MC5: Beam Dynamics and EM Fields
D01 Beam Optics - Lattices, Correction Schemes, Transport
Paper Title Page
MOXB02 First Results of the IOTA Ring Research at Fermilab 19
 
  • A. Valishev, D.R. Broemmelsiek, A.V. Burov, K. Carlson, B.L. Cathey, S. Chattopadhyay, N. Eddy, D.R. Edstrom, J.D. Jarvis, V.A. Lebedev, S. Nagaitsev, H. Piekarz, A.L. Romanov, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari
    Fermilab, Batavia, Illinois, USA
  • A. Arodzero, A.Y. Murokh, M. Ruelas
    RadiaBeam, Santa Monica, California, USA
  • D.L. Bruhwiler, J.P. Edelen, C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  • S. Chattopadhyay, S. Szustkowski
    Northern Illinois University, DeKalb, Illinois, USA
  • A. Halavanau, Z. Huang, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • M. Hofer
    TU Vienna, Wien, Austria
  • M. Hofer, R. Tomás García
    CERN, Geneva, Switzerland
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
  • K.-J. Kim
    ANL, Lemont, Illinois, USA
  • K.-J. Kim, Y.K. Kim, N. Kuklev, I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • T.V. Shaftan
    BNL, Upton, New York, USA
  
  Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The IOTA ring at Fermilab is a unique machine exclusively dedicated to accelerator beam physics R&D. The research conducted at IOTA includes topics such as nonlinear integrable optics, suppression of coherent beam instabilities, optical stochastic cooling and quantum science experiments. In this talk we report on the first results of experiments with implementations of nonlinear integrable beam optics. The first of its kind practical realization of a two-dimensional integrable system in a strongly-focusing storage ring was demonstrated allowing among other things for stable beam circulation near or at the integer resonance. Also presented will be the highlights of the world’s first demonstration of optical stochastic beam cooling and other selected results of IOTA’s broad experimental program. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXB02  
About • paper received ※ 20 May 2021       paper accepted ※ 02 July 2021       issue date ※ 23 August 2021  
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MOPAB074 Preliminary Study of Design Method for Hybrid MBA Lattice 297
 
  • J.J. Tan, Z.H. Bai, Z.L. Ren, J.H. Xu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  • Q. Zhang
    INEST, Hefei, People’s Republic of China
  
  Nonlinear optimization of hybrid multi-bend-achromat (HMBA) lattice is a difficult task due to its quite limited variables of multipole magnets. As a result, it is necessary to consider nonlinear potential of the lattice in its linear design. Nonlinear dynamics can be estimated by nonlinear driving terms and detuning terms. In this paper, we propose a design method for HMBA lattice. In this method, objective functions include emittance and two indicators of nonlinear dynamics, which consist of nonlinear driving terms and detuning terms. As an example, an HMBA lattice for a 2.2 GeV storage ring with circumference of 460.8 m was designed to demonstrate the method.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB074  
About • paper received ※ 19 May 2021       paper accepted ※ 21 May 2021       issue date ※ 21 August 2021  
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MOPAB110 An Electron Synchrotron Lattice Based on Theoretic Minimal Emittance Cell 403
 
  • H.C. Chao
    DESY, Hamburg, Germany
  
  A design of an electron synchrotron featuring the theoretic minimal emittance (TME) cells is presented. It has 32 superperiods and the circumference is around 300 m. It offers versatile functions with the equilibrium emittance less than 10 nm-rad at 6 GeV. The beam energy can go up to 7 GeV. Locations with proper phase advances are found to form effective vertical orbit bumps, which can be used for the injections and extraction. A tune scan study shows the sweet spot for the working point. Some discussions of other usages and studies of synchro-betatron coupling effects are also included in this article.  
poster icon Poster MOPAB110 [0.777 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB110  
About • paper received ※ 11 May 2021       paper accepted ※ 28 May 2021       issue date ※ 30 August 2021  
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MOPAB113 A Low-emittance Booster Lattice Design for the SOLEIL Upgrade 410
 
  • M.-A. Tordeux, A. Loulergue, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  • Z.H. Bai, G. Liu, T. Zhang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  The SOLEIL storage ring upgrade will require an injected beam with small transverse and longitudinal sizes. To meet this requirement, the present booster also needs to be upgraded, aiming to reduce the emittance below 10 nm·rad. A multi-bend achromat lattice is designed in this context for the booster upgrade, which consists of two superperiods to respect the present race-track configuration. The lattice is a 16BA HOA (Higher-Order Achromat) type lattice, composed of 14 unit cells, 2 matching cells and a long straight section, and combined-function bending magnets are used in the unit cells to both save space and reduce the emittance. The natural emittance of the designed booster is 5.2 nm·rad at the final energy of 2.75 GeV. This paper presents the general constraints, linear lattice design and nonlinear dynamics optimization for the booster upgrade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB113  
About • paper received ※ 19 May 2021       paper accepted ※ 28 May 2021       issue date ※ 26 August 2021  
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MOPAB139 High Resolution Imaging Design Using Permanent Magnet Quadrupoles at BNL UEM 485
 
  • G. Andonian, T.J. Campese, I.I. Gadjev, M. Ruelas
    RadiaBeam, Marina del Rey, California, USA
  • M.G. Fedurin, K. Kusche, X. Yang, Y. Zhu
    BNL, Upton, New York, USA
  • C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  
  Ultrafast electron microscopy techniques have demonstrated the potential to reach very high combined spatio-temporal resolution. In order to achieve high resolution, strong focusing magnets must be used as the objective and projector lenses. In this paper, we discuss the design and development of a high-resolution objective lens for use in the BNL UEM. The objective lens is a quintuplet array of permanent magnet quadrupoles, which in sum, provide symmetric focusing, high magnification, and control of higher order aberration terms. The application and design for a proof-of-concept experiment using a calibrated slit for imaging are presented. The image resolution is monitored as a function of beam parameters (energy, energy spread, charge, bunch length, spot size), and quintuplet lens parameters (drifts between lenses).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB139  
About • paper received ※ 26 May 2021       paper accepted ※ 28 May 2021       issue date ※ 18 August 2021  
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MOPAB178 Systematic Effects Limiting the Sensitivity of "Magic Energy" Proton EDM Rings 602
 
  • C. Carli, M. Haj Tahar
    CERN, Geneva, Switzerland
  
  Proposals to measure a possible Electric Dipole Moment (EDM) of protons in an electro-static storage ring are studied by a world-wide community. The machine is operated at the so-called "magic energy" to satisfy the "frozen spin" condition such that, without imperfections and with the well known magnetic moment of the particle, the spin is always oriented parallel to the direction of movement. The effect of a finite EDM is a build-up of a vertical spin component. Any effect, other than a finite EDM, leading as well to a build-up of a vertical spin limits the sensitivity of the experiment. Such "systematic effects" are caused by machine imperfections, such as magnetic fields inside the magnetic shield surrounding the ring, and misalignments of electro-static elements or of the RF cavity. Operation of the machine with counter-rotating beams helps mitigating some of the effects. The most dangerous effects are those, which cannot be disentangled from an EDM by combining measurements from both counter-rotating beams, such as an average residual radial magnetic field penetrating the magnetic shield or a combination of magnetic fields and misalignments of electric elements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB178  
About • paper received ※ 18 May 2021       paper accepted ※ 17 June 2021       issue date ※ 20 August 2021  
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MOPAB212 3-D Quantum Lifetime 700
 
  • H. Zhao, M. Blaskiewicz
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The quantum lifetime of electron beam in storage rings is defined by the particle loss that caused by the aperture limitation. Based on the equilibrium beam distribution produced by radiation damping and quantum excitation, the 1-d quantum lifetime has been well studied by A. Piwinski. In this paper, we give the derivation of the 3-d quantum lifetime, which can be applied to the machines with elliptical aperture and momentum acceptance. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB212  
About • paper received ※ 04 June 2021       paper accepted ※ 21 June 2021       issue date ※ 16 August 2021  
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MOPAB213 Characterization of Linear Optics and Beam Parameters for the APS Booster with Turn-by-Turn BPM Data 703
 
