IPAC2012 - List of Keywords (dipole)

Paper	Title	Other Keywords	Page
MOXBP01	The First Two Years of LHC Operation	luminosity, proton, ion, emittance	1
	S. Myers CERN, Geneva, Switzerland
	The operational performance of the LHC machine both for proton and lead ion operation are reviewed for the period 2010 and up the present. The beam parameter path allowing the very high rate of collider performance is presented and discussed. The accelerator issues encountered and those somewhat surprisingly not encountered are also discussed. The short and longer term plans for the LHC are also briefly presented.
	Slides MOXBP01 [17.468 MB]

MOEPPB004	A Compact Ring Design with Tunable Momentum Compaction	damping, dynamic-aperture, quadrupole, emittance	82
	Y. Sun SLAC, Menlo Park, California, USA
	A storage ring with tunable momentum compaction has the advantage in achieving diﬀerent RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre- damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and ﬁne tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

MOEPPB014	Time Jitter Measurements in Presence of a Magnetic Chicane in the FERMI@elettra Linac	electron, linac, FEL, laser	109
	G. Penco, P. Craievich, S. Di Mitri, M.M. Milloch, F. Rossi ELETTRA, Basovizza, Italy
	Accurate and highly stable temporal synchronization between an electron bunch and a pulse from an external seed laser is one of the key requirements for successful operation of a seeded FEL in the XUV and soft x-ray regime. These requirements become more stringent when the electron bunch is longitudinally compressed to sub-ps durations in order to increase the current for more efficient FEL action. In this paper we present experimental measurements of the electron bunch arrival time jitter after the first magnetic compressor of FERMI@Elettra seeded FEL as a function of the compression factor. The experimental behavior of the pulse-to-pulse time jitter agrees both with results from tracking code simulations and with predictions from an analytical approach that takes into account the different sources of time jitter in FERMI, namely the photoinjector drive laser, the RF accelerating cavity phases and voltages, and fluctuations in the chicane bending magnet currents. We also present predictions for the expected arrival time jitter in the final configuration of FERMI that includes two bunch compressors and for which the synchronization requirement is of order 100 fs or better.

MOPPC001	Simulation of electron-cloud heat load for the cold arcs of the large hadron collider	electron, simulation, injection, photon	115
	G.H.I. Maury Cuna CINVESTAV, Mérida, Mexico G. Iadarola Naples University Federico II, Science and Technology Pole, Napoli, Italy G. Rumolo, F. Zimmermann CERN, Geneva, Switzerland
	The heat load due to the electron cloud in the Large Hadron Collider (LHC) cold arcs is a concern for its performance near and beyond nominal beam current. We report the results of simulation studies, which examine the electron-cloud induced heat load for different values of low-energy electron reflectivity and secondary emission yield at injection energy, as well as at beam energies of 4 TeV and 7 TeV, for two different bunch spacing: 25 ns and 50 ns. Benchmarking the simulations against heat-load observations at different beam energies and bunch spacing allows an estimate of the secondary emission yield in the cold arcs of the LHC and of its evolution as a function of time.

MOPPC009	Multipactor for E-cloud Diagnostics	electron, resonance, cyclotron, vacuum	139
	P. Costa Pinto, F. Caspers, P. Edwards, M. Holz, M. Taborelli CERN, Geneva, Switzerland
	Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed though a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic field. Preliminary result show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the event of a large scale coating production this technique will be a valuable resource for quality control.

MOPPC016	Combined Ramp and Squeeze at the Large Hadron Collider	optics, injection, quadrupole, collider	157
	S. Redaelli, M. Lamont, G.J. Müller, R. Tomás, J. Wenninger CERN, Geneva, Switzerland N. Ryckx EPFL, Lausanne, Switzerland
	In the first two years of operation of the CERN Large Hadron Collider (LHC), the betatron squeeze has been carried out at constant flat top energy of 3.5 TeV. Squeeze setting functions are separated from the energy ramp functions. This ensured a maximum flexibility during commissioning because stopping at all intermediate optics for detailed measurements was possible. In order to then improve the efficiency of the operational cycle, combining the ramp and squeeze has been considered. In this paper, the various possibilities for this scheme are reviewed, and proposals of optimized operational cycles with combined ramp and squeeze are presented for different energies. Results of beam tests are also discussed.

MOPPC028	Coherent Beam-Beam Effects Observation and Mitigation at the RHIC Collider	emittance, simulation, damping, coupling	193
	S.M. White, M. Bai, W. Fischer, Y. Luo, A. Marusic, M.G. Minty BNL, Upton, Long Island, New York, USA
	Funding: Work partially supported by Brookhaven Science Associates, LARP, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

MOPPC032	Injection and Broadband Matching for the PRISM Muon FFAG	injection, betatron, solenoid, target	202
	J. Pasternak, R. Chudzinski, A. Kurup Imperial College of Science and Technology, Department of Physics, London, United Kingdom J. Pasternak STFC/RAL, Chilton, Didcot, Oxon, United Kingdom A. Sato Osaka University, Osaka, Japan
	The next generation of lepton flavor violation experiments requires high intensity and high quality muon beams. Such conditions can be met using phase rotation of short muon pulses in an FFAG ring, as was proposed for the PRISM project. The very large initial momentum spread and transverse emittance of the muon beam poses a significant challenge for the injection system into the PRISM FFAG. Also, the matching optics between the solenoidal transfer channel and the ring needs to create a specific orbit excursion in the horizontal plane, suppress any vertical dispersion and produce good betatron conditions in both planes. Candidate geometries for the matching and injection systems are presented and their performances are tested in tracking studies.

MOPPC042	Higgs Boson Muon Collider Factory: h⁰, A, H Studies	collider, factory, solenoid, simulation	226
	D.B. Cline, X.P. Ding, J.L. Lederman UCLA, Los Angeles, California, USA
	With the recent hints of the Higgs boson from the LHC and a mass near 125 GeV/c we re-propose to study and build a muon collider Higgs factory to study the Higgs in the S channel. This was first proposed in 1992 by the first author. It is essential to study the Higgs boson for clues to new physics. The formation of the DOE MAP program, recent advances in 6D μ cooling methods, simulation, and targeting make this a feasible project to initiate at this time. This collider would fit into the FNAL site.

MOPPC043	Injection/Extraction of Achromat-based 6D Ionization Cooling Rings for Muons	injection, solenoid, kicker, extraction	229
	X.P. Ding, D.B. Cline UCLA, Los Angeles, California, USA J.S. Berg, H.G. Kirk BNL, Upton, Long Island, New York, USA A.A. Garren, F.E. Mills Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: This work was supported in part by the US Department of Energy in part under award numbers DE-FG02-92ER40695 (UCLA), DE-AC02-98CH10886 (BNL) and DE-FG02-07ER84855 (Particle Beam Lasers, Inc.). An achromat-based cooing ring using dipoles and solenoids is introduced and it can cool muons by large factors in six dimensions to achieve the necessary luminosity for a muon collider. The ring is designed with sufficient space in each superperiod for injection and extraction magnets. We estimate the parameters for the injection system into the solenoid-dipole ring cooler. We also present some simulations for injection/extraction system and discuss the injection/extraction requirements. Al Garren, J.S. Berg, D. Cline, X. Ding, H.G. Kirk, “Robust 6D μ± cooling using a solenoid-dipole ring cooler for a muon collider”, NIM A 654 (2011) 40-44.

MOPPC045	Scaled Electron Model of a Dogbone Muon RLA with Multi-pass Arcs	linac, electron, quadrupole, optics	235
	S.A. Bogacz, A. Hutton, G.A. Krafft, V.S. Morozov, Y. Roblin JLAB, Newport News, Virginia, USA K.B. Beard, R.P. Johnson Muons, Inc, Batavia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by USDOE STTR Grant DE-FG02-08ER86351. The design of a dogbone RLA with linear-field multi-pass arcs was earlier developed for accelerating muons for a future Neutrino Factory and Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over single pass or pulsed arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme in which a 4.35 MeV/c electron beam is injected in the middle of a 2.9 MeV/pass linac with two double-pass return arcs, and is accelerated to 17.4 MeV/c in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it feasible to utilize the existing technologies. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPPC053	Modeling of Bending Magnets for SIRIUS	simulation, multipole, 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	multipole, 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.

MOPPC063	Computation of the 2D Transverse Wake Function of an Electron Cloud for Different Parameters	electron, simulation, lattice, wakefield	280
	A. Markoviḱ, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by DFG under contract number RI 814/20-2. A PIC simulation of the interaction of a positive charged bunch with an e-cloud yields the wake kick from the electrons on the tail particles of the bunch. The wake is induced from a certain offset in the transverse position of the head parts of the bunch which perturb the electron distribution. Such a pre-computed wake functions of each offset part of the bunch are forming a matrix which could be used for investigating single bunch stability under several assumptions. In this paper we investigate the linear scalability of the kick with the offset value. Furthermore we investigate the wake values for different realistic electron densities. Another important parameter for realizing the single bunch stability simulation is the optimal number of bunch slices in longitudinal direction. Here we study the thickness of the slices in conjunction with the mobility of the electrons around the beam axis.

MOPPC081	Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field	electron, cavity, simulation, site	325
	G.V. Romanov, V.S. Kashikhin Fermilab, Batavia, USA
	In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low-Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of an RF cavity with beryllium windows in a solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to the RF electric field significantly modifies the performance of RF cavities. However, the magnetic field in a Helical Cooling Channel has a strong dipole component in addition to a solenoidal one. The dipole component essentially changes electron motion in a cavity compared to a pure solenoidal case, making dark current less focused at field emission sites. The simulation of a dark current dynamic in HCC performed with CST Studio Suite is presented in this paper.

MOPPD033	Strong-focusing Cyclotron - High-current Applications	cyclotron, proton, focusing, cavity	436
	P.M. McIntyre, S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, J.N. Kellams, T.L. Mann, A.D. McInturff, N. Pogue, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: This work is supported by grants from the State of Texas (ASE) and from the Mitchell Family Foundation. Quadrupole focusing channels are integrated into the pole faces of a superconducting sector cyclotron, to enable control of the betatron tunes for all orbits. This provision makes it possible to lock the tunes to desired values for all orbits, thereby eliminating resonance crossing and facilitating local orbit bumps for injection and extraction. Optical control is of particular importance for applications where higher beam current is desired, for ADS fission drivers, for spallation neutron sources, and for medical isotope production.

MOPPD041	Beam Loss Protection for a 2.3 Megawatt LBNE Proton Beam	quadrupole, proton, power-supply, target	454
	R.M. Zwaska, S.C. Childress, A.I. Drozhdin, N.V. Mokhov, I.S. Tropin Fermilab, Batavia, USA
	Funding: U.S. Department of Energy. Severe limits are required for allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6·10¹⁴ protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that localized loss of a single beam pulse at 2.3 MW will result in a destructive event: beam pipe failure, damaged magnets and high levels of residual radiation inside the tunnel. A sustained full beam loss would be catastrophic. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

MOPPD043	Novel Muon Beam Facilities for Project X at Fermilab	proton, target, linac, electron	457
	C.M. Ankenbrandt, R.J. Abrams, T.J. Roberts, C. Y. Yoshikawa Muons, Inc, Batavia, USA D.V. Neuffer Fermilab, Batavia, USA
	Innovative muon beam concepts for intensity-frontier experiments such as muon-to-electron conversion are described. Elaborating upon a previous single-beam idea, we have developed a design concept for a system to generate four high quality, low-energy muon beams (two of each sign) from a single beam of protons. As a first step, the production of pions by 1 and 3 GeV protons from the proposed Project X linac at Fermilab is being simulated and compared with the 8-GeV results from the previous study.

MOPPD050	Dipole Magnet Design for a Bunch Compressor	neutron, linac, proton, focusing	478
	T. Kanesue, L.P. Chau, O. Meusel, D. Noll, U. Ratzinger IAP, Frankfurt am Main, Germany
	The FRANZ-ARMADILLO is a Mobley type bunch compressor system at the pulsed intense neutron source FRANZ, under construction at Frankfurt University. The FRANZ-ARMADILLO compresses 9μbunches of a 150 mA, 2 MeV proton beam accelerated by a 175 MHz linac into one short pulse of 1 ns pulse length with 250 kHz repetition rate. In the bunch compressor, two homogeneous dipole magnets and two gradient dipole magnets guide theμbunches, separated by a 5 MHz RF-kicker on individual tracks. The flight path length of theμbunches are determined based on the bunch center velocity and the linac frequency for the longitudinal bunch compression. The gradient dipole magnets provide individual magnetic fields and edge focusing forces to everyμbunch. For the center trajectory, the required parameters are a magnetic field density of 509.2 mT, bending angle of 78.27 deg, and bending radius of 404.5 mm. To satisfy all specifications, field clamps, shims, and chamfer cut will be adopted. The result of the gradient dipole magnet design and the expected performance based on beam dynamics studies will be presented.

MOPPD057	CERN PSB-to-PS Transfer Modifications for the 2 GeV Upgrade	injection, optics, quadrupole, septum	493
	W. Bartmann, J. Borburgh, S.S. Gilardoni, B. Goddard, A. Newborough, S. Pittet, R. Steerenberg CERN, Geneva, Switzerland C.H. Yu IHEP, Beijing, People's Republic of China
	Within the frame of the CERN PS Booster (PSB) energy upgrade from 1.4 to 2 GeV, the PSB to PS transfer line will be adapted for pulse-to-pulse modulated operation. A modified lattice is presented including a re-design of the switching dipole between ISOLDE and PS and additional collimators to protect the PS injection septum. Optics solutions optimized for small emittance LHC beams as well as for the large emittance high-intensity beams are shown.

MOPPD063	A 180 MeV Injection System for the ISIS Synchrotron	injection, synchrotron, electron, simulation	511
	B. Jones, D.J. Adams, M.C. Hughes, S.J.S. Jago, H. V. Smith, C.M. Warsop, R.E. Williamson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It operates at 50 Hz accelerating 3x10¹³ protons per pulse via a 70 MeV H⁻ linac and an 800 MeV proton synchrotron, delivering a mean beam power of 0.2 MW. A favoured first step to upgrade ISIS towards the megawatt regime is replacement of the linac with a new 180 MeV injector. Studies of this upgrade, which aims to increase mean beam power up to 0.5 MW are continuing. This paper summarises designs for a new injection region including beam dynamics and related hardware.

MOPPD071	Error Localization in RHIC by Fitting Difference Orbit	storage-ring, feedback, closed-orbit, optics	526
	C. Liu, M.G. Minty, V. Ptitsyn 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. Many errors in an accelerator are evidenced as transverse kicks to the beam, which distort the beam trajectory. Therefore, the information of the errors are imprinted in the distorted orbits, which are different from what would be predicted by the optics model. In this paper, we introduce an algorithm for fitting the orbit based on an on-line optics model. We apply the algorithm to localize the location of the elusive source of vertical diurnal variations observed in RHIC, and analyze D0/Dx errors in local coupling measurement.

MOPPD084	Optimization of Extinction Efficiency in the 8-GeV Mu2e Beam Line	proton, target, background, alignment	565
	I.L. Rakhno, A.I. Drozhdin, C. Johnstone, N.V. Mokhov, E. Prebys Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. A muon-to-electron conversion experiment at Fermilab is being designed to probe for new physics beyond the standard model at mass scales up to 10000 TeV. The advance in experimental sensitivity is four orders of magnitude when compared to existing data on charged lepton flavor violation. The critical requirement of the experiment is the ability to deliver a proton beam contained in short 100-ns bunches onto a muon production target, with an inter-bunch separation of about 1700 ns. In order to insure the low level of background at the muon detector consistent with the required sensitivity, protons that reach the target between bunches must be suppressed by an enormous factor, 109. This paper describes the results of numerical modeling with STRUCT and MARS codes for a beam line with a collimation system,** and optics that achieves an experimental extinction factor of one per billion. * R.M. Carey et al., Mu2e Proposal, Fermilab (2008). W. Molzon, “Proton Beam Extinction,” MECO-EXT-05-002 (2005). * E. Prebys, Mu2e-doc-534 (2009), http://mu2e-docdb.fnal.gov.

MOPPP013	Passive Momentum Spread Compensation by a “Wakefield Silencer”	wakefield, electron, simulation, FEL	598
	S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York, USA W. Gai, A. Zholents ANL, Argonne, USA
	Funding: DOE SBIR. We report an observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 5 cm long dielectric loaded waveguide structure. The experiment was conducted at the ATF facility at BNL according to a concept dubbed a wakefield silencer originally developed at the ANL AATF, which involves defining the electron bunch peak current distribution and selecting the optimal waveguide structure suitable for chirp cancellation using self-induced wakefields of the electron bunch. Our experiment has been carried out with a 247 micron triangular beam with a 200 keV energy spread, which was reduced by a factor of three to approximately 70 keV by passing it through a 0.95 THz dielectric-lined structure. Theoretical analysis supports the experimental results. Further exploration and applications of this technique will be discussed as well. M. Rosing, J. Simpson, Argonne Wakefield Accelerator Note, WF -144 (1990).

MOPPP033	Diagnostics at PITZ 2.0 Beamline: Status and New Developments	emittance, electron, diagnostics, FEL	634
	M. Otevřel, A. Donat, H.-J. Grabosch, M. Groß, L. Hakobyan, H.M. Henschel, L. Jachmann, M. Khojoyan, G. Klemz, W. Köhler, G. Koss, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, H. Leich, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, J. Meissner, A. Oppelt, M. Penno, B. Petrosyan, M. Pohl, S. Riemann, M. Sachwitz, B. Schöneich, J. Schultze, A. Shapovalov, F. Stephan, F. Tonisch, G. Vashchenko, L.V. Vu, T. Walter, S. Weisse, R.W. Wenndorff, M. Winde DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria N.I. Brusova, L.V. Kravchuk, V.V. Paramonov RAS/INR, Moscow, Russia A. Gonnin, M. Joré, B. Mercier, C. Prevost, A. Variola LAL, Orsay, France I.I. Isaev MEPhI, Moscow, Russia Ye. Ivanisenko IERT, Kharkov, Ukraine D. Richter HZB, Berlin, Germany S. Rimjaem Chiang Mai University, Chiang Mai, Thailand A.A. Zavadtsev, D.A. Zavadtsev Nano, Moscow, Russia
	The main aim of the Photo Injector Test Facility at DESY, Zeuthen (PITZ) site is to develop and test an FEL photo injector system capable of producing high charge short electron bunches of lowest possible transverse emittance to allow optimum FEL performance. The last major beamline upgrade realized in the second half of the year 2011 completed the evolution of the PITZ setup ongoing since 2005. The most recent upgrades include the installation of a new RF deflecting cavity - a prerequisite for longitudinal emittance and high resolution slice emittance measurements and installation of a new dispersive section for longitudinal phase space diagnostics of the high energy electron bunches. The paper will give an overview on electron beam diagnostics at PITZ, including the above mentioned upgrades.

MOPPP034	Simulation of the Longitudinal Phase Space Measurement with Transverse Deflecting Structure at PITZ	cavity, electron, emittance, simulation	637
	D. Malyutin, M. Krasilnikov, M. Otevřel, F. Stephan DESY Zeuthen, Zeuthen, Germany
	The main goal of the Photo Injector Test facility at DESY, Zeuthen site, (PITZ) is the development, optimization and detailed characterization of electron sources for the short wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL. For successful operation of such type of FELs the injector must provide high quality electron bunches, enough short in duration with high charge and small transverse and longitudinal emittance values. Installation of the Transverse Deflecting Structure (TDS) at PITZ will provide the possibility for detailed characterization of bunch temporal profile, bunch transverse slice emittance and longitudinal phase space. The TDS cavity is currently installed at the PITZ beamline, and commissioning of the whole TDS system is expected in the spring 2012. In the first part of the paper the basic principles of the TDS deflector are described. In the next section, simulation of measurements by TDS cavity applied to the PITZ beam parameters is presented. The temporal resolution for different types of measurements is discussed. Systematic limitations are estimated.

MOPPP036	Progress in Reducing the Back-bombardment Effect in the ITC-RF gun for t-ACTS Project at Tohoku University	cathode, electron, gun, simulation	643
	X. Li, H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, T. Muto, K. Nanbu, Y. Tanaka Tohoku University, Research Center for Electron Photon Science, Sendai, Japan F. Miyahara KEK, Ibaraki, Japan
	An ITC (independently tunable cells) thermionic RF gun* has been developed to produce sub-picosecond electron pulses as part of the injector for coherent terahertz radiation at Tohoku University. Both experiments and simulations have shown that the back-bombardment (B.B.) effect on the LaB6 cathode is a serious issue for option. A numerical model has been developed to evaluate the temperature increase of the cathode due to B.B. in which a 2D equation for heat conduction is solved by taking the back-streaming electrons into account. Using this model we have studied the possibility of suppressing the B.B. by employing dipole field and optimization of the cathode radius, compared with experimental data. Other methods and the prospect of the RF gun will also be reported. * H. Hama et al., New J. Phys. 8 (2006) 292

MOPPP052	Booster Synchrotron for SIRIUS Light Source	booster, injection, extraction, emittance	679
	F. H. de Sá, L. Liu, A.R.D. Rodrigues LNLS, Campinas, Brazil
	A full energy 3 GeV booster for the new Brazilian Synchrotron Light Laboratory (LNLS) third generation light source, SIRIUS, is proposed. The 144 m circumference magnetic lattice consists of two super-periods of FODO cells with defocusing dipoles and focusing quadrupoles. The optics provides a low emittance beam of 38 nm.rad at 3 GeV, high horizontal betatron and zero dispersion functions at straight sections. The top-up operation requires a cycling energy ramp from 150 MeV to 3 GeV with repetition rate of 1 Hz.

MOPPP053	Failure Mode Analysis in Preparation for Top-up Injection at the Canadian Light Source (CLS)	injection, storage-ring, kicker, simulation	682
	L.O. Dallin CLS, Saskatoon, Saskatchewan, Canada
	Top-up injection involves injecting beam with beamline safety shutters open. Consequently it is extremely important that no electrons enter the beamlines where they could be a potential safety hazard to beamline personnel. To investigate the likelihood that electrons could exit the storage ring various failure mode simulations have been done. The approach is to account for all possible injection trajectories and show that these particles will be intercepted by various storage ring apertures before they reach an amplitude that is deemed unsafe. This amplitude was chosen to be 50 mm and the field roll-off of all storage ring magnets were defined to this amplitude. Failure modes invested included injection kicker failures, uncorrected misalignment errors, off-energy injection and shorted storage ring magnet coils. Errors that would render it impossible to store beam were not investigated. As some particles reached amplitudes beyond the safe limit measures have been devised to eliminate these unsafe scenarios.

MOPPP060	Top-Off Mode of Operations: Setting Limits on the Extracted Beam Energy by Constraining Currents of Multiple Booster Dipole Power Supplies.	booster, extraction, lattice, injection	696
	T.V. Shaftan BNL, Upton, Long Island, New York, USA
	In preparation for top-off mode of the NSLS-II operations we have studied impact of errors in the dipole power supply current on the extracted beam energy, which has to be interlocked so to satisfy the safety requirements. The NSLS-II booster dipole circuits are combined into 3 independent PS circuits, which adds complexity to the analysis of the extracted beam energy limits.

MOPPR057	Development of a Cavity Beam Position Monitor for CLIC	cavity, linac, coupling, factory	915
	F.J. Cullinan, S.T. Boogert, N.Y. Joshi, A. Lyapin JAI, Egham, Surrey, United Kingdom E. Calvo, N. Chritin, F. Guillot-Vignot, T. Lefèvre, L. Søby CERN, Geneva, Switzerland A. Lunin, M. Wendt, V.P. Yakovlev Fermilab, Batavia, USA S.R. Smith SLAC, Menlo Park, California, USA
	The Compact Linear Collider (CLIC) project presents many challenges to its subsystems and the beam diagnostics in particular must perform beyond current limitations. The requirements for the CLIC main beam position monitors foresee a spacial resolution of 50 nm while delivering a 10 ns temporal resolution within the bunch train. We discuss the design of the microwave cavity pick-up and associated electronics, bench top tests with the first prototype cavity, as well as some of the machine-specific integration and operational issues.

MOPPR069	Use of Waveguide and Beam Pipe Probes as Beam Position and Tilt Monitoring Diagnostics with Superconducting Deflecting Cavities	cavity, HOM, monitoring, simulation	945
	X. Sun, T.G. Berenc, G. Decker, G.J. Waldschmidt, G. Wu 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. Waveguide and beam pipe field probes associated with a superconducting deflecting cavity are explored as beam position and tilt monitoring diagnostics. The superconducting deflecting cavity will be used for the Short-pulse X-rays (SPX) in the Advanced Photon Source (APS) upgrade project. Microwave Studio will be used to simulate the techniques of detecting the fields excited by the beam passing through the cavity and determining how close the beam is on electrical center.

MOPPR088	Cavity BPM for 1300 MHz Cryomodules	cavity, coupling, wakefield, cryomodule	993
	N. Barov, D.J. Newsham, D. Wu Far-Tech, Inc., San Diego, California, USA
	Funding: Work supported by DOE grant DE-SC00004498 A cavity BPM for 1300 MHz cryomodules is under development by FAR-TECH, Inc. The BPM is capacitively loaded to fit in a small area, and uses a novel coupling scheme which further cuts down space requirements. We discuss status of the fabrication, and eventual plan to test the diagnostic at the ANL Wakefield Accelerator facility.

