05 Beam Dynamics and Electromagnetic Fields
D01 Beam Optics - Lattices, Correction Schemes, Transport
Paper Title Page
MOODB03 Capture and Transport of the Laser Accelerated Ion Beams for the LIGHT Project 59
 
  • S.G. Yaramyshev, W.A. Barth, I. Hofmann, A. Orzhekhovskaya
    GSI, Darmstadt, Germany
  • B. Zielbauer
    HIJ, Jena, Germany
 
  Funding: Work supported by EURATOM (IFK KiT Program) and HIC for FAIR
An impressive advantage of Laser Ion Sources is an extremely high beam brilliance. The LIGHT project (Laser Ion Generation, Handling and Transport) is dedicated to the production of protons (ions), accelerated up to 10 MeV by using the GSI PHELIX laser at GSI, and injected into a conventional accelerator. A successful experimental campaign stimulated further investigation of the focusing, transport and collimation of the high energy and high brilliance proton beam. In addition to the advanced codes, describing the very early expansion phase of the proton-electron cloud, the versatile multiparticle code DYNAMION was implemented to perform beam dynamics simulations for different possible transport lines. Potentially transport lines compraises magnetic quadrupole lenses and/or solenoids for transverse beam focusing. A bunch rotation rf cavity decreasing the energy spread of the protons was included into the simulations. The results of the beam dynamics simulations are presented, as well as benchmarking activities with other codes. Further developments of the experimental test stand and the different possibilities of its integration to the GSI accelerators chain are discussed.
 
slides icon Slides MOODB03 [2.185 MB]  
 
TUOAB01 Lattice Design of a Very Low-emittance Storage Ring for SPring-8-II 942
 
  • Y. Shimosaki, K.K. Kaneki, T. Nakamura, H. Ohkuma, J. Schimizu, K. Soutome, M. Takao
    JASRI/SPring-8, Hyogo-ken, Japan
 
  The design work for an upgrade project of the SPring-8, the SPring-8-II, is in progress. Its ultimate goal is to provide a superior brilliance of photons by reducing emittance of electrons until a diffraction limit. A multi-bend lattice has been adopted for the emittance reduction; a double-bend lattice (natural emittance of 2000 pmrad at 6 GeV), a triple-bend lattice (400 pmrad) and a quadruple-bend lattice (170 pmrad) were designed step by step for studying its feasibility*. For an additional emittance reduction, beam dynamic issues for a sextuple-bend lattice have been examined for the first candidate. In this case, the natural emittance is about 70 pmrad. The dynamic aperture has been enlarged by studying beam dynamic phenomena caused by nonlinear dispersion, nonlinear chromaticity, nonlinear resonance, etc., and by optimizing linear and nonlinear optics. The lattice design for the coming upgrade of SPring-8 will be presented in detail.
* K. Soutome et al., "Design Study of a very Low-emittance Storage Ring for the Future Upgrade Plan of SPring-8", Proc. of IPAC10, WEPEA032, p. 2555 (2010).
 
slides icon Slides TUOAB01 [4.812 MB]  
 
WEPC001 Beam Based Sextupole Alignment Studies for Coupling Control at the ASLS 1995
 
  • R.T. Dowd, Y.E. Tan
    ASCo, Clayton, Victoria, Australia
 
  Offsets in sextupole magnets can be a significant source of coupling in a storage ring and hinder efforts to minimize vertical emittance. Beam offsets in the sextupoles at the Australian Synchrotron Light Source were measured using a response matrix analysis in LOCO with differing magnets strengths. These results were used to obtain an estimate of offset in each sextupole as well as estimate quadrupole contributions to coupling.  
 
WEPC002 RF Separator and Septum Layout Concepts for Simultaneous Beams to RIB and FEL Users at ARIEL 1998
 
  • Y.-C. Chao, C. Gong, S.R. Koscielniak
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
 
  A ½ MW capable CW electron linac is being designed and constructed at TRIUMF in support of the existing Rare Isotope Beam program. In the simplest configuration, the beam makes a single pass through three cryomodules to the RIB production targets. However, after the construction of a recirculation path, beam could make a second pass through two cryomodules with the RF phase advance adjusted to give energy recovery. Here it is proposed to time-interleave two bunch trains, and via an RF separator and septum, to direct one single-pass train to RIB production and the second train through the energy recovery ring that contains an IR FEL. It is also the intention, in single user mode, to use the ring as an energy doubler. This paper describes the RF separation scheme and options for the extraction optics that satisfy the requirements of “simultaneous” beams to two users.  
 
