IPAC2019 - List of Keywords (lattice)

Paper	Title	Other Keywords	Page
MOPGW006	Long Range Beam Beam: Towards Faster Computations	optics, interaction-region, closed-orbit, betatron	72
	S.R. Koscielniak TRIUMF, Vancouver, Canada
	We outline some features of a program of study toward faster computation of the cumulative effect of a sequence of beam-beam interactions across the interaction region.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW006
About •	paper received ※ 23 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW007	Electromagnetic Impulse of Beam Density F(x, y)G(z)	factory, site, storage-ring, interaction-region	75
	S.R. Koscielniak TRIUMF, Vancouver, Canada
	We calculate the transverse impulse on a test particle as a bunch of charged particles beam passes by. It is often assumed, but seldom proven, that the EM field from a beam density distribution factored into transverse and longitudinal parts, F and G respectively, has also a factored form P(x, y)Q(z). This factorization is not possible for stationary charges. Contrastingly, it becomes increasingly accurate for ultra-relativistic particle beams. We give a general analysis, show how to develop the corrections in terms of integrals of F and derivatives of G. What is significant is that if we integrate over longitudinal coordinate z to find the transverse impulse on a witness charge, the correction terms integrate to zero leading to the impulse P(x, y)Integral[Q(z)] independent of bunch shape. If this result is already known, this paper serves as a reminder.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW007
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPGW014	Developing Beam Optics for the BESSY VSR Project	optics, quadrupole, storage-ring, cavity	94
	F. Andreas, M. Abo-Bakr, F. Armborst, P. Goslawski HZB, Berlin, Germany
	At BESSY II due to the continuously increasing interest in short pulse operation, a major upgrade of the ring will enable simultaneous storage of long and short bunches. This Variable pulse-length Storage Ring (VSR) will be achieved by the installation of additional superconducting high gradient cavities. The cavities will be assembled into one cryomodule in one of the straights of the storage ring. As this module needs more space then initially assumed, one possible solution is to remove two quadrupoles to gain available installation length. The quadrupoles were switched off in simulations and the lattice was optimized with regard to the linear order. The best solution found was transferred to the storage ring, where storage of high current with reasonable injection efficiency and lifetime was possible. The proposed optics has to be further optimized in terms of nonlinear beam dynamics, but has shown that an available installation length can be increased.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW014
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW019	Beam-Beam Blowup Issue After Low Emittance Tuning for FCC-ee	emittance, simulation, optics, coupling	112
	D. El Khechen, K. Oide, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW019
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW023	An Algorithm for Automated Lattice Design of Transfer Lines	quadrupole, focusing, dipole, target	127
	S. Reimann, M. Droba, O. Meusel, H. Podlech IAP, Frankfurt am Main, Germany
	Since the last 20 years, modern heuristic algorithms and machine learning have been increasingly used for several purposes in accelerator technology and physics. Since computing power has become less and less of a limiting factor, these tools have become part of the physicist community’s standard toolkit. This paper describes the construction of an algorithm that can be used to generate an optimised lattice design for transfer lines under the consideration of restrictions that usually limit design options in reality. The developed algorithm has been applied to the existing SIS18 to HADES transfer line in GSI.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW023
About •	paper received ※ 28 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPGW029	Preliminary Study of Bunch Compression in the Hefei Light Source	storage-ring, radiation, electron, synchrotron-radiation	151
	W. Li, Z.H. Bai, W. Li, J.G. Wang, D.R. Xu, Z. Zhao USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077), and the National Natural Science Foundation of China(GrantNo.11475167). Short electron bunch has interesting applications in the synchrotron radiation light sources, such as the production of powerful coherent THz radiation, time resolving spectrum analysis, etc. In this work, we are interested in acquiring the short bunch in the storage ring with a small circumference like Hefei Light Source. In this paper, we tried to approach the short bunch in two separate methods: by increasing the higher harmonic cavity voltage and by reducing the momentum compaction factor. The preliminary result and observations are shown and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW029
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW040	Beam Optics Design of the Superconducting Region of the JAEA ADS	emittance, linac, cavity, controls	181
	B. Yee-Rendón, Y. Kondo, F.M. Maekawa, S.I. Meigo, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	The Japan Atomic Energy Agency (JAEA) is proposing an Accelerator Driven Subcritical System (ADS) for the transmutation of the nuclear waste. ADS will consist of a superconducting CW proton linear accelerator of 30MW and a subcritical nuclear reactor core. The main part of the acceleration will take part in the superconducting region using five types of radio frequency cavities. The ADS operation demands a high intensity and reliability of the beam. Therefore, the beam optics design plays a fundamental role to reduce the beam loss, control emittance growth and beam halo.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW040
About •	paper received ※ 17 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW044	Off-Energy Off-Axis Injection with Pulsed Multipole Magnet Into the HALS Storage Ring	injection, storage-ring, kicker, multipole	187
	G. Liu, Z.H. Bai, W. Li, L. Wang, P.N. Wang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	As a future Diffraction-Limited Storage Ring (DLSR) at NSRL, the Hefei Advanced Light Source (HALS) has been proposed and has a great progress in the lattice optimization. The nonlinear dynamics is well designed and shows good performance, which makes it easier for beam injection and gives us more choices to design a more suitable injection scheme. In this paper, a new off-energy off-axis pulsed multipole injection scheme is proposed. The off-energy beam is off-axis injected into the acceptance of the storage ring with one or several pulsed multipole kickers and meanwhile the stored beam is almost unaffected during the injection. The injection acceptance of the storage ring is analyzed and the injection scheme is preliminary designed. A series of tracking simulations are carried out and the results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW044
About •	paper received ※ 15 May 2019 paper accepted ※ 17 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, sextupole, dynamic-aperture	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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MOPGW052	The Study of Single-Bunch Instabilities in the Ramping Process in the HEPS Booster	booster, impedance, simulation, injection	206
	H.S. Xu, Y.M. Peng, N. Wang IHEP, Beijing, People’s Republic of China
	The booster of High Energy Photon Source (HEPS) is proposed to ramp the beam energy from 500 MeV to 6 GeV, and to deliver the required charge to the storage ring. However, the transverse single-bunch instability may limit the reachable bunch charge in the booster. The study of the transverse single-bunch instability has been carried out for the HEPS booster at both 500 MeV and 6 GeV to double check whether the required single-bunch charge can be achieved. Furthermore, the energy ramping process was recently included in the study. We concentrate in the analyses of the simulation results with the consideration of energy ramping process in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW052
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW062	Radiation of a Charge Moving in a Wire Structure	radiation, FEL, simulation, electron	231
	S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev Saint Petersburg State University, Saint Petersburg, Russia A.I. Benediktovitch EuXFEL, Hamburg, Germany A.I. Benediktovitch BSU, Minsk, Belarus, Belarus
	Funding: This work is supported by the grant from Russian Foundation for Basic Research (No. 17-52-04107). In the X-ray frequency region, interaction of relativistic electrons with crystals results in parametric X-ray radiation (PXR), with its frequency being determined by distance between crystallographic planes and direction of electron motion. If instead of crystal one considers an artificial periodic structure with periods of the order of mm, one can expect emission of radiation of a similar nature at terahertz (THz) frequencies. This frequency range is of significant interest during last decade due to its prospective applications. Moreover, artificial wire-like structures are considered as a promising alternative to conventional dielectric structures for wakefield acceleration. Here we consider electromagnetic (EM) field produced by a charged particle bunch moving through a lattice of parallel conducting wires. We present several approaches for analysis of EM field in the described wire structure. First, conventional two-wave approximation for describing the "short-wave response" is developed. Second, we use the effective medium approach and describe the "long-wave" part of the spectrum. Third, we develop a method based on vibrator antenna theory which can be useful for finite length wire structure. P.D. Hoang, et al., Phys. Rev. Lett., V. 120, P. 164801 (2018).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW062
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW063	Beam Dynamics Optimization in Drift Tube Linear Accelerator With Permanent Quadrupole Magnets	rfq, quadrupole, cavity, DTL	234
	I. Skudnova Saint Petersburg State University, Saint Petersburg, Russia
	The research concerns the design of a drift tube linear accelerator (DTL) with permanent quadrupole magnets (PMQ) placed inside some of the drift tubes for focusing. The study was conducted using Comsol Multiphysics software, where electromagnetic fields and particle dy-namics in the cavity were calculated. The proton beam is accelerated up to 10 MeV. Initial beam is assumed to come from Radio Frequency Quadrupole accelerator (RFQ). Mathematical methods of control theory are used for particles dynamics optimization. Different focusing lattices are examined and variations of the gradient of the magnetic lenses are analyzed with respect to output beam parameters. Effectiveness of the optimization is estimated by the transmission rate and the emittance growth.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW063
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW090	Alignment of a Magnetic Lattice Based on Particle Tracking	alignment, optics, controls, sextupole	324
	K.P. Nesteruk, C. Calzolaio, J.M. Schippers PSI, Villigen PSI, Switzerland
	In calculations based on particle tracking in 3D magnetic field maps alignment of the components of a magnetic lattice is essential to obtain desired properties of beam optics. In this contribution we propose a method to control and correct misalignments during the process of the beam optics design. These misalignments would result from overlapping fringe fields of different field maps. The 3D field maps are obtained from the software for electromagnetic calculations OPERA. The full 3D map is saved in the tracking coordinate system and a ROOT (An Object Oriented Data Analysis Framework) ntuple is then created for analysis. The trajectory of the reference particle is calculated by means of OPAL - open source code developed at the Paul Scherrer Institut (PSI). The transverse magnetic field profiles allow possible misalignments to be precisely determined and the corresponding corrections to be calculated. Moreover, the multipole content in discrete locations along the lattice can be controlled by performing a polynomial fit, which calculates the magnetic field harmonics with respect to the reference track. This method was used at PSI for a design of a model of the magnetic lattice for a superconducting gantry for proton therapy with a large momentum acceptance. *An Object Oriented Data Analysis Framework - http://root.cern.ch
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW090
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW093	Optics Calibration for Routine Operations In Taiwan Photon Source	optics, quadrupole, operation, coupling	335
	F.H. Tseng, C.H. Chen, P.J. Chou NSRRC, Hsinchu, Taiwan
	To ensure a stable performance of Taiwan Photon Source (TPS), we perform the calibration of accelerator optics using LOCO (Linear Optics from Closed Orbit) technique every month. After the optics and coupling corrections, the rms beta beatings in both planes are reduced to less than 1%. The emittance coupling ratio is also restored to within the design value.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW093
About •	paper received ※ 06 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPGW096	Beam Dynamics in MBA Lattices with Different Chromaticity Correction Schemes	sextupole, emittance, betatron, storage-ring	346
	L. Hoummi, J. Resta-López, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom L. Hoummi, J. Resta-López, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom A. Loulergue, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	Ultra-low emittance lattices are being studied for the future upgrade of the 2.75 GeV SOLEIL storage ring. The candidate baseline lattice was inspired by the ESRF-EBS-type Multi-Bend-Achromat (MBA) lattice, introducing a (-I) transformation to compensate the nonlinear impact of sextupoles thanks to the lattice symmetry and tight control of the betatron phase advance between sextupoles. Whilst the final performance is still being optimized, other types of lattices are being considered for SOLEIL: This includes the so-called High-Order Achromat (HOA) lattice. Though the (-I) scheme provides a large on-momentum transverse dynamic aperture in 4D, its off-momentum performance is rather limited. 6D studies reveal intrinsic off-momentum transverse oscillations which are likely to result from a nonlinear increase in path length. This contribution presents the effects from the inhomogeneous sextupole distribution in the (-I) scheme and compares them with the HOA lattice.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW096
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW097	SOLEIL Storage Ring Upgrade Performance in Presence of Lattice Imperfections	quadrupole, sextupole, closed-orbit, dipole	350
	A. Vivoli, A. Bence, P. Brunelle, A. Gamelin, L. Hoummi, A. Loulergue, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	The design for the upgrade of the SOLEIL third generation light source is progressing. At the present stage, different lattices are evaluated as possible candidates for the storage ring upgrade and an important factor for the comparison of their performances is the robustness against lattice imperfections. The strategy for this study consists in defining a set of misalignments of the lattice elements and field errors of the magnets that are expected to be attained after the commissioning, applying them to the lattice models and correcting them using response matrix based techniques. A dedicated algorithm was developed in Accelerator Toolbox in order to accomplish this procedure and compare the different lattices. In this paper the results of this study at the current state are presented, including the considered lattice imperfections, the correction method applied and the final performance of the lattices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW097
About •	paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPGW098	Iterative Trajectory-Correction Scheme for the Early Commissioning of Diffraction-Limited Light Sources	MMI, feedback, simulation, storage-ring	353
	Ph. Amstutz, T. Hellert LBNL, Berkeley, USA
	The commissioning of diffraction-limited light sources will be significantly affected by the fact that typical lattice designs rely on very strong focussing elements in order to achieve the small emittance goals. Especially in the early-commissioning phase this can render procedures successfully used in the commissioning of existing third-generation light sources ill-suited for the application to these new machines. In this contribution we discuss an iterative approach to the early trajectory correction, based on the well-known pseudo-inversion of a trajectory-response matrix. Measuring this matrix during early commissioning can be cumbersome, so that an algorithm working with the model response matrix of the lattice is desirable. We discuss the stability of the iteration in the presence of lattice errors, resulting in differences between the actual and the model response matrix. Further, Tikhonov regularization is investigated as a means to trade off the RMS trajectory variation against the strength of the required corrector kicks.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW098
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW105	Preliminary Lattice Studies for the Single-Invariant Optics Experiment at the University of Maryland	experiment, octupole, optics, resonance	367
	L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, I. Haber, D.B. Matthew UMD, College Park, Maryland, USA K.J. Ruisard ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is supported through DOE-HEP Award DESC0010301 and NSF Award PHY1414681. A novel approach to transverse resonance suppression in next generation high-intensity accelerators is the use of nonlinear optical elements to induce large tune spreads which result in reduced responses to resonance driving perturbations. In order to test this theory, we have built and characterized an octupole channel insert for use in the University of Maryland Electron Ring (UMER). This paper presents experimental lattice studies using a low space-charge intensity beam at an energy of 10keV with a beam current of ~150uA, tune depression < 0.005, and unnormalized RMS emittance of 4.3 mm-mr. We apply beam based measurement techniques in order to evaluate the quality of our single-invariant lattice and better understand the nonlinearities created by the octupole channel. V. Danilov and S. Nagaitsev, Nonlinear accelerator lattices with one and two analytic invariants, PRSTAB, 13, 084002, 2010.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW105
About •	paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW107	Study of Integrable and Quasi-Integrable Sextupole Lattice	sextupole, resonance, focusing, optics	371
	L. Gupta, Y.K. Kim University of Chicago, Chicago, Illinois, USA S. Baturin Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA S. Nagaitsev Fermilab, Batavia, Illinois, USA
	Funding: Funded through Center for Bright Beams, NSF award PHY-1549132 In order to maximize beam lifetime in circular particle accelerators, the nonlinear beam optics are optimized to maximize the dynamic aperture of the beam. The dynamic aperture (DA), which is a 6-D phase space volume of stable trajectories, depends on the strength of the nonlinearities in the machine, and is calculated via particle tracking. Current DA optimization processes include multi-objective genetic algorithm optimizers, and relies on minimizing the magnitudes of resonance driving terms (RDT), which are calculated from the nonlinear contribution to the one-turn-map. The process of searching through the parameter space for an ideal combination that maximizes DA is computationally strenuous. By setting up the sextupole channel such that it is resembles a symplectic integrator of a smooth Hamiltonian, with only a few sextupoles we are able to closely reproduce phase space trajectories of a smooth Hamiltonian up to the hyperbolic point. No chaos and resonances are observed if phase advance per one sextupole magnet in the channel does not exceed ~0.12x2 pi. Therefore, an important property of the suggested approach is the intrinsic elimination of the resonances, and minimization of corresponding RDTs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW107
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW110	Study of the Beam Current Effects on the NSLS-II Storage Ring Optics Using Turn-by-Turn Data	optics, storage-ring, dipole, operation	375
	J. Choi, Y. Hidaka BNL, Upton, Long Island, New York, USA
	These days, the techniques using the turn-by-turn data are well developed in analyzing the accelerator optics. We compared the data for the low and high beam currents and studied the beam current effects on the storage ring lattice optics. Also, by comparing the local transfer matrices, we analyzed the amounts of the impacts on the linear optics around the ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW110
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW113	Experimental Demonstration of the Henon-Heiles Quasi-Integrable System at IOTA	octupole, experiment, optics, alignment	386
	N. Kuklev, Y.K. Kim University of Chicago, Chicago, Illinois, USA S. Nagaitsev, A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy. The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report the first results of experimental investigation of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread and dynamic aperture preservation. Resilience to perturbations and imperfections in the lattice is explored. We conclude by outlining future research plans and discussing applicability to future high intensity accelerators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW113
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPGW114	Bayesian Approach for Linear Optics Correction	quadrupole, optics, GUI, distributed	390
	Y. Li, W.X. Cheng, R.S. Rainer BNL, Upton, Long Island, New York, USA
	With a Bayesian approach, the linear optics correction algorithm for storage rings is revisited. In modern ring-based accelerators, optics corrections are determined from repetitive measurements which help identify systematic and random quadrupole errors in presence of various measurement noises. This process is a multivariate nonlinear regression problem driven by either a completed lattice model or a Jacobian matrix. Starting from the Bayes’ theorem, ’likelihood functions’ and ’prior probability’ distributions are extracted from a complete linear optics model. Under some assumptions, the least square algorithm and then the Jacobian matrix approach can be re-derived. The coherence of the correction algorithm is ensured through specifying a self-consistent regularization coefficient to prevent overfitting. Optimal weights for different correction objectives are obtained based on their measurement noise level. A new technique has been developed to resolve degenerated quadrupole errors when observed at a few select BPMs. A necessary condition of being distinguishable is that their optics response vectors seen at these specific BPMs should be near-orthogonal.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW114
About •	paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW115	A Cross-Cell Interleaved Nonlinear Lattice for Potential NSLS-II Upgrade	emittance, sextupole, optics, dynamic-aperture	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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MOPGW124	Coherent Synchrotron Radiation Simulation for CBETA	simulation, linac, radiation, shielding	406
