Keyword: coupling
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MOPWA015 Lattice Correction using LOCO for the ThomX Storage Ring quadrupole, optics, lattice, storage-ring 117
 
  • I. Chaikovska, C. Bruni, S. Chancé, A. Variola, J.F. Zhang
    LAL, Orsay, France
  • A. Loulergue
    SOLEIL, Gif-sur-Yvette, France
  
  Funding: Work is supported by the French Agence Nationale de la Recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI
ThomX is a compact Compton based X-ray source under construction at LAL in Orsay (France). The ThomX accelerator facility is composed by a 50-70 MeV linac driven by 3 GHz RF gun, a transfer line and a 18 meters long Storage Ring (SR). The Compton backscattering at each revolution between the 1 nC electron bunch and the 25 mJ laser pulses stacked in the Fabry-Perot cavity results in the production of ~1013 photons per second with energies in the X-ray regime. This high flux of the X-rays strongly depends on the quality (beam sizes) of the electron beam at the interaction point. To guarantee this, a good knowledge and quality of the linear lattice of the ThomX SR are required. Nowadays, LOCO (Linear Optics from Closed Orbits) is a well-known and widely used algorithm to measure and restore the linear optics of the SRs and ensure the designed performances. Comparing the measured and model orbit response matrices, the linear lattice can be restored by retuning the quadrupole gradients. In this paper, we report on the LOCO analysis of the ThomX SR taking into account simulated misalignment, calibration and field errors. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA015  
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MOPWA040 Virtual Cavity Probe Generation using Calibrated Forward and Reflected Signals cavity, controls, flattop, laser 200
 
  • S. Pfeiffer, V. Ayvazyan, J. Branlard, L. Butkowski, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  • R. Rybaniec
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  
  The European X-ray free electron laser requires a high-precision control of accelerating fields to ensure a stable photon generation. Its low level radio frequency system, based on the MicroTCA.4 standard, detects the probe, forward and reflected signals for each cavity. While the probe signal is used to control the accelerating fields, a combination of the forward and reflected signals can be used to compute a virtual probe, whose accuracy is comparable to the directly sampled probe. This requires the removal of cross-coupling effects between the forward and reflected signals. This paper presents the precise generation of a virtual probe using an extended method of least squares. The virtual probe can then be used for precise field control in case the probe signal is missing or corrupted. It can also be used to detect any deviation from the nominal probe profile.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA040  
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MOPWA060 THE COUPLING IMPEDANCE MEASUREMENT OF THE FAST EXTRACTION KICKER IN CSNS/RCS * impedance, kicker, extraction, proton 262
 
  • L. Huang, Y.D. Liu, S. Wang
    IHEP, Beijing, People's Republic of China
  
  Rapid Cycling Synchrotron of the China Spallation Neutron Source is a high intensity proton accelerator. In order to high intensity beam operation, the beam coupling impedance of the extracted kickers must be controlled. The measurement of longitudinal and transverse coupling impedance of the extraction kicker is described.
Supported by National Natural Science Foundation of China (11175193, 11275221) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA060  
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MOPJE015 Compensations of the DEPU Effects at the SSRF Storage Ring quadrupole, injection, dynamic-aperture, sextupole 307
 
  • M.Z. Zhang, B.C. Jiang, J.H. Tan, S.Q. Tian, M. Zhang, Q.L. Zhang
    SINAP, Shanghai, People's Republic of China
  
  A paired APPLE-II type Ellipsoid Polarized Undulator（DEPU）has been installed in the SSRF storage ring which can be mechanically switched between two undulators with difference period length. One of them get notable effects on the optics including CODs, tune, coupling and dynamic aperture. We report in this paper, feed forward tables of correctors, quadrupoles and skew quarupoles are used for the optics correction and sextupole optimization is used for the dynamic aperture recovery.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE015  
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MOPJE034 Low Emittance Tuning for the CLIC Damping Rings emittance, quadrupole, lattice, sextupole 356
 
  • J. Alabau-Gonzalvo, F. Antoniou, Y. Papaphilippou
    CERN, Geneva, Switzerland
  
  A study on the sensitivity of the CLIC Damping Ring lattice to different sources of misalignment is presented. Dipole and quadrupole rolls, quadrupole and sextupole vertical offsets are considered, as well as the impact of a finite BPM resolution. The result of this study defines a low emittance tuning procedure and establishes alignment tolerances to preserve the vertical emittance below the design value (1 pm·rad). Non-linear dynamics studies including dynamic aperture and frequency maps are shown and synchrotron radiation effects are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE034  
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MOPJE038 Impedance Studies of the LHC Injection Kicker Magnets for HL-LHC impedance, kicker, injection, simulation 370
 
  • H.A. Day, M.J. Barnes, L.M.C. Feliciano
    CERN, Geneva, Switzerland
  
  The LHC injection kicker magnets (MKIs) experienced strong heating during the first operational run, identified as being caused by power loss due to wakefields induced by stored beam. Studies of the beam coupling impedance of the beam screen, a series of conductors embedded in a ceramic tube placed in the ferrite yoke to screen the ferrite from the beam, resulted in new design offering improved screening: this is predicted to reduce the heating to acceptable levels for operation with 25ns beam during Run 2 of the LHC. However higher beam intensities proposed for HL-LHC operation are predicted to again cause strong heating to occur. Further studies have been carried out to reduce the beam induced power loss by optimising the beam screen design, some key results and findings of which are presented here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE038  
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MOPJE053 NSLS-II Beam Lifetime Measurements and Modeling scattering, cavity, emittance, lattice 416
 
  • B. Podobedov, W.X. Cheng, Y. Hidaka, H.-C. Hseuh, G.M. Wang
    BNL, Upton, Long Island, New York, USA
  
  NSLS-II is a recently constructed 3 GeV synchrotron light source with design horizontal emittance values in sub-nm range. Achieving good beam lifetime is critically important for NSLS-II as it is closely tied in to such important operational aspects as top-off injection frequency, injector components wear, radiation protection and control, and others. In this paper we present lifetime-related commissioning results, describe our present understanding of beam lifetime at NSLS-II and extrapolate our models to the fully built-up machine operating at 500 mA design beam current.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE053  
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MOPJE054 Developments of the Segment-by-Segment Technique for Optics Corrections in the LHC optics, simulation, betatron, quadrupole 419
 
  • A. Langner, J.M. Coello de Portugal, P.K. Skowroński, R. Tomás
    CERN, Geneva, Switzerland
  
  Optics correction algorithms will become even more critical for the operation of the LHC at 6.5 TeV. For the computation of local corrections the segment-by-segment technique is used. We present improvements to this technique and an advanced error analysis, which increase the sensitivity for finding local corrections. Furthermore, we will investigate limitations of this method for lower beta-star optics as they will be used in the high-luminosity LHC (HL-LHC) upgrade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE054  
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MOPJE060 BBA and Coupling Correction at CLIC RTML emittance, quadrupole, dipole, alignment 442
 
  • Y. Han, L. Ma
    SDU, Shandong, People's Republic of China
  • A. Latina, D. Schulte
    CERN, Geneva, Switzerland
  
