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plasma

                            
Paper Title Other Keywords Page
MOPLT088 Experimental Plasma Wake-field Acceleration Project at the VEPP-5 Injection Complex background, laser, wiggler, acceleration 740
 
  • A.V. Petrenko, A. Burdakov, A.M. Kudryavtsev, P.V. Logatchev, K.V. Lotov, A.N. Skrinsky
    BINP SB RAS, Novosibirsk
  The project of an experimental facility based on the VEPP-5 injection complex is described. Due to a good quality of electron or positron beams and special beam preparation system, the facility opens several possibilities for studies of the plasma wakefield acceleration: high peak beam currents, arbitrary beam profiles, long term beam-plasma interaction (up to the full driver depletion), and precise beam diagnostics. Various wakefield regimes can be experimentally demonstrated and studied: the efficient blow-out regime with a low energy spread and high acceleration rate (up to several GeV per meter); multibunch regime; long bunch instabilities; beam self-organization in plasma; plasma lens. If successfully realized, this experiment becomes a solid argument for feasibility of a high-energy collider based upon the plasma wakefield acceleration.  
 
MOPLT089 SOS-diode Based Pulser for the Injection System of the Collider VEPP-2000 background, laser, wiggler, acceleration 743
 
  • F.V. Podgorny, B.I. Grishanov, A.S. Kasaev
    BINP SB RAS, Novosibirsk
  We describe high voltage pulsers for supplying of kickers of the collider VEPP-2000 injection system. The high voltage pulse is formed as a result of a sharp break of a high current, accumulated previously in storage elements, by means SOS-diode. Pulse forming lines or inductances could be used as the storage elements. The generators form the quasi-rectangular pulses on the 50-Ohm load. The generator scheme is described also.  
 
MOPLT090 High Pulse and Average Power Low-induction Load background, laser, wiggler, acceleration 746
 
  • F.V. Podgorny, B.I. Grishanov
    BINP SB RAS, Novosibirsk
  A high pulse and average power low-induction load with a built-in divider is described in this report. The load has a nominal resistance of 25 Ohm and is designed to operate with a repetition rate of up to 50 Hz at a pulse duration (FWHM) of 100 ns, a rise/fall time of 50 ns and a pulse amplitude of up to 40 kV. In this mode the dissipated energy is equal to about 8 J per pulse and average power is up to 400 W. The load can be used as an absorbing load and as a block element in high-voltage engineering.  
 
MOPLT091 Accelerator Physics Issues of the VEPP-4M at Low Energy background, laser, wiggler, acceleration 749
 
  • V.V. Smaluk
    BINP SB RAS, Novosibirsk
  The VEPP-4M electron-positron collider is being prepared for a new high-energy physics run in the 1.5 - 2.0 GeV energy range. During the first run (2001-2002), precision mass measurements of the J/psi and psi' mesons using the KEDR detector have been carried out with a record accuracy. To provide high performance, efforts for investigation and further development of the machine have been done. The most important results are described. A record absolute accuracy of energy measurement was achieved using the resonant depolarization method. A possibility to use this method for the absolute energy calibration in tau-lepton mass measurements is studied. For the first time, the Moeller polarimeter based on an internal polarized gas jet target has been developed and successfully used at the VEPP-3 booster storage ring. A system of energy measurement using Compton back-scattering has been put into operation. To increase the machine luminosity, operation with dipole wigglers is studied, and a project of turn-by-turn feedback system to suppress beam instabilities has been started. For beam diagnostics, a multi-anode photomultiplier tube and a white light coronograph were installed. The VEPP-4M operation experience with the longitudinal magnetic field within the KEDR detector is also described.  
 
MOPLT092 Single Mode RF Cavity for VEPP-2000 Storage Ring Based Collider background, laser, wiggler, acceleration 752
 
  • V. Volkov, A. Bushuev, E. Kenjebulatov, I. Koop, A. Kosarev, Ya.G. Kruchkov, S.A. Krutikhin, I. Kuptcov, I. Makarov, N. Mityanina, V. Petrov, E. Rotov, I. Sedlyarov, Y.M. Shatunov
    BINP SB RAS, Novosibirsk
  Accelerating cavity 172 MHz with strong damped higher-order modes (HOM) for VEPP-2000 electron-positron collider have been made in Novosibirsk. Resonance frequences and Q values of cavity HOMs are measured and analysed. Most of HOMs have Q values less than 300. We compare these results with computer calculations of HOM.  
 
MOPLT096 Machine Induced Background in the High Luminosity Experimental Insertion of the LHC Project laser, wiggler, acceleration, vacuum 755
 
  • V. Talanov, I. Azhgirey, I. Baishev
    IHEP Protvino, Protvino, Moscow Region
  • K.M. Potter
    CERN, Geneva
  The methodical approach, developed for the solution of the radiation problems in the LHC project, is used for the estimation of the machine induced background in the high luminosity experimental insertion IR1. The results of the cascade simulations are presented for the cases of the proton losses in the cold and warm parts of the collider. The formation of the machine induced background in the interaction region is discussed.  
 
MOPLT097 Co-sourcing Development of Accelerator Controls laser, wiggler, acceleration, vacuum 758
 
  • K. Zagar, R. Sabjan, I. Verstovsek
    JSI, Ljubljana
  • M. Plesko
    Cosylab, Ljubljana
  Frequently, accelerator facilities make use of products and services offered by the industry. This paper's focus is on such outsourcing of control system hardware and software. Firstly, an attempt is made to explain the facility's motivation for seeking outside help, which is typically due to lack of resources, technology or knowledge. Then, the risks of outsourcing are enumerated. To mitigate them, the industrial partner should have not only the adequate technical expertise, but also a reliable, yet agile management and quality assurance process that meets the facility's expectations, schedule, budget constraints, maintenance and support needs. Finally, Cosylab's business model is presented, designed to provide lasting open-source solutions that help not only a single facility, but the entire community.  
 
MOPLT099 NSC KIPT Accelerator on Nuclear and high Energy Physics wiggler, vacuum, electron, wakefield 761
 
  • I.S. Guk, A. Dovbnya, S.G. Kononenko, A.S. Tarasenko
    NSC/KIPT, Kharkov
  • J.I.M. Botman, M.J. Van der Wiel
    TUE, Eindhoven
  One of the main reasons for the outflow of experts in nuclear physics and adjacent areas of science from Ukraine is the absence of modern accelerating facilities, for conducting research in the present fields of interest worldwide in this area of knowledge. A qualitatively new level of research can be achieved by the construction of a new generation accelerator applying the latest developments in the field of electron beam acceleration, in particular on the basis of superconducting accelerating structures of the TESLA type. Such structures may be used for continuous, polarized electron beams, which is crucial e.g. for thin(?) experiments checking modern theoretical models of interactions of nuclear substance, and for beams with high current and extremely short pulses for research in free electron laser and neutron physics. Such a facility will create an opportunity for carrying out research representing the interest of scientists from other countries, which will promote the integration of Ukrainian science into European and worldwide research.  
 
MOPLT100 Magnetic Structure of the NSC KIPT Nuclear-and-high-energy-physics Electron Accelerator wiggler, vacuum, wakefield, beamloading 764
 
  • I.S. Guk, A. Dovbnya, S.G. Kononenko, F.A. Peev, A.S. Tarasenko
    NSC/KIPT, Kharkov
  • J.I.M. Botman, M.J. Van der Wiel
    TUE, Eindhoven
  Design options of the magnetic structure of a new proposed accelerator facility at NSC KIPT with a continuous-wave electron beam are described. The accelerator represents a recirculator, based on standard TESLA superconducting accelerating sections in one or two straight sections with a length of 5 or 19 meters. The magnetic system is designed on the basis of the magnetic elements of storage ring EUTERPE, transferred by Eindhoven University to NSC KIPT. The focusing and dispersion functions for several design choices of the magnetic structure are reported. Modeling of the beam movement in the accelerator has been carried out; the beam parameters during acceleration and on accelerator output have been calculated.  
 
TUZACH02 Ultra-high Gradient Compact Accelerator Developments gun, injection, positron, focusing 74
 
  • G.J.H. Brussaard, M.J. Van der Wiel
    TUE, Eindhoven
  Continued development of relatively compact, although not quite 'table-top', lasers with peak powers in the range up to 100 TW has enabled laser-plasma-based acceleration experiments with amazing gradients of up to 1 TV/m. In order to usefully apply such gradients to 'controlled' acceleration, various hurdles need to be overcome. The main one is that of well-synchronized injection into a sub-mm to micron wavelength plasma wave. The talk will describe the various physics regimes of laser wakefield acceleration, and the two classes of experiments being pursued. One is that of atmospheric-density plasmas, non-linear wakefields with extreme gradients (hundreds of GV/m)and 'internal injection' of few-femtosecond electron bunches. A second class involves modest-density plasmas,wakefields of order 1 GV/m and external injection of (sub)-ps bunches. The state-of-the-art of these experiments will be covered, including the progress on plasma waveguiding of TW pulses over many diffraction lengths. The talk will also provide an outlook for the coming few years. This part includes proposed schemes for improvements in the area of injection, such as 'all-optical' injection and injection based on GV/m 'pulsed-DC' photoguns.  
Video of talk
Transparencies
 
TUZBCH01 Beam Quality Preservation in the CERN PS-SPS Complex gun, positron, focusing, synchrotron 78
 
  • G. Arduini
    CERN, Geneva
  The LHC will require beams of unprecedented transverse and longitudinal brightness. Their production imposes tight constraints on the emittance growth in each element of the LHC injector chain, namely the PS-SPS Accelerator Complex. The problems encountered at the different stages of the acceleration in the complex span a wide range of topics, such as injection matching, RF gymnastics, space charge, transverse and longitudinal single- and coupled-bunch instabilities, and electron cloud effects. The measurement techniques developed and applied to identify and study the various sources of emittance dilution to the high precision required for the LHC beams and the solutions found to control such phenomena are illustrated.  
Video of talk
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TUZBCH02 Beam Dynamics Challenges for Future Circular Colliders gun, positron, focusing, synchrotron 83
 
  • F. Zimmermann
    CERN, Geneva
  The luminosity of circular colliders rises with the beam intensity, until some limit is encountered, mostly due to head-on and long-range beam-beam interaction, due to electron cloud, or due to conventional impedance sources. These limitations can be alleviated, if not overcome, by a proper choice of beam parameters and by dedicated compensation schemes. Examples include the alternating crossing at several interaction points, electromagnetic wires, super-bunches, electron lenses, clearing electrodes, and nonlinear collimation. I illustrate the benefit from such mitigating measures for the Tevatron, the LHC, the LHC Upgrade, the VLHC, the super e+e- factories, or other projects, and I describe related research efforts at FNAL, KEK, BNL and CERN.  
Video of talk
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TUXLH01 Machine Protection Issues and Strategies for the LHC gun, positron, focusing, synchrotron 88
 
  • R. Schmidt, J. Wenninger
    CERN, Geneva
  For nominal beam parameters at 7 TeV/c, each of the two LHC proton beams has a stored energy of 350 MJ threatening to damage accelerator equipment in case of uncontrolled beam loss. Since the beam dump blocks are the only element of the LHC that can withstand the impact of the full beam, it is essential for the protection of the LHC that the beams are properly extracted onto the dump blocks in case of emergency. The time constants for failures leading to beam loss extend from 100 microseconds to few seconds. Several protection systems are designed to ensure safe operation, such as beam instrumentation, collimators and absorbers, and magnet protection. Failures must be detected at a sufficiently early stage and transmitted to the beam interlock system that triggers the beam dumping system. The strategy for the protection of the LHC will be illustrated starting from some typical failures.  
Video of talk
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TUXLH02 HERA Performance Upgrade: Achievements and Plans for the Future gun, positron, focusing, luminosity 93
 
  • M.G. Minty
    DESY, Hamburg
  Having surpassed the design luminosity of 1.5 x 1031/cm2s already in 1997, an ambitious upgrade of the HERA proton-lepton collider was undertaken in 2000/2001 to provide both higher luminosity and longitudinally polarized lepton beams in the colliding beam experiments, H1 and ZEUS, and for the internal gas target experiment, HERMES. Routine operation following the upgrade has commenced. Initially experimental backgrounds limited the total beam currents so the number of colliding bunches was reduced while maintaining high single-bunch beam currents. With nominal, pre-upgrade, bunch currents the measured specific luminosity is 2.5 times higher than before, however about 15% smaller than design. Following modifications to alleviate the high backgrounds in 2003, HERA is now again operating with the design number of bunches and the total beam currents are being steadily increased. With only 40% of the total design current, peak luminosities of 2.5 x 1031/cm2s have been demonstrated with a longitudinal polarization of >40%. In this presentation the experiences from the upgrade commissioning will be reviewed. Plans for improvement and pronections for the future will be described.  
Video of talk
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TUXLH03 RHIC Performance and Plans Towards Higher Luminosity and Higher Polarization gun, positron, focusing, proton 98
 
  • T. Satogata
    BNL, Upton, Long Island, New York
  RHIC is the first hadron collider consisting of two independent rings. It is designed to operate over a wide range of beam energies and species, including polarized protons, heavy ions, and asymmetric beam collisions. RHIC has produced physics data at four experiments since 1999 in runs that include gold-on-gold collisions at design beam energy (100 GeV/u), high-energy polarized proton-proton collisions (100 GeV on 100 GeV), and deuteron-gold collisions (100 GeV/u). Recent machine performance will be reviewed for high-luminosity gold-gold operations and polarized proton operations, including causes and solutions for known operational limits. Plans and progress for luminosity and polarization improvements, electron cooling, and the electron-ion collider eRHIC will be discussed.  
Video of talk
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TUYLH01 Proton and Ion Sources for High Intensity Accelerators gun, positron, focusing, proton 103
 
  • R. Scrivens
    CERN, Geneva
  Future high intensity ion accelerators, including SNS, European Spallation Source, SPL etc, will require high current and high duty factor sources for protons, negative hydrogen and heavier ions. In order to achieve these goals, a comparison of the Electron Cyclotron Resonance, radio-frequency and Penning ion sources, among others, will be made. For each of these source types, the present operational sources will be compared to the state-of-the-art research devices with special attention given to reliability and availability. Finally, the future research and development aims will be discussed.  
Video of talk
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TUYLH02 Low and Medium Energy Beam Acceleration in High Intensity Linacs gun, positron, focusing, synchrotron 108
 
  • J. Stovall
    LANL, Los Alamos, New Mexico
  In the past two years accelerator builders have published papers describing mature designs of no fewer than 7 new high-performance proton linacs. These machines are typically designed to deliver multi-megawatt beams for applications in pure and applied research. All of these machines use the radio-frequency quadrupole (RFQ) linac for the first stage of acceleration to reach an energy of a few MeV. In essentially all cases, superconducting elliptical cavities have been adopted as the technology of choice for acceleration above ~100 MeV. Between the RFQ and the high-energy elliptical cavities, designers have proposed no fewer than 6 different types of accelerating structures. In many cases these structures are reaching maturity as a result of active development programs. In this paper, we review the design architectures of the ?low and medium energy? portions of these machines emphasizing recent experience and developments applicable to high-current linac designs.  
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TUYLH03 Challenges facing the Generation of MW Proton Beams using Rapid Cycling Synchrotrons gun, positron, focusing, radiation 113
 
  • Y. Irie
    KEK, Ibaraki
  The MW proton source using rapid cycling synchrotron (RCS) has many challenging aspects, such as (1) large aperture magnets and much higher RF voltages per turn due to a low energy injection and a large and rapid swing of the magnetic field, (2) field tracking between many magnet-families under slightly saturated conditions, (3) RF trapping with fundamental and higher harmonic cavities, (4) H- charge stripping foil, (5) large acceptance injection and extraction straights, (6) beam loss collection, and (7) beam instabilities. These are discussed in details mainly on the basis of the J-PARC 3GeV RCS, which is under construction in Japan. Issues (3) to (7) are common with another scheme of MW spallation neutron source, i.e. full-energy linac + accumulator ring. Comparisons with the SNS design in the US are then made. Reliability/availability of these machines is very important theme which finally determines the successful operations. From the experiences in the existing machines, we will discuss the factors necessary toward the better performance.  
Video of talk
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TUPKF001 Upgrade and Commissioning of the LNLS RF System gun, positron, focusing, beamloading 950
 
  • R.H.A. Farias, N.P. Abreu, L.C. Jahnel, L. Liu, C. Pardine, P.F. Tavares
    LNLS, Campinas
  In this paper we present a report on the commissioning of the new RF system of the electron storage ring of the brazilian synchrotron radiation facility (LNLS).  
 
TUPKF002 TRIUMF ISAC II RF Control System Design and Testing gun, positron, focusing, beamloading 953
 
  • M.P. Laverty, S.F. Fang, K. Fong
    TRIUMF, Vancouver
  The rf control system for the ISAC II superconducting cavities is a hybrid analogue/digital design which has undergone several iterations in the course of its development. In the current design, the cavity operates in a self-excited feedback loop, while phase locked loops are used to achieve frequency and phase stability. Digital signal processors are used to provide amplitude and phase regulation, as well as mechanical cavity tuning control. The most recent version also allows for the rapid implementation of operating firmware and software changes, which can be done remotely, if the need arises. This paper describes the RF control system and the experience gained in operating this system with a four-cavity test facility.  
 
TUPKF003 Industrial Production of the Eight Normal-conducting 200 MHz ACN Cavities for the LHC gun, positron, focusing, beamloading 956
 
  • R. Losito, E. Chiaveri, R. Hanni, T.P.R. Linnecar, S. Marque, J. Tuckmantel
    CERN, Geneva
  The LHC-ACN RF system consists of 8 normal-conducting cavities and is designed to reduce beam losses in the LHC when injecting beams with longitudinal emittance > 0.7 eVs from the CERN SPS. The cavity design took into account the possibility of recuperating all the "ancillary" equipment (tuners, fundamental mode damper, High Order Mode (HOM) couplers) from the old CERN SPS 200MHz system. The cavities are made from OFE copper. The original ingots, procured in Austria, have been forged and pre-formed by pressing them with a 20 tons press, following a procedure defined and adapted for the unusual dimensions of these pieces. The raw components thus obtained were machined and then welded together with an electron beam. In order to get a good repeatability of the fundamental mode frequency across the eight cavities, a procedure has been established with the contractor for the final machining and welding leading to a spread in frequencies below ±20 kHz (< 0.01%). The cavities will be installed in the LHC when losses at high intensities become significant. In the meantime they are undergoing a surface treatment to clean the RF surface and will be stored.  
 
TUPKF004 First Results with a Fast Phase and Amplitude Modulator for High Power RF Application gun, positron, focusing, beamloading 959
 
  • D. Valuch, H. Frischholz, J. Tuckmantel
    CERN, Geneva
  • C. Weil
    AFT, Backnang
  In a high energy and high power superconducting proton linac, it is more economical to drive several cavities with a single high power transmitter rather than to use one transmitter per cavity. This option has however the disadvantage of not permitting to individually control each cavity, which potentially leads to instabilities. Provided that it can be built at a reasonable cost, a fast phase & amplitude modulator inserted into each cavity feeder line can provide the necessary control capability. A prototype of such a device has been built, based on two fast and compact high power RF phase-shifters, magnetically biased by external coils. The design is described, together with the results obtained at high and low power levels.  
 
TUPKF005 Inductive Output Tube Based 300 kW RF Amplifiers for the Diamond Light Source gun, positron, focusing, beamloading 962
 
  • J. Alex, M. Brudsche, M. Frei, M. Müller, A. Spichiger
    Thales Broadcast & Multimedia AG, Turgi
  • M. Jensen
    Diamond, Oxfordshire
  All currently operating synchrotron light sources use klystron amplifiers to generate the RF power for the accelerator cavities. In TV broadcasting systems on the other hand, Inductive Output Tubes (IOT)are replacing the classical klystron based systems in all new high power UHF transmitters. The Diamond Light Source will be the first synchrotron to be operated using IOTs. For each accelerating cavity a total of four IOTs will be combined with a waveguide combiner to achieve the RF power requirement of 300 kW at 500 MHz. All IOTs will be supplied from a common crowbarless high voltage power supply. Three such systems will be installed starting in October 2004. This paper gives an overview of the design of the amplifiers, including the first test results from the factory commissioning.  
 
TUPKF006 Custom Design of Medium Energy Linear Accelerator Systems gun, positron, focusing, beamloading 965
 
  • K. Dunkel, M. Pekeler, C. Piel, H.P. Vogel, P. vom Stein
    ACCEL, Bergisch Gladbach
  Based on customer requirements ACCEL Instruments is designing and building medium energy turn-key Linear Accelerator Systems for scientific applications. Within this paper design and performance of third generation synchrotron light source electron injector linacs will be presented. Further the design of a medium energy light ion linear accelerator will be discussed. This light ion accelerator is designed with independently phased superconducting rf cavities for cw operation and acceleration of different particle species and a variable Energy output.  
 
