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Paper Title Other Keywords Page
MOPA005 Protection Against Accidental Beam Losses at the LHC proton, monitoring, superconducting-magnet, dipole 492
  • J. Wenninger, R. Schmidt
    CERN, Geneva
  Protection of the LHC against uncontrolled beam losses is of prime importance due to the very high stored beam energy. For nominal beam intensities, each of the two 7 TeV/c proton beams has a stored energy of 350 MJ threatening to damage accelerator equipment. At injection a number of passive beam absorbers must be correctly positioned and specific procedures have been proposed to ensure safe injection of high intensity. The LHC beam dump block being the only LHC element that can safety absorb the full LHC beam, it is essential that the beams are extracted unto the dump block in case of emergency. The failure time constants extend from 100 microseconds to few seconds depending on the equipment. Failures must be detected at a sufficiently early stage and transmitted to the beam interlock system that triggers the beam dumping system. To ensure safe operation the machine protection system uses a variety of systems to detect such failures. The strategy for protection of the LHC will be illustrated, with emphasis on new developments and studies that aim for an increased redundancy of the protection system.  
MOPC004 Dynamics of a High Density Ion-Beam with Electron Cooling in HIMAC Synchrotron ion, injection, betatron, electron 416
  • T. Uesugi, T. Fujisawa, K. Noda, D. Tann
    NIRS, Chiba-shi
  • Y. Hashimoto
    KEK, Ibaraki
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  • S. Ninomiya
    RCNP, Osaka
  • S. Shibuya, H. Uchiyama
    AEC, Chiba
  High density circulating-ion beam was obtained with electron-cooling and cool-stacking injection in HIMAC synchrotron. The ion density was saturated at 1.0e9/cm2. Coherent transverse instability was observed when ion- and electron-beam density was high. The dynamics of the cooled ion-beam are described in this report.  
MOPC005 Chromaticity and Impedance Effect on the Transverse Motion of Longitudinal Bunch Slices in the Tevatron simulation, synchrotron, impedance, damping 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.

MPPE043 The Status of Optics Design and Beam Dynamics Study in J-PARC RCS injection, simulation, extraction, space-charge 2759
  • F. Noda, N. Hayashi, H. Hotchi, J. Kishiro, P.K. Saha, Y. Shobuda, K. Yamamoto
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Machida, A.Y. Molodojentsev
    KEK, Ibaraki
  The 3GeV RCS at J-PARC is designed to provide proton beam of 3GeV and a goal of output beam power is 1MW. The beam commissioning starts on May 2007. At present, more qualitative studies concerning beam dynamics are in progress: core beam handlings, halo beam handlings, instabilities and so on. In this paper, the RCS optics design and the present status of beam dynamics studies are summarized.  
MPPE048 Beam Based Alignment of the LHC Transfer Line Collimators alignment, injection, simulation, proton 3034
  • V. Kain, H. Burkhardt, B. Goddard, S. Redaelli
    CERN, Geneva
  At LHC injection energy the aperture available in the transfer lines and in the LHC is small and the intensities of the injected beams are an order of magnitude above the damage level. The setting of protection elements such as the transfer line collimators is therefore very critical; mechanical and optical tolerances must be taken into account to define the nominal setting. Being able to measure and control the collinearity of the collimator jaws with the beam relaxes the requirement on the settings considerably. A method to measure angular misalignment of the collimator jaws in the transfer line based on a transmission measurement is discussed. Simulations have been made and are compared with the results of an alignment test performed with beam during the 2004 commissioning of the transfer line TI 8.  
MPPP017 User Operation and Upgrades of the Fast Orbit Feedback at the SLS feedback, photon, insertion, damping 1538
  • M. Böge, B. Keil, A. Lüdeke, T. Schilcher
    PSI, Villigen
  A report on the performance of the fast orbit feedback (FOFB) in its 2nd year of user operation is given. Photon beam position monitors (XBPM) have been included by means of a slow feedback which changes the reference settings of the FOFB. Users are permitted to change the XBPM references within certain limits while the feedback is running. A fast synchronous readout of the XBPMs allows their integration into the FOFB loop. The FOFB will be extended by an additional beam position monitor (BPM) in order to satisfy the requirements of the upcoming FEMTO project.  
MPPP044 Impedance Calculation for Ferrite Inserts impedance, space-charge, resonance, vacuum 2818
  • S.-Y. Lee, S. Breitzmann
    IUCF, Bloomington, Indiana
  • K.Y. Ng
    Fermilab, Batavia, Illinois
  Funding: NSF PHY-0244793; DOE DE-FG02-92ER40747.

Passive ferrite inserts were used to compensate the space charge impedance in high intensity space charge dominated accelerators. We study the narrowband longitudinal impedance of these ferrite inserts. We find that the shunt impedance and the quality factor for ferrite inserts are inversely proportional to the imaginary part of the permeability of ferrite materials. We also provide a receipe for truly passive space charge impedance compensation and, at the same time, avoiding the narrowband microwave instabilities.

