IPAC2015 - List of Keywords (multipole)

Paper	Title	Other Keywords	Page
MOBC1	Towards Ultra-Low β^* in ATF2	optics, octupole, collider, linear-collider	38
	M. Patecki, A.V. Aloev, D.R. Bett, M. Modena, R. Tomás CERN, Geneva, Switzerland K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan E. Marín, G.R. White SLAC, Menlo Park, California, USA
	The Accelerator Test Facility 2 (ATF2) has already demonstrated the feasibility of Final Focus Systems based on the local chromaticity correction scheme and its focusing capabilities by reaching a vertical beam size at the virtual Interaction Point (IP) of less than 50 nm. The value of the chromaticity in ATF2 is comparable with the expected chromaticity in ILC, but 4 times lower than in a design of CLIC. ATF2 gives the unique possibility to test operation at CLIC chromaticity values by reducing the vertical beta function at the IP by a factor of 4 (the inverse proportionality of chromaticity with beta function value at IP is assumed). The experience collected in this way would be beneficial for both ILC and CLIC projects. Simulations show that the multipolar errors and Final Doublet fringe fields spoil the IP beam sizes at ATF2. Either increasing a value of the horizontal beta function or installing a pair of octupole magnets mitigate the impact of these aberrations. This paper summarizes the studies towards the realization of the ultra-low β^* optics in ATF2 and reports on the progress of the construction of the octupoles.
	Slides MOBC1 [1.566 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOBC1
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MOPWA016	Increasing the Dynamic and Momentum Apertures of the ThomX Ring by Means of Octupole Correctors	sextupole, octupole, resonance, dipole	121
	J.F. Zhang, P. Bambade, A. Faus-Golfe, H. Monard LAL, Orsay, France A. Faus-Golfe IFIC, Valencia, Spain A. Loulergue SOLEIL, Gif-sur-Yvette, France
	Funding: Work is supported by ANR-10- EQPX-51 and ANR-11-IDEX-0003-02, and also by grants from Region Ile-de-France. The electron ring of the compact Compton-backscattering X-ray source ThomX which is being built at LAL featured with a small circumference of 18 meters and a low beam energy 50-70 MeV, and its long term single particle dynamics is dominated by the non linear effects in the transverse and longitudinal planes. In this paper, we study the feasibilities to reduce the sextupole resonances and then increase the dynamic aperture and momentum aperture of the ThomX ring, using octupoles correctors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA016
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MOPWA033	Yacs - A New 2.5D FEM Eigenmode Solver for Axisymmetric RF-Structures	cavity, dipole, quadrupole, software	175
	B.D. Isbarn, B. Riemann, M. Sommer, T. Weis DELTA, Dortmund, Germany
	Funding: Work supported by the BMBF under contract no. 05K13PEB Most feasibility studies for modern accelerator concepts, including superconducting multicell RF-cavity-resonators in circular accelerators, depend on computing a large number of eigenmode frequencies and field patterns to obtain typical figures of merit. This task includes computational intensive numerical studies. To obtain the full eigenfrequency spectra most of these studies are performed in 3D, require a great amount of computation resources and thus are limited to a few hundred or thousand eigenmodes. To overcome this issue, some codes make use of the axisymmetric geometry of most of the RF-cavity-resonator structures and solve the problem in 2D. Solving in 2D however reduces the eigenmode spectra to eigenmodes with no azimuthal dependencies (so called monopole-modes). Due to the lack of freely available and easy to use 2.5D eigenmode solvers which are able to solve for the full 3D field in a reduced 2.5 dimensional problem, we developed yet another cavity solver (Yacs), a simple FEM based solver capable of solving for the full 3D eigenmodes of axisymmetric problems while only requiring a fraction of the computation resources required by most modern 3D codes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA033
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MOPWA065	Uniformization of the Transverse Beam Profile by a New Type Nonlinear Magnet	octupole, target, dipole, simulation	272
	G. Gu, W.B. Liu IHEP, Beijing, People's Republic of China
	The uniform particle beam is desirable in many beam applications. One method to get this type of beam distribution is using octupoles, but loss of particles in the halo will be produced by this method. To reduce the beam loss, a new type of magnet is proposed in this paper. The field in the middle region of the new type magnet is similar to the octupole magnet field, but the rate of rise decline quickly in the edge. So that the particle in the edge experience a lower magnet field, and this would result in less particle loss. We also add a mechanical structure on the new type magnet to make it possible to adjust the size of middle region. So that the magnet can adapt to different transverse dimensions of the beam, and this would further reduce particle loss. Some numerical simulations have been done respectively with octuples and the new type of magnet. The simulation results show that the new type of magnet could get the uniform distribution of particle beam with less particle loss. We are processing a magnet now, and an experiment to test the magnet will be arranged on CPHS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA065
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MOPJE075	Tracking Through Analytic Quadrupole Fringe Fields With GPT	quadrupole, simulation, space-charge, interface	489
	S.B. van der Geer, M.J. de Loos Pulsar Physics, Eindhoven, The Netherlands B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	In the early design stages it is customary to work with a highly simplified analytic model to describe the beam line. Dipoles and quadrupoles are often based on hard-edged approximations. This is not only unrealistic, it also significantly slows down time-domain spacecharge tracking codes such as the General Particle Tracer (GPT) code. The underlying reason for the poor performance is that despite the fact that the simple hard-edged field equations are fast to evaluate, they force the integration process to use excessively small step sizes near the fields discontinuities in order to achieve the desired accuracy. In other worlds, the apparently simple equations turn out to be the most difficult ones to evaluate numerically. An obvious solution is to switch to field-maps, but this is not practical in the early design stages. In this contribution we show a new solution implemented in the GPT code based on analytical expressions for the fringes where the transverse size of the magnet is properly taken into account. In addition to producing more realistic results, the smooth fields increase tracking speed by over an order of magnitude for typical test cases.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE075
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MOPMA050	Smooth Fast Multipole Method for Space Charge Tracking: An Alternate to Particle-In-Cell	space-charge, simulation, framework, emittance	663
	A.J. Gee, B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA B. Erdelyi ANL, Argonne, USA
