IPAC2018 - List of Keywords (storage-ring)

Paper	Title	Other Keywords	Page
MOPMF014	Polarization at eRHIC Electron Storage Ring, an Ergodic Approach	polarization, electron, simulation, lattice	112
	F. Méot 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. Based on considerations of ergodicity of the dynamical system of an electron bunch at equilibrium, the preservation of polarization in an electron storage ring is estimated from the tracking of a very limited number of electrons. This has a substantial impact on required High Power Computing resources, in noticeable contrast with the method generally used that tracks tens of electron bunches, each comprised of thousands of particles, for several thousands of turns. It is also shown that a minimum number of tracking turns is required in order to ensure the numerical convergence of the linear regressions that yield depolarizing time constant values from tracking, in both methods.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF014
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MOPMF028	A Superconvergent Algorithm for Invariant Spin Field Stroboscopic Calculations	simulation, resonance, polarization, lattice	145
	D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: National Science Foundation and the Department of Energy Stroboscopic averaging can be used to calculate the invariant spin field \bfn for particles with a finite oscillation amplitude in phase space. The standard technique starts with making a guess for \bfn(\bfr), which is a function of the phase space position \bfr. By tracking a particle's orbital position forward in time and then projecting the guessed \bfn backwards to the starting phase space point, the average of the backward projected spins will converge to the invariant spin direction linearly as 1/N where N is the number of turns tracked. The convergence can be accelerated by an iterative method that uses an approximate invariant spin field constructed by averaging the calculated spin field over points that are close in orbital phase space. This superconvergent algorithm has been built into a new program based upon the Bmad toolkit for charged particle and X-ray simulations.
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MOPMF071	Polarization Studies for the eRHIC electron Storage Ring	polarization, electron, coupling, solenoid	292
	E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA S. Tepikian BNL, Upton, Long Island, New York, USA
	Funding: Manuscript authored by Fermi Res. All., LLC under Contr. No. DE-AC02-07CH11359 and Brookhaven Sc. Ass., LLC under Contr. No. DE-AC02-98CH10886 with the U.S. DOE, Office of Science, Office of HEP. A hadron/lepton collider with polarized beams has been under consideration by the scientific community since some years, in the U.S. and Europe. Among the various proposals, those by JLAB and BNL with polarized electron and proton beams are currently under closer study in the U.S. Experimenters call for the simultaneous storage of electron bunches with both spin helicity. In the BNL based Ring-Ring design, electrons are stored at top energy in a ring to be accommodated in the existing RHIC tunnel. The transversely polarized electron beam is injected into the storage ring at variable energies, between 5 and 18 GeV. Polarization is brought into the longitudinal direction at the IP by a couple of spin rotators. In this paper results of first studies of the attainable beam polarization level and lifetime in the storage ring at 18 GeV are presented.
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TUYGBD3	eRHIC Design Status	electron, hadron, luminosity, proton	628
	V. Ptitsyn, G. Bassi, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, A. Blednykh, J.M. Brennan, S.J. Brooks, K.A. Brown, K.A. Drees, A.V. Fedotov, W. Fischer, D.M. Gassner, W. Guo, Y. Hao, A. Hershcovitch, H. Huang, W.A. Jackson, J. Kewisch, C. Liu, H. Lovelace III, Y. Luo, F. Méot, M.G. Minty, C. Montag, R.B. Palmer, B. Parker, S. Peggs, V.H. Ranjbar, G. Robert-Demolaize, S. Seletskiy, V.V. Smaluk, K.S. Smith, S. Tepikian, P. Thieberger, D. Trbojevic, N. Tsoupas, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman, W. Zhang BNL, Upton, Long Island, New York, USA E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The electron-ion collider eRHIC aims at a luminosity around 10³⁴cm^-2sec^-1, using strong cooling of the hadron beam. Since the required cooling techniques are not yet readily available, an initial version with a peak luminosity of 3*10³³cm^-2sec^-1 is being developed that can later be outfitted with strong hadron cooling. We will report on the current design status and the envisioned path towards 10³⁴cm^-2sec^-1 luminosity.
	Slides TUYGBD3 [11.790 MB]
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TUPAF078	Recent Results of HESR Original Stochastic Cooling Tanks at COSY	kicker, pick-up, experiment, hardware	913
	R. Stassen, B. Breitkreutz, N. Shurkhno FZJ, Jülich, Germany
	The High Energy Storage Ring (HESR) of the FAIR project at GSI Darmstadt will be very important for different scientific programs due to the modularized start version of FAIR. Stochastic cooling together with barrier bucket operation will be the key component to fulfill the requirements of the different experiments. First pickup and first kicker of the HESR stochastic cooling system have been installed into the COSY accelerator at FZJ Jülich. COSY is well suited to test the performance of the HESR stochastic cooling hardware at different energies and variable particle numbers. The novel dedicated HESR-structures were already successfully tested at the Nuclotron in Dubna for longitudinal cooling and during a beam time 2017 for transverse cooling at COSY. The results of the last stochastic cooling beam time will be presented as well as the first use of GaN based amplifiers in a stochastic cooling system. The HESR needs fast transmission-lines between PU and KI. Beside air-filled coax-lines, optical hollow fiber-lines are very attractive. First results with such a hollow fiber used for the transverse signal path will be presented.
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TUPAL028	New Feature of the Oscillating Synchrotron Motion Derived from the Hamiltonian Composed of Three Motions	synchrotron, betatron, closed-orbit, experiment	1060
	K. Jimbo Kyoto University, Kyoto, Japan
	The equation for the synchrotron motion was derived from the Hamiltonian, which was composed of coasting, betatron and synchrotron motions. The betatron oscillation is　the horizontal oscillation. The synchrotron oscillation is not only an oscillation of the revolution frequency but also an oscillation of the average radius. The synchrotron oscillation is both longitudinal and horizontal oscillations and it is possible to exchange energy with the betatron oscillation. The synchrotron oscillation occurs under a constant particle velocity and the Hamiltonian is conserved. K.Jimbo, Physical Review Special Topics - Accelerator and Beams 19, 010102 (2016).
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TUPMF008	Design, Construction, and Magnetic Field Measurements of a Helical Superconducting Undulator for the Advanced Photon Source	undulator, photon, electron, experiment	1263
	M. Kasa, S.J. Bettenhausen, J.D. Fuerst, E. Gluskin, Q.B. Hasse, Y. Ivanyushenkov, I. Kesgin, Y. Shiroyanagi, E. Trakhtenberg ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. A helical superconducting undulator (HSCU) was developed and installed at the Advanced Photon Source (APS). Implementation of a unique design of the helical coil former allowed for a compact turn around scheme of the conductor at the ends of the device during winding. Inherent to the coil winding design was the gradual reduction of the magnitude of the magnetic field at the ends of the device. The coil former design along with the magnetic measurement results will be described.
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TUPMF012	Determination of the Ground Motion Orbit Amplification Factors Dependence on the Frequency for the APS Upgrade Storage Ring	ground-motion, factory, lattice, simulation	1272
	V. Sajaev, C.A. Preissner 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. The Advanced Photon Source (APS) is pursuing an upgrade to the storage ring that will provide electron beam with extremely low emittance. To allow users to take advantage of this small beam size, the beam orbit motion has to be kept stable to within a fraction of the beam size, which translates to sub-micron orbit stability requirement. Ground motion provides significant contribution to the overall expected beam motion, especially at lower frequencies where the ground motion has larger amplitudes. At the same time, the lattice amplification factors reduce when the ground motion becomes coherent at low frequencies. In this paper, we will present simulation of the lattice amplification factor dependence on the ground motion coherence length and show results of the ground motion coherence measurements at APS. After that, we will determine the lattice amplification factors dependence on the ground motion frequency, that can be used to calculate the expected effect of the ground motion on the orbit stability.
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TUPMF013	Optimizations of Nonlinear Beam Dynamics Performance on APS-U Lattice	lattice, MMI, sextupole, multipole	1276
	Y.P. Sun, M. Borland 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. For next-generation storage ring light sources, such as the Advanced Photon Source (APS) Multi-Bend Achromat (MBA) upgrade, the strong nonlinearities introduced by the strong chromaticity sextupoles plus the small physical apertures make it challenging to achieve large dynamic acceptance (DA) and long Touschek lifetime, even when using the on-axis swap-out injection scheme. Several different methods have been explored for nonlinear dynamics optimization. The optimization objectives variously include the chromaticities up to third order, resonance driving and detuning terms, on- and off-momentum dynamic acceptance, chromatic and geometric tune footprint, local momentum acceptance (LMA), variation of betatron oscillation invariant, Touschek lifetime, etc. In addition, optimization can be performed without errors, with selected random errors, and with sets of errors that reflect post-commissioning conditions. In this paper, these different optimization methods are compared for the nonlinear beam dynamics performance of the Advanced Photon Source upgrade (APS-U) lattice, in terms of the dynamic acceptance, local momentum acceptance, and other performance measures. The impact from different error sources is also studied.
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TUPMF018	Simulation Studies of the Helical Superconducting Undulator Installed at APS	multipole, simulation, undulator, operation	1290
	A. Xiao, V. Sajaev, Y.P. Sun ANL, Argonne, Illinois, USA
	A multi-year project at APS has resulted in construction of a helical superconducting undulator (HSCU) for installation in the ring. Before installation, simulation studies were done to ensure that APS performance will not be compromised. This paper describes the method used for calculating the HSCU's perturbation effects and the simulation results for both calculated and measured field map. Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
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TUPMF022	Electron Beam Scanning in the Delta-Type Undulators for Sirius	undulator, electron, radiation, polarization	1300
	A. B. da Cruz, L. Liu LNLS, Campinas, Brazil
	We report on simulation studies to analyze the possibility of scanning the electron beam, and not scanning the sample, in CDI experiments using a Delta-Type undulator in the 3GeV Sirius electron storage ring presently under construction at LNLS. This would allow much faster scans in diffraction limited storage rings such as Sirius. We study displaced beam trajectories through the undulators and analyze the effects on the emitted radiation. It is possible to show that displacements on the order of ± 500 micrometers around the center will introduce variations in the radiation spectrum that are less that 1 per cent and thus acceptable for Coherent Diffraction Imaging experiments.
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TUPMF036	Top Off of NSLS-II with Inefficient Injector	booster, injection, linac, operation	1327
	R.P. Fliller, A.A. Derbenev, V.V. Smaluk, X. Yang BNL, Upton, Long Island, New York, USA
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The NSLS-II is a 3 GeV storage with a full energy injector capable of top off injection. The injector consists of a 200 MeV linac injecting a 3 GeV booster. Recent operational events have caused us to investigate 100 MeV injection into the booster. As the booster was not designed for injection at this low energy, beam loss is observed with this low energy booster injection. This beam loss not only results of overall charge loss from the train, but a change in the overall charge distribution in the bunch train. In this paper we discuss the performance of injecting into the storage ring with the inefficient charge transfer through the injector. The changes to the top off method are discussed, as well as the achieved storage ring current stability and fill pattern.
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TUPMF046	The Injection and Extraction Design of the Booster for the HEPS Project	injection, extraction, kicker, booster	1356
	Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu IHEP, Beijing, People's Republic of China
	The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.
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TUPMF049	Evolution of the Lattice Design for the High Energy Photon Source	lattice, emittance, injection, photon	1363
	G. Xu, S.Y. Chen, Y. Jiao, J.L. Li, Y.M. Peng, Q. Qin, J.Q. Wang, C.H. Yu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is a high-energy, ultralow-emittance, kilometer-scale storage ring light source to be built in China. The HEPS lattice design has been started since 2008. In this paper we will review the evolution of the HEPS lattice design over the past ten years, focusing mainly on the linear optics design and nonlinear optimization.
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TUPMF050	DA Optimization Experiences in the Heps Lattice Design	lattice, sextupole, emittance, photon	1367
	Y. Jiao, G. Xu IHEP, Beijing, People's Republic of China
	In the past decade, the so-called diffraction-limited storage ring (DLSR) light sources were proposed, promising much better radiation performance than available in the existing third generation light sources. Regarding the very strong focusing and chromatic sextupoles that required for reaching an ultralow emittance, to optimize the nonlinear dynamics and achieve an adequate dynamic aperture is an important topic in a DLSR design. In this paper we will present some tips distilled from the DA optimization experience of the High Energy Photon Source over the past ten years, hoping it could provide some aids to other ultralow-emittance designs.
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TUPMF052	Progress of Lattice Design and Physics Studies on the High Energy Photon Source	lattice, booster, injection, emittance	1375
	G. Xu, X. Cui, Z. Duan, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, 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 ultralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physical design and studies on HEPS over the past one year, covering issues of storage lattice design and optimization, booster design, injection design, collective effects, error study, insertion device effects, beam lifetime, etc.
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TUPMF054	Performance Comparison of Different Ultralow Emittance Unit Cells	emittance, lattice, dipole, quadrupole	1382
	Y. Jiao, X.Y. Li, G. Xu IHEP, Beijing, People's Republic of China
	The available minimum emittance of a storage ring and the ring performance is closely related to the unit cell of the lattice. Up to now, several ultralow-emittance unit cells have been proposed and applied in the lattice design of the diffraction-limited storage ring light sources. In this study we quantitatively compared the performance of three typical unit cells, based on mainly the parameters of the High Energy Photon Source. The results indicate that the modified-TME unit cell with antibend and longitudinal gradient dipole allows the lowest possible emittance, given a long enough cell length.
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TUPMF058	Conceptual Design of HEPS Injector	booster, injection, linac, dipole	1394
	J.L. Li, H. Dong, Z. Duan, Y.Y. Guo, D.Y. He, Y. Jiao, W. Kang, C. Meng, S. Pei, Y.M. Peng, J.R. Zhang, P. Zhang, Z.S. Zhou IHEP, Beijing, People's Republic of China
	Abstract The High Energy Photon Source (HEPS) will be constructed in the following few years. The light source is comprised of an ultra-low emittance storage ring and a full energy injector. The energy of the storage ring is 6 GeV. The injector is comprised of a 500 MeV linac, a 500 MeV to 6 GeV booster synchrotron and transport lines connecting the machines. In the present design, the linac uses normal conducting S-band bunching and accelerating structures. The booster adopts FODO cells, has a circumference of about 454 m and an emittance lower than 40 nmrad. The injector can provide a single-bunch charge up to 2 nC at 6 GeV for the storage ring. This paper briefly introduces the conceptual design of the injector of the HEPS.
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TUPMF062	Status of HEPS Booster Lattice Design and Physics Studies	booster, injection, lattice, extraction	1407
	Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, C. Meng, S.K. Tian, H.S. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) with an ul-tralow emittance is proposed to be built in Beijing, Chi-na. It will utilize a booster as its full energy injector. On-axis swap-out injection is chosen as the baseline injec-tion scheme for the storage ring. As required by the stor-age ring, a beam with a bunch charge up to 2.5 nC is needed to be injected in the booster. However, limited by the transverse mode coupling instability (TMCI), such a high bunch charge is challenging. To overcome this problem, a lattice with a considerable large momentum compaction factor is designed. This paper reports the lattice design and physics studies of the HEPS booster, including injection and extraction design, error studies, eddy current effects, collective effects, and so on.
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TUPMF063	The Considerations of Improving TMCI Threshhold on HEPS Booster	booster, lattice, linac, injection	1411
	Y.M. Peng, J.L. Li, C. Meng, S. Pei, H.S. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is proposed in Beijing, China. The on-axis swap-out injection scheme will be used in the storage ring mainly because of the small dynamic aperture. Therefore, the booster needs to store more than 2.5 nC bunch charge. Under this requirement, the transverse mode coupling instability (TMCI) at the injection energy becomes the bunch charge restriction in the booster. Several changes in booster and linac for improving bunch charge threshold limited by TMCI are considered. The details will be expressed in this paper.
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TUPMF069	Low Gain FEL Oscillator Option for PETRA IV	FEL, undulator, emittance, electron	1420
	I.V. Agapov DESY, Hamburg, Germany Y.-C. Chae ANL, Argonne, Illinois, USA W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Next generation synchrotron storage rings will have electron beam density approaching that necessary for driving an XFEL. It falls short of the quality required for the high-gain x-ray regime above 1 keV, mainly due to the large energy spread and small peak current, bit is sufficient to reach low-gain regime. Here we explore the parameter space of a low gain XFEL oscillator, to establish the feasibility range of such a device for the Petra upgrade project.
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TUPMK001	Removal of RF-Fingers at the Edges of the Injection Kickers	impedance, resonance, kicker, injection	1485
	T.F.G. Günzel, N. Ayala, F.F.B. Fernández, U. Iriso, M. Pont ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	The ALBA storage ring injection kickers are equipped with RF-fingers to close a 2.5 mm gap between the ceramic tube and the metallic flange. After two distortion incidents that required the replacement of the fingers, their removal was decided. The decision could be supported by the observation that most of the additional impedance is created above the cut-off frequency of the beam pipe. This was later confirmed by a temperature decrease in that zone after the removal. Furthermore it was checked that the thresholds of the longitudinal coupled bunch instabilities of modes trapped around the resulting open gap are above the maximal applied beam current of 400 mA.
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TUPMK003	Advances in the Sirius Delta-Type Undulator Project	undulator, lattice, polarization, MMI	1491
	L.N.P. Vilela, R. Basílio, J.F. Citadini, J.R. Furaer, F. Rodrigues LNLS, Campinas, Brazil
	The Delta undulator is a compact adjustable-phase insertion device that provides full light polarization control. Five undulators of this type will be installed in the initial operation phase of Sirius, the new 4th generation synchrotron light source that is being built by the Brazilian Synchrotron Light Laboratory (LNLS). In this work we present the recent advances in the development of Sirius Delta-type undulator, the studies of the effects of this device in the storage ring beam dynamics and assembly and measurements strategies.
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TUPMK004	Using Decoherence to Prevent Damage to the Swap-Out Dump for the APS Upgrade	simulation, emittance, kicker, electron	1494
	M. Borland, J.C. Dooling, R.R. Lindberg, V. Sajaev, A. Xiao 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. The Advanced Photon Source (APS) is pursuing an upgrade of the storage ring to a hybrid seven-bend-achromat* design, which will operate in swap-out mode. The ultra-low emittance (about 30 pm in both planes) combined with the desire to provide high charge (15 nC) in individual bunches, entails very high energy density in the beam. Simple estimates, confirmed by simulation, indicate that interaction of such a bunch with the dump material will result in localized melting. Over time, it is possible that the beam would drill through the dump and vent the ring vacuum. This would seem to prevent extraction and dumping of bunches as part of swap out, and also suggests that transferring of bunches out of the ring carries significant risk. We devised an idea for using a pre-kicker to cause decoherence of the target bunch emittances, making it safe to extract. Simulations show that the concept works very well. *L. Farvacque et al., IPAC13, 79 (2013).
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TUPMK010	Differences in Current Dependent Tune Shifts Measured by Direct or ORM Based Methods	vacuum, impedance, optics, wakefield	1510
	Y.E. Tan, R.T. Dowd AS - ANSTO, Clayton, Australia
	The change in the tunes as a function of total beam current is a well documented effect and has been attributed to quadrupole like self induced wakefields. Theoretical models presented by others have utilised direct methods (spectrum analyser) to measure the tunes in the analysis. In this report we shall present observations that show the ORM method, Linear Optics from Closed Optics (LOCO), and direct methods have significantly different tune gradients. The different tune gradients is attributed to the static (ORM) and dynamic (direct) nature of the measurements where in the static case the vacuum chamber is to be considered as a thin wall while in the dynamic case the vacuum chamber wall is to be considered as a thick wall.
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TUPMK014	Dipole Fringe Field Analysis of the NSLS-II Storage Ring	dipole, optics, lattice, simulation	1519
	J. Choi, Y. Hidaka, T.V. Shaftan, C.J. Spataro, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: DOE Contract No. DE-SC0012704 In the NSLS-II storage ring, the effect of the dipole fringe field is not negligible and was considered already at the design phase. Especially in the vertical direction, the standard simulation codes are using the parameter called FINT (fringe Field INTegral) and, if there is no specific information, it is usually set to 0.5 which is considered as the reasonable average. With the hall-probe measurement data of the NSLS-II storage ring dipoles, we evaluated measured FINTs and applied them to the beam simulation. The paper shows the resulting FINTs and their effects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK014
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TUPMK015	Initial Studies into Longitudinal Ionization Cooling for the Muon g-2 Experiment	emittance, simulation, experiment, target	1522
	J. Bradley Edinburgh University, Edinburgh, United Kingdom J.D. Crnkovic BNL, Upton, Long Island, New York, USA D. Stratakis, M.J. Syphers Fermilab, Batavia, Illinois, USA M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA
	Fermilab's Muon g-2 experiment aims to measure the anomalous magnetic moment of the muon to an unprecedented precision of 140 ppb. It relies on large numbers of muons surviving many turns in the storage ring without colliding with the sides, at least long enough for the muons to decay. Longitudinal ionization cooling is introduced with respect to Fermilab's Muon g-2 experiment in an attempt to increase storage and through this the statistics and quality of results. The ionization cooling is introduced to the beam through a material wedge, an initial simulation study is made into the positioning, material, and geometrical parameters of this wedge using G4Beamline. Results suggest a significant increase of 20 - 30% in the number of stored muons when the optimal wedge is included in the simulation.
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TUPMK016	Using Time Evolution of the Bunch Structure to Extract the Muon Momentum Distribution in the Fermilab Muon g-2 Experiment	experiment, positron, bunching, injection	1526
	W. Wu, B. Quinn UMiss, University, Mississippi, USA J.D. Crnkovic BNL, Upton, Long Island, New York, USA
	Beam dynamics plays an important role in achieving the unprecedented precision on measurement of the muon anomalous magnetic moment in the Fermilab Muon g-2 Experiment. It needs to find the muon momentum distribution in the storage ring in order to evaluate the electric field correction to muon anomalous precession frequency. We will show how to use time evolution of the beam bunch structure to extract the muon momentum distribution by applying a fast rotation analysis on the decay electron signals.
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WEXGBE1	Review of Top-up Injection Schemes for Electron Storage Rings	injection, kicker, synchrotron, septum	1745
	M. Aiba PSI, Villigen PSI, Switzerland
	Top-up operation, which nowadays is standard for lepton colliders and synchrotron light sources, has been developed over last decades. The accelerator performances have been drastically improved through top-up operation. However, future electron storage rings are designed, aiming at further high performance, to operate with strong nonlinear magnetic fields that may restrict their dynamic aperture. Consequently, the conventional off-axis injection and accumulation may become impossible. New injection schemes have been proposed and under development to overcome the difficulties and limitations expected in these machines. This paper reviews top-up injection schemes, including novel ideas recently proposed.
	Slides WEXGBE1 [3.584 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEXGBE1
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WEYGBF4	Development of a Solid-State Pulse Generator Driving Kicker Magnets for a Novel Injection System of a Low Emittance Storage Ring	kicker, injection, timing, high-voltage	1804
	T. Inagaki, H. Tanaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan H. Akikawa, K. Sato Nihon Koshuha Co. Ltd, Yokohama, Japan K. Fukami, C. Kondo, S. Takano Japan Synchrotron Radiation Research Institute (JASRI), RIKEN SPring-8 Center, Hyogo, Japan
	Funding: Funded by MEXT Japan A next generation electron storage ring represented by a diffraction-limited light source pursues an extremely low emittance leading to a small dynamic aperture and short beam lifetime. The top-up injection is hence indispensable to keep the stored beam current. The beam orbit fluctuation caused by the injection magnets should seriously obstruct utilization of an electron beam with sharp transverse profile. In order to solve these problems, a novel off-axis in-vacuum beam injection system was proposed. In the system, twin kicker magnets driven by a single solid-state pulsed power supply to launch a linear pi- bump orbit is the key to suppress the horizontal orbit fluctuation down to a level of several microns. Here, a big challenge is to achieve the magnetic field identity of the two kickers within an accuracy of 0.1%. This presentation overviews the proposed injection system and reports the development status focusing on the solid-state pulse generator.
	Slides WEYGBF4 [3.062 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEYGBF4
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WEPAF007	A Scheme for Asynchronous Operation of the APS-U Booster Synchrotron	booster, injection, extraction, timing	1823
	U. Wienands, T.G. Berenc, T. Fors, F. Lenkszus, N. Sereno, G.J. Waldschmidt ANL, Argonne, Illinois, USA
