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undulator

            
Paper Title Other Keywords Page
MOPKF004 Magnet Sorting Algorithm Applied to the LNLS EPU acceleration, alignment, emittance, damping 303
 
  • X.R. Resende, R.M. Dias
    LNLS, Campinas
  The Brazilian Synchrotron Light Laboratory is about to begin the construction of the first Undulator for its 1.37 GeV electron storage ring. This device will be of the EPU type with a period of 50 milimeters and 22 milimeters minimum magnetic gap. In this work we report on the sorting algorithm applied in the construction of a 10-period undulator prototype.  
 
MOPKF005 Preliminary Results on a Low Emittance Gun Based on Field Emission emittance, electron, alignment, damping 306
 
  • R. Ganter, A.E. Candel, M. Dehler, G.J. Gobrecht, C. Gough, S.C. Leemann, K.L. Li, M. Paraliev, M. Pedrozzi, J.-Y. Raguin, L. Rivkin, V. Schlott, L. Schulz, A. Streun, A. Wrulich
    PSI, Villigen
  The development of a new electron gun with the lowest possible emittance would help reducing the total length and cost of a free electron laser. Recent progresses in vacuum nanoelectronics make field emitter arrays (FEAs) an attractive technology to explore for high brightness sources. Indeed, several thousands of microscopic tips can be deposited on a 1 mm diameter area. Electrons are then extracted by a first grid layer close to tip apex and focused by a second grid layer one micrometer above the tip apex. The typical aperture diameter of this focusing layer is also in the range of one micrometer. The big challenge with FEA, is to achieve good emission homogeneity, we hope to achieve this with diverse conditioning techniques. However if we can achieve a low emittance with FEAs another challenge will be to preserve the emittance during the beam acceleration.  
 
MOPKF006 Enhancements of Top-up Operation at the Swiss Light Source emittance, linac, electron, alignment 309
 
  • B. Kalantari, T. Korhonen, A. Lüdeke, C. Quitmann
    PSI, Villigen
  Since the first experience on 2001, Top-Up is the standard mode of operation at the Swiss Light Source (SLS) for users. In order to fulfill the ongoing demands of machine experts and experiments we have had to add more functionality to the Top-Up mode thus make it more flexible. Some time-resolved experiments require a constant charge in a single isolated bucket in the gap of the normal filling of a bunch train of 80% of the circumference of the storage ring. Therefore the Hybrid application was developed that keeps the beam current distribution constant in this mode. We developed a maintenance mode too, to allow to work continuously on the Linac and booster - for example to optimize injection/extraction - without disturbing the Top-up for user operation. Even beam destructive experiments at the Linac during Top-Up or Hybrid operation are supported, where the Linac can be used synchronously at the times between successive refilling of the storage ring. The flexible control and timing systems at the SLS made these applications feasible. We describe the controls, operation and applications of each of the above functionalities in this paper.  
 
MOPKF008 The BESSY Soft X-ray FEL User Facility emittance, electron, alignment, damping 312
 
  • D. Krämer
    BESSY GmbH, Berlin
  A FEL User Facility for the VUV to soft X-ray spectral range is planned at the BESSY site based on a cascaded HGHG-FEL scheme. Simultaneous operation of 3 - later 5 - FELs fed by a superconducting 2.3 GeV CW linac generates most flexible pulse structures for experiments, while the seeding scheme utilizing Ti:Sa fs-lasers results in ultrashort reproducible circular polarized FEL pulses on a shot to shot basis at a pulse-duration < 20 fs. Peak brilliances in the 1·1031 ph/(s mm2 mrad2 0.1% bw)-regime are feasible. All necessary hardware for the FEL is within existing technology. Future upgrade options, e.g. a superconducting photoinjector, seeding with short wavelength HHG lasers of about 1 fs pulse duration have been considered. A status on the design aspects is given.  
 
MOPKF009 Photoinjector Studies for the BESSY Soft X-ray FEL gun, linac, electron, alignment 315
 
  • F. Marhauser
    BESSY GmbH, Berlin
  A linac driven soft X-Ray FEL facility has been proposed at BESSY with the aim to produce high brilliance photon beams within the energy range of 20eV to 1keV. The driver linac is based on superconducting (sc) L-Band rf-technolgy to enable cw operation of the FEL. As the electron beam emittance directly influence the photon beam characteristics, transverse slice emittances of 1.5pimmmrad are envisaged as a target goal. This demands for a high brilliance laser driven photoinjector rf-gun as electron source. For the first years of operation it is intended to use well known normal conducting (nc) L-Band rf-gun technology thereby restricting the macropulse repetition rate to 1 kHz to cope with the thermal power dissipation. At a later stage the nc rf-gun shall be replaced by a sc rf-gun, which is favoured conceptually as it allows to generate outmost flexible bunch patterns according to the needs of the experiments by fully exploiting the capabilities of the sc linac. This paper details the design considerations for a high power nc rf-gun complemented by results of beam dynamic studies up to the exit of the booster linac using ASTRA. Perspectives for the use of a sc photoinjector gun cavity are addressed.  
 
MOPKF032 Status of the ESRF Insertion Devices wiggler, radiation, damping, alignment 372
 
  • J. Chavanne, C. Penel, B. Plan, F. Revol
    ESRF, Grenoble
  The ESRF insertion devices are the object of a continuous refurbishment in order to follow the changing needs of the beamlines and increase their performances. The successful development of the narrow aperture aluminum chambers pumped by non evaporable getter has resulted in the reduction of the minimum gap from 16 mm to 11 mm . A new set of undulator magnetic assemblies with shorter magnetic periods are being prepared that make use of the lower gap. .A prototype of a new type of revolver undulator support has been completed and successfully tested. Such a structure allows the beamline user to switch between two different undulator periods in less than a minute. Three additional devices will be constructed in 2004. Three new in-vacuum undulators have been installed on the ring. One of them is based on an hybrid magnetic structure and achieves a peak field 20% higher than a pure permanent magnet undulator of identical period. Their main magnetic measurements results and interactions with the stored beam are presented.  
 
MOPKF033 Operational Improvements in the ESRF Injection Complex injection, booster, wiggler, radiation 375
 
  • Y. Papaphilippou, P. Elleaume, L. Farvacque, L. Hardy, G.A. Naylor, E. Plouviez, J.-L. Revol, B.K. Scheidt, V. Serriere
    ESRF, Grenoble
  The ESRF injection complex, comprising a 200MeV linac, a booster accelerator with a top energy of 6GeV and two transfer lines, has been routinely injecting beam to the storage ring since the beginning of its operation. The newly implemented injection with ‘‘front-end open'' triggered several operational improvements in order to maximise the reliability of the complex. A series of diagnostics (sychnotron light monitors, striplines, fast current transformers) were implemented allowing the measurement and monitoring of several components of the injected beam. New optics models were constructed and several application systems as the closed orbit correction or tune measurements have been upgraded. The operational procedures of injection at 100MeV in the booster and the injection efficiency maximisation were renewed and improved. Further developments for the uninterrupted operation of the storage ring during injection, such as the bunch cleaning in the booster were successfully tested.  
 
MOPKF034 Status of the Development of Superconducting Undulators at the ESRF injection, booster, wiggler, radiation 378
 
  • E.J. Wallén, J. Chavanne, P. Elleaume
    ESRF, Grenoble
  This note describes the present status of the development of superconducting undulators at the ESRF. Magnetic models of superconducting undulators suitable for the ESRF storage ring have been developed and evaluated. The superconducting undulators studied are horizontally polarizing undulators with a flat field profile and the vertical physical aperture of the undulator is 6 mm. Both 2D models of the local field in a period of the undulator and 3D models of the complete superconducting undulator, including the end sections and current leads, have been evaluated. The practical limit for the obtainable magnetic field has been estimated from the known performance of superconducting wire available from the cabling industry. This note also describes the conceptual design of the cryostat of the superconducting undulator and estimations of the expected heat load to the cryostat at different filling modes of the storage ring.  
 
MOPKF036 Wideband Infrared FEL injection, booster, wiggler, vacuum 384
 
  • J.-M. Ortega, F. Glotin, R. Prazeres
    LURE, Orsay
  The infrared free-electron laser offers the advantage of a potential large tunability since the FEL gain itself remains subtantially high throughout the infrared spectral range, provided that the electron beam quality remains sufficient at low energy. Moreover, the reflectivity of metal mirrors used in the optical cavity remains close to unity from the near infrared up to the microwave range. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator and other optical cavity elements. The undulator magnetic gap, and thus magnetic chamber inner heigth, cannot be made arbitrarily large since one needs a K parameter sufficiently large to produce a large wavength tunability (typically K > 2). The diffraction losses can however be further reduced by using an elliptical vacuum chamber inside the undulator and elliptical, instead of spherical, mirrors. Then the optical beam is partially guided inside the chamber. Working in this regime at CLIO, we have obtained an FEL tunable from 3 to 120 μm by operating the accelerator between 50 and 14 MeV. This is the largest spectral range ever obtained with a single optical cavity. We plan to use larger mirrors to further reduce the diffraction produced at the edges of the undulator chambers in order to increase the maximum wavelength to approximately 200 μm  
 
MOPKF066 Magnetic Design of a Focusing Undulator for ALPHA-X wiggler, bunching, cathode, gun 464
 
  • B.J.A. Shepherd, J.A. Clarke
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  ALPHA-X is a four-year project shared between several research groups in the UK to build a laser-plasma accelerator and produce coherent short-wavelength radiation in an FEL. The FEL undulator will be a 1.5m long, 100 period permanent magnet device with a minimum gap of 3.5mm and a peak field of 0.7T. To focus the beam inside the undulator, several schemes were examined. In the scheme that was selected, the magnet blocks are designed so that the pole face is an approximation of a parabola. This focuses the beam horizontally and vertically. The magnetic design of the undulator is complete; design of the support structure is well under way. Test pieces have been built to ensure that the clamping arrangement is strong enough to cope with the magnetic forces involved. The complete undulator will be built in late 2004 at Daresbury Laboratory, and tested on-site in the new magnet test facility.  
 
MOPKF067 Comparison of Different Buncher Cavity Designs for the 4GLS ERLP wiggler, bunching, cathode, gun 467
 
  • E. Wooldridge, C.D. Beard, C. Gerth
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • A. Buechner
    FZR/FWFE, Dresden
  A DC photocathode gun is part of the injector of the Energy Recovery Linac Prototype (ERLP) currently built at Daresbury Laboratory. A buncher is required for the ERLP to decrease the bunch length off the gun. Three different single-cell cavity designs were investigated: The Cornell buncher, the Elbe Buncher and an EU cavity without Higher Order Mode (HOM) dampers. The properties of these cavities were studied with the computer codes CST's Microwave Studio and ASTRA. The fundamental frequency and field pattern was investigated in Microwave Studio. The EU cavity had to be scaled from 500MHz as the required frequency for the buncher is 1.3GHz. As the anticipated kinetic energy of the electron beam after the gun is about 350keV a particle tracking code including the space charge forces is mandatory to study the effect of the different buncher cavity designs on the beam dynamics. The particle tracking code ASTRA was used to study the performance of the bunchers for a variety of beam parameters. From these investigations it was found that the three bunchers produce very similar effects on the particle bunch.  
 
MOPKF068 Experimental Study of the Stability Margin with Beam Heating in a Short-Period Superconducting Undulator for the APS wiggler, bunching, cathode, gun 470
 
  • S.H. Kim, C. Doose, R. Kustom, E.R. Moog, K.M. Thompson
    ANL/APS, Argonne, Illinois
  A superconducting undulator with a period of 15 mm is under development at the Advanced Photon Source (APS). The undulator is designed to achieve a peak field on the beam axis of 0.8 T with an 8 mm pole tip gap and an NbTi coilpack current density of 1 kA/mm2. Because of the high current density in the coilpack, the superconducting magnet operates at about 75% of the short sample limit at 4.2K. Additional heat load to the coilpack, mainly due to the image currents and synchrotron radiation from the electron beam in the storage ring, will reduce the stability margin. An experiment was conducted to measure the reduction in the stability margin of the coilpack due to heat load on the beam chamber. The heat load was deposited in a 12-period prototype undulator using thin-film heaters attached to the inner surface of a simulated vacuum chamber. Evaluation of the stability margin based on the experiment and calculations of the beam heating and thermal conduction between the undulator and beam chamber will be discussed.  
 
MOPKF069 Engineering Design of the LUX Photoinjector wiggler, bunching, cathode, gun 473
 
  • J.W.  Staples, S.P. Virostek
    LBNL, Berkeley, California
  • S.M. Lidia
    LBNL/AFR, Berkeley, California
  The photoinjector for the LBNL LUX project, a femtosecond-regime X-ray source, is a room-temperature 1.3 GHz 4-cell structure producing a 10 MeV, nominal 30 psec, 1 nanocoulomb electron bunch at a 10 kHz rate. The first cell is of reentrant geometry, with a peak field of 64 MV/m at the photocathode surface, the geometry of which will be optimized for minimum beam emittance. The high repetition rate and high peak power results in a high average surface power density. The design of the cavity, its cooling structure and power couplers, is coordinated with the configuration of the RF system, including a short, high-power driving pulse and active removal of stored energy after the beam pulse to reduce the average power dissipated in the cavity. An RF and thermal analysis will be presented, along with plans for a high average and peak power test of the first cell.  
 
MOPKF070 Design of Injector Systems for LUX wiggler, bunching, cathode, insertion 476
 
  • S.M. Lidia
    LBNL/AFR, Berkeley, California
  The LUX concept [1] for a superconducting recirculating linac based ultrafast x-ray facility features a unique high-brightness electron beam injector. The design of the injector complex that meets the baseline requirements for LUX are presented. A dual-rf gun injector provides both high-brightness electron beams to drive the cascaded, seeded harmonic generation VUV-soft x-ray FELs as well as the ultra- low-vertical emittance ('flat') beams that radiate in hard x-ray spontaneous emission synchrotron beamlines. Details of the injector complex design and performance characteristics are presented. Contributions by the thermal emittance and optical pulse shaping to the beam emission at the photocathode and to the beam dynamics throughout the injector are presented. Techniques that seek to optimize the injector performance, as well as constraints that prevent straightforward optimization, are discussed.  
 
MOPKF071 Study of Row Phase Dependent Skew Quadrupole Fields in Apple-II type EPUs at the ALS wiggler, bunching, cathode, insertion 479
 
  • C. Steier, S. Marks, S. Prestemon, D. Robin, R.D. Schlueter, A. Wolski
    LBNL, Berkeley, California
  Since about 5 years, Apple-II type Elliptically Polarizing Undulators (EPU) have been used very successfully at the ALS to generate high brightness photon beams with arbitrary polarization. However, both EPUs installed so far cause significant changes of the vertical beamsize, especially when the row phase is changed to change the polarization of the photons emitted. The effect has been measured in detail and turned out to be caused by a row phase dependent skew quadrupole term in the EPUs. Magnetic measurements revealed the same effect for the third EPU to be installed later this year. All measurements to identify and quantify the effect with beam will be presented, as well as results of magnetic bench measurements and numeric field simulations.  
 
MOPKF072 Towards Attosecond X-ray Pulses from the FEL wiggler, bunching, cathode, laser 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.  
 
MOPKF073 Design Study of the Bending Sections between Harmonic Cascade FEL Stages wiggler, cathode, laser, insertion 485
 
  • W. Wan, J.N. Corlett, W. Fawley, A. Zholents
    LBNL, Berkeley, California
  The present design of LUX (linac based ultra-fast X-ray facility) includes a harmonic cascade FEL chain to generate coherent EUV and soft X-ray radiation. Four cascade stages, each consisting of two undulators acting as a modulator and a radiator, respectively, are envisioned to produce photons of approximate wavelengths 48 nm, 12 nm, 4 nm and 1 nm. Bending sections may be placed between the modulator and the radiator of each stage to adjust and maintain bunching of the electrons, to separate, in space, photons of different wavelengths and to optimize the use of real estate. In this note, the conceptual design of such a bending section, which may be used at all four stages, is presented. Preliminary tracking results show that it is possible to maintain bunch structure of nm length scale in the presence of errors, provided that there is adequate orbit correction and there are 2 families of trim quads and trim skew quads, respectively, in each bending section.  
 
