Keyword: sextupole
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MOOAB03 FACET First Beam Commissioning linac, emittance, damping, lattice 46
 
  • G. Yocky, C.I. Clarke, W.S. Colocho, F.-J. Decker, M.J. Hogan, N. Lipkowitz, J. Nelson, P.M. Schuh, J.T. Seeman, J. Sheppard, H. Smith, T.J. Smith, M. Stanek, Y. Sun, J.L. Turner, M.-H. Wang, S.P. Weathersby, G.R. White, U. Wienands, M. Woodley
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515.
The FACET (Facility for Advanced aCcelerator Experimental Tests) facility at SLAC has been under Construction since summer 2010. Its goal is to produce ultrashort and transversely small bunches of very high intensity (20kA peak current) to facilitate advanced acceleration experiments like PWFA and DLA. In June of 2011 the first electron beam was brought into the newly constructed bunch-compression chicane. Commissioning work included restarting the linac and damping ring, verifying hardware, establishing a good beam trajectory, verifying the optics of the chicane, commissioning diagnostic devices for transverse and longitudinal bunch size, and tuning up the beam size and bunch compression. Running a high-intensity beam through the linac without BNS damping and with large energy spread is a significant challenge. Optical aberrations as well as wakefields conspire to increase beam emittance and the bunch compression is quite sensitive to details of the beam energy and orbit, not unlike what will be encountered in a linear-collider final-focusing system. In this paper we outline the steps we took while commissioning as well as the challenges encountered and how they were overcome. 		 
slides icon Slides MOOAB03 [9.167 MB]  
 
MOPPC002 Local Chromatic Correction Scheme and Crab-waist Collisions for an Ultra-low β* at the LHC optics, quadrupole, luminosity, resonance 118
 
  • J.L. Abelleira, S. Russenschuck, R. Tomás, F. Zimmermann
    CERN, Geneva, Switzerland
  • J.L. Abelleira
    EPFL, Lausanne, Switzerland
  • C. Milardi, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • K. Ohmi
    KEK, Ibaraki, Japan
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  
  Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579.
We discuss potential merits and the parameter range of interest for a possible crab-waist collision scheme at the LHC, and report preliminary optics studies of a local chromatic correction scheme with flat beams (βx*>>βy*), which could boost the LHC luminosity by about an order of magnitude and would also allow for crab-waist collisions. 		 
 
MOPPC010 Parametric Study of Optics Options for the HL-LHC Project optics, quadrupole, luminosity, insertion 142
 
  • R. De Maria
    CERN, Geneva, Switzerland
  
  Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, cofunded by the DoE, USA and KEK, Japan.
The LHC Upgrade studies have been recently formalized into the High-Luminosity LHC (HL-LHC) project. The paper explores the parameter space in terms minimum beta star (flat and round), and luminosity leveling scenarios, constrained by the triplet gradient and aperture and still compatible with optics solutions based on the ATS scheme*. The limitations of the proposed solutions, essentially given by the preservation of the dynamic aperture in the presence of large beta-beating waves induced in the arcs by the squeezing scheme are investigated. The results will be combined in scaling laws benchmarked with existing fully developed scenarios.
* S. Fartoukh et al., "The Achromatic Telescopic Squeezing (ATS) scheme: from initial motivations to basic principles, and first demonstration at the LHC," these proceedings. 		 
 
MOPPC029 Off-momentum Beat-beat Correction in the RHIC Proton Run quadrupole, simulation, proton, lattice 196
 
  • Y. Luo, M. Bai, W. Fischer, A. Marusic, K. Mernick, S.M. White
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this article we will present the measurement and correction of the off-momentum β*-beat in the RHIC proton run. The beta-beat will be measured with the AC dipole and by shifting RF frequency. We will focus on the correction of the off-momentum beta-beat at the interaction points IP6 and IP8 with the arc chromatic sextupole families. The effects of the off-momentum beta-beat correction on the global chromaticities and dynamic aperture will be estimated through beam experiments and the numerical simulation. 		 
 
MOPPC053 Modeling of Bending Magnets for SIRIUS dipole, simulation, multipole, lattice 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.  
 
MOPPC076 New Features of the Parallel TRACY for Nonlinear Beam Dynamics lattice, dynamic-aperture, closed-orbit, betatron 310
 
  • M.-S. Chiu, H.-P. Chang
    NSRRC, Hsinchu, Taiwan
  
  The TRACY code is used to analyze and simulate the nonlinear beam dynamics of the designed lattice. To speed up the lattice design flow, we parallelized the TRACY by MPI and developed a GUI by GTK+ to integrate the functions of TRACY and added a function of nonlinear optimization adapted from OPA, which is used to optimize the nonlinear driving terms by powell algorithm. The GUI is used for parameter input and data visualization. The procedures of nonlinear optimization and beam dynamics analysis are integrated and streamlined. Users do not need to write and compile the code any more. The results will be demonstrated in this report.  
 
