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Paper Title Other Keywords Page
MOAA003 PEP-II and KEKB Operational Status luminosity, injection, interaction-region, beam-beam-effects 276
  • J. Seeman
    SLAC, Menlo Park, California
  Funding: Work supported by DOE contract DE-AC02-76SF00515.

The present two B-Factories, KEKB at Tsukuba in Japan and PEP-II at SLAC in California, operate at the Upsilon 4S and have reached parameter levels unprecedented for e+e- colliders. They have provided very large data samples for their respective particle detectors, BELLE and BaBar. Luminosities are approaching 1 x 1034/cm2/s and beyond. Beam currents have reached over 2.5 A with 1600 positron bunches spaced by 4 nsec. Continuous injection with the detectors taking data has added significantly to data collection rates. Bunch-by-bunch feedback systems damp strong longitudinal and transverse coupled bunch instabilities. The beam-beam interaction has allowed high tune shift levels even in the presence of parasitic crossing and crossing angle effects. Both B-Factory colliders have significant near term luminosity improvement programs.

MOAA005 FNAL Tevatron Operational Status antiproton, luminosity, proton, electron 484
  • D.P. McGinnis
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy.

The Fermilab Tevatron Proton-Antiproton Collider is currently the world’s highest energy hadron collider. The luminosity of the Fermilab collider has been significantly increased with the Main Injector operating at its design goals. Further increases in luminosity have been the result of combining antiprotons from the Recycler and Accumulator storage rings. Recent commissioning of proton slip-stacking in the Main Injector has noticeably increased the antiproton accumulation rate. The increased stacking rate permits the sustained operation of using antiprotons from both the Accumulator and Recycler. Further increases in peak luminosity are expected from electron cooling in the Recycler and increased antiproton flux from the Antiproton Source.

MOPA003 Testing of the LHC Magnets in Cryogenic Conditions: Operation Challenges, Status, and Outlook dipole, cryogenics, quadrupole, superconducting-magnet 250
  • V. Chohan
    CERN, Geneva
  For the Large Hadron Collider under construction at CERN and the testing of its 1706 lattice magnets in cryogenic conditions, considerable challenges had to be overcome since 2002 to arrive at the situation of today, with semi-routine operation of the purpose built tests facility. With the setting up of an Operation Team comprising of non-expert CERN Accelerator operation staff, few in number and a large external collaboration, it was essential to develop the methodology of working in light of external collaboration limits and base it on CERN-known techniques and experience in accelerator running-in, commissioning and routine operation. A flavour of the operation tools that were necessary or developed will be given, i.e., web-based tests follow-up management & information systems, development of precisely defined ‘to do list’ of tests sequences, associated methods, procedures and strict check-lists, electronic logbooks and so forth. The presentation will briefly outline the test programme and its context & constraints, give a summary of the accomplishments so far, together with the outlook for the successful completion of the whole programme within the project goals.  
MOPA010 Studies of the Chromaticity, Tune, and Coupling Drift in the Tevatron injection, dipole, coupling, sextupole 725
  • M.A. Martens, J. Annala, P. Bauer, V.D. Shiltsev, G. Velev
    Fermilab, Batavia, Illinois
  Chromaticity drift is a well-known and more or less well-understood phenomenon in superconducting colliders such as the Tevatron. Less known is the effect of tune and coupling drift, also observed in the Tevatron during injection. These effects are caused by field drifts in the superconducting magnets. Understanding of the behavior of the tune, coupling, and chromaticity at the start of the ramp is an important part of understanding the observed 5-10% loss in beam intensity at the start of the Tevatron ramp. In addition modifications in the Tevatron shot set-up procedure are being implemented to allow for a gain in integrated luminosity. In this context we conducted several beam-studies, during the period of April to August 2004, in which we measured the drift in the Tevatron chromaticity, tune and coupling during the injection porch. In some case we also measured the snapback at the start of the ramp. We will present the results of these studies data and put them into context of the results of off-line magnetic measurements conducted in spare Tevatron dipoles at the same time. Finally we will propose optimized feed-forward algorithms that successfully compensate for the drift effects in the Tevatron.  
MPPP007 Operating Performance of the Low Group Delay Woofer Channel in PEP-II feedback, damping, impedance, controls 1069
  • D. Teytelman, J.D. Fox, D. Van Winkle
    SLAC, Menlo Park, California
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

In PEP-II collider a dedicated low group-delay processing channel has been developed in order to provide high damping rates necessary to control the fast-growing longitudinal eigenmodes driven by the fundamental impedances of the RF cavities. A description of the digital processing channel operating at 9.81 MHz and capable of supporting finite impulse response (FIR) controllers with up to 32 taps will be presented. A prototype system has been successfully commissioned in the High-Energy Ring (HER) in May 2004. Operating experiences with the prototype and the newly determined limits on achievable longitudinal damping will be discussed and illustrated with experimental data.

MPPT029 Performance of an Adjustable Strength Permanent Magnet Quadrupole quadrupole, permanent-magnet, linear-collider, alignment 2071
  • S.C. Gottschalk, T.E. DeHart, K.W. Kangas
    STI, Washington
  • C.M. Spencer
    SLAC, Menlo Park, California
  • J.T. Volk
    Fermilab, Batavia, Illinois
  Funding: Department of Energy Grant DE-FG03-01ER83305.

An adjustable strength permanent magnet quadrupole suitable for use in Next Linear Collider has been built and tested. The pole length is 42cm, aperture diameter 13mm, peak pole tip strength 1.03Tesla and peak integrated gradient * length (GL) is 68.7 Tesla. This paper describes measurements of strength, magnetic centerline and field quality made using an air bearing rotating coil system. The magnetic centerline stability during -20% strength adjustment proposed for beam based alignment was < 0.2 microns. Strength hysteresis was negligible. Thermal expansion of quadrupole and measurement parts caused a repeatable and easily compensated change in the vertical magnetic centerline. Calibration procedures as well as centerline measurements made over a wider tuning range of 100% to 20% in strength useful for a wide range of applications will be described. The impact of eddy currents in the steel poles on the magnetic field during strength adjustments will be reported.

MPPT033 Development of a Superconducting Helical Undulator for a Polarised Positron Source undulator, positron, electron, linear-collider 2295
  • Y. Ivanyushenkov, F.S. Carr
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • D.P. Barber
    DESY, Hamburg
  • E. Baynham, T.W. Bradshaw, J. Rochford
    CCLRC/RAL, Chilton, Didcot, Oxon
  • J.A. Clarke, O.B. Malyshev, D.J. Scott, B.J.A. Shepherd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • P. Cooke, J.B. Dainton, T. Greenshaw
    Liverpool University, Science Faculty, Liverpool
  • G.A. Moortgat-Pick
    Durham University, Durham
  A method of producing a polarised positron beam from e+e- pair production in a target by circularly polarised ?-radiation is being investigated. Polarised photons are to be generated by the passage of a high energy electron beam (250 GeV as anticipated in the International Linear Collider - ILC) through a helical undulator. For production of 20 MeV photons, an undulator with a period of 14 mm, a bore of approximately 4 mm and magnetic field on axis of 0.75 T is required. First prototypes have been constructed using both superconducting and permanent magnet technologies which are capable of producing the necessary magnetic field configuration in the undulator. This paper details the design, construction techniques and field measurement results of the first superconducting prototype and compares the results with simulation.  
MPPT045 The Assembly of the LHC Short Straight Sections (SSS) at CERN: Project Status and Lessons Learned vacuum, background, quadrupole, instrumentation 2890
  • V. Parma, N. Bourcey, P.M. Dos Santos de Campos, R.C. Feitor, mg. Gandel, R. Lopez, M. Schmidlkofer, I. Slits
    CERN, Geneva
  The series production of the LHC SSS has started in the beginning of 2004 and is foreseen to last until end 2006. The production consists in the assembly of 474 cold masses housing superconducting quadrupoles and corrector magnets within their cryostats. 87 cold mass variants, resulting from various combinations of main quadrupole and corrector magnets, have to be assembled in 55 cryostat types, depending on the specific cryogenic and electrical powering schemes required by the collider topology. The assembly activity features the execution of more than 5 km of leak-tight welding on 20-bar design pressure cryogenic lines in stainless steel and aluminium, according to high qualification standards and undergoing severe QA inspections. Some 2500 leak detection tests, using He mass spectrometry, are required to check the tightness of the cryogenic circuits. Extensive electrical control work, to check the integrity of the magnet instrumentation and electrical circuits throughout the assembly of the SSS, is also carried out. This paper presents the current status of production, the assembly facilities at CERN, work organisation and Quality Assurance issues, and the acquired assembly experience after one and a half years of production.  
TPAE039 The Effects of Ion Motion in Very Intense Beam-Driven Plasma Wakefield Accelerators ion, plasma, emittance, electron 2562
  • J.B. Rosenzweig, A.M. Cook, M.C. Thompson, R.B. Yoder
    UCLA, Los Angeles, California
  Funding: This work is supported by U.S. Dept. of Energy grant DE-FG03-92ER40693.

Recent proposals for using plasma wakefield accelerators in the blowout regime as a component of a linear collider have included very intense driver and accelerating beams, which have densities many times in excess of the ambient plasma density. The electric fields of these beams are widely known to be large enough to completely expel plasma electrons from the beam path; the expelled electrons often attain relativistic velocities in the process. We examine here another aspect of this high-beam density scenario: the motion of ions. In the lowest order analysis, for both cylindrically symmetric and "flat" beams, it is seen that for the recently discussed "after-burner" scenario the ions completely collapse inside of the electron beam. In this case the ion density is significantly increased, with a large increase in the beam emittance expected as a result. Particle-in-cell simulations of ion-collapse in the nonlinear regime are discussed.

