IPAC2011 - List of Keywords (betatron)

Paper	Title	Other Keywords	Page
MOPO005	A Transverse Feedback System using Multiple Pickups for Noise Minimization	kicker, pick-up, synchrotron, feedback	487
	M. Alhumaidi, A.M. Zoubir TU Darmstadt, Darmstadt, Germany
	A new concept for using multiple pickups for estimating beam angle at the kicker is addressed. The estimated signal should be the driving feedback signal. The signals from the different pickups are delayed, such that they correspond to the same bunch. Consequently a weighted sum of the delayed signals is suggested as an estimator of the beam angle at the kicker. The weighting coefficients are calculated such that the estimator is unbiased, i.e. the output corresponds to the actual beam angle at the kicker for non-noisy pickup signals. Furthermore, the estimator must give the minimal noise power at the output among all linear unbiased estimators. Finally results for the heavy ions synchrotron SIS 18 at the GSI are shown.

MOPO013	Suppression of Emittance Growth by Excited Magnet Noise with the Transverse Damper in LHC in Simulations and Experiment	pick-up, feedback, emittance, simulation	508
	W. Höfle, G. Arduini, R. De Maria, G. Kotzian, D. Valuch CERN, Geneva, Switzerland V.A. Lebedev Fermilab, Batavia, USA
	The LHC transverse dampers initially build to control transverse instabilities are also a good remedy to suppress the oscillations causing emittance growth excited by electro-magnetic noises at the frequencies of betatron sidebands. To prevent the emittance growth excited by magnet noise using the damper this system has to have extremely low noise properties. The paper discusses simulation results on the effectiveness of the transverse feedback system to suppress such oscillations and the experimental results from a damper point of view as they were gained during the 2010 LHC run. Possible improvements in the damper system to enhance its effectiveness with respect to the suppression of emittance blow-up are also discussed.

MOPS052	Analytical and Numerical Calculations of Beam Pipe Impedances at Low Frequencies with Application to Thin SIS100 Pipe	impedance, coupling, synchrotron, shielding	721
	U. Niedermayer, O. Boine-Frankenheim, L. Hänichen TEMF, TU Darmstadt, Darmstadt, Germany
	The projected fast ramped synchrotron SIS100 for FAIR uses an elliptical stainless steel beam pipe of 0.3 mm thickness. The lowest coherent betatron sidebands reach down to 100 kHz which demands accurate impedance calculations in the low frequency (LF) regime. For these frequencies, i.e. skin depth greater than wall thickness, structures behind the pipe may contribute to the impedance. Due to the extremely large wake length numerical methods in the time domain are not applicable. The longitudinal and transverse impedance of the thin SIS100 beam pipe including structures behind the pipe are obtained numerically by a method using power loss in the frequency domain. We compare different analytical models for simplified pipe structures to the numerical results. The dc and ultra-relativistic limits are investigated. The interpretation of bench measurements in the LF regime is discussed.

MOPS084	Status of Electron Cloud Dynamics Measurements at CESRTA*	dipole, electron, damping, feedback	799
	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: Supported by US National Science Foundation (PHY-0734867) & Dept. of Energy (DE-FC02-08ER41538) The study of electron cloud-related instabilities for the CESR-TA project permits the observation of the interaction of the electron cloud with the stored beam under a variety of accelerator conditions. These measurements are undertaken utilizing automatic and semi-automatic techniques for three basic observations: the measurement of tune shifts of individual bunches along a train, the detection of the coherent self-excited spectrum for each bunch within a train and the pulsed excitation of either the betatron dipole or head-tail mode for each individual bunch within the train, followed by the observation of the damping of its coherent motion. These techniques are employed to study the electron cloud-related interactions in a number of conditions, such as trains of bunches with low emittance and spaced by as little as 4 nsec between bunches. We report on the most recent observations and results.

MOPS088	Simulation of Electron Cloud Beam Dynamics for CesrTA	emittance, simulation, electron, positron	808
	K.G. Sonnad, G. Dugan, M.A. Palmer, G. Ramirez, H.A. Williams CLASSE, Ithaca, New York, USA K.R. Butler Cornell University, Ithaca, New York, USA M.T.F. Pivi SLAC, Menlo Park, California, USA
	This presentation provides a comprehensive set of results obtained using the simulation program CMAD. CMAD is being used for studying electron cloud induced beam dynamics issues for CesrTA, which is a test facility for studying physics associated with electron and positron damping rings. In particular, we take a closer look at electron cloud induced effects on positron beams, including head-tail motion, emittance growth and incoherent tune shifts for parameters specific to ongoing experimental studies at CesrTA. The correspondence between simulation and experimental results will also be discussed. Work supported by US Department of Energy grant number DE-FC02-08ER41538 and the National Science Foundation grant number PHY-0734867

TUPC103	Monitoring of the Betatron Tune and Amplitude at Multi-batch Injection of J-PARC MR	injection, kicker, feedback, quadrupole	1254
	S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan M. Takagi Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan M. Tejima, T. Toyama KEK, Ibaraki, Japan
	The beam power of J-PARC Main Ring Synchrotron (MR) increased gradually from 2008, and came to be able regularly to supply the beam of 145kW February, 2011. Many of current beam losses are localized to the collimator located on the injection section. One of the problems of the beam injection is that the orbit of the beam transportation line is unstable. It causes sometimes large transverse injection error. Because the transverse injection error is essentially proportional to the amplitude of the betatron oscillation, it is possible to observe by measuring the turn-by-turn position for every bunch of injected beam by using BPMs located on the injection section. In this report, it is described the method how to measure injection error from beam position. It is also discussed about the effect of reflection wave of injection kicker magnets.

TUPC110	Ultrashort Bunch Train Longitudinal Diagnostics using RF Deflecting Structure	cavity, diagnostics, laser, emittance	1275
	Y. Yang, H. Chen, Y.-C. Du, W.-H. Huang, C. Li, L.X. Yan TUB, Beijing, People's Republic of China
	Ultrashort electron bunch train has been produced using UV laser stacking in Tsinghua University. With an S-band deflecting cavity inserted into the Tsinghua Thomson Scattering beamline, it is possible to characterize the bunch train longitudinal property. This paper briefly introduced the measurement layout in our lab and reported the recent experiment results, including bunch train profile measurement and longitudinal phase space. The main sources of error are also discussed.

TUPC117	Embedded EPICS IOC Data Acquisition System for Beam Instability Research	feedback, wakefield, EPICS, storage-ring	1290
	N. Zhang, Y.B. Leng SSRF, Shanghai, People's Republic of China
	Funding: This research is supported by National Natural Science Fund(No.Y155131061). To be a part of beam diagnostics system in SSRF 3.5 GeV electron storage ring, a high performance oscilloscope is introduced to build a bunch by bunch data acquisition and processing dedicated system, which is mainly used to observe individual bunch position in transverse plane and bunch charge. By analysis of Betatron oscillation amplitude distribution and corresponding filling pattern, we hope to find phenomenon about multi-bunch Wakefield effect[1] on beam Betatron oscillation for beam instability research. The system is configured as a scope IOC, and integrated into the EPICS based control system. Application of this system and some data analysis results are also discussed in this paper.

TUPO033	Emittance Minimization by Courant-Snyder Parameter Scan in Merger Section at the Compact Energy Recovery Linear Accelerator.	emittance, space-charge, SRF, dipole	1506
	J.G. Hwang Kyungpook National University, Daegu, Republic of Korea E.-S. Kim KNU, Deagu, Republic of Korea T. Miyajima KEK, Tsukuba, Japan
	The project of compact-Energy Recovery Linac(c-ERL) at Photon Factory in KEK is a test facility for the 5 GeV ERL, which is one of the candidates of next generation light source. It consists of injector system, merger section, main SRF section, return arc, long straight section and beam dump. The injector system produces beams with a low-energy of 5 MeV and low-emittance less than 1 mm-mrad. It causes the large emittance growth by space charge force in merger section, which consists of two rectangular type dipole magnets and one sector type magnet. Dispersion also causes the displacement of bunch sllice on horizontal plane. The displacement of bunch slice is laid on the kick angle induced by space charge force. Also, each slice has the orientation of the phase ellipse on horizontal phase space. Therefore, the emittance growth due to the displacement of bunch sllice induced by space charge force in the horizontal phase space can be minimized by matching the displacement to the orientation of the phase ellipse at the exit of merger. We present the results of the emittance minimization performed by mathcing of the angle of the phase ellipse by scan of CS (Courant-Snyder) parameter.

TUPZ005	Design of the NICA Collider Rings	collider, luminosity, ion, lattice	1807
	O.S. Kozlov, H.G. Khodzhibagiyan, S.A. Kostromin, I.N. Meshkov, A.O. Sidorin, N.D. Topilin, G.V. Trubnikov JINR, Dubna, Moscow Region, Russia
	The Nuclotron-based Ion Collider fAcility (NICA) is a new accelerator complex being constructed at JINR aimed to provide the collider experiments with ion-ion (Au⁷⁹⁺) and ion-proton collisions at the energy range of 1-4.5 GeV/n and also the collisions of polarized proton-proton and deuteron-deuteron beams. Superconducting collider rings accumulate beam injected from Nuclotron and realize the conditions for beam-beam interactions to achieve the required luminosity. Each ring has the racetrack shape with two arcs and two long straight sections. Its circumference is about 500 m. The collider lattice design is subjected to have possibility of the gamma transition variation, mainly by the arcs retuning. The long straight sections contain the most of the insertion devices and are matched to the arcs, optimized to provide the final focusing of the beams in IP and accurate betatron tune adjustment.

TUPZ007	First Ion Collimation Commissioning Results at the LHC	ion, collimation, simulation, proton	1813
	G. Bellodi, R.W. Assmann, R. Bruce, M. Cauchi, J.M. Jowett, G. Valentino, D. Wollmann CERN, Geneva, Switzerland
	First commissioning of the LHC Pb ion beams to 1.38 A TeV energy was successfully achieved in November 2010. Ion collimation has been predicted to be less efficient than for protons at the LHC, because of the complexity of the physical processes involved: nuclear fragmentation and electromagnetic dissociation in the primary collimators creating fragments with a wide range of Z/A ratios, that are not intercepted by the secondary collimators but lost in the dispersion suppressor sections of the ring. In this article we present first comparisons of measured loss maps with theoretical predictions from simulation runs with the ICOSIM code. An extrapolation to define the ultimate intensity limit for Pb beams is attempted. The scope of possible improvements in collimation efficiency coming from the installation of new collimators in the cold dispersion suppressors and combined betatron and momentum cleaning is also explored.

