Keyword: sextupole
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MOPIK046 Phase Space Folding Studies for Beam Loss Reduction During Resonant Slow Extraction at the CERN SPS extraction, multipole, simulation, proton 615
 
  • L.S. Stoel, M. Benedikt, K. Cornelis, M.A. Fraser, B. Goddard, V. Kain, F.M. Velotti
    CERN, Geneva, Switzerland
  
  The requested number of protons slow-extracted from the CERN Super Proton Synchrotron (SPS) for Fixed Target (FT) physics is expected to continue increasing in the coming years, especially if the proposed SPS Beam Dump Facility is realised. Limits on the extracted intensity are already being considered to mitigate the dose to personnel during interventions required to maintain the extraction equipment, especially the electrostatic extraction septum. In addition to other on-going studies and technical developments, a reduction of the beam loss per extracted proton will play a crucial role in the future performance reach of the FT experimental programme at the SPS. In this paper a concept is investigated to reduce the fraction of beam impacting the extraction septum by folding the arm of the phase space separatrix. Beam dynamics simulations for the concept are presented and compared to the phase space acceptance of the extraction channel. The performance potential of the concept at SPS is evaluated and discussed alongside the necessary changes to the non-linear optical elements in the machine.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK046  
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MOPIK055 Beam by Design: Current Pulse Shaping Through Longitudinal Dispersion Control electron, simulation, synchrotron, laser 644
 
  • T.K. Charles, D.M. Paganin
    Monash University, Faculty of Science, Clayton, Victoria, Australia
  • M.J. Boland
    The University of Melbourne, Melbourne, Victoria, Australia
  • M.J. Boland, R.T. Dowd
    SLSA, Clayton, Australia
  
  Electron beams traversing a dispersive region, such as a bunch compressor and some transport line can form caustic lines and surfaces corresponding to regions of maximum electron density, which influence the current pulse shape. In this paper, we present a technique to manipulate the longitudinal phase space distribution to achieve an arbitrary, desired current pulse shape. We show how sextupole magnets (and in certain circumstances, octupole magnets), placed within a dispersive region can be used to generate the conditions required for a flexible technique of current pulse shaping that avoids truncation through collimation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK055  
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MOPIK059 Linear and Nonlinear Optimizations of Combined 7BA-6BA Lattices for the Future Upgrade of SOLEIL emittance, lattice, injection, dipole 659
 
  • A. Loulergue, P. Brunelle, H.C. Chao, A. Nadji, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
  
  Previous MBA studies converged to a combination of 7BA and 6BA structures, in terms of the target horizontal emittance of below 300 pm-rad, where the effect of anti-bends, dipole field values, and straight section lengths were investigated. Inspired by the successful lattice designs elsewhere adopting the interleaved sextupole scheme with dispersion bumps originally developed at the ESRF, the 7BA-6BA structures adopting this scheme are studied in details in parallel to those without it. The former aims at the horizontal emittance in the 200-300 pm-rad range with on and off-momentum dynamic acceptances sufficiently large for off-axis injection and good Touschek lifetime. The latter pursues the lower bound of the reachable horizontal emittance with quadrupole and sextupole strengths in the feasible range with maximum dynamic acceptance. The option of non-standard on-axis injection such as displacing the injected beam longitudinally is envisaged for the latter solutions. In both lattices, the numerical search using MOGA-based codes is employed extensively. The studies focus on the impact of linear optics and straight section lengths on the off-momentum and nonlinear properties.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK059  
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MOPIK060 Applying MOGA to Search Linear Lattice in Soleil Upgrade Project lattice, emittance, synchrotron, quadrupole 662
 
  • H.C. Chao, P. Brunelle, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  
  In the community of synchrotron radiation facilities, multi-bend structure becomes the trend of the storage ring design toward lower emittance. For SOLEIL upgrade project, the 7BA-6BA hybrid structure is one of the current options. This paper puts the focus on the 7BA section. There are many degrees of freedom to tweak and many constraints to follow. Here, the idea is to search and build the linear lattice utilizing Multi-Objective Genetic Algorithm (MOGA), which is efficient dealing with higher dimension optimization problems. Within MOGA, subsidiary matchings are performed to ensure certain criteria when the new generation is bred. Delicate designs and manipulations of the objective functions are needed, in order to have a better convergence without being trapped in a local minimum. The results will be shown and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK060  
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MOPIK063 Non-Linear Kickers Using Eddy Current Screens and Application to the ESRF injection, kicker, storage-ring, flattop 670
 
  • S.M. White, M. Dubrulle, L. Farvacque, P. Henrissat, G. Le Bec, E. Plouviez, P. Raimondi, C. Richard
    ESRF, Grenoble, France
  
  The ESRF storage ring injection and accumulation is performed using standard 4-kickers bump and septum magnet. Sextupoles are located within the injection bump leading to significant bump non-closure during the ramp-up and ramp-down and optics distorsion for both stored and injected beam. Introducing non-linearities in the kickers allows for compensation of the perturbation from these sextupoles. We report on the feasibility of adding eddy current screens to a standard kicker magnet design to generate a non-linear field and its recent application to mitigate the injection perturbations at the ESRF.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK063  
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MOPIK073 Calibration of Linear Optics of COSY Based on ORM Data quadrupole, factory, dipole, optics 699
 
  • C. Weidemann, M. Bai, Y. Dutheil, F. Hinder, B. Lorentz
    FZJ, Jülich, Germany
  
  The COoler SYnchrotron in Jülich is a well suited accelerator for a precursor experiment on the direct measurement of the Electric Dipole Moment (EDM) of the deuteron (see* and references within). It provides polarized and unpolarized proton and deuteron beams in the momentum range between 0.3 GeV/c and 3.65 GeV/c**, allows for phase space cooling and is highly flexible with respect to ion-optical settings***. Unfortunately, a model independent linear optics measurement is not possible and so far the existing MAD-X model of COSY does not provide an agreement with the actual machine parameters that is required by future experiments, such as the EDM experiment. Significant deviations with respect to the working point and linear optics have been reported****. As shown in*****, a MAD-X based LOCO (Linear Optics from Closed Orbits) algorithm in a C++ program was successfully developed and carefully benchmarked. This contribution presents the application of the new program on measured ORM data and its capabilities in calibrating linear optics as well as reconstructing machine imperfections such as gradient errors of quadrupole magnets and calibration factors of BPMs and steerers.
* D. Eversmann et al., PRL 115, no. 9, 094801 (2015).
** R. Maier, NIM A 390, 1 (1997).
*** C. Weidemann et al., PRSTAB 18, 020101 (2015).
**** D. Ji et al., IPAC16, doi:10.18429/JACoW-IPAC2016-TUPMR026.
***** C. Weidemann et al., IPAC16, doi:10.18429/JACoW-IPAC2016-THPMB009. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK073  
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MOPIK076 Optimization of Dynamic Aperture with Constraints on Linear Chromaticity luminosity, coupling, simulation, lattice 705
 