	W. Lou, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes SLAC, Menlo Park, California, USA N. Tsoupas BNL, Upton, Long Island, New York, USA
	CBETA is an energy recovery linac accelerating from 6 MeV to 150 MeV in four linac passes, using a single return beamline accepting all energies from 42 to 150 MeV. While CBETA gives promise to deliver unprecedentedly high beam current with simultaneously small emittance, Coherent Synchrotron Radiation (CSR) can pose detrimental effect on the beam at high bunch charges and short bunch lengths. To investigate the CSR effects on CBETA, we used the established simulation code Bmad to track a bunch with different parameters. We found that CSR causes phase space dilution, and the effect becomes more significant as the bunch charge and recirculation pass increase. Potential ways to mitigate the effect involving vacuum chamber shielding and increasing bunch length are being investigated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW124
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW125	Lossless Crossing of 1/2 Resonance Stopband by Synchrotron Oscillations	resonance, experiment, betatron, storage-ring	410
	G.M. Wang, Y. Li, J. Rose, T.V. Shaftan, V.V. Smaluk BNL, Upton, Long Island, New York, USA
	Funding: DOE under contract No.DE-AC02- 98CH10886 Modern high performance circular accelerators require sophisticated corrections of nonlinear lattices. The beam betatron tune footprint may cross many resonances, reducing dynamic aperture and causing particle loss. However, if particles cross a resonance reasonably fast, the beam deterioration may be minimized. In this paper, we present the experiments with the beam passing through a half-integer resonance stopband via chromatic tune modulation by exciting synchrotron oscillations. This is the first time that beam dynamics have been kept under precise control while the beam crosses a half-integer resonance. Our results convincingly demonstrate that particles can cross the half-integer resonance without being lost if the passage is reasonably fast and the resonance stopband is sufficiently narrow.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW125
About •	paper received ※ 13 May 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, dynamic-aperture, 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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MOPMP026	HE-LHC Optics Design Options	dipole, quadrupole, hadron, optics	492
	J. Keintzel, M.P. Crouch, M. Hofer, T. Risselada, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland M. Hofer, J. Keintzel TU Vienna, Wien, Austria L. van Riesen-Haupt University of Oxford, Oxford, United Kingdom L. van Riesen-Haupt JAI, Oxford, United Kingdom
	The High Energy Large Hadron Collider (HE-LHC), a possible successor of the High Luminosity Large Hadron Collider (HL-LHC) aims at reaching a centre-of-mass energy of about 27 TeV using basically the same 16 T dipoles as for the hadron-hadron Future Circular Collider FCC-hh. Designing the HE-LHC results in a trade off between energy reach, beam stay clear as well as geometry offset with respect to the LHC. In order to best meet the requirements, various arc cell and dispersion suppressor options have been generated and analysed, before concluding on two baseline options, which are presented in this paper. Merits of each design are highlighted and possible solutions for beam stay clear minima are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP026
About •	paper received ※ 02 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB001	Low Emittance Tuning of FCC-ee	emittance, coupling, quadrupole, sextupole	574
	T.K. Charles The University of Melbourne, Melbourne, Victoria, Australia S. Aumon, B.J. Holzer, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	The FCC-ee project studies the design of a future 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁶ cm^-2s^-1. In order to reach these luminosity requirements, extreme focusing is needed in the interaction regions. For the Z energy (45.6 GeV) lattice, the maximum beta value is 8322 m, and the vertical beta function is 0.8 mm at the IP. These aspects of the FCC-ee lattice make it particularly susceptible to misalignments and field errors, and therefore present an appreciable challenge for emittance tuning. A challenging correction scheme is proposed to reduce the coupling and the vertical emittance. We describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes special programs, that had been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. Thousands of misalignment and field error random seeds were introduced in MADX simulations and the final corrected lattices are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB001
About •	paper received ※ 09 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPRB003	Multi-Target Lattice for Muon Production From e⁺ Beam Annihilation on Target	target, positron, emittance, site	578
	O.R. Blanco-García LAL, Orsay, France M. Antonelli, M.E. Biagini, M. Boscolo, A. Ciarma, S. Guiducci, C. Vaccarezza, A. Variola INFN/LNF, Frascati, Italy G. Cesarini INFN-Roma, Roma, Italy F. Collamati INFN-Roma1, Rome, Italy R. Li Voti Sapienza University of Rome, Rome, Italy P. Raimondi ESRF, Grenoble, France
	The Low Emittance Muon Accelerator~(LEMMA) aims at producing small emittance muons from positron annihilation with electrons in a target. Given the low cross section of the production process, a large number of positrons on the target are required, exposing it to high power deposition and the beam to large degradation because of multiple scattering and bremstrahlung. A multi-target IP, and multi-IP line has been studied to reduce the power deposition per target and the degradation of the positron beam while preserving the number of muon pairs produced. The lattice copes with the focusing and transport of three beams at two different energies, the positron beam at 45 GeV, and µ⁺+ and µ⁻ beams at 22.5~GeV. Studies on the beam dynamics, number of targets, material and thickness of the targets are reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB003
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB005	Study of Higher-Order Achromat Lattice as an Alternative Option for the SOLEIL Storage Ring Upgrade	sextupole, storage-ring, octupole, injection	586
	R. Nagaoka, A. Bence, P. Brunelle, L. Hoummi, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux, A. Vivoli SOLEIL, Gif-sur-Yvette, France A. Gamelin LAL, Orsay, France
	A ring composed of 20 symmetrical 7BA cells in which of a pair of chromaticity correcting sextupoles placed around horizontal dispersion bumps à la ESRF-EBS was developed as a baseline lattice for the SOLEIL storage ring upgrade (presented at IPAC2018). The strict phase relation between the two dispersion bumps provides an efficient way of optimizing the (on-momentum) nonlinear optics with a limited number of sextupoles. As an alternative, a scheme known as Higher-Order Achromat (HOA) develops a MBA (Multi-Bend Achromat) lattice where chromaticity correcting sextupoles are distributed in each M unit cell with a strict phase relation cell-wise such as to cancel basic geometric and chromatic resonance driving terms. The beam dynamics in a 20-fold 7BA HOA ring is compared with those of the baseline lattice, with focus on off-momentum properties such as Touschek lifetime, which are important for medium energy rings like SOLEIL. The robustness against errors, the reduction of the ring symmetry by introducing 4 longer straight sections, as well as a horizontal dispersion bump to cope with longitudinal on-axis injection scheme are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB005
About •	paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB027	Progress of HEPS Accelerator System Design	storage-ring, cavity, booster, vacuum	633
	P. He, J.S. Cao, F.S. Chen, J. Chen, H. Dong, D.Y. He, Y. Jiao, W. Kang, C.H. Li, J.Y. Li, F. Long, H.H. Lu, X. Qi, Q. Qin, H. Qu, J.Q. Wang, G. Xu, J.H. Yue, J. Zhang, J.R. Zhang, P. Zhang IHEP, Beijing, People’s Republic of China
	The 4th generation ring-based light sources, HEPS (High Energy Photon Source) 7BA lattice has been de-veloped at IHEP. This is 6Gev, 200mA machine which has horizontal emittance Ɛh around 60pm.rad to gain the high brilliance photon beam. this compact lattice design bring so many engineering challenges for accelerator magnets, vacuum components, beam diagnotice, etc. This paper will present the noval lattice design and subsystem design progress.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB027
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB062	nuSTORM Decay Ring	quadrupole, resonance, closed-orbit, emittance	716
	J.-B. Lagrange STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom R.B. Appleby, S.C. Tygier UMAN, Manchester, United Kingdom J. Pasternak STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Precise neutrino cross section measurements and search for sterile neutrinos can be done with neutrino beams produced from muons decaying in a storage ring due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a racetrack storage ring, where circulating muon beam would be captured. The storage ring has three options: a FODO solution with large aperture quadrupoles, a racetrack FFA (Fixed Field Alternating gradient) using the recent developments in FFAs and a hybrid solution of the two previous options. Machine parameters, linear optics design and beam dynamics of the hybrid solution are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB062
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB074	Using an Energy Scan to Determine the Tunes and Orbit in the First FFA Girder of CBETA	betatron, linac, cryomodule, MMI	742
	C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg BNL, Upton, Long Island, New York, USA
	This work reports the results of performing a scan of the beam energy performed during the Fractional Arc Test of the CBETA machine, a multi-pass SRF ERL featuring a non-scaling FFA return loop. The FFA arc consists of identical doublets that are designed to have an energy acceptance from 42 to 150 MeV, with a betatron phase advance (i.e., tune) per cell and periodic orbit position that depends on energy. In the CBETA fractional arc test, we transport the beam through 4 such cells (the first girder), and are capable of injecting beam in to the arc with energies as high as 59 MeV. By creating betatron oscillations in the arc, we can compute the phase advance per cell and periodic orbit position as a function of energy within that range. In addition, because the phase advance varies as a function of energy, the computation also provides an estimate of the offsets of the BPMs in that arc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB074
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB076	CBETA Beam Commissioning Results	linac, MMI, permanent-magnet, electron	748
	C.M. Gulliford, N. Banerjee, A.C. Bartnik, I.V. Bazarov, J.A. Crittenden, K.E. Deitrick, A. Galdi, G.H. Hoffstaetter, P. Quigley, K.W. Smolenski Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg, S.J. Brooks, R.J. Michnoff, D. Trbojevic BNL, Upton, Long Island, New York, USA
	We report on the first results of commissioning CBETAwith a fully closed return loop. We repeat much of our early commissioning from the fractional arc test, namely setting up the injection system, calibrating the main linac, and steering the beam through the first splitter line. Most importantly, first results from sending the beam all the way through the FixedField Alternating gradient permanent magnet return arc are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB076
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB092	Symplectic and Exact Tracking of Low Energy 197Au⁷⁸⁺ in the Relativistic Heavy Ion Collider	electron, quadrupole, simulation, storage-ring	791
	Y. Luo, W. Fischer, F. Méot, G. Robert-Demolaize BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In the coming RHIC low energy scan, the electron cooling technique is to be used to cool the ions 197Au⁷⁹⁺ with its energy range between 3.85~GeV/nucleon to 5.75~GeV/nucleon. To overlap the electron beam and the 197Au⁷⁹⁺ beam at the cooling section, a recombination monitor is to be used to detect the maximum flux of 197Au⁷⁸⁺ ions generated in the cooling section. In the previous studies, we tracked 197Au⁷⁸⁺ ions through the RHIC lattice defined with 197Au⁷⁹⁺ with an equivalent momentum deviation. In the article, we explode different symplectic ways to track 197Au⁷⁸⁺ ions exactly. We calculate and compare the trajectories and loss map of 197Au⁷⁸⁺ ions through the RHIC ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB092
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS003	Superconducting LINAC Design Upgrade in View of the 100 MeV MYRRHA Phase I	linac, cavity, cryomodule, emittance	837
	F. Bouly, M.A. Baylac LPSC, Grenoble Cedex, France A. Gatera SCK•CEN, Mol, Belgium D. Uriot CEA-DRF-IRFU, France
	Funding: Part of this work supported by the European Atomic Energy Community (EURATOM) H₂020 Programme under grant agreement n°662186 (MYRTE project). The goal of the MYRRHA project is to demonstrate the technical feasibility of transmutation in a 100 MW Accelerator Driven System (ADS) by building a new flexible irradiation complex at Mol (Belgium). The MYRRHA facility requires a 600 MeV accelerator delivering a maximum proton current of 4 mA in continuous wave operation, with an additional requirement for exceptional reliability. Supported by SCK•CEN and the Belgium government the project has entered in its phase I: which consists in the development and the construction of the linac first part, up to 100 MeV. We review the design updates of the superconducting linac, with its enhanced fault-tolerance capabilities. The linac capabilities at 100 MeV (Phase I) and 600 MeV (ADS operation) are exposed and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS003
About •	paper received ※ 23 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS004	2nd Order Optics Symmetrisation through Off-Energy Orbit Response Matrix Analysis	sextupole, optics, storage-ring, alignment	841
	D.K. Olsson, Å. Andersson, M. Sjöström MAX IV Laboratory, Lund University, Lund, Sweden
	The MAX IV 3 GeV storage ring lattice contains several strong sextupoles. In order to achieve nominal lattice performance it is important to be able to characterise and correct the higher order magnets and optics of the lattice. This has been done through the analysis of the Off-Energy Response Matrix (OEORM). Its approximate linearity in sextupole strength has been utilised to identify sextupole errors, as well as symmetrise the 2nd order optics. The symmetrisation was able to correct chromaticity, and increase horizontal acceptance by 50 %, compared to magnet settings based solely on rotating coil measurements. An approximate decrease of 10 % in vertical acceptance was detected. This work was inspired by similar investigations at ESRF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS004
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS010	Simulation of the Guide Field Flipping Procedure for the Frequency Domain Method	GUI, simulation, sextupole, dipole	858
	A.E. Aksentyev FZJ, Jülich, Germany A.E. Aksentyev MEPhI, Moscow, Russia A.E. Aksentyev, V. Senichev RAS/INR, Moscow, Russia
	The spin vector of a particle injected into a perfectly aligned storage ring precesses about the vertically-orientated guide field. In the presence of an Electric Dipole Moment (EDM), the spin precession axis acquires a proportional radial component. However, in an imperfect ring, rotational magnet misalignments induce a radial component to the spin precession axis, related to the Magnetic Dipole Moment (MDM). In the Frequency Domain Method, [] this additional precession is dealt with by consecutively injecting the beam in opposite directions, and constructing the EDM estimator as the sum of the clockwise and counter-clockwise vertical plane precession frequencies. Since the radial MDM component changes sign when the magnetic field direction is reversed, it cancels in the sum, leaving only the EDM effect. In order to reproduce the guide field magnitude with precision sufficient for the cancellation of the MDM effect, we propose to calibrate the guide field via the horizontal plane precession frequency. In the present work we describe the algorithm of the field flipping procedure, and do a numerical simulation. [] Senichev Y, Aksentev A, Ivanov A, Valetov E. Frequency domain method of the search for the deuteron electric dipole moment in a storage ring with imperfections. arXiv:171106512. 2017 Nov 17.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS010
About •	paper received ※ 08 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS011	Spin Motion Perturbation Effect on the EDM Statistic in the Frequency Domain Method	betatron, polarization, dipole, storage-ring	861
	A.E. Aksentyev FZJ, Jülich, Germany A.E. Aksentyev MEPhI, Moscow, Russia A.E. Aksentyev, V. Senichev RAS/INR, Moscow, Russia
	The spin precession axis of a particle involved in betatron motion precesses about the invariant spin axis defined on the closed orbit (CO). This precession can be observed in polarization data as a rapid, small-amplitude oscillation on top of the major effect oscillation caused by the precession of spin about the CO axis. The frequency of this latter oscillation is used in the Frequency Domain (FD) methodology as the EDM observable. [] It is estimated by fitting polarimetry data by a sine function; the rapid oscillations, therefore, constitute a model specification error. This model error might introduce a bias into the frequency estimate. In the present work we investigate the effect of the spin precession axis motion on measurement data and fit quality, and conclude that it is not only insignificant (with regard to data perturbation) compared to spin tune variation, but is also controllable via the application of a Spin Wheel. [] Senichev Y, Aksentev A, Ivanov A, Valetov E. Frequency domain method of the search for the deuteron electric dipole moment in a storage ring with imperfections. arXiv:171106512. 2017 Nov 17
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS011
About •	paper received ※ 08 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS012	Spin Decoherence in the Frozen Spin Storage Ring Method of Search for a Particle EDM	sextupole, storage-ring, simulation, betatron	864
	A.E. Aksentyev FZJ, Jülich, Germany A.E. Aksentyev MEPhI, Moscow, Russia A.E. Aksentyev, V. Senichev RAS/INR, Moscow, Russia
	Spin coherence refers to a measure of preservation of polarization in an initially polarized beam. The spin vector of a particle injected into a storage ring starts to precess about the vertical magnetic field vector in accordance with the Thomas-BMT equation. The precession frequency is dependent on the equilibrium-level energy, which differs across the beam particles. This does not pose a problem when the initial polarization is vertical; however, the Frozen Spin Storage Ring EDM search method [] requires beam polarization along the momentum vector, i.e., in the horizontal plane. In the present work we analyze the source of decoherence, and investigate the way it can be suppressed in the horizontal plane in a perfectly aligned ring by means of sextupole fields. We also consider the case of an imperfect ring: transference of decoherence into the vertical plane induced by vertical plane spin precession, and the effect of sextupole fields. D. Anastassopoulos et al. AGS Proposal: Search for a permanent electric dipole moment of the deuteron nucleus at the 10 −29 e · cm level. BNL report, 2008.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS012
About •	paper received ※ 08 April 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, dynamic-aperture, 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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MOPTS040	Beta Beating and Coupling Correction of the ILSF Storage Ring	coupling, quadrupole, closed-orbit, alignment	946
	A.M. Mash’al, E. Ahmadi, S. Dastan, J. Rahighi ILSF, Tehran, Iran F.D. Dabbagh Kashani IUST, Narmac, Tehran, Iran
	The Iranian Light Source Facility (ILSF) is a 3 GeV synchrotron radiation facility, which is in the design stage. Inevitable errors like imperfection of magnetic field and misalignment of magnets will introduce various destructive effects on the performance of the machine. The possibility of correcting the errors should be thoroughly examined before settling the design. In this paper, the correction process of beta beating and coupling with LOCO is described. The rms beta beating in horizontal and vertical planes after correction are reduced to 1% and 2% respectively. The average coupling ratio of lattice for 100 random error distribution is corrected to 0.2%.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS040
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUXXPLS3	The Design Optimization of the Dielectric Assist Accelerating Structure for Better Heat and Gas Transfer	cavity, vacuum, multipactoring, embedded	1179
	S. Mori, M. Yoshida KEK, Ibaraki, Japan D. Sato AIST, Tsukuba, Ibaraki, Japan
	The dielectric-assist accelerating (DAA) structure is a dielectric-inserted normal-conducting cavity, which provides high Q value at room temperature. This accelerating structure is composed of dielectric disks and a dielectric cylindrical layer inserted in a copper cavity. For the realistic operation, the removal of heat from the dielectric cells and the vacuum evacuation of gas inside the cylindrical layers have not considered yet. In order to solve the problems, we propose the optimized design of the DAA structure, where the extended part of the dielectric disk is embedded in the copper cavity and the choke structure is applied. We show the result of the electromagnetic-field simulation of the extended DAA structure and the thermal simulation to clarify the relation between a duty factor and maximum temperature of the dielectric cells.
	Slides TUXXPLS3 [5.892 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS3
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUZPLS2	Beam Dynamics Study in the HEPS Storage Ring	storage-ring, emittance, photon, brightness	1203
	Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is the first high-energy diffraction-limited storage ring (DLSR) light source to be built in China, with a natural emittance of a few tens of pm rad and a circumference of 1360.4 m. After 10 years’ evolution, the accelerator physics design of the HEPS has been basically determined, with the ring consisting of 48 hybrid-7BAs with anti-bends and super-bends. This paper will discuss the accelerator physics studies of the HEPS storage ring, covering issues of lattice design, nonlinear optimization, collective effects, error correction, insertion devices, etc.
	Slides TUZPLS2 [9.517 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLS2
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW004	Cls 2.2: Ultra-Brilliant Round Beams Using Pseudo Longitudinal Gradient Bends	quadrupole, injection, emittance, coupling	1385
	L.O. Dallin CLS, Saskatoon, Saskatchewan, Canada
	A preliminary design for a new storage for the Canadian Light Source was presented at IPAC’18 (Dallin). More recently a reconfigured lattice was presented at the 6th DLSR workshop. This lattice employed large βy and small βx in the straights. This has several advantages including: increased transverse coherence and brighter beams at small coupling; round beams at small coupling; flatter βy through the straights; and possible off-axis vertical injection at small amplitudes. Most recently longitudinal gradients in the dipoles have been implemented. This has lead to the unit cell bends being replaced by a ’pseudo longitudinal gradient’ bend array: bend1-bend2-bend1. This results in smaller emittance with simple magnet designs while maintaining adequate dynamic aperture for off-axis injection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW004
