IPAC2012 - List of Keywords (betatron)

Paper	Title	Other Keywords	Page
MOYCP01	Design and Simulation of IOTA - a Novel Concept of Integrable Optics Test Accelerator	electron, focusing, optics, simulation	16
	S. Nagaitsev, A. Valishev Fermilab, Batavia, USA V.V. Danilov ORNL, Oak Ridge, Tennessee, USA D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	The use of nonlinear lattices with large betatron tune spreads can increase instability and space charge thresholds due to improved Landau damping. Unfortunately, the majority of nonlinear accelerator lattices turn out to be nonintegrable, producing chaotic motion and a complex network of stable and unstable resonances. Recent advances in finding the integrable nonlinear accelerator lattices have led to a proposal to construct at Fermilab a test accelerator with strong nonlinear focusing which avoids resonances and chaotic particle motion. This presentation will outline the main challenges, theoretical design solutions and construction status of the Integrable Optics Test Accelerator underway at Fermilab.
	Slides MOYCP01 [2.816 MB]

MOEPPB007	Studies of eRHIC Coherent Instabilities	proton, simulation, impedance, space-charge	91
	G. Wang, M. Blaskiewicz BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In the presence of an effective coherent electron cooling, the rms ion bunch length in eRHIC will be kept at 8.4cm, which is about a factor of 3 shorter than the current RHIC rms bunch length. Together with a factor of 2 increase in bunch intensity, coherent instabilities could be a potential limitation for achieving desired machine performance. In this study, we use the tracking code TRANFT to find thresholds and growth rates for various single bunch and coupled bunch instabilities with linear chromaticity and amplitude dependent tune shift taken into account. Based on the simulation results, requirements of machine parameters such as rf voltage, linear chromaticity, and octupole strength are specified to avoid these instabilities.

MOEPPB015	Excitation of Intra-bunch Vertical Motion in the SPS - Implications for Feedback Control of Ecloud and TMCI Instabilities	resonance, pick-up, feedback, synchrotron	112
	J.D. Fox, J.M. Cesaratto, M.T.F. Pivi, C.H. Rivetta, O. Turgut, S. Uemura SLAC, Menlo Park, California, USA W. Höfle, U. Wehrle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP). Electron cloud and transverse mode coupled-bunch instabilities (TMCI) limit the bunch intensity in the CERN SPS. Intra-bunch fast feedback systems are a possible method to control these effects. This paper presents experimental measurements of single-bunch motion in the SPS driven by a GHz bandwidth vertical excitation system. The primary goal is to quantify the change in internal bunch dynamics as instability thresholds are approached, and quantify the frequencies of internal modes as Ecloud effects become significant. The beam response is sampled at 20 GS/sec. in response to arbitrary excitation patterns, with data in 2011 taken at 3 bunch intensities. We show the excitation of barycentric, head-tail and higher vertical modes. The beam motion is analyzed in the time domain, via animated presentations of the sampled vertical signals, and in the frequency domain, via spectrograms showing the modal frequencies vs. time. The demonstration of the excitation of selected internal modes is a significant step in development of the feedback control techniques. "A 4 GS/Sec. Synchronized Vertical Excitation System for SPS Studies - Steps Towards Wideband Feedback," these proceedings.

MOPPC003	Very Fast LHC Crab Cavity Failures and their Mitigation	luminosity, simulation, cavity, optics	121
	T. Baer, R. Calaga, R. De Maria, S.D. Fartoukh, E. Jensen, R. Tomás, J. Tückmantel, J. Wenninger, B. Yee-Rendon, F. Zimmermann CERN, Geneva, Switzerland T. Baer University of Hamburg, Hamburg, Germany
	For the high-luminosity LHC upgrade program (HL-LHC), the installation of crab cavities (CCs) is needed to compensate the geometric luminosity loss due to the crossing angle and for luminosity leveling []. The baseline is a local scheme with CCs around the ATLAS and CMS experiments. In a failure case (e.g. a control failure or arcing in the coupler), the voltage and/or phase of a CC can change significantly with a very fast time constant of the order of 1 to 10 LHC turns. This can lead to large, global betatron oscillations of the beam. The impact of CC failures on the beam dynamics is discussed and the results from dedicated simulations are presented. Mitigation strategies to limit the impact of CC failures to an acceptable level are proposed. F. Zimmermann and O. Brüning, “Parameter Space for the LHC High-Luminosity Upgrade”, IPAC'12, MOPPC005, May 2012.

MOPPC021	Explore the Possibility of Accelerating Polarized He-3 Beam in RHIC	resonance, proton, closed-orbit, neutron	172
	M. Bai, E.D. Courant, W. Fischer, V. Ptitsyn, 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. As the world’s first high energy polarized proton collider, RHIC has made significant progress in measuring the proton spin structure in the past decade. In order to have better understanding of the contribution of up and down quarks to the proton spin structure, collisions of high energy polarized neutron beams are required. In this paper, we present studies of accelerating polarized Helium-3 in RHIC with the current dual snake configuration. The possibilities of adding two more pairs of snakes for accelerating polarized He-3 were explored. Results of a six snake configuration in RHIC are also reported in the paper.

MOPPC027	Synchro-Betatron Effects in the Presence of Large Piwinski Angle and Crab Cavities at the HL-LHC	luminosity, simulation, coupling, damping	190
	S.M. White BNL, Upton, Long Island, New York, USA R. Calaga CERN, Geneva, Switzerland R. Miyamoto ESS, Lund, Sweden
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). The reduction of beta-star at the collision points for the high luminosity LHC (HL-LHC) requires an increment in the crossing angle to maintain the normalized beam separation to suppress the effects of long-range beam-beam interactions. However, increase in crossing angle may give rise to synchro-betatron resonances which may negatively affect the beam emittance and lifetime. 6D weak-strong and strong-strong simulations are performed to study the effect of synchro-betatron resonances in the context of the HL-LHC layout and its suppression via crab crossing.

MOPPC032	Injection and Broadband Matching for the PRISM Muon FFAG	injection, solenoid, target, dipole	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.

MOPPC076	New Features of the Parallel TRACY for Nonlinear Beam Dynamics	lattice, dynamic-aperture, sextupole, closed-orbit	310
	M.-S. Chiu, H.-P. Chang NSRRC, Hsinchu, Taiwan
	The TRACY code is used to analyze and simulate the nonlinear beam dynamics of the designed lattice. To speed up the lattice design flow, we parallelized the TRACY by MPI and developed a GUI by GTK+ to integrate the functions of TRACY and added a function of nonlinear optimization adapted from OPA, which is used to optimize the nonlinear driving terms by powell algorithm. The GUI is used for parameter input and data visualization. The procedures of nonlinear optimization and beam dynamics analysis are integrated and streamlined. Users do not need to write and compile the code any more. The results will be demonstrated in this report.

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

MOPPD011	Analysis of Frequency Spectrum of Bunched Beam Related to Transverse Laser Cooling*	synchrotron, laser, coupling, ion	391
	K. Jimbo Kyoto University, Institute for Advanced Energy, Kyoto, Japan Z.Q. He TUB, Beijing, People's Republic of China M. Nakao, A. Noda, H. Souda, H. Tongu Kyoto ICR, Uji, Kyoto, Japan
	Using synchro-betatron coupling, transverse laser cooling is pursued at an ion storage/cooler ring, S-LSR, Kyoto University. A bunched 40 keV 24Mg+ beam was cooled by a co-propagating laser of 280 nm wavelength. Synchrotron oscillation in the longitudinal direction and betatron oscillation in the horizontal direction were intentionally coupled by an RF drift tube located at the finite dispersive section (D =1.1 m) where longitudinal cooling force was transmitted to the horizontal direction.* Analyzing bunched Schottky signals, which represents longitudinal physical quantities of the beam, we try to obtain an evidence of synchro-betatron coupling and accordingly laser cooling of the beam in the transverse direction. * H. Okamoto, Phys. Rev. E 50, 4982 (1994)

MOPPD012	Challenge for More Efficient Transverse Laser Cooling for Beam Crystallization	laser, synchrotron, ion, simulation	394
	A. Noda, M. Nakao, H. Souda, H. Tongu Kyoto ICR, Uji, Kyoto, Japan M. Grieser MPI-K, Heidelberg, Germany Z.Q. He TUB, Beijing, People's Republic of China K. Ito, H. Okamoto, K. Osaki HU/AdSM, Higashi-Hiroshima, Japan K. Jimbo Kyoto University, Institute for Advanced Energy, Kyoto, Japan Y. Yuri JAEA/TARRI, Gunma-ken, Japan
	Funding: Work supported by Advanced Compact Accelerator Development project by MEXT. Also supported by GCOE project at Kyoto University, The next generation of Physics-Spun from Universality and Emergency. At S-LSR in ICR, Kyoto University, Mg ion beam has been successfully laser cooled both in longitudinal* and transverse** directions. The cooling rate, however, is not strong enough to realize the crystalline beam due to the heating because of intra-beam scattering (IBS) effect. So as to suppress this IBS, reduction of the beam intensity is inevitable, which however, had resulted in poor S/N ratio for observation of the transverse beam size. In the present paper, we would like to describe a new beam scraping scheme, which selects out the beams in the distribution tail of the transverse phase space keeping the beam density in the core part by simultaneous application of multi-dimensional laser cooling and beam scraping. The strategy to reduce the beam intensity and hence beam heating due to IBS by a controlled scraping of the outskirt beam keeping the beam density at core part almost the same, has been searched by combination of the beam experiments and computer simulations. * M. Tanabe et al., Applied Physics Express 1, 028001 (2008). ** M. Nakao et al., submitted to PRST-AB.