  • H. Sugimoto, H. Koiso, A. Morita, Y. Ohnishi, K. Oide, D. Zhou
    KEK, Ibaraki, Japan
  
  This paper presents numerical technique to optimize dynamic aperture with constraints on linear chromaticity of optical functions. By solving a set of linear equations at each iteration step of dynamic aperture optimization, the linear chromaticity is kept unchanged. The variable range of tuning knobs is taken into account in order to make the technique applicable to practical use. Numerical simulations assuming the SuperKEKB design lattice are performed, and it is demonstrated that the dynamic aperture obtained with the presented scheme is almost comparable to that without constraints. Luminosity simulations assuming weak-strong model show that the constraints lead to improvements of luminosity performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK076  
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MOPIK081 Study of HEPS Performance with Error Model and Simulated Correction optics, quadrupole, closed-orbit, simulation 721
 
  • D. Ji, Z. Duan, S.K. Tian, Y. Wei
    IHEP, Beijing, People's Republic of China
  
  As an important component of physics study on High Energy Photon Source (HEPS), error modelling and simu-lated correction will provide the guideline to restrict the manufacture redundancy of the hardware and estimate the real machine performance. In this paper, we present some work on error effect evaluation and simulated commis-sioning based on a recent lattice design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK081  
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MOPIK087 Development of a Tune Knob for the HLS-II Storage Ring quadrupole, storage-ring, lattice, simulation 730
 
  • S.W. Wang, J.Y. Li, W.B. Wu, W. Xu, K. Xuan, X. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  A tune knob is a useful tool for lattice setup and machine studies in a storage ring. It is used to adjust the transverse tunes with a small impact on the beam dynamics. A global tune knob is designed for the Hefei Light Source (HLS). In the tune knob, the quadrupoles are grouped into four families and are symmetrically adjusted. Methodical Accelerator Design-X (MAD-X) is used to calculate the coefficients of the tune knob and the Accelerator Toolbox (AT) is used to double check the accuracy of the tune knob. The chromaticity is corrected by the sextupoles in the storage ring. This paper reports preliminary simulation results of the tune knob for HLS. The beta function deviations are also studied.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK087  
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MOPIK088 Vertical Emittance Reduction in the SSRF Phase II Project emittance, coupling, quadrupole, alignment 733
 
  • C.L. Li, B.C. Jiang, Z.B. Li, M.Z. Zhang, Q.L. Zhang, W.Z. Zhang
    SINAP, Shanghai, People's Republic of China
  
  The Shanghai Synchrotron Radiation Facility (SSRF) Phase II beamline project (SSRF Phase II) will implement the new lattice with dual-canted insertion devices, superbends and superconducting wiggler. The emittance coupling is one of the most important parameters for the high brightness storage ring light sources. It is often less than 1% in the third-generation storage ring light sources. In this paper, the sensitivity of emittance coupling to magnetic alignment errors in the SSRF Phase II is presented. Sixty skew quadrupole magnets are utilized to correct the emittance coupling with gradient descent algorithm. The emittance coupling obtained in the SSRF Phase II lattice is below 0.3%.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK088  
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MOPIK090 Beta Function Measurement in the SOLARIS Storage Ring quadrupole, storage-ring, lattice, optics 736
 
  • A. Kisiel, M.B. Jaglarz, M.P. Kopeć, S. Piela, M.J. Stankiewicz, A.I. Wawrzyniak
    Solaris, Kraków, Poland
  
  One of the most essential lattice function used for transverse beam dynamics studies of the storage rings is a beta function. It characterizes the linear properties of magnets layout and allows to optimize the compatibility of the model and the machine by reducing the beta-beating. Moreover, the calculation of other parameters like transverse beam emittance, dynamic aperture, energy spread and others, requires knowledge of the quantity of beta function along the ring. Various methods of measurement of this function used in Solaris will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK090  
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MOPIK097 Vertical Dispersion and Betatron Coupling Correction for FCC-ee emittance, quadrupole, coupling, collider 752
 
  • S. Aumon, B.J. Holzer
    CERN, Geneva, Switzerland
  • K. Oide
    KEK, Ibaraki, Japan
  
  The FCC-ee project foresees to build a 100 km e+/e− circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 1035 cm-2s-1. To reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2~mm at the IPs. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 1~nm for εx and 2~pm for εy, bringing down the coupling ratio to 2/1000. Thus, coupling and vertical dispersion sources have to be controlled carefully. This paper describes the tolerance of the machine to magnet alignment errors as well as the optics correction methods that were implemented, such as the Orbit Dispersion Free Steering, in order to bring the vertical dispersion to reasonable values. The correction of the betatron coupling, being also a very important source of emittance growth, has been integrated to a challenging correction scheme to keep the vertical emittance as low as possible.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK097  
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MOPIK099 Tuning-Based Design Optimization of CLIC Final Focus System at 3 TeV luminosity, lattice, collider, linear-collider 760
 
  • F. Plassard, A. Latina, E. Marín, D. Schulte, R. Tomás
    CERN, Geneva, Switzerland
  • P. Bambade
    LAL, Orsay, France
  
  The tuning aims to mitigate static imperfections of the Final Focus System (FFS) for emittance preservation at the Interaction Point (IP). A simulation campaign on the nominal CLIC FFS at 3 TeV have shown the need of rethink the design in order to ease the tuning of the machine. The goal is to optimize the lattice in order to make the FFS more tolerant to misalignments by reducing the strength of the sextupoles. The tuning efficiency is promoted as figure of merit to find the optimal layout of the FFS. A comparative study of the tuning performances have been performed for two L* options.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK099  
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MOPIK100 Beam Delivery System Optimization for CLIC 380 GeV luminosity, lattice, quadrupole, optics 764
 
  • F. Plassard, A. Latina, E. Marín, D. Schulte, R. Tomás
    CERN, Geneva, Switzerland
  • P. Bambade
    LAL, Orsay, France
  
  In the framework of the CLIC rebaselining, the Beam Delivery System (BDS) have been re-optimized for its initial stage at 380 GeV. Two BDS designs with L*=4.3 meters and L*=6 meters have been investigated. The optimization of the lattices and the beam parameters at the interaction point (IP) have been performed by taking into account their energy upgrade to 3 TeV and the tuning feasibility of the BDS in presence of static imperfections.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK100  
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MOPIK124 A New Method to Tune the Nonlinear Lattice Online lattice, betatron, focusing, injection 828
 
  • W. Guo, Y. Hidaka, X. Yang
    BNL, Upton, Long Island, New York, USA
  
  Most nonlinear lattice tuning methods use only part of the optimization constraints, for example, part of the driving terms, nonlinear detuning, lifetime or injection efficiency. Even though some of the nonlinear properties can be improved, it is not guaranteed the nonlinear lattice is fully optimized. In this paper we propose to optimize the nonlinear lattice by correcting the betatron phase advance and detuning of the off-orbit lattices. It is shown that all the leading order optimization constraints are restored in this approach. One advantage of this new method is that the measurement is independent of BPM calibration errors. We succeed in both simulation and experiment in identifying the intentionally added sextupole errors.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK124  
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TUOCB1 Progress in the Design of Beam Optics for FCC-ee Collider Ring* quadrupole, collider, optics, emittance 1281
 
