Keyword: vacuum
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MOOBB03 An Alternative 1D Model for CSR with Chamber Shielding impedance, shielding, radiation, synchrotron 52
 
  • D. Zhou
    KEK, Ibaraki, Japan
  
  An alternative 1D model for modeling the longitudinal coherent synchrotron radiation (CSR) impedance is proposed. The code CSRZ* is used to calculate the CSR impedance with rectangular chamber shielding. Along the beam orbit, which may be formed by multi bends interleaved with drifts, the vacuum chamber is sliced into a series of segments. The low-frequency CSR impedance for each segment, in this case chamber shielding is significant, is obtained by numerical calculations. The high-frequency CSR impedance, in this case chamber shielding is negligible, is estimated by an analytical model**. The wake kick at each segment is computed via inverse Fourier transform of the impedance convolved the the beam spectrum. The most attractive merit of the method for CSR modeling lies in taking into account the realistic chamber shielding.
* D. Zhou, et al., To be published in Jpn. J. Appl. Phys.
** M. Borland, Phys. Rev. ST Accel. Beams 4, 070701 (2001). 		 
slides icon Slides MOOBB03 [1.856 MB]  
 
MOEPPB013 Simulation and Measurement of Beam Loss in the Narrow-Gap Undulator Straight Section of the Advanced Photon Source Storage Ring undulator, simulation, radiation, neutron 106
 
  • J.C. Dooling, M. Borland
    ANL, Argonne, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357.
Simulations indicate the removal of a scraper/collimator in the Sector 37 straight section (SS) of the Advanced Photon Source storage ring (SR) results in increased beam loss in the remaining narrow-gap, insertion device SS, ID4. Modeling with elegant provides loss distributions in the 5-mm aperture vacuum chamber of ID4 and includes the effects of rf system muting and quantum excitation in the bunch. The loss distributions are then used as input to a MARS model of the SS that includes undulator geometry. ID4 has been instrumented with additional monitoring to capture beam loss events, particularly beam dumps. Cerenkov detectors and fiber-optic cable bundles are used to capture temporal profiles of beam loss events. Beam dumps deliver 2600 J to the vacuum chamber and surrounding hardware including undulators. Data indicate a variety of temporal profiles occur during the beam dumps, with the shortest lasting 6 microseconds, FWHM (<2 turns). Such high power and power densities can lead to physical damage of vacuum components if not handled correctly. Touschek scattering loss is also a concern for undulator demagnetization. Comparison of modeling and measurements will be presented. 		 
 
MOPPC009 Multipactor for E-cloud Diagnostics electron, resonance, cyclotron, dipole 139
 
  • P. Costa Pinto, F. Caspers, P. Edwards, M. Holz, M. Taborelli
    CERN, Geneva, Switzerland
  
  Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed though a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic field. Preliminary result show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the event of a large scale coating production this technique will be a valuable resource for quality control.  
 
MOPPC019 Secondary Electron Yield Measurements of Fermilab’s Main Injector Vacuum Vessel electron, gun, synchrotron, controls 166
 
  • D.J. Scott, D. Capista, K.L. Duel, R.M. Zwaska
    Fermilab, Batavia, USA
  • S. Greenwald, W. Hartung, Y. Li, T.P. Moore, M.A. Palmer
    CLASSE, Ithaca, New York, USA
  • R.E. Kirby, M.T.F. Pivi, L. Wang
    SLAC, Menlo Park, California, USA
  
  We discuss the progress made on a new installation in Fermilab’s Main Injector that will help investigate the electron cloud phenomenon by making direct measurements of the secondary electron yield (SEY) of samples irradiated in the accelerator. In the Project X upgrade the Main Injector will have its beam intensity increased by a factor of three compared to current operations. This may result in the beam being subject to instabilities from the electron cloud. Measured SEY values can be used to further constrain simulations and aid our extrapolation to Project X intensities. The SEY test-stand, developed in conjunction with Cornell and SLAC, is capable of measuring the SEY from samples using an incident electron beam when the samples are biased at different voltages. We present the design and manufacture of the test-stand and the results of initial laboratory tests on samples prior to installation.  
 
MOPPC052 Calculation of Synchrotron Radiation from High Intensity Electron Beam at eRHIC photon, radiation, electron, synchrotron 247
 
  • Y.C. Jing, O.V. Chubar, V. Litvinenko
    BNL, Upton, Long Island, New York, USA
  
  The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab adds an electron beam line to the existing RHIC and improves the luminosity by at least 2 orders of magnitude. It requires a high energy and high intensity electron beam. Thus the synchrotron radiation (SR) coming from the bending magnets and large quadrupoles could be penetrating the vacuum chamber and providing hazard to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity and power density distributions on the chamber wall, suggest the wall thickness required to stop the SR, calculate heat load on the chamber, and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.  
 
MOPPC057 Some Comments to Magnetic Field Representation for Beam Dynamic Calculations multipole, dipole, quadrupole, resonance 262
 
  • P. Schnizer, E.S. Fischer
    GSI, Darmstadt, Germany
  • A. Mierau
    TEMF, TU Darmstadt, Darmstadt, Germany
  • B. Schnizer
    TUG/ITP, Graz, Austria
  
  Machines with high currents and small apertures, as used for SIS100 of the FAIR project, require a sincere understanding of the resonances excited by the magnetic field distortions; typically performed by tracking codes. These codes model the field errors using a Taylor Series approximation of the field quality at the track of the ideal particle. The path of the particle within the elliptic aperture of the dipole is curved; thus the standard approach of using plane circular multipoles fails to model the real symmetry of the magnetic field, an important feature of effective field description for beam loss calculations. Therefore toroidal elliptic multipoles were developed which allow describing the magnetic field concisely in an elliptic vacuum chamber in curved dipoles and quadrupoles. In this talk we present the appropriate description and its limitation, illustrate their usefullness based on the static and transient magnetic field measurements of the first curved SIS100 dipole next to the SIS18 dipole.  
 
MOPPC064 Simulation of the Behavior of Ionized Residual Gas in the Field of Electrodes ion, simulation, electron, emittance 283
 
  • G. Pöplau, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • A. Meseck
    HZB, Berlin, Germany
  
  Funding: Work supported by BMBF under contract number 05K10HRC
Light sources of the next generation such as ERLs require minimal beam losses as well as a stable beam position and emittance over the time. Instabilities caused by ionized residual gas have to be avoided. In this paper we present simulations of the behavior of ionized residual gas in the field of clearing electrodes and investigate e.g. clearing times. For these simulations we apply MOEVE PIC Tracking developed at Rostock University. We demonstrate numerical results with parameters planed for the ERL BERLinPro. 		 
 
MOPPC067 Design and Construction of Inductive BPM simulation, impedance, electron, resonance 289
 
  • M.Sh. Shafiee, E.E. Ebrahimibasabi, S.A.H. Feghhi, N. Goudarzi
    sbu, Tehran, Iran
  • M. Jafarzadeh
    ILSF, Tehran, Iran
  
  To have a controllable Electron machine, that is required to be able to control beam orbits by knowing the beam position. The basic requirement for detecting the position of electron is calibrating and testing the BPMs. For this purpose wire method is used. Since we hadn't access to accelerator, for having experience at beam diagnostic we used this method for testing our constructed inductive BPM including 4 cm square poly ethylene core with 15 turns coil in each side. In this case study that was tested by a pulsed current (as an electron bunch) produced by a pulse generator. At first Tektronix 2235A oscilloscope was calibrated and used to measure the induced voltage of each coils, then by using of microcontroller, protocol RS232 and GUI induced voltages were read. The electrical center was measured with respect to the mechanical center and wire position was detected with 1mm Resolution. Conversion between the BPM signals and the actual wire position were done. Results were compared and presented.  
 
MOPPC096 Multiphysics Applications of ACE3P simulation, HOM, cavity, SRF 361
 
  • K.H. Lee, C. Ko, Z. Li, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California, USA
  • G. Cheng, H. Wang
    JLAB, Newport News, Virginia, USA
  
  Funding: Work supported by US DOE Offices of HEP, ASCR and BES under contract AC02-76SF00515.
The TEM3P module of ACE3P, a parallel finite-element electromagnetic code suite from SLAC, focuses on the multiphysics simulation capabilities, including thermal and mechanical analysis for accelerator applications. In this pa- per, thermal analysis of coupler feedthroughs to supercon- ducting rf (SRF) cavities will be presented. For the realistic simulation, internal boundary condition is implemented to capture RF heating effects on the surface shared by a di- electric and a conductor. The multiphysics simulation with TEM3P matched the measurement within 0.4%. 		 
 
MOPPD007 Towards Routine Operation of the Scintillation Profile Monitor at COSY electron, injection, synchrotron, proton 382
 
  • V. Kamerdzhiev, J. Dietrich, K. Reimers
    FZJ, Jülich, Germany
  • C. Böhme
    ESS, Lund, Sweden
  • A. Pernizki
    INP, Jülich, Germany
  
  The optics of the Scintillation Profile Monitor (SPM) was modified to correct the large error observed in previous measurements. Beam profile measurements were carried out after reinstallation in the COSY ring, showing reasonable agreement with profiles, measured with the ionization profile monitor. Performance of the SPM is analyzed. Application of the method in a proton synchrotron is discussed.  
 
MOPPD030 Present Status of RIKEN Ring Cyclotron ion, heavy-ion, cyclotron, linac 433
 
  • Y. Watanabe, M. Fujimaki, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, T. Kageyama, O. Kamigaito, M. Kase, M. Kidera, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, K. Yamada, S. Yokouchi
    RIKEN Nishina Center, Wako, Japan
  • T. Aihara, S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, Y. Kotaka, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, T.O. Ohki, K. Oyamada, J. Shibata, M. Tamura, N. Tsukiori, A. Uchiyama, K. Yadomi, H. Yamauchi
    SHI Accelerator Service Ltd., Tokyo, Japan
  
  The RIKEN Ring Cyclotron (RRC K540) has been in stable operation over twenty-five years, and supplying many kinds of heavy-ion beams to experiments. Since 2007, it has also been supplying beams to the RIBF four Ring cyclotrons including the Super-conducting Ring Cyclotron (SRC K2500). Now the RRC has three kinds of injectors, one is K70 AVF cyclotron for light ions, the second is the variable-frequency linac for heavy ions, and the third is the RILAC2 for using the high intensity very heavy ions like U and Xe. The many combinations of accelerators are possible, and in any acceleration modes, the RRC should works as a first energy booster. A total operation time of the RRC is more than 5000 hr in every year. The present status of the RRC operation will be reported.  
 
MOPPD053 Reduction of Outgassing from the Ferrite Cores in the Kicker Magnet of J-PARC RCS kicker, high-voltage, beam-transport, proton 487
 
  • N. Ogiwara, Y. Hikichi, J. Kamiya, M. Kinsho, M. Nishikawa, K. Suganuma, T. Yanagibashi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  Kicker magnets are used to kick out the accelerated beam to the beam transport lines in the RCS of the J-PARC. A high voltage is applied to kickers for a short period, so they must be installed in a vacuum to prevent discharge. Therefore, it is important to reduce the outgassing of water vapor from the ferrite cores. After bake-out at 200°C for 300 hours, the outgassing rate decreased to less than 1×10-7 Pam/s. However, the small amount of water vapor and carbon monoxide were emitted from the ferrite cores at charging voltage of 80 kV. This time, we have decided to construct the reserve magnets with very low outgassing at high-voltage discharge. First of all, the thermal desorption behavior of the ferrite was investigated. Water vapor has two peaks: at ~ 100°C and 350°C. Carbon monoxide is rather largely emitted until 300°C. From these results, the ferrite cores were vacuum-fired at 450°C for 10 h. Then the good properties for the magnetic cores were confirmed. And now the assembling of the kicker magnet is undertaken. The performance of the kicker magnet made of the vacuum-fired ferrite will be shown in this meeting.  
 
MOPPD059 Proposal of a Dummy Septum to Mitigate Ring Irradiation for the CERN PS Multi-Turn Extraction septum, extraction, beam-losses, shielding 499
 
  • M. Giovannozzi, H. Bartosik, D. Bodart, J. Borburgh, R.J. Brown, S. Damjanovic, S.S. Gilardoni, B. Goddard, C. Hernalsteens, M. Hourican, M. Widorski
    CERN, Geneva, Switzerland
  
  High activation of the magnetic extraction septum of the CERN PS machine was observed due to the losses of the continuous beam extracted via the Multi-Turn Extraction (MTE) method. The resulting activation is however incompatible with safe operation so a mitigation measure was required and found, namely the installation of a passive dummy septum to protect the actual one seems to provide the required reduction in activation in the extraction area. The shielded dummy septum is intended to absorb particles during the rise time of the MTE extraction kickers, avoiding the beam impact on the blade of the active magnetic extraction septum. The principle of the proposed modifications of the PS layout will be presented together with the studies aimed at finalising the new configuration.  
 
MOPPD081 Upgrade of the LHC Beam Dumping Protection Elements simulation, extraction, kicker, dumping 556
 
  • W.J.M. Weterings, T. Antonakakis, B. Balhan, J. Borburgh, B. Goddard, C. Maglioni, R. Versaci
    CERN, Geneva, Switzerland
  
  The Beam Dumping System for the Large Hadron Collider comprises for each ring a set of horizontally deflecting extraction kicker magnets, vertically deflecting steel septa, dilution kickers and finally, a couple of hundred meters further downstream, an absorber block. A mobile diluter (TCDQ) protects the superconducting quadrupole immediately downstream of the extraction as well as the arc at injection energy and the triplet aperture at top energy from bunches with small impact parameters, in case of a beam dump that is not synchronized with the particle free gap or a spontaneous firing of the extraction kickers. Simulations have shown that an asynchronous dump of a 7 TeV nominal beam into the TCDQ absorber blocks could damage it. This paper describes the proposed changes to this device in order to maintain the protection for the downstream elements while reducing the risk of damaging the TCDQ in case of such a beam loss.  
 
MOPPD082 Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array collimation, proton, collider, scattering 559
 
  • D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda
    Fermilab, Batavia, USA
  • Y.A. Chesnokov, I.A. Yazynin
    IHEP, Moscow Region, Russia
  • V. Guidi, A. Mazzolari
    INFN-Ferrara, Ferrara, Italy
  • Yu.M. Ivanov
    PNPI, Gatchina, Leningrad District, Russia
  • D. Mirarchi, S. Redaelli
    CERN, Geneva, Switzerland
  
  Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP).
With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%. 		 
 
MOPPP007 High-intensity Monochromatic Cherenkov Radiation in THz Range by Femtosecond Electron Bunches in Impurity-doped Semiconductor Tube electron, radiation, plasma, wakefield 580
 
  • A. Ogata, K. Kan, T. Kondoh, K. Norizawa, J. Yang, Y. Yoshida
    ISIR, Osaka, Japan
  
  A novel method to generate high-power THz radiation is proposed and the preliminary experiments are conducted. If a beam with a bunch length on the order of 100 fs is injected into an electron–hole plasma of a semiconductor with a plasma frequency on the order of THz, THz wake fields are coherently generated. If the beam moves on the axis of a hollow tube covered by a metal, the frequency spectrum of the radiation is composed of discrete components. Monochromatic radiation is obtained by making only the lowest frequency component coherent. In the preliminary experiments using mm-sized dielectric tubes, the radiation spectra, which was driven by electron bunches of 200fs/27 MeV, were measured directly by a Michelson interferometer and bolometer. Peaks at frequencies of 0.09 and 0.14 THz of transverse magnetic (TM) modes, which corresponded to TM03 and TM04, were observed. The other higher modes, e. g. 0.36 (TM09) and 0.40 THz (TM010), were also observed successfully at a bunch charge of 15 pC, which decreased the electron bunch length.  
 
MOPPP026 Cryogenic Distribution System for the Proposed Cornell ERL Main Linac cryomodule, linac, HOM, cavity 619
 
  • E.N. Smith
    Cornell University, Ithaca, New York, USA
  • Y. He, G.H. Hoffstaetter, M. Liepe, M. Tigner
    CLASSE, Ithaca, New York, USA
  
  Funding: This material is based upon work supported by the National Science Foundation under Grant No. DMR-0807731.
The proposed Cornell ERL main linac requires a total cooling power of nearly 8kW at 1.8K, 5kW at 5K and over 100kW at 80K. This is distributed over approximately 65 cryomodules, each containing 6 rf cavities and associated input couplers and higher order mode absorbers. situated in two underground tunnels. While the total heat load is comparable to that for each of the 8 individual LHC cryoplants, the very high ratio of dynamic heat load to static heat load, combined with the high power density at various sites produces interesting challenges for the cryogenic distribution system. A schematic view of the design choices selected, some of which are different from existing large cryogenic systems, and the basis for these decisions, is presented in this paper. 		 
 
MOPPP039 Masked Photocathode for Photoinjectors electron, cathode, emittance, laser 649
 
  • J. Qiang
    LBNL, Berkeley, California, USA
  
  Funding: This research was supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research used resources of the NERSC.
In this paper, we propose using masked photocathode in photoinjector for generating high brightness electron beam. An electrode with small hole is used as a mask to shield a large size photocathode from accelerating vacuum chamber. Using a mask will significantly increase lifetime of a photocathode by rotating unexplored photocathode material behind the electrode into the hole. Furthermore, the mask helps reduce dark current or secondary electron emission from the photocathode material. It also provides a control of initial beam transverse emittances. 		 
 
MOPPP049 Deposition and In-Situ Characterization of Alkali Antimonide Photocathodes cathode, synchrotron, scattering, diagnostics 670
 
  • X. Liang
    SBU, Stony Brook, New York, USA
  • K. Attenkofer
    ANL, Argonne, USA
  • I. Ben-Zvi, M. Ruiz-Osés
    Stony Brook University, Stony Brook, USA
  • H.A. Padmore, T. Vecchione
    LBNL, Berkeley, California, USA
  • S.G. Schubert
    HZB, Berlin, Germany
  • J. Smedley
    BNL, Upton, Long Island, New York, USA
  
  Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences of the U. S. Department of Energy, under Contract No. KC0407-ALSJNT-I0013, and DE-SC0005713.
Alkali antimonide cathodes have the potential to provide high quantum efficiency for visible light, and are significantly more tolerant of vacuum contaminants than GaAs, so they are attractive for high-average-current photoinjectors to generate high quality electron beams. These cathodes are crystalline; however, standard growth recipes used today do not produce large crystals. We have grown multi-alkali cathodes on silicon and molybdenum substrates with in-situ X-ray diffraction (XRD) and X-ray reflection (XRR) analysis. The correlation of the cathode structure to the growth parameters and quantum efficiency was explored. During the deposition and evaporation of Sb and K layers, the possibility of selective growth of specific crystalline orientation was observed via X-ray diffraction. 		 
 
MOPPP061 Using RADIA to Model Superconducting Wigglers at the Canadian Light Source sextupole, wiggler, insertion, insertion-device 699
 
  • C.K. Baribeau, L.O. Dallin, M.J. Sigrist, W.A. Wurtz
    CLS, Saskatoon, Saskatchewan, Canada
  
  The Canadian Light Source operates two superconducting wigglers: a 2 Tesla, 63 pole wiggler, and a 4 Tesla, 27 pole wiggler. Both SCWs have a negative impact on the injection efficiency. Beam based measurements indicate a larger than expected sextupole moment, and the 4T wiggler produces a large horizontal tune shift. To better understand these effects, computer models were developed for the SCWs using the magnetic modelling software package, RADIA. The RADIA models accurately predict the wiggler on-axis field strength and vertical tune shift. By introducing physical misalignments, the models can produce sextupole moments of the same order of magnitude as the measured quantities. However, the modelled horizontal tune shift is orders of magnitude smaller than the 4T wiggler’s observed tune shift. Various model parameters were investigated for their effect on horizontal tune shift, but the cause of the 4T wiggler’s large horizontal tune shift remains unknown.  
 
MOPPP066 Calculated Spectra from Magnetic Field Measurements of 1.5 m Superconducting Undulator Coils undulator, emittance, permanent-magnet, storage-ring 711
 
  • S. Casalbuoni, T. Baumbach, S. Gerstl, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  • C. Boffo, W. Walter
    BNG, Würzburg, Germany
  
  In this contribution we report on the spectra calculated from the field measurements performed in a liquid helium bath of 1.5 m superconducting undulator coils. The coils are foreseen for a superconducting undulator demonstrator with a period length of 15 mm planned to be installed in ANKA middle 2012 and tested at the new beamline NANO for high resolution X-ray diffraction. The spectral performance at ANKA and at low emittance sources is compared with the competing cryogenic permanent magnet technology.  
 
MOPPP067 In-vacuum, Cryogen-free Field Measurement System for Superconducting Undulator Coils undulator, synchrotron, insertion, insertion-device 714
 
  • A.W. Grau, T. Baumbach, S. Casalbuoni, S. Gerstl, M. Hagelstein, T. Holubek, D. Saez de Jauregui
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  
  The performance of superconducting insertion devices (IDs) depends strongly on the magnetic field quality. Before installing IDs in synchrotron light sources the characterization and precise measurements of their magnetic properties are of fundamental importance. Improvements in magnetic field measurement technology of conventional, i.e. permanent magnet based IDs, made significant progress during the last years and push the capabilities of synchrotron light sources. For superconducting IDs similar major developments are necessary. As a part of our R&D program for superconducting insertion devices we perform quality assessment of their magnetic field properties. This contribution describes details and challenges of the cryostat and measurement setup assembly to perform magnetic measurements of the local field and of the field integrals of superconducting undulator coils in a cold in-vacuum (cryogen free) environment. The focus will be on the outcome of the final acceptance test together with results of first tests performed with mock-up coils.  
 
MOPPP068 Beam Heat Load and Pressure in the Superconducting Undulator Installed at ANKA electron, undulator, storage-ring, simulation 717
 
  • S. Casalbuoni, S. Gerstl, A.W. Grau, T. Holubek, D. Saez de Jauregui
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  
  A superconducting undulator has been installed in the ANKA (ANgstrom source KArlsruhe) storage ring since March 2005. The beam heat load and pressure on the cold bore were analyzed in the first two years of operation, during which the undulator was operated mainly with open gap. We report here on a larger statistic of beam heat load and pressure data collected in the last years with the undulator operated at different gap positions. The effects of vacuum leaks in the storage ring on the superconducting undulator operation are also described.  
 
MOPPP069 First Measurements of COLDDIAG: A Cold Vacuum Chamber for Diagnostics solenoid, electron, diagnostics, insertion 720
 
  • S. Gerstl, T. Baumbach, S. Casalbuoni, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  • R. Bartolini, M.P. Cox, J.C. Schouten, R.P. Walker
    Diamond, Oxfordshire, United Kingdom
  • M. Migliorati, B. Spataro
    INFN/LNF, Frascati (Roma), Italy
  • I.R.R. Shinton
    UMAN, Manchester, United Kingdom
  
  Superconductive insertion devices can reach, for the same gap and period length, higher fields with respect to permanent magnet insertion devices. One of the still open issues for the development of superconductive insertion devices, is the understanding of the heat intake from the electron beam. COLDDIAG, a cold vacuum chamber for diagnostics was designed and built specifically for this purpose. With the equipped instrumentation, which covers temperature sensors, pressure gauges, mass spectrometers as well as retarding field analyzers it is possible to measure the beam heat load, total pressure, gas content as well as the flux of particles hitting the chamber walls. Here we report about the preliminary measurements and results of COLDDIAG installed in the Diamond storage ring.  
 
MOPPP070 Characterization of Vacuum Chamber Samples for Superconducting Insertion Devices undulator, storage-ring, insertion, insertion-device 723
 
  • D. Saez de Jauregui, T. Baumbach, S. Casalbuoni, S. Gerstl, A.W. Grau, M. Hagelstein, C. Heske, T. Holubek, B. Krause, A. Seiler, S. Stankov, L. Weinhardt
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  • C.Z. Antoine, Y. Boudigou
    CEA/IRFU, Gif-sur-Yvette, France
  • C. Boffo
    BNG, Würzburg, Germany
  
  One of the key components of a superconducting insertion device is the ultra-high vacuum (UHV) chamber. In order to reach the accelerator UHV specifications, it is very important to control the surface chemical content and find proper cleaning procedures. To keep the geometric and resistive wall losses small, it is essential that the top few μm of the surface exhibits low roughness and good electrical conductivity at low temperatures. A 300-μm-thick 316L stainless steel foil, galvanized with a 30-μm copper layer, is used for the next superconducting undulator developed in a collaboration between KIT and BNG. We report here on different spectroscopic analyses as well as on residual resistivity ratio RRR measurements of the copper surface after cleaning procedures and annealing at various temperatures for different periods of time.  
 
MOPPP071 In Vacuum Conduction Cooled Superconducting Switch for Insertion Devices with Variable Period Length power-supply, insertion, insertion-device, FEL 726
 
  • T. Holubek, T. Baumbach, S. Casalbuoni, S. Gerstl, A.W. Grau, M. Hagelstein, D. Saez de Jauregui
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  • C. Boffo, W. Walter
    BNG, Würzburg, Germany
  
  Switching the period length allows to increase the tunability of an insertion device. This can be realized in superconducting insertion devices (IDs) by reversing the current in a separately powered subsets of the superconducting windings. In order to use only one power supply instead of two for the two circuits, reducing the thermal input to the device, work is ongoing at ANKA to develop a superconducting switch. In this work we present the results of the test of an in-vacuum housed, conduction-cooled superconducting switch.  
 