MOPKF083 Inverse Free Electron Laser Heater for the LCLS laser, wiggler, gun, electron 512
 
  • R. Carr, L.D. Bentson, P. Bolton, D. Dowell, P. Emma, A. Gilevich, Z. Huang, J.J. Welch, J. Wu
    SLAC, Menlo Park, California
  The LCLS Free Electron Laser employs an RF photocathode gun that yields a 1 nC charge bunch a few picoseconds long, which must be further compressed to yield the high current required for SASE gain. The very cold electron beam from the RF photocathode gun is quite sensitive to microbunching instabilities such as coherent synchrotron radiation (CSR) in the compressor chicanes and longitudinal space charge (LSC) in the linac. These effects can be Landau damped by adding energy spread to the electron bunch prior to compression. We propose to do this by interacting an infrared laser beam with the electron bunch in an undulator added to the LCLS gun-to-linac injector. The undulator is placed in a 4-bend chicane to allow the IR laser beam to propagate co-linearly with the e-beam while it oscillates in the undulator. The IR laser beam is derived from the photocathode gun laser. Simulations presented elsewhere in these proceedings show that the laser interaction damps the microbunching instabilities to a very great extent. This paper is a description of the implementation of the laser heater  
 
MOPKF084 Beam Instabilities in Lepton Ring of eRHIC laser, lepton, wiggler, gun 515
 
  • D. Wang, M. Farkhondeh, C. Tschalaer, J. Van der Laan, F. Wang, A. Zolfaghari, T. Zwart
    MIT/BLAC, Middleton, Massachusetts
  • M. Blaskiewicz, Y. Luo, L. Wang
    BNL, Upton, Long Island, New York
  The eRHIC is a high luminosity lepton-hadron collider planned to be built in Brookhaven National Lab, Upton, New York, USA. The lepton machine of eRHIC is a completely newly designed machine complex to provide highly polarized lepton beams at up to 10 GeV energy for the high luminosity lepton-hadron collisions. This paper decribes major issues of collective effects in this lepton storage ring. Besides conventional impedance-driven instabilities, the electron cloud effects in positron operation and fast beam-ion effects in electron operation are of major conserns. The analytical and numerical estimats for major collective effects are made with different machine operation conditions.  
 
MOPKF085 Design Optimizations of X-ray FEL Facility at MIT lepton, wiggler, cathode, emittance 518
 
  • D. Wang, M. Farkhondeh, W. Graves, J. Van der Laan, F. Wang, T. Zwart
    MIT/BLAC, Middleton, Massachusetts
  • P. Emma
    SLAC, Menlo Park, California
  MIT is exploring the construction of a linac-based x-ray laser user facility on the campus of the Bates Linear Accelerator Center. The facility under consideration would span the wavelength range from 100 to 0.3 nm in the fundamental, move into the hard X-ray region in the third harmonic, and preserve the possibility of an upgrade to even shorter wavelengths. The accelerator configuration would include a high brightness electron gun, a superconducting electron linac and multiple undulators and beam lines to support a growing user community. This paper will present the recent progress on the start-to-end simulations including the parameter optimizations and sensativity analysis.  
 
MOPKF086 Modifications of the LCLS Photoinjector Beamline lepton, wiggler, cathode, damping 521
 
  • C. Limborg-Deprey, D. Dowell, S.M. Gierman
    SLAC, Menlo Park, California
  The LCLS Photoinjector beamline is now in the Design and Engineering stage. The fabrication and installation of this beamline is scheduled for the summer 2006. The Photoinjector will deliver 10 ps long electron bunches of 1nC with a normalized transverse emittance of less than 1 mm.mrad for 80% of the slices constituting the core of the bunch at 135 MeV. In this paper, we describe some modifications of the beamline: new exit energy, additional focusing, insertion of a laser heater. We also describe an alternate tuning which is based on a laser pulse of 20ps. The advantages and drawbacks of this long pulse tuning are reviewed. A comparison of sensitivity to field errors and misalignment between the long pulse tuning and the nominal tuning is given.  
 
MOPKF087 The Cebaf Energy Recovery Experiment: Update and Future Plans lepton, wiggler, cathode, damping 524
 
  • A. Freyberger, K. Beard, S.A. Bogacz, Y.-C. Chao, S. Chattopadhyay, D. Douglas, A. Hutton, L. Merminga, C. Tennant, M. Tiefenback
    Jefferson Lab, Newport News, Virginia
  A successful GeV scale energy recovery demonstration with a high ratio of peak-to-injection energies (50:1) was carried out on the CEBAF (Continuous Electron Beam Accelerator Facility) recirculating superconducting linear accelerator in the spring 2003. To gain a quantitative understanding of the beam behavior through the machine, data was taken to characterize the 6D phase space during the CEBAF-ER (CEBAF with Energy Recovery) experimental run. The transverse emittance and energy spread of the accelerating and energy recovered beams were measured in several locations to ascertain the beam quality preservation during energy recovery. Measurements also included the RF system's response to the energy recovery process and transverse beam profile of the energy recovered beam. One of the salient conclusions from the experiment is that the energy recovery process does not contribute significantly to the emittance degradation. The current status of the data analysis will be presented as well as plans for a GeV scale energy recovery experimental run with current doubling.  
 
MOPLT001 Acceleration of Electrons by Spatially Modulated Laser Wave acceleration, lepton, wiggler, cathode 527
 
  • R.A. Melikian, M.L. Petrosyan, V.S. Pogosyan
    YerPhI, Yerevan
  We study the acceleration of electrons in a system of linearly polarized laser wave, propagating at small angles to the direction of electron motion. The parameters of electron bunch and laser wave are chosen so, that during driving electrons in a band of a wave, the electric field of a wave has not changed the direction. The requirements of deriving of maximum rate of acceleration are found depending on parameters of electronic bunch and laser wave. It is shown, that the dependence of growth of electrons energy from number of light bands has nonlinear character. The influence of light diffraction on process of acceleration is considered. It is shown, that the discussed scheme of acceleration allows a possibility of deriving of high acceleration rate owing to existence of modern powerful lasers.  
 
MOPLT003 Upgrading the LNLS Control System from a Proprietary to a Commercial Communications Environment acceleration, lepton, wiggler, cathode 530
 
  • J.G.R.S. Franco, R.M. Ernits, M. Fernandes, A.F.A. Gouveia, J.R. Piton, M.A. Raulik, F.D.S. Rodrigues
    LNLS, Campinas
  The LNLS Control System was built over a proprietary technology, due to governmental policy of information technology in the mid 80's. This made interfacing to commercial systems difficult, limited the technology transfer to the private sector, required a staff with specific knowledge and reduced the possibility of new implementations on the system. Nowadays, the cost to move all of our hardware to a commercial one is out of our budget. This paper describes a proposal, the viability study and first results to move only the communication interfaces to a commercial environment, keeping most of our hardware unchanged and opening the way to gradually move the system to widely accepted standards, when and if necessary. This solution allows a smooth implementation without long periods of machine shutdown and keeps the possibility to operate the machine concurrently between old and new communication interfaces.  
 
MOPLT004 Control of the LHC 400 MHz RF System (ACS) acceleration, lepton, wiggler, cathode 533
 
  • L. Arnaudon, M.D. Disdier, P.M. Maesen, M.P. Prax
    CERN, Geneva
  The LHC ACS RF system is composed of 16 superconducting cavities, eight per ring. Each ring has two cryomodules, each containing four cavities. Each cavity is powered by a 300 kW klystron. The klystrons are grouped in fours, the klystrons in each group sharing a common 58 kV power converter and HV equipment bunker. The ACS RF control system is based on modern industrial programmable controllers (PLCs). A new fast interlock and alarm system with inbuilt diagnostics has been developed. Extensive use of the FIPIO Fieldbus drastically decreases the cabling complexity and brings improved signal quality, increased reliability and easier maintenance. Features of the implementation, such as system layout, communication and the high level software interface are described. Operational facilities such as the automatic switch on procedure are described, as well as the necessary specialist tools and interfaces. A complete RF chain,including high voltage, cryomodule and klystron is presently being assembled in order to check, as far as possible, all aspects of RF system operation before LHC installation. The experience gained so far in this test chain with the new control system is presented  
 
MOPLT005 An Improved Collimation System for the LHC acceleration, lepton, wiggler, cathode 536
 
  • R.W. Assmann, O. Aberle, A. Bertarelli, H.-H. Braun, M. Brugger, L. Bruno, O.S. Brüning, S. Calatroni, E. Chiaveri, B. Dehning, A. Ferrari, B. Goddard, E.B. Holzer, J.-B. Jeanneret, J.M. Jimenez, V. Kain, M. Lamont, M. Mayer, E. Métral, R. Perret, S. Redaelli, T. Risselada, G. Robert-Demolaize, S. Roesler, F. Ruggiero, R. Schmidt, D. Schulte, P. Sievers, V. Vlachoudis, L. Vos, G. Vossenberg, J. Wenninger
    CERN, Geneva
  • I.L. Ajguirei, I. Baishev, I.L. Kurochkin
    IHEP Protvino, Protvino, Moscow Region
  • D. Kaltchev
    TRIUMF, Vancouver
  • H. Tsutsui
    SHI, Tokyo
  The LHC design parameters extend the maximum stored beam energy 2-3 orders of magnitude beyond present experience. The handling of the high-intensity LHC beams in a super-conducting environment requires a high-robustness collimation system with unprecedented cleaning efficiency. For gap closures down to 2mm no beam instabilities may be induced from the collimator impedance. A difficult trade-off between collimator robustness, cleaning efficiency and collimator impedance is encountered. The conflicting LHC requirements are resolved with a phased approach, relying on low Z collimators for maximum robustness and hybrid metallic collimators for maximum performance. Efficiency is further enhanced with an additional cleaning close to the insertion triplets. The machine layouts have been adapted to the new requirements. The LHC collimation hardware is presently under design and has entered into the prototyping and early testing phase. Plans for collimator tests with beam are presented.  
 
MOPLT006 The New Layout of the LHC Cleaning Insertions acceleration, lepton, wiggler, cathode 539
 
  • R.W. Assmann, O. Aberle, O.S. Brüning, S. Chemli, D. Gasser, J.-B. Jeanneret, J.M. Jimenez, V. Kain, E. Métral, G. Peon, S. Ramberger, C. Rathjen, T. Risselada, F. Ruggiero, L. Vos
    CERN, Geneva
  • D. Kaltchev
    TRIUMF, Vancouver
  The improved LHC collimation system required significant changes in the layout and design of the warm insertion IR7. Requirements for collimation, optics, impedance, vacuum, and additional infrastructure are described and the adopted layout is discussed. Various design principles have been explored during the re-design, ranging from a regular 90 degree lattice and special low impedance lattices to an option with additional warm quadrupole units that could have extended the usable space for collimator installations in the insertion. The various constraints for the optics and cleaning design in the LHC cleaning insertions are summarized. Magnet positions and collimators were moved significantly, such that a good cleaning efficiency was maintained while impedance was reduced by a factor of two. Metallic phase 2 collimators allow a better efficiency than originally achievable and additional scrapers were allocated. The required infrastructure was specified, including a powerful cooling system for the collimators.  
 
MOPLT007 Base Line Design for a Beta-beam Neutrino Facility lepton, wiggler, acceleration, cathode 542
 
  • M. Benedikt, S. Hancock, M. Lindroos
    CERN, Geneva
  The term beta-beam has been coined for the production of pure beams of electron neutrinos or their antiparticles through the decay of radioactive ions circulating in a storage ring. The neutrino source itself consists of a high energy storage ring (gamma ~150), with long straight sections in line with the experiment(s). The radioactive ions (6He and 18Ne) will be produced in an ISOL type target system. Due to the short life times of around 1s at rest, the beam needs to be accelerated as quickly as possible. For this a staged system of accelerators is proposed. The chain starts with a linac followed by a rapid cycling synchrotron for acceleration up to ~300 MeV/u. For further acceleration the existing PS and SPS machines are used. Finally, after acceleration to SPS top energy, the ions are transferred to the decay ring where they are merged with the already circulating bunch through a longitudinal stacking procedure. The base line design of the beta beam facility will be presented and the major design problems encountered as well possible solutions will be discussed.  
 
MOPLT008 The Mechanical Design for the LHC Collimators lepton, wiggler, acceleration, cathode 545
 
  • A. Bertarelli, O. Aberle, R.W. Assmann, E. Chiaveri, T. Kurtyka, M. Mayer, R. Perret, P. Sievers
    CERN, Geneva
  The design of the LHC collimators must comply with the very demanding specifications entailed by the highly energetic beam handled in the LHC: these requirements impose a temperature on the collimating jaws not exceeding 50°C in steady operations and an unparalleled overall geometrical stability of 25micro-m on a 1200 mm span. At the same time, the design phase must meet the challenging deadlines required by the general time schedule. To respond to these tough and sometimes conflicting constraints, the chosen design appeals to a mixture of traditional and innovative technologies, largely drawing from LEP collimator experience. The specifications impose a low-Z material for the collimator jaws, directing the design towards graphite or such novel materials as 3-d Carbon/Carbon composites. An accurate mechanical design has allowed to considerably reduce mechanical play and optimize geometrical stability. Finally, all mechanical studies were supported by in-depth thermo-mechanical analysis concerning temperature distribution, mechanical strength and cooling efficiency.  
 
MOPLT009 The Design of the New Fast Extraction Channel for LHC extraction, lepton, wiggler, acceleration 548
 
  • J. Borburgh, B. Balhan, E.H.R. Gaxiola, B. Goddard, Y. Kadi, J.A. Uythoven
    CERN, Geneva
  The Large Hadron Collider (LHC) project requires the modification of the existing extraction channel in the long straight section 6 of the CERN Super Proton Synchrotron (SPS). The new extraction will be used to transfer protons at 450 Gev/c as well as ions via the 2.8 km long transfer line TI 2 to the clockwise ring of the LHC. As the resonant extraction to the present SPS west area will be stopped after 2004, the electrostatic septa will be replaced by new fast extraction kicker magnets. The girder for the existing DC septa will be modified to accommodate a new septum protection element. Other modifications concern the replacement of a machine quadrupole, a new scheme for the extraction bumpers, new instrumentation and interlocks. The requirements and the design of the new extraction channel will be described as well as the modifications which will mainly be carried out in the long SPS shutdown 2005.  
 
MOPLT012 Collimation in the Transfer Lines to the LHC extraction, lepton, wiggler, acceleration 554
 
  • H. Burkhardt, B. Goddard, Y. Kadi, V. Kain, W.J.M. Weterings
    CERN, Geneva
  The intensities foreseen for injection into the LHC are over an order of magnitude above the expected damage levels. The TI 2 and TI 8 transfer lines between the SPS and LHC are each about 2.5 km long and comprise many magnet families. Despite planned power supply surveillance and interlocks, failure modes exist which could result in uncontrolled beam loss and serious transfer line or LHC equipment damage. We describe the collimation system in the transfer lines that has been designed to provide passive protection against damage at injection. Results of simulations to develop a conceptual design are presented. The optical and physical installation constraints are described, and the resulting element locations and expected system performance presented, in terms of the phase space coverage, local element temperature rises and the characteristics of the beam transmitted into the LHC.  
 
MOPLT013 Fatigue Testing of Materials by UV Pulsed Laser Irradiation extraction, lepton, wiggler, acceleration 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.  
 