TPAE041 Modeling TeV Class Plasma Afterburners simulation, plasma, acceleration, emittance 2666
  • C. Huang, C.E. Clayton, 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
    SLAC, Menlo Park, California
  • S. Deng, T.C. Katsouleas, P. Muggli, E. Oz
    USC, Los Angeles, California
  Funding: Work supported by DOE and NSF.

Plasma wakefield acceleration can sustain acceleration gradients three orders of magnitude larger than conventional RF accelerator. In the recent E164X experiment, substantial energy gain of about 3Gev has been observed. Thus, a plasma afterburner, which has been proposed to double the incoming beam energy for a future linear collider, is now of great interest. In an afterburner, a particle beam drives a plasma wave and generates a strong wakefield which has a phase velocity equal to the velocity of the beam. This wakefield can then be used to accelerate part of the drive beam or a trailing beam. Several issues such as the efficient transfer of energy and the stable propagation of both the drive and trailing beams in the plasma are critical to the afterburner concept. We investigate the nonlinear beam-plasma interaction in such scenario using the 3D computer modeling code QuickPIC. We will report the latest simulation results of both 50 GeV and 1 TeV plasma afterburner stages for electrons including the beam-loading of a trailing beam. Analytic analysis of hosing instability in this regime will be presented.

TPAP002 Summary of Recent Studies of Cryosorbers for LHC Long Straight Sections vacuum, injection, hadron, electron 791
  • R.V. Dostovalov, V.V. Anashin, A.A. Krasnov
    BINP SB RAS, Novosibirsk
  Funding: This work was supported by CERN AT Division vacuum group.

The vacuum chamber inside some cryogenic elements in the LHC long straight sections will have cold bore (CB) at 4.5K and a beam screen (BS) at temperature between 5 and 20K. The gas molecules desorbed due to photons and electrons will pass through the slots on the BS to the shadowed part between the CB and BS. All desorbed gases except H2 could be adsorbed on the CB and BS but a cryosorber is required to pump H2. The new types of anodized aluminum, porous copper and charcoal-based materials were developed and studied to cryopump H2 at temperatures between 10 and 20K. The advantages and disadvantages of cryosorbers and technological problems of development of new similar cryosorbers were defined. The vacuum parameters of LHC vacuum chamber prototypes with charcoal and two types of carbon fiber cryosorbers were measured. The dynamic pressure behavior at BS temperature oscillations was studied for BS with woven carbon fiber to predict the dynamic pressure at nonstandard or transient regimes of the LHC operation. A main result is that woven carbon fiber cryosorber meets the LHC requirements and can be proposed as cryosorber for LHC. The summary results of these studies are presented.

TPAP010 Reliability Analysis of the LHC Beam Dumping System diagnostics, dumping, extraction, kicker 1201
  • R. Filippini, E. Carlier, L. Ducimetière, B. Goddard, J.A. Uythoven
    CERN, Geneva
  The design of the LHC Beam Dumping System is aimed at ensuring a safe beam extraction and deposition under all circumstances. The system adopts redundancy and continuous surveillance for most of its parts. Extensive diagnostics after each beam dumping action will be performed to reduce the risk of a faulty operation at the subsequent dump trigger. Calculations of the system’s safety and availability are presented, considering the detailed design of the trigger generation system and the power converters of the beam dumping kickers and septa magnets.  
TPAP011 Reliability Assessment of the LHC Machine Protection System beam-losses, diagnostics, dumping, 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.  
TPAP021 A New Technique for Making Bright Proton Bunches using Barrier RF Systems proton, emittance, simulation, luminosity 1745
  • C.M. Bhat
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Association, Inc., under contract DE-AC02-76CH03000 with the U.S. Department of Energy.

I describe here very promising schemes for producing high intensity low longitudinal emittance proton bunches for pp and ppbar high energy colliders. These methods are based on the use of wide-band barrier rf systems in the up-stream circular accelerators. The beam dynamics simulations clearly suggest that these schemes allow a wide range of bunch intensities and longitudinal emittances. In this paper I present the principle of these methods and results of multi-particle beam dynamics simulations applied to the Fermilab Tevatron. The feasibility of these methods to LHC pp collider will also be discussed. I also review a few other schemes which have been adopted and investigated at collider facilities.

TPAP022 Mixed pbar Source Operation at the Fermilab Tevatron injection, acceleration, luminosity, simulation 1763
  • C.M. Bhat, D. Capista, B. Chase, J.E. Dey, I. Kourbanis, K. Seiya, V. Wu
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Association, Inc., under contract DE-AC02-76CH03000 with the U.S. Department of Energy.

Recently, we have adopted a scheme called "Mixed pbar Source Operation" to transfer 2.5 MHz pbar bunches from the Recycler and the Accumulator to the Fermilab Main Injector (MI). In this scheme, 2.5MHz pbar bunches are captured adiabatically in 53 MHz buckets at 8 GeV in the MI and accelerated to 150 GeV before bunch coalescing and transfer to the Tevatron collider stores. A special magnet ramp was needed in the MI to allow for pbar beam of slightly different 8 GeV energies from the Recycler and the Accumulator. Here we present the details of the scheme and its advantage over the method used for past several years.

TPAP028 Observations of Strong Transverse Coupling in the Tevatron quadrupole, coupling, dipole, betatron 2029
  • M.J. Syphers, G. Annala, D.A. Edwards, N.M. Gelfand, J.A. Johnstone, M.A. Martens, T. Sen
    Fermilab, Batavia, Illinois
  Funding: United States Department of Energy under Contract No. DE-AC02-76CH03000.

During the beginning of Run II of the Tevatron Collider it became apparent that a large skew quadrupole source, or sources, had developed in the superconducting synchrotron. Efforts to locate the current source of coupling were undertaken, with the eventual discovery that the main magnets had developed a systematic skew quadrupole moment over their lifetime. Over the past year, the magnets have been altered in place in an attempt to restore the systematic skew quadrupole moment to zero. Beam observations and their interpretations are presented, and remedial measures are discussed.

TPAP052 Possible Phase Loop for the Global Decoupling coupling, quadrupole, feedback, simulation 3182
  • Y. Luo, P. Cameron, A. Della Penna, A. Marusic, S. Peggs, T. Roser, D. Trbojevic
    BNL, Upton, Long Island, New York
  • O.R. Jones
    CERN, Geneva
  Funding: Work supported by U.S. DOE under contract No. DE-AC02-98CH10886.

Besides two eigentunes Q1 and Q2 , two amplitude ratios r1 and r2 and two phase differences ∆ φ1 and ∆ φ2 are introduced for the global coupling observation. Simulations are carried out to check their behaviors in the process of the skew quadrupole strength scans. Some attractive features of the phase differences ∆ φ1,2 have been found, which are possibly useful for the global decoupling phase loop, or future global decoupling feedback. Analytical descriptions to these 6 quantities are described in the Twiss parameters through the linear coupling's action-angle parameterization, or in coupling coefficient through the linear coupling's Hamiltonian perturbation theory. Dedicated beam experiments are carried out at the Relativistic Heavy Ion Collider (RHIC) to check the global coupling observables from the phase lock loop (PLL) system. The six observables are measured under PLL driving oscillations during the 1-D and 2-D skew quadrupole scans. The experimental results are reported and discussions are given.

TPAT076 Measurement of the Luminous-Region Profile at the PEP-II IP, and Application to e± Bunch-Length Determination luminosity, monitoring, simulation, optics 3973
  • B.F. Viaud
    Montreal University, Montreal, Quebec
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • I.V. Narsky
    CALTECH, Pasadena, California
  • C. O'Grady, A. Perazzo
    SLAC, Menlo Park, California
  The three-dimensional luminosity distribution at the interaction point (IP) of the SLAC B-Factory is measured continuously, using e+e- –> e+e- and e+e –> mu+mu- events reconstructed online in the silicon tracker of the BaBar detector. The centroid of the transverse luminosity profile provides a very precise and reliable monitor of medium- and long-term orbit drifts at the IP. The longitudinal centroid is sensitive to variations in the relative RF phase of the colliding beams, both over time and differentially along the bunch train. The measured horizontal r.m.s. width of the distribution is consistent with a sizeable dynamic-beta effect; it is also useful as a benchmark of strong-strong beam-beam simulations. The longitudinal luminosity distribution depends on the e± bunch lengths and vertical IP beta-functions, which can be different in the high- and low-energy rings. Using independent estimates of the beta-functions, we analyze the longitudinal shape of the luminosity distribution in the presence of controlled variations in accelerating RF voltage and/or beam current, to extract separate measurements of the e+ and e- bunch lengths.  
TPAT077 Beam-Beam Study on the Upgrade of Beijing Electron Positron Collider luminosity, simulation, injection, positron 4000
  • S. Wang
    IHEP Beijing, Beijing
  • Y. Cai
    SLAC, Menlo Park, California
  It is an important issue to study the beam-beam interaction in the design and performance of such a high luminosity collider as BEPCII, the upgrade of Beijing Electron Positron Collider. The weak-strong simulation is generally used during the design of a collider. For performance a large scale tune scan, the weak-strong simulation studies on beam-beam interaction were done, and the geometry effects were taken into account The strong-strong simulation studies were done for investigating the luminosity goal and the dependence of the luminosity on the beam parameters.  
TPAT093 Operations and Performance of RHIC as a Cu-Cu Collider luminosity, ion, emittance, background 4281
  • F.C. Pilat, L. Ahrens, M. Bai, D.S. Barton, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, D. Bruno, P. Cameron, R. Connolly, T. D'Ottavio, J. DeLong, K.A. Drees, W. Fischer, G. Ganetis, C.J. Gardner, J. Glenn, M. Harvey, T. Hayes, H.-C. Hseuh, H. Huang, P. Ingrassia, U. Iriso, R.C. Lee, V. Litvinenko, Y. Luo, W.W. MacKay, G.J. Marr, A. Marusic, R.J. Michnoff, C. Montag, J. Morris, T. Nicoletti, B. Oerter, V. Ptitsyn, T. Roser, T. Russo, J. Sandberg, T. Satogata, C. Schultheiss, S. Tepikian, R. Tomas, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, K. Vetter, A. Zaltsman, K. Zeno, S.Y. Zhang, W. Zhang
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons at 100 GeV. We will address here overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a ?* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements and machine performance limitations, such as vacuum pressure rise, intra-beam scattering, and beam beam interaction.

