IPAC2016 - Classification: 05 Beam Dynamics and Electromagnetic Fields / D02 Non-linear Single Particle Dynamics - Resonances, Tracking, Higher Order, Dynamic Aperture, Code

Paper	Title	Page
MOZA02	Design and Optimization Strategies of Nonlinear Dynamics in Diffraction-limited Synchrotron Light Sources	33
	R. Bartolini DLS, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	This talk introduces the most recent achievements in the control of nonlinear dynamics in electron synchrotron light sources, with special attention to diffraction limited storage rings. Guidelines for the design and optimization of the magnetic lattice are reviewed and discussed.
	Slides MOZA02 [4.952 MB]
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THOBA01	RF Pinger Commissioning and Beam Dynamics Studies at NSLS-II	3161
	G.M. Wang, B. Holub, Y. Li, J. Rose, T.V. Shaftan, V.V. Smaluk BNL, Upton, Long Island, New York, USA
	Funding: DOE contract DE-SC0012704 NSLS II storage ring RF system has the digital ramp control function, enabling rapid change of the cavity phase and amplitude. This, together with largely overcoupled RF cavity and transmitter geometry, enables the possibility to "ping" the beam in longitudinal phase space. Similar to the pinger commonly used for transverse beam dynamic studies, the RF jump presents with a powerful tool for investigation of the machine longitudinal beam dynamics. During our beam studies, RF phase was jumped within a short interval of time (less than synchrotron period). Using turn-by-turn data from BPMs we measured the machine energy acceptance with and without damping wigglers. This paper presents the beam study results.
	Slides THOBA01 [4.365 MB]
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THPMB019	Comparing the Performance of MOGA and MOPSO in Optimization of the HEPS Performance	3266
	Y. Jiao, G. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS), a kilometre- scale diffraction-limited storage ring light source, with a beam energy of 5 to 6 GeV and emittances of a few tens of pm.rad, is to be built in Beijing. A preliminary design with a hybrid 7BA lattice, an emittance of 60 pm.rad and a circumference of about 1.3 kilometers, has been made. Based on this design, we optimized the linear and nonlinear performance of the ring with the MOGA and MOPSO algorithms. From comparison of the performance of these two algorithms, it was found that MOPSO promises higher diversity than MOGA, while MOGA can reach better convergence than MOPSO. To reach a true Pareto front, a successive and iterative implementation of the PSO and MOGA, rather than using either of these two algorithms, is suggested.
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THPMR006	Muon Beam Tracking and Spin-Orbit Correlations for Precision g-2 Measurements	3397
	D. Tarazona, M. Berz, R. Hipple, K. Makino, M.J. Syphers MSU, East Lansing, Michigan, USA M.J. Syphers Fermilab, Batavia, Illinois, USA
	The main goal of the Muon g-2 Experiment (g-2) at Fermilab is to measure the muon anomalous magnetic moment to unprecedented precision. This new measurement will allow to test the completeness of the Standard Model (SM) and to validate other theoretical models beyond the SM. The close interplay of the understanding of particle beam dynamics and the preparation of the beam properties with the experimental measurement is tantamount to the reduction of systematic errors in the determination of the muon anomalous magnetic moment. We describe progress in developing detailed calculations and modeling of the muon beam delivery system in order to obtain a better understanding of spin-orbit correlations, nonlinearities, and more realistic aspects that contribute to the systematic errors of the g-2 measurement. Our simulation is meant to provide statistical studies of error effects and quick analyses of running conditions for when g-2 is taking beam, among others. We are using COSY, a differential algebra solver developed at Michigan State University that will also serve as an alternative to compare results obtained by other simulation teams of the g-2 Collaboration.
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THPMR011	Injection Dynamics for Sirius Using a Nonlinear Kicker	3406
	L. Liu, X.R. Resende, A.R.D. Rodrigues, F. H. de Sá LNLS, Campinas, Brazil
	The concept of injection using a single nonlinear kicker has been proposed and tested in several existing storage rings with reduction in the stored beam oscillations during the accumulation process. Despite the good results, this scheme has not yet been adopted for routine operation in these machines due to the reduced injection efficiency. The main cause for reduction in efficiency is precisely the nonlinearity of the kick at the injected beam position and the generally large injected beam size. In this paper we study the injection dynamics in the Sirius storage ring where beam accumulation is based only on the use of a nonlinear kicker. The whole injection system has been optimized from the start for high injection efficiency.
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THPMR012	Optimization of Nonlinear Dynamics for Sirius	3409
	F. H. de Sá, L. Liu, X.R. Resende LNLS, Campinas, Brazil
	In this work we describe the optimization of the non-linear dynamics for the Sirius storage ring. The strong sextupoles of the lattice, necessary to correct the linear chromaticities, generate higher order terms in the tune-shifts with amplitude and energy, which may result in a large tune footprint for the machine. The configuration the sextupole families found that wraps this tune footprint and thus avoids dangerous resonances was achieved with minimization of Hamiltonian driving terms and tracking-based multi-objective algorithms include realistic values of misalignment and excitation errors of the magnets, orbit correction, insertion devices fields and real vacuum chamber apertures.
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THPMR014	Core-halo Limits and Beam Halo-formation Dynamic	3417
	M. Valette, P.A.P. Nghiem CEA/IRFU, Gif-sur-Yvette, France N. Pichoff CEA/DSM/IRFU, France
	In high intensity linear accelerators, space charge related instabilities and effects are the cause of emittance increase and beam losses. The mechanism of halo formation due to a mismatched beam causing parametric resonances and energy transfer between phase-spaces is one of them. The previously defined one dimensional core-halo limit [1][2] was extended to two dimensional distributions [3][4]. This halo characterization method is applied to a classical case of transport for halo formation studies: the transport of a mismatched beam. Our method provides a core-halo limit that matches the expected halo formation mechanism with a very good precision. * Appl. Phys. Lett. 104, 074109 (2014) Phys. Plasmas, 22, 083115, (2015) * IPAC (2015) MOPWA010 **** TBP
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THPMR015	RCDS Optimizations for the ESRF Storage Ring	3420
	S.M. Liuzzo, N. Carmignani, L. Farvacque, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	The Robust Conjugate Direction Search (RCDS)* optimizer is applied for online optimizations of the ESRF accelerators. This paper presents the successful application of the algorithm in reducing vertical emittance, improving injection efficiency and increasing lifetime. A new set of sextupole settings to increase chromaticity has been obtained with lifetimes comparable to the existing one. This allows to run with double current in a single bunch, and unifies the optics for few bunch (except 4x10 bunches) and multi-bunch modes. * X. Huang, J. Corbett, J. Safranek, J. Wu, "An algorithm for online optimization of accelerators", Nucl. Instr. Methods, A 726 (2013) 77-83.
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THPMR017	Resonance Island Experiments at BESSY II for User Applications	3427
	P. Goslawski, J. Feikes, K. Holldack, A. Jankowiak, M. Ries, M. Ruprecht, A. Schälicke, G. Wüstefeld HZB, Berlin, Germany R. Ovsyannikov BESSY GmbH, Berlin, Germany
	Beam storage close to a tune resonance (Qx = 1/3, 1/4) can generate resonance island buckets in the x,x' phase space providing a second stable island orbit winding around the standard orbit. Experiments with such an operation mode have been conducted at BESSY II and the Metrology Light Source (MLS),. The two orbits are well separated, with good life time and stability. Such operation mode will offer additional operation flexibility and allows users to choose their radiation source point from one or the other orbit. It has the potential to fulfill simultaneously conflicting user demands, e.g., high vs. low beam current and single or few bunch filling vs. multibunch filling. We discuss the required beam optics setup and present successful measurements taken at photon beamlines at BESSY II. P. Goslawski et al., "Bunch Separation by Transverse Resonance Island Buckets", ESLS XXIII Workshop, 2015, Villigen, Switzerland. ** M. Ries et al., Proc. IPAC 2015, Richmond, USA, MOPWA021.
