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linac

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MOPC002 Benchmark of Space Charge Simulations and Comparison with Experimental Results for High Intensity, Low Energy Accelerators space-charge, emittance, simulation, 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.

 
 
MPPE023 Improvement of the Longitudinal Beam Dynamics Tuning Procedure for the MSU RIA Driver Linac emittance, 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 lattice, emittance, 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.

 
 
MPPE035 Transfers from High Power Hadron Linacs to Synchrotrons proton, SNS, injection, acceleration 2375
 
  • G.P. Jackson
    Hbar Technologies, LLC, West Chicago, Illinois
  The Fermilab Proton Driver is an example of a high power H- linear accelerator proposed as a new source of high brightness protons for the Main Injector synchrotron. Because of the elevated radioactive activation of accelerator components associated with beam losses during injection and acceleration, extra attention must be paid to RF manipulations wherein small losses were once deemed acceptable. Especially when injecting into existing synchrotrons from upgraded injectors, instabilities and beam loading make loss free manipulations especially problematic. This paper discusses some options for reducing the losses associated with common longitudinal beam manipulations.  
 
MPPE063 Optimization of Steering Elements in the RIA Driver Linac focusing, simulation, lattice, quadrupole 3600
 
  • E.S. Lessner, V.S. Assev, P.N. Ostroumov
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy under contract W-31-109-ENG-38.

The driver linac of the projected RIA facility is a versatile accelerator, a 1.4-GV, CW superconducting linac designed to simultaneously accelerate several heavy-ion charge states, providing beams from protons at about 1 GeV to uranium at 400 MeV/u at power levels at a minimum of 100 kW and up to 400 kW for most beams. Acceleration of multiple-charge-state uranium beams places stringent requirements on the linac design. A steering algorithm was derived that fulfilled the driver’s real estate requirements, such as placement of steering dipole coils on SC solenoids and of beam position monitors outside cryostats, and beam-dynamics requirements, such as coupling effects induced by the focusing solenoids.* The algorithm has been fully integrated in the tracking code TRACK** and is used to study and optimize the number and position of steering elements that minimize the multiple-beam centroid oscillations and preserve the beam emittance under misalignments of accelerating and transverse focusing elements in the driver linac.

*E.S. Lessner and P.N. Ostroumov, Proceedings of the 9-th European Particle Accelerator Conference, July 2005, pp.1476-1478. **V.N. Aseev, P.N. Ostroumov, E.S. Lessner, and B. Mustapha, these proceedings.

 
 
MPPE081 The Comparison of a New Beam-Tracking Code to the Acceleration Test acceleration, simulation, dipole, injection 4072
 
  • K. Yamamoto, S. Yamada, K. Yamamoto
    NIRS, Chiba-shi
  • T. Hattori
    RLNR, Tokyo
  • M. Okamura
    RIKEN, Saitama
  A new beam-tracking code using a 3D electro-magnetic field map of a linac is being developed. In this code, beam dynamics including non-linear and dipole effects can be easily estimated based on simulated field maps provided by commercial 3D analysis software. To verify the code, we manufactured an IH-linac and acceleration test of the linac was carried out with proton beam. The simulated results were compared with the tested acceleration performances.  
 
MPPP009 Linac Coherent Light Source Longitudinal Feedback Model feedback, simulation, gun, electron 1156
 
  • J. Wu, P. Emma, L. Hendrickson
    SLAC, Menlo Park, California
  Funding: Work is supported by the US Department of Energy under contract DE-AC02-76SF00515.

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL). To ensure the vitality of FEL lasing, it is critical to preserve the high quality of the electron beam during acceleration and compression. The peak current and final energy are very sensitive to system jitter. To minimize this sensitivity, a longitudinal feedback system on the bunch length and energy is required, together with other diagnostics and feedback systems (e.g., on transverse phase space). In this paper, we describe a simulation framework, which includes a realistic jitter model for the LCLS accelerator system, the RF acceleration, structure wakefield, and second order optics. Simulation results show that to meet the tight requirements set by the FEL, such a longitudinal feedback system is mandatory.

 
 
MPPP016 Adaptive Feed Forward Beam Loading Compensation Experience at the Spallation Neutron Source Linac SNS, beam-loading, Spallation-Neutron-Source, klystron 1467
 
  • K.-U. Kasemir, M. Champion, M.T. Crofford, H. Ma
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

When initial beam studies at the Spallation Neutron Source (SNS) indicated a need for better compensation of the effects of beam loading, a succession of rapid-prototyping and experimentation lead to the development of a simple yet successful adaptive feed forward technique within a few weeks. We describe the process and first results.

 
 
MPPP035 Investigation of APS PAR Vertical Beam Instability ion, injection, synchrotron, electron 2393
 
  • C. Yao, Y.-C. Chae, N. Sereno, B.X. Yang
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

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

 
 
MPPT007 Design of the Pulse Bending Magnets for the Injection System of the 3-GeV RCS in J-PARC injection, power-supply, extraction, beam-losses 1048
 
  • T. Takayanagi, Y. Irie, J. Kamiya
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • T. Kawakubo, I. Sakai
    KEK, Ibaraki
  The pulse bending magnets for the injection system of the 3-GeV RCS in J-PARC has been designed using a 3D magnetic analysis code. The injection system consists of the pulse bending magnets for the injection bump orbit, which are four horizontal bending magnets (shift bump), four horizontal painting magnets (h-paint bump), and two vertical painting magnets (v-paint bump). The injection beam energy and the extraction beam power are 400 MeV and 1 MW at 25-Hz repetition rate, respectively. The beam orbit area with a full acceptance beam of the injection beam, painting beam and the circulating beam at the shift bump points is a 400 mm width and a 250 mm height.The shift bump has accomplished 1.0% good field region at 0.22 T.  
 
MPPT013 New Pulsed Orbit Bump Magnets for the Fermilab Booster Synchrotron booster, injection, vacuum, quadrupole 1341
 
  • J.R. Lackey, D.J. Harding, J.A. John, V.S. Kashikhin, A. Makarov, E. Prebys
    Fermilab, Batavia, Illinois
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-76CH03000.

The beam from the Fermilab Linac is injected onto a bump in the closed orbit of the Booster Synchrotron where a carbon foil strips the electrons from the Linac’s negative ion hydrogen beam. Although the Booster itself runs at 15Hz, heat dissipation in the orbit bump magnets has been one limitation to the fraction of the cycles that can be used for beam. New, 0.28T pulsed window frame dipole magnets have been constructed that will fit into the same space as the old ones, run at the full repetition rate of the Booster, and provide a larger bump to allow a cleaner injection orbit. The new magnets use a high saturation flux density Ni-Zn ferrite in the yoke rather than laminated steel. The presented magnetic design includes two and three dimensional magnetic field calculations with eddy currents and ferrite nonlinear effects.

 
 
MOPB005 Advances in the Performance of the SNS Ion Source ion, ion-source, SNS, plasma 472
 
  • R.F. Welton, S.N. Murray, M.P. Stockli
    ORNL, Oak Ridge, Tennessee
  • R. Keller
    LBNL, Berkeley, California
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The ion source developed for the Spallation Neutron Source* (SNS) is a radio frequency, multi-cusp source designed to produce ~ 40 mA of H- with a normalized rms emittance of less than 0.2 pi mm mrad. To date the source has been utilized in the commissioning of the SNS accelerator, delivering beams of 10-50 mA with duty-factors of typically ~0.1% for operational periods of several weeks and availabilities now ~99%. Ultimately the SNS facility will require beam duty-factors of 6% (1 ms pulse length, 60 Hz repetition rate, 21 day run-period). Over the last year, several experiments were performed in which the ion source was continuously operated at full duty-factor and maximum beam current on a dedicated test stand. Recently, a breakthrough in our understanding of the Cs release process has led to the development of a new source conditioning technique which resulted in a dramatic increase in beam persistence with time. Average H- beam attenuation rates have been improved from ~5 mA/day to ~0.4 mA/day, allowing beams in excess of 30 mA to be delivered continuously at full duty factor for periods of ~20 days. Prior to this development, full duty factor beams could only be sustained for periods of several hours.

 
 
MOPB008 Temporal E-Beam Shaping in an S-Band Accelerator laser, electron, emittance, 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.

 
 
MOPB009 Review of the Production Process of TTF and PITZ Photocathodes cathode, gun, electron, monitoring 671
 
  • D. Sertore, P. Michelato, L. Monaco
    INFN/LASA, Segrate (MI)
  • A. Bonucci
    SAES Getters S.p.A., Lainate
  • J.H. Han
    DESY Zeuthen, Zeuthen
  • S. Schreiber
    DESY, Hamburg
  In the present article, the production process of the photocathodes for the TESLA Test Facility (TTF) at DESY Hamburg and the Photo Injector Test Facility at DESY-Zeuthen (PITZ) is reviewed in order to highlight key elements for the final photocathode performances. Since the first photocathode production in 1998, we have continuosly collected relevant paramenters of the cathode plugs and deposition process. These data are now critically analized in view of an optimization of the photocathode performances for the next generation of high brilliance sources.  
 
TOAA008 Progress and Status in SNS Magnet Measurements at ORNL dipole, quadrupole, SNS, permanent-magnet 609
 
  • T. Hunter, SH. Heimsoth, DL. Lebon, RM. McBrien, J.-G. Wang
    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 (SNS) contains more than 600 magnets. Among them, about 400 magnets for the Linac and transfer lines are being measured on site at Oak Ridge National Laboratory. These magnets include Permanent Magnet Quadrupoles, Electro-magnetic Quadrupoles, Dipoles and Correctors. The Permanent Magnet Quadrupoles are installed in the Drift Tube Linac (DTL) and are the only Permanent Magnets in the machine. These measurements are for magnets installed in the DTL, Coupled Cavity Linac (CCL), Superconducting Linac (SCL), High Energy Beam Transport (HEBT), and the Ring to Target Beam Transport (RTBT) line. All magnets have met specifications. Approximately three fourths of the magnets have so far been measured and installed. This presentation outlines the magnet measurements for SNS at ORNL and overviews the activities and accomplishments to date.

 
 
TPAE028 Beam Dynamics Studies for a Laser Acceleration Experiment gun, space-charge, laser, emittance 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.

 
 
TPAE060 Planned Enhanced Wakefield Transformer Ratio Experiment at Argonne Wakefield Accelerator laser, simulation, electron, pick-up 3487
 
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • P.A. Avrakhov
    LPI, Moscow
  • W. Gai, C.-J. Jing, R. Konecny, J.G. Power
    ANL, Argonne, Illinois
  Funding: U.S. Department of Energy.

In this paper, we present a preliminary experimental study of a wakefield accelerating scheme that uses a carefully spaced and current ramped electron pulse train to produce wakefields that increases the transformer ratio much higher than 2. A dielectric structure was designed and fabricated to operate at 13.625 GHz with dielectric constant of 15.7. The structure will be initially excited by two beams with first and second beam charge ratio of 1:3. The expected transformer ratio is 3 and the setup can be easily extend to 4 pulses which leads to a transformer ratio of more than 6. The dielectric structure cold test results show the tube is within the specification. A set of laser splitters was also tested to produce ramped bunch train of 2 - 4 pulses. Overall design of the experiment and initial results will be presented.

 
 
TPAP043 Electron Cooling of RHIC electron, ion, emittance, 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.

 
 
TPAT005 Start to End Error Study for the SPIRAL2 Linac quadrupole, emittance, 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.

 
 
TPAT008 Numerical Dispersion Error Reduction in EM Calculations for Accelerators simulation, electromagnetic-fields, electron, single-bunch 1114
 
  • T. Lau, E. Gjonaj, T. Weiland
    TEMF, Darmstadt
  • I. Zagorodnov
    DESY, Hamburg
  Funding: Deutsches Elektronen-Synchrotron DESY

In this contribution novel numerical algorithms with no dispersion along the beam axis are investigated. This property is of interest for the long-time calculation of electromagnetic fields in accelerators. Instead of increasing the spatial stencil of the Yee scheme the compared methods modify the time-stepping algorithm.The results are compared on several test examples. As a practical application the electromagnetic field of a very short bunch inside a cavity is calculated.

 
 
TPAT028 TRACK: The New Beam Dynamics Code simulation, space-charge, ion, multipole 2053
 
  • B. Mustapha, V.N. Aseev, E.S. Lessner, P.N. Ostroumov
    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 new ray-tracing code TRACK was developed* to fulfill the special requirements of the RIA accelerator systems. The RIA lattice includes an ECR ion source, a LEBT containing a MHB and a RFQ followed by three SC linac sections separated by two stripping stations with appropriate magnetic transport systems. No available beam dynamics code meet all the necessary requirements for an end-to-end simulation of the RIA driver linac. The latest version of TRACK was used for end-to-end simulations of the RIA driver including errors and beam loss analysis.** In addition to the standard capabilities, the code includes the following new features: i) multiple charge states ii) realistic stripper model; ii) static and dynamic errors iii) automatic steering to correct for misalignments iv) detailed beam-loss analysis; v) parallel computing to perform large scale simulations. Although primarily developed for simulations of the RIA machine, TRACK is a general beam dynamics code. Currently it is being used for the design and simulation of future proton and heavy-ion linacs at TRIUMF, Fermilab, JLAB and LBL.

*P.N. Ostroumov and K.W. Shepard. Phys. Rev. ST. Accel. Beams 11, 030101 (2001). **P.N. Ostroumov, V. N. Aseev, B. Mustapha. Phys. Rev. ST. Accel. Beams, Volume 7, 090101 (2004).

 
 
TPAT029 RIA Beam Dynamics: Comparing TRACK to IMPACT simulation, lattice, injection, ion-source 2095
 
  • B. Mustapha, V.N. Aseev, P.N. Ostroumov
    ANL, Argonne, Illinois
  • J. Qiang, R.D. Ryne
    LBNL, Berkeley, California
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38.

In order to benchmark the newly developed beam dynamics code TRACK we have performed comparisons with well established existing codes. During code development, codes like TRANSPORT, COSY, GIOS and RAYTRACE were used to check TRACK's implementation of the different beam line elements. To benchmark the end-to-end simulation of the RIA driver linac, the simulation of the low-energy part (from the ion source to the entrance of the SC linac) was compared with PARMTEQ and found to agree well. For the simulation of the SC linac the code IMPACT is used. Prior to these simulations, the code IMPACT had to be updated to meet the special requirements of the RIA driver linac. Features such as multiple charge state acceleration, stripper simulation and beam collimation were added to the code. IMPACT was also modified to support new types of rf cavities and to include fringe fields for all the elements. This paper will present a comparison of the beam dynamics simulation in the RIA driver linac between the codes TRACK and IMPACT. A very good agreement was obtained which represents another validation of both codes.

 
 
TPAT030 Transverse Beam Matching Application for SNS emittance, SNS, 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 emittance, 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, emittance, plasma 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.

 
 
TPAT038 Chaos in Time-Dependent Space-Charge Potentials space-charge, emittance, 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.  
 
TPAT048 The Transverse Nonlinear Tune Shift as Stabilising Factor in Halo Creation in Space Charge Dominated Beam resonance, space-charge, focusing, quadrupole 3004
 
  • N.E. Vasyukhin, Y. Senichev, R. Tölle
    FZJ, Jülich
  Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" program (CARE, contract number RII3-CT-2003-506395).

One of the most important problems for space charge dominated beam in the low energy part of superconducting linac is halo creation. Many authors show one of the key effects in halo creatiation is parametric resonance due to the mismatched beta-function oscillation (between core and particle). To estimate parametric resonance conditions the nonlinear tune shift for binomial distributed beam is described theoretically in this article. Simultaneously the beam dynamics simulation 3D PIC code was developed. The transverse oscillation frequencies compared with parametric resonance criteria. As a result the recommendation for space charge shift is concluded to minimize halo creation.

 
 
TPAT049 Comparison of Beam Dynamic in Different Superconducting Options of Low Energy High Intense Linac focusing, quadrupole, simulation, space-charge 3058
 
  • N.E. Vasyukhin, Y. Senichev, R. Tölle
    FZJ, Jülich
  Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" program (CARE, contract number RII3-CT-2003-506395).

At present the superconducting proton linacs have obvious applications in energy range ~100-1000 MeV. For the lower energy the comprehensive investigations are required. In this article the various variants of superconducting options from 3MeV up to 100MeV are discussed. The considered variants include both the conventional combination of half-wave and spoke cavity with quadrupoles and new schemes. In conclusion the table of major parameters for different structures is given.

 
 
TPAT050 Beam Dynamics Design of the L3BT for J-PARC injection, space-charge, simulation, emittance 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.  
 
TPAT097 CLIC Drive Beam and LHC Based FEL-Nucleus Collider collider, photon, electron, ion 4320
 
  • O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  • H.-H. Braun, R. Corsini
    CERN, Geneva
  • S. Sultansoy
    Gazi University, Faculty of Science and Arts, Ankara
  Funding: Ankara University, Ankara, TURKEY.

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

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

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

 
 
TOAB004 An Optimized Low-Charge Configuration of the Linac Coherent Light Source emittance, 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.

 
 
TOAB005 4GLS and the Energy Recovery Linac Prototype Project at Daresbury Laboratory gun, beam-transport, undulator, laser 431
 
  • E.A. Seddon, M.W. Poole
    CCLRC/DL, Daresbury, Warrington, Cheshire
  4GLS is a novel next generation proposal for a UK national light source to be sited at Daresbury Laboratory. It is based on a superconducting energy recovery linac (ERL) with capabilities for both high average current spontaneous photon sources (undulators and bending magnets) and high peak current free electron lasers. Key features of the proposal are a high gain, seeded FEL amplifier to generate XUV radiation and the prospect of advanced dynamics work arising from its unique combinations of sources and its femtosecond pulse structure. To meet the challenging accelerator technology involved, a significant R&D programme has commenced and a major part of this is a 35 MeV demonstrator, the ERL Prototype (ERLP), currently under construction. This paper summarises the 4GLS design activities, describes the ERLP in detail and explains the 4GLS project status and plans.  
 
TOAD003 Development of the Beam Diagnostics System for the J-PARC Rapid-Cycling Synchrotron injection, proton, vacuum, beam-losses 299
 
  • N. Hayashi, S.H. Hiroki, J. Kishiro, Y.T. Teruyama, R. Toyokawa
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • D.A. Arakawa, S. Lee, T. Miura, T. Toyama
    KEK, Ibaraki
  Development of the beam diagnostics system for the J-PARC (Japan Proton Accelerator Research Complex) Rapid-Cycling Synchrotron is described. The system consists of Beam Position Monitor (BPM), Beam Loss Monitor (BLM), Current monitors (DCCT, SCT, MCT, FCT, WCM), Tune meter system, 324MHz-BPM, Profile monitor, and Halo monitor. BPM electrode is electro-static type and its electronics is designed for both COD and turn-by-turn measurements. Five current monitors have different time constants in order to cover wide frequency range. The tune meter is consisted of RFKO and the beam pick-up electrode. For the continuous injected beam monitoring, 324MHz-BPM detects Linac frequency. Two types of profile monitor are multi-wire for low intensity tuning and the residual gas monitor for non-destructive measurement.  
 
TOPB004 Overview of Energy Recovery Linacs electron, emittance, 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.

 
 
TPPE006 Radioactive Beams from 252CF Fission Using a Gas Catcher and an ECR Charge Breeder at ATLAS ion, shielding, ion-source, beam-transport 1000
 
  • R.C. Pardo, S.I. Baker, A.A.H. Hecht, E.F. Moore, G. Savard
    ANL, Argonne, Illinois
  Funding: Department of Energy Office of Nuclear Science.

An upgrade to the radioactive beam capability of the ATLAS facility has been proposed using 252Cf fission fragments thermalized and collected into a low-energy particle beam using a helium gas catcher. In order to reaccelerate these beams an existing ATLAS ECR ion source will be reconfigured as a charge breeder source. A 1Ci 252Cf source is expected to provide sufficient yield to deliver beams of up to ~106 far from stability ions per second on target. A facility description, the expected performance and the expected performance will be presented in this paper. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract W-31-109-ENG-38.

 
 
TPPE007 Energy Correction for High Power Proton/H Minus Linac Injectors SNS, injection, space-charge, feedback 1075
 
  • D. Raparia, Y.Y. Lee, J. Wei
    BNL, Upton, Long Island, New York
  High-energy proton/H minus (> GeV) linear accelerators suffer from energy jitter due to RF amplitude and phase stability. For high-power operations, such energy jitter often results in beam losses at more than 1 W/m level required for hands-on maintenance. Depending upon the requirements for next accelerator in the chain, this energy jitter may or may not require correction. This paper discusses the sources of energy jitter and correction feasibility with specific examples of the Spallation Neutron Source linac and a higher-energy H minus linac.  
 
TPPE036 Progress of the BEPCII Linac Upgrade positron, electron, gun, target 2416
 
  • G. Pei
    IHEP Beijing, Beijing
  BEPCII-an upgrade project of the BEPC is a factory type of e+e- collider. It requires its injector linac to have a higher beam energy (1.89 GeV) for on-energy injection and a higher beam current (40 mA e+ beam) for a higher injection rate (=50 mA/min.). The low beam emittance (1.6pmm-mrad for e+ beam, and 0.2pmm-mrad for 300 mA e- beam) and low beam energy spread (±0.5%) are also required to meet the storage ring acceptance. Hence we need a new electron gun system, a new positron source, a much higher power and more stable RF system with its phasing loops, and a new beam tuning system with orbit correction. Up to date, all system design and fabrication work have been completed. And in five months from May 1st of 2004, the positron production system–from the electron gun to the positron source, has been installed into the tunnel. In this paper, we will introduce major upgrades of each system, and present the recent beam commissioning.  
 
TPPE040 RF and Magnetic Measurements on the SPARC Photoinjector and Solenoid at UCLA gun, emittance, cathode, coupling 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 emittance, electron, space-charge, 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, emittance, quadrupole, 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).

 
 
TPPE048 The Injection System of SAGA Light Source injection, septum, storage-ring, kicker 3007
 
  • Y. Iwasaki, S. Koda, T. Okajima, Y. Takabayashi, T. Tomimasu, K. Yoshida
    Saga Synchrotron Light Source, Industry Promotion Division, Saga City
  • H. Ohgaki
    Kyoto IAE, Kyoto
  Saga light Source is a 1.4-GeV electron storage ring with a circumference of 75.6m. The injector is a 250-MeV linac producing 1 ms macro-pulse with a peak current of 12mA and repetition rate of 1Hz. The output beam from the linac is transported though a transport line, and injected into the ring though a septum magnet with a bending angle of 20-degree. The transport line consists of two bending magnets, two quadrupole doublelets, and a quadrupole singlet. The bump orbit is formed by four kicker magnets, two of which are installed at both sides of septum magnet, and other two are positioned apart by one magnet cell of the ring. They are excited by sinusoidal electric currents with a half width of 0.5 ms. The beam optics for the injection trajectory is computed and shown at control room, the parameters for which are provided directly from the power supply control server PC. The operator is able to see real-time result of the beam trajectory calculation. This tool is quite effective to optimize the magnets parameter setting. The commissioning of the light source was started in August 2004, and 250-MeV electrons ware stored first time on November 2004.  
 
TPPE049 Synchronizaiton Between Laser and Electron Beam at Photocathode RF Gun laser, electron, gun, cathode 3079
 
  • A. Sakumi, A. Fukasawa, Y. Muroya, T. Ueda, M. Uesaka, K. Yoshii
    UTNL, Ibaraki
  • K. Dobashi
    NIRS, Chiba-shi
  • N. Kumagai, H. Tomizawa
    JASRI/SPring-8, Hyogo
  • J.U. Urakawa
    KEK, Ibaraki
  The chemical reactions of hot, room temperature and critical water in a time-range of picosecond and sub-picosecond have been carried out by the 18 MeV S-band linac and a Mg photocathode RF gun with the irradiation of third harmonic Ti: Sapphire laser, at Nuclear Engineering Research Laboratory (NERL), the University of Tokyo. Although this short bunch and 100 fs laser light are enough to perform the experiment of radiation chemistry in the time-range of sub-picosecond, the total time-resolution become worse by the instability of synchronization between laser and radio frequency of linac. We found that the fluctuation of room temperature causes the instability, particularly the cycle of turning on/off of the air-conditioner. It is shown that 0.3 °C (peak-to-peak) fluctuation of the laser-room temperature have approximately corresponded to the instability of 6 ps. We are trying to decrease the fluctuation of the room temperature, together with the local temperature stability of the Ti: Sapphire crystal, the pumping laser. Furthermore, we will develop the feed back system for reducing the instability of the synchronization.  
 
TPPE059 New Electron Gun System for BEPCII gun, electron, emittance, simulation
 
  • 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.  
 
TPPP001 Design of Damping Ring for SuperKEKB emittance, dynamic-aperture, damping, 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.  
 
TPPP016 Beam Physics for the 12 GeV CEBAF Upgrade Project polarization, recirculation, optics, damping 1482
 
  • L. Merminga, J. F. Benesch, S.A. Bogacz, Y.-C. Chao, A. Freyberger, J.M. Grames, L. Harwood, R. Kazimi, G.A. Krafft, M. Spata, M. Tiefenback, M. Wiseman, B.C. Yunn, Y. Zhang
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by DOE Contract DE-AC05-84ER40150.

Beam physics aspects of the 12 GeV Upgrade of CEBAF are presented. The CEBAF Upgrade to 12 GeV is achieved via 5.5 recirculations through the linacs, and the installation of 10 new high-gradient cryomodules. A new experimental hall, Hall D, is envisioned at the end of North Linac. Simulation results for straight-through and recirculated injectors are summarized and compared. Beam transport designs are discussed and evaluated with respect to matching and beam breakup (BBU) optimization. Effects of synchrotron radiation excitation on the beam properties are calculated. BBU simulations and derived specifications for the damping of higher order modes of the new 7-cell cavities are presented. The energies that provide longitudinal polarization in multiple experimental halls simultaneously are calculated. Finally, a detailed optics design for the Hall D transport line has been obtained.

 
 
TPPP032 Proposal for a Multi-Use Test Beam Area in the SLAC B-Line optics, quadrupole, target, emittance 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.

 
 
TPPP033 Cavity Alignment Using Beam Induced Higher Order Modes Signals in the TTF Linac dipole, alignment, single-bunch, higher-order-mode 2284
 
  • M.C. Ross, J.C. Frisch, K.E. Hacker, R.M. Jones, D.J. McCormick, C.L. O'Connell, T.J. Smith
    SLAC, Menlo Park, California
  • N. Baboi, M.W. Wendt
    DESY, Hamburg
  • O. Napoly, R. Paparella
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  Funding: DE-AC02-76SF00515.

Each nine cell superconducting accelerator cavity in the TESLA Test Facility (TTF) at DESY* has two higher order mode (HOM) couplers that efficiently remove the HOM power.** They can also provide useful diagnostic signals. The most interesting modes are in the first 2 cavity dipole passbands. They are easy to identify and their amplitude depends linearly on the beam offset from the cavity axis making them excellent beam position monitors (BPM). By steering the beam through an eight-cavity cryomodule, we can use the HOM signals to estimate internal residual alignment errors and minimize wakefield related beam emittance growth. We built and commissioned a four channel heterodyne receiver and time-domain based waveform recorder system that captures information from each mode in these two bands on each beam pulse. In this paper we present an experimental study of the single-bunch generated HOM signals at the TTF linac including estimates of cavity alignment precision and HOM BPM resolution.

*P. Piot, DESY-TESLA-FEL-2002-08. **R. Brinkmann et al. (eds.), DESY-2001-011.