  • X. Huang, H. Shang, C. Yao
    ANL, Lemont, Illinois, USA
  
  We take turn-by-turn (TBT) BPM data on the energy ramp of the APS Booster, and analyze the data with the independent component analysis. The extraction kicker was used to excite the betatron motion. The linear optics of the machine is characterized with the TBT BPM data. We also analyze the decoherence pattern of the kicked beam, from which we are able to derive beam distribution parameters, such as the momentum spread.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB213  
About • paper received ※ 13 May 2021       paper accepted ※ 11 June 2021       issue date ※ 19 August 2021  
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MOPAB214 Linear Optics Measurement for the APS Ring with Turn-by-Turn BPM Data 707
 
  • X. Huang, V. Sajaev, Y.P. Sun, A. Xiao
    ANL, Lemont, Illinois, USA
  
  We measure the linear optics of the APS storage ring from turn-by-turn BPM data taken when the beam is excited with an injection kicker. Decoherence due to chromaticity and amplitude-dependent detuning is observed and compared to theoretic predictions. Independent component analysis is used to analyze the data, which separates the betatron normal modes and synchrotron motion, despite contamination of bad BPMs. The beta functions and phase advances are subsequently obtained. The method is used to study the linear optics perturbation of an insertion device.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB214  
About • paper received ※ 12 May 2021       paper accepted ※ 09 June 2021       issue date ※ 01 September 2021  
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MOPAB215 Using ICA for Retrieving Teng Parameters 711
 
  • A. Lauterbach
    IAP, Frankfurt am Main, Germany
  • G. Franchetti
    GSI, Darmstadt, Germany
  
  The blind source separation (BSS) method of Independent Component Analysis (ICA) is explored as a new approach for the reconstruction of the transfer matrix of Linear Coupling Parameterization. ICA is a method to detangle independent signals out of several measurements of their mixtures. In BSS-calculations, it is usually not possible to retrieve the mixing matrix, for the source signals, as well as the matrix, are unknown. Combining the parameterization model of D.A. Edwards and L.C. Teng with the standard ICA approach, it is though possible to retrieve the mixing matrix, as the form of the original uncoupled motion is known. At the same time arises the possibility to recalculate the parameters of Edwards and Teng through a system of equations of the one turn map components. It can be shown as a proof of concept, that the parameters can be reconstructed up to high accuracy for a simulated, non-perturbed signal.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB215  
About • paper received ※ 10 May 2021       paper accepted ※ 31 May 2021       issue date ※ 23 August 2021  
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MOPAB216 20-24 GeV FFA CEBAF Energy Upgrade 715
 
  • S.A. Bogacz, J.F. Benesch, R.M. Bodenstein, B.R. Gamage, G.A. Krafft, V.S. Morozov, Y. Roblin
    JLab, Newport News, Virginia, USA
  • J.S. Berg, S.J. Brooks, D. Trbojevic
    BNL, Upton, New York, USA
  • D. Douglas
    Douglas Consulting, York, Virginia, USA
  • G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177
A proposal was formulated to increase the CEBAF energy from the present 12 GeV to 20-24 GeV by replacing the highest-energy arcs with Fixed Field Alternating Gradient (FFA) arcs. The new pair of arcs would provide six or seven new beam passes, going through this magnet array, allowing the energy to be nearly doubled using the existing CEBAF SRF cavity system. One of the immediate accelerator design tasks is to develop a proof-of-principle FFA arc magnet lattice that would support simultaneous transport of 6-7 passes with energies spanning a factor of two. We also examine the possibility of using combined function magnets to configure a cascade, six-way beam split switchyard. Finally, a novel multi-pass linac optics based on a weakly focusing lattice is being explored. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB216  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 29 August 2021  
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MOPAB217 A Storage Ring for MESA 719
 
  • C.P. Stoll, A. Meseck
    KPH, Mainz, Germany
  • B. Ledroit
    HIM, Mainz, Germany
  
  The Mainz Energy-recovering Superconducting Accelerator (MESA) is an Energy Recovery Linac (ERL) facility under construction at the Johannes Gutenberg-University in Mainz. It provides the opportunity for precision physics experiments with a 1 mA c.w. electron beam in its initial phase. In this phase experiments with unpolarised, high density 1019 atoms cm2 gas jet targets are foreseen at the Mainz Gas Internal Target Experiment (MAGIX). To allow experiments with thin polarised gas targets with sufficiently high interaction rates in a later phase, the beam current has to be increased to up to 100 mA, which would pose significant challenges to the existing ERL machine. Thus, it is proposed here to use MESA in pulsed operation with a repetition rate of several kHz to fill a storage ring, providing a quasi c.w. beam current to a thin gas target. For this purpose, the existing optics need to be extended and adapted, a suitable injection and extraction scheme is necessary and beam target interaction must be investigated. First considerations on these topics are presented here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB217  
About • paper received ※ 18 May 2021       paper accepted ※ 08 June 2021       issue date ※ 21 August 2021  
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MOPAB220 Towards Deterministic Design of MBA-Lattices 722
 
  • B.C. Kuske
    HZB, Berlin, Germany
  
  Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association
Since the pioneering work of MAX IV *, multi-bend achromat (MBA) lattices have become the standard in lattice design for 4th generation lights sources as well as upgrades of 3rd generation storage rings. The distribution of the bending angle to many weak dipoles enables to reach unprecedented low emittance and highest brightness. In their most basic form, MBA-lattices consist of a repetitive unit cell and two identical matching cells on either end of the achromatic arc. The simplicity of both cells allows for a unique determination of the linear lattice parameters in dependence on boundary conditions defined by the design goals. Those might be the emittance, momentum compaction factor, chromaticity, as well as phase advances with respect to achieving higher-order achromatic structures. A scan of optional lattice prototypes is quickly obtained. We demonstrate this concept and apply it in the design of the first candidates for the lattice of BESSY III, a green-field 4th generation storage ring being currently planned at HZB, Berlin, Germany.
* https://www.maxiv.lu.se/accelerators-beamlines/accelerators/accelerator-documentation/max-iv-ddr/ 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB220  
About • paper received ※ 17 May 2021       paper accepted ※ 23 July 2021       issue date ※ 26 August 2021  
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MOPAB221 Developments of a Pulse Kicker System for the Three-Dimensional Spiral Beam Injection of the J-PARC Muon g-2/EDM Experiment 726
 
  • K. Oda, H. Hirayama, H. Iinuma, Y. Sato, M. Sugita
    Ibaraki University, Ibaraki, Japan
  • M. Abe, K. Furukawa, T. Mibe, H. Nakayama, S. Ohsawa, M.A. Rehman, N. Saito, K. Sasaki
    KEK, Ibaraki, Japan
  • R. Matsushita
    The University of Tokyo, Graduate School of Science, Tokyo, Japan
  
  The J-PARC muon g-2/EDM experiment aims to perform ultra-precise measurements of anomalous magnetic moments (g-2) and electric dipole moments (EDM) from the spin precession of muons in a precise magnetic field and to explore new physics beyond the Standard Model. On experimental requirements, the beam must be stored in a compact storage orbit with a diameter of 66 cm, which is about 1/20th smaller than that of the previous experiment. To be realized, we adopt an unprecedented injection technique called the three-dimensional spiral injection scheme. In this scheme, the beam is injected from upward of the solenoidal storage magnet. The vertical beam motion along the solenoid axis is controlled by a few 100 ns pulse kicker. Once the beam is guided into the center fiducial storage volume, the muon beam is stored by the weak focusing magnetic field. Therefore, stable and accurate control of the pulse kicker is one of the major technical challenges to realize the ultra-precise measurement of the muon spin precession. In this presentation, we discuss the performance of the prototype pulse kicker device and future plan for installation of it to our test bench with an electron beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB221  
About • paper received ※ 20 May 2021       paper accepted ※ 31 May 2021       issue date ※ 15 August 2021  
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MOPAB224 Optimization and Error Studies for the USSR HMBA Lattice 730
 