MOPPP077 Heat Load Budget on TPS Undulator in Vacuum undulator, synchrotron, radiation, synchrotron-radiation 741
 
  • J.C. Huang, J. Chen, C.-S. Hwang, F.-Y. Lin, Y.T. Yu
    NSRRC, Hsinchu, Taiwan
  
  The performance of an insertion device is limited by the magnet gap because a small gap affects the dynamic aperture and results in a short life time of the beam. An in-vacuum undulator is designed to have no vacuum chamber between the magnet arrays so to allow the entire magnet gap to be fully used for the dynamic aperture. An in-vacuum undulator can optimally minimize the gap to achieve continuous energy spectra. One problem of an undulator with a small gap is resistive wall heating by the image current. The heat load depends strongly on the injected mode in the storage ring; injection of multiple bunches might deteriorate the thermal performance for the magnet array. In this paper, we present a calculation of the heat load budget for a magnet array of an in-vacuum undulator of Taiwan Photon Source (TPS).  
 
MOPPP080 New Concepts for Revolver Undulator Designs undulator, insertion, insertion-device, controls 750
 
  • B.K. Stillwell, J.H. Grimmer, D.P. Pasholk, E. Trakhtenberg
    ANL, Argonne, USA
  • M.B. Patil
    Impact Engineering Solutions, Brookfield, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Dynamic support of revolver undulator magnet structures presents a challenging mechanical problem. Some designs to date employ a support span connected at its ends to the undulator gap separation mechanism. However, this arrangement is problematic for long undulators operating at small gaps since the gap-dependent distortion of the magnet support span scales approximately with the cube of its length and exponentially with reduction in gap. Other designs have been demonstrated that utilize intermediate connections to a central magnet support span, but require additional stiffening members between that span and the magnet arrays. This arrangement is difficult to implement at the APS because of space constraints imposed by existing beam vacuum chambers. We have developed three revolver undulator concepts that provide an extremely rigid magnet support structure, precise rotational positioning, and wide gap tapering ability. Each of the concepts has advantages and disadvantages. All of the concepts are fully compatible with the existing APS-designed gap separation mechanism, which will greatly simplify testing and implementation. 		 
 
MOPPP089 Development of a PrFeB Cryogenic Undulator at NSLS-II undulator, cryogenics, synchrotron, permanent-magnet 762
 
  • C.A. Kitegi, P. Cappadoro, O.V. Chubar, T.M. Corwin, H.C. Fernandes, D.A. Harder, P. He, G. Rakowsky, J. Rank, C. Rhein, T. Tanabe
    BNL, Upton, Long Island, New York, USA
  
  Recent cryogenic undulators use Praseodymium-Iron-Boron (PrFeB) magnets cooled down to 80K. The main drawn drawback of the PrFeB magnet grades developed so far are their relative low coercive field at ambient temperature, below 2 T which prevents PrFeB based cryogenic undulator from baking. Some precautions are required during the undulator assembling and shimming to ensure ultra high vacuum compatibility. However Hitachi Metal Industry (HMI) recently developed two different grades of PrFeB magnet with large coercive field but at the expense of the remanent field. The magnetization curves have been measured from 40 K up to 400 K to determine the field increase and to investigate the magnet withstanding to baking. An IVU prototype has also been baked. Magnetic measurements before and after baking are also presented.  
 
MOPPP090 Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings undulator, electron, photon, radiation 765
 
  • O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe
    BNL, Upton, Long Island, New York, USA
  • J.A. Clarke
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: US DOE, Contract No. DE-AC02-98CH10886.
We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations. 		 
 
MOPPR012 Beam Induced Fluorescence Monitors for FAIR electron, ion, target, antiproton 798
 
  • F. Becker, C.A. Andre, C. Dorn, P. Forck, R. Haseitl, B. Walasek-Höhne
    GSI, Darmstadt, Germany
  • T. Dandl, T. Heindl, A. Ulrich
    TUM/Physik, Garching bei München, Germany
  
  Online profile diagnostic is preferred to monitor intense hadron beams at the Facility of Antiproton and Ion Research (FAIR). One instrument for beam profile measurement is the gas based Beam Induced Fluorescence (BIF)-monitor. It relies on the optical fluorescence of residual gas, excited by beam particles. Depending on the beam parameters and vacuum constraints, BIF monitors can be operated at base pressure or in dedicated local pressure bumps. Spectroscopic data in nitrogen and rare gases confirms an exploitable dynamic range from UHV to atmospheric pressure. Optical transitions and corresponding beam profiles are discussed for gas pressures from 10-3 to 30 mbar. Fundamental limitations for some application scenarios will be addressed as well.  
 
MOPPR023 Stripline BPM with Integral In-Vacuo Termination impedance, pick-up, quadrupole, coupling 828
 
  • A. Stella, A. Ghigo, V.L. Lollo, F. Marcellini, M. Serio
    INFN/LNF, Frascati (Roma), Italy
  
  We report the design and realization of a stripline type beam position monitor to be used in the SPARC LAB transfer lines. While the directional properties provided by matched termination at the downstream end are not strictly required in a transfer line, yet matched loads at the end of the stripline electrodes are preferable to reduce the loss factor and to avoid unwanted reflection to the detection electronic. The Integration of a matched resistive load inside the vacuum chamber allows to halve the number of UHV feedthroughs.  
 
MOPPR029 Upgrade of Ionization Profile Monitor (IPM) in the J-PARC 3-GeV RCS electron, ion, status, space-charge 840
 
  • H. Harada, K. Yamamoto, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  Ionization Profile Monitors (IPM) were installed and operated in the J-PARC 3-GeV RCS for the observation of circulating beam profile. In IPM system, ions produced by the beam passing through beam chamber lead to Multi Channel Plate (MCP) by electric field, and the signals from the MCP are observed as the beam profile. The IPM system has an upgrade plan for the optimization of the electric fields. This will be reported the upgrade status of the IPM.  
 
MOPPR040 Design and Measurements of a Test Stand for the SEM-Grid System of the ESS-BILBAO electron, diagnostics, emittance, linac 867
 
  • D. Belver, J. Feuchtwanger, P.J. González
    ESS Bilbao, LEIOA, Spain
  • F.J. Bermejo
    Bilbao, Faculty of Science and Technology, Bilbao, Spain
  • V. Etxebarria, J. Jugo
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  
  In the framework of the ESS-Bilbao accelerator, a test stand for the development of Secondary Electron EMission grid (SEM-Grid) has been designed and manufactured as a part of the diagnostics system for beam profile measurements. This test stand is a vacuum system based on an EQ 22/35 electron source from SPECS used as a beam injector. This electron source has an energy range from 0 to 5 KeV and a maximum beam current up to 200 μA. Although we have thought in a SEM-Grid of 40 wires (20 wires in each X and Y direction), two prototypes of 16 wires (8x8) of 250 μm diameter and spaced 1 and 2 mm, respectively, have been developed due to its easier implementation and tested in the test stand. In order to develop an electronics readout system for the SEM-Grid, first studies of the prototype signals have been done. The secondary emission current of each wire will be integrated and amplified to provide a significant voltage signal that can be measured by our acquisition system. A description of the SEM-Grid test stand and the measurements developed is given here.  
 
MOPPR043 Design, Construction and Calibration of a First Prototype of Beam Position System for Hadron Therapy Facilities controls, proton, power-supply, high-voltage 876
 
  • A. Faus-Golfe, C. Belver-Aguilar, C. Blanch Gutierrez, J.J. García-Garrigós
    IFIC, Valencia, Spain
  • E. Benveniste, M. Haguenauer, P. Poilleux
    LLR, Palaiseau, France
  
  Funding: AIC10-D-000518 and AIC-D-2011-0673.
Beam Position Monitors (BPM) are essential elements in the instrumentation for the beam control in hadron therapy accelerators. The measurement of the beam position become more important at the secondary transport lines towards the patient room where this parameter must be completely determined. In this paper we describe the design, construction, read-out electronics and first calibration tests of a new type of BPM based on four scintillating fibers coupled to four photodiodes to detect the light produced by the fibers when intercepting the beam tails. The prototype will serve to evaluate the different design options in the mechanical and the read-out electronics implementation as well as to define the best processing method to get the beam position. 		 
 
MOPPR055 A Two-dimensional Wire Scanner for a Low Energy Ion Beam ion, diagnostics, ion-source, acceleration 909
 
  • C. Gabor
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • G.E. Boorman
    Royal Holloway, University of London, Surrey, United Kingdom
  • A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) is intended to demonstrate the early stages of acceleration for future high power proton applications. So far, the H− ion source and the low energy beam transport (LEBT) are operational. The commissioning of the LEBT is carried out with a multipurpose diagnostics vessel. On the other hand, the present status of the LEBT does not provide any permanent installed beam diagnostics beyond current measurement. Possible diagnostics need to be compact and rigid in a way that it can survive an area with potentially high beam losses and not suffering to much of beam noise. Furthermore, minimal invasive diagnostics is preferred. It is intended to present first results of a wire scanner where the geometry has been changed in a way that the two dimensional xy-space is accessible.  
 
MOPPR063 Exploiting the Undesired: Beam-gas Interactions in the LHC radiation, simulation, proton, quadrupole 927
 
  • R. Versaci, V. Baglin, M. Brugger
    CERN, Geneva, Switzerland
  • A. Mereghetti
    UMAN, Manchester, United Kingdom
  
  The vacuum inside the LHC pipes has a key role in correct operation of the accelerator. The interaction of the beam with residual gas in the pipes can lead to the loss of the beam itself and damage accelerator components. Nevertheless, beam-gas interactions can be exploited to indirectly measure the gas pressure inside the beam pipe, detecting the secondaries produced. The showers generated are detected by Beam Loss Monitors, whose signals depend on the gas pressure. This technique would also allow to punctually measure the gas pressure in sections of the accelerator where vacuum gauges are not frequent, such as the arcs. The problem has been addressed by means of FLUKA simulations and the results have been benchmarked with direct measurements performed in the LHC in 2011.  
 
MOPPR074 Using TE Wave Resonances for the Measurement of Electron Cloud Density resonance, cavity, electron, simulation 960
 
  • J.P. Sikora, M.G. Billing, D. L. Rubin, R.M. Schwartz
    CLASSE, Ithaca, New York, USA
  • D. Alesini
    INFN/LNF, Frascati (Roma), Italy
  • B.T. Carlson
    CMU, Pittsburgh, Pennsylvania, USA
  • S. De Santis
    LBNL, Berkeley, California, USA
  • K.C. Hammond
    Harvard University, Cambridge, Massachusetts, USA
  
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy under Contracts DE-FC02-08ER41538, DE-AC02-05CH11231.
In the past few years, electron cloud density has been measured by means of its effect on TE waves propagated through the accelerator vacuum chamber. This technique has been the object of careful studies and has been used in several laboratories around the world (CERN, SLAC, FNAL, Cornell, INFN-LNF). Recent measurements at CesrTA and DAΦNE show that in a majority of practical cases, the theoretical model that relates the cloud density to the phase shift induced on a TE wave propagating in beam pipe may not be the correct one. Instead, the measurement results have to be analyzed considering the effect of the electron cloud on a standing wave excited between the input and output couplers - typically Beam Position Monitors (BPMs). This standing wave pattern is not confined to the portion of beampipe between the BPMs and must be understood in order to correctly interpret the measurement. In this paper we present evidence that the transmission function near cutoff between two BPMs is the result of coupling to standing waves trapped in the vacuum chamber. This evidence includes measurements at DAΦNE, Cesr-TA, a test waveguide, computer EM simulations, and analytical calculations. 		 
 
MOPPR083 Mechanical Design and Evaluation of the MP-11-like Wire Scanner Prototype laser, controls, linac, neutron 984
 
  • S. Rodriguez Esparza, J.D. Gilpatrick, M.E. Gruchalla, A.J. Maestas, J.P. Martinez, J.L. Raybun, F.D. Sattler, J.D. Sedillo, B.G. Smith
    LANL, Los Alamos, New Mexico, USA
  
  A wire scanner (WS) is a linearly actuated diagnostic device that uses fiber wires (such as Tungsten or Silicon Carbide) to obtain the position and intensity profile of the proton beam at the Los Alamos Neutron Science Center (LANSCE) particle accelerator. LANSCE will be installing approximately 86 new WS in the near future as part of the LANSCE Risk Mitigation project. These 86 new WS include the replacement of many current WS and some newly added to the current linear accelerator and other beam lines. The reason for the replacement and addition of WS is that many of the existing actuators have parts that are no longer readily available and are difficult to find, thus making maintenance very difficult. One of the main goals is to construct the new WS with as many commercially-available-off-the-shelf components as possible. In addition, faster beam scans (both mechanically and in term of data acquisition) are desired for better operation of the accelerator. This document outlines the mechanical design of the new MP-11-like WS prototype and compares it to a previously built and tested SNS-like WS prototype.  
 
TUXA02 Upgrade Plans for the LHC Injector Complex linac, injection, electron, feedback 1010
 
  • R. Garoby, H. Damerau, S.S. Gilardoni, B. Goddard, K. Hanke, A.M. Lombardi, M. Meddahi, B. Mikulec, E.N. Shaposhnikova, M. Vretenar
    CERN, Geneva, Switzerland
  
  Challenging beams with much higher brightness than today are required for the LHC to achieve its high luminosity objective after the year 2020. It is the purpose of the LHC Injectors Upgrade (LIU) Project to achieve this result, consolidating and upgrading the existing set of ageing synchrotrons (PSB, PS and SPS), and using the new linac presently in construction (Linac4). The anticipated beam characteristics are described and compared to the known limitations in the different accelerators. The foreseen solutions are outlined as well as the planning for their implementation.  
slides icon Slides TUXA02 [72.367 MB]  
 
TUYB02 Manufacture and Testing of Optical-scale Accelerator Structures from Silicon and Silica laser, electron, coupling, acceleration 1050
 
  • R.J. England, E.R. Colby, R. Laouar, C. McGuinness, B. Montazeri, R.J. Noble, K. Soong, J.E. Spencer, D.R. Walz, Z. Wu
    SLAC, Menlo Park, California, USA
  • R.L. Byer, C.M. Chang, K.J. Leedle, E.A. Peralta
    Stanford University, Stanford, California, USA
  • B.M. Cowan
    Tech-X, Boulder, Colorado, USA
  • M. Qi
    Purdue University, West Lafayette, Indiana, USA
  
  We report on recent progress in the design, manufacture and testing of optical-scale accelerator structures made from silicon and silica. The potential of these structures for the development of extremely compact, efficient, and low cost accelerators producing attosecond electron pulses will be discussed, together with various possible applications.  
slides icon Slides TUYB02 [17.226 MB]  
 
TUOBC03 Experimental Measurements of e-Cloud Mitigation using Clearing Electrodes in the DAΦNE Collider positron, wiggler, dipole, electron 1107
 
  • D. Alesini, T. Demma, A. Drago, A. Gallo, S. Guiducci, C. Milardi, P. Raimondi, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • S. De Santis
    LBNL, Berkeley, California, USA
  
  Recently the electron-positron collider DAΦNE has started delivering luminosity to the KLOE-2 experiment. For this run special metallic electrodes for e-cloud clearing were installed in all the dipole and wiggler magnets of the collider positron ring. Experimental measurements of the effectiveness of the electrodes in the mitigation of the e-cloud effects in the positron beam have been done showing an impressive effectiveness of these devices in the cure of the e-cloud effects in the positron beam. In particular the electrodes allow reducing the vertical beam size increase, the growth rate of transverse instabilities and the tune shifts induced by the electron cloud. Frequency shifts measurements of the vacuum chamber resonances switching on and off the electrodes have also been done showing their effect in the reduction of the electron cloud density. In this paper we summarize the results of all our observations and the experimental measurements of the e-cloud suppression with these electrodes.  
slides icon Slides TUOBC03 [2.825 MB]  
 
TUPPC022 Straight Scaling FFAG Experiment emittance, linac, closed-orbit, instrumentation 1209
 
  • J.-B. Lagrange, Y. Ishi, Y. Kuriyama, Y. Mori, R. Nakano, B. Qin, T. Uesugi, E. Yamakawa
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • Y. Niwa, K. Okabe, I. Sakai
    University of Fukui, Faculty of Engineering, Fukui, Japan
  
  Straight scaling FFAG experiment has been done at Kyoto University research reactor institute. Details and results are presented here.  
 
TUPPC086 Conceptual Design of the CLIC damping rings emittance, wiggler, damping, positron 1368
 
  • Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann
    CERN, Geneva, Switzerland
  • C. Belver-Aguilar, A. Faus-Golfe
    IFIC, Valencia, Spain
  • A. Bernhard
    KIT, Karlsruhe, Germany
  • M.J. Boland
    ASCo, Clayton, Victoria, Australia
  • A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev
    BINP SB RAS, Novosibirsk, Russia
  • M. Korostelev
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • E. Koukovini
    EPFL, Lausanne, Switzerland
  • M.A. Palmer
    CLASSE, Ithaca, New York, USA
  • M.T.F. Pivi, S.R. Smith
    SLAC, Menlo Park, California, USA
  • R.P. Rassool, K.P. Wootton
    The University of Melbourne, Melbourne, Australia
  • L. Rinolfi
    JUAS, Archamps, France
  • A. Vivoli
    Fermilab, Batavia, USA
  
  The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.  
 
TUPPD015 Optimization of Muon Capturing in g-2 Ring kicker, betatron, impedance, closed-orbit 1440
 
  • A.A. Mikhailichenko
    CLASSE, Ithaca, New York, USA
  • D.L. Rubin
    Cornell University, Ithaca, New York, USA
  
  We describe optimization procedure for muons capturing in g-2 ring under reconstruction at FERMILAB. This procedure includes both the beam dynamics consideration and HV inflector geometry and technique. Some engineering aspects of HV inflector and pulser are presented in detail.  
 
TUPPD017 Electromagnetic Design of RF Cavities for Accelerating Low-Energy Muons cavity, linac, resonance, solenoid 1446
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
  
  A high-gradient linear accelerator for accelerating low-energy muons and pions in a strong solenoidal magnetic field has been proposed for homeland defense and industrial applications.* The acceleration starts immediately after collection of pions from a target in a solenoidal magnetic field and brings decay muons, which initially have kinetic energies mostly around 15-20 MeV, to 200 MeV over a distance of ~10 m. At this energy, both ionization cooling and further, more conventional acceleration of the muon beam become feasible. A normal-conducting linac with external-solenoid focusing can provide the required large beam acceptances. The linac consists of independently fed zero-mode (TM010) RF cavities with wide beam apertures closed by thin conducting edge-cooled windows. Electromagnetic design of the cavity, including its RF coupler, tuning and vacuum elements, and field probes, has been developed with the CST MicroWave Studio, and will be presented.
* S.S. Kurennoy, A.J. Jason, H. Miyadera, “Large-Acceptance Linac for Accelerating Low-Energy Muons.” Proceed. IPAC10, p. 3518.
 		 
 
TUPPD042 Design of Transmission Line at 28 GHz, 10 kW for ECR Ion Source in KBSI ion, ion-source, ECRIS, plasma 1494
 
  • M. Won, S. Choi, B.C. Kim, B.S. Lee, J.W. Ok, J.Y. Park, J.H. Yoon
    Korea Basic Science Institute, Busan, Republic of Korea
  
  The 28 GHz gyrotron system was designed to deliver the microwave power from gyrotron oscillator to an electron cyclotron resonance ion source (ECRIS) for simultaneously producing high current and highly charged ions. The microwave power from 28 GHz gyrotron were measured from the range between 0.5 kW and 10 kW with frequency variation from 27.9740 to 27.9893 GHz. The gyrotron oscillator of transmission system operates in continuous wave regime with the smoothly regulated output microwave power. A transmission line was designed for the transport of microwaves to an ion source. For the electrical insulation between gyrotron system and ion source chamber applied to high voltage, we installed a DC break. In order to evaluate gyrotron operation, a dummy load was developed to consume such high microwave power.  
 
TUPPD045 Efficient Plasma Generation by Positive Circulating Beams electron, ion, proton, plasma 1503
 
  • V.G. Dudnikov, C.M. Ankenbrandt
    Muons, Inc, Batavia, USA
  
  Performances of high brightness circulating beams are affected by development of strong “electron-proton” (e-p) instabilities connected with generation of an electron cloud (EC). For suppression of the EC generation it is proposed a coating of vacuum chambers by compounds with low secondary electron emission, which is very complex and expensive for large systems like LHC or RHIC. Threshold beam intensity for EC generation can be increased during the vacuum chamber bombarding by plasma particles generating by EC. Vacuum chamber processing (scrubbing) by EC is conducted by bunched beam with a highest possible intensity and with shortest gaps between bunches. Highly efficient plasma generation can be produced in the coasting circulating beam of positive particles with relative low intensity and energy. With the coasting positive beam the plasma particles are generating by low energy electrons trapped by a positive beam space charge. Dynamics of electrons and ions generation will be estimated and simulated. The rate of plasma generation and surface scrubbing can be increase by decrease of pumping and injection of selected gases.  
 
TUPPD052 A New Load Lock System for the Source of Polarized Electrons at ELSA electron, polarization, laser, ion 1521
 
  • D. Heiliger, W. Hillert, B. Neff
    ELSA, Bonn, Germany
  
  Funding: supported by DFG (SFB/TR16)
Since 2000, an inverted source of polarized electrons at the electron stretcher accelerator ELSA routinely provides a pulsed beam with a current of 100 mA and a polarization degree of about 80%. One micro-second long pulses with 100 nC charge are produced by irradiating a GaAs strained-layer superlattice photocathode (8 mm in diameter) with laser light. Future accelerator operation requires a significantly higher beam intensity, which can be achieved by using photocathodes with sufficiently high quantum efficiency. Therefore, and in order to enhance the reliability and up time of the source, a new extreme high-vacuum (XHV) load lock system was installed and commissioned at the beginning of this year. It consists of three chambers: The activation chamber for heat cleaning of the photocathodes and activation with cesium and oxygen. The storage chamber in which up to five different types of photocathodes with various diameters of the emitting surface can be stored under XHV conditions. The loading chamber in which an atomic hydrogen source is used to remove any remaining surface oxidation. Additionally, tests of the photocathodes’ properties can be performed during operation. 		 
 
TUPPD054 Research Activities on Photocathodes for HZDR SRF Gun gun, cathode, SRF, electron 1524
 
  • R. Xiang
    FZD, Dresden, Germany
  • A. Arnold, M. Freitag, P. Michel, P. Murcek, J. Teichert
    HZDR, Dresden, Germany
  
  Funding: We acknowledge the support of the European Community-Research Infrastructure Activity (EuCARD, contract number 227579), as well German Federal Ministry of Education and Research grant 05 ES4BR1/8.
Since 2005 the photocathode laboratory has been in operation at HZDR. The main goal is to prepare Cs2Te photocathodes for the SRF gun. A vacuum transport system with UHV is used to move the cathodes from preparation lab to accelerator hall. Up to now 31 Cs2Te photocathodes have been deposited and eight of them have been used in the SRF gun. Quantum efficiency of 1% and lifetime of months can be maintained during the gun operation. At the same time activities are directed towards new photocathode materials with high Q.E. for high current electron sources. Cs3Sb and GaN(Cs) photocathodes have been tested as new candidates, and the design of a preparation system for GaAs(Cs, O) is ongoing. 		 
 
TUPPD066 Lifetime Studies of Cs2Te Cathodes at the PHIN RF Photoinjector at CERN cathode, gun, laser, beam-losses 1554
 
  • C. Heßler, E. Chevallay, M. Divall Csatari, S. Döbert, V. Fedosseev
    CERN, Geneva, Switzerland
  
  The PHIN photoinjector has been developed to study the feasibility of a photoinjector option for the CLIC (Compact LInear Collider) drive beam as an alternative to the baseline design, using a thermionic gun. The CLIC drive beam requires a high charge of 8.4 nC per bunch in 0.14 ms long trains, with 500 MHz bunch spacing and 50 Hz macro pulse repetition rate, which corresponds to a total charge per macro pulse of 0.59 mC. This means unusually high peak and average currents for photoinjectors and is challenging with respect to the cathode lifetime. In this paper detailed studies of the lifetime of Cs2Te cathodes, produced by the co-evaporation technique, with respect to bunch charge, train length and vacuum level are presented. Furthermore, the impact of the train length and bunch charge on the vacuum level will be discussed and steps to extend the lifetime will be outlined.  
 
TUPPD067 Experimental Facility for Measuring the Electron Energy Distribution from Photocathodes electron, cathode, brightness, laser 1557
 
  • L.B. Jones, R.J. Cash, B.D. Fell, J.W. McKenzie, K.J. Middleman, B.L. Militsyn
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • H.E. Scheibler, A.S. Terekhov
    ISP, Novosibirsk, Russia
  
  ASTeC have spent several years developing a GaAs Photocathode Preparation Facility (PPF) which routinely produces cathodes with quantum efficiencies (Q.E.) up to 20% at 635 nm*. The goal is to use these cathodes in high-average-current high-brightness injectors for particle accelerators. Electron injector brightness is driven by photocathode emittance, and brightness will be increased significantly by reducing the longitudinal and transverse energy spread. We are constructing an experimental system for measurement of the horizontal and transverse energy spreads at room and LN2-temperature which accepts photocathodes from the PPF. The sample will be illuminated by a small, variable-wavelength light spot. The beam image will be projected onto a detector comprised of 3 grids which act as an energy filter, a micro-channel plate and a phosphor screen. A low-noise CCD camera will capture screen images, and the electron distribution and energy spread will be extracted through analysis of these images as a function of the grid potentials. The system will include a leak valve to progressively degrade the cathode, and thus allow its properties to be measured as a function of Q.E.
* Proc IPAC ’11, THPC129 (2011). 		 
 