TPAT097 CLIC Drive Beam and LHC Based FEL-Nucleus Collider photon, electron, linac, ion 4320
  • O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  • H.-H. Braun, R. Corsini
    CERN, Geneva
  • S. Sultansoy
    Gazi University, Faculty of Science and Arts, Ankara
  Funding: Ankara University, Ankara, TURKEY.

Main parameters of CLIC-LHC based FEL-Nucleus collider are determined. The matching of beam structures for maximum luminosity is studied. The advantages of the collider with respect to the traditional Nuclear Resonance Fluorescence (NRF) methods are presented considering (/Gamma-/Gamma(prime)) reactions. Determination of unknown decay width, spin and parity of excited levels is discussed for Pb nucleus.

TPAT098 A Review of TeV Scale Lepton-Hadron and Photon-Hadron Colliders luminosity, lepton, linac, hadron 4329
  • S. Sultansoy
    Gazi University, Faculty of Science and Arts, Ankara
  Funding: Gazi University, Ankara, Turkey.

The investigation of lepton-hadron and photon-hadron collisions at TeV scale is crucial both to clarify the strong interaction dynamics from nuclei to quark-parton level and for adequate interpretation of experimental data from future hadron colliders (LHC and VLHC). In this presentation different TeV scale lepton-hadron and photon-hadron collider proposals (such as THERA, "LEP"-LHC, QCD Explorer etc) are discussed. The advantages of linac-ring type colliders has been shown comparatively.

TPAT099 Main Parameters of ILC-Tevatron Based Lepton-Hadron and Photon-Hadron Colliders electron, luminosity, photon, proton 4335
  • S. Sultansoy
    Gazi University, Faculty of Science and Arts, Ankara
  • O. Cakir, A.K. Ciftci
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  • E. Recepoglu
    Turkish Atomic Energy Authority, Ankara
  • O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  Funding: Ankara University.

The construction of the ILC tangential to Tevatron ring will give opportunity to investigate electron-proton, positron-proton, electron-antiproton, positron-antiproton interactions at 1 TeV center of mass energy. The analysis of the lepton-hadron collisions in these energy region is very important both for understanding of strong interaction dynamics and for adequate interpretation of future LHC and VLHC data. In addition, ILC-Tevatron collider will provide a possibility to realize photon-hadron collisions in the same energy region using Compton backscattered laser photon of ILC electron beam. Main parameters of these colliders are estimated and their physics search potential is briefly discussed.

TPPE038 Thermal Hydraulic Design of PWT Accelerating Structures electron, feedback, linear-collider, simulation 2524
  • D. Yu, A. Baxter, P. Chen, M. Lundquist, Y. Luo
    DULY Research Inc., Rancho Palos Verdes, California
  Funding: Work supported by DOE SBIR Grant No. DE-FG02-03ER83846.

Microwave power losses on the surfaces of accelerating structures will transform to heat which will deform the structures if it is not removed in time. Thermal hydraulic design of the disk and cooling rods of a Plane Wave Transformer (PWT) structure is presented. Experiments to measure the hydraulic (pressure vs flow rate) and cooling (heat removed vs flow rate) properties of the PWT disk are performed, and results compared with simulations using Mathcad models and the COSMOSM code. Both experimental and simulation results showed that the heat deposited on the structure could be removed effectively using specially designed water-cooling circuits and the temperature of the structure could be controlled within the range required.

TPPP010 Photon-Nucleon Collider Based on LHC and CLIC luminosity, electron, proton, photon 1207
  • H. Aksakal, A.K. Ciftci
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  • D. Schulte, F. Zimmermann
    CERN, Geneva
  We describe the scheme of a photon-nucleon collider where high-energy photons generated by Compton back-scattering off a CLIC electron beam, at either 75 GeV or 1.5 TeV, are collided with protons or ions stored in the LHC. Different design constraints for such a collider are discussed and the achievable luminosity performance is estimated.  
TPPP015 ELIC at CEBAF electron, ion, luminosity, emittance 1437
  • Y.S. Derbenev, S.A. Bogacz, J.R. Delayen, J.M. Grames, A. Hutton, G.A. Krafft, R. Li, L. Merminga, M. Poelker, B.C. Yunn, Y. Zhang
    Jefferson Lab, Newport News, Virginia
  • C. Montag
    BNL, Upton, Long Island, New York
  Funding: Work supported by DOE Contract DE-AC05-84ER40150.

We report on the progress of the conceptual development of the energy recovering linac (ERL)-based Electron-Light Ion Collider (ELIC) at CEBAF that is envisioned to reach luminosity level of 1033-1035 /cm2s with both beams polarized to perform a new class of experiments in fundamental nuclear physics. Four interaction points with all light ion species longitudinally or transversally polarized and fast flipping of the spin for all beams are planned. The unusually high luminosity concept is based on the use of the ERL and circulator ring-based electron cooling and crab crossing colliding beams. Our recent studies concentrate on the design of low beta interaction points with crab-crossing colliding beams, the exploration on raising the polarized electron injector current to the level of 3-30 mA with the use of electron circulator-collider ring, forming a concept of stacking and cooling of the ion beams, specifications of the electron cooling facility, and studies of beam-beam interaction and intra-beam scattering.

TPPP034 Parameters of a Super-B-Factory Design luminosity, interaction-region, factory, linac 2333
  • J. Seeman, Y. Cai, S. Ecklund, J.D. Fox, S.A. Heifets, N. Li, P.A. McIntosh, A. Novokhatski, M.K. Sullivan, D. Teytelman, U. Wienands
    SLAC, Menlo Park, California
  • M.E. Biagini
    INFN/LNF, Frascati (Roma)
  Funding: Work supported by DOE contract DE-AC02-76SF00515.

Submitted for the High Luminosity Study Group: Parameters are being studied for a high luminosity e+e- collider operating at the Upsilon 4S that would deliver a luminosity in the range of 7 to 10 x 1035/cm2/s. Particle physics studies dictate that a much higher luminosity collider is needed to answer new key physics questions. A Super-B-Factory with 20 to 100 times the performance of the present PEP-II accelerator would incorporate a higher frequency RF system, lower impedance vacuum chambers, higher power synchrotron radiation absorbers, and stronger bunch-by-bunch feedback systems. Parameter optimizations are discussed.

TPPP040 Front-End Design Studies for a Muon Collider target, simulation, proton, dipole 2610
  • R.C. Fernow, J.C. Gallardo
    BNL, Upton, Long Island, New York
  Funding: Work supported by U.S. Department of Energy.

Using muons instead of electrons is a promising approach to designing a lepton-lepton collider with energies beyond that available at the proposed ILC. At this time a self-consistent design of a high-luminosity muon collider has not been completed. However, a lot of progress has been made in simulating cooling and parts of other systems that could play a role in an eventual collider design. In this paper we look at front-end system designs that begin with a single pion bunch produced from a high power mercury target. We present ICOOL simulation results for phase rotation, charge separation, and pre-cooling of the muon beams. A design is presented for a single-frequency phase rotation system that can transmit 0.47 muons per incident proton on the target. A bent solenoid can be used for high-efficiency separation of the positive and negative muon beams.

TPPP043 ERL Based Electron-Ion Collider eRHIC electron, proton, luminosity, ion 2768
  • V. Litvinenko, L. Ahrens, M. Bai, J. Beebe-Wang, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, R. Calaga, X.Y. Chang, A.V. Fedotov, W. Fischer, D. Kayran, J. Kewisch, W.W. MacKay, C. Montag, B. Parker, S. Peggs, V. Ptitsyn, T. Roser, A. Ruggiero, T. Satogata, B. Surrow, S. Tepikian, D. Trbojevic, V. Yakimenko, S.Y. Zhang
    BNL, Upton, Long Island, New York
  • A. Deshpande
    Stony Brook University, Stony Brook
  • M. Farkhondeh
    MIT, Middleton, Massachusetts
  Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy.

We present the designs of a future polarized electron-hadron collider, eRHIC* based on a high current super-conducting energy-recovery linac (ERL) with energy of electrons up to 20 GeV. We plan to operate eRHIC in both dedicated (electron-hadrons only) and parallel(with the main hadron-hadron collisions) modes. The eRHIC has very large tunability range of c.m. energies while maintaining very high luminosity up to 1034 cm-2 s-1 per nucleon. Two of the most attractive features of this scheme are full spin transparency of the ERL at all operational energies and the capability to support up to four interaction points. We present two main layouts of the eRHIC, the expected beam and luminosity parameter, and discuss the potential limitation of its performance.

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

TPPP051 A Muon Cooling Ring with Curved Lithium Lenses emittance, simulation, scattering, factory 3167
  • Y. Fukui, D. Cline, A.A. Garren
    UCLA, Los Angeles, California
  • H.G. Kirk
    BNL, Upton, Long Island, New York
  We design a muon cooling ring with curved Lithium lenses for the 6 dimensional muon phase space cooling. The cooling ring can be the final muon phase space cooling ring for a Higgs Factory, a low energy muon collider.Tracking simulation shows promising muon cooling with simplified magneti element models.  
TPPP053 Thin RF Windows for High-Pressure Gas-Filled Cavities vacuum, beam-cooling, linac, scattering 3224
  • M. Alsharo'a, R.P. Johnson
    Muons, Inc, Batavia
  • M. Gosz, D.M. Kaplan, S. Nair
    Illinois Institute of Technology, Chicago, Illinois
  • A. Moretti, G. Romanov
    Fermilab, Batavia, Illinois
  Funding: This work was supported in part by DOE STTR grant DE-FG02-02ER86145.