MOPPD077 Studies for an Alternative LHC Non-Linear Collimation System collimation, proton, betatron, impedance 544
 
  • L. Lari, R.W. Assmann, V. Boccone, F. Cerutti, A. Mereghetti, R. Versaci, V. Vlachoudis
    CERN, Geneva, Switzerland
  • A. Faus-Golfe, L. Lari, J. Resta-López
    IFIC, Valencia, Spain
  
  Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program.
A LHC nonlinear Betatron cleaning collimation system would allow larger gap for the mechanical jaws, reducing as a consequence the collimator-induced impedance, which may limit the LHC beam intensity. In this paper, the performance of the proposed system is analyzed in terms of beam losses distribution around the LHC ring and cleaning efficiency in stable physics condition at 7TeV for Beam1. Moreover, the energy deposition distribution on the machine elements is compared to the present LHC Betatron cleaning collimation system in the Point 7 Insertion Region (IR). 		 
 
MOPPP057 Optimization of the Low-emittance Lattice of the APS Booster Synchrotron booster, lattice, emittance, injection 690
 
  • C. Yao, V. Sajaev, N. Sereno, H. Shang
    ANL, Argonne, USA
  
  Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06- CH11357.
The APS booster is a 7GeV electron synchrotron. Three lattices have been originally designed with a nominal beam emittance of 132, 109, and 92 nm, respectively. In the past we have mostly operated the booster with the 132 nm lattice because of its better stability. The lower-emittance lattices are not utilized. In early 2010 we upgraded the booster ramp correction and reduced the 360Hz current ripples of the ramp supplies. Current ramp errors have been significantly reduced. This raises our interest in running the low- emittance lattice to improve APS storage ring injection efficiency and reduce radiation losses. This report presents the optimization methods and measurement results of booster beam performance of the booster 92nm lattice. 		 
 
MOPPP061 Using RADIA to Model Superconducting Wigglers at the Canadian Light Source wiggler, insertion, insertion-device, vacuum 699
 
  • C.K. Baribeau, L.O. Dallin, M.J. Sigrist, W.A. Wurtz
    CLS, Saskatoon, Saskatchewan, Canada
  
  The Canadian Light Source operates two superconducting wigglers: a 2 Tesla, 63 pole wiggler, and a 4 Tesla, 27 pole wiggler. Both SCWs have a negative impact on the injection efficiency. Beam based measurements indicate a larger than expected sextupole moment, and the 4T wiggler produces a large horizontal tune shift. To better understand these effects, computer models were developed for the SCWs using the magnetic modelling software package, RADIA. The RADIA models accurately predict the wiggler on-axis field strength and vertical tune shift. By introducing physical misalignments, the models can produce sextupole moments of the same order of magnitude as the measured quantities. However, the modelled horizontal tune shift is orders of magnitude smaller than the 4T wiggler’s observed tune shift. Various model parameters were investigated for their effect on horizontal tune shift, but the cause of the 4T wiggler’s large horizontal tune shift remains unknown.  
 
TUOAA02 Focusing Charged Particle Beams Using Multipole Magnets in a Beam Transport Line multipole, 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 icon Slides TUOAA02 [2.032 MB]  
 
TUPPC003 Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors coupling, quadrupole, emittance, betatron 1152
 
  • A. Chancé, J. Payet
    CEA/DSM/IRFU, France
  • B. Dalena
    CEA/IRFU, Gif-sur-Yvette, France
  
  The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.  
 
TUPPC005 Optimization of the SIS100 Nonlinear Magnet Scheme for Slow Extraction extraction, octupole, lattice, dynamic-aperture 1158
 
  • A. Saa Hernandez, M.M. Kirk, D. Ondreka, N. Pyka, S. Sorge, P.J. Spiller
    GSI, Darmstadt, Germany
  
  The SIS100 superconducting synchrotron was initially planned mainly for fast extraction of protons and heavy ions. Due to the delay of the construction of the SIS300 synchrotron, SIS100 has to be able to provide slowly extracted heavy ion beams to the experiments. To improve the robustness of the slow extraction from SIS100, a lattice review was performed, resulting in an optimization of the nonlinear magnet scheme. In the original scheme the Hardt condition cannot be established due to a collapse of the dynamic aperture caused by the chromatic sextupoles. In the optimized scheme the positions of the chromatic sextupoles are modified and octupoles are employed to compensate the second order effects of these sextupoles. In addition, the number of resonance sextupole magnets is reduced. With the new scheme, the Hardt condition can be established, leading to higher extraction efficiency. The separatrix can be freely adjusted, and closed orbit control is improved.  
 