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

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

 
 
TPPP047 New and Efficient Neutrino Factory Front-End Design target, proton, factory, bunching 2986
 
  • J.C. Gallardo, J.S. Berg, R.C. Fernow, H.G. Kirk, R. Palmer
    BNL, Upton, Long Island, New York
  • D.V. Neuffer
    Fermilab, Batavia, Illinois
  • K. Paul
    Muons, Inc, Batavia
  Funding: Work supported by U.S. Department of Energy.

As part of the APS Joint Study on the Future of Neutrino Physics* we have carried out detailed studies of the Neutrino Factory front-end. A major goal of the new study was to achieve equal performance to our earlier feasibility studies** at reduced cost. The optimal channel design is described in this paper. New innovations included an adiabatic buncher for phase rotation and a simplified cooling channel with LiH absorbers. The linear channel is 295 m long and produces 0.17 muons per proton on target into the assumed accelerator transverse acceptance of 30 mm and longitudinal acceptance of 150 mm.

*APS Multi-Divisional Study of the Physics of Neutrinos, http://www.aps.org/neutrino/. **S.Ozaki, R.B.Palmer, M.Zisman and J.C.Gallardo, edts., Tech. Rep., BNL-52623 (2001), http://www.cap.bnl.gov/mumu/studyii/FS2-report.html.

 
 
TPPP053 Thin RF Windows for High-Pressure Gas-Filled Cavities vacuum, beam-cooling, collider, scattering 3224
 
  • M. Alsharo'a, R.P. Johnson
    Muons, Inc, Batavia
  • M. Gosz, D.M. Kaplan, S. Nair
    Illinois Institute of Technology, Chicago, Illinois
  • A. Moretti, G. Romanov
    Fermilab, Batavia, Illinois
  Funding: This work was supported in part by DOE STTR grant DE-FG02-02ER86145.

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

 
 
TPPT003 Development of a Normal Conducting CH-DTL proton, diagnostics, impedance, injection 883
 
  • G. Clemente, H. Podlech, U. Ratzinger, R. Tiede
    IAP, Frankfurt-am-Main
  • L. Groening
    GSI, Darmstadt
  • S. Minaev
    ITEP, Moscow
  Funding: GSI, EU (CARE, contract number RII3-CT-2003-506395).

The normal conducting "Crossbar H-Type" (CH) accelerating structure is a good candidate for pulsed, high intensity linac application, covering the energy range from 3 to 100 MeV. H Mode cavities are outstanding in the low-beta range with respect to shunt impedance, high acceleration fields, and compact design, That's why we propose to base the 70 ma, 70 MeV, 352 MHz proton linan for GSI FAIR project on that structure. The actual design consists of 11 CH-DTL's for a total length of around 25 m. Latest results from beam dynamics optimisation will be discussed. Moreover, this paper describes the CH-DTL cavity design with enphasis on the optimisation with MacroWave Studio (single cell cross section, as well as multi cell cavity simulation), and on the achieved progress in the development of mechanical design concepts. A stainless steel multicell model cavity is presently fabricated by our institute in collaboration with GSI, in order to investigate manufacturing and assembly details. Based on this experience, the design of a CH prototipe power cavity will be optimised.

 
 
TPPT004 A 175 MHz RFQ Design for IFMIF Project rfq, insertion, quadrupole, simulation 904
 
  • S. Maebara, S. Moriyama, M.S. Sugimoto
    JAERI, Ibaraki-ken
  • M.S. Saigusa, Y. Saitou
    Ibaraki University, Electrical and Electronic Eng., Ibaraki
  International Fusion Materials Irradiation Facility (IFMIF) is an accelerator-based neutron irradiation facility employing the D-Li stripping reaction, to produce the neutron field similar to the D-T Fusion reactor (2MW/m2,20 dpa/year for Fe). The required beam current of 250 mA is realized by two beam lines of 125mA, and the output energies at injector,RFQ and DTL were designed to be 0.1, 5 and 40 MeV,respectively. The operation frequency of 175MHz was selected to accelerate the large current of 125mA. After an intensive beam simulation, the RFQ with a total length of 12m was designed to keep the minimum emittance growth with the RF injection power of 2.3MW CW. For such a 175MHz RFQ, a design for RF input coupler with loop antenna and co-axial window, supplying RF power shared by 3 x 4 ports, was conducted by using the 3-D electromagnetic code of MW-Studio. In order to withstand the voltage exceeding 200kW CW per one loop antenna, the co-axial line of 4 1/16” diameter is necessary, and it is found that the electric field distortion factor less than 1% can be achieved in beam bore only by employing the 4-loop antenna configuration providing the same power for each quadrants.  
 
TPPT005 Dual Harmonic Operation with Broadband MA Cavities in J-PARC RCS impedance, acceleration, vacuum, injection 931
 
  • M. Yamamoto, M. Nomura, A. Schnase, F. Tamura
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Yoshii
    KEK, Ibaraki
  In the J-PARC RCS RF system, the fundamental rf acceleration voltage and the 2nd higher harmonic one are applied to each cavity. This is possible, because the magnetic alloy loaded cavities have a broadband characteristic and require no resonant frequency tuning. The tube amplifier provides both rf components. We calculate the operation of the tube under the condition of the dual harmonic, the non-pure resistive load and the class AB push-pull mode.  
 
TPPT006 Development of RF Input Coupler with a Coaxial Line TiN-Coated Against Multipactoring vacuum, simulation, electron, coupling 1006
 
  • T. Abe, T. Kageyama, H. Sakai, Y. Takeuchi
    KEK, Ibaraki
  In one of the normal-conducting RF cavities used in the KEKB operation, we observed an unexpected rise of the vacuum pressure at certain input-power levels with and without a beam current. From the simulation study, we identify the pressure rises as an effect of the multipactoring discharge in the coaxial line of the input coupler. According to the simulation results, we have decided to make TiN coating on the inner surface of the outer conductor to suppress the multipactoring. In this paper, the status of the development of the TiN-coated input coupler is reported including the recent results of the high-power tests.  
 
TPPT007 Application of Highly-Pure Copper Lining to Normal-Conducting RF Cavities for an Electron-Positron Super B Factory factory, target, resonance, coupling 1051
 
  • T. Abe, T. Kageyama
    KEK, Ibaraki
  • Z. Kabeya, T. Kawasumi
    MHI, Nagoya
  • T. Nakamura, K. Tsujimoto
    Asahi Kinzoku Co., Ltd., Gifu
  • K. Tajiri
    Churyo Engineering Co., Ltd., Nagoya
  We apply a new copper lining with a high purity and a high electric conductivity to normal-conducting RF cavities for an electron-positron super B factory, in which four-times more beam current is required to be stored than in the present KEK B factory (KEKB). The lining is produced first by electroplating in an acid copper sulfate bath without brightener nor other organic additives, where the current is periodically reversed (‘‘PR process''). Its electric conductivity is so high as to be comparable to that of the highest-class oxygen-free copper. Then the copper surface is electropolished to make it smoother. There are two differences between our application and the previous one to the accelerator components for J-Parc. The first one is the lining thickness; our target of 120um is much thinner. The second one is that we have no mechanical polishing on the electroplated surface before electropolishing. In this paper, results of the quantitative estimations of the quality factor on the electroplated pillbox test cavity are reported together with microscale investigations of the copper surfaces.  
 
TPPT009 High Gradient Study at KEK on X-Band Accelerator Structure for Linear Collider linear-collider, collider, cathode, vacuum 1162
 
  • T. Higo, M. Akemoto, A. Enomoto, S. Fukuda, H. Hayano, N.K. Kudo, S.M. Matsumoto, T. Saeki, N. Terunuma, N. Toge, K.W. Watanabe
    KEK, Ibaraki
  • T.S. Suehara
    University of Tokyo, Tokyo
  We have fabricated accelerator structures for linear collider of the warm X-band design. These were composed of high-precision-machined parts for reliable wake-field suppression and possible cheap mass production. The structure design is mostly based on GLC/NLC design in collaboration with SLAC but the fabrication and the high-power test are being performed at KEK to conclude the feasibility, though the application to the present linear collider project was terminated. In this paper are presented the high gradient performance of these structures, such as the initial conditioning characteristics, the stability under high-field operation and various characteristics at high-gradient operation. We conclude that the stability requirement for the linear collider of the warm X-band design is barely satisfied but the preservation of the stability over very long period of more than several years is to be further studied.  
 
TPPT011 R&D Status of C-Band Accelerating Section for SuperKEKB positron, klystron, luminosity, coupling 1233
 
  • T. Kamitani, N. Delerue, M. Ikeda, K. Kakihara, S. Ohsawa, T. Oogoe, T. Sugimura, T. T. Takatomi, S. Yamaguchi, K. Yokoyama
    KEK, Ibaraki
  • Y. Hozumi
    GUAS/AS, Ibaraki
  For future energy upgrade of the KEKB injector linac, C-band accelerating section has been developed. First prototype 1-m long section has been installed in the linac and has achieved the accelerating field gradient of 42 MV/m. Developments of second prototype which has thicker coupler iris and third prototype which has smooth surface of the iris are in progress for less frequent breakdown. This paper reports on the recent R and D status of these C-band accelerating sections.  
 
TPPT015 Coupler Matching Techniques for C-Band Accelerating Section target, resonance, coupling, simulation 1431
 
  • K. Yokoyama, M. Ikeda, K. Kakihara, T. Kamitani, S. Ohsawa, T. Sugimura, T. T. Takatomi
    KEK, Ibaraki
  Research and development of the c-band accelerating section has proceeded since 2002. This paper reports the development of the second prototype accelerating section. The coupler iris with a 4 mm thick is thicker than the first prototype because of preventing the rf breakdown at the iris edge. The coupler has a single port and the coupler cell is the same length as the waveguide(WR-187). The coupler cavity diameter and the coupling iris were optimized by using the iteration of the rf measurement which is the nordal shift method.  
 
TPPT020 30 GHz Power Production in CTF3 beam-losses, vacuum, dipole, beam-loading 1695
 
  • W. Wuensch, C. Achard, H.-H. Braun, G. Carron, R. Corsini, A. Grudiev, S.T. Heikkinen, D. Schulte, J.P.H. Sladen, I. Syratchev, F. Tecker, I. Wilson
    CERN, Geneva
  One of the major objectives of CTF3 (CLIC Test Facility) is the production of 30 GHz power for the high-gradient testing of CLIC accelerating structures. To this end a dedicated beam line, power generating structure and power transfer line have been designed, installed and commissioned. 52 MW of 30 GHz power with a pulse length of 74 ns and a repetition rate of 16 Hz were delivered to the high-gradient test area. This will allow operation of test accelerating structures in the coming run of CTF3 up to the nominal CLIC accelerating gradient of 150 MV/m and beyond the nominal pulse length. The system is described and the performances of the CTF3 linac, beam line and the rf components are reviewed.  
 
TPPT021 Characterization and Tuning of a Microwave Gun Cavity gun, coupling, cathode, electron 1748
 
  • W.K. Lau, J. Chan, L.-H. Chang, C.W. Chen, H.Y. Chen, K.-T. Hsu, S.Y. Hsu, J.-Y. Hwang, Y.C. Wang, T.-T. Yang
    NSRRC, Hsinchu
  The SSRL rf gun cavity is electromagnetic structure with a half-cell at the cathode end and a full cell at the other end. Instead of coupling through beam pipe to produce the desired pi-mode for beam acceleration, these two cells are coupled through a frequency tunable side-coupled cell. Therefore, the strucuture is actually 3-cell cavity and the pi/2-mode will be used. This paper reports the characterization of these resonant modes at various side-coupled cell tuning conditions. And the behavior of this cavity will also be analytically examined.  
 
TPPT031 Coupler Design for the LCLS Injector S-Band Structures quadrupole, dipole, emittance, multipole 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, emittance, quadrupole, cathode 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.

 
 
TPPT037 A Coaxial Subharmonic Cavity Design for Direct Injection at the Advanced Photon Source booster, electron, injection, higher-order-mode 2497
 
  • G.J. Waldschmidt, A. Nassiri
    ANL, Argonne, Illinois
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Coaxial subharmonic cavity designs are being investigated at the Advanced Photon Source to improve injector reliability by injecting beam directly from the linac to the booster in storage ring top-up mode. The subharmonic system must operate jointly with the present 352-MHz booster to accelerate the beam to 7 GeV with minimal beam degradation. Design considerations must be made to ensure that bunch purity is maintained and that a large percentage of the linac macropulse is captured. An analysis of rf cavity designs using electromagnetic simulation software has been conducted at 58 MHz and 117 MHz. The final design evaluates the total power loss, field uniformity, and peak surface fields to achieve the required gap voltage.

 
 
TPPT038 Development of C-Band Accelerator Structure with Smooth Shape Couplers simulation, target, positron, acceleration 2530
 
  • T. Sugimura, M. Ikeda, K. Kakihara, T. Kamitani, S. Ohsawa, T. T. Takatomi, K. Yokoyama
    KEK, Ibaraki
  The first C-band accelerator structure for the SuperKEKB injector linac has been operated in the beam line of e+/e- injector linac for KEKB/PF/PF-AR since September, 2003. A new accelerator structure will locate upstream of the first structure. The upstream structure is exposed to higher RF field than that of downstream structure. For the case of first structure, most of an RF breakdown occurs in an input coupler. In order to reduce a frequency of the breakdown, improvement of a coupler is required. In order to suppress a thermionic emission around the coupler iris, thick and smooth iris is adopted for the upstream structure. The development status of this type of upstream structure is described.  
 
TPPT039 Installation and Testing for Commissioning of Normal Conducting RF Linac Segment in the SNS SNS, rfq, resonance, klystron 2571
 
  • Y.W. Kang, A.V. Aleksandrov, D.E. Anderson, M.M. Champion, M. Champion, M.T. Crofford, C. Deibele, G.W. Dodson, R.E. Fuja, P.E. Gibson, P.A. Gurd, T.W. Hardek, G.A. Johnson, P. Ladd, H. Ma, M.P. McCarthy, M.F. Piller, J.Y. Tang, A.V. Vassioutchenko, D.C. Williams
    ORNL, Oak Ridge, Tennessee
  • J.A. Billen, J.T. Bradley, D. Rees, W. Roybal, J. Stovall, K.A. Young, L.M. Young
    LANL, Los Alamos, New Mexico
  The Spallation Neutron Source (SNS) linac employs both normal conducting and superconducting linac cavities that will inject a 1.0 GeV proton beam into its accumulator ring. The normal conducting segment of this linac accelerates the beam to 185 MeV and employs one RFQ and six DTL cavities powered by seven 2.5 MW, 402.5 MHz klystrons and four CCL modules powered by four 5.0 MW, 805 MHz klystrons. Installation and RF conditioning of the RF equipment for normal conducting linac segment have been completed at ORNL with the support of LANL experts. After conditioning the accelerating structures, the linac has been successfully commissioned with beam. This paper reviews the experience in installation, RF conditioning, and commissioning of the normal conducting linac accelerating structures and RF subsystems. Checkout and operation of the RF systems and structures including conditioning procedure establishment and test results compared to the RF design specifications will be discussed.

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.

 
 
TPPT041 RF Tuning and Fabrication Status of the First Module for J-PARC ACS coupling, pick-up, factory, vacuum 2684
 
  • H. Ao, T. Morishita, A. Ueno
    JAERI/LINAC, Ibaraki-ken
  • K. Hasegawa
    JAERI, Ibaraki-ken
  • M. Ikegami
    KEK, Ibaraki
  • V.V. Paramonov
    RAS/INR, Moscow
  • Y. Yamazaki
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  J-PARC Linac starts with 180-MeV SDTL temporary, and it is upgraded to 400-MeV with 21 ACS (Annular Coupled Structure) modules and two ACS bunchers and two debunchers. First buncher module is under fabrication, and second buncher and a few accelerating modules are also planed until FY2006. The first ACS module consists of two 5-cells ACS tanks and a 5-cells bridge cavity for the buncher module. Three RF tuners are installed to the bridge cavity for fine RF tuning. An operating frequency should be tuned to 972 MHz within the fine-tuning range before a brazing process in a factory. The tuning procedure has been studied with RF simulation analysis and cold-model measurements for ACS and bridge cells. This paper describes RF tuning results, fabrication status and related development items.  
 
TPPT044 Beam Position Monitoring Using the HOM-Signals from a Damped and Detuned Accelerating Structure linear-collider, collider, alignment, dipole 2804
 
  • S. Doebert, C. Adolphsen, R.M. Jones, J.R. Lewandowski, Z. Li, M.T.F. Pivi, J.W. Wang
    SLAC, Menlo Park, California
  • T. Higo
    KEK, Ibaraki
  Funding: Work Supported by DOE Contract DE-AC02-76F00515.

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

 
 
TPPT053 Low-Beta SC Quarter-Wave Resonator and Cryomodule for SPIRAL 2 alignment, vacuum, simulation, injection 3238
 
  • S. Chel, P.-E. Bernaudin, P. Bosland, G. Devanz, P. Hardy, F. Michel, A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  In the framework of the SPIRAL 2 project to be built in GANIL, we studied a complete cryomodule for the low beta (0.07) superconducting linac. The 88 MHz quarter wave resonators were optimised for RF, mechanical and thermal considerations. A prototype resonator, which differs from the final resonator by the Helium tank and the removable end-plate geometry and material, has been built. We present the equipments developped for the preparation of this prototype as well as the results of the RF tests. We also detail the mechanical calculation and measurements of the tuning system, and the main aspects of the cryomodule designed to save longitudinal space.  
 
TPPT054 CW Operation of the TTF-III Input Coupler vacuum, klystron, simulation, beam-loading 3292
 
  • J. Knobloch, W. Anders, M. Martin
    BESSY GmbH, Berlin
  • S. Bauer, M. Pekeler
    ACCEL, Bergisch Gladbach
  • S.A. Belomestnykh
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • A. Buechner, H. Buettig, F.G. Gabriel
    FZR, Dresden
  • D. Kostin, W.-D. Müller
    DESY, Hamburg
  Many newly proposed light sources, operating in the CW regime, are based on superconducting TESLA technology. Since this was originally developed for pulsed, 1-% duty-factor operation, it is important to determine the limitations of the TESLA cryomodule and its components when operated CW. Among the critical components is the RF input coupler. Two tests have been performed to determine the average power limit of the TTF-III system. First, room temperature tests up to 4 kW were performed at the Forschungszentrum Rossendorf. These permitted the calibration of computer codes developed to calculate the temperature distribution in the coupler. The programs then were used to make predictions for the (normal) cold operation of the coupler. At BESSY, the coupler test stand was assembled inside the HoBiCaT horizontal cryostat test facility to operate the coupler in an environment close to that of a real accelerator. The results of the two tests are presented here.  
 
TPPT055 Electro-Polishing Surface Preparation for High Gradient Cavities at DESY acceleration, superconductivity, radio-frequency, feedback 3304
 
  • A. Matheisen, h. Morales Zimmermann, B. Petersen, ms. Schmoekel, N. Steinhau-Kuehl
    DESY, Hamburg
  Improvement of acceleration gradients in super conducting accelerator structures was reached by applying electro polishing of the niobium surfaces. This technology is actually foreseen to serve as major surface preparation step for projects like the XFEL at DESY and the proposed ILC linear accelerator. At DESY an electro polishing apparatus was build up in 2003. After commissioning the apparatus operates regular for cavity surface treatment. We report on experiences with the electro-polishing set up, polishing parameters and results on the preparation of S.C. resonators for a high gradient module to be tested in the TTF2 accelerator at DESY.  
 
TPPT056 Design of a Low Loss SRF Cavity for the ILC damping, dipole, linear-collider, collider 3342
 
  • J.S. Sekutowicz
    DESY, Hamburg
  • L. Ge, K. Ko, L. Lee, Z. Li, C.-K. Ng, G.L. Schussman, L. Xiao
    SLAC, Menlo Park, California
  • I.G. Gonin, T.K. Khabiboulline, N. Solyak
    Fermilab, Batavia, Illinois
  • P. Kneisel
    Jefferson Lab, Newport News, Virginia
  • Y. Morozumi, K. Saito
    KEK, Ibaraki
  An international team comprising DESY, KEK, JLAB, FNAL and SLAC is collaborating on the design, fabrication and test of a low loss, 1.3 GHz 9-cell SRF structure as a potential improvement for the ILC main linac. The advantages of this structure over the TTF structure include lower cryogenic loss, shorter rise time, and less stored energy. Among the issues to be addressed in this design are HOM damping, Lorentz force detuning and multipacting. We will report on HOM damping calculations using the parallel finite element eigenmode solver Omega3P and the progress made towards an optimized design. Studies on multipacting and estimates of the Lorentz force detuning will also be presented.  
 
TPPT059 Improvement of the Blade Tuner Design for Superconducting RF Cavities linear-collider, collider, superconducting-RF, proton 3456
 
  • C. Pagani, A. Bosotti, P. Michelato, N. Panzeri, P. Pierini
    INFN/LASA, Segrate (MI)
  Funding: This work is partially supported by the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).

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

 
 
TPPT061 Prototyping of a 352 MHz, beta=0.17 Superconducting Coaxial Half Wave Resonator proton, ion, heavy-ion, vacuum 3547
 
  • A. Facco, F. Scarpa, D. Zenere
    INFN/LNL, Legnaro, Padova
  • V. Zviagintsev
    TRIUMF, Vancouver
  We have designed a 352 MHz superconducting coaxial half wave resonator with beta=0.17. The cavity has a mechanical design similar to the LNL beta=0.31 one developed in 2004. It is very compact (232 mm real-estate length) and it is equipped with a side tuner not exposed to liquid helium, to make it insensitive to pressure fluctuations. Operation is foreseen at 4.2 K. The beta=0.17 cavity fills the gap from 5 to ~25 MeV between the LNL proton RFQ, under construction, and and the existing beta=0.31 half wave resonator. This allows a 5100 MeV proton linac working at 352 MHz with 2 types of coaxial HWR cavities with large velocity acceptance, thus able to accelerate also other ion species (e.g. deuterons). A similar scheme was previously proposed for Spoke resonators; the aim of the HWR choice is compactness and cost reduction. The beta=0.17 cavity is presently under construction in the SPES R&D program at LNL; first test results are expected by the end of 2005.  
 
TPPT062 High Power Test of the Prototype Cryomodule for ADS Superconducting Linac target, klystron, radiation, feedback 3579
 
  • E. Kako, S. Noguchi, N. Ohuchi, T. Shishido, K. Tsuchiya
    KEK, Ibaraki
  • N. Akaoka, H. Kobayashi, N. Ouchi
    JAERI/LINAC, Ibaraki-ken
  • E. Chishiro, T. Hori, M. Nakata, M. Yamazaki
    JAERI, Ibaraki-ken
  A prototype cryomodule containing two 9-cell superconducting cavities of beta=0.725 and fo=972MHz had been constructed under the collaboration of Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK) on the development of superconducting LINAC for Accelerator Driven System (ADS). Cool-down tests to 2.0K of the cryomodule and high power tests with a 972MHz pulsed klystron have been successfully carried out. Rf power of 350kW in a pulsed operation of 3msec and 25Hz was transferred to the nine-cell cavity through an input coupler. Accelerating gradients of about 14MV/m higher than the specification (10MV/m) were achieved in both cavities. Design and performance of the prototype cryomodule and the test results with high rf power will be reported.  
 
TPPT063 Higher-Order-Mode Damping of L-Band Superconducting Cavity using a Radial-Line HOM Damper damping, simulation, dipole, quadrupole 3606
 
  • K. Umemori, M. Izawa, K. Saito, S. Sakanaka
    KEK, Ibaraki
  For the energy recovery linacs, strong damping of higher-order-modes (HOMs) is indispensable to avoid beam breakup instabilities. We studied a new HOM damping scheme using a radial-line HOM damper with a choke structure. Both models of the radial-line damper and the TESLA-type 9-cell cavity were prepared and the HOM characteristics of this scheme were experimentally investigated. Measurement results showed a promising performance of the radial-line HOM damper.  
 
TPPT067 High Power Coupler Studies for the ERLP vacuum, coupling, simulation, booster 3736
 
  • J.H.P. Rogers, C.D. Beard, P.A. Corlett
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Funding: ASTeC, CCLRC Daresbury Laboratory.

Two Superconducting RF modules of the ELBE type have been ordered from Accel Instruments GmbH for use on the Energy Recovery Linac Prototype (ERLP) being built at Daresbury Laboratory. One structure is to be used as a booster module, with an energy gain of 8 MeV, and the other is to act as an energy recovery linac operating at electron beam energy of up to 35 MeV. High power couplers capable of handling up to 10 kW CW are required to provide successful operation of the ERLP. Once received from Accel four couplers including RF windows will be conditioned and tested at FZR Dresden; this paper describes the test procedure anticipated.

 
 
TPPT075 Influence of Ta Content in High Purity Niobium on Cavity Performance vacuum, coupling, electron, SNS 3955
 
  • P. Kneisel, G. Ciovati, G. Myneni
    Jefferson Lab, Newport News, Virginia
  • T. Carneiro
    Reference Metals, Bridgeville, Pennsylvania
  • D. Proch, W. Singer, X. Singer
    DESY, Hamburg
  Funding: Work supported by the U.S. DOE Contract No DE-AC05-84ER40150.

In a previous paper* we have reported about initial tests of single cell 1500 MHz cavities made from high purity niobium with three different Ta contents of 160 ppm, ~600 ppm and ~1400 ppm. These cavities had been treated by buffered chemical polishing several times and 100 mm, 200 mm and 300 mm of material had been removed from the surfaces. This contribution reports about subsequent tests following post purification heat treatments with Ti and “in situ” baking. As a result, all cavities exhibited increased quench fields due to the improved thermal conductivity after the heat treatment. After the "in situ" baking at 120C for ~40 hrs the always present Q-drop at high fields disappeared and further improvements in accelerating gradient could be realized. Gradients as high as Eacc = 35 MV/m were achieved and there were no clear indications that the cavity performance was influenced by the Ta content in the material. A multi-cell cavity from the high Ta content material is being fabricated and results will be presented at this conference.

*P. Kneisel et al., Linac 2004.

 
 
TPPT079 Performance Overview of the Production Superconducting RF Cavities for the Spallation Neutron Source Linac SNS, proton, insertion, controls 4048
 
  • J.P. Ozelis, J.R. Delayen, J. Mammosser
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by U.S. Department of Energy under contract DE-AC05-84ER40150.

As part of its efforts for the SNS construction project, Jefferson Lab has produced 23 cryomodules for the superconducting linac. These modules contained 81 industrially produced multicell Nb accelerating cavities. Each of these cavities was individually tested before assembly into a cryomodule to verify that they achieved the required performance. This ensemble of cavities represents the 3rd largest set of production superconducting cavities fabricated and tested to date. The timely qualification testing of such a collection of cavities offers both challenges and opportunities. Their performance can be characterized by achieved gradient at the required Qo, achieved peak surface field, onset of field emission, and observations of multipacting. Possible correlations between cavity performance and process parameters, only really meaningful in the framework of a large scale production effort, will also be presented. In light of the potential adoption of these cavities for projects such as the Rare Isotope Accelerator or Fermilab Proton Driver, such an analysis is crucial to their success.

 
 
TPPT090 Progress of 2-Cell Cavity Fabrication for Cornell ERL Injector emittance, vacuum, 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 emittance, 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.

