d+sin(3j))cos(j) , y = R(d+sin(3j))sin(j) , z = constant, where d and R are the parameters. In cylindrical coordinates the Biot - Savart law was evaluated numerically. The magnetic field aspect was mainly transversal and also easily adjusted with the current . The versatility of this structure permits new geometrical forms and developments in the wiggler and wiggler design .  
 
MOPKF053 Pulsed-wire Method of Field Measurement on Short Elliptically Polarized Undulator undulator, synchrotron, alignment, polarization 428
 
  • T.-C. Fan, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  With two sets of photo illuminator and detector, scientists already have applied pulsed-wire method to measure the magnetic field along two mutually perpendicular directions. Two-dimensional pulsed-wire method is useful for the test of elliptically polarlized undulator (EPU). We tried to use this method to observe the first integral and second integral fields of a short EPU in real time during the polarization tuning. We have taken care more details than the pulsed-wire measurement of planner undulators. The phase difference, the relative field strength along two direction as well as the precise centerline can be achieved.  
 
MOPKF054 Generation of Femtosecond Electron Pulses electron, cathode, simulation, linac 431
 
  • S. Rimjaem, V. Jinamoon, K. Kusoljariyakul, J. Saisut, C. Thongbai, T. Vilaithong
    FNRF, Chiang Mai
  • S. Chumphongphan
    Mae Fah Luang University, Chiang Rai
  • M.W. Rhodes, P. Wichaisirimongkol
    IST, Chiang Mai
  • H. Wiedemann
    SLAC/SSRL, Menlo Park, California
  Femtosecond electron pulses have become an interesting tool for basic and applied applications, especially in time-resolved experiments and dynamic studies of biomolecules. Intense, coherent radiation can be generated in a broad far-infrared spectrum with intensities, which are many orders of magnitude higher than conventional sources including synchrotron radiation sources. At the Fast Neutron Research Facility (FNRF), Chiangmai University (Thailand), the SURIYA project has been established with the aim to produce femtosecond pulses utilizing a combination of a S-band thermionic rf-gun and an alpha-magnet as the magnetic bunch compressor. A specially designed rf-gun has been constructed to obtain the optimum beam characteristics for best bunch compression. Simulation results show that the bunch lengths as short as 50 fs rms can be expected at the experimental station. This rf- gun, an alpha-magnet and a 20 MeV linac with beam transport system were installed and are being commissioned to generate femtosecond electron bunches. To measure the bunch length of the electron pulses, a Michelson interferometer will be used to observe the spectrum of coherent FIR transition radiation via optical autocorrelation. The main results of numerical simulations and experimental results will be discussed in this paper.  
 
MOPKF055 A Study of CSR Induced Microbunching Using Numerical Simulations dipole, simulation, synchrotron, synchrotron-radiation 434
 
  • M.A. Bowler, H.L. Owen
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Microbunching due to Coherent Synchrotron Radiation (CSR) has been predicted for high density bunches and has been 'observed' using numerical simulations by the code ELEGANT of M. Borland, which includes a 1D model of CSR. However, there is currently a debate as to whether this micro-bunching is a real physical effect or is a numerical artefact, possibly introduced by having to use macro-particles to model the electrons. In particular, the amplitude of the micro-bunching diminishes as the number of macroparticles increases, but the question remains open as to whether the amplitude converges to zero or a finite value. The micro-bunching produced by ELEGANT is being studied as a function of the numerical parameters of the code and also as a function of the range of bunch parameters and bending magnet strengths of relevance to the 180 degree bending arcs required for the proposed 4GLS at Daresbury Laboratory. Calculations with up to 2 million macroparticles have been carried out on a Linux workstation using gaussian bunches of FWHM of 2psec and charge of 1 nC, and show the existence of microbunching at the end of a 180 degree arc containing 5 TBA cells with magnet strengths of 0.5T. Further investigation of this problem is required.  
 
MOPKF058 Construction of an APPLE-II Type Undulator at Daresbury Laboratory for the SRS undulator, vacuum, insertion-device, coupling 440
 
  • F.E. Hannon, J.A. Clarke, C. Hill, A.A. Muir, D.J. Scott, B.J.A. Shepherd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  A new variable polarisation undulator of the APPLE-II type has been designed and constructed at Daresbury Laboratory. Testing of the 56mm period device has recently started in the new Magnet Test Facility at Daresbury Laboratory. This paper presents the magnetic and mechanical design of the undulator, and the first magnetic measurement results.  
 
MOPKF072 Towards Attosecond X-ray Pulses from the FEL electron, laser, wiggler, lattice 482
 
  • A. Zholents, J.M. Byrd, W. Fawley, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, M. Venturini, M.S. Zolotorev
    LBNL, Berkeley, California
  The ability to study ultrafast phenomena has been recently advanced by the demonstrated production and measurement of a single, 650-attosecond, soft x-ray pulses precisely synchronized to the pump laser pulse consisted of just few optical cycles. The next frontier is a production of attosecond x-ray pulses at even shorter wavelengths. Here we propose the method of ?seeded attosecond x-ray radiation? where an isolated, attosecond duration, short-wavelength x-ray pulse is radiated by electrons selected by their previous interaction with a few-cycle, intense laser pulse. In principle this method allows excellent synchronization between the attosecond x-ray probe pulse and a pump source that can be the same few-cycle laser pulse or another signal derived from it.  
 
MOPKF074 Harmonic Cascade FEL Designs for LUX laser, undulator, electron, simulation 488
 
  • G. Penn, J.N. Corlett, W. Fawley, M. Reinsch, W. Wan, J.S. Wurtele, A. Zholents
    LBNL, Berkeley, California
  LUX is a proposed facility for ultrafast X-ray science, based on an electron beam accelerated to GeV energies in a recirculating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 190–250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after entering a second, differently tuned undulator. Repeated stages in a cascade yield increasing photon energies up to 1 keV. Most of the undulators in the cascade operate in the low-gain FEL regime. Harmonic cascades have been designed for each pass of the recirculating linac up to a final electron beam energy of 3.1 GeV. For a given cascade, the photon energy can be selected over a wide range by varying the seed laser frequency and the field strength in the undulators. We present simulation results using the codes GENESIS and GINGER, as well as the results of analytical models which predict FEL performance. We discuss lattice considerations pertinent for harmonic cascade FELs, as well as sensitivity studies and requirements on the electron beam.  
 
MOPKF077 Reducing the Synchrotron Radiation on RF Cavity Surfaces in an Energy-recovery Linac synchrotron, synchrotron-radiation, electron, linac 494
 
  • G. Hoffstaetter, M. Liepe, T. Tanabe
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  In Energy Recovery Linac (ERL) light sources, a high energy, high current beam has to be bend into a superconducting linac to be decelerated. The synchrotron radiation produced in the last bending magnet before the linac shines into the superconducting structures if not collimated appropriately. Due to the length of the linac, the radiation cannot be completely guided through the superconducting structure, as in existing SRF storage rings. For the example of an ERL extension to the existing CESR storage ring at Cornell we estimate the magnitude of this problem by quantifying the heat load that can be accepted on a superconducting surface and by analyzing how much radiation is deposited on the cavity surfaces for different collimation schemes.  
 
MOPLT013 Fatigue Testing of Materials by UV Pulsed Laser Irradiation laser, linac, simulation, vacuum 557
 
  • S. Calatroni, H. Neupert, M. Taborelli
    CERN, Geneva
  The energy dissipated by the RF currents in the cavities of high-power pulsed linacs induces cycles of the surface temperature. In the case of the CLIC main linac the expected amplitude of the thermal cycles is about hundred degrees, for a total number of pulses reaching 10e11. The differential thermal expansion due to the temperature gradient in the material creates a cyclic stress that can result in surface break-up by fatigue. The materials for cavity fabrication must therefore be selected in order to withstand such constraints whilst maintaining an acceptable surface state. The fatigue behaviour of Cu and CuZr alloy has been tested by inducing larger surface peak temperatures, thus reducing the number of cycles to failure, irradiating the surface with 50 ns pulses of UV light (308 nm) from an excimer laser. Surface break-up is observed after different number of laser shots as a function of the peak temperature. CuZr appears to withstand a much larger number of cycles than Cu, for equal peak temperature. The characterization of the surface states and possible means of extrapolating the measured behaviour to the expected number of pulses of CLIC are discussed in detail.  
 
MOPLT020 Limits to the Performance of the LHC with Ion Beams ion, luminosity, emittance, damping 578
 
  • J.M. Jowett, H.-H. Braun, M.I. Gresham, E. Mahner, A.N. Nicholson, E.N. Shaposhnikova
    CERN, Geneva
  • I.A. Pshenichnov
    RAS/INR, Moscow
  The performance of the LHC as a heavy-ion collider will be limited by a diverse range of phenomena that are often qualitatively different from those limiting the performance with protons. We summarise the latest understanding and results concerning the consequences of nuclear electromagnetic processes in lead ion collisions, the interactions of ions with the residual gas and the effects of lost ions on the beam environment and vacuum. Besides these limitations on beam intensity, lifetime and luminosity, performance will be governed by the evolution of the beam emittances under the influences of synchrotron radiation damping, intra-beam scattering, RF noise and multiple scattering on residual gas. These effects constrain beam parameters in the LHC ring throughout the operational cycle with lead ions.  
 
MOPLT030 Performance Limits and IR Design of a Possible LHC Luminosity Upgrade Based on Nb-Ti SC Magnet Technology quadrupole, luminosity, insertion, superconducting-magnet 608
 
  • F. Ruggiero, O.S. Brüning, R. Ostojic, L. Rossi, W. Scandale, T.M. Taylor
    CERN, Geneva
  • A. Devred
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  We investigate the maximum LHC performance for a possible IR design based on classical Nb-Ti insertion magnets. We then extend our analysis to a ternary Nb-based ductile alloy such as Nb-Ti-Ta, a less developed but relatively cheap super-conducting material which would allow us to gain about 1 T of peak field on the coils, and discuss the corresponding luminosity reach for a possible LHC upgrade compared to that based on Nb3Sn magnet technology.  
 
MOPLT031 LHC Abort Gap Filling by Proton Beam collimation, injection, proton, synchrotron 611
 
  • E.N. Shaposhnikova, S.D. Fartoukh, J.-B. Jeanneret
    CERN, Geneva
  Safe operation of the LHC beam dump relies on the possibility of firing the abort kicker at any moment during beam operation. One of the necessary conditions for this is that the number of particles in the abort gap should be below some critical level defined by quench limits. Various scenarios can lead to particles filling the abort gap. The relevant time scales associated with these scenarios are estimated for top energy where the synchrotron radiation losses are not negligible for uncaptured particle motion. Two cases are considered, both with RF on and RF off. The equilibrium distribution of lost particles in the abort gap defines the requirements for maximum tolerable relative loss rate and as a consequence the minimum acceptable longitudinal lifetime of the proton beam in collision.  
 
MOPLT045 Vacuum Induced Backgrounds in the New HERA Interaction Regions proton, background, vacuum, interaction-region 647
 
  • M. Seidel, M.G. Hoffmann
    DESY, Hamburg
  After the rebuild of the HERA interaction regions the experimental detectors were limited by beam induced backgrounds. Four types of background mechanisms were observed and identified - proton gas scattering, lepton gas scattering, synchrotron radiation and proton beam-halo losses. With some refined beam steering methods it was possible to tune the synchrotron radiation background to acceptable limits. The remaining most important effect was the scattering of the beam particles, mostly the protons, at the residual gas. In this contribution we describe our systematic attempts to investigate the complex behavior of the beam gas background and the measures taken to improve the situation. This includes dynamic pressure profile simulations and measurements, experimental determination of the background sensitivity profile along the beamline, the pressure development with current and time, and residual gas analysis. The background conditions were finally improved due to long term conditioning with beam, modifications of internal masks which were heated by higher order mode losses and moderate improvements of the pumping speed at strategic locations.  
 
MOPLT056 Feasibility Study for a Very High Luminosity Phi-factory luminosity, focusing, lattice, betatron 680
 
  • C. Biscari, D. Alesini, G. Benedetti, M.E. Biagini, R. Boni, M. Boscolo, A. Clozza, G.O. Delle Monache, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, A. Stecchi, A. Stella, C. Vaccarezza, M. Vescovi, M. Zobov
    INFN/LNF, Frascati (Roma)
  • E. Levichev, P.A. Piminov
    BINP SB RAS, Novosibirsk
  Particle factories are facing their future by looking at the possibility of upgrading the luminosity by orders of magnitude. The upgrade challenges are more stringent at lower energies. Double symmetric rings, enhanced radiation damping, negative momentum compaction and very short bunches at the collision point are the main features of a phi-factory feasibility study presented in this paper. The bunch length of few millimeters at the crossing point of the beams is obtained by applying the Strong RF Focusing principle which provides a modulation of the bunch length along the ring by means of a large momentum compaction factor together with a very high RF gradient. The collider design fits the existing DAFNE infrastructures with completely rebuilt rings and upgraded injection system.  
 
MOPLT086 Upgrading the Control System at KCSR monitoring, vacuum, power-supply, storage-ring 734
 
  • I.V. Krylov, V. Korchuganov, L.A. Moseiko, N.I. Moseiko, V.A. Novikov, A.G. Valentinov, Y.L. Yupinov
    RRC Kurchatov Institute, Moscow
  Till now Kurchatov Centre of Synchrotron Radiation facility control system is based on a CAMAC-oriented computers network. In this paper the project of upgrading and results of prototyping of the new equipment is submitted. Upgrading includes two levels. First, it is possible to create the modern CAMAC crate-controller, connected with standard network. More advanced variant will consist in replacement of CAMAC modules with the embedded controllers of equipment. Second level is a creation of a local managing network of personal computers, as consoles of the control system. The control system is functionally divided into four levels: 1) the controllers managing in a real-time mode by the executive equipment; 2) the workstations which are supporting the link with controllers by CAN-network; 3) the server of applications containing a dynamic database; 4) the PCs network for users applications. Examples of realisation of the software are presented.  
 
MOPLT102 To the Problem of Wake-field Excitation for Advanced Accelerator Concept electron, acceleration, plasma, laser 770
 
  • I.N. Onishchenko, V. Kiselev, A. Linnik, N. Onishchenko, G. Sotnikov
    NSC/KIPT, Kharkov
  • V. Ushkov
    RRC Kurchatov Institute, Moscow
  The advanced accelerator concept to use the wake-fields exited in dielectric by a sequence of electron bunches for high-gradient particle acceleration has been proposed and investigated in [*-***]. Two essential merits are being exploited. First of them [**] is the excitation by a regular sequence of electron bunches that allows superposing coherently the wake-fields excited by each bunch. The second one [***] concludes to multi-mode operation that leads to peaking of the resulting HF-field that is represented by a sequence of spikes of alternative signs with essentially higher amplitude comparatively to only principle mode excitation. The recent works performed in NSC/KIPT on theoretical studies, simulation, and experimental investigations of the wake-fields excitation by a train of 2 MeV electron bunches in a dielectric waveguide are presented. Transition and Cerenkov radiation excited by short bunches in a limited dielectric medium was theoretically investigated. The measurements of wake-fields output power and the electron energy spectrum were experimentally performed.