WEPC003 Low-Beta Empirical Models used in Online Modeling and High Level Applications 2001
 
  • Y.-C. Chao, G. Goh
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
 
  Using empirically models for elements generated by simulations codes such as Astra in low-beta beamline to provide efficient and more accurate models for machine diagnostic and tuning is discussed. Experience of such application in the framework of XAL may also be presented.  
 
WEPC004 Comparison of the Action and Phase Analysis on LHC Orbits with Other Techniques 2004
 
  • J.F. Cardona
    UNAL, Bogota D.C, Colombia
  • R. Calaga, R. Miyamoto
    BNL, Upton, Long Island, New York, USA
  • R. Tomás
    CERN, Geneva, Switzerland
  • G. Vanbavinckhove
    NIKHEF, Amsterdam, The Netherlands
 
  Funding: DIB-Universidad Nacional de Colombia
Recently acquired turn-by-turn data of the LHC is analyzed using the action and phase jump technique. The results of this analysis show a visible variation of the action and phase plots at the interaction regions from which optic error estimations can be done. In this paper error estimations will be presented and comparisons with other existing techniques in the LHC, such as the recently implemented Segment-by-segment technique, will be discussed.
 
 
WEPC005 Concept for Controlled Transverse Emittance Transfer within a Linac Ion Beam 2007
 
  • L. Groening
    GSI, Darmstadt, Germany
 
  Generally the two transverse emittances of a linac beam are quite similar in size (round beam). However, injection into subsequent rings often imposes stronger limits for the upper allowed value to one of these emittances. Provision of flat linac beams (different transverse emittances) thus can considerable increase the injection efficiency into rings. Round-to-flat transformation has been already demonstrated for electron beams. It was also proposed for angular momentum dominated beams from Electron-Cyclotron-Resonance sources. We introduce a concept to extend the transformation to ion beams that underwent charge state stripping without requiring their extraction from an ECR source. The concept is of special interest for beams from low-charge-state / high-particle-current sources. It can be also applied to stripping of H to proton beams.  
 
WEPC006 Upgrade Plans on the Superconducting Electron Accelerator S-DALINAC 2010
 
  • M. Kleinmann, R. Eichhorn, F. Hug, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
 
  Funding: Work supported by DFG through SFB 634
The S-DALINAC is a superconducting recirculating electron accelerator with maximum design energy of 130 MeV operating in cw at 3 GHz. Even so the gradients of the superconducting cavities are well above design, their design quality factor of 3*109 have not been reached so far, leading to higher heat transfer into the liquid helium than expected. Due to the limited cooling power of the cryo-plant being 120 W, the final energy achievable in cw operation is around 85 MeV, currently. In order to provide a cw beam with the designed final energy in the future, the installation of an additional recirculation path is projected. We will report on the beam-line and the magnet design for the new recirculation path. In addition, we will present the layout of two proposed scraper-systems which will be used to remove the halo of the electron beam allowing high precision coincidence experiments with very low background for nuclear physics in the future.
 
 
WEPC007 Large Energy Acceptance Dogleg for the European XFEL Injector 2013
 
  • N. Golubeva, V. Balandin, W. Decking
    DESY, Hamburg, Germany
 
  The option to install two injectors is foreseen at the European XFEL Facility. The injectors will be located on top of each other in the same building, both with the offset of 2.75 m with respect to the main linac axis. The translation system (dogleg) from the injector axis to the main linac axis has to fulfill very tight requirements of the chromatic properties, because the energy chirp required for the downstream bunch length compression in magnetic chicanes will be created upstream in the injector linac. In this paper we present such an large energy acceptance dogleg and discuss the optical symmetries which form the basis of its design.  
 
WEPC008 Optics for the Beam Switchyard at the European XFEL 2016
 
  • N. Golubeva, V. Balandin, W. Decking
    DESY, Hamburg, Germany
 
  The European XFEL is planed as a multi-user facility with the possibility to distribute electron bunches of one beam pulse to different beamlines. The initial stage foresees two electron beamlines each serving its own set of undulators. The later addition of a third beamline is also considered in the design of the distribution system. In addition, the integration of the transport line to the beam abortion dump allows a flexible selection of the bunch repetition pattern for each beamline. The beam extraction, both in undulator beamlines and in the beamline to the dump, will be realized with fast kickers and a Lambertson septum. In this paper we describe the magnet lattice of the deflection arcs with simultaneous horizontal and vertical dispersions and the beam optics of the beam switchyard.  
 