TUPZ009	LHC Machine Protection against Very Fast Crab Cavity Failures	cavity, optics, luminosity, emittance	1816
	T. Baer, R. Tomás, J. Tückmantel, J. Wenninger, F. Zimmermann CERN, Geneva, Switzerland T. Baer Uni HH, Hamburg, Germany R. Calaga BNL, Upton, Long Island, New York, USA
	For the high-luminosity LHC upgrade program (HL-LHC), the installation of crab cavities (CCs) is essential to compensate the geometric luminosity loss due to the crossing angle. The baseline is a local scheme with CCs around the ATLAS and CMS experiments. In a failure case (e.g. a CC quench), the voltage and/or phase of a CC can change significantly with a fast time constant of the order of a LHC turn. This can lead to large, global betatron oscillations of the beam. Against the background of machine protection, the influence of a CC failure on the beam dynamics is discussed. The results from dedicated tracking studies, including the LHC upgrade optics, are presented. Necessary countermeasures to limit the impact of CC failures to an acceptable level are proposed.

WEZA01	Round Beam Collisions at VEPP-2000*	luminosity, positron, lattice, resonance	1926
	Y.M. Shatunov, D.E. Berkaev, A.N. Kirpotin, I. Koop, A.P. Lysenko, I. Nesterenko, E. Perevedentsev, Yu. A. Rogovsky, A.L. Romanov, P.Yu. Shatunov, D.B. Shwartz, A.N. Skrinsky, I. Zemlyansky BINP SB RAS, Novosibirsk, Russia
	The idea of round beams collision was proposed more than 20 years ago for the Novosibirsk Phi-factory design. It requires equal emittances, equal small fractional tunes, equal beta functions at the IP, no betatron coupling in the collider arcs. A 90° rotation at each passage of the transverse oscillation plane by means of solenoids in the interaction regions provides conservation of the longitudinal component of the angular moment. Thus the transverse motion becomes one-dimensional. Such a scheme helps to eliminate all betatron coupling resonances that are of crucial importance for beam-beam tune shift saturation and lifetime degradation. Only recently, the round beam concept was successfully tested at the electron-positron collider VEPP2000 at the energy of 510 MeV. Despite the low energy a high single bunch luminosity of 10³¹ cm^-2s⁻¹ was achieved together with a maximum tune shift as high as 0.1. At present the work is in progress to increase the energy of the collider to explore the range between 510 MeV and 1 GeV in collision.
	Slides WEZA01 [3.740 MB]

WEPC015	Tuning Methods for HIMAC Multiple-energy Operation	acceleration, resonance, beam-losses, synchrotron	2037
	K. Katagiri, T. Furukawa, Y. Iwata, K. Noda, S. Sato, T. Shirai NIRS, Chiba-shi, Japan K. Mizushima Chiba University, Graduate School of Science and Technology, Chiba, Japan E. Takeshita Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
	Beam stability of multiple-energy operation at HIMAC synchrotron was improved for the fast raster-scanning irradiation. In order to improve the transverse stability, the working point of the betatron tune was investigated during one operation cycle. The signals were collected from the beam position monitor using a fast data-acquisition unit. The temporal evolution of the horizontal and vertical betatron tune was evaluated by using the short time Fourier transform. Analyzed results showed that variation of the betatron tune in the acceleration interval passed through the 3rd-order coupling resonance line, and it caused undesirable emittance growth. In order to keep the working point within the desirable operating region, the current pattern of the power supplies for the quadrupole magnets was corrected by using the variation of the betatron tune. The experimental results showed that the working point could be successfully stabilized, and the undesirable beam losses could be reduced during the acceleration interval.

WEPC016	Amplitude Dependent Orbit Shift and its Effect on Beam Injection	injection, septum, sextupole, synchrotron	2040
	Y. Shoji LASTI, Hyogo, Japan T. Nakamura, J. Schimizu, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	The betatron oscillation amplitude dependent orbit shift was measured at the electron storage ring, NewSUBARU. The result roughly agreed with the theoretical calculation. The effect of this shift on the beam injection is discussed using parameters of NewSUBARU and SPring-8. Generally there exists a better side for the injection, the inner side or the outer side of the ring, which depends on the sign of the orbit shift at the injection septum. In case of the NewSUBARU, the beam is injected from the outer side and the shift is positive. The effective thickness of the septum is reduced by the large oscillation amplitude of the injected beam. On the other hand at SPring-8, the beam is injected from the inner side of the ring while the orbit shift is negative. This means that the two rings are using better side for the injection.

WEPC017	Vertical Beam Size Correction at the SSRF Storage Ring	coupling, quadrupole, emittance, simulation	2043
	M.Z. Zhang, J. Hou, B.C. Jiang, H.H. Li, S.Q. Tian SINAP, Shanghai, People's Republic of China
	Vertical beam size is an important parameter for 3rd generation light source. Correcting the vertical beam size is a realistic way to increase brightness or beam lifetime without any additional equipments in a machine under operation. The main sources of vertical beam size are betatron coupling and vertical dispersion. At the SSRF storage ring, LOCO is used for vertical dispersion and coupling measurements and corrections. The betatron coupling and vertical dispersion is corrected by skew quadrupoles that calculated by LOCO. Vertical beam size can be changed from 10s um to several um for different purposes. Touschek lifetime is also measured to testify the vertical beam size. Simulations show that if smaller vertical beam size is required, more skew quadrupoles are needed.

WEPC031	Optics Corrections at RHIC	optics, dipole, proton, quadrupole	2070
	G. Vanbavinckhove CERN, Geneva, Switzerland M. Bai, G. Robert-Demolaize BNL, Upton, Long Island, New York, USA
	Excessive beta-beat, deviation of measured beta function from the calculated beta functions based on an model, in high energy colliders can lead to large deviation of beta function at collision point as well as other adverse effects. The segment-by-segment technique was successfully demonstrated in the LHC operation for reducing the beta-beat. It was then applied to RHIC polarized proton operation in 2011. This paper reports the experimental results of optics correction at RHIC. Future plan is also presented.

WEPC033	Decoupling Problem of Weakly Linear Coupled Double Mini-beta-y Lattice of TPS Storage Ring	coupling, lattice, storage-ring, resonance	2076
	H.-P. Chang, C.C. Chiang, M.-S. Chiu NSRRC, Hsinchu, Taiwan
	Three double mini-beta-y (DMBy) lattice design of the TPS storage ring is in progress to enhance the photon sources at three of the six long straight sections. For the estimation of Touschek beam lifetime, the TRACY code is used to calculate the momentum acceptance of the linear coupled TPS 3-DMBy lattice. The weak linear coupling was generated by adding some random skew quadrupoles at all quadrupole locations in order to create 1% coupling. Using the Teng’s symplectic rotation form in program may cause trouble in decoupling the one-turn coupled matrix. This report describes how we solve this decoupling problem and some useful references and comments are also presented.

WEPC036	Coherent Synchrotron Radiation Source Based on an Isochronous Accumulator Ring with Femtosecond Electron Bunches	linac, gun, radiation, lattice	2085
	N.Y. Huang NTHU, Hsinchu, Taiwan H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, X. Li, F. Miyahara, T. Muto, K. Nanbu, Y. Tanaka Tohoku University, Research Center for Electron Photon Science, Sendai, Japan W.K. Lau NSRRC, Hsinchu, Taiwan
	A compact isochronous accumulator ring has been studied as a source of coherent synchrotron radiation (CSR) at a wavelength region from THz to GHz. Since the thermionic rf gun is substantially stable in general, we anticipate a bunch train of very short electron pulses can be provided satisfactorily by means of velocity bunching. Careful numerical simulations show possibility of the bunch length of much less than 100 fs with a bunch charge of 20 pC, which will contain sufficiently large form factor for production of CSR at the wavelengths longer than ~ 0.1 mm. The coherent THz radiation of high average power will be achieved if the short bunches can be circulated in the accumulator ring without bunch lengthening. This paper will describe the optimization of thermionic injector to produce femtosecond bunches in addition to study of the lattice designing of complete isochronous optics for the accumulator ring.

WEPC058	Field Properties of the ESR Magnets and their Influence on Beam Optics	dipole, quadrupole, sextupole, simulation	2148
	O.E. Gorda, C. Dimopoulou, A. Dolinskii, S.A. Litvinov, F. Nolden, M. Steck GSI, Darmstadt, Germany
	Machine experiments at the experimental storage ring (ESR) demonstrated that the ring acceptance is strongly restricted by field errors. Higher-order field harmonics of the dipole and quadrupole magnets have been calculated and then used in particle tracking simulations in order to find out the dynamic aperture of the ESR. To benchmark the results of numerical calculations, betatron tune measurements have been performed with a uranium beam at the energy of 400 MeV/u. The results of the magnetic field simulations for the ESR magnets and a comparison between the measured and calculated tune behavioгr are presented.

WEPC063	Apochromatic Twiss Parameters of Drift-quadrupole Systems with Symmetries	quadrupole, lattice, chromatic-effects, beam-transport	2163
	V. Balandin, R. Brinkmann, W. Decking, N. Golubeva DESY, Hamburg, Germany
	It was shown in , 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 investigate apochromatic Twiss parameters of periodic, mirror symmetric and other drift-quadrupole systems with symmetries. V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Apochromatic Beam Transport in Drift-Quadrupole Systems", Proc. IPAC'10, Kyoto, Japan (2010).