MPPT007 Design of the Pulse Bending Magnets for the Injection System of the 3-GeV RCS in J-PARC injection, power-supply, linac, extraction 1048
  • T. Takayanagi, Y. Irie, J. Kamiya
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • T. Kawakubo, I. Sakai
    KEK, Ibaraki
  The pulse bending magnets for the injection system of the 3-GeV RCS in J-PARC has been designed using a 3D magnetic analysis code. The injection system consists of the pulse bending magnets for the injection bump orbit, which are four horizontal bending magnets (shift bump), four horizontal painting magnets (h-paint bump), and two vertical painting magnets (v-paint bump). The injection beam energy and the extraction beam power are 400 MeV and 1 MW at 25-Hz repetition rate, respectively. The beam orbit area with a full acceptance beam of the injection beam, painting beam and the circulating beam at the shift bump points is a 400 mm width and a 250 mm height.The shift bump has accomplished 1.0% good field region at 0.22 T.  
TPAP004 Mechanical Design for Robustness of the LHC Collimators injection, proton, simulation, collimation 913
  • A. Bertarelli, O. Aberle, R.W. Assmann, S. Calatroni, A. Dallocchio, T. Kurtyka, M. Mayer, R. Perret, S. Redaelli, G. Robert-Demolaize
    CERN, Geneva
  The functional specification of the LHC Collimators requires, for the start-up of the machine and the initial luminosity runs (Phase 1), a collimation system with maximum robustness against abnormal beam operating conditions. The most severe cases to be considered in the mechanical design are the asynchronous beam dump at 7 TeV and the 450 GeV injection error. To ensure that the collimator jaws survive such accident scenarios, low-Z materials were chosen, driving the design towards Graphite or Carbon/Carbon composites. Furthermore, in-depth thermo-mechanical simulations, both static and dynamic, were necessary.This paper presents the results of the numerical analyses performed for the 450 GeV accident case, along with the experimental results of the tests conducted on a collimator prototype in Cern TT40 transfer line, impacted by a 450 GeV beam of 3.1·1013 protons, with impact parameters from 1 to 5 mm.  
TPAP006 Detecting Impacts of Proton Beams on the LHC Collimators with Vibration and Sound Measurements proton, radiation, collimation, acceleration 1018
  • S. Redaelli, O. Aberle, R.W. Assmann, A.M. Masi, G. Spiezia
    CERN, Geneva
  The 350 MJ stored energy of the 7 TeV LHC beams can seriously damage the beam line elements in case of accidental beam losses. Notably, the LHC collimators, which sit at 6 to 7 σs from the beam centre (1.2-1.4 mm), might be hit and possibly damaged in case of failures, with a consequent degradation of their cleaning performance. The experience from operating machines shows that an a-posteriori identification of the damaged collimators from the observed performance degradation is extremely challenging. Collimator tests with beam at the SPS have proven that the impact of 450 GeV proton beams at intensities from 1010 to 3x1013 can be detected by measuring the collimator vibrations. This was achieved by using high-resolution, radiation hard accelerometers and a microphone to record mechanical and sound vibrations of a LHC-like prototype collimator with impacting beams at different intensities and depth. A similar system could be also used in the LHC to detect collimators damaged by the beam.  
TPAP007 LHC Collimation: Design and Results from Prototyping and Beam Tests collimation, impedance, proton, insertion 1078
  • R.W. Assmann, O. Aberle, G. Arduini, A. Bertarelli, H.-H. Braun, M. Brugger, H. Burkhardt, S. Calatroni, F. Caspers, E. Chiaveri, A. Dallocchio, B. Dehning, A. Ferrari, M. Gasior, A. Grudiev, E.B. Holzer, J.-B. Jeanneret, J.M. Jimenez, Y. Kadi, R. Losito, M. Magistris, A.M. Masi, M. Mayer, E. Métral, R. Perret, C. Rathjen, S. Redaelli, G. Robert-Demolaize, S. Roesler, M. Santana-Leitner, D. Schulte, P. Sievers, E. Tsoulou, H. Vincke, V. Vlachoudis, J. Wenninger
    CERN, Geneva
  • I. Baishev, I.L. Kurochkin
    IHEP Protvino, Protvino, Moscow Region
  • G. Spiezia
    Naples University Federico II, Science and Technology Pole, Napoli
  The problem of collimation and beam cleaning concerns one of the most challenging aspects of the LHC project. A collimation system must be designed, built, installed and commissioned with parameters that extend the present state-of-the-art by 2-3 orders of magnitude. Problems include robustness, cleaning efficiency, impedance and operational aspects. A strong design effort has been performed at CERN over the last two years. The system design has now been finalized for the two cleaning insertions. The adopted phased approach is described and the expected collimation performance is discussed. In parallel robust and precisely controllable collimators have been designed. Several LHC prototype collimators have been built and tested with the highest beam intensities that are presently available at CERN. The successful beam tests are presented, including beam-based setup procedures, a 2 MJ robustness test and measurements of the collimator-induced impedance. Finally, an outlook is presented on the challenges that are ahead in the coming years.  
TPAP011 Reliability Assessment of the LHC Machine Protection System diagnostics, dumping, collider, hadron 1257
  • R. Filippini, B. Dehning, G. Guaglio, F. Rodriguez-Mateos, R. Schmidt, B. Todd, J.A. Uythoven, A. Vergara-Fernández, M. Zerlauth
    CERN, Geneva
  A large number of complex systems will be involved in ensuring a safe LHC operation, such as beam dumping and collimation, beam loss and position detection, quench protection, power interlock controller and beam interlock system. The latter will monitor the status of all other systems and trigger the beam abort if necessary. While the overall system is expected to provide an extremely high level of protection, none of the involved components should unduly impede machine operation by creating physically unfounded dump requests or beam inhibit signals. This paper investigates the resulting trade-off between safety and availability and provides quantitative results for the most critical protection elements.  
TPAP040 Feasibility Study of Beam-Beam Compensation in the Tevatron with Wires antiproton, injection, simulation, lattice 2645
  • T. Sen
    Fermilab, Batavia, Illinois
  • B. Erdélyi
    Northern Illinois University, DeKalb, Illinois
  Funding: Dept. of Energy.

At large distances the field profile of a current carrying wire matches the profile of the field of a round beam. We consider the practical applicability of this principle in compensating long-range beam-beam effects in the Tevatron. Changes in the helix and beam separation from injection energy to collision energy require that different wire configurations at these different energies. Due to the seventy or more long-range interactions, each set of wires must compensate several interactions. We first develop the principles of non-local compensation with a small set of wires. Next we use these principles in detailed simulation studies with beam-beam interactions and wire fields to determine the feasibility of the compensation in the Tevatron.

TPAT005 Start to End Error Study for the SPIRAL2 Linac linac, quadrupole, emittance, diagnostics 934
  • R. Duperrier, D. Uriot
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  Funding: CEA

The possibility of a high intensity accelerator at GANIL, producing secondary beams of unprecedented intensity, is considered. The proposed driver for the SPIRAL2 project aims to accelerate a 5 mA deuteron beam up to 20 A.MeV and a 1 mA ion beam for q/A = 1/3 up to 14.5 A.MeV. It is a continuous wave regime linac, designed for a maximum efficiency in the transmission of intense beams and a tunable energy. This paper presents the error sensitivity study which has been performed for this linac in order to define the tolerances for the construction. The correction scheme and the expected losses are described.

TPAT010 Practical Definitions of Beam Lifetimes in an Electron Storage Ring electron, polarization, scattering, storage-ring 1216
  • T.-Y. Lee
    PAL, Pohang, Kyungbuk
  Derived are simple definitions of beam lifetimes in an electron storage ring. They are defined in terms of measured beam lifetime and its time derivative. They are practical rather than theoretical. The only condition required is suppression or saturation of the radiative polarization.  
TPAT018 Stability of Barrier Buckets with Short or Zero Barrier Separations resonance, synchrotron, quadrupole, dipole 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.  
TPAT046 Nonlinear Stability of Intense Mismatched Beams in a Uniform Focusing Field focusing, space-charge, coupling, emittance 2941
  • R. Pakter, F.B. Rizzato, W. Simeoni
    IF-UFRGS, Porto Alegre
  Funding: Work supported by Brazilian agencies CNPq, CAPES, and FAPERGS.

We investigate the nonlinear coupling between axisymmetric and elliptic oscillations in the dynamics of intense beams propagating in a uniform magnetic focusing field. It is shown that finite amplitude mismatched oscillations of an initially round beam may destabilize elliptic oscillations, heavily affecting stability and the shape of the beam. This is a potential mechanics for beam particle loss in such systems. Self consistent simulations are performed to verify the findings.