* W.Gai, P.Schoessow, B.Cole et al. Phys. Rev. Lett. 61, 2756 (1988) ** I.N.Onishchenko, V.A.Kiselev, G.V.Sotnikov et al. Proc. 1995 Particle Accelerator Conf., p. 782-3*** T.B.Zhang, J.L.Hirshfield, T.C.Marshall et al Proc. 1997 Particle Accelerator Conf., V.42, No.3, p.1341

 
 
MOPLT103 Radiation Resistant Magnetic Sensors for Accelerators permanent-magnet, monitoring, electron, background 773
 
  • I. Bolshakova, R. Holyaka
    LPNU, Lviv
  • S. Kulikov
    JINR, Dubna, Moscow Region
  • M. Kumada
    NIRS, Chiba-shi
  • C. Leroy
    Université de Montréal, Groupe de la Physique des Particules, Montréal, Québec
  The technology of obtaining the radiation resistant magnetic sensors, which characteristics remain stable under the irradiation with high dose of fast neutrons was designed. Radiation resistant sensors are developed on the base of InSb. While irradiation with neutron flux of 1010 n*cm-2*c-1 with energies 0.1…13?MeV, with the thermal neutrons part in the general flux of 20% and intermediate fluxes of 25%, the main sensors’ characteristics, that is their sensitivity to the magnetic field, change no more than for 0.05% up to the fluence of 1*1015 n*cm-2 and no more than for 1% up to the fluence of 3*1016 n*cm-2. Radiation resistant sensors are used for development of magnetic field monitoring system with measuring channels accuracy of 0,01%, which have a function of temperature measurement with the accuracy of 0.1?С at the place of sensor location, moreover, it has self diagnostics and self correction functions. This system passed the long-term testing of continuous 3 months operation at the Neutron Physics Laboratory, JINR, Dubna at the IBR-2 neutron reactor.  
 
MOPLT137 Beam Delivery Layout for the Next Linear Collider luminosity, emittance, linac, synchrotron 860
 
  • A. Seryi, Y. Nosochkov, M. Woodley
    SLAC, Menlo Park, California
  We present the latest design and layout of the NLC Beam Delivery System (BDS) for the first and second interaction region (IR). This includes the beam switchyard, skew correction and emittance diagnostics section, collimation system integrated with the final focus, the primary and post linac tune-up beam dumps, and arcs of the second interaction region beamline. The layout and optics are optimized to deliver the design luminosity in the entire energy range from 90GeV to 1.3TeV CM, with the first IR BDS also having the capabilities for multi-TeV extension.  
 
TUYBCH01 Design Criteria and Technology Challenges for the Undulators of the Future undulator, electron, synchrotron, vacuum 59
 
  • H. Kitamura, T. Hara, X. Maréchal, T. Tanaka
    RIKEN Spring-8 Harima, Hyogo
  • T. Bizen, T. Seike
    JASRI/SPring-8, Hyogo
  Nowadays, undulators are essential devices for synchrotron radiation (SR) facilities since they generate a quasi-monochromatic radiation with various features, high brightness , high energy and special polarization characteristics. Particularly, demands for high-energy radiation in the X-ray region have become much stronger in many research fields. Accordingly, a short-period undulator design has been developed, because they increase the number of periods in a unit undulator length and as a consequence, they generate brilliant synchrotron radiation. Also, short undulator periodicity enables emission of high-energy photons, and it opens the way for X-ray beamline operation in medium size synchrotron radiation facilities, such as SLS, NSLS, PLS, CLS, ALS, SOLEIL, DIAMOND, SPEAR-III and so on. From the same reason, a short-period undulator is very attractive for SASE-FEL or ERL facilities, since it lowers the electron beam energy necessary for X-ray operation. As a result this design makes a whole facility design compact and economic. In the talk, I will review the status of the development on short-period undulators of various types (in-vacuum, superconducting and cryogenic types) and describe the future direction.  
Video of talk
Transparencies
 
TUZACH01 Positron Source Options for Linear Colliders positron, target, photon, electron 69
 
  • K. Floettmann
    DESY, Hamburg
  Linear colliders require sources delivering particle intensities much higher than sources for storage rings and even several orders of magnitude larger than the SLC positron source, the highest intensity positron source operated so far. A fundamental limitation for the intensity of a positron source is set by the thermal stress in the target. Besides improvements of conventional positron sources, i.e. sources where an electron beam creates electron position pairs in an electromagnetic cascade, new concepts based on the direct conversion of gamma radiation offer possibilities for increased particle intensities. In these sources the hard gamma radiation has to be produced either in an undulator or by backscattering of laser light off an electron beam. An additional advantage of gamma radiation based sources is the possibility to produce polarized positrons. The talk will give an overview of the developments of high intensity unpolarized and polarized positron sources for linear colliders.  
Video of talk
Transparencies
 
TUPKF008 Status of the HoBiCaT Superconducting Cavity Test Facility at BESSY linac, vacuum, superconductivity, power-supply 970
 
  • J. Knobloch, W. Anders, J. Borninkhof, S. Jung, M. Martin, A. Neumann, D. Pflückhahn, M. Schuster
    BESSY GmbH, Berlin
  BESSY has recently constructed the HoBiCaT cryogenic test facility for superconducting TESLA cavity units, including all ancillary devices (helium tank, input coupler, tuner, magnetic shielding). It is designed to house two such units in a configuration similar to that envisaged for the superconducting CW linac of the BESSY FEL. These units are presently being fabricated, prepared and assembled by industry. HoBiCaT will be used to address many of the issues that must be considered prior to finalizing the design of the proposed linac. Rapid turn-around-tests permit the investigation of items such as RF regulation, microphonic detuning and cryogenic parameters/achievable pressure stability. These test will also serve as the first step towards qualifying the industrial production of assembled cavity units. The commissioning of HoBiCaT is scheduled for Spring 2004 and the current status is presented here.  
 
TUPKF033 Cryogenic Performance of the Prototype Cryomodule for ADS Superconducting LINAC linac, alignment, synchrotron, proton 1033
 
  • N. Ohuchi, E. Kako, S. Noguchi, T. Shishido, K. Tsuchiya
    KEK, Ibaraki
  • N. Akaoka, H. Kobayashi, N. Ouchi, T. Ueno
    JAERI/LINAC, Ibaraki-ken
  • T. Fukano
    Nippon Sanso Corporation, Tokyo
  • H. Hara, M. Matsuoka, K. Sennyu
    MHI, Kobe
  A prottype cryomodule containing two 9-cell superconducting cavities of b=0.725 and f=972MHz is being constructed under the collaboration of Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK) on the development of superconducting LINAC for Accelerator Driven System (ADS). Cryogenic performances of the cryomodule and 2K He-system will be reported.  
 
TUPKF035 RF System for Compact Medical Proton Synchrotron synchrotron, proton, acceleration, impedance 1039
 
  • Z. Fang, K. Egawa, K. Endo, S. Yamanaka
    KEK, Ibaraki
  • Y. Cho, T. Fusato, T. Hirashima
    DKK, Kanagawa
  The rf system has been developed for the compact medical proton synchrotron. The rf system will be operated in pulse mode with the fundamental rf frequency sweeping from 1.6 to 15 MHz during the acceleration time of 5 ms. The required rf cavity voltage is a function of acceleration time too, with the voltage of fundamental varying from 13 to 6 kV. Besides, high order harmonics are also considered to apply to the rf system, and the cavity peak voltage varying from 20 to 9 kV during the acceleration time is expected. The performance of the rf system is being studied and will be presented.  
 
TUPKF041 Quasi-optic RF Power Transmission Line from a FEM Oscillator to the Model of the CLIC Accelerating Structure vacuum, diagnostics, insertion, alignment 1054
 
  • A. Kaminsky, A.V. Elzhov, E.A. Perelstein, N.V. Pilyar, T.V. Rukoyatkina, S. Sedykh, A.P. Sergeev, A. Sidorov
    JINR, Dubna, Moscow Region
  • N.S. Ginzburg, S.V. Kuzikov, N.Yu. Peskov, M.I. Petelin, A. Sergeev, N.I. Zaitsev
    IAP/RAS, Nizhny Novgorod
  Experimental investigation of a copper resonator lifetime under multiple action of 30 GHz power pulses is now carried out by the collaboration of CLIC team (CERN), FEM group of JINR (Dubna) and IAP RAS (Nizhny Novgorod). A quasi-optic two-mirror transmission line is used between the FEM oscillator and test cavity. An oversized FEM output waveguide based on the wavebeam transformation (Talbot effect) provides the optimal transverse distribution of the radiation, eliminates the output window breakdown and decrease the influence of the reflected wave on the FEM oscillator regime.  
 
TUPKF053 New Waveguide-type HOM Damper for the ALS Storage Ring RF Cavities storage-ring, damping, vacuum, synchrotron 1069
 
  • S. Kwiatkowski, K.M. Baptiste, J. Julian
    LBNL/ALS, Berkeley, California
  The ALS storage ring 500 MHz RF system uses two re-entrant accelerating cavities powered by a single 320kW PHILLIPS YK1305 klystron. During several years of initial operation, the RF cavities were not equipped with effective passive HOM damper systems. Longitudinal beam stability was achieved through cavity temperature control and the longitudinal feedback system (LFB), which was often operating at the edge of its capabilities. As a result, longitudinal beam stability was a significant operations issue at the ALS. During two consecutive shutdown periods (April 2002 and 2003) we installed E-type HOM dampers on the main and third harmonic cavities. These devices dramatically decreased the Q-values of the longitudinal anti-symmetric HOM modes. The next step is to damp the rest of the longitudinal HOM modes in the main cavities below the synchrotron radiation damping level. This will hopefully eliminate the need for the LFB and set the stage for a possible increase in beam current. The ?waveguide? type of HOM damper was the only option that didn?t significantly compromise the vacuum performance of the RF cavity. The design process and the results of the low level measurements of the new waveguide dampers are presented in this paper.  
 
TUPKF061 The SPEAR3 RF System klystron, damping, feedback, impedance 1084
 
  • P.A. McIntosh, S. Allison, P. Bellomo, S. Hill, V. Pacak, S. Park, J.J. Sebek, D.W. Sprehn
    SLAC, Menlo Park, California
  SPEAR2 was upgraded in 2003, to a new 3rd Generation Light Source (3GLS) enabling users to take better advantage of almost 100x higher brightness and flux density over its predecessor SPEAR2. As part of the upgrade, the SPEAR2 RF system has been re-vamped from its original configuration of one 200 kW klystron feeding a single 358.5 MHz, 5-cell aluminum cavity; to a 1.2 MW klystron feeding four 476.3 MHz, HOM damped copper cavities. The system installation was completed in late November 2003 and the required accelerating voltage of 3.2 MV (800 kV/cavity) was very rapidly achieved soon after. This paper details the SPEAR3 RF system configuration and its new operating requirements, highlighting its installation and subsequent successful operation.  
 
TUPLT069 Approaching to a Mono-modal Accelerating Cavity based on Photonic Band-gap Concepts simulation, coupling, lattice, scattering 1309
 
  • M.R. Masullo
    INFN-Napoli, Napoli
  • A. Andreone, E. Di Gennaro, G. Lamura
    Naples University Federico II, Napoli
  • F. Francomacaro, M. Panniello, V.G. Vaccaro
    Naples University Federico II and INFN, Napoli
  • G. Keppel, V. Palmieri, D. Tonini
    INFN/LNL, Legnaro, Padova
  One of the main problem of high intensity accelerators is the presence of high order modes (HOMs) which might degrade the beam quality. Accelerating cavities require HOMs suppression while keeping high quality factor (Q) fundamental mode. Both these requirements can be hardly met in closed metallic cavities. In low frequency cases and for particular geometries it is possible to partially suppress HOMs, but at high frequencies and for superconducting cavities configuration becomes cumbersome and technically unviable. We propose here a high Q cavity based on Photonic Band Gap (PBG) concepts, operating in the microwave region. The cavity consists of a two-dimensional lattice, where posts (dielectric, metallic or superconducting) are sandwiched by two conducting plates. This sandwich exhibits two kinds of frequency bands: 'pass-bands' and 'stop-bands'. It is possible to localize modes in an equivalent cavity obtained by removing posts. These modes are localized in the 'cavity'. In this way, one can obtain a quasi-mono-modal cavity: high Q fundamental mode and HOMs falling into the pass bands. We will present the study, the optimisation and the measurements of our metallic (Copper) PBG structure working in the 2-20 GHz range. The development of a different cryogenic set-up, necessary to characterise an all superconducting or an hybrid (dielectric/metallic) structure, is under way.  
 
TUPLT071 A 5 MeV Electron Linac for Radiation Processing electron, cathode, linac, focusing 1315
 
  • A. Trifirò, L. Auditore, R.C. Barnà, D. De Pasquale, A. Italiano, M. Trimarchi
    INFN - Gruppo Messina, S. Agata, Messina
  In recent years, radiation processing is rapidly growing in various field of industrial treatments and scientific research as a safe, reliable and economic technique. To match the requirements of several applications, a 5 MeV, 1 kW electron linac has been developed at the Dipartimento di Fisica (Università di Messina), in collaboration with the ENEA Accelerators Group (Frascati- Rome). This self- containing standing wave accelerator, driven by a 3 GHz, 2.5 MW Magnetron, has been designed, by means of the SUPERFISH and PARMELA codes, in such a way as to obtain an autofocusing structure, that will be used to develop a transportable system for 'in-situ' industrial radiography and X-ray digital tomography. For this accelerator, compact pulse forming circuits have been properly developed for the magnetron and the cathode, and pulse frequency can be varied ranging from 1 to 300 Hz, thus allowing the study of several applications of radiation processing. Main features of the accelerating structure, as well as beam spot dimensions, surface dose distribution and electron beam energy range will be described.  
 
TUPLT105 Measurement of Activation Induced by an Argon Beam in a Copper Target at the SIS18 target, ion, radioactivity, heavy-ion 1399
 
  • A. Fertman, A. Golubev, M. Prokuronov, B.Y. Sharkov
    ITEP, Moscow
  • G. Fehrenbacher, R.W. Hasse, I. Hofmann, E. Mustafin, D. Schardt, K. Weyrich
    GSI, Darmstadt
  Results of the measurement of activation induced by Argon beam with energies of E=100,200,800 MeV/u in the copper target are presented. The densities of various radioactive isotopes are derived from the measurements. Long-time prediction of radioactivity and accumulated doses in the accelerator equipment is calculated.  
 
TUPLT117 Test of Materials for the High Temperature Intense Neutron Target Converter target, electron, vacuum, diagnostics 1413
 
  • K. Gubin, M. Avilov, S. Fadeev, A. Korchagin, A. Lavrukhin, P.V. Logatchev, P. Martyshkin, S.N. Morozov, S. Shiyankov
    BINP SB RAS, Novosibirsk
  • J. Esposito, L.B. Tecchio
    INFN/LNL, Legnaro, Padova
  Nowadays in LNL INFN (Italy) the project for gain and study of short-lived radioactive isotopes is in progress [1]. The intense neutron target is required for these goals. In BINP, Russia, the design of high temperature target cooled by radiation is proposed. Presented paper describes the results of preliminary test of materials for the target converter: MPG6-brand graphite, graphite material on the basis of 13C, boron carbide, glassy carbon. Test included the distributed heating over volume of samples with the electron beam up to conditions, simulating the converter working regime (heating power density up to 1300 W/cm2, temperature up to 20000C, temperature gradient up to 1000C/mm). Graphite materials show its adaptability under conditions specified.  
 