MOPLT014 Testing of the LHC Magnets in Cryogenic Conditions: Current Experience and Near Future Outlook extraction, lepton, wiggler, acceleration 560
 
  • V. Chohan, M. Buzio, G. De Rijk, J. Miles, P. Pugnat, V. Remondino, S. Sanfilippo, A.D. Siemko, N. Smirnov, B. Vullierme, L. Walckiers
    CERN, Geneva
  For the Large Hadron Collider under construction at CERN, a necessary and primordial condition prior to its installation is that all the main twin-aperture Dipole and Quadrupole magnets are tested in the 1.9K cryogenic conditions. These tests are not feasible at the manufacturers and hence, are carried out at CERN at a purpose built facility on the site. This presentation will give an overall view of the issues related to the operation of the tests facility. In particular, it will give the goals that need to be met to ensure the magnet integrity and performance and the context & constraints on the test programme. Results accumulated from the tested magnets and the ensuing tests stream-lining will be presented, together with some of the explanations and hard limits. Finally, some improvements planned for efficient operation will be given within the confines of the testing programme as was foreseen and the project goals and deadlines.  
 
MOPLT015 Reliability Issues of the LHC Beam Dumping System lepton, wiggler, acceleration, cathode 563
 
  • R. Filippini, E. Carlier, B. Goddard, J.A. Uythoven
    CERN, Geneva
  The Beam Dumping System of the Large Hadron Collider, presently under construction at CERN, must function with utmost reliability to protect the personnel, minimize the risk of severe damage to the machine and avoid undue impact to the environment. The dumping action must be synchronized with the particle free gap and the field of the extraction and dilution elements must be well adjusted to the beam energy. The measures taken to arrive at a reliable and safe system will be described, like the adoption of fault tolerant design principles and other safety related features as comprehensive monitoring, diagnostics and protection facilities. These issues will be discussed in the general framework of the IEC standard recommendations for safety critical systems. Some examples related to the most critical functions will be included.  
 
MOPLT016 Upgrade and Tests of the SPS Fast Extraction Kicker System for LHC and CNGS extraction, lepton, wiggler, acceleration 566
 
  • E.H.R. Gaxiola, A. Antoine, P. Burkel, E. Carlier, F. Castronuovo, L. Ducimetière, Y. Sillanoli, M. Timmins, J.A. Uythoven
    CERN, Geneva
  A fast extraction kicker system has been installed in the SPS and successfully used in extraction tests in 2003. It will serve to send beam to the anticlockwise LHC ring and the CNGS neutrino facility. The magnets and pulse generators have been recuperated from an earlier installation and upgraded to fit the present application. Hardware improvements include diode stacks as replacement of the previous dump thyratron switches, a cooling system of the magnets, sensors for its ferrite temperatures and magnetic field quality assessment. In preparation of the future use for 450 GeV/c transfer to LHC and double batch extraction at 400 GeV/c for CNGS the tests comprised extractions of single bunches, twelve bunches in a single extraction and single bunches in a double extraction. The simulated and measured kick characteristics of the upgraded system are presented, along with results from uniformity calculations of the magnetic field after the modifications to accommodate the cooling circuitry. Further improvements will be discussed which are intended to make the system comply with the specifications for CNGS.  
 
MOPLT017 Beam Commissioning of the SPS LSS4 Extraction and the TT40 Transfer Line lepton, wiggler, acceleration, cathode 569
 
  • B. Goddard, P. Collier, M. Lamont, V. Mertens, K. Sigerud, J.A. Uythoven, J. Wenninger
    CERN, Geneva
  The new fast extraction system in LSS4 of the SPS and the transfer line TT40 were installed between 2000 and 2003, and commissioned with beam in late 2003. The extraction system and transfer line will serve both the anti-clockwise ring of the Large Hadron Collider (LHC), and the long baseline neutrino (CNGS) facility. The layout and functionality of the main elements are briefly explained, including the various hardware subsystems and the controls system. The safety procedures, test objectives and results of the system commissioning with beam are described, together with the test methodology. Conclusions are drawn concerning the performance of the system elements, agreement between predicted and expected activation levels and test efficiency and procedures. The test results are also briefly discussed in the context of future LHC beam commissioning activities.  
 
MOPLT018 Aperture and Delivery Precision of the LHC Injection System injection, lepton, wiggler, acceleration 572
 
  • B. Goddard, M. Gyr, J.-B. Jeanneret, V. Kain, M. Lamont, V. Maire, V. Mertens, J. Wenninger
    CERN, Geneva
  The main LHC injection elements in interaction regions 2 and 8 comprise the injection septa (MSI), the injection kicker (MKI), together with three families of passive protection devices (TDI, TCDD and TCLI). The apertures of the injection septa for the injected and two circulating beams are detailed with a new enlarged vacuum chamber and final septum alignment. The circulating beam aperture of the TDI is detailed with a new TDI support design and modified vacuum tank alignment. A modified TCDD shape is also presented and the implications for the aperture and protection level discussed. The various errors in the SPS, the transfer lines and the injection system, which contribute to injection errors, are analysed, and the expected performance of the system is derived, in terms of the expected delivery precision of the injected beam.  
 
MOPLT019 Experience Gained in the SPS for the Future LHC Abort Gap Cleaning lepton, wiggler, acceleration, cathode 575
 
  • W. Höfle
    CERN, Geneva
  Abort gap cleaning using a transverse damper (feedback) has been previously shown in the RHIC accelerator. We report on experimental results in the SPS, where the transverse damper was used to excite transverse oscillations on part of an LHC test beam, and by the induced losses, creating a practically particle free zone. It is proposed to use the same principle for abort gap cleaning in the LHC. For the LHC abort gap cleaning may be required at injection energy, during the ramp and at top energy. It is shown how the transverse excitation can be optimized taking into account the actual bandwidth of the damper systems and the possibility to fully modulate their input signal to match the beam batatron tune distribution. The cleaning efficiency and speed is estimated considering the porcesses involved, the cleaning (with damper) and the filling of the abort gap.  
 
MOPLT020 Limits to the Performance of the LHC with Ion Beams lepton, wiggler, acceleration, cathode 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.  
 
MOPLT021 Attenuation and Emittance Growth of 450 GeV and 7 TeV Proton Beams in Low-Z Absorber Elements lepton, wiggler, acceleration, injection 581
 
  • V. Kain, B. Goddard, Y. Kadi, R. Schmidt
    CERN, Geneva
  The intensity of the LHC beams will be several orders of magnitude above the damage thresholds for equipment, at 7 TeV, but also already at injection energy of 450 GeV. Passive protection of the equipment against failures during beam transfer, injection and dumping of the beam with absorbers and collimators is foreseen to ensure safe operation. Since these protection devices must be robust in case of beam impact, low-Z materials such as graphite are favored. The reduction of the energy density of the primary beam by the absorber is determined by the attenuation of the beam due to nuclear collisions and the emittance growth of the surviving protons due to scattering processes. Absorbers with low density materials tend to be several meters long to ensure sufficient reduction of the transverse energy density of the impacting beam. The physics principles leading to attenuation and emittance growth for a hadron beam traversing matter are summarised, and FLUKA simulation results for 450 GeV and 7TeV proton beams on low-Z absorbers are compared with theoretical predictions. Design criteria for the LHC absorbers can be derived from these results. As an example, for the transfer line from SPS to LHC a short, low-Z absorber has been proposed to protect the LHC injection elements.  
 
MOPLT022 The Expected Performance of the LHC Injection Protection System lepton, wiggler, acceleration, injection 584
 
  • V. Kain, O.S. Brüning, L. Ducimetière, B. Goddard, M. Lamont, V. Mertens
    CERN, Geneva
  The passive protection devices TDI, TCDD and TCLI are required to prevent damage to the LHC in case of serious injection failures, in particular of the MKI injection kicker. A detailed particle tracking, taking realistic mechanical, positioning, injection, closed orbit and local optical errors into account, has been used to determine the required settings of the absorber elements to guarantee protection against different MKI failure modes. The expected protection level of the combination of TDI with TCLI, with the new TCLI layout, is presented. Conclusions are drawn concerning the expected damage risk level.  
 
MOPLT023 Electron Model of an FFAG Muon Accelerator lepton, wiggler, injection, cathode 587
 
  • E. Keil
    CERN, Geneva
  • J.S. Berg
    BNL, Upton, Long Island, New York
  • A. Sessler
    LBNL, Berkeley, California
  Parameters are derived for the lattice and RF system of electron models of a non-scaling FFAG ring for accelerating muons. The models accelerate electrons from about 10 to about 20 MeV, and have circumferences between 10 and 17 m. Magnet types and dimensions, spacings, half apertures, about 12~mm by 20~mm,and number of cells are presented. The magnetic components are compared to existing magnets. The tune variation with momentum covers several integers, similar to that in a full machine, and allows the study of resonance crossing. The consequences of misaligned magnets are studied by simulation. The lattices are designed such that transition is at about 15 MeV. The variation of orbit length with momentum is less than 36~mm, and allows the study of acceleration outside a bucket. A 100~mm straight section, in each of the cells, is adequately long for an RF cavity operating at 3 GHz. Hamiltonian dynamics in longitudinal phase space close to transition is used to calculate the accelerating voltage needed. Acceleration is studied by simulation. Practical RF system design issues, e.g. RF power, and beam loading are estimated.  
 
MOPLT024 Flexibility, Tolerances, and Beam-Based Tuning of the CLIC Damping Ring lepton, wiggler, injection, cathode 590
 
  • M. Korostelev, J. Wenninger, F. Zimmermann
    CERN, Geneva
  The present design of the CLIC damping ring can easily accommodate anticipated CLIC parameter changes. Realistic misalignments of magnets and monitors increase the equilibrium emittance. In simulations we study both the sensitivity to magnet displacements and the emittance recovery achieved by orbit correction, dispersion-free steering and coupling compensation.  
 
MOPLT025 Status and Plans for the SPS to LHC Beam Transfer Lines TI 2 and TI 8 lepton, wiggler, injection, cathode 593
 
  • V. Mertens, B. Goddard, T. Risselada
    CERN, Geneva
  Beam transfer from the CERN Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC) will be done through the two transfer lines TI 2 and TI 8, presently under construction, with a combined length of about 5.6 km. The final layout, optics design and correction scheme for these lines will be presented. The requirement of simultaneously matching their geometry and optics with that of the LHC will be treated, including the methodology for alignment of the elements along the line and a proposed solution in the final matching section. After the commissioning of the short transfer line TT40 just upstream of TI 8 in 2003, beam tests of the whole of TI 8 are scheduled for autumn 2004, with the aim to validate many of the new features and mechanisms involved in the future control and operation of these lines. The status of the installation will be described, comprising the progress with infrastructure, services and line elements. An outlook will be given for the work remaining until 2007.  
 
MOPLT026 Equipment Manufacturing and Test Data Tracking for the LHC lepton, wiggler, injection, cathode 596
 
  • E. Manola-Poggioli, S.-A. Chalard, C. Delamare, T. Ladzinski, S. Mallon-Amerigo, P. Martel, S. Petit, T. Pettersson, O. Rademakers Di Rosa, B. Rousseau, A.S. Suwalska, D. Widegren
    CERN, Geneva
  The MTF system was developed at CERN to capture the design, manufacturing and test data of equipment built for LHC. Today, more than 80.000 descriptions of LHC equipment are managed using the MTF. The system handles both production data and non-conformance issues. The acquisition of the equipment data is both an organisational and a technical challenge. On the organisational side many different aspects of production and management have to be taken into account. The LHC equipment suppliers, wherever their production facilities are located, whatever their computer skills or rates of production are, need a user friendly environment to provide the data with a very limited effort on the shop floor. For expensive equipment such as the LHC dipoles a reliable and robust non-conformance methodology must be put in place, the MTF provides the required information technology support tools. The EDMS Service has developed methods, training processes and tools to cope with an extensive use of the system, a use that will grow during the next years until the LHC is installed. This paper presents the experience acquired and the solutions put in place.  
 
MOPLT027 Cold Beam Vacuum Interconnects for the LHC Insertion Regions lepton, wiggler, injection, cathode 599
 
  • D.R. Ramos, D. Chauville, J. Knaster, R. Veness
    CERN, Geneva
  The LHC machine is composed of arcs and insertion regions where superconducting magnets, working at temperatures of 1.9 K and 4.5 K, have flexibly interconnected beam vacuum chambers. These interconnects must respect strict requirements in terms of impedance, aperture, space optimization and reliability. A complete interconnect design was first developed for the arc regions, and from which a total of 20 variants have been created according to the different functional requirements of each pair of cryostats along the machine. All design features and manufacture processes were validated through extensive testing. Manufacture and assembly cost was minimised by using a modular interconnect design, with common components shared among different design variants. A detailed quality assurance structure was implemented in order to achieve the high level of reliability required. This paper presents the layout of cold beam vacuum interconnects along with details of development and testing performed to validate design and integration.  
 
MOPLT028 In-Situ Vibration Measurements of the CTF2 Quadrupoles lepton, wiggler, injection, cathode 602
 
  • S. Redaelli, W. Coosemans
    CERN, Geneva
  The Compact LInear Collider (CLIC), presently under study at the European Organization for Nuclear Research (CERN), aims at colliding high-energy ‘‘nanobeams'' at a luminosity of 1035 cm-2s-1. Vibrations of the lattice elements, if not properly corrected, can result in a loss in performance by creating both unacceptable emittance growth in the linear accelerator and relative beam-beam offsets at the interaction point. Of particular concern are the vibrations induced by the accelerator environment. For example, the circulating water used to cool the lattice quadrupoles will increase magnet vibration levels. In the framework of the CLIC stability study, in-situ measurements of quadrupole vibrations have been performed at the CLIC Test Facility 2 (CTF2) with all accelerator equipment switched on. Since the CTF2 quadrupoles and their alignment support structures are realistic prototypes of those to be used in the CLIC linac, the measurements provide a realistic estimate of the CLIC magnet vibrations in a realistic accelerator working environment.  
 
MOPLT029 All Digital IQ Servo-system for CERN Linacs lepton, wiggler, injection, cathode 605
 
  • A. Rohlev, J. Broere, R. Garoby, I. Kozsar, J. Serrano
    CERN, Geneva
  A VME based control system has been developed and built at CERN for the servo loops regulating the field in linac accelerating structures. It is an all-digital system built on a single VME card, providing digital detection, processing, and modulation. It is foreseen to be used, in different versions, for the needs of both present and future CERN hadron linacs. The first application will be in the energy ramping RF chain of the CERN Heavy Ion Linac (linac 3). In addition to regulating the cavity field, the system incorporates the measurement and control of the cavity resonance as well as an imbedded loop stabilizing the gain and the phase of the final amplifier operating near saturation. The design principle and the experimental results are described.  
 
MOPLT030 Performance Limits and IR Design of a Possible LHC Luminosity Upgrade Based on Nb-Ti SC Magnet Technology lepton, wiggler, injection, cathode 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 lepton, wiggler, injection, cathode 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.  
 
MOPLT032 Breakdown Resistance of Refractory Metals Compared to Copper lepton, wiggler, injection, linac 614
 
  • M. Taborelli, S. Calatroni, M. Kildemo
    CERN, Geneva
  The behaviour of Mo, W and Cu with respect to electrical breakdown in ultra high vacuum has been investigated by means of a capacitor discharge method. The maximum stable electric field and the field enhancement factor, beta, have been measured between electrodes of the same material in a sphere/plane geometry for anode and cathode, respectively. The maximum stable field increases as a function of the number of breakdown events for W and Mo. In contrast, no systematic increase is observed for Cu. The highest values obtained are typically 500 MV/m for W, 350 MV/m for Mo and only 180 MV/m for Cu. This conditioning, found for the refractory metals, corresponds to a simultaneous decrease of beta and is therefore related to the field emission properties of the surface and their modification upon sparking. Accordingly, high beta values and no applicable field increase occur for Cu even after repeated breakdown. The results are in agreement with rf breakdown experiments [*] performed on prototype 30 GHz accelerating structures for the CLIC accelerator.

* W. Wuensch, C. Achard, S. Döbert, H. H. Braun, I. Syratchev, M. Taborelli, I. Wilson, "A Demonstration of High Gradient Acceleration", CERN-AB-2003-048-RF; CLIC-Note-569, Proc. PAC2003.