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THPMR018	Ion-Optics of Antiproton Separator at FAIR	3431
	S.A. Litvinov, A. Dolinskyy, K. Knie GSI, Darmstadt, Germany I. Koop, P.Yu. Shatunov, I.M. Zemlyansky BINP SB RAS, Novosibirsk, Russia
	In the framework of antiproton program at FAIR project, the large acceptance antiproton separator is dedicated for the effective separation of the secondary antiprotons from the primary protons and the secondary beams of other particle species and subsequent transportation to the Collector Ring (CR). Here we present the latest ion-optical layout of the antiproton separator and possible second-order correction scheme as well.
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THPMR020	Bunch Purity Measurements at PETRA III	3434
	J. Keil, H. Ehrlichmann DESY, Hamburg, Germany
	Since 2010 the 6 GeV synchrotron light source PETRA III is in operation. With a horizontal emittance of 1.2 nm*rad, a coupling of typically 1% and a total beam current of 100 mA the machine provides extremely brilliant synchrotron radiation for the users. For time-resolved measurements a filling pattern with 40 equidistant bunches with equal charge is used. To measure parasitic bunches between the main bunches two beamlines are equipped with avalanche photodiodes (APD) and time to digital converters (TDC) electronics. Besides parasitic bunches originating from the pre-accelerators of PETRA III it has been observed that initially empty buckets following the main bunch are populated. Measurements of the effect will be discussed and compared with simulations.
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THPMR021	Bmad Model of COSY, Status and Progress	3437
	Y. Dutheil FZJ, Jülich, Germany
	Abstract The COSY in Jülich is a versatile machine with a long history of polarized proton acceleration. A new model of COSY based on the Bmad library was developed to simulate beam and spin dynamics. Original methods of lattice design, notably multi-objective lattice optimization, were explored. This contribution presents the status and development steps of the Bmad model of COSY. Some of the latest simulations will also be discussed.
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THPMR022	Non-linear Optimization of Storage Ring Lattice for the SPring-8 Upgrade	3440
	K. Soutome, K.K. Kaneki, Y. Shimosaki, M. Takao JASRI/SPring-8, Hyogo-ken, Japan H. Tanaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	A project of upgrading the SPring-8 facility is ongoing to convert the present storage ring to a high-coherence hard X-ray source (SPring-8-II). To achieve the emittance value of less than 0.2 nmrad at 6 GeV, we adopted a 5-bend achromat lattice with dipoles having longitudinal field gradient. In this lattice the betatron phase between the two dispersion arcs was set to (2n+1)PI to suppress dominant harmful effects of chromaticity-correcting sextupoles. By detuning this phase, optimizing sextupole strengths in a cell and introducing octupoles, we obtained a sufficient dynamic aperture (DA) for beam injection even for the symmetry-broken ring having four long straight sections and a high-beta injection section. However, the off-momentum behavior such as the non-linear chromaticity still needs to be optimized to achieve the momentum acceptance (MA) of 3% or larger. We have thus been investigating the possibility to increase both the DA and MA by introducing several phase-matched sextupole pairs. The presentation will report the obtained results by this approach.
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THPMR025	Simulation of Beam Behavior Caused by Odd Harmonics of Beam Loading in J-PARC RCS	3443
	M. Yamamoto, M. Nomura, T. Shimada, F. Tamura JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan K. Hara, K. Hasegawa, C. Ohmori, M. Toda, M. Yoshii KEK, Tokai, Ibaraki, Japan
	The J-PARC RCS accelerates 2 bunches at the harmonic number 2. The major Fourier component of the beam current is even harmonics. However, the odd harmonics grow under some conditions even though they are very small amplitude at the beginning. We describe the the particle tracking simulation results for the odd harmonic beam loading effect in the RCS.
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THPMR026	SESAME Storage Ring Beam Dynamics in View of the Results of its Magnet Measurements	3446
	M. Attal, E. Huttel SESAME, Allan, Jordan
	SESAME storage ring magnets have been recently constructed and measured. The storage ring beam dynamics is reviewed in this article in view of these results. Moreover it is shown how the optical impact of dipoles main field errors is more mitigated by sorting dipoles in the storage ring in addition to the alignment optimization method suggested by magnetic measurement outcome.
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THPMR030	Results of the Use of Axisymmetric RF Focusing in Proton Linacs at Energies up to 7 MeV	3449
	V.S. Dyubkov, Ya.V. Shashkov MEPhI, Moscow, Russia
	During a few decades axisymmetric RF structures with a focusing by means of nonsynchronous spatial harmonics of electromagnetic field are offered instead of proven RFQ. An effectiveness of these structures in the energy range up to 2 MeV was shown in a number of papers. An effectiveness of these structures in the energy range up to 7 MeV is considered in this paper. Results of an analytical investigation and a numerical simulation of self-consistent proton dynamics are presented and discussed.
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THPMR031	Turn-by-Turn Measurements for Beam Dynamics at Vepp-5 Damping Ring	3452
	M.F. Blinov, K.V. Astrelina, V.V. Balakin, O.I. Meshkov, A.A. Starostenko BINP SB RAS, Novosibirsk, Russia V.L. Dorokhov BINP, Novosibirsk, Russia
	Preinjector complex VEPP-5 is being constructed for high rate production and acceleration of electrons and positrons beams up to energy 510 MeV. Both kinds of particles accumulated in the damping ring and after achieving of needed intensity the beams would be transported alternatively to VEPP-3/VEPP-4M or to BEP/VEPP-2000 colliders. At this paper basic parameters of damping ring presented. All measurements were carried out for electron beam with energy 385 MeV. For turn-by-turn measurements 12 beam position monitors were used. In order to improve precision of measured value NAFF algorithm was applied. For measurements of longitudinal beam profile optical phi-dissector was used.
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THPMR032	Dynamical Aperture Control in Accelerator Lattices With Multipole Potentials	3455
	I.A. Morozov, E.B. Levichev BINP SB RAS, Novosibirsk, Russia
	We apply two analytical methods to control accelerator dynamic aperture (DA) with multipole potentials. Both methods assume that accelerator model can be represented as a product of unperturbed and perturbed exponential operators with exponent of perturbed operator given as formal power series in perturbation parameter and known dependence of series coefficients on lattice parameters such as multipole strength distribution. Normal form method can be applied to the above representation and then lattice parameters are used to control normal form Hamiltonian coefficients. Hamiltonian control can be used to compute control term and lattice parameters are then fitted to approximate corresponding controlled operator. Theoretical results as well as model examples are presented.
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THPMR034	Simulation of Single Particle Dynamics in a Compact Planar Wiggler	3458
	D.A. Shkitov, A.E. Harisova, Y.N. Sutygina TPU, Tomsk, Russia
	In this report a description of a simple approach how to simulate a single particle track in a 3D magnetic field using Radia code is presented. Such a simulation maybe useful in order to briefly estimate in a short time the beam dynamics in the magnetic field produced by means of different types of the magnet devices. As an example, a low energy relativistic electron tracking* is performed in a compact 30 cm planar wiggler which produced ~0.4 T magnetic field. The changes of the electron entrance point and motion direction are also available. This simulation is carried out using three-dimensional magnetostatic code - Radia*, where the 4th order Runge-Kutta method was implemented for the trajectory calculations. Since Radia is the Mathematica add-on then a small Wolfram Language code is developed to create the wiggler model, to calculate the electron trajectory and to illustrate the simulation results. Knyazik A. et al. Status of UCLA helical permanent-magnet undulator // Proc. of PAC, Canada, WE5RFP076 (2009) 2441 ** http://www.esrf.eu/Accelerators/Groups/InsertionDevices/Software/Radia
