Keyword: betatron
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MOYCA01 Review of Linear Optics Measurements and Corrections in Accelerators optics, coupling, quadrupole, collider 20
 
  • R. Tomás
    CERN, Geneva, Switzerland
  • M. Aiba
    PSI, Villigen PSI, Switzerland
  • A. Franchi
    ESRF, Grenoble, France
  • U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  
  The measurement and correction of optics parameters has been a major concern since the advent of strong focusing synchrotron accelerators. Traditionally, colliders have led the development of methods for optics control based on turn-by-turn centroid data, while lepton storage rings have focused on closed orbit response techniques. Recently considerable efforts are being invested in comparing these techniques in different light sources and colliders. An emerging class of less invasive optics control techniques based on the optimization of performance related observables is demonstrating a great potential. A review of the existing techniques is presented highlighting comparisons, merits and limitations.  
slides icon Slides MOYCA01 [4.184 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOYCA01  
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MOOCB02 A Lattice Correction Approach through Betatron Phase Advance lattice, sextupole, simulation, dynamic-aperture 62
 
  • W. Guo, S.L. Kramer, F.J. Willeke, X. Yang, L. Yu
    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
Most lattice correction algorithms, such as LOCO, rely on the amplitude of the BPM signals. However, these signals are a mixture of the BPM gain and beta-beat. Even though BPM gain can be fitted by analyzing the statistics of all the BPMs in a ring accelerator, we found the uncertainty is on the order of a few percent. On the other hand, the betatron phase advance, which is obtained from the correlation of two adjacent BPMs, is independent of the BPM gain and tilt error. It was found at NSLS-II that the measurement precision of the phase advance is typically 0.001 radian, which corresponds to about 0.2% of beta beat. The phase error can be corrected similarly using a response matrix, and at NSLS-II the phase error can be corrected to <0.005 radian (p-p) in less than half an hour. The same technique can be applied to the nonlinear lattice. By comparing the phase advance differences between the on- and off- orbit lattices, the sextupole strength error can be identified. Simulation and experimental results will be demonstrated in the paper. 		 
slides icon Slides MOOCB02 [1.554 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOOCB02  
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MOPMR002 Bunch by Bunch Position Measurement and Analysis at PLS-II injection, kicker, operation, pick-up 232
 
  • J. Lee, M.-H. Chun, I. Hwang, D.T. Kim, G. Kim, T.-Y. Lee, D.C. Shin, S. Shin
    PAL, Pohang, Republic of Korea
  
  Beam dynamic phenomena described by bunch-by-bunch motion are important issues for a storage ring and are described by various theoretical formalisms. Direct measurements of the beam position related to different dynamical mechanisms are a useful information to accelerator optimization. In PLS-II, 20 GHz sampling oscilloscope synchronized with injection event (or triggered by beam loss signal) is used to measure direct bunch by bunch motion. Based on the measured data, the principal component analysis had been performed to get the insight into beam dynamic phenomena such as couple bunch instability and beam oscillation due to kicker leakage. In this paper, we will describe the measurement method and the result of analysis for coupled bunch instability.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR002  
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MOPMR015 Optical Fibers as a Tool for Gamma Beam Diagnostics at Medical Electron Accelerators target, detector, electron, radiation 258
 
  • A.I. Novokshonov, V.I. Bespalov, A. Potylitsyn, D.A. Shkitov, S.R. Uglov, A.V. Vukolov
    TPU, Tomsk, Russia
  
  Funding: This work was partially supported by the Russian Ministry of Education and Science within the program "Nauka" Grant № 3.709.2014/K.
The existing techniques for gamma beam diagnostics at medical accelerators based on X-ray films have several disadvantages such as insufficient spatial resolution, difficult realization and off-line mode. In the works*,** a feasibility of Cherenkov radiation (CR) in glass fibers for charged particle beam diagnostics was demonstrated. An application of glass fibers scanning for gamma beam diagnostics may have a lot advantages including a possibility of on-line measurements. For this goal we used optical fiber with 0.6 mm diameter and length up to 10 m. An efficiency of CR generation in such fibers and signal attenuation in a long fiber were investigated using the Tomsk microtron electron beam. The shape of gamma beam field produced by the medical SL-75-5MT 6 MeV electron accelerator was measured using the proposed technique. It is shown there it is possible to measure not only gamma beam spatial distribution, but also its angular distribution.
* Wulf, F. and Korfer, M. 2009 Proc. DIPAC2009 411.
** Murokh, A., Agustsson, R., Boucher, S., Frigola, P., Hodgetts, T., Ovodenko, A., Ruelas, M. and Tikhoplav, R. 2012 Proc. IPAC2012 996.
 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR015  
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MOPMR034 Precise Betastron Tune Measurement in TPS Storage Ring storage-ring, simulation, radiation, synchrotron-radiation 319
 