TUPKF007 Series Fabrication Technologies for Normalconducting Linac and Storage Ring Cavities gun, positron, focusing, beamloading 968
 
  • P. vom Stein, K. Dunkel, B. Griep, C. Piel, H.P. Vogel
    ACCEL, Bergisch Gladbach
  Twelve HOM damped 476 MHz single cell cavities have been delivered for PEP II and the production of several 805 MHz CCL modules for SNS has recently been finalised by ACCEL Instruments. Based on those two examples, required key technologies for cavity production will be introduced. Final prove of successful manufacturing is given by low level rf measurements. Results of those measurements for above mentioned projects will be presented within this paper.  
 
TUPKF008 Status of the HoBiCaT Superconducting Cavity Test Facility at BESSY gun, positron, focusing, beamloading 970
 
  • J. Knobloch, W. Anders, J. Borninkhof, S. Jung, M. Martin, A. Neumann, D. Pflückhahn, M. Schuster
    BESSY GmbH, Berlin
  BESSY has recently constructed the HoBiCaT cryogenic test facility for superconducting TESLA cavity units, including all ancillary devices (helium tank, input coupler, tuner, magnetic shielding). It is designed to house two such units in a configuration similar to that envisaged for the superconducting CW linac of the BESSY FEL. These units are presently being fabricated, prepared and assembled by industry. HoBiCaT will be used to address many of the issues that must be considered prior to finalizing the design of the proposed linac. Rapid turn-around-tests permit the investigation of items such as RF regulation, microphonic detuning and cryogenic parameters/achievable pressure stability. These test will also serve as the first step towards qualifying the industrial production of assembled cavity units. The commissioning of HoBiCaT is scheduled for Spring 2004 and the current status is presented here.  
 
TUPKF009 RF Control of the Superconducting Linac for the BESSY FEL gun, positron, focusing, beamloading 973
 
  • J. Knobloch, A. Neumann
    BESSY GmbH, Berlin
  In the BESSY-FEL superconducting linac, precise RF control of the cavities' voltage is imperative to maintain a bunch-to-bunch time jitter of less than 50 fs for synchronization in the HGHG section. The average beam loading is less than 1.5 kW/m and the cavity bandwidth is small so that high-gain RF feedback is required. Noise, in particular microphonic detuning, strongly impact the achievable level of control. Presented here are simulations of the cavity-feedback system, taking into account beam loading and noise sources such as measurement noise, microphonics and injection jitter. These simulations are used to estimate the resultant time and energy jitter of the bunches as they enter the HGHG section of the BESSY FEL.  
 
TUPKF010 Cryogenic Considerations for CW Operation of TESLA-type Superconducting Cavity Modules for the BESSY FEL gun, positron, focusing, beamloading 976
 
  • J. Knobloch, W. Anders, X. Yu
    BESSY GmbH, Berlin
  The proposed BESSY FEL uses a CW superconducting driver linac to provide acceleration up to 2.3 GeV. Its design is based on well-established TESLA technology, originally intended for heat loads of order 1 W/m at 2.0 K. CW operation increases this load to levels of order 15 W/m at 1.8 K for a total heat load of 3 kW at 2.3 GeV (given conservative assumptions for the attainable Q-factor). Presented here is an analysis of the cryogenic layout, including two-phase-flow simulations of the 1.8-K helium which help identify the changes needed for reliable CW operation. A modified ‘‘CW'' module and helium distribution scheme is proposed.  
 
TUPKF011 First Tests of a HOM-Damped High Power 500MHz Cavity gun, positron, focusing, beamloading 979
 
  • F. Marhauser, E. Weihreter
    BESSY GmbH, Berlin
  A prototype high power 500 MHz copper cavity with three tapered circular waveguides for broadband higher order mode (HOM) damping has been fabricated especially for the use in 3rd generation synchrotron radiation sources. Low power impedance measurements are presented and compared with theoretical simulations to verify the expected HOM damping efficiency as well as the fundamental mode shunt impedance. After a careful cleaning and baking process to reduce the vacuum pressure the cavity has been conditioned at high power. All relevant parameters of the cavity are reported.  
 
TUPKF012 A HOM Damped Planar Accelerating Structure gun, positron, damping, focusing 982
 
  • A. Blednykh, H. Henke
    TET, Berlin
  The problem of very fast higher order mode (HOM) suppression, in the order of 1ns, was investigated for a planar 30GHz accelerating structure. Both, damping and detuning were considered. A sufficient suppression could be achieved by damping waveguides in every cell in vertical and in horizontal direction. Finally, a scaled-up 10GHz model was built. It is a 35 cm long aluminum structure, which was machined by high-precision milling. In order to reduce the surface gradient on the input/output coupling irises a symmetrical RF coupler was developed. The HOM damping is accomplished by coupling six damping waveguides to each accelerating cell. The waveguides are loaded by a low resitivity RF load. The whole structure with waveguides and loads was optimized by means of the computer code GdfidL. The paper gives the design criteria and the results of s-parameter and bead-pull measurements.  
 
TUPKF013 Studies on Maximum RF Voltages in Ferrite-tuned Accelerating Cavities gun, positron, damping, focusing 985
 
  • K. Kaspar, H.G. Koenig, T. Winnefeld
    GSI, Darmstadt
  The GSI SIS100 project requires very high accelerating voltages. With ferrite-tuned synchrotron cavities the gap voltage is often strongly limited by the Q-loss effect appearing at medium dc bias fields. At low bias fields, considerably higher voltages can be reached, however. The maximum usable amplitudes over the bias region have been studied. At zero bias, the ferrites could be driven to more than a factor 3 above the Q-loss limit. Except overheating, no other problems appeared. With increasing bias, the maximum amplitudes decrease continuously to the Q-loss level. In this fall-off region there is still a tuning factor up to 2.5 available, with rf flux densities by at least a factor 2 above the Q-loss level. Measurements on small samples of the ferrite material used in the GSI cavities could be verified very well in a full-size cavity, for the most part. The tests were mainly limited by the available anode voltage and the fear of damaging the cavity. It seems possible, to generalize the main results for other ferrite materials, also. Based on the results, a possible scenario for the SIS100 rf system is given. Additionally, the results lead to an alternative cavity design for higher voltages, which is described as well.  
 
TUPKF014 Electromagnetic Design of New RF Power Couplers for the S-DALINAC gun, positron, damping, focusing 988
 
  • M. Kunze, W.F.O. Müller, T. Weiland
    TEMF, Darmstadt
  • M.B. Brunken, H.-D. Gräf, A. Richter
    TU Darmstadt, Darmstadt
  New rf power couplers for the Superconducting Darmstadt Linear Accelerator (S-DALINAC) injector have to be designed to transfer rf power up to 2 kW to the electron beam. This allows injector operation at beam currents from 0.15 mA to 0.2 mA and electron energies up to 14 MeV. The new couplers should possibly provide a variable external Q in the range from 5·106 to 3·109 and a small transverse kick. A variable coupling is needed to allow for perfect matching in the case of beam loading and when no beam is present, respectively. The second operation stage is used for cavity diagnostics. The asymmetric field distribution of the couplers generates emittance growth of the electron beam and therefore the transverse kick has to be minimized. Electromagnetic simulations are applied to investigate different coupler designs and to localize possible problems at an early stage. Cavity external Q and transverse kick can be calculated from 3D electromagnetic eigenmode solutions. The present coaxial-coaxial input couplers at the S-DALINAC are limited to power operation below 500 W under full reflection. Therefore, to reach power operation up to 2 kW two possible new realizations of low-kick waveguide couplers for the S-DALINAC injector are presented, namely a single-waveguide and a twin-waveguide coupler.  
 
TUPKF015 Status of the Superconducting CH-Structure gun, positron, damping, focusing 991
 
  • H. Podlech, H. Deitinghoff, H. Klein, H. Liebermann, U. Ratzinger, A.C. Sauer, R. Tiede
    IAP, Frankfurt-am-Main
  H-mode cavities (IH-DTL, IH-RFQ, 4-Vane-RFQ) have been developed and operated successfully during the last decades for ion acceleration. At the IAP Frankfurt a new type of H-mode cavity, the CH-structure is under development. This multi cell drift tube cavity is operated in the TE21- mode. Due to its mechanical rigidity, room temperature as well as superconducting versions can be realized. Superconducting CH-structures might be used especially for cw operated linacs in nuclear research facilites and applied research projects like XADS or IFMIF. A superconducting 352 MHz CH-structure (beta=0.1) with 19 gaps will be available for first tests in 2004. We present the status of the cavity and of the new cryo laboratory in Frankfurt.  
 
TUPKF016 Dynamic Lorentz Force Detuning Studies in TESLA Cavities gun, positron, damping, focusing 994
 
  • V. Ayvazyan, S. Simrock
    DESY, Hamburg
  Dynamic detuning of the superconducting rf cavities due to Lorentz force induced mechanical excitation is a critical concern since the magnitude can approach the cavity bandwidth and require significant additional rf power for field control. In this paper, the influence of high accelerating fields on the resonance frequency in superconducting TESLA cavities is discussed. Cavities at the TESLA Test Facility have been operated at the design operating gradient close to 25 MV/m. It is shown that Lorentz force detuning constant factors are different for different cavities, significant spread have been observed.  
 
TUPKF017 Electrons Beam Dynamics of the 100 MeV Preinjector Helios for the SOLEIL Synchrotron positron, damping, focusing, linac 997
 
  • A.S. Setty
    THALES, Colombes
  A 100 MeV electron linac is under construction, in order to inject into the booster synchrotron of SOLEIL. The linac is designed to work according to two operation modes : a short pulse mode (2 ns - 0,5 nC) and a long pulse mode (300 ns - 8 nC). Calculation of the beam dynamics, using our selfmade code PRODYN, has been carried out from the gun to the end of the linac. Special care has been taken on the gun design to avoid an overfocusing outcoming beam in order to obtain a final low emittance. Calculations results are given.  
 
TUPKF018 Surface Morphology at the Quench Site positron, damping, focusing, linac 1000
 
  • S. Berry, C.Z. Antoine, M. Desmons
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  It has been demonstrated recently that local magnetic field enhancement can originate from roughness (e.g. steps at grain boundaries). We are willing to investigate if the quench observed in superconducting niobium cavities can be related to such morphological defects. We recently developed two kinds of tool. 1) A replica technique that allows to reproduce the internal surface of cavities (non destructive testing). 2) A morphological analysis tool. Classical roughness measurements are not adapted to determine local curvature radius.This paper describes a new topological approach aiming at a better characterization of the surface morphology. We also present results of this technique applied to replica taken from cavities at the quench site.  
 
TUPKF019 Recent Developments on Superconducting b035 and b015 Spoke Cavities at IPN for Low and Medium Energy Sections of Proton Linear Accelerators. positron, damping, focusing, linac 1003
 
  • G. Olry, J.-L. Biarrotte, S. Blivet, S. Bousson, F. Chatelet, D. Gardès, N. Hammoudi, T. Junquera, J. Lesrel, C. Miélot, A.C. Müller, D. Ruffier, H. Saugnac, P. Szott, J.P. Thermeau
    IPN, Orsay
  Spoke cavities studies leaded by IPN-Orsay, for both XADS and EURISOL projects, are fully integrated within the 5th and 6th European Framework Programs. During 2003, several tests have been performed on the first b035 spoke cavity prototype. They have demonstrated the great potential of this type of cavity in term of RF performances (Eacc max=12.5 MV/m at T=4.2 K) and mechanical behavior (very low sensitivity to errors fabrication, good stiffness…). Following the upgrade of our cryogenic facility, we have tested, this spring, the cavity at 2 K. These new results will be presented in this paper. In parallel, the fabrication of a new spoke cavity (2-gap, 352 MHz, b015) has begun in January. While keeping the same geometry than that of the b035 cavity, we carried out significant changes on the coupler port and stiffening system designs. We report here in particular, RF calculations concerning the new location of the coupler port (in order to minimize losses due to magnetic field) and also, mechanical calculations about the new stiffening ring. Finally, we will present the preliminary thought on modular cryomodule which are based on the ?short? cryomodule concept used with the Quarter Wave Resonators for the SPIRAL-2 project.  
 
TUPKF020 Numerical Investigation on the ELETTRA 500 MHz Power Coupler positron, damping, focusing, linac 1006
 
  • C. Pasotti, P. Craievich, A. Fabris, G. Penco, M. Svandrlik
    ELETTRA, Basovizza, Trieste
  • B. B. Baricevic
    DEEI, Trieste
  Due to the high input power required to feed a resonant cavity, the RF input coupler is a critical component for the reliability of an RF system. The 500 MHz RF input coupler for the ELETTRA cavities was specified for 150 kW input power. It is important to investigate the performance limits of the coupler in view of increasing RF power requirements. The coupler's maximum peak field and dissipation versus the input power have been studied by means of the numerical simulator HFSS. Possible improvements to the existing design have been investigated. The optimization has to take into consideration the following requirements: convenient power transmission efficiency, RF matching, suitable coupling coefficient, negligible perturbation on cavity voltage, moderate operating temperature and stress.  
 
TUPKF021 First Year of Operation of SUPER-3HC at ELETTRA positron, focusing, linac, beamloading 1009
 
  • G. Penco, P. Craievich, A. Fabris, C. Pasotti, M. Svandrlik
    ELETTRA, Basovizza, Trieste
  Since July 2003 a superconducting third harmonic cavity has been in routine operation at ELETTRA. When the cavity is activated the stored electron bunches are lengthened by about a factor of three. The related longitudinal Landau damping has allowed first time operation at 320 mA, 2.0 GeV with a beam completely free of longitudinal coupled bunch instabilities. With the cavity active the lifetime at 320 mA, 2.0 GeV is three times the theoretical value for nominal bunch length. The increase in beam stability and lifetime contributed significantly to enhance the brightness and the integrated flux of the source. We will further discuss the operating experience with the superconducting cavity and the cryogenic system, analyzing the impact of the new system on machine operation and uptime. Finally we will also report on the characterization of the cavity performance for different filling patterns of the storage ring and relate the results to preliminary beam-cavity interaction studies.  
 
TUPKF022 Constructionand Testing of the Beta=0.31, 352 MHz Superconducting Half-wave Resonator for the SPES Project positron, focusing, linac, beamloading 1012
 
  • A. Facco, W. Lu, F. Scarpa
    INFN/LNL, Legnaro, Padova
  • E. Chiaveri, R. Losito
    CERN, Geneva
  • V. Zviagintsev
    TRIUMF, Vancouver
  The interest in low- and medium- beta superconducting cavities is presently focused to future high intensity proton, deuteron and heavy ion linacs. A particular application is acceleration of cw and pulsed beams of variable q/A, which requires cavities with a small number of gaps and excellent mechanical stability. We have designed and constructed a 2 gap, 352 MHz SC half wave cavity aiming to similar characteristics and fitting the requirements of the intermediate-beta section of the LNL-SPES driver. The status of the project and the first test results will be presented.  
 
TUPKF023 Construction of a 161 MHz, beta=0.16 Superconducting QWR with Steering Correction for RIA positron, focusing, linac, beamloading 1015
 
  • A. Facco, W. Lu, F. Scarpa
    INFN/LNL, Legnaro, Padova
  • E. Chiaveri, R. Losito
    CERN, Geneva
  • T.L. Grimm, W. Hartung, F. Marti, R.C. York
    NSCL, East Lansing, Michigan
  • V. Zviagintsev
    TRIUMF, Vancouver
  We have built a 161 MHz, b=0.16 superconducting Quarter Wave Resonator with steering correction for the low beta section of RIA. This bulk niobium, double wall cavity, compatible with both separate vacuum between beam line and cryostats or unified one, was designed in collaboration between MSU-NSCL and LNL. The design is suitable for extension to other frequencies, e.g. to obtain the 80 MHz, beta=0.085 cavity required in RIA. The shaped drift tube allows correction of the residual QWR steering that can cause emittance growth especially in light ions; this could make this resonator a good alternative to Half-Wave resonators in high intensity proton-deuteron linacs, like the SPES injector project at LNL. First test results will be presented.  
 
TUPKF024 Operation Experience with ALPI Nb/Cu Resonators positron, focusing, linac, beamloading 1018
 
  • A.M. Porcellato, L. Bertazzo, M. De Lazzari, D. Giora, V. Palmieri, S. Stark, F. Stivanello
    INFN/LNL, Legnaro, Padova
  The refurbishing, by replacing the Pb superconducting film by Nb, of ALPI QW accelerating resonators was completed in 2003. All the 52 cavities are now in operation showing a large increase in the average accelerating field, which exceeds 4.5 MV/m (21 MV/m pick electrical surface field). The performance of renewed resonators has been increasing with time reaching 6MV/m in the last produced units. The increase in ALPI performance and the advantage in conditioning and setting time obtained by the upgrading process will be reported.  
 
TUPKF025 Superconducting Niobium Film for RF Applications positron, focusing, linac, beamloading 1021
 
  • A. Cianchi, L. Catani, A. Cianchi, S. Tazzari
    INFN-Roma II, Roma
  • Y.H. Akhmadeev
    Institute of High Current Electronics, Tomsk
  • A. Andreone, G. Cifariello, E. Di Gennaro, G. Lamura
    Naples University Federico II, Napoli
  • J.L. Langner
    The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
  • R.R. Russo
    Università di Roma II Tor Vergata, Roma
  Thin niobium film coated copper RF cavities are an interesting possible alternative to bulk-Nb cavities since copper is much cheaper than niobium, it has higher thermal conductivity and a better mechanical stability. Unfortunately, the observed degradation of the quality factor with increased cavity voltage of sputtered accelerating cavities restricts their usage in future large linear accelerators needing gradients higher than 15MV/m. We are developing an alternate deposition technology, based on a cathodic arc system working in UHV conditions. Its main advantages compared to standard sputtering are the ionized state of the evaporated material, the absence of gases to sustain the discharge, the much higher energy of atoms reaching the substrate surface and the possibility of higher deposition rates. To ignite the arc we use a Nd-YAG pulsed laser focused on the cathode surface that provides a reliable and ultraclean trigger. Recent results on the characterization of niobium film samples produced under different conditions are presented showing that the technique can produce bulk-like films suitable for RF superconducting applications.  
 
TUPKF026 RF Tests of the Beta=0.5 Five Cell TRASCO Cavities positron, focusing, linac, beamloading 1024
 
  • A. Bosotti, C. Pagani, P. Pierini
    INFN/LASA, Segrate (MI)
  • J.P. Charrier, B. Visentin
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • G. Ciovati, P. Kneisel
    Jefferson Lab, Newport News, Virginia
  Two complete 5 cell superconducting cavities at b=0.5 have been designed and fabricated. The cavities have been designed to minimize peak electric and magnetic fields, with a goal of 8.5 MV/m of accelerating gradient, at a Q > 5E9. The cavities are currently in the testing stage and the results of the vertical tests will be presented at this conference.  
 
TUPKF031 Non-resonant Accelerating System at the KEK-PS Booster positron, focusing, linac, booster 1027
 
  • S. Ninomiya, M. Muto, M. Toda
    KEK, Ibaraki
  The non-resonant accelerating system for the KEK-PS booster accelerator has been constructed. The system has been operating since October 2003 without trouble. The accelerating gap in the system is loaded with magnetic cores of high permeability. The cores produce high resistive impedance at the gap. The power dissipated in the cores amounts to 50kW at 16kV accelerating voltage. It is removed by forced-air cooling system. At the last operation of the accelerator, with the help of new COD-correction system, the average beam intensity of the booster increased to 2.6E+12ppp, which is 30% higher than before.  
 
TUPKF032 COD Correction by Novel Back-leg at the KEK-PS Booster positron, focusing, linac, booster 1030
 
  • S. Ninomiya, K. Satoh, H. Someya, M. Toda
    KEK, Ibaraki
  The COD correction is performed by using new driving system of back-leg windings. Two back-leg coils of the separate magnets are connected to make a closed circuit in which the induced voltages of the two magnets have opposite phases to each other. When the current source is inserted into the closed loop, the current drives the two magnets with opposite polarities. If the pair of magnets is properly selected, the current effectively corrects the orbit distortion. The selection rule of the pair is as follows; one is the magnet at the maximum distortion and the second magnet is that separated with the betatron phase of -90deg. The correction system at the KEK-PS Booster reduced the COD to less than 1/5 of that without correction, and increased the capture efficiency. The average beam intensity of our Booster is increased from 2E+12 to 2.6E+12ppp.  
 
