Keyword: resonance
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MOPRO081 Resonance Frequency Feedback System for a Precise Magnet Alignment using Multi-vibrating Wires feedback, quadrupole, alignment, emittance 277
 
  • K. Fukami, N. Azumi, T. Fujita, T. Honiden, H. Kimura, T. Nakanishi, Y. Okayasu, C. Zhang
    JASRI/SPring-8, Hyogo-ken, Japan
  • K. Kajimoto, T. Watanabe
    SES, Hyogo-pref., Japan
  • S. Matsui
    RIKEN/SPring-8, Hyogo, Japan
  
  An ultimate storage ring (USR) is being designed at synchrotron radiation facilities in the world. USR can generate theoretically minimum synchrotron radiation because emittance of the USR is less than diffraction limit of the radiation. The USR requires high alignment precision of micro-meter order. A vibrating wire method (VWM) has widely been used for such a high precision alignment. An error field of multi-pole magnet is estimated by detecting a vibration of a single wire excited with AC current. The wire position, where no vibration is excited, is defined as the magnetic center. The applied frequency is kept on a resonant frequency, which may drift due to temperature change etc. during the measurement. To trace the resonant frequency at all times, we developed a frequency feedback system. It is necessary to trace the resonance, even when the wire is set in the vicinity of the magnetic center where the magnetic field is nearly zero. Here we propose to install one or two additional wires parallel to the original wire. The additional wires off the center can detect the vibration frequency with enough S/N ratio. We discuss the effectiveness of it for quick and reliable alignment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO081  
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MOPME011 Matrix Integration of ODEs for Spin-orbit Dynamics Simulation simulation, lattice, operation, quadrupole 400
 
  • A.N. Ivanov, Y. Senichev
    FZJ, Jülich, Germany
  
  MODE (Matrix integration of Ordinary Differential Equations) is a software package that provides nonlinear matrix maps building for spin-orbit beam dynamics simulation. In this article we briefly describe the developed integrated development environment features and present computational comparison with other simulation tools. MODE mathematical model is based on Newton-Lorentz and T-BMT equations that are expanded to Taylor series up to the necessary order of nonlinearity. The numerical algorithm is based on matrix presentation of Lie propagator. Spin-orbit simulation results of MODE are compared with results of COSY Infinity and OptiM. MODE provides a flexible graphic user interface, code auto complete technology and visual designer for accelerators. There is also a possibility to generate codes in different programming languages and parallelization techniques.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME011  
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MOPRI034 Development of temporal response measurement system for transmission-type spin-polarized photocathodes electron, cavity, laser, linear-collider 670
 
  • T. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • M. Adachi
    KEK, Ibaraki, Japan
  • X.G. Jin
    Institute for Advanced Research, Nagoya, Japan
  • M. Katoh, T. Konomi
    UVSOR, Okazaki, Japan
  • Y. Okano
    IMS, Okazaki, Japan
  
  Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved*,**. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode***. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results.
* T. Nakanishi, The XXI International LINAC Conference(1998)
** Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004
*** Xiuguang Jin, Applied Physics Express 6 (2013) 015801 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034  
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MOPRI058 Metal Plasmonic Nanostructures Functionalized by Atomic Layer Deposition of MgO for Photocathode Applications electron, cathode, vacuum, emittance 739
 
  • S.V. Baryshev, S.P. Antipov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • M.R. Savina, A.V. Zinovev
    ANL, Argonne, Illinois, USA
  • E. Thimsen
    University of Minnesota, Minneapolis, USA
  
  Funding: Euclid TechLabs LLC acknowledges support from the DOE SBIR program, grant No. DE-SC0009572.
To create high current, long lasting electron sources capable of providing sub-ps bunches, new photocathode concepts are sought. Most recently, plasmonic nanostructured metal surfaces or flat metal surfaces activated by an ultrathin MgO are under great attention. We report on a photocathode design combining these two approaches. It consists of plasmonic Ag nanoparticles (NPs) functionalized by 3 MgO monolayers (MLs). Ag NPs were synthesized by an aerosol method and MgO was grown by atomic layer deposition (ALD). The NPs geometry was tuned to obtain broadband >50% absorption in the entire blue range as evidenced by UV-vis. spectroscopy. The WF of 3 MgO MLs/Ag NPs multilayer was reduced by 1 eV compared to bare NPs, from 5 to 4 eV, as evidenced by UPS and Kelvin probe. Reduction by 1 eV is maximal for this pair of materials, and agrees well with experimental and theoretical findings. While the effect on WF is indeed significant, a special handling protocol for Ag before depositing MgO is a must. It would preserve a clean Ag surface with a WF of nearly 4 eV to achieve 3 eV upon ALD of MgO. This and other issues are under study to promote photocathode applications. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI058  
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MOPRI091 Resonant Slow Extraction in Synchrotrons by Using Anti-symmetric Sextupole Fields sextupole, extraction, simulation, synchrotron 827
 
  • Y. Zou, J.Y. Tang
    IHEP, Beijing, People's Republic of China
  
  This paper proposes a novel method for non-resonant slow extraction by using special anti-symmetric sextupole field in synchrotrons. The method has the potential in applications asking for stable slow extraction and in the halo collimation of very large machine such as LHC. Our studies show that the slow extraction by using anti-symmetric sextupole field has some advantages compared to the normal sextupole field which is the normal extraction method. One of them is that it can work at almost arbitrary tune, so that it can avoid the problem of the intensity variation caused by the ripples of magnet supplies. Studies by Hamiltonian theory and simulations which meet well show that the stable region only depends on the anti-symmetric sextupole field strength and the particles outside will be driven out in two directions which are similar to the second-order resonant extraction but with spiral steps as in the third-order resonance extraction. The beam can be extracted with a very stable intensity by gradually increasing the field strength. The multi-particle simulations by a self-made program have been carried out with a proton lattice designed for proton therapy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI091  
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MOPRI094 Proposal for a Slow Extraction System for a Biomedical Research Facility at CERN based on LEIR extraction, emittance, sextupole, quadrupole 833
 