  The CLIC Ring To Main Linac (RTML) must transport the electron and the positron bunches through more than 20 km of beamlines with minimal emittance growth. The turnaround loops (TAL) are one of the most critical sections, featuring a lattice designed to minimize emittance growth due to synchrotron radiation emission and chromaticity, while being isochronous to avoid bunch lengthening. With such a design, the impact of static imperfections like element misalignment is particularly critical. In this paper a study of the Beam-Based Alignment (BBA) techniques in the TAL of the CLIC RTML is presented. In order to reduce the emittance growth, the one-to-one and dispersion-free corrections have been tested. The results showed that the emittance growth budgets can be met both in the horizontal and vertical planes. The impact of coupling errors due to magnets rolls on the emittance has also been studied and a coupling correction section has been designed and inserted in the lattice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE060  
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MOPJE082 Analytical Approach to the Beam-Beam Interaction with the Hourglass Effect luminosity, detector, collider, framework 510
 
  • M.P. Crouch, R.B. Appleby
    UMAN, Manchester, United Kingdom
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: STFC HL-LHC
The HL-LHC upgrade will allow higher luminosities to be reached in the LHC. To achieve higher luminosities the β-function at the IP is decreased, which in turn will result in the hourglass effect becoming more prominent as the transverse bunch sizes become comparable to the length of the bunch. This effect reduces the luminosity since not all particles in the bunch will collide at the minimum IP. The standard derivation of the electric and magnetic fields of the beam-beam interaction is that undertaken by Bassetti and Erskine. The derivation by Bassetti Erskine does not include a coupling between bunch planes. When the transverse bunch sizes are comparable to the length of the bunch the magnitude of the transverse kick will be dependent on the longitudinal position. Currently only numerical methods are available to evaluate this effect. Here a theoretical framework is outlined that provides an analytical approach to derive the electric field for the beam-beam interaction with a coupling between the transverse and longitudinal planes. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE082  
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MOPJE083 Implications of Manufacturing Errors on Higher Order Modes and on Beam Dynamics in the ESS Linac HOM, cavity, linac, wakefield 514
 
  • A. Farricker, R.M. Jones
    UMAN, Manchester, United Kingdom
  • S. Molloy
    ESS, Lund, Sweden
  
  The European Spallation Source (ESS) in Lund, Sweden, will be a facility for fundamental physics studies of atomic structure using a spallation source of unparalleled brightness. To achieve this end, protons will be accelerated up to 2 GeV using a suite of cavities. Here we focus on the Medium Beta (β =0.67) elliptical superconducting cavities and we assess the influence of potential errors in fabrication to shift eigenmode frequencies onto an harmonic of the bunch frequency. If this occurs, and countermeasures are not adopted, the beam quality will be appreciably diluted *. We provide details on the geometrical parameters which are particularly sensitive to frequency errors from intensive finite element simulations of the electromagnetic fields. A circuit model is also employed to rapidly assess the shift in the eigenmodes from their anticipated design values due a variety of potential errors.
* Aaron Farricker et al, Physics Procedia, Proceedings of HOMSC14 (in press), 2014. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE083  
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MOPMA010 Commissioning Simulations for the APS Upgrade Lattice lattice, simulation, quadrupole, closed-orbit 553
 
  • V. Sajaev, M. Borland
    ANL, Argonne, Ilinois, 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.
A hybrid seven-bend-achromat lattice has been proposed for the APS upgrade that will feature very strong focusing elements and relatively small vacuum chamber. Achieving design lattice parameters during commissioning will need to be accomplished in a short period of time to minimize dark time for APS users. We describe here start-to-end simulation of the machine commissioning beginning from first-turn trajectory correction, performing orbit and lattice correction, and finally evaluating nonlinear performance of the corrected lattice in terms of dynamic aperture and lifetime. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA010  
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MOPMA013 Experience with Round Beam Operation at the Advanced Photon Source emittance, operation, resonance, storage-ring 562
 
  • A. Xiao, L. Emery, V. Sajaev, B.X. Yang
    ANL, Argonne, Ilinois, 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
Very short Touschek lifetime becomes a common issue for next-generation ultra-low emittance storage ring light sources. In order to reach a longer beam lifetime, such a machine often requires operating with a vertical-to-horizontal emittance ratio close to an unity, i.e. a ‘‘round beam''. In tests at the APS storage ring, we determined how a round beam can be reached experimentally. Some general issues, such as beam injection, optics measurement and corrections, and orbit correction have been tested also. To demonstrate that a round beam was achieved, the beam size ratio is calibrated using beam lifetime measurement. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA013  
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MOPMA040 Analysis of Beam Transverse Instabilities at Fermilab dipole, space-charge, impedance, quadrupole 633
 
  • T. Zolkin
    University of Chicago, Chicago, Illinois, USA
  
  The transverse beam dynamics in Fermilab Recycler ring has been analyzed using SCHARGEV Vlasov solver. In the first part of paper we discuss how SCHARGEV analyses collective instabilities for Gaussian bunch with strong space charge in resistive impedance environment. In the second part the bunched beam dynamics is studied depending on head-tail phase and damper gain. An example for Fermilab Recycler is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA040  
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MOPMN001 Linear Optics and Coupling Correction with Turn-by-turn BPM Data lattice, quadrupole, optics, target 698
 
  • X. Huang
    SLAC, Menlo Park, California, USA
  • X. Yang
    BNL, Upton, Long Island, New York, USA
  
  We propose a method to measure and correct storage ring linear optics and coupling with turn-by-turn BPM data. The independent component analysis (ICA) is used to obtain the amplitudes and phase advances of the betatron normal modes, which are compared to their counterparts derived from the lattice model. By fitting the model to the data with quadrupole and skew quadrupole variables, the linear optics and coupling of the machine can be obtained. Simulation demonstrates that errors in the lattice and BPM parameters can be recovered with this method. Experiments on the NSLS-II storage ring show that it can find the same optics as the linear optics from closed orbit (LOCO) method.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN001  
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MOPHA033 Physical Parameter Identification of Cross-Coupled Gun and Buncher Cavity at REGAE gun, resonance, cavity, higher-order-mode 857
 
  • A.S. Nawaz, H. Werner
    TUHH, Hamburg, Germany
  • M. Hoffmann, S. Pfeiffer, H. Schlarb
    DESY, Hamburg, Germany
  
  A reasonable description of the system dynamics is one of the key elements to achieve high performance control for accelerating modules. This paper depicts the system identification of a cross-coupled pair of cavities for the Relativistic Electron Gun for Atomic Exploration - REGAE. Two normal conducting copper cavities driven by a single RF source accelerate and compress a low charge electron bunch with sub 10 fs length at a repetition rate up to 50 Hz. It is shown how the model parameters of the cavities and the attached radio frequency subsystem are identified from data generated at the REGAE facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA033  
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MOPHA053 Radiation Measurements of a Medical Particle Accelerator Through a Passive Resonant Cavity cavity, linac, detector, radiation 917
 
  • A. Leggieri, F. Di Paolo, D. Passi
    Università degli Studi di Roma "Tor Vergata", Roma, Italy
  • A. Ciccotelli, S. De Stefano, G. Felici, F. Marangoni
    S.I.T., Aprilia, Italy
  