RF cavities for muon ionization cooling channels can have RF windows over their ends to create better internal voltage profiles and to make them independent of each other. To be effective, the conducting window material must be sufficiently transparent to the muons to not affect the beam cooling, which means low mass and low Z. In the case of pressurized RF cavities, as to opposed to those that operate in vacuum, the RF window design is simplified because the heat deposited in the windows from the RF and the beam is carried off by the hydrogen gas. In this report we analyze the thermal, mechanical, and electrical properties of a simple beryllium grid structure to improve the performance of pressurized RF cavities that are to be used for muon beam cooling.

TPPP054 Studies of RF Breakdown of Metals in Dense Gases resonance, klystron, hadron, vacuum 3259
  • P.M. Hanlet, M. Alsharo'a, R.P. Johnson, M. Kuchnir, K. Paul
    Muons, Inc, Batavia
  • C.M. Ankenbrandt, A. Moretti, M. Popovic, V. Yarba
    Fermilab, Batavia, Illinois
  • D.M. Kaplan, K. Yonehara
    Illinois Institute of Technology, Chicago, Illinois
  Funding: This work was supported in part by DOE STTR grant DE-FG02-02ER86145.

A study of RF breakdown of metals in gases has begun as part of a program to develop RF cavities filled with dense hydrogen gas to be used for muon ionization cooling. A pressurized 800 MHz test cell has been used at Fermilab to compare the conditioning and breakdown behavior of copper, molybdenum, chromium, and beryllium electrodes as functions of hydrogen and helium gas density. These results are compared to the predicted or known RF breakdown behavior of these metals in vacuum.

TPPP055 Simultaneous Bunching and Precooling Muon Beams with Gas-Filled RF Cavities target, emittance, simulation, factory 3295
  • K. Paul, R.P. Johnson, T.J. Roberts
    Muons, Inc, Batavia
  • Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • D.V. Neuffer
    Fermilab, Batavia, Illinois
  Funding: This work was supported in part by DOE SBIR grant DE-FG02-03ER83722.

High-gradient, pressurized RF cavities are investigated as a means to improve the capture efficiency, to effect phase rotation to reduce momentum spread, and to reduce the angular divergence of a muon beam. Starting close to the pion production target to take advantage of the short incident proton bunch, a series of pressurized RF cavities imbedded in a strong solenoidal field is used to capture, cool, and bunch the muon beam. We discuss the anticipated improvements from this approach to the first stage of a muon cooling channel as well as the requirements of the RF cavities needed to provide high gradients while operating in intense magnetic and radiation fields.

TPPP056 MANX, A 6-D Muon Cooling Demonstration Experiment emittance, quadrupole, dipole, factory 3331
  • T.J. Roberts, M. Alsharo'a, P.M. Hanlet, R.P. Johnson, M. Kuchnir, K. Paul
    Muons, Inc, Batavia
  • C.M. Ankenbrandt, A. Moretti, M. Popovic, V. Yarba
    Fermilab, Batavia, Illinois
  • D.M. Kaplan, K. Yonehara
    Illinois Institute of Technology, Chicago, Illinois
  Funding: This work was supported in part by DOE SBIR grant DE-FG02-04ER84015.

Most ionization cooling schemes now under consideration are based on using many large flasks of liquid hydrogen energy absorber. One important example is the proposed Muon Ionization Cooling Experiment (MICE), which has recently been approved to run at the Rutherford Appleton Laboratory (RAL). In the work reported here, a potential muon cooling demonstration experiment based on a continuous liquid energy absorber in a helical cooling channel (HCC) is discussed. The original HCC used a gaseous energy absorber for the engineering advantage of combining the energy absorption and RF energy regeneration in hydrogen-filled RF cavities. In the Muon And Neutrino eXperiment (MANX) that is proposed here, a liquid-filled HCC is used without RF energy regeneration to achieve the largest possible cooling rate in six dimensions. In this case, the magnetic fields of the HCC must diminish as the muons lose momentum as they pass through the liquid energy absorber. The length of the MANX device is determined by the maximum momentum of the muon test beam and the maximum practical field that can be sustained at the magnet coils. We have studied a 3 meter-long HCC example that could be inserted between the MICE spectrometers at RAL.

TPPT009 High Gradient Study at KEK on X-Band Accelerator Structure for Linear Collider linear-collider, linac, cathode, vacuum 1162
  • T. Higo, M. Akemoto, A. Enomoto, S. Fukuda, H. Hayano, N.K. Kudo, S.M. Matsumoto, T. Saeki, N. Terunuma, N. Toge, K.W. Watanabe
    KEK, Ibaraki
  • T.S. Suehara
    University of Tokyo, Tokyo
  We have fabricated accelerator structures for linear collider of the warm X-band design. These were composed of high-precision-machined parts for reliable wake-field suppression and possible cheap mass production. The structure design is mostly based on GLC/NLC design in collaboration with SLAC but the fabrication and the high-power test are being performed at KEK to conclude the feasibility, though the application to the present linear collider project was terminated. In this paper are presented the high gradient performance of these structures, such as the initial conditioning characteristics, the stability under high-field operation and various characteristics at high-gradient operation. We conclude that the stability requirement for the linear collider of the warm X-band design is barely satisfied but the preservation of the stability over very long period of more than several years is to be further studied.  
TPPT029 Fabrication of the Prototype 201.25 MHz Cavity for a Muon Ionization Cooling Experiment factory, electron, vacuum, instrumentation 2080
  • R.A. Rimmer, S. Manning, R. Manus, H.L. Phillips, M. Stirbet, K. Worland, G. Wu
    Jefferson Lab, Newport News, Virginia
  • R.A. Hafley, R.E. Martin, K.M. Taminger
    NASA Langley, Hampton, Virginia
  • D. Li, R.A. MacGill, J.W.  Staples, S.P. Virostek, M.S. Zisman
    LBNL, Berkeley, California
  • M. Reep, D.J. Summers
    UMiss, University, Mississippi
  Funding: This manuscript has been authored by SURA, Inc. under DoE Contract No. DE-AC05-84ER-40150, LBNL contract No. DE-AC03-76SF00098 and NASA contract IA1-533 subagreement #2

We describe the fabrication and assembly of the first prototype 201.25 MHz copper cavity for the muon ionization cooling experiment (MICE). This cavity was developed by the US MUCOOL collaboration and will be tested in the new Muon Test Area at Fermilab. We outline the component and subassembly fabrication steps and the various metal forming and joining methods used to produce the final cavity shape. These include spinning, brazing, TIG welding, electron beam welding, electron beam annealing and deep drawing. Assembly of the loop power coupler will also be described. Final acceptance test results are included. Some of the methods developed for this cavity are novel and offer significant cost savings compared to conventional construction methods.

TPPT030 RF, Thermal and Structural Analysis of the 201.25 MHz Muon Ionization Cooling Cavity vacuum, factory, impedance 2119
  • S.P. Virostek, D. Li
    LBNL, Berkeley, California
  Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC03-76SF00098.

A finite element analysis has been carried out to characterize the RF, thermal and structural behavior of the prototype 201.25 MHz cavity for a muon ionization cooling channel. A single ANSYS model has been developed to perform all of the calculations in a multi-step process. The high-gradient closed-cell cavity is being designed and fabricated for the MUCOOL and MICE (international Muon Ionization Cooling Experiment) experiments. The 1200 mm diameter cavity is constructed of 6 mm thick copper sheet and incorporates a rounded pillbox-like profile with an open beam iris terminated by 420 mm diameter, 0.38 mm thick curved beryllium foils. Tuning is accomplished through elastic deformation of the cavity, and cooling is provided by external water passages. Details of the analysis methodology will be presented including a description of the ANSYS macro that computes the heat loads from the RF solution and applies them directly to the thermal model. The process and results of a calculation to determine the resulting frequency shift due to thermal and structural distortion of the cavity will be presented as well.

TPPT044 Beam Position Monitoring Using the HOM-Signals from a Damped and Detuned Accelerating Structure linac, linear-collider, alignment, dipole 2804
  • S. Doebert, C. Adolphsen, R.M. Jones, J.R. Lewandowski, Z. Li, M.T.F. Pivi, J.W. Wang
    SLAC, Menlo Park, California
  • T. Higo
    KEK, Ibaraki
  Funding: Work Supported by DOE Contract DE-AC02-76F00515.

The Next Linear Collider (NLC) and Global Linear Collider (GLC) designs require precision beam-to-accelerator-structure alignment to reduce the effect of short range wakefields. For this purpose, the HOM signals from the structure dipole mode damping ports would be used to determine the beam position in the structure, and then the structures would be moved remotely to center them about the beam (a 5 micron rms alignment is required). In 2000, a test of a 1.8 m prototype structure in the ASSET facility at SLAC achieved 11 micron rms centering accuracy, which was limited by systematic effects caused by beam jitter. This year, such measurements were repeated for a pair of shorter structures (60 cm) that were developed to improve high gradient performance. In addition, the beam position resolution was determined by measuring simultaneously three signal frequencies (14.3, 15, 15.7 GHz) corresponding to modes localized at the beginning, the middle and the end of the structures. In this paper, we present results from the beam centering and position resolution measurements.