TUPPC014 Design Study of Nonlinear Optics for a Very Low-emittance Lattice of the SPring-8 II lattice, emittance, resonance, optics 1185
 
  • Y. Shimosaki, K.K. Kaneki, T. Nakamura, H. Ohkuma, J. Schimizu, K. Soutome, M. Takao
    JASRI/SPring-8, Hyogo-ken, Japan
  
  A feasibility of a very low-emittance storage ring has been studied for an upgrade project, SPring-8 II. Its ultimate goal is to provide a superior brilliance for 0.5 ~ 100 keV photons. A sextupole bend lattice with the natural emittance of 70 pmrad at 6 GeV has been examined as the first candidate*. The nonlinear optics has been optimized to enlarge the dynamic aperture by correcting nonlinear resonances based on an isolated resonance Hamiltonian with thick lens approximation, and by non-interleaved sextupole method. A genetic algorithm, which has been examined to improve the performance of the present SPring-8**, will be adopted for detailed optimization of the tunes and sextupole strength to adjust the non-interleaved scheme and to correct higher order resonances. The correction scheme of nonlinear optics and its results will be presented in detail.
*Y. Shimosaki et al., IPAC’11, TUOAB01, p. 942 (2011).
**Y. Shimosaki et al., "Optimization of Lower Emittance Optics for the SPring-8 Storage Ring", these proceedings.
 		 
 
TUPPC015 Local Modification of Lattice of a Long Straight Section for Installing Small Gap In-vacuum Undulators at SPring-8 lattice, betatron, dynamic-aperture, electron 1188
 
  • K. Soutome, T. Fujita, K. Fukami, K.K. Kaneki, C. Mitsuda, H. Ohkuma, M. Oishi, Y. Okayasu, S. Sasaki, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, Y. Taniuchi, C. Zhang
    JASRI/SPring-8, Hyogo-ken, Japan
  • M. Hasegawa, K. Kajimoto, T. Nakanishi
    SES, Hyogo-pref., Japan
  
  In the SPring-8 storage ring there are four magnet-free long straight sections (LSS) of about 30m. Recently we locally modified one of these sections by installing two quadrupole-triplets and divided it into three sub-sections. The vertical beta at the middle of each sub-section was lowered to 2.5m so that small gap in-vacuum undulators with a short period (min. gap: 5.2mm, period: 19mm) can be installed to build a high performance beamline for inelastic X-ray scattering. After modifying the lattice, however, the symmetry of the ring is lowered and, in general, it becomes difficult to keep sufficient dynamic aperture (DA) and momentum acceptance (MA). We solved this problem by combining the betatron phase matching, local chromaticity correction in LSS and cancellation of non-linear kicks due to sextupoles used for this correction. We could then recover DA and MA to almost the same level for the original one. The beam commissioning of the new lattice has successfully been finished, and from September 2011 it is used in user-operation. We will report our method of realizing a storage ring lattice having a very low symmetry and review the operation performance of the modified lattice.  
 
TUPPC023 Waist Corrections at the Interaction Point of ATF2 in the Presence of IPBSM Fringe Rotations and Input Beam Sigma13, Sigma24 coupling, simulation, quadrupole, alignment 1212
 
  • S. Bai, J. Gao
    IHEP, Beijing, People's Republic of China
  • P. Bambade
    LAL, Orsay, France
  
  The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam (or equivalently a σ13 correlation), as well as a σ24 correlation, can break the orthogonality in the main σ34 and σ32 waist corrections during the minimization and result in larger vertical beam sizes at IP. Both effects are studied, analytically and in simulation, and a practical procedure is suggested for diagnosing the presence of a residual fringe tilt, by measuring the influence of the horizontal waist correction on the minimum vertical beam size.  
 
TUPPC037 Update on LHeC Ring-Ring Optics insertion, optics, lattice, resonance 1242
 
  • M. Fitterer
    KIT, Karlsruhe, Germany
  • O.S. Brüning, H. Burkhardt, B.J. Holzer, J.M. Jowett
    CERN, Geneva, Switzerland
  • M. Klein
    The University of Liverpool, Liverpool, United Kingdom
  
  An update of the LHeC Ring-Ring optics is presented which accounts for chromatic corrections and more flexibility in the tune adjustment.  
 