 
 
TPPT096 Cryomodule Design for a Superconducting Linac with Quarter-Wave, Half-Wave, and Focusing Elements quadrupole, vacuum, alignment, focusing 4317
 
  • M. J. Johnson, J. Bierwagen, S. Bricker, C. Compton, P. Glennon, T.L. Grimm, W. Hartung, D. Harvell, A. Moblo, J. Popielarski, L. Saxton, R.C. York, A. Zeller
    NSCL, East Lansing, Michigan
  The low-energy section of the driver linac for the proposed Rare Isotope Accelerator (RIA) incorporates the following superconducting elements: quarter-wave resonators, half-wave resonators, and 9 T solenoids. A prototype cryomodule has been designed to house all of these elements. A 31 T/m superferric quadrupole is also included as an alternative focusing element, since its stray magnetic field is more easily shielded. The cryomodule design is based on the RIA v/c=0.47 prototype cryomodule that was successfully tested in 2004.* The design uses a titanium rail structure to support the beam line elements. The beam line assembly is done in a class 100 clean room to maintain resonator cleanliness for optimal high-field performance. The cavities will be equipped with RF input couplers, tuners, and magnetic shields. High Tc current leads are used for both magnets. The cryomodule design takes into account static heat leak requirements and alignment tolerances for the beam line elements. A heat exchanger and J-T throttle valve will be used to provide a continuous supply of liquid helium for 2 K operation.

*T.L. Grimm et al., "Experimental Study of an 805 MHz Cryomodule for the Rare Isotope Accelerator", in Proceedings of the XXII International Linear Accelerator Conference, Lubeck, Germany (2004).

 
 
TPPT099 Prototype Superconducting Triple-Spoke Cavity for Beta = 0.63 vacuum, superconductivity, coupling, electron 4338
 
  • K.W. Shepard, Z.A. Conway, J.D. Fuerst, M. Kedzie, M.P. Kelly
    ANL, Argonne, Illinois
  Funding: This work was supported by the U.S. Department of Energy under contract no. W-31109ENG_38.

This paper reports the development status of a 345 MHz, three-spoke-loaded, TEM-class superconducting cavity with a transit-time factor peaked at beta = v/c = 0.62. The cavity has a 4 cm diameter beam aperture, a transverse diameter of 45.8 cm, and an effective (interior) length of 85 cm. The cavity is the second of two three-spoke loaded cavities being developed for the RIA driver linac and other high-intensity ion linac applications. Construction of a prototype niobium cavity has been completed and the cavity has been chemically processed. Results of initial cold tests will be discussed

 
 
TPPT100 Superconducting Triple-Spoke Cavity for Beta = 0.5 Ions coupling, ion, superconductivity, vacuum 4344
 
  • K.W. Shepard, Z.A. Conway, J.D. Fuerst, M. Kedzie, M.P. Kelly
    ANL, Argonne, Illinois
  Funding: This work was supported by the U.S. Department of Energy under contract no. W-31-109-ENG-38.

This paper reports results of cold tests of a 345 MHz, three-spoke-loaded TEM-class superconducting niobium cavity being developed for the RIA driver linac and for other high-intensity ion linac applications. The cavity has a beam aperture of 4 cm diameter, an interior length of 67 cm, and the transit-time factor peaks at beta = v/c = 0.5. In tests at 4.2 K, the cavity could be operated cw above the nominal design accelerating gradient of 9.3 MV/m, which corresponds to peak surface fields of 27.5 MV/m electric and 826 gauss magnetic. At this gradient the cavity provides more than 6 MV of accelerating potential. The cavity Q at 9.3 MV/m exceeded the nominal performance goal of 7.3E8. Operation at the design gradient at 4.2 K causes substantial boiling and two-phase flow in the liquid helium coolant, with the potential for microphonic-induced fluctuations of the rf frequency. Total microphonic eigenfrequency fluctuations were measured to be less than 1 Hz RMS in cw operation at 9.7 MV/m at 4.2 K.

 
 
TOPA009 Photonic Band Gap Accelerator Demonstration at Ku-Band. electron, klystron, lattice, acceleration 656
 
  • E.I. Smirnova, L.M. Earley, R.L. Edwards
    LANL, Los Alamos, New Mexico
  • A.S. Kesar, I. Mastovsky, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts
  Funding: The research is supported by DOE High Energy Physics, Contract No. DE-FG02-91ER40648.

We report progress on the design and cold test of a metal Ku-band PBG accelerator structure. The 17.140 GHz 6-cell PBG accelerator structure with reduced long-range wakefields was designed for the experiment. The copper structure was electroformed and cold-tested. Tuning was performed through chemical etching of the rods. Final cold test measurements were found to be in very good agreement with the design. The structure will be installed on the beam line at the accelerator laboratory at Massachusetts Institute of Technology and will be powered with 3 MW of peak power from the Haimson 17.14 GHz klystron. Results of the design, fabrication, cold test and hot test on the Haimson accelerator will be presented.

 
 
TOPE001 Experience with the TTF-2 electron, beam-transport, quadrupole, undulator 1
 
  • L. Lilje
    DESY, Hamburg
  The TESLA Test Facility in its second phase (TTF-2) serves two main purposes: It is a testbed for the superconducting RF technology for the International Linear Collider as well as a user facility providing a VUV-FEL beam for experiments using synchrotron light. The presentation will review the progress on the superconducting RF technology. This includes tests on individual cavities as well as full accelerating modules. First experiences with the setup of TTF-2 will be presented. Among others, the measurements of higher order modes in the superconducting cavities are presented. Measurements of the beam properties will be shown.  
 
TOPE002 Advances in Normal Conducting Accelerator Technology from the X-Band Linear Collider Program collider, linear-collider, klystron, gun 204
 
  • C. Adolphsen
    SLAC, Menlo Park, California
  In the early 1990's, groups at SLAC and KEK began dedicated development of X-band (11.4 GHz) rf technology for a next generation, TeV-scale linear collider. The choice of a relatively high frequency, four times that of the SLAC 50 GeV Linac, was motivated by the cost benefits of having lower rf energy per pulse (hence fewer rf components) and reasonable efficiencies at high gradients (hence shorter linacs). However, to realize such savings requires operation at gradients and peak powers much higher than that hitherto achieved. During the past 15 years, these challenges were met through innovations on several fronts, and resulted in a viable rf system design for a linear collider. This paper reviews these achievements, which include developments in the generation and transport of high power rf, and new insights into high gradient limitations.  
 
TOPE004 CLIC Progress Towards Multi-TeV Linear Colliders luminosity, damping, collider, emittance 353
 
  • H.-H. Braun
    CERN, Geneva
  Novel parameters of an e+/e- Linear Collider based on CLIC technology with a broad colliding energy range from 0.5 to 5 TeV are presented for an optimised luminosity of 8x1034 cm-2s-1 at the nominal energy of 3 TeV. They are derived in part from the very successful tests and experience accumulated in the CLIC Test facility, CTF2. A new and ambitious test facility, CTF3, presently under construction at CERN within an international collaboration of laboratories and institutes, and aimed at demonstrating the key feasibility issues of the CLIC scheme, is described.  
 
TOPD001 SC Cyclotron and RIB Facilities in Kolkata cyclotron, ion, target, rfq 89
 
  • B. Sinha, R.K. Bhandari, A. Chakrabarti
    DAE/VECC, Calcutta
  The superconducting cyclotron under construction at this Centre has bending limit (K-bend) of 520 and focusing limit (K-foc) of 160. It is being constructed, primarily, for nuclear physics experiments with heavy ion beams at intermediate energies. The 100-ton main magnet is currently in the commissioning phase with the main coil already at 4.2K temperature. Magnetic field measurements will be carried out over the next several months. All other systems of the cyclotron are in an advanced stage of fabrication or development. We plan to start assembly of the complete cyclotron around the end of 2005. In the phase-I of the project one beam line has been provided. Construction of three more beam lines and various experimental facilities for nuclear physics as well as irradiation experiments has also been funded and the work is well on its way. An ISOL type Radioactive Ion Beam (RIB) facility is being built with the existing K=130 room temperature cyclotron, VEC, as the primary beam source. In-beam RIB production as well as release measurements have been initiated using the VEC beam. The two-ion-source charge breeder consists of a surface ion source and a 6.4 GHz ECR source. The latter has been commissioned. A low beta RFQ to accelerate RIBs to 86 keV/u energy is being fabricated and the cold model tests completed. Design of first three linac tanks, for acceleration up to 400 keV/u, has been finalized and cold model for the first tank has been fabricated. In this talk status of both the projects will be presented.  
 
TOPD002 BEPCII -The Second Phase Construction of the Beijing Electron-Positron Collider luminosity, positron, electron, vacuum 131
 
  • C. Zhang, G. Pei
    IHEP Beijing, Beijing
  The Beijing Electron-Positron Collider (BEPC) was constructed for both high energy physics and synchrotron radiation researches. The peak luminosity of the BEPC has reached its design goal of 5*1030 cm-2s-1 at J/sai energy of 1.55 GeV and 1*1031 cm-2s-1 at 2 GeV respectively. As the second phase construction of the BEPC, the BEPCII has been approved with total budget of 640 million RMB. The construction was started in the beginning of 2004 and is scheduled to be completed by the end of 2007. The BEPCII is a double ring machine with its luminosity goal of 1*1033 cm-2s-1 at 1.89 GeV, two orders of magnitude higher than present BEPC. The upgrading of the collider should also provide an improved SR performance with higher beam energy and intensity. The beam currents will be increased to 250 mA at E=2.5 GeV for the dedicated synchrotron radiation operation of the BEPCII. Some key technologies, such as superconducting RF system, low impedance vacuum devices, superconducting micro-beta quadrupoles and etc., are being developed in order to achieve the target of the BEPCII.*

*Submitted on behalf of the BEPCII Team.

 
 
TOPD004 RIB Facility at VECC Kolkata–A Status Report target, rfq, ion, ion-source 395
 
  • A. Chakrabarti, R.K. Bhandari
    DAE/VECC, Calcutta
  The status of the Radioactive Ion Beam (RIB) facility being built at VECC, Kolkata will be presented. The facility is being built around the existing K=130 cyclotron and will be installed in one of the existing experimental caves. The scheme is to use proton and alpha particles from the cyclotron on a thick production target placed inside an integrated surface ion-source. Radioactive ions with charge state q=1+ extracted from the target-ion-source are to be injected into an on-line ECRIS "charge breeder" for further ionization to q=n+. The 1keV/u, q/A=1/16, RIB of interest will be selected in an isotope separator downstream of the ECRIS and accelerated initially to about 86 keV/u in a Radio Frequency Quadrupole (RFQ) linac and subsequently to about 400 keV/u in three IH-Linac tanks. Since RIB development is R&D intensive, it has been decided to build at first all the basic building blocks and to carry out simultaneously thick target R&D and release measurements using the existing He-jet ISOL facility. Future expansion for further upgradation of energy has been planned. The design of the facility and some recent results will be presented.  
 
WOAA001 The International Linear Collider (ILC) Organization and Plans collider, linear-collider, damping, positron 94
 
  • M. Tigner
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  A discussion of the current organization and Central Team functions will be given. A plan for evolution of the organization towards governance by the funding agencies will be presented. The work plan for the first year will be described and today’s ideas of a possible timeline laid out.  
 
WOAA002 Progress and Plans for R&D and the Conceptual Design of the ILC Main Linacs luminosity, klystron, coupling, collider 199
 
  • H. Hayano
    KEK, Ibaraki
  The International Linear Collider Main Linacs are based on superconducting accelerator structures operating at 1.3 GHz. The basis for this design has been developed and tested at DESY and R&D is progressing at many laboratories around the world including DESY, Orsay, KEK, FNAL, SLAC, Cornell, and JLAB. The status of the TESLA-style cavities and rf system will be reviewed and parameters for the ILC linac will be described. The role of the different linac test facilities will discussed and the critical items and R&D program to support a Conceptual Design and Technical Design will be outlined.  
 
WPAE005 Status of the Cryogenic System Commissioning at SNS SNS, vacuum, Spallation-Neutron-Source, monitoring 970
 
  • F. Casagrande, I.E. Campisi, P.A. Gurd, D.R. Hatfield, M.P. Howell, D. Stout, W.H. Strong
    ORNL, Oak Ridge, Tennessee
  • D. Arenius, J.C. Creel, K. Dixon, V. Ganni, P.K. Knudsen
    Jefferson Lab, Newport News, Virginia
  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 (SNS) is under construction at Oak Ridge National Laboratory. The cold section of the Linac consists of 81 superconducting radio frequency cavities cooled to 2.1K by a 2400 Watt cryogenic refrigeration system. The major cryogenic system components include warm helium compressors with associated oil removal and gas management, 4.5K cold box, 7000L liquid helium dewar, 2.1K cold box (consisting of 4 stages of cold compressors), gaseous helium storage, helium purification and gas impurity monitoring system, liquid nitrogen storage and the cryogenic distribution transfer line system. The overall system commissioning strategy and status will be presented.

 
 
WPAE014 Conceptual Design of a Longitudinal Halo Collimator for J-PARC Linac collimation, emittance, 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.  
 
WPAE025 Design for a 1.3 MW, 13 MeV Beam Dump for an Energy Recovery Linac vacuum, electron, injection, synchrotron 1877
 
  • C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  • Y. He, C.H. Smith
    Cornell University, Ithaca, New York
  Funding: Work supported by Cornell University.

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

 
 
WPAE036 Harmonic Analysis of Linac Alignment alignment, focusing, lattice, laser 2431
 
  • R.C. McCrady
    LANL, Los Alamos, New Mexico
  Funding: Work conducted at Los Alamos National Laboratory, which is operated by the University of California for the United States Department of Energy under contract W-7405-ENG-36.

We have analyzed the requirements on alignment of the focusing elements (quadrupole doublets) in the Los Alamos Neutron Science Center (LANSCE) side coupled linac. The analysis is performed in terms of harmonics of the quardrupole spacing. This allows us to determine the effect of intentional deviations from a straight line, such as following the curvature of the Earth, and of unintentional deviations introduced by measurement and alignment errors. Results are compared to measured positions of the doublets.

 
 
WPAE038 Resonance Control Cooling System Performance and Developments resonance, SNS, simulation, Spallation-Neutron-Source 2541
 
  • P.E. Gibson, A.V. Aleksandrov, M.M. Champion, G.W. Dodson, J.P. Schubert, J.Y. Tang
    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 (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. The warm linac portion, designed by Los Alamos, has been installed and commissioned. The warm linac is comprised of six Drift Tube Linac (DTL) tanks and four Coupled Cavity Linac (CCL) modules. For commissioning purposes the accelerating systems have been operated at less than the design 6% duty factor. During lower power operation there is less RF cavity heating. This decrease in heat load causes operational stability issues for the associated Resonance Control Cooling Systems (RCCSs) which were designed for full duty factor operation. To understand this effect operational results have been analyzed and tests have been performed. External system factors have been explored and the resulting impacts defined. Dynamic modeling of the systems has been done via a collaboration with the Institute for Nuclear Research (INR), Moscow, Russia. New RCCS operation code has been implemented. Increases in system performance achieved and solutions employed will be presented.

 
 
WPAE040 Comparison of Techniques for Longitudinal Tuning of the SNS Drift Tube Linac simulation, SNS, Spallation-Neutron-Source, target 2616
 
  • D.-O. Jeon
    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 important to bring the cavity field amplitude and phase to the design values for a high intensity linac such as the Spallation Neutron Source (SNS)linac. A few techniques are available, such as the longitudinal acceptance scan and phase scan. During SNS linac commissioning, tuning of cavities was conducted using the acceptance scan and phase scan technique based on multiparticle simulations. The two techniques are compared.

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

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

 
 
WPAE044 An Alignment of J-PARC Linac alignment, target, synchrotron, survey 2851
 
  • T. Morishita, H. Ao, T. Ito, A. Ueno
    JAERI/LINAC, Ibaraki-ken
  • K. Hasegawa
    JAERI, Ibaraki-ken
  • M. Ikegami, C. Kubota, F. Naito, E. Takasaki, H. Tanaka, K. Yoshino
    KEK, Ibaraki
  J-PARC linear accelerator components are now being installed in the accelerator tunnel, whose total length is more than 400 m including the beam transport line to RCS (Rapid Cycling Synchrotron). A precise alignment of accelerator components is essential for a high quality beam acceleration. In this paper, planned alignment schemes for the installation of linac components, the fine alignment before beam acceleration, and watching the long term motion of the building are described. Guide points are placed on the floor, which acts as a reference for the initial alignment at the installation and also as a relay point for the long surveying network linking at the fine alignment. For a straight line alignment, the wire position sensor is placed on the offset position with respect to the beam center by a target holder, then a single wire can cover the accelerator cavities and the focusing magnets at the DTL-SDTL section (120m). The hydrostatic levering system (HLS) is used for watching the floor elevation (changes) over the long period.  
 
WPAE046 Diffusion Brazing and Welding of the Accelerating Structure vacuum, microtron 2938
 
  • V.S. Avagyan
    CANDLE, Yerevan
  Funding: This work has been performed in Yerevan Physics Institute and the Institute of Electrowelding E.O. Paton, the Ukraine.

This work presents technologies of copper accelarating structure diffusion joints. The formation conditions of copper diffusion joint with minimal residual plastic strain are determined experimentally.

 
 
WPAE060 Programmable Power Supply for AC Switching Magnet of Proton Accelerator power-supply, proton, simulation, extraction 3508
 
  • S.-H. Jeong, H.S. Han, Y.G. Jung, H.-S. Kang, H.-G. Lee, K.-H. Park, C. K. Ryu, H.S. Suh
    PAL, Pohang, Kyungbuk
  • H.H. Lee
    UU, Gyeongju
  Funding: Ministry of Science and Technology.

The 100-MeV PEFP proton linac has two proton beam extraction lines for user’ experiment. Each extraction line has 5 beamlines and has 5 Hz operating frequency. An AC switching magnet is used to distribute the proton beam to the 5 beamlines, An AC switching magnet is powered by PWM-controlled bipolar switching-mode converters. This converter is designed to operate at ±350A, 5 Hz programmable step output. The power supply is employed IGBT module and has controlled by a DSP (Digital Signal Process). This paper describes the design and test results of the power supply.

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

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

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

 
 
WPAE072 Installation and Testing of SNS Magnet Power Supplies power-supply, SNS, injection, dipole 3889
 
  • K.R. Rust, W.E. Barnett, R.I. Cutler, J. T. Weaver
    ORNL, Oak Ridge, Tennessee
  • S. Dewan, R. Holmes, S. Wong
    IE Power Inc., Mississauga, Ontario
  • R.F. Lambiase, J. Sandberg
    BNL, Upton, Long Island, New York
  • J. Zeng
    Digital Predictive Systems Inc., Toronto
  Funding: This work was supported by SNS through UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

This paper describes the types and quantities of magnet power supplies required for the SNS Linear Accelerator, High-Energy Beam Transport (HEBT), Ring and the Ring-Target Beam Transport (RTBT). There are over 600 magnets and more than 550 magnet power supplies. These magnet power supplies range in size from the bipolar-corrector supplies rated at 35 volts, 20 amps to the main-ring dipole supply that is rated at 440 volts, 6000 amps. The Linac power supplies have a ripple/stability specification of 1000 parts per million while the ring supplies have a specification of 100 parts per million. There are also pulsed power supplies for beam injection and beam extraction. The paper will show acceptance test results from the manufacturers as well as test results performed by the SNS magnet power supply group.

 
 
WPAP001 HELIOS, the Linac Injector of SOLEIL: Installation and First Results gun, electron, emittance, 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.

 
 
WPAP017 Experimental Observation of a 100-Femtosecond Single Electron Bunch in Photocathode Linac with Longitudinal Emittance Compensation Technique electron, gun, emittance, 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, gun, laser, emittance 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, emittance 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.  
 
WPAP034 Positron Emulator for Commissioning ILC Positron Source positron, electron, target, damping 2321
 
  • H. Wang, W. Gai, K.-J. Kim, W. Liu
    ANL, Argonne, Illinois
  Funding: U.S. DOE.

It is apparent that the gamma-ray based positron source components including positron linac and damping rings for ILC can not be easily commissioned until the electron beam is fully conditioned at high energies (> 150 GeV). In this paper, we discuss a scheme that could use a short and energetic electron beam scattered through a set of carefully selected targets to simulate certain behaviors of the positron beam, such as beam emittance and energy spread. The basic idea is to make the phase space distribution of the scattered electron beam to reflect certain aspects of the positron beam distributions. Subsequently, the positron source elements such as capture optics, linacs and even damping ring could be effectively commissioned before ILC colliding electron beam is ready. The simulation results using EGS4 for beam scattering and PARMELA for beam dynamics are presented.

 
 
WPAP037 Novel Method of Emittance Preservation in ERL Merging System in Presence of Strong Space Charge Forces electron, emittance, space-charge, gun 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.

 
 
WPAP041 Time Dependent Quantum Efficiency and Dark Current Measurements in an RF Photocathode Injector with a High Quantum Efficiency Cathode gun, cathode, electron, laser 2681
 
  • R.P. Fliller, H. Edwards
    Fermilab, Batavia, Illinois
  • W. Hartung
    NSCL, East Lansing, Michigan
  Funding: This work was supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U.S. DOE and by NICADD.

A system was developed at INFN Milano for preparing cesium telluride photo-cathodes and transferring them into an RF gun under ultra-high vacuum. This system has been in use at the Fermilab NICADD Photo-Injector Laboratory (FNPL) since 1997. A similar load-lock system is used at the TeSLA Test Facility at DESY-Hamburg. Two 1.625-cell high duty cycle RF guns have been fabricated for the project. Studies of the photo-emission and field emission ("dark current") behavior of both RF guns have been carried out. Unexpected phenomena were observed in one of the RF guns. In situ changes in the cathode's quantum efficiency and dark current with time were seen during operation of the photo-injector. These changes were correlated with the magnetostatic field at the cathode.* In addition, multipacting is observed in the RF guns under certain conditions. Recent measurements indicate a correlation between multipacting, anomalous photo-emission behavior, and anomalous field emission behavior. Results will be presented.

*W. Hartung, J.-P. Carneiro, H. Edwards, M. Fitch, M. Kuchnir, P. Michelato, D. Sertore, in Proceedings of the 2001 Particle Accelerator Conference, p. 2239-2241.

 
 
WPAP047 Preliminary Results from a Superconducting Photocathode Sample Cavity cathode, gun, vacuum, brightness 2956
 
  • P. Kneisel
    Jefferson Lab, Newport News, Virginia
  • R.S. Lefferts, A.R. Lipski
    SBUNSL, Stony Brook, New York
  • J.S. Sekutowicz
    DESY, Hamburg
  Funding: Work supported by the U.S. DOE Contract No DE-AC05-84ER40150.

Pure niobium has been proposed as a photocathode material and recently a successful test has been conducted with a niobium single cell cavity to extract photo-currents from the surface of this cavity. However, the quantum efficiency of niobium is ~210-4, whereas electrodeposited lead has a ~15 times higher quantum efficiency. We have designed and tested a photo-injector niobium cavity, which can be used to insert photo-cathodes made of different materials in the high electric field region of the cavity. Experiments have been conducted with niobium and lead, which show that neither the Q- values of the cavity nor the obtainable surface fields are significantly lowered. This paper reports about the results from these tests.

 
 
WPAT004 Coupling Methods for Superconducting CH-Cavities coupling, simulation, vacuum 922
 
  • H. Liebermann, H. Podlech, U. Ratzinger, A.C. Sauer
    IAP, Frankfurt-am-Main
  Funding: GSI, BMBF contr. No. 06F134I, EU.

The cross-bar H-type (CH) cavity is a multi-gap drift tube structure based on the H-210 mode currently under development at IAP Frankfurt and in collaboration with GSI. Numerical simulations and rf model measurements showed that the CH-type cavity is an excellent candidate to realize Room Temperature and Superconducting multi-cell structures with a frequency range from about 150 MHz up to 800 MHz. For coupling into such a complex structure, we compare two coupling methods, one with capacitive and the other with inductive couplers. This paper will present detailed MicroWave Studio simulations and measurements for these different coupling methods for Room Temperature and Superconducting CH-Cavities. For coupling into a Superconducting CH-Cavity we prefer a capacitive coupler. We will also present an optimized Superconducting CH-Cavity for capacitive couplers.

 
 
WPAT005 A New Tuning Module for Resonant Coupling Structures coupling, proton, klystron, booster 973
 
  • V.G. Vaccaro
    Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli
  • T. Clauser, A. Rainò, V. Variale
    INFN-Bari, Bari
  • A. D'Elia
    Naples University Federico II and INFN, Napoli
  • C. De Martinis, D. Giove
    INFN-Milano, Milano
  • M.R. Masullo
    INFN-Napoli, Napoli
  • M. Mauri
    INFN/LASA, Segrate (MI)
  In order to have efficient particle acceleration it is fundamental that the particles experience, in the accelerating gap, field amplitudes as uniform and as high as possible from gap to gap. Because of the unavoidable fabrication errors, an accelerating structure, when assembled, exhibits field values lower than the nominal ones and/or not uniform. All the usual procedures developed in order to adjust the parameter deviations responsible of the malfunction of these structures, are based on field amplitude measurements, by using the bead pull technique, which is a very invasive technique. In this paper the philosophy is reversed: it is assumed that all the information can be got by Sounding the Modes of the whole System (SMS) and correct the deviation of each frequency mode from its nominal value by means of an appropriate tuning of the cavities: resorting to a perturbative technique applied to a circuit model representing this kind of structures, it is possible to calculate the amount of tuning to give to the cavities. It will be shown that a very good equalization and maximization of the fields in the cavities can be achieved by using this technique.  
 
WPAT006 The SPARC RF Synchronization System laser, gun, feedback, klystron 1024
 
  • A. Gallo, D. Alesini, M. Bellaveglia, R. Boni, G. Di Pirro, F. Tazzioli
    INFN/LNF, Frascati (Roma)
  The SPARC project consists in a 150 MeV Linac aimed at driving an ondulator for the production of 530 nm SASE FEL radiation. A bunch transverse emittance as low as 1mm mrad and a bunch peak current of about 100 A are required for this task. The RF voltages in the RF gun and in the 3 S-band accelerating sections have to be kept phase locked within 3 ps to the arrival time of the laser pulse on the photocathode to guarantee the required performances. This specification will be reduced to 0.5 ps in the phas·10-2 of the project when the rectilinear RF compression of the bunch will be tested. The general architecture of the SPARC RF control system together with some bench qualification measurements of the basic components is presented in this paper.  
 
WPAT008 Recent Status of RF Source in J-PARC Linac klystron, proton, power-supply, site 1123
 
  • E. Chishiro, T. Hori, H. Suzuki, M. Yamazaki
    JAERI, Ibaraki-ken
  • S. Anami, S. Fukuda, Y. Fukui, M. Kawamura, S. Yamaguchi, M. Yoshida
    KEK, Ibaraki
  The construction of the J-PARC (Japan Proton Accelerator Research Complex) linac is under going. RF sources for the low beta linac section use 324-MHz klystrons and after the evaluation of seven prototype tubes, mass production of 20 tubes are conducted. These will be installed in the linac building from April 2005. Performances of the 324-MHz klystrons are described in this paper. The prototype klystron of 972-MHz klystron, which is planed to be installed in high beta linac section, oscillated strongly without any drive rf power, and it had been investigated to solve it. Though it was doubted to be a diode oscillation at first, recent experiment showed the drift-tube oscillation and we succeeded in stopping oscillation by deforming the integrated cavity and detuning. After this experiment, we built a new tube and started to test it. This experiment is written in this paper. Other status of construction related to the rf sources is also shown in this paper.  
 
WPAT015 The Digital Feedback RF Control System of the RFQ and DTL1 for 100 MeV Proton Linac of PEFP feedback, proton, rfq, resonance 1443
 
  • I.H. Yu, Y.J. Han, H.-S. Kang, D.T. Kim, S.-C. Kim, I.-S. Park, J.C. Yoon
    PAL, Pohang, Kyungbuk
  • Y.-S. Cho, H.-J. Kwon, K.T. Seol
    KAERI, Daejon
  Funding: Work supported by the PEFP (Proton Engineering Frontier Project), Korea

The 100 MeV Proton linear accelerator (Linac) for the PEFP (Proton Engineering Frontier Project) will include 1 RFQ and 1 DTL1 at 350 MHz as well as 7 DTL2 cavities at 700 MHz. The low level RF system with the digital feedback RF control provides the field control to accelerate a 20mA proton beam from 50 keV to 20 MeV with a RFQ and a DTL1 at 350M Hz. The FPGA-based digital feedback RF control system has been built and is used to control cavity field amplitude within ± 1% and relative phase within ± 1°. The fast digital processing is networked to the EPICS-based control system with an embedded processor (Blackfin). In this paper, the detailed description of the digital feedback RF control system will be described with the performance test results.