  • C.H. Chen, C.H. Chang, J.Y. Chen, M.-S. Chiu, S. Fann, C.H. Huang, T.Y. Lee, C.C. Liang, Y.-C. Liu, F.H. Tseng
    NSRRC, Hsinchu, Taiwan
  
  To acquire precise beam orbits from beam position monitors (BPMs) in storage ring is one of the most significant diagnosis to measure beam parameters. However, the precise spectrum analyses from BPM data acquisitions such as betatron tune, dynamics aperture and frequency map '..etc. that are depended on more accurate discrete Fourier transform (DFT) or the fast Fourier transform (FFT). A method of the fast Fourier transform correction (FFTc) was employed for the more accurate spectrum measurement in Taiwan Photon Source (TPS). We perform the accuracy and error analyses of this method from some spectral lines in two window functions. And the precise spectrum for betatron tune measurements and related results will be presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR034  
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MOPOR003 Simulation Studies and Measurements of Beam Instabilities Caused by the Kicker Impedance at High Intensities in the 3-GeV RCS of J-PARC simulation, impedance, kicker, injection 589
 
  • P.K. Saha, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, M. Nomura, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, M. Yamamoto
    JAEA/J-PARC, Tokai-mura, Japan
  
  The transverse impedance of the extraction kickers is a significant beam instability source in the 3-GeV Rapid Cycling Synchrotron of J-PARC. ORBIT code was developed for space charge and beam instability simulations by successfully introducing realistic time dependent machine parameters. The beam instability at high intensities, especially at the designed 1 MW beam power was found be very critical. As there was no practical measure yet to reduce the kicker impedance, a detail simulation studies were done in order to determine realistic machine parameters to suppress the beam instability. The simulation results were found to be very consistent with measurements to successfully accomplish 1 MW beam power. The simulation and beam study results in detail are presented in this paper.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR003  
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MOPOR011 Impedance Localization Measurements using AC Dipoles in the LHC impedance, dipole, quadrupole, optics 614
 
  • N. Biancacci, L.R. Carver, G. Papotti, T. Persson, B. Salvant, R. Tomás
    CERN, Geneva, Switzerland
  
  The knowledge of the LHC impedance is of primary importance to predict the machine performance and allow for the HL-LHC upgrade. The developed impedance model can be benchmarked with beam measurements in order to assess its validity and limit. This is routinely done, for example, moving the LHC collimator jaws and measuring the induced tune shift. In order to localize possible unknown impedance sources, the variation of phase advance with intensity between beam position monitors can be measured. In this work we will present the impedance localization measurements performed at injection in the LHC using AC dipoles as exciter as well as the underlying theory.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR011  
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MOPOR018 Single Bunch Instability Studies at Diamond Light Source impedance, simulation, coupling, synchrotron 637
 
  • E. Koukovini-Platia, M. Apollonio, R. Bartolini, R.T. Fielder, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
  
  Single bunch instability thresholds, the associated coherent tune shifts and the bunch lengthening have been studied at Diamond light source for nominal optics. Measurements were taken under different settings of chromaticity, radio-frequency (RF) voltage and aperture of the insertion devices (IDs). The macro-particle code sbtrack was used to evaluate the instability thresholds and bunch lengthening where different impedance contributions are taken into account such as the resistive wall impedance, a broad-band resonator model and inductive impedance for the longitudinal plane. A comparison of simulation using the developed model impedance with measurements is shown for all cases.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR018  
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MOPOR047 Numerical and Experimental Substantiation of the Ion Density Beam Transfer Function Measurements ion, electron, space-charge, accumulation 698
 
  • D. Sauerland, W. Hillert
    ELSA, Bonn, Germany
  
  Funding: Funded by the BMBF, Germany under grant 05K13PDA
In the ELSA stretcher ring electrons are accelerated to a beam energy of 3.2 GeV utilizing a fast energy ramp of 6 GeV/s. Ions being generated by collision with the residual gas molecules accumulate inside the beam potential, causing incoherent tune shifts and coherent beam instabilities. Since the ion induced incoherent tune shift rises linearly with the beam neutralisation, it offers a suitable approach for evaluating the efficiency of several ion clearing measures. It was indirectly measured using a new experimental approach: By measuring the beam transfer function using a broadband transversal kicker, one was able to perceive a shift and broadening of the tune peak. Both effects could be adequately parameterized providing a quantity proportional to the incoherent tune shift and thus the average neutralisation. The impact of incoherent effects to the coherent electron beam response during the measurement has not been subject to intensive theoretical attention yet. This leaves the obtained quantity unscaled. Here new numerical simulations and experimental investigations will be presented in order to further substantiate the results of this new method. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR047  
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TUPMR037 Betatron Core Driven Slow Extraction at CNAO and MedAustron extraction, synchrotron, resonance, proton 1330
 
