IPAC2012 - List of Keywords (multipole)

Paper	Title	Other Keywords	Page
MOPPC020	Field Tolerances for the Triplet Quadrupoles of the LHC High Luminosity Lattice	quadrupole, dynamic-aperture, target, lattice	169
	Y. Jiao, Y. Cai, Y. Nosochkov, M.-H. Wang SLAC, Menlo Park, California, USA R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh CERN, Geneva, Switzerland
	Funding: This work is supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP). It has been proposed to implement an Achromatic Telescopic Squeezing (ATS) scheme* in the high luminosity LHC lattice to reduce the beta functions at the Interaction Points (IP) up to a factor of 8. As a consequence, the nominal 4.5-km peak beta functions reached in the inner triplets at collision will be increased by the same factor. This therefore justifies the installation of new, larger aperture superconducting triplet quadrupoles. These higher beta functions will enhance the effects of the triplet quadrupole field errors leading to smaller beam dynamic aperture. To maintain the acceptable dynamic aperture, the effects of the triplet multipole field errors must be re-evaluated, thus specifying new tolerances. Such a study has been performed for the so-called “4444” collision optics of the ATS scheme, where the IP beta functions are reduced by a factor of 4 in both planes with respect to a pre-squeezed value of 60 cm at two collision points. The dynamic aperture calculations were performed using SixTrack. The impact on the triplets’ field quality is studied and presented in details. * S. Fartoukh, “An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade”, Proc. of IPAC11, p. 2088 (2011).

MOPPC024	Modelling of the AGS Using Zgoubi - Status	simulation, optics, closed-orbit, coupling	181
	F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, V. Schoefer, N. Tsoupas BNL, Upton, Long Island, New York, USA
	A computer model, based on the ray-tracing code Zgoubi, is being developed in view of on-line simulation of the RHIC injector AGS, and of beam and spin dynamics simulations and studies in the presence of the cold and warm helical partial snakes. A status of this work is given here.

MOPPC053	Modeling of Bending Magnets for SIRIUS	dipole, simulation, lattice, sextupole	250
	X.R. Resende, R. Basílio, L. Liu, P.P. Sanchez, G. Tosin LNLS, Campinas, Brazil
	The new Brazilian synchrotron source, Sirius, will be a 3 GeV storage ring with a triple bend lattice with a minimum emittance of 1.7 nm rad. The ring dipoles are excited with permanent magnets. The middle bend has a small 1.4 degree slice in its center with 1.94 T field and serve as an additional hard X-ray source with critical energy of 11.6 keV. Other bending magnets have low 0.50 T field with gradients, allowing for a further emittance reduction. The bending slice shows a longitudinal profile with no uniform field plateau and with long-range fringe fields which are coupled with the fields of neighbouring dipoles. To take into account the interaction of the field-intersecting dipoles, realistic 3D models of the magnets have been created and their field configuration solved using finite element techniques. Field maps calculated from the 3D magnet models were used for the construction of segmented models of bend elements in beam dynamics codes.

MOPPC057	Some Comments to Magnetic Field Representation for Beam Dynamic Calculations	dipole, quadrupole, vacuum, resonance	262
	P. Schnizer, E.S. Fischer GSI, Darmstadt, Germany A. Mierau TEMF, TU Darmstadt, Darmstadt, Germany B. Schnizer TUG/ITP, Graz, Austria
	Machines with high currents and small apertures, as used for SIS100 of the FAIR project, require a sincere understanding of the resonances excited by the magnetic field distortions; typically performed by tracking codes. These codes model the field errors using a Taylor Series approximation of the field quality at the track of the ideal particle. The path of the particle within the elliptic aperture of the dipole is curved; thus the standard approach of using plane circular multipoles fails to model the real symmetry of the magnetic field, an important feature of effective field description for beam loss calculations. Therefore toroidal elliptic multipoles were developed which allow describing the magnetic field concisely in an elliptic vacuum chamber in curved dipoles and quadrupoles. In this talk we present the appropriate description and its limitation, illustrate their usefullness based on the static and transient magnetic field measurements of the first curved SIS100 dipole next to the SIS18 dipole.

MOPPC073	Improvements in the PLACET Tracking Code	simulation, ground-motion, linac, alignment	301
	A. Latina, E. Adli, D. Schulte, J. Snuverink CERN, Geneva, Switzerland B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. It has an interface based on both Tcl/Tk and Octave to provide maximum flexibility and easy programming of complex scenarios. Recently, new functionality has been added to expand its simulation and tuning capabilities, such as: tools to perform beam-based alignment of non-linear optical systems, possibility to track through the interaction region in presence of external magnetic fields (detector solenoid), higher order imperfections in magnets, better tools for integrated feedback loops. Moreover, self contained frameworks have been created to ease the simulation of CLIC Drive Beam, CLIC Main Beam, and other existing electron machines such as CTF3 and FACET.

MOPPC074	Evolution of MAD-X in the Framework of LHC Upgrade Studies	simulation, optics, luminosity, quadrupole	304
	A. Latina, L. Deniau CERN, Geneva, Switzerland
	The design efforts for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will require significant extensions of the MAD-X code widely used for designing and simulating particles accelerators. For this purpose, several new capabilities have been added to the code, namely the possibility to simulate crab cavities for crossing angle compensation, with their imperfections; the selective introduction of thick quadrupole elements for particles tracking, improving the previous implementation entirely based on thin-lenses; and the upgrade of the interface to SixTrack used for distributed tracking with, e.g., LHC@home. These changes are framed into a global redesign of the MAD-X architecture meant to consolidate its structure, improve its performances, and increase its flexibility. Such improvements are described in details in the present paper.

MOPPC077	Simulation and Analysis of the Beam Signal in Taiwan Photon Source Booster	booster, lattice, betatron, synchrotron	313
	C.C. Chiang, H.-P. Chang, P.J. Chou NSRRC, Hsinchu, Taiwan S.-Y. Lee IUCEEM, Bloomington, Indiana, USA
	The TPS (Taiwan Photon Source) booster is a combined function FODO lattice with six super-periods; the total circumference is 496.8 m. To prepare the analysis tools for beam commissioning, we simulate the TPS booster turn-by-turn BPM data with two programs, MAD-X PTC and Tracy-2.6, which are for both DC (constant beam energy) and AC (beam energy in regular ramping) modes. We analyze the simulation data with MIA (Model Independent Analysis) and ICA (Independent Component Analysis), in order to reconstruct beam parameters like beta function, phase advance, dispersion, etc. We include multipole errors, alignment errors, BPM noises or other noises in simulation, and try to design a good strategy for real data analysis.

MOPPC093	Optimal Fast Multipole Method Data Structures	target, electron, simulation, space-charge	352
	S. Abeyratne, B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA S.L. Manikonda ANL, Argonne, USA
	The Fast Multipole Method (FMM) has been identified as one of the ten most significant numerical algorithms discovered in the 20th century. The FMM guarantees finding fast solutions to many problems in science, such as calculating Coulomb potentials among large number of particles by reducing memory footprint and run time while attaining very high accuracy levels. One important practical issue that we have to solve in implementing a FMM algorithm is organizing large amounts of data, also called data structuring. The non-adaptive FMM is appropriate when the particles are uniformly distributed while the adaptive FMM is most efficient when the distribution is non-uniform. In practice, we typically encounter highly non-uniform 3D particle distributions. This paper summarizes our implementation of a 3D adaptive FMM algorithm data structure setup for non-uniform particle distributions.

MOPPP079	Magnetic Tuning of the APS Wiggler as a Study for Tuning the NSLS-II Damping Wiggler	wiggler, damping, octupole, insertion	747
	I. Vasserman, M. Abliz, E. Gluskin, E. Trakhtenberg, J.Z. Xu ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 A wide variety of tuning techniques has been developed and employed at Advanced Photon Source (APS) in the course of tuning insertion devices for use on the APS storage ring, the APS free electron laser, and in assisting with the LCLS undulator tuning. The tuning requirements for the National Synchrotron Source II (NSLS-II) damping wigglers are very demanding and include limits on the off-midplane field integrals that are new in the repertoire of undulator magnetic tuning. The goal of this study was to assess the applicability of existing tuning techniques to meeting the off-midplane requirements of NSLS-II. Tests were run using an available APS 8.5-cm-period wiggler. In addition to existing techniques, a special new shim design was tested. This report summarizes the results of these tests and shows that the wiggler can be tuned to the required specifications on the midplane over the requested ±15 mm in the horizontal direction. In the vertical direction, however, the specifications could only be met within ±0.5 mm. This falls short of the ±15 mm by ± 3 mm good-field region that is sought by NSLS-II.