  • A. Garonna, D. Abler, C. Carli
    CERN, Geneva, Switzerland
  
  Funding: This work was partly funded by the Marie Curie Initial Training Network Fellowship of the European Community’s Seventh Framework Programme under contract number PITN-GA-2008-215840-PARTNER.
A proposal has been made to accelerate ion beams ranging from hydrogen to neon with magnetic rigidities up to 6.7 Tm for biomedical experiments at CERN using the Low Energy Ion Ring (LEIR), in parallel to its continued operation for LHC and for SPS fixed target physics experiments. The feasibility of a new slow extraction system for LEIR based on the third integer resonance was studied with two possible resonance driving mechanisms: quadrupole-driven extraction and RF-knockout extraction. The extraction of fully stripped carbon ions (20-440 MeV/u kinetic energies) has been studied in detail. The requirement to keep the present performance of the machine for physics experiments imposes tight space constraints for the upgrade. The extraction scheme and the hardware requirements are described in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI094  
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TUPRO006 Strong-strong Beam-beam Simulation for the LHC Upgrade emittance, simulation, cavity, luminosity 1006
 
  • J. Qiang, S. Paret
    LBNL, Berkeley, California, USA
  • G. Arduini, T. Pieloni
    CERN, Geneva, Switzerland
  • J. Barranco García
    EPFL, Lausanne, Switzerland
  
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using computing resources at the NERSC.
The LHC upgrade will significantly improve the performance of the current LHC operation with higher collision energy and luminosity. In the paper, we report on the progress in the strong-strong beam-beam simulation of the HL-LHC upgrade with crab cavity compensation. We will present the study of the effects of accelerator tune working points, dipole noise, and crab cavity noise on colliding beam emittance growth. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO006  
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TUPRO039 Optimizing Polarization with an Improved Integer Resonance Correction Scheme at ELSA polarization, electron, quadrupole, closed-orbit 1108
 
  • J.F. Schmidt, O. Boldt, F. Frommberger, W. Hillert, J.-P. Thiry
    ELSA, Bonn, Germany
  
  Funding: DFG
The Electron Stretcher Facility ELSA of Bonn University provides a polarized electron beam of up to 3.2 GeV. In the stretcher ring various depolarizing resonances are crossed during the fast energy ramp of 6 GeV/s. The high polarization degree of up to 70% can only be conserved by taking several appropriate countermeasures. Concerning integer resonances, additional harmonic horizontal fields are applied by orbit correction magnets around the ring to compensate the resonance driving fields. The correction field has to be adjusted by empirical optimization of polarization. Recent developments enhance this optimization process, especially at high energies: A new magnet system allows for higher correction amplitudes and shorter rising times. Furthermore, a modified correction scheme was implemented. It takes into account the additional fields of the quadrupole magnets, arising from the orbit response of the correction magnets. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO039  
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TUPRO040 High Bandwidth Closed Orbit Control for a Fast Ramping Electron Accelerator closed-orbit, acceleration, electron, polarization 1111
 
  • J.-P. Thiry, A. Dieckmann, F. Frommberger, W. Hillert, J.F. Schmidt
    ELSA, Bonn, Germany
  
  ELSA is a fast ramping stretcher ring capable of acceleration and storage of polarized electrons with energies up to 3.2 GeV. To preserve the initial degree of polarization, the acceleration is performed by a fast energy ramp with a maximum ramping speed of 6 GeV/s. During acceleration especially the vertical orbit needs to be continuously corrected so that the vertical rms deviation does not exceed 50 μm at any time. In order to compensate the so called integer resonances, which occur at certain energies, the orbit correction system further needs to provide additional, empirically determined, harmonic field distributions. A successful application of these combined correction measures requires a considerably high bandwidth of up to some 100 Hz. In our contribution we will have a closer look at the performance and the acquired bandwidth of the correction system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO040  
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TUPRO052 Study a ‘Sum’ Linear Coupling Resonance for J-PARC Main Ring: Observations and Simulations operation, injection, coupling, emittance 1147
 
  • A.Y. Molodozhentsev, S. Igarashi
    KEK, Ibaraki, Japan
  • Y. Sato, J. Takano
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  J-PARC Main Ring should deliver a high-power proton beam to neutrino experiments with limited particle losses. To meet this requirement low-order machine resonances have to be compensated. The linear coupling resonance Qx+Qy=43 has been identified as the potential source for significant particle losses at the collimator. The resonance compensation scheme has been studied experimentally by using a low intensity beam. To understand this process the simulations have been performed by using the PTC-ORBIT code. The Main Ring model has been developed to reproduce the machine operation including the initial stage of the acceleration. The 6D beam model has been defined to represent the ‘pencil’ beam used for this study. In frame of this report the single and multi particle dynamics will be discussed to understand the results of measurements, performed during RUN44 (November 2012). The results of the long-term tracking for this case will be presented. The obtained results can be used to benchmark the computer modeling the ‘sum’ linear coupling resonance with the experimental results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO052  
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TUPRO059 Beam Energy Measurements using Resonant Spin Depolarization at ALBA polarization, beam-losses, feedback, synchrotron 1168
 
  • Z. Martí, U. Iriso, F. Pérez
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
  