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THPMR035	Low Horizontal Beta Optics for ALBA	3461
	G. Benedetti, J. Campmany, Z. Martí ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	The ALBA insertion device beamlines have a horizontal and vertical rms source size of 130 and 5.5 microns. Protein crystallography beamlines (Xaloc) would benefit from a reduction of the horizontal and increase of the vertical beam size, to gain spatial resolution and avoid anisotropy effects. A modified lattice with horizontal and vertical beam size of 74 and 9 microns has been setup and tested, breaking the ring symmetry, with different setting of the six neightbouring quadrupoles at each side of the Xaloc insertion device. Such configuration keeps the nominal emittance almost unvaried and the working point is recovered by small changes in the quadrupole strengths of the four symmetric matching sections. A dedicated setting of the nine available sextupole families has been obtained by numerical optimization of the dynamical apertures and tune shifts. The lattice settings have been satisfactorily tested. The measured lifetime is reduced a factor two and the injection efficiency decreases to 60%. Finally, the option of increasing the number of sextupole families, to recover the dynamic aperture and guarantee the injection efficiency, has been studied.
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THPMR036	Improved Methods for the Measurement and Simulation of the CERN SPS Non-linear Optics	3464
	H. Bartosik, A. Oeftiger, M. Schenk, F. Schmidt, M. Titze CERN, Geneva, Switzerland
	Good knowledge of the non-linear properties of the SPS lattice is crucial for modelling and optimising the machine performance in the presence of collective effects leading to incoherent tune spreads such as space charge, e-cloud and beam coupling impedance. In view of the LHC injectors upgrade (LIU) project and the future SPS operation in a regime dominated by such collective effects, detailed measurements of the SPS non-linear chromaticity and detuning with amplitude have been performed for the two optics configurations presently available for LHC type beams. The measurement results are used to fit systematic multipole components to the main magnets of the SPS MADX model as a basis for the non-linear machine model that can be used for beam dynamics simulations. The implications for the operation of the SPS with the LIU beam parameters are discussed.
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THPMR037	Observations of Resonance Driving Terms in the LHC during Runs I and II	3468
	F.S. Carlier, J.M. Coello de Portugal, E.H. Maclean, T. Persson, R. Tomás CERN, Geneva, Switzerland
	Future operations of the LHC will require a good understanding of the nonlinear beam dynamics. In 2012, turn-by-turn measurements of large diagonal betatron excitations in LHC Beam 2 were taken at injection energy. Spectral analysis of these measurements shows an anomalous octupolar spectral line at frequency -Qx-2Qy in the horizontal motion. The presence of this spectral line, as well as other lines, was confirmed by measurements taken for LHC Beam 1 and Beam 2 during the commissioning in 2015. We take a close look at the various spectral lines appearing in the LHC transverse motion in order to improve the LHC nonlinear model.
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THPMR038	Non-Linear Errors in the Experimental Insertions of the LHC	3472
	E.H. Maclean, F.S. Carlier, M. Giovannozzi, A. Langner, S. Mönig, T. Persson, P.K. Skowroński, R. Tomás CERN, Geneva, Switzerland
	Correction of nonlinear magnetic errors in low-β insertions can be of critical significance for the operation of a collider. This is expected to be of particular relevance to LHC Run II and the HL-LHC upgrade, as well as to future colliders such as the FCC. Current correction strategies for these accelerators have assumed it will be possible to calculate optimized local corrections through the insertions using a magnetic model of the errors. To test this assumption the nonlinear errors in the LHC experimental insertions have been examined via feed-down and amplitude detuning. It will be shown that while in some cases the magnetic measurements provide a sufficient description of the errors, in others large discrepancies exist which will require beam-based correction techniques.
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THPMR039	Commissioning of Non-linear Optics in the LHC at Injection Energy	3476
	E.H. Maclean, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, A. Langner, L. Malina, T. Persson, P.K. Skowroński, R. Tomás CERN, Geneva, Switzerland
	Commissioning of the nonlinear optics at injection in the LHC was carried out for the first time in 2015 via beam-based methods. Building upon studies performed during Run I, corrections to the nonlinear chromaticity and detuning with amplitude were obtained. These corrections were observed to reduce beam-loss during measurement of linear optics.
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THPMR041	Implementation of High Order Symplectic Integrators with Positive Steps in Tracking Programs	3484
	K. Skoufaris, Y. Papaphilippou CERN, Geneva, Switzerland J. Laskar IMCCE, Paris, France Ch. Skokos University of Cape Town, Cape Town, South Africa
	The symplectic integrators CSABAν & CSBABν are used in order to calculate single particles dynamics in accelerators and storage rings. These integrators present only positive steps and can be accurate up to the high order. They are compared with already existing splitting methods of MAD-X with respect to their impact on various beam dynamics quantities, for different beam elements.
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THPMR043	Performance of Transverse Beam Splitting and Extraction at the CERN Proton Synchrotron in the Framework of Multi-turn Extraction	3492
	G. Sterbini, J.C.C.M. Borburgh, S. Damjanovic, S.S. Gilardoni, M. Giovannozzi, C. Hernalsteens, M. Hourican, A. Huschauer, K. Kahle, G. Le Godec, O. Michels CERN, Geneva, Switzerland C. Hernalsteens EPFL, Lausanne, Switzerland
	Considerable progress has been made in 2015 in the setting up of the multi-turn extraction (MTE) in the CERN Proton Synchrotron (PS). A key ingredient in this novel extraction technique is the beam splitting in transverse phase space. This manipulation is based on adiabatic trapping in stable islands of transverse phase space and requires mastering a number of devices in the PS ring. In addition, an in-depth review of all fast extractions schemes in the PS had been required due to the development and installation of a dummy septum to shield the actual magnetic septum. In this paper, the current performance of the beam splitting and of the extraction including the shadowing effect is presented. Future lines of development will also be discussed.
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THPMR044	Short Term Dynamic Aperture with AC Dipoles	3496
	S. Mönig, J.M. Coello de Portugal, A. Langner, E.H. Maclean, T. Persson, R. Tomás CERN, Geneva, Switzerland
	The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. This paper will report the results of studies of the effect of the AC dipole on the dynamic aperture.
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THPMR048	Analysis of Nonlinear Effects for IDs at the SPS Storage Ring	3512
	S. Krainara, P. Klysubun, S. Kongtawong, T. Pulampong, P. Sudmuang, P. Sunwong SLRI, Nakhon Ratchasima, Thailand
	Funding: Synchrotron Light Research Institute (Public Organization) To generate intense and high energy synchrotron radiation at the Siam Photon Source (SPS) 1.2 GeV storage ring, two insertion devices (IDs), namely, a 2.2 T hybrid multipole wiggler (MPW) and a 6.5 T superconducting wavelength shifter (SWLS), have been installed and operated since 2013. The angular kicks due to the nonlinear effects generated by the IDs represented by kick maps were used in our analysis. The optics distortion was compared to the ones obtained from calculation using hard-edge model and measurement results. In order to investigate the effects of IDs on the beam dynamics, Frequency Map Analysis (FMA) was employed. The effects of the IDs and their compensation are presented herewith.