 
 
WPAT022 Low Level RF System for the Energy Recovery Linac Prototype laser, gun, feedback, pick-up 1781
 
  • A.J. Moss
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Funding: ASTeC Department, CCLRC Daresbury Laboratory.

The Low Level RF system is described for the Energy Recovery Linac Prototype (ERLP) being constructed at Daresbury Laboratory. An analogue based feedback system, built around low cost proprietary components, has been designed to control the 1.3GHz RF system for this project. The system is scaleable, has digital control and can be easily upgraded as greater understanding of the accelerator becomes known. The design of the system is based around the central core of a very low phase noise master oscillator, which can provide, multiple outputs and timing pulses at all the required frequencies for the RF, laser and accelerator sub-systems.

 
 
WPAT029 The RF Experimental Program in the Fermilab MUCOOL Test Area background, electron, target, site 2104
 
  • J. Norem
    ANL, Argonne, Illinois
  • A. Bross, A. Moretti, Z. Qian
    Fermilab, Batavia, Illinois
  • R.P. Johnson
    Muons, Inc, Batavia
  • D. Li, M.S. Zisman
    LBNL, Berkeley, California
  • R.A. Rimmer
    Jefferson Lab, Newport News, Virginia
  • R. Sandstrom
    CUI, Geneva
  • Y. Torun
    IIT, Chicago, Illinois
  Funding: DOE

The rf R&D program for high gradient, low frequency cavities to be used in muon cooling systems is underway in the Fermilab Muon Test Area. Cavities at 805 and 201 MHz are used for tests of conditioning techniques, surface modification and breakdown studies. This work has the Muon Ionization Cooling Experiment (MICE) as its immediate goal and efficient muon cooling systems for neutrino sources and muon colliders as the long term goal. We study breakdown, and dark current productions under a variety of conditions.

 
 
WPAT030 Upgrade of the ATLAS Positive Ion Injector Bunching System feedback, ion, pick-up, bunching 2161
 
  • S.I. Sharamentov, M. Bogaty, E. Clifft, R.C. Pardo
    ANL, Argonne, Illinois
  Over the last few years, significant efforts were concentrated on improving the ATLAS Positive Ion Injector (PII) RF bunching system, consisting of a four-harmonic pre-buncher, Traveling Wave Chopper (TWC) and a single-frequency sinusoidal re-buncher. The primary goal was to improve RF field stability with a redesigned RF system and to improve buncher performance for higher current beams resulting in better bunch stability and time structure at the first PII superconducting resonator. The major parts of the system were redesigned and rebuilt, including the RF 12 – 48 MHz amplifiers for the harmonic pre-buncher and re-buncher, RF driver rack for the TWC, and the RF control chassis for both the pre-buncher and re-buncher. The four-harmonic resonant structure of the harmonic buncher itself was modified, too, mainly for better mechanical stability and better RF matching. These improvements will be described and the performance of the new system presented.  
 
WPAT034 The CEBAF Separator Cavity Resonance Control System resonance, controls, monitoring, electron 2339
 
  • M.J. Wissmann, AA. Guerra, C. Hovater, T. Plawski
    Jefferson Lab, Newport News, Virginia
  Funding: This work supported by the U.S. Department of Energy under contract DE-AC05-84ER40150.

The CEBAF energy upgrade from 6 GeV to 12GeV will increase the range of beam energies available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three experimental halls. Consequently with the increase in RF separator cavity gradient needed for the higher energies, RF power will also increase requiring the cavities to have active resonance control. At the 6 GeV energy, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW), which is maintained at constant temperature of 95o Fahrenheit. This is no longer feasible and an active resonance control system, that controls both water temperature and flow has been built. The system uses a commercial PLC with embedded PID controls to control water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately closed loop control will be maintained by monitoring the cavities reflected power. This paper describes this system.

 
 
WPAT037 LANSCE RF System Refurbishment klystron, proton, SNS, diagnostics 2476
 
  • D. Rees, G. Bolme, S.I. Kwon, J.T.M. Lyles, M.T. Lynch, M. Prokop, W. Reass, P.J. Tallerico
    LANL, Los Alamos, New Mexico
  The Los Alamos Neutron Science Center (LANSCE) is in the planning phase of a refurbishment project that will sustain reliable facility operations well into the next decade. The LANSCE accelerator was constructed in the late 1960s and early 1970s and is a national user facility that provides pulsed protons and spallation neutrons for defense and civilian research and applications. We will be replacing all the 201 MHz RF systems and a substantial fraction of the 805 MHz RF systems and high voltage systems. The current 44 LANSCE 805 MHz, 1.25 MW klystrons have an average in-service time in excess of 110,000 hours. All 44 must be in service to operate the accelerator. There are only 9 spares left. The klystrons receive their DC power from the power system originally installed in 1960. Although this power system has been extremely reliable, gas analysis of the insulating oil is indicating age related degradation that will need attention in the next few years. This paper will provide the design details of the new RF and high voltage systems.  
 
WPAT040 Pushing the Limits: RF Field Control at High Loaded Q resonance, beam-loading, klystron, feedback 2642
 
  • M. Liepe, S.A. Belomestnykh, J. Dobbins, R.P.K. Kaplan, C.R. Strohman, B.K. Stuhl
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • C. Hovater, T. Plawski
    Jefferson Lab, Newport News, Virginia
  Funding: This work is supported by Cornell University.

The superconducting cavities in an Energy-Recovery-Linac will be operated with a high loaded Q of several 1E7, possible up to 1E8. Not only has no prior control system ever stabilized the RF field in a linac cavity with such high loaded Q, but also highest field stability in amplitude and phase is required at this high loaded Q. Because of a resulting bandwidth of the cavity of only a few Hz, this presents a significant challenge: the field in the cavity extremely sensitive to any perturbation of the cavity resonance frequency due to microphonics and Lorentz force detuning. To prove that the RF field in a high loaded Q cavity can be stabilized, and that Cornell's newly developed digital control system is able to achieve this, the system was connected to a high loaded Q cavity at the JLab IR-FEL. Excellent cw field stability – about 2·10-4 rms in relative amplitude and 0.03 deg rms in phase - was achieved at a loaded Q of 2.1·107 and 1.4E8, setting a new record in high loaded Q operation of a linac cavity. Piezo tuner based cavity frequency control proved to be very effective in keeping the cavity on resonance and allowed reliable to ramp up to high gradients in less than 1 second.

 
 
WPAT043 Overview of the RF Systems for LCLS gun, feedback, undulator, klystron 2753
 
  • P.A. McIntosh, R. Akre, R.F. Boyce, P. Emma, S. Hill, E. Rago
    SLAC, Menlo Park, California
  Funding: Work supported by Department of Energy contract DE-AC03-76SF00515.

The Linac Coherent Light Source (LCLS) at SLAC, when it becomes operational in 2009, will provide its user community with an X-ray source many orders of magnitude brighter than anything available in the world at that time. The electron beam acceleration will be provided by existing and new RF systems capable of maintaining the amplitude and phase stability of each bunch to extremely tight tolerances. RF feedback control of the various RF systems will be fundamental in ensuring the beam arrives at the LCLS undulator at precisely the required energy and phase. This paper details the requirements for RF stability for the various LCLS RF systems and also highlights proposals for how these injector and Linac RF systems can meet these constraints.

 
 
WPAT044 Realization of an X-Band RF System for LCLS klystron, vacuum, linear-collider, collective-effects 2801
 
  • P.A. McIntosh, R. Akre, J. Brooks, P. Emma, E. Rago
    SLAC, Menlo Park, California
  Funding: Work supported by Department of Energy contract DE-AC03-76SF00515.

A single X-band (11.424 GHz) accelerating structure is to be incorporated in the LCLS Linac design to linearize the energy-time correlation (or gradient) across each bunch, features which originate in the preceding accelerating structures (L0 and L1). This harmonic RF system will operate near the negative RF crest to decelerate the beam, reducing these non-linear components of the correlation, providing a more efficient compression in the downstream bunch compressor chicanes (BC1 and BC2). These non-linear correlation components, if allowed to grow, would lead to Coherent Synchrotron Radiation (CSR) instabilities in the chicanes, effectively destroying the coherence of the photon radiation in the main LCLS undulator. The many years devoted at SLAC in the development of X-band RF components for the NLC/JLC linear collider project, has enabled the technical and financial realization of such an RF system for LCLS. This paper details the requirements for the X-band system and the proposed scheme planned for achieving those requirements.

 
 
WPAT050 High Power Phase Shifter resonance, proton, klystron, power-supply 3123
 
  • I. Terechkine, G.W. Foster, I.G. Gonin, T.K. Khabiboulline, A. Makarov, N. Solyak, D. Wildman
    Fermilab, Batavia, Illinois
  One of the approaches to power distribution system of a superconducting proton linac that is under discussion at Fermilab requires development of a fast-action, megawatt-range phase shifter. Using two phase shifters with a waveguide hybrid junction can allow independent control of phase and amplitude of RF power at the input of each superconducting cavity of the linac. This promises significant saving in number of klystrons and modulators required for the accelerator. A prototype of a waveguide version of a phase shifter that uses Yttrium-Iron Garnet (YIG) blocks was developed and tested. This report presents design concept of the device and main results of simulation and proof-of-principle tests.  
 
WPAT053 Results of a High-Power Klystron Dip Test in the KEK Linac klystron, cathode, injection, space-charge 3235
 
  • K. Nakao, S. Fukuda, H. Katagiri, T. Matsumoto, S. Michizono, T. Takenaka, Y. Yano, M. Yoshida
    KEK, Ibaraki
  Dip test, which is the measurement of a klystron heater activity, is recently adopted as the standard measurement to maintain the klystron operation in the KEK electron-positron linac. In 2003, we began to use a dip test as the quick way to measure the emission characteristics from the klystron cathode. After the successful results, we made the dedicated measuring systems and measured the dips of the cathode emission of 60 operating klystrons in KEK electron-positron linac. These data are important to estimate the klystron cathode life and used to select the candidate klystrons of replacement in the summer maintenance period.  
 
WPAT054 5 MW 805 MHz SNS RF System Experience klystron, vacuum, SNS, shielding 3280
 
  • K.A. Young, J.T. Bradley, T.W. Hardek, M.T. Lynch, D. Rees, W. Roybal, P.J. Tallerico, P.A. Torrez
    LANL, Los Alamos, New Mexico
  Funding: Work supported by the U.S. DOE.

The RF system for the 805 MHz normal conducting linac of the Spallation Nuetron Source (SNS) accelerator was designed, procured and tested at Los Alamos National Laboratory(LANL) and then installed and commissioned at Oak Ridge National Laboratory (ORNL). The RF power for this room temperature coupled cavity linac (CCL) of SNS accelerator is generated by four pulsed 5 MW peak power klystrons operating with a pulse width of 1.25 mSec and a 60 Hz repetition frequency. The RF power from each klystron is divided and delivered to the CCL through two separate RF windows. The 5 MW RF system advanced the state of the art for simultaneous peak and average power. This paper summarizes the problems encountered, lessons learned and results of the high power testing at LANL of the 5 MW klystrons, 5 MW circulators, 5 MW loads, and 2.5 MW windows.*

*Tom Hardek is now at ORNL.

 
 
WPAT055 Enhancements for the 1 MW High Voltage Converter Modulator Systems at the SNS klystron, SNS, cathode, resonance 3313
 
  • D.E. Anderson, J. Hicks, D. E. Hurst, E.R. Tapp, M. Wezensky
    ORNL, Oak Ridge, Tennessee
  • D. Baca, W. Reass
    LANL, Los Alamos, New Mexico
  • V.V. Peplov
    RAS/INR, Moscow
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The first-generation high frequency switching megawatt-class high voltage converter modulators (HVCM) developed by Los Alamos National Laboratory for the Spallation Neutron Source at Oak Ridge National Laboratory have been installed and are now operational. Each unit is capable of delivering pulses up to 11 MW peak, 1 MW average power at voltages up to 140 kV to drive klystron(s) rated up to 5 MW. To date, three variations of the basic design have been installed, each optimized to deliver power to a specific klystron load configuration. Design improvements, with the primary intention of improving system reliability and availability, have been under development since the initial installation of the HVCM units. This paper will examine HVCM reliability studies, reliability operational data, and modifications and improvements performed to increase the overall system availability. We will also discuss system enhancements aimed at improving the ease of operation and providing for additional equipment protection features.

 
 
WPAT057 Overview of the Spallation Neutron Source Linac Low-Level RF Control System SNS, Spallation-Neutron-Source, klystron, feedback 3396
 
  • M. Champion, M.T. Crofford, K.-U. Kasemir, H. Ma, M.F. Piller
    ORNL, Oak Ridge, Tennessee
  • L.R. Doolittle, A. Ratti
    LBNL, Berkeley, California
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The design and production of the Spallation Neutron Source Linac Low-Level RF control system is complete, and installation will be finished in Spring 2005. The warm linac beam commissioning run in Fall 2004 was the most extensive test to date of the LLRF control system, with fourteen (of an eventual 96) systems operating simultaneously. In this paper we present an overview of the LLRF control system, the experience in designing, building and installing the system, and operational results.

 
 
WPAT058 Operational Experience with the Spallation Neutron Source High Power Protection Module SNS, monitoring, klystron, Spallation-Neutron-Source 3411
 
  • M.T. Crofford, M. Champion, K.-U. Kasemir, H. Ma, M.F. Piller
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source (SNS) High Power Protection Module provides protection for the High Power RF Klystron and Distribution System and interfaces with the Low-Level Radio-Frequency (LLRF) Field Control Module (FCM). The fault detection logic is implemented in a single FPGA allowing modifications and upgrades to the logic as we gain operational experience with the LINAC RF systems. This paper describes the integration and upgrade issues we have encountered during the initial operations of the SNS systems.  
 
WPAT059 High Power RF Test Facility at the SNS SNS, klystron, vacuum, monitoring 3450
 
  • Y.W. Kang, D.E. Anderson, I.E. Campisi, M. Champion, M.T. Crofford, R.E. Fuja, P.A. Gurd, S. Hasan, K.-U. Kasemir, M.P. McCarthy, D. Stout, J.Y. Tang, A.V. Vassioutchenko, M. Wezensky
    ORNL, Oak Ridge, Tennessee
  • G.K. Davis, M. A. Drury, T. Powers, M. Stirbet
    Jefferson Lab, Newport News, Virginia
  RF Test Facility has been completed in the SNS project at ORNL to support test and conditioning operation of RF subsystems and components. The system consists of two transmitters for two klystrons powered by a common high voltage pulsed converter modulator that can provide power to two independent RF systems. The waveguides are configured with WR2100 and WR1150 sizes for presently used frequencies: 402.5 MHz and 805 MHz. Both 402.5 MHz and 805 MHz systems have circulator protected klystrons that can be powered by the modulator capable of delivering 11 MW peak and 1 MW average power. The facility has been equipped with computer control for various RF processing and complete dual frequency operation. More than forty 805 MHz fundamental power couplers for the SNS superconducting linac (SCL) cavitites have been RF conditioned in this facility. The facility provides more than 1000 ft2 floor area for various test setups. The facility also has a shielded cave area that can support high power tests of normal conducting and superconducting accelerating cavities and components.

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.

 
 
WPAT060 SNS Low-Level RF Control System: Design and Performance SNS, controls, feedback, damping 3479
 
  • H. Ma, M. Champion, M.T. Crofford, K.-U. Kasemir, M.F. Piller
    ORNL, Oak Ridge, Tennessee
  • L.R. Doolittle, A. Ratti
    LBNL, Berkeley, California
  Funding: ORNL managed by UT-Battelle for US DOE.

A full digital Low-Level RF controller has been developed for SNS LINAC. Its design is a good example of a modern digital implementation of the classic control theory. The digital hardware for all the control and DSP functionalities, including the final vector modulation, is implemented on a single high-density FPGA. Two models for the digital hardware have been written in VHDL and Verilog respectively, based on a very low latency control algorithm, and both have been being used for supporting the testing and commissioning the LINAC to the date. During the commissioning, the flexibility and ability for precise controls that only digital design on a larger FPGA can offer has proved to be a necessity for meeting the great challenge of a high-power pulsed SCL.

 
 
WPAT061 Spallation Neutron Source High Power RF Installation and Commissioning Progress klystron, SNS, rfq, Spallation-Neutron-Source 3520
 
  • M.P. McCarthy, D.E. Anderson, R.E. Fuja, P.A. Gurd, T.W. Hardek, Y.W. Kang
    ORNL, Oak Ridge, Tennessee
  • J.T. Bradley, D. Rees, W. Roybal, K.A. Young
    LANL, Los Alamos, New Mexico
  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) linac will provide a 1 GeV proton beam for injection into the accumulator ring. In the normal conducting (NC) section of this linac, the Radio Frequency Quadupole (RFQ) and six drift tube linac (DTL) tanks are powered by seven 2.5 MW, 402.5 MHz klystrons and the four coupled cavity linac (CCL) cavities are powered by four 5.0 MW, 805 MHz klystrons. Eighty-one 550 kW, 805 MHz klystrons each drive a single cavity in the superconducting (SC) section of the linac. The high power radio frequency (HPRF) equipment was specified and procured by LANL and tested before delivery to ensure a smooth transition from installation to commissioning. Installation of RF equipment to support klystron operation in the 350-meter long klystron gallery started in June 2002. The final klystron was set in place in September 2004. Presently, all RF stations have been installed and high power testing has been completed. This paper reviews the progression of the installation and testing of the HPRF Systems.

 
 
WPAT062 The Spallation Neutron Source RF Reference System SNS, rfq, Spallation-Neutron-Source, klystron 3573
 
  • M.F. Piller, M. Champion, M.T. Crofford, H. Ma
    ORNL, Oak Ridge, Tennessee
  • L.R. Doolittle
    LBNL, Berkeley, California
  The Spallation Neutron Source (SNS) RF Reference System includes the master oscillator (MO), local oscillator(LO) distribution, and Reference RF distribution systems. Coherent low noise Reference RF signals provide the ability to control the phase relationships between the fields in the front-end and linear accelerator (linac) RF cavity structures. The SNS RF Reference System requirements, implementation details, and performance are discussed.  
 
WPAT063 Design and Status of the BPM RF Reference Distribution in the SNS SNS, diagnostics, beam-transport, Spallation-Neutron-Source 3615
 
  • A. Webster, C. Deibele, J. Pogge
    ORNL, Oak Ridge, Tennessee
  • J.F. Power
    LANL, Los Alamos, New Mexico
  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 (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. The BPMs (Beam Position Monitors) requires RF reference signals to measure the phase of the beam with respect to the RF. In the MEBT (Medium Energy Beam Transport) Line and in the DTLs (Drift Tube Linac Cavities) are cavities that accelerate and bunch the beam at 402.5 MHz. In the CCLs (Coupled Cavity Linac) and SCLs (Superconducting Linac) accelerate the beam at 805 MHz. To mitigate effects of RF leakage into the BPM electrodes it is required to measure the phase in the MEBT and DTLs at 805 MHz and in the CCL and SCL at 402.5 MHz. We are directly connected to the RF group MO (master oscillator) and send these signals along the entire linac using fiber optic technology. Schematics, measurements, and installation update are discussed.

 
 
WPAT064 Low Level RF Control System of J-PARC Synchrotrons synchrotron, beam-loading, proton, feedback 3624
 
  • F. Tamura
    JAERI/LINAC, Ibaraki-ken
  • S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Yoshii
    KEK, Ibaraki
  • M. Nomura, A. Schnase, M. Yamamoto
    JAERI, Ibaraki-ken
  We present the concept and the design of the low level RF (LLRF) control system of the J-PARC synchrotrons. The J-PARC synchrotrons are the rapid cycling 3-GeV synchrotron (RCS) and the 50-GeV main ring (MR) which require very precise and stable LLRF control systems to accelerate the ultra-high proton beam current. The LLRF system of the synchrotron is a full-digital system based on the direct digital synthesis (DDS). The functions of the system are (1) the multi-harmonic RF generation for the acceleration and the longitudinal bunch shaping, (2) the feedbacks for stabilizing the beam, (3) the feedforward for compensating the heavy beam loading, and (4) other miscellaneous functions such as the synchronization and chopper timing. The LLRF system of the RCS is now under construction. We present the details of the system. Also, we show preliminary results of performance tests of the control modules.  
 
WPAT066 ALS Booster Ring RF System Upgrade for Top-Off Mode of Operation booster, synchrotron, storage-ring, injection 3709
 
  • S. Kwiatkowski, K.M. Baptiste
    LBNL, Berkeley, California
  Funding: Supported by the U.S. Department of Energy under Contract No.DE-AC03-76SF00098.

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

 
 
WPAT075 Design and Calibration of a Phase and Amplitude Detector klystron, shielding, radiation
 
  • Z. Geng, P. Gu, H.Mi. Hou, G. Pei
    IHEP Beijing, Beijing
  The phase and amplitude detector (PAD) is a key unit of the phasing system for BEPCII linac. One of the main functions of the PAD is to measure the phase of each klystron accurately from such large noises. To meet the need of the phasing system, a new PAD is constructed based on I/Q demodulator and industrial computer. But the I/Q demodulator suffers form phase and amplitude mismatch, which can draw big error on phase measurement. In order to compensate the mismatch of the I/Q demodulator, we develop a calibration program using an adaptive method, LMS method. Almost all the mismatches of the I/Q demodulator are compensated after calibration.  
 
WPAT081 Ceramic Power Extractor Design at 15.6 GHz dipole, single-bunch, quadrupole, beam-transport 4078
 
  • A. Smirnov, Y. Luo, R. Yi, D. Yu
    DULY Research Inc., Rancho Palos Verdes, California
  Funding: Work supported by DOE SBIR Grant No. DE-FG03-01ER83232.

Power extractor and coupler designs developed for an experiment planned at the 12th beam harmonic of the upgraded Advanced Wakefield Accelerator (AWA) facility is described. New features are an upstream HOM dielectric damper with additional tapering, and a single-port coupler considered in two variants. Performance analysis includes coupler geometric tolerances, overvoltage, dipole mode wake and BBU; and wakefield losses induced in the damper.

 
 
WPAT083 Steering and Focusing Effects in TESLA Cavity Due to High Order Mode and Input Couplers focusing, coupling, simulation, electromagnetic-fields 4135
 
  • P. Piot
    Fermilab, Batavia, Illinois
  • M. Dohlus, K. Floettmann, M. Marx, S.G. Wipf
    DESY, Hamburg
  Funding: This work was supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U.S. Department of Energy, and by NICADD.

Many state-of-art electron accelerator proposals incorporate TESLA-type superconducting standing wave cavities. These cavities include input coupler (to feed the RF power into the cavity) and a pairs of high order mode couplers (HOM) to absorb the energy associated to HOM field excited as the bunch passes through the cavity. In the present paper we investigate, using numerical simulations, the impact of the input and HOM couplers on the beam dynamics. We show the overall effects are: a dipole kick (zeroth order) and normal and skew quadrupole-type focusing (first order). We present parametric studies of the strength of these effect for various operating gradients and incoming beam energies. We finally study the impact of this non-asymmetric field on the beam dynamics, taking as an example the low energy section of the European X-FEL injector.

 
 
WPAT084 A NEW DESIGN FOR A SUPER-CONDUCTING CAVITY INPUT COUPLER coupling, electron, vacuum, resonance 4141
 
  • H. Matsumoto, S. Kazakov, K. Saito
    KEK, Ibaraki
  Funding: Toshiba Electron Tube & Devices Co. Ltd., Tochigi, Otawa, Japan.

An attractive structure using capacitive coupling has been found for the input coupler for the 45 MV/m versions of the International Linear Collider (ILC) project. The coupler supports an electrical field gradient of ~1 kV/m around the rf window ceramic with 500 kW through power, a VSWR of 1.1 and a frequency bandwidth of 460 MHz. No unwanted resonances were found in the rf window near the first and second harmonics of the operation frequency.

 
 
WPAT085 4.2 K Operation of the SNS Cryomodules SNS, radiation, controls, Spallation-Neutron-Source 4173
 
  • I.E. Campisi, S. Assadi, F. Casagrande, M. Champion, C. Chu, S.M. Cousineau, M.T. Crofford, C. Deibele, J. Galambos, P.A. Gurd, D.R. Hatfield, M.P. Howell, D.-O. Jeon, Y.W. Kang, K.-U. Kasemir, Z. Kursun, H. Ma, M.F. Piller, D. Stout, W.H. Strong, A.V. Vassioutchenko, Y. Zhang
    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 being built at the Oak Ridge National Laboratory employs eighty one 805 MHz superconducting cavities operated at 2.1 K for the H- beam to gain energy in the main linac from 187 MeV to about 1 GeV. The superconducting cavities and cryomodules with two different values of beta .61 and .81 have been designed and constructed at Jefferson Lab for operation at 2.1 K with unloaded Q’s in excess of 5x109. To gain experience in testing cryomodules in the SNS tunnel before the final commissioning of the 2.1 K Central Helium Liquefier, integration tests were conducted on a medium beta (.61) cryomodule at 4.2 K. This is the first time that a superconducting cavity system specifically designed for 2.1 K operation has been extensively tested at 4.2 K without superfluid helium. Even at 4.2 K it was possible to test all of the functional properties of the cryomodule and of the cavities. In particular, at a nominal BCS Qo7x108, simultaneous pulse operation of all three cavities in the cryomodule was achieved at accelerating gradients in excess of 12 MV/m. These conditions were maintained for several hours at a repetition rate of 30 pps. Details of the tests will be presented and discussed.

 
 
WPAT091 Fabrication and Final Field Tuning of Copper Cavity Models for a High-Current SRF ERL at 703.75 MHz target 4257
 
  • M.D. Cole, A. Burger, M. Falletta, D. Holmes, E. Peterson, R. Wong
    AES, Medford, NY
  • I. Ben-Zvi
    BNL, Upton, Long Island, New York
  Advanced Energy Systems is currently under contract to BNL to fabricate a five cell superconducting cavity and cryomodule for the RHIC eCooler SRF Energy Recovery Linac (ERL) program.* The cavity is designed and optimized for ampere class SRF ERL service. As part of this program, we have fabricated two low power copper models of the RF cavities. During the fabrication process a series of frequency measurements were made and compared to the frequency expected at that point in the fabrication process. Where possible, the cavity was modified either before or during, the next fabrication step to tune the cavity frequency toward the target frequency. Following completion of the cavities they were tuned for field flatness and frequency. This paper will review the measurements made, frequency tuning performed, and discuss discrepancies between the expected and measured results. We will also review the as fabricated field profiles and the results of the tuning steps. Further, the cost and benefits of extensive in process tuning will be discussed from an industrial perspective.

*Electron cooling of RHIC, Ilan Ben-Zvi, these proceedings.

 
 
WOAB002 Status of the Shanghai Synchrotron Radiation Facility storage-ring, booster, synchrotron, injection 214
 
  • Z. Zhao, H. Ding, H. Xu
    SINAP, Shanghai
  The Shanghai Synchrotron Radiation Facility (SSRF) made its ground breaking at Zhang-Jiang High Tech Park on Dec.25, 2004 and moved into its construction phase with the plan of commencing user’s operation from April 2009. The SSRF complex is based on a 3.5GeV storage ring optimized to operate with top-up injection, mini-gap undulators and superconducting RF system, the 432m circumference storage ring provides 18 ID straight sections (4X12.0m and 16X6.5m), and four of them will be used for the first SSRF beam lines. The SSRF project was proposed in 1995, and since then it has experienced the conceptual design stage, the R&D program and the design optimization phase. This paper presents the updated design specifications and the construction status of the SSRF project.  
 