TUPLT118 Test of Construction for High Temperature Intense Neutron Target Prototype target, simulation, electron, vacuum 1416
 
  • K. Gubin, M. Avilov, D. Bolkhovityanov, S. Fadeev, A. Lavrukhin, P.V. Logatchev, P. Martyshkin, A.A. Starostenko
    BINP SB RAS, Novosibirsk
  • O. Alyakrinsky, L.B. Tecchio
    INFN/LNL, Legnaro, Padova
  Within the framework of the creation of the high temperature intense neutron target prototype, the thermal tests of the preliminary design were done in BINP. Tests were aimed at experimental definition of temperature and heat flux distribution over the construction, heat transfer via the contact areas between materials selected, specifying the properties of these materials. This paper presents the experimental test results as well as the comparison of experimental data with the results of numerical simulation of the working regimes of the construction.  
 
TUPLT129 NESTOR Reference Orbit Correction electron, pick-up, laser, storage-ring 1431
 
  • V.A. Ivashchenko, P. Gladkikh, I.M. Karnaukhov, A. Mytsykov, V.I. Trotsenko, A.Y. Zelinsky
    NSC/KIPT, Kharkov
  It is known that intensity of scattered radiation in X-rays generators based on Compton scattering strongly depends on relative position of electron and laser beams. For this reason it is very important to have effective system of reference orbit correction and beam position control as well along whole ring as at the interaction point. In the paper the results of design and development of reference orbit correction system for compact storage ring NESTOR are presented. The total reference orbit correction will be carried out in vertical plane only. Correctors will be disposed on quadrupole lenses and will be provide reference orbit correction angle up to 0.10. The local correction at the interaction point will be provided with four correctors located at the interaction straight section. In the article results of calculations, layout of whole system, quadrupole lenses and pick-up station parameters and schemes are presented.  
 
TUPLT180 Results of the NASA Space Radiation Laboratory Beam Studies Program at BNL ion, booster, quadrupole, power-supply 1547
 
  • K.A. Brown, L. Ahrens, R.H. Beuttenmuller, I.-H. Chiang, D.C. Elliott, D. Gassner, Z. Li, I. Marneris, J. Mead, J. Morris, D. Phillips, V. Radeka, A. Rusek, N. Tsoupas, B. Yu, K. Zeno
    BNL, Upton, Long Island, New York
  The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The NSRL makes use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. The purpose of the NSRL beam studies program is to develop a clear understanding of the beams delivered to the facility, to fully characterize those beams, and to develop new capabilities in the interest of understanding the radiation environment in space. In this report we will describe the first results from this program.  
 
TUPLT181 Results of the First Run of the NASA Space Radiation Laboratory at BNL ion, booster, extraction, heavy-ion 1550
 
  • K.A. Brown, L. Ahrens, J.M. Brennan, J. DeLong, C. Gardner, D. Gassner, J. Glenn, Y. Kotlyar, I. Marneris, A. Rusek, N. Tsoupas, K. Zeno
    BNL, Upton, Long Island, New York
  The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The results of commissioning of this new facility were reported in [*]. In this report we will describe the results of the first run. The NSRL makes use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. Many modes of operation were explored during the first run, demonstrating all the capabilities designed into the system. Heavy ion intensities from 100 particles per pulse up to $2×109$ particles per pulse were delivered to a large variety of experiments, providing a dose range up to 70 G/min over a 5x5 $cm2$ area. Results presented will include those related to the production of beams that are highly uniform in both the transverse and longitudinal planes of motion [**].

* K.A.Brown, et al, ‘‘Commissioning Results of Slow Extraction of Heavy Ions from the AGS Booster‘‘, Proceedings of the 2003 Particle Accelerator Conference, Portland, OR, 2003** N.Tsoupas, et al, ‘‘Commissioning of the Beam Transfer Line of the Booster Application Facility (BAF) at BNL'', These Proceedings

 
 
WEYCH02 Technical Issues for Large Accelerators based on High Gradient SC Cavities electron, collider, vacuum, linac 137
 
  • C. Pagani, C. Pagani
    DESY, Hamburg
  The perspective to build large accelerators based on high gradient superconducting cavities is posing a number of new problems that have been addressed in the preparation of the TESLA project. Starting from the experience gained with the past large installations, such as LEP2 at CERN and CEBAF at JLab, in this paper I discuss the new demands and the solution envisaged. Industrial production issues are focussed in terms of large scale production, reviewed quality control criteria and cost reduction. The impact on component design and engineering together with the expected improvements in term of performances and reliability are also outlined.  
Video of talk
Transparencies
 
WEOBCH01 Performance Requirements for Monitoring Pulsed, Mixed Radiation Fields around High-energy Acclerators monitoring, target, simulation, hadron 147
 
  • D. Forkel-Wirth, S.M. Mayer, H.G. Menzel, A. Muller, T. Otto, M. Pangallo, D. Perrin, M. Rettig, S. Roesler, L. Scibile, H. Vincke
    CERN, Geneva
  • C. Theis
    TUG/ITP, Graz
  Radiation protection survey around CERN's High Energy Accelerators represents a major technical and physical challenge due to the pulsed and complexity of the mixed radiation fields. The fields are composed of hadrons, leptons and photons ranging in energy from fractions of eV to several 10 GeV. In preparation of the implementation of a Radiation Monitoring System for the Environment and Safety (RAMSES) of the future Large Hadron Collider (LHC) and its injectors comprehensive studies were performed to evaluate the suitability of different existing monitors for this task. Different ionization chambers were exposed to short, high-intensity radiation pulses and their saturation levels for high dose rates determined. Limiting factors such as recombination effects and the capacity of the electronics to process a high number of charges within very short time were studied in detail. These results are being used to optimize the design of the read-out electronics. In additional studies, the response of two different types of ionization chambers to high-energy radiation was investigated by measurements in the mixed radiation fields of the CERN EU high-energy Reference Field (CERF) facility. The results of the experiments agreed well with calculations, clearly demonstrating that modern Monte-Carlo simulation techniques can be used to design radiation monitors and to optimize their performance.  
Video of talk
Transparencies
 
WEILH01 Methods for Successful Technology Transfer in Physics electron, instrumentation, collider, plasma 198
 
  • K.N. Hill
    Qi3, Cambridge
  The development of accelerators for scientific research generates significant technologies of interest to industry. As physicists and technologists we also require strong partnerships with industry in order that it may supply us with the instrumentation and systems we require for new apparatus. We will discuss the methods developed for the UK Particle Physics and Astronomy Research Council (PPARC) and applied on behalf of CERN to encourage successful knowledge transfer into industry. Case studies will illustrate the hurdles that must be surmounted and effective methods to build successful partnerships, licensing opportunities and spinout companies. Factors considered will include assessment of the commercial potential of technologies, personal motivations for academic/industrial collaboration, sources of funding, and effects on the academic groups involved in knowledge transfer activity.  
Video of talk
Transparencies
 
WEPKF001 Diffusion Welding of Heterogeneous Materials in Accelerator Technique vacuum, induction, lattice 1586
 
  • V.S. Avagyan
    CANDLE, Yerevan
  • A. Babayan, N.M. Dobrovolski, I.V. Tunyan
    YerPhI, Yerevan
  The results of the joining of heterogeneous materials, such as titanium with stainless steel (serviceable at 4.2 K), copper with aluminum, titanium with niobium (this work has been carried out for TESLA project), stainless steel with aluminum, copper with stainless steel are presented in this work.  
 
WEPKF017 The 5 T Superconducting Undulator for the LHC Synchrotron Radiation Profile Monitor undulator, synchrotron, synchrotron-radiation, proton 1630
 
  • R. Maccaferri, M. Facchini, R. Jung, D. Tommasini, W.  Venturini Delsolaro
    CERN, Geneva
  A Synchrotron Radiation Profile Monitor will be used in the LHC to measure the beam profiles from the injection energy of 450 GeV to the nominal energy of 7 TeV. The radiation will be provided by a sequence of two separate magnets: a two-periods 5 T superconducting undulator and the beam separation dipole D3. After a short description of the profile monitor layout, the paper reviews the electromagnetic and mechanical design of the undulator, and reports on the fabrication and cold test results of a first half period prototype.Finally, for the LHC operation with lead ion beams,a proposal for a monitor sensitivity upgrade by using a 12 T. superconducting undulator is presented and discussed.  
 
WEPKF038 The Alignment Jacks of the LHC Cryomagnets alignment, vacuum, quadrupole, collider 1687
 
  • J. Dwivedi, S.G. Goswami, A. Kumar, V. Madhumurthy, H.C. Soni
    CAT, Indore (M.P.)
  • V. Parma
    CERN, Geneva
  The precise alignment of the some 1700 cryomagnets of the LHC collider, requires the use of some 7000 jacks. The specific requirements and the need for an cost-effective solution for this large production, justified the development and industrialisation of a dedicated mechanical jack which was developed, and is now being produced, in the framework of a collaboration between CERN and the Center for Advanced Technology in India. Three jacks support each of the 32-ton heavy, 15-meter long cryo-dipoles of LHC, and provide the required alignment features. The main requirements are a setting resolution of 0.05 mm, and a range of movement of 20 mm in the horizontal and 40 mm in the vertical direction. Each jack has two degrees of controlled movement in the horizontal and vertical direction, whereas the remaining horizontal movement is left free. By a suitable choice of the layout of the three jacks, the full range of alignment of a cryo-magnet can be obtained. The design of the jacks evolved from a preliminary value analysis between various concepts, towards the complete engineering of the retained concept, selection of the most appropriate and cost-effective industrial production processes and setting-up of an effective quality assurance policy. Building and testing of 36 prototype jacks allowed an extensive experimental validation of their performance at CERN, where they were operated in the String 2 facility, and yielded an improved understanding for cost-effective steering of the production processes before launching the series production. Presently, the mass production of the jacks is in progress with two Indian manufacturers, and some 1500 jacks have already been delivered to CERN. Considering the successful performance of the jacks, it is now envisaged to extend the use of the same type of jacks to provide the even higher-demanding alignment of the low-beta quadrupoles of LHC.  
 
WEPKF039 The Vacuum System of Super SOR vacuum, synchrotron, synchrotron-radiation, insertion 1690
 
  • H. Sakai, M. Fujisawa, A. Kakizaki, T. Kinishita, H. Kudo, N. Nakamura, O. Okuda, S. Shibuya, K. Shinoe, H. Takaki
    ISSP/SRL, Chiba
  • K. Kobayashi
    KEK, Ibaraki
  • T. Koseki
    RIKEN/RARF/BPEL, Saitama
  • H. Ohkuma
    JASRI/SPring-8, Hyogo
  • S. Suzuki
    LNS, Sendai
  The Super-SOR light source is a Japanese VUV and soft X-ray third-generation synchrotron radiation source, which consists of 1.8GeV storage ring and injector. The beam current is circulated up to 400mA. These accelerators are designed so as to fully meet requirements for top-up injection. In order to realize these operation modes, our vacuum system are required on following conditions. One is to obtain the long lifetime. The other is not to melt the vacuum chamber by irradiating the high flux synchrotron radiation. Finally beam instability is not occurred by large wake fields. We describe the design of the vaccum chamber of Super-SOR and present the recent R&D concerning this system.  
 
WEPKF041 Permanent Magnet Generating High and Variable Septum Magnetic Field and its Deterioration by Radiation permanent-magnet, septum, booster, beam-losses 1696
 
  • T. Kawakubo, E. Nakamura, M. Numajiri
    KEK, Ibaraki
  • M. Aoki, T. Hisamura, E. Sugiyama
    NEOMAX Co., Ltd., Mishima-gun, Osaka
  Conventional high field septum magnet is fed by DC current or pulse current. In the case of DC, the problem of coil support is not very important, but the cooling of the coil is serious problem. While, in the case of pulse, the problem of support is much important than that of cooling. However, if the septum magnet is made of permanent magnet, those problems are dissolved. And the cost for electricity and cooling water can be exceedingly decreased. Therefore, we made the model septum magnet which has 1/4 scale of the real size and generates 1[T] with the variable range of ± 10%. The magnetic field distribution in the gap by changing the representative field is reported. When this permanent magnet is set in an accelerator, the deterioration of the permanent magnet by radiation will be serious problem. We also report the dependence of the magnetic fields generated by permanent magnet samples on accumulated radiation by various types of radiation source.  
 
WEPKF054 Auto-filling Cryogenic System for Superconducting Wiggler wiggler, synchrotron, synchrotron-radiation, superconducting-RF 1726
 
  • F.-Y. Lin, C.-H. Chang, H.-H. Chen, T.-C. Fan, M.-H. Huang, C.-S. Hwang
    NSRRC, Hsinchu
  A 3.2 Tesla superconducting wiggler with period length of 6.0 cm (SW6) was installed in January of 2004 at the National Synchrotron Radiation Research Center (NSRRC). A cryogenic plant for superconducting rf cavity will also provide liquid helium and liquid nitrogen for SW6 by using an independent automatic filling system. To facilitate a stable and precise auto-filling process, a PID controller, the kernel of the auto-filling system, will control the valves of liquid helium and liquid nitrogen, respectively. The authors shall present the control algorithm of different operation modes, namely the pre-cooling mode and normal auto-filling mode. The boil off rate of liquid helium and liquid nitrogen will be discussed.  
 
WEPKF055 Design and Implementation of a Switching Mode Bipolar Power Stage of the Correction Power Supply power-supply, feedback, synchrotron, synchrotron-radiation 1729
 
  • C.-Y. Liu, C.H. Kuo, K.-B. Liu
    NSRRC, Hsinchu
  In order to enhance efficiency of the correction power supply, the switching mode bipolar power stage was to implement and to substitute for the original power stage of the correction power supply. To ensure higher efficiency, the programming dc bus voltage of the power stage of the correction power supply must be working in accordance with the output current state and load. A new power conversion stage was constructed and employs power MOSFET operating at higher switching frequency then old 60 Hz energy conversion mode system. This will not only improve the efficiency but also decrease the weight of the correction power supply. The new switching mode power stage supply a bipolar power dc bus power and automatic turning working voltage by the feedback balance circuit. Results and working performance will be presented in this paper.  
 