WEPC068	Amplitude Dependent Betatron Oscillation Center Shift by Non-linearity and Beam Instability Interlock	insertion, insertion-device, simulation, sextupole	2178
	T. Nakamura, K. Kobayashi, J. Schimizu, T. Seike, K. Soutome, M. Takao JASRI/SPring-8, Hyogo-ken, Japan T. Hara RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	The center of the betatron oscillation in storage rings shifts as the amplitude of the oscillation increases. This effect is produced by non-linear components like sextupole magnets with its first-order perturbation. This shift can be observed as the shift of the closed orbit with usual slow beam position monitor (BPM) for closed orbit measurement. At the SPring-8 storage ring, the insertion devices (IDs) have their dedicated BPMs for monitoring the beam axis in the IDs. If some amount of the shift of beam axis is observed, the beam is aborted to avoid the damage by the irradiation of the ring components by ID radiation. When a betatron oscillation is excited by a beam transverse instability, the beam axis also oscillates and might produce the damage. Though it is not easy to detect the oscillation amplitude in various bunch current and filling patterns like in SPring-8, the oscillation produces the shift of the center of the betatron oscillation and can be observed by the BPM of IDs, and the beam is aborted. Calculation, tracking simulation and observation will be reported.

WEPC069	Impact of Nonlinear Resonances on Beam Dynamics at the SPring-8 Storage Ring	injection, resonance, storage-ring, coupling	2181
	M. Takao, J. Schimizu, Y. Shimosaki, K. Soutome JASRI/SPring-8, Hyogo-ken, Japan
	For a low emittance storage ring like high brilliant light sources, the improvement of nonlinear beam dynamics is necessary for the stable operation, or for providing large dynamic aperture and momentum acceptance for efficient injection and long Touschek lifetime. At the SPring-8 storage ring it is observed that injection efficiency is affected by the gap heights of the magnet arrays of the in-vacuum insertion devices. The fact that the injected beam of fundamentally oscillating in horizontal direction is limited by the vertical aperture means that coupling resonances influence the beam dynamics. To clarify the phenomena, we studied the nonlinear beam dynamics of transverse betatron motion by means of turn-by-turn method. Then, we found some nonlinear coupling resonances, such as the one by skew sextupole field, are excited to enhance vertical oscillation and to deteriorate the injection efficiency. By analyzing these results, we developed measures to suppress the effect of the nonlinear coupling resonances and to improve the injection efficiency.

WEPC071	The Motion of an Electron in the Periodic Cusped Magnetic Fields	electron, wiggler, focusing, coupling	2184
	G. Du, B.L. Qian, H. Wang National University of Defense Technology, Changsha, Kaifu District, People's Republic of China
	Funding: National High Technology Research and Development Program of P. R. China The motion and its stability of an electron in the periodic cusped magnetic fields have been analyzed theoretically and calculated numerically, as the stability could not be well predicted by the Mathieu’s equation to guide the design of the magnetic focusing system for the propagation of the sheet electron beams in the waveguides. The precise solution to the motion equations of the electron has been obtained by iteration. To validate the analytical solution and to evaluate the stability of the motion, numerical calculations have been carried out. And the results show that the analytical solution is reliable, and there is only one stable region in the (p₀, B₀) space, where the parameter p₀ is the period of the magnetic fields, and B₀ is the magnitude of the magnetic fields. Besides, the stability of the electron motion would become weaker while the initial distance between the electron and the axis becomes larger. These results are interesting to the area of the sheet-electron-beam microwave sources focused by the periodical cusped magnetic fields.

WEPC072	Insertion Devices and Beam Dynamics in the PLS-II Storage Ring	wiggler, undulator, insertion, insertion-device	2187
	S. Chunjarean, S. Shin PAL, Pohang, Kyungbuk, Republic of Korea
	Effects of insertion devices like a superconducting multipole wiggler or an in-vacuum undulator on the beam dynamics of tghe upgraded Pohang Light Source (PLS-II) storage ring have been investigated. The narrow gap related to a short period length of the in-vacuum undulator or a transverse magnetic field roll off can impact the dynamic aperture or Touschek lifetime or injection efficiency. A three dimensional magnetic field model has been developed based on numerical data consisting of several coefficients in the Taylor expansion to accurately represent the actual field. In this paper, the magnetic field model has been produced with the differential algebraic code COSY INFINITY to formulate the Taylor transfer map for the wiggler and undulator. Frequency map analysis (FMA) and full 6D tracking has been performed to investigate resonances which may affect the particle stability and causing a reduction in injection efficiency.

WEPS007	CNAO Synchrotron Commissioning	synchrotron, extraction, pick-up, proton	2496
	C. Priano, G. Balbinot, G. Bazzano, J. Bosser, E. Bressi, M. Caldara, H. Caracciolo, L. Falbo, A. Parravicini, M. Pullia, C. Viviani CNAO Foundation, Milan, Italy C. Biscari, A. Ghigo INFN/LNF, Frascati (Roma), Italy
	The CNAO (National Center for Oncological Hadrontherapy), located in Pavia, is the first Italian center for deep hadrontherapy with proton and carbon ion beams. The CNAO synchrotron initial commissioning has been carried out using proton beams in the full range of energies: 60 to 250 MeV/u. The first foreseen treatments will need energies between 120 and 170 MeV/u. The nominal proton currents have been reached. The energy scaling of the synchrotron systems and parameters leads to an extracted energy that matches the measured particle range better than 0.1 mm, fitting the treatment requirements, with repeatable beam size and beam current in the treatment room at all investigated energies. A summary of the main results of the synchrotron commissioning is presented.

WEPS008	Operation Status and Future Plan of J-PARC Main Ring	extraction, beam-losses, kicker, linac	2499
	T. Koseki KEK, Ibaraki, Japan
	The J-PARC Main Ring (MR) has started users operation since 2009. The MR has two beam extraction systems. One is a fast extraction (FX) system for beam delivery to the neutrino beam line of the Tokai-to-Kamioka (T2K) experiment, and the other is a slow extraction (SX) system for beam delivery to the hadron experimental hall. For the T2K experiment, the maximum beam power of 145 kW is delivered continuously. For users of the hadron experimental hall, the beam power of 3 kW is delivered with extraction efficiency of 99.5%. In this paper, status of the high power beam operation of the MR is presented. Future prospect for increasing beam intensity is also discussed.

WEPS085	Deveopment of the IBA-JINR Cyclotron C235-V3 for Dmitrovgrad Hospital Center of the Proton Therapy	proton, cyclotron, extraction, septum	2706
	E. Syresin, G.A. Karamysheva, M.Y. Kazarinov, S.A. Kostromin, N.A. Morozov, A.G. Olshevsky, V.M. Romanov, E. Samsonov, N.G. Shakun, G. Shirkov, S.G. Shirkov JINR, Dubna, Moscow Region, Russia M. Abs, A. Blondin, P. Cahay, Y. Jongen, W.J.G.M. Kleeven, S. Zaremba IBA, Louvain-la-Neuve, Belgium
	The approval of the Dmitrovgrad project - the first Russian hospital center of the proton therapy was announced in 2010. The JINR-IBA collaboration have developed and constructed the proton cyclotron C235-V3 for this center. We plan to assemble this cyclotron in JINR in 2011 and perform tests with the extracted proton beam in 2012. This cyclotron is an essentially modified version of IBA C235 cyclotron. Modification of the extraction system is aim of new C235-V3 cyclotron. The new extraction system was constructed and tested. The experimentally measured extraction efficiency was improved from 60% for the old system to 77% for the new one. The new field mapping system was developed for the C235-V3 cyclotron. It system consists of the axial field mapping system and an additional system applied for radial field Br measurements. One of the goals of the cyclotron improvement is the modification of the sector spiral angle for reducing of coherent beam losses at acceleration. The coherent beam displacement from the median plane is defined by the vertical betatron tune Qz. An increase of the vertical betatron tune permits to reduce the coherent losses at proton acceleration.

WEPZ009	Parametric-Resonance Ionization Cooling in Twin-Helix	resonance, quadrupole, simulation, multipole	2784
	V.S. Morozov, Y.S. Derbenev JLAB, Newport News, Virginia, USA A. Afanasev, 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. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/ G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

THPC061	Comparison of Linear Optics Correction Means at the SLS	optics, quadrupole, storage-ring, closed-orbit	3032
	M. Aiba, M. Böge, J.T.M. Chrin, N. Milas, T. Schilcher, A. Streun PSI, Villigen, Switzerland
	The experimental determination of linear optics is a fundamental prerequisite to achieving a high performance storage ring. In order to further enhance SLS performance and to simulataneously reveal the limitations of the various techniques, we perform a systematic study of linear optics optimization using various independent methods. These include an analysis of the orbit reponse (LOCO), turn-by-turn data, and the response of the tune, whose correction is accomplished using the standard SLS procedure of varying the quadrupole strengths. A comparison of results from these procedures, which use fully independent observables, provides us with a valuable cross-check. For example, the betatron phase advances between BPMs, which is independent of BPM calibration, confirms the optics correction as determined from LOCO. The linear optics are hence better optimized, and these procedures, LOCO in particular, further serve to expose any previously hidden mis-calibration of parameters e.g. from BPMs and corrector magnets. Systematic errors from turn-by-turn data could also be vastly reduced by a better synchronization of the BPM triggers with the electron beam.

THPC062	SLS Vertical Emittance Tuning	alignment, quadrupole, coupling, emittance	3035
	M. Böge, M. Aiba, N. Milas, A. Streun PSI, Villigen, Switzerland S.M. Liuzzo INFN/LNF, Frascati (Roma), Italy
	To establish ultra-small vertical emittances (<1pmrad @2.86GeV) is one important aim of future linear collider damping ring optimization studies* at the SLS. By utilizing various correction techniques the SLS is already close to this goal with emittances of <2pm.rad @2.4GeV under the constraint of maintaining user operation conditions. One of the limiting contributions is the remaining spurious vertical dispersion eta_y of ~1.4mm which can be reduced by careful re-alignment and the application of dispersion-free steering techniques. The latter require orbit manipulations which are only partially compatible with the user operation mode. A first application of dispersion-free steering techniques demonstrates that eta_y can be reduced to <1mm at the expense of large orbit excursions which require a simultaneous betatron-coupling correction by means of skew quadrupoles in order to benefit in terms of a further reduction of vertical emittance. Therefore possible girder and magnet misalignments are analyzed in simulation which allows to localize the sources of eta_y and to eliminate them by re-alignment. Following this path the goal to achieve emittances close to 1pmrad is within reach. * In January 2011 the EU-project TIARA (Test Infrastructure and Accelerator Research Area) started with contributions from the SLS as part of the SVET (SLS Vertical Emittance Tuning) work package WP6.

