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emittance

Paper Title Other Keywords Page
MOPA004 Status of Slip Stacking at Fermilab Main Injector beam-loading, target, injection, booster 347
 
  • K. Seiya, T. Berenc, B. Chase, J.E. Dey, I. Kourbanis, J.A. MacLachlan, K.G. Meisner, R.J. Pasquinelli, J. Reid, C.H. Rivetta, J. Steimel
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association, Inc. for the U.S. Department of Energy under contract DE-AC02-76CH03000.

In order to increase proton intensity on anti proton production cycle of the Main Injector we are going to use the technique of 'slip stacking' and doing machine studies. In slip stacking, one bunch train is injected at slightly lower energy and second train is at slightly higher energy. Afterwards they are aligned longitudinally and captured with one rf bucket. This longitudinal stacking process is expected to double the bunch intensity. The required intensity for anti proton production is 8·1012 protons in 84 bunches. Beam studies of the slip stacking process have started and we have already established that the stacking procedure works as expected for a low beam intensity. In order to make this stacking process usable for higher intensity beam in standard mode of operation, we are working on high intensity beam and the development of the feedback and feed forward system is under way.

 
 
MOPA006 Theory and Reality of Beam-Beam Effects at Hadron Colliders resonance, antiproton, proton, beam-beam-effects 544
 
  • Y. Alexahin
    Fermilab, Batavia, Illinois
  The beam-beam phenomena in hadron colliders is just as rich as in e+e- machines: orbit and focusing perturbations, excitation of nonlinear resonances, coherent tuneshifts. Moreover, the absence of radiation damping and long duration of a store permit even high-order (and correspondingly weak) resonances to manifest themselves presenting a major challenge for both theoretical analysis and machine operation. The recent progress in understanding of and coping with the beam-beam effects at hadron colliders, primarily at the Tevatron, is discussed.  
 
MOPC002 Benchmark of Space Charge Simulations and Comparison with Experimental Results for High Intensity, Low Energy Accelerators space-charge, simulation, linac, SNS 164
 
  • S.M. Cousineau
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

Space charge effects are a major contributor to beam halo and emittance growth leading to beam loss in high intensity, low energy accelerators. As future accelerators strive towards unprecedented levels of beam intensity and beam loss control, a more comprehensive understanding of space charge effects is required. A wealth of simulation tools have been developed for modeling beams in linacs and rings, and with the growing availability of high-speed computing systems, computationally expensive problems that were inconceivable a decade ago are now being handled with relative ease. This has opened the field for realistic simulations of space charge effects, including detailed benchmarks with experimental data. A great deal of effort is being focused in this direction, and several recent benchmark studies have produced remarkably successful results. This paper reviews the achievements in space charge benchmarking in the last few years, and discusses the challenges that remain.

 
 
MOPC003 Benchmarking of Simulation Codes Based on the Montague Resonance in the CERN Proton Synchrotron simulation, lattice, resonance, focusing 330
 
  • I. Hofmann, G. Franchetti
    GSI, Darmstadt
  • J.F. Amundson, P. Spentzouris
    Fermilab, Batavia, Illinois
  • S.M. Cousineau, J.A. Holmes
    ORNL, Oak Ridge, Tennessee
  • M. Giovannozzi, E. Métral
    CERN, Geneva
  • F.W. Jones
    TRIUMF, Vancouver
  • A.U. Luccio
    BNL, Upton, Long Island, New York
  • S. Machida
    KEK, Ibaraki
  • J. Qiang, R.D. Ryne
    LBNL, Berkeley, California
  Experimental data on emittance exchange by the space charge driven ‘‘Montague resonance'' have been obtained at the CERN Proton Synchrotron in 2002-04 as a function of the working point. These data are used to advance the benchmarking of major simulation codes (ACCSIM, IMPACT, MICROMAP, ORBIT, SIMBAD, SIMPSONS, SYNERGIA) currently employed world-wide in the design or performance improvement of high intensity circular accelerators. In this paper we summarize the experimental findings and compare them with the first three steps of simulation results of the still progressing work.  
 
MOPC008 Dynamic Beam-Beam Effects Measured at KEKB electron, beam-beam-effects, positron, luminosity 606
 
  • T. Ieiri, Y. Funakoshi, T. Kawamoto, M. Masuzawa, M. Tobiyama
    KEK, Ibaraki
  Funding: This work is partially supported by Grant-in-Aid Scientific Research (16540271) from Japan Society for the Promotion of Science and Technology.

KEKB is a multi-bunch, high-current, electron/positron collider for B meson physics. The two beams collide at one interaction point (IP) with a finite horizontal crossing angle and with a bunch-space of 6 to 8 ns. The luminosity achieved at KEKB is the best in the world. The betatron tunes are set close to a half integer, to expect the dynamic beam-beam effects that change the beta function around the rings and the emittance as a function of the beam-beam parameter. In order to investigate such attractive beam-beam effects, the beam-beam kick and the beam-beam tune-shift were obtained by comparing the beam parameters between a colliding bunch and a non-colliding one. The horizontal beam size at the IP estimated from a beam-beam kick curve was slightly less than a calculated value without the dynamic effect. The horizontal emittance estimated from the beam-beam tune shift was somewhat larger than a calculated natural emittance. These experimental results reflect the dynamic beam-beam effects.

 
 
MOPC009 Experiments on LHC Long-Range Beam-Beam Compensation and Crossing Schemes at the CERN SPS in 2004 simulation, dynamic-aperture, resonance, hadron 686
 
  • F. Zimmermann, J.-P. Koutchouk, F. Roncarolo, J. Wenninger
    CERN, Geneva
  • Y. Papaphilippou
    ESRF, Grenoble
  • T. Sen, V.D. Shiltsev
    Fermilab, Batavia, Illinois
  Experiments with two prototype long-range beam-beam compensators (current-carrying wires) during the 2004 CERN SPS run explored the efficiency of a proposed long-range beam-beam compensation for the LHC. In addition, the SPS compensators were also used to 'simulate' the effect of different planes of crossing at two LHC interaction points. We present the experimental results and compare them with computer simulations.  
 
MPPE011 Expected Emittance Growth and Beam Tail Repopulation from Errors at Injection into the LHC injection, betatron, coupling, simulation 1266
 
  • B. Goddard, H. Burkhardt, V. Kain, T. Risselada
    CERN, Geneva
  The preservation of the transverse emittance of the proton beam at injection into the LHC is crucial for luminosity performance. The population of the beam tails is also important for beam losses and collimation. The transfer and injection process is particularly critical in this respect, and several effects can contribute to the expected emittance increase and tail repopulation, like optical and geometrical mismatch, injection offsets and coupling, etc. The various effects are described, together with the tolerance limits on the parameters, and the expected contributions evaluated analytically where possible. The emittance growth and tail distributions are also simulated numerically using realistic errors. The implications for the tolerances on the matching of the transfer lines are discussed.  
 
MPPE013 High Precision Measurement of Muon Beam Emittance Reduction in MICE factory, simulation, background, scattering 1330
 
  • C.T. Rogers, M. Ellis
    Imperial College of Science and Technology, Department of Physics, London
  Muon ionization cooling, an essential ingredient of a neutrino factory, will be demonstrated for the first time by the MICE experiment. The central part of MICE consists of a short section of a neutrino factory cooling channel and the emittance reduction achieved in this experiment is quite modest, 10% to 15%. In order to extrapolate the performance of a full cooling channel from these values, it is crucial for MICE to achieve an emittance measurement accuracy of 10-3 absolute. So far, beam emittance has never been measured with such a high level of precision and normailzed emittance in its present definition is not even conserved to 10-3 in the absence of dissipative forces. We present an improved definition of beam emittance and the requirements and constraints on MICE beam optics and spectrometers that are necessary to achieve the 10-3 level of accuracy.  
 
MPPE016 Hamiltonian Analysis of Transverse Dynamics in Axisymmetric RF Photoinjector focusing, space-charge, acceleration, transverse-dynamics 1476
 
  • C.-X. Wang
    ANL, Argonne, Illinois
  A general Hamiltonian that governs the beam dynamics in an rf photoinjector is derived from first principles. With proper choice of coordinates, the resulting Hamiltonian has a simple and familiar form, while taking into account the rapid acceleration, rf focusing, magnetic focusing, and space-charge forces. From the linear Hamiltonian, beam-envelope evolution is readily obtained, which better illuminates the theory of emittance compensation. Preliminary results on the third-order nonlinear Hamiltonian will be given as well.  
 
MPPE017 Longitudinal Acceptance in Linear Non-Scaling FFAGs acceleration, longitudinal-dynamics, extraction, injection 1532
 
  • J.S. Berg
    BNL, Upton, Long Island, New York
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-98CH10886.

Linear Non-Scaling FFAGs have, particularly for muon acceleration, a unique type of longitudinal motion. This longitudinal motion can be approximated by a parabolic dependence time-of-flight on energy. This motion can be described in dimensionless variables with two parameters. I describe the relationship between the parameters and the distortion of ellipses in longitudinal space. I discuss the relationship between the longitudinal acceptance and the time spent in the FFAG, the latter being especially relevant for decays in muon accelerators. I discuss what improvement one can expect to achieve by adding higher-harmonic RF systems to the accelerator.

 
 
MPPE020 Control of Dynamic Aperture for Synchrotron Light Sources optics, sextupole, radiation, lattice 1670
 
  • J. Bengtsson
    BNL, Upton, Long Island, New York
  Funding: Under Contract with the U.S. Department of Energy Contract Number DE-AC02-98CH10886.

Given the following frameworks: "A Hamiltonian-Free Description of Single Particle Dynamics for Hopelessly Complex Periodic Systems" (Forest, 1990), "Normal Form Methods for Complicated Periodic Systems" (Forest, Berz, Irwin, 1989), "The Correct Local Description for Tracking in Rings" (Forest, 1994), "The C++ Programming Language" (Stroustrup, 1985), we have designed a compact object oriented beam dynamics class by re-using existing FORTRAN libraries for: Truncated Power Series Algebra (Berz, SSC, 1988), and Map Normal Rorm (Forest, CBP, LBNL, 1990). In other words, implemented a numerical- and analytical model for: 6-dim phase space tracking, with classical radiation, and evaluation of equilibrium emittance, driving terms, amplitude dependent tune shifts, chromaticity, momentum compaction, etc., to arbitrary order, with self-consistent treatment of magnet errors. The tool was developed for the lattice design of NSLS-II.

 
 
MPPE023 Improvement of the Longitudinal Beam Dynamics Tuning Procedure for the MSU RIA Driver Linac linac, lattice, focusing, ion 1826
 
  • M. Doleans
    MSU, East Lansing, Michigan
  • D. Gorelov, T.L. Grimm, F. Marti, X. Wu, R.C. York
    NSCL, East Lansing, Michigan
  The Rare Isotope Accelerator (RIA) driver linac will use a superconducting, cw linac with independently phased superconducting radio frequency cavities for acceleration and, for the heavier ions, utilize beams of multiple-charge-states (multi-q). Given the acceleration of multi-q beams and a stringent beam loss requirement in the RIA driver linac, a new beam envelope code capable of simulating nonlinearities of the multi-q beam envelopes in the longitudinal phase space was developed. Using optimization routines, the code is able to maximize the linearity of the longitudinal phase space motion and thereby minimizing beam loss by finding values for the amplitude and phase of the cavities for a given accelerating lattice. Relative motion of the multi-q beams is also taken into account so that superposition of the beam centroids and matching of their Twiss parameters are automatically controlled. As a result, the linac tuning procedure has been simplified and the longitudinal lattice performance has been improved. In this paper, the general architecture of the code and the results of using it to determine tuning parameters for the RIA driver linac are presented.  
 
MPPE024 Failure Modes Analysis for the MSU-RIA Driver Linac linac, lattice, focusing, simulation 1868
 
  • X. Wu, M. Doleans, D. Gorelov, T.L. Grimm, F. Marti, R.C. York
    NSCL, East Lansing, Michigan
  Previous end-to-end beam dynamics simulation studies* using experimentally-based input beams including alignment and rf errors and variation in charge-stripping foil thickness have indicated that the Rare Isotope Accelerator (RIA) driver linac proposed by MSU has adequate transverse and longitudinal acceptances to accelerate light and heavy ions to final energies of at least 400 MeV/u with beam powers of 100 to 400 kW. During linac operation, equipment loss due to, for example, cavity contamination, availability of cryogens, or failure of rf or power supply systems, will lead to at least a temporary loss of some of the cavities and focusing elements. To achieve high facility availability, each segment of the linac should be capable of adequate performance even with failed elements. Beam dynamics studies were performed to evaluate the linac performance under various scenarios of failed cavities and focusing elements with proper correction schemes, in order to prove the flexibility and robustness of the driver linac lattice design. The result of these beam dynamics studies will be presented.

*X. Wu, "End-to-End Beam Simulations for the MSU RIA Driver Linac," Proceedings of the XXII Linac Conference, Lubeck, Germany, August 2004.

 
 
MPPE044 Damping Wiggler Study at KEK-ATF wiggler, damping, power-supply, injection 2809
 
  • T. Naito, H. Hayano, Y. Honda, K. Kubo, M. Kuriki, S. Kuroda, T. Muto, N. Terunuma, J.U. Urakawa
    KEK, Ibaraki
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  • N. Nakamura, H. Sakai
    ISSP/SRL, Chiba
  • M.C. Ross
    SLAC, Menlo Park, California
  The effects by damping wiggler magnets have been studied at KEK-ATF. The damping ring of the KEK-ATF is a 1.3 GeV storage ring capable of producing ultra-low emittance electron beams. It is significant issue to realize fast damping in the damping ring. The tuning method with 4 sets of wiggler was investigated for the ultra-low emittance beam. The performance on the beam quality, which is related to the transverse (x and y) and the longitudinal (z and dp/p), has been measured by the SR monitor, the laser wire, the streak camera and the energy spread monitor at the extraction line. We report on the operation condition and the measurement results.  
 
MPPE045 Accelerator Physics Issues at the 2.5 GeV PLS Storage Ring lattice, insertion, insertion-device, undulator 2854
 
  • E.-S. Kim
    PAL, Pohang, Kyungbuk
  Over the past decade, PLS has served the synchrotron light source with the 2.0 GeV to 2.5 GeV electron beam. Accelerator physics issues at the present 2.5 GeV storage ring have been investigated in order to improve the performance of the light source. We present the issues of the low-beta lattice, low-emittance lattice, effects of six insertion devices on the lattice and low-alpha lattice, and show their effects on the beam dynamics in the storage ring.  
 
MPPE047 Optics Flexibility and Matching at LHC Injection optics, injection, quadrupole, alignment 2983
 
  • H. Burkhardt, O.S. Brüning, B. Goddard, V. Kain, V. Mertens, T. Risselada, A. Verdier
    CERN, Geneva
  An excellent match between the SPS, the several kilometers long transfer lines and the LHC will be required to minimise emittance blow-up at injection. Several optics changes in the SPS and the LHC injection insertions had to be accommodated in the design phase. The new 3-phase collimation system in the transfer lines results in additional phase advance constraints. It will be important to maintain some tuning range for the LHC commissioning phase and to accommodate possible further optics changes. We analyse the requirements, the constraints, the current status and options to enhance the optics flexibility.  
 
MPPE049 Sensitivity Study for Evaluating the Extracted Beam Parameters of the LLUMC Proton Therapy Synchrotron optics, proton, synchrotron, target 3046
 
  • G.H. Gillespie, W. Hill
    G.H. Gillespie Associates, Inc., Del Mar, California
  • G. Coutrakon, J. Hubbard, E. Sanders
    LLU/MC, Loma Linda, California
  The MINOS nonlinear constrained optimization program, working in concert with the beam optics code TRANSPORT, has been shown in recent work to provide a fast, efficient and reliable procedure for determining the parameters of the beam extracted from the LLUMC proton therapy synchrotron. MINOS and TRANSPORT work together as Modules of the Particle Beam Optics Laboratory (PBO Lab) software. The software was used to determine the parameters of the beam extracted from the synchrotron accelerator that best fit the extensive wire scanner profile data used to monitor the LLUMC proton therapy beamlines. In this paper additional constraints and optimizer variables are utilized with the procedure, in order to evaluate the sensitivity of the best fit extracted beam parameters to various assumptions. The methods used will be described and selected results from the study presented.  
 
MPPE057 Measurement of the Vertical Emittance and Beta Function at the PEP-II Interaction Point Using the BaBar Detector luminosity, storage-ring, positron, factory 3387
 
  • J.M. Thompson, A. Roodman
    SLAC, Menlo Park, California
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  Funding: U.S. Department of Energy.

We present measurements of the effective vertical emittance and IP beta function in the PEP-II Asymmetric B Factory. These beam parameters are extracted from fits to the longitudinal dependence of the luminosity and of the vertical luminous size, measured using e+ e- –> mu+ mu- events recorded in the Babar detector. The results are compared, for different sets of machine conditions, to accelerator-based measurements of the optical functions of the two beams.

 
 
MPPE068 Effects on Flat-Beam Generation from Space-Charge Force and Beamline Errors space-charge, quadrupole, gun, cathode 3774
 
  • Y.-E. S. Sun
    University of Chicago, Chicago, Illinois
  • K.-J. Kim
    ANL, Argonne, Illinois
  • P. Piot
    Fermilab, Batavia, Illinois
  The transformation of a round, angular-momentum-dominated electron beam into a flat beam using a skew-quadrupole channel has been developed theoretically in several papers and demonstrated experimentally at the Fermilab/NICADD Photoinjector Laboratory. In this paper, we address the impacts of space-charge force and beamline errors on the round-to-flat beam transformation. We discuss the physical process of angular momentum cancellation during the beam passage through the skew-quadrupole channel, present analytical and numerical studies of the linear and nonlinear space-charge forces, and evaluate the corresponding limits on the ratio of vertical-to-horizontal emittances. We also investigate the sensitivities of flat-beam emittances on several systematic factors such as errors on quadrupole strengths and alignments.  
 
MPPP038 Harmonic Cavity Performance for NSLS-II undulator, damping, synchrotron, brightness 2544
 
  • A. Blednykh, S. Krinsky, B. Podobedov, J. Rose, N.A. Towne, J.-M. Wang
    BNL, Upton, Long Island, New York
  NSLS-II is a 3 GeV ultra-high brightness storage ring that is planned to succeed the present NSLS rings at Brookhaven. Ultra-low emittance bunch combined with a short bunch length results in the Touschek lifetime of only a few hours, which strongly advocates including harmonic RF in the baseline design of NSLS-II. This paper describes the required harmonic RF parameters, trade-offs between the possible choices and the expected system performance, including the implications on lifetime and instabilities.  
 
MPPP041 Transverse Instability of a Rectangular Bunch impedance, synchrotron, space-charge, damping 2657
 
  • V. Balbekov
    Fermilab, Batavia, Illinois
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-76CH03000.

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

 
 
MPPT016 Beam Injection for the PF-AR with a Single Pulsed Quadrupole Magnet injection, quadrupole, kicker, dipole 1517
 
  • K. Harada, Y. Kobayashi, T. Mitsuhashi, T. Miyajima, S. Nagahashi, T. Obina, A. Ueda
    KEK, Ibaraki
  We develop the injection system for PF-AR (Photon Factory Advanced Ring for Pulsed X-ray) with single pulse quadrupole (PQ) magnet without pulse local bump of the stored beam with four dipole kickers. The pulse quadrupole magnet has the length of 30cm, the field gradient of 3T/m, half-sine-form pulse width of 2.4mSec, measured inductance of 1.8mH and the peak current of about 2000A. With this magnet, the amplitude of the injected beam can be reduced to about the half of that only with septum magnets and the reduced amplitude is almost the same as the case of the usual injection with the pulse bump of the stored beam. We installed PQ-magnet at the short straight section near the south symmetric point of PF-AR in this summer of 2004 and succeeded to inject beam to the storage ring during the machine study in autumn, 2004.  
 
MPPT034 Field Modelling for the CESR-c Superconducting Wiggler Magnets wiggler, damping, quadrupole, linear-collider 2336
 
  • J.A. Crittenden, A.A. Mikhailichenko, A. Temnykh
    Cornell University, Department of Physics, Ithaca, New York
  • E.N. Smith, K.W. Smolenski
    Cornell University, Ithaca, New York
  Funding: National Science Foundation.

Superconducting wiggler magnets for operation of the CESR electron-storage ring at energies as low as 1.5 \gev have been designed, built and installed in the years 2000 to 2004. Finite-element models of field quality have been developed, various sources of field errors investigated and compared to field measurements. Minimization algorithms providing accurate analytic representations of the wiggler fields have been established. We present quantitative descriptions of field modelling, of measured field quality and of the accuracy achieved in the analytic functions of the field.

 
 
MPPT058 Progress on the Focus Coils for the MICE Channel focusing, vacuum, coupling, power-supply 3417
 
  • M.A. Green
    LBNL, Berkeley, California
  • Y. Ivanyushenkov
    CCLRC/RAL, Chilton, Didcot, Oxon
  • W. Lau, R. Senanayake, S.Q. Yang
    OXFORDphysics, Oxford, Oxon
  Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC03-76SF00098.

This report describes the progress on the magnet part of the absorber focus coil module for the international Muon Ionization Cooling Experiment (MICE). MICE consists of two cells of a SFOFO cooling channel that is similar to that studied in the level 2 study of a neutrino factory. The MICE absorber focus coil module consists of a pair of superconducting solenoids, mounted on an aluminum mandrel. The coil package that is in its own vacuum vessel surrounds an absorber, which does the ionization cooling of the muons. Either a liquid or solid absorber is within a separate vacuum vessel that is within the warm bore of the superconducting magnet. The superconducting focus coils may either be run in the solenoid mode (with the two coils at the same polarity) or in the flip mode (with the coil at opposite polarity causing the field direction to flip within the magnet bore). The superconducting coils will be cooled using a pair of small 4 K coolers. This report discusses the progress on the MICE focusing magnets, the magnet cooling system and the magnet current supply system.

 
 
MPPT061 Ideal Wiggler wiggler, quadrupole, focusing, dipole 3511
 
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  Described is the wiggler with reduced nonlinear components for usage in damping ring of Linear Collider. Zigzag field dependence on longitudinal coordinate made by profiling of poles.  
 
MOPB002 High Intensity High Charge State ECR Ion Sources ion, ion-source, plasma, electron 179
 
  • D. Leitner, C.M. Lyneis
    LBNL, Berkeley, California
  Funding: This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. Department of Energy under Contract DE AC03-76SF00098.

The next-generation heavy ion beam accelerators such as the proposed Rare Isotope Accelerator (RIA), the Radioactive Ion Beam Factory at RIKEN, the GSI upgrade project, the LHC-upgrade, and IMP in Lanzhou require a great variety of high charge state ion beams with a magnitude higher beam intensity than currently achievable. High performance Electron Cyclotron Resonance (ECR) ion sources can provide the flexibility since they can routinely produce beams from hydrogen to uranium. Over the last three decades, ECR ion sources have continued improving the available ion beam intensities by increasing the magnetic fields and ECR heating frequencies to enhance the confinement and the plasma density. With advances in superconducting magnet technology, a new generation of high field superconducting sources is now emerging, designed to meet the requirements of these next generation accelerator projects. The talk will briefly review the field of high performance ECR ion sources and the latest developments for high intensity ion beam production. The currently most advanced next-generation superconducting source ECR ion source VENUS will be described in more detail.

 
 
MOPB003 Progress with the 2Q-LEBT Facility for the RIA Project ion, ion-source, rfq, simulation 253
 
  • N. Vinogradov, V.N. Aseev, M.R.L. Kern, P.N. Ostroumov, R.C. Pardo, R.H. Scott
    ANL, Argonne, Illinois
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38.

The Rare Isotope Accelerator (RIA) facility utilizes the concept of simultaneous acceleration of two charge states from the ion source. We are building a prototype two charge-state (2Q) injector of the RIA Driver Linac, which includes an ECR ion source originally built by Berkeley Ion Equipment Corporation, a LEBT and one-segment of the prototype RFQ. The reassembly and commissioning of the ECR source has been completed. During the commissioning process we modified and replaced several major components of the BIE-100 to increase the source performance. A new diagnostic station has been designed and built for accurate measurements of the output beam emittance. The paper will discuss detailed beam dynamics studies together with extensive emittance measurements of various ion beams. The status of the design and fabrication of 100 kV high voltage platform, achromatic bending system, multi-harmonic buncher, and a full power 57.5 MHz RFQ segment will be presented.

 
 
MOPB006 Frontiers of RF Photoinjectors laser, gun, electron, cathode 530
 
  • M. Ferrario
    INFN/LNF, Frascati (Roma)
  New ideas have been recently proposed to achieve ultra-high brightness electron beams, as particularly needed in SASE-FEL experiments, and to produce flat beams, as required in linear colliders. Low emittance schemes already foreseen for split normal conducting photoinjectors have been applied to the superconducting case in order to produce high peak and high average beam brightness. RF compressor techniques have been partially confirmed by experimental results and more compact RF photoinjector designs including compression scheme are under development. Research and experiments in the flat beam production from a photoinjector as a possible alternative to damping rings are in progress. An overview of recent advancements and future perspectives in photoinjector beam physics is reported in this talk.  
 
MOPB007 Future Directions in Electron Sources cathode, electron, focusing, gun 563
 
  • J.W. Lewellen
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

The emittance-compensated rf photoinjector is in the process of evolving from an experiment in and of itself, to a laboratory instrument, to a workhorse component of large user facilities such as next-generation light sources. In recent years the performance achieved by the standard p-mode design has approached the levels predicted by theory and experiment. The basic design has been scaled from X-band down to less than 1 GHz in terms of operating frequency, and superconducting designs are presently undergoing initial testing at various locations. The requirements for linac-based light sources will require at least one order of magnitude improvement in beam quality; other applications, such as electron microscopes or high-energy electron lithography, require still greater improvements. The migration towards fully superconducting accelerators provides some additional design challenges. This paper briefly presents requirements for some future applications, and presents four new approaches to extending injector performance: the diamond-emitter photocathode, the planar focusing cathode, the magnetic-mode emittance compensation technique, and the field-emission-gated cathode.

 
 
MOPB008 Temporal E-Beam Shaping in an S-Band Accelerator laser, electron, linac, diagnostics 642
 
  • H. Loos, D. Dowell, A. Gilevich, C. Limborg-Deprey
    SLAC, Menlo Park, California
  • M. Boscolo, M. Ferrario, M. Petrarca, C. Vicario
    INFN/LNF, Frascati (Roma)
  • J.B. Murphy, B. Sheehy, Y. Shen, T. Tsang, X.J. Wang, Z. Wu
    BNL, Upton, Long Island, New York
  • L. Serafini
    INFN-Milano, Milano
  Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contracts DE-AC02-98CH10886 and DE-AC03-76SF00515.

New short-wavelength SASE light sources will require very bright electron beams, brighter in some cases than is now possible. One method for improving brightness involves the careful shaping of the electron bunch to control the degrading effects of its space charge forces. We study this experimentally in an S-band system, by using an acousto-optical programmable dispersive filter to shape the photocathode laser pulse that drives the RF photoinjector. We report on the efficacy of shaping from the IR through the UV, and the effects of shaping on the electron beam dynamics.

 
 
MOPB011 Axial RF Power Input in Photocathode Electron Guns cathode, gun, electron, superconducting-RF 743
 
  • D. Janssen
    FZR, Dresden
  • H. Bluem, A.M.M. Todd
    AES, Princeton, New Jersey
  • V. Volkov
    BINP SB RAS, Novosibirsk
  We discuss the coaxial power input in normal and superconducting RF (SRF)photoinjector cavities. Upstream coaxial power input has been previously used at the PITZ facility where the output beam tube is an intrinsic part of the coaxial transmission line into the gun. In this paper, we describe coaxial coupling from the cathode side of the gun. For normal conducting RF guns, in addition to the advantage from symmetric coupling, an emittance compensation solenoid can now be positioned close to the gun cavity to deliver optimal transverse emittance. Beam dynamics calculations demonstrate 0.8 mm-mrad at 1 nC in X-band. For an SRF gun, we present a design for coaxial input around the cathode using a superconducting coupling cell. This cell matches the external quality factor of the gun for different beam powers and there is no RF loss associated with the axial gap of the cathode. The heat input into the coaxial feed and the surface field of the coupler are discussed. For a 1.3 GHz half-cell gun cavity with stored energy of 6.6 J, a 2.5 MeV electron beam can be delivered with a peak accelerating field of 50 MV/m. At 10 mA,the external Q is 2.1 x 106 and the coaxial line power loss that must be cooled is 28 W.  
 
TPAE028 Beam Dynamics Studies for a Laser Acceleration Experiment linac, gun, space-charge, laser 2024
 
  • J.E. Spencer, E.R. Colby, R.J. Noble, D.T. Palmer, R. Siemann
    SLAC, Menlo Park, California
  Funding: Support of this work was under U.S. Dept. of Energy contract DE-AC02-76SF00515.

The NLC Test Accelerator at SLAC was built to address various beam dynamics issues for the Next Linear Collider. An S-Band RF gun, originally proposed for the NLCTA, is being installed together with a large-angle extraction line at 60 MeV. This is followed by a matching section, final focus and buncher for the laser acceleration experiment, E163. The laser-electron interaction area is followed by a broad range, high resolution spectrometer (HES) for electron bunch analysis. The RF gun is discussed in another paper. We discuss only the beam dynamics and high resolution analysis system at 6 MeV based on using Parmela and high-order Transport for bunch charges from 50 pC to 1 nC. Beyond the diagnostics, this system uses the emittance compensating solenoids and a low energy, high resolution spectrometer (LES) to help tune for best operating point and match to the linac. Optical symmetries in the design of the 25.5° extraction line provide 1:1 phase space transfer without linear dispersion or use of sextupoles for a large, 6D phase space volume and range of input conditions. Tolerances and tuning sensitivities (knobs) for certain parts of the system are discussed.

 
 
TPAE039 The Effects of Ion Motion in Very Intense Beam-Driven Plasma Wakefield Accelerators ion, plasma, electron, collider 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, collider 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.