WEPC009 Design of an Antiproton Injection and Matching Beam Line for the AD Recycler Ring 2019
 
  • O. Karamyshev, G.A. Karamysheva
    MPI-K, Heidelberg, Germany
  • O. Karamyshev, A.I. Papash
    JINR, Dubna, Moscow Region, Russia
  • M.R.F. Siggel-King, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328.
A small antiproton recycler ring (AD-Rec) for use in the MUSASHI beamline at the CERN AD has been designed by the QUASAR Group for operation at energies between 3 and 30 keV. A highly efficient beam line for capturing the beam after extraction from the trap, transporting and injecting it into the AD Rec is very important to minimize losses and full the ring up to its space charge limit. In this contribution, the beam optical and mechanical design of the injector is presented.
 
 
WEPC010 Investigations into Efficient Extraction and Acceleration of Beams from Ion Traps 2022
 
  • O. Karamyshev, G.A. Karamysheva
    MPI-K, Heidelberg, Germany
  • O. Karamyshev, A.I. Papash
    JINR, Dubna, Moscow Region, Russia
  • M.R.F. Siggel-King, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328
A number of exotic ion species, such as for example radioactive isotopes or antiprotons, are highly desirable at very low energies of some tens of keV for fundamental studies. In order to obtain cooled beams with low emittance and low momentum spread, these particles are often first captured in an ion trap, cooled and then extracted and accelerated before being used in experiments. The extraction mechanism and subsequent beam handling impacts critically on the final beam quality. In this contribnution, an optimized scheme for efficient beam extraction and acceleration from ion traps is presented. Field maps from different existing ion trap setups, such as for example the Musashi trap at CERN, are used as a basis for simulation studies into the beam dynamics. Input and final beam emittances are analyzed as a function of the extraction and acceleration field geometries and the performance of different possible scenarios is directly compared.
 
 
WEPC011 Ion Optical Design of the Low Energy Ion Beam Facility at IUAC 2025
 
  • A. Mandal, D. Kanjilal, S. Kumar, G. Rodrigues
    IUAC, New Delhi, India
 
  A Low Energy Ion Beam Facility (LEIBF) using fully permanent magnet ECR ion source (Nanogan) has been installed at Inter University Accelerator Centre (IUAC), New Delhi for fundamental research on Atomic and Molecular Physics, and Material Science. The accelerator consists of an ECR ion source, 400 kV accelerating column and an analyzing-cum switching magnet with three beam ports at 75, 90 and 105 degrees. The complete ion optics from ECR ion source to the target has been simulated using TRANSPORT* and GICOSY** ion optics codes. The ions from the ECR source are typically extracted at 15 kV which are further accelerated by 400 kV accelerating column. The analyzing cum switching magnet has been designed to analyze different beams and to switch in a particular beam line. It is a H shaped dipole magnet having pole gap of 65 mm, maximum magnetic field of 1.5 T and radius of 529 mm for 90 degree bend. The entrance and exit edge angles for three beam lines have been optimized to obtain double focus in all beam lines. The beam is further transported to target locations using electrostatic quadrupole triplet. The details of ion optics will be presented in the paper.
* K.L. Brown, D.C. Carey, Ch. Iselin and F. Rothacker: Transport, See yellow reports CERN 73-16 (1973) & CERN 80-04 (1980).
** H.Weick, GICOSY homepage, http://www-linux.gsi.de/~weick/gicosy/.
 