  • K. Oide, K. Ohmi
    KEK, Ibaraki, Japan
  • M. Benedikt, H. Burkhardt, B.J. Holzer, A. Milanese, J. Wenninger, F. Zimmermann
    CERN, Geneva, Switzerland
  • A.P. Blondel, M. Koratzinos
    DPNC, Genève, Switzerland
  • A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  • M. Boscolo
    INFN/LNF, Frascati (Roma), Italy
  
  The beam optics for the FCC-ee collider has been updated: (a) the layout is adjusted to a new footprint of FCC-hh, (b) the design around the interaction point is refined considering a number of machine-detecor interface issues, (c) the arc lattice is refined taking realistic magnet designs into account, (d) the β* and betatron tunes are re-optimized according to recent results of the beam-beam simulations, and more. These changes make the collider design more realistic without performance degradation.  
slides icon Slides TUOCB1 [4.891 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOCB1  
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TUPAB037 An Optimized Lattice for a Very Large Acceptance Compact Storage Ring lattice, storage-ring, laser, electron 1402
 
  • A.I. Papash, E. Bründermann, A.-S. Müller
    KIT, Eggenstein-Leopoldshafen, Germany
  
  Combining a circular storage ring and a laser wakefield accelerator (LWFA) might be the basis for future compact light sources and advancing user facilities to different commercial applications. Meanwhile the post-LWFA beam is not directly suitable for storage and accumulation in conventional storage rings. New generation rings with adapted features are required. Different geometries and ring lattices of very large-acceptance compact storage ring operating between 50 to 500 MeV energy range were studied. The main objective was to create a model suitable to store the post-LWFA beam with a wide momentum spread (2% to3%) and ultra-short electron bunches of fs range. The DBA-FDF lattice with relaxed settings, split elements and optimized parameters allows to open the dynamic aperture up to 20 mm while dispersion is limited and sextupole strength is high. The proposed machine model could be a basis for further, more detailed design studies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB037  
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TUPAB099 Status of MAX IV Linac Beam Commissioning and Performance linac, gun, storage-ring, injection 1547
 
  • S. Thorin, J. Andersson, M. Brandin, F. Curbis, L. Isaksson, M. Kotur, D. Kumbaro, F. Lindau, E. Mansten, D. Olsson, R. Svärd, S. Werin
    MAX IV Laboratory, Lund University, Lund, Sweden
  • J. Björklund Svensson
    Lund University, Division of Atomic Physics, Lund, Sweden
  
  The MAX IV linac is used both for full energy injection into two storage rings at 3 GeV and 1.5 GeV, and as a high brightness driver for a Short Pulse Facility (SPF). The linac has also been designed to handle the high demands of an FEL injector. The linac is now routinely injecting into the two storage rings, and commissioning work is focused towards delivering high brightness pulses to the SPF. In this paper we present results from characterisation of the linac in ring injection mode, as well as results from measurements of key parameters for the SPF such as bunch length and emittance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB099  
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TUPIK099 Beam-Based Alignment for the Rebaselining of CLIC RTML emittance, coupling, quadrupole, alignment 1939
 
  • Y. Han, L. Ma
    SDU, Shandong, People's Republic of China
  • A. Latina, D. Schulte
    CERN, Geneva, Switzerland
  
  The first stage of the CLIC is proposed to be at 380 GeV. So the Ring To Main Linac (RTML), which transport the beams from the damping ring to main linac with minimal emittance growth, should be restudied due to the new beam properties. In this paper the two bunch compressors in the RTML are redesigned. Then a complete study of the static beam-based alignment techniques along RTML is presented. The beam-based correction includes one-to-one and dispersion-free steering, then a global correction using tuning bumps is applied to reduce the final emittance and mitigate the effects of coupling. The results showed that the emittance growth budgets can be met both in the horizontal and vertical planes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK099  
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TUPIK113 Performance of the Fast Orbit Feedback System with the Double-Double Bend Achromat Installed in Diamond Light Source storage-ring, feedback, controls, vacuum 1989
 
  • S. Gayadeen, G. Rehm
    DLS, Oxfordshire, United Kingdom
  
  At Diamond Light Source, the Double-Double Bend Achromat (DDBA) lattice upgrade involved the conversion of one cell of the storage ring from a double bend achromat (DBA) structure to a double-DBA (DDBA). The new cell includes corrector magnets that are different in design to the DBA corrector magnets. The DDBA vacuum chamber cross section is also different from the DBA cells and includes both stainless steel and copper sections over which corrector magnets are fitted. The performance of the Fast Orbit Feedback (FOFB) used for electron beam stabilisation with the DDBA cell installed is presented in this paper. Firstly the different corrector magnet dynamic responses are characterised and secondly the closed loop performance of the FOFB is measured and analysed for the upgraded lattice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK113  
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TUPVA002 Updates on the Optics of the Future Hadron-Hadron Collider FCC-hh quadrupole, dipole, optics, hadron 2023
 
  • A. Chancé, D. Boutin, B. Dalena
    CEA/IRFU, Gif-sur-Yvette, France
  • B.J. Holzer, A. Langner, D. Schulte
    CERN, Geneva, Switzerland
  
  Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union's Horizon 2020 research and innovation programme under grant No 654305.
The FCC-hh (Future Hadron-Hadron Circular Collider) is one of the three options considered for the next generation accelerator in high-energy physics as recommended by the European Strategy Group. The layout of FCC-hh has been optimized to a more compact design following recommendations from civil engineering aspects. The updates on the first order and second order optics of the ring will be shown for collisions at the required centre-of-mass energy of 100 TeV. Special emphasis is put on the dispersion suppressors and general beam cleaning sections as well as first considerations of injection and extraction sections. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA002  
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TUPVA042 K-Modulation Developments via Simultaneous Beam Based Alignment in the LHC quadrupole, optics, closed-orbit, simulation 2159
 
  • L. van Riesen-Haupt, A. Seryi
    JAI, Oxford, United Kingdom
  • J.M. Coello de Portugal, E. Fol, R. Tomás, R. Tomás
    CERN, Geneva, Switzerland
  
  Funding: EuroCirCol
A parasitic effect of k-modulation is that if the modulated quadrupole has an offset the modulation results in a dipole like kick forcing the beam on a new orbit. This paper presents a new method using the orthonormality of singular value decomposition that uses this new orbit to estimate the offset. This could be used to measure misalignments or crossing angles but could also help improve k-modulation \beta measurements by predicting the parasitic tune change caused by the new orbit not passing through the centre of the sextupoles. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA042  
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TUPVA084 Quasi-Frozen Spin Concept of Deuteron Storage Ring as an Instrument to Search for the Electric Dipole Moment lattice, dipole, experiment, cavity 2275
 