TPAT070 Intensity and Bunch-Shape Dependent Beam Loss Simulation for the SIS100 resonance, ion, space-charge, lattice 3807
  • G. Franchetti, I. Hofmann, A. Orzhekovskaya, P.J. Spiller
    GSI, Darmstadt
  We have studied the combined influence of magnet nonlinearities, space charge and bunch shapes consistent with different RF scenarios on the long-term loss in the planned SIS100 synchrotron of the FAIR project. The simulation is a 3D tracking with "frozen-in" space charge calculation employing the MICROMAP code. Comparing a one-harmonic RF scenario with an alternative double-harmonic scenario we find that for the same absolute beam loss roughly twice the number of particles can be stored in the double-RF system. Moreover, a barrier bucket RF scenario is found to be loss free. This is due to the fact that loss is caused here by space-charge induced periodic resonance crossing, which is absent for the strictly flat bunch profile of the barrier case.  
TPAT081 Observation of Electron-Ion Effects at RHIC Transition electron, emittance, vacuum, octupole 4087
  • J. Wei, M. Bai, M. Blaskiewicz, P. Cameron, R. Connolly, A. Della Penna, W. Fischer, H. Huang, U. Iriso, R.C. Lee, R.J. Michnoff, V. Ptitsyn, T. Roser, T. Satogata, S. Tepikian, L. Wang, S.Y. Zhang
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

Electron cloud is found to be a serious obstacle on the upgrade path of the Relativistic Heavy Ion Collider (RHIC). At twice the design number of bunches, electron-ion interactions cause significant instability, emittance growth, and beam loss along with vacuum pressure rises when the beam is accelerated across the transition.

TPAT096 Focusing-Free Transition Crossing in RHIC using Induction Acceleration induction, acceleration, synchrotron, 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.

TOAD003 Development of the Beam Diagnostics System for the J-PARC Rapid-Cycling Synchrotron injection, proton, vacuum, linac 299
  • N. Hayashi, S.H. Hiroki, J. Kishiro, Y.T. Teruyama, R. Toyokawa
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • D.A. Arakawa, S. Lee, T. Miura, T. Toyama
    KEK, Ibaraki
  Development of the beam diagnostics system for the J-PARC (Japan Proton Accelerator Research Complex) Rapid-Cycling Synchrotron is described. The system consists of Beam Position Monitor (BPM), Beam Loss Monitor (BLM), Current monitors (DCCT, SCT, MCT, FCT, WCM), Tune meter system, 324MHz-BPM, Profile monitor, and Halo monitor. BPM electrode is electro-static type and its electronics is designed for both COD and turn-by-turn measurements. Five current monitors have different time constants in order to cover wide frequency range. The tune meter is consisted of RFKO and the beam pick-up electrode. For the continuous injected beam monitoring, 324MHz-BPM detects Linac frequency. Two types of profile monitor are multi-wire for low intensity tuning and the residual gas monitor for non-destructive measurement.  
TPPP007 Recent Progress at KEKB luminosity, vacuum, feedback, injection 1045
  • Y. Funakoshi, K. Akai, K. Ebihara, K. Egawa, A. Enomoto, J.W. Flanagan, H. Fukuma, K.  Furukawa, T. Furuya, J. Haba, S. Hiramatsu, T. Ieiri, N. Iida, H. Ikeda, T. Kageyama, S. Kamada, T. Kamitani, S. Kato, M. Kikuchi, E. Kikutani, H. Koiso, M. Masuzawa, T. Mimashi, A. Morita, T.T. Nakamura, H. Nakayama, Y. Ogawa, K. Ohmi, Y. Ohnishi, N. Ohuchi, K. Oide, M. Ono, M. Shimada, S. Stanic, M. Suetake, Y. Suetsugu, T. Sugimura, T. Suwada, M. Tawada, M. Tejima, M. Tobiyama, N. Tokuda, S. Uehara, S. Uno, N. Yamamoto, Y. Yamamoto, Y. Yano, K. Yokoyama, M. Yoshida, M. Yoshida, S.I. Yoshimoto
    KEK, Ibaraki
  • F. Zimmermann
    CERN, Geneva
  We summarize the machine operation of KEKB during past one year. Progress for this period, causes of present performance limitations and future prospects are described.  
TPPP039 Geant Simulation of Six-Dimensional Cooling of a Muon Beams in a Ring Coolers simulation, emittance, dipole, focusing 2580
  • A. Klier, G.G. Hanson
    UCR, Riverside, California
  The reduction of the phase-space volume of the beam (cooling) is essential for both muon colliders and neutrino factories. In a muon collider, in particular, the six-dimensional (6D) emittance must be reduced by six orders of magnitude. Cooling the beam in all phase space dimensions can be done through emittance exchange, where the beam loses energy passing through wedge-shaped absorbers in a dispersive magnetic field, designed in a way that fast muons go through more absorber material than slow ones and lose more energy. The longitudinal momentum is then regained using RF cavities. We simulate ring coolers, in which the beam undergoes 6-dimensional cooling through emittance exchange while rotating several times in the ring. The simulation software is a Geant3-based package, specially designed this purpose, with changing electric fields in RF cavities treated correctly. Magnetic fields are read from external maps. Some ring cooler designs and cooling simulation results are presented.  
TPPT020 30 GHz Power Production in CTF3 linac, vacuum, dipole, beam-loading 1695
  • W. Wuensch, C. Achard, H.-H. Braun, G. Carron, R. Corsini, A. Grudiev, S.T. Heikkinen, D. Schulte, J.P.H. Sladen, I. Syratchev, F. Tecker, I. Wilson
    CERN, Geneva
  One of the major objectives of CTF3 (CLIC Test Facility) is the production of 30 GHz power for the high-gradient testing of CLIC accelerating structures. To this end a dedicated beam line, power generating structure and power transfer line have been designed, installed and commissioned. 52 MW of 30 GHz power with a pulse length of 74 ns and a repetition rate of 16 Hz were delivered to the high-gradient test area. This will allow operation of test accelerating structures in the coming run of CTF3 up to the nominal CLIC accelerating gradient of 150 MV/m and beyond the nominal pulse length. The system is described and the performances of the CTF3 linac, beam line and the rf components are reviewed.  
WPAE012 Gamma-Ray Irradiation Experiments of Collimator Key Components for the 3GeV-RCS of J-PARC radiation, vacuum, proton, synchrotron 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.  
WPAE013 Development of the Collimator System for the 3GEV Rapid Cycling Synchrotron radiation, shielding, electron, vacuum 1365
  • K. Yamamoto
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • M. Kinsho
    Japan Atomic Energy Institute, Linac Laboratory, Tokai-Mura
  In order to localize the beam loss in the restricted area, the beam collimation system is prepared in the 3GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Complex (J-PARC) Project. The amount of the localized beam loss on the one collimator is estimated about 1.2kW, and that loss generates a large quantity of the secondary radiations. So the beam collimator must be designed that it is covered with enough shielding. We calculated the radiation level of the collimator and decided necessary shielding thickness. This result indicated that the residual dose rate at the outside surface of the shielding is mostly under 1mSv/h. We developed the remote cramp system and rad-hard components in order to reduce the radiation exposure during maintenance of the collimator. And also we coated Titanium Nitride (TiN) film on the inside surface of the vacuum chamber in order to reduce the secondary electron emission from the collimator and chamber surface. Now we investigate the possibility of another coating.  
WPAE028 Radiation Issues in the Fermilab Booster Magnets booster, proton, radiation, vacuum 2041
  • E. Prebys
    Fermilab, Batavia, Illinois
  Funding: Department of Energy.

The demands of the Fermilab neutrino program will require the 30 year old Fermilab 8 GeV Booster to deliver higher intensities than it ever has. Total proton throughput is limited by radiation damage and activation due to beam loss in the Booster tunnel. Of particular concern is the insulation in the 96 combined function lattice magnets. This poster describes a study of the potential radiation damage to these magnets from extended running at the planned intensities.