 
 
TPAE042 Beam Matching to a Plasma Wake Field Accelerator Using a Ramped Density Profile at the Plasma Boundary plasma, synchrotron, focusing, ion 2702
 
  • K.A. Marsh, C.E. Clayton, C. Huang, D.K. Johnson, C. Joshi, W. Lu, W.B. Mori, M. Zhou
    UCLA, Los Angeles, California
  • C.D. Barnes, F.-J. Decker, M.J. Hogan, R.H. Iverson, P. Krejcik, C.L. O'Connell, R. Siemann, D.R. Walz
    SLAC, Menlo Park, California
  • S. Deng, T.C. Katsouleas, P. Muggli, E. Oz
    USC, Los Angeles, California
  Funding: DOE Grant No. DE-FG03-92ER40727.

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

 
 
TPAE067 Femtosecond Electron Diffraction and its Application for Beam Characterization at the PAL electron, laser, gun, space-charge 3721
 
  • D. Xiang
    TUB, Beijing
  • H. Ihee
    KAIST, Daejeon
  • I.S. Ko, S.J. Park
    PAL, Pohang, Kyungbuk
  • X.J. Wang
    BNL, Upton, Long Island, New York
  Electron diffraction is widely used in electron microscopy to obtain ultrahigh magnification factor, or crystallography to determine the internal structure of the molecule. High energy electron (MeV) has been used to probe the solid state thick sample, now being explored for femto-second electron diffraction (FED) to determine the transient structure of the molecule. We are proposing to perform FED using a photocathode RF gun at the Pohang Accelerator Laboratory (PAL), and develop an advanced electron beam diagnostic tool based on the electron diffraction. In this paper we will study how the diffraction pattern can be used to extract the information on the beam’s divergence. With a well-known sample, such as aluminum foil, whose internal structure is predetermined, the diffraction pattern for both single electron and the electron beam with a given divergence distribution can be calculated. Our proposed technique shows great potential of electron diffraction in beam divergence characterization. An experiment to verify the practicality of this method is under preparation and will be carried out at the proposed high brightness R&D facility at the PAL) in the near future.  
 
TPAP018 Optics Studies of the LHC Beam Transfer Line TI8 optics, quadrupole, coupling, extraction 1578
 
  • J. Wenninger, G. Arduini, B. Goddard, D. Jacquet, V. Kain, M. Lamont, V. Mertens, J.A. Uythoven
    CERN, Geneva
  • Y.-C. Chao
    Jefferson Lab, Newport News, Virginia
  The optics of the newly commissioned LHC beam transfer line TI 8 was studied with beam trajectories, dispersion and profile measurements. Steering magnet response measurements were used to analyze the quality of the steering magnets and of the beam position monitors. A simultaneous fit of the quadrupole strengths was used to search for setting or calibration errors. Residual coupling between the planes was evaluated using high statistics samples of trajectories. Initial conditions for the optics at the entrance of the transfer line were reconstructed from beam profile measurements with Optical Transition Radiation monitors. The paper presents the various analysis methods and their errors. The expected emittance growth arising from optical mismatch into the LHC is evaluated.  
 
TPAP021 A New Technique for Making Bright Proton Bunches using Barrier RF Systems proton, simulation, collider, 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.

 
 
TPAP026 Improving the Tevatron Collision Helix antiproton, luminosity, proton, beam-beam-effects 1931
 
  • R. Moore, Y. Alexahin, J.A. Johnstone, T. Sen
    Fermilab, Batavia, Illinois
  In the Tevatron, protons and pbars circulate in a single beam pipe, so electrostatic separators are used to create helical orbits that separate the two beams except at the two interaction points (IP). Increasing the separation outside of the IPs is desirable in order to decrease long range beam-beam effects during high energy physics (HEP) stores. We can increase separation by running the separators at higher gradients or by installing additional separators. We are pursuing both strategies in parallel. Here, we describe Tevatron operation with higher separator gradients and with new separators installed during a recent shutdown. We also describe possible future improvements.  
 
TPAP031 Simulations of an Acceleration Scheme for Producing High Intensity and Low Emittance Antiproton Beam for Fermilab Collider Operation beam-loading, acceleration, simulation, antiproton 2164
 
  • V. Wu, C.M. Bhat, J.A. MacLachlan
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association, Inc. for the U.S. Department of Energy under contract DE-AC02-76CH03000.

During Fermilab collider operation, the Main Injector (MI) provides high intensity and low emittance proton and antiproton beams for the Tevatron. The present coalescing scheme for antiprotons in the Main Injector yields about a factor of two increase in the longitudinal emittance and a factor of 5% to 20% decrease in intensity before injection to the Tevatron. In order to maximize the integrated luminosity delivered to the collider experiments, it is important to minimize the emittance growth and maximize the intensity of the MI beam. To this end, a new scheme* using a combination of 2.5 MHz and 53 MHz accelerations has been developed and tested. This paper describes the full simulation of the new acceleration scheme, taking account of space charge, 2.5 MHz and 53 MHz beam loading, and the effect of residual 53 MHz rf voltage during 2.5 MHz acceleration and rf manipulations. The simulations show the longitudinal emittance growth at the 10% level with no beam loss. The experimental test of the new scheme is reported in another PAC'05 paper.

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

 
 
TPAP032 Beam-beam Effects in the Tevatron Run II antiproton, proton, luminosity, injection 2245
 
  • V.D. Shiltsev, Y. Alexahin, V. Lebedev, P. Lebrun, R. Moore, T. Sen, A. Valishev, X. Zhang
    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 Tevatron in Collider Run II (2001-present) is operating with many times higher beam intensities and luminosities than in previous Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance at upgraded beam parameters and luminosity and discuss possible improvements.

 
 
TPAP033 Tevatron Admittance Measurement proton, antiproton, kicker, betatron 2306
 
  • X. Zhang, V.D. Shiltsev, C.-Y. Tan
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy.

We measured the Tevatron Beam Acceptance by the method of exciting the beam emittance growth with the beam tickling system with noise. The noise power was about 3Watt with 100Hz bandwidth and centered either in horizontal betatron frequency or vertical betatron frequency. We were able to blow the beam emittance fast while under control. From the point the beam emittance stop growing, we measured the beam acceptance of the Tevatron.

 
 
TPAP037 Monte Carlo of Tevatron Operations, Including the Recycler antiproton, luminosity, proton, electron 2479
 
  • E.S. McCrory
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

A Monte Carlo model, which was originally developed for "Run I" of the Tevatron Collider, has been enhanced in many ways, most notably, to incorporate the effect of the Recycler Ring. This model takes into account reasonable random fluctuations in the performance of the Collider, and normal interruptions in operation of each accelerator due to downtime. Optimization of the integrated luminosity delivered to the experiments is based on when to end the store and how to deal with the anitprotons. Preliminary results show that a 20% gain in integrated luminosity in the Collider results from using the Recycler for one-third of the anitprotons in each store. As electron cooling becomes operative in the Recycler, Collider performance improves by as much as a factor of two.

 
 
TPAP038 Characterizing Luminosity Evolution in the Tevatron luminosity, proton, beam-beam-effects, antiproton 2536
 
  • E.S. McCrory, V.D. Shiltsev
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

We derive an approximate form of a luminosity evolution in a high intensity hadron collider taking into account the most important phenomena of intrabeam scattering (IBS), beam burn-up due to luminosity and beam-beam effects. It is well known that an exponential decay does not describe luminosity evolution very well unless the lifetime is allowed to vary with time. However, a "1/time" evolution, which this derivation shows is a good approximation, fits data from the Tevatron well.

 
 
TPAP043 Electron Cooling of RHIC electron, ion, linac, simulation 2741
 
  • I. Ben-Zvi, D.S. Barton, D.B. Beavis, M. Blaskiewicz, J.M. Brennan, A. Burrill, R. Calaga, P. Cameron, X.Y. Chang, R. Connolly, Yu.I. Eidelman, A.V. Fedotov, W. Fischer, D.M. Gassner, H. Hahn, M. Harrison, A. Hershcovitch, H.-C. Hseuh, A.K. Jain, P.D.J. Johnson, D. Kayran, J. Kewisch, R.F. Lambiase, V. Litvinenko, W.W. MacKay, G.J. Mahler, N. Malitsky, G.T. McIntyre, W. Meng, K.A.M. Mirabella, C. Montag, T.C.N. Nehring, T. Nicoletti, B. Oerter, G. Parzen, D. Pate, J. Rank, T. Rao, T. Roser, T. Russo, J. Scaduto, K. Smith, D. Trbojevic, G. Wang, J. Wei, N.W.W. Williams, K.-C. Wu, V. Yakimenko, A. Zaltsman, Y. Zhao
    BNL, Upton, Long Island, New York
  • D.T. Abell, D.L. Bruhwiler
    Tech-X, Boulder, Colorado
  • H. Bluem, A. Burger, M.D. Cole, A.J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A.M.M. Todd
    AES, Princeton, New Jersey
  • A.V. Burov, S. Nagaitsev
    Fermilab, Batavia, Illinois
  • J.R. Delayen, Y.S. Derbenev, L. W. Funk, P. Kneisel, L. Merminga, H.L. Phillips, J.P. Preble
    Jefferson Lab, Newport News, Virginia
  • I. Koop, V.V. Parkhomchuk, Y.M. Shatunov, A.N. Skrinsky
    BINP SB RAS, Novosibirsk
  • I.N. Meshkov, A.O. Sidorin, A.V. Smirnov, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  • J.S. Sekutowicz
    DESY, Hamburg
  We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV. A Zeroth Order Design Report is in an advanced draft state, and can be found on the web at http://www.agsrhichome.bnl.gov/eCool/.

Under contract with the U.S. Department of Energy, Contract Number DE-AC02-98CH10886.

 
 
TPAP047 Killing the Electron Cloud Effect in the LHC Arcs electron, dipole, vacuum, proton 2971
 
  • P.M. McIntyre, A. Sattarov
    Texas A&M University, College Station, Texas
  A getter/electrode assembly has been devised to suppress the regeneration mechanism of the electron cloud effect in the arc dipoles of LHC. The assembly consists of a copper foil electrode, supported through an insulating layer on a stainless steel skid, which would rest upon the flat bottom of the beam screen. The electrode is coated with NEG to provide effective pumping of all non-inert gases from the vacuum. Pumping should be enhanced by electron bombardment. By biasing the electrode ~+100 V secondary electrons produced on the surface would be fully re-absorbed, killing the regeneration mechanism. The NEG surface can be regenerated by passing a current through the electrode to heat it to ~240 C. The heat transfer (radiant + conductive) to the beam screen during regeneration is estimated ~10 W/m, within limits to maintain the beam screen at nominal 20 K temperature during regeneration. The entire assembly has been designed so that installation does not require modification of any hardware currently being built for the LHC arcs. The electrode assembly would occupy 1 mm in the vertical aperture of the beam screen.  
 
TPAP054 Helium Flow Induced Orbit Jitter at RHIC monitoring, heavy-ion, injection, quadrupole 3262
 
  • C. Montag, P. He, L. Jia, T. Nicoletti, T. Satogata, J. Schmalzle, T. Tallerico
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the US Department of Energy.

Horizontal beam orbit jitter at frequencies around 10 Hz has been observed at RHIC for several years. The distinct frequencies of this jitter have been found at superconducting low-beta qudrupole triplets around the ring, where they coincide with mechanical modes of the cold masses. Recently, we have identified liquid helium flow as the driving force of these oscillations.

 
 
TPAP055 Fast IR orbit feedback at RHIC feedback, power-supply, coupling, luminosity 3298
 
  • C. Montag, A. Marusic, R.J. Michnoff, T. Roser, T. Satogata, C. Schultheiss
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the US Department of Energy

Mechanical low-beta triplet vibrations lead to horizontal jitter of RHIC beams at frequencies around 10 Hz. The resulting beam offsets at the interaction points are considered detrimental to RHIC luminosity performance. To stabilize beam orbits at the interaction points, installation of a fast orbit feedback is foreseen. A prototype of this system is being developed and tested. Recent results are presented.

 
 
TPAP056 Electron Beam Stability Requirements for Linac-Ring Electron-Ion Colliders electron, simulation, ion, luminosity 3363
 
  • C. Montag
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

In recent years, linac-ring electron-ion colliders have been proposed at a number of laboratories around the world. While the linac-ring approach overcomes the beam-beam tuneshift limitation on the electron beam, it also introduces noise into the ion beam, via the beam-beam interaction with electron bunches of slightly fluctuating intensity and transverse size. The effect of these fluctuations is studied using a linearized model of the beam-beam interaction. Upper limits for the rms jitter amplitudes of electron beam parameters for various linac-ring electron-ion colliders are presented.

 
 
TPAP057 Beam-Beam Simulations for the eRHIC Electron Ring electron, luminosity, simulation, resonance 3399
 
  • C. Montag
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

To study collisions between polarized electrons and heavy ions or polarized protons at high energy, adding a 10 GeV electron storage ring to the existing RHIC facility is currently under consideration. To achieve high luminosities, vertical beam-beam tuneshift parameters of 0.08 are required for the electron beam. Simulation studies are being performed to study the feasibility of these high tuneshift parameters and to explore the potential for even higher tuneshifts. Recent results of these studies are presented.

 
 
TPAP058 Beam-Beam Simulations for Double-Gaussian Beams simulation, luminosity, proton, electron 3405
 
  • C. Montag, I. Ben-Zvi, V. Litvinenko, N. Malitsky
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two Gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-Gaussian beams. Here we report the effect of low-frequency random tune modulations on diffusion in double-Gaussian beams and compare the effects to those in beam-beam interactions with regular Gaussian beams and identical tuneshift parameters.

 
 
TPAT001 An Ultra-Bright Pulsed Electron Beam with Low Longitudinal Emittance electron, laser, brightness, ion 770
 
  • M.S. Zolotorev, E. D. Commins, P. Denes, Z. Hussain, G.V. Lebedev, S.M. Lidia, D. Robin, F. Sannibale, R.W. Schoenlein, R. A. Vogel, W. Wan
    LBNL, Berkeley, California
  • S.A. Heifets
    SLAC, Menlo Park, California
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

We describe a novel scheme for an electron source in the 10 - 100 eV range with the capability of approaching the brightness quantum-limit and of lowering the effective temperature of the electrons orders of magnitude with respect to existing sources. Such a device can open the way for a wide range of novel applications that utilize angstrom-scale spatial resolution and ?eV-scale energy resolution. Possible examples include electron microscopy, electron holography, and investigations of dynamics on a picosecond time scale using pump-probe techniques. In this paper we describe the concepts for such a source including a complete and consistent set of parameters for the construction of a real device based on the presented scheme.

 
 
TPAT003 Cold-Fluid Equilibrium of a Large-Aspect-Ratio Ellipse-Shaped Charged-Particle Beam in a Non-Axisymmetric Periodic Permanent Magnet Focusing Field simulation, focusing, vacuum, permanent-magnet 853
 
  • J.Z. Zhou, R. Bhatt, C. Chen
    MIT/PSFC, Cambridge, Massachusetts
  Funding: U.S. DOE, Grant: No. DE-FG02-95ER40919,Grant No. DE-FG02-01ER54662, Air Force Office of Scientific Research, Grant No. F49620-03-1-0230, and the MIT Deshpande Center for Technological Innovation.

A new class of equilibrium is discovered for a large-aspect-ratio ellipse-shaped charged-particle beam in a non-axisymmetric periodic permanent magnet focusing field. A paraxial cold-fluid model is employed to derive the equilibrium flow properties and generalized envelope equations with negligibly small emittance. A periodic beam equilibrium solution is obtained numerically from the generalized envelope equations. It is shown that the beam edges are well confined in both transverse directions, and that the equilibrium beam exhibits a small-angle periodic wobble as it propagates. A two-dimensional particle-in-cell (PIC) code, PFB2D, is used to verify the theoretical predictions in the paraxial limit, and to establish validity under non-paraxial situations and the influence of the conductor walls of the beam tunnel.

 
 
TPAT004 Strongly Asymmetric Beams at the University of Maryland Electron Ring (UMER) focusing, electron, quadrupole, diagnostics 892
 
  • S. Bernal, R.A. Kishek, P.G. O'Shea, B. Quinn, M. Walter
    IREAP, College Park, Maryland
  • M. Reiser
    University Maryland, College Park, Maryland
  Funding: This work is funded by U.S. Dept. of Energy under grants DE-FG02-94ER40855 and DE-FG02-92ER54178.

The standard operation of the University of Maryland electron ring employs symmetric strong focusing with magnetic quadrupoles, i.e., a FODO scheme whereby the zero-current betatron phase advances per period in the two transverse planes are equal or nearly so. Asymmetric focusing, on the other hand, employs quadrupoles with different strengths in a FODO cell. Typically, a small focusing asymmetry is implemented in most accelerators to set the operating point (horizontal and vertical zero-current tunes) in order to avoid resonances and/or compensate for edge focusing of bend magnets. Extreme asymmetry, however, is rarely, if at all, used. We review the motivation and theory of beam transport with general focusing asymmetry. We also present results of preliminary experiments and simulations with highly asymmetric focusing of a space-charge dominated electron beam in UMER.

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

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

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

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

 
 
TPAT019 Discussions on the Cancellation Effect on a Curved Orbit transverse-dynamics, simulation, space-charge, storage-ring 1631
 
  • R. Li, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by DOE Contract DE-AC05-84ER40150.

The canonical formulation and the cancellation effect for bunch dynamics under collective interaction on a curved orbit were presented in Ref. [*]. Some possible controversial representations of the cancellation effect were later addressed by Geloni et al.** In this study, we discuss all the points raised in Ref. [**] based on our canonical treatment, and show how these points can be perceived from the view point of the cancellation picture.

*R. Li and Ya. S. Derbenev, Jefferson Laboratory Report No. LJAB-TN-02-054, 2003. **G. Geloni et al., DESY Report No. DESY 03-165, 2003.

 
 
TPAT030 Transverse Beam Matching Application for SNS SNS, linac, optics, quadrupole 2143
 
  • C. Chu, V.V. Danilov, D.-O. Jeon, M.A. Plum
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

An automated transverse beam matching application has been developed for the Spallation Neutron Source (SNS) beam transport lines. The application is written within the XAL Java framework and the matching algorithm is based on the simplex optimization method. Other functionalities, such as emittance calculated from profile monitor measurements (adopted from a LANL Fortran code), profile monitor display, and XAL on-line model calculation, are also provided by the application. Test results obtained during the SNS warm linac commissioning will be reported. A comparison between the emittances obtained from this application and an independent Trace-3D routine will also be shown.

 
 
TPAT033 Experimental Characterizations of 4-D Transverse Phase-Space of a Compressed Beam linac, electron, space-charge, focusing 2263
 
  • F. Zhou, R.B. Agustsson, G. Andonian, D. Cline, A.Y. Murokh, J.B. Rosenzweig
    UCLA, Los Angeles, California
  • I. Ben-Zvi, V. Yakimenko
    BNL, Upton, Long Island, New York
  Funding: Work supported by U.S. DOE.

Coherent synchrotron radiation can significantly distort beam phase spaces in longitudinal direction and bending plane through a bunch compressor. A tomography technique is used to reconstruct transverse phase space of electron beam. Transverse 4-D phase spaces are systematically measured at UCLA/ATF compressor and their characteristics with different bunch compression conditions are analyzed.

 
 
TPAT034 Manipulations of Double Electron Beams within One RF Period for Seeded SM-LWFA Experiment laser, electron, plasma, linac 2312
 
  • F. Zhou, D. Cline
    UCLA, Los Angeles, California
  • M. Babzien, V. Yakimenko
    BNL, Upton, Long Island, New York
  • W.D. Kimura
    STI, Washington
  Funding: Work supported by U.S. DOE.

Although seeded SM-LWFA only requires one electron beam to initiate the laser wakefield, it would be highly desirable to have a second electron beam traveling after the first one to probe the accelerated electrons. To create and preserve significant amount of wakefield in the STELLA SM-LWFA experiment, the first e-beam needs to be tiny (<40 microns FWHM) in size and short in length within the plasma. To probe the wakefield which is damped within 10 ps for certain plasma density, the separation between the first and second beams needs to be within one RF period and the second e-beam must have smaller energy spread and smaller size. Design of double beams in one RF period to meet the strict requirements and the preliminary beam study at BNL-ATF facility are presented. The scheme of double beams with ATF bunch compressor is also discussed.

 
 
TPAT035 Coherent Synchrotron Radiation from an Electron Beam in a Curved Waveguide electron, radiation, simulation, synchrotron 2390
 
  • D.R. Gillingham, T. M. Antonsen, P.G. O'Shea
    IREAP, College Park, Maryland
  Funding: Research supported by the office of Naval Research and the Joint Technology Office.

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

 
 
TPAT038 Chaos in Time-Dependent Space-Charge Potentials space-charge, linac, proton 2515
 
  • G.T. Betzel, C.L. Bohn, I.V. Sideris
    Northern Illinois University, DeKalb, Illinois
  We consider a spherically symmetric, homologously breathing, space-charge-dominated beam bunch in the spirit of the particle-core model. The question we ask is: How does the time dependence influence the population of chaotic orbits? The static beam has zero chaotic orbits; the equation of particle motion is integrable up to quadrature. This is generally not true once the bunch is set into oscillation. We quantify the population of chaotic orbits as a function of space charge and oscillation amplitude (mismatch). We also apply a newly developed measure of chaos, one that distinguishes between regular, sticky, and wildly chaotic orbits, to characterize the phase space in detail. We then introduce colored noise into the system and show how its presence modifies the dynamics. One finding is that, despite the presence of a sizeable population of chaotic orbits, halo formation in the homologously breathing beam is much less prevalent than in an envelope-matched counterpart wherein an internal collective mode is excited.  
 
TPAT042 Progress on a Vlasov Treatment of Coherent Synchrotron Radiation from Arbitrary Planar Orbits synchrotron, synchrotron-radiation, radiation, lattice 2699
 
  • G. Bassi, J.A. Ellison
    UNM, Albuquerque, New Mexico
  • R.L. Warnock
    SLAC, Menlo Park, California
  Funding: Support from DOE grants DE-AC02-76SF00515 and DE-FG02-99ER1104 is gratefully acknowledged.

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

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

 
 
TPAT046 Nonlinear Stability of Intense Mismatched Beams in a Uniform Focusing Field focusing, space-charge, coupling, beam-losses 2941
 
  • R. Pakter, F.B. Rizzato, W. Simeoni
    IF-UFRGS, Porto Alegre
  Funding: Work supported by Brazilian agencies CNPq, CAPES, and FAPERGS.

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

 
 
TPAT047 A Space Charge Compensation Study of Low Energy Hydrogen Ion Beams space-charge, ion, simulation, electron 2947
 
  • A. BenIsmail, R. Duperrier, D. Uriot
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • N. Pichoff
    CEA/DAM, Bruyères-le-Châtel
  Funding: Work supported by the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).

High-power accelerators are being studied for several projects including accelerator driven neutron or neutrino sources. The low energy part of these facilities has to be carefully optimized to match the beam requirements of the higher energy parts. The complexity of high intensity beam dynamics in the low energy line is essentially due to the non-linear space charge effects. The PIC code CARTAGO* has been developed in order to simulate the beam transport at low energy including the temporal evolution effects of the space charge compensation. This paper relates the structure and the numerical methods of a 2D (r,z) new version of the code. The effects of the longitudinal space charge, the image charge and external 2D (r,z) magnetic field were included. The results of H+ and H- beam transports using solenoid lenses are discussed. Space charge compensation degrees are given for each studied cases.

*A. Ben Ismail et al., in Space Charge Compensation in Low Energy Proton Beams, proceeding of the International Linear Accelerator Conference, Lübeck, 2004.

 
 
TPAT050 Beam Dynamics Design of the L3BT for J-PARC injection, space-charge, linac, simulation 3091
 
  • T. Ohkawa
    JAERI, Ibaraki-ken
  • M. Ikegami
    KEK, Ibaraki
  L3BT is beam transportation line from the linac to the 3-GeV RCS which is the part of the accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC.In this paper, especially results of the beam simulation of the injection section of the L3BT are presented. And the matching of rms envelopes and dispersion function for space charge dominated beams are also discussed.  
 
TPAT060 Overview of the Synergia 3-D Multi-Particle Dynamics Modeling Framework simulation, booster, space-charge, injection 3490
 
  • P. Spentzouris, J.F. Amundson
    Fermilab, Batavia, Illinois
  • D.R. Dechow
    Tech-X, Boulder, Colorado
  Funding: Scientific Discovery through Advanced Computing project, "Advanced Computing for 21st Century Accelerator Science and Technology," U.S. DOE/SC Office of High Energy Physics and the Office of Advanced Scientific Computing Research.

High precision modeling of space-charge effects is essential for designing future accelerators as well as optimizing the performance of existing machines. Synergia is a high-fidelity parallel beam dynamics simulation package with fully three dimensional space-charge capabilities and a higher-order optics implementation. We describe the Synergia framework and model benchmarks we obtained by comparing to semi-analytic results and other codes. We also present Synergia simulations of the Fermilab Booster accelerator and comparisons with experiment.

 
 
TPAT061 Accurate Iterative Analysis of the K-V Equations quadrupole, lattice, simulation, focusing 3535
 
  • O.A. Anderson
    LBNL, Berkeley, California
  Funding: Supported in part by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

Previous solutions of the K-V equations have either yielded poor accuracy or have been complex and difficult to follow. We describe a new approach, simple in concept, easy to use, with accuracy substantially improved over previous treatments. The results are given in the same form as the smooth approximation but include a few correction terms obtained from the field gradient integrated along the axis of a quadrupole cell. The input quantities–quadrupole field, beam current, and emittance–yield the average beam radius, the maximum envelope excursion, and the depressed and undepressed tunes. For all values of the input parameters, the results are much closer to the exact values from simulations than are results from the smooth approximation. For example, with the parameters adjusted for an exact phase advance of 83.4 degrees and 50% tune depression, both tunes are in error by less than 0.5%–over 22 times better than the smooth approximation. The error in maximum radius is 0.04%, improved by a factor of 80. The new method and its application to a wide range of cases will be presented.

 
 
TPAT062 Uncorrelated Energy Spread and Longitudinal Emittance for a Photoinjector Beam space-charge, gun, electron, simulation 3570
 
  • Z. Huang, D. Dowell, P. Emma, C. Limborg-Deprey, G.V. Stupakov, J. Wu
    SLAC, Menlo Park, California
  Longitudinal phase space properties of a photoinjector beam are important in many areas of high-brightness beam applications such as bunch compression, transverse-to-longitudinal emittance exchange, and high-gain free-electron lasers. In this paper, we discuss both the rf and the space charge contributions to the uncorrelated energy spread of the beam generated from a laser-driven rf gun. We compare analytical expressions for the uncorrelated energy spread and the longitudinal emittance with numerical simulations and recent experimental results.  
 
TPAT066 Significance of Space Charge and the Earth Magnetic Field on the Dispersive Characteristics of a Low Energy Electron Beam space-charge, simulation, lattice, electron 3691
 
  • R.A. Kishek, G. Bai, S. Bernal, T.F. Godlove, I. Haber, P.G. O'Shea, B. Quinn, C. Tobin, M. Walter
    IREAP, College Park, Maryland
  • M. Reiser
    University Maryland, College Park, Maryland
  Funding: This work is funded by U.S. Dept. of Energy grant numbers DE-FG02-94ER40855 and DE-FG02-92ER54178.

The combination of energy spread and space charge provides a rich domain for interesting beam dynamics that are currently not well understood. The University of Maryland Electron Ring (UMER) [1] is a small scaled ring designed to probe the little-known regions of higher beam intensities using low-energy electrons. As such, design, commissioning and operation of UMER present many challenges, some quite novel. For example the UMER beam energy of 10 keV makes the beam very sensitive to the Earth magnetic field, which we can fortunately use to assist in bending the beam. This paper presents a systematic simulation study of the interaction of space charge and energy spread, with and without the earth magnetic field.

*"Commissioning of the University of Maryland Electron Ring (UMER)," S. Bernal, et al., this conference.

 
 
TPAT078 Coherent Beam-Beam Modes in the CERN Large Hadron Collider (LHC) for Multiple Bunches, Different Collisions Schemes and Machine Symmetries simulation, damping, coupling, dipole 4030
 
  • T. Pieloni, W. Herr
    CERN, Geneva
  In the LHC almost 3000 bunches in each beam will collide near several experimental regions and experience head-on as well as long range beam-beam interactions. In addition to single bunch phenomena, coherent bunch oscillations can be excited. Due to the irregular filling pattern and the unsymmetric collision scheme, a large number of possible modes must be expected, with possible consequences for beam measurements. To study these effects, a simulation program was developped which allows to evaluate the interaction of many bunches. It is flexible enough to easily implement any possible bunch configuration and collision schedule and also to study the effect of machine imperfections such as optical asymmetries. First results will be presented and future developments are discussed.  
 
TPAT079 Importance of the Linear Coupling and Multipole Compensation of Long-Range Beam-Beam Interactions In Tevatron multipole, coupling, beam-beam-effects, simulation 4039
 
  • J. Shi, B. Anhalt
    KU, Lawrence, Kansas
  Funding: The US Department of Energy under Grant No. DE-FG02-04ER41288.

In Tevatron, serious long-range beam-beam effects are due to many parasitic collisions that are distributed around the ring. Because of this non-localized nature of long-range beam-beam interactions, the multipole compensation with one-turn or sectional maps aims a global compensation of long-range beam-beam interactions. Since nonlinear beam dynamics in a storage ring can usually be described by a one-turn map that contains all global information of system nonlinearities, by minimizing nonlinear terms of the maps order-by-order with a few groups of multipole correctors, one could reduce the nonlinearity globally. Since a large beam separation is typical at parasitic points, in the phase-space region that is relevant to the beam, long-range beam-beam interactions can be expanded into a Taylor series around the beam separation and be included into the one-turn map for the global compensation. To examine the effect of this multipole compensation scheme, the emittance growth of both p and pbar beam in Tevatron were studied with a beam-beam simulation. The result showed that the multipole compensation can significantly reduces the emittance growth of the pbar beam due to long-range beam-beam interactions.

