Keyword: dynamic-aperture
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MOPGW012 Study of Fringe Fields Effects from Final Focus Quadrupoles on Beam Based Measured Quantities quadrupole, multipole, optics, simulation 90
 
  • T. Pugnat, B. Dalena
    CEA-IRFU, Gif-sur-Yvette, France
  • L. Bonaventura, A. Simona
    Politecnico di Milano, Milano, Italy
  • R. De Maria, V.K.B. Olsen
    CERN, Geneva, Switzerland
 
  Accelerator physics needs advanced modeling and simulation techniques, in particular for beam stability studies. A deeper understanding of the effects of magnetic fields non-linearities will greatly help in the improvement of future colliders design and performance. In *, a new tracking method was proposed to study the effect of the longitudinal dependency of the harmonics on the beam dynamics. In this paper, the study will focus on the effects on observable quantities in beam based measurements, for the case of HL-LHC Inner Triplet and with possible tests in LHC.
* T. Pugnat et al., "Accurate and Efficient Tracking in Electromagnetic Quadrupoles", in Proc. IPAC’18, Vancouver, Canada, June 2018, paper THPAK004, pp. 3207.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW012  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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MOPGW021 Symplectic Tracking for the Robinson Wiggler wiggler, storage-ring, electron, linear-dynamics 120
 
  • J. Li, J. Feikes, T. Mertens, Y. Petenev, M. Ries, A. Schälicke
    HZB, Berlin, Germany
 
  A Robinson wiggler (RW) is considered to be installed in the Metrology Light Source (MLS) to lengthen the bunch and improve the Touschek lifetime by manipulating the damping partitions. Symplectic tracking is crucial to study the impact of the nonlinear field components introduced by the Robinson wiggler. This paper introduces a tracking method based on an implicit symplectic integrator to solve the exact Hamiltonian equations of particle motion in the wiggler. In addition, a numerical generating function method is implemented as an approach to realize fast tracking.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW021  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPGW045 A Fast Method for Multi-Objective Nonlinear Dynamics Optimization of a Storage Ring SRF, storage-ring, lattice, sextupole 190
 
  • J.J. Tan, Z.H. Bai, W. Li, L. Wang, P.H. Yang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  Multi-objective evolutionary algorithms (MOEAs), including multi-objective genetic algorithm and particle swarm optimization algorithm, have been widely applied in the nonlinear dynamics optimization of storage ring light sources. In the optimization, the direct tracking of objectives, which are, for example, dynamic aperture (DA) and momentum aperture, is very time-consuming. We noticed that there is some positive correlation between on- and off-momentum nonlinear dynamics performances, which can be used to reduce the computation time when applying MOEAs. In this paper, a fast method is proposed, in which a strategy is introduced to speed up the process of optimizing nonlinear dynamics using MOEAs. Taking the SSRF storage ring as an example, on- and off-momentum DAs are optimized using MOEAs with and without the fast strategy, and then a comparison is made to demonstrate the fast method.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW045  
About • paper received ※ 15 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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MOPGW051 Diffusion Map Analysis in High Energy Storage Ring Based e+/e Collider radiation, synchrotron-radiation, collider, synchrotron 203
 
  • J. Wu, Q. Qin, Y. Zhang
    IHEP, Beijing, People’s Republic of China
  • J. Wu, Y. Zhang
    University of Chinese Academy of Sciences, Beijing, People’s Republic of China
 
  Funding: Project 11775238 supported by NSFC
In a very high energy e+/e storage ring collider, e.g. Circular Electron Positron Collider (CEPC), the dynamic aperture is limited by the strong synchrotron radiation especially in the vertical direction. Some tracking results also shows that the beam lifetime does not correspond well to the dynamic aperture. Here we develop a method called diffusion map analysis, aiming to describe the beam distribution diffusion in transverse amplitude space by tracking less turns. The diffusion may come from quantum fluctuation of SR, beamstrahlung effect and nonlinearity. Comparing cases with different configuration of sextupoles, the diffusion map analysis presents good consistency with beam lifetime that needs much more turns of tracking. Constraints based on the diffusion map is applied to our dynamic aperture optimization, which could help us achieve enough long beam lifetime.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW051  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPGW053 Residual Gas Lifetime In High Energy Photon Source (HEPS) scattering, electron, vacuum, photon 210
 