 
WEPC012 Steering-corrected 88 MHz QWRs for SARAF Phase II 2028
 
  • J. Rodnizki, J. Ashkenazy, D. Berkovits, Z. Horvitz
    Soreq NRC, Yavne, Israel
  • A. Kolomiets, B. Mustapha, P.N. Ostroumov
    ANL, Argonne, USA
 
  Funding: This work is partially supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
SARAF phase II linac is designed for 5 mA 40 MeV proton and deuteron beams. One option is to base the design on Quarter Wave Resonators (QWR). It is suggested to compensate the QWR non-symmetric magnetic field component by introducing a drift tube face tilt angle*. Here we explore the applicability of this steering correction scheme to the acceleration of a CW high current low β light ion beam in an end-to-end 88 MHz QWR lattice. This can serve as a case study for multi-megawatt machines that are currently being designed by ANL. An analytical approximation is used to evaluate the on-axis beam steering behavior. Two 88 MHz QWR cavities, β=0.08 and 0.15, were designed, field and beam dynamics were simulated and optimized. Using the tube face tilt angle concept the beam steering along a QWR can be reduced to the order of 0.1 mrad. Beam dynamics lattice examination including error analysis demonstrated an efficient high performance 40 MeV linac based on 3 superconducting modules with 19 QWRs (Ep < 35 MV/m and Bp < 70 mT). The fields obtained at recent ANL tests for a 73 MHz QWR (70 MV/m and 105 mT) imply that Ep is not a real limiting factor.
* P.N. Ostroumov and K. W. Shepard, PRST-AB 4, 110101 (2001).
 
 
WEPC013 Tests for Low Vertical Emittance at Diamond using LET Algorithm 2031
 
  • S.M. Liuzzo, M.E. Biagini, P. Raimondi
    INFN/LNF, Frascati (Roma), Italy
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  We present measurements recently performed at the Diamond Light Source, aimed at the achievement of low vertical emittance using the Low Emittance Tuning (LET) algorithm developed for a SuperB factory project presently in progress. The tests have been focused on the comparison between this method and the LOCO algorithm currently used at Diamond. Beam position monitor tilts estimate and multiple coupling response matrices have been introduced in the algorithm in order to optimize the procedure. After few iterations using vertical correctors and skew quadrupoles, very low vertical dispersion and emittance coupling, comparable to those obtained by LOCO, have been measured.  
 
WEPC014 Beam Dynamics Simulations of the PIAVE-ALPI Linac 2034
 
  • M. Comunian, E. Fagotti, F. Grespan, A. Palmieri, A. Pisent, C. Roncolato
    INFN/LNL, Legnaro (PD), Italy
 
  At the Legnaro National Laboratories it is operating a SuperConducting linac for nuclear studies. The ALPI linac is injected either by a XTU tandem, up to 14 MV, or by the s-c PIAVE injector, made with 2 SC-RFQ. The main part of the linac (at the present 64 cavities for a total voltage up to 48 MV) is build up in two branches connected by an achromatic and isochronous U-bend. The PIAVE-ALPI complex is able to accelerate beams up to A/q = 7. The layout of the linac ALPI is, from the point of beam dynamics, quite complex due the presence of RFQs, cavities, dipoles, magnets, etc. These elements behaviors are entirely not linear, so a small change on the settings can induce a big change in the Linac beam dynamics. An automatic tuning procedure and a full field maps description are mandatory to handle a so high number of active components. The program used at this scope is TraceWin that is able to do an envelope simulation and a full multiparticles simulation.  
 
WEPC015 Tuning Methods for HIMAC Multiple-energy Operation 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 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 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.  
 
WEPC018 Self-focusing Effects in Compact C-band Standing-wave Accelerating Structure for X-ray Imaging Applications 2046
 
  • H.R. Yang, M.-H. Cho, S.H. Kim, W. Namkung, S.J. Park
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • J.-S. Oh
    NFRI, Daejon, Republic of Korea
 
  In electron RF linacs for industrial X-ray imaging applications, compact structures are preferred for mobility. The electron beam spot size of 1 – 2 mm is required for the spatial resolution of images at the X-ray conversion target. Applying self-focusing effects to the accelerating structure, external magnets can be removed and then the accelerator system becomes more compact. We design a C-band electron linac, which is capable of producing 6-MeV, 80-mA pulsed electron beams with an RF power of 1.5 MW. It uses a bi-periodic and on-axis-coupled accelerating structure with a built-in bunching section. It uses the π/2-mode standing-waves. The first bunching cell has an asymmetric geometry which maximizes the RF phase focusing. On the other hand, the normal cells are designed for the electrostatic focusing to be maximized. In this paper, we present design details of the accelerating cells and the beam dynamics simulation by the PARMELA code.  
 