 
 
TPAT081 Observation of Electron-Ion Effects at RHIC Transition beam-losses, electron, vacuum, octupole 4087
 
  • J. Wei, M. Bai, M. Blaskiewicz, P. Cameron, R. Connolly, A. Della Penna, W. Fischer, H. Huang, U. Iriso, R.C. Lee, R.J. Michnoff, V. Ptitsyn, T. Roser, T. Satogata, S. Tepikian, L. Wang, S.Y. Zhang
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

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

 
 
TPAT082 Phonon Modes and the Maintenance Condition of a Crystalline Beam lattice, resonance, focusing, coupling 4111
 
  • J. Wei
    BNL, Upton, Long Island, New York
  • H. Enokizono, H. Okamoto, Y. Yuri
    HU/AdSM, Higashi-Hiroshima
  • X.-P. Li
    Skyworks Solutions, Inc., Newbury Park. California
  • A. Sessler
    LBNL, Berkeley, California
  Funding: * Work performed under the auspices of the U.S. Department of Energy.

Previously it has been shown that the maintenance condition for a crystalline beam requires that there not be a resonance between the crystal phonon frequencies and the frequency associated with a beam moving through a lattice of N periods. This resonance can be avoided provided the phonon frequencies are all below half of the lattice frequency. Here we make a detailed study of the phonon modes of a crystalline beam. Analytic results obtained in a “smooth approximation” using the ground-state crystalline beam structure is compared with numerical evaluation employing Fourier transform of Molecular Dynamic (MD) modes. The MD also determines when a crystalline beam is stable. The maintenance condition, when combined with either the simple analytic theory or the numerical evaluation of phonon modes, is shown to be in excellent agreement with the MD calculations of crystal stability.

[1] X-P. Li, A. M. Sessler, J. Wei, EPAC (1994) p. 1379 - 1381. ‘Necessary Conditions for Attaining a Crystalline Beam''}[2] J. Wei, H. Okamoto, A.M. Sessler, Phys. Rev. Lett., Vol. 80, p. 2606-2609 (1998).

 
 
TPAT083 Computational Study of the Beam-Beam Effect in Tevatron Using the LIFETRAC Code luminosity, simulation, optics, antiproton 4117
 
  • A. Valishev, Y. Alexahin, V. Lebedev
    Fermilab, Batavia, Illinois
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk
  Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy.

Results of a comprehensive numerical study of the beam-beam effect in the Tevatron are presented including the dependence of the luminosity lifetime on the tunes, chromaticity and optics errors. These results help to understand the antiproton emittance blow-up routinely observed in the Tevatron after the beams are brought into collision. To predict a long term luminosity evolution, the diffusion rates are increased to represent long operation time (~day) by using a small number of simulated turns. To justify this approach, a special simulation study of interplay between nonlinear beam-beam resonances and diffusion has been conducted. A number of ways to mitigate the beam-beam effects are discussed, such as increasing bunch spacing, separation between the beams and beam-beam compensation with electron lenses.

 
 
TPAT089 Cooling Dynamics Studies and Scenarios for the RHIC Cooler electron, ion, luminosity, simulation 4236
 
  • A.V. Fedotov, I. Ben-Zvi, V. Litvinenko
    BNL, Upton, Long Island, New York
  • A.O. Sidorin, A.V. Smirnov, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-98CH10886

In this paper, we discuss various cooling dynamics studies for RHIC, such as an equilibrium process between intra-beam scattering within ion bunch and electron cooling, critical number of electrons needed, magnetized cooling logarithm and resulting requirements on parameters of electron beam, effects of solenoid errors, etc. We also present simulations of various possibilities of using electron cooling at RHIC, which includes cooling at the top energy, pre-cooling at low energy, aspects of transverse and longitudinal cooling and their impact on the luminosity. Electron cooling at various collision energies both for heavy ions and protons is also discussed.

 
 
TPAT090 Simulations of High-Energy Electron Cooling electron, ion, luminosity, simulation 4251
 
  • A.V. Fedotov, I. Ben-Zvi, Yu.I. Eidelman, V. Litvinenko, N. Malitsky
    BNL, Upton, Long Island, New York
  • D.L. Bruhwiler
    Tech-X, Boulder, Colorado
  • I.N. Meshkov, A.O. Sidorin, A.V. Smirnov, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-98CH10886.

High-energy electron cooling of RHIC presents many unique features and challenges. An accurate estimate of the cooling times requires a detailed calculation of the cooling process, which takes place simultaneously with various diffusive mechanisms in RHIC. In addition, many unexplored effects of high-energy cooling in a collider complicate the task of getting very accurate estimates of cooling times. To address these high-energy cooling issues, a detailed study of cooling dynamics based on computer codes is underway at Brookhaven National Laboratory. In this paper, we present an update on code development and its application to the high-energy cooling dynamics studies for RHIC.

 
 
TPAT091 IBS for Ion Distribution Under Electron Cooling lattice, ion, luminosity, simulation 4263
 
  • A.V. Fedotov, I. Ben-Zvi, Yu.I. Eidelman, V. Litvinenko, G. Parzen
    BNL, Upton, Long Island, New York
  • A.O. Sidorin, A.V. Smirnov, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-98CH10886.

Standard models of the intra-beam scattering (IBS) are based on the growth of the rms beam parameters for a Gaussian beam distribution. As a result of electron cooling, the core of beam distribution is cooled much faster than the tails, producing a denser core. Formation of such a core is an important feature since it plays dominant role in the luminosity increase. A simple use of standard rms-based IBS approach may significantly underestimate IBS for the beam core. A detailed treatment of IBS, which depends on individual particle amplitudes, was recently proposed by Burov,* with an analytic formulation done for a Gaussian distribution. However, during the cooling process the beam distribution quickly deviates from a Gaussian profile. To understand the extent of the dense core formation in the ion distribution, the "core-tail" model for IBS, based on the diffusion coefficients for bi-Gaussian distributions, was employed in cooling studies for RHIC. In addition, the standard IBS theory was recently reformulated for rms parameters growth of a bi-Gaussian distribution by Parzen.** In this paper, we compare various approaches to IBS treatment for such distribution. Its impact on the luminosity is also discussed.

*A. Burov, FERMILAB-TM-2213 (2003). **G. Parzen, Tech Note C-AD/AP/150 (2004).

 
 
TPAT093 Operations and Performance of RHIC as a Cu-Cu Collider luminosity, collider, ion, 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.

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

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

 
 
TOAB002 First Results from the VUV FEL at DESY electron, radiation, photon, undulator 127
 
  • B. Faatz
    DESY, Hamburg
  The VUV-FEL is an upgrade of the TTF1-FEL, which was taken in operation until end 2002. During this phase of the project it showed lasing in the wavelength range from 80-120 nm and it successfully provided beam for two pilot experiments. For over one year, the machine has been redesigned and upgraded, based on the experience gained during the first phase, to a user facility extending the wavelength range. Commissioning started in february 2004. In this contribution, the characterization of the VUV-FEL will be discussed, its electron beam parameters, photon beam properties and the status of the coming user experiments.  
 
TOAB004 An Optimized Low-Charge Configuration of the Linac Coherent Light Source linac, undulator, gun, radiation 344
 
  • P. Emma, Z. Huang, C. Limborg-Deprey, J. Wu
    SLAC, Menlo Park, California
  • W.M. Fawley, M.S. Zolotorev
    LBNL, Berkeley, California
  • S. Reiche
    UCLA, Los Angeles, California
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. The nominal parameter set is founded on a 1-nC bunch charge and normalized emittance of about 1 micron. The most challenging issues, such as emittance generation, wakefields, and coherent synchrotron radiation (CSR), are associated with the high bunch charge. In the LCLS in particular, with its strong linac wakefields, the bunch compression process produces sharp temporal horns at the head and tail of the bunch with degraded local emittance, effectively wasting much of the charge. The sharp horns intensify CSR in the bends and further drive a strong resistive-wall wakefield in the long FEL undulator. Although these issues are not insurmountable, they suggest a lower bunch charge may be more suitable. This study uses a 0.2-nC bunch charge and 0.85-micron emittance with only 30 A of peak current in the injector, producing the same FEL saturation length. The resulting performance is more stable, has negligible resistive-wall wakefield, greatly reduced CSR effects, and no transverse wakefield emittance dilution in the linac, with no change to the baseline engineering design.

 
 
TOAB009 Generation of Short X-Ray Pulses Using Crab Cavities at the Advanced Photon Source optics, radiation, sextupole, simulation 668
 
  • K.C. Harkay, M. Borland, Y.-C. Chae, G. Decker, R.J. Dejus, L. Emery, W. Guo, D. Horan, K.-J. Kim, R. Kustom, D.M. Mills, S.V. Milton, G. Pile, V. Sajaev, S.D. Shastri, G.J. Waldschmidt, M. White, B.X. Yang
    ANL, Argonne, Illinois
  • A. Zholents
    LBNL, Berkeley, California
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

There is growing interest within the user community to utilize the pulsed nature of synchrotron radiation from storage ring sources. Conventional third-generation light sources can provide pulses on the order of 100 ps but typically cannot provide pulses of about 1 ps that some users now require to advance their research programs. However, it was recently proposed by A. Zholents et al. to use rf orbit deflection to generate subpicosecond X-ray pulses.* In this scheme, two crab cavities are used to deliver a longitudinally dependent vertical kick to the beam, thus exciting longitudinally correlated vertical motion of the electrons. This makes it possible to spatially separate the radiation coming from different longitudinal parts of the beam. An optical slit can then be used to slice out a short part of the radiation pulse, or an asymetrically cut crystal can be used to compress the radiation in time. In this paper, we present a feasibility study of this method applied to the Advanced Photon Source. We find that the pulse length can be decreased down to a few-picosecond range using superconducting crab cavities.

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

 
 
TOAD004 The Possibility of Noninvasive Micron High Energy Electron Beam Size Measurement Using Diffraction Radiation target, radiation, electron, background 404
 
  • G.A. Naumenko, A. Potylitsyn
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
  • S. Araki, A. Aryshev, H. Hayano, V. Karataev, T. Muto, J.U. Urakawa
    KEK, Ibaraki
  • D. Cline, Y. Fukui
    UCLA, Los Angeles, California
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • M.C. Ross
    SLAC, Menlo Park, California
  During the last years a noninvasive method for beam size measurement based on the optical diffraction radiation (ODR) has been in progress (P. Karataev, et al., Physical Review Letters 93, 244802 (2004). However this technique encounters with hard sensitivity limitation for electron energies larger than several GeV. For example, for SLAC conditions the sensitivity of this method is 4 orders smaller than an appropriate one. We suggest to use a "dis-phased" slit target, where two semi-planes are turned with respect to each other at a small "dis-phased" angle. In order to ensure the interference between the diverged radiation beams we use a cylindrical lens. This method has much better sensitivity and resolution. A "dis-phased" angle 10 milliradians gives the optimal sensitivity to 5 microns transversal beam size. The theoretical model for calculating the ODR radiation from such targets (including focusing by cylindrical lens) is presented. It is shown that the sensitivity of this method does not depend on the Lorenz-factor directly. The target with the "dis-phased" angle 6.2 milliradians and the slit width 425 microns was manufactured for experimental test. Some preliminary experimental results are presented.  
 
TOPC002 Residual-Gas-Ionization Beam Profile Monitors in RHIC electron, coupling, background, heavy-ion 230
 
  • R. Connolly, R.J. Michnoff, S. Tepikian
    BNL, Upton, Long Island, New York
  Funding: Work performed under Contract #DE-AC02-98CH10886 under the auspices of the U.S. Department of Energy.

Four ionization profile monitors (IPMs) are in RHIC to measure vertical and horizontal beam profiles in the two rings. These work by measuring the distribution of electrons produced by beam ionization of residual gas. During the last two years both the collection accuracy and signal/noise ratio have been improved. An electron source is mounted across the beam pipe from the collector to monitor microchannel plate (MCP) aging and the signal electrons are gated to reduce MCP aging and to allow charge replenishment between single-turn measurements. Software changes permit simultaneous measurements of any number of individual bunches in the ring. This has been used to measure emittance growth rates on six bunches of varying intensities in a single store. Also the software supports FFT analysis of turn-by-turn profiles of a single bunch at injection to detect dipole and quadrupole oscillations.

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

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

 
 
TOPC005 Transverse Emittance Blow-Up Due to the Operation of Wire Scanners, Analytical Predictions and Measurements scattering, simulation, proton, betatron 437
 
  • F. Roncarolo, B. Dehning
    CERN, Geneva
  Wire Scanner monitors are used in the CERN accelerators to measure the transverse beam size. In the SPS and the LHC they will serve as calibration devices for other emittance monitors. The PSB, PS and SPS are equipped with scanners which move through the beam a 30 um wire, with a speed that can vary between 0.4 to 20 m/s. During each scan, the beam suffers an emittance blow up, due to multiple Coulomb scattering of the beam protons on the lattice nuclei of the wire material. The effect depends on the particles' energy, the betatron function at the monitor location and on the wire characteristics (material, diameter and speed). In this paper we will present a comparison of the analytically predicted emittance increase caused by the instruments and a number of experimental measurements. For the small LHC beams the relative emittance blow-up can exceed a few 10e-2.  
 
TOPB004 Overview of Energy Recovery Linacs electron, linac, gun, radiation 382
 
  • I.V. Bazarov
    Cornell University, Department of Physics, Ithaca, New York
  Funding: Supported by the NSF.

Existing Energy Recovery Linacs (ERLs) are successfully operated as kW-class average power infrared Free Electron Lasers (FELs). Various groups worldwide actively pursue ERLs as a technology of choice for a number of new applications. These include high brilliance light sources in a wide range of photon energies utilizing both spontaneous and FEL radiation production techniques, electron cooling of ion beams, and ERL-based electron-ion collider. All of these projects seek in various ways to extend performance parameters possible in ERLs beyond what has been achieved in existing relatively small scale demonstration facilities. The demand is for much higher average currents, significantly larger recirculated beam energies and powers and substantially improved electron sources. An overview of the ongoing ERL projects will be presented along with the summary of the progress that is being made in addressing the outstanding issues in this type of accelerators.

 
 
TPPE001 The HERA Volume H- Source electron, plasma, extraction, vacuum 788
 
  • J. Peters
    DESY, Hamburg
  Funding: The support of EEC (Contract HPRI-CT-2001-50021) is gratefully acknowledged.

The HERA RF-Volume Source is the only source that delivers routinely a H – current of 40 mA without Cs. It has been running for years without interruption for maintenance. The production mechanism for H – ions in this type of source is still under discussion. Laser photodetachment measurements have been done at DESY in order to measure the H – distribution in the source. The measurements were done also under extraction conditions at high voltage. The dependency of the quality of the Hminus beam on the frequency was investigated. A frequency range of 1.65 – 9 Mhz was scanned and the emittance was measured for several Hminus currents up to 40 mA. The results of our investigations make further source improvements possible. Recently currents of 60 mA were reached.

 
 
TPPE011 A Compact High-Brightness Heavy-Ion Injector ion, plasma, heavy-ion, extraction 1263
 
  • G.A. Westenskow, D.P. Grote, E. F. Halaxa
    LLNL, Livermore, California
  • F.M. Bieniosek, J.W. Kwan
    LBNL, Berkeley, California
  Funding: This work has been performed under the auspices of the U.S. DOE by UC-LBNL under contract DE-AC03-76SF00098 and by UC-LLNL under contract W-7405-ENG-48, for the Heavy Ion Fusion Virtual National Laboratory.

To provide compact high-brightness heavy-ion beams for Heavy Ion Fusion (HIF) accelerators, we have been experimenting with merging multi-beamlets in an injector which uses an RF plasma source. In an 80-kV 20-microsecond experiment, the RF plasma source has produced up to 5 mA of Ar+ in a single beamlet. An extraction current density of 100 mA/cm2 was achieved, and the thermal temperature of the ions was below 1 eV. More than 90% of the ions were in the Ar+ state, and the energy spread from charge exchange was found to be small. We have tested at full voltage gradient the first 4 gaps of a 61-beamlet injector design. Einzel lens were used to focus the beamlets while reducing the beamlet to beamlet space charge interaction. We will report on a converging 119 multi-beamlet source. Although the source has the same optics as a full 1.6 MV injector system, the test will be carried out at 400 kV due to the test stand HV limit. We will measure the beam’s emittance after the beamlets are merged and have been transported through an electrostatic quadrupole. Our goal is to confirm the emittance growth and to demonstrate the technical feasibility of building a driver-scale HIF injector.

 
 
TPPE012 Using the Orbit Tracking Code Z3CYCLONE to Predict the Beam Produced by a Cold Cathode PIG Ion Source for Cyclotrons under DC Extraction plasma, ion, ion-source, cyclotron 1297
 
  • E.R. Forringer, H.G. Blosser
    NSCL, East Lansing, Michigan
  Experimental measurements of the emittance and luminosity of beams produced by a cold-cathode Phillips Ionization Guage (PIG) ion source for cyclotrons under dc extraction are reviewed. (The source being studied is of the same style as ones that will be used in a series of 250 MeV proton cyclotrons being constructed for cancer therapy by ACCEL Inst, Gmbh, of Bergisch Gladbach, Germany.) The concepts of 'plasma boundary' and 'plasma temperature' are presented as a useful set of parameters for describing the initial conditions used in computational orbit tracking. Experimental results for r-pr and z-pz emittance are compared to predictions from the MSU orbit tracking code Z3CYCLONE with results indicating that the code is able to predict the beam produced by these ion sources with adequate accuracy such that construction of actual cyclotrons can proceed with reasonably prudent confidence that the cyclotron will perform as predicted.  
 
TPPE013 Simulations of Solenoid and Electrostatic Quadrupole Focusing of High Intensity Beams from ECR Ion Source at NSCL focusing, quadrupole, space-charge, simulation 1336
 
  • Q. Zhao, A.I. Balabin, M. Doleans, F. Marti, J.W. Stetson, X. Wu
    NSCL, East Lansing, Michigan
  Solenoidal focusing has been widely used to focus beams at various injectors for its axisymmetric focusing with reasonable effectiveness. Experiments and simulations have shown that space charge effects can significantly deteriorate the beam quality when solenoidal focusing is used in a multi-component beam. This is due to the magnetic focusing strength dependence on the beam charge-to-mass ratio. Electrostatic quadrupole focusing has been explored as an alternate option at NSCL for the injection line of the superconducting cyclotron. We present in this paper the results of simulations for both systems. The electrostatic quadrupoles have been optimized to reduce the radial dependent aberrations and to increase the transmission efficiency.  
 
TPPE018 Characterization of a Tubular Hot-Cavity Surface Ionization Source ion, target, ion-source, plasma 1581
 
  • Y. Liu, H. Z. Bilheux, Y. Kawai
    ORNL, Oak Ridge, Tennessee
  Funding: Managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC05-00OR22725.

Elements with low ionization potentials can be efficiently ionized by positive surface ionization. It has been experimentally observed and theoretically shown that the ionization efficiency in a hot-cavity can be significantly higher than expected for the surface ionization mechanism. This is explained by the existence of a thermal plasma inside the cavity consisting of surface ionized ions and thermionic electrons. We have investigated the suggested ioniation mechanisms in a tubular hot-cavity surface ionization source where the area of the exit aperture is small compared with the tube inner surface. Thermal analyses of the tubular cavity and calculated mean number of wall collisions of a neutral particle in the cavity before escaping through the exit aperture are presented. Measured emittance and ionization efficiencies of various elements as a function of the cavity temperature for different cavity materials are discussed.

 
 
TPPE023 Development and Performance of a Proton and Deuteron ECR Ion Source proton, ion-source, ion, simulation
 
  • K. Dunkel, F. Kremer, C. Piel, J. Plitzko
    ACCEL, Bergisch Gladbach
  A 5mA proton and deuteron rf source is under development at ACCEL. This source will provide the front end of our superconducting proton/deuteron linear accelerator. The design of the source is based on the proven AECL design of a 100 mA proton source. The paper will describe the design of the source and the layout of the test bench currently set up at ACCEL to characterize the source. Results of the beam dynamic simulations performed to optimize the source geometry based on KOBRA 3D will be presented and compared with first measurement results.  
 
TPPE025 Separating the Penning and Analysing Fields in the ISIS H- Ion Source ion, ion-source, vacuum, extraction 1910
 
  • D.C. Faircloth, R. Sidlow, M. Whitehead, T.W. Wood
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  Funding: This work was supported by the European Union High Performance Negative Ion Source (HP-NIS) network, contract number HPRI-CT-2001-50021.

The development of H- ion sources with performances exceeding those achieved today is a key requirement for the next generation of high power proton accelerators. The Penning surface plasma source development program at ISIS is now well established. To allow different ion source designs to be fully tested, the ability to vary the Penning field is required. Until now the Penning field has been generated by the same magnetic circuit that creates the analyzing field, giving no practical way of altering the Penning field alone. This paper describes the infrastructure changes required to allow the Penning field to be independently varied. The effect the Penning field has on beam current, emittance and discharge stability are discussed.

 
 
TPPE034 Possible Scheme of the Analyzing Part of a Cyclotron Injection Beamline with Higher Energy ion, focusing, injection, vacuum 2345
 
  • Yu. Kazarinov
    JINR, Dubna, Moscow Region
  • J.W. Stetson, P.A. Zavodszky
    NSCL, East Lansing, Michigan
  Funding: This work was supported in part by the National Science Foundation under grant PHY-0110253.

The ion beam produced with an ECR ion source (ECRIS) with an extraction voltage of 30 kV may be additionally accelerated using a negative voltage of -30 kV applied to the last electrode of the extraction system, connected to the beamline biased to the same -30 kV potential. In this way the kinetic energy of the beam is increased to 60 keV/q, decreasing to half the space charge effect on the beam emittance. Using a large gap analyzing magnet placed right after the ECRIS and no focusing element, the transmission is still close to 100%. The voltage on the beamline must be kept constant from the ECRIS till the image focal plane of the analyzing magnet where the full separation of the beam charge states is achieved. An insulator break separates the biased beamline from the downstream section, which is at zero potential. Passing through this section of the beamline, the ion beam is decelerated to 30 keV/q, the energy necessary for the injection in the cyclotron. In order to prevent the increase of the beam divergence, a focusing solenoid is installed behind the break point. This work will present the results of a simulation of the transport of an argon beam in the proposed beamline.

 
 
TPPE040 RF and Magnetic Measurements on the SPARC Photoinjector and Solenoid at UCLA gun, cathode, coupling, linac 2624
 
  • J.B. Rosenzweig, A.M. Cook, M.P. Dunning, P. Frigola, G. Travish
    UCLA, Los Angeles, California
  • D.T. Palmer
    SLAC, Menlo Park, California
  • C. Sanelli, F. Tazzioli
    INFN/LNF, Frascati (Roma)
  Funding: This work is supported by U.S. Dept. of Energy grant DE-FG03-92ER40693.

The rf photocathode gun and the solenoid for the SPARC project at INFN-LNF (Frascati) have been fabricated and undergone initial testing at UCLA. The advanced aspects of the design of these devices are detailed. Final diagnosis of the tuning of the RF gun performance, including operating mode frequency and field balance, is described. The emittance compensating solenoid magnet, which is designed to be tuned in longitudinal position by differential excitation of the coils, has been measured using Hall probe scans for field profiling, and pulsed wire methods to determine the field center.

 
 
TPPE043 Electron Beam Generation and Transport for the RHIC Electron Cooler electron, space-charge, linac, cathode 2774
 
  • J. Kewisch, I. Ben-Zvi, X.Y. Chang
    BNL, Upton, Long Island, New York
  Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the U.S. Department of Energy.

An electron cooler, based on an Energy Recovery Linac (ERL) is under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. This will be the first electron cooler operating at high energy with bunched beams. A better understanding of the cooling process and more accurate measurements of Intra Beam Scattering in RHIC have imposed increased requirements on the electron accelerator: Besides a doubling of the bunch charge to 20 nC, the strength of the cooling solenoid was increased five-fold to 5 Tesla. The magnetic field on the cathode should be increased to 500 Gauss to match the magnetization required in the cooling solenoid. This paper reports the measures taken to minimize the electron beam emittance in the cooling section. The front-to-end simulation using different tracking codes is presented.

 
 
TPPE044 Upgrade of the Fermilab/NICADD Photoinjector Laboratory laser, quadrupole, linac, electron 2848
 
  • P. Piot, H. Edwards
    Fermilab, Batavia, Illinois
  • M. Huening
    DESY, Hamburg
  • T. W. Koeth
    Rutgers University, The State University of New Jersey, Piscataway, New Jersey
  • J.L. Li, R. Tikhoplav
    Rochester University, Rochester, New York
  Funding: This work was supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U.S. DOE, and by NICADD.

The Femilab/NICADD photoinjector laboratory (FNPL) is a 16 MeV electron accelerator dedicated to beam dynamics and advanced accelerator studies. FNPL will soon be capable of operating at 50 MeV, after the installation of a high gradient TESLA cavity. In this paper we present the foreseen design for the upgraded facility along with its performance. We discuss the possible application of 50 MeV beam including the possible use of FNPL as an injector for the superconducting module and test facility (SM&TF).

 
 
TPPE045 Normal-Conducting High Current RF Photoinjector for High Power CW FEL vacuum, coupling, rfq, simulation 2866
 
  • S.S. Kurennoy, D.C. Nguyen, D.L. Schrage, R.L. Wood
    LANL, Los Alamos, New Mexico
  • V. Christina, J. Rathke, T. Schultheiss
    AES, Medford, NY
  • L.M. Young
    TechSource, Santa Fe, New Mexico
  An RF photoinjector capable of producing high average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell, pi-mode, 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With average gradients of 7, 7, and 5 MV/m in its three accelerating cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and transverse rms emittance below 7 mm-mrad. Electromagnetic modeling has been used extensively to optimize ridge-loaded tapered waveguides and RF couplers, and led to a new, improved coupler iris design. The results, combined with a thermal and stress analysis, show that the challenging problem of cavity cooling can be successfully solved. Fabrication of a demo 100-mA (at 35 MHz bunch repetition rate) photoinjector is underway. The design is scalable to higher average currents by increasing the electron bunch repetition rate, and provides a path to a MW-class FEL. This paper presents the cavity design and details of RF coupler modeling.  
 
TPPE051 The Optimization of the Electron Injector Resonance System Based on the Evanescent Oscillations electron, bunching, simulation, space-charge 3170
 
  • S.A. Perezhogin, M.I. Ayzatskiy, K. Kramarenko, V.A. Kushnir, V.V. Mytrochenko, Z.V. Zhiglo
    NSC/KIPT, Kharkov
  The report presents the results of the bunching system optimization and electrons motion simulation in the compact S – band injector. The injector consists of the low-voltage diode electron gun and optimized bunching system based on the resonant system with the evanescent oscillations. The amplitude of RF electrical field is increased along the axis of the bunching system. The resonance system optimization allows to obtain electron bunches with the phase length less than 10° (for 70 % particles) at the injector exit.  
 
TPPE055 DC-SC Photoinjector with Low Emittance at Peking University gun, electron, cathode, laser 3325
 
  • R. Xiang, Y.T. Ding, J. Hao, S.L. Huang, X.Y. Lu, S.W. Quan, B.C. Zhang, K. Zhao
    PKU/IHIP, Beijing
  High average power Free Electron Lasers require the high quality electron beams with the low emittance and the sub-picosecond bunches. The design of DC-SC photoinjector, directly combining a DC photoinjector with an SRF cavity, can produce high average current beam with moderate bunch charge and high duty factor. Because of the DC gun, the emittance increases quickly at the beginning, so a carefully design is needed to control that. In this paper, the simulation of an upgraded design has been done to lower the normalized emittance below 1.5mm·mrad. The photoinjector consists of a DC gap and a 2+1/2-cell SRF cavity, and it is designed to produce 4.2 MeV electron beams at 100pC bunch charge and 81.25MHz repetition rate (8 mA average current).  
 
TPPE056 Emittance Measurement with Upgraded RF Gun System at SPring-8 quadrupole, laser, gun, simulation 3348
 
  • A. Mizuno, H. Dewa, H. Hanaki, T. Taniuchi, H. Tomizawa
    JASRI/SPring-8, Hyogo
  • M. Uesaka
    UTNL, Ibaraki
  A single cell S-band RFgun has been developed at the SPring-8 since 1996. The minimum normalized beam emittance, measured with double slits' scanning method in 2002, was 2.3 pi mm mrad at the exit of the gun cavity with charge of 0.1 nC/bunch. In 2004, we installed a following accelerator structure to investigate beam behavior of the whole injector system. In this paper, we report emittance measurement results of upgraded system, using variable quadrupole magnet method. The minimum emittance of 2.0 pi mm mrad with a net charge of 0.14 nC/bunch were able to be measured.  
 
TPPE059 New Electron Gun System for BEPCII gun, electron, simulation, linac
 
  • B. Liu, Y.L. Chi, M. Gu, C. Zhang
    IHEP Beijing, Beijing
  The new electron gun system for BEPCII has been put into operation since Nov. 2004. The article describes the design, experiment and operation of this new system. The design current of the gun is 10 A for the pulse lengths of 1 ns, 2.5 ns and 1 μs with repetition rate of 50 Hz. The gun is operated with a pulsed high voltage power supply which can provide up to 200 kV high voltage. Computer simulations have been carried out in the design stage, including simulation of the gun geometry and beam transportation. Some important relation curves are obtained during the experiment. Two-bunch operation is available and some elementary tests have been performed. New scheme of the gun control system based on EPICS is also presented. The real operation shows that the design and manufacturing is basically successful.  
 
TPPE066 Geometry Optimization of DC/RF Photoelectron Gun gun, cathode, electron, simulation 3679
 
  • P. Chen, R. Yi, D. Yu
    DULY Research Inc., Rancho Palos Verdes, California
  Funding: *Work supported by DOE SBIR Grant No. DE-FG02-03ER83878.