	Funding: Work supported by US DOE The APS-U 6-GeV MBA storage ring will have 42 pm beam emittance and relatively tight acceptance. This requires limiting the beam emittance out of the Booster synchrotron which is achieved by operating the Booster off-momentum, thus manipulating the damping partitions. However, the much higher charge for the APS-U strongly favors injecting on momentum into the Booster for maximum acceptance. An rf-frequency ramping scheme is proposed to allow injecting on momentum and then moving the beam off momentum. The ramp is adjusted from cycle to cycle to vary the total time taken by the beam from injection to extraction, thus aligning the Booster bunch with any chosen MBA storage ring bucket. The two rf systems will not be locked at any time of the cycle. The proposed scheme is compatible with the existing synchronization of the APS injector cycle to the 60-Hz line voltage which induces a variation in the start time of the acceleration cycle. The scheme removes the need to realign the Booster ring for total path length while optimizing its operation for high charge acceleration. A ferrite tuner is being considered for dynamic tuning of the rf cavities.
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WEPAF009	Optimising Response Matrix Measurements for LOCO Analysis	coupling, lattice, distributed, quadrupole	1826
	Y.E. Tan AS - ANSTO, Clayton, Australia
	The Linear Optics from Closed Orbit (LOCO) method is a common tool for determining storage ring lattice functions and requires a measured BPM to Corrector response matrix. For very large rings with many correctors, such measurements can be time consuming. The following study investigates how the number of correctors and the signal-to-noise ratio (SNR) affects the LOCO analysis results. For the Australian Synchrotron, the results show that four distributed correctors per plane with a SNR of >1000 is sufficient to fit the betatron functions to an accuracy of less than 0.2%.
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WEPAF010	Fast Glitch Detection of Coupled Bunch Instabilities and Orbit Motions	feedback, vacuum, injection, operation	1829
	W.X. Cheng, B. Bacha, K. Ha, Y. Li BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract No: DE-SC0012704 During high current operation at NSLS-II storage ring, vertical beam size spikes have been noticed. The spikes are believed due to ion instability associates with vacuum activities localized in the ring. A new tool has been developed using gated BPM turn-by-turn (TBT) data to detect beam centroid glitches. When one turn orbit deviates outside the predefined window, a global event will be generated. This allows synchronized data acquisition of TBT beam positions around the ring. Bunch by bunch data is acquired at the same time to analyze the possible coupled bunch instabilities (CBI). Besides CBI mainly due to ion bursts, fast orbit glitches have been captured with the new tool. Sources of the glitches can be identified.
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WEPAF011	Developments of Bunch by Bunch Feedback System at NSLS-II Storage Ring	feedback, operation, emittance, vacuum	1833
	W.X. Cheng, B. Bacha, Y. Li BNL, Upton, Long Island, New York, USA D. Teytelman Dimtel, San Jose, USA
	Funding: Work supported by DOE contract No: DE-SC0012704 Transverse bunch-by-bunch (BxB) feedback system has been constructed and in operation since the very beginning of NSLS-II storage ring commissioning. As the total beam current continues increasing in the past years, the system has been operating stable and reliable. Advanced BxB diagnostic functions have been developed using the system. Continuous tune measurement is realized with a diagnostic single bunch. Coupled bunch instability growth rate is able to be measured with the transient excitation. The BxB feedback system is also capable to excite a small fraction of total bunches for lattice measurement during high current operations. We present the most recent developments and operation experience on the BxB feedback system at NSLS-II.
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WEPAF012	Improvements of NSLS-II X-ray Diagnostic Beamlines	emittance, vacuum, photon, radiation	1837
	W.X. Cheng, B. Bacha, B.N. Kosciuk, D. Padrazo Jr BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract No: DE-SC0012704 There are two X-ray diagnostic beamlines (XDB) developed at NSLS-II storage ring to measure emittance, energy spread, and other machine parameters. The first beamline utilizes a soft bending magnet radiation has been in operation since 2014. The tungsten pinhole originally located in the air had corrosion issue. The beamline has been improved by extending the vacuum to the imaging system. The second X-ray pinhole beamline using three-pole wiggler (TPW) radiation has been constructed and commissioned recently. Energy spread is able to be precisely measured due to large dispersion at the source point. A gated camera is equipped with the new beamline to acquire profiles within one turn. Recent operation experience and beam measurements will be presented in this paper.
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WEPAF013	Database for the Management of NSLS-II Active Interlock System	database, interface, synchrotron, MMI	1841
	J. Choi, R.P. Fliller, K. Ha, Y. Tian BNL, Upton, Long Island, New York, USA
	Funding: DOE Contract No. DE-SC0012704 NSLS-II is operating the active interlock (AI) system to protect the machine components from the synchrotron radiation from the accidentally mis-steered electron beam. For the systematic management, a relational database is dedicated to the AI system and working as the data provider as well as the archiver. The paper shows how the database is structured and used for the AI system.
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WEPAF014	Commissioning the Superconducting Magnetic Inflector System for the Muon g-2 Experiment	experiment, injection, MMI, simulation	1844
	N.S. Froemming CENPA, Seattle, Washington, USA K.E. Badgley, H. Nguyen, D. Stratakis Fermilab, Batavia, Illinois, USA J.D. Crnkovic BNL, Upton, Long Island, New York, USA L.E. Kelton UKY, Kentucky, USA M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA
	The Fermilab muon g-2 experiment aims to measure the muon anomalous magnetic moment with a precision of 140 ppb - a fourfold improvement over the 540 ppb precision obtained in the BNL muon g-2 experiment. Both of these high-precision experiments require an extremely uniform magnetic field in the muon storage ring. A superconducting magnetic inflector system is used to inject beam into the storage ring as close as possible to the design orbit while minimizing disturbances to the storage-region magnetic field. The Fermilab experiment is currently in its first data-taking run, where the Fermilab inflector system is the refurbished BNL inflector system. This discussion reviews the Fermilab inflector system refurbishment and commissioning.
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WEPAF015	Commissioning the Muon g-2 Experiment Electrostatic Quadrupole System	quadrupole, experiment, positron, resonance	1848
	J.D. Crnkovic, V. Tishchenko BNL, Upton, Long Island, New York, USA K.E. Badgley, H. Nguyen, E. Ramberg Fermilab, Batavia, Illinois, USA E. Barlas Yucel, M. Yucel Istanbul Technical University, Maslak, Istanbul, Turkey J.M. Grange ANL, Argonne, Illinois, USA A.T. Herrod Cockcroft Institute, Warrington, Cheshire, United Kingdom A.T. Herrod The University of Liverpool, Liverpool, United Kingdom J.L. Holzbauer, W. Wu UMiss, University, Mississippi, USA H.D. Sanders APP, Freeville, New York, USA H.D. Sanders Sanders Pulsed Power LLC, Batavia, Illinois, USA N.H. Tran BUphy, Boston, Massachusetts, USA
	The Fermilab Muon g-2 experiment aims to measure the muon anomaly with a precision of 140 parts-per-billion (ppb) - a fourfold improvement over the 540 ppb precision obtained by the BNL Muon g-2 experiment. These high precision experiments both require a very uniform muon storage ring magnetic field that precludes the use of vertical-focusing magnetic quadrupoles. The Fermilab Electrostatic Quadrupole System (EQS) is the refurbished and upgraded BNL EQS, where this overview describes the Fermilab EQS and its recent operations.
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WEPAF016	Application of Quad-Scan Measurement Techniques to Muon Beams in the Muon g-2 Experiment	experiment, emittance, quadrupole, scattering	1852
	J. Bradley Edinburgh University, Edinburgh, United Kingdom J.D. Crnkovic BNL, Upton, Long Island, New York, USA B.E. Drendel, D. Stratakis Fermilab, Batavia, Illinois, USA N.S. Froemming CENPA, Seattle, Washington, USA
	Determination of the properties of a beam during transport is a vital process for most accelerator-related experiments; for example Fermilab's Muon g-2 experiment requires large numbers of muons to be stored in a storage ring of 7 meter radius, and the transmission fraction has been shown to depend strongly on the properties of the beam, specifically the Twiss parameters. The current equipment in the muon campus beamlines allows only measurement of beam profiles which limits how well propagation can be predicted, however by using the well-studied quad-scan technique it is possible to obtain all of the Twiss parameters at a point using these profiles. Experimental quad-scans of muon beams have not yet been reported, this paper introduces the quad-scan technique and then goes on to discuss the analysis of one such experiment and the results obtained, showing that such a technique is applicable in the muon g-2 experiment to obtain the Twiss parameters without requiring installation of new equipment.
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WEPAF041	Use of Dimension-Reduction Techniques With Multi-Objective Genetic Algorithms to Improve the Vertical Emittance and Orbit at CESR	emittance, simulation, lattice, electron	1901
	W.F. Bergan, I.V. Bazarov, C.J. Duncan, D. L. Rubin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA D. Liarte, J.P. Sethna Cornell University, Ithaca, New York, USA
	Funding: DOE DE-SC0013571 NSF DGE-1650441 In order to reduce the vertical emittance at the Cornell Electron Storage Ring (CESR), we first measure and correct the vertical orbit, dispersion, and coupling. However, due to the finite resolution of our optics measurements, we still retain a significant residual emittance. In order to correct this further, we made use of the theory of sloppy models, according to which certain high-dimensionality systems can be modeled with significantly fewer "eigenparameters" that still contain most of the effect on the desired objective, in this case, the emittance.* However, we noted that using these knobs for tuning often resulted in increased vertical orbit errors. In an attempt to constrain these, we have applied multi-objective genetic algorithms to this problem. We have found that it can be more efficient to run such algorithms using our eigenparameters as the genes to be varied, as opposed to the raw magnet values. When running with the first 8 such knobs as genes, we can get either orbits or beam sizes as good as we obtain with our regular emittance-tuning algorithm which uses all the corrector magnets. *K.S. Brown and J.P. Sethna, Phys. Rev. E 68, 021904 (2003).
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WEPAF042	Measurement of Beam yz Crabbing Tilt Due to Wake Fields Using Streak Camera at CESR	wakefield, positron, coupling, cavity	1905
	S. Wang, D. L. Rubin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This research was supported by NSF PHYS-1068662, PHYS-1416318 and DMR-1332208. Transverse vertical wake fields can increase the vertical emittance and distort the phase space of a bunch in a storage ring. Recently, we observed charge-dependent vertical beam size growth with a single scraper inserted through the top of the storage ring vacuum chamber. This apparent growth was due in large part to the yz coupling (vertical crabbing) induced by the wake field from the asymmetric scraper configuration. Here, we report a direct measurement of a small beam yz crabbing tilt using a streak camera. The recorded images (projected beam profiles in yz plane) are analyzed with three different methods, which yield consistent beam yz tilts. We found the directly-measured current-dependent beam tilts by the streak camera are consistent with the beam tilts calculated from a wake field model.
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WEPAK009	Applications of the Interferometric Beam Size Monitor at BESSY II	diagnostics, operation, electron, photon	2103
	M. Koopmans, P. Goslawski, J.G. Hwang, A. Jankowiak, M. Ries, A. Schälicke, G. Schiwietz HZB, Berlin, Germany
	For the upgrade project of the BESSY~II storage ring to BESSY~VSR * an interferometric beam size monitor was designed and set up. Since this system uses visible light it can be upgraded efficiently to provide bunch resolved measurements. These are required for machine commissioning, development and to ensure long term quality and stability of user operation of BESSY~VSR. Various applications of the system are outlined and measurements are presented. * A. Jankowiak et al., eds., BESSY VSR Technical Design Study, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany, June 2015. DOI: 10.5442/R0001
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WEPAK011	Development of the Electron-Beam Diagnostics for the Future BESSY-VSR Storage Ring	electron, diagnostics, laser, dipole	2110
	G. Schiwietz, J.G. Hwang, M. Koopmans, M. Ries, A. Schälicke HZB, Berlin, Germany
	This contribution focusses on the different types of new or improved electron-beam monitors at BESSY II for bunch resolved measurements under future BESSY-VSR conditions. A new diagnostics platform, involving three different dipole beam lines will be built for different di-pole-related optical and THz methods. Our main concepts for robust future monitors for bunch length, beam size and position are presented in the following.
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WEPAL005	Beam Size Measurement and PSF Evaluate of KB Mirror Monitor at SSRF	SRF, optics, electron, photon	2151
	D.C. Zhu, J.S. Cao, Y.F. Sui, J.H. Yue IHEP, Beijing, People's Republic of China
	Funding: Work supported by National Nature Science Foundation of China(11605213) A Kirkpatrick Baez mirror imaging system was designed and installed to measure the transverse beam size and emittance of SSRF storage ring. Two crossed cylindrical mirrors are used to image the dipole source point in the horizontal and vertical direction. Both mirrors could be moved in and out in order to interchangeable with an original X-ray pinhole system. Hard X-ray with peak energy of 20.5 keV was focused at the X-ray scintillator camera. Aberration and point spread function which would cause image blur were evaluated. System commissioning and optimization have been done. PSF measurement was acquired using beam based calibration scheme by varying the beam images with different quadrupole settings and fitting them with the corresponding theoretical beam sizes.
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WEPAL026	High Repetition Rate, Single-Shot Electro-Optical Monitoring of Longitudinal Electron Bunch Dynamics Using the Linear Array Detector KALYPSO	electron, laser, radiation, FEL	2216
	G. Niehues, E. Blomley, M. Brosi, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, L. Rota, M. Schuh, P. Schönfeldt, M. Weber KIT, Eggenstein-Leopoldshafen, Germany N. Hiller PSI, Villigen PSI, Switzerland
	Funding: This work is funded by the BMBF contract numbers: 05K13VKA and 05K16VKA. High repetition rate diagnostics are required when detecting single-shot electro-optical (EO) bunch profiles. The KIT storage ring KARA (KArlsruhe Research Accelerator) is the first storage ring in the world that has a near-field EO bunch-profile monitor in operation. By imprinting longitudinal electron bunch profiles onto chirped laser pulses, single-shot detection is feasible. However, limitations of available detection systems are challenging: The constraints are either given by the repetition rate or the duration of the consecutive acquisitions. Two strategies can overcome these limitations: Based on the photonic time-stretch method, the ps laser pulses can be stretched to the ns range using km long fibers. The readout with a high-bandwidth oscilloscope then enables a single-shot detection at high repetition rates. The other strategy is the development of dedicated ultra-fast photodetector arrays allowing direct detection of the ps pulses at MHz repetition rates. We developed KALYPSO, a linear detector array with a DAQ allowing to record high data-rates over long time scales. Here, we present recent results of studies of the longitudinal electron bunch dynamics using KALYPSO.
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WEPAL027	Filling Pattern Measurements Using Dead-Time Corrected Single Photon Counting	photon, synchrotron, radiation, data-analysis	2219
	B. Kehrer, E. Blomley, M. Brosi, E. Bründermann, A.-S. Müller, M. Schuh, P. Schönfeldt, J.L. Steinmann KIT, Karlsruhe, Germany
	Time-correlated single photon counting (TCSPC) is a versatile tool for various accelerator diagnostics aspects. Amongst others it allows a precise determination of the filling pattern. At the visible light diagnostics port at the Karlsruhe Research Accelerator (KARA), the KIT storage ring, a Single-Photon Avalanche Diode (SPAD) in combination with a histogramming device (PicoHarp) is used. To compensate for possible dead-time effects, a correction scheme was developed and tested successfully. The compensation increases the dynamic range in which accurate measurements are possible and avoids distortion of the measured filling pattern. This contribution presents the experimental setup, as well as a series of benchmark measurements.
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WEPAL028	Study of the Influence of the CSR Impedance on the Synchronous Phase Shift at KARA	impedance, synchrotron, simulation, radiation	2223
	P. Schönfeldt, E. Blomley, M. Brosi, E. Bründermann, J. Gethmann, B. Kehrer, A.-S. Müller, A.I. Papash, J.L. Steinmann KIT, Karlsruhe, Germany
	Funding: This work has been supported by the German Federal Ministry of Education and Research (Grant No. 05K16VKA) and the Helmholtz Association (Contract No. VH-NG-320). Measurements of the bunch current dependent synchronous phase shift are a standard method to characterize the impedance of a storage ring. To study this shift, different experimental approaches can be used. In this contribution, we first derive the phase shift caused by the impedance describing the emission of coherent synchrotron radiation (CSR) based on numerical simulations of the longitudinal phase space. The predicted shift is compared to measurement results obtained by time-correlated single photon counting.
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WEPAL047	Online Optimisation of the MAX IV 3 GeV Ring Dynamic Aperture	dynamic-aperture, sextupole, octupole, optics	2281
	D.K. Olsson MAX IV Laboratory, Lund University, Lund, Sweden
	In order to improve the resilience of the MAX IV 3 GeV ring's beam to a horizontal dipole kick while at the design tunes (42.20, 16.28) the optimisation algorithm RCDS (Robust Conjugate Direction Search) was deployed. The algorithm was able to increase the horizontal acceptance by finding new settings for the sextupole and octupole magnets, whilst leaving the vertical acceptance virtually unchanged. Additionally, the optimisation increased the momentum acceptance of the lattice, increasing beam lifetime.
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WEPAL055	TPS Beam Trip Analysis and Dose Distribution	radiation, kicker, SRF, neutron	2302
	B.Y. Chen, F.Y. Chang, S. Fann, C.S. Huang, C.H. Kuo, T.Y. Lee, C.C. Liang, W.Y. Lin, Y.C. Lin, Y.-C. Liu NSRRC, Hsinchu, Taiwan
	Failure analysis during TPS users operation is im-portant to improve the performance of the TPS storage ring. In this report, we discuss the particular radiation dose patterns, relevant to different beam trips, and the development of a tool to help us analyse this dose distri-bution. We will use this analysing tool to train our ability for future failure analysis to shorten the time it takes to find the problem.
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WEPAL057	Methods to Detect Error Sources and Their Application at the TPS	photon, kicker, cavity, injection	2305
	C.H. Huang, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.Y. Wu NSRRC, Hsinchu, Taiwan
	For a low-emittance photon light source, beam stability is a very important property to attain a high-quality photon beam. While it is hard to avoid beam perturbations in a storage ring, it is more important to quickly find the source locations and to remove or eliminate the sources as soon as possible. In this report, we develop a method to identify the locations of multiple sources. For a source with a particular frequency, the relative phase between sources can also be obtained. This method has been a useful tool during TPS operation and its methodology and practical applications are described in this report.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL057
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WEPMF008	Preliminary Designs and Test Results of Bipolar Power Supplies for APS Upgrade Storage Ring	power-supply, hardware, controls, operation	2381
	J. Wang, I.A. Abid, R.T. Keane, G.S. Sprau 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. The upgrade (APS-U) of the APS storage ring requires more than 1200 bipolar power supplies. Based on the performance requirement, the power supplies can be divided into two categories: fast bipolar power supplies for fast correctors and slow bipolar power supplies for trim coils and slow correctors. The common requirement of the power supplies is a bipolar output current up to ±15 A. The main difference is that the fast corrector power supplies require a small-signal bandwidth of 10 kHz. A prototype DC/DC power converter utilizing a MOSFET H-bridge circuit with a 500 kHz PWM was successfully developed through the R&D program, achieving the required bandwidth with less than 3-dB attenuation for a signal 0.5% of ±15 A. After the successful R&D program, the preliminary designs were performed to further improve the performance and to finalize the schematics, the PCB layouts, and the power supply constructions. The two types of the power supplies share the majority of the designs and features, with minor differences for the different bandwidth requirement. This paper presents the preliminary design, the key power supply functions and features, and the test results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF008
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WEPMF011	Design and Status of Sirius Light Source RF Systems	cavity, booster, LLRF, lattice	2391
	R.H.A. Farias, A.P.B. Lima, L. Liu, F.S. Oliveira LNLS, Campinas, Brazil
	Sirius is the new synchrotron light source currently under construction at the site of the Brazilian Synchro-tron Light Laboratory (LNLS) in Campinas, Brazil. The facility comprises a 3 GeV electron storage ring, a full energy booster and a 150 MeV linac. This work provides a brief description of the RF system of the booster and storage ring, presenting their main characteristics and specification goals.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF011
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WEPMF019	Conceptual Design of the eRHIC Storage Ring Magnets	dipole, sextupole, quadrupole, simulation	2407
	H. Witte, J.S. Berg, S. Tepikian 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. Presently the electron-ion collider eRHIC is under design, which aims to provide a facility with a peak luminosity of 10³⁴cm^-2sec^-1. Part of the eRHIC accelerator is the addition of an electron storage ring to the existing tunnel. This paper describes the magnets required for this storage ring. The necessary bending is provided by a triplet of dipole magnets, which generate excess bending to create additional radiation damping to allow a larger beam-beam tune shift. Each triplet consists of two long, low field magnets and a short, high-field magnet. This paper also describes the quadrupole and sextupole magnets necessary for this machine. All magnets require a large aperture to accommodate the beam-pipe.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF019
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WEPMF020	Pulsed Systems for eRHIC Beam Injection and Extraction	injection, kicker, extraction, electron	2410
	W. Zhang, M. Blaskiewicz, A. Hershcovitch, C.J. Liaw, H. Lovelace III, M. Mapes, G.T. McIntyre, J.-L. Mi, C. Montag, C. Pai, V. Ptitsyn, J. Sandberg, N. Tsoupas, J.E. Tuozzolo, G.M. Wang, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu 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. The electron-ion collider eRHIC requires a variety of kickers and septa for injection and extraction of beams throughout the entire collider complex. We plan to use pulsed systems for beam injection and extraction in Electron RCS, Electron Storage Ring, and Hadron ring. In this paper, we describe the pulsed systems required for beam transfer in the eRHIC Ring-Ring Pre-conceptual Design. We will outline the parameter ranges, technology choices, and opportunities for research and development in pulsed power technology.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF020
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WEPMF021	Magnet Design Considerations for an Ultralow Emittance Canadian Light Source	quadrupole, lattice, emittance, FEL	2413
	L.O. Dallin, D. Bertwistle CLS, Saskatoon, Saskatchewan, Canada
	The strong focusing requirements for ultralow emittance light sources result in high field magnets that are very close together. High fields are readily achieved by using small magnet gaps. This is possible due to the small beam sizes involved. Reduction in the physical aperture and the reduction in the good field region requirements results in magnets with compact transverse dimensions. The very strong focusing of the magnets results in very small drift spaces between the various magnetic elements. To keep these drift spaces clear magnets with recessed coils have been studied. In such magnets the coils do not stick out beyond the end of the magnet yoke in the longitudinal direction. By placing the coils on the outer yoke loss of efficiency can be avoided while maintaining good control of the higher order field harmonics. This is very well suited for quadrupole magnets where only two coils are required. Possible designs for gradient dipoles and sexutpoles are also considered.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF021
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WEPMF072	Magnet Power Supplies for ALS-U	power-supply, magnet-design, dipole, sextupole	2538
	G.C. Pappas, J.-Y. Jung, C.A. Swenson LBNL, Berkeley, California, USA
	The ALS-U project is an upgrade to the existing Advanced Light Source at Lawrence Berkeley Laboratory to a diffraction limited light source. To be able to achieve the small horizontal emittance of the ALS-U, the three bend achromats in the ALS will be replaced with nine bend achromats. Because the lifetime of the ALS-U beam will be significantly reduced, the plan is to use a swap out injection scheme between the storage ring and a new accumulator ring. The present plan is to use individual power supplies for each magnet in the storage ring, and series connected magnet strings for the accumulator ring. The sheer number of supplies needed, along with the tighter stability requirements for the ALS-U, is demanding in terms of the power supply requirements for stability and reliability. This paper will discuss the ALS-U magnet power supply requirements, and possible options to meet them.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF072
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WEPML028	NEG Coated Vacuum Chambers and Bake-Out-Concept for the HESR at FAIR	dipole, quadrupole, vacuum, heavy-ion	2745
	H. Jagdfeld, N.B. Bongers, J. Böker, P. Chaumet, F.M. Esser, F. Jordan, F. Klehr, G. Langenberg, D. Prasuhn, L. Semke, R. Tölle FZJ, Jülich, Germany A. Mauel, G. Natour, U. Pabst Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics, Jülich, Germany
	The High-Energy Storage Ring (HESR) is part of the international Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt. Forschungszentrum Jülich (IKP and ZEA-1) is responsible for the design and installation of the HESR. The HESR is designed for antiprotons and heavy ion experiments as well. Therefore the vacuum is required to be 10^-11 mbar or better. To achieve this extreme high vacuum (XHV), NEG coated chambers will be used in combination with common vacuum pumps to reach the needed pumping speed and capacity everywhere in the accelerator ring. For activation of the NEG material a bake-out system will be developed and installed. A bake-out test bench was used for checking the achievable end pressure and developing the bake-out system for the NEG coated chambers of the HESR. The results of the tests and the bake-out concept including the layout of the control system are presented. In addition, the temperature distribution of the dedicated heater jackets inside the dipole and quadrupole magnets are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML028
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WEPML047	Study on RF Coupler Kicks of SRF Cavities in the BESSY VSR Module	cavity, SRF, HOM, GUI	2804
	A.V. Tsakanian, T. Mertens Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany H.-W. Glock, J. Knobloch, M. Ries, A.V. Vélez HZB, Berlin, Germany
	The BESSY VSR upgrade of the BESSY II light source represents a novel approach to simultaneously store long (ca. 15ps) and short (ca. 1.7ps) bunches in the storage ring with the standard user optics. This challenging goal requires installation of four new SRF multi-cell cavities (2x1.5GHz and 2x1.75GHz) equipped with strong waveguide HOM dampers ensuring tolerable beam coupling impedance, necessary for stable operation. These cavities will operate at high 20MV/m in CW mode and at the zero-crossing phase according to the accelerating voltage. Consequently the transverse voltages will be maximum and can impact the transverse beam dynamics. The asymmetric character of those transverse kicks are caused by cavity fundamental power couplers (FPC) with strong monopole terms, introducing transverse kick to on-axis particles. Different FPC orientations were analyzed to optimize the net coupler kick from the four cavity chain. The coupler kick strength of each cavity is estimated taking into account accelerating mode amplitudes and phases required for operation in VSR mode.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML047