WEPC021 Optical Design of the Proton Beam Lines for the Neutron Research Complex INR RAS and Medical Application 2049
 
  • M.I. Grachev, E.V. Ponomareva
    RAS/INR, Moscow, Russia
 
  The optical design for the layout of the beam lines for the neutron research complex INR RAS and medical application on the basis of the Linear accelerator are presented here. The proposed schemes have been realized at the INR RAS. The necessary size and shape of the proton beam at the location of the neutron target are obtained. Methods and results for the tuning of the high current beams are presented in this paper.  
 
WEPC023 Beam Dynamics Simulations for the ESS-Bilbao H Ion Source 2052
 
  • I. Bustinduy, F.J. Bermejo, D. Fernandez-Cañoto, J.L. Munoz, I. Rodríguez
    ESS Bilbao, Bilbao, Spain
  • M. Eguiraun, J. Feuchtwanger, Z. Izaola
    ESS-Bilbao, Zamudio, Spain
 
  Simulations are performed for the Ion Source Test Stand (ITUR) of the ESS-Bilbao research accelerator facility. The beam dynamics is investigated as a function of the extraction voltages, the ion current, and the inclination angle of the ion source. The ITUR Penning H− ion source has the plasma aperture plate and extraction electrode inclined a certain angle with respect to the vertical axis to compensate for the Penning magnets field. The negative charged particles are extracted through a rectangular slit of 10×6 mm2. The extraction system is mainly composed of two devices, a rectangular extraction electrode and a refrigerated trumpet shaped device acting as an Einzel lens to focus the beam, and also, as a trap for neutral cesium atoms exiting from the source. Results are calculated and analyzed at the DC Current Transformer and pepperpot positions located at 245 mm and 882 mm from the ion source.  
 
WEPC024 LOCO in the ALBA Storage Ring 2055
 
  • G. Benedetti, D. Einfeld, Z. Martí, M. Muñoz
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
 
  ALBA is a 3 GeV 3rd generation light source which achieved first stored beam in February 2011, and will be commissioned during 2011. The ring comprises of 112 independent quadrupoles grouped in 14 families and 32 combined gradient dipoles powered in series. This paper reviews the process of recovering the design lattice and the symmetry of the machine, and the effects on orbit and lifetime. The main tool employ for this has been the LOCO implementation provided in the Matlab MiddleLayer. First results shows that the main effect on the symmetry is the difference between bending magnets. As this effect can not be compensated locally at present at the bendings, a global optics correction using all the quadrupoles is used.  
 
WEPC025 Modeling Results of the ALBA Booster 2058
 
  • G. Benedetti, D. Einfeld, U. Iriso, J. Marcos, Z. Martí, M. Muñoz, M. Pont
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
 
  The 3rd generation light source ALBA is in the process of being commissioned. The full energy 3 GeV booster synchrotron was commissioned in the during 2010, ramping the beam from extracted from the LINAC from an energy of 110 MeV to the 3 GeV required for injection in the storage ring. The lattice is based in combined function bending magnets, providing a small emittance beam (< 12 nmrad) at extraction. This paper reviews the agreement between the optics modeling and the measures performed during the commissioning, with special regard to the optics measurement during the ramping process. The results from the magnetic measurement for the combined magnets while ramping are included in the model to explain the movement of the tunes during the ramp.  
 
WEPC028 Record Low Beta-beat of 10% in the LHC 2061
 
  • G. Vanbavinckhove
    NIKHEF, Amsterdam, The Netherlands
  • M. Aiba
    PSI, Villigen, Switzerland
  • R. Calaga, R. Miyamoto
    BNL, Upton, Long Island, New York, USA
  • R. Tomás
    CERN, Geneva, Switzerland
 
  During the 2011 LHC run several measurements and correction campaigns were conducted. As a result a peak beta-beat of 10% level was achieved. This level, well below the specified tolerances of the LHC, improves the aperture margins and helps minimize the luminosity imbalance between the different experiments. A combination of local corrections at the insertion regions and an overall global correction were used to achieve this record low beta-beat. The sequence of the optics corrections and stability along the 2011 run are reported.  
 