Pre-acceleration of photoelectrons in a pulsed, high voltage, short, dc gap and its subsequent injection into an rf gun is a promising method to improve electron beam emittance in rf accelerators. Simulation work has been performed in order to optimize the geometric shapes of a dc/rf gun and improve electron beam properties. Variations were made on cathode and anode shapes, dc gap distance, and inlet shape of the rf cavity. Simulations showed that significant improvement on the normalized emittance (< 1 mm-mrad), compared to a dc gun with flat cathode, could be obtained after the geometric shapes of the gun were optimized.

 
 
TPPP001 Design of Damping Ring for SuperKEKB dynamic-aperture, damping, linac, positron 773
 
  • M. Kikuchi
    KEK, Ibaraki
  In the SuperKEKB, a plan upgrading the KEKB to higher luminosity of (2.5-5) x1035 cm2/sec, the beam currents are 9.4 A for the LER (3.5 GeV-electrons) and 4.1 A for the HER (8 GeV-positrons). In order to supply the HER with the positron beam, which is currently injected to the LER, the field gradient of the injector linac has to be increased. To meet this requirement, the S-band accelerating structures placed at the beam energy greater than 1 GeV, after the positron target, are replaced with C-band structures. A damping ring (DR) is indispensable since the aperture of the C-band structure is much smaller than the beam emittance. In this paper, we describe on the design of DR. We adopt a new cell structure for DR; FODO cell with alternating bends, where one of two bends in a cell is reversed. One of advantages of the proposed ring is that very small, even negative, momentum compaction factor is easily achieved by properly choosing the bend-angle ratio of the reverse bend to the main bend. Tracking simulation for the proposed DR has shown that it has very large dynamic aperture in both transverse and longitudinal phase space, for very wide tune space.  
 
TPPP014 Ionization Cooling Using a Parametric Resonance resonance, focusing, betatron, luminosity 1374
 
  • Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • R.P. Johnson
    Muons, Inc, Batavia
  Funding: This work was supported in part by DOE SBIR grant DE-FG02-04ER84016.

Muon collider luminosity depends on the number of muons in the storage ring and on the transverse size of the beams in collision. Ionization cooling as it is presently envisioned will not cool the beam sizes sufficiently well to provide adequate luminosity without large muon intensities. A new idea to combine ionization cooling with parametric resonances has been developed that will lead to beams with much smaller sizes so that high luminosity in a muon collider can be achieved with fewer muons. In the linear channel described here, a half integer resonance is induced such that the normal elliptical motion of particles in x-x' phase space becomes hyperbolic, with particles moving to smaller x and larger x' as they pass down the channel. Thin absorbers placed at the focal points of the channel then cool the angular divergence of the beam by the usual ionization cooling mechanism where each absorber is followed by RF cavities. We discuss the theory of Parametric-resonance Ionization Cooling, including the sensitivity to aberrations and the need to start with a beam that has already been cooled adequately.

 
 
TPPP015 ELIC at CEBAF electron, ion, collider, luminosity 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.

 
 
TPPP017 Beam-Beam Effects in the Ring-Ring Version of eRHIC resonance, beam-beam-effects, luminosity, simulation 1520
 
  • J. Shi, L. Jin
    KU, Lawrence, Kansas
  • D. Wang, F. Wang
    MIT, Middleton, Massachusetts
  Funding: The U.S. Department of Energy under Grant No. DE-FG02-04ER41288.

The eRHIC is a proposed electron ring at the RHIC that will provide collisions between a polarized 5-10 GeV electron beam and an ion beam from one of the RHIC rings. In order to achieve proposed high luminosity, large bunch current and small beta-functions at the IP has to be employed. Such measures result in large beam-beam parameters, 0.029 and 0.08 for the electron beam and 0.0065 and 0.0033 for the proton beam in the horizontal and vertical plane, respectively, in the current ZDR design. The beam-beam effect especially the coherent beam-beam effect is therefore one of important issues to the eRHIC. Moreover, the proposed configuration of unequal circumferences of the electron and proton rings could further enhance the coherent beam-beam effect. The beam-beam effect of eRHIC has therefore been studied with a self-consistent beam-beam simulation by using the particle-in-cell method. Beam-beam limits of the electron and proton beam were examined as thresholds of the onset of coherent beam-beam instability. For the proposed luminosity, the electron and proton bunch currents optimized with the consideration of the beam-beam effect will be discussed.

 
 
TPPP018 Progress on the MICE Liquid Absorber Cooling and Cryogenic Distribution System vacuum, factory, focusing, scattering 1601
 
  • M.A. Green
    LBNL, Berkeley, California
  • E. Baynham, T.W. Bradshaw, P. Drumm, Y. Ivanyushenkov
    CCLRC/RAL, Chilton, Didcot, Oxon
  • M.A.C. Cummings
    Northern Illinois University, DeKalb, Illinois
  • S. Ishimoto
    KEK, Ibaraki
  • W. Lau, S.Q. Yang
    OXFORDphysics, Oxford, Oxon
  Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC03-76SF00098.

This report describes the progress made on the design of the liquid hydrogen absorber for the international Muon Ionization Cooling Experiment (MICE). The absorber consists of a 21-liter vessel that contains liquid hydrogen (1.5 kg) or liquid helium (2.63 kg). The cryogen vessel is within the warm bore of the superconducting focusing magnet for the MICE. The purpose of the magnet is to provide a low beam beta region within the absorber. For safety reasons, the vacuum vessel for the hydrogen absorber is separated from the vacuum vessel for the superconducting magnet and the vacuum that surrounds the RF cavities or the detector. The absorber has two 300 mm-diameter thin aluminum windows. The vacuum vessel around the absorber has a pair of thin aluminum windows that separate the absorber vacuum space from adjacent vacuum spaces. Because the muon beam in MICE is of low intensity, there is no beam heating in the absorber. As a result, the absorber can be cooled using a single 4 K cooler. This report describes progress on the MICE liquid absorber and its cryogenic cooling system.

 
 
TPPP032 Proposal for a Multi-Use Test Beam Area in the SLAC B-Line linac, optics, quadrupole, target 2221
 
  • P. Emma, L.D. Bentson, R.A. Erickson, H. Fieguth, J. Seeman, A. Seryi
    SLAC, Menlo Park, California
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

With the impending construction of the Linac Coherent Light Source (LCLS) at SLAC, displacing the well-used Final Focus Test Beam (FFTB) area, there is growing interest in developing a new test beam facility, available during LCLS operations and located in the old B-Line tunnel at the end of the linac. The success of the Sub-Picosecond Pulse Source (SPPS) and the desire to preserve this capacity suggests a new beamline with similar or improved electron beam quality, including bunch length compression to 10 microns. Beam availability during LCLS operations requires a new 1.2-km bypass line connecting the 2/3-point of the linac with the B-Line. A second operating mode, with LCLS not in use, involves a trajectory directly from the end of the linac to the B-line. This feature provides the highest beam quality at 30 GeV, and also allows a possible third operational mode by deflecting a few of the very high-brightness 120-Hz, 14-GeV LCLS bunches at low rate (1-10 Hz) into the B-line. Finally, linear collider research can be carried out in a short final focus system at the end of the B-Line, capable of producing a 70-nm rms beam size. We describe a possible design for these systems.

 
 
TPPP039 Geant Simulation of Six-Dimensional Cooling of a Muon Beams in a Ring Coolers simulation, dipole, focusing, beam-losses 2580
 
  • A. Klier, G.G. Hanson
    UCR, Riverside, California
  The reduction of the phase-space volume of the beam (cooling) is essential for both muon colliders and neutrino factories. In a muon collider, in particular, the six-dimensional (6D) emittance must be reduced by six orders of magnitude. Cooling the beam in all phase space dimensions can be done through emittance exchange, where the beam loses energy passing through wedge-shaped absorbers in a dispersive magnetic field, designed in a way that fast muons go through more absorber material than slow ones and lose more energy. The longitudinal momentum is then regained using RF cavities. We simulate ring coolers, in which the beam undergoes 6-dimensional cooling through emittance exchange while rotating several times in the ring. The simulation software is a Geant3-based package, specially designed this purpose, with changing electric fields in RF cavities treated correctly. Magnetic fields are read from external maps. Some ring cooler designs and cooling simulation results are presented.  
 
TPPP041 Recent Developments on the Muon-Facility Design Code ICOOL simulation, multipole, focusing, factory 2651
 
  • R.C. Fernow
    BNL, Upton, Long Island, New York
  Funding: Work supported by U.S. Department of Energy.

Current ideas for designing neutrino factories and muon colliders require unique configurations of fields and materials to prepare the muon beam for acceleration. We have continued the development of the 3D tracking code ICOOL for examining possible system configurations. Development of the ICOOL code began in 1996 in order to simulate the process of ionization cooling. This required tracking in magnetic focusing lattices, together with interactions in shaped materials that must be placed in the beam path.* The most important particle interactions that had to be simulated were energy loss and straggling. Since the optimum way of designing a cooling channel was not known, the code had to have a flexible procedure for specifying field and material geometries. Eventually the early linear cooling channels evolved into cooling rings. In addition the designs require many other novel beam manipulations besides ionization cooling, such as pion collection in a high field solenoid, rf phase rotation, and acceleration in FFAG rings. We describe new features that have been incorporated in ICOOL for handling these new requirements. A suite of auxilliary codes have also been developed for pre-processing, post-processing, and optimization.

*R.C. Fernow, ICOOL: a simulation code for ionization cooling of muon beams, Proc. 1999 Part. Accel. Conf., New York, p. 3020.

 
 
TPPP048 A Compact 6D Muon Cooling Ring closed-orbit, dipole, simulation, lattice 3025
 
  • H.G. Kirk, S.A. Kahn
    BNL, Upton, Long Island, New York
  • D. Cline, A.A. Garren
    UCLA, Los Angeles, California
  • F.E. Mills
    Fermilab, Batavia, Illinois
  Funding: U.S. Department of Energy.

We discuss a conceptual design for a compact muon cooling system based on a weak-focusing ring loaded with high-pressure Hydrogen gas. We demonstrate that such a ring will be capable of cooling a circulating muon beam in each of the three spatial dimensions so that 6d cooling of the muon beam phase space is achieved.

 
 
TPPP051 A Muon Cooling Ring with Curved Lithium Lenses simulation, scattering, factory, collider 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.  
 
TPPP052 Simulations of a Gas-Filled Helical Muon Beam Cooling Channel simulation, quadrupole, focusing, beam-cooling 3215
 
  • K. Yonehara, D.M. Kaplan
    Illinois Institute of Technology, Chicago, Illinois
  • K. Beard, S.A. Bogacz, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • R.P. Johnson, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
  Funding: This work was supported in part by DOE STTR/SBIR grants DE-FG02-02ER86145 and 03ER83722.

A helical cooling channel (HCC) has been proposed to quickly reduce the six-dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of a series of RF cavities filled with dense hydrogen gas that acts as the energy absorber for ionization cooling and suppresses RF breakdown in the cavities. Magnetic solenoidal, helical dipole, and helical quadrupole coils outside of the RF cavities provide the focusing and dispersion needed for the emittance exchange for the beam as it follows a helical equilibrium orbit down the HCC. In the work presented here, two Monte Carlo programs have been developed to simulate a HCC to compare with the analytic predictions and to begin the process of optimizing practical designs that could be built in the near future. We discuss the programs, the comparisons with the analytical theory, and the prospects for a HCC design with the capability to reduce the six-dimensional phase space emittance of a muon beam by a factor of over five orders of magnitude in a linear channel less than 100 meters long.

 
 
TPPP055 Simultaneous Bunching and Precooling Muon Beams with Gas-Filled RF Cavities target, simulation, factory, collider 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 quadrupole, dipole, collider, 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.

 
 
TPPT031 Coupler Design for the LCLS Injector S-Band Structures quadrupole, dipole, multipole, linac 2176
 
  • Z. Li, L.D. Bentson, J. Chan, D. Dowell, C. Limborg-Deprey, J.F. Schmerge, D.C. Schultz, L. Xiao
    SLAC, Menlo Park, California
  Funding: Work supported by the U.S. DOE Contract No. DE-AC03-76SF00515.

The LCLS injector is required to provide a 1-nC, 10-ps bunch with a normalized rms transverse projected emittance of less than 1.0-μm. The LCLS beam is generated and accelerated in a 1.6-cell S-band RF gun to 6-MeV followed by two SLAC 3-m S-band accelerator structures to further accelerate the beam to 135 MeV to move it out of the space-charge dominated regime. In the SLAC S-band structures, the RF power feed is through a single coupling-hole (single-feed coupler) which results in a field asymmetry. The time dependent multipole fields in the coupler induce a transverse kick along the bunch and cause the emittance to increase above the LCLS specification. To meet the stringent emittance requirements for the injector, the single-feed couplers will be replaced by a dual-feed racetrack design to minimize the multipole field effects. We will present detailed studies of the multipole fields in the S-band coupler and the improvements with the dual-feed racktrack design using the parallel finite element eigenmode solver Omega3P.

 
 
TPPT032 Modifications on RF Components in the LCLS Injector gun, quadrupole, cathode, linac 2233
 
  • C. Limborg-Deprey, D. Dowell, Z. Li, J.F. Schmerge, L. Xiao
    SLAC, Menlo Park, California
  Funding: This work was supported by U.S. Department of Energy, contract No. DE-AC03-76SF00515A06.

Design of the first generation LCLS injector has now been completed. Components are currently under fabrication and their installation is planned for 2006. We discuss the last modifications made on both the 1.6 cell S-Band RF gun and the SLAC S-Band accelerating structures to minimize the beam emittance. We present results from PARMELA computations which justify those modifications, in particular the suppression of the time dependent dipole and quadrupole kicks. Geometry changes to increase the mode separation between the 0 and PI modes are also presented. For the initial geometry with a mode separation of 3.5MHz, the emittance can increase if the appropriate injection time along the klystron pulse is not chosen. For a mode separation of 15MHz, this problem is minimized and the beam dynamics are improved leading to a substantial reduction of total projected emittance.

 
 
TPPT071 Preliminary Results on the Simultaneous Excitation of the TM010 and TE011 Modes in a Single Cell Niobium Cavity focusing, coupling, superconducting-RF, pick-up 3844
 
  • G. Ciovati, P. Kneisel
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by the U.S. DOE Contract No DE-AC05-84ER40150.

Simultaneous excitation of both TM010 and TE011 modes has been proposed recently for superconducting photoinjector applications to take advantage of the accelerating field of the TM mode, combined with the focusing magnetic field of the TE mode. Simultaneous excitation of both modes has been carried out on a CEBAF single cell cavity. The cavity has two beam pipe side-ports for each mode for input and pick-up couplers. Coupling to the TE011 mode is done by magnetic loop couplers while for the TM010 mode coaxial antennas are used. The TE011 mode has the property of having zero surface electric field, surface magnetic field orthogonal to the one in the TM010 mode and concentrated in the iris/wall regions of the cavity. The presence of both modes in the cavity at the same time can also be used to investigate the so-called high field Q-drop in the TM010 mode. This paper will present some preliminary result on the test of the single cell cavity at 2K.

 
 
TPPT090 Progress of 2-Cell Cavity Fabrication for Cornell ERL Injector vacuum, linac, coupling, superconductivity 4248
 
  • R.L. Geng, P. Barnes, M. Liepe, V. Medjidzade, H. Padamsee, A.K. Seaman, J. Sears, V.D. Shemelin, N. Sherwood
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Five 1300 MHz superconducting niobium cavities are to be used for the injector of Cornell ERL. The beam power requirement (100 kW each cavity) and the need to minimize emittance dilution due to the cavity structure have important impacts to the design and fabrication of these cavities. We plan to use Conflat stainless-steel flanges brazed to niobium tubes of niobium cavities. The first copper prototy cavity has been built and measured. Most parts for the first niobium cavity have been manufactured also. In this report, we will present the progress of the prototyping copper as well as niobium cavities.  
 
TPPT094 Design of the CW Cornell ERL Injector Cryomodule linac, higher-order-mode, damping, alignment 4290
 
  • M. Liepe, S.A. Belomestnykh, R.L. Geng, V. Medjidzade, H. Padamsee, V.D. Shemelin, V. Veshcherevich
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: This work is supported by Cornell University.

The Cornell ERL Prototype injector will accelerate bunches from an electron source to an energy of several MeV, while preserving the ultra-low emittance of the beam. The injector linac will be based on superconducting RF technology with five 2-cell RF cavities operated in cw mode. The beam tubes on one side of the cavities have been enlarged to propagate Higher-Order-Mode power from the cavities to broadband RF ring-absorbers located at 80 K between the cavities. The axial symmetry of these ferrite based absorbers, together with two symmetrically placed input couplers per cavity, avoids transverse on-axis fields, which would cause emittance growth. Each cavity is surrounded by a LHe vessel and equipped with a frequency tuner. The cryomodule provides the support and alignment for the cavity string, the LN cooling of the ferrite loads, and the 2K LHe cryogenic system for the high cw heat load of the cavities. In this paper we give an overview of the ERL injector cryomodule design.

 
 
TOPE003 Results from DR and Instrumentation Test Facilities damping, laser, coupling, quadrupole 305
 
  • J.U. Urakawa
    KEK, Ibaraki
  The KEK Accelerator Test Facility (ATF) is a 1.3GeV storage ring capable of producing ultra-low emittance electron beams and has a beam extraction line for ILC R&D. The ATF has proven to be an ideal place for researches with small, stable beams. 2x1010 single bunch and low current 20 bunch-train with 2.8nsec bunch spacing have been extracted to develop Nano-Cavity BPM’s, FONT, Nano Beam Orbit handling (FEATHER), Optical Diffraction Radiation (ODR) monitor, a precision multi-bunch laser-based beam profile monitor and polarized positron beam generation via backward-Compton scattering by the international collaboration. A set of three cavity BPM's is installed in the ATF extraction line on a set of extremely stiff supports. The KEK group installed another set of three BPM's, with their own support mechanism. The full set of 6 will prove extremely useful. In the DR (Damping Ring), we are researching the fast ion instability, micro-wave instability with four sets of damping wiggler and developing pulsed laser wire monitor, X-ray SR monitor, very fast kicker with about 1nsec rise/fall time to make ILC beam. I will report the recent results on above R&D’s.  
 
TOPE004 CLIC Progress Towards Multi-TeV Linear Colliders linac, luminosity, damping, collider 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.  
 
WOAA003 Progress and Plans for R&D and the Conceptual Design of the ILC Injector Systems positron, electron, damping, undulator 315
 
  • S. Guiducci
    INFN/LNF, Frascati (Roma)
  The International Linear Collider Injector is a complex of different subsystems that are strictly correlated: positron source, polarized electron source, damping rings, bunch compressor and spin rotator. The choice of parameters of each subsystem has a strong influence on the others. A description of the critical items requiring further R&D in order to finalize the choice of the parameters needed for the Conceptual Design is given. The status and plans of the R&D in progress on these items at a global level are reported.  
 
WPAE008 Redesign of a Low Energy Probe Head simulation, proton, injection, cyclotron 1105
 
  • Y.-N. Rao, G.H. Mackenzie, T.C. Ries
    TRIUMF, Vancouver
  The present situation of the low energy probe L·102 in TRIUMF cyctron is that the thickness of finger 5 is uniform in the radial direction and its weight which amounts to ~447 g is affecting its re-circulating ball mechanism and causing it to fall below the median plane over its range of movement (13.890 to 161.515 inch). We first made simulations to determine the optimum thickness of the probe head vs the radial length so as to reduce its weight. And then, we compared the simulation results with experimental measurements made. Finally, we calculated the temperature rise caused by the beam power dumped on the probe, and figured out the maximum beam current that can be dumped on the finger.  
 
WPAE014 Conceptual Design of a Longitudinal Halo Collimator for J-PARC Linac linac, collimation, simulation, optics 1413
 
  • M. Ikegami
    KEK, Ibaraki
  • T. Ohkawa
    JAERI, Ibaraki-ken
  In a high-intensity proton accelerator, avoidance of excess beam loss is essentially important to enable hands-on maintenance. To reduce the uncontrolled beam loss in the following ring, we plan to install a longitudinal halo collimator system in a beam transport line after the injector linac. The collimator system is supposed to have two main roles: One is the elimination of longitudinal tail or halo particles destined to be lost in the following ring, and the other is the removal of anomalous beams which can be resulted from, for example, RF discharge of an accelerating cavity. We plan to adopt a "periodic collimation scheme" in the collimator system taking advantage of the three-fold symmetry of the arc section. The momentum aperture of the collimator system is expected to be reduced by the factor of two adopting periodic collimation. In this paper, conceptual design of the collimator system is presented together with the results of particle simulations.  
 
WPAE029 Tevatron Beam-beam Compensation Project Progress electron, proton, antiproton, gun 2083
 
  • V.D. Shiltsev, R.J. Hively, V. Kamerdzhiev, A. Klebaner, G.F. Kuznetsov, A. Martinez, H. Pfeffer, G.W. Saewert, A. Semenov, D. Wolff, X. Zhang
    Fermilab, Batavia, Illinois
  • K. Bishofberger
    UCLA, Los Angeles, California
  • I. Bogdanov, E. Kashtanov, S. Kozub, V. Sytnik, L. Tkachenko
    IHEP Protvino, Protvino, Moscow Region
  • A.V. Kuzmin, M.A. Tiunov
    BINP SB RAS, Novosibirsk
  • F. Zimmermann
    CERN, Geneva
  Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy.

The 2nd Tevatron electron lens (TEL2) is under the final phase of development and prepare for the installation in the Tevatron. In this report, we will describe the system and the main upgrades from the TEL1. We will also show the magnetic field measurement results, beam testing and plan for installation. The special operation consideration of the TEL2 under high radiation dose will also be discussed.

 
 
WPAE045 Progress on RF Coupling Coil Module Design for the MICE Channel vacuum, coupling, factory, superconductivity 2869
 
  • D. Li, M.A. Green, S.P. Virostek, M.S. Zisman
    LBNL, Berkeley, California
  • W. Lau, A. E. White, S.Q. Yang
    OXFORDphysics, Oxford, Oxon
  Funding: This research work is supported by the US Department of Energy, under Contract No. DE-AC03-76SF00098.

We describe the progress on the design of the RF coupling coil (RFCC) module for the international Muon Ionization Cooling Experiment (MICE) at Rutherford Appleton Laboratory (RAL) in the UK. The MICE cooling channel design consists of two SFOFO cells that is similar to that of the US Study-II of a neutrino factory. The MICE RFCC module comprises a superconducting solenoid, mounted around four normal conducting 201.25-MHz RF cavities. Each cavity has a pair of thin curved beryllium windows to close the conventional open beam irises, so thatnecessitating separate power feeds for each of the four cavities has to be separately powered. The coil package that surrounds the RF cavities sits is mounted on a vacuum vessel. The RF vacuum is shared between the cavities and the vacuum vessel around the cavities such that. Therefore there is no differential pressure on the thin beryllium windows. This paper discusses the design progress of the RFCC module, the fabrication progress of a prototype 201.25-MHz cavity, and the superconducting coupling coil that will be cooled using a single, small 4 K cooler.

 
 
WPAP001 HELIOS, the Linac Injector of SOLEIL: Installation and First Results linac, gun, electron, klystron 755
 
  • B. Pottin, R. Chaput, J.-P. Pollina, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette
  • D. Jousse, J.-L. Pastre, A.S. Setty
    THALES, Colombes
  Funding: SOLEIL

HELIOS is the Hundred MeV Electron Linac Injector Of SOLEIL the new French SR facility. The Linac is constructed by THALES as a “turn key” equipment on the basis of SOLEIL’s APD design. The Linac injector is composed of a triode gun (90 kV, 500 mA), a prebuncher (10 kV, 200 W), a buncher (SW, 15 MeV, 5 MW) focalised by a solenoid and two accelerating sections (TW, 2pi/3, 45 MeV, 12 MW) feeded by 2 klystrons (35 MW). The major Linac components have been previously tested at THALES factory and the installation on the site has begun from October 2004. After a brief description of the building construction, the tests of the Linac components and operating modes will be detailed. The commissioning with beam is planned on March; the results on beam qualities will be presented: energy spread, emittance, and beam dynamics along the Linac.

 
 
WPAP003 Emission Mechanisms in a Photocathode RF Gun electron, cathode, laser, gun 856
 
  • J.H. Han, J.W. Baehr, H.-J. Grabosch, M. Krasilnikov, V. Miltchev, A. Oppelt, B. Petrosyan, S. Riemann, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • K. Floettmann, S. Schreiber
    DESY, Hamburg
  • M.V. Hartrott
    BESSY GmbH, Berlin
  • P. Michelato, L. Monaco, D. Sertore
    INFN/LASA, Segrate (MI)
  • J.R. Roensch
    Uni HH, Hamburg
  In photocathode rf guns, emission mechanisms at the photocathode play a crucial role in the overall beam dynamics. A low bunch charge as well as a short Gaussian bunch profile allow us to study the beam dynamics depending on emission phase without space charge force. This paper presents experimental and simulation studies toward detailed understanding of the photo emission and secondary emission processes at the cathode.  
 
WPAP006 Recent Developments at PITZ laser, booster, gun, electron 1012
 
  • M. Krasilnikov, K. Abrahamyan, G. Asova, J.W. Baehr, G. Dimitrov, U. Gensch, H.-J. Grabosch, J.H. Han, S. Khodyachykh, S. Liu, V. Miltchev, A. Oppelt, B. Petrosyan, S. Riemann, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • W. Ackermann, W.F.O. Müller, S. Schnepp, T. Weiland
    TEMF, Darmstadt
  • J.-P. Carneiro, K. Floettmann, S. Schreiber
    DESY, Hamburg
  • M.V. Hartrott, E. Jaeschke, D. Kraemer, D. Lipka, R. Richter
    BESSY GmbH, Berlin
  • P. Michelato, L. Monaco, C. Pagani, D. Sertore
    INFN/LASA, Segrate (MI)
  • J.R. Roensch, J. Rossbach
    Uni HH, Hamburg
  • W. Sandner, I. Will
    MBI, Berlin
  • I. Tsakov
    INRNE, Sofia
  The ability to produce high brightness electron beams as required for modern Free Electron Lasers (FELs) has been demonstrated during the first stage of the Photo Injector Test Facility at DESY Zeuthen (PITZ1). The electron source optimization at PITZ1 was successfully completed, resulting in the installation of the PITZ rf gun at the VUV-FEL (DESY, Hamburg). One of the main goals of the second stage of PITZ (PITZ2) is to apply higher gradients in the rf gun cavity in order to obtain smaller beam emittance by faster acceleration of the space charge dominated beams. In order to reach the required gradients a 10 MW klystron has to be installed and the gun cavity has to be conditioned for higher peak power. Another important goal of PITZ2 is a detailed study of the emittance conservation principle by using proper electron beam acceleration with a booster. Further photo injector optimization, including update of the photocathode laser and diagnostic tools, is foreseen as well. Recent progress on the PITZ developments will be reported.  
 
WPAP009 Optimization of RF Compressor in the SPARX Injector brightness, simulation, gun, bunching 1144
 
  • C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • M. Boscolo, M. Ferrario, B. Spataro
    INFN/LNF, Frascati (Roma)
  • L. Serafini
    INFN-Milano, Milano
  The SPARX photoinjector consists in a rf gun injecting into three SLAC accelerating sections, the first one operating in the RF compressor configuration in order to achieve higher peak current. A systematic study based on PARMELA simulations has been done in order to optimize the parameters that influence the compression also in view of the application of this system as injector of the so called SPARXINO 3-5 nm FEL test facility. The results of computations show that peak currents at the injector exit up to kA level are achievable with a good control of the transverse and longitudinal emittance by means of a short SW section operating at 11424 MHz placed before the first accelerating section. Some working points in different compression regimes suitable for FEL experiments have been selected. The stability of these points and the sensitivity to various types of random errors are discussed.  
 
WPAP011 SPARC Working Point Optimization for a Bunch with Gaussian Temporal Profile radiation, simulation, electron, undulator 1248
 
  • M. Boscolo, M. Ferrario, V. Fusco, M.  Migliorati
    INFN/LNF, Frascati (Roma)
  • S. Reiche
    UCLA, Los Angeles, California
  • C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  We present the optimization of the working point for the SPARC photoinjector with a Gaussian temporal profile. The implications of a Gaussian temporal profile are discussed here for the standard working conditions and for the RF compressor case in comparison with the nominal working point performances of a 10ps flat top pulse with rise time of 1ps. Comparisons with the upgraded version of the HOMDYN code including arbitrary bunch temporal profiles are also reported. Advantages and drawbacks of the Gaussian and flat top pulse shapes are discussed. For the standard working point, it is shown that the two cases provide the same saturation length and average power, but the higher current in the beam core of the Gaussian pulse gives a higher peak radiation power. As the laser pulse shape could be Gaussian at the first stage of the SPARC operation, it is clear the importance of these simulation results.  
 
WPAP012 Preliminary Results on Beam Dynamics of Laser Pulse Shaping Effects in SPARC laser, electron, simulation, target 1315
 
  • M. Boscolo, M. Ferrario, M.  Migliorati
    INFN/LNF, Frascati (Roma)
  • F. Castelli, S. Cialdi, A.F. Flacco
    INFN-Milano, Milano
  In a photoinjector system the role played by the laser pulse shaping in achieving high quality electron beam is crucial, as it determines the distribution dependent space charge effects in the early stages of the acceleration. A dedicated code to simulate pulse shaping in a laser system and able to generate the corresponding initial electron beam distribution has been developed. Realistic deviations from the ideal flat top pulse give for example a ramp or multi-peaks shape with a raletive rise time, plateau deformation and ripples. The beam dynamics of electron beams with different initial temporal pulse characteristics along the SPARC photoinjector has also been studied with the code PARMELA. More exotic pulse shaping are also discussed. The study presented here gives some indications on the tolerances of the laser beam characteristics for the electron beam quality preservation.  
 