TUOAA02	Focusing Charged Particle Beams Using Multipole Magnets in a Beam Transport Line	sextupole, octupole, target, focusing	1062
	Y. Yuri, I. Ishibori, T. Ishizaka, S. Okumura, T. Yuyama JAEA/TARRI, Gunma-ken, Japan
	The intensity distribution of a charged-particle beam is transformed by applying the nonlinear focusing force of a multipole magnet. In this paper, the transformation of the transverse intensity distribution due to the second-order sextupole and third-order octupole focusing force in the beam transport line is explored. As a measure of the distribution transformation induced by the multipole magnets, the beam centroid displacement and the change of the beam size have been analytically derived using the distribution function of the beam. It is numerically verified how the transverse distribution of the beam is transformed by the multipole magnets. As an application of the distribution transformation by nonlinear focusing, a uniform beam can be formed from a Gaussian beam using multipole magnets. The current status and future plan of the experiment on the uniform-beam formation at the cyclotron facility in Japan Atomic Energy Agency will be shown.
	Slides TUOAA02 [2.032 MB]

TUPPC001	Quadrupole Shapes	quadrupole, optics, TRIUMF, controls	1149
	R.A. Baartman TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Traditionally, quadrupoles are shaped to have a constant vertical cross-section. In other words, the poles are cylindrical segments extended in the beam direction and circular or hyperbolic in cross section. At the ends, the poles are simply truncated or sometimes slightly smoothed with a chamfer. Even very short quadrupoles are often this shape. A new shape is derived analytically, and it is demonstrated that this shape yields dramatically smaller aberrations.

TUPPC009	Dihedral Group and Repetitive Achromats with Mirror Symmetric or Mirror Antisymmetric Basic Cell	electron, resonance, focusing, free-electron-laser	1170
	V. Balandin, R. Brinkmann, W. Decking, N. Golubeva DESY, Hamburg, Germany
	Using the group-theoretical point of view for the design of magnetic optical achromats as introduced in, we study in this paper second- and third-order repetitive achromats with a mirror symmetric or mirror antisymmetric basic cell. We also compare these achromats with repetitive achromats designed without internal cell symmetries taken into account. V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Two Cell Repetitive Achromats and Four Cell Mirror Symmetric Achromats, Proceedings of IPAC'10, Kyoto, Japan.

TUPPC042	Effect of Field Errors in Muon Collider IR Magnets on Beam Dynamics	dipole, sextupole, quadrupole, dynamic-aperture	1257
	Y. Alexahin, E. Gianfelice-Wendt, V.V. Kapin Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy In order to achieve peak luminosity of a Muon Collider (MC) in the 10³⁵/cm²/s range very small values of beta-function at the interaction point (IP) are necessary (β^* ~ 5 mm) while the distance from IP to the first quadrupole can not be made shorter than ~6m as dictated by the necessity of detector protection from backgrounds. In the result the beta-function at the final focus quadrupoles can reach 100 km making beam dynamics very sensitive to all kind of errors. In the present report we consider the effects on momentum acceptance and dynamic aperture of multipole field errors in the body of IR dipoles as well as of fringe-fields in both dipoles and quadrupoles in the case of 1.5 TeV (c.o.m.) MC. Analysis shows these effects to be strong but correctable with dedicated multipole correctors.

TUPPC050	Beam Transport and Storage with Cold Neutral Atoms and Molecules	sextupole, solenoid, injection, quadrupole	1281
	P.L. Walstrom, M.D. Di Rosa LANL, Los Alamos, New Mexico, USA
	Funding: US Department of Energy Paramagnetic neutral atoms and molecules are subject to magnetic-field-gradient forces on their magnetic moments. Li atoms and CaH molecules both have an effective magnetic moment of about one Bohr magneton, and in the presence of a strong (~1 T) magnetic field, acquire a Zeeman energy of one of two values, ±μ\|B\|. Particles with positive (negative) energy are repelled by (attracted toward) increasing fields. Li and CaH can be laser-cooled to speeds of tens of m/s and the corresponding magnetic fields needed for transport and injection are on the order of 1 T. The stable stored state is the field-repelled state. Many concepts of accelerator physics apply to our neutral particles. The analog of charge-exchange injection into storage rings is laser-based optical pumping from a field-seeking state to a field-repelled state. The role of dipoles in charged-particle optics is played by quadrupoles in neutral particle optics, and the role of quadrupoles by sextupoles. We present our design and tracking results for a neutral atom/molecule accumulator including an injection chicane with a laser-stimulated state-flip.

TUPPP001	Beam Based Measurements with Superconducting Wigglers at the Canadian Light Source with Applications to Nonlinear Beam Dynamics	wiggler, injection, dynamic-aperture, optics	1599
	W.A. Wurtz, L.O. Dallin, M.J. Sigrist CLS, Saskatoon, Saskatchewan, Canada
	The Canadian Light Source (CLS) employs two superconducting wigglers for the production of hard x-rays. These wigglers cause a large decrease in injection efficiency. While such a decrease is not unexpected due to the large distortion to the linear optics, a correction to the linear optics does not restore injection efficiency. This inability to restore injection is not predicted by a kickmap model of the wiggler. We performed beam based measurements to construct a phenomenological, nonlinear model of the wiggler. Particle tracking with this wiggler model shows that the reduction in dynamic aperture is due to the amplitude dependent tune shift crossing a resonance, even with the linear optics corrected. Moving the tunes allows us to avoid this resonance and measurements at these tunes show that injection efficiency is not greatly affected by the wigglers.

TUPPP011	Simulations of Fringe Fields and Multipoles for the ANKA Storage Ring Bending Magnets	simulation, optics, sextupole, storage-ring	1626
	M. Streichert, M.J. Nasse Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany V. Afonso Rodriguez, A. Bernhard, N. Hiller, E. Huttel, V. Judin, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M. Schwarz, N.J. Smale KIT, Karlsruhe, Germany
	Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320. ANKA is the synchrotron light source of the Karlsruhe Institute of Technology (KIT). With a maximum particle energy of 2.5 GeV, the storage ring lattice consists of 16 bending magnets with a nominal magnetic flux density of 1.5 T. For the beam dynamics simulations the consideration of the fringe fields and multipoles is essential. A reference measurement of the longitudinal magnetic flux density profile of a bending magnet exists for a current of 650 A, corresponding to a particle energy of 2.46 GeV. For lower beam energies where the magnets are no longer close to saturation, however, the exact density profiles may vary significantly. In order to derive fringe fields and multipole components for different beam energies, simulations of the magnetic flux density for different beam energies were conducted using a finite element method (FEM). We present the results of the simulations and demonstrate the improvements of the beam dynamics simulations in AT (Accelerator Toolbox).

TUPPP013	Effects of Multipoles in Dynamic Aperture of the ILSF Storage Ring	dynamic-aperture, sextupole, quadrupole, lattice	1632
	S. Fatehi, E. Ahmadi, F. Saeidi ILSF, Tehran, Iran D. Einfeld CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain H. Ghasem IPM, Tehran, Iran
	Dynamic aperture of a synchrotron light source shrinks to small value due to the multipole errors caused by magnet design. In the ILSF storage ring, the tolerance of magnets has been taken into account in the simulation and sextupole magnets reoptimized to improve the dynamic aperture. This paper yields the evaluated dynamic aperture include of multipole errors.

TUPPR027	Study of Multipolar RF Kicks from the Main Deflecting Mode in Compact Crab Cavities for LHC	cavity, dipole, simulation, coupling	1873
	A. Grudiev, J. Barranco, R. Calaga, R. De Maria, M. Giovannozzi, R. Tomás CERN, Geneva, Switzerland
	A crab cavity system is under design in the frame work of the High Luminosity LHC project. Due to transverse space constraints on one hand and the RF frequency requirements on the other hand, the design of the crab cavities has to be compact. This results in the crab cavity shape being far from axially symmetric and, as a consequence, higher order multipolar components of the main deflecting mode are non-zero. In this paper, multipolar RF kicks from the main deflecting mode have been calculated in the compact crab cavities for LHC. They are compared to the multipolar error in magnetic elements of LHC. The influence of the RF kicks on the beam dynamics has been investigated and possible acceptable tolerances are presented.

