Keyword: dynamic-aperture
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MOOCB02 A Lattice Correction Approach through Betatron Phase Advance lattice, sextupole, simulation, betatron 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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MOPOW050 Study of Lower Horizontal Emittance Optics in the Present Soleil Storage Ring emittance, quadrupole, lattice, optics 827
 
  • H.C. Chao, P. Brunelle, A. Nadji, L.S. Nadolski, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  
  With the aim of delivering a lower horizontal emittance beam to the users of the present SOLEIL ring, a systematic lattice study is carried out. The goal is to discover feasible optics solutions having the horizontal emittance notably lower than the present value of 3.9 nm rad, while fulfilling all the physical requirements and without changing the current magnet structure in the lattice. The strategy adopted is a cell-wise optimization of the linear lattices in the two types of double-bend cells that constitute the SOLEIL ring. In the second step they are concatenated via finer matching. A global scan of the 5 quadrupole families for the search of stable solutions is performed. The statistical properties are given. One can easily select possible solutions without matching. For the second type of cell having 10 quadrupole families, another scan of quadrupoles and a matching using a quadrupole triplet are applied for linear optics characteristics. Finally, the nonlinear optimization is performed with modern nonlinear optimization algorithms.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW050  
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MOPOY002 Towards Beam-Dynamics Simulations Including More Realistic Field Descriptions for the HESR multipole, quadrupole, lattice, dipole 847
 
  • J.H. Hetzel, U. Bechstedt, J. Böker, A. Lehrach, B. Lorentz, R. Tölle
    FZJ, Jülich, Germany
  
  The High Energy Storage Ring (HESR) is part of the upcoming Facility for Antiproton and Ion Research (FAIR) placed in Darmstadt (Germany). The HESR is designed for antiprotons with a momentum range from 1.5 GeV/c to 15 GeV/c, but will as well be suitable to provide heavy ion beams with a momentum range from approximately 0.6 GeV/c to 5.8 GeV/c. To guarantee smooth operation it is crucial to verify and improve the design with beam-dynamics simulations. Particularly the dynamic aperture is calculated as a measure of quality. Complementary to previous beam dynamics calculations based on frequency map analysis*, the dynamic aperture is calculated using a variant of the Lyapunov exponent. The first bending and focusing magnets have been delivered and the magnetic fields measured recently. So the modeled assumptions regarding the multipole imperfections of these elements are now replaced by values based on measurements. This contribution contains the inclusion of the measured values as well as the the tracking-based dynamic aperture calculations.
* D.M. Welsch, A. Lehrach, B. Lorentz, R.Maier, D. Prasuhn, R.Tölle: "Investigation and Optimization of Transverse Non-Linear Beam Dynamics in the High-Energy Storage Ring HESR"; IPAC'10 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY002  
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TUOBA03 Application of Differential Evolution Algorithm in Future Collider Optimization sextupole, lattice, collider, emittance 1025
 
  • Y. Zhang
    IHEP, Beijing, People's Republic of China
  • D. Zhou
    KEK, Ibaraki, Japan
  
  Funding: Project U1332108 supported by NSFC.
The dynamic aperture of is very limited due to the very small beta at IP in the SuperKEKB. In the storage ring based Higgs factory, the vertical beta function is not so small, but the much larger circumference enlarge the detuning term especially in horizontal direction. It is very hard to optimize the dynamic aperture in the future colliders. The particle loss may comes from different cause for different energy or different transverse coupling. The design of CEPC is still in process. The construction of SuperKEKB is nearly finished, but there still exist some problem which could reduce the performance. There are a few hundred parameters to be varied in the future colliders. The global optimization may be a good way to enlarge the dynamic aperture. Differential Evolution is a very simple population based, stochastic function minimizer which is very powerful at the same time. In this paper we show some application of the algorithm in the two machines. It has the potential to help us optimize the machine. 		 
slides icon Slides TUOBA03 [2.289 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBA03  
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TUPMW007 Impact of Long Range Beam-Beam Effects on Intensity and Luminosity Lifetimes from the 2015 LHC Run luminosity, emittance, experiment, hadron 1422
 