TUXB01	Progress Towards Ultimate Storage Ring Light Sources	emittance, brightness, electron, wiggler	1035
	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. Developments such as the low emittance NSLS-II storage ring, followed by the even lower emittance MAX-IV ring, demonstrate that the technology of storage ring light sources has not reached full maturity. Indeed, these new sources are paving the way toward realizing diffraction-limited angstrom-wavelength storage ring light sources in the not-too-distant future. Our discussion begins with a review of recent trends and developments in storage ring design. We then survey on-going work around the world to develop concepts and designs for so-called "ultimate" storage ring light sources.
	Slides TUXB01 [3.442 MB]

TUOAC02	Development of HTS Magnets	superconductivity, resonance, synchrotron, neutron	1095
	K. Hatanaka, M. Fukuda, N. Hamatani, N. Izumi, K. Kamakura, T. Saito, H. Ueda, Y. Yasuda, T. Yorita RCNP, Osaka, Japan T. Kawaguchi KT Science Ltd., Akashi, Japan
	A quarter of a century has passed since the discovery of high-temperature superconductor (HTS) materials in 1986. Although many prototype devices using HTS wires have been developed, these applications are presently rather limited in accelerator and beam line facilities. We have investigated the performance of HTS wires applied for magnets excited by alternating current (AC) as well as direct current (DC) for a decade. In order to check feasibilities of pulse magnets using HTS wire, we have fabricated a super-ferric dipole magnet to be operated by lumping currents. Upper and lower coil consists of 3 double pancakes of 200 turns. Critical currents were measured of wire measured at 77K. Self-field Ic of wire was higher than 160A. Ic values of double pancakes were 60-70A. After stacking, they were 47A and 51A for the upper and lower coil, respectively. Cooling tests were successfully done and the Ic values were measured to be 280A at 20K. Performance tests are ongoing in the pulse mode operation.
	Slides TUOAC02 [5.252 MB]

TUOAC03	Status of a Single-Aperture 11 T Nb3Sn Demonstrator Dipole for LHC Upgrades	collimation, status, magnet-design, lattice	1098
	A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, R. Bossert, G. Chlachidze, V. Kashikhin, A. Nobrega, I. Novitski, D. Turrioni, R. Yamada Fermilab, Batavia, USA B. Auchmann, M. Karppinen, L. Oberli, L. Rossi, D. Smekens CERN, Geneva, Switzerland
	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 includes two additional collimators to be installed in the dispersion suppressor areas of points 2, 3 and 7. The necessary longitudinal space for the collimators could be provided by replacing some 8.33 T NbTi LHC main dipoles with 11 T dipoles based on Nb3Sn superconductor and compatible with the LHC lattice and main systems. To demonstrate t his possibility Fermilab and CERN have started in 2011 a joint R&D program with the goal of building by 2014 a 5.5-m long twin-aperture dipole prototype suitable for installation in the LHC. 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 describes the design, construction and test results of the single-aperture Nb3Sn demonstrator model for the LHC collimation system upgrade.
	Slides TUOAC03 [5.812 MB]

TUOBC03	Experimental Measurements of e-Cloud Mitigation using Clearing Electrodes in the DAΦNE Collider	positron, vacuum, wiggler, electron	1107
	D. Alesini, T. Demma, A. Drago, A. Gallo, S. Guiducci, C. Milardi, P. Raimondi, M. Zobov INFN/LNF, Frascati (Roma), Italy S. De Santis LBNL, Berkeley, California, USA
	Recently the electron-positron collider DAΦNE has started delivering luminosity to the KLOE-2 experiment. For this run special metallic electrodes for e-cloud clearing were installed in all the dipole and wiggler magnets of the collider positron ring. Experimental measurements of the effectiveness of the electrodes in the mitigation of the e-cloud effects in the positron beam have been done showing an impressive effectiveness of these devices in the cure of the e-cloud effects in the positron beam. In particular the electrodes allow reducing the vertical beam size increase, the growth rate of transverse instabilities and the tune shifts induced by the electron cloud. Frequency shifts measurements of the vacuum chamber resonances switching on and off the electrodes have also been done showing their effect in the reduction of the electron cloud density. In this paper we summarize the results of all our observations and the experimental measurements of the e-cloud suppression with these electrodes.
	Slides TUOBC03 [2.825 MB]

TUEPPB008	Status Report on the Iranian Light Source Facility Project	storage-ring, booster, cavity, synchrotron	1131
	J. Rahighi, H. Ajam, R. Aslani, S. Fatehi, H. Ghasem, M.R. Khabazi, R. Safian, E. Salimi, A. Shahveh IPM, Tehran, Iran E. Ahmadi, M. Jafarzadeh, H.B. Jalali, M. Moradi, S. Pirani, M. Rahimi, A. Sadeghipanah, F. Saeidi, Kh.S. Sarhadi, A. Shahverdi ILSF, Tehran, Iran D. Einfeld CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The Iranian Light Source Facility Project (ILSF) is a 3rd generation light source with an energy of 3 GeV,a full energy injector and a 100 MeV linac as preinjector. For storage ring, booster synchrotron and linac including the transfer lines, a draft design has been completed and will be presented. The storage ring has an emittance of 3.3 nm-rad, a circumference of 297.6 meters with an overall of 32 straight sections of different lengths. The booster synchrotron has a circumference of 197 meters and emittance of 35nm-rad. For the booster synchrotron a new lattice is proposed. The linac is a conventional 150 MeV accelerator. The different accelerator components, magnets, girders, power supplies, vacuum systems etc. are in the design phase. State of the art design for different components is employed through international collaboration.

TUPPC004	Study of a Lattice with a Lower Emittance at SOLEIL	emittance, lattice, optics, betatron	1155
	R. Nagaoka, P. Brunelle, A. Nadji, L.S. Nadolski SOLEIL, Gif-sur-Yvette, France
	The paper introduces the first preliminary feasibility study made at SOLEIL towards a possible future upgrade of the lattice in furthermore reducing the horizontal emittance, so to raise the storage ring performance. The approach taken is to employ whatever emittance reduction methods available, by respecting the given constraints on the lattice structure and the optics, particularly the circumference, insertion device straights, the required optics behavior as well as its tunability. Specifically, the possibility of introducing superbends into the double bend lattice is pursued, which are beneficial to hard X-ray users and could simultaneously help reducing the emittance thanks to its longitudinally varying field profile. Although the present study shall mainly focus on the linear properties of the optical solutions found, optimization of nonlinear optics is also discussed in view of the large dependence of the latter on the former.

TUPPC006	CW Energy Upgrade of the Superconducting Electron Accelerator S-DALINAC	recirculation, linac, simulation, extraction	1161
	M. Kleinmann, J. Conrad, R. Eichhorn, F. Hug, N. Pietralla TU Darmstadt, Darmstadt, Germany
	Funding: This work is supported by the DFG through SFB 634. The S-DALINAC is a superconducting recirculating electron accelerator with maximum design energy of 130 MeV operating in cw at 3 GHz. Even so the gradients of the superconducting cavities are well above design, their design quality factor of 3*10⁹ have not been reached so far. Due to the limited cooling power of the cryo-plant being 120 W, the final energy achievable in cw operation is around 85 MeV, currently. In order to provide a cw beam with the designed final energy in the future, the installation of an additional recirculation path is projected and to be finished by 2013. We review the design constraints related to the existing beam lines, report in detail on the magnet design (being the key issue) and the lattice calculations for the additional recirculation path.

TUPPC012	Optics of Extraction Lines at CNAO	proton, ion, extraction, septum	1179
	E. Bressi, L. Falbo, C. Priano, M. Pullia CNAO Foundation, Milan, Italy C. Biscari INFN/LNF, Frascati (Roma), Italy
	The CNAO (National Center for Oncological Hadrontherapy), is the first Italian center for deep hadrontherapy with proton and carbon ion beams, treating patients since fall 2011. The beam is delivered to the patient through a high energy transfer line (HEBT). The line is equipped with a horizontal switching dipole that carries the beam in three treatment rooms and a vertical switching dipole that allows a vertical delivery of the beam in the central treatment room. The CNAO HEBT commissioning has been carried out using proton and Carbon beams in the full range of energies: 60 to 250 MeV/u for protons, 120 to 400 MeV/u for Carbon ions. Optimization of the beam lines setup has been carried out for few energies, applying beam magnetic rigidity scaling for the full range in steps of the order of 1 MeV. The scaling has proven to be satisfactory for most elements, and only minor adjustments in the initial part of the line were needed to fulfill tolerances in all the range. Repeatability of magnetic settings is supported by measurements along the lines. Finally the results in terms of beam dimensions, beam transmission and beam position at the patient position are presented.

TUPPC036	Integration with the LHC of Electron Interaction Region Optics for a Ring-ring LHeC	quadrupole, proton, electron, optics	1239
	L.N.S. Thompson Cockcroft Institute, Warrington, Cheshire, United Kingdom R. Appleby UMAN, Manchester, United Kingdom N.R. Bernard ETH, Zurich, Switzerland H. Burkhardt, B.J. Holzer CERN, Geneva, Switzerland M. Fitterer KIT, Karlsruhe, Germany M. Klein The University of Liverpool, Liverpool, United Kingdom P. Kostka DESY Zeuthen, Zeuthen, Germany
	The Large Hadron Electron Collider (LHeC) project is a proposal to study e-p and e-A interactions at the LHC. One design uses an electron synchrotron to collide a 60GeV e± beam with the 7TeV proton beam. Designing a new accelerator around the existing LHC machine poses unique challenges, particularly in the interaction region (IR). The electron beam must be quickly separated from the proton beam after the interaction point (IP) to avoid beam-beam effects, while not significantly reducing luminosity or producing large amounts of synchrotron radiation. The proton beam must pass through the electron optics, while the electron beam must avoid the proton optics. The long straight section requires bending in both planes to counteract the IP crossing angle and to displace the beam vertically from the electron machine to the proton IP. An achromatic bending scheme is used in the vertical plane to eliminate dispersion at the IP and provide an optics which is well matched to the LHeC ring lattice. The interaction region and long straight section design is presented and detailed, and the design process and principles discussed.

TUPPC039	Synchrotron Radiation Studies for a Ring-Ring LHeC Interaction Region and Long Straight Section	electron, proton, quadrupole, synchrotron	1248
	L.N.S. Thompson Cockcroft Institute, Warrington, Cheshire, United Kingdom R. Appleby UMAN, Manchester, United Kingdom N.R. Bernard ETH, Zurich, Switzerland O.S. Brüning, B.J. Holzer CERN, Geneva, Switzerland M. Klein The University of Liverpool, Liverpool, United Kingdom P. Kostka DESY Zeuthen, Zeuthen, Germany B. Nagorny DESY, Hamburg, Germany
	The Large Hadron Electron Collider project is a proposal to study e-p and e-A interactions at the LHC. In the design for an electron synchrotron (alternative designs for a linac are also under development), a 60GeV e± beam is collided with a 7TeV LHC proton beam to produce TeV-scale collisions. Despite being much lower energy than the proton beam, the electron beam is high enough energy to produce significant amounts of synchrotron radiation (SR). This places strong constraints on beam optics and bending. In particular challenges arise with the complex geometry required by the long straight section (LSS) and interaction region (IR). This includes the coupled nature of the proton and electron optics, as SR produced by the electron beam must not be allowed to quench the superconducting proton magnets or create problems with beam-gas backgrounds. Despite this, the electron beam must be deflected significantly within the IR to produce sufficient separation from the proton beam.

TUPPC040	Model Calibration and Optics Correction Using Orbit Response Matrix in the Fermilab Booster	booster, optics, acceleration, coupling	1251
	M.J. McAteer, S.E. Kopp The University of Texas at Austin, Austin, Texas, USA V.A. Lebedev, E. Prebys Fermilab, Batavia, USA A.V. Petrenko BINP SB RAS, Novosibirsk, Russia
	A beam-based method of optical model calibration using the measured orbit response matrix, known as the LOCO method, was successfully applied to Fermilab's rapid-cycling Booster synchrotron. Orbit responses were measured by individually changing the strength of each dipole corrector throughout the acceleration cycle, and dispersion was measured by changing the beam's radial offset. The model calibration procedure revealed large calibration errors for all elements in the Booster's recently-installed multipole corrector packages and beam position monitors. The resulting model was used to correct coupling and beta beating.

TUPPC041	A 3 TeV Muon Collider Lattice Design	quadrupole, emittance, lattice, collider	1254
	Y. Alexahin, E. Gianfelice-Wendt Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy A new lattice for 3 TeV c.o.m. energy with β^=5mm was developed which follows the basic concept of the earlier 1.5 TeV design but uses quad triplets for the final focus in order to keep the maximum magnet strength and aperture about the same as in 1.5 TeV case. Another difference is employment of combined-function magnets with the goal to lower heat deposition in magnet cold mass and to eliminate regions without bending field which produce “hot spots” of neutrino radiation that can be an issue at higher energy. The proposed lattice is shown to satisfy the requirements on luminosity, dynamic aperture and momentum acceptance. * Y.Alexahin, E.Gianfelice-Wendt, A.Netepenko, Proc. IPAC10, Kyoto, May 2010, p. 1563

TUPPC042	Effect of Field Errors in Muon Collider IR Magnets on Beam Dynamics	multipole, 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.

TUPPC057	RHIC Spin Flipper Commissioning Results	resonance, polarization, injection, proton	1302
	M. Bai, W.C. Dawson, J. Kewisch, Y. Makdisi, P. Oddo, C. Pai, P.H. Pile, T. Roser BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The five ac dipole design of RHIC spin flipper in the Blue ring was first commissioned during the RHIC 2012 polarized proton operation. The advantage of this design is to eliminate the vertical coherent betatron oscillations outside the spin flipper. Spin flipping efficiency was measured with both 100 GeV and 250 GeV polarized proton beams. This paper presents the latest commissioning results. M. Bai , T. Roser, C. Dawson, Y. Makdisi, W. Meng, F. Meot, P. Oddo, C. Pai, P. Pile, RHIC Spin Flipper New Design and Commissioning Plan, IPAC10 proceedings, IPAC 2010, Kyoto, Japan, 2010

TUPPC058	Beam Energy Variation with Dipole Fault	sextupole, 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.

TUPPC059	Extraction of the Lie Map from Realistic 3D Magnetic Field Map	quadrupole, extraction, dynamic-aperture, lattice	1308
	Y. Li BNL, Upton, Long Island, New York, USA X. Huang SLAC, Menlo Park, California, USA
	Funding: Supported by Department of Energy Contract No. DE-AC02-98CH10886. We present a method to extract the Lie map of any arbitrary accelerator magnet from its actual 3D field map. After fitting a Taylor map from multi-particle tracking trajectories through the actual field, we factorize the map into a Lie map using Dragt-Finn's method. This method is validated by comparing with COSY-infinity for a soft-edge quadrupole model. Applications of extracting symplectic maps for the SPEAR and NSLS-II dipoles are shown as examples. A comparison of the map-tracking results against the direct field-integration-based method also is given.

TUPPC062	Transfer of Polarized 3He Ions in the AtR Beam Transfer Line	injection, ion, extraction, proton	1317
	N. Tsoupas, W.W. MacKay, F. Méot, T. Roser, D. Trbojevic BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US Department of Energy In addition to collisions of electrons with various unpolarized ion species as well as polarized protons, the proposed electron-hadron collider (eRHIC) will also facilitate the collisions of electrons with polarized 3He ions. The AGS is the last acceleration stage of ions before injection into one RHIC for final acceleration. The AtR (AGS to RHIC) transfer line will be utilized to transport the polarized 3He ions from AGS into one of the RHIC’s collider rings. In this paper we investigate the extraction energy of the polarized 3He ions from the AGS which will optimize the polarization of 3He ions injected into RHIC. Some of the peculiarities (interleaved horizontal and vertical bends) of the AtR line's layout may degrade this spin matching of the polarized 3He ions. We will also discuss possible simple modifications of the AtR line to accomplish a perfect “spin matching” of the injected 3He beam with that of the stable spin direction at the injection point of the RHIC ring.

TUPPC067	How to Achieve Longitudinally Polarized Electrons using Integer Spin Tune Resonances	polarization, resonance, synchrotron, electron	1326
	O. Boldt, A. Dieckmann, F. Frommberger, W. Hillert, J.F. Schmidt ELSA, Bonn, Germany
	Funding: Bundesministerium für Bildung und Forschung Commonly, strong solenoids are used in circular accelerators to achieve longitudinal polarization. In practice, however, these solenoids cause a phase space coupling, which has to be compensated for by sophisticated decoupling schemes. We suggest to adiabatically ramp into an integer spin tune resonance, while preserving the degree of polarization. When appropriately adjusting the driving horizontal field contributions at the final energy, the resulting polarization is longitudinal at predefined positions in the accelerator. Here, depending on the energy spread, the degree of polarization is conserved for several seconds. The contribution shows the numerical analysis of this scenario being confirmed by first demonstration tests at the ELSA stretcher ring.

TUPPC072	Modeling of Matching Channel for Accelerator Complexes	controls, lattice, booster, quadrupole	1338
	E.A. Podzyvalov, S.N. Andrianov St. Petersburg State University, St. Petersburg, Russia D. Zyuzin FZJ, Jülich, Germany
	Practically modern accelerator facility can be considered as a composite machines. Therefore it is necessary to consider special matching channels to joint all accelerator components together. For such channels advance various requirements, which can be formulated in the form of criteria sets. In this paper considered a global optimization concept allows to find appropriate solutions sets. This approach is demonstrated on the problem of modeling the matching channels for NICA accelerator complex.

TUPPC079	Tracking LHC Models with Thick Lens Quadrupoles: Results and Comparisons with the Standard Thin Lens Tracking	quadrupole, lattice, simulation, optics	1356
	M. Giovannozzi, H. Burkhardt, T. Risselada CERN, Geneva, Switzerland
	So far, the massive numerical simulation studies of the LHC dynamic aperture were performed using thin lens models of the machine. This approach has the clear advantage of speed, but it has also the disadvantage of requiring re-matching of the optics from the real thick configuration to the thin one. Furthermore, as the figure-of-merit for the re-matching is the agreement between the beta-functions for the two model, while the quadrupole gradients are left free parameters, the effect of the magnetic multipoles might be affected by this approach and in turn the dynamic aperture computation. In this paper the new approach is described and the results for the dynamic aperture are compared with the old approach, including detailed considerations on the CPU-time requirements.

TUPPC098	Electron Polarization in the Medium-Energy Electron-Ion Collider at JLAB	polarization, electron, solenoid, closed-orbit	1386
	F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang JLAB, Newport News, Virginia, USA D.P. Barber DESY, Hamburg, Germany
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A key feature of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is high polarization (over 80%) of the electron beam at all collision points for the particle physics program. The equilibrium electron polarization is arranged to be vertical in the arcs of the figure-8 collider ring of the MEIC and anti-parallel to the arc dipole magnetic fields, in order to take advantage of the preservation of polarization by the Sokolov-Ternov (S-T) effect. Longitudinal polarization is achieved at collision points by utilizing energy-independent universal spin rotators each of which consists of a set of solenoids and dipoles placed at the end of an arc. The equilibrium beam polarization and its lifetime depend on competition between the S-T effect and radiative depolarization. The latter must be suppressed by spin matching. This paper reports on investigations of polarization in the MEIC electron collider ring and a preliminary estimate of beam polarization from calculations using the code SLICK. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

TUPPD008	Recent Progress Toward a Muon Recirculating Linear Accelerator	linac, cryomodule, quadrupole, factory	1422
	K.B. Beard Muons, Inc, Batavia, USA M. Aslaninejad, C. Bonţoiu, A. Kurup, J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom S.A. Bogacz, V.S. Morozov, Y. Roblin JLAB, Newport News, Virginia, USA
	Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchrotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadrupoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.

TUPPD012	Complete Muon Cooling Channel Design and Simulations	emittance, simulation, solenoid, collider	1431
	C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson Muons, Inc, Batavia, USA Y.S. Derbenev, V.S. Morozov JLAB, Newport News, Virginia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD020	An EMMA Racetrack	quadrupole, injection, extraction, electron	1452
	B.D. Muratori, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.L. Owen UMAN, Manchester, United Kingdom
	EMMA (Electron Machine for Many Applications) is the world’s first prototype non-scaling electron FFAG hosted at Daresbury Laboratory. Several upgrade possibilities for EMMA are explored, from creating a dispersion-free region in the ring to facilitate injection and extraction to making an insertion in EMMA by turning it into a racetrack-style machine. Alternative methods of injection and extraction into the EMMA ring are explored together with their feasibility and implications. The option of developing nested racetracks to achieve a particular desired energy is also explored.

TUPPD033	Conceptual Design of a Positron-annihilation System for Generation of Quasi-monochromatic Gamma Rays	positron, target, photon, electron	1476
	R.J. Abrams, C.M. Ankenbrandt, K.B. Beard, G. Flanagan, R.P. Johnson, C. Y. Yoshikawa Muons, Inc, Batavia, USA A. Afanasev GWU, Washington, USA
	A conceptual design is presented for a system consisting of the following: an electron accelerator and production target to produce positrons, a dipole magnet and wedge to compress the positron momenta to be nearly monochromatic, a magnetic transport system to focus and direct the positrons to a converter, and a converter in which the positrons annihilate in flight to produce quasi-monochromatic gamma rays. The system represented is designed to produce ~10 MeV gammas, but it can also be designed for other energies.

TUPPD068	Design of the Production and Measurement of Ultra-Short Electron Bunches from an S-band RF Photoinjector	cavity, gun, electron, laser	1560
	J.W. McKenzie, D. Angal-Kalinin, J.K. Jones, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The Electron Beam Test Facility (EBTF) is planned for installation in late 2012 at Daresbury Laboratory. An S-band RF photoinjector provides ultrashort, low emittance electron bunches up to 6 MeV. A suite of diagnostics has been designed to fully characterise the bunches. A particular focus has been on producing and measuring bunch lengths less than 100 fs. This can be achieved with a multi-cell standing wave S-band transverse deflecting cavity. Operating such a cavity with low energy electrons provides certain challenges which are discussed in this paper with respect to beam dynamic simulations.

TUPPP003	Status and Very First Commissioning of the ASTRID2 Synchrotron Light Source	cavity, septum, vacuum, synchrotron	1605
	S.P. Møller, N. Hertel, J.S. Nielsen ISA, Aarhus, Denmark
	ASTRID2 is the new 10 nm UV and soft x-ray light source currently being built at Aarhus University, to replace the ageing source ASTRID. ASTRID2 is now in the end of its installation phase, with commissioning expected to take place during the spring. The status of the installation together with the first results of the commissioning will be presented.

TUPPP007	Modifications to the Machine Optics of BESSY II Necessitated by the EMIL Project	undulator, optics, cryogenics, storage-ring	1614
	P.O. Schmid, J. Bahrdt, T. Birke, R. Follath, P. Kuske, D. Simmering, G. Wüstefeld HZB, Berlin, Germany
	The Helmholtz Zentrum Berlin and the Max Planck Society are going to build a new dedicated X-ray beam line at the synchrotron source light source BESSY II which will be used for analyzing materials for renewable energy generation. The new large scale project has been dubbed EMIL. In this document we present the modifications to the machine optics and to what extent these changes affect the performance of BESSY II.

TUPPP017	Lattice Design of the SSRF Storage Ring with Superbend	lattice, emittance, photon, optics	1644
	S.Q. Tian, B.C. Jiang, H.H. Li, M.Z. Zhang, W.Z. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	The SSRF storage ring is being investigated by upgrading with normal conducting superbend of 3 T. The bending magnets are shortened, and thus some additional straight sections with the length of about 2 m are created in the center of the arc cell. They can be used to install more insertion devices. The lattice adjustment and the optics design are presented in this paper, where much efforts are made to maintain the effective emittance along the ring with respect to the nominal optics.

TUPPP019	Overview of the Solaris Facility	linac, storage-ring, klystron, vacuum	1650
	C.J. Bocchetta, M. Bartosik, P.P. Goryl, K. Królas, M. Młynarczyk, W. Soroka, M.J. Stankiewicz, P.S. Tracz, Ł. Walczak, A.I. Wawrzyniak, K. Wawrzyniak, J.J. Wiechecki, M. Zając, L. Zytniak Solaris, Kraków, Poland R. Nietubyć The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland
	Funding: Work supported by the European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09 The Polish synchrotron light source Solaris is under construction in Kraków. The project is based on the MAX IV light source being built in Lund, Sweden. The 1.5 GeV storage ring for Solaris and part of the injector complex are identical to that of MAX IV, although both are housed in buildings that differ from those of MAX IV. Ground breaking on the green field site at the Jagiellonian University campus occurred at the start of 2012. A detail description of the facility infrastructure, services and construction choices is given together with the latest project developments for main accelerator systems.

TUPPP024	Recent Progress on the MAX IV 1.5 GeV Storage Ring Lattice and Optics	storage-ring, lattice, vacuum, sextupole	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.

TUPPP065	Progress Report on the SwissFEL Injector Test Facility	emittance, quadrupole, laser, optics	1747
	T. Schietinger, M. Aiba, S. Bettoni, B. Beutner, M. Csatari, K. Doshekenov, Y.-C. Du, M.W. Guetg, C.P. Hauri, R. Ischebeck, F. Le Pimpec, N. Milas, G.L. Orlandi, M. Pedrozzi, P. Peier, E. Prat, S. Reiche, B. Smit, A. Trisorio, C. Vicario Paul Scherrer Institut, Villigen, Switzerland
	The SwissFEL injector test facility at the Paul Scherrer Institute is the principal test bed and demonstration plant for the SwissFEL project, which aims at realizing a hard-X-ray Free Electron Laser by 2017. The RF photoinjector facility has been in operation since 2010 and has recently reached its design energy of 250 MeV. A newly installed movable magnetic chicane allows longitudinal bunch compression studies. We report on the first experience with the bunch compressor and present the latest results of projected and slice emittance measurements.
	Poster TUPPP065 [1.801 MB]

TUPPP076	Soft Orbit Bumps for Duke Storage Ring VUV FEL Operation	FEL, radiation, wiggler, electron	1774
	S.F. Mikhailov, J.Y. Li, V. Popov, P.W. Wallace, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	Funding: This work is supported in part by the US DoE grant # DE-FG02-97ER41033. The Duke FEL and High Intensity Gamma-ray Source (HIGS) facility is operated with an electron beam from 0.24 to 1.2 GeV and a photon beam from 190 to 1060 nm. The current range of the gamma-beam energy is from 1 MeV to about 100 MeV, with the maximum total gamma-flux of more then 10¹⁰ gammas per second around 10 MeV. Production of the high intensity, high energy gamma-beams of 60-100 MeV using UV-VUV mirrors of 240 - 190 nm requires and high energy, high current electron beams of 0.9-1.05 GeV. The radiation damage problem becomes more severe for VUV FEL operation below 190 nm. The radiation from the End-of-Arc (EOA) bending magnets, instead of the radiation from FEL wigglers, is the dominant cause of a rapid degradation of the downstream FEL mirror. In this work, we propose a number of measures to significantly reduce the radiation from these dipole magnets as well as other potential sources of synchrotron radiation toward the FEL mirror. In particular, we describe the development of an orbit bump using designated "soft" orbit correctors. The magnetic field of these correctors is limited to produce a radiation with a critical wavelength close or below the FEL wavelength.

TUPPR006	Design Progress and Construction Status of SuperKEKB	quadrupole, status, wiggler, klystron	1822
	H. Koiso, K. Akai, K. Oide KEK, Ibaraki, Japan
	KEKB operation finished in June 2010, and the upgrade of KEKB to SuperKEKB has commenced. The design luminosity of SuperKEKB is 8×10³⁵cm^-2s^-1, which is 40 times higher than that of KEKB. The design strategy for SuperKEKB is based on the Nano-Beam Scheme, where the vertical beam sizes of the low-energy positron ring and the high-energy electron ring are squeezed to 50−60 nm at the interaction point with a large Piwinski angle. The beam currents in both rings will be double those in KEKB. Finalizing the design of the interaction region is going on by using precise modeling of beam optics. Dismantling KEKB rings and fabrication of accelerator components for SuperKEKB including magnets, power supplies, and antechamber-type beam pipes have already started. This paper describes design progress and construction status of SuperKEKB.

TUPPR008	One 233 km Tunnel for Three Rings: e⁺e^-, p-pbar, and μ⁺+μ⁻	collider, emittance, luminosity, lattice	1828
	G.T. Lyons, L.M. Cremaldi, A. Datta, M. Duraisamy, T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA
	Funding: Supported by DE-FG05-91ER40622 In 2001, a cost analysis was conducted to build a 233 km circumference tunnel in northern Illinois for a Very Large Hadron Collider (VLHC). Here we outline the implementations of e⁺e⁻, proton anti-proton, and μ⁺+ μ⁻ collider rings in such a tunnel using recent technological innovations. The 500 GeV e⁺e⁻ collider employs a Crab Waist Crossing, ultra low emittance damped bunches, a vertical IP focal length of 0.06 cm, 12 GV of superconducting RF, and 0.026 Tesla low coercivity, grain oriented silicon steel/concrete dipoles. The 40 TeV proton anti-proton collider uses the high intensity Fermilab anti-proton source, exploits high cross sections for proton anti-proton production of high mass states, and uses 2 Tesla 0.005% ultra low carbon steel/YBCO superconductor magnets run with liquid neon. The 40 TeV muon ring ramps the 2 Tesla superconducting magnets at 8 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 2 to 20 TeV in 72 orbits with 72% survival, and mitigates neutrino radiation with a phase shifting, roller coaster FODO lattice.* * G. T. Lyons, http://arxiv.org/pdf/1112.1105

TUPPR015	Choke-Mode Damped Structure Design for the CLIC Main Linac	wakefield, damping, simulation, impedance	1840
	H. Zha, H. Chen, W.-H. Huang, C.-X. Tang TUB, Beijing, People's Republic of China A. Grudiev, J. Shi, W. Wuensch CERN, Geneva, Switzerland
	Choke-mode damped accelerating structures are being studied as an alternative to the CLIC waveguide damped baseline structure. Choke-mode structures hold the potential for much lower pulsed surface heating and reduced cost since no milling is required. We propose a new choke geometry which has significant suppression of higher order dipoles. By impedance matching and detuning of the first dipole pass-band, the wakefield suppression is comparable to the baseline design with waveguide damping. A fully featured choke mode structure with the same accelerating gradient profile and filling time as the nominal CLIC design has been designed. It has the potential to replace the waveguide damped design without changing any of the machine layout or the beam parameters.