TUPPR066	Characterization of Single Particle Dynamics for the International Linear Collider Damping Ring Lattice	damping, emittance, wiggler, lattice	1972
	J.P. Shanks, J.A. Crittenden, M.A. Palmer CLASSE, Ithaca, New York, USA D.L. Rubin Cornell University, Ithaca, New York, USA
	Funding: DOE Award DE-SC0006506 The baseline design for the International Linear Collider damping rings is a 3.2 km circumference racetrack, with 5 GeV beam energy. The transverse damping time is 26 ms and the normalized horizontal emittance 5 mm-mrad. Nearly 60 2.2-m-long superconducting wigglers per ring increase the radiation damping rate by an order of magnitude and reduce horizontal emittance by a factor of 5. We characterize the sensitivity to magnet misalignments and field errors, and establish the minimum numbers of corrector magnets and beam position monitors required for tuning vertical emittance to less than 20 nm-rad. We validate the specified tolerable guide field multipole errors consistent with adequate dynamic aperture. Tune scans are used to identify stable working points. In tracking studies we use a wiggler model based on fits to 3-dimensional field maps.

WEEPPB013	Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR	dipole, quadrupole, octupole, background	2191
	B. Parker, M. Anerella, J. Escallier, A.K. Ghosh, A.K. Jain, A. Marone, P. Wanderer BNL, Upton, Long Island, New York, USA Y. Arimoto, M. Iwasaki, N. Ohuchi, M. Tawada, K. Tsuchiya, H. Yamaoka, Z.G. Zong KEK, Ibaraki, Japan
	Upgrade of the KEKB asymmetric e⁺e⁻ collider for a forty-fold luminosity increase, denoted SuperKEKB, is now underway. For SuperKEKB the beam crossing angle is increased to provide separate focusing channels for the incoming and outgoing electron and positrons beams in new superconducting Interaction Region (IR) magnets. Two functional classes of superconducting corrector magnets are needed to meet SuperKEKB beam optics goals. Dipole, skew-dipole, skew-quadrupole and octupole coil windings will be inserted inside the bores of the main IR quadrupoles to make magnet center alignments, roll adjustments and non-linear optics corrections. A second class of high-order magnetic multipole corrector coils is needed to compensate the non-linear fringe field experienced by the circulating beam that passes just outside the main quadrupole coils that are closest to the Interaction Point (IP). Near the IP there is no space for magnetic yokes or other passive shielding to diminish the fringe field. At the time of this conference the SuperKEKB corrector magnet production will be under way. The SuperKEKB correction coil design and our production technique are reviewed in this paper.

WEPPC044	Multipole Effects Study for Project X Front End Cavities	cavity, quadrupole, linac, focusing	2309
	P. Berrutti, M.H. Awida, I.V. Gonin, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	Effects of RF field asymmetry along with multipoles have been studied in Project X front end cavities. One family of half wave resonators operating at 162.5 and two of spoke resonators operating at 325 MHz have been analysed. HWR and spoke resonators unlike elliptical cavities, do not have axial symmetry, hence a quadrupole perturbation to the beam is present. The purpose of this paper is to explain the approach and the calculation method used to understand and overcome the drawbacks due to the RF field asymmetry.

WEPPC047	Effects of the RF Field Asymmetry in SC Cavities of the Project X	linac, cavity, acceleration, focusing	2318
	I.V. Gonin, M.H. Awida, P. Berrutti, A. Saini, B.G. Shteynas, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA P.N. Ostroumov ANL, Argonne, USA
	The low-energy SCRF section of CW SC linac of Project X starts from Half Wave Resonators (HWR) having operating frequency f=162.5 MHz, optimal β= 0.11 and will accelerate the beam from 2 MeV up to 11 MeV. The preliminary analysis of beam dynamics shows that multipole effects caused by asymmetry of RF fields in HWR cavities aren’t negligible. In this paper we present the analysis of influence of multipole effects on beam dynamics and discuss the possible solutions how to compensate these effects.

WEPPC103	Development of Spoke Cavities for High-velocity Applications	electron, cavity, higher-order-mode, impedance	2456
	C.S. Hopper, J.R. Delayen ODU, Norfolk, Virginia, USA R.G. Olave Old Dominion University, Norfolk, Virginia, USA
	In response to recent interest in alternatives to elliptical cavities for low-frequency, high-velocity applications we have initiated a program for the development of multi-spoke superconducting cavities. We have completed the electromagnetic design for two-spoke cavities operating at 352 and 325 MHz and a design velocity of β = 0.82 and β = 1. We present the results of the optimization, higher order mode (HOM) analysis, multipacting analysis, and an initial multipole expansion study of the fundamental accelerating mode.

WEPPD026	Design and Fabrication of NSLS-II Storage Ring Vacuum Chambers and Components	vacuum, storage-ring, photon, impedance	2558
	H.-C. Hseuh, A.T. Anderson, L. Doom, M.J. Ferreira, C. Hetzel, C. Longo, V. Ravindranath, K. Roy, S.K. Sharma, J.L. Tuozzolo, K. Wilson BNL, Upton, Long Island, New York, USA
	Funding: Work performed under the auspices of U.S. Department of Energy, under contract DE-AC02-98CH10886 The National Synchrotron Light Source II, a 3-GeV, 792-meter circumference, synchrotron radiation facility with ultra-high-flux and brightness, is under construction at Brookhaven National Laboratory. The storage ring vacuum chambers are mainly made of extruded aluminium but with a few made of stainless steel and inconel. The synchrotron radiation from bending magnets is intercepted at discrete photon absorbers made of GlidCop. NEG strips in the ante-chamber provide the distributed pumping, while lumped ion pumps and titanium sublimation pumps at photon absorbers remove the desorbed gas. The complex vacuum system is being assembled and integrated in-house. This paper describes the design and fabrication of both standard and special vacuum chambers, the low impedance RF shielded bellows and the photon absorbers. The vacuum system is now moving into the conditioning, installation and testing phase. Details and experience from the large scale production, testing and lesson learned will also be presented.

WEPPR067	Study of Fundamental Mode Multipolar Kicks in Double- and Single-feed Power Couplers for the CLIC Main Linac Accelerating Structure	linac, simulation, emittance, cavity	3081
	A. Latina, A. Grudiev, D. Schulte CERN, Geneva, Switzerland
	Multipolar kicks from the fundamental mode have been calculated in the CLIC baseline accelerating structure with double–feed input and output power couplers. The influence of such multipolar kicks on the main linac beam dynamics has been investigated. Furthermore, an alternative design of the couplers with single-feed has been studied and compared with the double-feed. Such an alternative would significantly simplify the waveguide system of the main linac but potentially introduce an harmful dipolar kick from the fundamental mode. The geometry of the coupler has been optimized in order to minimize such a dipolar kick and keep it below threshold levels determined with beam dynamics simulations. Influence of the higher order multipoles has been investigated as well and acceptable levels have been determined.

THPPD001	Stretched-wire Measurements of Small Bore Multipole Magnets	quadrupole, permanent-magnet, simulation, alignment	3500
	G. Lebec, J. Chavanne, C. Penel ESRF, Grenoble, France
	Stretched-wire (SW) measurements of magnetic multipoles have been performed at radii ranging from 0.5 mm to 4 mm, with an accuracy of 10^-3 of the main multipole component. Theoretical aspects of SW measurements were investigated. The processing of the measured signals is based on a least square approach, instead of the Fourier transform widely used for rotating coil measurements. It allows correcting numerically the position errors of the SW and designing SW trajectory which are not sensitive to the main multipole, as with “bucked” rotating coils. This SW measurement bench was developed for the characterization of new ESRF magnets. It has been tested first with large aperture multipole magnets. An accuracy of 10^-4 has been obtained for a measurement radius of 30 mm. There is a demand in the magnetic measurement community for measuring small bore multipole magnets, with radius smaller than 5 mm. A small permanent magnet quadrupole was built in order to test the bench at small measurement radii.

