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Paper Title Other Keywords Page
MOPA008 On the Feasibility of a Tripler Upgrade for LHC dipole, photon, injection, multipole 634
  • P.M. McIntyre, A. Sattarov
    Texas A&M University, College Station, Texas
  Funding: This work is supported by the U.S. Dept. of Energy, grant #DE-FG03-95ER40924.

Recent developments in the performance of superconductors and the design of high-field superconducting dipoles have opened the possibility to extend dipole field strength to ~25 Tesla in the arc dipoles of a future hadron collider. Design issues are presented for a concept of a Tripler upgrade of LHC, in which a second dual ring would be installed over the LHC ring in the same tunnel. Proton beams from LHC would be transferred to the Tripler midway through the LHC cycle and accelerated to ~20 TeV/beam for collisions. A number of obvious issues are explored. Synchrotron radiation power would be 80 times greater, but the critical energy would come as soft X-rays rather than hard UV, and so could be absorbed locally on ~150 K photon stops following each dipole so that total refrigeration power could perhaps be no more than that for LHC. Synchrotron damping would be dramatically enhanced in the Tripler compared to LHC, with damping times of ~one hour. Alternatives for beam transfer and low-beta insertions will be discussed. Like LHC, the Tripler would access new mass scales primarily through gluon fusion. The Tripler should reach about twice the mass scale attainable with LHC.

MOPC005 Chromaticity and Impedance Effect on the Transverse Motion of Longitudinal Bunch Slices in the Tevatron simulation, impedance, damping, beam-losses 455
  • V.H. Ranjbar
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the U.S. Department of Energy.

The Transverse turn-by-turn evolution of a bunch slice are examined considering chromatic and impedence effects. A quasi-analytical approximation is developed using perturbative expansion of Hills equation with a wake field. This approximation is compared to turn-by-turn measurements taken in the Tevatron and from this linear and second order chomaticity, and Impedence are calculated as well as beam stability thresholds.

MPPE012 MAD-X PTC Integration lattice, optics, radiation, synchrotron-radiation 1272
  • F. Schmidt
    CERN, Geneva
  MAD-X is CERN's successor for MAD8, a program for accelerator design with a long history. MAD-X is a modular, better maintainable re-write of MAD8 with data structures written in C. Early on in the design of MAD-X we relied on the fact that older or doubtful modules could be replaced by new modules using the PTC code by E. Forest. Both codes remain independent entities but are linked via a converter to the MAD-X data structures. PTC is used for symplectic tracking of smaller machines and transfer line using better defined physical models of the elements and taking into account of how the elements are placed in the tunnel. The matching of the LHC will profit form the fact that the high order nonlinear parameters are provided by a PTC Normal Form analysis.  
MPPE038 Synchrotron Sidebands of a Linear Differential Coupling Resonance resonance, coupling, betatron, storage-ring 2538
  • M. Takao, M. Masaki, J. Schimizu, K. Soutome, S. Takano, H. Tanaka
    JASRI/SPring-8, Hyogo
  Sidebands of a linear differential coupling resonance are observed in the tune survey of the SPring-8 storage ring. The vertical beam size and the Touschek beam lifetime blow up at a distance by synchrotron tune from the linear differential resonance. The synchrotron sidebands of a linear betatron coupling resonance are excited by the vertical dispersion at sextupole magnets. Although the vertical dispersion of the SPring-8 storage ring is well reduced to be small, order of 1 mm, the linear betatron coupling resonance is further suppressed. In addition, the sextupole magnets are relatively strong as well as other third generation light source facilities. Hence at the SPring-8 storage ring we can observe the synchrotron sidebands of the coupling resonance. By means of the tracking simulation based on the ring model obtained by the response matrix measurement we confirm the existence of the synchrotron sidebands of a linear differential coupling resonance. In order to incorporate synchrotron motion in the simulation, the 6-dimensional tracking code developed at SPring-8 is used.  
MPPE041 Orbit Stability at the Brazilian Synchrotron Light Source shielding, dipole, vacuum, quadrupole 2687
  • L. Liu, P.F. Tavares
    LNLS, Campinas
  A task force has been implemented at the Brazilian Synchrotron Light Laboratory to improve the beam orbit stability in the 1.37 GeV electron storage ring. The main problems faced during this year (2004) were due to the installation of a second RF cavity in the machine. We describe the main problems and the solutions that were implemented.  
MPPE049 Sensitivity Study for Evaluating the Extracted Beam Parameters of the LLUMC Proton Therapy Synchrotron optics, emittance, proton, target 3046
  • G.H. Gillespie, W. Hill
    G.H. Gillespie Associates, Inc., Del Mar, California
  • G. Coutrakon, J. Hubbard, E. Sanders
    LLU/MC, Loma Linda, California
  The MINOS nonlinear constrained optimization program, working in concert with the beam optics code TRANSPORT, has been shown in recent work to provide a fast, efficient and reliable procedure for determining the parameters of the beam extracted from the LLUMC proton therapy synchrotron. MINOS and TRANSPORT work together as Modules of the Particle Beam Optics Laboratory (PBO Lab) software. The software was used to determine the parameters of the beam extracted from the synchrotron accelerator that best fit the extensive wire scanner profile data used to monitor the LLUMC proton therapy beamlines. In this paper additional constraints and optimizer variables are utilized with the procedure, in order to evaluate the sensitivity of the best fit extracted beam parameters to various assumptions. The methods used will be described and selected results from the study presented.  
MPPE066 Streak Camera Studies of Vertical Synchro-Betatron-Coupled Electron Beam Motion in the APS Storage Ring electron, betatron, storage-ring, kicker 3694
  • B.X. Yang, M. Borland, W. Guo, K.C. Harkay, V. Sajaev
    ANL, Argonne, Illinois
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.

We present experimental studies of synchro-betatron-coupled electron beam motion in the Advanced Photon Source storage ring. We used a vertical kicker to start the beam motion. When the vertical chromaticity is nonzero, electrons with different initial synchrotron phases have slightly different betatron frequencies from the synchronous particle, resulting in a dramatic progression of bunch-shape distortion. Depending on the chromaticity and the time following the kick, images ranging from a simple vertical tilt in the bunch to more complicated twists and bends are seen with a visible light streak camera. Turn-by-turn beam position monitor data were taken as well. We found that the experimental observations are well described by the synchro-betatron-coupled equations of motion. We are investigating the potential of using the tilted bunch to generate picosecond x-ray pulses. Also note that the fast increase in vertical beam size after the kick is dominated by the internal synchro-betatron-coupled motion of the electron bunch. Experimentally this increase could be easily confused with decoherence of vertical motion if the bunch is only imaged head-on.

MPPE069 Optics for the ALBA Lattice lattice, insertion, insertion-device, vacuum 3777
  • M. Muñoz, D. Einfeld
    CELLS, Bellaterra (Cerdanyola del Vallès)
  ALBA will be a third generation synchrotron light source built in Spain near Barcelona. The lattice chosen for ALBA consists in an extended DBA-like structure with finite dispersion in the straight sections, providing low emittance (under 5nmrad), small beam cross sections at the source points (σ x ~ 150 micrometers and σ y ~ 10micrometers), and a large number of straight sections (4 times 8m, 12 times 4.2m and 8 times 2.6m). The small circumference (268 meters) and medium energy (3GeV) makes it challenging to provide the desired emittance while preserving a large enough dynamic aperture and energy acceptance. This paper reviews the main beam dynamics issues (dynamic aperture, energy acceptance, closed correction, lifetime, influence of insertion devices, and higher multipoles of magnets) and the solutions adopted.  
MPPE073 Effects of the Passive Harmonic Cavity on the Beam Bunch radiation, beam-loading, impedance, electron 3904
  • L.-H. Chang, M.-C. Lin, C. Wang, M.-S. Yeh
    NSRRC, Hsinchu
  In this paper, we present a computer tracking code, which can investigate the bunch length, energy spread and the critical current of Robinson instability under the influence of the passive harmonic cavity. The effects of the radiation damping, quantum excitation and the beam loading of the harmonic cavity are included in the computation. The calculated result shows that the beam has a constant energy spread and blows up as the beam current increases from below to over the threshold current of the Robinson instability. It also indicates that the shunt impedance of the harmonic cavity is critical for whether the harmonic cavity can reach the designed goal, a stable and lengthening beam at the design beam current.  
MPPP001 A Vertical Multi-Bunch Feedback System for ANKA feedback, kicker, storage-ring, injection 761
  • P. Wesolowski, I. Birkel, E. Huttel, A.-S. Müller, M. Pont, F. Pérez
    FZK, Karlsruhe
  ANKA is a synchrotron light source with a top energy of 2.5 GeV. The maximum electron current at ANKA is presently limited by multi-bunch instabilities to 200 mA. In order to overcome this barrier a transverse analog multi-bunch feedback system is presently being commissioned. A BPM is used for beam detection. The vertical position signal passes a notch filter, is amplified, and subsequently fed to a vertical beam kicker. The present paper shows the layout of ANKA feedback system and discusses the first results of its operation.  
MPPP003 FALSE BPM READINGS AFFECTING ORBIT FEEDBACK feedback, vacuum, insertion, insertion-device 847
  • H.-S. Kang, J. Choi, M.-H. Chun, K.M. Ha, J.Y. Huang, Y.-C. Kim, E.-H. Lee, T.-Y. Lee, W.W. Lee, J.-H. Suh
    PAL, Pohang, Kyungbuk
  Funding: Ministry of Science and Technology, Korea.

A slow global orbit feedback (SOFB) is routinely operating in the usual user service operation at PLS. The orbit feedback uses 22 correctors in each plane which have 20-bit capability for the vertical plane and 16-bit capability for the horizontal plane, and the feedback speed is 4 seconds. The orbit stability in RMS was maintained below 1 mm in both planes for one hour and 3 mm for a 12-hour operation. The BPM chamber movement due to the change of synchrotron radiation heat load mainly limits the SOFB performance. The intensity dependence of BPM electronics is well compensated by a look-up table of BPM.

MPPP010 Feedback to Suppress Phase Noise at Aladdin feedback, dipole, simulation, damping 1180
  • R.A. Bosch, K. Jacobs, K. J. Kleman
    UW-Madison/SRC, Madison, Wisconsin
  The performance of the Aladdin infrared beamline is adversely affected by a Robinson mode in which all bunches move in unison with a frequency of 3 kHz. To decrease these oscillations, feedback has been installed in the radiofrequency system to damp longitudinal motion of the bunch centroids. Simulations indicate that at frequencies around 3 kHz, the phase noise generated by Robinson modes may be reduced 20 dB by feedback with a damping time of 0.3 ms. This agrees with the measured performance of feedback circuitry. Since the feedback greatly improves operation of the infrared beamline, it is now incorporated into the standard operation of Aladdin.  
MPPP020 RF Phase Modulation at the LNLS Electron Storage Ring simulation, single-bunch, resonance, beam-loading 1686
  • N.P. Abreu, N.P. Abreu
    UNICAMP, Campinas, São Paulo
  • R.H.A. Farias, P.F. Tavares
    LNLS, Campinas
  Funding: FAPESP

In the Brazilian Electron Storage Ring, we observed that modulating the phase of accelerating fields at twice the synchrotron frequency suppressed remarkably well a longitudinal coupled-bunch mode of the beam driven by one of the RF cavities. We present results of a set of systematic measurements, in single and multi-bunch mode, aimed at characterizing the effects of the modulation on the beam. We also compare those experiments with the results of tracking simulations.

MPPP022 The Impedance of Selected Components of the Synchrotron Light Source Petra III impedance, vacuum, dipole, insertion 1751
  • R. Wanzenberg, K. Balewski
    DESY, Hamburg
  At DESY it is planned to convert the PETRA ring into a synchrotron radiation facility, called PETRA III, in 2007. Since the impedance of the machine determines its performance with respect to coupled and single bunch instabilities it is important to know the wakefields and higher order modes (HOMs) of the different components of the vacuum system. Numerical calculations of wakefields and HOMs are presented for several components of PETRA III, including the rf-cavities, shielded bellows and tapered vacuum chamber transitions. The impedance of these components is presented in terms of the loss and kick parameters.  
MPPP027 Suppression of the Longitudinal Coupled-Bunch Instabilities by the RF Phase Modulation in the Pohang Light Source simulation, higher-order-mode, storage-ring, damping 1970
  • I. Hwang, M. Yoon
    POSTECH, Pohang, Kyungbuk
  • Y.J. Han, E.-S. Kim, J.S. Yang
    PAL, Pohang, Kyungbuk
  In the 2.5 GeV Pohang Light Source, we have investigated the suppression of the longitudinal coupled instabilities (CBI) caused by higher order modes (HOMs) of RF cavities. At higher beam current than 170 mA the 758 MHz or 1300 MHz HOMs occurred and the beam could be unstable. The longitudinal CBI could be suppressed by modulating the phase of an RF accelerating voltage at a frequency of 2 times the synchrotron oscillation frequency and by adjusting the water temperatures of the RF cavities. The longitudinal beam oscillations measured by streak camera in synchro-scan mode were shown. The experiment results were compared with the macro particle tracking simulation.  
MPPP028 The Code MBIM1 for the Calculation of the Multibunch Beams Coherent Oscillations Stability (in Approach of Short Bunches) multipole, electron, storage-ring, positron 2009
  • N. Mityanina
    BINP SB RAS, Novosibirsk
  The code MBIM1 for the calculation of the coherent oscillations stability for multibunch beams in storage rings is presented. The multibunch beams with arbitrary charges of bunches are considered, including counterrotating bunches (in approach of short bunches in comparison with minimal wavelength of considered environment RF spectrum), with the account of beams coupling with the environment (i.e. RF cavities or/and smooth vacuum chamber with walls of finite conductivity). The code uses the approach of small shifts of coherent frequencies, when different multipole types of synchrotron oscillations can be treated as independent from each other.  
MPPP029 The Code MBIM2 for the Calculation of the Arbitrary Multibunch Beams Longitudinal Coherent Oscillations Stability (in the Case of Long Bunches) multipole, damping, impedance, single-bunch 2110
  • N. Mityanina
    BINP SB RAS, Novosibirsk
  The presented code is an advanced version of the code MBIM1 also presented at this conference and dealing with short bunches. The code MBIM2 analyses the stability of longitudinal coherent motion for arbitrary multibunch beams in storage rings without limitations on the bunch length or RF cavities wavelength, which is especially important for higher types of multipole synchrotron oscillations. The code implies also the possibility to consider coupling between different types of multipole synchrotron oscillations and Landau damping. In considered approach, the problem reduces to the eigenvalue problem for the linear algebraic equation system. The order of this system is equal to the number of bunches times number of multipole types times approximation order wich appears to be small (a few units) in most cases.  
MPPP030 Analytic Evaluation of the Series over Azimuthal Harmonics at the Analysis of the Stability of Bunched Beams Coherent Oscillations impedance, multipole, coupling, RF-structure 2149
  • N. Mityanina
    BINP SB RAS, Novosibirsk
  At the analysis of the stability of coherent motion of multibunch beams including counterrotating beams) one should deal with expressions analogous to the effective impedance - the serieses over harmonics of revolution frequency of the RF structure impedance at the side frequencies to these harmonics, with certain factors depending on the harmonic number, such as the bunch line density spectrum, the phase factor and the factor describing the order of multipole synchrotron oscillations. In this paper, we present the method for analytic summation of these serieses for resonant impedance, which seems not to be made before in the common case including all mentioned factors. Comparison of obtained expressions with formulae used in previous papers shows the limits of validity of simpler approaches. The obtained expressions are used in the computer codes MBIM1 and MBIM2 presented at this conference, which calculate coherent oscillations stability for arbitrary multibunch beams.  
MPPP033 Beam Transfer Functions and Beam Stabilisation in a Double RF System damping, injection, beam-loading, space-charge 2300
  • E.N. Shaposhnikova, T. Bohl, T.P.R. Linnecar
    CERN, Geneva
  The high intensity proton beam for LHC accelerated in the CERN SPS is stabilised against coupled-bunch instabilities by a 4th harmonic RF system in bunch-shortening mode. Bunch-lengthening mode, which could also be useful to reduce peak line density and alleviate problems from e-cloud and kicker heating does not give desirable results for beam stability. In this paper an analysis of the limitations of these two different modes of operation is presented together with measurements of the Beam Transfer Function for the double RF system. As predicted by theory, for sufficiently long bunches with the same noise excitation, the measured amplitude of the beam response in bunch-lengthening mode is an order of magnitude higher than that for bunch-shortening mode or for a single RF system.  
MPPP035 Investigation of APS PAR Vertical Beam Instability ion, injection, linac, electron 2393
  • C. Yao, Y.-C. Chae, N. Sereno, B.X. Yang
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

The Advanced Photon Source (APS) particle accumulator ring (PAR) is a 325-MeV storage ring that collects and compresses linac pulse trains into a single bunch for booster injection. A vertical beam instability has been observed when only a single linac bunch is injected and the total beam charge is from 0.15 to 0.7 nC. The instability starts about 80 ms after the injection, lasts about 160 ms, and is highly reproducible. We performed spectral measurement and time-resolved imaging with both a gated-intensified camera and a streak camera in order to characterize this instability. Initial analysis of the data indicates that the instability is due to ion trapping. A stable lattice was established as result of the investigation. This report summarizes the experimental results and gives some preliminary analysis.

MPPP038 Harmonic Cavity Performance for NSLS-II undulator, damping, emittance, brightness 2544
  • A. Blednykh, S. Krinsky, B. Podobedov, J. Rose, N.A. Towne, J.-M. Wang
    BNL, Upton, Long Island, New York
  NSLS-II is a 3 GeV ultra-high brightness storage ring that is planned to succeed the present NSLS rings at Brookhaven. Ultra-low emittance bunch combined with a short bunch length results in the Touschek lifetime of only a few hours, which strongly advocates including harmonic RF in the baseline design of NSLS-II. This paper describes the required harmonic RF parameters, trade-offs between the possible choices and the expected system performance, including the implications on lifetime and instabilities.  
MPPP041 Transverse Instability of a Rectangular Bunch impedance, space-charge, emittance, damping 2657
  • V. Balbekov
    Fermilab, Batavia, Illinois
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-76CH03000.

Some results of theoretical investigations of transverse dipole instability of a rectangular bunch are reported in this paper. Such a form is characteristic of the bunch in a rectangular potential wall which is created by a barrier-shaped acceleration field. Similar regime is a major one for accumulating and cooling of antiproton beams in the Fermilab Recycler Ring. In this case, the known theory of transverse instability of a bunched beam is inapplicable directly both because of "unusual" form of phase trajectories and strong dependence of synchrotron frequency on energy. A series of equations, adequately describing the instability is derived in the paper. Exact analytical solution is obtained for space charge dominated impedance, and some approximate methods are proposed for arbitrary impedance. The theory is applied to the Fermilab Recycler Ring including a numerical simulation.

MPPT020 Magnetic Field Measurement on a Refined Kicker kicker, injection, radiation, storage-ring 1682
  • T.-C. Fan, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  To prepare for the operation of top-up mode and increase the efficiency of injection at storage ring, National Synchrotron Radiation Research Center (NSRRC) has upgraded the kicker magnets and power supply. We have built up a new magnetic field measurement system to test the kicker. This system, including a search coil and a coil loop, can map the field and take the first integral of field automatically. We also simulate the trajectory of electron beam by pulsed wire method of field measurement. We analyze the performance of the kicker system in this paper.  
MPPT032 Construction and Performance of Superconducting Magnets for Synchrotron Radiation electron, wiggler, radiation, multipole 2218
  • C.-S. Hwang, C.-H. Chang, C.-K. Chang, H.-P. Chang, C.-T. Chen, H.-H. Chen, J. Chen, J.-R. Chen, Y.-C. Chien, T.-C. Fan, G.-Y. Hsiung, K.-T. Hsu, S-N. Hsu, M.-H. Huang, C.-C. Kuo, F.-Y. Lin
    NSRRC, Hsinchu
  Two superconducting magnets, one wavelength shifter (SWLS) with a field of 5 T and one wiggler (SW6) with a field of 3.2 T, were constructed and routinely operated at NSRRC for generating synchrotron x-rays. In addition, three multipole wigglers (IASW) with fields of 3.1 T will be constructed and installed each in the three achromatic short straight sections. A warm beam duct of 20 mm inner gap and a 1.5 W GM type cryo-cooler were chosen for the SWLS to achieve cryogen-free operation. For the SW6, a cold beam duct of 11 mm inner gap was kept at 100 K temperature and no trim coil compensation is necessary for its operation. Meanwhile, no beam loss was observed when the SW6 was quenched. A cryogenic plant with cooling power of 450 W was constructed to supply the liquid helium for the four superconducting wigglers. The design concept, magnetic field quality, the commissioning results, and the operation performance of these magnets will be presented.  
MPPT075 Analysis and Design of Backing Beam for Multipole Wiggler (MPW14) at PLS multipole, wiggler, synchrotron-radiation, radiation 3940
  • H.-G. Lee, C.W. Chung, H.S. Han, Y.G. Jung, D.E. Kim, W.W. Lee, K.-H. Park, H.S. Suh
    PAL, Pohang, Kyungbuk
  Pohang Accelerator Laboratory (PAL) had developed and installed a Multipole Wiggler (MPW14) to utilize high energy synchrotron radiation at Pohang Light Source (PLS). The MPW14 is a hybrid type device with period of 14 cm, minimum gap of 14 mm, maximum flux density of 2.02 Tesla and total magnetic structure length of 2056 mm. The support locations and structure of an insertion device are optimized to achieve a minimum deflection due to the magnetic loads. A Finite Element Analysis (FEA) is performed to find out the amount of maximum deflection and optimal support positions on the backing beam, the support and drive structures of the MPW14 under expected magnetic load of 14 tons. To reduce the deflection effect further, two springs are designed and installed to compensate the gap dependent magnetic loads. The optimized deflection is estimated to be about 20.6 ? while the deflection before optimization is 238 ?.  
MPPT083 Radiation Damage to Advanced Photon Source Undulators radiation, undulator, electron, vacuum 4126
  • S. Sasaki, C. Doose, E.R. Moog, M. Petra, I. Vasserman
    ANL, Argonne, Illinois
  • N.V. Mokhov
    Fermilab, Batavia, Illinois
  Funding: Supported by the U.S. DOE Office of Science under Contract No. W-31-109-ENG-38.