TUPKF033 Cryogenic Performance of the Prototype Cryomodule for ADS Superconducting LINAC positron, focusing, booster, beamloading 1033
 
  • N. Ohuchi, E. Kako, S. Noguchi, T. Shishido, K. Tsuchiya
    KEK, Ibaraki
  • N. Akaoka, H. Kobayashi, N. Ouchi, T. Ueno
    JAERI/LINAC, Ibaraki-ken
  • T. Fukano
    Nippon Sanso Corporation, Tokyo
  • H. Hara, M. Matsuoka, K. Sennyu
    MHI, Kobe
  A prottype cryomodule containing two 9-cell superconducting cavities of b=0.725 and f=972MHz is being constructed under the collaboration of Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK) on the development of superconducting LINAC for Accelerator Driven System (ADS). Cryogenic performances of the cryomodule and 2K He-system will be reported.  
 
TUPKF034 Low Output-Impedance RF System for 2nd Harmonic Cavity in the ISIS Synchrotron positron, focusing, impedance, booster 1036
 
  • T. Oki, S. Fukumoto, Y. Irie, M. Muto, S. Takano, I. Yamane
    KEK, Ibaraki
  • R.G. Bendall, I.S.K. Gardner, M.G. Glover, J. Hirst, D. Jenkins, A. Morris, S. Stoneham, J.W.G. Thomason, T. Western
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  • J.C. Dooling, D. Horan, R. Kustom, M.E. Middendorf, G. Pile
    ANL, Argonne, Illinois
  In the ISIS facility based at Rutherford Appleton Laboratory (RAL) in the UK, second target station project was funded, which requires to increase the current intensity by 1.5-times (300 micro-A). Four 2nd harmonic RF cavities will be installed in the ISIS synchrotron in order to increase the trapping efficiency, and to mitigate the space charge detuning. A very low output-impedance RF system for the 2nd harmonic cavity has been developed by the collaboration between RAL, Argonne National Laboratory (US) and KEK (Japan). The system comprises the 240 kW triode as a final amplifier with plate-to-grid feedback path. The measured output-impedance was less than 30 ohms over the frequency range of 2.7 - 6.2 MHz, which agreed well with calculations. High power test was also performed under frequency swept mode at 50 Hz repetition. The operation was almost stable, and more than 12 kVpp was obtained as maximum. The voltage gain of the final amplifier was 25 - 30, which decreased gradually with frequency due to decreasing input-impedance of triode. The beam test is planned at ISIS in near future.  
 
TUPKF035 RF System for Compact Medical Proton Synchrotron positron, focusing, impedance, acceleration 1039
 
  • Z. Fang, K. Egawa, K. Endo, S. Yamanaka
    KEK, Ibaraki
  • Y. Cho, T. Fusato, T. Hirashima
    DKK, Kanagawa
  The rf system has been developed for the compact medical proton synchrotron. The rf system will be operated in pulse mode with the fundamental rf frequency sweeping from 1.6 to 15 MHz during the acceleration time of 5 ms. The required rf cavity voltage is a function of acceleration time too, with the voltage of fundamental varying from 13 to 6 kV. Besides, high order harmonics are also considered to apply to the rf system, and the cavity peak voltage varying from 20 to 9 kV during the acceleration time is expected. The performance of the rf system is being studied and will be presented.  
 
TUPKF036 RF Property of the Prototype Cryomodule for ADS Superconducting Linac positron, focusing, impedance, acceleration 1042
 
  • E. Kako, S. Noguchi, N. Ohuchi, T. Shishido
    KEK, Ibaraki
  • N. Akaoka, H. Kobayashi, N. Ouchi, T. Ueno
    JAERI/LINAC, Ibaraki-ken
  • H. Hara, M. Matsuoka, K. Sennyu
    MHI, Kobe
  A prototype cryomodule containing two 9-cell superconducting cavities of beta=0.725 and frequency=972MHz is being constructed under the collaboration of Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK) on the development of superconducting LINAC for Accelerator Driven System (ADS). Design and performance of RF components will be reported.  
 
TUPKF037 Multi-harmonic RF Acceleration System for a Medical Proton Synchrotron positron, focusing, impedance, booster 1045
 
  • K. Saito, M. Katane, K. Kobayashi, K. Masui, K. Moriyama, H. Nishiuchi, H. Sakurabata, H. Satomi
    Hitachi, Ltd., Power & Industrial Systems R&D Laboratory, Ibaraki-ken
  We have developed an RF accelerating system for medical proton synchrotron. The RF cavity is a tuning-free wideband type, loaded with FINEMET cores, which is driven by a solid-state RF power amplifier with operation frequency range between 1MHz and 10MHz. Multi-harmonic RF acceleration scheme has been realized with the RF control system, to reduce beam loss by space-charge effect in low energy region. The original techniques for high-speed digital signal processing and high-precision RF signal processing have been applied, in order to fulfill feedback control of the frequency, phase and amplitude of the second and third harmonic RF signals as well as the fundamental one.  
 
TUPKF038 Reduced Length Designs of 500 MHz Damped Cavity Using SiC Microwave Absorber positron, focusing, impedance, booster 1048
 
  • T. Koseki
    RIKEN/RARF/BPEL, Saitama
  • M. Izawa, S. Sakanaka, T. Takahashi, K. Umemori
    KEK, Ibaraki
  We present a new 500 MHz HOM (Higher-Order Modes) damped cavity for high brilliance synchrotron radiation sources. The design is based on the damped cavity, which is operated at the Photon Factory storage ring in KEK. The PF cavity has a large hole beam duct (140 mm in diameter), a part of which is made of a silicon carbide (SiC) microwave absorber. The new cavity, proposed in this paper, has parallel-plate radial transmission lines on the beam duct instead of the SiC beam duct. The outer end of the radial line is terminated by SiC absorbers. The HOMs, extracted from the center part of the cavity through the beam duct, propagate in the radial line and are dissipated in the absorber. The accelerating mode is not affected by the radial line damper since the frequency is sufficiently below the cutoff of the 140-mm beam duct. In this paper, optimized design of the radial line damper and damping properties for HOMs are described in detail.  
 
TUPKF039 The Experiences of Operation and Performance about the 500 MHz CW Klystrons at the PLS Storage Ring positron, focusing, impedance, booster 1051
 
  • J.S. Yang, M.-H. Chun, Y.J. Han, S.-H. Nam, I.H. Yu
    PAL, Pohang
  There are four RF stations to supply the energy to electron at the storage ring of the Pohang Light Source(PLS). From the beginning of the operation of RF system, 500MHz 60kW(CW) klystrons have been operated. As the operation time of the tubes are increased, their performances are decreased. Therefore three 60kW tubes were replaced with the same model and two 75kW klystrons were replaced with 60 kW klystrons so far. Nowadays two 75 kW and two 60 kW klystrons are operated in the RF system of PLS. Our experiences of the klystron operation and their general performance are described in this paper.  
 
TUPKF041 Quasi-optic RF Power Transmission Line from a FEM Oscillator to the Model of the CLIC Accelerating Structure positron, focusing, impedance, booster 1054
 
  • A. Kaminsky, A.V. Elzhov, E.A. Perelstein, N.V. Pilyar, T.V. Rukoyatkina, S. Sedykh, A.P. Sergeev, A. Sidorov
    JINR, Dubna, Moscow Region
  • N.S. Ginzburg, S.V. Kuzikov, N.Yu. Peskov, M.I. Petelin, A. Sergeev, N.I. Zaitsev
    IAP/RAS, Nizhny Novgorod
  Experimental investigation of a copper resonator lifetime under multiple action of 30 GHz power pulses is now carried out by the collaboration of CLIC team (CERN), FEM group of JINR (Dubna) and IAP RAS (Nizhny Novgorod). A quasi-optic two-mirror transmission line is used between the FEM oscillator and test cavity. An oversized FEM output waveguide based on the wavebeam transformation (Talbot effect) provides the optimal transverse distribution of the radiation, eliminates the output window breakdown and decrease the influence of the reflected wave on the FEM oscillator regime.  
 
TUPKF048 Studies of Electron Multipacting in CESR Type Rectangular Waveguide Couplers positron, focusing, impedance, booster 1057
 
  • P. Goudket, M. Dykes
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • S.A. Belomestnykh, R. Geng
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • R.G. Carter
    Microwave Research Group, Lancaster University, Lancaster
  • H. Padamsee
    Cornell University, Ithaca, New York
  The latest results from an experimental waveguide section, as well as simulations from a model of electron multipacting using the MAGIC PIC code, are discussed. Tests were carried out on a new waveguide section that included enhanced diagnostics and the possibility of changing surface materials and temperature. Those tests evaluated grooves, ridges and surface coatings, such as TiN and a TiZrV NEG coating, as methods of multipactor suppression. The conclusion remains that the most effective method to achieve complete multipactor suppression remains the application of a static magnetic bias of approximately 10G. The experiments also provided good data sets that can be used to verify the accuracy of simulations. Simulations of the waveguide multipacting have been carried out and have offered better understanding of electronic behaviour.  
 
TUPKF049 Combining Cavity for RF Power Sources: Computer Simulation and Low Power Model positron, focusing, impedance, booster 1060
 
  • E. Wooldridge, S.C. Appleton, B. Todd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  A combining cavity for RF power sources has been investigated as a way of saving space, in comparison to waveguides, and as a way of combining power with graceful degradation if one or more component were to fail. The cavity has been investigated as the maximum power output of an Inductive Output Tube (IOT) for CW is 80KW at 500MHz and a proposed output of 20KW at 1.3GHz and most RF systems for particle accelerators require much more than this. Although 1.3GHz klystrons do exist they are vastly more expensive to purchase and maintain. Also the down time could be minimised to minutes in the even of a single IOT failure where as a klystron has a minimum downtime of several days in the event of a failure. Initially the cavity and its inputs were simulated in CSTs? Microwave studio. After optimising the cavity to ensure the minimum reflection at the input ports and maximum transmission at the output port, a low power model was then created from aluminium. Signal generators were used to power the model and a network analyser was used to check the output. The model was used to compare the results gained from the computer simulation and to obtain results from asymmetric positioning of the ports, which was not possible in the simulation.  
 
TUPKF050 Triggers for RF Breakdown positron, focusing, impedance, booster 1063
 
  • J. Norem, Z. Insepov
    ANL, Argonne, Illinois
  We outline a model of breakdown in rf cavities. Breakdown can be triggered by two mechanisms, one is fracture of the surface due to the tensile stress produced by the electric field, the second is Ohmic heating at grain boundaries and defects at very high current densities. We show how this model follows from measurements of local electric fields using electron field emission, and show how the model applies to the operating conditions of a variety of rf structures. This model may have some relevance to SCRF and DC structures.  
 
TUPKF051 A 500 kV Power System for a Gridded Sheet-beam Klystron klystron, positron, focusing, cathode 1066
 
  • M.A. Kempkes, F.O. Arntz, J.A. Casey, M.P.J. Gaudreau, N. Reinhardt, R.P. Torti
    Diversified Technologies, Inc., Bedford
  The Next Generation Linear Collider (NLC) will require hundreds of X-band high power klystrons. These klystrons are typically cathode pulsed at 500 kV and 265 A each, with 1.6 microsecond pulses of RF, and a complex microwave delay line to achieve 400 ns RF pulses. Because the pulsed voltage is so high, CV2f losses will lead to many millions of dollars per year of wasted power. The klystron group at SLAC, working with Calabazas Creek Research (CCR), is developing a gridded, sheet beam klystron. This new klystron design avoids the CV2 losses of cathode pulsing because its cathode is not pulsed - it remains at a constant high voltage. Instead, the grid voltage is pulsed over a much smaller (6 kV) voltage range. This paper will describe DTI's progress in development of the electronics required to drive this new klystron, including a 500 kV multiplier power supply and grid modulator, a multi-concentric high voltage cable, which also acts as the pulse forming line, and an advanced, reentrant cable connection to the klystron itself. This design allows the klystron to be located adjacent to the beamline, and separated from the power electronics, improving RF efficiency, maintainability, and overall reliability.  
 
TUPKF053 New Waveguide-type HOM Damper for the ALS Storage Ring RF Cavities positron, focusing, cathode, impedance 1069
 
  • S. Kwiatkowski, K.M. Baptiste, J. Julian
    LBNL/ALS, Berkeley, California
  The ALS storage ring 500 MHz RF system uses two re-entrant accelerating cavities powered by a single 320kW PHILLIPS YK1305 klystron. During several years of initial operation, the RF cavities were not equipped with effective passive HOM damper systems. Longitudinal beam stability was achieved through cavity temperature control and the longitudinal feedback system (LFB), which was often operating at the edge of its capabilities. As a result, longitudinal beam stability was a significant operations issue at the ALS. During two consecutive shutdown periods (April 2002 and 2003) we installed E-type HOM dampers on the main and third harmonic cavities. These devices dramatically decreased the Q-values of the longitudinal anti-symmetric HOM modes. The next step is to damp the rest of the longitudinal HOM modes in the main cavities below the synchrotron radiation damping level. This will hopefully eliminate the need for the LFB and set the stage for a possible increase in beam current. The ?waveguide? type of HOM damper was the only option that didn?t significantly compromise the vacuum performance of the RF cavity. The design process and the results of the low level measurements of the new waveguide dampers are presented in this paper.  
 
TUPKF055 Space-charge-limited Magnetron Injection Guns for Gyroklystrons positron, focusing, impedance, booster 1072
 
  • W. Lawson
    Maryland University, College Park, Maryland
  We present the results of several space-charge-limited (SCL) magnetron injection gun (MIG) designs which are intended for use with a 500 kV, 500 A gyroklystron with accelerator applications. The design performances are compared to that of a temperature-limited (TL) gun that was constructed for the same application. The SCL designs yield similar values for beam quality, namely an axial velocity spread under 3% for an average perpendicular-to-parallel velocity ratio of 1.5. The peak electric fields and the cathode loadings of the SCL designs are somewhat higher than for the TL design. Three designs are described in this paper. In the first design the space-charge limit is achieved by recessing the emitter into the cathode. The other two designs have control electrodes to which a voltage can be applied to change the beam current independently of the beam voltage. One of these designs can accept a bias sufficiently high to cut off the current completely, so that a DC power supply with pulsed grid operation is possible. Details of all designs as well as a discussion of the advantages and disadvantages of the SCL designs as compared to the TL design will be given.  
 
TUPKF056 Multipacting in Crossed RF Fields near Cavity Equator positron, focusing, impedance, booster 1075
 
  • V.D. Shemelin
    Cornell University, Ithaca, New York
  Electric and magnetic fields near the cavity equator are presented in a form of expansions up to the third power of coordinates. Comparisons with numerical calculations made with the SLANS code for the TESLA and other cavity cells, as well as with the analytical solution for a spherical cavity are done. These fields are used for solution of equations of motion. It appears that for description of motion, the only main terms of the expansion are essential, but the value of coefficients for the electric field components depend on details of magnetic field behavior on the boundary. Equations of motion are solved for electrons moving in crossed RF fields near the cavity equator. Based on the analysis of these equations, general features of this kind of multipacting are obtained. Results are compared with simulations and experimental data. The "experimental" formulas for multipacting zones are explained and their dependence on the cavity geometries is shown. Developed approach allows evaluation of multipacting in a cavity without simulations but after an analysis of fields in the equatorial region. The fields can be computed by any code used for cavity calculation.  
 
TUPKF058 Test Results for the New 201.25 MHz Tetrode Power Amplifier at LANSCE positron, focusing, impedance, booster 1078
 
  • J.T.M. Lyles, S. Archuletta, J. Davis, L. Lopez, G. Roybal
    LANL/LANSCE, Los Alamos, New Mexico
  A new RF amplifier has been constructed for use as the intermediate power amplifier stage for the 201.25 MHz Alvarez DTL at LANSCE. It is part of a larger upgrade to replace the entire RF plant with a new generation of components. The new RF power system under development will enable increased peak power with higher duty factor. The first tank requires up to 400 kW of RF power. This can be satisfied using the TH781 tetrode in a THALES cavity amplifier. The same stage will be also used to drive a TH628 Diacrode? final power amplifier for each of the three remaining DTL tanks. In this application, it will only be required to deliver approximately 150 kW of peak power. Details of the system design, layout for DTL 1, and test results will be presented.  
 
TUPKF059 Simulation of Dark Currents in X-band Accelerator Structures positron, focusing, impedance, booster 1081
 
  • K.L.F. Bane, V.A. Dolgashev, G.V. Stupakov
    SLAC, Menlo Park, California
  In high gradient accelerator structures, such as those used in the main linac of the GLC/NLC, electrons are emitted spontaneously from the structure walls and then move under the influence of the rf fields. In this report we study the behavior of this "dark current" in X-band accelerator structures using a simple particle tracking program and also the particle-in-cell program MAGIC. We address questions such as what is the sensitivity to emission parameters, what fraction of dark current is trapped and reaches to the end of a structure, and what are the temporal, spatial, and spectral distributions of dark current as functions of accelerating gradient.  
 
TUPKF061 The SPEAR3 RF System positron, focusing, impedance, booster 1084
 
  • P.A. McIntosh, S. Allison, P. Bellomo, S. Hill, V. Pacak, S. Park, J.J. Sebek, D.W. Sprehn
    SLAC, Menlo Park, California
  SPEAR2 was upgraded in 2003, to a new 3rd Generation Light Source (3GLS) enabling users to take better advantage of almost 100x higher brightness and flux density over its predecessor SPEAR2. As part of the upgrade, the SPEAR2 RF system has been re-vamped from its original configuration of one 200 kW klystron feeding a single 358.5 MHz, 5-cell aluminum cavity; to a 1.2 MW klystron feeding four 476.3 MHz, HOM damped copper cavities. The system installation was completed in late November 2003 and the required accelerating voltage of 3.2 MV (800 kV/cavity) was very rapidly achieved soon after. This paper details the SPEAR3 RF system configuration and its new operating requirements, highlighting its installation and subsequent successful operation.  
 
TUPKF062 PEP-II RF System Operation and Performance positron, focusing, impedance, booster 1087
 
  • P.A. McIntosh, J. Browne, J.E. Dusatko, J.D. Fox, W.C. Ross, D. Teytelman, D. Van Winkle
    SLAC, Menlo Park, California
  The Low Energy Ring (LER) and High Energy Ring (HER) RF systems have operated now on PEP-II since July 1998 and have assisted in breaking all design luminosity records back in June 2002. Luminosity on PEP-II has steadily increased since then as a consequence of larger e+ and e- beam currents being accumulated. This has meant that the RF systems have inevitably been driven harder, not only to achieve these higher stored beam currents, but also to reliably keep the beams circulating whilst at the same time minimizing the number of aborts due to RF system faults. This paper details the current PEP-II RF system configurations for both rings, as well as future upgrade plans spanning the next 3-5 years. Limitations of the current RF system configurations are presented, highlighting improvement projects which will target specific areas within the RF systems to ensure that adequate operating overheads are maintained and reliable operation is assured.  
 
TUPKF063 Current Status of the Next Linear Collider X-band Klystron Development Program positron, klystron, impedance, booster 1090
 
  • D.W. Sprehn, G. Caryotakis, A.A. Haase, E.N. Jongewaard, C. Pearson
    SLAC, Menlo Park, California
  Klystrons capable of driving accelerator sections in the Next Linear Collider have been developed at SLAC during the last decade. In addition to fourteen 50 MW solenoid-focused devices and a 50 MW Periodic Permanent Magnet focused (PPM) klystron, a 500 kV 75 MW PPM klystron was tested in 1999 to 80 MW with 3-microsecond pulses, but very low duty. Subsequent 75 MW prototypes aimed for low-cost manufacture by employing reusable focusing structures external to the vacuum, similar to a solenoid electromagnet. During the PPM klystron development, several partners (CPI, EEV and Toshiba) have participated by constructing partial or complete PPM klystrons. After early failures during testing of the first two devices, SLAC has recently tested this design (XP3-3) to the full NLC specifications of 75 MW, 1.6 microseconds pulse length, and 120 Hz. This 14.4 kW operation came with a tube efficiency of 50%. The XP3 3 average and peak output power, together with the focusing method, arguably makes it the most advanced high power klystron ever built anywhere in the world. Design considerations and the latest testing results for these latest prototypes will be presented.  
 