WPAP017 Experimental Observation of a 100-Femtosecond Single Electron Bunch in Photocathode Linac with Longitudinal Emittance Compensation Technique electron, linac, gun, cathode 1546
 
  • J. Yang
    RCNP, Osaka
  • K. Kan, T. Kondoh, T. Kozawa, S. Tagawa, Y. Yoshida
    ISIR, Osaka
  The realization of a 100fs electron pulse is important for the studies of ultrafast physical/chemical phenoena with a pump-probe method. We have developed a photocathode linear accelerator (linac) to generate such electron pulse with a magnetic pulse compressor. The nonlinear effect of the magnetic fields in the pulse compression was compensated carefully by optimizing the magnetic fields and the booster linac RF phase. A 105fs(rms) electron bunch with electron charge of 0.1nC was observed experimentally by using a femtosecond streak camera. The beam energy was 35MeV, and the normalized teraservers emittance was lower than 3mm-mrad. The dependences of the pulse length and the emittance on the electron charge were also measured and compared with the theoretical calculations.  
 
WPAP018 Generation of Double-Decker Femtosecond Electron Beams in a Photoinjector electron, linac, gun, laser 1604
 
  • J. Yang, K. Kan, T. Kondoh, T. Kozawa, Y. Kuroda, S. Tagawa, Y. Yoshida
    ISIR, Osaka
  The femtosecond electron beam is a practical source in the pump-probe experiment for studies of ultrafast physical/chemical reactions in materials, in which a mode-locked ultrashort laser light is used as a probe source. The synchronized time jitter between the electron beam and the laser light limits the time resolution in the experiment. In order to reduce the time jitter, a new concept of synchronized double-decker electron beam generation in a photoinjector was proposed. The double electron beams were observed in an S-band photocathode RF gun by injecting two laser beams which produced with a picosecond laser. The double electron beams were compressed into 400fs(rms) with a phase-space rotation technique in magnetic fields. The beams, which one is used as a pump source and another is used as a probe source, are expected for ultrafast reaction studies in femtosecond resolution.  
 
WPAP019 X-Band Thermionic Cathode RF Gun at UTNL gun, cathode, scattering, linac 1646
 
  • A. Fukasawa, F. Ebina, T. Kaneyasu, H. Ogino, F. Sakamoto, M. Uesaka
    UTNL, Ibaraki
  • M. Akemoto, H. Hayano, T. Higo, J.U. Urakawa
    KEK, Ibaraki
  • K. Dobashi
    NIRS, Chiba-shi
  • K.M. Matsuo, H. Sakae
    IHI/Yokohama, Kanagawa
  The X-band (11.424 GHz) linac for compact Compton scattering hard X-ray source are under construction at Nuclear Engineering Research Laboratory, University of Tokyo. This linac designed to accelerate up to 35 MeV, and this electron beam will be used to produce hard X-ray by colliding with laser. It consists of a thermionic cathode RF gun, an alpha magnet, and a traveling wave tube. The gun has 3.5 cells (unloaded Q is 8250) and will be operated at pi-mode. A dispenser cathode is introduced. Since the energy spread of the beam from the gun is predicted to be broad due to the continuous emission from the thermionic cathode, a slit is placed in the alpha magnet to eliminate low energy electrons. The simulation on the injector shows the beam energy 2.9 MeV, the charge 23 pC/bunch, and the emittance less than 10 mm.mrad. The experiment on the gun is planed in the beginning of 2005, and the details will be discussed on the spot.  
 
WPAP021 Status of PPI (Pohang Photo-Injector) for PAL XFEL gun, cathode, electron, laser 1733
 
  • S.J. Park, C. Kim, I.S. Ko, J.-S. Oh, Y.W. Parc, P.C.D. Park, J.H. Park
    PAL, Pohang, Kyungbuk
  • X.J. Wang
    BNL, Upton, Long Island, New York
  Funding: Supported by the POSCO and the MOST, Korea.

A X-Ray Free Electron Laser (XFEL) project based on the Self-Amplified Spontaneous Emission (SASE) is under progress at the Pohang Accelerator Laboratory (PAL). One of the critical R&D for the PAL XFEL* is to develop the Pohang Photo-Injector (PPI) which is required to deliver electron beams with normalized emittance < 1.5 mm-mrad. In order to achieve the required beam quality with high stability and reliability, we will use photocathode with quantum efficiency > 0.1 % and long lifetime. This will greatly lessen the laser energy requirement for producing flat-top UV pulses, and open the possibility of using only regenerative amplifiers (RGAs) to drive the photocathode RF gun. The RGAs can produce mJs output with much better stability than multi-pass amplifiers. Both the Cs2Te and Mg are under consideration for the possible photo-cathode. To demonstrate the suitability of the Mg and Cs2Te for the future 4th generation light source application, an improved BNL-type S-band RF gun with a high-performance load-lock system will be developed for the PPI. In this article, we present the design concept of the PPI, the expected performance, and report on its development status.

*J.S. Oh, S.J. Park et al., "0.3-nm SASE-FEL at PAL," NIM A528, 582 (2004); S.J. Park, J.S. Oh et al., "Design Study of Low-Emittance Injector for SASE XFEL at Pohang Accelerator Laboratory," FEL2004, Italy, 2004.

 
 
WPAP022 Measurements of Transverse Emittance for RF Photocathode Gun at the PAL laser, gun, booster, cathode 1760
 
  • J.H. Park, I.S. Ko, J.-S. Oh, Y.W. Parc, S.J. Park
    PAL, Pohang, Kyungbuk
  • X.J. Wang
    BNL, Upton, Long Island, New York
  • D. Xiang
    TUB, Beijing
  Funding: Supported by the POSCO and the MOST, Korea.

A BNL GUN-IV type RF photo-cathode gun is under fabrication for use in the FIR (Far Infra-Red) facility being built at the Pohang Accelerator Laboratory (PAL). Performance test of the gun will include the measurement of transverse emittance profile along the longitudinal direction. Successful measurement of the emittance profile will provide powerful tool for the commissioning of the 4GLS (4th generation light source) injectors based on the emittance compensation principle. We are going to achieve this withthe use of pepper-pot based emittance meters that can be moved along the longitudinal direction. In this article, we present design considerations on the emittance meter with the resolution of 1 mm mrad.

 
 
WPAP031 Use of Multiobjective Evolutionary Algorithms in High Brightness Electron Source Design gun, laser, electron, cathode 2188
 
  • I.V. Bazarov, C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  • I. Senderovich
    Cornell University, Ithaca, New York
  Funding: Supported by Cornell University.

We describe the use of multiobjective evolutionary algorithms (MOEAs) for the design and optimization of a high average current, high brightness electron injector for an Energy Recovery Linac (ERL). By combining MOEAs with particle tracking, including space charge effects, and by employing parallel computing resources, we explored a multidimensional parameter space with 22 independent variables for a DC gun based injector which is being constructed at Cornell University. The simulated performance of the optimized injector is found to be excellent, with normalized rms emittances as low as 0.1 mm-mrad for a 77 pC bunch, and 0.7 mm-mrad for a 1 nC bunch. We detail the advantages and flexibility of MOEAs as a powerful tool well suited for wide application in solving various problems in the accelerator field.

 
 
WPAP033 State-of-the-Art Electron Guns and Injector Designs for Energy Recovery Linacs (ERL) gun, booster, cathode, electron 2292
 
  • A.M.M. Todd, A. Ambrosio, H. Bluem, V. Christina, M.D. Cole, M. Falletta, D. Holmes, E. Peterson, J. Rathke, T. Schultheiss, R. Wong
    AES, Princeton, New Jersey
  • I. Ben-Zvi, A. Burrill, R. Calaga, P. Cameron, X.Y. Chang, H. Hahn, D. Kayran, J. Kewisch, V. Litvinenko, G.T. McIntyre, T. Nicoletti, J. Rank, T. Rao, J. Scaduto, K.-C. Wu, A. Zaltsman, Y. Zhao
    BNL, Upton, Long Island, New York
  • S.V. Benson, E. Daly, D. Douglas, H.F.D. Dylla, L. W. Funk, C. Hernandez-Garcia, J. Hogan, P. Kneisel, J. Mammosser, G. Neil, H.L. Phillips, J.P. Preble, R.A. Rimmer, C.H. Rode, T. Siggins, T. Whitlach, M. Wiseman
    Jefferson Lab, Newport News, Virginia
  • I.E. Campisi
    ORNL, Oak Ridge, Tennessee
  • P. Colestock, J.P. Kelley, S.S. Kurennoy, D.C. Nguyen, W. Reass, D. Rees, S.J. Russell, D.L. Schrage, R.L. Wood
    LANL, Los Alamos, New Mexico
  • D. Janssen
    FZR, Dresden
  • J.W. Lewellen
    ANL, Argonne, Illinois
  • J.S. Sekutowicz
    DESY, Hamburg
  • L.M. Young
    TechSource, Santa Fe, New Mexico
  Funding: This work is supported by NAVSEA, NSWC Crane, the Office of Naval Research, the DOD Joint Technology Office and by the U.S. DOE.

A key technology issue of ERL devices for high-power free-electron laser (FEL) and 4th generation light sources is the demonstration of reliable, high-brightness, high-power injector operation. Ongoing programs that target up to 1 Ampere injector performance at emittance values consistent with the requirements of these applications are described. We consider that there are three possible approaches that could deliver the required performance. The first is a DC photocathode gun and superconducting RF (SRF) booster cryomodule. Such a 750 MHz device is being integrated and will be tested up to 100 mA at the Thomas Jefferson National Accelerator Facility beginning in 2007. The second approach is a high-current normal-conducting RF photoinjector. A 700 MHz gun will undergo thermal test in 2006 at the Los Alamos National Laboratory, which, if successful, when equipped with a suitable cathode, would be capable of 1 Ampere operation. The last option is an SRF gun. A half-cell 703 MHz SRF gun capable of delivering 1.0 Ampere will be tested to 0.5 Ampere at the Brookhaven National Laboratory in 2006. The fabrication status, schedule and projected performance for each of these state-of-the-art injector programs will be presented.

 
 
WPAP035 Emittance Compensation in Flat Beam Production in an RF Gun Linac space-charge, electron, simulation, gun 2399
 
  • S. Wang
    ANL, Argonne, Illinois
  Funding: This research is supported by the U.S. Department of Energy under contract DE-FG02-92ER40747 and the National Science Foundation under contract NSF PHY-0244793.

Ya. Derbenev Proposed a flat beam production method in RF gun Linac, which passes the electron beam through a matched skew quadrupole channel and transform the initially transversely round beam into a flat beam. Fermilab/NICADD Photoinjector Laboratory has performed a lot of experiments, a ratio of 50 of the transverse emittances in x and y plane has been achieved and the ratio of 100 and higher is underway of research. In this paper, the S-shaped flat beam, found both in experiments and simulations, is investigated. The nonlinear transverse force from the RF field when the beam passes the superconducting cavity is found to be one of the sources which produce the transverse S-shape distribution and increase the emittance. An extra solenoid located before the superconducting cavity is proposed to be added to adjust the beam transverse size when the beam passes through the cavity. The resulted transverse nonlinear space-charge force is used to counter-act against the nonlinear transverse force from the RF field. PARMELA simulations have shown that, with proper setup of the extra solenoid, the emittance ratio can be enhanced by a factor of 2 and the S-shaped transverse distribution can also be eliminated.

 
 
WPAP036 Determination of the Field Enhancement Factor on Photocathode Surface Via the Schottky Effect laser, cathode, photon, electron 2425
 
  • Z.M. Yusof, M.E. Conde, W. Gai
    ANL, Argonne, Illinois
  Funding: U.S. Department of Energy.

Using photons with energy that is less than the work function, we employ the Schottky effect to determine the field enhancement factor on the surface of a Mg photocathode. The Schottky effect is manifested via a shift in the threshold for photoemission as the amplitude of the RF in the photoinjector gun is varied. From the threshold condition, we can directly determine the field enhancement factor on the cathode surface. This is a viable technique to obtain the field enhancement factor of surfaces of other materials such as Nb and Cu.

 
 
WPAP037 Novel Method of Emittance Preservation in ERL Merging System in Presence of Strong Space Charge Forces electron, space-charge, gun, linac 2512
 
  • D. Kayran, V. Litvinenko
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy and partially funded by the US Department of Defence

Energy recovery linacs (ERLs) are potential candidates for the high power and high brightness electron beams sources. The main advantages of ERL are that electron beam is generated at relatively low energy, injected and accelerated to the operational energy in a ERL loop with a common linac, then is decelerated in the same loop down to injection energy and dumped. The intrinsic part of any ERL is a merging system for the low-energy beam with a high-energy beam passing around the ERL loop. One of the challenges for generating high charge high brightness e-beam in ERL is development of merging system, which provides achromatic condition for space charge dominated beam and which is compatible with the emittance compensation scheme. In this paper we present principles of operation of such merging system. We also describe an example of such system, which we call Zigzag or Z-system. We use a specific implementation for R&D ERL at Brookhaven for illustration.

 
 
WPAP043 Production of Transverse Controllable Laser Density Distribution in Fermilab/NICADD Photoinjector laser, electron, simulation, space-charge 2783
 
  • J.L. Li, J.L. Li
    Rochester University, Rochester, New York
  • P. Piot, R. Tikhoplav
    Fermilab, Batavia, Illinois
  The Fermilab/NICADD photoinjector laboratory consist of a photoemission electron source based on an L band rf-gun. The CsTe photocathode is illuminated by an ultrashort UV laser. The transport line from the laser to the photocathode was recently upgraded to allow imaging of an object plane located ~20 m from the photocathode. This upgrade allows the generation of transverse laser distributions with controlled nonuniformity, yielding the production of an electron beam with various transverse densities patterns. Measuring the evolution of the artificial pattern on the electron bunch provides information that can be used to benchmark numerical simulations and investigate the impact of space charge. Preliminary data on these investigations are presented in the present paper.  
 
WPAP049 A High-Gradient CW RF Photo-Cathode Electron Gun for High Current Injectors cathode, gun, ion, coupling 3049
 
  • R.A. Rimmer
    Jefferson Lab, Newport News, Virginia
  Funding: This manuscript has been authored by SURA, Inc. under Contract No. DE-AC05-84ER-40150 with the U.S. Department of Energy.

The paper describes the analysis and preliminary design of a high-gradient photo-cathode RF gun optimized for high current CW operation. The gun cell shape is optimized to provide maximum acceleration for the newly emitted beam while minimizing wall losses in the structure. The design is intended for use in future high-current high-power CW FELs but the shape optimization for low wall losses may be advantageous for other applications such as XFELs or Linear Colliders using high peak power low duty factor guns where pulse heating is a limitation. The concept allows for DC bias on the photocathode in order to repel ions and improve cathode lifetime.

 
 
WPAP055 A 3D Parallel Beam Dynamics Code for Modeling High Brightness Beams in Photoinjectors space-charge, simulation, cathode, brightness 3316
 
  • J. Qiang, S.M. Lidia, R.D. Ryne
    LBNL, Berkeley, California
  • C. Limborg-Deprey
    SLAC, Menlo Park, California
  Funding: This work was supported by a SciDAC project in accelerator physics which is supported by the U.S. DOE/SC Office of High Energy Physics and the Office of Advanced Scientific Computing Research.

In this paper we report on IMPACT-T, a 3D beam dynamics code for modeling high brightness beams in photoinjectors and rf linacs. IMPACT-T is one of the few codes used in the photoinjector community that has a parallel implementation, making it very useful for high statistics simulations of beam halos and beam diagnostics. It has a comprehensive set of beamline elements, and furthermore allows arbitrary overlap of their fields. It is unique in its use of space-charge solvers based on an integrated Green function to efficiently and accurately treat beams with large aspect ratio, and a shifted Green function to efficiently treat image charge effects of a cathode. It is also unique in its inclusion of energy binning in the space-charge calculation to model beams with large energy spread. Together, all these features make IMPACT-T a powerful and versatile tool for modeling beams in photoinjectors and other systems. In this paper we describe the code features and present results of IMPACT-T simulations of the LCLS and LUX photoinjectors. We also include a comparison of IMPACT-T and PARMELA results, and a comparison of IMPACT-T and ASTRA results.

 
 
WPAP057 Three-Dimensional Theory and Simulation of an Ellipse-Shaped Charged-Particle Beam Gun simulation, electron, vacuum, focusing 3372
 
  • R. Bhatt, T. Bemis, C. Chen
    MIT/PSFC, Cambridge, Massachusetts
  Funding: U.S. DOE: Grant No. DE-FG02-95ER40919, Grant No. DE-FG02-01ER54662, Air Force Office of Scientific Research: Grant No. F49620-03-1-0230, and the MIT Deshpande Center for Technological Innovation.

A three-dimensional (3D) theory of non-relativistic, laminar, space-charge-limited, ellipse-shaped, charged-particle beam formation has been developed recently (Bhatt and Chen, PR:ST-AB, submitted Dec. 2004), whereby charged particles (electrons or ions) are accelerated across a diode by a static voltage differential and focused transversely by Pierce-type external electrodes placed along analytically specified surfaces. The treatment is extended to consider the perturbative effects of anode hole lensing, thermal isolation of the emitter, finiteness and nonuniformities of beam-forming electrodes, and an initial thermal spread. Analytic and semi-analytic results are presented along with 3D simulations utilizing the 3D trajectory code, OMNITRAK. Considerations with regard to beam matching into a periodic magnetic focusing lattice are discussed.

 
 
ROAA004 MICE: The International Muon Ionisation Cooling Experiment instrumentation, synchrotron, coupling, optics 398
 
  • P. Drumm
    CCLRC/RAL, Chilton, Didcot, Oxon
  Muon storage rings have been proposed for use as sources of intense high-energy neutrino beams and as the basis for multi-TeV lepton-antilepton colliding beam facilities. To optimise the performance of such facilities is likely to require the phase-space compression (cooling) of the muon beam prior to acceleration and storage. The short muon-lifetime makes it impossible to employ traditional techniques to cool the beam while maintaining the muon-beam intensity. Ionisation cooling, a process in which the muon beam is passed through a series of liquid hydrogen absorbers followed by accelerating RF-cavities, is the technique proposed to cool the muon beam. The international Muon Ionisation Cooling Experiment (MICE) collaboration has been formed to carry out a muon-cooling demonstration experiment, and its proposal to Rutherford Appleton Laboratory has been approved. The MICE cooling channel, the instrumentation and the implementation at the Rutherford Appleton Laboratory is described together with the predicted performance of the channel and the measurements that will be made.  
 
ROAA005 Recent Innovations in Muon Beam Cooling and Prospects for Muon Colliders simulation, collider, 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.

 
 
RPAE001 On the Issue of Phasing of Undulators at the Advanced Photon Source undulator, brilliance, electron, radiation 764
 
  • R.J. Dejus
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Placing two collinear undulators in the 5.6-m-long straight sections at the Advanced Photon Source (APS) can answer the demand for increased brilliance. Whether longitudinal phasing needs to be taken into account for optimum spectral performance has been investigated. A comprehensive computer simulation study was completed to study the effect of the electron beam emittance, the magnetic field quality of the undulators, and the magnetic field strength (K value) on the spectral performance. For a zero-emittance beam, the radiation spectra exhibit strong interference that depends sensitively on the phase between the undulators. For a realistic APS-emittance beam and beam energy spread, the strong and phase-sensitive interference is substantially smoothed. A summary of the key findings including intensity losses due to unphased undulators is reported in this paper.

 
 
RPAE009 Design Considerations for the Stability Improvement of Klystron-Modulator for PAL XFEL linac, undulator, power-supply, feedback 1165
 
  • J.-S. Oh, Y.J. Han, I.S. Ko, W. Namkung, S.S. Park
    PAL, Pohang, Kyungbuk
  Funding: Supported by the POSCO and the MOST, Korea.

The PAL linac is planed to be converted to a SASE-XFEL facility (PAL XFEL) that supplies coherent X-rays down to 0.3-nm wavelength. PAL XEL requires a 3-GeV driver linac and a 60-m long in-vacuum undulator to realize an X-ray SASE-FEL. The linac should supply highly bright beams with emittance of 1.2 mm-mrad, a peak current of 3.5 kA, and a low energy spread of 0.03%. The RF stability of 0.06% rms is required for both RF phase and amplitude for reasonably stable SASE output. This stability is mainly determined by a klystron-modulator. Therefore present stability level of the modulator has to be improved 10 times better to get the pulse stability of 0.05%. The regulation methods such as traditional de-Q’ing and precision inverter charging technology are reviewed. Design considerations for the stability improvement of klystron-modulator for PAL XFEL are presented.

 
 
RPAE028 Lattice Upgrade Options for the ESRF Storage Ring dipole, lattice, optics, quadrupole 2047
 
  • Y. Papaphilippou, P. Elleaume, L. Farvacque, A. Ropert
    ESRF, Grenoble
  Several scenarios of lattice upgrade for the ESRF storage ring are under study. In order to minimise the cost, their design is based on the length constraints of the existing tunnel with the ID beamlines kept in place. The goal is to shrink the emittance in order to increase the undulator brilliance. The two main options are a double bend achromat structure with non-uniform field dipoles and a triple bend achromat lattice. The two scenarios are detailed and compared with respect to their linear optics solutions, correction of chromatic effects and non-linear dynamics. An attempt to reveal the horizontal effective emittance dependence on important design parameters, such as optics functions maxima, chromaticity and dynamic aperture, is also undertaken. Technological challenges concerning magnet design with small physical aperture in a reduced space are also addressed.  
 
RPAE029 Analytical Considerations for Reducing the Effective Emittance with Variable Dipole Field Strengths optics, dipole, betatron, damping 2086
 
  • Y. Papaphilippou, P. Elleaume
    ESRF, Grenoble
  The basic optics design scope in lepton rings is to match the sections in either side of the bending magnets in order to minimise the equilibrium emittance. A further important emittance reduction can be achieved by incorporating dipoles for which the deflecting field varies along the electron beam path in the magnet. The figure of merit for such lattices when used in a synchrotron light source is the minimization of the so-called effective emittance. The effective emittance is computed in the middle of the undulator straight section as the product of the rms size and divergence and therefore includes contributions from the betatron emittance and from the electron energy spread. In this paper, analytical formulas are obtained for the minimum betatron and effective emittance in arbitrary dipole fields and the associated optics function at the dipole entrance. Examples are given for specific dipole field functions and their properties with respect to the effective emittance minimisation. Finally, the effective emittance is parameterised with respect to standard cell optics properties, such as the phase advance, the maximum beta and dispersion functions and the focusing element strengths.  
 
RPAE036 Damping Wigglers for the PETRA III Light Source wiggler, damping, radiation, synchrotron 2446
 
  • M. Tischer, K. Balewski, W. Decking, M. Seidel, L. Yongjun
    DESY, Hamburg
  • V. Kuzminykh, E. Levichev, P. Vobly, K. Zolotariov
    BINP SB RAS, Novosibirsk
  Within the reconstruction of the PETRA booster ring at DESY towards a third generation light source after 2007, damping wigglers will be installed to reduce the emittance to a value of 1 nmrad. Two damping sections in the long straights of PETRA have been assigned to accommodate 20 wigglers in total. The wigglers will be permanent magnet devices with a fixed gap which are surrounded by an iron enclosure to reduce the leakage flux. Each wiggler will provide a damping integral of 4 T2m per segment and generate a synchrotron radiation power of 42 kW. A short one period long prototype has recently been built to prove the magnetic design and study the correction scheme for tuning the pole strength. The wiggler segments will be followed by an SR absorber shading the downstream quadrupole and successive wiggler segment, the accumulated on-axis power of about 200 kW will be taken up by the final absorber at the damping section end.  
 
RPAE037 Operation with a Low Emittance Optics at ANKA optics, injection, storage-ring, resonance 2467
 
  • E. Huttel, A. Ben Kalefa, I. Birkel, A.-S. Müller, P. Wesolowski
    FZK, Karlsruhe
  • M. Giovannozzi
    CERN, Geneva
  • M. Pont, F. Pérez
    CELLS, Bellaterra (Cerdanyola del Vallès)
  ANKA is a synchrotron light source operating in an energy range from 0.5 to 2.5 GeV. The electron storage ring at ANKA is designed as a variation of an eightfold Double Bend Achromat structure. Since its commissioning the facility has been operated with zero dispersion in the long straight sections resulting in an emittance of about 100 nmrad. Since mid 2004 ANKA is operated with dispersion distributed over the complete ring thus reducing the emittance to 40 nmrad. In the course of the re-design of the storage ring optics a compensation of higher order field components leads to a visibly increased momentum acceptance. Optics calculations and measurements as well as operational experience will be discussed.  
 
RPAE041 Reconstruction of Photon Factory Storage Ring for the Straight-Sections Upgrade Project quadrupole, undulator, factory, photon 2678
 
  • T. Honda, S. Asaoka, W.X. Cheng, K. Haga, K. Harada, Y. Hori, M. Izawa, T. Kasuga, Y. Kobayashi, H. Maezawa, A. Mishina, T. Mitsuhashi, T. Miyajima, H. Miyauchi, S. Nagahashi, T. Nogami, T. Obina, C.O. Pak, S. Sakanaka, Y. Sato, T. Shioya, M. Tadano, T. Takahashi, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, S. Yamamoto
    KEK, Ibaraki
  The Photon Factory (PF) storage ring is a 2.5-GeV synchrotron light source at KEK. In 1997, we have accomplished a large reconstruction of the ring in order to reduce the beam emittance from 130 nm rad to 36 nm rad. After the reconstruction, the PF ring has continued a stable operation over 5000 hours a year. Now we are proceeding with another upgrade project to create four new straight sections and to largely lengthen the existing 10 straight sections. The shutdown for the upgrade project is scheduled for the period March-September 2005. The lattice configuration around the straight sections will be modified by replacing quadrupole magnets with new shorter ones and by placing them closer to the near-by bending magnets. Simultaneously the beam duct in two thirds of the storage ring will be replaced. Due to this modification of the lattice, the practical emittance will be reduced to 27 nm rad. The new straight sections will have low beta functions and suitable for housing short-period narrow-gap undulators. The in-vacuum undulators, which have a sufficiently high brilliance within a spectral range from 8 to 16 keV, are being developed now.  
 
RPAE044 Operation and Recent Developments of the Photon Factory Advanced Ring injection, single-bunch, vacuum, betatron 2845
 
  • T. Miyajima, T. Abe, W.X. Cheng, K. Ebihara, K. Haga, K. Harada, Y. Hori, T. Ieiri, S. Isagawa, T. Kageyama, T. Kasuga, T. Katoh, H. Kawata, M. Kikuchi, Y. Kobayashi, K. Kudo, T. Mitsuhashi, S. Nagahashi, T.T. Nakamura, H. Nakanishi, T. Nogami, T. Obina, Y. Ohsawa, M. Ono, T. Ozaki, H. Sakai, Y. Sakamoto, S. Sakanaka, M. Sato, M. Satoh, T. Shioya, M. Suetake, R. Sugahara, M. Tadano, T. Takahashi, S. Takasaki, Y. Tanimoto, M. Tejima, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, N. Yamamoto, S. Yamamoto, S.I. Yoshimoto
    KEK, Ibaraki
  The Photon Factory Advanced Ring (PF-AR) is a synchrotron light source dedicated to X-ray research. The PF-AR is usually operated at a beam energy of 6.5 GeV, but a 5.0 GeV mode is also available for medical application. In 6.5 GeV mode the typical lifetime of 15 hrs and the beam current of 60 mA with a single-bunch have been archived. Almost full-time single-bunch operation for pulse X-ray characterize the PF-AR. However, single-bunch high-current caused several problems to be solved, including the temperature rise of the some of the vacuum component, a pressure increase in the ring, and a sudden drop in lifetime. In order to avoid these issues the developments of new methods have been continued. In this paper, the status and the recent developments of the PF-AR will be presented. It concerns: the successful operation with two-bunch high-current in 5.0 GeV mode; varying the vertical beam size for the medical application; modulating the RF acceleration phase in order to elongate the length of bunch; stabilizing temperature in the ring tunnel; the study for medium emittance operation with 160 nmrad; moving the RF cavities in order to install a new insertion device; an innovative injection scheme using a pulsed quadrupole magnet.  
 
RPAE047 Lattice Study for the Taiwan Photon Source dynamic-aperture, sextupole, lattice, photon 2989
 
  • C.-C. Kuo, H.-P. Chang, C.-T. Chen, G.-H. Luo, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
  The feasibility study for the new 3.0~3.3 GeV Taiwan synchrotron light source, dubbed Taiwan Photon Source, was initiated in July, 2004. The goal is to construct a high performance light source with extremely bright X-ray in complementary to the existing 1.5 GeV light source in Taiwan. The ring circumference is 518.4 m and a 24-cell DBA lattice structure is chosen. The natural emittance with distributed dispersion is less than 2 nm-rad. A large booster ring of 499.2 m sharing the storage ring tunnel will be adopted.  
 
RPAE048 Design Consideration of a Booster for Taiwan Photon Source booster, lattice, storage-ring, synchrotron 2992
 
  • G.-H. Luo, H.-P. Chang, C.-C. Kuo, K.-K. Lin, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
  After more than 10 years' operation and expansion, the Taiwan Light Source (TLS) of National Synchrotron Radiation Research Center (NSRRC) reaches very stable operation condition. The storage ring has better than 96% of beam availability annually with 6 Insertion Devices (ID) in a six-folds symmetry over-crowded machine. Two superconducting IDs and one superconducting RF cavity were installed in recent year, which intend to push the photon energy to hard x-ray regime and double the photon flux with better beam quality. Beamlines and experimental stations occupied all over the experimental area. The uproar for more beamlines in higher photon energy with higher brightness was frequently transpired from users' community. The Board of Trustee of NSRRC gave a green light to a new design and construction of median-energy light source, Taiwan Photon Source (TPS) in the coming decade. This paper will present two draft designs of booster and the consideration of the design criteria for new booster to work with a top-up injected and very low-emittance storage ring.  
 