TUPPR027	Study of Multipolar RF Kicks from the Main Deflecting Mode in Compact Crab Cavities for LHC	cavity, multipole, 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.

TUPPR037	Simulations of Higher Order Modes in the ACC39 Module of FLASH	cavity, HOM, higher-order-mode, simulation	1900
	I.R.R. Shinton, R.M. Jones, P. Zhang UMAN, Manchester, United Kingdom Z. Li SLAC, Menlo Park, California, USA
	This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39 currently installed and in operation at FLASH and due to be installed at XFEL . Coupled inter-cavity modes are simulated together with a limited band of trapped modes. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. In this way the nature of the multi-cavity nature of these modules is investigated with implications for a HOM-based BPM system and direct comparison to experimental results.

TUPPR056	Parametric Study of the CLIC Damping Rings Delay Ring for Reaching Isochronicity Conditions	sextupole, 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.

TUPPR069	Calculation of Wakefields in 17-GHz Beam-Driven Photonic Bandgap Accelerator Structure	wakefield, simulation, damping, electron	1981
	M. Hu, B.J. Munroe, M.A. Shapiro, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA
	We present computer simulations of the wakefields in a six cell Photonic Bandgap (PBG) structure at 17GHz. Using the commercial code CST Particle Studio, the major accelerating mode (TM01) and dipole mode (TM11) are identified. The modes are excited by passing an 18MeV electron beam through the structure. The comparisons of the wakefields in an elliptical-rod PBG structure, round-rod PBG structure, and disc-loaded waveguide structure are carried out to verify experimental results. Various parameters, such as the beam charge and position, are varied to analyze the amplitude and decay time of the wakefields in the three structures. All of the simulation results will guide the design of next generation high gradient accelerator PBG structures.

TUPPR075	Challenges for the Magnet System of LHeC	electron, quadrupole, proton, linac	1996
	S. Russenschuck, B.J. Holzer, G. Kirby, A. Milanese, R. Tomás, D. Tommasini, F. Zimmermann CERN, Geneva, Switzerland
	The main challenges for the normal conducting magnet system are the very compact, low field, and high precision magnets for the ring-ring option and their rapid installation in the crowded LHC tunnel. The superconducting triplet magnets require strong gradients for the protons in close vicinity of a field-free region for the electrons. The field requirements for the ring-ring option allow a number of different magnet designs using the well-proven Nb-Ti superconductor technology and making use of the cable development for the LHC. The separation distance between the electron and proton beams in Q1 requires a half-aperture quadrupole design to limit the overall synchrotron radiation power emitted by the bending of the electron beam. The requirements in terms of aperture and field gradient are more difficult to obtain for the Linac-Ring option. Consequently we present the limitations for the field gradient and septum size achievable with both Nb-Ti and Nb3Sn superconducting technologies.

TUPPR076	The LHeC Project Development Beyond 2012	electron, linac, collider, cavity	1999
	F. Zimmermann, O.S. Brüning CERN, Geneva, Switzerland M. Klein The University of Liverpool, Liverpool, United Kingdom
	The LHeC study group is finalizing a Conceptual Design Report for publication early in 2012. This paper discusses the next steps required for developing a Technical Design Report and highlights the R&D developments, test facilities and implementation studies that need to be addressed over the coming years. Particular emphasize will be given to similarities with other ongoing accelerator and detector studies, and to a discussion of possible international collaboration efforts.

TUPPR080	Integration of Detector into Interaction Region at MEIC	ion, solenoid, optics, electron	2011
	V.S. Morozov, R. Ent, P. Nadel-Turonski JLAB, Newport News, Virginia, USA C. Hyde Old Dominion University, Norfolk, Virginia, USA
	Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The Jefferson Lab's Medium-energy Electron Ion Collider (MEIC) is proposed as a next-generation facility for the study of strong interaction (QCD). Accessing the relevant physics requires a full-acceptance detector with a dedicated small-angle high-resolution detection system capable of covering a wide range of momenta (and charge-to-mass ratios) with respect to the original ion beam. We present a design of such a detection system integrated into the collider's interaction region, in which full acceptance is attained by letting small-angle collision products pass through the nearest elements of the machine final-focusing system for further detection. The proposed design is consistent with the current collider optics and demonstrates an excellent performance in terms of detector acceptance and resolution. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

TUPPR085	Recycler Chromaticities and End Shims for NOvA at Fermilab	lattice, sextupole, quadrupole, dynamic-aperture	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.

WEYA02	Studies at CesrTA of Electron-Cloud-Induced Beam Dynamics for Future Damping Rings	electron, simulation, emittance, damping	2081
	G. Dugan, M.G. Billing, K.R. Butler, J.A. Crittenden, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, K.G. Sonnad, H.A. Williams CLASSE, Ithaca, New York, USA R.F. Campbell, R. Holtzapple, M. Randazzo CalPoly, San Luis Obispo, California, USA J.Y. Chu CMU, Pittsburgh, Pennsylvania, USA J.W. Flanagan, K. Ohmi KEK, Ibaraki, Japan M.A. Furman, M. Venturini LBNL, Berkeley, California, USA M.T.F. Pivi SLAC, Menlo Park, California, USA
	Funding: US National Science Foundation PHY-0734867, PHY-1002467, and PHY-1068662; US Dept. of Energy DE-FC02-08ER41538; and the Japan/US Cooperation Program. Electron clouds can adversely affect the performance of accelerators, and are of particular concern for the design of future low emittance damping rings. Studies of the impact of electron clouds on the dynamics of bunch trains in CESR have been a major focus of the CESR Test Accelerator program. In this paper, we report measurements of coherent tune shifts, emittance growth, and coherent instabilities carried out using a variety of bunch currents, train configurations, beam energies, and transverse emittances, similar to the design values for the ILC damping rings. We also compare the measurements with simulations which model the effects of electron clouds on beam dynamics, to extract simulation model parameters and to quantify the validity of the simulation codes.
	Slides WEYA02 [2.033 MB]

WEOBA01	Construction Progress of the RHIC Electron Lenses	electron, solenoid, gun, proton	2125
	W. Fischer, Z. Altinbas, M. Anerella, E.N. Beebe, M. Blaskiewicz, D. Bruno, W.C. Dawson, D.M. Gassner, X. Gu, R.C. Gupta, K. Hamdi, J. Hock, L.T. Hoff, A.K. Jain, R.F. Lambiase, Y. Luo, M. Mapes, A. Marone, T.A. Miller, M.G. Minty, C. Montag, M. Okamura, A.I. Pikin, S.R. Plate, D. Raparia, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, P. Wanderer, S.M. White, W. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. In polarized proton operation, the RHIC performance is limited by the head-on beam-beam effect. To overcome these limitations two electron lenses are under construction. We give an overview of the progress over the last year. Guns, collectors and the warm electron beam transport solenoids with their associated power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of gun, collector and some of the instrumentation. The RHIC infrastructure is being prepared for installation, and simulations continue to optimize the performance.
	Slides WEOBA01 [7.672 MB]

WEOBA02	Tevatron End-of-Run Beam Physics Experiments	antiproton, proton, emittance, luminosity	2128
	A. Valishev Fermilab, Batavia, USA X. Gu, R. Miyamoto, S.M. White BNL, Upton, Long Island, New York, USA J. Qiang LBNL, Berkeley, California, USA F. Schmidt CERN, Geneva, Switzerland
	Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP). Before the Tevatron collider Run II ended in September of 2011, a two-week period was devoted to the experiments on various aspects of beam-beam interactions. The studied topics included offset collisions, coherent beam stability, effect of the bunch-length-to-beta-function ratio, and operation of AC dipole with colliding beams. In this report we summarize the results of beam experiments and supporting simulations.
	Slides WEOBA02 [1.382 MB]

WEEPPB010	RF Modeling Using Parallel Codes ACE3P for the 400-MHz Parallel-Bar/Ridged-Waveguide Compact Crab Cavity for the LHC HiLumi Upgrade	damping, cavity, HOM, impedance	2185
	Z. Li, L. Ge SLAC, Menlo Park, California, USA J.R. Delayen, S.D. Silva ODU, Norfolk, Virginia, USA
	Funding: Work partially supported by the US DOE through the US LHC Accelerator Research Program (LARP), and by US DOE under contract number DE-AC02-76SF00515. Schemes utilizing crab cavities to achieve head-on beam-beam collisions were proposed for the LHC HiLumi upgrade. These crabbing schemes require that the crab cavities be compact in order to fit into the tight spacing available in the existing LHC beamlines at the location where the crab cavities will be installed. Under the support of US LARP program, Old Dominion University and SLAC have joint efforts to develop a 400-MHz compact superconducting crab cavity to meet the HiLumi upgrade requirements. In this paper, we will present the RF modeling and analysis of a parallel-bar/ridged-waveguide shaped 400-MHz compact cavity design that can be used for both the horizontal and vertical crabbing schemes. We will also present schemes for HOM damping and multipacting analysis for such a design.

WEEPPB013	Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR	quadrupole, octupole, background, multipole	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.

WEEPPB014	The Magnetic Model of the LHC during the 3.5 TeV Run	quadrupole, injection, controls, optics	2194
	E. Todesco, N. Aquilina, M. Giovannozzi, M. Lamont, F. Schmidt, R.J. Steinhagen, M. Strzelczyk, R. Tomás CERN, Geneva, Switzerland N.J. Sammut University of Malta, Information and Communication Technology, Msida, Malta
	The magnetic model of the LHC is based on a fit of the magnetic measurements through equations that model the field components (geometric, saturation, persistent) at different currents. In this paper we will review the main results related to the magnetic model during the run of the LHC in 2010-2011: with a top energy of 3.5 TeV, all components of the model but the saturation are visible. We first give an estimate of the reproducibility of the main components and multipolar errors as they can be deduced from beam measurements, i.e. orbit, tune, chromaticity, beta beating and coupling. We then review the main results relative to the decay at injection plateau, dependence on powering history, and snapback at the beginning of the ramp for both tune and chromaticity. We discuss the precision obtained in tracking the magnets during the ramp, where the persistent current components gradually disappear. We conclude by presenting the behaviour of the quadrupoles model during the squeeze. A list of the major changes implemented during the operation together with what are considered as the main open issues is given.

WEPPC053	SSR1 HOM Analysis and Measurements	HOM, quadrupole, cavity, higher-order-mode	2333
	M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE Single spoke resonators (SSR1, β=0.22) are currently under development for Project X at Fermilab. In this paper, extensive Higher Order Mode (HOM) analysis carried out on SSR1 is reported including the simulated R/Q for monopoles, dipoles, and quadrupoles. HOM measurements carried out on several spoke cavities are also reported including the harmonic response and the bead pull measurements. Comparison between the measured R/Q values and the simulated ones are presented.

WEPPC086	Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cyromodule	cavity, damping, HOM, impedance	2414
	L. Xiao, Z. Li, C.-K. Ng SLAC, Menlo Park, California, USA A. Nassiri, G.J. Waldschmidt, G. Wu ANL, Argonne, USA R.A. Rimmer, H. Wang JLAB, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A single-cell superconducting deflecting cavity operating at 2.812 GHz has been proposed and designed for the Short Pulse X-ray (SPX) project for the Advanced Photon Source upgrade. A cryomodule of 4 such cavities will be needed to produce the required 2-MV deflecting voltage. Each deflecting cavity is equipped with one fundamental power coupler (FPC), one lower order mode (LOM) coupler, and two higher order mode (HOM) couplers to achieve the stringent damping requirements for the unwanted modes. The damping of the HOM/LOM modes below the beampipe cutoff has been analyzed in the single cavity geometry and shown to meet the design requirements. The HOMs above beam pipe cutoff in the 4-cavity cyromodule, however, may result in cross coupling which may affect the HOM damping and potentially trapped modes between the cavities which could produce RF heating to the beamline bellows and even be detrimental to the beam. We have evaluated the HOM damping and trapped modes in the 4-cavity cryomodule using the parallel finite element EM code ACE3P developed at SLAC. We will present the results of the cryomodule analysis in this paper.

WEPPC087	Second Harmonic Cavity Design for Project-X Main Injector	cavity, simulation, HOM, impedance	2417
	L. Xiao, C.-K. Ng SLAC, Menlo Park, California, USA J.E. Dey, I. Kourbanis Fermilab, Batavia, USA
	In order to accelerate the proposed beam intensity for Project-X, a new RF system for Main Injector (MI) will be required. A new 53 MHz first harmonic RF cavity that meets the MI requirements for Project-X has been designed. In order to reduce the peak longitudinal beam density a 10⁶ MHz second harmonic RF system is also needed. The first harmonic RF cavity design is a quarter wave coaxial resonator with a single accelerating gap and a perpendicular biased ferrite tuner. The second harmonic RF cavity baseline design is similar to the fundamental one and scaled down from it. RF simulations and shape optimizations on the second harmonic cavity are carried out to obtain the optimal performance which meets Project-X requirements. The results are discussed and presented in this paper.

WEPPD011	Study of the Pressure Profile Inside the NEG Coated Chambers of the SIS 18	vacuum, simulation, quadrupole, ion	2519
	M.C. Bellachioma, H. Kollmus, A. Krämer, J. Kurdal, H. Reich-Sprenger, L. Urban, M. Wengenroth GSI, Darmstadt, Germany
	In the context of the technical developments for the construction of FAIR at GSI, an intensive programme for the vacuum upgrade of the existing SIS 18 was started in 2005, with the aim to improve the beam lifetime and intensity. To reach these purposes also the installation of NEG coated dipole and quadrupole chambers is foreseen. During the upgrade shutdowns performed between 2006 and 2009 the vacuum chambers of approximately 65% of the SIS18 circumference were replaced by NEG coated pipes. To evaluate in detail the pressure profile inside the coated chambers mounted into the accelerator a dedicated experimental set-up, which reproduces a vacuum environment similar to the one of the SIS 18, was built. Using three gauges, mounted in different positions of a coated chamber, it was possible to measure the pressure in the range of 10^-12 mbar inside the activated NEG pipe and 10^-11 mbar outside the pipe at the pumping posts. Additionally, a modelling of a SIS18 vacuum sector was realised and the pressure variation values obtained by a Monte-Carlo simulation were compared with those measured. In this paper the experimental results and the vacuum simulations are described and discussed.

WEPPD043	The Studies of Power System Harmonics at TLS	coupling, power-supply, cryogenics, controls	2609
	T.-S. Ueng, J.-C. Chang, Y.F. Chiu, K.C. Kuo, Y.-C. Lin NSRRC, Hsinchu, Taiwan
	The power system harmonic distortion in the utility system of NSRRC is investigated for improving the power system performance. The monitored power quality data at the point of common coupling is examined and compared with industrial standards. In addition, the harmonic characteristics of electric power for the accelerator magnets and adjustable speed drives which contribute the most harmonics are analyzed. Furthermore, the approach to mitigate the harmonic effects for improving the power quality is studied.

WEPPD079	Measurements of Magnetic Permeability of Soft Steel at High Frequencies	impedance, booster, vacuum, damping	2711
	Y. Tokpanov, V.A. Lebedev, W. Pellico Fermilab, Batavia, USA
	The Fermilab Booster does not have a vacuum chamber which would screen the beam from laminations its dipoles cores. Therefore the booster impedance is mainly driven by the impedance of these dipoles. Recently an analytical model of the laminated dipole impedances was developed. However to match the impedance measurements with calculations one needs an accurate measurement of soft steel magnetic permeability. This paper presents the measurement results of the permeability in a frequency range from ~10 MHz to 1 GHz. Measurements of e.-m. wave propagation in 30 cm long strip line built from soft steel were used to compute the permeability. Measurements were performed in a DC magnetic field to observe the effect of steel saturation on the high frequency permeability. Both real and imaginary parts of the permeability were measured. As expected their values were decreasing with frequency increase from 10 MHz to 1 GHz and with saturation of steel DC permeability. Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.

WEPPD081	Optimization of AC Dipole Parameters for the Mu2e Extinction System	proton, emittance, magnet-design, electron	2714
	E. Prebys Fermilab, Batavia, USA
	The Mu2e experiment is being planned at Fermilab to measure the rate for muons to convert to electrons in the field of an atomic nucleus with unprecedented precision. This experiment uses an 8 GeV primary proton beam consisting of short (~200 nsec FW) bunches, separated by 1.7 μs. It is vital that out-of-bunch beam be suppressed at the level of 10^-10 or less. This poster describes the parametric analysis which was done to determine the optimum harmonics and magnet specifications for this system, as well as the implications for the beam line optics.

WEPPD084	The E-Lens Test Bench for Rhic Beam-Beam Compensation	electron, gun, controls, cathode	2720
	X. Gu, Z. Altinbas, J.N. Aronson, E.N. Beebe, W. Fischer, D.M. Gassner, K. Hamdi, J. Hock, L.T. Hoff, P. Kankiya, R.F. Lambiase, Y. Luo, M. Mapes, J.-L. Mi, T.A. Miller, C. Montag, S. Nemesure, M. Okamura, R.H. Olsen, A.I. Pikin, D. Raparia, P.J. Rosas, J. Sandberg, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, W. Zhang 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. To compensate for the beam-beam effects from the proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are fabricating two electron lenses that we plan to install at RHIC IR10. Before installing the e-lenses, we are setting-up the e-lens test bench to test the electron gun, collector, GS1 coil, modulator, partial control system, some instrumentation, and the application software. Some e-lens power supplies, the electronics for current measurement will also be qualified on test bench. The test bench also was designed for measuring the properties of the cathode and the profile of the beam. In this paper, we introduce the layout and elements of the e-lens test bench; and we discuss its present status towards the end of this paper.

WEPPP004	A Reciprocity Principle for Wakefields in a Two-Channel Coaxial Dielectric Structure	wakefield, vacuum, simulation, acceleration	2726
	G.V. Sotnikov NSC/KIPT, Kharkov, Ukraine J.L. Hirshfield, T.C. Marshall, G.V. Sotnikov Omega-P, Inc., New Haven, USA S.V. Shchelkunov Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
	Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics. The reciprocity principle* is often used in applications of classical electromagnetism. We have employed this principle for testing wakefields set up by an electron bunch in a two-channel coaxial dielectric structure (CDWA)*. For numerical studies we take a ~1-THz fused silica structure which we plan to test at FACET/SLAC; it has dimensions: outer shell, OD=800 μm, ID=500 μm; inner shell OD=181 μm, ID=50 μm. The structure is energized by a 23-GeV, 3-nC bunch having axial RMS size=25 μm. FACET has no drive bunch of annular shape as required for a CDWA; nevertheless, our analytical studies and simulations prove that for the axial wakefield, an annular drive bunch can be replaced by a pencil-like bunch of the same charge traveling in the annular vacuum channel. The longitudinal electric field along the accelerator channel axis (as recorded by a witness bunch) set up by this pencil-like bunch is the same as in the conventional structure of the CDWA. Moreover, if we interchange the drive bunch and the witness bunch, the witness bunch will register the same axial wakefield. However, the stability of the annular bunch is far superior to that of the pencil bunch. L. D. Landau and E. M. Lifshitz, Electrodynamics of Continuous Media (Addison-Wesley: Reading, MA, 1960). **G. Sotnikov et al., PRST-AB, 061302 (2009).

WEPPP020	Rebunching Low Energy Neutrons by Magnetic Acceleration and Deceleration	neutron, acceleration, controls, focusing	2766
	Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Arimoto, H.M. Shimizu KEK, Ibaraki, Japan P.W. Geltenbort ILL, Grenoble, France S. Imajo Kyoto University, Kyoto, Japan M. Kitaguchi Kyoto University, Research Reactor Institute, Osaka, Japan Y. Seki RIKEN Nishina Center, Wako, Japan T. Yoshioka Kyushu University, Fukuoka, Japan
	Funding: Supported by the Grant-in-Aid for Creative Scientific Research of MEXT under the Program 19GS0210, the Quantum Beam Fundamentals Development Program of the MEXT, and KEK Neutron Program 2009S03. Ultra cold neutrons (UCN) - neutrons with energies less than 300 neV - can be accelerated or decelerated by means of static magnetic and RF fields. The method and experimental setup will be described in detail and the results of a recent first test experiment will be presented. The detail cannot be disclosed until the paper is published.

WEPPP042	Experimental Demonstration of Wakefield Effects in a 250 GHz Planar Diamond Accelerating Structure	wakefield, radiation, acceleration, electron	2816
	S.P. Antipov, J.E. Butler, C.-J. Jing, A. Kanareykin, P. Schoessow, S.S. Zuo Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York, USA W. Gai ANL, Argonne, USA
	Funding: DOE SBIR We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism. Fields produced by a first, drive, beam were used to accelerate a second, witness, electron bunch which followed the driving bunch at an adjustable distance. The energy gain of the witness bunch as a function of its separation from the drive bunch is a direct measurement of the wake potential. We also present wakefield mapping results for THz quartz structures. In this case decelerating wake inside the bunch is inferred from the drive beam energy modulation.

WEPPP061	A Method to Obtain the Frequency of the Longitudinal Dipole Oscillation for Modeling and Control in Synchrotrons with Single or Double Harmonic RF Systems	synchrotron, controls, ion, emittance	2846
	J. Grieser, J. Adamy, D.E.M. Lens TU Darmstadt, RTR, Darmstadt, Germany H. Klingbeil TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This work was partly funded by GSI Helmholtzzentrum für Schwerionenforschung GmbH In a heavy-ion synchrotron the bunched beam can perform longitudinal oscillations around the synchronous particle (single bunch dipole oscillation, SBDO). If disturbances/instabilities exciting the SBDO exceed the rate of Landau damping, the beam can become unstable. Furthermore, Landau damping is accompanied by an increase of the beam emittance which may be undesired. Thus, control efforts are taken to stabilize the beam and to keep the emittance small. It is known that for a single harmonic cavity and a small bunch the SBDO oscillates with the synchrotron frequency* if the oscillation amplitudes are small. For a larger bunch or a double harmonic RF systems that introduces nonlinearities*, this is no longer valid. This work shows how the frequency of the SBDO can be determined in general. As a result, the SBDO can again be modeled as a harmonic oscillator with an additional damping term to account for Landau damping. This model can be used for feedback designs which is shown by means of a simple example. As the frequency of the SBDO and the damping rate depend on the size of the bunch in phase space, it is shown how this information can be obtained from the measured beam current. F. Pedersen and F. Sacherer, IEEE Transactions on Nuclear Science, 24:1296–1398, 1977 ** A. Hofmann and S. Myers, Proc. of the 11th International Conference on High Energy Acceleration, 1980

WEPPP064	Design and Simulation of the Stripline Transverse Quadrupole Kicker for HLS II	quadrupole, kicker, impedance, storage-ring	2852
	F.F. Wu, W.B. Li, P. Lu, T.J. Ma, B.G. Sun, Y.Y. Xiao, H. Xu, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	In order to investigate the possibility of excite a transverse quadrupole mode oscillation of the electron bunch in the HLS II storage ring, we design a stripline transverse quadrupole kicker. The characteristic impedance of some modes(dipole modes, sum mode, quadrupole mode) of the optimised stripline kicker must match 50Ω characteristic impedance of the external transmission lines so as to reduce the reflected power. We use nonlinear least square method to optimise the kicker and compare characteristic impedances of calculation using 2D Possion code and fitted function of several variables, then we get optimised size with integrated use of Possion code and fitted function of several variables. Using the 2D Poisson code, we simulate the electric field distribution of dipole modes when the horizontal or the vertical electrodes are at opposite unit potentials, and the electric field distribution of quadrupole mode using quadrupole kick. We verified that the designed stripline kicker can excite a transverse quadrupole mode oscillation of the electron bunch.

WEPPP070	Simulation of the APS Storage Ring Orbit Real-Time Feedback System Upgrade Using MATLAB	feedback, storage-ring, simulation, controls	2870
	S. Xu, G. Decker, R.I. Farnsworth, F. Lenkszus, H. Shang, X. Sun 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. The Advanced Photon Source (APS) storage ring orbit real-time feedback (RTFB) system plays an important role in stabilizing the orbit of the stored beam. An upgrade is planned that will improve beam stability by increasing the correction bandwidth to 200 Hz or higher. To achieve this, the number of available steering correctors and beam position monitors (BPMs) will be increased, and the sample rate will be increased by an order of magnitude. An additional benefit will be the replacement of aging components. Simulations have been performed to quantify the effects of different system configurations on performance.

WEPPP083	Near Real-time Response Matrix Calibration for 10-Hz GOFB	feedback, damping, injection, quadrupole	2903
	C. Liu, R.L. Hulsart, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The 10-Hz global orbit feedback, for damping the trajectory perturbation (~10 Hz) due to the vibrations of the triplets, is operational for injection and store in RHIC. The operation of the system has been performed using transfer functions between the beam position monitors and correctors obtained from the online optics model and a correction algorithm based on singular value decomposition (SVD). Calibration of the transfer functions by measuring the beam position oscillations while modulating the dedicated correctors has been carried out. The feedback results with model matrix and measured matrix will be compared.

WEPPR027	Complete Electromagnetic Design of the ESS-Bilbao RFQ Cold Model	rfq, quadrupole, simulation, radio-frequency	2991
	A. Vélez, I. Bustinduy, J. Feuchtwanger, N. Garmendia, O. González, I. Madariaga, J.L. Muñoz, D. de Cos ESS Bilbao, Bilbao, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain V. Etxebarria, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	In this work, the ESS-Bilbao 352,2 Mhz RFQ Cold Model to be built in the ESS-Bilbao accelerator facility is presented. The Cold Model intends to be a small scale representation of the final 4 meters long RFQ which will be able to accelerate a 75 mA proton beam from 75 keV to 3 MeV. The work shown here covers the complete electromagnetic design process of the Cold Model which will be built in aluminium with a total length of 1 meter. Moreover, in order to find out fabrication tolerances, a longitudinal test modulation in the vane regions similar to the one designed for the final RFQ is included in the Cold Model. This modulation represents also a useful tool in order to test the agreement between measurements and electromagnetic simulations. In addition, a complete parametric study of the RFQ ends and radial matchers is presented as an important design parameter able to adjust the field flatness. Finally, slug tuning rods are also added to be able to test the tuning procedures. A final RFQ Cold Model prototype has been designed and is currently under fabrication.

WEPPR033	Performance of Low-Energy Magnetic Bunch Compression for the ASTA Photoinjector at Fermilab	simulation, emittance, cryomodule, collective-effects	3006
	C.R. Prokop, P. Piot Northern Illinois University, DeKalb, Illinois, USA B.E. Carlsten LANL, Los Alamos, New Mexico, USA M.D. Church Fermilab, Batavia, USA
	Funding: LANL LDRD program, project 20110067DR -U.S. DOE Contract No. DE-FG02-08ER41532 and DE-AC02-07CH11359. The Advanced Superconducting Test Accelerator (ASTA) at Fermilab incorporates a magnetic bunch compressor chicane to compress the 40-MeV electron bunches generated in the photoinjector. In this paper, we present a numerical analysis and parametric study of the bunch compressor's performance for various operating scenarios. The beam dynamics simulations, carried out with Astra, Impact-Z and CSRTrack, are compared against each other. Finally, an operating regime with low phase space dilutions is suggested based on the simulation results.