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THPMR049	Minimization of Nonlinear Effects of Insertion Devices at SPS Storage Ring	3515
	P. Sunwong, P. Klysubun, S. Kongtawong, S. Krainara, T. Pulampong, P. Sudmuang SLRI, Nakhon Ratchasima, Thailand T. Pulampong JAI, Oxford, United Kingdom
	Funding: Synchrotron Light Research Institute PO. Box 93 Nakhon Ratchasima 30000 Thailand Nonlinear effects of insertion devices were studied for the Siam Photon Source (SPS) storage ring. Despite the fact that shimming technique was used to minimize the nonlinear components of magnetic field integral arising from random errors, the nonlinear dynamics effects still remain. It was found that calculated dynamic field integrals are largest in the 2.2 T Hybrid Multipole Wiggler (MPW). Dynamics effects of insertion devices are attributed to the wiggling trajectory of electron in the region of magnetic field roll-off due to finite pole width. For better and more effective operation of the SPS storage ring, multipole components of the dynamic field integral in the MPW have to be further reduced.
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THPMR050	Studies to Install a Multipole Wiggler by Removing a Chromatic Sextupole in the Diamond Storage Ring	3518
	B. Singh, M. Apollonio, R. Bartolini, E. Koukovini-Platia, I.P.S. Martin, T. Pulampong, R.P. Walker DLS, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	Investigations are underway for the possible use of an achromat to install a short multipole wiggler by removing a chromatic sextupole in cell-11 of the storage ring. The effect on emittance and energy spread are found to be small, however the impact on lifetime and injection are very significant if the chromaticity is corrected normally (globally). The MOGA genetic algorithm is used to optimize the lifetime and injection efficiency in this case. We used local mirror chromatic sextupole and other chromatic sextupole family for chromaticity correction in which case the genetic algorithm found solution that restores lifetime and injection efficiency. In this paper the results of MOGA simulations using various schemes for chromaticity correction and test results in presently operational optics will be discussed.
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THPMR052	Compact, Microtron-Based Gamma Source	3522
	R.J. Abrams, M.A.C. Cummings, R.P. Johnson, S.A. Kahn, G.M. Kazakevich Muons, Inc, Illinois, USA
	Funding: This work was supported U.S. DOE SBIR Grant DE-SC0013795. The conceptual design of a prototype S-band pulsed, 9.5 MeV compact microtron with type-II injection is described. Estimates of parameters such as beam current and cathode lifetime, and comparisons with X-band and C-band parameters are presented. The electron beam can be extracted at various energies up to 9.5 MeV. Estimated yields of gammas produced at 6.5 MeV operation and estimated yields of gammas and neutrons produced at 9.5 MeV are presented.
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THPMR053	Influence of Magnet Multipole Field Components on Beam Dynamics in the JLEIC Ion Collider Ring	3525
	G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y. Nosochkov, M.-H. Wang SLAC, Menlo Park, California, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515. To get a luminosity level of a few 10³³ cm^-2ses⁻¹ at all design points of the Jefferson Lab Electron Ion Collider (JLEIC) project, small β* values in both horizontal and vertical planes are necessary at the Interaction Point (IP) in the ion collider ring. This also means large β in the final focus area, chromaticity correction sections, etc. which sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole field components of magnets are surveyed to find a possible compromise between the requirements and what can be realistically achieved by a magnet manufacturer. This paper describes that work. Moreover, non-linear field dedicated correctors are also studied to provide semi-local corrections of specific multipole field components.
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THPMR054	Error Correction for the JLEIC Ion Collider Ring	3528
	G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y. Nosochkov, M.-H. Wang SLAC, Menlo Park, California, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515. The sensitivity to misalignment, magnet strength error, and BPM noise is investigated in order to specify design tolerances for the ion collider ring of the Jefferson Lab Electron Ion Collider (JLEIC) project. Those errors, including horizontal, vertical, longitudinal displacement, roll error in transverse plane, strength error of main magnets (dipole, quadrupole, and sextupole), BPM noise, and strength jitter of correctors, cause closed orbit distortion, tune change, beta-beat, coupling, chromaticity problem, etc. These problems generally reduce the dynamic aperture at the Interaction Point (IP). According to real commissioning experiences in other machines, closed orbit correction, tune matching, beta-beat correction, decoupling, and chromaticity correction have been done in the study. Finally, we find that the dynamic aperture at the IP is restored. This paper describes that work.
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THPOR013	Magnet Error Effect on Dynamic Aperture in CEPC	3798
	S. Bai, J. Gao, Y. Wang, D.J. Xiao IHEP, Beijing, People's Republic of China
	With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 1034 cm^-2s⁻¹) is becoming more popular in the accelerator world. The CEPC project in China is one of them. The performance of the machine can be influenced by the existence of every kind of inaccuracies of the magnets, such as misalignment errors and field errors, multipole errors etc on. In this paper, we reported the errors that used in the CEPC beam dynamic study, and the influence on dynamic aperture of the CEPC main ring when introducing these kinds of errors.
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THPOR032	Effect and Optimisation of Non-Linear Chromatic Aberrations of the CLIC Drive Beam Recombination at CTF3	3852
	D. Gamba, R. Corsini, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland P. Burrows JAI, Oxford, United Kingdom P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	The CLIC design relies on the two-beam acceleration principle, i.e. the energy transfer from the so called drive beam to the main colliding beams. At the CLIC Test Facility (CTF3) at CERN the feasibility of this principle is being tested in terms of performance and achievable specifications. The high-current drive beam is generated by recombining its parts in a delay loop and a combiner ring. Preserving the drive beam emittance during the recombination process is crucial to ensure beam-current and power production stability. Present theoretical and experimental studies show that non-linear energy dependence of the transverse optics heavily spoils the quality of the recombined beam. Conventionally these effects are cured by means of non-linear corrections using sextupoles. In this work we propose a mitigation of these effects by optimising the linear lattice, leading to a more robust and easy to operate drive beam recombination complex. The latest results are presented.
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THPOR055	Characterisation of the SPS Slow-extraction Parameters	3918
	F.M. Velotti, W. Bartmann, T. Bohl, C. Bracco, K. Cornelis, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel CERN, Geneva, Switzerland
	The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain but its main users are the fixed-target experiments located in the North Area (NA). The beams, which are among the most intense circulating in the SPS, are extracted to the NA over several thousands of turns by exploiting a third-integer resonant extraction. The unavoidable losses intrinsic to such an extraction makes its optimisation one of the main priorities for operation, to reduce beam induced activation of the machine. The settings of the extraction systems, together with the tune sweep speed and the beam characteristics (momentum spread, emittance, etc.) are the parameters that can be controlled for spill and loss optimisation. In this paper, the contribution of these parameters to the slow-extraction spill quality are investigated through tracking simulations. The simulation model is compared with beam measurements and optimisations suggested.
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Paper