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW011	Status of the PETRA IV project	emittance, brightness, timing, synchrotron	1404
	I.V. Agapov, R. Bacher, M. Bieler, R. Bospflug, R. Brinkmann, Y.-C. Chae, H.C. Chao, H.T. Duhme, M. Ebert, H.-J. Eckoldt, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, U. Hurdelbrink, J. Keil, J. Klute, M. Körfer, B. Krause, G. Kube, W. Leemans, L. Lilje, F. Obier, A. Petrov, N. Plambeck, J. Prenting, G.K. Sahoo, H. Schlarb, M. Schlösser, F. Schmidt-Föhre, M. Schmitz, C.G. Schroer, T. Tempel, M. Thede, M. Tischer, R. Wanzenberg, E.F. Weckert, T. Wilksen, K. Wittenburg, J.X. Zhang DESY, Hamburg, Germany
	Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW011
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW016	New Operation Regimes at the Storage Ring KARA at KIT	optics, operation, injection, simulation	1422
	A.I. Papash, E. Blomley, T. Boltz, M. Brosi, E. Bründermann, S. Casalbuoni, J. Gethmann, E. Huttel, B. Kehrer, A. Mochihashi, A.-S. Müller, R. Ruprecht, M. Schuh, J.L. Steinmann KIT, Karlsruhe, Germany
	The storage ring Karlsruhe Research Accelerator (KARA) at KIT operates in a wide energy range from 0.5 to 2.5 GeV. Initially, the ring was designed to serve as a Light Source for synchrotron radiation facility ANKA. Since then different operation modes have been implemented at KARA: in particular, the double bend achromat (DBA) lattice with non-dispersive straight sections, the theoretical minimum emittance (TME) lattice with distributed dispersion, and different versions of low compaction factor optics with highly stretched dispersion function. Short bunches of a few ps pulse width are available at KARA. Low alpha optics have been tested and implemented in a wide operational range of the ring and are now routinely used at 1.3 GeV for studies of CSR-induced beam dynamics and THz bursting in the micro-bunching instability. Different non-linear effects, in particular, residual high order components of magnetic fields generated in insertion devices have been studied and cured. A new operation mode at high vertical tune implemented at KARA essentially improves beam performance during user operation as well as at low alpha regimes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW016
About •	paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW018	PETRA IV Study with Non-Interleaved Sextupole Scheme	sextupole, emittance, storage-ring, optics	1430
	H.C. Chao, R. Brinkmann, X.N. Gavaldà DESY, Hamburg, Germany
	This study is an attempt to design PETRA IV storage ring, which is an upgrade from PETRA III toward diffraction-limit synchrotron light source, based on the non-interleaved sextupole scheme. The lattice is constructed by mixing different types of cells. There are two basic building blocks. The double minus identity (DMI) cell dedicated for the chromaticity correction with non-interleaved sextupoles is tightly built up, while the combined function FODO cell with dispersion suppressors provides straights with small beta functions ideally for undulators. In addition, the hybrid section including a 10-m long super insertion device (ID) is custom-made to adapt to DESY’s current site plan. The beam dynamic behaviors are simulated and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW018
About •	paper received ※ 18 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW020	Non-Linear Features of the cSTART Project	storage-ring, quadrupole, sextupole, injection	1437
	B. Härer, E. Bründermann, A.B. Kaiser, A.-S. Müller, A.I. Papash, R. Ruprecht, J.M. Schaefer, M. Schuh KIT, Karlsruhe, Germany
	The compact storage ring for accelerator research and technology (cSTART) is being designed and will be realized at the Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT). One important goal of the project is to demonstrate injection and storage of a laser wakefield accelerator (LWFA) beam in a storage ring. As a first stage the compact linear accelerator FLUTE will serve as an injector of 50 MeV bunches to test the ring’s performance. A highly non-linear lattice of DBA-FDF type was studied extensively. The specific features of ring optics are reported. A special transfer line from FLUTE to cSTART including bunch compressor and non-linear elements is presented that maintains the ultra-short bunch length of FLUTE.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW020
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW021	An Accelerator Toolbox (AT) Utility for Simulating the Commissioning of Storage-Rings	MMI, simulation, injection, alignment	1441
	T. Hellert, Ph. Amstutz, C. Steier, M. Venturini LBNL, Berkeley, California, USA
	We present the development of an AT-based toolkit, which allows for realistic commissioning simulations of storage ring light sources by taking into account a multitude of error sources as well as diligently treating beam diagnostic limitations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW021
About •	paper received ※ 08 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPGW022	Commissioning Simulation Study for the Accumulator Ring of the Advanced Light Source Upgrade	MMI, injection, quadrupole, simulation	1445
	T. Hellert, Ph. Amstutz, M.P. Ehrlichman, S.C. Leemann, C. Steier, C. Sun, M. Venturini LBNL, Berkeley, California, USA
	The Advanced Light Source Upgrade (ALS-U) to a diffraction-limited soft x-rays light source requires the construction of an Accumulator Ring (AR) to enable swap-out, on-axis injection. The AR lattice is a Triple-Bend-Achromat lattice similar to that of the current ALS but to minimize the magnet sizes the vacuum chamber will be significantly narrower hence requiring a careful evaluation of the magnets’ field quality. This work presents the results of a detailed error tolerance study including a complete simulation of the commissioning process.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW022
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW039	Error Study and Correction of Hefei Advanced Light Source	optics, quadrupole, closed-orbit, coupling	1492
	D.R. Xu, Z.H. Bai, W. Li USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Hefei Advanced Light Source (HALS) is a future diffraction limited storage ring. The machine performance under all kinds of magnet errors is a vital component in physical design. In this paper, we present our work on the closed orbit correction, the linear beam optics compensation and the coupling control in HALS. After correction, the dynamical aperture can suffice the injection scheme.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW039
About •	paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW040	Study of Seven-Bend Achromat Lattices with Interleaved Dispersion Bumps for HALS	storage-ring, emittance, octupole, linear-dynamics	1495
	Z.H. Bai, W. Li, G. Liu, L. Wang, D.R. Xu, T. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Previously, we proposed a multi-bend achromat (MBA) lattice concept, called the MBA with interleav-ed dispersion bumps, which was then used to design a 7BA lattice for the Hefei Advanced Light Source (HALS) storage ring. Recently, such a 7BA lattice was further designed and optimized for the HALS by changing the number of lattice cells, scanning working point and employing octupoles. And two new HALS designs with such 7BA lattices have been made, one with 30 lattice cells and a natural emittance of 25 pm·rad and the other with 28 cells and 33 pm·rad. They had much better nonlinear dynamics perfor-mances than the previous design. The detailed study for these two HALS lattices will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW040
About •	paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPGW041	Super-Period Locally Symmetric Lattices for Designing Diffraction-Limited Storage Rings	storage-ring, emittance, sextupole, quadrupole	1498
	Z.H. Bai, W. Li, G. Liu, L. Wang USTC/NSRL, Hefei, Anhui, People’s Republic of China Y. Li BNL, Upton, Long Island, New York, USA
	To achieve better nonlinear dynamics performance for a diffraction-limited storage ring, previously we proposed a locally symmetric multi-bend-achromat (MBA) lattice concept, where beta functions are locally symmetric about two mirror planes of each lattice cell. To have both high-beta long straight sections for beam injection and low-beta ones for higher brightness of insertion device radiation, many storage ring light sources use super-period lattices. The locally symmetric MBA lattice can be naturally extended to the super-period case. In the super-period locally symmetric (SP-LS) lattice, many nonlinear dynamics effects can be effectively cancelled out within one super-period lattice cell, and also there are many knobs to be used for further nonlinear optimization. As examples, two SP-LS lattices have been designed towards diffraction-limited emittances.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW041
About •	paper received ※ 20 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW042	Study of the Intra-beam Scattering Effects in the HALS Storage Ring	emittance, damping, wiggler, storage-ring	1501
	W. Li, Z.H. Bai, W. Li, D.R. Xu, T. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077). The Hefei Advanced Light Source (HALS) is designed to be a dedicated 4th generation diffraction limited light source. In 2018, the baseline lattice of the HALS storage ring has been proposed, with an ultra-low natural emittance of about 25 pm-rad. The preliminary study of intra-beam scattering effects on the beam emittance growth in the HALS storage ring has been performed with this baseline lattice. Due to the limited synchrotron radiation in this storage ring, damping wigglers are expected in this storage ring to reduce the damping time and reduce the emittance. In this paper, we will present the simulation results of the IBS effects, estimated effectiveness of damping wiggler and the corresponding linear optics calibration of the perturbation due to insertion device, and finally the estimated Touschek lifetime will be shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW042
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW046	Progress of Lattice Design and Physics Studies on the High Energy Photon Source	storage-ring, booster, photon, injection	1510
	Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is an ul-tralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physics design and related studies of HEPS over the past year, covering issues in storage ring lattice design, injection and injector design, insertion device effects, error study and lattice calibration, collective effects, etc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW046
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW052	STUDY OF THE RAMPING PROCESS FOR HEPS BOOSTER	booster, storage-ring, damping, injection	1521
	Y.M. Peng, J.Y. Li, C. Meng, H.S. Xu IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is a 6-GeV, ul-tralow-emittance storage ring light source to be built in Huairou District, Beijing, China. The beam energy ramps from 500 MeV to 6 GeV in 400 ms, during which the RF voltage increases accordingly to keep the momentum acceptance large enough. The booster is designed to operate at 1 Hz repetition frequency. In this paper the energy ramping curve, RF choice, beam parameters changing curves and eddy current effect in HEPS booster will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW052
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW053	Simulations of the Injection Transient Instabilities for the High Energy Photon Source	injection, feedback, simulation, storage-ring	1524
	Z. Duan, N. Wang, H.S. Xu IHEP, Beijing, People’s Republic of China
	Funding: Work supported by Natural Science Foundation of China (No.11605212). A "charge recovery in booster" scheme* was proposed to deliver the full charge bunches for the swap-out injection of the High Energy Photon Source. In this scheme, the booster is employed also as a full energy accumulator ring to capture the high charge bunch extracted from the storage ring via merging with the small charge bunch accelerated in the booster, after enough damping in the booster for about 20 ms, the recovered full charge bunch is re-injected into the storage ring. This scheme avoids the challenges to accelerate a bunch charge of ~ 15 nC, and is cost effective compared to building a dedicated 6 GeV accumulator ring. However, there will be a period of time during injection that one bunch is missing in the storage ring, which inevitably introduces some injection transients. Since "transparency" to the user experiments is a desired feature of injection schemes for next generation diffraction-limited storage rings, the injection transient effects are simulated for the proposed injection scheme, and how it would affect the user experiments are carefully evaluated. * Z. Duan, et al., "The swap-out injection scheme for the High Energy Photon Source", Proc. IPAC’18, THPMF052
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW053
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW054	Design of a Hybrid Seven-Bend-Achromat Lattice for a High-Energy Diffraction-Limited Storage Ring Using a New Optimization Method	linear-dynamics, emittance, optics, sextupole	1528
	P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Recently, we proposed a new optimization method, with nonlinear dynamics indicators considered in the linear optics design, for designing hybrid multi-bend-achromat (MBA) lattices. With this method, two hybrid MBA lattices for medium-low-energy diffraction limited storage rings (DLSRs) have been designed, showing remarkable effectiveness in improving nonlinear dynamic performance. In this paper, we will apply this optimization method to the design of a hybrid 7BA lattice for a 6 GeV DLSR with the same circumference as that of HEPS. In the design, the strengths and arrangement of magnets of this lattice also meet the engineering requirement for HEPS. The designed lattice has a natural emittance of 34 pm·rad. The nonlinear dynamic performance is satisfactory, with a dynamic aperture of about 6 mm and 3 mm in the horizontal and vertical directions, respectively, and a dynamic momentum aperture of larger than 5%, which also shows the power of our optimization method.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW054
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW055	Comparison of Optimization Methods for Hybrid Seven-Bend-Achromat Lattice Design	linear-dynamics, sextupole, optics, emittance	1532
	P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Generally, for a hybrid multi-bend-achromat (MBA) lattice with fixed linear optics, there is little potential to further optimize the nonlinear dynamics due to limited free knobs. To obtain a hybrid MBA lattice with better nonlinear dynamics performance, it is better to consider some indicators of nonlinear dynamics as objective functions in designing the linear optics using an optimization algorithm. In this paper, integral strengths of sextupoles and natural chromaticities are used as the nonlinear dynamics indicators, and different optimization methods with both or either of the two indicators are carried out and compared. As an example, a hybrid 7BA lattice with an energy of 2.4 GeV is designed towards an emittance of less than 70 pm·rad.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW055
About •	paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW056	Comparison of Constrained Optimization Methods for Designing a Multi-Bend Achromat Lattice	emittance, sextupole, storage-ring, linear-dynamics	1535
	J.H. Xu, Z.H. Bai, W. Li, P.H. Yang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	In the design of a multi-bend achromat (MBA) lattice for a diffraction-limited storage ring, there are usually many magnet parameters to be optimized and some stringent constraints to be satisfied. For example, to cancel out nonlinear dynamics effects, the phase advances between some sections are generally required to be set to certain values in the lattice design. For better designing a MBA lattice using an evolutionary algorithm, the handling of constraints will be important, because it is very hard to satisfy the constraints for most or even all of solutions in the early generations of the algorithm. This paper will first describe some methods for handling constraints, which are then applied to designing a hybrid 7BA lattice. The comparison of these methods shows that better lattice solutions can be obtained by including constraints into objective functions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW056
About •	paper received ※ 23 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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TUPGW057	A Ten-Bend Achromat Lattice with Interleaved Dispersion Bumps for a Diffraction-Limited Storage Ring	emittance, storage-ring, sextupole, quadrupole	1538
	P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Recently, a multi-bend achromat (MBA) lattice concept, called the MBA with interleaved dispersion bumps (IDB-MBA), was proposed to design the HALS storage ring, which presented better performance of both on- and off-momentum nonlinear dynamics. Since the beam emittance scales inversely with the third power of the number of bending magnets, in this paper we will study a new IDB-MBA lattice with more bending magnets. It is feasible to satisfy the requirement of the IDB-MBA concept in a 10BA lattice, and an IDB-10BA lattice is then designed for a storage ring light source with an energy of 2.4 GeV. The designed lattice has an ultra-low natural emittance of 81 pm·rad, and a dynamic aperture of about 6 mm and a large dynamic momentum aperture of 6% are achieved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW057
About •	paper received ※ 24 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW061	First Study for an Upgrade of the ALBA Lattice	emittance, injection, optics, dipole	1544
	G. Benedetti, U. Iriso, Z. Martí, F. Pérez ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	ALBA has started a study that will produce the design of a new lattice for a diffraction limited photon source. The baseline lattice should preserve the present circumference and energy, and keep the insertion device beamline source points as much as possible unchanged. The first solution is a 16-fold periodic ring based on a 7BA cell with dispersion bump, paired sextupoles and anti-bends. An emittance of 155 pm·rad would be reached without longitudinal gradient in the dipole magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW061
About •	paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPGW064	Trials of Beam-Based Sextupole Calibration through 2nd Order Dispersion	sextupole, storage-ring, optics, ECR	1551
	D.K. Olsson, Å. Andersson, M. Sjöström MAX IV Laboratory, Lund University, Lund, Sweden
	In order to achieve nominal performance in terms of the dynamic aperture and lifetime of a storage ring, it is important to be able to characterise and correct its second order optics. At the MAX IV 3 GeV storage ring in Lund, Sweden, the linearity of the 2nd order dispersion with chromatic sextupole field strengths has been utilised to investigate the sextupole circuits. The beating induced in the 2nd order dispersion when reducing the strength of a sextupole magnet can be compared to the beating in simulations. From this a beam-based sextupole calibration curve can be found. This work was inspired by similar work done at ESRF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW064
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW068	New Source for Bending Magnet Beam Lines at Ultra-Low-Emittance Ring	dipole, radiation, storage-ring, wiggler	1557
	M. Abbaslou, M. Sedaghatizadeh KNTU, Tehran, Iran S. Dastan, J. Rahighi, F. Saeidi ILSF, Tehran, Iran
	The Iranian Light Source Facility (ILSF) is a 3 GeV 3rd synchrotron radiation laboratory in the basic design phase. The Storage Ring (SR) is based on a five-bend achromat (5BA) lattice providing low horizontal emittance of 0.27 nm.rad. Due to the ILSF storage ring, straight section limits the use of the short length wigglers for hard X-ray generation is recommended. Which are removable in the lattice. In this article, the new design of the 3-pole wiggler is investigated and the main parameters of this 3-pole wiggler, by considering the ILSF storage ring characteristics, is modified. Also, the effect of the new 3-pole wiggler on the beam dynamics is investigated and the advantages of the new design are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW068
About •	paper received ※ 28 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW070	Multi-Bend Achromat Lattice Design for the Future of TPS Upgrade	emittance, dipole, storage-ring, dynamic-aperture	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	betatron, injection, storage-ring, dynamic-aperture	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	storage-ring, optics, emittance, dynamic-aperture	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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TUPGW078	Harmonic Cavity Design Choice for Lifetime Increase in Diamond-II	cavity, simulation, beam-loading, storage-ring	1585
	T. Olsson, R. Bartolini, I.P.S. Martin DLS, Oxfordshire, United Kingdom
	The ongoing trend towards synchrotron light storage rings with ultralow emittance leads to a requirement for strong magnet gradients, which reduce the dynamic aperture and thus the Touschek lifetime of the machine. This is also the case for the planned upgrade of the Diamond Light Source. One option to increase the Touschek lifetime is to lengthen the electron bunches with a harmonic cavity operated close to a harmonic of the fundamental RF frequency. This paper presents studies of a harmonic cavity for Diamond-II with the focus on maximising the lifetime increase. It is foreseen that the ring will have to operate with a gap in the fill pattern to avoid instabilities and therefore multiparticle tracking was used to determine the effect on stability and lifetime for various cavity parameters taking into account transient beam loading.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW078
About •	paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPGW079	Exploratory Lattice Design Studies for Diamond-II	controls, emittance, optics, dynamic-aperture	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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TUPGW080	Alternative Lattice Design for Diamond-II	emittance, sextupole, dipole, optics	1593
	M. Korostelev Oxford University, Physics Department, Oxford, Oxon, United Kingdom B. Singh DLS, Oxfordshire, United Kingdom
	Plans for upgrade of the Diamond Light Source aim to reduce beam emittance by a factor of 20 or better. This is motivated by demand for photon flux with significantly high brightness and transverse coherence. The baseline lattice design for the Diamond-II upgrade has been recently proposed, however alternative design are under investigation to reduce the emittance even further. This paper presents a new lattice design based on implementation of bending magnets with transverse field gradient only.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW080
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW090	Experimental Tests of the Automated APS-U Commissioning Algorithm at APS	MMI, sextupole, simulation, closed-orbit	1615