TUPPD070 Kelvin Probe Studies of a Cesium Telluride Photocathode for the AWA Photoinjector cathode, electron, photon, wakefield 1566
 
  • E.E. Wisniewski, K.C. Harkay, Z.M. Yusof
    ANL, Argonne, USA
  • L.K. Spentzouris, J. Terry, D.G. Velazquez, E.E. Wisniewski
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for the new Argonne Wakefield Accelerator (AWA) to produce high charge per bunch (~50 nC). Here, we present a study of the "work function" of a cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the surprising effect of UV exposure on the work function, and the puzzling behavior of the work function during and after photocathode rejuvenation via heating.  
 
TUPPD071 Development of Cesium Telluride Photocathodes for the AWA Accelerator Upgrade wakefield, electron, acceleration, cathode 1569
 
  • Z.M. Yusof, M.E. Conde, W. Gai
    ANL, Argonne, USA
  • L.K. Spentzouris, E.E. Wisniewski
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: U.S. Department of Energy Office of Science under Contract No. DE-AC02-06CH11357.
Cesium telluride photocathodes have been fabricated for the Argonne Wakefield Accelerator (AWA) upgrade. The as-deposited photocathodes have consistently produced quantum efficiency values better than 10% with 254 nm light source and with variation of less than 5% over a circular area of 1.2 inches in diameter. We present various characterizations of the photocathode that have performed, including rejuvenation, lifetime, and performance in the L-band AWA photoinjector. 		 
 
TUPPD081 Development of Carbon NanoTube (CNT) Cathodes at RadiaBeam cathode, gun, high-voltage, electron 1590
 
  • L. Faillace, R.B. Agustsson, S. Boucher, A.Y. Murokh, A.V. Smirnov
    RadiaBeam, Santa Monica, USA
  
  RadiaBeam is developing Carbon Nanotube (CNT) cathodes for DC-pulsed and radio frequency (RF) driven electron sources. CNT cathodes, if realized, are capable of producing very high current density with low thermal emittance, due to ambient operating temperature. The initial experimental results of CNT cathodes are presented, including the high-voltage tests, and life time studies. CNT cathodes potential applications in accelerator science and microwave industry are discussed, and near term plans to test the CNT cathodes in the RF environment are presented.  
 
TUPPD083 Raising Photoemission Efficiency with Surface Acoustic Waves electron, photon, polarization, linac 1596
 
  • A. Afanasev, F. Hassani, C.E. Korman
    GWU, Washington, USA
  • V.G. Dudnikov, R.P. Johnson
    Muons, Inc, Batavia, USA
  • M. Poelker, K.E.L. Surles-Law
    JLAB, Newport News, Virginia, USA
  
  Funding: Supported in part by DOE STTR Grant DE-SC0006256. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
We are developing a novel technique that may help increase the efficiency and reduce costs of photoelectron sources used at electron accelerators. The technique is based on the use of Surface Acoustic Waves (SAW) in piezoelectric materials, such as GaAs, that are commonly used as photocathodes. Piezoelectric fields produced by the traveling SAW spatially separate electrons and holes, reducing their probability of recombination, thereby enhancing the photoemission quantum efficiency of the photocathode. Additional advantages could be increased polarization provided by the enhanced mobility of charge carriers that can be controlled by the SAW and the ionization of optically-generated excitons resulting in the creation of additional electron-hole pairs. It is expected that these novel features will reduce the cost of accelerator operation. A theoretical model for photoemission in the presence of SAW has been developed, and experimental tests of the technique are underway. 		 
 
TUPPP003 Status and Very First Commissioning of the ASTRID2 Synchrotron Light Source cavity, septum, dipole, synchrotron 1605
 
  • S.P. Møller, N. Hertel, J.S. Nielsen
    ISA, Aarhus, Denmark
  
  ASTRID2 is the new 10 nm UV and soft x-ray light source currently being built at Aarhus University, to replace the ageing source ASTRID. ASTRID2 is now in the end of its installation phase, with commissioning expected to take place during the spring. The status of the installation together with the first results of the commissioning will be presented.  
 
TUPPP009 Status of the PETRA III Upgrade undulator, shielding, radiation, site 1620
 
  • M. Bieler, K. Balewski, W. Drube, J. Keil, A. Kling
    DESY, Hamburg, Germany
  
  Since 2010 PETRA III, a third generation light source at DESY, has been running as a user facility, with all 14 undulator beam lines operational since autumn 2011. In order to fulfill the request for more beam time after the shut down of DORIS at the end of 2012, it was decided to add two additional halls at PETRA III, each housing 5 additional beam lines. Next to these two new halls about 100 m of the accelerator will be completely remodeled to install additional undulators. The upgrade should be accomplished during a 6 month shut down in 2013. In order to minimize this down time, it was decided to keep the existing accelerator tunnel in place. This has impact both on the mechanical connection between the accelerator and the experimental floor and on the design of the optical beam lines in the tunnel. In this paper the layout of the upgraded accelerator will be shown. The design status of the major components for the upgrade will be presented.  
 
TUPPP016 Recent Development of PF Ring and PF-AR undulator, injection, polarization, linac 1641
 
  • Y. Tanimoto, T. Aoto, S. Asaoka, K. Endo, K. Haga, K. Harada, T. Honda, Y. Honda, M. Izawa, Y. Kobayashi, A. Mishina, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, T. Nogami, T. Obina, T. Ozaki, C.O. Pak, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, K. Satoh, M. Shimada, K. Shinoe, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
  • H. Takaki
    ISSP/SRL, Chiba, Japan
  
  After the earthquake of March 11, two light sources of KEK, PF ring and PF-AR, have recovered the regular operation from October, 2011. We installed tandem variably-polarized undulators at PF ring in 2009. Recently, the orbit switching system has been completed with sufficient feed-forward orbit compensation at 10-Hz. PF ring is usually operated at 450 mA with a top-up injection using the pulsed sextupole magnet instead of the conventional kicker magnets. The transverse and longitudinal instabilities are suppressed by a digital feedback system using the iGp signal processor. In the longitudinal direction, we observed unstable quadrupole mode oscillation which could not be controlled by the feedback system. We had applied the phase modulation of the main RF cavity to stabilize the quadrupole oscillation before. Old-type RF-shielded gate valves damaged by the earthquake were removed from the ring during the summer maintenance. In the operation after autumn, the quadrupole oscillation can be cured by dividing the bunch train of partial-filling. Without the phase modulation, the effective brightness of SR beam has been improved especially at beam lines of finite dispersion function.  
 
TUPPP019 Overview of the Solaris Facility linac, storage-ring, klystron, dipole 1650
 
  • C.J. Bocchetta, M. Bartosik, P.P. Goryl, K. Królas, M. Młynarczyk, W. Soroka, M.J. Stankiewicz, P.S. Tracz, Ł. Walczak, A.I. Wawrzyniak, K. Wawrzyniak, J.J. Wiechecki, M. Zając, L. Zytniak
    Solaris, Kraków, Poland
  • R. Nietubyć
    The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland
  
  Funding: Work supported by the European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09
The Polish synchrotron light source Solaris is under construction in Kraków. The project is based on the MAX IV light source being built in Lund, Sweden. The 1.5 GeV storage ring for Solaris and part of the injector complex are identical to that of MAX IV, although both are housed in buildings that differ from those of MAX IV. Ground breaking on the green field site at the Jagiellonian University campus occurred at the start of 2012. A detail description of the facility infrastructure, services and construction choices is given together with the latest project developments for main accelerator systems. 		 
 
TUPPP023 Operation Status of ALBA Synchrotron Light Source storage-ring, feedback, emittance, kicker 1659
 
  • M. Pont
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
  
  ALBA is a 3.0 GeV third generation synchrotron light source which has been commissioned during 2011. From October 2011 up to 7 beamlines are delivering beam for beamline commissioning, 6 from insertion devices and 1 from a bending magnet. Since April 2012 the facility is open to external users. Beam current has been continuously increased and the present stored beam current for users is 200 mA in a multi-bunch filling pattern. Orbit stability is kept at ±1 micron with a slow orbit feedback. The paper will review the operation and performance status of the different subsystems and review also the main objectives for 2012: target current of 400 mA, delivery of 3000 hours of beam to beamlines, testing of a fast orbit feedback system as well as preparations for top-up operation.  
 
TUPPP024 Recent Progress on the MAX IV 1.5 GeV Storage Ring Lattice and Optics storage-ring, lattice, dipole, sextupole 1662
 
  • S.C. Leemann
    MAX-lab, Lund, Sweden
  
  Construction of the MAX IV facility started in 2010 and commissioning is expected to begin in 2014. Once completed, the facility will include two storage rings for the production of synchrotron radiation. The 3 GeV ring will house insertion devices for the production of x-rays, while the 1.5 GeV ring will serve UV and IR users. Recently, the lattice and optics of the 1.5 GeV storage ring have been modified as a result of detailed magnet and vacuum system design. This paper discusses the lattice and optics changes as well as their effects.  
 
TUPPP048 Increasing the Spectral Range of the CLIO Infrared FEL User Facility by Reducing Diffraction Losses undulator, FEL, laser, simulation 1709
 
  • J.-M. Ortega, G. Perilhous, R. Prazeres
    LCP/CLIO, Orsay, Cedex, France
  • H.B. Abualrob, P. Berteaud, L. Chapuis, M.-E. Couprie, T.K. El Ajjouri, F. Marteau, J. Vétéran
    SOLEIL, Gif-sur-Yvette, France
  • J.P. Berthet, F. Glotin
    CLIO/ELISE/LCP, Orsay, France
  
  Funding: CNRS/RTRA
The infrared free-electron laser offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to 1. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. At CLIO, we have obtained previously* an FEL tunable from 3 to 150 μm by operating the accelerator between 50 and 14 MeV. However, we found that a phenomenon of “power gaps“ is observed in far-infrared : the laser power falls down to zero at some particular wavelengths, whatever the beam adjustments are. We showed that this effect is related to to the waveguiding effect of the vacuum chamber leading to different losses and power outcoupling at different wavelengths**. To alleviate this effect we have designed a new undulator allowing to use a larger vacuum chamber without reducing the spectral tunability and agility of the FEL. From simulations, a large increase of available power is expected in far-infrared. The new undulator has been installed and its performances and first FEL measurement in far-infrared will be presented
* J.M. Ortega, F. Glotin, R. Prazeres
Infrared Physics and Technology, 49, 133 (2006)
** R. Prazeres, F. Glotin, J.-M. Ortega
Phys. Rev. STAB12, 010701 (2009)
 		 
 
TUPPR019 High Power Operation with Beam of a CLIC PETS Equipped with ON/OFF Mechanism recirculation, simulation, extraction, controls 1852
 
  • I. Syratchev, R. Corsini, A. Dubrovskiy, P.K. Skowroński
    CERN, Geneva, Switzerland
  • R.J.M.Y. Ruber
    Uppsala University, Uppsala, Sweden
  
  One of the feasibility issues of the CLIC two-beam scheme is the possibility of rapidly switching off the RF power production in individual Power Extraction and Transfer Structures (PETS) in case of breakdowns, either in the PETS or one of the main beam accelerating structures. The proposed solution is to use a variable external reflector connected to the PETS. When activated, this scheme allows us to manipulate gradually the RF power transfer to the accelerating structure and to reduce the RF power production in the PETS itself by a factor of 4. Recently the first operation of the Two Beam Test Stand (TBTS) PETS equipped with an on-off mechanism has been performed in CTF3. In this paper we will present the results of the PETS operation when powered by the drive beam up to high peak power levels (>100 MW) and compare them to expectations.  
 
TUPPR033 Improved Modelling of the Thermo-mechanical Behavior of the CLIC Two-Beam Module RF-structure, linac, alignment, simulation 1891
 
  • G. Riddone, T.O. Niinikoski, F. Rossi
    CERN, Geneva, Switzerland
  • R.J. Raatikainen, K. Österberg
    HIP, University of Helsinki, Finland
  • A. Samoshkin
    JINR, Dubna, Moscow Region, Russia
  
  The luminosity goal of the CLIC collider, currently under study, imposes micrometer mechanical stability of the 2-m-long two-beam modules, the shortest repetitive elements of the main linacs. These modules will be exposed to variable high power dissipation during operation resulting in mechanical distortions in and between module components. The stability of the CLIC module is being tested in laboratory conditions at CERN in a full-scale prototype module. In this paper, the revised finite element model developed for the CLIC two-beam module is described. In the current model, the structural behavior of the module is studied in more detail compared to the earlier configurations, in particular for what regards the contact modeling. The thermal and structural results for the module are presented considering the thermo-mechanical behavior of the CLIC collider in its primary operation modes. These results will be compared to the laboratory measurements to be done in 2012 with the full-scale prototype module. The experimental results will allow for better understanding of the module behavior and they will be propagated back to the present thermo-mechanical model.  
 
TUPPR054 Internal H0/H− Dump for the Proton Synchrotron Booster Injection at CERN booster, linac, radiation, injection 1942
 
  • M. Delonca, C. Maglioni, A.A. Patapenka, A. Sarrió Martínez
    CERN, Geneva, Switzerland
  
  In the frame of the LHC Injectors Upgrade Project at CERN (LIU), the new 160MeV H− Linac4 will inject into the four existing PS Booster rings after the conversion of H− into H+ in a stripping foil. Given a limited stripping efficiency and possible foil failures, a certain percentage of the beam is foreseen to remain partially (H0) or completely (H−) unstripped. An internal dump installed into the chicane magnet to stop these unstripped beams is therefore required. This paper presents the conceptual design of the internal dump, reviewing loading assumptions, design constraints, limitations and integration studies. Power evacuation through the thermal contact between the core and the external active cooling is addressed and, finally, results from the numerical thermo-mechanical analyses are reported.  
 
TUPPR062 The Conceptual Design of a Vacuum System for the ILC Damping Rings Incorporating Electron Cloud Mitigation Techniques wiggler, electron, photon, damping 1960
 
  • J.V. Conway, Y. Li, M.A. Palmer
    CLASSE, Ithaca, New York, USA
  
  Funding: Work Supported by DOE Award DE-SC0006505.
We describe the conceptual design of the vacuum system for the damping rings of the International Linear Collider. The design incorporates a range of techniques to suppress the development of the electron cloud (EC) in the positron ring. These techniques include coatings with low secondary electron yield (SEY), grooved chambers, clearing electrodes and antechambers for photoelectron control. The EC mitigation choices are based on the ILC Electron Cloud R&D program, which has been conducted at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) and at other collaborating institutions*. The conceptual designs for vacuum chambers in drifts, dipoles, wigglers and quadrupoles are presented.
* The International Linear Collider: A Technical Progress Report, E. Elsen et al., Eds., pp. 71-81 (2011).
 		 
 
TUPPR063 Investigation into Electron Cloud Effects in the ILC Damping Ring Design photon, wiggler, electron, lattice 1963
 
  • J.A. Crittenden, J.V. Conway, G. Dugan, M.A. Palmer, D. L. Rubin
    CLASSE, Ithaca, New York, USA
  • L.E. Boon, K.C. Harkay
    ANL, Argonne, USA
  • M.A. Furman
    LBNL, Berkeley, California, USA
  • S. Guiducci
    INFN/LNF, Frascati (Roma), Italy
  • M.T.F. Pivi, L. Wang
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the U.S. Department of Energy DE-SC0006506
We report modeling results for electron cloud buildup in the ILC damping ring lattice design. Updated optics, wiggler magnet, and vacuum chamber designs have recently been developed for the 5-GeV, 3.2-km racetrack layout. An analysis of the synchrotron radiation profile around the ring has been performed, including the effect of photon scattering on the interior of the vacuum chamber. Operational implications of the resulting electron cloud buildup will be discussed. 		 
 
TUPPR064 Time-resolved Shielded-Pickup Measurements and Modeling of Beam Conditioning Effects on Electron Cloud Buildup at CesrTA electron, photon, simulation, pick-up 1966
 
  • J.A. Crittenden, Y. Li, X. Liu, M.A. Palmer, S. Santos, J.P. Sikora
    CLASSE, Ithaca, New York, USA
  • S. Calatroni, G. Rumolo
    CERN, Geneva, Switzerland
  • S. Kato
    KEK, Ibaraki, Japan
  
  Funding: Work supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the U.S. Department of Energy DE-FC02-08ER41538.
The Cornell Electron Storage Ring Test Accelerator program includes investigations into electron cloud buildup in vacuum chambers with various coatings. Two 1.1-m-long sections located symmetrically in the east and west arc regions are equipped with BPM-like pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. We present new measurements of the effect of beam conditioning on a newly-installed amorphous carbon coated chamber, as well as on a diamond-like carbon coating. The ECLOUD modeling code is used to quantify the sensitivity of these measurements to model parameters, differentiating between photoelectron and secondary-electron production processes. 		 
 
TUPPR065 Wiggler Magnet Design Development for the ILC Damping Rings wiggler, damping, lattice, linear-collider 1969
 
  • J.A. Crittenden, M.A. Palmer, D. L. Rubin
    CLASSE, Ithaca, New York, USA
  
  Funding: Work supported by the U.S. Department of Energy DE-SC0006506.
The baseline damping ring lattice design for the International Linear Collider employs nearly 60 2.2-m-long superconducting wiggler magnets to provide the damping necessary to achieve the specified horizontal emittance. We describe the OPERA-based finite-element model developed for the 14-pole, 30-cm period, 7.62-cm gap superferric design which meets the 2.1 T peak field requirement. Transfer functions and field uniformity results are discussed. We present results for the accuracy of the optimized analytic model needed for symplectic tracking algorithms, as well as implications for the updated engineering design. 		 
 
TUPPR090 Analysis of Ferrite Heating of the LHC Injection Kickers and Proposals for Future Reduction of Temperature kicker, injection, impedance, coupling 2038
 
  • M.J. Barnes, L. Ducimetière, N. Garrel, B. Goddard, V. Mertens, W.J.M. Weterings
    CERN, Geneva, Switzerland
  
  The two LHC injection kicker magnet (MKI) systems produce a kick of 1.3 T-m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen, consisting of a ceramic tube with conductors on the inner wall, is placed in the aperture of the magnets. The conductors provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against wake fields. The conductors initially used gave adequately low beam coupling impedance however inter-conductor discharges occurred during pulsing of the magnet; hence an alternative design was implemented to meet the often conflicting requirements for low beam coupling impedance, fast magnetic field rise-time and good high voltage behaviour. During 2011 the LHC has been operated with high intensity beam, coasting for many hours at a time, resulting in heating of both the ferrite yoke and beam impedance reduction ferrites, of the MKIs. This paper presents an analysis of thermal measurement data and an extrapolation of the heating for future operation; in addition means are discussed for reducing ferrite heating and improving cooling.  
 
TUPPR091 Status of the 160 MeV H− Injection into the CERN PSB injection, emittance, simulation, proton 2041
 
  • W.J.M. Weterings, B. Balhan, E. Benedetto, J. Borburgh, C. Bracco, C. Carli, B. Goddard, K. Hanke, B. Mikulec, A. Newborough, R. Noulibos, J. Tan
    CERN, Geneva, Switzerland
  
  The 160 MeV H− beam from the LINAC4 will be injected into the 4 superimposed rings of the PS Booster (PSB) with an new H− charge-exchange injection system. This entails a massive upgrade of the injection region. The hardware requirements and constraints, the performance specifications and the design of the H− injection region are described.  
 
TUPPR092 Transient Beam Losses in the LHC Injection Kickers from Micron Scale Dust Particles kicker, beam-losses, electron, injection 2044
 
  • B. Goddard, P. Adraktas, T. Baer, M.J. Barnes, F. Cerutti, A. Ferrari, N. Garrel, A.H.J. Gerardin, M. Guinchard, A. Lechner, A. Masi, V. Mertens, R. Morón Ballester, S. Redaelli, J.A. Uythoven, V. Vlachoudis, F. Zimmermann
    CERN, Geneva, Switzerland
  
  Transient beam losses on a time scale of a few ms have been observed in the LHC injection kickers, occurring mainly shortly after beam injection with a strong correlation in time to the kicker pulsing. The beam losses, which have at times affected LHC availability, are attributed to micron scale ceramic dust particles detached from the alumina beam pipe and accelerated into the beam. The beam related observations are described, together with laboratory measurements of beam pipe contamination and kicker vibration, simulations of electric field in the beam pipe and the basic dynamic model. Energy deposition simulations modelling the beam losses are presented and compared to measurement. Extrapolations to future LHC operation at higher intensities and energies are made, and prospects for mitigation are discussed.  
 
WEXB02 Diagnostics for High Power Targets and Dumps target, diagnostics, proton, radiation 2096
 
  • E. Gschwendtner
    CERN, Geneva, Switzerland
  
  High power targets and dumps are generally used for neutrino, antiproton, neutron and secondary beam production, or in waste management using intense beams. In order to guarantee an optimized and safe use of these targets and dumps, reliable instrumentation is needed; the diagnostics in high power beams around targets and dumps is reviewed. The suite of beam diagnostic devices used in such extreme environments is discussed, including their role in commissioning and operation. The handling and maintenance of the instrumentation components in high radiation areas will be addressed.  
slides icon Slides WEXB02 [13.010 MB]  
 
WEOAB02 Photocathode R&D at Cornell University electron, emittance, cathode, gun 2137
 
  • L. Cultrera, I.V. Bazarov, J.V. Conway, B.M. Dunham, Y. Hwang, Y. Li, X. Liu, R. Merluzzi, T.P. Moore, K.W. Smolenski
    CLASSE, Ithaca, New York, USA
  • S.S. Karkare, J.M. Maxson, W.J. Schaff
    Cornell University, Ithaca, New York, USA
  
  Funding: This work has been supported by NSF DMR-0807731 and by DOE DE-SC0003965.
A wide R&D program is pursued at Cornell University aimed at preparation and characterization of high efficiency photocathodes for the Energy Recovery Linac photoinjector. The currently investigated photoemitters include both positive and negative electron affinity materials such as respectively bi-alkali antimonide and III-V semiconductors activated with Cs and either O or F. Analysis techniques as Scanning Auger Spectroscopy, Low Energy Electron Diffraction, Reflected High Energy Electron Diffraction and work function measurements are used to characterize the surfaces properties of the specimens. Spectral response, photoemission uniformity, electron energy distributions are used to characterize the quality of the photoelectron beam and to relate it to the measured surface properties. 		 
slides icon Slides WEOAB02 [6.934 MB]  
 
WEEPPB007 Initial Testing of the Mark-0 X-band RF Gun at SLAC gun, solenoid, radiation, cathode 2179
 
  • A.E. Vlieks, C. Adolphsen, V.A. Dolgashev, J.R. Lewandowski, C. Limborg-Deprey, S.P. Weathersby
    SLAC, Menlo Park, California, USA
  
  A new X band RF Gun (Mark-0) has been assembled, tuned and is being tested in the ASTA facility at SLAC. This gun has been improved from an earlier gun used in Compton-scattering experiments at SLAC by the introduction of a racetrack dual-input coupler to reduce quadrupole fields. Waveguide-to-coupler irises were also redesigned to reduce surface magnetic fields and therefore peak pulse surface heating. Tests of this photocathode gun will allow us to gain early operational experience for beam tests of a new gun with further improvements (Mark-1) being prepared for SLAC’s X-Band Test Accelerator (XTA) program and the LLNL MegaRay program. Results of current testing up to ≈ 200 MV/m peak surface Electric fields will be presented.  
 
WEPPC001 Input Power Coupler for the IFMIF SRF Linac cryomodule, low-level-rf, SRF, controls 2200
 
  • H. Jenhani, P. Bosland, P. Carbonnier, N. Grouas, P. Hardy, V.M. Hennion, F. Orsini, J. Plouin, B. Renard
    CEA/IRFU, Gif-sur-Yvette, France
  • S.J. Einarson, T.A. Treado
    CPI, Beverley, Massachusetts, USA
  
  The design phase of the IFMIF-EVEDA Power Couplers for the Superconductive HWR has been accomplished. TiN and copper coatings specifications have been validated on samples. A coupler window equipped with a truncated antenna and RF matching transition have been fabricated and tested to qualify the manufacturing processes and to demonstrate the technical feasibility of the coupler. Series of tests were successfully performed on these subassemblies. The last part of the design phase consists of the design validation by manufacturing two coupler prototypes and testing their performances at full power. Finishing processes and validation tests are on-going.  
 
WEPPC012 High Power Tests of CW Input Couplers for cERL Injector Cryomodule cryomodule, cavity, linac, impedance 2230
 
  • E. Kako, S. Noguchi, T. Shishido, K. Watanabe, Y. Yamamoto
    KEK, Ibaraki, Japan
  
  High power tests of a pair of the prototype input couplers were performed by using a newly developed 300 kW CW klystron. The input couplers were successfully processed up to 100 kW in a pulsed operation with a duty of 10% and 50 kW in a CW operation for 30 minutes. The conditioning was limited by excessive heating at bellows of an inner conductor at a coaxial line locating between a coaxial RF window and a doorknob-type transition. Improvement of a sufficient cooling at the inner conductor is necessary to achieve the required input RF power of 170 kW in a CW operation. Six input couplers to be installed in the injector cryomodule for the cERL project were completed, and they are under preparation for conditioning at a high power test stand.  
 