  • M.P. Crouch, R.B. Appleby
    UMAN, Manchester, United Kingdom
  • D. Banfi, C. Tambasco
    EPFL, Lausanne, Switzerland
  • J. Barranco, R. Bruce, X. Buffat, T. Pieloni, M. Pojer, B. Salvachua, G. Trad
    CERN, Geneva, Switzerland
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Research supported by the High Luminosity LHC project
Luminosity is one of the key parameters that determines the performance of colliding beams in the Large Hadron Collider (LHC). Luminosity can therefore be used to quantify the impact of beam-beam interactions on the beam lifetimes and emittances. The High Luminosity Large Hadron Collider (HL-LHC) project aims to reach higher luminosities, approximately a factor of 7 larger than the nominal LHC at peak luminosity without crab cavities. Higher luminosities are achieved by increasing the bunch populations and reducing the transverse beam sizes. This results in stronger beam-beam effects. Here the LHC luminosity and beam intensity decay rates are analysed as a function of reducing beam separation with the aim of characterising the impact of beam-beam effects on the luminosity and beam lifetime. The analysis and results are discussed with possible application to the HL-LHC upgrade. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW007  
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TUPMW019 First Evaluation of Dynamic Aperture at Injection for FCC-hh dipole, injection, target, simulation 1466
 
  • B. Dalena, D. Boutin, A. Chancé, J. Payet
    CEA/IRFU, Gif-sur-Yvette, France
  • B.J. Holzer, R. Martin, D. Schulte
    CERN, Geneva, Switzerland
  
  Funding: This Research and Innovation Action project submitted to call H2020-INFRADEV-1-2014-1 receives funding from the European Union's H2020 Framework Programme under grant agreement no. 654305.
In the hadron machine option, proposed in the context of the Future Circular Colliders (FCC) study, the dipole field quality is expected to play an important role, as in the LHC. A preliminary evaluation of the field quality of dipoles, based on the Nb3Sn technology, has been provided by the magnet group. The effect of these field imperfections on the dynamic aperture, using the present lattice design, is presented and first tolerances on the main multipole components are evaluated. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW019  
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TUPMW040 Beam-beam Simulation for the 2015 RHIC Proton Run with Electron Lenses proton, electron, lattice, simulation 1533
 
  • Y. Luo, W. Fischer, X. Gu, G. Robert-Demolaize, V. Schoefer
    BNL, Upton, Long Island, New York, USA
  • S.M. White
    ESRF, Grenoble, France
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Electron lenses were used for head-on beam-beam compensation for the first time in the 2015 Relativistic Heavy Ion Collider (RHIC) 100~GeV polarized proton run. Lattices with the achromatic telescopic squeeze (ATS) scheme of β* are adopted to improve the off-momentum dynamic aperture. The phase advances between the electron lenses to one of the two collisional points are set to kπ to minimize the beam-beam resonance driving terms. In this article, we present the results from weak-strong and strong-strong beam-beam simulations with head-on beam-beam compensations for these lattices. Simulations are also carried out aiming to explain the observations from operation. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW040  
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TUPOR030 Design of Octupole Channel for Integrable Optics Test Accelerator octupole, optics, simulation, electron 1731
 
  • S. A. Antipov
    University of Chicago, Chicago, Illinois, USA
  • K. Carlson, A. Valishev, S.J. Wesseln
    Fermilab, Batavia, Illinois, USA
  • R. Castellotti
    SSSUP, Pisa, Italy
  
  We present the design of octupole channel for Integrable Optics Test Accelerator (IOTA). IOTA is a test accelerator at Fermilab, aimed to conduct research towards high-intensity machines. One of the goals of the project is to demonstrate high nonlinear betatron tune shifts while retaining large dynamic aperture in a realistic accelerator design. At the first stage the tune shift will be attained with a special channel of octupoles, which creates a variable octupole potential over a 1.8 m length. The channel consists of 18 identical air-cooled octupole magnets. The magnets feature a simple low-cost design, while meeting the requirements on maximum gradient - up to 1.4 kG/cm3, and field quality - strength of harmonics below 1%. Numerical simulations show that the channel is capable of producing a nonlinear tune shift of 0.08 without restriction of dynamic aperture of the ring.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR030  
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WEPMW003 NONLINEAR OPTIMIZATION OF CLIC DRS NEW DESIGN WITH VARIABLE BENDS AND HIGH FIELD WIGGLERS dipole, damping, emittance, sextupole 2416
 