WOAB005 The Status of Turkic Accelerator Complex Proposal factory, luminosity, proton, electron 449
 
  • S. Sultansoy, M. Yilmaz
    Gazi University, Faculty of Science and Arts, Ankara
  • O. Cakir, A.K. Ciftci, E. Recepoglu, O. Yavas
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  Recently, the Turkic Accelerator Complex (TAC) is proposed as a regional facility for accelerator based fundamental and applied research. The complex will include linac on ring type electron-positron collider as a phi, charm and tau factory, linac based free electron laser (FEL), ring based third generation syncrothron radiation (SR) source and a few GeV proton accelerator. Preliminary estimations show that hundred inverse femto barn integral luminosity per year can be achieved for factory options. The FEL facility is planned to obtain laser beam between IR and soft X-ray region. In addition, SR facility will produce photon beams in UV and X-ray region. The proton accelerator will give opportunity to produce muon and neutron beams for applied research. The current status of the conceptual study of the complex is presented.  
 
WOAD002 Lepton Collider Operation with Constant Currents injection, background, luminosity, collimation 149
 
  • U. Wienands
    SLAC, Menlo Park, California
  Funding: Work supported by US DOE under contract DE-AC03-76SF00515

Traditionally, electron-positron colliders have been operating in a top-off-and-coast fashion with a cycle time depending on the beam life time, typically on the order of an hour. Each top-off involves ramping detector systems in addition to the actual filling time. The loss in accumulated luminosity is typically 20-50%. During the last year, both B-Factories have commissioned a continuous-injection mode of operation in which beam is injected without ramping the detector, thus raising luminosity integration by constant operation at peak luminosity. Constant beam currents reduce thermal drift and trips caused by change in beam loading. To achieve this level of operation, special efforts were made to reduce the injection losses and also to implement special gating procedures in the detectors, minimizing dead time. Bunch-injection control decides which bunch to inject into next while maintaining small charge variation between bunches. Beam collimation can reduce injection noise but also cause an increase in background rates. A challenge can be determining beam lifetime, important to maintain tuning of the beams. The paper will discuss the special features of continuous injection in both KEKB and PEP-II.

 
 
ROAC001 Testing of the SNS Superconducting Cavities and Cryomodules SNS, Spallation-Neutron-Source, vacuum, radiation 34
 
  • I.E. Campisi
    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 superconducting linac for the Spallation Neutron Source is in the process of being commissioned. Eighty-one cavities resonating at 805 MHz are installed in the SNS tunnel in 11 medium beta (.61) cryomodules each containing 3 cavities and 12 high beta (.81) cryomodules each with 4 cavities. The niobium cavities and cryomodules were designed and assembled at Jefferson Lab and installed in the SNS tunnel at Oak Ridge and are operating at 2.1 K. A preliminary test of one medium beta cryomodule was performed at 4.2 K in September 2004. All functional parameters of the cryomodule were proven to meet specifications at that temperature. The Central Helium Liquefier is being commissioned for 2.1 K operation and all cavities will be tested by late Spring 2005. The testing will include all of the functional parameters necessary for beam operation, to be carried out in summer 2005. The focus of the testing is to characterize the cavities’ maximum gradients and that sustained simultaneous operation can be achieved for all the cavities in preparation of beam commissioning. The results of cryomodule and cavity testing in the superconducting linac will be presented.

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

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

 
 
RPAE009 Design Considerations for the Stability Improvement of Klystron-Modulator for PAL XFEL undulator, power-supply, feedback, emittance 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.

 
 
RPAE013 Laser System for Photoelectron and X-Ray Production in the PLEIADES Compton Light Source laser, scattering, electron, photon 1347
 
  • D.J. Gibson, C.P.J. Barty, S.M. Betts, K. Crane, I. Jovanovic
    LLNL, Livermore, California
  Funding: This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

The PLEIADES (Picosecond Laser-Electron Interaction for the Dynamic Evaluation of Structures) facility provides tunable short x-ray pulses with energies of 30-140 keV and pulse durations of 0.3 – 5 ps by scattering an intense, ultrashort laser pulse off a 35-75 MeV electron beam. Synchronization of the laser and electron beam is obtained by using a photoinjector gun, and using the same laser system to generate the electrons and the scattering laser. The Ti:Sapphire, chirped pulse amplification based 500 mJ, 50 fs, 810 nm scattering laser and the similar 300 μJ, 5 ps, 266 nm photoinjector laser systems are detailed. Additionally, an optical parametric chirped pulse amplification (OPCPA) system is studied as a replacement for part of the scattering laser front end. Such a change would significantly simplify the set-up the laser system by removing the need for active switching optics, as well as increase the pre-pulse contrast ratio which will be important when part of the scattering laser is used as a pump beam in pump-probe diffraction experiments using the ultrashort tunable x-rays generated as the probe.

 
 
RPAE015 High Energy, High Brightness X-Rays Produced by Compton Back Scattering at the Livermore PLEIADES facility electron, laser, brightness, lattice 1464
 
  • A.M. Tremaine, S.G. Anderson, S.M. Betts, K. Crane, D.J. Gibson, F.V. Hartemann, J.S. Jacob
    LLNL, Livermore, California
  • P. Frigola, J. Lim, J.B. Rosenzweig, G. Travish
    UCLA, Los Angeles, California
  Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract no. W-7405-Eng-48.

PLEIADES (Picosecond Laser Electron Interaction for the Dynamic Evaluation of Structures) produces tunable 30-140 keV x-rays with 0.3-5 ps pulse lengths and 107 photons/pulse by colliding a high brightness electron beam with a high power laser. The electron beam is created by an rf photo-injector system, accelerated by a 120 MeV linac, and focused to 20 mm with novel permanent magnet quadrupoles. To produce Compton back scattered x-rays, the electron bunch is overlapped with a Ti:Sapphire laser that delivers 500 mJ, 80 fs, pulses to the interaction point. K-edge radiography at 115 keV on Uranium has verified the angle correlated energy spectrum inherent in Compton scattering and high-energy tunability of the Livermore source. Current upgrades to the facility will allow laser pumping of targets synchronized to the x-ray source enabling dynamic diffraction and time-resolved studies of high Z materials. Near future plans include extending the radiation energies to >400 keV, allowing for nuclear fluorescence studies of materials.

 
 
RPAE052 Overview of Accelerator Physics Studies and High Level Software for the Diamond Light Source booster, storage-ring, collimation, dipole 3188
 
  • R. Bartolini, A.I. Baldwin, M. Belgroune, C. Christou, V.C. Kempson, I.P.S. Martin, J.H. Rowland, B. Singh
    Diamond, Oxfordshire
  • D.J. Holder, J.K. Jones, S.L. Smith, J.A. Varley, N.G. Wyles
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  DIAMOND is a 3 GeV synchrotron light source under construction at Rutherford Appleton Laboratory in Oxfordshire (UK). The accelerators complex consists of a 100 MeV LINAC, a full energy booster and a 3GeV storage ring with 22 straight sections available for IDs. Installation of all three accelerators has begun, and LINAC commissioning is due to start in Spring 2005. This paper will give an overview of the accelerator physics activity to produce final layouts and prepare for the commissioning of the accelerator complex. The DIAMOND facility is expected to be operational for users in 2007  
 
RPAE055 Results of Preliminary Tests of PAR Bunch Cleaning booster, injection, storage-ring, synchrotron 3307
 
  • C. Yao, M. Borland, A. Grelick, A.H. Lumpkin, N. Sereno
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

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

 
 
RPAE058 NSLS-II Injection Concept injection, booster, emittance, 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 emittance, insertion, insertion-device, undulator 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.

 
 
RPAE078 Commissioning of SAGA Light Source electron, vacuum, injection, septum 4021
 
  • T. Tomimasu, Y. Iwasaki, S. Koda, Y. Takabayashi, K. Yoshida
    Saga Synchrotron Light Source, Industry Promotion Division, Saga City
  • H. Ohgaki
    Kyoto IAE, Kyoto
  • H. Toyokawa, M.Y. Yasumoto
    AIST, Ibaraki
  The SAGA Light Source (SAGA-LS) consists of a 250-MeV electron linac injector and an eight-hold symmetry 1.4-GeV storage ring with eight double-bend (DB) cell and eight 2.93-m long straight sections. The DB cell structure with a distributed dispersion system was chosen to produce a compact ring of 75.6-m long circumference. The machine construction begun September 29, 2003. The ring magnets of steel laminated structure, vacuum chambers made of aluminum alloy, pumping systems and four temperature controlled cooling water systems for the linac accelerating wave guides etc. were installed in March, 2004. The injector, a 500-MHz ring rf damped cavity, rf klystrons, beam transport systems for injection and their controlled systems were installed in July, 2004. The commissioning begun August 25, 2004. A 250-MeV beam was accelerated on September 29. The beam size is 1-mm in diameter and the energy spread is 0.8 % (FWHM). The first revolution of 250-MeV beam around the ring took place October 22. Beam was stored on November 12. The commissioning continues for beam storage and ramping to 1.4-GeV. We report a brief description of SAGA light source and early commissioning activities.  
 
RPAP004 Simulations for the Frankfurt Funneling Experiment simulation, rfq, beam-transport, ion 901
 
  • J. Thibus, A. Schempp
    IAP, Frankfurt-am-Main
  Funding: BMBF

Beam simulations for the Frankfurt Funneling Experiment are done with RFQSim and FUSIONS. RFQSim is a particle dynamic program to compute macro particle bunches in the 6D phase space through a RFQ accelerator. Behind the RFQ the simulation software FUSIONS calculates both beam lines through a r.f. funneling deflector. To optimise beam transport of existing and new funneling deflector structures FUSIONS is presently being developed. The status of the development of FUSIONS and the results will be presented.

 
 
RPAP006 X-Band Linac Beam-Line for Medical Compton Scattering X-Ray Source laser, photon, electron, scattering 994
 
  • K. Dobashi
    NIRS, Chiba-shi
  • M. Akemoto, H. Hayano, T. Higo, J.U. Urakawa
    KEK, Ibaraki
  • F. Ebina, A. Fukasawa, T. Kaneyasu, H. Ogino, F. Sakamoto, M. Uesaka, Y. Yamamoto
    UTNL, Ibaraki
  Compton scattering hard X-ray source for 10~80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U. Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard ( 10-80 keV) X-rays with the intensities of 108-10 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at the beam dump by adopting the deceleration of electrons after the Compton scattering. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2.5 J/10 ns is 107 photons/RF-pulse (108 photons/sec in 10 pps). X-band beam line for the demonstration is under commissioning. We also design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). The construction of the whole system starts. X-ray generation and medical application will be performed in this year.  
 
RPAP007 Alternating-Phase-Focused Linac with Interdigital H-Mode Structure for Medical Injectors rfq, electromagnetic-fields, medical-accelerators, injection 1084
 
  • Y. Iwata, T. Fujisawa, T. Furukawa, S. H. Hojo, T. Honma, M. Kanazawa, N. M. Miyahara, T. Murakami, M. Muramatsu, K. Noda, H. Ogawa, M. Torikoshi, S. Yamada, K. Yamamoto
    NIRS, Chiba-shi
  • Y.F. Fujii, T. Mitsumoto, H. Tsutsui
    SHI, Tokyo
  • T. Fujimoto, H.O. Ogawa
    AEC, Chiba
  • V.V. Kapin
    MEPhI, Moscow
  Tumor therapy using Heavy Ion Medical Accelerator in Chiba (HIMAC) has been performed at National Institute of Radiological Sciences (NIRS). With the successful clinical results over ten years, a project on developing compact accelerators has been started. To design these compact accelerators, a size of an injector as well as construction and operation costs plays an important role. To satisfy these requirements, we propose a compact injector consisting of a RFQ and Interdigital H-mode Drift-Tube-Linac (IH-DTL) having the resonant frequency of 200 MHz. The injector will accelerate carbon ion up to 4.0 AMeV. For the beam focusing of the IH-DTL, the method of Alternating-Phase-Focusing was employed. With the IH structure and rather high operating-frequency, the size of the cavities is compact; the radius is approximately 0.4 m, and the length of the RFQ and IH-DTL will be 2.5m and 3.5m respectively. The fabrication of the RFQ is in progress. For the IH-DTL, the full-scale model was fabricated. With the encouraging results of the electric field measurements, we are developing the final design of the IH-DTL. The fabrication of the entire injector will be completed at the end of 2005. The present status of our project will be shown.  
 
RPAP010 Development of Femtosecond and Attosecond Pulse Radiolysis by Using Laser Photocathode RF Gun S-Band Electron Linac electron, laser, gun, cathode 1198
 
  • Y. Yoshida, T. Kondo, J. Yang
    ISIR, Osaka
  Funding: Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science.

Femtosecond pulse radiolysis system based on linear accelerator was developed in Osaka University for study of radiation-induced ultra fast physical and chemical reactions. 35 MeV single electron pulse with pulse width of 100 fs was generated by using a laser photocathode rf gun s-band linac with a magnet pulse compression system. Femtosecond laser synchronized with the linac was used as analyzing light. Transient absorption was measured by the equivalent velocity spectroscopy which was a new method to get high time-resolution. Also, we have started the preliminary experiment on atosecond pulse radiolysis The double decker beam which is a new concept to realize the twin linac by using one linac will be used.

 
 
RPAP012 Dual Energy X-Ray CT by Compton Scattering Hard X-Ray Source scattering, electron, simulation, photon 1291
 
  • M. Uesaka, T. Kaneyasu
    UTNL, Ibaraki
  • K. Dobashi, M. Torikoshi
    NIRS, Chiba-shi
  We have developed a compact Compton scattering hard X-ray source at Nuclear Engineering Research Laboratory, University of Tokyo. The compact hard X-ray source can produce tunable monochromatic hard X-rays. The monochromatic hard X-rays are required in large field of medical and biological applications. We are planning to perform dual-energy X-ray CT, which enables us to measure atomic number Z distribution and electron density re distribution in a material. The hard X-ray source has an advantage to perform dual-energy X-ray CT. The X-ray energy can be changed quickly by introducing a fundamental frequency and a second harmonic frequency lasers. This quick energy change is indispensable to medical imaging and very difficult in a large SR light source and others. The information on the atomic number and electron density will be used for treatment plan in radiotherapy as well as for identification of materials in a nondestructive test. We examined applicability of the dual-energy X-ray CT for atomic number measurement for low to medium Z elements (Z=30) by considering the X-ray profile generated by Compton scattering. Details of the numerical simulations and plans of the dual-energy X-ray CT will be reported in the conference.  
 
RPAP023 RF-Based Accelerators for HEDP Research ion, extraction, focusing, target 1829
 
  • J.W.  Staples, R. Keller, A. Sessler
    LBNL, Berkeley, California
  • W. Chou
    Fermilab, Batavia, Illinois
  • P.N. Ostroumov
    ANL, Argonne, Illinois
  Funding: This work sponsored by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

Accelerator-driven High-Energy Density Physics experiments require typically 1 nanosecond, 1 microcoulomb pulses of mass 20 ions accelerated to several MeV to produce eV-level excitations in thin targets, the "warm dense matter" regime. Traditionally the province of induction linacs, RF-based acceleration may be a viable alternative with recent breakthroughs in accelerating structures and high-field superconducting solenoids. A reference design for an RF-based accelerator for HEDP research is presented using 15 T solenoids and multiple-gap RF structures configured with either multiple parallel beams (combined at the target) or a single beam and a small stacking ring that accumulates 1 microcoulomb of charge. In either case, the beam is ballistically compressed with an induction linac core providing the necessary energy sweep and injected into a plasma-neutralized drift compression channel resulting in a 1 mm radius beam spot 1 nanosecond long at a thin foil or low-density target.

 
 
RPAP025 A 7MeV S-Band 2998MHz Variable Pulse Length Linear Accelerator System gun, electron, vacuum, power-supply 1895
 
  • M. Hernandez, H. Deruyter, D. Skowbo, R.R. Smith
    Accuray, Inc, Mountain View, California
  • A.V. Mishin, A.J. Saverskiy
    AS&E, Billerica, Massachusetts
  American Science and Engineering High Energy Systems Division (AS&E HESD) has designed and commissioned a variable pulse length 7 MeV electron accelerator system. The system is capable of delivering a 7 MeV electron beam with a pulse length of 10 nS FWHM and a peak current of 1 ampere. The system can also produce electron pulses with lengths of 20, 50, 100, 200, 400 nS and 3 uS FWHM with corresponding lower peak currents. The accelerator system consists of a gridded electron gun, focusing coil, an electrostatic deflector system, Helmholtz coils, a standing wave side coupled S-band linac, a 2.6 MW peak power magnetron, an RF circulator, a fast toroid, vacuum system and a PLC/PC control system. The system has been operated at repetition rates up to 250pps. The design, simulations and experimental results from the accelerator system are presented in this paper.  
 
RPAP027 Portable X-Band Linear Electron Accelerators for Radiographic Applications radiation, coupling, electron, injection 1985
 
  • A.J. Saverskiy, H. Deruyter, M. Hernandez, A.V. Mishin, D. Skowbo
    AS&E, Billerica, Massachusetts
  The MINAC series portable linear electron accelerator systems designed and manufactured at American Science and Engineering, Inc. High Energy Systems Division (AS&E HESD) are discussed in this paper. Each system can be configured as either an X-ray or electron beam source. The powerful 4 MeV and 6 MeV linacs powered by a 1,5 MW magnetron permit operation in a dose rate range from 100 R/min at 80 cm to 600 R/min at 80 cm. Each MINAC is a self-contained source with radiation leakage outside of the X-ray head less than 0,1% of the maximum dose. Along with these systems a 1 MeV ultra compact MINAC has been successfully tested. The unit is available with radiation leakage less then 0.01% and permits producing X-ray beam in an energy range (12) MeV at a high output dose rate. Design and experimental parameters are presented. The common and system specific features are also discussed.  
 
RPAP035 Photonuclear and Radiation Effects Testing with a Refurbished 20 MeV Medical Electron Linac radiation, electron, photon, target 2363
 
  • T. Webb, L.C. DeVeaux, F. Harmon, J.E. Petrisko, R.J. Spaulding
    IAC, Pocatello
  • R. Assink
    Sandia National Laboratories, Albuquerque, New Mexico
  • W. Beezhold
    ISU, Pocatello, Idaho
  An S-band 20 MeV electron linear accelerator formerly used for medical applications has been recommissioned to provide a wide range of photonuclear activation studies as well as various radiation effects on biological and microelectronic systems. Four radiation effect applications involving the electron/photon beams are described. Photonuclear activation of a stable isotope of oxygen provides an active means of characterizing polymer degradation. Biological irradiations of microorganisms including bacteria were used to study total dose and dose rate effects on survivability and the adaptation of these organisms to repeated exposures. Microelectronic devices including bipolar junction transistors (BJTs) and diodes were irradiated to study photocurrent from these devices as a function of peak dose rate with comparisons to computer modeling results. In addition, the 20 MeV linac may easily be converted to a medium energy neutron source which has been used to study neutron damage effects on transistors.  
 
RPAP036 A Compact 5 MeV S-Band Electron Linac Based X-Ray Source for Industrial Radiography electron, target, collimation, insertion 2428
 
  • L. Auditore, R.C. Barnà, D. De Pasquale, U. Emanuele, A. Trifirò, M. Trimarchi
    INFN & Messina University, S. Agata, Messina
  • A. Italiano
    INFN - Gruppo Messina, S. Agata, Messina
  A compact and reliable X-ray source, based on a 5 MeV, 1 kW, S-band electron linac, has been set up at the Dipartimento di Fisica, Universit\‘a di Messina. This source, coupled with a GOS scintillator screen and a CCD camera, represents an innovative transportable system for industrial radiography and X-ray tomography. Optimization of the parameters influencing the e-gamma conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 code. The converter choice is the result of the study of the e-gamma conversion performances for different materials and materials thicknesses. Also the converter position with respect to the linac exit window was studied. The chosen converter consists in a Ta-Cu target inserted close to the linac window. The Cu layer acts as a filter both on the electrons from the source and on the low energy X-rays. The X-ray beam angular profile was studied by means of GafChromic films with and without collimation. In the final source project, a collimation system provides a 14 cm diameter X-ray spot at the sample position and first radiographyc results were obtained by inspecting different density materials and thicknesses.  
 
RPAP037 Study of the Dynamics in a Linac Booster for Proton Therapy in the 30-62 MeV Energy Range proton, cyclotron, booster, coupling 2494
 
  • V.G. Vaccaro
    Naples University Federico II and INFN, Napoli
  • T. Clauser, A. Rainò
    Bari University, Science Faculty, Bari
  • C. De Martinis, D. Giove, M. Mauri
    INFN/LASA, Segrate (MI)
  • S. Lanzone
    Naples University Federico II, Napoli
  • M.R. Masullo
    INFN-Napoli, Napoli
  • V. Variale
    INFN-Bari, Bari
  Funding: Istituto Nazionale di Fisica Nucleare (Naples, Milan and Bari).

Recent results in accelerator physics have shown the feasibility of a coupling scheme between a cyclotron and a linac for proton acceleration. Cyclotrons with energies up to 30 MeV, mainly devoted to radioisotopes production, are available in a large number of medical centres. These two evidences have suggested the idea to study and design a linac booster able to increase the initial proton energy up to the values required for the treatment of tumors, like the ocular ones. Among the challenges in such a project one of the main ones is related to meet the requirement of having sufficient mean current for therapy from a given injection current coming from the cyclotron. In this paper we will review the rationale of the project in order to optimize the transmittance and to minimize the duty-cycle. In this frame we will discuss the basic design of a compact 3GHz linac with a new approach to the cavities used in a SCL (Side Coupled Linac) structure.

 
 
RPAP038 An Advantage of the Equivalent Velocity Spectroscopy for Femtsecond Pulse Radiolysis electron, laser, gun, emittance 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.

 
 
RPAP046 Real-Time Beam Loss Monitor Display Using FPGA Technology beam-losses, synchrotron, background, monitoring 2914
 
  • M.R.W. North, A.H. Kershaw
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  This paper outlines the design of a Real-time Beam Loss Monitor Display for the ISIS Synchrotron based at Rutherford Appleton Laboratory (Oxon, UK). Beam loss is monitored using 39 argon filled ionisation chambers positioned around the synchrotron, the levels of which are sampled four times in each cycle. The new BLM display acquires the signals and displays four histograms, each relating to an individual sample period; the data acquisition and signal processing required to build the display fields are completed within each machine cycle (50 Hz). Attributes of the new system include setting limits for individual monitors; displaying over-limit detection, and freezing the display field when a beam trip has occurred. The design is based around a reconfigurable Field Programmable Gate Array, interfacing to a desktop monitor via the VGA standard. Results gained using simulated monitor signals have proven the system.  
 
RPAP047 DAQ System of BPM and BCT for the BEPCII Linac positron, pick-up, monitoring, electron 2980
 
  • J. Cao, Q. Ye
    IHEP Beijing, Beijing
  Following the BEPCII upgrade, total about 19 BPM and 12 BCT have been newly installed in the BEPCII Linac. Also, a set of distributed control system based on EPICS architecture has been built, and the BPM and BCT system are merged into the new control system for the data acquisition. In order to reduce the effects of RF noise, a special gated integrator was used to measure the beam current. In this paper we will describe the DAQ system of BPM and BCT including calibrations in detail.  
 
RPAT006 Design and Initial Tests of a Gas Scattering Energy Monitor in the PEFP RFQ and DTL scattering, proton, energy-calibration, rfq 997
 
  • S.-H. Han, Y.-S. Cho
    KAERI, Daejon
  Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government.

We have developed a gas scattering energy monitor to measure the energy spectrum of the proton beam at the end of 3MeV RFQ and 20MeV DTL for the low energy part of the PEFP(Proton Engineering Frontier Project). The energy monitor is comprised of a Xe scattering chamber, two collimators to reduce the beam intensity, and a surface barrier detector for measuring the proton energy. In order to measure the beam current simultaneously, a faraday cup is incorporated into the energy monitor. The calculated flux attenuation through the 0.2 mm diameter collimator is 3·10-4 and the energy loss is 28 keV. We report on design details and multiple gas scattering of proton beams in Xe gas by using a SRIM code.

 
 
RPAT007 Status of Beam Diagnostic Systems for the PEFP proton, diagnostics, instrumentation, pick-up 1090
 
  • J.H. Park, J.Y. Huang, W.H. Hwang, Y.W. Parc, S.J. Park
    PAL, Pohang, Kyungbuk
  • Y.-S. Cho, B.H. Choi, S.-H. Han
    KAERI, Daejon
  Funding: Supported by the PEFP (Proton Engineering Frontier Project).

A proton linear accelerator is currently the construction at the KAERI (Korea Atomic Research Institute) to the PEFP (Proton Engineering Frontier Project) in Korea. We are accomplished the technique development of beam diagnostic system to be currently the construction. We treat beam diagnostics for the high power proton linear accelerator. Prototype beam position & phase monitor (BPPM) electronics was made and tested successfully in one of the beam diagnostic systems. The beam position monitor pickup electrode is a capacitive type (electrostatic type) which has a button form. Button form electrode, in common use around electron synchrotrons and storage rings, are a variant of the electrode with small button form (e.g., sub mm diameter). However, we are designed button form electrode to measure beam position of proton beam. The BCM (Beam Current Monitor) is developed Tuned CT (Current Transformer) for collaborate with Bergoz Instruments. This paper describes the status of beam diagnostic systems for the PEFP.

 
 
RPAT008 Prototype Digital Beam Position and Phase Monitor for the 100-MeV Proton Linac of PEFP proton, monitoring, instrumentation, SNS 1120
 
  • I.H. Yu, D.T. Kim, S.-C. Kim, I.-S. Park, S.J. Park
    PAL, Pohang, Kyungbuk
  • Y.-S. Cho
    KAERI, Daejon
  Funding: Work supported by the PEFP (Proton Engineering Frontier Project), Korea.

The PEFP (Proton Engineering Frontier Project) at the KAERI (Korea Atomic Energy Research Institute) is building a high-power proton linear accelerator aiming to generate 100-MeV proton beams with 20-mA peak current (pulse width and max. repetition rate of 1 ms and 120 Hz respectively). We are developing a prototype digital BPPM (Beam Position and Phase Monitor) for the PEFP linac utilizing the digital technology with field programmable gate array (FPGA). The RF input signals are down converted to 10 MHz and sampled at 40 MHz with 14-bit ADC to produce I and Q data streams. The system is designed to provide a position and phase resolution of 0.1% and 0.1? RMS respectively. The fast digital processing is networked to the EPICS-based control system with an embedded processor (Blackfin). In this paper, the detailed description of the prototype digital beam position and phase monitor will be described with the performance test results.

 
 
RPAT019 Use of a Reconfigurable VME Module To Measure Beam Energy at the Los Alamos Proton Storage Ring proton, injection, storage-ring, pick-up 1658
 
  • R. Merl, T. Spickermann
    LANL, Los Alamos, New Mexico
  Funding: U.S. Department of Energy.

Custom instrumentation has been developed at the Los Alamos Neutron Science Center to measure the Proton Storage Ring (PSR) beam energy. The PSR accumulates up to 4x1013 protons from the linear accelerator for delivery to a spallation neutron source. The energy of the beam injected into the PSR must be adjusted so that the revolution frequency matches the ring buncher frequency, otherwise a large momentum spread will cause increased losses in high-dispersion areas. Errors in injected beam energy appear as deviations from the ideal revolution frequency. A low-cost, custom, reconfigurable VME module has been adapted to calculate the PSR revolution frequency in real-time. The module connects directly to an analog wall current monitor output and uses analog signal conditioning electronics, an analog to digital converter, field programmable gate arrays, and an embedded floating-point digital signal processor to calculate the revolution frequency. This is an improvement over the previously used method of manually measuring the frequency with an oscilloscope. Accelerator physicists can now simply observe the PSR frequency, which is dependent on beam energy, on a control room display.