	The fast multipole method (FMM) algorithm was developed by Greengard and Rokhlin in 1987 . As one of the top ten algorithms of the 20th century, it has been applied in a wide range of fields. The FMM complexity is O(N), where N is the number of articles, allowing for large-scale simulations. However, it includes all the two-body collisional forces, in contrast to other methods such as the popular particle in-cell (PIC) methods. While collisionality can be very important, many applications require only the mean field effects. PIC is frequently used in this regime. Due to recent concerns of unphysical effects of grids, interpolation and other approximations in PIC codes, an alternative based on different underlying assumptions would prove enlightening. For these cases, a smoothed or softened FMM using a Plummer-like smoothing parameter holds much promise. Unfortunately, the original FMM based on analytic expansions of the 1/r-like potentials does not allow for Plummer softening. We present our new soft-FMM employing differential algebras (DA) to obtain the modified expansions. We also compare the performance of the smoothed DA-FMM with examples from PIC simulations. L. Greengard and V. Rokhlin. “A fast algorithm for particle simulations".
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MOPMN021	NSLS-II Storage Ring BPM Button Development	vacuum, impedance, simulation, storage-ring	748
	A. Blednykh, B. Bacha, G. Bassi, W.X. Cheng, C. Hetzel, B.N. Kosciuk, D. Padrazo, O. Singh BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract DE-AC02-98CH10886 The NSLS-II BPM Button design and its development process have been described. Subjects discussed include BPM Button impedance optimization, design and construction, production, BPM Button selection and a first temperature measurements at 200mA average current within 1200 bunches.
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TUAD1	Magnet Design and Control of Field Quality for TPS Booster and Storage Rings	quadrupole, dipole, sextupole, vacuum	1370
	J.C. Jan, C.H. Chang, C.-T. Chen, H.H. Chen, Y.L. Chu, M.-H. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, G.-H. Luo, I.C. Sheng, C.S. Yang, Y.T. Yu NSRRC, Hsinchu, Taiwan
	High-quality and very demanding magnets were designed, fabricated, field quality controlled and installed in the Taiwan Photon Source (TPS). The Storage Ring (SR) lattice is based on double-bend achromat structure with 1.6 nm-rad emittance and slight dispersion in straight sections. The fabrication and field measurement of these magnets were completed in Oct. 2013. The first synchrotron light from TPS storage ring, without applying any corrector at 3 GeV, was observed on Dec. 31, 2014. It indicates that the profile precision and field quality of magnets, and girders alignment reach world class standard. The integral multipoles components of the 240 SR quadrupole and 168 SR sextupole magnets conform to strict specifications. The maximum offset of measured mechanical center in magnets is better than 0.01 mm after feet shimming. The magnetic center offset of the magnets is within 0.02 mm inspected by rotating-coil method. The magnets’ field quality of booster’s pure quadrupole and combined-function quadrupole were accepted according to the errors specifications from beam dynamics and also in the beam commissioning. A permeability study of vacuum chamber was implemented during the booster ring hardware testing. The magnetic field of magnets is distorted by the permeability of vacuum chamber. Study of multipole errors due to magnetized vacuum chamber inside the magnet will be discussed.
	Slides TUAD1 [2.698 MB]
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TUPWA014	Influence of errors on the ESRF Upgrade Lattice	survey, lattice, dynamic-aperture, alignment	1426
	S.M. Liuzzo, J.C. Biasci, N. Carmignani, L. Farvacque, G. Gatta, G. Le Bec, D. Martin, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	To determine the tolerable alignment and magnetic errors for the ESRF upgrade, we study their influence on Touschek lifetime and dynamic aperture. The correction of each set of errors studied is performed with a commissioning-like procedure, from the search for a closed orbit to the correction of resonance driving terms. Each kind of error is studied independently for each relevant family of magnets. The tolerable values deduced from the analysis are within the practical limits. The impact of the measured and simulated survey errors is also considered, defining the position of the currently installed lattice as the one of least impact for the realignment of X-ray beamlines.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA014
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TUPJE005	Development of Pulsed Multipole Magnet for Aichi SR Storage Ring	storage-ring, electron, injection, synchrotron	1616
	K. Ito, M. Hosaka, A. Mano, T. Takano, Y. Takashima Nagoya University, Nagoya, Japan K. Hayashi, M. Katoh UVSOR, Okazaki, Japan N. Yamamoto KEK, Ibaraki, Japan
	The Aichi synchrotron radiation (Aichi SR) center is an industrial oriented synchrotron light source facility. The electron energy and circumference of the storage ring are 1.2 GeV and 72 m. The natural emittance is 53 nm-rad. Since the pulsed multipole injection scheme provides great advantages for relatively smaller SR rings, we are developing a pulsed multipole injection system for Aichi SR storage ring. In this system, it is essential to minimize the perturbation to the stored beam. To realize the required performances, we have to minimize the residual field at stored beam position, taken into account the field generated by the copper current lead of the input terminal. In addition, we carried out the analytical calculation to estimate the magnet field due to the current lead and optimized the geometrical structure of them. Construction of the multipole magnet will be completed in March 2015 and the field measurement will be carried out in April. In this presentation, we report the detail of the magnet design and the measurement results of pulsed magnetic field for the manufactured magnet. N. Yamamoto, et. al., NIM A 767, 26-33 (2014)
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TUPJE046	Investigation of the Injection Scheme for SLS 2.0	injection, kicker, lattice, booster	1720
	Á. Saá Hernández, M. Aiba PSI, Villigen PSI, Switzerland
	SLS2, an upgrade of the Swiss Light Source (SLS), aiming at a natural horizontal emittance in the range of 100 pm is planned and under study. This will be achieved by replacing the current magnet lattice of the electron storage ring by a new multibend achromat magnet lattice, while reusing the injector chain and most of the existing infrastructures. The new low emittance ring will impose more restrictive constraints on injection due to a smaller machine aperture and a very compact lattice, dominated by non-linearities. We performed a study to find the optimum injection scheme for SLS2 among the conventional and more advanced schemes; namely multipole kicker injection (off-axis and also on-axis matched to the off-momentum closed orbit) and longitudinal injection.
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TUPJE063	Hybrid Seven-Bend-Achromat Lattice for the Advanced Photon Source Upgrade	lattice, emittance, injection, sextupole	1776