  • S.K. Tian, H.S. Xu
    IHEP, Beijing, People’s Republic of China
 
  High vacuum has always been mandatory in particle accelerators. This is especially true for circular machines, where the beam makes thousands or millions turns, and beam lifetime is heavily affected by the residual gas scattering. At the beginning of storage ring operation the lifetime was very short mostly dominated by residual gas scattering. The residual gas lifetime is comprised of the elastic and inelastic scattering on electrons and elastic and inelastic scattering on nuclei. One usually calculates only the elastic scattering on nuclei (single Coulomb scattering) and inelastic scattering on nuclei (bremsstrahlung) of the residual gas scattering lifetime component. The analytic calculation the residual gas scattering lifetime and simulations of the beam interaction with the residual gas with code will be shown in this presentation  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW053  
About • paper received ※ 15 May 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019  
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MOPGW115 A Cross-Cell Interleaved Nonlinear Lattice for Potential NSLS-II Upgrade lattice, emittance, sextupole, optics 393
 
  • Y. Li, A. He, B.N. Kosciuk, T.V. Shaftan, V.V. Smaluk
    BNL, Upton, Long Island, New York, USA
  • Z.H. Bai, L. Wang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  An interleaved sextupole scheme using cross-cell betatron phase cancellation technique is adopted as a candidate for the future NSLS-II upgrade lattice. The lattice uses as many NSLS-II installed magnets as possible, including 30 dipoles, to compose a triple bend achromat lattice. A 300 pm.rad horizontal beam emittance is achieved. The emittance can be further reduced to around 200 pm rad with damping wigglers. Various design concepts used in modern 4th-generation light sources, such as adopting longitudinal gradient dipoles and anti-bend scheme, are incorporated into the design as well. The betatron phase-advance between sextupoles is designed to have a cross-cell interleaving cancellation pattern in the transverse planes. The dynamic aperture is big enough for the conventional off-axis top-off injection. At the same time, a large energy acceptance looks promising to ensure a sufficiently long beam lifetime.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW115  
About • paper received ※ 12 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPMP023 Dynamic Aperture at Injection Energy for the HE-LHC dipole, injection, lattice, collider 480
 
  • M. Hofer, M. Giovannozzi, J. Keintzel, R. Tomás, F. Zimmermann
    CERN, Geneva, Switzerland
  • L. van Riesen-Haupt
    JAI, Oxford, United Kingdom
 
  As part of the Future Circular Collider study, the High Energy LHC (HE-LHC) is a proposed hadron collider situated in the already existing LHC tunnel. It aims at achieving a center of mass energy of 27 TeV, almost doubling the design c.o.m. energy of the LHC. This increase in energy relies on the use of 16 T Nb3Sn dipoles to be developed for the FCC-hh. The field quality of these dipoles is expected to have a big impact on the Dynamic Aperture (DA) at injection energy and subsequently tracking studies are conducted to evaluate the impact of magnetic field errors on the beam dynamics. In the following the results of these studies for the different injection energies considered for the HE-LHC are presented and a possible strategy for increasing the DA are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP023  
About • paper received ※ 06 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPMP039 Developments in the Experimental Interaction Regions of the High Energy LHC dipole, luminosity, beam-beam-effects, shielding 532
 
  • L. van Riesen-Haupt, J.L. Abelleira
    University of Oxford, Oxford, United Kingdom
  • J.L. Abelleira, E. Cruz Alaniz
    JAI, Oxford, United Kingdom
  • J. Barranco García, T. Pieloni, C. Tambasco
    EPFL, Lausanne, Switzerland
  • M. Hofer, J. Keintzel, R. Tomás, F. Zimmermann
    CERN, Geneva, Switzerland
 