Title

Page

Design and Optimization Strategies of Nonlinear Dynamics in Diffraction-limited Synchrotron Light Sources

33

R. Bartolini
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

This talk introduces the most recent achievements in the control of nonlinear dynamics in electron synchrotron light sources, with special attention to diffraction limited storage rings. Guidelines for the design and optimization of the magnetic lattice are reviewed and discussed.

Slides MOZA02 [4.952 MB]

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THOBA01

RF Pinger Commissioning and Beam Dynamics Studies at NSLS-II

3161

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

Funding: DOE contract DE-SC0012704
NSLS II storage ring RF system has the digital ramp control function, enabling rapid change of the cavity phase and amplitude. This, together with largely overcoupled RF cavity and transmitter geometry, enables the possibility to "ping" the beam in longitudinal phase space. Similar to the pinger commonly used for transverse beam dynamic studies, the RF jump presents with a powerful tool for investigation of the machine longitudinal beam dynamics. During our beam studies, RF phase was jumped within a short interval of time (less than synchrotron period). Using turn-by-turn data from BPMs we measured the machine energy acceptance with and without damping wigglers. This paper presents the beam study results.

Slides THOBA01 [4.365 MB]

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THPMB019

Comparing the Performance of MOGA and MOPSO in Optimization of the HEPS Performance

3266

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

The High Energy Photon Source (HEPS), a kilometre- scale diffraction-limited storage ring light source, with a beam energy of 5 to 6 GeV and emittances of a few tens of pm.rad, is to be built in Beijing. A preliminary design with a hybrid 7BA lattice, an emittance of 60 pm.rad and a circumference of about 1.3 kilometers, has been made. Based on this design, we optimized the linear and nonlinear performance of the ring with the MOGA and MOPSO algorithms. From comparison of the performance of these two algorithms, it was found that MOPSO promises higher diversity than MOGA, while MOGA can reach better convergence than MOPSO. To reach a true Pareto front, a successive and iterative implementation of the PSO and MOGA, rather than using either of these two algorithms, is suggested.

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THPMR006

Muon Beam Tracking and Spin-Orbit Correlations for Precision g-2 Measurements

3397

D. Tarazona, M. Berz, R. Hipple, K. Makino, M.J. Syphers
MSU, East Lansing, Michigan, USA
M.J. Syphers
Fermilab, Batavia, Illinois, USA

The main goal of the Muon g-2 Experiment (g-2) at Fermilab is to measure the muon anomalous magnetic moment to unprecedented precision. This new measurement will allow to test the completeness of the Standard Model (SM) and to validate other theoretical models beyond the SM. The close interplay of the understanding of particle beam dynamics and the preparation of the beam properties with the experimental measurement is tantamount to the reduction of systematic errors in the determination of the muon anomalous magnetic moment. We describe progress in developing detailed calculations and modeling of the muon beam delivery system in order to obtain a better understanding of spin-orbit correlations, nonlinearities, and more realistic aspects that contribute to the systematic errors of the g-2 measurement. Our simulation is meant to provide statistical studies of error effects and quick analyses of running conditions for when g-2 is taking beam, among others. We are using COSY, a differential algebra solver developed at Michigan State University that will also serve as an alternative to compare results obtained by other simulation teams of the g-2 Collaboration.

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THPMR011

Injection Dynamics for Sirius Using a Nonlinear Kicker

3406

L. Liu, X.R. Resende, A.R.D. Rodrigues, F. H. de Sá
LNLS, Campinas, Brazil

The concept of injection using a single nonlinear kicker has been proposed and tested in several existing storage rings with reduction in the stored beam oscillations during the accumulation process. Despite the good results, this scheme has not yet been adopted for routine operation in these machines due to the reduced injection efficiency. The main cause for reduction in efficiency is precisely the nonlinearity of the kick at the injected beam position and the generally large injected beam size. In this paper we study the injection dynamics in the Sirius storage ring where beam accumulation is based only on the use of a nonlinear kicker. The whole injection system has been optimized from the start for high injection efficiency.

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THPMR012

Optimization of Nonlinear Dynamics for Sirius

3409

F. H. de Sá, L. Liu, X.R. Resende
LNLS, Campinas, Brazil

In this work we describe the optimization of the non-linear dynamics for the Sirius storage ring. The strong sextupoles of the lattice, necessary to correct the linear chromaticities, generate higher order terms in the tune-shifts with amplitude and energy, which may result in a large tune footprint for the machine. The configuration the sextupole families found that wraps this tune footprint and thus avoids dangerous resonances was achieved with minimization of Hamiltonian driving terms and tracking-based multi-objective algorithms include realistic values of misalignment and excitation errors of the magnets, orbit correction, insertion devices fields and real vacuum chamber apertures.

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THPMR014

Core-halo Limits and Beam Halo-formation Dynamic

3417

M. Valette, P.A.P. Nghiem
CEA/IRFU, Gif-sur-Yvette, France
N. Pichoff
CEA/DSM/IRFU, France

In high intensity linear accelerators, space charge related instabilities and effects are the cause of emittance increase and beam losses. The mechanism of halo formation due to a mismatched beam causing parametric resonances and energy transfer between phase-spaces is one of them. The previously defined one dimensional core-halo limit [1][2] was extended to two dimensional distributions [3][4]. This halo characterization method is applied to a classical case of transport for halo formation studies: the transport of a mismatched beam. Our method provides a core-halo limit that matches the expected halo formation mechanism with a very good precision.
* Appl. Phys. Lett. 104, 074109 (2014)
** Phys. Plasmas, 22, 083115, (2015)
*** IPAC (2015) MOPWA010
**** TBP

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THPMR015

RCDS Optimizations for the ESRF Storage Ring

3420

S.M. Liuzzo, N. Carmignani, L. Farvacque, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

The Robust Conjugate Direction Search (RCDS)* optimizer is applied for online optimizations of the ESRF accelerators. This paper presents the successful application of the algorithm in reducing vertical emittance, improving injection efficiency and increasing lifetime. A new set of sextupole settings to increase chromaticity has been obtained with lifetimes comparable to the existing one. This allows to run with double current in a single bunch, and unifies the optics for few bunch (except 4x10 bunches) and multi-bunch modes.
* X. Huang, J. Corbett, J. Safranek, J. Wu, "An algorithm for online optimization of accelerators", Nucl. Instr. Methods, A 726 (2013) 77-83.