  Energy measurements with precision down to 10-5 are inferred from the lifetime evolution when the beam is depolarized using AC kicks with the Transverse Fast Feedback system. Lifetime measurements are carried out using the DCCT, the BPM sum signals, pin-diode BLMs, and a scintillator based Beam Loss Detector. Results obtained with this instrumentation are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO059  
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TUPRO077 AGS Snake Stories solenoid, injection, kicker, extraction 1220
 
  • F. Méot, Y. Dutheil, R.C. Gupta, H. Huang, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • J. Takano
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This contribution re-visits fields, particle motion, and spin precession in the AGS helical polarization snakes. The work was undertaken in preparation of orbit and spin modeling for future polarized proton and helion runs at RHIC. The investigations include re-computation of 3-D OPERA field maps of the helical snakes and particle and spin tracking. There is a series of sub-products of this study, amongst others, the appropriate settings of the AGS cold snake when changing its strength, cold snake settings for polarized helion programs, non-linear coupling in the AGS, the transport of the stable polarization axis from the AGS to RHIC injection kickers, and in addition, a series of high accuracy 3-D field maps have been produced, in view of long-term tracking in the AGS for beam and polarization transmission studies. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO077  
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TUPRO107 Prediction of the Field Distribution in CERN-PS Magnets simulation, synchrotron, vacuum, injection 1298
 
  • D. Schoerling
    CERN, Geneva, Switzerland
  
  The CERN Proton Synchrotron (PS) has a circumference of 628 m and operates at an energy of up to 26 GeV. It uses one hundred combined function magnets, with pole shapes designed to create a dipolar and a quadrupolar field component. Each magnet is equipped with a main current circuit and five auxiliary current-circuits, which allows controlling the linear and non-linear magnetic fields. These magnets were installed in the 1950s, and part of the compensating circuits have been added or modified since then, resulting in the fact that detailed measurements of the field distribution in each individual magnet as a function of the six currents are not available. This study is performed to estimate, through deterministic and stochastic calculations, the expected mean value and standard deviation of the field harmonics of the installed magnets as input for beam dynamics simulations. The relevant results can be used to design correction schemes to minimise beam losses in the PS and to enable the acceleration of higher brightness beams required to reach the foreseen Large Hadron Collider (LHC) luminosity targets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO107  
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TUPME029 Identification of High-frequency Resonant Impedance in the CERN SPS impedance, simulation, vacuum, damping 1416
 
  • E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, J.V. Campelo, F. Caspers, J. F. Esteban Müller, A. Lasheen, B. Salvant, H. Timko
    CERN, Geneva, Switzerland
  
  The spectrum of long bunches injected into the ring with RF switched off has been used in the SPS in the past to probe the longitudinal coupling impedance. After a large campaign of shielding of 800 inter-magnet vacuum ports in 1999 - 2001, the microwave instability threshold was significantly increased and the high-frequency spectrum of the beam became practically flat, apart from a prominent peak at around 1.4 GHz. As corresponding high-frequency impedance could potentially lead to microwave instability of high intensity bunches observed now at high energies in the SPS, a search of the source of this impedance was launched. Using a combination of impedance simulations and measurements, vacuum flanges that are present in a large quantity in the machine have been identified as a main source of impedance at this frequency. Particle simulations based on the SPS impedance model, which includes this previously unknown impedance, are able to reproduce the characteristics of the bunch spectrum and amplitude growth rates and hence, confirm that the impedance of the vacuum flanges is responsible for the observed spectral peak.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME029  
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TUPRI009 Study of Resonance Crossing in Non-scaling FFAGs using the S-POD Linear Paul Trap ion, dipole, experiment, acceleration 1571
 
  • D.J. Kelliher, S. Machida, C.R. Prior, S.L. Sheehy
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • K. Fukushima, K. Ito, K. Moriya, H. Okamoto, T. Okano
    HU/AdSM, Higashi-Hiroshima, Japan
  
  Experiments on EMMA have shown that with rapid acceleration (~10 turns) a linear non-scaling FFAG can accelerate through several integer tunes without detrimental effects on the beam [1]. Proton and ion applications such as hadron therapy will necessarily have a slower acceleration rate, so their feasibility depends on how harmful resonance crossing is in this regime. A simple and useful tool to answer such fundamental questions is the S-POD linear Paul trap at Hiroshima University, which can be set up to simulate the dynamics of a beam in an FFAG. We report here results of experiments to explore different resonance crossing speeds, quantify beam loss and study nonlinear effects. We also discuss the implications of these experimental results in terms of limits on acceptable acceleration rates and alignment errors.
[1] S.Machida et al, Nature Physics, N8, 243-257 (2012) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI009  
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TUPRI022 Beam-Beam Studies in LHC- Beam Loss and Bunch Shortening emittance, simulation, synchrotron, luminosity 1603
 
  • K. Ohmi
    KEK, Ibaraki, Japan
  
  In Hadron colliders, luminosity degrade various mechanism. Beam-beam related emittance growth is caused by resonances induced by crossing angle. Tune spread due to chromaticity enhances the resonances effect. A bunch shortening phenomenon related to beam-beam interaction has been observed in LHC. The bunch length has an anti-correlation with transverse emittance. This phenomenon has been studied using a weak-strong beam-beam simulation (BBWS code).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI022  
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TUPRI023 Simulation of Debunching for Slow Extraction in J-PARC MR cavity, beam-loading, simulation, impedance 1606
 
  • M. Yamamoto, M. Nomura, T. Shimada, F. Tamura
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • E. Ezura, K. Hara, K. Hasegawa, C. Ohmori, A. Takagi, K. Takata, M. Toda, M. Yoshii
    KEK, Ibaraki, Japan
  • A. Schnase
    GSI, Darmstadt, Germany
  