TPPT056 Design of a Low Loss SRF Cavity for the ILC damping, dipole, linac, linear-collider 3342
  • J.S. Sekutowicz
    DESY, Hamburg
  • L. Ge, K. Ko, L. Lee, Z. Li, C.-K. Ng, G.L. Schussman, L. Xiao
    SLAC, Menlo Park, California
  • I.G. Gonin, T.K. Khabiboulline, N. Solyak
    Fermilab, Batavia, Illinois
  • P. Kneisel
    Jefferson Lab, Newport News, Virginia
  • Y. Morozumi, K. Saito
    KEK, Ibaraki
  An international team comprising DESY, KEK, JLAB, FNAL and SLAC is collaborating on the design, fabrication and test of a low loss, 1.3 GHz 9-cell SRF structure as a potential improvement for the ILC main linac. The advantages of this structure over the TTF structure include lower cryogenic loss, shorter rise time, and less stored energy. Among the issues to be addressed in this design are HOM damping, Lorentz force detuning and multipacting. We will report on HOM damping calculations using the parallel finite element eigenmode solver Omega3P and the progress made towards an optimized design. Studies on multipacting and estimates of the Lorentz force detuning will also be presented.  
TPPT059 Improvement of the Blade Tuner Design for Superconducting RF Cavities linac, linear-collider, superconducting-RF, proton 3456
  • C. Pagani, A. Bosotti, P. Michelato, N. Panzeri, P. Pierini
    INFN/LASA, Segrate (MI)
  Funding: This work is partially supported by the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).

As of today, no complete technological solution exists for a cold tuning system fulfilling the requirements envisaged for the International Linear Collider, based on the superconducting RF technology. We present here the design improvements for the blade tuner, a coaxial device, which can provide both the slow structure tuning and the fast tuning capabilities needed for Lorentz Force Detuning (LFD) compensation and microphonics stabilitization (by means of the integration with a piezoelectric system). The system has been originally built by INFN and installed and tested at DESY on the superstructures, since it is located around the cavity helium vessel and does not require longitudinal clearance. Its design here is parametrically reviewed in terms of the requirements for higher accelerating fields and of the mechanical integration with a piezoelectric based system for the LFD and microphonics compensation.

TPPT068 Optimized Shape of Cavity Cells for Apertures Smaller than in TESLA Geometry acceleration, coupling, linear-collider, superconductivity 3748
  • V.D. Shemelin
    Cornell University, Ithaca, New York
  The accelerating rate (Eacc) of TESLA cavities can be increased for the same iris aperture if 1) some increase of Epk/Eacc is permitted so that the value of Hpk/Eacc can be lowered in comparison with the original cells (Epk and Hpk are maximal surface electric and magnetic fields); 2) shape of the cells is described by two elliptic arcs; 3) the reentrant cells obtained as a result of consecutive optimization with this geometry are treated as a possible version of cells in spite of some complications for fabrication. Not only the value of Hpk/Eacc can be improved but also values of cell-to-cell coupling and the geometry constants R/Q and G grow with the transition to the reentrant shapes. And these are not all benefits of this shape. The increased coupling prompts that the aperture of the original cell is big enough to be decreased without loss of field flatness in comparison with the original design. This decrease will lead to further increase of the Eacc for the same Hpk also as to improvement of others important parameters. Here, results of calculations for the original and for smaller apertures are presented and proposals for a better choice of TESLA cavity cells are derived.

Cornell University

TOPE002 Advances in Normal Conducting Accelerator Technology from the X-Band Linear Collider Program linear-collider, linac, klystron, gun 204
  • C. Adolphsen
    SLAC, Menlo Park, California
  In the early 1990's, groups at SLAC and KEK began dedicated development of X-band (11.4 GHz) rf technology for a next generation, TeV-scale linear collider. The choice of a relatively high frequency, four times that of the SLAC 50 GeV Linac, was motivated by the cost benefits of having lower rf energy per pulse (hence fewer rf components) and reasonable efficiencies at high gradients (hence shorter linacs). However, to realize such savings requires operation at gradients and peak powers much higher than that hitherto achieved. During the past 15 years, these challenges were met through innovations on several fronts, and resulted in a viable rf system design for a linear collider. This paper reviews these achievements, which include developments in the generation and transport of high power rf, and new insights into high gradient limitations.  
TOPE004 CLIC Progress Towards Multi-TeV Linear Colliders linac, luminosity, damping, emittance 353
  • H.-H. Braun
    CERN, Geneva
  Novel parameters of an e+/e- Linear Collider based on CLIC technology with a broad colliding energy range from 0.5 to 5 TeV are presented for an optimised luminosity of 8x1034 cm-2s-1 at the nominal energy of 3 TeV. They are derived in part from the very successful tests and experience accumulated in the CLIC Test facility, CTF2. A new and ambitious test facility, CTF3, presently under construction at CERN within an international collaboration of laboratories and institutes, and aimed at demonstrating the key feasibility issues of the CLIC scheme, is described.  
WOAA001 The International Linear Collider (ILC) Organization and Plans linear-collider, linac, damping, positron 94
  • M. Tigner
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  A discussion of the current organization and Central Team functions will be given. A plan for evolution of the organization towards governance by the funding agencies will be presented. The work plan for the first year will be described and today’s ideas of a possible timeline laid out.  
WOAA002 Progress and Plans for R&D and the Conceptual Design of the ILC Main Linacs linac, luminosity, klystron, coupling 199
  • H. Hayano
    KEK, Ibaraki
  The International Linear Collider Main Linacs are based on superconducting accelerator structures operating at 1.3 GHz. The basis for this design has been developed and tested at DESY and R&D is progressing at many laboratories around the world including DESY, Orsay, KEK, FNAL, SLAC, Cornell, and JLAB. The status of the TESLA-style cavities and rf system will be reviewed and parameters for the ILC linac will be described. The role of the different linac test facilities will discussed and the critical items and R&D program to support a Conceptual Design and Technical Design will be outlined.  
WOAA005 Progress and Plans for R&D and the Conceptual Design of the ILC High Gradient Structures micro-particles, superconductivity, electron, linear-collider 461
  • H. Padamsee
    Cornell University, Ithaca, New York
  Gradients and Q’s in the dominant ILC candidate structure have shown steady improvement, reaching 35–40 MV/m in the last year by using the best techniques of electropolishing, high pressure rinsing and 120 C baking for 48 hours. Progress and plans for t his structure will be reviewed. Above 40 MV/m, the surface magnetic field encroaches the rf critical magnetic field, believed to fall between 1750 and 2000 Oe, depending on the theory. One way to circumvent the limit is to modify the cavity shape to reduc e the ratio of peak magnetic to accelerating field. Two candidate shapes are evolving, the Re-entrant shape and the Low-Loss shape. Although field emission is aggravated by higher electric fields, it does not present a brick wall limit because high pressu re rinsing at 100 bar eliminates microparticles which cause field emission. Fundamental and higher mode properties of these new shapes will be compared with the dominant ILC candidate. Results of single and multicell cavities will be presented. The record field in a single cell re-entrant cavity is now 46 MV/m corresponding to a surface magnetic field of 1750 Oe and a surface electric field of 101 MV/m.N  
WPAE021 Short Straight Sections in the LHC Matching Sections (MS SSS): An Extension of the Arc Cryostats To Fulfill Specific Machine Functionalities vacuum, quadrupole, insertion, lattice 1724
  • V. Parma, H. Prin
    CERN, Geneva
  • fl. Lutton
    IPN, Orsay
  Funding: IPN-CNRS, 15 rue Georges Clémenceau 91406 ORSAY, France.

The LHC insertions require 50 specific superconducting quadrupoles, operating in boiling helium at 4.5 K and housed in individual cryostats to form the MS Short Straight Sections (MS SSS). The quadrupoles and corrector magnets are assembled in 8 families of cold masses, with lengths ranging from 5 to 11 m and weights ranging from 60 to 140 kN. The MS SSS need to fulfil specific requirements related to the collider topology, its cryogenic layout and the powering scheme. Most MS SSS are standalone cryogenic and super-conducting units, i.e. they are not in the continuous arc cryostat, and therefore need dedicated cryogenic and electrical feeding. Specially designed cryostat end-caps are required to close the vacuum vessels at each end, which include low heat in-leak Cold-to-Warm transitions (CWT) for the beam tubes and 6 kA local electrical feedthrough for powering the quadrupoles. This paper presents the design of the MS SSS cryostats as an extension of the arc cryostat’s design to achieve a standard and consequently cost-effective solution, and the design solutions chosen to satisfy their specific functionalities.

WPAE058 High Voltage Measurements on Nine PFNs for the LHC Injection Kicker Systems kicker, injection, simulation, power-supply 3402
  • M.J. Barnes, G.D. Wait
    TRIUMF, Vancouver
  • L. Ducimetière
    CERN, Geneva
  Funding: National Research Council of Canada

Each of the two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with a flattop duration variable up to 7.86 microseconds, and rise and fall times of less than 900 ns and 3 microseconds, respectively. A kicker magnet system consists of four 5 Ohm transmission line magnets with matching terminating resistors, four 5 Ohm Pulse Forming Networks (PFN) and two Resonant Charging Power Supplies (RCPS). Nine PFNs, together with associated switch tanks, and dump switch terminating resistors have been built at TRIUMF and all have been tested at high voltage (54 kV) to ensure that the performance is within specification. This paper describes the HV measurements, compares these results with low voltage measurements and analyses the pulse performance of the PFNs. The measurements are compared with results from PSpice simulations and small discrepancies between the predictions and measurements are explained.

WPAE066 PEP-II Large Power Supplies Rebuild Program at SLAC power-supply, controls, feedback, monitoring 3685
  • A.C. de Lira, P. Bellomo, J.J. Lipari, F.S. Rafael
    SLAC, Menlo Park, California
  Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.

At PEP-II, seven large power supplies (LGPS) are used to power quad magnets in the electron-positron collider region. The LGPS ratings range from 72kW to 270kW, and were installed in 1997. They are unipolar off-line switch mode supplies, with a 6 pulse bridge rectifying 480VAC, 3-phase input power to yield 650VDC unregulated. This unregulated 650VDC is then input into one (or two) IGBT H-bridges, which convert the DC into PWM 16 kHz square wave AC. This high frequency AC drives the primary side of a step-down transformer followed by rectifiers and low pass filters. Over the years, these LGPS have presented many problems mainly in their control circuits, making it difficult to troubleshoot and affecting the overall accelerator availability. A redesign/rebuilding program for these power supplies was established under the coordination of the Power Conversion Department at SLAC. During the 2004 accelerator summer shutdown all the control circuits in these supplies were redesigned and replaced. A new PWM control board, programmable logic controller, and touch panel were all installed to improve LGPS reliability, and to make troubleshooting easier. In this paper we present the details of this rebuilding program and results.