TUPPC042 Effect of Field Errors in Muon Collider IR Magnets on Beam Dynamics multipole, dipole, 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 solenoid, injection, multipole, 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. 		 
 
TUPPC051 FACET Tolerances for Static and Dynamic Misalignment quadrupole, plasma, simulation, wakefield 1284
 
  • J.T. Frederico, M.J. Hogan, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
The Facility for Advanced Accelerator and Experimental Tests (FACET) at the SLAC National Accelerator Laboratory is designed to deliver a beam with a transverse spot size on the order of 10 μm x 10 μm in a new beamline constructed at the two kilometer point of the SLAC linac. Commissioning the beamline requires mitigating alignment errors and their effects, which can be significant and result in spot sizes orders of magnitude larger. Sextupole and quadrupole alignment errors in particular can introduce errors in focusing, steering, and dispersion which can result in spot size growth, beta mismatch, and waist movement. Alignment errors due to static misalignments, mechanical jitter, energy jitter, and other physical processes can be analyzed to determine the level of accuracy and precision that the beamline requires. It is important to recognize these effects and their tolerances in order to deliver a beam as designed. 		 
 
TUPPC058 Beam Energy Variation with Dipole Fault dipole, closed-orbit, simulation, lattice 1305
 
  • Y. Li, S. Krinsky
    BNL, Upton, Long Island, New York, USA
  
  Funding: Supported by Department of Energy Contract No. DE-AC02-98CH10886.
The effect of dipole faults and closed orbit correction on the beam energy is studied both analytically and numerically using the ELEGANT code. Motivated by top-off safety analysis, we consider the case of single dipole faults and study how large an error can be compensated by the closed orbit correction system before the beam is lost. 		 
 
TUPPC073 Frequency Map Analysis for SuperB resonance, lattice, dynamic-aperture, emittance 1341
 
  • S.M. Liuzzo, M.E. Biagini, P. Raimondi
    INFN/LNF, Frascati (Roma), Italy
  • T. Demma
    LAL, Orsay, France
  • Y. Papaphilippou
    CERN, Geneva, Switzerland
  
  The frequency map analysis is applied to the SuperB HER and LER lattices including the Final Focus, in order to understand the dynamic aperture limitation and provide insight for a working point optimization. In this respect, frequency and diffusion maps are evaluated applying random magnet misalignments and tilts, before and after correction of orbit, dispersion and coupling using Low Emittance Tuning techniques. The same analysis is performed for on and off momentum particles. The lattice properties are further investigated using working point scans and the correction of non linear resonance driving terms and amplitude detuning.  
 
TUPPC096 Optimization of the Dynamic Aperture for SPEAR3 Low-emittance Upgrade emittance, resonance, dynamic-aperture, optics 1380
 
  • L. Wang, X. Huang, Y. Nosochkov, J.A. Safranek
    SLAC, Menlo Park, California, USA
  • M. Borland
    ANL, Argonne, USA
  
  A low emittance upgrade is planned for SPEAR3. As the first phase, the emittance is reduced from 10nm to 7nm without addition magnets. A further upgrade with even lower emittance will require a damping wiggler. There is a smaller dynamic aperture for the lower emittance optics due to the stronger nonlinearity. A Multi-Objective Genetic Optimization (MOGA) code is used to maximize the dynamic aperture. Both the dynamic aperture and beam lifetime are optimized simultaneously. Various configurations of the sextupole magnets have been studied in order to find the best configuration. The betatron tune also can be optimized to minimize resonance effects. The optimized dynamic aperture increases 15% from the normal case and the life time increases from 15 hours to 17 hours. It is important that the increase of the dynamic aperture is mainly in the beam injection direction. Therefore the injection efficiency will benefit from this improvement.  
 
TUPPC099 Optimization of Chromaticity Compensation and Dynamic Aperture in MEIC Collider Rings ion, dynamic-aperture, octupole, collider 1389
 
  • F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang
    JLAB, Newport News, Virginia, USA
  • K.B. Beard
    Muons, Inc, Batavia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by US DOE STTR grant DE-SC0006272.
The conceptual design of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab relies on an ultra-small beta-star to achieve high luminosities of up to 1034 cm-2s−1. A low-beta insertion for interaction regions unavoidably induces large chromatic effects that demand a proper compensation. The present approach of chromatic compensation in the MEIC collider rings is based on a local correction scheme using two symmetric chromatic compensation blocks that includes families of sextupoles, and are placed in a beam extension area on both sides of a collision point. It can simultaneously compensate the first order chromaticity and chromatic beam smear at the IP without inducing significant second order aberrations. In this paper, we investigate both the momentum acceptance and dynamic aperture in the MEIC ion collider ring by considering the aberration effects up to the third order, such as amplitude dependent tune shift. We also explore the compensation of the third order effects by introducing families of octupoles in the extended beam area.
Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by US DOE STTR grant DE-SC0006272.
 		 