WEPPR047	The Effect of Non-Zero Closed Orbit on Electron-Cloud Pinch Dynamics	electron, quadrupole, proton, simulation	3033
	G. Franchetti GSI, Darmstadt, Germany F. Zimmermann CERN, Geneva, Switzerland
	A study on the pinch dynamics of electron cloud during a bunch passage under the effect of a single arbitrary-order multipole was presented at IPAC2011. The complexity of the pinch pattern is directly related to the order of the multipolar field. However, in a realistic situation, the proton beam will not be located in the center of the vacuum chamber. If the beam is offset a new pinch regime is encountered, where feed-down effects and asymmetry of pinch density render the dynamics more challenging. In this paper we discuss the pinch dynamics with orbit offset, including the resulting orbit variation along a bunch, and address their relevance for the incoherent effect of the electron cloud.

WEPPR051	Issues for a Multi-bunch Operation with SPARC C-band Cavities	wakefield, HOM, linac, betatron	3042
	A. Mostacci, M. Migliorati, L. Palumbo URLS, Rome, Italy D. Alesini, B. Spataro, C. Vaccarezza INFN/LNF, Frascati (Roma), Italy
	SPARC C-band traveling wave cavities were originally designed for the SPARC energy upgrade in the single bunch operation mode. In the context of a gamma source based on Compton backscattering and based on the SPARC C-band technology, we investigated the issues related to the use of these structures in the multi-bunch operation mode. Several beam configurations have been considered and the effects of transverse and longitudinal long range wakefields on beam dynamics have been studied. In the paper we present the results of these studies and, in particular, the issues related to transverse beam break-up that could prevent the multi-bunch operation. Possible HOM damped structures are also proposed.

WEPPR056	Reproduction of Ceramic Chamber Impedances with Electric and Magnetic Polarities of the Ceramics	impedance, vacuum, synchrotron, proton	3051
	Y. Shobuda, M. Kinsho JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In proton synchrotron, ceramic chambers are used as vacuum chambers to avoid the effect on magnetic fields from eddy current excited by the magnetic fields. One of the standard methods of the derivation of the impedances of the ceramic chamber is the field matching technique. In this report, we reproduce the formulae of the ceramic chamber impedance in terms of electric and magnetic polarities. When the beam passes through the chamber, the impedance is mainly excited by the electric polarity of the ceramic.

WEPPR060	Short range wakefields in MAX IV and FERMI Linac	wakefield, linac, cavity, electron	3063
	O. Karlberg, F. Curbis, S. Thorin, S. Werin MAX-lab, Lund, Sweden P. Craievich, E. Ferrari, G. Penco ELETTRA, Basovizza, Italy
	Ultra-short electron pulses suffer from transverse wake fields resulting in a degradation of the beam quality. Since transverse emittance is a crucial parameter for possible FEL drivers, a careful characterization of wakefields is necessary in the design and commissioning phase of a high-brightness linear accelerator. In this paper we investigate the effect of short-range transverse wakefields in the MAXIV linac in various compression modes. Estimations of the wake potentials have been done with 3D modeling of the accelerating structures as well as with analytical models.

WEPPR066	Effects of the External Wakefield from the CLIC PETS	linac, wakefield, luminosity, emittance	3078
	A. Latina, D. Schulte CERN, Geneva, Switzerland J. Gao, Y. Wang IHEP, Beijing, People's Republic of China
	The CLIC main linac accelerating structures will be powered by the Power Extraction and Transfer Structure (PETS) located in the drive beam decelerators. Misalignments of the PETS will excite dipolar modes in the couplers of the main linac structures that will kick the beam leading to beam quality degradation. In this paper, the impact of such dipolar kicks is studied, and tolerances, based on analytical estimations, are found both in the single- and the multi-bunch regimes. Numerical simulation obtained using the tracking code PLACET are shown to confirm the analytical estimates.

WEPPR075	Monitoring the Progress of LHC Electron-Cloud Scrubbing by Benchmarking Simulations and Pressure-Rise Observations	electron, simulation, vacuum, injection	3105
	C.O. Domínguez, G. Arduini, E. Métral, G. Rumolo, F. Zimmermann CERN, Geneva, Switzerland G. Iadarola Naples University Federico II, Science and Technology Pole, Napoli, Italy
	Electron bombardment of a surface has been proven to reduce drastically the secondary electron yield of a material. This technique, known as scrubbing, is the ultimate solution to decrease the negative effects of an electron cloud build-up in any particle accelerator operating with intense beams. Its effectiveness has been already observed at the LHC. Since at the LHC no in-situ secondary-yield measurements are available, it has been necessary to develop a method to infer different key beam-pipe surface parameters by benchmarking simulations and pressure-rise observations. The method developed allows us to monitor the scrubbing process in order to decide on the most appropriate strategies for machine operation. In this paper we present the latest results of applying this method to the LHC in the fall of 2011 and early 2012, including data for the nominal bunch spacing of 25 ns.

WEPPR088	Modeling and Simulation of Retarding Field Analyzers at CESRTA	electron, simulation, vacuum, gun	3138
	J.R. Calvey, J.A. Crittenden, G. Dugan, W. Hartung, J. Makita, M.A. Palmer CLASSE, Ithaca, New York, USA M.A. Furman, M. Venturini LBNL, Berkeley, California, USA
	Funding: Work supported by the US National Science Foundation (PHY-0734867 and PHY-1002467), and Department of Energy (DE-FC02-08ER41538). Over the course of the CESRTA program at Cornell, Retarding Field Analyzers (RFAs) have been installed in drift, dipole, quadrupole, and wiggler field regions of the CESR storage ring. RFAs are used to measure the local electron cloud flux on the vacuum chamber wall. Through the use of a retarding grid and segmented collectors, they also provide information on the energy and transverse distribution of the cloud. Understanding these measurements on a quantitative level requires the use of cloud buildup simulation codes, adapted to include a detailed model of the structure of the RFA and its interaction with the cloud. The nature of this interaction depends strongly on the strength of the local magnetic field. We have developed models for RFAs in drift and dipole regions. The drift model has been cross-checked with bench measurements, and we have compared the RFA-adapted cloud buildup simulations with data. These comparisons have then been used to obtain best fit values for the photo-emission and secondary electron emission characteristics of some of the vacuum chamber materials and cloud mitigating coatings employed at CESRTA.

THYA01	High Field Magnet Developments	quadrupole, luminosity, alignment, collider	3185
	T. Nakamoto KEK, Ibaraki, Japan
	Superconducting magnets for future accelerators need to generate a field beyond 10 T. However, mature NbTi superconductors which have been already operated at its performance limit at LHC cannot be adopted. Instead, A15 type superconductors have been considered to be promising materials for the high field magnets. Especially, intensive R&D efforts for the LHC luminosity upgrade with state-of-the-art Nb3Sn superconductors have been carried out. Further future accelerators such as the High-Energy LHC and muon accelerators must require the high field reaching 20 T or more. This means that utilization of HTS (high Tc superconductors) would be the only possible solution. However, it is known that these advanced superconductors are not mechanically robust in comparison with the practical NbTi and the performance is influenced by mechanical stress and strain. In addition, magnetization effects caused by larger effective filament diameters may compromise the field quality in the accelerators. The magnet developments to overcome these issues are ongoing. This presentation will try to review the US and worldwide high field accelerator magnet developments: achievements, status, and plans.
	Slides THYA01 [7.578 MB]

THXB03	Beam and Spin Dynamics in an Electric Proton EDM Ring	proton, lattice, storage-ring, quadrupole	3203
	R.M. Talman CLASSE, Ithaca, New York, USA J. Talman BNL, Upton, Long Island, New York, USA
	Electric dipole moment (EDM) measurements may help to answer the question ‘‘Why is there more matter than anti-matter in the present universe?'' For a charged baryon like the proton such a measurement is thinkable only in a ring in which a bunch of protons is stored for more than a few minutes, with polarization ‘‘frozen'' (relative to the beam velocity) and with polarization not attenuated by decoherence. Beam and spin dynamics in an all-electric lattice with these characteristics is described. Rings for other charged baryons, such as deuterons or helium-3 nuclei, are also possible but, requiring both electric and magnetic fields, they are more complicated.
	Slides THXB03 [0.155 MB]

THEPPB006	Improving the Synchrotron Performance of the Heidelberg Ionbeam Therapy Center	ion, synchrotron, controls, extraction	3243
	Th. Haberer HIT, Heidelberg, Germany
	The HIT linac-synchrotron-system routinely delivers pencil beams to the dose delivering rasterscanning devices at 3 treatment rooms, including the worldwide first scanning ion gantry, and 1 experimental cave. At HIT the quality-assured library of pencil beam parameters covers roughly 100.000 combinations of the ion, energy, intensity and beam size. Each patient-specific treatment plan defines a subset of these pencil beams being subsequently requested during the dose delivery. Aiming at shortened irradiation times an upgrade program making heavy use of feed-back mechanisms is under way. Driven by patient-specific data out of the scanning beam dose delivery process central synchrotron components are coupled to the therapy control system in order to tailor the beam characteristics in real-time to the clinical requirements. The paper will discuss the functional upgrades and report about the impact on the medical application at HIT.

THPPC015	Design of a Four-vane 325 MHz RFQ Cold Model at Tsinghua University	rfq, cavity, resonance, simulation	3308
	L. Du, J.C. Cai, X. Guan, Q.Z. Xing TUB, Beijing, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (Project 11175096). The design of a Radio Frequency Quadrupole (RFQ) accelerator cold model at Tsinghua University is presented in this paper. The 1-meter-long aluminium cold model is chosen to be the same as the low-energy part of the 3-meter-long RFQ for the Compact Pulsed Hadron Source (CPHS) project at Tsinghua University. This cold model will be used mainly for the RFQ field study and education. It will work at the RF frequency of 325 MHz. All the simulations are finished by the SUPERFISH and MAFIA codes.

THPPC020	Accurate Measurement of Ferrite Garnets to be used for Fast-tuned Ferrite Loaded Cavities in the Range of 20-40 MHz	cavity, impedance, resonance, vacuum	3317
	C. Vollinger, F. Caspers CERN, Geneva, Switzerland
	For the implementation of ferrite-tuned cavities with perpendicular biased ferrites in the frequency range of 20 to 40 MHz, different types of ferrite garnets were evaluated in terms of their electromagnetic properties. We describe a precision measurement method applicable to small-sized ferrite samples of 1-square-inch surface and 2 mm thickness in the given frequency range. During measurement, these samples are exposed to varying magnetic bias fields of different orientations. Two different techniques for the determination of the real and the imaginary part of the permeability are required to achieve sufficiently accurate results. We present a detailed description of these methods as well as results obtained.

THPPC022	Enhanced Coupling Design of a Detuned Damped Structure for CLIC	wakefield, coupling, damping, simulation	3323
	A. D'Elia, A. Grudiev, V.F. Khan, W. Wuensch CERN, Geneva, Switzerland T. Higo KEK, Ibaraki, Japan R.M. Jones UMAN, Manchester, United Kingdom
	The key feature of the improved coupling design in the Damped Detuned Structure (DDS) is focused on the four manifolds. Rectangular geometry slots and rectangular manifolds are used. This results in a significantly stronger coupling to the manifolds compared to the previous design. We describe the new design together with its wakefield damping properties.

THPPD007	ILSF Storage Ring Magnets	quadrupole, sextupole, 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.

THPPD008	Status of the PAL-XFEL Undulator System	undulator, controls, FEL, status	3509
	D.E. Kim, H.S. Han, Y.-G. Jung, H.-G. Lee, W.W. Lee, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea J. Pflüger European XFEL GmbH, Hamburg, Germany
	Funding: Work supported by POSCO and MEST of Korea. Pohang Accelerator Laboratory (PAL) is developing 10 GeV, 0.1 nm SASE based FEL for high power, short pulse X-ray coherent photon sources named PAL-XFEL. At the first stage PAL-XFEL needs two undulator lines for photon source. PAL is developing undulator magnetic structure based on EU-XFEL design. The hard Xray undulator features 7.2 mm min magnetic gap, and 5.0 m magnetic length with maximum effective magnetic field larger than 0.908 T to achieve 0.1nm radiation at 10 GeV electron energy. In this report, we discuss the status of the hard X-ray undulator and soft X-ray undulator designs.

THPPD009	Accelerator Magnets R&D Programme at CERN	quadrupole, permanent-magnet, linac, luminosity	3512
	D. Tommasini, L. Bottura, G. De Rijk, L. Rossi CERN, Geneva, Switzerland
	The exploitation and evolution of the CERN accelerator complex pose a continuous challenge for magnet engineers. Superconducting and resistive magnets have a comparable share. The overall mass of either is approximately 50,000 tons, spread over 3 major machines (PS, SPS and LHC), two large experimental area, and a number of smaller experiments and accelerator rings. On the short term (2012-2014) the CERN plan is to upgrade its injection chain (Linac4) and experimental area (HIE-Isolde, ELENA) that require mostly a multitude of resistive magnets. The medium-term plan for the evolution of the LHC complex (2015-2021), also referred to as High-Luminosity LHC, foresees interventions on about 1 km of the machine, with magnets to be substituted with higher field, larger aperture, or both. On the long term (2025-2035) we are exploring the technological challenges of very high field magnets, at the verge of 20 T for a High Energy LHC (HE-LHC), or extremely stable high gradient quadrupoles for the Compact Linear Collider (CLIC). In this paper we provide an overview of the R&D activities addressing the various lines of development, the technology milestones, and a broad time schedule.

THPPD015	Character and Performance of Magnets for the TPS Storage Ring	sextupole, multipole, quadrupole, 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.

THPPD017	Mu2e AC Dipole 300 kHz and 5.1 MHz Tests and Comparison of Nickel-Zinc Ferrites	pick-up, proton, impedance, target	3533
	L. Elementi, K.R. Bourkland, D.J. Harding, V.S. Kashikhin, A.V. Makarov, H. Pfeffer, G. Velev Fermilab, Batavia, USA
	To suppress any background events coming from the inter-bunch proton interactions during the muon transport and decay window for the Mu2e experiment, a beam extinction scheme based on two dipoles running at ~300 kHz and 5.1 MHz is considered. The effective field of these magnets is synchronized to the proton bunch spacing in such a way that the bunches are transported at the sinus nodes. Two types Ni-Zn ferrites are considered for these dipoles. Ferrites, their characteristics and ferrites selection is herein discussed through measurements performed under conditions close to operational. The excitation system and the measurement of some characteristics of the magnetic field and field shape and measurement mechanism are also presented.

THPPD018	Precision Magnet Measurements for X-band Accelerator Quadrupole Triplets	quadrupole, alignment, emittance, controls	3536
	R.A. Marsh, S.G. Anderson, J.P. Armstrong LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

THPPD020	Test of a 1.8 Tesla, 400 Hz Dipole for a Muon Synchrotron	power-supply, simulation, synchrotron, acceleration	3542
	D.J. Summers, L.M. Cremaldi, T.L. Hart, L.P. Perera, M. Reep UMiss, University, Mississippi, USA S.U. Hansen, M.L. Lopes Fermilab, Batavia, USA J. Reidy Oxford High School, Mississippi, USA H. Witte BNL, Upton, Long Island, New York, USA
	Funding: Supported by DE-FG05-91ER40622. A 1.8 Tesla dipole magnet using 0.011" AK Steel TRAN-COR H-1 grain oriented silicon steel laminations has been constructed as a prototype for a muon synchrotron ramping at 400 Hz. Following the practice in large 3 phase transformers and our own OPERA-2D simulations, joints are mitered to take advantage of the magnetic properties of the steel which are most effective in the direction in which the steel was rolled. Measurements with a Hysteresigraph 5500 and Epstein Frame show a high magnetic permeability which minimizes stored energy in the yoke so the magnet can ramp quickly with modest voltage. A power supply with a fast IGBT switch and a polypropylene capacitor was constructed. Coils are wound with 12 gauge copper wire which will eventually be cooled with with water flowing in stainless steel tubes. The magnetic field was measured with an F. W. Bell 5180 peak sensing Hall Probe connected to a Tektronics TDS3054B oscilloscope.

THPPD021	SC Magnet Development for SIS100 at FAIR	quadrupole, sextupole, 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.

THPPD025	Expected and Measured Behaviour of the Tune in the LHC Operation at 3.5 TeV	injection, quadrupole, feedback, betatron	3554
	N. Aquilina CERN, Geneva, Switzerland
	The tune of the Large Hadron Collider depends on the strength of the quadrupole magnets, the b2 component in the main dipoles plus the b3 component in the main dipoles and the sextupolar correctors via feed down in case of systematic misalignment. The magnetic model of the machine, based on a fit of magnetic measurements, has an intrinsic precision which can be estimated in a few units. During the first years of operation of the LHC, tune has been routinely measured and corrected through a feedback system. In this paper we reconstruct from the beam measurements and the settings of the feedback loop the evolution of tune during injection, ramp, and squeeze. This gives the obtained precision of the magnetic model of the machine with respect to quadrupolar and sextupolar components. At the injection plateau there is an unexpected large decay whose origin is not understood: we present the data, with the time constants and the dependence on the previous cycles, and compare to the magnetic measurements. During the ramp the tune drifts by about 0.05: this precision is related to the precision in tracking the quadrupolar field in the machine.

THPPD026	Splice Resistance Measurements in the LHC Main Superconducting Magnet Circuits by the New Quench Protection System	monitoring, background, injection, controls	3557

Paper

Title

Other Keywords

Page

MOXBP01

The First Two Years of LHC Operation

luminosity, proton, ion, emittance

1

S. Myers
CERN, Geneva, Switzerland

The operational performance of the LHC machine both for proton and lead ion operation are reviewed for the period 2010 and up the present. The beam parameter path allowing the very high rate of collider performance is presented and discussed. The accelerator issues encountered and those somewhat surprisingly not encountered are also discussed. The short and longer term plans for the LHC are also briefly presented.

Slides MOXBP01 [17.468 MB]

MOEPPB004

A Compact Ring Design with Tunable Momentum Compaction

damping, dynamic-aperture, quadrupole, emittance

82

Y. Sun
SLAC, Menlo Park, California, USA

A storage ring with tunable momentum compaction has the advantage in achieving diﬀerent RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre- damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and ﬁne tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

MOEPPB014

Time Jitter Measurements in Presence of a Magnetic Chicane in the FERMI@elettra Linac

electron, linac, FEL, laser

109

G. Penco, P. Craievich, S. Di Mitri, M.M. Milloch, F. Rossi
ELETTRA, Basovizza, Italy

Accurate and highly stable temporal synchronization between an electron bunch and a pulse from an external seed laser is one of the key requirements for successful operation of a seeded FEL in the XUV and soft x-ray regime. These requirements become more stringent when the electron bunch is longitudinally compressed to sub-ps durations in order to increase the current for more efficient FEL action. In this paper we present experimental measurements of the electron bunch arrival time jitter after the first magnetic compressor of FERMI@Elettra seeded FEL as a function of the compression factor. The experimental behavior of the pulse-to-pulse time jitter agrees both with results from tracking code simulations and with predictions from an analytical approach that takes into account the different sources of time jitter in FERMI, namely the photoinjector drive laser, the RF accelerating cavity phases and voltages, and fluctuations in the chicane bending magnet currents. We also present predictions for the expected arrival time jitter in the final configuration of FERMI that includes two bunch compressors and for which the synchronization requirement is of order 100 fs or better.

MOPPC001

Simulation of electron-cloud heat load for the cold arcs of the large hadron collider

electron, simulation, injection, photon

115

G.H.I. Maury Cuna
CINVESTAV, Mérida, Mexico
G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy
G. Rumolo, F. Zimmermann
CERN, Geneva, Switzerland

The heat load due to the electron cloud in the Large Hadron Collider (LHC) cold arcs is a concern for its performance near and beyond nominal beam current. We report the results of simulation studies, which examine the electron-cloud induced heat load for different values of low-energy electron reflectivity and secondary emission yield at injection energy, as well as at beam energies of 4 TeV and 7 TeV, for two different bunch spacing: 25 ns and 50 ns. Benchmarking the simulations against heat-load observations at different beam energies and bunch spacing allows an estimate of the secondary emission yield in the cold arcs of the LHC and of its evolution as a function of time.

MOPPC009

Multipactor for E-cloud Diagnostics

electron, resonance, cyclotron, vacuum

139

P. Costa Pinto, F. Caspers, P. Edwards, M. Holz, M. Taborelli
CERN, Geneva, Switzerland

Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed though a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic field. Preliminary result show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the event of a large scale coating production this technique will be a valuable resource for quality control.

MOPPC016

Combined Ramp and Squeeze at the Large Hadron Collider

optics, injection, quadrupole, collider

157

S. Redaelli, M. Lamont, G.J. Müller, R. Tomás, J. Wenninger
CERN, Geneva, Switzerland
N. Ryckx
EPFL, Lausanne, Switzerland

In the first two years of operation of the CERN Large Hadron Collider (LHC), the betatron squeeze has been carried out at constant flat top energy of 3.5 TeV. Squeeze setting functions are separated from the energy ramp functions. This ensured a maximum flexibility during commissioning because stopping at all intermediate optics for detailed measurements was possible. In order to then improve the efficiency of the operational cycle, combining the ramp and squeeze has been considered. In this paper, the various possibilities for this scheme are reviewed, and proposals of optimized operational cycles with combined ramp and squeeze are presented for different energies. Results of beam tests are also discussed.

MOPPC028

Coherent Beam-Beam Effects Observation and Mitigation at the RHIC Collider

emittance, simulation, damping, coupling

193

S.M. White, M. Bai, W. Fischer, Y. Luo, A. Marusic, M.G. Minty
BNL, Upton, Long Island, New York, USA

Funding: Work partially supported by Brookhaven Science Associates, LARP, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

MOPPC032

Injection and Broadband Matching for the PRISM Muon FFAG

injection, betatron, solenoid, target

202

J. Pasternak, R. Chudzinski, A. Kurup
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
A. Sato
Osaka University, Osaka, Japan

The next generation of lepton flavor violation experiments requires high intensity and high quality muon beams. Such conditions can be met using phase rotation of short muon pulses in an FFAG ring, as was proposed for the PRISM project. The very large initial momentum spread and transverse emittance of the muon beam poses a significant challenge for the injection system into the PRISM FFAG. Also, the matching optics between the solenoidal transfer channel and the ring needs to create a specific orbit excursion in the horizontal plane, suppress any vertical dispersion and produce good betatron conditions in both planes. Candidate geometries for the matching and injection systems are presented and their performances are tested in tracking studies.

MOPPC042

Higgs Boson Muon Collider Factory: h⁰, A, H Studies

collider, factory, solenoid, simulation

226

D.B. Cline, X.P. Ding, J.L. Lederman
UCLA, Los Angeles, California, USA

With the recent hints of the Higgs boson from the LHC and a mass near 125 GeV/c we re-propose to study and build a muon collider Higgs factory to study the Higgs in the S channel. This was first proposed in 1992 by the first author. It is essential to study the Higgs boson for clues to new physics. The formation of the DOE MAP program, recent advances in 6D μ cooling methods, simulation, and targeting make this a feasible project to initiate at this time. This collider would fit into the FNAL site.

MOPPC043

Injection/Extraction of Achromat-based 6D Ionization Cooling Rings for Muons

injection, solenoid, kicker, extraction

229

X.P. Ding, D.B. Cline
UCLA, Los Angeles, California, USA
J.S. Berg, H.G. Kirk
BNL, Upton, Long Island, New York, USA
A.A. Garren, F.E. Mills
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: This work was supported in part by the US Department of Energy in part under award numbers DE-FG02-92ER40695 (UCLA), DE-AC02-98CH10886 (BNL) and DE-FG02-07ER84855 (Particle Beam Lasers, Inc.).
An achromat-based cooing ring using dipoles and solenoids is introduced and it can cool muons by large factors in six dimensions to achieve the necessary luminosity for a muon collider. The ring is designed with sufficient space in each superperiod for injection and extraction magnets. We estimate the parameters for the injection system into the solenoid-dipole ring cooler. We also present some simulations for injection/extraction system and discuss the injection/extraction requirements*.
* Al Garren, J.S. Berg, D. Cline, X. Ding, H.G. Kirk, “Robust 6D μ± cooling using a solenoid-dipole ring cooler for a muon collider”, NIM A 654 (2011) 40-44.

MOPPC045

Scaled Electron Model of a Dogbone Muon RLA with Multi-pass Arcs

linac, electron, quadrupole, optics

235

S.A. Bogacz, A. Hutton, G.A. Krafft, V.S. Morozov, Y. Roblin
JLAB, Newport News, Virginia, USA
K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by USDOE STTR Grant DE-FG02-08ER86351.
The design of a dogbone RLA with linear-field multi-pass arcs was earlier developed for accelerating muons for a future Neutrino Factory and Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over single pass or pulsed arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme in which a 4.35 MeV/c electron beam is injected in the middle of a 2.9 MeV/pass linac with two double-pass return arcs, and is accelerated to 17.4 MeV/c in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it feasible to utilize the existing technologies.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPPC053

Modeling of Bending Magnets for SIRIUS

simulation, multipole, 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

multipole, 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.

MOPPC063

Computation of the 2D Transverse Wake Function of an Electron Cloud for Different Parameters

electron, simulation, lattice, wakefield

280

A. Markoviḱ, G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Work supported by DFG under contract number RI 814/20-2.
A PIC simulation of the interaction of a positive charged bunch with an e-cloud yields the wake kick from the electrons on the tail particles of the bunch. The wake is induced from a certain offset in the transverse position of the head parts of the bunch which perturb the electron distribution. Such a pre-computed wake functions of each offset part of the bunch are forming a matrix which could be used for investigating single bunch stability under several assumptions. In this paper we investigate the linear scalability of the kick with the offset value. Furthermore we investigate the wake values for different realistic electron densities. Another important parameter for realizing the single bunch stability simulation is the optimal number of bunch slices in longitudinal direction. Here we study the thickness of the slices in conjunction with the mobility of the electrons around the beam axis.

MOPPC081

Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field

electron, cavity, simulation, site

325

G.V. Romanov, V.S. Kashikhin
Fermilab, Batavia, USA

In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low-Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of an RF cavity with beryllium windows in a solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to the RF electric field significantly modifies the performance of RF cavities. However, the magnetic field in a Helical Cooling Channel has a strong dipole component in addition to a solenoidal one. The dipole component essentially changes electron motion in a cavity compared to a pure solenoidal case, making dark current less focused at field emission sites. The simulation of a dark current dynamic in HCC performed with CST Studio Suite is presented in this paper.

MOPPD033

Strong-focusing Cyclotron - High-current Applications

cyclotron, proton, focusing, cavity

436

P.M. McIntyre, S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, J.N. Kellams, T.L. Mann, A.D. McInturff, N. Pogue, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: This work is supported by grants from the State of Texas (ASE) and from the Mitchell Family Foundation.
Quadrupole focusing channels are integrated into the pole faces of a superconducting sector cyclotron, to enable control of the betatron tunes for all orbits. This provision makes it possible to lock the tunes to desired values for all orbits, thereby eliminating resonance crossing and facilitating local orbit bumps for injection and extraction. Optical control is of particular importance for applications where higher beam current is desired, for ADS fission drivers, for spallation neutron sources, and for medical isotope production.