Paper

Title

Other Keywords

Page

MOPGW006

Long Range Beam Beam: Towards Faster Computations

optics, interaction-region, closed-orbit, betatron

72

S.R. Koscielniak
TRIUMF, Vancouver, Canada

We outline some features of a program of study toward faster computation of the cumulative effect of a sequence of beam-beam interactions across the interaction region.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW006

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paper received ※ 23 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW007

Electromagnetic Impulse of Beam Density F(x, y)G(z)

factory, site, storage-ring, interaction-region

75

S.R. Koscielniak
TRIUMF, Vancouver, Canada

We calculate the transverse impulse on a test particle as a bunch of charged particles beam passes by. It is often assumed, but seldom proven, that the EM field from a beam density distribution factored into transverse and longitudinal parts, F and G respectively, has also a factored form P(x, y)Q(z). This factorization is not possible for stationary charges. Contrastingly, it becomes increasingly accurate for ultra-relativistic particle beams. We give a general analysis, show how to develop the corrections in terms of integrals of F and derivatives of G. What is significant is that if we integrate over longitudinal coordinate z to find the transverse impulse on a witness charge, the correction terms integrate to zero leading to the impulse P(x, y)Integral[Q(z)] independent of bunch shape. If this result is already known, this paper serves as a reminder.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW007

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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MOPGW014

Developing Beam Optics for the BESSY VSR Project

optics, quadrupole, storage-ring, cavity

94

F. Andreas, M. Abo-Bakr, F. Armborst, P. Goslawski
HZB, Berlin, Germany

At BESSY II due to the continuously increasing interest in short pulse operation, a major upgrade of the ring will enable simultaneous storage of long and short bunches. This Variable pulse-length Storage Ring (VSR) will be achieved by the installation of additional superconducting high gradient cavities. The cavities will be assembled into one cryomodule in one of the straights of the storage ring. As this module needs more space then initially assumed, one possible solution is to remove two quadrupoles to gain available installation length. The quadrupoles were switched off in simulations and the lattice was optimized with regard to the linear order. The best solution found was transferred to the storage ring, where storage of high current with reasonable injection efficiency and lifetime was possible. The proposed optics has to be further optimized in terms of nonlinear beam dynamics, but has shown that an available installation length can be increased.

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW019

Beam-Beam Blowup Issue After Low Emittance Tuning for FCC-ee

emittance, simulation, optics, coupling

112

D. El Khechen, K. Oide, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW019

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW023

An Algorithm for Automated Lattice Design of Transfer Lines

quadrupole, focusing, dipole, target

127

S. Reimann, M. Droba, O. Meusel, H. Podlech
IAP, Frankfurt am Main, Germany

Since the last 20 years, modern heuristic algorithms and machine learning have been increasingly used for several purposes in accelerator technology and physics. Since computing power has become less and less of a limiting factor, these tools have become part of the physicist community’s standard toolkit. This paper describes the construction of an algorithm that can be used to generate an optimised lattice design for transfer lines under the consideration of restrictions that usually limit design options in reality. The developed algorithm has been applied to the existing SIS18 to HADES transfer line in GSI.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW023

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paper received ※ 28 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPGW029

Preliminary Study of Bunch Compression in the Hefei Light Source

storage-ring, radiation, electron, synchrotron-radiation

151

W. Li, Z.H. Bai, W. Li, J.G. Wang, D.R. Xu, Z. Zhao
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077), and the National Natural Science Foundation of China(GrantNo.11475167).
Short electron bunch has interesting applications in the synchrotron radiation light sources, such as the production of powerful coherent THz radiation, time resolving spectrum analysis, etc. In this work, we are interested in acquiring the short bunch in the storage ring with a small circumference like Hefei Light Source. In this paper, we tried to approach the short bunch in two separate methods: by increasing the higher harmonic cavity voltage and by reducing the momentum compaction factor. The preliminary result and observations are shown and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW029

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paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW040

Beam Optics Design of the Superconducting Region of the JAEA ADS

emittance, linac, cavity, controls

181

B. Yee-Rendón, Y. Kondo, F.M. Maekawa, S.I. Meigo, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

The Japan Atomic Energy Agency (JAEA) is proposing an Accelerator Driven Subcritical System (ADS) for the transmutation of the nuclear waste. ADS will consist of a superconducting CW proton linear accelerator of 30MW and a subcritical nuclear reactor core. The main part of the acceleration will take part in the superconducting region using five types of radio frequency cavities. The ADS operation demands a high intensity and reliability of the beam. Therefore, the beam optics design plays a fundamental role to reduce the beam loss, control emittance growth and beam halo.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW040

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paper received ※ 17 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW044

Off-Energy Off-Axis Injection with Pulsed Multipole Magnet Into the HALS Storage Ring

injection, storage-ring, kicker, multipole

187

G. Liu, Z.H. Bai, W. Li, L. Wang, P.N. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

As a future Diffraction-Limited Storage Ring (DLSR) at NSRL, the Hefei Advanced Light Source (HALS) has been proposed and has a great progress in the lattice optimization. The nonlinear dynamics is well designed and shows good performance, which makes it easier for beam injection and gives us more choices to design a more suitable injection scheme. In this paper, a new off-energy off-axis pulsed multipole injection scheme is proposed. The off-energy beam is off-axis injected into the acceptance of the storage ring with one or several pulsed multipole kickers and meanwhile the stored beam is almost unaffected during the injection. The injection acceptance of the storage ring is analyzed and the injection scheme is preliminary designed. A series of tracking simulations are carried out and the results are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW044

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paper received ※ 15 May 2019 paper accepted ※ 17 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, sextupole, dynamic-aperture

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW045

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paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPGW052

The Study of Single-Bunch Instabilities in the Ramping Process in the HEPS Booster

booster, impedance, simulation, injection

206

H.S. Xu, Y.M. Peng, N. Wang
IHEP, Beijing, People’s Republic of China

The booster of High Energy Photon Source (HEPS) is proposed to ramp the beam energy from 500 MeV to 6 GeV, and to deliver the required charge to the storage ring. However, the transverse single-bunch instability may limit the reachable bunch charge in the booster. The study of the transverse single-bunch instability has been carried out for the HEPS booster at both 500 MeV and 6 GeV to double check whether the required single-bunch charge can be achieved. Furthermore, the energy ramping process was recently included in the study. We concentrate in the analyses of the simulation results with the consideration of energy ramping process in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW052

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW062

Radiation of a Charge Moving in a Wire Structure

radiation, FEL, simulation, electron

231

S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev
Saint Petersburg State University, Saint Petersburg, Russia
A.I. Benediktovitch
EuXFEL, Hamburg, Germany
A.I. Benediktovitch
BSU, Minsk, Belarus, Belarus

Funding: This work is supported by the grant from Russian Foundation for Basic Research (No. 17-52-04107).
In the X-ray frequency region, interaction of relativistic electrons with crystals results in parametric X-ray radiation (PXR), with its frequency being determined by distance between crystallographic planes and direction of electron motion. If instead of crystal one considers an artificial periodic structure with periods of the order of mm, one can expect emission of radiation of a similar nature at terahertz (THz) frequencies. This frequency range is of significant interest during last decade due to its prospective applications. Moreover, artificial wire-like structures are considered as a promising alternative to conventional dielectric structures for wakefield acceleration*. Here we consider electromagnetic (EM) field produced by a charged particle bunch moving through a lattice of parallel conducting wires. We present several approaches for analysis of EM field in the described wire structure. First, conventional two-wave approximation for describing the "short-wave response" is developed. Second, we use the effective medium approach and describe the "long-wave" part of the spectrum. Third, we develop a method based on vibrator antenna theory which can be useful for finite length wire structure.
* P.D. Hoang, et al., Phys. Rev. Lett., V. 120, P. 164801 (2018).

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW063

Beam Dynamics Optimization in Drift Tube Linear Accelerator With Permanent Quadrupole Magnets

rfq, quadrupole, cavity, DTL

234

I. Skudnova
Saint Petersburg State University, Saint Petersburg, Russia

The research concerns the design of a drift tube linear accelerator (DTL) with permanent quadrupole magnets (PMQ) placed inside some of the drift tubes for focusing. The study was conducted using Comsol Multiphysics software, where electromagnetic fields and particle dy-namics in the cavity were calculated. The proton beam is accelerated up to 10 MeV. Initial beam is assumed to come from Radio Frequency Quadrupole accelerator (RFQ). Mathematical methods of control theory are used for particles dynamics optimization. Different focusing lattices are examined and variations of the gradient of the magnetic lenses are analyzed with respect to output beam parameters. Effectiveness of the optimization is estimated by the transmission rate and the emittance growth.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW063

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paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW090

Alignment of a Magnetic Lattice Based on Particle Tracking

alignment, optics, controls, sextupole

324

K.P. Nesteruk, C. Calzolaio, J.M. Schippers
PSI, Villigen PSI, Switzerland

In calculations based on particle tracking in 3D magnetic field maps alignment of the components of a magnetic lattice is essential to obtain desired properties of beam optics. In this contribution we propose a method to control and correct misalignments during the process of the beam optics design. These misalignments would result from overlapping fringe fields of different field maps. The 3D field maps are obtained from the software for electromagnetic calculations OPERA. The full 3D map is saved in the tracking coordinate system and a ROOT (An Object Oriented Data Analysis Framework) ntuple is then created for analysis. The trajectory of the reference particle is calculated by means of OPAL - open source code developed at the Paul Scherrer Institut (PSI). The transverse magnetic field profiles allow possible misalignments to be precisely determined and the corresponding corrections to be calculated. Moreover, the multipole content in discrete locations along the lattice can be controlled by performing a polynomial fit, which calculates the magnetic field harmonics with respect to the reference track. This method was used at PSI for a design of a model of the magnetic lattice for a superconducting gantry for proton therapy with a large momentum acceptance.
*An Object Oriented Data Analysis Framework - http://root.cern.ch

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW093

Optics Calibration for Routine Operations In Taiwan Photon Source

optics, quadrupole, operation, coupling

335

F.H. Tseng, C.H. Chen, P.J. Chou
NSRRC, Hsinchu, Taiwan

To ensure a stable performance of Taiwan Photon Source (TPS), we perform the calibration of accelerator optics using LOCO (Linear Optics from Closed Orbit) technique every month. After the optics and coupling corrections, the rms beta beatings in both planes are reduced to less than 1%. The emittance coupling ratio is also restored to within the design value.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW093

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paper received ※ 06 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPGW096

Beam Dynamics in MBA Lattices with Different Chromaticity Correction Schemes

sextupole, emittance, betatron, storage-ring

346

L. Hoummi, J. Resta-López, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L. Hoummi, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A. Loulergue, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

Ultra-low emittance lattices are being studied for the future upgrade of the 2.75 GeV SOLEIL storage ring. The candidate baseline lattice was inspired by the ESRF-EBS-type Multi-Bend-Achromat (MBA) lattice, introducing a (-I) transformation to compensate the nonlinear impact of sextupoles thanks to the lattice symmetry and tight control of the betatron phase advance between sextupoles. Whilst the final performance is still being optimized, other types of lattices are being considered for SOLEIL: This includes the so-called High-Order Achromat (HOA) lattice. Though the (-I) scheme provides a large on-momentum transverse dynamic aperture in 4D, its off-momentum performance is rather limited. 6D studies reveal intrinsic off-momentum transverse oscillations which are likely to result from a nonlinear increase in path length. This contribution presents the effects from the inhomogeneous sextupole distribution in the (-I) scheme and compares them with the HOA lattice.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW096

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW097

SOLEIL Storage Ring Upgrade Performance in Presence of Lattice Imperfections

quadrupole, sextupole, closed-orbit, dipole

350

A. Vivoli, A. Bence, P. Brunelle, A. Gamelin, L. Hoummi, A. Loulergue, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

The design for the upgrade of the SOLEIL third generation light source is progressing. At the present stage, different lattices are evaluated as possible candidates for the storage ring upgrade and an important factor for the comparison of their performances is the robustness against lattice imperfections. The strategy for this study consists in defining a set of misalignments of the lattice elements and field errors of the magnets that are expected to be attained after the commissioning, applying them to the lattice models and correcting them using response matrix based techniques. A dedicated algorithm was developed in Accelerator Toolbox in order to accomplish this procedure and compare the different lattices. In this paper the results of this study at the current state are presented, including the considered lattice imperfections, the correction method applied and the final performance of the lattices.

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paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPGW098

Iterative Trajectory-Correction Scheme for the Early Commissioning of Diffraction-Limited Light Sources

MMI, feedback, simulation, storage-ring

353

Ph. Amstutz, T. Hellert
LBNL, Berkeley, USA

The commissioning of diffraction-limited light sources will be significantly affected by the fact that typical lattice designs rely on very strong focussing elements in order to achieve the small emittance goals. Especially in the early-commissioning phase this can render procedures successfully used in the commissioning of existing third-generation light sources ill-suited for the application to these new machines. In this contribution we discuss an iterative approach to the early trajectory correction, based on the well-known pseudo-inversion of a trajectory-response matrix. Measuring this matrix during early commissioning can be cumbersome, so that an algorithm working with the model response matrix of the lattice is desirable. We discuss the stability of the iteration in the presence of lattice errors, resulting in differences between the actual and the model response matrix. Further, Tikhonov regularization is investigated as a means to trade off the RMS trajectory variation against the strength of the required corrector kicks.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW098

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW105

Preliminary Lattice Studies for the Single-Invariant Optics Experiment at the University of Maryland

experiment, octupole, optics, resonance

367

L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, I. Haber, D.B. Matthew
UMD, College Park, Maryland, USA
K.J. Ruisard
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is supported through DOE-HEP Award DESC0010301 and NSF Award PHY1414681.
A novel approach to transverse resonance suppression in next generation high-intensity accelerators is the use of nonlinear optical elements to induce large tune spreads which result in reduced responses to resonance driving perturbations*. In order to test this theory, we have built and characterized an octupole channel insert for use in the University of Maryland Electron Ring (UMER). This paper presents experimental lattice studies using a low space-charge intensity beam at an energy of 10keV with a beam current of ~150uA, tune depression < 0.005, and unnormalized RMS emittance of 4.3 mm-mr. We apply beam based measurement techniques in order to evaluate the quality of our single-invariant lattice and better understand the nonlinearities created by the octupole channel.
* V. Danilov and S. Nagaitsev, Nonlinear accelerator lattices with one and two analytic invariants, PRSTAB, 13, 084002, 2010.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW105

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paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW107

Study of Integrable and Quasi-Integrable Sextupole Lattice

sextupole, resonance, focusing, optics

371

L. Gupta, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
S. Baturin
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
S. Nagaitsev
Fermilab, Batavia, Illinois, USA

Funding: Funded through Center for Bright Beams, NSF award PHY-1549132
In order to maximize beam lifetime in circular particle accelerators, the nonlinear beam optics are optimized to maximize the dynamic aperture of the beam. The dynamic aperture (DA), which is a 6-D phase space volume of stable trajectories, depends on the strength of the nonlinearities in the machine, and is calculated via particle tracking. Current DA optimization processes include multi-objective genetic algorithm optimizers, and relies on minimizing the magnitudes of resonance driving terms (RDT), which are calculated from the nonlinear contribution to the one-turn-map. The process of searching through the parameter space for an ideal combination that maximizes DA is computationally strenuous. By setting up the sextupole channel such that it is resembles a symplectic integrator of a smooth Hamiltonian, with only a few sextupoles we are able to closely reproduce phase space trajectories of a smooth Hamiltonian up to the hyperbolic point. No chaos and resonances are observed if phase advance per one sextupole magnet in the channel does not exceed ~0.12x2 pi. Therefore, an important property of the suggested approach is the intrinsic elimination of the resonances, and minimization of corresponding RDTs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW107

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW110

Study of the Beam Current Effects on the NSLS-II Storage Ring Optics Using Turn-by-Turn Data

optics, storage-ring, dipole, operation

375

J. Choi, Y. Hidaka
BNL, Upton, Long Island, New York, USA

These days, the techniques using the turn-by-turn data are well developed in analyzing the accelerator optics. We compared the data for the low and high beam currents and studied the beam current effects on the storage ring lattice optics. Also, by comparing the local transfer matrices, we analyzed the amounts of the impacts on the linear optics around the ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW110