Radiation-induced magnetic field strength losses are seen in undulator permanent magnets in the two sectors with small-aperture (5 mm) vacuum chambers. Initially, simple retuning of the affected undulators could restore them to full operation. As the damage has accumulated, however, it has become necessary to disassemble the magnetic arrays and either replace magnet blocks or remagnetize and reinstall magnet blocks. Some of the damaged magnet blocks have been studied, and the demagnetization was found to be confined to a limited volume at the surface close to the electron beam. Models for the magnetic damage were calculated using RADIA* and were adjusted to reproduce the measurements. Results suggest that a small volume at the surface has acquired a weak magnetization in the opposite direction. Small magnet samples provided by NEOMAX and Shin-Etsu are being placed in the storage ring tunnel for irradiation exposure testing. Simulations of the radiation environment at the undulators have been performed.

*O. Chubar, P. Elleaume, J. Chavanne, J. Synchrotron Radiat. 5, 481 (1998).

MPPT090 Design, Construction and Field Characterization of a Variable Polarization Undulator for SOLEIL undulator, polarization, permanent-magnet, multipole 4242
  • B. Diviacco, R. Bracco, C. Knapic, D. Millo, D.Z. Zangrando
    ELETTRA, Basovizza, Trieste
  • O.V. Chubar, A. Dael, M. Massal
    SOLEIL, Gif-sur-Yvette
  • Z. Martí
    LLS, Bellaterra (Cerdanyola del Vallès)
  Two variable polarization undulators (HU80) are being designed and constructed in the framework of an ELETTRA-SOLEIL collaboration. The four-quadrant permanent magnet structure, of the APPLE-II type, will produce various polarization modes by means of parallel or anti-parallel displacement of two diagonally opposite magnet arrays. In this paper the main aspects of the magnetic and mechanical design will be summarized. The post-assembly field quality optimization methods will be described in some detail, discussing our approach to the correction of phase, trajectory and multipole errors. Finally the magnetic measurement results on the completed device will be presented.  
TOAC001 Overview of Impedance and Single-Beam Instability Mechanisms impedance, coupling, damping, octupole 14
  • E. Métral
    CERN, Geneva
  Single-bunch and coupled-bunch instability mechanisms will be reviewed in both longitudinal and transverse planes. The resistive-wall impedance will be discussed in the particular case of the LHC collimators, which reveal a new physical regime. Stabilization by Landau damping, feedbacks, or linear coupling between the transverse planes will also be treated. Benchmarking of analytical predictions with some instability codes will be shown as well as several experimental results.  
TOAC002 Beam Loading Compensation for Super B-Factories feedback, impedance, beam-loading, storage-ring 154
  • D. Teytelman
    SLAC, Menlo Park, California
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

Super B-factory designs under consideration expect to reach luminosities in the 1035 - 1036 range. The dramatic luminosity increase relative to the existing B-factories is achieved, in part, by raising the beam currents stored in the electron and positron rings. For such machines to succeed it is necessary to consider in the RF system design not only the gap voltage and beam power, but also the beam loading effects. The main effects are the synchronous phase transients due to the uneven ring filling patterns and the longitudinal coupled-bunch instabilities driven by the fundamental impedance of the RF cavities. A systematic approach to predicting such effects and for optimizing the RF system design will be presented. Existing as well as promising new techniques for reducing the effects of heavy beam loading will be described and illustrated with examples from the existing storage rings including PEP-II, KEKB, and DAFNE.

TOAC003 Stochastic Cooling for Bunched Beams ion, kicker, pick-up, heavy-ion 310
  • M. Blaskiewicz
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. DOE.

A longitudinal stochastic cooling system for RHIC is under construction and partial commissioning is planned for the upcoming run. The state of the system and future plans are discussed.

TOAC005 Coherent Synchrotron Radiation as a Diagnostic Tool for the LCLS Longitudinal Feedback System radiation, feedback, electron, synchrotron-radiation 428
  • J. Wu, P. Emma, Z. Huang
    SLAC, Menlo Park, California
  Funding: Work is supported by the US Department of Energy under contract DE-AC02-76SF00515.

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL). To ensure the vitality of FEL lasing, a longitudinal feedback system is required together with other diagnostics. In this paper, we study the possibility of using Coherent Synchrotron Radiation (CSR) from the chicane as the diagnostic tool for bunch length feedback. Calculations show that CSR is a good candidate, even for the non-Gaussian, double-horn longitudinal charge distribution. We further check the feasibility for low and high charge options, and also the possibility for detecting the microbunching.

TOAA009 Recent Test Results of the Fast-Pulsed 4 T COSO Dipole GSI 001 dipole, coupling, sextupole, injection 683
  • G. Moritz, J. Kaugerts
    GSI, Darmstadt
  • B. Auchmann, S. Russenschuck, R. de Maria
    CERN, Geneva
  • J. Escallier, G. Ganetis, A.K. Jain, A. Marone, J.F. Muratore, R.A. Thomas, P. Wanderer
    BNL, Upton, Long Island, New York
  • M. Wilson
    Oxford Instruments, Accelerator Technology Group, Oxford, Oxon
  For the FAIR-project at GSI a model dipole was built at BNL with the nominal field of 4 T and a nominal ramp rate of 1 T/s. The magnet design was similar to the RHIC dipole with some changes for loss reduction and better cooling. The magnet was already successfully tested in a vertical cryostat with good training behaviour. Cryogenic losses were measured and first results of field harmonics were published. However, for a better understanding of the cooling process quench currents at several ramp rates were investigated. Detailed measurements of the field harmonics at different ramp rates and at several cycles were performed. To separate the effects of the coil and the iron yoke the magnet was disassembled and tested as collared coil only. Recent test results will be presented.  
TPAE042 Beam Matching to a Plasma Wake Field Accelerator Using a Ramped Density Profile at the Plasma Boundary plasma, emittance, focusing, ion 2702
  • K.A. Marsh, C.E. Clayton, C. Huang, D.K. Johnson, C. Joshi, W. Lu, W.B. Mori, M. Zhou
    UCLA, Los Angeles, California
  • C.D. Barnes, F.-J. Decker, M.J. Hogan, R.H. Iverson, P. Krejcik, C.L. O'Connell, R. Siemann, D.R. Walz
    SLAC, Menlo Park, California
  • S. Deng, T.C. Katsouleas, P. Muggli, E. Oz
    USC, Los Angeles, California
  Funding: DOE Grant No. DE-FG03-92ER40727.

An important aspect of plasma wake field accelerators (PWFA) is stable propagation of the drive beam. In the under dense regime, the drive beam creates an ion channel which acts on the beam as a strong thick focusing lens. The ion channel causes the beam to undergo multiple betatron oscillations along the length of the plasma. There are several advantages if the beam size can be matched to a constant radius. First, simulations have shown that instabilities such as hosing are reduced when the beam is matched. Second, synchrotron radiation losses are minimized when the beam is matched. Third, an initially matched beam will propagate with no significant change in beam size in spite of large energy loss or gain. Coupling to the plasma with a matched radius can be difficult in some cases. This paper shows how an appropriate density ramp at the plasma entrance can be useful for achieving a matched beam. Additionally, the density ramp is helpful in bringing a misaligned trailing beam onto the drive beam axis. A plasma source with boundary profiles useful for matching has been created for the PWFA experiments at SLAC.

TPAT006 Impact of Optics on CSR-Related Emittance Growth in Bunch Compressor Chicanes emittance, optics, shielding, space-charge 1015
  • T. Limberg, M. Dohlus
    DESY, Hamburg
  The dependence of emittance growth due to Coherent Synchrotron Radiation (CSR) in bunch compressor chicanes on optics has been noticed and empirically studied in the past. We revisit the subject, suggesting a model to explain slice emittance growth dependence on chicane optics. A simplified model to calculate projected emittance growth when it is mainly caused by transverse slice centroid offsets is presented. It is then used to find optimal compensation of centroid kicks in the single chicanes of a two-stage compression system by adjusting the phase advance of the transport in between and the ration of the compression factors.  
TPAT015 Simulations of Error-Induced Beam Degradation in Fermilab's Booster Synchrotron booster, emittance, space-charge, simulation 1458
  • P.S. Yoon
    Rochester University, Rochester, New York
  • C.L. Bohn
    Northern Illinois University, DeKalb, Illinois
  • W. Chou
    Fermilab, Batavia, Illinois
  Funding: Work supported by the University Research Association, Inc. under U.S. Department of Energy (DOE) contract No. DE-AC02-76-CH03000, and by DOE grant No. DE-FG02-04ER41323 to NIU, and by DOE grant No. DE-FG02-91ER40685 to University of Rochester.

Individual particle orbits in a beam will respond to both external focusing and accelerating forces as well as internal space-charge forces. The external forces will reflect unavoidable systematic and random machine errors, or imperfections, such as jitter in magnet and radio-frequency power supplies, as well as magnet translation and rotation alignment errors. The beam responds in a self-consistent fashion to these errors; they continually do work on the beam and thereby act as a constant source of energy input. Consequently, halo formation and emittnace growth can be induced, resulting in beam degradation and loss. We have upgraded the ORBIT-FNAL package and used it to compute effects of machine errors on emittance dilution and halo formation in the existing FNAL-Booster synchrotron. This package can be applied to study other synchrotrons and storage rings, as well.

TPAT017 Transverse Impedance of Elliptical Tapers impedance, vacuum, resonance, undulator 1535
  • B. Podobedov, S. Krinsky
    BNL, Upton, Long Island, New York
  Funding: Work supported by the U.S. DOE.

The geometric impedance of small-gap undulator chambers is of paramount importance for modern light sources because it may drive transverse single bunch instabilities. Analytical expressions are derived for the transverse impedance assuming a slowly tapered vacuum chamber with a confocal elliptical cross-section. The analytical results are confirmed by numerical simulations with the GdfidL Electromagnetic Field simulator and they yield the correct asymptotic limits for both round and flat chambers.

TPAT018 Stability of Barrier Buckets with Short or Zero Barrier Separations resonance, quadrupole, dipole, beam-losses 1589
  • K.Y. Ng
    Fermilab, Batavia, Illinois
  A barrier bucket with small separation between the rf barriers (relative to the barrier widths) or even zero separation has its synchrotron tune decreasing rather slowly towards the boundary of the bucket. As a result, large area at the bucket edges can become unstable under the modulation of rf voltage and rf phase. Application is made to those barrier buckets used in the process of momentum mining on the issues of bunch-distribution distortion and particle loss.  
TPAT035 Coherent Synchrotron Radiation from an Electron Beam in a Curved Waveguide electron, radiation, emittance, simulation 2390
  • D.R. Gillingham, T. M. Antonsen, P.G. O'Shea
    IREAP, College Park, Maryland
  Funding: Research supported by the office of Naval Research and the Joint Technology Office.

The radiation emitted by a pulsed electron beam as it travels on a circular trajectory inside a waveguide is calculated using a 3D simulation. Forward-propagating wave equations for the fields in the waveguide are calculated by a perturbation of the Maxwell equations where the radius of curvature is large compared to the dimensions of the waveguide. These are integrated self-consistently with the distribution of charge in the beam to provide the complete fields (electric and magnetic) for all times during the passage of the beam through the waveguide and therefore are applicable to sections of any length or combinations thereof. The distribution of electrons and their momentum are also modified self-consistently so that the results may be used to estimate the effect of the radiation on the beam quality (emittance and energy spread).

TPAT042 Progress on a Vlasov Treatment of Coherent Synchrotron Radiation from Arbitrary Planar Orbits synchrotron-radiation, emittance, radiation, lattice 2699
  • G. Bassi, J.A. Ellison
    UNM, Albuquerque, New Mexico
  • R.L. Warnock
    SLAC, Menlo Park, California
  Funding: Support from DOE grants DE-AC02-76SF00515 and DE-FG02-99ER1104 is gratefully acknowledged.

We study the influence of coherent synchrotron radiation (CSR) on particle bunches traveling on arbitrary planar orbits between parallel conducting plates (shielding). The time evolution of the phase space distribution is determined by solving the Vlasov-Maxwell equations in the time domain. This provides lower numerical noise than the macroparticle method, and allows the study of emittance degradation and microbunching in bunch compressors. We calculate the fields excited by the bunch in the lab frame using a formula simpler than that based on retarded potentials.* We have developed an algorithm for solving the Vlasov equation in the beam frame using arc length as the independent variable and our method of local characteristics (discretized Perron-Frobenius operator).We integrate in the interaction picture in the hope that we can adopt a fixed grid. The distribution function will be represented by B-splines, in a scheme preserving positivity and normalization of the distribution. The transformation between lab and beam frame is carefully treated. Here we report on our implementation of the algorithm for a chicane bunch compressor with linear energy chirp and take steps to treat the nonlinear case.

*"Vlasov Treatment of Coherent Synchrotron Radiation from Arbitrary Planar Orbits" to be published in the Proceedings of ICAP04, St. Petersburg, R. Warnock, G. Bassi and J. A. Ellison.

TPAT057 Observations of UHF Oscillations in the IPNS RCS Proton Bunch quadrupole, acceleration, proton, extraction 3375
  • J.C. Dooling, F.R. Brumwell, G.E. McMichael, S. Wang
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy under contract no. W-31-109-ENG-38.

The Intense Pulsed Neutron Source (IPNS) Rapid Cycling Synchrotron (RCS) accelerates 3.2x 1012 protons from 50 MeV to 450 MeV in a single bunch (h=1) at 30 Hz. The rf frequency varies from 2.21 MHz to 5.14 MHz during the 14.2 ms acceleration interval. To maintain stability of the bunch, phase modulation is introduced to the rf at approximately twice the synchrotron frequency (synchrotron tune is 0.0014). This phase modulation causes a parametric quadrupole oscillation to develop in the bunch, and as this occurs, the bunch spectrum shows a significant increase in high frequency content. Without phase modulation, the beam experiences an instability which results in the loss of a large fraction of the charge 2-4 ms prior to extraction. It is unclear if the stability imparted to the beam by phase modulation comes from the quadrupole oscillation or from the high frequency excitation. A longitudinal tracking code is presently being modified to include amplitude and phase modulation of the bunch. The numerical analysis will be used to compare growth rates with those observed in the machine. The results of this analysis will be important as we introduce second harmonic rf with a new third cavity in the RCS later in 2005.

TPAT065 Damping Transverse Instabilities in the Tevatron Using AC Chromaticity simulation, proton, sextupole, damping 3665
  • V.H. Ranjbar
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the U.S. Department of Energy.

Several papers*,** have suggested possibility of using varying chromaticity to damp the head-tail instability. We test this by cycling the chromaticity sextupole magnets in the Tevatron near the synchrotron frequency to see if the head-tail stability threshold is increased. Further we compare the turn-by-turn evolution of a bunch slice in the presence of varying chromaticity to a model previously developed.

*W.-H. Cheng, A. M. Sessler, and J. S. Wurtele, Phys. Rev. Lett. 78, 4565 (1997). **T. Nakamura in Proceedings of the 1995 IEEE Particle Accelerator Conference (IEEE, Dallas, 1995), Vol. 5, p. 3100.

TPAT085 Development of a Beam-Beam Simulation Code for e+e- Colliders simulation, luminosity, beam-beam-effects, positron 4176
  • Y. Zhang
    IHEP Beijing, Beijing
  • K. Ohmi
    KEK, Ibaraki
  Funding: Chinese National Foundation of Natural Sciences, contract 10275079 JSPS Core University Program

BEPC will be upgraded into BEPCII, and the luminosity will be about 100 times higher. We developed a three dimensional strong-strong PIC code to study the beam-beam effects in BEPCII. The transportation through the arc is the same as that in Hirata's weak-strong code. The beam-beam force is computed directly by solving the Poisson equation using the FACR method, and the boundary potential is computed by circular convolution. The finite bunch length effect is included by longitudinal slices. An interpolation scheme is used to reduce the required slice number in simulations. The standard message passing interface (MPI) is used to parallelize the code. The computing time increases linearly with (n+1), where n is the slice number. The calculated luminosity of BEPCII at the design operating point is less than the design value. The best area in the tune space is near (0.505,0.57) according to the survey, where the degradation of luminosity can be improved.

TPAT096 Focusing-Free Transition Crossing in RHIC using Induction Acceleration induction, acceleration, beam-losses, emittance 4314
  • K. Takayama, Y. Shimosaki, K. Torikai
    KEK, Ibaraki
  • J. Wei
    BNL, Upton, Long Island, New York
  Focusing-free transition crossing (FFTC) in RHIC is proposed. The original idea of FFTC proposed by J.Griffin was tried in the FNAL 500GeV main ring, where a gradient in the acceleration voltage was smoothed flat by introducing multi higher-harmonic RF. If the longitudinal focusing disappears during a limited time period near TC, various undesired features, such as bunch shortening and elongation in the momentum space, should be mitigated. In present RHIC operation, the slow ramping across transition leads into complications of nonlinear chromatic effects, vacuum pressure rise, instability, and transition-jump related lattice distortions. Recently, induction acceleration of a single RF bunch has been successfully demonstrated in KEK-PS,* where a proton bunch is trapped by the existing RF and accelerated with an induction step-voltage to 8 GeV. The utilized acceleration device is capable of generating a step voltage of 2 kV/cell at most at an arbitrary repetition rate up to 1 MHz. We here propose focusing-free TC in RHIC, introducing similar devices. In this scheme, the RF voltage is tuned off during an optimized time-period of several tens of ms, and the required acceleration voltage is provided as an induction flat-voltage.

*K.Takayama et al., submitted to Phys. Rev. Lett., http://www.arxiv.org/pdf/physics/0412006.

TOAB010 Research and Development of Variable Polarization Superconducting Undulator at the NSLS undulator, polarization, radiation, photon 734
  • S. Chouhan, D.A. Harder, G. Rakowsky, J. Skaritka, T. Tanabe
    BNL, Upton, Long Island, New York
  Funding: Office Of Science.

In this work a new concept for the construction of planar variable polarization superconductive insertion device is presented. The construction of the device with 8 mm gap and magnetic period of 26 mm is described compared with permanent magnet insertion device with the same gap & period length, as well as with previously published concepts. Advantage of this design include: (1) electrical tunability for both right and left circular and elliptical, as well as linear vertical or horizontal, (2) it requires no compensation of unwanted vertical field component and (3) used only simple windings of superconductive wire in an interlaced pattern. As a first step towards the construction of full-length device we propose to build & test a short prototype that will serve as a proof of the concept for versatile variable polarization superconductor magnet.

TOPC003 Beam Measurements and Upgrade at BL 7.2, the Second Diagnostics Beamline of the Advanced Light Source radiation, synchrotron-radiation, emittance, diagnostics 281
  • T. Scarvie, A. Biocca, N. Kelez, M.C. Martin, T. Nishimura, G.J. Portmann, F. Sannibale, E. Williams
    LBNL, Berkeley, California
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

Beamline BL 7.2 of the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory is a beam diagnostics system that uses the synchrotron radiation (SR) emitted by a dipole magnet. It consists of two branches, in the first one the x-ray portion of the SR is used in a pinhole camera system for measuring the transverse profile of the beam. The second branch is equipped with a x-ray BPM system and with a multipurpose port where the visible and the infrared part of the SR can be used for various applications such as bunch length measurements and IR coherent synchrotron radiation experiments. The pinhole system has been commissioned at the end of 2003 and since then is in successful operation. The installation of the second branch has been completed recently and the results of its commissioning are presented in this paper together with examples of beam measurements performed at BL 7.2.

TPPE054 Status of the Injection System for the Australian Synchrotron Project booster, injection, quadrupole, sextupole 3271
  • S.P. Møller, H. Bach, F. Bødker, T.G. Christiansen, A. Elkjaer, S. Friis-Nielsen, N. Hauge, J. Kristensen, L.K. Kruse, S.P. Møller, B.R. Nielsen
    Danfysik A/S, Jyllinge
  DANFYSIK A/S designs and builds the complete injection system for the Australian Synchrotron Project. The full-energy booster will accelerate the beam from the injection energy of 100 MeV. to a maximum of 3.0 GeV. The booster is using combined function magnets. The status of the project is presented.  
TPPP013 Simulations of Parametric Resonance Ionization Cooling of Muon Beams simulation, resonance, focusing, lattice 1321
  • K. Beard, S.A. Bogacz, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • R.P. Johnson, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
  • K. Yonehara
    Illinois Institute of Technology, Chicago, Illinois
  Funding: This work was supported in part by DOE SBIR grants DE-FG02-03ER83722, and 04ER84016.