	M. Borland, V. Sajaev, Y. Sun ANL, Argonne, Ilinois, 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. A hybrid seven-bend-achromat lattice has been designed for the APS upgrade. We describe the design goals, constraints, and methodology, including the choice of beam energy. Magnet strength and spacing is compatible with engineering designs for the magnets, diagnostics, and vacuum system. Dynamic acceptance and local momentum acceptance were simulated using realistic errors, then used to assess workable injection methods and predict beam lifetime. Predicted brightness is two to three orders of magnitude higher than the existing APS storage ring. Pointers are provided to other papers in this conference that cover subjects in more detail.
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TUPTY054	RF Design of the CLIC Structure Prototype Optimized for Manufacturing from Two Halves	linac, wakefield, simulation, collider	2147
	H. Zha, A. Grudiev CERN, Geneva, Switzerland V.A. Dolgashev SLAC, Menlo Park, California, USA
	We present the RF design of a 12GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype. The structure is made from two longitudinally symmetric halves. The main manufacturing process of each half is precision milling. The structure uses the same iris dimensions as the CLIC-G structure but the cell shape is optimized for milling. The geometry is optimized to reduce the surface electric and magnetic fields and the modified Poynting vector. This design can potentially reduce fabrication cost.
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WEPWA041	Plans for a Linear Paul Trap at Rutherford Appleton Laboratory	quadrupole, plasma, ion, resonance	2590
	D.J. Kelliher, S. Machida, D.C. Plostinar, C.R. Prior, S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	For over a decade, Linear Paul Traps (LPT) have been used in the study of accelerator beam dynamics. LPT studies exploit the similarity of the Hamiltonian with that of a beam in a quadrupole channel while having advantages in the flexibility of parameter choice, compactness and low cost. In collaboration with Hiroshima University, LPT research planned at STFC Rutherford Appleton Laboratory in the UK aims to investigate a range of topics including resonance crossing, halo formation, long-term stability studies and space-charge effects. Initially, a conventional quadrupole-based LPT will be built at RAL and used for a variety of experiments. In parallel, a design for a more advanced LPT that incorporates higher order multipoles will be pursued and later constructed. This multipole trap will allow non-linear lattice elements to be simulated and so broaden considerably the range of experiments that can be conducted. These will include the investigation of resonance crossing in non-linear lattices, a more detailed study of halo formation and the effect of detuning with amplitude. In this paper we report on progress made in the project to date and future plans.
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WEPWA064	Ionization Cooling Channels in COSY Infinity	emittance, space-charge, simulation, solenoid	2652
	B.T. Loseth, M. Berz MSU, East Lansing, Michigan, USA P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA
	Ionization cooling is a method to reduce the emittance of a beam through the use of absorbers, rf cavities, and strong solenoids for focusing, arranged into a condensed lattice. By tuning lattice parameters, it is possible to construct a staged cooling channel in which the beam emittance is always considerably greater than the minimum value. In the late stages of the cooling channel, space charge effects can become a significant obstacle to further emittance reduction once the beam becomes sufficiently condensed. A method has been implemented in COSY Infinity, a beam dynamics simulation and analysis code, which efficiently and accurately calculates the self-fields of all particles on each other based on a variant of the Fast Multipole Method (FMM). In this paper, we present simulations of a muon ionization cooling channel performed in COSY, utilizing the FMM, benchmarked against G4beamline, a standard code for muon beam analysis, in order to investigate the significance of space charge effects.
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WEPMA020	SIS100 Dipole Field Harmonics and Dynamic Aperture Calculations	dipole, quadrupole, simulation, synchrotron	2795
	C. Omet, E.S. Fischer, G. Franchetti, V. Kornilov, A. Mierau, C. Roux, P. Schnizer, D. Schäfer, S. Sorge, P.J. Spiller, K. Sugita GSI, Darmstadt, Germany
	During the acceptance test of the First of Series (FoS) SIS100 super-ferric dipole, detailed field measurements have been done. The harmonic coefficients have been extracted from these and dynamic aperture simulations have been done which are presented here. Furthermore, geometric precision measurement tools for the magnet have been developed to track down the field errors to geometric errors. Finally, mitigation actions have been taken to reduce these errors during manufacturing to ensure the design beam survival rate in SIS100.
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WEPMA023	Advanced Multipoles and Appropriated Measurement Tools for Field Characterization of SIS100 Magnets	dipole, vacuum, superconducting-magnet, ion	2805
	P. Schnizer, E.S. Fischer, A. Gottsmann, F. Kaether, A. Mierau, H.G. Weiss GSI, Darmstadt, Germany B. Schnizer TUG/ITP, Graz, Austria
	The heavy ion synchrotron SIS100 utilises fast ramped superconducting magnets. Describing and measuring these magnets requires advanced multipoles next to well adapted measurement techniques. We cover briefly the required theory adapted to the measurements, show which designs were available and which decisions had to be taken for measuring curved superconducting magnets. The series of SIS100 dipole magnets is going to be produced. These magnets will be measured at GSI. We present the foreseen field measurement procedure, outline the currently ongoing tests and give our calibration strategy.
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WEPMA040	Magnet Studies for the Accelerator FLUTE at KIT	dipole, experiment, linac, simulation	2849
	S. Hillenbrand, A. Bernhard, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Sauter, S. Schott, M. Schuh, S. Schulz, M. Weber, P. Wesolowski, C. Widmann KIT, Karlsruhe, Germany
	At KIT we are currently constructing the compact linear accelerator FLUTE (Ferninfrarot Linac Und Test Experiment). This 41 MeV machine is aimed at accelerator physics and synchrotron radiation research, using ultra-short electron bunches. The electrons are generated at a photo-cathode using picosecond long UV laser pulses. A magnetic chicane is used to compress the bunches longitudinally to a few femtoseconds. This contribution describes both the magnet design, in particular the optimization of the chicane dipoles based on finite element method (FEM) simulations, as well as the implementation of a magnet measurement system.
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WEPMN007	Research Development of High Precision Installation and Alignment System for HEPS	alignment, quadrupole, sextupole, controls	2924
	L. Wu, S.Y. Chen, C. H. Li, H. Qu, H.J. Wang, X.L. Wang IHEP, Beijing, People's Republic of China