WEPPC018 Design of a Spoke Cavity for RIKEN RI-beam Factory cavity, ion, simulation, heavy-ion 2245
 
  • L. Lu
    RIKEN, Saitama, Japan
  • O. Kamigaito, N. Sakamoto, K. Suda, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  
  Designs of a CW superconducting rebuncher tri-spoke cavity for uranium beams with β = 0.303 has been studied. The estimated peak voltage is rather high as 3 mega-voltages (MV). The resonator frequency was chose as 219MHz which is 12 times of the foundational frequency. The buncher would be settled in a location between two booster cyclotrons (RRC: K = 540MeV, fRC: K = 570 MeV). In this cavity design, a flat E field distribution on beam axis was designed based on the Microwave Studio (MWS) simulations. The cavity parameters, detail designs and some simulated results will be reported in this paper.  
 
WEPPC024 Preliminary Test of Superconducting RF Cavities for PLS-II SRF, cavity, cryomodule, cryogenics 2257
 
  • Y.U. Sohn, M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, I.H. Yu
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Funding: This project is supported by the Korea Ministry of Science and Technology.
The main part of the Installation for the PLS-II upgrade was finished in June and is on the way to user operation through elaborate commissioning. Up to now, the achievement is 150 mA beam current at 3 GeV with multi-bunch mode with 5 normal conducting cavities which served in the PLS before. After installation of 2 SRF cavities in the summer of 2012, the PLS-II will have 300 mA beam current with 20 IDs by 2 superconducting RF cavities until July, 2014. Finally, one more superconducting cavity will be added in August, 2014, and beam current will rise to 400 mA. The two SRF cavities are under test and conditioning. The two main subsystems, SRF cavities and ceramic windows were tested independently to confirm their performance. Each cavity recorded its accelerating voltage as 3.27 MV and 3.24 MV at 4.2K, respectively. Two RF windows also passed their specification, 300 kW CW traveling wave and 150 kW CW standing wave. The preliminary tests of SRF cryomodules are reported in the presentation. 		 
 
WEPPC035 Design and Construction of a High-Power RF Coupler for PXIE cryomodule, cavity, linac, simulation 2284
 
  • M.P. Kelly, Z.A. Conway, M. Kedzie, S.V. Kutsaev, P.N. Ostroumov
    ANL, Argonne, USA
  • S. Nagaitsev
    Fermilab, Batavia, USA
  
  A power coupler has been designed and built at Argonne National Laboratory for use with the Project X Injector Experiment (PXIE) 162.5 MHz superconducting (SC) half-wave cavities. The 50 Ω coaxial capacitive coupler will be required to operate CW with up to 10 kW of forward power under any condition for the reflected power. A key feature is a moveable copper plated stainless steel bellows which will permit up to 3 cm of axial stroke and adjustment of Qext by roughly one order of magnitude in the range of 10-5 to 10-6. The mechanical and vacuum design will include two ceramic windows, one operating at room temperature and another at 70 Kelvin. The two window design allows the portion of the coupler assembled to the SC cavity in the clean room to be compact and readily cleanable. We present other design features including thermal intercepts to provide a large margin for RF heating and a mechanical guide assembly to operate cold and under vacuum with high reliability.  
 
WEPPC036 Electromagnetic Design of 15 kW CW RF Input Coupler simulation, cavity, cryomodule, linac 2286
 
  • S.V. Kutsaev, M.P. Kelly, P.N. Ostroumov
    ANL, Argonne, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
A new power coupler is under development at Argonne National Laboratory for a cw 40 MeV proton/deuteron linac for the SARAF project in Israel. This linac requires one 15 kW RF input power per superconducting cavity. Two different cavity options are still under consideration: 109 MHz quarter-waves and 176 MHz half-waves. A coaxial capacitive input coupler has been designed and analyzed for these purposes. This paper presents the results of 3D electromagnetic simulations of this coupler together with the cavities mentioned above. An analysis of multipacting in the couplers is also presented. 		 
 
WEPPC040 Evaluation of VATSEAL Technology to Seal Waveguide Serving High-field Superconducting RF Cavities SRF, cavity, impedance, radio-frequency 2298
 
  • B.K. Stillwell, J.D. Fuerst, J. Liu, G.J. Waldschmidt, G. Wu
    ANL, Argonne, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A waveguide flange seal serving a high-field, superconducting, radio-frequency (SRF) cavity ideally possesses several characteristics. Seals must generally be ultrahigh-vacuum leak tight. Seals must also bridge the inner surfaces of connecting flanges for optimum transmission and minimal heating due to trapped modes. In addition, if seal contact areas are minimized, flange seals may serve as convenient thermal impedances. Finally, seals must be easily cleanable and not be prone to generate particulate matter during assembly and disassembly. A unique sealing technology known as VATSEAL may neatly address all of the above requirements. In this paper, we describe our evaluation of VATSEAL technology for use in SRF cavity assemblies. 		 
 
WEPPC041 Tests of SRF Deflecting Cavities at 2K cavity, SRF, cryogenics, photon 2300
 
  • J.D. Fuerst, D. Horan, J. Kaluzny, A. Nassiri, T.L. Smith, G. Wu
    ANL, Argonne, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) at Argonne National Laboratory (ANL) is developing 2.8-GHz deflecting-mode superconducting rf cavities in collaboration with Jefferson Lab as part of a major facility upgrade. On-site testing of these cavities requires a new cryostat capable of operation at 2.0 K or less. The APS has leveraged facilities and expertise within ANL’s Physics Division to upgrade an existing test stand for continuous operation at temperatures as low as 1.7 K. A new cryogenic feedbox was fabricated and mated to an existing liquid helium “bucket” dewar with 0.6-m inside diameter and 1-m working depth. The configuration allows continuous sub-λ operation using warm vacuum pumping and helium make-up from the Physics Division’s existing cryoplant at heat loads up to 50 W dynamic, plus 15 W measured static load at 2.0 K. A 2.8-GHz TWT-based rf station has been installed and commissioned, providing up to 275 W of rf power. We describe the cryogenic and rf performance of the system and provide examples of cavity test results. 		 
 
WEPPC050 Main Couplers for Project X cavity, radiation, linac, cryomodule 2324
 
  • S. Kazakov, M.S. Champion, S. Cheban, T.N. Khabiboulline, M. Kramp, Y. Orlov, V. Poloubotko, O. Pronitchev, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Design of 325MHz and 650MHz multi-kilowatt CW main couplers for superconducting linac of Project X is described. Results of electrodynamics, thermal and mechanical simulations is presented.  
 
WEPPC052 High Gradient Tests of the Fermilab SSR1 Cavity cavity, multipactoring, SRF, linac 2330
 
  • T.N. Khabiboulline, C.M. Ginsburg, I.V. Gonin, R.L. Madrak, O.S. Melnychuk, J.P. Ozelis, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, D.A. Sergatskov, A.I. Sukhanov, I. Terechkine, R.L. Wagner, R.C. Webber, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  In Fermilab we are build and tested several superconducting Single Spoke Resonators (SSR1, β=0.22) which can be used for acceleration of low beta ions. Fist two cavities performed very well during cold test in Vertical Test Station at FNAL. One dressed cavity was also tested successfully in Horizontal Test Station. Currently we are building 8 cavity cryomodule for PIXIE project. Additional 10 cavities were manufactured in the industry and ongoing cold test results will be presented in this poster.  
 
WEPPC058 Development at ANL of a Copper-brazed Joint for the Coupling of the Niobium Cavity End Wall to the Stainless Steel Helium Vessel in the Fermilab SSR1 Resonator niobium, cavity, coupling, SRF 2345
 
  • L. Ristori
    Fermilab, Batavia, USA
  • W.F. Toter
    ANL, Argonne, USA
  
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
In order to reduce the sensitivity of the Fermilab SSR1 resonator to helium pressure variations, it was concluded that the cavity and helium vessel end-walls needed to be structurally coupled by means of a transition ring. With the materials to be connected being Niobium and Stainless Steel, it was decided to utilize the same technology already developed for the cavity flanges which consists of a furnace-brazed joint utilizing oxygen-free electrolytic copper. Small-scale and full-scale annular samples have been constructed at Argonne National Laboratory and subject to tensile tests, thermal cycling and visual inspections to qualify the joint. The transition ring is electron-beam welded to the cavity and TIG welded to the helium vessel, the process is explained in detail. 		 
 
WEPPC065 Cleanroom Techniques to Improve Surface Cleanliness and Repeatability for SRF Coldmass Production SRF, cavity, superconductivity, controls 2357
 
  • L. Popielarski, L.J. Dubbs, K. Elliott, I.M. Malloch, R. Oweiss, J. Popielarski
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661 and Michigan State University.
The Facility for Rare Isotope Beams (FRIB) and ReA linear accelerator projects at Michigan State University (MSU) utilize Superconducting Radio-Frequency (SRF) cavities for their accelerating structures. The structures are cleaned and assembled in a cleanroom to reduce particle contamination. The project requires more than 350 SRF cavities. In preparation for production we want to maximize repeatable processes and reduce work time. The cleanroom assembly group at MSU investigates process techniques performed in the cleanroom. Various diagnostic tools; such as liquid particle counter, surface particle counter and airborne particle counter are used to quantify environments and optimize processes. We desire to define procedure specifications for cleaner processes and repeatability. We investigate effective part cleaning and storage, high pressure rinse and ultra pure water quality, and critical component rinsing. We study vacuum assembly, pump down and purge effects. The experiments are independent of cavity results with a focus to create cleanest surface and environment in the most effective manner. In this paper, we describe experiments, summarize the results and conclusions. 		 
 
WEPPC069 Construction, Evaluation, and Application of a Temperature Map for Multi-cell SRF Cavities cavity, SRF, controls, superconductivity 2369
 
  • G.M. Ge, F. Furuta, D.L. Hartill, K.M.V. Ho, G.H. Hoffstaetter, E.N. Smith
    CLASSE, Ithaca, New York, USA
  
  Temperature mapping (T-mapping) system is able to locate hot-spot of SRF cavity, thus it is a very powerful tool for cavity’s Q-value research. Recently Cornell University is developing a T-mapping system for multi-cell SRF cavities. The system includes more than two thousands Allen-Bradley resistors. Electronic of the system uses multiplexing of sensors which is able to dramatically reduce wire numbers, and allow the whole system is feasible for multi-cell cavity application. A new cavity testing insert which is for T-mapping system has been constructed.  
 
WEPPC082 First Results on Cornell TE-type Sample Host Cavities cavity, niobium, coupling, pick-up 2402
 
  • Y. Xie, M. Liepe
    CLASSE, Ithaca, New York, USA
  
  Funding: Work supported by NSF and Alfred P. Sloan Foundation.
In order to measure surface resistance of new materials other than niobium such as Nb3Sn and MgB2, two sample host niobium cavities operating at TE modes have been developed at Cornell University. The first one is a 6GHz pillbox TE011 cavity modified from an older vision enabling testing 2.75'' diameter flat sample plates. The second one is an optimized mushroom-shape niobium cavity operating at both 5GHz TE012 and 6GHz TE013 modes for 3.75'' diameter flat sample plates . First results from the commissioning of the two TE cavities will be reported. 		 
 
WEPPC097 Development of Nb and Alternative Material Thin Films Tailored for SRF Applications SRF, ion, ECR, plasma 2444
 
  • A-M. Valente-Feliciano, H.L. Phillips, C.E. Reece, J.K. Spradlin, X. Zhao
    JLAB, Newport News, Virginia, USA
  • B. Xiao
    The College of William and Mary, Williamsburg, USA
  
  Funding: *Authored by Jefferson Science Associates LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Avenues for the production of thin films tailored for Superconducting RF (SRF) applications are showing promise with recent developments in vacuum deposition techniques using energetic ions. JLab is using energetic condensation via Electron Cyclotron Resonance and High Power Impulse Magnetron Sputtering (HiPIMS) for the development of Nb films and multilayer SIS (superconductor-insulator-superconductor) structures to reach bulk Nb performance and beyond. Nb films with RRR comparable to bulk values are readily produced. The influence of the deposition energy on the material and RF properties of the Nb thin film is investigated with the characterization of their surface, structure, superconducting properties and RF response. Nucleation studies are investigating the best conditions to create a favorable template for growing the final SRF surface. This paper presents results on surface impedance measurements correlated with surface and material characterization for Nb and multilayered SIS films produced on a variety of substrates. 		 
 
WEPPC101 Characteristics and Fabrication of a 499 MHz Superconducting Deflecting Cavity for the Jefferson Lab 12 GeV Upgrade cavity, electron, target, niobium 2450
 
  • H. Park, S.U. De Silva
    JLAB, Newport News, Virginia, USA
  • J.R. Delayen
    ODU, Norfolk, Virginia, USA
  
  A 499 MHz parallel bar superconducting deflecting cavity has been designed and optimized for a possible implementation at the Jefferson Lab 12 GeV upgrade. This paper will present the analysis of the mechanical characteristics of the cavity (pressure sensitivity and tunability) and will detail the fabrication process. The unique geometry of the cavity–which is currently being fabricated at Jefferson Lab–and its required mechanical strength present interesting manufacturing challenges.  
 
WEPPC106 The First ASME Code Stamped Cryomodule at SNS cryomodule, linac, cavity, neutron 2465
 
  • M.P. Howell, D.R. Bruce, M.T. Crofford, D.L. Douglas, S.-H. Kim, S.E. Stewart, W.H. Strong
    ORNL, Oak Ridge, Tennessee, USA
  • R. Afanador, B.S. Hannah, J. Saunders
    ORNL RAD, Oak Ridge, Tennessee, USA
  • J.D. Mammosser
    JLAB, Newport News, Virginia, USA
  
  The first spare cryomodule for the Spallation Neutron Source (SNS) has been designed, fabricated, and tested by SNS personnel. The approach to design for this cryomodule was to hold critical design features identical to the original design such as bayonet positions, coupler positions, cold mass assembly, and overall footprint. However, this is the first SNS cryomodule that meets the pressure requirements put forth in the 10 CFR 851: Worker Safety and Health Program. The most significant difference is that Section VIII of the ASME Boiler and Pressure Vessel Code was applied to the vacuum vessel of this cryomodule. Applying the pressure code to the helium vessels within the cryomodule was considered. However, it was determined to be schedule prohibitive because it required a code case for materials that are not currently covered by the code. Good engineering practice was applied to the internal components to verify the quality and integrity of the entire cryomodule. The design of the cryomodule, fabrication effort, and cryogenic test results will be reported in this paper.  
 
WEPPC114 Design, Simulation and Conditioning of the Fundamental Power Couplers for BNL SRF Gun simulation, gun, SRF, klystron 2489
 
  • W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • M.D. Cole, G.J. Whitbeck
    AES, Medford, NY, USA
  
  Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 704 MHz SRF gun for the BNL Energy Recovery Linac (ERL) prototype uses two fundamental power couplers (FPCs) to deliver up to total 1 MW of CW RF power into the half-cell cavity. To prepare the couplers for high-power RF service and process multipacting, the FPCs should be conditioned prior to installation into the gun cryomodule. A room-temperature test stand was configured for conditioning FPCs in full reflection regime with varied phase of the reflecting wave. The FPCs have been conditioned up to 250 kW in pulse mode and 125 kW in CW mode. The multipacting simulations were carried out with Track3P code developed at SLAC. The simulations matched the experimental results very well. This paper presents the FPC RF and thermal design, multipacting simulations and conditioning of the BNL gun FPCs. 		 
 
WEPPC115 High Q0 in Superconducting Niobium Cavities: Progress at FNAL and Future Plans cavity, niobium, SRF, factory 2492
 
  • A. Grassellino, L.D. Cooley, C.M. Ginsburg, A. Romanenko, A.M. Rowe, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Consistent improvement in the quality factors of SRF cavities at medium surface fields of about 70 mT represents a direct cost savings factor for the proposed Project X CW linac and other SRF accelerator projects based on CW operation. Current state-of-the-art in SRF does not provide processing recipes to maximize the Q0 at those fields since a complete understanding of the mechanisms governing the quality factor at non-negligible surface fields is not yet developed. In this contribution we present results of the FNAL effort in both scientific understanding and practical improvements and discuss the directions we are pursuing for future research.  
 
WEPPC116 Depth Distribution of Losses in Superconducting Niobium Cavities cavity, niobium, SRF, positron 2495
 
  • A. Romanenko, A. Grassellino, J.P. Ozelis
    Fermilab, Batavia, USA
  • H. Padamsee
    CLASSE, Ithaca, New York, USA
  
  In order to optimize performances of superconducting niobium cavities it is crucial to understand the structure of near-surface few tens of nanometers of the material. In particular, superconducting properties of niobium, which depend on the presence of impurities and/or defects, may be non-uniform in the magnetic field penetration depth. A few cavity experiments based on oxypolishing* and anodizing**,*** provided some insight into the problem, but the definitive understanding is not developed yet. In this contribution we report on the "depth profiling" of the near-surface RF layer using an alternative technique based on the hydrofluoric acid (HF) rinsing. Tumbled, electropolished and buffered chemical polished cavities have been investigated and tentative nanostructural interpretation is discussed.
* P. Kneisel, Proc. of the 1999 SRF Workshop, Santa Fe, USA
** G. Eremeev and H. Padamsee, Physica C 441 No. 1-2 (2006) 62
*** G. Ciovati, P. Kneisel and A. Gurevich, PRSTAB 10 (2007) 062002 		 
 
WEPPD003 Development of a Condenser for the Helium Phase Separator at NSRRC simulation, cryogenics, synchrotron, synchrotron-radiation 2501
 
  • C.P. Liu, C.M. Cheng, F. Z. Hsiao, T.Y. Huang, H.H. Tsai
    NSRRC, Hsinchu, Taiwan
  
  A helium phase separator with a condenser is under fabrication and assembly at National Synchrotron Radiation Research Center (NSRRC). The objective of a helium phase separator with its condenser is to separate two-phase helium flow and to re-condense vaporized gaseous helium with a cryo-cooler of Gifford-McMahon type. This paper presents the design and fabrication of the condenser, a key component of the helium phase separator. A preliminary steady-state simulation of the efficiency of the helium condenser is also presented.
"Condenser","Rate of condensation" 		 
 
WEPPD005 SSR1 Cryomodule Design PXIE cryomodule, cavity, solenoid, cryogenics 2504
 
  • T.H. Nicol, S. Cheban, M. Chen, S. Kazakov, F. McConologue, Y. Orlov, D. Passarelli, V. Poloubotko, O. Pronitchev, L. Ristori, I. Terechkine
    Fermilab, Batavia, USA
  
  Funding: U.S. Department of Energy
Fermilab is planning to design and build a Project X Injector Experiment (PXIE), a cw linac, as a means of validating the Project X concept, reducing technical risks, and obtaining experience in the design and operation of a superconducting proton linac. The overall facility will include an ion source, low and medium-energy beam transport sections, a radio frequency quadrupole, and two cryomodules containing superconducting cavities. One will contain nine half-wave resonators operating at 162.5 MHz and six superconducting solenoids. The second will contain eight single spoke resonators (SSR1) operating at 325 MHz and four superconducting solenoids. This paper describes the design of the cryomodule being developed to house the 325 MHz single spoke resonators. Each of the main cryomodule systems will be described; cryogenic systems and instrumentation, cavity and solenoid positioning and alignment, conduction-cooled current leads, RF input couplers, magnetic shielding, cold-to-warm beam tube transitions, interfaces to interconnecting equipment and adjacent modules, as well as the overall assembly procedure. 		 
 
WEPPD006 Design of the FRIB Cryomodule cryomodule, cryogenics, alignment, solenoid 2507
 
  • M.J. Johnson, M. Barrios, J. Binkowski, S. Bricker, F. Casagrande, A.D. Fox, B.R. Lang, M. Leitner, S.J. Miller, T. Nellis, J.P. Ozelis, X. Rao, J. Weisend, Y. Xu
    FRIB, East Lansing, Michigan, USA
  • D. Arenius, V. Ganni, W.J. Schneider, M. Wiseman
    JLAB, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
An advanced, modular bottom-supported cryomodule design is described which is highly optimized for mass-production and efficient precision-assembly. The FRIB driver linac uses 4 types of superconducting resonators and 2 solenoid lengths which in turn require 7 individual cryomodule configurations. To meet alignment tolerances a precision-machined bolted cryomodule rail system is described. A novel, kinematic mounting system of the cold mass is introduced which allows for thermal contractions while preserving alignment. A first prototype will incorporate a wire position monitor for alignment verification. The cold alignment structure is supported by composite posts which also function as thermal isolators. The cryogenic system provides separate 2 K and 4.5 K liquid helium lines to cavities and solenoids. Details of the JT valves, heat exchanger, cool-down circuit and junction to cryogenic line will be provided. Transient cool-down was simulated for stresses and buckling failure. A 1100-O Aluminum shield is used as a thermal radiation shield. The paper also describes cryomodule interfaces with the linac tunnel, the RF input cables, and the cryogenic distribution system.
Michigan State University designs and establishes FRIB as a DOE Office of Science National User Facility in support of the mission of the Office of Nuclear Physics. 		 
 
WEPPD007 Integrated Thermal Analysis of the FRIB Cryomodule Design cryomodule, cryogenics, simulation, radiation 2510
 
  • Y. Xu, M. Barrios, F. Casagrande, M.J. Johnson, M. Leitner
    FRIB, East Lansing, Michigan, USA
  • D. Arenius, V. Ganni, W.J. Schneider, M. Wiseman
    JLAB, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Thermal analysis of the FRIB cryomodule design is performed to determine the heat load to the cryogenic plant, to minimize the cryogenic plant load, to simulate thermal shield cool down as well as to determine the pressure relief sizes for failure conditions. Static and dynamic heat loads of the cryomodules are calculated and the optimal shield temperature is determined to minimize the cryogenic plant load. Integrated structural and thermal simulations of the 1100-O aluminium thermal shield are performed to determine the desired cool down rate to control the temperature profile on the thermal shield and to minimize thermal expansion displacements during the cool down. Pressure relief sizing calculations for the SRF helium containers, solenoids, helium distribution piping, and vacuum vessels are also described.
Michigan State University designs and establishes FRIB as a DOE Office of Science National User Facility in support of the mission of the Office of Nuclear Physics. 		 
 
WEPPD010 Re-commissioning of the ESRF Storage Ring Vacuum System storage-ring, synchrotron, insertion, insertion-device 2516
 
  • M. Hahn, I. Parat
    ESRF, Grenoble, France
  
  A long shutdown of the accelerators to allow the construction of new buildings marked the phase one of the ESRF upgrade program. A number of vacuum sectors has been modified during this time for repair and maintenance but mainly to increase the brilliance of the synchrotron radiation beams by installing longer insertion device (ID) vessels with non-evaporable getter (NEG) coating and a new In Vacuum Undulator. The paper gives an overview of the modified machine and reports experience with its re-conditioning.  
 
WEPPD011 Study of the Pressure Profile Inside the NEG Coated Chambers of the SIS 18 dipole, simulation, quadrupole, ion 2519
 
  • M.C. Bellachioma, H. Kollmus, A. Krämer, J. Kurdal, H. Reich-Sprenger, L. Urban, M. Wengenroth
    GSI, Darmstadt, Germany
  
  In the context of the technical developments for the construction of FAIR at GSI, an intensive programme for the vacuum upgrade of the existing SIS 18 was started in 2005, with the aim to improve the beam lifetime and intensity. To reach these purposes also the installation of NEG coated dipole and quadrupole chambers is foreseen. During the upgrade shutdowns performed between 2006 and 2009 the vacuum chambers of approximately 65% of the SIS18 circumference were replaced by NEG coated pipes. To evaluate in detail the pressure profile inside the coated chambers mounted into the accelerator a dedicated experimental set-up, which reproduces a vacuum environment similar to the one of the SIS 18, was built. Using three gauges, mounted in different positions of a coated chamber, it was possible to measure the pressure in the range of 10-12 mbar inside the activated NEG pipe and 10-11 mbar outside the pipe at the pumping posts. Additionally, a modelling of a SIS18 vacuum sector was realised and the pressure variation values obtained by a Monte-Carlo simulation were compared with those measured. In this paper the experimental results and the vacuum simulations are described and discussed.  
 
WEPPD013 Status of the Vacuum System in J-PARC RCS ion, proton, site, electron 2522
 
  • J. Kamiya, Y. Hikichi, M. Kinsho, M. Nishikawa, N. Ogiwara, T. Yanagibashi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  In the vacuum system of J-PARC Rapid cycling synchrotron (RCS), we use beam pipes and bellows whose materials are vacuum fired at 700~850 oC in order to eliminate atoms in their bulk who are origin of outgassing. Until now, beam power has been increased up to 300 kW. Pressure in synchrotron beam line increased when the high power beam was accelerated. However, increment of pressure has reduced during the continuous beam operation. It is because the molecules, which adsorb on surface of the wall of the vacuum chambers, desorb by an ion bombardment and a heat generation due to an eddy current. Because the atoms in the bulk is eliminated, desorption of the molecules, which adsorb on the surface, means the reduction of the outgassing from the wall. In this presentation, we will report the past situation of the vacuum system during the beam operation. In addition, we also show the status after the Great East Japan Earthquake.  
 
WEPPD015 Saturation Behaviour of the LHC NEG Coated Beam Pipes simulation, injection, site, insertion 2525
 
  • G. Bregliozzi, V. Baglin, J.M. Jimenez, G. Lanza, T. Porcelli
    CERN, Geneva, Switzerland
  
  In the CERN Large Hadron Collider (LHC), about 6 km of the UHV beam pipe are at room temperature and serve as experimental or utility insertions. TiZrV non-evaporable getter (NEG) coating is used to maintain the design pressure during beam operation. Molecular desorption due to dynamic effects is stimulated during protons operation at high intensity. This phenomenon produces an important gas load from the vacuum chamber walls which could lead to a partial or total saturation of the NEG coating. To keep the design vacuum performances and to schedule technical interventions for NEG re-activation, it is necessary to take in account all these aspects and to regularly evaluate the saturation level of the NEG coating. Experimental studies in a typical LHC vacuum sector were conducted in order to identify the best method to assess the saturation level of the beam pipe. Partial saturation of the NEG was performed and the effects in the variations of pressure reading, effective pumping speed, transmission and capture probability are analysed. Finally, based on these results, a detailed analysis of the NEG coating saturation level of some area of the LHC is presented and analysed.  
 