WPAE035 SNS Ring Injection Stripped Electron Collection: Design Analysis and Technical Issues electron, SNS, dipole, injection 2384
  • Y.Y. Lee, G.J. Mahler, W. Meng, D. Raparia, L. Wang, J. Wei
    BNL, Upton, Long Island, New York
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

This paper describes the simulation studies on the motions of stripped electrons generated in the injection section of the Spallation Neutron Source (SNS) accumulator ring and the effective collection mechanism. Such studies are important for high intensity machines, in order to reduce beam loss and protect other components in the vicinity. The magnetic field is applied to guide electrons to a collector, which is located at the bottom of the beam chamber. Part of the study results with and without considering the interactions between electrons and materials are presented and discussed. The final engineering design of the electron collector (catcher) is also presented and described.

WPAE042 Beam Loss and Residual Activation Trending survey, linac, SNS, focusing 2726
  • G.W. Dodson, M. Giannella, A.T. Ruffin, T.L. Williams
    ORNL, Oak Ridge, Tennessee
  Funding: This work was supported by SNS through UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The SNS Front End, Drift Tube Linac and most of the Coupled Cavity Linac have been operated during commissioning. Beam loss data were taken with differential Beam Current Monitors, and Beam loss Monitors during commissioning. Residual activation data were taken at various times during and after the run. An analysis of beam loss trending, beam loss monitor data and residual activation will be shown.

WPAE064 "Fast-Slow" Beam Chopping for Next Generation High Power Proton Drivers proton, linac, impedance, Spallation-Neutron-Source 3635
  • M.A. Clarke-Gayther
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  Funding: Work supported by CCLRC/RAL/ASTeC and by the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).

A description is given of two "state of the art" high voltage pulse generator systems, designed to address the requirements of a fast beam chopping scheme for next generation high power proton drivers.[1] Measurements of output waveform and timing stability, for fast transition short duration, and slower transition long duration pulse generators, are presented.

[1]M. A. Clarke-Gayther, "A Fast Beam Chopper for Next Generation High Power Proton Drivers," Proc. of the ninth European Particle Accelerator Conference (EPAC), Lucerne, Switzerland, 5-9 July, 2004, p. 1449-145.

WPAE070 Injector Power Supplies Reliability Improvements at the Advanced Photon Source power-supply, septum, booster, photon 3804
  • A.L. Hillman, S.J. Pasky, N. Sereno, R. Soliday, J. Wang
    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.

Operational goals for the APS facility include 97% availability and a mean time between unscheduled beam losses (faults) of 70 hours, with more than 5000 user hours of scheduled beam per year. To meet this objective, our focus has changed to maximizing the mean time between faults (MTBF). We have made various hardware and software improvements to better operate and monitor the injector power supply systems. These improvements have been challenging to design and implement in light of the facility operating requirements but are critical to maintaining maximum reliability and availability of beam for user operations. This paper presents actions taken as well as future plans to continue improving injector power supply hardware and software to meet APS user operation goals.

WPAT024 First Results from the Use of Dual Harmonic Acceleration on the ISIS Synchrotron synchrotron, acceleration, proton, 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.  
WPAT074 In Depth Diagnostics for RF System Operation in the PEP-II B Factory diagnostics, klystron, monitoring, feedback 3931
  • D. Van Winkle, J.D. Fox, D. Teytelman
    SLAC, Menlo Park, California
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

The PEP-II RF systems incorporate numerous feedback loops in the low-level processing for impedance control and operating point regulation. The interaction of the multiple loops with the beam is complicated, and the systems incorporate online diagnostic tools to configure the feedback loops as well as to record fault files in the case of an RF abort. Rapid and consistent analysis of the RF-related beam aborts and other failures is critical to the reliable operation of the B-Factory, especially at the recently achieved high beam currents. Procedures and algorithms used to extract diagnostic information from time domain fault files are presented and illustrated via example interpretations of PEP-II fault file data. Example faults presented will highlight the subtle interpretation required to determine to root cause. Some such examples are: abort kicker firing asynchronously, klystron and cavity arcs, beam loss leading to longitudinal instability, tuner read back jumps and poorly configured low-level RF feedback loop.

RPAP046 Real-Time Beam Loss Monitor Display Using FPGA Technology synchrotron, 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.  
RPAT005 Beam Diagnostics for the J-PARC Main Ring Synchrotron proton, electron, pick-up, target 958
  • T. Toyama, D.A. Arakawa, Y. Hashimoto, S. Lee, T. Miura, S. Muto
    KEK, Ibaraki
  • N. Hayashi, J. Kishiro, R. Toyokawa
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  Beam diagnostics: beam intensity monitors (DCCT, SCT, FCT, WCM), beam position monitors (ESM), beam loss monitors (proportional chamber, air ion chamber), beam profile monitors (secondary electron emission, gas-sheet) have been designed, tested, and will be installed for the Main Ring synchrotron of J-PARC (Japan Proton Accelerator Research Complex). This paper describes the basic design principle and specification of each monitor, with a stress on how to cope with high power beam (average circulation current of ~12 A) and low beam loss operation (less than 1 W/m except a collimator region). Some results of preliminary performance test using present beams and a radiation source will be reported.  
RPAT043 Developments of the Calibration Tools for Beam Position Monitor at J-PARC Linac linac, quadrupole, proton, beam-transport 2777
  • S. Sato, H. Akikawa, T. Tomisawa, A. Ueno
    JAERI/LINAC, Ibaraki-ken
  • Z. Igarashi, M. Ikegami, N. Kamikubota, S. Lee, T. Toyama
    KEK, Ibaraki
  In the J-PARC LINAC, there are mainly two requirements for the beam based calibration of beam position monitors (BPMs). One is that BPMs need to be calibrated with the accuracy of about a hundred micro-meters to minimize beam loss for the world highest class of proton intensity. The other is that about a hundred of BPMs need to be calibrated consistently. To achieve these requirements, the calibration tool are being developed with experiences on real beam in a MEBT line set for the DTL commissioning. Tools for simulating the beam trajectory using transport matrix (e.g. T3D) are being developed as well. The calibrated beam positions measured by BPMs are used in the simulation for tuning the beam. Implementation of the calibration tools on the same platform (e.g. SAD) with the simulation tools is important for higher usability during commissioning of whole J-PARC. In this paper, details of these developments around BPMs are to be reported.  
RPAT044 Segmented Foil SEM Grids at Fermilab target, booster, proton, instrumentation 2821
  • S.E. Kopp, D. Indurthy, Z. Pavlovich, M. Proga, R.M. Zwaska
    The University of Texas at Austin, Austin, Texas
  • B.B. Baller, S.C. Childress, R. Ford, D. Harris, C.L.K. Kendziora, C.D. Moore, G. R. Tassotto
    Fermilab, Batavia, Illinois
  Segmented Secondary Emission Monitors (SEM's) will be used to monitor the extracted 120 GeV proton beam for the NuMI facility at Fermilab. The SEM's are constructed from 5 micrometer thick Ti foils. The chambers have 10 cm beam aperture, and the foils are designed to result in 4·10-6 fractional beam loss when inserted in the beam. The foil strips have dynamic tensioning to withstand the heating from the 400kW proton beam. Results from prototype beam tests as well as from commissioning in the NuMI line will be presented.  
RPAT085 Initial Imaging of 7-GeV Electron Beams with OTR/ODR Techniques at APS radiation, dipole, booster, electron 4162
  • A.H. Lumpkin, W. Berg, N. Sereno, C. Yao
    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 development of nonintercepting (NI) diagnostics continues to be of interest at the Advanced Photon Source (APS) as well as elsewhere. In the three rings of the APS facility we use optical synchrotron radiation generated as the electron beam transits the dipole magnetic fields as an NI mechanism to image the beam during top-up operations. However, in the straight transport lines an alternative method is needed. Optical diffraction radiation (ODR) is under investigation to monitor 7-GeV beam trajectory and potentially transverse shape in the booster-to-storage ring (BTS) beamline during top-up operations. We have performed our initial measurements with an Al blade/mirror that served as an optical transition radiation (OTR) monitor when fully inserted into the beam and as an ODR monitor when the beam passed near the edge. In the case of ODR, appreciable signal is emitted by the metal when gamma times the reduced ODR wavelength is comparable to the impact parameter, where gamma is the Lorentz factor. Visible light optics and a standard CCD camera could thus be used for a few-mm impact parameter. We attribute the near-field signal for 1.5- to 3.0-mm impact parameters predominately to the ODR mechanism.