RPAE050 Status of the CAMD Light Source quadrupole, lattice, wiggler, diagnostics 3103
 
  • V.P. Suller
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • E.J. Anzalone, M.G. Fedurin, P. Jines, D.J. Launey, T.A. Miller, Y. Wang
    LSU/CAMD, Baton Rouge, Louisiana
  With the increasing diversity of its research program, the CAMD Light Source has improved its beam brightness and quality. Using a well calibrated model of the lattice, the ring optic has been refined to generate a lower beam emittance of 150 nm.rad and this has been confirmed by measuring the beta values with the modulated quadrupole shunt system. The beam sizes have also been measured with an X-ray pinhole camera and compared to the calculated emittance. The beam orbit is corrected to a standard position referenced to the quadrupole centers to a precision better than 0.5 mm, using a suite of well localized bumps which can also flexibly steer the user photon beams to their requirements. Beam reliability has been improved by bringing into use a VME control system for the energy ramp.  
 
RPAE057 Dynamic Aperture Optimization for Low Emittance Light Sources lattice, sextupole, dipole, quadrupole 3378
 
  • S.L. Kramer, J. Bengtsson
    BNL, Upton, Long Island, New York
  Funding: Under Contract with the United States Department of Energy Contract Number DE-AC02-98CH10886.

State of the art low emittance light source lattices, require small bend angle dipole magnets and strong quadrupoles. This in turn creates large chromaticity and small value of dispersion in the lattice. To counter the high chromaticity strong sextupoles are required which limit the dynamic aperture. Traditional methods for expanding the dynamic aperture use harmonic sextupoles to counter the tune shift with amplitude. This has been successful up to now, but is non-deterministic and limited as the sextupole strength increases, driving higher order nonlinearities. We have taken a different approach that makes use of the tune flexibility of a TBA lattice to minimize the lowest order nonlinearities, freeing the harmonic sextupoles to counter the higher order nonlinearities. This procedure is being used to improve the nonlinear dynamics of the NSLS-II lattice.

 
 
RPAE058 NSLS-II Injection Concept injection, linac, booster, storage-ring 3408
 
  • T.V. Shaftan, A. Blednykh, S. Chouhan, E.D. Johnson, S.L. Kramer, S. Krinsky, J.B. Murphy, I.P. Pinayev, S. Pjerov, B. Podobedov, G. Rakowsky, J. Rose, T. Tanabe, J.-M. Wang, X.J. Wang, L.-H. Yu
    BNL, Upton, Long Island, New York
  Currently the facility upgrade project is under progress at the NSLS (Brookhaven National Laboratory). The goal of NSLS-II is a 3 GeV ultra-low emittance storage ring that will provide three orders of magnitude increase in brightness over the present NSLS X-ray beamlines. The low emittance of the high brightness ring lattice results in quite short lifetimes, which makes operation in top-off injection mode a necessity. The NSLS-II injection system must be able to provide an electron beam at the high repetition rate and with good injection efficiency. In this paper we present a concept of the NSLS-II injection system and discuss conditions and constraints for the injector design. Various injection system parameters are estimated from the point of view of SR user demand.  
 
RPAE070 Recent Developments at Aladdin insertion, insertion-device, undulator, linac 3813
 
  • K. Jacobs, J. Bisognano, R.A. Bosch, D. Eisert, M.V. Fisher, M.A. Green, R.G. Keil, K. J. Kleman, R.A. Legg, G.C. Rogers, J.P. Stott
    UW-Madison/SRC, Madison, Wisconsin
  Funding: Work supported by the U.S. NSF under Award No. DMR-0084402.

Following on the success of lower emittance operation at 800 MeV, SRC is pursuing a number of additional enhancements to the performance of the Aladdin storage ring. Work on Aladdin has included development of low emittance lattices at 1 GeV, which will maximize the capabilities of a recently installed spectromicroscopy beamline and a proposed high-resolution keV beamline. Installation of one-meter long insertion devices in the short straight sections within the quadrant arcs of the four sided storage ring is being considered to increase the number of undulator beamlines from four to possibly eight. Studies have been made to determine what is the minimum insertion device gap that does not interfere with nominal ring operation (injection, ramping, and lifetime at full energy), and indicate that smaller-gapped devices for higher photon energy are reasonable. Lifetime increases or further emittance reductions appear possible with modest aperture increases at a small number of points on the ring. Finally, planning is under way for long term projects such as a new injector or a next generation VUV/soft-xray source for the Midwest. Details will be presented.

 
 
RPAE072 Simulations of X-Ray Slicing and Compression Using Crab Cavities in the Advanced Photon Source sextupole, photon, radiation, synchrotron 3886
 
  • M. Borland, V. Sajaev
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

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

 
 
RPAE084 Beam Dynamics Aspects of the ASP Booster closed-orbit, booster, synchrotron, injection 4150
 
  • S. Friis-Nielsen, S.P. Møller
    Danfysik A/S, Jyllinge
  In the present contribution, beam dynamics aspects of the 3 GeV ASP booster designed and produced by Danfysik A/S are presented. The booster synchrotron, based on a lattice with combined-function magnets, will have a very small emittance of around 30 nm. The dynamical aperture (and admittance) of the booster has been investigated with tracking, and results for different tunes and chromaticities will be presented. Also the reduction in admittance caused by alignment errors of the magnets will be discussed. The nominal tunes and chromaticities are mainly determined by the combined-function magnets to (9.20, 3.25) and (1,1), respectively. Using the trim quadrupoles and sextupoles, the tunes can be adjusted in the ranges (9.05-9.45, 3.05-3.45) and the chromaticities in the range (0-2, 0-2).  
 
RPAP022 A Study of Storage Ring Requirements for an Explosive Detection System Using NRA Method proton, storage-ring, target, lattice 1790
 
  • T.-S. F. Wang, J. T. Kwan
    LANL, Los Alamos, New Mexico
  Funding: US Department of Energy

The technical feasibility of an explosives detection system based on the nuclear resonance absorption (NRA) of gamma rays in nitrogen-rich materials was demonstrated at Los Alamos National Laboratory (LANL) in 1993 by using an RFQ proton accelerator and a tomographic imaging prototype.* The study is being continued recently to examine deployment of such an active interrogation system in realistic scenarios. The approach is to use a cyclotron and electron-cooling-equipped storage rings(s) to provide the high quality and high current proton beam needed in a practical application. In this work, we investigate the storage ring requirements for a variant of the airport luggage inspection system considered in the earlier LANL experiments. Estimations are carried out based on the required inspection throughput, the gamma ray yield, the proton beam emittance growth due to scattering with the photon-production target, beam current limit in the storage ring, and the electron cooling rate. Studies using scaling and reasonable parameter values indicate that it is possible to use no more than a few storage rings in a practical NRA luggage inspection system.

*R. E. Morgado et al., SPIE Conf. Proc. 2092, International Society for Optical Engineering, Bellingham, WA, 1993, p. 503.

 
 
RPAP034 Use Recirculator "SALO" in the Mode of the Neutron Source target, electron, alignment, injection 2354
 
  • I.S. Guk, A. Dovbnya, S.G. Kononenko, F.A. Peev, A.S. Tarasenko
    NSC/KIPT, Kharkov
  • J.I.M. Botman, M.J. Van der Wiel
    TUE, Eindhoven
  The opportunity of use developed in NSC KIPT recirculator SALO* with superconducting accelerating structure TESLA for reception of intensive neutron streams surveyed. As an injector it is supposed to use RF-gun with superconducting accelerating structure. An electron beam with the peak energy 130 ??? is transported on a target located apart of 100 m from recirculator. System of the focusing are designed allowing to gain on a target the required density of a beam. Tolerances on precision of an alignment of magnetooptical devices are calculated.

*I. S. Guk, A. N. Dovbnya, S. G. Kononenko, A. S. Tarasenko, M. van der Wiel, J. I. M. Botman, NSC KIPT Accelerator on Nuclear and High Energy Physics, Proceedings of EPAC 2004, Lucerne, Switzerland, p.761-764.

 
 
RPAP038 An Advantage of the Equivalent Velocity Spectroscopy for Femtsecond Pulse Radiolysis electron, laser, gun, linac 2533
 
  • T. Kondoh, T. Kozawa, S. Tagawa, T. Tomosada, J. Yang, Y. Yoshida
    ISIR, Osaka
  Funding: Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science.

For studies of electron beam induced ultra-fast reaction process, femtosecond(fs) pulse radiolysis is under construction. To realize fs time resolution, fs electron and analyzing light pulses and their jitter compensation system are needed. About a 100fs electron pulse was generated by a photocathode RF gun linac and a magnetic pulse compressor. Synchronized Ti: Sapphire laser have a puleswidth about 160fs. And, it is significant to avoid degradation of time resolution caused by velocity difference between electron and analyzing light in a sample. In the ‘Equivalent velocity spectroscopy’ method, incident analyzing light is slant toward electron beam with an angle associated with refractive index of sample. Then, to overlap light wave front and electron pulse shape, electron pulse shape is slanted toward the direction of travel. As a result of the equivalent velocity spectroscopy for hydrated electrons, using slanted electron pulse shape, optical absorption rise time was about 1.4ps faster than normal electron pulse shape. Thus, the 'Equivalent velocity spectroscopy’ is effective for femtosecond pulse radiolysis.

 
 
RPAP039 Accelerator and Ion Beam Tradeoffs for Studies of Warm Dense Matter ion, target, plasma, chromatic-effects 2568
 
  • J.J. Barnard, D. A. Callahan, A. Friedman, R.W. Lee, M. Tabak
    LLNL, Livermore, California
  • R.J. Briggs
    SAIC, Alamo, California
  • R.C. Davidson, L. Grisham
    PPPL, Princeton, New Jersey
  • E. P. Lee, B. G. Logan, P. Santhanam, A. Sessler, J.W.  Staples, J.S. Wurtele, S. Yu
    LBNL, Berkeley, California
  • C. L. Olson
    Sandia National Laboratories, Albuquerque, New Mexico
  • D. Rose, D.R. Welch
    ATK-MR, Albuquerque, New Mexico
  Funding: Work performed under the auspices of the U.S. Department of Energy under University of California contract W-7405-ENG-48 at LLNL, University of California contract DE-AC03-76SF00098 at LBNL, and contract DEFG0295ER40919 at PPPL.

One approach to heat a target to "Warm Dense Matter" conditions (similar, for example, to the interiors of giant planets or certain stages in Inertial Confinement Fusion targets), is to use intense ion beams as the heating source. By consideration of ion beam phase space constraints, both at the injector, and at the final focus, and consideration of simple equations of state, approximate conditions at a target foil may be calculated. Thus target temperature and pressure may be calculated as a function of ion mass, ion energy, pulse duration, velocity tilt, and other accelerator parameters. We examine the variation in target performance as a function of various beam and accelerator parameters, in the context of several different accelerator concepts, recently proposed for WDM studies.

 
 
RPAT001 Experimental Results of a Non-Destructive Emittance Measurement Device for H- Beams ion, laser, simulation, dipole 782
 
  • C. Gabor, H. Klein, O. Meusel, U. Ratzinger
    IAP, Frankfurt-am-Main
  • J. Pozimski
    Imperial College of Science and Technology, Department of Physics, London
  For the diagnostic of high power ion beams, non-destructive measurement devices should not only provide minimum influence on the beam itself, but also avoid various problems that occur when the high power density of the beam penetrates surfaces like slit- or pinhole plates. On the other hand, measurements of resolution should be comperable with destructive methods. Beams of negative ions offer the use of a non-destructive Emittance Measurement Instrument (EMI) based on the principle of photo detachment. Interaction of laser photons with the negative ions causes electron detachment. Due to moving the postion of the well collimated laser beam acros the ion beam the produced neutral atoms are well suited to detect the transverse beam emittance like a classical slit-grid device. After separation in a magnetic dipole, the neutrals can be viewed on a scintillator screen with a CCD camera. To investigate the use of such a photo detachment EMI and to study the transport of negative ions an experiment consisting of H minus ion source, electrostatic LEBT and EMI was constructed. The paper will present the setup of the experimental hardware and first results of measurements.  
 
RPAT013 Signal Processing for Longitudinal Parameters of the Tevatron Beam proton, antiproton, pick-up, synchrotron 1362
 
  • S. Pordes, J.L. Crisp, B.J. Fellenz, R.H. Flora, A. Para, A.V. Tollestrup
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

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

 
 
RPAT027 Tomographic Measurement of Longitudinal Emittance Growth Due to Stripping Foils ion, booster, heavy-ion, electron 2000
 
  • C. Montag, L. Ahrens, P. Thieberger
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the US Department of Energy.

During beam acceleration at the Brookhaven accelerator complex, heavy ions are stripped off their electrons in several steps. Depending on the properties of the stripping foils, this process results in an increased energy spread and therefore longitudinal emittance growth. A tomographic phase space reconstruction technique has been applied to quantify the associated emittance growth for different stripping foil materials.

 
 
RPAT031 Beam Profile Measurement with Flying Wires at the Fermilab Recycler Ring antiproton, lattice, vacuum, scattering 2182
 
  • M. Hu, R. H. Carcagno, J. Krider, E. Lorman, A. Marchionni, Y.M.P. Pischalnikov, S. Pordes, D. Slimmer, J. Wilson, J.R. Zagel
    Fermilab, Batavia, Illinois
  The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with stochastic and electron cooling systems. Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement. The following note describes the system configuration, calibration and resolution of the flying wire system, as well as analysis of the transverse beam profile in the presence of both cooling systems.  
 
RPAT033 Beta Function Measurement in the Tevatron Using Quadrupole Gradient Modulation quadrupole, coupling, lattice, dipole 2272
 
  • A. Jansson, P. Lebrun, J.T. Volk
    Fermilab, Batavia, Illinois
  Funding: Work supported by the U.S. Department of Energy.

Early in Run2, there was an effort to compare the different emittance measurements in the Tevatron (flying wires and synchtotron light) and understand the origin of the observed differences. To measure the beta function at a few key locations near the instruments, air-core quadrupoles were installed. By modulating the gradient of these magents and measuring the effect on the tune, the lattice parameters can be extracted. Initially, the results seem to disagree with with other methods. At the time, the lattice was strongly coupled due to a skew component in the main dipoles, caused by sagging of the cryostat. After a large fraction of the superconducting magnets were shimmed to remove a strong skew quadrupole component, the results now agree with expectations, confirming that the beta function is not the major error source of discrepancy in the emittance measurement.

 
 
RPAT042 Emittance Scanner Optimization for Low Energy Ion Beams ion, scattering, SNS, proton 2705
 
  • M.P. Stockli, R.F. Welton
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

Ion beam emittances are normally measured as two-dimensional distributions of the beam current fraction within a window dx centered at position coordinate x and a window dx’ centered at trajectory angle x’. Unthresholded rms emittances evaluated from experimental data are very sensitive to noise, bias, and other undesired signals. Undesired signals occur when particles from outside the measured window dx*dx’ contribute to the signal from the particles within the measured window. Increasing the window size increases the desired signal while most undesired contributions remain unchanged. However, the decreasing resolution causes an error in the emittance results, especially in the rms emittance. Using theoretical distributions we will present the tradeoff between resolution and accuracy.

 
 
RPAT051 Measurement of Dynamic Beam-Beam Effects on Horizontal Beam Size at KEKB Using SR Interferometer Equipped with Retrofocus Optics optics, simulation, beam-beam-effects, positron 3150
 
  • J.W. Flanagan, H. Fukuma, S. Hiramatsu, T. Mitsuhashi
    KEK, Ibaraki
  Transverse beam-size enlargement due to dynamic beta and beam-beam effects has been observed in the KEKB Low Energy Ring (LER) and High Energy Ring (HER). In order to observe these effects, a retrofocus optics system has been developed and installed in the horizontal SR interferometers at the HER and LER. This system allows us to vary the apparent beam size to match the dynamic range of the interferometer. We report on the retrofocus optics system and measurement results, and compare the measured effects with those expected from dynamic beta simulations.  
 
RPAT072 The General ElectroN Induced Emission (GENIE) System electron, dipole, simulation, beam-transport 3877
 
  • M.A. Epps, R. Kazimi
    Jefferson Lab, Newport News, Virginia
  • P.L. Gueye
    Hampton University, Hampton, Virginia
  A real time beam diagnostic system is proposed for the Jefferson Lab injector region. The General ElectroN Induced Emission System (GENIE) is a package that includes both hardware (beam monitoring devices) and software (for 3D or 4D visualization of the beam transport). This beam diagnostic tool relies primarily on the use of (very small) scintillating fibers placed in different planes to extract the beam profile, beam position, beam current and beam emittance in real time. Accuracies in position and angle could be at the sub- μm and μrad levels, respectively. The beam current could be reconstructed within a few percent. A combined Geant4/Parmela simulation will be developed for beam optic studies. While Parmela offers the power of beam transport with phase matching capabilities (among others), Geant4 provides the power for tracking secondary particles, as well as 3D & 4D visualization. A phase I investigation of GENIE using a 100 keV beam line is discussed in this document.  
 
RPAT080 The SPEAR 3 Diagnostic Beamlines coupling, radiation, synchrotron, optics 4057
 
  • W.J. Corbett, C. Limborg-Deprey, W.Y. Mok, A. Ringwall
    SLAC, Menlo Park, California
  Funding: Work supported in part by DOE contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.

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

 
 
RPAT086 Dual-Sweep Streak Camera Measurements of the APS User Beams storage-ring, electron, single-bunch, diagnostics 4185
 
  • A.H. Lumpkin, B.X. Yang
    ANL, Argonne, Illinois
  • F. Sakamoto
    UTNL, Ibaraki
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences under Contract Number W-31-109-ENG-38.

The Advanced Photon Source (APS) is a hard x-ray user facility based on a 7-GeV storage ring (SR). To accommodate the requests of the diverse user community, the APS normally runs with a 24-singlets fill pattern, a hybrid fill with a singlet and eight septuplets, or a 324-singlet fill pattern. In all cases the total stored beam current is 100 mA, with the lattice providing a natural emittance of about 2.5 nm rad. The first two patterns are used with a top-up mode that involves injection of one pulse of ~2.5 nC every two minutes into the designated SR bucket. Since the partition of bunch current varies for the different fills as well as the loading of the rf cavities, dual-sweep streak camera measurements (Hamamatsu model C5680) have been performed to characterize the average and individual bunch lengths in the fill patterns and the phase slew that occurs within the patterns. The bunch lengths vary from 32 ps (σ) within the septuplet to 50 ps (σ) for the singlet in the hybrid fill. The phase slew is significant in the hybrid fill across the eight septuplets. Example streak images of each pattern will be presented and discussed.

 
 
RPAT089 Advances in Optical Transition and Diffraction Radiation Emittance Diagnostics electron, simulation, optics, diagnostics 4224
 
  • R.B. Fiorito, A.G. Shkvarunets
    IREAP, College Park, Maryland
  • T. Watanabe, V. Yakimenko
    BNL, Upton, Long Island, New York
  Funding: Office of Naval Research and the DOD Joint Technology Office.

We have performed a series of experiments using Optical Transition Radiation and Optical Diffraction Radiation Interferometry to measure the two orthogonal (x,y) rms divergences of the Brookhaven National Laboratory’s Advanced Test Facility electron beam operating at an energy of 50 MeV. Measurement of the rms divergences at the (x,y) beam waist conditions, together with corresponding measurements of the rms beam sizes allows a determination of the rms x and y emittances. A comparison of the results using OTRI and ODTRI are presented.

 
 
RPAT097 2-D Low Energy Electron Beam Profile Measurement Based on Computer Tomography Algorithm with Multi-Wire Scanner electron, gun 4323
 
  • N.J. Yu, K.Y. Gong, Q. F. Li, C.-X. Tang, S. Zheng
    TUB, Beijing
  A new method for low energy electron beam profile measurement is advanced, which presents a full 2-D beam profile distribution other than the traditional 2-D beam profile distribution given by 1-D vertical and horizontal beam profiles. The method is based on the CT (Computer Tomography) algorithm. Multi-sets of data about the 1-D beam profile projections are attained by rotating the multi-wire scanner. Then a 2-D beam profile is reconstructed from these projections with CT algorithm. The principle of this method is presented. The simulation and the experiment results are compared and analyzed in detail.  
 
ROPB004 Effect of Lattice and Electron Distribution in Electron-Cloud Instability Simulations for the CERN SPS and LHC electron, lattice, dipole, simulation 387
 
  • E. Benedetto, E. Benedetto
    Politecnico di Torino, Torino
  • G. Arduini, F. Roncarolo, F. Zimmermann
    CERN, Geneva
  • B. Feng, A.F. Ghalam, T.C. Katsouleas
    USC, Los Angeles, California
  • G. Franchetti
    GSI, Darmstadt
  • K. Ohmi
    KEK, Ibaraki
  • G. Rumolo
    CELLS, Bellaterra (Cerdanyola del Vallès)
  Several simulation codes have been adapted so as to model the single-bunch electron-cloud instability including a realistic variation of the optical functions with longitudinal position. In addition, the electron cloud is typically not uniformly distributed around the ring, as frequently assumed, but it is mainly concentrated in certain regions with specific features, e.g., regions which give rise to strong multipacting or suffer from large synchrotron radiation flux. Particularly, electrons in a dipole magnet are forced to follow the vertical field lines and, depending on the bunch intensity, they may populate two vertical stripes, symmetrically located on either side of the beam. In this paper, we present simulation results for the CERN SPS and LHC, which can be compared with measurements or analytical predictions.  
 
ROPB007 3-D Parallel Simulation Model of Continuous Beam-Electron Cloud Interactions simulation, electron, betatron, synchrotron 549
 
  • A.F. Ghalam, T.C. Katsouleas
    USC, Los Angeles, California
  • E. Benedetto, F. Zimmermann
    CERN, Geneva
  • V.K. Decyk, C. Huang, W.B. Mori
    UCLA, Los Angeles, California
  • G. Rumolo
    GSI, Darmstadt
  A 3D Particle-In-Cell model for continuous modeling of beam and electron cloud interaction in a circular accelerator is presented. A simple model for lattice structure, mainly the Quadruple and dipole magnets and chromaticity have been added to a plasma PIC code, QuickPIC, used extensively to model plasma wakefield acceleration concept. The code utilizes parallel processing techniques with domain decomposition in both longitudinal and transverse domains to overcome the massive computational costs of continuously modeling the beam-cloud interaction. Through parallel modeling, we have been able to simulate long-term beam propagation in the presence of electron cloud in many existing and future circular machines around the world. The exact dipole lattice structure has been added to the code and the simulation results for CERN-SPS and LHC with the new lattice structure have been studied. Also the simulation results are compared to the results from the two macro-particle modeling for strong head-tail instability. It is shown that the simple two macro-particle model can capture some of the physics involved in the beam- electron cloud interaction qualitatively.  
 
RPPE009 Extremely High Current, High-Brightness Energy Recovery Linac electron, gun, linac, simulation 1150
 
  • I. Ben-Zvi, D.S. Barton, D.B. Beavis, M. Blaskiewicz, J.M. Brennan, A. Burrill, R. Calaga, P. Cameron, X.Y. Chang, R. Connolly, D.M. Gassner, J.G. Grimes, H. Hahn, A. Hershcovitch, H.-C. Hseuh, P.D.J. Johnson, D. Kayran, J. Kewisch, R.F. Lambiase, V. Litvinenko, G.T. McIntyre, W. Meng, T.C.N. Nehring, T. Nicoletti, B. Oerter, D. Pate, J. Rank, T. Rao, T. Roser, T. Russo, J. Scaduto, Z. Segalov, K. Smith, N.W.W. Williams, K.-C. Wu, V. Yakimenko, K. Yip, A. Zaltsman, Y. Zhao
    BNL, Upton, Long Island, New York
  • H. Bluem, A. Burger, M.D. Cole, A.J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A.M.M. Todd
    AES, Princeton, New Jersey
  • J.R. Delayen, L. W. Funk, P. Kneisel, H.L. Phillips, J.P. Preble
    Jefferson Lab, Newport News, Virginia
  Funding: Under contract with the U.S. Department of Energy, U.S. DOD Office of Naval Research and Joint Technology Office.

Next generation ERL light-sources, high-energy electron coolers, high-power Free-Electron Lasers, powerful Compton X-ray sources and many other accelerators were made possible by the emerging technology of high-power, high-brightness electron beams. In order to get the anticipated performance level of ampere-class currents, many technological barriers are yet to be broken. BNL’s Collider-Accelerator Department is pursuing some of these technologies for its electron cooling of RHIC application, as well as a possible future electron-hadron collider. We will describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun and an accelerator cavity capable of producing low emittance (about 1 micron rms normalized) one nano-Coulomb bunches at currents of the order of one ampere average.

 
 
RPPE027 High Intensity High Energy E-Beam Interacting with a Thin Solid State Target: First Results at AIRIX electron, focusing, target, scattering 1982
 
  • M. Caron, F. Cartier, D.C. Collignon, L.H. Hourdin, E. Merle, M. Mouillet, C. Noel, D.P. Paradis, O.P. Pierret
    CEA, Pontfaverger-Moronvilliers
  • O. Mouton, N. Pichoff
    CEA/DAM, Bruyères-le-Châtel
  Funding: CEA, Polygone d’Expérimentation de Morronvilliers, LEXA F-51 475 Pontfaverger (France).

AIRIX is a 2 kA, 20 MeV, 60 ns linear accelerator dedicated to X-ray flash radiography. During a regular running phase, the primary electron beam is accelerated to and focused on a high atomic number target in order to generate X-rays by brembtrahlung mainly. The huge energy density deposited into the material is such that temperature rises up to 15000°K and that clusters and particles are violently ejected from the surface. In that mechanism, the backward emission speed can reach 5 km.s-1 and the debris can gradually accumulate and subsequently contaminate some sensitive parts of the machine. In order to protect the whole accelerating line from the detrimental effect of back-ejected particles, we have investigated the technical feasibility of a thin foil implementation upstream the X-ray converter.

 
 
RPPP001 Commissioning and First Measurements on the CTF3 Chicane linac, quadrupole, vacuum, background 785
 
  • A. Ghigo, D. Alesini, G. Benedetti, C. Biscari, M. Castellano, A. Drago, D. Filippetto, F. Marcellini, C. Milardi, B. Preger, M. Serio, F. Sgamma, A. Stella, M. Zobov
    INFN/LNF, Frascati (Roma)
  • R. Corsini, T. Lefevre, F. Tecker
    CERN, Geneva
  The transfer line between the linac and the first recombination ring (Delay Loop) of the CTF3 project hs been installed at CERN in spring-summer 2004. In the transfer line a magnetic chicane is used to tune the length of the bunches coming from the linac in order to minimize the Coherent Synchrotron Radiation contribution to the beam energy spread in the recombination system. The first measurements of the beam parameters at several linac and stretcher settings are described. We report the compression curve as a function of the optical parameter R56 representing the dependence of the longitudinal position of a particle on its energy, obtained by measuring the bunch length with a 3 GHz RF deflector.  
 
RPPP005 Simulation Study of a Dogbone Damping Ring wiggler, space-charge, damping, simulation 928
 
  • Y. Ohnishi, K. Oide
    KEK, Ibaraki
  Damping ring is one of the major issues in the future linear collider (ILC). We discuss the design of the dogbone damping ring and the performance that includes dynamic apertures, space charge effects, and optics corrections.  
 
RPPP006 The PITZ Booster Cavity–A Prototype for the ILC Positron Injector Cavities booster, positron, linac, coupling 1030
 
  • V.V. Paramonov, L.V. Kravchuk
    RAS/INR, Moscow
  • K. Floettmann
    DESY, Hamburg
  • M. Krasilnikov, F. Stephan
    DESY Zeuthen, Zeuthen
  A critical issue of the design of the Positron Pre-Accelerator (PPA) for the future International Linear Collider (ILC) is the operational reliability of the normal conducting, high accelerating gradient L-band cavities. Now a booster cavity, intended for increasing the beam energy at the Photo Injector Test Facility in Zeuthen (PITZ), and developed by a joined INR-DESY group, is under construction at DESY, Hamburg. With the PITZ requirements (accelerating gradient up to 14 MV/m, rf pulse length up to 900 mks, repetition rate up to 5 Hz) this cavity, which is based on the Cut Disk Structure (CDS), is a full scale, high rf power prototype of the cavities proposed for the PPA. The booster cavity operation will allow us to confirm the main design ideas for the high gradient PPA cavities. A detailed technical study was performed during the booster cavity design, resulting in some modifications for the PPA cavities, which are described in this paper. We also propose a program of rf experiments with the PITZ booster cavity for further improvements of the PPA structures.  
 
RPPP007 CLIC Damping Ring Optics Design Studies wiggler, damping, dynamic-aperture, sextupole 1060
 
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  In this paper the nonlinearities induced by the short period NbFeB permanent wiggler optimized for the CLIC damping ring and their influence to the beam dynamics are studied.  
 
RPPP008 The Short Circumference Damping Ring Design for the ILC wiggler, damping, scattering, dynamic-aperture 1126
 
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  • K. Kubo, M. Kuriki, S. Kuroda, T. Naito, J.U. Urakawa
    KEK, Ibaraki
  • M.C. Ross
    SLAC, Menlo Park, California
  The ILC damping ring tentative design is driven by the operational scenario of the main linac, the beam-dynamics demand of producing a stable and high-quality beam, the injection/extraction scheme and the kicker performance. In this paper, a short circumference damping ring design based on TME cells is described. The ring accommodates injection kickers which provide a flat top of 280 nsec and a 60 nsec rise and fall time and very fast strip-line kickers for beam extraction with a 2 nsec rise and fall time for 3-MHz operation. The potential impact of collective effects and the possible degradation of the dynamic aperture by nonlinear-wiggler fields are estimated.  
 
RPPP009 Luminosity Tuning Bumps in the CLIC Main Linac luminosity, simulation, linac, quadrupole 1141
 
  • P. Eliasson, P. Eliasson
    Uppsala University, Uppsala
  • D. Schulte
    CERN, Geneva
  Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).

Preservation of beam emittance in the CLIC main linac is a challenging task. This requires not only beam-based alignment of the beam line components but also the use of emittance tuning bumps. In this paper the potential use of luminosity tuning bumps is explored and compared to emittance tuning bumps.