 
 
MOPLT033 Experimental Studies of Controlled Longitudinal Emittance Blow-up in the SPS as LHC Injector and LHC Test-Bed lepton, wiggler, injection, linac 617
 
  • J. Tuckmantel, T. Bohl, T.P.R. Linnecar, E.N. Shaposhnikova
    CERN, Geneva
  The longitudinal emittance of the LHC beam must be increased in a controlled way both in the SPS and the LHC itself. In the first case a small increase is sufficient to help prevent coupled bunch instabilities but in the second a factor three is required to also reduce intra-beam scattering effects. This has been achieved in the SPS by exciting the beam at the synchrotron frequency through the phase loop of the main RF system using bandwidth-limited noise, a method that is particularly suitable for the LHC which will have only one RF system. We describe the tests that have been done in the SPS both for low and high intensity beams, the hardware used and the influence of parameters such as time of excitation, bandwidth, frequency and amplitude on the resulting blow-up. After taking into account intensity effects it was possible to achieve a controlled emittance increase by a factor of about 2.5 without particle loss or the creation of visible tails in the distribution.  
 
MOPLT034 Possible Causes and Consequences of Serious Failures of the LHC Machine Protection System lepton, wiggler, injection, linac 620
 
  • J.A. Uythoven, R. Filippini, B. Goddard, M. Gyr, V. Kain, R. Schmidt, J. Wenninger
    CERN, Geneva
  The LHC machine protection systems, including the beam dumping system, are designed to ensure that failures leading to serious damage to the LHC during its lifetime are extremely unlikely. These kind of failures have to date been considered as being ?beyond the design case?, for instance requiring a combination of equipment failure and surveillance failure. However, they need to be evaluated to determine the required safety levels of the protection systems. A second objective is to understand if measures can and should be taken to further reduce the probability of such failures, or to minimise their impact. This paper considers various serious failure modes of the different machine protection systems. The probable consequences and possible ameliorating measures of the worst-case scenarios are discussed. The particular case of having a stored beam with an unavailable beam dumping system is mentioned, together with possible actions to be taken in such an event.  
 
MOPLT035 Beam Induced Heating of the SPS Fast Pulsed Magnets lepton, wiggler, linac, dumping 623
 
  • J.A. Uythoven, G. Arduini, T. Bohl, F. Caspers, E.H.R. Gaxiola, T. Kroyer, M. Timmins, L. Vos
    CERN, Geneva
  Fast pulsed magnets with ferrite yokes are used in CERN?s SPS accelerator for beam injection, extraction and excitation for tune measurements. The impedance of the ferrite structures can provoke significant beam induced heating, especially for beams with high peak currents as for LHC operation, even beyond the Curie temperature. The expected heating in the different kicker systems for various operational modes is compared with beam measurements. Estimates of the beam induced power have been derived from measured beam spectra. A fast extraction kicker system has recently been equipped with a cooling system. The measured cooling performance is compared with data from laboratory setups and numerical simulations.  
 
MOPLT037 Simulation of Transient Beam-feedback Interaction with Application to the Extraction of the CNGS Beam from the SPS lepton, wiggler, feedback, linac 626
 
  • E. Vogel, W. Höfle
    CERN, Geneva
  For actual and future high energy proton accelerators, such as the LHC, transverse feedback systems play an essential role in supplying the physics experiments with high intensity beams at low emittances. We developed a simulation model to study the interaction between beam and transverse feedback system in detail, bunch-by-bunch and turn-by-turn, considering the real technical implementation of the latter. A numerical model is used as the nonlinear behavior (saturation) and limited bandwidth of the feedback system, as well as the transient nature at injection and extraction, complicates the analysis. The model is applied to the practical case of the CNGS beam in the SPS accelerator. This beam will be ejected from the SPS in two batches causing residual oscillations by kicker ripples on the second batch. This second batch continues to circulate for some 1000 turns after the first batch has been extracted and oscillations are planned to be damped by the feedback system. It is shown how the model can be extended to the case of transients at injection (LHC), and to include coupled bunch instability effects.  
 
MOPLT038 Conceptual Design of the LHC Beam Dumping Protection Elements TCDS and TCDQ lepton, wiggler, feedback, extraction 629
 
  • W.J.M. Weterings, B. Goddard, B. Riffaud, M. Sans Merce
    CERN, Geneva
  The Beam Dumping System for the Large Hadron Collider, presently under construction at CERN, consists, per ring, of a set of horizontally deflecting extraction kicker magnets, vertically deflecting steel septa, dilution kickers and finally, a couple of hundred metres further downstream, an absorber block. A fixed diluter (TCDS) will protect the septa in the event of a beam dump that is not synchronised with the particle free gap or a spontaneous firing of the extraction kickers which will cause the beam to sweep over the septum. A mobile diluter block (TCDQ) will protect the superconducting quadrupole immediate downstream of the extraction as well as the arc at injection energy and the triplet aperture at top energy from bunches with small impact parameters. The conceptual design of the protection elements will be described, together with the status of the mechanical engineering.  
 
MOPLT039 QCD Explorer Based on LHC and CLIC-1 lepton, wiggler, feedback, extraction 632
 
  • F. Zimmermann, D. Schulte
    CERN, Geneva
  Colliding 7-TeV LHC super-bunches with 75-GeV CLIC bunch trains can provide electron-proton collisions at very high centre-of-mass energies, opening up a new window into QCD. At the same time, this QCD explorer would employ several key components required for both an LHC upgrade and CLIC. We here present a possible parameter set of such a machine, study the consequences of the collision for both beams, and estimate the attainable luminosity.  
 
MOPLT040 Test Results of Superconducting Cavities Produced and Prepared Completely in Industry lepton, wiggler, feedback, extraction 635
 
  • M. Pekeler, S. Bauer, B. Griep, H.P. Vogel, P. vom Stein
    ACCEL, Bergisch Gladbach
  Superconducting cavities for a variety of recent projects are produced and prepared for operation in industry. We report on test results of those cavities produced and prepared at ACCEL. The preparation of the cavities includes chemical treatment (BCP), rinsing with high pressure water and assembly in a clean room. The following cavity types were treated: 400 MHz single cell cavities for LHC, 500 MHz single cell cavities of the Cornell CESR design for our superconducting accelerating modules, 1300 MHz TESLA type cavities, 176 MHz and 160 MHz halfwave resonators and a 352 MHz CH-mode cavity for ion accelaration.  
 
MOPLT041 Production of Superconducting Accelerator Modules for High Current Electron Storage Rings lepton, wiggler, feedback, extraction 638
 
  • M. Pekeler, S. Bauer, B. Griep, M. Knaak, H.P. Vogel, P. vom Stein
    ACCEL, Bergisch Gladbach
  For Diamond Light Source, ACCEL was awarded to produce three more superconducting 500 MHz accelerator modules of the Cornell CESR design. With the already 6 modules produced for Cornell, NSRRC and CLS, this module can now be considered as a kind of standard product. In this paper we describe the basic parameters and guaranteed values of this module and will also report on the performance of delivered modules.  
 
MOPLT046 Overcoming Performance Limitations due to Synchrobetatron Resonances in the HERA Electron Ring background, target, wiggler, extraction 650
 
  • F.J. Willeke
    DESY, Hamburg
  The HERA Electron Ring was suffering from strong synchrobetatron resonances which have been particularly detrimental after the HERA luminosity upgrade because of a reduced sychrotron tune due to stronger transverse focusing and a shift in the damping distribution in favor of transverse damping. It turned out to be most difficult to store a beam at the preferred working point for high electron spin polarization between the 2nd and the 3rd synchro-betatron satellite of the horizontal integer resonance. A comparative study of the resonance strength did not reveal any significant additional disadvantage of the new beam optics. However, a mechanism driven by closed orbit distortions was discovered which can increase the width of the resonance Qx+2Qs=0 by a large factor. This explains the operational difficulties. The remedy against this effect is quite straight forward. The Fourier component of the closed orbit near the horizontal tune must be avoided. This is enforced in HERA operations by rigerous orbit corrections and an orbit feedback system which reproduces well-corrected orbits reliably. Synchrobetatron resonances do not constitute a performance limitation of polarized lepton proton collisions in HERA any more.  
 
MOPLT047 Lattice Design Study for HESR background, wiggler, extraction, scattering 653
 
  • Y. Senichev, S. An, K. Bongardt, R. Eichhorn, A. Lehrach, R. Maier, S. Martin, D. Prasuhn, H. Stockhorst, R. Tölle
    FZJ/IKP, Jülich
  The important feature of High Energy Storage Ring is the combination of phase space cooled beams with internal targets, which allows to reach high luminosities up to 2*1032cm-2s-1. However, the requirement to have the strongly focused beam on the target causes the high chromaticity value on the target straight section and as in result to the squeezing of dynamic aperture after sextupole correction of the chromaticity. Simultaneously, the momentum-compaction factor is one of the most important characteristics of an accelerator, which defines the collective instability threshold. Therefore, the HESR lattice has to have the following features: low or negative momentum compaction factor, dispersion free straight sections, convenient method to correct the chromaticity by the sextupoles, sufficiently large dynamic aperture. In this work we develop lattice, which meets all these requirements for HESR.  
 
MOPLT048 High Current Switch-mode Power Converter Prototype for LHC Project 6kA, 8V background, wiggler, extraction, scattering 656
 
  • E. Jauregi, J.M. Del Río, J.M. Dela Fuente, M. Tellería, J.R. Zabaleta
    JEMA GJ, Lasarte-Oria
  • F. Bordry, V. Montabonnet
    CERN, Geneva
  • E.F. Figueres
    E.T.S.I.I., Valencia
  For the Large Hadron Collider (LHC) accelerator being constructed on the CERN site, very precise variable DC currents are required. The company JEMA had during year 2002, designed, manufactured and tested a power converter prototype according to CERN specifications, particularly demanding in terms of dc stability and dynamic response. The power converter is formed by four sub-converters 8V, 2kA in parallel. Isolation between mains input and magnet load is at high frequency done, 40 kHz, which means a volume reduction and better mains perturbations rejection. IGBT inverter soft switch-mode power conversion in ZVS operation reduces dramatically commutation losses, increasing total efficiency of the power converter. The sub-converter, regulated by a wide band width current loop in ACC mode, follows the current reference calculated by the overall voltage loop, providing a good sharing of the output currents and high output stability. The design of the water cooled power converter, results in a very reduce volume and modular structure, providing the system a very flexible exchangeability. The power converter was tested and accepted by CERN into year 2003, some minor points were left to be adjusted during the pre-series stage.  
 
MOPLT049 A Very High-beta Optics to be used for an Absolute Luminosity Determination with Forward Detectors in ATLAS background, wiggler, extraction, resonance 659
 
  • A. Faus-Golfe
    IFIC, Valencia
  • I. Efthymiopoulos, P. Grafstrom, M. Rijssenbeek
    CERN, Geneva
  • M. Haguenauer
    Ecole Polytechnique, Palaiseau
  Atlas detector at the LHC pursues a number of different approaches to obtain an estimate of the absolute luminosity. Measuring elastic scattering at very small angles (3 mu rad) represents a different and complimentary approach that will improve the precision of the final luminosity estimate. In this paper we show the required very hihg-beta optics, detector acceptance studies, and running conditions and calculated performance for the proposed forward detectors located near the ATLAS interaction region.  
 
MOPLT050 High-beta and Very High-beta Optics for LHC background, wiggler, extraction, resonance 662
 
  • A. Faus-Golfe
    IFIC, Valencia
  • A. Verdier
    CERN, Geneva
  New high-beta and very high-beta optics has been sought in order to find the best possible configuration for measuring total cross section in TOTEM and absolute luminosity in ATLAS. They are based on nominal powering scheme of the low-beta triplet. A list of the various possible solution is given in this report. A particularly interesting solution has been found for a case where the phase advance in both planes at the detector location are close to pi/2.  
 
MOPLT051 Experimental Characterization of PEP-II Luminosity and Beam-beam Performance background, wiggler, extraction, resonance 665
 
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • M.A. Baak
    NIKHEF, Amsterdam
  • J. Seeman, M.K. Sullivan, U. Wienands
    SLAC, Menlo Park, California
  The beam-beam performance of the PEP-II B-Factory has been studied by simultaneously measuring the instantaneous luminosity, the horizontal and vertical e+ and e- beam sizes in the two rings, and the spatial extent of the luminous region as extracted from BaBar dilepton data. These quantities, as well as ring tunes, beam lifetimes and other collider parameters are recorded regularly as a function of the two beam currents, both parasitically during routine physics running and in a few dedicated accelerator physics experiments. They are used to quantify, project, and ultimately improve the PEP-II performance in terms of achieved beam-beam parameters, dynamic-beta enhancement, and current-dependence of the specific luminosity.  
 
MOPLT052 Emittance Growth and Beam Lifetime Limitations due to Beam-beam Effects in e+e- Storage Ring Colliders background, wiggler, extraction, resonance 668
 
  • J. Gao
    LAL, Orsay
  In this paper we give analytical expressions for the maximum beam-beam parameter and related beam-beam limited beam lifetime in e+e- storage ring colliders. After analysing the performances of existing or existed machines, we make some discussions on the parameter choice for the Super-B factory design.  
 
MOPLT053 On Parasitic Crossings and their Limitations to e+e- Storage Ring Colliders background, wiggler, extraction, resonance 671
 
  • J. Gao
    LAL, Orsay
  We treat the problem of parasitic crossing in e+e- storage ring colliders analytically. Analytical formulae for the beam lifetime limited by the combined effects of beam-beam interactions at interaction point and at parasitic crossings are derived, and applied to the by-2 colliding mode of PEP-II low energy ring.  
 
MOPLT054 High Current Operation of Pre-bunching Cavities in the CTF3 Accelerator background, wiggler, extraction, resonance 674
 
  • R. Roux, G. Bienvenu
    LAL, Orsay
  • E. Jensen
    CERN, Geneva
  In the framework of the CLIC studies for a 3 TeV centre of mass linear collider the CLIC Test Facility-3 accelerator (CTF3) is developed to validate the novel concept of CLIC drive beam generation. The front end of the CTF3 linac uses a 140 kV thermionic gun capable to deliver a beam with currents of up to 10 A during 1.5 microseconds. Theμtime structure of this beam is generated with two standing wave single-cell 3 GHz pre-buncher cavities. The high current demands special care in the design of the pre-bunchers to preserve beam quality and transmission. A particular concern was beamloading in the second pre-buncher. In this paper, the design and the conditioning of the pre-bunchers are reported but the main focus is on the commissioning with the electron beam, which showed unexpected results. Indeed, contrary to our expectations, the unbunched beam seems to induce a kind of beamloading in the first pre-buncher while the second one shows none.  
 
MOPLT055 RF Excitation of Linear and Curved Sections of the CRFQ Project background, wiggler, extraction, resonance 677
 
  • D. Davino
    Universita' degli Studi del Sannio, Benevento
  • L. Campajola, V.G. Vaccaro
    Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli
  • M.R. Masullo
    INFN-Napoli, Napoli
  • A. Ruggiero
    BNL, Upton, Long Island, New York
  The Circular Radiofrequency Quadrupole is basically a Linear Radio-Frequency Quadrupole completely bent on a circle. A 30-keV prototype is being presently designed and manufactured for testing of the fundamental principles within the scope of a collaboration between BNL and Italian research centers. The storage ring is made of a proton source, a Linear RfQ section 70 cm long, for injection and matching, and eight Curved sections also each about 70 cm long. The proton beam is provided by a modified RF source with electrostatic acceleration at the emittance, intensity and energy required by the beam dynamics.The design of the initial linear prototype is based on a 4-rods geometry having a beam gap diameter of 10mm, and circular 10mm diameters rods. The sector is placed in a 150mm diameter pipe, making it as a very compact structure. The dimensions of the device are adjusted to resonate at 202.56 MHz. A RF power source will be soon available to test the device. The paper describes the compact RF cells arrangement in the design of the two sections.  
 
MOPLT056 Feasibility Study for a Very High Luminosity Phi-factory background, wiggler, extraction, resonance 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.  
 