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THXGBD4	Sirius Light Source Status Report	kicker, injection, booster, MMI	2886
	A.R.D. Rodrigues, F.C. Arroyo, O.R. Bagnato, J.F. Citadini, R.H.A. Farias, J.G.R.S. Franco, R. Junqueira Leao, L. Liu, S.R. Marques, R.T. Neuenschwander, C. Rodrigues, F. Rodrigues, R.M. Seraphim, O.H.V. Silva LNLS, Campinas, Brazil
	Sirius is a Synchrotron Light Source Facility based on a 4th generation 3 GeV low emittance electron storage ring that is under construction in Campinas, Brazil. Presently the main tunnel for the accelerators is ready to start installations. The Linac tunnel was delivered earlier and the 150 MeV Linac from SINAP is almost ready to start commissioning early May. Commissioning of the storage ring is expected to start by the end of this year (2018). In this paper we briefly review the overall project parameters and design concepts and focus on highlights from the main subsystems.
	Slides THXGBD4 [28.400 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THXGBD4
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THYGBF3	Challenges of FAIR Phase 0	operation, controls, MMI, experiment	2947
	M. Bai, A. Adonin, S. Appel, R. Bär, M.C. Bellachioma, U. Blell, C. Dimopoulou, G. Franchetti, O. Geithner, P. Gerhard, L. Groening, F. Herfurth, R. Hess, R. Hollinger, H.C. Hüther, H. Klingbeil, A. Krämer, S.A. Litvinov, F. Maimone, D. Ondreka, N. Pyka, S. Reimann, A. Reiter, M. Sapinski, B. Schlitt, G. Schreiber, M. Schwickert, D. Severin, R. Singh, P.J. Spiller, J. Stadlmann, M. Steck, R.J. Steinhagen, K. Tinschert, M. Vossberg, G. Walter, U. Weinrich GSI, Darmstadt, Germany
	After two-year's shutdown, the GSI accelerators plus the latest addition of storage ring CRYRING, will be back into operation in 2018 as the FAIR phase 0 with the goal to fulfill the needs of scientific community and the FAIR accelerators and detector development. Even though GSI has been well known for its operation of a variety of ion beams ranging from proton up to uranium for multi research areas such as nuclear physics, astrophysics, biophysics, material science, the upcoming beam time faces a number of challenges in re-commissioning its existing circular accelerators with brand new control system and upgrade of beam instrumentations, as well as in rising failures of dated components and systems. The cycling synchrotron SIS18 has been undergoing a set of upgrade measures for fulfilling future FAIR operation, among which many measures will also be commissioned during the upcoming beam time. This paper presents the highlights of the challenges such as re-establishing the high intensity heavy ion operation as well as parallel operation mode for serving multi users. The status of preparation including commissioning results will also be reported.
	Slides THYGBF3 [2.948 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBF3
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THPAF014	Studies of the Single-Bunch Instabilities in the Booster of HEPS	booster, impedance, lattice, injection	2971
	H.S. Xu, Z. Duan, J.L. Li, Y.M. Peng, S.K. Tian, N. Wang IHEP, Beijing, People's Republic of China
	High Energy Photon Source (HEPS), which is proposed in China, is an ultra-low emittance storage ring based synchrotron light source. Because of the requirement of the relatively high single-bunch charge, the booster may suffer from the single-bunch instabilities. A preliminary impedance model has been developed for the studies of collective instabilities in the booster. Based on this impedance model, the longitudinal and transverse single-bunch instabilities have been studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF014
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THPAF030	PETRA III Storage Ring Performance Improvement Based on Multi-Objective Genetic Algorithms (MOGA)	injection, operation, multipole, dynamic-aperture	3018
	X.N. Gavaldà, J. Keil, G.K. Sahoo, R. Wanzenberg DESY, Hamburg, Germany
	The performance of the 3th generation light sources relies on the beam lifetime and the injection efficiency, both related with the beam dynamic properties of the storage ring as momentum acceptance and dynamic aperture, respectively. High values of beam lifetime and injection efficiency are desirable to reduce the storage ring instabilities during injection, the radiation losses and the energy consumption of the facility. This paper reports the first application of Multi-Objective Genetic Algorithms (MOGA) to optimize the linear and non-linear beam dynamics of PETRA III storage ring. Genetic algorithms are a heuristic search that mimics the process of natural evolution to optimize problems with a high level of complexity, as in the case of PETRA III storage ring composed by hundreds of magnets. This computational method uses hundreds of CPUs. MOGA is used to maximize the dynamic aperture and the momentum acceptance finding new combinations of quadrupole and sextupole settings in a multi-dimensional parameter space maintaining the solutions in the level of ten picometers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF030
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THPAF046	Optics Measurements in Storage Rings Based on Simultaneous 3-Dimensional Beam Excitation	optics, dipole, synchrotron, betatron	3068
	L. Malina, J.M. Coello de Portugal CERN, Geneva, Switzerland J.M. Coello de Portugal UPC, Barcelona, Spain
	Optics measurements in storage rings usually employ excitation in both transverse directions. This needs to be repeated at several different beam energies and is time-consuming. In this paper, we develop a new optics measurement technique, which excites the beam in all three spatial dimensions simultaneously. It allows measuring the linear optics and chromatic properties at the same time, leading to speed up of the optics measurements. The measurement method has been successfully demonstrated in the LHC using AC-dipoles and RF frequency modulation. Analysis methods have been derived for the 3-dimensional beam excitation case. We quantify the resolution of the measured optical quantities. The first results suggest that the added complexity does not deteriorate the resolution of the linear optics measurement. In the future, this method can serve as an operational tool to check the optics or even to correct it.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF046
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THPAF085	Estimation of Dielectric Losses in the Bessy VSR Warm Beam Pipe Absorbers	cavity, HOM, GUI, wakefield	3185
	T. Flisgen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany H.-W. Glock HZB, Berlin, Germany A.V. Tsakanian Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany
	Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association. Currently Helmholtz Zentrum Berlin prepares the update of the BESSY II ring to BESSY VSR. The updated ring will be capable to simultaneously store short and long bunches to satisfy the various user demands. For this sake, a cryomodule accommodating two 1.5 GHz and two 1.75 GHz superconducting cavities will be installed into the storage ring. The cavity string will be equipped with warm dielectric absorber rings at both ends. Together with the waveguide dampers of the cavities, these rings damp electromagnetic fields excited by the beam. This contribution presents the estimation of the dielectric losses in the beam pipe absorber rings of the BESSY VSR module. The presented approach is based on determining a broad band impedance of the dielectric ring by exciting the numerical model with a single broad band Gaussian bunch. Subsequently, the power deposited into the ring is estimated in frequency domain by multiplying the impedance with the square of the beam current for all considered harmonics of the beam. Finally, these power contributions are added up. In addition to details of the scheme, the contribution presents results for the recent absorber layout of the BESSY VSR string.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF085
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THPAF086	Beam Dynamics Simulations for Operating a Robinson Wiggler at the MLS	wiggler, optics, operation, dynamic-aperture	3189
	J. Li, J. Feikes, M. Ries HZB, Berlin, Germany T. Tydecks CERN, Geneva, Switzerland
	A Robinson wiggler is planned to be installed in the storage ring of the Metrology Light Source (the MLS). The Robison wiggler (RW) is a device consisting of a chain of combined-function magnets (CFMs), intended to manipulate the damping partition numbers and thus adjust the longitudinal emittance. The objective is to lengthen the bunch in order to improve the Touschek lifetime. However, the nonlinear perturbation of the beam dynamics due to the Robinson wiggler could limit the achievable improvement. Therefore, a symplectic method of modeling the wiggler has been established to study these nonlinear effects. Optimized solutions have been developed for both the ramping procedure and the future daily operation of the wiggler and are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF086
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THPAK031	Suppression of Longitudinal Coupled Bunch Instability by Harmonic Cavity in UVSOR Electron Storage Ring	damping, synchrotron, HOM, cavity	3280
	A. Mochihashi KIT, Eggenstein-Leopoldshafen, Germany M. Fujimoto, K. Hayashi, M. Katoh UVSOR, Okazaki, Japan J. H. Hasegawa, M. Hosaka, M. Hosaka, Y. Takashima, Y. Takashima Nagoya University, Nagoya, Japan M. Hosaka, Y. Takashima Aichi Synchrotron Radiation Center, Aichi, Japan M. Katoh Sokendai - Okazaki, Okazaki, Aichi, Japan
	In the UVSOR electron storage ring, which is dedicated for a VUV synchrotron radiation light source, a longitudinal coupled bunch instability (LCBI) is observed in multi-bunch operation. To suppress the LCBI, we routinely operate a third harmonic cavity (HCV) in a passive mode. By properly tuning HCV, the instability is almost completely suppressed. Because of the lower beam energy (750 MeV) and brilliant beam emittance (17.5 nm-rad), the Touschek effect becomes severe in the UVSOR. To guarantee enough beam lifetime, we also apply HCV for lengthening the bunch. The suppression of the instability and increasing the beam lifetime are crucial benefits by HCV for the UVSOR. However, not only the origin of the LCBI but also the Landau damping effect by HCV has not been understood systematically yet. We have noticed that one of the HOMs at HCV itself could cause the LCBI and observed the behavior of the instability, which strongly depends on the beam current. From the experiment we have discussed the cause of the instability with the HOM theory. We have also tried to observe synchrotron tune spread and discussed a competition between the Landau damping and the instability growth. Present affiliation of the first auther : Karlsruhe Institute of Technology
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK031
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THPAK032	Elaborated Modeling of Synchrotron Motion in Vlasov-Fokker-Planck Solvers	simulation, synchrotron, electron, damping	3283
	P. Schönfeldt, T. Boltz, A. Mochihashi, A.-S. Müller, J.L. Steinmann KIT, Karlsruhe, Germany
	Funding: Funded by the German Federal Ministry of Education and Research (Grant No. 05K16VKA) & Initiative and Networking Fund of the Helmholtz Association (contract number: VH-NG-320). Solving the Vlasov-Fokker-Planck equation is a well-tested approach to simulate dynamics of electron bunches self-interacting with their own wake-field. Typical implementations model the dynamics of a charge density in a damped harmonic oscillator, with a small perturbation due to collective effects. This description imposes some limits to the applicability: Because after a certain simulation time coherent synchrotron motion will be damped down, effectively only the incoherent motion is described. Furthermore - even though computed - the tune spread is typically masked by the use of a charge density instead of individual particles. As a consequence, some effects are not reproduced. In this contribution, we present methods that allow to consider single-particle motion, coherent synchrotron oscillation, non-linearities of the accelerating voltage, higher orders of the momentum compaction factor, as well as modulations of the accelerating voltage. We also provide exemplary studies - based on the KIT storage ring KARA (KArlsruhe Research Accelerator) - to show the potential of the methods.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK032
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THPAK053	Side Effects of Local Bump in TPS Storage Ring	sextupole, quadrupole, radiation, dipole	3340
	M.-S. Chiu, C.H. Chen, J.Y. Chen, P.J. Chou, F.H. Tseng NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is a low-emittance 3-GeV light source at National Synchrotron Radiation Research Center. Five in-vacuum undulator beamlines were delivered to users on Sep. 22, 2016. Another 2 EPU beamlines will be open to user in near future. In the beginning, the local bump was used to do ID spectrum optimization since 2016. After this procedure, the ID spectrum are consistent between theoretical simulation and measurement. Recently, we found the local bump will cause tune shift and orbit distortion. In this paper, we will present the effect of local bump in TPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK053
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THPAK055	Suppression of Transverse Beam Instabilities by Stripline Kickers at TPS	kicker, impedance, feedback, damping	3346
	P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng, F.H. Tseng NSRRC, Hsinchu, Taiwan
	Collective beam instabilities could limit the accelerator performance if proper countermeasures are not in place. Active beam feedback systems are commonly used to suppress beam instabilities. The resistive wall impedance including phase-II insertion devices at TPS are calculated with analytical formulas. The growth rate of transverse coupled bunch instabilities due to wall impedance is estimated by theory. The RF properties of existing stripline kickers in TPS are analyzed with a 3-D electromagnetic simulation code GdfidL. Based on the above analysis, the requirements for a beam feedback system are calculated and the results are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK055
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THPAK088	Matrix Representation of Lie Transform in TensorFlow	network, simulation, GPU, linear-dynamics	3438
	A.N. Ivanov, S.N. Andrianov, N.V. Kulabukhova, A.A. Sholokhova St. Petersburg State University, St. Petersburg, Russia E. Krushinevskii, E. Sboeva Saint Petersburg State University, Saint Petersburg, Russia
	In the article, we propose an implementation of the matrix representation of Lie transform using TensorFlow as a computational engine. TensorFlow allows easy description of deep neural networks and provides automatic code execution on both single CPU/GPU and cluster architectures. In this research, we demonstrate the connection of the matrix Lie transform with polynomial neural networks. The architecture of the neural network is described and realized in code. In terms of beam dynamics, the proposed technique provides a tool for both simulation and analysis of experimental results using modern machine learning techniques. As a simulation technique one operates with a nonlinear map up to the necessary order of nonlinearity. On the other hand, one can utilize TensorFlow engine to run map optimization and system identification problems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK088
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THPAK113	Cavity Characterization Studies With the Latest Revision of YACS	cavity, coupling, superconducting-cavity, higher-order-mode	3503
	B.D. Isbarn, S. Koetter, B. Riemann, M. Sommer, T. Weis DELTA, Dortmund, Germany
	Funding: Work supported by the BMBF under contract no. 05K13PEB. YACS is a 2.5D finite element method solver capable of solving for the full 3D eigenfrequency spectra of resonant axisymmetric structures while reducing the computational problem to a 2D rotation plane. The most recent revision of YACS now supports arbitrary order basis functions for the geometry and field discretization. In earlier revisions of YACS spurious modes were introduced by increasing the order of either the geometry or field basis functions. To prevent the emergence of spurious modes, YACS now matches the function spaces of the in-plane and out-plane function basis, and thus yields spurious free solutions. To demonstrate the capabilities of YACS, extensive cavity characterization studies on curved multicell microwave cavities are presented. Due to the combined utilization of the rotation symmetry, higher order basis functions and curved elements, eigenfrequency spectra above 10 GHz for L-band multicell structures can be easily obtained.
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THPAK114	Evaluation of an Interior Point Method Specialized in Solving Constrained Convex Optimization Problems for Orbit Correction at the Electron Storage Ring at DELTA	software, feedback, electron, closed-orbit	3507
	S. Koetter, A. Glaßl, B.D. Isbarn, D. Rohde, M. Sommer, T. Weis DELTA, Dortmund, Germany
	The slow orbit feedback at the electron storage ring at DELTA will be upgraded with new software. Finding a set of dipole-field-strength variations which minimize the deviation of the orbit from a reference orbit requires solving a convex optimization problem subject to inequality constraints. This work focuses on exploiting properties of a special type of interior point methods, which can solve this problem, for orbit correction at DELTA. After comparing runtimes of an interior point method to a Newton-like optimization algorithm, the performance of the new slow-orbit-feedback software is assessed based on measurement results.
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THPAK139	Lost Muon Studies for the Muon g-2 Experiment at Fermilab	positron, experiment, background, resonance	3573
	S. Ganguly, K. T. Pitts University of Illinois at Urbana-Champaign, Urbana, USA J.D. Crnkovic BNL, Upton, Long Island, New York, USA C. C. Polly Fermilab, Batavia, Illinois, USA
	The Fermilab Muon g-2 experiment aims to measure the muon anomalous magnetic moment aμ with an unprecedented precision of 140 parts per billion (ppb), a four-fold improvement over the 540~ppb precision obtained by the BNL Muon g-2 Experiment. This study presents preliminary work on estimating the muon losses by using double coincidences in the calorimeters.
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THPAK144	A Pseudospectral Method for Solving the Bloch Equations of the Polarization Density in e^- Storage Rings	polarization, electron, ion-effects, synchrotron	3589
	K.A. Heinemann, O. Beznosov, J.A. Ellison UNM, Albuquerque, New Mexico, USA D. Appelö University of Colorado at Boulder, Boulder, USA D.P. Barber DESY, Hamburg, Germany
	Funding: Work supported by DOE under DE-SC0018008 We consider the numerical evolution of Bloch equations for the polarization density in high-energy electron storage rings. Equilibrium polarization is well characterized by the DK formulas for current rings, but deviations may be important at the high energies we have in mind. We believe the Bloch equations derived in* give a more accurate description at all energies. These form a system of three coupled linear partial differential equations for the three components of the polarization density. Following** we formulate the equations in action-angle variables and approximate the Fokker-Planck terms. We aim to integrate these equations numerically in order to approximate the equilibrium and compare with the DK formulas. The smoothness and simple geometry of the problem makes it amenable to pseudospectral discretization using Fourier modes in the angles and Chebyshev polynomials in the actions, leading to a large ODE system. We will explore time stepping algorithms for the needed long time integration. Here, we present results for simple models checking the accuracy of the numerical method but note that our ultimate goal is to simulate polarization in the FCC and CEPC rings. * Ya.S.Derbenev, A.M.Kondratenko, Sov. Phys. Dokl., 19, p.438 (1975). ** D.P.Barber, K.Heinemann, H.Mais, G.Ripken, A Fokker-Planck treatment of stochastic particle motion…, DESY-91-146, 1991.
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THPAK147	Super-Period Multi-Bend Achromat Lattice with Interleaved Dispersion Bumps for the HALS Storage Ring	lattice, sextupole, emittance, controls	3597
	Z.H. Bai, L. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	We have proposed a multi-bend achromat (MBA) lattice concept, called the MBA with interleaved dispersion bumps, in which two pairs of interleaved dispersion bumps are created in each lattice cell. Due to that many nonlinear effects can be effectively cancelled out within one cell and also many knobs can be used for nonlinear optimization, this MBA concept has given both large dynamic aperture (DA) and large dynamic momentum aperture in the lattice design of the Hefei Advanced Light Source (HALS). In this paper, to further enlarge DA, we extend the concept to the case of a super-period lattice consisting of two cells. In the super-period lattice, there are 1.5 pairs of bumps in each cell. A super-period 7BA lattice is preliminarily designed for the HALS, and a larger DA is obtained.
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THPAK148	Preliminary Study of a Nine-Bend Achromat Lattice for a Diffraction-Limited Storage Ring	lattice, emittance, sextupole, synchrotron	3600
	P.H. Yang, Z.H. Bai, L. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	In recent years, multi-bend achromat (MBA) lattices have been widely used for the design of diffraction-limited storage rings (DLSRs) being developed around the world as the next-generation storage ring synchrotron sources. To better solve the problem of very serious non-linear dynamics in the DLSR lattice design, recently we proposed a new MBA lattice concept called the MBA lattice with interleaved dispersion bumps , which was then applied to designing 7BA lattices for the Hefei Ad-vanced Light Source (HALS), with the result showing rather good nonlinear dynamics performance. In this paper, a 9BA lattice also following our MBA concept is preliminarily designed as a possible option for the HALS with a natural emittance of less than 30 pm·rad. Since generally the 9BA lattice can have a much lower emit-tance than the usually used 7BA lattice, the work in the paper will provide an inspiration for the existing third-generation synchrotron sources to upgrade to DLSRs with much lower emittances. Zhenghe Bai et al., MOPH13, Proc. SAP2017, Jishou, China, 2017.
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THPAK153	Linac Optics Correction With Trajectory Scan Data	quadrupole, linac, optics, lattice	3606
	X. Huang, Y.-C. Chao, T.J. Maxwell SLAC, Menlo Park, California, USA T. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	We proposed and tested a scheme to measure and correct linac optics by scanning the beam trajectory in the horizontal and vertical phase spaces. The trajectory data are compared to tracking data in a fitting scheme, from which we can derive the quadrupole strength errors. Simulation is carried out to evaluate the requirements and the performance of the method. The method is experimentally applied to FEL linacs.
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THPAL013	First Serial Magnetic Measurements of the NICA Collider Twin-Aperture Dipoles	collider, dipole, booster, superconducting-magnet	3645
	M.M. Shandov, V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin JINR, Dubna, Russia I.I. Donguzov, M. A. Kashunin, V. A. Mykhailenko, T.A. Parfylo, A.V. Shemchuk, D.A. Zolotykh JINR/VBLHEP, Dubna, Moscow region, Russia
	NICA is a new accelerator complex under construction at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, to study properties of hot and dense baryonic matter. Magnetic system of the NICA collider includes 80 twin-aperture dipole and 86 quadrupole superconducting magnets. The collider twin-aperture magnet is 1.94 m long, 120 mm/70 mm (h/v) aperture with window-frame design similar to the Nuclotron magnet. The measurement of the magnetic field parameters is supported to be conducted for both apertures of each collider magnet. This paper describes magnetic measurements methods and the development of the dedicated system for serial dipole magnets of the NICA collider.
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THPAL028	Commissioning of the Bunch-by-Bunch Feedback System in the MAX IV 1.5 GeV Ring	feedback, cavity, kicker, synchrotron	3688
	D. Olsson, Å. Andersson, F.J. Cullinan, P.F. Tavares MAX IV Laboratory, Lund University, Lund, Sweden
	The MAX IV 1.5 GeV ring is an electron storage ring for production of synchrotron light in the IR to soft X-ray spectral range. The ring will deliver light to its first users during 2018. Bunch-By-Bunch (BBB) feedback has been needed to suppress coupled-bunch mode instabilities (CBMIs), and the feedback has this far been provided in all three planes by a single stripline kicker. This is done by combining the horizontal and vertical baseband feedback signals with the longitudinal feedback signal that is upconverted to the 150 MHz - 250 MHz range. The combined signal is then fed to two stripline electrodes. The layout of the BBB feedback system in the MAX IV 1.5 GeV ring is presented in this paper. Results from instability studies are also discussed.
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THPAL046	Energy-Savings for the TPS Booster RF System at the NSRRC in Taiwan	controls, booster, timing, injection	3748
	F.-T. Chung, F.Y. Chang, L.-H. Chang, M.H. Chang, S.W. Chang, L.J. Chen, Y.T. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	In this paper, we discuss an energy-savings control sys-tem for the Taiwan Photon Source (TPS) booster RF sys-tem. During top-up storage ring operation, a timing con-trol is activated to reduce the booster RF transmitter en-ergy consumption when no injection is required. When-ever injection into the TPS storage ring is needed, the booster RF transmitter is immediately adjusted to operat-ing conditions. This timing-control system will save an energy of 380, 000 kWh annually.
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THPAL050	Beam Dynamics of the First Beams for the IFMIF-EVEDA RFQ Commissioning	operation, controls, synchrotron, site	3754
	C.S. Chen, W.S. Chan, Y.Y. Cheng, Y.-C. Chung, C.Y. Liu, Y.-H. Liu, Z.-D. Tsai NSRRC, Hsinchu, Taiwan
	Since December 31th 2014, the first synchrotron light from Taiwan Photon Source (TPS) was stored in the storage ring, the challenge to operate both Taiwan Light Source (TLS) and TPS smoothly and reliably became a significant issue for all members in NSRRC. On the one hand, the beam quality of former TLS must not been impaired due to the occupied resources by TPS, on the other hand, the most efforts were devoted to achieving steady operation of TPS. In order to operate both ring stably, some mutual backup structures were designed in the compressed air system and the chilled water system between TLS and TPS. The primary advantage of these mutual backup systems is minimizing the risk of beam-trip while any one of the utility system fails. Secondly, the mutual backup structures provide more flexible usage to accomplish energy conservation. From both risk-reduction and energy conservation points of view, the backup systems will do a great deal of good in the future.
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THPAL056	Vibration Measurements in the TPS Vacuum System	vacuum, radiation, synchrotron, synchrotron-radiation	3772
	Y.C. Yang, C.K. Chan, C.-C. Chang, C.S. Chen, J. -Y. Chuang, Y.M. Hsiao, C.C. Liang, Y.Z. Lin NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is currently operated in top-up mode for users. In order to improve the stability of the synchrotron light source, vibrations related to the vacuum system have been investigated and improved by turning off pumping systems and reducing the flow rate in chamber cooling water circuits. In this paper, vibrations in different vacuum chambers with normal cooling water condition were investigated, their sources were recorded and clarified and properties of different materials for water tubes were also compared.
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THPAL057	Development of the Aluminum Beam Duct for the Ultra-Low Emittance Light Source	vacuum, experiment, impedance, emittance	3775
	G.-Y. Hsiung, J.-R. Chen, C.M. Cheng, S-N. Hsu, H.P. Hsueh, Y.C. Yang NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	The future light source with ultra-low emittance, typically < 500 pm rad, requests the beam duct with inner aperture < 20 mm for the electron storage ring. Besides, the cross section of the beam duct must be kept smooth for lowering the impedance. The aluminum extruded beam duct of 10 mm inside and 1 ~ 2 m in length was developed for this purpose. The beam duct was machined in ethanol to obtain a clean surface for a lower thermal outgassing rate. To mitigate the impedance of the flange connection, a special designed diamond-edge gasket and the aluminum flange without knife edge were developed. The inner diameters of both flange and gasket, 10 mm, are the same as that of beam duct. The sealing of the gasket has been proved leak-tight. The ultimate pressure and the thermal outgassing rate of the beam duct has achieved < 2.0·10^-10 Torr and < 1.4·10^-13 Torr l/(s cm²), respectively after baking. Those results fulfill both the ultrahigh vacuum and lowest impedance are applicable for the next generation ultra-low emittance light source.