THPPD007	ILSF Storage Ring Magnets	quadrupole, sextupole, dipole, power-supply	3506
	S. Fatehi, R. Aslani, M.R. Khabbazi IPM, Tehran, Iran
	Iranian Light Source Facility (ILSF) is a 3 GeV storage ring consisting 32 combined bending magnets in 2 types, 10⁴ quadrupoles in 9 families and 128 sextupoles in 9 families. It was decided to use curved C-type, parallel ends, combined bending magnets that have the same lengths, a central fields of 1.42 T and total gap of 32 mm but quadrupole components of g1=-3.837 and g2=-5.839 T/m. Using two dimensional code POISSON and FEMM and applying appropriate shims, pole profile was optimized to maintain the field homogeneity over the full horizontal aperture of ±10, such that, field tolerance is of the order of 10^-4. Also a pole and yoke geometry was developed for the quadrupole, with a field gradient of 23 T/m, bore radius of 30.5 mm and magnetic length of 0.53m which is the maximum possible values in the lattice. Obtained field tolerance is of the order of 10^-4 in the good field region 18 mm. Sextupoles are supposed to have a bore radius of 34 mm, max sextupole component of 700 T/m2 and are designed in order to achieve a field tolerance of 10^-3 in the good field region of 12 mm. Also in order to investigate the end effects 3D calculations has been done by using Radia 3D code.

THPPD010	Design, Assembly and First Measurements of a Short Model for CLIC Final Focus Hybrid Quadrupole QD0	quadrupole, magnet-design, lattice, permanent-magnet	3515
	M. Modena, O. Dunkel, J.G. Perez, C. Petrone, P.A. Thonet, D. Tommasini CERN, Geneva, Switzerland E. Solodko, A.S. Vorozhtsov JINR, Dubna, Moscow Region, Russia
	In the framework of the Compact Linear Collider (CLIC) R&D, a tunable hybrid magnet design has been proposed for the final focus QD0 quadrupole. A short model of the magnet has been realized in order to validate the novel design and its expected performances. In order to achieve extremely high quadrupole gradients (>500 T/m), the magnet design combines: a core structure made in magnetic CoFe alloy “Permendur”, permanent magnet blocks, and air-cooled electromagnetic coils. Relevant aspects of this design are the wide tunability of the gradient range, the compactness and the absence of any vibrations. In this paper a reminder of the magnet design concept is given; then, the procurement and assembly main aspects are presented, followed by the results of the magnetic measurements. Finally, some manufacturing considerations relative to a full size magnet procurement are discussed.

THPPD015	Character and Performance of Magnets for the TPS Storage Ring	sextupole, quadrupole, dipole, storage-ring	3527
	J.C. Jan, C.-H. Chang, H.-H. Chen, Y.L. Chu, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, C.S. Yang, Y.T. Yu NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is a third-generation light source. The orbit of the electron beam will be controlled with 48 dipoles, 240 quadrupoles, 168 sextupoles and several correctors in the storage ring. The construction of the first magnets for one sector, including prototype magnets, is to be completed during 2011 December. The mechanical dimensions of these magnets have been examined on a precise 3D-coordinate-measuring machine (CMM). The field strength, effective length and multipole errors were inspected with a rotating-coil measurement system (RCS) and a Hall-probe measurement system (HPS). The field center of the quadrupole and sextupole magnets is shimmed with a precise shimming block on the RCS bench. The inaccuracy of the position of the field center will be within 0.01 mm after shimming the feet. This work reports the current status, the construction performance, the mechanical shimming algorithm and the relative construction issue of the high precision magnet.

THPPD016	Construction and Measurement of Novel Adjustable Permanent Magnet Quadrupoles for CLIC	quadrupole, permanent-magnet, collider, linear-collider	3530
	B.J.A. Shepherd, J.A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom N.A. Collomb STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	The CLIC drive beam decelerator requires 41,848 quadrupoles along its 42km length. In response to concerns over the heat load and operating costs of electromagnet systems, ASTeC in collaboration with CERN is developing adjustable permanent magnet-based quadrupoles. This novel design concept uses moving permanent magnets to adjust the quadrupole strength over a wide operating range. The design has focused not just on achieving the field strength and quality required but has also tried to make the design well suited to mass production, as the CLIC project requires 50 magnets to be completed every day for three years. Two permanent magnet quadrupole families have been designed, for the low and high energy ends of the decelerator respectively. We present the current status of the project, including construction and magnetic measurements of the first prototype.

THPPD021	SC Magnet Development for SIS100 at FAIR	quadrupole, dipole, sextupole, cryogenics	3545
	E.S. Fischer, A. Mierau, P. Schnizer GSI, Darmstadt, Germany
	Superconducting magnets have been constructed and tested for the SIS100 (Heavy Ion Synchrotron with a beam rigidity of 100 Tm) of the FAIR project. The requested high quality of the magnetic field as well as the fast periodic ramp of the SIS100 (2T, 1Hz) requires that any source of AC losses is tightly reduced by carefully optimising the 3D geometry of the yoke, choosing the appropriate iron material and minimising the eddy current loops. In addition optimal wire, cable and coil designs have been developed. The residual heat production will be reliable removed by an efficient cooling scheme. The beam pipe vacuum chamber must operate stably as a cryo-pump with surface temperatures below 20K. The electromagnetic, thermal and mechanical aspects were optimised and finally investigated based on physical analysis, supported by FEM calculations and dedicated tests. The results obtained on the main magnets were used for dedicated development of the corrector magnets and their effective integration in the complete cryo-magnet complex of the accelerator. We describe the features of the final magnets next to their optimised fields and present the construction status of the SIS100 magnets.

THPPD030	Characterization of a Measurement System for Dynamic Effects in Large-aperture SC Quadrupole Magnets	quadrupole, superconducting-magnet, insertion, controls	3569
	S. Russenschuck, M. Bajko, M.C.L. Buzio, G. Deferne, O. Dunkel, L. Fiscarelli, D. Giloteaux, L. Walckiers CERN, Geneva, Switzerland
	A new measurement system, based on a large-diameter search-coil rotating in the superfluid helium, a fast digital integrator, a motor drive unit with sliprings, and a flexible software environment was devolped at CERN for the measurement of dynamic effects in superconducting magnets. This system has made it possible the measure, with a resolution of up to 8 Hz, the multipole field errors due to superconductor magnetization and interstrand coupling currents. In the paper we will present the development and calibration of the measurement system, its installation in the vertical cryostat of CERN's recently refurbished test station, and its application to the US-LARP* built, 120-mm-aperture Nb3Sn quadrupole magnet (HQ) for the upgrade of the LHC insertion regions. * P. Arpaia et al. Active Comp. of Field Errors within ± 2 PPM in SC Magnets, NIM A, 2011 ** H. Felice et al. Design of HQ, a High Field Large Bore Nb3Sn Quad. Magnet for LARP, IEEE TAS, 2009

THPPD038	Measurements of the Persistent Current Decay and Snapback Effect in Nb3Sn Accelerator Prototype Magnets at Fermilab	dipole, quadrupole, injection, sextupole	3593
	G. Velev, G. Chlachidze, J. DiMarco, V. Kashikhin Fermilab, Batavia, USA
	In recent years, Fermilab has been performing an intensive R&D program on Nb3Sn accelerator magnets. This program has included dipole and quadrupole magnets for different programs and projects, including LARP and VLHC. A systematic study of the persistent current decay and snapback effect in the fields of these magnets was executed at the Fermilab Magnet Test Facility. The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and flattop and injection plateau durations. This study has mostly focused on the dynamic behavior of the normal sextupole and dodecapole components in dipole and quadrupole magnets respectively. The paper summarizes the recent measurements and presents a comparison with previously measured NbTi magnets.

THPPD043	Radiation-tolerant Multipole Correction Coils for FRIB	quadrupole, octupole, radiation, sextupole	3608
	S.A. Kahn Muons, Inc, Batavia, USA R.C. Gupta BNL, Upton, Long Island, New York, USA
	Multipole correction insert coils with significant field strength are required inside the large aperture superconducting quadrupole magnets in the fragment separator section of the Facility for Rare Isotope Beams (FRIB). Correction coils made with copper do not create the required field and conventional low temperature superconductors are not practical in the fragment separator magnets which will operate at 40-50 K. The correction coils should be made of HTS as the main quadrupole coils are. There is a significant advantage to using HTS in these coils as it can withstand the high radiation and heat load that will be present. This paper will describe an innovative design suitable for coils with the complex end geometry of cylindrical coils. We will look at the forces on the corrector coils from the mail quadrupole fields and anticipate possible coil distortions.