MOPLT057 Proposal of a Strong RF Focusing Experiment at DAFNE background, wiggler, extraction, resonance 683
 
  • A. Gallo, D. Alesini, G. Benedetti, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, A. Clozza, G.O. Delle Monache, G. Di Pirro, A. Drago, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, U. Rotundo, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, M. Zobov
    INFN/LNF, Frascati (Roma)
  • E. Levichev, P.A. Piminov
    BINP SB RAS, Novosibirsk
  • C. Pagani
    INFN/LASA, Segrate (MI)
  The strong RF focusing is a recently proposed technique to obtain short bunches at the interaction point in the next generation colliders. A large momentum compaction factor together with a very high RF gradient across the bunch provide a modulation of the bunch length along the ring, which can be minimized at the Interaction Point (IP). No storage ring has been so far operated in such a regime, since it requires uncommonly high synchrotron tune values. In this paper we present the proposal of creating the experimental conditions to study the strong RF focusing in DAFNE. The proposed machine lattice providing the required high momentum compaction value, the upgrade of the RF system including the installation of a multi-cell superconducting cavity, the upgrade of the cryogenic plant and a list of the possible beam experiments are illustrated and discussed.  
 
MOPLT058 Status of CTF3 Stretcher-compressor and Transfer Line background, wiggler, extraction, vacuum 686
 
  • A. Ghigo, D. Alesini, C. Biscari, A. Clozza, A. Drago, A. Gallo, F. Marcellini, C. Milardi, B. Preger, M.A. Preger, C. Sanelli, M. Serio, F. Sgamma, A. Stecchi, A. Stella, M. Zobov
    INFN/LNF, Frascati (Roma)
  • R. Corsini, G. Geschonke
    CERN, Geneva
  The first part of the CTF3 transfer line is under installation. It includes a chicane which, because of its very flexible lattice and large aperture vacuum chamber, can change the bunch length in a wide range. The chicane can be used as a stretcher to lengthen the pulses coming from the linac in order to reduce the coherent synchrotron radiation (CSR) in the recombination rings. A possible use as a bunch compressor is also foreseen in order to make CSR experiments and to characterize beam instrumentation. This paper describes the final design of the vacuum chambers, including beam diagnostics components, and their laboratory tests. The installation status of the magnetic and vacuum chamber components together with the ancillary systems is reported.  
 
MOPLT059 Design Options for the RF Deflector of the CTF3 Delay Loop background, wiggler, vacuum, resonance 689
 
  • F. Marcellini, D. Alesini
    INFN/LNF, Frascati (Roma)
  Injection and extraction of bunch trains in the CTF3 Delay Loop for the recombination between adjacent bunch trains is performed by a specially designed RF deflector. A standing wave structure has been chosen. Three possible solutions have been studied and designed, and a comparative analysis is presented. All of them satisfy the essential requirements of the system up to the maximum foreseen energy with the existing klystron.  
 
MOPLT060 New RF Measuring System for Cavity Characterization background, wiggler, vacuum, resonance 692
 
  • S. Stark, G. Bisoffi, l. Boscagli, V. Palmieri, A.M. Porcellato
    INFN/LNL, Legnaro, Padova
  New computer based mobile measuring system for laboratory and online characterization of superconducting cavities has been put into operation at LNL. The system covers the frequency range from 80 to 350 MHz and represents a reliable, fast and precise instrument for cavity testing. The list of automatic and semiautomatic procedures includes line calibrations, frequency sweep, decay time measurement, Q(Eacc) curve acquisition and pulse conditioning.  
 
MOPLT061 Design Study for Advanced Acceleration Experiments and Monochromatic X-ray Production @ SPARC background, wiggler, vacuum, resonance 695
 
  • L. Serafini, S. Cialdi, R. Pozzoli, M. Romé
    INFN-Milano, Milano
  • D. Alesini, S. Bertolucci, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, M.  Migliorati, C. Milardi, L. Palumbo, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario, M. Zobov
    INFN/LNF, Frascati (Roma)
  • F. Alessandria, A. Bacci, F. Broggi, C. De Martinis, D. Giove, M. Mauri
    INFN/LASA, Segrate (MI)
  • R. Bonifacio, I. Boscolo, C. Maroli, V. Petrillo, N. Piovella
    Universita' degli Studi di Milano, MILANO
  • A. Mostacci
    Rome University La Sapienza, Roma
  We present a design study for an upgrade of the SPARC photo-injector system, whose main aim is the construction of an advanced beam test facility for conducting experiments on high gradient plasma acceleration and for the generation of monochromatic X-ray beams to be used in advanced medical applications and condensed matter physics studies. Main components of the proposed plan of upgrade are: two additional beam lines with interaction regions for synchronized high brightness electron and high intensity photon beams and the upgrade of the SPARC Ti:Sa laser system to reach a multi-TW power level (in excess of 1 J in pulse energy). Results of numerical simulations modeling the interaction of the SPARC electron beam and the counter-propagating laser beam are presented with detailed discussion of the monochromatic X-ray beam spectra generated by Compton backscattering: X-ray energies are tunable in the range 20 to 500 keV, with pulse duration from sub-ps to 30 ps. Preliminary simulations of plasma acceleration of the SPARC electron beam, generated in ultra-short bunches, via the LWF mechanism and with external injection are also shown: experiments of self-injection are also foreseen and illustrated.  
 
MOPLT062 The Design of a Prototype RF Compressor for High Brightness Electron Beams background, wiggler, vacuum, resonance 698
 
  • D. Giove, F. Alessandria, A. Bacci, C. De Martinis, M. Mauri
    INFN/LASA, Segrate (MI)
  • D. Alesini, M. Ferrario, A. Gallo, F. Marcellini
    INFN/LNF, Frascati (Roma)
  • L. Serafini
    INFN-Milano, Milano
  The generation of sub-ps electron bunches with low transverse emittance at nC charge level is a crucial requirement in the design of injectors for short wavelength FEL's. The technique of velocity bunching has been by now experimentally proven in various laboratories, where bunches below the ps bunch length were obtained: however, preservation of a low transverse emittance after the bunch compression is still to be demonstrated. To this aim, the use a slow wave RF structure as a rectilinear compressor has been proposed in the past to overcome the inherent difficulties of magnetic compressors. In this paper we will review the work carried out in the last 2 years and focused on the design a RF compressor based on a 3 GHz slow-wave copper structure. The rationale of the conceptual design along with a description of the main experimental activities will be presented and the future application of such a scheme to the SPARC project will be discussed.  
 
MOPLT063 Reconfigurable Hardware Resources in Accelerator Control Systems background, wiggler, vacuum, resonance 701
 
  • D. Giove, C. De Martinis, M. Mauri
    INFN/LASA, Segrate (MI)
  The development of modern accelerator control systems has taken advantage of the possibility to use standard architecture designs based on the experience gained in industrial applications. Communication buses, board formats, operating systems, network protocols and operator interface software are the main elements of this new approach. In this paper we will discuss the way to apply this method also to the design of electronic boards which call for custom design of particular circuits and capabilities. The use of FPGA based standard modules along with the possibility to customize them using a standard LabVIEW environment to obtain reconfigurable hardware resources will be presented.  
 
MOPLT066 Induction Accelerating Cavity for a Circular Ring Accelerator background, wiggler, vacuum, resonance 704
 
  • K. Torikai, Y.A. Arakida, T. Kono, K. Koseki, E. Nakamura, Y. Shimosaki, K. Takayama, T. Toyama, M. Wake
    KEK, Ibaraki
  • J. Kishiro
    JAERI/LINAC, Ibaraki-ken
  This paper reports details of an induction accelerating cavity employed for induction synchrotron POP experiments [*] using the KEK 12GeV PS. This cavity is the first induction cavity in the history of accelerator that is used in a circular ring. We focus our attention on crucial aspects distinguished from well-know properties of RF cavity. The single cavity is capable of generating an acceleration voltage of 2.5kV with a pulse width of 250ns, which is operated at a repetition　rate in the range of 667kHz - 882kHz. The cavity is driven by its own pulse modulator through a 25m long transmission cable of 125W, the end of which is connected with a matching resistance so as to minimize reflection in a wide range of frequency. Accelerating field characteristics are discussed and matching features of the cavity as a one-to-one transformer are presented. A longitudinal and transverse coupling impedance have been measured using a net-work analyzer.

* K.Takayama et al., 'POP Experiments of the Induction Synchrotron' in this conference

 
 
MOPLT067 KEKB Performance background, wiggler, vacuum, resonance 707
 
  • Y. Funakoshi, K. Akai, K. Ebihara, K. Egawa, A. Enomoto, J. Flanagan, H. Fukuma, K.  Furukawa, T. Furuya, J. Haba, S. Hiramatsu, T. Ieiri, N. Iida, H. Ikeda, T. Kageyama, S. Kamada, T. Kamitani, S. Kato, M. Kikuchi, E. Kikutani, H. Koiso, M. Masuzawa, T. Mimashi, A. Morita, T. Nakamura, H. Nakayama, Y. Ogawa, K. Ohmi, Y. Ohnishi, N. Ohuchi, K. Oide, M. Shimada, S. Stanic, M. Suetake, Y. Suetsugu, T. Sugimura, T. Suwada, M. Tawada, M. Tejima, M. Tobiyama, S. Uehara, S. Uno, S.S. Win, N. Yamamoto, Y. Yamamoto, Y. Yano, K. Yokoyama, M. Yoshida, M. Yoshida, S.I. Yoshimoto
    KEK, Ibaraki
  • F. Zimmermann
    CERN, Geneva
  The KEKB B-Factory is an electron-positron double ring collider working at KEK. Its peak luminosity surpassed 1034 /cm2/sec in May 2003 for the first time in the history of colliders. In this report, we summarize the history of KEKB with an emphasis of recent progress.  
 
MOPLT069 Investigation of Injection for the Low-emittance Lattice with New-6.25 ohm Kicker Magnet System at the Photon Factory injection, background, wiggler, vacuum 710
 
  • A. Ueda, K. Harada, Y. Kobayashi, T. Mitsuhashi
    KEK, Ibaraki
  We installed 6.25ohm traveling-wave kicker magnet in the Photon Factory to obtain a wide acceptance for the injected beam into the low-emittance lattice of the Photon Factory. We investigate the injection for the low-emittance lattice with this 6.25ohm kicker magnet system. Hence we have optical beam diagnostic systems which source point is inside of injection bump, we use this system for the investigation of injection. The pulse shape of the injection bump was measured by the optical beam profile monitor with high-speed gated camera by using a stored beam. The result of pulse shape of injection bump was agreed with the predicted one by using result of magnetic field measurement, and pulse duration was shorter than twice of revolution time. The instantaneous beam profile of injected beam was observed in turn by turn by using the same beam profile monitor system. We measure the turn by turn position of the injected beam from this observation and compare with a simulation. We also observe a smear out of beam oscillation by nonlinear effect from this instantaneous beam profile measurement.  
 
MOPLT070 FFAG as Phase Rotator for the PRISM Project injection, background, wiggler, vacuum 713
 
  • A. Sato, M. Aoki, Y. Arimoto, Y. Kuno, M. Yoshida
    Osaka University, Osaka
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto
  • S. Machida, Y. Mori, C. Ohmori, T. Yokoi, K. Yoshimura
    KEK, Ibaraki
  • S. Ninomiya
    RCNP, Osaka
  A Fixed Field Alternating Gradient (FFAG) ring will be used as a phase rotator in the PRISM project. We report a design of the PRISM-FFAG in this paper. PRISM stands for "Phase Rotated Intense Slow Muon beam". It is a project to realize a super muon beam, which combines high-intensity, low-energy, narrow energy-spread and high purity. Its aimed intensity is about 1011-1012 muons per sec. The muon beam will be provided with a low kinetic energy of 20MeV to optimize for the stopped muon experiments. FFAG has some advantageous characteristics to achieve such superb beam. These are a large momentum (longitudinal) acceptance, a wide transverse acceptance with strong focusing, and synchrotron oscillation, which is needed to perform phase rotation. According to simulations, initial energy spread of 20MeV±40% is reduced down to ±6% after 5 turns of muons in the FFAG ring. In the FFAG ring almost all pions decay into muon, hence extracted beam has extremely low pion contamination. A program to construct the PRISM-FFAG ring has been started. It would be completed by the end of JFY 2005.  
 
MOPLT071 EPICS Based Control System for the KOMAC RF System injection, background, wiggler, vacuum 716
 
  • J.C. Yoon, J. Choi, K.M. Ha, J.H. Kim, J.M. Kim, J.-W. Lee
    PAL, Pohang
  This paper presents the RF control system for Korea Multi-purpose Accelerator Complex (KOMAC). KAERI (Korea Atomic Energy Research Institute) has been performing the project named KOMAC. As the 3nd phase of the project, 20MeV proton accelerating structure is under development. The new design is based on the use of VME based Multi-function modules connected to the specific low level RF Controllers(LLRF) via distributed I/O modules and Serial communication modules. The control system was based on EPICS (Experimental Physics and Industrial Control System) from the end of 2003. Installation and commissioning of the RF module is scheduled on 2004. Control system to integrated the RF System to the KOMAC control system is implemented. Hardware, software and various applications are developed to support the operation of RF Control system. This paper EPICS based control system for KOMAC RF  
 
MOPLT072 Effects of Positrons on Relativistic Solitons in Laser-Plasma Interactions injection, background, wiggler, vacuum 719
 
  • J.B.  Kim, I.S. Ko
    POSTECH, Pohang, Kyungbuk
  • H. Suk
    KERI, Changwon
  An extended 1D kinetic model of relativistic solitons by high power lasers in three species plasmas is suggested and it is applied to analysis on the effects of electron-positron pairs on the solitons. Stability condition of the solitons is derived. The range of parameters for the stable solitons are specified in the frequency-temperature plane. With the creation of electron-positron pairs, relativistic solitons appear stable in wider range of frequencies and temperatures. The regions are expanded toward higher values in overall ranges in the frequency-temperature plane. The stability conditions are affected by the density of positrons. The variation of shapes, peak E-field, and width of the solitons by varying the positron density are analyzed. We discuss the implications of the variation in the soliton on the ion accelerations by it.  
 
MOPLT137 Beam Delivery Layout for the Next Linear Collider acceleration, dipole, beamloading, lattice 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.  
 
MOPLT138 Vibrational Stability of GLC/NLC Linear Collider: Status and R&D Plans acceleration, dipole, beamloading, lattice 863
 
  • A. Seryi, F. Asiri, F. Le Pimpec
    SLAC, Menlo Park, California
  • K. Fujii, T. Matsuda, T. Tauchi, H. Yamaoka
    KEK, Ibaraki
  Luminosity stability of the X-band linear collider will be provided by beam-based train by train steering feedbacks in the linac and at the IP, optional active stabilization of the final doublet, being developed to counteract possible excessive vibration of the detector, and optional fast intratrain feedback that would allow delivering major part of the luminosity while other systems are being commissioned. Control and reduction of the beam jitter originating from vibration of collider components is part of our strategy described in this paper.  
 
MOPLT139 Beam-based Alignment and Beta Function Measurements in PEP-II acceleration, quadrupole, dipole, beamloading 866
 
  • G. Yocky, J. Nelson, M.C. Ross, T.J. Smith, J.L. Turner, M. Woodley
    SLAC, Menlo Park, California
  Careful optics studies and stringent lattice control have been identified as two key components to increasing PEP-II luminosity. An accurate, trusted BPM system is required for both of these strategies. To validate the existing BPM system and to better understand some optical anomalies in the PEP-II rings, an aggressive program of beam-based alignment (BBA) has been initiated. Using a quad-shunt BBA procedure in which a quadrupole?s field strength is varied over a range of beam positions, relative offsets are determined by the BPM readings at which quadrupole field changes no longer induce a closed orbit shift. This procedure was verified in the HER and is well underway in the LER IR. We have found many surprisingly large BPM offsets, some over one centimeter, as well as a number of locations where the current nominal orbit is several millimeters from the quadrupole center. Tune versus quadrupole field data were taken during the BBA process in the LER IR, and the non-linear response in each case is compared to simulation to infer local beta functions.  
 