MOPPD013	Observation of 2-Component Bunched Beam Signal with Laser Cooling	laser, ion, coupling, injection	397
	H. Souda, M. Nakao, A. Noda, H. Tongu Kyoto ICR, Uji, Kyoto, Japan M. Grieser MPI-K, Heidelberg, Germany Z.Q. He TUB, Beijing, People's Republic of China K. Ito, H. Okamoto HU/AdSM, Higashi-Hiroshima, Japan K. Jimbo Kyoto University, Institute for Advanced Energy, Kyoto, Japan Y. Yuri JAEA/TARRI, Gunma-ken, Japan
	Funding: Work supported by Advanced Compact Accelerator Development Project of MEXT, Global COE program "The Next Generation of Physics, Spun from Universality and Emergence" and Grant-in-Aid for JSPS Fellows. Longitudinal beam temperature during a laser cooling was measured through bunch length measurement at S-LSR. 40keV 24Mg+ beams were bunched by an RF voltage with a harmonic number of 5 and were cooled by a co-propagating laser with a wavelength of 280nm. Bunch length was measured by time-domain signal from a pair of parallel-plate electrostatic pickups with a length of 140mm. Injected non-cooled beams gave a bunch length of 2.5m (2-σ) and cooled beam has a 2-component of broad and sharp distribution. Broad distribution had a longitudinal length of 2.2m, which is close to that of initial beam. The length of the sharp distribution shrunk to 0.25m and is considered as a cooled part. Capture efficiency of cooling, which represents the ratio of the particle numbers of cooled part and the total particle number, varies by the change of the detuning of the laser (fixed frequency or scanning). With scanning range of 2GHz, capture efficiency was improved from 66% to 92%, whereas the bunch became longer by 10% with scanning. Approach to improve the number of cooled particle and cut uncooled part* will be applied to attain a strong signal with a low-current beam with a low temperature. * J. S. Hangst et al., Phys. Rev. Lett. 74, 4432 (1995). ** A. Noda et al., these proceedings.

MOPPD067	Novel Slow Extraction Scheme for Proton Accelerators Using Pulsed Dipole Correctors and Crystals	extraction, septum, proton, scattering	517
	V.D. Shiltsev Fermilab, Batavia, USA
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359 Slow extraction of protons beams from circular accelerators is currently widely used for a variety of beam-based experiments. The method has some deficiencies including limited efficiency of extraction, radiation induced due to scattering on the electrostatic septa and limited beam pipe aperture, beam dynamics effects of space charge forces and magnet power supplies ripple. Here we present a novel slow extraction scheme employing a number of non-standard accelerator elements, such as Silicone crystal strips and pulsed strip-line dipole correctors, and illustrate practicality of these examples at the 8 GeV proton Recycler Ring at Fermilab.

MOPPD077	Studies for an Alternative LHC Non-Linear Collimation System	collimation, proton, sextupole, impedance	544
	L. Lari, R.W. Assmann, V. Boccone, F. Cerutti, A. Mereghetti, R. Versaci, V. Vlachoudis CERN, Geneva, Switzerland A. Faus-Golfe, L. Lari, J. Resta-López IFIC, Valencia, Spain
	Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program. A LHC nonlinear Betatron cleaning collimation system would allow larger gap for the mechanical jaws, reducing as a consequence the collimator-induced impedance, which may limit the LHC beam intensity. In this paper, the performance of the proposed system is analyzed in terms of beam losses distribution around the LHC ring and cleaning efficiency in stable physics condition at 7TeV for Beam1. Moreover, the energy deposition distribution on the machine elements is compared to the present LHC Betatron cleaning collimation system in the Point 7 Insertion Region (IR).

MOPPD078	Accelerator Physics Study on the Effects from an Asynchronous Beam Dump in the LHC Experimental Region Collimators	proton, simulation, kicker, optics	547
	L. Lari, R.W. Assmann, V. Boccone, R. Bruce, F. Cerutti, A. Mereghetti, A. Rossi, V. Vlachoudis CERN, Geneva, Switzerland A. Faus-Golfe, L. Lari IFIC, Valencia, Spain
	Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program. Asynchronous beam aborts at the LHC are to be expected once per year. Accelerator physics studies of asynchronous dumps have been performed at different beam energies and beta-stars. The loss patterns are analyzed in order to identify the losses in particular on the Phase 1 Tertiary Collimators (TCT), since their Tungsten jaw insert has a low damage threshold with respect to the loss load expected. Settings for the tilt angle of the TCTs are discussed with the aim of reducing the thermal loads on the TCT themselves.

MOPPR030	Various Methods to Measure the Betatron Tune of the Synchrotoron	closed-orbit, pick-up, synchrotron, injection	843
	S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	Generally in the synchrotron, the frequency of transverse oscillation of the bunched beam for each single turn (usually called betatron tune or just "tune") is one of fundamental controllable knobs to avoid the instability of the accelerator. In this report, it is not mentioned about the effect to the beam instability but it is focused to various methods to measure the betatron tune by using bunch-by-bunch transverse beam position. The following items will be presented, (1) least square fitting to the time-domain beam position at specific location. (2) peak finding of the frequency-domain beam position at specific location. (3) phase space analysis of the beam position at specific location.(4) frequency-domain analysis of the beam position in the normalized coordinate at many locations in the ring orbit. For the application to the real accelerator, data of the J-PARC (Japan Proton Accelerator Research Complex) will be shown.

MOPPR038	Bunch by Bunch Beam Diagnostics in SSRF	damping, wakefield, diagnostics, injection	861
	Y.B. Leng, J. Chen, Z.C. Chen, Y.B. Yan, N. Zhang SSRF, Shanghai, People's Republic of China B.P. Wang SINAP, Shanghai, People's Republic of China
	A set of broadband beam instruments including filling pattern monitor, scope based BPM processor and streak camera has been implemented in the storage ring of SSRF. Several parameters such as charge, lifetime, transverse position, betatron tune and beam length, can be measured for individual bunch by these devices. The operation experience and measurement results will be introduced. The preliminary effort to retrieve wake field information from these measurements will be presented as well.

TUYB03	FFAG Experience and Future Prospects	acceleration, proton, focusing, lattice	1054
	Y. Mori Kyoto University, Research Reactor Institute, Osaka, Japan
	This talk should outline the various FFAG accelerators that have been constructed, and discuss the operational experience with different machines. Common issues should be identified, and contrasting experiences highlighted. A frank assessment of the capability of FFAGs to meet the requirements for applications such as ion therapy, accelerator-driven subcritical reactors, and muon colliders should be followed by a description of the main objectives and challenges for future R&D.
	Slides TUYB03 [14.162 MB]

TUEPPB006	Direct Numerical Modeling of E-Cloud Driven Instability of Three Consecutive Batches in the CERN SPS	electron, simulation, emittance, feedback	1125
	J.-L. Vay, M.A. Furman, M. Venturini LBNL, Berkeley, California, USA
	Funding: Supported by the US-DOE under Contract DE-AC02-05CH11231, the SciDAC program ComPASS and the US-LHC Accelerator Research Program (LARP). Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. The simulation package WARP-POSINST was recently upgraded for handling multiple bunches and modeling concurrently the electron cloud buildup and its effect on the beam, allowing for direct self-consistent simulation of bunch trains generating, and interacting with, electron clouds. We have used the WARP-POSINST package on massively parallel supercomputers to study the buildup and interaction of electron clouds with a proton bunch train in the CERN SPS accelerator. Results suggest that a positive feedback mechanism exists between the electron buildup and the e-cloud driven transverse instability, leading to a net increase in predicted electron density. Used resources of NERSC.

TUPPC003	Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors	coupling, quadrupole, emittance, sextupole	1152
	A. Chancé, J. Payet CEA/DSM/IRFU, France B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC004	Study of a Lattice with a Lower Emittance at SOLEIL	emittance, dipole, lattice, optics	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.

TUPPC015	Local Modification of Lattice of a Long Straight Section for Installing Small Gap In-vacuum Undulators at SPring-8	lattice, dynamic-aperture, sextupole, electron	1188
	K. Soutome, T. Fujita, K. Fukami, K.K. Kaneki, C. Mitsuda, H. Ohkuma, M. Oishi, Y. Okayasu, S. Sasaki, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, Y. Taniuchi, C. Zhang JASRI/SPring-8, Hyogo-ken, Japan M. Hasegawa, K. Kajimoto, T. Nakanishi SES, Hyogo-pref., Japan
	In the SPring-8 storage ring there are four magnet-free long straight sections (LSS) of about 30m. Recently we locally modified one of these sections by installing two quadrupole-triplets and divided it into three sub-sections. The vertical beta at the middle of each sub-section was lowered to 2.5m so that small gap in-vacuum undulators with a short period (min. gap: 5.2mm, period: 19mm) can be installed to build a high performance beamline for inelastic X-ray scattering. After modifying the lattice, however, the symmetry of the ring is lowered and, in general, it becomes difficult to keep sufficient dynamic aperture (DA) and momentum acceptance (MA). We solved this problem by combining the betatron phase matching, local chromaticity correction in LSS and cancellation of non-linear kicks due to sextupoles used for this correction. We could then recover DA and MA to almost the same level for the original one. The beam commissioning of the new lattice has successfully been finished, and from September 2011 it is used in user-operation. We will report our method of realizing a storage ring lattice having a very low symmetry and review the operation performance of the modified lattice.