LA-UR-04-8661.

 
 
RPAT040 Matching BPM Stripline Electrodes to Cables and Electronics impedance, SNS, dipole, simulation 2607
 
  • C. Deibele
    ORNL, Oak Ridge, Tennessee
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico
  Funding: This work was supported by SNS through UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. The 805-MHz coupled-cavity linac (CCL) accelerates an H- beam from 86 to 186 MeV, while the 805 MHz superconducting-cavity linac (SCL) accelerates the beam to its final energy of 1 GeV. The SNS beam position monitors (BPMs) which are used to measure both position and phase of the beam relative to the master oscillator, have the dual-planed design with four one-end-shorted stripline electrodes. We argue that the BPMs are optimally broadband matched to the cabling and electronics when the geometrical mean of the sum-mode and quadrupole-mode impedances is equal to the external-line impedance, 50 Ohms. The analytical results, MAFIA and HFSS simulations, wire measurements, and beam measurements that support this statement are presented.

 
 
RPAT043 Developments of the Calibration Tools for Beam Position Monitor at J-PARC Linac quadrupole, beam-losses, proton, beam-transport 2777
 
  • S. Sato, H. Akikawa, T. Tomisawa, A. Ueno
    JAERI/LINAC, Ibaraki-ken
  • Z. Igarashi, M. Ikegami, N. Kamikubota, S. Lee, T. Toyama
    KEK, Ibaraki
  In the J-PARC LINAC, there are mainly two requirements for the beam based calibration of beam position monitors (BPMs). One is that BPMs need to be calibrated with the accuracy of about a hundred micro-meters to minimize beam loss for the world highest class of proton intensity. The other is that about a hundred of BPMs need to be calibrated consistently. To achieve these requirements, the calibration tool are being developed with experiences on real beam in a MEBT line set for the DTL commissioning. Tools for simulating the beam trajectory using transport matrix (e.g. T3D) are being developed as well. The calibrated beam positions measured by BPMs are used in the simulation for tuning the beam. Implementation of the calibration tools on the same platform (e.g. SAD) with the simulation tools is important for higher usability during commissioning of whole J-PARC. In this paper, details of these developments around BPMs are to be reported.  
 
RPAT050 Electro Optic Bunch Length Measurements at the VUV-FEL at DESY laser, electron, polarization, free-electron-laser 3111
 
  • B. Steffen, S. Casalbuoni, E.-A. Knabbe, H. Schlarb, B. Schmidt
    DESY, Hamburg
  • P. Schmüser, A. Winter
    Uni HH, Hamburg
  For the operation of a SASE FEL, the longitudinal bunch length is one of the most critical parameters. At the superconducting linac of the VUV-FEL at DESY, we have installed an electro optic sampling (EOS) experiment to probe the time structure of the electric field of the bunches to better than 100 fs rms. The field-induced birefringence of a ZnTe crystal is detected by a femtosecond laser pulse (TiSa) and the time structure is measured by scanning the relative timing of the electron bunch and the TiSa pulse. A synchronization stability of better than 50 fs between laser and accelerator RF has been achieved. First results on the synchronization measurements and for the bunch length as function of the linac parameters are presented.  
 
RPAT054 Beam Position Monitor at the PLS BTL electron, monitoring, pick-up, injection 3289
 
  • S.-C. Kim, M.-H. Chun, Y.J. Han, J.Y. Huang, D.T. Kim, W.W. Lee
    PAL, Pohang, Kyungbuk
  Funding: Work supported by the Ministry of Science and Technology, Korea.

Electron Linac at the Pohnag Accelerator Laboratory (PAL) has been operated continuously as the full energy injector for storage ring. Linac and storage ring energy has been 2.0 GeV since Dec. 1994, and 2.5 GeV since Oct. 2002. In Aug. 2004, thirteen BPMs are newly installed at BTL(Beam Transport Line) for beam trajectory measurement and feedback. These BPMs consist of 100mm strip-line electrodes in 150mm long chamber, and 500MHz log-ratio signal processing circuits. BPM data acquisition system is developed as EPICS IOC using NI S-series data acquisition board and NI LabView 7.1. BTL BPMs will be used for optic correction and beam energy feedback for PLS beam injection. This paper describes on design, test results, installation and data acquisition system of the PLS BTL BPM.

 
 
RPAT065 A Wire Scanner Design for Electron Beam Profile Measurement in the Linac Coherent Light Source Undulator electron, undulator, vacuum, impedance 3667
 
  • J.L. Bailey, T.W. Buffington, B.X. Yang
    ANL, Argonne, Illinois
  Funding: Work supported by U. S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.

The Linac Coherent Light Source (LCLS), currently under design, requires beam diagnostic instruments between the magnets in the beam undulator section. Ten wire scanners are planned as one of the primary instruments to characterize electron beam properties. The development of these wire scanners presents several design challenges due to the need for high accuracy and resolution of the wire motion (3 microns tolerance, typical) and the high intensity of the beam (3400 A over an area of 30 micron rms radius). In this paper, we present the technical specification and design criteria for the scanners. We will also present the mechanical design of the UHV-compatible drive and its engineering analysis. Lastly, we present the wire card design and discuss associated thermal and mechanical issues originating from the highly intense x-ray and electron beams.

 
 
RPAT071 Digital Beam Position Monitor for the Happex Experiment instrumentation, controls, monitoring, survey 3841
 
  • S.R. Kauffman, H. Dong, A. Freyberger, L. Kaufman, J. Musson
    Jefferson Lab, Newport News, Virginia
  Funding: This work was supported by DOE contract No. DE-AC05-84ER40150.

The proposed HAPPEX experiment at CEBAF employs a three cavity monitor system for high-precision (1 mm), high-bandwidth (100 kHz) position measurements. This is performed using a cavity triplet consisting of two TM110-mode cavities (one each for X and Y planes) combined with a conventional TM-010-mode cavity for a phase and magnitude reference. Traditional systems have used the TM010 cavity output to directly down convert the BPM cavity signals to base band. The Multi-channel HAPPEX digital receiver simultaneously I/Q samples each cavity and extracts position using a CORDIC algorithm. The hardware design consists of a digital receiver daughter board and digital processor motherboard that resides in a VXI crate. The daughter board down converts 1.497 GHz signals from the TM010 cavity and X and Y signals from the TM110 cavities to 4 MHz, and extracts the quadrature digital signals. The motherboard processes this data and computes beam intensity and X-Y positions with a resolution of one mm, 100 kHz output bandwidth, and overall latency of ten microseconds. The results are available in both analog and digital format.

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

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

 
 
RPAT087 Design of a High-Resolution Optical Transition Radiation Imager System for the Linac Coherent Light Source Undulator electron, undulator, optics, radiation 4209
 
  • B.X. Yang, J.L. Bailey, S.J. Stein, D.R. Walters
    ANL, Argonne, Illinois
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.

The Linac Coherent Light Source (LCLS), a free-electron x-ray laser, is under design and construction. Its high intensity electron beam, 3400 A in peak current and 46 TW in peak power, is concentrated in a small area (30 micrometer rms in both horizontal and vertical directions) inside its undulator. Ten optical transition radiation (OTR) imagers are planned between the undulator segments for the characterization of the transverse profiles of the electron beam. In this paper, we present the performance requirements and technical requirements of the OTR imagers. We will discuss in detail the design of the OTR screen, the arrangement and modeling of the imaging optics, and the mechanical design and analysis of the compact camera module. Through a unique optical arrangement, this imager will achieve a fine resolution (12 micrometer rms or better) over the entire field of view (5 mm × 5 mm). The compact camera module will fit in the limited space available with remote focus adjustment. A digital camera will be used to read out the beam images in a programmable region (5 mm × 0.5 mm) at the full beam repetition rate (120 Hz), or over the entire field at a lower rate (15 Hz).

 
 
RPAT088 Energy-Spread-Feedback System for the KEKB Injector Linac feedback, electron, target, positron 4212
 
  • M. Satoh, K.  Furukawa, T. Suwada
    KEK, Ibaraki
  New energy-spread feedback system using nondestructive energy-spread monitors have been developed in order to control and stabilize the energy spreads of single-bunch electron and positron beams in the KEKB injector linac. The well-controlled feedback systems of the injector linac are successfully working in dairy operation not only for keeping the injection rate higher along with the beam-orbit and energy feedback systems but also for reducing a background level to the high-energy B-factory experiment. The energy spreads of the injection beams are well stabilized within 0.2%, 0.5% and 0.3% for the electron beam, the positron beam, and the high-current primary electron beam for positron production, respectively, through the energy-spread feedback system under the nominal operation condition. In this paper, we will report in detail the energy-spread feedback system using the nondestructive energy-spread monitors with multi-strip-line electrodes and their performance in the KEKB operation.  
 
RPAT091 Longitudinal Electron Bunch Diagnostics Using Coherent Transition Radiation electron, radiation, simulation, laser 4254
 
  • D. Mihalcea, C.L. Bohn
    Northern Illinois University, DeKalb, Illinois
  • U. Happek
    UGA, Athens, Georgia
  • P. Piot
    Fermilab, Batavia, Illinois
  The longitudinal charge distribution of electron bunches in the Fermilab A0 photo-injector was determined by using the coherent transition radiation produced by electrons passing through a thin metallic foil. The auto-correlation of the transition radiation signal was measured with a Michelson type interferometer. The response function of the interferometer was determined from measured and simulated power spectra for low electron bunch charge and maximum longitudinal compression. Kramers-Kroning technique was used to determine longitudinal charge distribution. Measurements were performed for electron bunch lengths in the range from 0.3 to 2 ps (rms).  
 
RPAT094 Femtosecond Synchronisation of Ultrashort Pulse Lasers to a Microwave RF Clock laser, monitoring, resonance, feedback 4299
 
  • A. Winter
    Uni HH, Hamburg
  • N. Ignashin, A. Simonov, S. Sytov
    IHEP Protvino, Protvino, Moscow Region
  • E.-A. Knabbe, S. Simrock, B. Steffen
    DESY, Hamburg
  A precise synchronization between the laser repetition rate and the linac-RF is mandatory for electro-optic sampling or pump-probe experiments. The level of stability is usually determined by measuring of the spectral noise power density of the feedback signal when the system is locked. However, an independent measurement is needed to confirm this. In this paper, we present an approach exploiting electronic techniques to synchronize a TiSa laser to the RF of the DESY VUVFEL with sub-50 fs stability. The remaining time jitter is measured by an RF monitoring system independent of the locking PLL.  
 
ROAD003 Post-Irradiation Properties of Candidate Materials for High-Power Targets proton, target, radiation, booster 333
 
  • H.G. Kirk, H. Ludewig, L.F. Mausner, N. Simos, P. Thieberger
    BNL, Upton, Long Island, New York
  • Y. Hayato, K. Yoshimura
    KEK, Ibaraki
  • K.T. McDonald
    PU, Princeton, New Jersey
  • J. Sheppard
    SLAC, Menlo Park, California
  • L.P. Trung
    Stony Brook University, Stony Brook
  Funding: U.S. DOE.

The long term survivability of materials which can be used either for high-intensity targets or for the environment surrounding the target can be greatly influenced by how the physical properties of the material are altered by radiation damage. We have irradiated several candidate materials and report here on physical properties before and after irradiation.

 
 
RPPE001 The CARE Accelerator R&D Programme in Europe electron, proton, acceleration, hadron 749
 
  • O. Napoly, R. Aleksan, A. Devred
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • A. Den Ouden
    Twente University, Laser Physics and Non-Linear Optics Group, Enschede
  • R. Garoby, R. Losito, L. Rinolfi, F. Ruggiero, W. Scandale, D. Schulte, M. Vretenar
    CERN, Geneva
  • T. Garvey, F. Richard
    LAL, Orsay
  • A. Ghigo
    INFN/LNF, Frascati (Roma)
  • E. Gschwendtner
    CUI, Geneva
  • H. Mais, D. Proch
    DESY, Hamburg
  • V. Palladino
    INFN-Napoli, Napoli
  Funding: This work is supported by the European Community-Research Infrastructure Activity under the FP6 “Structuring the European Research Area” programme (CARE, contract number RII3-CT-2003-506395).

CARE, an ambitious and coordinated programme of accelerator research and developments oriented towards HEP projects, has been launched in January 2004 by the main European laboratories and the European Commission within the 6th Framework Programme. This programme aims at improving existing infrastructures dedicated to future projects such as linear colliders, upgrades of hadron colliders and high intensity proton drivers. An important part of this programme is devoted to advancing the performance of the superconducting technology, both in the fields of RF cavities for electron and proton acceleration and of high field magnets, as well as to developing high intensity electron and proton injectors. We describe the R&D plans of the four main R&D activities and report on the results and progress obtained so far.

 
 
RPPE003 Operational Experience of Cooling Water Systems for Accelerator Components at PLS storage-ring, power-supply, higher-order-mode, klystron 850
 
  • K.R. Kim, C.W. Chung, H.S. Han, H.-G. Kim, Y.-C. Kim, I.S. Ko, B.H. Lee
    PAL, Pohang, Kyungbuk
  Funding: Work supported by MOST and POSCO in Republic of Korea.

The cooling water system has been utilized for absorbing heat generated by a multitude of electromagnetic power delivering networks at PLS. The separate cooling water distribution systems for the storage ring, beam transport line and linear accelerator have been operated with a different operating temperature of supplying water. All water used for heat removal from the accelerator components are deionised and filtered to provide with over 2 MO-cm specific resistance. The operating pressures and flows of input water are also controlled with flow balancing scheme at a specified range. The operating temperature of components in the accelerator is sustained as tight as below ±0.1 deg C to minimize the influence of temperature fluctuation on the beam energy and stability. Although the PLS cooling systems were initially installed with a high degree of flexibility to allow for easy maintenance, a number of system improvements have been employed to enhance operational reliability and to incorporate the newly developed operating interfaces such as EPICS accelerator control systems. The important design and operational features of PLS cooling water systems are presented as well as lessons learned from around 10-years normal operation.

 
 
RPPE005 Ions for LHC: Beam Physics and Engineering Challenges ion, electron, injection, luminosity 946
 
  • S. Maury, M.-E. Angoletta, V. Baggiolini, A. Beuret, A. Blas, J. Borburgh, H.-H. Braun, C. Carli, M. Chanel, T. Fowler, S.S. Gilardoni, M. Gourber-Pace, S. Hancock, C.E. Hill, M. Hourican, J.M. Jowett, K. Kahle, D. Kuchler, E. Mahner, D. Manglunki, M. Martini, M.M. Paoluzzi, J. Pasternak, F. Pedersen, U. Raich, C. Rossi, J.-P. Royer, K. Schindl, R. Scrivens, L. Sermeus, E.N. Shaposhnikova, G. Tranquille, M. Vretenar, Th. Zickler
    CERN, Geneva
  The first phase of the heavy ion physics program at the LHC aims to provide lead-lead collisions at energies of 5.5 TeV per colliding nucleon pair and ion-ion luminosity of 1027 cm-2s-1. The transformation of CERN’s ion injector complex (Linac3-LEIR-PS-SPS) presents a number of beam physics and engineering challenges. Conversion of the Low Energy Antiproton Ring (LEAR) to a Low Energy Ion Ring (LEIR) is under way: the high-current electron cooling system, novel broad-band RF cavities and vacuum equipment to achieve 10-12 mbar are the major challenges. Commissioning of LEIR with beam will start in the middle of 2005. Major hardware changes in Linac3 include the installation of the new ECR ion source and of the energy ramping cavity. The PS will have a new injection system and RF gymnastics. A stripping insertion between PS and SPS must not disturb the proton operation. In the LHC itself, there are fundamental performance limitations due to various beam loss mechanisms. To study these without risk of damage there will be an initial period of operation with a reduced number of nominal intensity bunches. While reducing the work required to commission the LHC with ions in 2008, this will still enable early physics discoveries.  
 
RPPE009 Extremely High Current, High-Brightness Energy Recovery Linac electron, gun, emittance, 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.

 
 
RPPE012 Grounding of SNS Accelerator Structure klystron, SNS, impedance, instrumentation 1278
 
  • P.S. Holik
    ORNL, Oak Ridge, Tennessee
  Funding: UT-Battelle, SNS Collaboration.

Description of site general grounding network. RF grounding network enhancement underneath the klystron gallery building. Grounding network of the Ring Systems with ground breaks in the Ring Tunnel. Grounding and Bonding of R&D accelerator equipment. SNS Building lightning protection.

*SNS SRD *IEEE GREEN BOOK *IEEE EMERALD BOOK

 
 
RPPE014 Temperature Regulation of the Accelerating Section in CANDLE Linac feedback, simulation, resonance, radio-frequency 1416
 
  • S. Tunyan, G.A. Amatuni, B. Grigoryan
    CANDLE, Yerevan
  The temperature of the CANDLE S-Band Linac high-power RF components will be regulated by stand-alone closed loop (SACL) water system. The RF components are made of oxygen-free high conductivity copper and respond quickly to temperature changes. Temperature stabilization better than ± 0.1 C is required to achieve a good RF phase and energy stability. The temperature regulation and control philosophy along with the simulation results are discussed.  
 
RPPE015 Diagnostics and Protection Control for IREN Linac Test Facility diagnostics, electron, monitoring, instrumentation
 
  • V.N. Zamriy
    JINR, Dubna, Moscow Region
  The diagnostic and protection control systems for the full-scale test facility of the linear electron accelerator are constructed according to the project on pulsed neutron source IREN. Combined control schemes of timed diagnostics of a duty cycle and real-time protection control are created for the linac test facility. Applicability of the diagnostics systems of cycle parameters and deviations of a status for control of the mode of protection is shown. Multichannel control modules of the protection system have been developed for logging and diagnostics of a status change, the alarms and control of a mode of operation. The applied multiway controllers for duty protection with fast locking of cycles of the IREN linac are presented.  
 
RPPE022 Machine Protection System for Concurrent Operation of RHIC and BLIP proton, controls, radiation, monitoring 1754
 
  • M. Wilinski, S. Bellavia, J. Glenn, L.F. Mausner, K.L. Unger
    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.

The Brookhaven 200 MeV linac is a multipurpose machine used to inject low intensity polarized protons ultimately ending up in RHIC as well as to inject high intensity protons to BLIP, a medical isotope production facility. If high intensity protons were injected to RHIC by mistake, administrative radiation limits could be exceeded or sensitive electronics could be damaged. In the past, the changeover from polarized proton to high intensity proton operation has been a lengthy process, thereby never allowing the two programs to run simultaneously. To remedy this situation and allow for concurrent operation of RHIC and BLIP, an active interlock system has been designed to monitor current levels in the AGS using two current transformers with fail safe circuitry and associated electronics to inhibit beam to RHIC if high intensity is detected.

 
 
RPPE029 Rotating Aperture Deuterium Gas Cell Development for High Brightness Neutron Production vacuum, beam-transport, optics, target 2074
 
  • B. Rusnak, M. Hall, S. Shen
    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.

A project is underway at LLNL to design and build a system for fast neutron imaging. The approach being pursued will use a 7 MeV deuterium linac for producing high-energy neutrons via a D(d,n)3He reaction. To achieve a high-brightness neutron source, a windowless rotating aperture gas cell approach is being employed. Using a series of close-tolerance rotor and stator plates, a differential pumping assembly has been designed and built that contains up to 3 atmospheres of deuterium gas in a 40 mm long gas cell. Rarefaction of the gas due to beam-induced heating will be addressed by rapidly moving the gas across the beam channel in a crossflow tube. The design and fabrication process has been guided by extensive 3D modeling of the hydrodynamic gas flow and structural dynamics of the assembly. Summaries of the modeling results, the fabrication and assembly process for the rotating aperture system, and initial measurements of gas leakage shall be presented.

 
 
RPPE032 Measurement of the Secondary Emission Yield of a Thin Diamond Window in Transmission Mode electron, vacuum, gun, cathode 2251
 
  • X.Y. Chang, I. Ben-Zvi, A. Burrill, S. Hulbert, P.D.J. Johnson, J. Kewisch, T. Rao, Z. Segalov, J. Smedley, Y. Zhao
    BNL, Upton, Long Island, New York
  The secondary emission enhanced photoinjector (SEEP) is a promising new approach to the generation of high-current, high-brightness electron beams. A low current primary electron beam with energy of a few thousand electron-volts strikes a specially prepared diamond window which emits secondary electrons with a current two orders of magnitude higher. The secondary electrons are created at the back side of the diamond and drift through the window under the influence of a strong electrical field. A hydrogen termination at the exit surface of the window creates a negative electron affinity (NEA) which allows the electrons to leave the diamond. An experiment was performed to measure the secondary electron yield and other properties. The results are discussed in this paper.  
 
RPPE045 Vacuum Pumping Performance Comparison of Non-Evaporable Getter Thin Films Deposited Using Argon and Krypton as Sputtering Gases vacuum, cathode, laser, target 2860
 
  • X. Liu, Y. He, Y. Li
    Cornell University, Department of Physics, Ithaca, New York
  • M.R. Adams
    Cornell University, Ithaca, New York
  Funding: Work Supported by the National Science Foundation.

Owing to the outstanding vacuum performance and the low secondary electron yield, non-evaporable getter (NEG) thin film deposited onto interior walls has gained widespread acceptance and has been incorporated into many accelerator vacuum system designs. The titanium-zirconium-vanadium (T-Zr-V) NEG thin films were deposited onto the interior wall of stainless steel pipes via DC magnetron sputtering method using either argon or krypton gas as sputtering gas. Vacuum pumping evaluation tests were carried out to compare vacuum pumping performances of the Ti-Zr-V NEG thin films deposited using argon or krypton. The results showed much higher initial pumping speed for the Kr-sputtered NEG film than the Ar-sputtered film, though both films have similar activation behavior. The compositions and textures of both thin films were measured to correlate to the pumping performances.

 
 
RPPE060 Overview of SNS Cryomodule Performance SNS, vacuum, resonance, klystron 3496
 
  • M. A. Drury, E. Daly, G.K. Davis, J.R. Delayen, C. Grenoble, W.R. Hicks, K. King, T. Plawski, T. Powers, J.P. Preble, H. Wang, M. Wiseman
    Jefferson Lab, Newport News, Virginia
  Funding: Supported by U.S. DOE Contract Nos. DE-AC05-84ER40150.

Thomas Jefferson National Accelerating Facility (Jefferson Lab) has completed production of 24 Superconducting Radio Frequency (SRF) cryomodules for the Spallation Neutron Source (SNS) superconducting linac. This includes one medium-beta (0.61) prototype, eleven medium-beta and twelve high-beta (0.81) production cryomodules. Ten medium-beta cryomodules as well as two high beta cryomodules have undergone complete operational performance testing in the Cryomodule Test Facility at Jefferson Lab. The set of tests includes measurements of maximum gradient, unloaded Q (Q0), microphonics, and response to Lorentz forces. The Qext’s of the various couplers are measured and the behavior of the higher order mode couplers is examined. The mechanical and piezo tuners are also characterized. The results of these performance tests will be discussed in this paper.

 
 
RPPE062 The Use of Integrated Electronic Data Capture and Analysis for Accelerator Construction and Commissioning: Pansophy from the SNS Towards the ILC SNS, site, feedback, monitoring 3556
 
  • J.P. Ozelis, V. Bookwalter, B.D. Madre, C.E. Reece
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by U.S. Department of Energy under contract DE-AC05-84ER40150.

Jefferson Lab has extensively used a proprietary web-based system (Pansophy) that integrates commercial database, data analysis, document archiving and retrieval, and user interface software, as a coherent knowledge management product during the construction of the cryomodules for the SNS Superconducting Linac, providing elements of process and procedure control, data capture and review, and data mining and analysis. With near real-time and potentially global access to production data, process monitoring and performance analyses could be pursued in a timely manner, providing crucial feedback. The extensibility, portability, and accessibility of Pansophy via universally available software components provide the essential features needed in any information and project management system capable of meeting the needs of future accelerator construction efforts, requiring an unprecedented level of regional and international coordination and collaboration, to which Pansophy is well suited.

 
 
RPPE063 Concepts for the JLab Ampere-Class CW Cryomodule damping, SNS, vacuum, dipole 3588
 
  • R.A. Rimmer, E. Daly, J. Henry, W.R. Hicks, J.P. Preble, M. Stirbet, H. Wang, K. Wilson, G. Wu
    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, and by The Office of Naval Research under contract to the Dept. of Energy.

We describe the concepts and developments underway at JLab as part of the program to develop a new CW cryomodule capable of transporting ampere-level beam currents in a compact FEL. Requirements include real-estate gradient of at least 10 MV/m and very strong HOM damping to push BBU thresholds up by two or more orders of magnitude compared to existing designs. Cavity shape, HOM damping, power couplers, tuners etc. are being designed and optimized for this application. Cavity considerations include a large iris for beam halo, low-RF losses, HOM frequencies and Q’s, low peak surface fields, field flatness and microphonics. Module considerations include high packing factor, low static heat leak, image current heating of beam-line components, cost and maintainability. This module is being developed for the next generation ERL based high power FELs but may be useful for other applications such as electron cooling, electron-ion colliders, industrial processing etc.

 
 
RPPP001 Commissioning and First Measurements on the CTF3 Chicane quadrupole, emittance, 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.  
 
RPPP002 RF Sources of Super-Conducting Test Facility (STF) at KEK klystron, feedback, proton, linear-collider 796
 
  • S. Fukuda, H. Hayano
    KEK, Ibaraki
  After the ITRP’s technical choice, KEK tried to seek the contribution for the international linear collider and made the plan of super-conducting test facility (STF) in KEK. The STF comprised of phase-I and phase-II; former is the plan for two years from FY2005 and aimed for the quick construction of test facility to evaluate the 4-35MV/m cavity structures and 4-45 MV/m cavity structures with a beam. Phase-II is the next plan of the test facility to extend the several 17m cryomodules. In this paper, general description of the STF is made at first, and rf source plan is shown.  
 
RPPP006 The PITZ Booster Cavity–A Prototype for the ILC Positron Injector Cavities booster, positron, coupling, emittance 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.  
 
RPPP009 Luminosity Tuning Bumps in the CLIC Main Linac luminosity, emittance, simulation, 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.

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

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

 
 
RPPP011 Different Options for Dispersion Free Steering in the CLIC Main Linac emittance, 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.

 
 
RPPP014 Multi-Bunch Simulations of the ILC for Luminosity Performance Studies simulation, luminosity, feedback, ground-motion 1368
 
  • G.R. White
    Queen Mary University of London, London
  • D. Schulte
    CERN, Geneva
  • N.J. Walker
    DESY, Hamburg
  Funding: This work is supported by the Commission of the European Communities under the 6th Framework Programme "Structuring the European Research Area", contract number RIDS-011899.

To study the luminosity performance of the International Linear Collider (ILC) with different design parameters, a simulation was constructed that tracks a multi-bunch representation of the beam from the Damping Ring extraction through to the Interaction Point. The simulation code PLACET is used to simulate the LINAC, MatMerlin is used to track through the Beam Delivery System and GUINEA-PIG for the beam-beam interaction. Included in the simulation are ground motion and wakefield effects, intra-train fast feedback and luminosity-based feedback systems. To efficiently study multiple parameters/multiple seeds, the simulation is deployed on the Queen Mary High-Throughput computing cluster at Queen Mary, University of London, where 100 simultaneous simulation seeds can be run.