  • V. Senichev, A.E. Aksentyev
    FZJ, Jülich, Germany
  • A.E. Aksentyev
    MEPhI, Moscow, Russia
  • S.N. Andrianov, A.N. Ivanov
    St. Petersburg State University, St. Petersburg, Russia
  • M. Berz, E. Valetov
    MSU, East Lansing, Michigan, USA
  • S. Chekmenev, J. Pretz
    RWTH, Aachen, Germany
  
  One of the possible arguments for the breaking of CP invariance is the existence of non-vanishing electric dipole moments (EDM) of elementary particles. Currently, the Jülich Electric Dipole Moment Investigation (JEDI) collaboration works under the conceptual design of the ring specifically for search of the deuteron electrical dipole moment (dEDM). The proposed Quasi-Frozen Spin concept differs from the Frozen Spin concept in that the spin of the reference particle is alternately deflected by a few degrees in different directions relative to momentum in the electric and magnetic parts of the ring. The QFS concept will allow using the existing COSY ring as pilot facility. The paper presents conceptual approach to ring design based on results of a study of spin decoherence and systematic errors, as well as the sensitivity estimation of the method to the determination of EDM.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA084  
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WEOAA3 Realizing a High-Intensity Low-Emittance Beam in the J-PARC 3-GeV RCS emittance, injection, resonance, extraction 2470
 
  • H. Hotchi, H. Harada, S. Kato, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The J-PARC 3-GeV rapid cycling synchrotron (RCS) has two functions; one as a proton driver to produce pulsed muons and neutrons, and the other as an injector to the following 50-GeV main ring (MR). RCS is now intensively developing a high-intensity beam test to realize a high-intensity low-emittance beam with less beam halo required from MR. This paper presents the recent experimental results, together with detailed discussions for the emittance growth and its mitigation mechanisms.  
slides icon Slides WEOAA3 [1.732 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOAA3  
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WEOAB1 Hénon-Heiles Single Particle Dynamics at IOTA lattice, experiment, synchrotron, electron 2508
 
  • S. A. Antipov
    University of Chicago, Chicago, Illinois, USA
  • S. Nagaitsev
    Fermilab, Batavia, Illinois, USA
  
  A Hénon-Heiles system is a simple, classical nonlinear Hamiltonian system offering a wide range of particle dynamics from regular orbits to resonant behavior to chaotic trajectories. Initially proposed to describe the motion of stars around a galactic center, it remains a vivid topic in Dynamics and Mathematical Physics since its discovery in 1964. Although the system and its modifications have been extensively studied numerically, its dynamics has never been observed in a controlled experiment. In this report we show that it is possible to create the Hénon-Heiles Hamiltonian using sextupoles in a realistic accelerator lattice. We propose a special sextupole channel to create the desired potential at the IOTA ring and study the 3D single particle dynamics by frequency map analysis and Poincare cross-sections. The proposed experiment would allow real world testing of regular and chaotic motion with a controlled strength of the nonlinearity.  
slides icon Slides WEOAB1 [4.685 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOAB1  
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WEOAB2 Correction of Beta-Beating Due to Beam-Beam for the LHC and Its Impact on Dynamic Aperture optics, quadrupole, dynamic-aperture, luminosity 2512
 
  • L.E. Medina Medrano, J. Barranco García, X. Buffat, Y. Papaphilippou, T. Pieloni, R. Tomás
    CERN, Geneva, Switzerland
  • J. Barranco García, T. Pieloni
    EPFL, Lausanne, Switzerland
  • L.E. Medina Medrano
    UGTO, Leon, Mexico
  
  Funding: This work is supported by the European Circular Energy-Frontier Collider Study, H2020 programme under grant agreement no. 654305, by the Swiss State Secretariat for Education, Research and Innovation SERI, and by the Beam project (CONACYT, Mexico).
Minimization of the beta-beating at the two main interaction points of the LHC arising from the head-on and long-range beam-beam interactions can be performed by adjusting the strength of quadrupole or sextupole correctors. This compensation scheme is applied to the current LHC optics where the results show a significant reduction of the peak and RMS beta-beating; and the impact on the dynamic aperture is computed. A proposal for a similar strategy to be adopted in the High Luminosity LHC is also discussed. 		 
slides icon Slides WEOAB2 [6.292 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOAB2  
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WEPAB006 Performance Improvements of the BESSY II Storage Ring by Optimizing the Phase Acceptance injection, resonance, storage-ring, optics 2571
 
  • P. Kuske, J. Li
    HZB, Berlin, Germany
  
  Linear optics modifications in order to improve injec-tion efficiency and for the installation of two IDs in one straight section demand an optimization of the sextupole correction scheme. Four harmonic sextupole families were sufficient with the earlier 8-fold symmetric lattice. Today there are ten families of harmonic sextupole mag-nets in addition to the three families of chromatic sextu-poles. This paper describes our experimental approach to find better settings for these harmonic sextupoles based on the direct optimization of the injection efficiency with a longitudinal phase offset between storage ring and the injector - in our case a booster synchrotron. As demon-strated in the paper, the resulting improvement of the phase acceptance of the ring leads to increased momen-tum acceptance by suppressing 3rd order non-systematic resonances. This increases not only the injection effi-ciency for long bunches but also the Touschek lifetime, the largest contribution to the overall lifetime of low emittance storage rings.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB006  
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WEPAB011 High Order Magnetic Field Components and Non-Linear Optics at the ANKA Storage Ring wiggler, octupole, resonance, betatron 2586
 
  • A.I. Papash, E. Blomley, J. Gethmann, E. Huttel, A.-S. Müller, M. Schuh
    KIT, Eggenstein-Leopoldshafen, Germany
  
  The Karlsruhe Institute of technology operates the 2.5 GeV electron storage ring ANKA as an accelerator test facility and synchrotron radiation source. A superconducting wiggler is installed in a short straight section of the ring where vertical beta-function is large (13 m). The life time of the electron beam was reduced from 15 to 12 hours at a high field level of the wiggler (2.5 T) even though the coherent shift of vertical tune was compensated locally. Computer simulations show the non-linear nature of the effect. The ANKA storage ring operates with strong sextupoles at a positive chromaticity of +2/+6. Even residual octupole components of the wiggler field, set at the tolerance limit of fabrication conditions, could reduce the dynamic aperture for off-momentum particles providing the betatron tune is located in the vicinity of a weak octupole resonance and the chromaticity is high. Also the vertical betatron tune is close to the sextupole resonance Qy=8/3. Large resonance stop-band and proximity of sextupole resonance affect the life time as well. Betatron tunes of ANKA have been shifted away of suspected high-order resonances and beam life time was essentially improved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB011  
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WEPAB050 Commissioning of SESAME Storage Ring storage-ring, injection, optics, kicker 2694
 
  • M. Attal, A.A. Abbadi, I.A. Abid, T.H. Abu-Hanieh, A. Al-Dalleh, H. Al-Mohammad, M.A. Al-Najdawi, D.S. Foudeh, A. Hamad, E. Huttel, A. Ismail, S.Kh. Jafar, K. Manukyan, I. Saleh, N.Kh. Sawai, M.M. Shehab
    SESAME, Allan, Jordan
  