TUPPC016	Progress of Emittance Coupling Correction at the SPring-8 Storage Ring	coupling, resonance, storage-ring, survey	1191
	M. Takao, M. Masaki, Y. Shimosaki, K. Soutome, S. Takano, C. Zhang JASRI/SPring-8, Hyogo-ken, Japan
	The vertical beam spread, or the emittance coupling, is one of the most important parameters for the high brilliance light source storage ring. By the precise alignment of the magnets and the proper COD correction, at the commissioning phase of the SPring-8 storage ring we succeeded in achieving the very small coupling ~0.2 % without correction. However, the coupling had grown large with the years, so recently we have corrected it and recovered the initial performance. The scheme of the coupling correction at the SPring-8 storage ring is the global one, which is based on the perturbation theory with single resonance approximation. In the beginning of the correction the coupling was corrected by means of minimizing the vertical beam size. Then the performance of the coupling correction has been further improved by changing the scheme to minimizing the betatron coupling mode in the vertical oscillation of the horizontally kicked beam. This result implies that the higher order coupling contributes to the emittance coupling, which can be corrected by the higher skew multi-pole magnet. The present status of the coupling correction at the SPring-8 storage ring will be reported.

TUPPC063	The AGS Synchrotron with Four Helical Magnets	injection, resonance, optics, quadrupole	1320
	N. Tsoupas, H. Huang, W.W. MacKay, T. Roser, D. Trbojevic BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US Department of Energy. The idea of using two partial helical magnets was applied successfully to the AGS synchrotron, to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. This modification provides many advantages over the present setup of the AGS that uses two partial helical magnets. First, the symmetric placement of the four helical magnets allows for a better control of the AGS optics with reduced values of the beta functions especially near beam injection, second, the vertical spin direction during beam injection and extraction is closer to vertical, and third, it provides a larger “spin tune gap” for the placement of both the vertical and horizontal tunes of the AGS during acceleration, second. Although the same spin gap can be obtained with two partial helices of equal strength, the required strength of the two helices makes it impractical. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and comparison of these results with the present setup of the AGS that uses two partial helical magnets. T. Roser et al., Proc. EPAC04, p. 1577 (2004). H. Huang et al., PRL 99, 154801(2007). * N. Tsoupas et. al., these proceedings.

TUPPC069	Third-Order Apochromatic Drift-Quadrupole Beamline	quadrupole, beam-transport, resonance, focusing	1329
	N. Golubeva, V. Balandin, R. Brinkmann, W. Decking DESY, Hamburg, Germany
	We have shown that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions. In this paper we continue the development of the theory of apochromatic focusing and present the design of a straight drift-quadrupole system which can transport apochromatic beam ellipses without influence not only of the second but also of the third order chromatic and geometric aberrations of the beamline transfer map. V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Apochromatic Beam Transport in Drift-Quadrupole Systems. Proceedings of IPAC'10, Kyoto, Japan.

TUPPC082	Non-linear Beam Dynamics Tests at the CERN PS in the Framework of the Multi-turn Extraction	pick-up, synchrotron, extraction, coupling	1365
	M. Giovannozzi, G. Arduini, J.M. Belleman, S.S. Gilardoni, C. Hernalsteens, A. Lachaize, G. Métral, Y. Papaphilippou CERN, Geneva, Switzerland
	In the framework of the CERN PS Multi-Turn Extraction several campaigns of measurements probing the non-linear beam dynamics have been carried out. These measurements range from the measurement of non-linear chromaticity to phase space portraits, de-coherence and re-coherence measurements, secondary island tune etc. In this paper these measurements will be reviewed and the results presented and discussed in details.

TUPPC090	Beam Physics of Integrable Optics Test Accelerator at Fermilab	simulation, resonance, lattice, optics	1371
	A. Valishev, S. Nagaitsev Fermilab, Batavia, USA V.V. Danilov ORNL, Oak Ridge, Tennessee, USA D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Fermilab's Integrable Optics Test Accelerator is an electron storage ring designed for testing advanced accelerator physics concepts, including implementation of nonlinear integrable beam optics and experiments on optical stochastic cooling. The machine is currently under construction at the Advanced Superconducting Test Accelerator facility. In this report we present the goals and the current status of the project, and describe the details of machine design. In particular, we concentrate on numerical simulations setting the requirements on the design and supporting the choice of machine parameters.

TUPPC100	On Quantum Integrable Systems	lattice, plasma, synchrotron, focusing	1392
	V.V. Danilov ORNL, Oak Ridge, Tennessee, USA S. Nagaitsev Fermilab, Batavia, USA
	Funding: This research is sponsored by Oak Ridge National Lab, under Contract No. DE-AC05-00OR22725, and Fermi National Lab, under Contract No. DE-AC02-07CH11359. Many quantum integrable systems are obtained using an accelerator physics technique known as Ermakov (or normalized variables) transformation. This technique was used to create classical nonlinear integrable lattices for accelerators and nonlinear integrable plasma traps. Now, all classical results are carried over to a nonrelativistic quantum case.

TUPPD015	Optimization of Muon Capturing in g-2 Ring	kicker, vacuum, impedance, closed-orbit	1440
	A.A. Mikhailichenko CLASSE, Ithaca, New York, USA D.L. Rubin Cornell University, Ithaca, New York, USA
	We describe optimization procedure for muons capturing in g-2 ring under reconstruction at FERMILAB. This procedure includes both the beam dynamics consideration and HV inflector geometry and technique. Some engineering aspects of HV inflector and pulser are presented in detail.

TUPPD021	Orbit Correction in the EMMA Non-scaling FFAG – Simulation and Experimental Results	closed-orbit, quadrupole, pick-up, target	1455
	D.J. Kelliher, S. Machida, S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom J.S. Berg BNL, Upton, Long Island, New York, USA J.K. Jones, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom E. Keil Honorary CERN Staff Member, Berlin, Germany I.W. Kirkman The University of Liverpool, Liverpool, United Kingdom
	The non-scaling FFAG EMMA (Electron Model for Many Applications) is currently in operation at Daresbury Laboratory, UK. Since the lattice is made up solely of linear elements, the betatron tune varies strongly over the momentum range according to the natural chromaticity. Orbit correction is complicated by the resulting variation in response to corrector magnet settings. We consider a method to optimise correction over a range of fixed momenta and discuss experimental results. Measurements of the closed orbit and response matrix are included.

TUPPP034	BPM Gains and Beta Function Measurement Using MIA and FPGA BPMs at the APS	lattice, optics, quadrupole, feedback	1686
	C.-X. Wang, G. Decker, H. Shang, C. Yao ANL, Argonne, USA D. Ji IHEP, Beijing, People's Republic of China
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The broadband BPM system at the Advanced Photon Source (APS) is being upgraded with FPGA-based beam history modules, which fix problems in the old history modules and increase functionality. Using these new turn-by-turn BPMs and the newly developed real-time feedback system, measurement of BPM gains, beta function and other optics functions are being developed based on model-independent analysis of turn-by-turn data and model fitting, aiming at quasi-real-time and high-accuracy optics measurement. We will discuss our effort, especially experience with strong nonlinearity and wakefields typical of 3rd-generation light sources.

TUPPR030	Thermo-mechanical Analysis of the CLIC Post-Linac Energy Collimators	linac, injection, simulation, collimation	1882
	J. Resta-López IFIC, Valencia, Spain J.L. Fernández-Hernando STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A. Latina CERN, Geneva, Switzerland
	Funding: FPA2010-21456-C02-01 The post-linac energy collimation system of the Compact Linear Collider (CLIC) has been designed for passive protection of the Beam Delivery System (BDS) against mis-steered beams due to failure modes in the main linac. In this paper, a thermo-mechanical analysis of the CLIC energy collimators is presented. This study is based on simulations using the codes FLUKA and ANSYS when an entire bunch train hit the collimators. Different failure mode scenarios in the main linac are considered. Moreover, we discuss the results for different collimator materials. The aim is to improve the collimator design in order to make a reliable and robust design so that it survives without damage from the impact of a full bunch train in case of likely events generating energy errors.

TUPPR077	Simulation Studies for the LHC Long-Range Beam-Beam Compensators	optics, simulation, resonance, collider	2002
	T.L. Rijoff, R.J. Steinhagen, F. Zimmermann CERN, Geneva, Switzerland
	The LHC performance and the minimum crossing angle are limited by long-range beam-beam collisions. Wire compensators can mitigate part of the long-range effects and may allow for smaller crossing angles, smaller β^*, or higher beam intensity. A prototype long-range wire compensator should be installed in the LHC by 2014/15. We report simulation studies examining and comparing the efficiency of the wire compensation, in terms of tune footprint or dynamic aperture, at various candidate locations, with different wire shapes, and for varying transverse distance from the beam.