WEPKF070 Design Issues for the Superconducting Magnet that goes around the Liquid Hydrogen Absorber for the Muon Ionization Cooling Experiment (MICE) vacuum, focusing, magnet-design, superconducting-magnet 1765
 
  • M.A. Green, G. Barr, J. Cobb, W. Lau, R.S. Senanayake, H. Witte, S.Q. Yang
    OXFORDphysics, Oxford, Oxon
  • E. Baynham, T.W. Bradshaw, P. Drumm, Y. Ivanyushenkov, J. Rochford
    CCLRC/RAL, Chilton, Didcot, Oxon
  This report describes the design issues that are associated with a superconducting focusing solenoid that goes around a liquid hydrogen absorber for the Muon Ionization Cooling Experiment (MICE) proposed for the Rutherford Appleton Laboratory. The solenoid consists of two superconducting coils that may operated at the same polarity or at opposite polarities. As a result, the coils and their support structure must be designed to carry a 300 ton inter-coil force that is forcing the coils apart along their axis. The basic design parameters for the focusing magnet are discussed. The magnet and its cryostat are designed so that the absorber can be assembled and tested before installation into the pre-tested focusing solenoid. A safety requirements for MICE dictate that the insulating vacuum for the superconducting magnet be separated from the insulating vacuum for the absorber and that both vacuum be separated from the experiment vacuum and the vacuum within adjacent RF cavities. The safety issues associated with the arrangement of the various vacuums in the MICE focusing modules are presented. The effect of magnet operation and magnet quench on the liquid hydrogen absorber is also discussed.  
 
WEPKF082 Radiation Damage Studies with Hadrons on Materials and Electronics permanent-magnet, multipole, radioactivity, hadron 1795
 
  • J.E. Spencer, J. Allan, S. Anderson, R. Wolf
    SLAC, Menlo Park, California
  • M. Boussoufi
    UCD/MNRC, McClellan, California
  • D.E. Pellet
    UCD, Davis
  • J.T. Volk
    Fermilab, Batavia, Illinois
  Many materials and electronic devices need to be tested for the radiation environment expected at the proposed linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, electrons and gammas during the life of the facility. Examples are NdFeB permanent magnets which are being considered for the damping rings and final focus, electronic and electro-optical devices which will be utilized in the detector readout and accelerator control systems and CCDs required for the vertex detector. The effects of gammas on a broad range of materials was presented at NSREC2002 and our understanding of the current situation concerning rare earth permanent magnets at PAC2003 where a program was proposed using neutrons from the McClellan Nuclear Reactor Center (MNRC) that has a number of areas for irradiating samples with neutron fluxes up to 4.5·1013 n/cm2s. A specialized area allows irradiation with 1 MeV-equivalent neutrons with fluxes of 4.2·1010 n/cm2s while suppressing thermal neutrons and gammas by large factors. We give our latest results and their interpretation using this facility.  
 
WEPKF083 SPEAR3 INTERMEDIATE DC MAGNET POWER SUPPLIES power-supply, quadrupole, synchrotron, synchrotron-radiation 1798
 
  • A.C. de Lira, P. Bellomo
    SLAC, Menlo Park, California
  The Stanford Synchrotron Radiation Laboratory (SSRL) has successfully commissioned SPEAR3, its newly upgraded 3-GeV synchrotron light source. First stored beam occurred December 15, 2003 and 100mA operation was reached on January 20, 2004. This paper describes the specification, design, and performance of the SPEAR3 intermediate DC magnet power supplies (IPS) that consist of tightly-regulated (better than 10 ppm) current sources ranging from 60 A to 500 A and output powers ranging from a few kW to 22.5kW. A total of 69 IPS are in successful operation. The SPEAR 3 upgrade performance and reliability requirements mandated new power supplies for both the SPEAR3 storage ring, and for the booster-to-SPEAR3 transport line. IPS are widely used at SPEAR3 to power single quadrupoles, dipoles, families of quadrupoles and sextupoles, and also on the Titanium sublimation pumps. IPS' topology allows them to be series operated for those magnet strings requiring higher voltages. A compact 19" standard rack-mounted design is common to all the units. These are off-line, switch-mode, operating at 16 kHz to reduce space and provide for fast output response and high efficiency.  
 
WEPLT002 Shielding Design Study for CANDLE Facility shielding, beam-losses, electron, storage-ring 1816
 
  • K.N. Sanosyan, M. Aghasyan, R.H. Mikaelyan
    CANDLE, Yerevan
  • V.M. Vartanian
    Stanford University, Stanford, Califormia
  The radiation shielding design study for the third generation synchrotron light source CANDLE is carried out. The electron beam loss estimates have done for all the stages from linac to storage ring. A well-known macroscopic model describing the dose rate for point losses has been used to calculate the shielding design requirements of the facility.  
 
WEPLT024 Scheduling the Installation of the LHC Injection Lines injection, dipole, quadrupole, vacuum 1879
 
  • L. Lari, H. Gaillard, V. Mertens
    CERN, Geneva
  The installation of the two LHC injection lines has to fit within tight milestones of the LHC project and of CERN?s accelerator activity in general. For instance, the transfer line from the SPS to LHC point 8 (to fill the anti-clockwise LHC ring) should be tested with beam before the end of 2004 since the SPS will not run in 2005. It will first serve during the LHC sector test in 2006. Time constraints are also very strong on the installation of the transfer line from the SPS to LHC point 2 (for the clockwise LHC ring): its tunnel is the sole access for the LHC cryo-magnets and a large part of the beam line can only be installed once practically all LHC cryo-magnets are in place. Of course, the line must be operational when the LHC starts. This paper presents the various constraints and how they are taken into account for the logistics and installation planning of the LHC injection lines.  
 
WEPLT027 Connection Cryostats for LHC Dispersion Suppressors alignment, dipole, vacuum, shielding 1888
 
  • S. Marque, T. Colombet, M. Genet, B. Skoczen
    CERN, Geneva
  The lattice of the Large Hadron Collider (LHC) being built at CERN is based on 8 standard arcs of 2.8 km length. Each arc is bounded on either side by Dispersion Suppressors connected to the arc by connection cryostats providing 15m long drift spaces. As for a dipole magnet, the connection cryostat provides a continuity of beam and insulation vacuum, electrical powering, cryogenic circuits, thermal and radiation shielding. In total 16 modules will be constructed. The stringent functional specification has led to various analyses. Among them, a light mechanical structure has been developed to obtain a stiffness comparable to a dipole magnet, for alignment purpose. Thermal studies, included λ front propagation, have been performed to ensure a cooling time down to 1.9K within the time budget. A special cooling scheme around the beam tubes has been chosen to cope with heat loads produced during operation. We will report on the general design of the module and on the manufacturing process adopted to guarantee the tight alignment of the beam tubes once the module installed in the machine. Special emphasis will be given on thermo-mechanical analysis, λ front propagation and on beam-tubes cooling scheme.  
 
WEPLT033 The LHC Radiation Monitoring System for the Environment and Safety monitoring, radioactivity, instrumentation, photon 1903
 
  • L. Scibile, D. Forkel-Wirth, H.G. Menzel, D. Perrin, G. Segura Millan, P. Vojtyla
    CERN, Geneva
  A state of the art radiation monitoring and alarm system is being implemented at CERN for the LHC. The RAdiation Monitoring System for the Environment and Safety (RAMSES) comprises about 350 monitors and provides ambient dose equivalent rates measured in the LHC underground areas as well as on the surface inside and outside the CERN perimeter. In addition, it monitors air and water released from the LHC installations. Although originally conceived for radiation protection only, RAMSES also integrates some conventional environmental measurements such as physical and chemical parameters of released water and levels of non-ionizing radiation in the environment. RAMSES generates local radiation warnings, local alarms as well as remote alarms on other monitored variables, which are transmitted to control rooms. It generates operational interlocks, allows remote supervision of all measured variables as well as data logging and safe, long-term archiving for off-line data analysis and reporting. Requirements of recent national and international regulations in combination with CERN's specific technical needs were translated into the RAMSES specifications. This paper outlines the scope, the organization, the main system performance and the system design.  
 
WEPLT051 Sub-Picosecond Electron Bunches in the BESSY Storage Ring electron, synchrotron, optics, storage-ring 1954
 
  • G. Wustefeld, J. Feikes, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  BESSY is a low emittance, 1.7 Gev electron storage ring. A dedicated, low alpha optics is applied to produce short electron bunches for coherent synchrotron radiation (CSR) in the THz range[*]. By a further detuning of the optics, stable pulses as short as 0.7 ps rms length were produced. The sub-ps pulse shape is analysed by an auto-correlation method of the emitted CSR. The CSR-bursting instability is measured and compared with theory to estimate the current for stable, sub-ps pulses. Present limits of the low alpha optics are discussed.

* M. Abo-Bakr et al., Phys. Rev. Lett. 88, 254801 (2002).

 
 
WEPLT063 Investigation of Cavity Induced Longitudinal Coupled Bunch Mode Instability Behaviour and Mechanisms damping, synchrotron, storage-ring, simulation 1990
 
  • R.G. Heine, P. Hartmann, H. Huck, G. Schmidt, T. Weis
    DELTA, Dortmund
  The narrowband impedances of RF-resonators in a circular accelerator can drive coupled bunch mode - CBI - instabilities which might spoil the overall beam quality. Often, as in synchrotron radiation light sources e.g. the instability does not lead to beam loss but to a severe degradation of the source brilliance. Investigations of longitudinal CBIs have been performed at the DELTA storage ring with a single DORIS-type cavity for future comparision with the behaviour of a HOM-damped cavity to be tested at DELTA. This resonator is presently developed and built within an EU-collaboration. The beam was deliberately driven into instability using the beam current as well as the cavity temperature as individual parameters. The instability characterisations at low (542 MeV) and high (1,5 GeV) energy exhibit a complex behaviour. The strength of the instability measured by the bunch excursions in the case of longitudinal CBIs, but also the spreading of the instability across neighbouring modes depends on parameters such as beam energy, resonant impedance but also on counteracting mechanisms like synchrotron radiation and Landau damping. The paper will cover the experimental results together with estimations of the influence and mechanism of Landau damping.  
 
WEPLT092 Equilibrium Longitudinal Distribution for Localized Regularized Inductive Wake synchrotron, damping, radio-frequency, vacuum 2065
 
  • S. Petracca, T. Demma
    U. Sannio, Benevento
  • K. Hirata
    GUAS, Kanagawa
  In a recent paper [*] we have shown that a localized wake assumption and the Gaussian approximation for the longitudinal beam distribution function can be used to understand the nature of the stationary solutions for the inductive wake, by comparison between the resulting map and the Haissinski equation, which rules the (less realistic) case of a uniformly distributed wake. In particular we showed the non-existence of solutions of Haissinski's equation when the inductive wake strength exceeds a certain threshold [**] to correspond to the onset of chaos in the map evolving the moments of the beam distribution from turn to turn. In this paper we use the same formalism to confirm that as noted in [**] for Haissinski's equation, a steady state solution for the longitudinal phase space distribution function always exists if a physically regularized inductive wake, which satisfies an obvious causality condition, is used.

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

 
 
WEPLT103 Radiation Damage in Magnets for Undulators at Low Temperature electron, undulator, permanent-magnet, linac 2092
 
  • T. Bizen, X. Maréchal, T. Seike
    JASRI/SPring-8, Hyogo
  • Y. Asano
    JAERI/SPring-8, Hyogo
  • T. Hara, H. Kitamura, T. Tanaka
    RIKEN Spring-8 Harima, Hyogo
  • D.E. Kim, H.S. Lee
    PAL, Pohang
  Nd2Fe14B permanent magnets are used in many insertion devices for its good magnetic and mechanical properties. However, the radiation sensitivity of the magnets would be concern when they are used in a strong radiation environment. It is known that these magnets with very high coercivity show high resistance to radiation, though the substance for increasing the coercivity decrease the remanence. The coercivity and remanence of this magnet exhibit negative dependence against temperature, so it is expected to these magnets to show high remanence and high resistance to radiation at low temperature. The idea of using magnets at low temperature leads the new concept of the cryogenic undulators. In this report, the experimental results of the radiation damage of permanent magnets at low temperature are shown.  
 
WEPLT108 Diffusion caused by Beam-beam Interactions with Couplings simulation, coupling, luminosity, synchrotron 2104
 
  • K. Ohmi, S. Kamada, K. Oide, M. Tawada
    KEK, Ibaraki
  A system of colliding two beams is strong nonlinear in multi-dimension. In such a system, a symplectic diffusion called Arnold diffusion occurs, with the result that the beams are enlarged and the luminosity is degraded in circular colliders. We discuss the diffusion seen in beam-beam inetraction at a circular accelerator, especially finite crossing angle and/or x-y coupling errors enhance the diffusion.  
 
WEPLT117 Design of a Third Harmonic Superconducting RF System at PLS emittance, storage-ring, vacuum, synchrotron 2125
 
  • E.-S. Kim, M.-H. Chun, H.-G. Kim, K.-R. Kim, I.-S. Park, Y.-U. Sohn, J.S. Yang
    PAL, Pohang
  • J.-K. Ahn, J.-S. Cho
    Pusan National University, Pusan
  A superconducting third harmonic rf system has been designed in the PLS to raise beam lifetime. Expected beam lifetimes verse beam emittance and operational beam current are presented. A multibunch multiparticle tracking simulation is performed to investigate energy spread, bunch-lengthening and beam instabilities due to the rf cavities. The parameters of the designed rf cavity, designed cryogenic system and estimation of heat load are also presented.  
 
WEPLT119 Beam Instabilitiy Studies of BEPC and BEPCII impedance, electron, synchrotron, synchrotron-radiation 2131
 
  • J.Q. Wang, Z.Y. Guo, Y.D. Liu, Q. Qin, Z. Zhao, D.M. Zhou
    IHEP Beijing, Beijing
  BEPC has been well operated for more then 10 years, and it will be upgraded to a double ring electron positron collider using the existing tunnel, namely BEPCII. This paper describes the recent studies on beam instabilities in BEPC for the improvement of its performance as well as for BEPCII. The instabilities caused by impedance and two-stream effect are investigated. The experimental and simulation results are reported.  
 
WEPLT121 Computer Simulation of Equilibrium Electron Beam Distribution in the Proximity of 4th Order Single Nonlinear Resonance resonance, simulation, electron, storage-ring 2137
 
  • T.-S. Ueng, C.-C. Kuo, H.-J. Tsai
    NSRRC, Hsinchu
  • A. Chao
    SLAC, Menlo Park, California
  The beam distribution of particles in an electron storage ring is distorted in the presence of nonlinear resonances. A computer simulation is used to study the equilibrium distribution of an electron beam in the presence of 4th order single nonlinear resonance. The results are compared with that obtained using an analytical approach by solving the Fokker-Planck equation to first order in the resonance strength. The effect of resonance on the quantum lifetime of electron beam is also compared and investigated.  
 
WEPLT141 Beam-power Calibration System for Industrial Electron Accelerators electron, simulation, target, monitoring 2167
 
  • V.L. Uvarov, S.P. Karasyov, V.I. Nikiforov, R.I. Pomatsalyuk, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev
    NSC/KIPT, Kharkov
  Modern electron accelerators for industrial application provide particle energy of up to 10 MeV and beam power of up to 100 kW. Such a beam is ejected into an air using a scanning system. The measuring channel based on a total-absorption calorimeter of flow-type for a beam calibration with respect to energy flow is designed. The processes of beam interaction with the primary measuring converter (a water-cooled beam absorber of especial geometry) were previously studied using a computer simulation. The metering circuit of the channel is made as a stand-alone module with LCD display and control keypad. It performs the operations of temperature measurement at the input and output of the absorber, as well as a water flow-rate determination. The absorbed power is calculated from measured parameters and then is displayed and stored into channel memory using appropriate software. The process is carried out both in off-line mode and under control of the external PC via a serial interface of RS-232 type.  
 