  • M. G. Pullia, E. Bressi, L. Falbo, C. Priano, S. Rossi, C. Viviani
    CNAO Foundation, Milan, Italy
  • A. Garonna, M. Kronberger, T.K.D. Kulenkampff, C. Kurfürst, F. Osmić, L.C. Penescu, M.T.F. Pivi, C. Schmitzer, P. Urschütz, A. Wastl
    EBG MedAustron, Wr. Neustadt, Austria
  
  The Italian Centre for Hadrontherapy (CNAO) and the MedAustron Hadrontherapy Center in Austria are synchrotron-based medical therapy centers. The CNAO machine has five years of experience in patient treatments, whereas MedAustron will soon start patient treatments with protons. Their accelerator systems have common characteristics, in particular in regards to the extraction system: at acceleration flattop, particles are slowly driven through the third integer resonance longitudinally by a betatron core. This setup enables smooth extracted beam intensities. The rationale behind the use of a betatron core, its impact on the extracted beam quality and the performance from operation and commissioning of the two centers will be here presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR037  
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TUPMR038 The Experimental Beam Line at CNAO ion, proton, synchrotron, extraction 1334
 
  • M. G. Pullia, S. Alpegiani, J. Bosser, E. Bressi, L. Casalegno, G. Ciavola, M. Ciocca, M. Donetti, A. Facoetti, L. Falbo, M. Ferrarini, S. Foglio, S.G. Gioia, V. Lante, L. Lanzavecchia, R. Monferrato, A. Parravicini, M. Pezzetta, C. Priano, E. Rojatti, S. Rossi, S. Savazzi, S. Sironi, S. Toncelli, G. Venchi, B. Vischioni, S. Vitulli, C. Viviani
    CNAO Foundation, Milan, Italy
  • G. Battistoni
    Universita' degli Studi di Milano & INFN, Milano, Italy
  • L. Celona, S. Gammino, S. Passarello
    INFN/LNS, Catania, Italy
  • A. Clozza, E. Di Pasquale, A. Ghigo, L. Pellegrino, R. Ricci, U. Rotundo, C. Sanelli, G. Sensolini, M. Serio
    INFN/LNF, Frascati (Roma), Italy
  • M. Del Franco
    Consorzio Laboratorio Nicola Cabibbo, Frascati, Italy
  • S. Giordanengo
    INFN-Torino, Torino, Italy
  • A.G. Lanza
    INFN - Pavia, Pavia, Italy
  • R. Sacchi
    Torino University, Torino, Italy
  
  The CNAO center has been conceived since the beginning with three treatment rooms and an 'experimental room' where research can be carried out without hindering the clinical activity. The room itself was built since the beginning, but the beam line was planned at a second moment in time to give priority to the treatments. The experimental room beam line has now been designed to be 'general purpose', to be used for research in different fields. Possible activities could be, as an example, irradiation of cells, test of beam monitors, development of in-beam monitoring devices or radiation hardness studies. In a second stage a third source will be added to the present two in order to carry on experiments with additional ion species besides the two used presently for treatments, protons and carbon ions. In this paper a description of the design and of the construction status is given.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR038  
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TUPMR046 Sources of Emittance Growth at the CERN PS Booster to PS Transfer emittance, injection, kicker, optics 1352
 
  • W. Bartmann, J.L. Abelleira, F. Burkart, B. Goddard, J. Jentzsch, R. Ostojić
    CERN, Geneva, Switzerland
  
  The CERN PS Booster (PSB) has four vertically stacked rings. After extraction from each ring, the bunches are recombined in two stages, comprising septum and kicker systems, such that the accumulated bunch train is injected through a single line into the PS. Bunches from the four rings go through a different number of vertical bends, which leads to differences in the betatron and dispersion functions due to edge focussing. The fast pulsed systems at PSB extraction, recombination and PS injection lead to systematic errors of delivery precision at the injection point. These error sources are quantified in terms of emittance growth and particle loss. Mitigations to reduce the overall emittance growth at the PSB to PS transfer within the LHC injectors upgrade are presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR046  
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TUPMR054 Simulation of the FCC-hh Collimation System collimation, proton, insertion, simulation 1381
 