  • L. Hoummi, N. Carmignani, L.R. Carver, S.M. Liuzzo, T.P. Perron, S.M. White
    ESRF, Grenoble, France
  • I.A. Ashanin, S.M. Polozov
    MEPhI, Moscow, Russia
  • T. Kulevoy
    ITEP, Moscow, Russia
  • T. Kulevoy
    NRC, Moscow, Russia
  
  Several new accelerator facilities will be built in Russia in the next few years. One of those facilities is a 6 GeV storage ring (SR) light source, the Ultimate Source of Synchrotron Radiation (USSR) to be built in Protvino, near Moscow. The Cremlin+ project aims to incorporate in this activity the best experience of European Accelerator Laboratories. The optimization of such optics including realistic errors and a commissioning-like sequence of corrections, using Multi-Objective Genetic Algorithms (NSGA-II) is presented. Several corrections schemes are also tested.  
poster icon Poster MOPAB224 [1.164 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB224  
About • paper received ※ 12 May 2021       paper accepted ※ 01 June 2021       issue date ※ 13 August 2021  
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MOPAB225 A HMBA Lattice Design Study for the 4 GeV Light Source 734
 
  • S.W. Jang, E.-S. Kim
    KUS, Sejong, Republic of Korea
  
  The 4th generation storage ring (4GSR) project will start from 2022 in South Korea. We proposed HMBA (Hybrid Multi-Bend Achromatic) lattice for 4GSR with super-bend at the center of the lattice. The 4GSR lattice is designed to combined HMBA lattice with a 4 GeV, 53 pm-rad emittance and 843m. The storage ring including 32 long with 5.65m, 16 short straight with 1.3m sections for IDs and 16 super-bend sections for more different type of beam line experiments. A calculated dynamic aperture is more larger than 15mm in both direction and the beam life time is expected to 4.7 hour. In this paper, we will describe the study results of the HMBA lattice design with a 4GeV light source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB225  
About • paper received ※ 20 May 2021       paper accepted ※ 24 May 2021       issue date ※ 30 August 2021  
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MOPAB226 Analytical Description of the Steerer Parameters in the Bilinear-Exponential Model at DELTA 737
 
  • S. Kötter
    DELTA, Dortmund, Germany
  
  At DELTA, a 1.5 GeV synchrotron radiation source operated by the TU Dortmund University, an analytical description of the steerer parameters in the bilinear-exponential (BE) model has been developed. The BE model describes the coupled orbit response in a storage ring. It is used in the closed-orbit bilinear-exponential analysis (COBEA) algorithm to decompose orbit response matrices into beta function, betatron phase, and a scaled dispersion. After introducing the BE model and the analytical steerer parameters, a simulation-based comparison of the BE model and another coupled orbit response model is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB226  
About • paper received ※ 19 May 2021       paper accepted ※ 08 June 2021       issue date ※ 11 August 2021  
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MOPAB229 Compensations of Third-Order Resonances in J-PARC MR 744
 
  • T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa
    KEK, Tokai, Ibaraki, Japan
  
  The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high-power proton beams for the neutrino and hadron experiments. In the fast extraction (FX) operation, the beams are injected with the energy of 3 GeV and the intensity of 3.3 × 1013 protons per bunch, and accelerated to 30 GeV. Most of the beam losses are observed in the low-energy period, because the space charge tune spread is large, and crosses various kinds of resonances. In this study, the compensations of the third-order resonances are performed. The present operation tune is (νx, νy) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is νx-2νy=-21. It was clearly compensated by optimizing the phase advances in the arc sections. The compensation was confirmed by the aperture survey simulations and demonstrated by the three different experiments. The third-order nonstructure resonances near the operation tune are 3νx=64 and νx+2νy=64. They are simultaneously compensated by introducing four trim coils of the sextupole magnets. The beam loss was successfully reduced by adopting the compensations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229  
About • paper received ※ 20 May 2021       paper accepted ※ 02 June 2021       issue date ※ 29 August 2021  
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MOPAB230 The Optics Design for the Final Focus System of CLIC 380 GeV 748
 
  • A. Pastushenko, R. Tomás García
    CERN, Geneva, Switzerland
  • A. Faus-Golfe
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  
  The first stage of the Compact Linear Collider (CLIC) is planned to be at the center-of-mass energy of 380 GeV. The final focus system (FFS) was re-optimized for this energy and for L* of 6 m (distance between the Interaction Point (IP) and the last quadrupole, QD0). Furthermore, the FFS optics was optimized for the vertical beta-function of 70 microns to approach the Hourglass effect limit. This paper reports the exploration of shortening the Final Doublet (FD) within the FFS to reduce the chromaticity. In addition, an alternative optics design is investigated with a different dispersion profile along the FFS, which outperforms the previous optics with the same β*, increasing luminosity by 5 %.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB230  
About • paper received ※ 19 May 2021       paper accepted ※ 14 June 2021       issue date ※ 11 August 2021  
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MOPAB231 Tunability Study of the Ultra-Low β* Optics at ATF2 with New Octupole Setup and Tuning Knobs 752
 
  • A. Pastushenko, R. Tomás García
    CERN, Geneva, Switzerland
  • A. Faus-Golfe
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • K. Kubo, S. Kuroda, T. Naito, T. Okugi, N. Terunuma, R.J. Yang
    KEK, Ibaraki, Japan
  
  The main goal of the Accelerator Test Facility 2 (ATF2) is to demonstrate the feasibility of future linear colliders’ final focus systems. The Ultra-low β* optics of ATF2 is designed to have the same chromaticity level as CLIC. To ease the tuning procedure, a pair of octupoles was installed in ATF2 in 2017. This paper reports the optimizations performed to the octupoles’ setup for Ultra-low β* optics including the new alignment technique, based on the waist shift and the new tunning knobs constructed for this optics. The full tuning procedure including the static errors is simulated for this setup.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB231  
About • paper received ※ 19 May 2021       paper accepted ※ 28 July 2021       issue date ※ 12 August 2021  
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MOPAB232 Observation of Polarization-Dependent Changes in Higher-Order Mode Responses as a Function of Transverse Beam Position in Tesla-Type Cavities at FAST 756
 
  • R.M. Thurman-Keup, D.R. Edstrom, A.H. Lumpkin, P.S. Prieto, J. Ruan
    Fermilab, Batavia, Illinois, USA
  • J.A. Diaz Cruz
    UNM-ECE, Albuquerque, USA
  • J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora, F. Zhou
    SLAC, Menlo Park, California, USA
  
  Funding: FNAL supported by U.S. Department of Energy, Office of Science, under contract DE-AC02-07CH11359. SLAC supported by U.S. Department of Energy, Office of Science, under contract DE-AC02-76SF00515.
Higher-order modes (HOMs) in superconducting rf cavities present problems for an electron bunch traversing the cavity in the form of long-range wakefields from previous bunches. These may dilute the emittance of the macropulse average, especially with low emittance beams at facilities such as the European X-ray Free-electron Laser (XFEL) and the upgraded Linac Coherent Light Source (LCLS-II). Here we present observations of HOMs driven by the beam at the Fermilab Accelerator Science and Technology (FAST) facility. The FAST facility features two independent TESLA-type cavities (CC1 and CC2) after a photocathode rf gun followed by an 8-cavity cryomodule. The HOM signals were acquired from cavities using bandpass filters of 1.75 ± 0.15 GHz, 2.5 ± 0.2 GHz, and 3.25 ± 0.2 GHz and recorded using an 8-GHz, 20 GSa/s oscilloscope. The frequency resolution obtained is sufficient to separate polarization components of many of the HOMs. These HOM signals were captured from CC1 and cavities 1 and 8 of the cryomodule for various initial trajectories through the cavities, and we observe correlations between trajectory, HOM signals, and which polarization component of a mode is affected. 		 
poster icon Poster MOPAB232 [2.144 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB232  
About • paper received ※ 20 May 2021       paper accepted ※ 25 May 2021       issue date ※ 10 August 2021  
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MOPAB234 Analysis of the Chromatic Vertical Focusing Effect of Dipole Fringe Fields 760
 