WPAT026 Status of 34 GHZ, 45 MW Pulsed Magnicon gun, electron, cathode, linear-collider 1922
  • O.A. Nezhevenko, V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  • J.L. Hirshfield, M.A. LaPointe
    Yale University, Physics Department, New Haven, CT
  • E.V. Kozyrev
    BINP SB RAS, Novosibirsk
  • S.V. Shchelkunov
    Columbia University, New York
  Funding: Research supported by the Department of Energy, Division of High Energy Physics.

A high efficiency, high power magnicon at 34.272 GHz has been designed and built as a microwave source to develop RF technology for a future multi-TeV electron-positron linear collider. To develop this technology, this new RF source is being perfected for necessary tests of accelerating structures, RF pulse compressors, RF components, and to determine limits of breakdown and metal fatigue. After preliminary RF conditioning the magnicon produced an output power of 10.5 MW in 0.25 microsecond pulses, with a gain of 54 dB. The new results of the experimental tests after the tube conditioning was resumed are presented in the paper.

WPAT045 A Non-Invasive Technique for Configuring Low Level RF Feedback Loops in PEP-II feedback, impedance, klystron, extraction 2863
  • D. Teytelman
    SLAC, Menlo Park, California
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

The RF system of the PEP-II collider uses two fast feedback loops around each klystron and set of cavities. These loops reduce the impedance of the fundamental mode of the accelerating cavities seen by the beam, and are necessary to reduce the growth rates of longitudinal modes within the RF system bandwidth. Operation of the accelerator at high beam currents is very sensitive to the configuration of the low-level RF feedback loops. There are 7 loop control parameters that strongly influence the stability of the feedback loops and the achieved level of longitudinal impedance reduction. Diagnostic techniques for the analysis of the RF feedback via closed-loop system transfer function measurements will be presented. The model is fit to the measured closed-loop transfer function data and the extracted parameters are then used to calculate optimal tuning and corrections to the loop control elements in the physical channel. These techniques allow fine-tuning of RF feedback with stored beam as well as diagnosis of mis-configured or malfunctioning elements of the system. Results from PEP-II operation will be presented to illustrate the techniques and their applications.

WPAT048 Solid State Modulators for the International Linear Collider (ILC) linear-collider, power-supply, target, controls 2998
  • M.A. Kempkes, N. Butler, J.A. Casey, M.P.J. Gaudreau, I. Roth
    Diversified Technologies, Inc., Bedford
  Diversified Technologies, Inc. is developing two solid state modulator designs for the ILC under SBIR funding from the DOE. The first design consists of a 150 kV hard switch. The key development in this design is the energy storage system, which must provide 25 kJ per pulse, at very tight voltage regulation over the 1.5 millisecond pulse. DTI’s design uses a quasi-resonant bouncer (with a small auxiliary power supply and switch) to maintain the voltage flattop, eliminating the need for massive capacitor banks. The second design uses a solid state Marx bank, with ~10 kV stages, to drive the ILC klystron. In this design, staggered turn-on of the Marx stages provides voltage regulation without the need for large capacitor banks. This paper will discuss design tradeoffs, power supply and control considerations, and energy storage requirements and alternatives for both designs.  
WPAT095 Low-Loss Ferroelectric for Accelerator Application coupling, vacuum, resonance, linear-collider 4305
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • A. Dedyk, S.F. Karmanenko
    Eltech University, St. Petersburg
  • E. Nenasheva
    Ceramics Ltd., St. Petersburg
  • V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  Funding: U.S. Department of Energy.

Ferroelectric ceramics have an electric field-dependent dielectric permittivity that can be altered by applying a bias voltage. Ferroelectrics have unique intrinsic properties that makes them attractive for high-energy accelerator applications: very small response time of ~ 10-11 sec, considerably high breakdown limit of more than 100 kV/cm, good vacuum properties. Because of these features, bulk ferroelectrics may be used as active elements of tunable accelerator structures,* or in fast, electrically - controlled switches and phase shifters in pulse compressors or power distribution circuits of future linear colliders.** One of the most critical requirements for ferroelectric ceramic in these applications is the dielectric loss factor. In this paper, the new bulk ferroelectric ceramic is presented. The new composition shows a loss tangent of 4× 10-3 at 35 GHz. The ceramics have high tunability factor: the bias voltage of 50 kV/cm was enough to reduce the permittivity from 500 to 400. The material chemical compound, features of the technology process, and mechanical and electrical properties are discussed. The ways of BST ferrolectric parameters further improvement are discussed as well.

*A. Kanareykin, W. Gai, J. Power, E. Sheinman, and A. Altmark, AIP Conf. Proc. 647, Melville, N.Y., 2002, p. 565. **V.P. Yakovlev, O.A. Nezhevenko, J.L. Hirshfield, and A.D. Kanareykin, AIP Conf. Proc. 691, Melville, N.Y., 2003, p.187.

ROAA005 Recent Innovations in Muon Beam Cooling and Prospects for Muon Colliders emittance, simulation, beam-cooling, resonance 419
  • R.P. Johnson, M. Alsharo'a, P.M. Hanlet, R. E. Hartline, M. Kuchnir, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
  • C.M. Ankenbrandt, E. Barzi, L. DelFrate, I.G. Gonin, A. Moretti, D.V. Neuffer, M. Popovic, G. Romanov, D. Turrioni, V. Yarba
    Fermilab, Batavia, Illinois
  • K. Beard, S.A. Bogacz, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • D.M. Kaplan, K. Yonehara
    Illinois Institute of Technology, Chicago, Illinois
  Funding: This work was supported in part by DOE SBIR/STTR grants DE-FG02-02ER86145, 03ER83722, 04ER84015, 04ER86191, and 04ER84016.

A six-dimensional(6D)cooling channel based on helical magnets surrounding RF cavities filled with dense hydrogen gas* is used to achieve the small transverse emittances demanded by a high-luminosity muon collider. This helical cooling channel**(HCC) has solenoidal, helical dipole, and helical quadrupole magnetic fields to generate emittance exchange. Simulations verify the analytic predictions and have shown a 6D emittance reduction of over 3 orders of magnitude in a 100 m HCC segment. Using three such sequential HCC segments, where the RF frequencies are increased and transverse dimensions reduced as the beams become cooler, implies a 6D emittance reduction of almost six orders of magnitude. After this, two new post-cooling ideas can be employed to reduce transverse emittances to one or two mm-mr, which allows high luminosity with fewer muons than previously imagined. In this report we discuss the status of and the plans for the HCC simulation and engineering efforts. We also describe the new post-cooling ideas and comment on the prospects for a Higgs factory or energy frontier muon collider using existing laboratory infrastructure.

*R. P. Johnson et al. LINAC2004, www.muonsinc.com/TU203.pdf. **Y. Derbenev and R.P. Johnson, Submitted to PRSTAB, http://www-mucool.fnal.gov/mcnotes/public/pdf/muc0284/muc0284.pdf.

ROAC004 High Gradient Performance of NLC/GLC X-Band Accelerating Structures linear-collider, vacuum, linac, target 372
  • S. Doebert, C. Adolphsen, G.B. Bowden, D.L. Burke, J. Chan, V.A. Dolgashev, J.C. Frisch, R.K. Jobe, R.M. Jones, R.E. Kirby, J.R. Lewandowski, Z. Li, D.J. McCormick, R.H. Miller, C.D. Nantista, J. Nelson, C. Pearson, M.C. Ross, D.C. Schultz, T.J. Smith, S.G. Tantawi, J.W. Wang
    SLAC, Menlo Park, California
  • T.T. Arkan, C. Boffo, H. Carter, I.G. Gonin, T.K. Khabiboulline, S.C. Mishra, G. Romanov, N. Solyak
    Fermilab, Batavia, Illinois
  • Y. Funahashi, H. Hayano, N. Higashi, Y. Higashi, T. Higo, H. Kawamata, T. Kume, Y. Morozumi, K. Takata, T. T. Takatomi, N. Toge, K. Ueno, Y. Watanabe
    KEK, Tsukuba, Ibaraki
  Funding: Work Supported by DOE Contract DE-AC02-76F00515.

During the past five years, there has been an concerted effort at FNAL, KEK and SLAC to develop accelerator structures that meet the high gradient performance requirements for the Next Linear Collider (NLC) and Global Linear Collider (GLC) initiatives. The structure that resulted is a 60-cm-long, traveling-wave design with low group velocity (< 4% c) and a 150 degree phase advance per cell. It has an average iris size that produces an acceptable short-range wakefield in the linacs, and dipole mode damping and detuning that adequately suppresses the long-range wakefield. More than eight such structures have operated over 1000 hours at a 60 Hz pulse rate at the design gradient (65 MV/m) and pulse length (400 ns), and have reached breakdown rate levels below the limit for the linear collider. Moreover, the structures are robust in that the breakdown rates continue to decrease over time, and if the structures are briefly exposed to air, the rates recover to their low values within a few days. This paper presents a final summary of the results from this program, which effectively ended last August with the selection of ‘cold’ technology for a next generation linear collider.

RPAT032 An Ionization Profile Monitor for the Tevatron vacuum, electron, ion, injection 2227
  • A. Jansson, M. Bowden, K. Bowie, A. Bross, R. Dysert, T. Fitzpatrick, R. Kwarciany, C. Lundberg, H. Nguyen, C.H. Rivetta, D. Slimmer, L. Valerio, J.R. Zagel
    Fermilab, Batavia, Illinois
  Funding: Work supported by the U.S. Department of Energy.