THYCH01 Issues and Challenges for Short Pulse Radiation Production electron, laser, photon, linac 225
 
  • P. Emma
    SLAC/ARDA, Menlo Park, California
  A new generation of light sources are being planned at many locations, pushing the frontiers of brightness, wavelength, and peak power well beyond existing 3rd generation sources. In addition to these large scale improvements there is great interest in extremely short duration pulses into the femtosecond and sub-femtosecond regime. Collective electron bunch instabilities at these scales are severe, especially in consideration of the high-brightness electron bunch requirements. Several new schemes propose very short radiation pulses generated with moderate electron bunch lengths. Such schemes include radiation pulse compression, differential bunch spoiling, staged high-gain harmonic generation, and selective pulse seeding schemes. We will describe a few of these ideas and address some of the electron bunch length limitations, highlighting recent measurements at the Sub-Picosecond Pulse Source (SPPS) at SLAC where <100-fs electron and x-ray pulses are now available.  
Video of talk
Transparencies
 
THOALH01 Bunch Length Measurements at the SLS Linac using Electro-optical Techniques laser, linac, electron, radio-frequency 253
 
  • A. Winter, M. Tonutti
    RWTH, Aachen
  • S. Casalbuoni, P. Schmüser, S. Simrock, B. Steffen
    DESY, Hamburg
  • T. Korhonen, T. Schilcher, V. Schlott, H. Sigg, D. Suetterlin
    PSI, Villigen
  The temporal profile of the electron bunches in the SLS Linac will be determined by means of electro-optical techniques. A mode locked Ti:Sa Laser with 15 fs pulse width is used for coincidence measurements between the laser pulse and the coherent transition radiation (CTR) generated by short electron bunches. Synchronization accuracy of 100 fs rms between the 3 GHz Linac RF and the 81 MHz repetition rate of the laser was achieved, which is important for the optimum time resolution of the applied electro-optical sampling technique. Likewise, a mode locked Nd:YAG laser with 400 ps long pulses will be used for electro-optical autocorrelation measurements between the CTR and the laser pulses. This alternative technique promises single shot capability and requires much relaxed synchronization stability between laser and electron beam.  
Video of talk
Transparencies
 
THOALH02 Development of the Non-invasive Beam-size Monitor using ODR target, electron, emittance, optics 256
 
  • T. Muto, S. Araki, H. Hayano, V. Karataev, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • A. Naumenko, A.P. Potylitsyn
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
  The beam-size monitor based on Optical Diffraction Radiation (ODR) has been developed at the KEK-ATF. Because of its non-invasive nature, the ODR monitor might be one candidate to measure the extreme-low emittance electron beam for future LC?s and x-ray free electron lasers. To evaluate the beam-size, the angular distribution of the ODR emitted by the beam when crossing a slit in a metallic foil was measured. In the first trial, we observed interference patterns between ODR and backgrounds which may be the synchrotron radiation from most nearest bending magnet at the ATF extracted line. By the installation of the ceramic mask in front of our target, this interference was vanished. And comparing with the result of ODR measurements, we installed the wire scanner in the same position of our monitor. In this paper, we will present developments of the ODR monitor with some experimental results.  
Video of talk
Transparencies
 
THOALH03 The Measurements of the Longitudinal Beam Profile on the Preinjector VEPP-5 electron, single-bunch, space-charge, linac 259
 
  • S. Gurov, P.A. Bak, P.V. Logatchev, V. Pavlov, E. Pyata
    BINP SB RAS, Novosibirsk
  • D. Chernousov
    ICKC, Novosibirsk
  For effective work of preinjector VEPP-5 it is necessary 3 ns bunch with charge 1* 1010 electrons from termogun compress to bunch with 40 ps duration on the positron target. A new streak-camera with RF cavity on the main linac frequency is used. Streak-camera with circle scanning allows see 350 ps single light signal with sub-ps resolution. An additional slow scanning can obtain the trochoidal scanning. Thus one can see with picosecond resolution and with less then 1 psec synchronization the train of ten bunches which are spacing by 350psec. The results of worked streak-camera with RF-cavity for circle scanning are presented.  
Video of talk
Transparencies
 
THYLH01 Beam Diagnostics at the VUV-FEL Facility electron, diagnostics, laser, photon 262
 
  • J. Feldhaus, D. Noelle
    DESY, Hamburg
  The free electron laser (FEL) at the TESLA Test facility at DESY will be the first FEL user facility for VUV and soft X-ray radiation down to 6 nm wavelength, the commissioning starts in summer 2004. Commissioning as well as stable FEL operation require a combination of different diagnostic tools for measuring both electron and photon beam parameters, including the full phase space distribution of the bunch charge, exact timing with sub-picosecond resolution, electron and photon beam overlap along the undulator, radiation beam position in the user area 50-70 m behind the undulator, intensity and spectral distribution of the radiation pulses and others. Much effort has been put in the development of instrumentation for measuring the longitudinal bunch charge distribution, for controlling the electron beam orbit along the undulator, and for online monitoring the radiation intensity, position and spectral distribution. This contribution gives an overview of the complete electron and photon beam diagnostics of the FEL facility and focuses particularly on the instrumentation which is crucial or specific for the FEL operation.  
Video of talk
Transparencies
 
THOBLH03 BESSY II Operated as a Primary Source Standard electron, photon, storage-ring, synchrotron 273
 
  • R. Klein, R. Thornagel, G. Ulm
    PTB, Berlin
  The Physikalisch-Technische Bundesanstalt (PTB) is the German National Metrology Institute and responsible for the realization and dissemination of the legal units in Germany. For the realization of the radiometric units in the VUV and X-ray spectral range PTB has been using calculable synchrotron radiation of bending magnets from the BESSY I and BESSY II electron storage rings for more than 20 years. The spectral photon flux of synchrotron radiation can be precisely calculated by Schwinger's theory. Therefore, all the storage ring parameters entering the Schwinger equation have to be measured with low uncertainty which requires a stable and reproducible operation of the storage ring. At BESSY II, PTB has installed all equipment necessary to measure the electron energy, the electron beam current, the effective vertical source size and the magnet induction at the radiation source point as well as all geometrical quantities with low uncertainty. The measurement accuracy for these quantities enables PTB to calculate the spectral photon flux from the visible up to the soft X-ray range with relative uncertainties below 0.4 %. We report on the measurement of the storage ring parameters with low uncertainty.  
Video of talk
Transparencies
 
THPKF013 Terahertz Diagnostics for the Femtosecond X-ray Source at BESSY laser, electron, dipole, undulator 2284
 
  • K. Holldack, S. Khan, R. Mitzner, T. Quast, G. Wustefeld
    BESSY GmbH, Berlin
  A longitudinal electron density modulation caused by femtoslicing in a storage ring is accompanied by a strong broad band coherent THz-light emission between 0.3 and 10 THz at certain synchrotron radiation emitting devices downstream of the interaction region. A technique to use the THz signal for the control of the overlap of laser and electron bunch using fast infrared bolometers is described. A new dedicated THz extraction port at a bending magnet as well as a spectroscopic setup based on a Martin Puplett spectrometer will be commissioned in May 2004 together with the new femtoslicing source at BESSY.

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

 
 
THPKF014 Status of the BESSY II Femtosecond X-ray Source laser, electron, storage-ring, wiggler 2287
 
  • S. Khan, H.-J. Baecker, J. Bahrdt, H.A. Duerr, V. Duerr, W. Eberhardt, A. Gaupp, K. Godehusen, K. Holldack, E. Jaeschke, T. Kachel, D. Krämer, R. Mitzner, M. Neeb, W.B. Peatman, T. Quast, G. Reichardt, M.-M. Richter, M. Scheer, O. Schwarzkopf, F. Senf, G. Wustefeld
    BESSY GmbH, Berlin
  • I. Hertel, F. Noack, W. Sandner, I. Will, N. Zhavarnokov
    MBI, Berlin
  At the BESSY II storage ring, work is in progress to produce X-ray pulses with 50 fs (fwhm) duration and tunable energy and polarization by "femtoslicing" [*].This work includes extensive alterations to the storage ring (one new and one modified undulator, both in the same straight section, three additional dipole magnets, a new IR beamline, and nine meters of new vacuum vessels) and to two beamlines (relocation and new optical designs), as well as the installation of a femtosecond Ti:sapphire laser system. Commissioning is planned for May 2004. This paper reviews the principles and technical implementation of the new femtosecond X-ray source, and reports the status of the project.

* A. Zholentz, M. Zoloterev, Phys.Rev.Lett. 76 (1996), 912

 
 
THPKF015 Compressed Electron Bunches for THz-Generation - Operating BESSY II in a Dedicated Low Alpha Mode optics, electron, sextupole, single-bunch 2290
 
  • G. Wustefeld, J. Feikes, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  For the first time an electron storage ring was operated during regular user shifts in a dedicated 'low alpha' mode, where electron bunches are compressed to 5 times shorter length for THz [*] and short X-ray pulses experiments. The 1 mm rms-long bunches emit powerfull, coherent THz waves, up to 107 times stronger than incoherent radiation. We report on machine set up and operating experience.

* M. Abo-Bakr et al., Phys. Rev. Lett. 88, 254801 (2002)

 
 
THPKF016 The Metrology Light Source of the Physikalisch-Technische Bundesanstalt in Berlin-Adlershof electron, storage-ring, photon, synchrotron 2293
 
  • R. Klein, G. Ulm
    PTB, Berlin
  • M. Abo-Bakr, P. Budz, K. Bürkmann, D. Krämer, J. Rahn, G. Wustefeld
    BESSY GmbH, Berlin
  PTB, the German National Metrology Institute, has gained approval for the construction of a low-energy electron storage ring in the close vicinity of BESSY II, where PTB operates a laboratory for X-ray radiometry. The new storage ring, named 'Metrology Light Source MLS' will be dedicated to metrology and technology development in the UV and EUV spectral range and so will fill the gap that is present since the shut down of BESSY I. The MLS is designed in close cooperation with BESSY and is located adjacent to the BESSY II facility. Construction will start 2004 and user operation is scheduled to begin in 2008. The MLS has a circumference of 48 m, injection will be from a 100 MeV microtron. The electrons energy is ramped to an eligible value in the range from 200 MeV to 600 MeV. 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, provision is taken to operated the MLS in a low alpha mode for the production of coherent synchrotron radiation in the far IR and THz region.  
 
THPKF017 Status of the Synchrotron Light Source DELTA injection, synchrotron, feedback, vacuum 2296
 
  • D. Schirmer, U. Berges, J. Friedl, A. Gasper, M. Grewe, P. Hartmann, R.G. Heine, H. Huck, G. Schmidt, C. Sternemann, M. Tolan, T. Weis, C. Westphal, K. Wille
    DELTA, Dortmund
  Since 1999, the Dortmunder 1.5 GeV electron storage ring DELTA was continuously extended. The facility serves universities and industries as a source of synchrotron radiation on a regional level. The consolidation of the machine was finally completed in 2002. By now, DELTA, operated for 3000 hours per year, has reached a reliability comparable to other facilities in the world. Large improvements have been made in the installation of the beamlines. At present, two undulator beamlines and several dipole beamlines in the range of soft X-rays are in operation. The 5.3 T superconducting asymmetric wiggler (SAW) serves three beamlines in the hard X-ray regime with circular polarized light. Also the accelerator physics research program has been promoted. The vacuum system was revised during the last year to provide extra space for test sections and additional diagnostics. Substantial progress was achieved by SVD based orbit correction and LOCO based optics modelling as well as detailed CBM studies and a new method for fast tune measurements has been implemented. Future developments for machine improvements, such as DSP-based fast local orbit feedback and a frequent injection mode are in preparation.  
 
THPKF018 Study for a Frequent Injection Mode at Delta with Beam Shutters Open injection, storage-ring, feedback, synchrotron 2299
 
  • G. Schmidt, M. Benna, U. Berges, J. Friedl, A. Gasper, M. Grewe, P. Hartmann, R.G. Heine, H. Huck, D. Schirmer, S. Strecker, T. Weis, K. Wille, N. Zebralla
    DELTA, Dortmund
  The Dortmunder Electron Accelerator (DELTA) is a 1.5 GeV synchrotron light source. DELTA is now operated for 3000 h per year including 2000 h beam time for synchrotron radiation use. The maximum beam current is limited by rf power. To increase the average beam current a frequent injection scheme with beam shutters open is discussed for Delta. The peak current is not enlarged but the number of injections is increased to establish a quasi constant beam current. The quasi constant beam current has in addition the advantage of a constant synchrotron radiation heat-load on vacuum chambers and experiments. First tests at Delta have shown the gain in stability of the closed orbit during frequent injection. This article shows the possibility to install a frequent injection mode with beam shutters open during injection at DELTA. The results of measurements and simulations are presented.  
 
THPKF020 Improvements of the Orbit Stability at DORIS III feedback, photon, synchrotron, synchrotron-radiation 2305
 
  • F. Brinker, O. Kaul
    DESY, Hamburg
  Running since 1974, the storage ring DORIS experienced a major modification in 1991 to run as a dedicated synchrotron radiation source since 1993. Since then the increasing requirements of the users on beam stability lead to a series of technical and operational measures to improve the beam conditions. The beam pipe has been mechanically isolated from the magnets, the cooling has been improved and this year a new orbit feedback came to operation which uses positron beam position monitors as well as photon monitors in the beam lines to stabilise the different photon beams. The different measures taken are presented.  
 
THPKF021 Beam Current Limitations in the Synchrotron Light Source PETRA III impedance, vacuum, synchrotron, electron 2308
 
  • R. Wanzenberg, K. Balewski
    DESY, Hamburg
  At DESY it is planned to rebuild the PETRA ring into a synchrotron radiation facility, called PETRA III, in 2007. Different operation modes with single bunch intensities of up-to 5 mA are been considered to serve the needs of the user communities. A first estimate of the impedance budget of PETRA III is given based on analytical models and numerical wakefield calculations of several vacuum chamber elements. The impedance model includes higher order modes (HOMs) of the cavities to cover also multi bunch aspects. The beam current limitations due to multi and single bunch instabilities are discussed. The build up of an electron cloud is also investigated for the option of using a positron beam to generate the synchrotron radiation.  
 
THPKF036 Developments of the FZP Beam Profile Monitor damping, alignment, coupling, background 2353
 
  • N. Nakamura, M. Fujisawa, H. Kudo, H. Sakai, K. Shinoe, H. Takaki, T. Tanaka
    ISSP/SRL, Chiba
  • H. Hayano, T. Muto
    KEK, Ibaraki
  A beam profile monitor based on two Fresnel Zone Plates (FZPs) has been developed at the KEK-ATF damping ring. This monitor can perform real-time imaging of the electron beam with an X-ray imaging optics and the synchrotron radiation and measure the horizontal and vertical beam sizes with a high spatial resolution. A clear electron-beam image with the vertical beam size less than 10 microns was already obtained in the early measurements [*]. Thereafter some of the optical elements, the crystal monochromator, X-ray CCD camera and FZP holders, were improved and an X-ray pinhole mask was installed between the two FZPs for reducing the background of X-rays passing through the MZP (the second FZP). Aberrations due to alignment errors of the FZPs were studied with an analytical approach and a ray-tracing method and vibrations of the optical elements were measured in order to estimate their effects on the system performance. In this paper, we will present developments of the beam profile monitor with results of some beam-size measurements.