 
TUPPC101 A Model of the AGS Based on Stepwise Ray-Tracing Through the Measured Field Maps of the Main Magnets resonance, quadrupole, focusing, simulation 1395
 
  • Y. Dutheil, F. Méot, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Two dimensional mid-plane magnetic field maps of two of the main AGS magnets were produced, from Hall probe measurements, for a series of different current settings. The analysis of these data yielded the excitation functions and harmonic coefficients of the main magnets [BNL TN 424 & TN 429] which have been used so far in all the models of the AGS. The constant increase of computation power makes it possible today to directly use stepwise ray-tracing through these measured field maps with a reasonable computation time. We describe in detail how these field maps have allowed generation of models of the 6 different types of AGS main magnets, and how they are being handled with the Zgoubi ray-tracing code. We give and discuss a number of results so obtained regarding both beam and spin dynamics in the AGS, and provide comparisons with other numerical and analytical modeling methods. 		 
 
TUPPP002 GLASS Study of the Canadian Light Source Storage Ring Lattice dynamic-aperture, emittance, lattice, quadrupole 1602
 
  • W.A. Wurtz, L.O. Dallin
    CLS, Saskatoon, Saskatchewan, Canada
  
  GLASS is a technique for finding all potential operating points of a storage ring lattice by examining all possible configurations of the linear lattice. The Canadian Light Source (CLS) storage ring uses three quadrupole families, making it computationally efficient to use GLASS to study the lattice with unbroken symmetry. CLS does not employ harmonic sextupoles and has only two families of chromatic sextupoles. We can exhaust the sextupole degrees of freedom by requiring the horizontal and vertical chromaticities to be both zero. With no remaining free parameters in our lattice, it is possible to calculate dynamic aperture and momentum acceptance for select regions of interest uncovered by the GLASS scan. We find two regions with reasonable dynamic aperture and momentum acceptance: the region where we presently operate and a region that can be accessed by reversing the polarity of one quadrupole family.  
 
TUPPP011 Simulations of Fringe Fields and Multipoles for the ANKA Storage Ring Bending Magnets multipole, simulation, optics, 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 multipole, dynamic-aperture, 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.  
 
TUPPP024 Recent Progress on the MAX IV 1.5 GeV Storage Ring Lattice and Optics storage-ring, lattice, dipole, vacuum 1662
 
  • S.C. Leemann
    MAX-lab, Lund, Sweden
  
  Construction of the MAX IV facility started in 2010 and commissioning is expected to begin in 2014. Once completed, the facility will include two storage rings for the production of synchrotron radiation. The 3 GeV ring will house insertion devices for the production of x-rays, while the 1.5 GeV ring will serve UV and IR users. Recently, the lattice and optics of the 1.5 GeV storage ring have been modified as a result of detailed magnet and vacuum system design. This paper discusses the lattice and optics changes as well as their effects.  
 
TUPPP028 A Study of Girder Alignment with Survey Measurements In the Diamond Storage Ring survey, storage-ring, closed-orbit, insertion 1674
 
  • M. Apollonio, R. Bartolini, R.T. Fielder, W.J. Hoffman, J. Kay, I.P.S. Martin, B. Singh
    Diamond, Oxfordshire, United Kingdom
  
  Using a model of the Diamond storage ring which includes displacements and rotations of the 74 magnet girders an attempt has been made to correlate survey data with the corrector magnet (CM) strengths required for a zero orbit. We then use the model to deduce the most effective girder movements that will bring about a reduction in corrector strength. We describe the results of these studies, and suggest a test with a deliberately displaced girder and the effect on corrector strengths, aimed at enhancing our understanding of the system  
 
TUPPP033 Exploration of a Tevatron-sized Ultimate Storage Ring emittance, storage-ring, brightness, damping 1683
 
  • M. Borland
    ANL, Argonne, 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.
With the Tevatron now shut down and slated for decommissioning, it is only natural to think about other possible uses for the 6.3 km tunnel. Given that the brightness of electron storage rings naively scales as radius cubed, one exciting possibility is to build a so-called ultimate storage ring light source. This paper describes a somewhat speculative exploration of this idea, showing the potential for a storage ring x-ray source of unprecedented brightness. 		 
 