  Funding: Work supported by the Swiss institute for Accelerator Research and Technology , CHART.
The High Energy LHC (HE-LHC) aims to collide 13.5 TeV protons in two high luminosity experiments and two low luminosity experiments. In the following, the recent updates in the two high luminosity experimental interaction regions (EIR) of the HE-LHC will be illustrated. These EIR aim to focus the beams to a β* of 0.45 m at the interaction point (IP) to achieve a lifetime integrated luminosity of 10 ab-1. On top of the triplet optics designed to achieve this, it will present energy deposition driven separation dipole designs, optics solutions for the matching section and dispersion suppressors as well as studies involving the integration into the lattice options. In particular it will outline geometric considerations, spurious dispersion suppression as well as results from dynamic aperture studies.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP039  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS038 BEAM DYNAMICS OF HIGH CHROMATICITY LATTICE FOR IRANIAN LIGHT SOURCE FACILITY (ILSF) STORAGE RING storage-ring, lattice, resonance, optics 943
 
  • F. Foroughi, S.M. Jazayeri
    IUST, Narmac, Tehran, Iran
  • E. Ahmadi, S. Dastan, J. Rahighi
    ILSF, Tehran, Iran
 
  One of the limiting factors of electron beam lifetime in low emittance storage rings is Head-Tail (HT) insta-bility. Low emittance storage rings typically have a large negative natural chromaticity due to the strong quadru-poles. Above transition large negative natural chroma-ticity leads to large Head-Tail instability which limit the beam lifetime. Since the threshold current of HT insta-bility is directly related to linear chromaticity, increasing the linear chromaticity to slightly positive value is a solution to prevent HT instability. In this paper we in-creased the chromaticity of Iranian Light Source Facility (ILSF) to (+4, +4) and we will investigate the beam dy-namics of ILSF 3GeV storage ring in high chromaticity. For reaching this aim we have used two families of sex-tupoles for chromaticity correction and then optimized them to maximize the dynamic aperture and Touschek lifetime. The beam dynamics of high chromaticity lattice is presented in this paper.
Foroughi.farangis@gmail.com
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS038  
About • paper received ※ 29 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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TUPGW070 Multi-Bend Achromat Lattice Design for the Future of TPS Upgrade lattice, emittance, dipole, storage-ring 1564
 
  • M.-S. Chiu, P.J. Chou, J.C. Huang
    NSRRC, Hsinchu, Taiwan
  • S.-Y. Lee
    Indiana University, Bloomington, Indiana, USA
 
  We present a TPS upgrade option with the hybrid 7BA (H7BA) lattice. We also derive a simple formula on optimal dipole angle distribution among H7BA dipoles. The agreement is satisfactory. We also report preliminary results on the dynamic aperture (DA) optimization. Possible improvement on H7BA lattice is outlined.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW070  
About • paper received ※ 24 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW071 Optimization and Measurements on the Double Mini-Betay Lattice in the TPS Storage Ring lattice, betatron, injection, storage-ring 1567
 
  • M.-S. Chiu, B.Y. Chen, C.H. Chen, J.Y. Chen, Y.-S. Cheng, P.C. Chiu, P.J. Chou, T.W. Hsu, K.H. Hu, J.C. Huang, P.Y. Huang, C.-C. Kuo, T.Y. Lee, C.Y. Liao, W.Y. Lin, Y.-C. Liu, H.-J. Tsai, F.H. Tseng
    NSRRC, Hsinchu, Taiwan
 
  The Taiwan Photon Source (TPS) is capable of operat-ing in multi-bunch and single-bunch mode. To operate in a hybrid mode as requested by users, we developed a lattice with chromaticities of 0.8/2 (x/y) to provide higher single bunch currents. Beam dynamics simulations and lattice characterizations including dynamic aperture, frequency map analysis, tune shift with energy, tune shift with amplitude, and betatron coupling will be discussed in this report.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW071  
About • paper received ※ 30 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW075 Towards a Diffraction Limited Storage Ring lattice, storage-ring, optics, emittance 1573
 