MOPPD041

Beam Loss Protection for a 2.3 Megawatt LBNE Proton Beam

quadrupole, proton, power-supply, target

454

R.M. Zwaska, S.C. Childress, A.I. Drozhdin, N.V. Mokhov, I.S. Tropin
Fermilab, Batavia, USA

Funding: U.S. Department of Energy.
Severe limits are required for allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6·10¹⁴ protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that localized loss of a single beam pulse at 2.3 MW will result in a destructive event: beam pipe failure, damaged magnets and high levels of residual radiation inside the tunnel. A sustained full beam loss would be catastrophic. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

MOPPD043

Novel Muon Beam Facilities for Project X at Fermilab

proton, target, linac, electron

457

C.M. Ankenbrandt, R.J. Abrams, T.J. Roberts, C. Y. Yoshikawa
Muons, Inc, Batavia, USA
D.V. Neuffer
Fermilab, Batavia, USA

Innovative muon beam concepts for intensity-frontier experiments such as muon-to-electron conversion are described. Elaborating upon a previous single-beam idea, we have developed a design concept for a system to generate four high quality, low-energy muon beams (two of each sign) from a single beam of protons. As a first step, the production of pions by 1 and 3 GeV protons from the proposed Project X linac at Fermilab is being simulated and compared with the 8-GeV results from the previous study.

MOPPD050

Dipole Magnet Design for a Bunch Compressor

neutron, linac, proton, focusing

478

T. Kanesue, L.P. Chau, O. Meusel, D. Noll, U. Ratzinger
IAP, Frankfurt am Main, Germany

The FRANZ-ARMADILLO is a Mobley type bunch compressor system at the pulsed intense neutron source FRANZ, under construction at Frankfurt University. The FRANZ-ARMADILLO compresses 9μbunches of a 150 mA, 2 MeV proton beam accelerated by a 175 MHz linac into one short pulse of 1 ns pulse length with 250 kHz repetition rate. In the bunch compressor, two homogeneous dipole magnets and two gradient dipole magnets guide theμbunches, separated by a 5 MHz RF-kicker on individual tracks. The flight path length of theμbunches are determined based on the bunch center velocity and the linac frequency for the longitudinal bunch compression. The gradient dipole magnets provide individual magnetic fields and edge focusing forces to everyμbunch. For the center trajectory, the required parameters are a magnetic field density of 509.2 mT, bending angle of 78.27 deg, and bending radius of 404.5 mm. To satisfy all specifications, field clamps, shims, and chamfer cut will be adopted. The result of the gradient dipole magnet design and the expected performance based on beam dynamics studies will be presented.

MOPPD057

CERN PSB-to-PS Transfer Modifications for the 2 GeV Upgrade

injection, optics, quadrupole, septum

493

W. Bartmann, J. Borburgh, S.S. Gilardoni, B. Goddard, A. Newborough, S. Pittet, R. Steerenberg
CERN, Geneva, Switzerland
C.H. Yu
IHEP, Beijing, People's Republic of China

Within the frame of the CERN PS Booster (PSB) energy upgrade from 1.4 to 2 GeV, the PSB to PS transfer line will be adapted for pulse-to-pulse modulated operation. A modified lattice is presented including a re-design of the switching dipole between ISOLDE and PS and additional collimators to protect the PS injection septum. Optics solutions optimized for small emittance LHC beams as well as for the large emittance high-intensity beams are shown.

MOPPD063

A 180 MeV Injection System for the ISIS Synchrotron

injection, synchrotron, electron, simulation

511

B. Jones, D.J. Adams, M.C. Hughes, S.J.S. Jago, H. V. Smith, C.M. Warsop, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It operates at 50 Hz accelerating 3x10¹³ protons per pulse via a 70 MeV H⁻ linac and an 800 MeV proton synchrotron, delivering a mean beam power of 0.2 MW. A favoured first step to upgrade ISIS towards the megawatt regime is replacement of the linac with a new 180 MeV injector. Studies of this upgrade, which aims to increase mean beam power up to 0.5 MW are continuing. This paper summarises designs for a new injection region including beam dynamics and related hardware.

MOPPD071

Error Localization in RHIC by Fitting Difference Orbit

storage-ring, feedback, closed-orbit, optics

526

C. Liu, M.G. Minty, V. Ptitsyn
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.
Many errors in an accelerator are evidenced as transverse kicks to the beam, which distort the beam trajectory. Therefore, the information of the errors are imprinted in the distorted orbits, which are different from what would be predicted by the optics model. In this paper, we introduce an algorithm for fitting the orbit based on an on-line optics model. We apply the algorithm to localize the location of the elusive source of vertical diurnal variations observed in RHIC, and analyze D0/Dx errors in local coupling measurement.

MOPPD084

Optimization of Extinction Efficiency in the 8-GeV Mu2e Beam Line

proton, target, background, alignment

565

I.L. Rakhno, A.I. Drozhdin, C. Johnstone, N.V. Mokhov, E. Prebys
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
A muon-to-electron conversion experiment at Fermilab is being designed to probe for new physics beyond the standard model at mass scales up to 10000 TeV*. The advance in experimental sensitivity is four orders of magnitude when compared to existing data on charged lepton flavor violation. The critical requirement of the experiment is the ability to deliver a proton beam contained in short 100-ns bunches onto a muon production target, with an inter-bunch separation of about 1700 ns. In order to insure the low level of background at the muon detector consistent with the required sensitivity, protons that reach the target between bunches must be suppressed by an enormous factor, 109. This paper describes the results of numerical modeling with STRUCT and MARS codes for a beam line with a collimation system**,*** and optics that achieves an experimental extinction factor of one per billion.
* R.M. Carey et al., Mu2e Proposal, Fermilab (2008).
** W. Molzon, “Proton Beam Extinction,” MECO-EXT-05-002 (2005).
*** E. Prebys, Mu2e-doc-534 (2009), http://mu2e-docdb.fnal.gov.

MOPPP013

Passive Momentum Spread Compensation by a “Wakefield Silencer”

wakefield, electron, simulation, FEL

598

S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, USA

Funding: DOE SBIR.
We report an observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 5 cm long dielectric loaded waveguide structure. The experiment was conducted at the ATF facility at BNL according to a concept dubbed a wakefield silencer originally developed at the ANL AATF*, which involves defining the electron bunch peak current distribution and selecting the optimal waveguide structure suitable for chirp cancellation using self-induced wakefields of the electron bunch. Our experiment has been carried out with a 247 micron triangular beam with a 200 keV energy spread, which was reduced by a factor of three to approximately 70 keV by passing it through a 0.95 THz dielectric-lined structure. Theoretical analysis supports the experimental results. Further exploration and applications of this technique will be discussed as well.
* M. Rosing, J. Simpson, Argonne Wakefield Accelerator Note, WF -144 (1990).

MOPPP033

Diagnostics at PITZ 2.0 Beamline: Status and New Developments

emittance, electron, diagnostics, FEL

634

M. Otevřel, A. Donat, H.-J. Grabosch, M. Groß, L. Hakobyan, H.M. Henschel, L. Jachmann, M. Khojoyan, G. Klemz, W. Köhler, G. Koss, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, H. Leich, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, J. Meissner, A. Oppelt, M. Penno, B. Petrosyan, M. Pohl, S. Riemann, M. Sachwitz, B. Schöneich, J. Schultze, A. Shapovalov, F. Stephan, F. Tonisch, G. Vashchenko, L.V. Vu, T. Walter, S. Weisse, R.W. Wenndorff, M. Winde
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
N.I. Brusova, L.V. Kravchuk, V.V. Paramonov
RAS/INR, Moscow, Russia
A. Gonnin, M. Joré, B. Mercier, C. Prevost, A. Variola
LAL, Orsay, France
I.I. Isaev
MEPhI, Moscow, Russia
Ye. Ivanisenko
IERT, Kharkov, Ukraine
D. Richter
HZB, Berlin, Germany
S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand
A.A. Zavadtsev, D.A. Zavadtsev
Nano, Moscow, Russia

The main aim of the Photo Injector Test Facility at DESY, Zeuthen (PITZ) site is to develop and test an FEL photo injector system capable of producing high charge short electron bunches of lowest possible transverse emittance to allow optimum FEL performance. The last major beamline upgrade realized in the second half of the year 2011 completed the evolution of the PITZ setup ongoing since 2005. The most recent upgrades include the installation of a new RF deflecting cavity - a prerequisite for longitudinal emittance and high resolution slice emittance measurements and installation of a new dispersive section for longitudinal phase space diagnostics of the high energy electron bunches. The paper will give an overview on electron beam diagnostics at PITZ, including the above mentioned upgrades.

MOPPP034

Simulation of the Longitudinal Phase Space Measurement with Transverse Deflecting Structure at PITZ

cavity, electron, emittance, simulation

637

D. Malyutin, M. Krasilnikov, M. Otevřel, F. Stephan
DESY Zeuthen, Zeuthen, Germany

The main goal of the Photo Injector Test facility at DESY, Zeuthen site, (PITZ) is the development, optimization and detailed characterization of electron sources for the short wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL. For successful operation of such type of FELs the injector must provide high quality electron bunches, enough short in duration with high charge and small transverse and longitudinal emittance values. Installation of the Transverse Deflecting Structure (TDS) at PITZ will provide the possibility for detailed characterization of bunch temporal profile, bunch transverse slice emittance and longitudinal phase space. The TDS cavity is currently installed at the PITZ beamline, and commissioning of the whole TDS system is expected in the spring 2012. In the first part of the paper the basic principles of the TDS deflector are described. In the next section, simulation of measurements by TDS cavity applied to the PITZ beam parameters is presented. The temporal resolution for different types of measurements is discussed. Systematic limitations are estimated.

MOPPP036

Progress in Reducing the Back-bombardment Effect in the ITC-RF gun for t-ACTS Project at Tohoku University

cathode, electron, gun, simulation

643

X. Li, H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, T. Muto, K. Nanbu, Y. Tanaka
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
F. Miyahara
KEK, Ibaraki, Japan

An ITC (independently tunable cells) thermionic RF gun* has been developed to produce sub-picosecond electron pulses as part of the injector for coherent terahertz radiation at Tohoku University. Both experiments and simulations have shown that the back-bombardment (B.B.) effect on the LaB6 cathode is a serious issue for option. A numerical model has been developed to evaluate the temperature increase of the cathode due to B.B. in which a 2D equation for heat conduction is solved by taking the back-streaming electrons into account. Using this model we have studied the possibility of suppressing the B.B. by employing dipole field and optimization of the cathode radius, compared with experimental data. Other methods and the prospect of the RF gun will also be reported.
* H. Hama et al., New J. Phys. 8 (2006) 292

MOPPP052

Booster Synchrotron for SIRIUS Light Source

booster, injection, extraction, emittance

679

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

A full energy 3 GeV booster for the new Brazilian Synchrotron Light Laboratory (LNLS) third generation light source, SIRIUS, is proposed. The 144 m circumference magnetic lattice consists of two super-periods of FODO cells with defocusing dipoles and focusing quadrupoles. The optics provides a low emittance beam of 38 nm.rad at 3 GeV, high horizontal betatron and zero dispersion functions at straight sections. The top-up operation requires a cycling energy ramp from 150 MeV to 3 GeV with repetition rate of 1 Hz.

MOPPP053

Failure Mode Analysis in Preparation for Top-up Injection at the Canadian Light Source (CLS)

injection, storage-ring, kicker, simulation

682

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

Top-up injection involves injecting beam with beamline safety shutters open. Consequently it is extremely important that no electrons enter the beamlines where they could be a potential safety hazard to beamline personnel. To investigate the likelihood that electrons could exit the storage ring various failure mode simulations have been done. The approach is to account for all possible injection trajectories and show that these particles will be intercepted by various storage ring apertures before they reach an amplitude that is deemed unsafe. This amplitude was chosen to be 50 mm and the field roll-off of all storage ring magnets were defined to this amplitude. Failure modes invested included injection kicker failures, uncorrected misalignment errors, off-energy injection and shorted storage ring magnet coils. Errors that would render it impossible to store beam were not investigated. As some particles reached amplitudes beyond the safe limit measures have been devised to eliminate these unsafe scenarios.

MOPPP060

Top-Off Mode of Operations: Setting Limits on the Extracted Beam Energy by Constraining Currents of Multiple Booster Dipole Power Supplies.

booster, extraction, lattice, injection

696

T.V. Shaftan
BNL, Upton, Long Island, New York, USA

In preparation for top-off mode of the NSLS-II operations we have studied impact of errors in the dipole power supply current on the extracted beam energy, which has to be interlocked so to satisfy the safety requirements. The NSLS-II booster dipole circuits are combined into 3 independent PS circuits, which adds complexity to the analysis of the extracted beam energy limits.

MOPPR057

Development of a Cavity Beam Position Monitor for CLIC

cavity, linac, coupling, factory

915

F.J. Cullinan, S.T. Boogert, N.Y. Joshi, A. Lyapin
JAI, Egham, Surrey, United Kingdom
E. Calvo, N. Chritin, F. Guillot-Vignot, T. Lefèvre, L. Søby
CERN, Geneva, Switzerland
A. Lunin, M. Wendt, V.P. Yakovlev
Fermilab, Batavia, USA
S.R. Smith
SLAC, Menlo Park, California, USA

The Compact Linear Collider (CLIC) project presents many challenges to its subsystems and the beam diagnostics in particular must perform beyond current limitations. The requirements for the CLIC main beam position monitors foresee a spacial resolution of 50 nm while delivering a 10 ns temporal resolution within the bunch train. We discuss the design of the microwave cavity pick-up and associated electronics, bench top tests with the first prototype cavity, as well as some of the machine-specific integration and operational issues.

MOPPR069

Use of Waveguide and Beam Pipe Probes as Beam Position and Tilt Monitoring Diagnostics with Superconducting Deflecting Cavities

cavity, HOM, monitoring, simulation

945

X. Sun, T.G. Berenc, G. Decker, G.J. Waldschmidt, G. Wu
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.
Waveguide and beam pipe field probes associated with a superconducting deflecting cavity are explored as beam position and tilt monitoring diagnostics. The superconducting deflecting cavity will be used for the Short-pulse X-rays (SPX) in the Advanced Photon Source (APS) upgrade project. Microwave Studio will be used to simulate the techniques of detecting the fields excited by the beam passing through the cavity and determining how close the beam is on electrical center.

MOPPR088

Cavity BPM for 1300 MHz Cryomodules

cavity, coupling, wakefield, cryomodule

993

N. Barov, D.J. Newsham, D. Wu
Far-Tech, Inc., San Diego, California, USA

Funding: Work supported by DOE grant DE-SC00004498
A cavity BPM for 1300 MHz cryomodules is under development by FAR-TECH, Inc. The BPM is capacitively loaded to fit in a small area, and uses a novel coupling scheme which further cuts down space requirements. We discuss status of the fabrication, and eventual plan to test the diagnostic at the ANL Wakefield Accelerator facility.

TUXB01

Progress Towards Ultimate Storage Ring Light Sources

emittance, brightness, electron, wiggler

1035

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.
Developments such as the low emittance NSLS-II storage ring, followed by the even lower emittance MAX-IV ring, demonstrate that the technology of storage ring light sources has not reached full maturity. Indeed, these new sources are paving the way toward realizing diffraction-limited angstrom-wavelength storage ring light sources in the not-too-distant future. Our discussion begins with a review of recent trends and developments in storage ring design. We then survey on-going work around the world to develop concepts and designs for so-called "ultimate" storage ring light sources.

Slides TUXB01 [3.442 MB]

TUOAC02

Development of HTS Magnets

superconductivity, resonance, synchrotron, neutron

1095

K. Hatanaka, M. Fukuda, N. Hamatani, N. Izumi, K. Kamakura, T. Saito, H. Ueda, Y. Yasuda, T. Yorita
RCNP, Osaka, Japan
T. Kawaguchi
KT Science Ltd., Akashi, Japan

A quarter of a century has passed since the discovery of high-temperature superconductor (HTS) materials in 1986. Although many prototype devices using HTS wires have been developed, these applications are presently rather limited in accelerator and beam line facilities. We have investigated the performance of HTS wires applied for magnets excited by alternating current (AC) as well as direct current (DC) for a decade. In order to check feasibilities of pulse magnets using HTS wire, we have fabricated a super-ferric dipole magnet to be operated by lumping currents. Upper and lower coil consists of 3 double pancakes of 200 turns. Critical currents were measured of wire measured at 77K. Self-field Ic of wire was higher than 160A. Ic values of double pancakes were 60-70A. After stacking, they were 47A and 51A for the upper and lower coil, respectively. Cooling tests were successfully done and the Ic values were measured to be 280A at 20K. Performance tests are ongoing in the pulse mode operation.

Slides TUOAC02 [5.252 MB]

TUOAC03

Status of a Single-Aperture 11 T Nb3Sn Demonstrator Dipole for LHC Upgrades

collimation, status, magnet-design, lattice

1098

A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, R. Bossert, G. Chlachidze, V. Kashikhin, A. Nobrega, I. Novitski, D. Turrioni, R. Yamada
Fermilab, Batavia, USA
B. Auchmann, M. Karppinen, L. Oberli, L. Rossi, D. Smekens
CERN, Geneva, Switzerland

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 includes two additional collimators to be installed in the dispersion suppressor areas of points 2, 3 and 7. The necessary longitudinal space for the collimators could be provided by replacing some 8.33 T NbTi LHC main dipoles with 11 T dipoles based on Nb3Sn superconductor and compatible with the LHC lattice and main systems. To demonstrate t his possibility Fermilab and CERN have started in 2011 a joint R&D program with the goal of building by 2014 a 5.5-m long twin-aperture dipole prototype suitable for installation in the LHC. 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 describes the design, construction and test results of the single-aperture Nb3Sn demonstrator model for the LHC collimation system upgrade.

Slides TUOAC03 [5.812 MB]

TUOBC03

Experimental Measurements of e-Cloud Mitigation using Clearing Electrodes in the DAΦNE Collider

positron, vacuum, wiggler, electron

1107

D. Alesini, T. Demma, A. Drago, A. Gallo, S. Guiducci, C. Milardi, P. Raimondi, M. Zobov
INFN/LNF, Frascati (Roma), Italy
S. De Santis
LBNL, Berkeley, California, USA

Recently the electron-positron collider DAΦNE has started delivering luminosity to the KLOE-2 experiment. For this run special metallic electrodes for e-cloud clearing were installed in all the dipole and wiggler magnets of the collider positron ring. Experimental measurements of the effectiveness of the electrodes in the mitigation of the e-cloud effects in the positron beam have been done showing an impressive effectiveness of these devices in the cure of the e-cloud effects in the positron beam. In particular the electrodes allow reducing the vertical beam size increase, the growth rate of transverse instabilities and the tune shifts induced by the electron cloud. Frequency shifts measurements of the vacuum chamber resonances switching on and off the electrodes have also been done showing their effect in the reduction of the electron cloud density. In this paper we summarize the results of all our observations and the experimental measurements of the e-cloud suppression with these electrodes.

Slides TUOBC03 [2.825 MB]

TUEPPB008

Status Report on the Iranian Light Source Facility Project

storage-ring, booster, cavity, synchrotron

1131

J. Rahighi, H. Ajam, R. Aslani, S. Fatehi, H. Ghasem, M.R. Khabazi, R. Safian, E. Salimi, A. Shahveh
IPM, Tehran, Iran
E. Ahmadi, M. Jafarzadeh, H.B. Jalali, M. Moradi, S. Pirani, M. Rahimi, A. Sadeghipanah, F. Saeidi, Kh.S. Sarhadi, A. Shahverdi
ILSF, Tehran, Iran
D. Einfeld
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The Iranian Light Source Facility Project (ILSF) is a 3rd generation light source with an energy of 3 GeV,a full energy injector and a 100 MeV linac as preinjector. For storage ring, booster synchrotron and linac including the transfer lines, a draft design has been completed and will be presented. The storage ring has an emittance of 3.3 nm-rad, a circumference of 297.6 meters with an overall of 32 straight sections of different lengths. The booster synchrotron has a circumference of 197 meters and emittance of 35nm-rad. For the booster synchrotron a new lattice is proposed. The linac is a conventional 150 MeV accelerator. The different accelerator components, magnets, girders, power supplies, vacuum systems etc. are in the design phase. State of the art design for different components is employed through international collaboration.

TUPPC004

Study of a Lattice with a Lower Emittance at SOLEIL

emittance, lattice, optics, betatron

1155

R. Nagaoka, P. Brunelle, A. Nadji, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

The paper introduces the first preliminary feasibility study made at SOLEIL towards a possible future upgrade of the lattice in furthermore reducing the horizontal emittance, so to raise the storage ring performance. The approach taken is to employ whatever emittance reduction methods available, by respecting the given constraints on the lattice structure and the optics, particularly the circumference, insertion device straights, the required optics behavior as well as its tunability. Specifically, the possibility of introducing superbends into the double bend lattice is pursued, which are beneficial to hard X-ray users and could simultaneously help reducing the emittance thanks to its longitudinally varying field profile. Although the present study shall mainly focus on the linear properties of the optical solutions found, optimization of nonlinear optics is also discussed in view of the large dependence of the latter on the former.

TUPPC006

CW Energy Upgrade of the Superconducting Electron Accelerator S-DALINAC

recirculation, linac, simulation, extraction

1161

M. Kleinmann, J. Conrad, R. Eichhorn, F. Hug, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: This work is supported by the DFG through SFB 634.
The S-DALINAC is a superconducting recirculating electron accelerator with maximum design energy of 130 MeV operating in cw at 3 GHz. Even so the gradients of the superconducting cavities are well above design, their design quality factor of 3*10⁹ have not been reached so far. Due to the limited cooling power of the cryo-plant being 120 W, the final energy achievable in cw operation is around 85 MeV, currently. In order to provide a cw beam with the designed final energy in the future, the installation of an additional recirculation path is projected and to be finished by 2013. We review the design constraints related to the existing beam lines, report in detail on the magnet design (being the key issue) and the lattice calculations for the additional recirculation path.

TUPPC012

Optics of Extraction Lines at CNAO

proton, ion, extraction, septum

1179

E. Bressi, L. Falbo, C. Priano, M. Pullia
CNAO Foundation, Milan, Italy
C. Biscari
INFN/LNF, Frascati (Roma), Italy

The CNAO (National Center for Oncological Hadrontherapy), is the first Italian center for deep hadrontherapy with proton and carbon ion beams, treating patients since fall 2011. The beam is delivered to the patient through a high energy transfer line (HEBT). The line is equipped with a horizontal switching dipole that carries the beam in three treatment rooms and a vertical switching dipole that allows a vertical delivery of the beam in the central treatment room. The CNAO HEBT commissioning has been carried out using proton and Carbon beams in the full range of energies: 60 to 250 MeV/u for protons, 120 to 400 MeV/u for Carbon ions. Optimization of the beam lines setup has been carried out for few energies, applying beam magnetic rigidity scaling for the full range in steps of the order of 1 MeV. The scaling has proven to be satisfactory for most elements, and only minor adjustments in the initial part of the line were needed to fulfill tolerances in all the range. Repeatability of magnetic settings is supported by measurements along the lines. Finally the results in terms of beam dimensions, beam transmission and beam position at the patient position are presented.

TUPPC036

Integration with the LHC of Electron Interaction Region Optics for a Ring-ring LHeC

quadrupole, proton, electron, optics

1239

L.N.S. Thompson
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Appleby
UMAN, Manchester, United Kingdom
N.R. Bernard
ETH, Zurich, Switzerland
H. Burkhardt, B.J. Holzer
CERN, Geneva, Switzerland
M. Fitterer
KIT, Karlsruhe, Germany
M. Klein
The University of Liverpool, Liverpool, United Kingdom
P. Kostka
DESY Zeuthen, Zeuthen, Germany

The Large Hadron Electron Collider (LHeC) project is a proposal to study e-p and e-A interactions at the LHC. One design uses an electron synchrotron to collide a 60GeV e± beam with the 7TeV proton beam. Designing a new accelerator around the existing LHC machine poses unique challenges, particularly in the interaction region (IR). The electron beam must be quickly separated from the proton beam after the interaction point (IP) to avoid beam-beam effects, while not significantly reducing luminosity or producing large amounts of synchrotron radiation. The proton beam must pass through the electron optics, while the electron beam must avoid the proton optics. The long straight section requires bending in both planes to counteract the IP crossing angle and to displace the beam vertically from the electron machine to the proton IP. An achromatic bending scheme is used in the vertical plane to eliminate dispersion at the IP and provide an optics which is well matched to the LHeC ring lattice. The interaction region and long straight section design is presented and detailed, and the design process and principles discussed.

TUPPC039

Synchrotron Radiation Studies for a Ring-Ring LHeC Interaction Region and Long Straight Section

electron, proton, quadrupole, synchrotron

1248

L.N.S. Thompson
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Appleby
UMAN, Manchester, United Kingdom
N.R. Bernard
ETH, Zurich, Switzerland
O.S. Brüning, B.J. Holzer
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom
P. Kostka
DESY Zeuthen, Zeuthen, Germany
B. Nagorny
DESY, Hamburg, Germany

The Large Hadron Electron Collider project is a proposal to study e-p and e-A interactions at the LHC. In the design for an electron synchrotron (alternative designs for a linac are also under development), a 60GeV e± beam is collided with a 7TeV LHC proton beam to produce TeV-scale collisions. Despite being much lower energy than the proton beam, the electron beam is high enough energy to produce significant amounts of synchrotron radiation (SR). This places strong constraints on beam optics and bending. In particular challenges arise with the complex geometry required by the long straight section (LSS) and interaction region (IR). This includes the coupled nature of the proton and electron optics, as SR produced by the electron beam must not be allowed to quench the superconducting proton magnets or create problems with beam-gas backgrounds. Despite this, the electron beam must be deflected significantly within the IR to produce sufficient separation from the proton beam.

TUPPC040

Model Calibration and Optics Correction Using Orbit Response Matrix in the Fermilab Booster

booster, optics, acceleration, coupling

1251

M.J. McAteer, S.E. Kopp
The University of Texas at Austin, Austin, Texas, USA
V.A. Lebedev, E. Prebys
Fermilab, Batavia, USA
A.V. Petrenko
BINP SB RAS, Novosibirsk, Russia

A beam-based method of optical model calibration using the measured orbit response matrix, known as the LOCO method, was successfully applied to Fermilab's rapid-cycling Booster synchrotron. Orbit responses were measured by individually changing the strength of each dipole corrector throughout the acceleration cycle, and dispersion was measured by changing the beam's radial offset. The model calibration procedure revealed large calibration errors for all elements in the Booster's recently-installed multipole corrector packages and beam position monitors. The resulting model was used to correct coupling and beta beating.

TUPPC041

A 3 TeV Muon Collider Lattice Design

quadrupole, emittance, lattice, collider

1254

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

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
A new lattice for 3 TeV c.o.m. energy with β^*=5mm was developed which follows the basic concept of the earlier 1.5 TeV design* but uses quad triplets for the final focus in order to keep the maximum magnet strength and aperture about the same as in 1.5 TeV case. Another difference is employment of combined-function magnets with the goal to lower heat deposition in magnet cold mass and to eliminate regions without bending field which produce “hot spots” of neutrino radiation that can be an issue at higher energy. The proposed lattice is shown to satisfy the requirements on luminosity, dynamic aperture and momentum acceptance.
* Y.Alexahin, E.Gianfelice-Wendt, A.Netepenko, Proc. IPAC10, Kyoto, May 2010, p. 1563

TUPPC042

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

multipole, 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.

TUPPC057

RHIC Spin Flipper Commissioning Results

resonance, polarization, injection, proton

1302

M. Bai, W.C. Dawson, J. Kewisch, Y. Makdisi, P. Oddo, C. Pai, P.H. Pile, T. Roser
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The five ac dipole design of RHIC spin flipper in the Blue ring was first commissioned during the RHIC 2012 polarized proton operation. The advantage of this design is to eliminate the vertical coherent betatron oscillations outside the spin flipper*. Spin flipping efficiency was measured with both 100 GeV and 250 GeV polarized proton beams. This paper presents the latest commissioning results.
* M. Bai , T. Roser, C. Dawson, Y. Makdisi, W. Meng, F. Meot, P. Oddo, C. Pai, P. Pile, RHIC Spin Flipper New Design and Commissioning Plan, IPAC10 proceedings, IPAC 2010, Kyoto, Japan, 2010

TUPPC058

Beam Energy Variation with Dipole Fault

sextupole, 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.