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW113

Experimental Demonstration of the Henon-Heiles Quasi-Integrable System at IOTA

octupole, experiment, optics, alignment

386

N. Kuklev, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
S. Nagaitsev, A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy.
The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report the first results of experimental investigation of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread and dynamic aperture preservation. Resilience to perturbations and imperfections in the lattice is explored. We conclude by outlining future research plans and discussing applicability to future high intensity accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW113

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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MOPGW114

Bayesian Approach for Linear Optics Correction

quadrupole, optics, GUI, distributed

390

Y. Li, W.X. Cheng, R.S. Rainer
BNL, Upton, Long Island, New York, USA

With a Bayesian approach, the linear optics correction algorithm for storage rings is revisited. In modern ring-based accelerators, optics corrections are determined from repetitive measurements which help identify systematic and random quadrupole errors in presence of various measurement noises. This process is a multivariate nonlinear regression problem driven by either a completed lattice model or a Jacobian matrix. Starting from the Bayes’ theorem, ’likelihood functions’ and ’prior probability’ distributions are extracted from a complete linear optics model. Under some assumptions, the least square algorithm and then the Jacobian matrix approach can be re-derived. The coherence of the correction algorithm is ensured through specifying a self-consistent regularization coefficient to prevent overfitting. Optimal weights for different correction objectives are obtained based on their measurement noise level. A new technique has been developed to resolve degenerated quadrupole errors when observed at a few select BPMs. A necessary condition of being distinguishable is that their optics response vectors seen at these specific BPMs should be near-orthogonal.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW114

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paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW115

A Cross-Cell Interleaved Nonlinear Lattice for Potential NSLS-II Upgrade

emittance, sextupole, optics, dynamic-aperture

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW115

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paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW124

Coherent Synchrotron Radiation Simulation for CBETA

simulation, linac, radiation, shielding

406

W. Lou, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes
SLAC, Menlo Park, California, USA
N. Tsoupas
BNL, Upton, Long Island, New York, USA

CBETA is an energy recovery linac accelerating from 6 MeV to 150 MeV in four linac passes, using a single return beamline accepting all energies from 42 to 150 MeV. While CBETA gives promise to deliver unprecedentedly high beam current with simultaneously small emittance, Coherent Synchrotron Radiation (CSR) can pose detrimental effect on the beam at high bunch charges and short bunch lengths. To investigate the CSR effects on CBETA, we used the established simulation code Bmad to track a bunch with different parameters. We found that CSR causes phase space dilution, and the effect becomes more significant as the bunch charge and recirculation pass increase. Potential ways to mitigate the effect involving vacuum chamber shielding and increasing bunch length are being investigated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW124

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW125

Lossless Crossing of 1/2 Resonance Stopband by Synchrotron Oscillations

resonance, experiment, betatron, storage-ring

410

G.M. Wang, Y. Li, J. Rose, T.V. Shaftan, V.V. Smaluk
BNL, Upton, Long Island, New York, USA

Funding: DOE under contract No.DE-AC02- 98CH10886
Modern high performance circular accelerators require sophisticated corrections of nonlinear lattices. The beam betatron tune footprint may cross many resonances, reducing dynamic aperture and causing particle loss. However, if particles cross a resonance reasonably fast, the beam deterioration may be minimized. In this paper, we present the experiments with the beam passing through a half-integer resonance stopband via chromatic tune modulation by exciting synchrotron oscillations. This is the first time that beam dynamics have been kept under precise control while the beam crosses a half-integer resonance. Our results convincingly demonstrate that particles can cross the half-integer resonance without being lost if the passage is reasonably fast and the resonance stopband is sufficiently narrow.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW125

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paper received ※ 13 May 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, dynamic-aperture, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP023

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paper received ※ 06 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP026

HE-LHC Optics Design Options

dipole, quadrupole, hadron, optics

492

J. Keintzel, M.P. Crouch, M. Hofer, T. Risselada, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
M. Hofer, J. Keintzel
TU Vienna, Wien, Austria
L. van Riesen-Haupt
University of Oxford, Oxford, United Kingdom
L. van Riesen-Haupt
JAI, Oxford, United Kingdom

The High Energy Large Hadron Collider (HE-LHC), a possible successor of the High Luminosity Large Hadron Collider (HL-LHC) aims at reaching a centre-of-mass energy of about 27 TeV using basically the same 16 T dipoles as for the hadron-hadron Future Circular Collider FCC-hh. Designing the HE-LHC results in a trade off between energy reach, beam stay clear as well as geometry offset with respect to the LHC. In order to best meet the requirements, various arc cell and dispersion suppressor options have been generated and analysed, before concluding on two baseline options, which are presented in this paper. Merits of each design are highlighted and possible solutions for beam stay clear minima are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP026

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paper received ※ 02 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB001

Low Emittance Tuning of FCC-ee

emittance, coupling, quadrupole, sextupole

574

T.K. Charles
The University of Melbourne, Melbourne, Victoria, Australia
S. Aumon, B.J. Holzer, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

The FCC-ee project studies the design of a future 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁶ cm^-2s^-1. In order to reach these luminosity requirements, extreme focusing is needed in the interaction regions. For the Z energy (45.6 GeV) lattice, the maximum beta value is 8322 m, and the vertical beta function is 0.8 mm at the IP. These aspects of the FCC-ee lattice make it particularly susceptible to misalignments and field errors, and therefore present an appreciable challenge for emittance tuning. A challenging correction scheme is proposed to reduce the coupling and the vertical emittance. We describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes special programs, that had been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. Thousands of misalignment and field error random seeds were introduced in MADX simulations and the final corrected lattices are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB001

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paper received ※ 09 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPRB003

Multi-Target Lattice for Muon Production From e⁺ Beam Annihilation on Target

target, positron, emittance, site

578

O.R. Blanco-García
LAL, Orsay, France
M. Antonelli, M.E. Biagini, M. Boscolo, A. Ciarma, S. Guiducci, C. Vaccarezza, A. Variola
INFN/LNF, Frascati, Italy
G. Cesarini
INFN-Roma, Roma, Italy
F. Collamati
INFN-Roma1, Rome, Italy
R. Li Voti
Sapienza University of Rome, Rome, Italy
P. Raimondi
ESRF, Grenoble, France

The Low Emittance Muon Accelerator~(LEMMA) aims at producing small emittance muons from positron annihilation with electrons in a target. Given the low cross section of the production process, a large number of positrons on the target are required, exposing it to high power deposition and the beam to large degradation because of multiple scattering and bremstrahlung. A multi-target IP, and multi-IP line has been studied to reduce the power deposition per target and the degradation of the positron beam while preserving the number of muon pairs produced. The lattice copes with the focusing and transport of three beams at two different energies, the positron beam at 45 GeV, and µ⁺+ and µ⁻ beams at 22.5~GeV. Studies on the beam dynamics, number of targets, material and thickness of the targets are reported in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB003

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB005

Study of Higher-Order Achromat Lattice as an Alternative Option for the SOLEIL Storage Ring Upgrade

sextupole, storage-ring, octupole, injection

586

R. Nagaoka, A. Bence, P. Brunelle, L. Hoummi, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux, A. Vivoli
SOLEIL, Gif-sur-Yvette, France
A. Gamelin
LAL, Orsay, France

A ring composed of 20 symmetrical 7BA cells in which of a pair of chromaticity correcting sextupoles placed around horizontal dispersion bumps à la ESRF-EBS was developed as a baseline lattice for the SOLEIL storage ring upgrade (presented at IPAC2018). The strict phase relation between the two dispersion bumps provides an efficient way of optimizing the (on-momentum) nonlinear optics with a limited number of sextupoles. As an alternative, a scheme known as Higher-Order Achromat (HOA) develops a MBA (Multi-Bend Achromat) lattice where chromaticity correcting sextupoles are distributed in each M unit cell with a strict phase relation cell-wise such as to cancel basic geometric and chromatic resonance driving terms. The beam dynamics in a 20-fold 7BA HOA ring is compared with those of the baseline lattice, with focus on off-momentum properties such as Touschek lifetime, which are important for medium energy rings like SOLEIL. The robustness against errors, the reduction of the ring symmetry by introducing 4 longer straight sections, as well as a horizontal dispersion bump to cope with longitudinal on-axis injection scheme are also presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB005

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paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB027

Progress of HEPS Accelerator System Design

storage-ring, cavity, booster, vacuum

633

P. He, J.S. Cao, F.S. Chen, J. Chen, H. Dong, D.Y. He, Y. Jiao, W. Kang, C.H. Li, J.Y. Li, F. Long, H.H. Lu, X. Qi, Q. Qin, H. Qu, J.Q. Wang, G. Xu, J.H. Yue, J. Zhang, J.R. Zhang, P. Zhang
IHEP, Beijing, People’s Republic of China

The 4th generation ring-based light sources, HEPS (High Energy Photon Source) 7BA lattice has been de-veloped at IHEP. This is 6Gev, 200mA machine which has horizontal emittance Ɛh around 60pm.rad to gain the high brilliance photon beam. this compact lattice design bring so many engineering challenges for accelerator magnets, vacuum components, beam diagnotice, etc. This paper will present the noval lattice design and subsystem design progress.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB027

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB062

nuSTORM Decay Ring

quadrupole, resonance, closed-orbit, emittance

716

J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
R.B. Appleby, S.C. Tygier
UMAN, Manchester, United Kingdom
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Precise neutrino cross section measurements and search for sterile neutrinos can be done with neutrino beams produced from muons decaying in a storage ring due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a racetrack storage ring, where circulating muon beam would be captured. The storage ring has three options: a FODO solution with large aperture quadrupoles, a racetrack FFA (Fixed Field Alternating gradient) using the recent developments in FFAs and a hybrid solution of the two previous options. Machine parameters, linear optics design and beam dynamics of the hybrid solution are discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB062

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB074

Using an Energy Scan to Determine the Tunes and Orbit in the First FFA Girder of CBETA

betatron, linac, cryomodule, MMI

742

C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg
BNL, Upton, Long Island, New York, USA

This work reports the results of performing a scan of the beam energy performed during the Fractional Arc Test of the CBETA machine, a multi-pass SRF ERL featuring a non-scaling FFA return loop. The FFA arc consists of identical doublets that are designed to have an energy acceptance from 42 to 150 MeV, with a betatron phase advance (i.e., tune) per cell and periodic orbit position that depends on energy. In the CBETA fractional arc test, we transport the beam through 4 such cells (the first girder), and are capable of injecting beam in to the arc with energies as high as 59 MeV. By creating betatron oscillations in the arc, we can compute the phase advance per cell and periodic orbit position as a function of energy within that range. In addition, because the phase advance varies as a function of energy, the computation also provides an estimate of the offsets of the BPMs in that arc.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB074

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB076

CBETA Beam Commissioning Results

linac, MMI, permanent-magnet, electron

748

C.M. Gulliford, N. Banerjee, A.C. Bartnik, I.V. Bazarov, J.A. Crittenden, K.E. Deitrick, A. Galdi, G.H. Hoffstaetter, P. Quigley, K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, R.J. Michnoff, D. Trbojevic
BNL, Upton, Long Island, New York, USA

We report on the first results of commissioning CBETAwith a fully closed return loop. We repeat much of our early commissioning from the fractional arc test, namely setting up the injection system, calibrating the main linac, and steering the beam through the first splitter line. Most importantly, first results from sending the beam all the way through the FixedField Alternating gradient permanent magnet return arc are described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB076

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB092

Symplectic and Exact Tracking of Low Energy 197Au⁷⁸⁺ in the Relativistic Heavy Ion Collider

electron, quadrupole, simulation, storage-ring

791

Y. Luo, W. Fischer, F. Méot, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the coming RHIC low energy scan, the electron cooling technique is to be used to cool the ions 197Au⁷⁹⁺ with its energy range between 3.85~GeV/nucleon to 5.75~GeV/nucleon. To overlap the electron beam and the 197Au⁷⁹⁺ beam at the cooling section, a recombination monitor is to be used to detect the maximum flux of 197Au⁷⁸⁺ ions generated in the cooling section. In the previous studies, we tracked 197Au⁷⁸⁺ ions through the RHIC lattice defined with 197Au⁷⁹⁺ with an equivalent momentum deviation. In the article, we explode different symplectic ways to track 197Au⁷⁸⁺ ions exactly. We calculate and compare the trajectories and loss map of 197Au⁷⁸⁺ ions through the RHIC ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB092

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS003

Superconducting LINAC Design Upgrade in View of the 100 MeV MYRRHA Phase I

linac, cavity, cryomodule, emittance

837

F. Bouly, M.A. Baylac
LPSC, Grenoble Cedex, France
A. Gatera
SCK•CEN, Mol, Belgium
D. Uriot
CEA-DRF-IRFU, France

Funding: Part of this work supported by the European Atomic Energy Community (EURATOM) H₂020 Programme under grant agreement n°662186 (MYRTE project).
The goal of the MYRRHA project is to demonstrate the technical feasibility of transmutation in a 100 MW Accelerator Driven System (ADS) by building a new flexible irradiation complex at Mol (Belgium). The MYRRHA facility requires a 600 MeV accelerator delivering a maximum proton current of 4 mA in continuous wave operation, with an additional requirement for exceptional reliability. Supported by SCK•CEN and the Belgium government the project has entered in its phase I: which consists in the development and the construction of the linac first part, up to 100 MeV. We review the design updates of the superconducting linac, with its enhanced fault-tolerance capabilities. The linac capabilities at 100 MeV (Phase I) and 600 MeV (ADS operation) are exposed and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS003

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paper received ※ 23 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS004

2nd Order Optics Symmetrisation through Off-Energy Orbit Response Matrix Analysis

sextupole, optics, storage-ring, alignment

841

D.K. Olsson, Å. Andersson, M. Sjöström
MAX IV Laboratory, Lund University, Lund, Sweden

The MAX IV 3 GeV storage ring lattice contains several strong sextupoles. In order to achieve nominal lattice performance it is important to be able to characterise and correct the higher order magnets and optics of the lattice. This has been done through the analysis of the Off-Energy Response Matrix (OEORM). Its approximate linearity in sextupole strength has been utilised to identify sextupole errors, as well as symmetrise the 2nd order optics. The symmetrisation was able to correct chromaticity, and increase horizontal acceptance by 50 %, compared to magnet settings based solely on rotating coil measurements. An approximate decrease of 10 % in vertical acceptance was detected. This work was inspired by similar investigations at ESRF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS004

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS010

Simulation of the Guide Field Flipping Procedure for the Frequency Domain Method

GUI, simulation, sextupole, dipole

858

A.E. Aksentyev
FZJ, Jülich, Germany
A.E. Aksentyev
MEPhI, Moscow, Russia
A.E. Aksentyev, V. Senichev
RAS/INR, Moscow, Russia

The spin vector of a particle injected into a perfectly aligned storage ring precesses about the vertically-orientated guide field. In the presence of an Electric Dipole Moment (EDM), the spin precession axis acquires a proportional radial component. However, in an imperfect ring, rotational magnet misalignments induce a radial component to the spin precession axis, related to the Magnetic Dipole Moment (MDM). In the Frequency Domain Method, [*] this additional precession is dealt with by consecutively injecting the beam in opposite directions, and constructing the EDM estimator as the sum of the clockwise and counter-clockwise vertical plane precession frequencies. Since the radial MDM component changes sign when the magnetic field direction is reversed, it cancels in the sum, leaving only the EDM effect. In order to reproduce the guide field magnitude with precision sufficient for the cancellation of the MDM effect, we propose to calibrate the guide field via the horizontal plane precession frequency. In the present work we describe the algorithm of the field flipping procedure, and do a numerical simulation.
[*] Senichev Y, Aksentev A, Ivanov A, Valetov E. Frequency domain method of the search for the deuteron electric dipole moment in a storage ring with imperfections. arXiv:171106512. 2017 Nov 17.

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paper received ※ 08 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPTS011

Spin Motion Perturbation Effect on the EDM Statistic in the Frequency Domain Method

betatron, polarization, dipole, storage-ring

861

A.E. Aksentyev
FZJ, Jülich, Germany
A.E. Aksentyev
MEPhI, Moscow, Russia
A.E. Aksentyev, V. Senichev
RAS/INR, Moscow, Russia

The spin precession axis of a particle involved in betatron motion precesses about the invariant spin axis defined on the closed orbit (CO). This precession can be observed in polarization data as a rapid, small-amplitude oscillation on top of the major effect oscillation caused by the precession of spin about the CO axis. The frequency of this latter oscillation is used in the Frequency Domain (FD) methodology as the EDM observable. [*] It is estimated by fitting polarimetry data by a sine function; the rapid oscillations, therefore, constitute a model specification error. This model error might introduce a bias into the frequency estimate. In the present work we investigate the effect of the spin precession axis motion on measurement data and fit quality, and conclude that it is not only insignificant (with regard to data perturbation) compared to spin tune variation, but is also controllable via the application of a Spin Wheel.
[*] Senichev Y, Aksentev A, Ivanov A, Valetov E. Frequency domain method of the search for the deuteron electric dipole moment in a storage ring with imperfections. arXiv:171106512. 2017 Nov 17

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MOPTS012

Spin Decoherence in the Frozen Spin Storage Ring Method of Search for a Particle EDM

sextupole, storage-ring, simulation, betatron

864

A.E. Aksentyev
FZJ, Jülich, Germany
A.E. Aksentyev
MEPhI, Moscow, Russia
A.E. Aksentyev, V. Senichev
RAS/INR, Moscow, Russia

Spin coherence refers to a measure of preservation of polarization in an initially polarized beam. The spin vector of a particle injected into a storage ring starts to precess about the vertical magnetic field vector in accordance with the Thomas-BMT equation. The precession frequency is dependent on the equilibrium-level energy, which differs across the beam particles. This does not pose a problem when the initial polarization is vertical; however, the Frozen Spin Storage Ring EDM search method [*] requires beam polarization along the momentum vector, i.e., in the horizontal plane. In the present work we analyze the source of decoherence, and investigate the way it can be suppressed in the horizontal plane in a perfectly aligned ring by means of sextupole fields. We also consider the case of an imperfect ring: transference of decoherence into the vertical plane induced by vertical plane spin precession, and the effect of sextupole fields.
* D. Anastassopoulos et al. AGS Proposal: Search for a permanent electric dipole moment of the deuteron nucleus at the 10 −29 e · cm level. BNL report, 2008.