WEPPD016 Development of Glassy Carbon Blade for LHC Fast Vacuum Valve acceleration, kicker, synchrotron, synchrotron-radiation 2528
 
  • C. Garion, P. Coly
    CERN, Geneva, Switzerland
  
  An unexpected gas inrush in a vacuum chamber leads to the development of a fast pressure wave. It carries small particles that can compromise the functioning of sensitive machine systems such as the RF cavities or kickers. In the LHC machine, it has been proposed to protect these equipments by the installation of fast vacuum valves. The main requirements for the fast valves and in particular for the blade are: fast closure in the 20 ms range, high transparency and melting temperature in case of closure with beam in, dust free material to not contaminate sensitive adjacent elements and last but not least vacuum compatibility and adequate leak tightness across the blade. In this paper, a design based on a vitreous carbon blade is proposed. The main reasons for this material choice are given. The mechanical study of the blade behaviour under dynamic forces is shown. Fabrication considerations are addressed as well. Tests on prototypes have been carried out on pendulum type fast valves developed for LEP. Results on glassy carbon blades are presented as well as the motion parameter measurements. Qualification of the material for UHV applications has been carried out.  
 
WEPPD017 Development of a New RF Finger Concept for Vacuum Beam Line Interconnections impedance, linac, higher-order-mode, simulation 2531
 
  • C. Garion, A. Lacroix, H. Rambeau
    CERN, Geneva, Switzerland
  
  RF contact fingers are primarily used as a transition element to absorb the thermal expansion of vacuum chambers during bake-out and also to compensate for mechanical tolerances. They have to carry the beam image current to avoid the generation of Higher Order Modes and to reduce beam impedances. They are usually made out of copper beryllium thin sheets and are therefore very fragile and critical components. In this paper, a robust design based on a deformable finger concept is proposed. It allows the compensation of large longitudinal movements and also defaults such as transverse offset, twist or bending. The concept of this new RF fingers is first explained, then the design of the component is presented. The mechanical study based on a highly non linear Finite Element model is shown as well as preliminary tests, including fatigue assessment, carried out on prototypes.  
 
WEPPD018 LHC Beam Vacuum During 2011 Machine Operation electron, kicker, injection, proton 2534
 
  • G. Lanza, V. Baglin, G. Bregliozzi, J.M. Jimenez
    CERN, Geneva, Switzerland
  
  During the year 2011 the LHC operated for 682 fills, meaning 247 days and 2 hours of stable beam in total. From 368 bunches per beam at 150 ns bunch spacing circulating in the ring in December 2010, the 2011 proton physic ended with 1380 bunches per beam circulating with 50 ns bunch spacing. The machine performances increased in parallel with the vacuum improvement thanks to a well performed scrubbing run in April 2011 and a continuous conditioning of the beam pipes while the machine was running. The 2011 LHC operation ended with one month of ions physic runs. During the machine operation various phenomena of beam - vacuum interaction were detected, analyzed and solved. This paper describes the pressure behavior along the machine layout and mainly in specific components position like TDI and MKI. The “pressure spike” phenomena near the experiment CMS and in some Dipole 1 (D1) regions are discussed. Finally, results obtained during the 25 ns machine developments are presented.  
 
WEPPD019 Manufacturing and Welding Process of Straight Section of Aluminum Alloy UHV Chambers for Taiwan Photon Source photon, synchrotron, radiation, synchrotron-radiation 2537
 
  • C.-C. Chang, C.K. Chan, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu
    NSRRC, Hsinchu, Taiwan
  
  This paper describes the manufacturing process and welding sequence for the aluminum extrusion vacuum chamber for the straight sections in Taiwan Photon Source. The straight section composes of aluminum extrusion chamber of A6063 and BPM chamber of A6061 aluminum alloys. The straightness and flatness of these extrusion chambers are controlled under 0.1mm/m and 0.2mm/m, respectively. The BPM chambers are manufactured precisely in oil-free environment, which provide clean surface and a precise sealing surface after machining. All the components are assembled in pre-aligned support system through the welding process. The aluminum chamber for 24 straight sections has been welded. The results show the straightness of < 0.15mm/m, flatness of < 0.3mm/m, and leakage rates of < 2 × 10-10 mbarl/sec. were achieved.  
 
WEPPD020 Vacuum System for TPS Booster booster, lattice, ion, electron 2540
 
  • C.M. Cheng, C.K. Chan, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu, H.P. Hsueh
    NSRRC, Hsinchu, Taiwan
  
  The TPS booster is designed for lower beam emittance and 3GeV full energy injection ramped up from 150MeV. It is a synchrotron accelerator of 496.8m in circumference and located concentric with the electron storage ring in the same tunnel. The vacuum system for the booster is divided into six super periods and each has nine bending magnet chambers. The beam duct is made of thin stainless steel tube extruded to the elliptical cross section with inner diameters of 35 mm×20 mm and thickness of 0.7 mm. All the chambers will be supported on the inner wall of the tunnel. The straightness of the extruded thin chambers is controlled within 2.5 mm in 4 m length. The bending chamber is made by mechanical bending from the straight tube. All the beam ducts will be chemical cleaned prior to welding, with flanges or BPM chambers, to form the long chambers in the clean room before installation. The arrangement of vacuum pumps are distributed to fulfill an average pressure of ＜1×10-6 Pa. The detailed design and the construction status will be described in the paper.  
 
WEPPD021 Optimization of the Ultra-High Vacuum Systems for the 3 GeV TPS Synchrotron Light Source impedance, photon, electron, synchrotron 2543
 
  • G.-Y. Hsiung, C.K. Chan, C.-C. Chang, C.L. Chen, J.-R. Chen, C.M. Cheng, Y.T. Cheng, S-N. Hsu, H.P. Hsueh, Huang, Y.T. Huang, I.C. Sheng, L.H. Wu, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
  
  The Taiwan Photon Source (TPS), a 3 GeV synchrotron light source, provides an ultra-low emittance of electron beam and the consequent extremely high brightness of photons. The vacuum pressure along the beam duct should be ultra-high vacuum (UHV) and even lower for reduction of the impact to the beam from the gas scattering or ion trapping troubles. Most of the outgas comes from the photon stimulated desorption (PSD) back streaming from downstream absorbers during beam operation and large area surface outgas inside the beam duct as well. Due to the anticipate request of the smallest vertical aperture of beam ducts from various insertion devices and the lowest broadband impedance through all the vacuum chambers of electron storage ring, the inner structure design and the surface treatment of vacuum chambers as well as the constraint of the back stream PSD outgas from distributed absorbers and the pumping locations should be optimized to obtain a high quality UHV system for the high stable synchrotron light source through the long period of operation. The optimized design of the vacuum chambers for the TPS will be described.  
 
WEPPD022 Design of the Water-Cooling System for the Vacuum System of the TPS Storage Ring synchrotron, storage-ring, photon, controls 2546
 
  • Y.C. Yang, C.K. Chan, J.-R. Chen, C.M. Cheng, G.-Y. Hsiung
    NSRRC, Hsinchu, Taiwan
  
  Taiwan Photon Source (TPS) was under construction since 2009. TPS vacuum system was designed in 10-10 torr level and gas load from synchrotron light was almost confined in bending chambers. A water cooling system was designed to protect vacuum equipment including vacuum chambers and absorbers to avoid melting down by synchrotron light. There are 3 cooling loops for aluminum chambers and 4 loops for cooper absorbers in one unit cell. One prototype for unit cell, including arrangement of control terminal, monitor of flow rate and temperature, and vibration from cooling system will be tested.  
 
WEPPD023 Design and Manufacture of TPS BPM Diamond-Edge Gasket synchrotron, factory 2549
 
  • Huang, Y.T. Huang, C.-C. Chang, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, H.P. Hsueh
    NSRRC, Hsinchu, Taiwan
  
  TPS vacuum chamber is oil-free machined and the material is A6061T651 which the Brinell hardness is 95 kg/mm2. Beam position monitors are installed onto the bending chambers, B1 and B2 and the straight chambers, S3 and S4. The diamond-edge gasket was chosen to seal between BPM flange (SS316L) and the vacuum chamber (A6061T651). Easily manufactured, low cost and less clamping force are three main advantages of this diamond-edge gasket. This diamond-edge gasket is made of A1050H14 which has less hardness, 32 kg/mm2 and its surface roughness is well controlled under 0.8 μm because worse surface roughness probably lead to radial leak. Considering differences of thermal expansion between stainless steel and aluminium, SS304 set screws, nuts and washers are chosen to provide axial sealing force. The sealing ability of this diamond-edge gasket is reliable through tens of bake-out experiments. It is reminded that pre-torque should be sufficient to cause plastic deformation of the diamond-edge gasket and re-torque after baking 24hr and cooling down to room temperature is also important to prevent leaks resulting from loss of torque which usually happen at 100oC.  
 
WEPPD024 A Study of Vacuum Pressure in TPS Cells photon, site, electron, controls 2552
 
  • L.H. Wu, J.-R. Chen, C.M. Cheng, G.-Y. Hsiung, C.S. Huang, Huang, Y.T. Huang
    NSRRC, Hsinchu, Taiwan
  
  Recently, the type-2 and type-3 TPS cells are installed and pumped down into vacuum status. The pumping down curves of the type-2 and type-3cells, including R03, R06, R07, R10, and R11, are recorded after on-site welding and after assembling without leakage, individually. In the R03, R06, R07, R10 cells, the pumping down curve after assembling without leakage is a little higher than that after on-site welding. In those four cells, the pumping down curve after assembling all vacuum components and pumps is similar. However, in the R11 cell, it was found that the pumping down curve after assembling without leakage is almost along that of after on-site welding. The slope of pumping down curve near 1 hour in the R11 cell is -1.52, while that in the R10 cell is -1.39. It means that the vacuum pressure in the R11 cell is apparently improved. It is confirmed that the vacuum chambers are cleaned by the same process and the assembling components are similar. Besides, the photon stopper chambers are all pre-baked to 200 oC for the same time. We try to investigate the residual gas analysis (RGA) data to find the true reasons.  
 
WEPPD025 LHC Detector Vacuum System Consolidation for Long Shutdown 1 (LS1) in 2013-2014 ion, background, radiation, electron 2555
 
  • M.A. Gallilee, J. Chaure, P. Cruikshank, J.E. Gallagher, C. Garion, J.M. Jimenez, R. Kersevan, H. Kos, L. Leduc, P. Lepeule, N. Provot, H. Rambeau, R. Veness
    CERN, Geneva, Switzerland
  
  The LHC has ventured into unchartered territory for Particle Physics accelerators. A dedicated consolidation program is required between 2013 and 2014 to ensure optimal physics performance. The experiments, ALICE, ATLAS, CMS, and LHCb, will utilise this shutdown, along with the gained experience of three years of physics running, to make optimisations to the detectors. New vacuum technologies have been developed for the experimental areas, to be integrated during this first phase shutdown. These technologies include bellows, vacuum chambers and ion pumps in aluminium, new beryllium vacuum chambers, and composite mechanical supports. An overview of this first phase consolidation program for the LHC experiments is presented.  
 
WEPPD026 Design and Fabrication of NSLS-II Storage Ring Vacuum Chambers and Components storage-ring, photon, multipole, impedance 2558
 
  • H.-C. Hseuh, A.T. Anderson, L. Doom, M.J. Ferreira, C. Hetzel, C. Longo, V. Ravindranath, K. Roy, S.K. Sharma, J.L. Tuozzolo, K. Wilson
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work performed under the auspices of U.S. Department of Energy, under contract DE-AC02-98CH10886
The National Synchrotron Light Source II, a 3-GeV, 792-meter circumference, synchrotron radiation facility with ultra-high-flux and –brightness, is under construction at Brookhaven National Laboratory. The storage ring vacuum chambers are mainly made of extruded aluminium but with a few made of stainless steel and inconel. The synchrotron radiation from bending magnets is intercepted at discrete photon absorbers made of GlidCop. NEG strips in the ante-chamber provide the distributed pumping, while lumped ion pumps and titanium sublimation pumps at photon absorbers remove the desorbed gas. The complex vacuum system is being assembled and integrated in-house. This paper describes the design and fabrication of both standard and special vacuum chambers, the low impedance RF shielded bellows and the photon absorbers. The vacuum system is now moving into the conditioning, installation and testing phase. Details and experience from the large scale production, testing and lesson learned will also be presented. 		 
 
WEPPD029 The Mechanical Design of a Collimator and Cryogenic Bypass for Installation in the Dispersion Suppressors of the LHC cryogenics, superconducting-magnet, shielding, collimation 2567
 
  • D. Ramos, L. Alberty Vieira, A. Bertarelli, A. Cherif, N. Chritin, R. Claret, L. Gentini, D. Lombard, P. Minginette, P. Moyret, M. Redondas Monteserin, T. Renaglia, M.A. Timmins
    CERN, Geneva, Switzerland
  
  A project to install collimators in the dispersion suppressor regions of the LHC was launched early 2010, aiming to reduce the power deposition in superconducting magnets by a factor of 10. To be placed in the continuous arc cryostat, the design of such collimators had to comply with challenging integration, functional and time constraints. A pre-study for a cold collimator solution was launched in parallel with an alternative design consisting of a room temperature collimator and a cryogenic bypass. The second was eventually preferred, as it was based on proven LHC technologies for cryogenic, vacuum, electrical and collimator material solutions, despite the increased difficulty on the mechanical integration and assembly. This paper presents the mechanical design of a cryogenic bypass for the LHC continuous cryostat and respective collimator unit, both made to comply with the functionality of existing LHC systems. The approach taken to achieve a reliable design within schedule will be explained alongside the measures adopted to validate new solutions, in particular, when dealing with welding distortions, systems routing, thermal loads and precision mechanics.  
 
WEPPD035 Design Considerations for an MEBT Chopper Absorber of 2.1MeV H− at the Project X Injector Experiment at Fermilab ion, cryomodule, radiation, neutron 2585
 
  • C.M. Baffes, M.H. Awida, A.Z. Chen, Y.I. Eidelman, V.A. Lebedev, L.R. Prost, A.V. Shemyakin, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
The Project X Injector Experiment (PXIE) will be a prototype of the Project X front end that will be used to validate the design concept and decrease technical risks. One of the most challenging components of PXIE is the wide-band chopping system of the Medium Energy Beam Transport (MEBT) section, which will form an arbitrary bunch pattern from the initially CW 162.5 MHz 5mA beam. The present scenario assumes diverting 80% of the beam to an absorber to provide a beam with the average current of 1mA to SRF linac. This absorber must withstand a high level of energy deposition and high ion fluence, while being positioned in proximity of the superconductive cavities. This paper discusses design considerations for the absorber, including specific challenges as spreading of energy deposition, management of temperatures and temperature-induced mechanical stresses, radiation effects, surface effects (sputtering and blistering), and maintaining vacuum quality. Thermal and mechanical analyses of a conceptual design are presented, and future plans for the fabrication and testing of a prototype are described. 		 
 
WEPPD046 Design of Machine Protection System for the Taiwan Photon Source EPICS, controls, storage-ring, status 2618
 
  • C.Y. Liao, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.H. Kuo, D. Lee, C.Y. Wu
    NSRRC, Hsinchu, Taiwan
  
  The Taiwan Photon Source (TPS) is being constructed at the campus of the NSRRC (National Synchrotron Radiation Research Center). In order to prevent damage to accelerator components induced by various events, design of the global machine protection system (MPS) is on-going. The MPS collect interlock and beam dump request from various system, perform decision, transmit dump beam request to RF system. The PLC based system will be used as a slow MPS which can delivery less than 8 msec reaction time. The fast MPS will dependent on event based timing system to deliver response time less than 5 μsec. Trigger signal for post-mortem will also be distributed by the fast MPS. To ensure alive of the system, several self-diagnostics mechanisms include heartbeat and transient capture will be implemented. The MPS architecture, plans and implementation were presented in this report.  
 
WEPPD054 Development of Pulsed Laser Systems and Cathode-performance Studies for the S-DALINAC Polarized Injector laser, cathode, electron, cavity 2642
 
  • M. Espig, C. Eckardt, J. Enders, Y. Fritzsche, N. Kurichiyanil, J. Lindemann, M. Wagner
    TU Darmstadt, Darmstadt, Germany
  
  A source of polarized electrons has recently been implemented at the superconducting Darmstadt electron linear accelerator S-DALINAC. We give an overview of the recent performance of the system. Photo-emission from a superlattice-GaAs photo-cathode is obtained from using either a DC diode laser or a short-pulse Ti:Sapphire laser system. For a robust pulsed quasi-cw operation, it is investigated whether a VECSEL system (Vertical-Cavity Surface-Emitting Laser) can be realized with a wavelength of 780 nm and a repetition rate of 3 GHz with pulse widths of a few picoseconds only. To enhance the availability and performance of the polarized source with respect to quantum efficiency, a separate atomic-hydrogen cleaning system for the cathodes is planned which will allow cathode treatment to be tested and optimized. Supported by DFG within CRC/SFB 634 and by the state of Hesse in the LOEWE-Center HIC for FAIR.  
 
WEPPD062 Measurements of the First RF Prototype of the Spiral2 Single Bunch Selector impedance, high-voltage, scattering, simulation 2663
 
  • M. Di Giacomo
    GANIL, Caen, France
  • A.C. Caruso, F. Consoli, G. Gallo, D. Rifuggiato, E. Zappalà
    INFN/LNS, Catania, Italy
  • A. Longhitano
    ALTEK, San Gregorio (CATANIA), Italy
  
  Funding: Work supported by EU commission 7th framework project n. 212692.
The single bunch selector of the Spiral2 driver uses 100 Ω travelling wave electrodes driven by fast pulse generators. A 2.5 kV, 1 kW feed-through and a vacuum chamber housing the water cooled electrodes have been designed and built. The paper reviews the whole design and reports the results of first RF and power measurements. 		 
 
WEPPD064 Quick Recovery of the KEK e−/e+ Injector Linac from the Great East Japan Earthquake linac, injection, positron, electron 2669
 
  • A. Enomoto
    KEK, Ibaraki, Japan
  
  The KEK e−/e+ injector linac is under operation for the KEK Photon Factory (PF) storage ring and Photon Factory - Advanced Ring (PF-AR). And the linac has just started the upgrade for the SuperKEKB project. On March 11, the linac suffered great damage from the Great East Japan Earthquake. Due to an extraordinary strong vibration, many bellows of vacuum pipes were violently torn and the entire linac vacuum was exposed to the atmosphere. Without electricity, highly humid air entered the inside of accelerator structures. Some people supposed the linac would not be recovered within a year. However, it resumed operation after only two months. We report the memorable disaster and how we recovered the linac so quickly.  
 
WEPPD072 Frequency Fine-tuning of a Spin-flip Cavity for Antihydrogen Atoms cavity, resonance, antiproton, coupling 2690
 
  • S. Federmann, F. Caspers, E. Mahner
    CERN, Geneva, Switzerland
  • B. Juhasz, E. Widmann
    SMI, Vienna, Austria
  
  As part of the ASACUSA collaboration physics program a spin-flip cavity for measurements of the ground-state hyperfine transition frequency of anti-hydrogen atoms is needed. The purpose of the cavity is to excite anti-hydrogen atoms depending on their polarisation by a microwave field operating at 1.42 GHz. The delicacy of designing such a cavity lies in achieving and maintaining the required properties of this field over a large aperture of 10cm and for a long period of time (required amplitude stability is 1% within 12h). The present paper presents the frequency fine tuning techniques to obtain the desired centre frequency of 1.42 GHz with a Q value below 500 as well as the tuning circuit used for the frequency sweep over the desired bandwidth of 6 MHz.  
 
WEPPD078 Progress with PXIE MEBT Chopper kicker, simulation, radio-frequency, coupling 2708
 
  • V.A. Lebedev, A.Z. Chen, R.J. Pasquinelli, D.W. Peterson, G.W. Saewert, A.V. Shemyakin, D. Sun, M. Wendt
    Fermilab, Batavia, USA
  • T. Tang
    SLAC, Menlo Park, California, USA
  
  Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
A capability to provide a large variety of bunch patterns is crucial for the concept of the Project X serving MW-range beam to several experiments simultaneously. This capability will be realized by the Medium Energy Beam Transport’s (MEBT) chopping system that will divert 80% of all bunches of the initially 5mA, 2.1 MeV CW 162.5 MHz beam to an absorber according to a pre-programmed bunch-by-bunch selection. Being considered one of the most challenging components, the chopping system will be tested at the Project X Injector Experiment (PXIE) facility that will be built at Fermilab as a prototype of the Project X front end. The bunch deflection will be made by two identical sets of travelling-wave kickers working in sync. Presently, two versions of the kickers are being investigated: a helical 200 Ω structure with a switching-type 500 V driver and a planar 50 Ω structure with a linear ±250 V amplifier. This paper will describe the chopping system scheme and functional specifications for the kickers, present results of electromagnetic measurements of the models, discuss possible driver schemes, and show a conceptual mechanical design. 		 
 
WEPPD079 Measurements of Magnetic Permeability of Soft Steel at High Frequencies impedance, booster, dipole, damping 2711
 
  • Y. Tokpanov, V.A. Lebedev, W. Pellico
    Fermilab, Batavia, USA
  
  The Fermilab Booster does not have a vacuum chamber which would screen the beam from laminations its dipoles cores. Therefore the booster impedance is mainly driven by the impedance of these dipoles. Recently an analytical model of the laminated dipole impedances was developed. However to match the impedance measurements with calculations one needs an accurate measurement of soft steel magnetic permeability. This paper presents the measurement results of the permeability in a frequency range from ~10 MHz to 1 GHz. Measurements of e.-m. wave propagation in 30 cm long strip line built from soft steel were used to compute the permeability. Measurements were performed in a DC magnetic field to observe the effect of steel saturation on the high frequency permeability. Both real and imaginary parts of the permeability were measured. As expected their values were decreasing with frequency increase from 10 MHz to 1 GHz and with saturation of steel DC permeability.
Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. 		 
 
WEPPD082 Characterization of Photocathode Damage during High Current Operation of the Cornell ERL Photoinjector ion, gun, site, linac 2717
 
  • J.M. Maxson, S.S. Karkare
    Cornell University, Ithaca, New York, USA
  • I.V. Bazarov, S.A. Belomestnykh, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, K. Finkelstein, R.P.K. Kaplan, V.O. Kostroun, Y. Li, X. Liu, F. Löhl, B. Pichler, P. Quigley, D.H. Rice, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao
    CLASSE, Ithaca, New York, USA
  
  The Cornell ERL Photoinjector prototype has recently demonstrated successful operation at 20 mA for 8 hours using a bi-alkali photocathode grown on a Si substrate. The photocathode film was grown off center, and remained relatively undamaged; however, upon removal from the gun, the substrate at the gun electrostatic center displayed significant visible damage. Here we will describe not only the parameters of that particular high current run, but a suite of post-operation surface morphology and crystallographic measurements, including X-ray fluorescence, X-ray diffraction, contact profilometry, scanning electron microscopy, performed about the damage site and photocathode film. The data indicate violent topological changes to the substrate surface, as well as significant induced crystallographic strain. Ion back-bombardment is proposed as a possible mechanism for damage, and a simple model for induced crystal strain is proposed (as opposed to ion induced sputtering), and is shown to have good qualitative agreement with the spatial distribution of damage.  
 
WEPPP004 A Reciprocity Principle for Wakefields in a Two-Channel Coaxial Dielectric Structure wakefield, simulation, acceleration, dipole 2726
 
  • G.V. Sotnikov
    NSC/KIPT, Kharkov, Ukraine
  • J.L. Hirshfield, T.C. Marshall, G.V. Sotnikov
    Omega-P, Inc., New Haven, USA
  • S.V. Shchelkunov
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
  
  Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics.
The reciprocity principle* is often used in applications of classical electromagnetism. We have employed this principle for testing wakefields set up by an electron bunch in a two-channel coaxial dielectric structure (CDWA)**. For numerical studies we take a ~1-THz fused silica structure which we plan to test at FACET/SLAC; it has dimensions: outer shell, OD=800 μm, ID=500 μm; inner shell OD=181 μm, ID=50 μm. The structure is energized by a 23-GeV, 3-nC bunch having axial RMS size=25 μm. FACET has no drive bunch of annular shape as required for a CDWA; nevertheless, our analytical studies and simulations prove that for the axial wakefield, an annular drive bunch can be replaced by a pencil-like bunch of the same charge traveling in the annular vacuum channel. The longitudinal electric field along the accelerator channel axis (as recorded by a witness bunch) set up by this pencil-like bunch is the same as in the conventional structure of the CDWA. Moreover, if we interchange the drive bunch and the witness bunch, the witness bunch will register the same axial wakefield. However, the stability of the annular bunch is far superior to that of the pencil bunch.
*L. D. Landau and E. M. Lifshitz, Electrodynamics of Continuous Media (Addison-Wesley: Reading, MA, 1960).
**G. Sotnikov et al., PRST-AB, 061302 (2009).
 		 