	High Energy Photon Source (HEPS) is a proposed 6 GeV third generation light source with high brightness and ultra-low emittance. Because the measurement error of the traditional optical survey method in the girder and magnet installation can’t meet the tight alignment tolerance, the installation and alignment will not only rely on laser tracker and some other optical survey instruments. So HEPS is developing the research of high precision installation and alignment system which is consists of the design of auto-tuning girder based on beam alignment and research of vibrating wire alignment system based on magnetic measurement. This paper introduces the research development of installation and alignment system in storage ring of HEPS.
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WEPTY019	Transverse Field Perturbation For PIP-II SRF Cavities	quadrupole, cavity, linac, dipole	3302
	P. Berrutti, T.N. Khabiboulline, V.A. Lebedev, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359 Proton Improvement Plan II (PIP-II) consists in a plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H⁻ ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. Five cavity types, operating at three different frequencies 162.5, 325 and 650 MHz, provide acceleration to 800 MeV. This paper presents the studies on transverse field perturbation on particle dynamic for all the superconducting cavities in the linac. The effects studied include quadrupole defocusing for coaxial resonators, and dipole kick due to couplers for elliptical cavities. A multipole expansion has been performed for each of the cavity designs including effects up to octupole.
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WEPWI006	Dither Coils for the SuperKEKB Fast Collision Feedback System	vacuum, feedback, collider, coupling	3500
	U. Wienands, S.D. Anderson, S.M. Gierman, M. Kosovsky, C.M. Spencer, M.K. Sullivan SLAC, Menlo Park, California, USA Y. Funakoshi, M. Masuzawa, T. Oki KEK, Ibaraki, Japan
	Funding: Work supported in part by US DOE and in part by the US-Japan collaboration agreement. The collision feedback system for the SuperKEKB electron-positron collider at KEK will employ a dither feedback with a roughly 100 Hz excitation frequency to generate a signal proportional to the offset of the two beams. The excitation will be provided by a local bump across the interaction point (IP) that is generated by a set of eight air-core solid-wire magnet coil assemblies, each of which provides a horizontal and/or vertical deflection of the beam, to be installed around the vacuum system of the SuperKEKB Low Energy Ring. The design of the coils was challenging as large antechambers had to be accommodated and a 0.1% relative field uniformity across a good-field region of ±1 cm was aimed for, while keeping reasonable dimensions of the coils. This led to non-symmetric, non-flat designs of the coils. The paper describes the magnetic design and the method used to calculate the magnetic field of the coils, the mechanical design and the field measurement results. Tracking in the lattice model has indicated acceptable performance.
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WEPWI034	Effects of Crab Cavities' Multipole Content in an Electron-Ion Collider	dipole, sextupole, proton, cavity	3561
	A. Castilla, J.R. Delayen, T. Satogata ODU, Norfolk, Virginia, USA A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata JLab, Newport News, Virginia, USA A. Castilla DCI-UG, León, Mexico
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The impact on the beam dynamics of the Medium Energy Electron-Ion Colider (MEIC) due to the multipole content of the 750 MHz crab cavity was studied using thin multipole elements for 6D phase space particle tracking in ELEGANT. Target values of the sextupole component for the cavity’s field expansion were used to perform preliminary studies on the proton beam stability when compared to the case of pure dipole content of the rf kicks. Finally, important effects on the beam sizes due to non-linear components of the crab cavities’ fields were identified and some criteria for their future study were proposed.
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WEPWI035	Beam Dynamics Studies of 499 MHz Superconducting RF-Dipole Deflecting Cavity System	cavity, dipole, emittance, superconducting-RF	3564
	S.U. De Silva, K.E. Deitrick, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA
	A 499 MHz deflecting cavity has been designed as a three-way beam spreader to separate an electron beam into 3 beams. The rf tests carried out on the superconducting rf-dipole cavity have demonstrated that a transverse voltage of 4.2 MV can be achieved with a single cavity. This paper discusses the beam dynamics on a deflecting structure operating in continuous-wave mode with a relativistic beam. The study includes the analysis on emittance growth, energy spread, and change in bunch size including effects due to field non-uniformities.
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THPF020	Upgrade of the HSI-RFQ at GSI to Fulfill the FAIR Requirements	rfq, simulation, linac, brilliance	3727
	M. Baschke, H. Podlech IAP, Frankfurt am Main, Germany W.A. Barth GSI, Darmstadt, Germany
	In Darmstadt/Germany the existing accelerator facility GSI is expanding to one of the biggest joint research projects worldwide: FAIR, a new antiproton and ion research facility with so far unmatched intensities and quality. The existing accelerators will be used as pre-accelerators and therefor need to be upgraded. In a first step the 36 MHz-HSI-RFQ for high current beams will get new electrodes to fulfill the FAIR requirements. First simulation results for capacity and multipole momentums will be presented.
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THPF047	New Series of RFQ Vane Shapes	acceleration, focusing, quadrupole, rfq	3808
	Y. Iwashita, Y. Fuwa Kyoto ICR, Uji, Kyoto, Japan
	New series of RFQ vane shapes are under investigation by introducing more terms in addition to the two term potential. Because they can incorporate with the feature of the trapezoidal shape modulation with less multipole components, higher acceleration efficiency is expected. The simulation study will be presented.
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THPF137	Beam Dynamics Effects of High Order Multipoles in Non-Axisymmetric Superconducting RF Cavities	sextupole, linac, octupole, lattice	4045
	Z.Q. He, J. Wei, Y. Zhang FRIB, East Lansing, Michigan, USA
	Funding: The work is supported by the U.S. National Science Foundation under Grant No. PHY-11-02511, and the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. Non-axisymmetric superconducting RF cavities have been widely used in accelerator facilities. Because of the geometry, electric and magnetic multipole components, including steering terms, quadrupole terms, and higher order terms, would arise and have potential effects on beam dynamics. In this paper, we start with a simple linac periodic structure to study the effects of higher order terms. The action is defined as a figure of merit to quantify the effects. After that, we move to a more realistic situation of FRIB linac segment 1 (LS1). Multipole terms of quarter wave resonators (QWRs) are firstly calculated using multipole expansion scheme. Then, the scheme is tested using the FRIB linac lattice with QWRs, and the effects of higher order terms on FRIB LS1 are estimated.
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Paper