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MOPTS038

BEAM DYNAMICS OF HIGH CHROMATICITY LATTICE FOR IRANIAN LIGHT SOURCE FACILITY (ILSF) STORAGE RING

storage-ring, dynamic-aperture, 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

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paper received ※ 29 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS040

Beta Beating and Coupling Correction of the ILSF Storage Ring

coupling, quadrupole, closed-orbit, alignment

946

A.M. Mash’al, E. Ahmadi, S. Dastan, J. Rahighi
ILSF, Tehran, Iran
F.D. Dabbagh Kashani
IUST, Narmac, Tehran, Iran

The Iranian Light Source Facility (ILSF) is a 3 GeV synchrotron radiation facility, which is in the design stage. Inevitable errors like imperfection of magnetic field and misalignment of magnets will introduce various destructive effects on the performance of the machine. The possibility of correcting the errors should be thoroughly examined before settling the design. In this paper, the correction process of beta beating and coupling with LOCO is described. The rms beta beating in horizontal and vertical planes after correction are reduced to 1% and 2% respectively. The average coupling ratio of lattice for 100 random error distribution is corrected to 0.2%.

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUXXPLS3

The Design Optimization of the Dielectric Assist Accelerating Structure for Better Heat and Gas Transfer

cavity, vacuum, multipactoring, embedded

1179

S. Mori, M. Yoshida
KEK, Ibaraki, Japan
D. Sato
AIST, Tsukuba, Ibaraki, Japan

The dielectric-assist accelerating (DAA) structure is a dielectric-inserted normal-conducting cavity, which provides high Q value at room temperature. This accelerating structure is composed of dielectric disks and a dielectric cylindrical layer inserted in a copper cavity. For the realistic operation, the removal of heat from the dielectric cells and the vacuum evacuation of gas inside the cylindrical layers have not considered yet. In order to solve the problems, we propose the optimized design of the DAA structure, where the extended part of the dielectric disk is embedded in the copper cavity and the choke structure is applied. We show the result of the electromagnetic-field simulation of the extended DAA structure and the thermal simulation to clarify the relation between a duty factor and maximum temperature of the dielectric cells.

Slides TUXXPLS3 [5.892 MB]

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUZPLS2

Beam Dynamics Study in the HEPS Storage Ring

storage-ring, emittance, photon, brightness

1203

Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is the first high-energy diffraction-limited storage ring (DLSR) light source to be built in China, with a natural emittance of a few tens of pm rad and a circumference of 1360.4 m. After 10 years’ evolution, the accelerator physics design of the HEPS has been basically determined, with the ring consisting of 48 hybrid-7BAs with anti-bends and super-bends. This paper will discuss the accelerator physics studies of the HEPS storage ring, covering issues of lattice design, nonlinear optimization, collective effects, error correction, insertion devices, etc.

Slides TUZPLS2 [9.517 MB]

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW004

Cls 2.2: Ultra-Brilliant Round Beams Using Pseudo Longitudinal Gradient Bends

quadrupole, injection, emittance, coupling

1385

L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada

A preliminary design for a new storage for the Canadian Light Source was presented at IPAC’18 (Dallin). More recently a reconfigured lattice was presented at the 6th DLSR workshop. This lattice employed large βy and small βx in the straights. This has several advantages including: increased transverse coherence and brighter beams at small coupling; round beams at small coupling; flatter βy through the straights; and possible off-axis vertical injection at small amplitudes. Most recently longitudinal gradients in the dipoles have been implemented. This has lead to the unit cell bends being replaced by a ’pseudo longitudinal gradient’ bend array: bend1-bend2-bend1. This results in smaller emittance with simple magnet designs while maintaining adequate dynamic aperture for off-axis injection.

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW011

Status of the PETRA IV project

emittance, brightness, timing, synchrotron

1404

I.V. Agapov, R. Bacher, M. Bieler, R. Bospflug, R. Brinkmann, Y.-C. Chae, H.C. Chao, H.T. Duhme, M. Ebert, H.-J. Eckoldt, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, U. Hurdelbrink, J. Keil, J. Klute, M. Körfer, B. Krause, G. Kube, W. Leemans, L. Lilje, F. Obier, A. Petrov, N. Plambeck, J. Prenting, G.K. Sahoo, H. Schlarb, M. Schlösser, F. Schmidt-Föhre, M. Schmitz, C.G. Schroer, T. Tempel, M. Thede, M. Tischer, R. Wanzenberg, E.F. Weckert, T. Wilksen, K. Wittenburg, J.X. Zhang
DESY, Hamburg, Germany

Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring.

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW016

New Operation Regimes at the Storage Ring KARA at KIT

optics, operation, injection, simulation

1422

A.I. Papash, E. Blomley, T. Boltz, M. Brosi, E. Bründermann, S. Casalbuoni, J. Gethmann, E. Huttel, B. Kehrer, A. Mochihashi, A.-S. Müller, R. Ruprecht, M. Schuh, J.L. Steinmann
KIT, Karlsruhe, Germany

The storage ring Karlsruhe Research Accelerator (KARA) at KIT operates in a wide energy range from 0.5 to 2.5 GeV. Initially, the ring was designed to serve as a Light Source for synchrotron radiation facility ANKA. Since then different operation modes have been implemented at KARA: in particular, the double bend achromat (DBA) lattice with non-dispersive straight sections, the theoretical minimum emittance (TME) lattice with distributed dispersion, and different versions of low compaction factor optics with highly stretched dispersion function. Short bunches of a few ps pulse width are available at KARA. Low alpha optics have been tested and implemented in a wide operational range of the ring and are now routinely used at 1.3 GeV for studies of CSR-induced beam dynamics and THz bursting in the micro-bunching instability. Different non-linear effects, in particular, residual high order components of magnetic fields generated in insertion devices have been studied and cured. A new operation mode at high vertical tune implemented at KARA essentially improves beam performance during user operation as well as at low alpha regimes.

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paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW018

PETRA IV Study with Non-Interleaved Sextupole Scheme

sextupole, emittance, storage-ring, optics

1430

H.C. Chao, R. Brinkmann, X.N. Gavaldà
DESY, Hamburg, Germany

This study is an attempt to design PETRA IV storage ring, which is an upgrade from PETRA III toward diffraction-limit synchrotron light source, based on the non-interleaved sextupole scheme. The lattice is constructed by mixing different types of cells. There are two basic building blocks. The double minus identity (DMI) cell dedicated for the chromaticity correction with non-interleaved sextupoles is tightly built up, while the combined function FODO cell with dispersion suppressors provides straights with small beta functions ideally for undulators. In addition, the hybrid section including a 10-m long super insertion device (ID) is custom-made to adapt to DESY’s current site plan. The beam dynamic behaviors are simulated and discussed.

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paper received ※ 18 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW020

Non-Linear Features of the cSTART Project

storage-ring, quadrupole, sextupole, injection

1437

B. Härer, E. Bründermann, A.B. Kaiser, A.-S. Müller, A.I. Papash, R. Ruprecht, J.M. Schaefer, M. Schuh
KIT, Karlsruhe, Germany

The compact storage ring for accelerator research and technology (cSTART) is being designed and will be realized at the Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT). One important goal of the project is to demonstrate injection and storage of a laser wakefield accelerator (LWFA) beam in a storage ring. As a first stage the compact linear accelerator FLUTE will serve as an injector of 50 MeV bunches to test the ring’s performance. A highly non-linear lattice of DBA-FDF type was studied extensively. The specific features of ring optics are reported. A special transfer line from FLUTE to cSTART including bunch compressor and non-linear elements is presented that maintains the ultra-short bunch length of FLUTE.

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TUPGW021

An Accelerator Toolbox (AT) Utility for Simulating the Commissioning of Storage-Rings

MMI, simulation, injection, alignment

1441

T. Hellert, Ph. Amstutz, C. Steier, M. Venturini
LBNL, Berkeley, California, USA

We present the development of an AT-based toolkit, which allows for realistic commissioning simulations of storage ring light sources by taking into account a multitude of error sources as well as diligently treating beam diagnostic limitations.

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TUPGW022

Commissioning Simulation Study for the Accumulator Ring of the Advanced Light Source Upgrade

MMI, injection, quadrupole, simulation

1445

T. Hellert, Ph. Amstutz, M.P. Ehrlichman, S.C. Leemann, C. Steier, C. Sun, M. Venturini
LBNL, Berkeley, California, USA

The Advanced Light Source Upgrade (ALS-U) to a diffraction-limited soft x-rays light source requires the construction of an Accumulator Ring (AR) to enable swap-out, on-axis injection. The AR lattice is a Triple-Bend-Achromat lattice similar to that of the current ALS but to minimize the magnet sizes the vacuum chamber will be significantly narrower hence requiring a careful evaluation of the magnets’ field quality. This work presents the results of a detailed error tolerance study including a complete simulation of the commissioning process.

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW039

Error Study and Correction of Hefei Advanced Light Source

optics, quadrupole, closed-orbit, coupling

1492

D.R. Xu, Z.H. Bai, W. Li
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Hefei Advanced Light Source (HALS) is a future diffraction limited storage ring. The machine performance under all kinds of magnet errors is a vital component in physical design. In this paper, we present our work on the closed orbit correction, the linear beam optics compensation and the coupling control in HALS. After correction, the dynamical aperture can suffice the injection scheme.

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TUPGW040

Study of Seven-Bend Achromat Lattices with Interleaved Dispersion Bumps for HALS

storage-ring, emittance, octupole, linear-dynamics

1495

Z.H. Bai, W. Li, G. Liu, L. Wang, D.R. Xu, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Previously, we proposed a multi-bend achromat (MBA) lattice concept, called the MBA with interleav-ed dispersion bumps, which was then used to design a 7BA lattice for the Hefei Advanced Light Source (HALS) storage ring. Recently, such a 7BA lattice was further designed and optimized for the HALS by changing the number of lattice cells, scanning working point and employing octupoles. And two new HALS designs with such 7BA lattices have been made, one with 30 lattice cells and a natural emittance of 25 pm·rad and the other with 28 cells and 33 pm·rad. They had much better nonlinear dynamics perfor-mances than the previous design. The detailed study for these two HALS lattices will be presented in this paper.

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TUPGW041

Super-Period Locally Symmetric Lattices for Designing Diffraction-Limited Storage Rings

storage-ring, emittance, sextupole, quadrupole

1498

Z.H. Bai, W. Li, G. Liu, L. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China
Y. Li
BNL, Upton, Long Island, New York, USA

To achieve better nonlinear dynamics performance for a diffraction-limited storage ring, previously we proposed a locally symmetric multi-bend-achromat (MBA) lattice concept, where beta functions are locally symmetric about two mirror planes of each lattice cell. To have both high-beta long straight sections for beam injection and low-beta ones for higher brightness of insertion device radiation, many storage ring light sources use super-period lattices. The locally symmetric MBA lattice can be naturally extended to the super-period case. In the super-period locally symmetric (SP-LS) lattice, many nonlinear dynamics effects can be effectively cancelled out within one super-period lattice cell, and also there are many knobs to be used for further nonlinear optimization. As examples, two SP-LS lattices have been designed towards diffraction-limited emittances.

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paper received ※ 20 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW042

Study of the Intra-beam Scattering Effects in the HALS Storage Ring

emittance, damping, wiggler, storage-ring

1501

W. Li, Z.H. Bai, W. Li, D.R. Xu, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077).
The Hefei Advanced Light Source (HALS) is designed to be a dedicated 4th generation diffraction limited light source. In 2018, the baseline lattice of the HALS storage ring has been proposed, with an ultra-low natural emittance of about 25 pm-rad. The preliminary study of intra-beam scattering effects on the beam emittance growth in the HALS storage ring has been performed with this baseline lattice. Due to the limited synchrotron radiation in this storage ring, damping wigglers are expected in this storage ring to reduce the damping time and reduce the emittance. In this paper, we will present the simulation results of the IBS effects, estimated effectiveness of damping wiggler and the corresponding linear optics calibration of the perturbation due to insertion device, and finally the estimated Touschek lifetime will be shown.

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TUPGW046

Progress of Lattice Design and Physics Studies on the High Energy Photon Source

storage-ring, booster, photon, injection

1510

Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is an ul-tralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physics design and related studies of HEPS over the past year, covering issues in storage ring lattice design, injection and injector design, insertion device effects, error study and lattice calibration, collective effects, etc.

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TUPGW052

STUDY OF THE RAMPING PROCESS FOR HEPS BOOSTER

booster, storage-ring, damping, injection

1521

Y.M. Peng, J.Y. Li, C. Meng, H.S. Xu
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is a 6-GeV, ul-tralow-emittance storage ring light source to be built in Huairou District, Beijing, China. The beam energy ramps from 500 MeV to 6 GeV in 400 ms, during which the RF voltage increases accordingly to keep the momentum acceptance large enough. The booster is designed to operate at 1 Hz repetition frequency. In this paper the energy ramping curve, RF choice, beam parameters changing curves and eddy current effect in HEPS booster will be presented.

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TUPGW053

Simulations of the Injection Transient Instabilities for the High Energy Photon Source

injection, feedback, simulation, storage-ring

1524

Z. Duan, N. Wang, H.S. Xu
IHEP, Beijing, People’s Republic of China

Funding: Work supported by Natural Science Foundation of China (No.11605212).
A "charge recovery in booster" scheme* was proposed to deliver the full charge bunches for the swap-out injection of the High Energy Photon Source. In this scheme, the booster is employed also as a full energy accumulator ring to capture the high charge bunch extracted from the storage ring via merging with the small charge bunch accelerated in the booster, after enough damping in the booster for about 20 ms, the recovered full charge bunch is re-injected into the storage ring. This scheme avoids the challenges to accelerate a bunch charge of ~ 15 nC, and is cost effective compared to building a dedicated 6 GeV accumulator ring. However, there will be a period of time during injection that one bunch is missing in the storage ring, which inevitably introduces some injection transients. Since "transparency" to the user experiments is a desired feature of injection schemes for next generation diffraction-limited storage rings, the injection transient effects are simulated for the proposed injection scheme, and how it would affect the user experiments are carefully evaluated.
* Z. Duan, et al., "The swap-out injection scheme for the High Energy Photon Source", Proc. IPAC’18, THPMF052

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TUPGW054

Design of a Hybrid Seven-Bend-Achromat Lattice for a High-Energy Diffraction-Limited Storage Ring Using a New Optimization Method

linear-dynamics, emittance, optics, sextupole

1528

P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Recently, we proposed a new optimization method, with nonlinear dynamics indicators considered in the linear optics design, for designing hybrid multi-bend-achromat (MBA) lattices. With this method, two hybrid MBA lattices for medium-low-energy diffraction limited storage rings (DLSRs) have been designed, showing remarkable effectiveness in improving nonlinear dynamic performance. In this paper, we will apply this optimization method to the design of a hybrid 7BA lattice for a 6 GeV DLSR with the same circumference as that of HEPS. In the design, the strengths and arrangement of magnets of this lattice also meet the engineering requirement for HEPS. The designed lattice has a natural emittance of 34 pm·rad. The nonlinear dynamic performance is satisfactory, with a dynamic aperture of about 6 mm and 3 mm in the horizontal and vertical directions, respectively, and a dynamic momentum aperture of larger than 5%, which also shows the power of our optimization method.

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TUPGW055

Comparison of Optimization Methods for Hybrid Seven-Bend-Achromat Lattice Design

linear-dynamics, sextupole, optics, emittance

1532

P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Generally, for a hybrid multi-bend-achromat (MBA) lattice with fixed linear optics, there is little potential to further optimize the nonlinear dynamics due to limited free knobs. To obtain a hybrid MBA lattice with better nonlinear dynamics performance, it is better to consider some indicators of nonlinear dynamics as objective functions in designing the linear optics using an optimization algorithm. In this paper, integral strengths of sextupoles and natural chromaticities are used as the nonlinear dynamics indicators, and different optimization methods with both or either of the two indicators are carried out and compared. As an example, a hybrid 7BA lattice with an energy of 2.4 GeV is designed towards an emittance of less than 70 pm·rad.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW055

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paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW056

Comparison of Constrained Optimization Methods for Designing a Multi-Bend Achromat Lattice

emittance, sextupole, storage-ring, linear-dynamics

1535

J.H. Xu, Z.H. Bai, W. Li, P.H. Yang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In the design of a multi-bend achromat (MBA) lattice for a diffraction-limited storage ring, there are usually many magnet parameters to be optimized and some stringent constraints to be satisfied. For example, to cancel out nonlinear dynamics effects, the phase advances between some sections are generally required to be set to certain values in the lattice design. For better designing a MBA lattice using an evolutionary algorithm, the handling of constraints will be important, because it is very hard to satisfy the constraints for most or even all of solutions in the early generations of the algorithm. This paper will first describe some methods for handling constraints, which are then applied to designing a hybrid 7BA lattice. The comparison of these methods shows that better lattice solutions can be obtained by including constraints into objective functions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW056

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paper received ※ 23 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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TUPGW057

A Ten-Bend Achromat Lattice with Interleaved Dispersion Bumps for a Diffraction-Limited Storage Ring

emittance, storage-ring, sextupole, quadrupole

1538

P.H. Yang, Z.H. Bai, J.J. Tan, L. Wang, J.H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Recently, a multi-bend achromat (MBA) lattice concept, called the MBA with interleaved dispersion bumps (IDB-MBA), was proposed to design the HALS storage ring, which presented better performance of both on- and off-momentum nonlinear dynamics. Since the beam emittance scales inversely with the third power of the number of bending magnets, in this paper we will study a new IDB-MBA lattice with more bending magnets. It is feasible to satisfy the requirement of the IDB-MBA concept in a 10BA lattice, and an IDB-10BA lattice is then designed for a storage ring light source with an energy of 2.4 GeV. The designed lattice has an ultra-low natural emittance of 81 pm·rad, and a dynamic aperture of about 6 mm and a large dynamic momentum aperture of 6% are achieved.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW057

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paper received ※ 24 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW061

First Study for an Upgrade of the ALBA Lattice

emittance, injection, optics, dipole

1544

G. Benedetti, U. Iriso, Z. Martí, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

ALBA has started a study that will produce the design of a new lattice for a diffraction limited photon source. The baseline lattice should preserve the present circumference and energy, and keep the insertion device beamline source points as much as possible unchanged. The first solution is a 16-fold periodic ring based on a 7BA cell with dispersion bump, paired sextupoles and anti-bends. An emittance of 155 pm·rad would be reached without longitudinal gradient in the dipole magnets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW061