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
  
  Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231
There have been questions regarding the impact of the dipole fringe-field models (used by accelerator codes including ELEGANT and MADX) on vertical chromaticity. Here, we analyze the cause of the disagreement among codes and suggest a correction. 		 
poster icon Poster MOPAB234 [0.486 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB234  
About • paper received ※ 20 May 2021       paper accepted ※ 01 June 2021       issue date ※ 23 August 2021  
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MOPAB236 Ion Beam Dynamics in Linac-100 Facility at Jinr 767
 
  • S.M. Polozov, V.S. Dyubkov, Y. Lozeev, T.A. Lozeeva, A.V. Samoshin
    MEPhI, Moscow, Russia
  
  The heavy-ion linac LINAC-100 is a superconducting driver-accelerator proposed as one of the prospective projects at JINR. Its goal is to accelerate primary stable isotope CW high-intensity beams to energies up to 100 MeV/u*. This linac is discussed as the first stage of a new rare isotope facility DERICA (Dubna Electron-Radioactive Ion Collider fAcility), being under development at JINR since 2017**. LINAC-100 is supposed to work with a wide range of beams with A/Z 3.5/7, Uranium U34+ being the heaviest. Its concept has undergone many changes, mostly considering stripping cells to increase accelerator efficiency. During the latest investigations of various stripping cells [***, ****], Uranium beam stripping at the energy 10 MeV/u and utilizing three adjacent charge states 59-61+ resulted in 60% output beam intensity preservation (or 30 pA overall output current). The current layout of the LINAC-100 is the following: one or two (separately for light and heavy ions) normal conducting front-end linacs, gas stripper cell at 10 MeV/u, and the SC section. In this paper three charge state Uranium beam dynamics in the current version of SC LINAC-100 section is presented.
*S Polozov 2020 PhysScr 95 084006
**A S Fomichev Phys Usp 62(7) 675-690 2019
***Tolstikhina I 2018 Basic At Int of Acc H Ions in Matter 98 1
**** W Barth J Phys Conf Ser 1350:012096 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB236  
About • paper received ※ 20 May 2021       paper accepted ※ 17 August 2021       issue date ※ 26 August 2021  
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MOPAB239 Simulation and Optimization of the Spin Coherence Time of Protons in a Prototype EDM Ring 771
 
  • M. Vitz, A. Lehrach
    FZJ, Jülich, Germany
  • R. Shankar
    INFN-Ferrara, Ferrara, Italy
  
  The matter-antimatter asymmetry might be understood by investigating the EDM (Electric Dipole Moment) of elementary charged particles. A permanent EDM of a subatomic particle violates time-reversal and parity symmetry at the same time and would be, with the currently achievable experimental accuracy, a strong indication for physics beyond the Standard Model. The JEDI-Collaboration (Jülich Electric Dipole moment Investigations) in Jülich is preparing a direct EDM measurement for protons and deuterons: first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. A prototype EDM ring is an intermediate step before building the final storage ring to demonstrate sufficient beam lifetime and SCT (Spin Coherence Time) in a pure electrostatic ring as well as in a storage ring with combined electric and magnetic bending elements. In order to study the effect of E-B-deflectors on the orbit and the spin motion, the software library Bmad is used. The first results of the optics and spin simulations, with a focus on the optimization of the SCT, towards the prototype EDM ring will be discussed.  
poster icon Poster MOPAB239 [0.560 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB239  
About • paper received ※ 17 May 2021       paper accepted ※ 09 June 2021       issue date ※ 23 August 2021  
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MOPAB240 Estimates of Damped Equilibrium Energy Spread and Emittance in a Dual Energy Storage Ring 774
 
  • B. Dhital, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, and Office of Nuclear Physics under Contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. / Jefferson Lab EIC Fellowship2020.
A dual energy storage ring design consists of two loops at markedly different energies. As in a single-energy storage ring, the linear optics in the ring design may be used to determine the damped equilibrium emittance and energy spread. Because the individual radiation events in the two rings are different and independent, we can provide analytical estimates of the damping times in a dual energy storage ring. Using the damping times, the values of damped energy spread, and emittance can be determined for a range of parameters related to lattice design and rings energies. We present analytical calculations along with simulation results to estimate the values of damped energy spread and emittance in a dual energy storage ring. We note that the damping time tends to be dominated by the damping time of the high energy ring in cases where the energy of the high energy rings is significantly greater than that of the low energy ring. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB240  
About • paper received ※ 17 May 2021       paper accepted ※ 27 May 2021       issue date ※ 13 August 2021  
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MOPAB241 Design of the Proton and Electron Transfer Lines for AWAKE Run 2c 778
 
  • R.L. Ramjiawan
    JAI, Oxford, United Kingdom
  • S. Döbert, E. Gschwendtner, P. Muggli, F.M. Velotti, L. Verra
    CERN, Meyrin, Switzerland
  • J.P. Farmer
    MPI-P, München, Germany
  • P. Muggli
    MPI, Muenchen, Germany
  
  The AWAKE Run 1 experiment achieved electron acceleration to 2 GeV using plasma wakefield acceleration driven by 400 GeV, self-modulated proton bunches from the CERN SPS. The Run 2c phase of the experiment aims to build on these results by demonstrating acceleration to ~10 GeV while preserving the quality of the accelerated electron beam. To realize this, there will be an additional plasma cell, to separate the proton bunch self-modulation and the electron acceleration. A new 150 MeV beamline is required to transport and focus the witness electron beam to a beam size of several microns at the injection point. This specification is designed to preserve the beam emittance during acceleration, also requiring micron-level stability between the driver and witness beams. To facilitate these changes, the Run 1 proton transfer line will be reconfigured to shift the first plasma cell 40 m downstream. The Run 1 electron beamline will be adapted and used to inject electron bunches into the first plasma cell to seed the proton bunch self-modulation. Proposed adjustments to the proton transfer line and studies for the designs of the two electron transfer lines are detailed in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB241  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 17 August 2021  
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MOPAB242 A Six-Bend-Achromat Lattice for a 2.5 GeV Diffraction-Limited Storage Ring 782
 
  • J. Li, M. Abo-Bakr, P. Goslawski
    HZB, Berlin, Germany
  • Z.H. Bai
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  HZB has proposed a 2.5 GeV diffraction-limited storage ring as the upgrade of BESSY II. A Six-Bend-Achromat lattice based on Higher-Order Achromat, as one of the possible solutions, has been designed to meet the requirements of low emittance, compact layout, large dynamic aperture and large momentum acceptance. The linear lattice design and the nonlinear performance are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB242  
About • paper received ※ 18 May 2021       paper accepted ※ 09 June 2021       issue date ※ 17 August 2021  
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MOPAB245 Theoretical Analysis of the Conditions for an Isochronous and CSR-Immune Triple-Bend Achromat with Stable Optics 786
 
  • C. Zhang, Y. Jiao
    IHEP, Beijing, People’s Republic of China
  • C.-Y. Tsai
    HUST, Wuhan, People’s Republic of China
  
  Funding: National Natural Science Foundation of China (No. 11922512), Youth Innovation Promotion Association of Chinese Academy of Sciences (No. Y201904), National Key R&D Program of China (No. 2016YFA0401900)
Transport of high-brightness beams with minimum degradation of the phase space quality is pursued in modern accelerators. For the beam transfer line which commonly consists of bending magnets, it would be desirable if the transfer line can be isochronous and coherent synchrotron radiation (CSR)-immune. For multi-pass transfer line, the achromatic cell designs with stable optics would bring great convenience. In this paper, based on the transfer matrix formalism and the CSR point-kick model, we report the detailed theoretical analysis and derive the condition for a triple-bend achromat with stable optics in which the first-order longitudinal dispersion (i.e., R56) and the CSR-induced emittance growth can be eliminated. The derived condition suggests a new way of designing the bending magnet beamline that can be applied to the free-electron laser (FEL) spreader and energy recovery linac (ERL) recirculation loop. 		 
poster icon Poster MOPAB245 [0.530 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB245  
About • paper received ※ 12 May 2021       paper accepted ※ 08 June 2021       issue date ※ 27 August 2021  
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MOPAB246 Design of the MEBT for the JAEA-ADS Project 790
 
  • B. Yee-Rendón, Y. Kondo, F.M. Maekawa, S.I. Meigo, J. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
  