WEOAB01	New Results from the EMMA Experiment	acceleration, injection, resonance, electron	2134
	B.D. Muratori, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom C.S. Edmonds, K.M. Hock, M.G. Ibison, I.W. Kirkman The University of Liverpool, Liverpool, United Kingdom J.M. Garland, H.L. Owen UMAN, Manchester, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	EMMA (Electron Model for Many Applications) is a prototype non-scaling electron FFAG hosted at Daresbury Laboratory. After demonstration of acceleration in the serpentine channel in April 2011, the beam study with EMMA continues to explore the large transverse and longitudinal acceptance and effects of integer tune crossing with slower rate on the betatron amplitude. Together with a comparison of detailed models based on measured field maps and the experimental mapping of the machine by relating the initial and final phase space coordinates. These recent results together with more practical improvements such as injection orbit matching with real-time monitoring of the coordinates in the transverse phase space will be reported in this paper.
	Slides WEOAB01 [2.120 MB]

WEPPP005	Progress on Muon Parametric-resonance Ionization Cooling Channel Development	resonance, emittance, simulation, quadrupole	2729
	V.S. Morozov, Y.S. Derbenev JLAB, Newport News, Virginia, USA A. Afanasev GWU, Washington, USA K.B. Beard, R.P. Johnson Muons, Inc, Batavia, USA B. Erdelyi, J.A. Maloney Northern Illinois University, DeKalb, Illinois, USA
	Funding: Supported in part by DOE SBIR grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Parametric-resonance Ionization Cooling (PIC) is intended as the final 6D cooling stage of a high-luminosity muon collider. To implement PIC, a continuous-field twin-helix magnetic channel was developed. A 6D cooling with stochastic effects off is demonstrated in a GEANT4/G4beamline model of a system where wedge-shaped Be absorbers are placed at the appropriate dispersion points in the twin-helix channel and are followed by short rf cavities. To proceed to cooling simulations with stochastics on, compensation of the beam aberrations from one absorber to another is required. Initial results on aberration compensation using a set of various-order continuous multipole fields are presented. As another avenue to mitigate the aberration effect, we optimize the cooling channel’s period length. We observe a parasitic parametric resonance naturally occurring in the channel’s horizontal plane due to the periodic beam energy modulation caused by the absorbers and rf. We discuss options for compensating this resonance and/or properly combining it with the induced half-integer parametric resonance needed for PIC. 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.

WEPPR006	Serpentine Acceleration in Scaling FFAG	acceleration, proton, closed-orbit, injection	2946
	E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan K. Okabe, I. Sakai University of Fukui, Faculty of Engineering, Fukui, Japan
	A serpentine acceleration in scaling FFAG accelerator is examined. In this scheme, high-energy and high-current beam can be obtained in non-relativistic energy region. Longitudinal hamiltonian is derived analytically. Experiment to demonstrate a serpentine acceleration in scaling FFAG is done.

WEPPR038	Independent Component Analysis (ICA) Applied to Long Bunch Beams in the Los Alamos Proton Storage Ring	linac, injection, extraction, coupling	3018
	J.S. Kolski, R.J. Macek, R.C. McCrady, X. Pang LANL, Los Alamos, New Mexico, USA
	Independent component analysis (ICA) is a powerful blind source separation (BSS) method. Compared to the typical BSS method, principal component analysis (PCA), which is the BSS foundation of the well known model independent analysis (MIA), ICA is more robust to noise, coupling, and nonlinearity. ICA of turn-by-turn beam position data has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch and discuss the source signals identified as betatron motion and longitudinal beam structure.

WEPPR051	Issues for a Multi-bunch Operation with SPARC C-band Cavities	wakefield, HOM, linac, dipole	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.

WEPPR058	The Vertical Impedance Distribution Measurement Using Response Matrix Method at BEPCII BPR	impedance, kicker, feedback, injection	3057
	Y. Wei, D. Ji IHEP, Beijing, People's Republic of China
	Funding: Work supported by the Chinese National Foundation of Natural Sciences, contract 111100512108. In the last run of BEPCII, the single bunch current is limited to about 8mA by the beam-beam effect. To obtain the design luminosity, larger number of bunches are necessary. But higher total current may be limited by the collective effects. A good understanding of the transverse impedance distribution around the BEPCII storage ring is required. Response matrix method has been applied successfully in BEPCII to fit the quadrupole errors and restore the optics. We can also calculate the variation of betatron phase advance around the ring with different single bunch current using the response matrix method and the transverse impedance distribution is thus deduced. In this paper, the first measurement of transverse impedance in BEPCII is presented.

WEPPR087	Dependence of Beam Instabilities Caused by Electron Clouds at CesrTA Due to Variations in Chromaticity, Bunch Current and Train Length	electron, feedback, emittance, positron	3135
	M.G. Billing, G. Dugan, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, J.P. Sikora, K.G. Sonnad, H.A. Williams CLASSE, Ithaca, New York, USA J.Y. Chu CMU, Pittsburgh, Pennsylvania, USA J.W. Flanagan KEK, Ibaraki, Japan R. Holtzapple, M. Randazzo CalPoly, San Luis Obispo, California, USA
	Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867 and the Lepton Collider R&D Coop Agreement: NSF Award PHY-1002467. Electron cloud-induced beam dynamics is being studied at CESRTA under various conditions. These measurements detect the the coherent self-excited spectrum for each bunch within a train and bunch-by-bunch beam size. In the position spectrum coherent betatron dipole and head-tail motion is detectable for each individual bunch within the train with a sensitivity for the motion of 1.1 (2) microns-rms in the vertical (horizontal) direction for a 1 mA bunch current. These techniques are utilized to study the electron cloud-related interactions, which cause the growth of coherent motion and beam size along the train. We report on the observations and results from studies of the instability growth vs. changes in chromaticity, the current per bunch and the length of the train.

THPPD025	Expected and Measured Behaviour of the Tune in the LHC Operation at 3.5 TeV	injection, quadrupole, dipole, feedback	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.

THPPP019	Tune Determination of Strongly Coupled Betatron Oscillations in a Fast Ramping Synchrotron	coupling, booster, damping, quadrupole	3770
	Y. Alexahin, E. Gianfelice-Wendt, W.L. Marsh, A.K. Triplett Fermilab, Batavia, USA
	Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Tune identification - i.e. attribution of the spectral peak to a particular normal mode of oscillations - can present a significant difficulty in the presence of strong transverse coupling when the normal mode with a lower damping rate dominates spectra of Turn-by-Turn oscillations in both planes. The introduced earlier phased sum algorithm* helped to recover the weaker normal mode signal from the noise, but by itself proved to be insufficient for automatic peak identification in the case of close phase advance distribution in both planes. To resolve this difficulty we modified the algorithm by taking and analyzing Turn-by-Turn data for two different ramps with the beam oscillation excited in each plane in turn. Comparison of the relative amplitudes of Fourier components allows for automatic correct tune identiﬁcation. The proposed algorithm was implemented in the Fermilab Booster B38 console application and successfully used in tune, coupling and chromaticity measurements. * Y. Alexahin, E. Gianfelice-Wendt, W. Marsh, Proc. IPAC10, Kyoto, May 2010, p. 1179.

THPPP097	Diagnostic Pulse for Single-particle-like Beam Position Measurements During Accumulation/Production Mode in the Los Alamos Proton Storage Ring	diagnostics, injection, linac, LLRF	3960
	J.S. Kolski, S.A. Baily, E. Björklund, G.O. Bolme, M.J. Hall, S. Kwon, M.P. Martinez, M.S. Prokop, F.E. Shelley, P.A. Torrez LANL, Los Alamos, New Mexico, USA
	Beam position monitors (BPMs) are the primary diagnostic in the Los Alamos Proton Storage Ring (PSR). Injecting one turn, the transverse motion is approximated as a single particle with initial betatron position and angle (x0 and x0'). With single-turn injection, we fit the betatron tune, closed orbit (CO), and injection offset (x0 and x0' at the injection point) to the turn-by-turn beam position. In production mode, we accumulate multiple turns, the transverse phase space fills after 5 injections (horizontal and vertical fractional betatron tunes ~0.2) resulting in no coherent betatron motion, and only the CO may be measured. The injection offset, which determines the accumulated beam size and is very sensitive to steering upstream of the ring, is not measurable in production mode. We describe our approach and ongoing efforts to measure the injection offset during production mode by injecting a ‘‘diagnostic'' pulse ~50 us after the accumulated beam is extracted. We also study the effects of increasing the linac RF gate length to accommodate the diagnostic pulse on the production beam position, transverse size, and loss.

THPPR013	Beam Transport in Alternative Lattices at the University of Maryland Electron Ring (UMER)	lattice, quadrupole, injection, focusing	3993
	S. Bernal, B.L. Beaudoin, M. Cornacchia, R.A. Kishek, D.F. Sutter UMD, College Park, Maryland, USA
	Funding: This work is funded by the US Dept. of Energy Offices of High Energy Physics and High Energy Density Physics, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office. We discuss the motivation, general procedure and results of first experiments of beam transport with two alternative focusing schemes at UMER, a low-energy (10 keV), high-current (1-100 mA) electron storage ring. The new ring optics simplifies injection and RMS envelope matching, and gives us a larger number of beam position monitors (BPMs) per (un-depressed) betatron wavelength, all of which are desirable conditions for better orbit control. Furthermore, one of the new optics schemes is more symmetrical than the standard one, facilitating e.g. the implementation of quadrupole scans for betatron resonance studies. The alternative lattices also allow us to expand significantly on the tune parameter space available for the study of space-charge dominated beam transport.