  Beam monitoring system are required by technical standards for the real time measurement of the dose delivered to the target while the beam is crossing them * **. Traditional beam current monitoring systems are based on ionization chambers and requires high voltage biases *** ****. This study investigates on the measurements of the electron beam current emitted by a medical electron linear accelerator using the power exchange of the beam current with a passive resonant cavity ***** placed at the output interface of the accelerator. The cavity is magnetically coupled with a coaxial transmission line loaded on a microwave envelope detector and its output signal has been documented while receiving several electron currents. This paper shows the complete equivalency, in terms of global performance, of the current revelation performed by exploiting the cavity-beam interaction principle with the classical technology, based on ionization chambers, however without need of high voltage. The most important point is that the resonant cavity system, by measuring the beam current, gives a direct measurement of a physical observable quantity directly related with the dose deposed by the beam.
* EN 60601-2-1, 2009.
** A.P. Turner, 1979.
*** V.L. Uvarov, 1997.
**** M. Ruf∗, 2014.
***** J.B. Rosenzweig, 2003 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA053  
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MOPTY001 Development of Wideband BPM for Precise Measurement of Internal Bunch Motion impedance, feedback, synchrotron, network 937
 
  • K.G. Nakamura
    Kyoto University, Kyoto, Japan
  • Y.H. Chin, T. Koseki, T. Obina, M. Okada, M. Tobiyama, T. Toyama
    KEK, Ibaraki, Japan
  • Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  Funding: This work was supported by MEXT KAKENHI Grant Number 25105002, Grant-in-Aid for Scientific Research on Innovative Areas titled “ Unification and　Development of the Neutrino Science Frontier”
To suppress intra-bunch oscillations and to reduce particle losses, the intra-bunch feedback (IBFB) system has been developed in 2014 for the J-PARC Main Ring (MR). A new BPM was also installed to the MR for the IBFB system. This BPM has a sufficient frequency response and position sensitivity(up to 1.5GHz within 15% fluctuation ). However, a better performance may be needed in future for more precise analysis of internal motions (e.g. due to an electron cloud). We report the development of the BPM and precise measurement results of the BPM characteristics. We also report simulation studies of the digital equalizer which helps to reconstructs the beam shape from beam signals. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY001  
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MOPWI005 Emittance and Optics Measurements on the Versatile Electron Linear Accelerator at Daresbury Laboratory space-charge, quadrupole, emittance, gun 1153
 
  • C.P. Topping, D.J. Scott, A. Wolski
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S.D. Barrett, C.P. Topping, A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • B.L. Militsyn, D.J. Scott
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide a high quality electron beam for accelerator systems development, as well as industrial and scientific applications. Currently, the RF gun can deliver short (of order a few ps) bunches with charge in excess of 250 pC at up to 5.0 MeV/c beam momentum. Measurement of the beam emittance and optics in the section immediately following the gun is a key step in tuning both the gun and the downstream beamlines for optimum beam quality. We report the results of measurements (taking account of coupling and space charge) indicating normalised emittances of order 0.5 μm at low bunch charge.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI005  
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MOPWI014 Design and Development for the Next Generation X-ray Beam Position Monitor System at the APS undulator, background, electron, photon 1175
 
  • B.X. Yang, G. Decker, Y. Jaski, S.-H. Lee, M. Ramanathan, N. Sereno, F. Westferro
    ANL, Argonne, Ilinois, USA
  
  Funding: Work performed at Argonne National Laboratory, operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357.
The proposed Advanced Photon Source (APS) Upgrade will bring storage-ring beam sizes down to several micrometers and require x-ray beam directional stability in 100 nrad range for undulator power exceeding 16 kW. The next generation x-ray beam position monitors (XBPMs) are designed to meet these requirements. We present first commissioning data on the recently installed grazing-incidence insertion device x-ray beam position monitor (GRID-XBPM) based on Cu K-edge x-ray fluorescence from limiting absorbers of the front end for two inline undulators. It demonstrated a 50-fold improvement for signal-to-background ratio over existing photoemission-based XBPMs. Techniques for calibrating the XBPMs will be discussed. We will also present a new XBPM design based Compton scattering from diamond blades. This XBPM is designed for less powerful undulators such as the APS canted-undulator beamlines where each undulator generates < 10 kW of beam power. We will discuss the thermal design of the blade, the optics design of the detector assembly, and computer simulations of expected response to the x-ray beam. Test data of the prototype may be presented if available. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI014  
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MOPWI030 Low Emittance Tuning With a Witness Bunch betatron, emittance, lattice, storage-ring 1223
 
  • D. L. Rubin, R.E. Meller, J.P. Shanks
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: Work supported by NSF PHY-1416318, PHY-0734867 and PHY-1002467, and DOE DE-FC02-08ER- 41538 and DE-SC0006505
Electron positron damping rings and colliders will require frequent tuning to maintain ultra-low vertical emittance. Emittance tuning begins with precision beam based measurement of lattice errors (orbit, transverse coupling, and dispersion) followed by compensation with corrector magnets. Traditional techniques for measuring lattice errors are incompatible with simultaneous operation of the storage ring as light source or damping ring. Dedicated machine time is required. The gated tune tracker (the device that drives the beam at the normal mode frequencies) and the bunch-by-bunch, turn-by-turn beam position monitor system developed at CESR are integrated to allow synchronous detection of phase. The system is capable of measuring lattice errors during routine operation. A single bunch at the end of a train of arbitrary length, is designated as the witness. The witness bunch alone is resonantly excited, and the phase and amplitude of the witness is mea- sured at each of the 100 beam position monitors. Lattice errors are extracted from the measurements. Corrections are then applied. The emittance of all of the bunches in the train is measured and the effectiveness of the correction procedure demonstrated. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI030  
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MOPWI047 Architectural Improvements and New Processing Tools for the Open XAL Online Model cavity, simulation, hardware, software 1262
 
  • C.K. Allen, T.A. Pelaia II
    ORNL, Oak Ridge, Tennessee, USA
  • J.M. Freed
    University of South Carolina, Columbia, USA
  
  Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
The Open XAL online model is the component of Open XAL* providing accelerator modeling dynamic synchronization to live hardware. Several significant architectural enhancements and feature additions have been made concerning the handling and processing of simulation data. The major structural change is the creation of a single class Trajectory<> that manages all simulation data. Another significant design change was the development of standard tools for processing simulation results. One may obtain machine parameters such as fixed orbit, phase advance, dispersion, etc., or beam-based calculations such as RMS size and centroid location simply by passing simulation results, i.e. a Trajectory<> object, to these computation tools. Finally, the ability to fully create composite modeling elements was implemented in the online model. Specifically, accelerator hardware can be modeled as a collection of constituent modeling elements. This sub-structure capability is extremely useful for modeling RF cavities consisting of coupled RF gaps coupled and drift spaces. We present an overview of the new architecture and how it is used when building applications.
* http://xaldev.sourceforge.net/ 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI047  
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TUAB1 Correction of Nonlinear Coupling Resonances in the SPring-8 Storage Ring resonance, injection, octupole, sextupole 1329
 
  • M. Takao, K. Fukami, Y. Shimosaki, K. Soutome
    JASRI/SPring-8, Hyogo-ken, Japan
  
  The correction of the lattice nonlinearity of the storage rings is crucial for the enlargement of the dynamic aperture of the storage rings, which in general leads to the higher injection efficiency and the longer lifetime. At the SPring-8 storage ring, it is realized that the higher order coupling resonances are considerably excited. After the usual correction of the nonlinear dynamics in terms of the normal sextupole magnets, we suppress one of the resonances by using the skew sextupole magnets for the purpose of further improving the dynamic aperture. As a result of the correction by the skew sextupoles, the reckoned improvement of the injection efficiency and the lifetime is achieved. Furthermore, at the SPring-8 storage ring, it is observed that the error magnetic field of a particular insertion device (ID) excites the higher nonlinear coupling resonance of the skew octupoles, which remarkably deteriorates the injection efficiency. In order to correct the coupling resonance, we have installed the octupole magnets at the ID, by which we restore the injection efficiency.  
slides icon Slides TUAB1 [3.275 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUAB1  
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TUPWA045 Further Investigations on the MESA injector linac, simulation, space-charge, experiment 1515
 