The technique of using a parametric resonance to allow better ionization cooling is being developed to create small beams so that high collider luminosity can be achieved with fewer muons. In the linear channel that is studied in this effort, a half integer resonance is induced such that the normal elliptical motion of particles in x-x' phase space becomes hyperbolic, with particles moving to smaller x and larger x' as they pass down the channel. Thin absorbers placed at the focal points of the channel then cool the angular divergence of the beam by the usual ionization cooling mechanism where each absorber is followed by RF cavities. Thus the phase space of the beam is compressed in transverse position by the dynamics of the resonance and its angular divergence is compressed by the ionization cooling mechanism. We report the first results of simulations of this process, including comparisons to theoretical cooling rates and studies of sensitivity to variations in absorber thickness and initial beam conditions.

TPPP026 Bunch-Length Measurements in PEP-II single-bunch, positron, electron, luminosity 1934
  • A.S. Fisher, A. Novokhatski, J.L. Turner, U. Wienands, G. Yocky
    SLAC, Menlo Park, California
  • R. Holtzapple
    Alfred University, Alfred, New York
  Funding: Supported by U.S. Department of Energy contract DE-AC03-76SF00515.

We measured the lengths of colliding e+e- bunches in the PEP-II B Factory at SLAC using various techniques. First, at several RF voltages and with both single-bunch and multibunch beams, a synchroscan streak camera measured synchrotron emission through a narrow blue filter. With 3.8 MV of RF, the length of a single positron bunch was 12 mm at low current, rising to 13 mm at 1.5 mA and 14.8 mm at 3 mA. The electrons measured 12.2 mm with little current dependence. Both are longer than the expected low-current value of 10 mm (e+) and 11 mm (e-), derived from the energy spread and the measured synchrotron tune. We also determined the length from measurements between 2 and 13 GHz of the bunch spectrum on a BPM button. After correcting for the frequency dependence of cable attenuation, we then fit the measured spectrum to that of a Gaussian bunch. With 3.8 MV, the positrons measurement gave 13.2 mm at 1.5 mA/bunch in a full ring, in agreement with the streak camera, but we found 11.4 mm for the electrons at 16.7 MV and 1 mA/bunch, lower than the streak measurement.

TPPP029 A Preliminary Interaction Region Design for a Super B-Factory background, luminosity, radiation, interaction-region 2077
  • M.K. Sullivan, M.H. Donald, S. Ecklund, A. Novokhatski, J. Seeman, U. Wienands
    SLAC, Menlo Park, California
  • M.E. Biagini
    INFN/LNF, Frascati (Roma)
  Funding: work supportted by the Department of Energy under contract number DE-AC03-76SF00515.

The success of the two B-Factories (PEP-II and KEKB) has encouraged us to look at design parameters for a B-Factory with a 30-50 times increase in the luminosity of the present machines (L~1e36). In order to achieve this high luminosity, the beta y* values are reduced to 3-2 mm, the bunch spacing is minimized (0.6-0.3 m) and the bunch currents are increased. Total beam currents range from 5-25 A. The interaction region (IR) of these "SuperB" designs presents special challenges. Synchrotron radiation fans from local bending in shared magnets and from upstream sources pose difficulties due to the high power levels in these fans. High-order-mode(HOM)heating, effects that have been seen in the present B-factories, will become much more pronounced with the very short bunches and high beam currents. Masking the detector beam pipe from synchrotron radiation must take into account effects of HOM power generation. Backgrounds that are a function of the luminosity will become very important. We present an initial design of an IR with a crossing angle of ± 14 mrad and include a discussion of the constraints, requirements and concerns that go into designing an IR for these very high luminosity e+e- machines.

TPPP042 Synchrotron Radiation in eRHIC Interaction Region radiation, photon, synchrotron-radiation, interaction-region 2729
  • J. Beebe-Wang, C. Montag
    BNL, Upton, Long Island, New York
  • A. Deshpande
    Stony Brook University, Stony Brook
  • D.J. Rondeau
    Binghamton University, State University of New York, Binghamton, New York
  • B. Surrow
    MIT, Cambridge, Massachusetts
  Funding: Work performed under the auspices of the US DOE.

The eRHIC currently under study at BNL consists of an electron storage ring added to the existing RHIC complex. The interaction region of this facility has to provide the required low-beta focusing while accommodating the synchrotron radiation generated by beam separation close to the interaction point. In the current design, the synchrotron radiation caused by 10GeV electrons bent by low-beta triplet magnets will be guided through the interaction region and dumped 5m downstream. However, it is unavoidable to stop a fraction of the photons at the septum where the electron and ion vacuum system are separated. In order to protect the septum and minimize the backward scattering of the synchrotron radiation, an absorber and collimation system will be employed. In this paper, we first present the overview of the current design of the eRHIC interaction region with special emphasis on the synchrotron radiation. Then the initial design of the absorber and collimation system, including their geometrical and physical properties, will be described. Finally, our initial investigation of synchrotron radiation in the eRHIC interaction region, especially a simulation of the backward scattering from the absorber, will be presented.

TPPP044 Interaction Region Design for the Electron-Light Ion Collider ELIC electron, synchrotron-radiation, quadrupole, radiation 2824
  • C. Montag
    BNL, Upton, Long Island, New York
  • S.A. Bogacz, Y.S. Derbenev, L. Merminga
    Jefferson Lab, Newport News, Virginia
  Funding: Work performed under the auspices of the US Department of Energy.

The Electron-Light Ion Collider ELIC proposed by Jefferson Lab aims at very high luminosities for collisions of 150 GeV protons on 7 GeV electrons. To achieve these high luminosities, very strong low-beta focusing of low-emittance beams is required. Taking advantage of the unequal design proton beam emittances in the two transverse planes, an interaction region design based on superconducting quadrupole doublets has been deveoped. Compared with the original design, this scheme provides larger beam apertures at lower magnetic fields, while potentially doubling the luminosity.

TPPP045 Interaction Region Design for the Electron-Ion Collider eRHIC electron, radiation, interaction-region, synchrotron-radiation 2893
  • C. Montag, B. Parker, S. Tepikian
    BNL, Upton, Long Island, New York
  • D. Wang
    MIT, Middleton, Massachusetts
  Funding: Work performed under the auspices of the U.S. Department of Energy.

To facilitate the study of collisions between 10 GeV polarized electrons and 100 GeV/u heavy ions or 250 GeV polarized protons at high luminosities, adding a 10 GeV electron storage ring to the existing RHIC complex has been proposed. The interaction region of this electron-ion collider eRHIC has to provide the required low-beta focusing, while simultaneously accomodating the synchrotron radiation fan generated by beam separation close to the interaction point, which is particularly challenging. The latest design status of the eRHIC interaction region is presented.

TPPT014 Induction System for a Proton Bunch Acceleration in Synchrotron induction, acceleration, proton, power-supply 1398
  • K. Torikai, Y.A. Arakida, J. Kishiro, T. Kono, E. Nakamura, Y. Shimosaki, K. Takayama, T. Toyama, M. Wake
    KEK, Ibaraki
  Funding: The project is officially supported by Grant-In-Aid for Creative Scientific Research (KAKENHI 15GS0217, 5 years term).

An induction cavity capable of operating at a repetition rate of 1MHz with a 50% duty has been built and employed for the first induction acceleration of a proton bunch from 500MeV to 8GeV in the KEK-PS.* In this experiment, an acceleration voltage of 4.7kV and an repetition frequency of 667kHz-882kHz were required. The installed induction device consists of three induction cells, each of which can generate a bipolar induction voltage of a maximum output voltage of 2 kV with a flat-top of 300ns and a 25ns rising/falling time. Electrical characteristics of the cavity itself, such as inductance, capacitance, and resistance, have been evaluated in three independent ways: (1) excitation due to a small signal from a network analyzer, (2) excitation by a proton beam as a primary driver, (3) excitation with a actual pulse modulator in an entire system. This paper will compare these results as well as theoretical design values. A general design procedure for an induction acceleration cavity will be given.

*K.Takayama et al., submitted to Phys. Rev. Lett. http://www.arxiv.org/pdf/physics/0412006.

TPPT042 The Simulation Calculations and Dielectric Characteristics Investigation of an X-Band Hybrid Dielectric-Iris-Loaded Traveling Accelerating Structure simulation, acceleration, resonance, synchrotron-radiation 2720
  • C.-F. Wu, S. Dong, S. Hongbing, D. Jia, H. Lin, L. Wang
    USTC/NSRL, Hefei, Anhui
  Funding: This work is supported by the National Natural Science Foundation of China(No.10375060,10205014)and the Project of Knowledge Innovation Program of the Chinese Academy of Sciences.

Mafia code has been used to calculate the RF properties versus the geometric parameters and dielectric permittivity for the X-band (f=9.37GHz) hybrid dielectric-iris-loaded traveling accelerating structure. The simulation results show that when the range of the permittivity is about 5-9, the new structure may have lower ratio (about 1) of peak surface electric field at the iris to axial accelerating electric field by optimizing the geometric parameters, while r, Q, r/Q of the new structure being comparable to iris-loaded accelerating structure. The experimental investigations of the permittivity of the ceramics have been made at the X-band by using the cavity perturbation technique. The measured results are in good agreement with the simulation results of Microwave Studio. Furthermore, the stability of the ceramics is examined. A number of experimental results show that the certain ceramic with permittivity of 5.78 is applied to the design of the new accelerating structure.

TPPT043 The Studies of Hybrid Dielectric-Iris-Loaded Accelerating Structure acceleration, synchrotron-radiation, simulation, impedance 2747
  • C.-F. Wu, S. Dong, H. Lin
    USTC/NSRL, Hefei, Anhui
  Funding: This work is supported by the National Natural Science Foundation of China(No.10375060,10205014) and the Project of Knowledge Innovation Program of the Chinese Academy of Sciences.

The dispersion property and the propagation characteristics of the accelerating mode (TM01 mode) and higher-order-modes about a new hybrid dielectric-iris-loaded accelerating structure have been analysed and discussed by the field matching method. Mafia code has been used to calculate the RF properties versus the geometric parameters and dielectric permittivity for the X-band (f=9.37GHz) hybrid dielectric-iris-loaded traveling accelerating structure. Some model cavities have been developed, and experimental investigations have been carried on. The above results will provided some beneficial datum for the design and manufacture of X-band hybrid dielectric-iris-loaded traveling-wave accelerating structure.

TPPT049 Design and Cold Model Test of 500MHz Damped Cavity for ASP Storage Ring RF System impedance, damping, coupling, storage-ring 3076
  • J. Watanabe, K. Nakayama, K. S. Sato, H. Suzuki
    Toshiba, Yokohama
  • M. Izawa
    KEK, Ibaraki
  • A. Jackson, G. LeBlanc, K. Zingre
    ASP, Clayton, Victoria
  • T. Koseki
    RIKEN/RARF/CC, Saitama
  • N. Nakamura, H. Sakai, H. Takaki
    ISSP/SRL, Chiba
  TOSHIBA is constructing the storage ring RF system for the Australian Synchrotron Project(ASP). Two pairs of the 500MHz Higher Order Mode(HOM) damped cavities will be applied for this system. The cavities are modified KEK-PF type with silicon-carbide(SiC) microwave absorber and added three HOM anttenas for damping the longitudinal HOM impedance less than 20kOhm/GHz to meet requirement of ASP specification. The shunt impedance has been improved more than 5% in comparison with the original design by reducing the beam bore diameter without degrading HOM damping capability. The design of the cavity and the test results of an Al cold model are described.  
TPPT057 Quality Control of the Electro Polishing Process at DESY superconductivity, power-supply, ion 3369
  • N. Steinhau-Kuehl, A. Matheisen, B. Meyer, B. Petersen, ms. Schmoekel
    DESY, Hamburg
  Funding: Supported by the European Community Research activity Care under the FP 6 program(RII3-CT-2003-506395).

The technology of electro-polishing of super-conducting resonators made from Niobium is foreseen as basic surface preparation technology for the Xfel accelerator project at DESY. Here about 1000 resonators will be build and installed into the accelerator section. For an industrial application of this technique a quality control has to be developed and established.A method to control the acid quality and improve the life time of the acid is under development. We report on the test setup and measurements done on samples and the implementation of this quality control to the DESY electro polishing process.

TPPT060 Design of a Multi-Cell, HOM Damped Superconducting Cavity for the Strong RF Focusing Experiment at DAFNE coupling, focusing, factory, feedback 3505
  • A. Gallo, D. Alesini, C. Biscari, R. Boni, F. Marcellini, M. Zobov
    INFN/LNF, Frascati (Roma)
  • C. Pagani
    DESY, Hamburg
  A strong RF focusing experiment to be performed at the DAFNE Phi-factory has been proposed to create and observe a bunch length modulation along the ring. The very large RF gradient required to reach the strong focusing regime can only be obtained by using a multi-cell superconducting cavity. Moreover, in order to demonstrate the feasibility of a high luminosity collider based on this principle, a total multibunch current of the order of 1A has to be stored under stable conditions in this regime. A 1.3 GHz 7-cells cavity has been designed for this purpose, based on the TESLA geometry with small modifications of the basic cell to comply with the DAFNE revolution frequency. The number of cells has been changed from 9 to 7 to reduce the number of the cavity HOMs, while the beam tubes have been enlarged to let most of the HOMs propagate and be damped by room-temperature ferrite rings. The modes of the first longitudinal band, which include the accelerating TM010_pi, do not propagate in the beam tubes and have been studied with special care to prevent the overlap with the bunch revolution harmonics and to cure the effects of coupling to the synchrotron tune sidebands.  
TPPT066 Successful Operation of the 500 MHz SRF Module at TLS electron, photon, klystron, injection 3706
  • C. Wang, L.-H. Chang, S.-S. Chang, C.-T. Chen, F.-T. Chung, F.-Z. Hsiao, G.-Y. Hsiung, K.-T. Hsu, C.-C. Kuo, H.C. Li, M.-C. Lin, R.J. Lin, Y.K. Lin, G.-H. Luo, M.H. Tsai, J.Y. Yang, T.-T. Yang, M.-S. Yeh
    NSRRC, Hsinchu
  A superconducting radio frequency (SRF) cavity of CESR-III design was installed sucessfully in the electron storage ring at the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. The project goals are to double the photon flux by raising the electron beam current and to increase the beam stability by taking advantage of the well-damped high-order modes of SRF cavity. Nowadays, SRF cavity has become the key technology for new synchrotron light sources under construction or planning worldwide. The first operational experience of the SRF cavity at the NSRRC will be presented.  
TPPT089 Commissioning and Operations Results of the Industry-Produced CESR-Type SRF Cryomodules storage-ring, superconducting-RF, vacuum, klystron 4233
  • S.A. Belomestnykh, R.P.K. Kaplan, H. Padamsee, P. Quigley, J.J.R. Reilly, J. Sears, V. Veshcherevich
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • S. Bauer, M. Pekeler, H. Vogel
    ACCEL, Bergisch Gladbach
  • L.-H. Chang, C.-T. Chen, F.-Z. Hsiao, M.-C. Lin, G.-H. Luo, C. Wang, T.-T. Yang, M.-S. Yeh
    NSRRC, Hsinchu
  • E. Matias, J. Stampe, M.S. de Jong
    CLS, Saskatoon, Saskatchewan
  Funding: Work is partially supported by the National Science Foundation.

Upon signing a technology transfer agreement with Cornell University, ACCEL began producing turn-key 500 MHz superconducting cavity systems. Four such cryomodules have been delivered, commissioned and installed in accelerators for operation to date. Two more cryomodules are scheduled for testing in early 2005. One of them will be put in operation at Canadian Light Source (CLS); the other will serve as a spare at Taiwan Light Source (TLS). The commissioning results and operational experience with the cryomodules in CESR, CLS and TLS are presented.

WPAE002 Safety Management for the Cryogenic System of Superconducting RF System controls, vacuum, storage-ring, superconducting-RF 832
  • S.-P. Kao, C.R. Chen, F.-Z. Hsiao, J.P. Wang
    NSRRC, Hsinchu
  The installation of the helium cryogenic system for the superconducting RF cavity and magnet were finished in the National Synchrotron Radiation Research Center (NSRRC) at the end of October 2002. The first phase of this program will be commissioned at the end of 2004. This was the first large scale cryogenic system in Taiwan. The major hazards to personnel are cryogenic burn and oxygen deficient. To avoid the injury of the operators and meet the requirements of local laws and regulations, some safety measures must be adopted. This paper will illustrate the methods of risk evaluation and the safety control programs taken at NSRRC to avoid and reduce the hazards from the cryogenic system of the superconducting RF cavity and magnet system.  
WPAE003 The Cryogenic Supervision System in NSRRC synchrotron-radiation, radiation 844
  • H.C. Li, S. H. Chang, W. S. Chiou, F.-Z. Hsiao, Z.-D. Tsai
    NSRRC, Hsinchu
  The helium cryogenic system in NSRRC is a fully automatic PLC system using the Siemens SIMATIC 300 controller. Modularization in both hardware and software makes it easy in the program reading, the system modification and the problem debug. Based on the Laview program we had developed a supervision system taking advantage of the Internet technology to get system’s real-time information in any place. The functions of this supervision system include the real-time data accessing with more than 300 digital/analog signals, the data restore, the history trend display, and the human machine interface. The data is accessed via a Profibus line connecting the PLC system and the supervision system with a maximum baud rate 1.5 Mbit/s. Due to this supervision system, it is easy to master the status of the cryogenic system within a short time and diagnose the problem.  
WPAE012 Gamma-Ray Irradiation Experiments of Collimator Key Components for the 3GeV-RCS of J-PARC radiation, beam-losses, vacuum, proton 1309
  • M. Kinsho, F. Masukawa, N. Ogiwara, O. Takeda, K. Yamamoto
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • J. Kusano
    Japan Atomic Energy Institute, Linac Laboratory, Tokai-Mura
  The turbo molecular pump and the stepping motor which can be operated exposed to high radiation has been under development at JAERI for use in the 3GeV-RCS of the J-PARC. In order to determine the extent of radiation damage to those instruments, gamma-ray irradiation testing was performed at JAERI. It was succeed that the turbo molecular pump and stepping motor could operate properly when given an absorption dose more than 15 MGy in a gamma-ray irradiation environment.  
WPAE015 High Heat-Load Slits for the PLS Multipole Wiggler wiggler, multipole, storage-ring, synchrotron-radiation 1449
  • K.H. Gil, J.Y. Choi, C.W. Chung, Y.-C. Kim, H.-S. Lee
    PAL, Pohang, Kyungbuk
  The HFMX (High Flux Macromolecular X-ray crystallography) beamline under commissioning at Pohang Accelerator Laboratory uses beam from a multipole wiggler for MAD experiment. Two horizontal and vertical slits relevant to high heat load are installed at its front-end. In order to treat high heat load and to reduce beam scattering, the horizontal slit has two glidcop blocks with 10° of vertical inclination and its tungsten blades defining beam size are bolted on backsides of both blocks. The blocks of the slit are adjusted on fixed slides by two actuating bars, respectively. Water through channels machined along the actuating bars cool down the heat load of both blocks. The vertical slit has the same structure as the horizontal slit except its installation direction and angle of vertical inclination. The installed slits show stable operation performance and no alignment for the blocks is required by virtue of a pair of blocks translating on slides. The cooling performance of two slits is also shown to be acceptable. In this article, the details of the design and manufacture of the two slits are presented and its operation performance is reported.  
WPAE016 Development of a Precision Amplifier for the Detector synchrotron-radiation, radiation, feedback, ion 1514
  • K.-H. Park, C.W. Chung, S.-M. Hong, S.-H. Jeong, Y.G. Jung, D.E. Kim, H.-S. Lee, W.W. Lee
    PAL, Pohang, Kyungbuk
  • B.-K. Kang
    POSTECH, Pohang, Kyungbuk
  A high gain trans-resistance amplfier has been developed for measuring the intensity of synchrotron radiation at Pohang Light Source(PLS). This amplifier built with discrete elements and operational amplifiers.It had the capability of measuring range from 1pA to 1 uA with good linearity. A microprocessor was also installed to interface the amplifier with the computer, and controlled the other sub-circuits. The various characteristics of amplifier such as linearity, sensitivity,stability, etc. have been investigated, and its experimental results carried out at the beam line are presented in this paper.  
WPAE025 Design for a 1.3 MW, 13 MeV Beam Dump for an Energy Recovery Linac vacuum, electron, injection, linac 1877
  • C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  • Y. He, C.H. Smith
    Cornell University, Ithaca, New York
  Funding: Work supported by Cornell University.

The electron beam exiting an Energy Recovery Linac (ERL) is dumped close to the injection energy. This energy is chosen as low as possible while allowing the beam quality specifications to be met. As ERLs are designed for high average beam current, beam dumps are required to handle high beam power at low energy. Low energy electrons have a short range in practical dump materials, requiring the beam size at the dump face be enlarged to give acceptable power densities and heat fluxes. Cornell University is developing a 100 mA average current ERL as a synchrotron radiation source. The 13 MeV optimum injection energy requires a 1.3 MW beam dump. We present a mature design for this dump, using an array of water-cooled extruded copper tubes. This array is mounted in the accelerator vacuum normal to the beam. Fatigue failure resulting from abrupt thermal cycles associated with beam trips is a potential failure mechanism. We report on designs for a 75 kW, 750 keV tube-cooled beryllium plate dump for electron gun testing, and a 500 kW, 5 to 15 MeV copper tube dump for use with the prototype injector under development. We expect to test the beryllium dump within a year, and the higher power copper dump within 2-1/2 years.