THPC143	Beam-based Alignment for Injection Bump Magnets of the Storage Ring using Remote Tilt-control System	injection, alignment, controls, synchrotron	3221
	K. Fukami, K. Kobayashi, C. Mitsuda, T. Nakamura, K. Soutome JASRI/SPring-8, Hyogo-ken, Japan
	Stored beam is oscillated in vertical if the injection-bump magnets have alignment error in rotation around the beam-axis (tilt). In addition, even if the tilt is negligibly small, the beam out of the median plane is kicked in vertical direction. Also, there is a small long-term drift of the vertical beam positions in the bump magnets, which causes the gradual increase of the oscillation. We have already developed a remote tilt-control system to make a smooth realignment. To observe the oscillation, the beam position was measured bunch-by-bunch and turn-by-turn by using a bunch-by-bunch feedback system* with high resolution strip-line type beam position monitor. To obtain responses to the tilts of each magnet, the oscillations were measured under the condition that the magnets were tilted intentionally. Tilt errors were calculated with least-squares method using the responses. In order to confirm the source of the residual oscillation, a frequency analysis was carried out with FFT method using the position data from 1st to 128th turns. We succeeded in suppressing the vertical oscillation to sub-microns order, the value of less than one tenth of the beam size. * K. Fukami et al., Proc. of EPAC'08, p. 2172 (2008). ** T. Nakamura et al., Proc. of ICALEPCS'05, PO2.022-2 (2005).

THPO028	Upgrade Design of the Bump System in the J-PARC 3-GeV RCS	power-supply, injection, linac, resonance	3403
	T. Takayanagi, N. Hayashi, M. Kinsho, Y. Watanabe JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The 3-GeV RCS aims at providing at least 300 kW output beam power with the injection beam at 181 MeV. In the second stage, the upgrade of the LINAC beam energy to 400 MeV was funded and started in March 2009. This plan will be completed in 2012. Consequently, the 3-GeV RCS will aim at 1 MW beam power. The injection bump system of the RCS is composed of the shift bump-magnets, the horizontal paint bump-magnets and the vertical paint magnets.

THPS006	Present Status of Beam Cooling and Related Research at S-LSR	laser, electron, proton, ion	3436
	A. Noda, M. Nakao, H. Souda, H. Tongu Kyoto ICR, Uji, Kyoto, Japan T. Fujimoto, S.I. Iwata, S. Shibuya AEC, Chiba, Japan M. Grieser MPI-K, Heidelberg, Germany K. Ito, H. Okamoto HU/AdSM, Higashi-Hiroshima, Japan K. Jimbo Kyoto IAE, Kyoto, Japan K. Noda, T. Shirai NIRS, Chiba-shi, Japan
	Funding: Work supported by Advanced Compact Accelerator Development project of MEXT, and Global COE Program, "The Next Generation of Physics, Spun from Universality and Emergence" at Kyoto University. With the use of Ion Storage and Cooler Ring, S-LSR at ICR, Kyoto University, Mg ion beam with 40 keV has been laser cooled not only in the longitudinal direction but also in the horizontal direction by "Synchro-Betatron Coupling". Laser cooling is now tried to be extended to vertical direction with horizontal and vertical coupling with the use of a solenoid magnetic field. At S-LSR, an electron beam cooling is also applied for 7MeV proton beam, resulting an ordered state. Electron beam cooling is also applied for rf captured bunched beam and a short pulse proton beam with the duration of ~3 ns is fast extracted in order to enable beam irradiation. A beam course is now being constructed to irradiate bio-molecular cells vertically from the bottom through a thin film separating the accelerator vacuum from the cultivating liquid containing the cells in the air.

THPS008	Bucked Coils Lattice for the Neutrino Factory	lattice, cavity, emittance, factory	3439
	A. Alekou, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	In the Neutrino Factory muon front end, ionization cooling is used to reduce the very large initial transverse muon beam emittance. The current baseline cooling channel, FSIIA, performs well in simulations with respect to the transmission and cooling. However, recent studies indicate the RF voltage may be limited when external magnetic field is applied and therefore, as the FSIIA lattice has a large magnetic field at the position of the RF cavities, the feasibility of FSIIA may be questioned. Bucked Coils lattice, a new cooling lattice that uses different radius and opposite polarity coils placed at the same position along the beam-axis, aims to achieve low magnetic field at the position of the RF cavities while obtaining comparable transmission to FSIIA. The detailed comparison between FSIIA and different versions of the Bucked Coils configuration with respect to the magnetic field, beam dynamics and transmission are presented in this paper.

THPS029	Simulations of Various Driving Mechisms for the 3rd Order Resonant Extraction from the MedAustron Medical Synchrotron	extraction, lattice, synchrotron, resonance	3481
	G. Feldbauer, M. Benedikt CERN, Geneva, Switzerland U. Dorda EBG MedAustron, Wr. Neustadt, Austria
	The MedAustron medical synchrotron is based on the CERN-PIMMS design and its technical implementation by CNAO [1]. This document elaborates on studies performed on the baseline betatron-core driven extraction method and investigates the feasibility of alternative resonance driving mechanisms like RF-knockout, RF-noise and the lattice tune. Single particle tracking results are presented, explained and compared to analytical results. [1] M. Pullia, ‘‘Status Report on the Centro Nazionale di Adroterapia Oncologica (CNAO)'', 11th EPAC'08, Genoa, Itlay, June 2008, p. 982

THPS058	Third Integer Resonance Slow Extraction Using RFKO at High Space Charge.	extraction, resonance, dipole, space-charge	3559
	V.P. Nagaslaev, J.F. Amundson, J.A. Johnstone, C.S. Park, S.J. Werkema Fermilab, Batavia, USA
	A proposal to search for direct mu->e conversion at Fermilab requires slow, resonant extraction of an intense proton beam. Large space charge forces will present challenges, partly due to the substantial betatron tune spread. The main challenges will be maintaining a uniform spill shape and moderate losses at the septum. We propose to use "radio frequency knockout" (RFKO) for fine tuning the extraction. Strategies for the RFKO method will be discussed here in the context of the mu->e experiment. Feasibility of this method has been demonstrated using simulations.

THPS076	Sub-mm Therapeutic Carbon-Ion Irradiation Port in Gunma University	ion, lattice, linac, synchrotron	3607
	K. Torikai, T. Kanai, N.T. Nakano, H. Shimada, E. Takeshita, M. Tashiro, S. Yamada, K. Yusa Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan K. Hanakawa, T. Honda, K. Yoshida Mitsubishi Electric Corporation, Kobe, Japan
	Funding: This Study was done by Grant-in-Aid for Scientific Research (KAKENHI). One of advantage of particle therapy is concentration of irradiation dose. In April 2011, we developed "in-body-focusing type" irradiation port for "Proof-of-Principle" . This sub-mm port produces 1mm(1σ) beam. we will explain this irradion port at the conference.

THPZ017	Achromatic Low-beta Interaction Region Design for an Electron-ion Collider	electron, ion, sextupole, interaction-region	3723
	V.S. Morozov, Y.S. Derbenev JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by Muons, Inc. An achromatic Interaction Region (IR) design concept is presented with an emphasis on its application at an electron-ion collider. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the chromatic kick of the final focusing quadrupoles. Two such CCB’s placed symmetrically around an interaction point (IP) allow simultaneous compensation of the 1st-order chromaticities and chromatic beam smear at the IP without inducing significant 2nd-order aberrations. Special attention is paid to the difference in the electron and ion IR design requirements. We discuss geometric matching of the electron and ion IR footprints. We investigate limitations on the momentum acceptance in this IR design.

THPZ026	Collimation Dependent Beam Lifetime and Loss Rates in the LHC	collimation, luminosity, insertion, beam-losses	3744
	D. Wollmann, R.W. Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, G. Valentino CERN, Geneva, Switzerland
	The four primary collimators in each LHC beam define the smallest aperture. Particles with high betatron amplitudes or momentum offset will therefore hit first a primary collimator. The instantaneous particle loss rate at primary collimators is an important measure for the global lifetime of the beams and a major ingredient to identify collimation induced performance limitations in the LHC. These loss rates have been measured during a number of LHC fills, featuring both "good" fills with high luminosity and "bad" fills with beam instabilities. The beam lifetime at the collimators was then calculated from this data for different cases. The results are presented and interpreted within this paper.

THPZ028	Upgrade Studies for the LHC Collimators	collimation, alignment, proton, quadrupole	3750
	A. Rossi, R.W. Assmann, D. Wollmann CERN, Geneva, Switzerland
	The Phase-I LHC Collimation System has to be upgraded to work at high intensity and energy. Theoretical and engineering studies are focusing on different regions of the machine. The IR3 combined momentum and betatron cleaning, initially approved for installation, has presently been kept as fallback solution in case radiation to equipment limits LHC performance. The installation of collimators in the dispersion suppressor section DS3 has been delayed. In this paper we present predictions with matched optics and the effect of machine imperfections on the collimation performance with IR3 combined cleaning, with and without DS3 collimators.

THPZ032	Evaluation of the Combined Betatron and Momentum Cleaning in Point 3 in Terms of Cleaning Efficiency and Energy Deposition for the LHC Collimation Upgrade	collimation, quadrupole, beam-losses, proton	3762
	L. Lari, R.W. Assmann, V. Boccone, M. Brugger, F. Cerutti, A. Ferrari, A. Rossi, R. Versaci, V. Vlachoudis, D. Wollmann CERN, Geneva, Switzerland A. Faus-Golfe, L. Lari IFIC, Valencia, Spain A. Mereghetti UMAN, Manchester, United Kingdom
	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. The Phase I LHC Collimation System Upgrade could include moving part of the Betatron Cleaning from LHC Point 7 to Point 3 to improve both operation flexibility and intensity reach. In addition, the partial relocation of beam losses from the current Betatron cleaning region at Point 7 will mitigate the risks of Single Event Upsets to equipment installed in adjacent and partly not adequate shielded areas. A combined Betatron and Momentum Cleaning scenario at Point 3 implies the installation of new collimators and a new collimator aperture layout. This paper shows the whole LHC Collimator Efficiency variation with the new layout proposed at different beam energies. As part of the evaluation, energy deposition distribution in the IR3 region gives indications about the effect of this new implementation not only on the collimators themselves but also on the other beam line elements.