  • R.G. Heine, K. Aulenbacher, S. Friederich, C. Matejcek, F. Schlander
    IKP, Mainz, Germany
  
  Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA"
The MESA ERL to be build at Mainz in the next years is a multi turn recirculating linac with beam currents of up to 10 mA. The dynamic range of the beam currents demanded by the experiments is of at least two orders of magnitude. This is a special challenge for the layout design of an injector. In this paper we present the current status of the design of the injector linac called MAMBO (MilliAMpereBOoster). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA045  
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TUPJE042 Transverse Tunes Determination from Mixed BPM Data betatron, operation, storage-ring, injection 1709
 
  • P. Zisopoulos, F. Antoniou, Y. Papaphilippou
    CERN, Geneva, Switzerland
  • E. Hertle, A.-S. Müller
    KIT, Eggenstein-Leopoldshafen, Germany
  
  Decoherence due to non-zero chromaticity and/or amplitude dependent tune-shift, but also damping mechanisms can affect the accurate tune determination by leaving a limited number of turns for frequency analysis of the turn by turn (TbT) position data. In order to by-pass these problems, Fourier analysis of mixed TBT data from all BPMs can be employed. The approach is applied in two different accelerators, a hadron collider as the LHC and a synchrotron light source as the ANKA storage ring. The impact in the accuracy of the method of missing BPM data is also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE042  
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TUPHA009 NSLS-II Storage Ring Coupling Measurement and Correction betatron, quadrupole, kicker, storage-ring 1983
 
  • G.M. Wang, Y. Li, T.V. Shaftan, L. Yang, L.-H. Yu
    BNL, Upton, Long Island, New York, USA
  
  The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. To achieve the goal, 8 pm level vertical beam emittance, the coupling due to the misalignment in quads and vertical beam offset in sextuples must be corrected. Traditional method, based on response matrix, such as LOCO, is wildly used measure and corrects the coupling. In this paper, we present a new method to measure and correct the coupling with BPMs TBT data from fast kickers or pingers excited betatron oscillation. Besides the TBT data, other method, is also used to characterize the coupling.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPHA009  
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TUPHA013 Skew-Quad Parametric-Resonance Ionization Cooling: Theory and Modeling resonance, betatron, emittance, focusing 1993
 
  • A. Afanasev
    GWU, Washington, USA
  • Y.S. Derbenev, V.S. Morozov, A.V. Sy
    JLab, Newport News, Virginia, USA
  • R.P. Johnson
    Muons, Inc, Illinois, USA
  
  Funding: This work was supported in part by U.S. DOE STTR Grants DE-SC0005589 and DE-SC0007634.
Muon beam ionization cooling is a key component for the next generation of high-luminosity muon colliders. To reach adequately high luminosity without excessively large muon intensities, it was proposed previously to combine ionization cooling with techniques using a parametric resonance (PIC). Practical implementation of PIC proposal is a subject of this report. We show that an addition of skew quadrupoles to a planar PIC channel gives enough flexibility in the design to avoid unwanted resonances, while meeting the requirements of radially-periodic beam focusing at ionization-cooling plates, large dynamic aperture and an oscillating dispersion needed for aberration corrections. Theoretical arguments are corroborated with models and a detailed numerical analysis, providing step-by-step guidance for the design of Skew-quad PIC (SPIC) beamline. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPHA013  
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TUPTY042 Non-linear Coupling Studies in the LHC octupole, hadron, collider, simulation 2105
 
  • T. Persson, Y.I. Levinsen, E.H. Maclean, R. Tomás
    CERN, Geneva, Switzerland
  • E.H. Maclean
    JAI, Oxford, United Kingdom
  
  The amplitude detuning has been observed to decrease significantly as the horizontal and vertical tunes are approaching each other. This effect is potentially harmful since it might cause a loss of Landau damping, hence giving rise to instabilities. The measured tune split (Qx-Qy) versus amplitude is several times bigger than what can be explained with linear coupling. In this paper we present studies performed to identify the dominant sources of the non-linear coupling observed in the LHC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY042  
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TUPTY046 Impact of Beam Losses in the LHC Collimation Regions collimation, simulation, proton, dipole 2116
 
  • E. Skordis, R. Bruce, F. Cerutti, A. Ferrari, P.D. Hermes, A. Lechner, A. Mereghetti, P.G. Ortega, S. Redaelli, V. Vlachoudis
    CERN, Geneva, Switzerland
  
  The upgrade of the LHC energy and brightness, from the 2015 restart at close to design energy until the HL-LHC era with considerable hardware development and layout renewal, poses tight challenges in terms of machine protection. The collimation insertions and especially the one dedicated to betatron cleaning (IR7), where most of the beam halo is intercepted to spare from losses the cold sectors of the ring, will be subject to a significant increase of radiation load, whose leakage to the nearby dispersion suppressors must be kept sustainable. The past LHC run, while displaying a remarkable performance of the collimation system, offered the opportunity for a demanding benchmarking of the complex simulation chain describing the beam losses and the macroscopic effects of the induced particle showers, this way strengthening the confidence in the reliability of its predictions. This paper discusses the adopted calculation strategy and its evolution options, showing the accuracy achieved with respect to Beam Loss Monitor measurements in controlled loss scenarios. Expectations at design energy, including lifetime considerations concerning critical elements, will also be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY046  
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TUPWI016 Gantry 3: Further Development of the PSI PROSCAN Proton Therapy Facility controls, proton, cyclotron, dipole 2275
 
  • A. Koschik
    PSI, Villigen, Villigen, Switzerland
  • C. Bula, J.P. Duppich, A. Gerbershagen, M. Grossmann, J.M. Schippers, J. Welte
    PSI, Villigen, Switzerland
  
  PSI and its Center for Proton Therapy (CPT) is extending its research capabilities in the field of proton therapy and pencil beam scanning technology. Gantry 3 will be an additional treatment room at the PROSCAN facility at PSI, Villigen, Switzerland. It will feature a 360 degree scanning Gantry delivered by Varian Medical Systems. The Gantry design is based on Varian technology, which will be combined with advanced PSI active scanning technology. The further development of fast energy switching as well as precise spot and continuous line scanning irradiation modes are main research topics at the PROSCAN facility. A major challenge with Gantry 3 is the link of the existing PSI PROSCAN system with the Varian PROBEAM system, while retaining the system integrity and high performance level. Additionally, Gantry 3 will be installed and commissioned while keeping the other treatment rooms (Gantry 1, Gantry 2, Optis 2) in full operation. The current development and project status is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI016  
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WEPWA060 Interaction of a Volumetric Metamaterial Structure with an Electron Beam electron, wakefield, radiation, acceleration 2640
 