WPAE044 An Alignment of J-PARC Linac alignment, linac, target, survey 2851
  • T. Morishita, H. Ao, T. Ito, A. Ueno
    JAERI/LINAC, Ibaraki-ken
  • K. Hasegawa
    JAERI, Ibaraki-ken
  • M. Ikegami, C. Kubota, F. Naito, E. Takasaki, H. Tanaka, K. Yoshino
    KEK, Ibaraki
  J-PARC linear accelerator components are now being installed in the accelerator tunnel, whose total length is more than 400 m including the beam transport line to RCS (Rapid Cycling Synchrotron). A precise alignment of accelerator components is essential for a high quality beam acceleration. In this paper, planned alignment schemes for the installation of linac components, the fine alignment before beam acceleration, and watching the long term motion of the building are described. Guide points are placed on the floor, which acts as a reference for the initial alignment at the installation and also as a relay point for the long surveying network linking at the fine alignment. For a straight line alignment, the wire position sensor is placed on the offset position with respect to the beam center by a target holder, then a single wire can cover the accelerator cavities and the focusing magnets at the DTL-SDTL section (120m). The hydrostatic levering system (HLS) is used for watching the floor elevation (changes) over the long period.  
WPAE063 CERN-PS Main Power Converter Renovation: How To Provide and Control the Large Flow of Energy for a Rapid Cycling Machine? acceleration, pulsed-power, superconductivity, superconducting-magnet 3612
  • F. Bordry, J.-P. Burnet, F. Voelker
    CERN, Geneva
  The PS (Proton-Synchrotron) at CERN, which is part of the LHC injector chain, is composed of 101 main magnets connected in series. During a cycle (about 1 second), the active power at the magnet terminals varies from plus to minus 40 MW. Forty years ago, the solution was to insert a motor-generator (M-G) set between the AC supply network and the load. The M-G set acts as a fly-wheel with a stored kinetic energy of 233 MJ. The power converter is composed of two 12-pulse rectifiers connected in series. A renovation or replacement of the installation is planned in the near future as part of the consolidation of the LHC injectors. This paper presents a first comparison of technical solutions: - a direct connection to the 400 kV mains; - a kinetic energy storage system either by the existing or by a new “state of the art” M-G set; - a new local inductive or capacitive energy storage system. All these solutions need new power electronics equipment, which should be based on proven industrial topologies, techniques and components. The related studies will address the challenge of controlling by a modern power converter with local energy storage the positive and negative flow of energy to a rapid cycling accelerator load.  
WPAE071 Power Supply for Magnet of Compact Proton and/or Heavy Ion Synchrotron for Radiotherapy power-supply, dipole, injection, acceleration 3859
  • S. Yamanaka
    NIRS, Chiba-shi
  • K. Egawa, K. Endo, Z. Fang
    KEK, Ibaraki
  A resonant type pulse power supply, for an application to a compact proton and/or heavy ion synchrotron with a several Hz repetition rate, is attractive from the view point of attaining an average beam current that is enough for the radiation therapy. Maximum ampere-turn of the dipole magnet is as large as 200 kAT to make the bending radius as small as possible. Pulse current is generated by discharging the stored energy in a capacitor bank through a pulse transformer. Moreover, the auxiliary power supply for the dipole magnets which adds the flat magnetic field (10-20μs) for the multi-turn beam-injection is being developed. The power supply for the quadrupole magnets is the high switching frequency (20 kHz × 5) switching-mode Power Supply for the adjusting tune and the tracking between the quadrupole and the dipole fields.Detailed analyses on these pulse power supplies will be presented.  
WPAE074 Trim Power Supplies for the Duke Booster and Storage Ring power-supply, storage-ring, feedback, booster 3919
  • V. Popov, S.M. Hartman, S. Mikhailov, O. Oakeley, P.W. Wallace, Y.K. Wu
    DU/FEL, Durham, North Carolina
  Funding: U.S. AFOSR MFEL grant F49620-001-0370 and HIGS Upgrade DOE grant number is DE-FG02-01ER41175.

The on-going Duke storage ring upgrades and the development of a new booster synchrotron injection require more than 100 units of high performance unipolar and bipolar trim power supplies in the current range of -15A to +15A. However, most of the trim power supplies on the market do not deliver two critical performance features simultaneously: a high current stability and a low current noise.An in-house trim power supply development program is then put in force to design, fabricate, and test low cost linear power supplies with current stability about 100 ppm and current ripples less than 100 ppm in a broad band. A set of unipolar power supplies (0-12A) have been designed, fabricated and successfully tested. Since August, 2004 they have been used in storage ring operation with excellent performance. The prototype of bipolar power supplies (± 15 A) has been designed and tested as well. The main design principles and their performance results of both unipolar and bipolar supplies will be presented in this paper.

WPAE075 Compact Digital High Voltage Charger impedance, feedback, power-supply, controls 3964
  • G. Li, Y.G. Zhou
    USTC/NSRL, Hefei, Anhui
  The operation of classical resonant circuit developed for the pulse energizing is investigated. The HV pulse or generator is very compact by a soft switching circuit made up of IGBT working at over 30 kHZ. The frequencies of macro pulses andμpulses can be arbitrarily tuned below resonant frequency to digitalize the HV pulse power. Theμpulses can also be connected by filter circuit to get the HVDC power. The circuit topology is given and its novel control logic is analyzed by flowchart. The circuit is part of a system consisting of a AC or DC LV power supply, a pulse transformer, the pulse generator implemented by LV capacitor and leakage inductance of the transformer, a HV DC or pulse power supply and the charged HV capacitor of the modulators.  
WPAT002 High Power (35 kW and 190 kW) 352 Solid State Amplifiers for the SOLEIL Synchrotron vacuum, power-supply, booster, insertion 811
  • P. Marchand, M.D. Diop, R.L. Lopes, J. Polian, F. Ribeiro, T. Ruan
    SOLEIL, Gif-sur-Yvette
  In the SOLEIL Storage Ring, two cryomodules, each containing a pair of superconducting cavities will provide the maximum power of 600 kW, required at the nominal energy of 2.75 GeV with the full beam current of 500 mA and all the insertion devices. Each of the four cavities will be powered with a 190 kW solid state amplifier consisting in a combination of 315 W elementary modules (about 750 modules per amplifier). The amplifier modules, based on a technology developed in house, with MOSFET transistor, integrated circulator and individual power supply, are fabricated in the industry. In the booster, a 35 kW solid state amplifier (147 modules) will power a 5-cell copper cavity of the LEP type. The first operational results and the status of the RF power plants are reported in this paper. Although quite innovative for the required power range, the solid state technology proved to be very attractive with significant advantages as compared to vacuum tubes.  
WPAT007 Control Loops for the J-PARC RCS Digital Low-Level RF Control acceleration, feedback, controls, damping 1063
  • A. Schnase, M. Nomura, F. Tamura, M. Yamamoto
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Yoshii
    KEK, Ibaraki
  The low-level radiofrequency control for the Rapic Cycling Syncrotron of J-PARC is based on digital signal processing. This system controls the acceleration voltages of 12 magnetic alloy loaded cavities. To achive a short overall delay, mandatory for stable loop operation, the data-processing is based on distributed arithmetics in FPGA. Due to the broadband characteristic of the acceleration cavities, no tuning loop is needed. To handle the large beam current, the RF system operates simultaneously with dual harmonics (h=2) and (h=4). The stability of the amplitude loops is limited by the delay of the FIR filters used after downconversion. The phase loop offers several operation modes to define the phase relation of (h=2) and (h=4) between the longitudinal beam signal and the vector-sum of the cavity voltages. Besides the FIR filters, we provide cascaded CIC filters with smoothly varying coefficients. Such a filter tracks the revolution frequency and has a substantially shorter delay, thereby increasing the stable operating region of the phase loops. The adaptive radial loop accumulates the orbit variation over several machine cycles to reduce the effects of measurement errors on the effective acceleration frequency program.  
WPAT009 Status of the RF System for the 6.5 GeV Synchrotron Light Source PF-AR vacuum, coupling, synchrotron-radiation, radiation 1168
  • S. Sakanaka, K. Ebihara, S. Isagawa, M. Izawa, T. Kageyama, T. Kasuga, H. Nakanishi, M. Ono, H. Sakai, T. Takahashi, K. Umemori, S.I. Yoshimoto
    KEK, Ibaraki
  The Photon Factory Advanced Ring (PF-AR) is a 6.5-GeV synchrotron light source at KEK. An rf system comprises two 1.2-MW klystrons, six alternating-periodic-structure (APS) cavities, and other components. It supplies an rf voltage of about 15 MV with a beam current of 60 mA. The system has been working well, except for a trouble (frequent trips with beams) in one of the cavities. We found that the trips were triggered by an irradiation of synchrotron radiation to the cavity wall. In the summer of 2004, we reorganized the rf system, which allows us to install two insertion devices in a part of the rf sections. We replaced the troubled cavity at a time. We report both the operation status and the modification of the rf system.  
WPAT016 Stable Low Noise RF Source for Main Ring storage-ring, feedback, electron, scattering 1494
  • G.Y. Kurkin
    BINP SB RAS, Novosibirsk
  • P. Wang
    DU/FEL, Durham, North Carolina
  The Duke Storage ring is a 1 Gev electron ring, which is designed for driving UV-VUV FEL. It also provides variable energy high intensive gamma rays by Compton back scattering. It requires an RF master oscillator with very low phase noise. We built a Surface Acoustic Wave (SAW) Oscillator. However, the long-term stability does not meet requirements for FEL ring. Previously we used a commercial signal generator HP 4400B as the master oscillator. It has excellent long-term stability, but the phase noise is not acceptable. A phase feedback loop has been added between the SAW oscillator and the HP source, which provides us an excellent RF source. The design details and the test results are presented in this paper.  
WPAT024 First Results from the Use of Dual Harmonic Acceleration on the ISIS Synchrotron acceleration, proton, beam-losses, injection 1871
  • A. Seville, D. Bayley, R.G. Bendall, M.G. Glover, A. Morris, J.W.G. Thomason
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  • D.J. Adams, I.S.K. Gardner, C.M. Warsop
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  The ISIS facility at the Rutherford Appleton Laboratory in the UK is currently the most intense pulsed, spallation, neutron source. The accelerator consists of a 70 MeV H- Linac and an 800 MeV, 50 Hz, rapid cycling, proton Synchrotron. The synchrotron beam intensity is 2.5x1013 protons per pulse, corresponding to a mean current of 200 μA. The synchrotron beam is accelerated using six, ferrite loaded, RF cavities with harmonic number 2. Four additional, harmonic number 4, cavities have been installed to increase the beam bunching factor with the potential of raising the operating current to 300 μA. This paper reports on the hardware commissioning and the first beam tests.  
WPAT025 First Results of the IOT Based 300 kW 500 MHz Amplifier for the Diamond Light Source factory, power-supply, radio-frequency, background 1883
  • M. Jensen, M. Maddock, S. Rains, A.V. Watkins
    Diamond, Oxfordshire
  • J. Alex, M. Mueller
    Thales Broadcast & Multimedia AG, Turgi
  We present the first RF measurements of the IOT based 300 kW 500 MHz amplifier for the Diamond Light Source. Four 80 kW IOTs are combined using a waveguide combiner to achieve the RF requirement of up to 300 kW for each of three superconducting cavities for the main storage ring. The IOTs are protected by a full power circulator and a 300 kW ferrite RF load. This is the first time IOTs will be used for a synchrotron light source. This paper gives an overview of the design of the Thales amplifiers and IOTs with commissioning results including measurements of key components and overall RF performance following factory tests and the installation of the first unit  
WPAT039 Experience with the New Digital RF Control System at the CESR Storage Ring klystron, feedback, storage-ring, vacuum 2592
  • M. Liepe, S.A. Belomestnykh, J. Dobbins, R.P.K. Kaplan, C.R. Strohman, B.K. Stuhl
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: This work is supported by NSF.

A new digital control system has been developed, providing great flexibility, high computational power and low latency for a wide range of control and data acquisition applications. This system is now installed in the CESR storage ring and stabilizes the vector sum field of two of the superconducting CESR 500 MHz cavities and the output power from the driving klystron. The installed control system includes in-house developed digital and RF hardware, very fast feedback and feedforward control, a state machine for automatic start-up and trip recovery, cw and pulsed mode operation, fast quench detection, and cavity frequency control. Several months of continuous operation have proven high reliability of the system. The achieved field stability surpasses requirements.

WPAT052 Present Status of RF System for Medical Proton Synchrotron proton, acceleration, feedback, impedance 3185
  • Z. Fang, K. Egawa, K. Endo, S. Yamanaka
    KEK, Ibaraki
  • Y. Cho, T. Fusato, T. Hirashima
    DKK, Kanagawa
  The 200MeV proton synchrotron of circumference of 9.54m is being developed for medical radiotherapy. The rf system has been carried out with a wide bandwidth of frequency sweeping from 2.0MHz to 17.8MHz. The rf cavity is designed of a compact dimension and a high acceleration gradient. The high power test of the rf system has been successfully performed and maximal acceleration gradient of 60kV/m has been achieved. The experiments with feedback control system are being studied by using a dummy beam signal. In this paper, the recent progress of the rf system and test results will be presented in detail.  
WPAT064 Low Level RF Control System of J-PARC Synchrotrons beam-loading, proton, feedback, linac 3624
  • F. Tamura
    JAERI/LINAC, Ibaraki-ken
  • S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Yoshii
    KEK, Ibaraki
  • M. Nomura, A. Schnase, M. Yamamoto
    JAERI, Ibaraki-ken
  We present the concept and the design of the low level RF (LLRF) control system of the J-PARC synchrotrons. The J-PARC synchrotrons are the rapid cycling 3-GeV synchrotron (RCS) and the 50-GeV main ring (MR) which require very precise and stable LLRF control systems to accelerate the ultra-high proton beam current. The LLRF system of the synchrotron is a full-digital system based on the direct digital synthesis (DDS). The functions of the system are (1) the multi-harmonic RF generation for the acceleration and the longitudinal bunch shaping, (2) the feedbacks for stabilizing the beam, (3) the feedforward for compensating the heavy beam loading, and (4) other miscellaneous functions such as the synchronization and chopper timing. The LLRF system of the RCS is now under construction. We present the details of the system. Also, we show preliminary results of performance tests of the control modules.  
WPAT066 ALS Booster Ring RF System Upgrade for Top-Off Mode of Operation booster, linac, storage-ring, injection 3709
  • S. Kwiatkowski, K.M. Baptiste
    LBNL, Berkeley, California
  Funding: Supported by the U.S. Department of Energy under Contract No.DE-AC03-76SF00098.

ALS is one of the first third generation synchrotron light sources which has been operating since 1993 at Berkeley Lab. In the present ALS operation scenario 1.5GeV electron beam is injected from the booster into the storage ring every 8 hours where is accelerated to the final energy of 1.9GeV. The beam decays between fills from 400mA to 200mA with the time average current of 250mA. In order to increase the beam brighthess ALS team plans to increase the beam current to 500mA and maintain it constant during machine operation ("Top-Off" mode of operation). This operation scenario will require full energy injection from the booster ring into the storage ring and constant operation of the injector (10 bunches with the total charge of 1nC every 30 to 35 seconds). In this paper we will present the results of the ALS injector RF system analysis fo Top-Off mode of operation and describe the way we intent to implement the necessary modifications to the booster RF system.

WPAT068 Development of Low Level RF Control Systems for Superconducting Heavy Ion Linear Accelerators, Electron Synchrotrons and Storage Rings rfq, electron, booster, storage-ring
  • B. A. Aminov, A. Borisov, S. K. Kolesov, H. Piel
    CRE, Wuppertal
  • M. Pekeler, C. Piel
    ACCEL, Bergisch Gladbach
  Since 2001 ACCEL Instruments is supplying low level RF control systems together with turn key cavity systems. The early LLRF systems used the well established technology based on discrete analogue amplitude and phase detectors and modulators. Today analogue LLRF systems can make use of advanced vector demodulators and modulators combined with a fast computer controlled analogue feed back loop. Feed forward control is implemented to operate the RF cavity in an open loop mode or to compensate for predictable perturbations. The paper will introduce the general design philosophy and show how it can be adapted to different tasks as controlling a synchrotron booster nc RF system at 500 MHz, or superconducting storage ring RF cavities, as well as a linear accelerator at 176 MHz formed by a chain of individually driven and controlled superconducting λ/2 cavities.  
WPAT072 A 1.3GHz Inductive Output Tube for Particle Accelerators electron, gun, cathode, target 3883
  • E. Sobieradzki, A.E. Wheelhouse
    e2v technologies, Chelmsford, Essex
  There is an increasing requirement for RF power sources in the L-band frequency range for operation in particle accelerators. The paper describes the development and presents test results of a new inductive output tube (IOT) for use at 1.3GHz. A target specificationof 16kW cw output power at an efficiency of 60% was set. The paper discusses progress to date having used an electron gun geometry that minimizes transit time effects in the cathode to grid gap.  
WPAT076 Resonant High Power Combiners insertion, resonance, impedance, radio-frequency 3970
  • M.L. Langlois, J.P. Buge, G. Peillex-Delphe
    TED, Vélizy Cedex
  Particle accelerators need radio frequency sources. Above 300 MHz, the amplifiers mostly used high power klystrons developed for this sole purpose. As for military equipment, users are drawn to buy "off the shelf" components rather than dedicated devices. IOTs have replaced most klystrons in TV transmitters and find their way in particle accelerators. They are less bulky, easier to replace, more efficient at reduced power. They are also far less powerful. What is the benefit of very compact sources if huge 3 dB couplers are needed to combine the power? To alleviate this drawback, we investigated a resonant combiner, operating in TM010 mode, able to combine 3 to 5 IOTs. Our IOTs being able to deliver 80 kW C.W. apiece, combined power would reach 400 kW minus the minor insertion loss. Values for matching and insertion loss are given. The behavior of the system in case of IOT failure is analyzed.  
WPAT079 Design of a Direct Converter for High Power, RF Applications feedback, booster, target, radio-frequency 4033
  • D. Cook, M. Catucci, J. Clare, P. W. Wheeler
    University of Nottingham, Nottingham
  • J.S. Przybyla
    EEV, Chelmsford, Essex
  Funding: Particle Physics and Astronomy Research Council.

This paper is concerned with a new type of power supply for high power RF applications for CW operation. The converter is a direct topology operating with a high frequency (resonant) link. Switching losses are minimised by switching at zero current. High operating frequency allows for minimised transformer and filter size. Advantages of this topology over conventional approaches are discussed, along with the potential problems and proposed solutions. Recently, considerable interest has been shown in direct converter topologies as an alternative topology in motor drive applications. This approach offers advantages such as reduced energy storage and higher energy density compared to conventional topologies. The work presented in this paper capitalises on these advantages in other fields, namely power conversion for RF supplies. The RF power needs to be stable and predictable such that any variation has a limited impact on the accelerated beam quality. In order to meet the required output voltage specification such designs require output filters with consequent energy storage. Management of this energy in the event of a fault is necessary if destruction of the tube is to be avoided.

WOAB001 The Australian Synchrotron Project - Update storage-ring, injection, site, vacuum 102
  • A. Jackson
    ASP, Clayton, Victoria
  The Australian Synchrotron – a synchrotron light facility based on a 3-GeV electron storage ring – is under construction at a site in the Metropolitan District of Melbourne. Building preparation started on a “green-field” site in September 2003 and staff moved in to their new offices in February 2005. Installation of the technical equipment started in April 2005 with all accelerator contracts expected to be completed before April 2006. Storage Ring commissioning with beam will start in June 2006, and project completion is scheduled for March 2007. In this paper we present an overview of the facility and discuss progress to date in meeting this very aggressive schedule.  
WOAB002 Status of the Shanghai Synchrotron Radiation Facility storage-ring, booster, linac, injection 214
  • Z. Zhao, H. Ding, H. Xu
    SINAP, Shanghai
  The Shanghai Synchrotron Radiation Facility (SSRF) made its ground breaking at Zhang-Jiang High Tech Park on Dec.25, 2004 and moved into its construction phase with the plan of commencing user’s operation from April 2009. The SSRF complex is based on a 3.5GeV storage ring optimized to operate with top-up injection, mini-gap undulators and superconducting RF system, the 432m circumference storage ring provides 18 ID straight sections (4X12.0m and 16X6.5m), and four of them will be used for the first SSRF beam lines. The SSRF project was proposed in 1995, and since then it has experienced the conceptual design stage, the R&D program and the design optimization phase. This paper presents the updated design specifications and the construction status of the SSRF project.  
WOAB003 The Brazilian Synchrotron Light Source storage-ring, injection, booster, insertion 325
  • P.F. Tavares, J.A. Brum
    LNLS, Campinas
  The Brazilian Synchrotron Radiation Laboratory has been operating the only light source in the southern hemisphere since July 1997. Over this 7 year period, approximately 22000 hours of beam time were delivered to users from all over Brazil as well as from 10 other countries. In this article, we report on the present configuration of the 1.37 GeV electron storage ring and associated instrumentation, describe recent improvements to the light source and analyze future prespectives including the installation of insertion devices and additional beamlines.  
WOAB004 Applying Frequency Map Analysis to the Australian Synchrotron Storage Ring sextupole, resonance, quadrupole, dynamic-aperture 407
  • Y.E. Tan, M.J. Boland, G. LeBlanc
    ASP, Clayton, Victoria
  The technique of frequency map analysis has been applied to study the transverse dynamic aperture of the Australian Synchrotron Storage Ring. The results have been used to set the strengths of sextupoles to optimise the dynamic aperture. The effects of the allowed harmonics in the quadrupoles and dipole edge effects are discussed.  
WOAB007 SESAME in Jordan dipole, sextupole, vacuum, injection 586
  • G. Vignola, A. Amro, M. Attal, F. Makahleh, M.M. Shehab, S. Varnasseri
    SESAME, Amman
  An overview of the status of SESAME is presented. SESAME (Synchrotron-light for Experimental Science and Application in the Middle East) is an Independent Intergovernmental Organization developed and officially established under the auspices of UNESCO. It involves at the present the following Member States: Bahrain, Egypt, Islamic Republic of Iran, Israel, Jordan, Pakistan, Palestinian Authority, Turkey and United Arab Emirates. Moreover the following States are Observer of SESAME Council: France, Germany, Greece, Italy, Kuwait, Russian Federation, Sweden, UK and United States of America. SESAME will become a major international research center in the Middle East, located in Allan, Jordan. The machine design is based on a 2.5 GeV 3rd generation Light Source with an emittance of 26 nm.rad and 11 straights for insertion devices. The conceptual design of the accelerator complex has been frozen and the engineering design is started. The Phase I scientific program for SESAME has also been finalized and it foresees 6 beamlines. The construction of SESAME building is in progress and the beneficial occupancy is expected by the first half of 2006. The completion of the accelerators complex construction is scheduled for the end of 2009.  
WOAB009 Design, Development, Construction and Installation of a Ceramic Chamber for a Pulsed Kicker at the LNLS Storage Ring vacuum, kicker, booster, storage-ring 689
  • M.J. Ferreira, O.R. Bagnato, R.O. Ferraz, F. R. Francisco, A. L. Gobbi, R.M. Seraphim, M.B. Silva
    LNLS, Campinas
  Funding: MCT - ABTLuS/LNLS.