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MOPMF014

Polarization at eRHIC Electron Storage Ring, an Ergodic Approach

polarization, electron, simulation, lattice

112

F. Méot
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.
Based on considerations of ergodicity of the dynamical system of an electron bunch at equilibrium, the preservation of polarization in an electron storage ring is estimated from the tracking of a very limited number of electrons. This has a substantial impact on required High Power Computing resources, in noticeable contrast with the method generally used that tracks tens of electron bunches, each comprised of thousands of particles, for several thousands of turns. It is also shown that a minimum number of tracking turns is required in order to ensure the numerical convergence of the linear regressions that yield depolarizing time constant values from tracking, in both methods.

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MOPMF028

A Superconvergent Algorithm for Invariant Spin Field Stroboscopic Calculations

simulation, resonance, polarization, lattice

145

D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: National Science Foundation and the Department of Energy
Stroboscopic averaging can be used to calculate the invariant spin field \bfn for particles with a finite oscillation amplitude in phase space. The standard technique starts with making a guess for \bfn(\bfr), which is a function of the phase space position \bfr. By tracking a particle's orbital position forward in time and then projecting the guessed \bfn backwards to the starting phase space point, the average of the backward projected spins will converge to the invariant spin direction linearly as 1/N where N is the number of turns tracked. The convergence can be accelerated by an iterative method that uses an approximate invariant spin field constructed by averaging the calculated spin field over points that are close in orbital phase space. This superconvergent algorithm has been built into a new program based upon the Bmad toolkit for charged particle and X-ray simulations.

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MOPMF071

Polarization Studies for the eRHIC electron Storage Ring

polarization, electron, coupling, solenoid

292

E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA
S. Tepikian
BNL, Upton, Long Island, New York, USA

Funding: Manuscript authored by Fermi Res. All., LLC under Contr. No. DE-AC02-07CH11359 and Brookhaven Sc. Ass., LLC under Contr. No. DE-AC02-98CH10886 with the U.S. DOE, Office of Science, Office of HEP.
A hadron/lepton collider with polarized beams has been under consideration by the scientific community since some years, in the U.S. and Europe. Among the various proposals, those by JLAB and BNL with polarized electron and proton beams are currently under closer study in the U.S. Experimenters call for the simultaneous storage of electron bunches with both spin helicity. In the BNL based Ring-Ring design, electrons are stored at top energy in a ring to be accommodated in the existing RHIC tunnel. The transversely polarized electron beam is injected into the storage ring at variable energies, between 5 and 18 GeV. Polarization is brought into the longitudinal direction at the IP by a couple of spin rotators. In this paper results of first studies of the attainable beam polarization level and lifetime in the storage ring at 18 GeV are presented.

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TUYGBD3

eRHIC Design Status

electron, hadron, luminosity, proton

628

V. Ptitsyn, G. Bassi, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, A. Blednykh, J.M. Brennan, S.J. Brooks, K.A. Brown, K.A. Drees, A.V. Fedotov, W. Fischer, D.M. Gassner, W. Guo, Y. Hao, A. Hershcovitch, H. Huang, W.A. Jackson, J. Kewisch, C. Liu, H. Lovelace III, Y. Luo, F. Méot, M.G. Minty, C. Montag, R.B. Palmer, B. Parker, S. Peggs, V.H. Ranjbar, G. Robert-Demolaize, S. Seletskiy, V.V. Smaluk, K.S. Smith, S. Tepikian, P. Thieberger, D. Trbojevic, N. Tsoupas, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman, W. Zhang
BNL, Upton, Long Island, New York, USA
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The electron-ion collider eRHIC aims at a luminosity around 10³⁴cm^-2sec^-1, using strong cooling of the hadron beam. Since the required cooling techniques are not yet readily available, an initial version with a peak luminosity of 3*10³³cm^-2sec^-1 is being developed that can later be outfitted with strong hadron cooling. We will report on the current design status and the envisioned path towards 10³⁴cm^-2sec^-1 luminosity.

Slides TUYGBD3 [11.790 MB]

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TUPAF078

Recent Results of HESR Original Stochastic Cooling Tanks at COSY

kicker, pick-up, experiment, hardware

913

R. Stassen, B. Breitkreutz, N. Shurkhno
FZJ, Jülich, Germany

The High Energy Storage Ring (HESR) of the FAIR project at GSI Darmstadt will be very important for different scientific programs due to the modularized start version of FAIR. Stochastic cooling together with barrier bucket operation will be the key component to fulfill the requirements of the different experiments. First pickup and first kicker of the HESR stochastic cooling system have been installed into the COSY accelerator at FZJ Jülich. COSY is well suited to test the performance of the HESR stochastic cooling hardware at different energies and variable particle numbers. The novel dedicated HESR-structures were already successfully tested at the Nuclotron in Dubna for longitudinal cooling and during a beam time 2017 for transverse cooling at COSY. The results of the last stochastic cooling beam time will be presented as well as the first use of GaN based amplifiers in a stochastic cooling system. The HESR needs fast transmission-lines between PU and KI. Beside air-filled coax-lines, optical hollow fiber-lines are very attractive. First results with such a hollow fiber used for the transverse signal path will be presented.

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TUPAL028

New Feature of the Oscillating Synchrotron Motion Derived from the Hamiltonian Composed of Three Motions

synchrotron, betatron, closed-orbit, experiment

1060

K. Jimbo
Kyoto University, Kyoto, Japan

The equation for the synchrotron motion was derived from the Hamiltonian, which was composed of coasting, betatron and synchrotron motions*. The betatron oscillation is　the horizontal oscillation. The synchrotron oscillation is not only an oscillation of the revolution frequency but also an oscillation of the average radius. The synchrotron oscillation is both longitudinal and horizontal oscillations and it is possible to exchange energy with the betatron oscillation. The synchrotron oscillation occurs under a constant particle velocity and the Hamiltonian is conserved.
*K.Jimbo, Physical Review Special Topics - Accelerator and Beams 19, 010102 (2016).

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TUPMF008

Design, Construction, and Magnetic Field Measurements of a Helical Superconducting Undulator for the Advanced Photon Source

undulator, photon, electron, experiment

1263

M. Kasa, S.J. Bettenhausen, J.D. Fuerst, E. Gluskin, Q.B. Hasse, Y. Ivanyushenkov, I. Kesgin, Y. Shiroyanagi, E. Trakhtenberg
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
A helical superconducting undulator (HSCU) was developed and installed at the Advanced Photon Source (APS). Implementation of a unique design of the helical coil former allowed for a compact turn around scheme of the conductor at the ends of the device during winding. Inherent to the coil winding design was the gradual reduction of the magnitude of the magnetic field at the ends of the device. The coil former design along with the magnetic measurement results will be described.

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TUPMF012

Determination of the Ground Motion Orbit Amplification Factors Dependence on the Frequency for the APS Upgrade Storage Ring

ground-motion, factory, lattice, simulation

1272

V. Sajaev, C.A. Preissner
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.
The Advanced Photon Source (APS) is pursuing an upgrade to the storage ring that will provide electron beam with extremely low emittance. To allow users to take advantage of this small beam size, the beam orbit motion has to be kept stable to within a fraction of the beam size, which translates to sub-micron orbit stability requirement. Ground motion provides significant contribution to the overall expected beam motion, especially at lower frequencies where the ground motion has larger amplitudes. At the same time, the lattice amplification factors reduce when the ground motion becomes coherent at low frequencies. In this paper, we will present simulation of the lattice amplification factor dependence on the ground motion coherence length and show results of the ground motion coherence measurements at APS. After that, we will determine the lattice amplification factors dependence on the ground motion frequency, that can be used to calculate the expected effect of the ground motion on the orbit stability.

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TUPMF013

Optimizations of Nonlinear Beam Dynamics Performance on APS-U Lattice

lattice, MMI, sextupole, multipole

1276

Y.P. Sun, M. Borland
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.
For next-generation storage ring light sources, such as the Advanced Photon Source (APS) Multi-Bend Achromat (MBA) upgrade, the strong nonlinearities introduced by the strong chromaticity sextupoles plus the small physical apertures make it challenging to achieve large dynamic acceptance (DA) and long Touschek lifetime, even when using the on-axis swap-out injection scheme. Several different methods have been explored for nonlinear dynamics optimization. The optimization objectives variously include the chromaticities up to third order, resonance driving and detuning terms, on- and off-momentum dynamic acceptance, chromatic and geometric tune footprint, local momentum acceptance (LMA), variation of betatron oscillation invariant, Touschek lifetime, etc. In addition, optimization can be performed without errors, with selected random errors, and with sets of errors that reflect post-commissioning conditions. In this paper, these different optimization methods are compared for the nonlinear beam dynamics performance of the Advanced Photon Source upgrade (APS-U) lattice, in terms of the dynamic acceptance, local momentum acceptance, and other performance measures. The impact from different error sources is also studied.

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TUPMF018

Simulation Studies of the Helical Superconducting Undulator Installed at APS

multipole, simulation, undulator, operation

1290

A. Xiao, V. Sajaev, Y.P. Sun
ANL, Argonne, Illinois, USA

A multi-year project at APS has resulted in construction of a helical superconducting undulator (HSCU) for installation in the ring. Before installation, simulation studies were done to ensure that APS performance will not be compromised. This paper describes the method used for calculating the HSCU's perturbation effects and the simulation results for both calculated and measured field map.
Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

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TUPMF022

Electron Beam Scanning in the Delta-Type Undulators for Sirius

undulator, electron, radiation, polarization

1300

A. B. da Cruz, L. Liu
LNLS, Campinas, Brazil

We report on simulation studies to analyze the possibility of scanning the electron beam, and not scanning the sample, in CDI experiments using a Delta-Type undulator in the 3GeV Sirius electron storage ring presently under construction at LNLS. This would allow much faster scans in diffraction limited storage rings such as Sirius. We study displaced beam trajectories through the undulators and analyze the effects on the emitted radiation. It is possible to show that displacements on the order of ± 500 micrometers around the center will introduce variations in the radiation spectrum that are less that 1 per cent and thus acceptable for Coherent Diffraction Imaging experiments.

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TUPMF036

Top Off of NSLS-II with Inefficient Injector

booster, injection, linac, operation

1327

R.P. Fliller, A.A. Derbenev, V.V. Smaluk, X. Yang
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The NSLS-II is a 3 GeV storage with a full energy injector capable of top off injection. The injector consists of a 200 MeV linac injecting a 3 GeV booster. Recent operational events have caused us to investigate 100 MeV injection into the booster. As the booster was not designed for injection at this low energy, beam loss is observed with this low energy booster injection. This beam loss not only results of overall charge loss from the train, but a change in the overall charge distribution in the bunch train. In this paper we discuss the performance of injecting into the storage ring with the inefficient charge transfer through the injector. The changes to the top off method are discussed, as well as the achieved storage ring current stability and fill pattern.

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TUPMF046

The Injection and Extraction Design of the Booster for the HEPS Project

injection, extraction, kicker, booster

1356

Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu
IHEP, Beijing, People's Republic of China

The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.

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TUPMF049

Evolution of the Lattice Design for the High Energy Photon Source

lattice, emittance, injection, photon

1363

G. Xu, S.Y. Chen, Y. Jiao, J.L. Li, Y.M. Peng, Q. Qin, J.Q. Wang, C.H. Yu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is a high-energy, ultralow-emittance, kilometer-scale storage ring light source to be built in China. The HEPS lattice design has been started since 2008. In this paper we will review the evolution of the HEPS lattice design over the past ten years, focusing mainly on the linear optics design and nonlinear optimization.

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TUPMF050

DA Optimization Experiences in the Heps Lattice Design

lattice, sextupole, emittance, photon

1367

Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China

In the past decade, the so-called diffraction-limited storage ring (DLSR) light sources were proposed, promising much better radiation performance than available in the existing third generation light sources. Regarding the very strong focusing and chromatic sextupoles that required for reaching an ultralow emittance, to optimize the nonlinear dynamics and achieve an adequate dynamic aperture is an important topic in a DLSR design. In this paper we will present some tips distilled from the DA optimization experience of the High Energy Photon Source over the past ten years, hoping it could provide some aids to other ultralow-emittance designs.

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TUPMF052

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

lattice, booster, injection, emittance

1375

G. Xu, X. Cui, Z. Duan, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, 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 ultralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physical design and studies on HEPS over the past one year, covering issues of storage lattice design and optimization, booster design, injection design, collective effects, error study, insertion device effects, beam lifetime, etc.

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TUPMF054

Performance Comparison of Different Ultralow Emittance Unit Cells

emittance, lattice, dipole, quadrupole

1382

Y. Jiao, X.Y. Li, G. Xu
IHEP, Beijing, People's Republic of China

The available minimum emittance of a storage ring and the ring performance is closely related to the unit cell of the lattice. Up to now, several ultralow-emittance unit cells have been proposed and applied in the lattice design of the diffraction-limited storage ring light sources. In this study we quantitatively compared the performance of three typical unit cells, based on mainly the parameters of the High Energy Photon Source. The results indicate that the modified-TME unit cell with antibend and longitudinal gradient dipole allows the lowest possible emittance, given a long enough cell length.

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TUPMF058

Conceptual Design of HEPS Injector

booster, injection, linac, dipole

1394

J.L. Li, H. Dong, Z. Duan, Y.Y. Guo, D.Y. He, Y. Jiao, W. Kang, C. Meng, S. Pei, Y.M. Peng, J.R. Zhang, P. Zhang, Z.S. Zhou
IHEP, Beijing, People's Republic of China

Abstract The High Energy Photon Source (HEPS) will be constructed in the following few years. The light source is comprised of an ultra-low emittance storage ring and a full energy injector. The energy of the storage ring is 6 GeV. The injector is comprised of a 500 MeV linac, a 500 MeV to 6 GeV booster synchrotron and transport lines connecting the machines. In the present design, the linac uses normal conducting S-band bunching and accelerating structures. The booster adopts FODO cells, has a circumference of about 454 m and an emittance lower than 40 nmrad. The injector can provide a single-bunch charge up to 2 nC at 6 GeV for the storage ring. This paper briefly introduces the conceptual design of the injector of the HEPS.

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TUPMF062

Status of HEPS Booster Lattice Design and Physics Studies

booster, injection, lattice, extraction

1407

Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, C. Meng, S.K. Tian, H.S. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) with an ul-tralow emittance is proposed to be built in Beijing, Chi-na. It will utilize a booster as its full energy injector. On-axis swap-out injection is chosen as the baseline injec-tion scheme for the storage ring. As required by the stor-age ring, a beam with a bunch charge up to 2.5 nC is needed to be injected in the booster. However, limited by the transverse mode coupling instability (TMCI), such a high bunch charge is challenging. To overcome this problem, a lattice with a considerable large momentum compaction factor is designed. This paper reports the lattice design and physics studies of the HEPS booster, including injection and extraction design, error studies, eddy current effects, collective effects, and so on.

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TUPMF063

The Considerations of Improving TMCI Threshhold on HEPS Booster

booster, lattice, linac, injection

1411

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

The High Energy Photon Source (HEPS) is proposed in Beijing, China. The on-axis swap-out injection scheme will be used in the storage ring mainly because of the small dynamic aperture. Therefore, the booster needs to store more than 2.5 nC bunch charge. Under this requirement, the transverse mode coupling instability (TMCI) at the injection energy becomes the bunch charge restriction in the booster. Several changes in booster and linac for improving bunch charge threshold limited by TMCI are considered. The details will be expressed in this paper.

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TUPMF069

Low Gain FEL Oscillator Option for PETRA IV

FEL, undulator, emittance, electron

1420

I.V. Agapov
DESY, Hamburg, Germany
Y.-C. Chae
ANL, Argonne, Illinois, USA
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Next generation synchrotron storage rings will have electron beam density approaching that necessary for driving an XFEL. It falls short of the quality required for the high-gain x-ray regime above 1 keV, mainly due to the large energy spread and small peak current, bit is sufficient to reach low-gain regime. Here we explore the parameter space of a low gain XFEL oscillator, to establish the feasibility range of such a device for the Petra upgrade project.

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TUPMK001

Removal of RF-Fingers at the Edges of the Injection Kickers

impedance, resonance, kicker, injection

1485

T.F.G. Günzel, N. Ayala, F.F.B. Fernández, U. Iriso, M. Pont
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The ALBA storage ring injection kickers are equipped with RF-fingers to close a 2.5 mm gap between the ceramic tube and the metallic flange. After two distortion incidents that required the replacement of the fingers, their removal was decided. The decision could be supported by the observation that most of the additional impedance is created above the cut-off frequency of the beam pipe. This was later confirmed by a temperature decrease in that zone after the removal. Furthermore it was checked that the thresholds of the longitudinal coupled bunch instabilities of modes trapped around the resulting open gap are above the maximal applied beam current of 400 mA.

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TUPMK003

Advances in the Sirius Delta-Type Undulator Project

undulator, lattice, polarization, MMI

1491

L.N.P. Vilela, R. Basílio, J.F. Citadini, J.R. Furaer, F. Rodrigues
LNLS, Campinas, Brazil

The Delta undulator is a compact adjustable-phase insertion device that provides full light polarization control. Five undulators of this type will be installed in the initial operation phase of Sirius, the new 4th generation synchrotron light source that is being built by the Brazilian Synchrotron Light Laboratory (LNLS). In this work we present the recent advances in the development of Sirius Delta-type undulator, the studies of the effects of this device in the storage ring beam dynamics and assembly and measurements strategies.

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TUPMK004

Using Decoherence to Prevent Damage to the Swap-Out Dump for the APS Upgrade

simulation, emittance, kicker, electron

1494

M. Borland, J.C. Dooling, R.R. Lindberg, V. Sajaev, A. Xiao
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.
The Advanced Photon Source (APS) is pursuing an upgrade of the storage ring to a hybrid seven-bend-achromat* design, which will operate in swap-out mode. The ultra-low emittance (about 30 pm in both planes) combined with the desire to provide high charge (15 nC) in individual bunches, entails very high energy density in the beam. Simple estimates, confirmed by simulation, indicate that interaction of such a bunch with the dump material will result in localized melting. Over time, it is possible that the beam would drill through the dump and vent the ring vacuum. This would seem to prevent extraction and dumping of bunches as part of swap out, and also suggests that transferring of bunches out of the ring carries significant risk. We devised an idea for using a pre-kicker to cause decoherence of the target bunch emittances, making it safe to extract. Simulations show that the concept works very well.
*L. Farvacque et al., IPAC13, 79 (2013).

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TUPMK010

Differences in Current Dependent Tune Shifts Measured by Direct or ORM Based Methods

vacuum, impedance, optics, wakefield

1510

Y.E. Tan, R.T. Dowd
AS - ANSTO, Clayton, Australia

The change in the tunes as a function of total beam current is a well documented effect and has been attributed to quadrupole like self induced wakefields. Theoretical models presented by others have utilised direct methods (spectrum analyser) to measure the tunes in the analysis. In this report we shall present observations that show the ORM method, Linear Optics from Closed Optics (LOCO), and direct methods have significantly different tune gradients. The different tune gradients is attributed to the static (ORM) and dynamic (direct) nature of the measurements where in the static case the vacuum chamber is to be considered as a thin wall while in the dynamic case the vacuum chamber wall is to be considered as a thick wall.

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TUPMK014

Dipole Fringe Field Analysis of the NSLS-II Storage Ring

dipole, optics, lattice, simulation

1519

J. Choi, Y. Hidaka, T.V. Shaftan, C.J. Spataro, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: DOE Contract No. DE-SC0012704
In the NSLS-II storage ring, the effect of the dipole fringe field is not negligible and was considered already at the design phase. Especially in the vertical direction, the standard simulation codes are using the parameter called FINT (fringe Field INTegral) and, if there is no specific information, it is usually set to 0.5 which is considered as the reasonable average. With the hall-probe measurement data of the NSLS-II storage ring dipoles, we evaluated measured FINTs and applied them to the beam simulation. The paper shows the resulting FINTs and their effects.

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TUPMK015

Initial Studies into Longitudinal Ionization Cooling for the Muon g-2 Experiment

emittance, simulation, experiment, target

1522

J. Bradley
Edinburgh University, Edinburgh, United Kingdom
J.D. Crnkovic
BNL, Upton, Long Island, New York, USA
D. Stratakis, M.J. Syphers
Fermilab, Batavia, Illinois, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

Fermilab's Muon g-2 experiment aims to measure the anomalous magnetic moment of the muon to an unprecedented precision of 140 ppb. It relies on large numbers of muons surviving many turns in the storage ring without colliding with the sides, at least long enough for the muons to decay. Longitudinal ionization cooling is introduced with respect to Fermilab's Muon g-2 experiment in an attempt to increase storage and through this the statistics and quality of results. The ionization cooling is introduced to the beam through a material wedge, an initial simulation study is made into the positioning, material, and geometrical parameters of this wedge using G4Beamline. Results suggest a significant increase of 20 - 30% in the number of stored muons when the optimal wedge is included in the simulation.

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TUPMK016

Using Time Evolution of the Bunch Structure to Extract the Muon Momentum Distribution in the Fermilab Muon g-2 Experiment

experiment, positron, bunching, injection

1526

W. Wu, B. Quinn
UMiss, University, Mississippi, USA
J.D. Crnkovic
BNL, Upton, Long Island, New York, USA

Beam dynamics plays an important role in achieving the unprecedented precision on measurement of the muon anomalous magnetic moment in the Fermilab Muon g-2 Experiment. It needs to find the muon momentum distribution in the storage ring in order to evaluate the electric field correction to muon anomalous precession frequency. We will show how to use time evolution of the beam bunch structure to extract the muon momentum distribution by applying a fast rotation analysis on the decay electron signals.

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WEXGBE1

Review of Top-up Injection Schemes for Electron Storage Rings

injection, kicker, synchrotron, septum

1745

M. Aiba
PSI, Villigen PSI, Switzerland

Top-up operation, which nowadays is standard for lepton colliders and synchrotron light sources, has been developed over last decades. The accelerator performances have been drastically improved through top-up operation. However, future electron storage rings are designed, aiming at further high performance, to operate with strong nonlinear magnetic fields that may restrict their dynamic aperture. Consequently, the conventional off-axis injection and accumulation may become impossible. New injection schemes have been proposed and under development to overcome the difficulties and limitations expected in these machines. This paper reviews top-up injection schemes, including novel ideas recently proposed.

Slides WEXGBE1 [3.584 MB]

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WEYGBF4

Development of a Solid-State Pulse Generator Driving Kicker Magnets for a Novel Injection System of a Low Emittance Storage Ring

kicker, injection, timing, high-voltage

1804

T. Inagaki, H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
H. Akikawa, K. Sato
Nihon Koshuha Co. Ltd, Yokohama, Japan
K. Fukami, C. Kondo, S. Takano
Japan Synchrotron Radiation Research Institute (JASRI), RIKEN SPring-8 Center, Hyogo, Japan

Funding: Funded by MEXT Japan
A next generation electron storage ring represented by a diffraction-limited light source pursues an extremely low emittance leading to a small dynamic aperture and short beam lifetime. The top-up injection is hence indispensable to keep the stored beam current. The beam orbit fluctuation caused by the injection magnets should seriously obstruct utilization of an electron beam with sharp transverse profile. In order to solve these problems, a novel off-axis in-vacuum beam injection system was proposed. In the system, twin kicker magnets driven by a single solid-state pulsed power supply to launch a linear pi- bump orbit is the key to suppress the horizontal orbit fluctuation down to a level of several microns. Here, a big challenge is to achieve the magnetic field identity of the two kickers within an accuracy of 0.1%. This presentation overviews the proposed injection system and reports the development status focusing on the solid-state pulse generator.

Slides WEYGBF4 [3.062 MB]

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WEPAF007

A Scheme for Asynchronous Operation of the APS-U Booster Synchrotron

booster, injection, extraction, timing

1823

U. Wienands, T.G. Berenc, T. Fors, F. Lenkszus, N. Sereno, G.J. Waldschmidt
ANL, Argonne, Illinois, USA

Funding: Work supported by US DOE
The APS-U 6-GeV MBA storage ring will have 42 pm beam emittance and relatively tight acceptance. This requires limiting the beam emittance out of the Booster synchrotron which is achieved by operating the Booster off-momentum, thus manipulating the damping partitions. However, the much higher charge for the APS-U strongly favors injecting on momentum into the Booster for maximum acceptance. An rf-frequency ramping scheme is proposed to allow injecting on momentum and then moving the beam off momentum. The ramp is adjusted from cycle to cycle to vary the total time taken by the beam from injection to extraction, thus aligning the Booster bunch with any chosen MBA storage ring bucket. The two rf systems will not be locked at any time of the cycle. The proposed scheme is compatible with the existing synchronization of the APS injector cycle to the 60-Hz line voltage which induces a variation in the start time of the acceleration cycle. The scheme removes the need to realign the Booster ring for total path length while optimizing its operation for high charge acceleration. A ferrite tuner is being considered for dynamic tuning of the rf cavities.

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WEPAF009

Optimising Response Matrix Measurements for LOCO Analysis

coupling, lattice, distributed, quadrupole

1826

Y.E. Tan
AS - ANSTO, Clayton, Australia

The Linear Optics from Closed Orbit (LOCO) method is a common tool for determining storage ring lattice functions and requires a measured BPM to Corrector response matrix. For very large rings with many correctors, such measurements can be time consuming. The following study investigates how the number of correctors and the signal-to-noise ratio (SNR) affects the LOCO analysis results. For the Australian Synchrotron, the results show that four distributed correctors per plane with a SNR of >1000 is sufficient to fit the betatron functions to an accuracy of less than 0.2%.