  The J-PARC MR delivers a proton beam for nuclear physics experiments with slow extraction. The beam is debunched at flat top to obtain a coasting beam by turning off the rf voltage. The controlled emittance blow-up before the flat top has been investigated to mitigate the microwave instability. Beam loading effect can disturb the uniformity of the debunching at the flat top. We describe the results of the particle tracking simulation whole acceleration cycle including the controlled emittance blow-up and the beam loading effect.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI023  
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TUPRI029 The CERN PS Booster Space Charge Simulations with a Realistic Model for Alignment and Field Errors simulation, space-charge, lattice, alignment 1624
 
  • V. Forte, E. Benedetto, M. McAteer
    CERN, Geneva, Switzerland
  
  The CERN PS Booster is one of the machines of the LHC injector chain which will be upgraded within the LIU (LHC Injectors upgrade) project. The injection energy of the PSB will be increased to 160MeV in order to mitigate direct space charge effects, considered to be the main performance limitation, thus allowing to double the brightness for the LHC beams. In order to better predict the gain to be expected, space charge simulations are being carried out. Efforts to establish a realistic modeling of field and alignment errors aim at extending the basic model of the machine towards a more realistic one. Simulations of beam dynamics with strong direct space charge and realistic errors are presented and analysed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI029  
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TUPRI038 The Low Energy Particle Wakefield Radiation From the Open End of Internally Coated Metallic Tube radiation, wakefield, experiment, vacuum 1644
 
  • M. Ivanyan, A. Grigoryan, A. Sargsyan, A.V. Tsakanian
    CANDLE SRI, Yerevan, Armenia
  
  The radiation of the non-relativistic electron beam from the open end of the resistive circular waveguide is presented. The angular and spectral characteristics of the radiation are determined. The possibility of producing the focused guasi-monochromatic radiation is discussed. The principal scheme of the experiments for 5 and 20 MeV AREAL RF photogun linac is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI038  
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TUPRI054 FEM Analysis of Beam-coupling Impedance and RF Contacts Criticality on the LHC UA9 Piezo Goniometer impedance, simulation, experiment, coupling 1692
 
  • A. Danisi, R. Losito, A. Masi, A. Passarelli, B. Salvant, C. Zannini
    CERN, Geneva, Switzerland
  
  The UA9 piezo-goniometer has been designed to guarantee micro-radians-accuracy angular positioning of a silicon crystal for a crystal collimation experiment in the LHC, and to minimize the impact on the LHC beam-coupling impedance. This paper presents a Finite Element Method (FEM) study of the device, in both parking and operational positions, to evaluate its impact on the LHC impedance budget. The study has been a progressive simulation work, started from the simplification of the original detailed design, and aimed at highlighting the effect of single details (e.g. objects in confining chambers) on the longitudinal and transverse components of beam-coupling impedance. In addition, the shielding contribution of the RF gaskets has been carefully evaluated, with the objective to assess the consequences for operation in case of their failure. Sensitivity analyses to simulation parameters are also performed, in order to test the FEM model robustness. A final word is drawn on the overall device impedance criticality.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI054  
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WEPRO056 Development of an Optical Resonant Cavity for the LCS Experiment at cERL cavity, laser, photon, experiment 2072
 
  • T. Akagi, Y. Honda, A. Kosuge, J. Urakawa
    KEK, Ibaraki, Japan
  • R. Hajima, M. Mori, R. Nagai, T. Shizuma
    JAEA, Ibaraki-ken, Japan
  
  A nondestructive assay system of isotopes by quasi-monochromatic gamma-rays by laser Compton scattering (LCS) is under development. In order to demonstrate the accelerator and laser performance required for the gamma-ray source, an LCS experiment is planned at Compact ERL (cERL) at KEK. An optical resonant cavity is under construction for the LCS experiment. The new optical cavity is designed by combination of two bow-tie cavities to achieve fast optical polarization switching. The performance of the optical cavity is presented in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO056  
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WEPRO066 Study for Space Charge effect in tune space at J-PARC MR coupling, space-charge, quadrupole, simulation 2100
 
  • K. Ohmi, S. Igarashi
    KEK, Ibaraki, Japan
  • H. Harada
    JAEA, Ibaraki-ken, Japan
  • Y. Sato
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  Choice of tune operating point is serious for operation of high intensity proton machine. Space charge force induces tune spread and nonlinear resonance. Nonlinear resonances are also contained in accelerator lattice. We discuss optimization of operating point based on space charge simulation in J-PARC Main Ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO066  
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WEPRO070 Overcoming the Horizontal Depolarizing Resonance in the Brookhaven AGS polarization, emittance, timing, betatron 2112
 
  • H. Huang, L. Ahrens, M. Bai, M. Blaskiewicz, K.A. Brown, R. Connolly, Y. Dutheil, W. Fischer, C.J. Gardner, J.W. Glenn, T. Hayes, F. Méot, A. Poblaguev, V.H. Ranjbar, T. Roser, V. Schoefer, K.S. Smith, S. Tepikian, N. Tsoupas, K. Yip, A. Zelenski, 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.
Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the AGS. The relatively weak but numerous horizontal resonances are the main source of polarization loss in the AGS. A pair of horizontal quads have been used to overcome these weak resonances. This technique needs very accurate jump timing. Fast roll-over magnet cycle has been used and it improves the polarization transmission efficiency near extraction when acceleration usually is slowing down. Emittance preservation is also important to mitigate polarization loss. Recent experimental results including jump quad timing and emittance preservation are presented in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO070  
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WEPRO071 Optics Setup in the AGS and AGS Booster for Polarized Helion Beam booster, proton, injection, polarization 2115
 