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MOPPC020

Field Tolerances for the Triplet Quadrupoles of the LHC High Luminosity Lattice

quadrupole, dynamic-aperture, target, lattice

169

Y. Jiao, Y. Cai, Y. Nosochkov, M.-H. Wang
SLAC, Menlo Park, California, USA
R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh
CERN, Geneva, Switzerland

Funding: This work is supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
It has been proposed to implement an Achromatic Telescopic Squeezing (ATS) scheme* in the high luminosity LHC lattice to reduce the beta functions at the Interaction Points (IP) up to a factor of 8. As a consequence, the nominal 4.5-km peak beta functions reached in the inner triplets at collision will be increased by the same factor. This therefore justifies the installation of new, larger aperture superconducting triplet quadrupoles. These higher beta functions will enhance the effects of the triplet quadrupole field errors leading to smaller beam dynamic aperture. To maintain the acceptable dynamic aperture, the effects of the triplet multipole field errors must be re-evaluated, thus specifying new tolerances. Such a study has been performed for the so-called “4444” collision optics of the ATS scheme, where the IP beta functions are reduced by a factor of 4 in both planes with respect to a pre-squeezed value of 60 cm at two collision points. The dynamic aperture calculations were performed using SixTrack. The impact on the triplets’ field quality is studied and presented in details.
* S. Fartoukh, “An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade”, Proc. of IPAC11, p. 2088 (2011).

MOPPC024

Modelling of the AGS Using Zgoubi - Status

simulation, optics, closed-orbit, coupling

181

F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, V. Schoefer, N. Tsoupas
BNL, Upton, Long Island, New York, USA

A computer model, based on the ray-tracing code Zgoubi, is being developed in view of on-line simulation of the RHIC injector AGS, and of beam and spin dynamics simulations and studies in the presence of the cold and warm helical partial snakes. A status of this work is given here.

MOPPC053

Modeling of Bending Magnets for SIRIUS

dipole, simulation, lattice, sextupole

250

X.R. Resende, R. Basílio, L. Liu, P.P. Sanchez, G. Tosin
LNLS, Campinas, Brazil

The new Brazilian synchrotron source, Sirius, will be a 3 GeV storage ring with a triple bend lattice with a minimum emittance of 1.7 nm rad. The ring dipoles are excited with permanent magnets. The middle bend has a small 1.4 degree slice in its center with 1.94 T field and serve as an additional hard X-ray source with critical energy of 11.6 keV. Other bending magnets have low 0.50 T field with gradients, allowing for a further emittance reduction. The bending slice shows a longitudinal profile with no uniform field plateau and with long-range fringe fields which are coupled with the fields of neighbouring dipoles. To take into account the interaction of the field-intersecting dipoles, realistic 3D models of the magnets have been created and their field configuration solved using finite element techniques. Field maps calculated from the 3D magnet models were used for the construction of segmented models of bend elements in beam dynamics codes.

MOPPC057

Some Comments to Magnetic Field Representation for Beam Dynamic Calculations

dipole, quadrupole, vacuum, resonance

262

P. Schnizer, E.S. Fischer
GSI, Darmstadt, Germany
A. Mierau
TEMF, TU Darmstadt, Darmstadt, Germany
B. Schnizer
TUG/ITP, Graz, Austria

Machines with high currents and small apertures, as used for SIS100 of the FAIR project, require a sincere understanding of the resonances excited by the magnetic field distortions; typically performed by tracking codes. These codes model the field errors using a Taylor Series approximation of the field quality at the track of the ideal particle. The path of the particle within the elliptic aperture of the dipole is curved; thus the standard approach of using plane circular multipoles fails to model the real symmetry of the magnetic field, an important feature of effective field description for beam loss calculations. Therefore toroidal elliptic multipoles were developed which allow describing the magnetic field concisely in an elliptic vacuum chamber in curved dipoles and quadrupoles. In this talk we present the appropriate description and its limitation, illustrate their usefullness based on the static and transient magnetic field measurements of the first curved SIS100 dipole next to the SIS18 dipole.

MOPPC073

Improvements in the PLACET Tracking Code

simulation, ground-motion, linac, alignment

301

A. Latina, E. Adli, D. Schulte, J. Snuverink
CERN, Geneva, Switzerland
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. It has an interface based on both Tcl/Tk and Octave to provide maximum flexibility and easy programming of complex scenarios. Recently, new functionality has been added to expand its simulation and tuning capabilities, such as: tools to perform beam-based alignment of non-linear optical systems, possibility to track through the interaction region in presence of external magnetic fields (detector solenoid), higher order imperfections in magnets, better tools for integrated feedback loops. Moreover, self contained frameworks have been created to ease the simulation of CLIC Drive Beam, CLIC Main Beam, and other existing electron machines such as CTF3 and FACET.

MOPPC074

Evolution of MAD-X in the Framework of LHC Upgrade Studies

simulation, optics, luminosity, quadrupole

304

A. Latina, L. Deniau
CERN, Geneva, Switzerland

The design efforts for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will require significant extensions of the MAD-X code widely used for designing and simulating particles accelerators. For this purpose, several new capabilities have been added to the code, namely the possibility to simulate crab cavities for crossing angle compensation, with their imperfections; the selective introduction of thick quadrupole elements for particles tracking, improving the previous implementation entirely based on thin-lenses; and the upgrade of the interface to SixTrack used for distributed tracking with, e.g., LHC@home. These changes are framed into a global redesign of the MAD-X architecture meant to consolidate its structure, improve its performances, and increase its flexibility. Such improvements are described in details in the present paper.

MOPPC077

Simulation and Analysis of the Beam Signal in Taiwan Photon Source Booster

booster, lattice, betatron, synchrotron

313

C.C. Chiang, H.-P. Chang, P.J. Chou
NSRRC, Hsinchu, Taiwan
S.-Y. Lee
IUCEEM, Bloomington, Indiana, USA

The TPS (Taiwan Photon Source) booster is a combined function FODO lattice with six super-periods; the total circumference is 496.8 m. To prepare the analysis tools for beam commissioning, we simulate the TPS booster turn-by-turn BPM data with two programs, MAD-X PTC and Tracy-2.6, which are for both DC (constant beam energy) and AC (beam energy in regular ramping) modes. We analyze the simulation data with MIA (Model Independent Analysis) and ICA (Independent Component Analysis), in order to reconstruct beam parameters like beta function, phase advance, dispersion, etc. We include multipole errors, alignment errors, BPM noises or other noises in simulation, and try to design a good strategy for real data analysis.

MOPPC093

Optimal Fast Multipole Method Data Structures

target, electron, simulation, space-charge

352

S. Abeyratne, B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA
S.L. Manikonda
ANL, Argonne, USA

The Fast Multipole Method (FMM) has been identified as one of the ten most significant numerical algorithms discovered in the 20th century. The FMM guarantees finding fast solutions to many problems in science, such as calculating Coulomb potentials among large number of particles by reducing memory footprint and run time while attaining very high accuracy levels. One important practical issue that we have to solve in implementing a FMM algorithm is organizing large amounts of data, also called data structuring. The non-adaptive FMM is appropriate when the particles are uniformly distributed while the adaptive FMM is most efficient when the distribution is non-uniform. In practice, we typically encounter highly non-uniform 3D particle distributions. This paper summarizes our implementation of a 3D adaptive FMM algorithm data structure setup for non-uniform particle distributions.

MOPPP079

Magnetic Tuning of the APS Wiggler as a Study for Tuning the NSLS-II Damping Wiggler

wiggler, damping, octupole, insertion

747

I. Vasserman, M. Abliz, E. Gluskin, E. Trakhtenberg, J.Z. Xu
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
A wide variety of tuning techniques has been developed and employed at Advanced Photon Source (APS) in the course of tuning insertion devices for use on the APS storage ring, the APS free electron laser, and in assisting with the LCLS undulator tuning. The tuning requirements for the National Synchrotron Source II (NSLS-II) damping wigglers are very demanding and include limits on the off-midplane field integrals that are new in the repertoire of undulator magnetic tuning. The goal of this study was to assess the applicability of existing tuning techniques to meeting the off-midplane requirements of NSLS-II. Tests were run using an available APS 8.5-cm-period wiggler. In addition to existing techniques, a special new shim design was tested. This report summarizes the results of these tests and shows that the wiggler can be tuned to the required specifications on the midplane over the requested ±15 mm in the horizontal direction. In the vertical direction, however, the specifications could only be met within ±0.5 mm. This falls short of the ±15 mm by ± 3 mm good-field region that is sought by NSLS-II.