  • H. Ghasem, J. Alabau-Gonzalvo, F. Antoniou, S. Papadopoulou, Y. Papaphilippou
    CERN, Geneva, Switzerland
  
  The new design of CLIC damping rings is based on longitudinal variable bends and high field superconducting wiggler magnets. It provides an ultra-low horizontal normalised emittance of 412 nm-rad at 2.86 GeV. In this paper, nonlinear beam dynamics of the new design of the damping ring (DR) with trapezium field profile bending magnets have been investigated in detail. Effects of the misalignment errors have been studied in the closed orbit and dynamic aperture.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW003  
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WEPMW026 Beam-Beam Simulation With Crab-Cavities for Erhic proton, electron, luminosity, cavity 2479
 
  • Y. Luo, Y. Hao, Y.C. Jing, V. Ptitsyn, D. Trbojevic
    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.
To avoid the luminosity loss due to cross-angle collision, crab cavities are being considered for the electron-ion collider designs at Brookhaven National Laboratory. In this article, we study the effects of crab cavities on the proton beam dynamics without and with beam-beam interactions. Dynamic apertures are to be calculated with various parameters of crab cavities. To minimize the distortion from a single crab cavity, harmonic crab cavities are also considered. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW026  
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WEPOW006 Hybrid Multi Bend Achromat at 3 GeV for Future 4th Generation Light Sources lattice, emittance, sextupole, dipole 2822
 
  • S.M. Liuzzo, D. Einfeld, L. Farvacque, P. Raimondi
    ESRF, Grenoble, France
  
  Starting from the Hybrid Multi Bend Achromat (HMBA) lattice designed for the 6GeV ESRF-EBS we rescale the lattice energy to 3GeV and optimize the lattice parameters to achieve dynamic apertures sufficient for injection and lifetimes of more than 7h without errors. The rescaling results to an emittance of roughly 140pmrad. Further optimizations of bending magnets longitudinal gradient, optics and sextupole fields show the possibility to further decrease emittance and increase the DA and lifetime. A comparison with other lattice designs is also presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW006  
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WEPOW021 The Low Emittance Reconstruction of the Arc Section of the Photon Factory emittance, photon, sextupole, lattice 2874
 
  • K. Harada, Y. Kobayashi, N. Nakamura, K. Oide, H. Sakai, S. Sakanaka
    KEK, Ibaraki, Japan
  
  The present horizontal emittance of the Photon Factory (PF) ring is about 35.4 nmrad. By the reconstruction of the normal cells at the arc section, the emittance can be reduced to about 8 nmrad. The double number of the combined function short bending magnets are adopted and one present normal cell become two new normal cells. Although the lattice of the straight sections are not changed, the optics are optimized to reduce the non-linear effects of the sextupoles of the arc sections. By keeping the tune advance of the straight section as 3 for the horizontal direction and 2.5 for the vertical, the dynamic aperture as large as that of the present ring can be achieved with the magnetic errors. The difference of the optics of the straight sections are so little that the beam injection and the operation of the in-vacuum short-gap undulators can be maintained. The hardware design will be began as the next step for the realization of the plan. In this proceedings, the design, optimization and simulation results for the low emittance lattice are shown.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW021  
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WEPOW049 Physics Design Progress towards a Diffraction Limited Upgrade of the ALS emittance, lattice, injection, brightness 2956
 
  • C. Steier, J.M. Byrd, S. De Santis, H. Nishimura, D. Robin, F. Sannibale, C. Sun, M. Venturini, W. Wan
    LBNL, Berkeley, California, USA
  
  Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231.
Improvements in brightness and coherent flux of more than two orders of magnitude are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source. We will describe the progress in the physics design of this upgrade, including lattice evolution, error tolerance studies, simulations of collective effects, and intra beam scattering. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW049  
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WEPOY053 Comparison of Tracking Codes for the Determination of Dynamic Aperture in Storage Rings dipole, lattice, storage-ring, experiment 3114
 