Primarily to study emittance blowup during injection and ramping, an ionization profile monitor has been developed for the Tevatron. It is based on a prototype installed in the Main Injector, although with extensive modifications. In particular, the electromagnetic shielding has been improved, the signal path has been cleaned up, and provisions have been made for an internal electron source. Due to the good Tevatron vacuum, a local pressure bump is introduced to increase the primary signal, which is then amplified by a microchannel plate and detected on anode strips. For the DAQ, a custom ASIC developed for the CMS experiment is used. It is a combined charge integrator and digitizer, with a sensitivity of a few fC, and a time-resolution that allows single bunch measurement. Digitization is done in the tunnel to reduce noise. Preparations for detector installation were made during the long 2004 shutdown, with the installation of magnets, vacuum chambers, vacuum pumps and cabling. The actual detector will be installed sometime during the spring fo 2005. This paper describes the design of the detector and associated electronics and presents various bench test results.

RPAT036 Measurement of the Intensity of the Beam in the Abort Gap at the Tevatron Utilizing Synchrotron Light synchrotron, radiation, 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.

RPAT083 Beam Profile Measurements and Simulations of the PETRA Laser-Wire laser, electron, photon, simulation 4123
  • J. Carter, I.V. Agapov, G.A. Blair, G.E. Boorman, C.D. Driouichi, F. Poirier, M.T. Price
    Royal Holloway, University of London, Surrey
  • K. Balewski, H.-C. Lewin, S. Schreiber, K. Wittenburg
    DESY, Hamburg
  • S.T. Boogert, S. Malton
    UCL, London
  • N. Delerue, D.F. Howell
    OXFORDphysics, Oxford, Oxon
  • T.  Kamps
    BESSY GmbH, Berlin
  The laser-wire will be an essential diagnostic tool at the International Linear Collider and advanced light sources. It uses a finely focussed laser beam to measure the transverse profile of electron bunches by detecting the Compton-scattered photons (or electrons) downstream of where the laser beam intersects the electron beam. Such a system has been installed at the PETRA storage ring at DESY, which uses a piezo-driven mirror to scan the laser light across the electron beam. Latest experimental results are presented and compared to detailed simulations using Geant4.  
ROAD001 Recent Progress in Power Refrigeration Below 2 K for Superconducting Accelerators vacuum, SNS, hadron, superconductivity 9
  • S.D. Claudet
    CERN, Geneva
  As a result of technico-economical optimization and quest for increased performance, 2 K cryogenics is now present in large accelerator projects using superconducting magnets or acceleration cavities. Consequently, large cryogenic systems producing refrigeration capacity below 2 K in the kW range and with high efficiency over a large dynamic range are needed. After CEBAF and SNS, this is now the case for the Large Hadron Collider (LHC) project at CERN for which eight 2.4 kW @ 1.8 K refrigeration units are needed to cool each a 3.3 km long sector of high-field magnets. Combining cold hydrodynamic compressors in series with warm volumetric compressors, complete pre-series units as well as sets of series cold compressors have been intensively tested and validated from two different industrial suppliers. After recalling the possible 2 K refrigeration cycles and their comparative merits, this paper describes the specific features of the LHC system and presents the achieved performance with emphasis on the progress in terms of efficiency, operational compliance, reliability and maintenance. Perspectives of application to a future International Linear Collider based on cold RF technology are then briefly evoked.  
ROPB001 Suppressing Electron Cloud in Future Linear Colliders electron, simulation, damping, vacuum 24
  • M.T.F. Pivi, R.E. Kirby, T.O. Raubenheimer
    SLAC, Menlo Park, California
  • F. Le Pimpec
    PSI, Villigen
  Funding: Work supported by the U.S. DOE under contract DE-AC02- 76SF00515.

Any accelerator circulating positively charged beams can suffer from a build-up of an electron cloud in the beam pipe. The cloud develops through ionization of residual gases, synchrotron radiation and secondary electron emission and, when severe, can cause instability, emittance blow-up or loss of the circulating beam. The electron cloud is potentially a limiting effect for both the Large Hadron Collider (LHC) and the International Linear Collider (ILC). For the ILC positron damping ring, the development of the electron cloud must be suppressed. This paper presents the various effects of the electron cloud and evaluates their significance. It also discusses the state-of-the-art of the ongoing international R&D program to study potential remedies to reduce the secondary electron yield to acceptably low levels.

RPPE061 SRF Accelerator Technology Transfer Experience from the Achievement of the SNS Cryomodule Production Run SNS, superconducting-RF, vacuum, linear-collider 3517
  • J. Hogan, T.C. Cannella, E. Daly, M. A. Drury, J.F. Fischer, T. Hiatt, P. Kneisel, J. Mammosser, J.P. Preble, T.E. Whitlatch, K. Wilson, M. Wiseman
    Jefferson Lab, Newport News, Virginia
  This paper will discuss the technology transfer aspect of superconducting RF expertise, as it pertains to cryomodule production, beginning with the original design requirements through testing and concluding with product delivery to the end user. The success of future industrialization, of accelerator systems, is dependent upon a focused effort on accelerator technology transfer. Over the past twenty years the Thomas Jefferson National Accelerator Facility (Jefferson Lab) has worked with industry to successfully design, manufacture, test and commission more superconducting RF cryomodules than any other entity in the United States. The most recent accomplishment of Jefferson Lab has been the successful production of twenty-four cryomodules designed for the Spallation Neutron Source (SNS). Jefferson Lab was chosen, by the United States Department of Energy, to provide the superconducting portion of the SNS linac due to its reputation as a primary resource for SRF expertise. The successful partnering with, and development of, industrial resources to support the fabrication of the superconducting RF cryomodules for SNS by Jefferson Lab will be the focus of this paper.  
RPPP003 Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider optics, damping, linear-collider, extraction 874
  • H. Hayano, S. Araki, H. Hayano, Y. Higashi, Y. Honda, K.-I. Kanazawa, K. Kubo, T. Kume, M. Kuriki, S. Kuroda, M. Masuzawa, T. Naito, T. Okugi, R. Sugahara, T. Tauchi, N. Terunuma, N. Toge, J.U. Urakawa, V.V. Vogel, H. Yamaoka, K. Yokoya
    KEK, Ibaraki
  • I.V. Agapov, G.A. Blair, G.E. Boorman, J. Carter, C.D. Driouichi, M.T. Price
    Royal Holloway, University of London, Surrey
  • D.A.-K. Angal-Kalinin, R. Appleby, J.K. Jones, A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • P. Bambade
    LAL, Orsay
  • K.L.F. Bane, A. Brachmann, T.M. Himel, T.W. Markiewicz, J. Nelson, N. Phinney, M.T.F. Pivi, T.O. Raubenheimer, M.C. Ross, R.E. Ruland, A. Seryi, C.M. Spencer, P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  • S.T. Boogert, A. Liapine, S. Malton
    UCL, London
  • H.-H. Braun, D. Schulte, F. Zimmermann
    CERN, Geneva
  • P. Burrows, G.B. Christian, S. Molloy, G.R. White
    Queen Mary University of London, London
  • J.Y. Choi, J.Y. Huang, H.-S. Kang, E.-S. Kim, S.H. Kim, I.S. Ko
    PAL, Pohang, Kyungbuk
  • S. Danagoulian
    North Carolina A&T State University, Greensboro, North Carolina
  • N. Delerue, D.F. Howell, A. Reichold, D. Urner
    OXFORDphysics, Oxford, Oxon
  • J. Gao, W. Liu, G. Pei, J.Q. Wang
    IHEP Beijing, Beijing
  • B.I. Grishanov, P.L. Logachev, F.V. Podgorny, V.I. Telnov
    BINP SB RAS, Novosibirsk
  • J.G. Gronberg
    LLNL, Livermore, California
  • Y. Iwashita, T. Mihara
    Kyoto ICR, Uji, Kyoto
  • M. Kumada
    NIRS, Chiba-shi
  • S. Mtingwa
    North Carolina University, Chapel Hill, North Carolina
  • O. Napoly, J. Payet
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • T.S. Sanuki, T.S. Suehara
    University of Tokyo, Tokyo
  • T. Takahashi
    Hiroshima University, Higashi-Hiroshima
  • E.T. Torrence
    University of Oregon, Eugene, Oregon
  • N.J. Walker
    DESY, Hamburg
  The realization of the International Linear Collider (ILC) will require the ability to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittancies are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 35nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.  
RPPP013 Tests of the FONT3 Linear Collider Intra-Train Beam Feedback System at the ATF feedback, kicker, linear-collider, electron 1359
  • P. Burrows, G.B. Christian, C.C. Clarke, A.F. Hartin, H.D. Khah, S. Molloy, G.R. White
    Queen Mary University of London, London
  • J.C. Frisch, T.W. Markiewicz, D.J. McCormick, M.C. Ross, S. Smith, T.J. Smith
    SLAC, Menlo Park, California
  • A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • C. Perry
    OXFORDphysics, Oxford, Oxon
  We report preliminary results of beam tests of the FONT3 Linear Collider intra-train position feedback system prototype at the Accelerator Test Facility at KEK. The feedback system incorporates a novel beam position monitor (BPM) processor with a latency below 5 nanoseconds, and a kicker driver amplifier with similar low latency. The 56 nanosecond-long bunchtrain in the ATF extraction line was used to test the prototype with delay-loop feedback operation. The achieved latency represents a demonstration of intra-train feedback on timescales relevant even for the CLIC Linear Collider design.  
RPPP019 Revisiting the Cold ILC Parameters damping, linac, luminosity, feedback 1661
  • H. Padamsee
    Cornell University, Ithaca, New York
  At the first ILC Workshop, discussions were underway to re-examine the parameters of the cold ILC. Using the TESLA parameters MathCad program developed in 1991, I examined several variations to explore consequences to the capital and operating costs of the linac (cryomodules, RF, & refrigerator). The cost coefficients were chosen to match the distribution of the above items in the TESLA TDR at 25 MV/m. One parameter varied is the gradient from 25 to 50 MV/m coupled with a realistic Q as well as an optimistic Q (1010). Other parameters varied are: number of bunches, spacing, and rep rate to decrease the damping ring size. Keeping all other TDR parameters the same, the optimal gradient for the realistic Q curve is about 35 MV/m, yielding a capital cost savings of 16% and a total cost savings of 9% over the nominal gradient of 25 MV/m. If however the Q remains at 1010, the optimum gradient moves to 50 MV/m where the total cost savings rise to 17.5%, and capital cost savings rise to 35%. Of course, gradients higher than 35 MV/m are extremely challenging, demanding major development efforts, such as control of Lorentz force detuning which increases as the square of the gradient.  
RPPP021 Multivariate Optimization of ILC Parameters linac, luminosity, emittance, linear-collider 1736
  • I.V. Bazarov
    Cornell University, Department of Physics, Ithaca, New York
  • H. Padamsee
    Cornell University, Ithaca, New York
  Funding: This work is supported by the NSF.