MOPLT141 IR Upgrade Plans for the PEP-II B-Factory luminosity, acceleration, quadrupole, beamloading 869
 
  • M.K. Sullivan, S. Ecklund, N. Kurita, A. Ringwall, J. Seeman, U. Wienands
    SLAC, Menlo Park, California
  • M.E. Biagini
    INFN/LNF, Frascati (Roma)
  PEP-II, the SLAC, LBNL, LLNL B-factory has achieved a peak luminosity of over 7e33, more than twice the design luminosity, and plans to obtain a luminosity of over 1·1034 in the next year. In order to push the luminosity performance of PEP-II to even higher levels an upgrade to the interaction region is being designed. In the present design, the interaction point is a head-on collision with two strong horizontal dipole magnets (B1) located between 20-70 cm from the IP that bring the beams together and separate the beams after the collision. The first parasitic crossing (PC) is at 63 cm from the IP in the present by2 bunch spacing. The B1 magnets supply all of the beam separation under the present design. Future improvements to PEP-II performance include lowering the beta y * values of both rings. This will increase the beta y value at the PCs which increases the beam-beam effect at these non-colliding crossings. Introducing a horizontal crossing angle at the IP quickly increases the beam separation at the PCs but recent beam-beam studies indicate a significant luminosity reduction occurs when a crossing angle is introduced at the IP. We will discuss these issues and describe the present interaction region upgrade design.  
 
MOPLT142 Analysis of KEK-ATF Optics and Coupling Using LOCO luminosity, acceleration, quadrupole, beamloading 872
 
  • M. Woodley, J. Nelson, M.C. Ross
    SLAC/NLC, Menlo Park, California
  • A. Wolski
    LBNL/AFR, Berkeley, California
  LOCO is a computer code for analysis of the linear optics in a storage ring based on the closed orbit response to steering magnets. The analysis provides information on focusing errors, BPM gain and rotation errors, and local coupling. Here, we discuss the details of the LOCO implementation at the KEK-ATF Damping Ring, and report the initial results. Some of the information obtained, for example on the BPM gain and coupling errors, has not previously been determined. We discuss the possibility of using the data provided by the LOCO analysis to reduce the vertical emittance of the ATF beam.  
 
MOPLT143 Results and Plans of the PEP-II B-Factory luminosity, acceleration, quadrupole, beamloading 875
 
  • J. Seeman, J. Browne, Y. Cai, S. Colocho, F.-J. Decker, M.H. Donald, S. Ecklund, R.A. Erickson, A.S. Fisher, J.D. Fox, S.A. Heifets, R.H. Iverson, A. Kulikov, A. Novokhatski, M.T.F. Pivi, M.C. Ross, P. Schuh, T.J. Smith, K. Sonnad, M. Stanek, M.K. Sullivan, P. Tenenbaum, D. Teytelman, J.L. Turner, D. Van Winkle, U. Wienands, M. Woodley, Y.T. Yan, G. Yocky
    SLAC, Menlo Park, California
  • M.E. Biagini
    INFN/LNF, Frascati (Roma)
  • J.N. Corlett, C. Steier, A. Wolski, M.S. Zisman
    LBNL, Berkeley, California
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • G. Wormser
    IPN, Orsay
  PEP-II is an e+e- B-Factory Collider located at SLAC operating at the Upsilon 4S resonance. PEP-II has delivered, over the past four years, an integrated luminosity to the BaBar detector of over 175 fb-1 and has reached a luminosity over 7.4x1033/cm2/s. Steady progress is being made in reaching higher luminosity. The goal over the next few years is to reach a luminosity of at least 2x1034/cm2/s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, trickle injection, high RF beam loading, lower beta y*, interaction region operation, and coupling control.  
 
MOPLT144 Design for a 1036 Super-B-factory at PEP-II acceleration, quadrupole, beamloading, lepton 878
 
  • J. Seeman, Y. Cai, F.-J. Decker, S. Ecklund, A.S. Fisher, J.D. Fox, S.A. Heifets, A. Novokhatski, M.K. Sullivan, D. Teytelman, U. Wienands
    SLAC, Menlo Park, California
  Design studies are underway to arrive at a complete parameter set for a very high luminosity e+e- Super B-Factory (SBF) in the luminosity range approaching 1036/cm2/s. The design is based on a collider in the PEP-II tunnel but with an upgraded RF system (higher frequency), magnets, vacuum system, and interaction region. The accelerator physics issues associated with this design are reviewed as well as the site and power constraints. Near term future studies will be discussed.  
 
MOPLT146 Trickle-charge: a New Operational Mode for PEP-II luminosity, acceleration, quadrupole, beamloading 881
 
  • J.L. Turner, S. Colocho, F.-J. Decker, S. Ecklund, A.S. Fisher, R.H. Iverson, C. O'Grady, J. Seeman, M.K. Sullivan, M. Weaver, U. Wienands
    SLAC, Menlo Park, California
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  In regular top-up-and-coast operation, PEP-II average luminosity is about 70…75% of the peak luminosity due to detector ramp-down and ramp-up times plus the time it takes to top-up both beams. We recently commissioned a new operational mode where the Low Energy Ring is injected continuously without ramping down the detector. The benefits?increased luminosity lifetime and roughly half the number of top-ups per shift?were expected to give an increase in delivered luminosity of about 15% at the same peak luminosity; this was confirmed in test runs. In routine trickle operation, however, it appears that the increase in delivered luminosity is more than twice that due to an increase in availability credited to the more stable operating conditions during trickle operation. In this paper we will present our operational experience as well as some of the diagnostics we use to monitor and maintain tuning of the machine in order to control injection background and protect the detector. Test runs are planned to extend trickle-charge operation to the High Energy Ring as well.  
 
MOPLT147 SPEAR 3 Commissioning Software luminosity, acceleration, quadrupole, beamloading 884
 
  • W.J. Corbett, G.J. Portmann, J.A. Safranek, A. Terebilo
    SLAC/SSRL, Menlo Park, California
  In order to meet the tight SPEAR 3 accelerator commissioning schedule, a software package was assembled to streamline experimental measurements and data analysis. At the heart of the software is a MATLAB "middle layer" with an element definition database and channel access link for fast and easy communication with the EPICS control system. Originally adapted from work at the ALS, the middle layer allows direct control from the MATLAB command line, use in the form of short "scripts" for specific experiments and integration into high-level application programs. The revised software is also machine-independent. This paper outlines the software architecture and provide examples with results from the SPEAR 3 accelerator commissioning effort.  
 
MOPLT148 Progress of the eRHIC Electron Ring Design electron, acceleration, quadrupole, beamloading 887
 
  • F. Wang, M. Farkhondeh, W. Franklin, W. Graves, R. Milner, C. Tschalaer, J. Van der Laan, D. Wang, A. Zolfaghari, T. Zwart
    MIT/BLAC, Middleton, Massachusetts
  • D.P. Barber
    DESY, Hamburg
  • C. Montag, S. Peggs, V. Ptitsyn
    BNL, Upton, Long Island, New York
  • A.V. Otboev, Y.M. Shatunov
    BINP SB RAS, Novosibirsk
  • J. Shi
    KU, Lawrence, Kansas
  Over the past year, a baseline design of the electron ring for the eRHIC hadron-lepton collider has been developed.This site-specific design is based on the understanding of the existing RHIC machine performance and its possible upgrades.The design includes a full energy polarized electron beam injector to ensure operational reliability and to provide high integrated luminosity.The electron ring energy range is 5 to 10 GeV.The electron beam emittance, the electron beam path length and the interaction region optics have to be adjusted over a wide range to match the hadron beam of various species and variable energies.We describe the expected machine perfomance, the interaction region and the lattice design. We also discuss the possible approaches leading to the 1033 cm-2s-1 luminosity for the collisions between 10 GeV polarized electron beam and 250 GeV polarized proton beam.  
 
MOPLT151 Study of Arc-related RF Faults in the CEBAF Cryomodules acceleration, vacuum, quadrupole, beamloading 890
 
  • E. Daly, D. Curry, J. Musson, G. Myneni, T. Powers, H. Wang, T.E. Whitlatch
    Jefferson Lab, Newport News, Virginia
  • I.E. Campisi
    ORNL/SNS, Oak Ridge, Tennessee
  A series of measurements has been conducted on two superconducting radio-frequency cavity pairs, installed in cryomodules and routinely operated in the Continuous Electron Beam Accelerator Facility, in order to study the RF-vacuum interaction during an RF fault. These arc-related fault rates increase with increasing machine energy, contribute to system downtime and directly affect the accelerator?s availability. For this study, the fundamental power coupler waveguides have been instrumented with vacuum gauges, additional arc detectors, additional infrared sensors and temperature sensors in order to measure the system response during both steady-state operations and RF fault conditions. Residual gas analyzers have been installed on the waveguide vacuum manifolds to monitor the gas species present during cooldown, RF processing and operation. Simultaneous measurements of the signals are presented, a comparison with analysis is shown and results are discussed. The goal of this study is to characterize the RF-vacuum interaction during normal operations. With a better understanding of the installed system response, methods for reducing the fault rate may be devised, ultimately leading to improvements in availability.  
 
MOPLT159 RF Techniques for Improved Luminosity at RHIC gun, vacuum, quadrupole, beamloading 905
 
  • J.M. Brennan, M. Blaskiewicz, J. Butler, J. DeLong, W. Fischer, T. Hayes
    BNL, Upton, Long Island, New York
  The Relativistic Heavy Ion Collider has improved its luminosity performance significantly in the course of the first three physics runs. A number of special techniques for the operation of the rf systems have been developed to facilitate these improvements. Herein we describe these techniques, which include: an ultra low-noise rf source for the 197 MHz storage cavities; synchronization of the two rings during acceleration (including crossing the transition energy) to avoid spurious collisions on the ramp, which modulate the beam-beam tune shift; a frequency shift switch-on technique for transferring bunches from the acceleration to the storage rf systems; installation of dedicated 200 MHz cavities to provide longitudinal Landau damping on the ramp, and automated corrections to longitudinal injection parameters to minimize emittance growth.  
 
MOPLT162 Continuous Abort Gap Cleaning at RHIC gun, vacuum, quadrupole, beamloading 908
 
  • K.A. Drees, R.P. Fliller III, W. Fu, R. Michnoff
    BNL, Upton, Long Island, New York
  Since the RHIC Au-Au run in the year 2001 the 200 MHz cavity system was used at storage and a 28 MHz system during injection and acceleration.The rebucketing procedure potentially causes a higher debunching rate of heavy ion beams in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam can easily account for more than 30% of the total beam intensity. This effect is even stronger with the achieved high intensities of the RHIC run 2004. A beam abort at the presence of a lot of debunched beam bears the risk of magnet quenching and experimental detector damage due to uncontrolled beam losses. Thus it is desirable to avoid any accumulation of debunched beam from the beginning of each store, in particular to anticipate cases of unscheduled beam aborts due to a system failure. A combination of a fast transverse kicker and the new 2-stage copper collimator system is used to clean the abort gap continuously throughout the store with a repetition rate of 1 Hz. This report gives an overview of the new gap cleaning procedure and the achieved performance.  
 
MOPLT164 Bunch Patterns and Pressure Rise in RHIC gun, vacuum, quadrupole, beamloading 914
 
  • W. Fischer, U. Iriso
    BNL, Upton, Long Island, New York
  The RHIC luminosity is limited by pressure rises with high intensity beams. At injection, the dominating cause for the pressure rise was shown to be electron clouds. We discuss the distributions of bunches along the circumference that minimize the electron cloud effect in RHIC. Experimental data are compared with simulation results, and experiences at the B-factories.  
 
MOPLT171 A Pratical Demonstration of the CRFQ Storage Ring gun, electron, vacuum, beamloading 926
 
  • A. Ruggiero
    BNL, Upton, Long Island, New York
  • L. Campajola, V.G. Vaccaro
    Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli
  • D. Davino
    Universita' degli Studi del Sannio, Benevento
  • M.R. Masullo
    INFN-Napoli, Napoli
  The Circular Radiofrequency Quadrupole (CRFQ) is a new concept of a storage and accelerator ring for intense beams of light and heavy ions, protons and electrons. It is basically a Linear Radio-Frequency Quadrupole completely bent on a circle. The advantages are expected to be equivalent to those of a Linear RFQ, namely higher beam intensity and smaller beam dimensions. Moreover, it is a more compact device when compared to conventional accelerators. A collaboration was created between Brookhaven National Laboratory, the University of Naples, the University of Sannio, and the INFN-Section of Naples (Italy) for the purpose of developing a proof of principle (PoP) of the CRFQ. During the initial stage the main goal is the demonstration of the curvature effect of the quadrupolar RFQ field. At that purpose, the project is actually conceived of three phases: (i) develop an adequate 30 keV proton source, (ii) design, manufacture and test a linear RFQ section, and (iii) design, manufacture and test a curved RFQ section, both operating at 200 MHz. The linear section acts as a matching with the ion source at one end, and the curved section at the other. The paper discusses mechanical and RF considerations during the design and experiment. The final goal of the collaboration is eventually to build enough curved sections to complete the storage ring where to demonstrate storage of 30 keV protons over long periods of time.  
 
MOPLT172 Quest for a New Working Point in RHIC gun, electron, vacuum, beamloading 929
 
  • R. Tomas, M. Bai, W. Fischer, V. Ptitsyn, T. Roser, T. Satogata
    BNL, Upton, Long Island, New York
  The beam-beam interaction is a limiting factor in RHIC's performance, particularly in proton operation. Changing the working point is a strategy to minimize the beam-beam effect and improve the performance of the machine. Experiments at injection energy and simulations have been performed for a set of working points in order to determine what are the best candidates.  
 
MOPLT174 Electron Acceleration for e-RHIC with the Non-scaling FFAG gun, vacuum, beamloading, hadron 932
 
  • D. Trbojevic, M. Blaskiewicz, E.D. Courant, J. Kewisch, T. Roser, A. Ruggiero, N. Tsoupas
    BNL, Upton, Long Island, New York
  A non-scaling FFAG lattice design to accelerate electrons from 3.2 to 10 GeV is described. This is one of the possible solutions for the future electron-ion collider (eRHIC) at Relativistic Heavy Ion Collier (RHIC) at Brookhaven National Laboratory (BNL). This e-RHIC proposal requires acceleration of the low emittance electrons up to energy of 10 GeV. To reduce a high cost of the full energy super-conducting linear accelerator an alternative approach with the FFAG is considered. The report describes the 1277 meters circumference non-scaling FFAG ring. The Courant-Snyder functions, orbit offsets, momentum compaction, and path length dependences on momentum during acceleration are presented.  
 
MOPLT175 A Method to Measure the Focusing Properties (R_Matrix) of a Magnet gun, vacuum, focusing, beamloading 935
 
  • N. Tsoupas, L. Ahrens, K.A. Brown, D. Gassner, J. Glenn, Y.Y. Lee, T. Roser, P. Thieberger, J. Wei
    BNL, Upton, Long Island, New York
  We discuss a method that may be used to measure the focusing properties of a magnet. This method may prove valuable when applied to non-conventional magnets that deviate from the usual dipole magnets or other multipole magnets which are commonly used in a synchrotron. In this category of non-conventional magnets, fall special magnets, which come under the name Snakes. Such magnets are being used in synchrotron accelerators[*,**] to introduce artificial spin resonances to help overcome the intrinsic and/or imperfection spin resonances. This method of measuring the focusing properties of a magnet requires the use of low energy and high rigidity heavy-ions which may be obtained from the BNL Tandem accelerator.In brief the method consists on, injecting low emittance beamlets of lightly stripped heavy ions into a magnet and measuring the coordinates, of these narrowbeamlets, at the entrance and exit of the magnet.From the measurement of these coordinates of the narrowbeamlets we can deduce information on the R matrix and higher order matrix elements that define the focusing properties of the magnet.