Title

Other Keywords

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MOBC1

Towards Ultra-Low β^* in ATF2

optics, octupole, collider, linear-collider

38

M. Patecki, A.V. Aloev, D.R. Bett, M. Modena, R. Tomás
CERN, Geneva, Switzerland
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
E. Marín, G.R. White
SLAC, Menlo Park, California, USA

The Accelerator Test Facility 2 (ATF2) has already demonstrated the feasibility of Final Focus Systems based on the local chromaticity correction scheme and its focusing capabilities by reaching a vertical beam size at the virtual Interaction Point (IP) of less than 50 nm. The value of the chromaticity in ATF2 is comparable with the expected chromaticity in ILC, but 4 times lower than in a design of CLIC. ATF2 gives the unique possibility to test operation at CLIC chromaticity values by reducing the vertical beta function at the IP by a factor of 4 (the inverse proportionality of chromaticity with beta function value at IP is assumed). The experience collected in this way would be beneficial for both ILC and CLIC projects. Simulations show that the multipolar errors and Final Doublet fringe fields spoil the IP beam sizes at ATF2. Either increasing a value of the horizontal beta function or installing a pair of octupole magnets mitigate the impact of these aberrations. This paper summarizes the studies towards the realization of the ultra-low β^* optics in ATF2 and reports on the progress of the construction of the octupoles.

Slides MOBC1 [1.566 MB]

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MOPWA016

Increasing the Dynamic and Momentum Apertures of the ThomX Ring by Means of Octupole Correctors

sextupole, octupole, resonance, dipole

121

J.F. Zhang, P. Bambade, A. Faus-Golfe, H. Monard
LAL, Orsay, France
A. Faus-Golfe
IFIC, Valencia, Spain
A. Loulergue
SOLEIL, Gif-sur-Yvette, France

Funding: Work is supported by ANR-10- EQPX-51 and ANR-11-IDEX-0003-02, and also by grants from Region Ile-de-France.
The electron ring of the compact Compton-backscattering X-ray source ThomX which is being built at LAL featured with a small circumference of 18 meters and a low beam energy 50-70 MeV, and its long term single particle dynamics is dominated by the non linear effects in the transverse and longitudinal planes. In this paper, we study the feasibilities to reduce the sextupole resonances and then increase the dynamic aperture and momentum aperture of the ThomX ring, using octupoles correctors.

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MOPWA033

Yacs - A New 2.5D FEM Eigenmode Solver for Axisymmetric RF-Structures

cavity, dipole, quadrupole, software

175

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

Funding: Work supported by the BMBF under contract no. 05K13PEB
Most feasibility studies for modern accelerator concepts, including superconducting multicell RF-cavity-resonators in circular accelerators, depend on computing a large number of eigenmode frequencies and field patterns to obtain typical figures of merit. This task includes computational intensive numerical studies. To obtain the full eigenfrequency spectra most of these studies are performed in 3D, require a great amount of computation resources and thus are limited to a few hundred or thousand eigenmodes. To overcome this issue, some codes make use of the axisymmetric geometry of most of the RF-cavity-resonator structures and solve the problem in 2D. Solving in 2D however reduces the eigenmode spectra to eigenmodes with no azimuthal dependencies (so called monopole-modes). Due to the lack of freely available and easy to use 2.5D eigenmode solvers which are able to solve for the full 3D field in a reduced 2.5 dimensional problem, we developed yet another cavity solver (Yacs), a simple FEM based solver capable of solving for the full 3D eigenmodes of axisymmetric problems while only requiring a fraction of the computation resources required by most modern 3D codes.

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MOPWA065

Uniformization of the Transverse Beam Profile by a New Type Nonlinear Magnet

octupole, target, dipole, simulation

272

G. Gu, W.B. Liu
IHEP, Beijing, People's Republic of China

The uniform particle beam is desirable in many beam applications. One method to get this type of beam distribution is using octupoles, but loss of particles in the halo will be produced by this method. To reduce the beam loss, a new type of magnet is proposed in this paper. The field in the middle region of the new type magnet is similar to the octupole magnet field, but the rate of rise decline quickly in the edge. So that the particle in the edge experience a lower magnet field, and this would result in less particle loss. We also add a mechanical structure on the new type magnet to make it possible to adjust the size of middle region. So that the magnet can adapt to different transverse dimensions of the beam, and this would further reduce particle loss. Some numerical simulations have been done respectively with octuples and the new type of magnet. The simulation results show that the new type of magnet could get the uniform distribution of particle beam with less particle loss. We are processing a magnet now, and an experiment to test the magnet will be arranged on CPHS.

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MOPJE075

Tracking Through Analytic Quadrupole Fringe Fields With GPT

quadrupole, simulation, space-charge, interface

489

S.B. van der Geer, M.J. de Loos
Pulsar Physics, Eindhoven, The Netherlands
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

In the early design stages it is customary to work with a highly simplified analytic model to describe the beam line. Dipoles and quadrupoles are often based on hard-edged approximations. This is not only unrealistic, it also significantly slows down time-domain spacecharge tracking codes such as the General Particle Tracer (GPT) code. The underlying reason for the poor performance is that despite the fact that the simple hard-edged field equations are fast to evaluate, they force the integration process to use excessively small step sizes near the fields discontinuities in order to achieve the desired accuracy. In other worlds, the apparently simple equations turn out to be the most difficult ones to evaluate numerically. An obvious solution is to switch to field-maps, but this is not practical in the early design stages. In this contribution we show a new solution implemented in the GPT code based on analytical expressions for the fringes where the transverse size of the magnet is properly taken into account. In addition to producing more realistic results, the smooth fields increase tracking speed by over an order of magnitude for typical test cases.