TUPKF065 Comparison of Klystron and Inductive Output Tubes (IOT) Vacuum-electron Devices for RF Amplifier Service in Free-electron Laser positron, impedance, booster, focusing 1093
 
  • A. Zolfaghari, P. MacGibbon, W. North
    MIT/BLAC, Middleton, Massachusetts
  The MIT X-Ray Laser project, conceived to produce output in the 0.3 to 100 nanometer range, is based on a super-conducting 4-GEV linear accelerator, using 24 multi-cavity cryo-modules, each with its own dedicated RF amplifier, operating at 1.3 GHz. The continuous output of each amplifier is nominally 15 kW, with an optional repetitive pulse-modulation mode of 0.1 second pulse duration at one pulse per second. Although there are no fundamental restraints which preclude the consideration of any RF amplifier type, including solid-state or conventional triode or tetrode, the most appropriate current technology includes the Klystron and the IOT (Inductive Output Tube), also known by the CPI trade-name, Klystrode. The mechanisms by which the devices convert DC input power into RF output power are discussed. The devices are then compared with regard to availability (developmental or off-the-shelf), conversion efficiency, means of pulse-modulation, RF power gain, phase and amplitude stability (pushing factors), and acquisition and life-cycle costs.  
 
TUPKF066 34 Ghz, 45 MW Pulsed Magnicon: First Results impedance, booster, focusing, beamloading 1096
 
  • O.A. Nezhevenko, V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  • J.L. Hirshfield, M.A. LaPointe
    Yale University, Physics Department, New Haven, CT
  A high efficiency, high power magnicon at 34.272 GHz has been designed and built as a microwave source to develop RF technology for a future multi-TeV electron-positron linear collider. To develop this technology, this new RF source is being perfected for necessary tests of accelerating structures, RF pulse compressors, RF components, and to determine limits of breakdown and metal fatigue. After preliminary RF conditioning of only about 200000 pulses, the magnicon produced an output power of 10.5 MW in 0.25 microsecond pulses, with a gain of 54 dB. Slotted line measurements confirmed that the output was monochromatic to within a margin of at least 30 dB.  
 
TUPKF067 High Power Magnicons at Decimeter Wavelength for Muon and Electron-Positron Colliders impedance, booster, focusing, beamloading 1099
 
  • O.A. Nezhevenko, V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  • J.L. Hirshfield
    Yale University, Physics Department, New Haven, CT
  The CLIC drive linac requires pulsed RF amplifiers with a power of 50 MW at 937 MHz. In turn the muon collider requires 100 MW, 800 MHz RF amplifiers for the final stages of acceleration. In this paper conceptual designs of magnicons for these applications are presented. In addition to the typical magnicon advantages in power and efficiency, the designs offers substantially shorter tube length compared to either single- or multiple-beam klystrons.  
 
TUPKF068 JLAB Hurricane Recovery impedance, booster, focusing, beamloading 1102
 
  • A. Hutton, D. Arenius, F.J. Benesch, S. Chattopadhyay, E. Daly, V. Ganni, O. Garza, R. Kazimi, R. Lauze, L. Merminga, W. Merz, R. Nelson, W. Oren, M. Poelker, T. Powers, J.P. Preble, C. Reece, R.A. Rimmer, M. Spata, S. Suhring
    Jefferson Lab, Newport News, Virginia
  Hurricane Isabel, originally a Category 5 storm, arrived at Jefferson Lab on September 18 with winds of only 75 mph creating little direct damage to the infrastructure. However, electric power was lost for four days allowing the superconducting cryomodules to warm up and causing a total loss of the liquid helium. The subsequent recovery of the cryomodules and the impact of the considerable amount of opportunistic preventive maintenance provides important lessons for all accelerators complexes, not only those with superconducting elements. The details of how the recovery process was structured and the resulting improvement in accelerator availability will be discussed in detail.  
 
TUPKF072 Production and Performance of the CEBAF Upgrade Cryomodule Intermediate Prototypes impedance, booster, focusing, beamloading 1105
 
  • A-M. Valente, E. Daly, J.R. Delayen, M. Drury, R. Hicks, C. Hovater, J. Mammosser, H.L. Phillips, T. Powers, J.P. Preble, C. Reece, R.A. Rimmer, H. Wang
    Jefferson Lab, Newport News, Virginia
  • C. Thomas-Madec
    SOLEIL, Gif-sur-Yvette
  We have installed two new cryomodules, one in the nuclear physics accelerator (CEBAF) and the other in the Free Electron Laser (FEL) of Jefferson Lab. The new cryomodules consist of 7-cell cavities with the original CEBAF cell shape and were designed to deliver gradients of 70 MV/module. Several significant design innovations were demonstrated in these cryomodules. This paper describes the production procedures, the performance characteristics of these cavities in vertical tests, results of tests in the new cryomodule test facility (CMTF) as well as the commissioning in the CEBAF tunnel and FEL. Performances and limitations after installation in the accelerators are discussed in this paper along with improvements proposed for future cryomodules.  
 
TUPKF074 Niobium Thin Film Cavity Deposition by ECR Plasma impedance, booster, focusing, beamloading 1108
 
  • A-M. Valente, H.L. Phillips, H. Wang, A. Wu, G. Wu
    Jefferson Lab, Newport News, Virginia
  Nb/Cu technology for superconducting cavities has proven to be over the years a viable alternative to bulk niobium. Energetic vacuum deposition is a very unique alternative method to grow niobium thin film on copper. Single crystal growth of niobium on sapphire substrate has been achieved as well as good surface morphology of niobium on small copper samples. The design of a cavity deposition system is in development. This paper presents the exploratory studies of the influence of the deposition energy on the Nb thin film properties. Several possible venues to achieve Nb/Cu cavity deposition with this technique are also discussed along with the design of the cavity deposition setup under development.  
 
TUPKF075 Inductive Output Tubes for Particle Accelerators impedance, booster, focusing, beamloading 1111
 
  • H.P. Bohlen
    CPI, Palo Alto, California
  • E. Davies, P. Krzeminski, Y. Li, R.N. Tornoe
    CPI/EIMAC, San Carlos, California
  The Inductive Output Tube (IOT) is not widely used as an RF power source in particle accelerators yet, but this is about to change rapidly. One reason for this change is the IOT's "coming of age": almost twenty years of successful operation in television transmitters have lead to high refinement of IOT technology and proven reliability. The other reason is the fitness of the IOT to especially meet accelerator requirements: high efficiency, no need for power back-off to achieve fast feed-back regulation, and the possibility to pulse the RF without using a high-voltage modulator. Two classes of IOTs are available so far for application in particle accelerators. One of them consists of UHF external-cavity devices, frequency-tunable and producing output power levels up to 80 kW CW. The second class has been developed only recently. These are L-band IOTs with internal output cavities for 1.3 and 1.5 GHz, respectively, featuring output power levels between 15 and 30 kW CW. Extensive computer simulations have lead to the conclusion that even higher-power IOTs, such as a 300 kW peak-power, long-pulse L-band tube, are feasible.  
 
TUPKF076 Large Scale Production of 805-MHz Pulsed Klystrons for SNS impedance, booster, focusing, beamloading 1114
 
  • S. Lenci, E. Eisen
    CPI, Palo Alto, California
  The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The SNS will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. CPI is supporting the effort by providing 81 pulsed klystrons for the super-conducting portion of the accelerator. The primary output power requirements are 550 kW peak, 49.5 kW average at 805 MHz, with an electron beam-to-rf conversion efficiency of 65% and an rf gain of 50 dB. Through January 2004, 47 units have been factory-tested. Performance specifications, computer model predictions, operating results, and production statistics will be presented.  
 
TUPKF077 Test Results for a 10-MW, L-band, Multiple-beam Klystron for TESLA impedance, booster, focusing, beamloading 1117
 
  • E.L. Wright, A. Balkcum, H.P. Bohlen, M. Cattelino, L. Cox, E. Eisen, F. Friedlander, S. Lenci, A. Staprans, B. Stockwell, L. Zitelli
    CPI, Palo Alto, California
  • K. Eppley
    SAIC, Burlington, Massachusetts
  The VKL-8301 high-efficiency, multiple-beam klystron (MBK), has been developed for the DESY Tera Electron volt Superconducting Linear Accelerator (TESLA) in Hamburg, Germany. The first prototype is built and will be tested in March of 2004. The prototype has been designed for long-life operation by utilizing the benefits inherent in higher-order mode (HM) MBKs. The primary benefit of HM-MBKs is their ability to widely separate individual cathodes. One of the major obstacles to the success of this approach is the design of the off-axis electron beam focusing system, particularly when confined-flow focusing is desired. We will show simulated and measured data which demonstrates a solution to this problem. High power test results will also be shown.  
 
TUPKF078 High Current Superconducting Cavities at RHIC impedance, booster, focusing, beamloading 1120
 
  • R. Calaga, I. Ben-Zvi, Y. Zhao
    BNL, Upton, Long Island, New York
  • J. Sekutowicz
    Jefferson Lab, Newport News, Virginia
  A five-cell high current superconducting cavity for the electron cooling project at RHIC is under fabrication. Higher order modes (HOMs), one of main limiting factors for high current energy-recovery operation, are under investigation. Calculations of HOMs using time-domain methods in Mafia will be discussed and compared to calculations in the frequecy domain. A possible motivation towards a 2x2 superstructure using the current five-cell design will be discussed and results from Mafia will be presented. Beam breakup thresholds determined from numerical codes for the five-cell cavity as well as the superstructure will also be presented.  
 
TUPKF079 A Low Noise RF Source for RHIC impedance, booster, focusing, beamloading 1123
 
  • T. Hayes
    BNL, Upton, Long Island, New York
  The Relativistic Heavy Ion Collider requires a low noise rf source to ensure that beam lifetime during a store is not limited by the rf system. The beam is particularly sensitive to noise from power line harmonics. Additionally, the rf source must be flexible enough to handle the frequency jump required for rebucketing (transferring bunches from the acceleration to the storage rf systems). This paper will describe the design of a Direct Digital Synthesizer (DDS) based system that provides both the noise performance and the flexibility required.

Work performed under the auspices of the US Department of Energy

 
 
TUPKF080 Photoemission Properties of Lead impedance, laser, booster, focusing 1126
 
  • J. Smedley, T. Srinivasan-Rao, J. Warren
    BNL, Upton, Long Island, New York
  • R.S. Lefferts, A.R. Lipski
    SBUNSL, Stony Brook, New York
  • J. Sekutowicz
    Jefferson Lab, Newport News, Virginia
  There is significant interest in the possibility of building a super-conducting injector for high average current accelerator applications. One candidate for such a cavity design is superconducting lead. Such an injector would be made considerably simpler if it could be designed to use lead as the photocathode, eliminating the need for Cesiated materials in the injector. In this paper we present a study of the photoemission properties of lead at several UV wavelengths, including a study of the damage threshold of electroplated lead under laser cleaning. A quantum efficiency in excess of 0.1% has been achieved for a laser cleaned, electroplated lead sample with a laser wavelength of 193 nm.  
 
TUPLT001 Beam Dynamics in 100 MeV S-Band Linac for CANDLE impedance, laser, booster, focusing 1129
 
  • B. Grigoryan, V.M. Tsakanov
    CANDLE, Yerevan
  The report presents the results of the beam dynamics study in 100 MeV S-band linear accelerator foreseen as an injector for the CANDLE light source. An impact of the excited longitudinal and transverse wake fields on the particle energy spread and the beam transverse emittance are given.  
 
TUPLT002 The Small-gap Undulator Impedance Study impedance, laser, booster, focusing 1132
 
  • M. Ivanyan, V.M. Tsakanov
    CANDLE, Yerevan
  The small gap undulator vacuum chamber resistive impedance model is developed. The vacuum chamber is considered as equal-radii tubes with the different wall materials (stainless steel "copper" stainless steel). The complete impedance was calculated as a sum of tubes and transitions impedances. The modal expansion method for transition impedance calculation is presented.  
 
TUPLT003 Transfer Matrices for the Coupled Space Charge Dominated Six-dimensional Particle Motion impedance, laser, booster, focusing 1135
 
  • D. Kalantaryan, Y.L. Martirosyan
    CANDLE, Yerevan
  In this paper we present exact analytical solutions for the particle motion in the six-dimensional phase space taking into account the space charge forces of fully linear coupled beam. The transfer matrices for the typical elements of magnetic lattice, such as drifts, cavities, quadrupole and dipole magnets have been obtained. The symplectic transfer matrices are used to develop a tracking program for the coupled betatron and synchro-betatron motion that enables the simulation of the tilted beam effects in circular accelerators.  
 
TUPLT006 Simple Analytic Formulae for the Properties of Nonscaling FFAG Lattices impedance, laser, booster, focusing 1138
 
  • S.R. Koscielniak
    TRIUMF, Vancouver
  • M.K. Craddock
    UBC & TRIUMF, Vancouver, British Columbia
  A hallmark of the "non-scaling" FFAG lattices recently proposed for neutrino factories and muon colliders is that a wide range of momentum is compacted into a narrow radial band; dL/L is of order 10-3 for dp/p of order unity. This property is associated with the use of F0D0 or FDF triplet lattices in which the F magnet provides a reverse bend. In this paper simple analytic formulae for key lattice properties, such as orbit displacement and path length as a function of momentum, are derived from thin-element models. These confirm the parabolic dependence of path-length on momentum observed with standard orbit codes, reveal the factors which should be adjusted to minimize its variation, and form a useful starting point for the thick-element design (for which analytic formulae are also presented). A key result is that optimized doublet, F0D0 and triplet cells of equal length and phase advance have equal path-length performance. Finally, in the context of a 10-20 GeV/c muon ring, the thin-element formulae are compared against lattice optical properties computed for thick-element systems; the discrepancies are small overall, and most discernible for the triplet lattices.  
 
TUPLT007 The CERN-SPL Chopper Concept and Final Layout impedance, laser, booster, focusing 1141
 
  • F. Caspers, Y. Cuvet, J. Genest, M. Haase, M. Paoluzzi, A. Teixeira
    CERN, Geneva
  The fast chopper for the CERN SPL (Superconducting Proton Linac) consists of a double meander structure with a beta (v/c) value of 8 % printed on an alumina substrate for the deflecting plates. Each chopper unit is 50 cm long and housed in a quadrupole magnet surrounding the vacuum chamber. The deflecting plates are operated simultaneously in a dual mode, namely traveling wave mode for frequencies above about 10 MHz and as quasi electro-static deflectors below. The deflecting structures are water-cooled to handle heating from beam losses as well as from the deflecting signal. A detailed mechanical layout is presented including the tri-axial feeding and termination technique as well as a discussion of the drive amplifier  
 
TUPLT008 A Retrofit Technique for Kicker Beam-coupling Impedance Reduction laser, booster, focusing, beamloading 1144
 
  • F. Caspers, E.H.R. Gaxiola, T. Kroyer, M. Timmins, J.A. Uythoven
    CERN, Geneva
  • S.S. Kurennoy
    LANL/LANSCE, Los Alamos, New Mexico
  The reduction of the impedance of operational ferrite kicker structures may be desirable in order to avoid rebuilding such a device. Often resistively coated ceramic plates or tubes are installed for this purpose but at the expense of available aperture. Ceramic U-shaped profiles with a resistive coating fitting between the ellipse of the beam and the rectangular kicker aperture have been used to significantly reduce the impedance of the magnet, while having a limited effect on the available physical aperture Details of this method, constraints, measurements and simulation results as well as practical aspects are presented and discussed.  
 
TUPLT009 Trajectory Correction Studies for the CNGS Proton Beam Line laser, booster, focusing, beamloading 1147
 
  • M. Meddahi, W. Herr
    CERN, Geneva
  The performance of the proposed trajectory correction scheme for the CNGS proton beam line was checked with an advanced simulation program. It was first investigated whether the scheme will be sufficient, and if some correctors or monitors could be suppressed in order to reduce the cost. The correction scheme was in particular tested for the case of faulty correctors or monitors. Possible critical scenarios were identified, which may not be visible in a purely statistical analysis. This part of the analysis was largely based on the experience with trajectory and orbit correction problems encountered in the SPS and LEP. The simulation of the trajectory correction procedure was done using recently developed software.  
 
TUPLT010 Aperture and Stability Studies for the CNGS Proton Beam Line target, laser, booster, focusing 1150
 
  • M. Meddahi, W. Herr
    CERN, Geneva
  The knowledge of the beam stability at the CNGS target is of great importance, both for the neutrino yield and for target rod resistance against non-symmetric beam impact. Therefore, simulating expected imperfections of the beam line elements and possible injection errors into the CNGS proton beam line, the beam spot stability at the target was investigated. Moreover, the mechanical aperture of the CNGS proton beam line was simulated and the results confirmed that the aperture is tight but sufficient.  
 
TUPLT011 The LHC Lead Ion Injector Chain ion, target, laser, electron 1153
 
  • K. Schindl, A. Beuret, A. Blas, J. Borburgh, H. Burkhardt, C. Carli, M. Chanel, T. Fowler, M. Gourber-Pace, S. Hancock, C.E. Hill, M. Hourican, J.M. Jowett, K. Kahle, D. Kuchler, A.M. Lombardi, E. Mahner, D. Manglunki, M. Martini, S. Maury, F. Pedersen, U. Raich, C. Rossi, J.-P. Royer, R. Scrivens, L. Sermeus, E.N. Shaposhnikova, G. Tranquille, M. Vretenar, T. Zickler
    CERN, Geneva
  A sizeable part of the LHC physics programme foresees heavy ion (lead-lead) collisions with a design luminosity of 1027 cm-2 s-1. This will be achieved after an upgrade of the ion injector chain comprising Linac3, LEIR, PS and SPS machines. Each LHC ring will be filled in ~10 minutes with ~600 bunches, each of 7 107 Pb ions. Central to the scheme is the Low Energy Ion Ring (LEIR), which transforms long pulses from Linac3 to high-brilliance bunches by means of 6D multi-turn injection and accumulation via electron cooling. Major limitations along the chain, including space charge, intra-beam scattering, vacuum issues, and emittance preservation are highlighted. The conversion from LEAR (Low Energy Antiproton Ring) to LEIR includes new magnets and power converters, high-current electron cooling, broad-band RF cavities, upgraded beam diagnostics, and UHV vacuum equipment relying on beam scrubbing to achieve a few 10-12 mbar. Major hardware changes in Linac3 (Electron Cyclotron Resonance source, repetition rate, energy ramping cavity), PS (new injection hardware, elaborate RF gymnastics, stripping insertion), and SPS (100 MHz system) are described. An early beam scenario, using fewer bunches but the same bunch intensity to deliver a lower luminosity, reduces the work required for LHC ion operation in spring 2008.  
 
TUPLT012 Adjusting the IP Beta-functions in RHIC. ion, target, laser, electron 1156
 
  • W. Wittmer, F. Zimmermann
    CERN, Geneva
  • F.C. Pilat, V. Ptitsyn, J. Van Zeijts
    BNL, Upton, Long Island, New York
  The beta- functions at the IP can be adjusted without perturbation of other optics functions via several approaches. In this paper we describe a scheme based on a vector knob, which assigns fixed values to the different tuning quadrupoles and scales them by a common multiplier. The values for the knob vector were calculated for a lattice without any errors using MADX. Previous studies for the LHC have shown that this approach can meet the design goals. A specific feature of the RHIC lattice is the nested power supply system. To cope with the resulting problems a detailed response matrix analysis has been carried out and different sets of knobs were calculated and compared. The knobs are tested at RHIC during the 2004 run and preliminary results maybe discussed. Simultaneously a new approach to measure the beam sizes of both colliding beams at the IP, based on the tune ability provided by the knobs, was developed and tested.  
 
TUPLT013 Calculating LHC Tuning Knobs using Various Methods ion, target, laser, electron 1159
 
  • W. Wittmer, D. Schulte, F. Zimmermann
    CERN, Geneva
  By measuring and adjusting the beta-functions at the IP the luminosity is being optimized. In LEP this was done with the two closest doublet magnets. This approach is not applicable for the LHC due to the asymmetric lattice and common beam pipe through the triplet magnets. To control and change the beta-functions quadrupole groups situated on both sides further away from the IP have to be used where the two beams are already separated. The quadrupoles are excited in specific linear combinations, forming the so-called tuning knobs for the IP beta-functions. We compare the performance of such knobs calculated by different methods: (1) matching in MAD, (2) inversion of the re-sponse matrix and singular value decomposition inversion and conditioning and (3) conditioning the response matrix by multidimensional minimization using Hessian method.  
 
TUPLT014 Comparative Design Studies of a Super Buncher for the 72 MeV Injection Line of the PSI Main Cyclotron ion, target, laser, electron 1162
 
  • J.-Y. Raguin, A. Adelmann, M. Bopp, H. Fitze, M. Pedrozzi, P. Schmelzbach, P. Sigg
    PSI, Villigen
  The envisaged current upgrade from 2 to 3 mA of the PSI 590-MeV main cyclotron requires an increase of the global accelerating voltage of the 50-MHz cavities which leads to a nearly unacceptable RF requirement for the 150-MHz flattop cavity. In order to preserve the longitudinal acceptance and transmission of the machine while relaxing the high demands on the flattop system, it is conceivable to install a buncher in the 72-MeV injection line. To this end, normal-conducting 150-MHz half-wave resonators and 500-MHz two-gap drift-tube cavities have been designed and optimised for minimum input power and peak surface fields. The dependence of the RF properties (Q0, shunt impedances and peak fields) with beam apertures and gap voltages compatible with beam-dynamics requirements are presented.  
 