TUPPC059

Extraction of the Lie Map from Realistic 3D Magnetic Field Map

quadrupole, extraction, dynamic-aperture, lattice

1308

Y. Li
BNL, Upton, Long Island, New York, USA
X. Huang
SLAC, Menlo Park, California, USA

Funding: Supported by Department of Energy Contract No. DE-AC02-98CH10886.
We present a method to extract the Lie map of any arbitrary accelerator magnet from its actual 3D field map. After fitting a Taylor map from multi-particle tracking trajectories through the actual field, we factorize the map into a Lie map using Dragt-Finn's method. This method is validated by comparing with COSY-infinity for a soft-edge quadrupole model. Applications of extracting symplectic maps for the SPEAR and NSLS-II dipoles are shown as examples. A comparison of the map-tracking results against the direct field-integration-based method also is given.

TUPPC062

Transfer of Polarized 3He Ions in the AtR Beam Transfer Line

injection, ion, extraction, proton

1317

N. Tsoupas, W.W. MacKay, F. Méot, T. Roser, D. Trbojevic
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the US Department of Energy
In addition to collisions of electrons with various unpolarized ion species as well as polarized protons, the proposed electron-hadron collider (eRHIC) will also facilitate the collisions of electrons with polarized 3He ions. The AGS is the last acceleration stage of ions before injection into one RHIC for final acceleration. The AtR (AGS to RHIC) transfer line will be utilized to transport the polarized 3He ions from AGS into one of the RHIC’s collider rings. In this paper we investigate the extraction energy of the polarized 3He ions from the AGS which will optimize the polarization of 3He ions injected into RHIC. Some of the peculiarities (interleaved horizontal and vertical bends) of the AtR line's layout may degrade this spin matching of the polarized 3He ions. We will also discuss possible simple modifications of the AtR line to accomplish a perfect “spin matching” of the injected 3He beam with that of the stable spin direction at the injection point of the RHIC ring.

TUPPC067

How to Achieve Longitudinally Polarized Electrons using Integer Spin Tune Resonances

polarization, resonance, synchrotron, electron

1326

O. Boldt, A. Dieckmann, F. Frommberger, W. Hillert, J.F. Schmidt
ELSA, Bonn, Germany

Funding: Bundesministerium für Bildung und Forschung
Commonly, strong solenoids are used in circular accelerators to achieve longitudinal polarization. In practice, however, these solenoids cause a phase space coupling, which has to be compensated for by sophisticated decoupling schemes. We suggest to adiabatically ramp into an integer spin tune resonance, while preserving the degree of polarization. When appropriately adjusting the driving horizontal field contributions at the final energy, the resulting polarization is longitudinal at predefined positions in the accelerator. Here, depending on the energy spread, the degree of polarization is conserved for several seconds. The contribution shows the numerical analysis of this scenario being confirmed by first demonstration tests at the ELSA stretcher ring.

TUPPC072

Modeling of Matching Channel for Accelerator Complexes

controls, lattice, booster, quadrupole

1338

E.A. Podzyvalov, S.N. Andrianov
St. Petersburg State University, St. Petersburg, Russia
D. Zyuzin
FZJ, Jülich, Germany

Practically modern accelerator facility can be considered as a composite machines. Therefore it is necessary to consider special matching channels to joint all accelerator components together. For such channels advance various requirements, which can be formulated in the form of criteria sets. In this paper considered a global optimization concept allows to find appropriate solutions sets. This approach is demonstrated on the problem of modeling the matching channels for NICA accelerator complex.

TUPPC079

Tracking LHC Models with Thick Lens Quadrupoles: Results and Comparisons with the Standard Thin Lens Tracking

quadrupole, lattice, simulation, optics

1356

M. Giovannozzi, H. Burkhardt, T. Risselada
CERN, Geneva, Switzerland

So far, the massive numerical simulation studies of the LHC dynamic aperture were performed using thin lens models of the machine. This approach has the clear advantage of speed, but it has also the disadvantage of requiring re-matching of the optics from the real thick configuration to the thin one. Furthermore, as the figure-of-merit for the re-matching is the agreement between the beta-functions for the two model, while the quadrupole gradients are left free parameters, the effect of the magnetic multipoles might be affected by this approach and in turn the dynamic aperture computation. In this paper the new approach is described and the results for the dynamic aperture are compared with the old approach, including detailed considerations on the CPU-time requirements.

TUPPC098

Electron Polarization in the Medium-Energy Electron-Ion Collider at JLAB

polarization, electron, solenoid, closed-orbit

1386

F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang
JLAB, Newport News, Virginia, USA
D.P. Barber
DESY, Hamburg, Germany

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A key feature of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is high polarization (over 80%) of the electron beam at all collision points for the particle physics program. The equilibrium electron polarization is arranged to be vertical in the arcs of the figure-8 collider ring of the MEIC and anti-parallel to the arc dipole magnetic fields, in order to take advantage of the preservation of polarization by the Sokolov-Ternov (S-T) effect. Longitudinal polarization is achieved at collision points by utilizing energy-independent universal spin rotators each of which consists of a set of solenoids and dipoles placed at the end of an arc. The equilibrium beam polarization and its lifetime depend on competition between the S-T effect and radiative depolarization. The latter must be suppressed by spin matching. This paper reports on investigations of polarization in the MEIC electron collider ring and a preliminary estimate of beam polarization from calculations using the code SLICK.
Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

TUPPD008

Recent Progress Toward a Muon Recirculating Linear Accelerator

linac, cryomodule, quadrupole, factory

1422

K.B. Beard
Muons, Inc, Batavia, USA
M. Aslaninejad, C. Bonţoiu, A. Kurup, J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
S.A. Bogacz, V.S. Morozov, Y. Roblin
JLAB, Newport News, Virginia, USA

Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchrotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadrupoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.

TUPPD012

Complete Muon Cooling Channel Design and Simulations

emittance, simulation, solenoid, collider

1431

C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson
Muons, Inc, Batavia, USA
Y.S. Derbenev, V.S. Morozov
JLAB, Newport News, Virginia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD020

An EMMA Racetrack

quadrupole, injection, extraction, electron

1452

B.D. Muratori, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.L. Owen
UMAN, Manchester, United Kingdom

EMMA (Electron Machine for Many Applications) is the world’s first prototype non-scaling electron FFAG hosted at Daresbury Laboratory. Several upgrade possibilities for EMMA are explored, from creating a dispersion-free region in the ring to facilitate injection and extraction to making an insertion in EMMA by turning it into a racetrack-style machine. Alternative methods of injection and extraction into the EMMA ring are explored together with their feasibility and implications. The option of developing nested racetracks to achieve a particular desired energy is also explored.

TUPPD033

Conceptual Design of a Positron-annihilation System for Generation of Quasi-monochromatic Gamma Rays

positron, target, photon, electron

1476

R.J. Abrams, C.M. Ankenbrandt, K.B. Beard, G. Flanagan, R.P. Johnson, C. Y. Yoshikawa
Muons, Inc, Batavia, USA
A. Afanasev
GWU, Washington, USA

A conceptual design is presented for a system consisting of the following: an electron accelerator and production target to produce positrons, a dipole magnet and wedge to compress the positron momenta to be nearly monochromatic, a magnetic transport system to focus and direct the positrons to a converter, and a converter in which the positrons annihilate in flight to produce quasi-monochromatic gamma rays. The system represented is designed to produce ~10 MeV gammas, but it can also be designed for other energies.

TUPPD068

Design of the Production and Measurement of Ultra-Short Electron Bunches from an S-band RF Photoinjector

cavity, gun, electron, laser

1560

J.W. McKenzie, D. Angal-Kalinin, J.K. Jones, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The Electron Beam Test Facility (EBTF) is planned for installation in late 2012 at Daresbury Laboratory. An S-band RF photoinjector provides ultrashort, low emittance electron bunches up to 6 MeV. A suite of diagnostics has been designed to fully characterise the bunches. A particular focus has been on producing and measuring bunch lengths less than 100 fs. This can be achieved with a multi-cell standing wave S-band transverse deflecting cavity. Operating such a cavity with low energy electrons provides certain challenges which are discussed in this paper with respect to beam dynamic simulations.

TUPPP003

Status and Very First Commissioning of the ASTRID2 Synchrotron Light Source

cavity, septum, vacuum, synchrotron

1605

S.P. Møller, N. Hertel, J.S. Nielsen
ISA, Aarhus, Denmark

ASTRID2 is the new 10 nm UV and soft x-ray light source currently being built at Aarhus University, to replace the ageing source ASTRID. ASTRID2 is now in the end of its installation phase, with commissioning expected to take place during the spring. The status of the installation together with the first results of the commissioning will be presented.

TUPPP007

Modifications to the Machine Optics of BESSY II Necessitated by the EMIL Project

undulator, optics, cryogenics, storage-ring

1614

P.O. Schmid, J. Bahrdt, T. Birke, R. Follath, P. Kuske, D. Simmering, G. Wüstefeld
HZB, Berlin, Germany

The Helmholtz Zentrum Berlin and the Max Planck Society are going to build a new dedicated X-ray beam line at the synchrotron source light source BESSY II which will be used for analyzing materials for renewable energy generation. The new large scale project has been dubbed EMIL. In this document we present the modifications to the machine optics and to what extent these changes affect the performance of BESSY II.

TUPPP017

Lattice Design of the SSRF Storage Ring with Superbend

lattice, emittance, photon, optics

1644

S.Q. Tian, B.C. Jiang, H.H. Li, M.Z. Zhang, W.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

The SSRF storage ring is being investigated by upgrading with normal conducting superbend of 3 T. The bending magnets are shortened, and thus some additional straight sections with the length of about 2 m are created in the center of the arc cell. They can be used to install more insertion devices. The lattice adjustment and the optics design are presented in this paper, where much efforts are made to maintain the effective emittance along the ring with respect to the nominal optics.

TUPPP019

Overview of the Solaris Facility

linac, storage-ring, klystron, vacuum

1650

C.J. Bocchetta, M. Bartosik, P.P. Goryl, K. Królas, M. Młynarczyk, W. Soroka, M.J. Stankiewicz, P.S. Tracz, Ł. Walczak, A.I. Wawrzyniak, K. Wawrzyniak, J.J. Wiechecki, M. Zając, L. Zytniak
Solaris, Kraków, Poland
R. Nietubyć
The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland

Funding: Work supported by the European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09
The Polish synchrotron light source Solaris is under construction in Kraków. The project is based on the MAX IV light source being built in Lund, Sweden. The 1.5 GeV storage ring for Solaris and part of the injector complex are identical to that of MAX IV, although both are housed in buildings that differ from those of MAX IV. Ground breaking on the green field site at the Jagiellonian University campus occurred at the start of 2012. A detail description of the facility infrastructure, services and construction choices is given together with the latest project developments for main accelerator systems.

TUPPP024

Recent Progress on the MAX IV 1.5 GeV Storage Ring Lattice and Optics

storage-ring, lattice, vacuum, sextupole

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.

TUPPP065

Progress Report on the SwissFEL Injector Test Facility

emittance, quadrupole, laser, optics

1747

T. Schietinger, M. Aiba, S. Bettoni, B. Beutner, M. Csatari, K. Doshekenov, Y.-C. Du, M.W. Guetg, C.P. Hauri, R. Ischebeck, F. Le Pimpec, N. Milas, G.L. Orlandi, M. Pedrozzi, P. Peier, E. Prat, S. Reiche, B. Smit, A. Trisorio, C. Vicario
Paul Scherrer Institut, Villigen, Switzerland

The SwissFEL injector test facility at the Paul Scherrer Institute is the principal test bed and demonstration plant for the SwissFEL project, which aims at realizing a hard-X-ray Free Electron Laser by 2017. The RF photoinjector facility has been in operation since 2010 and has recently reached its design energy of 250 MeV. A newly installed movable magnetic chicane allows longitudinal bunch compression studies. We report on the first experience with the bunch compressor and present the latest results of projected and slice emittance measurements.

Poster TUPPP065 [1.801 MB]

TUPPP076

Soft Orbit Bumps for Duke Storage Ring VUV FEL Operation

FEL, radiation, wiggler, electron

1774

S.F. Mikhailov, J.Y. Li, V. Popov, P.W. Wallace, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DoE grant # DE-FG02-97ER41033.
The Duke FEL and High Intensity Gamma-ray Source (HIGS) facility is operated with an electron beam from 0.24 to 1.2 GeV and a photon beam from 190 to 1060 nm. The current range of the gamma-beam energy is from 1 MeV to about 100 MeV, with the maximum total gamma-flux of more then 10¹⁰ gammas per second around 10 MeV. Production of the high intensity, high energy gamma-beams of 60-100 MeV using UV-VUV mirrors of 240 - 190 nm requires and high energy, high current electron beams of 0.9-1.05 GeV. The radiation damage problem becomes more severe for VUV FEL operation below 190 nm. The radiation from the End-of-Arc (EOA) bending magnets, instead of the radiation from FEL wigglers, is the dominant cause of a rapid degradation of the downstream FEL mirror. In this work, we propose a number of measures to significantly reduce the radiation from these dipole magnets as well as other potential sources of synchrotron radiation toward the FEL mirror. In particular, we describe the development of an orbit bump using designated "soft" orbit correctors. The magnetic field of these correctors is limited to produce a radiation with a critical wavelength close or below the FEL wavelength.

TUPPR006

Design Progress and Construction Status of SuperKEKB

quadrupole, status, wiggler, klystron

1822

H. Koiso, K. Akai, K. Oide
KEK, Ibaraki, Japan

KEKB operation finished in June 2010, and the upgrade of KEKB to SuperKEKB has commenced. The design luminosity of SuperKEKB is 8×10³⁵cm^-2s^-1, which is 40 times higher than that of KEKB. The design strategy for SuperKEKB is based on the Nano-Beam Scheme, where the vertical beam sizes of the low-energy positron ring and the high-energy electron ring are squeezed to 50−60 nm at the interaction point with a large Piwinski angle. The beam currents in both rings will be double those in KEKB. Finalizing the design of the interaction region is going on by using precise modeling of beam optics. Dismantling KEKB rings and fabrication of accelerator components for SuperKEKB including magnets, power supplies, and antechamber-type beam pipes have already started. This paper describes design progress and construction status of SuperKEKB.

TUPPR008

One 233 km Tunnel for Three Rings: e⁺e^-, p-pbar, and μ⁺+μ⁻

collider, emittance, luminosity, lattice

1828

G.T. Lyons, L.M. Cremaldi, A. Datta, M. Duraisamy, T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA

Funding: Supported by DE-FG05-91ER40622
In 2001, a cost analysis was conducted to build a 233 km circumference tunnel in northern Illinois for a Very Large Hadron Collider (VLHC). Here we outline the implementations of e⁺e⁻, proton anti-proton, and μ⁺+ μ⁻ collider rings in such a tunnel using recent technological innovations. The 500 GeV e⁺e⁻ collider employs a Crab Waist Crossing, ultra low emittance damped bunches, a vertical IP focal length of 0.06 cm, 12 GV of superconducting RF, and 0.026 Tesla low coercivity, grain oriented silicon steel/concrete dipoles. The 40 TeV proton anti-proton collider uses the high intensity Fermilab anti-proton source, exploits high cross sections for proton anti-proton production of high mass states, and uses 2 Tesla 0.005% ultra low carbon steel/YBCO superconductor magnets run with liquid neon. The 40 TeV muon ring ramps the 2 Tesla superconducting magnets at 8 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 2 to 20 TeV in 72 orbits with 72% survival, and mitigates neutrino radiation with a phase shifting, roller coaster FODO lattice.*
* G. T. Lyons, http://arxiv.org/pdf/1112.1105

TUPPR015

Choke-Mode Damped Structure Design for the CLIC Main Linac

wakefield, damping, simulation, impedance

1840

H. Zha, H. Chen, W.-H. Huang, C.-X. Tang
TUB, Beijing, People's Republic of China
A. Grudiev, J. Shi, W. Wuensch
CERN, Geneva, Switzerland

Choke-mode damped accelerating structures are being studied as an alternative to the CLIC waveguide damped baseline structure. Choke-mode structures hold the potential for much lower pulsed surface heating and reduced cost since no milling is required. We propose a new choke geometry which has significant suppression of higher order dipoles. By impedance matching and detuning of the first dipole pass-band, the wakefield suppression is comparable to the baseline design with waveguide damping. A fully featured choke mode structure with the same accelerating gradient profile and filling time as the nominal CLIC design has been designed. It has the potential to replace the waveguide damped design without changing any of the machine layout or the beam parameters.

TUPPR027

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

cavity, multipole, 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.

TUPPR037

Simulations of Higher Order Modes in the ACC39 Module of FLASH

cavity, HOM, higher-order-mode, simulation

1900

I.R.R. Shinton, R.M. Jones, P. Zhang
UMAN, Manchester, United Kingdom
Z. Li
SLAC, Menlo Park, California, USA

This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39 currently installed and in operation at FLASH and due to be installed at XFEL . Coupled inter-cavity modes are simulated together with a limited band of trapped modes. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. In this way the nature of the multi-cavity nature of these modules is investigated with implications for a HOM-based BPM system and direct comparison to experimental results.

TUPPR056

Parametric Study of the CLIC Damping Rings Delay Ring for Reaching Isochronicity Conditions

sextupole, 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.

TUPPR069

Calculation of Wakefields in 17-GHz Beam-Driven Photonic Bandgap Accelerator Structure

wakefield, simulation, damping, electron

1981

M. Hu, B.J. Munroe, M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA

We present computer simulations of the wakefields in a six cell Photonic Bandgap (PBG) structure at 17GHz. Using the commercial code CST Particle Studio, the major accelerating mode (TM01) and dipole mode (TM11) are identified. The modes are excited by passing an 18MeV electron beam through the structure. The comparisons of the wakefields in an elliptical-rod PBG structure, round-rod PBG structure, and disc-loaded waveguide structure are carried out to verify experimental results. Various parameters, such as the beam charge and position, are varied to analyze the amplitude and decay time of the wakefields in the three structures. All of the simulation results will guide the design of next generation high gradient accelerator PBG structures.

TUPPR075

Challenges for the Magnet System of LHeC

electron, quadrupole, proton, linac

1996

S. Russenschuck, B.J. Holzer, G. Kirby, A. Milanese, R. Tomás, D. Tommasini, F. Zimmermann
CERN, Geneva, Switzerland

The main challenges for the normal conducting magnet system are the very compact, low field, and high precision magnets for the ring-ring option and their rapid installation in the crowded LHC tunnel. The superconducting triplet magnets require strong gradients for the protons in close vicinity of a field-free region for the electrons. The field requirements for the ring-ring option allow a number of different magnet designs using the well-proven Nb-Ti superconductor technology and making use of the cable development for the LHC. The separation distance between the electron and proton beams in Q1 requires a half-aperture quadrupole design to limit the overall synchrotron radiation power emitted by the bending of the electron beam. The requirements in terms of aperture and field gradient are more difficult to obtain for the Linac-Ring option. Consequently we present the limitations for the field gradient and septum size achievable with both Nb-Ti and Nb3Sn superconducting technologies.

TUPPR076

The LHeC Project Development Beyond 2012

electron, linac, collider, cavity

1999

F. Zimmermann, O.S. Brüning
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom

The LHeC study group is finalizing a Conceptual Design Report for publication early in 2012. This paper discusses the next steps required for developing a Technical Design Report and highlights the R&D developments, test facilities and implementation studies that need to be addressed over the coming years. Particular emphasize will be given to similarities with other ongoing accelerator and detector studies, and to a discussion of possible international collaboration efforts.

TUPPR080

Integration of Detector into Interaction Region at MEIC

ion, solenoid, optics, electron

2011

V.S. Morozov, R. Ent, P. Nadel-Turonski
JLAB, Newport News, Virginia, USA
C. Hyde
Old Dominion University, Norfolk, Virginia, USA

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Jefferson Lab's Medium-energy Electron Ion Collider (MEIC) is proposed as a next-generation facility for the study of strong interaction (QCD). Accessing the relevant physics requires a full-acceptance detector with a dedicated small-angle high-resolution detection system capable of covering a wide range of momenta (and charge-to-mass ratios) with respect to the original ion beam. We present a design of such a detection system integrated into the collider's interaction region, in which full acceptance is attained by letting small-angle collision products pass through the nearest elements of the machine final-focusing system for further detection. The proposed design is consistent with the current collider optics and demonstrates an excellent performance in terms of detector acceptance and resolution.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

TUPPR085

Recycler Chromaticities and End Shims for NOvA at Fermilab

lattice, sextupole, quadrupole, dynamic-aperture

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.

WEYA02

Studies at CesrTA of Electron-Cloud-Induced Beam Dynamics for Future Damping Rings

electron, simulation, emittance, damping

2081

G. Dugan, M.G. Billing, K.R. Butler, J.A. Crittenden, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, K.G. Sonnad, H.A. Williams
CLASSE, Ithaca, New York, USA
R.F. Campbell, R. Holtzapple, M. Randazzo
CalPoly, San Luis Obispo, California, USA
J.Y. Chu
CMU, Pittsburgh, Pennsylvania, USA
J.W. Flanagan, K. Ohmi
KEK, Ibaraki, Japan
M.A. Furman, M. Venturini
LBNL, Berkeley, California, USA
M.T.F. Pivi
SLAC, Menlo Park, California, USA

Funding: US National Science Foundation PHY-0734867, PHY-1002467, and PHY-1068662; US Dept. of Energy DE-FC02-08ER41538; and the Japan/US Cooperation Program.
Electron clouds can adversely affect the performance of accelerators, and are of particular concern for the design of future low emittance damping rings. Studies of the impact of electron clouds on the dynamics of bunch trains in CESR have been a major focus of the CESR Test Accelerator program. In this paper, we report measurements of coherent tune shifts, emittance growth, and coherent instabilities carried out using a variety of bunch currents, train configurations, beam energies, and transverse emittances, similar to the design values for the ILC damping rings. We also compare the measurements with simulations which model the effects of electron clouds on beam dynamics, to extract simulation model parameters and to quantify the validity of the simulation codes.

Slides WEYA02 [2.033 MB]

WEOBA01

Construction Progress of the RHIC Electron Lenses

electron, solenoid, gun, proton

2125

W. Fischer, Z. Altinbas, M. Anerella, E.N. Beebe, M. Blaskiewicz, D. Bruno, W.C. Dawson, D.M. Gassner, X. Gu, R.C. Gupta, K. Hamdi, J. Hock, L.T. Hoff, A.K. Jain, R.F. Lambiase, Y. Luo, M. Mapes, A. Marone, T.A. Miller, M.G. Minty, C. Montag, M. Okamura, A.I. Pikin, S.R. Plate, D. Raparia, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, P. Wanderer, S.M. White, W. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
In polarized proton operation, the RHIC performance is limited by the head-on beam-beam effect. To overcome these limitations two electron lenses are under construction. We give an overview of the progress over the last year. Guns, collectors and the warm electron beam transport solenoids with their associated power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of gun, collector and some of the instrumentation. The RHIC infrastructure is being prepared for installation, and simulations continue to optimize the performance.

Slides WEOBA01 [7.672 MB]

WEOBA02

Tevatron End-of-Run Beam Physics Experiments

antiproton, proton, emittance, luminosity

2128

A. Valishev
Fermilab, Batavia, USA
X. Gu, R. Miyamoto, S.M. White
BNL, Upton, Long Island, New York, USA
J. Qiang
LBNL, Berkeley, California, USA
F. Schmidt
CERN, Geneva, Switzerland

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP).
Before the Tevatron collider Run II ended in September of 2011, a two-week period was devoted to the experiments on various aspects of beam-beam interactions. The studied topics included offset collisions, coherent beam stability, effect of the bunch-length-to-beta-function ratio, and operation of AC dipole with colliding beams. In this report we summarize the results of beam experiments and supporting simulations.

Slides WEOBA02 [1.382 MB]

WEEPPB010

RF Modeling Using Parallel Codes ACE3P for the 400-MHz Parallel-Bar/Ridged-Waveguide Compact Crab Cavity for the LHC HiLumi Upgrade

damping, cavity, HOM, impedance

2185

Z. Li, L. Ge
SLAC, Menlo Park, California, USA
J.R. Delayen, S.D. Silva
ODU, Norfolk, Virginia, USA

Funding: Work partially supported by the US DOE through the US LHC Accelerator Research Program (LARP), and by US DOE under contract number DE-AC02-76SF00515.
Schemes utilizing crab cavities to achieve head-on beam-beam collisions were proposed for the LHC HiLumi upgrade. These crabbing schemes require that the crab cavities be compact in order to fit into the tight spacing available in the existing LHC beamlines at the location where the crab cavities will be installed. Under the support of US LARP program, Old Dominion University and SLAC have joint efforts to develop a 400-MHz compact superconducting crab cavity to meet the HiLumi upgrade requirements. In this paper, we will present the RF modeling and analysis of a parallel-bar/ridged-waveguide shaped 400-MHz compact cavity design that can be used for both the horizontal and vertical crabbing schemes. We will also present schemes for HOM damping and multipacting analysis for such a design.

WEEPPB013

Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR

quadrupole, octupole, background, multipole

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.

WEEPPB014

The Magnetic Model of the LHC during the 3.5 TeV Run

quadrupole, injection, controls, optics

2194

E. Todesco, N. Aquilina, M. Giovannozzi, M. Lamont, F. Schmidt, R.J. Steinhagen, M. Strzelczyk, R. Tomás
CERN, Geneva, Switzerland
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

The magnetic model of the LHC is based on a fit of the magnetic measurements through equations that model the field components (geometric, saturation, persistent) at different currents. In this paper we will review the main results related to the magnetic model during the run of the LHC in 2010-2011: with a top energy of 3.5 TeV, all components of the model but the saturation are visible. We first give an estimate of the reproducibility of the main components and multipolar errors as they can be deduced from beam measurements, i.e. orbit, tune, chromaticity, beta beating and coupling. We then review the main results relative to the decay at injection plateau, dependence on powering history, and snapback at the beginning of the ramp for both tune and chromaticity. We discuss the precision obtained in tracking the magnets during the ramp, where the persistent current components gradually disappear. We conclude by presenting the behaviour of the quadrupoles model during the squeeze. A list of the major changes implemented during the operation together with what are considered as the main open issues is given.

WEPPC053

SSR1 HOM Analysis and Measurements

HOM, quadrupole, cavity, higher-order-mode

2333

M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Single spoke resonators (SSR1, β=0.22) are currently under development for Project X at Fermilab. In this paper, extensive Higher Order Mode (HOM) analysis carried out on SSR1 is reported including the simulated R/Q for monopoles, dipoles, and quadrupoles. HOM measurements carried out on several spoke cavities are also reported including the harmonic response and the bead pull measurements. Comparison between the measured R/Q values and the simulated ones are presented.

WEPPC086

Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cyromodule

cavity, damping, HOM, impedance

2414

L. Xiao, Z. Li, C.-K. Ng
SLAC, Menlo Park, California, USA
A. Nassiri, G.J. Waldschmidt, G. Wu
ANL, Argonne, USA
R.A. Rimmer, H. Wang
JLAB, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A single-cell superconducting deflecting cavity operating at 2.812 GHz has been proposed and designed for the Short Pulse X-ray (SPX) project for the Advanced Photon Source upgrade. A cryomodule of 4 such cavities will be needed to produce the required 2-MV deflecting voltage. Each deflecting cavity is equipped with one fundamental power coupler (FPC), one lower order mode (LOM) coupler, and two higher order mode (HOM) couplers to achieve the stringent damping requirements for the unwanted modes. The damping of the HOM/LOM modes below the beampipe cutoff has been analyzed in the single cavity geometry and shown to meet the design requirements. The HOMs above beam pipe cutoff in the 4-cavity cyromodule, however, may result in cross coupling which may affect the HOM damping and potentially trapped modes between the cavities which could produce RF heating to the beamline bellows and even be detrimental to the beam. We have evaluated the HOM damping and trapped modes in the 4-cavity cryomodule using the parallel finite element EM code ACE3P developed at SLAC. We will present the results of the cryomodule analysis in this paper.