  • R. Hipple, M. Berz
    MSU, East Lansing, Michigan, USA
  
  Funding: This work is supported by the U.S. Department of Energy under grant number DE-FG02-08ER41546
Currently there is a great deal of activity towards making precision measurements utilizing storage rings, for example the Muon g-2 experiment at Fermilab, and the Electric Dipole Moment (EDM) program of the JEDI Collaboration. These experiments are intended to perform measurements requiring sub-ppm precision. Of utmost importance in this regard is the ability of tracking codes to treat all nonlinear effects arising from the detailed field distributions present in the system, not the least of which are fringe fields. In previously published work,*,**, we performed parallel tests of various tracking codes in order to compare and contrast the results. In this study, we continue this line of research and extend the scope to parallel-faced dipoles and electrostatic dipoles.
* R.Hipple, M. Berz, Microscopy and Microanalysis 21 Suppl. 4 (2015)
** R. Hipple, M.Berz, MODBC3, ICAP 2015, in press.
 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY053  
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THOBA01 RF Pinger Commissioning and Beam Dynamics Studies at NSLS-II cavity, synchrotron, LLRF, controls 3161
 
  • G.M. Wang, B. Holub, Y. Li, J. Rose, T.V. Shaftan, V.V. Smaluk
    BNL, Upton, Long Island, New York, USA
  
  Funding: DOE contract DE-SC0012704
NSLS II storage ring RF system has the digital ramp control function, enabling rapid change of the cavity phase and amplitude. This, together with largely overcoupled RF cavity and transmitter geometry, enables the possibility to "ping" the beam in longitudinal phase space. Similar to the pinger commonly used for transverse beam dynamic studies, the RF jump presents with a powerful tool for investigation of the machine longitudinal beam dynamics. During our beam studies, RF phase was jumped within a short interval of time (less than synchrotron period). Using turn-by-turn data from BPMs we measured the machine energy acceptance with and without damping wigglers. This paper presents the beam study results. 		 
slides icon Slides THOBA01 [4.365 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THOBA01  
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THPMB035 A Comparative Study of Low Energy Compact Storage Rings for a Thomson Scattering X-ray Source storage-ring, scattering, lattice, emittance 3308
 
  • L. Ovchinnikova, V.I. Shvedunov
    SINP MSU, Moscow, Russia
  • E.G. Bessonov, M.V. Gorbunkov
    LPI, Moscow, Russia
  • A.A. Mikhailichenko
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V.I. Shvedunov
    LEA MSU, Moscow, Russia
  
  A low-energy (<50 MeV) compact storage ring is a basic component of an X-ray source with high average flux based on Thomson scattering. Such ring provides electron bunches with ~1 nC charge and repetition rate up to 100 MHz for interaction with intense laser pulses. Such ring should provide a small (tens of microns rms) beam radius at interaction point, must have large dynamic aperture, sufficient space for allocation of different elements, such as laser resonator, RF cavity, fast beam injection/extraction systems, beam pick-ups and correctors. In this report, we present the results of comparative study of four versions of storage ring with different structure of lattices.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB035  
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THPMR012 Optimization of Nonlinear Dynamics for Sirius lattice, sextupole, optics, betatron 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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THPMR035 Low Horizontal Beta Optics for ALBA lattice, optics, sextupole, emittance 3461
 
  • G. Benedetti, J. Campmany, Z. Martí
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  
  The ALBA insertion device beamlines have a horizontal and vertical rms source size of 130 and 5.5 microns. Protein crystallography beamlines (Xaloc) would benefit from a reduction of the horizontal and increase of the vertical beam size, to gain spatial resolution and avoid anisotropy effects. A modified lattice with horizontal and vertical beam size of 74 and 9 microns has been setup and tested, breaking the ring symmetry, with different setting of the six neightbouring quadrupoles at each side of the Xaloc insertion device. Such configuration keeps the nominal emittance almost unvaried and the working point is recovered by small changes in the quadrupole strengths of the four symmetric matching sections. A dedicated setting of the nine available sextupole families has been obtained by numerical optimization of the dynamical apertures and tune shifts. The lattice settings have been satisfactorily tested. The measured lifetime is reduced a factor two and the injection efficiency decreases to 60%. Finally, the option of increasing the number of sextupole families, to recover the dynamic aperture and guarantee the injection efficiency, has been studied.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR035  
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THPMR037 Observations of Resonance Driving Terms in the LHC during Runs I and II resonance, dipole, injection, betatron 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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THPMR038 Non-Linear Errors in the Experimental Insertions of the LHC insertion, multipole, coupling, dipole 3472
 