TUPLT015 The Bunch Compressor System for SIS18 at GSI target, laser, electron, booster 1165
 
  • P. Hülsmann, G. Hutter, W. Vinzenz
    GSI, Darmstadt
  For bunch compression down to pulse durations of 50 ns, a dedicated rf system is under development for the SIS12/18 heavy ion synchrotron upgrade and will be described in this paper. Due to space restrictions in SIS12/18 the rf system consists of very short cavities which provide a very large voltage gradient (50 kV/m) at a very low frequency of approximately 800 kHz and rf final stages which provide a short rise time. The only possibilty to meet the requirements is the application of a cavity heavily inductively loaded by metallic alloy (MA) ring cores. This new rf system will be a prototype for the advanced acceleration and compression system needed in SIS100, which is the most important part for the proposed International Acceleration Facility at GSI. In order to gain experience with different MA ring core materials two of the four compressor cavities are loaded differently, which gives us an opportunity to learn the operational advantages of both materials. It is expected that the experimental results will support the final judgement for the future rf system in SIS100.  
 
TUPLT016 Improved Performance of the Heavy Ion Storage Ring ESR target, laser, electron, booster 1168
 
  • M. Steck, K. Beckert, P. Beller, B. Franczak, B.  Franzke, F. Nolden
    GSI, Darmstadt
  The heavy ion storage ring ESR at GSI allows experiments with stable and radioactive heavy ions over a large range of energies. The energy range available for operation with completely stripped ions has recently been extended to energies as low as 3 MeV/u. Even for bare uranium such low energies can be provided by deceleration of the ions which are stripped to high charge states in a foil at energies of 300-400 MeV/u. After injection the beam is cooled and decelerated in an inverse synchrotron mode interspersed with electron cooling at an intermediate energy. At the lowest energy of 3 MeV/u some hundreds of thousands ions could be electron cooled after deceleration. At energies of 10-20 MeV/u physics experiments with stored and slowly extracted beam have been performed with some million decelerated cooled ions. The cooling of radioactive ions by a combination of stochastic pre-cooling and final electron cooling has been demonstrated. The hot fragment beam, which was injected at an energy of 400 MeV/u, was cooled in about 6 s to a quality useful for precision experiments.  
 
TUPLT017 Achievements of the High Current Beam Performance of the GSI Unilac target, laser, electron, booster 1171
 
  • W. Barth, L. Dahl, J. Glatz, L. Groening, S.G. Richter, S. Yaramishev
    GSI, Darmstadt
  The present GSI-accelerator complex is foreseen to serve for the future synchrotron SIS100 as an injector for up to 1012 U28+ particles/sec. The High Current Injector of the Unilac was successfully commissioned five years ago. An increase of more than two orders of magnitude in particle number for the heaviest elements in the SIS had to be gained. Since that time many different ion species were accelerated in routine operation. In 2001 a physics experiment used 2×109 Uranium ions per spill. In order to meet this request the MEVVA ion source provided for the first time in routine operation a high intense Uranium beam. The main purpose for the machine development program during the last two years was the enhancement of the intensity for Uranium beams. Different hardware measures and a huge investigation program in all Unilac-sections resulted in an increase of the uranium intensity by a factor of 7. The paper will focus on the measurements of beam quality, as beam emittance and bunch structure for Megawatt-Uranium beams. Additionally the proposed medium- and long-term hardware measures will be described, which should gain in the required uranium intensity to fill the SIS up to the space charge limit.  
 
TUPLT018 Layout of the Storage Ring Complex of the International Accelerator Facility for Research with Ions and Antiprotons at GSI laser, booster, focusing, beamloading 1174
 
  • P. Beller, K. Beckert, A. Dolinskii, B.  Franzke, F. Nolden, C. Peschke, M. Steck
    GSI, Darmstadt
  The storage ring complex of the new international accelerator facility consists of three different rings: the Collector Ring CR, the accumulator/decelerator ring RESR and the New Experimental Storage Ring NESR. The CR will serve for fast stochastic precooling of antiproton and rare isotope (RI) beams. Cooling time constants of about 100 ms for RI beams are envisaged. For experiments with RI beams the RESR serves as a decelerator ring. Precooled RI beams will be injected at 740 MeV/u and then decelerated to variable energies down to 100 MeV/u within about 1 s. The NESR will be the main instrument for nuclear and atomic physics. Besides experiments using an internal gas target, the NESR offers the possibility to collide circulating bunches of ions with electron bunches counter-propagating in a small 500 MeV electron storage ring. The physics program with antiprotons requires the accumulation of high intensity antiproton beams. The accumulation of 7×1010 antiprotons at 3 GeV per hour is foreseen. This will be accomplished by operating the RESR as an accumulator ring equipped with a stochastic cooling system. The NESR could then be used to decelerate antiprotons to 30 MeV.  
 
TUPLT019 Nonlinear Effects Studies for a Large Acceptance Collector Ring laser, booster, focusing, beamloading 1177
 
  • A. Dolinskii, K. Beckert, P. Beller, B.  Franzke, F. Nolden, M. Steck
    GSI, Darmstadt
  A large acceptance collector ring (CR) is designed for fast cooling of rare isotope and antiproton beams, which will be used for nuclear physics experiments in the frame of the new international accelerator facility recently proposed at GSI. This contribution describes the linear and non-linear optimisation used to derive a lattice solution with good dynamic behaviour simultaneously meeting the demands for very fast stochastic cooling for two optical modes (for rare isotope and antiproton beams). Effects due to non-linear field contributions of the magnet field in dipoles and quadrupoles are very critical in this ring. Using a single particle dynamics approach, the major magnetic non-linearities of the CR are studied. We discuss the particle dynamics of the dipole and quadrupole fringe fields and the their influence on the dynamic aperture and on the tune. Additionally, the CR will be operated at the transition energy (isochronous mode) for time of flight (TOF) mass spectrometery of short-lived radioactive ions. For this mode a specific correction scheme is required to reach a high degree of isochronism over a large acceptance.  
 
TUPLT020 High Intensity Uranium Operation in SIS18 laser, focusing, beamloading, antiproton 1180
 
  • P.J. Spiller, K. Blasche, P. Hülsmann, A. Krämer, H. Ramakers, H.R. Sprenger
    GSI, Darmstadt
  For the present experiment program and the planned international accelerator facility at GSI, the space charge limit of SIS18 for highly(4x1010) and intermediate (2.7x1011) charged uranium ions shall be reached within the next four years. Furthermore, measures to increase the repetition- and ramp rate up to 4 Hz with 10 T/s have been progressed. The present state of intensities per cycle and the limitations will be described. In connection with the planned enhancement of heavy ion intensities, protection, interlock and diagnostic systems, especially for the injection- and extraction devices have been prepared. Special attention is drawn on the insights which were achieved with respect to the operation at dynamic vacuum conditions. Results of R&D work with the goal to increase the intensity threshold and to improve the beam life time will be summarized. Furthermore, the specific upgrade program and schedule for the SIS18 booster mode will be presented.  
 
WEPLT100 Planar Electron Sources and the Electron Trap ELTRAP electron, antiproton, damping, vacuum 2080
 
  • M. Cavenago
    INFN/LNL, Legnaro, Padova
  • G. Bettega, F. Cavaliere, A. Illiberi, R. Pozzoli, M. Romé, L. Serafini
    INFN-Milano, Milano
  Filamentation and other space charge effects (both transverse and longitudinal) of intense electron beams, found for example in rf photoinjectors (beam energy 1 MeV, current 100 A), are easily studied in small voltage traps and drift channels (0.01-10 kV), keeping the same perveance order. A suitable Malmberg-Penning trap, named ELTRAP, installed and operated at the University of Milan, is briefly described; trap length ranges from 10 cm to 1 m; an uniform magnetic field confines electron radially. Several experimental regimes were investigated with the internal CW planar electron source: plasma, beam-plasma, beam, depending on the injection/extraction method chosen. Evolution of electron vortices and virtual cathode formation is documented; analogy with meteorologic and astrophysical plasma is discussed. Upgrading with an external laser pulsed electron source is in course. Larger planar sources are also under construction. (Main classification 4: Beam Dynamics and Electro-magnetic Fields; D03 High Intensity, Incoherent Instabilities, Space Charge, Halos, Cooling; Other classification 8: Low and Intermediate Energy Accelerators and Sources; T12 Beam Injection/Extraction and Transport; T02 Lepton sources)  
 
WEPLT101 On-line Mechanical Instabilities Measurements and Tuner Development in SC Low-beta Resonators electron, antiproton, vacuum, booster 2083
 
  • A. Facco, E. Bissiato, S. Canella, D. Carlucci, M. Lollo, F. Scarpa, D. Zenere
    INFN/LNL, Legnaro, Padova
  The use of high-Q and small rf bandwidth superconducting quarter wave resonators made of bulk niobium put severe requirements to the helium bath pressure stability to avoid cavity detuning. This is not always possible, and cavity detuning caused by slow pressure changes must be precisely followed by the cavity tuner. The LNL philosophy is based on mechanical damping of cavity vibrations and mechanical tuning in feedback for slow frequency compensation. The old-fashioned tuners installed in the ALPI linac had significant performance limitations. To replace them, we have designed, constructed and tested a new tuner which integrates the LNL system and control with the TRIUMF, backlash-free tuner leverage design. The new tuner is designed to compensate pressure changes up to 100 mbar/minute with a precision of 0.5 Hz, and it will be installed in the ALPI resonators. An upgraded prototype for future applications includes a piezoelectric actuator for fast tuning. Tuner characteristics and first test results will be presented. This system is extendable to other low-beta cavity types like superconducting rfqs.  
 
WEPLT102 Electron Cooling Experiments at HIMAC Synchrotron antiproton, vacuum, booster, target 2086
 
  • K. Noda, T. Furukawa, T. Honma, S. Shibuya, D. Tan, T. Uesugi
    NIRS, Chiba-shi
  • T. Iwashima
    AEC, Chiba
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  • S. Ninomiya
    RCNP, Osaka
  In the HIMAC synchrotron, the electron cooling experiments have been carried out since 2000 in order to develop new technologies in heavy-ion therapy and related research. Among of them, especially, the cool-stacking method has been studied to increase the intensity of heavy ions such as Fe and Ni in order to study the risk estimation of the radiation exposure in space. The simulation was carried out in order to optimize the stacking intensity under various the injection periods. In addition, the beam heating by the RF-KO and the clearing the secondary ion in the cooler were applied to avoid the instability occurred when the beam density became high. We will report the experiment results.  
 
WEPLT103 Radiation Damage in Magnets for Undulators at Low Temperature radiation, antiproton, vacuum, booster 2089
 
  • T. Bizen, X. Maréchal, T. Seike
    JASRI/SPring-8, Hyogo
  • Y. Asano
    JAERI/SPring-8, Hyogo
  • T. Hara, H. Kitamura, T. Tanaka
    RIKEN Spring-8 Harima, Hyogo
  • D.E. Kim, H.S. Lee
    PAL, Pohang
  Nd2Fe14B permanent magnets are used in many insertion devices for its good magnetic and mechanical properties. However, the radiation sensitivity of the magnets would be concern when they are used in a strong radiation environment. It is known that these magnets with very high coercivity show high resistance to radiation, though the substance for increasing the coercivity decrease the remanence. The coercivity and remanence of this magnet exhibit negative dependence against temperature, so it is expected to these magnets to show high remanence and high resistance to radiation at low temperature. The idea of using magnets at low temperature leads the new concept of the cryogenic undulators. In this report, the experimental results of the radiation damage of permanent magnets at low temperature are shown.  
 
WEPLT105 Beam-Beam Effects Measured Using Gated Monitors at KEKB radiation, antiproton, vacuum, electron 2092
 
  • T. Ieiri, Y. Funakoshi, T. Kawamoto, M. Masuzawa, M. Tawada, M. Tobiyama, S.S. Win
    KEK, Ibaraki
  KEKB is a multi-bunch, high-current, electron/positron collider for B meson physics. The two beams collide at one interaction point (IP) with a finite horizontal crossing angle and with a bunch-space of 6 to 8 ns. The luminosity of KEKB is the best in the world. The collision is performed by carefully adjusting a horizontal orbit bump of the electron beam at IP, which results in a horizontal offset to obtain the best luminosity. In order to investigate the asymmetric beam-beam effects, beam parameters of collision and non-collision bunches were compared using beam monitors capable of selecting a specific bunch in a bunch train. The beam-beam kick and the beam-beam tune-shift were obtained by the gated beam-position monitor and by the gated tune monitor. It was found that the horizontal offset was negligibly small in the case of a wide bunch-space of 48 ns. This result suggests that the horizontal offset is related to wake fields including electron-cloud effects.  
 
WEPLT106 Growth and Suppression Time of an Ion-related Vertical Instability radiation, antiproton, octupole, booster 2095
 
  • T. Miyajima, Y. Kobayashi, S. Nagahashi
    KEK, Ibaraki
  In the KEK Photon Factory electron storage ring, a vertical instability has been observed in a multi-bunch operation mode. The instability can be suppressed by octupole magnetic field in routine operation. Since the instability depends on a vacuum condition in the ring, it seems that it is an ion-related phenomenon. In order to study this instability, we measured the growth and the suppression time of it with the pulse octupole magnet system, which can produce the octupole field with rise and fall time of around 1.2msec. We obtained the result that the instability was grown slowly compared with to suppress it, and the growth time depended on the fill pattern of the bunch train and the beam current per bunch.  
 
WEPLT107 Nonlinear field Effects in the JPARC Main Ring radiation, sextupole, antiproton, proton 2098
 
  • A.Y. Molodojentsev, S. Machida, Y. Mori
    KEK, Ibaraki
  Main Ring (MR) of the Japanese Particle Accelerator Research Complex (JPARC) should provide acceleration of the high-intensity proton beam from the energy of 3GeV to 50 GeV. The expected beam intensity is 3.3·1014 ppp and the repetition rate is about 0.3 Hz. The imaginary transition lattice of the ring was adopted, which has the natural linear chromaticity about (-30) for both transverse phase planes. The expected momentum spread of the captured particles before the acceleration is less than 0.007. Two independent families of the chromatic sextupole magnets are use to eliminate the linear chromatic tune shift. This chromatic sextupole field nonlinearity will excite the normal 'octupole' resonances and will lead to the amplitude dependent tune shifts in both transverse phase planes. Additional sextupole magnets are planed to excite the third-order horizontal resonance, which will be used for the slow extraction. Incoherent tune shift of the low-energy proton beam is about (-0.16) so that some particles could cross nearest low-order resonances. Optimization of the 'bare' working point of MR at the injection energy has been performed to minimize the influence of the linear coupling and high-order coupling resonances. Excitation of the linear coupling resonance has been introduced by the realistic misalignment errors adopted for MR. The 'bare' working point during the slow extraction has been analyzed. The influence of the normal sextupole resonances on the large amplitude particle behavior at the scraper location has been studied including random sextupole field component of the MR bending magnets. Realistic distortion of the ideal ring super-periodicity by the injection kicker magnets has been included in the tracking procedure for the on- and off-momentum particles. Finally, correction schemes have been considered for most dangerous resonances around the optimized 'bare' working point. The space-charge effects of the proton beam have not been included in this study.  
 
WEPLT108 Diffusion caused by Beam-beam Interactions with Couplings radiation, sextupole, antiproton, proton 2101
 
  • K. Ohmi, S. Kamada, K. Oide, M. Tawada
    KEK, Ibaraki
  A system of colliding two beams is strong nonlinear in multi-dimension. In such a system, a symplectic diffusion called Arnold diffusion occurs, with the result that the beams are enlarged and the luminosity is degraded in circular colliders. We discuss the diffusion seen in beam-beam inetraction at a circular accelerator, especially finite crossing angle and/or x-y coupling errors enhance the diffusion.  
 
WEPLT109 Simulation of Ep Instability for a Coasting Proton Beam in Circular Accelerators radiation, sextupole, antiproton, booster 2104
 
  • K. Ohmi, T. Toyama
    KEK, Ibaraki
  • G. Rumolo
    GSI, Darmstadt
  ep instability is discussed for a coasting beam operation of J-PARC 50 GeV Main Ring. Our previous study (PAC2003) was focussed only ionization electron. We now take into account electrons created at the chamber wall due to proton loss and secondary emission with higher yield than ionization.  
 
WEPLT110 Specific Beam Dynamics in Super-bunch Acceleration radiation, sextupole, antiproton, booster 2107
 
  • Y. Shimosaki, E. Nakamura, K. Takayama, T. Toyama
    KEK, Ibaraki
  • K. Horioka, M. Nakajima
    TIT, Yokohama
  • K. Koseki
    GUAS/AS, Ibaraki
  • K. Torikai
    Kyushu University, Fukuoka
  • M. Watanabe
    RIKEN, Saitama
  Proof-of-principle experiments on the induction synchrotron concept using the KEK 12-GeV PS makes progress, in which RF bunches and a super-bunch will be accelerated with a long step voltage generated in the induction accelerating gaps. In order to give a guide for super-bunch acceleration, the beam stabilities against a droop and a fluctuation of the accelerating voltage have been examined by using a simulation. The droop voltage gives an additional focusing or defocusing force in the longitudinal direction, which leads the mismatching beyond the transition energy. Furthermore, the extremely slow fluctuation of the accelerating voltage causes a lowest-order resonance near the transition. These induce a serious emittance blow-up in the longitudinal, so that the compensating manners will be presented. Moreover, the other issues such as head-tail instability and intra beam scattering will be discussed.  
 
WEPLT113 Development of New Hydrostatic Levelling Equipment for Large Next Generation Accelerator radiation, sextupole, antiproton, booster 2110
 
  • S. Takeda
    KEK, Ibaraki
  The Hydrostatic Levelling Systems (HLS) are installed and commissioned in many laboratories. We have developed a new type hydrostatic levelling equipment for the large future accelerator. The designing points are as followings: (1) use of half filled water level sensor instead of the usual full filled level sensor, (2) the capacitive sensor is supported by an invar rod and (3) use of digitized signal transfer system. These three points are very important factor to apply the leveling system to large next generation accelerator in order to obtain good temperature stability and being free from the environmental electronic noises. We have obtained a typical resolution of the equipment as 0.3 micron-meter, though usual HLS shows the value ten times as much. We are going to show a detailed report about the system including data obtained.  
 
WEPLT114 Field Measurements in the AGS Warm Snake radiation, sextupole, antiproton, booster 2113
 
  • J. Takano, M. Okamura
    RIKEN, Saitama
  • R. Alforque, R. Belkin, G. Ganetis, A.K. Jain, W.W. MacKay, T. Roser, R. Thomas, J. Tuozzolo
    BNL, Upton, Long Island, New York
  • T. Hattori
    RLNR, Tokyo
  A new warm snake has been produced for avoiding the transverse coupling resonance in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). The warm snake is the world?s first normal conducting helical dipole partial snake which has a double pitch structure to allow spin rotation with no net beam offset or deflection with a single magnet. The warm snake is 2.6m long, and has a field of 1.5 Tesla for a 9 degrees spin rotation. The pitches, current density, and shims were optimized by using OPERA_3D / TOSCA. The magnetic field harmonics have been measured using a system of 51 mm long, 34 mm radius tangential coils. The axial variation of the dipole field angle agrees very well with the calculations, indicating no significant construction errors. However, the measured transfer function shows a discrepancy of 4% which may be caused by BH-curve differences, deformation of the iron and packing factor of the laminations. To correct the beam trajectory the operating current was adjusted and shims were installed on the end plates. These optimization studies, and comparison with measurements, will be shown.  
 
WEPLT115 A Study of Transverse Resonance Crossing in FFAG radiation, sextupole, antiproton, resonance 2116
 
  • M. Aiba
    University of Tokyo, Tokyo
  • S. Machida, Y. Mori
    KEK, Ibaraki
  A study of "resonance crossing" in FFAG accelerator is described in this paper. A deviation of FFAG guiding field in actual magnet breaks zero chromaticity condition, and tunes cross resonance while acceleration. In order to avoid a critical beam loss or emittance growth, nominal tune should be chosen so as not to cross low-order resonances. However, crossing higher order resonance can be critical and that depends on the parameters such as crossing speed, excitation magnitude and initial beam emittance. We will present analytical model and simulation study in various parameter space.  
 