THPPR038	Failure Studies at the Compact Linear Collider: Main Linac and Beam Delivery System	linac, quadrupole, wakefield, extraction	4056
	C.O. Maidana, M. Jonker, A. Latina CERN, Geneva, Switzerland
	The proposed Compact Linear Collider (CLIC) is based on a two-beam acceleration scheme. The energy of two high-intensity, low-energy drive beams is extracted and transferred to two low-intensity, high-energy main beams. The machine protection and electrical integrity group has the mission to protect the various machine components from damage caused by ill controlled beams. Various failure scenarios were studied and the potential damage these failures could cause to the machine structures were estimated. In this paper, first results of the beam response to correctors and/or quadrupole kick failures in the main linac and in the beam delivery system (BDS) sections are presented as well as possible collimator damage scenarios. The use of the code PLACET for machine protection analysis is described as well.

Paper

Title

Other Keywords

Page

MOYCP01

Design and Simulation of IOTA - a Novel Concept of Integrable Optics Test Accelerator

electron, focusing, optics, simulation

16

S. Nagaitsev, A. Valishev
Fermilab, Batavia, USA
V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

The use of nonlinear lattices with large betatron tune spreads can increase instability and space charge thresholds due to improved Landau damping. Unfortunately, the majority of nonlinear accelerator lattices turn out to be nonintegrable, producing chaotic motion and a complex network of stable and unstable resonances. Recent advances in finding the integrable nonlinear accelerator lattices have led to a proposal to construct at Fermilab a test accelerator with strong nonlinear focusing which avoids resonances and chaotic particle motion. This presentation will outline the main challenges, theoretical design solutions and construction status of the Integrable Optics Test Accelerator underway at Fermilab.

Slides MOYCP01 [2.816 MB]

MOEPPB007

Studies of eRHIC Coherent Instabilities

proton, simulation, impedance, space-charge

91

G. Wang, M. Blaskiewicz
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the presence of an effective coherent electron cooling, the rms ion bunch length in eRHIC will be kept at 8.4cm, which is about a factor of 3 shorter than the current RHIC rms bunch length. Together with a factor of 2 increase in bunch intensity, coherent instabilities could be a potential limitation for achieving desired machine performance. In this study, we use the tracking code TRANFT to find thresholds and growth rates for various single bunch and coupled bunch instabilities with linear chromaticity and amplitude dependent tune shift taken into account. Based on the simulation results, requirements of machine parameters such as rf voltage, linear chromaticity, and octupole strength are specified to avoid these instabilities.

MOEPPB015

Excitation of Intra-bunch Vertical Motion in the SPS - Implications for Feedback Control of Ecloud and TMCI Instabilities

resonance, pick-up, feedback, synchrotron

112

J.D. Fox, J.M. Cesaratto, M.T.F. Pivi, C.H. Rivetta, O. Turgut, S. Uemura
SLAC, Menlo Park, California, USA
W. Höfle, U. Wehrle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
Electron cloud and transverse mode coupled-bunch instabilities (TMCI) limit the bunch intensity in the CERN SPS. Intra-bunch fast feedback systems are a possible method to control these effects. This paper presents experimental measurements of single-bunch motion in the SPS driven by a GHz bandwidth vertical excitation system*. The primary goal is to quantify the change in internal bunch dynamics as instability thresholds are approached, and quantify the frequencies of internal modes as Ecloud effects become significant. The beam response is sampled at 20 GS/sec. in response to arbitrary excitation patterns, with data in 2011 taken at 3 bunch intensities. We show the excitation of barycentric, head-tail and higher vertical modes. The beam motion is analyzed in the time domain, via animated presentations of the sampled vertical signals, and in the frequency domain, via spectrograms showing the modal frequencies vs. time. The demonstration of the excitation of selected internal modes is a significant step in development of the feedback control techniques.
* "A 4 GS/Sec. Synchronized Vertical Excitation System for SPS Studies - Steps Towards Wideband Feedback," these proceedings.

MOPPC003

Very Fast LHC Crab Cavity Failures and their Mitigation

luminosity, simulation, cavity, optics

121

T. Baer, R. Calaga, R. De Maria, S.D. Fartoukh, E. Jensen, R. Tomás, J. Tückmantel, J. Wenninger, B. Yee-Rendon, F. Zimmermann
CERN, Geneva, Switzerland
T. Baer
University of Hamburg, Hamburg, Germany

For the high-luminosity LHC upgrade program (HL-LHC), the installation of crab cavities (CCs) is needed to compensate the geometric luminosity loss due to the crossing angle and for luminosity leveling [*]. The baseline is a local scheme with CCs around the ATLAS and CMS experiments. In a failure case (e.g. a control failure or arcing in the coupler), the voltage and/or phase of a CC can change significantly with a very fast time constant of the order of 1 to 10 LHC turns. This can lead to large, global betatron oscillations of the beam. The impact of CC failures on the beam dynamics is discussed and the results from dedicated simulations are presented. Mitigation strategies to limit the impact of CC failures to an acceptable level are proposed.
* F. Zimmermann and O. Brüning, “Parameter Space for the LHC High-Luminosity Upgrade”, IPAC'12, MOPPC005, May 2012.

MOPPC021

Explore the Possibility of Accelerating Polarized He-3 Beam in RHIC

resonance, proton, closed-orbit, neutron

172

M. Bai, E.D. Courant, W. Fischer, V. Ptitsyn, 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.
As the world’s first high energy polarized proton collider, RHIC has made significant progress in measuring the proton spin structure in the past decade. In order to have better understanding of the contribution of up and down quarks to the proton spin structure, collisions of high energy polarized neutron beams are required. In this paper, we present studies of accelerating polarized Helium-3 in RHIC with the current dual snake configuration. The possibilities of adding two more pairs of snakes for accelerating polarized He-3 were explored. Results of a six snake configuration in RHIC are also reported in the paper.

MOPPC027

Synchro-Betatron Effects in the Presence of Large Piwinski Angle and Crab Cavities at the HL-LHC

luminosity, simulation, coupling, damping

190

S.M. White
BNL, Upton, Long Island, New York, USA
R. Calaga
CERN, Geneva, Switzerland
R. Miyamoto
ESS, Lund, Sweden

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
The reduction of beta-star at the collision points for the high luminosity LHC (HL-LHC) requires an increment in the crossing angle to maintain the normalized beam separation to suppress the effects of long-range beam-beam interactions. However, increase in crossing angle may give rise to synchro-betatron resonances which may negatively affect the beam emittance and lifetime. 6D weak-strong and strong-strong simulations are performed to study the effect of synchro-betatron resonances in the context of the HL-LHC layout and its suppression via crab crossing.

MOPPC032

Injection and Broadband Matching for the PRISM Muon FFAG

injection, solenoid, target, dipole

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.

MOPPC076

New Features of the Parallel TRACY for Nonlinear Beam Dynamics

lattice, dynamic-aperture, sextupole, closed-orbit

310

M.-S. Chiu, H.-P. Chang
NSRRC, Hsinchu, Taiwan

The TRACY code is used to analyze and simulate the nonlinear beam dynamics of the designed lattice. To speed up the lattice design flow, we parallelized the TRACY by MPI and developed a GUI by GTK+ to integrate the functions of TRACY and added a function of nonlinear optimization adapted from OPA, which is used to optimize the nonlinear driving terms by powell algorithm. The GUI is used for parameter input and data visualization. The procedures of nonlinear optimization and beam dynamics analysis are integrated and streamlined. Users do not need to write and compile the code any more. The results will be demonstrated in this report.

MOPPC077

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

booster, lattice, multipole, synchrotron

313

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

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

MOPPD011

Analysis of Frequency Spectrum of Bunched Beam Related to Transverse Laser Cooling*

synchrotron, laser, coupling, ion

391

K. Jimbo
Kyoto University, Institute for Advanced Energy, Kyoto, Japan
Z.Q. He
TUB, Beijing, People's Republic of China
M. Nakao, A. Noda, H. Souda, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan

Using synchro-betatron coupling, transverse laser cooling is pursued at an ion storage/cooler ring, S-LSR, Kyoto University. A bunched 40 keV 24Mg+ beam was cooled by a co-propagating laser of 280 nm wavelength. Synchrotron oscillation in the longitudinal direction and betatron oscillation in the horizontal direction were intentionally coupled by an RF drift tube located at the finite dispersive section (D =1.1 m) where longitudinal cooling force was transmitted to the horizontal direction.* Analyzing bunched Schottky signals, which represents longitudinal physical quantities of the beam, we try to obtain an evidence of synchro-betatron coupling and accordingly laser cooling of the beam in the transverse direction.
* H. Okamoto, Phys. Rev. E 50, 4982 (1994)

MOPPD012

Challenge for More Efficient Transverse Laser Cooling for Beam Crystallization

laser, synchrotron, ion, simulation

394

A. Noda, M. Nakao, H. Souda, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
M. Grieser
MPI-K, Heidelberg, Germany
Z.Q. He
TUB, Beijing, People's Republic of China
K. Ito, H. Okamoto, K. Osaki
HU/AdSM, Higashi-Hiroshima, Japan
K. Jimbo
Kyoto University, Institute for Advanced Energy, Kyoto, Japan
Y. Yuri
JAEA/TARRI, Gunma-ken, Japan

Funding: Work supported by Advanced Compact Accelerator Development project by MEXT. Also supported by GCOE project at Kyoto University, The next generation of Physics-Spun from Universality and Emergency.
At S-LSR in ICR, Kyoto University, Mg ion beam has been successfully laser cooled both in longitudinal* and transverse** directions. The cooling rate, however, is not strong enough to realize the crystalline beam due to the heating because of intra-beam scattering (IBS) effect. So as to suppress this IBS, reduction of the beam intensity is inevitable, which however, had resulted in poor S/N ratio for observation of the transverse beam size. In the present paper, we would like to describe a new beam scraping scheme, which selects out the beams in the distribution tail of the transverse phase space keeping the beam density in the core part by simultaneous application of multi-dimensional laser cooling and beam scraping. The strategy to reduce the beam intensity and hence beam heating due to IBS by a controlled scraping of the outskirt beam keeping the beam density at core part almost the same, has been searched by combination of the beam experiments and computer simulations.
* M. Tanabe et al., Applied Physics Express 1, 028001 (2008).
** M. Nakao et al., submitted to PRST-AB.