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPGW064

Trials of Beam-Based Sextupole Calibration through 2nd Order Dispersion

sextupole, storage-ring, optics, ECR

1551

D.K. Olsson, Å. Andersson, M. Sjöström
MAX IV Laboratory, Lund University, Lund, Sweden

In order to achieve nominal performance in terms of the dynamic aperture and lifetime of a storage ring, it is important to be able to characterise and correct its second order optics. At the MAX IV 3 GeV storage ring in Lund, Sweden, the linearity of the 2nd order dispersion with chromatic sextupole field strengths has been utilised to investigate the sextupole circuits. The beating induced in the 2nd order dispersion when reducing the strength of a sextupole magnet can be compared to the beating in simulations. From this a beam-based sextupole calibration curve can be found. This work was inspired by similar work done at ESRF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW064

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW068

New Source for Bending Magnet Beam Lines at Ultra-Low-Emittance Ring

dipole, radiation, storage-ring, wiggler

1557

M. Abbaslou, M. Sedaghatizadeh
KNTU, Tehran, Iran
S. Dastan, J. Rahighi, F. Saeidi
ILSF, Tehran, Iran

The Iranian Light Source Facility (ILSF) is a 3 GeV 3rd synchrotron radiation laboratory in the basic design phase. The Storage Ring (SR) is based on a five-bend achromat (5BA) lattice providing low horizontal emittance of 0.27 nm.rad. Due to the ILSF storage ring, straight section limits the use of the short length wigglers for hard X-ray generation is recommended. Which are removable in the lattice. In this article, the new design of the 3-pole wiggler is investigated and the main parameters of this 3-pole wiggler, by considering the ILSF storage ring characteristics, is modified. Also, the effect of the new 3-pole wiggler on the beam dynamics is investigated and the advantages of the new design are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW068

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paper received ※ 28 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW070

Multi-Bend Achromat Lattice Design for the Future of TPS Upgrade

emittance, dipole, storage-ring, dynamic-aperture

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW070

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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

betatron, injection, storage-ring, dynamic-aperture

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW071

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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

storage-ring, optics, emittance, dynamic-aperture

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW075

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paper received ※ 20 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW078

Harmonic Cavity Design Choice for Lifetime Increase in Diamond-II

cavity, simulation, beam-loading, storage-ring

1585

T. Olsson, R. Bartolini, I.P.S. Martin
DLS, Oxfordshire, United Kingdom

The ongoing trend towards synchrotron light storage rings with ultralow emittance leads to a requirement for strong magnet gradients, which reduce the dynamic aperture and thus the Touschek lifetime of the machine. This is also the case for the planned upgrade of the Diamond Light Source. One option to increase the Touschek lifetime is to lengthen the electron bunches with a harmonic cavity operated close to a harmonic of the fundamental RF frequency. This paper presents studies of a harmonic cavity for Diamond-II with the focus on maximising the lifetime increase. It is foreseen that the ring will have to operate with a gap in the fill pattern to avoid instabilities and therefore multiparticle tracking was used to determine the effect on stability and lifetime for various cavity parameters taking into account transient beam loading.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW078

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paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPGW079

Exploratory Lattice Design Studies for Diamond-II

controls, emittance, optics, dynamic-aperture

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW079

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW080

Alternative Lattice Design for Diamond-II

emittance, sextupole, dipole, optics

1593

M. Korostelev
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
B. Singh
DLS, Oxfordshire, United Kingdom

Plans for upgrade of the Diamond Light Source aim to reduce beam emittance by a factor of 20 or better. This is motivated by demand for photon flux with significantly high brightness and transverse coherence. The baseline lattice design for the Diamond-II upgrade has been recently proposed, however alternative design are under investigation to reduce the emittance even further. This paper presents a new lattice design based on implementation of bending magnets with transverse field gradient only.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW080

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW090

Experimental Tests of the Automated APS-U Commissioning Algorithm at APS

MMI, sextupole, simulation, closed-orbit

1615

V. Sajaev
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357
APS Upgrade (APS-U) will feature hybrid seven-bend achromat lattice with very strong focusing elements and relatively small vacuum chamber aperture. Achieving design lattice parameters during commissioning will need to be accomplished quickly in order to minimize dark time for APS users. The paper will describe the automated start-to-end lattice commissioning algorithm starting with the first-turn trajectory correction and ending with the lattice correction. It will then show simulation results of the APS-U commissioning, and finally present results of the experimental tests of the commissioning at the existing APS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW090

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW091

Lattice Measurements of the APS Injector Rings

quadrupole, emittance, booster, dipole

1619

V. Sajaev, C. Yao
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357
APS Upgrade will feature an entirely new storage ring but will keep the existing injector complex consisting of the linear accelerator, Particle Accumulator Ring (PAR) and Booster. Due to small dynamic aperture of the APS Upgrade lattice, swap-out injection is adapted when an entire old bunch is replaced with a new bunch. This injection requires Booster to provide high-charge bunches with up to 17 nC in a single bunch. An extensive work is being carried out on characterizing the existing injector rings to ensure future high-charge operation. In this paper, we will present results of the lattice measurement using the response matrix fit. We will show the analysis of the achievable lattice measurement accuracy in the APS Booster and describe fit parameter modifications required to achieve good fit accuracy for the PAR.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW091

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW093

Compensation of Insertion Device Induced Emittance Variations in Ultralow Emittance Storage Rings by a Dispersion Bump in a Wiggler

emittance, wiggler, storage-ring, dipole

1627

F. Sannibale, M.P. Ehrlichman, T. Hellert, S.C. Leemann, D. Robin, C. Steier, C. Sun, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
Multi-bend achromat lattices allow for the design of extremely low emittance electron storage rings and hence for the realization of extremely high- brightness X-ray photon sources. In these new rings, the beam energy lost to radiation in the insertion devices (IDs) is often comparable to that lost in the ring dipole magnets. This implies that with respect to the typical 3rd generation light source, these new machines are more sensitive to the energy loss variations randomly occurring as the many users independently operate the gap of their IDs. The consequent induced variations in radiation damping time, equilibrium emittance, and transverse beam sizes at the radiation point sources can be significant and degrade the experimental performance in some of the beam-lines. In this paper we describe and discuss a possible method to compensate for such emittance variations by using a variable dispersion bump localized inside a fixed gap wiggler.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW093

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW095

Progress on a Novel 7BA Lattice for a 196-m Circumference Diffraction-Limited Soft X-Ray Storage Ring

emittance, sextupole, optics, storage-ring

1635

S.C. Leemann, F. Sannibale
LBNL, Berkeley, USA
M. Aiba, A. Streun
PSI, Villigen PSI, Switzerland
J. Bengtsson
DLS, Oxfordshire, United Kingdom
L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The ALS Upgrade to a diffraction-limited soft x-ray storage ring calls for ultralow emittance in a very limited circumference. In this paper we report on progress with a lattice based on a 7BA with distributed chromatic correction. This lattice relies heavily on longitudinal gradient bends and reverse bending in order to suppress the emittance, so that, despite having only seven bends, ultralow emittance can be achieved in addition to large dynamic aperture and momentum acceptance. An initial alternate 7BA lattice has been revised to relax magnet requirements as well as further increase off-energy performance and resilience to machine imperfections. We now demonstrate ±2.5 mm dynamic aperture including errors and calculate the effect of IBS to show that this lattice achieves 6 hours Touschek lifetime (at 500 mA, including errors) and a brightness of roughly 3x10²¹ ph/s/mm²/mrad²/0.1%BW at 1 keV.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW095

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW097

Design Progress of ALS-U, the Soft X-ray Diffraction Limited Upgrade of the Advanced Light Source

emittance, cavity, storage-ring, vacuum

1639

C. Steier, Ph. Amstutz, K.M. Baptiste, P.A. Bong, E.S. Buice, P.W. Casey, K. Chow, S. De Santis, R.J. Donahue, M.P. Ehrlichman, J.P. Harkins, T. Hellert, M.J. Johnson, J.-Y. Jung, S.C. Leemann, R.M. Leftwich-Vann, D. Leitner, T.H. Luo, O. Omolayo, J.R. Osborn, G. Penn, G.J. Portmann, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, S.P. Virostek, W.L. Waldron, E.J. Wallén
LBNL, Berkeley, California, USA

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-1 approval in 2018 marking the end of its conceptual design phase. The ALS-U design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper presents recent design progress of the accelerator, as well as new results of the mature R&D program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW097

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paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPRB047

Proposal of the Reflection Hard X-Ray Self-Seeding at the SHINE Project

FEL, undulator, photon, polarization

1792

T. Liu, C. Feng
SARI-CAS, Pudong, Shanghai, People’s Republic of China

FEL self-seeding has been demonstrated a great advantage for the generation of a fully coherent and high brightness X-ray pulse experimentally. Generally, transmission monochromators with single crystal are adopted worldwide, such as LCLS, PAL-XFEL and European-XFEL. Recently, the self-seeding scheme based on a reflection monochromator with a double-crystal is proposed and demonstrated at SACLA successfully. In view of several potential advantages of the reflection type, here we give the proposal of the reflection monochromator based self-seeding and enable the application on the SHINE project. This manuscript is mainly focus on monochromator schemes at SHINE, instead of FEL simulations. We will present considerable schemes based on the specific undulator line.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB047

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB074

Start-to-End Simulations of the Compact Light Project Based on an S-Band Injector and an X-Band LINAC

linac, FEL, cavity, electron

1836

E. Marín, R. Muñoz Horta, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi, Turkey
S. Di Mitri
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. Latina
CERN, Geneva, Switzerland
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: This project has received funding from the European Union’s Horizon2020 research and innovation programme under grant agreement No 777431
In this paper we report the start-to-end simulation results of one of the options under consideration for the CompactLight Project (XLS). The XLS is a hard X-ray Free Electron Laser under design, using the latest concepts for bright electron photo injectors, very high-gradient X-band structures, and innovative short-period undulators. Presently there exist various tracking codes to conduct the design process. Therefore identifying the most convenient code is of notable importance. This paper compares the tracking codes, Placet and General Particle Tracer, using the XLS lattice based on a S and X-band Injector. The calculation results in terms of beam quality and tracking performance of a full 6-D simulation are presented.
[*] The CompactLight Design Study Project, IPAC2019 proceedings.

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPRB105

Realizing Low-Emittance Lattice Solutions With Complex Bends

emittance, dipole, quadrupole, sextupole

1906

V.V. Smaluk, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

Funding: Department of Energy Contract No. DE-SC0012704
A concept of new lattice element called "Complex Bend" is recently proposed at NSLS-II. Replacing the regular dipoles in the Double-Bend Achromat lattice by Complex Bends significantly reduces the beam emittance. The first attempt of lattice design for potential NSLS-II upgrade based on Complex Bend, is described. Compared with the current NSLS-II lattice, the new solution modifies only three of the six girders per cell. The linear optics has been matched keeping unchanged the lattice parameters at the straight sections, where the light-generating insertion devices are located. The Complex Bend gradient is limited by 250 T/m assuming possible use of permanent magnets. The lattice provides 65 pm emittance without damping wigglers, use of which results in further decrease of the emittance

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB105

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS027

Progress of J-PARC LINAC Commissioning

linac, rfq, operation, DTL

1990

Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
Z. Fang, K. Futatsukawa, T. Miyao, M. Otani, T. Shibata
KEK, Ibaraki, Japan
T. Ito, A. Miura, T. Morishita, K. Moriya, K. Okabe, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS027

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paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS068

Progress on Design Studies for the ISIS II Upgrade

proton, synchrotron, injection, neutron

2075

J.-B. Lagrange, D.J. Adams, C. Brown, H.V. Cavanagh, I.S.K. Gardner, P.T. Griffin-Hicks, B. Jones, D.J. Kelliher, A.P. Letchford, S. Machida, B.G. Pine, C.R. Prior, C.T. Rogers, J.W.G. Thomason, C.M. Warsop, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak, J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak, J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

ISIS, the spallation neutron source at the Rutherford Appleton Laboratory in the UK, uses a 50 Hz, 800 MeV proton RCS to provide a beam power of 0.2 MW, delivered in 0.4 us long pulses. Detailed studies are now under way for a major upgrade. Accelerator designs using FFAs, conventional accumulator and synchrotron rings are being considered for the required MW beam power. This paper summarises the scope of the different research incorporating results from recent target studies and user consultations. Preliminary results for Fixed Field Alternating gradient (FFA) rings and conventional rings located in the existing ISIS synchrotron hall are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS068

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPMP017

A New Nonlinear Kicker Design and Measurement

kicker, injection, storage-ring, simulation

2342

W.B. Song, W. Liu, Y. Lu, F.L. Shang, L. Shang, Z.B. Sun
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by The National Key Research and Development Program of China(2016YFA0402000) and Pre-research Project of Hefei Advanced Light Source
For the beam injection of HALS, a feasible injection scheme is proposed and a single-pulse nonlinear kicker has been designed for off-axis injection. The kicker has been improved on the basis of the previous designed one, and the structure of the kicker was simulated by OPERA, and the prototype has been processed and measured. The results showed that the kicker designed in this paper has less influence on stored beam and lower difficulty in location.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP017

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paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP019

Physical Design of HEPS Low Energy Transport Line

booster, linac, injection, dipole

2349

Y.M. Peng, C. Meng, H.S. Xu
IHEP, Beijing, People’s Republic of China

he High Energy Photon Source (HEPS), a kilometre-scale storage ring based light source, with emittance less than 60 pm.rad, will be constructed in Beijing, China. It con-sists of a 500 MeV linac, a 500 MeV low energy transport line, a full energy booster synchrotron, two 6- GeV transport lines, a 6 GeV ultra-low emittance storage ring, and the beam line experimental stations. The low energy transport line connecting the linac and the booster. Based on the construction layout restrictions, the beam enve-lopes of the linac and the booster should be matched, and the beam produced by the linac is high efficiently trans-mitted to the booster injection point. HEPS low energy transport line has three functional sections, the achromat injection matching section, the optics matching section and the output matching section. In order to correct the error effects on the beam, 8 BPM are set in the low energy transport line. There are also 6 horizontal correctors and 6vertical correctors for beam trajectory correction. This paper will show the detailed design of HEPS low energy transport line.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP019

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW058

Orbit Correction With Machine Learning

storage-ring, closed-orbit, simulation, coupling

2608

D.J. Xiao, C.P. Chu, Y.S. Qiao
IHEP, Beijing, People’s Republic of China

Orbit correction is usually an important task in the operation of accelerators. In practice, due to various errors, many devices can not operate in ideal state. By correcting the errors of magnets with corrector magnets, the beam can return to the correct position to ensure the stable operation of the accelerator. In the process of orbit correction, inaccurate BPM output will lead to incorrect correction magnet strength setting, so that the orbit correction will be impacted. BPM may make mistakes in the process of signal acquisition and current conversion. A BPM anomaly detection and predict method based on machine learning and its using in orbit correction optimization is reported in this paper. This method does not need to observe the details of BPM system, electronics technology and so on. It can monitor and predict the BPM status directly by machine learning with the information of the beam inferred from BPM and others, and optimize the orbit correction.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW058

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW062

Synchrotron Light Diagnostic Beamline Design for HEPS Storage Ring

emittance, photon, diagnostics, storage-ring

2619

D.C. Zhu, J.S. Cao, Y.F. Sui, J.H. Yue
IHEP, Beijing, People’s Republic of China

Funding: National Nature Science Foundation of China(11605213)
High Energy Photon Source (HEPS) is a 6 GeV ul-tralow-emittance storage ring light source to be built in Beijing, China. With a multiple-bend achromat lattice design, the storage ring is expected to achieve an ul-tralow emittance of 34 pm.rad. The horizontal and verti-cal beam sizes will be in the sub-10 μm level. Beam emit-tance will be measured with x-ray diagnostic beamline at a low dispersion bending magnet source point. A visible light beamline will be designed to measure the bunch length and purity. In this paper, we will introduce the x-ray beamline, which combine with different techniques to resolve beam sizes and emittance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW062

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW110

Feasibility Study of Beam Profile Measurements Using Interferometer and Diffractometer Techniques for ALS-U

electron, synchrotron, storage-ring, radiation

2752

C. Sun, S. De Santis, D. Filippetto, F. Sannibale, C. Steier
LBNL, Berkeley, California, USA

Funding: Work supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
ALS-U is an ongoing upgrade of Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. The upgraded ALS will replace the existing Triple-Bend Achromat (TBA) storage ring lattice with a compact Multi-Bend Achromat (MBA) lattice. This MBA technology allows us to tightly focus electron beams down to about 10 μm to reach diffraction limit in a soft x-ray region. The beam size measurement is a challenging task for this tightly focused beam. The interferometer technique with visible light from synchrotron radiation has been developed in many facilities to measure their beam size at a micrometer-level accuracy. In this paper, we will present the feasibility study of this technique for the ALS-U storage ring beam size measurement.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW110

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPGW124

Spin Response Function for Spin Transparency Mode of RHIC

resonance, collider, polarization, controls

2791

V.S. Morozov, Y.S. Derbenev, F. Lin, Y. Zhang
JLab, Newport News, Virginia, USA
P. Adams, H. Huang, F. Méot, V. Ptitsyn, W.B. Schmidke
BNL, Upton, Long Island, New York, USA
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
H. Huang
ODU, Norfolk, Virginia, USA
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia

Funding: Supported by the U.S. DoE under Contracts No. DE-AC05-06OR23177 and DE-AC02-98CH10886.
In the Spin Transparency (ST) mode of RHIC, the axes of its Siberian snakes are parallel. The spin tune in the ST mode is zero and the spin motion becomes degenerate: any spin direction repeats every particle turn. In contrast, the lattice of a conventional collider determines a unique stable periodic spin direction, so that the collider operates in the Preferred Spin (PS) mode. Contributions of perturbing magnetic fields to the spin resonance strengths in the PS mode are usually calculated using the spin response function. However, in that form, it is not applicable in the ST mode. This paper presents a response function formalism expanded for the ST mode of operation of conventional colliders with two identical Siberian snakes in the highly-relativistic limit. We present calculations of the spin response function for RHIC in the ST mode.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW124

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paper received ※ 01 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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WEPTS011

Intra-Beam Scattering Effect in the SOLEIL Storage Ring Upgrade

emittance, coupling, simulation, cavity

3106

A. Vivoli, A. Bence, P. Brunelle, A. Gamelin, L. Hoummi, A. Loulergue, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