  • J. Molson, P. Bambade, S. Chancé, A. Faus-Golfe
    LAL, Orsay, France
  
  Funding: Funding from the European Union's Horizon 2020 research and innovation programme under grant No 654305. Funding also from ANR-11-IDEX-0003-02.
The proposed CERN FCC-hh proton-proton collider will operate at unprecedented per-particle (50 TeV) and total stored beam energies (8.4 GJ). These high energies create the requirement for an efficient collimation system in order to protect the accelerator components and experiments. In order to verify the performance of proposed collimation system designs, loss map simulations have been performed using the code Merlin. Results for the current baseline layout are presented for both betatron and off-momentum loss maps. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR054  
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TUPMR060 Improvement of 18 MeV Cyclotron Magnet Design by TOSCA Code cyclotron, simulation, resonance, factory 1397
 
  • N. Rahimpour Kalkhoran, H. Afarideh, R. Solhju
    AUT, Tehran, Iran
  • J.-S. Chai, M. Ghergherehchi
    SKKU, Suwon, Republic of Korea
  
  According to increasing need to cyclotrons in the world, designing and manufacturing of these machines are considered. Therefore designing of 18 MeV cyclotron magnet has begun at Amirkabir University Of Technology. Magnet is one of the most important parts of the cyclotron, so in designing of magnet, all other components of cyclotron which influence on magnet, should be considered. Since the achievable energy for particle is determined 18MeV, designed magnet has AVF structure. TOSCA (Opera-3D) code was selected for simulation and analysis. First of all, theoretical calculations and estimations were done and magnetic field data according to radius were achieved, after that, simulation with initial estimations and a simple model of magnet was begun and optimization process continued until magnetic field results from the simulation coincided with the theoretical one. Different shimmings were used for better coincidence. Some results contains magnetic field on middle plane and betatron oscillations were checked. Also working points of the cyclotron with resonance regions were checked. According to use reliable mesh, the accuracy of simulation results is sufficient high.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR060  
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TUPMW013 Experimental Demonstration of β* Leveling at the LHC luminosity, controls, experiment, emittance 1442
 
  • A.A. Gorzawski, D. Mirarchi, B. Salvachua, J. Wenninger
    CERN, Geneva, Switzerland
  
  The HL-LHC project foresees to boost the LHC peak luminosity beyond the capabilities of the LHC experimental detectors. Leveling the luminosity down to a constant value that is sustainable for the experiments is therefore the operational baseline of HL-LHC. Various luminosity leveling techniques are available at the LHC. Leveling by adjusting β*, the betatron function at the interaction point, to maintain a constant luminosity is favorable because the beams remain head-on which provides optimal stability from the point of view of collective effects. Smooth leveling by β* requires however excellent control of the beam orbits and beam losses in the interaction regions since the beam offsets should not vary by more than around one r.m.s. beam size during the process. This leveling scheme has been successfully tested and experimentally demonstrated during the LHC machine development program in 2015. This paper presents results on luminosity leveling over a β* range from 10 m to 0.8 m and provides an outlook on future developments and use of this technique at the LHC.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW013  
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TUPMW031 Combined Ramp and Squeeze to 6.5 TeV in the LHC optics, operation, controls, dipole 1509
 
  • M. Solfaroli Camillocci, S. Redaelli, R. Tomás, J. Wenninger
    CERN, Geneva, Switzerland
  
  The cycle of the LHC is composed of an energy ramp followed by a betatron squeeze, needed to reduce the beta- star value in the interaction points. Since Run 1, studies have been carried out to investigate the feasibility of combining the two operations, thus considerably reducing the duration of the operational cycle. In Run 2, the LHC is operating at the energy of 6.5 TeV that requires a much longer cycle than that of Run 1. Therefore, the performance gains from a Combined Ramp and Squeeze (CRS) is more interesting. Merging the energy ramp and the betatron squeeze could result in a gain of several minutes for each LHC cycle. With increasing maturity of LHC operation, it is now possible to envisage more complex beam manipulations; this paper describes the first machine experiment with beam, aiming at validating the combination of ramp and squeeze, which was performed in 2015, during a machine development phase. The operation experience with the LHC run at 2.51 TeV, when CRS down to 4 meters was deployed and a the first results of 2016 run are also reviewed.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW031  
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TUPMY004 The MICE Demonstration of Muon Ionization Cooling emittance, lattice, simulation, experiment 1547
 