 
WEPPP008 Vacuum Laser Acceleration Experiment Perspective at Brookhaven National Lab-Accelerator Test Facility laser, electron, acceleration, simulation 2735
 
  • X.P. Ding, D.B. Cline, L.S. Shao
    UCLA, Los Angeles, California, USA
  • M.G. Fedurin, K. Kusche, I. Pogorelsky, V. Yakimenko
    BNL, Upton, Long Island, New York, USA
  • Y.K. Ho, Q. Kong
    Fudan University, Shanghai, People's Republic of China
  • J.J. Xu
    Shanghai Institute of Optics and Fine Mechanics, Shanghai, People's Republic of China
  
  Funding: Supported by the DOE under award number DE-FG02-92ER40695 (UCLA)
This paper presents the pre-experiment plan and prediction of the first stage of Vacuum Laser Acceleration (VLA) collaborating by UCLA, Fudan University and ATF-BNL. This first stage experiment is a Proof-of-Principle to support our previously posted novel VLA theory. Simulations show that based on ATF’s current experimental conditions, the electron beam with initial energy of 15MeV can get net energy gain from intense CO2 laser beam. The difference of electron beam energy spread is observable by ATF beam line diagnostics system. Further this energy spread expansion effect increases along with the laser intensity increasing. The proposal has been approved by ATF committee and experiment will be the next project. 		 
 
WEPPP009 Experimental Progress Towards a Resonant Slab-symmetric Dielectric Laser Accelerator simulation, laser, electron, acceleration 2738
 
  • G. Travish, K.S. Hazra, G. Liu, J.C. McNeur, E.B. Sozer, J. Zhou
    UCLA, Los Angeles, California, USA
  • H. Hairong
    UESTC, Chengdu, Sichuan, People's Republic of China
  • R.B. Yoder
    Manhattanville College, Purchase, New York, USA
  
  Funding: Work funded in part by grant HDTRA1-09-1-0043 from the US Defense Threat Reduction Agency and under a grant from NNSA/NA-221 Office of Nonproliferation and Verification Research and Development.
TheμAccelerator Platform (MAP), a resonant dielectric structure for laser acceleration of electrons, has been in development for a number of years. It consists of a a vacuum gap between two slab-shaped reflecting boundaries, with a transmissive grating diffractive optic on one boundary that allows laser power to propagate into the gap and enforces an accelerating mode. We report on the progress of bench and beam tests carried out within the last year, and the challenges faced in diagnosing <pC beams from optical-scale structures. We also describe refinements to our fabrication techniques and lessons learned during the development of the fabrication process. 		 
 
WEPPP012 High-Gradient THz-Scale Two-Channel Coaxial Dielectric-Lined Wakefield Accelerator wakefield, acceleration, radiation, focusing 2747
 
  • S.V. Shchelkunov, M.A. LaPointe
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
  • J.L. Hirshfield, T.C. Marshall
    Omega-P, Inc., New Haven, USA
  • G.V. Sotnikov
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics.
A mm-scale THz Coaxial Dielectric Wakefield Accelerator structure is currently under study by Yale University Beam Physics Lab and collaborators for its performance with annular drive bunches. With our recent successful experiments with the cm-scale GHz rectangular module at AWA/Argonne (USA) and planned activity there with yet another cm-scale GHz coaxial structure, the program of new research has two objectives. The first is to design a structure to produce acceleration gradients approaching 0.35 GeV/m per each nC of drive charge when excited by an annular-like bunch; has an attractive feature that the drive and accelerated bunches both have good focusing and stability properties; and also exhibits a large transformer ratio. The second goal is to build and test the structure at FACET/SLAC (USA). At FACET the structure can be excited only with the available pencil-like drive bunch, but the reciprocity principle allows one to observe some of the properties that would be seen if the excitation were to be by an annular drive bunch. This presentation shows our latest findings, discusses related issues, and discusses our plans for experiments. 		 
 
WEPPP019 Designing of Photonic Crystal Accelerator for Radiation Biology laser, electron, injection, acceleration 2763
 
  • K. Koyama, Y. Matsumura
    University of Tokyo, Tokyo, Japan
  • A. Aimidula, M. Uesaka
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
  • T. Natsui, M. Yoshida
    KEK, Ibaraki, Japan
  
  Funding: This work was performed as part of the Global COE Program (Nuclear Education and Research Initiative, MEXT, Japan.
A photonic crystal accelerator with a combination of a fiber laser is under development in order to apply it to the radiation biology. In order to investigate fundamental biological processes in a cell, a DNA is precisely shot by an electron bunch with an in situ observation of a radiation interaction using a microscope. Required beam diameter, bunch length, and beam energy are nanometer, attosecond, and 100 keV to 1 MeV, respectively. A photonic crystal or dielectric laser accelerator energized by a fiber laser is suitable for producing such a fine beam with a palm top device. A preliminary estimation shows that 200 keV electron bunch is available from a 0.8-mm-long accelerator and a few cm electron gun, which is driven by a few μJ, 5-ps laser pulse. We are developing a fiber laser in order to drive the photonic crystal accelerator. The Yb-fiber oscillator delivers mode-locked pulse train of ≈5 nJ/pulse at the repetition frequency of 62.5 MHz. The output pulse will be increased to several μJ by adopting a fiber amplifier 		 
 
WEPPP023 Radiation of a Bunch Intersecting a Boundary between Vacuum and Dielectric in a Circular Waveguide wakefield, radiation, acceleration, plasma 2772
 
  • T.Yu. Alekhina, A.V. Tyukhtin
    Saint-Petersburg State University, Saint-Petersburg, Russia
  
  Funding: Saint Petersburg State University
Analysis of a field of a particle bunch in a waveguide loaded with a dielectric is important for the wakefield acceleration technique and for other problems in accelerator physics. We investigate the field of the bunch crossing a boundary between two dielectrics in a circular waveguide. We take into account the finite length of the bunch and analyze both the field structure and the energy loss. Special attention is paid to two cases: the bunch flies from vacuum into dielectric and from dielectric into vacuum. In the first case, investigation of formation of stationary wakefield is of interest (this is important for the wakefield acceleration technique). In the second case, quasi monochromatic wave is generated in the vacuum region. This effect can be used for elaboration of a quasi-monochromatic radiation generator of new type. In both cases we also study dynamics of the energy loss of the bunch.
* T.Yu. Alekhina, A.V. Tyukhtin. Proc. of IPAC2011, San Sebastian, Spain, WEPZ012, p. 2793 (2011). 		 
 
WEPPP041 Wakefield Breakdown Test of a Diamond-loaded Accelerating Structure at the AWA wakefield, laser, simulation, electron 2813
 
  • S.P. Antipov, J.E. Butler, C.-J. Jing, A. Kanareykin, P. Schoessow, S.S. Zuo
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S. Baryshev, M.E. Conde, D.S. Doran, W. Gai, R. Konecny, J.G. Power, Z.M. Yusof
    ANL, Argonne, USA
  
  Funding: DOE SBIR
Diamond has been proposed as a dielectric material for dielectric loaded accelerating (DLA) structures. It has a very low microwave loss tangent, the highest available thermoconductive coefficient and high RF breakdown field. In this paper we report results from a wakefield breakdown test of diamond-loaded rectangular accelerating structure. The high charge beam from the AWA linac (~70 nC, σz = 2.5mm) will be passed through a rectangular diamond - loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.5 GV/m will be present on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond is be performed before and after the beam test. 		 
 
WEPPP045 Beam-breakup Analysis for an Annular Cherenkov High Gradient Wakefield Accelerator wakefield, simulation, electron, collider 2822
 
  • A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • A. Altmark
    LETI, Saint-Petersburg, Russia
  
  Funding: This work is supported by the SBIR Program of the US Department of Energy.
A complete analytical solution for Cherenkov wakefields generated by an azimuthally asymmetric annular beam propagating in a coaxial two-channel dielectric structure is presented. The transformer ratio of the annular beam Cherenkov wakefield accelerator initially proposed by R. Keinigs, M. Jones* is dramatically increased in comparison to a collinear cylindrical wakefield accelerating structure. A particle-Green's function beam dynamics code BBU-3000** to study beam breakup effects has been upgraded to incorporate annular drive beams and coaxial dielectric wakefield accelerating structures*. Beam dynamics simulations of the annular drive beam with asymmetric charge distributions have been carried out to determine the sensitivity of this method to beam imperfections in GHz and THz frequency ranges.
*R. Keinigs, M. Jones, Proc. 7th Int. Conf. High-Power Part. Beams, Beams’88, Karlsruhe, Germany, 864 (1988).
**P. Schoessow et al., AIP Conference Proceedings 1299, 262 (2010). 		 
 
WEPPR010 Comparison between Electron Cloud Build-Up Measurements and Simulations at the CERN PS electron, simulation, pick-up, extraction 2955
 
  • G. Iadarola
    Naples University Federico II, Science and Technology Pole, Napoli, Italy
  • F. Caspers, S.S. Gilardoni, G. Iadarola, E. Mahner, G. Rumolo, C. Yin Vallgren
    CERN, Geneva, Switzerland
  
  The build up of an Electron Cloud (EC) has been observed at the CERN Proton Synchrotron (PS) during the last stages of the LHC high intensity beam preparation, especially after the bunch shortening before extraction. A dedicated EC experiment, equipped with two button pick-ups, a pressure gauge, a clearing electrode, and a small dipole magnet, is available in one of the straight sections of the machine. A measurement campaign has been carried out in order to scan the EC build-up of LHC-type beams with different bunch spacing, bunch intensity, and bunch length. Such information, combined with the results from build up simulations, is of relevance for the characterization in terms of Secondary Emission Yield (SEY) of the chamber inner surface. The interest is twofold: this will enable us to predict the EC build up distribution in the PS for higher intensity beams in the frame of the upgrade program, and it will provide validation of the EC simulation models and codes.  
 
WEPPR017 Wake Fields Effects for the eRHIC Project cavity, wakefield, electron, beam-transport 2976
 
  • A.V. Fedotov, S.A. Belomestnykh, D. Kayran, V. Litvinenko, V. Ptitsyn
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An Energy Recovery Linac (ERL) with a high peak electron bunch current is proposed for the Electron-Ion collider (eRHIC) project at the Brookhaven National Laboratory. The present design is based on the multi-pass electron beam transport in existing tunnel of the Relativistic Heavy Ion Collider (RHIC). As a result of a high peak current and a very long beam transport, consideration of various collective beam dynamics effects becomes important. Here we summarize effects of the coherent synchrotron radiation, resistive wall, accelerating cavities and wall roughness on the resulting energy spread and energy loss for several scenarios of the eRHIC project, including results for different electron distributions. A possible correction scheme of accumulated correlated energy spread is also presented. 		 
 
WEPPR018 Beam Experiments towards High-intensity Beams in RHIC proton, injection, cryogenics, radiation 2979
 
  • C. Montag, L. A. Ahrens, M. Blaskiewicz, J.M. Brennan, K.A. Drees, W. Fischer, T. Hayes, H. Huang, K. Mernick, G. Robert-Demolaize, K.S. Smith, R. Than, P. Thieberger, K. Yip, K. Zeno, S.Y. Zhang
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Proton bunch intensities in RHIC will be increased from 2*1011 to 3*1011 protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results will be presented. 		 
 
WEPPR024 Motion of Charged Particle Dense Bunch in Nonuniform External Fields emittance, resonance, focusing 2985
 
  • H.Y. Barminova
    ITEP, Moscow, Russia
  • A.S. Chikhachev
    Allrussian Electrotechnical Institute, Moskow, Russia
  
  At the output of a linear resonance accelerator, a charged particle beam consists of a bunch series, with the relation between bunch length and transverse bunch size changing widely. It is of importance to describe bunch dynamics in a selfconsistent manner*,** . Usually the charged bunch is described as ellipsoid with uniform density. Such description allows easy consideration of its own bunch fields. In the case of a nonstationary distribution it is difficult to build distribution function describing 3D-ellipsoid with uniform density** . In this paper such function is found for bunch formed as rotation ellipsoid. Radii ellipsoid equations are obtained for a bunch moving in nonuniform stationary external fields.
* A.S. Chikhachev. Kinetic theory of quasystationary state of charged particle beams. Moscow,2001.
** I.M. Kapchinsky. Theory of linear resonanse accelerators. Particle dynamics. Moscow,1982. 		 
 
WEPPR032 Simulation Studies of Adiabatic Thermal Beams in a Periodic Solenoidal Focusing Field simulation, focusing, emittance, plasma 3003
 
  • C. Chen, T.J. Barton, D.M. Field, K.M. Lang
    MIT, Cambridge, Massachusetts, USA
  
  Funding: Research supported by DOE Grant No. DE-FG02-95ER40919, Grant No. DE-FG02-05ER54836, and MIT Undergraduate Research Opportunity Program.
Self-consistent simulations are performed to verify the theoretical predictions of adiabatic thermal beams in periodic solenoidal magnetic focusing fields*,**. In particular, results are obtained for adiabatic thermal beams that do not rotate in the Larmor frame. For such beams, the theoretical predictions of the rms beam envelope, the conservation of the rms thermal emittance, the adiabatic equation of state, and the Debye length are verified in the self-consistent simulations.
*K.R. Samokhvalova, J. Zhou and C. Chen, Phys. Plasma 14, 103102 (2007).
**J. Zhou, K.R. Samokhvalova and C. Chen, Phys. Plasma 15, 023102 (2008). 		 
 
WEPPR035 Optimization of Drive-bunch Current Profile for Enhanced Transformer Ratio in Beam-driven Acceleration Techniques acceleration, electron, simulation, plasma 3012
 
  • F. Lemery, D. Mihalcea, P. Piot, C.R. Prokop
    Northern Illinois University, DeKalb, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
In recent years, wakefield acceleration has gained attention due to its high acceleration gradients and cost effectiveness. In beam-driven wakefield acceleration, a critical parameter to optimize is the transformer ratio. It has been shown that current shaping of electron beams allows for enhanced (>2) transformer ratios. In this paper we present the optimization of the pulse shape of the drive bunch for dielectric-wakefield acceleration. We also explore practical techniques capable of tailoring current profiles into these optimal shapes. 		 
 
WEPPR046 THz Bursting Thresholds Measured at the Metrology Light Source storage-ring, electron, synchrotron, octupole 3030
 
  • M. Ries, J. Feikes, P.O. Schmid, G. Wüstefeld
    HZB, Berlin, Germany
  • A. Hoehl
    PTB, Berlin, Germany
  
  At the Metrology Light Source (MLS) * of the Physikalisch-Technische Bundesanstalt (PTB) the bunch length can be varied by more than two orders of magnitude **. The bunch length manipulation is achieved by varying different machine parameters, such as rf-voltage amplitude up to 500 kV and the momentum compaction factor over three orders of magnitude. The subject of this article is the measurement of THz bursting thresholds at the MLS for different bunch lengths.
* B. Beckhoff et al., Phys. Status Solidi B 246, p. 1415 (2009)
** J. Feikes et al., Phys. Rev. ST Accel. Beams 14, 030705 (2011). 		 
 
WEPPR056 Reproduction of Ceramic Chamber Impedances with Electric and Magnetic Polarities of the Ceramics impedance, dipole, synchrotron, proton 3051
 
  • Y. Shobuda, M. Kinsho
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  In proton synchrotron, ceramic chambers are used as vacuum chambers to avoid the effect on magnetic fields from eddy current excited by the magnetic fields. One of the standard methods of the derivation of the impedances of the ceramic chamber is the field matching technique. In this report, we reproduce the formulae of the ceramic chamber impedance in terms of electric and magnetic polarities. When the beam passes through the chamber, the impedance is mainly excited by the electric polarity of the ceramic.  
 
WEPPR065 Electromagnetic Simulations of the Impedance of the LHC Injection Protection Collimator simulation, impedance, injection, wakefield 3075
 
  • B. Salvant, V. Baglin, B. Goddard, A. Grudiev, E. Métral, M.A. Timmins
    CERN, Geneva, Switzerland
  
  During the 2011 LHC run, significant vacuum and temperature increase were observed at the location of the LHC injection protection collimators (TDI) during the physics fills. Besides, measurements of the LHC transverse tune shift while changing the TDI gap showed that the impedance of the TDI was significantly higher than the LHC impedance model prediction based on multilayer infinite length theory. This contribution details the electromagnetic simulations performed with a full 3D model of the TDI to obtain both longitudinal and transverse impedances and their comparison with measured observables.  
 
WEPPR070 Beam Coupling Impedance Simulations of the LHC TCTP Collimators impedance, simulation, cavity, coupling 3090
 
  • H.A. Day, R.M. Jones
    UMAN, Manchester, United Kingdom
  • F. Caspers, A. Dallocchio, L. Gentini, A. Grudiev, E. Métral, B. Salvant
    CERN, Geneva, Switzerland
  
  As part of an upgrade to the LHC collimation system, 8 TCTP and 1 TCSG collimators are proposed to replace existing collimators in the collimation system. In an effort to review all equipment placed in the accelerator complex for potential side effects due to collective effects and beam-equipment interactions, beam coupling impedance simulations are carried out in both the time-domain and frequency-domain of the full TCTP design. Particular attention is paid to trapped modes that may induce beam instabilities and beam-induced heating due to cavity modes of the device.  
 
WEPPR074 Effect of the TEM Mode on the Kicker Impedance impedance, kicker, coupling, simulation 3102
 
  • C. Zannini, G. Rumolo, V.G. Vaccaro
    CERN, Geneva, Switzerland
  • C. Zannini
    EPFL, Lausanne, Switzerland
  
  The kickers are major contributors to the CERN SPS beam coupling impedance. As such, they may represent a limitation to increasing the SPS bunch current in the frame of a luminosity upgrade of the LHC. The C-Magnet supports a transverse electromagnetic (TEM) mode due to the presence of two conductors. Due to the finite length of the structure this TEM mode affects the impedance below a certain frequency (when the penetration depth in the ferrite becomes comparable to the magnetic circuit length). A theoretical model was developed to take into account also the impedance contribution due to the TEM mode. The model is found to be in good agreement with CST 3D electromagnetic (EM) simulations. It allows for generic terminations in the longitudinal direction. An example of kicker is analyzed taking into account also the external cables.  
 
WEPPR075 Monitoring the Progress of LHC Electron-Cloud Scrubbing by Benchmarking Simulations and Pressure-Rise Observations electron, simulation, injection, dipole 3105
 
  • C.O. Domínguez, G. Arduini, E. Métral, G. Rumolo, F. Zimmermann
    CERN, Geneva, Switzerland
  • G. Iadarola
    Naples University Federico II, Science and Technology Pole, Napoli, Italy
  
  Electron bombardment of a surface has been proven to reduce drastically the secondary electron yield of a material. This technique, known as scrubbing, is the ultimate solution to decrease the negative effects of an electron cloud build-up in any particle accelerator operating with intense beams. Its effectiveness has been already observed at the LHC. Since at the LHC no in-situ secondary-yield measurements are available, it has been necessary to develop a method to infer different key beam-pipe surface parameters by benchmarking simulations and pressure-rise observations. The method developed allows us to monitor the scrubbing process in order to decide on the most appropriate strategies for machine operation. In this paper we present the latest results of applying this method to the LHC in the fall of 2011 and early 2012, including data for the nominal bunch spacing of 25 ns.  
 
WEPPR083 New Sector 37 Chamber Design and Installation for High-Current Operation of the APS Storage Ring impedance, cavity, storage-ring, HOM 3123
 
  • Y.-C. Chae, R. Bechtold, W. Berg, L. Erwin, M. Givens, J.E. Hoyt, L.H. Morrison, K.M. Schroeder, R. Soliday, J.B. Stevens, G.J. Waldschmidt
    ANL, Argonne, USA
  
  Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
The Advanced Photon Source is a 7-GeV hard x-ray synchrotron light source consisting of 40 sectors. Sector 37 accommodates four radio-frequency cavities followed by a short straight section, which is set aside for the future installation of a diagnostic device. The 60-cm-long section of spool pieces can be isolated by two gate valves and has an independent vacuum pump. The spool pieces are normally under high vacuum condition when the total current is below 100 mA. However, at the higher current required for the APS Upgrade, rf heating causes an unacceptable rise in temperature. We analyzed this situation by wakefield simulation, which led to a new chamber design. Proper fabrication and careful installation with twelve thermocouples ensured a temperature rise under 40-50 degrees Celsius at 100 mA. A brief thermal analysis shows that the present observed temperature rise in the new chamber is mainly due to the resistive wall. 		 
 
WEPPR086 Computed Wake Field Effects from Measured Surface Roughness in the Walls of the Cornell ERL wakefield, scattering, undulator, impedance 3132
 
  • M.G. Billing, G.H. Hoffstaetter, C.E. Mayes, K.W. Smolenski, H.A. Williams
    CLASSE, Ithaca, New York, USA
  
  Funding: Work supported by the NSF ERL Phase 1B Cooperative Agreement (DMR-0807731)
Wake fields arise from the discontinuities in a smooth vacuum chamber and will cause energy spread in the passing bunch. In an energy recovery linac (ERL), the spent bunches are decelerated before they are dumped to reuse the beam’s energy for the acceleration of new bunches. While the energy spread accumulated from wakes before deceleration is small compared to the beam’s energy after full acceleration, it becomes more important relatively as the beam’s energy decreases.* Thus, in an ERL wake fields can produce very significant energy spread in the beam as it is decelerated to the energy of the beam dump. We report on calculations of wake fields due to the roughness of the surface of the vacuum chamber walls as it affects the Cornell ERL design. These calculations include the effects from the measured roughness for real vacuum chamber wall surfaces.
* M. Billing, “Effect of Wake Fields in an Energy Recovery Linac”, PAC’09, Vancouver, BC, Canada, 4-8 May 2009. 		 
 
WEPPR088 Modeling and Simulation of Retarding Field Analyzers at CESRTA electron, dipole, simulation, gun 3138
 
  • J.R. Calvey, J.A. Crittenden, G. Dugan, W. Hartung, J. Makita, M.A. Palmer
    CLASSE, Ithaca, New York, USA
  • M.A. Furman, M. Venturini
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the US National Science Foundation (PHY-0734867 and PHY-1002467), and Department of Energy (DE-FC02-08ER41538).
Over the course of the CESRTA program at Cornell, Retarding Field Analyzers (RFAs) have been installed in drift, dipole, quadrupole, and wiggler field regions of the CESR storage ring. RFAs are used to measure the local electron cloud flux on the vacuum chamber wall. Through the use of a retarding grid and segmented collectors, they also provide information on the energy and transverse distribution of the cloud. Understanding these measurements on a quantitative level requires the use of cloud buildup simulation codes, adapted to include a detailed model of the structure of the RFA and its interaction with the cloud. The nature of this interaction depends strongly on the strength of the local magnetic field. We have developed models for RFAs in drift and dipole regions. The drift model has been cross-checked with bench measurements, and we have compared the RFA-adapted cloud buildup simulations with data. These comparisons have then been used to obtain best fit values for the photo-emission and secondary electron emission characteristics of some of the vacuum chamber materials and cloud mitigating coatings employed at CESRTA. 		 
 
WEPPR092 Beam Ion Instability in ILC Damping Ring with Multi-gas Species ion, damping, simulation, lattice 3150
 
  • L. Wang, M.T.F. Pivi
    SLAC, Menlo Park, California, USA
  
  Ion induced beam instability is one critical issue for the electron damping ring of the International Linear Collider (ILC) due to its ultra small emittance of 2 pm. The beam ion instability with various beam filling patterns for the latest lattice DTC02 is studied using code IONCLOUD. The code has been benchmarked with SPEAR3 experimental data and there is a good agreement between the simulation and observations. It uses the optics from MAD and can handle arbitrary beam filling pattern and vacuum. Different from previous studies, multi-gas species have been used simultaneously in the simulation. This feature makes it more accurate.  
 
WEPPR098 Two Dimensional Impedance Analysis of Segmented IVU impedance, undulator, simulation, storage-ring 3168
 
  • A. Blednykh, G. Bassi, J. Bengtsson, O.V. Chubar, C.A. Kitegi, T. Tanabe
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by DOE contract No: DE-AC02-98CH10886
Segmented Adaptive-Gap In-Vacuum Undulator (IVU) with variable magnetic gap along z-axis is considered as an alternative to the Constant Gap IVU (7mm gap) for the NSLS-II storage ring. The length of the Constant Gap IVU for a given minimum gap is limited by the beam stay clear aperture. With the new conceptual design of IVU the magnetic gap can be varied along z-axis and its minimum gap can be reduced down to 5.25mm in the center of the structure for the same stay clear aperture. Beam impedance becomes an important issue since the new design consists of several magnet gaps. Wakepotentials and impedances have been analyzed for a new type of IVU and the results compared with data for the reference geometry which is the Constant Gap IVU. 		 
 