MOPPD013

Observation of 2-Component Bunched Beam Signal with Laser Cooling

laser, ion, coupling, injection

397

H. Souda, M. Nakao, A. Noda, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
M. Grieser
MPI-K, Heidelberg, Germany
Z.Q. He
TUB, Beijing, People's Republic of China
K. Ito, H. Okamoto
HU/AdSM, Higashi-Hiroshima, Japan
K. Jimbo
Kyoto University, Institute for Advanced Energy, Kyoto, Japan
Y. Yuri
JAEA/TARRI, Gunma-ken, Japan

Funding: Work supported by Advanced Compact Accelerator Development Project of MEXT, Global COE program "The Next Generation of Physics, Spun from Universality and Emergence" and Grant-in-Aid for JSPS Fellows.
Longitudinal beam temperature during a laser cooling was measured through bunch length measurement at S-LSR. 40keV 24Mg+ beams were bunched by an RF voltage with a harmonic number of 5 and were cooled by a co-propagating laser with a wavelength of 280nm*. Bunch length was measured by time-domain signal from a pair of parallel-plate electrostatic pickups with a length of 140mm. Injected non-cooled beams gave a bunch length of 2.5m (2-σ) and cooled beam has a 2-component of broad and sharp distribution. Broad distribution had a longitudinal length of 2.2m, which is close to that of initial beam. The length of the sharp distribution shrunk to 0.25m and is considered as a cooled part. Capture efficiency of cooling, which represents the ratio of the particle numbers of cooled part and the total particle number, varies by the change of the detuning of the laser (fixed frequency or scanning). With scanning range of 2GHz, capture efficiency was improved from 66% to 92%, whereas the bunch became longer by 10% with scanning. Approach to improve the number of cooled particle and cut uncooled part** will be applied to attain a strong signal with a low-current beam with a low temperature.
* J. S. Hangst et al., Phys. Rev. Lett. 74, 4432 (1995).
** A. Noda et al., these proceedings.

MOPPD067

Novel Slow Extraction Scheme for Proton Accelerators Using Pulsed Dipole Correctors and Crystals

extraction, septum, proton, scattering

517

V.D. Shiltsev
Fermilab, Batavia, USA

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359
Slow extraction of protons beams from circular accelerators is currently widely used for a variety of beam-based experiments. The method has some deficiencies including limited efficiency of extraction, radiation induced due to scattering on the electrostatic septa and limited beam pipe aperture, beam dynamics effects of space charge forces and magnet power supplies ripple. Here we present a novel slow extraction scheme employing a number of non-standard accelerator elements, such as Silicone crystal strips and pulsed strip-line dipole correctors, and illustrate practicality of these examples at the 8 GeV proton Recycler Ring at Fermilab.

MOPPD077

Studies for an Alternative LHC Non-Linear Collimation System

collimation, proton, sextupole, impedance

544

L. Lari, R.W. Assmann, V. Boccone, F. Cerutti, A. Mereghetti, R. Versaci, V. Vlachoudis
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari, J. Resta-López
IFIC, Valencia, Spain

Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program.
A LHC nonlinear Betatron cleaning collimation system would allow larger gap for the mechanical jaws, reducing as a consequence the collimator-induced impedance, which may limit the LHC beam intensity. In this paper, the performance of the proposed system is analyzed in terms of beam losses distribution around the LHC ring and cleaning efficiency in stable physics condition at 7TeV for Beam1. Moreover, the energy deposition distribution on the machine elements is compared to the present LHC Betatron cleaning collimation system in the Point 7 Insertion Region (IR).

MOPPD078

Accelerator Physics Study on the Effects from an Asynchronous Beam Dump in the LHC Experimental Region Collimators

proton, simulation, kicker, optics

547

L. Lari, R.W. Assmann, V. Boccone, R. Bruce, F. Cerutti, A. Mereghetti, A. Rossi, V. Vlachoudis
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain

Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program.
Asynchronous beam aborts at the LHC are to be expected once per year. Accelerator physics studies of asynchronous dumps have been performed at different beam energies and beta-stars. The loss patterns are analyzed in order to identify the losses in particular on the Phase 1 Tertiary Collimators (TCT), since their Tungsten jaw insert has a low damage threshold with respect to the loss load expected. Settings for the tilt angle of the TCTs are discussed with the aim of reducing the thermal loads on the TCT themselves.

MOPPR030

Various Methods to Measure the Betatron Tune of the Synchrotoron

closed-orbit, pick-up, synchrotron, injection

843

S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

Generally in the synchrotron, the frequency of transverse oscillation of the bunched beam for each single turn (usually called betatron tune or just "tune") is one of fundamental controllable knobs to avoid the instability of the accelerator. In this report, it is not mentioned about the effect to the beam instability but it is focused to various methods to measure the betatron tune by using bunch-by-bunch transverse beam position. The following items will be presented, (1) least square fitting to the time-domain beam position at specific location. (2) peak finding of the frequency-domain beam position at specific location. (3) phase space analysis of the beam position at specific location.(4) frequency-domain analysis of the beam position in the normalized coordinate at many locations in the ring orbit. For the application to the real accelerator, data of the J-PARC (Japan Proton Accelerator Research Complex) will be shown.

MOPPR038

Bunch by Bunch Beam Diagnostics in SSRF

damping, wakefield, diagnostics, injection

861

Y.B. Leng, J. Chen, Z.C. Chen, Y.B. Yan, N. Zhang
SSRF, Shanghai, People's Republic of China
B.P. Wang
SINAP, Shanghai, People's Republic of China

A set of broadband beam instruments including filling pattern monitor, scope based BPM processor and streak camera has been implemented in the storage ring of SSRF. Several parameters such as charge, lifetime, transverse position, betatron tune and beam length, can be measured for individual bunch by these devices. The operation experience and measurement results will be introduced. The preliminary effort to retrieve wake field information from these measurements will be presented as well.

TUYB03

FFAG Experience and Future Prospects

acceleration, proton, focusing, lattice

1054

Y. Mori
Kyoto University, Research Reactor Institute, Osaka, Japan

This talk should outline the various FFAG accelerators that have been constructed, and discuss the operational experience with different machines. Common issues should be identified, and contrasting experiences highlighted. A frank assessment of the capability of FFAGs to meet the requirements for applications such as ion therapy, accelerator-driven subcritical reactors, and muon colliders should be followed by a description of the main objectives and challenges for future R&D.

Slides TUYB03 [14.162 MB]

TUEPPB006

Direct Numerical Modeling of E-Cloud Driven Instability of Three Consecutive Batches in the CERN SPS

electron, simulation, emittance, feedback

1125

J.-L. Vay, M.A. Furman, M. Venturini
LBNL, Berkeley, California, USA

Funding: Supported by the US-DOE under Contract DE-AC02-05CH11231, the SciDAC program ComPASS and the US-LHC Accelerator Research Program (LARP).
Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. The simulation package WARP-POSINST was recently upgraded for handling multiple bunches and modeling concurrently the electron cloud buildup and its effect on the beam, allowing for direct self-consistent simulation of bunch trains generating, and interacting with, electron clouds. We have used the WARP-POSINST package on massively parallel supercomputers to study the buildup and interaction of electron clouds with a proton bunch train in the CERN SPS accelerator. Results suggest that a positive feedback mechanism exists between the electron buildup and the e-cloud driven transverse instability, leading to a net increase in predicted electron density.
Used resources of NERSC.

TUPPC003

Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors

coupling, quadrupole, emittance, sextupole

1152

A. Chancé, J. Payet
CEA/DSM/IRFU, France
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC004

Study of a Lattice with a Lower Emittance at SOLEIL

emittance, dipole, lattice, optics

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.

TUPPC015

Local Modification of Lattice of a Long Straight Section for Installing Small Gap In-vacuum Undulators at SPring-8

lattice, dynamic-aperture, sextupole, electron

1188

K. Soutome, T. Fujita, K. Fukami, K.K. Kaneki, C. Mitsuda, H. Ohkuma, M. Oishi, Y. Okayasu, S. Sasaki, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, Y. Taniuchi, C. Zhang
JASRI/SPring-8, Hyogo-ken, Japan
M. Hasegawa, K. Kajimoto, T. Nakanishi
SES, Hyogo-pref., Japan

In the SPring-8 storage ring there are four magnet-free long straight sections (LSS) of about 30m. Recently we locally modified one of these sections by installing two quadrupole-triplets and divided it into three sub-sections. The vertical beta at the middle of each sub-section was lowered to 2.5m so that small gap in-vacuum undulators with a short period (min. gap: 5.2mm, period: 19mm) can be installed to build a high performance beamline for inelastic X-ray scattering. After modifying the lattice, however, the symmetry of the ring is lowered and, in general, it becomes difficult to keep sufficient dynamic aperture (DA) and momentum acceptance (MA). We solved this problem by combining the betatron phase matching, local chromaticity correction in LSS and cancellation of non-linear kicks due to sextupoles used for this correction. We could then recover DA and MA to almost the same level for the original one. The beam commissioning of the new lattice has successfully been finished, and from September 2011 it is used in user-operation. We will report our method of realizing a storage ring lattice having a very low symmetry and review the operation performance of the modified lattice.