WEPC029 Accuracy of the LHC Optics Measurement based on AC Dipoles 2064
 
  • R. Miyamoto, R. Calaga
    BNL, Upton, Long Island, New York, USA
  • R. Tomás, G. Vanbavinckhove
    CERN, Geneva, Switzerland
 
  Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
The tight tolerances in the LHC requires optics measurement with very good accuracy. Therefore, AC dipoles are employed as the primary devices to measure the LHC optics. The accuracy of the measurement is mainly determined by the length of the coherent signal, signal-to-noise ratio of the measurement, and the data processing to effectively suppress the noise. This paper presents numerical and experimental studies of how these factors affect the accuracy of the LHC optics measurement using the AC dipoles.
 
 
WEPC030 Measurement of Coupling Resonance Driving Terms in the LHC with AC Dipoles 2067
 
  • R. Miyamoto, R. Calaga
    BNL, Upton, Long Island, New York, USA
  • M. Aiba
    PSI, Villigen, Switzerland
  • R. Tomás, G. Vanbavinckhove
    CERN, Geneva, Switzerland
 
  Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
Transverse betatron coupling in the LHC is measured from Fourier analysis of turn-by-turn beam oscillations excited by AC dipoles. The use of the AC dipole for optics measurements induces a small systematic error which can be corrected with an appropriate data interpretation. An algorithm to apply this correction to the measurement of the coupling resonance driving terms is developed for the first time. This paper will review this new algorithm and present results of its application to the LHC.
 
 
WEPC031 Optics Corrections at RHIC 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 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.  
 
WEPC035 Double Mini-Betay Lattice for TPS Storage Ring 2082
 
  • M.-S. Chiu, H.-P. Chang, C.-T. Chen, C.C. Chiang, C.-C. Kuo, Y.C. Lee, H.-J. Tsai, C.H. Yang
    NSRRC, Hsinchu, Taiwan
 
  Based on our previous design of double mini-betay optics in one 12-m straight section, NSRRC plan to implement the double mini-betay lattice in three 12-m straight sections in TPS storage ring. Those three locations chosen for double mini-betay lattice still retain the symmetry of accelerator lattice. The two symmetric minima of the vertical beta function will be created in the center of three 12-m straight sections, respectively. We strived to obtain a linear lattice such that there is no significant increase in the natural emittance. Efforts were devoted to optimize the nonlinear beam dynamics with various simulation tools. Preliminary results will be reported.  
 
WEPC036 Coherent Synchrotron Radiation Source Based on an Isochronous Accumulator Ring with Femtosecond Electron Bunches 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.  
 
WEPC037 An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade 2088
 
  • S.D. Fartoukh
    CERN, Geneva, Switzerland
 
  A novel optics concept has been invented and developed in the context of the LHC Upgrade studies. It offers an incredibly powerful and flexible machinery in order to squeeze beta* in a symmetric or asymmetric way (so-called “round” or “flat” optics, respectively), while perfectly controlling the chromatic aberrations induced (off-momentum beta-beating, non-linear chromaticity, spurious dispersion due to the crossing angles). The basic principles of the scheme are described and a specific path for the LHC upgrade is built accordingly, only relying on the existing and well-characterized LHC-like technology, and based on the production of flat collision optics with very small beta* (7.5 cm) in the plane perpendicular to the crossing plane.  
 
WEPC038 Beam Line Design and Beam Measurement for TPS Linac 2091
 
  • K.L. Tsai, H.-P. Chang, C.-T. Chen, C.-S. Fann, K.T. Hsu, S.Y. Hsu, C.-Y. Liao, K.-K. Lin, H.M. Shih
    NSRRC, Hsinchu, Taiwan
  • K. Dunkel, C. Piel
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
 
  A beam line for examining the beam quality of TPS (Taiwan Photon Source) linac was designed and constructed in NSRRC. Beam parameters, such as energy, emittance and charge etc., are verified by using the equipments setup in the beam line for this purpose. The lattice design and its manipulation for the parameter measurements are presented in this report. Preliminary results and the tools associating with the measurement are briefly described.  
 
WEPC039 Modelling of the FETS MEBT Line using GPT 2094
 
  • D.C. Plostinar
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • R. Enparantza, M. Larrañaga
    Fundación TEKNIKER, Eibar (Gipuzkoa), Spain
 
  The Front End Test Stand project (FETS) currently under construction at Rutherford Appleton Laboratory (RAL) will accelerate a 60 mA, 2 ms, 50 pps H beam up to 3 MeV. It consists of an H ion source, a three-solenoid low energy beam transport line (LEBT), an RFQ and a medium energy beam transport line (MEBT) with a fast-slow beam chopping system. As part of the MEBT development, a GPT simulation model has been prepared. The aim is to analyse and understand the transport of intense beams and the beam behaviour in the space-charge dominated regime. The beam quality is then evaluated in terms of RMS emittance growth, beam loss, chopping efficiency and halo development. Results previously obtained with different simulation codes are discussed throughout the paper.  
 