WEPPC087

Second Harmonic Cavity Design for Project-X Main Injector

cavity, simulation, HOM, impedance

2417

L. Xiao, C.-K. Ng
SLAC, Menlo Park, California, USA
J.E. Dey, I. Kourbanis
Fermilab, Batavia, USA

In order to accelerate the proposed beam intensity for Project-X, a new RF system for Main Injector (MI) will be required. A new 53 MHz first harmonic RF cavity that meets the MI requirements for Project-X has been designed. In order to reduce the peak longitudinal beam density a 10⁶ MHz second harmonic RF system is also needed. The first harmonic RF cavity design is a quarter wave coaxial resonator with a single accelerating gap and a perpendicular biased ferrite tuner. The second harmonic RF cavity baseline design is similar to the fundamental one and scaled down from it. RF simulations and shape optimizations on the second harmonic cavity are carried out to obtain the optimal performance which meets Project-X requirements. The results are discussed and presented in this paper.

WEPPD011

Study of the Pressure Profile Inside the NEG Coated Chambers of the SIS 18

vacuum, simulation, quadrupole, ion

2519

M.C. Bellachioma, H. Kollmus, A. Krämer, J. Kurdal, H. Reich-Sprenger, L. Urban, M. Wengenroth
GSI, Darmstadt, Germany

In the context of the technical developments for the construction of FAIR at GSI, an intensive programme for the vacuum upgrade of the existing SIS 18 was started in 2005, with the aim to improve the beam lifetime and intensity. To reach these purposes also the installation of NEG coated dipole and quadrupole chambers is foreseen. During the upgrade shutdowns performed between 2006 and 2009 the vacuum chambers of approximately 65% of the SIS18 circumference were replaced by NEG coated pipes. To evaluate in detail the pressure profile inside the coated chambers mounted into the accelerator a dedicated experimental set-up, which reproduces a vacuum environment similar to the one of the SIS 18, was built. Using three gauges, mounted in different positions of a coated chamber, it was possible to measure the pressure in the range of 10^-12 mbar inside the activated NEG pipe and 10^-11 mbar outside the pipe at the pumping posts. Additionally, a modelling of a SIS18 vacuum sector was realised and the pressure variation values obtained by a Monte-Carlo simulation were compared with those measured. In this paper the experimental results and the vacuum simulations are described and discussed.

WEPPD043

The Studies of Power System Harmonics at TLS

coupling, power-supply, cryogenics, controls

2609

T.-S. Ueng, J.-C. Chang, Y.F. Chiu, K.C. Kuo, Y.-C. Lin
NSRRC, Hsinchu, Taiwan

The power system harmonic distortion in the utility system of NSRRC is investigated for improving the power system performance. The monitored power quality data at the point of common coupling is examined and compared with industrial standards. In addition, the harmonic characteristics of electric power for the accelerator magnets and adjustable speed drives which contribute the most harmonics are analyzed. Furthermore, the approach to mitigate the harmonic effects for improving the power quality is studied.

WEPPD079

Measurements of Magnetic Permeability of Soft Steel at High Frequencies

impedance, booster, vacuum, damping

2711

Y. Tokpanov, V.A. Lebedev, W. Pellico
Fermilab, Batavia, USA

The Fermilab Booster does not have a vacuum chamber which would screen the beam from laminations its dipoles cores. Therefore the booster impedance is mainly driven by the impedance of these dipoles. Recently an analytical model of the laminated dipole impedances was developed. However to match the impedance measurements with calculations one needs an accurate measurement of soft steel magnetic permeability. This paper presents the measurement results of the permeability in a frequency range from ~10 MHz to 1 GHz. Measurements of e.-m. wave propagation in 30 cm long strip line built from soft steel were used to compute the permeability. Measurements were performed in a DC magnetic field to observe the effect of steel saturation on the high frequency permeability. Both real and imaginary parts of the permeability were measured. As expected their values were decreasing with frequency increase from 10 MHz to 1 GHz and with saturation of steel DC permeability.
Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.

WEPPD081

Optimization of AC Dipole Parameters for the Mu2e Extinction System

proton, emittance, magnet-design, electron

2714

E. Prebys
Fermilab, Batavia, USA

The Mu2e experiment is being planned at Fermilab to measure the rate for muons to convert to electrons in the field of an atomic nucleus with unprecedented precision. This experiment uses an 8 GeV primary proton beam consisting of short (~200 nsec FW) bunches, separated by 1.7 μs. It is vital that out-of-bunch beam be suppressed at the level of 10^-10 or less. This poster describes the parametric analysis which was done to determine the optimum harmonics and magnet specifications for this system, as well as the implications for the beam line optics.

WEPPD084

The E-Lens Test Bench for Rhic Beam-Beam Compensation

electron, gun, controls, cathode

2720

X. Gu, Z. Altinbas, J.N. Aronson, E.N. Beebe, W. Fischer, D.M. Gassner, K. Hamdi, J. Hock, L.T. Hoff, P. Kankiya, R.F. Lambiase, Y. Luo, M. Mapes, J.-L. Mi, T.A. Miller, C. Montag, S. Nemesure, M. Okamura, R.H. Olsen, A.I. Pikin, D. Raparia, P.J. Rosas, J. Sandberg, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, W. Zhang
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.
To compensate for the beam-beam effects from the proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are fabricating two electron lenses that we plan to install at RHIC IR10. Before installing the e-lenses, we are setting-up the e-lens test bench to test the electron gun, collector, GS1 coil, modulator, partial control system, some instrumentation, and the application software. Some e-lens power supplies, the electronics for current measurement will also be qualified on test bench. The test bench also was designed for measuring the properties of the cathode and the profile of the beam. In this paper, we introduce the layout and elements of the e-lens test bench; and we discuss its present status towards the end of this paper.

WEPPP004

A Reciprocity Principle for Wakefields in a Two-Channel Coaxial Dielectric Structure

wakefield, vacuum, simulation, acceleration

2726

G.V. Sotnikov
NSC/KIPT, Kharkov, Ukraine
J.L. Hirshfield, T.C. Marshall, G.V. Sotnikov
Omega-P, Inc., New Haven, USA
S.V. Shchelkunov
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA

Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics.
The reciprocity principle* is often used in applications of classical electromagnetism. We have employed this principle for testing wakefields set up by an electron bunch in a two-channel coaxial dielectric structure (CDWA)**. For numerical studies we take a ~1-THz fused silica structure which we plan to test at FACET/SLAC; it has dimensions: outer shell, OD=800 μm, ID=500 μm; inner shell OD=181 μm, ID=50 μm. The structure is energized by a 23-GeV, 3-nC bunch having axial RMS size=25 μm. FACET has no drive bunch of annular shape as required for a CDWA; nevertheless, our analytical studies and simulations prove that for the axial wakefield, an annular drive bunch can be replaced by a pencil-like bunch of the same charge traveling in the annular vacuum channel. The longitudinal electric field along the accelerator channel axis (as recorded by a witness bunch) set up by this pencil-like bunch is the same as in the conventional structure of the CDWA. Moreover, if we interchange the drive bunch and the witness bunch, the witness bunch will register the same axial wakefield. However, the stability of the annular bunch is far superior to that of the pencil bunch.
*L. D. Landau and E. M. Lifshitz, Electrodynamics of Continuous Media (Addison-Wesley: Reading, MA, 1960).
**G. Sotnikov et al., PRST-AB, 061302 (2009).

WEPPP020

Rebunching Low Energy Neutrons by Magnetic Acceleration and Deceleration

neutron, acceleration, controls, focusing

2766

Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Arimoto, H.M. Shimizu
KEK, Ibaraki, Japan
P.W. Geltenbort
ILL, Grenoble, France
S. Imajo
Kyoto University, Kyoto, Japan
M. Kitaguchi
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Seki
RIKEN Nishina Center, Wako, Japan
T. Yoshioka
Kyushu University, Fukuoka, Japan

Funding: Supported by the Grant-in-Aid for Creative Scientific Research of MEXT under the Program 19GS0210, the Quantum Beam Fundamentals Development Program of the MEXT, and KEK Neutron Program 2009S03.
Ultra cold neutrons (UCN) - neutrons with energies less than 300 neV - can be accelerated or decelerated by means of static magnetic and RF fields. The method and experimental setup will be described in detail and the results of a recent first test experiment will be presented. The detail cannot be disclosed until the paper is published.

WEPPP042

Experimental Demonstration of Wakefield Effects in a 250 GHz Planar Diamond Accelerating Structure

wakefield, radiation, acceleration, electron

2816

S.P. Antipov, J.E. Butler, C.-J. Jing, A. Kanareykin, P. Schoessow, S.S. Zuo
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
W. Gai
ANL, Argonne, USA

Funding: DOE SBIR
We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism. Fields produced by a first, drive, beam were used to accelerate a second, witness, electron bunch which followed the driving bunch at an adjustable distance. The energy gain of the witness bunch as a function of its separation from the drive bunch is a direct measurement of the wake potential. We also present wakefield mapping results for THz quartz structures. In this case decelerating wake inside the bunch is inferred from the drive beam energy modulation.

WEPPP061

A Method to Obtain the Frequency of the Longitudinal Dipole Oscillation for Modeling and Control in Synchrotrons with Single or Double Harmonic RF Systems

synchrotron, controls, ion, emittance

2846

J. Grieser, J. Adamy, D.E.M. Lens
TU Darmstadt, RTR, Darmstadt, Germany
H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This work was partly funded by GSI Helmholtzzentrum für Schwerionenforschung GmbH
In a heavy-ion synchrotron the bunched beam can perform longitudinal oscillations around the synchronous particle (single bunch dipole oscillation, SBDO). If disturbances/instabilities exciting the SBDO exceed the rate of Landau damping, the beam can become unstable. Furthermore, Landau damping is accompanied by an increase of the beam emittance which may be undesired. Thus, control efforts are taken to stabilize the beam and to keep the emittance small. It is known that for a single harmonic cavity and a small bunch the SBDO oscillates with the synchrotron frequency* if the oscillation amplitudes are small. For a larger bunch or a double harmonic RF systems that introduces nonlinearities**, this is no longer valid. This work shows how the frequency of the SBDO can be determined in general. As a result, the SBDO can again be modeled as a harmonic oscillator with an additional damping term to account for Landau damping. This model can be used for feedback designs which is shown by means of a simple example. As the frequency of the SBDO and the damping rate depend on the size of the bunch in phase space, it is shown how this information can be obtained from the measured beam current.
* F. Pedersen and F. Sacherer, IEEE Transactions on Nuclear Science, 24:1296–1398, 1977
** A. Hofmann and S. Myers, Proc. of the 11th International Conference on High Energy Acceleration, 1980

WEPPP064

Design and Simulation of the Stripline Transverse Quadrupole Kicker for HLS II

quadrupole, kicker, impedance, storage-ring

2852

F.F. Wu, W.B. Li, P. Lu, T.J. Ma, B.G. Sun, Y.Y. Xiao, H. Xu, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

In order to investigate the possibility of excite a transverse quadrupole mode oscillation of the electron bunch in the HLS II storage ring, we design a stripline transverse quadrupole kicker. The characteristic impedance of some modes(dipole modes, sum mode, quadrupole mode) of the optimised stripline kicker must match 50Ω characteristic impedance of the external transmission lines so as to reduce the reflected power. We use nonlinear least square method to optimise the kicker and compare characteristic impedances of calculation using 2D Possion code and fitted function of several variables, then we get optimised size with integrated use of Possion code and fitted function of several variables. Using the 2D Poisson code, we simulate the electric field distribution of dipole modes when the horizontal or the vertical electrodes are at opposite unit potentials, and the electric field distribution of quadrupole mode using quadrupole kick. We verified that the designed stripline kicker can excite a transverse quadrupole mode oscillation of the electron bunch.

WEPPP070

Simulation of the APS Storage Ring Orbit Real-Time Feedback System Upgrade Using MATLAB

feedback, storage-ring, simulation, controls

2870

S. Xu, G. Decker, R.I. Farnsworth, F. Lenkszus, H. Shang, X. Sun
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.
The Advanced Photon Source (APS) storage ring orbit real-time feedback (RTFB) system plays an important role in stabilizing the orbit of the stored beam. An upgrade is planned that will improve beam stability by increasing the correction bandwidth to 200 Hz or higher. To achieve this, the number of available steering correctors and beam position monitors (BPMs) will be increased, and the sample rate will be increased by an order of magnitude. An additional benefit will be the replacement of aging components. Simulations have been performed to quantify the effects of different system configurations on performance.

WEPPP083

Near Real-time Response Matrix Calibration for 10-Hz GOFB

feedback, damping, injection, quadrupole

2903

C. Liu, R.L. Hulsart, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 10-Hz global orbit feedback, for damping the trajectory perturbation (~10 Hz) due to the vibrations of the triplets, is operational for injection and store in RHIC. The operation of the system has been performed using transfer functions between the beam position monitors and correctors obtained from the online optics model and a correction algorithm based on singular value decomposition (SVD). Calibration of the transfer functions by measuring the beam position oscillations while modulating the dedicated correctors has been carried out. The feedback results with model matrix and measured matrix will be compared.

WEPPR027

Complete Electromagnetic Design of the ESS-Bilbao RFQ Cold Model

rfq, quadrupole, simulation, radio-frequency

2991

A. Vélez, I. Bustinduy, J. Feuchtwanger, N. Garmendia, O. González, I. Madariaga, J.L. Muñoz, D. de Cos
ESS Bilbao, Bilbao, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
V. Etxebarria, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain

In this work, the ESS-Bilbao 352,2 Mhz RFQ Cold Model to be built in the ESS-Bilbao accelerator facility is presented. The Cold Model intends to be a small scale representation of the final 4 meters long RFQ which will be able to accelerate a 75 mA proton beam from 75 keV to 3 MeV. The work shown here covers the complete electromagnetic design process of the Cold Model which will be built in aluminium with a total length of 1 meter. Moreover, in order to find out fabrication tolerances, a longitudinal test modulation in the vane regions similar to the one designed for the final RFQ is included in the Cold Model. This modulation represents also a useful tool in order to test the agreement between measurements and electromagnetic simulations. In addition, a complete parametric study of the RFQ ends and radial matchers is presented as an important design parameter able to adjust the field flatness. Finally, slug tuning rods are also added to be able to test the tuning procedures. A final RFQ Cold Model prototype has been designed and is currently under fabrication.

WEPPR033

Performance of Low-Energy Magnetic Bunch Compression for the ASTA Photoinjector at Fermilab

simulation, emittance, cryomodule, collective-effects

3006

C.R. Prokop, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
B.E. Carlsten
LANL, Los Alamos, New Mexico, USA
M.D. Church
Fermilab, Batavia, USA

Funding: LANL LDRD program, project 20110067DR -U.S. DOE Contract No. DE-FG02-08ER41532 and DE-AC02-07CH11359.
The Advanced Superconducting Test Accelerator (ASTA) at Fermilab incorporates a magnetic bunch compressor chicane to compress the 40-MeV electron bunches generated in the photoinjector. In this paper, we present a numerical analysis and parametric study of the bunch compressor's performance for various operating scenarios. The beam dynamics simulations, carried out with Astra, Impact-Z and CSRTrack, are compared against each other. Finally, an operating regime with low phase space dilutions is suggested based on the simulation results.

WEPPR047

The Effect of Non-Zero Closed Orbit on Electron-Cloud Pinch Dynamics

electron, quadrupole, proton, simulation

3033

G. Franchetti
GSI, Darmstadt, Germany
F. Zimmermann
CERN, Geneva, Switzerland

A study on the pinch dynamics of electron cloud during a bunch passage under the effect of a single arbitrary-order multipole was presented at IPAC2011. The complexity of the pinch pattern is directly related to the order of the multipolar field. However, in a realistic situation, the proton beam will not be located in the center of the vacuum chamber. If the beam is offset a new pinch regime is encountered, where feed-down effects and asymmetry of pinch density render the dynamics more challenging. In this paper we discuss the pinch dynamics with orbit offset, including the resulting orbit variation along a bunch, and address their relevance for the incoherent effect of the electron cloud.

WEPPR051

Issues for a Multi-bunch Operation with SPARC C-band Cavities

wakefield, HOM, linac, betatron

3042

A. Mostacci, M. Migliorati, L. Palumbo
URLS, Rome, Italy
D. Alesini, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy

SPARC C-band traveling wave cavities were originally designed for the SPARC energy upgrade in the single bunch operation mode. In the context of a gamma source based on Compton backscattering and based on the SPARC C-band technology, we investigated the issues related to the use of these structures in the multi-bunch operation mode. Several beam configurations have been considered and the effects of transverse and longitudinal long range wakefields on beam dynamics have been studied. In the paper we present the results of these studies and, in particular, the issues related to transverse beam break-up that could prevent the multi-bunch operation. Possible HOM damped structures are also proposed.

WEPPR056

Reproduction of Ceramic Chamber Impedances with Electric and Magnetic Polarities of the Ceramics

impedance, vacuum, synchrotron, proton

3051

Y. Shobuda, M. Kinsho
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In proton synchrotron, ceramic chambers are used as vacuum chambers to avoid the effect on magnetic fields from eddy current excited by the magnetic fields. One of the standard methods of the derivation of the impedances of the ceramic chamber is the field matching technique. In this report, we reproduce the formulae of the ceramic chamber impedance in terms of electric and magnetic polarities. When the beam passes through the chamber, the impedance is mainly excited by the electric polarity of the ceramic.

WEPPR060

Short range wakefields in MAX IV and FERMI Linac

wakefield, linac, cavity, electron

3063

O. Karlberg, F. Curbis, S. Thorin, S. Werin
MAX-lab, Lund, Sweden
P. Craievich, E. Ferrari, G. Penco
ELETTRA, Basovizza, Italy

Ultra-short electron pulses suffer from transverse wake fields resulting in a degradation of the beam quality. Since transverse emittance is a crucial parameter for possible FEL drivers, a careful characterization of wakefields is necessary in the design and commissioning phase of a high-brightness linear accelerator. In this paper we investigate the effect of short-range transverse wakefields in the MAXIV linac in various compression modes. Estimations of the wake potentials have been done with 3D modeling of the accelerating structures as well as with analytical models.

WEPPR066

Effects of the External Wakefield from the CLIC PETS

linac, wakefield, luminosity, emittance

3078

A. Latina, D. Schulte
CERN, Geneva, Switzerland
J. Gao, Y. Wang
IHEP, Beijing, People's Republic of China

The CLIC main linac accelerating structures will be powered by the Power Extraction and Transfer Structure (PETS) located in the drive beam decelerators. Misalignments of the PETS will excite dipolar modes in the couplers of the main linac structures that will kick the beam leading to beam quality degradation. In this paper, the impact of such dipolar kicks is studied, and tolerances, based on analytical estimations, are found both in the single- and the multi-bunch regimes. Numerical simulation obtained using the tracking code PLACET are shown to confirm the analytical estimates.

WEPPR075

Monitoring the Progress of LHC Electron-Cloud Scrubbing by Benchmarking Simulations and Pressure-Rise Observations

electron, simulation, vacuum, injection

3105

C.O. Domínguez, G. Arduini, E. Métral, G. Rumolo, F. Zimmermann
CERN, Geneva, Switzerland
G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy

Electron bombardment of a surface has been proven to reduce drastically the secondary electron yield of a material. This technique, known as scrubbing, is the ultimate solution to decrease the negative effects of an electron cloud build-up in any particle accelerator operating with intense beams. Its effectiveness has been already observed at the LHC. Since at the LHC no in-situ secondary-yield measurements are available, it has been necessary to develop a method to infer different key beam-pipe surface parameters by benchmarking simulations and pressure-rise observations. The method developed allows us to monitor the scrubbing process in order to decide on the most appropriate strategies for machine operation. In this paper we present the latest results of applying this method to the LHC in the fall of 2011 and early 2012, including data for the nominal bunch spacing of 25 ns.

WEPPR088

Modeling and Simulation of Retarding Field Analyzers at CESRTA

electron, simulation, vacuum, gun

3138

J.R. Calvey, J.A. Crittenden, G. Dugan, W. Hartung, J. Makita, M.A. Palmer
CLASSE, Ithaca, New York, USA
M.A. Furman, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the US National Science Foundation (PHY-0734867 and PHY-1002467), and Department of Energy (DE-FC02-08ER41538).
Over the course of the CESRTA program at Cornell, Retarding Field Analyzers (RFAs) have been installed in drift, dipole, quadrupole, and wiggler field regions of the CESR storage ring. RFAs are used to measure the local electron cloud flux on the vacuum chamber wall. Through the use of a retarding grid and segmented collectors, they also provide information on the energy and transverse distribution of the cloud. Understanding these measurements on a quantitative level requires the use of cloud buildup simulation codes, adapted to include a detailed model of the structure of the RFA and its interaction with the cloud. The nature of this interaction depends strongly on the strength of the local magnetic field. We have developed models for RFAs in drift and dipole regions. The drift model has been cross-checked with bench measurements, and we have compared the RFA-adapted cloud buildup simulations with data. These comparisons have then been used to obtain best fit values for the photo-emission and secondary electron emission characteristics of some of the vacuum chamber materials and cloud mitigating coatings employed at CESRTA.

THYA01

High Field Magnet Developments

quadrupole, luminosity, alignment, collider

3185

T. Nakamoto
KEK, Ibaraki, Japan

Superconducting magnets for future accelerators need to generate a field beyond 10 T. However, mature NbTi superconductors which have been already operated at its performance limit at LHC cannot be adopted. Instead, A15 type superconductors have been considered to be promising materials for the high field magnets. Especially, intensive R&D efforts for the LHC luminosity upgrade with state-of-the-art Nb3Sn superconductors have been carried out. Further future accelerators such as the High-Energy LHC and muon accelerators must require the high field reaching 20 T or more. This means that utilization of HTS (high Tc superconductors) would be the only possible solution. However, it is known that these advanced superconductors are not mechanically robust in comparison with the practical NbTi and the performance is influenced by mechanical stress and strain. In addition, magnetization effects caused by larger effective filament diameters may compromise the field quality in the accelerators. The magnet developments to overcome these issues are ongoing. This presentation will try to review the US and worldwide high field accelerator magnet developments: achievements, status, and plans.

Slides THYA01 [7.578 MB]

THXB03

Beam and Spin Dynamics in an Electric Proton EDM Ring

proton, lattice, storage-ring, quadrupole

3203

R.M. Talman
CLASSE, Ithaca, New York, USA
J. Talman
BNL, Upton, Long Island, New York, USA

Electric dipole moment (EDM) measurements may help to answer the question ‘‘Why is there more matter than anti-matter in the present universe?'' For a charged baryon like the proton such a measurement is thinkable only in a ring in which a bunch of protons is stored for more than a few minutes, with polarization ‘‘frozen'' (relative to the beam velocity) and with polarization not attenuated by decoherence. Beam and spin dynamics in an all-electric lattice with these characteristics is described. Rings for other charged baryons, such as deuterons or helium-3 nuclei, are also possible but, requiring both electric and magnetic fields, they are more complicated.

Slides THXB03 [0.155 MB]

THEPPB006

Improving the Synchrotron Performance of the Heidelberg Ionbeam Therapy Center

ion, synchrotron, controls, extraction

3243

Th. Haberer
HIT, Heidelberg, Germany

The HIT linac-synchrotron-system routinely delivers pencil beams to the dose delivering rasterscanning devices at 3 treatment rooms, including the worldwide first scanning ion gantry, and 1 experimental cave. At HIT the quality-assured library of pencil beam parameters covers roughly 100.000 combinations of the ion, energy, intensity and beam size. Each patient-specific treatment plan defines a subset of these pencil beams being subsequently requested during the dose delivery. Aiming at shortened irradiation times an upgrade program making heavy use of feed-back mechanisms is under way. Driven by patient-specific data out of the scanning beam dose delivery process central synchrotron components are coupled to the therapy control system in order to tailor the beam characteristics in real-time to the clinical requirements. The paper will discuss the functional upgrades and report about the impact on the medical application at HIT.

THPPC015

Design of a Four-vane 325 MHz RFQ Cold Model at Tsinghua University

rfq, cavity, resonance, simulation

3308

L. Du, J.C. Cai, X. Guan, Q.Z. Xing
TUB, Beijing, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (Project 11175096).
The design of a Radio Frequency Quadrupole (RFQ) accelerator cold model at Tsinghua University is presented in this paper. The 1-meter-long aluminium cold model is chosen to be the same as the low-energy part of the 3-meter-long RFQ for the Compact Pulsed Hadron Source (CPHS) project at Tsinghua University. This cold model will be used mainly for the RFQ field study and education. It will work at the RF frequency of 325 MHz. All the simulations are finished by the SUPERFISH and MAFIA codes.

THPPC020

Accurate Measurement of Ferrite Garnets to be used for Fast-tuned Ferrite Loaded Cavities in the Range of 20-40 MHz

cavity, impedance, resonance, vacuum

3317

C. Vollinger, F. Caspers
CERN, Geneva, Switzerland

For the implementation of ferrite-tuned cavities with perpendicular biased ferrites in the frequency range of 20 to 40 MHz, different types of ferrite garnets were evaluated in terms of their electromagnetic properties. We describe a precision measurement method applicable to small-sized ferrite samples of 1-square-inch surface and 2 mm thickness in the given frequency range. During measurement, these samples are exposed to varying magnetic bias fields of different orientations. Two different techniques for the determination of the real and the imaginary part of the permeability are required to achieve sufficiently accurate results. We present a detailed description of these methods as well as results obtained.

THPPC022

Enhanced Coupling Design of a Detuned Damped Structure for CLIC

wakefield, coupling, damping, simulation

3323

A. D'Elia, A. Grudiev, V.F. Khan, W. Wuensch
CERN, Geneva, Switzerland
T. Higo
KEK, Ibaraki, Japan
R.M. Jones
UMAN, Manchester, United Kingdom

The key feature of the improved coupling design in the Damped Detuned Structure (DDS) is focused on the four manifolds. Rectangular geometry slots and rectangular manifolds are used. This results in a significantly stronger coupling to the manifolds compared to the previous design. We describe the new design together with its wakefield damping properties.

THPPD007

ILSF Storage Ring Magnets

quadrupole, sextupole, 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.

THPPD008

Status of the PAL-XFEL Undulator System

undulator, controls, FEL, status

3509

D.E. Kim, H.S. Han, Y.-G. Jung, H.-G. Lee, W.W. Lee, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
J. Pflüger
European XFEL GmbH, Hamburg, Germany

Funding: Work supported by POSCO and MEST of Korea.
Pohang Accelerator Laboratory (PAL) is developing 10 GeV, 0.1 nm SASE based FEL for high power, short pulse X-ray coherent photon sources named PAL-XFEL. At the first stage PAL-XFEL needs two undulator lines for photon source. PAL is developing undulator magnetic structure based on EU-XFEL design. The hard Xray undulator features 7.2 mm min magnetic gap, and 5.0 m magnetic length with maximum effective magnetic field larger than 0.908 T to achieve 0.1nm radiation at 10 GeV electron energy. In this report, we discuss the status of the hard X-ray undulator and soft X-ray undulator designs.