TUPPC016

Progress of Emittance Coupling Correction at the SPring-8 Storage Ring

coupling, resonance, storage-ring, survey

1191

M. Takao, M. Masaki, Y. Shimosaki, K. Soutome, S. Takano, C. Zhang
JASRI/SPring-8, Hyogo-ken, Japan

The vertical beam spread, or the emittance coupling, is one of the most important parameters for the high brilliance light source storage ring. By the precise alignment of the magnets and the proper COD correction, at the commissioning phase of the SPring-8 storage ring we succeeded in achieving the very small coupling ~0.2 % without correction. However, the coupling had grown large with the years, so recently we have corrected it and recovered the initial performance. The scheme of the coupling correction at the SPring-8 storage ring is the global one, which is based on the perturbation theory with single resonance approximation. In the beginning of the correction the coupling was corrected by means of minimizing the vertical beam size. Then the performance of the coupling correction has been further improved by changing the scheme to minimizing the betatron coupling mode in the vertical oscillation of the horizontally kicked beam. This result implies that the higher order coupling contributes to the emittance coupling, which can be corrected by the higher skew multi-pole magnet. The present status of the coupling correction at the SPring-8 storage ring will be reported.

TUPPC063

The AGS Synchrotron with Four Helical Magnets

injection, resonance, optics, quadrupole

1320

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

Funding: *Work supported by the US Department of Energy.
The idea* of using two partial helical magnets was applied successfully to the AGS synchrotron**, to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. This modification provides many advantages over the present setup of the AGS that uses two partial helical magnets. First, the symmetric placement of the four helical magnets allows for a better control of the AGS optics with reduced values of the beta functions especially near beam injection, second, the vertical spin direction during beam injection and extraction is closer to vertical, and third, it provides a larger “spin tune gap” for the placement of both the vertical and horizontal tunes of the AGS during acceleration, second. Although the same spin gap can be obtained with two partial helices of equal strength, the required strength of the two helices makes it impractical. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and comparison of these results with the present setup of the AGS that uses two partial helical magnets***.
* T. Roser et al., Proc. EPAC04, p. 1577 (2004).
** H. Huang et al., PRL 99, 154801(2007).
*** N. Tsoupas et. al., these proceedings.

TUPPC069

Third-Order Apochromatic Drift-Quadrupole Beamline

quadrupole, beam-transport, resonance, focusing

1329

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

We have shown that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions*. In this paper we continue the development of the theory of apochromatic focusing and present the design of a straight drift-quadrupole system which can transport apochromatic beam ellipses without influence not only of the second but also of the third order chromatic and geometric aberrations of the beamline transfer map.
* V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Apochromatic Beam Transport in Drift-Quadrupole Systems. Proceedings of IPAC'10, Kyoto, Japan.

TUPPC082

Non-linear Beam Dynamics Tests at the CERN PS in the Framework of the Multi-turn Extraction

pick-up, synchrotron, extraction, coupling

1365

M. Giovannozzi, G. Arduini, J.M. Belleman, S.S. Gilardoni, C. Hernalsteens, A. Lachaize, G. Métral, Y. Papaphilippou
CERN, Geneva, Switzerland

In the framework of the CERN PS Multi-Turn Extraction several campaigns of measurements probing the non-linear beam dynamics have been carried out. These measurements range from the measurement of non-linear chromaticity to phase space portraits, de-coherence and re-coherence measurements, secondary island tune etc. In this paper these measurements will be reviewed and the results presented and discussed in details.

TUPPC090

Beam Physics of Integrable Optics Test Accelerator at Fermilab

simulation, resonance, lattice, optics

1371

A. Valishev, S. Nagaitsev
Fermilab, Batavia, USA
V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy.
Fermilab's Integrable Optics Test Accelerator is an electron storage ring designed for testing advanced accelerator physics concepts, including implementation of nonlinear integrable beam optics and experiments on optical stochastic cooling. The machine is currently under construction at the Advanced Superconducting Test Accelerator facility. In this report we present the goals and the current status of the project, and describe the details of machine design. In particular, we concentrate on numerical simulations setting the requirements on the design and supporting the choice of machine parameters.

TUPPC100

On Quantum Integrable Systems

lattice, plasma, synchrotron, focusing

1392

V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
S. Nagaitsev
Fermilab, Batavia, USA

Funding: This research is sponsored by Oak Ridge National Lab, under Contract No. DE-AC05-00OR22725, and Fermi National Lab, under Contract No. DE-AC02-07CH11359.
Many quantum integrable systems are obtained using an accelerator physics technique known as Ermakov (or normalized variables) transformation. This technique was used to create classical nonlinear integrable lattices for accelerators and nonlinear integrable plasma traps. Now, all classical results are carried over to a nonrelativistic quantum case.

TUPPD015

Optimization of Muon Capturing in g-2 Ring

kicker, vacuum, impedance, closed-orbit

1440

A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA
D.L. Rubin
Cornell University, Ithaca, New York, USA

We describe optimization procedure for muons capturing in g-2 ring under reconstruction at FERMILAB. This procedure includes both the beam dynamics consideration and HV inflector geometry and technique. Some engineering aspects of HV inflector and pulser are presented in detail.

TUPPD021

Orbit Correction in the EMMA Non-scaling FFAG – Simulation and Experimental Results

closed-orbit, quadrupole, pick-up, target

1455

D.J. Kelliher, S. Machida, S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
J.S. Berg
BNL, Upton, Long Island, New York, USA
J.K. Jones, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
E. Keil
Honorary CERN Staff Member, Berlin, Germany
I.W. Kirkman
The University of Liverpool, Liverpool, United Kingdom

The non-scaling FFAG EMMA (Electron Model for Many Applications) is currently in operation at Daresbury Laboratory, UK. Since the lattice is made up solely of linear elements, the betatron tune varies strongly over the momentum range according to the natural chromaticity. Orbit correction is complicated by the resulting variation in response to corrector magnet settings. We consider a method to optimise correction over a range of fixed momenta and discuss experimental results. Measurements of the closed orbit and response matrix are included.

TUPPP034

BPM Gains and Beta Function Measurement Using MIA and FPGA BPMs at the APS

lattice, optics, quadrupole, feedback

1686

C.-X. Wang, G. Decker, H. Shang, C. Yao
ANL, Argonne, USA
D. Ji
IHEP, Beijing, People's Republic of China

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The broadband BPM system at the Advanced Photon Source (APS) is being upgraded with FPGA-based beam history modules, which fix problems in the old history modules and increase functionality. Using these new turn-by-turn BPMs and the newly developed real-time feedback system, measurement of BPM gains, beta function and other optics functions are being developed based on model-independent analysis of turn-by-turn data and model fitting, aiming at quasi-real-time and high-accuracy optics measurement. We will discuss our effort, especially experience with strong nonlinearity and wakefields typical of 3rd-generation light sources.

TUPPR030

Thermo-mechanical Analysis of the CLIC Post-Linac Energy Collimators

linac, injection, simulation, collimation

1882

J. Resta-López
IFIC, Valencia, Spain
J.L. Fernández-Hernando
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A. Latina
CERN, Geneva, Switzerland

Funding: FPA2010-21456-C02-01
The post-linac energy collimation system of the Compact Linear Collider (CLIC) has been designed for passive protection of the Beam Delivery System (BDS) against mis-steered beams due to failure modes in the main linac. In this paper, a thermo-mechanical analysis of the CLIC energy collimators is presented. This study is based on simulations using the codes FLUKA and ANSYS when an entire bunch train hit the collimators. Different failure mode scenarios in the main linac are considered. Moreover, we discuss the results for different collimator materials. The aim is to improve the collimator design in order to make a reliable and robust design so that it survives without damage from the impact of a full bunch train in case of likely events generating energy errors.

TUPPR077

Simulation Studies for the LHC Long-Range Beam-Beam Compensators

optics, simulation, resonance, collider

2002

T.L. Rijoff, R.J. Steinhagen, F. Zimmermann
CERN, Geneva, Switzerland

The LHC performance and the minimum crossing angle are limited by long-range beam-beam collisions. Wire compensators can mitigate part of the long-range effects and may allow for smaller crossing angles, smaller β^*, or higher beam intensity. A prototype long-range wire compensator should be installed in the LHC by 2014/15. We report simulation studies examining and comparing the efficiency of the wire compensation, in terms of tune footprint or dynamic aperture, at various candidate locations, with different wire shapes, and for varying transverse distance from the beam.

WEOAB01

New Results from the EMMA Experiment

acceleration, injection, resonance, electron

2134

B.D. Muratori, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C.S. Edmonds, K.M. Hock, M.G. Ibison, I.W. Kirkman
The University of Liverpool, Liverpool, United Kingdom
J.M. Garland, H.L. Owen
UMAN, Manchester, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

EMMA (Electron Model for Many Applications) is a prototype non-scaling electron FFAG hosted at Daresbury Laboratory. After demonstration of acceleration in the serpentine channel in April 2011, the beam study with EMMA continues to explore the large transverse and longitudinal acceptance and effects of integer tune crossing with slower rate on the betatron amplitude. Together with a comparison of detailed models based on measured field maps and the experimental mapping of the machine by relating the initial and final phase space coordinates. These recent results together with more practical improvements such as injection orbit matching with real-time monitoring of the coordinates in the transverse phase space will be reported in this paper.