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THPMR017

Resonance Island Experiments at BESSY II for User Applications

3427

P. Goslawski, J. Feikes, K. Holldack, A. Jankowiak, M. Ries, M. Ruprecht, A. Schälicke, G. Wüstefeld
HZB, Berlin, Germany
R. Ovsyannikov
BESSY GmbH, Berlin, Germany

Beam storage close to a tune resonance (Qx = 1/3, 1/4) can generate resonance island buckets in the x,x' phase space providing a second stable island orbit winding around the standard orbit. Experiments with such an operation mode have been conducted at BESSY II and the Metrology Light Source (MLS)*,**. The two orbits are well separated, with good life time and stability. Such operation mode will offer additional operation flexibility and allows users to choose their radiation source point from one or the other orbit. It has the potential to fulfill simultaneously conflicting user demands, e.g., high vs. low beam current and single or few bunch filling vs. multibunch filling. We discuss the required beam optics setup and present successful measurements taken at photon beamlines at BESSY II.
* P. Goslawski et al., "Bunch Separation by Transverse Resonance Island Buckets", ESLS XXIII Workshop, 2015, Villigen, Switzerland.
** M. Ries et al., Proc. IPAC 2015, Richmond, USA, MOPWA021.

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THPMR018

Ion-Optics of Antiproton Separator at FAIR

3431

S.A. Litvinov, A. Dolinskyy, K. Knie
GSI, Darmstadt, Germany
I. Koop, P.Yu. Shatunov, I.M. Zemlyansky
BINP SB RAS, Novosibirsk, Russia

In the framework of antiproton program at FAIR project, the large acceptance antiproton separator is dedicated for the effective separation of the secondary antiprotons from the primary protons and the secondary beams of other particle species and subsequent transportation to the Collector Ring (CR). Here we present the latest ion-optical layout of the antiproton separator and possible second-order correction scheme as well.

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THPMR020

Bunch Purity Measurements at PETRA III

3434

J. Keil, H. Ehrlichmann
DESY, Hamburg, Germany

Since 2010 the 6 GeV synchrotron light source PETRA III is in operation. With a horizontal emittance of 1.2 nm*rad, a coupling of typically 1% and a total beam current of 100 mA the machine provides extremely brilliant synchrotron radiation for the users. For time-resolved measurements a filling pattern with 40 equidistant bunches with equal charge is used. To measure parasitic bunches between the main bunches two beamlines are equipped with avalanche photodiodes (APD) and time to digital converters (TDC) electronics. Besides parasitic bunches originating from the pre-accelerators of PETRA III it has been observed that initially empty buckets following the main bunch are populated. Measurements of the effect will be discussed and compared with simulations.

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THPMR021

Bmad Model of COSY, Status and Progress

3437

Y. Dutheil
FZJ, Jülich, Germany

Abstract The COSY in Jülich is a versatile machine with a long history of polarized proton acceleration. A new model of COSY based on the Bmad library was developed to simulate beam and spin dynamics. Original methods of lattice design, notably multi-objective lattice optimization, were explored. This contribution presents the status and development steps of the Bmad model of COSY. Some of the latest simulations will also be discussed.

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THPMR022

Non-linear Optimization of Storage Ring Lattice for the SPring-8 Upgrade

3440

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

A project of upgrading the SPring-8 facility is ongoing to convert the present storage ring to a high-coherence hard X-ray source (SPring-8-II). To achieve the emittance value of less than 0.2 nmrad at 6 GeV, we adopted a 5-bend achromat lattice with dipoles having longitudinal field gradient. In this lattice the betatron phase between the two dispersion arcs was set to (2n+1)PI to suppress dominant harmful effects of chromaticity-correcting sextupoles. By detuning this phase, optimizing sextupole strengths in a cell and introducing octupoles, we obtained a sufficient dynamic aperture (DA) for beam injection even for the symmetry-broken ring having four long straight sections and a high-beta injection section. However, the off-momentum behavior such as the non-linear chromaticity still needs to be optimized to achieve the momentum acceptance (MA) of 3% or larger. We have thus been investigating the possibility to increase both the DA and MA by introducing several phase-matched sextupole pairs. The presentation will report the obtained results by this approach.

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THPMR025

Simulation of Beam Behavior Caused by Odd Harmonics of Beam Loading in J-PARC RCS

3443

M. Yamamoto, M. Nomura, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Hara, K. Hasegawa, C. Ohmori, M. Toda, M. Yoshii
KEK, Tokai, Ibaraki, Japan

The J-PARC RCS accelerates 2 bunches at the harmonic number 2. The major Fourier component of the beam current is even harmonics. However, the odd harmonics grow under some conditions even though they are very small amplitude at the beginning. We describe the the particle tracking simulation results for the odd harmonic beam loading effect in the RCS.

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THPMR026

SESAME Storage Ring Beam Dynamics in View of the Results of its Magnet Measurements

3446

M. Attal, E. Huttel
SESAME, Allan, Jordan

SESAME storage ring magnets have been recently constructed and measured. The storage ring beam dynamics is reviewed in this article in view of these results. Moreover it is shown how the optical impact of dipoles main field errors is more mitigated by sorting dipoles in the storage ring in addition to the alignment optimization method suggested by magnetic measurement outcome.

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THPMR030

Results of the Use of Axisymmetric RF Focusing in Proton Linacs at Energies up to 7 MeV

3449

V.S. Dyubkov, Ya.V. Shashkov
MEPhI, Moscow, Russia

During a few decades axisymmetric RF structures with a focusing by means of nonsynchronous spatial harmonics of electromagnetic field are offered instead of proven RFQ. An effectiveness of these structures in the energy range up to 2 MeV was shown in a number of papers. An effectiveness of these structures in the energy range up to 7 MeV is considered in this paper. Results of an analytical investigation and a numerical simulation of self-consistent proton dynamics are presented and discussed.

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THPMR031

Turn-by-Turn Measurements for Beam Dynamics at Vepp-5 Damping Ring

3452

M.F. Blinov, K.V. Astrelina, V.V. Balakin, O.I. Meshkov, A.A. Starostenko
BINP SB RAS, Novosibirsk, Russia
V.L. Dorokhov
BINP, Novosibirsk, Russia

Preinjector complex VEPP-5 is being constructed for high rate production and acceleration of electrons and positrons beams up to energy 510 MeV. Both kinds of particles accumulated in the damping ring and after achieving of needed intensity the beams would be transported alternatively to VEPP-3/VEPP-4M or to BEP/VEPP-2000 colliders. At this paper basic parameters of damping ring presented. All measurements were carried out for electron beam with energy 385 MeV. For turn-by-turn measurements 12 beam position monitors were used. In order to improve precision of measured value NAFF algorithm was applied. For measurements of longitudinal beam profile optical phi-dissector was used.

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THPMR032

Dynamical Aperture Control in Accelerator Lattices With Multipole Potentials

3455

I.A. Morozov, E.B. Levichev
BINP SB RAS, Novosibirsk, Russia

We apply two analytical methods to control accelerator dynamic aperture (DA) with multipole potentials. Both methods assume that accelerator model can be represented as a product of unperturbed and perturbed exponential operators with exponent of perturbed operator given as formal power series in perturbation parameter and known dependence of series coefficients on lattice parameters such as multipole strength distribution. Normal form method can be applied to the above representation and then lattice parameters are used to control normal form Hamiltonian coefficients. Hamiltonian control can be used to compute control term and lattice parameters are then fitted to approximate corresponding controlled operator. Theoretical results as well as model examples are presented.