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MOPMA050

Smooth Fast Multipole Method for Space Charge Tracking: An Alternate to Particle-In-Cell

space-charge, simulation, framework, emittance

663

A.J. Gee, B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA
B. Erdelyi
ANL, Argonne, USA

The fast multipole method (FMM) algorithm was developed by Greengard and Rokhlin in 1987 *. As one of the top ten algorithms of the 20th century, it has been applied in a wide range of fields. The FMM complexity is O(N), where N is the number of articles, allowing for large-scale simulations. However, it includes all the two-body collisional forces, in contrast to other methods such as the popular particle in-cell (PIC) methods. While collisionality can be very important, many applications require only the mean field effects. PIC is frequently used in this regime. Due to recent concerns of unphysical effects of grids, interpolation and other approximations in PIC codes, an alternative based on different underlying assumptions would prove enlightening. For these cases, a smoothed or softened FMM using a Plummer-like smoothing parameter holds much promise. Unfortunately, the original FMM based on analytic expansions of the 1/r-like potentials does not allow for Plummer softening. We present our new soft-FMM employing differential algebras (DA) to obtain the modified expansions. We also compare the performance of the smoothed DA-FMM with examples from PIC simulations.
* L. Greengard and V. Rokhlin. “A fast algorithm for particle simulations".

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MOPMN021

NSLS-II Storage Ring BPM Button Development

vacuum, impedance, simulation, storage-ring

748

A. Blednykh, B. Bacha, G. Bassi, W.X. Cheng, C. Hetzel, B.N. Kosciuk, D. Padrazo, O. Singh
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract DE-AC02-98CH10886
The NSLS-II BPM Button design and its development process have been described. Subjects discussed include BPM Button impedance optimization, design and construction, production, BPM Button selection and a first temperature measurements at 200mA average current within 1200 bunches.

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TUAD1

Magnet Design and Control of Field Quality for TPS Booster and Storage Rings

quadrupole, dipole, sextupole, vacuum

1370

J.C. Jan, C.H. Chang, C.-T. Chen, H.H. Chen, Y.L. Chu, M.-H. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, G.-H. Luo, I.C. Sheng, C.S. Yang, Y.T. Yu
NSRRC, Hsinchu, Taiwan

High-quality and very demanding magnets were designed, fabricated, field quality controlled and installed in the Taiwan Photon Source (TPS). The Storage Ring (SR) lattice is based on double-bend achromat structure with 1.6 nm-rad emittance and slight dispersion in straight sections. The fabrication and field measurement of these magnets were completed in Oct. 2013. The first synchrotron light from TPS storage ring, without applying any corrector at 3 GeV, was observed on Dec. 31, 2014. It indicates that the profile precision and field quality of magnets, and girders alignment reach world class standard. The integral multipoles components of the 240 SR quadrupole and 168 SR sextupole magnets conform to strict specifications. The maximum offset of measured mechanical center in magnets is better than 0.01 mm after feet shimming. The magnetic center offset of the magnets is within 0.02 mm inspected by rotating-coil method. The magnets’ field quality of booster’s pure quadrupole and combined-function quadrupole were accepted according to the errors specifications from beam dynamics and also in the beam commissioning. A permeability study of vacuum chamber was implemented during the booster ring hardware testing. The magnetic field of magnets is distorted by the permeability of vacuum chamber. Study of multipole errors due to magnetized vacuum chamber inside the magnet will be discussed.

Slides TUAD1 [2.698 MB]

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TUPWA014

Influence of errors on the ESRF Upgrade Lattice

survey, lattice, dynamic-aperture, alignment

1426

S.M. Liuzzo, J.C. Biasci, N. Carmignani, L. Farvacque, G. Gatta, G. Le Bec, D. Martin, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

To determine the tolerable alignment and magnetic errors for the ESRF upgrade, we study their influence on Touschek lifetime and dynamic aperture. The correction of each set of errors studied is performed with a commissioning-like procedure, from the search for a closed orbit to the correction of resonance driving terms. Each kind of error is studied independently for each relevant family of magnets. The tolerable values deduced from the analysis are within the practical limits. The impact of the measured and simulated survey errors is also considered, defining the position of the currently installed lattice as the one of least impact for the realignment of X-ray beamlines.

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TUPJE005

Development of Pulsed Multipole Magnet for Aichi SR Storage Ring

storage-ring, electron, injection, synchrotron

1616

K. Ito, M. Hosaka, A. Mano, T. Takano, Y. Takashima
Nagoya University, Nagoya, Japan
K. Hayashi, M. Katoh
UVSOR, Okazaki, Japan
N. Yamamoto
KEK, Ibaraki, Japan

The Aichi synchrotron radiation (Aichi SR) center is an industrial oriented synchrotron light source facility. The electron energy and circumference of the storage ring are 1.2 GeV and 72 m. The natural emittance is 53 nm-rad. Since the pulsed multipole injection scheme provides great advantages for relatively smaller SR rings*, we are developing a pulsed multipole injection system for Aichi SR storage ring. In this system, it is essential to minimize the perturbation to the stored beam. To realize the required performances, we have to minimize the residual field at stored beam position, taken into account the field generated by the copper current lead of the input terminal. In addition, we carried out the analytical calculation to estimate the magnet field due to the current lead and optimized the geometrical structure of them. Construction of the multipole magnet will be completed in March 2015 and the field measurement will be carried out in April. In this presentation, we report the detail of the magnet design and the measurement results of pulsed magnetic field for the manufactured magnet.
* N. Yamamoto, et. al., NIM A 767, 26-33 (2014)

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TUPJE046

Investigation of the Injection Scheme for SLS 2.0

injection, kicker, lattice, booster

1720

Á. Saá Hernández, M. Aiba
PSI, Villigen PSI, Switzerland

SLS2, an upgrade of the Swiss Light Source (SLS), aiming at a natural horizontal emittance in the range of 100 pm is planned and under study. This will be achieved by replacing the current magnet lattice of the electron storage ring by a new multibend achromat magnet lattice, while reusing the injector chain and most of the existing infrastructures. The new low emittance ring will impose more restrictive constraints on injection due to a smaller machine aperture and a very compact lattice, dominated by non-linearities. We performed a study to find the optimum injection scheme for SLS2 among the conventional and more advanced schemes; namely multipole kicker injection (off-axis and also on-axis matched to the off-momentum closed orbit) and longitudinal injection.