TUPPP068 Comparison of Compression Schemes for CLARA emittance, FEL, linac, cavity 1756
 
  • P.H. Williams, J.W. McKenzie
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • J.K. Jones, P.H. Williams
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory is proposed to be the UK’s national FEL test facility. The accelerator will be a ~250 MeV electron linac capable of producing short, high brightness electron bunches. The machine comprises a 2.5 cell RF photocathode gun, one 2 m and three 5 m normal conducting S-band (2998MHz) accelerating structures and a variable magnetic compression chicane. CLARA will be used as a test bed for novel FEL configurations. We present a comparison of acceleration and compression schemes for the candidate machine layout.  
 
TUPPR017 Nonlinear Post-Linac Energy Collimation System for the Compact Linear Collider collimation, luminosity, octupole, simulation 1846
 
  • J. Resta-López, A. Faus-Golfe
    IFIC, Valencia, Spain
  
  Funding: FPA2010-21456-C02-01
The post-linac energy collimation system of the Compact Linear Collider (CLIC) has been designed to provide protection of the Beam Delivery System (BDS) against off-energy and mis-steered beams. The conventional baseline design consists of a two stage spoiler-absorber scheme. The CLIC energy collimators are required to withstand the impact of a full bunch train. This condition makes the energy collimator design very challenging, since the collimators have to deal with a total beam power of 14 MW at nominal energy and intensity. The increase of the transverse spot size at the collimators using nonlinear magnets could be a potential solution to guarantee the survivability of the collimators. In this paper we present an alternative nonlinear optics design for the CLIC energy collimation system. Possibilities for its optimization are discussed in view of performance simulation results. 		 
 
TUPPR056 Parametric Study of the CLIC Damping Rings Delay Ring for Reaching Isochronicity Conditions dipole, damping, optics, quadrupole 1948
 
  • P. Zisopoulos, F. Antoniou, Y. Papaphilippou
    CERN, Geneva, Switzerland
  
  A delay ring in the CLIC damping rings complex is necessary for recombining the two trains to one with the nominal bunch separation of 0.5ns. The preservation of the longitudinal bunch distribution demands an optics design, which eliminates momentum compaction factor up to high order, allowing the delay ring to function under isochronous conditions. Taking into account thin lens approximation, a qualitative estimation of parameters of the cell that will be used in the delay ring, is given, so as to obtain isochronicity conditions. Considerations on the possibility of tuning the cell under those requirements are finally presented.  
 
TUPPR068 The Achromatic Telescopic Squeezing Scheme: Basic Principles and First Demonstration at the LHC optics, injection, insertion, quadrupole 1978
 
  • S.D. Fartoukh, R. De Maria, B. Goddard, W. Höfle, M. Lamont, G.J. Müller, L. Ponce, S. Redaelli, R.J. Steinhagen, M. Strzelczyk, R. Tomás, G. Vanbavinckhove, J. Wenninger
    CERN, Geneva, Switzerland
  • R. Miyamoto
    ESS, Lund, Sweden
  
  The Achromatic Telescopic Squeezing (ATS) scheme [1] is a novel squeezing mechanism enabling the production of very low β* in circular colliders. The basic principles of the ATS scheme will be reviewed together with its strong justification for the High-Luminosity LHC Project. In this context, a few dedicated beam experiments were meticulously prepared and took place at the LHC in 2011. The results obtained will be highlighted, demonstrating already the potential of the ATS scheme for any upgrade project relying on a strong reduction of β*.
[1] S. Fartoukh, "An Achromatic Telescopic Squeezing (ATS) Scheme For The LHC Upgrade," IPAC'11, WEPC037, p. 2088 (2001). 		 
 
TUPPR085 Recycler Chromaticities and End Shims for NOvA at Fermilab lattice, quadrupole, dynamic-aperture, dipole 2023
 
  • M. Xiao
    Fermilab, Batavia, USA
  
  In era of NOvA operation, it is planned to slip-stack six on six Booster proton batches in the Recycler ring for a total intensity of 5×1013 protons/cycle. During the slip-stacking, the chromaticities are required to be jumped from (-2,-2) to (-20,-20). However, they can only be adjusted to (-12,-12) from (-2,-2) using existing 2 families of powered sextupoles. On the other hand, the presently designed Recycler lattice for Nova replaces the 30 straight section with 8 “D-D half FODO cells”. We use 3 quads in a half-cell to obtain the working point under the limit of the feasible quad strength, and the maximum beta-function in this section cannot be less than 80 m. In this paper, we re-designed the end shims of the permanent magnets in the ring lattice with appropriate quadrupole and sextupole components to meet both chromaticity and tune requirements. We are able to use 2 quads in a half cell in RR30 straight section within feasible quad strength. The maximum beta-functions are also lowered to around 55 m. The dynamic aperture tracking has been done using MAD to simulate the scenario of beam injection into the Recycler ring for Nova.  
 