RPPE002 Installation and Radiation Maintenance Scenario for J-PARC 50 GeV Synchrotron radiation, vacuum, shielding, extraction 835
  • M. Yoshioka, H. Kobayashi, T. Oogoe, Y. Takeuchi, Y. Watanabe
    KEK, Ibaraki
  • Y. Kuniyasu
    MELCO SC, Tsukuba
  • H. Oki, Y. Takiyama
  Funding: Ministry of Education, Culture, Science and Technology, Japan

J-PARC comprises a 400 MeV linac (181 MeV at the first stage), a 3 GeV rapid-cycling synchrotron and a 50 GeV synchrotron (Main Ring), which will provide high power proton beam to the material and life science facility, the neutrino facility and the nuclear and particle physics experimental hall. The installation of the accelerator components for the Main Ring will be started on mid. 2005 and the beam commissioning is scheduled in end of 2007. This paper describes the installation scenario of the accelerator components into the main ring tunnel and the development of radiation maintenance scenario for the beam injection and ejection systems.

RPPE021 The SNS Machine Protection System: Early Commissioning Results and Future Plans SNS, diagnostics, injection, power-supply 1727
  • C. Sibley III, D.J. Armstrong, A. Jones, T.A. Justice, D.H. Thompson
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source under construction in Oak Ridge TN has commissioned low power beam up to 187 Mev. The number of MPS inputs is about 20% of the final number envisioned. Start-up problems, including noise and false trips, have largely been overcome by replacing copper with fiber and adding filters as required. Initial recovery time from Machine Protection System (MPS) trips was slow due to a hierarchy of latched inputs in the system: at the device level, at the MPS input layer, and at the operator interface level. By reprogramming the MPS FPGA such that all resets were at the input devices, MPS availability improved to acceptable levels. For early commissioning MPS inputs will be limited to beam line devices that will prohibit beam operation. For later operation, the number of MPS inputs will increase both software alarms and less intrusive MPS inputs such as steering magnets are implemented. Two upgrades to SNS are on the horizon: a 3 MW upgrade and a second target station. Although these are years away the MPS system as designed should easily accommodate the increase in power and pulse-to-pulse target switching at 120 Hz.

Work supported by the U.S. Department of Energy under contract DE-AC05-00OR22725.

RPPE026 Operating Experience with Meson Production Targets at TRIUMF target, proton, radiation, alignment 1919
  • E.W. Blackmore, A.S. Dowling, R. Ruegg, M.C. Stenning
    TRIUMF, Vancouver
  High power targets are now required for operation at beam powers in excess of 1 MW for spallation neutron sources and neutrino factories. TRIUMF has been operating beryllium and graphite meson production targets for many years. Although the proton beam power of 100 kW at 500 MeV is lower, the beam densities and fluences are higher than most operating solid targets as other accelerators use rotating targets or larger beam spots. The beam size on the TRIUMF targets is maintained at 0.15 cm2 and this beam density leads to proton fluences of 1·1023 protons/cm2 per year. The beryllium targets are rectangular rods immersed in a water-cooled stainless steel jacket. The pyrolytic graphite targets consist of pie-shaped segments bonded to a water-cooled copper saddle. Operating experience shows that the graphite targets suffer thermal damage above beam currents of 120 uA but will operate for long periods at 100 uA. The beryllium targets can operate to 200 uA and appear to survive radiation damage beyond 10 dpa although some targets have failed due to structural damage. This paper will describe the operating experience with these targets and present some thermal and radiation calculations.  
RPPE065 Beam Loss Ion Chamber System Upgrade for Experimental Halls ion, radiation, target, monitoring 3650
  • D.W. Dotson, D.J. Seidman
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by: U.S. DOE Contract No DE-AC05-84ER4015.

The Beam loss Ion Chamber System (BLICS) was developed to protect Jefferson Labs transport lines, targets and beam dumps from a catastrophic "burn through." Range changes and testing was accomplished manually requiring the experiment to be shut down. The new upgraded system is based around an "off the shelf" Programmable Logic Controller located in a single controll box supporting up to ten individual detectors. All functions that formerly required an entry into the experimental hall and manual adjustment can be accomplished from the Machine Control Center (MCC). A further innovation was the addition of a High Voltage "Brick" at the detector location. A single cable supplies the required voltage for the Brick and a return line for the ion chamber signal. The read back screens display range, trip point, and accumulated dose for each location. The new system is very cost effective and significantly reduces the amount of lost experimental time.

RPPE075 Injector Electronics for Multi-Turn Operation of the University of Maryland Electron Ring (UMER) dipole, injection, electron, cathode 3952
  • M. Holloway, T.F. Godlove, P.G. O'Shea, B. Quinn, M. Walter
    IREAP, College Park, Maryland
  • M. Reiser
    University Maryland, College Park, Maryland
  Funding: This work is funded by U.S. Department of Energy under grants DE-FG02-94ER40855 and DE-FG02-92ER54178.

Progress is described toward the development of pulse generators required for injection and extraction of the University of Maryland Electron Ring (UMER). The geometry, described elsewhere, employs a fast ironless dipole at the junction of a Y-shaped section of the ring. The dipole as developed has an inductance of 600 nH. The required +21 A, long pulse generator for multi-turn operation is installed. A pulser providing -42 A for deflection in the opposite sense during injection is under development. It must have a fall time of ~100 ns in view of the 200 ns circulation time for the beam. A similar pulser, having a 100 ns risetime is required for beam extraction. The fast pulsers employ MOSFET switches.

RPPP010 Considerations on the Design of the Decelerator of the CLIC Test Facility (CTF3) simulation, damping, linac, quadrupole 1177
  • D. Schulte, I. Syratchev
    CERN, Geneva
  Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).