WEPC042 Implementation of Double Mini-beta Optics at the Diamond Light Source 2103
 
  • B. Singh, R.T. Fielder, I.P.S. Martin, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  Funding: Diamond Light Source Ltd.
We report the results of the implementation of two vertical mini-beta and horizontally focusing optics at the Diamond light source, the first in August 2010 and the second in March 2011. Commissioning results of the two optics changes and experimental characterization of the optics are compared with the expected performance and theoretical modeling. The implications of a possible third customized optics are also investigated.
 
 
WEPC043 Beam Transport in a Dielectric Wall Accelerator for Intensity Modulated Proton Therapy 2106
 
  • Y.-J. Chen, D.T. Blackfield, S.D. Nelson, B. R. Poole
    LLNL, Livermore, California, USA
 
  Funding: This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA2A27344.
We are developing a compact dielectric wall accelerator (DWA) for intensity modulated proton therapy (IMPT) with a goal of fitting the compact proton DWA in a single room*. To make the accelerator compact, the DWA needs to have a very high accelerating gradient. Also, beam transport in the DWA should be done with as few external lenses as possible. We have developed a transport scheme to transport the proton bunch in the DWA and to focus the charge bunch on the patient without using any external focusing lenses. The transport scheme would allow us change the proton beam spot size on the patient easily and rapidly. Results of simulations using 3-D, EM PIC code, LSP** will be presented.
* G. J. Caporaso, Y-J Chen and S. E. Sampayan, Rev. of Accelerator Science and Technology, vol. 2, p. 253 (2009).
** Alliant Techsystems Inc., http://www.lspsuite.com/.
 
 
WEPC044 Minimizing Beam Motion in a Long-pulse Linear Induction Accelerator 2109
 
  • C. Ekdahl, E.O. Abeyta, J.B. Johnson, K. Nielsen, M.E. Schulze
    LANL, Los Alamos, New Mexico, USA
  • T.P. Hughes, C.H. Thoma
    Voss Scientific, Albuquerque, New Mexico, USA
  • C.-Y. Tom
    NSTec, Los Alamos, New Mexico, USA
 
  Funding: This work was supported by the US National Nuclear Security Agency and the US Department of Energy under contract DE-AC52-06NA25396.
The Dual Axis Radiography for Hydrodynamic Testing (DARHT) Facility at Los Alamos uses two linear induction accelerators (LIAs) for flash radiography of explosively driven experiments from orthogonal viewpoints. The DARHT Axis-II long-pulse 1.8-kA, 16.5-MeV LIA is unique. It has a beam pulse with a 1600-ns flattop during which the kinetic energy varies < 2%. During this flattop, a kicker cleaves out four short micro-pulses, which are focused onto a high-Z target and converted to bremsstrahlung for multi-pulse flash radiography of the experiments. Asymmetric injection of the beam into the solenoidal focusing field, small temporal variations in accelerating potentials, and slight cell misalignments cause the beam position to wander during the flattop. This is undesirable for radiography, because it causes a displacement of the four radiographic source spots. Since the specific energy deposition from each micro-pulse can vaporize target material, succeeding pulses impact an asymmetric object causing a distortion of the source spot. This presentation will review the physics of the beam motion and the tuning procedures we have optimized to minimize the number of shots required.
 
 
WEPC045 Transverse Emittance Reduction with Tapered Foil 2112
 
  • Y. Jiao, Y. Cai, A. Chao
    SLAC, Menlo Park, California, USA
 
  Funding: The work is supported by the U.S. Department of Energy under contract No. DE-AC02-76SF00515.
The idea of reducing transverse emittance with tapered energy-loss foil is proposed by J.M. Peterson in 1980s and recently by B. Carlsten. In present paper, we present the physical model of tapered energy-loss foil and analyze the emittance reduction using the concept of eigen emittance. The study shows that, to reduce transverse emittance, one should collimate at least 4% of particles which has either much low energy or large transverse divergence. The multiple coulomb scattering is not trivial, leading to a limited emittance reduction ratio.
 