 
 
RPPP019 Revisiting the Cold ILC Parameters damping, collider, luminosity, feedback 1661
 
  • H. Padamsee
    Cornell University, Ithaca, New York
  At the first ILC Workshop, discussions were underway to re-examine the parameters of the cold ILC. Using the TESLA parameters MathCad program developed in 1991, I examined several variations to explore consequences to the capital and operating costs of the linac (cryomodules, RF, & refrigerator). The cost coefficients were chosen to match the distribution of the above items in the TESLA TDR at 25 MV/m. One parameter varied is the gradient from 25 to 50 MV/m coupled with a realistic Q as well as an optimistic Q (1010). Other parameters varied are: number of bunches, spacing, and rep rate to decrease the damping ring size. Keeping all other TDR parameters the same, the optimal gradient for the realistic Q curve is about 35 MV/m, yielding a capital cost savings of 16% and a total cost savings of 9% over the nominal gradient of 25 MV/m. If however the Q remains at 1010, the optimum gradient moves to 50 MV/m where the total cost savings rise to 17.5%, and capital cost savings rise to 35%. Of course, gradients higher than 35 MV/m are extremely challenging, demanding major development efforts, such as control of Lorentz force detuning which increases as the square of the gradient.  
 
RPPP021 Multivariate Optimization of ILC Parameters luminosity, collider, emittance, linear-collider 1736
 
  • I.V. Bazarov
    Cornell University, Department of Physics, Ithaca, New York
  • H. Padamsee
    Cornell University, Ithaca, New York
  Funding: This work is supported by the NSF.

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

 
 
RPPP024 Comparison of Beam-Based Alignment Algorithms for the ILC emittance, alignment, 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.

 
 
RPPP026 Linear Accelerator Simulations with BMAD simulation, emittance, 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.

 
 
RPPP034 Multi-Stage Bunch Compressors for the International Linear Collider emittance, damping, 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 emittance, 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 emittance, 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.

 
 
RPPP049 Bunching for Shorter Damping Rings for the ILC damping, extraction, kicker, positron 3052
 
  • D.V. Neuffer
    Fermilab, Batavia, Illinois
  A variant rearrangement of the bunch trains for the ILC that enables much shorter damping rings is presented. In a particular example the ~2280 bunches are regrouped into ~450 subtrains of five adjacent bunches. These subtrains are extracted from the damping rings at ~2.2 ms intervals, obtaining the 1ms macrobunch length of the baseline TESLA collider scenario. If the baseline damping rf frequency is 325 MHz and the kicker rise and fall times are ~20 ns, a ring circumference of ~4.5km is required. Variations of the scheme could easily reduce the circumference to ~3km, and faster kickers could reduce it even further.  
 
RPPT001 The BESSY Soft X-Ray FEL User Facility photon, electron, undulator, simulation 746
 
  • D. Kraemer
    BESSY GmbH, Berlin
  Funding: Funded by Zukunftsfonds Berlin.

The user requests for an optimized 2nd generation FEL facility in the VUV to soft X-ray range demand for ultra short photon pulses (t = 20 fs) at a peak power of several GW. A high shot to shot reproducibility of the pulse shape and pulse power allowing for fs-synchronization for pump-probe experiments is feasible in a seeded FEL approach. Free selectable photon polarization and wavelength tuning is essential for any 2nd generation FEL source like the proposed BESSY-Soft X-ray FEL user facility. Freely selectable pulse repetition rates and freely selectable pulse patterns, including fast switching to different parallel operating FEL-Lines are necessary ingredients, feasible with a suitable injector in combination with a CW-superconducting linac. The status of the BESSY HGHG-FEL project will be reviewed.

 
 
RPPT006 Commissioning of TTF2 Bunch Compressor for the Femtosecond (FS) FEL Mode Operation emittance, 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 emittance, space-charge, optics, 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.  
 
RPPT014 Design and Measurements of an X-Band Accelerating Cavity for SPARC coupling, resonance, scattering, higher-order-mode 1407
 
  • D. Alesini, M. Ferrario, B. Spataro
    INFN/LNF, Frascati (Roma)
  • A. Bacci
    INFN/LASA, Segrate (MI)
  • A. Falone, M.  Migliorati, A. Mostacci, F. Palpini, L. Palumbo
    Rome University La Sapienza, Roma
  The paper presents the design of an X-band accelerating section for linearizing the longitudinal phase space in the Frascati Linac Coherent Light Source (SPARC). The structure, operating on the pi standing wave mode, is a 9 cells structure feeded by a central waveguide coupler and has been designed to obtain a 5 MV accelerating voltage. The 2D profile has been obtained using the e.m. codes SUPERFISH and OSCARD2D while the coupler has been designed using HFSS. Bead-pull measurement made on a copper prototype are illustrated and compared with the numerical results. Mechanical details of the realized prototype and RF properties of the structure as a function of the assembly characteristics are also discussed.  
 
RPPT015 Start To End Simulation for the SPARX Project emittance, 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.  
 
RPPT016 Effects of Wakefields on the Microbunching Instabilities at PAL-XFEL impedance, space-charge, synchrotron, synchrotron-radiation 1473
 
  • E.-S. Kim
    PAL, Pohang, Kyungbuk
  We present effects of the wakefields in accelerating structures of the S-band linac on the microbunching instabilties at the PAL-XFELs. Analytical calculations are performed to investigate the gains of the instabilities in the accelerator system for the PAL-XFELs.  
 
RPPT017 Wake Field Effect on the SASE Performance of PAL XFEL undulator, radiation, emittance, 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.

 
 
RPPT019 Start to End Simulations of the ERL Prototype at Daresbury Laboratory simulation, electron, wiggler, booster 1643
 
  • C. Gerth, M.A. Bowler, B.D. Muratori, H.L. Owen, N. Thompson
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • B. Faatz
    DESY, Hamburg
  • B.W.J. McNeil
    Strathclyde University, Glasgow
  Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will serve as a research and development facility for the study of beam dynamics and accelerator technology important to the design and construction of the proposed 4th Generation Light Source (4GLS) project. Two major objectives of the ERLP are the demonstration of energy recovery and of energy recovery from a beam disrupted by an FEL interaction as supplied by an infrared oscillator system. In this paper we present start-to-end simulations of the ERLP including such an FEL interaction. The beam dynamics in the high-brightness injector, which consists of a DC photocathode gun and a superconducting booster, have been modelled using the particle tracking code ASTRA. After the booster the particles have been tracked with the code GPT which includes space charge in the injector line at 8.3 MeV. The 3D code GENESIS 1.3 was used to model the FEL interaction with the electron beam at 35 MeV.  
 
RPPT020 Space Charge Effects for the ERL Prototype Injector Line at Daresbury Laboratory emittance, space-charge, dipole, 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.  
 
RPPT022 Optics for High Brightness and High Current ERL Project at BNL gun, electron, dipole, emittance 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.

 
 
RPPT024 Doubling the Intensity of an ERL Based Light Source undulator, wiggler, electron, synchrotron 1862
 
  • A. Hutton
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by the U.S. DOE under Contract No. DE-AC05-84ER40150.

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

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

 
 
RPPT026 Status of a Plan for an ERL Extension to CESR emittance, 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 electron, laser, feedback, emittance 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.

 
 
RPPT032 High Current Energy Recovery Linac at BNL electron, emittance, 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.

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

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

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

 
 
RPPT036 200 MeV Linac Upgrade for FEL gun, electron, cathode, klystron 2464
 
  • Y.G. Zhou, S. Dong, H. He, L.G. Li
    USTC/NSRL, Hefei, Anhui
  The present status of Hefei 200 MeV RF linac are given. By upgrading its present thermal cathode system into the photo cathode system and implement RF phase locked system, using Hefei 200 MeV RF linac as FEL driver is investigated.  
 
RPPT045 A Method to Calibrate Beam Position Monitor at HLS 200 MeV LINAC pick-up, simulation, impedance, injection 2896
 
  • J.-H. Li, Y. Cao, H. He, K. Jin, P. Lu, B. Sun, J. P. Wang, Y. Wang, P. Zheng
    USTC/NSRL, Hefei, Anhui
  In order to improve injection efficiency of HLS 200Mev LINAC, we redesign a new strip line beam position monitor system, which is consisted of a strip line structure and a signal processing system. We decide on an online calibration method based on beam to find out the geometry centre displacement and relative gain offset. Before the BPM testing bench has been prepared, we make a simulation based on the model accounted for all factors influencing signal amplitudes and get the calibrating results. At last, we analyze the nonlinearity effect on the calibration results.  
 
RPPT052 Analysis of Rapid Betatron Resonance Crossing resonance, betatron, acceleration, lattice 3206
 
  • S.R. Koscielniak, A. Baartman
    TRIUMF, Vancouver
  Funding: TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada.

The reduction of transverse and longitudinal cooling requirements, the increased number of beam circulations, and the reduce cost, as compared to RLAs, are arguments to adopt the linear-field FFAG as the acceleration stage of a Neutrino Factory. Because of the large range of central momenta, pm 50% delta p/p, and negative uncorrected chromaticity, the non-scaling FFAG will cross many integer and half-integer betatron resonances during the 10-20 turns acceleration. There is the expectation that if driving terms are small enough and crossing is fast enough, then there is insufficient time for the betatron amplitudes to grow. The conventional theory of resonance crossing is applied to slow acceleration, over 100s or 1000s of turns. This paper examines whether the rapid parameter changes encountered in the multi-GeV FFAGs, or few-MeV electron model, are compatible with simple theory.

 
 
RPPT060 The MuCool Test Area at Fermilab proton, shielding, radiation, target 3482
 
  • C. Johnstone, A. Bross, I. Rakhno
    Fermilab, Batavia, Illinois
  Funding: Work supported by the US Dept. of Energy under contract No. DE-AC02-76CH03000

A new experimental area designed to develop, test and verify muon ionization cooling using the 400- MeV Fermilab Linac proton beam began construction in spring, 2002. This area will be used initially for cryogenic tests of liquid-hydrogen absorbers for the MUCOOL R&D program and, later, for high-power beam tests of these absorbers and other prototype muon-cooling apparatus. The experimental scenarios being developed for muon facilities involve collection, capture, and cooling of large-emittance, high-intensity muon beams–~1013 muons at a repetition rate of 15Hz, so that conclusive tests of the apparatus require full Linac beam, or 1.6 x 1013 p at 15 Hz. To support the muon cooling facility, a new primary beamline will divert beam from the Linac to the test facility. Located southwest of Wilson Hall between the Linac berm and parking lot, implementation of the facility and associated beamline takes advantage of civil construction and resources that remain from the 400-MeV Linac Upgrade Project. The design concept for the MuCool facility is taken from an earlier proposal, but modifications to the existing proposal were necessary to accommodate high-intensity beam, cryogenics, and the increased scale of the cooling experiments.

 
 
RPPT065 Beam Loss Estimates and Control for the BNL Neutrino Facility injection, beam-losses, emittance, proton 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.

 
 
RPPT070 Status Report on the Installation of the Warm Sections for the Superconducting Linac at the SNS vacuum, SNS, quadrupole, alignment 3828
 
  • R. Kersevan, D.P. Briggs, I.E. Campisi, J.A. Crandall, D.L. Douglas, T. Hunter, P. Ladd, C. Luck, R.C. Morton, K.S. Russell, D. Stout
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, 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 and Oak Ridge.

The SNS superconducting linac (SCL) consists of 23 cryomodules (CMs), with possibly 9 additional CMs being added for future energy upgrade from 1 GeV to 1.3 GeV. A total of 32 warm sections separate the comparatively short CMs, and this allows a CM exchange within 48 hours, in order to meet demanding beam availability specifications. The 32 warm section chambers are installed between each pair of CMs, with each section containing a quadrupole doublet, beam diagnostics, and pumping. The chambers are approximately 1.6 m long, have one bellow installed at each end for alignment, and are pumped by one ion-pump. The preparation and installation of these chambers must be made under stringent clean and particulate-free conditions, in order to ensure that the performance of the SCL CMs is not compromised. This paper will discuss the development of the cleaning, preparation, and installation procedures that have been adopted for the warm sections, and the vacuum performance of this system.

 
 
RPPT071 Installation of the Spallation Neutron Source (SNS) Superconducting Linac SNS, vacuum, quadrupole, acceleration 3838
 
  • D. Stout, I.E. Campisi, F. Casagrande, R.I. Cutler, D.R. Hatfield, M.P. Howell, T. Hunter, R. Kersevan, P. Ladd, W.H. Strong
    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 (SNS) cold linac consists of 11 medium beta (0.61) and 12 high beta (0.81) superconducting RF cryomodules, 32 intersegment quadrupole magnet/diagnostics stations, 9 spool beampipes for future upgrade cryomodules, and two differential pumping stations on either side of the linac. The cryomodules and spool beampipes were designed and manufactured by Jefferson Laboratory, and the quadrupole magnets and beam position monitors were designed and furnished by Los Alamos National Laboratory. The remaining items were designed by ORNL. At present we are installing and testing the cold linac. Experience gained during installation will be presented. The performance in terms of mechanical and cryogenic systems will be described.

 
 
RPPT074 Beam Characterizations at Femtosecond Electron Beam Facility electron, cathode, acceleration, radiation 3925
 
  • S. Rimjaem, V. Jinamoon, Mr. Kangrang, K. Kusoljariyakul, J. Saisut, C. Thongbai, T. Vilaithong
    FNRF, Chiang Mai
  • M.W. Rhodes, P. Wichaisirimongkol
    IST, Chiang Mai
  • H. Wiedemann
    SLAC, Menlo Park, California
  Funding: We are grateful to the Thailand Research Fund, the National Research Council of Thailand, the Thai Royal Golden Jubilee Scholarship, the U.S. Department of Energy, and the Hansen Experimental Physics laboratory of Stanford University.

The SURIYA project at the Fast Neutron Research Facility (FNRF) has been established and is being commissioning to generate femtosecond electron pulses. Theses short pulses are produced by a system consisting of an S-band thermionic cathode RF-gun, an alpha magnet as a magnetic bunch compressor, and a linear accelerator. The characteristics of its major components and the beam characterizations as well as the preliminary experimental results will be presented and discussed.

 
 
ROPA001 XAL Application Programming Structure SNS, injection, lattice, diagnostics 79
 
  • J. Galambos, C. Chu, S.M. Cousineau, V.V. Danilov, J.G. Patton, T.A. Pelaia, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee
  • C.K. Allen
    LANL, Los Alamos, New Mexico
  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.

XAL is an application programming framework used at the Spallation Neutron Source (SNS) project in Oak Ridge. It is written in Java, and provides users with a hierarchal view of the accelerator. Features include database configuration of the accelerator structure, an online envelope model that is configurable from design or live machine values, an application framework for quick-start GUI development, a scripting interface for algorithm development, and a common toolkit for shared resources. To date, about 25 applications have been written, many of which are used extensively in the SNS beam commissioning activities. The XAL framework and example applications will be discussed.

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

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

 
 
ROPC001 SNS Warm Linac Commissioning Results rfq, SNS, quadrupole, emittance 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.

 
 
ROPC002 J-PARC Commissioning Results injection, proton, synchrotron, rfq 220
 
  • K. Hasegawa
    JAERI, Ibaraki-ken
  The J-PARC (Japan Proton Accelerator Research Complex)comprises a 400-MeV linac, a 3-GeV rapid-cycling synchrotron (RCS), a 50-GeV main ring synchrotron (MR) and experimental facilities. A peak current of 30 mA was accelerated up to 20 MeV of the DTL beam commissioning at the KEK site. The buildings and conventional facilities will be completed in succession in the Japanese Fiscal Year 2005, when the installation of the accelerator components will be actually started at Tokai site. The beam commissioning of the 181 MeV linac will be started in September, 2006, followed by the RCS and MR beam commissioning. To achieve the high beam power with low beam loss, the J-PARC accelerators are based on many newly developed technologies; pi-mode stabilizing loops in the RFQ, RF choppers in the medium energy beam transport, magnetic alloy loaded RF cavities in the synchrotrons, etc. The recent results of the developments of these new technologies, the present construction status and the commissioning schedule will be presented.  
 
ROPC005 RIA Post Accelerator Design ion, rfq, emittance, 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.  
 
ROPC007 Status of the Proton Engineering Frontier Project proton, rfq, klystron, beam-transport 576
 
  • B.H. Choi
    KAERI, Daejon
  Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government.

The Proton Engineering Frontier Project (PEFP) approved and launched by the Korean government in July 2002 includes a 100MeV proton linear accelerator development and a program for its utilization. The first phase of the project, running from 2002 to 2005, was the design of a 100MeV proton linear accelerator and a part of development to 20 MeV. This consists of a 50 keV proton injector, a 3 MeV radio frequency quadrupole (RFQ), and a 20MeV drift tube linac (DTL). The 50 keV injector and the 3 MeV RFQ has been installed and tested, and the 20 MeV DTL is being assembled and tuned for beam tests. At the same time, the utilization programs using the proton beam have been planned, and some are now under way. The status and progress of the project are reported in detail.

 
 
ROPC010 Testing, Installation, Commissioning and First Operation of the ISIS RFQ Pre-Injector Upgrade rfq, vacuum, emittance, 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.  
 
FOAC005 Reliability and Availability Studies in the RIA Linac Driver simulation, controls, site, power-supply 443
 
  • E.S. Lessner, P.N. Ostroumov
    ANL, Argonne, Illinois
  Funding: Work supported by the U. S. Department of Energy under contract W-31-109-ENG-38.

The RIA facility will include various complex systems and must provide radioactive beams to many users simultaneously. The availability of radioactive beams for most experiments at the fully-commissioned facility should be as high as possible within design cost limitations. To make a realistic estimate of the achievable reliability a detailed analysis is required. The RIA driver linac is a complex machine containing a large number of SC resonators and capable of accelerating multiple-charge-state beams. At the pre-CDR stage of the design it is essential to identify critical facility subsystem failures that can prevent the driver linac from operating. The reliability and availability of the driver linac are studied using expert information and data from operating machines such as ATLAS, APS, JLab, and LANL. Availability studies are performed with a Monte-Carlo simulation code previously applied to availability assessments of the NLC facility [http://www.slac.stanford.edu/xorg/accelops/Full/LCoptsfull] and the results used to identify subsystem failures that affect most the availability and reliability of the RIA driver, and guide design iterations and component specifications to address identified problems.

*J.A. Nolen, Nucl. Phys. A. 734 (2004) 661.

 
 
FPAE019 Booster 6-GeV Study booster, acceleration, proton, beam-losses 1637
 
  • X. Yang, C.M. Ankenbrandt, J.R. Lackey, R.D. Padilla, W. Pellico
    Fermilab, Batavia, Illinois
  • J. Norem
    ANL, Argonne, Illinois
  Funding: Fermi National Accelerator Laboratory, Accelerator Division, Proton Source Department.

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

 
 
FPAE027 Status of the ISAC-II Accelerator at TRIUMF acceleration, vacuum, ion, heavy-ion 2003
 
  • R.E. Laxdal, W. Andersson, P. Bricault, I. Bylinskii, K. Fong, M. Marchetto, A.K. Mitra, R.L. Poirier, W.R. Rawnsley, P. Schmor, I. Sekachev, G. Stanford, G.M. Stinson, V. Zviagintsev
    TRIUMF, Vancouver
  A heavy ion superconducting linac is being installed at TRIUMF to increase the final energy of radioactive beams at ISAC. A first stage of 20MV consisting of five medium beta cryomodules each with four quarter wave bulk niobium cavities and a superconducting solenoid is being installed with initial beam commissioning scheduled for Dec. 2005. The initial cryomodule has met cryogenic and rf performance specifications. In addition we have demonstrated acceleration of alpha particles in an off-line test. A 500W refrigerator system has been installed and commissioned in Jan. 2005 with cold distribution due for commissioning in Sept. 2005. A transfer beamline from the ISAC accelerator and beam transport to a first experimental station are being installed. The status of the project will be presented.  
 
FPAE028 Design of the High Intensity Exotic Beams SPIRAL 2 Project ion, rfq, quadrupole, beam-losses 2044
 
  • A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • M.H. Moscatello
    GANIL, Caen
  The SPIRAL 2 facility will be able to deliver stable heavy ion beams and deuteron beams at very high intensity, allowing to produce and accelerate light and heavy rare ion beams. The driver will accelerate a 5 mA deuteron beam up to 20 MeV/u and also q/A=1/3 heavy ions up to 14.5 MeV/u. The injector consist of the ion sources, a 4-vane RFQ and the low and medium beam transfer lines. It is followed by an independently phased superconducting linac with compact cryostats separated with warm focusing sections. The overall design and results of simulations with combined errors, the results of tests of prototypes for the most critical components are presented.  
 
FPAE033 Operational Availability of the SNS During Commissioning SNS, ion-source, ion, diagnostics 2289
 
  • G.W. Dodson, T.L. Williams
    ORNL, Oak Ridge, Tennessee
  Funding: This work was supported by SNS through UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The SNS Front End, Drift Tube Linac and most of the Coupled Cavity Linac have been operated during commissioning. Operating statistics were taken and used by system owners to target developments to improve accelerator availability. This progression will be shown along with the overall availability goals of the SNS and a RAM calculation showing the system and subsystem availability required to meet these goals.

 
 
FPAE040 First Operation of PIAVE, the Heavy Ion Injector Based on Superconducting RFQ's vacuum, ion, ion-source, acceleration 2621
 
  • G. Bisoffi, G. Bassato, A. Battistella, G.P. Bezzon, l. Boscagli, A. Calore, S. Canella, D. Carlucci, F. Chiurlotto, M. Comunian, M. De Lazzari, A. Facco, E. Fagotti, A. Lombardi, P. Modanese, M.F. Moisio, A. Pisent, M. Poggi, A.M. Porcellato, S. Stark
    INFN/LNL, Legnaro, Padova
  The Positive Ion Accelerator for low-Velocity Ions (PIAVE), based on superconducting RFQ's (SRFQ's), has been completed in fall 2004 with the first acceleration of beams from the ECR ion source. Superconducting RFQ's were used, for the first time, for beam acceleration on a user-oriented accelerator complex. A general status of the injector performances is given: it includes, besides the SRFQ's, eight superconducting (SC) QWR's and three bunchers; the beam is received from an ECR source on a HV platform and is delivered, through the SC accelerator ALPI, to nuclear physics experimental apparatuses. The paper emphasizes, in particular, the technological challenges related to the operation of the SC cavities, the cryogenics, control, diagnostics and vacuum systems.  
 
FPAE042 Beam Commissioning of the Superconducting RFQs of the New LNL Injector PIAVE rfq, ion, emittance, 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 quadrupole, monitoring, coupling, emittance 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.  
 
FPAE045 Design of the PEFP MEBT proton, quadrupole, rfq, extraction 2881
 
  • J.-H. Jang, Y.-S. Cho, Y.-H. Kim, H.-J. Kwon
    KAERI, Daejon
  Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government.

A MEBT system of the PEFP(Proton Engineering Frontier Project) has to be installed after the 20MeV DTL where the beam will be supplied to the user group through a beam extraction system. Until now we don't have a plan to put in some matching devices between the RFQ and 20MeV DTL except using the four quadrupole magnets in the first DTL tank as transverse matching tools. The MEBT plays the key role to match the 20MeV output beam into the next accelerator in the longitudinal direction as well as transverse one. This report shows the basic concept and the design status of the system.

 
 
FPAE049 Development and Implementation of ?T Procedure for the SNS Linac SNS, monitoring, simulation, beam-loading 3064
 
  • A. Feschenko, S. Bragin, Y. Kiselev, L.V. Kravchuk, O. Volodkevich
    RAS/INR, Moscow
  • A.V. Aleksandrov, J. Galambos, S. Henderson, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The ?t procedure is a time of flight technique for setting the phases and amplitudes of accelerating fields in a multi-cavity linac. It was initially proposed and developed for the LAMPF linac in the early seventies and since then has been used in several accelerators. The SNS linac includes four CCL modules (Side Coupled Structure) operating at 805 MHz for the energy range from 86.8 MeV up to 185.6 MeV. The ?t procedure has been implemented for the SNS CCL linac and was used for its initial beam commissioning. Brief theory of the procedure, the results of the design parameter calculations and the experimental results of phase and amplitude setpoints are presented and discussed.

 
 
FPAE050 Injector Linac for the BNL Super Neutrino Beam Project quadrupole, SNS, proton, insertion 3129
 
  • D. Raparia, J.G. Alessi, A. Ruggiero, W.-T. Weng
    BNL, Upton, Long Island, New York
  Funding: This work was performed under the auspices of the U.S. DOE, Contract No. DE-AC02-98H10886.

BNL plans to upgrade the AGS proton beam from the current 0.14 MW to higher than 1.0 MW and beyond for such a neutrino facility. We have examined possible upgrades to the AGS complex that would meet the requirements of the proton beam for a 1.0 MW neutrino superbeam facility. We are proposing to replace part of the existing 200 MeV linac with coupled cavity structure from 116 MeV to 400 MeV and then add additional 1.1 GeV superconducting linac to reach a final energy of 1.5 GeV for direct H- injection into the AGS. We will present possible choices for the upgrade and our choice and its design.

 
 
FPAE052 The LENS 7 MeV, 10 mA Proton Linac proton, rfq, target, ion 3200
 
  • V.P. Derenchuk, D.V. Baxter, A. Bogdanov, W.P. Jones, T. Rinckel, K. A. Solberg
    IUCF, Bloomington, Indiana
  Funding: This work has been supported by the National Science Foundation under grants DMR-0220560, and DMR-0320627, by the Indiana 21st Century Science and Technology Fund, and by the Department of Defense.

The Indiana University Cyclotron Facility (IUCF) has constructed and placed in operation a Low Energy Neutron Source (LENS) using a 10 mA, 7 MeV proton beam incident on a beryllium target. The proton delivery system (PDS) consists of a 25 keV proton injector, an AccSys Technology, Inc. PL7 Linac* and a beam transport line with non-linear beam spreading.** The accelerator and beamline equipment used in this construction are refurbished and upgraded components from the IUCF CIS/Cooler synchrotron*** facility. After commissioning the beam current at 7 MeV will be 10 mA with a pulse width of up to 300 μs and > 1% duty factor. The PDS was constructed and commissioning started in 2004. First operating results will be described.

*D.L. Friesel and W. Hunt, Linac98, pp61-63. **W.P. Jones, et. al., "Non-Linear Beam Transport System for the LENS 7 MeV Proton Beam," this proceedings. ***D.L. Friesel, et. al., EPAC2000, pp. 539-541.

 
 
FPAE054 Front End Design of a Multi-GeV H-minus Linac focusing, rfq, lattice, emittance 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 rfq, focusing, emittance, 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.

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

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

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

 
 
FPAE057 Beam Dynamics Studies and Beam Quality in the SNS Normal-Conducting Linac emittance, 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.

 
 
FPAE058 Spallation Neutron Source Superconducting Linac Commissioning Algorithms SNS, simulation, Spallation-Neutron-Source, resonance 3423
 
  • S. Henderson, I.E. Campisi, J. Galambos, D.-O. Jeon, Y. Zhang
    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.

We describe the techniques which will be employed for establishing RF and quadrupole setpoints in the SNS superconducting linac. The longitudinal tuneup will be accomplished using phase-scan methods, as well as a technique that makes use of the beam induced field in the unpowered cavity.* The scheme for managing the RF and quadrupole setpoints to achieve a given energy profile will be described.

*L. Young, Proc. PAC 2001, p. 572.

 
 
FPAE059 Transverse Matching Techniques for the SNS Linac emittance, 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 simulation, emittance, 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.  
 