Slides WEOAB01 [2.120 MB]

WEPPP005

Progress on Muon Parametric-resonance Ionization Cooling Channel Development

resonance, emittance, simulation, quadrupole

2729

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA
A. Afanasev
GWU, Washington, USA
K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, USA
B. Erdelyi, J.A. Maloney
Northern Illinois University, DeKalb, Illinois, USA

Funding: Supported in part by DOE SBIR grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Parametric-resonance Ionization Cooling (PIC) is intended as the final 6D cooling stage of a high-luminosity muon collider. To implement PIC, a continuous-field twin-helix magnetic channel was developed. A 6D cooling with stochastic effects off is demonstrated in a GEANT4/G4beamline model of a system where wedge-shaped Be absorbers are placed at the appropriate dispersion points in the twin-helix channel and are followed by short rf cavities. To proceed to cooling simulations with stochastics on, compensation of the beam aberrations from one absorber to another is required. Initial results on aberration compensation using a set of various-order continuous multipole fields are presented. As another avenue to mitigate the aberration effect, we optimize the cooling channel’s period length. We observe a parasitic parametric resonance naturally occurring in the channel’s horizontal plane due to the periodic beam energy modulation caused by the absorbers and rf. We discuss options for compensating this resonance and/or properly combining it with the induced half-integer parametric resonance needed for PIC.
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.

WEPPR006

Serpentine Acceleration in Scaling FFAG

acceleration, proton, closed-orbit, injection

2946

E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan
K. Okabe, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan

A serpentine acceleration in scaling FFAG accelerator is examined. In this scheme, high-energy and high-current beam can be obtained in non-relativistic energy region. Longitudinal hamiltonian is derived analytically. Experiment to demonstrate a serpentine acceleration in scaling FFAG is done.

WEPPR038

Independent Component Analysis (ICA) Applied to Long Bunch Beams in the Los Alamos Proton Storage Ring

linac, injection, extraction, coupling

3018

J.S. Kolski, R.J. Macek, R.C. McCrady, X. Pang
LANL, Los Alamos, New Mexico, USA

Independent component analysis (ICA) is a powerful blind source separation (BSS) method. Compared to the typical BSS method, principal component analysis (PCA), which is the BSS foundation of the well known model independent analysis (MIA), ICA is more robust to noise, coupling, and nonlinearity. ICA of turn-by-turn beam position data has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch and discuss the source signals identified as betatron motion and longitudinal beam structure.

WEPPR051

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

wakefield, HOM, linac, dipole

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.

WEPPR058

The Vertical Impedance Distribution Measurement Using Response Matrix Method at BEPCII BPR

impedance, kicker, feedback, injection

3057

Y. Wei, D. Ji
IHEP, Beijing, People's Republic of China

Funding: Work supported by the Chinese National Foundation of Natural Sciences, contract 111100512108.
In the last run of BEPCII, the single bunch current is limited to about 8mA by the beam-beam effect. To obtain the design luminosity, larger number of bunches are necessary. But higher total current may be limited by the collective effects. A good understanding of the transverse impedance distribution around the BEPCII storage ring is required. Response matrix method has been applied successfully in BEPCII to fit the quadrupole errors and restore the optics. We can also calculate the variation of betatron phase advance around the ring with different single bunch current using the response matrix method and the transverse impedance distribution is thus deduced. In this paper, the first measurement of transverse impedance in BEPCII is presented.

WEPPR087

Dependence of Beam Instabilities Caused by Electron Clouds at CesrTA Due to Variations in Chromaticity, Bunch Current and Train Length

electron, feedback, emittance, positron

3135

M.G. Billing, G. Dugan, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, J.P. Sikora, K.G. Sonnad, H.A. Williams
CLASSE, Ithaca, New York, USA
J.Y. Chu
CMU, Pittsburgh, Pennsylvania, USA
J.W. Flanagan
KEK, Ibaraki, Japan
R. Holtzapple, M. Randazzo
CalPoly, San Luis Obispo, California, USA

Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867 and the Lepton Collider R&D Coop Agreement: NSF Award PHY-1002467.
Electron cloud-induced beam dynamics is being studied at CESRTA under various conditions. These measurements detect the the coherent self-excited spectrum for each bunch within a train and bunch-by-bunch beam size. In the position spectrum coherent betatron dipole and head-tail motion is detectable for each individual bunch within the train with a sensitivity for the motion of 1.1 (2) microns-rms in the vertical (horizontal) direction for a 1 mA bunch current. These techniques are utilized to study the electron cloud-related interactions, which cause the growth of coherent motion and beam size along the train. We report on the observations and results from studies of the instability growth vs. changes in chromaticity, the current per bunch and the length of the train.

THPPD025

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

injection, quadrupole, dipole, feedback

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.

THPPP019

Tune Determination of Strongly Coupled Betatron Oscillations in a Fast Ramping Synchrotron

coupling, booster, damping, quadrupole

3770

Y. Alexahin, E. Gianfelice-Wendt, W.L. Marsh, A.K. Triplett
Fermilab, Batavia, USA

Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Tune identification - i.e. attribution of the spectral peak to a particular normal mode of oscillations - can present a significant difficulty in the presence of strong transverse coupling when the normal mode with a lower damping rate dominates spectra of Turn-by-Turn oscillations in both planes. The introduced earlier phased sum algorithm* helped to recover the weaker normal mode signal from the noise, but by itself proved to be insufficient for automatic peak identification in the case of close phase advance distribution in both planes. To resolve this difficulty we modified the algorithm by taking and analyzing Turn-by-Turn data for two different ramps with the beam oscillation excited in each plane in turn. Comparison of the relative amplitudes of Fourier components allows for automatic correct tune identiﬁcation. The proposed algorithm was implemented in the Fermilab Booster B38 console application and successfully used in tune, coupling and chromaticity measurements.
* Y. Alexahin, E. Gianfelice-Wendt, W. Marsh, Proc. IPAC10, Kyoto, May 2010, p. 1179.

THPPP097

Diagnostic Pulse for Single-particle-like Beam Position Measurements During Accumulation/Production Mode in the Los Alamos Proton Storage Ring

diagnostics, injection, linac, LLRF

3960

J.S. Kolski, S.A. Baily, E. Björklund, G.O. Bolme, M.J. Hall, S. Kwon, M.P. Martinez, M.S. Prokop, F.E. Shelley, P.A. Torrez
LANL, Los Alamos, New Mexico, USA

Beam position monitors (BPMs) are the primary diagnostic in the Los Alamos Proton Storage Ring (PSR). Injecting one turn, the transverse motion is approximated as a single particle with initial betatron position and angle (x0 and x0'). With single-turn injection, we fit the betatron tune, closed orbit (CO), and injection offset (x0 and x0' at the injection point) to the turn-by-turn beam position. In production mode, we accumulate multiple turns, the transverse phase space fills after 5 injections (horizontal and vertical fractional betatron tunes ~0.2) resulting in no coherent betatron motion, and only the CO may be measured. The injection offset, which determines the accumulated beam size and is very sensitive to steering upstream of the ring, is not measurable in production mode. We describe our approach and ongoing efforts to measure the injection offset during production mode by injecting a ‘‘diagnostic'' pulse ~50 us after the accumulated beam is extracted. We also study the effects of increasing the linac RF gate length to accommodate the diagnostic pulse on the production beam position, transverse size, and loss.

THPPR013

Beam Transport in Alternative Lattices at the University of Maryland Electron Ring (UMER)

lattice, quadrupole, injection, focusing

3993

S. Bernal, B.L. Beaudoin, M. Cornacchia, R.A. Kishek, D.F. Sutter
UMD, College Park, Maryland, USA

Funding: This work is funded by the US Dept. of Energy Offices of High Energy Physics and High Energy Density Physics, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office.
We discuss the motivation, general procedure and results of first experiments of beam transport with two alternative focusing schemes at UMER, a low-energy (10 keV), high-current (1-100 mA) electron storage ring. The new ring optics simplifies injection and RMS envelope matching, and gives us a larger number of beam position monitors (BPMs) per (un-depressed) betatron wavelength, all of which are desirable conditions for better orbit control. Furthermore, one of the new optics schemes is more symmetrical than the standard one, facilitating e.g. the implementation of quadrupole scans for betatron resonance studies. The alternative lattices also allow us to expand significantly on the tune parameter space available for the study of space-charge dominated beam transport.

THPPR038

Failure Studies at the Compact Linear Collider: Main Linac and Beam Delivery System

linac, quadrupole, wakefield, extraction

4056

C.O. Maidana, M. Jonker, A. Latina
CERN, Geneva, Switzerland

The proposed Compact Linear Collider (CLIC) is based on a two-beam acceleration scheme. The energy of two high-intensity, low-energy drive beams is extracted and transferred to two low-intensity, high-energy main beams. The machine protection and electrical integrity group has the mission to protect the various machine components from damage caused by ill controlled beams. Various failure scenarios were studied and the potential damage these failures could cause to the machine structures were estimated. In this paper, first results of the beam response to correctors and/or quadrupole kick failures in the main linac and in the beam delivery system (BDS) sections are presented as well as possible collimator damage scenarios. The use of the code PLACET for machine protection analysis is described as well.