Paper

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MOPO005

A Transverse Feedback System using Multiple Pickups for Noise Minimization

kicker, pick-up, synchrotron, feedback

487

M. Alhumaidi, A.M. Zoubir
TU Darmstadt, Darmstadt, Germany

A new concept for using multiple pickups for estimating beam angle at the kicker is addressed. The estimated signal should be the driving feedback signal. The signals from the different pickups are delayed, such that they correspond to the same bunch. Consequently a weighted sum of the delayed signals is suggested as an estimator of the beam angle at the kicker. The weighting coefficients are calculated such that the estimator is unbiased, i.e. the output corresponds to the actual beam angle at the kicker for non-noisy pickup signals. Furthermore, the estimator must give the minimal noise power at the output among all linear unbiased estimators. Finally results for the heavy ions synchrotron SIS 18 at the GSI are shown.

MOPO013

Suppression of Emittance Growth by Excited Magnet Noise with the Transverse Damper in LHC in Simulations and Experiment

pick-up, feedback, emittance, simulation

508

W. Höfle, G. Arduini, R. De Maria, G. Kotzian, D. Valuch
CERN, Geneva, Switzerland
V.A. Lebedev
Fermilab, Batavia, USA

The LHC transverse dampers initially build to control transverse instabilities are also a good remedy to suppress the oscillations causing emittance growth excited by electro-magnetic noises at the frequencies of betatron sidebands. To prevent the emittance growth excited by magnet noise using the damper this system has to have extremely low noise properties. The paper discusses simulation results on the effectiveness of the transverse feedback system to suppress such oscillations and the experimental results from a damper point of view as they were gained during the 2010 LHC run. Possible improvements in the damper system to enhance its effectiveness with respect to the suppression of emittance blow-up are also discussed.

MOPS052

Analytical and Numerical Calculations of Beam Pipe Impedances at Low Frequencies with Application to Thin SIS100 Pipe

impedance, coupling, synchrotron, shielding

721

U. Niedermayer, O. Boine-Frankenheim, L. Hänichen
TEMF, TU Darmstadt, Darmstadt, Germany

The projected fast ramped synchrotron SIS100 for FAIR uses an elliptical stainless steel beam pipe of 0.3 mm thickness. The lowest coherent betatron sidebands reach down to 100 kHz which demands accurate impedance calculations in the low frequency (LF) regime. For these frequencies, i.e. skin depth greater than wall thickness, structures behind the pipe may contribute to the impedance. Due to the extremely large wake length numerical methods in the time domain are not applicable. The longitudinal and transverse impedance of the thin SIS100 beam pipe including structures behind the pipe are obtained numerically by a method using power loss in the frequency domain. We compare different analytical models for simplified pipe structures to the numerical results. The dc and ultra-relativistic limits are investigated. The interpretation of bench measurements in the LF regime is discussed.

MOPS084

Status of Electron Cloud Dynamics Measurements at CESRTA*

dipole, electron, damping, feedback

799

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: Supported by US National Science Foundation (PHY-0734867) & Dept. of Energy (DE-FC02-08ER41538)
The study of electron cloud-related instabilities for the CESR-TA project permits the observation of the interaction of the electron cloud with the stored beam under a variety of accelerator conditions. These measurements are undertaken utilizing automatic and semi-automatic techniques for three basic observations: the measurement of tune shifts of individual bunches along a train, the detection of the coherent self-excited spectrum for each bunch within a train and the pulsed excitation of either the betatron dipole or head-tail mode for each individual bunch within the train, followed by the observation of the damping of its coherent motion. These techniques are employed to study the electron cloud-related interactions in a number of conditions, such as trains of bunches with low emittance and spaced by as little as 4 nsec between bunches. We report on the most recent observations and results.

MOPS088

Simulation of Electron Cloud Beam Dynamics for CesrTA

emittance, simulation, electron, positron

808

K.G. Sonnad, G. Dugan, M.A. Palmer, G. Ramirez, H.A. Williams
CLASSE, Ithaca, New York, USA
K.R. Butler
Cornell University, Ithaca, New York, USA
M.T.F. Pivi
SLAC, Menlo Park, California, USA

This presentation provides a comprehensive set of results obtained using the simulation program CMAD. CMAD is being used for studying electron cloud induced beam dynamics issues for CesrTA, which is a test facility for studying physics associated with electron and positron damping rings. In particular, we take a closer look at electron cloud induced effects on positron beams, including head-tail motion, emittance growth and incoherent tune shifts for parameters specific to ongoing experimental studies at CesrTA. The correspondence between simulation and experimental results will also be discussed.
Work supported by US Department of Energy grant number DE-FC02-08ER41538
and the National Science Foundation grant number PHY-0734867

TUPC103

Monitoring of the Betatron Tune and Amplitude at Multi-batch Injection of J-PARC MR

injection, kicker, feedback, quadrupole

1254

S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan
M. Takagi
Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
M. Tejima, T. Toyama
KEK, Ibaraki, Japan

The beam power of J-PARC Main Ring Synchrotron (MR) increased gradually from 2008, and came to be able regularly to supply the beam of 145kW February, 2011. Many of current beam losses are localized to the collimator located on the injection section. One of the problems of the beam injection is that the orbit of the beam transportation line is unstable. It causes sometimes large transverse injection error. Because the transverse injection error is essentially proportional to the amplitude of the betatron oscillation, it is possible to observe by measuring the turn-by-turn position for every bunch of injected beam by using BPMs located on the injection section. In this report, it is described the method how to measure injection error from beam position. It is also discussed about the effect of reflection wave of injection kicker magnets.

TUPC110

Ultrashort Bunch Train Longitudinal Diagnostics using RF Deflecting Structure

cavity, diagnostics, laser, emittance

1275

Y. Yang, H. Chen, Y.-C. Du, W.-H. Huang, C. Li, L.X. Yan
TUB, Beijing, People's Republic of China

Ultrashort electron bunch train has been produced using UV laser stacking in Tsinghua University. With an S-band deflecting cavity inserted into the Tsinghua Thomson Scattering beamline, it is possible to characterize the bunch train longitudinal property. This paper briefly introduced the measurement layout in our lab and reported the recent experiment results, including bunch train profile measurement and longitudinal phase space. The main sources of error are also discussed.

TUPC117

Embedded EPICS IOC Data Acquisition System for Beam Instability Research

feedback, wakefield, EPICS, storage-ring

1290

N. Zhang, Y.B. Leng
SSRF, Shanghai, People's Republic of China

Funding: This research is supported by National Natural Science Fund(No.Y155131061).
To be a part of beam diagnostics system in SSRF 3.5 GeV electron storage ring, a high performance oscilloscope is introduced to build a bunch by bunch data acquisition and processing dedicated system, which is mainly used to observe individual bunch position in transverse plane and bunch charge. By analysis of Betatron oscillation amplitude distribution and corresponding filling pattern, we hope to find phenomenon about multi-bunch Wakefield effect[1] on beam Betatron oscillation for beam instability research. The system is configured as a scope IOC, and integrated into the EPICS based control system. Application of this system and some data analysis results are also discussed in this paper.

TUPO033

Emittance Minimization by Courant-Snyder Parameter Scan in Merger Section at the Compact Energy Recovery Linear Accelerator.

emittance, space-charge, SRF, dipole

1506

J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea
E.-S. Kim
KNU, Deagu, Republic of Korea
T. Miyajima
KEK, Tsukuba, Japan

The project of compact-Energy Recovery Linac(c-ERL) at Photon Factory in KEK is a test facility for the 5 GeV ERL, which is one of the candidates of next generation light source. It consists of injector system, merger section, main SRF section, return arc, long straight section and beam dump. The injector system produces beams with a low-energy of 5 MeV and low-emittance less than 1 mm-mrad. It causes the large emittance growth by space charge force in merger section, which consists of two rectangular type dipole magnets and one sector type magnet. Dispersion also causes the displacement of bunch sllice on horizontal plane. The displacement of bunch slice is laid on the kick angle induced by space charge force. Also, each slice has the orientation of the phase ellipse on horizontal phase space. Therefore, the emittance growth due to the displacement of bunch sllice induced by space charge force in the horizontal phase space can be minimized by matching the displacement to the orientation of the phase ellipse at the exit of merger. We present the results of the emittance minimization performed by mathcing of the angle of the phase ellipse by scan of CS (Courant-Snyder) parameter.

TUPZ005

Design of the NICA Collider Rings

collider, luminosity, ion, lattice

1807

O.S. Kozlov, H.G. Khodzhibagiyan, S.A. Kostromin, I.N. Meshkov, A.O. Sidorin, N.D. Topilin, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia

The Nuclotron-based Ion Collider fAcility (NICA) is a new accelerator complex being constructed at JINR aimed to provide the collider experiments with ion-ion (Au⁷⁹⁺) and ion-proton collisions at the energy range of 1-4.5 GeV/n and also the collisions of polarized proton-proton and deuteron-deuteron beams. Superconducting collider rings accumulate beam injected from Nuclotron and realize the conditions for beam-beam interactions to achieve the required luminosity. Each ring has the racetrack shape with two arcs and two long straight sections. Its circumference is about 500 m. The collider lattice design is subjected to have possibility of the gamma transition variation, mainly by the arcs retuning. The long straight sections contain the most of the insertion devices and are matched to the arcs, optimized to provide the final focusing of the beams in IP and accurate betatron tune adjustment.