  • H. Huang, L. Ahrens, J.G. Alessi, M. Bai, E.N. Beebe, M. Blaskiewicz, K.A. Brown, Y. Dutheil, W. Fischer, C.J. Gardner, J.W. Glenn, T. Hayes, F. Méot, A. Poblaguev, V.H. Ranjbar, T. Roser, V. Schoefer, K.S. Smith, S. Tepikian, N. Tsoupas, K. Yip, A. Zelenski, K. Zeno
    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.
Future RHIC physics program calls for polarized He3 beam. The He3 beam from the new EBIS source has a relative low rigidity which requires delicate control of injection and RF setup in the Booster. The strong depolarization resonance strength in both AGS and AGS Booster requires careful consideration of beam energy range and optics setup. Recently, the He3 beam was accelerated to 11GeV/n in the AGS. The near term goal fo 3*1010 at RHIC requires several RF bunch merges in both AGS and the Booster. The beam test results are presented in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO071  
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WEPRO075 The Conceptual Design of the China White Neutron Source DTL, linac, neutron, rfq 2127
 
  • J.H. Li, X.C. Ruan, X. Wang
    CIAE, Beijing, People's Republic of China
  • J.H. Billen, K.R. Crandall
    TechSource, Los Alamos, New Mexico, USA
  • J. Stovall
    ESS, Lund, Sweden
  • J.Y. Tang
    IHEP, Beijing, People's Republic of China
  • L.M. Young
    AES, Medford, New York, USA
  
  Funding: Work supported by NSFC of (91126003)
In order to feed the nuclear data needs for design of the Chinese Accelerator Driven sub-critical System (CADS) and new generation nuclear energy systems, we plan to construct the China White Neutron Source (CWNS). The CWNS will be composed of a Proton Linac, an Accumulator Ring, a Target and Experimental Facilities. The linac is designed to deliver a proton beam having an average current of 1 mA at energy up to 300 MeV. The revolution frequency of the accumulator ring will be ~1.4 MHz. Two spallation targets are planned, with one for short pulsed modes and the other for micro-pulsed mode. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO075  
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WEPRO111 Fusion Based Neutron Sources for Security Applications: Neutron Techniques neutron, photon, scattering, target 2227
 
  • S.C.P. Albright, R. Seviour
    University of Huddersfield, Huddersfield, United Kingdom
  
  The current reliance on X-Rays and intelligence for national security is insufficient to combat the current risks of smuggling and terrorism seen on an international level. There are a range of neutron based security techniques which have the potential to dramatically improve national security. Neutron techniques can be broadly grouped into neutron in/neutron out and neutron in/photon out techniques. The use of accelerator based fusion devices will potentially enable to wide spread application of neutron security techniques due to the potential for much safer operation than that offered by fission or sealed tube sources. In this paper we discuss some of the neutron security techniques available and the advantages they present.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO111  
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WEPME077 Advanced Automatic Frequency Control System for a Dual Energy S-band RF Electron Linear Accelerator cavity, controls, electron, simulation 2459
 
  • S.S. Cha
    UST, Daejeon City, Republic of Korea
  • Y. Kim
    ISU, Pocatello, Idaho, USA
  • B.C. Lee, B.N. Lee, H.D. Park, K.B. Song
    KAERI, Daejon, Republic of Korea
  
  Funding: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the ministry of science ICT & future Planning (No. 2010-0026088), and MOTIE Korea (13-DU-EE-12).
The Radiation Instrumentation Research Division of Korea Atomic Energy Research Institute is developing a 2856 MHz dual energy [9, 6 MeV] s-band RF electron linear accelerator for security inspection. The s-band dual energy electron accelerator generates dual x-ray energy by irradiating a bunched electron beam from the cavity to a tungsten target. By detecting an x-ray, the cargo security inspection system can distinguish between organic and inorganic materials. Synchronization of the resonant frequency between the cavity and RF driver is an important factor for the stable operation of an accelerator. With a low RF driver power using the AFC, stable accelerator operations and a uniform output beam power can be obtained. This indicates that an accurate cargo inspection is possible. We used phase a frequency detector that can detect a wide frequency band and synchronize the resonance frequency between the RF driver and cavity. In this paper, we introduce a more advanced AFC system than a conventional AFC system. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME077  
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WEPRI053 Phase Method of Measuring Cavity Quality Factor cavity, simulation, coupling, data-analysis 2604
 
  • O.S. Melnychuk, R.V. Pilipenko, Y.M. Pischalnikov, W. Schappert, D.A. Sergatskov
    Fermilab, Batavia, Illinois, USA
  
  Novel method for measuring intrinsic quality factor of superconducting RF (SRF) cavities using both amplitude and phase information of forward, reflected, and transmitted cavity signal is discussed. Advantages of the method in comparison with traditional types of cavity quality factor measurements are highlighted. Computer simulations and evaluation of uncertainties for the measurements are described. Analysis of data collected at vertical test facility for SRF cavities at Fermilab is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI053  
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WEPRI064 New Insights into Heat Treatment of SRF Cavities in a Low-pressure Nitrogen Atmosphere cavity, niobium, SRF, vacuum 2634
 
  • D. Gonnella, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: United States Department of Energy
Recent results from Cornell and FNAL have shown that superconducting RF cavities given a heat treatment in a nitrogen atmosphere of a few mTorr display an increase in Q0 with increasing accelerating field, opposite to the medium field Q slope usually observed. Three cavities was prepared at Cornell using this method and subsequently tested after different amounts of material removal. Cavity performance and material properties were extracted for each cavity and correlated with material removal. This has given new insights into how material properties and the anti-Q slope depend on cavity preparation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI064  
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THOAA01 Beam Trip Analysis by Bunch-by-bunch BPM System in BEPCⅡ storage-ring, controls, positron, electron 2779
 