TUOAA02

Focusing Charged Particle Beams Using Multipole Magnets in a Beam Transport Line

sextupole, octupole, target, focusing

1062

Y. Yuri, I. Ishibori, T. Ishizaka, S. Okumura, T. Yuyama
JAEA/TARRI, Gunma-ken, Japan

The intensity distribution of a charged-particle beam is transformed by applying the nonlinear focusing force of a multipole magnet. In this paper, the transformation of the transverse intensity distribution due to the second-order sextupole and third-order octupole focusing force in the beam transport line is explored. As a measure of the distribution transformation induced by the multipole magnets, the beam centroid displacement and the change of the beam size have been analytically derived using the distribution function of the beam. It is numerically verified how the transverse distribution of the beam is transformed by the multipole magnets. As an application of the distribution transformation by nonlinear focusing, a uniform beam can be formed from a Gaussian beam using multipole magnets. The current status and future plan of the experiment on the uniform-beam formation at the cyclotron facility in Japan Atomic Energy Agency will be shown.

Slides TUOAA02 [2.032 MB]

TUPPC001

Quadrupole Shapes

quadrupole, optics, TRIUMF, controls

1149

R.A. Baartman
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Traditionally, quadrupoles are shaped to have a constant vertical cross-section. In other words, the poles are cylindrical segments extended in the beam direction and circular or hyperbolic in cross section. At the ends, the poles are simply truncated or sometimes slightly smoothed with a chamfer. Even very short quadrupoles are often this shape. A new shape is derived analytically, and it is demonstrated that this shape yields dramatically smaller aberrations.

TUPPC009

Dihedral Group and Repetitive Achromats with Mirror Symmetric or Mirror Antisymmetric Basic Cell

electron, resonance, focusing, free-electron-laser

1170

V. Balandin, R. Brinkmann, W. Decking, N. Golubeva
DESY, Hamburg, Germany

Using the group-theoretical point of view for the design of magnetic optical achromats as introduced in*, we study in this paper second- and third-order repetitive achromats with a mirror symmetric or mirror antisymmetric basic cell. We also compare these achromats with repetitive achromats designed without internal cell symmetries taken into account.
* V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Two Cell Repetitive Achromats and Four Cell Mirror Symmetric Achromats, Proceedings of IPAC'10, Kyoto, Japan.

TUPPC042

Effect of Field Errors in Muon Collider IR Magnets on Beam Dynamics

dipole, sextupole, quadrupole, dynamic-aperture

1257

Y. Alexahin, E. Gianfelice-Wendt, V.V. Kapin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
In order to achieve peak luminosity of a Muon Collider (MC) in the 10³⁵/cm²/s range very small values of beta-function at the interaction point (IP) are necessary (β^* ~ 5 mm) while the distance from IP to the first quadrupole can not be made shorter than ~6m as dictated by the necessity of detector protection from backgrounds. In the result the beta-function at the final focus quadrupoles can reach 100 km making beam dynamics very sensitive to all kind of errors. In the present report we consider the effects on momentum acceptance and dynamic aperture of multipole field errors in the body of IR dipoles as well as of fringe-fields in both dipoles and quadrupoles in the case of 1.5 TeV (c.o.m.) MC. Analysis shows these effects to be strong but correctable with dedicated multipole correctors.

TUPPC050

Beam Transport and Storage with Cold Neutral Atoms and Molecules

sextupole, solenoid, injection, quadrupole

1281

P.L. Walstrom, M.D. Di Rosa
LANL, Los Alamos, New Mexico, USA

Funding: US Department of Energy
Paramagnetic neutral atoms and molecules are subject to magnetic-field-gradient forces on their magnetic moments. Li atoms and CaH molecules both have an effective magnetic moment of about one Bohr magneton, and in the presence of a strong (~1 T) magnetic field, acquire a Zeeman energy of one of two values, ±μ|B|. Particles with positive (negative) energy are repelled by (attracted toward) increasing fields. Li and CaH can be laser-cooled to speeds of tens of m/s and the corresponding magnetic fields needed for transport and injection are on the order of 1 T. The stable stored state is the field-repelled state. Many concepts of accelerator physics apply to our neutral particles. The analog of charge-exchange injection into storage rings is laser-based optical pumping from a field-seeking state to a field-repelled state. The role of dipoles in charged-particle optics is played by quadrupoles in neutral particle optics, and the role of quadrupoles by sextupoles. We present our design and tracking results for a neutral atom/molecule accumulator including an injection chicane with a laser-stimulated state-flip.

TUPPP001

Beam Based Measurements with Superconducting Wigglers at the Canadian Light Source with Applications to Nonlinear Beam Dynamics

wiggler, injection, dynamic-aperture, optics

1599

W.A. Wurtz, L.O. Dallin, M.J. Sigrist
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source (CLS) employs two superconducting wigglers for the production of hard x-rays. These wigglers cause a large decrease in injection efficiency. While such a decrease is not unexpected due to the large distortion to the linear optics, a correction to the linear optics does not restore injection efficiency. This inability to restore injection is not predicted by a kickmap model of the wiggler. We performed beam based measurements to construct a phenomenological, nonlinear model of the wiggler. Particle tracking with this wiggler model shows that the reduction in dynamic aperture is due to the amplitude dependent tune shift crossing a resonance, even with the linear optics corrected. Moving the tunes allows us to avoid this resonance and measurements at these tunes show that injection efficiency is not greatly affected by the wigglers.

TUPPP011

Simulations of Fringe Fields and Multipoles for the ANKA Storage Ring Bending Magnets

simulation, optics, sextupole, storage-ring

1626

M. Streichert, M.J. Nasse
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
V. Afonso Rodriguez, A. Bernhard, N. Hiller, E. Huttel, V. Judin, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M. Schwarz, N.J. Smale
KIT, Karlsruhe, Germany

Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320.
ANKA is the synchrotron light source of the Karlsruhe Institute of Technology (KIT). With a maximum particle energy of 2.5 GeV, the storage ring lattice consists of 16 bending magnets with a nominal magnetic flux density of 1.5 T. For the beam dynamics simulations the consideration of the fringe fields and multipoles is essential. A reference measurement of the longitudinal magnetic flux density profile of a bending magnet exists for a current of 650 A, corresponding to a particle energy of 2.46 GeV. For lower beam energies where the magnets are no longer close to saturation, however, the exact density profiles may vary significantly. In order to derive fringe fields and multipole components for different beam energies, simulations of the magnetic flux density for different beam energies were conducted using a finite element method (FEM). We present the results of the simulations and demonstrate the improvements of the beam dynamics simulations in AT (Accelerator Toolbox).

TUPPP013

Effects of Multipoles in Dynamic Aperture of the ILSF Storage Ring

dynamic-aperture, sextupole, quadrupole, lattice

1632

S. Fatehi, E. Ahmadi, F. Saeidi
ILSF, Tehran, Iran
D. Einfeld
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
H. Ghasem
IPM, Tehran, Iran

Dynamic aperture of a synchrotron light source shrinks to small value due to the multipole errors caused by magnet design. In the ILSF storage ring, the tolerance of magnets has been taken into account in the simulation and sextupole magnets reoptimized to improve the dynamic aperture. This paper yields the evaluated dynamic aperture include of multipole errors.

TUPPR027

Study of Multipolar RF Kicks from the Main Deflecting Mode in Compact Crab Cavities for LHC

cavity, dipole, simulation, coupling

1873

A. Grudiev, J. Barranco, R. Calaga, R. De Maria, M. Giovannozzi, R. Tomás
CERN, Geneva, Switzerland

A crab cavity system is under design in the frame work of the High Luminosity LHC project. Due to transverse space constraints on one hand and the RF frequency requirements on the other hand, the design of the crab cavities has to be compact. This results in the crab cavity shape being far from axially symmetric and, as a consequence, higher order multipolar components of the main deflecting mode are non-zero. In this paper, multipolar RF kicks from the main deflecting mode have been calculated in the compact crab cavities for LHC. They are compared to the multipolar error in magnetic elements of LHC. The influence of the RF kicks on the beam dynamics has been investigated and possible acceptable tolerances are presented.