One of the main aims of the CLIC Test Facility (CTF3) is to study the beam stability in the drive beam decelerator and to bench mark the performance against beam simulation codes. Particular challenges come from the large drive beam energy spread, the strong wakefields and potential beam losses. The development towards a decelerator design and the required instrumentation is described in this paper.

RPPP030 Design of ILC Extraction Line for 20 mrad Crossing Angle extraction, luminosity, diagnostics, optics 2134
  • Y. Nosochkov, K. C. Moffeit, A. Seryi, M. Woods
    SLAC, Menlo Park, California
  • R. Arnold
    University of Massachusetts, Amherst
  • W.P. Oliver
    Tufts University, Medford, Massachusetts
  • B. Parker
    BNL, Upton, Long Island, New York
  • E.T. Torrence
    University of Oregon, Eugene, Oregon
  Funding: Work supported by the Department of Energy Contract DE-AC02-76SF00515.

One of the two ILC Interaction Regions will have a large horizontal crossing angle which would allow to extract the spent beams in a separate beam line. In this paper, the extraction line design for 20 mrad crossing angle is presented. This beam line transports the primary e+/e- and beamstrahlung photon beams from the IP to a common dump, and includes diagnostic section for energy and polarization measurements. The optics is designed for a large energy acceptance to minimize losses in the low energy tail of the disrupted beam. The extraction optics, diagnostic instrumentation and particle tracking simulations are described.

RPPT065 Beam Loss Estimates and Control for the BNL Neutrino Facility injection, emittance, proton, linac 3647
  • W.-T. Weng, J. Beebe-Wang, Y.Y. Lee, D. Raparia, N. Tsoupas, J. Wei, S.Y. Zhang
    BNL, Upton, Long Island, New York
  Funding: This work is performed under the auspices of the US DOE.

BNL plans to upgrade the AGS proton beam from the current 0.14 MW to higher than 1.0 MW for a very long baseline neutrino oscillation experiment. This increase in beam power is mainly due to the faster repetition rate of the AGS by a new 1.5 GeV superconductiong linac as injector, replacing the existing booster. The requirement for low beam loss is very important both to protect the beam component, and to make the hands-on maintenance possible. In this report, the design considerations for achieving high intensity and low loss will be presented. We start by specifying the beam loss limit at every physical process followed by the proper design and parameters for realising the required goals. The process considered in this paper include the emittance growth in the linac, the H- injection, the transition crossing, the ecectron cloud effect, the coherent instabilities, and the extraction losses. Collimation and shielding are also presented.

ROPC004 Recent Intensity Increase in the CERN Accelerator Chain extraction, acceleration, injection, booster 413
  • E.N. Shaposhnikova, G. Arduini, T. Bohl, M. Chanel, R. Garoby, S. Hancock, K. Hanke, T.P.R. Linnecar, E. Métral, R.R. Steerenberg, B. Vandorpe
    CERN, Geneva
  Future requests for protons from the physics community at CERN, especially after the start-up of the CNGS experiments in 2006, can only be satisfied by a substantial increase in the SPS beam intensity per pulse. In September 2004 a three weeks beam run was dedicated to high intensity; all accelerators in the chain were pushed to their limits to study intensity restrictions and find possible solutions. New record intensities were obtained in the accelerators of the PS & SPS Complex with this fixed-target type beam which is different from the nominal LHC beam. The challenges in producing this high-intensity beam are described together with the measures needed to make it fully operational.  
ROPC006 Commissioning of Fermilab's Electron Cooling System for 8-GeV Antiprotons electron, antiproton, vacuum, simulation 540
  • S. Nagaitsev, D.R. Broemmelsiek, A.V. Burov, K. Carlson, C. Gattuso, M. Hu, B.J. Kramper, T.K. Kroc, J.R. Leibfritz, L.R. Prost, S.M. Pruss, G.W. Saewert, C.W. Schmidt, A.V. Shemyakin, M. Sutherland, V. Tupikov, A. Warner
    Fermilab, Batavia, Illinois
  • W. Gai
    ANL, Argonne, Illinois
  • G.M. Kazakevich
    BINP SB RAS, Novosibirsk
  • S. Seletsky
    Rochester University, Rochester, New York
  A 4.3-MeV electron cooling system has been installed at Fermilab in the Recycler antiproton storage ring and is being currently commissioned. The cooling system is designed to assist accumulation of 8.9-GeV/c antiprotons for the Tevatron collider operations. This paper will report on the progress of the electron beam commissioning effort as well as on detailed plans of demonstrating the cooling of antiprotons.  
FPAE019 Booster 6-GeV Study booster, acceleration, proton, linac 1637
  • X. Yang, C.M. Ankenbrandt, J.R. Lackey, R.D. Padilla, W. Pellico
    Fermilab, Batavia, Illinois
  • J. Norem
    ANL, Argonne, Illinois
  Funding: Fermi National Accelerator Laboratory, Accelerator Division, Proton Source Department.

Since a wider aperture has been obtained along the Fermilab Booster beam line, this opens the opportunity for Booster running a higher intensity proton beam than ever before. Sooner or later, the available RF accelerating voltage will become a new limit for the beam intensity. Either by increasing the RF accelerating voltage or by reducing the accelerating rate can achieve the similar goal. The motivation for the 6-GeV study is to gain the relative accelerating voltage via a slower acceleration.

FPAE024 Studies Performed in Preparation for the Spallation Neutron Source Accumulator Ring Commissioning injection, target, proton, multipole 1859
  • S.M. Cousineau, V.V. Danilov, S. Henderson, J.A. Holmes, M.A. Plum
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The Spallation Neutron Source accumulator ring will compress 1.5?1014, 1 GeV protons from a 1 ms bunch train to a single 695 ns proton bunch for use in neutron spallation. Due to the high beam power, unprecedented control of beam loss will be required in order to control radiation and allow for hands-on maintenance in most areas of the ring. A number of detailed investigations have been performed to understand the primary sources of beam loss and to predict and mitigate problems associated with radiation hot spots in the ring. The ORBIT particle tracking code is used to perform realistic simulations of the beam accumulation in the ring, including detailed modeling of the injection system, transport through the measured magnet fields including higher order multipoles, and beam loss and collimation. In this paper we present the results of a number of studies performed in preparation for the 2006 commissioning of the accumulator ring.

FPAE028 Design of the High Intensity Exotic Beams SPIRAL 2 Project linac, ion, rfq, quadrupole 2044
  • A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • M.H. Moscatello
    GANIL, Caen
  The SPIRAL 2 facility will be able to deliver stable heavy ion beams and deuteron beams at very high intensity, allowing to produce and accelerate light and heavy rare ion beams. The driver will accelerate a 5 mA deuteron beam up to 20 MeV/u and also q/A=1/3 heavy ions up to 14.5 MeV/u. The injector consist of the ion sources, a 4-vane RFQ and the low and medium beam transfer lines. It is followed by an independently phased superconducting linac with compact cryostats separated with warm focusing sections. The overall design and results of simulations with combined errors, the results of tests of prototypes for the most critical components are presented.  
FPAE047 Test Scheme Setup for the PEFP 20MeV DTL quadrupole, resonance, proton, klystron 2965
  • H.-S. Kim, Y.-S. Cho, Y.-H. Kim, H.-J. Kwon, K.T. Seol
    KAERI, Daejon
  • Y.-S. Hwang
    SNU, Seoul
  Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government.