  The Medium Energy Beam Transport (MEBT) will transport a CW proton beam with a current of 20 mA and energy of 2.5 MeV from the exit of the normal conducting Radiofrequency Quadrupole (RFQ) to the superconducting Half-Wave resonator (HWR) section. The MEBT must provide a good matching between the RFQ and HWR, effective control of the emittance growth and the halo formation, enough space for all the beam diagnostics devices, among others. This work reports the first lattice design and the beam dynamics studies for the MEBT of the JAEA-ADS.  
poster icon Poster MOPAB246 [0.827 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB246  
About • paper received ※ 10 May 2021       paper accepted ※ 02 June 2021       issue date ※ 19 August 2021  
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MOPAB248 Injection Schemes for the SOLEIL Upgrade 796
 
  • M.-A. Tordeux, P. Alexandre, R. Ben El Fekih, P. Brunelle, L. Hoummi, A. Loulergue, L.S. Nadolski, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  
  Injection into the SOLEIL upgrade storage ring is much more challenging compared to the case of the current ring. Thanks to the experience gained in the development, manufacture and commissioning of a Multipole Injection Kicker (MIK) on the MAX IV 3 GeV storage ring, the SOLEIL pulsed magnet team is currently developing new MIK magnets that will serve as the basis for the injection schemes in the upgrade storage ring. We then propose two kinds of injections: firstly, a betatron off-axis injection that should be compatible with the full-coupling storage ring tuning, and secondly, a synchrotron on-axis injection by creating a large horizontal dispersion bump at the injection point.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB248  
About • paper received ※ 19 May 2021       paper accepted ※ 21 May 2021       issue date ※ 26 August 2021  
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MOPAB253 Comparison of Transfer Map Derivation Methods for Static Magnetic Fields 799
 
  • J.A. Crittenden, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This work is supported by National Science Foundation award numbers DMR-1829070 and PHY-1757811.
We compare methods for deriving transfer maps for static magnetic fields, including field-map tracking and tracking elements defined by multipole content. Building on prior work on quantitative evaluation of the accuracy of finite-element models used to produce field maps, we assess the tradeoffs between computing time and fidelity to the underlying magnetic field, including fringe fields, of the various approximate methods. We illustrate our approach using the example of electromagnets in the south arc of the 6-GeV Cornell High Energy Synchrotron Source, which have been operating since 2019. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB253  
About • paper received ※ 19 May 2021       paper accepted ※ 18 June 2021       issue date ※ 13 August 2021  
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MOPAB254 Measurement of Horizontal Beam Size Using Sextupole Magnets 802
 
  • J.A. Crittenden, K.E. Deitrick, H.X. Duan, G.H. Hoffstaetter, V. Khachatryan, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This work is supported by National Science Foundation award number DMR-1829070.
The quadratic dependence of sextupole fields on position results in a beam-size-dependent kick on a beam traversing a sextupole magnet. A change in sextupole strength changes the closed orbit and the tune of the beam in a storage ring. Measuring both therefore allows conclusions about the beam size in the sextupole. Here we derive the pertinent formula and discuss the applicability to storage rings. In particular we investigate the measurement accuracy that can be achieved at the Cornell High Energy Synchrotron Source. The Cornell Electron-positron Storage Ring underwent a major upgrade in 2018 with the goal of reducing the emittance by a factor of four. A variety of beam size measurement methods have been developed to monitor the positron beam size, including visible synchrotron light and interferometry. We investigate the sensitivity of the sextupole method and compare to other measurement techniques. The design horizontal emittance of the 6-GeV positron beam is about 30 nm-rad with typical beam sizes of about 1 mm, setting the scale for the required accuracy in the beam-size measurement. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB254  
About • paper received ※ 19 May 2021       paper accepted ※ 22 June 2021       issue date ※ 01 September 2021  
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MOPAB255 Demonstration of a Novel Longitudinal Phase Space Linearization Method without Higher Harmonics 805
 
  • R. Stark
    University of Hamburg, Hamburg, Germany
  • K. Flöttmann, M. Hachmann
    DESY, Hamburg, Germany
  • F.J. Grüner
    Center for Free-Electron Laser Science, Universität Hamburg, Hamburg, Germany
  • B. Zeitler
    CFEL, Hamburg, Germany
  
  Nonlinear correlations in the longitudinal phase space of electron bunches can be a decisive limitation to the achievable bunch length compression and attainability of small energy spreads. To overcome the restrictions imposed by nonlinear distortions, the longitudinal phase space distribution must be linearized. Previously, a novel linearization procedure based on the controlled expansion of the bunch between two radio frequency cavities operated at the same fundamental frequency has been presented in *. A demonstration of this linearization method is presented in this work.
*B. Zeitler, K. Floettmann, and F. Grüner, "Linearization of the longitudinal phase space without higher harmonic field," Phys. Rev. ST Accel. Beams, vol. 18, p. 120102, 2015. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB255  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 16 August 2021  
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MOPAB256 Development of Pulsed Beam System for the Three Dimensional Spiral Injection Scheme in the J-PARC muon g-2/EDM Experiment 809
 
  • R. Matsushita
    The University of Tokyo, Graduate School of Science, Tokyo, Japan
  • M. Abe, K. Hurukawa, T. Mibe, H. Nakayama, S. Ohsawa, M.A. Rehman, N. Saito, K. Sasaki
    KEK, Ibaraki, Japan
  • H. Hirayama, H. Iinuma, K. Oda, Y. Sato, M. Sugita
    Ibaraki University, Ibaraki, Japan
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • T. Takayanagi
    JAEA/J-PARC, Tokai-mura, Japan
  
  The J-PARC muon g-2/EDM experiment aims to measure the anomalous magnetic moment(g-2) and electric dipole moment(EDM) of the muon with higher precision than the previous BNL E821 experiment. A brand-new three-dimensional spiral injection scheme is employed to inject and store muon beam into a 66 cm diameter of storage magnet. Feasibility studies are ongoing by use of 80 keV electron beam at KEK test bench, to develop skills on control transverse beam motion; so-called X-Y coupling, with DC beam. As a next step, towards store the beam by use of a kicker system, a pulsed beam should be generated from the DC beam with an intended time structure to meet a pulse kicker’s duration time, without changing transverse phase space characteristics. In this presentation, the development of a beam chopper device and the evaluation of pulse beam profile are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB256  
About • paper received ※ 20 May 2021       paper accepted ※ 15 June 2021       issue date ※ 16 August 2021  
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MOPAB257 Effects of Mode Launcher on Beam Dynamics in Next Generation High Brightness C-Band Guns 813
 
  • A. Giribono, D. Alesini, F. Cardelli, G. Di Raddo, M. Ferrario, A. Gallo, J. Scifo, C. Vaccarezza, A. Vannozzi
    INFN/LNF, Frascati (Roma), Italy
  • G. Castorina
    AVO-ADAM, Meyrin, Switzerland
  • L. Ficcadenti
    INFN-Roma, Roma, Italy
  • G. Muti
    Sapienza University of Rome, Rome, Italy
  • G. Pedrocchi
    SBAI, Roma, Italy
  
  High-brightness RF photo-injectors plays nowadays a crucial role in the fields of radiation generation and advanced acceleration schemes. A high gradient C-band photoinjector consisting of a 2.5 cell gun followed by TW sections is here proposed as an electron source for radiation user facilities. The paper reports on beam dynamics studies in the RF injector and illustrates the effects on the beam quality of the mode launcher with a focus on the compensation of the quadrupole RF components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB257  
About • paper received ※ 19 May 2021       paper accepted ※ 08 June 2021       issue date ※ 16 August 2021  
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MOPAB258 Corrections of Non-Linear Field Errors with Asymmetric Optics in LHC and HL-LHC Insertion Regions 817
 