Following the upgrade of the LNLS injector system with the addition of a 500 MeV booster synchrotron,the storage ring in-vacuum ferrite injection kicker magnets started to show overheating due the interaction with high frequency electromagnetic fields induced by the electron beam. In this paper, we describe the design of a new ceramic chamber for the kickers which minimize this effect by decreasing the coupling impedance of the kickers and their interaction with the electron beam.

WOAC005 Application of Independent Component Analysis for Beam Diagnosis betatron, booster, lattice, injection 489
  • X. Huang, S.-Y. Lee
    IUCF, Bloomington, Indiana
  • E. Prebys, R.E. Tomlin
    Fermilab, Batavia, Illinois
  Funding: This work is supported in part by grants from DE-AC02-76CH03000, DOE DE-FG02-92ER40747 and NSF PHY-0244793.

The independent component analysis (ICA)* is applied to analyze simultaneous multiple turn-by-turn beam position monitor (BPM) data of synchrotrons. The sampled data are decomposed to physically independent source signals, such as betatron motion, synchrotron motion and other perturbation sources. The decomposition is based on simultaneous diagonalization of several unequal time covariance matrices, unlike the model independent analysis (MIA),** which uses equal-time covariance matrix only. Consequently the new method has advantage over MIA in isolating the independent modes and is more robust under the influence of contaminating signals of bad BPMs. The spatial pattern and temporal pattern of each resulting component (mode) can be used to identify and analyze the associated physical cause. Beam optics can be studied on the basis of the betatron modes. The method has been successfully applied to the Booster Synchrotron at Fermilab.

*A. Belouchrani et al., IEEE Trans. on Signal Processing, {\bf 45}, 434-444, (1997). **J. Irwin, et al., Phys. Rev. Lett. {\bf 82}, 1684 (1999); Chun-xi Wang, et al., Phys. Rev. ST Accel. Beams} {\bf 6}, 104001 (2003).

WOAC008 Measuring and Understanding the Momentum Aperture in a Storage Ring resonance, coupling, scattering, storage-ring 645
  • C. Steier, D. Robin
    LBNL, Berkeley, California
  • W. Decking
    DESY, Hamburg
  • J. Laskar
    IMCCE, Paris
  • L.S.N. Nadolski
    SOLEIL, Gif-sur-Yvette
  • Y.K. Wu
    DU/FEL, Durham, North Carolina
  Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098.

The momentum aperture of a storage ring is a very important parameter that strongly influences the performance, especially the beam lifetime. For the special case of synchrotron light sources with small emittance like the Advanced Light Source (ALS), the momentum aperture depends strongly on the transverse dynamics. It is very sensitive to machine conditions such as the tunes, chromaticities, lattice symmetry, and spurious coupling, since depending on those conditions the Touschek scattered particles explore different resonance regions in the phase space. In light sources, the momentum aperture usually also depends strongly on the vertical physical aperture. Applying frequency analysis techniques in simulations and for turn-by-turn orbit measurement data provides a very powerful tool to measure and understand limitations of the dynamic momentum aperture. The techniques presented are applicable to other light sources, as well as damping rings and many types of colliders.

WOAC010 Measurement of Linear Lattice Functions in the ESRF Storage Ring Using Turn-by-Turn Data optics, storage-ring, kicker, damping 698
  • Y. Papaphilippou, L. Farvacque, J.-L. Revol, V. Serriere
    ESRF, Grenoble
  • S.-L. Bailey
    The College of William and Mary, Williamsburg
  A model-independent method to measure linear optics functions has been tested in turn-by-turn data from the ESRF storage ring. This method does not necessitate neither the knowledge of the model nor magnetic element manipulation. It uses only the positions measured in consecutive BPMs of betatron oscillations issued by small transverse kicks. The phase advances and tunes necessary to construct the transfer matrices are issued by refined Fourier analysis. The method's precision is compared with classical methods such as response matrix analysis and beam matrix construction.  
ROAA003 Proposal of an Experiment on Bunch Length Modulation in DAFNE dynamic-aperture, storage-ring, luminosity, factory 336
  • C. Biscari, D. Alesini, G. Benedetti, M.E. Biagini, R. Boni, M. Boscolo, A. Clozza, G.O. Delle Monache, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, C. Vaccarezza, M. Vescovi, M. Zobov
    INFN/LNF, Frascati (Roma)
  • J.M. Byrd, F. Sannibale
    LBNL, Berkeley, California
  • J.D. Fox, D. Teytelman
    SLAC, Menlo Park, California
  • E. Levichev, P.A. Piminov, D.N. Shatilov
    BINP SB RAS, Novosibirsk
  • C. Pagani
    INFN/LASA, Segrate (MI)
  Obtaining very short bunches is a challenge for colliders and Coherent Synchrotron Radiation sources as well. The modulation of the bunch length in a strong RF focusing regime has been proposed, corresponding to a large value of the synchrotron tune. A ring structure where the dependence of the longitudinal position of a particle on its energy (R56) along the ring oscillates between large positive and negative values can produce a bunch length modulation. The synchrotron frequency can be tuned both by means of the rf voltage and by the integral of R56, down to the limit of zero value corresponding to the isochronicity condition. We present here the proposal of bunch length modulation along the DAFNE rings. Its lattice can be tuned to positive or negative momentum compaction, or to structures in which the two arcs are alternately set to positive/negative integrals of R56. With the proposed installation of an extra RF system at 1.3 GHz, experiments on bunch length modulation both in the high and low synchrotron tune regimes can be realized.  
ROAA004 MICE: The International Muon Ionisation Cooling Experiment emittance, instrumentation, coupling, optics 398
  • P. Drumm
    CCLRC/RAL, Chilton, Didcot, Oxon
  Muon storage rings have been proposed for use as sources of intense high-energy neutrino beams and as the basis for multi-TeV lepton-antilepton colliding beam facilities. To optimise the performance of such facilities is likely to require the phase-space compression (cooling) of the muon beam prior to acceleration and storage. The short muon-lifetime makes it impossible to employ traditional techniques to cool the beam while maintaining the muon-beam intensity. Ionisation cooling, a process in which the muon beam is passed through a series of liquid hydrogen absorbers followed by accelerating RF-cavities, is the technique proposed to cool the muon beam. The international Muon Ionisation Cooling Experiment (MICE) collaboration has been formed to carry out a muon-cooling demonstration experiment, and its proposal to Rutherford Appleton Laboratory has been approved. The MICE cooling channel, the instrumentation and the implementation at the Rutherford Appleton Laboratory is described together with the predicted performance of the channel and the measurements that will be made.  
ROAC005 Present Status of J-PARC Ring RF Systems extraction, injection, power-supply, feedback 475
  • M. Yoshii, S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Toda
    KEK, Ibaraki
  • M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
    JAERI, Ibaraki-ken
  The accelerator of the J-PARC complex consists of the 400 MeV (initially 181 MeV) linac, the rapid cycling 3 GeV Synchrotron and the 50 GeV main Synchrotron. To accelerate an ultra-high intense proton beam, the synchrotrons require a high field gradient rf system (~25kV/m). Alleviating space charge effects is a key issue for minimizing beam losses during a cycle. Longitudinal bunch manipulation is also considered as well as acceleration. Magnetic alloy loaded cavities are the most practical choice for the J-PARC. Such system provides high field gradient, and broadband behavior. It is a stable passive system without tuning control. Multi-tone signals can be fed into the same cavity for acceleration and bunch manipulation. However, the harmonics of circulating beam current within the cavity bandwidth must be taken into account. A feed-forward scheme is used for compensating the beam induced voltages. The low level rf system is fully digital to provide precise control. The specification is based on high reliability and reproductivity. The design consideration of the whole rf system will be described and the current status presented.  
RPAE036 Damping Wigglers for the PETRA III Light Source wiggler, damping, emittance, radiation 2446
  • M. Tischer, K. Balewski, W. Decking, M. Seidel, L. Yongjun
    DESY, Hamburg
  • V. Kuzminykh, E. Levichev, P. Vobly, K. Zolotariov
    BINP SB RAS, Novosibirsk
  Within the reconstruction of the PETRA booster ring at DESY towards a third generation light source after 2007, damping wigglers will be installed to reduce the emittance to a value of 1 nmrad. Two damping sections in the long straights of PETRA have been assigned to accommodate 20 wigglers in total. The wigglers will be permanent magnet devices with a fixed gap which are surrounded by an iron enclosure to reduce the leakage flux. Each wiggler will provide a damping integral of 4 T2m per segment and generate a synchrotron radiation power of 42 kW. A short one period long prototype has recently been built to prove the magnetic design and study the correction scheme for tuning the pole strength. The wiggler segments will be followed by an SR absorber shading the downstream quadrupole and successive wiggler segment, the accumulated on-axis power of about 200 kW will be taken up by the final absorber at the damping section end.  
RPAE038 Far Infrared Coherent Synchrotron Edge Radiation at ANKA radiation, storage-ring, synchrotron-radiation, optics 2518
  • A.-S. Müller, I. Birkel, B. Gasharova, E. Huttel, R. Kubat, Y.-L. Mathis, W. Mexner, D.A. Moss, F. Pérez, R. Rossmanith, P. Wesolowski, M. Wuensch
    FZK, Karlsruhe
  • C. J. Hirschmugl
    UWM, Milwaukee, Wisconsin
  • M. Pont
    CELLS, Bellaterra (Cerdanyola del Vallès)
  A synchrotron radiation source emits coherent infrared (IR) radiation when the electron bunch length is comparable to the wavelength of the emitted radiation. To generate coherent radiation in the far IR (THz) region, a "low alpha mode" has been devised at the ANKA storage ring operating at 1.3 GeV. The corresponding lattice has a significantly reduced momentum compaction factor. The spectral dependence of the emitted radiation is recorded at the ANKA-IR beamline, where the synchrotron light is produced in the fringe field of a bending magnet. This edge radiation has the advantage of being more collimated than constant field radiation. This allows the observation of frequencies down to 1 cm-1 through a modest vertical aperture, which would not be possible with classical constant field emission due to the increasing beam divergence with decreasing frequency. The onset of coherent emission is found at a synchrotron frequency of about 10 kHz. At 5 kHz, an intensity enhancement of up to 5 orders of magnitude, with respect to the incoherent emission, is observed in the spectral range between 1 and 65 cm-1.  
RPAE039 Operation of the ANKA Synchrotron Light Source with Superconductive Undulators undulator, synchrotron-radiation, radiation, vacuum 2559
  • R. Rossmanith, MH. Hagelstein, B.K. Kostka, A.-S. Müller, D. Wollmann
    FZK, Karlsruhe
  • T. Baumbach, A. Bernhard
    FZ Karlsruhe, Karlsruhe
  • E. Steffens
    Erlangen University, Erlangen
  • M. Weisser
    University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
  The synchrotron light source ANKA (2.5 GeV, 200 mA) is a versatile multi-purpose storage ring with beam lines for coherent IR and THz radiation (IR-laser), LIGA applications and high brilliance X-rays. It is now plannned to install in addition several superconductive undulators for a wide range of applications: fast tunable X-rays for material research, imaging applications and an undulator with variable polarization direction for a dichroism beamline. This development of ANKA is the result of successful research on superconductive undulators which surpass the performance of permanent undulators by far (collaboration between ANKA, the University of Karlsruhe and the University of Erlangen-Nürnberg). The basic layout of the undulators and the required changes to a storage ring to accommodate the superconductive undulators is described in this paper.  
RPAE045 Production of Short Electron Bunches by Slow and Fast Excitations of Longitudinal Bunch-Shape Oscillations simulation, radiation, storage-ring, damping 2887
  • S. Sakanaka, T. Mitsuhashi, T. Obina, K. Umemori
    KEK, Ibaraki
  In the Brookhaven Alternating Gradient Synchrotron (AGS), adiabatic excitation of longitudinal bunch-shape oscillations has been successfully used for extracting shortened proton bunches.* We applied this technique to the electron storage ring. In case of electron machines, growth time of bunch-shape oscillations should be shorter than the radiation damping time for preventing radiation excitation. We demonstrated in the 2.5-GeV Photon Factory storage ring that electron bunches could be shortened by a factor of about two from its natural length using this technique. We show that non-adiabatic excitation of oscillations is also very useful for obtaining shorter bunches.

*M. Bai et al., Phys. Rev. ST Accel. Beams 3, 064001 (2000).

RPAE048 Design Consideration of a Booster for Taiwan Photon Source booster, emittance, lattice, storage-ring 2992
  • G.-H. Luo, H.-P. Chang, C.-C. Kuo, K.-K. Lin, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
  After more than 10 years' operation and expansion, the Taiwan Light Source (TLS) of National Synchrotron Radiation Research Center (NSRRC) reaches very stable operation condition. The storage ring has better than 96% of beam availability annually with 6 Insertion Devices (ID) in a six-folds symmetry over-crowded machine. Two superconducting IDs and one superconducting RF cavity were installed in recent year, which intend to push the photon energy to hard x-ray regime and double the photon flux with better beam quality. Beamlines and experimental stations occupied all over the experimental area. The uproar for more beamlines in higher photon energy with higher brightness was frequently transpired from users' community. The Board of Trustee of NSRRC gave a green light to a new design and construction of median-energy light source, Taiwan Photon Source (TPS) in the coming decade. This paper will present two draft designs of booster and the consideration of the design criteria for new booster to work with a top-up injected and very low-emittance storage ring.  
RPAE053 Transient Generation of Short Pulses in the APS Storage Ring simulation, storage-ring, single-bunch, photon 3247
  • G. Decker, N. Sereno
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

A method for obtaining very short pulses using modulation of the accelerating voltage gradient is described and simulation results given. The idea is to operate the two rf stations with a phase separation adjusted so that the synchronous particle resides on the crest of one of the sources. Phase modulation of the on-crest system at twice the synchrotron frequency induces a longitudinal bunch shape oscillation with significantly reduced bunch length occurring twice each synchrotron period. Pulsed and steady-state operation will be discussed using various accelerator parameters.

RPAE055 Results of Preliminary Tests of PAR Bunch Cleaning booster, injection, storage-ring, linac 3307
  • C. Yao, M. Borland, A. Grelick, A.H. Lumpkin, N. Sereno
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

A particle accumulator ring (PAR) is used at the Advanced Photon Source (APS) to collect multiple linac bunches and compress them into a 0.3-ns (rms) single bunch for booster injection. A 9.77-MHz fundamental rf system and a 117.3-MHz harmonic rf system are employed for initial beam capture and bunch length compression. Satellite bunches with very low charge form due to rf phase drifts or beam loading change. These satellites, when injected into the booster and then into the storage ring (SR), cause bunch impurity at three buckets from the target bucket. Storage ring and booster bunch cleaning was tried but proved to be difficult due to the top-up mode of operation in the storage ring and tune drift in the booster synchrotron. Recently we implemented a PAR bunch-cleaning system with tune-modulated harmonic rf knockout. Preliminary tests gave a measured SR bunch purity of better than 10-6, which shows that the cleaning method is feasible and could achieve a bunch purity goal of 10-8. This report describes the system configuration, test results, and system performance.

RPAE056 NSLS II: The Future of the NSLS brightness, insertion, insertion-device, photon 3345
  • J.B. Murphy, J. Bengtsson, R. Biscardi, A. Blednykh, G.L. Carr, W.R. Casey, S. Chouhan, S.B. Dierker, E. Haas, R. Heese, S. Hulbert, E.D. Johnson, C.C. Kao, S.L. Kramer, S. Krinsky, I.P. Pinayev, S. Pjerov, B. Podobedov, G. Rakowsky, J. Rose, T.V. Shaftan, B. Sheehy, J. Skaritka, N.A. Towne, J.-M. Wang, X.J. Wang, L.-H. Yu
    BNL, Upton, Long Island, New York
  Funding: Under Contract with the United States Department of Energy Contract Number DE-AC02-98CH10886

The National Synchrotron Light Source at BNL was the first dedicated light source facility and it has now operated for more than 20 years. During this time the user community has grown to more than 2400 users annually. To insure that this vibrant user community has access to the highest quality photon beams, the NSLS is pursuing the design of a new ultra-high brightness (~10E21) electron storage ring, tailored to the 0.3-20 KeV photon energy range. We present our preliminary design and review the critical accelerator physics design issues.

RPAE060 Simulation and Automation of the EEBI Test at ALS target, simulation, vacuum, monitoring 3485
  • H. Nishimura, W.E. Byrne
    LBNL, Berkeley, California
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

The Errant Electron Beam Interlock (EEBI) is a system that protects the vacuum chamber of the Advanced Light Source (ALS) from synchrotron light damage should the orbit, through a superconducting bend magnet (superbend), become distorted. The EEBI system monitors the vertical beam position on two BPMs, one upstream and the other downstream, of the superbend and dumps the stored beam if the orbit exceeds preset limits in either offset or angle. Discussed are the modeling studies carried out to determine how to create a large vertical bump, both for performing the test and implementing the automated test software.

RPAE065 Generation of Picosecond X-Ray Pulses in the ALS Using RF Orbit Deflection electron, radiation, photon, storage-ring 3659
  • D. Robin, J.M. Byrd, P. Fischer, P.A. Heimann, D.H. Kim, S. Kwiatkowski, D. Li, F. Sannibale, C. Steier, W. Wan, W. Wittmer, A. Zholents
    LBNL, Berkeley, California
  Funding: This work was supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098.

A scheme is studied for producing ps length pulses of x-ray radiation from the Advanced Light Source (ALS) using two RF deflecting cavities. The cavities create vertical displacements of electrons correlated with their longitudinal position in the bunch. The two cavities separated by 180 degrees of vertical phase advance. This allows the vertical kick from one cavity to be compensated by the vertical kick of the other. The location of the cavities corresponds to the end of one straight section and the beginning of the following straight section. Halfway between the cavities a bending magnet source is located. The radiation from the bend can be compressed to ~1 ps in duration.

RPAE066 Terahertz Coherent Synchrotron Radiation from Femtosecond Laser Modulation of the Electron Beam at the Advanced Light Source laser, radiation, lattice, electron 3682
  • J.M. Byrd, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, A. Zholents, M.S. Zolotorev
    LBNL, Berkeley, California
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

At the Advanced Light Source (ALS), the "femtoslicing" beamline is in operation since 1999 for the production of x-ray synchrotron radiation pulses with femtosecond duration. The mechanism used for generating the short x-ray pulses induces at the same time temporary structures in the electron bunch longitudinal distribution with very short characteristic length. Such structures emit intense coherent synchrotron radiation (CSR) in the terahertz frequency range. This CSR, whose measured intensity is routinely used as a diagnostics for the tune-up of the femtoslicing experiments, represents a potential source of terahertz radiation with very interesting features. Several measurements have been performed for its characterization and in this paper an updated description of the experimental results and of their interpretation is presented.

RPAE068 Very Short Bunches in MIT-Bates South Hall Ring optics, lattice, electron, radiation 3768
  • D. Wang, dc. Cheever, M. Farkhondeh, W.A. Franklin, W. Graves, E. Ihloff, C. Tschalaer, D. Wang, D. Wang, F. Wang, T. Zwart, J. van der Laan
    MIT, Middleton, Massachusetts
  • B. Podobedov
    BNL, Upton, Long Island, New York
  Funding: Department of Energy

The study of ultra-short bunches in MIT SHR storage ring with very small momentum compactions is carried out. The ultra-short bunches are to greatly enhence the coherent radiation by many orders of magnitude. The ring lattice is resigned to reach very small momentum compaction factor down to 1·10-5 levels. The measurement is performed with the streak camera. The various associated issues are discussed.