* K. Iida et al., Nucl. Instrum. Methods A506, p.41-49 (2003); N. Nakamura et al., Proc. of PAC2003, p.530-532

 
 
THPKF037 Quasi-isochronus Operation at NewSUBARU synchrotron, betatron, emittance, electron 2356
 
  • Y. Shoji, S.H. Hisao, T. Matsubara
    LASTI, Ako-gun, Hyogo
  Quasi-isochronus operation is one of the operation modes of NewSUBARU, a 1.5 GeV VUV storage ring. NewSUBARU has six invert bending magnets to control the momentum compaction factor. The aim of this research is to explore the extreme reduction of electron bunch length by reducing the linear momentum compaction factor. We experimentally reduced the momentum compaction factor from 0.0014 down to less than 10-5, keeping the beam in the ring. The second-order momentum compaction factor was adjusted to almost zero, while keeping the third-order momentum compaction factor positive. The ring was operated at 1.0 GeV. Using a streak camera, the shortest bunch length we observed was 4 ps FWHM. With such a low momentum compaction factor, we expect an energy spreading by betatron oscillation even at the extremely low beam current.  
 
THPKF038 Radiation Damage of Magnet Coils due to Synchrotron Radiation acceleration, synchrotron, synchrotron-radiation, storage-ring 2359
 
  • K. Tsumaki, S. Matsui, M. Oishi, T. Yorita
    JASRI/SPring-8, Hyogo
  • T. Shibata, T. Tateishi
    KOBELCO, Hyogo
  Radiation damage of the equipment in the SPring-8 storage ring tunnel has become a serious problem. In the storage ring, the unnecessary radiation from bending magnets is shielded by absorbers. The equipment around the absorbers was damaged by the scattered radiation from the absorbers. Last year, cooling water leaked from the rubber hose of magnets. It was due to the deterioration of rubber hose caused by synchrotron radiation. We measured the radiation distribution around the storage ring and found that the most high intensity spot was on the magnet coil near the absorbers. If the coils are damaged and the magnets do not work correctly, we need to shut down the storage ring to exchange the magnet coils. To avoid such a situation, we needed to clarify the relation between the radiation damage of the coils and the dose of radiation. We did an acceleration test of the radiation damage of magnet coils. The magnet coils were exposed to the radiation from the bending magnet directly. We observed the degree of damage with changing the doses of radiation. In this paper, we describe about these acceleration tests and test results.  
 
THPKF043 Accelerators Use for Irradiation of Fresh Medicinal Herbs electron, plasma 2371
 
  • R.D. Minea, M.M. Brasoveanu, M.R. Nemtanu, C. Oproiu
    INFLPR, Bucharest - Magurele
  • E. Mazilu, N. Radulescu
    Hofigal S.A., Bucharest - Magurele
  The paper presents the results regarding the electron beam irradiation of fresh Salvia Officinalis and Calendula Officinalis. Irradiation is already a well-known decontamination method, but it received less attention for medicinal plants, especially on fresh herbs. Microbial load behavior, antioxidant activity, and enzymatic inhibition activity were measured for doses between 1 and 50 kGy. Up to 5 kGy, herbs are decontaminated without any important alteration in the active principles, but they loose their fresh aspect easier than non-irradiated ones. The last effect could be useful for the extracting process in which herbs are stressed anyway.  
 
THPKF051 The Status-2004 of the KURCHATOV Center of SR electron, synchrotron, vacuum, optics 2386
 
  • V. Korchuganov, V. Korchuganov, Y.V. Krylov, V.V. Kvardakov, D.G. Odintsov, V. Ushkov, A.G. Valentinov, Y.L. Yupinov, S.I. Zheludeva
    RRC Kurchatov Institute, Moscow
  • M.V. Kovalchuk
    RAS/A.V.Shubnikov, Moscow
  Kurchatov Synchrotron Radiation Source (KCSR) began the work as a first dedicated synchrotron radiation facility in Russia in 1999. The facility includes two storage rings: 450 MeV SIBERIA-1 and 2.5 GeV SIBERIA-2 and is intended for experiments in the range of SR from VUV up to hard X-ray. Large progress was achieved in increasing SIBERIA-2 stored current during last year. Now maximum current at injection energy is more than 220 mA and it equals to 140 mA at operation energy. The SR dose is rising fast and the life time is also grown because of the outgassing of vacuum chamber by SR. Consequently, after the only one electrons accumulation the work during 24 hours on experimental stations becomes possible with SR beams unbroken. Eight experimental stations with SR beam lines and hutches were mounted and are now in routine operation with SR from bending magnets in experimental hall of Siberia-2. We are installing next beam lines there. SIBERIA-1 also has experimental hall with three beam lines and three experimental stations being in operation. The report describes the current work and the plans on the storage rings. It informs about achieved consumer parameters of an electron beam and status of SR stations.  
 
THPKF056 The MAX IV Facility linac, emittance, undulator, lattice 2392
 
  • M. Eriksson, Å. Andersson, M. Bergqvist, M. Brandin, M. Demirkan, G. Georgsson, G. LeBlanc, L.-J. Lindgren, L. Malmgren, H. Tarawneh, E.J. Wallén, S. Werin
    MAX-lab, Lund
  • B. Anderberg
    AMACC, Uppsala
  • S. Biedron, S.V. Milton
    ANL, Argonne, Illinois
  The MAX IV facility is a planned successor of the existing MAX facility. The planned facilty is described below. It consists of two new synchrotron storage rings operated at different electron energies to cover a broad spectral region and one linac injector. The linac injector is also meant to be operated as a FEL electron source. The two rings have similar low emittance lattices and are placed on top of each other to save space. A third UV light source, MAX III, is planned to be transfered to the new facility.  
 
THPKF060 Singapore Synchrotron Light Source– Helios 2 and Beyond electron, synchrotron, plasma, linac 2400
 
  • H.O. Moser, B.D.F. Casse, E.P. Chew, M. Cholewa, C. Diao, S.X.D. Ding, M. Hua, J.R. Kong, Z. Li, S.bin. Mahmood, M.L. Ng, B.T. Saw, S.V.S. Vidyaraj, O. Wilhelmi, J.H.W. Wong, P. Yang, X.J. Yu
    SSLS, Singapore
  SSLS is operating a superconducting 700 MeV electron storage ring to produce synchrotron radiation over a useful spectral range from 10 keV to the far infrared for micro/nanofabrication, phase contrast imaging, surface and nano science with soft X-rays, and hard X-ray diffraction and absorption spectroscopy. An Infrared spectro/microscopy beamline is under construction. Latest results from all beamlines will be presented. SSLS is also working on a conceptual study of a Linac Undulator Light Installation (LIULI) that includes a superconducting miniundulator. Pursuing earlier work* a prototype built by ACCEL is being tested at SSLS and will later serve for FEL studies in cooperation with SSRF at Shanghai.

* A. Geisler, A. Hobl, D. Krischel, H.O. Moser, R. Rossmanith, M. Schillo, First Field Measurements and Performance Tests of a Superconductive Undulator for Light Sources with a Period Length of 14 mm, ASC Conference, Houston, TX, August 2002

 
 
THPKF061 RT-office for Electron Beam, X-ray, and Gamma-ray Dosimetry target, simulation, electron, shielding 2403
 
  • G.F. Popov, V.T. Lazurik, V.M. Lazurik, Y.V. Rogov
    KhNU, Kharkov
  An absorbed dose of electron beam (EB),X-ray (bremsstrahlung), and gamma-ray within the irradiated product is one of the most important characteristic for all industrial radiation-technological processes. The conception for design of the Radiation-Technological Office (RT-Office) - software tools for EB, X-ray, and gamma-ray dosimetry for industrial radiation technologies was developed by authors. RT-Office realize computer technologies at all basic stages of works execution on the RTL using irradiators of EB, X-ray, and gamma-ray in the energy range from 0.1 to 25 MeV. The specialized programs for simulation of EB, X-ray, and gamma-ray processing and for decision of special tasks in dosimetry of various radiation technologies were designed on basis of the RT-Office modules. The use of the developed programs as predictive tools for EB,X-ray, and gamma-ray dose mapping, for optimization of regimes irradiation to receive minimum for dose uniformity ratio, for reducing the volume of routine dosimetry measurements of an absorbed dose within materials at realization of the radiation-technological processes are discussed in the paper.  
 
THPKF062 Comparison of Dose Distribution Prediction in Targets Irradiated by Electron Beams with Dosimetry electron, target, simulation 2406
 
  • G.F. Popov, V.T. Lazurik, V.M. Lazurik, Y.V. Rogov
    KhNU, Kharkov
  • I. Kalushka, Z. Zimek
    Institute of Nuclear Chemistry and Technology, Warsaw
  The features of the absorbed depth-dose distribution (DDD) on boundaries of two contacting materials and material with air irradiated with an electron beam (EB) were predicted by simulation with the software ModeRTL (Modeling of the radiation-technological lines (RTL)). Validation of DDD prediction with dosimetry was fulfilled on the industrial RTL with linear electron accelerator LAE 13/9 at the INCT, Warsaw. Simulation and measurement of boundary effects of DDD were carried out for targets irradiated by scanning EB with energy 10 MeV on moving conveyer. The irradiated materials were represented as parallelepipeds with all sizes greater than range of electrons in material. Cellulose Triacetate (CTA) dosimetric film (FTR-125) in form of strips inserted between materials and air in parallel with an axis of EB was used for dosimetry. Such irradiation setup allows to receive the complete curve of DDD on the boundary of contacting materials by one dosimetric film. The physical regularities for DDD on the boundary of contacting materials predicted by simulation methods were experimentally confirmed. Investigation of those anomalies is necessary in practice to estimate the quality of an irradiation performed on RTL at realization of various industrial EB processing.  
 
THPKF066 Conception of X-ray Source Based on Compact Wakefield Undulator photon, electron, undulator, RF-structure 2415
 
  • A. Opanasenko
    NSC/KIPT, Kharkov
  Study of interaction of bunched charged ultrarelativistic particles with own wakefields in periodic rf structures detects new applications in the area of accelerator physics and technology. Conception of monochromatic X-ray source based on wakefield undulator, WFU, with very short period is presented. In the base of photon generation by the WFU lies a new mechanism of undulator-type radiation emitted by an ultrarelativistic electron bunch that undulates due to non-synchronous spatial harmonics of its wakefields while the bunch moves along a periodic waveguide. The features of the hard radiation and yield of photons depending on waveguide sizes and charge distribution are considered. The creation of the WFU with sub-millimetre periods due to advanced accelerator technology, such as deep X-ray lithography, opens possibilities to obtain high brightness X-rays at employing comparatively low electron energies without external alternative fields. That can have commercial significance for technological and medical applications.  
 
THPKF073 CIRCE, the Coherent InfraRed CEnter at the ALS storage-ring, laser, synchrotron, synchrotron-radiation 2436
 
  • J.M. Byrd, S. De Santis, J.-Y. Jung, M.C. Martin, W.R. McKinney, D.V. Munson, H. Nishimura, D. Robin, F. Sannibale, R.D. Schlueter, M. Venturini, W. Wan, M.S. Zolotorev
    LBNL, Berkeley, California
  CIRCE (Coherent InfraRed Center) is a new electron storage ring to be built at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL). The ring design is optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range. CIRCE operation includes three possible modes: ultra stable CSR, femtosecond laser slicing CSR and broadband SASE. CSR will allow CIRCE to produce an extremely high flux in the terahertz frequency region. The many orders of magnitude increase in the intensity is the basis of our project and enables new kinds of science. The characteristics of CIRCE and of the different modes of operation are described in this paper.  
 
THPKF075 LUX - A Recirculating Linac-based Facility for Ultrafast X-ray Science linac, electron, laser, undulator 2439
 
  • J.N. Corlett, W.A. Barletta, S. De Santis, L.R. Doolittle, W. Fawley, P.A. Heimann, S.R. Leone, D. Li, S.M. Lidia, G. Penn, A. Ratti, M. Reinsch, R.W. Schoenlein, J.W.  Staples, G.D. Stover, S.P. Virostek, W. Wan, R. Wells, R.B. Wilcox, A. Wolski, J.S. Wurtele, A. Zholents
    LBNL, Berkeley, California
  We present design concepts for LUX - a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux VUV-x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1 - 10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and to propagate electron beams carrying nm-scale density modulation in the final stages of cascaded harmonic generation. Synchronization of tens of femtoseconds is achieved by use of an optical master oscillator distributing timing signals over actively stabilized fiber, and generation of rf signals from the optical master oscillator. We describe technical developments in key areas including injection from a high repetition rate rf photocathode gun, lattice design, UV and soft x-ray production by high-gain harmonic generation, a kicker design for rapid transfer of the electron beam between radiator beamlines, lasers systems concepts, and synchronization between experimental pump lasers and the x-ray pulse.  
 
THPKF076 Plan to Upgrade the Advanced Light Source to Top-off Injection Operation injection, septum, brightness, emittance 2442
 
  • D. Robin, B. J. Bailey, K.M. Baptiste, W. Barry, E. Byrne, J.-Y. Jung, S. Kwiatkowski, R.S. Mueller, H. Nishimura, S. Prestemon, S.L. Rossi, F. Sannibale, D. Schlueter, D. Shuman, C. Steier, G.D. Stover, T. Warwick
    LBNL, Berkeley, California
  • R.J. Donahue
    LBNL/ALS, Berkeley, California
  The brightness and thermal stability of the Advanced Light Source (ALS) is lifetime limited. Brightness improvements such as narrower gap insertion devices, smaller emittance coupling, and higher currents all result in short lifetimes. In addition current changes over a fill impact the thermal stability of both the storage ring and beamlines. In order to mitigate these limitations there is a plan to upgrade the injector of the ALS to full energy injection and to operate in a quasi-continuous filling (Top-Off) injection operation. With Top-Off, the ALS will increase its time-averaged current by two, reduce the vertical emmittance, and operate with smaller gap insertion devices. In this paper we describe our upgrade plan.  
 
THPKF078 Coherent Infrared Radiation from the ALS Generated via Femtosecond Laser Modulation of the Electron Beam electron, laser, wiggler, lattice 2448
 
  • A. Zholents, J.M. Byrd, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, M. Venturini, M.S. Zolotorev
    LBNL, Berkeley, California
  Interaction of an electron beam with a femtosecond laser pulse co-propagating through a wiggler at the ALS produces significant modulation of the electron energies within a short ~100 fs slice of the electron bunch. Subsequent propagation of the energy-modulated bunch around the storage ring results in an appearance of a local temporal modulation of the electron density (micro-bunching) due to the dispersion of electron trajectories. The temporal width of this perturbation evolves as the electron bunch propagates around the ring. The shortest modulation, ~50 microns, appears in the ALS sector immediately following the wiggler magnet, and stretches to ~ 500 microns following propagation over 2/3 of a storage ring orbit. The modulated electron bunch emits single-cycle pulses of temporally and spatially coherent infrared light which are automatically synchronized to the laser pulses. The intensity and spectra of the infrared light were measured in two locations in the ring indicated above and were found to be in good agreement with analytical calculations. Ultra-short pulses of coherent infrared radiation are presently used for a fine tuning the laser ? electron beam interaction for generating femtosecond x-ray pulses.  
 