  • Q.Y. Deng, J.S. Cao, J. Yue
    IHEP, Beijing, People's Republic of China
  
  A new bunch-by-bunch beam position measurement prototype system has been designed and built to monitor and analysis beam trip in the BEPCⅡ(Beijing Electron-Positron ColliderⅡ) machine. The fast ADC and programmable FPGA can obtain the beam information bunch-by-bunch, so we can analyze base on both time domain and frequency domain. In this paper we will presentation the system architecture and discuss some beam trip analysis result, such as beam instability, tune drifting, RF breakdown, and so on.  
slides icon Slides THOAA01 [0.999 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOAA01  
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THPRO053 Ion Effects in the Cornell ERL High Intensity Photoinjector ion, radiation, simulation, electron 2989
 
  • S.J. Full, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  We present our first measurements of trapped ions in the Cornell energy recovery linac (ERL) photoinjector. During high intensity operation, ions become trapped inside of the electric potential generated by the electron beam and oscillate transversely with a characteristic frequency. At high beam currents, electron beam-ion interactions result in excessive radiation, primarily due to beam losses and bremsstrahlung. However, by shaking the beam at the trapped ion's oscillation frequency, we are able to drive a resonance that severely reduces or eliminates this radiation. This both confirms the viability of beam shaking as an ion mitigation strategy inside high intensity injectors, and allows us to measure the trapped ion oscillation frequencies indirectly. Experimental data for a beam energy of 5 MeV, a bunch repetition rate of 1.3 GHz, and beam currents up to 20 mA, as well as simulations to describe our data and the beam shaking principle are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO053  
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THPRO058 Study of the “Particle-in-Cell” Induced Noise on High Intensity Beams emittance, space-charge, simulation, synchrotron 3005
 
  • F. Kesting, G. Franchetti
    GSI, Darmstadt, Germany
  • U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Numerical noise in PIC codes produces artifacts which affects long term beam simulations needed for accelerator as the SIS100. A detailed study on the effect of numerical noise occurring in multi-particle tracking codes is presented. The influence of the granularity of particle distributions and the fineness of the meshes of Poisson solvers on the particle dynamics was studied. These results are used to discuss the effect of the PIC numerical noise in a long term space charge benchmarking study.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO058  
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THPRO061 New and Unifying Formalism for Study of Particle-Spin Dynamics Using Tools Distilled From Theory of Bundles polarization, HOM, lepton, framework 3014
 
  • K.A. Heinemann, J.A. Ellison
    UNM, Albuquerque, New Mexico, USA
  • D.P. Barber
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • D.P. Barber, M. Vogt
    DESY, Hamburg, Germany
  
  Funding: The work of JAE and KH was supported by DOE under DE-FG-99ER41104 and the work of DPB and MV was supported by DESY.
We summarize our recent work on spin motion in storage rings *. In fact we return to our study ** of spin motion in storage rings. We again focus on spin tunes, polarization fields etc. but in contrast to ** we base the description on one turn maps and refine and expand our toolset from that in * by using a rather modern method from Dynamical-Systems theory, developed in the 1980's by R. Zimmer and others based on bundles **, ***. With this we obtain new insights into invariant spin fields, invariant frame fields, spin tunes and spin-orbit resonances. At the same time we get a unified way to treat spin-1/2 and spin-1 particles. The bundle aspect is pointed out and we briefly mention the relation to Yang-Mills Theory as well.
* K.Heinemann, D.P.Barber, J.A.Ellison, M.Vogt. To be submitted.
** D.P.B., J.A.E., K.H., PRSTAB 7 (2004) 124002.
*** K.Heinemann, PhD Thesis, University of New Mexico, 2010 (available on the web). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO061  
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THPRO063 Spin Tune Parametric Resonance Investigation SRF, experiment, dipole, synchrotron 3020
 
  • Y. Senichev, A.N. Ivanov, A. Lehrach, R. Maier, D. Zyuzin
    FZJ, Jülich, Germany
  • S.N. Andrianov
    St. Petersburg State University, St. Petersburg, Russia
  
  The idea of resonant spin oscillation method was modernized and improved in Forschungszentrum Julich in the proposed experiment at the COSY ring. The resonant method is based on spin tune parameterization using transverse RF magnetic or/and electric field. The spin orientation smearing due to the finite spin coherence time (SCT) plays a crucial in the proposed experiment to search for the electric dipole moment. Our analysis is based on the T-BMT differential equations for spin together with shorten motion equations. Using well developed theory of Mathieu's differential equations we have got simplified analytic solution for prediction of spin behavior. In this paper we have numerically evaluated all effects having fundamental contributions from our point of view.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO063  
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THPRO068 Multipoles and Alignment Error Limits for the SESAME Storage Ring Magnets dynamic-aperture, multipole, dipole, sextupole 3035
 
  • M. Attal, E. Huttel
    SESAME, Allan, Jordan
  
  SESAME storage ring magnets are being constructed through the CESSAMag project in the frame of SESAME - CERN/EU collaboration. The impact of multipole and alignment errors of these magnets on machine performance have been investigated using different tracking codes. The tolerance of both systematic and random errors are defined. This article reports on the investigation results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO068  
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THPRO076 Frequency Maps Analysis of Tracking and Experimental Data for the SLS Storage Ring synchrotron, dynamic-aperture, damping, optics 3056
 
  • P. Zisopoulos, F. Antoniou, Y. Papaphilippou
    CERN, Geneva, Switzerland
  • A. Streun
    PSI, Villigen PSI, Switzerland
  • V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  
  Frequency Maps Analysis (FMA) has been widely used in beam dynamics in order to study dynamical aspects of the particles linear and non-linear motion, such as optics functions distortion, coupling, tune-shift and resonances. In this paper, FMA is employed to explore the dynamics of models of the Swiss Light Source (SLS) storage ring and compare them with measured turn by turn (TxT) position data. In particular, a method is proposed for estimating the momentum spread using synchrotron sidebands of the Fourier spectrum of the TxT data.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO076  
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THPRO079 Quantitative Analysis of Trapping Probability for Quasi-integrable Two-degree of Freedom Maps simulation, extraction, coupling, synchrotron 3065
 