 
 
RPPP011 Different Options for Dispersion Free Steering in the CLIC Main Linac linac, electron, positron, quadrupole 1251
 
  • D. Schulte
    CERN, Geneva
  Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).

Sophisticated beam-based alignment is essential in future linear colliders to preserve the beam emittance during the transport through the main linac. One such method is dispersion free steering. In this paper different options to implement this method are discussed, based on the use of different accelerating gradients, RF phases and bunch particle types during a beam pulse.

 
 
RPPP012 Collective Effects in the CLIC Damping Rings wiggler, damping, ion, radiation 1312
 
  • F. Zimmermann, M. Korostelev, D. Schulte
    CERN, Geneva
  • T.A. Agoh, K. Yokoya
    KEK, Ibaraki
  The small emittance, short bunch length, and high current in the CLIC damping ring could give rise to collective effects which degrade the quality of the extracted beam. In this paper, we survey a number of possible instabilities and estimate their impact on the ring performance. The effects considered include fast beam-ion instability, coherent synchrotron radiation, and electron cloud, in addition to conventional single and multi-bunch instabilities.  
 
RPPP020 Linear Damping Systems for the International Linear Collider damping, wiggler, positron, radiation 1689
 
  • G. Dugan
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: Supported by the National Science Foundation

The International Linear Collider requires very low transverse emittance beams in order to realize the specified high luminosity. These beams are conventionally produced using radiation damping in specially designed damping rings. A linear damping system, consisting of alternating wigglers and accelerating structures arranged in a straight line, can be considered to replace, or to augment, conventional damping rings. In this paper, the basic features, feasibility, advantages, and disadvantages, of such systems, as applied to the International Linear Collider, will be discussed.

 
 
RPPP021 Multivariate Optimization of ILC Parameters linac, luminosity, collider, 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.

 
 
RPPP024 Comparison of Beam-Based Alignment Algorithms for the ILC alignment, linac, quadrupole, shielding 1847
 
  • J.C. Smith, L. Gibbons, J.R. Patterson, D. L. Rubin
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • D. Sagan
    Cornell University, Department of Physics, Ithaca, New York
  • P. Tenenbaum
    SLAC, Menlo Park, California
  Funding: NSF and DOE.

The International Linear Collider (ILC) alignment tolerances require more sophisticated alignment techniques than those provided by survey alone. Various Beam-Based Alignment algorithms have been proposed to achieve the desired low emittance preservation. These algorithms are compared and their merits identified using the TAO accelerator simulation program.

 
 
RPPP025 CESR-c Wiggler Studies in the Context of the International Linear Collider Damping Rings wiggler, damping, dynamic-aperture, linear-collider 1880
 
  • J.T. Urban, G. Dugan
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: Work supported by the NSF.

We present a picture of the International Linear Collider (ILC) damping ring wiggler dynamics using the experience gained from the experimental and simulation-based research studying the wigglers used in the current configuration of the Cornell Electron Storage Ring (CESR). CESR is currently running at 1.8 GeV with 12 superconducting wigglers that have been designed, fabricated, tested, and simulated on-site. We will present results which include frequency map analyses and conventional dynamic aperture studies of CESR-c and the ILC damping rings. We will also provide results from an initial look at physical limitations in the design of the ILC damping ring wigglers.

 
 
RPPP026 Linear Accelerator Simulations with BMAD linac, simulation, lattice, longitudinal-dynamics 1937
 
  • J.T. Urban, L.J. Fields, D. Sagan
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: Work supported by the U.S. DOE.

BMAD is a subroutine library for simulating relativistic charged-particle dynamics. It has been used extensively as a diagnostic tool at the Cornell Electron Storage Ring (CESR). The BMAD libraries have recently been extended to include modeling of the dynamics of linear accelerators. Calculations of emittance dilution due to orbit offsets and misalignments have been compared with LIAR, Merlin and PLACET, and good agreement is found with both particle and macroparticle tracking through the NLC and Tesla lattices for the bunch compressor, main linac and final focus regions.

 
 
RPPP029 Analysis of Positron Collection in Linear Collider positron, target, electron, damping 2101
 
  • Y.K. Batygin
    SLAC, Menlo Park, California
  Funding: Work is supported by Department of Energy Contract No. DE-AC02-76SF00515

In the Linear Collider, the positron capture system includes a positron production target, a flux concentrator, and a linac to accelerate positrons up to the injection energy of the positron damping ring. Two schemes for positron production have been studied: (i) a conventional approach with an electron beam interacting with a high-Z target and (ii) polarized positron production using polarized photons generated in a helical undulator by electron beam which then interact with a positron production target. Efficiency of positron collector is defined by positron yield which is a ratio of positrons accepted into damping ring to the number of incident electrons or photons. The capture system has been optimized to insure high positron yield into the 6-dimensional acceptance of the damping ring keeping the high value of positron polarization. Various parameters affecting the positron capture are analyzed.

 
 
RPPP034 Multi-Stage Bunch Compressors for the International Linear Collider damping, linac, extraction, injection 2357
 
  • P. Tenenbaum, T.O. Raubenheimer
    SLAC, Menlo Park, California
  • A. Wolski
    LBNL, Berkeley, California
  We present bunch compressor designs for the International Linear Collider (ILC) which achieve a reduction in RMS bunch length from 6 mm to 0.3 mm via multiple stages of compression, with stages of acceleration inserted between the stages of compression. The key advantage of multi-stage compression is that the maximum RMS energy spread is reduced to approximately 1%, compared to over 3% for a single-stage design. Analytic and simulation studies of the multi-stage bunch compressors are presented, along with performance comparisons to a single-stage system. Parameters for extending the systems to a larger total compression factor are discussed.  
 
RPPP042 Emittance Dilution Due to Dipole Mode Rotation and Coupling in the Main Linacs of the ILC linac, simulation, coupling, dipole 2723
 
  • R.M. Jones, R.H. Miller
    SLAC, Menlo Park, California
  Funding: This work is supported by Department of Energy grant number DE-AC02-76SF00515.

The progress of multiple bunches of charged particles down the main L-band linacs of the ILC (International Linear Collider) can be disrupted by wakefields. These wakefields correspond to the electromagnetic fields excited in the accelerating cavities and have both long-range and short-range components. Here we investigate the impact of the long-range wakefields on the trailing bunches caused by the leading bunches. In general, the dipole mode degeneracy will be removed both because of manufacturing errors and because the higher order mode couplers are dipole asymmetric and lie neither in the horizontal nor vertical plane. This creates 2 dipole eigenmodes which are rotated with respect to the horizontal and vertical axes and which may have slightly different frequencies. These eigenmodes can couple the horizontal and vertical dipole excitations. We simulate the progress of the ILC beam down the collider under the influence of these wakefields. In particular, we investigate the consequences on the final emittance dilution of the beam of coupling of the horizontal to the vertical motion of the beam.

 
 
RPPP043 Emittance Dilution Due to Many-Band Long-Range Dipole Wakefields in the International Linear Collider Main Linacs linac, dipole, simulation, linear-collider 2792
 
  • R.M. Jones
    SLAC, Menlo Park, California
  • N. Baboi
    DESY, Hamburg
  Funding: This work is supported by Department of Energy grant number DE-AC02-76SF00515.

We investigate the emittance dilution that occurs due to long range wakefields in the ILC L-band linacs. The largest kick factors (proportional to the transverse fields which transversely kick the beam off axis) from the first six bands are included in our simulations. These higher order dipole modes are damped by carefully orientating higher order mode couplers at both ends of each cavity. We investigate the dilution in the emittance of a beam with a random misalignment of cavities down the complete linac. In particular, the impact of a poorly damped dipole mode, on the overall emittance dilution down the complete linac is focused upon. The transverse alignment tolerances imposed on the cavities due to these wakefields are also discussed.

 
 
RPPP046 An L-Band Polarized Electron PWT Photoinjector for the International Linear Collider (ILC) electron, cathode, vacuum, simulation 2902
 
  • D. Yu, A. Baxter, P. Chen, M. Lundquist, Y. Luo, A. S. Smirnov
    DULY Research Inc., Rancho Palos Verdes, California
  Funding: Work supported by DOE SBIR Grant No. DE-FG02-03ER83846.

A multi-cell, standing-wave, L-band, p-mode, plane-wave-transformer (PWT) photoinjector with an integrated photocathode in a novel linac structure is proposed by DULY Research Inc. as a polarized electron source. The PWT photoinjector is capable of operation in ultra high vacuum and moderate field gradient. Expected performance of an L-band polarized electron PWT injector operating under the parameters for the International Linear Collider is presented. The projected normalized transverse rms emittance is an order of magnitude lower than that produced with a polarized electron dc gun followed by subharmonic bunchers.

 
 
RPPP051 Characterization of a 6-km Damping Ring for the International Linear Collider lattice, dynamic-aperture, damping, wiggler 3147
 
  • A. Xiao
    Fermilab, Batavia, Illinois
  • L. Emery
    ANL, Argonne, Illinois
  Several damping ring designs for the International Linear Collider have been proposed recently. One particular design has a circumference of 6 km (hoping to take advantage of future kicker technology advances), TME arc cells, and 77 m of 2 T wigglers. Several beam dynamics characterizations and optimizations are reported. We used the accelerator code elegant for matching and tracking, and a 100-CPU linux cluster to provide high throughput.  
 
RPPP054 Achieving Large Dynamic Aperture in the ILC Damping Rings lattice, damping, dynamic-aperture, sextupole 3277
 
  • A. Wolski
    LBNL, Berkeley, California
  • Y. Cai
    SLAC, Menlo Park, California
  Funding: Work supported by US Department of Energy, Director, Office of Science - Contract Nos. DE-AC03-76SF00098 and DE-AC03-76SF00515.

The Damping Rings for the International Linear Collider have challenging requirements for the acceptance, because of the high average injected beam power and the large beam produced from the positron source. At the same time, the luminosity goals of the collider mean that the natural emittance must be very small, and this makes it particularly difficult to achieve a good dynamic aperture. We describe a design approach and present a lattice design that meets the emittance specification and has a very promising dynamic aperture. We also discuss the potential impact of the damping wiggler and of magnet errors.

 
 
RPPT006 Commissioning of TTF2 Bunch Compressor for the Femtosecond (FS) FEL Mode Operation linac, simulation, gun, single-bunch 991
 
  • Y. Kim, Y. Kim, D. Son
    CHEP, Daegu
  Funding: For the TESLA Test Facility FEL team.

To get lasing at TTF2, we should supply high quality electron beams with a high peak current, a low slice emittance, and a low slice energy spread. To supply a high peak current, we compress bunch length with two bunch compressors. During TTF2 lasing period, there was no available special bunch length diagnostic tool such as LOLA cavity or streak camera. However we could optimize TTF2 bunch compressors by monitoring pyro-electric detector signal, by measuring emittance, and by monitoring beam images at chicane center and dump region, and by comparing operational machine conditions with simulation results. In this paper, we describe our various commissioning experiences of TTF2 bunch compressor to generate a femtosecond-long spike with a high peak current.

 
 
RPPT011 Optimized Bunch Compression System for the European XFEL space-charge, optics, linac, RF-structure 1236
 
  • T. Limberg, V. Balandin, R. Brinkmann, W. Decking, M. Dohlus, K. Floettmann, N. Golubeva, Y. Kim, E. Schneidmiller
    DESY, Hamburg
  The European XFEL bunch compressor system has been optimized for greater flexibility in parameter space. Operation beyond the XFEL design parameters is discussed in two directions: achieving the uppermost number of photons in a single pulse on one hand and reaching the necessary peak current for lasing with a pulse as short as possible on the other. Results of start-to-end calculations including 3D-CSR effects, space charge forces and the impact on wake fields demonstrate the potential of the XFEL for further improvement or, respectively, its safety margin for operation at design values.  
 
RPPT012 Layout of the Diagnostic Section for the European XFEL lattice, diagnostics, electron, radiation 1285
 
  • C. Gerth, Mr. Roehrs, H. Schlarb
    DESY, Hamburg
  Fourth generation synchrotron light sources, such as the European Free Electron Laser (XFEL) project, are based on an exponential gain of the radiation amplification in a single pass through a long undulator magnet. To initiate the FEL process and to reach staturation, precise monitoring and control of the electron beam parameters is mandatory. Most challenging are the longitudinal compression processes in magnetic chicanes of the high brightness electron bunch emitted from an RF photo-injector. To measure and control the beam properties after compression, careful consideration must be given to the design of a diagnostic section and the choice of beam monitors. In this paper, the proposed layout of the XFEL diagnostics beamline is discussed and emphasis is put on the possibility of monitoring on-line the slice energy spread, slice emittance and longitudinal bunch profile with high accuracy.  
 
RPPT013 Status of the SPARC Project laser, gun, undulator, klystron 1327
 
  • L. Serafini, F. Alessandria, A. Bacci, S. Cialdi, C. De Martinis, D. Giove, M. Mauri, M. Rome, L. Serafini
    INFN-Milano, Milano
  • D. Alesini, M. Bellaveglia, S. Bertolucci, M.E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, L. Ficcadenti, D. Filippetto, V. Fusco, A. Gallo, G. Gatti, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, M.  Migliorati, A. Mostacci, L. Palumbo, L. Pellegrino, M.A. Preger, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario
    INFN/LNF, Frascati (Roma)
  • I. Boscolo, C. Maroli, V. Petrillo
    Universita' degli Studi di Milano, MILANO
  • F. Broggi
    INFN/LASA, Segrate (MI)
  • L. Catani, E. Chiadroni, A. Cianchi, E. Gabrielli, S. Tazzari
    INFN-Roma II, Roma
  • F. Ciocci, G. Dattoli, A. Dipace, A. Doria, F. Flora, G.P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, P.L. Ottaviani, S. Pagnutti, G. Parisi, L. Picardi, M. Quattromini, A. Renieri, G. Ronci, C. Ronsivalle, M. Rosetti, E. Sabia, M. Sassi, A. Torre, A. Zucchini
    ENEA C.R. Frascati, Frascati (Roma)
  • D. Dowell, P. Emma, C. Limborg-Deprey, D.T. Palmer
    SLAC, Menlo Park, California
  • D. Levi, M. Mattioli, G. Medici, P. Musumeci, D. Pelliccia
    Università di Roma I La Sapienza, Roma
  • M. Nisoli, S. Stagira, S. de Silvestri
    Politecnico/Milano, Milano
  • M. Petrarca
    INFN-Roma, Roma
  • J.B. Rosenzweig
    UCLA, Los Angeles, California
  The SPARC project has entered its installation phase at INFN-LNF: its main goal is the promotion of an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments. The design of the 150 MeV photoinjector has been completed and the construction of its main components is in progress, as well as the design of the 12 m undulator. In this paper we will report on the installation and test of some major components, like the Ti:Sa laser system to drive the photo-cathode, the RF gun, the RF power system, as well as some test results on the RF deflector and 4th harmonic X-band cavity prototypes. Advancements in the control and beam diagnostics systems will also be reported, in particular on the emittance-meter device for beam emittance measurements in the drift space downstream the RF gun. Recent results on laser pulse shaping, obtained with two alternative techniques (DAZZLER and Liquid Crystal Mask), show the feasibility of producing 10 ps flat-top laser pulses in the UV with rise time below 1 ps, as needed to maximize the achievable beam brightness. First FEL experiments have been proposed, using SASE, seeding and non-linear resonant harmonics: these will be briefly described.  
 
RPPT015 Start To End Simulation for the SPARX Project linac, brightness, simulation, undulator 1455
 
  • C. Vaccarezza, R. Boni, M. Boscolo, M. Ferrario, V. Fusco, M.  Migliorati, L. Palumbo, B. Spataro, M. Vescovi
    INFN/LNF, Frascati (Roma)
  • L. Giannessi, M. Quattromini, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • L. Serafini
    INFN-Milano, Milano
  The first phase of the SPARX project now funded by Government Agencies, is an R&D activity focused on developing techniques and critical components for future X-ray facilities. The aim is the generation of electron beams with the ultra-high peak brightness required to drive FEL experiments. The FEL source realization will develop along two lines: (a) the use of the SPARC high brightness photoinjector to test RF compression techniques and the emittance degradation in magnetic compressors due to CSR, (b) the production of radiation in the range of 3-5 nm, both in SASE and SEEDED FEL configurations, in the so called SPARXINO test facility, upgrading the existing Frascati 800 MeV LINAC. In this paper we present and discuss the preliminary start to end simulations results.  
 
RPPT017 Wake Field Effect on the SASE Performance of PAL XFEL undulator, radiation, linac, electron 1549
 
  • J.-S. Oh, I.S. Ko, T.-Y. Lee, W. Namkung
    PAL, Pohang, Kyungbuk
  Funding: Supported by the POSCO and the MOST, Korea.

The PAL XFEL will supply coherent radiations from VUV to X-rays. X-ray FEL for 0.3 nm lasing requires a 3-GeV driver linac and a 60-m long in-vacuum undulator with a narrow variable gap. The linac should supply highly bright beams with emittance of 1.2 mm-mrad, a peak current of 3.5 kA, and a low energy spread of 0.03%. The beam quality is degraded along the undulator trajectory due to the energy loss, the wake field, and the magnetic field errors, etc. Especially the wake field effect is most sensitive parameter due to the narrow gap of the undulator. The preliminary design details of undulators for PAL-XFEL are presented with parametric analysis. The temporal SASE performance is analyzed using simulation tools such as GENESIS and SIMPLEX.

 
 
RPPT020 Space Charge Effects for the ERL Prototype Injector Line at Daresbury Laboratory space-charge, dipole, linac, quadrupole 1676
 
  • B.D. Muratori, H.L. Owen
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • C. Gerth
    DESY, Hamburg
  • M.J. de Loos, S.B. van der Geer
    PP, Soest
  Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will operate at a beam energy of 35 MeV. In this paper we examine the space charge effects on the beam dynamics in the ERLP injector line. A Gaussian particle distribution is tracked with GPT (General Particle Tracer) through the injection line to the main linac to calculate the effect of 3Dspace charge in the dipoles. The nominal beam energy in the injection line is 8.3 MeV and the bunch charge 80 pC. The effects of space charge on the transverse and longitudinal emittance are studied for various electron beam parameter settings.  
 
RPPT021 Inducing Strong Density Modulation with Small Energy Dispersion in Particle Beams and the Harmonic Amplifier Free Electron Laser electron, radiation, bunching, undulator 1718
 
  • B.W.J. McNeil, G.R.M. Robb
    Strathclyde University, Glasgow
  • M.W. Poole
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Funding: We acknowledge the support of the European Union's EUROFEL Design Study, CCLRC, and the Scottish Universities Physics Alliance.

We present a possible method of inducing a periodic density modulation in a particle beam with little increase in the energy dispersion of the particles. The flow of particles in phase space does not obey Liouville's Theorem. The method relies upon the Kuramoto-like model of collective synchronism found in free electron generators of radiation, such as Cyclotron Resonance Masers and the Free Electron Laser. For the case of an FEL interaction, electrons initially begin to bunch and emit radiation energy with a correlated energy dispersion which is periodic with the FEL ponderomotive potential. The relative phase between potential and particles is then changed by approximately 180 degrees. The particles continue to bunch, however, there is now a correlated re-absorption of energy from the field. We show that, by repeating this relative phase change many times, a significant density modulation of the particles may be achieved with only relatively small energy dispersion. A similar method of repeated relative electron/radiation phase changes is used to demonstrate supression of the fundamental growth in a high gain FEL so that the FEL lases at the harmonic only.

 
 
RPPT022 Optics for High Brightness and High Current ERL Project at BNL gun, electron, dipole, linac 1775
 
  • D. Kayran, I. Ben-Zvi, R. Calaga, X.Y. Chang, J. Kewisch, V. Litvinenko
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy and partially funded by the US Department of Defence

An energy recovery linac (ERL), under development at Brookhaven National Laboratory [1,2], will push ERLs further towards high current and high brightness beams. This R&D ERL will operate in two modes: a high current mode and a high charge mode. In this paper we present a lattice of the machine and PARMELA simulations from the cathode to the beam dump. We discuss the design considerations and present main parameters for various modes of operation.

 
 
RPPT026 Status of a Plan for an ERL Extension to CESR linac, undulator, electron, optics 1928
 
  • G. Hoffstaetter, S.A. Belomestnykh, J.S.-H. Choi, Z. Greenwald, M. Liepe, H. Padamsee, D. Sagan, C. Song, R.M. Talman, M. Tigner
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • I.V. Bazarov, K.W. Smolenski
    Cornell University, Ithaca, New York
  • D.H. Bilderback, M.G. Billing, S.M. Gruner, Y. Li, C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  Funding: Cornell University.

We describe the status of plans to build an Energy-Recovery Linac (ERL) X-ray facility at Cornell University. This 5 GeV ERL is an upgrade of the CESR ring that currently powers the Cornell High Energy Synchrotron Source (CHESS). Due to its very small electron-beam emittances, it would dramatically improve the capabilities of the light source and result in X-ray beams orders of magnitude better than any existing storage ring light source. The emittances are based upon simulations for currents that are competitive with ring-based sources. The ERL design that is presented has to allow for non-destructive transport of these small emittances. The design includes a series of X-ray beamlines for specific areas of research. As an upgrade of the existing storage ring, special attention is given to reuse of many of the existing ring components. Options of bunch compression are discussed, tolerances for emittance growth are specified, and simulations of the beam-breakup instability and methods of increasing its threshold current are shown. This planned upgrade illustrates how other existing storage rings could be upgraded as ERL light sources with vastly improved beam qualities.

 
 
RPPT027 Considerations on Beam Quality Control in MIT X-Ray FEL linac, electron, laser, feedback 1961
 
  • D. Wang, W. Graves, D. Wang, T. Zwart
    MIT, Middleton, Massachusetts
  • P. Emma, J. Wu
    SLAC, Menlo Park, California
  • G. Huang
    LBNL, Berkeley, California
  Funding: U.S. Department of Energy.

The next generation of x-ray FEL requires very high quality electron beams for producing unprecedented x-ray radiations. In proposed x-ray FEL facilities, especially those that use multi-stage high gain high harmonic (HGHG) principle to obtain coherence in both transverse and longitudinal dimensions, the arrival timing of electron bunches must be very precise to ensure the seed laser overlap the desired sections of the electron bunch. A scheme is proposed to achieve 10s fs level of arrival timing control level.

 
 
RPPT029 Diagnostics for the LCLS Photoinjector Beamline gun, cathode, injection, diagnostics 2089
 
  • C. Limborg-Deprey, D. Dowell, J.F. Schmerge
    SLAC, Menlo Park, California
  Funding: This work was supported by U.S. Department of Energy, contract No. DE-AC03-76SF00515A06.

Two spectrometers have been added to the LCLS photoinjector beamline. The first one will be located close to the exit of the Photoinjector RF gun. With this diagnostic, we will measure beam energy, energy spread (correlated and uncorrelated), possibly deleterious structure in the longitudinal phase space induced by longitudinal space charge force, and slice thermal emittance This extensive characterization of the 5MeV electron bunch will be made possible by combining this spectrometer with other diagnostics (YAG screens and Cerenkov Radiator). A second spectrometer located at the end of the beamline has been designed to characterize the 6 dimensional phase space of the 135MeV beam to be injected in the main accelerator. At that second spectrometer station, we will measure energy, energy spread (correlated and uncorrelated), longitudinal phase space, slice emittances … Those last two measurements require using this spectrometer in combination with the transverse RF deflecting cavity and with the quadrupole scan emittance station. The designs of these two spectrometers have been supported by simulations from MAD and PARMELA.

 
 
RPPT030 Alternate Tunings for the Linac Coherent Light Source Photoinjector laser, cathode, space-charge, injection 2140
 
  • C. Limborg-Deprey, P. Emma
    SLAC, Menlo Park, California
  Funding: This work was supported by US Department of Energy, contract No. DE-AC03-76SF00515A06.

The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. The LCLS Photoinjector beamline has been designed to deliver 10 ps long electron bunches of 1nC with a normalized transverse emittance of less than 1 mm.mrad for 80% of the slices constituting the core of the bunch at 135 MeV. Tolerances and regulation requirements are tight for this tuning. The main contribution to emittance is the "cathode emittance which counts for 0.72 mm.mrad for the nominal tuning. As the "cathode emittance" scales linearly with laser spot radius, the emittance will be dramatically reduced for smaller radius, but this is only possible at lower charge. In particular, for a 0.2nC, we believe we can achieve an emittance closer to 0.4 mm.mrad. This working point will be easier to tune and the beam quality should be much easier to maintain than for the nominal one. In this paper, we also discuss how emittance could be further reduced by using the appropriate laser pulse shaping.

 
 
RPPT032 High Current Energy Recovery Linac at BNL linac, electron, lattice, gun 2242
 
  • V. Litvinenko, D.B. Beavis, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, A. Burrill, R. Calaga, P. Cameron, X.Y. Chang, R. Connolly, D.M. Gassner, H. Hahn, A. Hershcovitch, H.-C. Hseuh, P.D.J. Johnson, D. Kayran, J. Kewisch, R.F. Lambiase, G.J. Mahler, G.T. McIntyre, W. Meng, T.C.N. Nehring, T. Nicoletti, B. Oerter, D. Pate, J. Rank, T. Rao, T. Roser, T. Russo, J. Scaduto, K. Smith, N.W.W. Williams, K.-C. Wu, V. Yakimenko, K. Yip, A. Zaltsman, Y. Zhao
    BNL, Upton, Long Island, New York
  • H. Bluem, A. Burger, M.D. Cole, A.J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A.M.M. Todd
    AES, Princeton, New Jersey
  • J.R. Delayen, L. W. Funk, H.L. Phillips, J.P. Preble
    Jefferson Lab, Newport News, Virginia
  Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the U.S. Department of Energy.

We present the design and the parameters of a small Energy Recovery Linac (ERL) facility, which is under construction at BNL. This R&D facility has goals to demonstrate CW operation of ERL with average beam current in the range of 0.1 - 1 ampere, combined with very high efficiency of energy recovery. The possibility for future up-grade to a two-pass ERL is being considered. The heart of the facility is a 5-cell 703.75 MHz super-conducting RF linac with HOM damping. Flexible lattice of ERL provides a test-bed for testing issues of transverse and longitudinal instabilities and diagnostics of intense CW e-beam. We present the status and plans for this facility.

 
 
RPPT040 Weak FEL Gain Detection with a Modulated Laser-Based Beam Heater undulator, laser, radiation, electron 2636
 
  • P. Emma, Z. Huang, J. Wu
    SLAC, Menlo Park, California
  For an x-ray free-electron laser (FEL) such as the LCLS, the FEL gain signal is accompanied by spontaneous radiation with a significant power level. Detecting the weak FEL gain among the large spontaneous background in the early stage of the exponential growth or for a low quality electron beam is important in commissioning the FEL. In this paper, we describe a simple "lock-in" method of weak FEL gain detection by slowly modulating the laser power of a designated beam heater that controls the local energy spread of the electron beam. We present numerical modeling that shows the effectiveness of this method and discuss its implementation in the LCLS.  
 
RPPT053 Studies of the Injection System in the Decay Ring of Beta-Beam Neutrino Souce Project injection, septum, ion, factory 3221
 
  • J. Payet, A. Chance
    CEA/CEN, Gif-sur-Yvette
  After being accelerated the beta radioactive ions are accumulated in a decay ring. The losses due to their decay are compensated with regular injections in presence of filled bucket. Without a damping mechanism, the new particles are injected at a different energy from the stored beam energy, then the old and the new buckets are merged with RF manipulation. This type of injection has to be done, in a dispersive region, in presence of closed orbit bump and a septum magnet. The sizes of the injected beam and of the stored beam have to be adjusted in order to minimize the losses on the septum and to maximize the stored intensity keeping small beam sizes. The dispersion has to be large enough in order to decrease the energy difference. The injection system may be located either in the arc or in a straight section, both possibilities have been studied.  
 
RPPT061 Linear Quadrupole Cooling Channel for a Neutrino Factory quadrupole, simulation, factory, acceleration 3526
 
  • C. Johnstone
    Fermilab, Batavia, Illinois
  • M. Berz, K. Makino
    MSU, East Lansing, Michigan
  Funding: Work supported by the U.S. Dept. of Energy under contract no. DE-AC02-76CH03000.

The staging and optimization in the design of a Neutrino Factory are critically dependent on the choice and format of accelerator. Possibly the simplest, lowest-cost scenario is a nonscaling FFAG machine coupled to a linear (no bending) transverse cooling channel constructed from the simplest quadrupole lens system, a FODO cell. In such a scenario, transverse cooling demands are reduced by a factor of 4 and no longitudinal cooling is required relative to acceleration using a Recirculating Linac (RLA). Detailed simulations further show that a quadrupole-based channel cools efficiently and over a momentum range which is well-matched to FFAG acceleration. Details and cooling performance for a quadrupole channel are summarized in this work.

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

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

 
 
ROPA006 Terascale Beam-Beam Simulations for Tevatron, RHIC and LHC simulation, antiproton, proton, injection 535
 
  • J. Qiang
    LBNL, Berkeley, California
  Funding: This work was supported by a SciDAC project in accelerator physics which is supported by the US DOE/SC Office of High Energy Physics and the Office of Advanced Scientific Computing Research.

In this paper, we report on recent advances in terascale simulations of the beam-beam effects in Tevatron, RHIC and LHC. Computational methods for self-consistent calculation of the beam-beam forces are reviewed. Applications to the studies of the multiple bunch beam-beam interactions in the Tevatron and the RHIC will be presented. The study of emittance growth due to the beam-beam interactions in the LHC will also be presented.

 
 
ROPC001 SNS Warm Linac Commissioning Results linac, rfq, SNS, quadrupole 97
 
  • A.V. Aleksandrov
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The Spallation Neutron Source accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H- injector, capable of producing one-ms-long pulses at 60Hz repetition rate with 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The 2.5MeV beam from the Front End is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in the Superconducting Linac. The staged beam commissioning of the accelerator complex is proceeding as component installation progresses. The Front End, Drift Tube Linac and three of the four Coupled-Cavity Linac modules have been commissioned with beam at ORNL. Results and status of the beam commissioning program will be presented.