  • J.-B. Lagrange, C. Hunt, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • V.C. Palladino
    INFN-Napoli, Napoli, Italy
  • J. Pasternak
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  
  Funding: STFC, DOE, NSF, INFN, CHIPP AND MORE
Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions up to several TeV at the Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate muon ionization cooling, the technique proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization-cooling channel, the muon beam traverses a material (the absorber) loosing energy, which is replaced using RF cavities. The combined effect is to reduce the transverse emittance of the beam (transverse cooling). The configuration of MICE required to deliver the demonstration of ionization cooling is being prepared in parallel to the execution of a programme designed to measure the cooling properties of liquid-hydrogen and lithium hydride. The design of the cooling-demonstration experiment will be presented together with a summary of the performance of each of its components and the cooling performance of the experiment.
Submitted by the MICE speakers bureau that will identify later a member of the collaboration to present the contribution 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY004  
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TUPOR029 Study of Fast Instability in Fermilab Recycler electron, simulation, dipole, proton 1728
 
  • S. A. Antipov
    University of Chicago, Chicago, Illinois, USA
  • P. Adamson, S. Nagaitsev, M.-J. Yang
    Fermilab, Batavia, Illinois, USA
  
  One of the factors which may limit the intensity in the Fermilab Recycler is a fast transverse instability. It develops within a hundred turns and, in certain conditions, may lead to a beam loss. Various peculiar features of the instability: its occurrence only above a certain intensity threshold, and only in horizontal plane, as well as the rate of the instability, suggest that its cause is electron cloud. We studied the phenomena by observing the dynamics of stable and unstable beam. We found that beam motion can be stabilized by a clearing bunch, which confirms the electron cloud nature of the instability. The findings suggest electron cloud trapping in Recycler combined function mag-nets. Bunch-by-bunch measurements of betatron tune show a tune shift towards the end of the bunch train and allow the estimation of the density of electron cloud and the rate of its build-up. The experimental results are in agreement with numerical simulations of electron cloud build-up and its interaction with the beam.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR029  
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TUPOR033 Experimental Study of Single Bunch Instabilities at NSLS-II Storage Ring synchrotron, feedback, storage-ring, lattice 1738
 
  • W.X. Cheng, B. Bacha, G. Bassi, A. Blednykh, B. Podobedov, O. Singh, V. Smalyuk
    BNL, Upton, Long Island, New York, USA
  
  Single bunch instabilities have been observed since the early stage of NSLS-II storage ring commissioning. After installing the super-conducting cavity, the single bunch instability threshold current was similar at 0.7mA. The instability was eventually determined to be due to transverse mode coupling. Microwave instability has been characterized using streak camera bunch profile, horizontal beam sizes at dispersion location and beam spectrums. Microwave instability threshold current dependency on bunch lengths and IUV gaps has been studied. Most recent experimental results will be presented in this paper.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR033  
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WEPMR034 Analyses of 476 MHz and 952 MHz Crab Cavities for JLAB Electron Ion Collider cavity, ion, collider, electron 2348
 
  • H. Park, A. Castilla, S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • V.S. Morozov
    JLab, Newport News, Virginia, USA
  
  Center for Accelerator Science at ODU has designed, fabricated and successfully tested a crab cavity for MEIC at Jefferson Lab*. This proof of principle cavity was based on the earlier MEIC design which used 748.5 MHz RF system. The updated MEIC design** utilizes the components from PEP-II. It results in the change on the bunch repetition rate of stored beam to 476.3 MHz. The ion ring collider will eventually require 952.6 MHz crab cavity. This paper will present the analyses of crab cavities of both 476 MHz and 952 MHz options. It compares advantages and disadvantages of the options which provides the MEIC design team important technical information for a system down selection.
* Cryogenic Test of a 750 MHz Superconducting RF Dipole Crabbing Cavity, A. castilla et al, IPAC2014
** MEIC Design Summary, S. Abeyratne et al, arXiv:1504.07961 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR034  
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WEPMW006 First Design of a Proton Collimation System for 50 TeV FCC-hh collimation, insertion, collider, proton 2423
 
  • M. Fiascaris, R. Bruce, D. Mirarchi, S. Redaelli
    CERN, Geneva, Switzerland
  
  We present studies aimed at defining a first conceptual solution for a collimation system for the hadron-hadron option for the Future Circular Collider (FCC-hh). The baseline collimation layout is based on the scaling of the present LHC collimation system to the FCC-hh energy. It currently includes a dedicated betatron cleaning insertion as well as collimators in the experimental insertions to protect the inner triplets. An aperture model for the FCC-hh is defined and the geometrical acceptance is calculated at top energy taking into account mechanical and optics imperfections. Based on these studies the collimator settings needed to protect the machine are defined. The performance of the collimation system is then assessed with particle tracking simulation tools assuming a perfect machine.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW006  
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WEPMW037 MERLIN Simulations of the LHC Collimation System with 6.5 TeV Beams collimation, simulation, proton, scattering 2518
 