A 100MeV proton accelerator is under development for the Proton Engineering Frontier Project (PEFP). The goal of the first stage of the project is to develop a 20MeV accelerator and the initial test of the 20MeV accelerator will be made. The DTL of 20 MeV accelerator consists of four tanks and will be driven with single klystron, which gives rise to some unique problems with regard to the way of independent resonance control for each tank. Some changes made in the LLRF for reducing phase or amplitude error of cavities affect all of four tanks simultaneously, for which it is not possible to use LLRF for individual control of phase and amplitude of each tank. For independent control of each tank, we are going to use the temperature control of the drift tubes as a frequency tuner. During the initial test of the DTL, the phase of each tank will be synchronized with the first tank phase, and beam based test will be performed as if all of tanks were single unit. The detailed description of the test scheme and the analysis results will be given in this paper.

FPAE056 Review of a Spoke-Cavity Design Option for the RIA Driver Linac linac, simulation, proton, acceleration 3360
  • P.N. Ostroumov, K.W. Shepard
    ANL, Argonne, Illinois
  • J.R. Delayen
    Jefferson Lab, Newport News, Virginia
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38.

A design option for the 1.4 GV, multiple-charge-state driver linac required for the U.S. Rare Isotope Accelerator Project based on 345 MHz, 3-cell spoke-loaded cavities has been previously discussed.* This paper updates consideration of design options for the RIA driver, including recent results from numerically-modeling the multi-charge-state beam dynamics and also cold test results for prototype superconducting niobium 3-cell spoke-loaded cavities.

*"High-energy ion linacs based on superconducting spoke cavities," K.W. Shepard, P.N. Ostroumov, and J.R. Delayen, Phys. Rev. ST Accel. Beams 6, 080101 (2003).

FPAE059 Transverse Matching Techniques for the SNS Linac linac, emittance, SNS, Spallation-Neutron-Source 3471
  • D.-O. Jeon, C. Chu, V.V. Danilov
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

It is crucial to minimize beam loss and machine activation by obtaining optimal transverse matching for a high-intensity linear accelerator such as the Spallation Neutron Source linac. For matching the Drift Tube Linac (DTL) to Coupled Cavity Linac (CCL), there are four wire-scanners installed in series in CCL module 1 as proposed by the author.* A series of measurements was conducted to minimize envelope breathing and the results are presented here. As an independent approach, Chu et al is developing an application based on another technique by estimating rms emittance using the wire scanner profile data.** For matching the Medium Energy Beam Transport Line to the DTL, a technique of minimizing rms emittance was used and emittance data show that tail is minimized as well.

*D. Jeon et al., "A technique to transversely match high intensity linac using only rms beam size from wire-scanners," Proceedings of LINAC2002 Conference, p. 88. **C. Chu et al., "Transverse beam matching application for SNS," in this conference proceedings.

FPAE067 Present Design and Calculation for the Injection-Dump Line of the RCS at J-PARC injection, quadrupole, emittance, linac 3739
  • P.K. Saha, N. Hayashi, H. Hotchi, Y. Irie, F. Noda, T. Takayanagi
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Machida, I. Sakai
    KEK, Ibaraki
  The RCS(rapid cycling synchrotron) of J-PARC(Japan proton accelerator research complex) acts as an injector to the main ring as well as a high-power beam for the spallation neutron source at a repetition rate of 25 Hz, where at present the injection and the extraction beam energy are chosen to be 0.181 GeV and 3.0 GeV, respectively. The present work concerns on the present design and calculations for the injection-dump line of the RCS, which includes, 1) an accurate aperture list of all elements taking into account a wide range of the betatron tune, effect of changing injection modes, multiple trajectories of different particles after the charge-exchange foil( like H0 from the H- and H- beam itself)and 2) an accurate estimation of the uncontrolled beam losses especially from the H0-excited states, multiple coulomb scattering at the charge-exchange foil and also the lorentz stripping loss at the septum magnets so as to optimize them concerning mainly the radiation issues as well as for the hands-on maintenance.  
FPAP024 Electron Cloud in the Collimator- and Injection- Region of the Spallation Neutron Source's Accumulator Ring electron, injection, SNS, simulation 1865
  • L. Wang, H.-C. Hseuh, Y.Y. Lee, D. Raparia, J. Wei
    BNL, Upton, Long Island, New York
  • S.M. Cousineau, S. Henderson
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The beam loss along the Spallation Neutron Source’s (SNS’s) accumulator ring is mainly located at the collimator region. From the ORBIT simulation, the peak power deposition at the three collimators is about 500, 350 and 240 W/m, respectively. Therefore, a sizeable number of electrons may be accumulated at this region due to the great beam loss. This paper simulated the electron cloud at the collimator region and the possible remedy.

FPAT014 Dynamic Visualization of SNS Diagnostics Summary Report and System Status SNS, diagnostics, emittance, target 1395
  • W. Blokland, D.J. Murphy, J.D. Purcell
    ORNL, Oak Ridge, Tennessee
  • A.V. Liyu
    RAS/INR, Moscow
  • C.D. Long
    Innovative Design, Knoxville, Tennessee
  • M. Sundaram
    University of Tennessee, Knoxville, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The Spallation Neutron Source (SNS) accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The SNS diagnostics platform is PC-based running Embedded Windows XP and LabVIEW. The diagnostics instruments communicate with the control system using the Channel Access (CA) protocol of the Experimental Physics and Industrial Control System (EPICS). This paper describes the Diagnostics Group’s approach to collecting data from the instruments, processing it, and presenting live in a summarized way over the web. Effectively, adding a supervisory level to the diagnostics instruments. One application of this data mining is the "Diagnostics Status Page" that summarizes the insert-able devices, transport efficiencies, and the mode of the accelerator in a compact webpage. The displays on the webpage change automatically to show the latest and/or most interesting instruments in use.

FPAT015 Beam Trajectory Correction for SNS SNS, dipole, linac, Spallation-Neutron-Source 1425
  • C. Chu, T.A. Pelaia
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

Automated beam trajectory correction with dipole correctors is developed and tested during the Spallation Neutron Source warm linac commissioning periods. The application is based on the XAL Java framework with newly developed optimization tools. Also, dipole corrector polarities and strengths, and beam position monitor (BPM) polarities were checked by an orbit difference program. The on-line model is used in both the trajectory correction and the orbit difference applications. Experimental data for both applications will be presented.

FPAT017 SNS Diagnostics Tools for Data Acquisition and Display diagnostics, SNS, target, scattering 1544
  • M. Sundaram
    University of Tennessee, Knoxville, Tennessee
  • W. Blokland
    ORNL, Oak Ridge, Tennessee
  • C.D. Long
    Innovative Design, Knoxville, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S Department of Energy.