  SESAME light source uses a 2.5GeV storage ring, designed to produce synchrotron light in the hard X-ray region. The 133.2 m circumference ring composed of 16 Double Bend Achromat cells with 16 dispersive straight sections, offers a maximum capacity of 25 beamlines. The storage ring is filled with electrons using an 800MeV injector of 1 Hz repetition rate. This article reports on the main results and first experience of storage ring commissioning and operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB050  
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WEPAB053 Candidate Lattice Design of the HEPS Booster Consisting of Combined-Function Dipoles dipole, lattice, emittance, booster 2700
 
  • Y. Jiao, Y.M. Peng, G. Xu
    IHEP, Beijing, People's Republic of China
  
  Funding: Work supported by NSFC (11475202, 11405187)
The High Energy Photon Source (HEPS) is a 6-GeV, ultralow-emittance, kilometer-scale storage ring light source to be built in China. It is planned to use a 300 MeV linac and a full energy booster as the injector. In this paper we present one of the candidate lattice designs for the HEPS booster, where most of the dipoles are combined with quadrupole and sextupole gradients. Global optimization of the lattice has been done, where the dependencies of the lattice performance on various parameters, including the minimum pole face field, damping partition number, number of dipoles, etc. are discussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB053  
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WEPAB055 Characterizing the Nonlinear Performance of a DLSR With the Effective Acceptance of the Bare Lattice lattice, resonance, storage-ring, emittance 2706
 
  • Y. Jiao, Z. Duan, G. Xu
    IHEP, Beijing, People's Republic of China
  
  Funding: Work supported by NSFC (11475202, 11405187, 11605212)
In a diffraction-limited storage ring (DLSR) light source, associated with the strong focusing and sextu-poles, the detuning terms are large and integer and half integer resonances can be reached at small momentum deviation and transverse amplitudes. We propose to use the effective ring acceptances of the bare lattice to characterize the nonlinear performance of the actual ring, by considering the limiting effects of integer and half integer resonances on beam dynamics. Such a concept will be very useful in lattice design of a DLSR light source. In this paper, we will discuss the reasoning, verification, and application range of this definition. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB055  
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WEPAB060 Design Study for the First Version of the HALS Lattice lattice, storage-ring, emittance, quadrupole 2713
 
  • Z.H. Bai, W. Li, L. Wang, P.H. Yang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  The Hefei Advanced Light Source (HALS) was proposed as a future soft X-ray diffraction-limited storage ring at NSRL. Recently the first version lattice of the HALS storage ring has been studied using a new lattice design concept that we proposed for diffraction-limited storage rings. In this new concept, the beta functions of each cell are made to be locally symmetric. In this paper, an 8BA lattice and a 6BA lattice are designed for the HALS with the first and the second kind of the new concept, respectively. In their nonlinear optimization, good dynamic aperture and momentum aperture can be easily obtained. Especially the dynamic momentum aperture can be larger than 7% or even 10%, which enables long beam lifetime and implementation of longitudinal injection scheme. The studied 6BA lattice is at present considered as the nominal HALS lattice of the first version.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB060  
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WEPAB069 Possible Suppression of Head-Tail Instability by a Feedback Kicker for a Light Source Without Any Sextupole storage-ring, emittance, dynamic-aperture, resonance 2738
 
  • T.-Y. Lee, B.H. Oh
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  As storage ring based light sources pursue as low emittance as possible down to the diffraction limited number by adopting as many bending magnets and quadrupoles in a cell, the number of sextupole magnets required to correct chromaticity and secure a sufficiently big dynamic aperture grows substantially. As a result, the circumference of a multi-bend achromatic lattice storage ring is typically very long. This paper discusses over a possible scheme to run a storage ring without sextupole magnets at all and suppress the head-tail instability by using a transverse feedback kicker.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB069  
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WEPAB114 Potential Performance Limit of Storage Rings emittance, storage-ring, quadrupole, optics 2836
 
  • X. Huang
    SLAC, Menlo Park, California, USA
  
  The next generation of storage ring light sources will have significantly higher performance as multi-bend achromat cell structures are made practical with strong quadrupole and sextupole magnets. In principle the natural emittance can be made ever smaller with stronger magnets and larger rings until it reaches the true diffraction limit for hard X-rays. By considering the scaling laws of linear optics and nonlinear beam dynamics of storage rings and technical challenges, we explore the potential performance limit of future storage rings. A similar discussion may be applicable to the limit of energy frontier heavy-ion storage ring colliders.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB114  
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WEPIK006 Cancellation of the Leak Field from Lambertson Septum for the Beam Abort System in the SuperKEKB quadrupole, coupling, emittance, septum 2918
 
  • N. Iida, M. Kikuchi, K. Kodama, T. Mimashi, T. Mori, Y. Ohnishi, K. Oide, H. Sugimoto, M. Tawada
    KEK, Ibaraki, Japan
  
  The first commissioning of SuperKEKB, Phase 1, was performed from February 2016 for five months. A Lambertson septum magnet is utilized to vertically extract the aborted beam, kicked by the horizontal abort kickers upstream into a beam dump. This magnet creates unexpected leak field with a non-negligible skew quadrupole component to the stored beam. Two kinds of skew quadrupole magnets are installed on both sides of the Lambertson septum. One is additional skew windings on the sextupole magnet, and the other is a skew quadrupole magnet with permanent magnets. This paper will report that the cancellations of the leak fields was successful and useful for optics correction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK006  
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WEPIK007 Optics Design and Observation for the Beam Abort System in SuperKEKB HER optics, injection, kicker, quadrupole 2922
 
  • N. Iida, K. Egawa, Y. Enomoto, Y. Funakoshi, M. Kikuchi, T. Mimashi, Y. Ohnishi, K. Oide, Y. Suetsugu
    KEK, Ibaraki, Japan
  
  In the first commissioning of SuperKEKB, which is 'Phase 1', the new abort system is tested in the High Energy Ring (HER). There is a risk that aborted beams with low emittance and high current may destroy the window for extraction from beam pipe. In order to enlarge the aborted beam at the window, quadrupole field is applied only for the aborted beam. In the Low Energy Ring (LER), quadrupole pulsed magnets will be installed to enlarge the aborted beam, and in the HER, a pair of identical sextupole magnets is installed between the abort kickers and the extraction window. These sextrupole magnets are connected by I or 'I transformation to cancel the geometrical nonlinearity for the stored beam in the ring. This paper will report the optics design for the abort system of the HER as well as the observation of the aborted beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK007  
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WEPIK012 Performance of SuperKEKB High Energy Ring Beam Abort System kicker, extraction, operation, power-supply 2939
 
  • T. Mimashi, Y. Enomoto, N. Iida, M. Kikuchi, K. Kodama, T. Mori, Y. Suetsugu
    KEK, Ibaraki, Japan
  • K. Abe
    Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan
  • K. Kise, A. Tokuchi
    Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan
  