TUPPR066

Characterization of Single Particle Dynamics for the International Linear Collider Damping Ring Lattice

damping, emittance, wiggler, lattice

1972

J.P. Shanks, J.A. Crittenden, M.A. Palmer
CLASSE, Ithaca, New York, USA
D.L. Rubin
Cornell University, Ithaca, New York, USA

Funding: DOE Award DE-SC0006506
The baseline design for the International Linear Collider damping rings is a 3.2 km circumference racetrack, with 5 GeV beam energy. The transverse damping time is 26 ms and the normalized horizontal emittance 5 mm-mrad. Nearly 60 2.2-m-long superconducting wigglers per ring increase the radiation damping rate by an order of magnitude and reduce horizontal emittance by a factor of 5. We characterize the sensitivity to magnet misalignments and field errors, and establish the minimum numbers of corrector magnets and beam position monitors required for tuning vertical emittance to less than 20 nm-rad. We validate the specified tolerable guide field multipole errors consistent with adequate dynamic aperture. Tune scans are used to identify stable working points. In tracking studies we use a wiggler model based on fits to 3-dimensional field maps.

WEEPPB013

Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR

dipole, quadrupole, octupole, background

2191

B. Parker, M. Anerella, J. Escallier, A.K. Ghosh, A.K. Jain, A. Marone, P. Wanderer
BNL, Upton, Long Island, New York, USA
Y. Arimoto, M. Iwasaki, N. Ohuchi, M. Tawada, K. Tsuchiya, H. Yamaoka, Z.G. Zong
KEK, Ibaraki, Japan

Upgrade of the KEKB asymmetric e⁺e⁻ collider for a forty-fold luminosity increase, denoted SuperKEKB, is now underway. For SuperKEKB the beam crossing angle is increased to provide separate focusing channels for the incoming and outgoing electron and positrons beams in new superconducting Interaction Region (IR) magnets. Two functional classes of superconducting corrector magnets are needed to meet SuperKEKB beam optics goals. Dipole, skew-dipole, skew-quadrupole and octupole coil windings will be inserted inside the bores of the main IR quadrupoles to make magnet center alignments, roll adjustments and non-linear optics corrections. A second class of high-order magnetic multipole corrector coils is needed to compensate the non-linear fringe field experienced by the circulating beam that passes just outside the main quadrupole coils that are closest to the Interaction Point (IP). Near the IP there is no space for magnetic yokes or other passive shielding to diminish the fringe field. At the time of this conference the SuperKEKB corrector magnet production will be under way. The SuperKEKB correction coil design and our production technique are reviewed in this paper.

WEPPC044

Multipole Effects Study for Project X Front End Cavities

cavity, quadrupole, linac, focusing

2309

P. Berrutti, M.H. Awida, I.V. Gonin, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Effects of RF field asymmetry along with multipoles have been studied in Project X front end cavities. One family of half wave resonators operating at 162.5 and two of spoke resonators operating at 325 MHz have been analysed. HWR and spoke resonators unlike elliptical cavities, do not have axial symmetry, hence a quadrupole perturbation to the beam is present. The purpose of this paper is to explain the approach and the calculation method used to understand and overcome the drawbacks due to the RF field asymmetry.

WEPPC047

Effects of the RF Field Asymmetry in SC Cavities of the Project X

linac, cavity, acceleration, focusing

2318

I.V. Gonin, M.H. Awida, P. Berrutti, A. Saini, B.G. Shteynas, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA
P.N. Ostroumov
ANL, Argonne, USA

The low-energy SCRF section of CW SC linac of Project X starts from Half Wave Resonators (HWR) having operating frequency f=162.5 MHz, optimal β= 0.11 and will accelerate the beam from 2 MeV up to 11 MeV. The preliminary analysis of beam dynamics shows that multipole effects caused by asymmetry of RF fields in HWR cavities aren’t negligible. In this paper we present the analysis of influence of multipole effects on beam dynamics and discuss the possible solutions how to compensate these effects.

WEPPC103

Development of Spoke Cavities for High-velocity Applications

electron, cavity, higher-order-mode, impedance

2456

C.S. Hopper, J.R. Delayen
ODU, Norfolk, Virginia, USA
R.G. Olave
Old Dominion University, Norfolk, Virginia, USA

In response to recent interest in alternatives to elliptical cavities for low-frequency, high-velocity applications we have initiated a program for the development of multi-spoke superconducting cavities. We have completed the electromagnetic design for two-spoke cavities operating at 352 and 325 MHz and a design velocity of β = 0.82 and β = 1. We present the results of the optimization, higher order mode (HOM) analysis, multipacting analysis, and an initial multipole expansion study of the fundamental accelerating mode.

WEPPD026

Design and Fabrication of NSLS-II Storage Ring Vacuum Chambers and Components

vacuum, storage-ring, photon, impedance

2558

H.-C. Hseuh, A.T. Anderson, L. Doom, M.J. Ferreira, C. Hetzel, C. Longo, V. Ravindranath, K. Roy, S.K. Sharma, J.L. Tuozzolo, K. Wilson
BNL, Upton, Long Island, New York, USA

Funding: Work performed under the auspices of U.S. Department of Energy, under contract DE-AC02-98CH10886
The National Synchrotron Light Source II, a 3-GeV, 792-meter circumference, synchrotron radiation facility with ultra-high-flux and brightness, is under construction at Brookhaven National Laboratory. The storage ring vacuum chambers are mainly made of extruded aluminium but with a few made of stainless steel and inconel. The synchrotron radiation from bending magnets is intercepted at discrete photon absorbers made of GlidCop. NEG strips in the ante-chamber provide the distributed pumping, while lumped ion pumps and titanium sublimation pumps at photon absorbers remove the desorbed gas. The complex vacuum system is being assembled and integrated in-house. This paper describes the design and fabrication of both standard and special vacuum chambers, the low impedance RF shielded bellows and the photon absorbers. The vacuum system is now moving into the conditioning, installation and testing phase. Details and experience from the large scale production, testing and lesson learned will also be presented.

WEPPR067

Study of Fundamental Mode Multipolar Kicks in Double- and Single-feed Power Couplers for the CLIC Main Linac Accelerating Structure

linac, simulation, emittance, cavity

3081

A. Latina, A. Grudiev, D. Schulte
CERN, Geneva, Switzerland

Multipolar kicks from the fundamental mode have been calculated in the CLIC baseline accelerating structure with double–feed input and output power couplers. The influence of such multipolar kicks on the main linac beam dynamics has been investigated. Furthermore, an alternative design of the couplers with single-feed has been studied and compared with the double-feed. Such an alternative would significantly simplify the waveguide system of the main linac but potentially introduce an harmful dipolar kick from the fundamental mode. The geometry of the coupler has been optimized in order to minimize such a dipolar kick and keep it below threshold levels determined with beam dynamics simulations. Influence of the higher order multipoles has been investigated as well and acceptable levels have been determined.

THPPD001

Stretched-wire Measurements of Small Bore Multipole Magnets

quadrupole, permanent-magnet, simulation, alignment

3500

G. Lebec, J. Chavanne, C. Penel
ESRF, Grenoble, France

Stretched-wire (SW) measurements of magnetic multipoles have been performed at radii ranging from 0.5 mm to 4 mm, with an accuracy of 10^-3 of the main multipole component. Theoretical aspects of SW measurements were investigated. The processing of the measured signals is based on a least square approach, instead of the Fourier transform widely used for rotating coil measurements. It allows correcting numerically the position errors of the SW and designing SW trajectory which are not sensitive to the main multipole, as with “bucked” rotating coils. This SW measurement bench was developed for the characterization of new ESRF magnets. It has been tested first with large aperture multipole magnets. An accuracy of 10^-4 has been obtained for a measurement radius of 30 mm. There is a demand in the magnetic measurement community for measuring small bore multipole magnets, with radius smaller than 5 mm. A small permanent magnet quadrupole was built in order to test the bench at small measurement radii.