  • J. Bengtsson
    DLS, Oxfordshire, United Kingdom
  • P.F. Tavares
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  A Lattice for a 500 m circ. Tunnel, based on First Principles & Best Practices is presented. Background: MAX-IV has made a "quantum leap" towards a Diffraction Limited Storage Ring (DLSR) by an Engineering-Science, i.e., Systems, Approach; leading to a Paradigm Shift(s): e.g. the Magnet Reference Radius is a Key Parameter, a Design Choice, that must be considered at an early stage for Robust Design. In addition, the pursuit of Systematic Benchmarks, MAX-I -> MAX-IV, has enabled the pursuit of Disruptive Technologies with Predictable Results. For example: Combined-Function Magnets (built-to-print) enabling an "IKEA Approach" (innovative, prompted by low-budget) like the use of Concrete Girders, Vacuum Requirements mitigated by NEG Coating, and Solid State Modulators providing a Reliable Injector by a Full-Energy Linac. Since "The Experiment" now has been done, Permanent Magnets, well understood for high-end Insertion Devices, provides another opportunity/step for a Next Generation. Besides, the Electricity Bill for Conventional Magnets is a significant part of the Operations Cost.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW075  
About • paper received ※ 20 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPGW079 Exploratory Lattice Design Studies for Diamond-II lattice, controls, emittance, optics 1589
 
  • B. Singh, R. Bartolini, J. Bengtsson, H. Ghasem, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  We pursue Robust Design of a Ring-Based Synchrotron Light Source as a System. In particular, the Design Phi-losophy is based on: ’ To Control the Nonlinear Dynamics: Control the Linear Optics. In particular, by: ’ Optimal Control of Natural Chromaticity. ’ ’-I Transformer’ between Chromatic Sextupoles for Unit Cell. ’ Higher-Order-Achromat for Super Period. In addition, by pushing the Requirements for Robust & Efficient Injection ’Upstream’, i.e., by considering On-Axis Injection, and by utilizing Reverse Bends (to trans-cend the reductionist Theoretical Minimum Emittance Cell), either: ’ the Natural Emittance can be reduced further, ’ or the Touschek Lifetime can be improved. Bottom line, a Design Choice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW079  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP018 A Novel Non-Linear Strip-Line Kicker Driven by Fast Pulser in Common Mode kicker, injection, impedance, multipole 2345
 
  • J. Chen, Z. Duan, L. Huo, Y. Li, H. Shi, G. Wang, L. Wang, N. Wang
    IHEP, Beijing, People’s Republic of China
 
  The next generation storage ring-based light sources adopt multi-bend achromat lattices to achieve a low emittance. The dynamic apertures of these machines are usually less than 10 mm so that the traditional pulsed local bump injection is difficult to achieve. Off-axis injection with a pulsed multipole or a non-linear kicker could be a viable solution which requires a moderate dynamic aperture of a few mm. In this paper, a novel non-linear kicker design is presented. Unlike pulsed sextupole or nonlinear kicker magnet, the nonlinear kicker we proposed is a traveling wave kicker with 2 strip-line electrodes driven by a nanosecond-level fast pulser in common mode. The disturbance to the stored beam is minimal since the perturbation is limited to the target bunch alone.
Work support by NSFC(11475200 and 11675194).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP018  
About • paper received ※ 30 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS053 Frequency Map Measurements at the TPS resonance, operation, MMI, storage-ring 3240
 
  • C.H. Chen, B.Y. Chen, J.Y. Chen, M.-S. Chiu, P.J. Chou, T.W. Hsu, B.Y. Huang, C.-C. Kuo, W.Y. Lin, Y.-C. Liu, H.-J. Tsai, F.H. Tseng
    NSRRC, Hsinchu, Taiwan
 