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WEPAF010

Fast Glitch Detection of Coupled Bunch Instabilities and Orbit Motions

feedback, vacuum, injection, operation

1829

W.X. Cheng, B. Bacha, K. Ha, Y. Li
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract No: DE-SC0012704
During high current operation at NSLS-II storage ring, vertical beam size spikes have been noticed. The spikes are believed due to ion instability associates with vacuum activities localized in the ring. A new tool has been developed using gated BPM turn-by-turn (TBT) data to detect beam centroid glitches. When one turn orbit deviates outside the predefined window, a global event will be generated. This allows synchronized data acquisition of TBT beam positions around the ring. Bunch by bunch data is acquired at the same time to analyze the possible coupled bunch instabilities (CBI). Besides CBI mainly due to ion bursts, fast orbit glitches have been captured with the new tool. Sources of the glitches can be identified.

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WEPAF011

Developments of Bunch by Bunch Feedback System at NSLS-II Storage Ring

feedback, operation, emittance, vacuum

1833

W.X. Cheng, B. Bacha, Y. Li
BNL, Upton, Long Island, New York, USA
D. Teytelman
Dimtel, San Jose, USA

Funding: Work supported by DOE contract No: DE-SC0012704
Transverse bunch-by-bunch (BxB) feedback system has been constructed and in operation since the very beginning of NSLS-II storage ring commissioning. As the total beam current continues increasing in the past years, the system has been operating stable and reliable. Advanced BxB diagnostic functions have been developed using the system. Continuous tune measurement is realized with a diagnostic single bunch. Coupled bunch instability growth rate is able to be measured with the transient excitation. The BxB feedback system is also capable to excite a small fraction of total bunches for lattice measurement during high current operations. We present the most recent developments and operation experience on the BxB feedback system at NSLS-II.

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WEPAF012

Improvements of NSLS-II X-ray Diagnostic Beamlines

emittance, vacuum, photon, radiation

1837

W.X. Cheng, B. Bacha, B.N. Kosciuk, D. Padrazo Jr
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract No: DE-SC0012704
There are two X-ray diagnostic beamlines (XDB) developed at NSLS-II storage ring to measure emittance, energy spread, and other machine parameters. The first beamline utilizes a soft bending magnet radiation has been in operation since 2014. The tungsten pinhole originally located in the air had corrosion issue. The beamline has been improved by extending the vacuum to the imaging system. The second X-ray pinhole beamline using three-pole wiggler (TPW) radiation has been constructed and commissioned recently. Energy spread is able to be precisely measured due to large dispersion at the source point. A gated camera is equipped with the new beamline to acquire profiles within one turn. Recent operation experience and beam measurements will be presented in this paper.

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WEPAF013

Database for the Management of NSLS-II Active Interlock System

database, interface, synchrotron, MMI

1841

J. Choi, R.P. Fliller, K. Ha, Y. Tian
BNL, Upton, Long Island, New York, USA

Funding: DOE Contract No. DE-SC0012704
NSLS-II is operating the active interlock (AI) system to protect the machine components from the synchrotron radiation from the accidentally mis-steered electron beam. For the systematic management, a relational database is dedicated to the AI system and working as the data provider as well as the archiver. The paper shows how the database is structured and used for the AI system.

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WEPAF014

Commissioning the Superconducting Magnetic Inflector System for the Muon g-2 Experiment

experiment, injection, MMI, simulation

1844

N.S. Froemming
CENPA, Seattle, Washington, USA
K.E. Badgley, H. Nguyen, D. Stratakis
Fermilab, Batavia, Illinois, USA
J.D. Crnkovic
BNL, Upton, Long Island, New York, USA
L.E. Kelton
UKY, Kentucky, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

The Fermilab muon g-2 experiment aims to measure the muon anomalous magnetic moment with a precision of 140 ppb - a fourfold improvement over the 540 ppb precision obtained in the BNL muon g-2 experiment. Both of these high-precision experiments require an extremely uniform magnetic field in the muon storage ring. A superconducting magnetic inflector system is used to inject beam into the storage ring as close as possible to the design orbit while minimizing disturbances to the storage-region magnetic field. The Fermilab experiment is currently in its first data-taking run, where the Fermilab inflector system is the refurbished BNL inflector system. This discussion reviews the Fermilab inflector system refurbishment and commissioning.

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WEPAF015

Commissioning the Muon g-2 Experiment Electrostatic Quadrupole System

quadrupole, experiment, positron, resonance

1848

J.D. Crnkovic, V. Tishchenko
BNL, Upton, Long Island, New York, USA
K.E. Badgley, H. Nguyen, E. Ramberg
Fermilab, Batavia, Illinois, USA
E. Barlas Yucel, M. Yucel
Istanbul Technical University, Maslak, Istanbul, Turkey
J.M. Grange
ANL, Argonne, Illinois, USA
A.T. Herrod
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.T. Herrod
The University of Liverpool, Liverpool, United Kingdom
J.L. Holzbauer, W. Wu
UMiss, University, Mississippi, USA
H.D. Sanders
APP, Freeville, New York, USA
H.D. Sanders
Sanders Pulsed Power LLC, Batavia, Illinois, USA
N.H. Tran
BUphy, Boston, Massachusetts, USA

The Fermilab Muon g-2 experiment aims to measure the muon anomaly with a precision of 140 parts-per-billion (ppb) - a fourfold improvement over the 540 ppb precision obtained by the BNL Muon g-2 experiment. These high precision experiments both require a very uniform muon storage ring magnetic field that precludes the use of vertical-focusing magnetic quadrupoles. The Fermilab Electrostatic Quadrupole System (EQS) is the refurbished and upgraded BNL EQS, where this overview describes the Fermilab EQS and its recent operations.

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WEPAF016

Application of Quad-Scan Measurement Techniques to Muon Beams in the Muon g-2 Experiment

experiment, emittance, quadrupole, scattering

1852

J. Bradley
Edinburgh University, Edinburgh, United Kingdom
J.D. Crnkovic
BNL, Upton, Long Island, New York, USA
B.E. Drendel, D. Stratakis
Fermilab, Batavia, Illinois, USA
N.S. Froemming
CENPA, Seattle, Washington, USA

Determination of the properties of a beam during transport is a vital process for most accelerator-related experiments; for example Fermilab's Muon g-2 experiment requires large numbers of muons to be stored in a storage ring of 7 meter radius, and the transmission fraction has been shown to depend strongly on the properties of the beam, specifically the Twiss parameters. The current equipment in the muon campus beamlines allows only measurement of beam profiles which limits how well propagation can be predicted, however by using the well-studied quad-scan technique it is possible to obtain all of the Twiss parameters at a point using these profiles. Experimental quad-scans of muon beams have not yet been reported, this paper introduces the quad-scan technique and then goes on to discuss the analysis of one such experiment and the results obtained, showing that such a technique is applicable in the muon g-2 experiment to obtain the Twiss parameters without requiring installation of new equipment.

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WEPAF041

Use of Dimension-Reduction Techniques With Multi-Objective Genetic Algorithms to Improve the Vertical Emittance and Orbit at CESR

emittance, simulation, lattice, electron

1901

W.F. Bergan, I.V. Bazarov, C.J. Duncan, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
D. Liarte, J.P. Sethna
Cornell University, Ithaca, New York, USA

Funding: DOE DE-SC0013571 NSF DGE-1650441
In order to reduce the vertical emittance at the Cornell Electron Storage Ring (CESR), we first measure and correct the vertical orbit, dispersion, and coupling. However, due to the finite resolution of our optics measurements, we still retain a significant residual emittance. In order to correct this further, we made use of the theory of sloppy models, according to which certain high-dimensionality systems can be modeled with significantly fewer "eigenparameters" that still contain most of the effect on the desired objective, in this case, the emittance.* However, we noted that using these knobs for tuning often resulted in increased vertical orbit errors. In an attempt to constrain these, we have applied multi-objective genetic algorithms to this problem. We have found that it can be more efficient to run such algorithms using our eigenparameters as the genes to be varied, as opposed to the raw magnet values. When running with the first 8 such knobs as genes, we can get either orbits or beam sizes as good as we obtain with our regular emittance-tuning algorithm which uses all the corrector magnets.
*K.S. Brown and J.P. Sethna, Phys. Rev. E 68, 021904 (2003).

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WEPAF042

Measurement of Beam yz Crabbing Tilt Due to Wake Fields Using Streak Camera at CESR

wakefield, positron, coupling, cavity

1905

S. Wang, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This research was supported by NSF PHYS-1068662, PHYS-1416318 and DMR-1332208.
Transverse vertical wake fields can increase the vertical emittance and distort the phase space of a bunch in a storage ring. Recently, we observed charge-dependent vertical beam size growth with a single scraper inserted through the top of the storage ring vacuum chamber. This apparent growth was due in large part to the yz coupling (vertical crabbing) induced by the wake field from the asymmetric scraper configuration. Here, we report a direct measurement of a small beam yz crabbing tilt using a streak camera. The recorded images (projected beam profiles in yz plane) are analyzed with three different methods, which yield consistent beam yz tilts. We found the directly-measured current-dependent beam tilts by the streak camera are consistent with the beam tilts calculated from a wake field model.

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WEPAK009

Applications of the Interferometric Beam Size Monitor at BESSY II

diagnostics, operation, electron, photon

2103

M. Koopmans, P. Goslawski, J.G. Hwang, A. Jankowiak, M. Ries, A. Schälicke, G. Schiwietz
HZB, Berlin, Germany

For the upgrade project of the BESSY~II storage ring to BESSY~VSR * an interferometric beam size monitor was designed and set up. Since this system uses visible light it can be upgraded efficiently to provide bunch resolved measurements. These are required for machine commissioning, development and to ensure long term quality and stability of user operation of BESSY~VSR. Various applications of the system are outlined and measurements are presented.
* A. Jankowiak et al., eds., BESSY VSR Technical Design Study, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany, June 2015. DOI: 10.5442/R0001

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WEPAK011

Development of the Electron-Beam Diagnostics for the Future BESSY-VSR Storage Ring

electron, diagnostics, laser, dipole

2110

G. Schiwietz, J.G. Hwang, M. Koopmans, M. Ries, A. Schälicke
HZB, Berlin, Germany

This contribution focusses on the different types of new or improved electron-beam monitors at BESSY II for bunch resolved measurements under future BESSY-VSR conditions. A new diagnostics platform, involving three different dipole beam lines will be built for different di-pole-related optical and THz methods. Our main concepts for robust future monitors for bunch length, beam size and position are presented in the following.

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WEPAL005

Beam Size Measurement and PSF Evaluate of KB Mirror Monitor at SSRF

SRF, optics, electron, photon

2151

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

Funding: Work supported by National Nature Science Foundation of China(11605213)
A Kirkpatrick Baez mirror imaging system was designed and installed to measure the transverse beam size and emittance of SSRF storage ring. Two crossed cylindrical mirrors are used to image the dipole source point in the horizontal and vertical direction. Both mirrors could be moved in and out in order to interchangeable with an original X-ray pinhole system. Hard X-ray with peak energy of 20.5 keV was focused at the X-ray scintillator camera. Aberration and point spread function which would cause image blur were evaluated. System commissioning and optimization have been done. PSF measurement was acquired using beam based calibration scheme by varying the beam images with different quadrupole settings and fitting them with the corresponding theoretical beam sizes.

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WEPAL026

High Repetition Rate, Single-Shot Electro-Optical Monitoring of Longitudinal Electron Bunch Dynamics Using the Linear Array Detector KALYPSO

electron, laser, radiation, FEL

2216

G. Niehues, E. Blomley, M. Brosi, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, L. Rota, M. Schuh, P. Schönfeldt, M. Weber
KIT, Eggenstein-Leopoldshafen, Germany
N. Hiller
PSI, Villigen PSI, Switzerland

Funding: This work is funded by the BMBF contract numbers: 05K13VKA and 05K16VKA.
High repetition rate diagnostics are required when detecting single-shot electro-optical (EO) bunch profiles. The KIT storage ring KARA (KArlsruhe Research Accelerator) is the first storage ring in the world that has a near-field EO bunch-profile monitor in operation. By imprinting longitudinal electron bunch profiles onto chirped laser pulses, single-shot detection is feasible. However, limitations of available detection systems are challenging: The constraints are either given by the repetition rate or the duration of the consecutive acquisitions. Two strategies can overcome these limitations: Based on the photonic time-stretch method, the ps laser pulses can be stretched to the ns range using km long fibers. The readout with a high-bandwidth oscilloscope then enables a single-shot detection at high repetition rates. The other strategy is the development of dedicated ultra-fast photodetector arrays allowing direct detection of the ps pulses at MHz repetition rates. We developed KALYPSO, a linear detector array with a DAQ allowing to record high data-rates over long time scales. Here, we present recent results of studies of the longitudinal electron bunch dynamics using KALYPSO.

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WEPAL027

Filling Pattern Measurements Using Dead-Time Corrected Single Photon Counting

photon, synchrotron, radiation, data-analysis

2219

B. Kehrer, E. Blomley, M. Brosi, E. Bründermann, A.-S. Müller, M. Schuh, P. Schönfeldt, J.L. Steinmann
KIT, Karlsruhe, Germany

Time-correlated single photon counting (TCSPC) is a versatile tool for various accelerator diagnostics aspects. Amongst others it allows a precise determination of the filling pattern. At the visible light diagnostics port at the Karlsruhe Research Accelerator (KARA), the KIT storage ring, a Single-Photon Avalanche Diode (SPAD) in combination with a histogramming device (PicoHarp) is used. To compensate for possible dead-time effects, a correction scheme was developed and tested successfully. The compensation increases the dynamic range in which accurate measurements are possible and avoids distortion of the measured filling pattern. This contribution presents the experimental setup, as well as a series of benchmark measurements.

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WEPAL028

Study of the Influence of the CSR Impedance on the Synchronous Phase Shift at KARA

impedance, synchrotron, simulation, radiation

2223

P. Schönfeldt, E. Blomley, M. Brosi, E. Bründermann, J. Gethmann, B. Kehrer, A.-S. Müller, A.I. Papash, J.L. Steinmann
KIT, Karlsruhe, Germany

Funding: This work has been supported by the German Federal Ministry of Education and Research (Grant No. 05K16VKA) and the Helmholtz Association (Contract No. VH-NG-320).
Measurements of the bunch current dependent synchronous phase shift are a standard method to characterize the impedance of a storage ring. To study this shift, different experimental approaches can be used. In this contribution, we first derive the phase shift caused by the impedance describing the emission of coherent synchrotron radiation (CSR) based on numerical simulations of the longitudinal phase space. The predicted shift is compared to measurement results obtained by time-correlated single photon counting.

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WEPAL047

Online Optimisation of the MAX IV 3 GeV Ring Dynamic Aperture

dynamic-aperture, sextupole, octupole, optics

2281

D.K. Olsson
MAX IV Laboratory, Lund University, Lund, Sweden

In order to improve the resilience of the MAX IV 3 GeV ring's beam to a horizontal dipole kick while at the design tunes (42.20, 16.28) the optimisation algorithm RCDS (Robust Conjugate Direction Search) was deployed. The algorithm was able to increase the horizontal acceptance by finding new settings for the sextupole and octupole magnets, whilst leaving the vertical acceptance virtually unchanged. Additionally, the optimisation increased the momentum acceptance of the lattice, increasing beam lifetime.

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WEPAL055

TPS Beam Trip Analysis and Dose Distribution

radiation, kicker, SRF, neutron

2302

B.Y. Chen, F.Y. Chang, S. Fann, C.S. Huang, C.H. Kuo, T.Y. Lee, C.C. Liang, W.Y. Lin, Y.C. Lin, Y.-C. Liu
NSRRC, Hsinchu, Taiwan

Failure analysis during TPS users operation is im-portant to improve the performance of the TPS storage ring. In this report, we discuss the particular radiation dose patterns, relevant to different beam trips, and the development of a tool to help us analyse this dose distri-bution. We will use this analysing tool to train our ability for future failure analysis to shorten the time it takes to find the problem.

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WEPAL057

Methods to Detect Error Sources and Their Application at the TPS

photon, kicker, cavity, injection

2305

C.H. Huang, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.Y. Wu
NSRRC, Hsinchu, Taiwan

For a low-emittance photon light source, beam stability is a very important property to attain a high-quality photon beam. While it is hard to avoid beam perturbations in a storage ring, it is more important to quickly find the source locations and to remove or eliminate the sources as soon as possible. In this report, we develop a method to identify the locations of multiple sources. For a source with a particular frequency, the relative phase between sources can also be obtained. This method has been a useful tool during TPS operation and its methodology and practical applications are described in this report.

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WEPMF008

Preliminary Designs and Test Results of Bipolar Power Supplies for APS Upgrade Storage Ring

power-supply, hardware, controls, operation

2381

J. Wang, I.A. Abid, R.T. Keane, G.S. Sprau
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.
The upgrade (APS-U) of the APS storage ring requires more than 1200 bipolar power supplies. Based on the performance requirement, the power supplies can be divided into two categories: fast bipolar power supplies for fast correctors and slow bipolar power supplies for trim coils and slow correctors. The common requirement of the power supplies is a bipolar output current up to ±15 A. The main difference is that the fast corrector power supplies require a small-signal bandwidth of 10 kHz. A prototype DC/DC power converter utilizing a MOSFET H-bridge circuit with a 500 kHz PWM was successfully developed through the R&D program, achieving the required bandwidth with less than 3-dB attenuation for a signal 0.5% of ±15 A. After the successful R&D program, the preliminary designs were performed to further improve the performance and to finalize the schematics, the PCB layouts, and the power supply constructions. The two types of the power supplies share the majority of the designs and features, with minor differences for the different bandwidth requirement. This paper presents the preliminary design, the key power supply functions and features, and the test results.

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WEPMF011

Design and Status of Sirius Light Source RF Systems

cavity, booster, LLRF, lattice

2391

R.H.A. Farias, A.P.B. Lima, L. Liu, F.S. Oliveira
LNLS, Campinas, Brazil

Sirius is the new synchrotron light source currently under construction at the site of the Brazilian Synchro-tron Light Laboratory (LNLS) in Campinas, Brazil. The facility comprises a 3 GeV electron storage ring, a full energy booster and a 150 MeV linac. This work provides a brief description of the RF system of the booster and storage ring, presenting their main characteristics and specification goals.

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WEPMF019

Conceptual Design of the eRHIC Storage Ring Magnets

dipole, sextupole, quadrupole, simulation

2407

H. Witte, J.S. Berg, S. Tepikian
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.
Presently the electron-ion collider eRHIC is under design, which aims to provide a facility with a peak luminosity of 10³⁴cm^-2sec^-1. Part of the eRHIC accelerator is the addition of an electron storage ring to the existing tunnel. This paper describes the magnets required for this storage ring. The necessary bending is provided by a triplet of dipole magnets, which generate excess bending to create additional radiation damping to allow a larger beam-beam tune shift. Each triplet consists of two long, low field magnets and a short, high-field magnet. This paper also describes the quadrupole and sextupole magnets necessary for this machine. All magnets require a large aperture to accommodate the beam-pipe.

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WEPMF020

Pulsed Systems for eRHIC Beam Injection and Extraction

injection, kicker, extraction, electron

2410

W. Zhang, M. Blaskiewicz, A. Hershcovitch, C.J. Liaw, H. Lovelace III, M. Mapes, G.T. McIntyre, J.-L. Mi, C. Montag, C. Pai, V. Ptitsyn, J. Sandberg, N. Tsoupas, J.E. Tuozzolo, G.M. Wang, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu
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.
The electron-ion collider eRHIC requires a variety of kickers and septa for injection and extraction of beams throughout the entire collider complex. We plan to use pulsed systems for beam injection and extraction in Electron RCS, Electron Storage Ring, and Hadron ring. In this paper, we describe the pulsed systems required for beam transfer in the eRHIC Ring-Ring Pre-conceptual Design. We will outline the parameter ranges, technology choices, and opportunities for research and development in pulsed power technology.

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WEPMF021

Magnet Design Considerations for an Ultralow Emittance Canadian Light Source

quadrupole, lattice, emittance, FEL

2413

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

The strong focusing requirements for ultralow emittance light sources result in high field magnets that are very close together. High fields are readily achieved by using small magnet gaps. This is possible due to the small beam sizes involved. Reduction in the physical aperture and the reduction in the good field region requirements results in magnets with compact transverse dimensions. The very strong focusing of the magnets results in very small drift spaces between the various magnetic elements. To keep these drift spaces clear magnets with recessed coils have been studied. In such magnets the coils do not stick out beyond the end of the magnet yoke in the longitudinal direction. By placing the coils on the outer yoke loss of efficiency can be avoided while maintaining good control of the higher order field harmonics. This is very well suited for quadrupole magnets where only two coils are required. Possible designs for gradient dipoles and sexutpoles are also considered.

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WEPMF072

Magnet Power Supplies for ALS-U

power-supply, magnet-design, dipole, sextupole

2538

G.C. Pappas, J.-Y. Jung, C.A. Swenson
LBNL, Berkeley, California, USA

The ALS-U project is an upgrade to the existing Advanced Light Source at Lawrence Berkeley Laboratory to a diffraction limited light source. To be able to achieve the small horizontal emittance of the ALS-U, the three bend achromats in the ALS will be replaced with nine bend achromats. Because the lifetime of the ALS-U beam will be significantly reduced, the plan is to use a swap out injection scheme between the storage ring and a new accumulator ring. The present plan is to use individual power supplies for each magnet in the storage ring, and series connected magnet strings for the accumulator ring. The sheer number of supplies needed, along with the tighter stability requirements for the ALS-U, is demanding in terms of the power supply requirements for stability and reliability. This paper will discuss the ALS-U magnet power supply requirements, and possible options to meet them.

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WEPML028

NEG Coated Vacuum Chambers and Bake-Out-Concept for the HESR at FAIR

dipole, quadrupole, vacuum, heavy-ion

2745

H. Jagdfeld, N.B. Bongers, J. Böker, P. Chaumet, F.M. Esser, F. Jordan, F. Klehr, G. Langenberg, D. Prasuhn, L. Semke, R. Tölle
FZJ, Jülich, Germany
A. Mauel, G. Natour, U. Pabst
Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics, Jülich, Germany

The High-Energy Storage Ring (HESR) is part of the international Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt. Forschungszentrum Jülich (IKP and ZEA-1) is responsible for the design and installation of the HESR. The HESR is designed for antiprotons and heavy ion experiments as well. Therefore the vacuum is required to be 10^-11 mbar or better. To achieve this extreme high vacuum (XHV), NEG coated chambers will be used in combination with common vacuum pumps to reach the needed pumping speed and capacity everywhere in the accelerator ring. For activation of the NEG material a bake-out system will be developed and installed. A bake-out test bench was used for checking the achievable end pressure and developing the bake-out system for the NEG coated chambers of the HESR. The results of the tests and the bake-out concept including the layout of the control system are presented. In addition, the temperature distribution of the dedicated heater jackets inside the dipole and quadrupole magnets are shown.

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WEPML047

Study on RF Coupler Kicks of SRF Cavities in the BESSY VSR Module

cavity, SRF, HOM, GUI

2804

A.V. Tsakanian, T. Mertens
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany
H.-W. Glock, J. Knobloch, M. Ries, A.V. Vélez
HZB, Berlin, Germany

The BESSY VSR upgrade of the BESSY II light source represents a novel approach to simultaneously store long (ca. 15ps) and short (ca. 1.7ps) bunches in the storage ring with the standard user optics. This challenging goal requires installation of four new SRF multi-cell cavities (2x1.5GHz and 2x1.75GHz) equipped with strong waveguide HOM dampers ensuring tolerable beam coupling impedance, necessary for stable operation. These cavities will operate at high 20MV/m in CW mode and at the zero-crossing phase according to the accelerating voltage. Consequently the transverse voltages will be maximum and can impact the transverse beam dynamics. The asymmetric character of those transverse kicks are caused by cavity fundamental power couplers (FPC) with strong monopole terms, introducing transverse kick to on-axis particles. Different FPC orientations were analyzed to optimize the net coupler kick from the four cavity chain. The coupler kick strength of each cavity is estimated taking into account accelerating mode amplitudes and phases required for operation in VSR mode.

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THXGBD4

Sirius Light Source Status Report

kicker, injection, booster, MMI

2886

A.R.D. Rodrigues, F.C. Arroyo, O.R. Bagnato, J.F. Citadini, R.H.A. Farias, J.G.R.S. Franco, R. Junqueira Leao, L. Liu, S.R. Marques, R.T. Neuenschwander, C. Rodrigues, F. Rodrigues, R.M. Seraphim, O.H.V. Silva
LNLS, Campinas, Brazil

Sirius is a Synchrotron Light Source Facility based on a 4th generation 3 GeV low emittance electron storage ring that is under construction in Campinas, Brazil. Presently the main tunnel for the accelerators is ready to start installations. The Linac tunnel was delivered earlier and the 150 MeV Linac from SINAP is almost ready to start commissioning early May. Commissioning of the storage ring is expected to start by the end of this year (2018). In this paper we briefly review the overall project parameters and design concepts and focus on highlights from the main subsystems.