THPKF082 The Completion of SPEAR 3 vacuum, shielding, power-supply, injection 2451
 
  • R.O. Hettel, R. Akre, S. Allison, P. Bellomo, R.M. Boyce, L. Cadapan, R. Cassel, B. Choi, W.J. Corbett, D. Dell'Orco, T. Elioff, I. Evans, R. Fuller, S. Hill, D. Keeley, N. Kurita, J. Langton, G. Leyh, C. Limborg-Deprey, D. Macnair, D.J. Martin, P.A. McIntosh, E. Medvedko, C.-K. Ng, I. Nzeadibe, J. Olsen, M. Ortega, G.C. Pappas, S. Park, T. Rabedeau, H. Rarback, A. Ringwall, P. Rodriguez, J.A. Safranek, H.D. Schwarz, B. Scott, J.J. Sebek, S. Smith, T. Straumann, J. Tanabe, A. Terebilo, T.A. Trautwein, C. Wermelskirchen, M. Widmeyer, R. Yotam, K. Zuo
    SLAC/SSRL, Menlo Park, California
  On December 15, 2003, 8 1/2 months after the last electrons circulated in the old SPEAR2 storage ring and 5 days after the beginning of commissioning, the first electrons were accumulated in the completely new SPEAR3 ring. The rapid installation and commissioning is a testimony to the SPEAR3 project staff and collaborators who have built an excellent machine and equipped it with powerful and accessible machine modeling and control programs. The final year of component fabrication, system implementation and testing, the 7-month installation period leading up to the beginning of commissioning, and lessons learned are described.  
 
THPKF084 Emerging Concepts, Technologies and Opportunities for Mezzo-scale Terahertz and Infrared Facilities electron, linac, synchrotron, laser 2454
 
  • S. Chattopadhyay, S.T. Corneliussen, G.P. Williams
    Jefferson Lab, Newport News, Virginia
  Recent advances in particle beam, laser and radiofrequency technologies, combined with innovative concepts and techniques such as energy recovery, coherent synchrotron radiation-induced bunching, laser-particle beam scattering, ultrashort pulse slicing, cw high current and brightness phtoinjectors, ultrafast laser switching and compact engineered end products have opened up new opportunities and vistas in terahertz/infrared radiation sources not available before. Such sources would complement the high energy short wavelength x-ray sources in that they will allow us to probe collective processes and their ?function? in complex systems and materials, in a fashion complementary to probing structure via x-rays. We will outline and give examples of both the scientific reach of such radiation sources as well as examples of a few conceived facilities and techniques worldwide spanning a diversity of spectral, coherence, brightness and application ranges in the long wavelength. Such facilities fall in the category of mezzo-scale facilities, bracketed by table top lasers on one hand and large scale synchrotron radiation sources on the other and offer very unique and directed advances in a few key areas in life, materials, imaging, instrumentation and communication sciences.  
 
THPLT004 Toroidal Cavity Loaded with an Electron Beam synchrotron, electromagnetic-fields, synchrotron-radiation, acceleration 2463
 
  • E.D. Gazazyan, T. Harutyunyan, D.K. Kalantaryan
    YSU, Yerevan
  • V. Kocharyan
    DESY, Hamburg
  Three problems have been considered in this paper: the development of Maxwell's equations strict solution method to define the electromagnetic own values and own functions of the toroidal cavity; the radiation of the charged bunch rotating along the average radius, and, at last, the consideration of the case of a toroid filled with dielectric medium. The peculiarities of this radiation have been investigated as well. We suppose to consider the case when toroid is filled with plasma like a disperse medium.  
 
THPLT008 A Beam Condition Monitor for the Experimental Areas of the LHC beam-losses, proton, monitoring, luminosity 2475
 
  • L. Fernandez-Hernando, L. Fernandez-Hernando, C. Ilgner, A. Oh, H. Pernegger
    CERN, Geneva
  • A. Macpherson
    PSI, Villigen
  • T. Pritchard
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • R. Stone
    Rutgers University, The State University of New Jersey, Piscataway, New Jersey
  The CERN Large Hadron Collider (LHC) will store 2808 bunches per colliding beam, with each bunch consisting of 1·1011 protons at an energy of 7 TeV. If there is a failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor fast increments of fluence rate near the interaction point and, if necessary, to generate an abort signal to the LHC accelerator control to dump the beams. The system is being developed initially for the CMS experiment, but is sufficiently general to find potential applications elsewhere. Due to its high radiation hardness, CVD diamond was chosen for investigation as the BCM sensor. Various samples of CVD diamond have been characterised extensively with both a Sr-90 source and in a high intensity testbeam in order to assess the capabilities of such sensors and to study whether this detector technology is suitable for a BCM system. A selection of results from these investigations is presented.  
 
THPLT025 Using Visible Synchrotron Radiation at the SLS Diagnostics Beamline storage-ring, synchrotron-radiation, synchrotron, diagnostics 2526
 
  • V. Schlott, M. Dach, Ch. David, B. Kalantari, M. Pedrozzi, A. Streun
    PSI, Villigen
  A diagnostics beamline has been set-up at the BX05 bending magnet of the SLS storage ring. It is equipped with a standard bending magnet front end, including two photon beam position monitors (PBPM) for determination of photon beam angle and position as well as a pinhole array monitor for online monitoring of beam size. The visual part of the dipole radiation is transported to an optical lab, where the temporal profile of the storage ring bunches can be measured with a minimal time resolution of 2 ps using a dual sweep, synchrocan streak camera. Simultaneously, beam size and coupling can be measured at 1.8 keV radiation energy with a zome plate monitor overcoming diffraction limitations. This paper describes the beamline design and summarizes the first experimental results.  
 
THPLT027 Optical Transition Radiation Based Beam Diagnostics at the BESSY Synchrotron Radiation Source and FEL Accelerators electron, laser, photon, linac 2532
 
  • T.  Kamps, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  Optical Transition Radiation (OTR) based diagnostics tools are widely used in linear accelerators to measure beam parameters like transverse beam size and emittance. Design ideas for OTR stations in the linac section of the BESSY FEL facility are presented. Several key components will be tested in the transfer lines of the BESSY storage ring. Furthermore a novel type of OTR monitor is introduced which enables the measurement of the transverse overlap of seed laser and electron beam in the undulator sections of the linac based FEL facility. Here a special radiator screen will be used allowing simultaneous imaging of both beams in the same optical readout channel.  
 
THPLT038 The Synchrotron Radiation Interferometer using Visble Light at DELTA synchrotron, synchrotron-radiation, electron, storage-ring 2565
 
  • U. Berges, K. Wille
    DELTA, Dortmund
  Synchrotron radiation sources such as DELTA, the Dortmund electron accelerator, rely on a monitoring system to measure the beam size and emittance with sufficient resolution. The resolution limits of the different types of optical synchrotron light monitors at DELTA have been investigated. The minimum measurable beam size with the standard synchrotron light monitor using visible light at DELTA is appr. 80 μm. Due to this limitation an interferometer was built up and tested using the same beamline in the visible range. A minimum measurable beam size of appr. 8 μm could be obtained, which gives an increased resolution of one order of magnitude with the new system.  
 
THPLT044 Measurement of the Transverse Coherence of the TTF Free Electron Laser undulator, electron, free-electron-laser, laser 2580
 
  • R. Ischebeck, M. Tonutti
    RWTH, Aachen
  • J. Feldhaus, E. Saldin, E. Schneidmiller, K. Tiedtke, R. Treusch
    DESY, Hamburg
  • C. Gerth
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • P. Schmüser
    Uni HH, Hamburg
  • M.V. Yurkov
    JINR, Dubna, Moscow Region
  The transverse coherence is important for many applications of a free electron laser (FEL). It depends on the inner structure of the electron bunch in the undulator, which is difficult to measure. It is therefore essential to determine the coherence properties of the FEL radiation directly. The coherence of the vacuum ultraviolet FEL at the TESLA Test Facility has been measured by recording the diffraction pattern of a double slit and measuring the visibility of the interference fringes. The experimental near field diffraction pattern is compared with a numerical model, taking into account the formation of the FEL radiation, the Fresnel diffraction in the near field zone and effects of the experimental set-up. Diffraction patterns have been recorded at various undulator lengths to measure the evolution of the transverse coherence along the undulator. This is compared to the expected evolution of the transverse radiation modes.  
 
THPLT046 The Synchrotron Radiation Beamline at TTF2 synchrotron, synchrotron-radiation, electron, polarization 2586
 
  • O. Grimm, S. Casalbuoni, L. Fröhlich, O. Peters, J. Rossbach
    DESY, Hamburg
  The VUV-FEL at DESY, Hamburg, will require novel techniques to characterize the longitudinal charge distribution of the electron bunches that drive the free-electron laser. Conventional methods are inadequate at the short bunch lengths that will be obtained. One technique under study uses coherent far-infrared radiation to reconstruct the bunch shape through Fourier analysis of the spectrum. In a first step, a beam line to guide both far-infrared (50-1000 um) and optical synchrotron radiation from one of the bunch compressor magnets of the linear accelerator to a diagnostic station outside of the controlled area is currently under construction. It will also allow a comparison between streak camera and far-infrared measurements for features on length scales above some 100 um (the streak camera resolution). Later, infrared techniques extending to shorter wavelengths, i.e. to shorter bunch lengths, will also be used further downstream the accelerator, employing synchrotron, transition and undulator radiation. The beam line design, measurement principle and first measurements will be presented.  
 
THPLT052 Measurement of Relative Gas Chamber Pressure in Narrow Straight Section Vacuum Vessels by Observing Gas Bremstrahlung vacuum, electron, background, beam-losses 2601
 
  • G.A. Naylor, B. Joly, D. Robinson
    ESRF, Grenoble
  The measurement of gas pressure inside long, small cross section, vacuum vessels is difficult due to the distance between the centre of the vacuum vessel and vacuum gauges (leading to a low vacuum conductance). Following initial chamber installation, significant out-gassing is observed leading to a significant pressure bump within the chamber. A modified beam loss detector has been developed in order to monitor the gamma radiation produced by the collision of the 6GeV electrons in the storage ring with residual gas atoms. The narrow beam of gamma radiation is intercepted at various points by high Z materials in the beam line front-end allowing a radiation shower to be detected outside the vacuum vessel proportional to the gas pressure in the corresponding storage ring straight section. Various locations are considerred and results shown.  
 
THPLT058 Commissioning of the OTR Beam Profile Monitor System at TTF/VUV-FEL Injector emittance, electron, diagnostics, target 2619
 
  • A. Cianchi, L. Catani, E.C. Chiadroni
    INFN-Roma II, Roma
  • M. Castellano, G. Di Pirro
    INFN/LNF, Frascati (Roma)
  • K. Honkavaara
    DESY, Hamburg
  • M. Raparelli
    Università di Roma II Tor Vergata, Roma
  The TESLA Test Facility (TTF) linac at DESY is being extended to an energy of 1 GeV to drive a new Free Electron Laser facility (VUV-FEL)with wavelengths between 100 nm and 6 nm.Beam profile monitors based on optical transition radiation (OTR) are one of the most important electron beam diagnostics tools. The OTR imaging system is designed to measure the transverse beam size and shape with a resolution down to 10 um. The images are digitized by CCD cameras. A network structure allows a simpler topology to connect the large number of cameras (24).This paper considers the commissioning of the OTR beam profile monitors during the first running period of the injector in spring 2004.  
 
THPLT059 Design Study of a Movable Emittance Meter Device for the SPARC Photoinjector emittance, simulation, space-charge, cathode 2622
 
  • A. Cianchi, L. Catani
    INFN-Roma II, Roma
  • M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, M. Ferrario, D. Filippetto, V. Fusco
    INFN/LNF, Frascati (Roma)
  • L. Giannessi, L. Picardi, M. Quattromini, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  Preliminary studies of the SPARC rf gun are planned to obtain an accurate analysis and optimization of the emittance compensation scheme, measuring the beam emittance evolution downstream the RF gun with an appropriate diagnostic system. Since with a space charge dominated beam the use of the quad-scan method is not possible a 1D pepper-pot method will be used. A mask with narrow slits will be mounted on a movable support, spanning a 1.5 m meters region to measure the emittance in several positions and reconstruct its behavior in the post gun section. Numerical simulations of the measurement process, mainly based on PARMELA and TREDI, are used to estimate the achievable accuracy and to optimize the experimental setup. Wake field effects induced by the beam propagation through the long bellows have been also investigated with HOMDYN. Based on these simulations the design of the apparatus, called emittance-meter, has been realized and is under construction at LNF.  
 
THPLT060 An Automatic Beam Characterization Instrument for Proton Therapy Applications proton, monitoring, background, diagnostics 2625
 
  • D. Giove, C. De Martinis, M. Mauri
    INFN/LASA, Segrate (MI)
  • C. Cirrone, G. Cuttone
    INFN/LNS, Catania
  The characterization in the transverse plane of the beam is a fundamental step in the design of a proton therapy facility. In this paper we will describe an automatic system able to measure the transverse profiles of the proton beam used in the Catana facility at LNS-Catania. The system has been designed as an autonomous equipment able to acquire optical images of the beam (after an interaction with a converter) and to elaborate them to extract the relevant parameters. The equipment may be interfaced to the rest of the control system of the facility and to the operator interface to provide high level control and monitoring tools. Operational experience will be discussed and the results so far obtained will be outlined.  
 
THPLT067 Development of Optical Diffraction Radiation Beam Size Diagnostics at KEK Accelerator Test Facility target, diagnostics, laser, photon 2646
 
  • V. Karataev, H. Hayano, T. Muto, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • A. Naumenko, A.P. Potylitsyn
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
  Extremely low emittance high current beam is required for the accelerators of the next generation such as linear collider to achieve a reasonable luminosity. However, up to now there is no a simple non-invasive technique for beam diagnostics. A method based on optical diffraction radiation (ODR) appearing when a charged particle passes through a slit between two semi-planes can be one of the promising approaches. The estimations show that it might be possible to measure the beam size as small as 10mcm for a single shot. For a test of the proposed technique we designed an experimental setup and installed it at the extraction line of the KEK-ATF (1.26GeV beam energy, 1010 e/bunch, rms beam size > 10mcm). The electron beam was moving through a 0.26mm wide slit. We have measured backward ODR angular distribution. We have observed the beam size effect on the measured quantities. The sensitivity to the beam size as small as 20mcm was achieved. However, some undesirable factors such as X-ray background, SR photons coming through the mask slit, big detector angular acceptance have to be reduced. In this case a few micrometers beam size could be measured.  
 