  • E.H. Maclean, F.S. Carlier, M. Giovannozzi, A. Langner, S. Mönig, T. Persson, P.K. Skowroński, R. Tomás
    CERN, Geneva, Switzerland
  
  Correction of nonlinear magnetic errors in low-β insertions can be of critical significance for the operation of a collider. This is expected to be of particular relevance to LHC Run II and the HL-LHC upgrade, as well as to future colliders such as the FCC. Current correction strategies for these accelerators have assumed it will be possible to calculate optimized local corrections through the insertions using a magnetic model of the errors. To test this assumption the nonlinear errors in the LHC experimental insertions have been examined via feed-down and amplitude detuning. It will be shown that while in some cases the magnetic measurements provide a sufficient description of the errors, in others large discrepancies exist which will require beam-based correction techniques.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR038  
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THPMR044 Short Term Dynamic Aperture with AC Dipoles dipole, resonance, simulation, operation 3496
 
  • S. Mönig, J.M. Coello de Portugal, A. Langner, E.H. Maclean, T. Persson, R. Tomás
    CERN, Geneva, Switzerland
  
  The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. This paper will report the results of studies of the effect of the AC dipole on the dynamic aperture.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR044  
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THPMR053 Influence of Magnet Multipole Field Components on Beam Dynamics in the JLEIC Ion Collider Ring multipole, ion, collider, dipole 3525
 
  • G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
    JLab, Newport News, Virginia, USA
  • Y. Nosochkov, M.-H. Wang
    SLAC, Menlo Park, California, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515.
To get a luminosity level of a few 1033 cm-2ses−1 at all design points of the Jefferson Lab Electron Ion Collider (JLEIC) project, small β* values in both horizontal and vertical planes are necessary at the Interaction Point (IP) in the ion collider ring. This also means large β in the final focus area, chromaticity correction sections, etc. which sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole field components of magnets are surveyed to find a possible compromise between the requirements and what can be realistically achieved by a magnet manufacturer. This paper describes that work. Moreover, non-linear field dedicated correctors are also studied to provide semi-local corrections of specific multipole field components. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR053  
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THPMR054 Error Correction for the JLEIC Ion Collider Ring quadrupole, closed-orbit, ion, collider 3528
 
  • G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
    JLab, Newport News, Virginia, USA
  • Y. Nosochkov, M.-H. Wang
    SLAC, Menlo Park, California, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515.
The sensitivity to misalignment, magnet strength error, and BPM noise is investigated in order to specify design tolerances for the ion collider ring of the Jefferson Lab Electron Ion Collider (JLEIC) project. Those errors, including horizontal, vertical, longitudinal displacement, roll error in transverse plane, strength error of main magnets (dipole, quadrupole, and sextupole), BPM noise, and strength jitter of correctors, cause closed orbit distortion, tune change, beta-beat, coupling, chromaticity problem, etc. These problems generally reduce the dynamic aperture at the Interaction Point (IP). According to real commissioning experiences in other machines, closed orbit correction, tune matching, beta-beat correction, decoupling, and chromaticity correction have been done in the study. Finally, we find that the dynamic aperture at the IP is restored. This paper describes that work. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR054  
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THPOR009 Cepc Partial Double Ring Lattice Design lattice, dipole, luminosity, factory 3785
 
  • F. Su
    Institute of High Energy Physics (IHEP), People's Republic of China
  • S. Bai, T.J. Bian, Z. Duan, J. Gao, H. Geng, D. Wang, Y. Wang, M. Xiao, G. Xu, Y. Zhang
    IHEP, Beijing, People's Republic of China
  
  In this paper, we introduced the layout and lattice design of Circular-Electron-Positron-Collider (CEPC) partial double ring (PDR) scheme. The baseline design of CEPC is a single beam-pipe electron positron collider, which has to adopt pretzel orbit scheme. And it is not suitable to serve as a high luminosity Z factory. If we choose partial double ring scheme, we can get a higher luminosity with lower power and be suitable to serve as a high luminosity Z factory. In this paper, we discussed the details of CEPC partial double ring lattice design and showed the dynamic aperture study and optimization.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR009  
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THPOR010 CEPC Parameter Choice and Partial Double Ring Design luminosity, sextupole, emittance, optics 3788
 