TUPZ007

First Ion Collimation Commissioning Results at the LHC

ion, collimation, simulation, proton

1813

G. Bellodi, R.W. Assmann, R. Bruce, M. Cauchi, J.M. Jowett, G. Valentino, D. Wollmann
CERN, Geneva, Switzerland

First commissioning of the LHC Pb ion beams to 1.38 A TeV energy was successfully achieved in November 2010. Ion collimation has been predicted to be less efficient than for protons at the LHC, because of the complexity of the physical processes involved: nuclear fragmentation and electromagnetic dissociation in the primary collimators creating fragments with a wide range of Z/A ratios, that are not intercepted by the secondary collimators but lost in the dispersion suppressor sections of the ring. In this article we present first comparisons of measured loss maps with theoretical predictions from simulation runs with the ICOSIM code. An extrapolation to define the ultimate intensity limit for Pb beams is attempted. The scope of possible improvements in collimation efficiency coming from the installation of new collimators in the cold dispersion suppressors and combined betatron and momentum cleaning is also explored.

TUPZ009

LHC Machine Protection against Very Fast Crab Cavity Failures

cavity, optics, luminosity, emittance

1816

T. Baer, R. Tomás, J. Tückmantel, J. Wenninger, F. Zimmermann
CERN, Geneva, Switzerland
T. Baer
Uni HH, Hamburg, Germany
R. Calaga
BNL, Upton, Long Island, New York, USA

For the high-luminosity LHC upgrade program (HL-LHC), the installation of crab cavities (CCs) is essential to compensate the geometric luminosity loss due to the crossing angle. The baseline is a local scheme with CCs around the ATLAS and CMS experiments. In a failure case (e.g. a CC quench), the voltage and/or phase of a CC can change significantly with a fast time constant of the order of a LHC turn. This can lead to large, global betatron oscillations of the beam. Against the background of machine protection, the influence of a CC failure on the beam dynamics is discussed. The results from dedicated tracking studies, including the LHC upgrade optics, are presented. Necessary countermeasures to limit the impact of CC failures to an acceptable level are proposed.

WEZA01

Round Beam Collisions at VEPP-2000*

luminosity, positron, lattice, resonance

1926

Y.M. Shatunov, D.E. Berkaev, A.N. Kirpotin, I. Koop, A.P. Lysenko, I. Nesterenko, E. Perevedentsev, Yu. A. Rogovsky, A.L. Romanov, P.Yu. Shatunov, D.B. Shwartz, A.N. Skrinsky, I. Zemlyansky
BINP SB RAS, Novosibirsk, Russia

The idea of round beams collision was proposed more than 20 years ago for the Novosibirsk Phi-factory design. It requires equal emittances, equal small fractional tunes, equal beta functions at the IP, no betatron coupling in the collider arcs. A 90° rotation at each passage of the transverse oscillation plane by means of solenoids in the interaction regions provides conservation of the longitudinal component of the angular moment. Thus the transverse motion becomes one-dimensional. Such a scheme helps to eliminate all betatron coupling resonances that are of crucial importance for beam-beam tune shift saturation and lifetime degradation. Only recently, the round beam concept was successfully tested at the electron-positron collider VEPP2000 at the energy of 510 MeV. Despite the low energy a high single bunch luminosity of 10³¹ cm^-2s⁻¹ was achieved together with a maximum tune shift as high as 0.1. At present the work is in progress to increase the energy of the collider to explore the range between 510 MeV and 1 GeV in collision.

Slides WEZA01 [3.740 MB]

WEPC015

Tuning Methods for HIMAC Multiple-energy Operation

acceleration, resonance, beam-losses, synchrotron

2037

K. Katagiri, T. Furukawa, Y. Iwata, K. Noda, S. Sato, T. Shirai
NIRS, Chiba-shi, Japan
K. Mizushima
Chiba University, Graduate School of Science and Technology, Chiba, Japan
E. Takeshita
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan

Beam stability of multiple-energy operation at HIMAC synchrotron was improved for the fast raster-scanning irradiation. In order to improve the transverse stability, the working point of the betatron tune was investigated during one operation cycle. The signals were collected from the beam position monitor using a fast data-acquisition unit. The temporal evolution of the horizontal and vertical betatron tune was evaluated by using the short time Fourier transform. Analyzed results showed that variation of the betatron tune in the acceleration interval passed through the 3rd-order coupling resonance line, and it caused undesirable emittance growth. In order to keep the working point within the desirable operating region, the current pattern of the power supplies for the quadrupole magnets was corrected by using the variation of the betatron tune. The experimental results showed that the working point could be successfully stabilized, and the undesirable beam losses could be reduced during the acceleration interval.

WEPC016

Amplitude Dependent Orbit Shift and its Effect on Beam Injection

injection, septum, sextupole, synchrotron

2040

Y. Shoji
LASTI, Hyogo, Japan
T. Nakamura, J. Schimizu, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

The betatron oscillation amplitude dependent orbit shift was measured at the electron storage ring, NewSUBARU. The result roughly agreed with the theoretical calculation. The effect of this shift on the beam injection is discussed using parameters of NewSUBARU and SPring-8. Generally there exists a better side for the injection, the inner side or the outer side of the ring, which depends on the sign of the orbit shift at the injection septum. In case of the NewSUBARU, the beam is injected from the outer side and the shift is positive. The effective thickness of the septum is reduced by the large oscillation amplitude of the injected beam. On the other hand at SPring-8, the beam is injected from the inner side of the ring while the orbit shift is negative. This means that the two rings are using better side for the injection.

WEPC017

Vertical Beam Size Correction at the SSRF Storage Ring

coupling, quadrupole, emittance, simulation

2043

M.Z. Zhang, J. Hou, B.C. Jiang, H.H. Li, S.Q. Tian
SINAP, Shanghai, People's Republic of China

Vertical beam size is an important parameter for 3rd generation light source. Correcting the vertical beam size is a realistic way to increase brightness or beam lifetime without any additional equipments in a machine under operation. The main sources of vertical beam size are betatron coupling and vertical dispersion. At the SSRF storage ring, LOCO is used for vertical dispersion and coupling measurements and corrections. The betatron coupling and vertical dispersion is corrected by skew quadrupoles that calculated by LOCO. Vertical beam size can be changed from 10s um to several um for different purposes. Touschek lifetime is also measured to testify the vertical beam size. Simulations show that if smaller vertical beam size is required, more skew quadrupoles are needed.

WEPC031

Optics Corrections at RHIC

optics, dipole, proton, quadrupole

2070

G. Vanbavinckhove
CERN, Geneva, Switzerland
M. Bai, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Excessive beta-beat, deviation of measured beta function from the calculated beta functions based on an model, in high energy colliders can lead to large deviation of beta function at collision point as well as other adverse effects. The segment-by-segment technique was successfully demonstrated in the LHC operation for reducing the beta-beat. It was then applied to RHIC polarized proton operation in 2011. This paper reports the experimental results of optics correction at RHIC. Future plan is also presented.

WEPC033

Decoupling Problem of Weakly Linear Coupled Double Mini-beta-y Lattice of TPS Storage Ring

coupling, lattice, storage-ring, resonance

2076

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

Three double mini-beta-y (DMBy) lattice design of the TPS storage ring is in progress to enhance the photon sources at three of the six long straight sections. For the estimation of Touschek beam lifetime, the TRACY code is used to calculate the momentum acceptance of the linear coupled TPS 3-DMBy lattice. The weak linear coupling was generated by adding some random skew quadrupoles at all quadrupole locations in order to create 1% coupling. Using the Teng’s symplectic rotation form in program may cause trouble in decoupling the one-turn coupled matrix. This report describes how we solve this decoupling problem and some useful references and comments are also presented.

WEPC036

Coherent Synchrotron Radiation Source Based on an Isochronous Accumulator Ring with Femtosecond Electron Bunches

linac, gun, radiation, lattice

2085

N.Y. Huang
NTHU, Hsinchu, Taiwan
H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, X. Li, F. Miyahara, T. Muto, K. Nanbu, Y. Tanaka
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
W.K. Lau
NSRRC, Hsinchu, Taiwan

A compact isochronous accumulator ring has been studied as a source of coherent synchrotron radiation (CSR) at a wavelength region from THz to GHz. Since the thermionic rf gun is substantially stable in general, we anticipate a bunch train of very short electron pulses can be provided satisfactorily by means of velocity bunching. Careful numerical simulations show possibility of the bunch length of much less than 100 fs with a bunch charge of 20 pC, which will contain sufficiently large form factor for production of CSR at the wavelengths longer than ~ 0.1 mm. The coherent THz radiation of high average power will be achieved if the short bunches can be circulated in the accumulator ring without bunch lengthening. This paper will describe the optimization of thermionic injector to produce femtosecond bunches in addition to study of the lattice designing of complete isochronous optics for the accumulator ring.

WEPC058

Field Properties of the ESR Magnets and their Influence on Beam Optics

dipole, quadrupole, sextupole, simulation

2148

O.E. Gorda, C. Dimopoulou, A. Dolinskii, S.A. Litvinov, F. Nolden, M. Steck
GSI, Darmstadt, Germany

Machine experiments at the experimental storage ring (ESR) demonstrated that the ring acceptance is strongly restricted by field errors. Higher-order field harmonics of the dipole and quadrupole magnets have been calculated and then used in particle tracking simulations in order to find out the dynamic aperture of the ESR. To benchmark the results of numerical calculations, betatron tune measurements have been performed with a uranium beam at the energy of 400 MeV/u. The results of the magnetic field simulations for the ESR magnets and a comparison between the measured and calculated tune behavioгr are presented.

WEPC063

Apochromatic Twiss Parameters of Drift-quadrupole Systems with Symmetries

quadrupole, lattice, chromatic-effects, beam-transport

2163

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

It was shown in *, 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 investigate apochromatic Twiss parameters of periodic, mirror symmetric and other drift-quadrupole systems with symmetries.
* V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Apochromatic Beam Transport in Drift-Quadrupole Systems", Proc. IPAC'10, Kyoto, Japan (2010).