  • J. Dilly, E.H. Maclean, R. Tomás García
    CERN, Geneva, Switzerland
  
  Funding: Research supported by the HL-LHC project, CERN and the german Federal Ministry of Education and Research.
Existing correction schemes to locally suppress resonance driving terms in the error-sensitive high-beta regions of the LHC and HL-LHC have operated on the assumption of symmetric beta-functions of the optics in the two rings. As this assumption can fail for a multitude of reasons, such as inherently asymmetric optics and unevenly distributed errors, an extension of this correction scheme has been developed removing the need for symmetry by operating on the two separate optics of the beams at the same time. Presented here is the impact of this novel approach on dynamic aperture as an important measure of particle stability. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB258  
About • paper received ※ 10 May 2021       paper accepted ※ 23 July 2021       issue date ※ 16 August 2021  
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MOPAB259 Corrections of Feed-Down of Non-Linear Field Errors in LHC and HL-LHC Insertion Regions 821
 
  • J. Dilly, E.H. Maclean, R. Tomás García
    CERN, Geneva, Switzerland
  
  Funding: Research supported by the HL-LHC project, CERN and the german Federal Ministry of Education and Research.
The optics in the insertion regions of the LHC and its upgrade project the High Luminosity LHC (HL-LHC) are very sensitive to local magnetic errors, due to the extremely high beta-functions present. In collision optics, the non-zero closed orbit in the same region leads to a "feed-down" of high-order errors to lower orders, causing additional effects detrimental to beam lifetime. An extension to the proven method for correcting these errors by locally suppressing resonance driving terms has been undertaken, not only taking this feed-down into account, but also adding the possibility of utilizing it such that the powering of higher-order correctors will compensate for lower order errors. The impact of these corrections on measures of particle stability, namely dynamic aperture and amplitude detuning are presented in this contribution. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB259  
About • paper received ※ 10 May 2021       paper accepted ※ 23 July 2021       issue date ※ 15 August 2021  
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MOPAB260 Optics Corrections with LOCO on Sirius Storage Ring 825
 
  • M.B. Alves
    LNLS, Campinas, Brazil
  
  Sirius is a 4th generation 3GeV synchrotron light source at the Brazilian Center for Research in Energy and Materials (CNPEM). In this work, we report the results of linear optics and coupling corrections during the commissioning of Sirius storage ring, using the Linear Optics from Closed Orbits (LOCO) algorithm. Beam-based measurements were performed to verify independently the impact of corrections on storage ring parameters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB260  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 30 August 2021  
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MOPAB261 NSLS-II Storage Ring Lattice Analysis using Response Matrices 829
 
  • J. Choi
    BNL, Upton, New York, USA
  
  Funding: Work supported by the U.S. Department of Energy (DOE) under contract No. DE-SC0012704.
Affected from various sources, the NSLS-II storage ring lattice is slightly changing operation to operation and, for the operational performance, we are continually optimizing the lattice and maintaining the response matrices for the feedback and lattice analysis. Because not all sources are identified, we are investing efforts to identify as many as possible. As one of such efforts, we also study the measured response matrices. In this paper, we present the results of lattice studies using a pair of recently measured response matrices. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB261  
About • paper received ※ 20 May 2021       paper accepted ※ 02 June 2021       issue date ※ 19 August 2021  
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MOPAB263 Preliminary Beam Dynamics Studies for 200 MeV Superconducting Linac Planned at KOMAC 837
 
  • S. Lee, J.J. Dang, H.S. Kim, H.-J. Kwon
    Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
  • Y.-S. Cho
    KAERI, Daejon, Republic of Korea
  
  Funding: This work has been supported through KOMAC operation fund of KAERI by the Korea government (MSIT).
Korea Multi-purpose Accelerator Complex (KOMAC) is planning an energy upgrade of the existing 100 MeV proton linac to 200 MeV using a superconducting Half Wave Resonator (HWR) operating at 350 MHz. A cryomodule is planned to house four HWR cavities with a warm doublet focusing lattice structure. Matching between the already existing DTL section and HWR section is designed and studied. We report the preliminary study of the beam dynamics of the 200 MeV superconducting linac carried out at KOMAC. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB263  
About • paper received ※ 20 May 2021       paper accepted ※ 01 July 2021       issue date ※ 24 August 2021  
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MOPAB264 Commissioning of the DESIR High-Resolution Separator at CENBG 841
 
  • J. Michaud, P. Alfaurt, A. Balana, B. Blank, L. Daudin, T. Kurtukian-Nieto, S. Leblanc, L.S. Serani
    CENBG, Gradignan, France
  • F. Méot
    BNL, Upton, New York, USA
  • F. Varenne
    GANIL, Caen, France
  
  DESIR is the low-energy part of the SPIRAL2 ISOL facility under construction at GANIL. The high-resolution mass separator (HRS) included in DESIR is a 180 degree symmetric online separator with two 90 degree magnetic dipole sections arranged with electrostatic quadrupoles, sextupoles and a multipole on the mid plane. The HRS is now completely mounted at CENBG and under commissioning for the next 2 to 3 years before its transfer at the entrance of the DESIR facility. The objective is to test, characterise and correct all HRS elements contributing to the higher order aberration by performing experimental measurements and comparing them with the results from different simulation tools. The recently mounted pepperpot-type emittance-meter will allow us to observe the emittance figures and dynamically tune the multipole to improve the optical parameters of the HRS. We will present the first results concerning the hexapolar correction with the multipole, the associated emittance measurements and the resolution currently achieved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB264  
About • paper received ※ 19 May 2021       paper accepted ※ 08 June 2021       issue date ※ 10 August 2021  
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MOPAB267 End to End Simulations of Antiproton Transport and Degradation 847
 
  • S. Padden, E. Kukstas, P. Pusa, V. Rodin, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • K. Nordlund
    HIP, University of Helsinki, Finland
  • V. Rodin, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  The ELENA ring decelerates anti-protons to 100 keV down from 5.3 MeV with transport to experiments handled by electrostatic transfer lines. Even at 100 keV antiprotons are still too high in energy for direct injection into an ion trap, and this is why degrader foils are used to further lower the energy. This contribution presents full end-to-end simulations from the point of extraction until passing through the foil using realistic beam transport simulations coupled with accurate simulations of degrader foils via the use of density functional theory and molecular dynamics. Particles are tracked from the point of extraction until their injection into the trap with full physical modeling at all time steps. The results of this study provide a versatile platform for the optimization of low energy ion experiments towards specific targets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB267  
About • paper received ※ 19 May 2021       paper accepted ※ 09 June 2021       issue date ※ 24 August 2021  
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MOPAB268 Design of a Continuous Wave Heavy Ion RFQ for BISOL 851
 
  • S. Liu, M.Y. Han, Y.R. Lu, Q.Y. Tan, Z. Wang
    PKU, Beijing, People’s Republic of China
  
  The Beijing isotope separation online (BISOL) facility will be used to study the new physics and technologies at the limit of the nuclear stability. The post accelerator for BISOL facility aims to accelerate radioactive beams to 150MeV/u. As an injector for the downstream superconducting linac, a 4-vane RFQ operating at 81.25MHz is needed to accelerate high-charge-state ions such as 132Sn22+ from 3keV/u to 500keV/u in CW mode. We have compared two kinds of beam dynamics of BISOL RFQ with and without a Multi-Harmonic Buncher (MHB) bunching the continuous wave beam up-stream of the RFQ. The results indicate that it is possible to keep transverse emittance growth within tolerable limits while the longitudinal emittance is much smaller than the design without an external buncher. The acceleration of multi-charge beams simultaneously in the RFQ is also discussed in this paper.  
poster icon Poster MOPAB268 [1.829 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB268  
About • paper received ※ 19 May 2021       paper accepted ※ 25 May 2021       issue date ※ 16 August 2021  
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MOPAB269 Three Approaches for Complete Measurement of the Transverse Beam Optics Along the Fermilab Muon Campus Extraction Line 854
 