* T. Roser, AIP Conf. Proc. 187 (1988) 1221** H.Huang, et. al. Phys. Rev. Lett. 73 (1994) 2982

 
 
TUYBCH01 Design Criteria and Technology Challenges for the Undulators of the Future gun, radiation, focusing, laser 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
 
TUYBCH02 Technological Challenges for High Brightness Photo-injectors gun, radiation, focusing, laser 64
 
  • G. Suberlucq
    CERN, Geneva
  Many applications, from linear colliders to free-electron lasers, passing through light sources and many other electron sources, require high brightness electron beams, usually produced by photo-injectors. Because certain parameters of these applications differ by several orders of magnitude, various solutions were implemented for the design and construction of the three main parts of the photo-injectors: lasers, photocathodes and guns. This paper summarizes the different requirements, how they lead to technological challenges and how R&D programs try to overcome these challenges. Some examples of state-of-the-art parts are presented.  
Video of talk
Transparencies
 
WEPKF017 The 5 T Superconducting Undulator for the LHC Synchrotron Radiation Profile Monitor focusing, kicker, bunching, alignment 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.  
 
WEPKF018 Beam-loss Induced Pressure Rise of LHC Collimator Materials Irradiated with 158 GeV/u In49+ Ions at the CERN SPS focusing, ion, kicker, bunching 1633
 
  • E. Mahner, I. Efthymiopoulos, J. Hansen, E. Page, H. Vincke
    CERN, Geneva
  During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 104 to 107 molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measurement of heavy-ion induced molecular desorption in the GeV/u energy range is important for LHC ion operation. In 2003, a desorption experiment was installed at the SPS to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316 LN stainless steel, were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental set-up, the results of the pressure rise measurements are presented, and the derived desorption yields are compared with data from other experiments.  
 
WEPKF019 Magnetic Measurement Systems for the LHC Dipole Assembly Firms focusing, ion, kicker, bunching 1636
 
  • H. Reymond, J. Billan, J. Garcia Perez, D. Giloteaux, A. Raimondo, V. Remondino, A. Rijllart
    CERN, Geneva
  The LHC lattice superconducting dipole magnets are actually under construction in three European industries. Due to the extremely high magnet performance required for the LHC, these magnets have to be built with high accuracy during all the steps of their assembling. In order to detect defects in the earliest production phases and to ensure the quality of the magnetic field as specified by the CERN contracts, dedicated measurement benches have been built and installed in each industry to validate the magnetic field quality at two important production stages. This paper describes the initial requirements and the implementation of the magnetic measurement systems. Details on the technical solutions, the present status and measurement results are presented.  
 
WEPKF020 The Design of the Special Magnets for PIMMS/TERA focusing, kicker, bunching, vacuum 1639
 
  • L. Sermeus, J. Borburgh, T. Fowler, M. Hourican, K.D. Metzmacher
    CERN, Geneva
  • M. Crescenti
    TERA, Novara
  In the framework of a collaboration agreement with the TERA Foundation CERN provided the design, drawings and engineering specifications for 2 kickers, 1 chopper and 3 bumper magnets as well as 3 magnetic and 2 electrostatic septa, power supplies for the electrostatic septa, kickers and bumpers including control electronics for the PIMMS/TERA proton and carbon ion medical synchrotron. The first application will be in the Italian National Centre for Hadron Therapy, to be constructed in Pavia. The main features of the devices are described along with the strategic design choices, directed by the demand for very high reliability and minimum maintenance.  
 
WEPKF021 Non-destructive Testing of Bus-bar Joints Powering LHC Superconducting Magnets, by Using Gamma Sources focusing, kicker, bunching, vacuum 1642
 
  • B. Skoczen
    CERN, Geneva
  • J. Kulka
    AGH, Cracow
  The main LHC superconducting magnets (dipoles and quadrupoles) are powered by using Rutherford type cables, stabilized electrically and thermally with copper profiles. The portions of cables are connected to each other by a soft soldering technique (Sn96Ag4) with the overlapping length corresponding to one pitch of the superconducting strands. The splice constitutes a ?composite? structure with the interchanging layers of Sn96Ag4 and NbTi superconductor, located inside a Cu cage. In order to assure a high level of reliability (failure probability not exceeding 10-8) for some 10000 connections in the LHC, a non-destructive technique of checking the quantity of solder in the joint is planned to be implemented. The technique is based on a gamma ray source (241_Am) and the detection is position-sensitive in the transmission mode. 5 scintillating detectors of gamma rays are used and their accumulated length corresponds to the length of the radioactive source (120 mm). The method can be used in-situ, the equipment being optimized and portable, with implementation of direct on-line operation mode. The relevant criteria of acceptance of the splices have been defined. The first results of application of this technique will be shown.  
 
WEPKF022 Electro-mechanical Aspects of the Interconnection of the LHC Superconducting Corrector Magnets kicker, bunching, vacuum, alignment 1645
 
  • J.-P.G. Tock, D. Bozzini, F. Laurent, S. Russenschuck, B. Skoczen
    CERN, Geneva
  In addition to the main 1232 bending dipoles and 474 focusing and defocusing quadrupoles, more than 6800 superconducting corrector magnets are included in the LHC machine. They are housed in the superfluid helium enclosures of the main cryomagnets. Among them, the closed orbit correctors (sextupole and octupole) are integrated in the main quadrupole helium vessel and they are powered via an externally routed cryogenic line (line N). During the assembly, these corrector magnets have to be connected according to a complex electrical scheme based on the optical requirements of the LHC machine. Along the 27-km long LHC machine, 440 interconnection boxes are installed and will allow the powering of the correctors by means of a 42-wires auxiliary bus-bar cable, of which the corresponding wires have to be routed to the SSS from the interconnection box. Stringent requirements in terms of volume, mechanical resistance, electrical conductance and insulation, reliability, and respect of the electrical schematics apply during the assembly and splicing of the junctions inside the line-N box. The activities and their sequence, aiming at ensuring the fulfilment of these requirements are presented. The planned activities (assembly, ultrasonic welding, general and electrical inspection, and electrical qualification) and the interactions between the various intervening teams are described.  
 
WEPKF024 The Geometry of the LHC Main Dipole kicker, bunching, vacuum, beamloading 1648
 
  • E.Y. Wildner, J. Beauquis, G. Gubello, M. La China, W. Scandale
    CERN, Geneva
  The 15 m long main dipole of the Large Hadron Collider has a curvature following the beam trajectory with the aim to minimize the necessary coil aperture. To avoid feed-down effects and mechanical aperture restrictions strong constraints have to be imposed on the construction of the magnet in terms of tolerances and stability of the cold mass during transport, cryostating, cold tests and installation in the LHC tunnel. In this paper we show the behaviour of the shape of the magnet using available measurements taken at different stages of construction and assembly. In particular we discuss the evolution of the sagitta and the positioning of the corrector magnets that are used to compensate the multipole field errors. We propose alignment procedures to be used in case magnets are out of tolerance after transport and cold tests. The twist of the magnet and its relation to the field angle will also be discussed.  
 
WEPKF025 Experience with the Hydrostatic Levelling System of the SLS kicker, bunching, vacuum, beamloading 1651
 
  • F.Q. Wei, L. Rivkin, A. Wrulich
    PSI, Villigen
  The Hydrostatic Levelling System (HLS) of the SLS was installed and commissioned in year 2000. It is a measurement system for monitoring the vertical positions of the SLS storage ring girders. It is integrated in the concept of dynamic alignment. The HLS was modified and re-calibrated in 2002. Since January 2003 the system has collected approximately 2 million measurements. The analysis of the data shows that displacement of the SLS storage ring foundation and the girder support was in the range of 0.15 mm in year 2003. The long term HLS stability was significantly improved. The short term precision of the HLS is in the micrometer range. The experience gained on the HLS is presented.  
 
WEPKF026 Kicker Pulser with High Stability for the BESSY FEL kicker, bunching, vacuum, beamloading 1654
 
  • J. Feikes, O. Dressler, J. Kuszynski
    BESSY GmbH, Berlin
  In the BESSY FEL design a kicker system is forseen to extract electron bunches from the main LINAC into two FEL beam lines, beside the straigth main beamline. Sine half wave pulsers with a repetion rate of up to 1 kHz and modest pulse currents of 120A will be used. To receive the maximum FEL gain, it is crucial, that the extracted bunches enter well centered into the undulators. Hence, the extraction demands for very high short-term stability of the magnetic field (shot to shot). A kicker pulse amplitude with a relative amplitude jitter smaller than 5* 10-5 would be tolerable ?more than one order smaller than the jitter of conventional BESSY II kicker systems in use. A new highly stable semiconductor based kicker pulser prototype was designed, built and tested at BESSY. It was shown that the stability of the pulse current fulfills the FEL requirements. The pulser design, its layout and the corresponding pulse current jitter measurements are presented.  
 
WEPKF027 R&D Vacuum Issues of the Future GSI Accelerator Facilities ion, kicker, bunching, beamloading 1657
 
  • H.R. Sprenger, M.C. Bellachioma, M. Bender, H. Kollmus, A. Krämer, J. Kurdal, P.J. Spiller
    GSI, Darmstadt
  The new GSI accelerator facilities are planned to deliver heavy ion beams of increased energy and highest intensity. Whereas the energy is planned to be increased roughly by a factor of 10, the ion beam intensities are planned to be enlarged by three orders of magnitude. To achieve highest beam intensities, medium charged heavy ions (e.g. U28+) are accelerated. Since the ionization cross sections for these ions are comparably high, a UHV-accelerator system with a base pressure in the low 10-12mbar regime is required, even under the influence of ion beam loss induced desorption processes. An intensive program was started to upgrade the UHV system of the existing synchrotron SIS18 (bakeable) and to design and lay out the UHV systems of the future synchrotron SIS100 and SIS300 (mainly cryogenic). The strategy of this program includes basic research on the physics of the ion induced desorption effects as well as technical developments, design and prototyping on bakeable UHV components (vacuum chambers, diagnostics, bakeout-control, pumping speed), collimator for controlled ion beam loss, NEG coating and cryogenic vacuum components.  
 
WEPKF028 High Charge Transfer Operation of Light Trigged Thrystor Crowbars ion, kicker, bunching, beamloading 1660
 
  • W. Merz
    DESY, Hamburg
  High power klystrons are protected by the application of crowbar switches. The closing switch approach is most commonly used. It is characterized by establishing a short circuit path to bypass the klystron fault current. During short circuit operation the crowbar switch must be capable to carry both puls current of the filter capacitor and follow through current of the high voltage dc power supply. Depending on the main circuit parameters both the capacitor charge and the follow through charge can achieve significant amounts. The application of line controlled and uncontrolled hvdc power converters requires special attention regarding the follow through current charge transfer. This paper presents first practical results of series connected Light Triggered Thyristors (LTT) operating as closing crowbar switches. Measured data are discussed, which have been obtained from the DESY-II installation operating with thyristor controllers and the PETRA installation operating with uncontrolled rectifiers. Beside the puls operation the follow through current capability of the crowbar is pointed out.  
 
WEPKF029 The Vacuum System of the Australian Synchrotron vacuum, kicker, bunching, beamloading 1663
 
  • E. Huttel
    FZK-ISS-ANKA, Karlsruhe
  • B. Barg, A. Jackson, B. Mountford
    ASP, Melbourne
  A 3 GeV Synchrotron Radiation Source is being built in Melbourne, Australia. The storage ring has a circumference of 216 m and has a 14 fold DBA structure. The vacuum chambers of the storage ring will be made from stainless steel. They consist of a beam chamber (width 70, height 32mm ) connected to an ante chamber, where lumped absorbers and lumped ion pumps are installed. No distributed absorber and pumps are foreseen. The nominal pumping speed of the complete ring is 31 000 l/s. The vacuum chamber of an achromat will be baked ex situ and installed under vacuum. The design of the chamber, the pump configuration and the expected vacuum behaviour will be presented.  
 
WEPKF030 The Storage Ring Magnets of the Australian Synchrotron vacuum, kicker, bunching, beamloading 1666
 
  • E. Huttel
    FZK-ISS-ANKA, Karlsruhe
  • B. Barg, A. Jackson, G. LeBlanc
    ASP, Melbourne
  • J. Tanabe
    SLAC, Menlo Park, California
  A 3 GeV Synchrotron Radiation Source is being built up in Melbourne, Australia. The storage ring has a circumference of 216 m and has a 14 fold DBA structure. For the storage ring the following magnets are required: 28 gradient dipoles, with B = 1.3 T, B’ = 3.35 T/m, 56 quadrupoles with a gradient of B’ = 18 T/m, 28 quadrupoles with a gradient of 9 T/m, 56 sextupoles with d2B/dr2 = 320 T/m2 and 42 with 150 T/m2. The design of pole faces was done by scaling the SPEAR III pole face to the required gap and bore of the ASP storage ring magnets. The sextupoles will be equipped with coils for horizontal and vertical correction and for a skew quadrupole. The design of the magnets and the calculated magnetic properties will be presented.  
 
WEPKF031 Magnetic Field Correction of the Bending Magnets of the 1.5 GeV HDSM vacuum, kicker, bunching, beamloading 1669
 
  • F. Hagenbuck, P. Jennewein, K.-H. Kaiser
    IKP, Mainz
  Beam dynamics of the Harmonic Double Sided Microtron (HDSM), the fourth stage of MAMI, require a very precise magnetic field in the inhomogeneous bending magnets. By measuring the vertical field component By in and on both sides of the midplane, the complete set of field components Bx, By, Bz was determined in the whole gap. Starting from this the asymmetric pole surface current distribution necessary to correct both symmetric and antisymmetric field errors was calculated. However, tracking calculations showed that the influence of skewed field components on the beam deflection are negligible, so that symmetric field corrections are sufficient. Nevertheless, in order to demonstrate the functioning, a set of asymmetric correction coils was built and successfully tested. The symmetric coils are designed to reduce field errors below 2*10-4. Deflection errors in the fringe field region near the magnet corners, which cannot be corrected by surface currents, will be compensated by vertical iron shims in combination with small dipoles on each beam pipe.  
 
WEPKF032 A General Method for 2d Magnet Pole Design vacuum, kicker, bunching, beamloading 1672
 
  • Z. Martí, J. Campmany, M. Traveria
    LLS, Bellaterra (Cerdanyola del Vallès)
  Accurate conventional combined magnets working in saturation are currently required to fulfil the increasing demands on low emittance accelerators with long straight sections required by the newest Synchrotron Light Sources. This fact yields stringent requirements on pole profile design, manufacture and characterization. The aim of this poster is to present a general method for designing two-dimensional pole profiles. To this end, we have set up a procedure with which to select an optimum pole profile in 2D without the constraint of relying on a set of initial assumptions, not only a particular set of initial parameters but even a particular pole profile model. Moreover, we have developed a group of codes that can be compiled and run on MS-DOS or UNIX which use POISSON or OPERA-2d codes. This procedure also includes the evaluation of the sensitivity of the final pole profile to geometrical and current intensity errors for tolerance estimation, a big requirement in this context. In order to test the feasibility of this method, we have applied it to the case of the 1.2 T combined magnet of the new synchrotron to be built nearby Barcelona.  
 