  • X.Y. Lu, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  Funding: The U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0010075 and the Air Force Office of Scientific Research under MURI Grant Number FA550-12-1-0489.
A volumetric metallic metamaterial structure with a cubic unit cell is introduced. The unit cells can naturally fill all of space without additional substrates or waveguides. The structure can support a negative longitudinal electric mode that can couple to an electron beam. The dispersion characteristics of the unit cell are modeled by the effective medium theory with spatial dispersion. The theory also predicts the correct resonant frequencies of the emitted radiation excited by an electron beam traversing the structure. In the wakefield simulations, a backward radiation pattern is observed. The proposed metamaterial can be applied to beam diagnostics and wakefield acceleration. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA060  
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WEPWA061 High-Gradient Testing of Metallic Photonic Band-gap (PBG) and Disc-Loaded Waveguide (DLWG) Structures at 17 GHz operation, flattop, diagnostics, wakefield 2643
 
  • B.J. Munroe, M.A. Shapiro, R.J. Temkin, J.X. Zhang
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  Funding: This work supported by the DOE, Office of High Energy Physics, Grant No. DE-SC0010075
Photonic Band-gap (PBG) structures continue to be a promising area of research for future accelerator structures. Previous experiments at 11 GHz have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. A metallic single-cell standing-wave PBG structure has been tested at 17 GHz at MIT to investigate how breakdown probability scales with frequency in these structures. A single-cell standing-wave disc-loaded waveguide (DLWG) was also tested at MIT as a reference structure. The PBG structure achieved greater than 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.1 *10-1 /pulse/m. The DLWG structure achieved 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.2 *10-1 /pulse/m, the same as the PBG structure within experimental error. These tests were conducted at the MIT structure test stand, and represent the first long-pulse breakdown testing of accelerator structures above X-Band. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA061  
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WEPWA062 Design and High-Power Testing of a Hybrid Photonic Band-Gap (PBG) Accelerator Structure at 17 GHz cavity, simulation, lattice, flattop 2646
 
  • J.X. Zhang, A.M. Cook, B.J. Munroe, M.A. Shapiro, R.J. Temkin, H. Xu
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics under Award Number DE-SC0010075.
An overmoded hybrid Photonic Band Gap (HPBG) structure used as an accelerator cavity has been theoretically designed and high power tested at 17.1 GHz. The HPBG structure consists of a triangular lattice of dielectric (sapphire) and metallic (copper) rods. Due to the frequency selectivity, the hybrid PBG cavity can be operated in a TM02 mode. The maximum surface fields are on the triple point of the innermost row of the sapphire rods. The relatively high value of the surface fields resulted in a high breakdown rate (BDR) at a low gradient in the HPBG structure. Breakdown damage on the triple point edge and the metallization of copper onto the sapphire surface have been observed in the post-testing images. An improved HPBG design, that reduces the peak fields, has been developed. It will be built and tested in an effort to improve the HPBG performance. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA062  
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WEPJE008 Experimental Study of Wakefields in an X-band Photonic Band Gap Accelerating Structure wakefield, HOM, higher-order-mode, electron 2689
 
  • E.I. Simakov, S. Arsenyev, C.E. Buechler, R.L. Edwards, W.P. Romero
    LANL, Los Alamos, New Mexico, USA
  • M.E. Conde, G. Ha, C.-J. Jing, J.G. Power, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  Funding: This work is supported by U.S. Department of Energy (DOE) Office of Science Early Career Research Program.
We designed an experiment to conduct a detailed investigation of higher order mode spectrum in a room-temperature traveling-wave photonic band gap (PBG) accelerating structure at 11.7 GHz. It has been long recognized that PBG structures have great potential in reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in room-temperature PBG structures was conducted at MIT in 2005. Since then, the importance of that device has been recognized by many research institutions. However, the full experimental characterization of the wakefield spectrum in a beam test has not been performed to date. The Argonne Wakefield Accelerator (AWA) test facility at the Argonne National Laboratory represents a perfect site where this evaluation could be conducted with a single high charge electron bunch and with a train of bunches. Here we describe fabrication and tuning of PBG cells, the final cold-test of the traveling-wave accelerating structure, and the results of the beam testing at AWA. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE008  
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WEPJE013 A New Accelerating Mode in a Silicon Woodpile Structure and Its High-efficiency Power Coupler Design laser, acceleration, simulation, electron 2702
 
  • Z. Wu, R.J. England, C. Lee, C.-K. Ng, K.P. Wootton
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by U.S. Department of Energy under Grants DE-AC02-76SF00515, DE-FG02-13ER41970 and by DARPA Grant N66001-11-1-4199.
Silicon woodpile photonic crystals provide a base structure that can be used to build a three-dimensional dielectric waveguide system for high-gradient laser-driven acceleration. A new woodpile waveguide design that hosts a phase synchronous, centrally confined accelerating mode with ideal Gaussian transverse profile is proposed. Comparing with previously discovered silicon woodpile accelerating modes, this mode shows advantages in better beam loading and higher achievable acceleration gradient. Several travelling-wave coupler design schemes developed for multi-cell RF cavity accelerators are adapted to the woodpile accelerator coupler design based on this new accelerating mode. A forward-wave-coupled, highly efficient silicon woodpile accelerator is achieved. Simulation shows high efficiency of over 70% of the drive laser power coupled to this fundamental woodpile accelerating mode, with less than 15% backward wave excitation. The estimated acceleration gradient, when the coupler structure is driven at the damage threshold fluence of silicon at its operating 1.506 um wavelength, can reach roughly 185 MV/m. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE013  
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WEPJE015 Muon Tracking Studies in a Skew Parametric Resonance Ionization Cooling Channel resonance, quadrupole, betatron, focusing 2705
 
  • A.V. Sy, Y.S. Derbenev, V.S. Morozov
    JLab, Newport News, Virginia, USA
  • A. Afanasev
    GWU, Washington, USA
  • R.P. Johnson
    Muons, Inc, Illinois, USA
  
  Funding: This work was supported in part by U.S. DOE STTR Grant DE-SC0005589. This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Skew Parametric-resonance Ionization Cooling (SPIC) is an extension of the Parametric-resonance Ionization Cooling (PIC) framework that has previously been explored as the final 6D cooling stage of a high-luminosity muon collider. The addition of skew quadrupoles to the PIC magnetic focusing channel induces coupled dynamic behavior of the beam that is radially periodic. The periodicity of the radial motion allows for the avoidance of unwanted resonances in the horizontal and vertical transverse planes, while still providing periodic locations at which ionization cooling components can be implemented. A first practical implementation of the magnetic field components required in the SPIC channel is modeled in MADX. Dynamic features of the coupled correlated optics with and without induced parametric resonance are presented and discussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE015  
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WEPMA026 Higher Order Mode Propagation and Damping Studies on Axisymmetric Superconducting Multicell RF-Resonators cavity, factory, damping, higher-order-mode 2812
 
  • B.D. Isbarn, B. Riemann, M. Sommer, T. Weis
    DELTA, Dortmund, Germany
  
  Funding: Work supported by the BMBF under contract no. 05K13PEB
Higher order mode (HOM) propagation and damping is a major concern in feasibility studies regarding the upcoming upgrade of BESSY II, named BESSY-VSR*, which involves the utilization of superconducting multicell RF-resonators in a storage ring while maintaining a reasonably high beam current typical for third generation synchrotron radiation facilities. In addition to the computation of the typical figures of merit, we focus on studies of the mode propagation in axisymmetric structures. Due to the focus on axisymmetric studies we are able to use 2D codes to investigate in eigenmodes with substantial higher frequencies than usually considered with full 3D codes in parametric studies. In this work we present preliminary studies involving mode propagation in superconducting elliptical multicell cavities.
* G. Wüstefeld et al., Proc. of IPAC'11, San Sebastián, THPC014 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA026  
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WEPMA029 Design of a Normal Conducting Cavity for Arrival Time Stabilization at FLASH cavity, wakefield, simulation, HOM 2818
 