WEYA03 Overview of B-Factories emittance, injection, quadrupole, collider 2086
 
  • M.E. Biagini
    INFN/LNF, Frascati (Roma), Italy
  
  An overview of the two recently approved high luminosity B-Factories, the SuperB in Italy and the SuperKEKB in Japan, will be presented. The main design features to reach the very high luminosity requested and a status of progress in design and construction will be given.  
slides icon Slides WEYA03 [6.151 MB]  
 
WEPPP087 The Improvement and Test of Laser Positioning System for TPS Magnets Alignment Inspection laser, quadrupole, alignment, insertion 2915
 
  • M.L. Chen, J.-R. Chen, H.C. Ho, K.H. Hsu, W.Y. Lai, C.-S. Lin, C.J. Lin, H.C. Lin, H.M. Luo, S.Y. Perng, P.L. Sung, Y.L. Tsai, T.C. Tseng, H.S. Wang, M.H. Wu
    NSRRC, Hsinchu, Taiwan
  
  A Laser positioning system, consist of a laser, laser position sensing devices (PSD) module and two granite blocks, is developed for the alignment inspection of TPS (Taiwan Photon Source) quadrupole and sextupole magnets during installation on a girder. The PSD module is adapted on the pole center of magnet and is designed to stand for mechanical center of magnets. For high accuracy, eliminating the influence of magnets manufacturing errors between PSD module is a major work. The PSD is mounted on a precise diameter expansible jig to absorb the manufacturing errors. The real roundness of the expansible jig can keep under 3um when diameter is expanded 80um. The PSD position is adjusted and corrected in advance, and then the PSD module center can be identical to the ideal pole position of magnets on the girder within 15um. The magnet will be aligned and adjusted by laser position on PSD. This paper describes how to eliminate the measuring error caused by magnet manufacturing error and the detail of alignment inspection procedure of magnets during the installation on a girder.  
 
WEPPR052 Octupole Magnets for the Instability Damping at the J-PARC Main Ring octupole, damping, resonance, dynamic-aperture 3045
 
  • S. Igarashi, T. Koseki, K. Ohmi, M.J. Shirakata, H. Someya, T. Toyama
    KEK, Ibaraki, Japan
  • A. Ando
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  Octupole magnets have been installed for the instability damping at the J-PARC main ring. The transverse instability was observed during the injection and acceleration periods and caused the beam losses. The chromaticity tuning and bunch-by-bunch feedback system have been applied to suppress the instability. Octupole magnets were considered to create a larger amplitude dependent betatron tune shift and to supply additional option for the instability damping. The side effects of the dynamic aperture reduction and the resonances have been studied.  
 
WEPPR068 Mitigation of Electron Cloud Instabilities in the LHC Using Sextupoles and Octupoles electron, octupole, damping, resonance 3084
 
  • K.S.B. Li, G. Rumolo
    CERN, Geneva, Switzerland
  
  Coherent electron cloud instabilities pose a serious limitation for luminosity upgrades in the Large Hadron Collider (LHC) at CERN. In particular, when bunch spacings reach below 50 ns, electron cloud formation is enhanced which in turn drives beam instabilities. The beam can be stabilised by shifting the tune and by increasing the tune spread using sextupoles or octupoles, respectively. The resulting values for the chromaticity and the detuning parameters must be selected with care, however, in order not to run into head-tail instabilities or to considerably reduce the dynamic aperture. A simulation study has been launched to estimate the parameters necessary for stabilisation of the beam under the influence of electron clouds.  
 
THPPD007 ILSF Storage Ring Magnets quadrupole, dipole, multipole, 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.  
 
THPPD015 Character and Performance of Magnets for the TPS Storage Ring multipole, 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.  
 