THAP01 Secondary-electron Emission from Hydrogen-terminated Diamond electron, high-voltage, linac, simulation 3223
 
  • E. Wang, I. Ben-Zvi, T. Rao, Q. Wu
    BNL, Upton, Long Island, New York, USA
  • D.A. Dimitrov
    Tech-X, Boulder, Colorado, USA
  • T. Xin
    Stony Brook University, Stony Brook, USA
  
  Diamond amplifiers demonstrably are an electron source with the potential to support high-brightness, high-average-current emission into a vacuum. We recently developed a reliable hydrogenation procedure for the diamond amplifier. The systematic study of hydrogenation resulted in the reproducible fabrication of high gain diamond amplifier. Furthermore, we measured the emission probability of diamond amplifier as a function of the external field and modeled the process with resulting changes in the vacuum level due to the Schottky effect. We demonstrated that the decrease in the secondary electrons’ average emission gain was a function of the pulse width and related this to the trapping of electrons by the effective NEA surface. The findings from the model agree well with our experimental measurements. As an application of the model, the energy spread of secondary electrons inside the diamond was estimated from the measured emission.  
slides icon Slides THAP01 [2.034 MB]  
 
THEPPB001 Design and Fabrication of The ESS-Bilbao RFQ Prototype Models rfq, laser, alignment, simulation 3228
 
  • I. Bustinduy, F.J. Bermejo, J. Feuchtwanger, N. Garmendia, A. Ghiglino, O. González, P.J. González, I. Madariaga, J.L. Muñoz, I. Rueda, F. Sordo Balbin, A. Vélez, D. de Cos
    ESS Bilbao, Bilbao, Spain
  • V. Etxebarria, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  • A. Garbayo
    AVS, Eibar, Gipuzkoa, Spain
  • S. Jolly
    UCL, London, United Kingdom
  • S.R. Lawrie, A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  As part of the development of the ESS-Bilbao Accelerator in Spain, two different sets of radio frequency quadrupole (RFQ) models have been developed. On one hand, a set of four oxygen free high conductivity copper weld test models has been designed and manufactured, in order to test different welding methods as well as other mechanical aspects involved in the fabrication of the RFQ. On the other hand, a 352.2 MHz four vane RFQ cold model, with a length of 1 meter, has been designed and built in Aluminum. It serves as a good test bench to investigate the validity of different finite element analysis (FEA) software packages. This is a critical part, since the design of the final RFQ will be based on such simulations. The cold model also includes 16 slug tuners and 8 couplers/pick-up ports, which will allow to use the bead-pull perturbation method, by measuring the electric field profile, Q-value and resonant modes. In order to investigate fabrication tolerances, the cold model also comprises a longitudinal test modulation in the vanes, which is similar to the one designed for the final RFQ.  
 
THEPPB004 Development of a Cryocatcher-System for SIS100 ion, heavy-ion, simulation, cryogenics 3237
 
  • L.H.J. Bozyk, H. Kollmus, P.J. Spiller
    GSI, Darmstadt, Germany
  
  Funding: Work supported by EU (FP7 workpackage COLMAT) and GP-HIR – Graduate Program for Hadron and Ion Research at GSI.
The main accelerator SIS100 of the FAIR-facility will provide heavy ion beams of highest intensities using intermediate charge state heavy ions. Ionization beam loss is the most important loss mechanism, therefore, a special synchrotron layout has been developed, which includes a dedicated cold ion catcher system which provides almost hundred percent catching efficiency. Dynamic vacuum effects are suppressed effectively by means of special low desorption yield surfaces. A prototype of the cryocatcher system has been developed, constructed and tested with heavy ion beam from SIS18. It is a work package of the EU-FP-7 project COLMAT. Results from these tests are presented as well as implications for the production of the 60 SIS100 cryocatchers. 		 
 
THEPPB010 Simulation of Plasma Window for Gas Target of Neutron Source plasma, neutron, target, simulation 3251
 
  • S. Huang, S. BenLiang, Y.R. Lu, K. Zhu
    PKU/IHIP, Beijing, People's Republic of China
  
  the demand of intense mono-energy fast neutron beams grow quickly as various applications of neutron are improved. Utilizing the reaction and based on small accelerators especially the modern radio-frequency quadrupole (RFQ) accelerators to get several mA of ion beam to energies in the low MeV range, or even just only connecting to a ion source with LEBT, the neutron source can be as compact as possible to get intense fast neutrons. Traditional gas target of high pressure is sealed by several thick metal foil from the vacuum environment, which will decrease and disperse the energy of the ion beams, and at the same time reduce the strength and cause the production of rays. In the other aspects, the foil window could be damaged with short service life result from the high heat flux of the ion beam injection. To prevent of these problems, a plasma window is designed to maintain a high pressure gap between the gas target (several bar) and the vacuum vessel, with no material window at all. In this article both the computational simulation and experiment results of the plasma window will be included.  
 
THPPC001 Simulation and Design of a 70 MeV Cyclotron RF System cyclotron, simulation, cavity, resonance 3269
 
  • G. Gold, R.R. Johnson, B.F. Milton, V. Sabaiduc
    BCSI, Vancouver, BC, Canada
  
  The electromagnetic and mechanical design of the resonant cavity for a 70 MeV compact commercial cyclotron has been conducted by Best Cyclotron Systems Inc. Various resonator configurations have been studied for a radial, single-stem design and an optimal solution was selected with excellent electromagnetic properties and minimized construction and operational cost. Rapid model iterations during the design, using CST Microwave Studio and ANSYS, allowed for accurate tuning of geometry to precisely define the shape of the accelerating voltage profile, surface current distribution, and total power loss. The RF system of the BEST 70p cyclotron will operate at the fourth harmonic with two λ/2 separated resonant cavities shielded at the center allowing for beam modulation techniques to be applied through phase modulation of the accelerating voltage.  
 
THPPC012 Impedance Computation of Main Components in CSNS/RCS impedance, cavity, simulation, extraction 3299
 
  • Y. Li, L. Huang, Z.P. Li, Y.D. Liu, N. Wang, S. Wang
    IHEP, Beijing, People's Republic of China
  
  The rapid cycling synchrotron (RCS) of the China spallation neutron source (CSNS) is a high intensity proton accelerator. The study on the coupling impedance in the ring plays an important role in the stability of the beam. The impedance of the main vacuum components in the RCS ring, such as RF cavities, bellows, ports of vacuum pumps, collimator etc, was calculated by using numerical methods. Meantime, RF shielding of bellows, collimators and ports of vacuum pumps are considered. The impact of the busbar configuration on RF cavities and beams was estimated by impedance calculation.  
 
THPPC014 Commissioning Status of the 3 MeV RFQ for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University rfq, proton, ion, status 3305
 
  • Q.Z. Xing, Y.J. Bai, D.T. Bin, J.C. Cai, C. Cheng, L. Du, Q. Du, C. Jiang, Q. Qiang, D. Wang, X.W. Wang, Z.F. Xiong, S.Y. Yang, H.Y. Zhang, S.X. Zheng
    TUB, Beijing, People's Republic of China
  • J.H. Billen
    TechSource, Santa Fe, New Mexico, USA
  • W.Q. Guan, Y. He, J. Li
    NUCTECH, Beijing, People's Republic of China
  • X.L. Guan
    Tsinghua University, Beijing, People's Republic of China
  • J. Stovall
    CERN, Geneva, Switzerland
  • L.M. Young
    AES, Medford, NY, USA
  
  Funding: Work supported by the “985 Project” of the Ministry of Education of China.
We present, in this paper, the commissioning status of a Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. In 2012 the 3-meter-long RFQ will deliver 3 MeV protons to the downstream High Energy Beam Transport (HEBT) with the peak current of 50 mA, pulse length of 0.5 ms and beam duty factor of 2.5%. Braze of the vanes was completed in September, 2011. The final field tuning of the whole cavity was completed in October, 2011. Initial commissioning will be underway at the beginning of 2012. 		 
 
THPPC016 PLSII Linac RF Conditioning Status linac, klystron, high-voltage, storage-ring 3311
 
  • H.-S. Lee, J.Y. Huang, W.H. Hwang, H.-G. Kim, K.R. Kim, S.H. Kim, S.H. Kim, S.H. Nam, W. Namkung, S.S. Park, S.J. Park, Y.J. Park, S. Shin
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  PLS linac has been upgraded in energy from 2.5 to 3.0 GeV. A klystron supplies RF power of 80 MW four acceleration structures through a SLED. But our machine is not enough RF power to get 3 GeV beam energy. So we have changed the RF scheme in four modules as a klystron supplies RF power of 80 MW two accelerating structures through a SLED. There were several problems during the RF conditioning and beam operation. So we will describe the conditioning results and the current status in this paper.  
 
THPPC020 Accurate Measurement of Ferrite Garnets to be used for Fast-tuned Ferrite Loaded Cavities in the Range of 20-40 MHz cavity, impedance, resonance, dipole 3317
 
  • C. Vollinger, F. Caspers
    CERN, Geneva, Switzerland
  
  For the implementation of ferrite-tuned cavities with perpendicular biased ferrites in the frequency range of 20 to 40 MHz, different types of ferrite garnets were evaluated in terms of their electromagnetic properties. We describe a precision measurement method applicable to small-sized ferrite samples of 1-square-inch surface and 2 mm thickness in the given frequency range. During measurement, these samples are exposed to varying magnetic bias fields of different orientations. Two different techniques for the determination of the real and the imaginary part of the permeability are required to achieve sufficiently accurate results. We present a detailed description of these methods as well as results obtained.  
 
THPPC023 RF Loads for Energy Recovery cavity, synchrotron, coupling, proton 3326
 
  • S. Federmann, M. Betz, F. Caspers
    CERN, Geneva, Switzerland
  
  Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ̊C) are discussed. Another design deals with a very high temperature (up to 800 ̊C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the actual microwave absorber and is not brazed to the metallic enclosure.  
 
THPPC024 Design, Construction and Power Conditioning of the First C-band Test Accelerating Structure for SwissFEL cavity, klystron, linac, impedance 3329
 
  • R. Zennaro, J. Alex, H. Blumer, M. Bopp, A. Citterio, T. Kleeb, L. Paly, J.-Y. Raguin
    Paul Scherrer Institut, Villigen, Switzerland
  
  The SwissFEL C-band linac will consist of 26 RF modules with a total acceleration voltage of 5.4 GV. Each module will be composed of a single 50 MW klystron and its solid-state modulator feeding a pulse compressor and four two-meter long accelerating structures. PSI has launched a vigorous R&D program of development of the accelerating structures including structure design, production and high-power RF tests. The baseline design is based on ultra-precise cup machining to avoid dimple tuning. The first test structure is a constant impedance structure composed of eleven double-rounded cups. We report here on the structure design, production, low-level RF measurements, high-power conditioning and breakdown analysis.  
 
THPPC027 Measurement of the Dynamic Response of the CERN DC Spark System and Preliminary Estimates of the Breakdown Turn-on Time simulation, impedance, cathode, radio-frequency 3338
 
  • N.C. Shipman, R.M. Jones
    UMAN, Manchester, United Kingdom
  • S. Calatroni, W. Wuensch
    CERN, Geneva, Switzerland
  
  The new High Rep Rate (HRR) CERN DC Spark System has been used to investigate the current and voltage time structure of a breakdown. Simulations indicate that vacuum breakdowns develop on ns timescales or even less. An experimental benchmark for this timescale is critical for comparison to simulations. The fast rise time of breakdown may provide some explanation of the particularly high gradients achieved by low group velocity, and narrow bandwidth, accelerating structures such as the T18 and T24. Voltage and current measurements made with the previous system indicated that the transient responses measured were dominated by the inherent capacitances and inductances of the DC spark system itself. The bandwidth limitations of the HRR system are far less severe allowing rise times of around 12ns to be measured.  
 
THPPC028 Kinetic Modeling of RF Breakdown in High-Pressure Gas-filled Cavities simulation, plasma, electron, cavity 3341
 
  • D. Rose, C.H. Thoma
    Voss Scientific, Albuquerque, New Mexico, USA
  • J.M. Byrd, D. Li
    LBNL, Berkeley, California, USA
  • R.P. Johnson, M.L. Neubauer, R. Sah
    Muons, Inc, Batavia, USA
  • A.V. Tollestrup, K. Yonehara
    Fermilab, Batavia, USA
  
  Funding: Supported in part by USDOE STTR Grant DE-FG02-08ER86352
Recent studies have shown that high gradients can be achieved quickly in high-pressure gas-filled cavities without the need for long conditioning times, because the dense gas can dramatically reduce dark currents and multipacting. In this project we use this high pressure technique to suppress effects of residual vacuum and geometry found in evacuated cavities to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of radiofrequency and surface preparation. A series of experiments at 805 MHz using hydrogen fill pressures up to 0.01 g/cm3 of H2 have demonstrated high electric field gradients and scaling with the DC Paschen law limit, up to ~30 MV/m, depending on the choice of electrode material. For higher field stresses, the breakdown characteristics deviate from the Paschen law scaling. Fully-kinetic 0D collisional particle-in-cell (PIC) simulations give breakdown characteristics in H2 and H2/SF6 mixtures in good agreement with the 805 MHz experimental results below this field stress threshold. The impact of these results on gas-filled RF accelerating cavity design will be discussed. 		 
 
THPPC029 High-power Waveguide Dampers for the Short-Pulse X-Ray Project at the Advanced Photon Source HOM, cavity, damping, cryomodule 3344
 
  • G.J. Waldschmidt, B. Brajuskovic, J. Liu, M.E. Middendorf, A. Nassiri, T.L. Smith, G. Wu
    ANL, Argonne, USA
  • J. Henry, J.D. Mammosser, R.A. Rimmer, M. Wiseman
    JLAB, Newport News, Virginia, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
High-power waveguide dampers have been designed and prototyped for the Short-Pulse X-ray (SPX) cavities at the Advanced Photon Source. The cavities will operate at 2.815 GHz and utilize the TM110 dipole mode. As a result, higher-order (HOM) and lower-order mode (LOM) in-vacuum dampers have been designed to satisfy the demanding broadband damping requirements in the APS storage ring. The SPX single-cell cavity consists of two WR284 waveguides for damping the HOMs and one WR284 waveguide for primarily damping the LOM where up to 2kW will be dissipated in the damping material. The damper designs and high-power experimental results will be discussed in this paper. 		 
 
THPPC032 Conditioning and Future Plans for a Multi-purpose 805 MHz Pillbox Cavity for Muon Acceleration cavity, acceleration, solenoid, linac 3353
 
  • G.M. Kazakevich, A. Dudas, G. Flanagan, R.P. Johnson, F. Marhauser, M.L. Neubauer, R. Sah
    Muons, Inc, Batavia, USA
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
  • A. Moretti, M. Popovic, G.V. Romanov, K. Yonehara
    Fermilab, Batavia, USA
  • Y. Torun
    IIT, Chicago, Illinois, USA
  
  Funding: Supported in part by grant 4735 · 10 LANL and Dept. of Energy STTR grant DE-FG02-08ER86352.
An 805 MHz RF pillbox cavity has been designed and constructed to investigate potential muon beam acceleration and cooling techniques for a Muon Collider or Neutrino Factory. The cavity can operate in vacuum or under pressure to 100 atmospheres, at room temperature or in a liquid nitrogen bath at 77 K. The cavity has been designed for easy assembly and disassembly with bolted construction using aluminum seals. To perform vacuum and high pressure breakdown studies of materials and geometries most suitable for the collider or factory, the surfaces of the end walls of the cavity can be replaced with different materials such as copper, aluminum, beryllium, or molybdenum, and with different geometries such as shaped windows or grid structures. The cavity has been designed to fit inside the 5-Tesla solenoid in the MuCool Test Area at Fermilab. In this paper we present the vacuum conditioning results and discuss plans for testing in a 5-Tesla magnetic field. Additionally, we discuss the testing plan for beryllium (a material research has shown to be ideal for the collider or factory) end walls. 		 
 
THPPC033 Progress on a Cavity with Beryllium Walls for Muon Ionization Cooling Channel R&D cavity, coupling, electron, simulation 3356
 
  • D.L. Bowring, A.J. DeMello, A.R. Lambert, D. Li, S.P. Virostek, M.S. Zisman
    LBNL, Berkeley, California, USA
  • D.M. Kaplan
    Illinois Institute of Technology, Chicago, Illinois, USA
  • R.B. Palmer
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Muon Accelerator Program (MAP) collaboration is working to develop an ionization cooling channel for future muon colliders. The ionization cooling channel requires the operation of high-gradient, normal-conducting RF cavities in solenoidal magnetic fields up to 5 T. However, experiments conducted at Fermilab's MuCool Test Area (MTA) show that increasing the solenoidal field strength reduces the maximum achievable cavity gradient. This gradient limit is characterized by an RF breakdown process that has caused significant damage to copper cavity interiors. The damage is likely caused by field-emitted electrons, focused by the solenoidal magnetic field onto small areas of the inner cavity surface. Local heating may then induce material fatigue and surface damage. Fabricating a cavity with beryllium walls would mitigate this damage due to beryllium's low density, low thermal expansion, and high electrical and thermal conductivity. This poster addresses the design and fabrication of a pillbox RF cavity with beryllium walls, in order to evaluate the performance of high-gradient cavities in strong magnetic fields. 		 
 
THPPC034 Design and Analysis of the PXIE CW Radio-frequency Quadrupole (RFQ) rfq, cavity, controls, quadrupole 3359
 
  • S.P. Virostek, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples
    LBNL, Berkeley, California, USA
  • G.V. Romanov
    Fermilab, Batavia, USA
  • C. Zhang
    IAP, Frankfurt am Main, Germany
  
  Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Project X Injector Experiment (PXIE) will be a prototype front end of the Project X accelerator proposed by Fermilab. PXIE will consist of an H− ion source, a low-energy beam transport (LEBT), a radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a section of superconducting cryomodules that will accelerate the beam from 30 keV to 30 MeV. LBNL has developed an RFQ design for PXIE with fabrication scheduled to begin before the end of CY 2012. The chosen baseline design is a four-vane, 4.4 m long CW RFQ with a resonant frequency at 162.5 MHz (2.4 wavelengths long). The RFQ will provide bunching and acceleration of a nominal 5 mA H− beam to 2.1 MeV. The relatively low wall power density results in wall power losses that are less than 100 kW. The beam dynamics design has been optimized to allow for more than 99% beam capture with exceptionally low longitudinal emittance. The RFQ mechanical design and the results of RF and thermal analyses are presented here. 		 
 
THPPC035 Final Assembly and Testing of the MICE Superconducting Spectrometer Solenoids solenoid, radiation, instrumentation, focusing 3362
 
  • S.P. Virostek, M.A. Green, T.O. Niinikoski, H. Pan, S. Prestemon
    LBNL, Berkeley, California, USA
  • R. Preece
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  
  Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231.
The Muon Ionization Cooling Experiment (MICE) is an international effort to demonstrate the principle of ionization cooling in a segment of a realistic cooling channel using a muon beam. The experiment is sited at Rutherford Appleton Laboratory in England. A 4-tesla uniform field region at each end of the cooling channel will be provided by a pair of identical, 3-m long spectrometer solenoids. As the beam enters and exits the cooling channel, the emittance will be measured within both the upstream and downstream 400 mm diameter magnet bores. Each magnet consists of a three-coil spectrometer magnet group and a two-coil pair that matches the solenoid uniform field into the adjacent MICE cooling channel. An array of five two-stage cryocoolers and one single-stage cryocooler are used to maintain the temperature of the magnet cold mass, radiation shield and current leads. Previous testing revealed several operational and design issues related to heat leak and quench protection that have since been corrected. Details of the magnet design modifications and their final assembly as well as the results of quench training tests will be presented here. 		 
 
THPPC043 Cold Test of an L-band, 2-Cell PWT Photoelectron cavity, gun, simulation, electron 3380
 
  • Y. Luo, D. Yu
    DULY Research Inc., Rancho Palos Verdes, California, USA
  • R. Andrews, T.N. Khabiboulline
    Fermilab, Batavia, USA
  
  Funding: DOE SBIR Grant No. DE-FG02-06ER84460
An L-band, 1+2/2-cell PWT gun with a coax coupler has been designed for high vacuum polarized electron source applications by DULY Research Inc. A cold test model was fabricated and is currently undergoing test at Fermilab, where the gun will eventually be hot tested. The aluminum cold test model includes an rf/ vacuum sieve, 2 disks, endplates, 6 supporting rods and a 6” CF flange, clamped together during testing. Fermilab made measurements for the cavity resonant frequency and axial field distribution using bead pull. To measure the resonant frequency of the cavity small diameter probes are placed through the vacuum sieve slot. A larger diameter probe can be used as an active tuner. This paper presents the results of the cold test and compares measurements with simulation results from 3D SLAC code Omega3p. The axial field distributions are in good agreement with each other. Frequency deviation is less than 0.5%, well within the experimental accuracy. 		 
 
THPPC045 Rapidly Tunable RF Cavity for Accelerators cavity, acceleration, synchrotron, simulation 3386
 
  • D.J. Newsham, N. Barov
    Far-Tech, Inc., San Diego, California, USA
  
  Funding: Work supported by the DOE-SBIR program, High Energy Physics Department.
The performance and range efficient use of rapidly cycling accelerators would be improved with the fast frequency tuning and associated variable phase change provided by a tunable rf cavity. The progress in developing a cavity that can be tuned by as much as 10 percent in frequency in less than 100 nanoseconds is presented. 		 
 
THPPC046 Normal Conducting Radio Frequency x-band Deflecting Cavity Fabrication and Validation alignment, cavity, electron, linear-collider 3389
 
  • R.B. Agustsson, L. Faillace, A.Y. Murokh, S. Storms
    RadiaBeam, Santa Monica, USA
  • D. Alesini
    INFN/LNF, Frascati (Roma), Italy
  • V.A. Dolgashev
    SLAC, Menlo Park, California, USA
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • V. Yakimenko
    BNL, Upton, Long Island, New York, USA
  
  Funding: U.S. DOE SBIR grant DE-FG02-05ER84370
An X-band Traveling wave Deflector mode cavity (XTD) has been developed and fabricated at Radiabeam Technologies to perform longitudinal characterization of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. An XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, structure fabrication, cold testing results and commissioning plans are presented. 		 
 
THPPC047 Fabrication and Initial Tests of an Ultra-High Gradient Compact S-Band (HGS) Accelerating Structure coupling, klystron, linac, accelerating-gradient 3392
 
  • L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh
    RadiaBeam, Santa Monica, USA
  • V.A. Dolgashev
    SLAC, Menlo Park, California, USA
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • V. Yakimenko
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by US DOE grant # DE-SC000866.
RadiaBeam Technologies reports on the RF design and fabrication of a ultra-high gradient (50 MV/m) S-Band accelerating structure (HGS) operating in the pi-mode at 2.856 GHz. The compact HGS structure offers a drop-in replacement for conventional S-Band linacs in research and industrial applications such as drivers for compact light sources, medical and security systems. The electromagnetic design (optimization of the cell shape in order to maximize RF efficiency and minimize surface fields at very high accelerating gradients) has been carried out with the codes HFSS and SuperFish while the thermal analysis has been performed by using the code ANSYS. The initial cold tests are presented together with the plans for high-power tests currently ongoing at Lawrence Livermore National Laboratory (LLNL). 		 
 
THPPC048 Innovative Low-Energy Ultra-Fast Electron Diffraction (UED) System electron, cathode, gun, high-voltage 3395
 
  • L. Faillace, S. Boucher
    RadiaBeam, Santa Monica, USA
  • P. Musumeci
    UCLA, Los Angeles, California, USA
  
  Funding: Work supported by DOE.
RadiaBeam, in collaboration with UCLA, is developing an innovative, inexpensive, low-energy ultra-fast electron diffraction (UED) system which allows us to reconstruct a single ultrafast event with a single pulse of electrons. Time resolved measurement of atomic motion is one of the frontiers of modern science, and advancements in this area will greatly improve our understanding of the basic processes in materials science, chemistry and biology. The high-frequency (GHz), high voltage, phase-locked RF field in the deflector allows temporal resolution as fine as 100 fs. In this paper, we show the complete design of a UED system based on this concept, including an optimized electron gun, a high-resolution RF deflector, and the post-interaction imaging system. 		 
 
THPPC054 Installation and Tests of the X-Band Power Plant for the FERMI@Elettra Project klystron, FEL, LLRF, power-supply 3410
 
  • G. D'Auria, P. Delgiusto, F. Gelmetti, M.M. Milloch, A. Milocco, F. Pribaz, C. Serpico, N. Sodomaco, M. Svandrlik, R. Umer, L. Veljak
    ELETTRA, Basovizza, Italy
  
  FERMI@Elettra, the fourth generation light source facility at the Elettra Laboratory in Trieste, Italy, foresees an X-band accelerating section downstream the first bunch compressor to linearize the beam longitudinal phase space. The RF power for the structure is produced by the SLAC XL5 klystron, a scaled version of the XL4 tube, operating at the European frequency of 11.992 GHz. The 50 Hz klystron modulator is based on a standard pulse forming network (PFN) design, with thyratron and pulse transformer, for which there is already an extensive experience at the Elettra laboratory. We report about the installation and tests of the first high power RF station.  
 
THPPC060 Commissioning of the First Klystron-based X-band Power Source at CERN klystron, controls, high-voltage, low-level-rf 3428
 
  • J.W. Kovermann, N. Catalan-Lasheras, S. Curt, S. Döbert, G. McMonagle, S.F. Rey, G. Riddone, K.M. Schirm, I. Syratchev, L. Timeo
    CERN, Geneva, Switzerland
  • J.P. Eichner, A.A. Haase, D.W. Sprehn
    SLAC, Menlo Park, California, USA
  • A. Hamdi, F. Peauger
    CEA/DSM/IRFU, France
  
  A new klystron based x-band rf power source working at 11.994GHz has been installed and commissioned at CERN in collaboration with CEA Saclay and SLAC for CLIC accelerating structure tests. The system comprises a solid state high voltage modulator, an XL5 klystron developed by SLAC, a cavity based SLED type pulse compressor, the necessary low level rf system including rf diagnostics and interlocks and the surrounding vacuum, cooling and controls infrastructure. The klystron can produce up to 50MW rf pulses of 1500ns pulse width and 50Hz repetition rate. After pulse compression, up to 100MW of rf power at 250ns pulse with are available in the structure test bunker. This paper describes in more detail this setup and the results of the commissioning which was necessary to arrive at the mentioned performance.  
 