WEPLT116 Lattice Design and Cooling Simulation at S-LSR radiation, sextupole, antiproton, resonance 2119
 
  • T. Shirai, H. Fadil, S. Fujimoto, M. Ikegami, A. Noda, M. Tanabe, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • T. Fujimoto, H. Fujiwara, K. Noda, S. Shibuya, T. Takeuchi
    NIRS, Chiba-shi
  • M. Grieser
    MPI-K, Heidelberg
  • H. Okamoto, Y. Yuri
    HU/AdSM, Higashi-Hiroshima
  • E. Syresin
    JINR, Dubna, Moscow Region
  A compact ion cooler ring, S-LSR is under construction in Kyoto University. The circumference is 22.557 m and the maximum magnetic rigidity is 1 Tm. One of the important roles of S-LSR is a test bed to examine the lowest temperature limit of the ion beams using cooling techniques. The ultimate case is a crystalline one. The ring optics of S-LSR has a high super periodicity and a low phase advance to reduce the beam heating from the lattice structure. S-LSR has an electron beam cooling device and a laser cooling system for Mg. The simulation results show the possible limit of the ion beam temperature and the dependence on the operating betatron tunes.  
 
WEPLT117 Design of a Third Harmonic Superconducting RF System at PLS radiation, sextupole, antiproton, resonance 2122
 
  • E.-S. Kim, M.-H. Chun, H.-G. Kim, K.-R. Kim, I.-S. Park, Y.-U. Sohn, J.S. Yang
    PAL, Pohang
  • J.-K. Ahn, J.-S. Cho
    Pusan National University, Pusan
  A superconducting third harmonic rf system has been designed in the PLS to raise beam lifetime. Expected beam lifetimes verse beam emittance and operational beam current are presented. A multibunch multiparticle tracking simulation is performed to investigate energy spread, bunch-lengthening and beam instabilities due to the rf cavities. The parameters of the designed rf cavity, designed cryogenic system and estimation of heat load are also presented.  
 
THPLT093 Particle-in-cell Numerical Simulations of Particle Dynamics in Beams and ECR Sources feedback, antiproton, emittance, ion 2709
 
  • G. Shirkov, V. Alexandrov, V. Shevtsov
    JINR/PPL, Dubna, Moscow Region
  A summary of recent development of physical and mathematical basements and the first version of computer code library based on the particle-in-cell method are presented. The code library is aimed for the three-dimensional (3D) simulation of the ECR plasma and ion production in the ECR ion source. The particle-in-cell (finite particle) method is one of the most powerful methods for the numerical simulation of multicomponent ECR plasma and electron-ion beams. This method allows studying the detailed characteristics of plasma, taking into account the distribution functions of particles (spatial, velocity and energy distributions), real self and external fields, particle-particle interactions and many other effects. This technique promises to provide very precise numerical simulations and optimizations of ECR ion sources. The first results of simulations of ECR source plasma are presented. It has been shown that a complete and adequate description of ECR plasma requires the full-scale 3D model and computer codes. This is out of frames of existed project and could be an aim of some addition investigations.  
 
THPLT094 Ordered Ion Beam in Storage Rings feedback, ion, antiproton, emittance 2712
 
  • A. Smirnov, I.N. Meshkov, A.O. Sidorin, E. Syresin, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  • T. Katayama
    CNS, Saitama
  • H. Tsutsui
    SHI, Tokyo
  The using of crystalline ion beams can increase of the luminosity in the collider and in experiments with targets for investigation of rare radioactive isotopes. The ordered state of circulating ion beams was observed experimentally at several storage rings. In this report a new criteria of the beam orderliness are derived and verified with BETACOOL code with using molecular dynamics technique. The sudden reduction of momentum spread observed on a few rings is described with this code. The simulation shows a good agreement with the experimental results. The code has then been used to calculate characteristics of the ordered state of ion beams for ion rings which will have experimental programs for the study of crystalline beams. A new strategy of the cooling process is proposed which permits to increase the linear density of the ordered ion beam.  
 
THPLT095 Nuclotron Extracted Beam Spill Control ion, antiproton, emittance, feedback 2715
 
  • V. Volkov, V. Andreev, E. Frolov, V. Karpinsky, A. Kirichenko, A.D. Kovalenko, V.A. Mikhaylov, S. Romanov, B. Vasilishin, A. Volnov
    JINR, Dubna, Moscow Region
  The first experiments with the Nuclotron Beam Slow Extraction System (BES) were carried out in December 1999. After the BES commissioning, the development of the system was continued together with experiments on relativistic nuclear physics. To realize the constant-current-beam or the constant-time-length spill and to suppress the low frequency spill structure in the range up to several hundred hertz, a spill control subsystem was designed and put into operation. It consists of a feedback loop in parallel with a feed-forward control. In the feedback loop the extracted particle flux is measured with beam current monitor and is compared with the request flux. The resulting error signal is fed into a feedback controller. The controller is an analog unit in which integration, differentiation and gain can be adjusted separately. The output control signal is added to the extraction quadrupoles power supply pattern generated by the corresponding function generator. The beam spill control subsystem has been improved in stages since its commissioning in 2000. The beam spill duration of more than 10s and the beam spill uniformity of about 0.9 were achieved in recent Nuclotron runs.  
 
THPLT099 The Analysis of the Electron Beam Scanning Method for the Beam Profile Monitoring. antiproton, emittance, feedback, cyclotron 2718
 
  • D.A. Liakin
    ITEP, Moscow
  The method of the beam profile monitoring with scanning electron beam is analyzed. Simulation model of the ion/electron beam interaction is presented and some simulation results are shown. In the report the estimation of overall performance characteristics of this method such as sensitivity, spatial resolution, frequency bandwidth etc. are given.  
 
THPLT100 Development of a Permanent Magnet Residual Gas Profile Monitor With Fast Readout antiproton, emittance, feedback, cyclotron 2721
 
  • D.A. Liakin, S.V. Barabin, V. Skachkov
    ITEP, Moscow
  • P. Forck, T. Giacomini
    GSI, Darmstadt
  • A. Vetrov
    MSU, Moscow
  The beam profile measurement at modern ion synchrotrons and storage rings require high timing performances on a turn-by-turn basis. From the other hand, high spatial resolutions are very desirable for cold beams. We are developing a residual gas monitor to cover the wide range of beam currents and transversal distributions of particles. It supplies the needed high-resolution and high-speed tools for beam profiling. The new residual gas monitor, will operate on secondary electrons whose trajectories are localized within 0.1 mm filaments. The required magnetic field of 100 mT will be excited by a permanent magnet. In the fast turn-by-turn mode the beam profile will be read out with a resolution of 1 mm by a 100-channel photodiode-amplifier-digitizer. The high resolution mode of 0.1 mm is provided by a CCD camera with upstream MCP-phosphor screen assembly. In this paper the first results of the photodiode-digitizer device testing, the compact mechanical design features and simulation results of the permanent magnet device are presented.  
 
THPLT102 Characteristics of Sealed-off Electron Gun with Wide Beam gun, antiproton, emittance, feedback 2724
 
  • V.M. Pirozhenko
    MRTI RAS, Moscow
  • A.N. Korolev, K.G. Simonov
    ISTOK, Moscow Region
  Compact sealed-off electron gun is a new promising type of devices. The gun generates wide beam of electrons with energy up to 200 keV and high peak power in 2-microsecond pulses. The beam is extracted to the atmosphere or a gas through the foil being uniformly distributed over the area of exposure. The gun contains the long ribbon cathode of oxide type, the electrodes for forming required distribution of the beam, the output window with 20-micron titanium foil, the high-voltage ceramic insulator, and the vacuum casing of rectangular shape. The gun is applied in the radiation technology system intended for the treatment of continuously moving tapes with 300 mm width. The gun design provides 10% uniformity of the radiation dose on the tape width.  
 
THPLT106 Measurement of Beam Polarization in VEPP-3 Storage Ring using Internal Target-based Moeller Polarimeter gun, antiproton, polarization, emittance 2727
 
  • A.V. Grigoriev, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.I. Mishnev, S.A. Nikitin, D.M. Nikolenko, I.A. Rachek, Y.V. Shestakov, D.K. Toporkov, V.N. Zhilich
    BINP SB RAS, Novosibirsk
  A method for beam polarization measurement in a storage ring has been for the first time developed and applied based on measuring the asymmetry in scattering of polarized beam electrons on the internal polarized gas jet target. Using this method we have studied the polarization in VEPP-3 booster storage ring. VEPP-3 is the source of polarized beams for VEPP-4M electron-positron collider in the planned experiment on high-precision mass measurement of tau-lepton near the production threshold of the latter (1777 MeV). Radiative polarization of beams obtained in VEPP-3 is used for absolute calibration of particle energy by the resonant depolarization technique after injection into VEPP-4M ring. The polarimeter design is described. Results of polarization measurements performed in 60 MeV range of VEPP-3 energy contiguous from above to tau-lepton production threshold are presented and discussed. The depolarizing influence of the integer machine spin resonance (1763 MeV) as well as of the combination spin resonances with the betatron frequencies are found to be significant.  
 
THPLT107 VEPP-4M Optical Beam Profile Monitor with a One-turn Temporal Resolution gun, antiproton, polarization, emittance 2730
 
  • O.I. Meshkov, V.F. Gurko, A.D. Khilchenko, V. Kiselev, N.Y. Muchnoi, N.A. Selivanov, V.V. Smaluk, A.N. Zhuravlev, P.V. Zubarev
    BINP SB RAS, Novosibirsk
  The transverse beam profile monitor based on Hamamatsu multi-anode photomultiplier with 16 anode strips is used at the VEPP-4M collider. The monitor is applied to study turn-to-turn dynamics of the transverse beam profile during 131 000 turns. The device provides a permanent measurement of synchrotron and betatron frequencies as well.  
 
THPLT108 The Study of the Beam TAILS with the Optical Coronagraph gun, antiproton, polarization, emittance 2733
 
  • O.I. Meshkov, M.G. Fedotov, E.V. Kremyanskaya, E. Levichev, N.Y. Muchnoi, Yu.A. Pakhotin, N.A. Selivanov, A.N. Zhuravlev
    BINP SB RAS, Novosibirsk
  Optical white-light Lyot coronograph is applied at the VEPP-4M collider to study the "tails" of the transverse beam profile. The device is used for investigation of the beam-beam effects.  
 
THPLT109 The Upgraded Optical Diagnostic of the VEPP-4M Collider gun, antiproton, polarization, emittance 2736
 
  • O.I. Meshkov, M.G. Fedotov, V.F. Gurko, A.D. Khilchenko, N.Y. Muchnoi, Yu.A. Pakhotin, N.A. Selivanov, A.N. Zhuravlev, E.I. Zinin, P.V. Zubarev
    BINP SB RAS, Novosibirsk
  The upgraded optical diagnostic of the VEPP-4M collider is described. The system abilities are improved sufficiently in comparing with the previous version. Now the diagnostic supplies the data about an electron/positron beam transversal and longitudinal size, shape and position. It is applied to study the electron beam "tails" and turn-to-turn beam profile dynamics. The system is used to tune of the beam pass-by from the VEPP-3 booster to the VEPP-4M collider and provides the permanent measurements of the synchrotron and betatron frequencies.  
 
THPLT110 Modelling of Accelerating Structures with Finite-difference Time-domain Method gun, antiproton, polarization, emittance 2739
 
  • E.V. Pickulin, V.N. Malyshev
    LETI, Saint-Petersburg
  • S.A. Silaev, Y.A. Svistunov
    NIIEFA, St. Petersburg
  A finite-difference time-domain (FDTD) method is very popular for electromagnetic field modeling. The practical interest in the method is the ability to calculate fields in time domain at any time point in the accelerating structure. That is to say the FDTD method is able to model transient process taking into account the peculiarity of RF power input device. A FDTD approach for modeling of alternate phase focusing structure is presented in this paper. The modeling of lossy metals is a problem in classical formulation of FDTD method. This matter is investigated and one of the solutions is presented in this paper. There are some problems of signal processing when using time-domain method for resonant structure modeling. The matters of mode determination are also investigated and presented in this paper. The simulation results are compared with experimental data.  
 
THPLT111 An Accelerator-based Thermal Neutron Source for BNCT Application gun, antiproton, polarization, emittance 2742
 
  • A. Makhankov, A. Gervash, R. Giniyatulin, I. Mazul, M. Rumyantsev
    NIIEFA, St. Petersburg
  • J. Esposito, L.B. Tecchio
    INFN/LNL, Legnaro, Padova
  • V. Khripunov
    RRC Kurchatov Institute, Moscow
  An accelerator-based thermal neutron source, aimed at the BNCT treatment of skin melanoma is in construction at the INFN-LNL in the framework of SPES project. The BNCT device exploit the intense proton beam provided by a 5 MeV, 30 mA RFQ that represent the first accelerating step of the SPES exotic nuclei production beam facility. Neutrons are generated by 9Be(p,n)9B nuclear reaction in a high power (150 kW) Beryllium target. The operational condition of the Beryllium converter is close to the condition of Be-armoured components in fusion reactors. The main difference consists in the necessity of limitation of structural materials amount used in the design in order to meet therapeutic irradiation requirements. Two possible design of neutron converter are developed: one with saddle block tiles brazed to CuCrZr tubes and another one with Be target made from solid Be block. Results of R&D works on the development of water cooled Be target for converter are presented, including data on selected materials, technological trials and mockups high heat flux testing.  
 
THPLT112 Methods and Instrumentation for Measurement of Low Ion Beam Currents at Cryring gun, antiproton, polarization, emittance 2745
 
  • A. Paal, A. Källberg, A. Simonsson
    MSL, Stockholm
  • J. Dietrich, I. Mohos
    FZJ/IKP, Jülich
  In many CRYRING experiments an accurate measurement of the circulating ion beam current is essential for determination of e.g. absolute cross sections. However, the current produced from the ion source can be very low. Furthermore, when surface barrier detectors are used, for example in the merged electron-ion beam experiments, the current has to be kept low to avoid saturation. With new electronics, using an Integrating Current Transformer with 5 V/A sensitivity, the current resolution of the Bergoz Beam Charge Monitor (BCM) has been increased to below 1 nA for bunched beams. The sum signal of the capacitive pick-up located at the farthest point from the RF-system is integrated by a second gated integrator. The RMS resolution is about 100 pA. To measure the intensity of coasting beams neutral particle detectors and a residual-gas beam profile monitor are used, calibrated with the BCM output during 20-100 ms after acceleration. The micro-channel plate detectors can handle a few Mcps count rate with a maximum 1 cps dark count rate. Presently a 50 Mcps secondary electron multiplier is being tested as a neutral particle monitor, having a maximum dark count rate of 0.05 cps  
 
THPLT113 Conceptual Design of a Microwave Confocal Resonator Pick-up gun, antiproton, polarization, emittance 2747
 
  • V.G. Ziemann, A. Ferrari, T. Lofnes
    TSL, Uppsala
  • F. Caspers, I. Syratchev
    CERN, Geneva
  A confocal resonator may be used as a pick-up for frequencies in the multi-GHz region. In this report we discuss the design by analytical and numerical methods of such a device. Furthermore we discuss engineering issues such as the damping of unwanted modes, shielding of image fields and manufacturing tolerances. Such a device can be used both as pick-up and kicker where the actual structure is several wavelengths away from the beam in the transverse direction. It is intended for highly relativistic beams and does not require changing particle trajectory as opposed to a diagnostic wiggler.  
 
THPLT114 A New Mono-energetic Neutron Beam Facility in the 20-180 MeV Range gun, antiproton, polarization, emittance 2750
 
  • V.G. Ziemann, L.-O. Andersson, T. Bergmark, O. Bystrom, A. Bäcklund, H. Calen, L. Einarsson, C. Ekström, J. Fransson, K.J. Gajewski, N. Haag, T. Hartman, E. Hellbeck, T. Johansen, O. Jonsson, B. Lundström, R.P. Peterson, L. Pettersson, A. Prokofiev, D. Reistad, P.-U. Renberg, R. Wedberg, D. Wessman, L. Westerberg, D. van Rooyen
    TSL, Uppsala
  • J. Blomgren, S. Pomp, U. Tippawan, M. Österlund
    INF, Uppsala
  Recent interest in nuclear applications involving neutrons, like ransmutation of nuclear waste, fast-neutron cancer therapy, dose to personnel in aviation and electronics failures due to cosmic-ray neutrons, motivate the development of a facility producing intense mono-energetic neutron beams. At The Svedberg laboratory (TSL), Uppsala, Sweden, we have developed such a facility by utilizing the existing cyclotron and inserting a flexible Lithium target in a rebuilt beam line. The new facility can operate at unsurpassed quasi-monoenergetic neutron intensities and provides large flexibility of the neutron beam properties, like diameter and shape.  
 
THPLT122 The Energy Deposition Profile of 0.1-3.0 MeV Electrons in NaCl gun, antiproton, polarization, emittance 2753
 
  • V.V. Gann
    NSC/KIPT, Kharkov
  • A.V. Sugonyako, D.I. Vainshtein, H.W. den Hartog
    RUG, Groningen
  An analysis is presented of existing experimental and theoretical data of energy loss profiles and energy deposition in thick targets irradiated with MeV-energy electrons. A simple approximate calculation is proposed for the energy deposition profile of a perpendicular beam of 0.1-3 MeV electrons in matter. The results obtained with this method are in agreement with existing calculated and measured energy absorption profiles for a variety of materials. It will be shown that the build-up phenomenon has a significant effect on the energy deposition profile in thick samples. A systematic experimental investigation of the energy deposition profile of 0.5 MeV electrons in 0.2 - 0.8 mm thick NaCl platelets has been carried out. The distribution of the absorbed dose was determined with differential scanning calorimetry method by measuring either the latent heat of melting of the radiation-induced Na-precipitates or the stored energy.  
 
THPLT123 Coupling Coefficients in the Inhomogeneous Cavity Chain gun, antiproton, polarization, emittance 2756
 
  • K. Kramarenko, M.I. Ayzatskiy
    NSC/KIPT, Kharkov
  In this paper a mathematical method on the base of a rigorous electrodynamic approach for description of inhomogeneous chain of cylindrical cavities is presented. The form of the obtained for chosen amplitudes set of equations is similar to the set of equations that describe the simple coupled circuit chain. As the cavity have the infinite number of resonant frequencies, to obtain the coupling coefficients one have to solve additional infinite set of linear equations with coefficients that depend on the frequency. Using the developed method in the case of inhomogeneous cavity chain we calculated the dependence of the coupling coefficients on frequency and geometrical sizes with taking into account the 'long-range' coupling.  
 
THPLT124 Simulation Technique for Study of Transient Self-consistent Beam Dynamics in RF Linacs gun, antiproton, polarization, emittance 2759
 
  • V.V. Mytrochenko, A. Opanasenko
    NSC/KIPT, Kharkov
  The report describes a simulation technique for study of unsteady self-consistent dynamics of charged particles in resonant linacs. The technique allows simulating the linacs that consist of resonant cavities and traveling wave sections. The proposed approach is based on unsteady theories of excitation of resonant cavities and waveguides by a beam of charged particles and RF feeders. The theory of waveguide excitation is generalized to the case of spatially inhomogeneous traveling wave structures. The system of self-consistent differential equations for fields and motion of particles is integrated over time and space. The SUPERFISH code is used to evaluate characteristics of the axially symmetrical cavities and traveling wave sections. The PARMELA code is applied to simulate motion of the particles at each time step of the integration. In such a way the fields and beam characteristics in the axially symmetrical accelerating structures can be obtained for transient and steady state operation. Description of the algorithm and results of its validation are presented.  
 
THPLT127 Beam Diagnostics Systems for the Diamond Synchrotron Light Source gun, antiproton, polarization, electron 2762
 
  • G. Rehm, A.F.D. Morgan, C. Thomas
    Diamond, Oxfordshire
  We present an overview of the diagnostics systems that will be implemented at the Diamond synchrotron light source. The aim of this paper is to give a complete picture of the systems to measure the quality of the electron beam from the injector through to the storage ring. We will show how we intend to measure the dimensions, the position and the time structure of the electron bunches. In addition, the instrumentation to measure the charge, the current and the emittance of the electron beam will be described. Finally, systems to provide accurate measurement of electron losses and the injection efficiency will be detailed.  
 