  • A. Valloni
    Rome University La Sapienza, Roma, Italy
  • R.B. Appleby, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • R. Bruce, A. Mereghetti, S. Redaelli
    CERN, Geneva, Switzerland
  • J. Molson
    LAL, Orsay, France
  • H. Rafique
    University of Huddersfield, Huddersfield, United Kingdom
  
  The accelerator physics code MERLIN has been extended in many areas to make detailed studies of the LHC collima- tion system and calculate loss maps from beam halo losses. Large scale tracking simulations have been produced for the 2015 run configuration at 6.5 TeV. We present results of cleaning inefficiency simulations of the LHC's multi-stage collimation system along with a detailed comparison be- tween MERLIN, SixTrack, and measured beam losses.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW037  
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WEPOW028 Applications of the Tune Measurement System of the HLS-II Storage Ring storage-ring, sextupole, quadrupole, EPICS 2892
 
  • J.J. Zheng, C. Cheng, X.Y. Liu, B.G. Sun, L.L. Tang, F.F. Wu, Y.L. Yang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: Work supported by National Natural Science Foundation of China (11105141, 11175173)
During the commissioning phase of the HLS-II storage ring, the betatron function, the natural chromaticity, the corrected chromaticity and the central RF frequency were measured using the Swept-Frequency-Exitation based tune measurement system. The betatron function was measured using the quadrupole modulation method. The natural chromaticity and the corrected chromaticity were measured using the dipole modulation method and the RF modulation method respectively. In addtion, the central RF frequency was measured using the sextupole modulation method, which can be viewed as a direct measure of the ring circumference. This paper describes the measurement details and presents the measurement results. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW028  
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WEPOW057 Spectral Analysis of Turn-by-Turn Data simulation, storage-ring, collective-effects, Windows 2979
 
  • J. Choi
    BNL, Upton, Long Island, New York, USA
  
  Funding: DOE contract No: DE-SC0012704
With the recent technical developments, it is now popular to get the turn-by-turn data for the storage ring. Even though response matrix based analysis, like LOCO, have strong advantages in lattice analysis, the turn-by-turn data analysis is quite attractive because it takes very short time in data acquisition and many effective analyzing methods have been developed. Basically, such analysis requires accurate estimation of peaks of frequency spectra with high resolution. In this paper, we review the various accuratenesses of such estimations depending on processes using exact sinusoidal data and apply the end-matching method to simulation and measurement. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW057  
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WEPOY030 First BTF Measurements at the Large Hadron Collider octupole, injection, damping, simulation 3051
 
  • C. Tambasco, A. Boccardi, X. Buffat, K. Fuchsberger, M. Gąsior, R. Giachino, T. Lefèvre, T.E. Levens, T. Pieloni, M. Pojer, B. Salvachua, M. Solfaroli Camillocci
    CERN, Geneva, Switzerland
  • J. Barranco, C. Tambasco
    EPFL, Lausanne, Switzerland
  
  During the Run I in 2012, several instabilities have been observed at the Large Hadron Collider (LHC) during the Betatron squeeze. The predictions of instability thresholds are based on the computation of the beam Landau damping by calculating the Stability Diagrams (SD). These instabilities could be explained by a deterioration of the SD due to beam-beam resonance excitation which could change the particle distributions. Beam Transfer Functions (BTF) provide a measurement of the Stability Diagram. The BTFs are sensitive to the particle detuning with amplitude as well as to the particle distributions therefore they represent a powerful tool to understand experimentally the stability of beams during the LHC operational cycle. First BTF measurements at the LHC are presented for different machine configurations and settings and compared to predictions.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY030  
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WEPOY054 A Matlab Interface Package for Elegant Simulation Code lattice, booster, quadrupole, space-charge 3117
 
  • V.V. Smaluk, T.V. Shaftan, G.M. Wang
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by DOE contract DE-AC02-98CH10886
A Matlab interface package for Elegant simulation code is under development. This package combines advantages of Elegant, which is one of the most advanced codes for accelerator simulations, with advantages of useful and effective Matlab functions for data processing, analysis, optimization, and real-time machine control using Maltab Middle Layer. A number of functions have been already developed: calculation of lattice parameters and Twiss functions, linear and high-order chromaticity, amplitude-dependent tune shifts, modification of lattice elements, correction of betatron tunes and chromaticity, a set of functions for graphic representation. These functions have been successfully used at NSLS-II for tracking and turn-by-turn simulations near the half-integer resonance, for maximizing tunability and dynamic aperture of NSLS-II Booster, and for calculating limits of top-up Booster energy interlock. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY054  
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THPMB008 Compensation of Steerer Crosstalk between FLASH1 and FLASH2 electron, laser, FEL, free-electron-laser 3237
 