 
 
ROPC005 RIA Post Accelerator Design ion, linac, rfq, acceleration 425
 
  • S.O. Schriber
    NSCL, East Lansing, Michigan
  Overall design of the post accelerator for the RIA project is described with emphasis on performance for different ion beams. Characteristics for beams from A=10 to A=240 will be provided with an estimate of output intensities. The rational for selection of different accelerating structures, both for the normal conducting and for the superconducting types, will be provided for a system design that accelerates beams to at least 10 MeV/u.  
 
ROPC008 Experimental Progress in Fast Cooling in the ESR ion, electron, injection, scattering 615
 
  • M. Steck, K. Beckert, P. Beller, B.  Franzke, F. Nolden
    GSI, Darmstadt
  The ESR storage ring at GSI is operated with highly charged heavy ions. Due to the high electric charge the ions interact much stronger with electromagnetic fields. Therefore both cooling methods which are applied to stored ions in the ESR, stochastic cooling and electron cooling, are more powerful than for singly charged particles. The experimental results exhibit cooling times for stochastic cooling of a few seconds. For cold ion beams, electron cooling provides cooling times which are one to two orders of magnitude smaller. The beams are cooled to beam parameters which are limited by intrabeam scattering. At small ion numbers, however, intrabeam scattering is suppressed by electron cooling, clear evidence was found that the ion beam forms a one-dimensional ordered structure, a linear chain of ions. The strengths of stochastic cooling and electron cooling are complementary and can be combined favorably. Stochastic cooling is employed for pre-cooling of hot secondary beams followed by electron cooling to provide ultimate beam quality. In a similar manner, first experiments with carbon ions have been performed to use electron cooling as a pre-cooling method in combination with laser cooling.  
 
ROPC010 Testing, Installation, Commissioning and First Operation of the ISIS RFQ Pre-Injector Upgrade rfq, linac, vacuum, quadrupole 695
 
  • A.P. Letchford, D.C. Faircloth, D.J.S. Findlay, M. Perkins, A.F. Stevens, M. Whitehead
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  Situated at the Rutherford Appleton Laboratory (Oxon., UK), ISIS is currently the world's most intense pulse spallation neutron source, delivering 160 kW of 800 MeV protons to a tungsten target at 50 Hz. A major facility upgrade programme involves the construction of a second, 10 Hz target and an increase in the total beam power of up to 50% (i.e. up to 240 kW). To achieve the planned increase in average beam current to 300 μA whilst maintaining the current manageable levels of beam loss, four 2nd harmonic RF cavities have been installed in the synchrotron and the ageing Cockroft-Walton pre-injector in the linac has been replaced with a 665 keV, 202.5 MHz, 4-rod RFQ. This paper describes the extensive testing, installation, commissioning and successful initial operation of the RFQ pre-injector upgrade.  
 
FPAE004 Optical Matching of Slowly Extracted Beam with Transport System at HIMAC simulation, extraction, optics, heavy-ion 910
 
  • T. Furukawa, K. Noda, E. Takada, M. Torikoshi, T.H. Uesugi, S. Yamada
    NIRS, Chiba-shi
  • T. Fujimoto, M. Katsumata, S. Shibuya, T. Shiraishi
    AEC, Chiba
  The optical matching between the ring and the transport line plays important role in order to control the beam size and profile after the transport. At HIMAC, thus, we have studied the optical matching of the slowly extracted beam. As a result, it was verified that the beam size of the slowly extracted beam were controlled owing to the optical matching. It was also found that small deviation of quadrupole strength in the ring brings orbit distortion at the transport system.  
 
FPAE008 Iso-Adiabatic Merging of pbar Stacks in the Recycler simulation, antiproton, collider, 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 synchrotron, collider, bunching, scattering 1153
 
  • D.V. Neuffer, D.R. Broemmelsiek, A.V. Burov, S. Nagaitsev
    Fermilab, Batavia, Illinois
  Stochastic cooling with bunched beam in a linear bucket has been obtained and implemented operationally in the fermilab recycler. In this implementation the particle bunch length is much greater than the cooling system wavelengths. The simultaneous longitudinal bunching enables cooling to much smaller longitudinal emittances than the coasting beam or barrier bucket system. Characteristics and limitations of bunched beam stochastic cooling are discussed.  
 
FPAE010 Barrier RF System and Applications in Main Injector booster, proton, injection, radiation 1189
 
  • W. Chou, D. Wildman
    Fermilab, Batavia, Illinois
  • A. Takagi
    KEK, Ibaraki
  • H. Zheng
    CALTECH, Pasadena, California
  Funding: Work supported by the Universities Research Association, INC. under contract with the U.S. Department of Energy NO. DE-AC02-76CH03000 and by the US-Japan Collaboration in High Energy Physics.

A wideband RF system (the barrier RF) has been built and installed in the Fermilab Main Injector. The cavities are made of low Q Finemet cores. The modulators use high voltage fast solid-state switches. It can generate ±7 kV single square voltage pulses. It is used to stack two proton batches to double the bunch intensity for pbar production. The stacked high intensity beams have been successfully accelerated to 120 GeV with small losses. A new test to continuously stack 12 batches for the NuMI experiment is under way.

 
 
FPAE012 Experimental Test of a New Antiproton Acceleration Scheme in the Fermilab Main Injector acceleration, antiproton, injection, collider 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.

 
 
FPAE017 Observation of Longitudinal Diffusion and Cooling Due to Intrabeam Scattering at the Fermilab Recycler Ring antiproton, scattering, proton, luminosity 1560
 
  • M. Hu, S. Nagaitsev
    Fermilab, Batavia, Illinois
  The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with both stochastic and electron cooling systems. In this note the technique for diffusion rate measurement, beam parameters and the analysis of data are presented, as well as the effect of intrabeam scattering on the operational considerations for the storage and cooling of the antiproton beam in the Recycler.  
 
FPAE025 Study of Slow Beam Extraction Through the Third Order Resonance with Transverse Phase Space Manipulation by a Mono-Frequency RFKO betatron, electron, sextupole, extraction 1892
 
  • A. Miyamoto, H. Hama, F. Hinode, M. Kawai, K. Shinto, T. Tanaka
    LNS, Sendai
  An electron pulse-stretcher ring (STB ring) has a function which converts a pulse beam generated by RF linac into a quasi-continuous beam. Circulating beam in the ring is extracted by the third order resonance. Since there is no accelerating field in the ring, the beam approaches a transverse resonance condition due to synchrotron radiation loss with finite chromaticity. The extracted beam from the ring has some spread in time and space corresponding to injected beam from linac even if the injected beam is perfectly matched to the ring optics. However, the extracted beam emittance can be reduced by applying a phase space manipulation using an RF shaker. Under the influence of perturbation using an RF shaker driven by a mono-frequency, the betatron amplitude of circulating beam can be controlled in order to reduce the extracted beam emittance. The experimental results will be reported in this conference.  
 
FPAE029 Setup and Performance of the RHIC Injector Accelerators for the 2005 Run with Copper Ions booster, injection, ion, extraction 2068
 
  • C.J. Gardner, L. Ahrens, J.G. Alessi, J. Benjamin, M. Blaskiewicz, J.M. Brennan, K.A. Brown, C. Carlson, J. DeLong, J. Glenn, T. Hayes, W.W. MacKay, G.J. Marr, J. Morris, T. Roser, F. Severino, K. Smith, D. Steski, N. Tsoupas, A. Zaltsman, K. Zeno
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

Copper ions for the 2005 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators will be reviewed.

 
 
FPAE042 Beam Commissioning of the Superconducting RFQs of the New LNL Injector PIAVE rfq, ion, linac, simulation 2696
 
  • A. Pisent, G. Bisoffi, D. Carlucci, M. Cavenago, F. Chiurlotto, M. Comunian, E. Fagotti, A. Galatà, M. Poggi, A.M. Porcellato, M. Sattin
    INFN/LNL, Legnaro, Padova
  • T. Kulevoy
    ITEP, Moscow
  PIAVE is the new injector of the LNL superconducting heavy ion linac ALPI; the injector is able to accelerate ions up to U (Q/q=8.5) with a final energy of more than 1 MeV/u. During the last two months of 2004 the superconducting RFQ, composed by two Nb structures operating at 80 MHz, has been commissioned using the O+3 and Xe+18 beams produced by the ECRIS ALICE. The beam has been accelerated up to 587 keV/u reaching the main design parameters (energy, longitudinal and transverse emittance, transmission) and demonstrating a stable and reproducible operation. This is the first operational beam accelerated by a superconducting RFQ.  
 
FPAE043 Transverse Tuning Scheme for J-PARC Linac linac, quadrupole, monitoring, coupling 2750
 
  • M. Ikegami, Z. Igarashi, S. Lee
    KEK, Ibaraki
  • H. Akikawa, K. Hasegawa, Y. Kondo, T. Ohkawa
    JAERI, Ibaraki-ken
  • H. Ao, S. Sato, T. Tomisawa, A. Ueno
    JAERI/LINAC, Ibaraki-ken
  In a high-intensity linac, precise transverse matching is essential for beam halo mitigation. In this paper, we present the supposed transverse tuning scheme for J-PARC linac and the planned beam diagnostic layout for it. Relevantly, we briefly touch upon the tuning scenario for the arc section and the transverse halo collimator system which are located between the linac and the succeeding ring.  
 
FPAE054 Front End Design of a Multi-GeV H-minus Linac focusing, rfq, linac, lattice 3286
 
  • P.N. Ostroumov, K.W. Shepard
    ANL, Argonne, Illinois
  • G.W. Foster, I.G. Gonin, G. Romanov
    Fermilab, Batavia, Illinois
  Funding: This work was supported by the U.S. Department of Energy under Contracts No. W-31-109-ENG-38 and DE-AC02-76CH03000.

The proposed 8-GeV driver at FNAL is based on ~480 independently phased SC resonators. Significant cost saving is expected by using an rf power fan out from high-power klystrons to multiple cavities. Successful development of superconducting (SC) multi-spoke resonators operating at ~345-350 MHz provides a strong basis for their application in the front end of multi-GeV linear accelerators. Such a front-end operating at 325 MHz would enable direct transition to high-gradient 1300 MHz SC TESLA-style cavities at ~400 MeV. The proposed front end consists of 5 sections: a conventional RFQ, room-temperature (RT) cross-bar H-type (CH) cavities, single-, double- and triple-spoke superconducting resonators. For several reasons which are discussed in this paper there is a large advantage in using independently phased RT CH-cavities between the RFQ and SC sections in the energy range 3-15 MeV.

 
 
FPAE055 Heavy-Ion Beam Dynamics in the RIA Post-Accelerator linac, rfq, focusing, ion 3301
 
  • P.N. Ostroumov, V.N. Aseev
    ANL, Argonne, Illinois
  • A. Kolomiets
    ITEP, Moscow
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38.

The RIB linac includes two strippers for the heaviest ions and three main sections: a room temperature injector up to an energy of ~100 keV/u, a superconducting (SC) linac for ions with charge-to-mass ratio 1/66 or more up to an energy of ~1 MeV and a higher energy SC linac to produce 10 MeV/u beams up to the mass of uranium. The RIA post-accelerator is a complex system designed for acceleration singly-charged ions before the stripper and includes many different accelerating and focusing structures operating both at room and cryogenic temperatures. Extensive accelerator design studies and end-to-end beam dynamics simulations have been performed to minimize the cost of the linac while providing high-quality and high-intensity radioactive beams. Specifically, we have found that cost-effective acceleration can be provided by several hybrid RFQs in the front end. The hybrid RFQs have been proposed and developed for acceleration of low-velocity heavy ions.* For the beam focusing in the second section it is appropriate to use electrostatic lenses and SC quadrupoles inside common cryostats with the resonators. The electrostatic lenses are most effective in the first cryostat of the SC linac.

*P.N. Ostroumov and A.A. Kolomiets. Proc. of the PAC-2001, Chicago, IL, June 18-22, 2001, p. 4077.

 
 
FPAE057 Beam Dynamics Studies and Beam Quality in the SNS Normal-Conducting Linac linac, ion-source, ion, simulation 3381
 
  • S. Henderson, A.V. Aleksandrov, D.A. Bartkoski, C. Chu, S.M. Cousineau, V.V. Danilov, G.W. Dodson, J. Galambos, D.-O. Jeon, M.A. Plum, M.P. Stockli
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos and Oak Ridge.

The Spallation Neutron Source accelerator systems will provide a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron production. The accelerator complex consists of an H- injector capable of producing 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The linear accelerator consists of a Drift Tube Linac, a Coupled-Cavity Linac and a Superconducting Linac which provide 1.5 mA average current to the accumulator ring. The staged beam commissioning of the accelerator complex is proceeding as component installation progresses. Recently, the normal-conducting linear accelerator was beam commissioned. A number of beam dynamics and beam quality measurements will be reported, including the measurement of transverse emittances in the H- injector, and the evolution of halo and emittance along the linac.

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

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

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

 
 
FPAE062 Beam Parameters of a Two-Sectional Electron Linac with the Injector Based on a Resonance System with Evanescent Oscillations linac, simulation, electron, resonance 3567
 
  • V.V. Mytrochenko, M.I. Ayzatskiy, V.N. Boriskin, A. Dovbnya, I.V. Khodak, V.A. Kushnir, A. Opanasenko, S.A. Perezhogin, A.N. Savchenko, D.L. Stepin, V.I. Tatanov, Z.V. Zhiglo
    NSC/KIPT, Kharkov
  The S-band electron linac has been designed at NSC KIPT to cover an energy range from 30 to about of 100 MeV. The linac consists of a couple of the four-meter long piecewise homogeneous accelerating sections. Each section is supplied with RF power from a separate klystron. The peculiarity of the linac is using of the injector based on evanescent oscillations. The report presents both simulation results of self-consistent particle dynamics in the linac and results of measurement of beam parameters.  
 
FPAE067 Present Design and Calculation for the Injection-Dump Line of the RCS at J-PARC injection, beam-losses, quadrupole, linac 3739
 
  • P.K. Saha, N. Hayashi, H. Hotchi, Y. Irie, F. Noda, T. Takayanagi
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Machida, I. Sakai
    KEK, Ibaraki
  The RCS(rapid cycling synchrotron) of J-PARC(Japan proton accelerator research complex) acts as an injector to the main ring as well as a high-power beam for the spallation neutron source at a repetition rate of 25 Hz, where at present the injection and the extraction beam energy are chosen to be 0.181 GeV and 3.0 GeV, respectively. The present work concerns on the present design and calculations for the injection-dump line of the RCS, which includes, 1) an accurate aperture list of all elements taking into account a wide range of the betatron tune, effect of changing injection modes, multiple trajectories of different particles after the charge-exchange foil( like H0 from the H- and H- beam itself)and 2) an accurate estimation of the uncontrolled beam losses especially from the H0-excited states, multiple coulomb scattering at the charge-exchange foil and also the lorentz stripping loss at the septum magnets so as to optimize them concerning mainly the radiation issues as well as for the hands-on maintenance.  
 
FPAE074 Beam Parameter Measurement and Control at the SNS Target target, diagnostics, quadrupole, SNS 3913
 
  • M.A. Plum, M. Holding, T. McManamy
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The spallation neutron production target at the SNS facility is designed for 1.4 MW beam power. Both beam position and profile must be carefully controlled within narrow margins to avoid damage to the target. The position must be within 2 mm of the target center, and 90% of the beam must be within the nominal 70 mm x 200 mm spot size, without exceeding 0.18 A/m2 peak beam current density. This is a challenging problem, since most of the diagnostics are 9 m upstream of the target, and because the high beam power limits the lifetime of intercepting diagnostics. Our design includes a thermocouple halo monitor approximately 2 m upstream of the target face, and a beam position monitor, an insertable harp profile monitor, and a beam shape monitor approximately 9 m upstream. In this paper we will discuss our strategy to commission the beam delivery system and to meet target requirements during nominal operation.

 
 
FPAE077 LSP Simulations of the Neutralized Drift Compression Experiment ion, simulation, focusing, plasma 4006
 
  • C.H. Thoma, D.R. Welch
    ATK-MR, Albuquerque, New Mexico
  • S. Eylon, E. Henestroza, P.K. Roy, S. Yu
    LBNL, Berkeley, California
  • E.P. Gilson
    PPPL, Princeton, New Jersey
  Funding: Work supported by the VNL for HIF through PPPL and LBNL.

The Neutralized Drift Compression Experiment (NDCX) at Lawrence Berkeley National Laboratory involves the longitudinal compression of a singly-stripped K ion beam with a mean energy of 250 keV in a meter long plasma. We present simulation results of compression of the NDCX beam using the PIC code LSP. The NDCX beam encounters an acceleration gap with a time-dependent voltage that decelerates the front and accelerates the tail of a 500 ns pulse which is to be compressed 110 cm downstream. The simulations model both ideal and experimental voltage waveforms. Results show good longitudinal compression without significant emittance growth.

 
 
FPAP013 Emittance Growth Caused by Electron Cloud Below the “Fast TMCI” Threshold: Numerical Noise or True Physics? electron, simulation, proton, synchrotron 1344
 
  • E. Benedetto, E. Benedetto
    Politecnico di Torino, Torino
  • G. Franchetti
    GSI, Darmstadt
  • K. Ohmi
    KEK, Ibaraki
  • D. Schulte, F. Zimmermann
    CERN, Geneva
  Simulations show a persisting slow emittance growth for electron cloud densities below the threshold of the fast Transverse Mode Coupling type instability, which could prove important for proton beams with negligible radiation damping, such as in the LHC. We report on a variety of studies performed to quantify the contributions to the simulated emittance growth from numerical noise in the PIC module and from an artificial resonance excitation due to the finite number of kicks per turn applied for modeling the cloud-bunch interaction.  
 
FPAP018 Luminosity Loss Due to Beam Distortion and the Beam-Beam Instability luminosity, resonance, simulation, electron 1586
 
  • J. Wu, A. Chao, T.O. Raubenheimer, A. Seryi
    SLAC, Menlo Park, California
  • C.K. Sramek
    Rice University, Houston, Texas
  Funding: Work is supported by the U.S. Department of Energy under contract DE-AC02-76SF00515.

In a linear collider, sources of emittance dilution such as transverse wakefields or dispersive errors will couple the vertical phase space to the longitudinal position within the beam (the so-called ‘banana effect'). When the Intersection Point (IP) disruption parameter is large, these beam distortions will be amplified by a single bunch kink instability which will lead to luminosity loss. We study this phenomena both analytically using linear theory and via numerical simulation. In particular, we examine the dependence of the luminosity loss on the wavelength of the beam distortions and the disruption parameter. This analysis may prove useful when optimizing the vertical disruption parameter for luminosity operation with given beam distortions.

 
 
FPAP022 Long Time Simulation of LHC Beam Propagation in Electron Clouds space-charge, simulation, electron, injection 1769
 
  • B. Feng, A.F. Ghalam, T.C. Katsouleas
    USC, Los Angeles, California
  • E. Benedetto, F. Zimmermann
    CERN, Geneva
  • V.K. Decyk, W.B. Mori
    UCLA, Los Angeles, California
  In this report we show the simulation results of single-bunch instabilities caused by interaction of a proton beam with an electron cloud for the Large Hadron Collider (LHC) using the code QuickPIC [1]. We describe three new results: 1) We test the effect of the space charge of the beam on itself; 2) we add the effect of dispersion in the equation of motion in the x direction, and 3) we extend previous modeling by an order of magnitude (from 50ms to 500ms) of beam circulation time. The effect of including space charge is to change the emittance growth by less than a few percent. Including dispersion changes the plane of instability but keeps the total emittance approximately the same. The longer runs indicate that the long term growth of electron cloud instability of the LHC beam cannot be obtained by extrapolating the results of short runs.  
 
FPAP036 Beam Transport in a Compact Dielectric Wall Induction Accelerator System for Pulsed Radiography cathode, beam-transport, induction, simulation 2437
 
  • J.F. McCarrick, G.J. Caporaso, Y.-J. Chen
    LLNL, Livermore, California
  Funding: This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

Using dielectric wall accelerator technology, we are developing a compact induction accelerator system primarily intended for pulsed radiography. The accelerator would provide a 2-kA beam with an energy of 8 MeV, for a 20-30 ns flat-top. The design goal is to generate a 2-mm diameter, 10-rad x-ray source. We have a physics design of the system from the injector to the x-ray converter. We will present the results of injector modeling and PIC simulations of beam transport. We will also discuss the predicted time integrated spot and the on-axis x-ray dose.

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

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

 
 
FPAT042 Beam Dynamics and Pulse Duration Control During Final Beam Bunching in Driver System for Heavy Ion Inertial Fusion lattice, focusing, beam-transport, bunching 2735
 
  • T. Kikuchi, S. Kawata, T. Someya
    Utsunomiya University, Utsunomiya
  • K. Horioka, M. Nakajima
    TIT, Yokohama
  • T. Katayama
    CNS, Saitama
  Beam dynamics is investigated by multi-particle simulations during a final beam bunching in a driver system for heavy ion inertial fusion (HIF). The longitudinal bunch compression causes the beam instability induced by the strong space charge effect. The multi-particle simulation can indicate the emittance growth due to the longitudinal bunch compression. Dependence in the beam pulse duration is also investigated for effective pellet implosion in HIF. Not only the spatial nonuniformity of the beam illumination, but also the errors of the beam pulse duration cause changes of implosion dynamics. The allowable regime of the beam pulse duration for the effective fusion output becomes narrow with decreasing the input beam energy. The voltage accuracy requirement at the beam velocity modulator is also estimated for the final beam bunching. It is estimated that the integrated voltage error is allowable as a few percent.  
 
FPAT043 Application of Selected Momentum Correction Method Using Induction Voltage Modulator induction, storage-ring, injection, ion 2762
 
  • T. Kikuchi, S. Kawata
    Utsunomiya University, Utsunomiya
  • K. Horioka
    TIT, Yokohama
  • T. Katayama
    CNS, Saitama
  A method for momentum correction of a selected beam particle using a controllable induction voltage modulator is proposed for a low flux ion beam. The corrected ion beam has a small momentum error restricted by a detection error at a kinetic energy analyzer and a voltage fluctuation at the induction voltage modulator. The application of this selected momentum correction scheme is discussed by using numerical simulations.  
 
FPAT058 Creating EPICS Soft Channels the Easy Way with sddspcas: Features and Applications quadrupole, simulation, lattice, photon 3429
 
  • R. Soliday, M. Borland
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Using sddspcas, a portable channel access server that is configured by SDDS input files, it is relatively simple to create process variables (PVs). It can be run in a standalone mode or it can be run so that the PVs are checked to ensure that they don’t conflict with other IOCs or portable channel access servers. It can also be run using the Run Control facility to prevent additional instances of the same sddspcas from being run. The SDDS configuration file provides the PV names, upper and lower limits, units, element counts if the PVs are waveforms, and the types of PVs. Valid types include various precision floats and integers as well as strings. One simple application of this program is that software developers can quickly test their code without requiring the coordination needed to update an IOC database to create PVs. Further details of the features, configuration, and applications of sddspcas will be discussed.

 
 
FPAT089 A Parallel Simplex Optimizer and Its Application to High-Brightness Storage Ring Design dynamic-aperture, storage-ring, optics, target 4230
 
  • H. Shang, M. Borland
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Optimization is commonly used in accelerator design to find linear optics solutions. Such optimizations are usually fairly fast as linear optics computations are themselves fast. For high-brightness storage rings, optimization of nonlinear elements (e.g., sextupoles) is also important in obtaining sufficient dynamic aperture. However, this can be very time onsuming as the basic calculations are time consuming. We have developed an efficient parallel Simplex optimizer that runs on a Linux cluster. It can optimize the result of running essentially any program or script that returns a penalty function value. We have used this optimizer with elegant to optimize dynamic aperture of storage ring designs. We discuss the optimization algorithm and performance, design of penalty functions, and optimization results.

 
 
FOAA001 New Technology in Hydrogen Absorbers for Muon Cooling Channels simulation, linac, proton, scattering 84
 
  • M.A.C. Cummings
    Northern Illinois University, DeKalb, Illinois
  Funding: National Science Foundation.

Ionization cooling is the only technique fast enough to cool and focus muons for neutrino factories and muon colliders, and hydrogen is the optimal material for maximum cooling and minimal multiple scattering. Liquid hydrogen absorber R & D for the Muon Colloboration has proceeded on parallel and complementary fronts. The continuing LH2 absorber engineering and technical developments by the MuCool group conducted by ICAR* institutions (NIU, IIT and UIUC), the University of Mississippi and Oxford University, in cooperation with Fermilab, will be summarized, including results from the first hydrogen absorber tests at the newly constructed FNAL Mucool Test Area (MTA). The program includes designs for the high-powered test of an absorber prototype (external heat exchange) at the MTA which are nearing completion to be installed by summer 2005, an alternative absorber design (internal heat exchange) being finalized for the approved cooling experiment (MICE) at Rutherford-Appleton Laboratory, and a novel idea for gaseous hydrogen absorbers being developed at Fermilab for a high powered test at the MTA in 2006.

*Illinois Consortium for Accelerator Research.

 
 
FOAB009 The Frankfurt Funneling Experiment rfq, ion, linac, ion-source 677
 
  • H. Zimmermann, U. Bartz, D. Ficek, P. Fischer, N. Mueller, A. Schempp, J. Thibus, M. Vossberg
    IAP, Frankfurt-am-Main
  Funding: BMBF

Funneling is a technique to multiply beam currents of rf-accelerators in several stages at low energies to prevent problems with space charge. The Frankfurt Funneling Experiment is a prototype of such a stage. Two beams accelerated in a Two-Beam RFQ are combined to one beam axis with a funneling deflector. The last part of the RFQ electrodes of our Two-Beam RFQ has been replaced to achieve a 3d focus of both beams at the beam crossing point behind the RFQ in the center of the deflector. A newly designed multi cell funneling deflector and first results of the new experimental set-up will be presented.

 
 
FOAB010 Present Status of Photo-Cathode RF Gun System and Its Applications laser, electron, injection, gun 710
 
  • R. Kuroda, Y. Hama, K. Hidume, M. Kawaguchi, R. Moriyama, T. Saito, K. Sakaue, M. Washio
    RISE, Tokyo
  • H. Hayano, J.U. Urakawa
    KEK, Ibaraki
  • S. Kashiwagi
    ISIR, Osaka
  High quality electron beam generation using photo-cathode rf gun system and its applications have been developed at Waseda University. This system can generate up to 4.6 MeV low emittance electron beam. It is applied for soft X-ray generation using laser Compton scattering and pulse radiolysis experiments based on the pump-probe technique. In the former, Compton scattering experiments between about 4.6 MeV electron beam and 1047 nm laser beam is performed at 20 degrees interaction angle, so that about 370 eV soft X-ray is generated. In the latter, the electron beam is used for the pump beam and the probe beam is generated as white light by concentrating laser beam on the water cell, so that the measurement with about 30 ps (FWHM) time resolution of the pulse radiolysis system is demonstrated for the absorption of hydrated electrons. In this conference, we will present the experimental results, status of this system and future applications.  
 
FOAD002 Ultra-High Density Electron Beams for Beam Radiation and Beam Plasma Interaction electron, focusing, simulation, plasma 145
 
  • S.G. Anderson, J. Brown, D.J. Gibson, F.V. Hartemann, J.S. Jacob, A.M. Tremaine
    LLNL, Livermore, California
  • P. Frigola, J. Lim, J.B. Rosenzweig, G. Travish
    UCLA, Los Angeles, California
  • P. Musumeci
    INFN-Roma, Roma
  Funding: This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

Current and future applications of high brightness electron beams, which include advanced accelerators such as the plasma wake-field accelerator (PWFA) and beam-radiation interactions such as inverse-Compton scattering (ICS), require both transverse and longitudinal beam sizes on the order of tens of microns. Ultra-high density beams may be produced at moderate energy (50 MeV) by compression and subsequent strong focusing of low emittance, photoinjector sources. We describe the implementation of this method used at LLNL’s PLEIADES ICS x-ray source in which the photoinjector-generated beam has been compressed to 300 fsec duration using the velocity bunching technique and focused to 20 μm rms size using an extremely high gradient, permanent magnet quadrupole (PMQ) focusing system.

 
 
FOAD005 Commissioning of the University of Maryland Electron Ring (UMER) injection, space-charge, quadrupole, dipole 469
 
  • S. Bernal, G. Bai, D.W. Feldman, R. Feldman, T.F. Godlove, I. Haber, J.R. Harris, M. Holloway, R.A. Kishek, J.G. Neumann, P.G. O'Shea, C. Papadopoulos, B. Quinn, D. Stratakis, K. Tian, J.C. Tobin Thangaraj, M. Walter, M. Wilson
    IREAP, College Park, Maryland
  • M. Reiser
    University Maryland, College Park, Maryland
  Funding: This work is funded by the U.S. Department of Energy under grants DE-FG02-94ER40855 and DE-FG02-92ER54178, and the office of Naval Research under grant N00014-02-1-0914.

The University of Maryland electron ring (UMER) is a low-energy, high current recirculator for beam physics research. The ring is completed for multi-turn operation of beams over a broad range of intensities and initial conditions. UMER is addressing issues in beam physics with relevance to many applications that rely on intense beams of high quality. Examples are advanced accelerators, FEL’s, spallation neutron sources and future heavy-ion drivers for inertial fusion. We review the motivation, ring layout and operating conditions of UMER. Further, we present a summary of beam physics areas that UMER is currently investigating and others that are part of the commissioning plan: from transverse beam dynamics (matching, halo formation, strongly asymmetric beams, space-charge waves, etc), longitudinal dynamics (bunch capture/shaping, evolution of energy spread, longitudinal space-charge waves, etc.) to future upgrades and planned research (acceleration and resonance traversal, modeling of galactic dynamics, etc.) We also emphasize the computer simulation work that is an integral part of the UMER project.