  • B.D. Simons, M.J. Syphers
    Northern Illinois University, DeKalb, Illinois, USA
  • D. Stratakis, M.J. Syphers
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work was supported through grant DE-SC0020379 with the United States Department of Energy.
Traditionally, the process of measuring the optical parameters of a beamline has employed the use of one of two standard methods, namely the three-screen method or a quadrupole magnet scan. Both require either an area of zero dispersion to perform the measurements or knowledge of the dispersion function and momentum spread beforehand in order to provide accurate results. There is however a third method that can be used to measure the standard optical parameters, the beam parameters, the dispersion function, and the momentum spread simultaneously. This method, aptly named the six-screen method, is an extension of the more standard three-screen method. Utilizing the simulation environment of G4beamline, we simulated the 8 GeV proton beam in the M4 beamline and measured the optical and beam parameters using the two standard approaches. Those results were then used as a reference to check the viability of employing the less standard six-screen method in the M4 line. If shown to be a viable option, the six-screen method could be used to retrieve the dispersion function and momentum spread of the beam without needing to change the energy of the beam. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB269  
About • paper received ※ 20 May 2021       paper accepted ※ 07 June 2021       issue date ※ 12 August 2021  
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MOPAB270 Beam Dynamics Studies in a Standing Wave Ka-band Linearizer 857
 
  • J. Scifo, M. Behtouei, L. Faillace, M. Ferrario, A. Giribono, B. Spataro, C. Vaccarezza
    INFN/LNF, Frascati, Italy
  • M. Migliorati
    INFN-Roma1, Rome, Italy
  • M. Migliorati
    Sapienza University of Rome, Rome, Italy
  • G. Torrisi
    INFN/LNS, Catania, Italy
  
  Next-generation FEL user facilities require high-quality electron beams with kA peak current. The combination of a high brightness RF injector and a magnetic compression stage represents a very performant solution in terms of electron beam emittance and peak current. One of the important issues is the design of a proper device that acts as a linearizer for the beam longitudinal phase space. Recently, the design of a SW Ka band RF accelerating structure has been proposed with promising results. The paper reports on electron beam dynamics studies in the described RF structure.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB270  
About • paper received ※ 19 May 2021       paper accepted ※ 29 August 2021       issue date ※ 26 August 2021  
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MOPAB272 Consideration the Prospects of Beam Diagnostic System Upgrade in the Transport Channels of Injection Complex VEPP-5 860
 
  • K.V. Astrelina, F.A. Emanov
    BINP SB RAS, Novosibirsk, Russia
  • F.A. Emanov
    NSU, Novosibirsk, Russia
  
  Transport electron and positron channels from linear accelerator to storage ring of Injection Complex VEPP-5 (BINP, Novosibirsk) have complicated 3D configuration and equipped only with luminophore screens as a beam test. For the regular machine operations the non-destructive beam diagnostic system is required to adjust the electron and positron beam trajectories and minimize the beam losses. The proposal of new beam position monitors (BPM) assembling is considered. Newly added BPMs allow one to control the beam trajectory during operations. Collecting beam position data in several points makes it possible to calculate and correct the beamline parameters: Twiss parameters, dispersion, beam energy variations. The possible configuration of the new BPMs placing is suggested and the rate of beam loss reducing due the additional diagnostics is estimated.  
poster icon Poster MOPAB272 [1.164 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB272  
About • paper received ※ 20 May 2021       paper accepted ※ 02 June 2021       issue date ※ 02 September 2021  
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TUXA02
 Beam Dynamics Optimization in High-Brightness Electron Injectors  
 
  • C.E. Mitchell
    LBNL, Berkeley, California, USA
  
  Funding: The work was supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-05CH11231.
The next generation of X-ray free electron lasers requires beams with increasingly high peak current and low emittances at ~MHz repetition rates, placing increased demands on the performance of high-brightness electron photoinjector sources. To explore the high- dimensional parameter space associated with photoinjector design, global multiobjective optimization methods based on genetic algorithms or similar tools play a critical role. We review our experience applying these tools both to understand and to optimize simulated injector beam performance for projects such as LCLS-II (at SLAC), the Advanced Photoinjector EXperiment (at LBNL), APEX2, and potential future high-brightness FEL electron sources. 		 
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TUXA07 Beam Dynamics Study in a Dual Energy Storage Ring for Ion Beam Cooling* 1290
 
  • B. Dhital, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: * Work supported by the U.S. Department of Energy, Office of Science, and Office of Nuclear Physics under Contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. / Jefferson Lab EIC Fellowship2020.
A dual energy storage ring designed for beam cooling consists of two closed rings with significantly different energies: the cooling and damping rings. These two rings are connected by an energy recovering superconducting RF structure that provides the necessary energy difference. In our design, the RF acceleration has a main linac and harmonic cavities both running at crest that at first accelerates the beam from low energy EL to high energy EH and then decelerates the beam from EH to EL in the next pass. The purpose of the harmonic cavities is to extend the bunch length in a dual energy storage ring as such a longer bunch length may be very useful in a cooling application. Besides these cavities, a bunching cavity running on zero-crossing phase is used outside of the common beamline to provide the necessary longitudinal focusing for the system. In this paper, we present a preliminary lattice design along with the fundamental beam dynamics study in such a dual energy storage ring. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA07  
About • paper received ※ 19 May 2021       paper accepted ※ 07 June 2021       issue date ※ 28 August 2021  
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TUPAB003 Final Focus Solenoids Beam-Based Positioning Tests 1330
 
  • D.B. Shwartz
    BINP SB RAS, Novosibirsk, Russia
  • D.B. Shwartz
    NSU, Novosibirsk, Russia
  
  The final focusing at the VEPP-2000 electron-positron collider is done by 13 T superconducting solenoids. The misalignment of solenoids not only provides closed orbit distortions but also harmful for dynamic aperture reduction due to strong nonlinear fringe fields. The final beam-based alignment of solenoids was foreseen but turned out to be not a trivial procedure. Here we present the test study of solenoids positioning reconstruction procedure based on circulating beam orbit responses.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB003  
About • paper received ※ 22 May 2021       paper accepted ※ 02 June 2021       issue date ※ 28 August 2021  
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TUPAB170 Decouple Transverse Coupled Beam in the DTL with Tilted PMQs 1785
 
  • P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • Y.H. Pu, J. Qiao, C.P. Wang, X.C. Xie, F. Yang
    Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People’s Republic of China
  
  The coupling of the beam is widely studied in the accelerator physics field. Projected transverse emittances easily grow up if the beam is transversely-coupled. If we decouple the transverse coupled beam, the transverse emittance can be small. The matrix approach based on the symplectic transformation theory for decoupling the coupled beam is summarized. For a proton accelerator, the transverse coupled beam is introduced by an RFQ tilted by 45°. The beam is decoupled with the first five tilted quadrupoles mounted in the DTL section. A study on the gradient choice of the quadrupoles and the space charge effect is given in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB170  
About • paper received ※ 08 May 2021       paper accepted ※ 21 June 2021       issue date ※ 28 August 2021  
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TUPAB171 Linear Transfer Matrix of a Half Solenoid 1789
 
  • P.F. Ma, X. Guan, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  
  Solenoid magnets can provide strong transverse focusing to electrons and ions with relatively small energies. For the ECR heavy-ion source, the ions are extracted at the central area of the solenoid, the beam is coupled at the exit of the source. The coupling caused by the solenoids can lead to the growth of projected transverse emittance, which has been widely studied with great interest. It is important to study the transfer matrix of a half solenoid to study the beam optics in an ECR souce, thus the property of the beam can be given. Based on the transfer matrix calculation, the summary of the linear transfer matrix of a half solenoid can be given. The beam optics in a half solenoid is studied.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB171  
About • paper received ※ 18 May 2021       paper accepted ※ 28 June 2021       issue date ※ 29 August 2021  
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WEPAB257 Matching of a Space-Charge Dominated Beam into the Undulator of the THz SASE FEL at PITZ 3244
 
  • X. Li, Z. Aboulbanine, G.D. Adhikari, N. Aftab, Z.G. Amirkhanyan, P. Boonpornprasert, M.E. Castro Carballo, N. Chaisueb, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, O. Lishilin, A. Lueangaramwong, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, G. Shu, F. Stephan, G. Vashchenko, T. Weilbach
    DESY Zeuthen, Zeuthen, Germany
  