THPPD019 Accurately Determining the Parameters of a Magnet Coil by 3D CAD Design controls 3539
 
  • N. Li
    LBNL, Berkeley, California, USA
  • C. Chen, H.J. Hu, J. Jin, W.Y. Wen, L. Yin
    SINAP, Shanghai, People's Republic of China
  
  Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231.
Traditionally, the average turn length and number of turns of a conventional magnet coil is roughly estimated during the magnet physical design. Based on these estimates, the resistance, water flow and overall dimensions of the coil are calculated. But for a complex coil shape, it is very difficult to determine how many turns a coil will have and, more importantly, specifically how it will be wound. In many cases, an engineer will use a scale model to do a winding trial, but the coil parameters, such as the conductor length and overall coil dimensions, still cannot be precisely determined. 3D CAD modeling was used for the design of the Advanced Light Source (ALS) combined function sextupole magnet coils. The winding procedures for 11 types of coils were all determined by the models. The resistances and water flow requirements of those coils were calculated from the 3D models, and those parameters were used as criteria for production quality control thereafter. This paper will introduce some basic modeling techniques that are useful for 3D CAD modeling of magnet coils. The coil data comparison between 3D model and true built coils will be introduced as well. 		 
 
THPPD021 SC Magnet Development for SIS100 at FAIR quadrupole, dipole, multipole, 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.  
 
THPPD038 Measurements of the Persistent Current Decay and Snapback Effect in Nb3Sn Accelerator Prototype Magnets at Fermilab dipole, quadrupole, injection, multipole 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.  
 
THPPD039 Magnetic Analysis of a Single-Aperture 11T Nb3Sn Demonstrator Dipole for LHC Upgrades dipole, injection, simulation, coupling 3596
 
  • B. Auchmann, M. Karppinen
    CERN, Geneva, Switzerland
  • V. Kashikhin, A.V. Zlobin
    Fermilab, Batavia, USA
  
  Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The planned upgrade of the LHC collimation system foresees additional collimators to be installed in the dispersion suppressor areas around points 2, 3, and 7. The necessary longitudinal space for the collimators could be provided by replacing some 8.33-T 15-m-long NbTi LHC main dipoles with shorter 11-T Nb3Sn dipoles compatible with the LHC lattice and main systems. To demonstrate this possibility, in 2011 Fermilab and CERN started a joint R&D program with the goal of building a 5.5-m-long twin-aperture dipole prototype suitable for installation in the LHC by 2014. The first step of this program is the development of a 2-m-long single-aperture demonstration dipole with the nominal field of 11 T at the LHC nominal current of ~11.85 kA and 60-mm bore with ~20% margin. This paper presents the results of magnetic analysis of the single-aperture Nb3Sn demonstrator dipole for the LHC collimation system upgrade. 		 
 
THPPD043 Radiation-tolerant Multipole Correction Coils for FRIB quadrupole, octupole, radiation, multipole 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.  
 
THPPD055 High Current Unipolar Magnet Power Supply System at the PLS-II Storage Ring power-supply, quadrupole, lattice, septum 3638
 
  • S.-C. Kim, J.Y. Huang, K.R. Kim, S.H. Nam, S. Shin, Y.G. Son, C.W. Sung
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Funding: This work is supported by the Ministry of Education, Science and Technology, Korea.
Lattice of the Storage Ring (SR) is changed from TDB to DBA, and beam energy is enhanced from 2.5 GeV to 3.0 GeV at the Pohang Light Source upgrade (PLS-II). At the PLS-II, Magnet Power Supplies (MPS) were newly designed according to magnet specification of the PLS-II. All MPSs are adopted switching type power conversion technology. High current unipolar MPSs for bending(BD), main-quadrupole(MQ), sextupole(ST) and septum(SP) magnet are parallel operation type of unit stack buck type power supply. Unit stack of unipolar MPS has capability maximum 250A and operation 10kHz. BD and MQ MPS are adopted four stack as each stack 90degree phase shift switching, and have capability maximum 1000 A. ST MPS is adopted two stack as each stack 180degree phase shift switching, and have capability maximum 500 A. SP MPS is adopted single, and have capability maximum 250 A. All unipolar MPSs are developed as full digital controller, embedded EPICS IOC and operated less than ± 10ppm current stability. In this paper, we report on the development and characteristics of the high current unipolar MPS for the PLS-II SR. 		 
 
THPPR055 Compact Gantry with Large Momentum Acceptance kicker, proton, octupole, diagnostics 4100
 
  • W. Wan, D. Robin, A. Sessler, C. Sun
    LBNL, Berkeley, California, USA
  
  Rotatable Ion Beam Cancer Therapy (IBCT) delivery systems or gantries are the largest features in an ion beam therapy facility. They weight 100+ tons and require large (~3 story) heavily shielded rooms to house them. Reducing the size of ion beam gantries using high field One disadvantage of superconducting magnets is the difficulty of changing the fields quickly in order to adjust the beam momentum to scan the depth of penetration. In this paper we present a design of a gantry consisting of many combined function superconducting magnets that have a large enough momentum acceptance (> pm 10%) such that the magnets do not need to be changed while changing the beam energy.