  • D. Wang, S. Bai, T.J. Bian, X. Cui, Z. Duan, J. Gao, H. Geng, Y.Y. Guo, Q. Qin, N. Wang, Y. Wang, M. Xiao, J.Y. Zhai, C. Zhang, Y. Zhang
    IHEP, Beijing, People's Republic of China
  • W. Chou
    Fermilab, Batavia, Illinois, USA
  • F. Su
    Institute of High Energy Physics (IHEP), People's Republic of China
  
  Funding: Work supported by the National Foundation of Natural Sciences (11505198 and 11575218)
In order to avoid the pretzel orbit, CEPC is proposed to use partial double ring scheme in CDR. Based on crab waist scheme, we hope to either increase the luminosity with same beam power as Pre-CDR, or reduce the beam power while keeping the same luminosity in Pre-CDR. FFS with crab sextupoles has been developed and the arc lattice was redesigned to acheive the lower emittance for crab waist scheme. 		 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR010  
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THPOR011 Design study of CEPC Alternating Magnetic Field Booster dipole, sextupole, emittance, booster 3791
 
  • T.J. Bian, S. Bai, X. Cui, J. Gao, D. Wang, Y. Wang, M. Xiao, C. Zhang
    IHEP, Beijing, People's Republic of China
  • Y. Cai
    SLAC, Menlo Park, California, USA
  • M. Koratzinos
    DPNC, Genève, Switzerland
  • F. Su
    Institute of High Energy Physics (IHEP), People's Republic of China
  
  CEPC is next generation circular collider proposed by China. The design of the full energy booster ring of the CEPC is especially challenging. The ejected beam energy is 120GeV but the injected beam only 6GeV. In a conventional approach, the low magnetic field of the main dipole magnets creates problems. We propose to operate the booster ring as a large wiggler at low beam energies and as a normal ring at high energies to avoid the problem of very low dipole magnet fields.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR011  
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THPOR012 Dynamic Aperture Study of the CEPC Main Ring with Interaction Region sextupole, interaction-region, optics, resonance 3795
 
  • Y. Wang, S. Bai, T.J. Bian, J. Gao, H. Geng, D. Wang, 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 Circular Electron and Positron Collider proposed by China to mainly study the Higgs boson. In order to achieve factory luminosity, a strong focusing system and low-emittance are required. A momentum acceptance as large as 2\% is also required to get a reasonable beam lifetime. This is one of the key issues of the CEPC accelerator physics. In this paper, the optics design of the interaction region and the optimization of dynamic aperture for the whole ring (single ring scheme) will be presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR012  
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THPOR013 Magnet Error Effect on Dynamic Aperture in CEPC multipole, quadrupole, sextupole, lattice 3798
 
  • S. Bai, J. Gao, Y. Wang, D.J. Xiao
    IHEP, Beijing, People's Republic of China
  
  With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 1034 cm-2s−1) is becoming more popular in the accelerator world. The CEPC project in China is one of them. The performance of the machine can be influenced by the existence of every kind of inaccuracies of the magnets, such as misalignment errors and field errors, multipole errors etc on. In this paper, we reported the errors that used in the CEPC beam dynamic study, and the influence on dynamic aperture of the CEPC main ring when introducing these kinds of errors.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR013  
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THPOR017 Dynamic Aperture Optimization at CEPC with Pretzel Orbit lattice, dipole, quadrupole, collider 3808
 
  • H. Geng, S. Bai, X. Cui, Z. Duan, J. Gao, Y.Y. Guo, Y.M. Peng, Q. Qin, D. Wang, N. Wang, Y. Wang, G. Xu, Y. Yue, Y. Zhang
    IHEP, Beijing, People's Republic of China
  • W. Chou
    Fermilab, Batavia, Illinois, USA
  • F. Su
    Institute of High Energy Physics (IHEP), People's Republic of China
  
  A preliminary design of the CEPC ring with pretzel orbit will be presented. The ring and pretzel orbit will be designed for 50 bunches, as required in the CEPC Pre-CDR. The linear optics, as well as the non-linear chromaticity compensation with the presence of pretzel orbit will be described. Different phase advance difference between the long and short straight sections, have been tried to optimize the dynamic aperture, the results will be shown in this paper.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR017  
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