Slides THXGBD4 [28.400 MB]

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THYGBF3

Challenges of FAIR Phase 0

operation, controls, MMI, experiment

2947

M. Bai, A. Adonin, S. Appel, R. Bär, M.C. Bellachioma, U. Blell, C. Dimopoulou, G. Franchetti, O. Geithner, P. Gerhard, L. Groening, F. Herfurth, R. Hess, R. Hollinger, H.C. Hüther, H. Klingbeil, A. Krämer, S.A. Litvinov, F. Maimone, D. Ondreka, N. Pyka, S. Reimann, A. Reiter, M. Sapinski, B. Schlitt, G. Schreiber, M. Schwickert, D. Severin, R. Singh, P.J. Spiller, J. Stadlmann, M. Steck, R.J. Steinhagen, K. Tinschert, M. Vossberg, G. Walter, U. Weinrich
GSI, Darmstadt, Germany

After two-year's shutdown, the GSI accelerators plus the latest addition of storage ring CRYRING, will be back into operation in 2018 as the FAIR phase 0 with the goal to fulfill the needs of scientific community and the FAIR accelerators and detector development. Even though GSI has been well known for its operation of a variety of ion beams ranging from proton up to uranium for multi research areas such as nuclear physics, astrophysics, biophysics, material science, the upcoming beam time faces a number of challenges in re-commissioning its existing circular accelerators with brand new control system and upgrade of beam instrumentations, as well as in rising failures of dated components and systems. The cycling synchrotron SIS18 has been undergoing a set of upgrade measures for fulfilling future FAIR operation, among which many measures will also be commissioned during the upcoming beam time. This paper presents the highlights of the challenges such as re-establishing the high intensity heavy ion operation as well as parallel operation mode for serving multi users. The status of preparation including commissioning results will also be reported.

Slides THYGBF3 [2.948 MB]

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THPAF014

Studies of the Single-Bunch Instabilities in the Booster of HEPS

booster, impedance, lattice, injection

2971

H.S. Xu, Z. Duan, J.L. Li, Y.M. Peng, S.K. Tian, N. Wang
IHEP, Beijing, People's Republic of China

High Energy Photon Source (HEPS), which is proposed in China, is an ultra-low emittance storage ring based synchrotron light source. Because of the requirement of the relatively high single-bunch charge, the booster may suffer from the single-bunch instabilities. A preliminary impedance model has been developed for the studies of collective instabilities in the booster. Based on this impedance model, the longitudinal and transverse single-bunch instabilities have been studied.

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THPAF030

PETRA III Storage Ring Performance Improvement Based on Multi-Objective Genetic Algorithms (MOGA)

injection, operation, multipole, dynamic-aperture

3018

X.N. Gavaldà, J. Keil, G.K. Sahoo, R. Wanzenberg
DESY, Hamburg, Germany

The performance of the 3th generation light sources relies on the beam lifetime and the injection efficiency, both related with the beam dynamic properties of the storage ring as momentum acceptance and dynamic aperture, respectively. High values of beam lifetime and injection efficiency are desirable to reduce the storage ring instabilities during injection, the radiation losses and the energy consumption of the facility. This paper reports the first application of Multi-Objective Genetic Algorithms (MOGA) to optimize the linear and non-linear beam dynamics of PETRA III storage ring. Genetic algorithms are a heuristic search that mimics the process of natural evolution to optimize problems with a high level of complexity, as in the case of PETRA III storage ring composed by hundreds of magnets. This computational method uses hundreds of CPUs. MOGA is used to maximize the dynamic aperture and the momentum acceptance finding new combinations of quadrupole and sextupole settings in a multi-dimensional parameter space maintaining the solutions in the level of ten picometers.

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THPAF046

Optics Measurements in Storage Rings Based on Simultaneous 3-Dimensional Beam Excitation

optics, dipole, synchrotron, betatron

3068

L. Malina, J.M. Coello de Portugal
CERN, Geneva, Switzerland
J.M. Coello de Portugal
UPC, Barcelona, Spain

Optics measurements in storage rings usually employ excitation in both transverse directions. This needs to be repeated at several different beam energies and is time-consuming. In this paper, we develop a new optics measurement technique, which excites the beam in all three spatial dimensions simultaneously. It allows measuring the linear optics and chromatic properties at the same time, leading to speed up of the optics measurements. The measurement method has been successfully demonstrated in the LHC using AC-dipoles and RF frequency modulation. Analysis methods have been derived for the 3-dimensional beam excitation case. We quantify the resolution of the measured optical quantities. The first results suggest that the added complexity does not deteriorate the resolution of the linear optics measurement. In the future, this method can serve as an operational tool to check the optics or even to correct it.

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THPAF085

Estimation of Dielectric Losses in the Bessy VSR Warm Beam Pipe Absorbers

cavity, HOM, GUI, wakefield

3185

T. Flisgen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
H.-W. Glock
HZB, Berlin, Germany
A.V. Tsakanian
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association.
Currently Helmholtz Zentrum Berlin prepares the update of the BESSY II ring to BESSY VSR. The updated ring will be capable to simultaneously store short and long bunches to satisfy the various user demands. For this sake, a cryomodule accommodating two 1.5 GHz and two 1.75 GHz superconducting cavities will be installed into the storage ring. The cavity string will be equipped with warm dielectric absorber rings at both ends. Together with the waveguide dampers of the cavities, these rings damp electromagnetic fields excited by the beam. This contribution presents the estimation of the dielectric losses in the beam pipe absorber rings of the BESSY VSR module. The presented approach is based on determining a broad band impedance of the dielectric ring by exciting the numerical model with a single broad band Gaussian bunch. Subsequently, the power deposited into the ring is estimated in frequency domain by multiplying the impedance with the square of the beam current for all considered harmonics of the beam. Finally, these power contributions are added up. In addition to details of the scheme, the contribution presents results for the recent absorber layout of the BESSY VSR string.

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THPAF086

Beam Dynamics Simulations for Operating a Robinson Wiggler at the MLS

wiggler, optics, operation, dynamic-aperture

3189

J. Li, J. Feikes, M. Ries
HZB, Berlin, Germany
T. Tydecks
CERN, Geneva, Switzerland

A Robinson wiggler is planned to be installed in the storage ring of the Metrology Light Source (the MLS). The Robison wiggler (RW) is a device consisting of a chain of combined-function magnets (CFMs), intended to manipulate the damping partition numbers and thus adjust the longitudinal emittance. The objective is to lengthen the bunch in order to improve the Touschek lifetime. However, the nonlinear perturbation of the beam dynamics due to the Robinson wiggler could limit the achievable improvement. Therefore, a symplectic method of modeling the wiggler has been established to study these nonlinear effects. Optimized solutions have been developed for both the ramping procedure and the future daily operation of the wiggler and are presented in this paper.

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THPAK031

Suppression of Longitudinal Coupled Bunch Instability by Harmonic Cavity in UVSOR Electron Storage Ring

damping, synchrotron, HOM, cavity

3280

A. Mochihashi
KIT, Eggenstein-Leopoldshafen, Germany
M. Fujimoto, K. Hayashi, M. Katoh
UVSOR, Okazaki, Japan
J. H. Hasegawa, M. Hosaka, M. Hosaka, Y. Takashima, Y. Takashima
Nagoya University, Nagoya, Japan
M. Hosaka, Y. Takashima
Aichi Synchrotron Radiation Center, Aichi, Japan
M. Katoh
Sokendai - Okazaki, Okazaki, Aichi, Japan

In the UVSOR electron storage ring, which is dedicated for a VUV synchrotron radiation light source, a longitudinal coupled bunch instability (LCBI) is observed in multi-bunch operation. To suppress the LCBI, we routinely operate a third harmonic cavity (HCV) in a passive mode. By properly tuning HCV, the instability is almost completely suppressed. Because of the lower beam energy (750 MeV) and brilliant beam emittance (17.5 nm-rad), the Touschek effect becomes severe in the UVSOR. To guarantee enough beam lifetime, we also apply HCV for lengthening the bunch. The suppression of the instability and increasing the beam lifetime are crucial benefits by HCV for the UVSOR. However, not only the origin of the LCBI but also the Landau damping effect by HCV has not been understood systematically yet. We have noticed that one of the HOMs at HCV itself could cause the LCBI and observed the behavior of the instability, which strongly depends on the beam current. From the experiment we have discussed the cause of the instability with the HOM theory. We have also tried to observe synchrotron tune spread and discussed a competition between the Landau damping and the instability growth.
Present affiliation of the first auther : Karlsruhe Institute of Technology

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THPAK032

Elaborated Modeling of Synchrotron Motion in Vlasov-Fokker-Planck Solvers

simulation, synchrotron, electron, damping

3283

P. Schönfeldt, T. Boltz, A. Mochihashi, A.-S. Müller, J.L. Steinmann
KIT, Karlsruhe, Germany

Funding: Funded by the German Federal Ministry of Education and Research (Grant No. 05K16VKA) & Initiative and Networking Fund of the Helmholtz Association (contract number: VH-NG-320).
Solving the Vlasov-Fokker-Planck equation is a well-tested approach to simulate dynamics of electron bunches self-interacting with their own wake-field. Typical implementations model the dynamics of a charge density in a damped harmonic oscillator, with a small perturbation due to collective effects. This description imposes some limits to the applicability: Because after a certain simulation time coherent synchrotron motion will be damped down, effectively only the incoherent motion is described. Furthermore - even though computed - the tune spread is typically masked by the use of a charge density instead of individual particles. As a consequence, some effects are not reproduced. In this contribution, we present methods that allow to consider single-particle motion, coherent synchrotron oscillation, non-linearities of the accelerating voltage, higher orders of the momentum compaction factor, as well as modulations of the accelerating voltage. We also provide exemplary studies - based on the KIT storage ring KARA (KArlsruhe Research Accelerator) - to show the potential of the methods.

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THPAK053

Side Effects of Local Bump in TPS Storage Ring

sextupole, quadrupole, radiation, dipole

3340

M.-S. Chiu, C.H. Chen, J.Y. Chen, P.J. Chou, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is a low-emittance 3-GeV light source at National Synchrotron Radiation Research Center. Five in-vacuum undulator beamlines were delivered to users on Sep. 22, 2016. Another 2 EPU beamlines will be open to user in near future. In the beginning, the local bump was used to do ID spectrum optimization since 2016. After this procedure, the ID spectrum are consistent between theoretical simulation and measurement. Recently, we found the local bump will cause tune shift and orbit distortion. In this paper, we will present the effect of local bump in TPS.

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THPAK055

Suppression of Transverse Beam Instabilities by Stripline Kickers at TPS

kicker, impedance, feedback, damping

3346

P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng, F.H. Tseng
NSRRC, Hsinchu, Taiwan

Collective beam instabilities could limit the accelerator performance if proper countermeasures are not in place. Active beam feedback systems are commonly used to suppress beam instabilities. The resistive wall impedance including phase-II insertion devices at TPS are calculated with analytical formulas. The growth rate of transverse coupled bunch instabilities due to wall impedance is estimated by theory. The RF properties of existing stripline kickers in TPS are analyzed with a 3-D electromagnetic simulation code GdfidL. Based on the above analysis, the requirements for a beam feedback system are calculated and the results are reported.

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THPAK088

Matrix Representation of Lie Transform in TensorFlow

network, simulation, GPU, linear-dynamics

3438

A.N. Ivanov, S.N. Andrianov, N.V. Kulabukhova, A.A. Sholokhova
St. Petersburg State University, St. Petersburg, Russia
E. Krushinevskii, E. Sboeva
Saint Petersburg State University, Saint Petersburg, Russia

In the article, we propose an implementation of the matrix representation of Lie transform using TensorFlow as a computational engine. TensorFlow allows easy description of deep neural networks and provides automatic code execution on both single CPU/GPU and cluster architectures. In this research, we demonstrate the connection of the matrix Lie transform with polynomial neural networks. The architecture of the neural network is described and realized in code. In terms of beam dynamics, the proposed technique provides a tool for both simulation and analysis of experimental results using modern machine learning techniques. As a simulation technique one operates with a nonlinear map up to the necessary order of nonlinearity. On the other hand, one can utilize TensorFlow engine to run map optimization and system identification problems.

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THPAK113

Cavity Characterization Studies With the Latest Revision of YACS

cavity, coupling, superconducting-cavity, higher-order-mode

3503

B.D. Isbarn, S. Koetter, B. Riemann, M. Sommer, T. Weis
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF under contract no. 05K13PEB.
YACS is a 2.5D finite element method solver capable of solving for the full 3D eigenfrequency spectra of resonant axisymmetric structures while reducing the computational problem to a 2D rotation plane. The most recent revision of YACS now supports arbitrary order basis functions for the geometry and field discretization. In earlier revisions of YACS spurious modes were introduced by increasing the order of either the geometry or field basis functions. To prevent the emergence of spurious modes, YACS now matches the function spaces of the in-plane and out-plane function basis, and thus yields spurious free solutions. To demonstrate the capabilities of YACS, extensive cavity characterization studies on curved multicell microwave cavities are presented. Due to the combined utilization of the rotation symmetry, higher order basis functions and curved elements, eigenfrequency spectra above 10 GHz for L-band multicell structures can be easily obtained.

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THPAK114

Evaluation of an Interior Point Method Specialized in Solving Constrained Convex Optimization Problems for Orbit Correction at the Electron Storage Ring at DELTA

software, feedback, electron, closed-orbit

3507

S. Koetter, A. Glaßl, B.D. Isbarn, D. Rohde, M. Sommer, T. Weis
DELTA, Dortmund, Germany

The slow orbit feedback at the electron storage ring at DELTA will be upgraded with new software. Finding a set of dipole-field-strength variations which minimize the deviation of the orbit from a reference orbit requires solving a convex optimization problem subject to inequality constraints. This work focuses on exploiting properties of a special type of interior point methods, which can solve this problem, for orbit correction at DELTA. After comparing runtimes of an interior point method to a Newton-like optimization algorithm, the performance of the new slow-orbit-feedback software is assessed based on measurement results.

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THPAK139

Lost Muon Studies for the Muon g-2 Experiment at Fermilab

positron, experiment, background, resonance

3573

S. Ganguly, K. T. Pitts
University of Illinois at Urbana-Champaign, Urbana, USA
J.D. Crnkovic
BNL, Upton, Long Island, New York, USA
C. C. Polly
Fermilab, Batavia, Illinois, USA

The Fermilab Muon g-2 experiment aims to measure the muon anomalous magnetic moment aμ with an unprecedented precision of 140 parts per billion (ppb), a four-fold improvement over the 540~ppb precision obtained by the BNL Muon g-2 Experiment. This study presents preliminary work on estimating the muon losses by using double coincidences in the calorimeters.

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THPAK144

A Pseudospectral Method for Solving the Bloch Equations of the Polarization Density in e^- Storage Rings

polarization, electron, ion-effects, synchrotron

3589

K.A. Heinemann, O. Beznosov, J.A. Ellison
UNM, Albuquerque, New Mexico, USA
D. Appelö
University of Colorado at Boulder, Boulder, USA
D.P. Barber
DESY, Hamburg, Germany

Funding: Work supported by DOE under DE-SC0018008
We consider the numerical evolution of Bloch equations for the polarization density in high-energy electron storage rings. Equilibrium polarization is well characterized by the DK formulas for current rings, but deviations may be important at the high energies we have in mind. We believe the Bloch equations derived in* give a more accurate description at all energies. These form a system of three coupled linear partial differential equations for the three components of the polarization density. Following** we formulate the equations in action-angle variables and approximate the Fokker-Planck terms. We aim to integrate these equations numerically in order to approximate the equilibrium and compare with the DK formulas. The smoothness and simple geometry of the problem makes it amenable to pseudospectral discretization using Fourier modes in the angles and Chebyshev polynomials in the actions, leading to a large ODE system. We will explore time stepping algorithms for the needed long time integration. Here, we present results for simple models checking the accuracy of the numerical method but note that our ultimate goal is to simulate polarization in the FCC and CEPC rings.
* Ya.S.Derbenev, A.M.Kondratenko, Sov. Phys. Dokl., 19, p.438 (1975).
** D.P.Barber, K.Heinemann, H.Mais, G.Ripken,
A Fokker-Planck treatment of stochastic particle motion…,
DESY-91-146, 1991.

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THPAK147

Super-Period Multi-Bend Achromat Lattice with Interleaved Dispersion Bumps for the HALS Storage Ring

lattice, sextupole, emittance, controls

3597

Z.H. Bai, L. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

We have proposed a multi-bend achromat (MBA) lattice concept, called the MBA with interleaved dispersion bumps, in which two pairs of interleaved dispersion bumps are created in each lattice cell. Due to that many nonlinear effects can be effectively cancelled out within one cell and also many knobs can be used for nonlinear optimization, this MBA concept has given both large dynamic aperture (DA) and large dynamic momentum aperture in the lattice design of the Hefei Advanced Light Source (HALS). In this paper, to further enlarge DA, we extend the concept to the case of a super-period lattice consisting of two cells. In the super-period lattice, there are 1.5 pairs of bumps in each cell. A super-period 7BA lattice is preliminarily designed for the HALS, and a larger DA is obtained.

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THPAK148

Preliminary Study of a Nine-Bend Achromat Lattice for a Diffraction-Limited Storage Ring

lattice, emittance, sextupole, synchrotron

3600

P.H. Yang, Z.H. Bai, L. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

In recent years, multi-bend achromat (MBA) lattices have been widely used for the design of diffraction-limited storage rings (DLSRs) being developed around the world as the next-generation storage ring synchrotron sources. To better solve the problem of very serious non-linear dynamics in the DLSR lattice design, recently we proposed a new MBA lattice concept called the MBA lattice with interleaved dispersion bumps *, which was then applied to designing 7BA lattices for the Hefei Ad-vanced Light Source (HALS), with the result showing rather good nonlinear dynamics performance. In this paper, a 9BA lattice also following our MBA concept is preliminarily designed as a possible option for the HALS with a natural emittance of less than 30 pm·rad. Since generally the 9BA lattice can have a much lower emit-tance than the usually used 7BA lattice, the work in the paper will provide an inspiration for the existing third-generation synchrotron sources to upgrade to DLSRs with much lower emittances.
* Zhenghe Bai et al., MOPH13, Proc. SAP2017, Jishou, China, 2017.

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THPAK153

Linac Optics Correction With Trajectory Scan Data

quadrupole, linac, optics, lattice

3606

X. Huang, Y.-C. Chao, T.J. Maxwell
SLAC, Menlo Park, California, USA
T. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

We proposed and tested a scheme to measure and correct linac optics by scanning the beam trajectory in the horizontal and vertical phase spaces. The trajectory data are compared to tracking data in a fitting scheme, from which we can derive the quadrupole strength errors. Simulation is carried out to evaluate the requirements and the performance of the method. The method is experimentally applied to FEL linacs.

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THPAL013

First Serial Magnetic Measurements of the NICA Collider Twin-Aperture Dipoles

collider, dipole, booster, superconducting-magnet

3645

M.M. Shandov, V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin
JINR, Dubna, Russia
I.I. Donguzov, M. A. Kashunin, V. A. Mykhailenko, T.A. Parfylo, A.V. Shemchuk, D.A. Zolotykh
JINR/VBLHEP, Dubna, Moscow region, Russia

NICA is a new accelerator complex under construction at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, to study properties of hot and dense baryonic matter. Magnetic system of the NICA collider includes 80 twin-aperture dipole and 86 quadrupole superconducting magnets. The collider twin-aperture magnet is 1.94 m long, 120 mm/70 mm (h/v) aperture with window-frame design similar to the Nuclotron magnet. The measurement of the magnetic field parameters is supported to be conducted for both apertures of each collider magnet. This paper describes magnetic measurements methods and the development of the dedicated system for serial dipole magnets of the NICA collider.

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THPAL028

Commissioning of the Bunch-by-Bunch Feedback System in the MAX IV 1.5 GeV Ring

feedback, cavity, kicker, synchrotron

3688

D. Olsson, Å. Andersson, F.J. Cullinan, P.F. Tavares
MAX IV Laboratory, Lund University, Lund, Sweden

The MAX IV 1.5 GeV ring is an electron storage ring for production of synchrotron light in the IR to soft X-ray spectral range. The ring will deliver light to its first users during 2018. Bunch-By-Bunch (BBB) feedback has been needed to suppress coupled-bunch mode instabilities (CBMIs), and the feedback has this far been provided in all three planes by a single stripline kicker. This is done by combining the horizontal and vertical baseband feedback signals with the longitudinal feedback signal that is upconverted to the 150 MHz - 250 MHz range. The combined signal is then fed to two stripline electrodes. The layout of the BBB feedback system in the MAX IV 1.5 GeV ring is presented in this paper. Results from instability studies are also discussed.

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THPAL046

Energy-Savings for the TPS Booster RF System at the NSRRC in Taiwan

controls, booster, timing, injection

3748

F.-T. Chung, F.Y. Chang, L.-H. Chang, M.H. Chang, S.W. Chang, L.J. Chen, Y.T. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

In this paper, we discuss an energy-savings control sys-tem for the Taiwan Photon Source (TPS) booster RF sys-tem. During top-up storage ring operation, a timing con-trol is activated to reduce the booster RF transmitter en-ergy consumption when no injection is required. When-ever injection into the TPS storage ring is needed, the booster RF transmitter is immediately adjusted to operat-ing conditions. This timing-control system will save an energy of 380, 000 kWh annually.

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THPAL050

Beam Dynamics of the First Beams for the IFMIF-EVEDA RFQ Commissioning

operation, controls, synchrotron, site

3754

C.S. Chen, W.S. Chan, Y.Y. Cheng, Y.-C. Chung, C.Y. Liu, Y.-H. Liu, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

Since December 31th 2014, the first synchrotron light from Taiwan Photon Source (TPS) was stored in the storage ring, the challenge to operate both Taiwan Light Source (TLS) and TPS smoothly and reliably became a significant issue for all members in NSRRC. On the one hand, the beam quality of former TLS must not been impaired due to the occupied resources by TPS, on the other hand, the most efforts were devoted to achieving steady operation of TPS. In order to operate both ring stably, some mutual backup structures were designed in the compressed air system and the chilled water system between TLS and TPS. The primary advantage of these mutual backup systems is minimizing the risk of beam-trip while any one of the utility system fails. Secondly, the mutual backup structures provide more flexible usage to accomplish energy conservation. From both risk-reduction and energy conservation points of view, the backup systems will do a great deal of good in the future.

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THPAL056

Vibration Measurements in the TPS Vacuum System

vacuum, radiation, synchrotron, synchrotron-radiation

3772

Y.C. Yang, C.K. Chan, C.-C. Chang, C.S. Chen, J. -Y. Chuang, Y.M. Hsiao, C.C. Liang, Y.Z. Lin
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is currently operated in top-up mode for users. In order to improve the stability of the synchrotron light source, vibrations related to the vacuum system have been investigated and improved by turning off pumping systems and reducing the flow rate in chamber cooling water circuits. In this paper, vibrations in different vacuum chambers with normal cooling water condition were investigated, their sources were recorded and clarified and properties of different materials for water tubes were also compared.

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THPAL057

Development of the Aluminum Beam Duct for the Ultra-Low Emittance Light Source

vacuum, experiment, impedance, emittance

3775

G.-Y. Hsiung, J.-R. Chen, C.M. Cheng, S-N. Hsu, H.P. Hsueh, Y.C. Yang
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

The future light source with ultra-low emittance, typically < 500 pm rad, requests the beam duct with inner aperture < 20 mm for the electron storage ring. Besides, the cross section of the beam duct must be kept smooth for lowering the impedance. The aluminum extruded beam duct of 10 mm inside and 1 ~ 2 m in length was developed for this purpose. The beam duct was machined in ethanol to obtain a clean surface for a lower thermal outgassing rate. To mitigate the impedance of the flange connection, a special designed diamond-edge gasket and the aluminum flange without knife edge were developed. The inner diameters of both flange and gasket, 10 mm, are the same as that of beam duct. The sealing of the gasket has been proved leak-tight. The ultimate pressure and the thermal outgassing rate of the beam duct has achieved < 2.0·10^-10 Torr and < 1.4·10^-13 Torr l/(s cm²), respectively after baking. Those results fulfill both the ultrahigh vacuum and lowest impedance are applicable for the next generation ultra-low emittance light source.

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THPAL078

In-Vacuum Lambertson Septum for SPEAR3 Low Emittance Injection

septum, simulation, vacuum, injection

3831

M.A.G. Johansson, J. Langton, J.A. Safranek
SLAC, Menlo Park, California, USA
S.C. Gottschalk
STI Magnetics LLC, Woodinville, USA

Funding: Work supported by DOE Contract No. DE-AC02-76SF00515
A new in-vacuum Lambertson septum magnet is being designed for the SPEAR3 storage ring, intended to replace the existing septum to allow injection into a new lower emittance operation mode for SPEAR3. The new septum design is constrained to fit in the same length and have the same bend angle as the existing injection septum, so as to minimize changes to surrounding storage ring and transfer line components, while also meeting stringent requirements on the stored beam leakage field. This has led to a design using Vanadium Permendur alloy for the septum pole pieces, with shaping of the inner profile of the stored beam channel to minimize the leakage fields indicated in 2D and 3D magnetic simulations.