RPAE069 Terahertz Coherent Synchrotron Radiation in the MIT-Bates South Hall Ring lattice, storage-ring, electron, laser 3783
  • F. Wang, dc. Cheever, M. Farkhondeh, W.A. Franklin, W. Graves, E. Ihloff, C. Tschalaer, D. Wang, D. Wang, T. Zwart, J. van der Laan
    MIT, Middleton, Massachusetts
  • G.L. Carr, B. Podobedov
    BNL, Upton, Long Island, New York
  • F. Sannibale
    LBNL, Berkeley, California
  We investigate the terahertz coherent synchrotron radiation (CSR) potential of the South Hall Ring (SHR) at MIT-Bates Linear Accelerator Center. The SHR is equipped with a unique single cavity, 2.856 GHz RF system. The high RF frequency is advantageous for producing short bunch length and for having higher bunch current threshold to generate stable CSR. Combining with other techniques such as external pulse stacking cavity, femtosecond laser slicing, the potential for generating ultra-stable, high power, broadband terahertz CSR is very attractive. Beam dynamics issues related to short bunch length operation, and may associated with the high frequency RF system, such as multi-bunch instability are concerned. They could affect bunch length, bunch intensity and beam stability. The SHR is ideal for experimental exploration of these problems. Results of initial test of low momentum compaction lattice and bunch length measurements are presented and compared to expectations.  
RPAE072 Simulations of X-Ray Slicing and Compression Using Crab Cavities in the Advanced Photon Source sextupole, emittance, photon, radiation 3886
  • M. Borland, V. Sajaev
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Recently, Zholents et al. proposed applying to the Advanced Photon Source an x-ray compression scheme based on a pair of crab cavities and asymmetric cut crystals. We have explored the feasibility and potential performance of this scheme through simulation. We used the code elegant to perform 6-D tracking, allowing us to characterize the emittance growth, which is mostly a result of sextupoles between the cavities. We also explored tolerances on alignment, phase, and voltage of the cavities; lifetime effects; tradeoffs between cavity frequency and voltage; and performance with slicing alone instead of compression. Our conclusion is that sub-picosecond rms x-ray pulse lengths should be feasible.

RPAE073 Generating Picosecond X-Ray Pulses with Beam Manipulation in Synchrotron Light Sources photon, coupling, simulation, electron 3898
  • W. Guo, M. Borland, K.C. Harkay, V. Sajaev, B.X. Yang
    ANL, Argonne, Illinois
  Funding: Work supported by U. S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.

The length of x-ray pulses generated by storage ring light sources is usually tens of picoseconds. For example, the value is 40 ps rms at the Advanced Photon Source (APS). Methods of x-ray pulse compression are of great interest at the APS. One possible method, per Zholents et al., is to tilt the electron bunch with deflecting rf cavities.* Alternately, we found that the electron bunch can develop a tilt after application of a vertical kick in the presence of nonzero chromaticity. After slicing, the x-ray pulse length is determined by the tilt angle and the vertical beam size. In principal, sub-picosecond pulses can be obtained at APS. To date we have observed 6 ps rms visible light pulses with a streak camera. Efforts are underway to attempt further compression of the x-ray pulse and to increase the brilliance. This method can be easily applied to any storage ring light sources to generate x-ray pulses up to two orders of magnitude shorter than the electron bunch length. In this paper, we will present the theory of bunch tilt, particularly the synchrobetatron coupling and decoherence beam dynamics, and the simulation and the experimental results will also be shown as verification.

*A. Zholents et al., NIM A 425, 385(1999).

RPAE084 Beam Dynamics Aspects of the ASP Booster emittance, closed-orbit, booster, injection 4150
  • S. Friis-Nielsen, S.P. Møller
    Danfysik A/S, Jyllinge
  In the present contribution, beam dynamics aspects of the 3 GeV ASP booster designed and produced by Danfysik A/S are presented. The booster synchrotron, based on a lattice with combined-function magnets, will have a very small emittance of around 30 nm. The dynamical aperture (and admittance) of the booster has been investigated with tracking, and results for different tunes and chromaticities will be presented. Also the reduction in admittance caused by alignment errors of the magnets will be discussed. The nominal tunes and chromaticities are mainly determined by the combined-function magnets to (9.20, 3.25) and (1,1), respectively. Using the trim quadrupoles and sextupoles, the tunes can be adjusted in the ranges (9.05-9.45, 3.05-3.45) and the chromaticities in the range (0-2, 0-2).  
RPAE086 Observation of Coherent Synchrotron Radiation at NewSUBARU radiation, synchrotron-radiation, electron, storage-ring 4188
  • S. Hashimoto, A. Ando
    University of Hyogo, Laboratory of Advanced Science and Technology for Industry (LASTI), Kamigori-cho, Ako-gun, Hyogo
  • Y. Shoji
    LASTI, Ako-gun, Hyogo
  • T. Takahashi
    KURRI, Osaka
  Coherent Synchrotron Radiation from a short electron bunch in a storage ring was observed at NewSUBARU. The energy of electron was 1GeV. The ring was operated with quasi-isochronous mode. The linear momentum compaction factor was smaller than 2 X 10-5 and the bunch length was shorter than 5ps (FWHM). We observed an extremely strong radiation from the weak electron beam, 1μA per bunch.  
RPAE087 Progress of the Synchrotron Light Source ALBA lattice, storage-ring, vacuum, quadrupole 4203
  • D. Einfeld, E. Al-Dmour, J. Campmany, M. Muñoz, M. Pont, F. Pérez
    CELLS, Bellaterra (Cerdanyola del Vallès)
  ALBA will be a third generation synchrotron light source built in Spain near Barcelona. Commissioning of the storage ring is foreseen to start at the end of 2008. The design phase of ALBA is almost completed and the first components are ready to be ordered. A 100 MeV LINAC will inject electrons into a nominal energy booster synchrotron of similar circumference as the storage ring, so that both accelerators will share the same tunnel. The storage ring, working at 3 GeV with a circumference of 268.8 m, has been designed for a maximum current of 400 mA. The lattice is based on an extended DBA structure and has a nominal emittance of 4 nm.rad.The machine has a four fold symmetry with 4 long straight sections (8 m), 12 medium (4.2 m) and 8 short (2.6 m). This report concentrates on recent design developments, component choices and current status. Another paper at this conference deals with accelerator physics issues.  
RPAP008 The CBS–The Most Cost Effective and High Performance Carbon Beam Source Dedicated for a New Generation Cancer Therapy ion, extraction, electron, injection 1108
  • M. Kumada
    NIRS, Chiba-shi
  • B.I. Grishanov, E.B. Leivichev, V.V. Parkhomchuk, F.V. Podgorny, S. Rastigeev, V.B. Reva, A.N. Skrinsky, V.A. Vostrikov
    BINP SB RAS, Novosibirsk
  A Carbon ion beam is a superior tool to x-rays or a proton beam in both physical and biological doses in treating a cancer. A Carbon beam has an advantage in treating radiation resistant and deep-seated tumors. Its radiological effect is of a mitotic independent nature. These features improve hypofractionation, typically reducing the number of irradiations per patient from 35 to a few. It has been shown that a superior QOL(Quality Of Life) therapy is possible by a carbon beam.The only drawback is its high cost. Nevertheless, tens of Prefectures and organizations are eagerly considering the possibility of having a carbon ion therapy facility in Japan. Germany, Austria, Italy, China, Taiwan and Korea also desire to have one.A carbon beam accelerator of moderate cost is about 100 Million USD. With the "CBS" design philosophy, which will be described in this paper, the cost could be factor of 2 or 3 less, while improving its performance more than standard designs. Novel extraction techniques, a new approach to a high intensity beam, a new scanning method of a superμbeam and an extremely light weight carbon rotating gantry will be presented.This new CBS will have an impact on the medical accelerator community.  
RPAP032 Hardware Tracking Related to Compact Medical Pulse Synchrotron dipole, quadrupole, proton, acceleration 2260
  • K. Endo, K. Egawa, Z. Fang
    KEK, Ibaraki
  • S. Yamanaka
    NIRS, Chiba-shi
  A compact 200 MeV proton synchrotron for the radiotherapy is being developed. Dipole and quadrupole magnets were already manufactured and are ready to measure their field properties under the pulse excitation. Preliminary field measurement was already done on the prototype dipole. Small RF cavity with a wide bandwidth (2~18 MHz) was successfully developed. Concerning to the simultaneous pulse operation of these components, there are some issues to be solved beforehand. These are the tracking between dipole field and the quadruple field gradient, the RF frequency generation sensing the dipole current (or field), the sextupole field correction of the dipole and etc. These issues studied experimentally using the dipole current will be presented in conjunction with the progress of the development.  
RPAP046 Real-Time Beam Loss Monitor Display Using FPGA Technology beam-losses, background, monitoring, linac 2914
  • M.R.W. North, A.H. Kershaw
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  This paper outlines the design of a Real-time Beam Loss Monitor Display for the ISIS Synchrotron based at Rutherford Appleton Laboratory (Oxon, UK). Beam loss is monitored using 39 argon filled ionisation chambers positioned around the synchrotron, the levels of which are sampled four times in each cycle. The new BLM display acquires the signals and displays four histograms, each relating to an individual sample period; the data acquisition and signal processing required to build the display fields are completed within each machine cycle (50 Hz). Attributes of the new system include setting limits for individual monitors; displaying over-limit detection, and freezing the display field when a beam trip has occurred. The design is based around a reconfigurable Field Programmable Gate Array, interfacing to a desktop monitor via the VGA standard. Results gained using simulated monitor signals have proven the system.  
RPAP049 Beam Diagnostics with Optical Fiber Optics optics, feedback, synchrotron-radiation, radiation 3040
  • Y. Yin
    Y.Y. Labs, Inc., Fremont, California
  Optical fiber has been widely used for communications. It is a waveguide with very high-frequency bandwidth. Therefore, it has broad applications for high-frequency related signals such as high-energy Accelerator beam signls. Research and developments has been done to measure charged particle beam and synchrotron radiation with optical fiber based instruments developed by the author. The paper will describe and discuss the experiments and testing of charged particle beams and synchrotron radiation that haverecently been performed.  
RPAT012 A Hardware Transverse Beam Frequency Response Simulator feedback, betatron, resonance 1269
  • J. Ning, C.-Y. Tan
    Fermilab, Batavia, Illinois
  Funding: Fermi National Accelerator Lab.

We build an electronical instrument to get the frequency response close to the pattern of transverse beam frequency response. The method is to apply 1)a time delay circuit with ADC, FIFO RAM and DAC; 2)a phase shift circuit which is an all pass filter with adjustable phase shift in the frequency range of 25kHz to 30kHz; in a feedback loop of 3)a commutating filter which is a high Q band pass filter. We can dynamically adjust the center frequency, the side band distance during the testing. With this instrument, some beam instruments can be tested without using the real beam.

RPAT013 Signal Processing for Longitudinal Parameters of the Tevatron Beam proton, antiproton, emittance, pick-up 1362
  • S. Pordes, J.L. Crisp, B.J. Fellenz, R.H. Flora, A. Para, A.V. Tollestrup
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

The time profiles of the bunches in the Tevatron are obtained by sampling the output of a resistive wall current monitor with a 5GS/s, 2GHz bandwidth, Lecroy 6200 oscilloscope. The techniques for removing the effect of cable dispersion and for extending the dynamic range of the data by splitting the signal and using two input channels at different gains are described. The algorithms for taking these data in the time domain and deriving the momentum spread and longitudinal emittance are also given.

RPAT015 First Results of a Digital Beam Phase Monitor at the Tevatron proton, antiproton, controls, injection 1428
  • J.-P. Carneiro, S. U. Hansen, A. Ibrahim, V.D. Shiltsev, J. Steimel, R.C. Webber
    Fermilab, Batavia, Illinois
  A digital Beam Phase Monitor has been installed on the Tevatron ring. This device will be mainly use to diagnose the energy oscillations of each of the 36 × 36 protons and antiprotons bunches as well as to study the transient beam loading. The first results obtained from the Beam Phase Monitor will be presented on the paper.  
RPAT036 Measurement of the Intensity of the Beam in the Abort Gap at the Tevatron Utilizing Synchrotron Light radiation, collider, proton, synchrotron-radiation 2440
  • R. Thurman-Keup, E. Lorman, T. Meyer, S. Pordes
    Fermilab, Batavia, Illinois
  • S. De Santis
    LBNL, Berkeley, California
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the U.S. Department of Energy.

The beam bunches in the Tevatron are arranged to provide gaps in time for the abort kickers to ramp to full field. The presence of even a small fraction (few 10-4)of the beam in the abort gaps can induce quenches of the superconducting magnets and inflict severe radiation damage on the silicon detectors of the experiments. Techniques for calibrating and measuring the intensity of the beam in the abort gap using synchrotron light and a gated photomultiplier tube are described. Measurements of the evolution and longitudinal profile of the beam in the abort gap are presented.

RPAT048 An X-Ray BPM and Accompanying Electronics diagnostics, photon, feedback, synchrotron-radiation 3019
  • S.R. Marques, O.R. Bagnato, Bombacini, F.O. Bombacini, M.J. Ferreira, H. J. Onisto
    LNLS, Campinas
  Recent experiments at the LNLS Ultra Violet and X-Ray beam lines are pushing on the Synchrotron Radiation beam position stability requirements. In the direction of having photon Beam Position Monitor integrated to the orbit closed loop control system, we developed a staggered blades XR BPM and a four channel current measurement electronics. The BPM mechanical design was based on the SR masks previously developed and currently in use at the beam lines front end. By this design reuse, in addition to using an already available and well-tested, low cost construction technique, we expect to have a simple replacement of the SR masks by the XR BPMs in most of the beam lines, shortening the downtimes and the number of line parts to be replaced. We describe the design and the resulting performance of the XR BPM and the accompanying electronics.  
RPAT053 Movement of BPMs Due to Thermal Stress in KEKB pick-up, sextupole, radiation, luminosity 3253
  • M. Tejima, A. Arinaga, H. Fukuma, S. Hiramatsu, T. Ieiri, I. Ishii, M. Tobiyama
    KEK, Ibaraki
  Movement of Beam Position Monitors (BPM) due to thermal stress in high beam current operation is observed in KEKB. For high luminosity operation of KEKB, the beam current as high as 1.6A is accumulated in the positron ring and a precise control of the beam orbit based on the BPM system is required. Though the every BPM chamber is fixed firmly on a support of each quadrupole magnet, the BPM chamber moves several hundred microns from the setting position depending on the beam current due to beam pipe heating by strong synchrotron light irradiation. Such movement introduces an unavoidable offset error in the BPM measurement, and is a serious problem not only for KEKB but also for the next generation of B-factory operated with extremely high beam current. We report the measurement of the movement by distance sensors and an attempt to correct the BPM offset error in real-time operation.  
RPAT059 The SRI Beam Size Monitor Developed at NSRRC photon, radiation, diagnostics, synchrotron-radiation 3465
  • T.C. Tseng, J.-R. Chen, H.C. Ho, C.-K. Kuan, C.J. Lin, S.Y. Perng, D.-J. Wang, J. Wang
    NSRRC, Hsinchu
  A beam size monitor based on the synchrotron radiation interferometer (SRI) was installed in the NSRRC TLS. This monitor consists of a simple diagnostic beamline with a water-cooled beryllium mirror inside and a detecting optical system for both vertical and horizontal beam size measurement. The beam sizes measured are 48 micron and 160 micron respectively and are more close to the theoretical values than the synchrotron image monitor. Comparing with other monitors, at least 1 micron beam size variation is detectable. To minimize the thermal effect, the mirror is located far away from the source point and closed to the detecting optical system. The thermal distortion of the mirror is quite small measured by a portable long trace profiler (LTP) and agrees with the simulating analysis. The detailed monitor system design and testing results are presented in this paper.  
RPAT063 A Bunch-By-Bunch and Turn-By-Turn Instrumentation Hardware Upgrade for CESR-c luminosity, electron, positron, instrumentation 3597
  • M.A. Palmer, J. Dobbins, C.R. Strohman, E. Tanke
    CESR-LEPP, Ithaca, New York
  Funding: Work supported by the National Science Foundation.

A key factor in the colliding beam performance of the Cornell Electron Storage Ring (CESR) is the impact of parasitic beam-beam interactions between bunches in the two beams as they follow their electrostatically separated orbits in a single vacuum chamber. In order to better investigate the differential performance of bunches in CESR, instrumentation electronics has been developed to allow acquisition of turn-by-turn data from multiple bunches simultaneously. The electronics consists of a standardized digital board centered around an Analog Devices TigerSHARC family digital signal processor, a communications interface, and an interface to the CESR Precision Timing System. Mated to these components is an analog front end and digitizer board which is customized for the particular diagnostic device of interest. Front ends have been developed for beam position monitor, luminosity monitor, and beam profile monitor applications. We describe the design and characterization of this new hardware.

RPAT068 Proposed Diagnostics for the NSLS-II electron, injection, radiation, diagnostics 3760
  • I.P. Pinayev, S.L. Kramer, J. Rose, T.V. Shaftan
    BNL, Upton, Long Island, New York
  Funding: The U.S. Department of Energy under contract No. DE-AC02-98CH10886.

The National Synchrotron Light Source is performing R&D of a new 3 GeV electron storage ring to be used for the facility upgrade. To satisfy the demands for the brightness and stability of the future light source a state-of-the-art diagnostics system is a necessity. We present our preliminary design with focus on the requirements for instrumentation and technical solutions to achieve them.

RPAT075 Optical Synchronization Systems for Femtosecond X-Ray Sources laser, polarization, linac, scattering 3958
  • R.B. Wilcox, J.W.  Staples
    LBNL, Berkeley, California
  • R. Holzwarth
    Menlo Systems GmbH, Martinsried
  Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under the Department of Energy Contract No. DE-AC03-76SF00098.

In femtosecond pump/probe experiments using short x-ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error. For the sub-100fs range we use an amplitude modulated CW laser at 1GHz to transmit RF phase information, and control the delay through a 100m fiber by observing the retroreflected signal. Initial results show 40fs peak-to-peak error above 10Hz, and 200fs long term drift, mainly due to amplitude sensitivity in the analog mixers. For the sub-10fs range we will lock two single-frequency lasers separated by several teraHertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes. For attosecond synchronization we propose a stabilized, free space link using bulk lens waveguides and high peak power ultrashort pulses.

RPAT080 The SPEAR 3 Diagnostic Beamlines coupling, radiation, emittance, optics 4057
  • W.J. Corbett, C. Limborg-Deprey, W.Y. Mok, A. Ringwall
    SLAC, Menlo Park, California
  Funding: Work supported in part by DOE contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.

SPEAR 3 is equipped with an x-ray pinhole camera and a visible/UV beam line to evaluate electron beam properties. The pinhole camera has a 30 x 25 micron Ta aperture and 60% image demagnification on a phosphor screen. The image is captured by a National Instruments frame-grabber on a remote computer with a parallel video signal for control room monitoring. The visible/UV beam line features a horizontal ± 0.3 mrad ‘cold finger’ to remove the x-ray core of the beam. The remaining visible/UV light is deflected 18 degrees onto an optical bench where it is focused via refractive Cassegrain optics. The beam is then split into parallel optics for gated- and streak camera measurements. This paper describes the experimental set up and preliminary measurements obtained with both systems.

RPAT090 The Study of New Signal Processing Technique in Photon Beam Position Monitors photon, synchrotron-radiation, radiation, monitoring 4239
  • S.F. Lin, H. Gao, P. Lu, B. Sun, J. Wang
    USTC/NSRL, Hefei, Anhui
  A log-ratio signal processing technique in photon beam position monitors (PBPM) was presented in this paper. The main performances (e.g. sensitivity, position offset and linearity range) of split PBPM and a pair of wires PBPM were analyzed , and the result of the measurement fit well with the theory. An inexpensive logarithmic amplifier chip which can measure photon currents from 0.1nA to 3.5mA was used in electronic circuits. The logarithmic ratio of the signal amplitudes from the PBPM provides a real-time analog signal that has wider linearity range and higher bandwidth than signal processing technique.

Supported by Natural Science Foundation of China (10275062) and CAS Knowledge Innovation Project (KY4206).