 
WEPC047 Crab Crossing Schemes and Studies for Electron Ion Collider 2115
 
  • S. Ahmed, S.U. De Silva, Y.S. Derbenev, G.A. Krafft, V.S. Morozov, B.C. Yunn, Y. Zhang
    JLAB, Newport News, Virginia, USA
  • A. Castilla, J.R. Delayen
    ODU, Norfolk, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Medium Energy Electron Ion Collider (MEIC) at JLab has been envisioned as future high energy particle accelerator beyond 12 GeV upgrade of CEBAF. Crab crossing of colliding electron and ion beams is essential for accommodating high bunch repetition frequency in the conceptual design of MEIC. The scheme eliminates parasitic beam-beam interactions and avoids luminosity reduction by restoring head-on collisions at interaction points. This requires the separation of two beams quickly to avoid parasitic collisions and the minimization of synchrotron-betatron resonance near IP which can be fulfilled by employing the crab crossing concept first proposed by R. Palmer. Let us call this original scheme as transverse crabbing for the sake of comparison with dispersive crabbing which employs the existing accelerating/bunching RF cavities and dispersion function in the section where the cavity is installed as originally proposed by G. Jackson. In this paper, we report the beam transport and optics for both transverse and dispersive crabbing schemes followed by basic beam dynamics. Moreover, alignment and stability calculations together with synchro-betatron beam dynamics will be discussed.
 
 
WEPC048 Calibrating Transport Lines using LOCO Techniques 2118
 
  • Y. Roblin
    JLAB, Newport News, Virginia, USA
 
  Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
With the 12GeV upgrade underway at CEBAF, there is a need to recharacterize the beamlines after the modifications made to it to accommodate running at higher energies. We present a linear perturbation approach to calibrating the optics model of transport lines. This method is adapted from the LOCO method in use for storage rings. We consider the effect of quadrupole errors, dipole construction errors as well as beam position monitors and correctors calibrations. The ideal model is expanded to first order in Taylor series of the quadrupole errors. A set of difference orbits obtained by exciting the correctors along the beamline is taken, yielding the measured response matrix. An iterative procedure is invoked and the quadrupole errors as well as beam position monitors and corrector calibration factors are obtained. Here we present details of the method and results of first measurements at CEBAF in early 2011 Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes
 
 
WEPC055 Beam Orbit and Power Converter Stability at the CR 2139
 
  • A. Dolinskii, C. Dimopoulou, O.E. Gorda, S.A. Litvinov, F. Nolden, M. Steck, H. Weick
    GSI, Darmstadt, Germany
 
  For the isochronous mode operation of the CR with reference to have good properties of the mass measurements we study the sources of the beam orbit fluctuation and as consequence power converter requirements for the CR operated at BR=13 Tm. This papaer presents a summary of the different factors causing beam orbit variation, which leads to reduction of the mass measurements precision. The requirements to the power converters have been addressed.  
 
THYA01 Beam Dynamics in Positron Injector Systems for Next Generation B Factories 2857
 
  • N. Iida, H. Ikeda, T. Kamitani, M. Kikuchi, K. Oide, D.M. Zhou
    KEK, Ibaraki, Japan
 
  SuperKEKB, the upgrade plan of KEKB, aims to boost the luminosity up to 8x1035 /cm2/s. The beam energy of the Low Energy Ring (LER) is 4 GeV for positrons, and that of the High Energy Ring is 7 GeV for electrons. SuperKEKB is designed to produce low emittance beams. The horizontal and vertical emittances of the injection beams are 12.5 nm and 0.9 nm, respectively, which are one or two orders smaller than those of KEKB. The normal and maximum required charges are 4 nC and 8nC, respectively. The positron injector system consists of the source, capture systems, L-band and S-band linacs, collimators, an energy compression system (ECS), a 1.1-GeV damping ring, a bunch compression system (BCS), S-band and C-band linacs, another ECS and a beam transport line into the LER. For the low emittance beam with a huge amount of the positron charge like 8nC, some kinds of issues by the instabilities will be predicted due to such as Coherent Synchrotron Radiation (CSR), beam loading, beam-beam effects, and so on. This paper reports a design of the positron beam injection system for SuperKEKB. In addition, comparisons with SuperB are described.  
slides icon Slides THYA01 [7.572 MB]