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THPMR034

Simulation of Single Particle Dynamics in a Compact Planar Wiggler

3458

D.A. Shkitov, A.E. Harisova, Y.N. Sutygina
TPU, Tomsk, Russia

In this report a description of a simple approach how to simulate a single particle track in a 3D magnetic field using Radia code is presented. Such a simulation maybe useful in order to briefly estimate in a short time the beam dynamics in the magnetic field produced by means of different types of the magnet devices. As an example, a low energy relativistic electron tracking* is performed in a compact 30 cm planar wiggler which produced ~0.4 T magnetic field. The changes of the electron entrance point and motion direction are also available. This simulation is carried out using three-dimensional magnetostatic code - Radia**, where the 4th order Runge-Kutta method was implemented for the trajectory calculations. Since Radia is the Mathematica add-on then a small Wolfram Language code is developed to create the wiggler model, to calculate the electron trajectory and to illustrate the simulation results.
* Knyazik A. et al. Status of UCLA helical permanent-magnet undulator // Proc. of PAC, Canada, WE5RFP076 (2009) 2441
** http://www.esrf.eu/Accelerators/Groups/InsertionDevices/Software/Radia

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THPMR035

Low Horizontal Beta Optics for ALBA

3461

G. Benedetti, J. Campmany, Z. Martí
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The ALBA insertion device beamlines have a horizontal and vertical rms source size of 130 and 5.5 microns. Protein crystallography beamlines (Xaloc) would benefit from a reduction of the horizontal and increase of the vertical beam size, to gain spatial resolution and avoid anisotropy effects. A modified lattice with horizontal and vertical beam size of 74 and 9 microns has been setup and tested, breaking the ring symmetry, with different setting of the six neightbouring quadrupoles at each side of the Xaloc insertion device. Such configuration keeps the nominal emittance almost unvaried and the working point is recovered by small changes in the quadrupole strengths of the four symmetric matching sections. A dedicated setting of the nine available sextupole families has been obtained by numerical optimization of the dynamical apertures and tune shifts. The lattice settings have been satisfactorily tested. The measured lifetime is reduced a factor two and the injection efficiency decreases to 60%. Finally, the option of increasing the number of sextupole families, to recover the dynamic aperture and guarantee the injection efficiency, has been studied.

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THPMR036

Improved Methods for the Measurement and Simulation of the CERN SPS Non-linear Optics

3464

H. Bartosik, A. Oeftiger, M. Schenk, F. Schmidt, M. Titze
CERN, Geneva, Switzerland

Good knowledge of the non-linear properties of the SPS lattice is crucial for modelling and optimising the machine performance in the presence of collective effects leading to incoherent tune spreads such as space charge, e-cloud and beam coupling impedance. In view of the LHC injectors upgrade (LIU) project and the future SPS operation in a regime dominated by such collective effects, detailed measurements of the SPS non-linear chromaticity and detuning with amplitude have been performed for the two optics configurations presently available for LHC type beams. The measurement results are used to fit systematic multipole components to the main magnets of the SPS MADX model as a basis for the non-linear machine model that can be used for beam dynamics simulations. The implications for the operation of the SPS with the LIU beam parameters are discussed.

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THPMR037

Observations of Resonance Driving Terms in the LHC during Runs I and II

3468

F.S. Carlier, J.M. Coello de Portugal, E.H. Maclean, T. Persson, R. Tomás
CERN, Geneva, Switzerland

Future operations of the LHC will require a good understanding of the nonlinear beam dynamics. In 2012, turn-by-turn measurements of large diagonal betatron excitations in LHC Beam 2 were taken at injection energy. Spectral analysis of these measurements shows an anomalous octupolar spectral line at frequency -Qx-2Qy in the horizontal motion. The presence of this spectral line, as well as other lines, was confirmed by measurements taken for LHC Beam 1 and Beam 2 during the commissioning in 2015. We take a close look at the various spectral lines appearing in the LHC transverse motion in order to improve the LHC nonlinear model.

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THPMR038

Non-Linear Errors in the Experimental Insertions of the LHC

3472

E.H. Maclean, F.S. Carlier, M. Giovannozzi, A. Langner, S. Mönig, T. Persson, P.K. Skowroński, R. Tomás
CERN, Geneva, Switzerland

Correction of nonlinear magnetic errors in low-β insertions can be of critical significance for the operation of a collider. This is expected to be of particular relevance to LHC Run II and the HL-LHC upgrade, as well as to future colliders such as the FCC. Current correction strategies for these accelerators have assumed it will be possible to calculate optimized local corrections through the insertions using a magnetic model of the errors. To test this assumption the nonlinear errors in the LHC experimental insertions have been examined via feed-down and amplitude detuning. It will be shown that while in some cases the magnetic measurements provide a sufficient description of the errors, in others large discrepancies exist which will require beam-based correction techniques.

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THPMR039

Commissioning of Non-linear Optics in the LHC at Injection Energy

3476

E.H. Maclean, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, A. Langner, L. Malina, T. Persson, P.K. Skowroński, R. Tomás
CERN, Geneva, Switzerland

Commissioning of the nonlinear optics at injection in the LHC was carried out for the first time in 2015 via beam-based methods. Building upon studies performed during Run I, corrections to the nonlinear chromaticity and detuning with amplitude were obtained. These corrections were observed to reduce beam-loss during measurement of linear optics.

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THPMR041

Implementation of High Order Symplectic Integrators with Positive Steps in Tracking Programs

3484

K. Skoufaris, Y. Papaphilippou
CERN, Geneva, Switzerland
J. Laskar
IMCCE, Paris, France
Ch. Skokos
University of Cape Town, Cape Town, South Africa

The symplectic integrators CSABAν & CSBABν are used in order to calculate single particles dynamics in accelerators and storage rings. These integrators present only positive steps and can be accurate up to the high order. They are compared with already existing splitting methods of MAD-X with respect to their impact on various beam dynamics quantities, for different beam elements.

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THPMR043

Performance of Transverse Beam Splitting and Extraction at the CERN Proton Synchrotron in the Framework of Multi-turn Extraction

3492

G. Sterbini, J.C.C.M. Borburgh, S. Damjanovic, S.S. Gilardoni, M. Giovannozzi, C. Hernalsteens, M. Hourican, A. Huschauer, K. Kahle, G. Le Godec, O. Michels
CERN, Geneva, Switzerland
C. Hernalsteens
EPFL, Lausanne, Switzerland

Considerable progress has been made in 2015 in the setting up of the multi-turn extraction (MTE) in the CERN Proton Synchrotron (PS). A key ingredient in this novel extraction technique is the beam splitting in transverse phase space. This manipulation is based on adiabatic trapping in stable islands of transverse phase space and requires mastering a number of devices in the PS ring. In addition, an in-depth review of all fast extractions schemes in the PS had been required due to the development and installation of a dummy septum to shield the actual magnetic septum. In this paper, the current performance of the beam splitting and of the extraction including the shadowing effect is presented. Future lines of development will also be discussed.

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THPMR044

Short Term Dynamic Aperture with AC Dipoles

3496

S. Mönig, J.M. Coello de Portugal, A. Langner, E.H. Maclean, T. Persson, R. Tomás
CERN, Geneva, Switzerland

The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. This paper will report the results of studies of the effect of the AC dipole on the dynamic aperture.