  New Beam abort system was installed at the Super-KEKB High Energy Ring. It was designed to enlarge the horizontal beam size at the beam extraction window to protect the extraction window, and it also makes the beam abort gap shorter. It consists of four horizontal kicker magnets, one vertical kicker to sweep the beam position in vertical direction, sextupole magnet to enlarge the horizontal beam size, one lambertson magnet, Ti extraction window and beam dump. Four horizontal kicker magnets and one vertical kicker magnet connects to the one power supply. The ceramic chambers cooled by the water are inserted in each kicker coils. The Abort system had been used during SuperKEKB phase 1 operation. This paper describes the performance of the abort system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK012  
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WEPIK017 100 km CEPC Parameters and Lattice Design luminosity, collider, dynamic-aperture, optics 2958
 
  • D. Wang, T.J. Bian, X. Cui, J. Gao, H. Geng, Q. Qin, B. Sha, N. Wang, Y. Wang, C.H. Yu, J.Y. Zhai, C. Zhang, Y. Zhang
    IHEP, Beijing, People's Republic of China
  • F. Su
    Institute of High Energy Physics (IHEP), People's Republic of China
  
  The 100km double ring configuration with shared su-perconducting RF system has been defined as baseline by the circular electron positron collider (CEPC) steering committee. Based on this new scheme, we will get higher luminosity for Higgs (+170%) keeping the beam power in preliminary conceptual design report (Pre-CDR) or to reduce the beam power (19 MW) while keeping same luminosity. CEPC will be compatible with W and Z ex-periment. The luminosity for Z is designed at the level of 1035 cm-2s−1. The requirement for the energy acceptance of Higgs has been reduced to 1.5% by enlarging the ring to 100 km. The optics of arc and final focus system (FFS) with crab sextupoles has been designed, and also some primary dynamic aperture (DA) results were introduced.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK017  
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WEPIK018 Optics Design for Cepc Double Ring Scheme lattice, interaction-region, optics, emittance 2962
 
  • Y. Wang, T.J. Bian, J. Gao, H. Geng, B. Sha, D. Wang, C.H. Yu, Y. Zhang
    IHEP, Beijing, People's Republic of China
  • F. Su
    Institute of High Energy Physics (IHEP), People's Republic of China
  
  CEPC is a future Circular Electron and Positron Collider proposed by China to mainly study the Higgs boson. Its baseline scheme is double ring scheme and alternative scheme is partial double ring scheme. This paper will present the optics design for the main ring of double ring scheme. CEPC will also work as W and Z factories. Compatible optics design for W and Z mode will be presented as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK018  
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WEPIK041 Update on the JLEIC Electron Collider Ring Design electron, emittance, lattice, ion 3018
 
  • Y.M. Nosochkov, Y. Cai, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • Y.S. Derbenev, F. Lin, V.S. Morozov, F.C. Pilat, G.H. Wei, Y. Zhang
    JLab, Newport News, Virginia, USA
  • M.-H. Wang
    Self Employment, Private address, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under US DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported by the US DOE Contract DE-AC02-76SF00515.
We present an update on the lattice design of the electron ring of the Jefferson Lab Electron-Ion Collider (JLEIC). The electron and ion collider rings feature a unique figure-8 layout providing optimal conditions for preservation of beam polarization. The rings include two arcs and two intersecting long straight sections containing a low-beta interaction region (IR) with special optics for detector polarimetry, electron beam spin rotator sections, ion beam cooling sections, and RF-cavity sections. Recent development of the electron ring lattice has been focused on minimizing the beam emittance while providing an efficient non-linear chromaticity correction and large dynamic aperture. We describe and compare three lattice designs, from which we determine the best option. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK041  
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WEPIK057 Transverse Resonance Island Buckets as Bunch Separation Scheme injection, optics, simulation, operation 3059
 
  • P. Goslawski, A. Jankowiak, F. Kramer, M. Ries, M. Ruprecht, G. Wüstefeld
    HZB, Berlin, Germany
  
  Funding: Supported by the BMBF
Beam storage close to a tune resonance (Qx = 1/3,1/4) can generate transverse resonance island buckets in the x,x' phase space providing a second stable island orbit winding around the standard orbit. The two orbits are well separated, with good life time and stability. Successful user experiments have been conducted at BESSY II and the Metrology Light Source (MLS) *,** with such an operation mode. We discuss the required beam optics setup, the TopUp injection process and present successful measurements taken at photon beamlines at BESSY II.
* THPMR017, P.Goslawski et al., IPAC2016, Busan, Korea
** MOPWA021, M.Ries et al., IPAC2015, Richmond, USA 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK057  
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WEPIK065 Research Activities Towards a Conversion of PETRA III Into a Diffraction Limited Synchrotron Light Source lattice, emittance, synchrotron, photon 3077
 
  • R. Wanzenberg, I.V. Agapov, K. Balewski, M. Bieler, W. Brefeld, R. Brinkmann, M. Dohlus, H. Ehrlichmann, X.N. Gavaldà, J. Keil, M. Körfer, G.K. Sahoo, C.G. Schroer, E. Weckert
    DESY, Hamburg, Germany
  • M. Eriksson
    MAX IV Laboratory, Lund University, Lund, Sweden
  
  At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. Research activities have been started towards a future upgrade scenario of PETRA III which envisions the conversion of the PETRA ring into a ultra-low emittance hard X-ray radiation source: PETRA IV. The lattice design is aiming for a horizontal emittance in the range between 10 pm rad and 30 pm rad at a beam energy of 6 GeV. Two different approaches have been considered for the lattice design: a design based on a hybrid multibend achromat with an interleaved sextupole configuration based on the ESRF design, and a lattice with a non-interleaved sextupole configuration with a special phase space exchange configuration. We are reporting the current status of the design activities including studies related to the injector.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK065  
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WEPIK070 Nonlinear Lattice Optimization for the SPring-8 Upgrade lattice, betatron, injection, octupole 3091
 
  • K. Soutome, H. Tanaka
    RIKEN SPring-8 Center, Hyogo, Japan
  • Y. Shimosaki, M. Takao
    JASRI/SPring-8, Hyogo-ken, Japan
  
  The SPring-8 upgrade project has adopted the hybrid MBA lattice to achieve the emittance of about 100 pmrad at 6 GeV with damping effects by insertion devices. This optics has two dispersion bumps in one unit cell where chromaticity-correcting sextupoles locate. The horizontal and vertical betatron phases between these bumps are tuned to be 3PI and PI, respectively, to cancel the low order contributions of nonlinear kicks due to sextupoles. However, it is not easy to obtain a sufficiently large dynamic aperture (DA) since (i) the cancellation is incomplete due to a nested arrangement, (ii) sextupoles are very strong, and (iii) the number of tuning knobs is limited. The DA is quite small due to the leakage of nonlinear kicks by nested sextupoles. We hence proposed to install additional weak sextupoles between the dispersion bumps to suppress the leakage kick further. Simulations show that this simple scheme is very effective for suppressing ADTS and for enlarging DA. We present details of this scheme and some numerical examples together with a newly developed fourth-order formula of ADTS for describing and controlling the lattice nonlinearity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK070  
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WEPIK084 Approximating Nonlinear Forces with Phase-Space Decoupling simulation, octupole, proton, linac 3120
 