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THPAL107

Three Years of Operational Experience With the Solaris Vacuum System

vacuum, electron, MMI, synchrotron

3888

A.M. Marendziak, M. Rozwadowski, T. Sobol, M.J. Stankiewicz, A.I. Wawrzyniak
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

Solaris, a 1.5 GeV third generation synchrotron light source, was commissioned in 2016 April and is currently operated in decay mode. Two beamlines PEEM/XAS and UARPES were installed and now are being commis-sioned. Three more PHELIX, XMCD and diagnostic beamlines have received funding and will be installed and commissioned in next few years. With total accumu-lated beam dose near to 690 A.h and three orders of mag-nitude reduction of outgassing the design goal of 500 mA beam current and electron energy of 1.5 GeV has been achieved. As the beam current was increased, a few vacu-um problems were encountered, including vacuum leaks in RF and arc sectors and unexpected pressure bursts near photon absorbers. Lessons learned and operational expe-rience will be presented and discussed in this paper.

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THPAL108

In-Situ Characterization of Normal Conducting RF Cavities in Solaris Light Source Storage Ring

cavity, HOM, simulation, ISOL

3891

P.B. Borowiec, A.I. Wawrzyniak
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland
J. Björklund Svensson
Lund University, Division of Atomic Physics, Lund, Sweden

The SOLARIS 1.5 GeV storage ring is equipped with two 100 MHz active cavities and two 3rd harmonic passive cavities. They are in operation since 2015. For control of their respective working points, knowledge about cavity voltage and higher order mode (HOM) frequency spec-trum is mandatory. After their installation in the storage ring and connection of the RF feeder to a high power isolator and a transmitter, the influence of the external elements on the quality factor and the HOM spectrum should be verified with respect to simulations of a simpli-fied model of a stand-alone cavity. This paper will pre-sent results of in-situ cavity measurements to qualify the HOM placement and their quality factor. HOM meas-urements have been performed in the range 100 MHz to 1.3 GHz for active cavities and 300 MHz to 1.5 GHz for 3rd harmonic cavities at three different temperatures under ultra-high vacuum conditions for each cavity separately. The measurement and analysis methodology will also be presented

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THPMF002

Studies for Injection with a Pulsed Multipole Kicker at ALBA

injection, kicker, lattice, octupole

4030

G. Benedetti, U. Iriso, M. Pont, D. Ramos Santesmases
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
E. Ahmadi
ILSF, Tehran, Iran

Injection into the ALBA storage ring presently uses a conventional local injection bump with four dipole kickers. However, following the promising results of the first tests with single multipole kicker injection at other light sources, studies to implement this new injection scheme have been started for ALBA. Two possible designs for the kicker have been considered: a pure octupole and a non-linear magnet similar to the BESSY type. A comparison between the expected performances of the two kicker designs has been carried out in terms of injection efficiency and transparency for the users. This paper summarises the beam dynamics results from multi-particle tracking simulations and the proposed kicker magnet design.

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THPMF006

Control of the Nonlinear Dynamics for Medium Energy Synchrotron Light Sources

lattice, controls, optics, synchrotron

4037

J. Bengtsson, R. Bartolini, H. Ghasem, B. Singh
DLS, Oxfordshire, United Kingdom
A. Streun
PSI, Villigen PSI, Switzerland

MAX-IV has introduced a paradigm shift in the design philosophy for the "Engineering-Science" in the quest for a diffraction limited Synchrotron Light Source. Similarly, SLS-2 has introduced a systematic method for controlling the Linear Optics beyond some 20 years of TME inspired paper designs; by introducing Reverse Bends to disentangle dispersion and focusing, which enables Longitudinal Gradient Bends to efficiently reduce the emittance. Similarly, we outline a systematic approach for how to control the Nonlinear Dynamics for these systems, by a method that was pioneered for the conceptual design of the Swiss Light Source in the mid-1990s; subsequently benchmarked and validated by the commissioning.

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THPMF007

Commissioning of the Hybrid Superconducting/Normal Conducting RF System in the Diamond Storage Ring

cavity, operation, LLRF, HOM

4042

C. Christou, A.G. Day, P. Gu, P.J. Marten, S.A. Pande, D. Spink, A. Tropp
DLS, Oxfordshire, United Kingdom

Two 500 MHz HOM damped normal conducting cavities have been installed in the Diamond storage ring to ensure continuity of operation of Diamond in the event of a failure of one of the two existing superconducting cavities. Following receipt from the manufacturer, the cavities were incorporated into an assembly including vacuum pumping, cooling and interlocked diagnostics and then tested for vacuum integrity and RF performance. Both cavities were then conditioned up to high power in Diamond's RF test facility before being installed in the storage ring in August and November 2017. Conditioning and operation has been carried out using a new digital LLRF system. Results of acceptance tests and commissioning with power and beam are presented, together with the current status of the hybrid RF system and options for further improvement of the system in the near future.

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THPMF008

Conceptual Design of an Accumulator Ring for the Diamond II Upgrade

emittance, injection, lattice, dynamic-aperture

4046

I.P.S. Martin, R. Bartolini
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

Diamond Light Source is in the process of reviewing several lattice options for a potential storage ring upgrade. As part of these studies, it has become clear that a substantial reduction in emittance can be achieved by adopting an on-axis injection scheme, thereby relaxing the constraints on the dynamic aperture. In order to achieve the necessary injected bunch properties for this to be viable, a new accumulator ring would be needed. In this paper we review the requirements placed on the accumulator ring design, describe the lattice development process and analyse the performance of the initial, conceptual design.

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THPMF011

Femtosecond Laser Ablation for Manufacturing of X-ray Lenses and Phase Corrector Plates

optics, laser, photon, experiment

4057

S.P. Antipov
Euclid TechLabs, LLC, Solon, Ohio, USA
L. Assoufid, W.C. Grizolli, J. Qian, X. Shi
ANL, Argonne, Illinois, USA

Funding: DOE SBIR
The next generation light sources such as diffraction limited storage rings and high repetition rate free electron lasers (FELs) will generate X-ray beams with significantly increased peak and average brilliance. These future facilities will require X-ray optical components capable of handling large instantaneous and average power densities while tailoring the properties of the X-ray beams for a variety of scientific experiments. In this paper we report on research and development of a single crystal diamond compound refractive lens. Diamond lenses presented here are fabricated by fs-laser cutting and subsequent polishing. Grating interferometry measurement data of these lenses had been performed at the Advanced Photon Source (Argonne). Besides the lenses, we fabricated and tested several phase correction plates, a refractive elements designed to correct for cumulative X-ray beam aberrations.

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THPMF013

The Stripline Kicker Prototype for the CLIC Damping Rings at ALBA: Installation, Commissioning and Beam Characterisation

kicker, extraction, synchrotron, impedance

4062

M. Pont, N. Ayala, M. Carlà, T.F.G. Günzel, U. Iriso, Z. Martí, R. Monge, A. Olmos, F. Pérez, M. Quispe
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
M.J. Barnes, C. Belver-Aguilar, Y. Papaphilippou
CERN, Geneva, Switzerland

The extraction system for the CLIC Damping Rings has very tight specifications. Therefore a full characterisation of the behaviour of the stripline kicker under conditions as close as possible to the expected working conditions will be very valuable. To that end the CLIC stripline has been installed in the ALBA Synchrotron Light Source and has been characterised with beam. Prior to its installation, the effect of the stripline kicker on the machine impedance has been assessed. The installation has required the design of an absorber to screen the stripline from synchrotron radiation and additional BPMs have been installed for a better kick angle determination. The commissioning of the stripline with beam has been performed following closely beam parameters, pressure and temperature. The studies with beam include the determination of the longitudinal and transverse impedance of the kicker*, the field homogeneity when excited with a dc field and the field ripple when pulsed. This contribution reports on the first experience with the stripline kicker for the CLIC DR in the ALBA storage ring and presents the results of the initial beam characterisation.
* M. Carla et al., "Beam based impedance measurements of the CLIC stripline at ALBA", Proc. of IPAC'2017.

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THPMF020

A 4th Generation Light Source for South-East Europe

lattice, emittance, SRF, synchrotron

4084

H. Ghasem, R. Bartolini
DLS, Oxfordshire, United Kingdom
D. Einfeld
ESRF, Grenoble, France

In Europe, most of the Synchrotron Light Sources are located in the middle, west and northern regions while the south-east is still lacking any major project. Hence a new initiative has been set up to propose the construction of a 4th Generation Light Source in that region. Design requirements limit the beam energy between 2.5 GeV to 3 GeV, the circumference is limited to 350 m, the emittance should be smaller than 250 pm rad and at least 14 to 16 straights have to be available for the users. Several mag-net configurations have been investigated and the results revealed that the HMBA lattice can fully meets the requirements and is therefore proposed for the Light Source in the SEE-region of Europe. These studies show that for a 4th Generation Light Source with energies up to 3 GeV a circumferences of 350 m will be adequate.

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THPMF030

VSR Injector Upgrade at BESSY II

booster, cavity, injection, kicker

4110

T. Atkinson, P. Goslawski, J.G. Hwang, M. Ries
HZB, Berlin, Germany
T. Flisgen, T. Mertens
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany

BESSY VSR is a fully funded project at the Helmholtz-Zentrum in Berlin (HZB). The objective is to produce simultaneously both long and short pulses in the storage ring. The implications for the existing injector systems and the upgrade strategy are presented. Envisaged is a global upgrade which includes additional accelerating structures to reduce the bunch length in the booster, orbit measurements and implementing longitudinal feedback.

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THPMF042

Beam Based Measurement of Injection Parameters at KEK-PF

injection, kicker, septum, beam-transport

4152

K. Hirano
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
K. Harada, N. Higashi, Y. Kobayashi, S. Nagahashi, T. Obina, R. Takai, H. Takaki, A. Ueda
KEK, Ibaraki, Japan

KEK-PF is a 2.5 GeV synchrotron radiation facility. In recent years, the injection efficiency using conventional pulsed septum and kicker magnets has decreased. The main cause of this problem seems to be the change of the injection parameters due to the accumulation of the errors including the effect of the earthquake on March 11, 2011. For the improvement of the injection efficiency, the precise and detailed parameters of the beam injection under present configuration are essential. In order to fix these parameters, we measure the response of the pulsed magnets by using injected and stored beams. In this presentation, we show the beam based measurement and the simulation results for the PF ring injection system.

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THPMF043

Development and Present Status of Photon Factory Light Sources

injection, septum, operation, vacuum

4155

T. Honda, Y. Kobayashi, S. Nagahashi, R. Takai
KEK, Ibaraki, Japan

Photon Factory of KEK manages two light sources, Photon Factory storage ring (PF-ring) and Photon Factory Advanced Ring (PF-AR) with an energy of 2.5 GeV and 6.5 GeV, respectively. Although it is unfortunate that the operation time of the accelerators is decreasing recent years due to a budget shortage and some unavoidable reconstructions, we are continuing the operation with a low failure rate and constructing a new beamline based on a novel undulator. Preparing for the start of the physics run of Super KEKB Factory, a new full energy beam transport line from the injector LINAC to PF-AR was constructed. With an installation of pulsed quadrupole magnets for the LINAC, continuous top-up injection has been established simultaneously for the four storage rings of PF and Super KEKB, and the operation of them has become compatible. As a result of increasing the injection energy of PF-AR form 3 GeV to 6.5 GeV, the beam instability during the injection disappeared, and the stability and efficiency of the injection improved significantly.

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THPMF051

Research of a Locally-round Beam in HEPS Storage Ring Using Solenoids

solenoid, dynamic-aperture, emittance, undulator

4175

C.C. Du, J.Q. Wang
IHEP, Beijing, People's Republic of China

"Round beam", that is, a beam with equivalent transverse emittance, is expected for a significant fraction of the beamline users in light sources. We investigate the possibility of reaching round beam in a storage ring, by means of a local exchange of the apparent horizontal and vertical emittance, performed with solenoids in a dedicated insertion line in the storage ring. In this paper, we show that a locally-round beam can be achieved by using solenoid in High Energy Photon Source (HEPS) storage ring, particularly to one of the design having natural emittance of 34.2 pm·rad.

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THPMF052

The Swap-Out Injection Scheme for the High Energy Photon Source

injection, booster, kicker, extraction

4178

Z. Duan, J. Chen, Y.Y. Guo, Y. Jiao, J.L. Li, Y.M. Peng, J.Q. Wang, N. Wang, G. Xu, H.S. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by Natural Science Foundation of China (No.11605212).
The on-axis swap-out scheme is a promising injection scheme for di raction-limited storage rings, since it only re- quires a rather small dynamic aperture and thus potentially allows a higher brightness compared to traditional o -axis injection schemes. However, a full charge injector is neces- sary for this scheme and its design can be nontrivial, in par- ticular to satisfy the large single bunch charge requirements in special lling patterns for timing experiments. In the High Energy Photon Source, we propose using the booster also as a high energy accumulator ring to recapture the spent bunches extracted from the storage ring, so as to relax the challenges in generation and acceleration of bunches with a high charge, and as a cost-e ective solution compared to building a dedicated full energy accumulator ring. In this paper, the beam dynamics issues of this scheme will be presented, trade-o s between the storage ring and booster beam parameters and hardware specifications will also be discussed.

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THPMF055

Ion Instability Simulation in the HEPS Storage Ring

electron, simulation, emittance, lattice

4189

S.K. Tian, Y. Jiao, N. Wang
IHEP, Beijing, People's Republic of China
K. Ohmi
KEK, Ibaraki, Japan

The High Energy Photon Source (HEPS), a kilometre scale storage ring light source, with a beam energy of 6 GeV and transverse emittances of a few tens of pm.rad, is to be built in Beijing and now is under design. We investigate the ion instability in the storage ring with high beam intensity and low-emittance. We performe a weak-strong simulation to show characteristic phenomena of the instability in the storage ring.

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THPMF060

Touschek Beam Loss Simulation for Light Source Storage Rings

electron, scattering, coupling, simulation

4206

M. Takao, K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan
Y. Shimosaki
JASRI, Hyogo, Japan
K. Soutome, H. Tanaka
RIKEN SPring-8 Center, Hyogo, Japan

In light source storage rings, it is important to know the distribution of lost electrons due to the Touschek scattering for protecting insertion devices (IDs) from radiation damage. This will become crucial especially in future light sources where narrow gap in-vacuum IDs are normally used. While the Touschek scattered electron begins to oscillate in the horizontal direction with the amplitude proportional to the dispersion at the scattering point and to the momentum deviation after scattering, the motion is converted into the vertical direction due to the betatron coupling and some of the scattered electrons are lost at the narrow gaps of in-vacuum IDs. The momentum deviation by the Touschek scattering reaches 5% more, and according to which the vertical oscillation is more excited. Hence electrons even scattered at small horizontal dispersion are also lost at narrow gap IDs. We carried out computer simulations by taking the present SPring-8 storage ring and a planned 3GeV low-emittance ring as examples. The results and possible measures for ID protection will be presented.

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THPMF061

Updates on Hardware Developments for SPring-8-II

vacuum, electron, multipole, permanent-magnet

4209

T. Watanabe, S. Takano
Japan Synchrotron Radiation Research Institute (JASRI), RIKEN SPring-8 Center, Hyogo, Japan
H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

We will report the updates on hardware developments for SPring-8-II including a status on a test half-cell construction. A major upgrade of SPring-8, SPring-8-II, targeting substantial improvements in the light source performance is based on a five-bend achromat lattice at an electron energy of 6 GeV*, and hardware accommodating with the new lattice have been extensively developed**. Some of key features are permanent dipole magnets, SUS vacuum chambers, highly accurate and reliable electron and photon beam position monitors, and an extremely small emittance beam injection from the SACLA linac to the storage ring. In the process of the optimization, we cannot rely merely on independent developments; the high packing factor lattice naturally imposes an integration of the individual efforts into a whole design. Thus, a test-half cell has been constructed as one of important milestones, where we need to carefully look through specification balances between different components, physical and magnetic interferences, etc. The presentation will give overall status on the developments as well as the test half-cell construction.
* H. Tanaka et al., Proc. of IPAC2016, Busan, Korea (2016), p.2867. K. Soutome and H. Tanaka, PRAB 20, 064001 (2017).
** e,g, T. Watanabe et al., PRAB 20, 072401 (2017).

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THPMF066

Performance of a Full Scale Superconducting Undulator with 20 mm Period Length at the KIT Synchrotron

undulator, synchrotron, operation, electron

4223

S. Casalbuoni, S. Bauer, E. Blomley, N. Glamann, A.W. Grau, T. Holubek, E. Huttel, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany
C. Boffo, T.A. Gerhard, M. Turenne, W. Walter
Bilfinger Noell GmbH, Wuerzburg, Germany

Within the collaborative effort between KIT and Bilfinger Noell GmbH the development of a full scale superconducting undulator with 20 mm period length (SCU20) has been completed. This device addresses the reliability and reproducibility aspects of the manufacturing process, allowing for the status of a commercial product. The conduction cooled 1.5 m long coils were characterized in the KIT horizontal test facility CASPER II and later assembled in the final cryostat. The system was extensively tested in the final configuration before installation in the KIT storage ring KARA (Karlsruhe Research Accelerator) to be the source of the NANO beamline in December 2017. Here we present the performance of the device.

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THPMF071

Design of a Very Large Acceptance Compact Storage Ring

lattice, laser, electron, sextupole

4239

A.I. Papash, E. Bründermann, A.-S. Müller, R. Ruprecht, M. Schuh
KIT, Eggenstein-Leopoldshafen, Germany

Design of a very large acceptance compact storage ring is underway at the Institute for Beam Physics and Technology of the Karlsruhe Institute of Technology (Germany). Combination of a compact storage ring and a laser wake-field accelerator (LWFA) might be the basis for future compact light sources and advancing user facilities. Meanwhile the post-LWFA beam is not fitted for storage and accumulation in conventional storage rings. New generation rings with adapted features are required. Different geometries and lattices of a ring operating between 50 to 500 MeV energy range were investigated. The model suitable to store the post-LWFA beam with a wide momentum spread (1% to 2%) and ultra-short electron bunches of fs range was chosen as basis for further detailed studies. The DBA-FDF lattice with relaxed settings, split elements and high order optics of tolerable strength allows improving the dynamic aperture up to 20 mm. The momentum acceptance of the compact lattice exceeds 8% while dispersion is limited. The physical program includes turn-by-turn phase compression of a beam, crab cavities, dedicated alpha optics mode of operation, non-linear insertion devices etc.

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THPMF083

Dynamic Simulation for Low Energy Compton Scattering Gamma-Ray Storage Ring

laser, electron, scattering, emittance

4271

Z. Pan, J.M. Byrd, C. Sun
LBNL, Berkeley, USA
H. Hao, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA
W.-H. Huang, C.-X. Tang
TUB, Beijing, People's Republic of China

We have designed a dedicated low-energy electron storage ring to generate gamma-rays based on Compton scattering technique. The natural emittance of the ring is 3.4 nm at 500 MeV beam energy and the ring circumference is about 59 m. The resulting maximum gamma-ray photon energy is about 4 MeV by interacting with ~1 um laser. Due to the large energy loss associated with the gamma-ray photon emission, the electron beam dynamics are greatly affected. We have simulated the whole physics process including Compton scattering, radiation damping and quantum excitation and find that the equilibrium energy spread may be increased by one orders of magnitude depending on the laser parameters. We have studied the dependence of the equilibrium state on the laser intensity and wavelength, and the electron parameters based on our candidate ring lattice.

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THPMK004

Pulse-Picking by Resonant Excitation (PPRE) for Timing Users at the MAX IV 3 GeV Storage Ring

emittance, photon, simulation, cavity

4300

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

At synchrotron light storage rings there is demand for serving both high-brilliance and timing users simultaneously. At many rings this is commonly achieved by operating fill patterns with gaps of sufficient length, but this is not favorable for rings that operate with passive harmonic cavities to damp instabilities and increase Touschek lifetime by lengthening the bunches. For such rings, gaps in the fill pattern could severely reduce the achievable bunch lengths. For the MAX IV 3 GeV storage ring, sufficient bunch lengthening is also essential for conserving the ultralow emittance and reducing heat load on vacuum components at high current. It is therefore of interest to study methods to serve timing users while operating without gap in the fill pattern. Once such method is PPRE, where the transverse emittance of one bunch in the bunch train is increased by an incoherent betatron excitation. This paper presents simulations for the MAX IV 3 GeV storage ring and discusses the machine requirements as well as the achievable performance for timing users.

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THPMK008

Commissioning of the Storage Ring for the Kharkov Generator of X-Ray Radiation NESTOR

electron, MMI, laser, injection

4307

A.A. Shcherbakov, V.P. Androsov, S.V. Bazarov, V.N. Berezka, O. Bezditko, A.V. Cherkashin, A.V. Gevchuk, P. Gladkikh, S.P. Gokov, A.N. Gordienko, V.A. Grevtsev, A. Gvozd, V.E. Ivashchenko, A.A. Kalamayko, I.I. Karnaukhov, I.M. Karnaukhov, V.P. Kozin, V.P. Lyashchenko, V.S. Margin, N.I. Mocheshnikov, M. Moisieienko, A. Mytsykov, F.A. Peev, O.V. Ryezayev, V.P. Sergienko, V.O. Shpagina, N.F. Shul'ga, V. Skomorokhov, D.V. Tarasov, V.I. Trotsenko, V.V. Tsyats'ko, A.Y. Zelinsky, O.P. Zolochevskij, O.D. Zvonarjova
NSC/KIPT, Kharkov, Ukraine
J.I.M. Botman
TUE, Eindhoven, The Netherlands

During 2015-2017 the X-ray source NESTOR (New Electron STOrage Ring) based on a storage ring with low beam energy and Compton scattering of intense laser beam is under commissioning at the National Science Center "Kharkov Institute of Physics and Technology Institute" (NSC KIPT). The start-up of the injector and storage ring is one of the basic task for the facility commissioning. In the paper, the results of the NESTOR X-ray source 225 MeV electron storage ring commissioning are described and further plans are discussed

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THPMK015

Low Momentum Compaction Lattice Operation of the Taiwan Photon Source

lattice, emittance, operation, quadrupole

4325

C.-C. Kuo, C.H. Chen, J.Y. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Huang, C.C. Liang, C.Y. Liao, Y.-C. Liu, Z.K. Liu, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

In order to provide short bunch length for picosecond time-resolved experiments and for coherent IR/THz radiation, low momentum compaction factor (alpha) lattices have been commissioned recently at the Taiwan Photon Source (TPS). The momentum compaction can be positive or negative and its value can be reduced by more than two orders of magnitude. In this paper, we discuss variable low alpha lattice optics, its beam dynamics issues, the measured momentum compaction and bunch lengths as well as beam orbit stability issues, etc.

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THPMK029

Towards an Upgrade of the Swiss Light Source

lattice, emittance, sextupole, injection

4358

A. Streun, M. Aiba, M. Böge, T. Garvey, V. Schlott
PSI, Villigen PSI, Switzerland

An upgrade of the Swiss Light Source (SLS) is planned for the period 2021-24. The existing 12-TBA (triple bend achromat) lattice will be exchanged by a 12-7BA (7-bend achromat) lattice in order to reduce the emittance from present 5.5 nm down to about 125 pm at 2.4 GeV / 400 mA (IBS included). The new lattice is based on longitudinal gradient bends and reverse bends to realize low emittance despite the small circumference of 290 m. A conceptual design has been established. We present project status, lattice design and work in progress with emphasis on beam dynamics issues.

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THPMK071

Lattice Design for a 1.2 GeV Storage Ring

emittance, dipole, lattice, optics

4464

S.Q. Shen, S.Q. Tian, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

It is a very effective way to bring down the emittance of storage ring by using the MBA lattice design. Based on this concept, some other solutions have been developed to reduce the emittance furthermore for recent years. In this paper, the lattice design for a 1.2 GeV storage ring will be presented. The solution of horizontal and longitudinal gradient bending magnets tried in this lattice is going to be discussed in detailed.

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THPMK075

A Possible Scheme for Generating High-harmonic Coherent Radiation in Storage Rings

electron, laser, bunching, radiation

4473

X.F. Wang, C. Feng, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

A possible scheme for storage ring FEL which can introduce small energy dispersion and emittance simultaneously to generate intense coherent light in the storage rings is described. Based on a modiﬁed version of echo-enabled harmonic generation from free-electron lasers, the technique uses a dogleg and a wave-front tilted seed laser, one normal seed laser and two chicanes to make three-dimensional manipulation of the electron beam phase space, producing high-harmonic microbunching of a relativistic electron beam. Due to small energy dispersion and emittance growth, the storage rings do not need long damping time to recover the quality of the electron beams, so this scheme will significantly improve the performance of FELs based on rings. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in Shanghai Synchrotron Radiation Facility.

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THPMK087

Conceptual Design of the RF System for the Storage Ring and Linac of the New Light Source in Thailand

cavity, linac, acceleration, operation

4505

N. Juntong, T. Chanwattana, K. Kittimanapun, T. Pulampong, P. Sunwong
SLRI, Nakhon Ratchasima, Thailand

The new light source facility in Thailand will be a ring-based light source with the circumference of approximately 300m and an electron energy of 3GeV. The target beam emittance is below 1.0 nm·rad with a maximum beam current of 300mA. The injector utilizes a full energy C-band linac with a photocathode RF electron gun. The storage ring RF system is based on a 500MHz frequency. The EU-HOM damped cavity and the new SPring-8 design TM020 cavity is the choice of the storage ring cavity. The RF power unit for storage ring can either be a high-power klystron feeding all RF cavities or a combination of low power IOTs or solid-state amplifiers feeding each cavity. The high gradient C-band structure is considered as the main accelerating structure for linac. The RF power system for linac will base on klystron and a modular modulator. Details of RF systems options for this new light source project will be presented.