  • F. Christie, B. Schmidt, M. Vogt
    DESY, Hamburg, Germany
  
  The free-electron laser in Hamburg (FLASH) is a user facility delivering soft X-ray radiation. Starting from 2014, a second beam line for user operation, FLASH2, has been commissioned. It uses the same accelerating modules as the initial FLASH beam line (FLASH1) and the beam is deflected into a separate beam line downstream the linac. In the region, where the FLASH2 beam is extracted, both beam lines are close, the angle in between is 6.5 degrees. It has been observed, that steering dipoles in the extraction area, have an influence on both beam lines. Thus steering the orbit in one beam line, perturbs the orbit in the other beam line. This perturbation can significantly degrade the SASE energy in the other beam line. We have found a solution to this problem based the combination of local orbit bumps. The crosstalk from one steerer is corrected using additional steerers in the other beam line. This concept has already been tested at FLASH and has proven to work sufficiently well.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB008  
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THPMB022 Direct and High Resolution Beta-Function Measurements for Storage Ring Lattice Characterization quadrupole, lattice, storage-ring, closed-orbit 3272
 
  • W. Li, H. Hao, Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
  • W. Li, W. Xu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Betatron functions are a set of commonly used merits to characterize the lattice performance of a circular accelerator. The betatron functions in many accelerators can be computed using a lattice model trained or calibrated using a set of closed orbit responses, which is exemplified by the widely used LOCO technique. However, for some accelerators, like Duke storage ring with quad-sextupole combined function magnets, LOCO cannot be employed in any straight forward manner. In this case, direct measurements for betatron function are required. One way to determine betatron functions at the location of quadrupoles for a circular accelerator is to use the relationship between the quadrupole strength variations and the corresponding betatron tune change. In this paper, we present a set of carefully developed techniques to accurately measure the betatron functions at the location of quadrupoles, which allow us to achieve extremely high accuracy. Measurement errors will be discussed, and the detailed measurement technique will be present. Finally, we'll report preliminary experimental results of beta function measurements in the Duke storage ring with statistical error on the order of 1%.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB022  
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THPMR008 Experimental Crosscheck of Algorithms for Magnet Lattice Correction lattice, optics, quadrupole, storage-ring 3400
 
  • V.V. Smaluk, W. Guo, Y. Hidaka, Y. Li, G.M. Wang, L. Yang, X. Yang
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by DOE contract DE-AC02-98CH10886
Performance, capabilities and limitations of various algorithms for linear magnet optics correction have been studied experimentally at NSLS-II. For the crosscheck, we have selected 4 algorithms based on turn-by-turn beam position analysis: weighted correction of betatron phase and amplitude, independent component analysis, model-independent analysis, and driving-terms-based linear optics characterization. A LOCO algorithm based on closed orbit measurement has been used as a reference. For the correction, either iterative solving of linear problem (matrix inversion with singular-value decomposition) or variational optimization has been used. For all the algorithms, accuracy limitations and convergence of linear lattice correction are discussed. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR008  
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THPMR012 Optimization of Nonlinear Dynamics for Sirius lattice, sextupole, dynamic-aperture, optics 3409
 
  • F.H. de Sá, L. Liu, X.R. Resende
    LNLS, Campinas, Brazil
  
  In this work we describe the optimization of the non-linear dynamics for the Sirius storage ring. The strong sextupoles of the lattice, necessary to correct the linear chromaticities, generate higher order terms in the tune-shifts with amplitude and energy, which may result in a large tune footprint for the machine. The configuration the sextupole families found that wraps this tune footprint and thus avoids dangerous resonances was achieved with minimization of Hamiltonian driving terms and tracking-based multi-objective algorithms include realistic values of misalignment and excitation errors of the magnets, orbit correction, insertion devices fields and real vacuum chamber apertures.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR012  
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THPMR022 Non-linear Optimization of Storage Ring Lattice for the SPring-8 Upgrade sextupole, lattice, optics, injection 3440
 
  • K. Soutome, K.K. Kaneki, Y. Shimosaki, M. Takao
    JASRI/SPring-8, Hyogo-ken, Japan
  • H. Tanaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  
  A project of upgrading the SPring-8 facility is ongoing to convert the present storage ring to a high-coherence hard X-ray source (SPring-8-II). To achieve the emittance value of less than 0.2 nmrad at 6 GeV, we adopted a 5-bend achromat lattice with dipoles having longitudinal field gradient. In this lattice the betatron phase between the two dispersion arcs was set to (2n+1)PI to suppress dominant harmful effects of chromaticity-correcting sextupoles. By detuning this phase, optimizing sextupole strengths in a cell and introducing octupoles, we obtained a sufficient dynamic aperture (DA) for beam injection even for the symmetry-broken ring having four long straight sections and a high-beta injection section. However, the off-momentum behavior such as the non-linear chromaticity still needs to be optimized to achieve the momentum acceptance (MA) of 3% or larger. We have thus been investigating the possibility to increase both the DA and MA by introducing several phase-matched sextupole pairs. The presentation will report the obtained results by this approach.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR022  
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THPMR031 Turn-by-Turn Measurements for Beam Dynamics at Vepp-5 Damping Ring impedance, damping, lattice, vacuum 3452
 