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TUPJE063

Hybrid Seven-Bend-Achromat Lattice for the Advanced Photon Source Upgrade

lattice, emittance, injection, sextupole

1776

M. Borland, V. Sajaev, Y. Sun
ANL, Argonne, Ilinois, 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.
A hybrid seven-bend-achromat lattice has been designed for the APS upgrade. We describe the design goals, constraints, and methodology, including the choice of beam energy. Magnet strength and spacing is compatible with engineering designs for the magnets, diagnostics, and vacuum system. Dynamic acceptance and local momentum acceptance were simulated using realistic errors, then used to assess workable injection methods and predict beam lifetime. Predicted brightness is two to three orders of magnitude higher than the existing APS storage ring. Pointers are provided to other papers in this conference that cover subjects in more detail.

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TUPTY054

RF Design of the CLIC Structure Prototype Optimized for Manufacturing from Two Halves

linac, wakefield, simulation, collider

2147

H. Zha, A. Grudiev
CERN, Geneva, Switzerland
V.A. Dolgashev
SLAC, Menlo Park, California, USA

We present the RF design of a 12GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype. The structure is made from two longitudinally symmetric halves. The main manufacturing process of each half is precision milling. The structure uses the same iris dimensions as the CLIC-G structure but the cell shape is optimized for milling. The geometry is optimized to reduce the surface electric and magnetic fields and the modified Poynting vector. This design can potentially reduce fabrication cost.

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WEPWA041

Plans for a Linear Paul Trap at Rutherford Appleton Laboratory

quadrupole, plasma, ion, resonance

2590

D.J. Kelliher, S. Machida, D.C. Plostinar, C.R. Prior, S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

For over a decade, Linear Paul Traps (LPT) have been used in the study of accelerator beam dynamics. LPT studies exploit the similarity of the Hamiltonian with that of a beam in a quadrupole channel while having advantages in the flexibility of parameter choice, compactness and low cost. In collaboration with Hiroshima University, LPT research planned at STFC Rutherford Appleton Laboratory in the UK aims to investigate a range of topics including resonance crossing, halo formation, long-term stability studies and space-charge effects. Initially, a conventional quadrupole-based LPT will be built at RAL and used for a variety of experiments. In parallel, a design for a more advanced LPT that incorporates higher order multipoles will be pursued and later constructed. This multipole trap will allow non-linear lattice elements to be simulated and so broaden considerably the range of experiments that can be conducted. These will include the investigation of resonance crossing in non-linear lattices, a more detailed study of halo formation and the effect of detuning with amplitude. In this paper we report on progress made in the project to date and future plans.

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WEPWA064

Ionization Cooling Channels in COSY Infinity

emittance, space-charge, simulation, solenoid

2652

B.T. Loseth, M. Berz
MSU, East Lansing, Michigan, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Ionization cooling is a method to reduce the emittance of a beam through the use of absorbers, rf cavities, and strong solenoids for focusing, arranged into a condensed lattice. By tuning lattice parameters, it is possible to construct a staged cooling channel in which the beam emittance is always considerably greater than the minimum value. In the late stages of the cooling channel, space charge effects can become a significant obstacle to further emittance reduction once the beam becomes sufficiently condensed. A method has been implemented in COSY Infinity, a beam dynamics simulation and analysis code, which efficiently and accurately calculates the self-fields of all particles on each other based on a variant of the Fast Multipole Method (FMM). In this paper, we present simulations of a muon ionization cooling channel performed in COSY, utilizing the FMM, benchmarked against G4beamline, a standard code for muon beam analysis, in order to investigate the significance of space charge effects.

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WEPMA020

SIS100 Dipole Field Harmonics and Dynamic Aperture Calculations

dipole, quadrupole, simulation, synchrotron

2795

C. Omet, E.S. Fischer, G. Franchetti, V. Kornilov, A. Mierau, C. Roux, P. Schnizer, D. Schäfer, S. Sorge, P.J. Spiller, K. Sugita
GSI, Darmstadt, Germany

During the acceptance test of the First of Series (FoS) SIS100 super-ferric dipole, detailed field measurements have been done. The harmonic coefficients have been extracted from these and dynamic aperture simulations have been done which are presented here. Furthermore, geometric precision measurement tools for the magnet have been developed to track down the field errors to geometric errors. Finally, mitigation actions have been taken to reduce these errors during manufacturing to ensure the design beam survival rate in SIS100.

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WEPMA023

Advanced Multipoles and Appropriated Measurement Tools for Field Characterization of SIS100 Magnets

dipole, vacuum, superconducting-magnet, ion

2805

P. Schnizer, E.S. Fischer, A. Gottsmann, F. Kaether, A. Mierau, H.G. Weiss
GSI, Darmstadt, Germany
B. Schnizer
TUG/ITP, Graz, Austria

The heavy ion synchrotron SIS100 utilises fast ramped superconducting magnets. Describing and measuring these magnets requires advanced multipoles next to well adapted measurement techniques. We cover briefly the required theory adapted to the measurements, show which designs were available and which decisions had to be taken for measuring curved superconducting magnets. The series of SIS100 dipole magnets is going to be produced. These magnets will be measured at GSI. We present the foreseen field measurement procedure, outline the currently ongoing tests and give our calibration strategy.

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WEPMA040

Magnet Studies for the Accelerator FLUTE at KIT

dipole, experiment, linac, simulation

2849

S. Hillenbrand, A. Bernhard, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Sauter, S. Schott, M. Schuh, S. Schulz, M. Weber, P. Wesolowski, C. Widmann
KIT, Karlsruhe, Germany

At KIT we are currently constructing the compact linear accelerator FLUTE (Ferninfrarot Linac Und Test Experiment). This 41 MeV machine is aimed at accelerator physics and synchrotron radiation research, using ultra-short electron bunches. The electrons are generated at a photo-cathode using picosecond long UV laser pulses. A magnetic chicane is used to compress the bunches longitudinally to a few femtoseconds. This contribution describes both the magnet design, in particular the optimization of the chicane dipoles based on finite element method (FEM) simulations, as well as the implementation of a magnet measurement system.