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THPMK092

SOLEIL Status Report

operation, synchrotron, controls, undulator

4516

L.S. Nadolski, G. Abeillé, Y.-M. Abiven, P. Alexandre, F. Bouvet, F. Briquez, P. Brunelle, A. Buteau, N. Béchu, M.-E. Couprie, X. Delétoille, T. Didier, J.M. Dubuisson, C. Herbeaux, N. Hubert, C.A. Kitegi, M. Labat, J.-F. Lamarre, P. Lebasque, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, F. Marteau, A. Nadji, R. Nagaoka, P. Prigent, F. Ribeiro, K.T. Tavakoli, M.-A. Tordeux, M. Valléau
SOLEIL, Gif-sur-Yvette, France

SOLEIL is both a synchrotron light source and a research laboratory at the cutting edge of experimental techniques dedicated to matter analysis down to the atomic scale, as well as a service platform open to all scientific and industrial communities. This French 2.75 GeV third generation synchrotron light source provides today extremely stable photon beams to 29 beamlines (BLs) complementary to ESRF. We report facility performance, ongoing projects and recent major achievements. A significant work was performed in order to secure the operation of the two canted 5.5 mm in-vacuum cryogenic permanent magnet undulators (CPMUs). Major R&D areas will also be discussed, and progress towards a lattice baseline for making SOLEIL a diffraction limited storage ring.

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THPMK098

A Tunable Narrowband Source in the Sub-THz and THz Range at DELTA

laser, radiation, electron, detector

4534

C. Mai, B. Büsing, S. Khan, A. Meyer auf der Heide, B. Riemann, B. Sawadski, P. Ungelenk
DELTA, Dortmund, Germany
M. Brosi, J.L. Steinmann
KIT, Karlsruhe, Germany
F. Frei
PSI, Villigen PSI, Switzerland
C. Gerth
DESY, Hamburg, Germany
M. Laabs, N. Neumann
TU Dresden, Dresden, Germany
N.M. Lockmann
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Funding: Work supported by the DFG (INST 212/236-1 FUGG), the BMBF (05K13PEC, 05K16PEB) and the state of NRW.
At DELTA, a 1.5-GeV electron storage ring operated as a synchrotron light source by the TU Dortmund University, an interaction of ultrashort laser pulses with electron bunches is used to generate broadband as well as tunable narrowband radiation in the frequency range between 75 GHz and 5.6 THz. The performance of the source was studied using two different Fourier-transform spectrometers. It was demonstrated that the source can be used for the characterization and comparison of Schottky-diode based detectors, e.g., an on-chip spectrometer enabling single-shot applications.

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THPMK113

From Coherent Harmonic Generation to Steady State Microbunching

bunching, radiation, experiment, electron

4583

X.J. Deng, W.-H. Huang, T. Rui, C.-X. Tang
TUB, Beijing, People's Republic of China
A. Chao, D.F. Ratner
SLAC, Menlo Park, California, USA
J. Feikes, M. Ries
HZB, Berlin, Germany
R. Klein
PTB, Berlin, Germany

Steady state microbunching (SSMB) is an electron storage ring based scheme proposed by Ratner and Chao to generate high average power narrow band coherent radiation with wavelength ranging from THz to EUV. One key step towards opening up the potential of SSMB is the experimental proof of the SSMB principle. In this paper, the SSMB experiment planned and prepared by a recently established collaboration is presented starting from a modified coherent harmonic generation (CHG). Single particle dynamics of microbunching in an electron storage ring are analyzed. Though oriented for CHG and SSMB, some of the effects analyzed are also important in cases like bunch slicing, bunch compression, FEL beam transport lines etc, in which precise longitudinal phase space manipulations are involved. These dynamics together with some SSMB related collective effects are to be investigated on the storage ring MLS in Berlin.

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THPMK120

Hefei Advanced Light Source: A Future Soft X-Ray Diffraction-Limited Storage Ring at NSRL

lattice, emittance, radiation, injection

4598

L. Wang, Z.H. Bai, N. Hu, H.T. Li, W. Li, G. Liu, Y. Lu, Q. Luo, D.R. Xu, W. Xu, P.H. Yang, Z.H. Yang, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

To meet the fast-growing demands for high-quality low-energy photon beams, a new synchrotron radiation light source conception was brought forward several years ago by National Synchrotron Radiation Laboratory, which was named Hefei Advanced Light Source (HALS). The dominant radiation of HALS will be located in the VUV and soft X-ray region, which will be complementary with that of SSRF and HEPS. Except for high brilliance, high transverse coherence will be another signature feature of HALS. To achieve these goals, a multi-bend achromat based diffraction-limited storage ring was adopted as the main body of HALS. The general description and preliminary design of HALS will be briefly presented in this paper. Under the support of the Chinese Academy of Sciences and local government, the preliminary research and development (R&D) for HALS is undergoing. Several key technologies will be developed in the R&D project, which will lay good foundation for the construction of HALS.

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THPMK121

Design of the Second Version of the HALS Storage Ring Lattice

lattice, emittance, dipole, linear-dynamics

4601

Z.H. Bai, W. Li, L. Wang, P.H. Yang, Z.H. Yang
USTC/NSRL, Hefei, Anhui, People's Republic of China

In this paper, a new multi-bend achromat (MBA) lat-tice concept that we recently proposed for diffraction-limited storage rings is described, where two pairs of interleaved dispersion bumps are created in each cell and also most of the nonlinear effects produced by the sextupoles located in these bumps can be cancelled out within one cell. Following this concept, two 7BA lattices have been designed for the Hefei Advanced Light Source storage ring as the second version lattic-es, one with uniform dipoles and the other with nonu-niform dipoles. The latter has a lower natural emit-tance of 23 pm·rad, in which longitudinal gradient bends and anti-bends are employed. The optimized nonlinear dynamics for these two lattices are rather good, and especially the dynamic momentum aperture can be larger than 8% without off-momentum tunes crossing non-structure half-integer resonance lines.

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THPMK125

Development of Non-Evaporable Getter (NEG) Coatings on Small Diameter Vacuum Chambers for Diffraction-Limited Storage Ring

vacuum, site, target, electron

4611

S. Wang, Y.Z. Hong, R. Huang, X.T. Pei, Y. Wang, W. Wei, B. Zhang, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Design of the fourth generation Diffraction-Limited Storage Ring reduces aperture of vacuum chambers to a few centimeters. To satisfy the small aperture, the intense photon bombardment and the requirement of low pressure, most of the beam pipes need to be deposited with Ti-Zr-V nonevaporable getter (NEG) thin films. NEG can provide distributed pumping and low gas desorption and allow to achieve low pressure in narrow and conductance limited chambers. In this paper, Ti-Zr-V thin film was deposited by DC magnetron sputtering using Ti-Zr-V alloy target. The morphology and thickness of Ti-Zr-V are characterized by Scanning Electron Microscopy (SEM). The average grain size is evaluated using X-ray diffraction (XRD). The composition and the corresponding chemical bonding of the thin film are analyzed by X-ray Photoelectron Spectroscopy (XPS). Finally, the adhesion between the film and substrate and the vacuum performance are evaluated.

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THPMK129

Lattice Tweaking Using A Tune Knob Based On Global Mechanism

quadrupole, injection, lattice, simulation

4620

S.W. Wang, B. Li, J.L. Li, W.B. Wu, W. Xu, X. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China
J.L. Li
IHEP, Beijing, People's Republic of China

The transverse tunes are important parameters for a storage ring and tune knobs are used to adjust the tunes in a specific range. Usually for large rings, a set of quadrupoles is set on the straight sections for the use of tune knob. A tune knob has been designed for the HLS-II storage ring without affecting the twiss parameters of the injection section. This paper introduces the design and online test of this tune knob. The quadrupoles are adjusted according to the simulation results and the tunes are measured and calibrated. The online test results show that the tune knob design works well on the HLS-II storage ring and can be applied for various machine studies.

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THPMK130

Study of Beam Instabilities with a Higher-Harmonic Cavity for the HALS

cavity, coupling, HOM, quadrupole

4623

Y.G. Tang, W. Li, Z.B. Sun, L. Wang, C.-F. Wu
USTC/NSRL, Hefei, Anhui, People's Republic of China

Hefei Advanced Light Source (HALS), a diffrac-tion-limited storage ring is on the design. In HALS project, a passive higher-harmonic cavity may be added in order to increase the beam lifetime of the storage ring. When the storage ring is operated with a small momentum compaction, instabilities limit the utility of the high-er-harmonic cavity. In this paper, we run an algorithm (analytic modeling) to consider the Robinson instabilities for normal and superconducting cavity respectively. The Robinson instabilities are predicted with and without mode coupling. Coupled-bunch instability induced by resonant interaction with parasitic longitudinal mode is also considered. The analytic modeling may be used to give rf-cavity parameters that are more conducive to stability. The results show that the storage ring can oper-ate at a higher beam current and the parasitic high-er-order mode of the fundamental cavity has less impact on the beam by using superconducting harmonic cavity.

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THPMK135

Corrector Layout Optimization Using NSGA-II for HALS

closed-orbit, dipole, lattice, sextupole

4629

D.R. Xu, Z.H. Bai, L. Wang, W. Wang, H. Xu
USTC/NSRL, Hefei, Anhui, People's Republic of China

In this paper, we present a method to find the global optimum correctors layout based NSGA-II algorithm when the number of correctors is limited to be equal to the number of BPMs. We prove that this method works well with HALS.

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THPML034

Baseline Lattice for the Upgrade of SOLEIL

emittance, lattice, photon, injection

4726

A. Loulergue, P. Alexandre, P. Brunelle, O. Marcouillé, A. Nadji, L.S. Nadolski, R. Nagaoka, K.T. Tavakoli, M.-A. Tordeux, A. Vivoli
SOLEIL, Gif-sur-Yvette, France
L. Hoummi
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Previous MBA studies converged to a lattice composed of 7BA-6BA with a natural emittance value of 200- 250 pm.rad range. Due to the difficulties of non-linear optimization in targeting lower emittance values, a decision was made to symmetrize totally the ring with 20 identical cells having long free straight sections longer than 4 m. A 7BA solution elaborated by adopting the sextupole paring scheme with dispersion bumps originally developed at the ESRF-EBS, including reverse-bends, enabling an emittance of 72 pm.rad has been defined as the baseline lattice. The sufficient on-momentum dynamic aperture obtained allows to consider off-axis injection. The linear and nonlinear dynamic properties of the lattice along with the expected performance in terms of brilliance and transverse coherence are presented. In particular, the beta functions tuned down to 1 m in both transverse planes at the center of straight sections allow matching diffraction limited photons up to 3 keV.

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THPML066

Filling Pattern Measurement System Upgrade in SSRF*

operation, SRF, synchrotron, injection

4791

N. Zhang, F.Z. Chen, Y.M. Zhou
SSRF, Shanghai, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (No.11575282 No.11375255 No.11305253)
Filling pattern affects various operation performance of a synchrotron light source. A new diagnostic beam charge monitor (BCM) with high bandwidth multi-channels digitizer was developed to perform bunch-by-bunch charge measurement and record filling pattern for SSRF storage ring. Signals picked up from button elec-trodes were sampled synchronously with RF frequency, and IQ (In-phase and Quadrature phase) sampling meth-od was employed for noise-filtering and phase independ-ence calibration. Layout and evaluation experiment of the system are presented in this paper.

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THPML068

Upgrade of Bunch Phase Monitor at SSRF Storage Ring

injection, SRF, pick-up, experiment

4797

Y.M. Zhou, Y.B. Leng, T. Wu, N. Zhang
SSRF, Shanghai, People's Republic of China

Beam instability is a serious problem for physics in beam diagnosis technology. With regard to the evaluation of longitudinal phase oscillations during the transient injection process, bunch-by-bunch phase measurement is a useful tool for studying the behavior of the refilled bunches. A new upgraded beam phase monitor system with 1.2GHz bandwidth PXI waveform digitizer has been developed at Shanghai synchrotron radiation source (SSRF). Bunch-by-bunch phase information, retrieved from button pickup signals, is calculated by the zero-crossing detection method with the best phase resolution of 0.4ps. The refilled bunches can be separated from the stored ones, and the longitudinal offset of each refilled bunch has been measured. Several groups of experiments have been performed to verify the repeatability of bunch-by-bunch phase measurement, and some results regarding refilled bunches will be discussed in this paper.

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THPML072

Injection Comparison using Bunch-by-Bunch Beam Size Measurement System at SSRF

injection, damping, SRF, betatron

4811

H.J. Chen, J. Chen, B. Gao, Y.B. Leng
SINAP, Shanghai, People's Republic of China

Injection transient process happens every 5-10 minutes in storage ring during normal top-up operating mode at SSRF, which is a proper window for machine status and injection performance evaluation. In the recent year, a bunch-by-bunch beam size measurement system has been implemented at SSRF, which has the capability to offer transverse bunch-by-bunch position and size information and is a powerful tool for injection study. In this paper, we summarize three injection study results from July 2017 to April 2018, including betatron oscillation amplitude, spectrum, horizontal tune and damping time comparison. The oscillation amplitude and temporal behavior of recent injection are all better than results before contributed to the injection optimization work during maintenance in 2018 winter. In addition, the principal component analysis method is also applied to further study the injection behavior in turn-by-turn or bunch-by-bunch direction to the refilled bucket.

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THPML084

Validating the COBEA Algorithm at the DELTA Storage Ring

optics, betatron, closed-orbit, lattice

4851

B. Riemann, B.D. Isbarn, S. Khan, S. Koetter, T. Weis
DELTA, Dortmund, Germany

Closed-Orbit Bilinear-Exponential Analysis (COBEA) is an algorithm to decompose monitor-corrector response matrices into (scaled) beta optics values, phase advances, scaled dispersion and betatron tunes. No explicit magnetic lattice model is required for COBEA - only the sequence of monitors and correctors along the beam path (no lengths, no strengths approach). To obtain absolute beta values, the length of one drift space can be provided as optional input. In this work, the application of COBEA to the DELTA storage ring, operated by TU Dortmund University, is discussed, and its results for betatron tunes and scaled dispersion are compared with those of conventional, direct measurement methods. COBEA is also put in a historical perspective to other diagnostic algorithms. Improvements in the Python implementation of COBEA, which is available as free software, are presented. Due to COBEA being relatively modest regarding its requirements on input data respectively hardware, it should be applicable to the majority of existing storage rings.

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THPML085

Intelligent Controls for the Electron Storage Ring DELTA

controls, network, electron, synchrotron

4855

D. Schirmer
DELTA, Dortmund, Germany

In recent years, artificial intelligence has become one of the buzzwords in the field of controlling, monitoring and optimizing complex machines. Particle accelerators belong to this class of machines in particular. In accelerator controls one has to deal with a variety of time-varying parameters, nonlinear dynamics as well as a lot of small, compounding errors. Therefore, to cope with these tasks and to achieve higher performance, particle accelerators require new advanced strategies in controls and feedback systems. Machine learning through (deep) neural networks, genetic algorithms, swarm intelligence and adaptive controls are some of the proposed approaches. Increased computational capability and the availability of large data sets in combination with better theoretical understanding of new network architectures and training paradigms allow for promising approaches for novel developments. This report aims to discuss the state of the art techniques and presents ideas for possible applications of intelligent controls at the synchrotron radiation source DELTA.

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THPML111

Test of the Tune Measurement System Based on BBQ at HLS-II Storage Ring

betatron, ion-source, experiment, controls

4926

L.T. Huang, F.L. Gao, P. Lu, B.G. Sun, H.Q. Wang, J.G. Wang, Q. Wang, F.F. Wu, Y.L. Yang, T.Y. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by the National Science Foundation of China (Grant No. 11705203, 11575181)
The HLS-II storage ring is a crucial part of Hefei Light Source. Tune is one of the most important parameters of the electron storage ring, of which the tune measurement system is an integral component. In this paper, the design of a new tune measurement system based on BBQ (base band tune), is presented. Some experiments are performed to test this system. The new system is compared with the original system and the TBT (turn-by-turn) method respectively. The obtained results illustrate higher accuracy and higher stability for the new system. A new approach of calculating the betatron oscillation amplitude is proposed, and the betatron oscillation amplitudes in the normal running stage for the HLS-II storage ring are estimated at 95 nm (horizontal) and 60 nm (vertical).

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THPML112

Preliminary Design and Calculation of Button BPM for the HALS Storage Ring

vacuum, HOM, electronics, impedance

4929

F.F. Wu, F.L. Gao, L.T. Huang, X.Y. Liu, P. Lu, B.G. Sun, J.H. Wei, Y.L. Yang, T.Y. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China
L. Lin
Huizhou University, Huizhou, People's Republic of China

Funding: Supported by the National Science Foundation of China (Grant No.11705203, 11575181，11605202) and the National Key Research and Development Program of China(No. 2016YFA0402000)
Button BPM is being designed for the HALS storage ring, which is a diffraction-limited storage ring (DLSR) located at the NSRL in Hefei city. Since beam size is very small, the required resolution of 50 nm for beam position measurement need to be obtained. The parameters of the HALS Button BPM are initially determined. According to theoretical formulas, electrode induced signal is calculated and the relationship between electrode induced signal and beam current is obtained. Signal to noise ratio(SNR)of the HALS Button BPM is calculated with different beam current when the required resolution is 50 nm. The results show that the SNR is well when beam current is very low. In addition, the effects of BPM RF frequency and button electrode radius on SNR are analyzed.

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THPML124

Design of Beam Position Fast-Correction Magnet Power Supply for HALS

controls, power-supply, feedback, operation

4967

Z.X. Shao, H. Gao, L. Wang, H.Y. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by 'Hefei Advanced Light Source Pre-research Project'
Hefei Advanced Light Source (HALS) is the fourth-generation radiation light source that is being pre-researched in China. Ultra-low emittance of the beam requires higher performance of power supply system. We designed a fast correcting power supply for the beam measurement needs. We adopted the all-digital method, the current closed-loop feedback used the AD7766 with 24-bit resolution as its A/D converter. And we added the corresponding constant temperature control, chain protection, etc. The small-signal frequency response of this system can reach more than 5kHz. The detail design scheme is described in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML124

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THPML129

Deposition and Characterization of TiZrHfV films by DC Magnetron Sputtering

vacuum, electron, controls, target

4983

X.Q. Ge, T.L. He, X.T. Pei, Y.G. Wang, Y. Wang, W. Wei, B. Zhang, Y.X. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

The new generation of accelerators places higher demands on the surfaces of vacuum chamber materials. Search for low secondary electron yield (SEY) materials and an effective vacuum chamber surface treatment process, which can effectively reduce the electronic cloud effect, are important early works for the new generation of accelerators. In this work, we revealed the SEY characteristics of Ti-Zr-Hf-V NEG films and Ti-Zr-V NEG films which were deposited on Si (111) substrates using direct current magnetron sputtering method. The surface morphology and surface chemical bonding information were collected by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). With the same parameters, the maximum SEY of Ti-Zr-Hf-V NEG films and Ti-Zr-V NEG films are 1.24 and 1.51, respectively. These results are of great significance for the next-generation particle accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML129

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THPML130

Applications of a Distributed Beam Loss Monitor at the Australian Synchrotron

synchrotron, target, detector, injection

4986

P.J. Giansiracusa, T.G. Lucas, R.P. Rassool, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
M.J. Boland
CLS, Saskatoon, Saskatchewan, Canada
G. LeBlanc
SLSA, Clayton, Australia

A distributed beam loss monitoring system, based on Cherenkov silica fibres, has been installed at the Australian Synchrotron. The fibres are installed parallel to the beam pipe and cover the majority of the injection system and storage ring. Relativistic charged particles from beam loss events that have a velocity above the Cherenkov threshold produce photons in the fibres. These photons are then guided along the fibres to detectors outside of the accelerator tunnels. Originally the system was installed to determine its suitability for measuring losses at a future linear collider, such as the Compact Linear Collider, with single pass 150 ns bunch trains. This study builds on these results and attempts to use the system to measure loss locations with a circulating beam. We present the preliminary results and describe how the system could be improved.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML130

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THPML135

Design of the Combined Function Dipole-Quadrupoles (DQS) with High Gradients

quadrupole, dipole, vacuum, lattice

5001

Z.L. Ren, C. Chen, T.L. He, L. Wang, X.Q. Wang, H. Xu, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by the National Nature Science Foundation of China under Grant Nos.11375176 * hlxu@ustc.edu.cn **zhbo@ustc.edu.cn
Combined dipole-quadrupoles (DQs) can be obtained with the design of tapered dipole or offset quadrupole. However, the tapered dipole design can not achieve a high gradient field, as it will lead to poor field quality in the low field area of the magnet bore, and the design of offset quadrupole will increase the magnet size and power consumption. Finally, the dipole-quadrupole design developed is between the offset quadrupole and septum quadrupole types. The dimensions of the poles and the coils of the low field side have been reduced. The 2D pole profile is simulated and optimized by using POSSION and Radia, while the 3D modle using Radia and OPERA-3D. The end shimming and chamfer are modelled to meet the field uniformity requirement.

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THPML138

Efficiency and Error Analysis of the HALS Injection Scheme

injection, simulation, kicker, lattice

5008

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

Hefei Advanced Light Source (HALS) is a newly designed diffraction-limited storage ring.. The latest version of HALS has a 7BA lattice. One of the most important parts about HALS design is its injection system. Since conventional injection scheme is not suitable for DLSRs, many new injection schemes are proposed, including longitudinal injection scheme. In this paper, we investigate the feasibility of longitudinal injection scheme for HALS. In order to evaluate the injection performance, various errors have been considered. A series of tracking simulations are carried out and injection efficiency is obtained under different error levels.

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THPML140

Radiation Monitoring System of HLSII

radiation, monitoring, operation, detector

5011

Lin, H.S. Lin, Y.Q. Cai, S.P. Jiang, Z.B. Sun, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by the National Science Foundation of China 11675170 By the Fundamental Research Funds for the Central Universities WK2310000056
Monitoring of ionizing radiation of synchrotron radiation facility is very important for the safety of staff and users of the light source. Radiation monitoring system of HLSII has been built and the whole system consists of local radiation monitoring spots and central control system, and a web-based monitoring dynamic release system. The local radiation monitoring spot consists of a high air pressure ionization type gamma detector and a BF3 counting tube neutron detector, and the radiation data are calculated by microcontroller locally and acquired by the data server for further processing. The dynamic release system is integrated with EPICS interface and radiation safety interlock system. Other accelerator systems could obtain radiation data from the server and the interlock system is triggered by the radiation data to shut down the machine in case the radiation exceeds the safety threshold.

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FRXGBD4

Observation of Saw-Tooth Effect Orbit in the VEPP-4 M Collider

electron, positron, experiment, collider

5026

Leshenok D. Leshenok, E.A. Bekhtenev
NSU, Novosibirsk, Russia
E.A. Bekhtenev, G.V. Karpov, S.A. Nikitin, O.A. Plotnikova
BINP SB RAS, Novosibirsk, Russia

We study the relative position of the electron and posi-tron closed orbits in the VEPP-4M single storage ring collider in experiments on orbit precision monitoring. A difference in the orbits can affect the accuracy of several fundamental experiments, e.g. precise comparison of the electron and positron spin frequencies (the CPT invari-ance test) [1]. In this case, the spin precession frequencies of particles should be compared within at least 5·10^-9. The distinction of frequencies depends on the features of the radial orbits. Ideally, the difference in the electron and positron orbits is set only by distributed radiation losses of particle energy. The corresponding contribution to the total orbit distortions is called the Saw-Tooth effect orbit. Another example of possible precision experiment at VEPP-4M is search for the light speed anisotropy (LSA). In this case, it is necessary to ensure a stability of the difference in the radial orbits of electrons and positrons at a level of 1μm.

Slides FRXGBD4 [1.602 MB]

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FRXGBE2

Muon Beam Dynamics and Spin Dynamics in the g-2 Storage Ring

quadrupole, injection, positron, experiment

5029

D. L. Rubin, A.T. Chapelain
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
S. Charity, J. Price
The University of Liverpool, Liverpool, United Kingdom
J.D. Crnkovic, W. Morse, V. Tishchenko
BNL, Upton, Long Island, New York, USA
F.E. Gray
Regis University, Denver, USA
J. E. Mott
BUphy, Boston, Massachusetts, USA
W. Wu
UMiss, University, Mississippi, USA

Funding: This work was supported in part by the U.S. Department of Energy DOE HEP DE-SC0008037
The goal of the new g-2 experiment at fermilab is a measurement of the anomalous magnetic moment of the muon, with uncertainty of less than 140 ppb. The experimental method is to store a beam of polarized muons in a storage ring with pure vertical dipole field and electrostatic focusing, and to measure the precession frequency. Control of the systematics depends on unprecedented knowledge of the details of the phase space of the muon distribution. That knowledge is derived from direct measurements with scintillating fiber detectors that are inserted into the muon beam for diagnostic measurements, traceback straw tube tracking chambers, as well as the calorimeters that measure energy, time and position of the decay positrons. The interpretation of the measurements depends on a detailed model of the storage ring guide field. This invited talk presents results of studies of the distribution from the commissioning run of the experiment.

Slides FRXGBE2 [12.809 MB]

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