The Spallation Neutron Source (SNS) accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of a 1.0 GeV linear accelerator, an accumulator ring and associated transport lines. The SNS diagnostics platform is PC-based and will run Windows for its OS and LabVIEW as its programming language. The diagnostics platform as well as other control systems and operator consoles use the Channel Access (CA) protocol of the Experimental Physics and Industrial Control System (EPICS) to communicate. This paper describes the tools created to evaluate the diagnostic instrument using our standard programming environment, LabVIEW. The tools are based on the LabVIEW Channel Access library and can run on Windows, Linux, and Mac OS X. The data-acquisition tool uses drop and drag to select process variables organized by instrument, accelerator component, or beam parameters. The data can be viewed on-line and logged to disk for later use. A drag and drop display creation tool supports the quick creation of graphical displays to visualize the data produced by the instruments without the need for programming.

FPAT026 The Dynamic Aperture of an Electrostatic Quadrupole Lattice simulation, lattice, quadrupole, focusing 1946
  • C.M. Celata, F.M. Bieniosek, P.A. Seidl
    LBNL, Berkeley, California
  • A. Friedman, D.P. Grote
    LLNL, Livermore, California
  • L.R. Prost
    Fermilab, Batavia, Illinois
  Funding: Work supported by the U.S. DOE, under contract numbers DE-AC03-76SF00098 and W-7405-Eng-48.

In heavy-ion-driven inertial fusion accelerator concepts, dynamic aperture is important to the cost of the accelerator, most especially for designs which envision multibeam linacs, where extra clearance for each beam greatly enlarges the transverse scale of the machine. In many designs the low-energy end of such an accelerator uses electrostatic quadrupole focusing. The dynamic aperture of such a lattice has been investigated for intense, space-charge-dominated ion beams using the 2-D transverse slice version of the 3-D particle-in-cell simulation code WARP. The representation of the focusing field used is a 3-D solution of the Laplace equation for the biased focusing elements, as opposed to previous calculations which used a less-accurate multipole approximation. 80% radial filling of the aperture is found to be possible. Results from the simulations, as well as corroborating data from the High Current Experiment at LBNL, will be presented.

FPAT030 Parametric Studies of Image-Charge Effects in Small-Aperture Alternating-Gradient Focusing Systems vacuum, simulation, focusing, quadrupole 2128
  • J.Z. Zhou, C. Chen
    MIT/PSFC, Cambridge, Massachusetts
  Funding: The U.S. Department of Energy, Office of High-Energy Physics, Grant No. DE-FG02-95ER40919, Office of Fusion Energy Science, Grant No. DE-FG02-01ER54662, and in part by Air Force Office of Scientific Research, Grant No. F49620-03-1-0230.

Image charges have important effects on an intense charged-particle beam propagating through an alternating-gradient (AG) focusing channel with a small circular aperture. This is especially true with regard to chaotic particle motion, halo formation, and beam loss.* In this paper, we examine the dependence of these effects on system parameters such as the filling factor of the AG focusing field, the vacuum phase advance, the beam perveance, and the ratio of the beam size to the aperture. We calculate the percentage of beam loss to the conductor wall as a function of propagating distance and aperture, and compare theoretical results with simulation results from the particle-in-cell (PIC) code PFB2D.

*Zhou, Qian and Chen, Phys. Plasmas 10, 4203 (2003).

FPAT047 Control System of 3 GeV Rapid Cycling Synchrotron at J-PARC simulation, linac, power-supply, monitoring 2968
  • H. Takahashi, Y. Kato, M. Kawase, H. Sako
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • Y. Ito
    Total Saport System Corp., Naka-gun, Ibaraki
  • H. Sakaki
    JAERI/LINAC, Ibaraki-ken
  • M. Sugimoto
    Mitsubishi Electric Control Software Corp, Kobe
  • H. Yoshikawa
    JAERI, Ibaraki-ken
  Funding: Japan Society for the Promotion of Science (JSPS).

Since the 3GeV RCS produces huge beam power of 1 MW, extreme cares must be taken to design the control system in order to minimize radiation due to beam loss. Another complexity appears in the control system, because each beam bunch of 25 Hz is required to be injected either into the MLF* or into the 50GeV MR.** Therefore, each bunch of 25 Hz must be operated separately, and the data acquisition system must collect synchronized data within each pulse. To achieve these goals, a control system via reflective memory and wave endless recorders has been developed. EPICS is adopted in the control system. Since the number of devices is huge, the management of EPICS records and their configurations require huge amount of time and man power. To reduce this work significantly, a RDB*** for static machine information has been developed. This RDB stores (1) EPICS related information of devices, interfaces, and IOC's**** with a capability to generate EPICS records automatically, and (2) machine geometrical information with a capability to generate lattice files for various simulation applications. The status of the control system focusing on the data acquisition system and the RDB will be presented.

*Material and Life Science Facility. **Main Ring. ***Relational Database. ****Input Output Controller.

FPAT061 CEBAF Distributed Data Acquisition System linac, klystron, electron, controls 3541
  • T.L. Allison, T. Powers
    Jefferson Lab, Newport News, Virginia
  Funding: This work was supported by DOE contract DE-AC05-84ER40150 Modification No. M175, under which the Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility.

There are thousands of signals distributed throughout Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF) that are useful for troubleshooting and identifying instabilities. Many of these signals are only available locally or monitored by systems with small bandwidths that cannot identify fast transients. The Distributed Data Acquisition (Dist DAQ) system will sample and record these signals simultaneously at rates up to 40 Msps. Its primary function will be to provide waveform records from signals throughout CEBAF to the Experimental Physics and Industrial Control System (EPICS). The waveforms will be collected after the occurrence of an event trigger. These triggers will be derived from signals such as periodic timers or accelerator faults. The waveform data can then be processed to quickly identify beam transport issues, thus reducing down time and increasing CEBAF performance. The Dist DAQ system will be comprised of multiple standalone chassis distributed throughout CEBAF. They will be interconnected via a fiber optic network to facilitate the global triggering of events. All of the chassis will also be connected directly to the CEBAF Ethernet and run EPICS locally. This allows for more flexibility than the typical configuration of a single board computer and other custom printed circuit boards (PCB) installed in a card cage.


FPAT088 Advanced Beam-Dynamics Simulation Tools for RIA linac, simulation, rfq, acceleration 4218
  • R.W. Garnett, J.A. Billen, T.P. Wangler
    LANL, Los Alamos, New Mexico
  • K.R. Crandall
    TechSource, Santa Fe, New Mexico
  • P.N. Ostroumov
    ANL, Argonne, Illinois
  • J. Qiang, R.D. Ryne
    LBNL, Berkeley, California
  • R.C. York, Q. Zhao
    NSCL, East Lansing, Michigan
  Funding: U.S. Department of Energy Contract W-7405-ENG-36.

We are developing multuparticle beam-dynamics simulation codes for RIA driver linac simulations extending from the low-energy beam transport line to the end of the linac. These codes run on the NERSC parallel supercomputing platforms at LBNL, which allow us to run simulations with large numbers of macroparticles. The codes have physics capabilities needed for RIA, including transport and acceleration of multiple-charge-state beams, beam-line elements such as high-voltage platforms within the linac, interdigital accelerating structures, charge-stripper foils, and capabilities for handling the effects of machine errors and other off-normal conditions. In this paper we present the status of the work, describe some recent additions to the codes, and show preliminary end-to-end simulation results for a representative driver-linac design.