  • M. Giovannozzi, C. Hernalsteens, J. Williams
    CERN, Geneva, Switzerland
  • A. Bazzani
    Bologna University, Bologna, Italy
  • C. Hernalsteens
    EPFL, Lausanne, Switzerland
  
  A key ingredient for the Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron is the beam trapping in stable islands of transverse phase space. In a previous paper a method allowing analytical estimation of the fraction of beam trapped into resonance islands as a function of the Hamiltonian parameters has been presented. Such a method applies to one-degree of freedom models of betatronic motion. In this paper, the analysis is extended to the more realistic and challenging case of two-degree of freedom systems, in which the interplay between the horizontal and vertical motion is fully included. Numerical simulations are presented and the results are discussed in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO079  
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THPRO088 Optimization of the pp AGS Zgoubi Model in the Low Energy Range simulation, emittance, acceleration, betatron 3089
 
  • Y. Dutheil, H. Huang, F. Méot, N. Tsoupas
    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.
At low energy the AGS lattice is strongly deformed by the two strong helical snakes, required to preserve the polarization. In addition to the complex, highly non-linear field featured by the two snakes, multiple non-linear coupling resonance lines are crossed by the beam in this region. Hence, the use of realistic models for the Siberian snakes is critical for the simulation of the early part of the AGS acceleration cycle. The AGS Zgoubi model uses direct tracking through OPERA field maps of the two snakes. While many processes may be obnoxious to both beam and spin dynamics in this region, it is critical to use a realistic model of the AGS at low energy. This paper presents the current model used and some of the challenges recently faced. We will also compare experimental beam dynamics results to those predicted by the Zgoubi model. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO088  
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THPRO089 New Tune Jumps Scheme in the Low Energy Part of the AGS Cycle polarization, simulation, acceleration, hardware 3092
 
  • Y. Dutheil, L. Ahrens, J.W. Glenn, H. Huang, F. Méot, V. Schoefer
    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.
During the early part of the acceleration of polarized protons, due to strong optical deformations of the lattice, the tune cannot be placed in the spin gap and the first two vertical intrinsic resonances are crossed. Recent multiparticle trackings using the Zgoubi code show that the spin resonances around Gg=5 could cause as much as 5% loss of polarization. The slow acceleration rate, the two vertical and two horizontal intrinsic spin resonances can contribute to the depolarization in the region. While in the current scheme only the two horizontal intrinsic resonances are jumped, it was proposed to use the tune jumps system to also accelerate the crossing of the two weak vertical intrinsic resonances and improve the polarization transmission through this region. We show the design of this new tune jumps scheme and the expected polarization gains expected from multiparticles Zgoubi simulations. We also compare experimental measurements of the polarization transmission to the Zgoubi simulations. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO089  
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THPRO090 Energy Calibration and Tune Jumps Efficiency in the pp AGS polarization, timing, acceleration, extraction 3095
 
  • Y. Dutheil, L. Ahrens, H. Huang, F. Méot, A. Poblaguev, V. Schoefer, K. Yip
    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.
The AGS tune jump system consists of two fast quadrupoles used to accelerate the crossing of 82 horizontal intrinsic spin resonances. The fast tune jump of ΔQh=+0.04 within 100 μs imposes perfect localization of each of the 82 resonant conditions. Imperfect timing of the tune jumps results in lower efficiency of the system and lower transmission of the polarization through the AGS acceleration cycle. Investigations during the end of the pp AGS Run13 revealed weaknesses in the energy measurement at high energy, causing less than optimal timing of the tune jumps. A new method based on continuous polarization measurement to determine the energy during the acceleration cycle has been developed. Strong operational constraints were taken into account to provide a convenient system of energy measurement. This is also used to calibrate the usual determination of the energy based on revolution frequency of the beam or measured dipole magnetic field. This paper shows the tools developed and the results of the first tests during the AGS Run 14. Simulations of the expected tune jumps efficiency using the AGS Zgoubi model are also presented and compared to experimental results. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO090  
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THPRO091 Strength of Horizontal Intrinsic Spin Resonances in the AGS polarization, emittance, optics, proton 3098
 
  • Y. Dutheil, L. Ahrens, J.W. Glenn, H. Huang, F. Méot, T. Roser, V. Schoefer
    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.
Crossing of horizontal intrinsic resonances is today the main source of polarization losses in the AGS, in its dual partial snakes configuration for polarized proton acceleration. Polarization losses were greatly reduced by the AGS tune jump system. However total polarization transmission through the AGS cycle is not yet achieved, still partially due to the horizontal intrinsic resonances. This paper will explore the effect of optical distortions and different horizontal tunes on the strength of horizontal intrinsic resonances. Various options will be presented and practicability will be addressed. Theoretical model and multiparticle trackings using the Zgoubi code will show the expected polarization gains of different scenarios. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO091  
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THPME037 Development of a 72.75 MHz RFQ for the LINCE Accelerator Complex rfq, quadrupole, Windows, simulation 3304
 