THYLH01 Beam Diagnostics at the VUV-FEL Facility electron, injection, radiation, wakefield 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
 
THOBLH01 Recent Improvement of Slow-extraction at HIMAC Synchrotron electron, extraction, injection, radiation 267
 
  • T. Furukawa, T. Furukawa, T.H. Uesugi
    Chiba University, Graduate School of Science and Technology, Chiba
  • T. Fujimoto, M. Kanazawa, K. Noda, S. Shibuya, E. Takada, S. Yamada
    NIRS, Chiba-shi
  • T. Naruse
    Seikei University, Graduate School of Engineering, Tokyo
  At HIMAC synchrotron, two kinds of slow-extraction method have been developed and utilized: third-order resonant slow-extraction and that with RF-knockout, not only for ion therapy but also for physics and biological experiments. Thus, the improvements of the extracted beam quality have also been carried out in both methods. One of the improvements is the global spill control. The global spill is improved owing to analytical approach in both methods. Cooperating with the feedback system, the flat spill is easily obtained without gain control of the feedback during the extraction. On the other hand, the effect of longitudinal motion for the bunched beam was studied to suppress the frequency component of the synchrotron oscillation in the spill ripple. Further, the transport of the extracted beam is readjusted for controlling the beam size. In this paper, recent improvement of slow-extraction at HIMAC is presented.  
Video of talk
Transparencies
 
THOBLH02 Ultrafast Compton Scattering X-Ray Source Development at LLNL extraction, injection, radiation, wakefield 270
 
  • F.V. Hartemann, S. Anderson, C.P.J. Barty, S.M. Betts, R. Booth, J. Brown, K. Crane, R.R. Cross, D.N. Fittinghoff, D. Gibson, E.P. Hartouni, J. Kuba, G.P. Le Sage, D.R. Slaughter, P.T. Springer, A. Tremaine, A.J. Wootton
    LLNL, Livermore, California
  • J. Rosenzweig
    UCLA, Los Angeles, California
  The LLNL PLEIADES (Picosecond Laser-Electron Inter-Action for the Dynamical Evaluation of Structures) facility is now operating between 30 and 80 keV, and produces > 5 x 106 photons per shot at 10 Hz. This important milestone offers a new opportunity to develop laser-driven, compact, tunable x-ray sources for critical applications such as NIF diagnostics, time-resolved material studies, and advanced biomedical imaging. Initial x-rays were captured with a CCD using a CsI scintillator; the photon energy was measured at approximately 70 keV, and the observed spectral and angular distributions found to agree very well with three-dimensional codes. The electron beam was focused to 30 um rms, at 54 MeV, with 250 pC of charge, a relative energy spread of 0.2%, and a normalized emittance of 10 mm.mrad. Optimization of the x-ray dose is currently underway, with the goal of reaching 107 photons per shot and a peak brightness approaching 1017 photons/mm2/mrad2/s/0.1%bandwidth. High-Z K-edge radiographs have been demonstrated, as well as diffraction using highly-ordered pyrolytic graphite crystals. Nonlinear scattering experiments, using a tightly focused laser spot will also be discussed, as well as plans to develop a source capable of reaching 1% conversion efficiency from the electron beam kinetic energy into x-rays, and ultrafast diffraction experiments.  
Video of talk
Transparencies
 
THOBLH03 BESSY II Operated as a Primary Source Standard extraction, injection, wakefield, laser 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
 
THPKF001 Status of 3 GeV CANDLE Synchrotron Light Facility Project extraction, injection, wakefield, laser 2251
 
  • V.M. Tsakanov, M. Aghasyan, G. Amatuni, V.S. Avagyan, A. Grigoryan, B. Grigoryan, M. Ivanyan, V. Jalalyan, D. Kalantaryan, V.G. Khachatryan, E.M. Laziev, Y.L. Martirosyan, R.H. Mikaelyan, S. Minasyan, K.N. Sanosyan, S. Tatikian, S. Tunyan, A. Vardanyan
    CANDLE, Yerevan
  CANDLE- Center for the Advancement of Natural Discoveries using Light Emission – is a 3 GeV third generation synchrotron light facility project in Republic of Armenia. The presentation includes the main considerations that underlie the Conceptual Design Report of the project and the progress made after the last EPAC conference. An overview of machine and beam physics study, the prototype and laboratory development is given.  
 
THPKF002 Linac RF Control System for CANDLE. Design and Simulation extraction, injection, linac, wakefield 2254
 
  • A. Vardanyan, G. Amatuni
    CANDLE, Yerevan
  The design and constructional features of the control system for 500 MHz and 3 GHz RF system of CANDLE linac are presented. The linac includes an electron gun that is modulated by 500 MHz generator to produce 1 ns electron bunches, 500 MHz and 3 GHz bunchers, pre-accelerating cavity and the main accelerating section at 3 GHz. An important feature of the presented control system is a high level synchronization of amplitude-phase characteristics of the sub-systems that provide the required energy-space characteristics of the accelerated beam. This puts strict requirements on RF frequency, amplitude and phase stabilization. A digital feedback system has been adopted to provide flexibility in the control algorithms. The main feature is a 9 MHz sampling rate for the cavity signals and digital I/Q detection. The design was performed using the RF analyze tool, based on MATLAB SIMULINK, which allows the simulation and analyzes of the field regulation quality. The simulation results for CANDLE Linac RF system, based on the output parameters of electron beam are given.  
 
THPKF004 The Australian Synchrotron Project - Update extraction, injection, linac, wakefield 2257
 
  • A. Jackson
    ASP, Melbourne
  The Australian Synchrotron - a 3rd generation synchrotron light facility based on a 3-GeV electron storage ring - is under construction at a site adjacent to Monash University in the Metropolitan District of Melbourne. Site preparation started in September 2003 and project completion is scheduled for March 2007. In this paper we present an overview of the facility and discuss progress to date in meeting this very agressive schedule.  
 
THPKF005 The Australian Synchrotron Project Storage Ring and Injection System Overview extraction, injection, linac, wakefield 2260
 
  • G. LeBlanc, M.J. Boland, Y.E. Tan
    ASP, Melbourne
  This paper describes the Australian Synchrotron storage ring. The storage ring is a 3 GeV machine with 14 cells and a circumference of 216 m. The unit cell is based on a Double Bend Achromat (DBA) structure. The design of the magnet lattice and the results of simulations pertaining to the storage ring performance are presented.  
 
THPKF006 Lifetime Studies in the LNLS Electron Storage Ring extraction, injection, linac, wakefield 2263
 
  • N.P. Abreu, N.P. Abreu
    UNICAMP, Campinas, São Paulo
  • P.F. Tavares
    LNLS, Campinas
  In this paper we present a set of measurements performed at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. We measured the beam lifetime as a function of: current per bunch, gap voltage and position of horizontal and vertical scrapers. Those measurements helped us to determine the contribution of various particle loss mechanisms (Touschek, elastic and inelastic scattering and quantum fluctuations) to the lifetime of the beam. Comparison with theory is also presented as well as an interpretation of each effect.  
 
THPKF007 Canadian Light Source Status and Commissioning Results extraction, linac, wakefield, laser 2266
 
  • L. Dallin, R. Berg, J.C. Bergstrom, X. Shen, R.M. Silzer, J.M. Vogt, M.S. de Jong
    CLS, Saskatoon, Saskatchewan
  The storage ring for the Canadian Light Source (CLS) was completed in August 2003. By January 2004, after about shifts of commissioning beam currents of up to 25 mA with 0.7 hr lifetimes were achieved. Injection times for 25 mA are about 4 minutes. Commissioning activities include global orbit correction, measurement of machine parameters and beam-based diagnostices. Features of the CLS are a compact lattice (170 m) for a 2.9 GeV storage ring, high performance magnets and a superconducting RF cavity. By July, when beamlines become operational, currents up to 100 mA with 4 hour lifetimes are expected.  
 
THPKF008 Injection System for the Canadian Light Source injection, extraction, wakefield, laser 2269
 
  • R.M. Silzer, R. Berg, J.C. Bergstrom, L. Dallin, X. Shen, J.M. Vogt
    CLS, Saskatoon, Saskatchewan
  The full energy injection system for the Canadian Light Source is made up of a 250 MeV linac, a low energy transfer line, a 2.9 GeV booster synchrotron and a high energy transfer line. The system has routinely provided up to 25 mA peak current in a 132 ns pulse train to the CLS storage ring injection point since September 2003. By January, 2004, injection efficiencies up to 10% have been acheived and stored currents up to 25 mA were accumulated in less than 4 minutes. The injection timing system allows a variety of fill patterns. By July, 2004, injection rates of up to 2 mA per second should be possible providing a fill time of under one minute for a 100 mA stored beam.  
 
THPKF009 Orbit Control for the Canadian Light Source injection, extraction, wakefield, laser 2272
 
  • R. Berg, L. Dallin, J.M. Vogt
    CLS, Saskatoon, Saskatchewan
  The orbit control system for the Canadian Light Source storage ring is design to provide both static global orbit correction and active correction up to 100 Hz. The system is made up of 48 button monitors (X and Y), 24 fast correcter magnets (X and Y), and 24 slow correction coils in sextupole magnets (X and Y). To date the system has been use to apply static corrections the to CLS storage ring. While some works remains on the horizontal correction, the vertical orbit has been corrected to an RMS value of less tha 0.75 mm. Future corrections may be augmented by some beam-based magnet re-alignment. The orbit correction system is run on a MATLAB(R) operating system. Singular value decompostion (svd) was used extensively to reduce initial gross mis-alignments.  
 
THPKF011 Vibration Measurements at the Swiss Light Source (SLS) injection, extraction, wakefield, laser 2275
 
  • S. Redaelli, R.W. Assmann, W. Coosemans
    CERN, Geneva
  • M. Böge, M. Dehler, L. Rivkin
    PSI, Villigen
  Vibration measurements have been carried out at the Swiss Light Source (SLS) site as part of a collaboration between the Paul Scherrer Institute (PSI) and the European Organization for Nuclear Research (CERN). The vibration level of the SLS floor and of some lattice elements of the SLS ring have been monitored under various experimental conditions. In particular, vibration spectra of lattice quadrupoles have been measured with a circulating beam and compared with the spectra of transverse beam positions, as measured with beam position monitors. This paper summarizes the results.  
 
THPKF012 Operation of the Swiss Light Source: Top-up for Highest Performance injection, extraction, wakefield, laser 2278
 
  • A. Lüdeke
    PSI, Villigen
  The Swiss Light Source (SLS) is now in its third year of user operation. Right from the beginning Top-up has been the standard mode of operation. Operation at a fixed beam current makes many applications easier to implement and allows to push several systems to higher performance. It enabled us to reach an excellent orbit stability and reproducibility and it made our users less sensitive to shortened beam lifetimes. We succeeded to satisfy the high demands on the availability of the injector system and our flexible timing system allows for a parallel usage of the Linac for experiments during Top-up operation. The impact of Top-up operation on the overall performance of the SLS is documented in this paper.  
 
THPKF013 Terahertz Diagnostics for the Femtosecond X-ray Source at BESSY injection, wakefield, beamloading, lattice 2281
 
  • 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

 
 
THPKF066 Conception of X-ray Source Based on Compact Wakefield Undulator target, vacuum, gun, simulation 2412
 
  • 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.  
 
THPKF067 Progress of the DIAMOND Storage Ring and Injector Design. target, vacuum, gun, simulation 2415
 
  • S.L. Smith, D.J. Holder, J.K. Jones, J.A. Varley, N.G. Wyles
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Bartolini, I.P.S. Martin, B. Singh
    Diamond, Oxfordshire
  DIAMOND is a state of the art 3 GeV synchrotron light source that will be available to users in 2007. Considerable further progress has been made on the accelerator physics design of the storage ring, booster and other associated injector systems. Detailed analysis of injection processes, lifetime, coupling, instabilities, feedback systems and dynamic aperture have been undertaken driven by the procurement activity and the desire to fully understand all aspects of the accelerator's performance.  
 
THPLT013 Simulation of Multi-bunch Multi-turn Instabilities in High Energy Proton Rings: Algorithms and Results antiproton, laser, target, lattice 2487
 
  • A. Koschik
    CERN, Geneva
  A simulation code to study collective effects in multi-bunch proton machines has been developed and applied to the CERN SPS and LHC. The 3D simulation program allows the exploration of long-range effects due to resistive-wall and HOMs in circular, elliptic and rectangular vacuum chambers also for uneven filling schemes. The code has been benchmarked with measurements in the SPS. Results obtained for LHC, including beam stability and emittance growth, are presented and discussed.  
 
THPLT014 Coupler Structures for the LHC Beam-pipe Waveguide Mode Reflectometer antiproton, laser, target, lattice 2490
 
  • T. Kroyer
    TU Vienna, Vienna
  • F. Caspers
    CERN, Geneva
  The LHC reflectometer will be used to detect and localize obstacles and other kinds of discontinuities in the LHC beam screen. An important part of this device is the RF coupler element, which provides the interface between the circular beam screen and the measurement equipment. Two different scenarios of operation are considered. The first option consists in carrying out measurements during assembly by directly branching a coupler to the end of the beam screen. The other one is a permanent installation to be used in situ requiring a different kind of coupler to keep the aperture free. The goal is to achieve a reasonably well-matched spurious mode-free excitation over a 25% bandwidth for the TM01 and the T·1011 mode, respectively. The fulfillment of the required features is severely complicated by space and material restrictions arising mainly from vacuum and installation constraints.  
 
THPLT015 Accuracy of Profile Monitors and LHC Emittance Measurements antiproton, laser, target, lattice 2493
 
  • F. Roncarolo, G. Arduini, B. Dehning, G. Ferioli, J. Koopman, D. Kramer
    CERN, Geneva
  The monitoring and controlling of the beam transverse emittance is essential to allow high luminosity performances in a collider operation. The profile monitors in the LHC injection chain are exploited to determine their precision. A fit strategy was developed to reduce the fitting procedure error and make it negligible compared to instrumentation errors. The method proved to be robust against non-Gaussian tails and can estimate the fraction of non-Gaussian distributed beam intensity. The procedure was applied to the 2003 SPS Wire Scanner measurements with different kind of LHC type beams. The reproducibility of the six available monitors was determined by choosing one as a reference and making synchronized measurements. Several instrumental errors were discovered and corrected to the one per cent level. The demanding small LHC transverse emittances were determined under different beam conditions in terms of intensity, bunch spacing and length in the PS Booster, PS and SPS.  
 
THPLT022 The Generic VME PMC Carrier Board: A Common Digital Hardware Platform for Beam Diagnostics and Feedbacks at PSI antiproton, gun, target, lattice 2514
 
  • B. Keil, C. Buehler, P.-A. Duperrex, U. Greuter, R. Kramert, P. Pollet, V. Schlott, N. Schlumpf, P. Spuhler
    PSI, Villigen
  Rapid progress in digital electronics allows digitization of monitor signals at a very early stage of the signal processing chain, providing optimum performance and maximum flexibility for today's accelerator instrumentation. While the analog front-ends of such systems are usually specific for each monitor type, the subsequent digital part of the processing chain can be unified for many different measurement tasks. The "VME generic PMC Carrier board" (VPC) was developed to achieve this unification at the PSI electron and proton accelerator diagnostics and fast data acquisition and feedback systems. The core of the VME64x board consists of two Virtex2Pro FPGAs with two PowerPCs each, a floating point DSP and RAM. The FPGAs can acquire and process measurement data from the VMEbus P0/P2 connectors or from two application-dependent PMC mezzanine modules. Two 2 GBaud fibre optics transceivers may also be used to aquire or distribute measurement data. Envisaged applications include digital beam position (DBPM) and current monitors for proton beams, data processing for a muon decay experiment, and general beam diagnostics as well as global feedbacks at SLS accelerators and beamlines.  
 
THPLT025 Using Visible Synchrotron Radiation at the SLS Diagnostics Beamline antiproton, gun, target, lattice 2523
 
  • 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.  
 
THPLT044 Measurement of the Transverse Coherence of the TTF Free Electron Laser antiproton, positron, synchrotron, radiation 2577
 
  • 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.  
 
THPLT045 A more Accurate Approach to Calculating Proton Bunch Evolution under Influence of Intra-beam Scattering in a Storage Ring. antiproton, positron, synchrotron, radiation 2580
 
  • I.V. Agapov, F.J. Willeke
    DESY, Hamburg
  Some perturbations of discrete nature are known to influence the performance of a proton storage ring, contributing to parasitic background, decay of beam currents and bunch tail buildup. Such are, for example, intra-beam scattering and residual gas scattering .These processes are to a big extent described by existing analytical theory. The latter, employing a large amount of averaging, usually neglects effects arising from system nonlinearity. So, the motion of tail particles in the presence of a sufficiently nonlinear RF voltage under influence of intra-beam scattering strongly deviates from the average across the bunch and the analytical approach seems inadequate for it. To overcome this situation we have developed more accurate numerical methods for calculations of bunch evolution under influence of a rather broad class of jump-like perturbations. Here we present the computational algorithms and their application to assessment of coasting beam and proton background in HERA-p.