ROPB007 3-D Parallel Simulation Model of Continuous Beam-Electron Cloud Interactions simulation, electron, betatron, emittance 549
  • A.F. Ghalam, T.C. Katsouleas
    USC, Los Angeles, California
  • E. Benedetto, F. Zimmermann
    CERN, Geneva
  • V.K. Decyk, C. Huang, W.B. Mori
    UCLA, Los Angeles, California
  • G. Rumolo
    GSI, Darmstadt
  A 3D Particle-In-Cell model for continuous modeling of beam and electron cloud interaction in a circular accelerator is presented. A simple model for lattice structure, mainly the Quadruple and dipole magnets and chromaticity have been added to a plasma PIC code, QuickPIC, used extensively to model plasma wakefield acceleration concept. The code utilizes parallel processing techniques with domain decomposition in both longitudinal and transverse domains to overcome the massive computational costs of continuously modeling the beam-cloud interaction. Through parallel modeling, we have been able to simulate long-term beam propagation in the presence of electron cloud in many existing and future circular machines around the world. The exact dipole lattice structure has been added to the code and the simulation results for CERN-SPS and LHC with the new lattice structure have been studied. Also the simulation results are compared to the results from the two macro-particle modeling for strong head-tail instability. It is shown that the simple two macro-particle model can capture some of the physics involved in the beam- electron cloud interaction qualitatively.  
RPPE006 Air Temperature Analysis and Control Improvement for the Storage Ring Tunnel storage-ring, simulation, synchrotron-radiation, lattice 1027
  • J.-C. Chang, Z.-D. Tsai
    NSRRC, Hsinchu
  • J.-R. Chen
    NTHU, Hsinchu
  • M. Ke
    NTUT, Taipei
  The stability of the electron beam orbit had been observed to be sensitive to the utility conditions. The stability of air temperature in the storage ring tunnel is one of the most critical factors. Accordingly, a series of air conditioning system upgrade studies and projects have been conducted at the Taiwan Light Source (TLS). Computational fluid dynamics (CFD) is applied to simulate the flow field and the spatial temperature distribution in the storage ring tunnel. The circumference and the height of the storage tunnel are 120m and 2.8m, respectively. The temperature data and the flow rates at different locations around the storage ring tunnel are collected as the boundary conditions. The k-epsilon turbulence model is applied to simulate the flow field in the three dimensional space. The global air temperature variation related to time in the storage ring tunnel is currently controlled within ±0.1 degree C. However, the temperature difference between two different locations is as high as 2 degree C. Some measures improving the temperature uniformity will be taken according to the CFD simulation results.  
RPPE007 High Precision Temperature Control and Analysis of RF Deionized Cooling Water System synchrotron-radiation, radiation, coupling, instrumentation 1057
  • Z.-D. Tsai, J.-C. Chang, C.-Y. Liu
    NSRRC, Hsinchu
  • J.-R. Chen
    NTHU, Hsinchu
  Previously, the Taiwan Light Source (TLS) has proven the good beam quality mainly depends on the utility system stability. A serial of efforts were devoted to these studies. Further, a high precision temperature control of the RF deionized cooling water system will be achieved to meet the more critical stability requirement. The paper investigates the mixing mechanism through thermal and flow analysis and verifies the practical influences. A flow mixing mechanism and control philosophy is studied and processed to optimize temperature variation which has been reduced from ±0.1? to ±0.01?. Also, the improvement of correlation between RF performance and water cooling stability will be presented.  
RPPE037 The Vacuum System for PETRA III radiation, vacuum, dipole, undulator 2473
  • M. Seidel, R. Bospflug, J. Boster, W. Giesske, U. Naujoks, M. Schwartz
    DESY, Hamburg
  It is planned to rebuild the storage ringe PETRA II, presently used as pre-accelerator of HERA, into a high performance synchrotron light source. By making use of the large circumference and the installation of damping wigglers it will be possible to achieve exceptionally small emittances in the new storage ring. The requirements for the vacuum system are more advanced in the new storage ring as well. Besides the goal to achieve low pressures and fast conditioning times a major key for the new ring is a very high orbit stability which implies high thermal stability of BPM's and other vacuum components. We describe the basic concepts for chamber layout, pumping schemes, synchrotron radiation absorption and mechanical stability for the standard arcs and the experimental octant. Furthermore the expected performance will be discussed.  
RPPE043 Ultrathin Polyimide-Stainless Steel Heater for Vacuum System Bake-Out radiation, vacuum, insertion, simulation 2744
  • C. Rathjen, S. Blanchard, B. Henrist, K. Koelemeijer, B. Libera, P. Lutkiewicz
    CERN, Geneva
  Space constraints in several normal conducting magnets of the LHC required the development of a dedicated permanent heater for vacuum chamber bake-out. The new heater consists of stainless steel bands inside layers of polyimide. The overall heater thickness is about 0.3 mm. The low magnetic permeability is suitable for applications in magnetic fields. The material combination allows for temperatures high enough to activate a NEG coating. Fabrication is performed in consecutive steps of tape wrapping. Automation makes high volume production at low costs possible. About 800 m of warm vacuum system of the long straight sections of the LHC will be equipped with the new heater. This paper covers experience gained at CERN from studies up to industrialization.  
RPPE044 Vacuum Modifications for the Installation of a New CESR-c Fast Luminosity Monitor vacuum, dipole, luminosity, photon 2836
  • Y. Li, Y. He, M.A. Palmer
    Cornell University, Department of Physics, Ithaca, New York
  Funding: Work supported by the National Science Foundation.

In order to improve luminosity tuning and maintenance for the CLEO-c high energy physics (HEP) program at the Cornell Electron Storage Ring (CESR), a luminosity monitor using photons from radiative Bhabha events has been installed in the CESR ring. Over 10 meters of CESR vacuum chambers near the interaction region were modified to accommodate this new device. The vacuum modifications were designed to meet two criteria. First, the new vacuum chambers had to provide sufficient horizontal and vertical aperture for photons originating from the IP over a wide range of colliding beam conditions. Secondly, the new vacuum chambers required adequate safety margins for operation at beam energies up to 5.3 GeV for Cornell High Energy Synchrotron Source running. In order to be certain that the vacuum modifications would not give rise to any localized pressure bumps, a detailed calculation of the expected vacuum pressure distribution due to synchrotron radiation flux was carried out. Careful design and planning enabled a successful installation and resumption of CESR operations in record time.

RPPE056 Status of the NSRL Storage Ring UHV System After Project-II vacuum, storage-ring, radiation, synchrotron-radiation 3334
  • Y. Wang, L. Fan, C. Y. Guan, D. M. Jiang, J. P. Wang, W. Wei, F. Y. Zhao
    USTC/NSRL, Hefei, Anhui
  The NSRL project-II has been finished in December 2004. The UHV system of storage ring has undergone improvement and now provide long beam lifetime and stable operations, the average pressure of ring is better than 2 × 10-8 Pascal without beam and 1 × 10-7 Pascal with beam, The typical beam lifetime is 12 hours at 300 mA and 800 MeV without wiggler and 8 hours at 300 mA and 800 MeV with wiggler on. The improvements and status of NSRL storage ring are described in this paper.  
RPPE058 Successful RF and Cryogenic Tests of the SOLEIL Cryomodule electron, insertion, coupling, insertion-device 3438
  • P. Marchand, M. Louvet, M. Louvet-Monsanglant, K. Tavakoli, C. Thomas-Madec
    SOLEIL, Gif-sur-Yvette
  • L. Arnaudon, O. Brunner, R. Losito, P. Maesen, E. Montesinos, G. Pechaud, M.P. Prax
    CERN, Geneva
  • P. Bosland, P. Bredy, S. Chel, G. Devanz
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  In the Storage Ring (SR) of the Synchrotron SOLEIL light source, two cryomodules will provide the maximum power of 600 kW required at the nominal energy of 2.75 GeV with the full beam current of 500 mA and all the insertion devices. A cryomodule prototype, housing two 352 MHz superconducting single-cell cavities with strong damping of the Higher Order Modes has been built and successfully tested in the ESRF. Even though the achieved performance (3 MV and 380 kW) does meet the SOLEIL requirement for the first year of operation, it was decided to upgrade the cryomodule prototype before its implementation in the SR. Modifications of the internal cryogenic system as well as the input power and dipolar HOM couplers required complete disassembling, reassembling and testing of the cryomodule, which were carried out at CERN. This refurbishment program, which was achieved in the framework of a collaboration between SOLEIL, CEA and CERN, is reported in this paper. A second cryomodule, similar to the modified prototype, is under manufacturing and will be implemented in the SR by the end of 2006.  
RPPE068 A Magnetostrictive Tuning System for Particle Accelerators vacuum, radio-frequency, monitoring, background 3762
  • C.-Y. Tai, J. Cormier, W. J. Espinola, Z. Han, C.H. Joshi, A. Mavanur, L.M. Racz
    Energen, Inc., Lowell, Massachusetts
  • E. Daly, G.K. Davis
    Jefferson Lab, Newport News, Virginia
  • K.W. Shepard
    ANL, Argonne, Illinois
  Funding: This work is supported by DOE SBIR Program DE-FG02-03ER83648.

Energen, Inc. has designed, built, and demonstrated several fast and slow tuners based on its magnetostrictive actuators and stepper motor. These tuners are designed for Superconducting Radio Frequency (SRF) cavities, which are important structures in particle accelerators that support a wide spectrum of disciplines, including nuclear and high-energy physics and free electron lasers (FEL). In the past two years, Energen’s work has focused on magnetostrictive fast tuners for microphonics and Lorentz detuning compensation on elliptical-cell and spoke-loaded cavities, including the capability for real-time closed-loop control. These tuners were custom designed to meet specific requirements, which included a few to 100 micron stroke range, hundreds to kilohertz operation frequency, and cryogenic temperature operation in vacuum or liquid helium. These tuners have been tested in house and at different laboratories, such as DESY, Argonne National Lab, and Jefferson Lab. Some recent results are presented in this paper.

RPPP036 A Test Facility for the International Linear Collider at SLAC End Station A for Prototypes of Beam Delivery and IR Components insertion, linear-collider, collider, wiggler 2461
  • M. Woods, R.A. Erickson, J.C. Frisch, C. Hast, R.K. Jobe, L. Keller, T.W. Markiewicz, T.V.M. Maruyama, D.J. McCormick, J. Nelson, N. Phinney, T.O. Raubenheimer, M.C. Ross, A. Seryi, S. Smith, Z. Szalata, P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  • D.A.-K. Angal-Kalinin, C.D. Beard, F.J. Jackson, A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Arnold
    University of Massachusetts, Amherst
  • D. Bailey
  • R.J. Barlow, G.Yu. Kourevlev, A. Mercer
    UMAN, Manchester
  • S.T. Boogert, A. Liapine, S. Malton, D.J. Miller, M.W. Wing
    UCL, London
  • P. Burrows, G.B. Christian, C.C. Clarke, A.F. Hartin, S. Molloy, G.R. White
    Queen Mary University of London, London
  • D. Burton, N. Shales, J. Smith, A. Sopczak, R. Tucker
    Microwave Research Group, Lancaster University, Lancaster
  • D. Cussans
    University of Bristol, Bristol
  • C. Densham, J. Greenhalgh
    CCLRC/DL, Daresbury, Warrington, Cheshire
  • M.H. Hildreth
    Notre Dame University, Notre Dame, Iowa
  • Y.K. Kolomensky
    UCB, Berkeley, California
  • W.F.O. Müller, T. Weiland
    TEMF, Darmstadt
  • N. Sinev, E.T. Torrence
    University of Oregon, Eugene, Oregon
  • M.S. Slater, M.T. Thomson, D.R. Ward
    University of Cambridge, Cambridge
  • Y. Sugimoto
    KEK, Ibaraki
  • S.W. Walston
    LLNL, Livermore, California
  • N.K. Watson
    Birmingham University, Birmingham
  • I. Zagorodnov
    DESY, Hamburg
  • F. Zimmermann
    CERN, Geneva
  Funding: U.S. Department of Energy.

The SLAC Linac can deliver damped bunches with ILC parameters for bunch charge and bunch length to End Station A (ESA). A 10Hz beam at 28.5 GeV energy can be delivered to ESA, parasitic with PEP-II operation. During the engineering design phase for the ILC over the next 5 years, we plan to use this facility to prototype and test key components of the Beam Delivery System (BDS) and Interaction Region (IR). We discuss our plans for this ILC Test Facility and preparations for carrying out experiments related to Collimator Wakefields, Materials Damage Tests and Energy Spectrometers. We also plan an IR Mockup of the region within 5 meters of the ILC Interaction Point to investigate effects from backgrounds and beam rf higher-order modes (HOMs).

RPPP048 Beam Collimation and Machine-Detector Interface at the International Linear Collider photon, collimation, radiation, synchrotron-radiation 2995
  • N.V. Mokhov, A.I. Drozhdin, M.A. Kostin
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Association, Inc., under contract DE-AC02-76CH03000 with the U.S. Department of Energy.

Synchrotron radiation, spray from the dumps and extraction lines, beam-gas and beam halo interactions with collimators and other components in the ILC beam delivery system create fluxes of muons and other secondaries which can exceed the tolerable levels at a detector by a few orders of magnitude. It is shown that with a multi-stage collimation system, magnetized iron spoilers which fill the tunnel and a set of masks in the detector, one can hopefully meet the design goals. Results of modeling with the STRUCT and MARS15 codes of beam loss and energy deposition effects are presented in this paper. We concentrate on collimation system and mask design and optimization, short- and long-term survivability of the critical components (spoilers, absorbers, magnets, separators, dumps), dynamic heat loads and radiation levels in magnets and other components, machine-related backgrounds and damage in collider detectors, and environmental aspects (prompt dose, ground-water and air activation).

RPPT016 Effects of Wakefields on the Microbunching Instabilities at PAL-XFEL linac, impedance, space-charge, synchrotron-radiation 1473
  • E.-S. Kim
    PAL, Pohang, Kyungbuk
  We present effects of the wakefields in accelerating structures of the S-band linac on the microbunching instabilties at the PAL-XFELs. Analytical calculations are performed to investigate the gains of the instabilities in the accelerator system for the PAL-XFELs.  
RPPT024 Doubling the Intensity of an ERL Based Light Source linac, undulator, wiggler, electron 1862
  • A. Hutton
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by the U.S. DOE under Contract No. DE-AC05-84ER40150.

A light source based on an Energy Recovered Linac (ERL)* consists of a superconducting linac and a transfer line that includes wigglers and undulators to produce the synchrotron light. The transfer line brings the electrons bunches back to the beginning of the linac so that their energy can be recovered when they traverse the linac a second time, ????out of phase. There is another interesting condition when the length of the transfer line is (n±1/4) ?. In this case, the electrons drift through on the zero RF crossing, and make a further pass around the transfer line, effectively doubling the circulating current in the wigglers and undulators. On the third pass through the linac, they will be decelerated and their energy recovered. The longitudinal focusing at the zero crossing is a problem, but it can be canceled if the drifting beam sees a positive energy gradient for the first half of the linac and a negative gradient for the second half (or vice versa). This paper presents a proposal to use a double chicane at the center of the linac to provide this focusing inversion for the drifting beam while leaving the accelerating and decelerating beams on crest.

*G. R. Neil et al., Phys. Rev. Let. 84, 662 2000.

RPPT033 Potential Use of eRHIC’s 10-to-20 GeV ERL for FELs and Light Sources radiation, electron, linac, synchrotron-radiation 2266
  • V. Litvinenko, I. Ben-Zvi
    BNL, Upton, Long Island, New York
  Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy.

One of the designs of a future electron-hadron collider, eRHIC, is based on a 5-10 GeV high current energy-recovery linac (ERL) with possible extension of its energy to 20 GeV. This ERL will operate with high brightness electron beams, which naturally match requirements for X-ray FELs and other next generation light sources. In this paper we discuss possible scenarios of using the eRHIC ERL in parasitic and dedicated mode for SASE, HGHG and oscillator X-ray FELs.

*http://www.agsrhichome.bnl.gov/eRHIC/, Appendix A: Linac-Ring Option

RPPT046 Development and Application of Bunch-by-Bunch Measurement System of HLS damping, betatron, single-bunch, pick-up 2932
  • J.H. Liu, Y.J. Pei, B. Sun, J.H. Wang, Y.L. Yang, K. Zheng
    USTC/NSRL, Hefei, Anhui
  This paper is intended to present the newly implemented wideband (100MHz) bunch oscillation measurement system, which is in nature a different method from the narrow-band (<5MHz) facilities employed before. Basic formalism and implementation details of the system is introduced to illustrate the function of observing coupled bunch instabilities in time and frequency domain. The designed function includes detecting of transverse oscillation, synchrotron phase oscillation, as well as bunch filling pattern. Some diagnostics results of machine instabilities and application of this system are also discussed.  
RPPT067 A High-Power Target Experiment target, proton, factory, interaction-region 3745
  • H.G. Kirk, S.A. Kahn, H. Ludewig, R. Palmer, V. Samulyak, N. Simos, T. Tsang
    BNL, Upton, Long Island, New York
  • J.R.J. Bennett
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • T.W. Bradshaw, P. Drumm, T.R. Edgecock, Y. Ivanyushenkov
    CCLRC/RAL, Chilton, Didcot, Oxon
  • I. Efthymiopoulos, A. Fabich, H. Haseroth, F. Haug, J. Lettry
    CERN, Geneva
  • T.A. Gabriel, V.B. Graves, J.R. Haines, P.T. Spampinato
    ORNL, Oak Ridge, Tennessee
  • Y. Hayato, K. Yoshimura
    KEK, Ibaraki
  • K.T. McDonald
    PU, Princeton, New Jersey
  Funding: U.S. Department of Energy.

We describe an experiment designed as a proof-of-principle test for a target system capable of converting a 4 MW proton beam into a high-intensity muon beam suitable for incorporation into either a neutrino factory complex or a muon collider. The target system is based on exposing a free mercury jet to an intense proton beam in the presence of a high strength solenoidal field.

RPPT075 Generation of Femtosecond Electron and Photon Pulses radiation, electron, photon, lattice 3946
  • C. Thongbai, V. Jinamoon, Mr. Kangrang, K. Kusoljariyakul, S. Rimjaem, J. Saisut, T. Vilaithong
    FNRF, Chiang Mai
  • M.W. Rhodes, P. Wichaisirimongkol
    IST, Chiang Mai
  • H. Wiedemann
    SLAC, Menlo Park, California
  Funding: We are grateful to the Thailand Research Fund, the National Research Council of Thailand, the Thai Royal Golden Jubilee Scholarship, the U.S. Department of Energy, and the Hansen Experimental Physics laboratory of Stanford University.

Femtosecond electron and photon pulses become a tool of interesting important to study dynamics at molecular or atomic levels. Such short pulses can be generated from a system consisting of an RF-gun with a thermionic cathode, an alpha magnet as a magnetic bunch compressor, and a linear accelerator. The femtosecond electron pulses can be used directly or used as sources to produce electromagnetic radiation of equally short pulses by choosing certain kind of radiation pruduction processes. At the Fast Neutron Research Facility (Thailand), we are especially interested in production of radiation in Far-infrared and X-ray regime. In the far-infrared wavelengths which are longer than the femtosecond pulse length, the radiation is emitted coherently producing intense radiation. In the X-ray regime, development of femtosecond X-ray source is crucial for application in ultrafast science.

ROPA002 CLS: A Fully Open-Source Control System controls, power-supply, storage-ring, linac 136
  • E. Matias, R. Berg, T. Johnson, R. Tanner, T. Wilson, G. Wright, H.Z. Zhang
    CLS, Saskatoon, Saskatchewan
  The Canadian Light Source is one of the first major accelerator facility to adopt a fully open source control system. The control system is based on Experimental Physics and Industrial Control System (EPICS) in use at may other facilities. From the outset CLS utilised RTEMS and Linux as the underlying operating systems for real-time control computers, operator interface computers and servers. When communicating with PLC and other intelligent devices CLS has also adopted a policy of using open communications protocols where possible. Combined these strategies have lead to a system that can easily evolve over the life of the facility without being tied to specific hardware or software suppliers. The operational experience over the past few years has indicates the selected architecture is sufficiently robust and reliable.  
ROPA003 Present Status of the J-PARC Control System linac, proton, rfq, power-supply 302
  • T. Katoh, K.  Furukawa, N. Kamikubota, H. Nakagawa, J.-I. Odagiri, G.S. Shen, Y. Takeuchi, N. Yamamoto, M. Yoshii
    KEK, Ibaraki
  • H. Sakaki, H. Sako, H. Takahashi, F. Tamura, H. Yoshikawa
    JAERI, Ibaraki-ken
  Construction of the J-PARC control system is in progress and the present status is reported. The control system is based on EPICS tool-kit used in KEKB and other accelerator control systems at KEK. The control hardware and network system for Linac and RCS(Rapid Cycling Synchrotron) have been installed and software is under development now. The operation of Linac is expected in next year. The test of the first part of the accelerator complex; e.g. ion source, RFQ and the first DTL(20 MeV) were done at KEK site. Development of various software such as device drivers for the new equipment, device support routines, and some application programs for operators were also developed.  
ROPA004 CEBAF Control Room Renovation controls, plasma, monitoring, linac 378
  • M. Spata, A. Cuffe, H. Fanning, T.C.O. Oren
    Jefferson Lab, Newport News, Virginia
  The Machine Control Center at Jefferson Lab's Continuous Electron Beam Accelerator Facility was initially constructed in the early 1990s and based on proven technology of that era. Through our experience over the last 15 years and in our planning for the facilities 12 GeV upgrade we reevaluated the control room environment to capitalize on emerging visualization and display technologies and improve on workflow processes and ergonomic attributes. This effort also sets the foundation for the redevelopment of the accelerator's control system to deliver high reliability performance with improvements in beam specifications management and information flow. The complete renovation was performed over a three-week period with no interruption to beam operations. We present the results of this effort.  
ROPA005 High Level Control Applications for SOLEIL Commissioning and Operation booster, power-supply, storage-ring, linac 481
  • L.S.N. Nadolski, J. Chinkumo, K. Ho, N.L. Leclercq, M.O. Ounsy, S. Petit
    SOLEIL, Gif-sur-Yvette
  Funding: Synchrotron SOLEIL

The SOLEIL control system, namely TANGO developed in collaboration with ESRF, is now mature and stable. TANGO has also been chosen now by several other laboratories. High-level control applications implemented in the control room for the storage ring, the two transfer lines, and the booster will be described in this paper. Three kinds of tools for commissioning are used. First the generic TANGO tools (alarms, simple graphical control applications), which allow us to control in a simple way any TANGO Device Server. Secondly a Matlab Middle Layer (adapted from ALS and SPEAR3): Matlab is fully interconnected with TANGO; it is used primarily for writing Physics control applications. Finally Globalscreen, a commercial SCADA software devoted for building operation applications has been selected (panels for controlling or displaying setpoint, readback values, status of equipments). In addition an overview of the historical and short-term databases for the accelerators will be given. They have been developed in house and tested during the first commissioning.