  Taiwan Photon Source (TPS) has been operated for several years since it’s first light in December 2014. TPS has achieved reliable routine operation at 500 mA with more than 10 hrs beam lifetime. The dynamic aperture measurements and associated Frequency Map Analyses (FMA) at TPS reveal the beam dynamics behavior with and without insertion devices. A preliminary measurement study by using the turn-by-turn BPMs and comparison with the model simulation results will be presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS053  
About • paper received ※ 30 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS078 Chaos Indicators for Studying Dynamic Aperture in the IOTA Ring with Protons space-charge, lattice, simulation, betatron 3301
 
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
 
  The Integrable Optics Test Accelerator (IOTA) is a novel storage ring under commissioning at Fermi National Accelerator Laboratory designed (in part) to investigate the dynamics of beams in the presence of highly nonlinear transverse focusing fields that generate integrable single-particle motion. In this study, we explore the sensitivity of the lattice dynamic aperture to the presence of nonlinear space charge. For this purpose, two distinct chaos indicators are compared (frequency map analysis and forward-backward integration). Because the integrability of motion requires integer betatron tune advance between passes through the nonlinear magnetic element, a large role is played by space-charge-induced tune spread. As a result, these tools are also applied to a toy model of the IOTA lattice to investigate the sensitivity of dynamic aperture to violations of the integer tune advance condition.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS078  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS103 Optimization of a Low-Alpha Lattice for the HLS-II Storage Ring lattice, storage-ring, quadrupole, sextupole 3360
 
  • S.W. Wang, Y.G. Wang, W. Xu, K. Xuan
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  • J.Y. Li
    IHEP, Beijing, People’s Republic of China
 
  To generate terahertz radiation at HLS-II, a low-alpha lattice scheme is proposed. The new lattice can reduce the bunch length in the storage ring, thus enhancing the coherent synchrotron radiation in the THz region. In this paper, the design and optimization of a low-alpha lattice is reported. The new lattice preserves the symmetry of nominal lattice and reduces the first and second order momentum factor at the cost of increasing maximum beta function and natural emittance. The bunch length is tracked and the result shows that the low-alpha lattice can effectively compress bunches in the storage ring. The performance of this low-alpha lattice can be further studied and improved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS103  
About • paper received ※ 29 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB099 Applications of Dimension-Reduction to Various Accelerator Physics Problems kicker, sextupole, synchrotron, storage-ring 4060
 
  • W.F. Bergan, I.V. Bazarov, C.J.R. Duncan, D. L. Rubin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: DE-SC 0013571 DGE-1650441 OIA-1549132
Particle accelerators contain hundreds of magnets, making dimension-reduction techniques attractive when attempting to tune them. We apply this procedure to two different problems: correcting the orbit in the Cornell synchrotron and maximizing the dynamic aperture in the Cornell Electron Storage Ring (CESR). Cornell’s rapid cycling synchrotron accepts a 200 MeV beam from the linac and accelerates it to 6 GeV for injection into the CESR. ‘Kicker coils’ (dipole correctors) are used to correct for residual fields which would otherwise cause beam loss at the low energies. In such cases, it is usually advisable to measure and correct the orbit. However, one cannot measure the orbit without first getting the beam to circulate a few hundred times, by which point the low-energy orbit would already be mostly corrected. In order to speed up the process of empirical orbit tuning, we form knobs which have the largest effect on the global orbit error, so that the dimensionality of the space which must be searched may be greatly reduced. A small dynamic aperture in CESR will have adverse effects on beam lifetime and injection efficiency, and so ought to be maximized by tuning sextupoles. However, it is often unclear which sextupoles one ought to tune to alleviate the problem. Moreover, once the chromaticity is properly adjusted, it should not be changed. Since we expect resonance driving terms (RDTs) to have a large impact on the dynamic aperture, we develop sextupole knobs which change the RDTs as much as possible while leaving the chromaticity fixed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB099  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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