THPPD007

ILSF Storage Ring Magnets

quadrupole, sextupole, dipole, power-supply

3506

S. Fatehi, R. Aslani, M.R. Khabbazi
IPM, Tehran, Iran

Iranian Light Source Facility (ILSF) is a 3 GeV storage ring consisting 32 combined bending magnets in 2 types, 10⁴ quadrupoles in 9 families and 128 sextupoles in 9 families. It was decided to use curved C-type, parallel ends, combined bending magnets that have the same lengths, a central fields of 1.42 T and total gap of 32 mm but quadrupole components of g1=-3.837 and g2=-5.839 T/m. Using two dimensional code POISSON and FEMM and applying appropriate shims, pole profile was optimized to maintain the field homogeneity over the full horizontal aperture of ±10, such that, field tolerance is of the order of 10^-4. Also a pole and yoke geometry was developed for the quadrupole, with a field gradient of 23 T/m, bore radius of 30.5 mm and magnetic length of 0.53m which is the maximum possible values in the lattice. Obtained field tolerance is of the order of 10^-4 in the good field region 18 mm. Sextupoles are supposed to have a bore radius of 34 mm, max sextupole component of 700 T/m2 and are designed in order to achieve a field tolerance of 10^-3 in the good field region of 12 mm. Also in order to investigate the end effects 3D calculations has been done by using Radia 3D code.

THPPD010

Design, Assembly and First Measurements of a Short Model for CLIC Final Focus Hybrid Quadrupole QD0

quadrupole, magnet-design, lattice, permanent-magnet

3515

M. Modena, O. Dunkel, J.G. Perez, C. Petrone, P.A. Thonet, D. Tommasini
CERN, Geneva, Switzerland
E. Solodko, A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

In the framework of the Compact Linear Collider (CLIC) R&D, a tunable hybrid magnet design has been proposed for the final focus QD0 quadrupole. A short model of the magnet has been realized in order to validate the novel design and its expected performances. In order to achieve extremely high quadrupole gradients (>500 T/m), the magnet design combines: a core structure made in magnetic CoFe alloy “Permendur”, permanent magnet blocks, and air-cooled electromagnetic coils. Relevant aspects of this design are the wide tunability of the gradient range, the compactness and the absence of any vibrations. In this paper a reminder of the magnet design concept is given; then, the procurement and assembly main aspects are presented, followed by the results of the magnetic measurements. Finally, some manufacturing considerations relative to a full size magnet procurement are discussed.

THPPD015

Character and Performance of Magnets for the TPS Storage Ring

sextupole, quadrupole, dipole, storage-ring

3527

J.C. Jan, C.-H. Chang, H.-H. Chen, Y.L. Chu, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, C.S. Yang, Y.T. Yu
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is a third-generation light source. The orbit of the electron beam will be controlled with 48 dipoles, 240 quadrupoles, 168 sextupoles and several correctors in the storage ring. The construction of the first magnets for one sector, including prototype magnets, is to be completed during 2011 December. The mechanical dimensions of these magnets have been examined on a precise 3D-coordinate-measuring machine (CMM). The field strength, effective length and multipole errors were inspected with a rotating-coil measurement system (RCS) and a Hall-probe measurement system (HPS). The field center of the quadrupole and sextupole magnets is shimmed with a precise shimming block on the RCS bench. The inaccuracy of the position of the field center will be within 0.01 mm after shimming the feet. This work reports the current status, the construction performance, the mechanical shimming algorithm and the relative construction issue of the high precision magnet.

THPPD016

Construction and Measurement of Novel Adjustable Permanent Magnet Quadrupoles for CLIC

quadrupole, permanent-magnet, collider, linear-collider

3530

B.J.A. Shepherd, J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The CLIC drive beam decelerator requires 41,848 quadrupoles along its 42km length. In response to concerns over the heat load and operating costs of electromagnet systems, ASTeC in collaboration with CERN is developing adjustable permanent magnet-based quadrupoles. This novel design concept uses moving permanent magnets to adjust the quadrupole strength over a wide operating range. The design has focused not just on achieving the field strength and quality required but has also tried to make the design well suited to mass production, as the CLIC project requires 50 magnets to be completed every day for three years. Two permanent magnet quadrupole families have been designed, for the low and high energy ends of the decelerator respectively. We present the current status of the project, including construction and magnetic measurements of the first prototype.

THPPD021

SC Magnet Development for SIS100 at FAIR

quadrupole, dipole, sextupole, cryogenics

3545

E.S. Fischer, A. Mierau, P. Schnizer
GSI, Darmstadt, Germany

Superconducting magnets have been constructed and tested for the SIS100 (Heavy Ion Synchrotron with a beam rigidity of 100 Tm) of the FAIR project. The requested high quality of the magnetic field as well as the fast periodic ramp of the SIS100 (2T, 1Hz) requires that any source of AC losses is tightly reduced by carefully optimising the 3D geometry of the yoke, choosing the appropriate iron material and minimising the eddy current loops. In addition optimal wire, cable and coil designs have been developed. The residual heat production will be reliable removed by an efficient cooling scheme. The beam pipe vacuum chamber must operate stably as a cryo-pump with surface temperatures below 20K. The electromagnetic, thermal and mechanical aspects were optimised and finally investigated based on physical analysis, supported by FEM calculations and dedicated tests. The results obtained on the main magnets were used for dedicated development of the corrector magnets and their effective integration in the complete cryo-magnet complex of the accelerator. We describe the features of the final magnets next to their optimised fields and present the construction status of the SIS100 magnets.

THPPD030

Characterization of a Measurement System for Dynamic Effects in Large-aperture SC Quadrupole Magnets

quadrupole, superconducting-magnet, insertion, controls

3569

S. Russenschuck, M. Bajko, M.C.L. Buzio, G. Deferne, O. Dunkel, L. Fiscarelli, D. Giloteaux, L. Walckiers
CERN, Geneva, Switzerland

A new measurement system, based on a large-diameter search-coil rotating in the superfluid helium, a fast digital integrator, a motor drive unit with sliprings, and a flexible software environment was devolped at CERN for the measurement of dynamic effects in superconducting magnets*. This system has made it possible the measure, with a resolution of up to 8 Hz, the multipole field errors due to superconductor magnetization and interstrand coupling currents. In the paper we will present the development and calibration of the measurement system, its installation in the vertical cryostat of CERN's recently refurbished test station, and its application to the US-LARP** built, 120-mm-aperture Nb3Sn quadrupole magnet (HQ) for the upgrade of the LHC insertion regions.
* P. Arpaia et al. Active Comp. of Field Errors within ± 2 PPM in SC Magnets, NIM A, 2011
** H. Felice et al. Design of HQ, a High Field Large Bore Nb3Sn Quad. Magnet for LARP, IEEE TAS, 2009

THPPD038

Measurements of the Persistent Current Decay and Snapback Effect in Nb3Sn Accelerator Prototype Magnets at Fermilab

dipole, quadrupole, injection, sextupole

3593

G. Velev, G. Chlachidze, J. DiMarco, V. Kashikhin
Fermilab, Batavia, USA

In recent years, Fermilab has been performing an intensive R&D program on Nb3Sn accelerator magnets. This program has included dipole and quadrupole magnets for different programs and projects, including LARP and VLHC. A systematic study of the persistent current decay and snapback effect in the fields of these magnets was executed at the Fermilab Magnet Test Facility. The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and flattop and injection plateau durations. This study has mostly focused on the dynamic behavior of the normal sextupole and dodecapole components in dipole and quadrupole magnets respectively. The paper summarizes the recent measurements and presents a comparison with previously measured NbTi magnets.

THPPD043

Radiation-tolerant Multipole Correction Coils for FRIB

quadrupole, octupole, radiation, sextupole

3608

S.A. Kahn
Muons, Inc, Batavia, USA
R.C. Gupta
BNL, Upton, Long Island, New York, USA

Multipole correction insert coils with significant field strength are required inside the large aperture superconducting quadrupole magnets in the fragment separator section of the Facility for Rare Isotope Beams (FRIB). Correction coils made with copper do not create the required field and conventional low temperature superconductors are not practical in the fragment separator magnets which will operate at 40-50 K. The correction coils should be made of HTS as the main quadrupole coils are. There is a significant advantage to using HTS in these coils as it can withstand the high radiation and heat load that will be present. This paper will describe an innovative design suitable for coils with the complex end geometry of cylindrical coils. We will look at the forces on the corrector coils from the mail quadrupole fields and anticipate possible coil distortions.