  • B.T. Folsom, E. Laface
    ESS, Lund, Sweden
  
  Beam tracking software for accelerators typically falls into two categories: fast envelope simulations limited to linear beam optics, and slower multiparticle simulations that can model nonlinear effects. To find a middle ground between these approaches, we introduce virtual coordinates in position and momentum which have a cross-dependency (i.e. p*=f(x) where x is an initial position and p* is a virtual projection of momentum onto the position axis).This technique approximates multiparticle simulations with a significant reduction in calculation cost.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK084  
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WEPIK097 An Optimization Tool to Design a Coreless Non-Linear Injection Kicker Magnet injection, kicker, emittance, target 3170
 
  • B. MacDonald-de Neeve
    ETH, Zurich, Switzerland
  • B. MacDonald-de Neeve, M. Paraliev, A. Saá Hernández
    PSI, Villigen PSI, Switzerland
  
  Top-up injection into low emittance light sources is challenging due to their inherent small dynamic apertures (DA). The use of a multipole-magnet injection kicker prevents disturbing the circulating beam. However, the injected bunch will be mismatched due to unwanted focusing (linear field profile) or even filamented (nonlinear field profile). Coreless nonlinear kicker magnets, using different configurations of straight conductors, can produce transverse step-like magnetic field distribution which prevent the mismatch. We explored an 8-conductor configuration and a multi-conductor approach like unipolar massless septum design. Maximizing the spatial derivative of the transverse field step function is crucial in order to kick the injected bunch inside the DA. Comparing the results of different designs a particular dependence between the smallest clear aperture and the maximum transverse field spatial derivative was observed. We have developed an optimization tool to generate arbitrary 2D magnetic fields and determine the associated current distribution. With it we obtained new design solutions for possible injection magnets that go beyond the limitations of the standard designs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK097  
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WEPIK101 Novel Implementation of Quadrupole and Higher Order Fringe Fields to Accelerator Design quadrupole, multipole, dipole, space-charge 3184
 
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Until recently, in the initial design phase of any accelerator project, it was not possible to have an adequate description of quadrupole and higher order multipole fringe fields. We report on the latest developments in analytical fringe fields for multipoles, particularly for quadrupoles and sextupoles. We show how they can be used to improve accelerator codes and make them both faster and more precise. We also show how the analytical formulae for the fringe fields yield expressions for both the scalar and vector potentials in electromagnetism. We conclude by discussing the application of both potentials to the design of multipole magnets as well as the implementation of symplectic kick approximations for fringe fields in thin lens models that could be used in accelerator codes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK101  
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WEPIK116 Aberration Compensation in a Skew Parametric-Resonance Ionization Cooling Channel multipole, resonance, damping, simulation 3221
 
  • A.V. Sy, Y.S. Derbenev, V.S. Morozov
    JLab, Newport News, Virginia, USA
  • A. Afanasev
    GWU, Washington, USA
  • Y. Bao
    UCR, Riverside, California, USA
  • R.P. Johnson
    Muons, Inc, Illinois, USA
  
  Funding: This work was supported in part by U.S. DOE STTR Grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Skew Parametric-resonance Ionization Cooling (Skew PIC) represents a novel method for focusing of highly divergent particle beams, as in the final 6D cooling stage of a high-luminosity muon collider. In the muon collider concept, the resultant equilibrium transverse emittances from cooling with Skew PIC are an order of magnitude smaller than in conventional ionization cooling. The concept makes use of coupling of the transverse dynamic behavior, and the linear dynamics are well-behaved with good agreement between analytic solutions and simulation results. Compared to the uncoupled system, coupling of the transverse dynamic behavior purports to reduce the number of multipoles required for aberration compensation while also avoiding unwanted resonances. Aberration compensation is more complicated in the coupled case, especially in the high-luminosity muon collider application where equilibrium angular spreads in the cooling channel are on the order of 200 mrad. We present recent progress on aberration compensation for control of highly divergent muon beams in the coupled correlated optics channel, and a simple cooling model to test the transverse acceptance of the channel. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK116  
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WEPIK122 Applying Square Matrix to Optimize Storage Ring Nonlinear Lattice lattice, resonance, dynamic-aperture, storage-ring 3241
 
  • Y. Li, L. Yu
    BNL, Upton, Long Island, New York, USA
  
  Funding: Supported by US DOE Contract No. DE-AC02-98CH10886 and DE-SC0012704.
A new method of using linear algebra technique to analyze periodical nonlinear beam dynamics is presented. For a given dynamical system, a square upper triangular transfer matrix is constructed out of a one turn Taylor transfer map. First we separate the matrix into different low dimensional invariant subspaces according to their eigenvalues. Then a stable Jordan transformation can be obtained on each subspace. The transformation provides an excellent action-angle approximation to the solution of the nonlinear dynamics. And the deviation of the new action from constancy provides a measure of the nonlinearity of the motions, which provides a novel method to optimize the nonlinear dynamic system. We applied this method to optimize various rings, such as NSLS-II, SPEAR3, and APS-U lattice, the promising dynamic aperture have been achieved from both tracking simulation and experimental measurements. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK122  
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THXA1 Beam-Based Optimization of Storage Ring Nonlinear Beam Dynamics dynamic-aperture, injection, storage-ring, resonance 3627
 
  • X. Huang, J.A. Safranek
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported in part by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
This paper will present considerations and algorithms for direct online optimization of the nonlinear beam dynamics of existing and future storage rings. The experimental setup and results from using this approach to improve the dynamic aperture of the SPEAR3 storage ring, using the robust conjugate direction search method and the particle swarm optimization method, will be covered. 		 
slides icon Slides THXA1 [1.589 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THXA1  
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THPAB008 Particle Swarm Optimization Algorithm Applied in Online Commissioning at the MLS and BESSY II injection, storage-ring, simulation, dynamic-aperture 3700
 
  • J. Li, J. Feikes, P. Goslawski, M. Ries
    HZB, Berlin, Germany
  
  Particle Swarm Optimization (PSO) is a population based optimization technique inspired by the social behaviour of bird flocking. This algorithm has been successfully used for beam dynamics simulation due to its excellent capability to deal with large-dimensional optimization problems. At the MLS and BESSY II PSO was first successfully applied to improve the lifetime by 20~30% within only 10 iterations respectively. Now the PSO has been implemented as a multifunctional online optimizer to improve the machine performance. This paper presents some results of online experiments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB008  
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THPAB049 Progress in the Understanding of the Performance Limitations in the CERN Low Energy Ion Ring resonance, ion, optics, space-charge 3819
 