  • M. Fakhari, K. Flöttmann, S. Pfeiffer, H. Schlarb
    DESY, Hamburg, Germany
  • J. Roßbach
    Uni HH, Hamburg, Germany
  
  It has been shown, that beam-based feedback loops stabilize the bunch arrival time in the femtoseconds range. However, further minimizing the bunch arrival time jitter requires a faster actuator that is a normal conducting cavity with higher bandwidth compared to narrow-band superconducting cavities. We present the design of a 4-cell normal conducting cavity that is going to be used in a fast beam-based feedback at free-electron laser FLASH at Hamburg. The input power will be injected to the cavity via a loop coupler from the side of the first cell. The operating frequency of the designed cavity is about 3 GHz with an adjustable bandwidth. The long range longitudinal wakefield calculation results are reported to investigate the cavity performance for multi-beam operation up to 3 MHz bunch repetition rate. The results declare that the influence of the long range wakefield on the arrival time jitter is less than 1 fs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA029  
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WEPMA047 MHI's Production Activities of Accelerator Components network, status, LLRF, vacuum 2873
 
  • N. Shigeoka, S. Miura
    MHI, Hiroshima, Japan
  
  Mitsubishi Heavy Industries (MHI) is manufacturing various types of accelerator components. Recent production activities, mainly in a field of a normal conducting RF, will be reported in this presentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA047  
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WEPMN010 Analysis of the Electromagnetic Field in the Coupler of Normal Temperature Travelling-Wave Accelerating Tube cavity, electromagnetic-fields, emittance, simulation 2934
 
  • X. He, M. Hou
    IHEP, Beijing, People's Republic of China
  • S. Shu
    Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
  
  With the developed requirement of the beam quality in modern accelerators, rapid development of all kinds of accelerating structures with different frequencies and materials have been achieved. However, the normal temperature travelling-wave (TW) accelerating structures which are widely used in Free Electron Laser (FEL) are still indispensable. For reducing the beam emittance, it is very important to optimize the symmetry of the high-order electromagnetic field in the coupler of such accelerating structures. In this paper, the symmetry of the electromagnetic field in TW accelerator couplers using different coupling mechanisms was analysed. A lot of design optimization as well as the result analysis work has been done for the three kinds of commonly used waveguide-coupled TW accelerating structures: single-feed electrical-coupling, dual-feed electrical-coupling using magic tee in feeding waveguide and dual-feed magnetic-coupling using J-type feeding waveguide. Finally, basing on lots of simulation results and the performances during the fabrication, measurement and RF conditioning of these three kinds of structures, the J-type racetrack coupler type is regarded as the best choice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN010  
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WEPMN011 RF Modulation Studies on the S-Band Pulse Compressor cavity, flattop, klystron, simulation 2937
 
  • S. Shu
    Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
  • F. Zhao
    IHEP, Beijing, People's Republic of China
  
  An S band SLED-type pulse compressor has been manufactured by IHEP to challenge the 100 MW maximum input power, which means the peak power around the coupling irises is about 500 MW at the phase reversal time. In order to deal with the breakdown problem, the dual side-wall coupling irises model was used. To further improve the reliability at very high power, RF phase modulation (PM) with flat-top output is considered. By using the CST Microwave Studio (MWS) transient solver, a new method was developed to simulate the time response of the pulse compressor. In addition, the theoretical and experimental results of the PM theory are also presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN011  
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WEPMN014 A C-band Deflecting Cavity Design for High-precision Bunch Length Measurement cavity, simulation, electron, electromagnetic-fields 2948
 
  • J. Jiang, H.B. Chen, J. Shi, P. Wang
    TUB, Beijing, People's Republic of China
  
  Funding: NSFC 11375098 and 11327902
A standing wave RF deflecting structure has been designed as a tool for high-precision bunch length measurement. This 3-cell deflecting cavity is designed to operate at a frequency of 5.712GHz. In this paper, the RF design and thermal analysis of the deflecting cavity are introduced. We study the electromagnetic field distribution inside the cavity. The coupler design is also discussed. And the beam dynamics simulation is shown. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN014  
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WEPMN018 Measurement of Cell-Cell Coupling Coefficient in Photocathode RF Gun gun, simulation, laser, cathode 2963
 
  • P. Wang, H.B. Chen, Q. Gao, J. Shi, L. Zhang
    TUB, Beijing, People's Republic of China
  
  A photocathode RF gun is under cold rest in Tsinghua University. We measured the single cavity frequency and the cell-cell coupling coefficient by the detuning method with high accuracy. We use a simplified model to illustrate the whole process of the measurement. The data obtained in the cold test seem to accord with that from the model very well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN018  
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WEPMN045 IOT Use as a Power Source for a Linear Accelerating Structure cavity, klystron, proton, simulation 3027
 
  • E.A. Savin, S.V. Matsievskiy, N.P. Sobenin, I.D. Sokolov
    MEPhI, Moscow, Russia
  • A.A. Zavadtsev
    Nano, Moscow, Russia
  
  Nowadays the interest of using compact and high efficiency power sources called Inductive Output Tubes (IOT) [1] for feeding accelerating structures with the required pulsed power around 1MW is increasing. In this article results of the beam dynamics and geometry calculations for the L-band IOT S-band IOT and accelerator-generator hybrid module are presented. Different concepts of the cavity have been proposed, but the most efficient has been chosen. The layout of the generator cell with biperiodic bunсher cells has been investigated. The hybrid structure composed from the generator cell and the compact SW accelerating section is proposed.
IOT, linear accelerator, power supply, klystrons 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN045  
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WEPMN049 Calibration of the Acceleration Voltage of Six Normal Conducting Cavities at ALBA cavity, synchrotron, operation, pick-up 3036
 
  • B. Bravo, U. Iriso, J. Marcos, J.R. Ocampo, F. Pérez, A. Salom, P. Solans
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  
  ALBA is a 3Gev synchrotron light source located in Barcelona and operating with users since May 2012. The ALBA storage ring uses six room temperature cavities; each one fed by two 80kW IOTs amplifiers at 499.654 MHz. An accurate calibration of the RF voltage is required for the right adjustment of the beam synchronous phase. In addition, if the ring accommodates several RF cavities, these may not be optimally phased with respect to each other, complicating the calculation of the total RF voltage. In this paper, the steps to calibrate the accelerating voltage of the SR cavities will be presented and different methodologies to cross-check these calibrations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN049  
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WEPMN058 Transverse Impedance Measurements and DC Breakdown Tests on the First Stripline Kicker Prototype for the CLIC Damping Rings impedance, simulation, kicker, extraction 3058
 
  • C. Belver-Aguilar, A. Faus-Golfe
    IFIC, Valencia, Spain
  • M.J. Barnes, H.A. Day
    CERN, Geneva, Switzerland
  • A. Faus-Golfe
    LAL, Orsay, France
  • F. Toral
    CIEMAT, Madrid, Spain
  