THPLT129 Ion Chambers for Monitoring the NuMI Beam at FNAL gun, antiproton, proton, polarization 2765
 
  • S.E. Kopp, D. Indurthy, R. Keisler, S. Mendoza, Z. Pavlovich, M. Proga, R.M. Zwaska
    The University of Texas at Austin, Austin, Texas
  • M. Diwan, B. Viren
    BNL, Upton, Long Island, New York
  • A.R. Erwin, H.P. Ping, C.V. Velisaris
    UW-Madison/PD, Madison
  • D. Harris, A. Marchionni, J. Morfin
    Fermilab, Batavia, Illinois
  • J. McDonald, D. Naples, D. Northacker
    University of Pittsburgh, Pittsburgh, Pennsylvania
  We summarize selected instrumentation under construction for the NuMI neutrino beam facility at Fermilab. An array of foil secondary emission monitors (SEM's) will measure the 120GeV proton beam position, profile and halo at 10 stations along the transport to the NuMI target. The final two foil SEM's align the proton beam to within 50 microns on target. These are capable of withstanding the 400kW proton beam and causing <5·10-6 beam loss. Further instrumentation includes four stations of ionization chambers located downstream of the decay volume, one upstream and three downstream of the beam dump. The latter three monitor the tertiary muon beam, the first monitors the remnant hadron beam. The ion chamber arrays align the proton beam to 14microRadian and the neutrino beam to within 50 microRadian, as well as monitoring flux to better than 1%. The ion chambers are designed to withstand the ~1GRad doses and 109 particle/cm2/spill fluxes anticipated during NuMI beam operations. Beam tests and R&D efforts are discussed.  
 
THPLT130 Synchronization of the Fermilab Booster and Main Injector for Multiple Batch Injection gun, proton, polarization, electron 2768
 
  • R.M. Zwaska, S.E. Kopp
    The University of Texas at Austin, Austin, Texas
  • W. Pellico, R.C. Webber
    Fermilab, Batavia, Illinois
  To date, the 120 GeV Fermilab Main Injector accelerator has accelerated a single batch of protons from the 8 GeV rapid-cycling Booster synchrotron for production of antiprotons for Run II. In the future, the Main Injector must accelerate 6 or more Booster batches simultaneously; the first will be extracted to the antiproton source, while the remaining are extracted for the NuMI/MINOS neutrino experiment. Performing this multi-batch operation while avoiding unacceptable radioactivation of the beamlines requires a previously unnecessary synchronization between the accelerators. We describe a mechanism and present results of advancing or retarding the longitudinal progress of the Booster beam by active feedback radial manipulation of the beam during the acceleration period.  
 
THPLT133 Simulation of RF Control of a Superconducting Linac for Relativistic Particles gun, proton, polarization, electron 2771
 
  • M. Huening, P. Bauer, G.W. Foster
    Fermilab, Batavia, Illinois
  We present a code to simulate the rf field and field control in a superconducting linac for relativistic heavy particles. In such a linac the field stability is strongly influenced by the longitudinal beam dynamics. So the code has to simulate both the field and the beam dynamics with the resulting varying beam loading. Other effects included in the simulation are Microphonics and Lorentz force. The code can simulate both single cavity and vector sum control.  
 
THPLT135 Experience with the 1.7 GHz Schottky Pick-ups in the Tevatron gun, proton, polarization, electron 2774
 
  • A. Jansson, P. Lebrun, R. Pasquinelli
    Fermilab, Batavia, Illinois
  During a 2003 shutdown, new high-frequency Schottky pick-ups were installed in the Tevatron. These devices operate at 1.7 GHz (harmonic ~36000 of the revolution frequency) and can in principle be used to measure tunes, chromaticities, momentum spread and transverse emittances of individual bunches. Only the transverse signal is used, as the longitudinal is dominated by coherent signal. The default mode of operation during a store is to sequentially acquire and analyze frequency data from different sets of bunches in the machine. This function is performed by an open access client written in Java/C++, running in the background. The resulting fit parameters are datalogged and can also be plotted in "real time" during the store. With an alternative setup, data from select bunches can be acquired continuously during the entire ramp (and squeeze), for analysis off-line. This paper describes the evolution, current status and performance of the acquisition and analysis software, and presents measurements with comparison to predictions and other measurement techniques. One example of such a measurement is the variation of beam-beam tune shift as a function of intensity and bunch position within a train.  
 
THPLT137 Commissioning of the Head-tail Monitoring Application for the Tevatron gun, proton, polarization, electron 2777
 
  • V.H. Ranjbar, V. Lebedev, E. Lorman, A. Xiao
    Fermilab, Batavia, Illinois
  A head-tail beam monitoring application has recently been developed for use in the Tevatron. With this application beam dynamics problems including head-tail instabilities can be monitored. In addition it can be use to perform chromaticity measurements using the head-tail technique developed at CERN. This application speeds up chromaticity measurements in the Tevatron especially during the acceleration ramp and low beta squeeze, which previously required three separate ramps using uncoalesced protons  
 
THPLT140 Commissioning of BL 7.2, the New Diagnostic Beamline at the ALS gun, proton, polarization, booster 2780
 
  • F. Sannibale, D. Baum, A. Biocca, N. Kelez, T. Nishimura, T. Scarvie, E. Williams
    LBNL, Berkeley, California
  • K. Holldack
    BESSY GmbH, Berlin
  BL 7.2 is a new beamline at the Advanced Light Source (ALS) dedicated to electron beam diagnostics. The system, which is basically a hard x-ray pinhole camera, was installed on the storage ring in August 2003 and the commissioning with the ALS electron beam followed immediately after. In this paper, the commissioning results are presented together with the description of the relevant measurements performed for the beamline characterization.  
 
THPLT141 Operational Experience Integrating Slow and Fast Orbit Feedbacks at the ALS gun, feedback, proton, polarization 2783
 
  • C. Steier, E.E. Domning, T. Scarvie, E. Williams
    LBNL, Berkeley, California
  A fast global orbit feedback system has been implemented at the ALS and is being used during user operation since this year. The system has two main purposes. The first is to meet the demands of some users for even improved (submicron) short term orbit stability. The second is to enable the use of more sophisticated insertion device compensation schemes (e.g. tune, beta-beating, coupling) for fast moving insertion devices like elliptically polarizing undulators, without deteriorating the orbit stability. The experience of routine user operation with the fast orbit feedback will be presented, as well as the overall feedback performance and how the integration issues with the already existing slow orbit feedback were solved.  
 
THPLT142 A Laser-Based Longitudinal Density Monitor for the Large Hadron Collider gun, feedback, proton, polarization 2786
 
  • S. De Santis, J.F. Beche, J.M. Byrd, P. Datte, M. Placidi, V. Riot, R.W. Schoenlein, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  We report on the development of an instrument for the measurement of the longitudinal beam profile in the Large Hadron Collider. The technique used, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store and display the required information. A 40 MHz laser, phase-locked to the ring radiofrequency system, with a 50 ps pulse length, would be suitable for measuring the dynamics of the core of each of the LHC 2808 bunches in a time span much shorter then the synchrotron period. The same instrument could also monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets ("ghost bunches") as required by the CERN specifications. We also specify the required characteristics of the diagnostic light port in the LHC where our instrument would be installed.

* Presently at Lawrence Livermore National Laboratory.

 
 
THPLT143 Development of an Abort Gap Monitor for the Large Hadron Collider gun, feedback, proton, polarization 2789
 
  • S. De Santis, J.F. Beche, J.M. Byrd, M. Placidi, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  The Large Hadron Collider, presently under construction at CERN, requires a monitor of the parasitic charge in the 3.3 ?s long gap in the machine fill structure, referred to as the abort gap, which corresponds to the raise time of the abort kickers. Any circulating particle present in the abort gap at the time of the kickers firing is lost inside the ring, rather than in the beam dump, and can potentially damage a number of the LHC components. CERN specifications indicate a linear density of 6x106 protons over a 100 ns interval as the maximum charge safely allowed in the abort gap at 7 TeV. We present a study of an abort gap monitor, based on a photomultiplier with a gated microchannel plate, which would allow for detecting such low charge densities by monitoring the synchrotron radiation emitted in the superconducting undulator dedicated to the measurement of the longitudinal beam properties. We show results of beam test experiments at the Advanced Light Source using an Hamamatsu 5916U MCP-PMT which indicate that such an instrument has the required sensitivity to meet LHC specifications.  
 
THPLT145 Automated High-power Conditioning of Medical Accelerators gun, feedback, proton, polarization 2792
 
  • S.M. Hanna, S. Storms
    Siemens Medical Solutions USA, Inc., Oncology Care Systems Group, Concord
  Medical accelerators require arc-free operation. Due to high-field emission, arcing and outgasing can occur in high-power accelerators. Therefore, the accelerator?s inner surfaces have to be conditioned before its use at high gradient levels in Radiation Therapy machine. At Siemens, we have developed a techniqu·101 to automatically condition an accelerator waveguide structure by continually inspecting the accelerator running conditions (arcing and vacuum) and stepping up the pulse repetition frequency (PRF) and RF power until reaching maximum power rating. The program implemented also reads, displays, and archives the data it collects along the full process of conditioning.  
 
THPLT146 Beam Diagnostics of the Small Isochronous Ring gun, feedback, proton, polarization 2795
 
  • J.A. Rodriguez, F. Marti
    NSCL, East Lansing, Michigan
  • E. Pozdeyev
    Jefferson Lab, Newport News, Virginia
  The purpose of this paper is to describe the beam diagnostic systems in the Small Isochronous Ring (SIR) developed and built at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). SIR is a small-scale experiment that simulates the dynamics of intense beams in large accelerators. A 20 to 30 keV hydrogen or deuterium ion bunch is injected in the ring, extracted after a variable number of turns and its longitudinal profile is studied. Some of the diagnostic tools available in SIR include an emittance measurement system in the injection line, scanning wires in different sections of the ring, phosphor screens at the injection and extraction points and a fast Faraday cup in the extraction line. The design of these systems and the kind of beam information they provide are discussed in detail.  
 
THPLT147 Beam Halo Monitoring on the CLIC Test Facility 3 gun, feedback, proton, polarization 2798
 
  • T. Lefevre
    NU, Evanston
  • H.-H. Braun, E. Bravin, R. Corsini, A.-L. Perrot, D. Schulte
    CERN, Geneva
  In high intensity accelerators, the knowledge of the beam halo distribution and its generation mechanisms are important issues. In order to study these phenomena, dedicated beam diagnostics must be foreseen. In circular machines, beam halo was monitored by using scrapers and beam loss detectors. In the framework of the CLIC project, beam halo monitoring is currently under development. The proposed device is based on an imaging system and a masking technique, which suppresses the core of the beam to allow direct observation of the beam halo. A first test was performed on the CLIC test facility 3 in 2003. We discuss the performances and the limitations of this technique pointing out our plans for future developments.  
 
THPLT148 Beam Loss Monitoring on the CLIC Test Facility 3 gun, feedback, proton, polarization 2801
 
  • T. Lefevre, M. Velasco, M. Wood
    NU, Evanston
  • H.-H. Braun, R. Corsini, M. Gasior
    CERN, Geneva
  The CLIC test facility 3 (CTF3) provides a 3.5A, 1.5s electron beam pulse of 150MeV at the end of the linac. The average beam power is 4 kW. Beam loss will be monitored all along the linac in order to keep the radiation level as low as possible. The heavy beam loading of the linac can lead to time transients of beam position and size along the pulse. To compensate these transients effectively a beam loss monitor (BLM) technology has to be chosen with a time response faster than a few nanoseconds. In this context, two different tests have been performed in 2003 on the already existing part of the CTF3 accelerator. Several detectors based on different technologies were first tested in parallel to determine which one was the most appropriate. A second test, in which the beam was intentionally lost in well defined conditions, was then made with the aim of comparing the measurements with simulation results. We present here the results of these tests and our conclusion for the new system to be developed.  
 
THPLT150 Results from Orbit and Optics Improvement by Evaluating the Nonlinear Beam Position Monitor Response in CESR gun, feedback, proton, polarization 2804
 
  • R.W. Helms, G. Hoffstaetter
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  In the Cornell Electron/positron Storage Ring (CESR), pretzel orbits with large horizontal oscillations are used to keep electron and positron beams out of collision except at the interaction point. Since a beam position monitor's (BPM's) response is only linear near the center of the beam pipe, the assumption of linearity does not allow for accurate orbit and phase measurements under colliding beam conditions. Using a numerical model of the BPMs' response to large offsets of the beam position, and an enhanced algorithm for real-time inversion of this nonlinear response function, we have extended our orbit and betatron phase measurements to beams with large pretzel amplitudes. Several measurements demonstrate the applicability, accuracy, and usefulness of this method.  
 
THPLT151 Evaluation of Beam Position Monitors in the Nonlinear Regime gun, feedback, proton, polarization 2807
 
  • R.W. Helms, G. Hoffstaetter
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Here we present a new algorithm for processing BPM signals and extracting orbit and phase data for very large beam excursion where the BPM response function changes nonlinearly with the beam position. Using two dimensional models of each BPM geometry, we calculate the button response using numerical solution of Laplace's equation and Green's reciprocity theorem. The difference between the calculated signals and the measured signals is minimized in real time to calculate the beam position and measurement errors. Using the derivatives of the response functions, we model the effect of beam shaking, and from it, calculate the betatron phase.  
 
THPLT152 Operation of the Position Measurements for the Isotope Production Facility gun, feedback, proton, polarization 2810
 
  • J.D. Gilpatrick, D.S. Barr, L.J. Bitteker, M.S. Gulley, D.M. Kerstiens, D. Martinez, J.F. O'Hara, C. Pillai, R.B. Shurter
    LANL/LANSCE, Los Alamos, New Mexico
  The Isotope Production Facility (IPF) will provide isotopes for medical purposes by using a 100-MeV H+-beam spur beam line from the Los Alamos Neutron Science Center (LANSCE) facility. Beam position measurements for IPF use a standard micro-stripline beam position monitor (BPM) with both an approximate 50-mm and 75-mm radius. The associated cable plant is unique in that it unambiguously provides a method of verifying the operation of the complete position measurement. The processing electronics module uses a log ratio technique with an error correcting software algorithm so that each the overall position measurement is periodically calibrated over a dynamic range of > 86 dB with errors less than 0.1 dB within this range. A National Instruments LabVIEW virtual instrument performs automatic periodic calibration and verification, and serves the data via the Experimental Physics and Industrial Control System (EPICS) channel access protocol. In order to report the data to the LANSCE facility operators and accelerator physicists, the served data are displayed and archived. This paper will describe the measurement system, commissioning and initial operating experiences.  
 
THPLT153 Commissioning and Initial Operation of the Isotope Production Facility at the Los Alamos Neutron Science Center gun, feedback, proton, polarization 2813
 
  • K.F. Johnson, H.W. Alvestad, W.C. Barkley, D.B. Barlow, D.S. Barr, G.A. Bennett, L.J. Bitteker, E. Bjorklund, W. Boedeker, M.J. Borden, R.A. Cardon, G. Carr, J.L. Casados, S. Cohen, J.F. Cordova, J.A. Faucett, M. Fresquez, F.R. Gallegos, J.D. Gilpatrick, F. Gonzales, F.W. Gorman, M.S. Gulley, M.J. Hall, D.J. Hayden, R.C. Heaton, D. Henderson, D.B. Ireland, G. Jacobson, G.D. Johns, D.M. Kerstiens, A.J. Maestas, A.R. Martinez, D. Martinez, G.C. Martinez, J. Martinez, M.P. Martinez, R. Merl, J.B. Merrill, J. Meyer, M.L. Milder, E.A. Morgan, F.M. Nortier, J.F. O'Hara, F.R. Olovas, M.A. Oothoudt, T.D. Pence, E.M. Perez, C. Pillai, F.P. Romero, C. Rose, L. Rybarcyk, G. Sanchez, J.B. Sandoval, S. Schaller, F.E. Shelley, R.B. Shurter, W. Sommer, M.W. Stettler, J.L. Stockton, J. Sturrock, T.L. Tomei, V.P. Vigil, P.L. Walstrom, P.M. Wanco, J. Wilmarth
    LANL/LANSCE, Los Alamos, New Mexico
  • R.E. Meyer, E.J. Peterson, F.O. Valdez
    LANL, Los Alamos, New Mexico
  The recently completed 100-MeV H+ Isotope Production Facility (IPF) at the Los Alamos Neutron Science Center (LANSCE) will provide radioisotopes for medical research and diagnosis, for basic research and for commercial applications. A change to the LANSCE accelerator facility allowed for the installation of the IPF. Three components make up the LANSCE accelerator: an injector that accelerates the H+ beam to 750-KeV, a drift-tube linac (DTL) that increases the beam energy to 100-MeV, and a side-coupled cavity linac (SCCL) that accelerates the beam to 800-MeV. The transition region, a space between the DTL and the SCCL, was modified to permit the insertion of a kicker magnet (23o kick angle) for the purpose of extracting a portion of the 100-MeV H+ beam. A new beam line was installed to transport the extracted H+ beam to the radioisotope production target chamber. This paper will describe the commissioning and initial operating experiences of IPF.  
 
THPLT154 Design of an X-ray Imaging System for the Low-Energy Ring of PEP-II gun, feedback, proton, polarization 2816
 
  • A.S. Fisher, D. Arnett, H. De Staebler, S. Debarger, R.K. Jobe, D. Kharakh, D.J. McCormick, M. Petree, M.C. Ross, J. Seeman, B. Smith
    SLAC, Menlo Park, California
  • J. Albert, D. Hitlin
    CALTECH, Pasadena, California
  • J. Button-Shafer, J.A. Kadyk
    LBNL, Berkeley, California
  An x-ray beam-size monitor for positrons in the low-energy ring (LER) of the PEP-II B Factory at SLAC is being designed to accommodate the present 2-A, 3.1-GeV beam and anticipated currents of up to 4.7 A. The final photon stop of an arc will be rebuilt to pass dipole radiation through cooled apertures to optics 17 m from the source. Zone-plate imaging there can achieve a resolution of 6 microns, compared to 35 for a pinhole camera. Two multilayer x-ray mirrors precede the zone plate, limiting the bandwidth to 1%, in order to avoid chromatic blurring and protect the zone plate. Despite the narrow bandwidth, the zone plate?s larger diameter compared to a pinhole camera allows for a comparable photon flux. We will image all 1700 LER bunches and also measure them individually, searching for variations along the train due to electron-cloud and beam-beam effects, using a scanning detector conceptually derived from a wire scanner. A mask with three narrow slots at different orientations will scan the image to obtain three projections. In one passage, signals from a fast scintillator and photomultiplier will be rapidly digitized and sorted to profile each bunch.  
 
THPLT155 Development and Testing of a Low Group-delay Woofer Channel for PEP-II gun, proton, polarization, booster 2819
 
  • J.D. Fox, L. Beckman, D. Teytelman, D. Van Winkle, A. Young
    SLAC, Menlo Park, California
  The PEP-II HER and LER require active longitudinal feedback to control coupled-bunch instabilities. The PEP-II RF systems use direct and comb loop feedback to reduce the cavity fundamental impedance, though the remaining low-mode impedance is providing the fastest growing unstable modes in both rings. Since commissioning the longitudinal feedback systems have used a dedicated "woofer" channel to apply the low-frequency correction kick via the RF system. The performance of this original controller is limited by the maximum gain that can be supported due to the processing delay (group delay), as well as the difficulty in configuring a common correction controller that acts via two correction paths. A dedicated low-mode signal processing system has been developed to allow higher damping rates. It is a digital processing channel, operating at a 10 MHz sampling rate, and implementing flexible 5 to 10 tap FIR control filters. The design of the channel and initial control filters is presented, as are initial machine experiments quantifying the damping and noise floor of this low group delay woofer system.  
 
THPLT156 Simulations of IP Feedback and Stabilization in the NLC gun, proton, polarization, booster 2822
 
  • L. Hendrickson, J.C. Frisch, T.M. Himel, T.O. Raubenheimer, A. Seryi, M. Woodley
    SLAC, Menlo Park, California
  • G.R. White
    Queen Mary University of London, London
  Keeping nanometer-sized beams in collision is an essential component in achieving design luminosity in a linear collider. The NLC stabilization strategy is conservative by including enough redundancy so that if some piece doesn't work to specification or the incoming beam motion is worse than expected, the beams will still be kept in collision. We show simulation results with both realistic and pessimistic assumptions about the response of the ground motion, inertial stabilization, interbunch and intertrain feedback systems. By providing backup systems, and by assuming that some systems may perform more poorly than expected, we can achieve a high level of confidence in our ability to successfully stabilize the beams.  
 
THPLT157 Beam-based Feedback for the NLC Linac gun, proton, polarization, booster 2825
 
  • L. Hendrickson, N. Phinney, A. Seryi, P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  The NLC linac train-by-train feedback system is designed to stabilize the beam trajectory, but is also a valuable element in the strategy for emittance preservation. New simulations employ improved strategies [*], allowing beam steering to be performed significantly less often than without the feedback system. Additional simulations indicate that the linac feedback can contribute towards successful operation at noisier sites.