THPLT069 High Speed Beam Loss Monitor and its Deterioration by Radiation beam-losses, kicker, septum, booster 2652
 
  • T. Kawakubo, T. Ishida, T. Sanami
    KEK, Ibaraki
  High speed loss monitor is very useful for tuning and operating the beam in an accelerator, especially in the injection and extraction period. We made a new type loss monitor by connecting a fiber to a photo-multiplier (PMT). In the case that the fiber is made of quartz, the source of the signal is Cherenkov effect. And in the case of scintillation fiber, the signal comes from the scintillation effect. The quartz is much stronger than the scintillator to the radiation, but generating light in the quartz is weaker than scintillator, especially in low energy beam. It is very easy to make this monitor and the fabrication cost is cheap. The monitor can observe the bunch loss with an order of 10 ns. After long time use under high irradiation, the signal of the monitor will decrease. Therefore, we also report the dependence of the signal strength on accumulated radiation in various types of material.  
 
THPLT074 The Beam Loss Monitor System of the J-parc LINAC, 3 GEV RCS and 50 GEV MR beam-losses, linac, extraction, injection 2667
 
  • S. Lee, T. Toyama
    KEK, Ibaraki
  • J. Kishiro
    JAERI/LINAC, Ibaraki-ken
  • M. Tanaka
    JAERI, Ibaraki-ken
  The high intensity beam accelerator complex itself requires the significant progress of design study and hardware R&D. Operational beam intensity should be limited by the beam loss and activation level of the equipment. Once the beam loss exceeds a criterion at outer environment, beam intensity has to be decreased to prevent the further activation. In order to investigate loss mechanism and suppress the beam loss, a beam loss monitor system have been developed for the J-PARC linac, 3 GeV RCS and 50GeV MR. The system will be essential component for beam commissioning, tuning and machine protection in high intensity beam accelerators. The loss monitor system is composed of scintillator, argon-methane/3He gas filled proportional counter and air filled coaxial cable ionization chamber, which detect g-ray, neutron and charged particles induced by lost particle. It is necessary to measure wide dynamic range of loss intensity for various beam energies. To prevent the activation and heat load by intense beam loss, fast time response of loss signals is required. In this paper, construction and application of loss monitor system are described in detail. Preliminary result of demonstration in the KEK-PS and calibration with cobalt 60 g-ray radiation source are also discussed.  
 
THPLT076 Compact X-band (11.424 Ghz) Linac for Cancer Therapy linac, electron, laser, simulation 2670
 
  • N.H. Quyet, K. Dobashi, F. Ebina, M. El-Ashmawy, A. Fukasawa, H. Iijima, H. Ogino, M. Uesaka
    UTNL, Ibaraki
  Since most of medical linacs use S-band frequency, so far, such linacs cannot fit to modern advanced treatment techniques such as Tomotherapy and Stereotactic radiotherapy, which allows physicians to locate the tumor position during treatment time and enable for beam modification based on the real time analysis. Therefore, a new generation of electron linac with the compact size, higher power, higher gradient that can supply the advanced requirements of cancer treatment has been become necessary. X-band frequencies range is one of the suitable frequencies range for design such linacs. In this paper we will describe the possible design of a X-band (11.424 GHz) medical linac with side-coupled standing wave structure which understudying in NERL, The University of Tokyo. We aim to couple the therapy machine to the Compton scattering tunable monochromatic X-ray inspection device to realize the simultaneous inspection/therapy. Detailed design and numerical results are presented.  
 
THPLT083 Femto-second Bunch Length Measurement using the RF Deflector electron, dipole, linac, coupling 2691
 
  • S. Kashiwagi, G. Isoyama, R. Kato, K.K. Kobayashi, Y. Matsui, A. Saeki, J. Yang
    ISIR, Osaka
  • H. Hayano, M. Kuriki
    KEK, Ibaraki
  • M. Kudo, M. Washio
    RISE, Tokyo
  The traveling wave type rf cavities operating in dipole mode (TM110-like) is being developed for a measurement of femto-second electron bunch. The femto-second electron bunch is used the pulse radiolysis experiments for the studies on radiation physics and chemistry with femto-second time resolution. The resonant frequency is tuned to the designing value 2856 MHz, which is accelerating frequency of a photo-injector linac at ISIR Osaka University. Further, we are planning to apply the design of the traveling wave rf deflector to a X-band crab cavities for the Global Linear Collider (GLC) project. In this conference, we will report the design of the traveling wave rf deflector and the result of cold test.  
 
THPLT091 The Synchrotron Radiation Monitor Upgradation in NSRRC synchrotron, booster, synchrotron-radiation, optics 2709
 
  • C.H. Kuo, J. Chen, K.-T. Hsu, S.Y. Hsu, Y.-T. Yang
    NSRRC, Hsinchu
  Synchrotron radiation monitor in the storage has been operated for a long time. This system is upgrading to booster operation now. The basic system includes optics, digital image acquisition, image analysis, compressed image transportation and visualization tools at workstation. The linearity and dynamic of new is discussed for some beam physics study. This system is also supported to the booster by new camera and addition operation. The hardware configuration and software structure will be summarized in this report.  
 
THPLT102 Characteristics of Sealed-off Electron Gun with Wide Beam electron, gun, cathode, vacuum 2727
 
  • V.M. Pirozhenko
    MRTI RAS, Moscow
  • A.N. Korolev, K.G. Simonov
    ISTOK, Moscow Region
  Compact sealed-off electron gun is a new promising type of devices. The gun generates wide beam of electrons with energy up to 200 keV and high peak power in 2-microsecond pulses. The beam is extracted to the atmosphere or a gas through the foil being uniformly distributed over the area of exposure. The gun contains the long ribbon cathode of oxide type, the electrodes for forming required distribution of the beam, the output window with 20-micron titanium foil, the high-voltage ceramic insulator, and the vacuum casing of rectangular shape. The gun is applied in the radiation technology system intended for the treatment of continuously moving tapes with 300 mm width. The gun design provides 10% uniformity of the radiation dose on the tape width.  
 
THPLT122 The Energy Deposition Profile of 0.1-3.0 MeV Electrons in NaCl electron, target, scattering, positron 2756
 
  • V.V. Gann
    NSC/KIPT, Kharkov
  • A.V. Sugonyako, D.I. Vainshtein, H.W. den Hartog
    RUG, Groningen
  An analysis is presented of existing experimental and theoretical data of energy loss profiles and energy deposition in thick targets irradiated with MeV-energy electrons. A simple approximate calculation is proposed for the energy deposition profile of a perpendicular beam of 0.1-3 MeV electrons in matter. The results obtained with this method are in agreement with existing calculated and measured energy absorption profiles for a variety of materials. It will be shown that the build-up phenomenon has a significant effect on the energy deposition profile in thick samples. A systematic experimental investigation of the energy deposition profile of 0.5 MeV electrons in 0.2 - 0.8 mm thick NaCl platelets has been carried out. The distribution of the absorbed dose was determined with differential scanning calorimetry method by measuring either the latent heat of melting of the radiation-induced Na-precipitates or the stored energy.  
 
THPLT140 Commissioning of BL 7.2, the New Diagnostic Beamline at the ALS diagnostics, electron, storage-ring, photon 2783
 
  • F. Sannibale, D. Baum, A. Biocca, N. Kelez, T. Nishimura, T. Scarvie, E. Williams
    LBNL, Berkeley, California
  • K. Holldack
    BESSY GmbH, Berlin
  BL 7.2 is a new beamline at the Advanced Light Source (ALS) dedicated to electron beam diagnostics. The system, which is basically a hard x-ray pinhole camera, was installed on the storage ring in August 2003 and the commissioning with the ALS electron beam followed immediately after. In this paper, the commissioning results are presented together with the description of the relevant measurements performed for the beamline characterization.  
 
THPLT142 A Laser-Based Longitudinal Density Monitor for the Large Hadron Collider laser, synchrotron, photon, monitoring 2789
 
  • S. De Santis, J.F. Beche, J.M. Byrd, P. Datte, M. Placidi, V. Riot, R.W. Schoenlein, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  We report on the development of an instrument for the measurement of the longitudinal beam profile in the Large Hadron Collider. The technique used, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store and display the required information. A 40 MHz laser, phase-locked to the ring radiofrequency system, with a 50 ps pulse length, would be suitable for measuring the dynamics of the core of each of the LHC 2808 bunches in a time span much shorter then the synchrotron period. The same instrument could also monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets ("ghost bunches") as required by the CERN specifications. We also specify the required characteristics of the diagnostic light port in the LHC where our instrument would be installed.

* Presently at Lawrence Livermore National Laboratory.

 
 
THPLT143 Development of an Abort Gap Monitor for the Large Hadron Collider photon, synchrotron, synchrotron-radiation, diagnostics 2792
 
  • S. De Santis, J.F. Beche, J.M. Byrd, M. Placidi, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  The Large Hadron Collider, presently under construction at CERN, requires a monitor of the parasitic charge in the 3.3 ?s long gap in the machine fill structure, referred to as the abort gap, which corresponds to the raise time of the abort kickers. Any circulating particle present in the abort gap at the time of the kickers firing is lost inside the ring, rather than in the beam dump, and can potentially damage a number of the LHC components. CERN specifications indicate a linear density of 6x106 protons over a 100 ns interval as the maximum charge safely allowed in the abort gap at 7 TeV. We present a study of an abort gap monitor, based on a photomultiplier with a gated microchannel plate, which would allow for detecting such low charge densities by monitoring the synchrotron radiation emitted in the superconducting undulator dedicated to the measurement of the longitudinal beam properties. We show results of beam test experiments at the Advanced Light Source using an Hamamatsu 5916U MCP-PMT which indicate that such an instrument has the required sensitivity to meet LHC specifications.  
 
THPLT145 Automated High-power Conditioning of Medical Accelerators medical-accelerators, vacuum, ion, shielding 2795
 
  • S.M. Hanna, S. Storms
    Siemens Medical Solutions USA, Inc., Oncology Care Systems Group, Concord
  Medical accelerators require arc-free operation. Due to high-field emission, arcing and outgasing can occur in high-power accelerators. Therefore, the accelerator?s inner surfaces have to be conditioned before its use at high gradient levels in Radiation Therapy machine. At Siemens, we have developed a techniqu·101 to automatically condition an accelerator waveguide structure by continually inspecting the accelerator running conditions (arcing and vacuum) and stepping up the pulse repetition frequency (PRF) and RF power until reaching maximum power rating. The program implemented also reads, displays, and archives the data it collects along the full process of conditioning.  
 
THPLT147 Beam Halo Monitoring on the CLIC Test Facility 3 electron, photon, monitoring, linac 2801
 
  • T. Lefevre
    NU, Evanston
  • H.-H. Braun, E. Bravin, R. Corsini, A.-L. Perrot, D. Schulte
    CERN, Geneva
  In high intensity accelerators, the knowledge of the beam halo distribution and its generation mechanisms are important issues. In order to study these phenomena, dedicated beam diagnostics must be foreseen. In circular machines, beam halo was monitored by using scrapers and beam loss detectors. In the framework of the CLIC project, beam halo monitoring is currently under development. The proposed device is based on an imaging system and a masking technique, which suppresses the core of the beam to allow direct observation of the beam halo. A first test was performed on the CLIC test facility 3 in 2003. We discuss the performances and the limitations of this technique pointing out our plans for future developments.  
 
THPLT154 Design of an X-ray Imaging System for the Low-Energy Ring of PEP-II photon, positron, dipole, vacuum 2819
 
  • A.S. Fisher, D. Arnett, H. De Staebler, S. Debarger, R.K. Jobe, D. Kharakh, D.J. McCormick, M. Petree, M.C. Ross, J. Seeman, B. Smith
    SLAC, Menlo Park, California
  • J. Albert, D. Hitlin
    CALTECH, Pasadena, California
  • J. Button-Shafer, J.A. Kadyk
    LBNL, Berkeley, California
  An x-ray beam-size monitor for positrons in the low-energy ring (LER) of the PEP-II B Factory at SLAC is being designed to accommodate the present 2-A, 3.1-GeV beam and anticipated currents of up to 4.7 A. The final photon stop of an arc will be rebuilt to pass dipole radiation through cooled apertures to optics 17 m from the source. Zone-plate imaging there can achieve a resolution of 6 microns, compared to 35 for a pinhole camera. Two multilayer x-ray mirrors precede the zone plate, limiting the bandwidth to 1%, in order to avoid chromatic blurring and protect the zone plate. Despite the narrow bandwidth, the zone plate?s larger diameter compared to a pinhole camera allows for a comparable photon flux. We will image all 1700 LER bunches and also measure them individually, searching for variations along the train due to electron-cloud and beam-beam effects, using a scanning detector conceptually derived from a wire scanner. A mask with three narrow slots at different orientations will scan the image to obtain three projections. In one passage, signals from a fast scintillator and photomultiplier will be rapidly digitized and sorted to profile each bunch.  
 
THPLT163 High-temperature Kicker Electrodes for High-beam-current Operation of PEP-II kicker, impedance, feedback, vacuum 2843
 
  • U. Wienands, R. Akre, D.E. Anderson, S. Debarger, K. Fant, D. Kharakh, R.E. Kirby, A. Krasnykh, A. Kulikov, J. Langton
    SLAC, Menlo Park, California
  The strip line electrodes of the kickers used in the transverse bunch-by-bunch feedback systems see significant power deposition by beam and HOM-induced currents. This leads to elevated temperatures of the aluminum electrodes and will ultimately become a limit for the beam current in the Low Energy Ring. Heat is transported to the environment primarily by radiation from the blackened surface of the electrodes. In order to extend the beam-current range of these kickers, new electrodes have been fabricated from molybdenum which are able to run at significantly higher temperature, thus greatly increasing the efficiency of the radiative cooling of the electrodes. Blackening of the electrodes is achieved by oxidation in air at 1000°F using a recipe first applied in aviation research for supersonic aircraft. Emissivity was measured on coupons and a whole electrode to be about 0.6. In addition, the match at the terminations of the electrodes is improved following field calculations and measurements on a model of the kicker.  
 
FRXCH01 Development of High Power Targets target, proton, injection, recirculation 276
 
  • G.S. Bauer
    FZJ/ESS, Jülich
  High power targets are at the very heart of most applications of accelerators to science and technology. With many projects aiming to utilize beams in the multi-megawatt power range, solid targets, in particular stationary ones, become increasingly difficult. Liquid metal targets have become the concept of choice. Designs cover a variety of concepts ranging from free jets to allow extraction of low energy ? highly ionizing radiation (pions and muons) to fully enclosed systems if neutron generation is the main goal. Mercury is often the preferred target material due to its liquid state at room temperature and other favourable properties. Designs aiming at high temperature operation depending on small neutron absorption rely on PbBi as target material. Liquid lithium is proposed for a deuteron stripping target for the IFMIF project. Questions that need to be solved include solid-liquid metal reactions, radiation effects, general liquid metal technology, handling of spallation products as well as design of components and subsystems. In addition, short pulse operation leads to the generation of pressure waves inside the targets and the need to control their consequences.  
Video of talk
Transparencies