As the work on the design of the upgrade of SOLEIL storage ring advances, the study of the impact of Intra-Beam Scattering (IBS) on the equilibrium emittance is also progressing, showing a significant contribution of this effect. Different measures can be taken to mitigate the emittance dilution, like operating the machine with full transverse coupling and using harmonic cavities to increase bunch length. The calculation of the IBS effect needs then to take into account the different beam dynamics and its effect on the particle distribution. In this paper the current state of the ongoing study is presented, reporting on the results obtained for the different options considered, and comparing the results of different codes and their implicit assumptions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS011

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paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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WEPTS014

Coherent vs Incoherent Effects and Debye Length

space-charge, plasma, focusing, vacuum

3116

G. Franchetti
GSI, Darmstadt, Germany

In this proceeding it is discussed the effect of coherent vs. incoherent effect and discussing the validity of frozen models of space charge according to the Debye length and beam radius. This in view of discussing the relation of IBS and space charge

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS014

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paper received ※ 15 April 2019 paper accepted ※ 28 May 2019 issue date ※ 21 June 2019

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WEPTS022

Stability Tune Diagram of a High-Intensity Hadron Ring

resonance, emittance, space-charge, betatron

3141

H. Okamoto, K. Kojima, Y. Tokashiki
HU/AdSM, Higashi-Hiroshima, Japan

To date, the optimum operating point of a high-intensity hadron ring has been determined on the basis of the conventional incoherent picture. It is generally chosen on the tune diagram such that the so-called "incoherent tune spread" of a stored beam does not overlap with low-order "single-particle resonance" lines. We here propose a new approach to construct the stability tune diagram on the basis of the self-consistent coherent picture. The betatron resonance condition recently conjectured from one-dimensional Vlasov predictions is employed for this purpose, which predicts the existence of twice as many resonance stop bands as expected from the well-known incoherent resonance condition at high beam density *,**. The proposed general rules for the stability-chart construction are very simple and free from any model-dependent unobservables like space-charge-depressed incoherent tunes. As an example, we apply the present rules to the lattice of the rapid cycling synchrotron at J-PARC and explain why the operating bare tunes of this machine have been chosen slightly below 6.5 in both transverse directions.
* K. Ito et al., Phys. Rev. Accel. Beams 20, 064201 (2017).
** H. Okamoto and K. Yokoya, Nucl. Instrum. Meth. A 482, 51 (2002).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS022

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paper received ※ 09 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS026

Generalised Scattering Module in SixTrack 5

scattering, target, experiment, proton

3156

K.N. Sjobak
University of Oslo, Oslo, Norway
H. Burkhardt, R. De Maria, V.K.B. Olsen
CERN, Geneva, Switzerland

Funding: Research Council of Norway, project 255196, and HL-LHC WP8
A generalised scattering module has recently been added to SixTrack. This module enables the use of arbitrary generators and target profiles. Presently, a simple model of elastic scattering and a coupling to Pythia8 have been implemented. This makes it possible to use SixTrack for studies of aperture losses and beam lifetime as a result of beam–beam scattering.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS026

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS028

Transverse-Longitudinal Coupling for Harmonic Generation and Bunch Length Manipulation

emittance, bunching, coupling, storage-ring

3160

X.J. Deng, W.-H. Huang, C.-X. Tang, Y. Zhang
TUB, Beijing, People’s Republic of China
A. Chao
SLAC, Menlo Park, California, USA

A general harmonic generation and bunch length manipulation scheme using transverse-longitudinal coupling is presented. The method makes use of the freedom in projecting the three beam eigen-emittances into different physical dimensions. A realization of this coupling lattice, a PEHG variant, is given as an example. For the purpose of harmonic generation and bunch compression, this method is advantageous when the transverse emittance is small. The combination with sawtooth waveform modulation is proposed to boost the bunching further. Transverse-longitudinal coupling in storage rings are briefly discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS028

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPTS047

Space Charge Driven Resonances in the CERN PS

resonance, space-charge, brightness, simulation

3216

F. Asvesta
NTUA, Athens, Greece
H. Bartosik, A. Huschauer, Y. Papaphilippou
CERN, Geneva, Switzerland

In the CERN Proton Synchrotron space charge driven resonances are excited around the operational working point due to the periodicity of the optics functions. In this paper, the resonances are studied using analytical methods, i.e. the evaluation of the resonance driving terms connected to the space charge potential of Gaussian distributions. Furthermore, the resonances are characterized in measurements and simulations for various beams. The beams considered are different in terms of brightness, in order to study the dependence of the resonance strength on the space charge force.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS047

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paper received ※ 17 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPTS056

Can a Paul Ion Trap Be Used to Investigate Nonlinear Quasi-Integrable Optics?

octupole, optics, experiment, quadrupole

3251

L. Martin, S.L. Sheehy
JAI, Oxford, United Kingdom
D.J. Kelliher
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Here we describe the design of an experimental setup using the IBEX Paul trap to test nonlinear quasi-integrable optics, an accelerator lattice design to create stable high intensity beams. In 2010 Danilov and Nagaitsev found a realisable nonlinear potential which can create integrable optics in an accelerator when embedded in a linear lattice that provides round beams. This concept will be tested in the IOTA ring at Fermilab. It is important to further test this concept over a wide parameter range, preferably in a simplified experimental setup such as IBEX. The IBEX Paul trap is capable of replicating the transverse dynamics of a high intensity accelerator without dispersion or chromaticity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS056

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS060

Multi-objective Optimization of 3D Beam Tracking in Electrostatic Beamlines

simulation, experiment, quadrupole, storage-ring

3263

V. Rodin, J.R. Hunt, J. Resta-López, B. Veglia, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J.R. Hunt, J. Resta-López, V. Rodin, B. Veglia, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: *This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 721559.
After CERN’s Long Shutdown 2 (LS2) the Extra Low Energy Antiproton (ELENA) ring will begin providing extremely low energy (100 keV) antiproton beams to the antimatter experiments in the AD hall. To allow for simultaneous operation and guarantee maximum efficiency, all transfer lines will be based on electrostatic optics and short pulse (∼100 ns) deflectors. Currently, only a limited number of simulation codes allow a realistic representation of these elements, limiting the capabilities for beam quality optimization. In this contribution methods for modelling realistic electrostatic optical elements and perform 3D tracking studies through these are presented. A combination of finite element methods and experimental measurements are used along with a modified version of the G4Beamline and BMAD codes. Multi-objective optimization techniques are then applied to optimize beam transfer and beam quality at various points along the transfer lines.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS060

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paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPTS062

Zgoubi Status: Improved Performance, Features, and Graphical Interface

interface, closed-orbit, linac, pick-up

3271

D.T. Abell, P. Moeller, R. Nagler, B. Nash, I.V. Pogorelov
RadiaSoft LLC, Boulder, Colorado, USA
I.B. Beekman
ParaTools, Inc., Eugene, Oregon, USA
F. Méot
BNL, Upton, Long Island, New York, USA
D.W.I. Rouson
Sourcery Institute, Oakland, California, USA

Funding: This work was supported in part by the US Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-SC0017181.
The particle tracking code Zgoubi * has been used for a broad array of accelerator design studies, including FFAGs and EICs. Zgoubi is currently being used to evaluate the spin polarization performance of proposed designs for both JLEIC ** and eRHIC ***, and to prepare for commissioning the CBETA BNL-Cornell FFAG return loop ERL ****. We describe our on-going work on several fronts, including efforts to parallelize Zgoubi using new features of Fortran 2018 *****, and a new implementation of Zgoubi’s particle update algorithm. We also describe a new, web-based graphical interface for Zgoubi.
* F. Méot, FERMILAB-TM-2010, 1997
** J. Martinez-Marin et al., IPAC18, MOPMF004
*** V.H. Ranjbar et al., IPAC18, MOPMF016
**** F. Méot et al., NIM-A 896:60, 2018
***** wg5-fortran.org/f2018.html

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPTS070

First Measurements of Nonlinear Decoherence in the IOTA Ring

kicker, experiment, damping, optics

3286

C.C. Hall, D.L. Bruhwiler, J.P. Edelen
RadiaSoft LLC, Boulder, Colorado, USA
N. Kuklev
University of Chicago, Chicago, Illinois, USA
A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: This work has been supported by the U.S. Department of Energy Office of Science, Office of High Energy Physics under Award No. DE-SC00111340
The Integrable Optics Test Accelerator (IOTA), at Fermi National Laboratory is aimed at testing nonlinear optics for the next generation of high intensity rings. Through use of a special magnetic element the ring is designed to induce a large tune spread with amplitude while maintaining integrable motion. This will allow for the suppression of instabilities in high-intensity beams without significant reduction in dynamic aperture. One important aspect of this is the nonlinear decoherence that occurs when a beam is injected off axis or receives a transverse kick while circulating in the ring. This decoherence has been studied in detail, with simulations, for protons in IOTA both with and without space-charge. However, it has yet to be demonstrated experimentally. During the first phase of the IOTA experimental program, the ring is operated with 100 MeV electrons, allowing for the study of nonlinear optics without the complications introduced by space charge. Here we present measurements taken during the IOTA commissioning, and an analysis of the results.

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paper received ※ 15 May 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, dynamic-aperture, 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.

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPTS093

Emittance Preservation for LCLS-II-HE Project

emittance, electron, laser, space-charge

3333

J. Wu, T.O. Raubenheimer, M.D. Woodley
SLAC, Menlo Park, California, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: The work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164.
A small transverse slice emittance at the undulator entrance is essential for high performance of the free electron laser. To achieve this, preservation of the phase space density of the electron bunch during acceleration and compression is absolutely necessary. The LCLS-II-HE is designed to transport a 100 pC bunch with an emittance of ~0.3 mm-mrad with minimal emittance dilution. However, in simulations starting from a normalized emittance on the order of 0.1 mm-mrad, the emittance growth is significant. In this paper, the sources of emittance growth are studied along the accelerator, in particular, around the laser-heater, the two bunch compressors. We have investigated mechanisms of emittance growth such as space charge, coherent synchrotron radiation, chromatic aberration, and spurious dispersion. Due to the extremely small emittance from the injector, 3-D space charge effect is important to determine the space charge dominated region and emittance dominated region. With this understanding, emittance preservation schemes are proposed. Studies are carried out with IMPACT simulation code, as well as ASTRA and ELEGANT.

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paper received ※ 23 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPTS103

Optimization of a Low-Alpha Lattice for the HLS-II Storage Ring

storage-ring, quadrupole, dynamic-aperture, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS103

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paper received ※ 29 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB062

New Orbit Correction Method Based on SVDC Algorithm for Ring Based Light Sources

feedback, controls, simulation, photon

3943

X.Y. Huang, J.S. Cao, Y.Y. Du, Y.H. Lu, H.Z. Ma, Y.F. Ma, Y.F. Sui, S.J. Wei, Y. Wei, Q. Ye, X.E. Zhang, D.C. Zhu
IHEP, Beijing, People’s Republic of China

Funding: Union Foundation of excellent post-doctoral of China
Orbit feedback system is essential for realizing the exceeding beam stability in modern ring based light sources. Most advanced light sources adopt the global correction scheme by using singular value decomposition (SVD) algorithm. In this paper, a new SVD with constraints method (SVDC) is proposed to correct the global and local orbit simultaneously. Numerical simulations are presented with the case of High Energy Light Source (HEPS) by comparing classic algorithms. The results show that SVDC is very effective for orbit correction and very easy to implement.

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paper received ※ 09 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS021

Magnets for Elettra 2.0

quadrupole, sextupole, optics, ion-effects

4152

D. Castronovo, E. Karantzoulis
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

After 25 years of faithfully serving the user community with excellent results, Elettra need a major upgrade with a new compact latice that will replace the existing double bend achromat for the reducing of the horizontal emittance and the increasing of the brilliance and coherence of the X-ray beam. This paper report the magnetic design development and optimisations carried out in order to satisfy the layout feasibility and the magnet strengths.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS024

Magnet Developments and Precise Alignment Schemes for SPring-8-II

alignment, multipole, sextupole, quadrupole

4158

K. Fukami, T. Aoki, N. Azumi, H. Kimura, S. Matsubara, S. Takano, T. Taniuchi, T. Watanabe, K. Yanagida, C. Zhang
JASRI, Hyogo, Japan
N. Azumi, K. Fukami, H. Kimura, S. Matsui, S. Takano, T. Watanabe
RIKEN SPring-8 Center, Hyogo, Japan
S.I. Inoue, T. Kai, J. Kiuchi
SES, Hyogo-pref., Japan

The magnet lattice design of the SPring-8 upgrade, SPring-8-II, is a five bend achromat composed of one normal and four longitudinal gradient bending magnets. Permanent magnet has been chosen for both types of the dipoles, and the high gradient multipole magnets are all electromagnets. This presentation will overview the magnet developments and precise alignment schemes for SPring-8-II, focusing specifically on the following features. Temperature insensitive magnetic circuits with a function of fine magnetic field tuning have been developed for the permanent magnet dipoles. Narrow bore multipole magnets with compact coil assemblies have been designed. We optimized the shimming for enough good field regions, and minimized ohmic loss at the coils for suppressing thermal deformation. To improve the accuracy of vibrating wire magnet alignment, practical wire sag distributions have been quantitatively evaluated. In 2018, a test half-cell was constructed by which the feasibilities of the magnets and the overall alignment precisions including the effects of the thermal deformation of magnets, a repeatability of magnet reassembly has been confirmed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS024

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paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS048

Design of Longitudinal Gradient Bending Magnet of HALS

multipole, permanent-magnet, synchrotron, ECR

4215

B. Zhang, C. Chen, Z.L. Ren, X.Q. Wang, H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Hefei Advanced Light Source (HALS) is a diffraction limited light source, which was proposed and expected to be built in the next few years by National Synchrotron Radiation Laboratory (NSRL) of China. Just like other new light sources, longitudinal gradient bending magnet (LGB) will be adopted to suppress the beam emittance. The magnet consists of 7 modules with different magnet-ic field. Each module has yoke and poles with the same size but different amount of permanent magnet to gener-ate field gradient. FeNi alloy is used to shunt magnetic flux and thus improve the temperature stability. Correc-tor coil or movable wedge can be used to adjust the field. Impact of magnetization direction error of permanent magnet block and parallelism error of poles on multi-poles is also evaluated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS048

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS080

Novel Technique Ion Assisted In-Situ Coating of Long, Small Diameter, Accelerator Beam Pipes with Compacted Thick Crystalline Copper Film

cathode, cryogenics, vacuum, plasma

4301

A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, W. Fischer, G.T. McIntyre, S. Verdú-Andrés
BNL, Upton, Long Island, New York, USA
A.X. Custer, M.Y. Erickson, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
Although great progress was made with in-situ copper coating, by magnetron sputtering, to address the high room temperature resistivity, literature indicates that conventionally deposited thick copper films do not retain the same RF conductivity at cryogenic temperatures, since straightforward deposition tends to result in films with columnar structure and other lattice defects, which cause significant conductivity degradation at cryogenic temperatures. We utilize energetic ions for ion assisted deposition (IAD) to reduce lattice imperfections, for coating. IAD that can in-situ coat long small diameter tubes with compacted crystalline structure thick copper films has been developed. Moreover, development of techniques and devices can resurrect IAD for other applications, which have been impractical and/or not viable economically. Comparison of conductivity at cryogenic temperatures between straight magnetron physical vapor deposition and IAD will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS080

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS081

Novel Apparatus and Technique for Measuring RR Resistivity of Tube Coatings at Cryogenic Temperatures

cryogenics, cavity, experiment, vacuum

4304

A. Hershcovitch, J.M. Brennan, R. Than, S. Verdú-Andrés, Q. Wu
BNL, Upton, Long Island, New York, USA
A.X. Custer, M.Y. Erickson, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A unique apparatus for measuring RF resistivity of tubes and coated tubes at cryogenic temperatures is operational at BNL, which to our knowledge is the first of its kind. A folded quarter wave resonator structure of 300 mm length accesses a wide range of frequencies. The structure is cooled in liquid He bath at 4 K. All internal resonator components (except for test samples) were fabricated out of superconducting materials. Consequently, when the resonator is cooled, the bulk of the losses are due to the copper coating. The RF resistivity is determined from Q measurements, since for a fixed geometry the quality factor of a resonant cavity is proportional to the square root of the conductivity. The RF input loop and the output signal antenna are adjustable when cold via bellows to control matching to each cavity mode. The Q values of 10 resonant modes between 180 and 2500 MHz are deduced from the bandwidth of the S21 response Network Analyzer measurements. CST MicroWave Studio is used to extract the resistivity of the samples from the Q measurements. Resistivity results of solid Cu tube, 2, 5, & 10 μm Cu coated 316LN stainless steel RHIC beam tubes will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS081

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS094

High Gradient Quadrupoles for Low Emittance Synchrtrons

quadrupole, dipole, focusing, vacuum

4332

S.K. Sharma, T.V. Shaftan, V.V. Smaluk, C.J. Spataro, T. Tanabe, G.M. Wang
BNL, Upton, Long Island, New York, USA
N.A. Mezentsev
BINP SB RAS, Novosibirsk, Russia

A new lattice design has been proposed recently based on a Complex-Bend concept [1,2] for low emittance syn-chrotrons. The dipoles of a standard DBA lattice are replaced in the Complex Bend by high-gradient (~ 450 T/m) quadrupoles interleaved between discrete dipoles. In another version of the Complex Bend [3] the high gradient quadrupoles are displaced transversely along the beam trajectory to generate the required dipole field. In the latter version the quadrupole strength is reduced to ~ 250 T/m for a lattice that will conform to the layout of the existing NSLS-II 3-GeV storage ring. In this paper we present conceptual designs of a Halbach permanent-magnet (PM) quadrupole, a hybrid PM quadrupole, and a superconducting quadrupole, that can produce the de-sired quadrupole strengths for the Complex Bend appli-cation. REFERENCES [1] T. Shaftan, V. Smaluk and G. Wang, ’The Concept of Com-plex Bend’, NSLS-II Tech note No. 276, Jan 2018. [2] G. Wang et al., ’Complex Bend: Strong-focusing magnet for low emittance synchrotrons’, Physical Review Accelerators and Beams, 21, 100703 (2018). [3] G. Wang et al., ’Complex Bend II’, paper submitted to Physi-cal Review Accelerators and Beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS094

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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