FPAE063 Enhancements of Machine Reliability and Beam Quality in SPring-8 Linac for Top-Up Injection into Two Storage Rings klystron, injection, synchrotron, feedback 3585
 
  • H. Hanaki, T. Asaka, H. Dewa, T. Kobayashi, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida
    JASRI/SPring-8, Hyogo
  SPring-8 has started its top-up operation from May 2004 in order to feed constant photon fluxes to users. The SPring-8 linac has been improved to realize stable and uninterrupted top-up injection into the SPring-8 storage ring and the NewSUBARU storage ring. The beam energy instability of 0.01% rms had been achieved by the following stabilization: RF amplitude and phase stabilization, synchronization of beam timing and linac's 2856 MHz RF and introduction of an energy compensation system (ECS). Feedback controls of steering magnets compensate long-term variation of beam trajectories at ends of beam transport lines. The presentation will include also recent improvements.  
 
FPAE067 Present Design and Calculation for the Injection-Dump Line of the RCS at J-PARC injection, beam-losses, quadrupole, emittance 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.  
 
FPAT002 Automatic Steering for the CTF3 Linear Accelerator simulation, dipole, focusing, lattice 814
 
  • R.D. Lifshitz
    Technion, Haifa
  • 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)

A system for automatic beam steering has been implemented at the CTF3 linear accelerator. Beam position readings are logged while corrector magnet strengths are scanned over a given range, thus giving a steering response measurement. Assuming linearity, a response matrix is constructed and used to automatically optimize the beam trajectory along the linac. Using a simple BPM-reading minimization for trajectory correction, this system has been tested in the 2004 CTF3 summer run. Although not in routine operation, it has already proved useful as a tool for the machine setup and operation. In this paper, the automatic steering system for the CTF3 linac is introduced, trajectory correction results are presented, and the agreement with a computer model of the machine is discussed.

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

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

 
 
FPAT016 PASTA – An RF Phase and Amplitude Scan and Tuning Application RF-structure, SNS, Spallation-Neutron-Source, controls 1491
 
  • J. Galambos, A.V. Aleksandrov, C. Deibele, S. Henderson
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

To assist the beam commissioning in the Spallation Neutron Source (SNS) linac, a general purpose RF tuning application has been written to help set RF phase and amplitude. It follows the signature matching procedure described in Ref.* The method involves varying an upstream Rf cavity amplitude and phase settings and comparing the measured downstream beam phase responses to model predictions. The model input for cavity phase and amplitude calibration and for the beam energy are varied to best match observations. This scheme has advantages over other RF tuning techniques of not requiring intercepting devices (e.g. Faraday Cups), and not being restricted to a small linear response regime near the design values. The application developed here is general and can be applied to different RF structure types in the SNS linac. Example applications in the SNS Drift Tube Linac (DTL) and Coupled Cavity Linac (CCL) structures will be shown.

*T.L. Owens, M.B. Popovic, E.S. McCrory, C.W. Schmidt, L. J. Allen, "Phase Scan Signature Matching for Linac Tuning," Particle Accelerators, 1994 Vol 98, p. 169.

 
 
FPAT020 A Fast Chopper for Intensity Adjustment of Heavy-Ion Beams impedance, ion, heavy-ion, vacuum 1692
 
  • A.V. Novikov-Borodin, V.A. Kutuzov
    RAS/INR, Moscow
  • P.N. Ostroumov
    ANL, Argonne, Illinois
  Funding: CRDF Grant.

There are several heavy-ion linac projects being developed worldwide. For example, the Rare Isotope Accelerator Facility [J.A. Nolen, Nucl. Phys. A. 734 (2004) 661] currently being designed in the U.S. will use both heavy-ion and light ion beams to produce radionuclides via the fragmentation and spallation reactions, respectively. With simultaneous beam delivery to more than one target independent adjustment of relative beam intensities is essential. A fast traveling wave chopper can be used to modulate cw beam intensity at low energy ~200 keV/u. Such a device should have high frequency characteristics at high power level. By increasing the wave impedance of the traveling wave structure up to 200 Ohm one can reduce power requirements to the fast voltage pulser. Several design options of the high-impedance structure are discussed.

 
 
FPAT036 An Induction Linac Test Stand induction, pulsed-power, diagnostics, electron 2455
 
  • W. J. DeHope, D.A. Goerz, R. Kihara, M.M. Ong, G.E. Vogtlin, J.M. Zentler
    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. 7405-Eng-48.

A single-cell test stand has been constructed to facilitate study and guide improvements of the induction electron linac at the FXR radiographic facility at LLNL.* This paper will discuss how modifications in pulse compression and shaping, pulse power transmission, initial ferrite state, and accelerator cell loading have been performed on the test stand and can be applied to the entire accelerator. Some of the specialized diagnostics being used will be described. Finally, the paper will discuss how computer modeling and judicious timing control can be used to optimize accelerator performance by making only selective changes that can be accomplished at minimal cost.

*"Test Stand for Linear Induction Accelerator Optimization," Ong et al., Pulsed Power Conference, June 16, 2003, Dallas TX.

 
 
FPAT046 RF Control System for the DESY VUV-FEL Linac feedback, diagnostics, electron, klystron 2899
 
  • V. Ayvazyan, G.M. Petrosyan, K. Rehlich, S. Simrock, P. Vetrov
    DESY, Hamburg
  In the RF system for the Vacuum Ultraviolet Free Electron Laser (VUV-FEL) Linac each klystron supplies RF power to up to 32 cavities. The superconducting cavities are operated in pulsed mode and high accelerating gradients close to the performance limit. The RF control of the cavity fields to the level of 1·10-4 for amplitude and 0.1 degree for phase however presents a significant technical challenge due to the narrow bandwidth of the cavities which results in high sensitivity to perturbations of the resonance frequency by mechanical vibrations (microphonics) and Lorentz force detuning. A digital RF control system has been developed for the VUV-FEL which will demonstrate the required control performance. Presently the Linac is being commissioned, and this effort provides the first full integrated test in the accelerator, including cryogenics, RF, beam transport, and beam diagnostics. The RF control system design and objectives are discussed and compared to the measured performance during the first stage of the VUV-FEL Linac - TESLA Test Facility. Hardware/software design and operational challenges experienced for RF control are presented.  
 
FPAT047 Control System of 3 GeV Rapid Cycling Synchrotron at J-PARC simulation, power-supply, beam-losses, monitoring 2968
 
  • H. Takahashi, Y. Kato, M. Kawase, H. Sako
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • Y. Ito
    Total Saport System Corp., Naka-gun, Ibaraki
  • H. Sakaki
    JAERI/LINAC, Ibaraki-ken
  • M. Sugimoto
    Mitsubishi Electric Control Software Corp, Kobe
  • H. Yoshikawa
    JAERI, Ibaraki-ken
  Funding: Japan Society for the Promotion of Science (JSPS).

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

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

 
 
FPAT050 Improvement RF Control System for the 20 Mev Proton Linac of PEFP rfq, proton, feedback, radio-frequency 3100
 
  • J.C. Yoon, J. Choi, H.-S. Kang, J.-W. Lee
    PAL, Pohang, Kyungbuk
  Funding: EPICS, Control, LLRF.

This paper presents the RF control system for Korea Multi-purpose Accelerator Complex (KOMAC). KAERI (Korea Atomic Energy Research Institute) has been performing the project named KOMAC. As the 3nd phase of the project, 20MeV proton accelerating structure is under development. The new design is based on the use of VME based Multi-function modules connected to the specific low level RF Controllers(LLRF) via distributed I/O modules and Serial communication modules. The control system was based on EPICS (Experimental Physics and Industrial Control System) from the end of 2004. Installation and commissioning of the RF module is scheduled on 2005. Control system to integrated the RF System to the KOMAC control system is implemented. Hardware, software and various applications are upgrade to support the operation of RF Control system. In this paper, We describe control structure and scheme of the current RF Control System and upgraded one.

 
 
FPAT051 A New Timing System for the Duke Booster and Storage Ring booster, injection, storage-ring, electron 3159
 
  • G.Y. Kurkin
    BINP SB RAS, Novosibirsk
  • S.M. Hartman, S. Mikhailov, Y.K. Wu
    DU/FEL, Durham, North Carolina
  • I.P. Pinayev
    BNL, Upton, Long Island, New York
  Funding: AFOSR MFEL grant number is F49620-001-0370, HIGS Upgrade DOE grant number is DE-FG02-01ER41175.

A dedicated booster synchrotron is being constructed at the Duke FEL Laboratory to provide full energy injection into the main electron storage ring. A new timing system has been developed to coordinate the injection of electron bunches from the linac to the booster, the ramping of energy in the booster, and extraction of bunches into the main ring. The timing system will allow the extraction of any bunch in the booster into any selected bucket in the main ring to provide top-off injection for any of the various operational bunch patterns of the main ring. A new master oscillator has also been developed for the RF system of the booster. The oscillator may be tuned independently or phase-locked to the master oscillator of the main ring. The issues of the soft phase locking process of the new master oscillator are discussed. The timing system and new oscillator have been fabricated and tested and are ready for operation.

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

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

allison@jlab.org

 
 
FPAT067 The Design Performance of the Integrated Spallation Neutron Source Vacuum Control System vacuum, SNS, instrumentation, Spallation-Neutron-Source 3730
 
  • J.Y. Tang, J.A. Crandall, P. Ladd, D.C. Williams
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source vacuum control systems have been developed within a collaboration of Lawrence Berkeley National Laboratory(LBNL), Los Alamos National Laboratory(LANL), Thomas Jefferson National Accelerator Facility(TJNAF), and Brookhaven National Laboratory(BNL). Each participating lab is responsible for a different section of the machine. Although a great deal of effort has been made to standardize vacuum instrumentation components and the global control system interfaces, the varied requirements of the different sections of the machine made horizontal integration of the individual vacuum control systems both interesting and challenging. To support commissioning, the SNS control system team and the vacuum group developed a set of test strategies and the interlock schemes that allowed horizontal vacuum system integration to be effectively achieved. The design of the vacuum control interlock scheme developed will be presented together with the results of performance measurements made on these schemes. In addition, the experience and performance of an industrial Ethernet with real-time control used in this application will be discussed.

SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

 
 
FPAT068 Spallation Neutron Source Drift Tube Linac Resonance Control Cooling System Modeling resonance, feedback, SNS, Spallation-Neutron-Source 3754
 
  • J.Y. Tang, A.V. Aleksandrov, M.M. Champion, P.E. Gibson, J.P. Schubert
    ORNL, Oak Ridge, Tennessee
  • A. Feschenko, Y. Kiselev, A.S. Kovalishin, L.V. Kravchuk, A.I. Kvasha
    RAS/INR, Moscow
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The Resonance Control Cooling System (RCCS) for the warm linac of the Spallation Neutron Source was designed by Los Alamos National Laboratory. The primary design focus was on water cooling of individual component contributions. The sizing the RCCS water skid was accomplished by means of a specially created SINDA/FLUINT model tailored to these system requirements. A new model was developed in Matlab Simulink and incorporates actual operational values and control valve interactions. Included is the dependence of RF input power on system operation, cavity detuning values during transients, time delays that result from water flows through the heat exchanger, the dynamic process of water warm-up in the cooling system due to dissipated RF power on the cavity surface, differing contributions on the cavity detuning due to drift tube and wall heating, and a dynamic model of the heat exchanger with characteristics in close agreement to the real unit. Because of the Matlab Simulink model, investigation of a wide range of operating issues during both transient and steady state operation is now possible. Results of the DTL RCCS modeling are presented

 
 
FPAT071 Timing System for J-PARC synchrotron, proton, power-supply, target 3853
 
  • F. Tamura
    JAERI/LINAC, Ibaraki-ken
  • J.C. Chiba, T. Katoh, M. Yoshii
    KEK, Ibaraki
  J-PARC has three accelerators running at the different repetition rates; a 400-MeV linac (50Hz), a 3-GeV rapid cycling synchrotron (RCS, 25Hz), and a 50-GeV synchrotron (MR). The linac and the RCS deliver the beam pluses to the different destinations in each cycle. The destinations are scheduled according to the machine operations. We define two kinds of timing, "scheduled timing" and "synchronization timing" so that the accelerators are operated with proper timing and the beam pulses are transported to the experimental facilities or the next accelerators. The J-PARC complex requires a stable and precise timing system. The system is based on a master clock generated by a synthesizer and the triggers are operated independently of the AC-line frequency. We describe the design of the J-PARC timing system and their configuration, and also present the hardware details.  
 
FPAT072 The Status of HLS Control System photon, power-supply, storage-ring, feedback 3862
 
  • G. Liu, X. Bao, C. Li, W. Li, J. Wang, Xie. Xie, K. Xuan
    USTC/NSRL, Hefei, Anhui
  • J. Li
    DU/FEL, Durham, North Carolina
  HLS (Hefei Light Source) at NSRL (National Synchrotron Radiation Lab) consists of three parts: 200Mev Linac, transport line and 800Mev storage ring. The control system was upgraded based on EPICS (Experimental Physics and Industrial Control system) from 1999 to 2004. This paper will cover the experience of using PC-based hardware under EPICS, data archiving, and some high level tools for physics and operation use.  
 
FPAT076 PC-LabView Based Control System in SAGA-LS power-supply, vacuum, storage-ring, synchrotron 3976
 
  • H. Ohgaki
    Kyoto IAE, Kyoto
  • Y. Iwasaki, S. Koda, Y. Takabayashi, T. Tomimasu, K. Yoshida
    Saga Synchrotron Light Source, Industry Promotion Division, Saga City
  • H. Toyokawa
    AIST, Ibaraki
  A control system for SAGA Synchrotron Light Source (SAGA-LS) has been constructed. SAGA-LS is a small-medium size light source and is run by local government, which means there are a few number of staff in the laboratory. Thus the control system must be simple and robust, while inexpensive, easy to develop and maintain. The basic ideas of the system are 1) using PCs to build a low cost control system, 2) using off-shelf devices, FieldPoint (National Instrument) and PLCs, (FA-M3, Yokogawa), for robust and replaceable system, 3) using LabView for a quick in-house system development, 4) using channel access protocol between server and client to transparent from regular EPICS utilities, 5) using ActiveX CA to emulate the CA protocol. About 1,000 PVs are employed to control the magnet power supplies, the RF control sub-system, vacuum monitors, BPM data and several LCW data. The system has been operated and tuned at the beginning of the commissioning, spring 2004. MySQL database system also archives data to assist daily operation and to display the trend chart of the machine. The database applications developed by LabView, too.  
 
FPAT085 The TAO Accelerator Simulation Program quadrupole, simulation, damping, lattice 4159
 
  • D. Sagan
    Cornell University, Department of Physics, Ithaca, New York
  • J.C. Smith
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: NSF and DOE.

A new accelerator design and analysis simulation environment based on the BMAD relativistic charged particle dynamics library is in development at Cornell University. Called TAO (Tool for Accelerator Optimization), it is a machine independent program that implements the essential ingredients needed to solve simulation problems. This includes the ability to: 1. Design lattices subject to constraints, 2. Simulate errors and changes in machine parameters, and 3. Simulate machine commissioning including simulating data measurement and correction. TAO is designed to be easily customizable so that extending it to solve new and different problems is straight forward. The capability to simultaneously model multiple accelerator lattices, both linacs and storage rings, and injection from one lattice to another allows for the design and commissioning of large multi stage accelerators. It can also simultaneously model multiple configurations of a single lattice. Single particle, particle beam and macroparticle tracking is implemented. Use of TAO with both the International Linear Collider and the Cornell Energy Recovery Linac are provided as examples.

 
 
FPAT086 Lucretia: A Matlab-Based Toolbox for the Modeling and Simulation of Single-Pass Electron Beam Transport Systems simulation, lattice, klystron, electron 4197
 
  • P. Tenenbaum
    SLAC, Menlo Park, California
  We report on Lucretia, a new simulation tool for the study of single-pass electron beam transport systems. Lucretia supports a combination of analytic and tracking techniques to model the tuning and operation of bunch compressors, linear accelerators, and beam delivery systems of linear colliders and linac-driven Free Electron Laser (FEL) facilities. Extensive use of Matlab scripting, graphics, and numerical capabilities maximize the flexibility of the system, and emphasis has been placed on representing and preserving the fixed relationships between elements (common girders, power supplies, etc.) which must be respected in the design of tuning algorithms. An overview of the code organization, some simple examples, and plans for future development are discussed.  
 
FPAT088 Advanced Beam-Dynamics Simulation Tools for RIA simulation, rfq, beam-losses, acceleration 4218
 
  • R.W. Garnett, J.A. Billen, T.P. Wangler
    LANL, Los Alamos, New Mexico
  • K.R. Crandall
    TechSource, Santa Fe, New Mexico
  • P.N. Ostroumov
    ANL, Argonne, Illinois
  • J. Qiang, R.D. Ryne
    LBNL, Berkeley, California
  • R.C. York, Q. Zhao
    NSCL, East Lansing, Michigan
  Funding: U.S. Department of Energy Contract W-7405-ENG-36.

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

 
 
FPAT091 LiTrack: A Fast Longitudinal Phase Space Tracking Code with Graphical User Interface focusing, acceleration, RF-structure, electron 4266
 
  • P. Emma, K.L.F. Bane
    SLAC, Menlo Park, California
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

Many linear accelerators, such as linac-based light sources and linear colliders, apply longitudinal phase space manipulations in their design, including electron bunch compression and wakefield-induced energy spread control. Several computer codes handle such issues, but most require detailed information on the transverse focusing lattice. In fact, in most linear accelerators, the transverse distributions do not significantly affect the longitudinal, and can be ignored initially. This allows the use of a fast 2D code to study longitudinal aspects without time-consuming considerations of the transverse focusing. LiTrack is based on a 15-year old code (same name) originally written by one of us (KB), which is now a MATLAB-based code with additional features, such as a graphical user interface and output plotting. The single-bunch tracking includes RF acceleration, bunch compression to 3rd order, geometric and resistive wakefields, aperture limits, synchrotron radiation, and flexible output plotting. The code was used to design both the LCLS and the SPPS projects at SLAC and typically runs in <1 minute. We describe the features, show some examples, and provide access to the code.

 
 
FOAA001 New Technology in Hydrogen Absorbers for Muon Cooling Channels emittance, simulation, 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.

 
 
FOAA002 Technological Improvements in the DARHT II Accelerator Cells vacuum, cathode, induction, electron 169
 
  • B.A. Prichard, R.J. Briggs
    SAIC, Los Alamos, New Mexico
  • J. Barraza, M. Kang, K. Nielsen
    LANL, Los Alamos, New Mexico
  • F.M. Bieniosek, K. Chow, W.M. Fawley, E. Henestroza, L. R. Reginato, W. Waldron
    LBNL, Berkeley, California
  • T.E. Genoni, T.P. Hughes
    ATK-MR, Albuquerque, New Mexico
  Funding: This work was supported by the U.S. National Nuclear Security Agency and the U.S. Department of Energy under contract W-7405-ENG-36.

DARHT employs two perpendicular electron Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. The second axis, DARHT II, features an 18 MeV, 2-kA, 2-microsecond accelerator. DARHT II accelerator cells have undergone a series of test and modeling efforts to fully understand their sub par performance. These R&D efforts have led to a better understanding of Linear Induction Accelerator physics for the unique DARHT II design. Specific improvements have been identified and tested. Improvements in the cell oil region, the cell vacuum region, and the PFNs have been implemented in the prototype units that have doubled the cell’s performance. A series of prototype acceptance test are underway on a number of prototype units to demonstrate that the required cell lifetime is met at the improved performance levels. Early acceptance tests indicate that the lifetime requirements are being exceeded. The shortcomings of the previous design are summarized. The improvements to the original design, their resultant improvement in performance, and various test results are included. The final acceptance test results will also be included.

 
 
FOAA005 Mechanical Vibration Measurements on TTF Cryomodules monitoring, instrumentation, vacuum, quadrupole 434
 
  • A. Bosotti, C. Pagani, R. Paparella, P. Pierini, D. Sertore
    INFN/LASA, Segrate (MI)
  • R. De Monte, M. Ferianis
    ELETTRA, Basovizza, Trieste
  • R. Lange
    DESY, Hamburg
  Few of the TTF cryomodules have been equipped with Wire Position Monitors (WPM) for the on line monitoring of cold mass movements during cool-down, warm-up and operation. Each sensor can be used as a detector for mechanical vibrations of the cryostat. A Digital Receiver board is used to sample and analyze with high frequency resolution, the WPM picked up signals, looking to its amplitude modulation in the microphonic frequency range. Here we review and analyze the data and the vibration spectra taken during operation of the TTF cryomodules # 4 and #5.  
 
FOAA006 Digital Low-Level RF Controls for Future Superconducting Linear Colliders feedback, klystron, resonance, collider 515
 
  • S. Simrock
    DESY, Hamburg
  The requirements for RF Control Systems of Superconducting Linear Colliders are not only defined in terms of the quality of field control but also with respect to operability, availability, and maintainability of the RF System, and the interfaces to other subsystems. The field control of the vector-sum of many cavities driven by one klystron in pulsed mode at high gradients is a challenging task since severe Lorentz force detuning, microphonics and beam induced field errors must be suppressed by several orders of magnitude. This is accomplished by a combination of local and global feedback and feedforward control. Sensors monitor individual cavity probe signals, and forward and reflected wave as well as the beam properties including beam energy and phase while actuators control the incident wave of the klystron and individual cavity resonance frequencies. The operability of a large llrf system requires a high degree of automation while the high availability requires robust algorithms, redundancy, and extremely reliable hardware. The maintenance of the llrf demands sophisticated on-line diagnostics for the llrf subsystems to minimize downtime.  
 
FOAA008 Superconducting RF Development at Nuclear Science Centre vacuum, electron, ion, coupling 625
 
  • A. Roy
    NSC, New Delhi
  Funding: Nuclear Science Centre, New Delhi, India.

A Superconducting Linac is being installed as a booster for the 15 UD Pelletron accelerator at Nuclear Science Centre (NSC). The accelerating structure for this linac is a Nb QWR cavity, designed and fabricated as a joint collaboration between NSC and ANL, USA. Initial cavities required for the first linac module were fabricated at ANL. For fabrication of cavities required for future modules a Superconducting Resonator Fabrication Facility has been set up at NSC. Three quarter wave resonator (QWR) cavities have been fabricated using the in-house facility. This facility has been used for repairs on the resonators which sprung leaks. Fabrication of fifteen resonators for the second and third linac modules is under progress. Eight resonators along with a superconducting solenoid has been installed in the first linac cryostat and tested for energy gain with a pulsed beam of 90 MeV Si from the Pelletron. Acceleration of the ions to 96 MeV was measured downstream and beam transmission through the linac was measured to be ~ 100%.

 
 
FOAA009 SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature vacuum, pulsed-power, site, accumulation 665
 
  • R.A. Rimmer, J. F. Benesch, J.P. Preble, C.E. Reece
    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.

In September 2003, in the wake of Hurricane Isabel, JLab was without power for four days after a tree fell on the main power lines feeding the site. This was long enough to lose insulating vacuum in the cryomodules and cryogenic systems resulting in the whole accelerator warming up and the total loss of the liquid helium inventory. This thermal cycle stressed many of the cryomodule components causing several cavities to become inoperable due to helium to vacuum leaks. At the same time the thermal cycle released years of adsorbed gas from the cold surfaces. Over the next days and weeks this gas was pumped away, the insulating vacuum was restored and the machine was cooled back down and re-commissioned. In a testament to the robustness of SRF technology, only a small loss in energy capability was apparent, although individual cavities had quite different field-emission characteristics compared to before the event. In Summer 2004 a section of the machine was again cycled to room temperature during the long maintenance shutdown. We report on the overall SRF performance of the machine after these major disturbances and on efforts to characterize and optimize the new behavior for high-energy running.

 
 
FOAA010 Full Characterization at Low Temperature of Piezoelectric Actuators Used for SRF Cavities Active Tuning vacuum, proton, radiation, electromagnetic-fields 728
 
  • M. Fouaidy, S. Blivet, F. Chatelet, N. Hammoudi, G.M. Martinet, A. Olivier, H. Saugnac
    IPN, Orsay
  Funding: EU, CNRS-IN2P3.

In the frame of the CARE project activities, supported by EU, IPN Orsay participate to the development of a fast cold tuning system for SRF cavities operating at a temperature T=2 K. The study is aimed at full characterization of piezoelectric actuators at low temperature. A new experimental facility was developed for testing various prototypes piezoelectric actuators and successfully operated for T in the range 1.8 K-300 K. Different parameters were investigated as function of T: piezoelectric actuator displacement vs. applied voltage V, capacitance vs. T, dielectric and thermal properties vs. T and finally heating DT due to dielectric losses vs. modulating voltage Vmod and frequency. We observed a decrease of the Full Range Displacement (FRD or DX) of the actuator from ~40μm @ 300K down to 1.8μm-3μm @ 1.8K, depending on both material and fabrication process of the piezostacks. Besides, both material and fabrication process have a strong influence on the shape of the characteristics DX vs. T dependence. Moreover, the variations of losses tangent with T show a maximum at T in the range 30 K-120 K. Finally a dedicated facility located at CERI (Orléans, France) for radiation hardness tests of actuators with fast neutrons at T=4.2 K was developed and the first beam tests results are summarized.

 
 
FOAB002 Advances in X-Band and S-Band Linear Accelerators for Security, NDT, and Other Applications electron, radiation, gun, vacuum 240
 
  • A.V. Mishin
    AS&E, Billerica, Massachusetts
  At AS&E High Energy Systems Division, we designed several new advanced high energy electron beam and X-ray sources. Our primary focus has always been in building the world’s most portable commercial X-band accelerators. Today, our X-band systems frequently exceed performance of the similar S-band machines, while they are more portable compared to the latter. The new designs of the X-band accelerators in the most practical energy range from 1 MeV to 6 MeV have been tested delivering outstanding results. Seventy 6 MeV X-band linacs systems have been produced. The most compact linac for security is used by AS&E in a self-shielded, Shaped Energy™ cargo screening system. We pioneered using the X-band linear accelerators for CT, producing high quality images of oil pipes and wood logs. An X-band linear accelerator head on a robotic arm has been used for electron beam radiation curing of an odd-shaped graphite composite part. We developed the broad-range 4 MeV to over 10 MeV energy-regulated X-band and S-band systems for medical and NDT applications. The regulated pulse length systems operating in a range from nanoseconds to microseconds have been built both in X-band and in S-band frequency range.  
 
FOAB005 Technology for Fissionable Materials Detection by Use of 100 MeV Variable Linac photon, electron, background, simulation 446
 
  • S.P. Karasyov, A.N. Dovbnja, L. Eran, Y.P. Melnik, Y. Ran'iuk, I.N. Shlyakhov
    NSC/KIPT, Kharkov
  • A.J. Baratta
    Penn State University, University Park, Pennsylvania
  • N.M. Kiryukhin
    ATSU, Kiev
  • S.V. Trubnikov
    KhNU, Kharkov
  Funding: This project is funded by CRDF FSTM UKE2-5023-KH-04.

A new concept for a two-step facility to increase the accuracy/reliability of detecting heavily shielded fissionable materials (FM) in marine containers is presented. The facility will detect FM in two steps. An existing dual-view; dual-energy X-ray scanner, which is based on 7 MeV electron accelerator, will select the suspicious places inside container. The linac with variable energy (up to 100 MeV) will be used for the second step. The technology will detect fissionable nuclei by gamma induced fission reactions and delayed neutron registration. A little-known Ukrainian experimental data obtained in Chernobil’ clean-up program will be presented to ground proposed concept. The theoretical calculations of neutron fluxes scale these results to marine container size. Modified GEANT code for electron/gamma penetration and authors’ own software for neutron yield/penetration are used for these calculations. Available facilities (X-ray scanners; linac; detectors), which will be used for concept proof, are described. The results of the first experiments by use variable energy linac are cited.

 
 
FOAB009 The Frankfurt Funneling Experiment rfq, ion, emittance, 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.