WEPC068

Amplitude Dependent Betatron Oscillation Center Shift by Non-linearity and Beam Instability Interlock

insertion, insertion-device, simulation, sextupole

2178

T. Nakamura, K. Kobayashi, J. Schimizu, T. Seike, K. Soutome, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan
T. Hara
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

The center of the betatron oscillation in storage rings shifts as the amplitude of the oscillation increases. This effect is produced by non-linear components like sextupole magnets with its first-order perturbation. This shift can be observed as the shift of the closed orbit with usual slow beam position monitor (BPM) for closed orbit measurement. At the SPring-8 storage ring, the insertion devices (IDs) have their dedicated BPMs for monitoring the beam axis in the IDs. If some amount of the shift of beam axis is observed, the beam is aborted to avoid the damage by the irradiation of the ring components by ID radiation. When a betatron oscillation is excited by a beam transverse instability, the beam axis also oscillates and might produce the damage. Though it is not easy to detect the oscillation amplitude in various bunch current and filling patterns like in SPring-8, the oscillation produces the shift of the center of the betatron oscillation and can be observed by the BPM of IDs, and the beam is aborted. Calculation, tracking simulation and observation will be reported.

WEPC069

Impact of Nonlinear Resonances on Beam Dynamics at the SPring-8 Storage Ring

injection, resonance, storage-ring, coupling

2181

M. Takao, J. Schimizu, Y. Shimosaki, K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan

For a low emittance storage ring like high brilliant light sources, the improvement of nonlinear beam dynamics is necessary for the stable operation, or for providing large dynamic aperture and momentum acceptance for efficient injection and long Touschek lifetime. At the SPring-8 storage ring it is observed that injection efficiency is affected by the gap heights of the magnet arrays of the in-vacuum insertion devices. The fact that the injected beam of fundamentally oscillating in horizontal direction is limited by the vertical aperture means that coupling resonances influence the beam dynamics. To clarify the phenomena, we studied the nonlinear beam dynamics of transverse betatron motion by means of turn-by-turn method. Then, we found some nonlinear coupling resonances, such as the one by skew sextupole field, are excited to enhance vertical oscillation and to deteriorate the injection efficiency. By analyzing these results, we developed measures to suppress the effect of the nonlinear coupling resonances and to improve the injection efficiency.

WEPC071

The Motion of an Electron in the Periodic Cusped Magnetic Fields

electron, wiggler, focusing, coupling

2184

G. Du, B.L. Qian, H. Wang
National University of Defense Technology, Changsha, Kaifu District, People's Republic of China

Funding: National High Technology Research and Development Program of P. R. China
The motion and its stability of an electron in the periodic cusped magnetic fields have been analyzed theoretically and calculated numerically, as the stability could not be well predicted by the Mathieu’s equation to guide the design of the magnetic focusing system for the propagation of the sheet electron beams in the waveguides. The precise solution to the motion equations of the electron has been obtained by iteration. To validate the analytical solution and to evaluate the stability of the motion, numerical calculations have been carried out. And the results show that the analytical solution is reliable, and there is only one stable region in the (p₀, B₀) space, where the parameter p₀ is the period of the magnetic fields, and B₀ is the magnitude of the magnetic fields. Besides, the stability of the electron motion would become weaker while the initial distance between the electron and the axis becomes larger. These results are interesting to the area of the sheet-electron-beam microwave sources focused by the periodical cusped magnetic fields.

WEPC072

Insertion Devices and Beam Dynamics in the PLS-II Storage Ring

wiggler, undulator, insertion, insertion-device

2187

S. Chunjarean, S. Shin
PAL, Pohang, Kyungbuk, Republic of Korea

Effects of insertion devices like a superconducting multipole wiggler or an in-vacuum undulator on the beam dynamics of tghe upgraded Pohang Light Source (PLS-II) storage ring have been investigated. The narrow gap related to a short period length of the in-vacuum undulator or a transverse magnetic field roll off can impact the dynamic aperture or Touschek lifetime or injection efficiency. A three dimensional magnetic field model has been developed based on numerical data consisting of several coefficients in the Taylor expansion to accurately represent the actual field. In this paper, the magnetic field model has been produced with the differential algebraic code COSY INFINITY to formulate the Taylor transfer map for the wiggler and undulator. Frequency map analysis (FMA) and full 6D tracking has been performed to investigate resonances which may affect the particle stability and causing a reduction in injection efficiency.

WEPS007

CNAO Synchrotron Commissioning

synchrotron, extraction, pick-up, proton

2496

C. Priano, G. Balbinot, G. Bazzano, J. Bosser, E. Bressi, M. Caldara, H. Caracciolo, L. Falbo, A. Parravicini, M. Pullia, C. Viviani
CNAO Foundation, Milan, Italy
C. Biscari, A. Ghigo
INFN/LNF, Frascati (Roma), Italy

The CNAO (National Center for Oncological Hadrontherapy), located in Pavia, is the first Italian center for deep hadrontherapy with proton and carbon ion beams. The CNAO synchrotron initial commissioning has been carried out using proton beams in the full range of energies: 60 to 250 MeV/u. The first foreseen treatments will need energies between 120 and 170 MeV/u. The nominal proton currents have been reached. The energy scaling of the synchrotron systems and parameters leads to an extracted energy that matches the measured particle range better than 0.1 mm, fitting the treatment requirements, with repeatable beam size and beam current in the treatment room at all investigated energies. A summary of the main results of the synchrotron commissioning is presented.

WEPS008

Operation Status and Future Plan of J-PARC Main Ring

extraction, beam-losses, kicker, linac

2499

T. Koseki
KEK, Ibaraki, Japan

The J-PARC Main Ring (MR) has started users operation since 2009. The MR has two beam extraction systems. One is a fast extraction (FX) system for beam delivery to the neutrino beam line of the Tokai-to-Kamioka (T2K) experiment, and the other is a slow extraction (SX) system for beam delivery to the hadron experimental hall. For the T2K experiment, the maximum beam power of 145 kW is delivered continuously. For users of the hadron experimental hall, the beam power of 3 kW is delivered with extraction efficiency of 99.5%. In this paper, status of the high power beam operation of the MR is presented. Future prospect for increasing beam intensity is also discussed.

WEPS085

Deveopment of the IBA-JINR Cyclotron C235-V3 for Dmitrovgrad Hospital Center of the Proton Therapy

proton, cyclotron, extraction, septum

2706

E. Syresin, G.A. Karamysheva, M.Y. Kazarinov, S.A. Kostromin, N.A. Morozov, A.G. Olshevsky, V.M. Romanov, E. Samsonov, N.G. Shakun, G. Shirkov, S.G. Shirkov
JINR, Dubna, Moscow Region, Russia
M. Abs, A. Blondin, P. Cahay, Y. Jongen, W.J.G.M. Kleeven, S. Zaremba
IBA, Louvain-la-Neuve, Belgium

The approval of the Dmitrovgrad project - the first Russian hospital center of the proton therapy was announced in 2010. The JINR-IBA collaboration have developed and constructed the proton cyclotron C235-V3 for this center. We plan to assemble this cyclotron in JINR in 2011 and perform tests with the extracted proton beam in 2012. This cyclotron is an essentially modified version of IBA C235 cyclotron. Modification of the extraction system is aim of new C235-V3 cyclotron. The new extraction system was constructed and tested. The experimentally measured extraction efficiency was improved from 60% for the old system to 77% for the new one. The new field mapping system was developed for the C235-V3 cyclotron. It system consists of the axial field mapping system and an additional system applied for radial field Br measurements. One of the goals of the cyclotron improvement is the modification of the sector spiral angle for reducing of coherent beam losses at acceleration. The coherent beam displacement from the median plane is defined by the vertical betatron tune Qz. An increase of the vertical betatron tune permits to reduce the coherent losses at proton acceleration.

WEPZ009

Parametric-Resonance Ionization Cooling in Twin-Helix

resonance, quadrupole, simulation, multipole

2784

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA
A. Afanasev, 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. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/ G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

THPC061

Comparison of Linear Optics Correction Means at the SLS

optics, quadrupole, storage-ring, closed-orbit

3032

M. Aiba, M. Böge, J.T.M. Chrin, N. Milas, T. Schilcher, A. Streun
PSI, Villigen, Switzerland

The experimental determination of linear optics is a fundamental prerequisite to achieving a high performance storage ring. In order to further enhance SLS performance and to simulataneously reveal the limitations of the various techniques, we perform a systematic study of linear optics optimization using various independent methods. These include an analysis of the orbit reponse (LOCO), turn-by-turn data, and the response of the tune, whose correction is accomplished using the standard SLS procedure of varying the quadrupole strengths. A comparison of results from these procedures, which use fully independent observables, provides us with a valuable cross-check. For example, the betatron phase advances between BPMs, which is independent of BPM calibration, confirms the optics correction as determined from LOCO. The linear optics are hence better optimized, and these procedures, LOCO in particular, further serve to expose any previously hidden mis-calibration of parameters e.g. from BPMs and corrector magnets. Systematic errors from turn-by-turn data could also be vastly reduced by a better synchronization of the BPM triggers with the electron beam.

THPC062

SLS Vertical Emittance Tuning

alignment, quadrupole, coupling, emittance

3035

M. Böge, M. Aiba, N. Milas, A. Streun
PSI, Villigen, Switzerland
S.M. Liuzzo
INFN/LNF, Frascati (Roma), Italy

To establish ultra-small vertical emittances (<1pmrad @2.86GeV) is one important aim of future linear collider damping ring optimization studies* at the SLS. By utilizing various correction techniques the SLS is already close to this goal with emittances of <2pm.rad @2.4GeV under the constraint of maintaining user operation conditions. One of the limiting contributions is the remaining spurious vertical dispersion eta_y of ~1.4mm which can be reduced by careful re-alignment and the application of dispersion-free steering techniques. The latter require orbit manipulations which are only partially compatible with the user operation mode. A first application of dispersion-free steering techniques demonstrates that eta_y can be reduced to <1mm at the expense of large orbit excursions which require a simultaneous betatron-coupling correction by means of skew quadrupoles in order to benefit in terms of a further reduction of vertical emittance. Therefore possible girder and magnet misalignments are analyzed in simulation which allows to localize the sources of eta_y and to eliminate them by re-alignment. Following this path the goal to achieve emittances close to 1pmrad is within reach.
* In January 2011 the EU-project TIARA (Test Infrastructure and Accelerator Research Area) started with contributions from the SLS as part of the SVET (SLS Vertical Emittance Tuning) work package WP6.