THPPC061 A 12 kV, 1 kHz, Pulse Generator for Breakdown Studies of Samples for CLIC RF Accelerating Structures controls, power-supply, RF-structure, radio-frequency 3431
 
  • R.H. Soares, M.J. Barnes, S. Calatroni, J.W. Kovermann, W. Wuensch
    CERN, Geneva, Switzerland
  
  Compact Linear Collider (CLIC) RF structures must be capable of sustaining high surface electric fields, in excess of 200 MV/m, with a breakdown (BD) rate below 3×10-7 breakdowns/pulse/m. Achieving such a low rate requires a detailed understanding of all the steps involved in the mechanism of breakdown. One of the fundamental studies is to investigate the statistical characteristics of the BD rate phenomenon at very low values to understand the origin of an observed dependency of the surface electric field raised to the power of 30. To acquire sufficient BD data, in a reasonable period of time, a high repetition rate pulse generator is required for an existing d.c. spark system at CERN. Following BD of the material sample the pulse generator must deliver a current pulse of several 10’s of Amperes for ~2 μs. A high repetition rate pulse generator has been designed, built and tested; this utilizes pulse forming line technology and employs MOSFET switches. This paper describes the design of the pulse generator and presents measurement results.  
 
THPPD011 Radiation Hard Magnets at the Paul Scherrer Institute radiation, target, shielding, neutron 3518
 
  • A.L. Gabard, J.P. Duppich, D. George
    Paul Scherrer Institut, Villigen, Switzerland
  
  Radiation hard magnets have been in operation at PSI for more than 30 years. Throughout this period, extensive experience was gained regarding both the conceptual design of these magnets and their operation. Worldwide, upcoming future projects for high intensity accelerators and spallation sources will create an increasing need for radiation hard magnets. Through a presentation of the PSI main accelerator facilities, this paper describes the lessons learned over the years regarding the operation of radiation hard magnets and explains a few basic design concepts adopted by PSI based on this experience.  
 
THPPD012 Measurement of Injection System of AC Septum Magnets for TPS Storage Ring septum, injection, storage-ring, shielding 3521
 
  • F.-Y. Lin, C.-H. Chang, C.-S. Fann, C.-S. Hwang, C.S. Yang
    NSRRC, Hsinchu, Taiwan
  
  Taiwan Photon Source (TPS) is a 3 GeV third generation light source and will be operated in top-up injection mode. The leakage field of the septum magnet will dominate the injection performance. The septum magnets, parts of injection system, consist of AC and DC current mode magnets. The AC septum magnet were designed and constructed by NSRRC. In order to verify the magnetic field quality and the leakage field distribution, the search coil probe and the printed circuit technology for long coil probe measurement systems are developed and implemented for magnetic field measurement. This paper will describe the magnetic field measurement system, the magnetic field mapping results and the field shielding performance of AC septum magnet.  
 
THPPD014 Design and Performance of Various kinds of Corrector Magnets for the Taiwan Photon Source feedback, booster, simulation, power-supply 3524
 
  • C.Y. Kuo, C.-H. Chang, M.-H. Huang, C.-S. Hwang, J.C. Jan, F.-Y. Lin
    NSRRC, Hsinchu, Taiwan
  
  Three types of DC corrector magnets will be installed in the booster ring (BR), LINAC to booster (LTB) and booster to storage ring (BTS) in the Taiwan photon source (TPS). These DC corrector magnets have different gap sizes, iron lengths and field strengths for different bending angles to optimize the electron beam. The DC magnetic fields are simulated by TOSCA 2D/3D static field analysis and optimum processes are discussed. An AC steering fast feedback corrector (FFC) combines horizontal and vertical dipole fields for the fast feedback correction in the storage ring (SR). The field variation with the alternating current in the 300Hz frequency of the FFC magnet is simulated by the Opera 3d ELEKTRA/SS analysis module to estimate the operating current. This paper will be presented about features, design concept and results of field measurement of these corrector magnets.
NSRRC, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan 		 
 
THPPD032 Consolidation of the LHC Superconducting Circuits: A Major Step towards 14 TeV Collisions dipole, superconducting-magnet, quadrupole, controls 3575
 
  • J.Ph. G. L. Tock, F.F. Bertinelli, F. Bordry, P. Fessia, R. Ostojic, A. Perin, H. Prin, F. Savary, C.E. Scheuerlein, H.H.J. Ten Kate, A.P. Verweij, G.P. Willering
    CERN, Geneva, Switzerland
  
  Following the incident in one of the main dipole circuits of the Large Hadron Collider (LHC) in September 2008, a detailed analysis of all magnet circuits has been performed by a dedicated task force. This analysis has revealed several critical issues in the design of the 13 kA splices between the main LHC cryomagnets. These splices have to be consolidated before increasing the beam energy above 4 TeV and to operate the LHC close to 7 TeV per beam. The design for the consolidated 13 kA splices is now complete and has been reviewed by an international committee of experts. In the process, all types of superconducting circuits have been thoroughly screened and several important recommendations were established. They were critically assessed and the resulting actions are presented. In addition to the work on the 13 kA splices, other interventions will be performed during the first long shut-down of the LHC to consolidate globally all the superconducting circuits. The associated quality controls have been defined and are detailed in the operations workflow. The schedule constraints, repairs production rate, available space and resources are presented as well.  
 
THPPD045 High Temperature Superconducting Magnets for Efficient Low Energy Beam Transport Systems solenoid, ion, rfq, emittance 3614
 
  • J.H. Nipper, G. Flanagan, R.P. Johnson
    Muons, Inc, Batavia, USA
  • M. Popovic
    Fermilab, Batavia, USA
  
  Modern ion accelerators and ion implantation systems need very short, highly versatile, Low Energy Beam Transport (LEBT) systems. The need for reliable and continuous operation requires LEBT designs to be simple and robust. The energy efficiency of available high temperature superconductors (HTS), with efficient and simple cryocooler refrigeration, is an additional attraction. Innovative, compact LEBT systems based on solenoids designed and built with high-temperature superconductor will be developed using computer models and prototyped. The parameters will be chosen to make this type of LEBT useful in a variety of ion accelerators, ion implantation systems, cancer therapy synchrotrons, and research accelerators, including the ORNL SNS. The benefits of solenoids made with HTS will be evaluated with analytical and numerical calculations for a two-solenoid configuration, as will be used in the SNS prototype LEBT that will replace the electrostatic one at SNS, and a single solenoid configuration, as was proposed for the Fermilab proton driver that will be most applicable to ion implantation applications.  
 
THPPD058 Reduction of Conductive EMI Noise Resulted from the Commercial Power Supply power-supply, high-voltage, impedance, coupling 3644
 
  • C.S. Chen, C.K. Chan, J.-C. Chang, Y.L. Chu, K.H. Hsu, C.Y. Kuo, Y.-H. Liu, C.S. Yang
    NSRRC, Hsinchu, Taiwan
  
  Almost every electronic equipment must be connected to power system. Because of the complexity of power lines, the reduction of conductive electro-magnetic interference (C-EMI) plays an important role in precise measurements. In this paper, a line impedance stabilization network (LISN) was built up to get the spectrum from power lines. After several measurements by some commercial power supplies, it is found that some of these power supplies induce effectively C-EMI into power lines, even if a passive filter is bound in power line. These noises may influence numerous equipments in a local area near the sources. Therefore, how to choose a suitable filter is a decisive factor to reduce the magnitude of C-EMI.  
 
THPPD070 Design of High Power Pulse Modulator for Driving of Twystron used in S-band Linear Accelerator electron, klystron, power-supply, cathode 3674
 
  • V. Aslani, F. AbbasiDavani, F. Ghasemi, M.Sh. Shafiee
    sbu, Tehran, Iran
  
  This design related to an s-band linear accelerator that the main tube and buncher of it have been made. RF power supply is used in this accelerator tube made up of a Twystron with 2.5 MW peak power and frequency band width 2.9~3.1 GHz. This paper offers the design of modulator for this RF amplifier. This modulator design uses solid-state method and is under construction with specification of ; Adjustable voltage from 0 to 120 kV, adjustable pulse width 2 until7μsecond, adjustable repetition rate 80-120 Hz ,ripple less than0.25% and efficiency up 80 percent. This system designed with series of 6 modules that each of them provides 5kV and IGBT switches that transform the voltage on the pulse transformer.  
 
THPPD074 Effect of a Metallized Chamber upon the Field Response of a Kicker Magnet: Simulation Results and Analytical Calculations kicker, simulation, ion, booster 3686
 
  • M.J. Barnes, M.G. Atanasov, T. Fowler, T. Kramer, T. Stadlbauer
    CERN, Geneva, Switzerland
  
  Metallized racetrack vacuum chambers will be used in the pulsed magnets of the Austrian cancer therapy and research facility, MedAustron. It is important that the metallization does not unduly degrade field rise and fall times or the flattop of the field pulse in the pulsed magnets. This was of particular concern for a tune kicker magnet, which has a specified rise and fall time of 100 ns. The impact of the metallization, upon the transient field response, has been determined by finite element method (FEM) simulations: the dependency of the field response to the metallization thickness and resistivity are presented. Formulae for the field response, which permit the use of a ramped transient excitation current, are presented: thus the coating thickness and resistivity can be determined which result in a maximum permissible field attenuation and delay for a given current rise time. In addition, results of simulations of the effect of a magnetic brazing collar, located between the ceramic vacuum chamber and flange, are reported.  
 
THPPP003 Coupling Impedance Study of the New Injection Kicker Magnets of the JPARC Main Ring impedance, kicker, coupling, simulation 3725
 
  • K. Fan, S. Fukuoka, H. Matsumoto, T. Sugimoto, T. Toyama
    KEK, Ibaraki, Japan
  
  New lumped inductance kicker magnets have been developed for the J-PARC main ring injection system. For high intensity beam operation, the beam coupling impedance of the new kickers is a critical issue, which not only generates significant heating inside the ferrite impairing the performance of the kickers, but also drives beam instability. Numerical simulations based on CST studio have been studied during the design stage to optimize the kicker structure. Impedance measurements based on wire method have been carried out. The measured results agree well with the simulation results.  
 
THPPP007 Proton-Beam Emittance Growth in SPS Coasts emittance, cavity, proton, simulation 3737
 
  • R. Calaga, L. Ficcadenti, E. Métral, R. Tomás, J. Tückmantel, F. Zimmermann
    CERN, Geneva, Switzerland
  
  Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
Proton-beam transverse emittance growth rates have been measured during SPS coasts to assess the possibility of using the SPS as a testbed for the LHC prototype crab cavities. The SPS measurements in coasts were performed at different beam energies, for varying RF voltage, beam intensity, and chromaticity. Results from these measurements are presented with potential explanations for the observed emittance growth. 		 
 
THPPP008 The ELENA Project: Progress in the Design extraction, electron, antiproton, emittance 3740
 
  • T. Eriksson, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, C. Carli, R. Kersevan, M. Martini, S. Maury, S. Pasinelli, G. Tranquille
    CERN, Geneva, Switzerland
  • W. Oelert
    Forschungszentrum Jülich GmbH, Institut fur Nuklearchemie (INC), Jülich, Germany
  
  The Extra Low ENergy Antiproton ring (ELENA) project started in June 2011 and is aimed at substantially increasing the number of antiprotons delivered to the Antiproton Decelerator (AD) physics community. ELENA will be a small machine that receives antiprotons from AD at 5.3 MeV kinetic energy and decelerates them further down to 100 keV. It will be equipped with an electron cooler to avoid beam losses during deceleration and to reduce beam phase space at extraction. Design work is progressing with emphasis on machine parameters and design as well as infrastructure, ring, transfer lines and vital subsystem design.  
 
THPPP015 A Clamped Be Window for the Dump of the HiRadMat Experiment at CERN synchrotron, simulation, beam-loading, cavity 3758
 
  • M. Delonca, T. Antonakakis, D. Grenier, C. Maglioni, A. Sarrió Martínez
    CERN, Geneva, Switzerland
  
  At CERN, the High Radiation to Materials facility (HiRadMat) is designed to test accelerator components under the impact of high-intensity pulsed beams and will start operation in 2012. In this frame a LHC TED -type dump was installed at the end of the line, working in nitrogen over-pressure, and a 258μm-thick beryllium window was placed as barrier between the inside of the dump and the external atmosphere. Because of the special loading conditions, a clamped window design was especially developed, optimized and implemented, the more standard welded window not being suitable for such loads. Considering then the clamping force and the applied differential pressures, the stresses on the window components were carefully evaluated thanks to empirical as well as numerical models, to guarantee the structural integrity of the beryllium foil. This paper reports on choices and optimizations that led to the final design, presenting also comparative results from different solutions and the detailed results for the adopted one.  
 
THPPP017 ELENA: From the First Ideas to the Project antiproton, electron, extraction, rfq 3764
 
  • G. Tranquille, P. Belochitskii, T. Eriksson, S. Maury
    CERN, Geneva, Switzerland
  • W. Oelert
    Forschungszentrum Jülich GmbH, Institut fur Nuklearchemie (INC), Jülich, Germany
  
  Successful commissioning of the CERN Antiproton Decelerator (AD) in 2000 was followed by significant progress in the creation of antihydrogen atoms. The extraction energy of the decelerated antiprotons is nevertheless very high compared to that required by experiments and results in a trapping efficiency of only 0.1% to 3%. To improve this value by an order of magnitude the study of an Extra Low ENergy Antiproton ring (ELENA) started in 2003 and was approved as a CERN construction project in 2011. During these years the choice of the main machine parameters such as the beam extraction energy, emittance and bunch length were defined, taking into account requests from the physics community. The main challenges were also identified, such as dealing with the large space charge tune, the ultra high vacuum required and the tight requirements for the electron cooler. Housing the ELENA ring within the AD hall significantly reduced the project cost as well as simplifying the beam transfer from AD to ELENA and from ELENA to the existing experimental areas. This contribution will follow ELENA from its beginnings to the final, approved project proposal.  
 
THPPP018 Operation of the LHC at High Luminosity and High Stored Energy luminosity, injection, emittance, radiation 3767
 
  • J. Wenninger, R. Alemany-Fernandez, G. Arduini, R.W. Assmann, B.J. Holzer, E.B. Holzer, V. Kain, M. Lamont, A. Macpherson, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli Camillocci, J.A. Uythoven, W. Venturini Delsolaro
    CERN, Geneva, Switzerland
  
  In 2011 the operation of the Large Hadron Collider LHC entered its first year of high luminosity production at a beam energy of 3.5 TeV. In the first months of 2011 the number of bunches was progressively increased to 1380, followed by a reduction of the transverse emittance, an increase of the bunch population and a reduction of the betatron function at the collision points. The performance improvements steps that were accumulated in 2011 eventually brought the peak luminosity to 3.6·1033 cm-2s−1. The integrated luminosity delivered to each of the high luminosity experiments amounted to 5.6 fb-1, a factor of 5 above the initial target defined in 2010. The operational experience with high intensity and high luminosity at the LHC will be presented here, together with the issues that had to be tackled on the road to high intensity and luminosity.  
 
THPPP053 The Manufacture and Assembly of the FETS RFQ rfq, alignment, simulation, controls 3862
 
  • P. Savage, J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • A. Garbayo
    AVS, Eibar, Gipuzkoa, Spain
  • A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • D.S. Wilsher
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  
  The Rutherford Appleton Laboratory (RAL) Front End Test Stand (FETS) uses a 324 MHz 4-vane RFQ to accelerate H− ions from 65keV to 3MeV. The RFQ is a copper structure that has been designed as 4 nominally one metre long assemblies. Each assembly consists of 2 major vanes and 2 minor vanes that are bolted together and sealed using an O ring. The mechanical design for the FETS RFQ is complete and the manufacture is underway. In order to achieve the designed physics performance the vanes must be machined and assembled to high degree of accuracy. This requirement has demanded a tight synergy between the design, manufacture and metrology services. Together they have developed detailed procedures for the manufacturing, inspection, alignment and assembly phases. The key points of these procedures will be detailed in this paper.  
 
THPPP054 A New Half-Wave Resonator Cryomodule Design for Project-X cryomodule, cavity, alignment, focusing 3865
 
  • Z.A. Conway, A.O. Bergado, R.L. Fischer, M. Kedzie, M.P. Kelly, B. Mustapha, P.N. Ostroumov
    ANL, Argonne, USA
  • V.A. Lebedev
    Fermilab, Batavia, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contract DE-AC02-76CH03000 and DE-AC02-06CH11357.
We present the current status of our Project-X half-wave resonator cryomodule development effort. The Project-X injector requires a single cryomodule with 9 superconducting, 162.5-MHz, β = 0.11, half-wave resonators interleaved with 6 integrated superconducting solenoids/steering coils. This cryomodule is being designed and build by ANL with the intent of delivering a device which has all external connections to the cryogenic, RF, and instrumentation systems located at removable junctions separated from the clean cavity vacuum system. Issues include the ease of assembly, cavity cleanliness, interfacing to subsystems (e.g., cryogenics, couplers, tuners, etc.), and satisfying the ANL/FNAL/DOE guidelines for vacuum vessels. We employ proven warm-to-cold low-particulate beamline transitions to minimize unused space along the linac, a top-loading box design that minimizes the size of the clean room assembly, and compact beamline devices to minimize the length of the focusing period. 		 
 
THPPP063 CW Room Temperature Re-buncher for the Project X Front End cavity, linac, simulation, beam-transport 3880
 
  • G.V. Romanov, M.H. Awida, M. Chen, I.V. Gonin, S. Kazakov, R.A. Kostin, V.A. Lebedev, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on a superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The front end of the linac contains a cw room-temperature MEBT section which comprises an ion source, RFQ, and high-bandwidth bunch selective chopper. The length of the MEBT exceeds 9 m, so three re-bunching cavities are used to support the beam longitudinal dynamics. The paper reports RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.  
 
THPPP065 The FNAL Injector Upgrade Status rfq, emittance, extraction, beam-transport 3886
 
  • C.-Y. Tan, D.S. Bollinger, K.L. Duel, P.R. Karns, J.R. Lackey, W. Pellico, V.E. Scarpine, R.E. Tomlin
    Fermilab, Batavia, USA
  
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The new FNAL H− injector upgrade is currently being tested before installation in the Spring 2012 shutdown of the accelerator complex. This line consists of an H− source, low energy beam transport (LEBT) and 200 MHz RFQ. Beam measurements have been performed to validate the design before installation. The results of the beam measurements are presented in this paper. 		 
 
THPPP083 Status of J-PARC 3 GeV RCS injection, extraction, beam-losses, beam-transport 3927
 
  • M. Kinsho
    JAEA/J-PARC, Tokai-mura, Japan
  
  J-PARC RCS have delivered beam progressively since 2008. The RCS ramped up the beam power, and delivered beam of 300kW equivalent and 220kW to MR and MLF, respectively, before the earthquake disaster. The RCS was heavily affected by the last Great East Japan Earthquake. At the RCS, the circulating road went wavy and the yard area for electricity and cooling water devices was heavily distorted. We have investigated damages of each device and also have tried to restore beam operation. From middle of December last year we could start beam test and also would start to deliver beam to MR and MLF for user operation from this January. We have been performed not only recovery works but also improvement of the RCS for realizing high power stable operation with low beam losses. I report status of beam operation and near future plan for the RCS.  
 
THPPP093 Progress on MICE RFCC Module cavity, coupling, solenoid, controls 3954
 
  • D. Li, D.L. Bowring, A.J. DeMello, S.A. Gourlay, M.A. Green, N. Li, T.O. Niinikoski, H. Pan, S. Prestemon, S.P. Virostek, M.S. Zisman
    LBNL, Berkeley, California, USA
  • A.D. Bross, R.H. Carcagno, V. Kashikhin, C. Sylvester
    Fermilab, Batavia, USA
  • Y. Cao, S. Sun, L. Wang, L. Yin
    SINAP, Shanghai, People's Republic of China
  • A.B. Chen, B. Guo, L. Li, F.Y. Xu
    ICST, Harbin, People's Republic of China
  • D.M. Kaplan
    Illinois Institute of Technology, Chicago, Illinois, USA
  • T.H. Luo, D.J. Summers
    UMiss, University, Mississippi, USA
  
  Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231, US Muon Accelerator Program and NSF MRI award: 0959000.
Recent progress on the design and fabrication of the RFCC (RF and Coupling Coil) module for the international MICE (Muon Ionization Cooling Experiment) will be reported. The MICE ionization cooling channel has two RFCC modules; each having four 201-MHz normal conducting RF cavities surrounded by one superconducting coupling coil (solenoid) magnet. The magnet is designed to be cooled by 3 cryocoolers. Fabrication of the RF cavities is complete; preparation for the cavity electro-polishing, low power RF measurements and tuning are in progress at LBNL. Fabrication of the cold mass of the first coupling coil magnet has been completed in China and the cold mass arrived at LBNL in late 2011. Preparations for testing the cold mass are currently under way at Fermilab. Plans for the RFCC module assembly and integration are being developed and will be described. 		 
 
THPPR011 Insertion Device Controls Plan of the Taiwan Photon Source controls, insertion, insertion-device, EPICS 3987
 
  • C.Y. Wu, J. Chen, Y.-S. Cheng, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.H. Kuo, D. Lee, C.Y. Liao
    NSRRC, Hsinchu, Taiwan
  
  Insertion device (ID) is a crucial component in third-generation synchrotron light sources, which can produces highly-brilliant, forward-directed and quasi-monochromatic radiation over a broad energy range for various experiments. In the phase I of the Taiwan Photon Source (TPS) project, ten insertion devices (IDs) will be planned, constructed, and installed for the first seven beamlines. The control system for all the IDs is based on the EPICS architecture. The main control components include the motor with encoder for gap adjustment, trim coil power supply for corrector magnets, temperature sensor for ID environmental monitoring and baking (only for In-Vacuum Undulator), and interlock system (limit switches, tilt sensor) for safety. The progress of the controls plan will be summarized in this report.  
 
THPPR025 Operational Efficiency of the AIRIX Accelerator Since its Commissioning electron, high-voltage, site, induction 4017
 
  • H. Dzitko, V. Bernigaud, A. Georges, B. Gouin, G. Grandpierre, M. Mouillet
    CEA, Pontfaverger-Moronvilliers, France
  • L. Buche, Y. Collet, S. Combacon, G. Gobert, R. Nicolas, R. Reynaud
    CEA/DAM/DIF, Arpajon, France
  
  AIRIX is a high current (19 MeV, 2 kA) electron linear induction accelerator used as a 60 ns single shot X-ray source for hydrodynamic experiments. As single shot experiments are performed, the best performances and a high reliability level must be met for each experiment. This accelerator has been running for hydroshot experiments since 2000 and several thousands electron and X-ray beams have been produced so far. The functioning time of the AIRIX machine in the CEA/Moronvilliers test site is now coming to its end. From mid-2012, it will be then refurbished, dismounted and moved to another CEA test site. This paper draws up the report of AIRIX operations over this long eleven-year period. Maintenance policy, relative cost efficiency, reliability and performance results of the AIRIX accelerator over this period are dealt with and discussed.  
 
THPPR030 High Power Test of RF Separator For 12 GeV Upgrade of CEBAF at Jefferson Lab cavity, ion, extraction, coupling 4032
 
  • S. Ahmed, C. Hovater, G.A. Krafft, J.D. Mammosser, M. Spata, M.J. Wissmann
    JLAB, Newport News, Virginia, USA
  • J.R. Delayen
    ODU, Norfolk, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate enough to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, several options including the extension of existing normal conducting (NC) and a potential 499 MHz TEM-type superconducting (SC) cavity design have been investigated using computer simulations. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test to 4 kW is required to confirm the cavity’s operate-ability at these elevated gradient and power levels. We have assembled a 2-cell cavity, pumped down to 2.0·10-9 torr using ion pump and confirmed the low level RF performance. A high power test is in progress and will be completed soon. The detailed numerical and experimental results will be discussed in the paper. 		 
 
THPPR044 A New Electron Beam Test Facility (EBTF) at Daresbury Laboratory for Industrial Accelerator System Development electron, gun, FEL, laser 4074
 
  • P.A. McIntosh, D. Angal-Kalinin, S.R. Buckley, J.A. Clarke, A.R. Goulden, C. Hill, S.P. Jamison, J.K. Jones, A. Kalinin, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, T.T. Ng, B.J.A. Shepherd, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • N. Bliss, G.P. Diakun, A. Gleeson, T.J. Jones, B.G. Martlew, A.J. Moss, L. Nicholson, M.D. Roper, C.J. White
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  Recent UK government funding has facilitated the implementation of a unique accelerator test facility which can provide enabling infrastructures targeted for the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications for medicine, health, security, energy and industrial processing. The infrastructure provision on the Daresbury Science and Innovation Campus (DSIC) will permit research into areas of accelerator technologies which have the potential to revolutionise the cost, compactness and efficiency of such systems. The main element of the infrastructure will be a high performance and flexible electron beam injector facility, feeding customised state-of-the-art testing enclosures and associated support infrastructure. The facility operating parameters and implementation status will be described, along with primary areas of commercialised technology development opportunities.  
 
THPPR072 High Power of 10 MeV, 25 kW Electron LINAC for Irradiation Applications electron, linac, simulation, radiation 4142
 
  • Y.J. Pei, G. Feng, Y. Hong, K. Jin, S. Lu, L. Shang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Using the electron beam to sterilize medical products and cosmetics, and food preservation and so on, has become important and efficient manners recently in number and variety. This paper describes the design, construction, and commissioning of a high power electron LINAC which can provide beam energy of 10 MeV, beam power of 25 kW. The paper also gives beam dynamic simulation results where beam loading effect was taken into account, and running parameters.