  • A.K. Orduz, C. Bonțoiu, I. Martel, A.C.C. Villari
    University of Huelva, Huelva, Spain
  • A. Garbayo
    AVS, Elgoibar, Spain
  • P.N. Ostroumov
    ANL, Argonne, Illinois, USA
  • A.C.C. Villari
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work partially supported by the Spanish Government (MINECO-CDTI) under program FEDER INTERCONNECTA.
Low-energy acceleration for the LINCE project [1] will be achieved using a 72.75 MHz normal conducting four vanes RFQ designed to give a 460 keV/u boost for A/Q = 7 ions in about 5 m. The vanes are modeled to accommodate windows for a clear separation of the RFQ modes and easy fitting to an octagonal resonance chamber. This article presents the main numerical results of the radio-frequency modeling and computational fluid dynamics (CFD). Particle tracking studies optimized for bunching and acceleration are shown as well.
[1] I. Martel et al., “LINCE: A High Intensity Multi-ion Superconducting Linac for Nuclear Structure and Reactions”, IPAC’14, Dresden, Germany, June 2014, THPME036, These Proceedings. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME037  
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THPME096 Goubau Line Beam Instrumentation Testing, The Benefits instrumentation, electromagnetic-fields, impedance, electronics 3462
 
  • F. Stulle, J.F. Bergoz
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • J. Musson
    JLab, Newport News, Virginia, USA
  
  At JLab and Bergoz Instrumentation Goubau lines are used for beam instrumentation testing. A Goubau line differs fundamentally from standard bench testing techniques in the way it produces the electromagnetic fields which interact with the DUT. This allows to acquire complementary information about DUT characteristics. Consequently, we improve our knowledge about the DUT. At JLab BPM responses have been successfully mapped and at Bergoz Instrumentation high frequency behavior of current transformers is under study. We present results, highlight benefits and outline ideas for future studies of additional accelerator components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME096  
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THPME147 The High Position Resolution Cavity BPM Developments and Measurement for ILC Final Focus System cavity, electronics, alignment, operation 3599
 
  • S.W. Jang, J.G. Hwang, E.-S. Kim, L. Lee
    KNU, Deagu, Republic of Korea
  • P. Bambade, O.R. Blanco-García, F. Bogard, S. Wallon
    LAL, Orsay, France
  • Y. Honda, T. Okugi, T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  
  An ultra high position resolution cavity BPM was developed for the final focus system of ATF2, which is a accelerator test facility for ILC final focus system. The main purpose of ATF2 are achievement of 37 nm beam size and nano-meter beam orbit stability at IP(Interaction Point). For these purposes, a few nano meter beam position resolution was required for this cavity BPM, which is called the IP-BPM. The IP-BPM was fabricated 2 blocks of IP-BPM, the first block consists of two cavities in one block and second block consists of single cavity. IP-BPM can measure beam position in vertical and horizontal independently by using rectangular shape single cavity. Three IP-BPMs were installed at ATF IP region inside IP-chamber, and its position resolution was measured. We will present the detailed results on the beam tests.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME147  
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THPME182 Precise Instruments for Bunch Charge Measurement pick-up, impedance, monitoring, vacuum 3703
 
  • A. Kalinin
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  For the pulse charge q injected into a capacitor of a parallel resonating circuit, the oscillation voltage V on a series resistor R is V=qwRexp(—wt/2Q)sin(wt–1/2Q), t>τ, where w is the resonance frequency, Q>>1 is the quality factor and τ<<1/w is the pulse length. Of the two main parameters, R is known, and w can be found directly from the signal above. The quality factor contribution is low, and its rough estimation is sufficient to retain voltage accuracy. The observations above open a possibility of precise bunch charge measurement. We describe a bunch charge monitor that is a cavity with a lump capacitor as a low impedance coaxial line connected to a gap in the vacuum pipe. An LC electronic circuit is also presented. It integrates the single bunch current delivered by a Faraday Cup, or a Wall Current Monitor, or a Fast Current Transformer. The circuit has w~30MHz, Q~20, and with a Faraday Cup, the lower range is 10pC/V and the noise floor is about 20fC. Several such circuits are in use on the VELA injector in Daresbury Laboratory.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME182  
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THPRI054 Permittivity and Permeability Measurement Methods for Particle Accelerator Related Materials impedance, simulation, cavity, HOM 3893
 
  • C. Vollinger, F. Caspers, E. Jensen
    CERN, Geneva, Switzerland
  
  For the special requirements related to particle accelerators, knowledge of the different material parameters of dielectrics and other materials are needed in order to carry out simulations during the design process of accelerator components. This includes also properties of magnetically biased ferrites of which usually little information is available about material characteristics, especially in magnetic bias fields. Several methods of measurement are discussed and compared of which some require delicate sample preparation whereas others can work with unmodified material shapes that makes those methods also suited for acceptance checks on incoming materials delivered by industry. Applications include characterization of different materials, as absorbers in which dielectric losses play an increasing role, as well as low frequency measurements on ferrites that are used for tunable cavities. We present results obtained from both broadband and resonant measurements on different materials determined in the same sample holder. Where possible, the results were confirmed with alternative methods.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI054  
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FRXAA01 Beam Dynamics Studies with Non-neutral Plasma Traps plasma, ion, experiment, focusing 4052
 
  • H. Okamoto, K. Fukushima, H. Higaki, K. Ito, K. Moriya, T. Okano, K. Osaki
    HU/AdSM, Higashi-Hiroshima, Japan
  
  Both Paul ion traps and Penning traps have been employed at Hiroshima University to explore fundamental aspects of space-charge dominated beam dynamics. These compact accelerator-free experiments are based on an isomorphism between non-neutral plasmas in a trap and charged-particle beams traveling in a periodic focusing channel. This talk highlights the recent experimental results on coherent betatron resonances in various strong-focusing lattices, resonance crossing in non-scaling FFAG accelerators, ultra-low emittance beam stability, and halo formation.  
slides icon Slides FRXAA01 [5.557 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-FRXAA01  
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