THPC143

Beam-based Alignment for Injection Bump Magnets of the Storage Ring using Remote Tilt-control System

injection, alignment, controls, synchrotron

3221

K. Fukami, K. Kobayashi, C. Mitsuda, T. Nakamura, K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan

Stored beam is oscillated in vertical if the injection-bump magnets have alignment error in rotation around the beam-axis (tilt). In addition, even if the tilt is negligibly small, the beam out of the median plane is kicked in vertical direction. Also, there is a small long-term drift of the vertical beam positions in the bump magnets, which causes the gradual increase of the oscillation. We have already developed a remote tilt-control system to make a smooth realignment*. To observe the oscillation, the beam position was measured bunch-by-bunch and turn-by-turn by using a bunch-by-bunch feedback system** with high resolution strip-line type beam position monitor. To obtain responses to the tilts of each magnet, the oscillations were measured under the condition that the magnets were tilted intentionally. Tilt errors were calculated with least-squares method using the responses. In order to confirm the source of the residual oscillation, a frequency analysis was carried out with FFT method using the position data from 1st to 128th turns. We succeeded in suppressing the vertical oscillation to sub-microns order, the value of less than one tenth of the beam size.
* K. Fukami et al., Proc. of EPAC'08, p. 2172 (2008).
** T. Nakamura et al., Proc. of ICALEPCS'05, PO2.022-2 (2005).

THPO028

Upgrade Design of the Bump System in the J-PARC 3-GeV RCS

power-supply, injection, linac, resonance

3403

T. Takayanagi, N. Hayashi, M. Kinsho, Y. Watanabe
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3-GeV RCS aims at providing at least 300 kW output beam power with the injection beam at 181 MeV. In the second stage, the upgrade of the LINAC beam energy to 400 MeV was funded and started in March 2009. This plan will be completed in 2012. Consequently, the 3-GeV RCS will aim at 1 MW beam power. The injection bump system of the RCS is composed of the shift bump-magnets, the horizontal paint bump-magnets and the vertical paint magnets.

THPS006

Present Status of Beam Cooling and Related Research at S-LSR

laser, electron, proton, ion

3436

A. Noda, M. Nakao, H. Souda, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
T. Fujimoto, S.I. Iwata, S. Shibuya
AEC, Chiba, Japan
M. Grieser
MPI-K, Heidelberg, Germany
K. Ito, H. Okamoto
HU/AdSM, Higashi-Hiroshima, Japan
K. Jimbo
Kyoto IAE, Kyoto, Japan
K. Noda, T. Shirai
NIRS, Chiba-shi, Japan

Funding: Work supported by Advanced Compact Accelerator Development project of MEXT, and Global COE Program, "The Next Generation of Physics, Spun from Universality and Emergence" at Kyoto University.
With the use of Ion Storage and Cooler Ring, S-LSR at ICR, Kyoto University, Mg ion beam with 40 keV has been laser cooled not only in the longitudinal direction but also in the horizontal direction by "Synchro-Betatron Coupling". Laser cooling is now tried to be extended to vertical direction with horizontal and vertical coupling with the use of a solenoid magnetic field. At S-LSR, an electron beam cooling is also applied for 7MeV proton beam, resulting an ordered state. Electron beam cooling is also applied for rf captured bunched beam and a short pulse proton beam with the duration of ~3 ns is fast extracted in order to enable beam irradiation. A beam course is now being constructed to irradiate bio-molecular cells vertically from the bottom through a thin film separating the accelerator vacuum from the cultivating liquid containing the cells in the air.

THPS008

Bucked Coils Lattice for the Neutrino Factory

lattice, cavity, emittance, factory

3439

A. Alekou, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

In the Neutrino Factory muon front end, ionization cooling is used to reduce the very large initial transverse muon beam emittance. The current baseline cooling channel, FSIIA, performs well in simulations with respect to the transmission and cooling. However, recent studies indicate the RF voltage may be limited when external magnetic field is applied and therefore, as the FSIIA lattice has a large magnetic field at the position of the RF cavities, the feasibility of FSIIA may be questioned. Bucked Coils lattice, a new cooling lattice that uses different radius and opposite polarity coils placed at the same position along the beam-axis, aims to achieve low magnetic field at the position of the RF cavities while obtaining comparable transmission to FSIIA. The detailed comparison between FSIIA and different versions of the Bucked Coils configuration with respect to the magnetic field, beam dynamics and transmission are presented in this paper.

THPS029

Simulations of Various Driving Mechisms for the 3rd Order Resonant Extraction from the MedAustron Medical Synchrotron

extraction, lattice, synchrotron, resonance

3481

G. Feldbauer, M. Benedikt
CERN, Geneva, Switzerland
U. Dorda
EBG MedAustron, Wr. Neustadt, Austria

The MedAustron medical synchrotron is based on the CERN-PIMMS design and its technical implementation by CNAO [1]. This document elaborates on studies performed on the baseline betatron-core driven extraction method and investigates the feasibility of alternative resonance driving mechanisms like RF-knockout, RF-noise and the lattice tune. Single particle tracking results are presented, explained and compared to analytical results.
[1] M. Pullia, ‘‘Status Report on the Centro Nazionale di Adroterapia Oncologica (CNAO)'', 11th EPAC'08, Genoa, Itlay, June 2008, p. 982

THPS058

Third Integer Resonance Slow Extraction Using RFKO at High Space Charge.

extraction, resonance, dipole, space-charge

3559

V.P. Nagaslaev, J.F. Amundson, J.A. Johnstone, C.S. Park, S.J. Werkema
Fermilab, Batavia, USA

A proposal to search for direct mu->e conversion at Fermilab requires slow, resonant extraction of an intense proton beam. Large space charge forces will present challenges, partly due to the substantial betatron tune spread. The main challenges will be maintaining a uniform spill shape and moderate losses at the septum. We propose to use "radio frequency knockout" (RFKO) for fine tuning the extraction. Strategies for the RFKO method will be discussed here in the context of the mu->e experiment. Feasibility of this method has been demonstrated using simulations.

THPS076

Sub-mm Therapeutic Carbon-Ion Irradiation Port in Gunma University

ion, lattice, linac, synchrotron

3607

K. Torikai, T. Kanai, N.T. Nakano, H. Shimada, E. Takeshita, M. Tashiro, S. Yamada, K. Yusa
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
K. Hanakawa, T. Honda, K. Yoshida
Mitsubishi Electric Corporation, Kobe, Japan

Funding: This Study was done by Grant-in-Aid for Scientific Research (KAKENHI).
One of advantage of particle therapy is concentration of irradiation dose. In April 2011, we developed "in-body-focusing type" irradiation port for "Proof-of-Principle" . This sub-mm port produces 1mm(1σ) beam. we will explain this irradion port at the conference.

THPZ017

Achromatic Low-beta Interaction Region Design for an Electron-ion Collider

electron, ion, sextupole, interaction-region

3723

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by Muons, Inc.
An achromatic Interaction Region (IR) design concept is presented with an emphasis on its application at an electron-ion collider. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the chromatic kick of the final focusing quadrupoles. Two such CCB’s placed symmetrically around an interaction point (IP) allow simultaneous compensation of the 1st-order chromaticities and chromatic beam smear at the IP without inducing significant 2nd-order aberrations. Special attention is paid to the difference in the electron and ion IR design requirements. We discuss geometric matching of the electron and ion IR footprints. We investigate limitations on the momentum acceptance in this IR design.

THPZ026

Collimation Dependent Beam Lifetime and Loss Rates in the LHC

collimation, luminosity, insertion, beam-losses

3744

D. Wollmann, R.W. Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland

The four primary collimators in each LHC beam define the smallest aperture. Particles with high betatron amplitudes or momentum offset will therefore hit first a primary collimator. The instantaneous particle loss rate at primary collimators is an important measure for the global lifetime of the beams and a major ingredient to identify collimation induced performance limitations in the LHC. These loss rates have been measured during a number of LHC fills, featuring both "good" fills with high luminosity and "bad" fills with beam instabilities. The beam lifetime at the collimators was then calculated from this data for different cases. The results are presented and interpreted within this paper.

THPZ028

Upgrade Studies for the LHC Collimators

collimation, alignment, proton, quadrupole

3750

A. Rossi, R.W. Assmann, D. Wollmann
CERN, Geneva, Switzerland

The Phase-I LHC Collimation System has to be upgraded to work at high intensity and energy. Theoretical and engineering studies are focusing on different regions of the machine. The IR3 combined momentum and betatron cleaning, initially approved for installation, has presently been kept as fallback solution in case radiation to equipment limits LHC performance. The installation of collimators in the dispersion suppressor section DS3 has been delayed. In this paper we present predictions with matched optics and the effect of machine imperfections on the collimation performance with IR3 combined cleaning, with and without DS3 collimators.

THPZ032

Evaluation of the Combined Betatron and Momentum Cleaning in Point 3 in Terms of Cleaning Efficiency and Energy Deposition for the LHC Collimation Upgrade

collimation, quadrupole, beam-losses, proton

3762

L. Lari, R.W. Assmann, V. Boccone, M. Brugger, F. Cerutti, A. Ferrari, A. Rossi, R. Versaci, V. Vlachoudis, D. Wollmann
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain
A. Mereghetti
UMAN, Manchester, United Kingdom

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.
The Phase I LHC Collimation System Upgrade could include moving part of the Betatron Cleaning from LHC Point 7 to Point 3 to improve both operation flexibility and intensity reach. In addition, the partial relocation of beam losses from the current Betatron cleaning region at Point 7 will mitigate the risks of Single Event Upsets to equipment installed in adjacent and partly not adequate shielded areas. A combined Betatron and Momentum Cleaning scenario at Point 3 implies the installation of new collimators and a new collimator aperture layout. This paper shows the whole LHC Collimator Efficiency variation with the new layout proposed at different beam energies. As part of the evaluation, energy deposition distribution in the IR3 region gives indications about the effect of this new implementation not only on the collimators themselves but also on the other beam line elements.