  • M.F. Blinov, K.V. Astrelina, V.V. Balakin, O.I. Meshkov, A.A. Starostenko
    BINP SB RAS, Novosibirsk, Russia
  • V.L. Dorokhov
    BINP, Novosibirsk, Russia
  
  Preinjector complex VEPP-5 is being constructed for high rate production and acceleration of electrons and positrons beams up to energy 510 MeV. Both kinds of particles accumulated in the damping ring and after achieving of needed intensity the beams would be transported alternatively to VEPP-3/VEPP-4M or to BEP/VEPP-2000 colliders. At this paper basic parameters of damping ring presented. All measurements were carried out for electron beam with energy 385 MeV. For turn-by-turn measurements 12 beam position monitors were used. In order to improve precision of measured value NAFF algorithm was applied. For measurements of longitudinal beam profile optical phi-dissector was used.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR031  
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THPMR037 Observations of Resonance Driving Terms in the LHC during Runs I and II resonance, dipole, injection, dynamic-aperture 3468
 
  • F.S. Carlier, J.M. Coello de Portugal, E.H. Maclean, T. Persson, R. Tomás
    CERN, Geneva, Switzerland
  
  Future operations of the LHC will require a good understanding of the nonlinear beam dynamics. In 2012, turn-by-turn measurements of large diagonal betatron excitations in LHC Beam 2 were taken at injection energy. Spectral analysis of these measurements shows an anomalous octupolar spectral line at frequency -Qx-2Qy in the horizontal motion. The presence of this spectral line, as well as other lines, was confirmed by measurements taken for LHC Beam 1 and Beam 2 during the commissioning in 2015. We take a close look at the various spectral lines appearing in the LHC transverse motion in order to improve the LHC nonlinear model.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR037  
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THPOR025 Wedge Absorbers for Final Cooling for a High-Energy High-Luminosity Lepton Collider emittance, experiment, optics, collider 3832
 
  • D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  • T.A. Mohayai
    IIT, Chicago, Illinois, USA
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illinois, USA
  • D.J. Summers
    UMiss, University, Mississippi, USA
  
  Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy.
A high-energy high-luminosity muon collider scenario requires a "final cooling" system that reduces transverse emittance to ~25 microns (normalized) while allowing longitudinal emittance increase. Ionization cooling using high-field solenoids (or Li Lens) can reduce transverse emittances to ~100 microns in readily achievable configurations, confirmed by simulation. Passing these muon beams at ~100 MeV/c through cm-sized diamond wedges can reduce transverse emittances to ~25 microns, while increasing longitudinal emittance by a factor of ~5. Implementation will require optical matching of the exiting beam into downstream acceleration systems. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR025  
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THPOW039 Measurements of the Lattice Modifications for the Cryogenic Undulator CPMU17 undulator, optics, quadrupole, storage-ring 4031
 
  • J. Bahrdt, D.B. Engel, W. Frentrup, P. Goslawski, P. Kuske, R. Müller, M. Ries, M. Ruprecht, A. Schälicke
    HZB, Berlin, Germany
  
  A 2 mrad-canted double undulator system is in preparation as the wide energy range light source for the Energy Material in-situ Laboratory EMIL at the HZB storage ring BESSY II. The cryogenic undulator CPMU-17 is the hard X-ray device of the double undulator system. The soft X-ray undulator UE-48 is of the APPLE II type. It was installed and commissioned a few months ago, whereas the CPMU-17 is under fabrication. The CPMU-17 will employ a minimum magnetic gap of 5.5mm. Including a CuNi-foil for RF-shielding and geometric tolerances the free aperture is planned to be 5.0 mm. The BESSY II lattice has been modified locally in order to cope with the small gap device. The adapted betatron functions with a shifted vertical beam waist were measured and fitted with LOCO. The new optics agrees with the predicted performance. The free aperture at the installation place of the CPMU-17 was measured with four vertical scrapers. It is compatible with the projected minimum undulator gap. Finally, the measured injection efficiency with the new EMIL optics switched on is compatible with top-up operation (injection efficiency ≥ 90 %).  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW039  
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