  • A. Huschauer, H. Bartosik, S. Hancock, V. Kain
    CERN, Geneva, Switzerland
  
  The performance of heavy ion beams in the CERN Low Energy Ion Ring is mainly limited by beam loss occuring during the radio-frequency capture and the first part of acceleration. Since October 2015, the driving mechanism of these losses has been studied in detail and an interplay of direct space charge forces and excited betatron resonances was identified as the most plausible explanation of the phenomenon. In this paper we summarize the current understanding of the loss mechanism by presenting recent experimental and simulation studies. We discuss strategies to mitigate beam loss and further improve the performance of the accelerator in the future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB049  
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THPAB151 Online Optimisation Applications at SPS injection, coupling, storage-ring, quadrupole 4086
 
  • T. Pulampong, P. Klysubun, S. Kongtawong, S. Krainara, P. Sudmuang
    SLRI, Nakhon Ratchasima, Thailand
  
  Optimisation of a particle accelerator with very limited diagnostic system is proved to be very challenging and complicated. Theoretical calculation and perfect machine model never guarantee the best solution in the actual machine. In this work, optimisation of injection system from Low energy Beam Transport line (LBT) to Siam Photon Source (SPS) storage ring and reduction of beam coupling employing Robust Conjugate Direction Search (RCDS) algorithm are demonstrated. New record improvement on injection efficiency and better coupling control will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB151  
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THPIK012 The Magnets of BERLinPro: Specification, Design, Measurement and Quality Analysis dipole, multipole, quadrupole, operation 4124
 
  • A.N. Matveenko, M. Abo-Bakr, K.B. Bürkmann-Gehrlein
    HZB, Berlin, Germany
  • I.V. Davidyuk, O.A. Shevchenko, A.V. Utkin, N.A. Vinokurov
    BINP SB RAS, Novosibirsk, Russia
  
  Funding: Work supported by grants of Helmholtz Association VH-NG-636 and HRJRG-214
A total of 77 magnets form the magnetic lattice of the BERLinPro energy recovery linac prototype: 1+8+8 dipole magnets of three different types, 12+40 quadrupole magnets of two different types and 8 sextupole magnets have been produced by BINP. After the design phase, magnets production started in 2015, measurements and delivery took place in 2016, first assembly stage was finished in 03/2017. The motivation for the magnet specification and a summary of the basic design is given in this paper. Select-ed measurement data from the final acceptance tests are presented and analysed to ensure the magnet quality. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK012  
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THPIK027 Dynamic Behaviour of Fast-Pulsed Quadrupole Magnets for LINAC4 Transfer Line quadrupole, linac, flattop, target 4150
 
  • S. Kasaei
    IPM, Tehran, Iran
  • M.C.L. Buzio, L. Fiscarelli
    CERN, Geneva, Switzerland
  
  Linac4, recently built at CERN, is a linear normal conducting accelerator for negative hydrogen ions (H−). A new transfer line will link Linac4 to the Proton Synchrotron Booster. This transfer line includes 21 quadrupole magnets characterized by fast excitation cycles, which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on rotating and fixed search coils. We show how these instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour of these quadrupoles, such as the impact of hysteresis and dynamic eddy current effects.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK027  
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THPVA019 Self-consistent Space Charge Tracking Method based on Lie Transform space-charge, simulation, proton, emittance 4454
 
  • E. Laface, J. F. Esteban Müller
    ESS, Lund, Sweden
  
  In this paper we propose to describe the self-force of a particles beam, known as space charge, as an Hamiltonan term dependent on the distribution of the particles' coordinates: Hsc = Hsc(ρ(x,y,z)). This Hamiltonian is then used, together with the kinetic component Hk in a Lie transform to generate a transport map by e-L:Hk +Hsc: where the Lie operator :Hk + Hsc: is defined according to the Dragt's notation [1]. Then the Lie transform is used to transport directly the distribution function ρ(x, y, z) in a self-consistent iterative algorithm. The result of this proof-of-concept idea is verified on a drift space and on a FODO channel and compared with a traditional multi-particles simulation code.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA019  
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THPVA026 Practical Stabilisation of Transverse Collective Instabilities with Second Order Chromaticity in the LHC simulation, octupole, damping, impedance 4477
 
  • M. Schenk, D. Amorim, N. Biancacci, X. Buffat, L.R. Carver, R. De Maria, K.S.B. Li, E. Métral, B. Salvant
    CERN, Geneva, Switzerland
  
  The study reports on dedicated measurements made with a single nominal bunch in the LHC at 6.5 TeV. First, we show that a significant amount of second order chromaticity Q'' can be introduced in the machine in a well-controlled manner. Second, we demonstrate that the incoherent betatron tune spread from Q'' can provide beam stability through the Landau damping mechanism. This is a first step in the development of a Q'' knob to be potentially applied during regular physics operation in the LHC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA026  
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THPVA032 Space-Charge Simulation of Integrable Rapid Cycling Synchrotron lattice, space-charge, optics, resonance 4501
 
  • J.S. Eldred, A. Valishev
    Fermilab, Batavia, Illinois, USA
  
  Integrable optics is an innovation in particle accelerator design that enables strong nonlinear focusing without generating parametric resonances. We use a Synergia space-charge simulation to investigate the application of integrable optics to a high-intensity hadron ring that could replace the Fermilab Booster. We find that incorporating integrability into the design suppresses the beam halo generated by a mismatched KV beam. Our integrable rapid cycling synchrotron (iRCS) design includes other features of modern ring design such as low momentum compaction factor and harmonically canceling sextupoles. Experimental tests of high-intensity beams in integrable lattices will take place over the next several years at the Fermilab Integrable Optics Test Accelerator (IOTA) and the University of Maryland Electron Ring (UMER).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA032  
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THPVA048 Design and Progress on Mechanical & Alignment System for HEPS-TF alignment, controls, quadrupole, emittance 4544
 
  • C. H. Li, S.J. Li, J. Liu, H. Wang, X.L. Wang, Z. Wang, L. Wu
    IHEP, Beijing, People's Republic of China
  
  HEPS is a new generation synchrotron facility with a stringent requirement of very low emmittance. The key technology difficulties are supposed be overcome during the HEPS-TF stage. There are two projects in progress for mechanical and alignment system. One is the development of precision auto-tuning magnet girder, to meet the requirement of beam based alignment in tunnel, the other is the study on vibrating-wire alignment technique to improve alignment accuracy of magnets on a girder. This paper will describe the design and progress of both projects.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA048  
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THPVA052 Preliminary Design of Magnet Support System for CEPC booster, dipole, collider, quadrupole 4557
 
  • H. Wang, H. Qu, J.L. Wang, Z. Wang, N. Zhou
    IHEP, Beijing, People's Republic of China
  
  Magnet support system is important for CEPC. For the 100 km design of CEPC, there will be thousands of mag-nets and their supports in both collider and booster. Espe-cially, the booster ring is above the collider in the space, the magnets are hung by the supports. The goals of mag-net supports are simple and flexible structure, minimizing the magnet deformation, good stability, low cost and so on. This paper will describe the preliminary design of magnet support system, the optimization to minimize the magnet deformation and the topology optimization of the frame structure in booster.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA052  
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