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WEPMN007

Research Development of High Precision Installation and Alignment System for HEPS

alignment, quadrupole, sextupole, controls

2924

L. Wu, S.Y. Chen, C. H. Li, H. Qu, H.J. Wang, X.L. Wang
IHEP, Beijing, People's Republic of China

High Energy Photon Source (HEPS) is a proposed 6 GeV third generation light source with high brightness and ultra-low emittance. Because the measurement error of the traditional optical survey method in the girder and magnet installation can’t meet the tight alignment tolerance, the installation and alignment will not only rely on laser tracker and some other optical survey instruments. So HEPS is developing the research of high precision installation and alignment system which is consists of the design of auto-tuning girder based on beam alignment and research of vibrating wire alignment system based on magnetic measurement. This paper introduces the research development of installation and alignment system in storage ring of HEPS.

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WEPTY019

Transverse Field Perturbation For PIP-II SRF Cavities

quadrupole, cavity, linac, dipole

3302

P. Berrutti, T.N. Khabiboulline, V.A. Lebedev, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
Proton Improvement Plan II (PIP-II) consists in a plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H⁻ ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. Five cavity types, operating at three different frequencies 162.5, 325 and 650 MHz, provide acceleration to 800 MeV. This paper presents the studies on transverse field perturbation on particle dynamic for all the superconducting cavities in the linac. The effects studied include quadrupole defocusing for coaxial resonators, and dipole kick due to couplers for elliptical cavities. A multipole expansion has been performed for each of the cavity designs including effects up to octupole.

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WEPWI006

Dither Coils for the SuperKEKB Fast Collision Feedback System

vacuum, feedback, collider, coupling

3500

U. Wienands, S.D. Anderson, S.M. Gierman, M. Kosovsky, C.M. Spencer, M.K. Sullivan
SLAC, Menlo Park, California, USA
Y. Funakoshi, M. Masuzawa, T. Oki
KEK, Ibaraki, Japan

Funding: Work supported in part by US DOE and in part by the US-Japan collaboration agreement.
The collision feedback system for the SuperKEKB electron-positron collider at KEK will employ a dither feedback with a roughly 100 Hz excitation frequency to generate a signal proportional to the offset of the two beams. The excitation will be provided by a local bump across the interaction point (IP) that is generated by a set of eight air-core solid-wire magnet coil assemblies, each of which provides a horizontal and/or vertical deflection of the beam, to be installed around the vacuum system of the SuperKEKB Low Energy Ring. The design of the coils was challenging as large antechambers had to be accommodated and a 0.1% relative field uniformity across a good-field region of ±1 cm was aimed for, while keeping reasonable dimensions of the coils. This led to non-symmetric, non-flat designs of the coils. The paper describes the magnetic design and the method used to calculate the magnetic field of the coils, the mechanical design and the field measurement results. Tracking in the lattice model has indicated acceptable performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI006

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WEPWI034

Effects of Crab Cavities' Multipole Content in an Electron-Ion Collider

dipole, sextupole, proton, cavity

3561

A. Castilla, J.R. Delayen, T. Satogata
ODU, Norfolk, Virginia, USA
A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata
JLab, Newport News, Virginia, USA
A. Castilla
DCI-UG, León, Mexico

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The impact on the beam dynamics of the Medium Energy Electron-Ion Colider (MEIC) due to the multipole content of the 750 MHz crab cavity was studied using thin multipole elements for 6D phase space particle tracking in ELEGANT. Target values of the sextupole component for the cavity’s field expansion were used to perform preliminary studies on the proton beam stability when compared to the case of pure dipole content of the rf kicks. Finally, important effects on the beam sizes due to non-linear components of the crab cavities’ fields were identified and some criteria for their future study were proposed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI034

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WEPWI035

Beam Dynamics Studies of 499 MHz Superconducting RF-Dipole Deflecting Cavity System

cavity, dipole, emittance, superconducting-RF

3564

S.U. De Silva, K.E. Deitrick, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA

A 499 MHz deflecting cavity has been designed as a three-way beam spreader to separate an electron beam into 3 beams. The rf tests carried out on the superconducting rf-dipole cavity have demonstrated that a transverse voltage of 4.2 MV can be achieved with a single cavity. This paper discusses the beam dynamics on a deflecting structure operating in continuous-wave mode with a relativistic beam. The study includes the analysis on emittance growth, energy spread, and change in bunch size including effects due to field non-uniformities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI035

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THPF020

Upgrade of the HSI-RFQ at GSI to Fulfill the FAIR Requirements

rfq, simulation, linac, brilliance

3727

M. Baschke, H. Podlech
IAP, Frankfurt am Main, Germany
W.A. Barth
GSI, Darmstadt, Germany

In Darmstadt/Germany the existing accelerator facility GSI is expanding to one of the biggest joint research projects worldwide: FAIR, a new antiproton and ion research facility with so far unmatched intensities and quality. The existing accelerators will be used as pre-accelerators and therefor need to be upgraded. In a first step the 36 MHz-HSI-RFQ for high current beams will get new electrodes to fulfill the FAIR requirements. First simulation results for capacity and multipole momentums will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF020

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THPF047

New Series of RFQ Vane Shapes

acceleration, focusing, quadrupole, rfq

3808

Y. Iwashita, Y. Fuwa
Kyoto ICR, Uji, Kyoto, Japan

New series of RFQ vane shapes are under investigation by introducing more terms in addition to the two term potential. Because they can incorporate with the feature of the trapezoidal shape modulation with less multipole components, higher acceleration efficiency is expected. The simulation study will be presented.

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THPF137

Beam Dynamics Effects of High Order Multipoles in Non-Axisymmetric Superconducting RF Cavities

sextupole, linac, octupole, lattice

4045

Z.Q. He, J. Wei, Y. Zhang
FRIB, East Lansing, Michigan, USA

Funding: The work is supported by the U.S. National Science Foundation under Grant No. PHY-11-02511, and the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Non-axisymmetric superconducting RF cavities have been widely used in accelerator facilities. Because of the geometry, electric and magnetic multipole components, including steering terms, quadrupole terms, and higher order terms, would arise and have potential effects on beam dynamics. In this paper, we start with a simple linac periodic structure to study the effects of higher order terms. The action is defined as a figure of merit to quantify the effects. After that, we move to a more realistic situation of FRIB linac segment 1 (LS1). Multipole terms of quarter wave resonators (QWRs) are firstly calculated using multipole expansion scheme. Then, the scheme is tested using the FRIB linac lattice with QWRs, and the effects of higher order terms on FRIB LS1 are estimated.

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