  A first stripline kicker prototype for beam extraction from the CLIC Damping Rings (DRs) has been designed at IFIC and CIEMAT, with excellent field homogeneity, good power transmission and low beam coupling impedance. The prototype has been built by the company Trinos Va\-cuum Projects, and laboratory tests and measurements have been carried out at CERN to characterize, without beam, the electromagnetic response of the striplines. In this paper, we present the measurements of the transverse beam coupling impedance, using the coaxial wire method, and a comparison with simulations. Furthermore, results of DC breakdown tests, using High Vol\-ta\-ge (HV) power supplies, are also reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN058  
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WEPHA023 Ferrite-tuner Development for 80 MHz Single-Cell RF-Cavity Using Orthogonally Biased Garnets cavity, simulation, resonance, operation 3159
 
  • C. Vollinger, F. Caspers
    CERN, Geneva, Switzerland
  
  In the frame of the LHC Injector Upgrade program involving the existing 80 MHz cavities in the CERN PS accelerator, an orthogonally biased ferrite tuner is foreseen to complement the current motor-driven piston tuner. This ferrite tuner shall provide the possibility of a fast frequency shift of about 200 kHz on the fundamental mode, to allow a fast switching between proton and ion frequencies. In order to avoid water cooling and related issues, the challenge was to bring magnetic losses in the tuner to a minimum such that a forced air cooling scheme will be sufficient. The tuner was first designed with simulation tools, a prototype was built and low-power RF testing was performed on the tuner-cavity combination to evaluate tuning range, bandwidth, and stability. These tests were carried out on a single-cell copper RF cavity mock-up with a resonance frequency of 88 MHz, where the ferrite tuner is connected via a tuning loop and the perpendicular magnetic bias for ferrite tuner is provided by a DC bias supply. Simulations and test data will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA023  
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WEPHA053 Surface Resistance RF Measurements of Materials Used for Accelerator Vacuum Chambers cavity, factory, resonance, network 3235
 
  • P. Goudket, L. Gurran, O.B. Malyshev, M.D. Roper, R. Valizadeh, S. Wilde
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt, L. Gurran
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • P. Goudket, O.B. Malyshev, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S. Wilde
    Loughborough University, Loughborough, Leicestershire, United Kingdom
  
  The RF surface resistance of accelerator vacuum chamber walls can have a significant impact on the beam quality. There is a need to know how the use of a new material, surface coating or surface treatment can affect the RF surface resistance. ASTeC and Lancaster University have designed and built two test cavities where one face can be replaced with a sample in the form of a flat plate. The measurements are performed with a network analyser at the resonant frequency of approximately 7.8 GHz.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA053  
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WEPHA054 Commissioning of the Transverse Deflecting Cavity on VELA at Daresbury Laboratory cavity, electron, klystron, vacuum 3239
 
  • A.E. Wheelhouse, R.K. Buckley, S.R. Buckley, L.S. Cowie, P. Goudket, L. Ma, J.W. McKenzie, A.J. Moss
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt, M. Jenkins
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  
  A 9-cell S-band transverse deflecting copper cavity (TDC) has been designed and built to provide a 5 MV transverse kick in order to perform longitudinal profile measurements of the electron bunch on the Versatile Electron Linear Accelerator (VELA) at Daresbury Laboratory. The cavity has been manufactured by industry and has been field flatness tuned using a beadpull system. The cavity has then been installed on to the VELA facility and commissioned for operation with the electron beam. This paper discusses the tuning and the RF conditioning of the cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA054  
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WEPTY046 Progress on the MICE 201 MHz Cavities at LBNL cavity, Windows, simulation, network 3378
 
  • T.H. Luo, A.J. DeMello, A.R. Lambert, D. Li, S. Prestemon, S.P. Virostek
    LBNL, Berkeley, California, USA
  
  The international Muon Ionization Cooling Experiment aims to demonstrate the transverse cooling of amuon beam by ionization in energy absorbers. The final MICE cooling channel configuration has two RF modules, each housing a 201 MHz RF cavity used to compensate the longitudinal energy loss in the absorbers. The LBNL team has designed and fabricated all MICE RF cavities. The cavities will be post-processed and RF measured before being installed in the RF modules. We present the recent progress on this work, including the low level RF measurement on cavity body and Be windows, the electro-polishing (EP) on the cavity surface, the numerical simulation on cavity Be window detuning, and the ongoing mechanical designing work of cavity components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY046  
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WEPTY055 Installation and Commissioning of the MICE RF Module Prototype cavity, vacuum, Windows, operation 3395
 
  • Y. Torun, P.G. Lane
    Illinois Institute of Technology, Chicago, Illlinois, USA
  • T.G. Anderson, D.L. Bowring, M. Chung, J.H. Gaynier, M.A. Leonova, A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz
    Fermilab, Batavia, Illinois, USA
  • A.J. DeMello, D. Li, S.P. Virostek
    LBNL, Berkeley, California, USA
  • L. Somaschini
    INFN-Pisa, Pisa, Italy
  
  Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program.
A special vacuum vessel prototype was built to house the first production 201 MHz RF cavity for the International Muon Ionization Cooling Experiment (MICE). The resulting prototype RF module has been assembled, instrumented, installed and commissioned at Fermilab's MuCool Test Area and the effort has provided valuable experience for the design of modules that will be used in the cooling channel for the experiment. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY055  
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WEPTY082 High Gradient Testing of the Five-cell Superconducting RF Module with a PBG Coupler Cell cavity, HOM, linac, SRF 3471
 
  • S. Arsenyev, W.B. Haynes, D.Y. Shchegolkov, E.I. Simakov, T. Tajima
    LANL, Los Alamos, New Mexico, USA
  • C.H. Boulware, T.L. Grimm, A. Rogacki
    Niowave, Inc., Lansing, Michigan, USA
  
  We report results of high-gradient testing of the first 5- cell superconducting radio frequency (SRF) module with a photonic band gap cell (PBG). Higher order mode (HOM) damping is vital for preserving the quality of high-current electron beams in novel SRF accelerators. Because HOMs are not confined by the PBG array, they can be effectively damped in order to raise the current threshold for beam instabilities. The PBG design increases the real-estate gradient of the linac because both HOM damping and the fundamental power coupling can be done through the PBG cell instead of via the beam pipe at the ends of the cavity. A superconducting multi-cell cavity with a PBG damping cell is therefore an attractive option for high-current linacs. The first-ever SRF multi-cell cavity incorporating a PBG cell was designed a LANL and built at Niowave Inc. The cavity was tuned to a desired gradient profile and underwent surface treatment at Niowave. A vertical test (VTS) was then performed at LANL, demonstrating an abnormally low cavity quality factor in the accelerating mode of 1.6*106. Future tests are proposed to determine the source of the losses and resolve the problem.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY082  
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WEPWI004 FPC and Hi-Pass Filter HOM Coupler Design for the RF Dipole Crab Cavity for the LHC HiLumi Upgrade HOM, cavity, dipole, damping 3492
 
  • Z. Li
    SLAC, Menlo Park, California, USA
  • S.U. De Silva, J.R. Delayen, R.G. Olave, H. Park
    ODU, Norfolk, Virginia, USA
  