We present results of multiobjective optimization of the International Linear Collider (ILC) which seeks to maximize luminosity at each given total cost of the linac (capital and operating costs of cryomodules, refrigeration and RF). Evolutionary algorithms allow quick exploration of optimal sets of parameters in a complicated system such as ILC in the presence of realistic constraints as well as investigation of various what-if scenarios in potential performance. Among the parameters we varied there were accelerating gradient and Q of the cavities (in a coupled manner following a realistic Q vs. E curve), the number of particles per bunch, the bunch length, number of bunches in the train, etc. We find an optimum which decreases (relative to TDR baseline) the total linac cost by 22 %, capital cost by 25 % at the same luminosity of 3·1038 1/m2/s. For this optimum the gradient is 35 MV/m, the final spot size is 3.6 nm, and the beam power is 15.9 MW. Dropping the luminosity to 2·1038 1/m2/s results in an additional 8 % reduction in the total linac cost. We have also explored the optimal fronts of luminosity vs. cost for several other scenarios using the same approach.

RPPP028 Simulation of Wake Field Effects on High Energy Particle Beams collimation, linear-collider, simulation, optics 2018
  • R.J. Barlow, G.Yu. Kourevlev, A. Mercer
    UMAN, Manchester
  We discuss the wake fields that are liable to arise in the Beam Delivery System of a Future Linear Collider, and we present studies made using the MERLIN simulation program of the effects such fields would have on the bunch shape and hence the luminosity of the proposed design.  
RPPP036 A Test Facility for the International Linear Collider at SLAC End Station A for Prototypes of Beam Delivery and IR Components insertion, synchrotron, linear-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).

FOAC002 Status of Neutrino Factory Design and R&D factory, target, proton, simulation 209
  • D. Li
    LBNL, Berkeley, California
  Funding: Work supported by the US Department of Energy under contract No. DE-AC0376SF00098

Neutrino physics has become increasingly interesting to the high-energy physics community, as it may provide clues to new physics beyond the standard model. The physics potential of a Neutrino Factory–a facility to produce high-energy, high-intensity, high-brightness neutrino beams from decays of muons stored in a muon storage ring–is thus very high. There has been a global R&D effort aimed at a Neutrino Factory design that meets the physics requirements and addresses the key technologies, such as targetry, muon ionization cooling and acceleration. Tremendous progress has been made in the past few years in many aspects of accelerator technology. In this paper, we will review recent worldwide progress toward a cost-effective Neutrino Factory design, with emphasis on the associated R&D programs under the auspices of the U.S. Neutrino Factory and Muon Collider Collaboration.

FPAE008 Iso-Adiabatic Merging of pbar Stacks in the Recycler emittance, simulation, antiproton, hadron 1093
  • C.M. Bhat
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Association, Inc., under contract DE-AC02-76CH03000 with the U.S. Department of Energy.

Here, I have proposed an efficient scheme to merge two stacks of pbars in the Recycler* with emittance dilution <15%. First I discuss a method to match energy spreads of the two stacks and subsequently merging them. The scheme is illustrated with multiparticle dynamics simulations and beam measurements in the Recycler.

*G. Jackson, Fermilab-TM-1991, November, 1996.

FPAE009 Bunched Beam Cooling in the Fermilab Recycler emittance, synchrotron, 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.  
FPAE012 Experimental Test of a New Antiproton Acceleration Scheme in the Fermilab Main Injector emittance, acceleration, antiproton, injection 1303
  • V. Wu, C.M. Bhat, B. Chase, J.E. Dey, K.G. Meisner
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association, Inc. for the U.S. Department of Energy under contract DE-AC02-76CH03000.

In an effort to provide higher intensity and lower emittance antiproton beam to the Tevatron collider for high luminosity operation, a new Main Injector (MI) antiproton acceleration scheme has been developed [1-4].* In this scheme, beam is accelerated from 8 to 27 GeV using the 2.5 MHz rf system and from 27 to 150 GeV using the 53 MHz rf system. This paper reports the experimental results of beam study. Simulation results are reported in a different PAC'05 paper [5]. Experiments are conducted with proton beam from the Booster. Acceleration efficiency, emittance growth and beam harmonic transfer between 2.5 MHz (h=28) and 53 MHz (h=588) buckets have been studied. Beam study shows that one can achieve an overall acceleration efficiency of about 100%, longitudinal emittance growth less than 20% and negligible transverse emittance growth.

*G. P. Jackson, The Fermilab Recycler Ring Technical Design Report, FERMILAB-TM-1991, November 1996.

FPAE073 A Free Hg Jet System for Use in a High-Power Target Experiment target, proton, diagnostics, laser 3895
  • P.T. Spampinato, T.A. Gabriel, V.B. Graves, M.J. Rennich
    ORNL, Oak Ridge, Tennessee
  • A. Fabich, H. Haseroth, J. Lettry
    CERN, Geneva
  • H.G. Kirk, N. Simos, T. Tsang
    BNL, Upton, Long Island, New York
  • K.T. McDonald
    PU, Princeton, New Jersey
  • P. Titus
    MIT/PSFC, Cambridge, Massachusetts
  Funding: Work funded by the U.S. Department Of Energy.

We describe a mercury jet system that is suitable for insertion into the 15cm diameter bore of a high-field solenoid magnet. The device features a hermetically sealed primary containment volume which is enclosed in a secondary containment system to insure isolation of mercury vapors from the remaining experimental environment. The jet diameter is 1-cm while the jet velocity will be up to 20 m/s. Optical diagnostics is incorporated into the target design to allow observation of the dispersal of the mercury as a result of interaction with a 24 GeV proton beam with up to 20 x 1012 ppp.

FPAT005 A Betatron Tune Fitting Package for the Tevatron 21.4 MHz Schottky betatron, synchrotron, antiproton, 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.  
FPAT007 The Fermilab Lattice Information Repository lattice, optics, antiproton, coupling 1066
  • J.-F. Ostiguy, M. Kriss, M. McCusker-Whiting, L. Michelotti
    Fermilab, Batavia, Illinois
  Funding: Fermilab is operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

Fermilab is a large accelerator complex with six rings and sixteen transfer beamlines operating in various modes and configurations, subject to modifications, improvements and occasional major redesign. Over the years, it became increasingly obvious that a centralized lattice repository with the ability to track revisions would be of great value. To that end, we evaluated potentially suitable revision systems, either freely available or commercial, and decided that expecting infrequent users to become fully conversant with complex revision system software was neither realistic nor practical. In this paper, we discuss technical aspects of the recently introduced FNAL Accelerator Division's Lattice Repository, whose fully web-based interface hides the complexity of Subversion, a comprehensive open source revision system. In particular we emphasize how the architecture of Subversion was a key ingredient in the technical success of the repository's implementation.

FPAT008 SDA-Based Diagnostic and Analysis Tools for Collider Run II proton, acceleration, diagnostics, controls 1099
  • V. Papadimitriou, T.B. Bolshakov, P. Lebrun, S. Panacek, A.J. Slaughter, A. Xiao
    Fermilab, Batavia, Illinois
  Funding: Fermilab (Department of Energy).

Operating and improving the understanding of the Fermilab Accelerator Complex for the colliding beam experiments requires advanced software methods and tools. The Shot Data Acquisition and Analysis (SDA) has been developed to fulfill this need. Data is stored in a relational database, and is served to programs and users via Web-based tools. Summary tables are systematically generated during and after a store. These tables, the Supertable, and the Recomputed Emittances and Recomputed Intensity tables are discussed here. This information is also accesible in JAS3 (Java Analysis Studio version 3).

FOAA006 Digital Low-Level RF Controls for Future Superconducting Linear Colliders linac, feedback, klystron, resonance 515
  • S. Simrock
    DESY, Hamburg
  The requirements for RF Control Systems of Superconducting Linear Colliders are not only defined in terms of the quality of field control but also with respect to operability, availability, and maintainability of the RF System, and the interfaces to other subsystems. The field control of the vector-sum of many cavities driven by one klystron in pulsed mode at high gradients is a challenging task since severe Lorentz force detuning, microphonics and beam induced field errors must be suppressed by several orders of magnitude. This is accomplished by a combination of local and global feedback and feedforward control. Sensors monitor individual cavity probe signals, and forward and reflected wave as well as the beam properties including beam energy and phase while actuators control the incident wave of the klystron and individual cavity resonance frequencies. The operability of a large llrf system requires a high degree of automation while the high availability requires robust algorithms, redundancy, and extremely reliable hardware. The maintenance of the llrf demands sophisticated on-line diagnostics for the llrf subsystems to minimize downtime.