THPPD009

Accelerator Magnets R&D Programme at CERN

quadrupole, permanent-magnet, linac, luminosity

3512

D. Tommasini, L. Bottura, G. De Rijk, L. Rossi
CERN, Geneva, Switzerland

The exploitation and evolution of the CERN accelerator complex pose a continuous challenge for magnet engineers. Superconducting and resistive magnets have a comparable share. The overall mass of either is approximately 50,000 tons, spread over 3 major machines (PS, SPS and LHC), two large experimental area, and a number of smaller experiments and accelerator rings. On the short term (2012-2014) the CERN plan is to upgrade its injection chain (Linac4) and experimental area (HIE-Isolde, ELENA) that require mostly a multitude of resistive magnets. The medium-term plan for the evolution of the LHC complex (2015-2021), also referred to as High-Luminosity LHC, foresees interventions on about 1 km of the machine, with magnets to be substituted with higher field, larger aperture, or both. On the long term (2025-2035) we are exploring the technological challenges of very high field magnets, at the verge of 20 T for a High Energy LHC (HE-LHC), or extremely stable high gradient quadrupoles for the Compact Linear Collider (CLIC). In this paper we provide an overview of the R&D activities addressing the various lines of development, the technology milestones, and a broad time schedule.

THPPD015

Character and Performance of Magnets for the TPS Storage Ring

sextupole, multipole, quadrupole, 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.

THPPD017

Mu2e AC Dipole 300 kHz and 5.1 MHz Tests and Comparison of Nickel-Zinc Ferrites

pick-up, proton, impedance, target

3533

L. Elementi, K.R. Bourkland, D.J. Harding, V.S. Kashikhin, A.V. Makarov, H. Pfeffer, G. Velev
Fermilab, Batavia, USA

To suppress any background events coming from the inter-bunch proton interactions during the muon transport and decay window for the Mu2e experiment, a beam extinction scheme based on two dipoles running at ~300 kHz and 5.1 MHz is considered. The effective field of these magnets is synchronized to the proton bunch spacing in such a way that the bunches are transported at the sinus nodes. Two types Ni-Zn ferrites are considered for these dipoles. Ferrites, their characteristics and ferrites selection is herein discussed through measurements performed under conditions close to operational. The excitation system and the measurement of some characteristics of the magnetic field and field shape and measurement mechanism are also presented.

THPPD018

Precision Magnet Measurements for X-band Accelerator Quadrupole Triplets

quadrupole, alignment, emittance, controls

3536

R.A. Marsh, S.G. Anderson, J.P. Armstrong
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

THPPD020

Test of a 1.8 Tesla, 400 Hz Dipole for a Muon Synchrotron

power-supply, simulation, synchrotron, acceleration

3542

D.J. Summers, L.M. Cremaldi, T.L. Hart, L.P. Perera, M. Reep
UMiss, University, Mississippi, USA
S.U. Hansen, M.L. Lopes
Fermilab, Batavia, USA
J. Reidy
Oxford High School, Mississippi, USA
H. Witte
BNL, Upton, Long Island, New York, USA

Funding: Supported by DE-FG05-91ER40622.
A 1.8 Tesla dipole magnet using 0.011" AK Steel TRAN-COR H-1 grain oriented silicon steel laminations has been constructed as a prototype for a muon synchrotron ramping at 400 Hz. Following the practice in large 3 phase transformers and our own OPERA-2D simulations, joints are mitered to take advantage of the magnetic properties of the steel which are most effective in the direction in which the steel was rolled. Measurements with a Hysteresigraph 5500 and Epstein Frame show a high magnetic permeability which minimizes stored energy in the yoke so the magnet can ramp quickly with modest voltage. A power supply with a fast IGBT switch and a polypropylene capacitor was constructed. Coils are wound with 12 gauge copper wire which will eventually be cooled with with water flowing in stainless steel tubes. The magnetic field was measured with an F. W. Bell 5180 peak sensing Hall Probe connected to a Tektronics TDS3054B oscilloscope.

THPPD021

SC Magnet Development for SIS100 at FAIR

quadrupole, sextupole, 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.

THPPD025

Expected and Measured Behaviour of the Tune in the LHC Operation at 3.5 TeV

injection, quadrupole, feedback, betatron

3554

N. Aquilina
CERN, Geneva, Switzerland

The tune of the Large Hadron Collider depends on the strength of the quadrupole magnets, the b2 component in the main dipoles plus the b3 component in the main dipoles and the sextupolar correctors via feed down in case of systematic misalignment. The magnetic model of the machine, based on a fit of magnetic measurements, has an intrinsic precision which can be estimated in a few units. During the first years of operation of the LHC, tune has been routinely measured and corrected through a feedback system. In this paper we reconstruct from the beam measurements and the settings of the feedback loop the evolution of tune during injection, ramp, and squeeze. This gives the obtained precision of the magnetic model of the machine with respect to quadrupolar and sextupolar components. At the injection plateau there is an unexpected large decay whose origin is not understood: we present the data, with the time constants and the dependence on the previous cycles, and compare to the magnetic measurements. During the ramp the tune drifts by about 0.05: this precision is related to the precision in tracking the quadrupolar field in the machine.

THPPD026

Splice Resistance Measurements in the LHC Main Superconducting Magnet Circuits by the New Quench Protection System

monitoring, background, injection, controls

3557

Z. Charifoulline, K. Dahlerup-Petersen, R. Denz, A.P. Siemko, J. Steckert
CERN, Geneva, Switzerland

The interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting cables stabilized by a copper bus bar. After the 2008 LHC incident, caused by a defective interconnection, a new layer of high resolution magnet circuit quench protection (nQPS) has been developed and integrated with the existing systems. It allowed mapping of the resistances of all superconducting splices during the 2009 commissioning campaign. Since April 2010, when the LHC was successfully restarted at 3.5TeV, every bus bar interconnection is constantly monitored by the nQPS electronics. The acquired data are saved to the LHC Logging Database. The paper will briefly describe the data analysis method and will present the results from the two years of resistance measurements. Although no splice was found with resistance higher than 3.3nOhm and no significant degradation in time was observed so far, the monitoring of splices will stay active till the end of LHC 3.5TeV run. The detected outliers will be repaired during the Splice Consolidation Campaign in 2013-2014.

THPPD027

Consolidation of the 13 kA Splices in the Electrical Feedboxes of the LHC

quadrupole, controls, cryogenics, superconducting-magnet

3560

A. Perin, S. Atieh, O. Pirotte, R. Principe, D. Ramos, F. Savary, C.E. Scheuerlein, J.Ph. G. L. Tock, A.P. Verweij
CERN, Geneva, Switzerland

In 2008 a defective connection in one of the 13 kA dipole circuits of the LHC caused an electric breakdown that resulted in extensive damage in a sector of the accelerator. The investigation performed after the accident showed the necessity to consolidate the electrical splices of the 13 kA dipole and quadrupole circuits in order to operate the LHC at its nominal energy of 7 TeV. These circuits are powered through electrical feedboxes located at each end of the 8 sectors of LHC. In the feedboxes the current is routed from room temperature to the superconducting magnets along current leads and superconducting busbars and flows through at least two internal splices. These splices are based on the same technologies as the magnet to magnet ones but they are significantly different in terms of environment and configuration. As for the magnet to magnet splices, a consolidation will be necessary to operate them at nominal current. This paper presents an analysis of the properties of these splices and the technologies that will be used to consolidate them. The quality control provisions and the workflow to perform this operation during the first long shutdown of LHC are also presented.

THPPD028

Studies on the LHC Superconducting Circuits and Routine Qualification of Their Functionalities

cryogenics, collider, hadron, target

3563

M. Pojer, G. D'Angelo, R. Mompo, R. Schmidt, M. Solfaroli Camillocci
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) is systematically undergoing periods of maintenance stop (either 4-5 days stops or longer Christmas breaks), after which some of the superconducting circuits (or the totality of them) have to be re-commissioned to check the correct functionality of all powering and protection systems. Detailed procedures have been developed during the past few years and they have been optimized to increase powering tests efficiency, thus reducing beam downtime. The approach to the routine qualification of the LHC powering systems is described in this paper. During 2011 technical stops, some particular studies on the superconducting circuits were performed, to assess the quality of the superconducting splices of individually powered magnets and to study the quench propagation in the main magnet bus-bars. The methodology of these tests and some results are also presented.

THPPD031

Measurement of the Residual Resistivity Ratio of the Bus Bars Copper Stabilizer of the 13 kA Circuits of the LHC

quadrupole, instrumentation, simulation, factory

3572

A. Apollonio, S.D. Claudet, M. Koratzinos, R. Schmidt, A.P. Siemko, M. Solfaroli Camillocci, J. Steckert, H. Thiesen, A.P. Verweij
CERN, Geneva, Switzerland

After the incident of September 2008, the operational beam energy of the LHC has been set to 3.5 TeV, since not all joints of the superconducting busbars between magnets have the required quality for 7 TeV operation. This choice is based on simulations to determine the safe current in the main dipole and quadrupole magnets, reproducing the thermal behavior of a quenched superconducting joint by taking into account all relevant factors that affect a possible thermal runaway. One important parameter of the simulation is the RRR (Residual Resistivity Ratio) of the copper stabilizer of the busbar connecting superconducting magnets. A dedicated campaign to measure this quantity for the main 13kA circuits of the LHC on all sectors was performed during the Christmas stop in December 2010 and January 2011. The measurement method as well as the data analysis and results are presented in this paper.

THPPD032

Consolidation of the LHC Superconducting Circuits: A Major Step towards 14 TeV Collisions

superconducting-magnet, quadrupole, controls, vacuum

3575

J.Ph. G. L. Tock, F.F. Bertinelli, F. Bordry, P. Fessia, R. Ostojic, A. Perin, H. Prin, F. Savary, C.E. Scheuerlein, H.H.J. Ten Kate, A.P. Verweij, G.P. Willering
CERN, Geneva, Switzerland

Following the incident in one of the main dipole circuits of the Large Hadron Collider (LHC) in September 2008, a detailed analysis of all magnet circuits has been performed by a dedicated task force. This analysis has revealed several critical issues in the design of the 13 kA splices between the main LHC cryomagnets. These splices have to be consolidated before increasing the beam energy above 4 TeV and to operate the LHC close to 7 TeV per beam. The design for the consolidated 13 kA splices is now complete and has been reviewed by an international committee of experts. In the process, all types of superconducting circuits have been thoroughly screened and several important recommendations were established. They were critically assessed and the resulting actions are presented. In addition to the work on the 13 kA splices, other interventions will be performed during the first long shut-down of the LHC to consolidate globally all the superconducting circuits. The associated quality controls have been defined and are detailed in the operations workflow. The schedule constraints, repairs production rate, available space and resources are presented as well.

THPPD033

Using Permanent Magnets to Boost the Dipole Field for the High-energy LHC

permanent-magnet, cryogenics, background, radiation

3578

F. Zimmermann
CERN, Geneva, Switzerland
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan

Funding: Work supported by the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579.
The High-Energy LHC (HE-LHC) will be a new accelerator in the LHC tunnel based on novel dipole magnets, with a field up to 20 T, which are proposed to be realized by a hybrid-coil design, comprising blocks made from Nb-Ti, Nb3Sn and HTS, respectively. Without the HTS the field would be only 15 T. In this note we propose and study the possibility of replacing the inner HTS layer by (weaker) permanent magnets that might contribute a field of 1-2 T, so that the final field would reach 16-17 T. Advantages would be the lower price of permanent magnets compared with HTS magnets and their availability.

THPPD034

Quench Performance and Field Quality of 90-mm Nb3Sn Quadrupoles of TQC Series

quadrupole, collider, controls, alignment

3581

G. Chlachidze, N. Andreev, R. Bossert, J. DiMarco, V. Kashikhin, M.J. Lamm, A. Nobrega, I. Novitski, M.A. Tartaglia, G. Velev, 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
A series of accelerator quality Nb3Sn quadrupole models has been developed, fabricated and tested at Fermilab. The magnet design includes a 90 mm aperture surrounded by four two-layer Nb3Sn coils supported by a stainless steel collar, iron yoke and stainless steel skin. This paper describes the design and fabrication features of the quadrupole models and presents the summary of model tests including quench performance and field quality at 4.5 and 1.9 K.

THPPD035

Magnets for Interaction Regions of a 1.5×1.5 TeV Muon Collider

quadrupole, collider, background, luminosity

3584

V. Kashikhin, Y. Alexahin, N.V. Mokhov, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The updated IR optics and conceptual designs of large aperture superconducting quadrupole magnets for a muon collider with a c.o.m. energy of 3 TeV and an average luminosity of 4·10³⁴ cm^-2 s^-1 are presented. All magnets are based on the Nb3Sn superconductor and designed to provide an adequate operation field gradient in the given aperture with the critical current margin required for reliable machine operation. Special dipole coils were added to quadrupole designs to provide ~2 T bending field and thus facilitate chromaticity correction and dilute decay electron fluxes on the detector. Magnet cross-sections were optimized to achieve the best possible field quality in the magnet aperture occupied with beams. Magnet parameters are reported and compared with the requirements. Energy deposition calculations with the MARS code have allowed to optimize parameters of inner absorbers, collimators in interconnect regions and Machine-Detector Interface.

THPPD036

High-Field Combined-Function Magnets for a 1.5×1.5 TeV Muon Collider Storage Ring

quadrupole, collider, magnet-design, lattice

3587

V. Kashikhin, Y. Alexahin, N.V. Mokhov, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
A new storage ring lattice based on combined function high-field magnets and conceptual designs of superconducting magnets with dipole and quadrupole coils for a muon collider with a c.o.m. energy of 3 TeV and an average luminosity of 4x10³⁴ cm^-2 s^-1 are presented. Magnets are designed to provide the required focusing field gradient and bending field in the aperture with the appropriate operation margin. Magnets have large apertures to provide an adequate space for internal absorbers, vacuum insulation, beam pipe, and helium channel. Coil cross-sections were optimized to achieve the best possible field quality in the magnet aperture occupied with beams. Magnet parameters are reported and compared with the requirements. Energy deposition calculations with the MARS code have allowed to optimize parameters of inner absorbers and collimators in interconnect regions, thus reducing peak power density and dynamic loads to the tolerable levels.

THPPD037

Design Studies of a Dipole with Elliptical Aperture for the Muon Collider Storage Ring

collider, quadrupole, storage-ring, electron

3590

M.L. Lopes, V. Kashikhin, J.C. Tompkins, A.V. Zlobin
Fermilab, Batavia, USA
R.B. Palmer
BNL, Upton, Long Island, New York, USA

Funding: Work supported partially by US-MAP and by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The requirements and operating conditions for superconducting magnets used in a Muon Collider Storage Ring are challenging. About one third of the beam energy is deposited along the magnets by the decay electrons. As a possible solution an elliptical tungsten absorber could intercept the decay electrons and absorb the heat limiting the heat load on superconducting coils to the acceptable level. In this paper we describe the main design issues of dipoles with an elliptical aperture taking into consideration the field and field quality. The temperature margin and the forces in the coils are presented as well.

THPPD038

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

quadrupole, injection, sextupole, 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

injection, simulation, sextupole, 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.

THPPD040

Quench Protection Analysis of a Single-Aperture 11T Nb3Sn Demonstrator Dipole for LHC Upgrades

simulation, luminosity, quadrupole, status

3599

A.V. Zlobin, I. Novitski, R. Yamada
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 by 2014 a 5.5-m-long twin-aperture dipole prototype suitable for installation in the LHC. 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 summarizes the results of quench protection analysis of the single-aperture Nb3Sn demonstrator dipole for the LHC collimation system upgrade.

THPPD042

High Radiation Environment Nuclear Fragment Separator Dipole Magnet

radiation, quadrupole, magnet-design, target

3605

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

Funding: Supported in part by STTR Grant 4746 · 11SC06273
Magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) would be subjected to extremely high radiation and heat loads. Critical elements of FRIB are the dipole magnets which select the desired isotopes. Since conventional NiTi and Nb3Sn superconductors must operate at ~4.5 K, the removal of the high heat load generated in these magnets with these superconductors would be difficult. The coils for these magnets must accommodate the large curvature from the 30° bend that the magnets subtend. High temperature superconductor (HTS) have been shown to be radiation resistant and can operate in the 20-50 K temperature range where heat removal is an order of magnitude more efficient than at 4.5 K. Furthermore these dipole magnets must be removable remotely for servicing because of the extremely high radiation environment. This paper will describe the magnetic and conceptual design of these magnets.

THPPD044

Fabrication and Testing of Curved Test Coil for FRIB Fragment Separator Dipole

radiation, FEL, quadrupole, proton

3611

S.A. Kahn
Muons, Inc, Batavia, USA
J. Escallier, R.C. Gupta, G. Jochen, Y. Shiroyanagi
BNL, Upton, Long Island, New York, USA

Funding: Supported in part by SBIR Grant 4746 · 11SC06273
A critical element of the fragment separator region of the Facility for Rare Isotope Beams (FRIB) is the 30° dipole bend magnet. Because this magnet will be subjected to extremely high radiation and heat loads, operation at 4.5 K would not be possible. High temperature superconductors which have been shown to be radiation resistant and can operated in the 30-50 K temperature range which is more effective for heat removal. An efficient design for this magnet would make use of coils that follow the curvature of the magnet. Winding curved coils with negative curvature are difficult as the coil tends to unwind during the process. As part of an R&D effort for this magnet we are winding a ¼ scale test coil for this magnet with YBCO conductor and are testing it at 77 K. This paper will discuss the winding process and the test results of this study.

THPPD050

Fast Ramping Arbitrary Waveform Power Supplies for Correction Coils in a Circular Electron Accelerator

electron, controls, power-supply, resonance

3623

A. Dieckmann, A. Balling, O. Boldt, F. Frommberger, W. Hillert, W. Lindenberg
ELSA, Bonn, Germany

New fast ramping power supplies working in pulsed bridge technology upgrade the existing Corrector System at ELSA. Current changes of ±0.8 A/msec are achieved. The newly developed CAN-Bus Interface allows linear interpolation of up to 250 support points with minimal time steps of 1msec. The first stage uses 24 power supplies to improve the position of the beam orbit in the horizontal plane using dipole correction coils. It will be extended to include the vertical plane with new corrector coils in the near future. This poster describes the operating principles of the power supply and the interface.

THPPD054

Low Current Bipolar Magnet Power Supply System at the PLS-II Storage Ring

quadrupole, lattice, EPICS, power-supply

3635

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. Low current bipolar MPSs for vertical corrector(VC), horizontal corrector(HC), fast corrector(FC), aux.-quadrupole(AQ), skew(SK) and dipole trim coil(TR) magnets are H-bridge type. All MPSs are performed less than ± 10 ppm output current stability and adopted full digital controller. Except vertical corrector MPSs, all unipolar and bipolar MPSs are developed as embedded EPICS IOC. In this paper, we report on the development and characteristics of the bipolar MPS for the PLS-II Storage Ring.

THPPP023

Momentum Cogging at the Fermilab Booster

booster, injection, controls, extraction

3782

K. Seiya, C.C. Drennan, W. Pellico, A.K. Triplett, A.M. Waller
Fermilab, Batavia, USA

The Fermilab booster has an intensity upgrade plan called the Proton Improvement plan (PIP). The flux throughput goal is 2·10¹⁷ protons/hour which is almost double the current operation at 1.10¹⁷ protons/hour. The beam loss in the machine is going to be an issue. The booster accelerates beam from 400 MeV to 8GeV and extracts to The Main Injector (MI). Cogging is the process that synchronizes the extraction kicker gap to the MI by changing radial position of the beam during the cycle. The gap creation occurs at about 700MeV which is 6msec into the cycle. The variation of the revolution frequency from cycle to cycle is larger at lower energy and it is hard to control by changing the radial position because of aperture limitations. Momentum cogging is able to move the gap creation earlier by using dipole correctors and radial position feedback, and controlling the revolution frequency and radial position at the same time. The new cogging is going to save energy loss and aperture. The progress of the momentum cogging system development is going to be discussed in this paper.

THPPP027

The Design of a Large Booster Ring for the Medium Energy Electron-Ion Collider at JLab

booster, ion, collider, electron

3791

E.W. Nissen, T. Satogata, Y. Zhang
JLAB, Newport News, Virginia, USA

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In this paper, we present the current design of the large booster ring for the Medium Energy Electron-Ion Collder (MEIC) at JLab. The booster ring takes 3 GeV protons or ions of equivalent energy from a pre-booster ring, and accelerates them to 20 GeV for protons or equivalent energy for light to heavy ions before sending them to the ion collider ring. The present design calls for a figure-8 shape of the ring for superior preservation of ion polarization. The ring is made of warm magnets and shares a tunnel with the two collider rings. Acceleration is achieved by warm RF systems. A linear optics has been designed with the transition energy above the highest beam energy in the ring so crossing of transition energy will be avoided. Preliminary beam dynamics studies including chromaticity compensation, analyses of dynamic aperture, working point and high order effects are also presented in this paper.

THPPP037

Status of the 325 MHz 4-ROD RFQ

simulation, rfq, HOM, linac

3815

B. Koubek, A. Schempp, J.S. Schmidt
IAP, Frankfurt am Main, Germany
L. Groening
GSI, Darmstadt, Germany

For the FAIR project of GSI as part of the proton linac, a 325 MHz 4-ROD RFQ with an output energy of 3 MeV is planned. Due to the simulations regarding the RF design, a prototype of this RFQ was built. Measurements with this prototype to verify the simulation results have been done. In addition, simulations with increasing cell numbers and simulations concerning the boundary fields of the electrodes are presented in this paper.

THPPP042

The First Step of RFQ Development in KBSI

rfq, ion, quadrupole, emittance

3829

J.W. Ok, S. Choi, B.C. Kim, B.S. Lee, J.Y. Park, M. Won, J.H. Yoon
Korea Basic Science Institute, Busan, Republic of Korea

The RFQ for accelerating an ion beam is being developed in Korea Basic Science Institute (KBSI). The KBSI RFQ is designed to accelerate 1 mA lithium beam (Q/A=3/7) at 88 MHz. It is considered to be a 4-vane RFQ structure. The injection beam energy into RFQ is 12 keV/u, the output beam energy downstream from RFQ is 300 keV/u. The RFQ has to show stable operation, meet availability, and have the minimum losses so as to guarantee the best performance/cost ratio. At the first step, two dimensional geometry structure was studied using SUPERFISH code for the resonance frequency of quadrupole and dipole modes. Three dimensional field distributions were investigated by CST microwave studio. The beam dynamics in RFQ accelerator were studied using PARMTEQM code. Based on these results, the structural analysis should be studied and a cold model will be fabricated and investigated. The practical KBSI RFQ will be manufactured in next year.

THPPP064

Project X RFQ EM Design

rfq, simulation, quadrupole, radio-frequency

3883

G.V. Romanov
Fermilab, Batavia, USA
M.D. Hoff, D. Li, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA

Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory (FNAL). The Project X front-end would consist of an H⁻ ion source, a low-energy beam transport (LEBT), a cw 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, and a medium-energy beam transport (MEBT). Lawrence Berkeley National Laboratory (LBNL) and FNAL collaboration is currently developing the designs for various components in the Project X front end. This paper reports the detailed EM design of the cw 162.5 MHz RFQ that provides bunching of the 1-10 mA H⁻ beam with acceleration from 30 keV to 2.1 MeV.

THPPP074

Chopping High Intensity Proton Beams Using a Pulsed Wien Filter

focusing, proton, beam-transport, emittance

3907

C. Wiesner, L.P. Chau, H. Dinter, M. Droba, O. Meusel, I. Müller, D. Noll, U. Ratzinger
IAP, Frankfurt am Main, Germany

Chopping high intensity beams at low energies poses substantial challenges. A novel ExB chopper system for proton beams of up to 200 mA at energies of 120 keV is being developed for the accelerator driven neutron source FRANZ*. It uses a Wien filter-type ExB configuration consisting of a static magnetic deflection field and a pulsed electric compensation field to deliver 100 ns beam pulses. The setup minimizes the risk of voltage breakdowns and provides secure beam dumping outside the transport line. In order to prevent beam aberrations and emittance growth careful matching of electric and magnetic deflection forces is required. Detailed numerical studies for the field design and their effects on beam transport were conducted. An H-type dipole magnet with special transverse and longitudinal pole contours was manufactured and combined with shielding tubes to shape the magnetic field. The electric field is driven by a HV pulse generator providing ±6 kV at a repetition rate of 250 kHz. Accurate layout of the deflector plates is required in order to tackle the issues of field quality, cooling and spark prevention. Transport simulations and beam deflection experiments are presented.
* U. Ratzinger et al., "The Driver Linac of the Neutron Source FRANZ," Proc. of IPAC2011, WEPS040, P. 2577 (2011).

THPPR052

The MedAustron Proton Gantry

optics, quadrupole, proton, synchrotron

4091

A. Koschik
PSI, Villigen, Switzerland
U. Dorda, A. Koschik
EBG MedAustron, Wr. Neustadt, Austria
D. Meer, E.S. Pedroni
Paul Scherrer Institut, Villigen, Switzerland

The MedAustron project realizes a synchrotron based accelerator facility in Austria for cancer treatment with protons and carbon ions, currently in the construction phase. In order to allow full patient treatment flexibility, one of the four treatment rooms will be equipped with a proton gantry. While its hardware design is a copy of the PSI Gantry 2, different constraints on the beam optics must be accounted for as MedAustron uses a synchrotron as particle accelerator and a rotator to match the beam into the rotated frame, as compared to the cyclotron of the PSI PROSCAN facility. This paper presents the current status of the hardware design and procurement and a review of the design characteristics of the PSI Gantry 2 for the MedAustron case. In particular the stability of the beam parameters during beam scanning over the treatment scan area is investigated in detail. To achieve utmost parallel active scanning performance, the magnet design parameters (edge angles, corrector quadrupole, tapered dipole) have been optimized for PSI Gantry 2. Equivalent studies are undertaken for the MedAustron requirements and constraints in this paper.

THPPR054

Progress in the Design of a Curved Superconducting Dipole for a Therapy Gantry

proton, target, solenoid, ion

4097

S. Caspi, D. Arbelaez, L.N. Brouwer, D.R. Dietderich, R.R. Hafalia, D. Robin, A. Sessler, C. Sun, W. Wan
LBNL, Berkeley, California, USA

A curved superconducting magnet for a carbon therapy gantry requires a large bore and a field around 5T. The design reduces the gantry’s size and weight and makes it more comparable with gantries used for proton therapy. In this paper we report on a combined function superconducting dipole magnet that is half the size needed for carbon gantry and is about the size of a proton gantry. The half scale, with a 130 mm bore diameter that is curved 90 degrees at a radius of 634 mm, superimposes two layers of oppositely wound and skewed solenoids that are energized in a way that nulls the solenoid field and doubles the dipole field. Furthermore, the combined architecture of the windings can create a selection of field terms that are off the near-pure dipole field. In this paper we report on the design of a two layers curved coil and the production of the winding mandrel. Some details on the magnet assembly are included.

FRXAB01

Symplectic Tracking and Compensation of Dynamic Field Integrals in Complex Undulator Structures

undulator, permanent-magnet, simulation, polarization

4165

J. Bahrdt, G. Wüstefeld
HZB, Berlin, Germany

This presentation covers analytical models that describe the interaction of an electron beam with the magnetic field of undulators. Analytic approximations to the Hamilton-Jacobi equation yield generating functions useful for particle tracking and therefore efficient simulation. Analytic expressions for kick maps of APPLE II undulators are presented as well. Passive and active shimming schemes including magic fingers and current sheets are also modeled. Applications at BESSY II are discussed which ensure efficient injection during top-up to satisfy machine protection and radiation safety requirements.

Slides FRXAB01 [1.922 MB]