  The Photo Injector Test facility at DESY in Zeuthen (PITZ) is developing a THz SASE FEL as a prototype high repetition rate accelerator-based source for the THz-pumped, X-ray-probed experiments at the European XFEL. For the generation of THz pulses of mJ-level energy from SASE, an electron beam with a high charge (up to 4 nC) and high peak current (~200 A) will be injected into an LCLS-I undulator, which is currently being installed at the end of the photo-injector. The narrow vacuum chamber (11x5 mm) between the magnetic poles and the strong vertical focusing from the undulator, as well as the lack of beam diagnostics, have made it a challenge to match the space-charge dominated beam into the undulator without beam loss during the following transport. In this paper, boundary conditions of a matched electron beam will be discussed and the simulation and experimental study on our matching strategy will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB257  
About • paper received ※ 08 May 2021       paper accepted ※ 02 July 2021       issue date ※ 13 August 2021  
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WEPAB263 Complex Unit Lattice Cell for Low-Emittance Synchrotrons 3254
 
  • Z.L. Ren, Z.H. Bai, J.J. Tan, L. Wang, H. Xu, P.H. Yang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  To reach the real diffraction-limited emittance, it is generally required to increase the number of bends in multi-bend achromat (MBA) lattices that are used in the designs of fourth-generation synchrotron light sources. For an MBA lattice with distributed chromatic correction, more bends mean much tighter space and much stronger magnets. Inspired by the hybrid MBA lattice concept, in this paper we propose a new lattice concept called complex unit lattice cell, which can save space and reduce magnet strengths. A 17BA lattice based on the complex unit cell concept is designed for a 3 GeV synchrotron light source with a circumference of 537.6 m, which reaches a natural emittance of about 21 pm·rad. Comparison is also made between this 17BA lattice and the 17BA lattice with distributed chromatic correction to demonstrate the merit of the complex unit cell concept.  
poster icon Poster WEPAB263 [1.279 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB263  
About • paper received ※ 16 May 2021       paper accepted ※ 02 July 2021       issue date ※ 12 August 2021  
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WEPAB400 Forced Coupling Resonance Driving Terms 3646
 
  • A. Wegscheider, R. Tomás García
    CERN, Meyrin, Switzerland
  
  At the LHC, coupling is routinely measured using forced oscillations of the beam through excitation with an AC-dipole. The driving of the particle motion has an impact on the measurement of resonance driving terms. Recent findings suggest that the current models describing the forced motion are neglecting a local effect of the AC-dipole, creating a jump of the amplitude of the resonance driving terms. This work presents a study of the improvement of coupling measurements for typical LHC optics as well as its upgrade project HL-LHC, by using the new model.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB400  
About • paper received ※ 19 May 2021       paper accepted ※ 02 August 2021       issue date ※ 20 August 2021  
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THXA03
 Simultaneous Top-Up Injection Into Four Storage Rings at SuperKEKB  
 
  • M. Satoh
    KEK, Ibaraki, Japan
  
  The injector linac at KEK is being upgraded for SuperKEKB, where ten-times smaller emittance and five-times larger current in injection beam are required as compared to KEKB. An RF gun and damping ring were built to generate low emittance beams for the SuperKEKB electron (HER) and positron (LER) beams, respectively. A pulse-to-pulse beam modulation scheme for delivery of beam to the 7 GeV HER and 4 GeV LER, as well as to the 2.5 GeV Photon Factory (PF) ring and the and 6.5 GeV PF-AR ring, has been successfully developed, and simultaneous top-up injections are carried out during SuperKEKB Phase III commissioning. The linac upgrades needed for these simultaneous top-up injections are reported here.  
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THXA07 Driven 3D Beam Oscillations for Optics Measurements in Synchrotrons 3704
 
  • L. Malina, J.M. Coello de Portugal, H. Timko, R. Tomás García
    CERN, Geneva, Switzerland
  
  Optics measurements in storage rings employ turn-by-turn data of transversely excited beams. Traditionally, to measure chromatic properties, the relative momentum is changed step-wise, which is time-consuming and almost impractical during the energy ramp. We present an optics measurement method based on adiabatic simultaneous 3-dimensional beam excitation, which is more time-efficient and well fitted for the energy ramp. This method was successfully demonstrated in the LHC utilising AC-dipoles in combination either with a slow RF-frequency modulation or a driven RF-phase modulation close to the synchrotron frequency. Faster longitudinal oscillations improve the accuracy of optics parameters inferred from the synchro-betatron sidebands. This paper reports on the experimental demonstration of optics measurements based on 3D driven beam excitations and the plans for LHC Run 3.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA07  
About • paper received ※ 19 May 2021       paper accepted ※ 02 August 2021       issue date ※ 11 August 2021  
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THPAB055 Reconstruction of Linear Optics Observables Using Supervised Learning 3875
 
  • E. Fol, H. Garcia, R. Tomás García
    CERN, Meyrin, Switzerland
  
  In the LHC, most of the optical functions can be obtained from turn-by-turn beam centroid data. However, the measurement of such observables as β* and the dispersion function require special dedicated techniques and additional operational time. In this work, we propose an alternative approach to estimate these observables using supervised machine learning, in case the dedicated measurements are not available but turn-by-turn data are. The performance of developed estimators is demonstrated on LHC simulations. Comparison to traditional techniques for the computation of beta-function will be also provided.  
poster icon Poster THPAB055 [0.713 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB055  
About • paper received ※ 19 May 2021       paper accepted ※ 19 July 2021       issue date ※ 15 August 2021  
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THPAB224 The Correction of Time-Dependent Tune Shift by Harmonic Injection 4234
 
  • X.H. Lu
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • J. Chen, S. Wang, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
  
  In the Rapid Cycling Synchrotron(RCS) of China Spallation Neutron Source(CSNS), transverse painting injection is employed to suppress the space-charge effects. The beta-beating caused by edge focusing of the injection bump magnets leads to tune shift. A new method based on the harmonic injection is firstly introduced to correct the time-dependent tune shift caused by the edge focusing effect of the chicane bump magnets in RCS. The simulation study was done on the application of the new method to the CSNS/RCS, and the results show the validity and effectiveness of the method.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB224  
About • paper received ※ 19 May 2021       paper accepted ※ 16 July 2021       issue date ※ 10 August 2021  
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THPAB243 Optimizing Mu2e Spill Regulation System Algorithms 4281
 
  • A. Narayanan
    Northern Illinois University, DeKalb, Illinois, USA
  • K.J. Hazelwood, M.A. Ibrahim, V.P. Nagaslaev, D.J. Nicklaus, P.S. Prieto, B.A. Schupbach, K. Seiya, R.M. Thurman-Keup, N.V. Tran
    Fermilab, Batavia, Illinois, USA
  • H. Liu, S. Memik, R. Shi, M. Thieme
    Northwestern University, Evanston, Illinois, USA
  
  Funding: The work has been performed at Fermilab. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE-AC02-07CH11359.
A slow extraction system is being developed for the Fermilab’s Delivery Ring to deliver protons to the Mu2e experiment. During the extraction, the beam on target experiences small intensity variations owing to many factors. Various adaptive learning algorithms will be employed for beam regulation to achieve the required spill quality. We discuss here preliminary results of the slow and fast regulation algorithms validation through the computer simulations before their implementation in the FPGA. Particle tracking with sextupole resonance was used to determine the fine shape of the spill profile. Fast semi-analytical simulation schemes and Machine Learning models were used to optimize the fast regulation loop. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB243  
About • paper received ※ 20 May 2021       paper accepted ※ 28 July 2021       issue date ※ 20 August 2021  
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THPAB244 Design of Interdigital H-Mode Re-Buncher at KoBRA Beamline 4285
 
  • Y. Lee, E.-S. Kim
    KUS, Sejong, Republic of Korea
  
  KOrea Broad acceptance Recoil spectrometer & Apparatus (KOBRA) is an experimental facility for low energy nuclear physics in the heavy ion accelerator complex RAON. Two re-buncher systems at KOBRA beamline are required to longitudinally focus the 40Ar9+ with 27MeV/u. The normal conducting IH resonator with seven-gap as the re-buncher structure was chosen because of the reduction in the risk of particulate contamination and total power consumption. In this paper, the detailed design results of the 162.5 MHz IH re-buncher cavity will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB244  
About • paper received ※ 19 May 2021       paper accepted ※ 27 July 2021       issue date ※ 24 August 2021  
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