* Beam-based Feedback Simulations for the NLC Linac, L. Hendrickson et al., LINAC, Monterey, California (2000)

 
 
THPLT159 Instability Thresholds and Generation of the Electron-cloud in the GLC/NLC and Tesla Damping Rings gun, proton, polarization, electron 2828
 
  • M.T.F. Pivi, T.O. Raubenheimer
    SLAC/NLC, Menlo Park, California
  In the beam pipe of the Damping Ring (DR) of a linear collider, an electron cloud may be produced by ionization of residual gas and secondary emission. This electron cloud can reach equilibrium after the passage of only a few bunches. We present recent computer simulation results for the main features of the electron cloud generation in the GLC/NLC main DR and for the TESLA DR. Single and multi-bunch instability thresholds are also calculated for the NLC main DR. The results are obtained by the computer simulation codes HEAD-TAIL and POSINST, which were developed to study the electron cloud effect in particle accelerators.  
 
THPLT160 Measurements of Transverse Coupled-bunch Instabilities in PEP-II gun, feedback, proton, polarization 2831
 
  • D. Teytelman, R. Akre, J.D. Fox, S.A. Heifets, A. Krasnykh, D. Van Winkle, U. Wienands
    SLAC, Menlo Park, California
  At the design currents the PEP-II High and Low Energy Rings operate above the coupled-bunch instability thresholds in horizontal and vertical planes. Both machines have used analog bunch-by-bunch feedback systems to stabilize the beams since commissioning. Here we present a measurement technique that uses the capabilities of the PEP-II programmable digital longitudinal feedback system to provide transient diagnostics in X or Y directions. This technique allows one to measure instability growth or damping rates as well as oscillation frequencies in both open-loop and closed-loop conditions. Based on these measurements the configuration of the relevant transverse feedback channel can be optimized. The technique will be illustrated with instability measurements and feedback optimization examples. Comparisons of the measured modal patterns and growth rates to the theoretical predictions will be presented.  
 
THPLT161 Compton X-ray Source feedback, proton, polarization, booster 2834
 
  • A.E. Vlieks, G. Caryotakis, D.W. Martin
    SLAC, Menlo Park, California
  • C.A. DeStefano, W.J. Frederick, J.P. Heritage, N.C. Luhmann Jr.
    UCD, Davis, California
  In an effort to develop a monochromatic, tunable source of X-rays in the 20-85 KeV energy range, a 5.5 cell X-band RF gun has been designed and tested. Together with a 1.05 m high gradient accelerating structure (an NLC Collider component), this system generates and accelerates a beam of electrons to energies greater than 60 MeV. Monochromatic X-rays are generated, via the Compton Effect, through a head-on collision of this beam with a multi-terawatt laser beam.We are currently measuring and analyzing the performance of the complete system, including the energy, monochromaticity and emittance of the electron beam, the laser system performance and the X-ray flux from the beam-laser interaction. A tunable, monochromatic X-ray source has important medical applications.We will report on the latest results as well as describe the experimental setup, components and diagnostics.  
 
THPLT162 Diagnosis of Coupling and Beta Function Errors in the PEP-II B-Factory feedback, proton, polarization, booster 2837
 
  • M.H. Donald, T.M. Himel, S. Zelazny
    SLAC, Menlo Park, California
  The SLAC Control program has an automatic phase measuring system whereby the beta functions of the two storage rings are measured. This facility has recently been extended to measure coupling between the horizontal and vertical motion and to fit the measured values to their modes of propagation. This facility aids the diagnosis and correction of coupling and focusing errors.  
 
THPLT163 High-temperature Kicker Electrodes for High-beam-current Operation of PEP-II proton, polarization, booster, laser 2840
 
  • U. Wienands, R. Akre, D.E. Anderson, S. Debarger, K. Fant, D. Kharakh, R.E. Kirby, A. Krasnykh, A. Kulikov, J. Langton
    SLAC, Menlo Park, California
  The strip line electrodes of the kickers used in the transverse bunch-by-bunch feedback systems see significant power deposition by beam and HOM-induced currents. This leads to elevated temperatures of the aluminum electrodes and will ultimately become a limit for the beam current in the Low Energy Ring. Heat is transported to the environment primarily by radiation from the blackened surface of the electrodes. In order to extend the beam-current range of these kickers, new electrodes have been fabricated from molybdenum which are able to run at significantly higher temperature, thus greatly increasing the efficiency of the radiative cooling of the electrodes. Blackening of the electrodes is achieved by oxidation in air at 1000°F using a recipe first applied in aviation research for supersonic aircraft. Emissivity was measured on coupons and a whole electrode to be about 0.6. In addition, the match at the terminations of the electrodes is improved following field calculations and measurements on a model of the kicker.  
 
THPLT165 Synchrotron Light Interferometry at JEFFERSON Lab proton, polarization, booster, laser 2843
 
  • A. Freyberger, P. Chevtsov, T. Day, R. Hicks
    Jefferson Lab, Newport News, Virginia
  • J-C. Denard
    SOLEIL, Gif-sur-Yvette
  The hyper-nuclear physics program at JLAB requires an upper limit on the RMS momentum spread of dp/p<3e-5. The momentum spread is determined by measuring the beam width at a dispersive location (D~4m) in the transport line to the experimental halls. Ignoring the epsilon-beta contribution to the intrinsic beam size, this momentum spread corresponds to an upper bound on the beam width of σ_beam<120um. Typical techniques to measure and monitor the beam size are either invasive or do not have the resolution to measure such small beam sizes. Using interferometry of the synchrotron light produced in the dispersive bend, the resolution of the optical system can be made very small. The non-invasive nature of this measurement allows continuous monitoring of the momentum spread. Two synchrotron light interferometers have been built and installed at JLAB, one each in the Hall-A and Hall-C transport lines. The devices operate over a beam current range from 1uA to 100uA and have a spatial resolution of 10um. The structure of the interferometers, the experience gained during its installation, beam measurements and momentum spread stability are presented. The dependence of the measured momentum spread on beam current will be presented.  
 
THPLT166 Development of Injection and Optics Control Applications for the SNS Accumulator Ring proton, polarization, booster, laser 2846
 
  • S.M. Cousineau, C. Chu, J. Galambos, S. Henderson, T. Pelaia, M. Plum
    ORNL/SNS, Oak Ridge, Tennessee
  • A.L. Leahman
    WSSU, Winston-Salem, North Carolina
  A large suite of physics software applications is being developed to facilitate beam measurement and control in the SNS accumulator ring. Two such applications are an injection control and measurement application, and a ring optics control application. The injection application will handle measurement and control of the linac beam position and angle at the stripper foil, and will be used to measure the twiss parameters of the linac beam at the foil. The optics control application will provide knobs for machine working point, chromaticity, arc phase advance, and harmonic correction. Both applications are written within the standard in-house XAL framework. Presented here are first versions of the applications, along with plans for future development and testing.  
 
THPLT167 SNS Laser Profile Monitor Progress proton, laser, polarization, booster 2849
 
  • W. Blokland, A.V. Aleksandrov, S. Assadi, C. Deibele, W. Grice, S. Henderson, T. Hunter, P. Ladd, G.R. Murdoch, J. Pogge, K. Potter, T.J. Shea, D. Stout
    ORNL/SNS, Oak Ridge, Tennessee
  • V. Alexandrov
    BINP SB RAS, Protvino, Moscow Region
  SNS will use a Nd:YAG laser to measure transverse profiles in the 186-1000 MeV super-conducting LINAC (SCL) and Ti:Sapphire modelock laser to measure longitudinal profiles in the 2.5 MeV Medium Energy Beam Transport (MEBT). The laser beam is scanned across the H- beam to photo-neutralize narrow slices. The liberated electrons are collected to provide a direct measurement of the transverse or longitudinal beam profile. We have successfully measured the transverse profile with a prototype system on the MEBT beam. The final SCL system uses an optical transport line that is installed alongside the 300 meter super-conducting LINAC to deliver laser light at 8 locations. Possible vibrations in the optical transport system can lead to inaccuracies in the profile measurement. We will use an active feedback system on a mirror to correct any vibration up to 2 KHz. In this paper we describe our vibration studies and vibration cancellation system as well as the progress in the design, installation and testing of various subsystems for both the transverse and the longitudinal profiles.  
 
THPLT168 XAL - The SNS Application Programming Infrastructure proton, laser, polarization, booster 2852
 
  • J. Galambos, C. Chu, S.M. Cousineau, T. Pelaia, A. Shishlo
    ORNL/SNS, Oak Ridge, Tennessee
  • C. Allen, C. McChesney
    LANL/LANSCE, Los Alamos, New Mexico
  • W.-D. Klotz
    ESRF, Grenoble
  • I. Kriznar, A. Zupanc
    Cosylab, Ljubljana
  A Java programming infrastructure for high level applications has been developed and is being used for the Spallation Neutron Source (SNS). The framework provides a hierarchal view of the accelerator and hides much of the underlying control system details. The hierarchy is database configured, facilitating sharing of applications across different beamlines, shielding the programmer from detailed knowledge of signal names, and allowing wholesale updating of applications. An important aspect of the framework is an online model, which can be run for design values, live machine values or user selected tuning values. Sample applications will be shown.  
 
THPLT170 Finding the Circular Magnet Aperture which Encloses an Arbitrary Number of Midplane-centered Beam Ellipses proton, laser, polarization, booster 2855
 
  • J.S. Berg
    BNL, Upton, Long Island, New York
  In specifying the magnets for an accelerator, one must be able to determine the aperture required by the beam. In some machines, in particular FFAGs, there is a significant variation in the closed orbit and beta functions over the energy range of the machine. In addition, the closed orbit and beta functions may vary with the longitudinal position in the magnet. It is necessary to determine a magnet aperture which encloses the beam ellipses at all energies and all positions in the magnet. This paper describes a method of determining the smallest circular aperture enclosing an arbitrary number of midplane-centered ellipses.  
 
THPLT171 Stochastic Cooling Studies in RHIC, II proton, laser, polarization, booster 2858
 
  • M. Blaskiewicz, J.M. Brennan, J. Wei
    BNL, Upton, Long Island, New York
  Intra-beam scattering is unavoidable for highly charged heavy ions and causes emittance growth during the store for collision physics. A longitudinal bunched beam stochastic cooling system will confine the bunch within the RF bucket increasing the useful luminosity. A single bunch, Palmer cooling system is under investigation. We present data and compare them with theory.  
 
THPLT172 Self-adaptive Feed Forward Scheme for the SNS Ring RF System proton, laser, polarization, booster 2861
 
  • M. Blaskiewicz, K. Smith
    BNL, Upton, Long Island, New York
  During one millisecond of injection stacking, the RF beam current varies from 0 to 50 Amperes. The control loops of the RF system are operative throughout this process. Acceptable setpoints will be found during commissioning, but as vacuum tubes age and beam currents increase these setpoints will become less optimal. A scheme by which the system can optimize itself is presented.  
 
THPLT173 RHIC BPM Performance: Comparison of Run 2003 and 2004 proton, laser, polarization, booster 2864
 
  • R. Calaga, R. Tomas
    BNL, Upton, Long Island, New York
  Identification of malfunctioning BPMs plays an important role in any orbit or turn-by-turn analysis. Singular value decomposition (SVD)and Fourier transform methods were recently employed to identify malfunctioning BPMs at RHIC. A detailed statistical comparison between the two methods for Run 2003 was in good agreement and proved to be a robust method to identify faulty BPMs. We evaluate detailed BPM performance for different versions of BPM low-level software in 2003 and 2004.  
 
THPLT177 Maps for Fast Electron Cloud Simulations at RHIC proton, laser, polarization, booster 2867
 
  • U. Iriso, S. Peggs
    BNL, Upton, Long Island, New York
  Luminosity in several colliders, including RHIC, is limited by the electron cloud effect. A careful re-distribution of the bunch pattern around the azimuth of a ring can decrease the average electron density for a fixed total bunch current, allowing the luminosity to be increased. In the search for a bunch pattern that maximizes the luminosity, a fast computer simulation is a key requirement. We discuss the use of fast polynomial maps to simulate the bunch to bunch evolution of the electron density at RHIC. Such maps are empirically derived from existing conventional slow simulation codes.  
 
THPLT179 MADX-UAL Suite for Off-line Accelerator Design and Simulation proton, laser, polarization, booster 2870
 
  • N. Malitsky, R.P. Fliller III, F.C. Pilat, V. Ptitsyn, S. Tepikian, J. Wei
    BNL, Upton, Long Island, New York
  • F. Schmidt
    CERN, Geneva
  • R.M. Talman
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  We present here an accelerator modeling suite that integrates the capability of MADX and UAL packages, based on the Standard eXchange Format (SXF) interface. The resulting environment introduces a one-stop collection of accelerator applications ranging from the lattice design to complex beam dynamics studies. The extended capabilities of the MADX-UAL integrated approach have been tested and effectively used in two accelerator projects: RHIC, where direct comparison of operational and simulated data is possible, and the SNS Accumulator Ring, still in its design phase.  
 
THPLT181 A Tomographic Technique for Magnetized Beam Matching proton, laser, polarization, booster 2873
 
  • C. Montag, I. Ben-Zvi, J. Kewisch
    BNL, Upton, Long Island, New York
  To maintain low electron beam temperatures in the proposed RHIC electron cooler, careful matching of the magnetized beam from the source to the cooler solenoid is mandatory. We propose a tomographic technique to diagnose matching conditions. First simulation results will be presented.  
 
THPLT183 Results from the Commissioning of the NSRL Beam Transfer Line at BNL laser, polarization, booster, luminosity 2876
 
  • N. Tsoupas, S. Bellavia, R. Bonati, K.A. Brown, I.-H. Chiang, C. Gardner, D. Gassner, S. Jao, I. Marneris, A. McNerney, D. Phillips, P. Pile, R. Prigl, A. Rusek, L. Snydstrup
    BNL, Upton, Long Island, New York
  The NASA SPACE RADIATION LABORATORY (NSRL) has started operations at the Brookhaven National Laboratory in 2003. The NSRL facility will be used by NASA to study radiation effects. The NSRL facility utilizes proton and heavy-ion beams of energies from 50 to 3000 MeV/n which are accelerated by the AGS_Booster synchrotron accelerator. The beams were extracted[1] ,and transported to a sample which is located 100 m downstream. To date, protons, 12C, 56Fe, 48Ti ion beams of various magnetic rigidities have been transported to the sample location. The NSRL beam transport line has been designed to employ octupole magnetic elements[2] which transform the normal (Gaussian) beam distribution on the sample into a beam with rectangular cross section, and uniformly distributed over the sample. No beam-collimation is applied along any point of the NSRL beam transport line and the beam focusing on the sample is purely magnetic. The experimental and theoretical horizontal and vertical beam envelopes of the first order optics will be presented. The theoretical beam profiles and uniformities at the location of the sample, when the magnetic octupoles are excited (third order optics), will be compared with the experimentally measured ones.  
 
THPLT184 An Online Longitudinal Vertex and Bunch Spectrum Monitor for RHIC laser, polarization, booster, luminosity 2879
 
  • J. Van Zeijts, R. Lee
    BNL, Upton, Long Island, New York
  The longitudinal bunch profile acquisition system at RHIC was recently upgraded to allow online measurements of the bunch spectrum, and collision vertex location and shape. The system allows monitoring the evolution of these properties along the ramp, at transition and rebucketing, and at store conditions. We describe some of the hardware and software changes, and show an application of the system in optimizing the cogging of the colliding beams.  
 
THPLT186 Bunch Pattern Control in Top-up Mode at the SLS laser, polarization, booster, luminosity 2882
 
  • B. Kalantari, T. Korhonen, V. Schlott
    PSI, Villigen
  One of the crucial issues in the advanced third generation light sources is the bunch pattern control in the storage ring, where various filling patterns are of interests for different experiments. The most important step is to keep a uniform charge distribution over all (electron) bunches during the top-up operation. Such a bunch pattern control has been implemented at the Swiss Light Source (SLS). It provides a filling pattern with bunch-to-bunch fluctuation of a few percent. Since a dependency of the medium term orbit stability on the actual filling pattern was observed in the past, the stability could significantly be improved. Three major ingredients have made the implementation possible: precise timing system, flexible control system and sophisticated diagnostics. The method is being used in the user operation recently and proved to be reliable. This paper describes the hardware and software involved in the mentioned technique.  
 
FRXCH01 Development of High Power Targets laser, polarization, booster, target 276
 
  • G.S. Bauer
    FZJ/ESS, Jülich
  High power targets are at the very heart of most applications of accelerators to science and technology. With many projects aiming to utilize beams in the multi-megawatt power range, solid targets, in particular stationary ones, become increasingly difficult. Liquid metal targets have become the concept of choice. Designs cover a variety of concepts ranging from free jets to allow extraction of low energy ? highly ionizing radiation (pions and muons) to fully enclosed systems if neutron generation is the main goal. Mercury is often the preferred target material due to its liquid state at room temperature and other favourable properties. Designs aiming at high temperature operation depending on small neutron absorption rely on PbBi as target material. Liquid lithium is proposed for a deuteron stripping target for the IFMIF project. Questions that need to be solved include solid-liquid metal reactions, radiation effects, general liquid metal technology, handling of spallation products as well as design of components and subsystems. In addition, short pulse operation leads to the generation of pressure waves inside the targets and the need to control their consequences.  
Video of talk
Transparencies
 
FRXBCH01 Novel Ideas and R&D for High Intensity Neutrino Beams laser, polarization, booster, target 281
 
  • K.J. Peach
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  Recent developments in neutrino physics, primarily the conclusive demonstration of neutrino oscillations in both atmospheric neutrinos and solar neutrinos, provide the first conclusive evidence for physics beyond the Standard Model of particle physics. The phenomenology of neutrino oscillations, for three generations of neutrino, requires six parameters - two squared mass differences, 3 mixing angles and a complex phase that could, if not 0 or pi, contribute to the otherwise unexplained baryon asymmetry observed in the Universe. Exploring the neutrino sector will requires very intense beams of neutrinos, and needs novel solutions.  
Video of talk
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FRXBCH02 Towards Higher Luminosities in B and Phi Factories laser, polarization, booster, target 286
 
  • P. Raimondi
    INFN/LNF, Frascati (Roma)
  A brief review of the performances of the existing Factories will be presented. Such machines have been proved extremely successful, for both particle and accelerator physics. To further extend their physics reach, several plans are under way to upgrade the existing colliders, in order to increase their luminosity up to an order of magnitude. Will also be described several new schemes and ideas to realize full ?Second Generation Factories? aimed at luminosities two order of magnitude higher then what achieved so far.  
Video of talk
Transparencies
 
FRYACH01 HICAT - The German Hospital-Based Light Ion Cancer Therapy Project laser, polarization, booster, target 290
 
  • H. Eickhoff, T. Haberer, B. Schlitt, U. Weinrich
    GSI, Darmstadt
  At the University Clinics at Heidelberg /Germany the realization of a cancer Therapy facility using light and medium ions (from protons up to oxygen) has started. This facility will be capable to treat about 1000 patients per year by means of the 'intensity controlled rasterscan technique', that has been already successfully applied to about 200 patients since 1998 at the GSI therapy pilot project. The presentation will give an overview of the facility layout and especially the accelerator- and beam transport systems, capable to provide 3 treatment places with light ions between 50 and 430 MeV/u. Two treatment places are located after horizontal beam lines and one after an isocentric gantry. A further horizontal beam line for research and development activities is foreseen. Besides the technical description and the status and schedule for the project realization organizational aspects of this project will be discussed with the project leadership at the University Clinics, the strong technical assistance of GSI and the role of industrial partners.  
Video of talk
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FRYBCH01 Clean Energy and the Fast Track to Fusion Power laser, polarization, booster, target 295
 
  • C. Llewellyn Smith
    UKAEA Culham, Culham, Abingdon, Oxon
  The theoretical attractions of fusion are clear: used as fuel in a fusion power plant, the lithium in one laptop battery together with 40 litres of water would produce 200,000 kW hours of electricity in an environmentally benign manner. The Joint European Torus (JET), which has produced 16MW, has shown that fusion can work in practice. ITER (the International Tokamak Experimental Reactor) is now essential to test integration of the components at the heart of a fusion reactor, and confirm that a burning plasma, in a fusion device scaled up in all dimensions by a factor of two from JET, to power plant size, has the expected behaviour. ITER should confirm that a fusion power plant can be built. The challenge will then be to build a power plant that would be sufficiently reliable and robust to be economically viable. This will require intensive research and development on the materials needed to construct the plasma vessel and surrounding blanket. These materials will have to be tested under reactor conditions at a dedicated facility called IFMIF (International Fusion Materials Facility). Construction of IFMIF in parallel with ITER would put fusion firmly on the 'fast track' (strongly advocated by the British Government) to the construction of a commercial fusion power plant, which could in principle be in operation within 30 years. I shall describe how a fusion power plant would work, the advantages and disadvantages of fusion, and the challenges that lie ahead.  
Video of talk
Transparencies