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THPMR048

Analysis of Nonlinear Effects for IDs at the SPS Storage Ring

3512

S. Krainara, P. Klysubun, S. Kongtawong, T. Pulampong, P. Sudmuang, P. Sunwong
SLRI, Nakhon Ratchasima, Thailand

Funding: Synchrotron Light Research Institute (Public Organization)
To generate intense and high energy synchrotron radiation at the Siam Photon Source (SPS) 1.2 GeV storage ring, two insertion devices (IDs), namely, a 2.2 T hybrid multipole wiggler (MPW) and a 6.5 T superconducting wavelength shifter (SWLS), have been installed and operated since 2013. The angular kicks due to the nonlinear effects generated by the IDs represented by kick maps were used in our analysis. The optics distortion was compared to the ones obtained from calculation using hard-edge model and measurement results. In order to investigate the effects of IDs on the beam dynamics, Frequency Map Analysis (FMA) was employed. The effects of the IDs and their compensation are presented herewith.

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THPMR049

Minimization of Nonlinear Effects of Insertion Devices at SPS Storage Ring

3515

P. Sunwong, P. Klysubun, S. Kongtawong, S. Krainara, T. Pulampong, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand
T. Pulampong
JAI, Oxford, United Kingdom

Funding: Synchrotron Light Research Institute PO. Box 93 Nakhon Ratchasima 30000 Thailand
Nonlinear effects of insertion devices were studied for the Siam Photon Source (SPS) storage ring. Despite the fact that shimming technique was used to minimize the nonlinear components of magnetic field integral arising from random errors, the nonlinear dynamics effects still remain. It was found that calculated dynamic field integrals are largest in the 2.2 T Hybrid Multipole Wiggler (MPW). Dynamics effects of insertion devices are attributed to the wiggling trajectory of electron in the region of magnetic field roll-off due to finite pole width. For better and more effective operation of the SPS storage ring, multipole components of the dynamic field integral in the MPW have to be further reduced.

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THPMR050

Studies to Install a Multipole Wiggler by Removing a Chromatic Sextupole in the Diamond Storage Ring

3518

B. Singh, M. Apollonio, R. Bartolini, E. Koukovini-Platia, I.P.S. Martin, T. Pulampong, R.P. Walker
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

Investigations are underway for the possible use of an achromat to install a short multipole wiggler by removing a chromatic sextupole in cell-11 of the storage ring. The effect on emittance and energy spread are found to be small, however the impact on lifetime and injection are very significant if the chromaticity is corrected normally (globally). The MOGA genetic algorithm is used to optimize the lifetime and injection efficiency in this case. We used local mirror chromatic sextupole and other chromatic sextupole family for chromaticity correction in which case the genetic algorithm found solution that restores lifetime and injection efficiency. In this paper the results of MOGA simulations using various schemes for chromaticity correction and test results in presently operational optics will be discussed.

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THPMR052

Compact, Microtron-Based Gamma Source

3522

R.J. Abrams, M.A.C. Cummings, R.P. Johnson, S.A. Kahn, G.M. Kazakevich
Muons, Inc, Illinois, USA

Funding: This work was supported U.S. DOE SBIR Grant DE-SC0013795.
The conceptual design of a prototype S-band pulsed, 9.5 MeV compact microtron with type-II injection is described. Estimates of parameters such as beam current and cathode lifetime, and comparisons with X-band and C-band parameters are presented. The electron beam can be extracted at various energies up to 9.5 MeV. Estimated yields of gammas produced at 6.5 MeV operation and estimated yields of gammas and neutrons produced at 9.5 MeV are presented.

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THPMR053

Influence of Magnet Multipole Field Components on Beam Dynamics in the JLEIC Ion Collider Ring

3525

G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Nosochkov, M.-H. Wang
SLAC, Menlo Park, California, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515.
To get a luminosity level of a few 10³³ cm^-2ses⁻¹ at all design points of the Jefferson Lab Electron Ion Collider (JLEIC) project, small β* values in both horizontal and vertical planes are necessary at the Interaction Point (IP) in the ion collider ring. This also means large β in the final focus area, chromaticity correction sections, etc. which sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole field components of magnets are surveyed to find a possible compromise between the requirements and what can be realistically achieved by a magnet manufacturer. This paper describes that work. Moreover, non-linear field dedicated correctors are also studied to provide semi-local corrections of specific multipole field components.

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THPMR054

Error Correction for the JLEIC Ion Collider Ring

3528

G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Nosochkov, M.-H. Wang
SLAC, Menlo Park, California, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515.
The sensitivity to misalignment, magnet strength error, and BPM noise is investigated in order to specify design tolerances for the ion collider ring of the Jefferson Lab Electron Ion Collider (JLEIC) project. Those errors, including horizontal, vertical, longitudinal displacement, roll error in transverse plane, strength error of main magnets (dipole, quadrupole, and sextupole), BPM noise, and strength jitter of correctors, cause closed orbit distortion, tune change, beta-beat, coupling, chromaticity problem, etc. These problems generally reduce the dynamic aperture at the Interaction Point (IP). According to real commissioning experiences in other machines, closed orbit correction, tune matching, beta-beat correction, decoupling, and chromaticity correction have been done in the study. Finally, we find that the dynamic aperture at the IP is restored. This paper describes that work.

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THPOR013

Magnet Error Effect on Dynamic Aperture in CEPC

3798

S. Bai, J. Gao, Y. Wang, D.J. Xiao
IHEP, Beijing, People's Republic of China

With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 1034 cm^-2s⁻¹) is becoming more popular in the accelerator world. The CEPC project in China is one of them. The performance of the machine can be influenced by the existence of every kind of inaccuracies of the magnets, such as misalignment errors and field errors, multipole errors etc on. In this paper, we reported the errors that used in the CEPC beam dynamic study, and the influence on dynamic aperture of the CEPC main ring when introducing these kinds of errors.

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THPOR032

Effect and Optimisation of Non-Linear Chromatic Aberrations of the CLIC Drive Beam Recombination at CTF3

3852

D. Gamba, R. Corsini, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The CLIC design relies on the two-beam acceleration principle, i.e. the energy transfer from the so called drive beam to the main colliding beams. At the CLIC Test Facility (CTF3) at CERN the feasibility of this principle is being tested in terms of performance and achievable specifications. The high-current drive beam is generated by recombining its parts in a delay loop and a combiner ring. Preserving the drive beam emittance during the recombination process is crucial to ensure beam-current and power production stability. Present theoretical and experimental studies show that non-linear energy dependence of the transverse optics heavily spoils the quality of the recombined beam. Conventionally these effects are cured by means of non-linear corrections using sextupoles. In this work we propose a mitigation of these effects by optimising the linear lattice, leading to a more robust and easy to operate drive beam recombination complex. The latest results are presented.

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THPOR055

Characterisation of the SPS Slow-extraction Parameters

3918

F.M. Velotti, W. Bartmann, T. Bohl, C. Bracco, K. Cornelis, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel
CERN, Geneva, Switzerland

The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain but its main users are the fixed-target experiments located in the North Area (NA). The beams, which are among the most intense circulating in the SPS, are extracted to the NA over several thousands of turns by exploiting a third-integer resonant extraction. The unavoidable losses intrinsic to such an extraction makes its optimisation one of the main priorities for operation, to reduce beam induced activation of the machine. The settings of the extraction systems, together with the tune sweep speed and the beam characteristics (momentum spread, emittance, etc.) are the parameters that can be controlled for spill and loss optimisation. In this paper, the contribution of these parameters to the slow-extraction spill quality are investigated through tracking simulations. The simulation model is compared with beam measurements and optimisations suggested.

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