  Funding: Work partially supported by the US DOE through the US LHC Accelerator Research Program (LARP), and by US DOE under contract number DE-AC02-76SF00515.
A 400-MHz compact RF dipole (RFD) crab cavity design was jointly developed by Old Dominion University and SLAC under the support of US LARP program for the LHC HiLumi upgrade. The RFD cavity design is consisted of a rounded-square tank and two ridged deflecting poles, operating with a TE11-like dipole mode, which is the lowest mode of the cavity. A prototype RFD cavity is being manufactured and will be tested on the SPS beam line at CERN. The coaxial fundamental Power Coupler (FPC) of the prototype cavity was re-optimized to minimizing the power heating on the coupler internal antenna. A hi-pass filter HOM damping coupler was developed to achieve the required wakefield damping while maintaining a compact size to fit into the beam line space. In this paper, we will discuss the details of the RF optimization and tolerance analyses of the FPC and HOM couplers. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI004  
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WEPWI006 Dither Coils for the SuperKEKB Fast Collision Feedback System vacuum, feedback, collider, multipole 3500
 
  • U. Wienands, S.D. Anderson, S.M. Gierman, M. Kosovsky, C.M. Spencer, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • Y. Funakoshi, M. Masuzawa, T. Oki
    KEK, Ibaraki, Japan
  
  Funding: Work supported in part by US DOE and in part by the US-Japan collaboration agreement.
The collision feedback system for the SuperKEKB electron-positron collider at KEK will employ a dither feedback with a roughly 100 Hz excitation frequency to generate a signal proportional to the offset of the two beams. The excitation will be provided by a local bump across the interaction point (IP) that is generated by a set of eight air-core solid-wire magnet coil assemblies, each of which provides a horizontal and/or vertical deflection of the beam, to be installed around the vacuum system of the SuperKEKB Low Energy Ring. The design of the coils was challenging as large antechambers had to be accommodated and a 0.1% relative field uniformity across a good-field region of ±1 cm was aimed for, while keeping reasonable dimensions of the coils. This led to non-symmetric, non-flat designs of the coils. The paper describes the magnetic design and the method used to calculate the magnetic field of the coils, the mechanical design and the field measurement results. Tracking in the lattice model has indicated acceptable performance. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI006  
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WEPWI029 Cavity Design, Fabrication and Test Performance of 750 MHz, 4-Rod Separators for CEBAF 4-Hall Beam Delivery System cavity, simulation, hardware, target 3548
 
  • H. Wang, G. Cheng, L. Turlington, M.J. Wissmann
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A short version of the original CEBAF normal conducting 4-rod separator cavity has been developed into a 750MHz one * since the concept of simultaneous 4-hall operation for CEBAF is introduced **. This work has been advanced further based on the EM design optimization, bench measurement and by conducting RF-thermal coupled simulation using CST and ANSYS to confirm the cavity tuning and thermal performance. The cavity fabrication used matured technology like copper plating and machining. The cavity flanges, couplers, tuners and cooling channels adopted consistent/compatible hardware with the existing 500MHz cavities. The electromagnetic and thermal design simulations have greatly reduced the prototyping and bench tuning time of the first prototype. Four production cavities have reached a typical 1.94MV kick voltage or 3.0kW wall loss on each cavity after a minor multipactoring or no processing, 7.5% overhead power than the design specification.
* R. Kazimi et al., IPAC2013, Shanghai, China, pp 2896-2898.
** R. Kazimi, IPAC2013, Shanghai, China, pp 3502-3504.
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI029  
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WEPWI046 Demonstration of Coaxial Coupling Scheme at 26 MV/m for 1.3 GHz TESLA-type SRF Cavities cavity, niobium, SRF, acceleration 3594
 
  • Y. Xie, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • T.N. Khabiboulline, A. Lunin, V. Poloubotko, A.M. Rowe, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • J. Rathke
    AES, Medford, New York, USA
  
  Funding: Work sponsored by DOE SBIR Grant DE-SC0002479.
We will report the first successful rf test of a detachable coaxial coupler by Euclid Techlabs and Fermilab SRF development department. The coaxial coupling method has vast advantages compared with ordinary welded-on couplers. It totally eliminates coupler kicks and it is detachable and easy to clean. We reached 26 MV/m (no hard quench limit) with a quarter-wave detachable coaxial coupler. This is also a demonstration of the highest field gradient ever reached with a superconducting joint. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI046  
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WEPWI054 Design and Test of the RHIC CMD10 Abort Kicker kicker, impedance, vacuum, network 3612
 
  • H. Hahn, M. Blaskiewicz, K.A. Drees, W. Fischer, W. Meng, J.-L. Mi, C. Montag, C. Pai, J. Sandberg, N. Tsoupas, J.E. Tuozzolo, W. 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.
Planned and unplanned thyratron pre-fire triggered beam dumps have been observed in the yellow ring that were associated with quenches of the superconducting main ring magnets as the proton intensities increased in the FY1013 run. The increasing vacuum level indicated beam induced kicker ferrite heating causing lower magnetic kick field at a nominal pulse current. In anticipation of higher current and shorter bunches in FY2015 an accelerator improvement program was initiated to reduce the longitudinal coupling impedance with changes to the eddy-current strip geometry using Opera simulations and to change the CMD5005 to CMD10 ferrite. Results of the standard impedance measurements and of pulse current in heating tests to 170 °C are reported. All 10 dump kickers are being modified and are encapsulated with a cooling system for installation in the rings. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI054  
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WEPWI059 Higher Order Mode Filter Design for Double Quarter Wave Crab Cavity for the LHC High Luminosity Upgrade HOM, cavity, impedance, luminosity 3627
 
  • B. P. Xiao, S.A. Belomestnykh, I. Ben-Zvi, J. Skaritka, S. Verdú-Andrés, Q. Wu
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • G. Burt, B.D.S. Hall
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • R. Calaga, O. Capatina
    CERN, Geneva, Switzerland
  • T.J. Jones
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Work partly supported by US LARP, by US DOE under contract No. DE-AC02-05CH11231 and through BSA under contract No. DE-AC02-98CH10886. Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404.
A double quarter wave crab cavity (DQWCC) was designed for the Large Hadron Collider (LHC) luminosity upgrade. A compact Higher Order Mode (HOM) filter with wide stop band at the deflecting mode is developed for this cavity. Multi-physics finite element simulation results are presented. The integration of this design to the cavity cryomodule is described. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI059  
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THPF014 325 MHz High Power RF Coupler for the CH-Cavities of the FAIR p-LINAC cavity, linac, proton, simulation 3712
 
  • F. Maimone, R. M. Brodhage, M. Kaiser, W. Vinzenz, M. Vossberg
    GSI, Darmstadt, Germany
  
  In order to supply the input RF power to the Cross-bar H-mode (CH) cavities of the p-LINAC for FAIR an inductive RF coupler has been studied. The designed RF coupler, and its water cooled inductive loop, has to withstand up to a 3 MW pulsed power (at 325 MHz). At GSI a prototype has been manufactured and tests were performed. The prototype of the designed high power RF coupler is presented together with the results of the coupling measurements at the CH-prototype cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF014  
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THPF069 The Early Results of the Vertical Test for β=0.12 HWR at RISP cavity, vacuum, cryogenics, niobium 3839
 
  • G.-T. Park, H.J. Cha, H.C. Jung, H. Kim, W.K. Kim, Y.J.K. Kim
    IBS, Daejeon, Republic of Korea
  
  At RISP, we are planning to perform the vertical test of the β=0.12 half wave resonator. We report our progress on the preparation of the test including the cryogenic system, the RF system, the control and data acquisition system, and the radiation shields. We had the first few occaaisions of the cool down and various measurements at a low gradient. Out preliminary result on the Q0-Eacc excitation curve will be given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF069  
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