ROPC002 J-PARC Commissioning Results linac, injection, proton, rfq 220
  • K. Hasegawa
    JAERI, Ibaraki-ken
  The J-PARC (Japan Proton Accelerator Research Complex)comprises a 400-MeV linac, a 3-GeV rapid-cycling synchrotron (RCS), a 50-GeV main ring synchrotron (MR) and experimental facilities. A peak current of 30 mA was accelerated up to 20 MeV of the DTL beam commissioning at the KEK site. The buildings and conventional facilities will be completed in succession in the Japanese Fiscal Year 2005, when the installation of the accelerator components will be actually started at Tokai site. The beam commissioning of the 181 MeV linac will be started in September, 2006, followed by the RCS and MR beam commissioning. To achieve the high beam power with low beam loss, the J-PARC accelerators are based on many newly developed technologies; pi-mode stabilizing loops in the RFQ, RF choppers in the medium energy beam transport, magnetic alloy loaded RF cavities in the synchrotrons, etc. The recent results of the developments of these new technologies, the present construction status and the commissioning schedule will be presented.  
FPAE005 Characteristics of Injected Beam at HIMAC Synchrotron injection, resonance, simulation, survey 952
  • T.H. Uesugi, T. Furukawa, K. Noda, S. Shibuya
    NIRS, Chiba-shi
  At the HIMAC synchrotron, we have carried out the tune survey with the lifetime measurement in order to obtain the high intensity. Under the relatively high intensity, it was observed that a part of the circulating beam was lost due to the coherent oscillation in both the horizontal and the vertical direction. Taking account of the tune shift and spreads, the working point was optimized so as to avoid resonance line. We will describe the experimental result.  
FPAE007 A Project of the 2.5 GeV Booster-Synchrotron in BINP booster, injection, extraction, quadrupole 1039
  • V.A. Kvardakov, V. Barbashin, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.I. Mishnev, V. Petrov, A.N. Skrinsky, V.V. Smaluk, I. Zemlyansky
    BINP SB RAS, Novosibirsk
  A project of the 2.5 GeV booster synchrotron to provide effective injection of electron and positron beams into VEPP-2000 and VEPP-4M storage rings, and for future facilities, is developing in BINP. The beams are injected to synchrotron at 510 MeV energy from a damping ring, which is the part of the new injection facility. In this report, the synchrotron parameters are presented, the basic systems are briefly described.  
FPAE009 Bunched Beam Cooling in the Fermilab Recycler emittance, collider, bunching, scattering 1153
  • D.V. Neuffer, D.R. Broemmelsiek, A.V. Burov, S. Nagaitsev
    Fermilab, Batavia, Illinois
  Stochastic cooling with bunched beam in a linear bucket has been obtained and implemented operationally in the fermilab recycler. In this implementation the particle bunch length is much greater than the cooling system wavelengths. The simultaneous longitudinal bunching enables cooling to much smaller longitudinal emittances than the coasting beam or barrier bucket system. Characteristics and limitations of bunched beam stochastic cooling are discussed.  
FPAE020 Induction Acceleration of a Single RF Bunch in the KEK PS induction, acceleration, focusing, booster 1679
  • K. Takayama, D.A. Arakawa, Y.A. Arakida, S. Igarashi, T. Iwashita, T. Kono, E. Nakamura, M. Sakuda, H. Sato, Y. Shimosaki, M.J. Shirakata, T. Sueno, K. Torikai, T. Toyama, M. Wake, I. Yamane
    KEK, Ibaraki
  • K. Horioka
    TIT, Yokohama
  • A.K. Kawasaki, A. Tokuchi
    NICHICON, Shiga
  • J. Kishiro
    JAERI/LINAC, Ibaraki-ken
  • K. Koseki
    GUAS/AS, Ibaraki
  • M.S. Shiho
    JAERI/NAKA, Ibaraki-ken
  • M. Watanabe
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  A single bunch trapped in an RF bucket was accelerated by induction devices from 500 MeV to 8GeV beyond transition energy in the KEK-PS. This is the first demonstration of induction acceleration in a high energy circular ring. The acceleration was confirmed by measuring a temporal evolution of the RF phase through an entire acceleration.* Key devices in an induction acceleration system are an induction accelerating cavity capable of generating an induced voltage of 2kV/cell, a pulse modulator to drive the cavity (switching driver), and a DSP system to control gate signals for switching. Their remarkable characteristics are its repetition ratio of about 1MHz and duty factor of 50%. All devices have been newly developed at KEK so as to meet this requirement. The pulse modulator employing MOSFETs as switching elements is connected with the accelerating cavity through a long transmission cable in order to avoid a high-dose irradiation in the accelerator tunnel. The induction system has been running beyond more than 24 hours without any troubles. The paper will take an introductive role for related other 6 papers too, which describe more technical aspects and novel beam physics associated with the induction acceleration.

*K.Takayama et al., submitted to Phys. Rev. Lett., http://www.arxiv.org/pdf/physics/0412006.

FPAE023 Direct Antiproton Deceleration in the Fermilab Proton Driver antiproton, proton, simulation, H-minus 1817
  • G.P. Jackson, S.D. Howe
    Hbar Technologies, LLC, West Chicago, Illinois
  The Fermilab Proton Driver is an 8 GeV kinetic energy H- linear accelerator proposed as a new source of high brightness protons for the Main Injector. The Recycler ring is an 8 GeV antiproton storage ring that resides in the same tunnel as the Main Injector. This paper describes a scenario wherein the current Main Injector proton injection kickers and Lambertson magnet are moved vertically into the Recycler ring to enable antiproton extraction toward the Proton Driver. By employing a pair of intermediate vertical bends at the appropriate vertical betatron phase advance, the vertical dispersion into the Proton Driver can be eliminated and direct antiproton deceleration made possible. Because the H- and antiproton beams have the same charge but opposite direction, matching of the Recycler lattice to the Proton Driver is required to accommodate the reversed effect of the focusing and defocusing quadrupoles.  
FPAE026 Development of FFAG Accelerator at KEK acceleration, extraction, injection, septum 1943
  • Y. Yonemura, N. Ikeda, M. Matoba
    Kyushu University, Fukuoka
  • M. Aiba, S. Machida, Y. Mori, A. Muto, J. Nakano, C. Ohmori, K.O. Okabe, I. Sakai, Y. Sato, A. Takagi, T. Yokoi, M. Yoshii, Y. Yuasa
    KEK, Ibaraki
  • R. Taki
    GUAS/AS, Ibaraki
  • T. Uesugi
    NIRS, Chiba-shi
  • A. Yamazaki
    LNS, Sendai
  • M. Yoshimoto
    JAERI, Ibaraki-ken
  The 150MeV proton FFAG accelerator is constructed and a beam is extracted at the final energy. This is the prototype FFAG for various applications such as proton beam therapy. We are now in preparation for using an extracted beam in the practical applications.  
FPAE061 Status of the Booster Injector for the Duke FEL Storage Ring booster, vacuum, storage-ring, injection 3544
  • S. Mikhailov, M.D. Busch, M. Emamian, J.F. Faircloth, S.M. Hartman, J. Li, V. Popov, G. Swift, V. Vylet, P.W. Wallace, P. Wang, Y.K. Wu
    DU/FEL, Durham, North Carolina
  • O. Anchugov, N. Gavrilov, G.Y. Kurkin, Yu. Matveev, D. Shvedov, N. Vinokurov
    BINP SB RAS, Protvino, Moscow Region
  Funding: This work is supported by U.S. DOE grant # DE-FG02-01ER41175 and by AFOSR MFEL grant # F49620-001-0370.

This paper presents the current status of the booster synchrotron for the Duke FEL storage ring. The booster will provide full energy injection into the storage ring in a wide energy range from 0.27 to 1.2 GeV. When operating the Duke FEL storage ring as the High Intensity Gamma Source (HIGS) to produce gamma photons above 20 MeV with Compton scattering, continuous electron loss occurs. The top-off mode operation of the booster injector will enable the continuous operation of the HIGS facility by replenishing the lost electrons. The design requirement for a compact booster with the single bunch extraction capability remains a challenge for the machine development. Presently, the booster project is in the installation phase. The magnetic elements, vacuum chambers, injection and extraction kickers have been fabricated in the Budker Institute of Nuclear Physics, Russia. The diagnostic and control system is being developed in the FEL lab, Duke University. The commissioning of the booster synchrotron is planned for fall 2005.

FPAE063 Enhancements of Machine Reliability and Beam Quality in SPring-8 Linac for Top-Up Injection into Two Storage Rings linac, klystron, injection, feedback 3585
  • H. Hanaki, T. Asaka, H. Dewa, T. Kobayashi, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida
    JASRI/SPring-8, Hyogo
  SPring-8 has started its top-up operation from May 2004 in order to feed constant photon fluxes to users. The SPring-8 linac has been improved to realize stable and uninterrupted top-up injection into the SPring-8 storage ring and the NewSUBARU storage ring. The beam energy instability of 0.01% rms had been achieved by the following stabilization: RF amplitude and phase stabilization, synchronization of beam timing and linac's 2856 MHz RF and introduction of an energy compensation system (ECS). Feedback controls of steering magnets compensate long-term variation of beam trajectories at ends of beam transport lines. The presentation will include also recent improvements.  
FPAP003 Simulation Study of the Electron Cloud Instability in SuperKEKB electron, simulation, positron, vacuum 868
  • H. Fukuma
    KEK, Ibaraki
  • L. Wang
    BNL, Upton, Long Island, New York
  The electron-cloud instability (ECI), especially a beam blowup caused by the single-bunch instability, is one of the most important issues faced at existing B factories. In SuperKEKB which is an upgrade plan of the KEK B factory, a positron beam will be stored in the high energy ring after LINAC upgrade to mitigate the ECI and ante-chambers will be effective to reduce the number of electrons. Nevertheless the ECI might be an issue of SuperKEKB because a large beam current of 4.1A will be stored with a short bunch spacing of 2ns. We performed a simulation of the cloud buildup by a program CLOUDLAND. The average electron density and the electron density at the center of a chamber were calculated both in drift space and in various magnetic fields. The result shows that a solenoid field is very effective for reducing the electron density. The simulated electron density will be compared with a threshold electron density of the strong head-tail instability.  
FPAP013 Emittance Growth Caused by Electron Cloud Below the “Fast TMCI” Threshold: Numerical Noise or True Physics? electron, emittance, simulation, proton 1344
  • E. Benedetto, E. Benedetto
    Politecnico di Torino, Torino
  • G. Franchetti
    GSI, Darmstadt
  • K. Ohmi
    KEK, Ibaraki
  • D. Schulte, F. Zimmermann
    CERN, Geneva
  Simulations show a persisting slow emittance growth for electron cloud densities below the threshold of the fast Transverse Mode Coupling type instability, which could prove important for proton beams with negligible radiation damping, such as in the LHC. We report on a variety of studies performed to quantify the contributions to the simulated emittance growth from numerical noise in the PIC module and from an artificial resonance excitation due to the finite number of kicks per turn applied for modeling the cloud-bunch interaction.  
FPAT005 A Betatron Tune Fitting Package for the Tevatron 21.4 MHz Schottky betatron, antiproton, collider, pick-up 937
  • P. Lebrun, T. Sen, J. You, Z.Y. Yuan
    Fermilab, Batavia, Illinois
  • E. Todesco
    CERN, Geneva
  Accurate control of the Betatron tunes and chromaticities is required to optimize the dynamical aperture of any large synchrotron. The Fermilab Tevatron is equipped with two independent Schottky monitors, one operating at 21.4 MHz and the other 1.7 GHz. While the latter one allows us to characterize individual bunches separated by 396 ns, the former one has a larger Q and can give precise tune measurements. A new front-end and related data acquisition for this 21.4 MHz resonator has been installed and commissioned during the FY04 Collider RunII. Output signal are digitized at 100 KHz. Frequency spectra are transfered to dedicated server nodes and fitted in real time. Such frequency spectra are quite complex, due to inherent noise, horizontal/vertical coupling and synchrotron motion. Sophisticated fitting strategies are required. Optimization of this fitting package on relatively powerful commodity computer allows us to report tune and chromaticity measurements at almost 1 Hz. The architecture of the data acquisition system and this fitting package are described and results taken during the FY04 and FY05 runs are presented.  
FPAT055 The Radiation Safety Interlock System for Top-Up Mode Operation at NSRRC radiation, injection, booster, storage-ring 3328
  • C.R. Chen, F.D. Chang, S.-P. Kao, Joseph. Liu, R.J. Sheu, J.P. Wang
    NSRRC, Hsinchu
  The radiation safety interlock systems of NSRRC have been operated for more than a decade. Some modification actions have been implemented in the past to perfect the safe operation. The machine and its interlock system were originally designed to operate at the decay mode. Recently some improvement programs to make the machine injection from original decay mode to top-up mode at NSRRC has initiated. For users at experimental area the radiation dose resulted from top-up re-fill injections where safety shutters of beam-lines are opened will dominate. In addition to radiation safety action plans such as upgrading the shielding, enlarging the exclusion zones and improving the injection efficiency, the interlock system for top-up operation is the most important to make sure that injection efficiency is acceptable. To ensure the personnel radiation safety during the top-up mode, the safety interlock upgrade and action plans will be implemented. This paper will summarize the original design logic of the safety interlock system. Historical modification actions for this system will be mentioned. New design logic to ensure radiation safety for top-up mode operation will be discussed.  
FPAT071 Timing System for J-PARC linac, proton, power-supply, target 3853
  • F. Tamura
    JAERI/LINAC, Ibaraki-ken
  • J.C. Chiba, T. Katoh, M. Yoshii
    KEK, Ibaraki
  J-PARC has three accelerators running at the different repetition rates; a 400-MeV linac (50Hz), a 3-GeV rapid cycling synchrotron (RCS, 25Hz), and a 50-GeV synchrotron (MR). The linac and the RCS deliver the beam pluses to the different destinations in each cycle. The destinations are scheduled according to the machine operations. We define two kinds of timing, "scheduled timing" and "synchronization timing" so that the accelerators are operated with proper timing and the beam pulses are transported to the experimental facilities or the next accelerators. The J-PARC complex requires a stable and precise timing system. The system is based on a master clock generated by a synthesizer and the triggers are operated independently of the AC-line frequency. We describe the design of the J-PARC timing system and their configuration, and also present the hardware details.  
FPAT076 PC-LabView Based Control System in SAGA-LS linac, power-supply, vacuum, storage-ring 3976
  • H. Ohgaki
    Kyoto IAE, Kyoto
  • Y. Iwasaki, S. Koda, Y. Takabayashi, T. Tomimasu, K. Yoshida
    Saga Synchrotron Light Source, Industry Promotion Division, Saga City
  • H. Toyokawa
    AIST, Ibaraki
  A control system for SAGA Synchrotron Light Source (SAGA-LS) has been constructed. SAGA-LS is a small-medium size light source and is run by local government, which means there are a few number of staff in the laboratory. Thus the control system must be simple and robust, while inexpensive, easy to develop and maintain. The basic ideas of the system are 1) using PCs to build a low cost control system, 2) using off-shelf devices, FieldPoint (National Instrument) and PLCs, (FA-M3, Yokogawa), for robust and replaceable system, 3) using LabView for a quick in-house system development, 4) using channel access protocol between server and client to transparent from regular EPICS utilities, 5) using ActiveX CA to emulate the CA protocol. About 1,000 PVs are employed to control the magnet power supplies, the RF control sub-system, vacuum monitors, BPM data and several LCW data. The system has been operated and tuned at the beginning of the commissioning, spring 2004. MySQL database system also archives data to assist daily operation and to display the trend chart of the machine. The database applications developed by LabView, too.  
FPAT082 From Visualisation to Data Mining with Large Data Sets simulation, electron, proton, synchrotron-radiation 4114
  • A. Adelmann
    PSI, Villigen
  • R.D. Ryne, J.M. Shalf, C. Siegerist
    LBNL, Berkeley, California
  In 3D particle simulations, the generated 6D phase space data are can be very large due to the need for accurate statistics, sufficient noise attenuation in the field solver and tracking of many turns in ring machines or accelerators. There is a need for distributed applications that allow users to peruse these extremely large remotely located datasets with the same ease as locally downloaded data. This paper will show concepts and a prototype tool to extract useful physical information out of 6D raw phase space data. ParViT allows the user to project 6D data into 3D space by selecting which dimensions will be represented spatially and which dimensions are represented as particle attributes, and the construction of complex transfer functions for representing the particle attributes. It also allows management of time-series data. An HDF5-based parallel-I/O library, with C++, C and Fortran bindings simplifies the interface with a variety of codes. A number of hooks in ParVit will allow it to connect with a parallel back-end that is able to provide remote file access, progressive streaming, and even parallel rendering of particle sets in excess of 1Billion particles.  
FPAT090 ExperimentDesigner: A Tcl/Tk Interface for Creating Experiments in EPICS kicker, controls, monitoring, feedback 4245
  • H. Shang, M. Borland
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

ExperimentDesigner is a Tcl/Tk interface that allows users to easily design and run complicated experiments using a convenient graphical user interface (GUI). Features include: process variable monitoring, which pauses the experiment when values are out of range; user-defined initialization, execution, and finalization sequences; support of complex execution chains containing actions such as setting controls, reading values, running external programs, interacting with the user, etc.; collection of output data for convenient postprocessing; saving and loading of experiment configurations; convenient use of SDDS Toolkit programs; and execution of experiments from the command line without a GUI.

FOAA003 HOM Effects in Vacuum System with Short Bunches vacuum, resonance, positron, luminosity 289
  • A. Novokhatski
    SLAC, Menlo Park, California
  Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.

High luminosity in electron-positron factories requires high beam currents of very short bunches. SLAC PEP-II and KEKB B-factories are progressively increasing currents and gaining more and more luminosity. Because of this the interaction of high currents and vacuum chamber elements becomes more important for the operation of the rings. High Order Modes (HOM) excited by short intense bunches propagate along the vacuum chamber, penetrating and dissipating inside vital vacuum elements like shielded bellows, vacuum valves and vacuum pumps. As a result these elements can heat up or have temperature oscillations. Often HOM heating has a resonance character. HOM heating of vacuum pumps can lead to vacuum pressure increases. High frequency modes excited by short bunches “check” the quality of the vacuum chamber by detecting small gaps, weak RF screens or weak feed-through. At these high currents even smooth tapers and smooth collimators become a source of HOM production. We will discuss the physical nature of these very interesting HOM effects.

FOAD004 Laser Cooling of Relativistic Heavy Ion Beams ion, laser, electron, heavy-ion 401
  • U. Schramm, M.H. Bussmann, D. Habs
    LMU, München
  • K. Beckert, P. Beller, B.  Franzke, T. Kuehl, F. Nolden, M. Steck
    GSI, Darmstadt
  • S. Karpuk
    Johannes Gutenberg University Mainz, Mainz
  • S. Reinhardt, G. Saathoff
    MPI-K, Heidelberg
  Funding: Partially funded by the german BMBF (06ML183).

We report on the first laser cooling of a bunched beam of multiply charged C3+ ions performed at the ESR (GSI) at a beam energy of E=1.47GeV. Moderate bunching provided a force counteracting the decelerating laser force of one counterpropagating UV laser beam. This versatile type of laser cooling lead to longitudinally space-charge dominated beams with an unprecedented relative momentum spread of 10-7. Concerning the beam energy and charge state of the ion, the experiment depicts an important intermediate step from the established field of laser cooling of ion beams at low energies toward the laser cooling scheme proposed for relativistic beams of highly charged heavy ions at the future GSI facility FAIR.

FOPA003 Challenges and Progress in the FAIR Accelerator Project dipole, ion, antiproton, proton 294
  • P.J. Spiller
    GSI, Darmstadt
  An international "Facility for Antiproton and Ion Research (FAIR)" was proposed to be built at GSI, providing unique conditions for experiments involving heavy ion and antiprotons beams. The new accelerator complex consists of the fast ramped s.c. heavy ion synchrotrons, SIS100/300 and a storage ring system for experiments with radioactive ions and antiprotons. The two stage concept for SIS100/300 provides optimum conditions for the generation of beams with high intensities per cycle and in average, over a wide energy range and with various time structures. Bunch compression enables a matching to the production targets and storage rings. The storage ring complex was optimized for fast cooling and accumulation of the generated secondary beams. Unique conditions for internal target experiments with radioactive beams will be provided in NESR and for antiproton beams in the high energy storage ring HESR. The new accelerators require R&D work in various fields of technologies and beam physics, as e.g. operation with low charge state, high intensity, heavy ion beams in dynamic vacuum conditions, development of fast ramped s.c. magnets, powerful, low frequency rf systems, stochastic cooling systems and medium energy electron coolers.